mobile problem-specific electronic: Topics by Science.gov

Sample records for mobile problem-specific electronic

Barriers to Securing Data on Bluetooth®-Enabled Mobile Devices: A Phenomenological Study

ERIC Educational Resources Information Center

Hines, Natasha

2015-01-01

Company data on mobile devices is vulnerable and subject to unauthorized access. The general problem is that information security incidents compromise the integrity and authenticity of electronic data. The specific problem is that organizational security policies, procedures, and training do not adequately address the vulnerabilities associated…
Protecting software agents from malicious hosts using quantum computing

NASA Astrophysics Data System (ADS)

Reisner, John; Donkor, Eric

2000-07-01

We evaluate how quantum computing can be applied to security problems for software agents. Agent-based computing, which merges technological advances in artificial intelligence and mobile computing, is a rapidly growing domain, especially in applications such as electronic commerce, network management, information retrieval, and mission planning. System security is one of the more eminent research areas in agent-based computing, and the specific problem of protecting a mobile agent from a potentially hostile host is one of the most difficult of these challenges. In this work, we describe our agent model, and discuss the capabilities and limitations of classical solutions to the malicious host problem. Quantum computing may be extremely helpful in addressing the limitations of classical solutions to this problem. This paper highlights some of the areas where quantum computing could be applied to agent security.
Computer-mediated mobile messaging as collaboration support for nurses.

PubMed

Karpati, Peter; Toussaint, Pieter Jelle; Nytrø, Oystein

2009-01-01

Collaboration in hospitals is coordinated mainly by communication, which currently happens by face-to-face meetings, phone calls, pagers, notes and the electronic patient record. These habits raise problems e.g., delayed notifications and unnecessary interruptions. Dealing with these problems could save time and improve the care. Therefore we designed and prototyped a mobile messaging solution based on two specific scenarios coming from observations at a cardiology department of a Norwegian hospital. The main focus was on supporting the work of nurses. One prototype supported patient management while another one dealt with messages related to medication planning. The evaluation of the prototypes suggested that messaging-based collaboration support is worth to explore and also gave ideas for improvement.
Reciprocal Associations between Electronic Media Use and Behavioral Difficulties in Preschoolers.

PubMed

Poulain, Tanja; Vogel, Mandy; Neef, Madlen; Abicht, Franziska; Hilbert, Anja; Genuneit, Jon; Körner, Antje; Kiess, Wieland

2018-04-21

The use of electronic media has increased substantially and is already observable in young children. The present study explored associations of preschoolers’ use of electronic media with age, gender, and socio-economic status, investigated time trends, and examined reciprocal longitudinal relations between children’s use of electronic media and their behavioral difficulties. The study participants included 527 German two- to six-year-old children whose parents had provided information on their use of electronic media and their behavioral difficulties at two time points, with approximately 12 months between baseline and follow-up. The analyses revealed that older vs. younger children, as well as children from families with a lower vs. higher socio-economic status, were more often reported to use electronic media. Furthermore, the usage of mobile phones increased significantly between 2011 and 2016. Most interestingly, baseline usage of computer/Internet predicted more emotional and conduct problems at follow-up, and baseline usage of mobile phones was associated with more conduct problems and hyperactivity or inattention at follow-up. Peer relationship problems at baseline, on the other hand, increased the likelihood of using computer/Internet and mobile phones at follow-up. The findings indicate that preschoolers’ use of electronic media, especially newer media such as computer/Internet and mobile phones, and their behavioral difficulties are mutually related over time.
Reciprocal Associations between Electronic Media Use and Behavioral Difficulties in Preschoolers

PubMed Central

Vogel, Mandy; Neef, Madlen; Abicht, Franziska; Hilbert, Anja; Körner, Antje; Kiess, Wieland

2018-01-01

The use of electronic media has increased substantially and is already observable in young children. The present study explored associations of preschoolers’ use of electronic media with age, gender, and socio-economic status, investigated time trends, and examined reciprocal longitudinal relations between children’s use of electronic media and their behavioral difficulties. The study participants included 527 German two- to six-year-old children whose parents had provided information on their use of electronic media and their behavioral difficulties at two time points, with approximately 12 months between baseline and follow-up. The analyses revealed that older vs. younger children, as well as children from families with a lower vs. higher socio-economic status, were more often reported to use electronic media. Furthermore, the usage of mobile phones increased significantly between 2011 and 2016. Most interestingly, baseline usage of computer/Internet predicted more emotional and conduct problems at follow-up, and baseline usage of mobile phones was associated with more conduct problems and hyperactivity or inattention at follow-up. Peer relationship problems at baseline, on the other hand, increased the likelihood of using computer/Internet and mobile phones at follow-up. The findings indicate that preschoolers’ use of electronic media, especially newer media such as computer/Internet and mobile phones, and their behavioral difficulties are mutually related over time. PMID:29690498
A study on agent-based secure scheme for electronic medical record system.

PubMed

Chen, Tzer-Long; Chung, Yu-Fang; Lin, Frank Y S

2012-06-01

Patient records, including doctors' diagnoses of diseases, trace of treatments and patients' conditions, nursing actions, and examination results from allied health profession departments, are the most important medical records of patients in medical systems. With patient records, medical staff can instantly understand the entire medical information of a patient so that, according to the patient's conditions, more accurate diagnoses and more appropriate in-depth treatments can be provided. Nevertheless, in such a modern society with booming information technologies, traditional paper-based patient records have faced a lot of problems, such as lack of uniform formats, low data mobility, slow data transfer, illegible handwritings, enormous and insufficient storage space, difficulty of conservation, being easily damaged, and low transferability. To improve such drawbacks, reduce medical costs, and advance medical quality, paper-based patient records are modified into electronic medical records and reformed into electronic patient records. However, since electronic patient records used in various hospitals are diverse and different, in consideration of cost, it is rather difficult to establish a compatible and complete integrated electronic patient records system to unify patient records from heterogeneous systems in hospitals. Moreover, as the booming of the Internet, it is no longer necessary to build an integrated system. Instead, doctors can instantly look up patients' complete information through the Internet access to electronic patient records as well as avoid the above difficulties. Nonetheless, the major problem of accessing to electronic patient records cross-hospital systems exists in the security of transmitting and accessing to the records in case of unauthorized medical personnels intercepting or stealing the information. This study applies the Mobile Agent scheme to cope with the problem. Since a Mobile Agent is a program, which can move among hosts and automatically disperse arithmetic processes, and moves from one host to another in heterogeneous network systems with the characteristics of autonomy and mobility, decreasing network traffic, reducing transfer lag, encapsulating protocol, availability on heterogeneous platforms, fault-tolerance, high flexibility, and personalization. However, since a Mobile Agent contacts and exchanges information with other hosts or agents on the Internet for rapid exchange and access to medical information, the security is threatened. In order to solve the problem, this study proposes a key management scheme based on Lagrange interpolation formulas and hierarchical management structure to make Mobile Agents a more secure and efficient access control scheme for electronic patient record systems when applied to the access of patients' personal electronic patient records cross hospitals. Meanwhile, with the comparison of security and efficacy analyses being the feasibility of validation scheme and the basis of better efficiency, the security of Mobile Agents in the process of operation can be guaranteed, key management efficacy can be advanced, and the security of the Mobile Agent system can be protected.
Intraoperative radiation therapy using mobile electron linear accelerators: report of AAPM Radiation Therapy Committee Task Group No. 72.

PubMed

Beddar, A Sam; Biggs, Peter J; Chang, Sha; Ezzell, Gary A; Faddegon, Bruce A; Hensley, Frank W; Mills, Michael D

2006-05-01

Intraoperative radiation therapy (IORT) has been customarily performed either in a shielded operating suite located in the operating room (OR) or in a shielded treatment room located within the Department of Radiation Oncology. In both cases, this cancer treatment modality uses stationary linear accelerators. With the development of new technology, mobile linear accelerators have recently become available for IORT. Mobility offers flexibility in treatment location and is leading to a renewed interest in IORT. These mobile accelerator units, which can be transported any day of use to almost any location within a hospital setting, are assembled in a nondedicated environment and used to deliver IORT. Numerous aspects of the design of these new units differ from that of conventional linear accelerators. The scope of this Task Group (TG-72) will focus on items that particularly apply to mobile IORT electron systems. More specifically, the charges to this Task Group are to (i) identify the key differences between stationary and mobile electron linear accelerators used for IORT, (ii) describe and recommend the implementation of an IORT program within the OR environment, (iii) present and discuss radiation protection issues and consequences of working within a nondedicated radiotherapy environment, (iv) describe and recommend the acceptance and machine commissioning of items that are specific to mobile electron linear accelerators, and (v) design and recommend an efficient quality assurance program for mobile systems.
Mobile Guide System Using Problem-Solving Strategy for Museum Learning: A Sequential Learning Behavioural Pattern Analysis

ERIC Educational Resources Information Center

Sung, Y.-T.; Hou, H.-T.; Liu, C.-K.; Chang, K.-E.

2010-01-01

Mobile devices have been increasingly utilized in informal learning because of their high degree of portability; mobile guide systems (or electronic guidebooks) have also been adopted in museum learning, including those that combine learning strategies and the general audio-visual guide systems. To gain a deeper understanding of the features and…
Intrinsic phonon-limited charge carrier mobilities in thermoelectric SnSe

NASA Astrophysics Data System (ADS)

Ma, Jinlong; Chen, Yani; Li, Wu

2018-05-01

Within the past few years, tin selenide (SnSe) has attracted intense interest due to its remarkable thermoelectric potential for both n - and p -type crystals. In this work, the intrinsic phonon-limited electron/hole mobilities of SnSe are investigated using a Boltzmann transport equation based on first-principles calculated electron-phonon interactions. We find that the electrons have much larger mobilities than the holes. At room temperature, the mobilities of electrons along the a , b , and c axes are 325, 801, and 623 cm2/V s, respectively, whereas those of holes are 100, 299, and 291 cm2/V s, respectively. The anisotropy of mobilities is consistent with the reciprocal effective mass at band edges. The mode-specific analysis shows that the highest longitudinal optical phonons, rather than previously assumed acoustic phonons, dominate the scattering processes and consequently the mobilities in SnSe. The room-temperature largest mean free paths of electrons and holes in SnSe are about 21 and 13 nm, respectively.
The implementation of a mobile problem-specific electronic CEX for assessing directly observed student-patient encounters.

PubMed

Ferenchick, Gary S; Foreback, Jami; Towfiq, Basim; Kavanaugh, Kevin; Solomon, David; Mohmand, Asad

2010-01-29

Facilitating direct observation of medical students' clinical competencies is a pressing need. We developed an electronic problem-specific Clinical Evaluation Exercise (eCEX) based on a national curriculum. We assessed its feasibility in monitoring and recording students' competencies and the impact of a grading incentive on the frequency of direct observations in an internal medicine clerkship. Students (n = 56) at three clinical sites used the eCEX and comparison students (n = 56) at three other clinical sites did not. Students in the eCEX group were required to arrange 10 evaluations with faculty preceptors. Students in the second group were required to document a single, faculty observed 'Full History and Physical' encounter with a patient. Students and preceptors were surveyed at the end of each rotation. eCEX increased students' and evaluators' understanding of direct-observation objectives and had a positive impact on the evaluators' ability to provide feedback and assessments. The grading incentive increased the number of times a student reported direct observation by a resident preceptor. eCEX appears to be an effective means of enhancing student evaluation.
Psychological predictors of problem mobile phone use.

PubMed

Bianchi, Adriana; Phillips, James G

2005-02-01

Mobile phone use is banned or illegal under certain circumstances and in some jurisdictions. Nevertheless, some people still use their mobile phones despite recognized safety concerns, legislation, and informal bans. Drawing potential predictors from the addiction literature, this study sought to predict usage and, specifically, problematic mobile phone use from extraversion, self-esteem, neuroticism, gender, and age. To measure problem use, the Mobile Phone Problem Use Scale was devised and validated as a reliable self-report instrument, against the Addiction Potential Scale and overall mobile phone usage levels. Problem use was a function of age, extraversion, and low self-esteem, but not neuroticism. As extraverts are more likely to take risks, and young drivers feature prominently in automobile accidents, this study supports community concerns about mobile phone use, and identifies groups that should be targeted in any intervention campaigns.
Measurement of brightness temperature of two-dimensional electron gas in channel of a high electron mobility transistor at ultralow dissipation power

NASA Astrophysics Data System (ADS)

Korolev, A. M.; Shulga, V. M.; Turutanov, O. G.; Shnyrkov, V. I.

2016-07-01

A technically simple and physically clear method is suggested for direct measurement of the brightness temperature of two-dimensional electron gas (2DEG) in the channel of a high electron mobility transistor (HEMT). The usage of the method was demonstrated with the pseudomorphic HEMT as a specimen. The optimal HEMT dc regime, from the point of view of the "back action" problem, was found to belong to the unsaturated area of the static characteristics possibly corresponding to the ballistic electron transport mode. The proposed method is believed to be a convenient tool to explore the ballistic transport, electron diffusion, 2DEG properties and other electrophysical processes in heterostructures.
High Electron Mobility and Insights into Temperature-Dependent Scattering Mechanisms in InAsSb Nanowires.

PubMed

Boland, Jessica L; Amaduzzi, Francesca; Sterzl, Sabrina; Potts, Heidi; Herz, Laura M; Fontcuberta I Morral, Anna; Johnston, Michael B

2018-06-13

InAsSb nanowires are promising elements for thermoelectric devices, infrared photodetectors, high-speed transistors, as well as thermophotovoltaic cells. By changing the Sb alloy fraction the mid-infrared bandgap energy and thermal conductivity may be tuned for specific device applications. Using both terahertz and Raman noncontact probes, we show that Sb alloying increases the electron mobility in the nanowires by over a factor of 3 from InAs to InAs 0.65 Sb 0.35 . We also extract the temperature-dependent electron mobility via both terahertz and Raman spectroscopy, and we report the highest electron mobilities for InAs 0.65 Sb 0.35 nanowires to date, exceeding 16,000 cm 2 V -1 s -1 at 10 K.
The mobility and diffusion of ions in gases

NASA Technical Reports Server (NTRS)

Mcdaniel, E. W.; Mason, E. A.

1973-01-01

Experimental and theoretical aspects of the mobility and diffusion of ions in gases are studied in detail. Some of the subjects discussed include ion-ion interaction, boundary condition and ion and electron behavior. Also discussed in separate chapters are the problems of the diffusion coefficients and the afterglow techniques. Finally, a special chapter studies the kinetic theory of diffusion and mobility, stressing the low-, medium- and high-field theory.
Fourier-domain Mobility Spectrum Analysis (FMSA) for Characterizing Semiconductors with Multi-Electron/Hole Species

NASA Astrophysics Data System (ADS)

Cui, Boya; Kielb, Edward; Luo, Jiajun; Tang, Yang; Grayson, Matthew

Superlattices and narrow gap semiconductors often host multiple conducting species, such as electrons and holes, requiring a mobility spectral analysis (MSA) method to separate contributions to the conductivity. Here, a least-squares MSA method is introduced: the QR-algorithm Fourier-domain MSA (FMSA). Like other MSA methods, the FMSA sorts the conductivity contributions of different carrier species from magnetotransport measurements, arriving at a best fit to the experimentally measured longitudinal and Hall conductivities σxx and σxy, respectively. This method distinguishes itself from other methods by using the so-called QR-algorithm of linear algebra to achieve rapid convergence of the mobility spectrum as the solution to an eigenvalue problem, and by alternately solving this problem in both the mobility domain and its Fourier reciprocal-space. The result accurately fits a mobility range spanning nearly four orders of magnitude (μ = 300 to 1,000,000 cm2/V .s). This method resolves the mobility spectra as well as, or better than, competing MSA methods while also achieving high computational efficiency, requiring less than 30 second on average to converge to a solution on a standard desktop computer. Acknowledgement: Funded by AFOSR FA9550-15-1-0377 and AFOSR FA9550-15-1-0247.
Effectiveness of mobile electronic devices in weight loss among overweight and obese populations: a systematic review and meta-analysis.

PubMed

Khokhar, Bushra; Jones, Jessica; Ronksley, Paul E; Armstrong, Marni J; Caird, Jeff; Rabi, Doreen

2014-01-01

Mobile electronic devices, such as mobile phones and PDAs, have emerged as potentially useful tools in the facilitation and maintenance of weight loss. While RCTs have demonstrated a positive impact of mobile interventions, the extent to which mobile electronic devices are more effective than usual care methods is still being debated. Electronic databases were systematically searched for RCTs evaluating the effectiveness of mobile electronic device interventions among overweight and obese adults. Weighted mean difference for change in body weight was the primary outcome. The search strategy yielded 559 citations and of the 108 potentially relevant studies, six met the criteria. A total of 632 participants were included in the six studies reporting a mean change in body weight. Using a random-effects model, the WMD for the effect of using mobile electronic devices on reduction in body weight was -1.09 kg (95% CI -2.12, -0.05). When stratified by the type of mobile electronic device used, it suggests that interventions using mobile phones were effective at achieving weight loss, WMD = -1.78 kg (95% CI -2.92, -0.63). This systematic review and meta-analysis suggests that mobile electronic devices have the potential to facilitate weight loss in overweight and obese populations, but further work is needed to understand if these interventions have sustained benefit and how we can make these mHealth tools most effective on a large scale. As the field of healthcare increasingly utilizes novel mobile technologies, the focus must not be on any one specific device but on the best possible use of these tools to measure and understand behavior. As mobile electronic devices continue to increase in popularity and the associated technology continues to advance, the potential for the use of mobile devices in global healthcare is enormous. More RCTs with larger sample sizes need to be conducted to look at the cost-effectiveness, technical and financial feasibility of adapting such mHealth interventions in a real clinical setting.
Inhibiting Low-Frequency Vibrations Explains Exceptionally High Electron Mobility in 2,5-Difluoro-7,7,8,8-tetracyanoquinodimethane (F2-TCNQ) Single Crystals.

PubMed

Chernyshov, Ivan Yu; Vener, Mikhail V; Feldman, Elizaveta V; Paraschuk, Dmitry Yu; Sosorev, Andrey Yu

2017-07-06

Organic electronics requires materials with high charge mobility. Despite decades of intensive research, charge transport in high-mobility organic semiconductors has not been well understood. In this Letter, we address the physical mechanism underlying the exceptionally high band-like electron mobility in F 2 -TCNQ (2,5-difluoro-7,7,8,8-tetracyanoquinodimethane) single crystals among a crystal family of similar compounds F n -TCNQ (n = 0, 2, 4) using a combined experimental and theoretical approach. While electron transfer integrals and reorganization energies did not show outstanding features for F 2 -TCNQ, Raman spectroscopy and solid-state DFT indicated that the frequency of the lowest vibrational mode is nearly twice higher in the F 2 -TCNQ crystal than in TCNQ and F 4 -TCNQ. This phenomenon is explained by the specific packing motif of F 2 -TCNQ with only one molecule per primitive cell so that electron-phonon interaction decreases and the electron mobility increases. We anticipate that our findings will encourage investigators for the search and design of organic semiconductors with one molecule per primitive cell and/or the poor low-frequency vibrational spectrum.
Mobile transporter path planning

NASA Technical Reports Server (NTRS)

Baffes, Paul; Wang, Lui

1990-01-01

The use of a genetic algorithm (GA) for solving the mobile transporter path planning problem is investigated. The mobile transporter is a traveling robotic vehicle proposed for the space station which must be able to reach any point of the structure autonomously. Elements of the genetic algorithm are explored in both a theoretical and experimental sense. Specifically, double crossover, greedy crossover, and tournament selection techniques are examined. Additionally, the use of local optimization techniques working in concert with the GA are also explored. Recent developments in genetic algorithm theory are shown to be particularly effective in a path planning problem domain, though problem areas can be cited which require more research.
Low nonalloyed Ohmic contact resistance to nitride high electron mobility transistors using N-face growth

NASA Astrophysics Data System (ADS)

Wong, Man Hoi; Pei, Yi; Palacios, Tomás; Shen, Likun; Chakraborty, Arpan; McCarthy, Lee S.; Keller, Stacia; DenBaars, Steven P.; Speck, James S.; Mishra, Umesh K.

2007-12-01

Nonalloyed Ohmic contacts on Ga-face n+-GaN/AlGaN/GaN high electron mobility transistor (HEMT) structures typically have significant contact resistance to the two-dimensional electron gas (2DEG) due to the AlGaN barrier. By growing the HEMT structure inverted on the N-face, electrons from the contacts were able to access the 2DEG without going through an AlGaN layer. A low contact resistance of 0.16Ωmm and specific contact resistivity of 5.5×10-7Ωcm2 were achieved without contact annealing on the inverted HEMT structure.
Influence of the electron-cation interaction on electron mobility in dye-sensitized ZnO and TiO2 nanocrystals: a study using ultrafast terahertz spectroscopy.

PubMed

Nemec, H; Rochford, J; Taratula, O; Galoppini, E; Kuzel, P; Polívka, T; Yartsev, A; Sundström, V

2010-05-14

Charge transport and recombination in nanostructured semiconductors are poorly understood key processes in dye-sensitized solar cells. We have employed time-resolved spectroscopies in the terahertz and visible spectral regions supplemented with Monte Carlo simulations to obtain unique information on these processes. Our results show that charge transport in the active solar cell material can be very different from that in nonsensitized semiconductors, due to strong electrostatic interaction between injected electrons and dye cations at the surface of the semiconductor nanoparticle. For ZnO, this leads to formation of an electron-cation complex which causes fast charge recombination and dramatically decreases the electron mobility even after the dissociation of the complex. Sensitized TiO2 does not suffer from this problem due to its high permittivity efficiently screening the charges.

Mobile robot motion estimation using Hough transform

NASA Astrophysics Data System (ADS)

Aldoshkin, D. N.; Yamskikh, T. N.; Tsarev, R. Yu

2018-05-01

This paper proposes an algorithm for estimation of mobile robot motion. The geometry of surrounding space is described with range scans (samples of distance measurements) taken by the mobile robot’s range sensors. A similar sample of space geometry in any arbitrary preceding moment of time or the environment map can be used as a reference. The suggested algorithm is invariant to isotropic scaling of samples or map that allows using samples measured in different units and maps made at different scales. The algorithm is based on Hough transform: it maps from measurement space to a straight-line parameters space. In the straight-line parameters, space the problems of estimating rotation, scaling and translation are solved separately breaking down a problem of estimating mobile robot localization into three smaller independent problems. The specific feature of the algorithm presented is its robustness to noise and outliers inherited from Hough transform. The prototype of the system of mobile robot orientation is described.
Mobile healthcare informatics.

PubMed

Siau, Keng; Shen, Zixing

2006-06-01

Advances in wireless technology give pace to the rapid development of mobile applications. The coming mobile revolution will bring dramatic and fundamental changes to our daily life. It will influence the way we live, the way we do things, and the way we take care of our health. For the healthcare industry, mobile applications provide a new frontier in offering better care and services to patients, and a more flexible and mobile way of communicating with suppliers and patients. Mobile applications will provide important real time data for patients, physicians, insurers, and suppliers. In addition, it will revolutionalize the way information is managed in the healthcare industry and redefine the doctor - patient communication. This paper discusses different aspects of mobile healthcare. Specifically, it presents mobile applications in healthcare, and discusses possible challenges facing the development of mobile applications. Obstacles in developing mobile healthcare applications include mobile device limitations, wireless networking problems, infrastructure constraints, security concerns, and user distrust. Research issues in resolving or alleviating these problems are also discussed in the paper.
Effect of Energy Alignment, Electron Mobility, and Film Morphology of Perylene Diimide Based Polymers as Electron Transport Layer on the Performance of Perovskite Solar Cells.

PubMed

Guo, Qiang; Xu, Yingxue; Xiao, Bo; Zhang, Bing; Zhou, Erjun; Wang, Fuzhi; Bai, Yiming; Hayat, Tasawar; Alsaedi, Ahmed; Tan, Zhan'ao

2017-03-29

For organic-inorganic perovskite solar cells (PerSCs), the electron transport layer (ETL) plays a crucial role in efficient electron extraction and transport for high performance PerSCs. Fullerene and its derivatives are commonly used as ETL for p-i-n structured PerSCs. However, these spherical small molecules are easy to aggregate with high annealing temperature and thus induce morphology stability problems. N-type conjugated polymers are promising candidates to overcome these problems due to the tunable energy levels, controllable aggregation behaviors, and good film formation abilities. Herein, a series of perylene diimide (PDI) based polymers (PX-PDIs), which contain different copolymeried units (X), including vinylene (V), thiophene (T), selenophene (Se), dibenzosilole (DBS), and cyclopentadithiophene (CPDT), are introduced as ETL for p-i-n structured PerSCs. The effect of energy alignment, electron mobility, and film morphology of these ETLs on the photovoltaic performance of the PerSCs are fully investigated. Among the PX-PDIs, PV-PDI demonstrates the deeper LUMO energy level, the highly delocalized LUMO electron density, and a better planar structure, making it the best electron transport material for PerSCs. The planar heterojunction PerSC with PV-PDI as ETL achieves a power conversion efficiency (PCE) of 10.14%, among the best values for non-fullerene based PerSCs.
Mobile phone related-hazards and subjective hearing and vision symptoms in the Saudi population.

PubMed

Meo, Sultan A; Al-Drees, Abdul M

2005-01-01

Over the past decade utilization of mobile phones has dramatically increased. They are now an essential part of business, commerce, and communication, however, their use may lead to health problems. Therefore, the present study was designed to investigate a link between the use of mobile phones and hearing and vision symptoms in the Saudi population and also to contribute to the increase in social awareness of health problems associated with the use of these devices. A total of 873 (57.04% of males and 39.86% of females) subjects using mobile phones were invited to participate in the presented study. A structured questionnaire was distributed among them to collect a detailed medical history. The Chi-square test was employed to observe the relationship between duration of calls and hearing and vision complaints. The present study showed an association between the use of mobile phones and hearing and vision complaints. About 34.59% of problems were related with impaired hearing, ear ache and/or warmth on the ear, and 5.04% of complaints with the decreased and/or blurred vision. It is concluded that the use of mobile phone is a health risk factor, and thus it is suggested that excessive use of mobile phones should be avoided and social awareness increased through health promotion activities, such as group discussions or public presentations and via electronic and printed media sources.
Development of mobile platform integrated with existing electronic medical records.

PubMed

Kim, YoungAh; Kim, Sung Soo; Kang, Simon; Kim, Kyungduk; Kim, Jun

2014-07-01

This paper describes a mobile Electronic Medical Record (EMR) platform designed to manage and utilize the existing EMR and mobile application with optimized resources. We structured the mEMR to reuse services of retrieval and storage in mobile app environments that have already proven to have no problem working with EMRs. A new mobile architecture-based mobile solution was developed in four steps: the construction of a server and its architecture; screen layout and storyboard making; screen user interface design and development; and a pilot test and step-by-step deployment. This mobile architecture consists of two parts, the server-side area and the client-side area. In the server-side area, it performs the roles of service management for EMR and documents and for information exchange. Furthermore, it performs menu allocation depending on user permission and automatic clinical document architecture document conversion. Currently, Severance Hospital operates an iOS-compatible mobile solution based on this mobile architecture and provides stable service without additional resources, dealing with dynamic changes of EMR templates. The proposed mobile solution should go hand in hand with the existing EMR system, and it can be a cost-effective solution if a quality EMR system is operated steadily with this solution. Thus, we expect this example to be shared with hospitals that currently plan to deploy mobile solutions.
Development of Mobile Platform Integrated with Existing Electronic Medical Records

PubMed Central

Kim, YoungAh; Kang, Simon; Kim, Kyungduk; Kim, Jun

2014-01-01

Objectives This paper describes a mobile Electronic Medical Record (EMR) platform designed to manage and utilize the existing EMR and mobile application with optimized resources. Methods We structured the mEMR to reuse services of retrieval and storage in mobile app environments that have already proven to have no problem working with EMRs. A new mobile architecture-based mobile solution was developed in four steps: the construction of a server and its architecture; screen layout and storyboard making; screen user interface design and development; and a pilot test and step-by-step deployment. This mobile architecture consists of two parts, the server-side area and the client-side area. In the server-side area, it performs the roles of service management for EMR and documents and for information exchange. Furthermore, it performs menu allocation depending on user permission and automatic clinical document architecture document conversion. Results Currently, Severance Hospital operates an iOS-compatible mobile solution based on this mobile architecture and provides stable service without additional resources, dealing with dynamic changes of EMR templates. Conclusions The proposed mobile solution should go hand in hand with the existing EMR system, and it can be a cost-effective solution if a quality EMR system is operated steadily with this solution. Thus, we expect this example to be shared with hospitals that currently plan to deploy mobile solutions. PMID:25152837
Applang - A DSL for specification of mobile applications for android platform based on textX

NASA Astrophysics Data System (ADS)

Kosanović, Milan; Dejanović, Igor; Milosavljević, Gordana

2016-06-01

Mobile platforms become a ubiquitous part of our daily lives thus making more pressure to software developers to develop more applications faster and with the support for different mobile operating systems. To foster the faster development of mobile services and applications and to support various mobile operating systems a new software development approaches must be undertaken. Domain-Specific Languages (DSL) are a viable approach that promise to solve a problem of target platform diversity as well as to facilitate rapid application development and shorter time-to-market. This paper presents Applang, a DSL for the specification of mobile applications for the Android platform, based on textX meta-language. The application is described using Applang DSL and the source code for a target platform is automatically generated by the provided code generator. The same application defined using single Applang source can be transformed to various targets with little or no manual modifications.
First-principles method for electron-phonon coupling and electron mobility: Applications to two-dimensional materials

NASA Astrophysics Data System (ADS)

Gunst, Tue; Markussen, Troels; Stokbro, Kurt; Brandbyge, Mads

2016-01-01

We present density functional theory calculations of the phonon-limited mobility in n -type monolayer graphene, silicene, and MoS2. The material properties, including the electron-phonon interaction, are calculated from first principles. We provide a detailed description of the normalized full-band relaxation time approximation for the linearized Boltzmann transport equation (BTE) that includes inelastic scattering processes. The bulk electron-phonon coupling is evaluated by a supercell method. The method employed is fully numerical and does therefore not require a semianalytic treatment of part of the problem and, importantly, it keeps the anisotropy information stored in the coupling as well as the band structure. In addition, we perform calculations of the low-field mobility and its dependence on carrier density and temperature to obtain a better understanding of transport in graphene, silicene, and monolayer MoS2. Unlike graphene, the carriers in silicene show strong interaction with the out-of-plane modes. We find that graphene has more than an order of magnitude higher mobility compared to silicene in the limit where the silicene out-of-plane interaction is reduced to zero (by substrate interaction, clamping, or similar). If the out-of-plane interaction is not actively reduced, the mobility of silicene will essentially be zero. For MoS2, we obtain several orders of magnitude lower mobilities compared to graphene in agreement with other recent theoretical results. The simulations illustrate the predictive capabilities of the newly implemented BTE solver applied in simulation tools based on first-principles and localized basis sets.
An object-oriented mobile health system with usability features.

PubMed

Escarfullet, Krystle; Moore, Cantera; Tucker, Shari; Wei, June

2012-01-01

Mobile health (m-health) comprises the concept of utilising mobile devices to carry out the task of viewing electronic medical records, reserving medical appointments with a patient's medical provider and electronically refilling prescriptions. This paper aims at developing a m-health system to improve usability from a user's perspective. Specifically, it first developed a m-health model by logically linking characteristics of the m-health system together based on information flows. Then, the system requirements were collected by using a developed questionnaire. These requirements were structured and further in-depth analysis was conducted by using an object-oriented approach based on unified modelling language, such as use-case, sequence and analysis class diagrams. This research will be beneficial to decision makers and developers in the mobile healthcare industry.
Exploring Credit Mobility and Major-Specific Pathways: A Policy Analysis and Student Perspective on Community College to University Transfer

ERIC Educational Resources Information Center

Hodara, Michelle; Martinez-Wenzl, Mary; Stevens, David; Mazzeo, Christopher

2017-01-01

Objective: Problems with credit mobility, or the transfer of credits from a sending to a receiving institution, may be one reason why community college transfer students have low rates of bachelor's degree completion. This study investigates different policy approaches to credit mobility and how college staff and students experience transfer at…
Silicon carbide: A unique platform for metal-oxide-semiconductor physics

NASA Astrophysics Data System (ADS)

Liu, Gang; Tuttle, Blair R.; Dhar, Sarit

2015-06-01

A sustainable energy future requires power electronics that can enable significantly higher efficiencies in the generation, distribution, and usage of electrical energy. Silicon carbide (4H-SiC) is one of the most technologically advanced wide bandgap semiconductor that can outperform conventional silicon in terms of power handling, maximum operating temperature, and power conversion efficiency in power modules. While SiC Schottky diode is a mature technology, SiC power Metal Oxide Semiconductor Field Effect Transistors are relatively novel and there is large room for performance improvement. Specifically, major initiatives are under way to improve the inversion channel mobility and gate oxide stability in order to further reduce the on-resistance and enhance the gate reliability. Both problems relate to the defects near the SiO2/SiC interface, which have been the focus of intensive studies for more than a decade. Here we review research on the SiC MOS physics and technology, including its brief history, the state-of-art, and the latest progress in this field. We focus on the two main scientific problems, namely, low channel mobility and bias temperature instability. The possible mechanisms behind these issues are discussed at the device physics level as well as the atomic scale, with the support of published physical analysis and theoretical studies results. Some of the most exciting recent progress in interface engineering for improving the channel mobility and fundamental understanding of channel transport is reviewed.
Robust and Cost-Efficient Communication Based on SNMP in Mobile Networks

NASA Astrophysics Data System (ADS)

Ryu, Sang-Hoon; Baik, Doo-Kwon

A main challenge in the design of this mobile network is the development of dynamic routing protocols that can efficiently find routes between two communicating nodes. Multimedia streaming services are receiving considerable interest in the mobile network business. An entire mobile network may change its point of attachment to the Internet. The mobile network is operated by a basic specification to support network mobility called Network Mobility (NEMO) Basic Support. However, NEMO basic Support mechanism has some problem in continuous communication. In this paper, we propose robust and cost-efficient algorithm. And we simulate proposed method and conclude some remarks.
A Mobile and Intelligent Patient Diary for Chronic Disease Self-Management.

PubMed

Van Woensel, William; Roy, Patrice C; Abidi, Samina R; Abidi, Syed S R

2015-01-01

By involving patients in their own long-term care, patient self-management approaches aim to increase self-sufficiency and reduce healthcare costs. For example, electronic patient diaries enable patients to collect health data autonomously, increasing self-reliance and reducing strain on health professionals. By deploying patient diaries on mobile platforms, health data collection can occur at any time and place, increasing the mobility of chronic patients who typically need to enter health data frequently. Importantly, an opportunity also arises for mobile clinical decision support, where health feedback is directly issued to patients without relying on connectivity or remote servers. Regardless of the specific self-management strategy, patient and healthcare provider adoption are crucial. Tailoring the system towards the particular patient and toward institution-specific clinical pathways is essential to increasing acceptance. In this paper we discuss a mobile patient diary realizing both the opportunities and challenges of mobile deployment.
Assessment of the effector function of CMV-specific CTLs isolated using MHC-multimers from granulocyte-colony stimulating factor mobilized peripheral blood.

PubMed

Beloki, Lorea; Ciaurriz, Miriam; Mansilla, Cristina; Zabalza, Amaya; Perez-Valderrama, Estela; Samuel, Edward R; Lowdell, Mark W; Ramirez, Natalia; Olavarria, Eduardo

2015-05-20

Adoptive transfer of CMV-specific T cells has shown promising results in preventing pathological effects caused by opportunistic CMV infection in immunocompromised patients following allogeneic hematopoietic stem cell transplantation. The majority of studies have used steady-state leukapheresis for CMV-reactive product manufacture, a collection obtained prior to or months after G-CSF mobilization, but the procurement of this additional sample is often not available in the unrelated donor setting. If the cellular product for adoptive immunotherapy could be generated from the same G-CSF mobilized collection, the problems associated with the additional harvest could be overcome. Despite the tolerogenic effects associated with G-CSF mobilization, recent studies described that CMV-primed T cells generated from mobilized donors remain functional. MHC-multimers are potent tools that allow the rapid production of antigen-specific CTLs. Therefore, in the present study we have assessed the feasibility and efficacy of CMV-specific CTL manufacture from G-CSF mobilized apheresis using MHC-multimers. CMV-specific CTLs can be efficiently isolated from G-CSF mobilized samples with Streptamers and are able to express activation markers and produce cytokines in response to antigenic stimulation. However, this anti-viral functionality is moderately reduced when compared to non-mobilized products. The translation of Streptamer technology for the isolation of anti-viral CTLs from G-CSF mobilized PBMCs into clinical practice would widen the number of patients that could benefit from this therapeutic strategy, although our results need to be taken into consideration before the infusion of antigen-specific T cells obtained from G-CSF mobilized samples.
Research on mobile electronic commerce security technology based on WPKI

NASA Astrophysics Data System (ADS)

Zhang, Bo

2013-07-01

Through the in-depth study on the existing mobile e-commerce and WAP protocols, this paper presents a security solution of e-commerce system based on WPKI, and describes its implementation process and specific implementation details. This solution uniformly distributes the key used by the various participating entities , to fully ensure the confidentiality, authentication, fairness and integrity of mobile e-commerce payments, therefore has some pract ical value for improving the security of e-commerce system.
Overlooked Transport Participants - Mentally Impaired but Still Mobile

NASA Astrophysics Data System (ADS)

Vlk, Tamara; Wanjek, Monika; Berkowitsch, Claudia; Hauger, Georg

2017-10-01

Providing an inclusive transport system is a global ambition. Whereas, mobility needs and mobility barriers of people suffering from a physical impairment have already been observed frequently, people suffering from mental impairments (due to e.g. anxiety disorders, obsessive-compulsive disorders, dementia or other degenerative diseases) are often overlooked. Numerous studies already suggest that the number of people with mental impairment will significantly increase due to the demographic change and is also shown by the prevalence of mental diseases. Whereby, not even the data collected do necessarily give the full picture of the actual situation. Thus, the importance of mobility needs and mobility problems of people with mental impairments will gain dramatically. Participating in the transport system is a basic need that furthermore requires the ability of adopting different roles (e.g. driver, pedestrian). Due to explanatory studies of the authors, it could be shown what kind of problems people with mental impairment are faced with while participating in the transport system or interacting in public space. Thus, these studies represent the first step that is needed to consider the specific needs of people with mental impairments in future planning. The identified problems of people who are suffering from mental impairment are various. Thereby it can be distinguished between problems triggered by structural (e.g. absence of emergency buttons, spacious stations), organisational (e.g. absence of security stuff, lacking information according time table of transit) or social conditions (e.g. crowed places or vehicles, stigmatisation). This paper presents an overall view of specific requirements of people with mental impairment and suggests possible solutions for planning and designing an inclusive transport system.
Method to quantify the delocalization of electronic states in amorphous semiconductors and its application to assessing charge carrier mobility of p -type amorphous oxide semiconductors

NASA Astrophysics Data System (ADS)

de Jamblinne de Meux, A.; Pourtois, G.; Genoe, J.; Heremans, P.

2018-01-01

Amorphous semiconductors are usually characterized by a low charge carrier mobility, essentially related to their lack of long-range order. The development of such material with higher charge carrier mobility is hence challenging. Part of the issue comes from the difficulty encountered by first-principles simulations to evaluate concepts such as the electron effective mass for disordered systems since the absence of periodicity induced by the disorder precludes the use of common concepts derived from condensed matter physics. In this paper, we propose a methodology based on first-principles simulations that partially solves this problem, by quantifying the degree of delocalization of a wave function and of the connectivity between the atomic sites within this electronic state. We validate the robustness of the proposed formalism on crystalline and molecular systems and extend the insights gained to disordered/amorphous InGaZnO4 and Si. We also explore the properties of p -type oxide semiconductor candidates recently reported to have a low effective mass in their crystalline phases [G. Hautier et al., Nat. Commun. 4, 2292 (2013), 10.1038/ncomms3292]. Although in their amorphous phase none of the candidates present a valence band with delocalization properties matching those found in the conduction band of amorphous InGaZnO4, three of the seven analyzed materials show some potential. The most promising candidate, K2Sn2O3 , is expected to possess in its amorphous phase a slightly higher hole mobility than the electron mobility in amorphous silicon.
Specific features of electron scattering in uniaxially deformed n-Ge single crystals in the presence of radiation defects

NASA Astrophysics Data System (ADS)

Luniov, S. V.; Zimych, A. I.; Nazarchuk, P. F.; Maslyuk, V. T.; Megela, I. G.

2016-12-01

Temperature dependencies for concentration of electrons and the Hall mobility for unirradiated and irradiated by the flow of electrons ? single crystals ?, with the energy of ?, for different values of uniaxial pressures along the crystallographic directions ?, ? and ? are obtained on the basis of piezo-Hall effect measurements. Non-typical growth of the Hall mobility of electrons for irradiated single crystals ? in comparison with unirradiated with the increasing of value of uniaxial pressures along the crystallographic directions ? (for the entire range of the investigated temperatures) and ? (to temperatures ?) has been revealed. Such an effect of the Hall mobility increase for uniaxially deformed single crystals ? is explained by the reduction of gradients of a resistance as a result of reduction in the amplitude of a large-scale potential with deformation and concentration of charged A-centers in the process of their recharge by the increasing of uniaxial pressure and consequently the probability of scattering on these centers. Theoretical calculations for temperature dependencies of the Hall mobility for uniaxially deformed single crystals ? in terms of the electrons scattering on the ions of shallow donors, acoustic, optical and intervalley phonons, regions of disordering and large-scale potential is good conformed to the corresponding experimental results at temperatures T<220 K for the case of uniaxial pressures along the crystallographic directions ? and ? and for temperatures ? when the uniaxial pressure is directed along the crystallographic directions ?. The mechanism of electron scattering on a charged radiation defects (which correspond to the deep energy levels of A-centers) 'is turned off' for the given temperatures due to the uniaxial pressure. Reduction of the Hall mobility in transition through a maximum of dependence ? with the increasing temperature for cases of the uniaxial deformation of the irradiated single crystals ? along the crystallographic directions ? and ? is explained by the deforming redistribution of electrons between the minima of conduction band of germanium with different mobility.
Mobility enhancement in crystalline In-Ga-Zn-oxide with In-rich compositions

DOE Office of Scientific and Technical Information (OSTI.GOV)

Tsutsui, Kazuhiro; Matsubayashi, Daisuke; Ishihara, Noritaka

The electron mobility of In-Ga-Zn-oxide (IGZO) is known to be enhanced by higher In content. We theoretically investigated the mobility-enhancement mechanism by proposing an In-Ga-Zn-disorder scattering model for an In-rich crystalline IGZO (In{sub 1+x}Ga{sub 1−x}O{sub 3}(ZnO){sub m} (0 < x < 1, m > 0)) thin film. The obtained theoretical mobility was found to be in agreement with experimental Hall mobility for a crystalline In{sub 1.5}Ga{sub 0.5}O{sub 3}(ZnO) (or In{sub 3}GaZn{sub 2}O{sub 8}) thin film. The mechanism specific to In-rich crystalline IGZO thin films is based on three types of Coulomb scattering potentials that originate from effective valence differences. In this study, the In-Ga-Zn-disorder scattering modelmore » indicates that the effective valence of the In{sup 3+} ions in In-rich crystalline IGZO thin films significantly affects their electron mobility.« less
Design of a Prototype Mobile Application to Make Mathematics Education More Realistic

ERIC Educational Resources Information Center

Jordaan, Dawid B.; Laubscher, Dorothy J.; Blignaut, A. Seugnet

2017-01-01

To enter the world of work, students require skills which include flexibility, critical thinking, problem solving, collaboration and communication. The use of mobile technologies which are specifically created for a context could stimulate motivation in students to recognise the relevance of Mathematics in the real world. South Africa in…

QM/QM approach to model energy disorder in amorphous organic semiconductors.

PubMed

Friederich, Pascal; Meded, Velimir; Symalla, Franz; Elstner, Marcus; Wenzel, Wolfgang

2015-02-10

It is an outstanding challenge to model the electronic properties of organic amorphous materials utilized in organic electronics. Computation of the charge carrier mobility is a challenging problem as it requires integration of morphological and electronic degrees of freedom in a coherent methodology and depends strongly on the distribution of polaron energies in the system. Here we represent a QM/QM model to compute the polaron energies combining density functional methods for molecules in the vicinity of the polaron with computationally efficient density functional based tight binding methods in the rest of the environment. For seven widely used amorphous organic semiconductor materials, we show that the calculations are accelerated up to 1 order of magnitude without any loss in accuracy. Considering that the quantum chemical step is the efficiency bottleneck of a workflow to model the carrier mobility, these results are an important step toward accurate and efficient disordered organic semiconductors simulations, a prerequisite for accelerated materials screening and consequent component optimization in the organic electronics industry.
Rogue waves lead to the instability in GaN semiconductors

PubMed Central

Yahia, M. E.; Tolba, R. E.; El-Bedwehy, N. A.; El-Labany, S. K.; Moslem, W. M.

2015-01-01

A new approach to understand the electron/hole interfaced plasma in GaN high electron mobility transistors (HEMTs). A quantum hydrodynamic model is constructed to include electrons/holes degenerate pressure, Bohm potential, and the exchange/correlation effect and then reduced to the nonlinear Schrödinger equation (NLSE). Numerical analysis of the latter predicts the rough (in)stability domains, which allow for the rogue waves to occur. Our results might give physical solution rather than the engineering one to the intrinsic problems in these high frequency/power transistors. PMID:26206731
Electroluminescence of hot electrons in AlGaN/GaN high-electron-mobility transistors under radio frequency operation

DOE Office of Scientific and Technical Information (OSTI.GOV)

Brazzini, Tommaso, E-mail: tommaso.brazzini@bristol.ac.uk; Sun, Huarui; Uren, Michael J.

2015-05-25

Hot electrons in AlGaN/GaN high electron mobility transistors are studied during radio frequency (RF) and DC operation by means of electroluminescence (EL) microscopy and spectroscopy. The measured EL intensity is decreased under RF operation compared to DC at the same average current, indicating a lower hot electron density. This is explained by averaging the DC EL intensity over the measured load line used in RF measurements, giving reasonable agreement. In addition, the hot electron temperature is lower by up to 15% under RF compared to DC, again at least partially explainable by the weighted averaging along the specific load line.more » However, peak electron temperature under RF occurs at high V{sub DS} and low I{sub DS} where EL is insignificant suggesting that any wear-out differences between RF and DC stress of the devices will depend on the balance between hot-carrier and field driven degradation mechanisms.« less
Perceived self-efficacy and specific self-reported outcomes in persons with lower-limb amputation using a non-microprocessor-controlled versus a microprocessor-controlled prosthetic knee.

PubMed

Möller, Saffran; Hagberg, Kerstin; Samulesson, Kersti; Ramstrand, Nerrolyn

2018-04-01

To measure self-efficacy in a group of individuals who have undergone a lower-limb amputation and investigate the relationship between self-efficacy and prosthetic-specific outcomes including prosthetic use, mobility, amputation-related problems and global health. A second purpose was to examine if differences exist in outcomes based upon the type of prosthetic knee unit being used. Cross-sectional study using the General Self-Efficacy (GSE) Scale and the Questionnaire for Persons with a Transfemoral Amputation (Q-TFA). Forty-two individuals participated in the study. Twenty-three used a non-microprocessor-controlled prosthetic knee joint (non-MPK) and 19 used a microprocessor-controlled prosthetic knee joint (MPK). The study sample had quite high GSE scores (32/40). GSE scores were significantly correlated to the Q-TFA prosthetic use, mobility and problem scores. High GSE scores were related to higher levels of prosthetic use, mobility, global scores and negatively related to problem score. No significant difference was observed between individuals using a non-MPK versus MPK joints. Individuals with high self-efficacy used their prosthesis to a higher degree and high self-efficacy was related to higher level of mobility, global scores and fewer problems related to the amputation in individuals who have undergone a lower-limb amputation and were using a non-MPK or MPK knee. Implications for rehabilitation Perceived self-efficacy has has been shown to be related to quality of life, prosthetic mobility and capability as well as social activities in daily life. Prosthetic rehabilitation is primary focusing on physical improvement rather than psychological interventions. More attention should be directed towards the relationship between self-efficacy and prosthetic related outcomes during prosthetic rehabilitation after a lower-limb amputation.
National data showed that delayed sleep in six-year-old children was associated with excessive use of electronic devices at 12 years.

PubMed

Kato, Tsuguhiko; Yorifuji, Takashi; Yamakawa, Michiyo; Inoue, Sachiko

2018-01-31

Cross-sectional studies have shown associations between adolescent sleep problems and the use of electronic devices, such as mobile phones, but longitudinal studies remain scarce. We explored any association between delayed bedtimes at six years old and the excessive use of electronic devices at 12 years of age. Texting was a prime focus. We analysed 9607 adolescents who owned mobile phones in 2013 using the Japanese Longitudinal Survey of Newborns in the 21st Century, which started in 2001. The outcomes were daily excessive use of a mobile phone, television (TV) and video games. Delayed bedtime at the age of six years was associated with excessive texting at weekends. The adjusted odds ratios and 95% confidence intervals obtained from logistic regression analyses were 1.88 (1.14-3.10) for the 10-11 pm group and 1.98 (1.08-3.63) for the after 11 pm group, compared with the before 9 pm group. Later bedtimes were also associated with increased risks of excessive TV viewing and video game use. Our study indicated that six-year-olds who regularly stayed up late at night used electronic devices more frequently, or for longer, at the age of 12. Parents need to be more aware of links between sleep issues and electronic devices. ©2018 Foundation Acta Paediatrica. Published by John Wiley & Sons Ltd.
The Mobile Internet -The Next Big Thing. Electrons & Photons: You Need Both! (BRIEFING CHARTS)

DTIC Science & Technology

2007-03-05

Links Network Centric Warfighting Comms Wired & Wireless Links 20th Century 21th Century The Military Comms Problem Network Centric Operationst t i ti...Small Unit Operations TEL Underwater Vehicles & Towed Arrays RC-135V Rivet Joint Tier II+ UAV Global Hawk E-2C Hawkeye Networked Manned and Unmanned...RF Front-End Solutions ● >20 DARPA/MTO RF Programs across the spectrum - RF & Mixed Signal Electronics - Analog & Digital Photonics Enables Network
Electron Mobility in γ -Al2O3/SrTiO3

NASA Astrophysics Data System (ADS)

Christensen, D. V.; Frenkel, Y.; Schütz, P.; Trier, F.; Wissberg, S.; Claessen, R.; Kalisky, B.; Smith, A.; Chen, Y. Z.; Pryds, N.

2018-05-01

One of the key issues in engineering oxide interfaces for electronic devices is achieving high electron mobility. SrTiO3 -based interfaces with high electron mobility have gained a lot of interest due to the possibility of combining quantum phenomena with the many functionalities exhibited by SrTiO3 . To date, the highest electron mobility (140 000 cm2/V s at 2 K) is obtained by interfacing perovskite SrTiO3 with spinel γ -Al2O3 . The origin of the high mobility, however, remains poorly understood. Here, we investigate the scattering mechanisms limiting the mobility in γ -Al2O3/SrTiO3 at temperatures between 2 and 300 K and over a wide range of sheet carrier densities. For T >150 K , we find that the mobility is limited by longitudinal optical phonon scattering. For large sheet carrier densities (>8 ×1013 cm-2 ), the screened electron-phonon coupling leads to room-temperature mobilities up to μ ˜12 cm2/V s . For 5 K
A mobile robot system for ground servicing operations on the space shuttle

NASA Astrophysics Data System (ADS)

Dowling, K.; Bennett, R.; Blackwell, M.; Graham, T.; Gatrall, S.; O'Toole, R.; Schempf, H.

1992-11-01

A mobile system for space shuttle servicing, the Tessellator, has been configured, designed and is currently being built and integrated. Robot tasks include chemical injection and inspection of the shuttle's thermal protection system. This paper outlines tasks, rationale, and facility requirements for the development of this system. A detailed look at the mobile system and manipulator follow with a look at mechanics, electronics, and software. Salient features of the mobile robot include omnidirectionality, high reach, high stiffness and accuracy with safety and self-reliance integral to all aspects of the design. The robot system is shown to meet task, facility, and NASA requirements in its design resulting in unprecedented specifications for a mobile-manipulation system.
A mobile robot system for ground servicing operations on the space shuttle

NASA Technical Reports Server (NTRS)

Dowling, K.; Bennett, R.; Blackwell, M.; Graham, T.; Gatrall, S.; O'Toole, R.; Schempf, H.

1992-01-01

A mobile system for space shuttle servicing, the Tessellator, has been configured, designed and is currently being built and integrated. Robot tasks include chemical injection and inspection of the shuttle's thermal protection system. This paper outlines tasks, rationale, and facility requirements for the development of this system. A detailed look at the mobile system and manipulator follow with a look at mechanics, electronics, and software. Salient features of the mobile robot include omnidirectionality, high reach, high stiffness and accuracy with safety and self-reliance integral to all aspects of the design. The robot system is shown to meet task, facility, and NASA requirements in its design resulting in unprecedented specifications for a mobile-manipulation system.
Design and development of a mobile system for supporting emergency triage.

PubMed

Michalowski, W; Slowinski, R; Wilk, S; Farion, K J; Pike, J; Rubin, S

2005-01-01

Our objective was to design and develop a mobile clinical decision support system for emergency triage of different acute pain presentations. The system should interact with existing hospital information systems, run on mobile computing devices (handheld computers) and be suitable for operation in weak-connectivity conditions (with unstable connections between mobile clients and a server). The MET (Mobile Emergency Triage) system was designed following an extended client-server architecture. The client component, responsible for triage decision support, is built as a knowledge-based system, with domain ontology separated from generic problem solving methods and used for the automatic creation of a user interface. The MET system is well suited for operation in the Emergency Department of a hospital. The system's external interactions are managed by the server, while the MET clients, running on handheld computers are used by clinicians for collecting clinical data and supporting triage at the bedside. The functionality of the MET client is distributed into specialized modules, responsible for triaging specific types of acute pain presentations. The modules are stored on the server, and on request they can be transferred and executed on the mobile clients. The modular design provides for easy extension of the system's functionality. A clinical trial of the MET system validated the appropriateness of the system's design, and proved the usefulness and acceptance of the system in clinical practice. The MET system captures the necessary hospital data, allows for entry of patient information, and provides triage support. By operating on handheld computers, it fits into the regular emergency department workflow without introducing any hindrances or disruptions. It supports triage anytime and anywhere, directly at the point of care, and also can be used as an electronic patient chart, facilitating structured data collection.
The situation of waste mobile phone management in developed countries and development status in China.

PubMed

Xu, Chengjian; Zhang, Wenxuan; He, Wenzhi; Li, Guangming; Huang, Juwen

2016-12-01

With the rapid development of electronic industry and improvement of living standards, a large number of waste mobile phones were generated. According to statistics, approximately 400million waste mobile phones are generated each year in the world, and 25% of that are contributed by China. Irregular disposal of waste mobile phones will do great harm to environment and human health, while at the same time recycling of them has the potential for high profits. Given the enormous quantity, great harm and resource properties, developed countries have taken necessary measures to manage waste mobile phones. As the largest developing country, China has also set out to pay close attention to waste mobile phones. This paper reviewed the situation ofwaste mobile phone management in the developed countries, focused on the development of waste mobile phone management in China, and analyzed existing problems. In light of the successful experience of the developed countries, some suggestions were proposed to promote the waste mobile phone management in China and worked as a valuable reference for other countries. Copyright © 2016 Elsevier Ltd. All rights reserved.
The motion commotion: Human factors in transportation

NASA Technical Reports Server (NTRS)

Millar, A. E., Jr. (Editor); Rosen, R. L. (Editor); Gibson, J. D. (Editor); Crum, R. G. (Editor)

1972-01-01

The program for a systems approach to the problem of incorporating human factors in designing transportation systems is summarized. The importance of the human side of transportation is discussed along with the three major factors related to maintaining a mobile and quality life. These factors are (1) people, as individuals and groups, (2) society as a whole, and (3) the natural environment and man-made environs. The problems and bottlenecks are presented along with approaches to their solutions through systems analysis. Specific recommendations essential to achieving improved mobility within environmental constraints are presented.
Current problems in the theory of disordered semiconductors

DOE Office of Scientific and Technical Information (OSTI.GOV)

Bonch-Bruevich, V.L.

1987-05-01

This paper is an expanded version of a report read by the author at the 2nd All-Union Conference on Quantum chemistry of Solids (Riga, 1985) and at the 9th Session of Physics and Electronics (German Democratic Republic, Berlin, 1985). Three questions, which are under intensive discussion in the current literature, are examined: intermediate order in disordered semiconductors, the structure of the energy spectrum and wave functions near the mobility threshold, and the determination of the density of states in the mobility gap based on experimental data on the absorption of light.
Classification of Odours for Mobile Robots Using an Ensemble of Linear Classifiers

NASA Astrophysics Data System (ADS)

Trincavelli, Marco; Coradeschi, Silvia; Loutfi, Amy

2009-05-01

This paper investigates the classification of odours using an electronic nose mounted on a mobile robot. The samples are collected as the robot explores the environment. Under such conditions, the sensor response differs from typical three phase sampling processes. In this paper, we focus particularly on the classification problem and how it is influenced by the movement of the robot. To cope with these influences, an algorithm consisting of an ensemble of classifiers is presented. Experimental results show that this algorithm increases classification performance compared to other traditional classification methods.
On the ground-state degeneracy and entropy in a double-tetrahedral chain formed by the localized Ising spins and mobile electrons

NASA Astrophysics Data System (ADS)

Gálisová, Lucia

2018-05-01

Ground-state properties of a hybrid double-tetrahedral chain, in which the localized Ising spins regularly alternate with triangular plaquettes occupied by a variable number of mobile electrons, are exactly investigated. We demonstrate that the zero-temperature phase diagram of the model involves several non-degenerate, two-fold degenerate and macroscopically degenerate chiral phases. Low-temperature dependencies of the entropy and specific heat are also examined in order to gain a deeper insight into the degeneracy of individual ground-state phases and phase transitions. It is shown that a diversity of the ground-state degeneracy manifests itself in multiple-peak structures of both thermodynamic quantities. A remarkable temperature dependencies of the specific heat with two and three Schottky-type maxima are discussed in detail.
Review of electronic-nose technologies and algorithms to detect hazardous chemicals in the environment

Treesearch

Alphus D. Wilson

2012-01-01

Novel mobile electronic-nose (e-nose) devices and algorithms capable of real-time detection of industrial and municipal pollutants, released from point-sources, recently have been developed by scientists worldwide that are useful for monitoring specific environmental-pollutant levels for enforcement and implementation of effective pollution-abatement programs. E-nose...
METHODOLOGICAL ISSUES IN THE ANALYSIS OF RESIDENTIAL PREFERENCES, RESIDENTIAL MOBILITY, AND NEIGHBORHOOD CHANGE1

PubMed Central

Bruch, Elizabeth E.; Mare, Robert D.

2011-01-01

This paper reviews methods for analyzing both individual preferences and choices about where to live, and the implications of these choices for residential patterns. Although these methods are discussed in the context of residential choice, they can be applied more broadly to individual choices in a range of social contexts where behavior is interdependent. We review a variety of types of data on residential preferences and mobility and discuss appropriate statistical models for these data. We discuss the analysis of ranked and other types of clustered data; functional form issues; problems of unobserved heterogeneity in individuals and in neighborhoods; and strengths and weaknesses of stated preference data versus observations of actual mobility behavior. We also discuss specific problems with residential mobility data, including the treatment of one’s current location as a potential choice, how to specify the choice set of potential movers, the aggregation of units (such as dwelling units into neighborhoods) and the need to take account of variations in neighborhood size, the problem of very large choice sets and possible sampling solutions; and the link between residential mobility and patterns of neighborhood change. PMID:23476098
Submolecular Gates Self-Assemble for Hot-Electron Transfer in Proteins.

PubMed

Filip-Granit, Neta; Goldberg, Eran; Samish, Ilan; Ashur, Idan; van der Boom, Milko E; Cohen, Hagai; Scherz, Avigdor

2017-07-27

Redox reactions play key roles in fundamental biological processes. The related spatial organization of donors and acceptors is assumed to undergo evolutionary optimization facilitating charge mobilization within the relevant biological context. Experimental information from submolecular functional sites is needed to understand the organization strategies and driving forces involved in the self-development of structure-function relationships. Here we exploit chemically resolved electrical measurements (CREM) to probe the atom-specific electrostatic potentials (ESPs) in artificial arrays of bacteriochlorophyll (BChl) derivatives that provide model systems for photoexcited (hot) electron donation and withdrawal. On the basis of computations we show that native BChl's in the photosynthetic reaction center (RC) self-assemble at their ground-state as aligned gates for functional charge transfer. The combined computational and experimental results further reveal how site-specific polarizability perpendicular to the molecular plane enhances the hot-electron transport. Maximal transport efficiency is predicted for a specific, ∼5 Å, distance above the center of the metalized BChl, which is in remarkably close agreement with the distance and mutual orientation of corresponding native cofactors. These findings provide new metrics and guidelines for analysis of biological redox centers and for designing charge mobilizing machines such as artificial photosynthesis.
DOE Office of Scientific and Technical Information (OSTI.GOV)

Mikheev, Evgeny; Himmetoglu, Burak; Kajdos, Adam P.

We analyze and compare the temperature dependence of the electron mobility of two- and three-dimensional electron liquids in SrTiO{sub 3}. The contributions of electron-electron scattering must be taken into account to accurately describe the mobility in both cases. For uniformly doped, three-dimensional electron liquids, the room temperature mobility crosses over from longitudinal optical (LO) phonon-scattering-limited to electron-electron-scattering-limited as a function of carrier density. In high-density, two-dimensional electron liquids, LO phonon scattering is completely screened and the mobility is dominated by electron-electron scattering up to room temperature. The possible origins of the observed behavior and the consequences for approaches to improvemore » the mobility are discussed.« less
The Effectiveness of Mobile Phone Text Messaging in Improving Medication Adherence for Patients with Chronic Diseases: A Systematic Review.

PubMed

Ershad Sarabi, Roghayeh; Sadoughi, Farahnaz; Jamshidi Orak, Roohangiz; Bahaadinbeigy, Kambiz

2016-05-01

Medication non-adherence is a commonly observed problem in the self-administration of treatment, regardless of the disease type. Text messaging reminders, as electronic reminders, provide an opportunity to improve medication adherence. In this study, we aimed to provide evidence addressing the question of whether text message reminders were effective in improving patients' adherence to medication. We carried out a systematic literature search, using the five electronic bibliographic databases: PubMed, Embase, PsycINFO, CINAHL, and the Cochrane central register of controlled trials. Studies were included on the basis of whether they examined the benefits and effects of short-message service (SMS) interventions on medication adherence. The results of this systematic review indicated that text messaging interventions have improved patients' medication adherence rate (85%, 29.34). Included in the review, those who had problems with adherence, or those whom text messaging was most helpful had HIV, asthma, diabetes, schizophrenia and heart disease (73.5%). The period of intervention varied from 1 week to 14 months. The most common study design was randomized controlled trials (RCTs) (66%) carried out in the developed countries. This study demonstrated the potential of mobile phone text messaging for medication non-adherence problem solving.

Detection of prostate-specific antigen with biomolecule-gated AlGaN/GaN high electron mobility transistors

NASA Astrophysics Data System (ADS)

Li, Jia-dong; Cheng, Jun-jie; Miao, Bin; Wei, Xiao-wei; Xie, Jie; Zhang, Jin-cheng; Zhang, Zhi-qiang; Wu, Dong-min

2014-07-01

In order to improve the sensitivity of AlGaN/GaN high electron mobility transistor (HEMT) biosensors, a simple biomolecule-gated AlGaN/GaN HEMT structure was designed and successfully fabricated for prostate specific antigen (PSA) detection. UV/ozone was used to oxidize the GaN surface and then a 3-aminopropyl trimethoxysilane (APTES) self-assembled monolayer was bound to the sensing region. This monolayer serves as a binding layer for attachment of the prostate specific antibody (anti-PSA). The biomolecule-gated AlGaN/GaN HEMT sensor shows a rapid and sensitive response when the target prostate-specific antigen in buffer solution was added to the antibody-immobilized sensing area. The current change showed a logarithm relationship against the PSA concentration from 0.1 pg/ml to 0.993 ng/ml. The sensitivity of 0.215% is determined for 0.1 pg/ml PSA solution. The above experimental result of the biomolecule-gated AlGaN/GaN HEMT biosensor suggested that this biosensor might be a useful tool for prostate cancer screening.
Mobile technology supporting trainee doctors' workplace learning and patient care: an evaluation.

PubMed

Hardyman, Wendy; Bullock, Alison; Brown, Alice; Carter-Ingram, Sophie; Stacey, Mark

2013-01-21

The amount of information needed by doctors has exploded. The nature of knowledge (explicit and tacit) and processes of knowledge acquisition and participation are complex. Aiming to assist workplace learning, Wales Deanery funded "iDoc", a project offering trainee doctors a Smartphone library of medical textbooks. Data on trainee doctors' (Foundation Year 2) workplace information seeking practice was collected by questionnaire in 2011 (n = 260). iDoc baseline questionnaires (n = 193) collected data on Smartphone usage alongside other workplace information sources. Case reports (n = 117) detail specific instances of Smartphone use. Most frequently (daily) used information sources in the workplace: senior medical staff (80% F2 survey; 79% iDoc baseline); peers (70%; 58%); and other medical/nursing team staff (53% both datasets). Smartphones were used more frequently by males (p < 0.01). Foundation Year 1 (newly qualified) was judged the most useful time to have a Smartphone library because of increased responsibility and lack of knowledge/experience.Preferred information source varied by question type: hard copy texts for information-based questions; varied resources for skills queries; and seniors for more complex problems. Case reports showed mobile technology used for simple (information-based), complex (problem-based) clinical questions and clinical procedures (skills-based scenarios). From thematic analysis, the Smartphone library assisted: teaching and learning from observation; transition from medical student to new doctor; trainee doctors' discussions with seniors; independent practice; patient care; and this 'just-in-time' access to reliable information supported confident and efficient decision-making. A variety of information sources are used regularly in the workplace. Colleagues are used daily but seniors are not always available. During transitions, constant access to the electronic library was valued. It helped prepare trainee doctors for discussions with their seniors, assisting the interchange between explicit and tacit knowledge.By supporting accurate prescribing and treatment planning, the electronic library contributed to enhanced patient care. Trainees were more rapidly able to medicate patients to reduce pain and more quickly call for specific assessments. However, clinical decision-making often requires dialogue: what Smartphone technology can do is augment, not replace, discussion with their colleagues in the community of practice.
VOP memory management in MPEG-4

NASA Astrophysics Data System (ADS)

Vaithianathan, Karthikeyan; Panchanathan, Sethuraman

2001-03-01

MPEG-4 is a multimedia standard that requires Video Object Planes (VOPs). Generation of VOPs for any kind of video sequence is still a challenging problem that largely remains unsolved. Nevertheless, if this problem is treated by imposing certain constraints, solutions for specific application domains can be found. MPEG-4 applications in mobile devices is one such domain where the opposite goals namely low power and high throughput are required to be met. Efficient memory management plays a major role in reducing the power consumption. Specifically, efficient memory management for VOPs is difficult because the lifetimes of these objects vary and these life times may be overlapping. Varying life times of the objects requires dynamic memory management where memory fragmentation is a key problem that needs to be addressed. In general, memory management systems address this problem by following a combination of strategy, policy and mechanism. For MPEG4 based mobile devices that lack instruction processors, a hardware based memory management solution is necessary. In MPEG4 based mobile devices that have a RISC processor, using a Real time operating system (RTOS) for this memory management task is not expected to be efficient because the strategies and policies used by the ROTS is often tuned for handling memory segments of smaller sizes compared to object sizes. Hence, a memory management scheme specifically tuned for VOPs is important. In this paper, different strategies, policies and mechanisms for memory management are considered and an efficient combination is proposed for the case of VOP memory management along with a hardware architecture, which can handle the proposed combination.
77 FR 18860 - Certain Consumer Electronics, Including Mobile Phones and Tablets; Notice of Receipt of Complaint...

Federal Register 2010, 2011, 2012, 2013, 2014

2012-03-28

... INTERNATIONAL TRADE COMMISSION [DN 2885] Certain Consumer Electronics, Including Mobile Phones and.... International Trade Commission has received a complaint entitled Certain Consumer Electronics, Including Mobile... electronics, including mobile phones and tablets. The complaint names as respondents ASUSTeK Computer, Inc. of...
The role of polarization coulomb field scattering in the electron mobility of AlGaN/AlN/GaN heterostructure field-effect transistors

NASA Astrophysics Data System (ADS)

Liu, Yan; Lin, Zhaojun; Zhao, Jingtao; Yang, Ming; Shi, Wenjing; Lv, Yuanjie; Feng, Zhihong

2016-04-01

The electron mobility for the prepared AlGaN/AlN/GaN heterostructure field-effect transistor (HFET) with the ratio of the gate length to the drain-to-source distance being less than 1/2 has been studied by comparing the measured electron mobility with the theoretical value. The measured electron mobility is derived from the measured capacitance-voltage (C-V) and current-voltage (I-V) characteristics, and the theoretical mobility is determined by using Matthiessen's law, involving six kinds of important scattering mechanisms. For the prepared device at room temperature, longitudinal optical phonon scattering (LO scattering) was found to have a remarkable effect on the value of the electron mobility, and polarization Coulomb field scattering (PCF scattering ) was found to be important to the changing trend of the electron mobility versus the two-dimensional electron gas (2DEG) density.
High Performance 50 nm InAlAs/In0.75GaAs Metamorphic High Electron Mobility Transistors with Si3N4 Passivation on Thin InGaAs Layer

NASA Astrophysics Data System (ADS)

Yeon, Seongjin; Seo, Kwangseok

2008-04-01

We fabricated 50 nm InAlAs/InGaAs metamorphic high electron mobility transistors (HEMTs) with a very thin barrier. Through the reduction of the gate-channel distance (dGC) in the epitaxial structure, a channel aspect ratio (ARC) of over three was achieved when Lg was 50 nm. We inserted a thin InGaAs layer as a protective layer, and tested various gate structures to reduce surface problems induced by barrier shrinkage and to optimize the device characteristics. Through the optimization of the gate structure with the thin InGaAs layer, the fabricated 50 nm metamorphic HEMT exhibited high DC and RF characteristics, Gm of 1.5 S/mm, and fT of 490 GHz.
Do surveys with paper and electronic devices differ in quality and cost? Experience from the Rufiji Health and demographic surveillance system in Tanzania.

PubMed

Mukasa, Oscar; Mushi, Hildegalda P; Maire, Nicolas; Ross, Amanda; de Savigny, Don

2017-01-01

Data entry at the point of collection using mobile electronic devices may make data-handling processes more efficient and cost-effective, but there is little literature to document and quantify gains, especially for longitudinal surveillance systems. To examine the potential of mobile electronic devices compared with paper-based tools in health data collection. Using data from 961 households from the Rufiji Household and Demographic Survey in Tanzania, the quality and costs of data collected on paper forms and electronic devices were compared. We also documented, using qualitative approaches, field workers, whom we called 'enumerators', and households' members on the use of both methods. Existing administrative records were combined with logistics expenditure measured directly from comparison households to approximate annual costs per 1,000 households surveyed. Errors were detected in 17% (166) of households for the paper records and 2% (15) for the electronic records (p < 0.001). There were differences in the types of errors (p = 0.03). Of the errors occurring, a higher proportion were due to accuracy in paper surveys (79%, 95% CI: 72%, 86%) compared with electronic surveys (58%, 95% CI: 29%, 87%). Errors in electronic surveys were more likely to be related to completeness (32%, 95% CI 12%, 56%) than in paper surveys (11%, 95% CI: 7%, 17%).The median duration of the interviews ('enumeration'), per household was 9.4 minutes (90% central range 6.4, 12.2) for paper and 8.3 (6.1, 12.0) for electronic surveys (p = 0.001). Surveys using electronic tools, compared with paper-based tools, were less costly by 28% for recurrent and 19% for total costs. Although there were technical problems with electronic devices, there was good acceptance of both methods by enumerators and members of the community. Our findings support the use of mobile electronic devices for large-scale longitudinal surveys in resource-limited settings.
Electronic Spin Storage in an Electrically Readable Nuclear Spin Memory with a Lifetime >100 Seconds

NASA Astrophysics Data System (ADS)

McCamey, D. R.; Van Tol, J.; Morley, G. W.; Boehme, C.

2010-12-01

Electron spins are strong candidates with which to implement spintronics because they are both mobile and able to be manipulated. The relatively short lifetimes of electron spins, however, present a problem for the long-term storage of spin information. We demonstrated an ensemble nuclear spin memory in phosphorous-doped silicon, which can be read out electrically and has a lifetime exceeding 100 seconds. The electronic spin information can be mapped onto and stored in the nuclear spin of the phosphorus donors, and the nuclear spins can then be repetitively read out electrically for time periods that exceed the electron spin lifetime. We discuss how this memory can be used in conjunction with other silicon spintronic devices.
Higher Education Students’ Behaviour to Adopt Mobile Learning

NASA Astrophysics Data System (ADS)

Batmetan, J. R.; Palilingan, V. R.

2018-02-01

Mobile phone is an electronic device most often used by Y generation in Indonesia. This ages have become an important part in the growth of higher education in this country. The problem raised in this study is that very few students in higher education are adopting and accessing digital learning content using mobile phones. The objective of this study is to investigate the higher education students’ behaviour in using mobile learning. The research method used is Structural equation models (SEM) method to analyse the factors that influence higher education students’ behaviour in using mobile learning. The results of this study indicate tends of this student 85% to keep internet access in privacy. The majority of respondent is 78% having behaviour to keep adopting mobile learning and still use it in the future. Why? because this study shows that on the level of usability, easy to use, easy to learn, in various devices have a significant effect on the level of adoption of mobile learning. Implication of this study is higher education students’ behaviour of especially Y generation tends to prioritize the usability towards mobile learning and will continue to adopt mobile learning in the future.
76 FR 24051 - In the Matter of Certain Electronic Devices, Including Mobile Phones, Mobile Tablets, Portable...

Federal Register 2010, 2011, 2012, 2013, 2014

2011-04-29

..., Including Mobile Phones, Mobile Tablets, Portable Music Players, and Computers, and Components Thereof... certain electronic devices, including mobile phones, mobile tablets, portable music players, and computers... mobile phones, mobile tablets, portable music players, and computers, and components thereof that...
Electron mobility in monoclinic β-Ga2O3—Effect of plasmon-phonon coupling, anisotropy, and confinement

NASA Astrophysics Data System (ADS)

Ghosh, Krishnendu; Singisetti, Uttam

2017-11-01

This work reports an investigation of electron transport in monoclinic \\beta-Ga2O3 based on a combination of density functional perturbation theory based lattice dynamical computations, coupling calculation of lattice modes with collective plasmon oscillations and Boltzmann theory based transport calculations. The strong entanglement of the plasmon with the different longitudinal optical (LO) modes make the role LO-plasmon coupling crucial for transport. The electron density dependence of the electron mobility in \\beta-Ga2O3 is studied in bulk material form and also in the form of two-dimensional electron gas. Under high electron density a bulk mobility of 182 cm2/ V.s is predicted while in 2DEG form the corresponding mobility is about 418 cm2/V.s when remote impurities are present at the interface and improves further as the remote impurity center moves away from the interface. The trend of the electron mobility shows promise for realizing high electron mobility in dopant isolated electron channels. The experimentally observed small anisotropy in mobility is traced through a transient Monte Carlo simulation. It is found that the anisotropy of the IR active phonon modes is responsible for giving rise to the anisotropy in low-field electron mobility.
Assistive devices for balance and mobility: benefits, demands, and adverse consequences.

PubMed

Bateni, Hamid; Maki, Brian E

2005-01-01

To provide information on the advantages and possible disadvantages of using canes and walkers. English-language articles were identified by searching MEDLINE and PubMed (1966-May 2003) for key words cane or walker , excluding articles unrelated to mobility aids. Bibliographies were reviewed and ISI Web of Science citation searches were run to identify additional references. Over 1000 articles were selected for further evaluation. We extracted all studies of single-tip canes or pickup walkers addressing: (1) functional, biomechanic, or neuromotor benefits; (2) biomechanic, attentional, neuromotor, metabolic, or physiologic demands; and (3) falls, injuries, or other problems. We included approximately 10% of the articles originally identified. The methodology of each selected article, and findings relevant to the benefits, demands, or adverse effects of cane or walker use were summarized. Findings were synthesized by considering their relation to basic biomechanic principles. Some biomechanic findings appear to support the clinical view that canes and walkers can improve balance and mobility for older adults and people with other clinical conditions. However, a large proportion of users experience difficulties, and the use of such devices is associated with increased risk of falling. A small number of studies have characterized some of the specific demands and problems associated with using mobility aids. Clinical and biomechanic evaluations of canes and walkers confirm that these devices can improve balance and mobility. However, they can also interfere with ones ability to maintain balance in certain situations, and the strength and metabolic demands can be excessive. More research is needed to identify and solve specific problems. Such research may lead to improved designs and guidelines for safer use of canes and walkers.
Fast detection of toxic industrial compounds by laser ion mobility spectrometry

NASA Astrophysics Data System (ADS)

Oberhuettinger, Carola; Langmeier, Andreas; Oberpriller, Helmut; Kessler, Matthias; Goebel, Johann; Mueller, Gerhard

2009-05-01

Trace detection of toxic industrial compounds has been investigated with the help of a laser ion mobility spectrometer (LIMS). The LIMS was equipped with a tuneable UV laser source for enabling two-photon ionization of the analyte gases and an ion drift tube for the measurement of the ion mobility. Different aromatic and aliphatic hydrocarbons as well as amines were investigated. We find that the first class of molecules can be well ionized due to the delocalization of their valence electron shells and the second due to the presence of non-bonding electrons in lone-pair orbitals. Selectivity of detection is attained on the basis of molecule-specific photo-ionization and drift time spectra. Ion currents were found to scale linearly with the substance concentration over several orders of magnitude down to the detection limits in the ppt range. As besides toxic industrial compounds, similar electron configurations also occur in illicit drugs, toxins and pharmaceutical substances, LIMS can be applied in a variety of fields ranging from environmental analysis, air pollution monitoring, drug detection and chemical process monitoring.
Description of a Mobile-based Electronic Informed Consent System Development.

PubMed

Hwang, Min-A; Kwak, In Ja

2015-01-01

Seoul National University Hospital constructed and implemented a computer-based informed consent system in December 2011. As of 2013, 30% of the informed consents were still filled out manually on paper. Patients and medical staff continuously suggested the implementation of a system for electronic informed consent using portable devices. Therefore, a mobile-based system for electronic informed consent was developed in 2013 to prevent the issues that arise with computer-based systems and paper informed consent. The rate of filling out electronic informed consent increased from 69% to 95% following the implementation of the mobile-based electronic informed consent. This construction of a mobile-based electronic informed consent system would be a good reference point for the development of a mobile-based Electronic Medical Record and for various mobile system environments in medical institutions.
[Conduct of survey four months after the start of EMR for home visits to promote cooperation between hospitals and clinics].

PubMed

Nakagawa, Yumiko; Sawada, Sachiko; Tomiyama, Takashi; Ueda, Yuki; Fujii, Kou; Takeshita, Kiyotaka; Kobayashi, Mitsuru; Isono, Osamu

2014-12-01

Electronic medical records(EMR)for home visits were introduced in October 2013 at our institution in order to ensure smooth cooperation between the hospital and clinic by sharing the details of a patient's medical record. A system was developed for remote desktop connections to the EMR terminal server(virtual server)with the use of an SSL-VPN. Mobile terminals and mobile printers were used. Four months after the start of this system, a survey was conducted for 41 home care professionals and other staff(physicians, nurses, and office staff). Home care staff indicated that they had problems with the system, including bad connections and operating conditions, and difficulties responding to problems when they arose. Other staff indicated that they were able to acquire patient information faster than with paper-based records. Future issues include improvements to the user-friendliness of the terminals and improved responses to problems when they occur.
Requirements' Role in Mobilizing and Enabling Design Conversation

NASA Astrophysics Data System (ADS)

Bergman, Mark

Requirements play a critical role in a design conversation of systems and products. Product and system design exists at the crossroads of problems, solutions and requirements. Requirements contextualize problems and solutions, pointing the way to feasible outcomes. These are captured with models and detailed specifications. Still, stakeholders need to be able to understand one-another using shared design representations in order to mobilize bias and transform knowledge towards legitimized, desired results. Many modern modeling languages, including UML, as well as detailed, logic-based specifications are beyond the comprehension of key stakeholders. Hence, they inhibit, rather than promote design conversation. Improved design boundary objects (DBO), especially design requirements boundary objects (DRBO), need to be created and refined to improve the communications between principals. Four key features of design boundary objects that improve and promote design conversation are discussed in detail. A systems analysis and design case study is presented which demonstrates these features in action. It describes how a small team of analysts worked with key stakeholders to mobilize and guide a complex system design discussion towards an unexpected, yet desired outcome within a short time frame.
Adolescent behavior and achievement, social capital, and the timing of geographic mobility.

PubMed

Gillespie, Brian Joseph

2013-09-01

This paper examines the relationship between geographic mobility and adolescent academic achievement and behavior problems. Specifically, it addresses how the effects of moving differ by age and how social capital moderates the impact of moving on children (aged 6 to 15). Children's behavior problems and academic achievement test scores were compared across four survey waves of the National Longitudinal Survey of Youth (2000, 2002, 2004, and 2006) and matched to data from their mothers' reports from the National Longitudinal Survey of Youth 1979. The findings indicate that the negative behavioral effects of geographic mobility on adolescents are most pronounced for individuals relocating to a new city, county, or state as opposed to those moving locally (i.e., within the same city). Furthermore, as suggested by a life-course perspective, the negative effects of moving on behavior problems decrease as children get older. The results also show that several social capital factors moderate the effects of moving on behavior but not achievement. Copyright © 2013 Elsevier Ltd. All rights reserved.
Human mobility: Models and applications

NASA Astrophysics Data System (ADS)

Barbosa, Hugo; Barthelemy, Marc; Ghoshal, Gourab; James, Charlotte R.; Lenormand, Maxime; Louail, Thomas; Menezes, Ronaldo; Ramasco, José J.; Simini, Filippo; Tomasini, Marcello

2018-03-01

Recent years have witnessed an explosion of extensive geolocated datasets related to human movement, enabling scientists to quantitatively study individual and collective mobility patterns, and to generate models that can capture and reproduce the spatiotemporal structures and regularities in human trajectories. The study of human mobility is especially important for applications such as estimating migratory flows, traffic forecasting, urban planning, and epidemic modeling. In this survey, we review the approaches developed to reproduce various mobility patterns, with the main focus on recent developments. This review can be used both as an introduction to the fundamental modeling principles of human mobility, and as a collection of technical methods applicable to specific mobility-related problems. The review organizes the subject by differentiating between individual and population mobility and also between short-range and long-range mobility. Throughout the text the description of the theory is intertwined with real-world applications.
Academic Misconduct: An Investigation into Male Students' Perceptions, Experiences & Attitudes towards Cheating and Plagiarism in a Middle Eastern University Context

ERIC Educational Resources Information Center

Tayan, Bilal M.

2017-01-01

Academic misconduct in many educational institutions in the Middle East is an inherent problem. This has been particularly true amongst the university student population. The proliferation of the Internet and the ownership of mobile and electronic devices, have, in part, witnessed rates of cheating, plagiarism and academic misconduct cases…
A global approach to kinematic path planning to robots with holonomic and nonholonomic constraints

NASA Technical Reports Server (NTRS)

Divelbiss, Adam; Seereeram, Sanjeev; Wen, John T.

1993-01-01

Robots in applications may be subject to holonomic or nonholonomic constraints. Examples of holonomic constraints include a manipulator constrained through the contact with the environment, e.g., inserting a part, turning a crank, etc., and multiple manipulators constrained through a common payload. Examples of nonholonomic constraints include no-slip constraints on mobile robot wheels, local normal rotation constraints for soft finger and rolling contacts in grasping, and conservation of angular momentum of in-orbit space robots. The above examples all involve equality constraints; in applications, there are usually additional inequality constraints such as robot joint limits, self collision and environment collision avoidance constraints, steering angle constraints in mobile robots, etc. The problem of finding a kinematically feasible path that satisfies a given set of holonomic and nonholonomic constraints, of both equality and inequality types is addressed. The path planning problem is first posed as a finite time nonlinear control problem. This problem is subsequently transformed to a static root finding problem in an augmented space which can then be iteratively solved. The algorithm has shown promising results in planning feasible paths for redundant arms satisfying Cartesian path following and goal endpoint specifications, and mobile vehicles with multiple trailers. In contrast to local approaches, this algorithm is less prone to problems such as singularities and local minima.

Dosimetric characteristics of electron beams produced by a mobile accelerator for IORT.

PubMed

Pimpinella, M; Mihailescu, D; Guerra, A S; Laitano, R F

2007-10-21

Energy and angular distributions of electron beams with different energies were simulated by Monte Carlo calculations. These beams were generated by the NOVAC7 system (Hitesys, Italy), a mobile electron accelerator specifically dedicated to intra-operative radiation therapy (IORT). The electron beam simulations were verified by comparing the measured dose distributions with the corresponding calculated distributions. As expected, a considerable difference was observed in the energy and angular distributions between the IORT beams studied in the present work and the electron beams produced by conventional accelerators for non-IORT applications. It was also found that significant differences exist between the IORT beams used in this work and other IORT beams with different collimation systems. For example, the contribution from the scattered electrons to the total dose was found to be up to 15% higher in the NOVAC7 beams. The water-to-air stopping power ratios of the IORT beams used in this work were calculated on the basis of the beam energy distributions obtained by the Monte Carlo simulations. These calculated stopping power ratios, s(w,air), were compared with the corresponding s(w,air) values recommended by the TRS-381 and TRS-398 IAEA dosimetry protocols in order to estimate the deviations between a dosimetry based on generic parameters and a dosimetry based on parameters specifically obtained for the actual IORT beams. The deviations in the s(w,air) values were found to be as large as up to about 1%. Therefore, we recommend that a preliminary analysis should always be made when dealing with IORT beams in order to assess to what extent the possible differences in the s(w,air) values have to be accounted for or may be neglected on the basis of the specific accuracy needed in clinical dosimetry.
Electron drift velocity and mobility in graphene

NASA Astrophysics Data System (ADS)

Dong, Hai-Ming; Duan, Yi-Feng; Huang, Fei; Liu, Jin-Long

2018-04-01

We present a theoretical study of the electric transport properties of graphene-substrate systems. The drift velocity, mobility, and temperature of the electrons are self-consistently determined using the Boltzmann equilibrium equations. It is revealed that the electronic transport exhibits a distinctly nonlinear behavior. A very high mobility is achieved with the increase of the electric fields increase. The electron velocity is not completely saturated with the increase of the electric field. The temperature of the hot electrons depends quasi-linearly on the electric field. In addition, we show that the electron velocity, mobility, and electron temperature are sensitive to the electron density. These findings could be employed for the application of graphene for high-field nano-electronic devices.
Contact Resistance and Channel Conductance of Graphene Field-Effect Transistors under Low-Energy Electron Irradiation

PubMed Central

Giubileo, Filippo; Di Bartolomeo, Antonio; Martucciello, Nadia; Romeo, Francesco; Iemmo, Laura; Romano, Paola; Passacantando, Maurizio

2016-01-01

We studied the effects of low-energy electron beam irradiation up to 10 keV on graphene-based field effect transistors. We fabricated metallic bilayer electrodes to contact mono- and bi-layer graphene flakes on SiO2, obtaining specific contact resistivity ρc≈19 kΩ·µm2 and carrier mobility as high as 4000 cm2·V−1·s−1. By using a highly doped p-Si/SiO2 substrate as the back gate, we analyzed the transport properties of the device and the dependence on the pressure and on the electron bombardment. We demonstrate herein that low energy irradiation is detrimental to the transistor current capability, resulting in an increase in contact resistance and a reduction in carrier mobility, even at electron doses as low as 30 e−/nm2. We also show that irradiated devices recover their pristine state after few repeated electrical measurements. PMID:28335335
High-mobility hydrogen-terminated Si(111) transistors for measurement of six-fold valley degenerate two-dimensional electron systems in fractional quantum Hall regime

NASA Astrophysics Data System (ADS)

Hu, Binhui; Yazdanpanah, Mohamad Meqdad; Kane, Bruce E.

2015-03-01

The quality of hydrogen-terminated Si(111) (H-Si(111)) transistors has improved significantly. Peak electron mobility of 325,000 cm2/Vs was achieved at 90 mK, and the fractional quantum Hall effect (FQHE) at 1 < ν < 2 was studied extensively. We have further improved the device by solving gate leakage and contact problems with an updated design, in which a Si piece with thermal oxide acts as a gate through a vacuum cavity, and PN junctions are used to define a hexagonal two-dimensional (2D) region on a H-Si(111) piece. The device operates as an ambipolar transistor, in which a 2D electron system (2DES) and a 2D hole system can be induced at the same H-Si(111) surface. Peak electron mobility of more than 200,000 cm2/Vs is routinely achieved at 300 mK. The Si(111) surface has a six-fold valley degeneracy. The hexagonal device is designed to investigate the symmetry of the 2DES. Preliminary data show that the transport anisotropy at ν < 6 can be explained by the valley occupancy. The details of the valley occupancy can be caused by several mechanisms, such as miscut, magnetic field, pseudospin quantum Hall ferromagnetism (QHFM), and nematic valley polarization phases. The FQHE is investigated in magnetic fields up to 35T, and the properties of composite fermions will be discussed.
78 FR 23593 - Certain Mobile Electronic Devices Incorporating Haptics; Termination of Investigation

Federal Register 2010, 2011, 2012, 2013, 2014

2013-04-19

... INTERNATIONAL TRADE COMMISSION [Investigation No. 337-TA-834] Certain Mobile Electronic Devices... this investigation may be viewed on the Commission's electronic docket (EDIS) at http://edis.usitc.gov... mobile electronic devices incorporating haptics that infringe certain claims of six Immersion patents. 77...
Exploring the Use of Electronic Mobile Technologies among Distance Learners in Rural Communities for Safe and Disruptive Learning

ERIC Educational Resources Information Center

Ntloedibe-Kuswani, Gomang Seratwa

2013-01-01

Several studies indicated the potential of electronic mobile technologies in reaching (safe learning) under-served communities and engaging (disruptive learning) disadvantaged peoples affording them learning experiences. However, the potential benefits of (electronic mobile learning) e-mobile learning have not been well understood from the…
Machine vision and appearance based learning

NASA Astrophysics Data System (ADS)

Bernstein, Alexander

2017-03-01

Smart algorithms are used in Machine vision to organize or extract high-level information from the available data. The resulted high-level understanding the content of images received from certain visual sensing system and belonged to an appearance space can be only a key first step in solving various specific tasks such as mobile robot navigation in uncertain environments, road detection in autonomous driving systems, etc. Appearance-based learning has become very popular in the field of machine vision. In general, the appearance of a scene is a function of the scene content, the lighting conditions, and the camera position. Mobile robots localization problem in machine learning framework via appearance space analysis is considered. This problem is reduced to certain regression on an appearance manifold problem, and newly regression on manifolds methods are used for its solution.
Fast words boundaries localization in text fields for low quality document images

NASA Astrophysics Data System (ADS)

Ilin, Dmitry; Novikov, Dmitriy; Polevoy, Dmitry; Nikolaev, Dmitry

2018-04-01

The paper examines the problem of word boundaries precise localization in document text zones. Document processing on a mobile device consists of document localization, perspective correction, localization of individual fields, finding words in separate zones, segmentation and recognition. While capturing an image with a mobile digital camera under uncontrolled capturing conditions, digital noise, perspective distortions or glares may occur. Further document processing gets complicated because of its specifics: layout elements, complex background, static text, document security elements, variety of text fonts. However, the problem of word boundaries localization has to be solved at runtime on mobile CPU with limited computing capabilities under specified restrictions. At the moment, there are several groups of methods optimized for different conditions. Methods for the scanned printed text are quick but limited only for images of high quality. Methods for text in the wild have an excessively high computational complexity, thus, are hardly suitable for running on mobile devices as part of the mobile document recognition system. The method presented in this paper solves a more specialized problem than the task of finding text on natural images. It uses local features, a sliding window and a lightweight neural network in order to achieve an optimal algorithm speed-precision ratio. The duration of the algorithm is 12 ms per field running on an ARM processor of a mobile device. The error rate for boundaries localization on a test sample of 8000 fields is 0.3
Enhancing the electron mobility of SrTiO3 with strain

NASA Astrophysics Data System (ADS)

Jalan, Bharat; Allen, S. James; Beltz, Glenn E.; Moetakef, Pouya; Stemmer, Susanne

2011-03-01

We demonstrate, using high-mobility SrTiO3 thin films grown by molecular beam epitaxy, that stress has a pronounced influence on the electron mobility in this prototype complex oxide. Moderate strains result in more than 300% increases in the electron mobilities with values exceeding 120 000 cm2/V s and no apparent saturation in the mobility gains. The results point to a range of opportunities to tailor high-mobility oxide heterostructure properties and open up ways to explore oxide physics.
76 FR 41522 - In the Matter of Certain Electronic Devices, Including Mobile Phones, Mobile Tablets, Portable...

Federal Register 2010, 2011, 2012, 2013, 2014

2011-07-14

... INTERNATIONAL TRADE COMMISSION [Investigation No. 337-TA-771] In the Matter of Certain Electronic Devices, Including Mobile Phones, Mobile Tablets, Portable Music Players, and Computers, and Components... certain mobile phones, mobile tablets, portable music players, and computers. 76 FR 24051 (Apr. 29, 2011...
Nomadism as a Man-Environment System

ERIC Educational Resources Information Center

Rapoport, Amos

1978-01-01

Concepts derived from general man-environment system (MES) models are applied to the specific problem of nomadic sedentarization. The analysis focuses on the manner in which residential mobility may function as a central element in nomadic cultures. (Author/MA)
Adaptive tracking control of a wheeled mobile robot via an uncalibrated camera system.

PubMed

Dixon, W E; Dawson, D M; Zergeroglu, E; Behal, A

2001-01-01

This paper considers the problem of position/orientation tracking control of wheeled mobile robots via visual servoing in the presence of parametric uncertainty associated with the mechanical dynamics and the camera system. Specifically, we design an adaptive controller that compensates for uncertain camera and mechanical parameters and ensures global asymptotic position/orientation tracking. Simulation and experimental results are included to illustrate the performance of the control law.
Understanding Local and Macroscopic Electron Mobilities in the Fullerene Network of Conjugated Polymer-based Solar Cells. Time-Resolved Microwave Conductivity and Theory

DOE Office of Scientific and Technical Information (OSTI.GOV)

Aguirre, Jordan C.; Arntsen, Christopher D.; Hernandez, Samuel

2013-09-23

The efficiency of bulk heterojunction (BHJ) organic photovoltaics is sensitive to the morphology of the fullerene network that transports electrons through the device. This sensitivity makes it difficult to distinguish the contrasting roles of local electron mobility (how easily electrons can transfer between neighboring fullerene molecules) and macroscopic electron mobility (how well-connected is the fullerene network on device length scales) in solar cell performance. In this work, a combination of density functional theory (DFT) calculations, flash-photolysis time-resolved microwave conductivity (TRMC) experiments, and space-charge-limit current (SCLC) mobility estimates are used to examine the roles of local and macroscopic electron mobility inmore » conjugated polymer/fullerene BHJ photovoltaics. The local mobility of different pentaaryl fullerene derivatives (so-called ‘shuttlecock’ molecules) is similar, so that differences in solar cell efficiency and SCLC mobilities result directly from the different propensities of these molecules to self-assemble on macroscopic length scales. These experiments and calculations also demonstrate that the local mobility of phenyl-C60 butyl methyl ester (PCBM) is an order of magnitude higher than that of other fullerene derivatives, explaining why PCBM has been the acceptor of choice for conjugated polymer BHJ devices even though it does not form an optimal macroscopic network. The DFT calculations indicate that PCBM's superior local mobility comes from the near-spherical nature of its molecular orbitals, which allow strong electronic coupling between adjacent molecules. In combination, DFT and TRMC techniques provide a tool for screening new fullerene derivatives for good local mobility when designing new molecules that can improve on the macroscopic electron mobility offered by PCBM.« less
Motion Trajectories for Wide-area Surveying with a Rover-based Distributed Spectrometer

NASA Technical Reports Server (NTRS)

Tunstel, Edward; Anderson, Gary; Wilson, Edmond

2006-01-01

A mobile ground survey application that employs remote sensing as a primary means of area coverage is highlighted. It is distinguished from mobile robotic area coverage problems that employ contact or proximity-based sensing. The focus is on a specific concept for performing mobile surveys in search of biogenic gases on planetary surfaces using a distributed spectrometer -- a rover-based instrument designed for wide measurement coverage of promising search areas. Navigation algorithms for executing circular and spiral survey trajectories are presented for widearea distributed spectroscopy and evaluated based on area covered and distance traveled.
Electron mobility of two-dimensional electron gas in InGaN heterostructures: Effects of alloy disorder and random dipole scatterings

NASA Astrophysics Data System (ADS)

Hoshino, Tomoki; Mori, Nobuya

2018-04-01

InGaN has a smaller electron effective mass and is expected to be used as a channel material for high-electron-mobility transistors. However, it is an alloy semiconductor with a random distribution of atoms, which introduces additional scattering mechanisms: alloy disorder and random dipole scatterings. In this work, we calculate the electron mobility in InGaN- and GaN-channel high-electron-mobility transistors (HEMTs) while taking into account acoustic deformation potential, polar optical phonon, alloy disorder, and random dipole scatterings. For InGaN-channel HEMTs, we find that not only alloy disorder but also random dipole scattering has a strong impact on the electron mobility and it significantly decreases as the In mole fraction of the channel increases. Our calculation also shows that the channel thickness w dependence of the mobility is rather weak when w > 1 nm for In0.1Ga0.9N-channel HEMTs.
Balanced Ambipolar Organic Field-Effect Transistors by Polymer Preaggregation.

PubMed

Janasz, Lukasz; Luczak, Adam; Marszalek, Tomasz; Dupont, Bertrand G R; Jung, Jaroslaw; Ulanski, Jacek; Pisula, Wojciech

2017-06-21

Ambipolar organic field-effect transistors (OFETs) based on heterojunction active films still suffer from an imbalance in the transport of electrons and holes. This problem is related to an uncontrolled phase separation between the donor and acceptor organic semiconductors in the thin films. In this work, we have developed a concept to improve the phase separation in heterojunction transistors to enhance their ambipolar performance. This concept is based on preaggregation of the donor polymer, in this case poly(3-hexylthiophene) (P3HT), before solution mixing with the small-molecular-weight acceptor, phenyl-C61-butyric acid methyl ester (PCBM). The resulting heterojunction transistor morphology consists of self-assembled P3HT fibers embedded in a PCBM matrix, ensuring balanced mobilities reaching 0.01 cm 2 /V s for both holes and electrons. These are the highest mobility values reported so far for ambipolar OFETs based on P3HT/PCBM blends. Preaggregation of the conjugated polymer before fabricating binary blends can be regarded as a general concept for a wider range of semiconducting systems applicable in organic electronic devices.
Meeting the challenges of installing a mobile robotic system

NASA Technical Reports Server (NTRS)

Decorte, Celeste

1994-01-01

The challenges of integrating a mobile robotic system into an application environment are many. Most problems inherent to installing the mobile robotic system fall into one of three categories: (1) the physical environment - location(s) where, and conditions under which, the mobile robotic system will work; (2) the technological environment - external equipment with which the mobile robotic system will interact; and (3) the human environment - personnel who will operate and interact with the mobile robotic system. The successful integration of a mobile robotic system into these three types of application environment requires more than a good pair of pliers. The tools for this job include: careful planning, accurate measurement data (as-built drawings), complete technical data of systems to be interfaced, sufficient time and attention of key personnel for training on how to operate and program the robot, on-site access during installation, and a thorough understanding and appreciation - by all concerned - of the mobile robotic system's role in the security mission at the site, as well as the machine's capabilities and limitations. Patience, luck, and a sense of humor are also useful tools to keep handy during a mobile robotic system installation. This paper will discuss some specific examples of problems in each of three categories, and explore approaches to solving these problems. The discussion will draw from the author's experience with on-site installations of mobile robotic systems in various applications. Most of the information discussed in this paper has come directly from knowledge learned during installations of Cybermotion's SR2 security robots. A large part of the discussion will apply to any vehicle with a drive system, collision avoidance, and navigation sensors, which is, of course, what makes a vehicle autonomous. And it is with these sensors and a drive system that the installer must become familiar in order to foresee potential trouble areas in the physical, technical, and human environment.
The strength of friendship ties in proximity sensor data.

PubMed

Sekara, Vedran; Lehmann, Sune

2014-01-01

Understanding how people interact and socialize is important in many contexts from disease control to urban planning. Datasets that capture this specific aspect of human life have increased in size and availability over the last few years. We have yet to understand, however, to what extent such electronic datasets may serve as a valid proxy for real life social interactions. For an observational dataset, gathered using mobile phones, we analyze the problem of identifying transient and non-important links, as well as how to highlight important social interactions. Applying the Bluetooth signal strength parameter to distinguish between observations, we demonstrate that weak links, compared to strong links, have a lower probability of being observed at later times, while such links-on average-also have lower link-weights and probability of sharing an online friendship. Further, the role of link-strength is investigated in relation to social network properties.
76 FR 18247 - Notice of Receipt of Complaint; Solicitation of Comments Relating to the Public Interest

Federal Register 2010, 2011, 2012, 2013, 2014

2011-04-01

... Certain Electronic Devices, Including Mobile Phones, Mobile Tablets, Portable Music Players, and Computers... importation of certain electronic devices, including mobile phones, mobile tablets, portable music players...
Survey on Different Samsung with Nokia Smart Mobile Phones in the Specific Absorption Rate Electrical Field of Head

PubMed Central

Fakhri, Yadolah; Alinejad, Azim; Keramati, Hassan; Bay, Abotaleb; Avazpour, Moayed; Zandsalimi, Yahya; Moradi, Bigard; Amirhajeloo, Leila Rasouli; Mirzaei, Maryam

2016-01-01

The use of smart phones is increasing in the world. This excessive use, especially in the last two decades, has created too much concern on the effects of emitted electromagnetic fields and specific absorption rate on human health. In this descriptive-analytical study of the electric field resulting from smart phones of Samsung and Nokia by portable measuring device, electromagnetic field, Model HI-3603-VDT/VLF, were measured. Then, head absorption rate was calculated in these two mobiles by ICNIRP equation. Finally, the comparison of specific absorption rate, especially between Samsung and Nokia smart phones, was conducted by T-Test statistics analysis. The mean of electric field for Samsung and Nokia smart mobile phones was obtained 1.8 ±0.19 v/m and 2.23±0.39 v/m, respectively, while the range of the electric field was obtained as 1.56-2.21 v/m and 1.69-2.89 v/m for them, respectively. The mean of specific absorption rate in Samsung and Nokia was obtained 0.002 ± 0.0005 W/Kg and 0.0041±0.0013 W/Kg at the frequency of 900 MHz and 0.004±0.001 W/Kg and 0.0062±0.0002 W/Kg at the frequency of 1800 MHz respectively. The ratio of mean electronic field to guidance in the Samsung mobile phone at the frequency of 900 MHz and 1800 MHz was 4.36% and 3.34%, while was 5.62% and 4.31% in the Nokia mobile phone, respectively. The ratio of mean head specific absorption rate in smart mobile phones of Samsung and Nokia in the guidance level at the frequency of 900 was 0.15% and 0.25%, respectively, while was 0.23% and 0.38% at the frequency of 1800 MHz, respectively. The rate of specific absorption of Nokia smart mobile phones at the frequencies of 900 and 1800 MHz was significantly higher than Samsung (p value <0.05). Hence, we can say that in a fixed period, health risks of Nokia smart phones is higher than Samsung smart mobile phone. PMID:27157169

Survey on Different Samsung with Nokia Smart Mobile Phones in the Specific Absorption Rate Electrical Field of Head.

PubMed

Fakhri, Yadolah; Alinejad, Azim; Keramati, Hassan; Bay, Abotaleb; Avazpour, Moayed; Zandsalimi, Yahya; Moradi, Bigard; Rasouli Amirhajeloo, Leila; Mirzaei, Maryam

2016-09-01

The use of smart phones is increasing in the world. This excessive use, especially in the last two decades, has created too much concern on the effects of emitted electromagnetic fields and specific absorption rate on human health. In this descriptive-analytical study of the electric field resulting from smart phones of Samsung and Nokia by portable measuring device, electromagnetic field, Model HI-3603-VDT/VLF, were measured. Then, head absorption rate was calculated in these two mobiles by ICNIRP equation. Finally, the comparison of specific absorption rate, especially between Samsung and Nokia smart phones, was conducted by T-Test statistics analysis. The mean of electric field for Samsung and Nokia smart mobile phones was obtained 1.8 ±0.19 v/m and 2.23±0.39 v/m , respectively, while the range of the electric field was obtained as 1.56-2.21 v/m and 1.69-2.89 v/m for them, respectively. The mean of specific absorption rate in Samsung and Nokia was obtained 0.002 ± 0.0005 W/Kg and 0.0041±0.0013 W/Kg at the frequency of 900 MHz and 0.004±0.001 W/Kg and 0.0062±0.0002 W/Kg at the frequency of 1800 MHz respectively. The ratio of mean electronic field to guidance in the Samsung mobile phone at the frequency of 900 MHz and 1800 MHz was 4.36% and 3.34%, while was 5.62% and 4.31% in the Nokia mobile phone, respectively. The ratio of mean head specific absorption rate in smart mobile phones of Samsung and Nokia in the guidance level at the frequency of 900 was 0.15% and 0.25%, respectively, while was 0.23 %and 0.38% at the frequency of 1800 MHz, respectively. The rate of specific absorption of Nokia smart mobile phones at the frequencies of 900 and 1800 MHz was significantly higher than Samsung (p value <0.05). Hence, we can say that in a fixed period, health risks of Nokia smart phones is higher than Samsung smart mobile phone.
Knowledge mobilization in bridging patient-practitioner-researcher boundaries: A systematic integrative review protocol.

PubMed

Cowdell, Fiona; Booth, Andrew; Appleby, Ben

2017-11-01

To review published literature to identify when and how patients and healthcare practitioners have been involved in knowledge mobilization activity and the impact this may have had on their care. Improving patient outcomes, satisfaction and quality of care is increasingly reliant on shared decision-making between health professionals and patients. Knowledge mobilization, at its simplest: "moving knowledge to where it can be most useful" is a growing field of academic study. To date, it appears that much effort has focused on moving knowledge from researchers to healthcare practitioners. Knowledge mobilization to patients is currently under-researched. Integrative review. Methods of integrative review will be used to address the review problem. PRISMA guidelines were used as a general framework to guide structuring and reporting the review. Elements of method-specific reporting guidelines for specific streams of evidence will be used as required. This review will aim to provide a broad and deep understanding of patient-practitioner-researcher engagement in knowledge mobilization activity. This synthesis of the extant literature should offer insights into the optimum characteristics of methods for bridging patient-practitioner-researcher boundaries in knowledge mobilization action. © 2017 John Wiley & Sons Ltd.
Modeling of anomalous electron mobility in Hall thrusters

DOE Office of Scientific and Technical Information (OSTI.GOV)

Koo, Justin W.; Boyd, Iain D.

Accurate modeling of the anomalous electron mobility is absolutely critical for successful simulation of Hall thrusters. In this work, existing computational models for the anomalous electron mobility are used to simulate the UM/AFRL P5 Hall thruster (a 5 kW laboratory model) in a two-dimensional axisymmetric hybrid particle-in-cell Monte Carlo collision code. Comparison to experimental results indicates that, while these computational models can be tuned to reproduce the correct thrust or discharge current, it is very difficult to match all integrated performance parameters (thrust, power, discharge current, etc.) simultaneously. Furthermore, multiple configurations of these computational models can produce reasonable integrated performancemore » parameters. A semiempirical electron mobility profile is constructed from a combination of internal experimental data and modeling assumptions. This semiempirical electron mobility profile is used in the code and results in more accurate simulation of both the integrated performance parameters and the mean potential profile of the thruster. Results indicate that the anomalous electron mobility, while absolutely necessary in the near-field region, provides a substantially smaller contribution to the total electron mobility in the high Hall current region near the thruster exit plane.« less
Object Transportation by Two Mobile Robots with Hand Carts

PubMed Central

Hara, Tatsunori

2014-01-01

This paper proposes a methodology by which two small mobile robots can grasp, lift, and transport large objects using hand carts. The specific problems involve generating robot actions and determining the hand cart positions to achieve the stable loading of objects onto the carts. These problems are solved using nonlinear optimization, and we propose an algorithm for generating robot actions. The proposed method was verified through simulations and experiments using actual devices in a real environment. The proposed method could reduce the number of robots required to transport large objects with 50–60%. In addition, we demonstrated the efficacy of this task in real environments where errors occur in robot sensing and movement. PMID:27433499
Object Transportation by Two Mobile Robots with Hand Carts.

PubMed

Sakuyama, Takuya; Figueroa Heredia, Jorge David; Ogata, Taiki; Hara, Tatsunori; Ota, Jun

2014-01-01

This paper proposes a methodology by which two small mobile robots can grasp, lift, and transport large objects using hand carts. The specific problems involve generating robot actions and determining the hand cart positions to achieve the stable loading of objects onto the carts. These problems are solved using nonlinear optimization, and we propose an algorithm for generating robot actions. The proposed method was verified through simulations and experiments using actual devices in a real environment. The proposed method could reduce the number of robots required to transport large objects with 50-60%. In addition, we demonstrated the efficacy of this task in real environments where errors occur in robot sensing and movement.
Energy optimization in mobile sensor networks

NASA Astrophysics Data System (ADS)

Yu, Shengwei

Mobile sensor networks are considered to consist of a network of mobile robots, each of which has computation, communication and sensing capabilities. Energy efficiency is a critical issue in mobile sensor networks, especially when mobility (i.e., locomotion control), routing (i.e., communications) and sensing are unique characteristics of mobile robots for energy optimization. This thesis focuses on the problem of energy optimization of mobile robotic sensor networks, and the research results can be extended to energy optimization of a network of mobile robots that monitors the environment, or a team of mobile robots that transports materials from stations to stations in a manufacturing environment. On the energy optimization of mobile robotic sensor networks, our research focuses on the investigation and development of distributed optimization algorithms to exploit the mobility of robotic sensor nodes for network lifetime maximization. In particular, the thesis studies these five problems: 1. Network-lifetime maximization by controlling positions of networked mobile sensor robots based on local information with distributed optimization algorithms; 2. Lifetime maximization of mobile sensor networks with energy harvesting modules; 3. Lifetime maximization using joint design of mobility and routing; 4. Optimal control for network energy minimization; 5. Network lifetime maximization in mobile visual sensor networks. In addressing the first problem, we consider only the mobility strategies of the robotic relay nodes in a mobile sensor network in order to maximize its network lifetime. By using variable substitutions, the original problem is converted into a convex problem, and a variant of the sub-gradient method for saddle-point computation is developed for solving this problem. An optimal solution is obtained by the method. Computer simulations show that mobility of robotic sensors can significantly prolong the lifetime of the whole robotic sensor network while consuming negligible amount of energy for mobility cost. For the second problem, the problem is extended to accommodate mobile robotic nodes with energy harvesting capability, which makes it a non-convex optimization problem. The non-convexity issue is tackled by using the existing sequential convex approximation method, based on which we propose a novel procedure of modified sequential convex approximation that has fast convergence speed. For the third problem, the proposed procedure is used to solve another challenging non-convex problem, which results in utilizing mobility and routing simultaneously in mobile robotic sensor networks to prolong the network lifetime. The results indicate that joint design of mobility and routing has an edge over other methods in prolonging network lifetime, which is also the justification for the use of mobility in mobile sensor networks for energy efficiency purpose. For the fourth problem, we include the dynamics of the robotic nodes in the problem by modeling the networked robotic system using hybrid systems theory. A novel distributed method for the networked hybrid system is used to solve the optimal moving trajectories for robotic nodes and optimal network links, which are not answered by previous approaches. Finally, the fact that mobility is more effective in prolonging network lifetime for a data-intensive network leads us to apply our methods to study mobile visual sensor networks, which are useful in many applications. We investigate the joint design of mobility, data routing, and encoding power to help improving the video quality while maximizing the network lifetime. This study leads to a better understanding of the role mobility can play in data-intensive surveillance sensor networks.
Magnetic correlations in La(2-x)Sr(x)CuO4 from NQR relaxation and specific heat

NASA Technical Reports Server (NTRS)

Borsa, F.; Rigamonti, A.

1990-01-01

La-139 and Cu-63 Nuclear Quadrupole Resonance (NQR) relaxation measurements in La(2-x)Sr(x)CuO4 for O = to or less than 0.3 and in the temperature range 1.6 + 450 K are analyzed in terms of Cu(++) magnetic correlations and dynamics. It is described how the magnetic correlations that would result from Cu-Cu exchange are reduced by mobile charge defects related to x-doping. A comprehensive picture is given which explains satisfactorily the x and T dependence of the correlation time, of the correlation length and of the Neel temperature T(sub n)(x) as well as being consistent with known electrical resistivity and magnetic susceptibility measurements. It is discussed how, in the superconducting samples, the mobile defects also cause the decrease, for T yields T(sub c)(+) of the hyperfine Cu electron-nucleus effective interaction, leading to the coexistence of quasi-localized, reduced magnetic moments from 3d Cu electrons and mobile oxygen p-hole carriers. The temperature dependence of the effective hyperfine field around the superconducting transition yields an activation energy which could be related to the pairing energy. New specific heat measurements are also presented and discussed in terms of the above picture.
78 FR 34132 - Certain Portable Electronic Communications Devices, Including Mobile Phones and Components...

Federal Register 2010, 2011, 2012, 2013, 2014

2013-06-06

... INTERNATIONAL TRADE COMMISSION [Docket No 2958] Certain Portable Electronic Communications Devices, Including Mobile Phones and Components Thereof; Correction to Notice of Receipt of Complaint; Solicitation... of complaint entitled Certain Portable Electronic Communications Devices, Including Mobile Phones and...
77 FR 15390 - Certain Mobile Electronic Devices Incorporating Haptics; Receipt of Amended Complaint...

Federal Register 2010, 2011, 2012, 2013, 2014

2012-03-15

... INTERNATIONAL TRADE COMMISSION [DN 2875] Certain Mobile Electronic Devices Incorporating Haptics.... International Trade Commission. ACTION: Notice. SUMMARY: Notice is hereby given that the U.S. International Trade Commission has received an amended complaint entitled Certain Mobile Electronic Devices...
Planar Ohmic Contacts to Al 0.45 Ga 0.55 N/Al 0.3 Ga 0.7 N High Electron Mobility Transistors

DOE PAGES

Klein, Brianna A.; Baca, Albert G.; Armstrong, Andrew M.; ...

2017-09-23

Here, we present a low resistance, straightforward planar ohmic contact for Al 0.45Ga 0.55N/Al 0.3Ga 0.7N high electron mobility transistors. Five metal stacks (a/Al/b/Au; a = Ti, Zr, V, Nb/Ti; b = Ni, Mo, V) were evaluated at three individual annealing temperatures (850, 900, and 950°C). The Ti/Al/Ni/Au achieved the lowest specific contact resistance at a 900°C anneal temperature. Transmission electron microscopy analysis revealed a metal-semiconductor interface of Ti-Al-Au for an ohmic (900°C anneal) and a Schottky (850°C anneal) Ti/Al/Ni/Au stack. HEMTs were fabricated using the optimized recipe with resulting contacts that had room-temperature specific contact resistances of ρ c = 2.5 × 10 -5 Ω cm², sheet resistances of R SH = 3.9 kΩ/more » $$\\blacksquare$$, and maximum current densities of 75 mA/mm (at VGATE of 2 V). Electrical measurements from -50 to 200°C had decreasing specific contact resistance and increasing sheet resistance, with increasing temperature. These contacts enabled state-of-the-art performance of Al 0.45Ga 0.55N/Al 0.3Ga 0.7N HEMTs.« less
Planar Ohmic Contacts to Al 0.45 Ga 0.55 N/Al 0.3 Ga 0.7 N High Electron Mobility Transistors

DOE Office of Scientific and Technical Information (OSTI.GOV)

Klein, Brianna A.; Baca, Albert G.; Armstrong, Andrew M.

Here, we present a low resistance, straightforward planar ohmic contact for Al 0.45Ga 0.55N/Al 0.3Ga 0.7N high electron mobility transistors. Five metal stacks (a/Al/b/Au; a = Ti, Zr, V, Nb/Ti; b = Ni, Mo, V) were evaluated at three individual annealing temperatures (850, 900, and 950°C). The Ti/Al/Ni/Au achieved the lowest specific contact resistance at a 900°C anneal temperature. Transmission electron microscopy analysis revealed a metal-semiconductor interface of Ti-Al-Au for an ohmic (900°C anneal) and a Schottky (850°C anneal) Ti/Al/Ni/Au stack. HEMTs were fabricated using the optimized recipe with resulting contacts that had room-temperature specific contact resistances of ρ c = 2.5 × 10 -5 Ω cm², sheet resistances of R SH = 3.9 kΩ/more » $$\\blacksquare$$, and maximum current densities of 75 mA/mm (at VGATE of 2 V). Electrical measurements from -50 to 200°C had decreasing specific contact resistance and increasing sheet resistance, with increasing temperature. These contacts enabled state-of-the-art performance of Al 0.45Ga 0.55N/Al 0.3Ga 0.7N HEMTs.« less
Electronic Portfolios.

ERIC Educational Resources Information Center

Purves, Alan C.

1996-01-01

Outlines three forms of electronic portfolio based on a student's work, a class project about a specific topic, and a class seminar on a broad topic. Discusses logistical problems of management, access, and cross-referencing; technical problems of input, access, and copying; and theoretical issues of the lack of realia, of ownership and copyright,…
Electron mobility on the surface of liquid Helium: influence of surface level atoms and depopulation of lowest subbands

DOE Office of Scientific and Technical Information (OSTI.GOV)

Grigoriev, P. D., E-mail: grigorev@itp.ac.ru; Dyugaev, A. M.; Lebedeva, E. V.

2008-02-15

The temperature dependence of electron mobility is examined. We calculate the contribution to the electron scattering rate from the surface level atoms (SLAs), proposed in [10]. This contribution is substantial at low temperatures T < 0.5, when the He vapor concentration is exponentially small. We also study the effect of depopulation of the lowest energy subband, which leads to an increase in the electron mobility at high temperature. The results explain certain long-standing discrepancies between the existing theory and experiment on electron mobility on the surface of liquid helium.
A III-V nanowire channel on silicon for high-performance vertical transistors.

PubMed

Tomioka, Katsuhiro; Yoshimura, Masatoshi; Fukui, Takashi

2012-08-09

Silicon transistors are expected to have new gate architectures, channel materials and switching mechanisms in ten years' time. The trend in transistor scaling has already led to a change in gate structure from two dimensions to three, used in fin field-effect transistors, to avoid problems inherent in miniaturization such as high off-state leakage current and the short-channel effect. At present, planar and fin architectures using III-V materials, specifically InGaAs, are being explored as alternative fast channels on silicon because of their high electron mobility and high-quality interface with gate dielectrics. The idea of surrounding-gate transistors, in which the gate is wrapped around a nanowire channel to provide the best possible electrostatic gate control, using InGaAs channels on silicon, however, has been less well investigated because of difficulties in integrating free-standing InGaAs nanostructures on silicon. Here we report the position-controlled growth of vertical InGaAs nanowires on silicon without any buffering technique and demonstrate surrounding-gate transistors using InGaAs nanowires and InGaAs/InP/InAlAs/InGaAs core-multishell nanowires as channels. Surrounding-gate transistors using core-multishell nanowire channels with a six-sided, high-electron-mobility transistor structure greatly enhance the on-state current and transconductance while keeping good gate controllability. These devices provide a route to making vertically oriented transistors for the next generation of field-effect transistors and may be useful as building blocks for wireless networks on silicon platforms.
Understanding the psychology of mobile gambling: A behavioural synthesis.

PubMed

James, Richard J E; O'Malley, Claire; Tunney, Richard J

2017-08-01

This manuscript reviews the extant literature on key issues related to mobile gambling and considers whether the potential risks of harm emerging from this platform are driven by pre-existing comorbidities or by psychological processes unique to mobile gambling. We propose an account based on associative learning that suggests this form of gambling is likely to show distinctive features compared with other gambling technologies. Smartphones are a rapidly growing platform on which individuals can gamble using specifically designed applications, adapted websites or text messaging. This review considers how mobile phone use interacts with psychological processes relevant to gambling, the games users are likely to play on smartphones, and the interactions afforded by smartphones. Our interpretation of the evidence is that the schedules of reinforcement found in gambling interact with the ways in which people tend to use smartphones that may expedite the acquisition of maladaptive learned behaviours such as problem gambling. This account is consistent with existing theories and frameworks of problem gambling and has relevance to other forms of mobile phone use. © 2016 The Authors. British Journal of Psychology published by John Wiley & Sons Ltd on behalf of the British Psychological Society.
A thermodynamic model to predict electron mobility in superfluid helium.

PubMed

Aitken, Frédéric; Volino, Ferdinand; Mendoza-Luna, Luis Guillermo; Haeften, Klaus von; Eloranta, Jussi

2017-06-21

Electron mobility in superfluid helium is modeled between 0.1 and 2.2 K by a van der Waals-type thermodynamic equation of state, which relates the free volume of solvated electrons to temperature, density, and phase dependent internal pressure. The model is first calibrated against known electron mobility reference data along the saturated vapor pressure line and then validated to reproduce the existing mobility literature values as a function of pressure and temperature with at least 10% accuracy. Four different electron mobility regimes are identified: (1) Landau critical velocity limit (T ≈ 0), (2) mobility limited by thermal phonons (T < 0.6 K), (3) thermal phonon and discrete roton scattering ("roton gas") limited mobility (0.6 K < T < 1.2 K), and (4) the viscous liquid ("roton continuum") limit (T > 1.2 K) where the ion solvation structure directly determines the mobility. In the latter regime, the Stokes equation can be used to estimate the hydrodynamic radius of the solvated electron based on its mobility and fluid viscosity. To account for the non-continuum behavior appearing below 1.2 K, the temperature and density dependent Millikan-Cunningham factor is introduced. The hydrodynamic electron bubble radii predicted by the present model appear generally larger than the solvation cavity interface barycenter values obtained from density functional theory (DFT) calculations. Based on the classical Stokes law, this difference can arise from the variation of viscosity and flow characteristics around the electron. The calculated DFT liquid density profiles show distinct oscillations at the vacuum/liquid interface, which increase the interface rigidity.
Multi-Objective Constraint Satisfaction for Mobile Robot Area Defense

DTIC Science & Technology

2010-03-01

17 NSGA-II non-dominated sorting genetic algorithm II . . . . . . . . . . . . . . . . . . . 17 jMetal Metaheuristic Algorithms in...to alert the other agents and ensure trust in the system. This research presents an algorithm that tasks robots to meet the two specific goals of...problem is defined as a constraint satisfaction problem solved using the Non-dominated Sorting Genetic Algorithm II (NSGA-II). Both goals of
Robot path planning algorithm based on symbolic tags in dynamic environment

NASA Astrophysics Data System (ADS)

Vokhmintsev, A.; Timchenko, M.; Melnikov, A.; Kozko, A.; Makovetskii, A.

2017-09-01

The present work will propose a new heuristic algorithms for path planning of a mobile robot in an unknown dynamic space that have theoretically approved estimates of computational complexity and are approbated for solving specific applied problems.
The Role of Exo-(1→4)-β-galactanase in the Mobilization of Polysaccharides from the Cotyledon Cell Walls of Lupinus angustifolius Following Germination

PubMed Central

BUCKERIDGE, MARCOS S.; HUTCHEON, IAN S.; REID, J. S. GRANT

2005-01-01

• Background and Aims The cotyledons of Lupinus angustifolius contain large amounts of cell wall storage polysaccharide (CWSP) composed mainly of (1→4)-β-linked d-galactose residues in the form of branches attached to a rhamnogalacturonan core molecule. An exo-(1→4)-β-galactanase with a very high specificity towards (1→4)-β-linked d-galactan has been isolated from L. angustifolius cotyledons, and shown to vary (activity and specific protein) in step with CWSP mobilization. This work aimed to confirm the hypothesis that galactan is the main polymer retrieved from the wall during mobilization at the ultrastructural level, using the purified exo-galactanase as a probe. • Methods Storage mesophyll cell walls (‘ghosts’) were isolated from the cotyledons of imbibed but ungerminated lupin seeds, and also from cotyledons of seedlings after the mobilization of the CWSP. The pure exo-(1→4)-β-galactanase was coupled to colloidal gold particles and shown to be a specific probe for (1→4)-β-d-galactan. They were used to localize galactan in ultrathin sections of L. angustifolius cotyledonary mesophyll tissue during CWSP mobilization. • Key Results On comparing the morphologies of isolated cell walls, the post-mobilization ‘ghosts’ did not have the massive wall-thickenings of pre-mobilization walls. Compositional analysis showed that the post-mobilization walls were depleted in galactose and, to a lesser extent, in arabinose. When pre-mobilization ghosts were treated with the pure exo-galactanase, they became morphologically similar to the post-mobilization ghosts. They were depleted of approximately 70% of the galactose residues that would have been mobilized in vivo, and retained all the other sugar residues originally present. Sharply defined electron-transparent wall zones or pockets are associated with CWSP mobilization, being totally free of galactan, whereas wall areas immediately adjacent to them were apparently undepleted. • Conclusions The exo-(1→4)-β-galactanase is the principal enzyme involved in CWSP mobilization in lupin cotyledons in vivo. The storage walls dramatically change their texture during mobilization as most of the galactan is hydrolysed during seedling development. PMID:15994843
The role of exo-(1-->4)-beta-galactanase in the mobilization of polysaccharides from the cotyledon cell walls of Lupinus angustifolius following germination.

PubMed

Buckeridge, Marcos S; Hutcheon, Ian S; Reid, J S Grant

2005-09-01

The cotyledons of Lupinus angustifolius contain large amounts of cell wall storage polysaccharide (CWSP) composed mainly of (1-->4)-beta-linked D-galactose residues in the form of branches attached to a rhamnogalacturonan core molecule. An exo-(1-->4)-beta-galactanase with a very high specificity towards (1-->4)-beta-linked D-galactan has been isolated from L. angustifolius cotyledons, and shown to vary (activity and specific protein) in step with CWSP mobilization. This work aimed to confirm the hypothesis that galactan is the main polymer retrieved from the wall during mobilization at the ultrastructural level, using the purified exo-galactanase as a probe. Storage mesophyll cell walls ('ghosts') were isolated from the cotyledons of imbibed but ungerminated lupin seeds, and also from cotyledons of seedlings after the mobilization of the CWSP. The pure exo-(1-->4)-beta-galactanase was coupled to colloidal gold particles and shown to be a specific probe for (1-->4)-beta-D-galactan. They were used to localize galactan in ultrathin sections of L. angustifolius cotyledonary mesophyll tissue during CWSP mobilization. On comparing the morphologies of isolated cell walls, the post-mobilization 'ghosts' did not have the massive wall-thickenings of pre-mobilization walls. Compositional analysis showed that the post-mobilization walls were depleted in galactose and, to a lesser extent, in arabinose. When pre-mobilization ghosts were treated with the pure exo-galactanase, they became morphologically similar to the post-mobilization ghosts. They were depleted of approximately 70% of the galactose residues that would have been mobilized in vivo, and retained all the other sugar residues originally present. Sharply defined electron-transparent wall zones or pockets are associated with CWSP mobilization, being totally free of galactan, whereas wall areas immediately adjacent to them were apparently undepleted. The exo-(1-->4)-beta-galactanase is the principal enzyme involved in CWSP mobilization in lupin cotyledons in vivo. The storage walls dramatically change their texture during mobilization as most of the galactan is hydrolysed during seedling development.

Augmented paper maps: Exploring the design space of a mixed reality system

NASA Astrophysics Data System (ADS)

Paelke, Volker; Sester, Monika

Paper maps and mobile electronic devices have complementary strengths and shortcomings in outdoor use. In many scenarios, like small craft sailing or cross-country trekking, a complete replacement of maps is neither useful nor desirable. Paper maps are fail-safe, relatively cheap, offer superior resolution and provide large scale overview. In uses like open-water sailing it is therefore mandatory to carry adequate maps/charts. GPS based mobile devices, on the other hand, offer useful features like automatic positioning and plotting, real-time information update and dynamic adaptation to user requirements. While paper maps are now commonly used in combination with mobile GPS devices, there is no meaningful integration between the two, and the combined use leads to a number of interaction problems and potential safety issues. In this paper we explore the design space of augmented paper maps in which maps are augmented with additional functionality through a mobile device to achieve a meaningful integration between device and map that combines their respective strengths.
A security scheme of SMS system

NASA Astrophysics Data System (ADS)

Zhang, Fangzhou; Yang, Hong-Wei; Song, Chuck

2005-02-01

With the prosperous development and the use of SMS, more and more important information need to be transferred through the wireless and mobile networks by the users. But in the GSM/GPRS network, the SMS messages are transferred in text mode through the signaling channel and there is no integrality for SMS messages. Because of the speciality of the mobile communications, the security of signaling channel is very weak. So we need to improve and enhance the security and integrality of SMS. At present, developed investigation based on SMS security is still incomplete. The key distribution and management is not perfect to meet the usability in a wide area. This paper introduces a high-level security method to solve this problem. We design the Secure SMS of GSM/GPRS in order to improve the security of the important information that need to be transferred by the mobile networks. Using this method, we can improve the usability of E-payment and other mobile electronic commerce.
Mobile technology supporting trainee doctors’ workplace learning and patient care: an evaluation

PubMed Central

2013-01-01

Background The amount of information needed by doctors has exploded. The nature of knowledge (explicit and tacit) and processes of knowledge acquisition and participation are complex. Aiming to assist workplace learning, Wales Deanery funded “iDoc”, a project offering trainee doctors a Smartphone library of medical textbooks. Methods Data on trainee doctors’ (Foundation Year 2) workplace information seeking practice was collected by questionnaire in 2011 (n = 260). iDoc baseline questionnaires (n = 193) collected data on Smartphone usage alongside other workplace information sources. Case reports (n = 117) detail specific instances of Smartphone use. Results Most frequently (daily) used information sources in the workplace: senior medical staff (80% F2 survey; 79% iDoc baseline); peers (70%; 58%); and other medical/nursing team staff (53% both datasets). Smartphones were used more frequently by males (p < 0.01). Foundation Year 1 (newly qualified) was judged the most useful time to have a Smartphone library because of increased responsibility and lack of knowledge/experience. Preferred information source varied by question type: hard copy texts for information-based questions; varied resources for skills queries; and seniors for more complex problems. Case reports showed mobile technology used for simple (information-based), complex (problem-based) clinical questions and clinical procedures (skills-based scenarios). From thematic analysis, the Smartphone library assisted: teaching and learning from observation; transition from medical student to new doctor; trainee doctors’ discussions with seniors; independent practice; patient care; and this ‘just-in-time’ access to reliable information supported confident and efficient decision-making. Conclusion A variety of information sources are used regularly in the workplace. Colleagues are used daily but seniors are not always available. During transitions, constant access to the electronic library was valued. It helped prepare trainee doctors for discussions with their seniors, assisting the interchange between explicit and tacit knowledge. By supporting accurate prescribing and treatment planning, the electronic library contributed to enhanced patient care. Trainees were more rapidly able to medicate patients to reduce pain and more quickly call for specific assessments. However, clinical decision-making often requires dialogue: what Smartphone technology can do is augment, not replace, discussion with their colleagues in the community of practice. PMID:23336964
Lead Halide Perovskites as Charge Generation Layers for Electron Mobility Measurement in Organic Semiconductors.

PubMed

Love, John A; Feuerstein, Markus; Wolff, Christian M; Facchetti, Antonio; Neher, Dieter

2017-12-06

Hybrid lead halide perovskites are introduced as charge generation layers (CGLs) for the accurate determination of electron mobilities in thin organic semiconductors. Such hybrid perovskites have become a widely studied photovoltaic material in their own right, for their high efficiencies, ease of processing from solution, strong absorption, and efficient photogeneration of charge. Time-of-flight (ToF) measurements on bilayer samples consisting of the perovskite CGL and an organic semiconductor layer of different thickness are shown to be determined by the carrier motion through the organic material, consistent with the much higher charge carrier mobility in the perovskite. Together with the efficient photon-to-electron conversion in the perovskite, this high mobility imbalance enables electron-only mobility measurement on relatively thin application-relevant organic films, which would not be possible with traditional ToF measurements. This architecture enables electron-selective mobility measurements in single components as well as bulk-heterojunction films as demonstrated in the prototypical polymer/fullerene blends. To further demonstrate the potential of this approach, electron mobilities were measured as a function of electric field and temperature in an only 127 nm thick layer of a prototypical electron-transporting perylene diimide-based polymer, and found to be consistent with an exponential trap distribution of ca. 60 meV. Our study furthermore highlights the importance of high mobility charge transporting layers when designing perovskite solar cells.
Towards Real Information on Demand.

ERIC Educational Resources Information Center

Barker, Philip

The phrase "information on demand" is often used to describe situations in which digital electronic information can be delivered to particular points of need at times and in ways that are determined by the specific requirements of individual consumers or client groups. The advent of "mobile" computing equipment now makes the…
Breaking Out of the Lab: Measuring Real-Time Responses to Televised Political Content in Real-World Settings.

PubMed

Maier, Jürgen; Hampe, J Felix; Jahn, Nico

2016-01-01

Real-time response (RTR) measurement is an important technique for analyzing human processing of electronic media stimuli. Although it has been demonstrated that RTR data are reliable and internally valid, some argue that they lack external validity. The reason for this is that RTR measurement is restricted to a laboratory environment due to its technical requirements. This paper introduces a smartphone app that 1) captures real-time responses using the dial technique and 2) provides a solution for one of the most important problems in RTR measurement, the (automatic) synchronization of RTR data. In addition, it explores the reliability and validity of mobile RTR measurement by comparing the real-time reactions of two samples of young and well-educated voters to the 2013 German televised debate. Whereas the first sample participated in a classical laboratory study, the second sample was equipped with our mobile RTR system and watched the debate at home. Results indicate that the mobile RTR system yields similar results to the lab-based RTR measurement, providing evidence that laboratory studies using RTR are externally valid. In particular, the argument that the artificial reception situation creates artificial results has to be questioned. In addition, we conclude that RTR measurement outside the lab is possible. Hence, mobile RTR opens the door for large-scale studies to better understand the processing and impact of electronic media content.
Breaking Out of the Lab

PubMed Central

Maier, Jürgen; Hampe, J. Felix; Jahn, Nico

2016-01-01

Real-time response (RTR) measurement is an important technique for analyzing human processing of electronic media stimuli. Although it has been demonstrated that RTR data are reliable and internally valid, some argue that they lack external validity. The reason for this is that RTR measurement is restricted to a laboratory environment due to its technical requirements. This paper introduces a smartphone app that 1) captures real-time responses using the dial technique and 2) provides a solution for one of the most important problems in RTR measurement, the (automatic) synchronization of RTR data. In addition, it explores the reliability and validity of mobile RTR measurement by comparing the real-time reactions of two samples of young and well-educated voters to the 2013 German televised debate. Whereas the first sample participated in a classical laboratory study, the second sample was equipped with our mobile RTR system and watched the debate at home. Results indicate that the mobile RTR system yields similar results to the lab-based RTR measurement, providing evidence that laboratory studies using RTR are externally valid. In particular, the argument that the artificial reception situation creates artificial results has to be questioned. In addition, we conclude that RTR measurement outside the lab is possible. Hence, mobile RTR opens the door for large-scale studies to better understand the processing and impact of electronic media content. PMID:27274577
High Electron Mobility Transistor Structures on Sapphire Substrates Using CMOS Compatible Processing Techniques

NASA Technical Reports Server (NTRS)

Mueller, Carl; Alterovitz, Samuel; Croke, Edward; Ponchak, George

2004-01-01

System-on-a-chip (SOC) processes are under intense development for high-speed, high frequency transceiver circuitry. As frequencies, data rates, and circuit complexity increases, the need for substrates that enable high-speed analog operation, low-power digital circuitry, and excellent isolation between devices becomes increasingly critical. SiGe/Si modulation doped field effect transistors (MODFETs) with high carrier mobilities are currently under development to meet the active RF device needs. However, as the substrate normally used is Si, the low-to-modest substrate resistivity causes large losses in the passive elements required for a complete high frequency circuit. These losses are projected to become increasingly troublesome as device frequencies progress to the Ku-band (12 - 18 GHz) and beyond. Sapphire is an excellent substrate for high frequency SOC designs because it supports excellent both active and passive RF device performance, as well as low-power digital operations. We are developing high electron mobility SiGe/Si transistor structures on r-plane sapphire, using either in-situ grown n-MODFET structures or ion-implanted high electron mobility transistor (HEMT) structures. Advantages of the MODFET structures include high electron mobilities at all temperatures (relative to ion-implanted HEMT structures), with mobility continuously improving to cryogenic temperatures. We have measured electron mobilities over 1,200 and 13,000 sq cm/V-sec at room temperature and 0.25 K, respectively in MODFET structures. The electron carrier densities were 1.6 and 1.33 x 10(exp 12)/sq cm at room and liquid helium temperature, respectively, denoting excellent carrier confinement. Using this technique, we have observed electron mobilities as high as 900 sq cm/V-sec at room temperature at a carrier density of 1.3 x 10(exp 12)/sq cm. The temperature dependence of mobility for both the MODFET and HEMT structures provides insights into the mechanisms that allow for enhanced electron mobility as well as the processes that limit mobility, and will be presented.
Positron studies of defected metals, metallic surfaces

NASA Astrophysics Data System (ADS)

Bansil, A.

Specific problems proposed under this project included the treatment of electronic structure and momentum density in various disordered and defected systems. Since 1987, when the new high-temperature superconductors were discovered, the project focused extensively on questions concerning the electronic structure and Fermiology of high-(Tc) superconductors, in particular, (1) momentum density and positron experiments, (2) angle-resolved photoemission intensities, and (3) effects of disorder and substitutions in the high-(Tc)'s. The specific progress made in each of these problems is summarized.
Organic Ferroelectric-Based 1T1T Random Access Memory Cell Employing a Common Dielectric Layer Overcoming the Half-Selection Problem.

PubMed

Zhao, Qiang; Wang, Hanlin; Ni, Zhenjie; Liu, Jie; Zhen, Yonggang; Zhang, Xiaotao; Jiang, Lang; Li, Rongjin; Dong, Huanli; Hu, Wenping

2017-09-01

Organic electronics based on poly(vinylidenefluoride/trifluoroethylene) (P(VDF-TrFE)) dielectric is facing great challenges in flexible circuits. As one indispensable part of integrated circuits, there is an urgent demand for low-cost and easy-fabrication nonvolatile memory devices. A breakthrough is made on a novel ferroelectric random access memory cell (1T1T FeRAM cell) consisting of one selection transistor and one ferroelectric memory transistor in order to overcome the half-selection problem. Unlike complicated manufacturing using multiple dielectrics, this system simplifies 1T1T FeRAM cell fabrication using one common dielectric. To achieve this goal, a strategy for semiconductor/insulator (S/I) interface modulation is put forward and applied to nonhysteretic selection transistors with high performances for driving or addressing purposes. As a result, high hole mobility of 3.81 cm 2 V -1 s -1 (average) for 2,6-diphenylanthracene (DPA) and electron mobility of 0.124 cm 2 V -1 s -1 (average) for N,N'-1H,1H-perfluorobutyl dicyanoperylenecarboxydiimide (PDI-FCN 2 ) are obtained in selection transistors. In this work, we demonstrate this technology's potential for organic ferroelectric-based pixelated memory module fabrication. © 2017 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.
Electron mobility limited by optical phonons in wurtzite InGaN/GaN core-shell nanowires

NASA Astrophysics Data System (ADS)

Liu, W. H.; Qu, Y.; Ban, S. L.

2017-09-01

Based on the force-balance and energy-balance equations, the optical phonon-limited electron mobility in InxGa1-xN/GaN core-shell nanowires (CSNWs) is discussed. It is found that the electrons tend to distribute in the core of the CSNWs due to the strong quantum confinement. Thus, the scattering from first kind of the quasi-confined optical (CO) phonons is more important than that from the interface (IF) and propagating (PR) optical phonons. Ternary mixed crystal and size effects on the electron mobility are also investigated. The results show that the PR phonons exist while the IF phonons disappear when the indium composition x < 0.047, and vice versa. Accordingly, the total electron mobility μ first increases and then decreases with indium composition x, and reaches a peak value of approximately 3700 cm2/(V.s) when x = 0.047. The results also show that the mobility μ increases as increasing the core radius of CSNWs due to the weakened interaction between the electrons and CO phonons. The total electron mobility limited by the optical phonons exhibits an obvious enhancement as decreasing temperature or increasing line electron density. Our theoretical results are expected to be helpful to develop electronic devices based on CSNWs.
Link technologies and BlackBerry mobile health (mHealth) solutions: a review.

PubMed

Adibi, Sasan

2012-07-01

The number of wearable wireless sensors is expected to grow to 400 million by the year 2014, while the number of operational mobile subscribers has already passed the 5.2 billion mark in 2011. This growth results in an increasing number of mobile applications including: Machine-to-Machine (M2M) communications, Electronic-Health (eHealth), and Mobile-Health (mHealth). A number of emerging mobile applications that require 3G and 4G mobile networks for data transport relate to telemedicine, including establishing, maintaining, and transmitting health-related information, research, education, and training. This review paper takes a closer look at these applications, specifically with regard to the healthcare industry and their underlying link technologies. The authors believe that the BlackBerry platform and the associated infrastructure (i.e., BlackBerry Enterprise Server) is a logical and practical solution for eHealth, mHealth, sensor and M2M deployments, which are considered in this paper.
77 FR 49458 - Certain Mobile Electronic Devices Incorporating Haptics; Amendment of the Complaint and Notice of...

Federal Register 2010, 2011, 2012, 2013, 2014

2012-08-16

... INTERNATIONAL TRADE COMMISSION [Investigation No. 337-TA-834] Certain Mobile Electronic Devices.... 1337 in the importation, sale for importation, and sale within the United States after importation of certain mobile electronic devices incorporating haptics, by reason of the infringement of claims of six...
77 FR 27078 - Certain Electronic Devices, Including Mobile Phones and Tablet Computers, and Components Thereof...

Federal Register 2010, 2011, 2012, 2013, 2014

2012-05-08

... Phones and Tablet Computers, and Components Thereof; Notice of Receipt of Complaint; Solicitation of... entitled Certain Electronic Devices, Including Mobile Phones and Tablet Computers, and Components Thereof... the United States after importation of certain electronic devices, including mobile phones and tablet...
76 FR 31983 - In the Matter of Certain Electronic Devices, Including Mobile Phones, Portable Music Players, and...

Federal Register 2010, 2011, 2012, 2013, 2014

2011-06-02

... INTERNATIONAL TRADE COMMISSION [Investigation No. 337-TA-701] In the Matter of Certain Electronic Devices, Including Mobile Phones, Portable Music Players, and Computers; Notice of Commission... States after importation of certain electronic devices, including mobile phones, portable music players...
Origin of the different transport properties of electron and hole polarons in an ambipolar polyselenophene-based conjugated polymer

NASA Astrophysics Data System (ADS)

Chen, Zhuoying; Bird, Matthew; Lemaur, Vincent; Radtke, Guillaume; Cornil, Jérôme; Heeney, Martin; McCulloch, Iain; Sirringhaus, Henning

2011-09-01

Understanding the mechanisms limiting ambipolar transport in conjugated polymer field-effect transistors (FETs) is of both fundamental and practical interest. Here, we present a systematic study comparing hole and electron charge transport in an ambipolar conjugated polymer, semicrystalline poly(3,3''-di-n-decylterselenophene) (PSSS). Starting from a detailed analysis of the device characteristics and temperature/charge-density dependence of the mobility, we interpret the difference between hole and electron transport through both the Vissenberg-Matters and the mobility-edge model. To obtain microscopic insight into the quantum mechanical wave function of the charges at a molecular level, we combine charge modulation spectroscopy (CMS) measuring the charge-induced absorption signatures from positive and negative polarons in these ambipolar FETs with corresponding density functional theory (DFT) calculations. We observe a significantly higher switch-on voltage for electrons than for holes due to deep electron trap states, but also a higher activation energy of the mobility for mobile electrons. The CMS spectra reveal that the electrons that remain mobile and contribute to the FET current have a wave function that is more localized onto a single polymer chain than that of holes, which is extended over several polymer chains. We interpret this as evidence that the transport properties of the mobile electrons in PSSS are still affected by the presence of deep electron traps. The more localized electron state could be due to the mobile electrons interacting with shallow trap states in the vicinity of a chemical, potentially water-related, impurity that might precede the capture of the electron into a deeply trapped state.
Correlates of mobile screen media use among children aged 0–8: a systematic review

PubMed Central

Jancey, Jonine; Subedi, Narayan; Leavy, Justine

2017-01-01

Objective This study is a systematic review of the peer-reviewed literature to identify the correlates of mobile screen media use among children aged 8 years and less. Setting Home or community-based studies were included in this review while child care or school-based studies were excluded. Participants Children aged 8 years or less were the study population. Studies that included larger age groups without subgroup analysis specific to the 0–8 years category were excluded. Eight electronic databases were searched for peer-reviewed English language primary research articles published or in press between January 2009 and March 2017 that have studied correlates of mobile screen media use in this age group. Outcome measure Mobile screen media use was the primary outcome measure. Mobile screen media use refers to children’s use of mobile screens, such as mobile phones, electronic tablets, handheld computers or personal digital assistants. Results Thirteen studies meeting the inclusion criteria were identified of which a total of 36 correlates were examined. Older children, children better skilled in using mobile screen media devices, those having greater access to such devices at home and whose parents had high mobile screen media use were more likely to have higher use of mobile screen media devices. No association existed with parent’s age, sex and education. Conclusion Limited research has been undertaken into young children’s mobile screen media use and most of the variables have been studied too infrequently for robust conclusions to be reached. Future studies with objective assessment of mobile screen media use and frequent examination of the potential correlates across multiple studies and settings are recommended. Trial registration number This review is registered with PROSPERO International Prospective Register of Ongoing Systematic Reviews (registration number: CRD42015028028). PMID:29070636
Correlates of mobile screen media use among children aged 0-8: a systematic review.

PubMed

Paudel, Susan; Jancey, Jonine; Subedi, Narayan; Leavy, Justine

2017-10-24

This study is a systematic review of the peer-reviewed literature to identify the correlates of mobile screen media use among children aged 8 years and less. Home or community-based studies were included in this review while child care or school-based studies were excluded. Children aged 8 years or less were the study population. Studies that included larger age groups without subgroup analysis specific to the 0-8 years category were excluded. Eight electronic databases were searched for peer-reviewed English language primary research articles published or in press between January 2009 and March 2017 that have studied correlates of mobile screen media use in this age group. Mobile screen media use was the primary outcome measure. Mobile screen media use refers to children's use of mobile screens, such as mobile phones, electronic tablets, handheld computers or personal digital assistants. Thirteen studies meeting the inclusion criteria were identified of which a total of 36 correlates were examined. Older children, children better skilled in using mobile screen media devices, those having greater access to such devices at home and whose parents had high mobile screen media use were more likely to have higher use of mobile screen media devices. No association existed with parent's age, sex and education. Limited research has been undertaken into young children's mobile screen media use and most of the variables have been studied too infrequently for robust conclusions to be reached. Future studies with objective assessment of mobile screen media use and frequent examination of the potential correlates across multiple studies and settings are recommended. This review is registered with PROSPERO International Prospective Register of Ongoing Systematic Reviews (registration number: CRD42015028028). © Article author(s) (or their employer(s) unless otherwise stated in the text of the article) 2017. All rights reserved. No commercial use is permitted unless otherwise expressly granted.
Dynamics driving function: new insights from electron transferring flavoproteins and partner complexes.

PubMed

Toogood, Helen S; Leys, David; Scrutton, Nigel S

2007-11-01

Electron transferring flavoproteins (ETFs) are soluble heterodimeric FAD-containing proteins that function primarily as soluble electron carriers between various flavoprotein dehydrogenases. ETF is positioned at a key metabolic branch point, responsible for transferring electrons from up to 10 primary dehydrogenases to the membrane-bound respiratory chain. Clinical mutations of ETF result in the often fatal disease glutaric aciduria type II. Structural and biophysical studies of ETF in complex with partner proteins have shown that ETF partitions the functions of partner binding and electron transfer between (a) a 'recognition loop', which acts as a static anchor at the ETF-partner interface, and (b) a highly mobile redox-active FAD domain. Together, this enables the FAD domain of ETF to sample a range of conformations, some compatible with fast interprotein electron transfer. This 'conformational sampling' enables ETF to recognize structurally distinct partners, whilst also maintaining a degree of specificity. Complex formation triggers mobility of the FAD domain, an 'induced disorder' mechanism contrasting with the more generally accepted models of protein-protein interaction by induced fit mechanisms. We discuss the implications of the highly dynamic nature of ETFs in biological interprotein electron transfer. ETF complexes point to mechanisms of electron transfer in which 'dynamics drive function', a feature that is probably widespread in biology given the modular assembly and flexible nature of biological electron transfer systems.
Rational In Silico Design of an Organic Semiconductor with Improved Electron Mobility.

PubMed

Friederich, Pascal; Gómez, Verónica; Sprau, Christian; Meded, Velimir; Strunk, Timo; Jenne, Michael; Magri, Andrea; Symalla, Franz; Colsmann, Alexander; Ruben, Mario; Wenzel, Wolfgang

2017-11-01

Organic semiconductors find a wide range of applications, such as in organic light emitting diodes, organic solar cells, and organic field effect transistors. One of their most striking disadvantages in comparison to crystalline inorganic semiconductors is their low charge-carrier mobility, which manifests itself in major device constraints such as limited photoactive layer thicknesses. Trial-and-error attempts to increase charge-carrier mobility are impeded by the complex interplay of the molecular and electronic structure of the material with its morphology. Here, the viability of a multiscale simulation approach to rationally design materials with improved electron mobility is demonstrated. Starting from one of the most widely used electron conducting materials (Alq 3 ), novel organic semiconductors with tailored electronic properties are designed for which an improvement of the electron mobility by three orders of magnitude is predicted and experimentally confirmed. © 2017 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

A review of electronic medical record keeping on mobile medical service trips in austere settings.

PubMed

Dainton, Christopher; Chu, Charlene H

2017-02-01

Electronic medical records (EMRs) may address the need for decision and language support for Western clinicians on mobile medical service trips (MSTs) in low resource settings abroad, while providing improved access to records and data management. However, there has yet to be a review of this emerging technology used by MSTs in low-resource settings. The aim of this study is to describe EMR systems designed specifically for use by mobile MSTs in remote settings, and accordingly, determine new opportunities for this technology to improve quality of healthcare provided by MSTs. A MEDLINE, EMBASE, and Scopus/IEEE search and supplementary Google search were performed for EMR systems specific to mobile MSTs. Information was extracted regarding EMR name, organization, scope of use, platform, open source coding, commercial availability, data integration, and capacity for linguistic and decision support. Missing information was requested by email. After screening of 122 abstracts, two articles remained that discussed deployment of EMR systems in MST settings (iChart, SmartList To Go), and thirteen additional EMR systems were found through the Google search. Of these, three systems (Project Buendia, TEBOW, and University of Central Florida's internally developed EMR) are based on modified versions of Open MRS software, while three are smartphone apps (QuickChart EMR, iChart, NotesFirst). Most of the systems use a local network to manage data, while the remaining systems use opportunistic cloud synchronization. Three (TimmyCare, Basil, and Backpack EMR) contain multilingual user interfaces, and only one (QuickChart EMR) contained MST-specific clinical decision support. There have been limited attempts to tailor EMRs to mobile MSTs. Only Open MRS has a broad user base, and other EMR systems should consider interoperability and data sharing with larger systems as a priority. Several systems include tablet compatibility, or are specifically designed for smartphone, which may be helpful given the environment and low resource context. Results from this review may be useful to non-government organizations (NGOs) considering modernization of their medical records practices as EMR use facilitates research, decreases paper administration costs, and improves perceptions of professionalism; however, most MST-specific EMRs remain in their early stages, and further development and research is required before reaching the stage of widespread adoption. Copyright © 2016 Elsevier Ireland Ltd. All rights reserved.
Terahertz spin current pulses controlled by magnetic heterostructures

NASA Astrophysics Data System (ADS)

Kampfrath, T.; Battiato, M.; Maldonado, P.; Eilers, G.; Nötzold, J.; Mährlein, S.; Zbarsky, V.; Freimuth, F.; Mokrousov, Y.; Blügel, S.; Wolf, M.; Radu, I.; Oppeneer, P. M.; Münzenberg, M.

2013-04-01

In spin-based electronics, information is encoded by the spin state of electron bunches. Processing this information requires the controlled transport of spin angular momentum through a solid, preferably at frequencies reaching the so far unexplored terahertz regime. Here, we demonstrate, by experiment and theory, that the temporal shape of femtosecond spin current bursts can be manipulated by using specifically designed magnetic heterostructures. A laser pulse is used to drive spins from a ferromagnetic iron thin film into a non-magnetic cap layer that has either low (ruthenium) or high (gold) electron mobility. The resulting transient spin current is detected by means of an ultrafast, contactless amperemeter based on the inverse spin Hall effect, which converts the spin flow into a terahertz electromagnetic pulse. We find that the ruthenium cap layer yields a considerably longer spin current pulse because electrons are injected into ruthenium d states, which have a much lower mobility than gold sp states. Thus, spin current pulses and the resulting terahertz transients can be shaped by tailoring magnetic heterostructures, which opens the door to engineering high-speed spintronic devices and, potentially, broadband terahertz emitters.
Problematic mobile phone use of Swiss adolescents: is it linked with mental health or behaviour?

PubMed

Roser, Katharina; Schoeni, Anna; Foerster, Milena; Röösli, Martin

2016-04-01

To investigate the associations between problematic mobile phone use and mental health and behavioural problems in 412 Swiss adolescents owning a mobile phone while controlling for amount of mobile phone use. Problematic mobile phone use was determined by the MPPUS-10 (Mobile Phone Problem Use Scale) and related to health and behavioural problems by means of multivariable regression modelling. MPPUS-10 was 4.7 (95 % CI 1.8, 7.6) units higher in girls than in boys, increased significantly with age and was significantly decreased with increasing educational level of the parents. Furthermore, problematic mobile phone use was associated with impaired psychological well-being, impaired parent and school relationships and more behavioural problems but was not related to peer support and social acceptance. Our study indicates that problematic mobile phone use is associated with external factors such as worse home and school environment and internal factors such as impaired mental health and behavioural problems of the adolescents and thus problematic mobile phone use should be addressed, in particular when dealing with adolescents showing behavioural or emotional problems.
The effect of charged quantum dots on the mobility of a two-dimensional electron gas: How important is the Coulomb scattering?

DOE Office of Scientific and Technical Information (OSTI.GOV)

Kurzmann, A., E-mail: annika.kurzmann@uni-due.de; Beckel, A.; Lorke, A.

2015-02-07

We have investigated the influence of a layer of charged self-assembled quantum dots (QDs) on the mobility of a nearby two-dimensional electron gas (2DEG). Time-resolved transconductance spectroscopy was used to separate the two contributions of the change in mobility, which are: (i) The electrons in the QDs act as Coulomb scatterers for the electrons in the 2DEG. (ii) The screening ability and, hence, the mobility of the 2DEG decreases when the charge carrier density is reduced by the charged QDs, i.e., the mobility itself depends on the charge carrier concentration. Surprisingly, we find a negligible influence of the Coulomb scatteringmore » on the mobility for a 2DEG, separated by a 30 nm tunneling barrier to the layer of QDs. This means that the mobility change is completely caused by depletion, i.e., reduction of the charge carrier density in the 2DEG, which indirectly influences the mobility.« less
Optimized Lateral Flow Immunoassay Reader for the Detection of Infectious Diseases in Developing Countries.

PubMed

Pilavaki, Evdokia; Demosthenous, Andreas

2017-11-20

Detection and control of infectious diseases is a major problem, especially in developing countries. Lateral flow immunoassays can be used with great success for the detection of infectious diseases. However, for the quantification of their results an electronic reader is required. This paper presents an optimized handheld electronic reader for developing countries. It features a potentially low-cost, low-power, battery-operated device with no added optical accessories. The operation of this proof of concept device is based on measuring the reflected light from the lateral flow immunoassay and translating it into the concentration of the specific analyte of interest. Characterization of the surface of the lateral flow immunoassay has been performed in order to accurately model its response to the incident light. Ray trace simulations have been performed to optimize the system and achieve maximum sensitivity by placing all the components in optimum positions. A microcontroller enables all the signal processing to be performed on the device and a Bluetooth module allows transmission of the results wirelessly to a mobile phone app. Its performance has been validated using lateral flow immunoassays with influenza A nucleoprotein in the concentration range of 0.5 ng/mL to 200 ng/mL.
Cooperative problem solving with personal mobile information tools in hospitals.

PubMed

Buchauer, A; Werner, R; Haux, R

1998-01-01

Health-care professionals have a broad range of needs for information and cooperation while working at different points of care (e.g., outpatient departments, wards, and functional units such as operating theaters). Patient-related data and medical knowledge have to be widely available to support high-quality patient care. Furthermore, due to the increased specialization of health-care professionals, efficient collaboration is required. Personal mobile information tools have a considerable potential to realize almost ubiquitous information and collaborative support. They enable to unite the functionality of conventional tools such as paper forms, dictating machines, and pagers into one tool. Moreover, they can extend the support already provided by clinical workstations. An approach is described for the integration of mobile information tools with heterogeneous hospital information systems. This approach includes identification of functions which should be provided on mobile tools. Major functions are the presentation of medical records and reports, electronic mailing to support interpersonal communication, and the provision of editors for structured clinical documentation. To realize those functions on mobile tools, we propose a document-based client-server architecture that enables mobile information tools to interoperate with existing computer-based application systems. Open application systems and powerful, partially wireless, hospital-wide networks are the prerequisites for the introduction of mobile information tools.
78 FR 32689 - Certain Portable Electronic Communications Devices, Including Mobile Phones and Components...

Federal Register 2010, 2011, 2012, 2013, 2014

2013-05-31

..., Including Mobile Phones and Components Thereof Notice of Receipt of Complaint; Solicitation of Comments... Certain Portable Electronic Communications Devices, Including Mobile Phones and Components Thereof, DN... mobile phones and components thereof. The complaint names as respondents HTC Corporation of China and HTC...
Tuning the Electronic Properties, Effective Mass and Carrier Mobility of MoS2 Monolayer by Strain Engineering: First-Principle Calculations

NASA Astrophysics Data System (ADS)

Phuc, Huynh V.; Hieu, Nguyen N.; Hoi, Bui D.; Hieu, Nguyen V.; Thu, Tran V.; Hung, Nguyen M.; Ilyasov, Victor V.; Poklonski, Nikolai A.; Nguyen, Chuong V.

2018-01-01

In this paper, we studied the electronic properties, effective masses, and carrier mobility of monolayer MoS_2 using density functional theory calculations. The carrier mobility was considered by means of ab initio calculations using the Boltzmann transport equation coupled with deformation potential theory. The effects of mechanical biaxial strain on the electronic properties, effective mass, and carrier mobility of monolayer MoS_2 were also investigated. It is demonstrated that the electronic properties, such as band structure and density of state, of monolayer MoS_2 are very sensitive to biaxial strain, leading to a direct-indirect transition in semiconductor monolayer MoS_2. Moreover, we found that the carrier mobility and effective mass can be enhanced significantly by biaxial strain and by lowering temperature. The electron mobility increases over 12 times with a biaxial strain of 10%, while the carrier mobility gradually decreases with increasing temperature. These results are very useful for the future nanotechnology, and they make monolayer MoS_2 a promising candidate for application in nanoelectronic and optoelectronic devices.
75 FR 32984 - Policy on the Retention of Supporting Documents and the Use of Electronic Mobile Communication...

Federal Register 2010, 2011, 2012, 2013, 2014

2010-06-10

...-0168] Policy on the Retention of Supporting Documents and the Use of Electronic Mobile Communication/Tracking Technology in Assessing Motor Carriers' and Commercial Motor Vehicle Drivers' Compliance With the... changes regarding the retention of supporting documents and the use of electronic mobile communication...
An enzymatic biosensor based on three-dimensional ZnO nanotetrapods spatial net modified AlGaAs/GaAs high electron mobility transistors

DOE Office of Scientific and Technical Information (OSTI.GOV)

Song, Yu; Bioengineering Program, Lehigh University, Bethlehem, Pennsylvania 18015; Zhang, Xiaohui

2014-11-24

We designed and constructed three dimensional (3D) zinc oxide Nanotetrapods (T-ZnOs) modified AlGaAs/GaAs high electron mobility transistors (HEMTs) for enzymatic uric acid (UA) detection. The chemical vapor deposition synthesized T-ZnOs was distributed on the gate areas of HEMTs in order to immobilize uricase and improve the sensitivity of the HEMTs. Combining with the high efficiency of enzyme immobilization by T-ZnOs and high sensitivity from HEMT, the as-constructed uricase/T-ZnOs/HEMTs biosensor showed fast response towards UA at ∼1 s, wide linear range from 0.2 nM to 0.2 mM and the low detect limit at 0.2 nM. The results point out an avenue to design electronic devicemore » as miniaturized lab-on-chip device for high sensitive and specific in biomedical and clinical diagnosis applications.« less
77 FR 3386 - Export and Reexport License Requirements for Certain Microwave and Millimeter Wave Electronic...

Federal Register 2010, 2011, 2012, 2013, 2014

2012-01-24

... electronic components. The two components are packaged high electron mobility transistors and packaged..., 2012, FR Doc. 2012- 135). The two components are packaged high electron mobility transistors (HEMT) and...
I've got 99 problems but a phone ain't one: Electronic and mobile health in low and middle income countries.

PubMed

Kumar, Pratap; Paton, Chris; Kirigia, Doris

2016-10-01

Mobile technology is very prevalent in Kenya-mobile phone penetration is at 88% and mobile data subscriptions form 99% of all internet subscriptions. While there is great potential for such ubiquitous technology to revolutionise access and quality of healthcare in low-resource settings, there have been few successes at scale. Implementations of electronic health (e-Health) and mobile health (m-Health) technologies in countries like Kenya are yet to tackle human resource constraints or the political, ethical and financial considerations of such technologies. We outline recent innovations that could improve access and quality while considering the costs of healthcare. One is an attempt to create a scalable clinical decision support system by engaging a global network of specialist doctors and reversing some of the damaging effects of medical brain drain. The other efficiently extracts digital information from paper-based records using low-cost and locally produced tools such as rubber stamps to improve adherence to clinical practice guidelines. By bringing down the costs of remote consultations and clinical audit, respectively, these projects offer the potential for clinics in resource-limited settings to deliver high-quality care. This paper makes a case for continued and increased investment in social enterprises that bridge academia, public and private sectors to deliver sustainable and scalable e-Health and m-Health solutions. Published by the BMJ Publishing Group Limited. For permission to use (where not already granted under a licence) please go to http://www.bmj.com/company/products-services/rights-and-licensing/
Extremely high electron mobility in a phonon-glass semimetal

NASA Astrophysics Data System (ADS)

Ishiwata, S.; Shiomi, Y.; Lee, J. S.; Bahramy, M. S.; Suzuki, T.; Uchida, M.; Arita, R.; Taguchi, Y.; Tokura, Y.

2013-06-01

The electron mobility is one of the key parameters that characterize the charge-carrier transport properties of materials, as exemplified by the quantum Hall effect as well as high-efficiency thermoelectric and solar energy conversions. For thermoelectric applications, introduction of chemical disorder is an important strategy for reducing the phonon-mediated thermal conduction, but is usually accompanied by mobility degradation. Here, we show a multilayered semimetal β-CuAgSe overcoming such a trade-off between disorder and mobility. The polycrystalline ingot shows a giant positive magnetoresistance and Shubnikov de Haas oscillations, indicative of a high-mobility small electron pocket derived from the Ag s-electron band. Ni doping, which introduces chemical and lattice disorder, further enhances the electron mobility up to 90,000 cm2 V-1 s-1 at 10 K, leading not only to a larger magnetoresistance but also a better thermoelectric figure of merit. This Ag-based layered semimetal with a glassy lattice is a new type of promising thermoelectric material suitable for chemical engineering.
Microwave Integrated Circuit Amplifier Designs Submitted to Qorvo for Fabrication with 0.09-micron High Electron Mobility Transistors (HEMTs) using 2-mil Gallium Nitride (GaN) on Silicon Carbide (SiC)

DTIC Science & Technology

2016-03-01

Fabrication with 0.09-µm High-Electron-Mobility Transistors (HEMTs) Using 2-mil Gallium Nitride (GaN) on Silicon Carbide (SiC) by John E Penn...for Fabrication with 0.09-µm High-Electron-Mobility Transistors (HEMTs) using 2-mil Gallium Nitride (GaN) on Silicon Carbide by John E Penn...µm High-Electron-Mobility Transistors (HEMTs) using 2-mil Gallium Nitride (GaN) on Silicon Carbide 5a. CONTRACT NUMBER 5b. GRANT NUMBER 5c
Integration of a mobile-integrated therapy with electronic health records: lessons learned.

PubMed

Peeples, Malinda M; Iyer, Anand K; Cohen, Joshua L

2013-05-01

Responses to the chronic disease epidemic have predominantly been standardized in their approach to date. Barriers to better health outcomes remain, and effective management requires patient-specific data and disease state knowledge be presented in methods that foster clinical decision-making and patient self-management. Mobile technology provides a new platform for data collection and patient-provider communication. The mobile device represents a personalized platform that is available to the patient on a 24/7 basis. Mobile-integrated therapy (MIT) is the convergence of mobile technology, clinical and behavioral science, and scientifically validated clinical outcomes. In this article, we highlight the lessons learned from functional integration of a Food and Drug Administration-cleared type 2 diabetes MIT into the electronic health record (EHR) of a multiphysician practice within a large, urban, academic medical center. In-depth interviews were conducted with integration stakeholder groups: mobile and EHR software and information technology teams, clinical end users, project managers, and business analysts. Interviews were summarized and categorized into lessons learned using the Architecture for Integrated Mobility® framework. Findings from the diverse stakeholder group of a MIT-EHR integration project indicate that user workflow, software system persistence, environment configuration, device connectivity and security, organizational processes, and data exchange heuristics are key issues that must be addressed. Mobile-integrated therapy that integrates patient self-management data with medical record data provides the opportunity to understand the potential benefits of bidirectional data sharing and reporting that are most valuable in advancing better health and better care in a cost-effective way that is scalable for all chronic diseases. © 2013 Diabetes Technology Society.
Boost the electron mobility of solution-grown organic single crystals via reducing the amount of polar solvent residues

DOE PAGES

Xue, Guobiao; Xin, Huolin L.; Wu, Jiake; ...

2015-10-29

Enhancing electron transport to match with the development in hole transport is critical for organic electronics in the future. As electron motion is susceptible to extrinsic factors, seeking these factors and avoiding their negative effects have become the central challenge. Here, the existence of polar solvent residues in solution-grown single-crystals of 6,13-bis(triisopropylsilylethynyl)-5,7,12,14-tetraazapentacene is identified as a factor detrimental to electron motion. Field-effect transistors of the crystals exhibit electron mobility boosted by about 60% after the residues are removed. The average electron mobility reaches up to 8.0 ± 2.2 cm 2 V –1 s –1 with a highest value of 13.3more » cm 2 V –1 s –1; these results are significantly higher than those obtained previously for the same molecule (1.0–5.0 cm 2 V –1 s –1). Furthermore, the achieved mobility is also higher than the maximum reported electron mobility for organic materials (11 cm 2 V –1 s –1). As a result, this work should greatly accelerate the advancement of organic electron-transporting materials.« less
Enhanced mobility in vertically scaled N-polar high-electron-mobility transistors using GaN/InGaN composite channels

NASA Astrophysics Data System (ADS)

Li, Haoran; Wienecke, Steven; Romanczyk, Brian; Ahmadi, Elaheh; Guidry, Matthew; Zheng, Xun; Keller, Stacia; Mishra, Umesh K.

2018-02-01

A GaN/InGaN composite channel design for vertically scaled N-polar high-electron-mobility transistor (HEMT) structures is proposed and demonstrated by metal-organic chemical vapor deposition. In a conventional N-polar HEMT structure, as the channel thickness (tch) decreases, the sheet charge density (ns) decreases, the electric field in the channel increases, and the centroid of the two-dimensional electron gas (2DEG) moves towards the back-barrier/channel interface, resulting in stronger scattering and lower electron mobility (μ). In this study, a thin InGaN layer was introduced in-between the channel and the AlGaN cap to increase the 2DEG density and reduce the electric field in the channel and therefore increase the electron mobility. The dependence of μ on the InGaN thickness (tInGaN) and the indium composition (xIn) was investigated for different channel thicknesses. With optimized tInGaN and xIn, significant improvements in electron mobility were observed. For a 6 nm channel HEMT structure, the electron mobility increased from 606 to 1141 cm2/(V.s) when the 6 nm thick pure GaN channel was replaced by the 4 nm GaN/2 nm In0.1Ga0.9N composite channel.
Theoretical prediction of high carrier mobility in single-walled black phosphorus nanotubes

NASA Astrophysics Data System (ADS)

Li, Q. F.; Wang, H. F.; Yang, C. H.; Li, Q. Q.; Rao, W. F.

2018-05-01

One-dimensional semiconductors are promising materials for high-performance nanoscale devices. Using the first-principles calculations combined with deformation potential approximation, we study the electronic structures and carrier transport properties of black phosphorus nanotubes (BPNTs). It is found that both armchair and zigzag BPNTs with diameter 13.5-18.5 Å are direct bandgap semiconductors. At a similar diameter, the carrier mobility of zigzag BPNT is one order of magnitude larger than that of armchair BPNT. For armchair BPNTs, the electron mobility is about 90.70-155.33 cm2 V-1 s-1 at room temperature, which is about three times of its hole counterpart. For zigzag BPNTs, the maximum mobility can reach 2.87 ×103 cm2 V-1 s-1. Furthermore, the electronic properties can be effectively tuned by the strain. For zigzag (0,13) nanotube, there is a direct-to-indirect band gap transition at a tensile strain of about 6%. Moreover, the electron mobility is boosted sharply by one order of magnitude by applying the compressive or tensile strain. The electron mobility increases to 14.05 ×103 cm2 V-1 s-1 at a tensile strain of 9%. Our calculations highlight the tunable electronic properties and superior carrier mobility of BPNTs that are promising for interesting applications in future nano-electronic devices.
78 FR 37220 - Proposed Information Collection Request; Comment Request; EPA-ICR No. 1774.05-Mobile Air...

Federal Register 2010, 2011, 2012, 2013, 2014

2013-06-20

... appropriate automated electronic, mechanical, or other technological collection techniques or other forms of... substances (ODS) are replaced by alternatives that reduce overall risks to human health and the environment... specific use, typically with some condition or limit to minimize risks to human health and the environment...
Itinerant electrons in the Coulomb phase

NASA Astrophysics Data System (ADS)

Jaubert, L. D. C.; Piatecki, Swann; Haque, Masudul; Moessner, R.

2012-02-01

We study the interplay between magnetic frustration and itinerant electrons. For example, how does the coupling to mobile charges modify the properties of a spin liquid, and does the underlying frustration favor insulating or conducting states? Supported by Monte Carlo simulations, our goal is in particular to provide an analytical picture of the mechanisms involved. The models under consideration exhibit Coulomb phases in two and three dimensions, where the itinerant electrons are coupled to the localized spins via double exchange interactions. Because of the Hund coupling, magnetic loops naturally emerge from the Coulomb phase and serve as conducting channels for the mobile electrons, leading to doping-dependent rearrangements of the loop ensemble in order to minimize the electronic kinetic energy. At low electron density ρ, the double exchange coupling mainly tends to segment the very long loops winding around the system into smaller ones while it gradually lifts the extensive degeneracy of the Coulomb phase with increasing ρ. For higher doping, the results are strongly lattice dependent, displaying loop crystals with a given loop length for some specific values of ρ. By varying ρ, they can melt into different mixtures of these loop crystals, recovering extensive degeneracy in the process. Finally, we contrast this to the qualitatively different behavior of analogous models on kagome or triangular lattices.

Direct detection of fibrinogen in human plasma using electric-double-layer gated AlGaN/GaN high electron mobility transistors

NASA Astrophysics Data System (ADS)

Regmi, Abiral; Sarangadharan, Indu; Chen, Yen-Wen; Hsu, Chen-Pin; Lee, Geng-Yen; Chyi, Jen-Inn; Shiesh, Shu-Chu; Lee, Gwo-Bin; Wang, Yu-Lin

2017-08-01

Fibrinogen found in blood plasma is an important protein biomarker for potentially fatal diseases such as cardiovascular diseases. This study focuses on the development of an assay to detect plasmatic fibrinogen using electrical double layer gated AlGaN/GaN high electron mobility transistor biosensors without complex sample pre-treatment methods used in the traditional assays. The test results in buffer solution and clinical plasma samples show high sensitivity, specificity, and dynamic range. The sensor exhibits an ultra-low detection limit of 0.5 g/l and a detection range of 0.5-4.5 g/l in 1× PBS with 1% BSA. The concentration dependent sensor signal in human serum samples demonstrates the specificity to fibrinogen in a highly dense matrix of background proteins. The sensor does not require complicated automation, and quantitative results are obtained in 5 min with <5 μl sample volume. This sensing technique is ideal for speedy blood based diagnostics such as POC (point of care) tests, homecare tests, or personalized healthcare.
Passion, Relational Mobility, and Proof of Commitment: A Comparative Socio-Ecological Analysis of an Adaptive Emotion in a Sexual Market.

PubMed

Yamada, Junko; Kito, Mie; Yuki, Masaki

2017-01-01

Although monogamy, the exclusive bonding with a specific partner, is one characteristic of modern human mating, long-term romantic relationships inherently possess the commitment problem, which is the conflict between maintaining a relationship with a certain partner and seeking attractive alternatives. Frank has argued that love and passion help solve this problem because they make individuals commit voluntarily to the relationship, leading the other party to also be committed with less concern over being cheated on or rejected. Combining this idea with the comparative socio-ecological approach, we hypothesize that passion will be more pronounced in social environments in which people have greater freedom to choose and replace their partners (i.e., high relational mobility) than in societies in which relationships tend to be more stable and hard to change (i.e., low relational mobility). To test this hypothesis, we compared Americans (living in a society with high relational mobility) and Japanese (living in a society with low relational mobility). As predicted, Americans were more passionate toward their romantic partners than Japanese, and this cultural difference was partially explained by the levels of perceived relational mobility in participants' local ecology. Moreover, more intense passion was found to lead to greater commitment behaviors in both societies. The importance of taking socioecological factors into consideration for the theory of the adaptive function of interpersonal emotions is also discussed.
Charge carrier mobility and electronic properties of Al(Op)3: impact of excimer formation

PubMed Central

Friederich, Pascal; Schäfer, Bernhard; Fattori, Valeria; Sun, Xiangnan; Strunk, Timo; Meded, Velimir; Hueso, Luis E; Wenzel, Wolfgang; Ruben, Mario

2015-01-01

Summary We have studied the electronic properties and the charge carrier mobility of the organic semiconductor tris(1-oxo-1H-phenalen-9-olate)aluminium(III) (Al(Op)3) both experimentally and theoretically. We experimentally estimated the HOMO and LUMO energy levels to be −5.93 and −3.26 eV, respectively, which were close to the corresponding calculated values. Al(Op)3 was successfully evaporated onto quartz substrates and was clearly identified in the absorption spectra of both the solution and the thin film. A structured steady state fluorescence emission was detected in solution, whereas a broad, red-shifted emission was observed in the thin film. This indicates the formation of excimers in the solid state, which is crucial for the transport properties. The incorporation of Al(Op)3 into organic thin film transistors (TFTs) was performed in order to measure the charge carrier mobility. The experimental setup detected no electron mobility, while a hole mobility between 0.6 × 10−6 and 2.1 × 10−6 cm2·V−1·s−1 was measured. Theoretical simulations, on the other hand, predicted an electron mobility of 9.5 × 10−6 cm2·V−1·s−1 and a hole mobility of 1.4 × 10−4 cm2·V−1·s−1. The theoretical simulation for the hole mobility predicted an approximately one order of magnitude higher hole mobility than was observed in the experiment, which is considered to be in good agreement. The result for the electron mobility was, on the other hand, unexpected, as both the calculated electron mobility and chemical common sense (based on the capability of extended aromatic structures to efficiently accept and delocalize additional electrons) suggest more robust electron charge transport properties. This discrepancy is explained by the excimer formation, whose inclusion in the multiscale simulation workflow is expected to bring the theoretical simulation and experiment into agreement. PMID:26171287
Patient monitoring in mobile health: opportunities and challenges.

PubMed

Mohammadzadeh, Niloofar; Safdari, Reza

2014-01-01

In most countries chronic diseases lead to high health care costs and reduced productivity of people in society. The best way to reduce costs of health sector and increase the empowerment of people is prevention of chronic diseases and appropriate health activities management through monitoring of patients. To enjoy the full benefits of E-health, making use of methods and modern technologies is very important. This literature review articles were searched with keywords like Patient monitoring, Mobile Health, and Chronic Disease in Science Direct, Google Scholar and Pub Med databases without regard to the year of publications. Applying remote medical diagnosis and monitoring system based on mobile health systems can help significantly to reduce health care costs, correct performance management particularly in chronic disease management. Also some challenges are in patient monitoring in general and specific aspects like threats to confidentiality and privacy, technology acceptance in general and lack of system interoperability with electronic health records and other IT tools, decrease in face to face communication between doctor and patient, sudden interruptions of telecommunication networks, and device and sensor type in specific aspect. It is obvious identifying the opportunities and challenges of mobile technology and reducing barriers, strengthening the positive points will have a significant role in the appropriate planning and promoting the achievements of the health care systems based on mobile and helps to design a roadmap for improvement of mobile health.
Fluorescent protein integrated white LEDs for displays

NASA Astrophysics Data System (ADS)

Press, Daniel Aaron; Melikov, Rustamzhon; Conkar, Deniz; Nur Firat-Karalar, Elif; Nizamoglu, Sedat

2016-11-01

The usage time of displays (e.g., TVs, mobile phones, etc) is in general shorter than their functional life time, which worsens the electronic waste (e-waste) problem around the world. The integration of biomaterials into electronics can help to reduce the e-waste problem. In this study, we demonstrate fluorescent protein integrated white LEDs to use as a backlight source for liquid crystal (LC) displays for the first time. We express and purify enhanced green fluorescent protein (eGFP) and monomeric Cherry protein (mCherry), and afterward we integrate these proteins as a wavelength-converter on a blue LED chip. The protein-integrated backlight exhibits a high luminous efficacy of 248 lm/Wopt and the area of the gamut covers 80% of the NTSC color gamut. The resultant colors and objects in the image on the display can be well observed and distinguished. Therefore, fluorescent proteins show promise for display applications.
Programmable graphene doping via electron beam irradiation.

PubMed

Zhou, Yangbo; Jadwiszczak, Jakub; Keane, Darragh; Chen, Ying; Yu, Dapeng; Zhang, Hongzhou

2017-06-29

Graphene is a promising candidate to succeed silicon based devices, and the conventional strategies for fabrication and testing of graphene-based electronics often utilise an electron beam. Here, we report on a systematic study of the effect of electron beam exposure on graphene devices. We realise reversible doping of on-chip graphene using a focused electron beam. Our results demonstrate site-specific control of carrier type and concentration achievable by modulating the charge distribution in the substrate. The effect of substrate-embedded charges on carrier mobility and conductivity of graphene is studied, with a dielectric screening model proposed to explain the effective n-type and p-type doping produced at different beam energies. Multiple logic operations are thus implemented in a single graphene sheet by using site-specific e-beam irradiation. We extend the phenomenon to MoS 2 , generalising it to conductive two-dimensional materials. Our results are of importance to imaging, in situ characterisation and lithographic techniques employed to investigate 2D materials.
Tuning charge transport in pentacene thin-film transistors using the strain-induced electron-phonon coupling modification

NASA Astrophysics Data System (ADS)

Lin, Yow-Jon; Chang, Hsing-Cheng; Liu, Day-Shan

2015-03-01

Tuning charge transport in the bottom-contact pentacene-based organic thin-film transistors (OTFTs) using a MoO x capping layer that serves to the electron-phonon coupling modification is reported. For OTFTs with a MoO x front gate, the enhanced field-effect carrier mobility is investigated. The time domain data confirm the electron-trapping model. To understand the origin of a mobility enhancement, an analysis of the temperature-dependent Hall-effect characteristics is presented. Similarly, the Hall-effect carrier mobility was dramatically increased by capping a MoO x layer on the pentacene front surface. However, the carrier concentration is not affected. The Hall-effect carrier mobility exhibits strong temperature dependence, indicating the dominance of tunneling (hopping) at low (high) temperatures. A mobility enhancement is considered to come from the electron-phonon coupling modification that results from the contribution of long-lifetime electron trapping.
Organic High Electron Mobility Transistors Realized by 2D Electron Gas.

PubMed

Zhang, Panlong; Wang, Haibo; Yan, Donghang

2017-09-01

A key breakthrough in inorganic modern electronics is the energy-band engineering that plays important role to improve device performance or develop novel functional devices. A typical application is high electron mobility transistors (HEMTs), which utilizes 2D electron gas (2DEG) as transport channel and exhibits very high electron mobility over traditional field-effect transistors (FETs). Recently, organic electronics have made very rapid progress and the band transport model is demonstrated to be more suitable for explaining carrier behavior in high-mobility crystalline organic materials. Therefore, there emerges a chance for applying energy-band engineering in organic semiconductors to tailor their optoelectronic properties. Here, the idea of energy-band engineering is introduced and a novel device configuration is constructed, i.e., using quantum well structures as active layers in organic FETs, to realize organic 2DEG. Under the control of gate voltage, electron carriers are accumulated and confined at quantized energy levels, and show efficient 2D transport. The electron mobility is up to 10 cm 2 V -1 s -1 , and the operation mechanisms of organic HEMTs are also argued. Our results demonstrate the validity of tailoring optoelectronic properties of organic semiconductors by energy-band engineering, offering a promising way for the step forward of organic electronics. © 2017 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.
76 FR 23923 - Hazardous Materials: Restricting the Use of Cellular Phones by Drivers of Commercial Motor...

Federal Register 2010, 2011, 2012, 2013, 2014

2011-04-29

... associated with the use of cellular (mobile) phones and electronic devices while operating a commercial motor... mobile communication device that falls under or uses any commercial mobile radio service, as defined in... restricting the use of mobile telephones and other distracting electronic devices by railroad operating...
Pre and post-amputation mobility of trans-tibial amputees: correlation to medical problems, age and mortality.

PubMed

Johnson, V J; Kondziela, S; Gottschalk, F

1995-12-01

This retrospective study compares pre and post-amputation mobility and the influence of age and associated medical problems. Data from the charts of 120 male patients who underwent unilateral trans-tibial (below-knee) amputation at the Dallas Veteran's Administration Hospital between June, 1983 and October, 1991, were collected and analyzed. Mobility was assessed with a six level scale developed by Volpicelli et al. (1983). The presence of cardiac disease, pulmonary disease (COPD), peripheral vascular disease (PVD), diabetes mellitus, degenerative joint disease, blindness, cerebral vascular accident (CVA), and age are correlated with changes in mobility after amputation. Older patients had more medical problems and lower post-amputation scores Individual medical problems did not influence mobility scores, but the presence of COPD and PVD lowered pre-amputation mobility scores. Cardiac disease and diabetes mellitus influenced post-amputation mobility scores by lowering them, either together or individually. Regardless of age, however, patients with more medical problems were poor ambulators. The cause of amputation per se did not influence mobility scores.
Social Welfare Control in Mobile Crowdsensing Using Zero-Determinant Strategy.

PubMed

Hu, Qin; Wang, Shengling; Bie, Rongfang; Cheng, Xiuzhen

2017-05-03

As a promising paradigm, mobile crowdsensing exerts the potential of widespread sensors embedded in mobile devices. The greedy nature of workers brings the problem of low-quality sensing data, which poses threats to the overall performance of a crowdsensing system. Existing works often tackle this problem with additional function components. In this paper, we systematically formulate the problem into a crowdsensing interaction process between a requestor and a worker, which can be modeled by two types of iterated games with different strategy spaces. Considering that the low-quality data submitted by the workers can reduce the requestor's payoff and further decrease the global income, we turn to controlling the social welfare in the games. To that aim, we take advantage of zero-determinant strategy, based on which we propose two social welfare control mechanisms under both game models. Specifically, we consider the requestor as the controller of the games and, with proper parameter settings for the to-be-adopted zero-determinant strategy, social welfare can be optimized to the desired level no matter what strategy the worker adopts. Simulation results demonstrate that the requestor can achieve the maximized social welfare and keep it stable by using our proposed mechanisms.
Social Welfare Control in Mobile Crowdsensing Using Zero-Determinant Strategy

PubMed Central

Hu, Qin; Wang, Shengling; Bie, Rongfang; Cheng, Xiuzhen

2017-01-01

As a promising paradigm, mobile crowdsensing exerts the potential of widespread sensors embedded in mobile devices. The greedy nature of workers brings the problem of low-quality sensing data, which poses threats to the overall performance of a crowdsensing system. Existing works often tackle this problem with additional function components. In this paper, we systematically formulate the problem into a crowdsensing interaction process between a requestor and a worker, which can be modeled by two types of iterated games with different strategy spaces. Considering that the low-quality data submitted by the workers can reduce the requestor’s payoff and further decrease the global income, we turn to controlling the social welfare in the games. To that aim, we take advantage of zero-determinant strategy, based on which we propose two social welfare control mechanisms under both game models. Specifically, we consider the requestor as the controller of the games and, with proper parameter settings for the to-be-adopted zero-determinant strategy, social welfare can be optimized to the desired level no matter what strategy the worker adopts. Simulation results demonstrate that the requestor can achieve the maximized social welfare and keep it stable by using our proposed mechanisms. PMID:28467370
Thermal Investigation of Three-Dimensional GaN-on-SiC High Electron Mobility Transistors

DTIC Science & Technology

2017-07-01

AFRL-RY-WP-TR-2017-0143 THERMAL INVESTIGATION OF THREE- DIMENSIONAL GaN-on-SiC HIGH ELECTRON MOBILITY TRANSISTORS Qing Hao The University of Arizona...To) July 2017 Final 08 April 2015 – 10 April 2017 4. TITLE AND SUBTITLE THERMAL INVESTIGATION OF THREE-DIMENSIONAL GaN-on-SiC HIGH ELECTRON MOBILITY...used in many DoD applications, including integrated radio frequency (RF) amplifiers and power electronics . However, inherent inefficiencies in
Metals bioleaching from electronic waste by Chromobacterium violaceum and Pseudomonads sp.

PubMed

Pradhan, Jatindra Kumar; Kumar, Sudhir

2012-11-01

These days, electronic waste needs to be taken into consideration due to its materials content, but due to the heterogeneity of the metals present, reprocessing of electronic waste is quite limited. The bioleaching of metals from electronic waste was investigated by using cyanogenic bacterial strains (Chromobacterium violaceum, Pseudomonas aeruginosa and Pseudomonas fluorescens). A two-step bioleaching process was followed under cyanide-forming conditions for maximum metals mobilization. Both single and mixed cultures of cyanogenic bacteria were able to mobilize metals from electronic waste with different efficiencies. In all the flasks in which high metal mobilizations were observed, the consequent biomass productions were also high. Pseudomonas aeruginosa was applied in the bioleaching process for the first time and this achieved its bioleaching ability of mobilization of metals from electronic waste. Chromobacterium violaceum as a single culture and a mixture of C. violaceum and P. aeruginosa exhibited maximum metal mobilization. Chromobacterium violaceum was capable of leaching more than 79, 69, 46, 9 and 7% of Cu, Au, Zn, Fe and Ag, respectively at an electronic waste concentration of 1% w/v. Moreover, the mixture of C. violaceum and P. aeruginosa exhibited metals leaching of more than 83, 73, 49, 13 and 8% of total Cu, Au, Zn, Fe, and Ag, respectively. Precious metals were mobilized through bioleaching which might be considered as an industrial application for recycling of electronic waste in the near future.
Electron-polar optical phonon scattering suppression and mobility enhancement in wurtzite heterostructures

NASA Astrophysics Data System (ADS)

Pokatilov, E. P.; Nika, D. L.; Zincenco, N. D.; Balandin, A. A.

2007-12-01

We have shown theoretically that the electron mobility in wurtzite AlN/GaN/AlN heterostructures can be enhanced by compensating the built-in electric field with the externally applied perpendicular electric field and by introducing a shallow InxGa1-xN channel in the center of GaN potential well. It was found that two- to fivefold increase of the room temperature electron mobility can be achieved. The tuning of the electron mobility with the external electric field or InxGa1-xN channel can be useful for the design of GaN-based field-effect transistors and optoelectronic devices.
Electronic transport in smectic liquid crystals

NASA Astrophysics Data System (ADS)

Shiyanovskaya, I.; Singer, K. D.; Twieg, R. J.; Sukhomlinova, L.; Gettwert, V.

2002-04-01

Time-of-flight measurements of transient photoconductivity have revealed bipolar electronic transport in phenylnaphthalene and biphenyl liquid crystals (LC), which exhibit several smectic mesophases. In the phenylnaphthalene LC, the hole mobility is significantly higher than the electron mobility and exhibits different temperature and phase behavior. Electron mobility in the range ~10-5 cm2/V s is temperature activated and remains continuous at the phase transitions. However, hole mobility is nearly temperature independent within the smectic phases, but is very sensitive to smectic order, 10-3 cm2/V s in the smectic-B (Sm-B) and 10-4 cm2/V s in the smectic-A (Sm-A) mesophases. The different behavior for holes and electron transport is due to differing transport mechanisms. The electron mobility is apparently controlled by rate-limiting multiple shallow trapping by impurities, but hole mobility is not. To explain the lack of temperature dependence for hole mobility within the smectic phases we consider two possible polaron transport mechanisms. The first mechanism is based on the hopping of Holstein small polarons in the nonadiabatic limit. The polaron binding energy and transfer integral values, obtained from the model fit, turned out to be sensitive to the molecular order in smectic mesophases. A second possible scenario for temperature-independent hole mobility involves the competion between two different polaron mechanisms involving so-called nearly small molecular polarons and small lattice polarons. Although the extracted transfer integrals and binding energies are reasonable and consistent with the model assumptions, the limited temperature range of the various phases makes it difficult to distinguish between any of the models. In the biphenyl LCs both electron and hole mobilities exhibit temperature activated behavior in the range of 10-5 cm2/V s without sensitivity to the molecular order. The dominating transport mechanism is considered as multiple trapping in the impurity sites. Temperature-activated mobility was treated within the disorder formalism, and activation energy and width of density of states have been calculated.
Electronic Excitation in Molecular Collisions: Structural, Dynamic and Kinetic Considerations.

DTIC Science & Technology

1981-08-01

electronically excited species are examined. The problem is studied both in general terms (i.e., the development of the required theoretical framework ) and in application to specific systems. (Author)
Electronic Excitation in Molecular Collisions: Structural, Dynamic and Kinetic Considerations.

DTIC Science & Technology

1980-09-01

electronically excited species are examined. The problem is studied both in general terms (i.e., the development of the required theoretical framework ) and in application to specific systems. (Author)
Electronic Excitation in Molecular Collisions: Structural, Dynamic and Kinetic Considerations.

DTIC Science & Technology

1979-09-01

electronically excited species are examined. The problem is studied both in general terms (i.e., the development of the required theoretical framework ) and in application to specific systems. (Author)
Electronic Excitation in Molecular Collisions: Structural, Dynamic and Kinetic Considerations.

DTIC Science & Technology

electronically excited specied are examined. The problem is studied both in general terms (i.e., the development of the required theoretical framework ) and in application to specific systems. (Author)

Bipolar molecular composites: a new class of high-electron-mobility organic solids

NASA Astrophysics Data System (ADS)

Lin, Liang-Bih; Jenekhe, Samson A.; Borsenberger, Paul M.

1997-10-01

We describe high electron mobility in organic solids in the form of bipolar molecular composites of N,N'-bis(1,2-dimethylpropyl)-1,4,5,8-naphthalenetetracarboxylic diimide (NTDI) and tri-p-tolylaniine (TTA). The electron mobility in the NTDI/TTA composites is ~2 x 10 cm2/Vs, which is a factor of 4 to 6 higher than in pure NTDI and isone of the highest values reported for disordered organic solids. The field and temperature dependencies of the charge mobility can be described using the disorder formalism due to Bassler and co-workers, which provides an estimation of the energy width σ of the hopping site manifold. Analysis of the data gave σ=0.081 and 0.060 eV for the electron and hole mobilities in a NTDI/TTA composite of 0.5510.45 molar ratio. The energetic disorder for electron transport in the bipolar composites is substantially lower than for pure NTDI, which is 0.093 eV. The results suggest that the observed enhancement arises from a substantial reduction of energetic disorder in the electron transport manifold of the bipolar composites. The reduction of energetic disorder may be due to intermolecular charge transfer between NTDI and TTA. Such a charge transfer could stabilize the electron transport manifold by better charge delocalization, and consequently, less energetic disorder. Another possible reason for the observed enhanced electron mobility is the reduction of NTDI dimers that can act as carrier traps by the presence of TTA molecules in the bipolar composites. These results also suggest that bipolar composites represent a promising new class of high electron mobility organic solids.
Association of mobile phone radiation with fatigue, headache, dizziness, tension and sleep disturbance in Saudi population.

PubMed

Al-Khlaiwi, Thamir; Meo, Sultan A

2004-06-01

The widespread use of mobile phones has been increased over the past decade; they are now an essential part of business, commerce and society. The use of mobile phones can cause health problems. Therefore, the aim of the present study is to investigate the association of using mobile phones with fatigue, headache, dizziness, tension and sleep disturbance in the Saudi population and provide health and social awareness in using these devices. This study was conducted in the Department of Physiology, College of Medicine, King Saud University, Riyadh, Kingdom of Saudi Arabia during the year 2002 to 2003. In the present study, a total of 437 subjects (55.1% male and 39.9% female) were invited, they have and had been using mobile phones. A questionnaire was distributed regarding detailed history and association of mobile phones with health hazards. The results of the present study showed an association between the use of mobile phones and health hazards. The overall mean percentage for these clinical findings in all groups were headache (21.6%), sleep disturbance (4.%), tension (3.9%), fatigue (3%) and dizziness (2.4%). Based on the results of the present study, we conclude that the use of mobile phones is a risk factor for health hazards and suggest that long term or excessive use of mobile phones should be avoided by health promotion activities such as group discussions, public presentations and through electronic and print media sources.
Problems related to the integration of fault tolerant aircraft electronic systems

NASA Technical Reports Server (NTRS)

Bannister, J. A.; Adlakha, V.; Triyedi, K.; Alspaugh, T. A., Jr.

1982-01-01

Problems related to the design of the hardware for an integrated aircraft electronic system are considered. Taxonomies of concurrent systems are reviewed and a new taxonomy is proposed. An informal methodology intended to identify feasible regions of the taxonomic design space is described. Specific tools are recommended for use in the methodology. Based on the methodology, a preliminary strawman integrated fault tolerant aircraft electronic system is proposed. Next, problems related to the programming and control of inegrated aircraft electronic systems are discussed. Issues of system resource management, including the scheduling and allocation of real time periodic tasks in a multiprocessor environment, are treated in detail. The role of software design in integrated fault tolerant aircraft electronic systems is discussed. Conclusions and recommendations for further work are included.
Highly Mobile Students: Educational Problems and Possible Solutions. ERIC/CUE Digest, Number 73.

ERIC Educational Resources Information Center

ERIC Clearinghouse on Urban Education, New York, NY.

The following two types of student mobility stand out as causing educational problems: (1) inner-city mobility, which is prompted largely by fluctuations in the job market; and (2) intra-city mobility, which is caused by upward mobility or by poverty and homelessness. Most research indicates that high mobility negatively affects student…
17 CFR 23.202 - Daily trading records.

Code of Federal Regulations, 2014 CFR

2014-04-01

..., instant messaging, chat rooms, electronic mail, mobile device, or other digital or electronic media. Such...; (ii) Moneys borrowed and moneys loaned; (iii) The daily calculation of the value of each outstanding... rooms, electronic mail, mobile device, or other digital or electronic media; (2) Reliable timing data...
17 CFR 23.202 - Daily trading records.

Code of Federal Regulations, 2013 CFR

2013-04-01

..., instant messaging, chat rooms, electronic mail, mobile device, or other digital or electronic media. Such...; (ii) Moneys borrowed and moneys loaned; (iii) The daily calculation of the value of each outstanding... rooms, electronic mail, mobile device, or other digital or electronic media; (2) Reliable timing data...
Engineering potential for lunar missions after Apollo.

NASA Technical Reports Server (NTRS)

Burke, J. D.

1972-01-01

The need for continuing post-Apollo lunar research is defined by outlining problems in stellar, planetary, biological, and social evolution which require specific studies of the moon. Engineering capabilities existing immediately after the Apollo program are described in the areas of launch vehicles and spacecraft, lunar surface mobility, instrumentation, and communications.
Analysis of Proton Radiation Effects on Gallium Nitride High Electron Mobility Transistors

DTIC Science & Technology

2017-03-01

energy levels on a GaN-on-silicon high electron mobility transistor was created. Based on physical results of 2.0-MeV protons irradiation to fluence...and the physical device at 2.0-MeV proton irradiation , predictions were made for 5.0, 10.0, 20.0 and 40.0-MeV proton irradiation . The model generally...nitride, high electron mobility transistor, electronics, 2 MeV proton irradiation , radiation effects 15. NUMBER OF PAGES 87 16. PRICE CODE 17. SECURITY
Chemistry at the dirac point of graphene

NASA Astrophysics Data System (ADS)

Sarkar, Santanu

Graphene holds great potential as an electronic material because of its excellent transport properties, which derive from its unique Fermi surface and ballistic conductance. It exhibits extremely high mobility [~250,000 cm*2/(V*s)]. Despite its extraordinary properties, the absence of a band-gap in graphene makes it unsuitable for its use as an active element in conventional field effect transistors (FETs). Another problem with pristine graphene is its lack of solution processability, which inhibits it applications in numerous fields such as printed electronics, transparent conductors, nano-biodevices, and thin film technologies involving fuel cells, capacitors and solar cells. My thesis is focused on addressing theses issue by application of covalent chemistry on graphene. We have applied the Kolbe electro-oxidation strategy to achieve an efficient quasi-reversible electrochemical grafting of the naphthylmethyl radicals to graphene. The method facilitates reversible bandgap engineering in graphene and preparation of electrochemically erasable organic dielectric films. We have discovered that the zero-band-gap electronic structure of graphene enables it to function as either the diene or the dienophile in the Diels-Alder (DA) reaction, and this versatile synthetic method offers a powerful strategy for the reversible modification of the electronic properties of graphene under very mild conditions. We show that the application of the Diels-Alder (DA) chemistry to graphene, which is capable of simultaneous formation of a pair of sp3-carbon centers (balanced divacancies) in graphene, can selectively produce DA-modified graphene FET devices with mobility between 1,000-6,000 cm2V-1s-1 (with a variable range hopping transport mechanism). Most of the covalent chemistry applied on graphene leads to the change in hybridization of graphene sp2 carbon to sp3 (destructive hybridization) and the FET devices based on such covalently modified graphene shows a drastic reduction of device mobility. To this end, we find that the organometallic hexahapto metal complexation chemistry of graphene, in which the graphene pi-band constructively hybridizes with the vacant d-orbitals of transition metals, allows the fabrication of field effect devices which retain a high degree of the mobility with enhanced on-off ratio. In summary, we find that the singular electronic structure of graphene at the Dirac point governs the chemical reactivity of graphene and this chemistry will play a vital role in propelling graphene to assume its role as the next generation electronic material beyond silicon.
Theoretical Characterization of Charge Transport in Chromia (α-Cr2O3)

DOE Office of Scientific and Technical Information (OSTI.GOV)

Iordanova, Nellie I.; Dupuis, Michel; Rosso, Kevin M.

2005-08-15

Transport of conduction electrons and holes through the lattice of ?-Cr2O3 (chromia) is modeled as a valence alternation of chromium cations using ab initio electronic structure calculations and electron transfer theory. In the context of the small polaron model, a cluster approach was used to compute quantities controlling the mobility of localized electrons and holes, i.e. the reorganization energy and the electronic coupling matrix element that enter Marcus? theory. The calculation of the electronic coupling followed the Generalized Mulliken-Hush approach and the quasi-diabatic method using the complete active space self-consistent field (CASSCF) method. Our findings indicate that hole mobility ismore » more than three orders of magnitude larger than electron mobility in both (001) and [001] lattice directions. The difference arises mainly from the larger internal reorganization energy calculated for electron transport relative to hole transport processes while electronic couplings have similar magnitudes. The much larger hole mobility vs electron mobility in ?-Cr2O3 is in contrast to similar hole and electron mobility in hematite ?-Fe2O3 previously calculated. Our calculations also indicate that the electronic coupling for all charge transfer processes of interest is smaller than for the corresponding processes in hematite. This variation is attributed to weaker interaction between the metal 3d states and the O(2p) states in chromia than in hematite, leading to smaller overlap between the charge transfer donor and acceptor wavefunctions and smaller super-exchange coupling in chromia. Nevertheless, the weaker coupling in chromia is still sufficiently large to suggest that charge transport processes in chromia are adiabatic in nature. The electronic coupling is found to depend on both the superexchange interaction through the bridging oxygen atoms and the d-shell electron spin coupling within the Cr-Cr donor-acceptor pair, while the reorganization energy is essentially independent of the electron spin coupling.« less
Theoretical characterization of charge transport in chromia (α-Cr2O3)

NASA Astrophysics Data System (ADS)

Iordanova, N.; Dupuis, M.; Rosso, K. M.

2005-08-01

Transport of conduction electrons and holes through the lattice of α-Cr2O3 (chromia) is modeled as a valence alternation of chromium cations using ab initio electronic structure calculations and electron-transfer theory. In the context of the small polaron model, a cluster approach was used to compute quantities controlling the mobility of localized electrons and holes, i.e., the reorganization energy and the electronic coupling matrix element that enter Marcus' theory. The calculation of the electronic coupling followed the generalized Mulliken-Hush approach using the complete active space self-consistent-field (CASSCF) method and the quasidiabatic method. Our findings indicate that hole mobility is more than three orders of magnitude larger than electron mobility in both (001) and [001] lattice directions. The difference arises mainly from the larger internal reorganization energy calculated for electron-transport relative to hole-transport processes while electronic couplings have similar magnitudes. The much larger hole mobility versus electron mobility in α-Cr2O3 is in contrast to similar hole and electron mobilities in hematite α-Fe2O3 previously calculated. Our calculations also indicate that the electronic coupling for all charge-transfer processes of interest is smaller than for the corresponding processes in hematite. This variation is attributed to the weaker interaction between the metal 3d states and the O(2p ) states in chromia than in hematite, leading to a smaller overlap between the charge-transfer donor and acceptor wave functions and smaller superexchange coupling in chromia. Nevertheless, the weaker coupling in chromia is still sufficiently large to suggest that charge-transport processes in chromia are adiabatic in nature. The electronic coupling is found to depend on both the superexchange interaction through the bridging oxygen atoms and the d-shell electron-spin coupling within the Cr-Cr donor-acceptor pair, while the reorganization energy is essentially independent of the electron-spin coupling.
Enhancing mHealth Technology in the PCMH Environment to Activate Chronic Care Patients

DTIC Science & Technology

2017-09-01

AVAILABILITY STATEMENT Approved for Public Release; Distribution Unlimited 13. SUPPLEMENTARY NOTES - 14. ABSTRACT - The potential of mobile health (mHealth...biometric data, electronic coaching, electronic-based health education, secure e-mail communication between visits, and electronic collection of lifestyle...influence patient activation and self-care activities. 15. SUBJECT TERMS MHCE, Mobile Health Care Environment mHealth, mobile health MHS, Military Health
Non-thermal plasma instabilities induced by deformation of the electron energy distribution function

NASA Astrophysics Data System (ADS)

Dyatko, N. A.; Kochetov, I. V.; Napartovich, A. P.

2014-08-01

Non-thermal plasma is a key component in gas lasers, microelectronics, medical applications, waste gas cleaners, ozone generators, plasma igniters, flame holders, flow control in high-speed aerodynamics and others. A specific feature of non-thermal plasma is its high sensitivity to variations in governing parameters (gas composition, pressure, pulse duration, E/N parameter). This sensitivity is due to complex deformations of the electron energy distribution function (EEDF) shape induced by variations in electric field strength, electron and ion number densities and gas excitation degree. Particular attention in this article is paid to mechanisms of instabilities based on non-linearity of plasma properties for specific conditions: gas composition, steady-state and decaying plasma produced by the electron beam, or by an electric current pulse. The following effects are analyzed: the negative differential electron conductivity; the absolute negative electron mobility; the stepwise changes of plasma properties induced by the EEDF bi-stability; thermo-current instability and the constriction of the glow discharge column in rare gases. Some of these effects were observed experimentally and some of them were theoretically predicted and still wait for experimental confirmation.
Electron Mobility and Trapping in Ferrihydrite Nanoparticles

DOE Office of Scientific and Technical Information (OSTI.GOV)

Soltis, Jennifer A.; Schwartzberg, Adam M.; Zarzycki, Piotr

Iron is the most abundant transition metal in the Earth’s crust, and naturally occurring iron oxide minerals play a commanding role in environmental redox reactions. Although iron oxide redox reactions are well-studied, their precise mechanisms are not fully understood. Recent work has shown that these involve electron transfer pathways within the solid, suggesting that overall reaction rates could be dependent upon electron mobility. Initial ultrafast spectroscopy studies of iron oxide nanoparticles sensitized by fluorescein derivatives supported a model for electron mobility based on polaronic hopping of electron charge carriers between iron sites, but the constitutive relationships between hopping mobilities andmore » interfacial charge transfer processes has remained obscured. In this paper, we developed a coarse-grained lattice Monte Carlo model to simulate the collective mobilities and lifetimes of these photoinjected electrons with respect to recombination with adsorbed dye molecules for essential nanophase ferrihydrite and tested predictions made by the simulations using pump–probe spectroscopy. We acquired optical transient absorption spectra as a function of the particle size and under a variety of solution conditions and used cryogenic transmission electron microscopy to determine the aggregation state of the nanoparticles. We observed biphasic electron recombination kinetics over time scales that spanned from picoseconds to microseconds, the slower regime of which was fit with a stretched exponential decay function. The recombination rates were weakly affected by the nanoparticle size and aggregation state, suspension pH, and injection of multiple electrons per nanoparticle. Finally, we conclude that electron mobility indeed limits the rate of interfacial electron transfer in these systems, with the slowest processes relating to escape from deep traps, the presence of which outweighs the influence of environmental factors, such as pH-dependent surface charge.« less
Electron Mobility and Trapping in Ferrihydrite Nanoparticles

DOE PAGES

Soltis, Jennifer A.; Schwartzberg, Adam M.; Zarzycki, Piotr; ...

2017-05-18

Iron is the most abundant transition metal in the Earth’s crust, and naturally occurring iron oxide minerals play a commanding role in environmental redox reactions. Although iron oxide redox reactions are well-studied, their precise mechanisms are not fully understood. Recent work has shown that these involve electron transfer pathways within the solid, suggesting that overall reaction rates could be dependent upon electron mobility. Initial ultrafast spectroscopy studies of iron oxide nanoparticles sensitized by fluorescein derivatives supported a model for electron mobility based on polaronic hopping of electron charge carriers between iron sites, but the constitutive relationships between hopping mobilities andmore » interfacial charge transfer processes has remained obscured. In this paper, we developed a coarse-grained lattice Monte Carlo model to simulate the collective mobilities and lifetimes of these photoinjected electrons with respect to recombination with adsorbed dye molecules for essential nanophase ferrihydrite and tested predictions made by the simulations using pump–probe spectroscopy. We acquired optical transient absorption spectra as a function of the particle size and under a variety of solution conditions and used cryogenic transmission electron microscopy to determine the aggregation state of the nanoparticles. We observed biphasic electron recombination kinetics over time scales that spanned from picoseconds to microseconds, the slower regime of which was fit with a stretched exponential decay function. The recombination rates were weakly affected by the nanoparticle size and aggregation state, suspension pH, and injection of multiple electrons per nanoparticle. Finally, we conclude that electron mobility indeed limits the rate of interfacial electron transfer in these systems, with the slowest processes relating to escape from deep traps, the presence of which outweighs the influence of environmental factors, such as pH-dependent surface charge.« less
Field testing of two electronic mobility aid devices for persons who are deaf-blind.

PubMed

Vincent, Claude; Routhier, François; Martel, Valérie; Mottard, Marie-Ève; Dumont, Frédéric; Côté, Lise; Cloutier, Danielle

2014-09-01

To test a methodology for assessing the effects of electronic mobility aid devices (EMAD) on the mobility of persons who are deaf-blind in real-life situations. A single-subject desing was done with four users followed in a program for persons who are deaf-blind. Participants were trained to use two commercial EMADs: the Miniguide and the Breeze. The Canadian Measure of Occupational Performance (CMOP) was administered before training (T1), after training (T2) and three months later (T3). The Quebec User Evaluation of Satisfaction with assistive Technology (QUEST) was administered at T2 and T3. A follow-up interview was conducted with the participants and clinicians at T3 to evaluate the benefits of the EMAD and any problems. CMOP suggests that both performance and satisfaction improved following the use of both EMADs in four occupations (functional mobility, active leisure, community life and socialization). QUEST indicates high satisfaction with eight items except for one participant. Follow-up interviews revealed a wide variety of perceptions regarding EMAD use and seven problems although CMOP and QUEST indicated good satisfaction. A high satisfaction score on QUEST does not necessarily imply that an assistive device is efficient in all circumstances; follow-up interviews provided important complementary information. For people who are deaf-blind The Miniguide is reliable for detecting obstacles (vibrations are sent as a warning when approaching an obstacle). It is often used to know if taking the right route. It identifies entrances or openings (indicated by the vibrations stopping when pointing at a wall), which can replace the echo-location for blind persons with hearing impairments. The Miniguide helped to locate overhanging objects which are not detectable with a long cane. The Breeze can record landmarks for orientation and it possible to use those landmarks to go back alone later after taking a certain route for the first time with someone else. It helps to familiarize the person with new places. It can tell you where you are at any time. It helps with orientation and the participant also liked this feature because it helped with learning street names. The Miniguide and the Breeze were not efficient in all circumstances; there were some problems with the ergonomic (both), detecting snow banks (Miniguide), sensitiveness to the surroundings in crowded places (Miniguide) and exactitude for geo-localization (Breeze).
Design reflowable digital book template

NASA Astrophysics Data System (ADS)

Prasetya, Didik Dwi; Widiyaningtyas, Triyanna; Arifin, M. Zainal; Wahyu Sakti G., I.

2017-09-01

Electronic books (e-books or digital books) increasingly in demand and continue to grow in the form of future books. One of the standard format electronic books that potential is EPUB (electronic publication) published by the International Digital Publishing Forum (IDPF). This digital book has major advantages are able to provide interactive and reflowable content, which are not found in another book format, such as PDF. Reflowable content allows the book can be accessed through a variety of reader device, like desktop and mobile with a fit and comfort view. However, because the generating process of an EPUB digital book is not as easy a PDF, so this format is less popular. Therefore, in order to help overcome the existing problems, this paper develops digital reflowable text book templates to support electronic learning, especially in Indonesia. This template can be used by anyone to produce a standard digital book quickly and easily without requiring additional specialized knowledge.
Mechanical flip-chip for ultra-high electron mobility devices

DOE PAGES

Bennaceur, Keyan; Schmidt, Benjamin A.; Gaucher, Samuel; ...

2015-09-22

In this study, electrostatic gates are of paramount importance for the physics of devices based on high-mobility two-dimensional electron gas (2DEG) since they allow depletion of electrons in selected areas. This field-effect gating enables the fabrication of a wide range of devices such as, for example, quantum point contacts (QPC), electron interferometers and quantum dots. To fabricate these gates, processing is usually performed on the 2DEG material, which is in many cases detrimental to its electron mobility. Here we propose an alternative process which does not require any processing of the 2DEG material other than for the ohmic contacts. Thismore » approach relies on processing a separate wafer that is then mechanically mounted on the 2DEG material in a flip-chip fashion. This technique proved successful to fabricate quantum point contacts on both GaAs/AlGaAs materials with both moderate and ultra-high electron mobility.« less
GaN-on-silicon high-electron-mobility transistor technology with ultra-low leakage up to 3000 V using local substrate removal and AlN ultra-wide bandgap

NASA Astrophysics Data System (ADS)

Dogmus, Ezgi; Zegaoui, Malek; Medjdoub, Farid

2018-03-01

We report on extremely low off-state leakage current in AlGaN/GaN-on-silicon metal–insulator–semiconductor high-electron-mobility transistors (MISHEMTs) up to a high blocking voltage. Remarkably low off-state gate and drain leakage currents below 1 µA/mm up to 3 kV have been achieved owing to the use of a thick in situ SiN gate dielectric under the gate, and a local Si substrate removal technique combined with a cost effective 15-µm-thick AlN dielectric layer followed by a Cu deposition. This result establishes a manufacturable state-of-the-art high-voltage GaN-on-silicon power transistors while maintaining a low specific on-resistance of approximately 10 mΩ·cm2.
Properties of Ir-based Ohmic contacts to AlGaN/GaN high electron mobility transistors

NASA Astrophysics Data System (ADS)

Fitch, R. C.; Gillespie, J. K.; Moser, N.; Jenkins, T.; Sewell, J.; Via, D.; Crespo, A.; Dabiran, A. M.; Chow, P. P.; Osinsky, A.; La Roche, J. R.; Ren, F.; Pearton, S. J.

2004-03-01

Measurement of the electrical characteristics of 250 devices on the same 2 in. diameter wafer shows that Ti/Al/Ir/Au Ohmic contacts on AlGaN/GaN high electron mobility transistors (HEMTs) have lower average specific contact resistance after annealing at 850 °C for 30 s (4.6×10-5 Ω cm2) compared to more standard Ti/Al/Ni/Au contacts (2×10-4 Ω cm2). HEMTs with these Ir-based contacts also show average interdevice isolation currents approximately a factor of 2 lower, higher peak transconductance (134 mS/mm compared to 121 mS/mm), and higher device breakdown voltage (31 V compared to 23 V) than the devices with Ni-based contacts. This Ir-based contact metallurgy looks promising for applications requiring extended thermal stability of the HEMTs.

Gamification and Multimedia for Medical Education: A Landscape Review.

PubMed

McCoy, Lise; Lewis, Joy H; Dalton, David

2016-01-01

Medical education is rapidly evolving. Students enter medical school with a high level of technological literacy and an expectation for instructional variety in the curriculum. In response, many medical schools now incorporate technology-enhanced active learning and multimedia education applications. Education games, medical mobile applications, and virtual patient simulations are together termed gamified training platforms. To review available literature for the benefits of using gamified training platforms for medical education (both preclinical and clinical) and training. Also, to identify platforms suitable for these purposes with links to multimedia content. Peer-reviewed literature, commercially published media, and grey literature were searched to compile an archive of recently published scientific evaluations of gamified training platforms for medical education. Specific educational games, mobile applications, and virtual simulations useful for preclinical and clinical training were identified and categorized. Available evidence was summarized as it related to potential educational advantages of the identified platforms for medical education. Overall, improved learning outcomes have been demonstrated with virtual patient simulations. Games have the potential to promote learning, increase engagement, allow for real-word application, and enhance collaboration. They can also provide opportunities for risk-free clinical decision making, distance training, learning analytics, and swift feedback. A total of 5 electronic games and 4 mobile applications were identified for preclinical training, and 5 electronic games, 10 mobile applications, and 12 virtual patient simulation tools were identified for clinical training. Nine additional gamified, virtual environment training tools not commercially available were also identified. Many published studies suggest possible benefits from using gamified media in medical curriculum. This is a rapidly growing field. More research is required to rigorously evaluate the specific educational benefits of these interventions. This archive of hyperlinked tools can be used as a resource for all levels of medical trainees, providers, and educators.
Carrier mobility in double-helix DNA and RNA: A quantum chemistry study with Marcus-Hush theory.

PubMed

Wu, Tao; Sun, Lei; Shi, Qi; Deng, Kaiming; Deng, Weiqiao; Lu, Ruifeng

2016-12-21

Charge mobilities of six DNAs and RNAs have been computed using quantum chemistry calculation combined with the Marcus-Hush theory. Based on this simulation model, we obtained quite reasonable results when compared with the experiment, and the obtained charge mobility strongly depends on the molecular reorganization and electronic coupling. Besides, we find that hole mobilities are larger than electron mobilities no matter in DNAs or in RNAs, and the hole mobility of 2L8I can reach 1.09 × 10 -1 cm 2 V -1 s -1 which can be applied in the molecular wire. The findings also show that our theoretical model can be regarded as a promising candidate for screening DNA- and RNA-based molecular electronic devices.
Carrier mobility in double-helix DNA and RNA: A quantum chemistry study with Marcus-Hush theory

NASA Astrophysics Data System (ADS)

Wu, Tao; Sun, Lei; Shi, Qi; Deng, Kaiming; Deng, Weiqiao; Lu, Ruifeng

2016-12-01

Charge mobilities of six DNAs and RNAs have been computed using quantum chemistry calculation combined with the Marcus-Hush theory. Based on this simulation model, we obtained quite reasonable results when compared with the experiment, and the obtained charge mobility strongly depends on the molecular reorganization and electronic coupling. Besides, we find that hole mobilities are larger than electron mobilities no matter in DNAs or in RNAs, and the hole mobility of 2L8I can reach 1.09 × 10-1 cm2 V-1 s-1 which can be applied in the molecular wire. The findings also show that our theoretical model can be regarded as a promising candidate for screening DNA- and RNA-based molecular electronic devices.
Polaron mobility obtained by a variational approach for lattice Fröhlich models

NASA Astrophysics Data System (ADS)

Kornjača, Milan; Vukmirović, Nenad

2018-04-01

Charge carrier mobility for a class of lattice models with long-range electron-phonon interaction was investigated. The approach for mobility calculation is based on a suitably chosen unitary transformation of the model Hamiltonian which transforms it into the form where the remaining interaction part can be treated as a perturbation. Relevant spectral functions were then obtained using Matsubara Green's functions technique and charge carrier mobility was evaluated using Kubo's linear response formula. Numerical results were presented for a wide range of electron-phonon interaction strengths and temperatures in the case of one-dimensional version of the model. The results indicate that the mobility decreases with increasing temperature for all electron-phonon interaction strengths in the investigated range, while longer interaction range leads to more mobile carriers.
Fundamental limits on the electron mobility of β-Ga2O3

NASA Astrophysics Data System (ADS)

Kang, Youngho; Krishnaswamy, Karthik; Peelaers, Hartwin; Van de Walle, Chris G.

2017-06-01

We perform first-principles calculations to investigate the electronic and vibrational spectra and the electron mobility of β-Ga2O3. We calculate the electron-phonon scattering rate of the polar optical phonon modes using the Vogl model in conjunction with Fermi’s golden rule; this enables us to fully take the anisotropic phonon spectra of the monoclinic lattice of β-Ga2O3 into account. We also examine the scattering rate due to ionized impurities or defects using a Yukawa-potential-based model. We consider scattering due to donor impurities, as well as the possibility of compensation by acceptors such as Ga vacancies. We then calculate the room-temperature mobility of β-Ga2O3 using the Boltzmann transport equation within the relaxation time approximation, for carrier densities in the range from 1017 to 1020 cm-3. We find that the electron-phonon interaction dominates the mobility for carrier densities of up to 1019 cm-3. We also find that the intrinsic anisotropy in the mobility is small; experimental findings of large anisotropy must therefore be attributed to other factors. We attribute the experimentally observed reduction of the mobility with increasing carrier density to increasing levels of compensation, which significantly affect the mobility.
Fundamental limits on the electron mobility of β-Ga2O3.

PubMed

Kang, Youngho; Krishnaswamy, Karthik; Peelaers, Hartwin; Van de Walle, Chris G

2017-06-14

We perform first-principles calculations to investigate the electronic and vibrational spectra and the electron mobility of β-Ga 2 O 3 . We calculate the electron-phonon scattering rate of the polar optical phonon modes using the Vogl model in conjunction with Fermi's golden rule; this enables us to fully take the anisotropic phonon spectra of the monoclinic lattice of β-Ga 2 O 3 into account. We also examine the scattering rate due to ionized impurities or defects using a Yukawa-potential-based model. We consider scattering due to donor impurities, as well as the possibility of compensation by acceptors such as Ga vacancies. We then calculate the room-temperature mobility of β-Ga 2 O 3 using the Boltzmann transport equation within the relaxation time approximation, for carrier densities in the range from 10 17 to 10 20 cm -3 . We find that the electron-phonon interaction dominates the mobility for carrier densities of up to 10 19 cm -3 . We also find that the intrinsic anisotropy in the mobility is small; experimental findings of large anisotropy must therefore be attributed to other factors. We attribute the experimentally observed reduction of the mobility with increasing carrier density to increasing levels of compensation, which significantly affect the mobility.
Modeling charge transport in organic photovoltaic materials.

PubMed

Nelson, Jenny; Kwiatkowski, Joe J; Kirkpatrick, James; Frost, Jarvist M

2009-11-17

The performance of an organic photovoltaic cell depends critically on the mobility of charge carriers within the constituent molecular semiconductor materials. However, a complex combination of phenomena that span a range of length and time scales control charge transport in disordered organic semiconductors. As a result, it is difficult to rationalize charge transport properties in terms of material parameters. Until now, efforts to improve charge mobilities in molecular semiconductors have proceeded largely by trial and error rather than through systematic design. However, recent developments have enabled the first predictive simulation studies of charge transport in disordered organic semiconductors. This Account describes a set of computational methods, specifically molecular modeling methods, to simulate molecular packing, quantum chemical calculations of charge transfer rates, and Monte Carlo simulations of charge transport. Using case studies, we show how this combination of methods can reproduce experimental mobilities with few or no fitting parameters. Although currently applied to material systems of high symmetry or well-defined structure, further developments of this approach could address more complex systems such anisotropic or multicomponent solids and conjugated polymers. Even with an approximate treatment of packing disorder, these computational methods simulate experimental mobilities within an order of magnitude at high electric fields. We can both reproduce the relative values of electron and hole mobility in a conjugated small molecule and rationalize those values based on the symmetry of frontier orbitals. Using fully atomistic molecular dynamics simulations of molecular packing, we can quantitatively replicate vertical charge transport along stacks of discotic liquid crystals which vary only in the structure of their side chains. We can reproduce the trends in mobility with molecular weight for self-organizing polymers using a cheap, coarse-grained structural simulation method. Finally, we quantitatively reproduce the field-effect mobility in disordered C60 films. On the basis of these results, we conclude that all of the necessary building blocks are in place for the predictive simulation of charge transport in macromolecular electronic materials and that such methods can be used as a tool toward the future rational design of functional organic electronic materials.
Diverse carrier mobility of monolayer BNC_x: A combined density functional theory and Boltzmann transport theory study.

PubMed

Wu, Tao; Deng, Kaiming; Deng, Wei-Qiao; Lu, Ruifeng

2017-09-19

BNCX monolayer as a kind of two-dimensional material has numerous chemical atomic ratios and arrangements with different electronic structures. Via calculations on the basis of density functional theory and Boltzmann transport theory under deformation potential approximation, the band structures and carrier mobilities of BNCX (x=1,2,3,4) nanosheets are systematically investigated. The calculated results show that BNC2-1 is a material with very small band gap (0.02 eV) among all the structures while other BNCX monolayers are semiconductors with band gap ranging from 0.51 to 1.32 eV. The carrier mobility of BNCX varies considerably from tens to millions of cm2 V-1 s-1. For BNC2-1, the hole mobility and electron mobility along both x and y directions can reach 105 orders of magnitude, which is similar to the carrier mobility of graphene. Besides, all studied BNCX monolayers obviously have anisotropic hole mobility and electron mobility. In particular, for semiconductor BNC4, its hole mobility along y direction and electron mobility along x direction unexpectedly reach 106 orders of magnitude, even higher than that of graphene. Our findings suggest that BNCX layered materials with proper ratio and arrangement of carbon atoms will possess desirable charge transport properties, exhibiting potential applications in nanoelectronic devices. © 2017 IOP Publishing Ltd.
Effect of electromagnetic radiations from mobile phone base stations on general health and salivary function.

PubMed

Singh, Kushpal; Nagaraj, Anup; Yousuf, Asif; Ganta, Shravani; Pareek, Sonia; Vishnani, Preeti

2016-01-01

Cell phones use electromagnetic, nonionizing radiations in the microwave range, which some believe may be harmful to human health. The present study aimed to determine the effect of electromagnetic radiations (EMRs) on unstimulated/stimulated salivary flow rate and other health-related problems between the general populations residing in proximity to and far away from mobile phone base stations. A total of four mobile base stations were randomly selected from four zones of Jaipur, Rajasthan, India. Twenty individuals who were residing in proximity to the selected mobile phone towers were taken as the case group and the other 20 individuals (control group) who were living nearly 1 km away in the periphery were selected for salivary analysis. Questions related to sleep disturbances were measured using Pittsburgh Sleep Quality Index (PSQI) and other health problems were included in the questionnaire. Chi-square test was used for statistical analysis. It was unveiled that a majority of the subjects who were residing near the mobile base station complained of sleep disturbances, headache, dizziness, irritability, concentration difficulties, and hypertension. A majority of the study subjects had significantly lesser stimulated salivary secretion (P < 0.01) as compared to the control subjects. The effects of prolonged exposure to EMRs from mobile phone base stations on the health and well-being of the general population cannot be ruled out. Further studies are warranted to evaluate the effect of electromagnetic fields (EMFs) on general health and more specifically on oral health.
Extensive domain motion and electron transfer in the human electron transferring flavoprotein.medium chain Acyl-CoA dehydrogenase complex.

PubMed

Toogood, Helen S; van Thiel, Adam; Basran, Jaswir; Sutcliffe, Mike J; Scrutton, Nigel S; Leys, David

2004-07-30

The crystal structure of the human electron transferring flavoprotein (ETF).medium chain acyl-CoA dehydrogenase (MCAD) complex reveals a dual mode of protein-protein interaction, imparting both specificity and promiscuity in the interaction of ETF with a range of structurally distinct primary dehydrogenases. ETF partitions the functions of partner binding and electron transfer between (i) the recognition loop, which acts as a static anchor at the ETF.MCAD interface, and (ii) the highly mobile redox active FAD domain. Together, these enable the FAD domain of ETF to sample a range of conformations, some compatible with fast interprotein electron transfer. Disorders in amino acid or fatty acid catabolism can be attributed to mutations at the protein-protein interface. Crucially, complex formation triggers mobility of the FAD domain, an induced disorder that contrasts with general models of protein-protein interaction by induced fit mechanisms. The subsequent interfacial motion in the MCAD.ETF complex is the basis for the interaction of ETF with structurally diverse protein partners. Solution studies using ETF and MCAD with mutations at the protein-protein interface support this dynamic model and indicate ionic interactions between MCAD Glu(212) and ETF Arg alpha(249) are likely to transiently stabilize productive conformations of the FAD domain leading to enhanced electron transfer rates between both partners.
Present status of recycling waste mobile phones in China: a review.

PubMed

Li, Jingying; Ge, Zhongying; Liang, Changjin; An, Ni

2017-07-01

A large number of waste mobile phones have already been generated and are being generated. Various countries around the world have all been positively exploring the way of recycling and reuse when facing such a large amount of waste mobile phones. In some countries, processing waste mobile phones has been forming a complete industrial chain, which can not only recycle waste mobile phones to reduce their negative influence on the environment but also turn waste into treasure to acquire economic benefits dramatically. However, the situation of recycling waste mobile phones in China is not going well. Waste mobile phones are not formally covered by existing regulations and policies for the waste electric and electronic equipment in China. In order to explore an appropriate system to recover waste mobile phones, the mobile phone production and the amount of waste mobile phones are introduced in this paper, and status of waste mobile phones recycling is described; then, the disposal technology of electronic waste that would be most likely to be used for processing of electronic waste in industrial applications in the near future is reviewed. Finally, rationalization proposals are put forward based on the current recovery status of waste mobile phones for the purpose of promoting the development of recycling waste mobile phones in developing countries with a special emphasis on China.
Enhanced electron mobility at the two-dimensional metallic surface of BaSnO3 electric-double-layer transistor at low temperatures

NASA Astrophysics Data System (ADS)

Fujiwara, Kohei; Nishihara, Kazuki; Shiogai, Junichi; Tsukazaki, Atsushi

2017-05-01

Wide-bandgap oxides exhibiting high electron mobility hold promise for the development of useful electronic and optoelectronic devices as well as for basic research on two-dimensional electron transport phenomena. A perovskite-type tin oxide, BaSnO3, is currently one of such targets owing to distinctly high mobility at room temperature. The challenge to overcome towards the use of BaSnO3 thin films in applications is suppression of dislocation scattering, which is one of the dominant scattering origins for electron transport. Here, we show that the mobility of the BaSnO3 electric-double-layer transistor reaches 300 cm2 V-1 s-1 at 50 K. The improved mobility indicates that charged dislocation scattering is effectively screened by electrostatically doped high-density charge carriers. We also observed metallic conduction persisting down to 2 K, which is attributed to the transition to the degenerate semiconductor. The experimental verification of bulk-level mobility at the densely accumulated surface sheds more light on the importance of suppression of dislocation scattering by interface engineering in doped BaSnO3 thin films for transparent electrode applications.
Linking guidelines to Electronic Health Record design for improved chronic disease management.

PubMed

Barretto, Sistine A; Warren, Jim; Goodchild, Andrew; Bird, Linda; Heard, Sam; Stumptner, Markus

2003-01-01

The promise of electronic decision support to promote evidence based practice remains elusive in the context of chronic disease management. We examine the problem of achieving a close relationship of Electronic Health Record (EHR) content to other components of a clinical information system (guidelines, decision support and workflow), particularly linking the decisions made by providers back to the guidelines. We use the openEHR architecture, which allows extension of a core Reference Model via Archetypes to refine the detailed information recording options for specific classes of encounter. We illustrate the use of openEHR for tracking the relationship of a series of clinical encounters to a guideline via a case study of guideline-compliant treatment of hypertension in diabetes. This case study shows the contribution guideline content can have on problem-specific EHR structure and demonstrates the potential for a constructive interaction of electronic decision support and the EHR.
Linking Guidelines to Electronic Health Record Design for Improved Chronic Disease Management

PubMed Central

Barretto, Sistine A.; Warren, Jim; Goodchild, Andrew; Bird, Linda; Heard, Sam; Stumptner, Markus

2003-01-01

The promise of electronic decision support to promote evidence based practice remains elusive in the context of chronic disease management. We examine the problem of achieving a close relationship of Electronic Health Record (EHR) content to other components of a clinical information system (guidelines, decision support and work-flow), particularly linking the decisions made by providers back to the guidelines. We use the openEHR architecture, which allows extension of a core Reference Model via Archetypes to refine the detailed information recording options for specific classes of encounter. We illustrate the use of openEHR for tracking the relationship of a series of clinical encounters to a guideline via a case study of guideline-compliant treatment of hypertension in diabetes. This case study shows the contribution guideline content can have on problem-specific EHR structure and demonstrates the potential for a constructive interaction of electronic decision support and the EHR. PMID:14728135
Ambulatory EHR functionality: a comparison of functionality lists.

PubMed

Drury, Barbara M

2006-01-01

There is a proliferation of lists intended to define and clarify the functionality of an ambulatory electronic health record system. These lists come from both private and public entities and vary in terminology, granularity, usability, and comprehensiveness. For example, functionality regarding a problem list includes the following possible definitions: * "Create and maintain patient-specific problem lists," from the HL7 Electronic Health Record Draft Standard for Trial Use. * "Provide a flexible mechanism for retrieval of encounter information that can be organized by diagnosis, problem, problem type," from the Bureau of Primary Health Care. * "The system shall associate encounters, orders, medications and notes with one or more problems," from the Certification Commission on Health Information Technology. * "Displays dates of problems on problem list," from COPIC Insurance Co. * "Shall automatically close acute problems using an automated algorithm," from the Physicians Foundations HIT Subcommittee. This article will compare the attributes of these five electronic health record functionality lists and their usefulness to different audiences-clinicians, application developers and payers.
Effects of macroscopic inhomogeneities on electron mobility in semi-insulating GaAs

NASA Technical Reports Server (NTRS)

Walukiewicz, W.; Wang, L.; Pawlowicz, L. M.; Lagowski, J.; Gatos, H. C.

1986-01-01

It is shown that defect inhomogeneities of sizes larger than the electron mean free path are responsible for the low values and anomalous temperature dependence of the electron mobility in semi-insulating (SI) GaAs. The room-temperature electron mobility values below about 6000 sq cm/V s cannot be uniquely used for the determination of the concentration of ionized defects, since the contribution from inhomogeneities usually exceeds that from scattering by ionized impurities. The effects of the macroscopically inhomogeneous distribution of residual acceptors and the major deep donor EL2 diminish at elevated temperatures between 600 and 900 K, which offers a means for identification of inhomogeneities, and furthermore explains recently reported steplike mobility versus temperature behavior in SI-GaAs.
Charge transport in metal oxides: A theoretical study of hematite α-Fe2O3

NASA Astrophysics Data System (ADS)

Iordanova, N.; Dupuis, M.; Rosso, K. M.

2005-04-01

Transport of conduction electrons and holes through the lattice of α-Fe2O3 (hematite) is modeled as a valence alternation of iron cations using ab initio electronic structure calculations and electron transfer theory. Experimental studies have shown that the conductivity along the (001) basal plane is four orders of magnitude larger than the conductivity along the [001] direction. In the context of the small polaron model, a cluster approach was used to compute quantities controlling the mobility of localized electrons and holes, i.e., the reorganization energy and the electronic coupling matrix element that enter Marcus' theory. The calculation of the electronic coupling followed the generalized Mulliken-Hush approach using the complete active space self-consistent field method. Our findings demonstrate an approximately three orders of magnitude anisotropy in both electron and hole mobility between directions perpendicular and parallel to the c axis, in good accord with experimental data. The anisotropy arises from the slowness of both electron and hole mobilities across basal oxygen planes relative to that within iron bilayers between basal oxygen planes. Interestingly, for elementary reaction steps along either of the directions considered, there is only less than one order of magnitude difference in mobility between electrons and holes, in contrast to accepted classical arguments. Our findings indicate that the most important quantity underlying mobility differences is the electronic coupling, albeit the reorganization energy contributes as well. The large values computed for the electronic coupling suggest that charge transport reactions in hematite are adiabatic in nature. The electronic coupling is found to depend on both the superexchange interaction through the bridging oxygen atoms and the d-shell electron spin coupling within the Fe-Fe donor-acceptor pair, while the reorganization energy is essentially independent of the electron spin coupling.
Moving Finite Elements in 2-D.

DTIC Science & Technology

1982-06-07

that a small number of control parameters would allow a great deal of flexibility in the type of node mobility available in specific problems while...CLEO 󈨕), Washington, DC, June 10-12, 1981.) 5. R. J. Gelinas and S. K. Doss, "The Moving Finite Element Method: 1-D Transient Flow Aplications ," to
Breaking the barriers of all-polymer solar cells: Solving electron transporter and morphology problems

NASA Astrophysics Data System (ADS)

Gavvalapalli, Nagarjuna

All-polymer solar cells (APSC) are a class of organic solar cells in which hole and electron transporting phases are made of conjugated polymers. Unlike polymer/fullerene solar cell, photoactive material of APSC can be designed to have hole and electron transporting polymers with complementary absorption range and proper frontier energy level offset. However, the highest reported PCE of APSC is 5 times less than that of polymer/fullerene solar cell. The low PCE of APSC is mainly due to: i) low charge separation efficiency; and ii) lack of optimal morphology to facilitate charge transfer and transport; and iii) lack of control over the exciton and charge transport in each phase. My research work is focused towards addressing these issues. The charge separation efficiency of APSC can be enhanced by designing novel electron transporting polymers with: i) broad absorption range; ii) high electron mobility; and iii) high dielectric constant. In addition to with the above parameters chemical and electronic structure of the repeating unit of conjugated polymer also plays a role in charge separation efficiency. So far only three classes of electron transporting polymers, CN substituted PPV, 2,1,3-benzothiadiazole derived polymers and rylene diimide derived polymers, are used in APSC. Thus to enhance the charge separation efficiency new classes of electron transporting polymers with the above characteristics need to be synthesized. I have developed a new straightforward synthetic strategy to rapidly generate new classes of electron transporting polymers with different chemical and electronic structure, broad absorption range, and high electron mobility from readily available electron deficient monomers. In APSCs due to low entropy of mixing, polymers tend to micro-phase segregate rather than forming the more useful nano-phase segregation. Optimizing the polymer blend morphology to obtain nano-phase segregation is specific to the system under study, time consuming, and not trivial. Thus to avoid micro-phase segregation, nanoparticles of hole and electron transporters are synthesized and blended. But the PCE of nanoparticle blends are far less than those of polymer blends. This is mainly due to the: i) lack of optimal assembly of nanoparticles to facilitate charge transfer and transport processes; and ii) lack of control over the exciton and charge transport properties within the nanoparticles. Polymer packing within the nanoparticle controls the optoelectronic and charge transport properties of the nanoparticle. In this work I have shown that the solvent used to synthesize nanoparticles plays a crucial role in determining the assembly of polymer chains inside the nanoparticle there by affecting its exciton and charge transport processes. To obtain the optimal morphology for better charge transfer and transport, we have also synthesized nanoparticles of different radius with surfactants of opposite charge. We propose that depending on the radius and/or Coulombic interactions these nanoparticles can be assembled into mineral structure-types that are useful for photovoltaic devices.
Optical properties of different graphene concentration in P3HT

NASA Astrophysics Data System (ADS)

Shariff, N. S. M.; Sarah, M. S. P.; Rusop, M.

2018-05-01

The discovery of Graphene has led to many new findings in material research. P3HT is a polymer that is well used in photovoltaic studies but the main problem is its low photocurrent due to its low electron mobility. Therefore the objective of this research is to increase the mobility in order to achieve higher photocurrent. In this research, P3HT will be mixed with Graphene and used as an active layer. The fabrication method used in this research is spin coating technique. Optical properties such as absorbance, transmittance and photoluminescence is characterized. Each optical properties shows a positive results when compared to P3HT layer. A concentration of 2 wt % shows the optimum absorbance and transmittance while quenching effect can be seen when compared to P3HT layer.

Mobile Technology Affinity in Renal Transplant Recipients.

PubMed

Reber, S; Scheel, J; Stoessel, L; Schieber, K; Jank, S; Lüker, C; Vitinius, F; Grundmann, F; Eckardt, K-U; Prokosch, H-U; Erim, Y

Medication nonadherence is a common problem in renal transplant recipients (RTRs). Mobile health approaches to improve medication adherence are a current trend, and several medication adherence apps are available. However, it is unknown whether RTRs use these technologies and to what extent. In the present study, the mobile technology affinity of RTRs was analyzed. We hypothesized significant age differences in mobile technology affinity and that mobile technology affinity is associated with better cognitive functioning as well as higher educational level. A total of 109 RTRs (63% male) participated in the cross-sectional study, with an overall mean age of 51.8 ± 14.2 years. The study included the Technology Experience Questionnaire (TEQ) for the assessment of mobile technology affinity, a cognitive test battery, and sociodemographic data. Overall, 57.4% of the patients used a smartphone or tablet and almost 45% used apps. The TEQ sum score was 20.9 in a possible range from 6 (no affinity to technology) to 30 (very high affinity). Younger patients had significantly higher scores in mobile technology affinity. The only significant gender difference was found in having fun with using electronic devices: Men enjoyed technology more than women did. Mobile technology affinity was positively associated with cognitive functioning and educational level. Young adult patients might profit most from mobile health approaches. Furthermore, high educational level and normal cognitive functioning promote mobile technology affinity. This should be kept in mind when designing mobile technology health (mHealth) interventions for RTRs. For beneficial mHealth interventions, further research on potential barriers and desired technologic features is necessary to adapt apps to patients' needs. Copyright © 2017 Elsevier Inc. All rights reserved.
On the Suitability of Mobile Cloud Computing at the Tactical Edge

DTIC Science & Technology

2014-04-23

geolocation; Facial recognition (photo identification/classification); Intelligence, Surveillance, and Reconnaissance (ISR); and Fusion of Electronic...could benefit most from MCC are those with large processing overhead, low bandwidth requirements, and a need for large database support (e.g., facial ... recognition , language translation). The effect—specifically on the communication links—of supporting these applications at the tactical edge
Mobile code security

NASA Astrophysics Data System (ADS)

Ramalingam, Srikumar

2001-11-01

A highly secure mobile agent system is very important for a mobile computing environment. The security issues in mobile agent system comprise protecting mobile hosts from malicious agents, protecting agents from other malicious agents, protecting hosts from other malicious hosts and protecting agents from malicious hosts. Using traditional security mechanisms the first three security problems can be solved. Apart from using trusted hardware, very few approaches exist to protect mobile code from malicious hosts. Some of the approaches to solve this problem are the use of trusted computing, computing with encrypted function, steganography, cryptographic traces, Seal Calculas, etc. This paper focuses on the simulation of some of these existing techniques in the designed mobile language. Some new approaches to solve malicious network problem and agent tampering problem are developed using public key encryption system and steganographic concepts. The approaches are based on encrypting and hiding the partial solutions of the mobile agents. The partial results are stored and the address of the storage is destroyed as the agent moves from one host to another host. This allows only the originator to make use of the partial results. Through these approaches some of the existing problems are solved.
Comparison between two portable devices for widefield PpIX fluorescence during cervical intraepithelial neoplasia treatment

NASA Astrophysics Data System (ADS)

Carbinatto, Fernanda M.; Inada, Natalia Mayumi; Lombardi, Welington; Cossetin, Natália Fernandez; Varoto, Cinthia; Kurachi, Cristina; Bagnato, Vanderlei Salvador

2015-06-01

The use of portable electronic devices, in particular mobile phones such as smartphones is increasing not only for all known applications, but also for diagnosis of diseases and monitoring treatments like topical Photodynamic Therapy. The aim of the study is to evaluate the production of the photosensitizer Protoporphyrin IX (PpIX) after topical application of a cream containing methyl aminolevulinate (MAL) in the cervix with diagnosis of Cervical Intraepithelial Neoplasia (CIN) through the fluorescence images captured after one and three hours and compare the images using two devices (a Sony Xperia® mobile and an Apple Ipod®. Was observed an increasing fluorescence intensity of the cervix three hours after cream application, in both portable electronic devices. However, because was used a specific program for the treatment of images using the Ipod® device, these images presented better resolution than observed by the Sony cell phone without a specific program. One hour after cream application presented a more selective fluorescence than the group of three hours. In conclusion, the use of portable devices to obtain images of PpIX fluorescence shown to be an effective tool and is necessary the improvement of programs for achievement of better results.
Improvement of electron mobility in La:BaSnO{sub 3} thin films by insertion of an atomically flat insulating (Sr,Ba)SnO{sub 3} buffer layer

DOE Office of Scientific and Technical Information (OSTI.GOV)

Shiogai, Junichi, E-mail: junichi.shiogai@imr.tohoku.ac.jp; Nishihara, Kazuki; Sato, Kazuhisa

One perovskite oxide, ASnO{sub 3} (A = Sr, Ba), is a candidate for use as a transparent conductive oxide with high electron mobility in single crystalline form. However, the electron mobility of films grown on SrTiO{sub 3} substrates does not reach the bulk value, probably because of dislocation scattering that originates from the large lattice mismatch. This study investigates the effect of insertion of bilayer BaSnO{sub 3} / (Sr,Ba)SnO{sub 3} for buffering this large lattice mismatch between La:BaSnO{sub 3} and SrTiO{sub 3} substrate. The insertion of 200-nm-thick BaSnO{sub 3} on (Sr,Ba)SnO{sub 3} bilayer buffer structures reduces the number of dislocationsmore » and improves surface smoothness of the films after annealing as proved respectively by scanning transmission electron microscopy and atomic force microscopy. A systematic investigation of BaSnO{sub 3} buffer layer thickness dependence on Hall mobility of the electron transport in La:BaSnO{sub 3} shows that the highest obtained value of mobility is 78 cm{sup 2}V{sup −1}s{sup −1} because of its fewer dislocations. High electron mobility films based on perovskite BaSnO{sub 3} can provide a good platform for transparent-conducting-oxide electronic devices and for creation of fascinating perovskite heterostructures.« less
Measurement of acetates in air using differential ion mobility spectrometer

NASA Astrophysics Data System (ADS)

Szczurek, Andrzej; Maciejewska, Monika; Zajiczek, Żaneta; Maziejuk, Mirosław

2017-11-01

Volatile organic compounds are one of the most important group of air pollutants. Potential health and environmental problems resulting from their emission prompted the requirement for monitoring these species. It motivates development of new measurement techniques which are fast, cost effective, reliable and field deployable. One of novel approaches is ion mobility spectrometry. It dwells on ion separation in electric field, based on differences in ion mobility. Many variants of this method are developed. In this wok, differential ion mobility spectrometry (DMS) was considered in respect of acetate measurements in air. It was demonstrated that DMS offers linear response to methyl, ethyl, propyl and butyl acetate in concentration range from 0.3 ppm to 7 ppm. Positive ions spectrum has to be utilised for this purpose. We showed that fragments of DMS spectrum which secure linearity are compound-specific. The obtained results are promising from the application point of view.
Electron and proton transfer in chloroplasts in silico. 2: The effect of diffusion limitations on the process of photosynthesis in spatially inhomogeneous thylakoids

NASA Astrophysics Data System (ADS)

Vershubskii, A. V.; Tikhonov, A. N.

2017-07-01

The lateral mobility of protons and mobile electron carriers (plastoquinone and plastocyanin) is subjected to diffusion limitations; the effect of these limitations on the kinetics of photoinduced pH i changes has been investigated in the present work for metabolic states 3 (conditions of intensive ATP synthesis) and 4 (the state of photosynthetic control). Computer simulations were based on a mathematical model of electron and proton transport in chloroplasts developed earlier by the authors. Non-uniform distribution of electron carriers and ATP synthase complexes in the membranes of grana and intergranal thylakoids was taken into account in the model. The kinetics of intrathylakoid pH i changes and the lateral profiles of distribution of the mobile electron transporters in granal and intergranal thylakoids were studied. The formation of non-uniform pH i profiles (with lumen acidification in the central parts of the grana being substantially slower than in the stromal thylakoids) was shown to occur under the conditions of ATP synthesis. Variation of the diffusion coefficients of intrathylakoid hydrogen ions and mobile electron carriers (plastoquinone and plastocyanin) can have substantial effects on the lateral pH i profiles and the redox state of the mobile electron carriers.
Design rules for charge-transport efficient host materials for phosphorescent organic light-emitting diodes.

PubMed

May, Falk; Al-Helwi, Mustapha; Baumeier, Björn; Kowalsky, Wolfgang; Fuchs, Evelyn; Lennartz, Christian; Andrienko, Denis

2012-08-22

The use of blue phosphorescent emitters in organic light-emitting diodes (OLEDs) imposes demanding requirements on a host material. Among these are large triplet energies, the alignment of levels with respect to the emitter, the ability to form and sustain amorphous order, material processability, and an adequate charge carrier mobility. A possible design strategy is to choose a π-conjugated core with a high triplet level and to fulfill the other requirements by using suitable substituents. Bulky substituents, however, induce large spatial separations between conjugated cores, can substantially reduce intermolecular electronic couplings, and decrease the charge mobility of the host. In this work we analyze charge transport in amorphous 2,8-bis(triphenylsilyl)dibenzofuran, an electron-transporting material synthesized to serve as a host in deep-blue OLEDs. We show that mesomeric effects delocalize the frontier orbitals over the substituents recovering strong electronic couplings and lowering reorganization energies, especially for electrons, while keeping energetic disorder small. Admittance spectroscopy measurements reveal that the material has indeed a high electron mobility and a small Poole-Frenkel slope, supporting our conclusions. By linking electronic structure, molecular packing, and mobility, we provide a pathway to the rational design of hosts with high charge mobilities.
Fabrication and Analysis of a Selectively Contacted Dual Channel High Electron Mobility Field-Effect Transistor

NASA Astrophysics Data System (ADS)

Khanna, Ravi

1992-01-01

A selectively contacted dual-channel high electron mobility transistor (SCD-CHEMT) has been designed, fabricated, and electrically characterized, in order to better understand the properties of two layers of two-dimensional electron gases (2DEGs) confined within a quantum well. The 2DEGs are placed under a Schottky barrier control gate which modulates their sheet charge densities, and by use of auxiliary Schottky barrier gates and two levels of ohmic contacts, electrical contacts to the individual channels in which each 2DEG resides is achieved. The design of the dual channel FET structure, and its practical realization by recourse to process development and fabrication are described, as are the techniques, results, and interpretations of electrical characterizations used to analyze the completed device. Critical fabrication procedures involving photolithography, etching, deposition, shallow and deep ohmic contact formation, and gate formation are developed, and a simple technique to reduce gate leakage by photo-oxidation is demonstrated. Analysis of the completed device is performed using one-dimensional band diagram simulations, magnetotransport and electrical measurements. Magnetotransport studies establish the existence of two 2DEGs within the quantum well at 4K. Drain current vs. drain voltage, and transconductance vs. gate voltage characteristics at room temperature confirm the presence of two 2DEGs and show that current flow between them occurs easily at room temperature. Carrier electron mobility profiles are taken of the 2DEGs and show that the lower 2DEG has a mobility comparable to that of a 2DEG formed at a normal interface, indicating that the "inverted interface problem" has been overcome. Capacitance vs. gate voltage measurements are taken, which are consistent with a simple device model consisting of gate depletion and interelectrode parasitic capacitances. It is concluded from the analysis that the dual channel system resides in three basic states: (1) Both channels are occupied by 2DEGs or (2) The upper channel is depleted, or (3) Both channels depleted. Finally, increase in isolation between the two 2DEGs is dramatically demonstrated at 77K by the drain current vs. drain voltage, and transconductance vs. gate voltage characteristics.
Diverse carrier mobility of monolayer BNC x : a combined density functional theory and Boltzmann transport theory study.

PubMed

Wu, Tao; Deng, Kaiming; Deng, Weiqiao; Lu, Ruifeng

2017-10-19

BNC x monolayer as a kind of two-dimensional material has numerous chemical atomic ratios and arrangements with different electronic structures. Via calculations on the basis of density functional theory and Boltzmann transport theory under deformation potential approximation, the band structures and carrier mobilities of BNC x (x = 1,2,3,4) nanosheets are systematically investigated. The calculated results show that BNC 2 -1 is a material with very small band gap (0.02 eV) among all the structures while other BNC x monolayers are semiconductors with band gap ranging from 0.51 eV to 1.32 eV. The carrier mobility of BNC x varies considerably from tens to millions of cm 2 V -1 s -1 . For BNC 2 -1, the hole mobility and electron mobility along both x and y directions can reach 10 5 orders of magnitude, which is similar to the carrier mobility of graphene. Besides, all studied BNC x monolayers obviously have anisotropic hole mobility and electron mobility. In particular, for semiconductor BNC 4 , its hole mobility along the y direction and electron mobility along the x direction unexpectedly reach 10 6 orders of magnitude, even higher than that of graphene. Our findings suggest that BNC x layered materials with the proper ratio and arrangement of carbon atoms will possess desirable charge transport properties, exhibiting potential applications in nanoelectronic devices.
Diverse carrier mobility of monolayer BNC x : a combined density functional theory and Boltzmann transport theory study

NASA Astrophysics Data System (ADS)

Wu, Tao; Deng, Kaiming; Deng, Weiqiao; Lu, Ruifeng

2017-11-01

BNC x monolayer as a kind of two-dimensional material has numerous chemical atomic ratios and arrangements with different electronic structures. Via calculations on the basis of density functional theory and Boltzmann transport theory under deformation potential approximation, the band structures and carrier mobilities of BNC x (x = 1,2,3,4) nanosheets are systematically investigated. The calculated results show that BNC2-1 is a material with very small band gap (0.02 eV) among all the structures while other BNC x monolayers are semiconductors with band gap ranging from 0.51 eV to 1.32 eV. The carrier mobility of BNC x varies considerably from tens to millions of cm2 V-1 s-1. For BNC2-1, the hole mobility and electron mobility along both x and y directions can reach 105 orders of magnitude, which is similar to the carrier mobility of graphene. Besides, all studied BNC x monolayers obviously have anisotropic hole mobility and electron mobility. In particular, for semiconductor BNC4, its hole mobility along the y direction and electron mobility along the x direction unexpectedly reach 106 orders of magnitude, even higher than that of graphene. Our findings suggest that BNC x layered materials with the proper ratio and arrangement of carbon atoms will possess desirable charge transport properties, exhibiting potential applications in nanoelectronic devices.
Correlation between mobility collapse and carbon impurities in Si-doped GaN grown by low pressure metalorganic chemical vapor deposition

NASA Astrophysics Data System (ADS)

Kaess, Felix; Mita, Seiji; Xie, Jingqiao; Reddy, Pramod; Klump, Andrew; Hernandez-Balderrama, Luis H.; Washiyama, Shun; Franke, Alexander; Kirste, Ronny; Hoffmann, Axel; Collazo, Ramón; Sitar, Zlatko

2016-09-01

In the low doping range below 1 × 1017 cm-3, carbon was identified as the main defect attributing to the sudden reduction of the electron mobility, the electron mobility collapse, in n-type GaN grown by low pressure metalorganic chemical vapor deposition. Secondary ion mass spectroscopy has been performed in conjunction with C concentration and the thermodynamic Ga supersaturation model. By controlling the ammonia flow rate, the input partial pressure of Ga precursor, and the diluent gas within the Ga supersaturation model, the C concentration in Si-doped GaN was controllable from 6 × 1019 cm-3 to values as low as 2 × 1015 cm-3. It was found that the electron mobility collapsed as a function of free carrier concentration, once the Si concentration closely approached the C concentration. Lowering the C concentration to the order of 1015 cm-3 by optimizing Ga supersaturation achieved controllable free carrier concentrations down to 5 × 1015 cm-3 with a peak electron mobility of 820 cm2/V s without observing the mobility collapse. The highest electron mobility of 1170 cm2/V s was obtained even in metalorganic vapor deposition-grown GaN on sapphire substrates by optimizing growth parameters in terms of Ga supersaturation to reduce the C concentration.
Electrical properties and subband occupancy at the (La ,Sr ) (Al ,Ta ) O3/SrTi O3 interface

NASA Astrophysics Data System (ADS)

Han, K.; Huang, Z.; Zeng, S. W.; Yang, M.; Li, C. J.; Zhou, W. X.; Wang, X. Renshaw; Venkatesan, T.; Coey, J. M. D.; Goiran, M.; Escoffier, W.; Ariando

2017-06-01

The quasi-two-dimensional electron gas at oxide interfaces provides a platform for investigating quantum phenomena in strongly correlated electronic systems. Here, we study the transport properties at the high-mobility (L a0.3S r0.7 ) (A l0.65T a0.35 ) O3/SrTi O3 interface. Before oxygen annealing, the as-grown interface exhibits a high electron density and electron occupancy of two subbands: higher-mobility electrons (μ1≈104c m2V-1s-1 at 2 K) occupy the lower-energy 3 dxy subband, while lower-mobility electrons (μ1≈103c m2V-1s-1 at 2 K) propagate in the higher-energy 3 dxz /yz -dominated subband. After removing oxygen vacancies by annealing in oxygen, only a single type of 3 dxy electrons remain at the annealed interface, showing tunable Shubnikov-de Haas oscillations below 9 T at 2 K and an effective mass of 0.7 me . By contrast, no oscillation is observed at the as-grown interface even when electron mobility is increased to 50 000 c m2V-1s-1 by gating voltage. Our results reveal the important roles of both carrier mobility and subband occupancy in tuning the quantum transport at oxide interfaces.
Electron and hole transport in ambipolar, thin film pentacene transistors

NASA Astrophysics Data System (ADS)

Saudari, Sangameshwar R.; Kagan, Cherie R.

2015-01-01

Solution-processed, ambipolar, thin-film pentacene field-effect transistors were employed to study both electron and hole transport simultaneously in a single, organic solid-state device. Electron and hole mobilities were extracted from the respective unipolar saturation regimes and show thermally activated behavior and gate voltage dependence. We fit the gate voltage dependent saturation mobility to a power law to extract the characteristic Meyer-Neldel (MN) energy, a measure of the width of the exponential distribution of localized states extending into the energy gap of the organic semiconductor. The MN energy is ˜78 and ˜28 meV for electrons and holes, respectively, which reflects a greater density of localized tail states for electrons than holes. This is consistent with the lower measured electron than hole mobility. For holes, the well-behaved linear regime allows for four-point probe measurement of the contact resistance independent mobility and separate characterization of the width of the localized density of states, yielding a consistent MN energy of 28 meV.
Social Dynamics within Electronic Networks of Practice

ERIC Educational Resources Information Center

Mattson, Thomas A., Jr.

2013-01-01

Electronic networks of practice (eNoP) are special types of electronic social structures focused on discussing domain-specific problems related to a skill-based craft or profession in question and answer style forums. eNoP have implemented peer-to-peer feedback systems in order to motivate future contributions and to distinguish contribution…
The prevention of electronical breakdown and electrostatic voltage problems in the space shuttle and its payloads. Part 2: Design guides and operations considerations

NASA Technical Reports Server (NTRS)

Whitson, D. W.

1975-01-01

The specific electrical discharge problems that can directly affect the shuttle vehicle and its payloads are addressed. General design guidelines are provided to assist flight hardware managers in minimizing these kinds of problems. Specific data are included on workmanship practices and system testing while in low pressure environments. Certain electrical discharge problems that may be unique to the design of the shuttle vehicle itself and to its various mission operational models are discussed.
75 FR 4583 - In the Matter of: Certain Electronic Devices, Including Mobile Phones, Portable Music Players...

Federal Register 2010, 2011, 2012, 2013, 2014

2010-01-28

..., Including Mobile Phones, Portable Music Players, and Computers; Notice of Investigation AGENCY: U.S... music players, and computers, by reason of infringement of certain claims of U.S. Patent Nos. 6,714,091... importation of certain electronic devices, including mobile phones, portable music players, or computers that...
Absorption and Reflection Experiments on High-Mobility 2DEGs in the Regime of Microwave-Induced Resistance Oscillations

NASA Astrophysics Data System (ADS)

Studenikin, S. A.; Potemski, M.; Sachrajda, A. S.; Hilke, M.; Pfeiffer, L. N.; West, K. W.

2005-04-01

We have performed microwave absorption and near-field reflection experiments on a high mobility GaAs/AlGaAs heterostructure for the same conditions for which Microwave-Induced Resistance Oscillations (MIROs) are observed. It is shown that the electrodynamic aspect of the problem is important in these experiments. In the absorption experiments a broad CR line was observed due to a large reflection from the highly conductive electron gas. There were no additional features observed related to absorption at harmonics of the cyclotron resonance. In near-field reflection experiments a very different oscillation pattern was revealed when compared to MIROs. The oscillation pattern observed in the reflection experiments is probably due to plasma effects occurring in a finite-size sample. The whole microscopic picture of MIROs is more complicated than simply a resonant absorption at harmonics of the cyclotron resonance. Nevertheless, the experimental observations are in good agreement with the model by Durst et al. involving the photo-assisted scattering in the presence of a crossed magnetic field and dc bias. The observed damping factor of MIROs may be attributed to a change in the electron mobility as a function of temperature. MIROs may be considered as a light-induced drift effect, a broad class of phenomena associated with a light-induced asymmetry in the velocity distribution function.
Absorption and Reflection Experiments on High-Mobility 2DEGs in the Regime of Microwave-Induced Resistance Oscillations

NASA Astrophysics Data System (ADS)

Studenikin, S. A.; Potemski, M.; Sachrajda, A. S.; Hilke, M.; Pfeiffer, L. N.; West, K. W.

We have performed microwave absorption and near-field reflection experiments on a high mobility GaAs/AlGaAs heterostructure for the same conditions for which Microwave-Induced Resistance Oscillations (MIROs) are observed. It is shown that the electrodynamic aspect of the problem is important in these experiments. In the absorption experiments a broad CR line was observed due to a large reflection from the highly conductive electron gas. There were no additional features observed related to absorption at harmonics of the cyclotron resonance. In near-field reflection experiments a very different oscillation pattern was revealed when compared to MIROs. The oscillation pattern observed in the reflection experiments is probably due to plasma effects occurring in a finite-size sample. The whole microscopic picture of MIROs is more complicated than simply a resonant absorption at harmonics of the cyclotron resonance. Nevertheless, the experimental observations are in good agreement with the model by Durst et al. involving the photo-assisted scattering in the presence of a crossed magnetic field and dc bias. The observed damping factor of MIROs may be attributed to a change in the electron mobility as a function of temperature. MIROs may be considered as a light-induced drift effect, a broad class of phenomena associated with a light-induced asymmetry in the velocity distribution function.
Magnetization processes and existence of reentrant phase transitions in coupled spin-electron model on doubly decorated planar lattices

NASA Astrophysics Data System (ADS)

Čenčariková, Hana; Strečka, Jozef; Gendiar, Andrej

2018-04-01

An alternative model for a description of magnetization processes in coupled 2D spin-electron systems has been introduced and rigorously examined using the generalized decoration-iteration transformation and the corner transfer matrix renormalization group method. The model consists of localized Ising spins placed on nodal lattice sites and mobile electrons delocalized over the pairs of decorating sites. It takes into account a hopping term for mobile electrons, the Ising coupling between mobile electrons and localized spins as well as the Zeeman term acting on both types of particles. The ground-state and finite-temperature phase diagrams were established and comprehensively analyzed. It was found that the ground-state phase diagrams are very rich depending on the electron hopping and applied magnetic field. The diversity of magnetization curves can be related to intermediate magnetization plateaus, which may be continuously tuned through the density of mobile electrons. In addition, the existence of several types of reentrant phase transitions driven either by temperature or magnetic field was proven.

Extreme mobility enhancement of two-dimensional electron gases at oxide interfaces by charge-transfer-induced modulation doping

NASA Astrophysics Data System (ADS)

Chen, Y. Z.; Trier, F.; Wijnands, T.; Green, R. J.; Gauquelin, N.; Egoavil, R.; Christensen, D. V.; Koster, G.; Huijben, M.; Bovet, N.; Macke, S.; He, F.; Sutarto, R.; Andersen, N. H.; Sulpizio, J. A.; Honig, M.; Prawiroatmodjo, G. E. D. K.; Jespersen, T. S.; Linderoth, S.; Ilani, S.; Verbeeck, J.; van Tendeloo, G.; Rijnders, G.; Sawatzky, G. A.; Pryds, N.

2015-08-01

Two-dimensional electron gases (2DEGs) formed at the interface of insulating complex oxides promise the development of all-oxide electronic devices. These 2DEGs involve many-body interactions that give rise to a variety of physical phenomena such as superconductivity, magnetism, tunable metal-insulator transitions and phase separation. Increasing the mobility of the 2DEG, however, remains a major challenge. Here, we show that the electron mobility is enhanced by more than two orders of magnitude by inserting a single-unit-cell insulating layer of polar La1-xSrxMnO3 (x = 0, 1/8, and 1/3) at the interface between disordered LaAlO3 and crystalline SrTiO3 produced at room temperature. Resonant X-ray spectroscopy and transmission electron microscopy show that the manganite layer undergoes unambiguous electronic reconstruction, leading to modulation doping of such atomically engineered complex oxide heterointerfaces. At low temperatures, the modulation-doped 2DEG exhibits Shubnikov-de Haas oscillations and fingerprints of the quantum Hall effect, demonstrating unprecedented high mobility and low electron density.
Universal Correlation between Flatband Voltage and Electron Mobility in TiN/HfSiON Devices with MgO or La2O3 Incorporation and Stack Variation

NASA Astrophysics Data System (ADS)

Mise, Nobuyuki; Kadoshima, Masaru; Morooka, Tetsu; Eimori, Takahisa; Nara, Yasuo; Ohji, Yuzuru

2008-10-01

We investigated the controversial effective workfunction and electron mobility of TiN/HfSiON devices by intentionally adding MgO or La2O3 into HfSiON and by changing the material on TiN or the TiN thickness. As a result, we found a close relationship between the electron mobility at low effective field and the flatband voltage. This relationship is explained on the basis of the fixed charge in HfSiON and its neutralization. The intrinsic workfunction of TiN/HfSiON without charge is determined to be 4.3 eV from the flatband voltage when the electron mobility at low effective field is the highest.
Open-source mobile digital platform for clinical trial data collection in low-resource settings.

PubMed

van Dam, Joris; Omondi Onyango, Kevin; Midamba, Brian; Groosman, Nele; Hooper, Norman; Spector, Jonathan; Pillai, Goonaseelan Colin; Ogutu, Bernhards

2017-02-01

Governments, universities and pan-African research networks are building durable infrastructure and capabilities for biomedical research in Africa. This offers the opportunity to adopt from the outset innovative approaches and technologies that would be challenging to retrofit into fully established research infrastructures such as those regularly found in high-income countries. In this context we piloted the use of a novel mobile digital health platform, designed specifically for low-resource environments, to support high-quality data collection in a clinical research study. Our primary aim was to assess the feasibility of a using a mobile digital platform for clinical trial data collection in a low-resource setting. Secondarily, we sought to explore the potential benefits of such an approach. The investigative site was a research institute in Nairobi, Kenya. We integrated an open-source platform for mobile data collection commonly used in the developing world with an open-source, standard platform for electronic data capture in clinical trials. The integration was developed using common data standards (Clinical Data Interchange Standards Consortium (CDISC) Operational Data Model), maximising the potential to extend the approach to other platforms. The system was deployed in a pharmacokinetic study involving healthy human volunteers. The electronic data collection platform successfully supported conduct of the study. Multidisciplinary users reported high levels of satisfaction with the mobile application and highlighted substantial advantages when compared with traditional paper record systems. The new system also demonstrated a potential for expediting data quality review. This pilot study demonstrated the feasibility of using a mobile digital platform for clinical research data collection in low-resource settings. Sustainable scientific capabilities and infrastructure are essential to attract and support clinical research studies. Since many research structures in Africa are being developed anew, stakeholders should consider implementing innovative technologies and approaches.
Achieving high field-effect mobility in amorphous indium-gallium-zinc oxide by capping a strong reduction layer.

PubMed

Zan, Hsiao-Wen; Yeh, Chun-Cheng; Meng, Hsin-Fei; Tsai, Chuang-Chuang; Chen, Liang-Hao

2012-07-10

An effective approach to reduce defects and increase electron mobility in a-IGZO thin-film transistors (a-IGZO TFTs) is introduced. A strong reduction layer, calcium, is capped onto the back interface of a-IGZO TFT. After calcium capping, the effective electron mobility of a-IGZO TFT increases from 12 cm(2) V(-1) s(-1) to 160 cm(2) V(-1) s(-1). This high mobility is a new record, which implies that the proposed defect reduction effect is key to improve electron transport in oxide semiconductor materials. Copyright © 2012 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.
Theoretical study of the two-dimensional electron mobility in strained III-nitride heterostructures

NASA Astrophysics Data System (ADS)

Yu, Tsung-Hsing; Brennan, Kevin F.

2001-04-01

We present calculations of the two-dimensional (2D) electron mobility in III-nitride heterojunction structures in the presence of spontaneous and piezoelectrically induced polarization effects. The calculations are made using a self-consistent solution of the Schrödinger, Poisson, charge and potential balance equations. It is found that the polarization fields act to significantly increase the 2D sheet charge concentration while reducing the mobility. The mobility reduction results from the enhanced band bending and subsequent attraction of the electrons to the heterointerface where they experience increased surface roughness scattering. Good agreement is obtained between the theoretical calculations and experimental measurements over the full temperature range examined. Comparison of the mobility in InGaN/GaN to AlGaN/GaN heterostructures is made. It is found that the mobility is significantly higher in the InGaN/GaN structure than in the AlGaN/GaN structure.
Benchmarking desktop and mobile handwriting across COTS devices: The e-BioSign biometric database

PubMed Central

Tolosana, Ruben; Vera-Rodriguez, Ruben; Fierrez, Julian; Morales, Aythami; Ortega-Garcia, Javier

2017-01-01

This paper describes the design, acquisition process and baseline evaluation of the new e-BioSign database, which includes dynamic signature and handwriting information. Data is acquired from 5 different COTS devices: three Wacom devices (STU-500, STU-530 and DTU-1031) specifically designed to capture dynamic signatures and handwriting, and two general purpose tablets (Samsung Galaxy Note 10.1 and Samsung ATIV 7). For the two Samsung tablets, data is collected using both pen stylus and also the finger in order to study the performance of signature verification in a mobile scenario. Data was collected in two sessions for 65 subjects, and includes dynamic information of the signature, the full name and alpha numeric sequences. Skilled forgeries were also performed for signatures and full names. We also report a benchmark evaluation based on e-BioSign for person verification under three different real scenarios: 1) intra-device, 2) inter-device, and 3) mixed writing-tool. We have experimented the proposed benchmark using the main existing approaches for signature verification: feature- and time functions-based. As a result, new insights into the problem of signature biometrics in sensor-interoperable scenarios have been obtained, namely: the importance of specific methods for dealing with device interoperability, and the necessity of a deeper analysis on signatures acquired using the finger as the writing tool. This e-BioSign public database allows the research community to: 1) further analyse and develop signature verification systems in realistic scenarios, and 2) investigate towards a better understanding of the nature of the human handwriting when captured using electronic COTS devices in realistic conditions. PMID:28475590
Benchmarking desktop and mobile handwriting across COTS devices: The e-BioSign biometric database.

PubMed

Tolosana, Ruben; Vera-Rodriguez, Ruben; Fierrez, Julian; Morales, Aythami; Ortega-Garcia, Javier

2017-01-01

This paper describes the design, acquisition process and baseline evaluation of the new e-BioSign database, which includes dynamic signature and handwriting information. Data is acquired from 5 different COTS devices: three Wacom devices (STU-500, STU-530 and DTU-1031) specifically designed to capture dynamic signatures and handwriting, and two general purpose tablets (Samsung Galaxy Note 10.1 and Samsung ATIV 7). For the two Samsung tablets, data is collected using both pen stylus and also the finger in order to study the performance of signature verification in a mobile scenario. Data was collected in two sessions for 65 subjects, and includes dynamic information of the signature, the full name and alpha numeric sequences. Skilled forgeries were also performed for signatures and full names. We also report a benchmark evaluation based on e-BioSign for person verification under three different real scenarios: 1) intra-device, 2) inter-device, and 3) mixed writing-tool. We have experimented the proposed benchmark using the main existing approaches for signature verification: feature- and time functions-based. As a result, new insights into the problem of signature biometrics in sensor-interoperable scenarios have been obtained, namely: the importance of specific methods for dealing with device interoperability, and the necessity of a deeper analysis on signatures acquired using the finger as the writing tool. This e-BioSign public database allows the research community to: 1) further analyse and develop signature verification systems in realistic scenarios, and 2) investigate towards a better understanding of the nature of the human handwriting when captured using electronic COTS devices in realistic conditions.
Germanium CMOS potential from material and process perspectives: Be more positive about germanium

NASA Astrophysics Data System (ADS)

Toriumi, Akira; Nishimura, Tomonori

2018-01-01

CMOS miniaturization is now approaching the sub-10 nm level, and further downscaling is expected. This size scaling will end sooner or later, however, because the typical size is approaching the atomic distance level in crystalline Si. In addition, it is said that electron transport in FETs is ballistic or nearly ballistic, which means that the injection velocity at the virtual source is a physical parameter relevant for estimating the driving current. Channel-materials with higher carrier mobility than Si are nonetheless needed, and the carrier mobility in the channels is a parameter important with regard to increasing the injection velocity. Although the density of states in the channel has not been discussed often, it too is relevant for estimating the channel current. Both the mobility and the density of states are in principle related to the effective mass of the carrier. From this device physics viewpoint, we expect germanium (Ge) CMOS to be promising for scaling beyond the Si CMOS limit because the bulk mobility values of electrons and holes in Ge are much higher than those of electrons and holes in Si, and the electron effective mass in Ge is not much less than that in III-V compounds. There is a debate that Ge should be used for p-MOSFETs and III-V compounds for n-MOSFETs, but considering that the variability or nonuniformity of the FET performance in today’s CMOS LSIs is a big challenge, it seems that much more attention should be paid to the simplicity of the material design and of the processing steps. Nevertheless, Ge faces a number of challenges even in case that only the FET level is concerned. One of the big problems with Ge CMOS technology has been its poor performance in n-MOSFETs. While the hole mobility in p-FETs has been improved, the electron mobility in the inversion layer of Ge FETs remains a serious concern. If this is due to the inherent properties of Ge, only p-MOSFETs might be used for device applications. To make Ge CMOS devices practically viable, we need to understand why electron mobility is severely degraded in the inversion layer in Ge n-channel MOSFETs and to find out how it can be increased. In the Si CMOS technology, the SiO2/Si interface has long been investigated and cannot be ignored even after the introduction of high-k gate stack technology. In that sense, the GeO2/Ge interface should be intensively studied to make the best of Ge’s advantages. Therefore we first discuss the GeO2/Ge interface with regard to its physical and electrical characteristics. When we regard Ge as a channel material beyond Si for high performance ULSIs, we also have to seriously consider the gate stack scalability and reliability. The source/drain engineering, as well as the gate stack formation, is another challenge in Ge MOSFET design. Both the higher metal/Ge contact resistance and the larger p/n junction leakage current may be the consequences of Ge’s intrinsic properties because they are derived from the strong Fermi-level pinning and the narrow energy band gap, respectively. Even if the carrier transport in the channel may be ideally ballistic, these properties should degrade FET properties. The narrower energy band gap of Ge is often addressed, but the higher dielectric constant of Ge is rarely discussed. This is also the case for most of the other high-mobility materials. The dielectric constant is directly and negatively related to short-channel effects, and we have not been able to provide a substantial solution to overcome this hardship. We have to keep this in mind for the short-channel FET operation. Although a number of problems remain to be solved, in this paper, we view the current status of Ge FET technology positively. A number of (but not all) Ge-related challenges have been overcome in the past 10 years, which seems to be a good time to summarize the status of Ge technology, particularly materials engineering aspects rather than device integration issues. Since we cannot cover all of the results published to date, we mainly discuss fundamental aspects based on our experimental results. Remaining challenges are also addressed but not comprehensively. Integration issues are not discussed in this review. Finally, new types of electron devices utilizing Ge’s advantages are briefly introduced on the basis of our experimental results.
Mobile Health Technology Using a Wearable Sensorband for Female College Students With Problem Drinking: An Acceptability and Feasibility Study

PubMed Central

Silverman, Michelle; Sherpa, Dawa Phuti; Naegle, Madeline A; Kim, Hyorim; Coffman, Donna L; Ferdschneider, Marcy

2017-01-01

Background An increasing number of mobile app interventions have been developed for problem drinking among college students; however, few studies have examined the integration of a mobile app with continuous physiological monitoring and alerting of affective states related to drinking behaviors. Objective The aim of this paper was to evaluate the acceptability and feasibility of Mind the Moment (MtM), a theoretically based intervention for female college students with problem drinking that combines brief, in-person counseling with ecological momentary intervention (EMI) on a mobile app integrated with a wearable sensorband. Methods We recruited 10 non-treatment seeking, female undergraduates from a university health clinic who scored a 3 or higher on the Alcohol Use Disorders Identification Test–Consumption (AUDIT-C) to participate in this pilot study. Study activities involved an in-person baseline intake and 1 follow-up assessment, 2 in-person alcohol brief intervention counseling sessions, and use of MtM technology components (sensorband and EMI on a mobile app) for approximately 3-4 weeks. The intervention used motivational interviewing (MI) and cognitive behavioral therapy (CBT) strategies for reducing risks associated with drinking. We used both qualitative and quantitative assessments to measure acceptability of the intervention and feasibility of delivery. Use patterns of the sensorband and mobile app were also collected. Results Quantitative and qualitative data indicated high levels of acceptability for the MtM intervention. Altogether, participants made reports on the app on 26.7% (78/292) the days the technology was available to them and completed a total of 325 reports with wide variation between participants. Qualitative findings indicated that sensorband-elicited alerts promoted an increase in awareness of thoughts, feelings, and behaviors related to current environmental stressors and drinking behaviors in theoretically meaningful ways. Specific challenges related to functionality and form of the sensorband were identified. Conclusions Delivering intervention material “just-in-time,” at the moment participants need to use behavioral strategies has great potential to individualize behavioral interventions for reducing problem drinking and other health behaviors. These findings provide initial evidence for the promise of wearable sensors for increasing potency of theoretically grounded mobile health interventions and point to directions for future research and uptake of these technologies. PMID:28687533
Carrier mobility degradation due to high dose implantation in ultrathin unstrained and strained silicon-on-insulator films

NASA Astrophysics Data System (ADS)

Dupré, C.; Ernst, T.; Hartmann, J.-M.; Andrieu, F.; Barnes, J.-P.; Rivallin, P.; Faynot, O.; Deleonibus, S.; Fazzini, P. F.; Claverie, A.; Cristoloveanu, S.; Ghibaudo, G.; Cristiano, F.

2007-11-01

Based on electrical measurements and transmission electron microscopy (TEM) imaging, we propose an explanation for the electron and hole mobility degradation with gate length reduction in metal-oxide-semiconductor field effect transistors (MOSFETs). We demonstrate that ion implantation, normally used for source/drain doping, is responsible for transport degradation for short-channel devices. Implantation impact on electrons and holes mobility was investigated both on silicon-on-insulator (SOI) and tensile strained silicon-on-insulator (sSOI) substrates. Wafers with ultrathin Si films (from 8 to 35 nm) were Ge implanted at 3 keV and various concentrations (from 5×1014 to 2×1015 atoms cm-2), then annealed at 600 °C for 1 h. Secondary ion mass spectrometry enabled us to quantify the Ge-implanted atoms concentrations. The end-of-range defects impact on mobility was investigated with the pseudo-MOSFET technique. Measurements showed a mobility decrease as the implantation dose increased. We demonstrated that sSOI mobility is more sensitive to implantation than SOI mobility, without any implantation-induced strain relaxation in sSOI (checked using the ultraviolet Raman technique). A 36% (25%) holes (electrons) mobility degradation was measured for sSOI, while SOI presented a 21% mobility degradation for holes and 5% for electrons. Finally, the electrical results were compared with morphological studies. Plan-view TEM showed the presence of interstitial defects formed during ion implantation and annealing. The defect density was estimated to be two times higher in sSOI than in SOI, which is in full agreement with electrical results mentioned before. The results are relevant for the optimization of the source and drain regions of advanced nanoscale SOI and sSOI transistors.
GSM-PKI solution enabling secure mobile communications.

PubMed

Jelekäinen, Pekka

2004-03-31

Because of its wide distribution and ease of use, the mobile phone, as a reliable personal communications channel, offers an excellent basis for the provision of reliable electronic communications services. In Finland, ca. 75% of the citizens have a mobile phone and, at present and most likely also in the future, it is the most widely spread service channel allowing reliable electronic communications. Despite the restricted functions of the mobile phone, the citizens can use the phone also as a communications medium. In 2001, the Finns sent over 1 billion SMS messages. In Finland, TeliaSonera Finland Oyi and the Population Register Centre (PRC) have closed a co-operation agreement with the aim of creating a mobile phone service for the electronic identification of a person. The co-operation launched is a significant development project from the perspective of the citizens. As a result, the consumers will have a new alternative for reliable electronic communications and commerce in data networks in addition to the electronic identification card. In the future, it will be possible to use the services of both public administration and the private sector by means of a mobile phone more reliably than before, without a physical visit, e.g. to a health centre or to another provider of healthcare services. The possibility of identification and signature by a mobile phone allows an easier provision of versatile services irrespective of time and place, because, in addition to voice, text message, and WAP functions, the service can be utilised also in communications services through the Internet, in which case, the mobile phone acts like a card reader. From the perspective of reliable personal mobile communications, the healthcare sector is one of the most significant and challenging application areas.
Transforming clinical imaging and 3D data for virtual reality learning objects: HTML5 and mobile devices implementation.

PubMed

Trelease, Robert B; Nieder, Gary L

2013-01-01

Web deployable anatomical simulations or "virtual reality learning objects" can easily be produced with QuickTime VR software, but their use for online and mobile learning is being limited by the declining support for web browser plug-ins for personal computers and unavailability on popular mobile devices like Apple iPad and Android tablets. This article describes complementary methods for creating comparable, multiplatform VR learning objects in the new HTML5 standard format, circumventing platform-specific limitations imposed by the QuickTime VR multimedia file format. Multiple types or "dimensions" of anatomical information can be embedded in such learning objects, supporting different kinds of online learning applications, including interactive atlases, examination questions, and complex, multi-structure presentations. Such HTML5 VR learning objects are usable on new mobile devices that do not support QuickTime VR, as well as on personal computers. Furthermore, HTML5 VR learning objects can be embedded in "ebook" document files, supporting the development of new types of electronic textbooks on mobile devices that are increasingly popular and self-adopted for mobile learning. © 2012 American Association of Anatomists.
A study on the electron transport properties of ZnON semiconductors with respect to the relative anion content

PubMed Central

Park, Jozeph; Kim, Yang Soo; Ok, Kyung-Chul; Park, Yun Chang; Kim, Hyun You; Park, Jin-Seong; Kim, Hyun-Suk

2016-01-01

High-mobility zinc oxynitride (ZnON) semiconductors were grown by RF sputtering using a Zn metal target in a plasma mixture of Ar, N2, and O2 gas. The RF power and the O2 to N2 gas flow rates were systematically adjusted to prepare a set of ZnON films with different relative anion contents. The carrier density was found to be greatly affected by the anion composition, while the electron mobility is determined by a fairly complex mechanism. First-principles calculations indicate that excess vacant nitrogen sites (VN) in N-rich ZnON disrupt the local electron conduction paths, which may be restored by having oxygen anions inserted therein. The latter are anticipated to enhance the electron mobility, and the exact process parameters that induce such a phenomenon can only be found experimentally. Contour plots of the Hall mobility and carrier density with respect to the RF power and O2 to N2 gas flow rate ratio indicate the existence of an optimum region where maximum electron mobility is obtained. Using ZnON films grown under the optimum conditions, the fabrication of high-performance devices with field-effect mobility values exceeding 120 cm2/Vs is demonstrated based on simple reactive RF sputtering methods. PMID:27098656
Accessing and operating agricultural machinery: Advancements in assistive technology for users with impaired mobility.

PubMed

Ehlers, Shawn G; Field, William E

2018-02-14

This research focused on the advancements made in enabling agricultural workers with impaired mobility to access and operate off-road agricultural machinery. Although not a new concept, technological advancements in remote-controlled lifts, electronic actuators, electric over hydraulic controllers, and various modes of hand controls have advanced significantly, allowing operators with limited mobility to resume a high level of productivity in agricultural-related enterprises. In the United States, approximately 1.7% of the population is living with some form of paralysis or significant mobility impairment. When paired with the 2012 USDA Agriculture Census of 3.2 million farmers, it can be extrapolated that these technologies could impact 54,000 agricultural workers who have encountered disabling injuries or disease, which inhibit their ability to access and operate tractors, combines, and other self-propelled agricultural machines. Advancements in agricultural-specific technologies can allow for many of these individuals to regain the ability to effectively operate machinery once more.
Outdoor motivation moderates the effects of accessibility on mobility in old age.

PubMed

Kamin, Stefan T; Beyer, Anja; Lang, Frieder R

2016-07-01

Mobility plays a major role in healthy aging and social participation. This study explored whether accessibility problems in the housing environment are negatively associated with mobility in old age and whether this association is moderated by differences in an individual's preference for spending time outside the home (outdoor motivation). This article reports the results of a research project on mobility in old age. The project included a survey study of 120 community-dwelling older adults between 59 and 92 years of age (mean = 71.7 years, SD = 7.3 years) living in the metropolitan region of Nuremberg, Germany. Objective assessments were conducted in the participants' housing environment to evaluate the magnitude of accessibility problems. Accessibility problems were negatively associated with mobility. Interaction analyses suggested a buffering effect of outdoor motivation on this association, i.e. participants who reported a preference for spending time outside the home had a higher mobility in the face of accessibility problems as compared with those who preferred staying at home. Outdoor motivation may have protective effects for older adults when accessibility problems challenge mobility. These findings contribute to improving the understanding of how and under what circumstances older adults stay mobile and active in everyday life. Considering interindividual differences in outdoor motivation may binterventions and public health programs that are aimed at enhancing mobility and social participation in old age.
The size-quantized oscillations of the optical-phonon-limited electron mobility in AlN/GaN/AlN nanoscale heterostructures

NASA Astrophysics Data System (ADS)

Pokatilov, E. P.; Nika, D. L.; Askerov, A. S.; Zincenco, N. D.; Balandin, A. A.

2007-12-01

nanometer scale thickness by taking into account multiple quantized electron subbands and the confined optical phonon dispersion. It was shown that the inter-subband electronic transitions play an important role in limiting the electron mobility in the heterostructures when the energy separation between one of the size-quantized excited electron subbands and the Fermi energy becomes comparable to the optical phonon energy. The latter leads to the oscillatory dependence of the electron mobility on the thickness of the heterostructure conduction channel layer. This effect is observable at room temperature and over a wide range of the carrier densities. The developed formalism and calculation procedure are readily applicable to other material systems. The described effect can be used for fine-tuning the confined electron and phonon states in the nanoscale heterostructures in order to achieve performance enhancement of the nanoscale electronic and optoelectronic devices.
Common Principles of Molecular Electronics and Nanoscale Electrochemistry.

PubMed

Bueno, Paulo Roberto

2018-05-24

The merging of nanoscale electronics and electrochemistry can potentially modernize the way electronic devices are currently engineered or constructed. It is well known that the greatest challenges will involve not only miniaturizing and improving the performance of mobile devices, but also manufacturing reliable electrical vehicles, and engineering more efficient solar panels and energy storage systems. These are just a few examples of how technological innovation is dependent on both electrochemical and electronic elements. This paper offers a conceptual discussion of this central topic, with particular focus on the impact that uniting physical and chemical concepts at a nanoscale could have on the future development of electroanalytical devices. The specific example to which this article refers pertains to molecular diagnostics, i.e., devices that employ physical and electrochemical concepts to diagnose diseases.
Transparent amorphous oxide semiconductors for organic electronics: Application to inverted OLEDs

PubMed Central

Hosono, Hideo; Toda, Yoshitake; Kamiya, Toshio; Watanabe, Satoru

2017-01-01

Efficient electron transfer between a cathode and an active organic layer is one key to realizing high-performance organic devices, which require electron injection/transport materials with very low work functions. We developed two wide-bandgap amorphous (a-) oxide semiconductors, a-calcium aluminate electride (a-C12A7:e) and a-zinc silicate (a-ZSO). A-ZSO exhibits a low work function of 3.5 eV and high electron mobility of 1 cm2/(V · s); furthermore, it also forms an ohmic contact with not only conventional cathode materials but also anode materials. A-C12A7:e has an exceptionally low work function of 3.0 eV and is used to enhance the electron injection property from a-ZSO to an emission layer. The inverted electron-only and organic light-emitting diode (OLED) devices fabricated with these two materials exhibit excellent performance compared with the normal type with LiF/Al. This approach provides a solution to the problem of fabricating oxide thin-film transistor-driven OLEDs with both large size and high stability. PMID:28028243
Molecular origin of differences in hole and electron mobility in amorphous Alq3--a multiscale simulation study.

PubMed

Fuchs, Andreas; Steinbrecher, Thomas; Mommer, Mario S; Nagata, Yuki; Elstner, Marcus; Lennartz, Christian

2012-03-28

In order to determine the molecular origin of the difference in electron and hole mobilities of amorphous thin films of Alq(3) (meridional Alq(3) (tris(8-hydroxyquinoline) aluminium)) we performed multiscale simulations covering quantum mechanics, molecular mechanics and lattice models. The study includes realistic disordered morphologies, polarized site energies to describe diagonal disorder, quantum chemically calculated transfer integrals for the off-diagonal disorder, inner sphere reorganization energies and an approximative scheme for outer sphere reorganization energies. Intermolecular transfer rates were calculated via Marcus-theory and mobilities were simulated via kinetic Monte Carlo simulations and by a Master Equation approach. The difference in electron and hole mobility originates from the different localization of charge density in the radical anion (more delocalized) compared to the radical cation (more confined). This results in higher diagonal disorder for holes and less favourable overlap properties for the hole transfer integrals leading to an overall higher electron mobility.
The "EyeCane", a new electronic travel aid for the blind: Technology, behavior & swift learning.

PubMed

Maidenbaum, Shachar; Hanassy, Shlomi; Abboud, Sami; Buchs, Galit; Chebat, Daniel-Robert; Levy-Tzedek, Shelly; Amedi, Amir

2014-01-01

Independent mobility is one of the most pressing problems facing people who are blind. We present the EyeCane, a new mobility aid aimed at increasing perception of environment beyond what is provided by the traditional White Cane for tasks such as distance estimation, navigation and obstacle detection. The "EyeCane" enhances the traditional White Cane by using tactile and auditory output to increase detectable distance and angles. It circumvents the technical pitfalls of other devices, such as weight, short battery life, complex interface schemes, and slow learning curve. It implements multiple beams to enables detection of obstacles at different heights, and narrow beams to provide active sensing that can potentially increase the user's spatial perception of the environment. Participants were tasked with using the EyeCane for several basic tasks with minimal training. Blind and blindfolded-sighted participants were able to use the EyeCane successfully for distance estimation, simple navigation and simple obstacle detection after only several minutes of training. These results demonstrate the EyeCane's potential for mobility rehabilitation. The short training time is especially important since available mobility training resources are limited, not always available, and can be quite expensive and/or entail long waiting periods.

GaN-based sensor nodes for in situ detection of gases

NASA Technical Reports Server (NTRS)

Son, Kyung-Ah (Inventor); Prokopuk, Nicholas (Inventor); Moon, Jeong-Sun (Inventor)

2008-01-01

A system for detecting chemical/biological substances and a detection method. The system comprises a plurality of sensing units or nodes and a radiofrequency link. Each unit has several sensors with different sensing curves. Each sensor is able to transmit information related to the sensed substance on a specific frequency. The sensors preferably comprise AlGaN/GaN high electron mobility transistors.
A smart multisensor approach to assist blind people in specific urban navigation tasks.

PubMed

Ando, B

2008-12-01

Visually impaired people are often discouraged in using electronic aids due to complexity of operation, large amount of training, nonoptimized degree of information provided to the user, and high cost. In this paper, a new multisensor architecture is discussed, which would help blind people to perform urban mobility tasks. The device is based on a multisensor strategy and adopts smart signal processing.
Electron Mobility and Trapping in Ferrihydrite Nanoparticles

DOE Office of Scientific and Technical Information (OSTI.GOV)

Soltis, Jennifer A.; Schwartzberg, Adam M.; Zarzycki, Piotr

Iron is the most abundant transition metal in the Earth's crust, and naturally occurring iron oxide minerals play a commanding role in environmental redox reactions. Although iron oxide redox reactions are well studied, their precise mechanisms are not fully understood. Recent work has shown that these involve electron transfer pathways within the solid, suggesting that overall reaction rates could be dependent on electron mobility. Initial ultrafast spectroscopy studies of iron oxide nanoparticles sensitized by fluorescein derivatives supported a model for electron mobility based on polaronic hopping of electron charge carriers between iron sites, but the constitutive relationships between hopping mobilitiesmore » and interfacial charge transfer processes has remained obscured. We developed a coarse-grained lattice Monte Carlo model to simulate the collective mobilities and lifetimes of these photoinjected electrons with respect to recombination with adsorbed dye molecules for the essential nanophase ferrihydrite, and tested predictions made by the simulations using pump-probe spectroscopy. We acquired optical transient absorption spectra as a function of particle size and under a variety of solution conditions, and used cryogenic transmission electron microscopy to determine the aggregation state of the nanoparticles. We observed biphasic electron recombination kinetics over timescales that spanned picoseconds to microseconds, the slower regime of which was fit with a stretched exponential decay function. The recombination rates were weakly affected by nanoparticle size and aggregation state, suspension pH, and the injection of multiple electrons per nanoparticle. We conclude that electron mobility indeed limits the rate of interfacial electron transfer in these systems with the slowest processes relating to escape from deep traps, the presence of which outweighs the influence of environmental factors such as pH-dependent surface charge.« less
Digital mobile telephones and interference of ophthalmic equipment.

PubMed

Ang, G S; Lian, P; Ng, W S; Whyte, I; Ong, J M

2007-01-01

To assess the effect of mobile telephone electromagnetic interference on electronic ophthalmic equipment. Prospective audit with mobile telephones placed at distances of 3 m, 1 m, and 30 cm from, and in contact with, electronic ophthalmic equipment. Any interruption or cessation of the function of the ophthalmic device was assessed with the mobile telephones in standby, and in dialling or receiving modes. Any alterations of displayed digital figures or numbers were also assessed. A total of 23 electronic ophthalmic devices in two hospital ophthalmology outpatient departments were evaluated. All six mobile telephones used, and 22 (95.7%) of the 23 ophthalmic equipment evaluated had the Conformité Européene (CE) mark. No device showed any interruption or cessation of function. There were no alterations of displayed digital figures or numbers. The only effect of any kind was found with four instruments (1 non-CE marked), where there was temporary flickering on the screen, and only occurred when the mobile telephones were dialling or receiving at a distance of 30 cm or less from the instruments. This study shows that among the electronic ophthalmic devices tested, none suffered failure or interruption of function, from mobile telephone interference. Although not comprehensive for all ophthalmic equipment, the results question the need for a complete ban of mobile telephones in ophthalmic departments. It highlights the need for a controlled, objectively measured study of the clinically relevant effects of mobile telephones in the ophthalmology outpatient setting.
Investigation of plasmonic resonances in the two-dimensional electron gas of an InGaAs/InP high electron mobility transistor

NASA Astrophysics Data System (ADS)

Cleary, Justin W.; Peale, Robert E.; Saxena, Himanshu; Buchwald, Walter R.

2011-05-01

The observation of THz regime transmission resonances in an InGaAs/InP high electron mobility transistor (HEMT) can be attributed to excitation of plasmons in its two-dimensional electron gas (2DEG). Properties of grating-based, gate-voltage tunable resonances are shown to be adequately modeled using commercial finite element method (FEM) software when the HEMT layer structure, gate geometry and sheet charge concentration are taken into account. The FEM results are shown to produce results consistent with standard analytical theories in the 10-100 cm-1 wavenumber range. An original analytic formula presented here describes how the plasmonic resonance may change in the presence of a virtual gate, or region of relatively high free charge carriers that lies in the HEMT between the physical grating gate and the 2DEG. The virtual gate and corresponding analytic formulation are able to account for the red-shifting experimentally observed in plasmonic resonances. The calculation methods demonstrated here have the potential to greatly aid in the design of future detection devices that require specifically tuned plasmonic modes in the 2DEG of a HEMT, as well as giving new insights to aid in the development of more complete analytic theories.
Micro unattended mobility system (MUMS)

NASA Astrophysics Data System (ADS)

Rudakevych, Pavlo; Greiner, Helen; Pletta, Bryan

1999-07-01

This report covers work under phase one of the Micro Unattended Mobility System project investigating the addition of a mobile sensor components to existing and future ground penetrator delivered unattended sensor systems. A typical unattended sensor strategy consists of air-dropping sensor packages into a target terrain for remote observation and intelligence gathering. Existing and planned unattended systems have no control over their location after the drop is complete. We propose to augment the capability of these sensing packages by giving them a degree of local mobility. From an assumed operational scenario, vehicle design specifications are identified that would be required for mission success. Three basic mobility concepts are presented and evaluated for their strengths and weaknesses in the proposed mission. The mobility concepts are grouped into wheeled, jumping, and crawling systems. Of the three mobility concepts discussed, the system that shows the most promise is presented in a more detailed design. This design consists of two side by side wheels which drag a reaction tail behind them. The control electronics, batteries, and drive motors are housed in a central body connected to the tail and two sensor payloads can be placed in the wheel hubs. This design is proposed for further development and testing in the second phase of this project.
Multifunction interferometry using the electron mobility visibility and mean free path relationship.

PubMed

Pornsuwancharoen, N; Youplao, P; Amiri, I S; Aziz, M S; Tran, Q L; Ali, J; Yupapin, P; Grattan, K T V

2018-05-08

A conventional Michelson interferometer is modified and used to form the various types of interferometers. The basic system consists of a conventional Michelson interferometer with silicon-graphene-gold embedded between layers on the ports. When light from the monochromatic source is input into the system via the input port (silicon waveguide), the change in optical path difference (OPD) of light traveling in the stacked layers introduces the change in the optical phase, which affects to the electron mean free path within the gold layer, induces the change in the overall electron mobility can be seen by the interferometer output visibility. Further plasmonic waves are introduced on the graphene thin film and the electron mobility occurred within the gold layer, in which the light-electron energy conversion in terms of the electron mobility can be observed, the gold layer length is 100 nm. The measurement resolution in terms of the OPD of ∼50 nm is achieved. In applications, the outputs of the drop port device of the modified Michelson interferometer can be arranged by the different detectors, where the polarized light outputs, the photon outputs, the electron spin outputs can be obtained by the interference fringe visibility, mobility visibility and the spin up-down splitting output energies. The modified Michelson interferometer theory and the detection schemes are given in details. © 2018 Wiley Periodicals, Inc.
Development and Evaluation of an Interactive Mobile Learning Environment with Shared Display Groupware

ERIC Educational Resources Information Center

Yang, Jie Chi; Lin, Yi Lung

2010-01-01

When using mobile devices in support of learning activities, students gain mobility, but problems arise when group members share information. The small size of the mobile device screen becomes problematic when it is being used by two or more students to share and exchange information. This problem affects interactions among group members. To…
Charge-transfer mobility and electrical conductivity of PANI as conjugated organic semiconductors

NASA Astrophysics Data System (ADS)

Zhang, Yahong; Duan, Yuping; Song, Lulu; Zheng, Daoyuan; Zhang, Mingxing; Zhao, Guangjiu

2017-09-01

The intramolecular charge transfer properties of a phenyl-end-capped aniline tetramer (ANIH) and a chloro-substituted derivative (ANICl) as organic semiconductors were theoretically studied through the first-principles calculation based on the Marcus-Hush theory. The reorganization energies, intermolecular electronic couplings, angular resolution anisotropic mobilities, and density of states of the two crystals were evaluated. The calculated results demonstrate that both ANIH and ANICl crystals show the higher electron transfer mobilities than the hole-transfer mobilities, which means that the two crystals should prefer to function as n-type organic semiconductors. Furthermore, the angle dependence mobilities of the two crystals show remarkable anisotropic character. The maximum mobility μmax of ANIH and ANICl crystals is 1.3893 and 0.0272 cm2 V-1 s-1, which appear at the orientation angles near 176°/356° and 119°/299° of a conducting channel on the a-b reference plane. It is synthetically evaluated that the ANIH crystal possesses relatively lower reorganization energy, higher electronic coupling, and electron transfer mobility, which means that the ANIH crystal may be the more ideal candidate as a high performance n-type organic semiconductor material. The systematic theoretical studies on organic crystals should be conducive to evaluating the charge-transport properties and designing higher performance organic semiconductor materials.
Charge-transfer mobility and electrical conductivity of PANI as conjugated organic semiconductors.

PubMed

Zhang, Yahong; Duan, Yuping; Song, Lulu; Zheng, Daoyuan; Zhang, Mingxing; Zhao, Guangjiu

2017-09-21

The intramolecular charge transfer properties of a phenyl-end-capped aniline tetramer (ANIH) and a chloro-substituted derivative (ANICl) as organic semiconductors were theoretically studied through the first-principles calculation based on the Marcus-Hush theory. The reorganization energies, intermolecular electronic couplings, angular resolution anisotropic mobilities, and density of states of the two crystals were evaluated. The calculated results demonstrate that both ANIH and ANICl crystals show the higher electron transfer mobilities than the hole-transfer mobilities, which means that the two crystals should prefer to function as n-type organic semiconductors. Furthermore, the angle dependence mobilities of the two crystals show remarkable anisotropic character. The maximum mobility μ max of ANIH and ANICl crystals is 1.3893 and 0.0272 cm 2 V -1 s -1 , which appear at the orientation angles near 176°/356° and 119°/299° of a conducting channel on the a-b reference plane. It is synthetically evaluated that the ANIH crystal possesses relatively lower reorganization energy, higher electronic coupling, and electron transfer mobility, which means that the ANIH crystal may be the more ideal candidate as a high performance n-type organic semiconductor material. The systematic theoretical studies on organic crystals should be conducive to evaluating the charge-transport properties and designing higher performance organic semiconductor materials.
High Electron Mobility in SiGe/Si n-MODFET Structures on Sapphire Substrates

NASA Technical Reports Server (NTRS)

Mueller, Carl H.; Croke, Edward T.; Alterovitz, Samuel A.

2003-01-01

For the first time, SiGe/Si n-Modulation Doped Field Effect Transistors (n-MODFET) structures have been grown on sapphire substrates. Room temperature electron mobility value of 1271 square centimeters N-sec at an electron carrier density (n(sub e) = 1.33x10(exp 12) per square centimeter)) of 1.6 x 10(exp 12) per square centimeter was obtained. At 250 mK, the mobility increases to 13,313 square centimeters/V-sec (n(sub e)=1.33x10(exp 12) per square centimeter)) and Shubnikov-de Haas oscillations appear, showing excellent confinement of the two-dimensional electron gas.
Two-dimensional superconducting phase in LaTiO3/SrTiO3 heterostructures induced by high-mobility carrier doping.

PubMed

Biscaras, J; Bergeal, N; Hurand, S; Grossetête, C; Rastogi, A; Budhani, R C; LeBoeuf, D; Proust, C; Lesueur, J

2012-06-15

In this Letter, we show that a superconducting two-dimensional electron gas is formed at the LaTiO3/SrTiO3 interface whose transition temperature can be modulated by a back-gate voltage. The gas consists of two types of carriers: a majority of low-mobility carriers always present, and a few high-mobility ones that can be injected by electrostatic doping. The calculation of the electron spatial distribution in the confinement potential shows that the high-mobility electrons responsible for superconductivity set at the edge of the gas whose extension can be tuned by the field effect.
Division by zero, pseudo-division by zero, Zhang dynamics method and Zhang-gradient method about control singularity conquering

NASA Astrophysics Data System (ADS)

Zhang, Yunong; Zhang, Yinyan; Chen, Dechao; Xiao, Zhengli; Yan, Xiaogang

2017-01-01

In this paper, the division-by-zero (DBO) problem in the field of nonlinear control, which is traditionally termed the control singularity problem (or specifically, controller singularity problem), is investigated by the Zhang dynamics (ZD) method and the Zhang-gradient (ZG) method. According to the impact of the DBO problem on the state variables of the controlled nonlinear system, the concepts of the pseudo-DBO problem and the true-DBO problem are proposed in this paper, which provide a new perspective for the researchers on the DBO problems as well as nonlinear control systems. Besides, the two classes of DBO problems are solved under the framework of the ZG method. Specific examples are shown and investigated in this paper to illustrate the two proposed concepts and the efficacy of the ZG method in conquering pseudo-DBO and true-DBO problems. The application of the ZG method to the tracking control of a two-wheeled mobile robot further substantiates the effectiveness of the ZG method. In addition, the ZG method is successfully applied to the tracking control of a pure-feedback nonlinear system.
Charge Transport in Metal Oxides: A Theoretical Study of Hematite α-Fe2O3

DOE Office of Scientific and Technical Information (OSTI.GOV)

Iordanova, Nellie I.; Dupuis, Michel; Rosso, Kevin M.

2005-04-08

Transport of conduction electrons and holes through the lattice of ??Fe2O3 (hematite) is modeled as a valence alternation of iron cations using ab initio electronic structure calculations and electron transfer theory. Experimental studies have shown that the conductivity along the (001) basal plane is four orders of magnitude larger than the conductivity along the [001] direction. In the context of the small polaron model, a cluster approach was used to compute quantities controlling the mobility of localized electrons and holes, i.e. the reorganization energy and the electronic coupling matrix element that enter Marcus? theory. The calculation of the electronic couplingmore » followed the Generalized Mulliken-Hush approach using the complete active space self-consistent field (CASSCF) method. Our findings demonstrate an approximately three orders of magnitude anisotropy in both electron and hole mobility between directions perpendicular and parallel to the c-axis, in good accord with experimental data. The anisotropy arises from the slowness of both electron and hole mobility across basal oxygen planes relative to that within iron bi-layers between basal oxygen planes. Interestingly, for elementary reaction steps along either of the directions considered, there is only approximately one order of magnitude difference in mobility between electrons and holes, in contrast to accepted classical arguments. Our findings indicate that the most important quantity underlying mobility differences is the electronic coupling, albeit the reorganization energy contributes as well. The large values computed for the electronic coupling suggest that charge transport reactions in hematite are adiabatic in nature. The electronic coupling is found to depend on both the superexchange interaction through the bridging oxygen atoms and the d-shell electron spin coupling within the Fe?Fe donor-acceptor pair, while the reorganization energy is essentially independent of the electron spin coupling.« less
Internet and mobile technologies: addressing the mental health of trauma survivors in less resourced communities.

PubMed

Ruzek, J I; Yeager, C M

2017-01-01

Internet and mobile technologies offer potentially critical ways of delivering mental health support in low-resource settings. Much evidence indicates an enormous negative impact of mental health problems in low- and middle-income countries (LMICs), and many of these problems are caused, or worsened, by exposure to wars, conflicts, natural and human-caused disasters, and other traumatic events. Though specific mental health treatments have been found to be efficacious and cost-effective for low-resource settings, most individuals living in these areas do not have access to them. Low-intensity task-sharing interventions will help, but there is a limit to the scalability and sustainability of human resources in these settings. To address the needs of trauma survivors, it will be important to develop and implement Internet and mobile technology resources to help reduce the scarcity, inequity, and inefficiency of current mental health services in LMICs. Mobile and Internet resources are experiencing a rapid growth in LMICs and can help address time, stigma, and cost barriers and connect those who have been socially isolated by traumatic events. This review discusses current research in technological interventions in low-resource settings and outlines key issues and future challenges and opportunities. Though formidable challenges exist for large-scale deployment of mobile and Internet mental health technologies, work to date indicates that these technologies are indeed feasible to develop, evaluate, and deliver to those in need of mental health services, and that they can be effective.
Prevalence of problematic mobile phone use in British adolescents.

PubMed

Lopez-Fernandez, Olatz; Honrubia-Serrano, Luisa; Freixa-Blanxart, Montserrat; Gibson, Will

2014-02-01

The problematic use of mobile phones among adolescents has not been widely studied. There are very few instruments for assessing potential technological addiction to mobile phones, or for categorizing different types of users or uses. The most widely used scale is the Mobile Phone Problem Use Scale (MPPUS), which is used to study adult populations, and has been applied in various forms in international contexts. The aims of this study were to adapt the Spanish version of this scale (MPPUSA) to British adolescents, and then to estimate the prevalence of possible problematic users. A questionnaire was administered to a sample of 1,529 secondary school pupils aged between 11 and 18 years, with 1,026 completed questionnaires being collected. The analysis showed that the factor and construct validity and reliability were comparable to those obtained in previous studies. The prevalence of problematic users among the students was 10%, and the typical problematic user tended to be an adolescent between 11 and 14 years old, studying in a public school, who considered themselves to be an expert user of this technology, who made extensive use of his/her mobile phone, and who attributed the same problem of use among their peers. These users presented notable scores in all the symptoms covered by the scale used to assess problematic use. In conclusion, the adaptation of the MPPUSA as a screening scale for British adolescents presents good sensitivity and specificity for detecting the main addictive symptoms proposed in this validated version.
User Centred Design and Nosocomials in Surgical ICUs: A Mobile Application for Peer Monitoring and Training in Hand Hygiene.

PubMed

Kariyawasam, Nadish; Wong, Ming Chao; Turner, Paul

2017-01-01

Nosocomial infections are a global public health risk. In low and middle-income countries the problem is acute with very high infection rates commonly contributing to poor patient outcomes including mortality. Organisational, cultural, and individual factors have been identified in these high rates, with poor hand hygiene compliance amongst clinicians a major risk factor. New approaches to achieving clinician behaviour change are required. User-centred approaches have proven effective to engage and support changes in clinician behaviours through the use of electronic tools. This paper reports on the experience of co-designing and implementing a mobile application with clinicians to enhance hand hygiene compliance. The peer monitoring and training supported by the application aims to directly contribute to evidence on reductions in infection rates in two surgical ICUs in Sri Lanka.
Timeliness of notification systems for infectious diseases: A systematic literature review.

PubMed

Swaan, Corien; van den Broek, Anouk; Kretzschmar, Mirjam; Richardus, Jan Hendrik

2018-01-01

Timely notification of infectious diseases is crucial for prompt response by public health services. Adequate notification systems facilitate timely notification. A systematic literature review was performed to assess outcomes of studies on notification timeliness and to determine which aspects of notification systems are associated with timely notification. Articles reviewing timeliness of notifications published between 2000 and 2017 were searched in Pubmed and Scopus. Using a standardized notification chain, timeliness of reporting system for each article was defined as either sufficient (≥ 80% notifications in time), partly sufficient (≥ 50-80%), or insufficient (< 50%) according to the article's predefined timeframe, a standardized timeframe for all articles, and a disease specific timeframe. Electronic notification systems were compared with conventional methods (postal mail, fax, telephone, email) and mobile phone reporting. 48 articles were identified. In almost one third of the studies with a predefined timeframe (39), timeliness of notification systems was either sufficient or insufficient (11/39, 28% and 12/39, 31% resp.). Applying the standardized timeframe (45 studies) revealed similar outcomes (13/45, 29%, sufficient notification timeframe, vs 15/45, 33%, insufficient). The disease specific timeframe was not met by any study. Systems involving reporting by laboratories most often complied sufficiently with predefined or standardized timeframes. Outcomes were not related to electronic, conventional notification systems or mobile phone reporting. Electronic systems were faster in comparative studies (10/13); this hardly resulted in sufficient timeliness, neither according to predefined nor to standardized timeframes. A minority of notification systems meets either predefined, standardized or disease specific timeframes. Systems including laboratory reporting are associated with timely notification. Electronic systems reduce reporting delay, but implementation needs considerable effort to comply with notification timeframes. During outbreak threats, patient, doctors and laboratory testing delays need to be reduced to achieve timely detection and notification. Public health authorities should incorporate procedures for this in their preparedness plans.
High-mobility BaSnO 3 grown by oxide molecular beam epitaxy

DOE PAGES

Raghavan, Santosh; Schumann, Timo; Kim, Honggyu; ...

2016-01-28

High-mobility perovskite BaSnO 3 films are of significant interest as newwide bandgap semiconductors for power electronics, transparent conductors, and as high mobility channels for epitaxial integration with functional perovskites. Despite promising results for single crystals, high-mobility BaSnO 3 films have been challenging to grow. Here, we demonstrate a modified oxide molecular beam epitaxy (MBE) approach, which supplies pre-oxidized SnO x. This technique addresses issues in the MBE of ternary stannates related to volatile SnO formation and enables growth of epitaxial, stoichiometric BaSnO 3. We demonstrate room temperature electron mobilities of 150 cm 2 V -1 s -1 in films grownmore » on PrScO 3. Lastly, the results open up a wide range of opportunities for future electronic devices.« less
75 FR 4343 - Foreign-Trade Zone 22-Chicago, IL; Application for Manufacturing Authority; LG Electronics...

Federal Register 2010, 2011, 2012, 2013, 2014

2010-01-27

... DEPARTMENT OF COMMERCE Foreign-Trade Zones Board [Docket 3-2010] Foreign-Trade Zone 22--Chicago, IL; Application for Manufacturing Authority; LG Electronics MobileComm USA, Inc. (Cell Phone Kitting... authority on behalf of LG Electronics MobileComm USA, Inc. (LGEMU), located in Bolingbrook, Illinois. The...

Electron mobility enhancement in metalorganic-vapor-phase-epitaxy-grown InAlN high-electron-mobility transistors by control of surface morphology of spacer layer

NASA Astrophysics Data System (ADS)

Yamada, Atsushi; Ishiguro, Tetsuro; Kotani, Junji; Nakamura, Norikazu

2018-01-01

We demonstrated low-sheet-resistance metalorganic-vapor-phase-epitaxy-grown InAlN high-electron-mobility transistors using AlGaN spacers with excellent surface morphology. We systematically investigated the effects of AlGaN spacer growth conditions on surface morphology and electron mobility. We found that the surface morphology of InAlN barriers depends on that of AlGaN spacers. Ga desorption from AlGaN spacers was suppressed by increasing the trimethylaluminum (TMA) supply rate, resulting in the small surface roughnesses of InAlN barriers and AlGaN spacers. Moreover, we found that an increase in the NH3 supply rate also improved the surface morphologies of InAlN barriers and AlGaN spacers as long as the TMA supply rate was high enough to suppress the degradation of GaN channels. Finally, we realized a low sheet resistance of 185.5 Ω/sq with a high electron mobility of 1210 cm2 V-1 s-1 by improving the surface morphologies of AlGaN spacers and InAlN barriers.
Indium antimonide quantum well structures for electronic device applications

NASA Astrophysics Data System (ADS)

Edirisooriya, Madhavie

The electron effective mass is smaller in InSb than in any other III-V semiconductor. Since the electron mobility depends inversely on the effective mass, InSb-based devices are attractive for field effect transistors, magnetic field sensors, ballistic transport devices, and other applications where the performance depends on a high mobility or a long mean free path. In addition, electrons in InSb have a large g-factor and strong spin orbit coupling, which makes them well suited for certain spin transport devices. The first n-channel InSb high electron mobility transistor (HEMT) was produced in 2005 with a power-delay product superior to HEMTs with a channel made from any other III-V semiconductor. The high electron mobility in the InSb quantum-well channel increases the switching speed and lowers the required supply voltage. This dissertation focuses on several materials challenges that can further increase the appeal of InSb quantum wells for transistors and other electronic device applications. First, the electron mobility in InSb quantum wells, which is the highest for any semiconductor quantum well, can be further increased by reducing scattering by crystal defects. InSb-based heteroepitaxy is usually performed on semi-insulating GaAs (001) substrates due to the lack of a lattice matched semi-insulating substrate. The 14.6% mismatch between the lattice parameters of GaAs and InSb results in the formation of structural defects such as threading dislocations and microtwins which degrade the electrical and optical properties of InSb-based devices. Chapter 1 reviews the methods and procedures for growing InSb-based heterostructures by molecular beam epitaxy. Chapters 2 and 3 introduce techniques for minimizing the crystalline defects in InSb-based structures grown on GaAs substrates. Chapter 2 discusses a method of reducing threading dislocations by incorporating AlyIn1-ySb interlayers in an AlxIn1-xSb buffer layer and the reduction of microtwin defects by growth on GaAs substrates that are oriented 2° away from the [011] direction. Chapter 3 discusses designing InSb QW layer structures that are strain balanced. By applying these defect-reducing techniques, the electron mobility in InSb quantum wells at room temperature was significantly increased. For complementary logic technology, p-channel transistors with high mobility are equally as important as n-channel transistors. However, achieving a high hole mobility in III-V semiconductors is challenging. A controlled introduction of strain in the quantum-well material is an effective technique for enhancing the hole mobility beyond its value in bulk material. The strain reduces the hole effective mass by splitting the heavy hole and light hole valence bands. Chapter 4 discusses a successful attempt to realize p-type InSb quantum well structures. The biaxial strain applied via a relaxed metamorphic buffer resulted in a significantly higher room-temperature hole mobility and a record high low-temperature hole mobility. To demonstrate the usefulness of high mobility in a device structure, magnetoresistive devices were fabricated from remotely doped InSb QWs. Such devices have numerous practical applications such as position and speed sensors and as read heads in magnetic storage systems. In a magnetoresistive device composed of a series of shorted Hall bars, the magnetoresistance is proportional to the electron mobility squared for small magnetic fields. Hence, the high electron mobility in InSb QWs makes them highly preferable for geometrical magnetoresistors. Chapter 5 reports the fabrication and characterization of InSb quantum-well magnetoresistors. The excellent transport properties of the InSb QWs resulted in high room-temperature sensitivity to applied magnetic fields. Finally, Chapter 6 provides the conclusions obtained during this research effort, and makes suggestions for future work.
THE DEPENDENCE OF ION AND ELECTRON MOBILITY UPON MOLECULAR STRUCTURE IN DIELECTRIC LIQUIDS (in German)

DOE Office of Scientific and Technical Information (OSTI.GOV)

Adamczewski, I.

1961-09-01

The viscosity coefficient of dielectric liquids was found to be dependent upon molecular structure and temperature. From this a general formula for ion and electron mobility was derived. This formula includes the dependence of mobility upon molecular structure and temperature, thus making it possible to give a theoretical explanation of other published experimental results. In addition, the formula can be used to calculate ion mobility for a number of other liquids at various temperatures. (auth)
Room-temperature mobility above 2200 cm{sup 2}/V·s of two-dimensional electron gas in a sharp-interface AlGaN/GaN heterostructure

DOE Office of Scientific and Technical Information (OSTI.GOV)

Chen, Jr-Tai, E-mail: jrche@ifm.liu.se; Persson, Ingemar; Nilsson, Daniel

A high mobility of 2250 cm{sup 2}/V·s of a two-dimensional electron gas (2DEG) in a metalorganic chemical vapor deposition-grown AlGaN/GaN heterostructure was demonstrated. The mobility enhancement was a result of better electron confinement due to a sharp AlGaN/GaN interface, as confirmed by scanning transmission electron microscopy analysis, not owing to the formation of a traditional thin AlN exclusion layer. Moreover, we found that the electron mobility in the sharp-interface heterostructures can sustain above 2000 cm{sup 2}/V·s for a wide range of 2DEG densities. Finally, it is promising that the sharp-interface AlGaN/GaN heterostructure would enable low contact resistance fabrication, less impurity-related scattering, andmore » trapping than the AlGaN/AlN/GaN heterostructure, as the high-impurity-contained AlN is removed.« less
DOE Office of Scientific and Technical Information (OSTI.GOV)

Saudari, Sangameshwar R.; Kagan, Cherie R.; Department of Electrical and Systems Engineering, University of Pennsylvania, Philadelphia, Pennsylvania 19104

Solution-processed, ambipolar, thin-film pentacene field-effect transistors were employed to study both electron and hole transport simultaneously in a single, organic solid-state device. Electron and hole mobilities were extracted from the respective unipolar saturation regimes and show thermally activated behavior and gate voltage dependence. We fit the gate voltage dependent saturation mobility to a power law to extract the characteristic Meyer-Neldel (MN) energy, a measure of the width of the exponential distribution of localized states extending into the energy gap of the organic semiconductor. The MN energy is ∼78 and ∼28 meV for electrons and holes, respectively, which reflects a greater densitymore » of localized tail states for electrons than holes. This is consistent with the lower measured electron than hole mobility. For holes, the well-behaved linear regime allows for four-point probe measurement of the contact resistance independent mobility and separate characterization of the width of the localized density of states, yielding a consistent MN energy of 28 meV.« less
A Heuristic Approach to the Theater Distribution Problem

DTIC Science & Technology

2014-03-27

outstanding guidance on this thesis research as well as the introduction to joint mobility modeling in OPER 674 which sparked my interest in this area of...32 xi List of Acronyms Acronym Definition AMP Analysis of Mobility Platform DARP Dial-A-Ride problem...tabu SMM Strategic Mobility Modeling TDD time definite delivery TDM Theater Distribution Model TDP Theater Distribution Problem TPFDD Time Phased Force
Packaging of electronic modules

NASA Technical Reports Server (NTRS)

Katzin, L.

1966-01-01

Study of design approaches that are taken toward optimizing the packaging of electronic modules with respect to size, shape, component orientation, interconnections, and structural support. The study does not present a solution to specific packaging problems, but rather the factors to be considered to achieve optimum packaging designs.
Normal-mode-based analysis of electron plasma waves with second-order Hermitian formalism

DOE Office of Scientific and Technical Information (OSTI.GOV)

Ramos, J. J.; White, R. L.

The classic problem of the dynamic evolution and Landau damping of linear Langmuir electron waves in a collisionless plasma with Maxwellian background is cast as a second-order, self-adjoint problem with a continuum spectrum of real and positive squared frequencies. The corresponding complete basis of singular normal modes is obtained, along with their orthogonality relation. This yields easily the general expression of the time-reversal-invariant solution for any initial-value problem. Examples are then given for specific initial conditions that illustrate different behaviors of the Landau-damped macroscopic moments of the perturbations.
Normal-mode-based analysis of electron plasma waves with second-order Hermitian formalism

DOE PAGES

Ramos, J. J.; White, R. L.

2018-03-01

The classic problem of the dynamic evolution and Landau damping of linear Langmuir electron waves in a collisionless plasma with Maxwellian background is cast as a second-order, self-adjoint problem with a continuum spectrum of real and positive squared frequencies. The corresponding complete basis of singular normal modes is obtained, along with their orthogonality relation. This yields easily the general expression of the time-reversal-invariant solution for any initial-value problem. Examples are then given for specific initial conditions that illustrate different behaviors of the Landau-damped macroscopic moments of the perturbations.
Localization in random bipartite graphs: Numerical and empirical study

NASA Astrophysics Data System (ADS)

Slanina, František

2017-05-01

We investigate adjacency matrices of bipartite graphs with a power-law degree distribution. Motivation for this study is twofold: first, vibrational states in granular matter and jammed sphere packings; second, graphs encoding social interaction, especially electronic commerce. We establish the position of the mobility edge and show that it strongly depends on the power in the degree distribution and on the ratio of the sizes of the two parts of the bipartite graph. At the jamming threshold, where the two parts have the same size, localization vanishes. We found that the multifractal spectrum is nontrivial in the delocalized phase, but still near the mobility edge. We also study an empirical bipartite graph, namely, the Amazon reviewer-item network. We found that in this specific graph the mobility edge disappears, and we draw a conclusion from this fact regarding earlier empirical studies of the Amazon network.
Localization in random bipartite graphs: Numerical and empirical study.

PubMed

Slanina, František

2017-05-01

We investigate adjacency matrices of bipartite graphs with a power-law degree distribution. Motivation for this study is twofold: first, vibrational states in granular matter and jammed sphere packings; second, graphs encoding social interaction, especially electronic commerce. We establish the position of the mobility edge and show that it strongly depends on the power in the degree distribution and on the ratio of the sizes of the two parts of the bipartite graph. At the jamming threshold, where the two parts have the same size, localization vanishes. We found that the multifractal spectrum is nontrivial in the delocalized phase, but still near the mobility edge. We also study an empirical bipartite graph, namely, the Amazon reviewer-item network. We found that in this specific graph the mobility edge disappears, and we draw a conclusion from this fact regarding earlier empirical studies of the Amazon network.
Anisotropic carrier mobility in single- and bi-layer C3N sheets

NASA Astrophysics Data System (ADS)

Wang, Xueyan; Li, Qingfang; Wang, Haifeng; Gao, Yan; Hou, Juan; Shao, Jianxin

2018-05-01

Based on the density functional theory combined with the Boltzmann transport equation with relaxation time approximation, we investigate the electronic structure and predict the carrier mobility of single- and bi-layer newly fabricated 2D carbon nitrides C3N. Although C3N sheets possess graphene-like planar hexagonal structure, the calculated carrier mobility is remarkably anisotropic, which is found mainly induced by the anisotropic effective masses and deformation potential constants. Importantly, we find that both the electron and hole mobilities are considerable high, for example, the hole mobility along the armchair direction of single-layer C3N sheets can arrive as high as 1.08 ×104 cm2 V-1 s-1, greatly larger than that of C2N-h2D and many other typical 2D materials. Owing to the high and anisotropic carrier mobility and appropriate band gap, single- and bi-layer semiconducting C3N sheets may have great potential applications in high performance electronic and optoelectronic devices.
Defect-mediated transport and electronic irradiation effect in individual domains of CVD-grown monolayer MoS 2

DOE PAGES

Durand, Corentin; Zhang, Xiaoguang; Fowlkes, Jason; ...

2015-01-16

We study the electrical transport properties of atomically thin individual crystalline grains of MoS 2 with four-probe scanning tunneling microscopy. The monolayer MoS 2 domains are synthesized by chemical vapor deposition on SiO 2/Si substrate. Temperature dependent measurements on conductance and mobility show that transport is dominated by an electron charge trapping and thermal release process with very low carrier density and mobility. The effects of electronic irradiation are examined by exposing the film to electron beam in the scanning electron microscope in an ultrahigh vacuum environment. The irradiation process is found to significantly affect the mobility and the carriermore » density of the material, with the conductance showing a peculiar time-dependent relaxation behavior. It is suggested that the presence of defects in active MoS 2 layer and dielectric layer create charge trapping sites, and a multiple trapping and thermal release process dictates the transport and mobility characteristics. The electron beam irradiation promotes the formation of defects and impact the electrical properties of MoS 2. Finally, our study reveals the important roles of defects and the electron beam irradiation effects in the electronic properties of atomic layers of MoS 2.« less
77 FR 11156 - Notice of Receipt of Complaint; Solicitation of Comments Relating to the Public Interest

Federal Register 2010, 2011, 2012, 2013, 2014

2012-02-24

... Certain Consumer Electronics, Including Mobile Phones and Tablets, DN 2878; the Commission is soliciting... importation of certain consumer electronics, including mobile phones and tablets. The complaint names as...
High-Efficiency Nonfullerene Polymer Solar Cell Enabling by Integration of Film-Morphology Optimization, Donor Selection, and Interfacial Engineering.

PubMed

Zhang, Xin; Li, Weiping; Yao, Jiannian; Zhan, Chuanlang

2016-06-22

Carrier mobility is a vital factor determining the electrical performance of organic solar cells. In this paper we report that a high-efficiency nonfullerene organic solar cell (NF-OSC) with a power conversion efficiency of 6.94 ± 0.27% was obtained by optimizing the hole and electron transportations via following judicious selection of polymer donor and engineering of film-morphology and cathode interlayers: (1) a combination of solvent annealing and solvent vapor annealing optimizes the film morphology and hence both hole and electron mobilities, leading to a trade-off of fill factor and short-circuit current density (Jsc); (2) the judicious selection of polymer donor affords a higher hole and electron mobility, giving a higher Jsc; and (3) engineering the cathode interlayer affords a higher electron mobility, which leads to a significant increase in electrical current generation and ultimately the power conversion efficiency (PCE).
Temperature dependence of ballistic mobility in a metamorphic InGaAs/InAlAs high electron mobility transistor

DOE Office of Scientific and Technical Information (OSTI.GOV)

Lee, Jongkyong; Gang, Suhyun; Jo, Yongcheol

We have investigated the temperature dependence of ballistic mobility in a 100 nm-long InGaAs/InAlAs metamorphic high-electron-mobility transistor designed for millimeter-wavelength RF applications. To extract the temperature dependence of quasi-ballistic mobility, our experiment involves measurements of the effective mobility in the low-bias linear region of the transistor and of the collision-dominated Hall mobility using a gated Hall bar of the same epitaxial structure. The data measured from the experiment are consistent with that of modeled ballistic mobility based on ballistic transport theory. These results advance the understanding of ballistic transport in various transistors with a nano-scale channel length that is comparable tomore » the carrier's mean free path in the channel.« less
Quantum confinement effects on electronic photomobilities at nanostructured semiconductor surfaces: Si(111) without and with adsorbed Ag clusters

NASA Astrophysics Data System (ADS)

Hembree, Robert H.; Vazhappilly, Tijo; Micha, David A.

2017-12-01

The conductivity of holes and electrons photoexcited in Si slabs is affected by the slab thickness and by adsorbates. The mobilities of those charged carriers depend on how many layers compose the slab, and this has important scientific and technical consequences for the understanding of photovoltaic materials. A previously developed general computational procedure combining density matrix and electronic band structure treatments has been applied to extensive calculations of mobilities of photoexcited electrons and holes at Si(111) nanostructured surfaces with varying slab thickness and for varying photon energies, to investigate the expected change in mobility magnitudes as the slab thickness is increased. Results have been obtained with and without adsorbed silver clusters for comparison of their optical and photovoltaic properties. Band states were generated using a modified ab initio density functional treatment with the PBE exchange and correlation density functionals and with periodic boundary conditions for large atomic supercells. An energy gap correction was applied to the unoccupied orbital energies of each band structure by running more accurate HSE hybrid functional calculations for a Si(111) slab. Photoexcited state populations for slabs with 6, 8, 10, and 12 layers were generated using a steady state reduced density matrix including dissipative effects due to energy exchange with excitons and phonons in the medium. Mobilities have been calculated from the derivatives of voltage-driven electronic energies with respect to electronic momentum, for each energy band and for the average over bands. Results show two clear trends: (a) adding Ag increases the hole photomobilities and (b) decreasing the slab thickness increases hole photomobilities. The increased hole populations in 6- and 8-layer systems and the large increase in hole mobility for these thinner slabs can be interpreted as a quantum confinement effect of hole orbitals. As the slab thickness increases to ten and twelve layers, the effect of silver adsorbates decreases leading to smaller relative enhancements to the conduction electron and hole mobilities, but the addition of the silver nanoclusters still increases the absorbance of light and the mobility of holes compared to their mobilities in the pure Si slabs.
Development of informational-communicative system, created to improve medical help for family medicine doctors.

PubMed

Smiianov, Vladyslav A; Dryha, Natalia O; Smiianova, Olha I; Obodyak, Victor K; Zudina, Tatyana O

2018-01-01

Introduction: Today mobile health`s protection service has no concrete meaning. As an research object it was called mHealth and named by Global observatory of electronic health`s protection as "Doctor and social health practice that can be supported by any mobile units (mobile phones or smartphones), units for patient`s health control, personal computers and other units of non-wired communication". An active usage of SMS in programs for patients` cure regimen keeping was quiet predictable. Mobile and electronic units only begin their development in medical sphere. Thus, to solve all health`s protection system reformation problems a special memorandum about cooperation in creating E-Health system in Ukraine was signed. The aim: Development of ICS for monitoring and non-infection ill patients` informing system optimization as a first level of medical help. Materials and methods: During research, we used systematical approach, meta-analysis, informational-analytical systems` schemes projection, expositive modeling. Developing the backend (server part of the site), we used next technologies: 1) the Apache web server; 2) programming language PHP; 3) Yii 2 PHP Framework. In the frontend developing were used the following technologies (client part of the site): 1) Bootstrap 3; 2) Vue JS Framework. Results and conclusions: Created duo-channel system "doctor-patient" and "patient-doctor" will allow usual doctors of family medicine (DFM) take the interactive dispensary cure and avoid uncontrolled illness progress. Doctor will monitor basic physical data of patient`s health and curing process. The main goal is to create automatic system to allow doctor regularly write periodical or non-periodical notifications, get patients` questioning answers and spread information between doctor and patient; that will optimize work of DFMs.
What Do Context Aware Electronic Alerts from Virtual Learning Environments Tell Us about User Time & Location?

ERIC Educational Resources Information Center

Crane, Laura; Benachour, Phillip

2013-01-01

The paper describes the analysis of user location and time stamp information automatically logged when students receive and interact with electronic updates from the University's virtual learning environment. The electronic updates are sent to students' mobile devices using RSS feeds. The mobile reception of such information can be received in…
Server-Based and Server-Less Byod Solutions to Support Electronic Learning

DTIC Science & Technology

2016-06-01

Knowledge Online NSD National Security Directive OS operating system OWA Outlook Web Access PC personal computer PED personal electronic device PDA...mobile devices, institute mobile device policies and standards, and promote the development and use of DOD mobile and web -enabled applications” (DOD...with an isolated BYOD web server, properly educated system administrators must carry out and execute the necessary, pre-defined network security

Low Temperature Photoluminescence (PL) from High Electron Mobility Transistors (HEMTs)

DTIC Science & Technology

2015-03-01

Photoluminescence Form InxAl1-xN Films Deposited by Plasma-Assisted Molecular Beam Epitaxy ,” Submitted to Applied Physics Letters, July 2014. 8 LIST OF...TECHNICAL REPORT RDMR-WD-14-55 LOW TEMPERATURE PHOTOLUMINESCENCE (PL) FROM HIGH ELECTRON MOBILITY TRANSISTORS ( HEMTS ...Mobility Transistors ( HEMTs ) 5. FUNDING NUMBERS 6. AUTHOR(S) Adam T. Roberts and Henry O. Everitt 7. PERFORMING ORGANIZATION NAME(S
A scoping review on smart mobile devices and physical strain.

PubMed

Tegtmeier, Patricia

2018-01-01

Smart mobile devices gain increasing importance at work. Integrating these smart mobile devices into the workplace creates new opportunities and challenges for occupational health and safety. Therefore the aim of the following scoping review was to identify ergonomic challenges with the use of smart mobile devices at work with respect to physical problems. A review of 36 papers based on literature including January 2016 was conducted. Biomechanical measures in the reviewed studies demonstrated i.e., head flexion angles exceeding 20° in 20 out of 26 different conditions described. Furthermore, laterally deviated wrists were frequently noted and thumb and finger flexor muscle activities generally greater than 5% MVC were reported. The reviewed literature indicated an elevated biomechanical risk, especially for the neck, the wrists and thumb. This was due to poor posture, ongoing and intermitted muscle tension, and/or repetitive movements. Papers addressing specific risks for smartphone and tablet use in different work environments are scarce. As the technology, as well as the use of smart mobile devices is rapidly changing, further research, especially for prolonged periods in the workplace is needed.
A Greedy Scanning Data Collection Strategy for Large-Scale Wireless Sensor Networks with a Mobile Sink.

PubMed

Zhu, Chuan; Zhang, Sai; Han, Guangjie; Jiang, Jinfang; Rodrigues, Joel J P C

2016-09-06

Mobile sink is widely used for data collection in wireless sensor networks. It can avoid 'hot spot' problems but energy consumption caused by multihop transmission is still inefficient in real-time application scenarios. In this paper, a greedy scanning data collection strategy (GSDCS) is proposed, and we focus on how to reduce routing energy consumption by shortening total length of routing paths. We propose that the mobile sink adjusts its trajectory dynamically according to the changes of network, instead of predetermined trajectory or random walk. Next, the mobile sink determines which area has more source nodes, then it moves toward this area. The benefit of GSDCS is that most source nodes are no longer needed to upload sensory data for long distances. Especially in event-driven application scenarios, when event area changes, the mobile sink could arrive at the new event area where most source nodes are located currently. Hence energy can be saved. Analytical and simulation results show that compared with existing work, our GSDCS has a better performance in specific application scenarios.
A Greedy Scanning Data Collection Strategy for Large-Scale Wireless Sensor Networks with a Mobile Sink

PubMed Central

Zhu, Chuan; Zhang, Sai; Han, Guangjie; Jiang, Jinfang; Rodrigues, Joel J. P. C.

2016-01-01

Mobile sink is widely used for data collection in wireless sensor networks. It can avoid ‘hot spot’ problems but energy consumption caused by multihop transmission is still inefficient in real-time application scenarios. In this paper, a greedy scanning data collection strategy (GSDCS) is proposed, and we focus on how to reduce routing energy consumption by shortening total length of routing paths. We propose that the mobile sink adjusts its trajectory dynamically according to the changes of network, instead of predetermined trajectory or random walk. Next, the mobile sink determines which area has more source nodes, then it moves toward this area. The benefit of GSDCS is that most source nodes are no longer needed to upload sensory data for long distances. Especially in event-driven application scenarios, when event area changes, the mobile sink could arrive at the new event area where most source nodes are located currently. Hence energy can be saved. Analytical and simulation results show that compared with existing work, our GSDCS has a better performance in specific application scenarios. PMID:27608022
Mobile health platform for pressure ulcer monitoring with electronic health record integration.

PubMed

Rodrigues, Joel J P C; Pedro, Luís M C C; Vardasca, Tomé; de la Torre-Díez, Isabel; Martins, Henrique M G

2013-12-01

Pressure ulcers frequently occur in patients with limited mobility, for example, people with advanced age and patients wearing casts or prostheses. Mobile information communication technologies can help implement ulcer care protocols and the monitoring of patients with high risk, thus preventing or improving these conditions. This article presents a mobile pressure ulcer monitoring platform (mULCER), which helps control a patient's ulcer status during all stages of treatment. Beside its stand-alone version, it can be integrated with electronic health record systems as mULCER synchronizes ulcer data with any electronic health record system using HL7 standards. It serves as a tool to integrate nursing care among hospital departments and institutions. mULCER was experimented with in different mobile devices such as LG Optimus One P500, Samsung Galaxy Tab, HTC Magic, Samsung Galaxy S, and Samsung Galaxy i5700, taking into account the user's experience of different screen sizes and processing characteristics.
Electrical transport, electrothermal transport, and effective electron mass in single-crystalline In2O3 films

NASA Astrophysics Data System (ADS)

Preissler, Natalie; Bierwagen, Oliver; Ramu, Ashok T.; Speck, James S.

2013-08-01

A comprehensive study of the room-temperature electrical and electrothermal transport of single-crystalline indium oxide (In2O3) and indium tin oxide (ITO) films over a wide range of electron concentrations is reported. We measured the room-temperature Hall mobility μH and Seebeck coefficient S of unintentionally doped and Sn-doped high-quality, plasma-assisted molecular-beam-epitaxy-grown In2O3 for volume Hall electron concentrations nH from 7×1016 cm-3 (unintentionally doped) to 1×1021 cm-3 (highly Sn-doped, ITO). The resulting empirical S(nH) relation can be directly used in other In2O3 samples to estimate the volume electron concentration from simple Seebeck coefficient measurements. The mobility and Seebeck coefficient were modeled by a numerical solution of the Boltzmann transport equation. Ionized impurity scattering and polar optical phonon scattering were found to be the dominant scattering mechanisms. Acoustic phonon scattering was found to be negligible. Fitting the temperature-dependent mobility above room temperature of an In2O3 film with high mobility allowed us to find the effective Debye temperature (ΘD=700 K) and number of phonon modes (NOPML=1.33) that best describe the polar optical phonon scattering. The modeling also yielded the Hall scattering factor rH as a function of electron concentration, which is not negligible (rH≈1.4) at nondegenerate electron concentrations. Fitting the Hall-scattering-factor corrected concentration-dependent Seebeck coefficient S(n) for nondegenerate samples to the numerical solution of the Boltzmann transport equation and to widely used, simplified equations allowed us to extract an effective electron mass of m*=(0.30±0.03)me (with free electron mass me). The modeled mobility and Seebeck coefficient based on polar optical phonon and ionized impurity scattering describes the experimental results very accurately up to electron concentrations of 1019 cm-3, and qualitatively explains a mobility plateau or local maximum around 1020 cm-3. Ionized impurity scattering with doubly charged donors best describes the mobility in our unintentionally doped films, consistent with oxygen vacancies as unintentional shallow donors, whereas singly charged donors best describe our Sn-doped films. Our modeling yields a (phonon-limited) maximum theoretical drift mobility and Hall mobility of μ=190 cm2/Vs and μH=270 cm2/Vs, respectively. Simplified equations for the Seebeck coefficient describe the measured values in the nondegenerate regime using a Seebeck scattering parameter of r=-0.55 (which is consistent with the determined Debye temperature), and provide an estimate of the Seebeck coefficient to lower electron concentrations. The simplified equations fail to describe the Seebeck coefficient around the Mott transition (nMott=5.5×1018 cm-3) from nondegenerate to degenerate electron concentrations, whereas the numerical modeling accurately describes this region.
Coherent Fragments: The Problem of Mobility and Genred Information

ERIC Educational Resources Information Center

Swarts, Jason

2006-01-01

Genres embody typified discursive activity that is situated in an ecology of texts, people, and tools. Within these settings, genres help writers compose recognizable information artifacts. Increasingly, however, many professions are becoming mobile, and mobile technologies (e.g., personal digital assistants [PDAs]) are creating problems of…
Research on the information security system in electrical gis system in mobile application

NASA Astrophysics Data System (ADS)

Zhou, Chao; Feng, Renjun; Jiang, Haitao; Huang, Wei; Zhu, Daohua

2017-05-01

With the rapid development of social informatization process, the demands of government, enterprise, and individuals for spatial information becomes larger. In addition, the combination of wireless network technology and spatial information technology promotes the generation and development of mobile technologies. In today’s rapidly developed information technology field, network technology and mobile communication have become the two pillar industries by leaps and bounds. They almost absorbed and adopted all the latest information, communication, computer, electronics and so on new technologies. Concomitantly, the network coverage is more and more big, the transmission rate is faster and faster, the volume of user’s terminal is smaller and smaller. What’s more, from LAN to WAN, from wired network to wireless network, from wired access to mobile wireless access, people’s demand for communication technology is increasingly higher. As a result, mobile communication technology is facing unprecedented challenges as well as unprecedented opportunities. When combined with the existing mobile communication network, it led to the development of leaps and bounds. However, due to the inherent dependence of the system on the existing computer communication network, information security problems cannot be ignored. Today’s information security has penetrated into all aspects of life. Information system is a complex computer system, and it’s physical, operational and management vulnerabilities constitute the security vulnerability of the system. Firstly, this paper analyzes the composition of mobile enterprise network and information security threat. Secondly, this paper puts forward the security planning and measures, and constructs the information security structure.
Consumer Mobile Health Apps: Current State, Barriers, and Future Directions.

PubMed

Kao, Cheng-Kai; Liebovitz, David M

2017-05-01

This paper discusses the current state, barriers, and future directions of consumer-facing applications (apps). There are currently more than 165,000 mobile health apps publicly available in major app stores, the vast majority of which are designed for patients. The top 2 categories are wellness management and disease management apps, whereas other categories include self-diagnosis, medication reminder, and electronic patient portal apps. Apps specific to physical medicine and rehabilitation also are reviewed. These apps have the potential to provide low-cost, around-the-clock access to high-quality, evidence-based health information to end users on a global scale. However, they have not yet lived up to their potential due to multiple barriers, including lack of regulatory oversight, limited evidence-based literature, and concerns of privacy and security. The future directions may consist of improving data integration into the health care system, an interoperable app platform allowing access to electronic health record data, cloud-based personal health record across health care networks, and increasing app prescription by health care providers. For consumer mobile health apps to fully contribute value to health care delivery and chronic disease management, all stakeholders within the ecosystem must collaborate to overcome the significant barriers. Copyright © 2017 American Academy of Physical Medicine and Rehabilitation. Published by Elsevier Inc. All rights reserved.
Personality and self-reported use of mobile phones for games.

PubMed

Phillips, James G; Butt, Sarah; Blaszczynski, Alex

2006-12-01

Mobile phones are popular devices that may generate problems for a section of the community. A previous study using the Eysenck Personality Questionnaire found that extraverts with low self-esteem reported more problems with their mobile phone use. The present study used the NEO FI and Coopersmith Self-Esteem Inventory to predict the self reported mobile phone use of 112 participants. Multiple regression found that people low on agreeableness were more likely to use their mobile phones to play games. The findings imply an interplay between personality traits and excessive or problematic use on mobile phones that is relevant to proposed innovations such as gambling on mobile phones.
The Effect of Technological Devices on Cervical Lordosis.

PubMed

Öğrenci, Ahmet; Koban, Orkun; Yaman, Onur; Dalbayrak, Sedat; Yılmaz, Mesut

2018-03-15

There is a need for cervical flexion and even cervical hyperflexion for the use of technological devices, especially mobile phones. We investigated the effect of this use on the cervical lordosis angle. A group of 156 patients who applied with only neck pain between 2013-2016 and had no additional problems were included. Patients are specifically questioned about mobile phone, tablet, and other devices usage. The value obtained by multiplying the year of usage and the average usage (hour) in daily life was determined as the total usage value (an average hour per day x year: hy). Cervical lordosis angles were statistically compared with the total time of use. In the general ROC analysis, the cut-off value was found to be 20.5 hy. When the cut-off value is tested, the overall accuracy is very good with 72.4%. The true estimate of true risk and non-risk is quite high. The ROC analysis is statistically significant. The use of computing devices, especially mobile telephones, and the increase in the flexion of the cervical spine indicate that cervical vertebral problems will increase even in younger people in future. Also, to using with attention at this point, ergonomic devices must also be developed.
Structured scaffolding for reflection and problem solving in diabetes self-management: qualitative study of mobile diabetes detective.

PubMed

Mamykina, Lena; Heitkemper, Elizabeth M; Smaldone, Arlene M; Kukafka, Rita; Cole-Lewis, Heather; Davidson, Patricia G; Mynatt, Elizabeth D; Tobin, Jonathan N; Cassells, Andrea; Goodman, Carrie; Hripcsak, George

2016-01-01

To investigate subjective experiences and patterns of engagement with a novel electronic tool for facilitating reflection and problem solving for individuals with type 2 diabetes, Mobile Diabetes Detective (MoDD). In this qualitative study, researchers conducted semi-structured interviews with individuals from economically disadvantaged communities and ethnic minorities who are participating in a randomized controlled trial of MoDD. The transcripts of the interviews were analyzed using inductive thematic analysis; usage logs were analyzed to determine how actively the study participants used MoDD. Fifteen participants in the MoDD randomized controlled trial were recruited for the qualitative interviews. Usage log analysis showed that, on average, during the 4 weeks of the study, the study participants logged into MoDD twice per week, reported 120 blood glucose readings, and set two behavioral goals. The qualitative interviews suggested that individuals used MoDD to follow the steps of the problem-solving process, from identifying problematic blood glucose patterns, to exploring behavioral triggers contributing to these patterns, to selecting alternative behaviors, to implementing these behaviors while monitoring for improvements in glycemic control. This qualitative study suggested that informatics interventions for reflection and problem solving can provide structured scaffolding for facilitating these processes by guiding users through the different steps of the problem-solving process and by providing them with context-sensitive evidence and practice-based knowledge related to diabetes self-management on each of those steps. This qualitative study suggested that MoDD was perceived as a useful tool in engaging individuals in self-monitoring, reflection, and problem solving. © The Author 2016. Published by Oxford University Press on behalf of the American Medical Informatics Association. All rights reserved. For Permissions, please email: journals.permissions@oup.com.
What is Bobath? A survey of UK stroke physiotherapists' perceptions of the content of the Bobath concept to treat postural control and mobility problems after stroke.

PubMed

Tyson, S F; Connell, L A; Busse, M E; Lennon, S

2009-01-01

The aim of this study was to identify which interventions used to treat postural control and mobility are considered part of the Bobath concept (BC). DESIGN. Hospital-based UK stroke physiotherapists identified interventions which they perceived to be part of the BC from a pre-published list of interventions used to treat postural control and mobility problems. Interventions that > 75% of participants felt were part of the BC were classified as 'definitely Bobath'. Interventions that < 25% felt were part of the BC were classified as 'definitely not Bobath'. Other interventions were classified as 'unsure'; those indentified by 50-74% of participants as part of the BC were classified as 'probably Bobath' and those indentified 26-49% were classified as 'probably not Bobath'. Seventy-four physiotherapists from 33 hospitals participated. Facilitation, mobilizations and practicing components of activities were most strongly associated with the BC. Exercise and the use of equipment were identified as 'not' or 'probably not Bobath'. There was uncertainty about practicing activities, teaching patients and carers and arranging independent practice. UK stroke physiotherapists perceive that the BC involves interventions that focus on facilitating movement, mobilization, practicing components of activities and some whole activities. Their views about what is not part of the BC and the areas where they are uncertain contrast with British and international teachers of the BC. Consequently, it was not possible to define a 'typical package' of treatment for postural control and mobility that represents the BC. Future research into the BC should focus on the effectiveness of specific, well-defined interventions.
A Novel Loss Recovery and Tracking Scheme for Maneuvering Target in Hybrid WSNs.

PubMed

Qian, Hanwang; Fu, Pengcheng; Li, Baoqing; Liu, Jianpo; Yuan, Xiaobing

2018-01-25

Tracking a mobile target, which aims to timely monitor the invasion of specific target, is one of the most prominent applications in wireless sensor networks (WSNs). Traditional tracking methods in WSNs only based on static sensor nodes (SNs) have several critical problems. For example, to void the loss of mobile target, many SNs must be active to track the target in all possible directions, resulting in excessive energy consumption. Additionally, when entering coverage holes in the monitoring area, the mobile target may be missing and then its state is unknown during this period. To tackle these problems, in this paper, a few mobile sensor nodes (MNs) are introduced to cooperate with SNs to form a hybrid WSN due to their stronger abilities and less constrained energy. Then, we propose a valid target tracking scheme for hybrid WSNs to dynamically schedule the MNs and SNs. Moreover, a novel loss recovery mechanism is proposed to find the lost target and recover the tracking with fewer SNs awakened. Furthermore, to improve the robustness and accuracy of the recovery mechanism, an adaptive unscented Kalman filter (AUKF) algorithm is raised to dynamically adjust the process noise covariance. Simulation results demonstrate that our tracking scheme for maneuvering target in hybrid WSNs can not only track the target effectively even if the target is lost but also maintain an excellent accuracy and robustness with fewer activated nodes.
A Novel Loss Recovery and Tracking Scheme for Maneuvering Target in Hybrid WSNs

PubMed Central

Liu, Jianpo; Yuan, Xiaobing

2018-01-01

Tracking a mobile target, which aims to timely monitor the invasion of specific target, is one of the most prominent applications in wireless sensor networks (WSNs). Traditional tracking methods in WSNs only based on static sensor nodes (SNs) have several critical problems. For example, to void the loss of mobile target, many SNs must be active to track the target in all possible directions, resulting in excessive energy consumption. Additionally, when entering coverage holes in the monitoring area, the mobile target may be missing and then its state is unknown during this period. To tackle these problems, in this paper, a few mobile sensor nodes (MNs) are introduced to cooperate with SNs to form a hybrid WSN due to their stronger abilities and less constrained energy. Then, we propose a valid target tracking scheme for hybrid WSNs to dynamically schedule the MNs and SNs. Moreover, a novel loss recovery mechanism is proposed to find the lost target and recover the tracking with fewer SNs awakened. Furthermore, to improve the robustness and accuracy of the recovery mechanism, an adaptive unscented Kalman filter (AUKF) algorithm is raised to dynamically adjust the process noise covariance. Simulation results demonstrate that our tracking scheme for maneuvering target in hybrid WSNs can not only track the target effectively even if the target is lost but also maintain an excellent accuracy and robustness with fewer activated nodes. PMID:29370103
An intelligent telecardiology system using a wearable and wireless ECG to detect atrial fibrillation.

PubMed

Lin, Chin-Teng; Chang, Kuan-Cheng; Lin, Chun-Ling; Chiang, Chia-Cheng; Lu, Shao-Wei; Chang, Shih-Sheng; Lin, Bor-Shyh; Liang, Hsin-Yueh; Chen, Ray-Jade; Lee, Yuan-Teh; Ko, Li-Wei

2010-05-01

This study presents a novel wireless, ambulatory, real-time, and autoalarm intelligent telecardiology system to improve healthcare for cardiovascular disease, which is one of the most prevalent and costly health problems in the world. This system consists of a lightweight and power-saving wireless ECG device equipped with a built-in automatic warning expert system. This device is connected to a mobile and ubiquitous real-time display platform. The acquired ECG signals are instantaneously transmitted to mobile devices, such as netbooks or mobile phones through Bluetooth, and then, processed by the expert system. An alert signal is sent to the remote database server, which can be accessed by an Internet browser, once an abnormal ECG is detected. The current version of the expert system can identify five types of abnormal cardiac rhythms in real-time, including sinus tachycardia, sinus bradycardia, wide QRS complex, atrial fibrillation (AF), and cardiac asystole, which is very important for both the subjects who are being monitored and the healthcare personnel tracking cardiac-rhythm disorders. The proposed system also activates an emergency medical alarm system when problems occur. Clinical testing reveals that the proposed system is approximately 94% accurate, with high sensitivity, specificity, and positive prediction rates for ten normal subjects and 20 AF patients. We believe that in the future a business-card-like ECG device, accompanied with a mobile phone, can make universal cardiac protection service possible.
Housing Mobility and Cognitive Development: Change in Verbal and Nonverbal Abilities

PubMed Central

Fowler, Patrick J.; McGrath, Lauren M.; Henry, David B.; Schoeny, Michael; Chavira, Dina; Taylor, Jeremy J.; Day, Orin

2015-01-01

This study investigates the influence of housing instability on verbal and nonverbal cognitive development among at-risk children and adolescents involved in the child welfare system. Frequent residential changes threaten child mental health, especially among low-income families. Little is known regarding disruptions to cognitive growth, specifically the impact on verbal and nonverbal abilities. The study tests whether developmental timing of housing mobility affects cognitive development beyond individual and family risks. A nationally representative study of families (n = 2,442) susceptible to housing and family instability tracked children and adolescents aged four to 14 years (M = 8.95 years) over 36 months following investigation by the child welfare system. Youth completed standardized cognitive assessments while caregivers reported on behavior problems and family risk at three time points. Latent growth models examined change in cognitive abilities over time. Housing mobility in the 12 months prior to baseline predicts lower verbal cognitive abilities that improve marginally. Similar effects emerge for all age groups; however, frequent moves in infancy diminish the influence of subsequent housing mobility on verbal tasks. Housing instability threatened cognitive development beyond child maltreatment, family changes, poverty, and other risks. Findings inform emerging research on environmental influences on neurocognitive development, as well as identify targets for early intervention. Systematic assessment of family housing problems, including through the child welfare system, provides opportunities for coordinated responses to prevent instability and cognitive threats. PMID:26184055
Addiction-Like Mobile Phone Behavior – Validation and Association With Problem Gambling

PubMed Central

Fransson, Andreas; Chóliz, Mariano; Håkansson, Anders

2018-01-01

Mobile phone use and its potential addiction has become a point of interest within the research community. The aim of the study was to translate and validate the Test of Mobile Dependence (TMD), and to investigate if there are any associations between mobile phone use and problem gambling. This was a cross-sectional study on a Swedish general population. A questionnaire consisting of a translated version of the TMD, three problem gambling questions (NODS-CLiP) together with two questions concerning previous addiction treatment was published online. Exploratory factor analysis based on polychoric correlations was performed on the TMD. Independent samples T-tests, Mann-Whitney test, logistic regression analyses and ANOVA were performed to examine mean differences between subjects based on TMD test score, gambling and previous addiction treatment. A total of 1,515 people (38.3% men) answered the questionnaire. The TMD showed acceptable internal consistency (Cronbach's alpha: 0.905), and significant correlation with subjective dependence on one's mobile phone. Women scored higher on the TMD and 15-18 year olds had the highest mean test score. The TMD test score was significantly associated with problem gambling, but only when controlling for age and sex. Various separated items related to mobile phone use were associated with problem gambling. The TMD had acceptable internal consistency and correlates with subjective dependence, while future confirmatory factor analysis is recommended. An association between mobile phone use and problem gambling may be possible, but requires further research. PMID:29780345
Addiction-Like Mobile Phone Behavior - Validation and Association With Problem Gambling.

PubMed

Fransson, Andreas; Chóliz, Mariano; Håkansson, Anders

2018-01-01

Mobile phone use and its potential addiction has become a point of interest within the research community. The aim of the study was to translate and validate the Test of Mobile Dependence (TMD), and to investigate if there are any associations between mobile phone use and problem gambling. This was a cross-sectional study on a Swedish general population. A questionnaire consisting of a translated version of the TMD, three problem gambling questions (NODS-CLiP) together with two questions concerning previous addiction treatment was published online. Exploratory factor analysis based on polychoric correlations was performed on the TMD. Independent samples T -tests, Mann-Whitney test, logistic regression analyses and ANOVA were performed to examine mean differences between subjects based on TMD test score, gambling and previous addiction treatment. A total of 1,515 people (38.3% men) answered the questionnaire. The TMD showed acceptable internal consistency (Cronbach's alpha: 0.905), and significant correlation with subjective dependence on one's mobile phone. Women scored higher on the TMD and 15-18 year olds had the highest mean test score. The TMD test score was significantly associated with problem gambling, but only when controlling for age and sex. Various separated items related to mobile phone use were associated with problem gambling. The TMD had acceptable internal consistency and correlates with subjective dependence, while future confirmatory factor analysis is recommended. An association between mobile phone use and problem gambling may be possible, but requires further research.
Ion mobility analyzer - quadrupole mass spectrometer system design

NASA Astrophysics Data System (ADS)

Cuna, C.; Leuca, M.; Lupsa, N.; Mirel, V.; Bocos-Bintintan, V.; Cuna, Stela; Cosma, V.; Tusa, Florina

2009-08-01

Because of their extremely high sensitivity for chemicals with elevated electronegativity or high proton affinity the ion mobility analysers are ideal for the ultra-trace detection of toxic or explosive chemicals, most of these situated often at concentration levels of sub-ppb (parts-per-billion). Ion mobility spectrometers (IMS) can be used to identify illicit drugs or environmental pollutants. Since resolution of an IMS is relatively low, to achieve an accurate identification of target analyte it is recommended to couple the IMS with a quadrupole mass spectrometer (QMS) or a time of flight mass spectrometer, acquiring in this way confirmatory information. This coupling is made through a specific interface. In this paper, an experimental model of such a tandem instrument, IMS-QMS is described. Accomplishment of this general purpose will be done, overcoming a series of specific issues. This implies the solving, using innovative solutions, of a series of complex issues: ensuring the stability of the ions beam generated by ion source; transfer with a good efficiency of the ionic current from IMS analyser to QMS; and realization of a special electronic circuitry which will be able to detect both positive and negative ions.

Daily Rhythms in Mobile Telephone Communication

PubMed Central

Aledavood, Talayeh; López, Eduardo; Roberts, Sam G. B.; Reed-Tsochas, Felix; Moro, Esteban; Dunbar, Robin I. M.; Saramäki, Jari

2015-01-01

Circadian rhythms are known to be important drivers of human activity and the recent availability of electronic records of human behaviour has provided fine-grained data of temporal patterns of activity on a large scale. Further, questionnaire studies have identified important individual differences in circadian rhythms, with people broadly categorised into morning-like or evening-like individuals. However, little is known about the social aspects of these circadian rhythms, or how they vary across individuals. In this study we use a unique 18-month dataset that combines mobile phone calls and questionnaire data to examine individual differences in the daily rhythms of mobile phone activity. We demonstrate clear individual differences in daily patterns of phone calls, and show that these individual differences are persistent despite a high degree of turnover in the individuals’ social networks. Further, women’s calls were longer than men’s calls, especially during the evening and at night, and these calls were typically focused on a small number of emotionally intense relationships. These results demonstrate that individual differences in circadian rhythms are not just related to broad patterns of morningness and eveningness, but have a strong social component, in directing phone calls to specific individuals at specific times of day. PMID:26390215
Daily Rhythms in Mobile Telephone Communication.

PubMed

Aledavood, Talayeh; López, Eduardo; Roberts, Sam G B; Reed-Tsochas, Felix; Moro, Esteban; Dunbar, Robin I M; Saramäki, Jari

2015-01-01

Circadian rhythms are known to be important drivers of human activity and the recent availability of electronic records of human behaviour has provided fine-grained data of temporal patterns of activity on a large scale. Further, questionnaire studies have identified important individual differences in circadian rhythms, with people broadly categorised into morning-like or evening-like individuals. However, little is known about the social aspects of these circadian rhythms, or how they vary across individuals. In this study we use a unique 18-month dataset that combines mobile phone calls and questionnaire data to examine individual differences in the daily rhythms of mobile phone activity. We demonstrate clear individual differences in daily patterns of phone calls, and show that these individual differences are persistent despite a high degree of turnover in the individuals' social networks. Further, women's calls were longer than men's calls, especially during the evening and at night, and these calls were typically focused on a small number of emotionally intense relationships. These results demonstrate that individual differences in circadian rhythms are not just related to broad patterns of morningness and eveningness, but have a strong social component, in directing phone calls to specific individuals at specific times of day.
Physiotherapy to improve physical activity in community-dwelling older adults with mobility problems (Coach2Move): study protocol for a randomized controlled trial.

PubMed

de Vries, Nienke M; Staal, J Bart; Teerenstra, Steven; Adang, Eddy M M; Rikkert, Marcel G M Olde; Nijhuis-van der Sanden, Maria W G

2013-12-17

Older adults can benefit from physical activity in numerous ways. Physical activity is considered to be one of the few ways to influence the level of frailty. Standardized exercise programs do not necessarily lead to more physical activity in daily life, however, and a more personalized approach seems appropriate. The main objective of this study is to investigate whether a focused, problem-oriented coaching intervention ('Coach2Move') delivered by a physiotherapist specializing in geriatrics is more effective for improving physical activity, mobility and health status in community-dwelling older adults than usual physiotherapy care. In addition, cost-effectiveness will be determined. The design of this study is a single-blind randomized controlled trial in thirteen physiotherapy practices. Randomization will take place at the individual patient level. The study population consists of older adults, ≥70 years of age, with decreased physical functioning and mobility and/or a physically inactive lifestyle. The intervention group will receive geriatric physiotherapy according to the Coach2Move strategy. The control group will receive the usual physiotherapy care. Measurements will be performed by research assistants not aware of group assignment. The results will be evaluated on the amount of physical activity (LASA Physical Activity Questionnaire), mobility (modified 'get up and go' test, walking speed and six-minute walking test), quality of life (SF-36), degree of frailty (Evaluative Frailty Index for Physical Activity), fatigue (NRS-fatigue), perceived effect (Global Perceived Effect and Patient Specific Complaints questionnaire) and health care costs. Most studies on the effect of exercise or physical activity consist of standardized programs. In this study, a personalized approach is evaluated within a group of frail older adults, many of whom suffer from multiple and complex diseases and problems. A complicating factor in evaluating a new approach is that it may not be automatically adopted by clinicians. Specific actions are undertaken to optimize implementation of the Coach2Move strategy during the trial. Whether or not these will be sufficient is a matter we will consider subsequently, using quality indicators and process analysis. The Netherlands National Trial Register: NTR3527.
Designed to deter. Community barriers to physical activity for people with visual or motor impairments.

PubMed

Kirchner, Corinne E; Gerber, Elaine G; Smith, Brooke C

2008-04-01

People with disabilities are more likely to be obese, in poor health, and get less physical activity than the general population. However, research on community factors for physical activity has generally either excluded most people with disabilities, or overlooked relevant factors of community accessibility. This exploratory study investigated environmental factors affecting people with motor impairments and people with visual impairments in urban neighborhoods. Quantitative and qualitative methods were used with a nonrandom sample (n=134) of users of four types of assistive mobility technologies: guide dogs, long canes, and motorized and manual wheelchairs. From July 2005 to August 2006, the sample participated in two telephone surveys. Between the surveys, a stratified random subsample (n =32) engaged in an ethnographic phase of observation and interviews. Most participants in all groups using assistive mobility technologies rated their neighborhoods as accessible, although they also reported many specific barriers. Users of assistive mobility technologies differed in the amount of reported physical activity and on specific barriers. Problems with sidewalk pavement and puddles/poor drainage were the most frequently mentioned environmental barriers, by 90% and 80%, respectively. Users of assistive mobility technologies were more similar on main strategies for dealing with barriers. All groups reported having to plan routes for outings, to alter planned routes, to go more slowly than planned, or to wait for a different time. Despite legislative requirements for accommodation, people with disabilities face barriers to physical activity, both in the built and social environments. Determined people with disabilities were able to overcome barriers, but required additional expenditure of resources to do so. Community design that can include people with disabilities requires detailed understanding of barriers specific both to types of impairments and to different types of assistive mobility technologies.
Embodied Computation: An Active-Learning Approach to Mobile Robotics Education

ERIC Educational Resources Information Center

Riek, L. D.

2013-01-01

This paper describes a newly designed upper-level undergraduate and graduate course, Autonomous Mobile Robots. The course employs active, cooperative, problem-based learning and is grounded in the fundamental computational problems in mobile robotics defined by Dudek and Jenkin. Students receive a broad survey of robotics through lectures, weekly…
Charge carrier transport and photogeneration in P3HT:PCBM photovoltaic blends.

PubMed

Laquai, Frédéric; Andrienko, Denis; Mauer, Ralf; Blom, Paul W M

2015-06-01

This article reviews the charge transport and photogeneration in bulk-heterojunction solar cells made from blend films of regioregular poly(3-hexylthiophene) (RR-P3HT) and methano-fullerene (PCBM). The charge transport, specifically the hole mobility in the RR-P3HT phase of the polymer:fullerene photovoltaic blend, is dramatically affected by thermal annealing. The hole mobility increases more than three orders of magnitude and reaches a value of up to 2 × 10(-4) cm(2) V(-1) s(-1) after the thermal annealing process as a result of an improved semi-crystallinity of the film. This significant increase of the hole mobility balances the electron and hole mobilities in a photovoltaic blend in turn reducing space-charge formation, and this is the most important factor for the strong enhancement of the photovoltaic efficiency compared to an as cast, that is, non-annealed device. In fact, the balanced charge carrier mobility in RR-P3HT:PCBM blends in combination with a field- and temperature-independent charge carrier generation and greatly reduced non-geminate recombination explains the large quantum efficiencies mea-sured in P3HT:PCBM photovoltaic devices. © 2015 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.
Direct measurement of cyclotron coherence times of high-mobility two-dimensional electron gases.

PubMed

Wang, X; Hilton, D J; Reno, J L; Mittleman, D M; Kono, J

2010-06-07

We have observed long-lived (approximately 30 ps) coherent oscillations of charge carriers due to cyclotron resonance (CR) in high-mobility two-dimensional electrons in GaAs in perpendicular magnetic fields using time-domain terahertz spectroscopy. The observed coherent oscillations were fitted well by sinusoids with exponentially-decaying amplitudes, through which we were able to provide direct and precise measures for the decay times and oscillation frequencies simultaneously. This method thus overcomes the CR saturation effect, which is known to prevent determination of true CR linewidths in high-mobility electron systems using Fourier-transform infrared spectroscopy.
Two-dimensional superconductivity induced by high-mobility carrier doping in LaTiO3/SrTiO3 hetero-structures

NASA Astrophysics Data System (ADS)

Biscaras, Johan; Hurand, S.; Palma, C.; Lesueur, J.; Bergeal, N.; Leboeuf, D.; Proust, C.; Rastogi, A.; Budhani, R. C.

2013-03-01

Transition metal oxides display a great variety of quantum electronic behaviors where correlations often play an important role. The achievement of high quality epitaxial interfaces involving such materials gives a unique opportunity to engineer artificial materials where new electronic orders take place. It has been shown recently that a two-dimensional electron gas 2DEG could form at the interface of two insulators such as LaAlO3 and SrTiO3, or LaTiO3 (a Mott insulator) and SrTiO3. We show that a superconducting two-dimensional electron gas is formed at the LaTiO3/SrTiO3 interface whose properties can be modulated by field effect using a metallic gate on the back of the substrate. The gas consists of two types of carriers : a majority of low-mobility carriers always present, and a few high-mobility ones that can be injected by electrostatic doping. The calculation of the electrons spatial distribution in the confinement potential shows that the high-mobility electrons responsible for superconductivity set at the edge of the gas whose extension can be tuned by field effect.
Mobile Health Technology Using a Wearable Sensorband for Female College Students With Problem Drinking: An Acceptability and Feasibility Study.

PubMed

Leonard, Noelle Regina; Silverman, Michelle; Sherpa, Dawa Phuti; Naegle, Madeline A; Kim, Hyorim; Coffman, Donna L; Ferdschneider, Marcy

2017-07-07

An increasing number of mobile app interventions have been developed for problem drinking among college students; however, few studies have examined the integration of a mobile app with continuous physiological monitoring and alerting of affective states related to drinking behaviors. The aim of this paper was to evaluate the acceptability and feasibility of Mind the Moment (MtM), a theoretically based intervention for female college students with problem drinking that combines brief, in-person counseling with ecological momentary intervention (EMI) on a mobile app integrated with a wearable sensorband. We recruited 10 non-treatment seeking, female undergraduates from a university health clinic who scored a 3 or higher on the Alcohol Use Disorders Identification Test-Consumption (AUDIT-C) to participate in this pilot study. Study activities involved an in-person baseline intake and 1 follow-up assessment, 2 in-person alcohol brief intervention counseling sessions, and use of MtM technology components (sensorband and EMI on a mobile app) for approximately 3-4 weeks. The intervention used motivational interviewing (MI) and cognitive behavioral therapy (CBT) strategies for reducing risks associated with drinking. We used both qualitative and quantitative assessments to measure acceptability of the intervention and feasibility of delivery. Use patterns of the sensorband and mobile app were also collected. Quantitative and qualitative data indicated high levels of acceptability for the MtM intervention. Altogether, participants made reports on the app on 26.7% (78/292) the days the technology was available to them and completed a total of 325 reports with wide variation between participants. Qualitative findings indicated that sensorband-elicited alerts promoted an increase in awareness of thoughts, feelings, and behaviors related to current environmental stressors and drinking behaviors in theoretically meaningful ways. Specific challenges related to functionality and form of the sensorband were identified. Delivering intervention material "just-in-time," at the moment participants need to use behavioral strategies has great potential to individualize behavioral interventions for reducing problem drinking and other health behaviors. These findings provide initial evidence for the promise of wearable sensors for increasing potency of theoretically grounded mobile health interventions and point to directions for future research and uptake of these technologies. ©Noelle Regina Leonard, Michelle Silverman, Dawa Phuti Sherpa, Madeline A Naegle, Hyorim Kim, Donna L Coffman, Marcy Ferdschneider. Originally published in JMIR Mhealth and Uhealth (http://mhealth.jmir.org), 07.07.2017.
Electron-acoustic phonon coupling in single crystal CH3NH3PbI3 perovskites revealed by coherent acoustic phonons

NASA Astrophysics Data System (ADS)

Mante, Pierre-Adrien; Stoumpos, Constantinos C.; Kanatzidis, Mercouri G.; Yartsev, Arkady

2017-02-01

Despite the great amount of attention CH3NH3PbI3 has received for its solar cell application, intrinsic properties of this material are still largely unknown. Mobility of charges is a quintessential property in this aspect; however, there is still no clear understanding of electron transport, as reported values span over three orders of magnitude. Here we develop a method to measure the electron and hole deformation potentials using coherent acoustic phonons generated by femtosecond laser pulses. We apply this method to characterize a CH3NH3PbI3 single crystal. We measure the acoustic phonon properties and characterize electron-acoustic phonon scattering. Then, using the deformation potential theory, we calculate the carrier intrinsic mobility and compare it to the reported experimental and theoretical values. Our results reveal high electron and hole mobilities of 2,800 and 9,400 cm2 V-1 s-1, respectively. Comparison with literature values of mobility demonstrates the potential role played by polarons in charge transport in CH3NH3PbI3.
Implementation of fast handover for proxy mobile IPv6: Resolving out-of-order packets

PubMed Central

Anh, Khuong Quoc; Choo, Hyunseung

2017-01-01

Mobile IP allows for location-independent routing of IP datagrams on the Internet. Mobile IP specifies how a mobile node (MN) registers with its home agent and how the home agent routes datagrams to the MN through the tunnel. Current Mobile IP protocols have difficulties meeting the stringent handover delay requirements of future wireless networks. Fast handover for Proxy Mobile IPv6 (FPMIPv6) is used to resolve handover latency and packet loss problems that occur in the Proxy Mobile IPv6 (PMIPv6) protocol. However, while implementing the FPMIPv6 scheme in a testbed, we encounter the out-of-order packet (OoOP) problem. The cause of this problem is the existence of two paths for data transmitted from a correspondent node (CN) to an MN. Since the problem affects the quality of service (QoS) of the network and the performance of the MN, we propose a new scheme using the last packet marker and packet buffering to solve this problem in FPMIPv6. The new Mobile Access Gateway (MAG) can control and deliver the data transmitted via the old path or the new path to an MN in order, using the last packet marker to notify the end of the data delivery in the old path and the packet buffering for holding the data delivered in the new path. We implement both the proposed scheme and FPMIPv6 in a testbed as a real network environment to demonstrate the correctness, cost effectiveness, and performance of the proposed scheme. A performance evaluation reveals that the proposed scheme can handle the OoOP problem efficiently. PMID:28968450
Implementation of fast handover for proxy mobile IPv6: Resolving out-of-order packets.

PubMed

Kang, Byungseok; Anh, Khuong Quoc; Choo, Hyunseung

2017-01-01

Mobile IP allows for location-independent routing of IP datagrams on the Internet. Mobile IP specifies how a mobile node (MN) registers with its home agent and how the home agent routes datagrams to the MN through the tunnel. Current Mobile IP protocols have difficulties meeting the stringent handover delay requirements of future wireless networks. Fast handover for Proxy Mobile IPv6 (FPMIPv6) is used to resolve handover latency and packet loss problems that occur in the Proxy Mobile IPv6 (PMIPv6) protocol. However, while implementing the FPMIPv6 scheme in a testbed, we encounter the out-of-order packet (OoOP) problem. The cause of this problem is the existence of two paths for data transmitted from a correspondent node (CN) to an MN. Since the problem affects the quality of service (QoS) of the network and the performance of the MN, we propose a new scheme using the last packet marker and packet buffering to solve this problem in FPMIPv6. The new Mobile Access Gateway (MAG) can control and deliver the data transmitted via the old path or the new path to an MN in order, using the last packet marker to notify the end of the data delivery in the old path and the packet buffering for holding the data delivered in the new path. We implement both the proposed scheme and FPMIPv6 in a testbed as a real network environment to demonstrate the correctness, cost effectiveness, and performance of the proposed scheme. A performance evaluation reveals that the proposed scheme can handle the OoOP problem efficiently.
Planar-integrated single-crystalline perovskite photodetectors

PubMed Central

Saidaminov, Makhsud I.; Adinolfi, Valerio; Comin, Riccardo; Abdelhady, Ahmed L.; Peng, Wei; Dursun, Ibrahim; Yuan, Mingjian; Hoogland, Sjoerd; Sargent, Edward H.; Bakr, Osman M.

2015-01-01

Hybrid perovskites are promising semiconductors for optoelectronic applications. However, they suffer from morphological disorder that limits their optoelectronic properties and, ultimately, device performance. Recently, perovskite single crystals have been shown to overcome this problem and exhibit impressive improvements: low trap density, low intrinsic carrier concentration, high mobility, and long diffusion length that outperform perovskite-based thin films. These characteristics make the material ideal for realizing photodetection that is simultaneously fast and sensitive; unfortunately, these macroscopic single crystals cannot be grown on a planar substrate, curtailing their potential for optoelectronic integration. Here we produce large-area planar-integrated films made up of large perovskite single crystals. These crystalline films exhibit mobility and diffusion length comparable with those of single crystals. Using this technique, we produced a high-performance light detector showing high gain (above 104 electrons per photon) and high gain-bandwidth product (above 108 Hz) relative to other perovskite-based optical sensors. PMID:26548941
Evaluation of electron mobility in InSb quantum wells by means of percentage-impact

DOE Office of Scientific and Technical Information (OSTI.GOV)

Mishima, T. D.; Edirisooriya, M.; Santos, M. B.

2014-05-15

In order to quantitatively analyze the contribution of each scattering factor toward the total carrier mobility, we use a new convenient figure-of-merit, named a percentage impact. The mobility limit due to a scattering factor, which is widely used to summarize a scattering analysis, has its own advantage. However, a mobility limit is not quite appropriate for the above purpose. A comprehensive understanding of the difference in contribution among many scattering factors toward the total carrier mobility can be obtained by evaluating percentage impacts of scattering factors, which can be straightforwardly calculated from their mobility limits and the total mobility. Ourmore » percentage impact analysis shows that threading dislocation is one of the dominant scattering factors for the electron transport in InSb quantum wells at room temperature.« less
Interface-Dependent Effective Mobility in Graphene Field-Effect Transistors

NASA Astrophysics Data System (ADS)

Ahlberg, Patrik; Hinnemo, Malkolm; Zhang, Shi-Li; Olsson, Jörgen

2018-03-01

By pretreating the substrate of a graphene field-effect transistor (G-FET), a stable unipolar transfer characteristic, instead of the typical V-shape ambipolar behavior, has been demonstrated. This behavior is achieved through functionalization of the SiO2/Si substrate that changes the SiO2 surface from hydrophilic to hydrophobic, in combination with postdeposition of an Al2O3 film by atomic layer deposition (ALD). Consequently, the back-gated G-FET is found to have increased apparent hole mobility and suppressed apparent electron mobility. Furthermore, with addition of a top-gate electrode, the G-FET is in a double-gate configuration with independent top- or back-gate control. The observed difference in mobility is shown to also be dependent on the top-gate bias, with more pronounced effect at higher electric field. Thus, the combination of top and bottom gates allows control of the G-FET's electron and hole mobilities, i.e., of the transfer behavior. Based on these observations, it is proposed that polar ligands are introduced during the ALD step and, depending on their polarization, result in an apparent increase of the effective hole mobility and an apparent suppressed effective electron mobility.
Research the mobile phone operation interfaces for vision-impairment.

PubMed

Yao, Yen-Ting; Leung, Cherng-Yee

2012-01-01

Due to the vision-impaired users commonly having difficulty with mobile-phone function operations and adaption any manufacturer's user interface design, the goals for this research are established for evaluating how to improve for them the function operation convenience and user interfaces of either mobile phones or electronic appliances in the market currently. After applying collecting back 30 effective questionnaires from 30 vision-impairment, the comments have been concluded from this research include: (1) All mobile phone manufactures commonly ignorant of the vision-impairment difficulty with operating mobile phone user interfaces; (2) The vision-impairment preferential with audio alert signals; (3) The vision-impairment incapable of mobile-phone procurement independently unless with assistance from others; (4) Preferential with adding touch-usage interface design by the vision-impairment; in contrast with the least requirement for such functions as braille, enlarging keystroke size and diversifying-function control panel. With exploring the vision-impairment's necessary improvements and obstacles for mobile phone interface operation, this research is established with goals for offering reference possibly applied in electronic appliance design and . Hopefully, the analysis results of this research could be used as data references for designing electronic and high-tech products and promoting more usage convenience for those vision-impaired.
A Challenging Issue in the Etiology of Speech Problems: The Effect of Maternal Exposure to Electromagnetic Fields on Speech Problems in the Offspring

PubMed Central

Zarei, S.; Mortazavi, S. M. J.; Mehdizadeh, A. R.; Jalalipour, M.; Borzou, S.; Taeb, S.; Haghani, M.; Mortazavi, S. A. R.; Shojaei-fard, M. B.; Nematollahi, S.; Alighanbari, N.; Jarideh, S.

2015-01-01

Background Nowadays, mothers are continuously exposed to different sources of electromagnetic fields before and even during pregnancy. It has recently been shown that exposure to mobile phone radiation during pregnancy may lead to adverse effects on the brain development in offspring and cause hyperactivity. Researchers have shown that behavioral problems in laboratory animals which have a similar appearance to ADHD are caused by intrauterine exposure to mobile phones. Objective The purpose of this study was to investigate whether the maternal exposure to different sources of electromagnetic fields affect on the rate and severity of speech problems in their offspring. Methods In this study, mothers of 35 healthy 3-5 year old children (control group) and 77 children and diagnosed with speech problems who had been referred to a speech treatment center in Shiraz, Iran were interviewed. These mothers were asked whether they had exposure to different sources of electromagnetic fields such as mobile phones, mobile base stations, Wi-Fi, cordless phones, laptops and power lines. Results We found a significant association between either the call time (P=0.002) or history of mobile phone use (months used) and speech problems in the offspring (P=0.003). However, other exposures had no effect on the occurrence of speech problems. To the best of our knowledge, this is the first study to investigate a possible association between maternal exposure to electromagnetic field and speech problems in the offspring. Although a major limitation in our study is the relatively small sample size, this study indicates that the maternal exposure to common sources of electromagnetic fields such as mobile phones can affect the occurrence of speech problems in the offspring. PMID:26396971
A Challenging Issue in the Etiology of Speech Problems: The Effect of Maternal Exposure to Electromagnetic Fields on Speech Problems in the Offspring.

PubMed

Zarei, S; Mortazavi, S M J; Mehdizadeh, A R; Jalalipour, M; Borzou, S; Taeb, S; Haghani, M; Mortazavi, S A R; Shojaei-Fard, M B; Nematollahi, S; Alighanbari, N; Jarideh, S

2015-09-01

Nowadays, mothers are continuously exposed to different sources of electromagnetic fields before and even during pregnancy. It has recently been shown that exposure to mobile phone radiation during pregnancy may lead to adverse effects on the brain development in offspring and cause hyperactivity. Researchers have shown that behavioral problems in laboratory animals which have a similar appearance to ADHD are caused by intrauterine exposure to mobile phones. The purpose of this study was to investigate whether the maternal exposure to different sources of electromagnetic fields affect on the rate and severity of speech problems in their offspring. In this study, mothers of 35 healthy 3-5 year old children (control group) and 77 children and diagnosed with speech problems who had been referred to a speech treatment center in Shiraz, Iran were interviewed. These mothers were asked whether they had exposure to different sources of electromagnetic fields such as mobile phones, mobile base stations, Wi-Fi, cordless phones, laptops and power lines. We found a significant association between either the call time (P=0.002) or history of mobile phone use (months used) and speech problems in the offspring (P=0.003). However, other exposures had no effect on the occurrence of speech problems. To the best of our knowledge, this is the first study to investigate a possible association between maternal exposure to electromagnetic field and speech problems in the offspring. Although a major limitation in our study is the relatively small sample size, this study indicates that the maternal exposure to common sources of electromagnetic fields such as mobile phones can affect the occurrence of speech problems in the offspring.
From human behavior to the spread of mobile phone viruses

NASA Astrophysics Data System (ADS)

Wang, Pu

Percolation theory was initiated some 50 years ago as a mathematical framework for the study of random physical processes such as the flow of a fluid through a disordered porous medium. It has been proved to be a remarkably rich theory, with applications from thermodynamic phase transitions to complex networks. In this dissertation percolation theory is used to study the diffusion process of mobile phone viruses. Some methodologies widely used in statistical physics are also applied to uncover the underlying statistical laws of human behavior and simulate the spread of mobile phone viruses in a large population. I find that while Bluetooth viruses can reach all susceptible handsets with time, they spread slowly due to human mobility, offering ample opportunities to deploy antiviral software. In contrast, viruses utilizing multimedia messaging services (MMS) could infect all users in hours, but currently a phase transition on the underlying call graph limits them to only a small fraction of the susceptible users. These results explain the lack of a major mobile virus breakout so far and predict that once a mobile operating system's market share reaches the phase transition point, viruses will pose a serious threat to mobile communications. These studies show how the large datasets and tools of statistical physics can be used to study some specific and important problems, such as the spread of mobile phone viruses.
Exploiting node mobility for energy optimization in wireless sensor networks

NASA Astrophysics Data System (ADS)

El-Moukaddem, Fatme Mohammad

Wireless Sensor Networks (WSNs) have become increasingly available for data-intensive applications such as micro-climate monitoring, precision agriculture, and audio/video surveillance. A key challenge faced by data-intensive WSNs is to transmit the sheer amount of data generated within an application's lifetime to the base station despite the fact that sensor nodes have limited power supplies such as batteries or small solar panels. The availability of numerous low-cost robotic units (e.g. Robomote and Khepera) has made it possible to construct sensor networks consisting of mobile sensor nodes. It has been shown that the controlled mobility offered by mobile sensors can be exploited to improve the energy efficiency of a network. In this thesis, we propose schemes that use mobile sensor nodes to reduce the energy consumption of data-intensive WSNs. Our approaches differ from previous work in two main aspects. First, our approaches do not require complex motion planning of mobile nodes, and hence can be implemented on a number of low-cost mobile sensor platforms. Second, we integrate the energy consumption due to both mobility and wireless communications into a holistic optimization framework. We consider three problems arising from the limited energy in the sensor nodes. In the first problem, the network consists of mostly static nodes and contains only a few mobile nodes. In the second and third problems, we assume essentially that all nodes in the WSN are mobile. We first study a new problem called max-data mobile relay configuration (MMRC ) that finds the positions of a set of mobile sensors, referred to as relays, that maximize the total amount of data gathered by the network during its lifetime. We show that the MMRC problem is surprisingly complex even for a trivial network topology due to the joint consideration of the energy consumption of both wireless communication and mechanical locomotion. We present optimal MMRC algorithms and practical distributed implementations for several important network topologies and applications. Second, we consider the problem of minimizing the total energy consumption of a network. We design an iterative algorithm that improves a given configuration by relocating nodes to new positions. We show that this algorithm converges to the optimal configuration for the given transmission routes. Moreover, we propose an efficient distributed implementation that does not require explicit synchronization. Finally, we consider the problem of maximizing the lifetime of the network. We propose an approach that exploits the mobility of the nodes to balance the energy consumption throughout the network. We develop efficient algorithms for single and multiple round approaches. For all three problems, we evaluate the efficiency of our algorithms through simulations. Our simulation results based on realistic energy models obtained from existing mobile and static sensor platforms show that our approaches significantly improve the network's performance and outperform existing approaches.

Use of Computer-Based Case Studies in a Problem-Solving Curriculum.

ERIC Educational Resources Information Center

Haworth, Ian S.; And Others

1997-01-01

Describes the use of three case studies, on computer, to enhance problem solving and critical thinking among doctoral pharmacy students in a physical chemistry course. Students are expected to use specific computer programs, spreadsheets, electronic mail, molecular graphics, word processing, online literature searching, and other computer-based…
Role of dislocations and carrier concentration in limiting the electron mobility of InN films grown by plasma assisted molecular beam epitaxy

NASA Astrophysics Data System (ADS)

Tangi, Malleswararao; De, Arpan; Shivaprasad, S. M.

2018-01-01

We report the molecular beam epitaxy growth of device quality InN films on GaN epilayer and nano-wall network (NWN) templates deposited on c-sapphire by varying the film thickness up to 1 μm. The careful experiments are directed towards obtaining high mobility InN layers having a low band gap with improved crystal quality. The dislocation density is quantified by using high resolution X-ray diffraction rocking curve broadening values of symmetric and asymmetric reflections, respectively. We observe that the dislocation density of the InN films grown on GaN NWN is less than that of the films grown on the GaN epilayer. This is attributed to the nanoepitaxial lateral overlayer growth (ELOG) process, where the presence of voids at the interface of InN/GaN NWN prevents the propagation of dislocation lines into the InN epilayers, thereby causing less defects in the overgrown InN films. Thus, this new adaptation of the nano-ELOG growth process enables us to prepare InN layers with high electron mobility. The obtained electron mobility of 2121 cm2/Vs for 1 μm thick InN/GaN NWN is comparable with the literature values of similar thickness InN films. Furthermore, in order to understand the reasons that limit electron mobility, the charge neutrality condition is employed to study the variation of electron mobility as a function of dislocation density and carrier concentration. Overall, this study provides a route to attaining improved crystal quality and electronic properties of InN films.
Security Measures to Protect Mobile Agents

NASA Astrophysics Data System (ADS)

Dadhich, Piyanka; Govil, M. C.; Dutta, Kamlesh

2010-11-01

The security issues of mobile agent systems have embarrassed its widespread implementation. Mobile agents that move around the network are not safe because the remote hosts that accommodate the agents initiates all kinds of attacks. These hosts try to analyze the agent's decision logic and their accumulated data. So, mobile agent security is the most challenging unsolved problems. The paper analyzes various security measures deeply. Security especially the attacks performed by hosts to the visiting mobile agent (the malicious hosts problem) is a major obstacle that prevents mobile agent technology from being widely adopted. Being the running environment for mobile agent, the host has full control over them and could easily perform many kinds of attacks against them.
An investigation into the use of the car as a mobile office.

PubMed

Eost, C; Flyte, M G

1998-10-01

In today's business environment people can no longer afford to be 'out of touch' when they are away from the office, with the result, the car has become a mobile office for many workers. The aims of this study were * to review current technology in the mobile office, * to determine problems of office working in the car, * to offer design solutions. Case studies gained an insight into working practices and problems in the car. Diaries quantified the types and amounts of work done in the car and an interview survey measured the extent of mobile office technology implemented into cars, problems relating to working in the car and some potential solutions. People do experience problems trying to do office work in their car. These problems include lack of space, lack of storage, nowhere flat to rest work on, inadequate temperature control in the car and poor communication facilities.
Comprehensive approach to intrinsic charge carrier mobility in conjugated organic molecules, macromolecules, and supramolecular architectures.

PubMed

Saeki, Akinori; Koizumi, Yoshiko; Aida, Takuzo; Seki, Shu

2012-08-21

Si-based inorganic electronics have long dominated the semiconductor industry. However, in recent years conjugated polymers have attracted increasing attention because such systems are flexible and offer the potential for low-cost, large-area production via roll-to-roll processing. The state-of-the-art organic conjugated molecular crystals can exhibit charge carrier mobilities (μ) that nearly match or even exceed that of amorphous silicon (1-10 cm(2) V(-1) s(-1)). The mean free path of the charge carriers estimated from these mobilities corresponds to the typical intersite (intermolecular) hopping distances in conjugated organic materials, which strongly suggests that the conduction model for the electronic band structure only applies to μ > 1 cm(2) V(-1) s(-1) for the translational motion of the charge carriers. However, to analyze the transport mechanism in organic electronics, researchers conventionally use a disorder formalism, where μ is usually less than 1 cm(2) V(-1) s(-1) and dominated by impurities, disorders, or defects that disturb the long-range translational motion. In this Account, we discuss the relationship between the alternating-current and direct-current mobilities of charge carriers, using time-resolved microwave conductivity (TRMC) and other techniques including field-effect transistor, time-of-flight, and space-charge limited current. TRMC measures the nanometer-scale mobility of charge carriers under an oscillating microwave electric field with no contact between the semiconductors and the metals. This separation allows us to evaluate the intrinsic charge carrier mobility with minimal trapping effects. We review a wide variety of organic electronics in terms of their charge carrier mobilities, and we describe recent studies of macromolecules, molecular crystals, and supramolecular architecture. For example, a rigid poly(phenylene-co-ethynylene) included in permethylated cyclodextrin shows a high intramolecular hole mobility of 0.5 cm(2) V(-1) s(-1), based on a combination of flash-photolysis TRMC and transient absorption spectroscopy (TAS) measurements. Single-crystal rubrene showed an ambipolarity with anisotropic charge carrier transport along each crystal axis on the nanometer scale. Finally, we describe the charge carrier mobility of a self-assembled nanotube consisting of a large π-plane of hexabenzocoronene (HBC) partially appended with an electron acceptor. The local (intratubular) charge carrier mobility reached 3 cm(2) V(-1) s(-1) for the nanotubes that possessed well-ordered π-stacking, but it dropped to 0.7 cm(2) V(-1) s(-1) in regions that contained greater amounts of the electron acceptor because those molecules reduced the structural integrity of π-stacked HBC arrays. Interestingly, the long-range (intertubular) charge carrier mobility was on the order of 10(-4) cm(2) V(-1) s(-1) and monotonically decreased when the acceptor content was increased. These results suggest the importance of investigating charge carrier mobilities by frequency-dependent charge carrier motion for the development of more efficient organic electronic devices.
Carrier mobility and scattering lifetime in electric double-layer gated few-layer graphene

NASA Astrophysics Data System (ADS)

Piatti, E.; Galasso, S.; Tortello, M.; Nair, J. R.; Gerbaldi, C.; Bruna, M.; Borini, S.; Daghero, D.; Gonnelli, R. S.

2017-02-01

We fabricate electric double-layer field-effect transistor (EDL-FET) devices on mechanically exfoliated few-layer graphene. We exploit the large capacitance of a polymeric electrolyte to study the transport properties of three, four and five-layer samples under a large induced surface charge density both above and below the glass transition temperature of the polymer. We find that the carrier mobility shows a strong asymmetry between the hole and electron doping regime. We then employ ab initio density functional theory (DFT) calculations to determine the average scattering lifetime from the experimental data. We explain its peculiar dependence on the carrier density in terms of the specific properties of the electrolyte we used in our experiments.
Cloud-assisted mobile-access of health data with privacy and auditability.

PubMed

Tong, Yue; Sun, Jinyuan; Chow, Sherman S M; Li, Pan

2014-03-01

Motivated by the privacy issues, curbing the adoption of electronic healthcare systems and the wild success of cloud service models, we propose to build privacy into mobile healthcare systems with the help of the private cloud. Our system offers salient features including efficient key management, privacy-preserving data storage, and retrieval, especially for retrieval at emergencies, and auditability for misusing health data. Specifically, we propose to integrate key management from pseudorandom number generator for unlinkability, a secure indexing method for privacy-preserving keyword search which hides both search and access patterns based on redundancy, and integrate the concept of attribute-based encryption with threshold signing for providing role-based access control with auditability to prevent potential misbehavior, in both normal and emergency cases.
Mobile Phone Usage and its Health Effects Among Adults in a Semi-Urban Area of Southern India.

PubMed

Stalin, P; Abraham, Sherin Billy; Kanimozhy, K; Prasad, R Vishnu; Singh, Zile; Purty, Anil J

2016-01-01

Worldwide, mobile phone usage has been increased dramatically which could affect the health of the people. India has the second largest number of mobile phone users. However there are only few studies conducted in India to assess its effects on health. To determine the prevalence and pattern of mobile phone usage and to assess the relationship between certain selected health problems and mobile phone usage among adults. Community-based cross-sectional study was conducted in Kottakuppam, a town panchayat in Villupuram district of Coastal Tamil Nadu, Southern India. It is a semi-urban area with a population of about 16,000. Majority of the residents are Muslim by religion and belong to different socio economic status. The study was approved by the Institutional Ethics Committee. A total of 2121 study participants were interviewed by the pre-final medical students through house-to-house survey using a pretested structured questionnaire. The questionnaire included the variables such as socio demographic profile, mobile phone usage and pattern, selected health problems, perceived benefits and threats and blood pressure. Selected health problems included headache, earache, neck pain, tinnitus, painful fingers, restlessness, morning tiredness, tingling fingers, fatigue, eye symptoms, sleep disturbance and hypertension. Only 2054 were included for data analysis using SPSS 17 version. Proportions were calculated. Chi-square test was used to measure the p-value. The p-value < 0.05 was considered as statistically significant. The prevalence of mobile phone usage was 70%. Calling facility (94.2%) was used more than the SMS (67.6%). Health problems like headache, earache, tinnitus, painful fingers and restlessness etc., were found to be positively associated with mobile phone usage. There was negative association between hypertension and mobile phone usage. The prevalence of mobile phone usage was high. There was significant association between selected health problems and mobile phone usage. In future, higher studies are required to confirm our findings.
Rylene and related diimides for organic electronics.

PubMed

Zhan, Xiaowei; Facchetti, Antonio; Barlow, Stephen; Marks, Tobin J; Ratner, Mark A; Wasielewski, Michael R; Marder, Seth R

2011-01-11

Organic electron-transporting materials are essential for the fabrication of organic p-n junctions, photovoltaic cells, n-channel field-effect transistors, and complementary logic circuits. Rylene diimides are a robust, versatile class of polycyclic aromatic electron-transport materials with excellent thermal and oxidative stability, high electron affinities, and, in many cases, high electron mobilities; they are, therefore, promising candidates for a variety of organic electronics applications. In this review, recent developments in the area of high-electron-mobility diimides based on rylenes and related aromatic cores, particularly perylene- and naphthalene-diimide-based small molecules and polymers, for application in high-performance organic field-effect transistors and photovoltaic cells are summarized and analyzed.
Use of interfacial layers to prolong hole lifetimes in hematite probed by ultrafast transient absorption spectroscopy

NASA Astrophysics Data System (ADS)

Paradzah, Alexander T.; Diale, Mmantsae; Maabong, Kelebogile; Krüger, Tjaart P. J.

2018-04-01

Hematite is a widely investigated material for applications in solar water oxidation due primarily to its small bandgap. However, full realization of the material continues to be hampered by fast electron-hole recombination rates among other weaknesses such as low hole mobility, short hole diffusion length and low conductivity. To address the problem of fast electron-hole recombination, researchers have resorted to growth of nano-structured hematite, doping and use of under-layers. Under-layer materials enhance the photo-current by minimising electron-hole recombination through suppressing of back electron flow from the substrate, such as fluorine-doped tin oxide (FTO), to hematite. We have carried out ultrafast transient absorption spectroscopy on hematite in which Nb2O5 and SnO2 materials were used as interfacial layers to enhance hole lifetimes. The transient absorption data was fit with four different lifetimes ranging from a few hundred femtoseconds to a few nanoseconds. We show that the electron-hole recombination is slower in samples where interfacial layers are used than in pristine hematite. We also develop a model through target analysis to illustrate the effect of under-layers on electron-hole recombination rates in hematite thin films.
Mobile device for disease diagnosis and data tracking in resource-limited settings.

PubMed

Chin, Curtis D; Cheung, Yuk Kee; Laksanasopin, Tassaneewan; Modena, Mario M; Chin, Sau Yin; Sridhara, Archana A; Steinmiller, David; Linder, Vincent; Mushingantahe, Jules; Umviligihozo, Gisele; Karita, Etienne; Mwambarangwe, Lambert; Braunstein, Sarah L; van de Wijgert, Janneke; Sahabo, Ruben; Justman, Jessica E; El-Sadr, Wafaa; Sia, Samuel K

2013-04-01

Collection of epidemiological data and care of patients are hampered by lack of access to laboratory diagnostic equipment and patients' health records in resource-limited settings. We engineered a low-cost mobile device that combines cell-phone and satellite communication technologies with fluid miniaturization techniques for performing all essential ELISA functions. We assessed the device's ability to perform HIV serodiagnostic testing in Rwanda and synchronize results in real time with electronic health records. We tested serum, plasma, and whole blood samples collected in Rwanda and on a commercially available sample panel made of mixed antibody titers. HIV testing on 167 Rwandan patients evaluated for HIV, viral hepatitis, and sexually transmitted infections yielded diagnostic sensitivity and specificity of 100% and 99%, respectively. Testing on 40 Rwandan whole-blood samples-using 1 μL of sample per patient-resulted in diagnostic sensitivity and specificity of 100% and 100%. The mobile device also successfully transmitted all whole-blood test results from a Rwandan clinic to a medical records database stored on the cloud. For all samples in the commercial panel, the device produced results in agreement with a leading ELISA test, including detection of weakly positive samples that were missed by existing rapid tests. The device operated autonomously with minimal user input, produced each result 10 times faster than benchtop ELISA, and consumed as little power as a mobile phone. A low-cost mobile device can perform a blood-based HIV serodiagnostic test with laboratory-level accuracy and real-time synchronization of patient health record data. © 2012 American Association for Clinical Chemistry
Impact, distress and HRQoL among Malaysian men and women with a mobility impairment.

PubMed

Misajon, RoseAnne; Manderson, Lenore; Pallant, Julie F; Omar, Zaliha; Bennett, Elizabeth; Rahim, Rameezan Begam Abdul

2006-12-12

Although non-communicable and chronic disease now accounts for 47% of the global burden of disease, little is known of the everyday experiences and social aspects of disability and disablement in middle and low income countries. This article aims to address this gap by exploring the subjective experience of mobility impairment in Malaysia. Specifically, it examines health-related quality of life and the impact and distress related to impaired mobility, and investigates any gender differences in relation to the experience of disability. The data were collected as part of an interdisciplinary, multi-country study known as RESILIENCE (Research into Social Inclusion, Locomotive Impairment and Empowerment through Networking, Collaboration and Education). Cluster sampling was used to administer the EQ-5D and the Perceived Impact of Problems Profile (PIPP) to 210 adults from Selangor state, west coast Peninsular Malaysia. The participants consisted of 94 males and 116 females, aged between 18-90 years (mean 60 years), with the majority being Malay. The majority of participants were also married, from rural areas and had primary education only. Very few participants lived alone. In addition, males were more likely to attribute their impaired mobility to an accident. The majority of participants with mobility impairment experienced a moderate to high level of pain/discomfort (79%) and anxiety/depression (72%), and at least some problems with performing usual activities (71%), as measured by the EQ-5D. In addition, using the Perceived Impact of Problems Profile (PIPP), participants also reported high levels of impact and distress related to participation in community life. In general, males reported higher impact and distress across several items, most significantly in regard to participation in community activities, moving around the neighbourhood, ability to live independently, and ability to assist their family members. This paper provides preliminary data regarding the health-related quality of life among Malaysians with impaired mobility, and highlights the multifaceted impact of disability and the importance of acknowledging the diverse cultural contexts in which disability can occur. It also raises questions regarding gender differences in the subjective experience of disability in Malaysia.
Impact, distress and HRQoL among Malaysian men and women with a mobility impairment

PubMed Central

Misajon, RoseAnne; Manderson, Lenore; Pallant, Julie F; Omar, Zaliha; Bennett, Elizabeth; Rahim, Rameezan Begam Abdul

2006-01-01

Background Although non-communicable and chronic disease now accounts for 47% of the global burden of disease, little is known of the everyday experiences and social aspects of disability and disablement in middle and low income countries. This article aims to address this gap by exploring the subjective experience of mobility impairment in Malaysia. Specifically, it examines health-related quality of life and the impact and distress related to impaired mobility, and investigates any gender differences in relation to the experience of disability. Methods The data were collected as part of an interdisciplinary, multi-country study known as RESILIENCE (Research into Social Inclusion, Locomotive Impairment and Empowerment through Networking, Collaboration and Education). Cluster sampling was used to administer the EQ-5D and the Perceived Impact of Problems Profile (PIPP) to 210 adults from Selangor state, west coast Peninsular Malaysia. Results The participants consisted of 94 males and 116 females, aged between 18–90 years (mean 60 years), with the majority being Malay. The majority of participants were also married, from rural areas and had primary education only. Very few participants lived alone. In addition, males were more likely to attribute their impaired mobility to an accident. The majority of participants with mobility impairment experienced a moderate to high level of pain/discomfort (79%) and anxiety/depression (72%), and at least some problems with performing usual activities (71%), as measured by the EQ-5D. In addition, using the Perceived Impact of Problems Profile (PIPP), participants also reported high levels of impact and distress related to participation in community life. In general, males reported higher impact and distress across several items, most significantly in regard to participation in community activities, moving around the neighbourhood, ability to live independently, and ability to assist their family members. Conclusion This paper provides preliminary data regarding the health-related quality of life among Malaysians with impaired mobility, and highlights the multifaceted impact of disability and the importance of acknowledging the diverse cultural contexts in which disability can occur. It also raises questions regarding gender differences in the subjective experience of disability in Malaysia. PMID:17156494
Impact of different environmental conditions on the aggregation of biogenic U(IV) nanoparticles synthesized by Desulfovibrio alaskensis G20

DOE Office of Scientific and Technical Information (OSTI.GOV)

Şengör, S. Sevinç; Singh, Gursharan; Dohnalkova, Alice

This study investigates the impact of specific environmental conditions on the formation of colloidal U(IV) nanoparticles by the sulfate reducing bacteria (SRB, Desulfovibrio alaskensis G20). The reduction of soluble U(VI) to less soluble U(IV) was quantitatively investigated under growth and non-growth conditions in bicarbonate or 1,4-piperazinediethanesulfonic acid (PIPES) buffered environments. The results showed that under non-growth conditions, the majority of the reduced U nanoparticles aggregated and precipitated out of solution. High resolution transmission electron microscopy revealed that only a very small fraction of cells had reduced U precipitates in the periplasmic spaces in the presence of PIPES buffer, whereas inmore » the presence of bicarbonate buffer, reduced U was also observed in the cytoplasm with greater aggregation of biogenic U(IV) particles at higher initial U(VI) concentrations. The same experiments were repeated under growth conditions using two different electron donors (lactate and pyruvate) and three electron acceptors (sulfate, fumarate, and thiosulfate). In contrast to the results of the non-growth experiments, even after 0.2 m filtration, the majority of biogenic U(IV) remained in the aqueous phase resulting in potentially mobile biogenic U(IV) nanoparticles. Size fractionation results showed that U(IV) aggregates were between 18 and 200 nm in diameter, and thus could be very mobile. The findings of this study are helpful to assess the size and potential mobility of reduced U nanoparticles under different environmental conditions, and would provide insights on their potential impact affecting U(VI) bioremediation efforts at subsurface contaminated sites.« less
The electromagnetic environment of hospitals: how it is affected by the strength of electromagnetic fields generated both inside and outside the hospital.

PubMed

Hanada, Eisuke

2007-01-01

Most problems with the electromagnetic environment of medical institutions have been related to radiated electromagnetic fields and have been constructed from reports about electromagnetic interference (EMI) with electronic medical equipment by the radio waves emitted from mobile telephone handsets. However, radiated electromagnetic fields are just one of the elements. For example, little attention has been placed on problems with the electric power source. Apparatus for clinical treatment and diagnosis that use electric power sources have come into wide use in hospitals. Hospitals must pay careful attention to all elements of the electromagnetic environment. Herein, I will show examples of measurements and measuring methods for radiated electromagnetic fields, static magnetic fields, and power-source noise, common components of the medical electromagnetic environment.
Liquid crystals for organic thin-film transistors

PubMed Central

Iino, Hiroaki; Usui, Takayuki; Hanna, Jun-ichi

2015-01-01

Crystalline thin films of organic semiconductors are a good candidate for field effect transistor (FET) materials in printed electronics. However, there are currently two main problems, which are associated with inhomogeneity and poor thermal durability of these films. Here we report that liquid crystalline materials exhibiting a highly ordered liquid crystal phase of smectic E (SmE) can solve both these problems. We design a SmE liquid crystalline material, 2-decyl-7-phenyl-[1]benzothieno[3,2-b][1]benzothiophene (Ph-BTBT-10), for FETs and synthesize it. This material provides uniform and molecularly flat polycrystalline thin films reproducibly when SmE precursor thin films are crystallized, and also exhibits high durability of films up to 200 °C. In addition, the mobility of FETs is dramatically enhanced by about one order of magnitude (over 10 cm2 V−1 s−1) after thermal annealing at 120 °C in bottom-gate-bottom-contact FETs. We anticipate the use of SmE liquid crystals in solution-processed FETs may help overcome upcoming difficulties with novel technologies for printed electronics. PMID:25857435
Liquid crystals for organic thin-film transistors.

PubMed

Iino, Hiroaki; Usui, Takayuki; Hanna, Jun-ichi

2015-04-10

Crystalline thin films of organic semiconductors are a good candidate for field effect transistor (FET) materials in printed electronics. However, there are currently two main problems, which are associated with inhomogeneity and poor thermal durability of these films. Here we report that liquid crystalline materials exhibiting a highly ordered liquid crystal phase of smectic E (SmE) can solve both these problems. We design a SmE liquid crystalline material, 2-decyl-7-phenyl-[1]benzothieno[3,2-b][1]benzothiophene (Ph-BTBT-10), for FETs and synthesize it. This material provides uniform and molecularly flat polycrystalline thin films reproducibly when SmE precursor thin films are crystallized, and also exhibits high durability of films up to 200 °C. In addition, the mobility of FETs is dramatically enhanced by about one order of magnitude (over 10 cm(2) V(-1) s(-1)) after thermal annealing at 120 °C in bottom-gate-bottom-contact FETs. We anticipate the use of SmE liquid crystals in solution-processed FETs may help overcome upcoming difficulties with novel technologies for printed electronics.
Liquid crystals for organic thin-film transistors

NASA Astrophysics Data System (ADS)

Iino, Hiroaki; Usui, Takayuki; Hanna, Jun-Ichi

2015-04-01

Crystalline thin films of organic semiconductors are a good candidate for field effect transistor (FET) materials in printed electronics. However, there are currently two main problems, which are associated with inhomogeneity and poor thermal durability of these films. Here we report that liquid crystalline materials exhibiting a highly ordered liquid crystal phase of smectic E (SmE) can solve both these problems. We design a SmE liquid crystalline material, 2-decyl-7-phenyl-[1]benzothieno[3,2-b][1]benzothiophene (Ph-BTBT-10), for FETs and synthesize it. This material provides uniform and molecularly flat polycrystalline thin films reproducibly when SmE precursor thin films are crystallized, and also exhibits high durability of films up to 200 °C. In addition, the mobility of FETs is dramatically enhanced by about one order of magnitude (over 10 cm2 V-1 s-1) after thermal annealing at 120 °C in bottom-gate-bottom-contact FETs. We anticipate the use of SmE liquid crystals in solution-processed FETs may help overcome upcoming difficulties with novel technologies for printed electronics.
Charge-carrier mobilities in Cd(0.8)Zn(0.2)Te single crystals used as nuclear radiation detectors

NASA Technical Reports Server (NTRS)

Burshtein, Z.; Jayatirtha, H. N.; Burger, A.; Butler, J. F.; Apotovsky, B.; Doty, F. P.

1993-01-01

Charge-carrier mobilities were measured for the first time in Cd(0.8)Zn(0.2)Te single crystals using time-of-flight measurements of charge carriers produced by short (10 ns) light pulses from a frequency-doubled Nd:YAG laser (532 nm). The electron mobility displayed a T exp -1.1 dependence on the absolute temperature T in the range 200-320 K, with a room-temperature mobility of 1350 sq cm/V s. The hole mobility displayed a T exp -2.0 dependence in the same temperature range, with a room-temperature mobility of 120 sq cm/V s. Cd(0.8)Zn(0.2)Te appears to be a very favorable material for a room-temperature electronic nuclear radiation detector.
Large thermoelectric power factor from crystal symmetry-protected non-bonding orbital in half-Heuslers.

PubMed

Zhou, Jiawei; Zhu, Hangtian; Liu, Te-Huan; Song, Qichen; He, Ran; Mao, Jun; Liu, Zihang; Ren, Wuyang; Liao, Bolin; Singh, David J; Ren, Zhifeng; Chen, Gang

2018-04-30

Modern society relies on high charge mobility for efficient energy production and fast information technologies. The power factor of a material-the combination of electrical conductivity and Seebeck coefficient-measures its ability to extract electrical power from temperature differences. Recent advancements in thermoelectric materials have achieved enhanced Seebeck coefficient by manipulating the electronic band structure. However, this approach generally applies at relatively low conductivities, preventing the realization of exceptionally high-power factors. In contrast, half-Heusler semiconductors have been shown to break through that barrier in a way that could not be explained. Here, we show that symmetry-protected orbital interactions can steer electron-acoustic phonon interactions towards high mobility. This high-mobility regime enables large power factors in half-Heuslers, well above the maximum measured values. We anticipate that our understanding will spark new routes to search for better thermoelectric materials, and to discover high electron mobility semiconductors for electronic and photonic applications.

AlGaN/GaN high electron mobility transistor grown on GaN template substrate by molecule beam epitaxy system

NASA Astrophysics Data System (ADS)

Tsai, Jenn-Kai; Chen, Y. L.; Gau, M. H.; Pang, W. Y.; Hsu, Y. C.; Lo, Ikai; Hsieh, C. H.

2008-03-01

In this study, AlGaN/GaN high electron mobility transistor (HEMT) structure was grow on GaN template substrate radio frequency plasma assisted molecular beam epitaxy (MBE) equipped with an EPI UNI-Bulb nitrogen plasma source. The undoped GaN template substrate was grown on c-sapphire substrate by metal organic vapor phase epitaxy system (MOPVD). After growth of MOVPE and MBE, the samples are characterized by double crystal X-ray diffraction (XRD), transmission electron microscopy (TEM), field emission scanning electron microscopy (SEM), atomic force microscopy (AFM), and Hall effect measurements. We found that the RMS roughness of template substrate play the major role in got the high value of mobility on AlGaN/GaN HEMT. When the roughness was lower than 0.77 nm in a 25 μm x 25 μm area, the mobility of HEMT at the temperature of 77 K was over 10000 cm^2/Vs.
First-principles studies of electron transport in Ga2O3

NASA Astrophysics Data System (ADS)

Kang, Youngho; Krishnaswamy, Karthik; Peelaers, Hartwin; van de Walle, Chris G.

Ga2O3 is a wide-gap semiconductor with a monoclinic crystal structure and a band gap of 4.8 eV. Its high carrier mobility and large band gap have attracted a lot of attention for use in high power electronics and transparent conductors. Despite its potential for adoption in these applications, an understanding of its carrier transport properties is still lacking. In this study we use first-principles calculations to analyze and compute the electron scattering rates in Ga2O3. Scattering due to ionized impurities and polar longitudinal-optical (LO) phonon is taken into account. We find that the electron mobility is nearly isotropic, despite the low-symmetry monoclinic structure of Ga2O3. At low carrier densities ( 1017 cm-3), the mobility is limited by LO phonon scattering. Scattering by ionized impurities becomes increasingly important at higher carrier densities. This type of scattering is enhanced when compensating native point defects are present; in particular, gallium vacancies, which are triply negatively charged, can have a strong effect on mobility. These effects explain the downturn in mobility observed in experiments at high carrier densities. This work was supported by ARO and NSF.
Proceedings of the AFOSR Special Conference on Prime-Power for High Energy Space Systems, Norfolk, Virginia, 22-25 February 1982. Volume 2

DTIC Science & Technology

1982-02-25

However, because the mobility of the ions is much smaller than the mobility of the electrons (for cesium i = 1/500 Me), and because of ion...space applications of this high temperature in- sulation. Use of glass-alumina insulation for motors in mobile applications would reduce cooling...present and/or mobile only during irradiation. VII-7-7 WS 710 01AS$ AesowRpIOr MEA8IJRtED MOt AN FTER L5 MvV ELECTRON NtADIATION Fig. 7 -- Growth of
Photonic sensor applications in transportation security

NASA Astrophysics Data System (ADS)

Krohn, David A.

2007-09-01

There is a broad range of security sensing applications in transportation that can be facilitated by using fiber optic sensors and photonic sensor integrated wireless systems. Many of these vital assets are under constant threat of being attacked. It is important to realize that the threats are not just from terrorism but an aging and often neglected infrastructure. To specifically address transportation security, photonic sensors fall into two categories: fixed point monitoring and mobile tracking. In fixed point monitoring, the sensors monitor bridge and tunnel structural health and environment problems such as toxic gases in a tunnel. Mobile tracking sensors are being designed to track cargo such as shipboard cargo containers and trucks. Mobile tracking sensor systems have multifunctional sensor requirements including intrusion (tampering), biochemical, radiation and explosives detection. This paper will review the state of the art of photonic sensor technologies and their ability to meet the challenges of transportation security.
Terahertz time-domain magnetospectroscopy of a high-mobility two-dimensional electron gas.

PubMed

Wang, Xiangfeng; Hilton, David J; Ren, Lei; Mittleman, Daniel M; Kono, Junichiro; Reno, John L

2007-07-01

We have observed cyclotron resonance in a high-mobility GaAs/AlGaAs two-dimensional electron gas by using the techniques of terahertz time-domain spectroscopy combined with magnetic fields. From this, we calculate the real and imaginary parts of the diagonal elements of the magnetoconductivity tensor, which in turn allows us to extract the concentration, effective mass, and scattering time of the electrons in the sample. We demonstrate the utility of ultrafast terahertz spectroscopy, which can recover the true linewidth of cyclotron resonance in a high-mobility (>10(6) cm(2)V(-1)s(-1)) sample without being affected by the saturation effect.
Ambipolar nature of dimethyl benzo difuran (DMBDF) molecule: A charge transport study

NASA Astrophysics Data System (ADS)

Sahoo, Smruti Ranjan; Sahu, Sridhar

2017-05-01

We describe a theoretical study of the charge transport properties of the organic dimethyl benzo difuran (DMBDF) molecule based on density functional theory (DFT). Reorganization energy, ionization potential (IP), electron affinity (EA), energy gaps, transfer integral (t) and charge mobility (μ) has been studied to depict the transport properties in the conjugated organic molecules. We computed, large homo transfer integral and IP value leading to high hole mobility (4.46 cm2/V sec). However, the electron reorganization energy (0.34 eV) and the electron mobility of 1.62 cm2/V sec, infers that the DMBDF organic molecule bears an ambipolar character.
Theoretical predictions on the electronic structure and charge carrier mobility in 2D Phosphorus sheets

PubMed Central

Xiao, Jin; Long, Mengqiu; Zhang, Xiaojiao; Ouyang, Jun; Xu, Hui; Gao, Yongli

2015-01-01

We have investigated the electronic structure and carrier mobility of four types of phosphorous monolayer sheet (α-P, β-P,γ-P and δ-P) using density functional theory combined with Boltzmann transport method and relaxation time approximation. It is shown that α-P, β-P and γ-P are indirect gap semiconductors, while δ-P is a direct one. All four sheets have ultrahigh carrier mobility and show anisotropy in-plane. The highest mobility value is ~3 × 105 cm2V−1s−1, which is comparable to that of graphene. Because of the huge difference between the hole and electron mobilities, α-P, γ-P and δ-P sheets can be considered as n-type semiconductors, and β-P sheet can be considered as a p-type semiconductor. Our results suggest that phosphorous monolayer sheets can be considered as a new type of two dimensional materials for applications in optoelectronics and nanoelectronic devices. PMID:26035176
High Mobility SiGe/Si Transistor Structures on Sapphire Substrates Using Ion Implantation

NASA Technical Reports Server (NTRS)

Alterovitz, S. A.; Mueller, C. H.; Croke, E. T.

2003-01-01

High mobility n-type SiGe/Si transistor structures have been fabricated on sapphire substrates by ion implanting phosphorus ions into strained 100 Angstrom thick silicon channels for the first time. The strained Si channels were sandwiched between Si(sub 0.7)Ge(sub 0.3) layers, which, in turn, were deposited on Si(sub 0.7)Ge(sub 0.3) virtual substrates and graded SiGe buffer layers. After the molecular beam epitaxy (MBE) film growth process was completed, ion thick silicon channels implantation and post-annealing were used to introduce donors. The phosphorous ions were preferentially located in the Si channel at a peak concentration of approximately 1x10(exp 18)/cu cm. Room temperature electron mobilities exceeding 750 sq cm/V-sec at carrier densities of 1x10(exp 12)/sq cm were measured. Electron concentration appears to be the key factor that determines mobility, with the highest mobility observed for electron densities in the 1 - 2x10(exp 12)/sq cm range.
Development of eHOME, a Mobile Instrument for Reporting, Monitoring, and Consulting Drug-Related Problems in Home Care: Human-Centered Design Study

PubMed Central

Sino, Carolina Geertruida Maria; Heerdink, Eibert Rob; Schuurmans, Marieke Joanna

2018-01-01

Background Home care patients often use many medications and are prone to drug-related problems (DRPs). For the management of problems related to drug use, home care could add to the multidisciplinary expertise of general practitioners (GPs) and pharmacists. The home care observation of medication-related problems by home care employees (HOME)-instrument is paper-based and assists home care workers in reporting potential DRPs. To facilitate the multiprofessional consultation, a digital report of DRPs from the HOME-instrument and digital monitoring and consulting of DRPs between home care and general practices and pharmacies is desired. Objective The objective of this study was to develop an electronic HOME system (eHOME), a mobile version of the HOME-instrument that includes a monitoring and a consulting system for primary care. Methods The development phase of the Medical Research Council (MRC) framework was followed in which an iterative human-centered design (HCD) approach was applied. The approach involved a Delphi round for the context of use and user requirements analysis of the digital HOME-instrument and the monitoring and consulting system followed by 2 series of pilots for testing the usability and redesign. Results By using an iterative design approach and by involving home care workers, GPs, and pharmacists throughout the process as informants, design partners, and testers, important aspects that were crucial for system realization and user acceptance were revealed. Through the report webpage interface, which includes the adjusted content of the HOME-instrument and added home care practice–based problems, home care workers can digitally report observed DRPs. Furthermore, it was found that the monitoring and consulting webpage interfaces enable digital consultation between home care and general practices and pharmacies. The webpages were considered convenient, clear, easy, and usable. Conclusions By employing an HCD approach, the eHOME-instrument was found to be an easy-to-use system. The systematic approach promises a valuable contribution for the future development of digital mobile systems of paper-based tools. PMID:29514771
Development of eHOME, a Mobile Instrument for Reporting, Monitoring, and Consulting Drug-Related Problems in Home Care: Human-Centered Design Study.

PubMed

Dijkstra, Nienke Elske; Sino, Carolina Geertruida Maria; Heerdink, Eibert Rob; Schuurmans, Marieke Joanna

2018-03-07

Home care patients often use many medications and are prone to drug-related problems (DRPs). For the management of problems related to drug use, home care could add to the multidisciplinary expertise of general practitioners (GPs) and pharmacists. The home care observation of medication-related problems by home care employees (HOME)-instrument is paper-based and assists home care workers in reporting potential DRPs. To facilitate the multiprofessional consultation, a digital report of DRPs from the HOME-instrument and digital monitoring and consulting of DRPs between home care and general practices and pharmacies is desired. The objective of this study was to develop an electronic HOME system (eHOME), a mobile version of the HOME-instrument that includes a monitoring and a consulting system for primary care. The development phase of the Medical Research Council (MRC) framework was followed in which an iterative human-centered design (HCD) approach was applied. The approach involved a Delphi round for the context of use and user requirements analysis of the digital HOME-instrument and the monitoring and consulting system followed by 2 series of pilots for testing the usability and redesign. By using an iterative design approach and by involving home care workers, GPs, and pharmacists throughout the process as informants, design partners, and testers, important aspects that were crucial for system realization and user acceptance were revealed. Through the report webpage interface, which includes the adjusted content of the HOME-instrument and added home care practice-based problems, home care workers can digitally report observed DRPs. Furthermore, it was found that the monitoring and consulting webpage interfaces enable digital consultation between home care and general practices and pharmacies. The webpages were considered convenient, clear, easy, and usable. By employing an HCD approach, the eHOME-instrument was found to be an easy-to-use system. The systematic approach promises a valuable contribution for the future development of digital mobile systems of paper-based tools. ©Nienke Elske Dijkstra, Carolina Geertruida Maria Sino, Eibert Rob Heerdink, Marieke Joanna Schuurmans. Originally published in JMIR Human Factors (http://humanfactors.jmir.org), 07.03.2018.
The coral reefs optimization algorithm: a novel metaheuristic for efficiently solving optimization problems.

PubMed

Salcedo-Sanz, S; Del Ser, J; Landa-Torres, I; Gil-López, S; Portilla-Figueras, J A

2014-01-01

This paper presents a novel bioinspired algorithm to tackle complex optimization problems: the coral reefs optimization (CRO) algorithm. The CRO algorithm artificially simulates a coral reef, where different corals (namely, solutions to the optimization problem considered) grow and reproduce in coral colonies, fighting by choking out other corals for space in the reef. This fight for space, along with the specific characteristics of the corals' reproduction, produces a robust metaheuristic algorithm shown to be powerful for solving hard optimization problems. In this research the CRO algorithm is tested in several continuous and discrete benchmark problems, as well as in practical application scenarios (i.e., optimum mobile network deployment and off-shore wind farm design). The obtained results confirm the excellent performance of the proposed algorithm and open line of research for further application of the algorithm to real-world problems.
The Coral Reefs Optimization Algorithm: A Novel Metaheuristic for Efficiently Solving Optimization Problems

PubMed Central

Salcedo-Sanz, S.; Del Ser, J.; Landa-Torres, I.; Gil-López, S.; Portilla-Figueras, J. A.

2014-01-01

This paper presents a novel bioinspired algorithm to tackle complex optimization problems: the coral reefs optimization (CRO) algorithm. The CRO algorithm artificially simulates a coral reef, where different corals (namely, solutions to the optimization problem considered) grow and reproduce in coral colonies, fighting by choking out other corals for space in the reef. This fight for space, along with the specific characteristics of the corals' reproduction, produces a robust metaheuristic algorithm shown to be powerful for solving hard optimization problems. In this research the CRO algorithm is tested in several continuous and discrete benchmark problems, as well as in practical application scenarios (i.e., optimum mobile network deployment and off-shore wind farm design). The obtained results confirm the excellent performance of the proposed algorithm and open line of research for further application of the algorithm to real-world problems. PMID:25147860
Quantum transport properties of carbon nanotube field-effect transistors with electron-phonon coupling

NASA Astrophysics Data System (ADS)

Ishii, Hiroyuki; Kobayashi, Nobuhiko; Hirose, Kenji

2007-11-01

We investigated the electron-phonon coupling effects on the electronic transport properties of metallic (5,5)- and semiconducting (10,0)-carbon nanotube devices. We calculated the conductance and mobility of the carbon nanotubes with micron-order lengths at room temperature, using the time-dependent wave-packet approach based on the Kubo-Greenwood formula within a tight-binding approximation. We investigated the scattering effects of both longitudinal acoustic and optical phonon modes on the transport properties. The electron-optical phonon coupling decreases the conductance around the Fermi energy for the metallic carbon nanotubes, while the conductance of semiconductor nanotubes is decreased around the band edges by the acoustic phonons. Furthermore, we studied the Schottky-barrier effects on the mobility of the semiconducting carbon nanotube field-effect transistors for various gate voltages. We clarified how the electron mobilities of the devices are changed by the acoustic phonon.
Phonon-electron coupling and tunneling effect on charge transport in organic semi-conductor crystals of Cn-BTBT.

PubMed

Zhou, Yecheng; Deng, Wei-Qiao; Zhang, Hao-Li

2016-09-14

Cn-[1]benzothieno[3,2-b][1]-benzothiophene (BTBT) crystals show very high hole mobilities in experiments. These high mobilities are beyond existing theory prediction. Here, we employed different quantum chemistry methods to investigate charge transfer in Cn-BTBT crystals and tried to find out the reasons for the underestimation in the theory. It was found that the hopping rate estimated by the Fermi Golden Rule is higher than that of the Marcus theory due to the high temperature approximation and failure at the classic limit. More importantly, molecular dynamics simulations revealed that the phonon induced fluctuation of electronic transfer integral is much larger than the average of the electronic transfer integral itself. Mobilities become higher if simulations implement the phonon-electron coupling. This conclusion indicates that the phonon-electron coupling promotes charge transfer in organic semi-conductors at room temperature.
Phonon-electron coupling and tunneling effect on charge transport in organic semi-conductor crystals of Cn-BTBT

NASA Astrophysics Data System (ADS)

Zhou, Yecheng; Deng, Wei-Qiao; Zhang, Hao-Li

2016-09-01

Cn-[1]benzothieno[3,2-b][1]-benzothiophene (BTBT) crystals show very high hole mobilities in experiments. These high mobilities are beyond existing theory prediction. Here, we employed different quantum chemistry methods to investigate charge transfer in Cn-BTBT crystals and tried to find out the reasons for the underestimation in the theory. It was found that the hopping rate estimated by the Fermi Golden Rule is higher than that of the Marcus theory due to the high temperature approximation and failure at the classic limit. More importantly, molecular dynamics simulations revealed that the phonon induced fluctuation of electronic transfer integral is much larger than the average of the electronic transfer integral itself. Mobilities become higher if simulations implement the phonon-electron coupling. This conclusion indicates that the phonon-electron coupling promotes charge transfer in organic semi-conductors at room temperature.
The Problem of Developing Professional Mobility of Teachers in the Works of Foreign Scholars

ERIC Educational Resources Information Center

Pavlenko, Marina

2017-01-01

The article analyzes the positions of foreign and domestic scholars on the problem of developing professional mobility of teachers. It has been stated that today professional mobility is a necessary component of training a skilled worker. It has been indicated that the teacher possesses an appropriate set of competences that provide an opportunity…
Statistical Inference-Based Cache Management for Mobile Learning

ERIC Educational Resources Information Center

Li, Qing; Zhao, Jianmin; Zhu, Xinzhong

2009-01-01

Supporting efficient data access in the mobile learning environment is becoming a hot research problem in recent years, and the problem becomes tougher when the clients are using light-weight mobile devices such as cell phones whose limited storage space prevents the clients from holding a large cache. A practical solution is to store the cache…
Development of a Mobile Learning System Based on a Collaborative Problem-Posing Strategy

ERIC Educational Resources Information Center

Sung, Han-Yu; Hwang, Gwo-Jen; Chang, Ya-Chi

2016-01-01

In this study, a problem-posing strategy is proposed for supporting collaborative mobile learning activities. Accordingly, a mobile learning environment has been developed, and an experiment on a local culture course has been conducted to evaluate the effectiveness of the proposed approach. Three classes of an elementary school in southern Taiwan…
78 FR 63492 - Certain Electronic Devices, Including Mobile Phones and Tablet Computers, and Components Thereof...

Federal Register 2010, 2011, 2012, 2013, 2014

2013-10-24

... INTERNATIONAL TRADE COMMISSION [Investigation No. 337-TA-847] Certain Electronic Devices, Including Mobile Phones and Tablet Computers, and Components Thereof; Notice of Request for Statements on the Public Interest AGENCY: U.S. International Trade Commission. ACTION: Notice. SUMMARY: Notice is...
Electronic Reading and Digital Library Technologies: Understanding Learner Expectation and Usage Intent for Mobile Learning

ERIC Educational Resources Information Center

Hyman, Jack A.; Moser, Mary T.; Segala, Laura N.

2014-01-01

Mobile information technology is changing the education landscape by offering learners the opportunity to engage in asynchronous, ubiquitous instruction. While there is a proliferation of mobile content management systems being developed for the mobile Web and stand-alone mobile applications, few studies have addressed learner expectations and…

A Service Oriented Architecture to Integrate Mobile Assessment in Learning Management Systems

ERIC Educational Resources Information Center

Riad, A. M.; El-Ghareeb, H. A.

2008-01-01

Mobile Learning (M-Learning) is an approach to E-Learning that utilizes mobile devices. Learning Management System (LMS) should enable M-Learning. Unfortunately, M-Learning is not the same at each educational institution. Assessment is one of the learning activities that can be achieved electronically and via mobile device. Mobile assessment…
The development of an indoor mobility course for the evaluation of electronic mobility aids for persons who are visually impaired.

PubMed

Roentgen, Uta R; Gelderblom, Gert Jan; de Witte, Luc P

2012-01-01

To develop a suitable mobility course for the assessment of mobility performance as part of a user evaluation of Electronic Mobility Aids (EMA) aimed at obstacle detection and orientation. A review of the literature led to a list of critical factors for the assessment of mobility performance of persons who are visually impaired. Based upon that list, method, test situations, and determining elements were selected and presented to Dutch orientation and mobility experts. Due to expert advice and a pilot study, minor changes were made and the final version was used for the evaluation of two EMA by eight persons who are visually impaired. The results of the literature study are summarized in an overview of critical factors for the assessment of the mobility performance of persons who are visually impaired. Applied to the requirements of the above mentioned user evaluation a replicable indoor mobility course has been described in detail and tested. Based upon evidence from literature an indoor mobility course has been developed, which was sensitive to assess differences in mobility incidents and obstacle detection when using an EMA compared to the regular mobility aid. Experts' opinion confirmed its face and content validity.
On the physics of electron transfer (drift) in the substance: about the reason of “abnormal” fast transfer of electrons in the plasma of tokamak and at known Bohm’s diffusion

NASA Astrophysics Data System (ADS)

Boriev, I. A.

2018-03-01

An analysis of the problem of so-called “abnormal” fast transfer of electrons in tokamak plasma, which turned out much faster than the result of accepted calculation, is given. Such transfer of hot electrons leads to unexpectedly fast destruction of the inner tokamak wall with ejection of its matter in plasma volume, what violates a condition of plasma confinement for controlled thermonuclear fusion. It is shown, taking into account real physics of electron drift in the gas (plasma) and using the conservation law for momentum of electron transfer (drift), that the drift velocity of elastically scattered electrons should be significantly greater than that of accepted calculation. The reason is that the relaxation time of the momentum of electron transfer, to which the electron drift velocity is proportional, is significantly greater (from 16 up to 4 times) than the electron free path time. Therefore, generally accepted replacement of the relaxation time, which is unknown a priori, by the electron free path time, leads to significant (16 times for thermal electrons) underestimation of electron drift velocity (mobility). This result means, that transfer of elastically (and isotropically) scattered electrons in the gas phase should be so fast, and corresponds to multiplying coefficient (16), introduced by D. Bohm to explain the observed by him “abnormal” fast diffusion of electrons.
Magnetotransport studies of mobility limiting mechanisms in undoped Si/SiGe heterostructures

NASA Astrophysics Data System (ADS)

Mi, X.; Hazard, T. M.; Payette, C.; Wang, K.; Zajac, D. M.; Cady, J. V.; Petta, J. R.

2015-07-01

We perform detailed magnetotransport studies on two-dimensional electron gases (2DEGs) formed in undoped Si/SiGe heterostructures in order to identify the electron mobility limiting mechanisms. By analyzing data from 26 different heterostructures, we observe a strong correlation between the background oxygen concentration in the Si quantum well and the maximum mobility. The highest-quality wafer supports a 2DEG with mobility μ =160 000 cm 2/Vs at a density n =2.17 ×1011 /cm 2 and exhibits a metal-to-insulator transition at a critical density nc=0.46 ×1011 /cm 2. We extract a valley splitting Δv˜150 μ eV at a magnetic field B =1.8 T. These results provide evidence that undoped Si/SiGe heterostructures are suitable for the fabrication of few-electron quantum dots.
Electron mobility in modulation-doped heterostructures

NASA Technical Reports Server (NTRS)

Walukiewicz, W.; Ruda, H. E.; Lagowski, J.; Gatos, H. C.

1984-01-01

A model for electron mobility in a two-dimensional electron gas confined in a triangular well was developed. All major scattering processes (deformation potential and piezoelectric acoustic, polar optical, ionized impurity, and alloy disorder) were included, as well as intrasubband and intersubband scattering. The model is applied to two types of modulation-doped heterostructures, namely GaAs-GaAlAs and In(0.53)Ga(0.47)As-Al(0.52)In(0.48)As. In the former case, phonons and remote ionized impurities ultimately limit the mobility, whereas in the latter, alloy disorder is a predominant scattering process at low temperatures. The calculated mobilities are in very good agreement with recently reported experimental characteristics for both GaAs-Ga(1-x)Al(x)As and In(0.53)Ga(0.47)As-Al(0.52)In(0.48)As modulation-doped heterostructures.
Ab initio calculation of electron–phonon coupling in monoclinic β-Ga{sub 2}O{sub 3} crystal

DOE Office of Scientific and Technical Information (OSTI.GOV)

Ghosh, Krishnendu, E-mail: kghosh3@buffalo.edu; Singisetti, Uttam, E-mail: uttamsin@buffalo.edu

2016-08-15

The interaction between electrons and vibrational modes in monoclinic β-Ga{sub 2}O{sub 3} is theoretically investigated using ab-initio calculations. The large primitive cell of β-Ga{sub 2}O{sub 3} gives rise to 30 phonon modes all of which are taken into account in transport calculation. The electron-phonon interaction is calculated under density functional perturbation theory and then interpolated using Wannier–Fourier interpolation. The long-range interaction elements between electrons and polar optical phonon (POP) modes are calculated separately using the Born effective charge tensor. The direction dependence of the long-range POP coupling in a monoclinic crystal is explored and is included in the transport calculations.more » Scattering rate calculations are done using the Fermi golden rule followed by solving the Boltzmann transport equation using the Rode's method to estimate low field mobility. A room temperature mobility of 115 cm{sup 2}/V s is observed. Comparison with recent experimentally reported mobility is done for a wide range of temperatures (30 K–650 K). It is also found that the POP interaction dominates the electron mobility under low electric field conditions. The relative contribution of the different POP modes is analyzed and the mode 21 meV POP is found to have the highest impact on low field electron mobility at room temperature.« less
Association of Nondisease-Specific Problems with Mortality, Long-Term Care, and Functional Impairment among Older Adults Who Require Skilled Nursing Care after Dialysis Initiation

PubMed Central

Plantinga, Laura; Hall, Rasheeda K.; Mirk, Anna; Zhang, Rebecca; Kutner, Nancy

2016-01-01

Background and objectives The majority of older adults who initiate dialysis do so during a hospitalization, and these patients may require post-acute skilled nursing facility (SNF) care. For these patients, a focus on nondisease-specific problems, including cognitive impairment, depressive symptoms, exhaustion, falls, impaired mobility, and polypharmacy, may be more relevant to outcomes than the traditional disease-oriented approach. However, the association of the burden of nondisease-specific problems with mortality, transition to long-term care (LTC), and functional impairment among older adults receiving SNF care after dialysis initiation has not been studied. Design, setting, participants, & measurements We identified 40,615 Medicare beneficiaries ≥65 years old who received SNF care after dialysis initiation between 2000 and 2006 by linking renal disease registry data with the Minimum Data Set. Nondisease-specific problems were ascertained from the Minimum Data Set. We defined LTC as ≥100 SNF days and functional impairment as dependence in all four essential activities of daily living at SNF discharge. Associations of the number of nondisease-specific problems (≤1, 2, 3, and 4–6) with 6-month mortality, LTC, and functional impairment were examined. Results Overall, 39.2% of patients who received SNF care after dialysis initiation died within 6 months. Compared with those with ≤1 nondisease-specific problems, multivariable adjusted hazard ratios (95% confidence interval) for mortality were 1.26 (1.19 to 1.32), 1.40 (1.33 to 1.48), and 1.66 (1.57 to 1.76) for 2, 3, and 4–6 nondisease-specific problems, respectively. Among those who survived, 37.1% required LTC; of those remaining who did not require LTC, 74.7% had functional impairment. A higher likelihood of transition to LTC (among those who survived 6 months) and functional impairment (among those who survived and did not require LTC) was seen with a higher number of problems. Conclusions Identifying nondisease-specific problems may help patients and families anticipate LTC needs and functional impairment after dialysis initiation. PMID:27733436
Association of Nondisease-Specific Problems with Mortality, Long-Term Care, and Functional Impairment among Older Adults Who Require Skilled Nursing Care after Dialysis Initiation.

PubMed

Bowling, C Barrett; Plantinga, Laura; Hall, Rasheeda K; Mirk, Anna; Zhang, Rebecca; Kutner, Nancy

2016-12-07

The majority of older adults who initiate dialysis do so during a hospitalization, and these patients may require post-acute skilled nursing facility (SNF) care. For these patients, a focus on nondisease-specific problems, including cognitive impairment, depressive symptoms, exhaustion, falls, impaired mobility, and polypharmacy, may be more relevant to outcomes than the traditional disease-oriented approach. However, the association of the burden of nondisease-specific problems with mortality, transition to long-term care (LTC), and functional impairment among older adults receiving SNF care after dialysis initiation has not been studied. We identified 40,615 Medicare beneficiaries ≥65 years old who received SNF care after dialysis initiation between 2000 and 2006 by linking renal disease registry data with the Minimum Data Set. Nondisease-specific problems were ascertained from the Minimum Data Set. We defined LTC as ≥100 SNF days and functional impairment as dependence in all four essential activities of daily living at SNF discharge. Associations of the number of nondisease-specific problems (≤1, 2, 3, and 4-6) with 6-month mortality, LTC, and functional impairment were examined. Overall, 39.2% of patients who received SNF care after dialysis initiation died within 6 months. Compared with those with ≤1 nondisease-specific problems, multivariable adjusted hazard ratios (95% confidence interval) for mortality were 1.26 (1.19 to 1.32), 1.40 (1.33 to 1.48), and 1.66 (1.57 to 1.76) for 2, 3, and 4-6 nondisease-specific problems, respectively. Among those who survived, 37.1% required LTC; of those remaining who did not require LTC, 74.7% had functional impairment. A higher likelihood of transition to LTC (among those who survived 6 months) and functional impairment (among those who survived and did not require LTC) was seen with a higher number of problems. Identifying nondisease-specific problems may help patients and families anticipate LTC needs and functional impairment after dialysis initiation. Copyright © 2016 by the American Society of Nephrology.
CONSORT-EHEALTH: Improving and Standardizing Evaluation Reports of Web-based and Mobile Health Interventions

PubMed Central

2011-01-01

Background Web-based and mobile health interventions (also called “Internet interventions” or "eHealth/mHealth interventions") are tools or treatments, typically behaviorally based, that are operationalized and transformed for delivery via the Internet or mobile platforms. These include electronic tools for patients, informal caregivers, healthy consumers, and health care providers. The Consolidated Standards of Reporting Trials (CONSORT) statement was developed to improve the suboptimal reporting of randomized controlled trials (RCTs). While the CONSORT statement can be applied to provide broad guidance on how eHealth and mHealth trials should be reported, RCTs of web-based interventions pose very specific issues and challenges, in particular related to reporting sufficient details of the intervention to allow replication and theory-building. Objective To develop a checklist, dubbed CONSORT-EHEALTH (Consolidated Standards of Reporting Trials of Electronic and Mobile HEalth Applications and onLine TeleHealth), as an extension of the CONSORT statement that provides guidance for authors of eHealth and mHealth interventions. Methods A literature review was conducted, followed by a survey among eHealth experts and a workshop. Results A checklist instrument was constructed as an extension of the CONSORT statement. The instrument has been adopted by the Journal of Medical Internet Research (JMIR) and authors of eHealth RCTs are required to submit an electronic checklist explaining how they addressed each subitem. Conclusions CONSORT-EHEALTH has the potential to improve reporting and provides a basis for evaluating the validity and applicability of eHealth trials. Subitems describing how the intervention should be reported can also be used for non-RCT evaluation reports. As part of the development process, an evaluation component is essential; therefore, feedback from authors will be solicited, and a before-after study will evaluate whether reporting has been improved. PMID:22209829
Electron confinement at diffuse ZnMgO/ZnO interfaces

NASA Astrophysics Data System (ADS)

Coke, Maddison L.; Kennedy, Oscar W.; Sagar, James T.; Warburton, Paul A.

2017-01-01

Abrupt interfaces between ZnMgO and ZnO are strained due to lattice mismatch. This strain is relaxed if there is a gradual incorporation of Mg during growth, resulting in a diffuse interface. This strain relaxation is however accompanied by reduced confinement and enhanced Mg-ion scattering of the confined electrons at the interface. Here we experimentally study the electronic transport properties of the diffuse heteroepitaxial interface between single-crystal ZnO and ZnMgO films grown by molecular-beam epitaxy. The spatial extent of the interface region is controlled during growth by varying the zinc flux. We show that, as the spatial extent of the graded interface is reduced, the enhancement of electron mobility due to electron confinement more than compensates for any suppression of mobility due to increased strain. Furthermore, we determine the extent to which scattering of impurities in the ZnO substrate limits the electron mobility in diffuse ZnMgO-ZnO interfaces.
Developmental timing of housing mobility: longitudinal effects on externalizing behaviors among at-risk youth.

PubMed

Fowler, Patrick J; Henry, David B; Schoeny, Michael; Taylor, Jeremy; Chavira, Dina

2014-02-01

This longitudinal study tested whether developmental timing of exposure to housing mobility exacerbates behavior problems in an at-risk sample of youth. Participants were 2,442 youth 4 to 16 years old at risk for child maltreatment followed at 3 time points over a 36-month follow-up. Caregivers reported on youth externalizing behaviors at each assessment. Latent growth models examined the effect of housing mobility on behavior problems after accounting for change in cognitive development, family instability, child gender, ethnicity, family income, and caregiver mental health at baseline. Findings suggested increased housing mobility predicted greater behavior problems when children were exposed at key developmental periods. Preschoolers exhibited significantly higher rates of behavior problems that remained stable across the 3-year follow-up. Likewise, adolescents exposed to more mobility became relatively more disruptive over time. No effects were found for school-age children. Children who moved frequently during infancy and more recently demonstrated significantly worse behavior over time. The developmental timing of housing mobility affects child behavioral outcomes. Youth in developmental transition at the time of mobility are at greatest risk for disturbances to residential contexts. Assessing housing history represents an important component of interventions with at-risk families. Copyright © 2014 American Academy of Child and Adolescent Psychiatry. Published by Elsevier Inc. All rights reserved.
Application of microlearning technique and Twitter for educational purposes

NASA Astrophysics Data System (ADS)

Aitchanov, B. H.; Satabaldiyev, A. B.; Latuta, K. N.

2013-04-01

The current paper reviews the usage of social resource such as Twitter in microlearning technique for educational purposes. The problem is that most of instructors are unaware that with the help of social networks the students' productivity can increase. The research is applied on CS205 Advanced Programming in C++ course at Suleyman Demirel University (Kazakhstan). The collected results show that in a modern world of emerging mobile technologies, we are as educators should improve the way of teaching by adding electronically supported learning methods. In this study, the significance of microlearning technique is proposed.
The influence of surfaces on the transient terahertz conductivity and electron mobility of GaAs nanowires

NASA Astrophysics Data System (ADS)

Joyce, Hannah J.; Baig, Sarwat A.; Parkinson, Patrick; Davies, Christopher L.; Boland, Jessica L.; Tan, H. Hoe; Jagadish, Chennupati; Herz, Laura M.; Johnston, Michael B.

2017-06-01

Bare unpassivated GaAs nanowires feature relatively high electron mobilities (400-2100 cm2 V-1 s-1) and ultrashort charge carrier lifetimes (1-5 ps) at room temperature. These two properties are highly desirable for high speed optoelectronic devices, including photoreceivers, modulators and switches operating at microwave and terahertz frequencies. When engineering these GaAs nanowire-based devices, it is important to have a quantitative understanding of how the charge carrier mobility and lifetime can be tuned. Here we use optical-pump-terahertz-probe spectroscopy to quantify how mobility and lifetime depend on the nanowire surfaces and on carrier density in unpassivated GaAs nanowires. We also present two alternative frameworks for the analysis of nanowire photoconductivity: one based on plasmon resonance and the other based on Maxwell-Garnett effective medium theory with the nanowires modelled as prolate ellipsoids. We find the electron mobility decreases significantly with decreasing nanowire diameter, as charge carriers experience increased scattering at nanowire surfaces. Reducing the diameter from 50 nm to 30 nm degrades the electron mobility by up to 47%. Photoconductivity dynamics were dominated by trapping at saturable states existing at the nanowire surface, and the trapping rate was highest for the nanowires of narrowest diameter. The maximum surface recombination velocity, which occurs in the limit of all traps being empty, was calculated as 1.3 × 106 cm s-1. We note that when selecting the optimum nanowire diameter for an ultrafast device, there is a trade-off between achieving a short lifetime and a high carrier mobility. To achieve high speed GaAs nanowire devices featuring the highest charge carrier mobilities and shortest lifetimes, we recommend operating the devices at low charge carrier densities.
Localization-delocalization transition of electrons at the percolation threshold of semiconductor GaAs1-xNx alloys: The appearance of a mobility edge

NASA Astrophysics Data System (ADS)

Alberi, K.; Fluegel, B.; Beaton, D. A.; Ptak, A. J.; Mascarenhas, A.

2012-07-01

Electrons in semiconductor alloys have generally been described in terms of Bloch states that evolve from constructive interference of electron waves scattering from perfectly periodic potentials, despite the loss of structural periodicity that occurs on alloying. Using the semiconductor alloy GaAs1-xNx as a prototype, we demonstrate a localized to delocalized transition of the electronic states at a percolation threshold, the emergence of a mobility edge, and the onset of an abrupt perturbation to the host GaAs electronic structure, shedding light on the evolution of electronic structure in these abnormal alloys.
[Morphological structure of rat epiphysis exposed to electromagnetic radiation from communication devices].

PubMed

Yashchenko, S G; Rybalko, S Yu

Pineal gland is one of the most important components of homeostasis - the supporting system of the body. It participates in the launch of stress responses, restriction of their development, prevention of adverse effects on the body. There was proved an impact of electromagnetic radiation on the epiphysis. However, morphological changes in the epiphysis under exposure to electromagnetic radiation of modern communication devices are studied not sufficiently. For the time present the population is daily exposed to electromagnetic radiation, including local irradiation on the brain. These date determined the task of this research - the study of the structure of rat pineal gland under the exposure to electromagnetic radiation from personal computers and mobile phones. These date determined the task of this research - the study of the structure of rat pineal gland under the exposure to electromagnetic radiation from personal computers and mobile phones. Performed transmission electron microscopy revealed signs of degeneration of dark and light pinealocytes. These signs were manifested in the development of a complex of general and specific morphological changes. There was revealed the appearance of signs of aging and depletion transmission electron microscopy both in light and dark pinealocytes. These signs were manifested in the accumulation of lipofuscin granules and electron-dense "brain sand", the disappearance of nucleoli, cytoplasm vacuolization and mitochondrial cristae enlightenment.
Direct observation of 0.57 eV trap-related RF output power reduction in AlGaN/GaN high electron mobility transistors

NASA Astrophysics Data System (ADS)

Arehart, A. R.; Sasikumar, A.; Rajan, S.; Via, G. D.; Poling, B.; Winningham, B.; Heller, E. R.; Brown, D.; Pei, Y.; Recht, F.; Mishra, U. K.; Ringel, S. A.

2013-02-01

This paper reports direct evidence for trap-related RF output power loss in GaN high electron mobility transistors (HEMTs) grown by metal organic chemical vapor deposition (MOCVD) through increased concentration of a specific electron trap at EC-0.57 eV that is located in the drain access region, as a function of accelerated life testing (ALT). The trap is detected by constant drain current deep level transient spectroscopy (CID-DLTS) and the CID-DLTS thermal emission time constant precisely matches the measured drain lag. Both drain lag and CID-DLTS measurements show this state to already exist in pre-stressed devices, which coupled with its strong increase in concentration as a function of stress in the absence of significant increases in concentrations of other detected traps, imply its role in causing degradation, in particular knee walkout. This study reveals EC-0.57 eV trap concentration tracks degradation induced by ALT for MOCVD-grown HEMTs supplied by several commercial and university sources. The results suggest this defect has a common source and may be a key degradation pathway in AlGaN/GaN HEMTs and/or an indicator to predict device lifetime.
Mobile Abuse in University Students and profiles of victimization and aggression.

PubMed

Polo Del Río, Mª Isabel; Mendo Lázaro, Santiago; León Del Barco, Benito; Felipe Castaño, Elena

2017-09-29

The vast majority of young people have mobile phones. This has become a must-have item in their lives, with traditional socialization spaces displaced by virtual ones. They use their mobile phones for many hours a day, to the detriment of their psychological and social functioning, showing greater vulnerability to abusive or excessive use, and more likely to become problematic or addicted users. This paper aims to study the impact of mobile phone abuse in a sample of college students, assessing the social, personal, and communicational realms and deepening understanding of the different cyberbullying profiles, analyzing who has more personal and social problems using mobiles: victims or aggressors. Whether the number of hours of mobile phone use has an effect on these problems will also be explored. The sample (1,200 students) was selected by multistage cluster sampling among the faculties of the University of Extremadura. Data were obtained through Victimization (CYB-VIC) and Aggression (CYB-AGRES) through the mobile phone scales, and the Questionnaire of Experiences related to Mobile (CERM). The results show that mobile phone abuse generates conflicts in young people of both sexes, although girls have more communication and emotional problems than boys. In addition, age, field of knowledge, victim/aggressor profile, and hours of mobile phone use are crucial variables in the communication and emotional conflicts arising from the misuse of mobile.
Evaluation of Interference of Cellular Phones on Electronic Apex Locators: An In Vitro Study.

PubMed

Sidhu, Preena; Shankargouda, Swapnil; Dicksit, Daniel DevaPrakash; Mahdey, Haydar Majeed; Muzaffar, Danish; Arora, Shelly

2016-04-01

Use of mobile phone has been prohibited in many hospitals to prevent interference with medical devices. Electromagnetic radiation emitted from cellular phones might interfere with electronic working length determination. The purpose of this in vitro study was to evaluate the effect of a smart phone (Samsung Galaxy Note Edge) on working length determination of electronic apex locators (EALs) Propex II and Rootor. Fifteen intact, non-carious single-rooted teeth were decoronated at the cementoenamel junction. Visually, working length was determined by using a #15 K-file under stereomicroscope (×20). The effect of cellular phones on electronic working length (EWL) was determined under 2 experimental settings: (1) in a closed room with poor signal strength and (2) in a polyclinic set up with good signal strength and 5 conditions: (1) electronically, without cellular phone in room; (2) electronically, with cellular phone in physical contact with EAL; (3) electronically, with mobile phone in physical contact with EAL and in calling mode for a period of 25 seconds; (4) electronically, mobile phone placed at a distance of 40 cm from the EAL; and (5) electronically, mobile phone placed at a distance of 40 cm and in calling mode for a period of 25 seconds. The EWL was measured 3 times per tooth under each condition. Stability of the readings was scored from 1 to 3: (1) good stability, (2) stable reading after 1 attempt, and (3) stable reading after 2 attempts. The data were compared by using analysis of variance. The EWL measurements were not influenced by the presence of cellular phone and could be determined under all experimental conditions. Within the limitations of this study, it can be concluded that mobile phones do not interfere with the EWL determination. Copyright © 2016 American Association of Endodontists. Published by Elsevier Inc. All rights reserved.
Rational design of metal-organic electronic devices: A computational perspective

NASA Astrophysics Data System (ADS)

Chilukuri, Bhaskar

Organic and organometallic electronic materials continue to attract considerable attention among researchers due to their cost effectiveness, high flexibility, low temperature processing conditions and the continuous emergence of new semiconducting materials with tailored electronic properties. In addition, organic semiconductors can be used in a variety of important technological devices such as solar cells, field-effect transistors (FETs), flash memory, radio frequency identification (RFID) tags, light emitting diodes (LEDs), etc. However, organic materials have thus far not achieved the reliability and carrier mobility obtainable with inorganic silicon-based devices. Hence, there is a need for finding alternative electronic materials other than organic semiconductors to overcome the problems of inferior stability and performance. In this dissertation, I research the development of new transition metal based electronic materials which due to the presence of metal-metal, metal-pi, and pi-pi interactions may give rise to superior electronic and chemical properties versus their organic counterparts. Specifically, I performed computational modeling studies on platinum based charge transfer complexes and d 10 cyclo-[M(mu-L)]3 trimers (M = Ag, Au and L = monoanionic bidentate bridging (C/N~C/N) ligand). The research done is aimed to guide experimental chemists to make rational choices of metals, ligands, substituents in synthesizing novel organometallic electronic materials. Furthermore, the calculations presented here propose novel ways to tune the geometric, electronic, spectroscopic, and conduction properties in semiconducting materials. In addition to novel material development, electronic device performance can be improved by making a judicious choice of device components. I have studied the interfaces of a p-type metal-organic semiconductor viz cyclo-[Au(mu-Pz)] 3 trimer with metal electrodes at atomic and surface levels. This work was aimed to guide the device engineers to choose the appropriate metal electrodes considering the chemical interactions at the interface. Additionally, the calculations performed on the interfaces provided valuable insight into binding energies, charge redistribution, change in the energy levels, dipole formation, etc., which are important parameters to consider while fabricating an electronic device. The research described in this dissertation highlights the application of unique computational modeling methods at different levels of theory to guide the experimental chemists and device engineers toward a rational design of transition metal based electronic devices with low cost and high performance.
Hierarchical Bayesian modelling of mobility metrics for hazard model input calibration

NASA Astrophysics Data System (ADS)

Calder, Eliza; Ogburn, Sarah; Spiller, Elaine; Rutarindwa, Regis; Berger, Jim

2015-04-01

In this work we present a method to constrain flow mobility input parameters for pyroclastic flow models using hierarchical Bayes modeling of standard mobility metrics such as H/L and flow volume etc. The advantage of hierarchical modeling is that it can leverage the information in global dataset for a particular mobility metric in order to reduce the uncertainty in modeling of an individual volcano, especially important where individual volcanoes have only sparse datasets. We use compiled pyroclastic flow runout data from Colima, Merapi, Soufriere Hills, Unzen and Semeru volcanoes, presented in an open-source database FlowDat (https://vhub.org/groups/massflowdatabase). While the exact relationship between flow volume and friction varies somewhat between volcanoes, dome collapse flows originating from the same volcano exhibit similar mobility relationships. Instead of fitting separate regression models for each volcano dataset, we use a variation of the hierarchical linear model (Kass and Steffey, 1989). The model presents a hierarchical structure with two levels; all dome collapse flows and dome collapse flows at specific volcanoes. The hierarchical model allows us to assume that the flows at specific volcanoes share a common distribution of regression slopes, then solves for that distribution. We present comparisons of the 95% confidence intervals on the individual regression lines for the data set from each volcano as well as those obtained from the hierarchical model. The results clearly demonstrate the advantage of considering global datasets using this technique. The technique developed is demonstrated here for mobility metrics, but can be applied to many other global datasets of volcanic parameters. In particular, such methods can provide a means to better contain parameters for volcanoes for which we only have sparse data, a ubiquitous problem in volcanology.

Specific absorption rate variation in a brain phantom due to exposure by a 3G mobile phone: problems in dosimetry.

PubMed

Behari, J; Nirala, Jay Prakash

2013-12-01

A specific absorption rate (SAR) measurements system has been developed for compliance testing of personal mobile phone in a brain phantom material contained in a Perspex box. The volume of the box has been chosen corresponding to the volume of a small rat and illuminated by a 3G mobile phone frequency (1718.5 MHz), and the emitted radiation directed toward brain phantom .The induced fields in the phantom material are measured. Set up to lift the plane carrying the mobile phone is run by a pulley whose motion is controlled by a stepper motor. The platform is made to move at a pre-determined rate of 2 degrees per min limited up to 20 degrees. The measured data for induced fields in various locations are used to compute corresponding SAR values and inter comparison obtained. These data are also compared with those when the mobile phone is placed horizontally with respect to the position of the animal. The SAR data is also experimentally obtained by measuring a rise in temperature due to this mobile exposures and data compared with those obtained in the previous set. To seek a comparison with the safety criteria same set of measurements are performed in 10 g phantom material contained in a cubical box. These results are higher than those obtained with the knowledge of induced field measurements. It is concluded that SAR values are sensitive to the angular position of the moving platform and are well below the safety criteria prescribed for human exposure. The data are suggestive of having a fresh look to understand the mode of electromagnetic field -bio interaction.
PONS - Mobility Assistance on Footpaths for Public Transportation.

PubMed

Koutny, Reinhard; Miesenberger, Klaus

2015-01-01

This paper presents an ongoing project targeting mobility support for users of public transportation including people with limited mobility. Existing approaches in this field mostly offer non-continuous guidance during the whole journey including multiple rides with different vehicles and footpaths in between at transfer points. Especially people with limited mobility, like people with disabilities and elderly people, or travelers who are not familiar with the specific route or transfer point, like tourists, often struggle with public transportation. They crave for a seamless approach covering all links of the mobility chain - the sequence of sections of the whole route - and providing comprehensive assistance throughout the whole journey. Previous projects and widespread experiences of project partners revealed that especially footpath sections are lacking proper support. In particular, the consortium identified three problem areas in existing approaches when dealing with footpath sections: (1) A lack of information, (2) a lack of orientation and (3) a lack of provision of services. In order to bridge (lat. PONS) these gaps in the mobility chain, new paradigms and technology concepts are developed to tackle the shortcomings on footpaths and combined in a toolkit to help developers of applications with focus on pedestrian navigation and public transport to improve their solutions with sustainable and state-of-the-art approaches.
Dependence of mobility on the electron concentration upon scattering at polar optical phonons in A{sup III}–N nitrides

DOE Office of Scientific and Technical Information (OSTI.GOV)

Borisenko, S. I., E-mail: sib@tpu.ru

2016-04-15

The dependence of the effective relaxation time on the electron concentration in A{sup III}–N nitrides in the case of electron scattering at polar longitudinal optical phonons is calculated by the marching method. The method takes into account the inelasticity of electron scattering at polar optical phonons for nitrides in the zinc-blende approximation. The calculations show a substantial increase in mobility in samples with a degenerate electron gas, if screening of the long-range potential of polar longitudinal optical phonons is taken into account.
Self-Healing Polymer Dielectric for a High Capacitance Gate Insulator.

PubMed

Ko, Jieun; Kim, Young-Jae; Kim, Youn Sang

2016-09-14

Self-healing materials are required for development of various flexible electronic devices to repair cracks and ruptures caused by repetitive bending or folding. Specifically, a self-healing dielectric layer has huge potential to achieve healing electronics without mechanical breakdown in flexible operations. Here, we developed a high performance self-healing dielectric layer with an ionic liquid and catechol-functionalized polymer which exhibited a self-healing ability for both bulk and film states under mild self-healing conditions at 55 °C for 30 min. Due to the sufficient ion mobility of the ionic liquid in the polymer matrix, it had a high capacitance value above 1 μF/cm(2) at 20 Hz. Moreover, zinc oxide (ZnO) thin-film transistors (TFTs) with a self-healing dielectric layer exhibited a high field-effect mobility of 16.1 ± 3.07 cm(2) V(-1) s(-1) at a gate bias of 3 V. Even after repetitive self-healing of the dielectric layer from mechanical breaking, the electrical performance of the TFTs was well-maintained.
Nonmonotonous electron mobility due to structurally induced resonant coupling of subband states in an asymmetric double quantum well

DOE Office of Scientific and Technical Information (OSTI.GOV)

Nayak, R. K.; Das, S.; Panda, A. K.

We show that sharp nonmonotic variation of low temperature electron mobility μ can be achieved in GaAs/Al{sub x}Ga{sub 1-x}As barrier delta-doped double quantum well structure due to quantum mechanical transfer of subband electron wave functions within the wells. We vary the potential profile of the coupled structure as a function of the doping concentration in order to bring the subbands into resonance such that the subband energy levels anticross and the eigen states of the coupled structure equally share both the wells thereby giving rise to a dip in mobility. When the wells are of equal widths, the dip inmore » mobility occurs under symmetric doping of the side barriers. In case of unequal well widths, the resonance can be obtained by suitable asymmetric variation of the doping concentrations. The dip in mobility becomes sharp and also the wavy nature of mobility takes a rectangular shape by increasing the barrier width. We show that the dip in mobility at resonance is governed by the interface roughness scattering through step like changes in the subband mobilities. It is also gratifying to show that the drop in mobility at the onset of occupation of second subband is substantially supressed through the quantum mechanical transfer of subband wave functions between the wells. Our results can be utilized for performance enhancement of coupled quantum well devices.« less
Using an improved association rules mining optimization algorithm in web-based mobile-learning system

NASA Astrophysics Data System (ADS)

Huang, Yin; Chen, Jianhua; Xiong, Shaojun

2009-07-01

Mobile-Learning (M-learning) makes many learners get the advantages of both traditional learning and E-learning. Currently, Web-based Mobile-Learning Systems have created many new ways and defined new relationships between educators and learners. Association rule mining is one of the most important fields in data mining and knowledge discovery in databases. Rules explosion is a serious problem which causes great concerns, as conventional mining algorithms often produce too many rules for decision makers to digest. Since Web-based Mobile-Learning System collects vast amounts of student profile data, data mining and knowledge discovery techniques can be applied to find interesting relationships between attributes of learners, assessments, the solution strategies adopted by learners and so on. Therefore ,this paper focus on a new data-mining algorithm, combined with the advantages of genetic algorithm and simulated annealing algorithm , called ARGSA(Association rules based on an improved Genetic Simulated Annealing Algorithm), to mine the association rules. This paper first takes advantage of the Parallel Genetic Algorithm and Simulated Algorithm designed specifically for discovering association rules. Moreover, the analysis and experiment are also made to show the proposed method is superior to the Apriori algorithm in this Mobile-Learning system.
Building an Electronic Handover Tool for Physicians Using a Collaborative Approach between Clinicians and the Development Team.

PubMed

Guilbeault, Peggy; Momtahan, Kathryn; Hudson, Jordan

2015-01-01

In an effort by The Ottawa Hospital (TOH) to become one of the top 10% performers in patient safety and quality of care, the hospital embarked on improving the communication process during handover between physicians by building an electronic handover tool. It is expected that this tool will decrease information loss during handover. The Information Systems (IS) department engaged a workgroup of physicians to become involved in defining requirements to build an electronic handover tool that suited their clinical handover needs. This group became ultimately responsible for defining the graphical user interface (GUI) and all functionality related to the tool. Prior to the pilot, the Information Systems team will run a usability testing session to ensure the application is user friendly and has met the goals and objectives of the workgroup. As a result, The Ottawa Hospital has developed a fully integrated electronic handover tool built on the Clinical Mobile Application (CMA) which allows clinicians to enter patient problems, notes and tasks available to all physicians to facilitate the handover process.
The surface charge of trypanosomatids.

PubMed

Souto-Padrón, Thaïs

2002-12-01

The surface charge of trypanosomatids was evaluated by means of the binding of cationic particles, as visualized by electron microscopy and by direct measurements of the electrophoretic mobility of cells. The results obtained indicate that most of the trypanosomatids exhibit a negatively charged surface whose value is species specific and varies according to the developmental stages. Sialic acids associated with glycoproteins, glycolipids and phosphate groups are the major components responsible for the net negative surface charge of the trypanosomatids.
Housing mobility and cognitive development: Change in verbal and nonverbal abilities.

PubMed

Fowler, Patrick J; McGrath, Lauren M; Henry, David B; Schoeny, Michael; Chavira, Dina; Taylor, Jeremy J; Day, Orin

2015-10-01

This study investigates the influence of housing instability on verbal and nonverbal cognitive development among at-risk children and adolescents involved in the child welfare system. Frequent residential changes threaten child mental health, especially among low-income families. Little is known regarding disruptions to cognitive growth, specifically the impact on verbal and nonverbal abilities. The study tests whether developmental timing of housing mobility affects cognitive development beyond individual and family risks. A nationally representative study of families (n=2,442) susceptible to housing and family instability tracked children and adolescents aged 4-14 years (M=8.95 years) over 36 months following investigation by the child welfare system. Youth completed standardized cognitive assessments while caregivers reported on behavior problems and family risk at three time points. Latent growth models examined change in cognitive abilities over time. Housing mobility in the 12 months prior to baseline predicts lower verbal cognitive abilities that improve marginally. Similar effects emerge for all age groups; however, frequent moves in infancy diminish the influence of subsequent housing mobility on verbal tasks. Housing instability threatened cognitive development beyond child maltreatment, family changes, poverty, and other risks. Findings inform emerging research on environmental influences on neurocognitive development, as well as identify targets for early intervention. Systematic assessment of family housing problems, including through the child welfare system, provides opportunities for coordinated responses to prevent instability and cognitive threats. Copyright © 2015 Elsevier Ltd. All rights reserved.
A Study of the Impact of Mobile Phones as Learning Tools for Youth in Southern Baptist Churches

ERIC Educational Resources Information Center

Odom, Jerry David

2012-01-01

Problem: The problem of this study was to determine the differences between two groups of learners across four specified learner variables. The two groups were students using mobile phones and students without the use of mobile phones in youth Bible studies in selected Southern Baptist churches. The four learner variables were cognitive test…
Adjustable Trajectory Design Based on Node Density for Mobile Sink in WSNs

PubMed Central

Yang, Guisong; Liu, Shuai; He, Xingyu; Xiong, Naixue; Wu, Chunxue

2016-01-01

The design of movement trajectories for mobile sink plays an important role in data gathering for Wireless Sensor Networks (WSNs), as it affects the network coverage, and packet delivery ratio, as well as the network lifetime. In some scenarios, the whole network can be divided into subareas where the nodes are randomly deployed. The node densities of these subareas are quite different, which may result in a decreased packet delivery ratio and network lifetime if the movement trajectory of the mobile sink cannot adapt to these differences. To address these problems, we propose an adjustable trajectory design method based on node density for mobile sink in WSNs. The movement trajectory of the mobile sink in each subarea follows the Hilbert space-filling curve. Firstly, the trajectory is constructed based on network size. Secondly, the adjustable trajectory is established based on node density in specific subareas. Finally, the trajectories in each subarea are combined to acquire the whole network’s movement trajectory for the mobile sink. In addition, an adaptable power control scheme is designed to adjust nodes’ transmitting range dynamically according to the movement trajectory of the mobile sink in each subarea. The simulation results demonstrate that the proposed trajectories can adapt to network changes flexibly, thus outperform both in packet delivery ratio and in energy consumption the trajectories designed only based on the network size and the whole network node density. PMID:27941662
Synthesis, structural characterization and mobility measurement of electron accepting pyrazine derivatives

NASA Astrophysics Data System (ADS)

Lai, William W.

Several pyrazine based cyano aza derivatives have been synthesized and electronic devices made from them. Hole and electron mobilities were measured using a time of flight (TOF) method with silicon wafers as both the substrate and charge carrier generation layer. The high density of charge carriers generated from silicon allowed for film layers as thin as 100nm and up to 250nm. Two compounds, 2,3,6,7-tetracyano-1,4,5,8-tetraazanapthalene (TCNN) and 2,3,6,7-tetracyano-9,10-dioctyl-1,4,5,6,9,10-hexaazaanthracene (DOA) were shown to be good electron acceptors. The potentials at which TCNN and DOA are reduced was -0.03 and -1.5 volts respectively. Electron mobilities of both compounds were found to be 2x10-5 cm2V˙s . The previously unreported oxidation potential of 2,3,6,7-tetracyano-9,10-dioctyl 1,4,5,6,9,10-hexaazaanthracene was measured and the hole mobility was determined to be 2x10-5 cm2V˙s . In the case of DOA, the charge carrier density of the electron carriers was comparable to that of the charge carrier density of the hole carriers. In contrast, the electron TOF signal of TCNN, which does not exhibit an oxidation, is greater than the hole TOF signal by roughly 200 fold. The inability for TCNN to act as a hole carrier was remedied by combining it with tetrathiafulvalene (TTF) as an electron donor. Crystals of the 1:1 complex were grown and the solved structure revealed segregated stacking. Conductivity measurements, by both two and four point methods determined the range of conductivity ranging from 10-5 to 10-6 Scm . The electron and hole mobility of the material was determined to be 2x10-5 and 2x10-6 cm2V˙s respectively. With the complementary TTF:TCNN system, the electron V-s and hole TOF signals were comparable, indicating a material that can equally conduct electrons or holes.
Path planning and energy management of solar-powered unmanned ground vehicles

NASA Astrophysics Data System (ADS)

Kaplan, Adam

Many of the applications pertinent to unmanned vehicles, such as environmental research and analysis, communications, and information-surveillance and reconnaissance, benefit from prolonged vehicle operation time. Conventional efforts to increase the operational time of electric-powered unmanned vehicles have traditionally focused on the design of energy-efficient components and the identification of energy efficient search patterns, while little attention has been paid to the vehicle's mission-level path plan and power management. This thesis explores the formulation and generation of integrated motion-plans and power-schedules for solar-panel equipped mobile robots operating under strict energy constraints, which cannot be effectively addressed through conventional motion planning algorithms. Transit problems are considered to design time-optimal paths using both Balkcom-Mason and Pseudo-Dubins curves. Additionally, a more complicated problem to generate mission plans for vehicles which must persistently travel between certain locations, similar to the traveling salesperson problem (TSP), is presented. A comparison between one of the common motion-planning algorithms and experimental results of the prescribed algorithms, made possible by use of a test environment and mobile robot designed and developed specifically for this research, are presented and discussed.
Toward a North American Standard for Mobile Data Services

NASA Technical Reports Server (NTRS)

Dean, Richard A.; Levesque, Allen H.

1991-01-01

The rapid introduction of digital mobile communications systems is an important part of the emerging digital communications scene. These developments pose both a potential problem and a challenge. On one hand, these separate market driven developments can result in an uncontrolled mixture of analog and digital links which inhibit data modem services across the mobile/Public Switched network (PSTN). On the other hand, the near coincidence of schedules for development of some of these systems, i.e., Digital Cellular, Mobile Satellite, Land Mobile Radio, and ISDN, provides an opportunity to address interoperability problems by defining interfaces, control, and service standards that are compatible among these new services. In this paper we address the problem of providing data services interoperation between mobile terminals and data devices on the PSTN. The expected data services include G3 Fax, asynchronous data, and the government's STU-3 secure voice system, and future data services such as ISDN. We address a common architecture and a limited set of issues that are key to interoperable mobile data services. We believe that common mobile data standards will both improve the quality of data service and simplify the systems for manufacturers, data users, and service providers.
Toward a North American standard for mobile data services

NASA Astrophysics Data System (ADS)

Dean, Richard A.; Levesque, Allen H.

1991-09-01

The rapid introduction of digital mobile communications systems is an important part of the emerging digital communications scene. These developments pose both a potential problem and a challenge. On one hand, these separate market driven developments can result in an uncontrolled mixture of analog and digital links which inhibit data modem services across the mobile/Public Switched network (PSTN). On the other hand, the near coincidence of schedules for development of some of these systems, i.e., Digital Cellular, Mobile Satellite, Land Mobile Radio, and ISDN, provides an opportunity to address interoperability problems by defining interfaces, control, and service standards that are compatible among these new services. In this paper we address the problem of providing data services interoperation between mobile terminals and data devices on the PSTN. The expected data services include G3 Fax, asynchronous data, and the government's STU-3 secure voice system, and future data services such as ISDN. We address a common architecture and a limited set of issues that are key to interoperable mobile data services. We believe that common mobile data standards will both improve the quality of data service and simplify the systems for manufacturers, data users, and service providers.
Analytical Modeling of Acoustic Phonon-Limited Mobility in Strained Graphene Nanoribbons

NASA Astrophysics Data System (ADS)

Yousefvand, Ali; Ahmadi, Mohammad T.; Meshginqalam, Bahar

2017-11-01

Recent advances in graphene nanoribbon-based electronic devices encourage researchers to develop modeling and simulation methods to explore device physics. On the other hand, increasing the operating speed of nanoelectronic devices has recently attracted significant attention, and the modification of acoustic phonon interactions because of their important effect on carrier mobility can be considered as a method for carrier mobility optimization which subsequently enhances the device speed. Moreover, strain has an important influence on the electronic properties of the nanoelectronic devices. In this paper, the acoustic phonons mobility of armchair graphene nanoribbons ( n-AGNRs) under uniaxial strain is modeled analytically. In addition, strain, width and temperature effects on the acoustic phonon mobility of strained n-AGNRs are investigated. An increment in the strained AGNR acoustic phonon mobility by increasing the ribbon width is reported. Additionally, two different behaviors for the acoustic phonon mobility are verified by increasing the applied strain in 3 m, 3 m + 2 and 3 m + 1 AGNRs. Finally, the temperature effect on the modeled AGNR phonon mobility is explored, and mobility reduction by raising the temperature is reported.
Crystallographic analysis of the solid-state dewetting of polycrystalline gold film using automated indexing in a transmission electron microscope

DOE Office of Scientific and Technical Information (OSTI.GOV)

Jang, S. A.; Lee, H. J.; Oh, Y. J., E-mail: yjoh@hanbat.ac.kr

We analyzed the effect of crystallographic anisotropy on the morphological evolution of a 12-nm-thick gold film during solid-state dewetting at high temperatures using automated indexing tool in a transmission electron microscopy. Dewetting initiated at grain-boundary triple junctions adjacent to large grains resulting from abnormal grain growth driven by (111) texture development. Voids at the junctions developed shapes with faceted edges bounded by low-index crystal planes. The kinetic mobility of the edges varied with the crystal orientation normal to the edges, with a predominance of specific edges with the slowest retraction rates as the annealing time was increased.
Nanoparticle formation of deposited Agn-clusters on free-standing graphene

NASA Astrophysics Data System (ADS)

Al-Hada, M.; Peters, S.; Gregoratti, L.; Amati, M.; Sezen, H.; Parisse, P.; Selve, S.; Niermann, T.; Berger, D.; Neeb, M.; Eberhardt, W.

2017-11-01

Size-selected Agn-clusters on unsupported graphene of a commercial Quantifoil sample have been investigated by surface and element-specific techniques such as transmission electron microscopy (TEM), spatially-resolved inner-shell X-ray photoelectron spectroscopy (XPS) and Auger electron spectroscopy (AES). An agglomeration of the highly mobile clusters into nm-sized Ag-nanodots of 2-3 nm is observed. Moreover, crystalline as well as non-periodic fivefold symmetric structures of the Ag-nanoparticles are evident by high-resolution TEM. Using a lognormal size-distribution as revealed by TEM, the measured positive binding energy shift of the air-exposed Ag-nanodots can be explained by the size-dependent dynamical liquid-drop model.
Charge carrier mobility in conjugated organic polymers: simulation of an electron mobility in a carbazole-benzothiadiazole-based polymer

NASA Astrophysics Data System (ADS)

Li, Yaping; Lagowski, Jolanta B.

2011-08-01

Inorganic (mostly silicon based) solar cells are important devices that are used to solve the world energy and environmental needs. Now days, organic solar cells are attracting considerable attention in the field of photovoltaic cells because of their low cost and processing flexibility. Often conjugated polymers are used in the construction of the organic solar cells. We study the conjugated polymers' charge transport using computational approach that involves the use of the density functional theory (DFT), semiempirical (ZINDO), and Monte Carlo (MC) theoretical methods in order to determine their transfer integrals, reorganization energies, transfer rates (with the use of Marcus-Hush equation) and mobilities. We employ the experimentally determined three dimensional (3D) structure of poly(9,9'-di-n-octylfluorene-alt-benzothiadiazole) (F8BT) to estimate the electron mobility in a similar co-alternating polymer consisting of carbazole and benzothiadiazole units (C8BT). In agreement with our previous work, we found that including an orientational disorder in the crystal reduces the electron mobility in C8BT. We hope that the proposed computational approach can be used to predict charge mobility in organic materials that are used in solar cells.
Problem Solving and Collaboration Using Mobile Serious Games

ERIC Educational Resources Information Center

Sanchez, Jaime; Olivares, Ruby

2011-01-01

This paper presents the results obtained with the implementation of a series of learning activities based on Mobile Serious Games (MSGs) for the development of problem solving and collaborative skills in Chilean 8th grade students. Three MSGs were developed and played by teams of four students in order to solve problems collaboratively. A…

Mobile phone collection, reuse and recycling in the UK.

PubMed

Ongondo, F O; Williams, I D

2011-06-01

Mobile phones are the most ubiquitous electronic product on the globe. They have relatively short lifecycles and because of their (perceived) in-built obsolescence, discarded mobile phones represent a significant and growing problem with respect to waste electrical and electronic equipment (WEEE). An emerging and increasingly important issue for industry is the shortage of key metals, especially the types of metals found in mobile phones, and hence the primary aim of this timely study was to assess and evaluate the voluntary mobile phone takeback network in the UK. The study has characterised the information, product and incentives flows in the voluntary UK mobile phone takeback network and reviewed the merits and demerits of the incentives offered. A survey of the activities of the voluntary mobile phone takeback schemes was undertaken in 2008 to: identify and evaluate the takeback schemes operating in the UK; determine the target groups from whom handsets are collected; and assess the collection, promotion and advertising methods used by the schemes. In addition, the survey sought to identify and critically evaluate the incentives offered by the takeback schemes, evaluate their ease and convenience of use; and determine the types, qualities and quantities of mobile phones they collect. The study has established that the UK voluntary mobile phone takeback network can be characterised as three distinctive flows: information flow; product flow (handsets and related accessories); and incentives flow. Over 100 voluntary schemes offering online takeback of mobile phone handsets were identified. The schemes are operated by manufacturers, retailers, mobile phone network service operators, charities and by mobile phone reuse, recycling and refurbishing companies. The latter two scheme categories offer the highest level of convenience and ease of use to their customers. Approximately 83% of the schemes are either for-profit/commercial-oriented and/or operate to raise funds for charities. The voluntary schemes use various methods to collect mobile phones from consumers, including postal services, courier and in-store. The majority of schemes utilise and finance pre-paid postage to collect handsets. Incentives offered by the takeback schemes include monetary payments, donation to charity and entry into prize draws. Consumers from whom handsets and related equipment are collected include individuals, businesses, schools, colleges, universities, charities and clubs with some schemes specialising on collecting handsets from one target group. The majority (84.3%) of voluntary schemes did not provide information on their websites about the quantities of mobile phones they collect. The operations of UK takeback schemes are decentralised in nature. Comparisons are made between the UK's decentralised collection system versus Australia's centralised network for collection of mobile phones. The significant principal conclusions from the study are: there has been a significant rise in the number of takeback schemes operating in the UK since the initial scheme was launched in 1997; the majority of returned handsets seem to be of low quality; and there is very little available information on the quantities of mobile phones collected by the various schemes. Irrespective of their financial motives, UK takeback schemes increasingly play an important role in sustainable waste management by diverting EoL mobile phones from landfills and encouraging reuse and recycling. Recommendations for future actions to improve the management of end-of-life mobile phone handsets and related accessories are made. Copyright © 2011 Elsevier Ltd. All rights reserved.
Perspectives on the geographic stability and mobility of people in cities

PubMed Central

Hanson, Susan

2005-01-01

A class of questions in the human environment sciences focuses on the relationship between individual or household behavior and local geographic context. Central to these questions is the nature of people's geographic mobility as well as the duration of their locational stability at varying spatial and temporal scales. The problem for researchers is that the processes of mobility/stability are temporally and spatially dynamic and therefore difficult to measure. Whereas time and space are continuous, analysts must select levels of aggregation for both length of time in place and spatial scale of place that fit with the problem in question. Previous work has emphasized mobility and suppressed stability as an analytic category. I focus here on stability and show how analyzing individuals' stability requires also analyzing their mobility. Through an empirical example centered on the relationship between entrepreneurship and place, I demonstrate how a spotlight on stability illuminates a resolution to the measurement problem by highlighting the interdependence between the time and space dimensions of stability/mobility. PMID:16230616
A Case Study: Implementing an Interactive Video Instruction System in Teaching Electronics and Industrial Maintenance.

ERIC Educational Resources Information Center

Shipe, Ron; And Others

A study examined the development and implementation of an interactive video instruction system for teaching electronics and industrial maintenance at the University of Tennessee. The specific purposes of the study were to document unusual problems that may be encountered when this new technology is implemented, suggest corrective actions, and…
On-line and Mobil Learning Activities

NASA Astrophysics Data System (ADS)

Ackerman, S. A.; Whittaker, T. M.; Jasmin, T.; Mooney, M. E.

2012-12-01

Introductory college-level science courses for non-majors are critical gateways to imparting not only discipline-specific information, but also the basics of the scientific method and how science influences society. They are also indispensable for student success to degree. On-line, web-based homework (whether on computers or mobile devices) is a rapidly growing use of the Internet and is becoming a major component of instruction in science, replacing delayed feedback from a few major exams. Web delivery and grading of traditional textbook-type questions is equally effective as having students write them out for hand grading, as measured by student performance on conceptual and problem solving exams. During this presentation we will demonstrate some of the interactive on-line activities used to teach concepts and how scientists approach problem solving, and how these activities have impacted student learning. Evaluation of the activities, including formative and summative, will be discussed and provide evidence that these interactive activities significantly enhance understanding of introductory meteorological concepts in a college-level science course. More advanced interactive activities are also used in our courses for department majors, some of these will be discussed and demonstrated. Bring your mobile devices to play along! Here is an example on teaching contouring: http://profhorn.aos.wisc.edu/wxwise/contour/index.html
The Effect of Technological Devices on Cervical Lordosis

PubMed Central

Öğrenci, Ahmet; Koban, Orkun; Yaman, Onur; Dalbayrak, Sedat; Yılmaz, Mesut

2018-01-01

PURPOSE: There is a need for cervical flexion and even cervical hyperflexion for the use of technological devices, especially mobile phones. We investigated the effect of this use on the cervical lordosis angle. MATERIAL AND METHODS: A group of 156 patients who applied with only neck pain between 2013–2016 and had no additional problems were included. Patients are specifically questioned about mobile phone, tablet, and other devices usage. The value obtained by multiplying the year of usage and the average usage (hour) in daily life was determined as the total usage value (an average hour per day x year: hy). Cervical lordosis angles were statistically compared with the total time of use. RESULTS: In the general ROC analysis, the cut-off value was found to be 20.5 hy. When the cut-off value is tested, the overall accuracy is very good with 72.4%. The true estimate of true risk and non-risk is quite high. The ROC analysis is statistically significant. CONCLUSION: The use of computing devices, especially mobile telephones, and the increase in the flexion of the cervical spine indicate that cervical vertebral problems will increase even in younger people in future. Also, to using with attention at this point, ergonomic devices must also be developed. PMID:29610602
Staying connected: Service-specific orientation can be successfully achieved using a mobile application for onboarding care providers

PubMed Central

Chreiman, Kristen M; Prakash, Priya S; Kim, Patrick K; Mehta, Samir; McGinnis, Kelly; Gallagher, John J; Reilly, Patrick M

2017-01-01

Communicating service-specific practice patterns, guidelines, and provider information to a new team of learners that rotate frequently can be challenging. Leveraging individual and healthcare electronic resources, a mobile device platform was implemented into a newly revised resident onboarding process. We hypothesized that offering an easy-to-use mobile application would improve communication across multiple disciplines as well as improve provider experiences when transitioning to a new rotation. A mobile platform was created and deployed to assist with enhancing communication within a trauma service and its resident onboarding process. The platform had resource materials such as: divisional policies, Clinical Practice Guidelines (CMGs), and onboarding manuals along with allowing for the posting of divisional events, a divisional directory that linked to direct dialing, text or email messaging, as well as on-call schedules. A mixed-methods study, including an anonymous survey, aimed at providing information on team member's impressions and usage of the mobile application was performed. Usage statistics over a 3-month period were analyzed on those providers who completed the survey. After rotation on the trauma service, trainees were asked to complete an anonymous, online survey addressing both the experience with, as well as the utility of, the mobile app. Thirty of the 37 (81%) residents and medical students completed the survey. Twenty-five (83%) trainees stated that this was their first experience rotating on the trauma service and 6 (20%) were from outside of the health system. According to those surveyed, the most useful function of the app were access to the directory (15, 50%), the divisional calendar (4, 13.3%), and the on-call schedules (3, 10%). Overall, the app was felt to be easy to use (27, 90%) and was accessed an average of 7 times per day (1–50, SD 9.67). Over half the survey respondents felt that the mobile app was helpful in completing their everyday tasks (16, 53.3%). Fifteen (50%) of the respondents stated that the app made the transition to the trauma service easier. Twenty-five (83.3%) stated it was valuable knowing about departmental events and announcements, and 17 (56.7%) felt more connected to the division. The evolution of mobile technology is rapidly becoming fundamental in medical education and training. We found that integrating a service-specific mobile application improved the learner's experience when transitioning to a new service and was a valuable onboarding instrument. Level of evidence IV. PMID:29766089
Staying connected: Service-specific orientation can be successfully achieved using a mobile application for onboarding care providers.

PubMed

Chreiman, Kristen M; Prakash, Priya S; Martin, Niels D; Kim, Patrick K; Mehta, Samir; McGinnis, Kelly; Gallagher, John J; Reilly, Patrick M

2017-01-01

Communicating service-specific practice patterns, guidelines, and provider information to a new team of learners that rotate frequently can be challenging. Leveraging individual and healthcare electronic resources, a mobile device platform was implemented into a newly revised resident onboarding process. We hypothesized that offering an easy-to-use mobile application would improve communication across multiple disciplines as well as improve provider experiences when transitioning to a new rotation. A mobile platform was created and deployed to assist with enhancing communication within a trauma service and its resident onboarding process. The platform had resource materials such as: divisional policies, Clinical Practice Guidelines (CMGs), and onboarding manuals along with allowing for the posting of divisional events, a divisional directory that linked to direct dialing, text or email messaging, as well as on-call schedules. A mixed-methods study, including an anonymous survey, aimed at providing information on team member's impressions and usage of the mobile application was performed. Usage statistics over a 3-month period were analyzed on those providers who completed the survey. After rotation on the trauma service, trainees were asked to complete an anonymous, online survey addressing both the experience with, as well as the utility of, the mobile app. Thirty of the 37 (81%) residents and medical students completed the survey. Twenty-five (83%) trainees stated that this was their first experience rotating on the trauma service and 6 (20%) were from outside of the health system. According to those surveyed, the most useful function of the app were access to the directory (15, 50%), the divisional calendar (4, 13.3%), and the on-call schedules (3, 10%). Overall, the app was felt to be easy to use (27, 90%) and was accessed an average of 7 times per day (1-50, SD 9.67). Over half the survey respondents felt that the mobile app was helpful in completing their everyday tasks (16, 53.3%). Fifteen (50%) of the respondents stated that the app made the transition to the trauma service easier. Twenty-five (83.3%) stated it was valuable knowing about departmental events and announcements, and 17 (56.7%) felt more connected to the division. The evolution of mobile technology is rapidly becoming fundamental in medical education and training. We found that integrating a service-specific mobile application improved the learner's experience when transitioning to a new service and was a valuable onboarding instrument. Level of evidence IV.
Transport and breakdown analysis for improved figure-of-merit for AlGaN power devices

NASA Astrophysics Data System (ADS)

Coltrin, Michael E.; Kaplar, Robert J.

2017-02-01

Mobility and critical electric field for bulk AlxGa1-xN alloys across the full composition range (0 ≤ x ≤ 1) are analyzed to address the potential application of this material system for power electronics. Calculation of the temperature-dependent electron mobility includes the potential limitations due to different scattering mechanisms, including alloy, optical polar phonon, deformation potential, and piezoelectric scattering. The commonly used unipolar figure of merit (appropriate for vertical-device architectures), which increases strongly with increasing mobility and critical electric field, is examined across the alloy composition range to estimate the potential performance in power electronics applications. Alloy scattering is the dominant limitation to mobility and thus also for the unipolar figure of merit. However, at higher alloy compositions, the limitations due to alloy scattering are overcome by increased critical electric field. These trade-offs, and their temperature dependence, are quantified in the analysis.
Musculoskeletal impact of the use of various types of electronic devices on university students in Hong Kong: An evaluation by means of self-reported questionnaire.

PubMed

Woo, Eugenia H C; White, Peter; Lai, Christopher W K

2016-12-01

Despite the increasingly widespread popularity of electronic devices, there are limited comprehensive studies on the effects of usage and exposure to multiple electronic devices over extended periods of time. Therefore, this study explored the cumulative musculoskeletal implications of exposure to various electronic devices among university students. A self-reported questionnaire was administered in the university in Hong Kong and students provided information about the frequency and duration of electronic devices use, including computers, mobile phones and game consoles, and reported on any musculoskeletal pain or discomfort that may relate to electronic devices usage in the immediate 12 months prior to the survey date. A total of 503 university students (59% males and 41% females) aged 18-25 years completed the questionnaire. The results showed that 251 (49.9%) respondents reported upper limb musculoskeletal symptoms, particularly in the neck and shoulder regions. Among these, 155 (61.8%) indicated that their discomfort was related to electronic device usage. Statistically significant differences in exposure to electronic devices and musculoskeletal outcomes between genders were found (p < 0.05). The use of electronic devices and habitual postures were associated with musculoskeletal problems among university students in Hong Kong. This phenomenon highlights the urgent need for ergonomics education and recommendations to increase students' awareness of musculoskeletal wellbeing. Copyright © 2016 Elsevier Ltd. All rights reserved.
Ultra-low noise high electron mobility transistors for high-impedance and low-frequency deep cryogenic readout electronics

DOE Office of Scientific and Technical Information (OSTI.GOV)

Dong, Q.; Liang, Y. X.; Ferry, D.

2014-07-07

We report on the results obtained from specially designed high electron mobility transistors at 4.2 K: the gate leakage current can be limited lower than 1 aA, and the equivalent input noise-voltage and noise-current at 1 Hz can reach 6.3 nV/Hz{sup 1∕2} and 20 aA/Hz{sup 1∕2}, respectively. These results open the way to realize high performance low-frequency readout electronics under very low-temperature conditions.
A Planar Hall Thruster for Investigating Electron Mobility in ExB Devices (Preprint)

DTIC Science & Technology

2007-08-24

Hall thruster that emits and collects the Hall current across a planar discharge channel is described. The planar Hall thruster (PHT) is being investigated for use as a test bed to study electron mobility in ExB devices. The planar geometry attempts to de-couple the complex electron motion found in annular thrusters by using simplified geometry. During this initial test, the PHT was operated at discharge voltages between 50-150 V to verify operability and stability of the device. Hall current was emitted by hollow cathode electron sources and
Holographic particle detection

NASA Technical Reports Server (NTRS)

Bowen, Theodore

1988-01-01

The feasibility was studied of developing a novel particle track detector based on the detection of 1p-1s emission radiation from electron bubbles in liquid helium. The principles, design, construction, and initial testing of the detection system have been described in previous reports. The main obstacle encountered was the construction of the liquid-helium tight infrared windows. Despite numerous efforts in testing and redesigning the windows, the problem of window leakage at low temperature persisted. Due to limited time and resources, attention was switched to investigating the possibility of using room-temperature liquid as the detection medium. A possible mechanism was the detection of de-excitation radiation emitted from localized electrons in common liquids where electrons exhibit low mobilities, as suggested in the previous report. The purity of the liquid is critical in this method as the dissolved impurities (such as oxygen), even in trace amounts, will act as scavengers of electrons. Another mechanism is discussed whereby the formation of the superoxide ions by electron scavenging behavior of dissolved oxygen is exploited to detect the track of ionizing particles. An experiment to measure the ionization current produced in a liquid by a pulsed X-ray beam in order to study propertiies of the ions is also reported.
Chemoselective Hydrodehalogenation of Organic Halides Utilizing Two-Dimensional Anionic Electrons of Inorganic Electride [Ca2N]+·e^.

PubMed

Kim, Ye Ji; Kim, Sun Min; Yu, Chunghyeon; Yoo, YoungMin; Cho, Eun Jin; Yang, Jung Woon; Kim, Sung Wng

2017-01-31

Halogenated organic compounds are important anthropogenic chemicals widely used in chemical industry, biology, and pharmacology; however, the persistence and inertness of organic halides cause human health problems and considerable environmental pollution. Thus, the elimination or replacement of halogen atoms with organic halides has been considered a central task in synthetic chemistry. In dehalogenation reactions, the consecutive single-electron transfer from reducing agents generates the radical and corresponding carbanion and thus removes the halogen atom as the leaving group. Herein, we report a new strategy for an efficient chemoselective hydrodehalogenation through the formation of stable carbanion intermediates, which are simply achieved by using highly mobile two-dimensional electrons of inorganic electride [Ca 2 N] + ·e - with effective electron transfer ability. The consecutive single-electron transfer from inorganic electride [Ca 2 N] + ·e - stabilized free carbanions, which is a key step in achieving the selective reaction. Furthermore, a determinant more important than leaving group ability is the stability control of free carbanions according to the s character determined by the backbone structure. We anticipate that this approach may provide new insight into selective chemical formation, including hydrodehalogenation.
[Use of electronic media in adolescence. Results of the German Health Interview and Examination Survey for Children and Adolescents (KiGGS)].

PubMed

Lampert, T; Sygusch, R; Schlack, R

2007-01-01

The use of electronic media is playing an ever greater role in adolescents' recreational behaviour. From the point of view of the health sciences, one question which arises is the extent to which intensive media use is detrimental to physical activity and adolescents' health development. The data from the German Health Interview and Examination Survey for Children and Adolescents (KiGGS), which were evaluated with a focus on 11-17-year-olds, confirm this heavy use of electronic media. However, there are distinct group-specific differences. For example, boys spend more time than girls on computers, the internet and games consoles, whereas girls more often listen to music and use their mobile phones. Watching television and videos is equally popular among girls and boys. Adolescents of low social status or a low level of school education use electronic media far more frequently and for longer times, especially television and video, games consoles and mobile phones. The same is true of boys and girls from the former states of the GDR and for boys (but not girls) with a background of migration. A connection to physical activity has been established for adolescents who spend more than five hours a day using electronic media. Moreover, this group of heavy users is more often affected by adiposity. The results of the KiGGS study, which are in line with earlier research findings, thus demonstrate that the use of electronic media is also of relevance from the point of view of public health and should be included in investigations into the health of children and adolescents.
Field-induced strain degradation of AlGaN/GaN high electron mobility transistors on a nanometer scale

NASA Astrophysics Data System (ADS)

Lin, Chung-Han; Doutt, D. R.; Mishra, U. K.; Merz, T. A.; Brillson, L. J.

2010-11-01

Nanoscale Kelvin probe force microscopy and depth-resolved cathodoluminescence spectroscopy reveal an electronic defect evolution inside operating AlGaN/GaN high electron mobility transistors with degradation under electric-field-induced stress. Off-state electrical stress results in micron-scale areas within the extrinsic drain expanding and decreasing in electric potential, midgap defects increasing by orders-of-magnitude at the AlGaN layer, and local Fermi levels lowering as gate-drain voltages increase above a characteristic stress threshold. The pronounced onset of defect formation, Fermi level movement, and transistor degradation at the threshold gate-drain voltage of J. A. del Alamo and J. Joh [Microelectron. Reliab. 49, 1200 (2009)] is consistent with crystal deformation and supports the inverse piezoelectric model of high electron mobility transistor degradation.
Electron Mobilities and Effective Masses in InGaAs/InAlAs HEMT Structures with High In Content

NASA Astrophysics Data System (ADS)

Yuzeeva, N. A.; Sorokoumova, A. V.; Lunin, R. A.; Oveshnikov, L. N.; Galiev, G. B.; Klimov, E. A.; Lavruchin, D. V.; Kulbachinskii, V. A.

2016-12-01

InxGa_{1-{x}}As/InyAl_{1-{y}}As HEMT structures {δ}-doped by Si were grown by molecular beam epitaxy on InP substrate. We investigated the influence of the In content on the electron mobilities and effective masses in dimensionally quantized subbands. The electron effective masses were determined by the temperature dependence of the amplitude of the Shubnikov-de Haas effect at 1.6 and 4.2 K. We found that the more the In content in quantum well (QW), the less the electron effective masses. The mobilities are higher in HEMT structures with wider and deeper QW. The energy band diagrams were calculated by using Vegard's law for basic parameters. The calculated band diagrams are in a good agreement with the experimental data of photoluminescence spectra.
Mobile Phone Usage and its Health Effects Among Adults in a Semi-Urban Area of Southern India

PubMed Central

Abraham, Sherin Billy; Kanimozhy, K.; Prasad, R. Vishnu; Singh, Zile; Purty, Anil J.

2016-01-01

Introduction Worldwide, mobile phone usage has been increased dramatically which could affect the health of the people. India has the second largest number of mobile phone users. However there are only few studies conducted in India to assess its effects on health. Aim To determine the prevalence and pattern of mobile phone usage and to assess the relationship between certain selected health problems and mobile phone usage among adults. Settings and Design Community-based cross-sectional study was conducted in Kottakuppam, a town panchayat in Villupuram district of Coastal Tamil Nadu, Southern India. It is a semi-urban area with a population of about 16,000. Majority of the residents are Muslim by religion and belong to different socio economic status. Materials and Methods The study was approved by the Institutional Ethics Committee. A total of 2121 study participants were interviewed by the pre-final medical students through house-to-house survey using a pretested structured questionnaire. The questionnaire included the variables such as socio demographic profile, mobile phone usage and pattern, selected health problems, perceived benefits and threats and blood pressure. Selected health problems included headache, earache, neck pain, tinnitus, painful fingers, restlessness, morning tiredness, tingling fingers, fatigue, eye symptoms, sleep disturbance and hypertension. Statistical Analysis Used Only 2054 were included for data analysis using SPSS 17 version. Proportions were calculated. Chi-square test was used to measure the p-value. The p-value < 0.05 was considered as statistically significant. Results The prevalence of mobile phone usage was 70%. Calling facility (94.2%) was used more than the SMS (67.6%). Health problems like headache, earache, tinnitus, painful fingers and restlessness etc., were found to be positively associated with mobile phone usage. There was negative association between hypertension and mobile phone usage. Conclusion The prevalence of mobile phone usage was high. There was significant association between selected health problems and mobile phone usage. In future, higher studies are required to confirm our findings. PMID:26894095
A Mobile Learning Module for High School Fieldwork

ERIC Educational Resources Information Center

Hsu, Tzu-Yen; Chen, Che-Ming

2010-01-01

Although fieldwork is always cited as an important component of geographic education, there are many obstacles for executing high school fieldwork. Mobile electronic products are becoming popular and some schools are able to acquire these devices for mobile learning. This study attempts to provide a mobile-assisted means of guiding students…
Photocatalytic hydrogen generation enhanced by band gap narrowing and improved charge carrier mobility in AgTaO3 by compensated co-doping.

PubMed

Li, Min; Zhang, Junying; Dang, Wenqiang; Cushing, Scott K; Guo, Dong; Wu, Nianqiang; Yin, Penggang

2013-10-14

The correlation of the electronic band structure with the photocatalytic activity of AgTaO3 has been studied by simulation and experiments. Doping wide band gap oxide semiconductors usually introduces discrete mid-gap states, which extends the light absorption but has limited benefit for photocatalytic activity. Density functional theory (DFT) calculations show that compensated co-doping in AgTaO3 can overcome this problem by increasing the light absorption and simultaneously improving the charge carrier mobility. N/H and N/F co-doping can delocalize the discrete mid-gap states created by sole N doping in AgTaO3, which increases the band curvature and the electron-to-hole effective mass ratio. In particular, N/F co-doping creates a continuum of states that extend the valence band of AgTaO3. N/F co-doping thus improves the light absorption without creating the mid-gap states, maintaining the necessary redox potentials for water splitting and preventing from charge carrier trapping. The experimental results have confirmed that the N/F-codoped AgTaO3 exhibits a red-shift of the absorption edge in comparison with the undoped AgTaO3, leading to remarkable enhancement of photocatalytic activity toward hydrogen generation from water.
Mind Your Step: the Effects of Mobile Phone Use on Gaze Behavior in Stair Climbing.

PubMed

Ioannidou, Flora; Hermens, Frouke; Hodgson, Timothy L

2017-01-01

Stair walking is a hazardous activity and a common cause of fatal and non-fatal falls. Previous studies have assessed the role of eye movements in stair walking by asking people to repeatedly go up and down stairs in quiet and controlled conditions, while the role of peripheral vision was examined by giving participants specific fixation instructions or working memory tasks. We here extend this research to stair walking in a natural environment with other people present on the stairs and a now common secondary task: using one's mobile phone. Results show that using the mobile phone strongly draws one's attention away from the stairs, but that the distribution of gaze locations away from the phone is little influenced by using one's phone. Phone use also increased the time needed to walk the stairs, but handrail use remained low. These results indicate that limited foveal vision suffices for adequate stair walking in normal environments, but that mobile phone use has a strong influence on attention, which may pose problems when unexpected obstacles are encountered.

Distracted driving: mobile phone use while driving in three Mexican cities.

PubMed

Vera-López, Juan Daniel; Pérez-Núñez, Ricardo; Híjar, Martha; Hidalgo-Solórzano, Elisa; Lunnen, Jeffrey C; Chandran, Aruna; Hyder, Adnan A

2013-08-01

Mexico has a significant road traffic injury and mortality burden, and several states/municipalities have begun passing legislation restricting mobile phone use while driving (MPUWD). Little information is available about the prevalence of MPUWD in Mexico. This study measures the prevalence of mobile phone talking and texting among drivers in three cities, and identifies associated demographic and environmental factors. Two rounds of roadside observations from a group of randomly selected automobile drivers were conducted during 2011-2012 in Guadalajara-Zapopan, León and Cuernavaca. The overall prevalence of MPUWD was 10.78%; it was highest in Guadalajara-Zapopan (13.93%, 95% CI 12.87 to 15.05), lowest in Cuernavaca (7.42%, 95% CI 6.29 to 8.67), and remained stable over two rounds of observations, except for León, where the prevalence increased from 5.27% to 10.37% (p=0.000). Driving alone on major roads in non-taxi cars during the weekdays was associated with MPUWD. Results highlight the importance of studying the risk of mobile phone use, and designing and evaluating specific preventive interventions to address this problem in Mexico.
Aeronautical Mobile Airport Communications System (AeroMACS)

NASA Technical Reports Server (NTRS)

Budinger, James M.; Hall, Edward

2011-01-01

To help increase the capacity and efficiency of the nation s airports, a secure wideband wireless communications system is proposed for use on the airport surface. This paper provides an overview of the research and development process for the Aeronautical Mobile Airport Communications System (AeroMACS). AeroMACS is based on a specific commercial profile of the Institute of Electrical and Electronics Engineers (IEEE) 802.16 standard known as Wireless Worldwide Interoperability for Microwave Access or WiMAX (WiMax Forum). The paper includes background on the need for global interoperability in air/ground data communications, describes potential AeroMACS applications, addresses allocated frequency spectrum constraints, summarizes the international standardization process, and provides findings and recommendations from the world s first AeroMACS prototype implemented in Cleveland, Ohio, USA.
75 FR 4344 - Foreign-Trade Zone 22-Chicago, IL Application for Temporary/Interim Manufacturing Authority LG...

Federal Register 2010, 2011, 2012, 2013, 2014

2010-01-27

... DEPARTMENT OF COMMERCE Foreign-Trade Zones Board [Docket T-1-2010] Foreign-Trade Zone 22--Chicago, IL Application for Temporary/ Interim Manufacturing Authority LG Electronics MobileComm USA, Inc... Electronics MobileComm USA, Inc. (LGEMU) facility, located in Bolingbrook, Illinois. The application was filed...
77 FR 20847 - Certain Mobile Electronic Devices Incorporating Haptics; Institution of Investigation Pursuant to...

Federal Register 2010, 2011, 2012, 2013, 2014

2012-04-06

... INTERNATIONAL TRADE COMMISSION [Investigation No. 337-TA-834] Certain Mobile Electronic Devices Incorporating Haptics; Institution of Investigation Pursuant to 19 U.S.C. 1337 AGENCY: U.S. International Trade.... International Trade Commission on February 7, 2012, and an amended complaint was filed with the U.S...
Drift mobility of photo-electrons in organic molecular crystals: Quantitative comparison between theory and experiment

NASA Astrophysics Data System (ADS)

Reineker, P.; Kenkre, V. M.; Kühne, R.

1981-08-01

A quantitative comparison of a simple theoretical prediction for the drift mobility of photo-electrons in organic molecular crystals, calculated within the model of the coupled band-like and hopping motion, with experiments in napthalene of Schein et al. and Karl et al. is given.
76 FR 40930 - In the Matter of Certain Electronic Devices, Including Mobile Phones, Portable Music Players, and...

Federal Register 2010, 2011, 2012, 2013, 2014

2011-07-12

... INTERNATIONAL TRADE COMMISSION [Investigation No. 337-TA-701] In the Matter of Certain Electronic Devices, Including Mobile Phones, Portable Music Players, and Computers; Notice of Commission... music players, and computers by reason of infringement of various claims of United States Patent Nos. 6...
Travel in Adverse Weather Using Electronic Mobility Guidance Devices

ERIC Educational Resources Information Center

Farmer, Leicester W.

1975-01-01

After a discussion of the required characteristics of an ideal aid for blind individuals traveling in adverse weather, four electronic mobility guidance devices- the Mowat Sonar Sensor, the Russell E Model Pathsounder, the Bionic C-5 Laser Cane, and the Mark II Binaural Sensory Aid-are described in detail. (Author/SB)
Inventory of Electronic Mobility Aids for Persons with Visual Impairments: A Literature Review

ERIC Educational Resources Information Center

Roentgen, Uta R.; Gelderblom, Gert Jan; Soede, Mathijs; de Witte, Luc P.

2008-01-01

This literature review of existing electronic mobility aids for persons who are visually impaired and recent developments in this field identified and classified 146 products, systems, and devices. The 21 that are currently available that can be used without environmental adaptation are described in functional terms. (Contains 2 tables.)
Theoretical study of anisotropic mobility in ladder-type molecule organic semiconductors

NASA Astrophysics Data System (ADS)

Wei, Hui-Ling; Liu, Yu-Fang

2014-09-01

The properties of two ladder-type semiconductors {M1: 2,2'-(2,7-dihexy1-4,9-dihydro- s-indaceno[1,2- b:5,6- b']dithiophene-4,9-diylidene) dimalononitrile and M2: 2,7-dihexy1-4,9-dihydro- s-indaceno[1,2- b:5,6- b']dithiophene-4,9-dione} as the n-type and ambipolar organic materials are systematically investigated using the first-principle density functional theory combined with the Marcus-Hush electron transfer theory. It is found that the substitution of M1 induces large changes in its electron-transfer mobility of 1.370 cm2 V-1 s-1. M2 has both large electron- and hole-transfer mobility of 0.420 and 0.288 cm2 V-1 s-1, respectively, which indicates that M2 is potentially a high efficient ambipolar organic semiconducting material. Both the M1 and M2 crystals show remarkable anisotropic behavior. A proper design of the n-type and ambipolar organic electronic materials, which may have high mobility performance, is suggested based on the investigated two molecules.
A novel analytical model for scattering limited electron transport in nano-dimensional InAlAs/InGaAs heterostructure for cryogenic applications

NASA Astrophysics Data System (ADS)

Sharma, Neetika; Verma, Neha; Jogi, Jyotika

2017-11-01

This paper models the scattering limited electron transport in a nano-dimensional In0.52Al0.48As/In0.53Ga0.47As/InP heterostructure. An analytical model for temperature dependent sheet carrier concentration and carrier mobility in a two dimensional electron gas, confined in a triangular potential well has been developed. The model accounts for all the major scattering process including ionized impurity scattering and lattice scattering. Quantum mechanical variational technique is employed for studying the intrasubband scattering mechanism in the two dimensional electron gas. Results of various scattering limited structural parameters such as energy band-gap and functional parameters such as sheet carrier concentration, scattering rate and mobility are presented. The model corroborates the dominance of ionized impurity scattering mechanism at low temperatures and that of lattice scattering at high temperatures, both in turn limiting the carrier mobility. Net mobility obtained taking various scattering mechanisms into account has been found in agreement with earlier reported results, thus validating the model.
Study of electron mobility in small molecular SAlq by transient electroluminescence method

NASA Astrophysics Data System (ADS)

Kumar, Pankaj; Jain, S. C.; Kumar, Vikram; Chand, Suresh; Kamalasanan, M. N.; Tandon, R. P.

2007-12-01

The study of electron mobility of bis(2-methyl 8-hydroxyquinoline) (triphenyl siloxy) aluminium (SAlq) by transient electroluminescence (EL) is presented. An EL device is fabricated in bilayer, ITO/N,N'-diphenyl-N, N'-bis(3-methylphenyl)-(1,1'-biphenyl)-4,4'-diamine (TPD)/SAlq/LiF/Al configuration. The temporal evaluation of the EL with respect to the step voltage pulse is characterized by a delay time followed by a fast initial rise, which is followed by a slower rise. The delay time between the applied electrical pulse and the onset of EL is correlated with the carrier mobility (electron in our case). Transient EL studies for SAlq have been carried out at different temperatures and different applied electric fields. The electron mobility in SAlq is found to be field and temperature dependent and calculated to be 6.9 × 10-7 cm2 V-1 s-1 at 2.5 × 106 V cm-1 and 308 K. The EL decays immediately as the voltage is turned off and does not depend on the amplitude of the applied voltage pulse or dc offset.
Hybrid model for wireless mobility management using IPv6

NASA Astrophysics Data System (ADS)

Howie, Douglas P.; Sun, Junzhao; Koivisto, Antti T.

2001-07-01

Within the coming decade, there will be a dramatic increase in the availability of inexpensive, computationally powerful mobile devices running applications which use the Internet Protocol (IP) to access multimedia services over broad-band wireless connections. To this end, there has been extensive research and standardization in the areas of Mobile IP and IPv6. The purpose of this paper is to apply this work to the issues involved in designing a mobility model able to adapt to different wireless mobile IP scenarios. We describe the usefulness of this model in the 4th generation mobile multimedia systems to come. This new model has been synthesized through a comparative analysis of current mobile IP models where particular attention has been given to the problems of mobile IP handoff and mobility management and their impact on QoS. By applying a unique perspective to these problems, our model is used to set a roadmap for future mobile IPv6 testbed construction.
I2 basal stacking fault as a degradation mechanism in reverse gate-biased AlGaN/GaN HEMTs

NASA Astrophysics Data System (ADS)

Lang, A. C.; Hart, J. L.; Wen, J. G.; Miller, D. J.; Meyer, D. J.; Taheri, M. L.

2016-09-01

Here, we present the observation of a bias-induced, degradation-enhancing defect process in plasma-assisted molecular beam epitaxy grown reverse gate-biased AlGaN/GaN high electron mobility transistors (HEMTs), which is compatible with the current theoretical framework of HEMT degradation. Specifically, we utilize both conventional transmission electron microscopy and aberration-corrected transmission electron microscopy to analyze microstructural changes in not only high strained regions in degraded AlGaN/GaN HEMTs but also the extended gate-drain access region. We find a complex defect structure containing an I2 basal stacking fault and offer a potential mechanism for device degradation based on this defect structure. This work supports the reality of multiple failure mechanisms during device operation and identifies a defect potentially involved with device degradation.
Material electronic quality specifications for polycrystalline silicon wafers

NASA Astrophysics Data System (ADS)

Kalejs, J. P.

1994-06-01

As the use of polycrystalline silicon wafers has expanded in the photovoltaic industry, the need grows for monitoring and qualification techniques for as-grown material that can be used to optimize crystal growth and help predict solar cell performance. Particular needs are for obtaining quantitative measures over full wafer areas of the effects of lifetime limiting defects and of the lifetime upgrading taking place during solar cell processing. We review here the approaches being pursued in programs under way to develop material quality specifications for thin Edge-defined Film-fed Growth (EFG) polycrystalline silicon as-grown wafers. These studies involve collaborations between Mobil Solar, and NREL and university-based laboratories.
An Adaptive Clustering Approach Based on Minimum Travel Route Planning for Wireless Sensor Networks with a Mobile Sink.

PubMed

Tang, Jiqiang; Yang, Wu; Zhu, Lingyun; Wang, Dong; Feng, Xin

2017-04-26

In recent years, Wireless Sensor Networks with a Mobile Sink (WSN-MS) have been an active research topic due to the widespread use of mobile devices. However, how to get the balance between data delivery latency and energy consumption becomes a key issue of WSN-MS. In this paper, we study the clustering approach by jointly considering the Route planning for mobile sink and Clustering Problem (RCP) for static sensor nodes. We solve the RCP problem by using the minimum travel route clustering approach, which applies the minimum travel route of the mobile sink to guide the clustering process. We formulate the RCP problem as an Integer Non-Linear Programming (INLP) problem to shorten the travel route of the mobile sink under three constraints: the communication hops constraint, the travel route constraint and the loop avoidance constraint. We then propose an Imprecise Induction Algorithm (IIA) based on the property that the solution with a small hop count is more feasible than that with a large hop count. The IIA algorithm includes three processes: initializing travel route planning with a Traveling Salesman Problem (TSP) algorithm, transforming the cluster head to a cluster member and transforming the cluster member to a cluster head. Extensive experimental results show that the IIA algorithm could automatically adjust cluster heads according to the maximum hops parameter and plan a shorter travel route for the mobile sink. Compared with the Shortest Path Tree-based Data-Gathering Algorithm (SPT-DGA), the IIA algorithm has the characteristics of shorter route length, smaller cluster head count and faster convergence rate.
Diazonium functionalized graphene: microstructure, electric, and magnetic properties.

PubMed

Huang, Ping; Jing, Long; Zhu, Huarui; Gao, Xueyun

2013-01-15

The unique honeycomb lattice structure of graphene gives rise to its outstanding electronic properties such as ultrahigh carrier mobility, ballistic transport, and more. However, a crucial obstacle to its use in the electronics industry is its lack of an energy bandgap. A covalent chemistry strategy could overcome this problem, and would have the benefits of being highly controllable and stable in the ambient environment. One possible approach is aryl diazonium functionalization. In this Account, we investigate the micromolecular/lattice structure, electronic structure, and electron-transport properties of nitrophenyl-diazonium-functionalized graphene. We find that nitrophenyl groups mainly adopt random and inhomogeneous configurations on the graphene basal plane, and that their bonding with graphene carbon atoms leads to slight elongation of the graphene lattice spacing. By contrast, hydrogenated graphene has a compressed lattice. Low levels of functionalization suppressed the electric conductivity of the resulting functionalized graphene, while highly functionalized graphene showed the opposite effect. This difference arises from the competition between the charge transfer effect and the scattering enhancement effect introduced by nitrophenyl groups bonding with graphene carbon atoms. Detailed electron transport measurements revealed that the nitrophenyl diazonium functionalization locally breaks the symmetry of graphene lattice, which leads to an increase in the density of state near the Fermi level, thus increasing the carrier density. On the other hand, the bonded nitrophenyl groups act as scattering centers, lowering the mean free path of the charge carriers and suppressing the carrier mobility. In rare cases, we observed ordered configurations of nitrophenyl groups in local domains on graphene flakes due to fluctuations in the reaction processes. We describe one example of such a superlattice, with a lattice constant nearly twice of that of pristine graphene. We performed comprehensive theoretical calculations to investigate the lattice and the electronic structure of the superlattice structure. Our results reveal that it is a thermodynamically stable, spin-polarized semiconductor with a bandgap of ∼0.5 eV. Our results demonstrate the possibility of controlling graphene's electronic properties using aryl diazonium functionalization. Asymmetric addition of aryl groups to different sublattices of graphene is a promising approach for producing ferromagnetic, semiconductive graphene, which will have broad applications in the electronic industry.
Electrorecycling of Critical and Value Metals from Mobile Electronics

DOE Office of Scientific and Technical Information (OSTI.GOV)

Tedd E. Lister; Peming Wang; Andre Anderko

2014-09-01

Mobile electronic devices such as smart phones and tablets are a significant source of valuable metals that should be recycled. Each year over a billion devices are sold world-wide and the average life is only a couple years. Value metals in phones are gold, palladium, silver, copper, cobalt and nickel. Devices now contain increasing amounts of rare earth elements (REE). In recent years the supply chain for REE has moved almost exclusively to China. They are contained in displays, speakers and vibrators within the devices. By US Department of Energy (DOE) classification, specific REEs (Nd, Dy, Eu, Tb and Y)more » are considered critical while others (Ce, La and Pr) are deemed near critical. Effective recycling schemes should include the recovery of these critical materials. By including more value materials in a recovery scheme, more value can be obtained by product diversification and less waste metals remains to be disposed of. REEs are mined as a group such that when specific elements become critical significantly more ore must be processed to capture the dilute but valuable critical elements. Targeted recycling of items containing the more of the less available critical materials could address their future criticality. This presentation will describe work in developing aqueous electrochemistry-based schemes for recycling metals from scrap mobile electronics. The electrorecycling process generates oxidizing agents at an anode while reducing dissolved metals at the cathode. E vs pH diagrams and metals dissolution experiments are used to assess effectiveness of various solution chemistries. Although several schemes were envisioned, a two stages process has been the focus of work: 1) initial dissolution of Cu, Sn, Ag and magnet materials using Fe+3 generated in acidic sulfate and 2) final dissolution of Pd and Au using Cl2 generated in an HCl solution. Experiments were performed using simulated metal mixtures. Both Cu and Ag were recovered at ~ 97% using Fe+3 while leaving Au and Ag intact. REE were extracted from the dissolved mixture using conventional methods. A discussion of future research directions will be discussed.« less
Influence of acceptor on charge mobility in stacked π-conjugated polymers

NASA Astrophysics Data System (ADS)

Sun, Shih-Jye; Menšík, Miroslav; Toman, Petr; Gagliardi, Alessio; Král, Karel

2018-02-01

We present a quantum molecular model to calculate mobility of π-stacked P3HT polymer layers with electron acceptor dopants coupled next to side groups in random position with respect to the linear chain. The hole density, the acceptor LUMO energy and the hybridization transfer integral between the acceptor and polymer were found to be very critical factors to the final hole mobility. For a dopant LUMO energy close and high above the top of the polymer valence band we have found a significant mobility increase with the hole concentration and with the dopant LUMO energy approaching the top of the polymer valence band. Higher mobility was achieved for small values of hybridization transfer integral between polymer and the acceptor, corresponding to the case of weakly bound acceptor. Strong couplings between the polymer and the acceptor with Coulomb repulsion interactions induced from the electron localizations was found to suppress the hole mobility.
A Study on Mobile Learning as a Learning Style in Modern Research Practice

ERIC Educational Resources Information Center

Joan, D. R. Robert

2013-01-01

Mobile learning is a kind of learning that takes place via a portable handheld electronic device. It also refers to learning via other kinds of mobile devices such as tablet computers, net-books and digital readers. The objective of mobile learning is to provide the learner the ability to assimilate learning anywhere and at anytime. Mobile devices…
Localization-delocalization transition of electrons at the percolation threshold of semiconductor GaAs 1–xN x alloys: The appearance of a mobility edge

DOE PAGES

Alberi, K.; Fluegel, B.; Beaton, D. A.; ...

2012-07-09

Electrons in semiconductor alloys have generally been described in terms of Bloch states that evolve from constructive interference of electron waves scattering from perfectly periodic potentials, despite the loss of structural periodicity that occurs on alloying. Using the semiconductor alloy GaAs₁₋ xN x as a prototype, we demonstrate a localized to delocalized transition of the electronic states at a percolation threshold, the emergence of a mobility edge, and the onset of an abrupt perturbation to the host GaAs electronic structure, shedding light on the evolution of electronic structure in these abnormal alloys.

Suppressed carrier density for the patterned high mobility two-dimensional electron gas at γ-Al2O3/SrTiO3 heterointerfaces

NASA Astrophysics Data System (ADS)

Niu, Wei; Gan, Yulin; Zhang, Yu; Valbjørn Christensen, Dennis; von Soosten, Merlin; Wang, Xuefeng; Xu, Yongbing; Zhang, Rong; Pryds, Nini; Chen, Yunzhong

2017-07-01

The two-dimensional electron gas (2DEG) at the non-isostructural interface between spinel γ-Al2O3 and perovskite SrTiO3 is featured by a record electron mobility among complex oxide interfaces in addition to a high carrier density up to the order of 1015 cm-2. Herein, we report on the patterning of 2DEG at the γ-Al2O3/SrTiO3 interface grown at 650 °C by pulsed laser deposition using a hard mask of LaMnO3. The patterned 2DEG exhibits a critical thickness of 2 unit cells of γ-Al2O3 for the occurrence of interface conductivity, similar to the unpatterned sample. However, its maximum carrier density is found to be approximately 3 × 1013 cm-2, much lower than that of the unpatterned sample (˜1015 cm-2). Remarkably, a high electron mobility of approximately 3600 cm2 V-1 s-1 was obtained at low temperatures for the patterned 2DEG at a carrier density of ˜7 × 1012 cm-2, which exhibits clear Shubnikov-de Haas quantum oscillations. The patterned high-mobility 2DEG at the γ-Al2O3/SrTiO3 interface paves the way for the design and application of spinel/perovskite interfaces for high-mobility all-oxide electronic devices.
Electron tunneling spectroscopy study of electrically active traps in AlGaN/GaN high electron mobility transistors

DOE Office of Scientific and Technical Information (OSTI.GOV)

Yang, Jie, E-mail: jie.yang@yale.edu; Cui, Sharon; Ma, T. P.

2013-11-25

We investigate the energy levels of electron traps in AlGaN/GaN high electron mobility transistors by the use of electron tunneling spectroscopy. Detailed analysis of a typical spectrum, obtained in a wide gate bias range and with both bias polarities, suggests the existence of electron traps both in the bulk of AlGaN and at the AlGaN/GaN interface. The energy levels of the electron traps have been determined to lie within a 0.5 eV band below the conduction band minimum of AlGaN, and there is strong evidence suggesting that these traps contribute to Frenkel-Poole conduction through the AlGaN barrier.
High electron mobility and quantum oscillations in non-encapsulated ultrathin semiconducting Bi 2O 2Se

DOE Office of Scientific and Technical Information (OSTI.GOV)

Wu, Jinxiong; Yuan, Hongtao; Meng, Mengmeng

Identifying new two-dimensional (2D) materials with both high carrier mobility and a large electronic band gap is critical for novel electronics and optoelectronics applications. Here, we demonstrated a new air-stable ultrahigh-mobility layered Bi 2O 2Se semiconductor with a large band gap of ~ 0.8 eV and a low effective mass of ~ 0.14 m 0. High-quality 2D Bi2O2Se crystals with a thickness down to a monolayer and a domain size greater than 200 μm were readily grown by chemical vapor deposition (CVD). Size-tunable band gap of Bi 2O 2Se was found to increase as thinning down to the monolayer duemore » to the quantum confinement effect. An ultrahigh Hall mobility of > 20,000 cm 2 V -1 s -1 was achieved in as-grown Bi 2O 2Se flakes at 1.9 K, which allows for the observation of Shubnikov–de Haas quantum oscillations. Top-gated field-effect transistors based on CVD-grown 2D Bi 2O 2Se crystals (down to bilayer) exhibited high Hall mobility (up to 450 cm 2 V -1 s -1), large current on/off ratios (>106) and near-ideal subthreshold swings (~65 mV/dec) at room temperature. Our results make the high-mobility 2D Bi 2O 2Se semiconductor a promising candidate for future high-speed and low-power electronic applications.« less
High electron mobility and quantum oscillations in non-encapsulated ultrathin semiconducting Bi 2O 2Se

DOE PAGES

Wu, Jinxiong; Yuan, Hongtao; Meng, Mengmeng; ...

2017-04-03

Identifying new two-dimensional (2D) materials with both high carrier mobility and a large electronic band gap is critical for novel electronics and optoelectronics applications. Here, we demonstrated a new air-stable ultrahigh-mobility layered Bi 2O 2Se semiconductor with a large band gap of ~ 0.8 eV and a low effective mass of ~ 0.14 m 0. High-quality 2D Bi2O2Se crystals with a thickness down to a monolayer and a domain size greater than 200 μm were readily grown by chemical vapor deposition (CVD). Size-tunable band gap of Bi 2O 2Se was found to increase as thinning down to the monolayer duemore » to the quantum confinement effect. An ultrahigh Hall mobility of > 20,000 cm 2 V -1 s -1 was achieved in as-grown Bi 2O 2Se flakes at 1.9 K, which allows for the observation of Shubnikov–de Haas quantum oscillations. Top-gated field-effect transistors based on CVD-grown 2D Bi 2O 2Se crystals (down to bilayer) exhibited high Hall mobility (up to 450 cm 2 V -1 s -1), large current on/off ratios (>106) and near-ideal subthreshold swings (~65 mV/dec) at room temperature. Our results make the high-mobility 2D Bi 2O 2Se semiconductor a promising candidate for future high-speed and low-power electronic applications.« less
High Thermoelectric Power Factor of High-Mobility 2D Electron Gas.

PubMed

Ohta, Hiromichi; Kim, Sung Wng; Kaneki, Shota; Yamamoto, Atsushi; Hashizume, Tamotsu

2018-01-01

Thermoelectric conversion is an energy harvesting technology that directly converts waste heat from various sources into electricity by the Seebeck effect of thermoelectric materials with a large thermopower ( S ), high electrical conductivity (σ), and low thermal conductivity (κ). State-of-the-art nanostructuring techniques that significantly reduce κ have realized high-performance thermoelectric materials with a figure of merit ( ZT = S 2 ∙σ∙ T ∙κ -1 ) between 1.5 and 2. Although the power factor (PF = S 2 ∙σ) must also be enhanced to further improve ZT , the maximum PF remains near 1.5-4 mW m -1 K -2 due to the well-known trade-off relationship between S and σ. At a maximized PF, σ is much lower than the ideal value since impurity doping suppresses the carrier mobility. A metal-oxide-semiconductor high electron mobility transistor (MOS-HEMT) structure on an AlGaN/GaN heterostructure is prepared. Applying a gate electric field to the MOS-HEMT simultaneously modulates S and σ of the high-mobility electron gas from -490 µV K -1 and ≈10 -1 S cm -1 to -90 µV K -1 and ≈10 4 S cm -1 , while maintaining a high carrier mobility (≈1500 cm 2 V -1 s -1 ). The maximized PF of the high-mobility electron gas is ≈9 mW m -1 K -2 , which is a two- to sixfold increase compared to state-of-the-art practical thermoelectric materials.
High-mobility ambipolar ZnO-graphene hybrid thin film transistors.

PubMed

Song, Wooseok; Kwon, Soon Yeol; Myung, Sung; Jung, Min Wook; Kim, Seong Jun; Min, Bok Ki; Kang, Min-A; Kim, Sung Ho; Lim, Jongsun; An, Ki-Seok

2014-02-11

In order to combine advantages of ZnO thin film transistors (TFTs) with a high on-off ratio and graphene TFTs with extremely high carrier mobility, we present a facile methodology for fabricating ZnO thin film/graphene hybrid two-dimensional TFTs. Hybrid TFTs exhibited ambipolar behavior, an outstanding electron mobility of 329.7 ± 16.9 cm(2)/V·s, and a high on-off ratio of 10(5). The ambipolar behavior of the ZnO/graphene hybrid TFT with high electron mobility could be due to the superimposed density of states involving the donor states in the bandgap of ZnO thin films and the linear dispersion of monolayer graphene. We further established an applicable circuit model for understanding the improvement in carrier mobility of ZnO/graphene hybrid TFTs.
The role of regioregularity, crystallinity, and chain orientation on electron transport in a high-mobility n-type copolymer.

PubMed

Steyrleuthner, Robert; Di Pietro, Riccardo; Collins, Brian A; Polzer, Frank; Himmelberger, Scott; Schubert, Marcel; Chen, Zhihua; Zhang, Shiming; Salleo, Alberto; Ade, Harald; Facchetti, Antonio; Neher, Dieter

2014-03-19

We investigated the correlation between the polymer backbone structural regularity and the charge transport properties of poly{[N,N'-bis(2-octyldodecyl)-1,4,5,8-naphthalenediimide-2,6-diyl]-alt-5,5'-(2,2'-bithiophene)} [P(NDI2OD-T2)], a widely studied semiconducting polymer exhibiting high electron mobility and an unconventional micromorphology. To understand the influence of the chemical structure and crystal packing of conventional regioregular P(NDI2OD-T2) [RR-P(NDI2OD-T2)] on the charge transport, the corresponding regioirregular polymer RI-P(NDI2OD-T2) was synthesized. By combining optical, X-ray, and transmission electron microscopy data, we quantitatively characterized the aggregation, crystallization, and backbone orientation of all of the polymer films, which were then correlated to the electron mobilities in electron-only diodes. By carefully selecting the preparation conditions, we were able to obtain RR-P(NDI2OD-T2) films with similar crystalline structure along the three crystallographic axes but with different orientations of the polymer chains with respect to the substrate surface. RI-P(NDI2OD-T2), though exhibiting a rather similar LUMO structure and energy compared with the regioregular counterpart, displayed a very different packing structure characterized by the formation of ordered stacks along the lamellar direction without detectible π-stacking. Vertical electron mobilities were extracted from the space-charge-limited currents in unipolar devices. We demonstrate the anisotropy of the charge transport along the different crystallographic directions and how the mobility depends on π-stacking but is insensitive to the degree or coherence of lamellar stacking. The comparison between the regioregular and regioirregular polymers also shows how the use of large planar functional groups leads to improved charge transport, with mobilities that are less affected by chemical and structural disorder with respect to classic semicrystalline polymers such as poly(3-hexylthiophene).
Charge transport in organic molecular semiconductors from first principles: The bandlike hole mobility in a naphthalene crystal

NASA Astrophysics Data System (ADS)

Lee, Nien-En; Zhou, Jin-Jian; Agapito, Luis A.; Bernardi, Marco

2018-03-01

Predicting charge transport in organic molecular crystals is notoriously challenging. Carrier mobility calculations in organic semiconductors are dominated by quantum chemistry methods based on charge hopping, which are laborious and only moderately accurate. We compute from first principles the electron-phonon scattering and the phonon-limited hole mobility of naphthalene crystal in the framework of ab initio band theory. Our calculations combine GW electronic bandstructures, ab initio electron-phonon scattering, and the Boltzmann transport equation. The calculated hole mobility is in very good agreement with experiment between 100 -300 K , and we can predict its temperature dependence with high accuracy. We show that scattering between intermolecular phonons and holes regulates the mobility, though intramolecular phonons possess the strongest coupling with holes. We revisit the common belief that only rigid molecular motions affect carrier dynamics in organic molecular crystals. Our paper provides a quantitative and rigorous framework to compute charge transport in organic crystals and is a first step toward reconciling band theory and carrier hopping computational methods.
All-printed diode operating at 1.6 GHz

PubMed Central

Sani, Negar; Robertsson, Mats; Cooper, Philip; Wang, Xin; Svensson, Magnus; Andersson Ersman, Peter; Norberg, Petronella; Nilsson, Marie; Nilsson, David; Liu, Xianjie; Hesselbom, Hjalmar; Akesso, Laurent; Fahlman, Mats; Crispin, Xavier; Engquist, Isak; Berggren, Magnus; Gustafsson, Göran

2014-01-01

Printed electronics are considered for wireless electronic tags and sensors within the future Internet-of-things (IoT) concept. As a consequence of the low charge carrier mobility of present printable organic and inorganic semiconductors, the operational frequency of printed rectifiers is not high enough to enable direct communication and powering between mobile phones and printed e-tags. Here, we report an all-printed diode operating up to 1.6 GHz. The device, based on two stacked layers of Si and NbSi2 particles, is manufactured on a flexible substrate at low temperature and in ambient atmosphere. The high charge carrier mobility of the Si microparticles allows device operation to occur in the charge injection-limited regime. The asymmetry of the oxide layers in the resulting device stack leads to rectification of tunneling current. Printed diodes were combined with antennas and electrochromic displays to form an all-printed e-tag. The harvested signal from a Global System for Mobile Communications mobile phone was used to update the display. Our findings demonstrate a new communication pathway for printed electronics within IoT applications. PMID:25002504
Intrinsic Electron Mobility Exceeding 10³ cm²/(V s) in Multilayer InSe FETs.

PubMed

Sucharitakul, Sukrit; Goble, Nicholas J; Kumar, U Rajesh; Sankar, Raman; Bogorad, Zachary A; Chou, Fang-Cheng; Chen, Yit-Tsong; Gao, Xuan P A

2015-06-10

Graphene-like two-dimensional (2D) materials not only are interesting for their exotic electronic structure and fundamental electronic transport or optical properties but also hold promises for device miniaturization down to atomic thickness. As one material belonging to this category, InSe, a III-VI semiconductor, not only is a promising candidate for optoelectronic devices but also has potential for ultrathin field effect transistor (FET) with high mobility transport. In this work, various substrates such as PMMA, bare silicon oxide, passivated silicon oxide, and silicon nitride were used to fabricate multilayer InSe FET devices. Through back gating and Hall measurement in four-probe configuration, the device's field effect mobility and intrinsic Hall mobility were extracted at various temperatures to study the material's intrinsic transport behavior and the effect of dielectric substrate. The sample's field effect and Hall mobilities over the range of 20-300 K fall in the range of 0.1-2.0 × 10(3) cm(2)/(V s), which are comparable or better than the state of the art FETs made of widely studied 2D transition metal dichalcogenides.
Improved surface-roughness scattering and mobility models for multi-gate FETs with arbitrary cross-section and biasing scheme

NASA Astrophysics Data System (ADS)

Lizzit, D.; Badami, O.; Specogna, R.; Esseni, D.

2017-06-01

We present a new model for surface roughness (SR) scattering in n-type multi-gate FETs (MuGFETs) and gate-all-around nanowire FETs with fairly arbitrary cross-sections, its implementation in a complete device simulator, and the validation against experimental electron mobility data. The model describes the SR scattering matrix elements as non-linear transformations of interface fluctuations, which strongly influences the root mean square value of the roughness required to reproduce experimental mobility data. Mobility simulations are performed via the deterministic solution of the Boltzmann transport equation for a 1D-electron gas and including the most relevant scattering mechanisms for electronic transport, such as acoustic, polar, and non-polar optical phonon scattering, Coulomb scattering, and SR scattering. Simulation results show the importance of accounting for arbitrary cross-sections and biasing conditions when compared to experimental data. We also discuss how mobility is affected by the shape of the cross-section as well as by its area in gate-all-around and tri-gate MuGFETs.
A Theoretical Model of EGM Problem Gambling: More than a Cognitive Escape

ERIC Educational Resources Information Center

Thomas, Anna Christina; Sullivan, Gavin Brent; Allen, Felicity Catherine Louise

2009-01-01

Although electronic gaming machine (EGM) gambling is established as a particularly risky form of gambling (Dowling, Smith and Thomas, "Addiction" 100:33-45, 2005), models of problem gambling continue to be generalist so factors and processes specific to EGM gambling can be overlooked. This study conducted semi-structured interviews with 13 EGM…
Correlation of Electronic Health Records Use and Reduced Prevalence of Diabetes Co-Morbidities

ERIC Educational Resources Information Center

Eller, James D.

2013-01-01

The general problem is Native American tribes have high prevalence rates of diabetes. The specific problem is the failure of IHS sites to adopt EHR may cause health care providers to miss critical opportunities to improve screening and triage processes that result in quality improvement. The purpose of the quantitative correlational study was to…
Mobile internet and technology for optical teaching reform in higher education

NASA Astrophysics Data System (ADS)

Zhou, Muchun; Zhao, Qi; Chen, Yanru

2017-08-01

There are some problems in optical education such as insufficient flexibility, individuality and adaptability to students who need information and education at present. The development of mobile internet and technology provides support to solve these problems. Basic characteristics, advantages and developments of these techniques used in education are presented in this paper. Mobile internet is introduced to reform the classroom teaching of optical courses. Mobile network tool selection, teaching resources construction and reform in teaching methods are discussed. Academic record and sampling surveys are used to assess intention to adopt mobile internet and learning effect of academic major of students, the results show that high quality optical education can be offered by adopting mobile internet and technologies in traditional instruction.
Use and acceptance of electronic communication by patients with multiple sclerosis: a multicenter questionnaire study.

PubMed

Haase, Rocco; Schultheiss, Thorsten; Kempcke, Raimar; Thomas, Katja; Ziemssen, Tjalf

2012-10-15

The number of multiple sclerosis (MS) information websites, online communities, and Web-based health education programs has been increasing. However, MS patients' willingness to use new ways of communication, such as websites, mobile phone application, short message service, or email with their physician, remains unknown. We designed a questionnaire to evaluate the a priori use of electronic communication methods by MS patients and to assess their acceptance of such tools for communication with their health care providers. We received complete data from 586 MS patients aged between 17 and 73 years. Respondents were surveyed in outpatient clinics across Germany using a novel paper-and-pencil questionnaire. In addition to demographics, the survey items queried frequency of use of, familiarity with, and comfort with using computers, websites, email, and mobile phones. About 90% of all MS patients used a personal computer (534/586) and the Internet (527/586) at least once a week, 87.0% (510/586) communicated by email, and 85.6% (488/570) communicated by mobile phone. When asked about their comfort with using electronic communication methods for communication with health care providers, 20.5% (120/586) accepted communication by mobile Internet application or short message service via mobile phone, 41.0% (240/586) by websites, 54.3% (318/586) by email service, and 67.8% (397/586) by at least one type of electronic communication. The level of a priori use was the best predictor for the acceptance of electronic communication with health care providers. Patients who reported already searching online for health information (odds ratio 2.4, P < .001) and who had already communicated with a physician through a website (odds ratio 3.3, P = .03) reported higher acceptance for Web-based communication. Patients who already scheduled appointments with their mobile phones (odds ratio 2.1, P = .002) were more likely to accept the use of mobile phone applications or short message service for communicating with their physician. The majority of MS patients seen at specialist centers already use modern communication technology regularly. New forms of electronic communication appear to have high levels of acceptance for exchanging information about MS between patients and health care providers. Such methods should be integrated into eHealth services such as electronic health records and patient relationship management systems.
Electron mobility in mercury cadmium telluride

NASA Technical Reports Server (NTRS)

Patterson, James D.

1988-01-01

A previously developed program, which includes all electronic interactions thought to be important, does not correctly predict the value of electron mobility in mercury cadmium telluride particularly near room temperature. Part of the reason for this discrepancy is thought to be the way screening is handled. It seems likely that there are a number of contributors to errors in the calculation. The objective is to survey the calculation, locate reasons for differences between experiment and calculation, and suggest improvements.
Epitaxial Growth and Electronic Structure of Half Heuslers Co1-xNixTiSb (001), Ni1-xCoxTiSn, and PtLuSb

DTIC Science & Technology

2016-01-09

studied in detail using scanning tunneling microscopy and angle resolved photoemission. For the doping levels achieved in cobalt titanium antimony, the...angle resolved photoemission. For the doping levels achieved in cobalt titanium antimony, the electron mobility at room temperature was comparable...scanning tunneling microscopy and angle resolved photoemission. For the doping levels achieved in cobalt titanium antimony, the electron mobility at room
A study of electrically active traps in AlGaN/GaN high electron mobility transistor

NASA Astrophysics Data System (ADS)

Yang, Jie; Cui, Sharon; Ma, T. P.; Hung, Ting-Hsiang; Nath, Digbijoy; Krishnamoorthy, Sriram; Rajan, Siddharth

2013-10-01

We have studied electron conduction mechanisms and the associated roles of the electrically active traps in the AlGaN layer of an AlGaN/GaN high electron mobility transistor structure. By fitting the temperature dependent I-V (Current-Voltage) curves to the Frenkel-Poole theory, we have identified two discrete trap energy levels. Multiple traces of I-V measurements and constant-current injection experiment all confirm that the main role of the traps in the AlGaN layer is to enhance the current flowing through the AlGaN barrier by trap-assisted electron conduction without causing electron trapping.
Teaching smartphone and microcontroller systems using "Android Java"

NASA Astrophysics Data System (ADS)

Tigrek, Seyitriza

Mobile devices are becoming indispensable tools for many students and educators. Mobile technology is starting a new era in the computing methodologies in many engineering disciplines and laboratories. Microcontroller extension that communicates with mobile devices will take the data acquisition and control process into a new level in the sensing technology and communication. The purpose of this thesis is to develop a framework to incorporate the new mobile platform with robust embedded systems into the engineering curriculum. For this purpose a course material is developed "Introduction to Programming Java on a Mobile Platform" to teach novice programmers how to create applications, specifically on Android. Combining an introductory level programming class with the Android platform can appeal to non-programming individuals in multiple disciplines. The proposed course curriculum reduces the learning time, and allows senior engineering students to use the new framework for their specific needs in the labs such as mobile data acquisition and control projects. This work provides techniques for instructors with modest programming background to teach cutting edge technology, which is smartphone programming. Techniques developed in this work minimize unnecessary information carried into current teaching approaches with hands-on practice. It also helps the students with minimal background requirements overcome the barriers that have evolved around computer programming. The motivation of this thesis is to create a tailored programming introductory course to teach Java programming on Android by incorporating selected efficient methods from extant literature. The mechanism proposed in this thesis is to keep students motivated by an active approach based on student-centered learning with collaborative work. Teamwork through pair programming is adapted in this teaching process. Bloom's taxonomy, along with a knowledge survey, is used as a guide to classify the information and exercise problems. A prototype curriculum is a deliverable of this research that is suitable for novice programmers-such as engineering freshmen students. It also contains advanced material that allows senior students to use mobile phone and a microcontroller system to enhance engineering laboratories.
Wavefunction Properties and Electronic Band Structures of High-Mobility Semiconductor Nanosheet MoS2

NASA Astrophysics Data System (ADS)

Baik, Seung Su; Lee, Hee Sung; Im, Seongil; Choi, Hyoung Joon; Ccsaemp Team; Edl Team

2014-03-01

Molybdenum disulfide (MoS2) nanosheet is regarded as one of the most promising alternatives to the current semiconductors due to its significant band-gap and electron-mobility enhancement upon exfoliating. To elucidate such thickness-dependent properties, we have studied the electronic band structures of bulk and monolayer MoS2 by using the first-principles density-functional method as implemented in the SIESTA code. Based on the wavefunction analyses at the conduction band minimum (CBM) points, we have investigated possible origins of mobility difference between bulk and monolayer MoS2. We provide formation energies of substitutional impurities at the Mo and S sites, and discuss feasible electron sources which may induce a significant difference in the carrier lifetime. This work was supported by NRF of Korea (Grant Nos. 2009-0079462 and 2011-0018306), Nano-Material Technology Development Program (2012M3a7B4034985), and KISTI supercomputing center (Project No. KSC-2013-C3-008). Center for Computational Studies of Advanced Electronic Material Properties.

Physiotherapy to improve physical activity in community-dwelling older adults with mobility problems (Coach2Move): study protocol for a randomized controlled trial

PubMed Central

2013-01-01

Background Older adults can benefit from physical activity in numerous ways. Physical activity is considered to be one of the few ways to influence the level of frailty. Standardized exercise programs do not necessarily lead to more physical activity in daily life, however, and a more personalized approach seems appropriate. The main objective of this study is to investigate whether a focused, problem-oriented coaching intervention (‘Coach2Move’) delivered by a physiotherapist specializing in geriatrics is more effective for improving physical activity, mobility and health status in community-dwelling older adults than usual physiotherapy care. In addition, cost-effectiveness will be determined. Methods/Design The design of this study is a single-blind randomized controlled trial in thirteen physiotherapy practices. Randomization will take place at the individual patient level. The study population consists of older adults, ≥70 years of age, with decreased physical functioning and mobility and/or a physically inactive lifestyle. The intervention group will receive geriatric physiotherapy according to the Coach2Move strategy. The control group will receive the usual physiotherapy care. Measurements will be performed by research assistants not aware of group assignment. The results will be evaluated on the amount of physical activity (LASA Physical Activity Questionnaire), mobility (modified ‘get up and go’ test, walking speed and six-minute walking test), quality of life (SF-36), degree of frailty (Evaluative Frailty Index for Physical Activity), fatigue (NRS-fatigue), perceived effect (Global Perceived Effect and Patient Specific Complaints questionnaire) and health care costs. Discussion Most studies on the effect of exercise or physical activity consist of standardized programs. In this study, a personalized approach is evaluated within a group of frail older adults, many of whom suffer from multiple and complex diseases and problems. A complicating factor in evaluating a new approach is that it may not be automatically adopted by clinicians. Specific actions are undertaken to optimize implementation of the Coach2Move strategy during the trial. Whether or not these will be sufficient is a matter we will consider subsequently, using quality indicators and process analysis. Trial Registration The Netherlands National Trial Register: NTR3527. PMID:24345073
75 FR 40833 - Sunshine Act Meeting; Open Commission Meeting; Thursday, July 15, 2010

Federal Register 2010, 2011, 2012, 2013, 2014

2010-07-14

... OFFICE OF TITLE: Fixed and ENGINEERING AND Mobile services TECHNOLOGY, in the Mobile WIRELESS TELE... investment in the 2 GHz, Big LEO, and L-bands of the Mobile Satellite Service. 3 WIRELINE TITLE: Electronic...
Nitrogen-related effects on low-temperature electronic properties of two-dimensional electron gas in very dilute nitride GaNxAs1-x/AlGaAs (x = 0 and 0.08%) modulation-doped heterostructures

NASA Astrophysics Data System (ADS)

Mootabian, Mahnaz; Eshghi, Hosein

2013-07-01

The low-temperature (4 K) two-dimensional (2D) electron gas mobility data versus carrier concentration in the modulation-doped dilute nitride GaAs1-xNx/Al0.3Ga0.7As (x = 0 and 0.08%) heterostructures are analyzed. Theoretical analysis is based on Fermi-Dirac statistics for the occupation of the quantum confined electronic states in the triangular quantum wells and the width of the quantum well versus 2D concentration. In addition, the mobility analysis is based on Matthiessen's rule for various scattering mechanisms. We found that the N-related neutral cluster alloy scattering together with crystal dislocations created at the interface strongly affects the electrons' mobility in the N-contained channel sample. We also found that as the electron concentration in the well increases from ˜1 × 1011 to 3.5 × 1011 cm-2 the carriers mainly occupy the first subband, tending to remain closer and closer to the hetero-interface.
Gastrointestinal symptoms resembling ulcerative proctitis caused by larvae of the drone fly Eristalis tenax.

PubMed

Desoubeaux, Guillaume; Gaillard, Julien; Borée-Moreau, Diane; Bailly, Éric; Andres, Christian R; Chandenier, Jacques

2014-04-01

We report a case of facultative intestinal myiasis due to larvae of the drone fly Eristalis tenax, also named the rat-tailed maggots. The development of larvae in the lower bowel was responsible for non-specific gastrointestinal symptoms that resembled ulcerative proctitis. The diagnosis was established upon the observation of four spontaneously excreted mobile larvae. The definite identification of the E. tenax species was made possible by scanning electron microscopy. The clinical outcome was satisfactory.
Gastrointestinal symptoms resembling ulcerative proctitis caused by larvae of the drone fly Eristalis tenax

PubMed Central

Desoubeaux, Guillaume; Gaillard, Julien; Borée-Moreau, Diane; Bailly, Éric; Andres, Christian R; Chandenier, Jacques

2014-01-01

We report a case of facultative intestinal myiasis due to larvae of the drone fly Eristalis tenax, also named the rat-tailed maggots. The development of larvae in the lower bowel was responsible for non-specific gastrointestinal symptoms that resembled ulcerative proctitis. The diagnosis was established upon the observation of four spontaneously excreted mobile larvae. The definite identification of the E. tenax species was made possible by scanning electron microscopy. The clinical outcome was satisfactory. PMID:24766340
The use of mobile learning application to the fundament of digital electronics course

NASA Astrophysics Data System (ADS)

Rakhmawati, L.; Firdha, A.

2018-01-01

A new trend in e-learning is known as Mobile Learning. Learning through mobile phones have become part of the educative process. Thus, the purposes of this study are to develop a mobile application for the Fundament of Digital Electronics course that consists of number systems operation, logic gates, and Boolean Algebra, and to assess the readiness, perceptions, and effectiveness of students in the use of mobile devices for learning in the classroom. This research uses Research and Development (R&D) method. The design used in this research, by doing treatment in one class and observing by using Android-based mobile application instructional media. The result obtained from this research shows that the test has 80 % validity aspect, 82 % of the user from senior high school students gives a positive response in using the application of mobile learning, and based on the result of post-test, 90, 90% students passed the exam. At last, it can be concluded that the use of the mobile learning application makes the learning process more effective when it is used in the teaching-learning process.
The Association Between Electronic Media and Emotional and Behavioral Problems in Late Childhood.

PubMed

Mundy, Lisa K; Canterford, Louise; Olds, Timothy; Allen, Nicholas B; Patton, George C

2017-08-01

There is growing concern that rising rates of electronic media use might be harmful. However, the extent to which different types of electronic media use might be associated with emotional and behavioral problems is unclear. In this study we examined associations between emotional and behavioral problems and electronic media use during late childhood, in a large community sample. Participants were 876 8- to 9-year-old children taking part in the Childhood to Adolescence Transition Study in Australia. Parents reported on their child's emotional and behavioral problems using the Strengths and Difficulties Questionnaire and on their child's duration of electronic media use (in hours: television, video games, general computer use). Logistic regression analyses were conducted with adjustments for age, socioeconomic status, and body mass index z score, separately for male and female participants. Boys who played more video games had significantly greater odds of scoring borderline/abnormal on conduct (odds ratio [OR], 1.07; 95% confidence interval [CI], 1.02-1.12) and emotional problems (OR, 1.07; 95% CI, 1.04-1.11) for each additional hour of weekly use. This equates to 2.58-fold greater odds for a boy who plays on average 2 hours per day per week. Television viewing was associated with greater odds of hyperactivity/inattention in boys (OR, 1.04; 95% CI, 1.00-1.07). There were no significant relationships for girls. Because of the increasing rates of electronic media use in children, these results might have important implications for child mental health. Future interventions might be more effective if they are targeted at specific types of electronic media use. Copyright © 2016 Academic Pediatric Association. Published by Elsevier Inc. All rights reserved.
Prediction of a mobile two-dimensional electron gas at the LaSc O3 /BaSn O3 (001) interface

NASA Astrophysics Data System (ADS)

Paudel, Tula R.; Tsymbal, Evgeny Y.

2017-12-01

Two-dimensional electron gases (2DEG) at oxide interfaces, such as LaAl O3 /SrTi O3 (001), have aroused significant interest due to their high carrier density (˜1014c m-2 ) and strong lateral confinement (˜1 nm). However, these 2DEGs are normally hosted by the weakly dispersive and degenerate d bands (e.g., Ti -3 d bands), which are strongly coupled to the lattice, causing mobility of such 2DEGs to be relatively low at room temperature (˜1 c m2/Vs ). Here, we propose using oxide host materials with the conduction bands formed from s electrons to increase carrier mobility and soften its temperature dependence. Using first-principles density functional theory calculations, we investigate LaSc O3 /BaSn O3 (001) heterostructure and as a model system, where the conduction band hosts the s -like carriers. We find that the polar discontinuity at this interface leads to electronic reconstruction resulting in the formation of the 2DEG at this interface. The conduction electrons reside in the highly dispersive Sn -5 s bands, which have a large band width and a low effective mass. The predicted 2DEG is expected to be highly mobile even at room temperature due to the reduced electron-phonon scattering via the inter-band scattering channel. A qualitatively similar behavior is predicted for a doped BaSn O3 , where a monolayer of BaO is replaced with LaO. We anticipate that the quantum phenomena associated with these 2DEGs to be more pronounced owing to the high mobility of the carriers.
Performance Analysis of GaN Capping Layer Thickness on GaN/AlGaN/GaN High Electron Mobility Transistors.

PubMed

Sharma, N; Periasamy, C; Chaturvedi, N

2018-07-01

In this paper, we present an investigation of the impact of GaN capping layer and AlGaN layer thickness on the two-dimensional (2D)-electron mobility and the carrier concentration which was formed close to the AlGaN/GaN buffer layer for Al0.25Ga0.75N/GaN and GaN/Al0.25Ga0.75N/GaN heterostructures deposited on sapphire substrates. The results of our analysis clearly indicate that expanding the GaN capping layer thickness from 1 nm to 100 nm prompts an increment in the electron concentration at hetero interface. As consequence of which drain current was additionally increments with GaN cap layer thicknesses, and eventually saturates at approximately 1.85 A/mm for capping layer thickness greater than 40 nm. Interestingly, for the same structure, the 2D-electron mobility, decrease monotonically with GaN capping layer thickness, and saturate at approximately 830 cm2/Vs for capping layer thickness greater than 50 nm. A device with a GaN cap layer didn't exhibit gate leakage current. Furthermore, it was observed that the carrier concentration was first decrease 1.03 × 1019/cm3 to 6.65 × 1018/cm3 with AlGaN Layer thickness from 5 to 10 nm and after that it increases with the AlGaN layer thickness from 10 to 30 nm. The same trend was followed for electric field distributions. Electron mobility decreases monotonically with AlGaN layer thickness. Highest electron mobility 1354 cm2/Vs were recorded for the AlGaN layer thickness of 5 nm. Results obtained are in good agreement with published experimental data.
Medical isotope identification with large mobile detection systems

NASA Astrophysics Data System (ADS)

Mukhopadhyay, Sanjoy; Maurer, Richard

2012-10-01

The Remote Sensing laboratory (RSL) of National Security Technologies Inc. has built an array of large (5.08 - cm x 10.16 - cm x 40.6 - cm) thallium doped sodium iodide (NaI: Tl) scintillators to locate and screen gamma-ray emitting radioisotopes that are of interests to radiological emergency responders [1]. These vehicle mounted detectors provide the operators with rapid, simple, specific information for radiological threat assessment. Applications include large area inspection, customs inspection, border protection, emergency response, and monitoring of radiological facilities. These RSL mobile units are currently being upgraded to meet the Defense Threat Reduction Agency mission requirements for a next-generation system capable of detecting and identifying nuclear threat materials. One of the challenging problems faced by these gamma-ray detectors is the unambiguous identification of medical isotopes like 131I (364.49 keV [81.7%], 636.99 keV [7.17%]), 99Tcm (140.51 keV [89.1%]) and 67Ga (184.6 keV [19.7%], 300.2 [16.0%], 393.5 [4.5%] that are used in radionuclide therapy and often have overlapping gamma-ray energy regions of interest (ROI). The problem is made worse by short (about 5 seconds) acquisition time of the spectral data necessary for dynamic mobile detectors. This article describes attempts to identify medical isotopes from data collected from this mobile detection system in a short period of time (not exceeding 5 secs) and a large standoff distance (typically 10 meters) The mobile units offer identification capabilities that are based on hardware auto stabilization of the amplifier gain. The 1461 keV gamma-energy line from 40K is tracked. It uses gamma-ray energy windowing along with embedded mobile Gamma Detector Response and Analysis Software (GADRAS) [2] simultaneously to deconvolve any overlapping gamma-energy ROIs. These high sensitivity detectors are capable of resolving complex masking scenarios and exceed all ANSI N42.34 (2006) requirements for the identification of bare, shielded and multiple isotopes.
Intrinsic mobility limit for anisotropic electron transport in Alq3.

PubMed

Drew, A J; Pratt, F L; Hoppler, J; Schulz, L; Malik-Kumar, V; Morley, N A; Desai, P; Shakya, P; Kreouzis, T; Gillin, W P; Kim, K W; Dubroka, A; Scheuermann, R

2008-03-21

Muon spin relaxation has been used to probe the charge carrier motion in the molecular conductor Alq3 (tris[8-hydroxy-quinoline] aluminum). At 290 K, the magnetic field dependence of the muon spin relaxation corresponds to that expected for highly anisotropic intermolecular electron hopping. Intermolecular mobility in the fast hopping direction has been found to be 0.23+/-0.03 cm2 V-1 s(-1) in the absence of an electric- field gradient, increasing to 0.32+/-0.06 cm2 V-1 s(-1) in an electric field gradient of 1 MV m(-1). These intrinsic mobility values provide an estimate of the upper limit for mobility achievable in bulk material.
A numerical study of mobility in thin films of fullerene derivatives.

PubMed

Mackenzie, Roderick C I; Frost, Jarvist M; Nelson, Jenny

2010-02-14

The effect of functional group size on the electron mobility in films of fullerene derivatives is investigated numerically. A series of four C(60) derivatives are formed by attaching saturated hydrocarbon chains to the C(60) cage via a methano bridge. For each of the derivatives investigated, molecular dynamics is used to generate a realistic material morphology. Quantum chemical methods are then used to calculate intermolecular charge transfer rates. Finally, Monte Carlo methods are used to simulate time-of-flight experiments and thus calculate the electron mobility. It is found that as the length of the aliphatic side chain increases, the configurational disorder increases and thus the mobility decreases.
Problems With Deployment of Multi-Domained, Multi-Homed Mobile Networks

NASA Technical Reports Server (NTRS)

Ivancic, William D.

2008-01-01

This document describes numerous problems associated with deployment of multi-homed mobile platforms consisting of multiple networks and traversing large geographical areas. The purpose of this document is to provide insight to real-world deployment issues and provide information to groups that are addressing many issues related to multi-homing, policy-base routing, route optimization and mobile security - particularly those groups within the Internet Engineering Task Force.
Thermal Analysis of AlGaN/GaN High-Electron-Mobility Transistor and Its RF Power Efficiency Optimization with Source-Bridged Field-Plate Structure.

PubMed

Kwak, Hyeon-Tak; Chang, Seung-Bo; Jung, Hyun-Gu; Kim, Hyun-Seok

2018-09-01

In this study, we consider the relationship between the temperature in a two-dimensional electron gas (2-DEG) channel layer and the RF characteristics of an AlGaN/GaN high-electron-mobility transistor by changing the geometrical structure of the field-plate. The final goal is to achieve a high power efficiency by decreasing the channel layer temperature. First, simulations were performed to compare and contrast the experimental data of a conventional T-gate head structure. Then, a source-bridged field-plate (SBFP) structure was used to obtain the lower junction temperature in the 2-DEG channel layer. The peak electric field intensity was reduced, and a decrease in channel temperature resulted in an increase in electron mobility. Furthermore, the gate-to-source capacitance was increased by the SBFP structure. However, under the large current flow condition, the SBFP structure had a lower maximum temperature than the basic T-gate head structure, which improved the device electron mobility. Eventually, an optimum position of the SBFP was used, which led to higher frequency responses and improved the breakdown voltages. Hence, the optimized SBFP structure can be a promising candidate for high-power RF devices.
Development of Cryogenic Enhancement-Mode Pseudomorphic High-Electron-Mobility Transistor Amplifier

NASA Astrophysics Data System (ADS)

Hirata, T.; Okazaki, T.; Obara, K.; Yano, H.; Ishikawa, O.

2017-06-01

This paper reports the technical details of the development of a low-temperature amplifier for nuclear magnetic resonance measurements of superfluid {}^3He in very confined geometries. The amplifier consists of commercially available enhancement-mode pseudomorphic high-electron-mobility transistor devices and temperature-insensitive passive components with an operating frequency range of 0.2-6 MHz.
The Use of Monolingual Mobile Dictionaries in the Context of Reading by Intermediate Cantonese EFL Learners in Hong Kong

ERIC Educational Resources Information Center

Zou, Di; Xie, Haoran; Wang, Fu Lee

2015-01-01

Previous studies on dictionary consultation investigated mainly online dictionaries or simple pocket electronic dictionaries as they were commonly used among learners back then, yet the more updated mobile dictionaries were superficially investigated though they have already replaced the pocket electronic dictionaries. These studies are also…
Microsystems, Space Qualified Electronics and Mobile Sensor Platforms for Harsh Environment Applications and Planetary Exploration

NASA Technical Reports Server (NTRS)

Hunter, Gary W.; Okojie, Robert S.; Krasowski, Michael J.; Beheim, Glenn M.; Fralick, Gustave C.; Wrbanek, John D.; Greenberg, Paul S.; Xu, Jennifer

2007-01-01

NASA Glenn Research Center is presently developing and applying a range of sensor and electronic technologies that can enable future planetary missions. These include space qualified instruments and electronics, high temperature sensors for Venus missions, mobile sensor platforms, and Microsystems for detection of a range of chemical species and particulates. A discussion of each technology area and its level of maturity is given. It is concluded that there is a strong need for low power devices which can be mobile and provide substantial characterization of the planetary environment where and when needed. While a given mission will require tailoring of the technology for the application, basic tools which can enable new planetary missions are being developed.
Electronic structures of superionic conductor Li3N

NASA Astrophysics Data System (ADS)

Aoki, Masaru; Ode, Yoshiyuki; Tsumuraya, Kazuo

2011-03-01

Lithium nitride is a superionic conductor with high Li conductivity. The compound has been studied extensively because of its potential utility as electrolyte in solid-state batteries. Though the mobility of the cations within the crystalline solid is high comparable to that of molten salts, the mechanism of the high mobility of the cations remains unsolved. To clarify the origin of the mobility we investigate the electronic states of the Li cations in the Li 3 N crystal with the first principles electronic structure analysis, focusing a correlation between the cations and the ionicities of the constituent atoms. We have found the existence of the covalent bonding between the Li atoms in the Li 3 N crystal in spite of the ionized states of the constituent atoms.
Molecular gated-AlGaN/GaN high electron mobility transistor for pH detection.

PubMed

Ding, Xiangzhen; Yang, Shuai; Miao, Bin; Gu, Le; Gu, Zhiqi; Zhang, Jian; Wu, Baojun; Wang, Hong; Wu, Dongmin; Li, Jiadong

2018-04-18

A molecular gated-AlGaN/GaN high electron mobility transistor has been developed for pH detection. The sensing surface of the sensor was modified with 3-aminopropyltriethoxysilane to provide amphoteric amine groups, which would play the role of receptors for pH detection. On modification with 3-aminopropyltriethoxysilane, the transistor exhibits good chemical stability in hydrochloric acid solution and is sensitive for pH detection. Thus, our molecular gated-AlGaN/GaN high electron mobility transistor acheived good electrical performances such as chemical stability (remained stable in hydrochloric acid solution), good sensitivity (37.17 μA/pH) and low hysteresis. The results indicate a promising future for high-quality sensors for pH detection.
Growth and Transport Studies of LaTiO3 / KTaO3 Heterostructures

NASA Astrophysics Data System (ADS)

Zou, K.; Walker, F. J.; Ahn, C. H.

2014-03-01

Perovskite oxide heterostructures provide a rich platform for exploring emergent electronic properties, such as 2D electron gases (2DEGs) at interfaces. In this talk, we present results on the growth of LaTiO3 / KTaO3 heterostructures by molecular beam epitaxy and subsequent measurements of transport properties. Although both oxide materials are insulating in the bulk, metallic conduction is observed from T = 2 - 300 K. We achieve a room temperature carrier mobility of ~ 25 cm2 /Vs at a carrier density of ~ 1014 /cm2. By comparison, 2DEGs in LaTiO3 / SrTiO3 and LaAlO3 / SrTiO3 have lower carrier mobility, but the same carrier density. We attribute some of the increase in mobility to the smaller band effective mass of the Ta 4d electrons compared to the Ti 3d electrons.

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