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Sample records for doping control purposes

  1. Mass spectrometric characterization of urinary metabolites of the selective androgen receptor modulator andarine (S-4) for routine doping control purposes.

    PubMed

    Thevis, Mario; Thomas, Andreas; Fusshöller, Gregor; Beuck, Simon; Geyer, Hans; Schänzer, Wilhelm

    2010-08-15

    Selective androgen receptor modulators (SARMs) are potent anabolic agents with tissue-selective properties. Due to their potential misuse in elite sport, the World Anti-Doping Agency (WADA) has prohibited SARMs since 2008, and although no representative drug candidate has yet received full clinical approval, recent findings of SARMs illegally sold via the internet have further supported the need to efficiently test for these compounds in doping controls. In the present communication, the mass spectrometric characterization of urinary metabolites of the SARM Andarine (also referred to as S-4) compared with earlier in vitro and animal studies is reported. Liquid chromatography interfaced to high-resolution/high-accuracy (tandem) mass spectrometry was used to identify phase I and II metabolites, confirming the predicted target analytes for sports drug testing purposes including the glucuronic acid conjugates of the active drug, its monohydroxylated and/or deacetylated product, the hydrolysis product resulting from the removal of the compound's B-ring, as well as the sulfate of the monohydroxylated and the deacetylated phase I metabolite. The obtained data will support future efforts to effectively screen for and confirm the misuse of the non-approved drug candidate Andarine. PMID:20623476

  2. Identification of selected in vitro generated phase-I metabolites of the steroidal selective androgen receptor modulator MK-0773 for doping control purposes.

    PubMed

    Lagojda, Andreas; Kuehne, Dirk; Krug, Oliver; Thomas, Andreas; Wigger, Tina; Karst, Uwe; Schänzer, Wilhelm; Thevis, Mario

    2016-01-01

    Research into developing anabolic agents for various therapeutic purposes has been pursued for decades. As the clinical utility of anabolic-androgenic steroids has been found to be limited because of their lack of tissue selectivity and associated off-target effects, alternative drug entities have been designed and are commonly referred to as selective androgen receptor modulators (SARMs). While most of these SARMs are of nonsteroidal structure, the drug candidate MK-0773 comprises a 4-aza-steroidal nucleus. Besides the intended therapeutic use, SARMs have been found to be illicitly distributed and misused as doping agents in sport, necessitating frequently updated doping control analytical assays. As steroidal compounds reportedly undergo considerable metabolic transformations, the phase-I metabolism of MK-0773 was simulated using human liver microsomal (HLM) preparations and electrochemical conversion. Subsequently, major metabolic products were identified and characterized employing liquid chromatography-high-resolution/high- accuracy tandem mass spectrometry with electrospray (ESI) and atmospheric pressure chemical ionization (APCI) as well as nuclear magnetic resonance (NMR) spectroscopy. MK-0773 produced numerous phase-I metabolites under the chosen in vitro incubation reactions, mostly resulting from mono- and bisoxygenation of the steroid. HLM yielded at least 10 monooxygenated species, while electrochemistry-based experiments resulted predominantly in three monohydroxylated metabolites. Elemental composition data and product ion mass spectra were generated for these analytes, ESI/APCI measurements corroborated the formation of at least two N-oxygenated metabolites, and NMR data obtained from electrochemistry-derived products supported structures suggested for three monohydroxylated compounds. Hereby, the hydroxylation of the A-ring located N- bound methyl group was found to be of particular intensity. In the absence of controlled elimination studies, the

  3. Identification of selected in vitro generated phase-I metabolites of the steroidal selective androgen receptor modulator MK-0773 for doping control purposes.

    PubMed

    Lagojda, Andreas; Kuehne, Dirk; Krug, Oliver; Thomas, Andreas; Wigger, Tina; Karst, Uwe; Schänzer, Wilhelm; Thevis, Mario

    2016-01-01

    Research into developing anabolic agents for various therapeutic purposes has been pursued for decades. As the clinical utility of anabolic-androgenic steroids has been found to be limited because of their lack of tissue selectivity and associated off-target effects, alternative drug entities have been designed and are commonly referred to as selective androgen receptor modulators (SARMs). While most of these SARMs are of nonsteroidal structure, the drug candidate MK-0773 comprises a 4-aza-steroidal nucleus. Besides the intended therapeutic use, SARMs have been found to be illicitly distributed and misused as doping agents in sport, necessitating frequently updated doping control analytical assays. As steroidal compounds reportedly undergo considerable metabolic transformations, the phase-I metabolism of MK-0773 was simulated using human liver microsomal (HLM) preparations and electrochemical conversion. Subsequently, major metabolic products were identified and characterized employing liquid chromatography-high-resolution/high- accuracy tandem mass spectrometry with electrospray (ESI) and atmospheric pressure chemical ionization (APCI) as well as nuclear magnetic resonance (NMR) spectroscopy. MK-0773 produced numerous phase-I metabolites under the chosen in vitro incubation reactions, mostly resulting from mono- and bisoxygenation of the steroid. HLM yielded at least 10 monooxygenated species, while electrochemistry-based experiments resulted predominantly in three monohydroxylated metabolites. Elemental composition data and product ion mass spectra were generated for these analytes, ESI/APCI measurements corroborated the formation of at least two N-oxygenated metabolites, and NMR data obtained from electrochemistry-derived products supported structures suggested for three monohydroxylated compounds. Hereby, the hydroxylation of the A-ring located N- bound methyl group was found to be of particular intensity. In the absence of controlled elimination studies, the

  4. Mass spectrometric studies on the in vivo metabolism and excretion of SIRT1 activating drugs in rat urine, dried blood spots, and plasma samples for doping control purposes.

    PubMed

    Höppner, Sebastian; Delahaut, Philippe; Schänzer, Wilhelm; Thevis, Mario

    2014-01-01

    The NAD(+) depending enzyme SIRT1 regulates the mitochondrial biogenesis, fat and glucose metabolism through catalyzing the deacetylation of several metabolism-related protein-substrates. Recently, synthetic activators of SIRT1 referred to as STACs (Sirtuin activating compounds, e.g. SRT2104) were identified and tested in clinical studies for the treatment of aging-related diseases such as type 2 diabetes, Alzheimer's and obesity. Although the mechanism of SIRT1 activation by small molecules has caused considerable controversy, STACs demonstrated a significant performance enhancement in mice experiments including an improvement of endurance, muscle strength, and locomotor behavior. Due to their potential to increase exercise tolerance in healthy individuals, SIRT1 activators are currently being monitored by anti-doping authorities. In the present study, the in vivo metabolic clearance of three SIRT1 activators was investigated in rats by the collection of urine, DBS (dried blood spots) and plasma samples following a single oral administration. The resulting metabolic products were studied by positive electrospray ionization - (tandem) mass spectrometry and confirmed by the comparison with in vitro generated metabolites using human and rat liver microsomal preparations. Subsequently, a screening procedure for five SIRT1 activators and the metabolite M1-SRT1720 in DBS specimens was developed. Liquid-liquid-extraction and liquid chromatography/tandem mass spectrometry was employed based on diagnostic ion transitions recorded in multiple reaction monitoring mode and two deuterated internal standards namely d8-SRT1720 and d8-M1-SRT1720 were utilized. The doping control assay was characterized with regard to specificity, limit of detection (10-50ng/ml), recovery (65-83%) and imprecision (7-20%) and ion suppression/enhancement effects (<10%), demonstrating its fitness-for-purpose for sports drug testing applications.

  5. Characterization of equine urinary metabolites of selective androgen receptor modulators (SARMs) S1, S4 and S22 for doping control purposes.

    PubMed

    Hansson, Annelie; Knych, Heather; Stanley, Scott; Thevis, Mario; Bondesson, Ulf; Hedeland, Mikael

    2015-08-01

    Selective androgen receptor modulators, SARMs, constitute a class of compounds with anabolic properties but with few androgenic side-effects. This makes them possible substances of abuse and the World Anti-Doping Agency (WADA) has banned the entire class of substances. There have been several cases of illicit use of aryl propionamide SARMs in human sports and in 2013, 13 cases were reported. These substances have been found to be extensively metabolized in humans, making detection of metabolites necessary for doping control. SARMs are also of great interest to equine doping control, but the in vivo metabolite pattern and thus possible analytical targets have not been previously studied in this species. In this study, the urinary metabolites of the SARMs S1, S4, and S22 in horses were studied after intravenous injection, using ultra high performance liquid chromatography coupled to quadrupole time-of-flight mass spectrometry (UHPLC-QToF-MS). Eight different metabolites were found for SARM S1, nine for SARM S4, and seven for SARM S22. The equine urinary metabolite profiles differed significantly from those of humans. The parent compounds were only detected for SARMs S4 and S22 and only at the first sampling time point at 3 h post administration, making them unsuitable as target compounds. For all three SARMs tested, the metabolite yielding the highest response had undergone amide hydrolysis, hydroxylation and sulfonation. The resulting phase II metabolites (4-nitro-3-trifluoro-methyl-phenylamine sulfate for SARMs S1 and S4 and 4-cyano-3-trifluoro-methyl-phenylamine sulfate for SARM S22) are proposed as analytical targets for use in equine doping control.

  6. Biomarker monitoring in sports doping control.

    PubMed

    Pottgiesser, Torben; Schumacher, Yorck Olaf

    2012-06-01

    Biomarker monitoring can be considered a new era in the effort against doping. Opposed to the old concept in doping control of direct detection of a prohibited substance in a biological sample such as urine or blood, the new paradigm allows a personalized longitudinal monitoring of biomarkers that indicate non-physiological responses independently of the used doping technique or substance, and may cause sanctioning of illicit practices. This review presents the development of biomarker monitoring in sports doping control and focuses on the implementation of the Athlete Biological Passport as the current concept of the World Anti Doping Agency for the detection of blood doping (hematological module). The scope of the article extends to the description of novel biomarkers and future concepts of application.

  7. Human genetic variation: new challenges and opportunities for doping control.

    PubMed

    Schneider, Angela J; Fedoruk, Matthew N; Rupert, Jim L

    2012-01-01

    Sport celebrates differences in competitors that lead to the often razor-thin margins between victory and defeat. The source of this variation is the interaction between the environment in which the athletes develop and compete and their genetic make-up. However, a darker side of sports may also be genetically influenced: some anti-doping tests are affected by the athlete's genotype. Genetic variation is an issue that anti-doping authorities must address as more is learned about the interaction between genotype and the responses to prohibited practices. To differentiate between naturally occurring deviations in indirect blood and urine markers from those potentially caused by doping, the "biological-passport" program uses intra-individual variability rather than population values to establish an athlete's expected physiological range. The next step in "personalized" doping control may be the inclusion of genetic data, both for the purposes of documenting an athlete's responses to doping agents and doping-control assays as well facilitating athlete and sample identification. Such applications could benefit "clean" athletes but will come at the expense of risks to privacy. This article reviews the instances where genetics has intersected with doping control, and briefly discusses the potential role, and ethical implications, of genotyping in the struggle to eliminate illicit ergogenic practices. PMID:22681541

  8. Human genetic variation: new challenges and opportunities for doping control.

    PubMed

    Schneider, Angela J; Fedoruk, Matthew N; Rupert, Jim L

    2012-01-01

    Sport celebrates differences in competitors that lead to the often razor-thin margins between victory and defeat. The source of this variation is the interaction between the environment in which the athletes develop and compete and their genetic make-up. However, a darker side of sports may also be genetically influenced: some anti-doping tests are affected by the athlete's genotype. Genetic variation is an issue that anti-doping authorities must address as more is learned about the interaction between genotype and the responses to prohibited practices. To differentiate between naturally occurring deviations in indirect blood and urine markers from those potentially caused by doping, the "biological-passport" program uses intra-individual variability rather than population values to establish an athlete's expected physiological range. The next step in "personalized" doping control may be the inclusion of genetic data, both for the purposes of documenting an athlete's responses to doping agents and doping-control assays as well facilitating athlete and sample identification. Such applications could benefit "clean" athletes but will come at the expense of risks to privacy. This article reviews the instances where genetics has intersected with doping control, and briefly discusses the potential role, and ethical implications, of genotyping in the struggle to eliminate illicit ergogenic practices.

  9. 15 CFR 730.6 - Control purposes.

    Code of Federal Regulations, 2014 CFR

    2014-01-01

    ... 15 Commerce and Foreign Trade 2 2014-01-01 2014-01-01 false Control purposes. 730.6 Section 730.6... Control purposes. The export control provisions of the EAR are intended to serve the national security..., which in many cases are reflected in international obligations or arrangements. Some controls...

  10. 15 CFR 730.6 - Control purposes.

    Code of Federal Regulations, 2010 CFR

    2010-01-01

    ... 15 Commerce and Foreign Trade 2 2010-01-01 2010-01-01 false Control purposes. 730.6 Section 730.6... Control purposes. The export control provisions of the EAR are intended to serve the national security... carry out its international obligations. Some controls are designed to restrict access to dual use...

  11. Doping control from a global and national perspective.

    PubMed

    Fraser, Albert D

    2004-04-01

    The practice of enhancing athletic performance through foreign substances was known from the earliest Olympic games. In 1967, the International Olympic Committee (IOC) established a Medical Commission responsible for developing a list of prohibited substances and methods. Drug tests were first introduced at the Olympic winter games in Grenoble and at the summer games in Mexico City in 1968. In February 1999, the IOC convened the World Conference on Doping in Sport in Lausanne, Switzerland. The Lausanne Declaration on Doping in Sport recommended creation of an International Anti-Doping Agency. The World Anti-Doping Agency (WADA) was formed in Lausanne, Switzerland on the basis of equal representation from the Olympic movement and public authorities. One of the mandates of WADA was to harmonize the Olympic antidoping code and develop a single code applicable and acceptable for all stakeholders. The world antidoping code developed by WADA included creation of several international standards (IS). The purpose of each IS was harmonization among antidoping organizations. The ISs were developed for laboratories, testing, the prohibited list, and for therapeutic use exemptions (TUE). The objective of this manuscript is to present a brief history of doping in sport and describe creation of WADA in 1999. The components of the World Anti-Doping code (in particular, the Therapeutic Use Exclusion program or TUE) is described. The WADA code defines a TUE as "permission to use, for therapeutic purposes, a drug or drugs which are otherwise prohibited in sporting competition." Experiences of the Canadian Centre for Ethics in Sport Doping Control Review Board are presented because this national TUE committee has been operational for over 12 years. The challenge of developing a rigorous global antidoping program requires acceptance of doping as a problem by sport organizations, athletes, and public authorities. Individual stakeholders must be prepared to preserve the values of sport

  12. Controlled doping of graphene using ultraviolet irradiation

    SciTech Connect

    Luo Zhengtang; Pinto, Nicholas J.; Davila, Yarely; Charlie Johnson, A. T.

    2012-06-18

    The electronic properties of graphene are tunable via doping, making it attractive in low dimensional organic electronics. Common methods of doping graphene, however, adversely affect charge mobility and degrade device performance. We demonstrate a facile shadow mask technique of defining electrodes on graphene grown by chemical vapor deposition (CVD) thereby eliminating the use of detrimental chemicals needed in the corresponding lithographic process. Further, we report on the controlled, effective, and reversible doping of graphene via ultraviolet (UV) irradiation with minimal impact on charge mobility. The change in charge concentration saturates at {approx}2 Multiplication-Sign 10{sup 12} cm{sup -2} and the quantum yield is {approx}10{sup -5} e/photon upon initial UV exposure. This simple and controlled strategy opens the possibility of doping wafer-size CVD graphene for diverse applications.

  13. Liquid chromatography-high resolution/ high accuracy (tandem) mass spectrometry-based identification of in vivo generated metabolites of the selective androgen receptor modulator ACP-105 for doping control purposes.

    PubMed

    Thevis, Mario; Thomas, Andreas; Piper, Thomas; Krug, Oliver; Delahaut, Philippe; Schänzer, Wilhelm

    2014-01-01

    Selective androgen receptor modulators (SARMs) represent an emerging class of therapeutics which have been prohibited in sport as anabolic agents according to the regulations of the World Anti-Doping Agency (WADA) since 2008. Within the past three years, numerous adverse analytical findings with SARMs in routine doping control samples have been reported despite missing clinical approval of these substances. Hence, preventive doping research concerning the metabolism and elimination of new therapeutic entities of the class of SARMs are vital for efficient and timely sports drug testing programs as banned compounds are most efficiently screened when viable targets (for example, characteristic metabolites) are identified. In the present study, the metabolism of ACP-105, a novel SARM drug candidate, was studied in vivo in rats. Following oral administration, urine samples were collected over a period of seven days and analyzed for metabolic products by Liquid chromatography-high resolution/high accuracy (tandem) mass spectrometry. Samples were subjected to enzymatic hydrolysis prior to liquid-liquid extraction and a total of seven major phase-I metabolites were detected, three of which were attributed to monohydroxylated and four to bishydroxylated ACP-105. The hydroxylation sites were assigned by means of diagnostic product ions and respective dissociation pathways of the analytes following positive or negative ionization and collisional activation as well as selective chemical derivatization. The identified metabolites were used as target compounds to investigate their traceability in a rat elimination urine samples study and monohydroxylated and bishydroxylated species were detectable for up to four and six days post-administration, respectively.

  14. Purpose Plus: Supporting Youth Purpose, Control, and Academic Achievement

    ERIC Educational Resources Information Center

    Pizzolato, Jane Elizabeth; Brown, Elizabeth Levine; Kanny, Mary Allison

    2011-01-01

    Research in the past decade suggests that a persistent achievement gap between students from low-income minority backgrounds and higher-income white backgrounds may be rooted in theories of student motivation and youth purpose. Yet limited research exists regarding the role of purpose on positive youth development as it pertains to academic…

  15. Controllable synthesis of doped graphene and its applications.

    PubMed

    Xue, Yunzhou; Wu, Bin; Bao, Qiaoliang; Liu, Yunqi

    2014-08-13

    Graphene is a wonder material with the ultimate smallest thickness that is readily accessible to various approaches for engineering its excellent properties. Graphene doping is an efficient way to tailor its electric properties and expand its applications. This topic covers wide research fields and has been developing rapidly. This article presents a broad and comprehensive overview of the developments in the preparation and applications of doped graphene including doping methods, doping levels, doping effect and types of heteroatoms. Very recent advances are also presented. In addition, existing problems in terms of achieving greater control over and further developments of doped graphene are also discussed. PMID:24715648

  16. Controlled cobalt doping of magnetosomes in vivo.

    PubMed

    Staniland, Sarah; Williams, Wyn; Telling, Neil; Van Der Laan, Gerrit; Harrison, Andrew; Ward, Bruce

    2008-03-01

    Magnetotactic bacteria biomineralize iron into magnetite (Fe3O4) nanoparticles that are surrounded by lipid vesicles. These 'magnetosomes' have considerable potential for use in bio- and nanotechnological applications because of their narrow size and shape distribution and inherent biocompatibility. The ability to tailor the magnetic properties of magnetosomes by chemical doping would greatly expand these applications; however, the controlled doping of magnetosomes has so far not been achieved. Here, we report controlled in vivo cobalt doping of magnetosomes in three strains of the bacterium Magnetospirillum. The presence of cobalt increases the coercive field of the magnetosomes--that is, the field necessary to reverse their magnetization--by 36-45%, depending on the strain and the cobalt content. With elemental analysis, X-ray absorption and magnetic circular dichroism, we estimate the cobalt content to be between 0.2 and 1.4%. These findings provide an important advance in designing biologically synthesized nanoparticles with useful highly tuned magnetic properties. PMID:18654488

  17. Controlled Chemical Doping of Semiconductor Nanocrystals Using Redox Buffers

    SciTech Connect

    Engel, Jesse H.; Surendranath, Yogesh; Alivisatos, Paul

    2013-07-20

    Semiconductor nanocrystal solids are attractive materials for active layers in next-generation optoelectronic devices; however, their efficient implementation has been impeded by the lack of precise control over dopant concentrations. Herein we demonstrate a chemical strategy for the controlled doping of nanocrystal solids under equilibrium conditions. Exposing lead selenide nanocrystal thin films to solutions containing varying proportions of decamethylferrocene and decamethylferrocenium incrementally and reversibly increased the carrier concentration in the solid by 2 orders of magnitude from their native values. This application of redox buffers for controlled doping provides a new method for the precise control of the majority carrier concentration in porous semiconductor thin films.

  18. Doping control analyses in horseracing: a clinician's guide.

    PubMed

    Wong, Jenny K Y; Wan, Terence S M

    2014-04-01

    Doping(1) in sports is highly detrimental, not only to the athletes involved but to the sport itself as well as to the confidence of the spectators and other participants. To protect the integrity of any sport, there must be in place an effective doping control program. In human sports, a 'top-down' and generally unified approach is taken where the rules and regulations against doping for the majority of elite sport events held in any country are governed by the World Anti-Doping Agency (WADA). However, in horseracing, there is no single organisation regulating this form of equestrian sport; instead, the rules and regulations are provided by individual racing authorities and so huge variations exist in the doping control programs currently in force around the world. This review summarises the current status of doping control analyses in horseracing, from sample collection, to the analyses of the samples, and to the need for harmonisation as well as exploring some of the difficulties currently faced by racing authorities, racing chemists and regulatory veterinarians worldwide.

  19. 12 CFR 18.1 - Purpose and OMB control number.

    Code of Federal Regulations, 2010 CFR

    2010-01-01

    ... statement with narrative information management deems important. The availability of this information is... AND OTHER INFORMATION BY NATIONAL BANKS § 18.1 Purpose and OMB control number. (a) Purpose. The... public confidence in the national banking system. (b) OMB control number. The collection of...

  20. 12 CFR 18.1 - Purpose and OMB control number.

    Code of Federal Regulations, 2012 CFR

    2012-01-01

    ... statement with narrative information management deems important. The availability of this information is... AND OTHER INFORMATION BY NATIONAL BANKS § 18.1 Purpose and OMB control number. (a) Purpose. The... public confidence in the national banking system. (b) OMB control number. The collection of...

  1. 12 CFR 18.1 - Purpose and OMB control number.

    Code of Federal Regulations, 2013 CFR

    2013-01-01

    ... statement with narrative information management deems important. The availability of this information is... AND OTHER INFORMATION BY NATIONAL BANKS § 18.1 Purpose and OMB control number. (a) Purpose. The... public confidence in the national banking system. (b) OMB control number. The collection of...

  2. 12 CFR 18.1 - Purpose and OMB control number.

    Code of Federal Regulations, 2014 CFR

    2014-01-01

    ... statement with narrative information management deems important. The availability of this information is... AND OTHER INFORMATION BY NATIONAL BANKS § 18.1 Purpose and OMB control number. (a) Purpose. The... public confidence in the national banking system. (b) OMB control number. The collection of...

  3. A steroidomic approach for biomarkers discovery in doping control.

    PubMed

    Boccard, Julien; Badoud, Flavia; Grata, Elia; Ouertani, Samia; Hanafi, Mohamed; Mazerolles, Gérard; Lantéri, Pierre; Veuthey, Jean-Luc; Saugy, Martial; Rudaz, Serge

    2011-12-10

    Anti-doping authorities have high expectations of the athlete steroidal passport (ASP) for anabolic-androgenic steroids misuse detection. However, it is still limited to the monitoring of known well-established compounds and might greatly benefit from the discovery of new relevant biomarkers candidates. In this context, steroidomics opens the way to the untargeted simultaneous evaluation of a high number of compounds. Analytical platforms associating the performance of ultra-high pressure liquid chromatography (UHPLC) and the high mass-resolving power of quadrupole time-of-flight (QTOF) mass spectrometers are particularly adapted for such purpose. An untargeted steroidomic approach was proposed to analyse urine samples from a clinical trial for the discovery of relevant biomarkers of testosterone undecanoate oral intake. Automatic peak detection was performed and a filter of reference steroid metabolites mass-to-charge ratio (m/z) values was applied to the raw data to ensure the selection of a subset of steroid-related features. Chemometric tools were applied for the filtering and the analysis of UHPLC-QTOF-MS(E) data. Time kinetics could be assessed with N-way projections to latent structures discriminant analysis (N-PLS-DA) and a detection window was confirmed. Orthogonal projections to latent structures discriminant analysis (O-PLS-DA) classification models were evaluated in a second step to assess the predictive power of both known metabolites and unknown compounds. A shared and unique structure plot (SUS-plot) analysis was performed to select the most promising unknown candidates and receiver operating characteristic (ROC) curves were computed to assess specificity criteria applied in routine doping control. This approach underlined the pertinence to monitor both glucuronide and sulphate steroid conjugates and include them in the athletes passport, while promising biomarkers were also highlighted. PMID:21831550

  4. Controlled cobalt doping in biogenic magnetite nanoparticles

    PubMed Central

    Byrne, J. M.; Coker, V. S.; Moise, S.; Wincott, P. L.; Vaughan, D. J.; Tuna, F.; Arenholz, E.; van der Laan, G.; Pattrick, R. A. D.; Lloyd, J. R.; Telling, N. D.

    2013-01-01

    Cobalt-doped magnetite (CoxFe3 −xO4) nanoparticles have been produced through the microbial reduction of cobalt–iron oxyhydroxide by the bacterium Geobacter sulfurreducens. The materials produced, as measured by superconducting quantum interference device magnetometry, X-ray magnetic circular dichroism, Mössbauer spectroscopy, etc., show dramatic increases in coercivity with increasing cobalt content without a major decrease in overall saturation magnetization. Structural and magnetization analyses reveal a reduction in particle size to less than 4 nm at the highest Co content, combined with an increase in the effective anisotropy of the magnetic nanoparticles. The potential use of these biogenic nanoparticles in aqueous suspensions for magnetic hyperthermia applications is demonstrated. Further analysis of the distribution of cations within the ferrite spinel indicates that the cobalt is predominantly incorporated in octahedral coordination, achieved by the substitution of Fe2+ site with Co2+, with up to 17 per cent Co substituted into tetrahedral sites. PMID:23594814

  5. Optimal doping control of magnetic semiconductors via subsurfactant epitaxy

    SciTech Connect

    Zeng, Changgan; Zhang, Zhenyu; van Benthem, Klaus; Chisholm, Matthew F; Weitering, Harm H

    2008-02-01

    Dilute magnetic semiconductors (DMS) with high ferromagnetic ordering temperatures (T{sub c}) have vast potential for advancing spin-based electronics or 'spintronics'. To date, achieving high-T{sub c} DMS typically required doping levels of order 5%. Such high doping levels inevitably compromise the structural homogeneity and carrier mobility of the DMS. Here, we establish 'subsurfactant epitaxy' as a novel kinetic pathway for synthesizing Mn-doped germanium with T{sub c} much higher than room temperature, at dramatically reduced doping levels. This is accomplished by optimal control of the diffusion kinetics of the dopant atoms near the growth front in two separate deposition steps. The first involves a submonolayer dose of Mn on Ge(100) at low temperature, which populates subsurface interstitial sites with Mn while suppressing lateral Mn diffusion and clustering. The second step involves epitaxial growth of Ge at elevated temperature, taking advantage of the strong floating ability of the interstitial Mn dopants towards the newly defined subsurface sites at the growth front. Most remarkably, the Mn dopants trapped inside the film are uniformly distributed at substitutional sites, and the resulting film exhibits ferromagnetism above 400 K at the nominal doping level of only 0.2%.

  6. RoboCon: A general purpose telerobotic control center

    SciTech Connect

    Draper, J.V.; Noakes, M.W.; Schempf, H.; Blair, L.M.

    1997-02-01

    This report describes human factors issues involved in the design of RoboCon, a multi-purpose control center for use in US Department of Energy remote handling applications. RoboCon is intended to be a flexible, modular control center capable of supporting a wide variety of robotic devices.

  7. Perceptually controlled doping for audio source separation

    NASA Astrophysics Data System (ADS)

    Mahé, Gaël; Nadalin, Everton Z.; Suyama, Ricardo; Romano, João MT

    2014-12-01

    The separation of an underdetermined audio mixture can be performed through sparse component analysis (SCA) that relies however on the strong hypothesis that source signals are sparse in some domain. To overcome this difficulty in the case where the original sources are available before the mixing process, the informed source separation (ISS) embeds in the mixture a watermark, which information can help a further separation. Though powerful, this technique is generally specific to a particular mixing setup and may be compromised by an additional bitrate compression stage. Thus, instead of watermarking, we propose a `doping' method that makes the time-frequency representation of each source more sparse, while preserving its audio quality. This method is based on an iterative decrease of the distance between the distribution of the signal and a target sparse distribution, under a perceptual constraint. We aim to show that the proposed approach is robust to audio coding and that the use of the sparsified signals improves the source separation, in comparison with the original sources. In this work, the analysis is made only in instantaneous mixtures and focused on voice sources.

  8. Speed Control of General Purpose Engine with Electronic Governor

    NASA Astrophysics Data System (ADS)

    Sawut, Umerujan; Tohti, Gheyret; Takigawa, Buso; Tsuji, Teruo

    This paper presents a general purpose engine speed control system with an electronic governor in order to improve the current system with a mechanical governor which shows unstable characteristics by change of mecanical friction or A/F ratio (Air/Fuel ratio). For the control system above, there are problems that the feedback signal is only a crank angle because of cost and the controlled object is a general purpose engine which is strongly nonlinear. In order to overcome these problems, the system model is shown for the dynamic estimation of the amount of air flow and the robust controller is designed. That is, the proposed system includes the robust sliding-mode controller by the feedback signal of only a crank angle where Genetic Algorithm is applied for the controller design. The simulation and the experiments by MATLAB/Simulink are performed to show the effectiveness of our proposal.

  9. General-Purpose Serial Interface For Remote Control

    NASA Technical Reports Server (NTRS)

    Busquets, Anthony M.; Gupton, Lawrence E.

    1990-01-01

    Computer controls remote television camera. General-purpose controller developed to serve as interface between host computer and pan/tilt/zoom/focus functions on series of automated video cameras. Interface port based on 8251 programmable communications-interface circuit configured for tristated outputs, and connects controller system to any host computer with RS-232 input/output (I/O) port. Accepts byte-coded data from host, compares them with prestored codes in read-only memory (ROM), and closes or opens appropriate switches. Six output ports control opening and closing of as many as 48 switches. Operator controls remote television camera by speaking commands, in system including general-purpose controller.

  10. Doping Level of Boron-Doped Diamond Electrodes Controls the Grafting Density of Functional Groups for DNA Assays.

    PubMed

    Švorc, Ĺubomír; Jambrec, Daliborka; Vojs, Marian; Barwe, Stefan; Clausmeyer, Jan; Michniak, Pavol; Marton, Marián; Schuhmann, Wolfgang

    2015-09-01

    The impact of different doping levels of boron-doped diamond on the surface functionalization was investigated by means of electrochemical reduction of aryldiazonium salts. The grafting efficiency of 4-nitrophenyl groups increased with the boron levels (B/C ratio from 0 to 20,000 ppm). Controlled grafting of nitrophenyldiazonium was used to adjust the amount of immobilized single-stranded DNA strands at the surface and further on the hybridization yield in dependence on the boron doping level. The grafted nitro functions were electrochemically reduced to the amine moieties. Subsequent functionalization with a succinic acid introduced carboxyl groups for subsequent binding of an amino-terminated DNA probe. DNA hybridization significantly depends on the probe density which is in turn dependent on the boron doping level. The proposed approach opens new insights for the design and control of doped diamond surface functionalization for the construction of DNA hybridization assays.

  11. Investigation of the in vitro metabolism of the emerging drug candidate S107 for doping-preventive purposes.

    PubMed

    Beuck, S; Schänzer, W; Thevis, M

    2011-02-01

    The metabolic fate of the emerging drug candidate S107, possessing the potential for misuse as performance-enhancing agent in sports, was investigated by in vitro phase I and II experiments with human microsomal and S9 liver enzymes. The metabolites were identified by liquid chromatography-mass spectrometry with electrospray ionisation in positive mode (LC-ESI-MS/MS). Their collision-induced dissociation behaviour was studied by high-resolution/high accuracy Orbitrap MS(n) analysis, supported by stable isotope labelling, H/D-exchange experiments and density functional theory calculations. Monooxygenation accounted for the main phase I metabolic transformation due to N- and S-oxidation of the 1,4-benzothiazepine core, as substantiated by chemical synthesis, selective reduction methods and characteristic APCI in source fragmentation behaviour of the metabolites. Another dominant metabolic pathway was demethylation, yielding the N- and O-demethylated metabolite, respectively. The latter was further conjugated by glucuronidation as well as sulfonation in subsequent phase II metabolic reactions, whereas the N-demethylated metabolite was not amenable to conjugation. The active drug molecule itself was converted to two glucuronic acid conjugates, which are proposed to consist of two quaternary S107-N(+)-glucuronide isomers. All glucuronides were susceptible to enzymatic hydrolysis with β-glucuronidase (Escherichia coli). A comprehensive LC-ESI-MS(/MS)-based detection method for urine was developed and its fitness for purpose was assessed. The assay can serve as a potential screening and/or confirmation method for S107 in clinical drug testing and doping control analysis in the future. PMID:21254313

  12. Development of a General Purpose Power System Control Board

    SciTech Connect

    Nam, S.H.; Jeong, S.H.; Kim, S.H.; Kim, S.C.; Park, S.S.; Suh, J.H.; Bellomo, P.; Cassel, R.; Larsen, R.; Nguyen, M.N.; /SLAC

    2007-07-23

    In an effort to control modern solid state power modules, a general purpose, multi function power system control board (PSCB) has been under development as a collaboration project between Pohang Accelerator Laboratory (PAL), Korea, and Stanford Linear Accelerator Center (SLAC), USA. The PSCB is an embedded, interlock supervisory, diagnostic, timing, and set-point control board. It is designed to use in various power systems such as sequenced kicker pulsers, solid state RF modulators, simple DC magnet power supplies, etc. The PSCB has the Ethernet communication with the TCP/IP Modbus protocol.

  13. The purposes, achievements, and priorities of arms control

    SciTech Connect

    Brown, P.S.

    1987-09-01

    Arms control purposes include strengthening the framework of deterrence and reducing the threat of the use of nuclear weapons, reducing the dangers of attack and accidental nuclear war, and allowing more resources for the civilian economy. The paper briefly describes achievements in arms control since World War II. These include the Limited Test Ban Treaty (LTBT), Nonproliferation Treaty (NPT), Anti-Ballistic Missile Treaty (ABMT)-SALT I, SALT II, Threshold Test Ban Treaty (TTBT), Peaceful Nuclear Explosions Treaty (PNET), and Nuclear-Free Zones treaties. The author also discusses his views on what the priorities of arms control activities should be. (ACR)

  14. [Doping in disabled sports. Doping control activities at the Paralympic Games 1984-2008 and in Germany 1992-2008].

    PubMed

    Thevis, Mario; Hemmersbach, Peter; Geyer, Hans; Schänzer, Wilhelm

    2009-12-15

    Activities concerning the fight against doping with regard to the Paralympic Games have been initiated in 1984, when first doping controls were conducted. The foundation of the International Paralympic Committee exactly 20 years ago (1989) considerably supported systematic sports drug-testing programs specifically designed to meet the particular challenges related to disabled sports, which yielded a variety of adverse analytical findings (e.g., with anabolic steroids, diuretics, corticosteroids, and stimulants) especially at Paralympic Summer Games. In Germany, doping controls for handicapped athletes were established in 1992 and have been conducted since by the National Paralympic Committee Germany and the National Anti-Doping Agency. Also here, various analogies in terms of antidoping rule violations were found in comparison to doping controls of nondisabled athletes. In the present article, available numbers of samples analyzed at Paralympic Summer and Winter Games as well as within the doping control program for disabled sports in Germany are summarized, and particularities concerning sample collection and the doping method termed boosting are presented.

  15. Purpose in life, depression, and locus of control.

    PubMed

    Phillips, W M

    1980-07-01

    Parallel to Frankl's theory of the search for meaning, which posits the separateness but intertwining of the psychological and existential realms, the Purpose In Life Test (PIL) has been found to have a low to moderate relationship with most conceptually related psychological measures. Extending separate correlational studies of the PIL with depression and locus of control, the current study inspected the relationship of individual PIL items to groups formed according to Zung Self-Rating Depression Scale and Rotter Internal-External Locus Of Control scores. One-hundred thirty-four Ss were split into four groups: Depressed external, depressed internals, nondepressed externals, and nondepressed internals. Although ungrouped correlational analysis of PIL items revealed only seven significant relationships with depression and two with locus of control, multiple discriminate analysis was successful in correctly classifying depressed externals about three-fourths of the time, and the overall "hit rate" for the four groups was above 60%. In addition to further validating the interaction of purpose in life with related psychological and social expectancy variables, results indicated a compounding effect between depression and external perception of reinforcement control with PIL scores in general, and two items (#4, 12) in particular, which appear to reflect the experience of current congruent involvement between the individual and his world.

  16. Charge-controlled magnetism in colloidal doped semiconductor nanocrystals

    NASA Astrophysics Data System (ADS)

    Gamelin, Daniel

    2010-03-01

    Electrical control over the magnetic states of doped semiconductor nanostructures could enable new spin-based information processing technologies, but the relatively weak interactions between dopants and charge carriers have so far suggested that such gated magnetism will be limited to cryogenic temperatures. This talk will describe the observation of a large, reversible, room-temperature magnetic response to charge injection in free-standing colloidal ZnO nanocrystals doped with Mn(II) ions. Injected electrons are found to delocalize throughout the entire nanocrystal, and to activate new ferromagnetic Mn(II)-Mn(II) exchange interactions that are strong enough to overcome antiferromagnetic coupling between nearest-neighbor Mn(II) ions, making the full magnetic moments of all dopants observable upon charging. Removal of the electron causes the system to revert to its original form, allowing reversible charge-controlled manipulation of room-temperature nanocrystal magnetism. The physical properties of these charged, doped nanocrystals are directly analogous to those of bound magnetic poltroons (BMPs) postulated to underlie high-temperature ferromagnetic ordering in the bulk forms of this and related diluted magnetic oxides. This discovery of charge-controlled magnetism in free-standing colloidal nanocrystals that is large, reversible, and stable at room temperature presents new opportunities for fundamental studies and raises interesting possibilities for the development of spin-based information processing technologies from solution-processable semiconductor nanostructures. Related references: Ochsenbein, S. T.; Feng, Y.; Whitaker, K. M.; Badaeva, E.; Liu, W. K.; Li, X.; Gamelin, D. R., Nature Nanotechnology, 4, 681 (2009); Liu, W. K.; Whitaker, K. M.; Kittilstved, K. R.; Gamelin, D. R., J. Am. Chem. Soc., 128, 3910 (2006).

  17. Process Control in Production-Worthy Plasma Doping Technology

    SciTech Connect

    Winder, Edmund J.; Fang Ziwei; Arevalo, Edwin; Miller, Tim; Persing, Harold; Singh, Vikram; Parrill, T. M.

    2006-11-13

    As the semiconductor industry continues to scale devices of smaller dimensions and improved performance, many ion implantation processes require lower energy and higher doses. Achieving these high doses (in some cases {approx}1x1016 ions/cm2) at low energies (<3 keV) while maintaining throughput is increasingly challenging for traditional beamline implant tools because of space-charge effects that limit achievable beam density at low energies. Plasma doping is recognized as a technology which can overcome this problem. In this paper, we highlight the technology available to achieve process control for all implant parameters associated with modem semiconductor manufacturing.

  18. Determining the authenticity of athlete urine in doping control by DNA analysis.

    PubMed

    Devesse, Laurence; Syndercombe Court, Denise; Cowan, David

    2015-10-01

    The integrity of urine samples collected from athletes for doping control is essential. The authenticity of samples may be contested, leading to the need for a robust sample identification method. DNA typing using short tandem repeats (STR) can be used for identification purposes, but its application to cellular DNA in urine has so far been limited. Here, a reliable and accurate method is reported for the successful identification of urine samples, using reduced final extraction volumes and the STR multiplex kit, Promega® PowerPlex ESI 17, with capillary electrophoretic characterisation of the alleles. Full DNA profiles were obtained for all samples (n = 20) stored for less than 2 days at 4 °C. The effect of different storage conditions on yield of cellular DNA and probability of obtaining a full profile were also investigated. Storage for 21 days at 4 °C resulted in allelic drop-out in some samples, but the random match probabilities obtained demonstrate the high power of discrimination achieved through targeting a large number of STRs. The best solution for long-term storage was centrifugation and removal of supernatant prior to freezing at -20 °C. The method is robust enough for incorporation into current anti-doping protocols, and was successfully applied to 44 athlete samples for anti-doping testing with 100% concordant typing.

  19. Control performance and biomembrane disturbance of carbon nanotube artificial water channels by nitrogen-doping.

    PubMed

    Yang, Yuling; Li, Xiaoyi; Jiang, Jinliang; Du, Huailiang; Zhao, Lina; Zhao, Yuliang

    2010-10-26

    To establish ways to control the performance of artificial water channels is a big challenge. With molecular dynamics studies, we found that water flow inside the water channels of carbon nanotubes (CNTs) can be controlled by reducing or intensifying interaction energy between water molecules and the wall of the CNTs channel. A way of example toward this significant goal was demonstrated by the doping of nitrogen into the wall of CNTs. Different ratios of nitrogen doping result in different controllable water performance which is dominated mainly through a gradient of van der Waals forces created by the heteroatom doping in the wall of CNTs. Further results revealed that the nitrogen-doped CNT channels show less influence on the integrality of biomembrane than the pristine one, while the nitrogen-doped double-walled carbon nanotube exhibits fewer disturbances to the cellular membrane integrality than the nitrogen-doped single-walled carbon nanotube when interacting with biomembranes.

  20. Humane killing of animals for disease control purposes.

    PubMed

    Thornber, P M; Rubira, R J; Styles, D K

    2014-04-01

    Killing for disease control purposes is an emotional issue for everyone concerned. Large-scale euthanasia or depopulation of animals may be necessary for the emergency control or eradication of animal diseases, to remove animals from a compromised situation (e.g. following flood, storm, fire, drought or a feed contamination event), to effect welfare depopulation when there is an oversupply due to a dysfunctional or closed marketing channel, or to depopulate and dispose of animals with minimal handling to decrease the risk of a zoonotic disease infecting humans. The World Organisation for Animal Health (OIE) developed international standards to provide advice on humane killing for various species and situations. Some fundamental issues are defined, such as competency of animal handling and implementation of humane killing techniques. Some of these methods have been used for many years, but novel approaches for the mass killing of particular species are being explored. Novel vaccines and new diagnostic techniques that differentiate between vaccinated and infected animals will save many animals from being killed as part of biosecurity response measures. Unfortunately, the destruction of affected livestock will still be required to control diseases whilst vaccination programmes are activated or where effective vaccines are not available. This paper reviews the principles of humane destruction and depopulation and explores available techniques with their associated advantages and disadvantages. It also identifies some current issues that merit consideration, such as legislative conflicts (emergency disease legislation versus animal welfare legislation, occupational health and safety), media issues, opinions on the future approaches to killing for disease control, and animal welfare.

  1. Humane killing of animals for disease control purposes.

    PubMed

    Thornber, P M; Rubira, R J; Styles, D K

    2014-04-01

    Killing for disease control purposes is an emotional issue for everyone concerned. Large-scale euthanasia or depopulation of animals may be necessary for the emergency control or eradication of animal diseases, to remove animals from a compromised situation (e.g. following flood, storm, fire, drought or a feed contamination event), to effect welfare depopulation when there is an oversupply due to a dysfunctional or closed marketing channel, or to depopulate and dispose of animals with minimal handling to decrease the risk of a zoonotic disease infecting humans. The World Organisation for Animal Health (OIE) developed international standards to provide advice on humane killing for various species and situations. Some fundamental issues are defined, such as competency of animal handling and implementation of humane killing techniques. Some of these methods have been used for many years, but novel approaches for the mass killing of particular species are being explored. Novel vaccines and new diagnostic techniques that differentiate between vaccinated and infected animals will save many animals from being killed as part of biosecurity response measures. Unfortunately, the destruction of affected livestock will still be required to control diseases whilst vaccination programmes are activated or where effective vaccines are not available. This paper reviews the principles of humane destruction and depopulation and explores available techniques with their associated advantages and disadvantages. It also identifies some current issues that merit consideration, such as legislative conflicts (emergency disease legislation versus animal welfare legislation, occupational health and safety), media issues, opinions on the future approaches to killing for disease control, and animal welfare. PMID:25000803

  2. Programming methodology for a general purpose automation controller

    NASA Technical Reports Server (NTRS)

    Sturzenbecker, M. C.; Korein, J. U.; Taylor, R. H.

    1987-01-01

    The General Purpose Automation Controller is a multi-processor architecture for automation programming. A methodology has been developed whose aim is to simplify the task of programming distributed real-time systems for users in research or manufacturing. Programs are built by configuring function blocks (low-level computations) into processes using data flow principles. These processes are activated through the verb mechanism. Verbs are divided into two classes: those which support devices, such as robot joint servos, and those which perform actions on devices, such as motion control. This programming methodology was developed in order to achieve the following goals: (1) specifications for real-time programs which are to a high degree independent of hardware considerations such as processor, bus, and interconnect technology; (2) a component approach to software, so that software required to support new devices and technologies can be integrated by reconfiguring existing building blocks; (3) resistance to error and ease of debugging; and (4) a powerful command language interface.

  3. Self-control, self-regulation, and doping in sport: a test of the strength-energy model.

    PubMed

    Chan, Derwin K; Lentillon-Kaestner, Vanessa; Dimmock, James A; Donovan, Robert J; Keatley, David A; Hardcastle, Sarah J; Hagger, Martin S

    2015-04-01

    We applied the strength-energy model of self-control to understand the relationship between self-control and young athletes' behavioral responses to taking illegal performance-enhancing substances, or "doping." Measures of trait self-control, attitude and intention toward doping, intention toward, and adherence to, doping-avoidant behaviors, and the prevention of unintended doping behaviors were administered to 410 young Australian athletes. Participants also completed a "lollipop" decision-making protocol that simulated avoidance of unintended doping. Hierarchical linear multiple regression analyses revealed that self-control was negatively associated with doping attitude and intention, and positively associated with the intention and adherence to doping-avoidant behaviors, and refusal to take or eat the unfamiliar candy offered in the "lollipop" protocol. Consistent with the strength-energy model, athletes with low self-control were more likely to have heightened attitude and intention toward doping, and reduced intention, behavioral adherence, and awareness of doping avoidance.

  4. BLASTbus electronics: general-purpose readout and control for balloon-borne experiments

    NASA Astrophysics Data System (ADS)

    Benton, S. J.; Ade, P. A.; Amiri, M.; Angilè, F. E.; Bock, J. J.; Bond, J. R.; Bryan, S. A.; Chiang, H. C.; Contaldi, C. R.; Crill, B. P.; Devlin, M. J.; Dober, B.; Doré, O. P.; Farhang, M.; Filippini, J. P.; Fissel, L. M.; Fraisse, A. A.; Fukui, Y.; Galitzki, N.; Gambrel, A. E.; Gandilo, N. N.; Golwala, S. R.; Gudmundsson, J. E.; Halpern, M.; Hasselfield, M.; Hilton, G. C.; Holmes, W. A.; Hristov, V. V.; Irwin, K. D.; Jones, W. C.; Kermish, Z. D.; Klein, J.; Korotkov, A. L.; Kuo, C. L.; MacTavish, C. J.; Mason, P. V.; Matthews, T. G.; Megerian, K. G.; Moncelsi, L.; Morford, T. A.; Mroczkowski, T. K.; Nagy, J. M.; Netterfield, C. B.; Novak, G.; Nutter, D.; O'Brient, R.; Ogburn, R. W.; Pascale, E.; Poidevin, F.; Rahlin, A. S.; Reintsema, C. D.; Ruhl, J. E.; Runyan, M. C.; Savini, G.; Scott, D.; Shariff, J. A.; Soler, J. D.; Thomas, N. E.; Trangsrud, A.; Truch, M. D.; Tucker, C. E.; Tucker, G. S.; Tucker, R. S.; Turner, A. D.; Ward-Thompson, D.; Weber, A. C.; Wiebe, D. V.; Young, E. Y.

    2014-07-01

    We present the second generation BLASTbus electronics. The primary purposes of this system are detector readout, attitude control, and cryogenic housekeeping, for balloon-borne telescopes. Readout of neutron transmutation doped germanium (NTD-Ge) bolometers requires low noise and parallel acquisition of hundreds of analog signals. Controlling a telescope's attitude requires the capability to interface to a wide variety of sensors and motors, and to use them together in a fast, closed loop. To achieve these different goals, the BLASTbus system employs a flexible motherboard-daughterboard architecture. The programmable motherboard features a digital signal processor (DSP) and field-programmable gate array (FPGA), as well as slots for three daughterboards. The daughterboards provide the interface to the outside world, with versions for analog to digital conversion, and optoisolated digital input/output. With the versatility afforded by this design, the BLASTbus also finds uses in cryogenic, thermometry, and power systems. For accurate timing control to tie everything together, the system operates in a fully synchronous manner. BLASTbus electronics have been successfully deployed to the South Pole, and own on stratospheric balloons.

  5. Mini All-purpose Satellite Control Center (MASCC)

    NASA Technical Reports Server (NTRS)

    Zaouche, Gerard

    1994-01-01

    A new generation of Mini All-purpose Satellite Control Centers (MASCC) has been developed by CNES (F). They turn out to be easily adaptable to different kinds of satellites, both Low Earth Orbital or Geostationary. The features of MASCC allow both standard satellite control activities, and checking of passengers experiments hosted on a space platform. In the different environments in which it may be used, MASCC provides standard broadcasting of telemetry parameters on animated synoptics (curves, bar graphs, alphanumeric displays, ...), which turns out to be a very useful and ergonomic medium for operational teams or satellite specialists. Special care has been taken during the MASCC development about two points: - automation of all routine tasks, allowing automated operation, and limiting human commitment to system supervision and decision making, - software adaptability. To reach these two main objectives, the MASCC design provides:(1) a simple, robust and flexible hardware architecture, based on powerful distributed workstations; and (2) a table-driven software architecture, easily adapted to various operational needs. Satellite characteristics are described in a central Data Base. Hence, the processing of telemetry and commands is largely independent from the satellite itself. In order to validate these capabilities, the MASCC has been customized to several types of satellites and orbital platforms: (1) SPOT4, the French new generation of remote sensing satellites; (2) TELECOM2, the French geostationary TV and telecommunication satellite; and (3) MIR, the Russian orbital platform. MASCC development has been completed by the third quarter of 1993. This paper will provide first a description of the MASCC basic functions, of its hardware and software design. It will then detail the increased automation capability, along with the easy adaptation of the MASCC to new satellites with minimal software modifications.

  6. Rogue athletes and recombinant DNA technology: challenges for doping control.

    PubMed

    Azzazy, Hassan M E; Mansour, Mai M H

    2007-10-01

    The quest for athletic excellence holds no limit for some athletes, and the advances in recombinant DNA technology have handed these athletes the ultimate doping weapons: recombinant proteins and gene doping. Some detection methods are now available for several recombinant proteins that are commercially available as pharmaceuticals and being abused by dopers. However, researchers are struggling to come up with efficient detection methods in preparation for the imminent threat of gene doping, expected in the 2008 Olympics. This Forum article presents the main detection strategies for recombinant proteins and the forthcoming detection strategies for gene doping as well as the prime analytical challenges facing them.

  7. Control of work function of graphene by plasma assisted nitrogen doping

    SciTech Connect

    Akada, Keishi; Terasawa, Tomo-o; Imamura, Gaku; Obata, Seiji; Saiki, Koichiro

    2014-03-31

    Nitrogen doping is expected to provide several intriguing properties to graphene. Nitrogen plasma treatment to defect-free and defective highly oriented pyrolytic graphite (HOPG) samples causes doping of nitrogen atom into the graphene layer. Nitrogen atoms are initially doped at a graphitic site (inside the graphene) for the defect-free HOPG, while doping to a pyridinic or a pyrrolic site (edge of the graphene) is dominant for the defective HOPG. The work function of graphene correlates strongly with the site and amount of doped nitrogen. Nitrogen atoms doped at a graphitic site lower the work function, while nitrogen atoms at a pyridinic or a pyrrolic site increase the work function. Control of plasma treatment time and the amount of initial defect could change the work function of graphite from 4.3 eV to 5.4 eV, which would open a way to tailor the nature of graphene for various industrial applications.

  8. Screening for the synthetic cannabinoid JWH-018 and its major metabolites in human doping controls.

    PubMed

    Möller, Ines; Wintermeyer, Annette; Bender, Katja; Jübner, Martin; Thomas, Andreas; Krug, Oliver; Schänzer, Wilhelm; Thevis, Mario

    2011-09-01

    Referred to as 'spice', several new drugs, advertised as herbal blends, have appeared on the market in the last few years, in which the synthetic cannabinoids JWH-018 and a C(8) homologue of CP 47,497 were identified as major active ingredients. Due to their reported cannabis-like effects, many European countries have banned these substances. The World Anti-Doping Agency has also explicitly prohibited synthetic cannabinoids in elite sport in-competition. Since urine specimens have been the preferred doping control samples, the elucidation of the metabolic pathways of these substances is of particular importance to implement them in sports drug testing programmes. In a recent report, an in vitro phase-I metabolism study of JWH-018 was presented yielding mainly hydroxylated and N-dealkylated metabolites. Due to these findings, a urine sample of a healthy man declaring to have smoked a 'spice' product was screened for potential phase-I and -II metabolites by high-resolution/high-accuracy mass spectrometry in the present report. The majority of the phase-I metabolites observed in earlier in vitro studies of JWH-018 were detected in this urine specimen and furthermore most of their respective monoglucuronides. As no intact JWH-018 was detectable, the monohydroxylated metabolite being the most abundant one was chosen as a target analyte for sports drug testing purposes; a detection method was subsequently developed and validated in accordance to conventional screening protocols based on enzymatic hydrolysis, liquid-liquid extraction, and liquid chromatography/electrospray tandem mass spectrometry analysis. The method was applied to approximately 7500 urine doping control samples yielding two JWH-018 findings and demonstrated its capability for a sensitive and selective identification of JWH-018 and its metabolites in human urine.

  9. Is there a place for hair analysis in doping controls?

    PubMed

    Rivier, L

    2000-01-10

    The actual antidoping control rules applied in sports (as established by the International Olympic Committee and the International Sport Federations) state that a positive case is chemically established by the unequivocal detection of a forbidden parent molecule and/or any of its metabolite(s) in urine, no matter the amounts which were administered and when the drug was taken. Screening is accomplished most of the time by using GC-MS procedures. These have been optimized to detect most if not all of the forbidden compounds which are put on a list. Recently, attempts have been made on scalp hair to demonstrate the value of this matrix as a possible means for differentiating between therapeutic use and doping abuse. In particular, GC-mass selective detector and GC-high resolution MS were successfully applied to treated animals and body-builders for anabolic agents (steroids and beta-2-agonists) at high sensitivity detection (low ng/g level). Naturally occurring molecules, like testosterone and its metabolites, could also be differentiated from their synthetic counterparts. Positive cases are more often challenged in courts and retrospectivity in time of the drug(s) intake is becoming an important issue for evaluating the responsibility of the person. This is can be based on hair analyses if the drugs have been taken at regular intervals. Stimulants and narcotics are often used in sports like drug of abuse in the ordinary social contexts. On the other hand, anabolic agents, when taken to improve the physical performances, follow complex regimens with the mixing of various formulas and dosages. Scalp hair references ranges for these as well as for endogenous substances still wait to be established statistically for competing, well-trained athletes. The incorporation rate into blond or gray hair is poorer than that of dark colored hair raising the question of individuals equality against the controls, a very important matter of concern for the sport's governing bodies

  10. A call for policy guidance on psychometric testing in doping control in sport.

    PubMed

    Petróczi, Andrea; Backhouse, Susan H; Barkoukis, Vassilis; Brand, Ralf; Elbe, Anne-Marie; Lazuras, Lambros; Lucidi, Fabio

    2015-11-01

    One of the fundamental challenges in anti-doping is identifying athletes who use, or are at risk of using, prohibited performance enhancing substances. The growing trend to employ a forensic approach to doping control aims to integrate information from social sciences (e.g., psychology of doping) into organised intelligence to protect clean sport. Beyond the foreseeable consequences of a positive identification as a doping user, this task is further complicated by the discrepancy between what constitutes a doping offence in the World Anti-Doping Code and operationalized in doping research. Whilst psychology plays an important role in developing our understanding of doping behaviour in order to inform intervention and prevention, its contribution to the array of doping diagnostic tools is still in its infancy. In both research and forensic settings, we must acknowledge that (1) socially desirable responding confounds self-reported psychometric test results and (2) that the cognitive complexity surrounding test performance means that the response-time based measures and the lie detector tests for revealing concealed life-events (e.g., doping use) are prone to produce false or non-interpretable outcomes in field settings. Differences in social-cognitive characteristics of doping behaviour that are tested at group level (doping users vs. non-users) cannot be extrapolated to individuals; nor these psychometric measures used for individual diagnostics. In this paper, we present a position statement calling for policy guidance on appropriate use of psychometric assessments in the pursuit of clean sport. We argue that, to date, both self-reported and response-time based psychometric tests for doping have been designed, tested and validated to explore how athletes feel and think about doping in order to develop a better understanding of doping behaviour, not to establish evidence for doping. A false 'positive' psychological profile for doping affects not only the individual

  11. A call for policy guidance on psychometric testing in doping control in sport.

    PubMed

    Petróczi, Andrea; Backhouse, Susan H; Barkoukis, Vassilis; Brand, Ralf; Elbe, Anne-Marie; Lazuras, Lambros; Lucidi, Fabio

    2015-11-01

    One of the fundamental challenges in anti-doping is identifying athletes who use, or are at risk of using, prohibited performance enhancing substances. The growing trend to employ a forensic approach to doping control aims to integrate information from social sciences (e.g., psychology of doping) into organised intelligence to protect clean sport. Beyond the foreseeable consequences of a positive identification as a doping user, this task is further complicated by the discrepancy between what constitutes a doping offence in the World Anti-Doping Code and operationalized in doping research. Whilst psychology plays an important role in developing our understanding of doping behaviour in order to inform intervention and prevention, its contribution to the array of doping diagnostic tools is still in its infancy. In both research and forensic settings, we must acknowledge that (1) socially desirable responding confounds self-reported psychometric test results and (2) that the cognitive complexity surrounding test performance means that the response-time based measures and the lie detector tests for revealing concealed life-events (e.g., doping use) are prone to produce false or non-interpretable outcomes in field settings. Differences in social-cognitive characteristics of doping behaviour that are tested at group level (doping users vs. non-users) cannot be extrapolated to individuals; nor these psychometric measures used for individual diagnostics. In this paper, we present a position statement calling for policy guidance on appropriate use of psychometric assessments in the pursuit of clean sport. We argue that, to date, both self-reported and response-time based psychometric tests for doping have been designed, tested and validated to explore how athletes feel and think about doping in order to develop a better understanding of doping behaviour, not to establish evidence for doping. A false 'positive' psychological profile for doping affects not only the individual

  12. Control of Rewriteable Doping Patterns in Graphene/Boron Nitride Heterostructures

    NASA Astrophysics Data System (ADS)

    Kahn, Salman; Velasco, Jairo, Jr.; Wong, Dillon; Lee, Juwon; Tsai, Hsin Zon; Ju, Long; Jiang, Lili; Shi, Zhiwen; Ashby, Paul; Taniguchi, Takashi; Watanabe, Kenji; Zettl, Alex; Wang, Feng; Crommie, Michael

    Spatial control of charge doping in 2D materials is a promising technique for designing future electronic devices and understanding novel physics. Electrostatic gating and chemical doping are common methods to achieve control of charge doping in 2D materials. However, these approaches suffer from complicated fabrication processes that introduce impurities, change material properties irreversibly, and lack flexibility. Here, we introduce a new method for patterning rewriteable doping profiles with local interface charge transfer from defects in a tunable BN substrate into an adjacent layer of graphene. We characterize these spatial doping patterns through local probe and transport techniques. This technique enables many novel device designs for 2D materials, including atomically thin p-n junctions and rewriteable memory devices.

  13. Base doping and dopant profile control of SiGe npn and pnp HBTs

    NASA Astrophysics Data System (ADS)

    Tillack, Bernd; Heinemann, Bernd; Knoll, Dieter; Rücker, Holger; Yamamoto, Yuji

    2008-07-01

    Incorporation of high doping concentrations and the creation and maintaining of steep doping profiles during processing are key enabler for high level RF performance of heterojunction bipolar transistors (HBTs). In this paper, we discuss results of base doping and dopant profile control for npn and pnp SiGe HBTs fabricated within 0.25 μm BiCMOS technologies. High level of electrically active B and P doping concentrations (up to 10 20 cm -3) have been incorporated into SiGe. By adding C to SiGe steep doping profiles have been maintained due to the prevention of dopant diffusion during device processing. It is shown that broadening of P doping profiles caused by segregation could be reduced by lowering the deposition temperature for the SiGe cap. B and P atomic layer doping is shown to be suitable for the creation of steep and narrow doping profiles. This result is demonstrating the capability of the atomic layer processing approach for future devices with critical requirements of dopant dose and location control.

  14. Detection of prohibited substances by liquid chromatography tandem mass spectrometry for sports doping control.

    PubMed

    Ahrens, Brian D; Starcevic, Borislav; Butch, Anthony W

    2012-01-01

    Drug testing for sports doping control programs is extensive and includes numerous classes of banned compounds including anabolic androgenic steroids, β2-agonists, hormone antagonists and modulators, diuretics, various peptide hormones, and growth factors. During competition, additional compounds may also be prohibited such as stimulants, narcotics, cannabinoids, glucocorticosteroids, and beta-blockers depending both on the sport and level of competition. Each of these classes of compounds can contain many prohibited substances that must be identified during the testing procedure. Various methods that have been designed to detect a large number of compounds in different drug classes are highly desirable as initial screening tools. Liquid chromatography/tandem mass spectrometry (LC-MS/MS) is widely used by anti-doping testing laboratories for this purpose and several rapid methods have been described to simultaneously detect different classes of compounds. Here, we describe a simple urine sample cleanup procedure that can be used to detect numerous anabolic androgenic steroids, β2-agonists, hormone antagonists and modulators, glucocorticosteroids, and beta-blockers by LC-MS/MS.

  15. Controlled release of alendronate from nitrogen-doped mesoporous carbon

    DOE PAGES

    Saha, Dipendu; Spurri, Amanda; Chen, Jihua; Hensley, Dale K.

    2016-04-13

    With this study, we have synthesized a nitrogen doped mesoporous carbon with the BET surface area of 1066 m2/g, total pore volume 0.6 cm3/g and nitrogen content of 0.5%. Total alendronate adsorption in this carbon was ~5%. The release experiments were designed in four different media with sequential pH values of 1.2, 4.5, 6.8 and 7.4 for 3, 1, 3 and 5 h, respectively and at 37 °C to imitate the physiological conditions of stomach, duodenum, small intestine and colon, respectively. Release of the drug demonstrated a controlled fashion; only 20% of the drug was released in the media withmore » pH = 1.2, whereas 64% of the drug was released in pH = 7.4. This is in contrary to pure alendronate that was completely dissolved within 30 min in the first release media (pH = 1.2) only. The relatively larger uptake of alendronate in this carbon and its sustained fashion of release can be attributed to the hydrogen bonding between the drug and the nitrogen functionalities on carbon surface. Based on this result, it can be inferred that this formulation may lower the side effects of oral delivery of alendronate.« less

  16. Use of General Purpose Microcomputers in a Digital Control Course.

    ERIC Educational Resources Information Center

    Petersen, James N.; Cavalieri, Ralph

    1984-01-01

    Describes a relatively inexpensive system which allows students in a digital control course hands-on experience in the implementation of control algorithms on a variety of processes. The system uses two computers, one for real time simulation of the process and the other for implementation of the digital control algorithms. (JN)

  17. All-purpose bidirectional four-quadrant controller

    NASA Technical Reports Server (NTRS)

    Hansen, I. G.

    1983-01-01

    The basic purpose of this paper is to provide some information regarding bidirectional four quadrant resonant power conversion and describe possible applications to aircraft electrical systems. As this technology has been developed sufficiently to demonstrate its feasibility, this is an appropriate time to evaluate the benefits of its application to aircraft electrical systems.

  18. Controlling ferromagnetism of (In,Fe)As semiconductors by electron doping

    SciTech Connect

    Dang Vu, Nguyen; Fukushima, Tetsuya; Katayama-Yoshida, Hiroshi; Sato, Kazunori

    2014-02-21

    Based on experimental results, using the Korringa-Kohn-Rostoker coherent potential approximation (KKR-CPA) method and Monte Carlo simulation, we study the mechanism of ferromagnetic behavior of (In,Fe)As. We show that with doped Be atoms occupying in interstitial sites, chemical pair interactions between atoms and magnetic exchange interactions between Fe atoms change due to electron concentration. Therefore, by controlling the doping process, magnetic behavior of (In,Fe)As is controlled and ferromagnetism is observed in this semiconductor.

  19. Tailoring the optical bandgap and magnetization of cobalt ferrite thin films through controlled zinc doping

    NASA Astrophysics Data System (ADS)

    Sharma, Deepanshu; Khare, Neeraj

    2016-08-01

    In this report, the tuning of the optical bandgap and saturation magnetization of cobalt ferrite (CFO) thin films through low doping of zinc (Zn) has been demonstrated. The Zn doped CFO thin films with doping concentrations (0 to 10%) have been synthesized by ultrasonic assisted chemical vapour deposition technique. The optical bandgap varies from 1.48 to 1.88 eV and saturation magnetization varies from 142 to 221 emu/cc with the increase in the doping concentration and this change in the optical and magnetic properties is attributed to the change in the relative population of the Co2+ at the tetrahedral and octahedral sites. Raman study confirms the decrease in the population of Co2+ at tetrahedral sites with controlled Zn doping in CFO thin films. A quantitative analysis has been presented to explain the observed variation in the optical bandgap and saturation magnetization.

  20. The future of doping control in athletes. Issues related to blood sampling.

    PubMed

    Birkeland, K I; Hemmersbach, P

    1999-07-01

    When current antidoping programmes were developed, the most frequently used doping agents were xenobiotics, such as stimulants and anabolic steroids, that are readily detectable in urine with the use of gas chromatography and mass spectrometry. As control of traditional doping agents became effective, some athletes turned to other means to improve performance, including blood doping and the application of recombinant peptide hormones such as erythropoietin and growth hormone. Doping with these agents is not easily detected in urine samples, and therefore new strategies must be developed as a supplement to those already in use. Such strategies will probably include analysing blood samples, as several of the most promising methods that are able to detect modern doping agents use blood as the analytical matrix. Non-autologous blood doping results in an admixture of self and foreign red blood cells that can be detected in a blood sample with the methods available. Methods to indicate doping with erythropoietin include the indirect finding of an elevated level of soluble transferrin receptor in serum, or a direct demonstration of a shift from the normal to an abnormal spectrum of erythropoietin isoforms. To indicate doping with growth hormone, a set of serum parameters including insulin growth factors and their binding proteins are under investigation as indirect evidence. A direct method using isotopic differences between endogenous and recombinant growth hormones is being investigated. A similar method has been established to detect the administration of testosterone esters. Several legal and ethical questions must be solved before blood sampling can become a part of routine doping control, but the major ethical question is whether sport can continue as today without proper methods to detect many modern doping agents.

  1. 12 CFR 18.1 - Purpose and OMB control number.

    Code of Federal Regulations, 2011 CFR

    2011-01-01

    ... expected to promote better public understanding of, and confidence in, individual national banks and the... public confidence in the national banking system. (b) OMB control number. The collection of...

  2. Mass spectrometric characterization of a prolyl hydroxylase inhibitor GSK1278863, its bishydroxylated metabolite, and its implementation into routine doping controls.

    PubMed

    Thevis, Mario; Milosovich, Susan; Licea-Perez, Hermes; Knecht, Dana; Cavalier, Tom; Schänzer, Wilhelm

    2016-08-01

    Drug candidates, which have the potential of enhancing athletic performance represent a risk of being misused in elite sport. Therefore, there is a need for early consideration by anti-doping authorities and implementation into sports drug testing programmes. The hypoxia-inducible factor (HIF) or prolyl hydroxylase inhibitor (PHI) GSK1278863 represents an advanced candidate of an emerging class of therapeutics that possess substantial potential for abuse in sport due to their capability to stimulate the biogenesis of erythrocytes and, consequently, the individual's oxygen transport capacity. A thorough characterization of such analytes by technologies predominantly used for doping control purposes and the subsequent implementation of the active drug and/or its main urinary metabolite(s) are vital for comprehensive, preventive, and efficient anti-doping work. In the present study, the HIF PHI drug candidate GSK1278863 (comprising a 6-hydroxypyrimidine-2,4-dione nucleus) and its bishydroxylated metabolite M2 (GSK2391220A) were studied regarding their mass spectrometric behaviour under electrospray ionization (ESI-MS/MS) conditions. Synthesized reference materials were used to elucidate dissociation pathways by means of quadrupole/time-of-flight high resolution/high accuracy tandem mass spectrometry, and their detection from spiked urine and elimination study urine samples under routine doping control conditions was established using liquid chromatography-electrospray ionization-tandem mass spectrometry with direct injection. Dissociation pathways to diagnostic product ions of GSK1278863 (e.g. m/z 291, 223, and 122) were proposed as substantiated by determined elemental compositions and MS(n) experiments as well as comparison to spectra of the bishydroxylated analogue M2. An analytical assay based on direct urine injection using liquid chromatography coupled with tandem mass spectrometry (LC-MS/MS) was developed for the simultaneous determination of GSK1278863 in

  3. Using a cognitive architecture for general purpose service robot control

    NASA Astrophysics Data System (ADS)

    Puigbo, Jordi-Ysard; Pumarola, Albert; Angulo, Cecilio; Tellez, Ricardo

    2015-04-01

    A humanoid service robot equipped with a set of simple action skills including navigating, grasping, recognising objects or people, among others, is considered in this paper. By using those skills the robot should complete a voice command expressed in natural language encoding a complex task (defined as the concatenation of a number of those basic skills). As a main feature, no traditional planner has been used to decide skills to be activated, as well as in which sequence. Instead, the SOAR cognitive architecture acts as the reasoner by selecting which action the robot should complete, addressing it towards the goal. Our proposal allows to include new goals for the robot just by adding new skills (without the need to encode new plans). The proposed architecture has been tested on a human-sized humanoid robot, REEM, acting as a general purpose service robot.

  4. Doping-assisted defect control in compound semiconductors

    DOEpatents

    Specht, Petra; Weber, Eicke R.; Weatherford, Todd Russell

    2006-07-11

    The present invention relates to the production of thin film epilayers of III–V and other compounds with acceptor doping wherein the acceptor thermally stabilizes the epilayer, stabilize the naturally incorporated native defect population and therewith maintain the epilayer's beneficial properties upon annealing among other advantageous effects. In particular, balanced doping in which the acceptor concentration is similar to (but does not exceed) the antisite defects in the as-grown material is shown to be particularly advantageous in providing thermal stability, high resistivity and ultrashort trapping times. In particular, MBE growth of LT-GaAs epilayers with balanced Be doping is described in detail. The growth conditions greatly enhance the materials reproducibility (that is, the yield in processed devices). Such growth techniques can be transferred to other III–V materials if the growth conditions are accurately reproduced. Materials produced herein also demonstrate advantages in reproducibility, reliability and radiation hardening.

  5. Increased Photoconductivity Lifetime in GaAs Nanowires by Controlled n-Type and p-Type Doping.

    PubMed

    Boland, Jessica L; Casadei, Alberto; Tütüncüoglu, Gözde; Matteini, Federico; Davies, Christopher L; Jabeen, Fauzia; Joyce, Hannah J; Herz, Laura M; Fontcuberta I Morral, Anna; Johnston, Michael B

    2016-04-26

    Controlled doping of GaAs nanowires is crucial for the development of nanowire-based electronic and optoelectronic devices. Here, we present a noncontact method based on time-resolved terahertz photoconductivity for assessing n- and p-type doping efficiency in nanowires. Using this technique, we measure extrinsic electron and hole concentrations in excess of 10(18) cm(-3) for GaAs nanowires with n-type and p-type doped shells. Furthermore, we show that controlled doping can significantly increase the photoconductivity lifetime of GaAs nanowires by over an order of magnitude: from 0.13 ns in undoped nanowires to 3.8 and 2.5 ns in n-doped and p-doped nanowires, respectively. Thus, controlled doping can be used to reduce the effects of parasitic surface recombination in optoelectronic nanowire devices, which is promising for nanowire devices, such as solar cells and nanowire lasers.

  6. A General Purpose Experiment Controller for low cost Space Application

    NASA Astrophysics Data System (ADS)

    Guzman-Garcia, D.; Rowland, D. E.; Uribe, P.; Nieves-Chinchilla, T.

    2012-12-01

    Space activities are very expensive and include a high degree of risk. Nowadays, CubeSat missions represent a fast and inexpensive way to conduct scientific space research. These platforms are less expensive to develop and build than conventional satellites. There are ample demonstration that these platforms are well suited for a wide range of science missions in different fields, such as astrobiology, astronomy, atmospheric science, space weather and biology. This paper presents a hybrid "processor in an Field Programmable Gate Array (FPGA)" experiment/spacecraft controller for Cubesat missions. The system has two objectives, first is to obtain a multipurpose and easily customizable system aimed at processing the data from the widest kind of instruments and second, to provide the system with the highest processing capabilities in order to be able to perform complex onboard algorithms. Due to the versatility of the system and its reduced dimensions, it can be employed in different space platforms. The system is envisioned to be employed for the first time as the smart radio receiver for the upcoming NASA FireStation instrument. It is one of four experiments manifested to fly on an experiment pallet the U.S Department of Defense plans to deploy on the International Space Station in 2013. FireStation will continue analyzing the link between the Lightning and the Terrestrial Gamma Rays initiated by the FireFly Cubesat. The system is responsible for the management of a set of small Heliophysics instrumentats, including a photometer, magnetometer, and electric and magnetic field antennas. A description of the system architecture and its main features are presented. The main functional and performance tests during the integration and calibration phase of the instruments are also discussed.

  7. Control of Rewriteable Doping Patterns in Graphene/Boron Nitride Heterostructures

    NASA Astrophysics Data System (ADS)

    Kahn, Salman; Velasco, Jairo, Jr.; Wong, Dillon; Lee, Juwon; Tsai, Hsin Zon; Ju, Long; Jiang, Lili; Shi, Zhiwen; Ashby, Paul; Taniguchi, Takashi; Watanabe, Kenji; Zettl, Alex; Wang, Feng; Crommie, Michael

    Spatial control of charge doping in 2D materials is a prerequisite for designing future electronic devices and understanding novel physics. Electrostatic gating and chemical doping are two of the most common methods to achieve this. However, these approaches suffer from complicated fabrication processes that introduce impurities, change material properties irreversibly, and lack flexibility. Here we introduce a new method for patterning rewriteable doping profiles using an STM tip by way of local tip-voltage-induced ionization of defects in a BN substrate. We characterize these spatial doping patterns through local probe and transport techniques. This technique enables many novel device designs for 2D materials, including atomically thin p-n junctions and rewriteable memory devices.

  8. Method for continuous control of composition and doping of pulsed laser deposited films by pressure control

    DOEpatents

    Lowndes, Douglas H.; McCamy, James W.

    1996-01-01

    A method for growing a deposit upon a substrate of semiconductor material involves the utilization of pulsed laser deposition techniques within a low-pressure gas environment. The substrate and a target of a first material are positioned within a deposition chamber and a low-pressure gas atmosphere is developed within the chamber. The substrate is then heated, and the target is irradiated, so that atoms of the target material are ablated from the remainder of the target, while atoms of the gas simultaneously are adsorbed on the substrate/film surface. The ablated atoms build up upon the substrate, together with the adsorbed gas atoms to form the thin-film deposit on the substrate. By controlling the pressure of the gas of the chamber atmosphere, the composition of the formed deposit can be controlled, and films of continuously variable composition or doping can be grown from a single target of fixed composition.

  9. Multi Purpose Crew Vehicle Active Thermal Control and Environmental Control and Life Support Development Status

    NASA Technical Reports Server (NTRS)

    Lewis, John F.; Barido, Richard A.; Boehm, Paul; Cross, Cynthia D.; Rains, George Edward

    2014-01-01

    The Orion Multi Purpose Crew Vehicle (MPCV) is the first crew transport vehicle to be developed by the National Aeronautics and Space Administration (NASA) in the last thirty years. Orion is currently being developed to transport the crew safely beyond Earth orbit. This year, the vehicle focused on building the Exploration Flight Test 1 (EFT1) vehicle to be launched in September of 2014. The development of the Orion Active Thermal Control (ATCS) and Environmental Control and Life Support (ECLS) System, focused on the integrating the components into the EFT1 vehicle and preparing them for launch. Work also has started on preliminary design reviews for the manned vehicle. Additional development work is underway to keep the remaining component progressing towards implementation on the flight tests of EM1 in 2017 and of EM2 in 2020. This paper covers the Orion ECLS development from April 2013 to April 2014

  10. 27 CFR 27.75 - Samples of distilled spirits, wine, and beer for quality control purposes.

    Code of Federal Regulations, 2011 CFR

    2011-04-01

    ... spirits, wine, and beer for quality control purposes. 27.75 Section 27.75 Alcohol, Tobacco Products and... DISTILLED SPIRITS, WINES, AND BEER General Requirements Exemptions § 27.75 Samples of distilled spirits, wine, and beer for quality control purposes. Samples of distilled spirits, wine, and beer in...

  11. 27 CFR 27.75 - Samples of distilled spirits, wine, and beer for quality control purposes.

    Code of Federal Regulations, 2013 CFR

    2013-04-01

    ... spirits, wine, and beer for quality control purposes. 27.75 Section 27.75 Alcohol, Tobacco Products and... DISTILLED SPIRITS, WINES, AND BEER General Requirements Exemptions § 27.75 Samples of distilled spirits, wine, and beer for quality control purposes. Samples of distilled spirits, wine, and beer in...

  12. 27 CFR 27.75 - Samples of distilled spirits, wine, and beer for quality control purposes.

    Code of Federal Regulations, 2012 CFR

    2012-04-01

    ... spirits, wine, and beer for quality control purposes. 27.75 Section 27.75 Alcohol, Tobacco Products and... DISTILLED SPIRITS, WINES, AND BEER General Requirements Exemptions § 27.75 Samples of distilled spirits, wine, and beer for quality control purposes. Samples of distilled spirits, wine, and beer in...

  13. 27 CFR 27.75 - Samples of distilled spirits, wine, and beer for quality control purposes.

    Code of Federal Regulations, 2014 CFR

    2014-04-01

    ... spirits, wine, and beer for quality control purposes. 27.75 Section 27.75 Alcohol, Tobacco Products and... DISTILLED SPIRITS, WINES, AND BEER General Requirements Exemptions § 27.75 Samples of distilled spirits, wine, and beer for quality control purposes. Samples of distilled spirits, wine, and beer in...

  14. 27 CFR 27.75 - Samples of distilled spirits, wine, and beer for quality control purposes.

    Code of Federal Regulations, 2010 CFR

    2010-04-01

    ... spirits, wine, and beer for quality control purposes. 27.75 Section 27.75 Alcohol, Tobacco Products and... DISTILLED SPIRITS, WINES, AND BEER General Requirements Exemptions § 27.75 Samples of distilled spirits, wine, and beer for quality control purposes. Samples of distilled spirits, wine, and beer in...

  15. N-type control of single-crystal diamond films by ultra-lightly phosphorus doping

    NASA Astrophysics Data System (ADS)

    Kato, Hiromitsu; Ogura, Masahiko; Makino, Toshiharu; Takeuchi, Daisuke; Yamasaki, Satoshi

    2016-10-01

    A wide impurity doping range of p- and n-type diamond semiconductors will facilitate the development of various electronics. This study focused on producing n-type diamond with ultra-lightly impurity doping concentrations. N-type single-crystal diamond films were grown on (111)-oriented diamond substrates by phosphorus doping using the optimized doping conditions based on microwave plasma-enhanced chemical vapor deposition with a high magnetron output power of 3600 W. The surface morphology was investigated by an optical microscopy using the Nomarski prism and confocal laser microscopy, and the phosphorus concentration was estimated by a secondary ion mass spectrometry. The phosphorus concentration was reproducibly controlled to between 2 × 1015 and 3 × 1017 cm-3 using a standard mass flow controller, and the average incorporation efficiency was around 0.1%. The electrical properties of the films were characterized by the Hall effect measurements as a function of temperature over a wide range from 220 to 900 K. N-type conductivity with thermal activation from a phosphorus donor level at around 0.57 eV was clearly observed for all the phosphorus-doped diamond films. The electron mobility of the film with a phosphorus concentration of 2 × 1015 cm-3 was recorded at 1060 cm2/V s at 300 K and 1500 cm2/V s at 225 K.

  16. Controlling the Bandgap of Boron Nitride Nanotubes with Carbon Doping

    NASA Astrophysics Data System (ADS)

    Mousavi, Hamze; Bagheri, Mehran

    2015-08-01

    This study explores the effects of doping by carbon (C) atoms on electronic properties of (10,10) and (16,0) boron nitride (BN) nanotubes (NTs). We exploit the random tight-binding model with Green's function technique and coherent potential approximation to show that the C dopant causes a decrease in the bandgap of the BN NTs, and their matching Van Hove singularities (VHS) in the density of states (DOS) are broadened. When the impurity concentration is large enough, the form of the DOS of the BN NTs becomes similar to that of metallic (10,10) and semiconducting (16,0) C NTs and their VHS get sharpened. This work might provide opportunities for creating new optoelectronic devices based on BN honeycomb nanosystems.

  17. Controlling the volumetric parameters of nitrogen-doped carbon nanotube cups.

    PubMed

    Allen, Brett L; Keddie, Matthew B; Star, Alexander

    2010-07-01

    Analogous to multiwalled carbon nanotubes, nitrogen-doped carbon nanotube cups (NCNCs) have been synthesized with defined volumetric parameters (diameter and segment lengths) by controlling the catalyst particle size and the concentration of nitrogen precursor utilized in the chemical vapor deposition (CVD) reaction, allowing for tailored interior cavity space of cross-linked NCNCs, i.e. nanocapsules.

  18. Control of the residual doping of InAs/(GaIn)Sb infrared superlattices

    NASA Astrophysics Data System (ADS)

    Bürkle, L.; Fuchs, F.; Schmitz, J.; Pletschen, W.

    2000-09-01

    Magnetotransport and photoluminescence (PL) measurements on InAs/(GaIn)Sb superlattices (SLs) grown by molecular-beam epitaxy on GaSb substrates at different substrate temperatures are reported. With increasing growth temperature, a transition of the SLs from residual n type to residual p-type doping was observed. For n-type samples, a decrease in the electron concentration leads to a strong increase in the PL intensity. In contrast, the PL intensity of p-type samples is only weakly dependent on the hole concentration. This correlation can be used to control the residual doping of the SLs.

  19. Tunable electronic properties of graphene through controlling bonding configurations of doped nitrogen atoms

    NASA Astrophysics Data System (ADS)

    Zhang, Jia; Zhao, Chao; Liu, Na; Zhang, Huanxi; Liu, Jingjing; Fu, Yong Qing; Guo, Bin; Wang, Zhenlong; Lei, Shengbin; Hu, Pingan

    2016-06-01

    Single–layer and mono–component doped graphene is a crucial platform for a better understanding of the relationship between its intrinsic electronic properties and atomic bonding configurations. Large–scale doped graphene films dominated with graphitic nitrogen (GG) or pyrrolic nitrogen (PG) were synthesized on Cu foils via a free radical reaction at growth temperatures of 230–300 °C and 400–600 °C, respectively. The bonding configurations of N atoms in the graphene lattices were controlled through reaction temperature, and characterized using Raman spectroscopy, X–ray photoelectron spectroscopy and scanning tunneling microscope. The GG exhibited a strong n–type doping behavior, whereas the PG showed a weak n–type doping behavior. Electron mobilities of the GG and PG were in the range of 80.1–340 cm2 V‑1·s‑1 and 59.3–160.6 cm2 V‑1·s‑1, respectively. The enhanced doping effect caused by graphitic nitrogen in the GG produced an asymmetry electron–hole transport characteristic, indicating that the long–range scattering (ionized impurities) plays an important role in determining the carrier transport behavior. Analysis of temperature dependent conductance showed that the carrier transport mechanism in the GG was thermal excitation, whereas that in the PG, was a combination of thermal excitation and variable range hopping.

  20. Tunable electronic properties of graphene through controlling bonding configurations of doped nitrogen atoms

    PubMed Central

    Zhang, Jia; Zhao, Chao; Liu, Na; Zhang, Huanxi; Liu, Jingjing; Fu, Yong Qing; Guo, Bin; Wang, Zhenlong; Lei, Shengbin; Hu, PingAn

    2016-01-01

    Single–layer and mono–component doped graphene is a crucial platform for a better understanding of the relationship between its intrinsic electronic properties and atomic bonding configurations. Large–scale doped graphene films dominated with graphitic nitrogen (GG) or pyrrolic nitrogen (PG) were synthesized on Cu foils via a free radical reaction at growth temperatures of 230–300 °C and 400–600 °C, respectively. The bonding configurations of N atoms in the graphene lattices were controlled through reaction temperature, and characterized using Raman spectroscopy, X–ray photoelectron spectroscopy and scanning tunneling microscope. The GG exhibited a strong n–type doping behavior, whereas the PG showed a weak n–type doping behavior. Electron mobilities of the GG and PG were in the range of 80.1–340 cm2 V−1·s−1 and 59.3–160.6 cm2 V−1·s−1, respectively. The enhanced doping effect caused by graphitic nitrogen in the GG produced an asymmetry electron–hole transport characteristic, indicating that the long–range scattering (ionized impurities) plays an important role in determining the carrier transport behavior. Analysis of temperature dependent conductance showed that the carrier transport mechanism in the GG was thermal excitation, whereas that in the PG, was a combination of thermal excitation and variable range hopping. PMID:27325386

  1. Doping strategies to control A-centres in silicon: insights from hybrid density functional theory.

    PubMed

    Wang, H; Chroneos, A; Londos, C A; Sgourou, E N; Schwingenschlögl, U

    2014-05-14

    Hybrid density functional theory is used to gain insights into the interaction of intrinsic vacancies (V) and oxygen-vacancy pairs (VO, known as A-centres) with the dopants (D) germanium (Ge), tin (Sn), and lead (Pb) in silicon (Si). We determine the structures as well as binding and formation energies of the DVO and DV complexes. The results are discussed in terms of the density of states and in view of the potential of isovalent doping to control A-centres in Si. We argue that doping with Sn is the most efficient isovalent doping strategy to suppress A-centres by the formation of SnVO complexes, as these are charge neutral and strongly bound.

  2. Basic analytical methods for identification of erythropoiesis-stimulating agents in doping control

    NASA Astrophysics Data System (ADS)

    Postnikov, P. V.; Krotov, G. I.; Efimova, Yu A.; Rodchenkov, G. M.

    2016-02-01

    The design of new erythropoiesis-stimulating agents for clinical use necessitates constant development of methods for detecting the abuse of these substances, which are prohibited under the World Anti-Doping Code and are included in the World Anti-Doping Agency (WADA) prohibited list. This review integrates and describes systematically the published data on the key methods currently used by WADA-accredited anti-doping laboratories around the world to detect the abuse of erythropoiesis-stimulating agents, including direct methods (various polyacrylamide gel electrophoresis techniques, enzyme-linked immunosorbent assay, membrane enzyme immunoassay and mass spectrometry) and indirect methods (athlete biological passport). Particular attention is given to promising approaches and investigations that can be used to control prohibited erythropoietins in the near future. The bibliography includes 122 references.

  3. All optical mode controllable Er-doped random fiber laser with distributed Bragg gratings.

    PubMed

    Zhang, W L; Ma, R; Tang, C H; Rao, Y J; Zeng, X P; Yang, Z J; Wang, Z N; Gong, Y; Wang, Y S

    2015-07-01

    An all-optical method to control the lasing modes of Er-doped random fiber lasers (RFLs) is proposed and demonstrated. In the RFL, an Er-doped fiber (EDF) recoded with randomly separated fiber Bragg gratings (FBG) is used as the gain medium and randomly distributed reflectors, as well as the controllable element. By combining random feedback of the FBG array and Fresnel feedback of a cleaved fiber end, multi-mode coherent random lasing is obtained with a threshold of 14 mW and power efficiency of 14.4%. Moreover, a laterally-injected control light is used to induce local gain perturbation, providing additional gain for certain random resonance modes. As a result, active mode selection of the RFL is realized by changing locations of the laser cavity that is exposed to the control light. PMID:26125397

  4. Atomically controlled substitutional boron-doping of graphene nanoribbons

    PubMed Central

    Kawai, Shigeki; Saito, Shohei; Osumi, Shinichiro; Yamaguchi, Shigehiro; Foster, Adam S.; Spijker, Peter; Meyer, Ernst

    2015-01-01

    Boron is a unique element in terms of electron deficiency and Lewis acidity. Incorporation of boron atoms into an aromatic carbon framework offers a wide variety of functionality. However, the intrinsic instability of organoboron compounds against moisture and oxygen has delayed the development. Here, we present boron-doped graphene nanoribbons (B-GNRs) of widths of N=7, 14 and 21 by on-surface chemical reactions with an employed organoboron precursor. The location of the boron dopant is well defined in the centre of the B-GNR, corresponding to 4.8 atom%, as programmed. The chemical reactivity of B-GNRs is probed by the adsorption of nitric oxide (NO), which is most effectively trapped by the boron sites, demonstrating the Lewis acid character. Structural properties and the chemical nature of the NO-reacted B-GNR are determined by a combination of scanning tunnelling microscopy, high-resolution atomic force microscopy with a CO tip, and density functional and classical computations. PMID:26302943

  5. Possibility of analytical finding of glycerol caused by self-catheterization in doping control.

    PubMed

    Okano, Masato; Nishitani, Yasunori; Kageyama, Shinji

    2014-01-01

    Glycerol is listed on the World Anti-Doping Agency (WADA) prohibited list as a masking agent principally because the administration of glycerol increases plasma volume and decreases the concentration of haemoglobin and the value of haematocrit in blood. Glycerol is a naturally occurring substance; therefore, the threshold is set as 1.0 mg/mL in the WADA technical document (WADA TD2013DL). In a WADA-accredited doping control laboratory, three doping control urine specimens collected from impaired athletes were determined to contain a high concentration of glycerol (>1.0 mg/mL); two of these specimens were considered adverse analytical findings (AAFs). Self-catheterization is necessary for athletes with neurological disorders such as neurogenic bladder dysfunction. We conducted a simple simulation of self-catheterization as an experimental test using urethral catheters with an antiseptic agent containing glycerol to confirm the influence of this antiseptic agent on the quantitative value of glycerol in doping control analysis. Some users employ a catheter with glycerol solution (ca. 1 mL) to avoid pain during use. The urine sample passed through such a catheter exhibited a glycerol concentration (4.94 mg/mL) greater than the threshold level. In September 2014, the threshold for glycerol will change from 1.0 to 4.3 mg/mL (WADA TD2014DL); however, a possibility exists for the quantitative value of glycerol in doping control analysis to exceed the threshold because of the use of an antiseptic agent containing glycerol for self-catheterization. The AAF for glycerol for impaired athletes, particularly those who participate in Paralympic sports, should account for the use of a catheter with glycerol.

  6. Encapsulation of biomolecules for bioanalytical purposes: preparation of diclofenac antibody-doped nanometer-sized silica particles by reverse micelle and sol-gel processing.

    PubMed

    Tsagkogeorgas, Fotios; Ochsenkühn-Petropoulou, Maria; Niessner, Reinhard; Knopp, Dietmar

    2006-07-28

    In recent years, the sol-gel technique has attracted increasing interest as a unique approach to immobilize biomolecules for bioanalytical applications as well as biochemical and biophysical studies. For this purpose, crushed biomolecule-doped sol-gel glass monoliths have been widely used. In the present work, for the first time, the encapsulation of anti-diclofenac antibodies in silica nanoparticles was carried out by a combination of reverse micelle and sol-gel technique. Cyclohexane was used for the preparation of the microemulsion as organic solvent, while surfactant Igepal CO-520 was found to be the optimal stabilizer. The antibody source was a purified IgG fraction originating from a polyclonal rabbit antiserum. Tetramethyl orthosilicate (TMOS) was used as precursor. Rather uniform, monodispersed and spherical silica particles of about 70nm diameter size were fabricated, as was demonstrated by transmission electron microscopy (TEM) and scanning electron microscopy/energy dispersive X-ray fluorescence analysis (SEM/EDX). The biological activity of the encapsulated antibodies was evaluated by incubation of the nanoparticles with a diclofenac standard solution and analysis of the filtrate and followed washing solutions by a highly sensitive enzyme-linked immunosorbent assay (ELISA), using non-doped particles as blanks. While only about 6% of the added diclofenac was nonspecifically retained by the blank, the corresponding amount of about 66% was much higher with the antibody-doped particles. An obvious advantage of this approach is the general applicability of the developed technique for a mild immobilization of different antibody species.

  7. Optically and electrically controlled circularly polarized emission from cholesteric liquid crystal materials doped with semiconductor quantum dots.

    PubMed

    Bobrovsky, Alexey; Mochalov, Konstantin; Oleinikov, Vladimir; Sukhanova, Alyona; Prudnikau, Anatol; Artemyev, Mikhail; Shibaev, Valery; Nabiev, Igor

    2012-12-01

    Novel types of electro- and photoactive quantum dot-doped cholesteric materials have been engineered. UV-irradiation or electric field application allows one to control the degree of circular polarization and intensity of fluorescence emission by prepared quantum dot-doped liquid crystal films. PMID:22972420

  8. Compound semi-conductors and controlled doping thereof

    NASA Technical Reports Server (NTRS)

    Larkin, David J. (Inventor); Neudeck, Philip G. (Inventor); Powell, J. Anthony (Inventor); Matus, Lawrence G. (Inventor)

    1998-01-01

    A method of controlling the amount of impurity incorporation in a crystal grown by a chemical vapor deposition process. Conducted in a growth chamber, the method includes the controlling of the concentration of the crystal growing components in the growth chamber to affect the demand of particular growth sites within the growing crystal thereby controlling impurity incorporation into the growth sites.

  9. Controlled n-Type Doping of Carbon Nanotube Transistors by an Organorhodium Dimer.

    PubMed

    Geier, Michael L; Moudgil, Karttikay; Barlow, Stephen; Marder, Seth R; Hersam, Mark C

    2016-07-13

    Single-walled carbon nanotube (SWCNT) transistors are among the most developed nanoelectronic devices for high-performance computing applications. While p-type SWCNT transistors are easily achieved through adventitious adsorption of atmospheric oxygen, n-type SWCNT transistors require extrinsic doping schemes. Existing n-type doping strategies for SWCNT transistors suffer from one or more issues including environmental instability, limited carrier concentration modulation, undesirable threshold voltage control, and/or poor morphology. In particular, commonly employed benzyl viologen n-type doping layers possess large thicknesses, which preclude top-gate transistor designs that underlie high-density integrated circuit layouts. To overcome these limitations, we report here the controlled n-type doping of SWCNT thin-film transistors with a solution-processed pentamethylrhodocene dimer. The charge transport properties of organorhodium-treated SWCNT thin films show consistent n-type behavior when characterized in both Hall effect and thin-film transistor geometries. Due to the molecular-scale thickness of the organorhodium adlayer, large-area arrays of top-gated, n-type SWCNT transistors are fabricated with high yield. This work will thus facilitate ongoing efforts to realize high-density SWCNT integrated circuits. PMID:27253896

  10. Object classification in images for Epo doping control based on fuzzy decision trees

    NASA Astrophysics Data System (ADS)

    Bajla, Ivan; Hollander, Igor; Heiss, Dorothea; Granec, Reinhard; Minichmayr, Markus

    2005-02-01

    Erythropoietin (Epo) is a hormone which can be misused as a doping substance. Its detection involves analysis of images containing specific objects (bands), whose position and intensity are critical for doping positivity. Within a research project of the World Anti-Doping Agency (WADA) we are implementing the GASepo software that should serve for Epo testing in doping control laboratories world-wide. For identification of the bands we have developed a segmentation procedure based on a sequence of filters and edge detectors. Whereas all true bands are properly segmented, the procedure generates a relatively high number of false positives (artefacts). To separate these artefacts we suggested a post-segmentation supervised classification using real-valued geometrical measures of objects. The method is based on the ID3 (Ross Quinlan's) rule generation method, where fuzzy representation is used for linking the linguistic terms to quantitative data. The fuzzy modification of the ID3 method provides a framework that generates fuzzy decision trees, as well as fuzzy sets for input data. Using the MLTTM software (Machine Learning Framework) we have generated a set of fuzzy rules explicitly describing bands and artefacts. The method eliminated most of the artefacts. The contribution includes a comparison of the obtained misclassification errors to the errors produced by some other statistical classification methods.

  11. Controlling the volumetric parameters of nitrogen-doped carbon nanotube cups

    NASA Astrophysics Data System (ADS)

    Allen, Brett L.; Keddie, Matthew B.; Star, Alexander

    2010-07-01

    Analogous to multiwalled carbon nanotubes, nitrogen-doped carbon nanotube cups (NCNCs) have been synthesized with defined volumetric parameters (diameter and segment lengths) by controlling the catalyst particle size and the concentration of nitrogen precursor utilized in the chemical vapor deposition (CVD) reaction, allowing for tailored interior cavity space of cross-linked NCNCs, i.e. nanocapsules.Analogous to multiwalled carbon nanotubes, nitrogen-doped carbon nanotube cups (NCNCs) have been synthesized with defined volumetric parameters (diameter and segment lengths) by controlling the catalyst particle size and the concentration of nitrogen precursor utilized in the chemical vapor deposition (CVD) reaction, allowing for tailored interior cavity space of cross-linked NCNCs, i.e. nanocapsules. Electronic supplementary information (ESI) available: AFM and DLS of FeNPs, high-resolution TEM and EELS analysis, and TEM of statistical distributions. See DOI: 10.1039/c0nr00043d

  12. Interfacial control of oxygen vacancy doping and electrical conduction in thin film oxide heterostructures

    PubMed Central

    Veal, Boyd W.; Kim, Seong Keun; Zapol, Peter; Iddir, Hakim; Baldo, Peter M.; Eastman, Jeffrey A.

    2016-01-01

    Oxygen vacancies in proximity to surfaces and heterointerfaces in oxide thin film heterostructures have major effects on properties, resulting, for example, in emergent conduction behaviour, large changes in metal-insulator transition temperatures or enhanced catalytic activity. Here we report the discovery of a means of reversibly controlling the oxygen vacancy concentration and distribution in oxide heterostructures consisting of electronically conducting In2O3 films grown on ionically conducting Y2O3-stabilized ZrO2 substrates. Oxygen ion redistribution across the heterointerface is induced using an applied electric field oriented in the plane of the interface, resulting in controlled oxygen vacancy (and hence electron) doping of the film and possible orders-of-magnitude enhancement of the film's electrical conduction. The reversible modified behaviour is dependent on interface properties and is attained without cation doping or changes in the gas environment. PMID:27283250

  13. Clean Photothermal Heating and Controlled Release From Near Infrared Dye Doped Nanoparticles Without Oxygen Photosensitization

    PubMed Central

    Guha, Samit; Shaw, Scott K.; Spence, Graeme T.; Roland, Felicia M.; Smith, Bradley D.

    2015-01-01

    The photothermal heating and release properties of biocompatible organic nanoparticles, doped with a near-infrared croconaine (Croc) dye, were compared with analogous nanoparticles doped with the common near-infrared dyes ICG and IR780. Separate formulations of lipid-polymer-hybrid nanoparticles and liposomes, each containing Croc dye, absorbed strongly at 808 nm and generated clean laser-induced heating (no production of 1O2 and no photobleaching of the dye). In contrast, laser-induced heating of nanoparticles containing ICG or IR780 produced reactive 1O2 leading to bleaching of the dye and also decomposition of co-encapsulated payload such as the drug Doxorubicin. Croc dye was especially useful as a photothermal agent for laser controlled release of chemically sensitive payload from nanoparticles. Solution state experiments demonstrated repetitive fractional release of water soluble fluorescent dye from the interior of thermosensitive liposomes. Additional experiments used a focused laser beam to control leakage from immobilized liposomes with very high spatial and temporal precision. The results indicate that fractional photothermal leakage from nanoparticles doped with Croc dye is a promising method for a range of controlled release applications. PMID:26149326

  14. The ethics of blood testing as an element of doping control in sport.

    PubMed

    Browne, A; Lachance, V; Pipe, A

    1999-04-01

    Sport authorities continue to confront a variety of perplexing issues as they attempt to address effectively and efficiently the problems posed by doping. The emergence of the phenomena of blood doping and the administration of erythropoietin have added to the challenges faced by doping control authorities. Some sport organizations have introduced blood tests in an attempt to deal with these issues despite the absence of any effective test for the detection of the administration of homologous blood products or eythropoietin. A number of ethical issues are raised by such developments. Even in the presence of an effective test it is suggested that the decision to implement a specific testing approach can be reached by considering the wishes of a hypothetical "Fair Competitor" and an analysis of the costs involved. In this respect the Fair Competitor assumes in the sport community the role that the "reasonable person" occupies in law, permitting an analysis of a proposed course of action. In making any decision regarding the implementation of any test, a Fair Competitor would be guided by considerations of the postulated advantage and incidence of a doping technique, the likelihood of false positive and negative results, the risk of unwanted consequences of a testing process, and a concern that a specific test not accelerate the likelihood of the use of other doping methods. This approach is applied to a consideration of the appropriateness of blood testing in sport. It is concluded, using such an analysis, that in their present state of development, blood tests should not be implemented. It is recognized that certain sport authorities currently use blood tests to exclude competitors whose blood values exceed certain predetermined levels on the grounds of concerns regarding health and safety. Screening of this kind is beyond the purview of this discussion.

  15. Controlling Octahedral Rotations in a Perovskite via Strain Doping

    PubMed Central

    Herklotz, A.; Wong, A. T.; Meyer, T.; Biegalski, M. D.; Lee, H. N.; Ward, T. Z.

    2016-01-01

    The perovskite unit cell is the fundamental building block of many functional materials. The manipulation of this crystal structure is known to be of central importance to controlling many technologically promising phenomena related to superconductivity, multiferroicity, mangetoresistivity, and photovoltaics. The broad range of properties that this structure can exhibit is in part due to the centrally coordinated octahedra bond flexibility, which allows for a multitude of distortions from the ideal highly symmetric structure. However, continuous and fine manipulation of these distortions has never been possible. Here, we show that controlled insertion of He atoms into an epitaxial perovskite film can be used to finely tune the lattice symmetry by modifying the local distortions, i.e., octahedral bonding angle and length. Orthorhombic SrRuO3 films coherently grown on SrTiO3 substrates are used as a model system. Implanted He atoms are confirmed to induce out-of-plane strain, which provides the ability to controllably shift the bulk-like orthorhombically distorted phase to a tetragonal structure by shifting the oxygen octahedra rotation pattern. These results demonstrate that He implantation offers an entirely new pathway to strain engineering of perovskite-based complex oxide thin films, useful for creating new functionalities or properties in perovskite materials. PMID:27215804

  16. Controlling octahedral rotations in a perovskite via strain doping

    DOE PAGES

    Herklotz, Andreas; Biegalski, Michael D.; Lee, Ho Nyung; Ward, Thomas Zac; Wong, A. T.; Meyer, T.

    2016-05-24

    The perovskite unit cell is the fundamental building block of many functional materials. The manipulation of this crystal structure is known to be of central importance to controlling many technologically promising phenomena related to superconductivity, multiferroicity, mangetoresistivity, and photovoltaics. The broad range of properties that this structure can exhibit is in part due to the centrally coordinated octahedra bond flexibility, which allows for a multitude of distortions from the ideal highly symmetric structure. However, continuous and fine manipulation of these distortions has never been possible. Here, we show that controlled insertion of He atoms into an epitaxial perovskite film canmore » be used to finely tune the lattice symmetry by modifying the local distortions, i.e., octahedral bonding angle and length. Orthorhombic SrRuO3 films coherently grown on SrTiO3 substrates are used as a model system. Implanted He atoms are confirmed to induce out-of-plane strain, which provides the ability to controllably shift the bulk-like orthorhombically distorted phase to a tetragonal structure by shifting the oxygen octahedra rotation pattern. Lastly, these results demonstrate that He implantation offers an entirely new pathway to strain engineering of perovskite-based complex oxide thin films, useful for creating new functionalities or properties in perovskite materials.« less

  17. Controlling Octahedral Rotations in a Perovskite via Strain Doping

    NASA Astrophysics Data System (ADS)

    Herklotz, A.; Wong, A. T.; Meyer, T.; Biegalski, M. D.; Lee, H. N.; Ward, T. Z.

    2016-05-01

    The perovskite unit cell is the fundamental building block of many functional materials. The manipulation of this crystal structure is known to be of central importance to controlling many technologically promising phenomena related to superconductivity, multiferroicity, mangetoresistivity, and photovoltaics. The broad range of properties that this structure can exhibit is in part due to the centrally coordinated octahedra bond flexibility, which allows for a multitude of distortions from the ideal highly symmetric structure. However, continuous and fine manipulation of these distortions has never been possible. Here, we show that controlled insertion of He atoms into an epitaxial perovskite film can be used to finely tune the lattice symmetry by modifying the local distortions, i.e., octahedral bonding angle and length. Orthorhombic SrRuO3 films coherently grown on SrTiO3 substrates are used as a model system. Implanted He atoms are confirmed to induce out-of-plane strain, which provides the ability to controllably shift the bulk-like orthorhombically distorted phase to a tetragonal structure by shifting the oxygen octahedra rotation pattern. These results demonstrate that He implantation offers an entirely new pathway to strain engineering of perovskite-based complex oxide thin films, useful for creating new functionalities or properties in perovskite materials.

  18. Controlled in situ boron doping of diamond thin films using solution phase

    NASA Astrophysics Data System (ADS)

    Roy, M.; Dua, A. K.; Nuwad, J.; Girija, K. G.; Tyagi, A. K.; Kulshreshtha, S. K.

    2006-12-01

    Controlled boron doping of diamond film using nontoxic reagents is a challenge in itself. During the present study, attempts have been made to dope diamond films in situ with boron from a solution of boric acid (H3BO3) in methanol (CH3OH) using a specially designed bubbler that ensured continuous and controlled flow of vapors of boron precursors during deposition. The samples are thoroughly characterized using a host of techniques comprising of x-ray photoelectron spectroscopy, Raman, x-ray diffraction, and current-voltage measurements (I-V). Cross-sectional micro-Raman spectroscopy has been used to obtain depth profile of boron in diamond films. Boron concentration ([B]) in the films is found to vary linearly on a semilog scale with molarity (M) of H3BO3 in CH3OH. Lattice constant of our samples is smaller than the reported American society for testing and materials (ASTM) values due to oxygen incorporation and it increases with [B] in the diamond samples. Heavily boron doped samples exhibit Fano deformation of the Raman line shape and negative and/zero activation barrier in temperature dependent I-V measurements that indicate the formation of metallic phase in the samples. The present study illustrates the feasibility of safe and controlled boron doping of diamond films using a solution of H3BO3 in CH3OH over a significant range of [B] from semiconductor to metallic regime but with a little adverse effect due to unintentional but unavoidable incorporation of oxygen.

  19. Doping control analysis of trimetazidine and characterization of major metabolites using mass spectrometric approaches.

    PubMed

    Sigmund, Gerd; Koch, Anja; Orlovius, Anne-Katrin; Guddat, Sven; Thomas, Andreas; Schänzer, Wilhelm; Thevis, Mario

    2014-01-01

    Since January 2014, the anti-anginal drug trimetazidine [1-(2,3,4-trimethoxybenzyl)-piperazine] has been classified as prohibited substance by the World Anti-Doping Agency (WADA), necessitating specific and robust detection methods in sports drug testing laboratories. In the present study, the implementation of the intact therapeutic agent into two different initial testing procedures based on gas chromatography-mass spectrometry (GC-MS) and liquid chromatography-tandem mass spectrometry (LC-MS/MS) is reported, along with the characterization of urinary metabolites by electrospray ionization-high resolution/high accuracy (tandem) mass spectrometry. For GC-MS analyses, urine samples were subjected to liquid-liquid extraction sample preparation, while LC-MS/MS analyses were conducted by established 'dilute-and-inject' approaches. Both screening methods were validated for trimetazidine concerning specificity, limits of detection (0.5-50 ng/mL), intra-day and inter-day imprecision (<20%), and recovery (41%) in case of the GC-MS-based method. In addition, major metabolites such as the desmethylated trimetazidine and the corresponding sulfoconjugate, oxo-trimetazidine, and trimetazidine-N-oxide as identified in doping control samples were used to complement the LC-MS/MS-based assay, although intact trimetazidine was found at highest abundance of the relevant trimetazidine-related analytes in all tested sports drug testing samples. Retrospective data mining regarding doping control analyses conducted between 1999 and 2013 at the Cologne Doping Control Laboratory concerning trimetazidine revealed a considerable prevalence of the drug particularly in endurance and strength sports accounting for up to 39 findings per year.

  20. Controlled synthesis of Eu2+ and Eu3+ doped ZnS quantum dots and their photovoltaic and magnetic properties

    NASA Astrophysics Data System (ADS)

    Horoz, Sabit; Yakami, Baichhabi; Poudyal, Uma; Pikal, Jon M.; Wang, Wenyong; Tang, Jinke

    2016-04-01

    Eu-doped ZnS quantum dots (QDs) have been synthesized by wet-chemical method and found to form in zinc blende (cubic) structure. Both Eu2+ and Eu3+ doped ZnS can be controllably synthesized. The Eu2+ doped ZnS QDs show broad photoluminescence emission peak around 512 nm, which is from the Eu2+ intra-ion transition of 4f6d1 - 4f7, while the Eu3+ doped samples exhibit narrow emission lines characteristic of transitions between the 4f levels. The investigation of the magnetic properties shows that the Eu3+ doped samples exhibit signs of ferromagnetism, on the other hand, Eu2+ doped samples are paramagnetic of Curie-Weiss type. The incident photon to electron conversion efficiency is increased with the Eu doping, which suggests the QD solar cell efficiency can be enhanced by Eu doping due to widened absorption windows. This is an attractive approach to utilize benign and environmentally friendly wide band gap ZnS QDs in solar cell technology.

  1. Electric-field control of spin-orbit torque in magnetically doped topological insulators

    NASA Astrophysics Data System (ADS)

    Fan, Yabin; Shao, Qiming; Kou, Xufeng; Upadhyaya, Pramey; Wang, Kang

    Recent advances of spin-orbit torques (SOTs) generated by topological insulators (TIs) have drawn increasing interest to the spin-momentum locking feature of TIs' surface states, which can potentially provide a very efficient means to generate SOTs for spintronic applications. In this presentation, we will show the magnetization switching through current-induced giant SOT in both TI/Cr-doped TI bilayer and uniformly Cr-doped TI films In particular, we show that the current-induced SOT has significant contribution from the spin-momentum locked surface states of TIs. We find that the spin torque efficiency is in general three orders of magnitude larger than those reported in heavy metal/ferromagnetic heterostructures. In the second part, we will present the electric-field control of the giant SOT in magnetically doped TIs, which suggests promising gate-controlled spin-torque device applications. The giant SOT and efficient current-induced magnetization switching exhibited by the magnetic TIs may lead to innovative spintronic applications such as ultralow power dissipation memory and logic devices. We acknowledge the supports from DARPA, FAME, SHINES and ARO programs.

  2. Few-mode erbium-doped fiber amplifier with photonic lantern for pump spatial mode control.

    PubMed

    Lopez-Galmiche, G; Sanjabi Eznaveh, Z; Antonio-Lopez, J E; Velazquez Benitez, A M; Rodriguez Asomoza, J; Sanchez Mondragon, J J; Gonnet, C; Sillard, P; Li, G; Schülzgen, A; Okonkwo, C M; Amezcua Correa, R

    2016-06-01

    We demonstrate a few-mode erbium-doped fiber amplifier employing a mode-selective photonic lantern for controlling the modal content of the pump light. Amplification of six spatial modes in a 5 m long erbium-doped fiber to ∼6.2  dBm average power is obtained while maintaining high modal fidelity. Through mode-selective forward pumping of the two degenerate LP21 modes operating at 976 nm, differential modal gains of <1  dB between all modes and signal gains of ∼16  dB at 1550 nm are achieved. In addition, low differential modal gain for near-full C-band operation is demonstrated. PMID:27244421

  3. Controlled ambipolar doping and gate voltage dependent carrier diffusion length in lead sulfide nanowires.

    PubMed

    Yang, Yiming; Li, Jiao; Wu, Hengkui; Oh, Eunsoon; Yu, Dong

    2012-11-14

    We report a simple, controlled doping method for achieving n-type, intrinsic, and p-type lead sulfide (PbS) nanowires (NWs) grown by chemical vapor deposition without introducing any impurities. A wide range of carrier concentrations is realized by adjusting the ratio between the Pb and S precursors. The field effect electron mobility of n-type PbS NWs is up to 660 cm(2)/(V s) at room temperature, in agreement with a long minority carrier diffusion length measured by scanning photocurrent microscopy (SPCM). Interestingly, we have observed a strong dependence of minority carrier diffusion length on gate voltage, which can be understood by considering a carrier concentration dependent recombination lifetime. The demonstrated ambipolar doping of high quality PbS NWs opens up exciting avenues for their applications in photodetectors and photovoltaics.

  4. Few-mode erbium-doped fiber amplifier with photonic lantern for pump spatial mode control.

    PubMed

    Lopez-Galmiche, G; Sanjabi Eznaveh, Z; Antonio-Lopez, J E; Velazquez Benitez, A M; Rodriguez Asomoza, J; Sanchez Mondragon, J J; Gonnet, C; Sillard, P; Li, G; Schülzgen, A; Okonkwo, C M; Amezcua Correa, R

    2016-06-01

    We demonstrate a few-mode erbium-doped fiber amplifier employing a mode-selective photonic lantern for controlling the modal content of the pump light. Amplification of six spatial modes in a 5 m long erbium-doped fiber to ∼6.2  dBm average power is obtained while maintaining high modal fidelity. Through mode-selective forward pumping of the two degenerate LP21 modes operating at 976 nm, differential modal gains of <1  dB between all modes and signal gains of ∼16  dB at 1550 nm are achieved. In addition, low differential modal gain for near-full C-band operation is demonstrated.

  5. 12 CFR 24.1 - Authority, purpose, and OMB control number.

    Code of Federal Regulations, 2010 CFR

    2010-01-01

    ... AND ECONOMIC DEVELOPMENT ENTITIES, COMMUNITY DEVELOPMENT PROJECTS, AND OTHER PUBLIC WELFARE INVESTMENTS § 24.1 Authority, purpose, and OMB control number. (a) Authority. The Office of the Comptroller of... national bank to make investments described in § 24.3, consistent with safety and soundness. This...

  6. 12 CFR 24.1 - Authority, purpose, and OMB control number.

    Code of Federal Regulations, 2011 CFR

    2011-01-01

    ... AND ECONOMIC DEVELOPMENT ENTITIES, COMMUNITY DEVELOPMENT PROJECTS, AND OTHER PUBLIC WELFARE INVESTMENTS § 24.1 Authority, purpose, and OMB control number. (a) Authority. The Office of the Comptroller of... national bank to make investments described in § 24.3, consistent with safety and soundness. This...

  7. Controllable local modification of fractured Nb-doped SrTiO{sub 3} surfaces.

    SciTech Connect

    Chien, T. Y.; Santos, T. S.; Bode, M.; Guisinger, N. P.; Freeland, J. W.

    2009-01-01

    Nanoscale surface modification of a fractured Nb-doped SrTiO{sub 3} surface is demonstrated in a controlled way by scanning tunneling microscopy. By applying positive voltage pulses, holes can be created and the width and depth of the hole can be controlled by selecting the appropriate bias and pulse duration. The process shows a threshold condition for creation of the holes and change in the local electronic density of state consistent with exposure of the underlying TiO{sub 2} layer by removal of SrO. By applying negative bias, the hole can be partially refilled from the transfer of adsorbates on the tip.

  8. Ultrafast optical control of magnetization dynamics in polycrystalline bismuth doped iron garnet thin films

    SciTech Connect

    Deb, Marwan Vomir, Mircea; Rehspringer, Jean-Luc; Bigot, Jean-Yves

    2015-12-21

    Controlling the magnetization dynamics on the femtosecond timescale is of fundamental importance for integrated opto-spintronic devices. For industrial perspectives, it requires to develop simple growth techniques for obtaining large area magneto-optical materials having a high amplitude ultrafast Faraday or Kerr response. Here we report on optical pump probe studies of light induced spin dynamics in high quality bismuth doped iron garnet polycrystalline film prepared by the spin coating method. We demonstrate an ultrafast non-thermal optical control of the spin dynamics using both circularly and linearly polarized pulses.

  9. Growth of optical-quality anthracene crystals doped with dibenzoterrylene for controlled single photon production

    SciTech Connect

    Major, Kyle D. Lien, Yu-Hung; Polisseni, Claudio; Grandi, Samuele; Kho, Kiang Wei; Clark, Alex S.; Hwang, J.; Hinds, E. A.

    2015-08-15

    Dibenzoterrylene (DBT) molecules within a crystalline anthracene matrix show promise as quantum emitters for controlled, single photon production. We present the design and construction of a chamber in which we reproducibly grow doped anthracene crystals of optical quality that are several mm across and a few μm thick. We demonstrate control of the DBT concentration over the range 6–300 parts per trillion and show that these DBT molecules are stable single-photon emitters. We interpret our data with a simple model that provides some information on the vapour pressure of DBT.

  10. Electric-field control of spin-orbit torque in a magnetically doped topological insulator

    NASA Astrophysics Data System (ADS)

    Fan, Yabin; Kou, Xufeng; Upadhyaya, Pramey; Shao, Qiming; Pan, Lei; Lang, Murong; Che, Xiaoyu; Tang, Jianshi; Montazeri, Mohammad; Murata, Koichi; Chang, Li-Te; Akyol, Mustafa; Yu, Guoqiang; Nie, Tianxiao; Wong, Kin L.; Liu, Jun; Wang, Yong; Tserkovnyak, Yaroslav; Wang, Kang L.

    2016-04-01

    Electric-field manipulation of magnetic order has proved of both fundamental and technological importance in spintronic devices. So far, electric-field control of ferromagnetism, magnetization and magnetic anisotropy has been explored in various magnetic materials, but the efficient electric-field control of spin-orbit torque (SOT) still remains elusive. Here, we report the effective electric-field control of a giant SOT in a Cr-doped topological insulator (TI) thin film using a top-gate field-effect transistor structure. The SOT strength can be modulated by a factor of four within the accessible gate voltage range, and it shows strong correlation with the spin-polarized surface current in the film. Furthermore, we demonstrate the magnetization switching by scanning gate voltage with constant current and in-plane magnetic field applied in the film. The effective electric-field control of SOT and the giant spin-torque efficiency in Cr-doped TI may lead to the development of energy-efficient gate-controlled spin-torque devices compatible with modern field-effect semiconductor technologies.

  11. Electric-field control of spin-orbit torque in a magnetically doped topological insulator.

    PubMed

    Fan, Yabin; Kou, Xufeng; Upadhyaya, Pramey; Shao, Qiming; Pan, Lei; Lang, Murong; Che, Xiaoyu; Tang, Jianshi; Montazeri, Mohammad; Murata, Koichi; Chang, Li-Te; Akyol, Mustafa; Yu, Guoqiang; Nie, Tianxiao; Wong, Kin L; Liu, Jun; Wang, Yong; Tserkovnyak, Yaroslav; Wang, Kang L

    2016-04-01

    Electric-field manipulation of magnetic order has proved of both fundamental and technological importance in spintronic devices. So far, electric-field control of ferromagnetism, magnetization and magnetic anisotropy has been explored in various magnetic materials, but the efficient electric-field control of spin-orbit torque (SOT) still remains elusive. Here, we report the effective electric-field control of a giant SOT in a Cr-doped topological insulator (TI) thin film using a top-gate field-effect transistor structure. The SOT strength can be modulated by a factor of four within the accessible gate voltage range, and it shows strong correlation with the spin-polarized surface current in the film. Furthermore, we demonstrate the magnetization switching by scanning gate voltage with constant current and in-plane magnetic field applied in the film. The effective electric-field control of SOT and the giant spin-torque efficiency in Cr-doped TI may lead to the development of energy-efficient gate-controlled spin-torque devices compatible with modern field-effect semiconductor technologies.

  12. Controlled bipolar doping in Cu{sub 3}N (100) thin films

    SciTech Connect

    Matsuzaki, Kosuke Okazaki, Tetsushi; Lee, Yih-Shu; Susaki, Tomofumi; Hosono, Hideo

    2014-12-01

    We have fabricated insulating, p- and n-type Cu{sub 3}N(100) films on SrTiO{sub 3}(100) by plasma assisted molecular beam epitaxy. By controlling the Cu/N flux rate, p-type doping with 10{sup 18}–10{sup 20 }cm{sup −3} in Cu-poor condition and n-type doping with 10{sup 19}–10{sup 20 }cm{sup −3} in N-poor condition were obtained without introducing foreign species. Together with formation of insulating Cu{sub 3}N films with an optical absorption coefficient of ∼10{sup 5 }cm{sup −1} in the photon energy above ∼2.2 eV and an estimated indirect bandgap of ∼1.3 eV, the bipolar doping in Cu{sub 3}N films would be promising for solar energy conversion applications.

  13. Wide-range controllable n-doping of molybdenum disulfide (MoS2) through thermal and optical activation.

    PubMed

    Park, Hyung-Youl; Lim, Myung-Hoon; Jeon, Jeaho; Yoo, Gwangwe; Kang, Dong-Ho; Jang, Sung Kyu; Jeon, Min Hwan; Lee, Youngbin; Cho, Jeong Ho; Yeom, Geun Young; Jung, Woo-Shik; Lee, Jaeho; Park, Seongjun; Lee, Sungjoo; Park, Jin-Hong

    2015-03-24

    Despite growing interest in doping two-dimensional (2D) transition metal dichalcogenides (TMDs) for future layered semiconductor devices, controllability is currently limited to only heavy doping (degenerate regime). This causes 2D materials to act as metallic layers, and an ion implantation technique with precise doping controllability is not available for these materials (e.g., MoS2, MoSe2, WS2, WSe2, graphene). Since adjustment of the electrical and optical properties of 2D materials is possible within a light (nondegenerate) doping regime, a wide-range doping capability including nondegenerate and degenerate regimes is a critical aspect of the design and fabrication of 2D TMD-based electronic and optoelectronic devices. Here, we demonstrate a wide-range controllable n-doping method on a 2D TMD material (exfoliated trilayer and bulk MoS2) with the assistance of a phosphorus silicate glass (PSG) insulating layer, which has the broadest doping range among the results reported to date (between 3.6 × 10(10) and 8.3 × 10(12) cm(-2)) and is also applicable to other 2D semiconductors. This is achieved through (1) a three-step process consisting of, first, dopant out-diffusion between 700 and 900 °C, second, thermal activation at 500 °C, and, third, optical activation above 5 μW steps and (2) weight percentage adjustment of P atoms in PSG (2 and 5 wt %). We anticipate our widely controllable n-doping method to be a starting point for the successful integration of future layered semiconductor devices.

  14. Nitrogen-concentration control in GaNAs/AlGaAs quantum wells using nitrogen δ-doping technique

    SciTech Connect

    Mano, Takaaki; Jo, Masafumi; Kuroda, Takashi; Noda, Takeshi; Sugimoto, Yoshimasa; Sakuma, Yoshiki; Elborg, Martin; Sakoda, Kazuaki

    2014-05-15

    GaNAs/Al{sub 0.35}Ga{sub 0.65}As multiple quantum wells (MQWs) with nitrogen δ-doping were fabricated on GaAs (100) substrates by plasma-assisted molecular beam epitaxy. High controllability of nitrogen-concentrations in the MQWs was achieved by tuning nitrogen δ-doping time. The maximum nitrogen concentration in the MQWs was 2.8%. The MQWs exhibit intense, narrow photoluminescence emission.

  15. Distribution of caffeine levels in urine in different sports in relation to doping control before and after the removal of caffeine from the WADA doping list.

    PubMed

    Van Thuyne, W; Delbeke, F T

    2006-09-01

    Caffeine concentrations were measured in the urine of 4633 athletes tested for doping control in the Ghent Doping Control Laboratory in 2004. Determination of these concentrations was done using an alkaline extraction with a mixture of dichloromethane and methanol (9 : 1; v/v) followed by high performance liquid chromatography and ultraviolet detection (HPLC-UV). The method was validated according to ISO 17 025 standards (International Organisation for Standardisation). Quantification was done by using a linear calibration curve in the range from 0 to 20 microg/ml. The limit of quantification (LOQ) was 0.10 microg/ml. Because the results were not normally distributed, transformation of the data was done to evaluate the difference in detected concentrations in several sports. This resulted in an overall average concentration of 1.12 +/- 2.68 microg/ml. Comparison of the most frequently tested sports in 2004 demonstrated that caffeine concentrations in samples originating from power lifters are significantly higher in comparison to urines taken in other sports. Also, a significant difference between caffeine concentrations found in cycling and concentrations found in other sports, including athletics and some ball sports, was observed. A comparison was made between results obtained in 2004 and results obtained before the removal of caffeine from the WADA (World Anti-Doping Agency) doping list indicating that average caffeine concentrations decreased after the withdrawal of caffeine from the list of prohibited substances. The overall percentage of positive samples between the two periods remained the same although the percentage of positive samples noticed in cycling increased after the removal of caffeine from the doping list.

  16. Gain competition induced mode evolution and resonance control in erbium-doped whispering-gallery microresonators.

    PubMed

    Liu, Xiao-Fei; Lei, Fuchuan; Gao, Ming; Yang, Xu; Wang, Chuan; Özdemir, Şahin Kaya; Yang, Lan; Long, Gui-Lu

    2016-05-01

    Precise control of resonance features in microcavities is of significant importance both for researches and applications. By exploiting gain provided by the doped rare earth ions or Raman gain, this can be achieved through changing the pump. Here we propose and experimentally show that by using gain competition, one can also control the evolution of resonance for the probe signal while the pump is kept unchanged. The transition of Lorentz peak, Fano-like resonance and Lorentz dip can be observed from the transmission spectra of the probe signal through tuning the auxiliary control signal. The theory based on coupled-mode theory and laser rate equations by setting the optical gains as time-dependent was constructed. This method can be used in the precise control of transmission spectra and the coupling regime between the waveguide and microcavities. PMID:27137568

  17. Light controlled drug delivery containers based on spiropyran doped liquid crystal micro spheres

    PubMed Central

    Petriashvili, Gia; Devadze, Lali; Zurabishvili, Tsisana; Sepashvili, Nino; Chubinidze, Ketevan

    2016-01-01

    We have developed a novel, light activated drug delivery containers, based on spiropyran doped liquid crystal micro spheres. Upon exposure to UV/violet light, the spiropyran molecules entrapped inside the nematic liquid crystal micro spheres, interconvert from the hydrophobic, oil soluble form, to the hydrophilic, water soluble merocyanine one, which stimulates the translocation of the merocyanine molecules across the nematic liquid crystal-water barrier and results their homogeneous distribution throughout in an aqueous environment. Light controllable switching property and extremely high solubility of spiropyran in the nematic liquid crystal, promise to elaborate a novel and reliable vehicles for the drug delivery systems. PMID:26977353

  18. Controlling the strontium-doping in calcium phosphate microcapsules through yeast-regulated biomimetic mineralization

    PubMed Central

    Huang, Miaojun; Li, Tianjie; Pan, Ting; Zhao, Naru; Yao, Yongchang; Zhai, Zhichen; Zhou, Jiaan; Du, Chang; Wang, Yingjun

    2016-01-01

    Yeast cells have controllable biosorption on metallic ions during metabolism. However, few studies were dedicated to using yeast-regulated biomimetic mineralization process to control the strontium-doped positions in calcium phosphate microcapsules. In this study, the yeast cells were allowed to pre-adsorb strontium ions metabolically and then served as sacrificing template for the precipitation and calcination of mineral shell. The pre-adsorption enabled the microorganism to enrich of strontium ions into the inner part of the microcapsules, which ensured a slow-release profile of the trace element from the microcapsule. The co-culture with human marrow stromal cells showed that gene expressions of alkaline phosphatase and Collagen-I were promoted. The promotion of osteogenic differentiation was further confirmed in the 3D culture of cell-material complexes. The strategy using living microorganism as ‘smart doping apparatus’ to control incorporation of trace element into calcium phosphate paved a pathway to new functional materials for hard tissue regeneration. PMID:27699057

  19. Controlling the strontium-doping in calcium phosphate microcapsules through yeast-regulated biomimetic mineralization

    PubMed Central

    Huang, Miaojun; Li, Tianjie; Pan, Ting; Zhao, Naru; Yao, Yongchang; Zhai, Zhichen; Zhou, Jiaan; Du, Chang; Wang, Yingjun

    2016-01-01

    Yeast cells have controllable biosorption on metallic ions during metabolism. However, few studies were dedicated to using yeast-regulated biomimetic mineralization process to control the strontium-doped positions in calcium phosphate microcapsules. In this study, the yeast cells were allowed to pre-adsorb strontium ions metabolically and then served as sacrificing template for the precipitation and calcination of mineral shell. The pre-adsorption enabled the microorganism to enrich of strontium ions into the inner part of the microcapsules, which ensured a slow-release profile of the trace element from the microcapsule. The co-culture with human marrow stromal cells showed that gene expressions of alkaline phosphatase and Collagen-I were promoted. The promotion of osteogenic differentiation was further confirmed in the 3D culture of cell-material complexes. The strategy using living microorganism as ‘smart doping apparatus’ to control incorporation of trace element into calcium phosphate paved a pathway to new functional materials for hard tissue regeneration.

  20. Controllable synthesis of Cu-doped CoO hierarchical structure for high performance lithium-ion battery

    NASA Astrophysics Data System (ADS)

    Chen, Chengcheng; Huang, Yanan; Zhang, Hao; Wang, Xiaofeng; Wang, Yijing; Jiao, Lifang; Yuan, Huatang

    2016-05-01

    We report on the strategy of Cu doping inducing the nanosize effect of CoO and their application as anode for lithium ion batteries. With an increase of Cu-doped amount, the structures and morphologies of CoO have special changes. The 0.05 mol Cu-doped CoO shows straw-like bundle structure assembled by nanorods, and the nanorods consist of ultra small nanoparticles (about 6-8 nm). Meanwhile, it shows an excellent rates performance and cycle life. The capacity of 800 mA h g-1 is obtained at 0.5 C after 80 cycles. The highest discharge capacity is 580 mA h g-1 at 10 C and the discharge capacities are relatively stable for 1000 cycles as an anode for Li-ion battery. Therefore, the controllable Cu-doped CoO composite could be deemed to be a potential candidate as an anode material.

  1. Monitoring 2-phenylethanamine and 2-(3-hydroxyphenyl)acetamide sulfate in doping controls.

    PubMed

    Sigmund, Gerd; Dib, Josef; Tretzel, Laura; Piper, Thomas; Bosse, Christina; Schänzer, Wilhelm; Thevis, Mario

    2015-01-01

    2-Phenylethanamine (phenethylamine, PEA) represents the core structure of numerous drugs with stimulant-like properties and is explicitly featured as so-called specified substance on the World Anti-Doping Agency (WADA) Prohibited List. Due to its natural occurrence in humans as well as its presence in dietary products, studies concerning the ability of test methods to differentiate between an illicit intake and the renal elimination of endogenously produced PEA were indicated. Following the addition of PEA to the Prohibited List in January 2015, retrospective evaluation of routine doping control data of 10 190 urine samples generated by combined gas chromatography-mass spectrometry and nitrogen phosphorus-specific detection (GC-MS/NPD) was performed. Signals for PEA at approximate concentrations > 500 ng/mL were observed in 31 cases (0.3%), which were subjected to a validated isotope-dilution liquid chromatography-tandem mass spectrometry (ID-LC-MS/MS) test method for accurate quantification of the target analyte. Further, using elimination study urine samples collected after a single oral administration of 250 mg of PEA hydrochloride to two healthy male volunteers, two tentatively identified metabolites of PEA were observed and evaluated concerning their utility as discriminative markers for PEA intake. The ID-LC-MS/MS approach was extended to allow for the simultaneous detection of PEA and 2-(3-hydroxyphenyl)acetamide sulfate (M1), and concentration ratios of M1 and PEA were calculated for elimination study urine samples and a total of 205 doping control urine samples that returned findings for PEA at estimated concentrations of 50-2500 ng/mL. Urine samples of the elimination study with PEA yielded concentration ratios of M1/PEA up to values of 9.4. Notably, the urinary concentration of PEA did increase with the intake of PEA only to a modest extent, suggesting a comprehensive metabolism of the orally administered substance. Conversely, doping control

  2. Monitoring 2-phenylethanamine and 2-(3-hydroxyphenyl)acetamide sulfate in doping controls.

    PubMed

    Sigmund, Gerd; Dib, Josef; Tretzel, Laura; Piper, Thomas; Bosse, Christina; Schänzer, Wilhelm; Thevis, Mario

    2015-01-01

    2-Phenylethanamine (phenethylamine, PEA) represents the core structure of numerous drugs with stimulant-like properties and is explicitly featured as so-called specified substance on the World Anti-Doping Agency (WADA) Prohibited List. Due to its natural occurrence in humans as well as its presence in dietary products, studies concerning the ability of test methods to differentiate between an illicit intake and the renal elimination of endogenously produced PEA were indicated. Following the addition of PEA to the Prohibited List in January 2015, retrospective evaluation of routine doping control data of 10 190 urine samples generated by combined gas chromatography-mass spectrometry and nitrogen phosphorus-specific detection (GC-MS/NPD) was performed. Signals for PEA at approximate concentrations > 500 ng/mL were observed in 31 cases (0.3%), which were subjected to a validated isotope-dilution liquid chromatography-tandem mass spectrometry (ID-LC-MS/MS) test method for accurate quantification of the target analyte. Further, using elimination study urine samples collected after a single oral administration of 250 mg of PEA hydrochloride to two healthy male volunteers, two tentatively identified metabolites of PEA were observed and evaluated concerning their utility as discriminative markers for PEA intake. The ID-LC-MS/MS approach was extended to allow for the simultaneous detection of PEA and 2-(3-hydroxyphenyl)acetamide sulfate (M1), and concentration ratios of M1 and PEA were calculated for elimination study urine samples and a total of 205 doping control urine samples that returned findings for PEA at estimated concentrations of 50-2500 ng/mL. Urine samples of the elimination study with PEA yielded concentration ratios of M1/PEA up to values of 9.4. Notably, the urinary concentration of PEA did increase with the intake of PEA only to a modest extent, suggesting a comprehensive metabolism of the orally administered substance. Conversely, doping control

  3. Doping control of Cu in pH-tuned hydrothermal growth of ZnO nanowires

    NASA Astrophysics Data System (ADS)

    Lee, Jin-su; Lee, Yong-min; Boo, Jin-Hyo

    2015-11-01

    Un-doped and Cu-doped ZnO nanowires were grown on glass substrates by hydrothermal method. To investigate the effect of pH values on dopant concentration and distribution in the as-grown ZnO nanowires, we carried out hydrothermal process in conjunction with controlling pH values ranging from 5.5 to 7.0. The results show that the disorder and chemical impurity induced lattice distortion are clearly affected by pH values. In Cu 2p3/2 core level, Cu element has a mixed valence state (Cu+, Cu2+). Cu2+ state rather than Cu+ was greatly affected by pH value of solution, resulting in controlled dopant concentration. As such, the dopant concentration is highest at 5.5 of pH, which was confirmed by X-ray diffractometry and micro-Raman spectroscopy. In addition, energy dispersive X-ray spectroscopic elemental mapping indicates the uniform distribution of Cu in ZnO nanowires.

  4. Controllable Synthesis and Tunable Photocatalytic Properties of Ti3+-doped TiO2

    PubMed Central

    Ren, Ren; Wen, Zhenhai; Cui, Shumao; Hou, Yang; Guo, Xiaoru; Chen, Junhong

    2015-01-01

    Photocatalysts show great potential in environmental remediation and water splitting using either artificial or natural light. Titanium dioxide (TiO2)-based photocatalysts are studied most frequently because they are stable, non-toxic, readily available, and highly efficient. However, the relatively wide band gap of TiO2 significantly limits its use under visible light or solar light. We herein report a facile route for controllable synthesis of Ti3+-doped TiO2 with tunable photocatalytic properties using a hydrothermal method with varying amounts of reductant, i.e., sodium borohydride (NaBH4). The resulting TiO2 showed color changes from light yellow, light grey, to dark grey with the increasing amount of NaBH4. The present method can controllably and effectively reduce Ti4+ on the surface of TiO2 and induce partial transformation of anatase TiO2 to rutile TiO2, with the evolution of nanoparticles into hierarchical structures attributable to a high pressure and strong alkali environment in the synthesis atmosphere; in this way, the photocatalytic activity of Ti3+-doped TiO2 under visible-light can be tuned. The as-developed strategy may open up a new avenue for designing and functionalizing TiO2 materials for enhancing visible light absorption, narrowing band gap, and improving photocatalytic activity. PMID:26044406

  5. Controllable Synthesis and Tunable Photocatalytic Properties of Ti(3+)-doped TiO2.

    PubMed

    Ren, Ren; Wen, Zhenhai; Cui, Shumao; Hou, Yang; Guo, Xiaoru; Chen, Junhong

    2015-06-05

    Photocatalysts show great potential in environmental remediation and water splitting using either artificial or natural light. Titanium dioxide (TiO2)-based photocatalysts are studied most frequently because they are stable, non-toxic, readily available, and highly efficient. However, the relatively wide band gap of TiO2 significantly limits its use under visible light or solar light. We herein report a facile route for controllable synthesis of Ti(3+)-doped TiO2 with tunable photocatalytic properties using a hydrothermal method with varying amounts of reductant, i.e., sodium borohydride (NaBH4). The resulting TiO2 showed color changes from light yellow, light grey, to dark grey with the increasing amount of NaBH4. The present method can controllably and effectively reduce Ti(4+) on the surface of TiO2 and induce partial transformation of anatase TiO2 to rutile TiO2, with the evolution of nanoparticles into hierarchical structures attributable to a high pressure and strong alkali environment in the synthesis atmosphere; in this way, the photocatalytic activity of Ti(3+)-doped TiO2 under visible-light can be tuned. The as-developed strategy may open up a new avenue for designing and functionalizing TiO2 materials for enhancing visible light absorption, narrowing band gap, and improving photocatalytic activity.

  6. Orion Multi Purpose Crew Vehicle Environmental Control and Life Support Development Status

    NASA Technical Reports Server (NTRS)

    Lewis, John F.; Barido, Richard A.; Cross, Cynthia D.; Carrasquillo, Robyn; Rains, George Edward

    2012-01-01

    The Orion Multi Purpose Crew Vehicle (MPCV) is the first crew transport vehicle to be developed by the National Aeronautics and Space Administration (NASA) in the last thirty years. Orion is currently being developed to transport the crew safely from the Earth beyond Earth orbit. This year, the vehicle focused on building the Exploration Flight Test 1 (EFT1) vehicle to be launched in 2014. The development of the Orion Environmental Control and Life Support (ECLS) System, focused on the components which are on EFT1 which includes pressure control and active thermal control systems, is progressing through the design stage into manufacturing. Additional development work was done to keep the remaining component progressing towards implementation for a flight tests in 2017 and in 2020. This paper covers the Orion ECLS development from April 2011 to April 2012.

  7. Multi Purpose Crew Vehicle Environmental Control and Life Support Development Status

    NASA Technical Reports Server (NTRS)

    Lewis, John F.; Barido, Richard A.; Cross, Cynthia D.; Carrasquillo, Robyn; Rains, George Edward

    2011-01-01

    The Orion Multi Purpose Crew Vehicle (MPCV) is the first crew transport vehicle to be developed by the National Aeronautics and Space Administration (NASA) in the last thirty years. Orion is currently being developed to transport the crew safely from the Earth beyond Earth orbit. This year, the vehicle focused on building the Orion Flight Test 1 (OFT1) vehicle to be launched in 2013. The development of the Orion Environmental Control and Life Support (ECLS) System, focused on the components which are on OFT1 which includes pressure control and active thermal control systems, is progressing through the design stage into manufacturing. Additional development work was done to keep the remaining component progressing towards implementation for a flight test in 2017. This paper covers the Orion ECLS development from April 2011 to April 2012.

  8. Experimental Approach to Controllably Vary Protein Oxidation While Minimizing Electrode Adsorption for Boron-Doped Diamond Electrochemical Surface Mapping Applications

    SciTech Connect

    McClintock, Carlee; Hettich, Robert {Bob} L

    2013-01-01

    Oxidative protein surface mapping has become a powerful approach for measuring the solvent accessibility of folded protein structures. A variety of techniques exist for generating the key reagent hydroxyl radicals for these measurements; however, many of these approaches require use of radioactive sources or caustic oxidizing chemicals. The purpose of this research was to evaluate and optimize the use of boron-doped diamond (BDD) electrochemistry as a highly accessible tool for producing hydroxyl radicals as a means to induce a controllable level of oxidation on a range of intact proteins. These experiments utilize a relatively high flow rates to reduce protein residence time inside the electrochemical flow chamber, along with a unique cell activation approach to improve control over the intact protein oxidation yield. Studies were conducted to evaluate the level of protein adsorption onto the electrode surface. This report demonstrates a robust protocol for the use of BDD electrochemistry and high performance LC-MS/MS as a high-throughput experimental pipeline for probing higher order protein structure, and illustrates how it is complementary to predictive computational modeling efforts.

  9. Current status and bioanalytical challenges in the detection of unknown anabolic androgenic steroids in doping control analysis.

    PubMed

    Pozo, Oscar J; De Brabanter, Nik; Fabregat, Andreu; Segura, Jordi; Ventura, Rosa; Van Eenoo, Peter; Deventer, Koen

    2013-11-01

    Androgenic anabolic steroids (AAS) are prohibited in sports due to their anabolic effects. Doping control laboratories usually face the screening of AAS misuse by target methods based on MS detection. Although these methods allow for the sensitive and specific detection of targeted compounds and metabolites, the rest remain undetectable. This fact opens a door for cheaters, since different AAS can be synthesized in order to evade doping control tests. This situation was evidenced in 2003 with the discovery of the designer steroid tetrahydrogestrinone. One decade after this discovery, the detection of unknown AAS still remains one of the main analytical challenges in the doping control field. In this manuscript, the current situation in the detection of unknown AAS is reviewed. Although important steps have been made in order to minimize this analytical problem and different analytical strategies have been proposed, there are still some drawbacks related to each approach.

  10. Understanding and control of bipolar self-doping in copper nitride

    NASA Astrophysics Data System (ADS)

    Fioretti, Angela N.; Schwartz, Craig P.; Vinson, John; Nordlund, Dennis; Prendergast, David; Tamboli, Adele C.; Caskey, Christopher M.; Tuomisto, Filip; Linez, Florence; Christensen, Steven T.; Toberer, Eric S.; Lany, Stephan; Zakutayev, Andriy

    2016-05-01

    Semiconductor materials that can be doped both n-type and p-type are desirable for diode-based applications and transistor technology. Copper nitride (Cu3N) is a metastable semiconductor with a solar-relevant bandgap that has been reported to exhibit bipolar doping behavior. However, deeper understanding and better control of the mechanism behind this behavior in Cu3N is currently lacking in the literature. In this work, we use combinatorial growth with a temperature gradient to demonstrate both conduction types of phase-pure, sputter-deposited Cu3N thin films. Room temperature Hall effect and Seebeck effect measurements show n-type Cu3N with 1017 electrons/cm3 for low growth temperature (≈35 °C) and p-type with 1015 holes/cm3-1016 holes/cm3 for elevated growth temperatures (50 °C-120 °C). Mobility for both types of Cu3N was ≈0.1 cm2/Vs-1 cm2/Vs. Additionally, temperature-dependent Hall effect measurements indicate that ionized defects are an important scattering mechanism in p-type films. By combining X-ray absorption spectroscopy and first-principles defect theory, we determined that VCu defects form preferentially in p-type Cu3N, while Cui defects form preferentially in n-type Cu3N, suggesting that Cu3N is a compensated semiconductor with conductivity type resulting from a balance between donor and acceptor defects. Based on these theoretical and experimental results, we propose a kinetic defect formation mechanism for bipolar doping in Cu3N that is also supported by positron annihilation experiments. Overall, the results of this work highlight the importance of kinetic processes in the defect physics of metastable materials and provide a framework that can be applied when considering the properties of such materials in general.

  11. Understanding and Control of Bipolar Self-Doping in Copper Nitride

    PubMed Central

    Fioretti, Angela N.; Schwartz, Craig P.; Vinson, John; Nordlund, Dennis; Prendergast, David; Tamboli, Adele C.; Caskey, Christopher M.; Tuomisto, Filip; Linez, Florence; Christensen, Steven T.; Toberer, Eric S.; Lany, Stephan; Zakutayev, Andriy

    2016-01-01

    Semiconductor materials that can be doped both n-type and p-type are desirable for diode-based applications and transistor technology. Copper nitride (Cu3N) is a metastable semiconductor with a solar-relevant bandgap that has been reported to exhibit bipolar doping behavior. However, deeper understanding and better control of the mechanism behind this behavior in Cu3N is currently lacking in the literature. In this work, we use combinatorial growth with a temperature gradient to demonstrate both conduction types of phase-pure, sputter-deposited Cu3N thin films. Room temperature Hall effect and Seebeck effect measurements show n-type Cu3N with an electron density of 1017 cm−3 for low growth temperature (≈ 35 °C) and p-type with a hole density between 1015 cm−3 and 1016 cm−3 for elevated growth temperatures (50 °C to 120 °C). Mobility for both types of Cu3N was ≈ 0.1 cm2/Vs to 1 cm2/V. Additionally, temperature-dependent Hall effect measurements indicate that ionized defects are an important scattering mechanism in p-type films. By combining X-ray absorption spectroscopy and first-principles defect theory, we determined that VCu defects form preferentially in p-type Cu3N while Cui defects form preferentially in n-type Cu3N; suggesting that Cu3N is a compensated semiconductor with conductivity type resulting from a balance between donor and acceptor defects. Based on these theoretical and experimental results, we propose a kinetic defect formation mechanism for bipolar doping in Cu3N, that is also supported by positron annihilation experiments. Overall, the results of this work highlight the importance of kinetic processes in the defect physics of metastable materials, and provide a framework that can be applied when considering the properties of such materials in general. PMID:27746508

  12. Controlled axial and radial Te-doping of GaAs nanowires

    NASA Astrophysics Data System (ADS)

    Salehzadeh, O.; Kavanagh, K. L.; Watkins, S. P.

    2012-09-01

    Tellurium (Te)-doping of Au-catalyzed GaAs nanowires (NWs) grown by metalorganic vapor phase epitaxy (MOVPE) via the vapor-liquid-solid (VLS) mechanism is presented. Electrical measurements were performed inside a scanning electron microscope by contacting a tungsten nanoprobe to the Au end of individual NWs grown on a heavily n-type GaAs substrate. Rectifying current-voltage (I-V) characteristics are observed due to the formation of a junction at the Au nanoparticle (NP)/NW interface. The electron concentration ne and contact barrier heights, φ0b, were determined from the analyses of these characteristics. As expected, φ0b increased (from 0.63 ± 0.03 eV to 0.71 ± 0.02 eV) with decreasing Te-precursor flow rate, corresponding to a decrease in ne from (9 ± 1) × 1017 cm-3 to (1.5 ± 0.5) × 1017 cm-3. Meanwhile, undoped NWs had space-charge-limited characteristics. There was a large influence of the residual gallium (Ga) in the NP, on barrier properties, controlled by the group V precursor flow (on or off) during the cooling of the NW sample at the end of the growth process. With the group V flow off during cooling, a decrease in φ0b from 0.79 ± 0.04 eV to 0.63 ± 0.03 eV is observed consistent with a higher Ga alloy concentration in the NP, confirmed by energy dispersive spectroscopy measurements. We also demonstrate the fabrication of core/shell, undoped/Te-doped, GaAs NWs with very high Te doping (˜1019 cm-3).

  13. Operation of general purpose stepping motor controllers at the National Synchrotron Light Source

    SciTech Connect

    Stubblefield, F.W.

    1986-10-01

    A prototype and four copies of a general purpose subsystem for mechanical positioning of detectors, samples, and beam line optical elements which constitute experiments at the National Synchrotron Light Source facility of Brookhaven National Laboratory have been constructed and placed into operation. Construction of a sixth subsystem is nearing completion. The subsystems effect mechanical positioning by controlling a set of stepping motors and their associated position encoders. The units are general purpose in the sense that they receive commands over a standard 9600 baud asynchronous serial line compatible with the RS-232-C electrical signal standard, generate TTL-compatible streams of stepping pulses which can be used with a wide variety of stepping motors, and read back position values from a number of different types and models of position encoder. The basic structure of the motor controller subsystem will be briefly reviewed. Short descriptions of the positioning apparatus actuated at each of the test and experiment stations employing a motor control unit are given. Additions and enhancements to the subsystem made in response to problems indicated by actual operation of the four installed units are described in more detail.

  14. Operation of general purpose stepping motor controllers at the National Synchrotron Light Source

    SciTech Connect

    Stubblefield, F.W.

    1987-02-01

    A prototype and four copies of a general purpose subsystem for mechanical positioning of detectors, samples, and beam line optical elements which constitute experiments at the National Synchrotron Light Source facility of Brookhaven National Laboratory have been constructed and placed into operation. Construction of a sixth subsystem is nearing completion. The subsystems effect mechanical positioning by controlling a set of stepping motors and their associated position encoders. The units are general purpose in the sense that they receive commands over a standard 9600 baud asynchronous serial line compatible with the RS-232-C electrical signal standard, generate TTL-compatible streams of stepping pulses which can be used with a wide variety of stepping motors, and read back position values from a number of different types and models of position encoder. The basic structure of the motor controller subsystem is briefly reviewed. Short descriptions of the positioning apparatus actuated at each of the test and experiment stations employing a motor control unit are given. Additions and enhancements to the sub-system made in response to problems indicated by actual operation of the four installed units are described in more detail.

  15. Alignment and structural control of nitrogen-doped carbon nanotubes by utilizing precursor concentration effect

    NASA Astrophysics Data System (ADS)

    Deng, Weina; Chen, Xiaohua; Chen, Xian; Liu, Zheng; Zeng, Ying; Hu, Aiping; Xiong, Yina; Li, Zhe; Tang, Qunli

    2014-11-01

    Nitrogen-doped carbon nanotubes (NCNTs) were prepared using a simple ultrasonic spray pyrolysis method. The precursor concentration effect was examined to effectively control alignment, open tip and diameter of the NCNTs by changing xylene/cyclohexylamine ratio. The structure and morphology of the resultant NCNTs were characterized by scanning electron microscopy, transmission electron microscopy and x-ray photoelectron spectroscopy. The degree of alignment and the diameter of the NCNTs increased as the xylene/cyclohexylamine precursor mixture was changed from 0 to 35% cyclohexylamine. This precursor composition also caused a large number of open-ended nanotubes to form with graphite layers inside the cavities of the NCNTs. However, further increase cyclohexylamine content in the precursor reduced the degree of alignment and diameter of the NCNTs. We demonstrate control over the NCNT alignment and diameter, along with the formation of open-ended nanotube tips, and propose a growth mechanism to understand how these properties are interlinked.

  16. Alignment and structural control of nitrogen-doped carbon nanotubes by utilizing precursor concentration effect.

    PubMed

    Deng, Weina; Chen, Xiaohua; Chen, Xian; Liu, Zheng; Zeng, Ying; Hu, Aiping; Xiong, Yina; Li, Zhe; Tang, Qunli

    2014-11-28

    Nitrogen-doped carbon nanotubes (NCNTs) were prepared using a simple ultrasonic spray pyrolysis method. The precursor concentration effect was examined to effectively control alignment, open tip and diameter of the NCNTs by changing xylene/cyclohexylamine ratio. The structure and morphology of the resultant NCNTs were characterized by scanning electron microscopy, transmission electron microscopy and x-ray photoelectron spectroscopy. The degree of alignment and the diameter of the NCNTs increased as the xylene/cyclohexylamine precursor mixture was changed from 0 to 35% cyclohexylamine. This precursor composition also caused a large number of open-ended nanotubes to form with graphite layers inside the cavities of the NCNTs. However, further increase cyclohexylamine content in the precursor reduced the degree of alignment and diameter of the NCNTs. We demonstrate control over the NCNT alignment and diameter, along with the formation of open-ended nanotube tips, and propose a growth mechanism to understand how these properties are interlinked.

  17. Method for continuous control of composition and doping of pulsed laser deposited films

    DOEpatents

    Lowndes, Douglas H.; McCamy, James W.

    1995-01-01

    A method for growing a deposit upon a substrate of semiconductor material involves the utilization of pulsed laser deposition techniques within a low-pressure gas environment. The substrate and a target of a first material are positioned within a deposition chamber and a low-pressure gas atmosphere is developed within the chamber. The substrate is then heated, and the target is irradiated, so that atoms of the target material are ablated from the remainder of the target, while atoms of the gas simultaneously are adsorbed on the substrate/film surface. The ablated atoms build up upon the substrate, together with the adsorbed gas atoms to form the thin-film deposit on the substrate. By controlling the pressure of the gas of the chamber atmosphere, the composition of the formed deposit can be controlled, and films of continuously variable composition or doping can be grown from a single target of fixed composition.

  18. Temperature sensitivity analysis of polarity controlled electrostatically doped tunnel field-effect transistor

    NASA Astrophysics Data System (ADS)

    Nigam, Kaushal; Pandey, Sunil; Kondekar, P. N.; Sharma, Dheeraj

    2016-09-01

    The conventional tunnel field-effect transistors (TFETs) have shown potential to scale down in sub-22 nm regime due to its lower sub-threshold slope and robustness against short-channel effects (SCEs), however, sensitivity towards temperature variation is a major concern. Therefore, for the first time, we investigate temperature sensitivity analysis of a polarity controlled electrostatically doped tunnel field-effect transistor (ED-TFET). Different performance metrics and analog/RF figure-of-merits were considered and compared for both devices, and simulations were performed using Silvaco ATLAS device tool. We found that the variation in ON-state current in ED-TFET is almost temperature independent due to electrostatically doped mechanism, while, it increases in conventional TFET at higher temperature. Above room temperature, the variation in ION, IOFF, and SS sensitivity in ED-TFET are only 0.11%/K, 2.21%/K, and 0.63%/K, while, in conventional TFET the variations are 0.43%/K, 2.99%/K, and 0.71%/K, respectively. However, below room temperature, the variation in ED-TFET ION is 0.195%/K compared to 0.27%/K of conventional TFET. Moreover, it is analysed that the incomplete ionization effect in conventional TFET severely affects the drive current and the threshold voltage, while, ED-TFET remains unaffected. Hence, the proposed ED-TFET is less sensitive towards temperature variation and can be used for cryogenics as well as for high temperature applications.

  19. Self- and dopant diffusion in extrinsic boron doped isotopically controlled silicon multilayer structures

    SciTech Connect

    Sharp, Ian D.; Bracht, Hartmut A.; Silvestri, Hughes H.; Nicols, Samuel P.; Beeman, Jeffrey W.; Hansen, John L.; Nylandsted Larsen, Arne; Haller, Eugene E.

    2002-04-01

    Isotopically controlled silicon multilayer structures were used to measure the enhancement of self- and dopant diffusion in extrinsic boron doped silicon. {sup 30}Si was used as a tracer through a multilayer structure of alternating natural Si and enriched {sup 28}Si layers. Low energy, high resolution secondary ion mass spectrometry (SIMS) allowed for simultaneous measurement of self- and dopant diffusion profiles of samples annealed at temperatures between 850 C and 1100 C. A specially designed ion- implanted amorphous Si surface layer was used as a dopant source to suppress excess defects in the multilayer structure, thereby eliminating transient enhanced diffusion (TED) behavior. Self- and dopant diffusion coefficients, diffusion mechanisms, and native defect charge states were determined from computer-aided modeling, based on differential equations describing the diffusion processes. We present a quantitative description of B diffusion enhanced self-diffusion in silicon and conclude that the diffusion of both B and Si is mainly mediated by neutral and singly positively charged self-interstitials under p-type doping. No significant contribution of vacancies to either B or Si diffusion is observed.

  20. Adolescents’ use of purpose built shade in secondary schools: cluster randomised controlled trial

    PubMed Central

    White, Vanessa; Wakefield, Melanie A; Jamsen, Kris M; White, Victoria; Livingston, Patricia M; English, Dallas R; Simpson, Julie A

    2009-01-01

    Objective To examine whether students use or avoid newly shaded areas created by shade sails installed at schools. Design Cluster randomised controlled trial with secondary schools as the unit of randomisation. Setting 51 secondary schools with limited available shade, in Australia, assessed over two spring and summer terms. Participants Students outside at lunch times. Intervention Purpose built shade sails were installed in winter 2005 at full sun study sites to increase available shade for students in the school grounds. Main outcome measure Mean number of students using the primary study sites during weekly observations at lunch time. Results Over the study period the mean change in students using the primary study site from pre-test to post-test was 2.63 (95% confidence interval 0.87 to 4.39) students in intervention schools and −0.03 (−1.16 to 1.09) students in control schools. The difference in mean change between groups was 2.67 (0.65 to 4.68) students (P=0.011). Conclusions Students used rather than avoided newly shaded areas provided by purpose built shade sails at secondary schools in this trial, suggesting a practical means of reducing adolescents’ exposure to ultraviolet radiation. Trial registration Exempt. PMID:19223344

  1. A human rights view on access to controlled substances for medical purposes under the international drug control framework.

    PubMed

    Gispen, Marie Elske C

    2013-11-01

    The world is confronted with a major public health deficit caused by poor access to controlled essential medicines under the international drug control framework. This is affecting millions of patients on a daily basis and resulting in numerous human rights violations. The present review contextualises this deficit from a human rights perspective. Drug control efforts are informed by a twofold objective stemming from the double nature of scheduled substances: free access for medical purposes should be ensured, though non-medical use of substances such as opium should be restricted. The international drug control framework is, in theory, based on this twofold notion, however at the level of interpretation, monitoring, and implementation, a one-sided emphasis is demonstrated. By tracing a parallel between the obligations of states under the international drug control framework and those that derive from human rights law, the review shows that the two systems seem incoherent and conflicting in nature and flags the importance of cross-disciplinary research into drug control and human rights.

  2. The Anti-Doping Movement.

    PubMed

    Willick, Stuart E; Miller, Geoffrey D; Eichner, Daniel

    2016-03-01

    Historical reports of doping in sports date as far back as the ancient Greek Olympic Games. The anti-doping community considers doping in sports to be cheating and a violation of the spirit of sport. During the past century, there has been an increasing awareness of the extent of doping in sports and the health risks of doping. In response, the anti-doping movement has endeavored to educate athletes and others about the health risks of doping and promote a level playing field. Doping control is now undertaken in most countries around the world and at most elite sports competitions. As athletes have found new ways to dope, however, the anti-doping community has endeavored to strengthen its educational and deterrence efforts. It is incumbent upon sports medicine professionals to understand the health risks of doping and all doping control processes. PMID:26972261

  3. The Anti-Doping Movement.

    PubMed

    Willick, Stuart E; Miller, Geoffrey D; Eichner, Daniel

    2016-03-01

    Historical reports of doping in sports date as far back as the ancient Greek Olympic Games. The anti-doping community considers doping in sports to be cheating and a violation of the spirit of sport. During the past century, there has been an increasing awareness of the extent of doping in sports and the health risks of doping. In response, the anti-doping movement has endeavored to educate athletes and others about the health risks of doping and promote a level playing field. Doping control is now undertaken in most countries around the world and at most elite sports competitions. As athletes have found new ways to dope, however, the anti-doping community has endeavored to strengthen its educational and deterrence efforts. It is incumbent upon sports medicine professionals to understand the health risks of doping and all doping control processes.

  4. Up-conversion luminescence polarization control in Er3+-doped NaYF4 nanocrystals

    NASA Astrophysics Data System (ADS)

    Hui, Zhang; Yun-Hua, Yao; Shi-An, Zhang; Chen-Hui, Lu; Zhen-Rong, Sun

    2016-02-01

    We propose a femtosecond laser polarization modulation scheme to control the up-conversion (UC) luminescence in Er3+-doped NaYF4 nanocrystals dispersed in the silicate glass. We show that the UC luminescence can be suppressed when the laser polarization is changed from linear through elliptical to circular, and the higher repetition rate will yield the lower control efficiency. We theoretically analyze the physical control mechanism of the UC luminescence polarization modulation by considering on- and near-resonant two-photon absorption, energy transfer up-conversion, and excited state absorption, and show that the polarization control mainly comes from the contribution of near-resonant two-photon absorption. Furthermore, we propose a method to improve the polarization control efficiency of UC luminescence in rare-earth ions by applying a two-color femtosecond laser field. Project supported by the Young Scientists Fund of the National Natural Science Foundation of China (Grant No. 11304396), the National Natural Science Foundation of China (Grant Nos. 11474096 and 51132004), and the Shanghai Municipal Science and Technology Commission, China (Grant No. 14JC1401500).

  5. Design, synthesis, and characterization of materials for controlled line deposition, environmental remediation, and doping of porous manganese oxide material

    NASA Astrophysics Data System (ADS)

    Calvert, Craig A.

    This thesis covers three topics: (1) coatings formed from sol-gel phases, (2) environmental remediation, and (3) doping of a porous manganese oxide. Synthesis, characterization, and application were investigated for each topic. Line-formations were formed spontaneously by self-assembly from vanadium sol-gels and other metal containing solutions on glass substrates. The solutions were prepared by the dissolution of metal oxide or salt in water. A more straightforward method is proposed than used in previous work. Analyses using optical microscopy, atomic force microscopy, scanning electron microscopy, energy-dispersive X-ray analysis, and infrared spectroscopy showed discreet lines whose deposition could be controlled by varying the concentration. A mechanism was developed from the observed results. Microwave heating, the addition of graphite rods, and oxidants, can enhance HCB remediation from soil. To achieve remediation, a TeflonRTM vessel open to the atmosphere along with an oxidant, potassium persulfate (PerS) or potassium hydroxide, along with uncoated or aluminum oxide coated, graphite rods were heated in a research grade microwave oven. Microwave heating was used to decrease the heating time, and graphite rods were used to increase the absorption of the microwave energy by providing thermal centers. The results showed that the percent HCB removed was increased by adding graphite rods and oxidants. Tungsten, silver, and sulfur were investigated as doping agents for K--OMS-2. The synthesis of these materials was carried out with a reflux method. The doping of K--OMS-2 led to changes in the properties of a tungsten doped K--OMS-2 had an increased resistivity, the silver doped material showed improved epoxidation of trans-stilbene, and the addition of sulfur produced a paper-like material. Rietveld refinement of the tungsten doped K--OMS-2 showed that the tungsten was doped into the framework.

  6. Hidden possibilities in controlling optical soliton in fiber guided doped resonant medium

    NASA Astrophysics Data System (ADS)

    Kundu, Anjan

    2011-06-01

    Fiber guided optical signal propagating in a Erbium doped nonlinear resonant medium is known to produce cleaner solitonic pulse, described by the self induced transparency (SIT) coupled to nonlinear Schrödinger equation. We discover two new possibilities hidden in its integrable structure, for amplification and control of the optical pulse. Using the variable soliton width permitted by the integrability of this model, the broadening pulse can be regulated by adjusting the initial population inversion of the dopant atoms. The effect can be enhanced by another innovative application of its constrained integrable hierarchy, proposing a system of multiple SIT media. These theoretical predictions are workable analytically in details, correcting a well known result.

  7. Doping in controlling the type of conductivity in bulk and nanostructured thermoelectric materials

    NASA Astrophysics Data System (ADS)

    Fuks, D.; Komisarchik, G.; Kaller, M.; Gelbstein, Y.

    2016-08-01

    Doping of materials for thermoelectric applications is widely used nowadays to control the type of conductivity. We report the results of ab-initio calculations aimed at developing the consistent scheme for determining the role of impurities that may change the type of conductivity in two attractive thermoelectric classes of materials. It is demonstrated that alloying of TiNiSn with Cu makes the material of n-type, and alloying with Fe leads to p-type conductivity. Similar calculations for PbTe with small amount of Na substituting for Pb leads to p-type conductivity, while Cl substituting for Te makes PbTe an n-type material. It is shown also that for nano-grained materials the n-type conductivity should be observed. The effect of impurities segregating to the grain boundaries in nano-structured PbTe is also discussed.

  8. Field effect controlled ferromagnetism in transition metal doped ZnO

    NASA Astrophysics Data System (ADS)

    Bellingeri, E.; Pellegrino, L.; Biasotti, M.; Pallecchi, I.; Canu, G.; Gerbi, A.; Vignolo, M.; Siri, A. S.; Marré, D.; Rusponi, S.; Lehnert, A.; Nolting, F.

    2008-02-01

    The ability to externally control the properties of magnetic materials would be highly desirable both from fundamental and technological point of views. In this respect, dilute magnetic semiconductor (DMS), in which a fraction of atoms of the nonmagnetic semiconductor host is replaced by magnetic ions, have recently attracted broad interest for their potential application in spintronics. In this work, we focused on transition metal (TM) (Co, Mn and Cu) doped Zinc oxide (ZnO) because room temperature ferromagnetism was both theoretically predicted and experimentally observed. However, the origin of such ferromagnetism, in particular whether it is a signature of a true DMS behaviour (long range magnetic interaction between the doping ions) or it arises from the formation of secondary phases, segregation or clustering is still under debate. Measuring the dependence of the magnetic properties on the carrier concentration can clarify the underlying physics. The samples were characterized by resistivity, Hall effect, magnetoresistance, Seebeck effect, synchrotron X-ray adsorption spectra (XAS) and magnetic dichroism (XMD) while modulating the carrier density by electric field. The insulating-gate field-effect transistor structures are realized in ZnO/Strontium Titanate (SrTiO 3) heterostructures by pulsed laser deposition. These devices offers the capability to modulate the carrier density of a probe accessible (light, AFM tip, ...) channel, by more than 5 orders of magnitude (from ~10 15 to ~10 20 e -/cm 3, estimated by Hall effect measurements under FE). The Co and Mn films measured by DC SQUID magnetometer result ferromagnetic and anomalous Hall effect was observed at low temperature but nor ferromagnetic nor antiferromagnetic signal was detectable in the XMD spectra. Cu doped films are insulating and nonmagnetic. Photo Emission Electron Microscopy (x-PEEM) and magnetic force microscopy (MFM) showed that the sample are homogeneus and no clustering of TM were detected

  9. Photon-pair source with controllable delay based on shaped inhomogeneous broadening of rare-earth-metal-doped solids

    SciTech Connect

    Sekatski, Pavel; Sangouard, Nicolas; Gisin, Nicolas; Afzelius, Mikael; Riedmatten, Hugues de

    2011-05-15

    Spontaneous Raman emission in atomic gases provides an attractive source of photon pairs with a controllable delay. We show how this technique can be implemented in solid state systems by appropriately shaping the inhomogeneous broadening. Our proposal is eminently feasible with current technology and provides a realistic solution to entangle remote rare-earth-metal-doped solids in a heralded way.

  10. Shape-controlled synthesis and influence of W doping and oxygen nonstoichiometry on the phase transition of VO2

    PubMed Central

    Chen, Ru; Miao, Lei; Liu, Chengyan; Zhou, Jianhua; Cheng, Haoliang; Asaka, Toru; Iwamoto, Yuji; Tanemura, Sakae

    2015-01-01

    Monoclinic VO2(M) in nanostructure is a prototype material for interpreting correlation effects in solids with fully reversible phase transition and for the advanced applications to smart devices. Here, we report a facile one-step hydrothermal method for the controlled growth of single crystalline VO2(M/R) nanorods. Through tuning the hydrothermal temperature, duration of the hydrothermal time and W-doped level, single crystalline VO2(M/R) nanorods with controlled aspect ratio can be synthesized in large quantities, and the crucial parameter for the shape-controlled synthesis is the W-doped content. The dopant greatly promotes the preferential growth of (110) to form pure phase VO2(R) nanorods with high aspect ratio for the W-doped level = 2.0 at% sample. The shape-controlled process of VO2(M/R) nanorods upon W-doping are systematically studied. Moreover, the phase transition temperature (Tc) of VO2 depending on oxygen nonstoichiometry is investigated in detail. PMID:26373612

  11. Orion Multi-Purpose Crew Vehicle Active Thermal Control and Environmental Control and Life Support Development Status

    NASA Technical Reports Server (NTRS)

    Lewis, John F.; Barido, Richard A.; Boehm, Paul; Cross, Cynthia D.; Rains, George Edward

    2014-01-01

    The Orion Multi Purpose Crew Vehicle (MPCV) is the first crew transport vehicle to be developed by the National Aeronautics and Space Administration (NASA) in the last thirty years. Orion is currently being developed to transport the crew safely beyond Earth orbit. This year, the vehicle focused on building the Exploration Flight Test 1 (EFT1) vehicle to be launched in September of 2014. The development of the Orion Active Thermal Control (ATCS) and Environmental Control and Life Support (ECLS) System, focused on the integrating the components into the EFT1 vehicle and preparing them for launch. Work also has started on preliminary design reviews for the manned vehicle. Additional development work is underway to keep the remaining component progressing towards implementation on the flight tests of EM1 in 2017 and of EM2 in 2020. This paper covers the Orion ECLS development from April 2013 to April 2014.

  12. Authority of compact commission to control import/export for disposal and other purposes

    SciTech Connect

    Poling, R.D.

    1995-12-31

    As operational capabilities for radioactive waste disposal expand and as approaching dates for waste exclusion near, the legal question of the authority of compact commissions to control the import and export of low-level radioactive nuclear waste is a legal issue of significance to many regions. This presentation will review the provisions of various compacts and the federal compact approval legislation, consider the interpretation of the Commerce Clause of the U.S. Constitution, and discuss possible interpretive perspectives relating to the authority of compact commissions. The discussion will focus on whether waste exclusion authority is confined in application to imported waste for permanent disposal or extends to transported and imported waste for processing, treatment, or other purposes.

  13. Measurements, modeling, control and simulation - as applied to the human left ventricle for purposeful physiological monitoring.

    NASA Technical Reports Server (NTRS)

    Ghista, D. N.; Rasmussen, D. N.; Linebarger, R. N.; Sandler, H.

    1971-01-01

    Interdisciplinary engineering research effort in studying the intact human left ventricle has been employed to physiologically monitor the heart and to obtain its 'state-of-health' characteristics. The left ventricle was selected for this purpose because it plays a key role in supplying energy to the body cells. The techniques for measurement of the left ventricular geometry are described; the geometry is effectively displayed to bring out the abnormalities in cardiac function. Methods of mathematical modeling, which make it possible to determine the performance of the intact left ventricular muscle, are also described. Finally, features of a control system for the left ventricle for predicting the effect of certain physiological stress situations on the ventricle performance are discussed.

  14. Control of p-type conduction in Mg doped monophase CuCrO2 thin layers

    NASA Astrophysics Data System (ADS)

    Chikoidze, E.; Boshta, M.; Gomaa, M.; Tchelidze, T.; Daraselia, D.; Japaridze, D.; Shengelaya, A.; Dumont, Y.; Neumann-Spallart, M.

    2016-05-01

    This work aims to clarify the origin of hole conduction in undoped and Mg-doped CuCrO2 oxide in order to have the possibility of controlling it by corresponding growth parameters. A chemical spray pyrolysis procedure for the deposition of p-type semiconductor thin films is described. The as-deposited films were amorphous. The formation of highly crystalline CuCrO2 and Mg-doped CuCrO2 films with a single phase delafossite structure was realized by annealing between 600 °C and 960 °C in a nitrogen atmosphere. The carrier concentration and the point defects of the samples are calculated by using the developed Kroger method of quasi-chemical reactions. p-type conductivity was predicted and observed in the undoped and Mg doped CuCrO2 sample, and with n ~ 1018 cm‑3 carrier concentrations for 4%Mg doping. The electrical resistivity for a 4% Mg doped sample was 1.4 Ω·cm with a Seebeck coefficient of  +130 μV K‑1 at 40 °C. By electroparamagnetic resonance spectroscopy Cr3+ and Cu2+ related defects were studied.

  15. Control of p-type conduction in Mg doped monophase CuCrO2 thin layers

    NASA Astrophysics Data System (ADS)

    Chikoidze, E.; Boshta, M.; Gomaa, M.; Tchelidze, T.; Daraselia, D.; Japaridze, D.; Shengelaya, A.; Dumont, Y.; Neumann-Spallart, M.

    2016-05-01

    This work aims to clarify the origin of hole conduction in undoped and Mg-doped CuCrO2 oxide in order to have the possibility of controlling it by corresponding growth parameters. A chemical spray pyrolysis procedure for the deposition of p-type semiconductor thin films is described. The as-deposited films were amorphous. The formation of highly crystalline CuCrO2 and Mg-doped CuCrO2 films with a single phase delafossite structure was realized by annealing between 600 °C and 960 °C in a nitrogen atmosphere. The carrier concentration and the point defects of the samples are calculated by using the developed Kroger method of quasi-chemical reactions. p-type conductivity was predicted and observed in the undoped and Mg doped CuCrO2 sample, and with n ~ 1018 cm-3 carrier concentrations for 4%Mg doping. The electrical resistivity for a 4% Mg doped sample was 1.4 Ω·cm with a Seebeck coefficient of  +130 μV K-1 at 40 °C. By electroparamagnetic resonance spectroscopy Cr3+ and Cu2+ related defects were studied.

  16. Planar Gallium arsenide nanowire arrays for nanoelectronics: Controlled growth, doping, characterization, and devices

    NASA Astrophysics Data System (ADS)

    Dowdy, Ryan Stewart

    The Vapor-Liquid-Solid (VLS) mechanism is a bottom-up approach to produce onedimensional semiconductor structures, or nanowires. VLS nanowires are formed via a chemical or physical deposition process, where a metallic nanoparticle (seed) facilitates the growth. Nanowire growth diameter is strongly correlated to seed size, therefore top-down patterning can control site location and diameter of nanowire growth. Nanowires are sought after for their potential use as a manageable way produce small dimensioned semiconductor features without the need of expensive lithographic techniques. VLS nanowires commonly grow out-of-plane with respect to their growth substrate, resulting in difficulty with integrating VLS nanowires into existing device processing which is intended for planar geometries. Nanowires are typically removed from the substrate, which requires painstaking and uneconomical methods to pattern and align the nanowires. Planar nanowires are a potential solution to this issue; they grow in-plane on the substrate surface, epitaxially attached along its entire axis. Planar nanowires, as is, can be integrated into any preexisting planar semiconductor process, combining the advantages of nanowires with increased manufacturability. In this dissertation, planar GaAs nanowires are grown using metal organic chemical vapor deposition (MOCVD) with Au nanoparticles as the liquid metal seed. Growth occurs across multiple substrates to elucidate the mechanism behind planar nanowire growth direction. Knowledge gained by observing planar nanowire growth is used to precisely control nanowire growth direction. Subsequently the doping of planar nanowires is explored and unique phenomena related to the p-type doping of planar nanowires are investigated and discussed. The advantages of using planar nanowires are demonstrated through the controlled growth and doping of planar nanowires, and ultimately fabrication of electronic devices using conventional planar process techniques

  17. Performance optimization of p-n homojunction nanowire-based piezoelectric nanogenerators through control of doping concentration

    SciTech Connect

    Liu, Guocheng Ban, Dayan; Abdel-Rahman, Eihab

    2015-09-07

    This paper demonstrates a series of flexible transparent ZnO p-n homojunction nanowire-based piezoelectric nanogenerators (NGs) with different p-doping concentrations. The lithium-doped segments are grown directly and consecutively on top of intrinsic nanowires (n-type). When characterized under cyclic compressive strains, the overall NG performance is enhanced by up to eleven-fold if the doping concentration is properly controlled. This improvement is attributable to reduction in the mobile charge screening effect and optimization of the NGs' internal electrical characteristics. Experimental results also show that an interfacial MoO{sub 3} barrier layer, at an optimized thickness of 5–10 nm, reduces leakage current and substantially improves piezoelectric NG performance.

  18. Process for fabricating device structures for real-time process control of silicon doping

    DOEpatents

    Weiner, Kurt H.

    2001-01-01

    Silicon device structures designed to allow measurement of important doping process parameters immediately after the doping step has occurred. The test structures are processed through contact formation using standard semiconductor fabrication techniques. After the contacts have been formed, the structures are covered by an oxide layer and an aluminum layer. The aluminum layer is then patterned to expose the contact pads and selected regions of the silicon to be doped. Doping is then performed, and the whole structure is annealed with a pulsed excimer laser. But laser annealing, unlike standard annealing techniques, does not effect the aluminum contacts because the laser light is reflected by the aluminum. Once the annealing process is complete, the structures can be probed, using standard techniques, to ascertain data about the doping step. Analysis of the data can be used to determine probable yield reductions due to improper execution of the doping step and thus provide real-time feedback during integrated circuit fabrication.

  19. [Anti-doping control and public health: limits to the exposure of human health to risk in the name of sporting glory].

    PubMed

    Aith, Fernando Mussa Abujamra

    2013-10-01

    Given the current regulatory environment surrounding doping in the world, and in view of the recurring scandals linking leading athletes in a variety of sports with doping, this paper aims to provide some thoughts on the relationship between doping and public health, taking as base reference the risks doping poses to health and considering the regulatory options that have been adopted by the international community and the sports federations to control and supervise this unsporting and risky practice. The text seeks to reflect on the necessary balance between sport and health, as well as on the role of the state in preserving this balance. PMID:24626509

  20. [Anti-doping control and public health: limits to the exposure of human health to risk in the name of sporting glory].

    PubMed

    Aith, Fernando Mussa Abujamra

    2013-10-01

    Given the current regulatory environment surrounding doping in the world, and in view of the recurring scandals linking leading athletes in a variety of sports with doping, this paper aims to provide some thoughts on the relationship between doping and public health, taking as base reference the risks doping poses to health and considering the regulatory options that have been adopted by the international community and the sports federations to control and supervise this unsporting and risky practice. The text seeks to reflect on the necessary balance between sport and health, as well as on the role of the state in preserving this balance.

  1. Untargeted metabolomics in doping control: detection of new markers of testosterone misuse by ultrahigh performance liquid chromatography coupled to high-resolution mass spectrometry.

    PubMed

    Raro, Montse; Ibáñez, María; Gil, Rubén; Fabregat, Andreu; Tudela, Eva; Deventer, Koen; Ventura, Rosa; Segura, Jordi; Marcos, Josep; Kotronoulas, Aristotelis; Joglar, Jesús; Farré, Magi; Yang, Sheng; Xing, Yanyi; Van Eenoo, Peter; Pitarch, Elena; Hernández, Félix; Sancho, Juan Vicente; Pozo, Óscar J

    2015-08-18

    The use of untargeted metabolomics for the discovery of markers is a promising and virtually unexplored tool in the doping control field. Hybrid quadrupole time-of-flight (QTOF) and hybrid quadrupole Orbitrap (Q Exactive) mass spectrometers, coupled to ultrahigh pressure liquid chromatography, are excellent tools for this purpose. In the present work, QTOF and Q Exactive have been used to look for markers for testosterone cypionate misuse by means of untargeted metabolomics. Two different groups of urine samples were analyzed, collected before and after the intramuscular administration of testosterone cypionate. In order to avoid analyte losses in the sample treatment, samples were just 2-fold diluted with water and directly injected into the chromatographic system. Samples were analyzed in both positive and negative ionization modes. Data from both systems were treated under untargeted metabolomic strategies using XCMS application and multivariate analysis. Results from the two mass spectrometers differed in the number of detected features, but both led to the same potential marker for the particular testosterone ester misuse. The in-depth study of the MS and MS/MS behavior of this marker allowed for the establishment of 1-cyclopentenoylglycine as a feasible structure. The putative structure was confirmed by comparison with synthesized material. This potential marker seems to come from the metabolism of the cypionic acid release after hydrolysis of the administered ester. Its suitability for doping control has been evaluated.

  2. Traditional Chinese medicine and sports drug testing: identification of natural steroid administration in doping control urine samples resulting from musk (pod) extracts.

    PubMed

    Thevis, Mario; Schänzer, Wilhelm; Geyer, Hans; Thieme, Detlef; Grosse, Joachim; Rautenberg, Claudia; Flenker, Ulrich; Beuck, Simon; Thomas, Andreas; Holland, Ruben; Dvorak, Jiri

    2013-01-01

    The administration of musk extract, that is, ingredients obtained by extraction of the liquid secreted from the preputial gland or resulting grains of the male musk deer (eg, Moschus moschiferus), has been recommended in Traditional Chinese Medicine (TCM) applications and was listed in the Japanese pharmacopoeia for various indications requiring cardiovascular stimulation, anti-inflammatory medication or androgenic hormone therapy. Numerous steroidal components including cholesterol, 5α-androstane-3,17-dione, 5β-androstane-3,17-dione, androsterone, etiocholanolone, epiandrosterone, 3β-hydroxy-androst-5-en-17-one, androst-4-ene-3,17-dione and the corresponding urea adduct 3α-ureido-androst-4-en-17-one were characterised as natural ingredients of musk over several decades, implicating an issue concerning doping controls if used for the treatment of elite athletes. In the present study, the impact of musk extract administration on sports drug testing results of five females competing in an international sporting event is reported. In the course of routine doping controls, adverse analytical findings concerning the athletes' steroid profile, corroborated by isotope-ratio mass spectrometry (IRMS) data, were obtained. The athletes' medical advisors admitted the prescription of TCM-based musk pod preparations and provided musk pod samples for comparison purposes to clarify the antidoping rule violation. Steroid profiles, IRMS results, literature data and a musk sample obtained from a living musk deer of a local zoo conclusively demonstrated the use of musk pod extracts in all cases which, however, represented a doping offence as prohibited anabolic-androgenic steroids were administered.

  3. Orion Multi-Purpose Crew Vehicle Active Thermal Control and Environmental Control and Life Support Development Status

    NASA Technical Reports Server (NTRS)

    Lewis, John F.; Barido, Richard A.; Cross, Cynthia D.; Rains, George Edward

    2013-01-01

    The Orion Multi-Purpose Crew Vehicle (MPCV) is the first crew transport vehicle to be developed by the National Aeronautics and Space Administration (NASA) in the last thirty years. Orion is currently being developed to transport the crew safely beyond Earth orbit. This year, the vehicle focused on building the Exploration Flight Test 1 (EFT1) vehicle to be launched in 2014. The development of the Orion Environmental Control and Life Support (ECLS) System, focused on the completing the components which are on EFT1. Additional development work has been done to keep the remaining component progressing towards implementation for a flight tests in of EM1 in 2017 and in and EM2 in 2020. This paper covers the Orion ECLS development from April 2012 to April 2013.

  4. Shape controlled Sn doped ZnO nanostructures for tunable optical emission and transport properties

    SciTech Connect

    Rakshit, T.; Manna, I.; Ray, S. K.

    2013-11-15

    Pure and Sn doped ZnO nanostructures have been grown on SiO{sub 2}/Si substrates by vapor-solid technique without using any catalysts. It has been found that the morphology of the nanostructures depend strongly on the growth temperature and doping concentration. By proper tuning of the growth temperature, morphology of pure ZnO can be changed from tetrapods to multipods. On the other hand, by varying the doping concentration of Sn in ZnO, the morphology can be tuned from tetrapods to flower-like multipods to nanowires. X-ray diffraction pattern reveals that the nanostructures have a preferred (0002) growth orientation, and they are tensile strained with the increase of Sn doping in ZnO. Temperature-dependent photoluminescence characteristics of these nanostructures have been investigated in the range from 10 to 300 K. Pure ZnO tetrapods exhibited less defect state emissions than that of pure ZnO multipods. The defect emission is reduced with low concentration of Sn doping, but again increases at higher concentration of doping because of increased defects. Transport properties of pure and Sn doped ZnO tetrapods have been studied using complex-plane impedance spectroscopy. The contribution from the arms and junctions of a tetrapod could be distinguished. Sn doped ZnO samples showed lower conductivity but higher relaxation time than that of pure ZnO tetrapods.

  5. Spatial Control of Laser-Induced Doping Profiles in Graphene on Hexagonal Boron Nitride.

    PubMed

    Neumann, Christoph; Rizzi, Leo; Reichardt, Sven; Terrés, Bernat; Khodkov, Timofiy; Watanabe, Kenji; Taniguchi, Takashi; Beschoten, Bernd; Stampfer, Christoph

    2016-04-13

    We present a method to create and erase spatially resolved doping profiles in graphene-hexagonal boron nitride heterostructures. The technique is based on photoinduced doping by a focused laser beam and does neither require masks nor photoresists. This makes our technique interesting for rapid prototyping of unconventional electronic device schemes, where the spatial resolution of the rewritable, long-term stable doping profiles is limited by only the laser spot size (≈600 nm) and the accuracy of sample positioning. Our optical doping method offers a way to implement and to test different, complex doping patterns in one and the very same graphene device, which is not achievable with conventional gating techniques. PMID:26986938

  6. Selective in-plane nitrogen doping of graphene by an energy-controlled neutral beam

    NASA Astrophysics Data System (ADS)

    Okada, Takeru; Samukawa, Seiji

    2015-12-01

    Nitrogen-doped graphene promises to improve current electronic devices, sensors, and energy-based devices. To this end, the bonding states between carbon and nitrogen atoms can be manipulated to tailor the properties of the doped graphene. For example, graphitic nitrogen is known to promote desired catalytic activities in graphene fuel-cell systems, resulting from a four-electron reaction. However, established nitrogen-doping methods lack selectivity in dopant chemical identity and in dopant location; both are key factors in graphene property design because the properties depend on the chemical identity and location of the dopant. Here, we utilize a nitrogen neutral beam (NB) technique—with exquisite beam energy control—to dope graphene with nitrogen. Using x-ray photoelectron and Raman spectroscopy, we show that the energy of the nitrogen NB not only determines the chemistry of the nitrogen dopant introduced to graphene, but it also dictates the doping locations within graphene layers.

  7. Toward controlling the carrier density of Si doped Ga2O3 films by pulsed laser deposition

    NASA Astrophysics Data System (ADS)

    Zhang, Fabi; Arita, Makoto; Wang, Xu; Chen, Zhengwei; Saito, Katsuhiko; Tanaka, Tooru; Nishio, Mitsuhiro; Motooka, Teruaki; Guo, Qixin

    2016-09-01

    Precise control of dopant composition is critical for the production of semiconductor films with desired properties. Here, we present results on the electrical properties for Si doped Ga2O3 films grown by pulsed laser deposition technique (PLD). The Si composition in the films can be controlled by changing the target composition as observed from the secondary ion mass spectroscopy measurement. The carrier density of the films is varied from the order of 1015 to 1020 cm-3 while the conductivity from 10-4 to 1 S cm-1 as measured by Hall equipment. The carrier density of the films has been verified by Kelvin force microscopy, which shows an increased surface work function with the increase of carrier density. The results suggest that the carrier density of β-Ga2O3 films is controllable by Si doping by PLD, paving a way to develop the Ga2O3 film-based electronic devices.

  8. Controlled Growth of Platinum Nanowire Arrays on Sulfur Doped Graphene as High Performance Electrocatalyst

    PubMed Central

    Wang, Rongyue; Higgins, Drew C.; Hoque, Md Ariful; Lee, DongUn; Hassan, Fathy; Chen, Zhongwei

    2013-01-01

    Graphene supported Pt nanostructures have great potential to be used as catalysts in electrochemical energy conversion and storage technologies; however the simultaneous control of Pt morphology and dispersion, along with ideally tailoring the physical properties of the catalyst support properties has proven very challenging. Using sulfur doped graphene (SG) as a support material, the heterogeneous dopant atoms could serve as nucleation sites allowing for the preparation of SG supported Pt nanowire arrays with ultra-thin diameters (2–5 nm) and dense surface coverage. Detailed investigation of the preparation technique reveals that the structure of the resulting composite could be readily controlled by fine tuning the Pt nanowire nucleation and growth reaction kinetics and the Pt-support interactions, whereby a mechanistic platinum nanowire array growth model is proposed. Electrochemical characterization demonstrates that the composite materials have 2–3 times higher catalytic activities toward the oxygen reduction and methanol oxidation reaction compared with commercial Pt/C catalyst. PMID:23942256

  9. Gain control dynamics of thulium-doped fiber amplifier at 2 μm

    NASA Astrophysics Data System (ADS)

    Khamis, M. A.; Ennser, K.

    2016-02-01

    This work is novel in that it explains the modeling and simulation of a thulium-doped fiber amplifier (TDFA) in a reconfigurable wavelength division multiplexing (WDM) system operating at 2 μm. We use the optical gain-clamping technique in order to control gain amplification and eliminate deleterious channel power fluctuations resulting from input power variation at the TDFA. The investigated system consists of 12 channels with -4 dBm total input power. Simulation results indicate that approximately1.5dB power excursion is produced after dropping 11 channels in unclamped-gain amplifier, and only 0.005 dB in a clamped-gain amplifier. Additionally, a clamped configuration brings the power excursion from 4.2 dB to under 0.08 dB, after adding 11 channels to the investigated system. Hence, optical gainclamping is a simple and robust technique for controlling the power transient in amplifiers at 2 μm.

  10. Assessment of the suitability of public mobile data networks for aircraft telemetry and control purposes

    NASA Astrophysics Data System (ADS)

    Gonzalez, F.; Walker, R.; Rutherford, N.; Turner, C.

    2011-04-01

    This paper provides a review of the state of the art of relevant work on the use of public mobile data networks for aircraft telemetry and control proposes. Moreover, it describes the characterisation for airborne uses of the public mobile data communication systems known broadly as 3G. The motivation for this study was to explore how this mature public communication systems could be used for aviation purposes. An experimental system was fitted to a light aircraft to record communication latency, line speed, RF level, packet loss and cell tower identifier. Communications was established using internet protocols and connection was made to a local server. The aircraft was flown in both remote and populous areas at altitudes up to 8500 ft in a region located in South East Queensland, Australia. Results show that the average airborne RF levels are better than those on the ground by 21% and in the order of -77 dbm. Latencies were in the order of 500 ms (1/2 the latency of Iridium), an average download speed of 0.48 Mb/s, average uplink speed of 0.85 Mb/s, a packet of information loss of 6.5%. The maximum communication range was also observed to be 70 km from a single cell station. The paper also describes possible limitations and utility of using such communications architecture for both manned and unmanned aircraft systems.

  11. Quantifying cobalt in doping control urine samples--a pilot study.

    PubMed

    Krug, Oliver; Kutscher, Daniel; Piper, Thomas; Geyer, Hans; Schänzer, Wilhelm; Thevis, Mario

    2014-01-01

    Since first reports on the impact of metals such as manganese and cobalt on erythropoiesis were published in the late 1920s, cobaltous chloride became a viable though not widespread means for the treatment of anaemic conditions. Today, its use is de facto eliminated from clinical practice; however, its (mis)use in human as well as animal sport as an erythropoiesis-stimulating agent has been discussed frequently. In order to assess possible analytical options and to provide relevant information on the prevalence of cobalt use/misuse among athletes, urinary cobalt concentrations were determined by inductively coupled plasma-mass spectrometry (ICP-MS) from four groups of subjects. The cohorts consisted of (1) a reference population with specimens of 100 non-elite athletes (not being part of the doping control system), (2) a total of 96 doping control samples from endurance sport athletes, (3) elimination study urine samples collected from six individuals having ingested cobaltous chloride (500 µg/day) through dietary supplements, and (4) samples from people supplementing vitamin B12 (cobalamin) at 500 µg/day, accounting for approximately 22 µg of cobalt. The obtained results demonstrated that urinary cobalt concentrations of the reference population as well as the group of elite athletes were within normal ranges (0.1-2.2 ng/mL). A modest but significant difference between these two groups was observed (Wilcoxon rank sum test, p < 0.01) with the athletes' samples presenting slightly higher urinary cobalt levels. The elimination study urine specimens yielded cobalt concentrations between 40 and 318 ng/mL during the first 6 h post-administration, and levels remained elevated (>22 ng/mL) up to 33 h. Oral supplementation of 500 µg of cobalamin did not result in urinary cobalt concentrations > 2 ng/mL. Based on these pilot study data it is concluded that measuring the urinary concentration of cobalt can provide information indicating the use

  12. Control of ferromagnetism in (In{sub 0.9}Fe{sub 0.1}){sub 2}O{sub 3} via F doping of electron carriers

    SciTech Connect

    Yan, Shiming Ou, Haifeng; Zhang, Liying; He, Jie; Yu, Jingxin

    2015-01-15

    Highlights: • F doping was achieved by a process of low temperature reaction with PVDF. • RTFM was obtained in the F-doped (In{sub 0.9}Fe{sub 0.1}){sub 2}O{sub 3.} • Magnetism and electric resistivity can be controlled by the content of doped F. • The FM can be ascribed to a long range exchange interaction induced by carriers. - Abstract: Ferromagnetism in (In{sub 0.9}Fe{sub 0.1}){sub 2}O{sub 3} was obtained by fluorine (F) doping. The ferromagnetism can be controlled by changing the electron carrier concentration via F doping. With increasing the F concentration, the electron carrier concentration increases, and samples undergo a paramagnetic insulator to ferromagnetic metal transition. For the ferromagnetic samples, the anomalous Hall effect (AHE) was observed. These results indicate that electron carriers play an important role in inducing the ferromagnetism.

  13. Controllable synthesis of Cu-doped CoO hierarchical structure for high performance lithium-ion battery

    NASA Astrophysics Data System (ADS)

    Chen, Chengcheng; Huang, Yanan; Zhang, Hao; Wang, Xiaofeng; Wang, Yijing; Jiao, Lifang; Yuan, Huatang

    2016-05-01

    We report on the strategy of Cu doping inducing the nanosize effect of CoO and their application as anode for lithium ion batteries. With an increase of Cu-doped amount, the structures and morphologies of CoO have special changes. The 0.05 mol Cu-doped CoO shows straw-like bundle structure assembled by nanorods, and the nanorods consist of ultra small nanoparticles (about 6-8 nm). Meanwhile, it shows an excellent rates performance and cycle life. The capacity of 800 mA h g-1 is obtained at 0.5 C after 80 cycles. The highest discharge capacity is 580 mA h g-1 at 10 C and the discharge capacities are relatively stable for 1000 cycles as an anode for Li-ion battery. Therefore, the controllable Cu-doped CoO composite could be deemed to be a potential candidate as an anode material.

  14. Controlled fabrication and tunable photoluminescence properties of Mn{sup 2+} doped graphene–ZnO composite

    SciTech Connect

    Luan, Xinglong; Zhang, Yihe Tong, Wangshu; Shang, Jiwu; An, Qi; Huang, Hongwei

    2014-11-15

    Highlights: • Graphene–ZnO composites were synthesized by a mixed solvothermal method. • ZnO quantum dots are distributed uniformly on the graphene sheets. • A possible hypothesis is raised for the influence of graphene oxide on the nucleation of ZnO. • Mn{sup 2+} doped graphene–ZnO composites were fabricated and the emission spectra can be tuned by doping. - Abstract: Graphene–ZnO composites (G–ZnO) with controlled morphology and photoluminescence property were synthesized by a mixed solvothermal method. Mixed solvent were composed by dimethyl sulfoxide and ethylene glycol. Fourier transform infrared spectroscopy, transmission electron microscopy and photoluminescence spectra were used to characterize G–ZnO. Graphene as a substrate can help the distribution and the dispersity of ZnO, and a possible model of the interaction between graphene oxide and ZnO particles is proposed. At the same time, graphene also reduce the size of ZnO particles to about 5 nm. Furthermore, Mn{sup 2+} ions dopes G–ZnO successfully by the mixed solvothermal synthesis and the doping of Mn{sup 2+} makes G–ZnO shift red from 465 nm to 548 nm and 554 nm in the emission spectrum. The changes of the emission spectrum by the adding of Mn{sup 2+} make G–ZnO have tunable photoluminescence spectrum which is desirable for practical applications.

  15. Control of selforganized magnetic nanocrystals aggregation in (Ga,Fe)N by co-doping with shallow donors and acceptors

    NASA Astrophysics Data System (ADS)

    Bonanni, A.; Navarro-Quezada, A.; Li, T.; Kiecana, M.; Sawicki, M.; Dietl, T.

    2008-03-01

    A number of possible room temperature functionalities has recently been proposed for magnetically doped semiconductors, in which spinodal decomposition leads to the self-organized formation of coherent ferromagnetic nanodots or nanocolumns [1]. It has also been suggested that the decomposition can be controlled in a wide range by growth conditions and co-doping [2]. We have extended our previous structural and magnetic studies of (Ga,Fe)N [3] by examining the effects of Si and Mg co-doping. As before, we have found the magnetic response to consist of a paramagnetic signal from substitutional Fe and of a ferromagnetic component due to Fe1-xN nanocrystals. Our results demonstrate that the co-doping reduces the fractional concentration of Fe contributing to the nanocrystals. This shows that tuning of the Fermi energy by changing the charge state of the transition metal ions affects their aggregation, as proposed recently [2].1. H.Katayama-Yosida et al., phys.stat. sol. (a) 204, 15 (2007); T.Dietl, arXiv:0711.0343. 2. S.Kuroda et al., Nature Mat. 6, 440 (2007). 3. A.Bonanni et al., Phys. Rev. B 75, 125210 (2007).

  16. The Nature and Purpose of the DBA: A Case for Clarity and Quality Control

    ERIC Educational Resources Information Center

    Sarros, James C.; Willis, Robert J.; Palmer, Gill

    2005-01-01

    Purpose--To explore the nature component parts, degree structure and purpose intended outcomes of the Doctor of Business Administration DBA degree, identifying the strengths and weaknesses of the degree as they stand presently, using Australian experience. Design/methodology/approach?-A review of DBA programme offerings in Australia identified…

  17. Morphology control of nanostructures: Na-doped PbTe-PbS system.

    PubMed

    He, Jiaqing; Blum, I D; Wang, Hui-Qiong; Girard, S N; Doak, J; Zhao, Li-Dong; Zheng, Jin-Cheng; Casillas, G; Wolverton, C; Jose-Yacaman, M; Seidman, D N; Kanatzidis, M G; Dravid, V P

    2012-11-14

    The morphology of crystalline precipitates in a solid-state matrix is governed by complex but tractable energetic considerations driven largely by volume strain energy minimization and anisotropy of interfacial energies. Spherical precipitate morphologies are favored by isotropic systems, while anisotropic interfacial energies give energetic preference to certain crystallographically oriented interfaces, resulting in a faceted precipitate morphology. In conventional solid-solution precipitation, a precipitate's morphological evolution is mediated by surface anchoring of capping molecules, which dramatically alter the surface energy in an anisotropic manner, thereby providing exquisite morphology control during crystal growth. Herein, we present experimental evidence and theoretical validation for the role of a ternary element (Na) in controlling the morphology of nanoscale PbS crystals nucleating in a PbTe matrix, an important bulk thermoelectric system. The PbS nanostructures formed by phase separation from a PbI(2)-doped or undoped PbTe matrix have irregular morphologies. However, replacing the iodine dopant with Na (1-2 mol %) alters dramatically the morphology of the PbS precipitates. Segregation of Na at PbTe/PbS interfaces result in cuboidal and truncated cuboidal morphologies for PbS. Using analytical scanning/transmission electron microscopy and atom-probe tomography, we demonstrate unambiguously that Na partitions to the precipitates and segregates at the matrix/precipitate interfaces, inducing morphological anisotropy of PbS precipitates. First-principles and semiclassical calculations reveal that Na as a solute in PbTe has a higher energy than in PbS and that Na segregation at a (100) PbTe/PbS interface decreases the total energy of matrix/precipitate system, resulting in faceting of PbS precipitates. These results provide an impetus for a new strategy for controlling morphological evolution in matrix/precipitate systems, mediated by solute partitioning

  18. Tailored formation of N-doped nanoarchitectures by diffusion-controlled on-surface (cyclo)dehydrogenation of heteroaromatics.

    PubMed

    Pinardi, Anna Lisa; Otero-Irurueta, Gonzalo; Palacio, Irene; Martinez, Jose Ignacio; Sanchez-Sanchez, Carlos; Tello, Marta; Rogero, Celia; Cossaro, Albano; Preobrajenski, Alexei; Gómez-Lor, Berta; Jancarik, Andrej; Stará, Irena G; Starý, Ivo; Lopez, M Francisca; Méndez, Javier; Martin-Gago, Jose Angel

    2013-04-23

    Surface-assisted cyclodehydrogenation and dehydrogenative polymerization of polycyclic (hetero)aromatic hydrocarbons (PAH) are among the most important strategies for bottom-up assembly of new nanostructures from their molecular building blocks. Although diverse compounds have been formed in recent years using this methodology, a limited knowledge on the molecular machinery operating at the nanoscale has prevented a rational control of the reaction outcome. We show that the strength of the PAH-substrate interaction rules the competitive reaction pathways (cyclodehydrogenation versus dehydrogenative polymerization). By controlling the diffusion of N-heteroaromatic precursors, the on-surface dehydrogenation can lead to monomolecular triazafullerenes and diazahexabenzocoronenes (N-doped nanographene), to N-doped oligomeric or polymeric networks, or to carbonaceous monolayers. Governing the on-surface dehydrogenation process is a step forward toward the tailored fabrication of molecular 2D nanoarchitectures distinct from graphene and exhibiting new properties of fundamental and technological interest. PMID:23506342

  19. Electric-field strength and doping level controlled spin-valley transport in a silicene np junction

    NASA Astrophysics Data System (ADS)

    Hua, Tao; Zhai, Xuechao; Yang, Zhihong; Wang, Shendong; Li, Bin

    2016-10-01

    The performance of np junction, as the basic unit of electronic devices, often determines the prospect of a material. We here investigate the spin- and valley-polarized transport in a silicene np junction, where a ferromagnetic field and a perpendicular electric field are applied in the p-doped region. It is found that pure spin current with valley polarization can be obtained under the control of electric-field strength and doping level, arising from the specific dispersion with spin- and valley-polarizations. By tuning the electric field properly, one can even realize a controllable state that supports 100% spin- and valley-polarized transport. At fixed electric field, we also demonstrate that the ferromagnetic field can greatly affect the ratios of spin- and valley-polarizations. These findings suggest that silicene is a promising material for application in future spintronics and valleytronics devices.

  20. Doping controlled spin reorientation in dysprosium-samarium orthoferrite single crystals

    NASA Astrophysics Data System (ADS)

    Cao, Shixun; Zhao, Weiyao; Kang, Baojuan; Zhang, Jincang; Ren, Wei

    2015-03-01

    As one of the most important phase transitions, spin reorientation (SR) in rare earth transition metal oxides draws much attention of emerging materials technologies. The origin of SR is the competition between different spin configurations which possess different free energy. We report the control of spin reorientation (SR) transition in perovskite rare earth orthoferrite Dy1-xSmxFeO3, a whole family of single crystals grown by optical floating zone method from x =0 to 1. Temperature dependence of the magnetizations under zero-field-cooling (ZFC) and field-cooling (FC) processes are studied. We have found a remarkable linear change of SR transition temperature in Sm-rich samples for x>0.2, which covers an extremely wide temperature range including room temperature. The a-axis magnetization curves under FCC process bifurcate from and then jump down to that of warming process (ZFC and FCW curves) in single crystals when x =0.5-0.9, suggesting complicated 4f-3d electron interactions among Dy3+-Sm3+, Dy3+-Fe3+, and Sm3+-Fe3+ sublattices of diverse magnetic configurations for materials physics and design. The magnetic properties and the doping effect on SR transition temperature in these single crystals might be useful in the spintronics device application. This work is supported by the National Key Basic Research Program of China (Grant No. 2015CB921600), and the National Natural Science Foundation of China (NSFC, Nos. 51372149, 50932003, 11274222).

  1. Controlling the alignment of liquid crystals by nanoparticle-doped and UV-treated polyimide alignment films

    NASA Astrophysics Data System (ADS)

    Jeng, Shie-Chang; Hwang, Su-June; Chen, Tai-An; Liu, Han-Shiang; Chen, Mu-Zhe

    2012-03-01

    We have developed two approaches for controlling the pretilt angles of liquid crystal molecules by using conventional polyimide (PI) alignment materials either doping homogeneous PIs with Polyhedral Oligomeric Silsequioxanes (POSS) nanoparticles or treating homeotropic PIs with ultraviolet light. These techniques are very simple and are compatible with current methods familiar in the LCD industry. The characteristics of modified PI alignment films and their applications for photonic devices are demonstrated in this paper.

  2. Doping-controlled Coherent Electron-Phonon Coupling in Vanadium Dioxide

    SciTech Connect

    Appavoo, Kannatassen; Wang, Bin; Nag, Joyeeta; Sfeir, Matthew Y.; Pantelides, Sokrates T.; Haglund, Richard F.

    2015-05-10

    Broadband femtosecond transient spectroscopy and density functional calculations reveal that substitutional tungsten doping of a VO2 film changes the coherent phonon response compared to the undoped film due to altered electronic and structural dynamics.

  3. A Framework for a General Purpose Intelligent Control System for Particle Accelerators. Phase II Final Report

    SciTech Connect

    Dr. Robert Westervelt; Dr. William Klein; Dr. Michael Kroupa; Eric Olsson; Rick Rothrock

    1999-06-28

    Vista Control Systems, Inc. has developed a portable system for intelligent accelerator control. The design is general in scope and is thus configurable to a wide range of accelerator facilities and control problems. The control system employs a multi-layer organization in which knowledge-based decision making is used to dynamically configure lower level optimization and control algorithms.

  4. Controlled thermodynamics for tunable electron doping of graphene on Ir(111)

    NASA Astrophysics Data System (ADS)

    Struzzi, C.; Praveen, C. S.; Scardamaglia, M.; Verbitskiy, N. I.; Fedorov, A. V.; Weinl, M.; Schreck, M.; Grüneis, A.; Piccinin, S.; Fabris, S.; Petaccia, L.

    2016-08-01

    The electronic properties and surface structures of K-doped graphene supported on Ir(111) are characterized as a function of temperature and coverage by combining low-energy electron diffraction, angle-resolved photoemission spectroscopy, and density functional theory (DFT) calculations. Deposition of K on graphene at room temperature (RT) yields a stable (√ 3 ×√ 3 ) R30° surface structure having an intrinsic electron doping that shifts the graphene Dirac point by ED=1.30 eV below the Fermi level. Keeping the graphene substrate at 80 K during deposition generates instead a (2 ×2 ) phase, which is stable until full monolayer coverage. Further deposition of K followed by RT annealing develops a double-layer K-doped graphene that effectively doubles the K coverage and the related charge transfer, as well as maximizing the doping level (ED=1.61 eV ). The measured electron doping and the surface reconstructions are rationalized by DFT calculations. These indicate a large thermodynamic driving force for K intercalation below the graphene layer. The electron doping and Dirac point shifts calculated for the different structures are in agreement with the experimental measurements. In particular, the K4 s bands are shown to be sensitive to both the K intercalation and periodicity and are therefore suggested as a fingerprint for the location and ordering of the K dopants.

  5. Three-dimensional endothelial cell morphogenesis under controlled ion release from copper-doped phosphate glass.

    PubMed

    Stähli, Christoph; James-Bhasin, Mark; Nazhat, Showan N

    2015-02-28

    Copper ions represent a promising angiogenic agent but are associated with cytotoxicity at elevated concentrations. Phosphate-based glasses (PGs) exhibit adjustable dissolution properties and allow for controlled ion release. This study examined the formation of capillary-like networks by SVEC4-10 endothelial cells (ECs) seeded in a three-dimensional (3D) type I collagen hydrogel matrix mixed with PG particles of the formulation 50P2O5-30CaO-(20-x)Na2O-xCuO (x=0 and 10 mol%). Copper and total phosphorus release decreased over time and was more sustained in the case of 10% CuO PG. Moreover, increasing the concentration of 10% CuO PG in collagen substantially delayed dissolution along with preferential release of copper. A 3D morphometric characterization method based on confocal laser scanning microscopy image stacks was developed in order to quantify EC network length, connectivity and branching. Network length was initially reduced in a concentration-dependent fashion by 10% CuO PG and, to a lesser extent, by 0% CuO PG, but reached values identical to the non-PG control by day 5 in culture. This reduction was attributed to a PG-mediated decrease in cell metabolic activity while cell proliferation as well as network connectivity and branching were independent of PG content. Gene expression of matrix metalloproteinases (MMP)-1 and -2 was up-regulated by PGs, indicating that MMPs did not play a critical role in network growth. The relationship between ion release and EC morphogenesis in 3D provided in this study is expected to contribute to an ultimately successful pro-angiogenic application of CuO-doped PGs. PMID:25575746

  6. Lanthanide-doped Sr2YF7 nanoparticles: controlled synthesis, optical spectroscopy and biodetection

    NASA Astrophysics Data System (ADS)

    Yang, Yuhan; Tu, Datao; Zheng, Wei; Liu, Yongsheng; Huang, Ping; Ma, En; Li, Renfu; Chen, Xueyuan

    2014-09-01

    Sr2YF7, as an important matrix for trivalent lanthanide (Ln3+) ions to fabricate upconversion (UC) or downshifting (DS) phosphors, has been rarely reported. Herein, monodisperse and size-controllable tetragonal-phase Ln3+-doped Sr2YF7 nanoparticles (NPs) were synthesized via a facile thermal decomposition method. Upon excitation at 980 nm, UC luminescence properties of Sr2YF7:Ln3+/Yb3+ (Ln = Tm, Er) NPs were systematically surveyed. Particularly, after coating an inert Sr2YF7 shell, the UC luminescence intensities of Sr2YF7:Tm3+/Yb3+ and Sr2YF7:Er3+/Yb3+ NPs were enhanced by ~22 and 4 times, respectively. Furthermore, intense multicolor DS luminescence was also achieved in Ce3+/Tb3+ or Eu3+ doped Sr2YF7 NPs, with absolute quantum yields of 55.1% (Tb3+) and 11.2% (Eu3+). The luminescence lifetimes of 5D4 (Tb3+) and 5D0 (Eu3+) were determined to be 3.7 and 8.1 ms, respectively. By utilizing the long-lived luminescence of Ln3+ in these Sr2YF7 NPs, we demonstrated their application as sensitive heterogeneous time-resolved photoluminescence bioprobes to detect the protein of avidin and the tumor marker of the carcinoembryonic antigen (CEA) with their limits of detection down to 40.6 and 94.9 pM, and thus reveal the great potential of these Sr2YF7:Ln3+ nanoprobes in cancer diagnosis.Sr2YF7, as an important matrix for trivalent lanthanide (Ln3+) ions to fabricate upconversion (UC) or downshifting (DS) phosphors, has been rarely reported. Herein, monodisperse and size-controllable tetragonal-phase Ln3+-doped Sr2YF7 nanoparticles (NPs) were synthesized via a facile thermal decomposition method. Upon excitation at 980 nm, UC luminescence properties of Sr2YF7:Ln3+/Yb3+ (Ln = Tm, Er) NPs were systematically surveyed. Particularly, after coating an inert Sr2YF7 shell, the UC luminescence intensities of Sr2YF7:Tm3+/Yb3+ and Sr2YF7:Er3+/Yb3+ NPs were enhanced by ~22 and 4 times, respectively. Furthermore, intense multicolor DS luminescence was also achieved in Ce3+/Tb3+ or Eu3

  7. Bi-Sn alloy catalyst for simultaneous morphology and doping control of silicon nanowires in radial junction solar cells

    SciTech Connect

    Yu, Zhongwei; Lu, Jiawen; Qian, Shengyi; Xu, Jun; Xu, Ling; Wang, Junzhuan; Shi, Yi; Chen, Kunji; Yu, Linwei E-mail: linwei.yu@polytechnique.edu

    2015-10-19

    Low-melting point metals such as bismuth (Bi) and tin (Sn) are ideal choices for mediating a low temperature growth of silicon nanowires (SiNWs) for radial junction thin film solar cells. The incorporation of Bi catalyst atoms leads to sufficient n-type doping in the SiNWs core that exempts the use of hazardous dopant gases, while an easy morphology control with pure Bi catalyst has never been demonstrated so far. We here propose a Bi-Sn alloy catalyst strategy to achieve both a beneficial catalyst-doping and an ideal SiNW morphology control. In addition to a potential of further growth temperature reduction, we show that the alloy catalyst can remain quite stable during a vapor-liquid-solid growth, while providing still sufficient n-type catalyst-doping to the SiNWs. Radial junction solar cells constructed over the alloy-catalyzed SiNWs have demonstrated a strongly enhanced photocurrent generation, thanks to optimized nanowire morphology, and largely improved performance compared to the reference samples based on the pure Bi or Sn-catalyzed SiNWs.

  8. Bi-Sn alloy catalyst for simultaneous morphology and doping control of silicon nanowires in radial junction solar cells

    NASA Astrophysics Data System (ADS)

    Yu, Zhongwei; Lu, Jiawen; Qian, Shengyi; Misra, Soumyadeep; Yu, Linwei; Xu, Jun; Xu, Ling; Wang, Junzhuan; Shi, Yi; Chen, Kunji; Roca i Cabarrocas, Pere

    2015-10-01

    Low-melting point metals such as bismuth (Bi) and tin (Sn) are ideal choices for mediating a low temperature growth of silicon nanowires (SiNWs) for radial junction thin film solar cells. The incorporation of Bi catalyst atoms leads to sufficient n-type doping in the SiNWs core that exempts the use of hazardous dopant gases, while an easy morphology control with pure Bi catalyst has never been demonstrated so far. We here propose a Bi-Sn alloy catalyst strategy to achieve both a beneficial catalyst-doping and an ideal SiNW morphology control. In addition to a potential of further growth temperature reduction, we show that the alloy catalyst can remain quite stable during a vapor-liquid-solid growth, while providing still sufficient n-type catalyst-doping to the SiNWs. Radial junction solar cells constructed over the alloy-catalyzed SiNWs have demonstrated a strongly enhanced photocurrent generation, thanks to optimized nanowire morphology, and largely improved performance compared to the reference samples based on the pure Bi or Sn-catalyzed SiNWs.

  9. Enhanced electrical conductivities of N-doped carbon nanotubes by controlled heat treatment.

    PubMed

    Fujisawa, Kazunori; Tojo, Tomohiro; Muramatsu, Hiroyuki; Elías, Ana L; Vega-Díaz, Sofía M; Tristán-López, Ferdinando; Kim, Jin Hee; Hayashi, Takuya; Kim, Yoong Ahm; Endo, Morinobu; Terrones, Mauricio

    2011-10-01

    The thermal stability of nitrogen (N) functionalities on the sidewalls of N-doped multi-walled carbon nanotubes was investigated at temperatures ranging between 1000 °C and 2000 °C. The structural stability of the doped tubes was then correlated with the electrical conductivity both at the bulk and at the individual tube levels. When as-grown tubes were thermally treated at 1000 °C, we observed a very significant decrease in the electrical resistance of the individual nanotubes, from 54 kΩ to 0.5 kΩ, which is attributed to a low N doping level (e.g. 0.78 at% N). We noted that pyridine-type N was first decomposed whereas the substitutional N was stable up to 1500 °C. For nanotubes heat treated to 1800 °C and 2000 °C, the tubes exhibited an improved degree of crystallinity which was confirmed by both the low R value (I(D)/I(G)) in the Raman spectra and the presence of straight graphitic planes observed in TEM images. However, N atoms were not detected in these tubes and caused an increase in their electrical resistivity and resistance. These partially annealed doped tubes with enhanced electrical conductivities could be used in the fabrication of robust and electrically conducting composites, and these results could be extrapolated to N-doped graphene and other nanocarbons.

  10. Control over the performance characteristics of a passively mode-locked erbium-doped fibre ring laser

    SciTech Connect

    Chernysheva, M A; Krylov, A A; Dianov, E M; Ogleznev, A A; Arutyunyan, N R; Pozharov, A S; Obraztsova, E D

    2013-08-31

    We report an all-fibre ultrashort pulse erbium-doped ring laser passively mode-locked by single-wall carbon nanotubes dispersed in carboxymethylcellulose-based polymer films. Owing to intracavity dispersion management and controlled absorption in the polymer films, the laser is capable of generating both femto- and picosecond pulses of various shapes in the spectral range 1.53 – 1.56 μm. We have demonstrated and investigated the generation of almost transform- limited, inversely modified solitons at a high normal cavity dispersion. (control of laser radiation parameters)

  11. Controlling sources of preanalytical variability in doping samples: challenges and solutions.

    PubMed

    Lippi, Giuseppe; Mattiuzzi, Camilla; Banfi, Giuseppe

    2013-06-01

    The use of illicit substances and methods contravenes the ethics of sports and may be associated with side effects. Antidoping testing is an essential tool for preventing or limiting the consequences of cheating in sports. As for conventional laboratory testing, major emphasis has been placed on analytical quality, overlooking the inherent risks that may arise from analysis of unsuitable doping samples. The adherence to scrupulous criteria for collection, handling, transportation and storage of samples, especially blood and urine samples, is essential. The leading preanalytical variables that influence doping sample quality include biological variability, sample collection, venous stasis, spurious hemolysis and presence of other interfering substances, sample manipulation and degradation, and inappropriate conditions for transportation and storage. This article provides a personal overview about the current challenges in preanalytical management of doping samples, as well as potential solutions for preventing the negative impact of preanalytical variables on sample quality and test results. PMID:23795934

  12. Controlling sources of preanalytical variability in doping samples: challenges and solutions.

    PubMed

    Lippi, Giuseppe; Mattiuzzi, Camilla; Banfi, Giuseppe

    2013-06-01

    The use of illicit substances and methods contravenes the ethics of sports and may be associated with side effects. Antidoping testing is an essential tool for preventing or limiting the consequences of cheating in sports. As for conventional laboratory testing, major emphasis has been placed on analytical quality, overlooking the inherent risks that may arise from analysis of unsuitable doping samples. The adherence to scrupulous criteria for collection, handling, transportation and storage of samples, especially blood and urine samples, is essential. The leading preanalytical variables that influence doping sample quality include biological variability, sample collection, venous stasis, spurious hemolysis and presence of other interfering substances, sample manipulation and degradation, and inappropriate conditions for transportation and storage. This article provides a personal overview about the current challenges in preanalytical management of doping samples, as well as potential solutions for preventing the negative impact of preanalytical variables on sample quality and test results.

  13. Fermi energy tuning with light to control doping profiles during epitaxy

    SciTech Connect

    Sanders, C. E.; Beaton, D. A.; Reedy, R. C.; Alberi, K.

    2015-05-04

    The influence of light stimulation and photogenerated carriers on the process of dopant surface segregation during growth is studied in molecular beam epitaxially grown Si-doped GaAs structures. The magnitude of surface segregation decreases under illumination by above-bandgap photons, wherein splitting of the quasi Fermi levels reduces the band bending at the growth surface and raises the formation energy of compensating defects that can enhance atomic diffusion. We further show that light-stimulated epitaxy can be used as a practical approach to diminish dopant carry-forward in device structures and improve the performance of inverted modulation-doped quantum wells.

  14. Collapse and control of the MnAu2 spin-spiral state through pressure and doping

    NASA Astrophysics Data System (ADS)

    Glasbrenner, J. K.

    2016-05-01

    MnAu2 is a spin-spiral material with in-plane ferromagnetic Mn layers that form a screw-type pattern around a tetragonal c axis. The spiral angle θ was shown using neutron diffraction experiments to decrease with pressure, and in later studies it was found to suffer a collapse to a ferromagnetic state above a critical pressure, although the two separate experiments did not agree on whether this phase transition is first or second order. To resolve this contradiction, we use density functional theory calculations to investigate the spiral state as a function of pressure, charge doping, and also electronic correlations via a Hubbard-like U . We fit the results to the one-dimensional J1-J2-J3-J4 Heisenberg model, which predicts either a first- or second-order spiral-to-ferromagnetic phase transition for different regions of parameter space. At ambient pressure, MnAu2 sits close in parameter space to a dividing line separating first- and second-order transitions, and a combination of pressure and electron doping shifts the system from the first-order region into the second-order region. Our findings demonstrate that the contradiction in pressure experiments regarding the kind of phase transition are likely due to variations in sample quality. Our results also suggest that MnAu2 is amenable to engineering via chemical doping and to controlling θ using pressure and gate voltages, which holds potential for integration in spintronic devices.

  15. All-solid very large mode area ytterbium-doped silica microstructured fiber based on accurate control on cladding index.

    PubMed

    Wei, Huifeng; Chen, Kangkang; Yang, Yucheng; Li, Jinyan

    2016-04-18

    We have demonstrated a new approach for developing very large mode area silica-based microstructured Ytterbium (Yb)-doped fibers. The microstructured region acting as pump cladding around the core is composed by periodically arranged low-index Fluorine-doped silica inclusions with an extremely low filling ratio of 0.088. To the best of our knowledge, we achieved the most accurate controlling on cladding index by 1 × 10-5 via our passively doped cladding (PDC) method. Two fibers with 127μm and 50μm core diameter respectively were fabricated from the same final preform designed by this approach. It is verified that our 50μm core diameter fiber can maintain robust single mode behavior at 1064nm wavelength. The advantage of an all-solid structure along with a much simpler fabrication process makes our approach very suitable for realizing very large mode area fibers for high power fiber laser application. PMID:27137328

  16. Control of the multiferroic transition in Ni3V2O8 by transition metal doping

    NASA Astrophysics Data System (ADS)

    Kumarasiri, A.; Lawes, G.

    2011-08-01

    We have studied the effects of doping magnetic ions on the phase transitions in polycrystalline Ni3V2O8 samples using magnetic, dielectric, and specific heat measurements. Substituting spin-1/2 Cu results in a larger suppression of the transition temperatures than observed on doping with spin-3/2 Co. The multiferroic-ordering transition persists at small concentrations for both Co and Cu dopants, with this phase still developing at concentrations of almost 30 at% Co. However, the multiferroic-magnetic structure is completely suppressed at only 10 at% Cu. On the Co-rich side of the composition, we find that the magnetic-ordering temperatures for Co3V2O8 are suppressed rapidly with Ni doping. We present phase diagrams for (Ni1-xMx)3V2O8 (M = Cu and Co). These studies suggest that the spin structures in Ni3V2O8 responsible for the development of ferroelectric order are relatively robust against perturbations produced by magnetic dopants, with the most significant disruption of the magnetic structure developing for Cu doping.

  17. "Pictures with a purpose": the birth control debate on the big screen.

    PubMed

    Parry, Manon

    2011-01-01

    In the first half of the twentieth century, birth control advocates used the mass media to reframe contraception from a private, secret matter to an acceptable part of life fit for public discussion. Although their campaign began in print, they quickly embraced the more far-reaching medium of film to deliver their message. This article argues that birth control advocates circumvented the Comstock Act in the early decades of the twentieth century by taking up this new medium as part of a long-running strategy to publicize the birth control movement. Their efforts shaped both the public debate on the topic and the development of motion picture censorship. PMID:22250312

  18. "Pictures with a purpose": the birth control debate on the big screen.

    PubMed

    Parry, Manon

    2011-01-01

    In the first half of the twentieth century, birth control advocates used the mass media to reframe contraception from a private, secret matter to an acceptable part of life fit for public discussion. Although their campaign began in print, they quickly embraced the more far-reaching medium of film to deliver their message. This article argues that birth control advocates circumvented the Comstock Act in the early decades of the twentieth century by taking up this new medium as part of a long-running strategy to publicize the birth control movement. Their efforts shaped both the public debate on the topic and the development of motion picture censorship.

  19. Controlling levonorgestrel binding and release in a multi-purpose prevention technology vaginal ring device.

    PubMed

    Murphy, Diarmaid J; Boyd, Peter; McCoy, Clare F; Kumar, Sandeep; Holt, Jonathon D S; Blanda, Wendy; Brimer, Andrew N; Malcolm, R Karl

    2016-03-28

    Despite a long history of incorporating steroids into silicone elastomers for drug delivery applications, little is presently known about the propensity for irreversible drug binding in these systems. In this study, the ability of the contraceptive progestin levonorgestrel to bind chemically with hydrosilane groups in addition-cure silicone elastomers has been thoroughly investigated. Cure time, cure temperature, levonorgestrel particle size, initial levonorgestrel loading and silicone elastomer type were demonstrated to be key parameters impacting the extent of levonorgestrel binding, each through their influence on the solubility of levonorgestrel in the silicone elastomer. Understanding and overcoming this levonorgestrel binding phenomenon is critical for the ongoing development of a number of drug delivery products, including a multi-purpose technology vaginal ring device offering simultaneous release of levonorgestrel and dapivirine - a lead candidate antiretroviral microbicide - for combination HIV prevention and hormonal contraception.

  20. Osteoblastic differentiation under controlled bioactive ion release by silica and titania doped sodium-free calcium phosphate-based glass.

    PubMed

    Shah Mohammadi, Maziar; Chicatun, Florencia; Stähli, Christoph; Muja, Naser; Bureau, Martin N; Nazhat, Showan N

    2014-09-01

    Sodium-free phosphate-based glasses (PGs) doped with both SiO2 and TiO2 (50P2O5-40CaO-xSiO2-(10-x)TiO2, where x=10, 7, 5, 3, and 0mol%) were developed and characterised for controlled ion release applications in bone tissue engineering. Substituting SiO2 with TiO2 directly increased PG density and glass transition temperature, indicating a cross-linking effect of Ti on the glass network which was reflected by significantly reduced degradation rates in an aqueous environment. X-ray diffraction confirmed the presence of Ti(P2O7) in crystallised TiO2-containing PGs, and nuclear magnetic resonance showed an increase in Q(1) phosphate species with increasing TiO2 content. Substitution of SiO2 with TiO2 also reduced hydrophilicity and surface energy. In biological assays, MC3T3-E1 pre-osteoblasts effectively adhered to the surface of PG discs and the incorporation of TiO2, and hence higher stability of the PG network, significantly increased cell viability and metabolic activity indicating the biocompatibility of the PGs. Addition of SiO2 increased ionic release from the PG, which stimulated alkaline phosphatase (ALP) activity in MC3T3-E1 cells upon ion exposure. The incorporation of 3mol% TiO2 was required to stabilise the PG network against unfavourable rapid degradation in aqueous environments. However, ALP activity was greatest in PGs doped with 5-7mol% SiO2 due to up-regulation of ionic concentrations. Thus, the properties of PGs can be readily controlled by modifying the extent of Si and Ti doping in order to optimise ion release and osteoblastic differentiation for bone tissue engineering applications. PMID:24945606

  1. Color-control of the persistent luminescence of cadmium silicate doped with transition metals

    SciTech Connect

    Abreu, Carolina M.; Silva, Ronaldo S.; Valerio, Mário E.G.; Macedo, Zélia S.

    2013-04-15

    The structural and optical characterization of cadmium silicate (CdSiO{sub 3}) doped with transition metals is reported. This crystalline system presents intrinsic luminescence and is usually studied as host matrix for rare earth ions. In this work, CdSiO{sub 3} was doped with Mn, Ni and Cr to produce multicolored luminescent materials. Single crystalline CdSiO{sub 3} was obtained via solid state synthesis at 1000 °C/8 h. The valence of the dopants inserted in the host matrix was determined via XANES as 3+ for Cr, 2+ for Ni and both 2+ and 3+ for Mn, according to XANES studies. The optical absorption spectra of the samples presented wide bands in the visible region that were associated with the internal transitions of the dopants. All the samples presented photoluminescent bands near 420 nm, 496 nm and 591 nm, with different relative intensities that yield characteristic luminescence colors ranging from blue to red. - Graphical abstract: Phosphorescence of cadmium silicate doped with transition metals: nature of defects and possible luminescent channels. Highlights: ► CdSiO{sub 3} was doped with Mn, Ni and Cr to produce multicolored phosphors. ► Valence of the dopants was determined as 3+ for Cr, 2+ for Ni and 2+ and 3+ for Mn. ► The presence of absorption bands in the visible region led to self-absorption. ► Self-absorption in some cases can decrease the light output. ► Luminescent channels were created and related to internal transitions of the dopants.

  2. Infrared thermography for process control and predictive maintenance purposes in a steel wire drawing machine

    NASA Astrophysics Data System (ADS)

    Rozlosnik, Andres E.; Lardone, Victor M.

    1999-03-01

    The industrial drawing process reduces the section of the wire rod by pulling the material through a hard die. This process generates heat by deformation and friction. The heat generated must be immediately removed after every reduction diameter step, otherwise the final quality of wire and the drawing performance will be poor. That is the reason why the improvement of the cooling efficiency in the drawing machine is of great importance. The better the cooling efficiency, the greater the wire quality and the productivity of the process will be. Nowadays, the infrared thermography control offer the possibility to analyze how the drawing aspect is affecting the cooling efficiency and how this technique allows the drawing process improvements. As you look at the capstans in the wire process control, you are doing at the same time, predictive maintenance in the machine.

  3. Optical fibre techniques for use within tamper indicating enclosures designed for arms control verification purposes

    NASA Astrophysics Data System (ADS)

    Dyer, Thomas C.; Thompson, Alexander W. J.; Wynn, Paul; White, Helen

    2014-10-01

    Ensuring that a future nuclear arms control agreement can be verified is a complex technical challenge. Tamper Indicating Enclosures (TIEs) are likely to be deployed as part of a chain of custody regime, providing an indication of an unauthorised attempt to access an item within the agreement. This paper focuses on the assessment of optical fibre techniques for ensuring boundary control as part of a TIE design. The results of optical fibre damage, subsequent repair attempts, enclosure construction considerations and unique identification features have been evaluated for a selection of fused-silica optical fibres. This paper focuses on detecting a fibre repair attempt, presents a method for increasing repair resistance and a method for uniquely identifying an enclosure using the optical signature from the embedded optical fibre.

  4. Special purpose parallel computer architecture for real-time control and simulation in robotic applications

    NASA Technical Reports Server (NTRS)

    Fijany, Amir (Inventor); Bejczy, Antal K. (Inventor)

    1993-01-01

    This is a real-time robotic controller and simulator which is a MIMD-SIMD parallel architecture for interfacing with an external host computer and providing a high degree of parallelism in computations for robotic control and simulation. It includes a host processor for receiving instructions from the external host computer and for transmitting answers to the external host computer. There are a plurality of SIMD microprocessors, each SIMD processor being a SIMD parallel processor capable of exploiting fine grain parallelism and further being able to operate asynchronously to form a MIMD architecture. Each SIMD processor comprises a SIMD architecture capable of performing two matrix-vector operations in parallel while fully exploiting parallelism in each operation. There is a system bus connecting the host processor to the plurality of SIMD microprocessors and a common clock providing a continuous sequence of clock pulses. There is also a ring structure interconnecting the plurality of SIMD microprocessors and connected to the clock for providing the clock pulses to the SIMD microprocessors and for providing a path for the flow of data and instructions between the SIMD microprocessors. The host processor includes logic for controlling the RRCS by interpreting instructions sent by the external host computer, decomposing the instructions into a series of computations to be performed by the SIMD microprocessors, using the system bus to distribute associated data among the SIMD microprocessors, and initiating activity of the SIMD microprocessors to perform the computations on the data by procedure call.

  5. Paramagnetic behavior of Co doped TiO2 nanocrystals controlled by self-purification mechanism

    NASA Astrophysics Data System (ADS)

    Anitha, B.; Khadar, M. Abdul; Banerjee, Alok

    2016-07-01

    Doping in nanocrystals is a challenging process because of the self- purification mechanism which tends to segregate out the dopants resulting in a greater dopant concentration near the surface than at the interior of nanocrystals. In the present work nanocrystals of TiO2 doped with different atom % of Co were synthesized by peroxide gel method. XRD analysis confirmed the tetragonal anatase structure and HRTEM images showed the rod-like morphology of the samples. Raman modes of anatase phase of TiO2 along with weak intensity peaks of Co3O4 for higher Co dopant concentrations were observed for the samples. EPR measurements revealed the presence of cobalt in +2 oxidation state in the TiO2 matrix. SQUID measurements indicated paramagnetic behavior of the Co doped TiO2 nanocrystals. The paramagnetic behavior is attributed to an increased concentration of Co2+ ions and an increased presence of Co3O4 phase near the surface of the TiO2 nanocrystals due to self-purification mechanism.

  6. Sodium-Doped Molybdenum Targets for Controllable Sodium Incorporation in CIGS Solar Cells: Preprint

    SciTech Connect

    Mansfield, L. M.; Repins, I. L.; Glynn, S.; Carducci, M. D.; Honecker, D. M.; Pankow, J.; Young, M.; DeHart, C.; Sundaramoorthy, R.; Beall, C. L.; To, B.

    2011-07-01

    The efficiency of Cu(In,Ga)Se2 (CIGS) solar cells is enhanced when Na is incorporated in the CIGS absorber layer. This work examines Na incorporation in CIGS utilizing Na-doped Mo sputtered from targets made with sodium molybdate-doped (MONA) powder. Mo:Na films with varying thicknesses were sputtered onto Mo-coated borosilicate glass (BSG) or stainless steel substrates for CIGS solar cells. By use of this technique, the Na content of CIGS can be varied from near-zero to higher than that obtained from a soda-lime glass (SLG) substrate. Targets and deposition conditions are described. The doped Mo films are analyzed, and the resulting devices are compared to devices fabricated on Mo-coated SLG as well as Mo-coated BSG with NaF. Completed devices utilizing MONA exceeded 15.7% efficiency without anti-reflective coating, which was consistently higher than devices prepared with the NaF precursor. Strategies for minimizing adhesion difficulties are presented.

  7. Controlled p-type Sb doping in LPE-grown Hg1-x Cdx Te epilayers

    NASA Astrophysics Data System (ADS)

    Harman, Theodore C.

    1993-09-01

    A Te-rich liquid-phase-epitaxial growth process is reported whereby reproducible Sb-doped layers are prepared with hole concentrations and hole mobilities ranging from 1.8×1016 to 1.3×1019 cm-3 and 280 to 29 cm2/V s, respectively, at 77K for x-values ranging from 0.23 to 0.29. An effective electronic distribution coefficient for Sb of 0.01 is calculated from the hole concentration at 77K and the concentration of Sb in the growth solution. The process for group Va doping of low-x Hg1-x Cdx Te from Te-rich solutions and the procedure for the growth of a CdZnTe buffer layer on a CdTeSe substrate are described. For Te-rich Cd-Zn-Te growth solutions the distribution coefficient of Zn was found to be 18. The growth of a structure consisting of an Sb-doped HgCdTe epilayer on a CdZnTe buffer layer lattice matched (Δa/a<10-4) to a CdSeTe substrate has been demonstrated.

  8. Sodium-Doped Molybdenum Targets for Controllable Sodium Incorporation in CIGS Solar Cells

    SciTech Connect

    Mansfield, L. M.; Repins, I. L.; Glynn, S.; Carducci, M. D.; Honecker, D. M.; Pankow, J.l W.; Young, M. R.; DeHart, C.; Sundaramoorthy, R.; Beall, C. L.; To, B.

    2011-01-01

    The efficiency of Cu(In, Ga)Se{sub 2} (CIGS) solar cells is enhanced when Na is incorporated in the CIGS absorber layer. This work examines Na incorporation in CIGS utilizing Na-doped Mo sputtered from targets made with sodium molybdate-doped (MONA) powder. Mo:Na films with varying thicknesses were sputtered onto Mo-coated borosilicate glass (BSG) or stainless steel substrates for CIGS solar cells. By use of this technique, the Na content of CIGS can be varied from near-zero to higher than that obtained from a soda-lime glass (SLG) substrate. Targets and deposition conditions are described. The doped Mo films are analyzed, and the resulting devices are compared to devices fabricated on Mo-coated SLG as well as Mo-coated BSG with NaF. Completed devices utilizing MONA exceeded 15.7% efficiency without anti-reflective coating, which was consistently higher than devices prepared with the NaF precursor. Strategies for minimizing adhesion difficulties are presented.

  9. In Situ Control of Underwater-Pinning of Organic Droplets on a Surfactant-Doped Conjugated Polymer Surface.

    PubMed

    Xu, Wei; Xu, Jian; Choi, Chang-Hwan; Yang, Eui-Hyeok

    2015-11-25

    Controlling the pinning of organic droplets on solid surfaces is of fundamental and practical interest in the field of material science and engineering, which has numerous applications such as surface cleaning, water treatment, and microfluidics. Here, a rapid in situ control of pinning and actuation of organic droplets is demonstrated on dodecylbenzenesulfonate-doped polypyrrole (PPy(DBS)) surfaces in an aqueous environment via an electrochemical redox process. A dramatic change of the pinning results from the transport of DBS(-) molecules between the PPy(DBS) surface and the aqueous environment, as well as from a simultaneous alternation of the surface oleophobicity to organic liquids during the redox process. This in situ control of the droplet pinning enables a stop-and-go droplet actuation, applicable to both polar and apolar organic droplets, at low voltages (∼0.9 V) with an extremely low roll-off angle (∼0.4°). PMID:26536473

  10. Controlling the 1 μm spontaneous emission in Er/Yb co-doped fiber amplifiers.

    PubMed

    Sobon, Grzegorz; Kaczmarek, Pawel; Antonczak, Arkadiusz; Sotor, Jaroslaw; Abramski, Krzysztof M

    2011-09-26

    In this paper we present our experimental studies on controlling the amplified spontaneous emission (ASE) from Yb(3+) ions in Er/Yb co-doped fiber amplifiers. We propose a new method of controlling the Yb-ASE by stimulating a laser emission at 1064 nm in the amplifier, by providing a positive 1 μm signal feedback loop. The results are discussed and compared to a conventional amplifier setup without 1 μm ASE control and to an amplifier with auxiliary 1064 nm seeding. We have shown, that applying a 1064 nm signal loop in an Er/Yb amplifier can increase the output power at 1550 nm and provide stable operation without parasitic lasing at 1 μm.

  11. Doping control analysis of 46 polar drugs in horse plasma and urine using a 'dilute-and-shoot' ultra high performance liquid chromatography-high resolution mass spectrometry approach.

    PubMed

    Kwok, Wai Him; Choi, Timmy L S; Kwok, Karen Y; Chan, George H M; Wong, Jenny K Y; Wan, Terence S M

    2016-06-17

    The high sensitivity of ultra high performance liquid chromatography coupled with high resolution mass spectrometry (UHPLC-HRMS) allows the identification of many prohibited substances without pre-concentration, leading to the development of simple and fast 'dilute-and-shoot' methods for doping control for human and equine sports. While the detection of polar drugs in plasma and urine is difficult using liquid-liquid or solid-phase extraction as these substances are poorly extracted, the 'dilute-and-shoot' approach is plausible. This paper describes a 'dilute-and-shoot' UHPLC-HRMS screening method to detect 46 polar drugs in equine urine and plasma, including some angiotensin-converting enzyme (ACE) inhibitors, sympathomimetics, anti-epileptics, hemostatics, the new doping agent 5-aminoimidazole-4-carboxamide-1-β-d-ribofuranoside (AICAR), as well as two threshold substances, namely dimethyl sulfoxide and theobromine. For plasma, the sample (200μL) was protein precipitated using trichloroacetic acid, and the resulting supernatant was diluted using Buffer A with an overall dilution factor of 3. For urine, the sample (20μL) was simply diluted 50-fold with Buffer A. The diluted plasma or urine sample was then analysed using a UHPLC-HRMS system in full-scan ESI mode. The assay was validated for qualitative identification purpose. This straightforward and reliable approach carried out in combination with other screening procedures has increased the efficiency of doping control analysis in the laboratory. Moreover, since the UHPLC-HRMS data were acquired in full-scan mode, the method could theoretically accommodate an unlimited number of existing and new doping agents, and would allow a retrospectively search for drugs that have not been targeted at the time of analysis. PMID:27180888

  12. Screening for two selective androgen receptor modulators using gas chromatography-mass spectrometry in doping control analysis.

    PubMed

    Thevis, Mario; Kohler, Maxie; Schlörer, Nils; Fusshöller, Gregor; Schänzer, Wilhelm

    2008-01-01

    Selective androgen receptor modulators (SARMs) have become a major field of clinical research enabling the tissue-selective stimulation of androgen receptors. The treatment of debilitating diseases, osteoporosis and frailty are primary goals and promising results have been obtained from clinical trials. However, the potential for misuse of SARMs in sport is great and drug testing methods based on liquid chromatography were established for different classes including arylpropionamide-, 2-quinolinone- and bicyclic hydantoin-derived compounds. As gas chromatography and mass spectrometry (GC-MS) are still important analytical tools in sports drug testing, a method to determine 2-quinolinone- and bicyclic hydantoin-derived SARMs established. Spiked urine samples were subjected to routine doping control protocols including enzymatic hydrolysis, liquid-liquid extraction, concentration and derivatisation to trimethylsilylated analogues followed by GC-MS analysis. The method was validated for the items specificity, lower limit of detection (0.2-10 ng mL(-1)), recovery (83-85%), intraday and interday precision (9-15% and 13-18%, respectively), which demonstrates the suitability of conventional GC-MS systems to determine representatives of an emerging class of compounds in doping control specimens.

  13. Flood mitigation through optimal control of a network of multi-purpose reservoirs by using Model Predictive Control

    NASA Astrophysics Data System (ADS)

    MyoLin, Nay; Rutten, Martine; van de Giesen, Nick

    2016-04-01

    Flooding is a common natural disaster in the world. Construction of reservoirs, sluice gates, dikes, embankments and sea walls are implemented to minimize loss of life and property in a flood event. Rather than completely relying on large structural measures, non-structural measures such as real time control of a reservoir system can also improve flood prevention and water supply in a river basin. In this paper, we present the optimal operation of a multi-reservoir system by using Model Predictive Control (MPC) and particular attention is focused on flood mitigation of the Sittaung River Basin, Myanmar. The main challenges are non-linearity in the dynamic behavior of the water system and exponential growth of computational complexity with the state and control dimension. To deal with an issue related to non-linearity, we applied simplified internal model based on linearization scheme with a large grid length. For solving curse of dimensionality, we utilize the reduced model in which the states of the system are reduced by considering outflows from uncontrolled catchments as disturbances in the water system. We also address the computational time for real time control by using large time step scheme. Simulation results indicate that this model is able to use for real time control of a reservoir system addressing trade-offs between the multiple objectives.

  14. Natural and Controlled Demineralization for Study Purposes in Minimally Invasive Dentistry.

    PubMed

    Skucha-Nowak, Małgorzata; Gibas, Mirosław; Tanasiewicz, Marta; Twardawa, Henryk; Szklarski, Tomasz

    2015-01-01

    Artificially induced demineralization of enamel is frequently used during laboratory tests, particularly in minimally invasive dentistry. The aim of this study was to analyze demineralization techniques of hard tooth tissue applicable in the research of materials in minimally invasive dentistry. The most important factor taken into consideration when designing a method is to make a model as closely similar to the natural environment of the human oral cavity as it is possible. In vitro models allow us to maintain stability and control over the environment and guarantee repeatability of the results. There are main models to produce dental caries outside of the body. The first model is chemical and it uses acids. It is simplified and reflects the actual environment of the oral cavity to a lesser degree. The second model is biological and it is more accurate as it uses microorganisms which build the dental plaque. Among in vitro protocols are also used pH-cycling models. Based on the available literature, it was found that bovine teeth and human teeth with demineralization diagnosed while still inside the oral cavity are the most frequently used kind of specimens in research conducted with use of the chemical model. Not a single case of use of the biological and pH-cycling models were found in the available literature related to the research of infiltrants in minimally invasive dentistry.

  15. Natural and Controlled Demineralization for Study Purposes in Minimally Invasive Dentistry.

    PubMed

    Skucha-Nowak, Małgorzata; Gibas, Mirosław; Tanasiewicz, Marta; Twardawa, Henryk; Szklarski, Tomasz

    2015-01-01

    Artificially induced demineralization of enamel is frequently used during laboratory tests, particularly in minimally invasive dentistry. The aim of this study was to analyze demineralization techniques of hard tooth tissue applicable in the research of materials in minimally invasive dentistry. The most important factor taken into consideration when designing a method is to make a model as closely similar to the natural environment of the human oral cavity as it is possible. In vitro models allow us to maintain stability and control over the environment and guarantee repeatability of the results. There are main models to produce dental caries outside of the body. The first model is chemical and it uses acids. It is simplified and reflects the actual environment of the oral cavity to a lesser degree. The second model is biological and it is more accurate as it uses microorganisms which build the dental plaque. Among in vitro protocols are also used pH-cycling models. Based on the available literature, it was found that bovine teeth and human teeth with demineralization diagnosed while still inside the oral cavity are the most frequently used kind of specimens in research conducted with use of the chemical model. Not a single case of use of the biological and pH-cycling models were found in the available literature related to the research of infiltrants in minimally invasive dentistry. PMID:26768642

  16. Controlling energy transfer processes and engineering luminescence efficiencies with low dimensional doping

    NASA Astrophysics Data System (ADS)

    Yu, Xiaoqiang; Summers, Christopher J.; Park, Wounjhang

    2012-04-01

    Energy transfer between two optical centers has long been used to promote the down- and up-conversion of light. In conventional phosphors, the two centers are distributed uniformly in 3D space and the luminescence efficiency is generally limited by energy transfer to defect states, where the excitation is quenched through non-radiative processes. In this paper, we present a new concept of low-dimensional doping of pairs of optical centers and explore its effect on enhancing the efficiency of down- and up-converted luminescence. The concept takes advantage of the fact that the low-dimensional doping profile significantly reduces the energy transfer rate to unintentional defects, which are naturally distributed in 3D space. The resultant de-coupling between optical centers and defects can lead to a substantial increase in luminescence efficiency. We first present the theoretical framework and apply the theory to well-characterized down- and up-conversion phosphors. For BaMgAl10O17:Eu2+, Mn2+ down-conversion phosphor, a factor of two increase in efficiency is predicted. For Na2Y3F11:Yb3+, Er3+ up-conversion phosphor, low-dimensional doping did not lead to increase in efficiency. This is because the major quenching mechanism is cross-relaxation between Er3+ ions, not energy transfer to defects. In an ideal up-conversion phosphor, where defect quenching is the dominant loss mechanism, similar increases (by a factor of 2-5) are predicted. This work presents a new pathway to engineer luminescent materials and achieve high luminescence efficiencies in up- and down-conversion phosphors.

  17. Electrically controllable plasmonic enhanced coherent random lasing from dye-doped nematic liquid crystals containing Au nanoparticles.

    PubMed

    Wang, Lei; Wan, Yuan; Shi, Lijie; Zhong, Haizheng; Deng, Luogen

    2016-08-01

    An electrically controllable plasmonic enhanced coherent random lasing from the dye-doped nematic liquid crystal containing Au nanoparticles is demonstrated. To achieve the optimal control of the RL properties, the polarization of the pump light should be parallel to the rubbing direction of the cells. The lasing output intensity is direction-dependent and the substantial output distributes in an angle range of 0°~30° deviating from the direction of the pump stripe. The coherent feedback associated with the coherent random lasing mainly originates from the cooperative effect of the enhanced localized electric field in the vicinity of Au nanoparticles and the multiple scattering caused by the fluctuations of the liquid crystal director and local dielectric tensor. PMID:27505729

  18. Manipulation of operation states by polarization control in an erbium-doped fiber laser with a hybrid saturable absorber.

    PubMed

    Lin, Kuei-Huei; Kang, Jung-Jui; Wu, Hsiao-Hua; Lee, Chao-Kuei; Lin, Gong-Ru

    2009-03-16

    We propose an operation switchable ring-cavity erbium-doped fiber laser (EDFL) via intra-cavity polarization control. By using a semiconductor saturable absorber mirror in the EDFL cavity, stable Q-switching, Q-switched mode-locking, continuous-wave mode-locking, pulse splitting, and harmonic mode-locking pulses can be manipulated simply by detuning a polarization controller while keeping the pump power at the same level. All EDFL operation states can be obtained under the polarization angles detuning within 180 degrees. Continuous-wave mode-locking of EDFL with 800-fs pulsewidth repeated at 4 MHz has been obtained, for which the output pulse energy is 0.5 nJ and the peak power is 625 W. Interaction between solitons and the accompanied non-soliton component will lead to either pulse splitting or 5th-order harmonic mode-locking at repetition rate of 20 MHz.

  19. Light-controlled electric Freedericksz threshold in dye doped liquid crystals

    SciTech Connect

    Lucchetti, L.; Catani, L.; Simoni, F.

    2014-05-28

    We report the results of measurements of the threshold of Freedericksz transition in a nematic liquid crystal doped by Methyl-red. We show that in case of dc field the threshold voltage can decrease or increase depending on the light dose, due to the light-induced desorption and adsorption of charge complexes from and on the irradiated surface, that has been recently demonstrated. This effect has the potential to be exploited in optical devices such as liquid crystal microlenses and spatial light modulators.

  20. Nitrogen doped TiO2 nano-particles: Phase control by solution combustion method

    NASA Astrophysics Data System (ADS)

    Bapna, Komal; Choudhary, R. J.; Phase, D. M.; Shastri, Sheetal; Prasad, R.; Ahuja, B. L.

    2016-05-01

    N-doped TiO2 nano powders were prepared by sol-gel solution combustion method. The influence of different fuels (urea and citric acid) used in obtaining N-TiO2 nano particles in similar conditions (heat treatment, amount of precursors) has been investigated. The growth of different phases of TiO2 (anatase and rutile) is strongly affected by the ligands and the dehydration reaction. Reduction in the band gap of TiO2 and features observed in the XPS spectra confirm the incorporation of N into TiO2 matrix.

  1. Enhancement of thermoelectric figure of merit in β-Zn{sub 4}Sb{sub 3} by indium doping control

    SciTech Connect

    Wei, Pai-Chun E-mail: cheny2@phys.sinica.edu.tw; Hsu, Chia-Hao; Chang, Chung-Chieh; Chen, Cheng-Lung; Wu, Maw-Kuen; Chen, Yang-Yuan E-mail: cheny2@phys.sinica.edu.tw; Yang, Chun-Chuen; Chen, Jeng-Lung; Sankar, Raman; Chou, Fang-Cheng; Chen, Chi-Liang; Dong, Chung-Li; Chen, Kuei-Hsien

    2015-09-21

    We demonstrate the control of phase composition in Bridgman-grown β-Zn{sub 4}Sb{sub 3} crystals by indium doping, an effective way to overcome the difficulty of growing very pure β-Zn{sub 4}Sb{sub 3} thermoelectric material. The crystal structures are characterized by Rietveld refinement with synchrotron X-ray diffraction data. The results show an anisotropic lattice expansion in In-doped β-Zn{sub 4}Sb{sub 3} wherein the zinc atoms are partially substituted by indium ones at 36f site of R-3c symmetry. Through the elimination of ZnSb phase, all the three individual thermoelectric properties are simultaneously improved, i.e., increasing electrical conductivity and Seebeck coefficient while reducing thermal conductivity. Under an optimal In concentration (x = 0.05), pure phase β-Zn{sub 4}Sb{sub 3} crystal can be obtained, which possesses a high figure of merit (ZT) of 1.4 at 700 K.

  2. Controllable synthesis and upconversion emission of ultrasmall lanthanide-doped Sr2GdF7 nanocrystals

    NASA Astrophysics Data System (ADS)

    Xiang, Lijun; Ren, Guozhong; Mao, Yifu; He, Jin; Su, Rui

    2015-11-01

    The effect of rare-earth ions content on the phase structure, crystal size and morphology of SrF2-GdF3 system were studied under solvothermal conditions. By tuning the molar ratio of reactants, tetragonal phase Sr2GdF7 nanocrystals (NCs) were synthesized via solvothermal method using oleic acid as capping ligands. The effects of reaction conditions on the phase structure, crystal size, morphology, and upconversion (UC) emission properties of the products were investigated. The results reveal that apropos Gd3+ ions content (0.30-0.45 mmol) is favorable to the formation of pure phase Sr2GdF7 NCs with more uniform size distribution. The average crystalline size of the products can be controlled less than 10 nm. The energy transfer UC mechanisms for the fluorescent intensity were also investigated. Following Yb3+, Er3+, Tm3+ and Ho3+ ions doping, the Sr2GdF7 NCs show intense green, yellow, and white-color UC emission under the excitation of a 980 nm laser, and the doping concentration of lanthanide ions was optimized, which makes the NCs show maximum intensities under the excitation of a 980 nm laser.

  3. Manipulation and control of the interfacial polarization in organic light-emitting diodes by dipolar doping

    NASA Astrophysics Data System (ADS)

    Jäger, Lars; Schmidt, Tobias D.; Brütting, Wolfgang

    2016-09-01

    Most of the commonly used electron transporting materials in organic light-emitting diodes exhibit interfacial polarization resulting from partially aligned permanent dipole moments of the molecules. This property modifies the internal electric field distribution of the device and therefore enables an earlier flat band condition for the hole transporting side, leading to improved charge carrier injection. Recently, this phenomenon was studied with regard to different materials and degradation effects, however, so far the influence of dilution has not been investigated. In this paper we focus on dipolar doping of the hole transporting material 4,4-bis[N-(1-naphthyl)-N-phenylamino]-biphenyl (NPB) with the polar electron transporting material tris-(8-hydroxyquinolate) aluminum (Alq3). Impedance spectroscopy reveals that changes of the hole injection voltage do not scale in a simple linear fashion with the effective thickness of the doped layer. In fact, the measured interfacial polarization reaches a maximum value for a 1:1 blend. Taking the permanent dipole moment of Alq3 into account, an increasing degree of dipole alignment is found for decreasing Alq3 concentration. This observation can be explained by the competition between dipole-dipole interactions leading to dimerization and the driving force for vertical orientation of Alq3 dipoles at the surface of the NPB layer.

  4. [Point of view on doping].

    PubMed

    Naeije, R; Pagnamenta, A

    1999-06-01

    Doping is defined as the administration of or use by competing athletes of any substance foreign to the body or of any physiological substance taken in abnormal quantity or taken by an abnormal route of entry into the body with the sole intention of increasing in an artificial and unfair manner his/her performance in competition. The prevalence of doping has been estimated by rigorous methods to be 5-15%. The only two dopings of established efficacy are: anabolic steroids for resistive performance, and blood doping for endurance performance. Although medical control of athletes is reputably poor, reported accidents attributable to doping have been until now very rare. Doping is unfair, and must as such be banned from competitions. Medicalized doping is unethical. More studies are required to improve knowledge of doping as a public health issue. Sports medicine is in need of scientific and moral revalorization.

  5. Epitaxy-enabled vapor-liquid-solid growth of tin-doped indium oxide nanowires with controlled orientations.

    PubMed

    Shen, Youde; Turner, Stuart; Yang, Ping; Van Tendeloo, Gustaaf; Lebedev, Oleg I; Wu, Tom

    2014-08-13

    Controlling the morphology of nanowires in bottom-up synthesis and assembling them on planar substrates is of tremendous importance for device applications in electronics, photonics, sensing and energy conversion. To date, however, there remain challenges in reliably achieving these goals of orientation-controlled nanowire synthesis and assembly. Here we report that growth of planar, vertical and randomly oriented tin-doped indium oxide (ITO) nanowires can be realized on yttria-stabilized zirconia (YSZ) substrates via the epitaxy-assisted vapor-liquid-solid (VLS) mechanism, by simply regulating the growth conditions, in particular the growth temperature. This robust control on nanowire orientation is facilitated by the small lattice mismatch of 1.6% between ITO and YSZ. Further control of the orientation, symmetry and shape of the nanowires can be achieved by using YSZ substrates with (110) and (111), in addition to (100) surfaces. Based on these insights, we succeed in growing regular arrays of planar ITO nanowires from patterned catalyst nanoparticles. Overall, our discovery of unprecedented orientation control in ITO nanowires advances the general VLS synthesis, providing a robust epitaxy-based approach toward rational synthesis of nanowires. PMID:24971997

  6. Controllable synthesis of helical, straight, hollow and nitrogen-doped carbon nanofibers and their magnetic properties

    SciTech Connect

    Li, Xun; Xu, Zheng

    2012-12-15

    Graphical abstract: The helical, straight and hollow carbon nanofibers can be selectively synthesized by adjusting either the reaction temperature or feed gas composition. Display Omitted Highlights: ► CNFs were synthesized via pyrolysis of acetylene on copper NPs. ► The helical, straight, hollow and N-doped CNFs can be selectively synthesized. ► The growth mechanism of different types of CNFs was proposed. -- Abstract: Carbon nanofibers (CNFs) with various morphologies were synthesized by catalytic pyrolysis of acetylene on copper nanoparticles which were generated from the in situ decomposition of copper acetylacetonate. The morphology of the pristine and acid-washed CNFs was investigated by field emission scanning electron microscope and high-resolution transmission electron microscope. Helical, straight and hollow CNFs can be selectively synthesized by adjusting either the reaction temperature or feed gas composition. The growth mechanism for these three types of CNFs was proposed.

  7. Incorporation of DOPE into Lipoplexes formed from a Ferrocenyl Lipid leads to Inverse Hexagonal Nanostructures that allow Redox-Based Control of Transfection in High Serum

    PubMed Central

    Muller, John P. E.; Aytar, Burcu S.; Kondo, Yukishige; Lynn, David M.; Abbott, Nicholas L.

    2012-01-01

    We report small angle X-ray and neutron scattering measurements that reveal that mixtures of the redox-active lipid bis(11-ferrocenylundecyl)dimethylammonium bromide (BFDMA) and dioleoylphosphatidylethanolamine (DOPE) spontaneously form lipoplexes with DNA that exhibit inverse hexagonal nanostructure (HIIc). In contrast to lipoplexes of DNA and BFDMA only, which exhibit a multilamellar nanostructure (Lαc) and limited ability to transfect cells in the presence of serum proteins, we measured lipoplexes of BFDMA and DOPE with the HIIc nanostructure to survive incubation in serum and to expand significantly the range of media compositions (e.g., up to 80% serum) over which BFDMA can be used to transfect cells with high efficiency. Importantly, we also measured the oxidation state of the ferrocene within the BFDMA/DNA lipoplexes to have a substantial influence on the transfection efficiency of the lipoplexes in media containing serum. Specifically, whereas lipoplexes of reduced BFDMA and DOPE transfect cells with high efficiency, lipoplexes of oxidized BFDMA and DNA lead to low levels of transfection. Complementary measurements using SAXS reveal that the low transfection efficiency of the lipoplexes of oxidized BFDMA and DOPE correlates with the presence of weak Bragg peaks and thus low levels of HIIc nanostructure in solution. Overall, these results provide support for our hypothesis that DOPE-induced formation of the HIIc nanostructure of the BFDMA-containing lipoplexes underlies the high cell transfection efficiency measured in the presence of serum, and that the oxidation state of BFDMA within lipoplexes with DOPE substantially regulates the formation of the HIIc nanostructure and thus the ability of the lipoplexes to transfect cells with DNA. More generally, the results presented in this paper suggest that lipoplexes formed from BFDMA and DOPE may offer the basis of approaches that permit active and external control of transfection of cells in the presence of high

  8. Strain-controlled electronic properties and magnetorelaxor behaviors in electron-doped CaMnO3 thin films

    NASA Astrophysics Data System (ADS)

    Xiang, P.-H.; Yamada, H.; Sawa, A.; Akoh, H.

    2009-02-01

    We have fabricated epitaxial thin films of electron-doped manganite Ca1-xCexMnO3 (CCMO) with 0≤x≤0.08. The transport properties of CCMO films are very sensitive to substrate-controlled epitaxial strain. For the CCMO(x =0.05) film, the metallic transport characteristic is observed only on a nearly lattice-matched NdAlO3 (NAO) substrate, while tensilely and compressively stressed films are insulating. The CCMO(x =0.06) film on the NAO substrate shows a large magnetoresistance characteristic of a magnetorelaxor. This behavior can be explained in terms of the phase separation and the irreversible growth of the metallic domain in antiferromagnetic insulating matrix.

  9. Pr3+/Yb3+ co-doped beta-phase NaYF4 microprisms: controlled synthesis and upconversion luminescence.

    PubMed

    Gao, Wei; Zheng, Hairong; Gao, Dangli; He, Enjie; Li, Jiao; Tu, Yinxun

    2014-06-01

    Pr3+/Yb3+ co-doped hexagonal NaYF4(beta-NaYF4) microprisms were synthesized by the hydrothermal method, and ethylenediaminetetraacetic acid (EDTA) was introduced to control the size of the microcrystal samples. Bright upconverted fluorescence emission was observed when the samples were excited with an infrared (IR) laser at 976.4 nm. The emission was found to originate from the transitions of 3P0-3F2, 3P0-3H6 or 1G4-3H4, 3P1-3H6, 3P0-3H5, 3P1-3H5, and 3P0-3H4 of Pr3+ ions. Possible mechanisms for upconversion fluorescence and concentration dependence as well as the crystal structure and its formation of NaYF4:Yb3+/Pr3+ microprisms were explored and discussed based on the experimental observations.

  10. Kesterite Cu2Zn(Sn,Ge)(S,Se)4 thin film with controlled Ge-doping for photovoltaic application.

    PubMed

    Zhao, Wangen; Pan, Daocheng; Liu, Shengzhong Frank

    2016-05-21

    Cu2ZnSn(S,Se)4 (CZTSSe) semiconductors have been a focus of extensive research effort owing to low-toxicity, high abundance and low material cost. Yet, the CZTSSe thin film solar cell has a low open-circuit voltage value that presents challenges. Herein, using GeSe2 as a new Ge source material, we have achieved a wider band gap CZTSSe-based semiconductor absorber layer with its band-gap controlled by adjusting the ratio of SnS2 : GeSe2 used. In addition, the Cu2Zn(Sn,Ge)(S,Se)4 thin films were prepared with optimal Ge doping (30%) and solar cells were fabricated to attain a respectable power conversion efficiency of 4.8% under 1.5 AM with an active area of 0.19 cm(2) without an anti-reflection layer. PMID:27121893

  11. Pr3+/Yb3+ co-doped beta-phase NaYF4 microprisms: controlled synthesis and upconversion luminescence.

    PubMed

    Gao, Wei; Zheng, Hairong; Gao, Dangli; He, Enjie; Li, Jiao; Tu, Yinxun

    2014-06-01

    Pr3+/Yb3+ co-doped hexagonal NaYF4(beta-NaYF4) microprisms were synthesized by the hydrothermal method, and ethylenediaminetetraacetic acid (EDTA) was introduced to control the size of the microcrystal samples. Bright upconverted fluorescence emission was observed when the samples were excited with an infrared (IR) laser at 976.4 nm. The emission was found to originate from the transitions of 3P0-3F2, 3P0-3H6 or 1G4-3H4, 3P1-3H6, 3P0-3H5, 3P1-3H5, and 3P0-3H4 of Pr3+ ions. Possible mechanisms for upconversion fluorescence and concentration dependence as well as the crystal structure and its formation of NaYF4:Yb3+/Pr3+ microprisms were explored and discussed based on the experimental observations. PMID:24738388

  12. Mass spectrometric characterization of urinary metabolites of the selective androgen receptor modulator S-22 to identify potential targets for routine doping controls.

    PubMed

    Thevis, Mario; Thomas, Andreas; Möller, Ines; Geyer, Hans; Dalton, James T; Schänzer, Wilhelm

    2011-08-15

    Drugs that promote anabolic processes with limited undesirable effects are of considerable therapeutic interest; some notable examples include those for the treatment of cancer cachexia and muscle-wasting diseases. Anabolic properties are not only therapeutically beneficial to critically ill and debilitated patients, but are also desirable to athletes seeking artificial enhancements in endurance, strength and accelerated recovery. The use of anabolic agents in the clinical setting is being reconsidered with the emergence of a new class of drugs referred to as SARMs (selective androgen receptor modulators). SARMs have the potential to complement or even replace anabolic androgenic steroidal use with the benefit of a reduction of the undesirable side effects associated with steroid administration alone. Arylpropionamide-based SARMs such as andarine (S-4) and S-22 have shown promising therapeutic properties and have attracted the interest of elite and amateur athletes despite the absence of clinical approval, and evidence for trafficking and misuse in sport has been obtained by doping control authorities. In this communication, the elucidation of urinary metabolites of the SARM drug candidate S-22 is compared with earlier in vitro metabolism studies. Following oral administration of illicit S-22, urine samples were collected after 62 and 135 h and analyzed for the active drug and its major metabolic products. Liquid chromatography interfaced with high-resolution/high-accuracy (tandem) mass spectrometry was used to identify and/or confirm the predicted target analytes for sports drug testing purposes. S-22 was detected in both specimens accompanied by its glucuronic acid conjugate. This was the B-ring hydroxylated derivative of S-22 plus the corresponding glucuronide (with the phase-II metabolites being the more abundant analytes). In addition, the samples collected 62 h post-administration also contained the phase-I metabolite hydroxylated at the methyl residue (C-20

  13. Mass spectrometric characterization of urinary metabolites of the selective androgen receptor modulator S-22 to identify potential targets for routine doping controls.

    PubMed

    Thevis, Mario; Thomas, Andreas; Möller, Ines; Geyer, Hans; Dalton, James T; Schänzer, Wilhelm

    2011-08-15

    Drugs that promote anabolic processes with limited undesirable effects are of considerable therapeutic interest; some notable examples include those for the treatment of cancer cachexia and muscle-wasting diseases. Anabolic properties are not only therapeutically beneficial to critically ill and debilitated patients, but are also desirable to athletes seeking artificial enhancements in endurance, strength and accelerated recovery. The use of anabolic agents in the clinical setting is being reconsidered with the emergence of a new class of drugs referred to as SARMs (selective androgen receptor modulators). SARMs have the potential to complement or even replace anabolic androgenic steroidal use with the benefit of a reduction of the undesirable side effects associated with steroid administration alone. Arylpropionamide-based SARMs such as andarine (S-4) and S-22 have shown promising therapeutic properties and have attracted the interest of elite and amateur athletes despite the absence of clinical approval, and evidence for trafficking and misuse in sport has been obtained by doping control authorities. In this communication, the elucidation of urinary metabolites of the SARM drug candidate S-22 is compared with earlier in vitro metabolism studies. Following oral administration of illicit S-22, urine samples were collected after 62 and 135 h and analyzed for the active drug and its major metabolic products. Liquid chromatography interfaced with high-resolution/high-accuracy (tandem) mass spectrometry was used to identify and/or confirm the predicted target analytes for sports drug testing purposes. S-22 was detected in both specimens accompanied by its glucuronic acid conjugate. This was the B-ring hydroxylated derivative of S-22 plus the corresponding glucuronide (with the phase-II metabolites being the more abundant analytes). In addition, the samples collected 62 h post-administration also contained the phase-I metabolite hydroxylated at the methyl residue (C-20

  14. Room-temperature ferromagnetism in Cr-doped Si achieved by controlling atomic structure, Cr concentration, and carrier densities: A first-principles study

    SciTech Connect

    Wei, Xin-Yuan; Yang, Zhong-Qin; Zhu, Yan; Li, Yun

    2015-04-28

    By using first-principles calculations, we investigated how to achieve a strong ferromagnetism in Cr-doped Si by controlling the atomic structure and Cr concentration as well as carrier densities. We found that the configuration in which the Cr atom occupies the tetrahedral interstitial site can exist stably and the Cr atom has a large magnetic moment. Using this doping configuration, room-temperature ferromagnetism can be achieved in both n-type and p-type Si by tuning Cr concentration and carrier densities. The results indicate that the carrier density plays a crucial role in realizing strong ferromagnetism in diluted magnetic semiconductors.

  15. Room-temperature ferromagnetism in Cr-doped Si achieved by controlling atomic structure, Cr concentration, and carrier densities: A first-principles study

    NASA Astrophysics Data System (ADS)

    Wei, Xin-Yuan; Zhu, Yan; Yang, Zhong-Qin; Li, Yun

    2015-04-01

    By using first-principles calculations, we investigated how to achieve a strong ferromagnetism in Cr-doped Si by controlling the atomic structure and Cr concentration as well as carrier densities. We found that the configuration in which the Cr atom occupies the tetrahedral interstitial site can exist stably and the Cr atom has a large magnetic moment. Using this doping configuration, room-temperature ferromagnetism can be achieved in both n-type and p-type Si by tuning Cr concentration and carrier densities. The results indicate that the carrier density plays a crucial role in realizing strong ferromagnetism in diluted magnetic semiconductors.

  16. Control of the visible emission in the SrZrO3 nano-crystals with the rare earth ion doping.

    PubMed

    Kim, Dong Hwan; Kim, Ji Hyun; Chung, Jin Seok; Lee, Yunsang

    2013-11-01

    We investigated the emission property of SrZrO3 nano-crystals (NCs) with the doping of rare earth (RE) ions, Eu3+ and Tm3+, by using 325 nm photo-excitation. SrZrO3 NCs show a sizable violet-blue emission, while the Eu3+ and Tm3+ ions are well known to be good red and blue phosphors, respectively. Combined emissions of the host and the RE ion dopant might suggest a new white luminescent source. The RE ion doped SrZrO3 NCs were initially synthesized by using the combustion method, and then the as-synthesized crystals were annealed at different temperatures from 650 degrees C to 1450 degrees C. The Eu3+-doped SrZrO3 NCs showed the sharp red emission near 600 nm, in addition to a violet-blue emission of the host material in itself. While the red emission is enhanced in the high temperature post-annealing, the blue emission is suppressed in an opposite way. This close relation between the emissions of the host and dopant was observed similarly in the Tm3+-doped NCs. We could control the emission property in the SrZrO3:Eu3+/Tm3+ NCs from blue to red by thermal annealing and RE ion doping.

  17. Controllable synthesis of flake-like Al-doped ZnO nanostructures and its application in inverted organic solar cells

    PubMed Central

    2011-01-01

    Flake-like Al-doped ZnO (AZO) nanostructures including dense AZO nanorods were obtained via a low-temperature (100°C) hydrothermal process. By doping and varying Al concentrations, the electrical conductivity (σ) and morphology of the AZO nanostructures can be readily controlled. The effect of σ and morphology of the AZO nanostructures on the performance of the inverted organic solar cells (IOSCs) was studied. It presents that the optimized power conversion efficiency of the AZO-based IOSCs is improved by approximately 58.7% compared with that of un-doped ZnO-based IOSCs. This is attributed to that the flake-like AZO nanostructures of high σ and tunable morphology not only provide a high-conduction pathway to facilitate electron transport but also lead to a large interfacial area for exciton dissociation and charge collection by electrodes. PMID:21970654

  18. Controlling Proton Conductivity with Light: A Scheme Based on Photoacid Doping of Materials.

    PubMed

    Haghighat, Shima; Ostresh, Sarah; Dawlaty, Jahan M

    2016-02-11

    Transducing light energy to changes in material properties is central to a large range of functional materials, including those used in light harvesting. In conventional semiconductors, photoconductivity arises due to generation of mobile electrons or holes with light. Here we demonstrate, to our knowledge for the first time, an analogue of this effect for protons in an organic polymer solution and in water. We show that when a material is doped with photoacids, light excitation generates extra mobile protons that change the low-frequency conductivity of the material. We measure such change both in poly(ethylene glycol) (PEG) and in water sandwiched between two transparent electrodes and doped with a well-known photoacid 8-hydroxypyrene-1,3,6-trisulfonic acid (HPTS). The complex impedance of the material is measured over a range of 0.1 Hz-1 MHz in both the presence and absence of light, and it is found that shining light changes the low frequency impedance significantly. We model the impedance spectra of the material with a minimal circuit composed of a diffusive impedance (Warburg element), a parallel capacitance, and a resistance. Fitting the light and dark impedance spectra to the model reveals that light reduces the low-frequency diffusive impedance of the material, which is consistent with generation of extra free carriers by light. We further suggest that the light-induced conductivity change arises mainly due to those photoreleased protons that manage to escape the zone of influence of the parent ion and avoid recapture. Such escape is more likely in materials with larger diffusion coefficient for protons and shorter electrostatic screening lengths for the parent ion. This explanation is consistent with our observed differences in the photoconductivity of solution of HPTS in water and in PEG. We anticipate that this scheme can be employed in protonic circuits where direct transduction of energy from light to protonic gradients or protonic currents is

  19. Multi-purpose droop controllers incorporating a passivity-based stabilizer for unified control of electronically interfaced distributed generators including primary source dynamics.

    PubMed

    Azimi, Seyed Mohammad; Afsharnia, Saeed

    2016-07-01

    This paper presents multi-purpose droop controllers for electronically-interfaced distributed generators (EI-DGs). These controllers allow the micro-grids to operate in grid-connected mode, islanded mode and mode transition transients with a unique control configuration. The active and reactive-power sharing among EI-DGs are satisfied by the proposed droop controllers in islanded mode. On the other hand, in the grid-connected mode, the droop controllers adjust the output active and reactive-powers of EI-DGs at the pre-programmed constant levels. The provision of sufficient damping capability and maintenance of the transient stability in all operational modes of EI-DGs are warranted by the suggested stabilizer. This stabilizer, which is designed using the passivity-based control (PBC) approach, is incorporated in the droop controllers to dampen power-angle, frequency and voltage deviations during large transients using solely local information. The primary source dynamics of EI-DGs are also considered. It is analytically proven that the presence of the primary source dynamics leads to attenuation of the damping capability of EI-DGs in transients. To compensate the adverse effect of the primary source dynamics during transients a novel compensator is inserted in the frequency-droop loop. Finally, time-domain simulations are performed on a multi-resources MG to verify the analytical results compared to those obtained, based on a recently-developed strategy.

  20. Short term impact of Tribulus terrestris intake on doping control analysis of endogenous steroids.

    PubMed

    Saudan, Christophe; Baume, Norbert; Emery, Caroline; Strahm, Emmanuel; Saugy, Martial

    2008-06-10

    Tribulus terrestris is a nutritional supplement highly debated regarding its physiological and actual effects on the organism. The main claimed effect is an increase of testosterone anabolic and androgenic action through the activation of endogenous testosterone production. Even if this biological pathway is not entirely proven, T. terrestris is regularly used by athletes. Recently, the analysis of two female urine samples by GC/C/IRMS (gas chromatography/combustion/isotope-ratio-mass-spectrometry) conclusively revealed the administration of exogenous testosterone or its precursors, even if the testosterone glucuronide/epitestosterone glucuronide (T/E) ratio and steroid marker concentrations were below the cut-off values defined by World Anti-Doping Agency (WADA). To argue against this adverse analytical finding, the athletes recognized having used T. terrestris in their diet. In order to test this hypothesis, two female volunteers ingested 500 mg of T. terrestris, three times a day and for two consecutive days. All spot urines were collected during 48 h after the first intake. The (13)C/(12)C ratio of ketosteroids was determined by GC/C/IRMS, the T/E ratio and DHEA concentrations were measured by GC/MS and LH concentrations by radioimmunoassay. None of these parameters revealed a significant variation or increased above the WADA cut-off limits. Hence, the short-term treatment with T. terrestris showed no impact on the endogenous testosterone metabolism of the two subjects.

  1. Doping control analysis for adrafinil and its major metabolites in human urine.

    PubMed

    Lu, Jianghai; Wang, Xiaobing; Yang, Shuming; Liu, Xin; Qin, Yang; Shen, Li; Wu, Yun; Xu, Youxuan; Wu, Moutian; Ouyang, Gangfeng

    2009-06-01

    A new and reliable two-step liquid chromatography/tandem mass spectrometry (LC/MS/MS) method in combination with gas chromatography/mass spectrometry (GC/MS) for the screening and confirmation of adrafinil and its major metabolites, modafinil and modafinil acid, in human urine has been developed and validated. The method involved reversed-phase C18 solid-phase extraction (SPE) cartridge extraction and MS analysis by means of LC/MS/MS and GC/MS. The study illustrated that the ESI capillary temperature played a key role in the formation of the protonated molecule. The limits of detection (LODs) of the developed method for the three compounds were lower than the minimum required performance limit (MRPL) of the World Anti-Doping Agency (WADA). The human urine samples obtained after the oral administration of modafinil and from the Beijing 2008 Olympic Games were analyzed by using the described method, which has also been successfully applied to routine analyses and the WADA Proficiency Test. PMID:19399790

  2. Native fluorescent detection with sequential injection chromatography for doping control analysis

    PubMed Central

    2013-01-01

    Background Sequential injection chromatography (SIC) is a young, ten years old, separation technique. It was proposed with the benefits of reagent-saving, rapid analysis, system miniaturization and simplicity. SIC with UV detection has proven to be efficient mostly for pharmaceutical analysis. In the current study, a stand-alone multi-wavelength fluorescence (FL) detector was coupled to an SIC system. The hyphenation was exploited for developing an SIC-FL method for the separation and quantification of amiloride (AML) and furosemide (FSM) in human urine and tablet formulation. Results AML and FSM were detected using excitation maxima at 380 and 270 nm, respectively, and emission maxima at 413 and 470 nm, respectively. The separation was accomplished in less than 2.0 min into a C18 monolithic column (50 × 4.6 nm) with a mobile phase containing 25 mmol/L phosphate buffer (pH 4.0): acetonitrile: (35:65, v/v). The detection limits were found to be 12 and 470 ng/mL for AML and FSM, respectively. Conclusions The proposed SIC-FL method features satisfactory sensitivity for AML and FSM in urine samples for the minimum required performance limits recommended by the World Anti-Doping Agency, besides a downscaled consumption of reagents and high rapidity for industrial-scale analysis of pharmaceutical preparations. PMID:23985079

  3. Enhancement of cells proliferation and control of bioactivity of strontium doped glass

    NASA Astrophysics Data System (ADS)

    Oudadesse, H.; Dietrich, E.; Bui, X. V.; Le Gal, Y.; Pellen, P.; Cathelineau, G.

    2011-08-01

    Bioactivity and chemical reactivity of bioactive glass offer the ability to bond for soft and hard biological tissues. In this work, synthesis was carried out by using melting and rapid quenching. Strontium was introduced as trace element at different contents in the glass matrix, according to its concentration in the bone matrix. This chemical element presents a high interest in the bone metabolism activity. Investigations were conducted on the surface of biomaterials by using in vitro assay after immersion in SBF. Several physico-chemical methods such as SEM, FTIR, NMR, ICP-OES and MTT test were employed to highlight the effects of the Sr. The in vitro experiments showed that after soaking in SBF, the behaviour of pure glass is different compared to glass doped with Sr. NMR analyses showed in the 29Si MAS-NMR that glass matrix undergoes some changes after in vitro assays particularly the emergence of new components attributed to Q 3(OH). The presence of Sr slowed down the bioactivity of glass after immersion in SBF. The non toxic character of compounds was confirmed. Introduction of Sr at 0.1 wt % induce an enhancement of cells at about 14.3%.

  4. Three-dimensional object-oriented modeling of the stomach for the purpose of microprocessor-controlled functional stimulation.

    PubMed

    Rashev, Peter Z; Bowes, Kenneth L; Mintchev, Martin P

    2002-12-01

    Three-dimensional (3-D) object-oriented models are needed for optimizing gastric electrical stimulation by performing virtual computer experiments. The aim of the study was to create a 3-D object-oriented electromechanical model of the stomach in vivo for the purpose of microprocessor controlled functional stimulation. The stomach was modeled using coaxial truncated conoids as objects. The strength of an external stimulating electric field generated by circumferentially implanted wire electrodes is related to artificial neurogenic and myogenic control of smooth muscle depolarization and contraction. Variation of the field strength modulates the frequency and concentration of acetylcholine release, as well as the transmembrane voltage of the muscle cells. Mechanical response of the stimulated tissue was quantified by two parametric functions of the electric field strength representing the relative contractile force and geometrical displacement of the gastric surface. Data from previously conducted canine experiments were used to test the validity of the model. The model was applied to simulate contractions with different positions, orientation and number of the circumferentially implanted stimulating electrodes. The model combined most of the existing theoretical and experimental findings concerning functional gastric stimulation and can be utilized as a flexible tool for virtual medical tests involving external high-frequency (50 Hz) neural stimulation.

  5. Size-controlled growth of spherical nanoparticles of Y-doped BaZrO3 perovskite

    NASA Astrophysics Data System (ADS)

    Srinivas Reddy, G.; Bauri, Ranjit

    2016-04-01

    Yttrium-doped BaZrO3 (BZY) was processed by a simple yet effective chemical synthesis route that yielded perfectly spherical particles. The particle size was found to decrease with increasing molar concentration of cations in the solution. Thus, the process offered a great ease of controlling the particle size as well. The close control over morphology and size can provide an opportunity of tuning the properties of such particles. The average particle size as obtained from high-resolution scanning electron microscopy (HR-SEM) was 243, 206, 149, and 79 nm at 0.2, 0.5, 0.8, and 1 M concentration, respectively. At a processing temperature of 60 °C, the undesirable phases, BaCO3 and Zr1-xYxO2, were present along with BZY even after calcination at 600 °C, and it took a very long processing time (160 min) for complete phase formation. The BZY phase formed within 45 min at a reaction temperature of 90 °C and yielded phase pure powders on calcination at the same temperature (600 °C). The d-spacing (2.98 Å) obtained from the lattice fringes in high-resolution transmission electron microscopy (HR-TEM) confirmed the cubic perovskite phase of BaZrO3. The average crystallite size calculated from XRD analysis coupled with the TEM observations revealed that each spherical particle consists of only few crystallites.

  6. Control of the local devitrification on oxyfluoride glass doped with Er{sup 3+} ions under diode laser irradiation

    SciTech Connect

    Gonzalez-Perez, S.; Martin, I. R.; Jaque, D.; Haro-Gonzalez, P.; Capuj, N.

    2010-11-15

    Temperature control of the devitrification process in an erbium doped oxyfluoride glass under laser irradiation is reported. The green upconversion emissions around 525 and 545 nm originated from the thermalized {sup 2}H{sub 11/2} and {sup 4}S{sub 3/2} levels were studied when the glass structure changes to glass ceramic during irradiation with a laser beam. Power dependence of the fluorescence intensity ratio was used to determine the temperature of the irradiated zone. The transition from glass to glass ceramic takes place under 2300 mW of laser power with an estimated temperature around 783 K. This result agrees with the one obtained in the samples devitrified under conventional furnace treatment. Therefore, the estimation of the temperature of the irradiated zone through the fluorescence intensity ratio method allows a controlled devitrification. Moreover, an irradiated line has been written in the glass showing an important diffusion of the Pb{sup 2+} and F{sup -} ions. These results confirm that nanocrystals have been created due to the laser action.

  7. Current trends in mass spectrometry of peptides and proteins: Application to veterinary and sports-doping control.

    PubMed

    van den Broek, Irene; Blokland, Marco; Nessen, Merel A; Sterk, Saskia

    2015-01-01

    Detection of misuse of peptides and proteins as growth promoters is a major issue for sport and food regulatory agencies. The limitations of current analytical detection strategies for this class of compounds, in combination with their efficacy in growth-promoting effects, make peptide and protein drugs highly susceptible to abuse by either athletes or farmers who seek for products to illicitly enhance muscle growth. Mass spectrometry (MS) for qualitative analysis of peptides and proteins is well-established, particularly due to tremendous efforts in the proteomics community. Similarly, due to advancements in targeted proteomic strategies and the rapid growth of protein-based biopharmaceuticals, MS for quantitative analysis of peptides and proteins is becoming more widely accepted. These continuous advances in MS instrumentation and MS-based methodologies offer enormous opportunities for detection and confirmation of peptides and proteins. Therefore, MS seems to be the method of choice to improve the qualitative and quantitative analysis of peptide and proteins with growth-promoting properties. This review aims to address the opportunities of MS for peptide and protein analysis in veterinary control and sports-doping control with a particular focus on detection of illicit growth promotion. An overview of potential peptide and protein targets, including their amino acid sequence characteristics and current MS-based detection strategies is, therefore, provided. Furthermore, improvements of current and new detection strategies with state-of-the-art MS instrumentation are discussed for qualitative and quantitative approaches.

  8. Kesterite Cu2Zn(Sn,Ge)(S,Se)4 thin film with controlled Ge-doping for photovoltaic application

    NASA Astrophysics Data System (ADS)

    Zhao, Wangen; Pan, Daocheng; Liu, Shengzhong (Frank)

    2016-05-01

    Cu2ZnSn(S,Se)4 (CZTSSe) semiconductors have been a focus of extensive research effort owing to low-toxicity, high abundance and low material cost. Yet, the CZTSSe thin film solar cell has a low open-circuit voltage value that presents challenges. Herein, using GeSe2 as a new Ge source material, we have achieved a wider band gap CZTSSe-based semiconductor absorber layer with its band-gap controlled by adjusting the ratio of SnS2 : GeSe2 used. In addition, the Cu2Zn(Sn,Ge)(S,Se)4 thin films were prepared with optimal Ge doping (30%) and solar cells were fabricated to attain a respectable power conversion efficiency of 4.8% under 1.5 AM with an active area of 0.19 cm2 without an anti-reflection layer.Cu2ZnSn(S,Se)4 (CZTSSe) semiconductors have been a focus of extensive research effort owing to low-toxicity, high abundance and low material cost. Yet, the CZTSSe thin film solar cell has a low open-circuit voltage value that presents challenges. Herein, using GeSe2 as a new Ge source material, we have achieved a wider band gap CZTSSe-based semiconductor absorber layer with its band-gap controlled by adjusting the ratio of SnS2 : GeSe2 used. In addition, the Cu2Zn(Sn,Ge)(S,Se)4 thin films were prepared with optimal Ge doping (30%) and solar cells were fabricated to attain a respectable power conversion efficiency of 4.8% under 1.5 AM with an active area of 0.19 cm2 without an anti-reflection layer. Electronic supplementary information (ESI) available: The XRD patterns, chemical component analysis, top-view and cross-sectional images, and XPS of CZTGSSe thin films with different Ge content are exhibited. See DOI: 10.1039/c6nr00959j

  9. Can user testing of a clinical trial patient information sheet make it fit-for-purpose? - a randomized controlled trial

    PubMed Central

    2011-01-01

    Background The participant information sheet (PIS) provided to potential trial participants is a critical part of the process of valid consent. However, there is long-standing concern that these lengthy and complex documents are not fit-for-purpose. This has been supported recently through the application of a performance-based approach to testing and improving readability called user testing. This method is now widely used to improve patient medicine leaflets - determining whether people can find and understand key facts. This study applied for the first time a controlled design to determine whether a PIS developed through user testing had improved readability over the original, using a sheet from a UK trial in acute myeloid leukemia (AML16). Methods In the first phase the performance of the original PIS was tested on people in the target group for the trial. There were three rounds of testing including 50 people in total - with the information revised according to its performance after each of the first 2 rounds. In the second phase, the revised PIS was compared with the original in a parallel groups randomised controlled trial (RCT) A total of 123 participants were recruited and randomly allocated to read one version of the PIS to find and show understanding of 21 key facts. Results The first, developmental phase produced a revised PIS significantly altered in its wording and layout. In the second, trial phase 66% of participants who read the revised PIS were able to show understanding of all aspects of the trial, compared with 15% of those reading the original version (Odds Ratio 11.2; Chi-square = 31.5 p < .001). When asked to state a preference, 87.1% participants chose the revised PIS (Sign test p < .001). Conclusions The original PIS for the AML16 trial may not have enabled valid consent. Combining performance-based user testing with expertise in writing for patients and information design led to a significantly improved and preferred information sheet

  10. Electrostatic versus Electrochemical Doping and Control of Ferromagnetism in Ion-Gel-Gated Ultrathin La0.5Sr0.5CoO3-δ.

    PubMed

    Walter, Jeff; Wang, Helin; Luo, Bing; Frisbie, C Daniel; Leighton, Chris

    2016-08-23

    Recently, electrolyte gating techniques employing ionic liquids/gels in electric double layer transistors have proven remarkably effective in tuning charge carrier density in a variety of materials. The ability to control surface carrier densities at levels above 10(14) cm(-2) has led to widespread use in the study of superconductivity, insulator-metal transitions, etc. In many cases, controversy remains over the doping mechanism, however (i.e., electrostatic vs electrochemical (e.g., redox-based)), and the technique has been less applied to magnetic materials. Here, we discuss ion gel gating of nanoscale 8-unit-cell-thick hole-doped La0.5Sr0.5CoO3-δ (LSCO) films, probing in detail the critical bias windows and doping mechanisms. The LSCO films, which are under compressive stress on LaAlO3(001) substrates, are metallic and ferromagnetic (Curie temperature, TC ∼ 170 K), with strong anomalous Hall effect and perpendicular magnetic anisotropy. Transport measurements reveal that negative gate biases lead to reversible hole accumulation (i.e., predominantly electrostatic operation) up to some threshold, whereas positive bias immediately induces irreversibility. Experiments in inert/O2 atmospheres directly implicate oxygen vacancies in this irreversibility, supported by atomic force microscopy and X-ray photoelectron spectroscopy. The results are thus of general importance, suggesting that hole- and electron-doped oxides may respond very differently to electrolyte gating. Reversible voltage control of electronic/magnetic properties is then demonstrated under hole accumulation, including resistivity, magnetoresistance, and TC. The sizable anomalous Hall coefficient and perpendicular anisotropy in LSCO provide a particularly powerful probe of magnetism, enabling direct extraction of the voltage-dependent order parameter and TC shift. The latter amounts to ∼7%, with potential for much stronger modulation at lower Sr doping. PMID:27479878

  11. Controlled Doping of Vacancy-Containing Few-Layer MoS2 via Highly Stable Thiol-Based Molecular Chemisorption.

    PubMed

    Sim, Dong Min; Kim, Mincheol; Yim, Soonmin; Choi, Min-Jae; Choi, Jaesuk; Yoo, Seunghyup; Jung, Yeon Sik

    2015-12-22

    MoS2 is considered a promising two-dimensional active channel material for future nanoelectronics. However, the development of a facile, reliable, and controllable doping methodology is still critical for extending the applicability of MoS2. Here, we report surface charge transfer doping via thiol-based binding chemistry for modulating the electrical properties of vacancy-containing MoS2 (v-MoS2). Although vacancies present in 2D materials are generally regarded as undesirable components, we show that the electrical properties of MoS2 can be systematically engineered by exploiting the tight binding between the thiol group and sulfur vacancies and by choosing different functional groups. For example, we demonstrate that NH2-containing thiol molecules with lone electron pairs can serve as an n-dopant and achieve a substantial increase of electron density (Δn = 3.7 × 10(12) cm(-2)). On the other hand, fluorine-rich molecules can provide a p-doping effect (Δn = -7.0 × 10(11) cm(-2)) due to its high electronegativity. Moreover, the n- and p-doping effects were systematically evaluated by photoluminescence (PL), X-ray photoelectron spectroscopy (XPS), and electrical measurement results. The excellent binding stability of thiol molecules and recovery properties by thermal annealing will enable broader applicability of ultrathin MoS2 to various devices. PMID:26503105

  12. A fuzzy-logic based dual-purpose adaptive circuit for vibration control and energy harvesting using piezoelectric transducer

    NASA Astrophysics Data System (ADS)

    Liu, Zhe Peng; Li, Qing

    2013-04-01

    Due to their two-way electromechanical coupling effect, piezoelectric transducers can be used to synthesize passive vibration control schemes, e.g., RLC circuit with the integration of inductance and resistance elements that is conceptually similar to damped vibration absorber. Meanwhile, the wide usage of wireless sensors has led to the recent enthusiasm of developing piezoelectric-based energy harvesting devices that can convert ambient vibratory energy into useful electrical energy. It can be shown that the integration of circuitry elements such as resistance and inductance can benefit the energy harvesting capability. Here we explore a dual-purpose circuit that can facilitate simultaneous vibration suppression and energy harvesting. It is worth noting that the goal of vibration suppression and the goal of energy harvesting may not always complement each other. That is, the maximization of vibration suppression doesn't necessarily lead to the maximization of energy harvesting, and vice versa. In this research, we develop a fuzzy-logic based algorithm to decide the proper selection of circuitry elements to balance between the two goals. As the circuitry elements can be online tuned, this research yields an adaptive circuitry concept for the effective manipulation of system energy and vibration suppression. Comprehensive analyses are carried out to demonstrate the concept and operation.

  13. A controllable noise-like operation regime in a Yb-doped dispersion-mapped fiber ring laser

    NASA Astrophysics Data System (ADS)

    Zaytsev, A. K.; Lin, C. H.; You, Y. J.; Tsai, F. H.; Wang, C. L.; Pan, C. L.

    2013-04-01

    We report the generation of tunable high-energy noise-like pulses with a super-broadband spectrum from a Yb-doped dispersion-mapped fiber ring laser. Self-starting noise-like operation can be maintained over a relatively large range of pumping powers (4-13 W). The corresponding output power varies from 0.1 to 1.45 W. The maximum 3 dB spectral bandwidth of the noise-like pulses is about 48.2 nm while the output energy is as high as 47 nJ, limited by optical damage of the components. The central wavelength of the noise-like pulses can be tuned easily over ˜12 nm. The bandwidth and duration of the generated wave packets can also be controlled. The use of a negative dispersion-delay line and spectral filter are found to be important for generating such high-power noise-like operation. Experimental results are in good agreement with theoretical simulations.

  14. High dV/dt immunity MOS controlled thyristor using a double variable lateral doping technique for capacitor discharge applications

    NASA Astrophysics Data System (ADS)

    Chen, Wan-Jun; Sun, Rui-Ze; Peng, Chao-Fei; Zhang, Bo

    2014-07-01

    An analysis model of the dV/dt capability for a metal—oxide—semiconductor (MOS) controlled thyristor (MCT) is developed. It is shown that, in addition to the P-well resistance reported previously, the existence of the OFF-FET channel resistance in the MCT may degrade the dV/dt capability. Lower P-well and N-well dosages in the MCT are useful in getting a lower threshold voltage of OFF-FET and then a higher dV/dt immunity. However, both dosages are restricted by the requirements for the blocking property and the forward conduction capability. Thus, a double variable lateral doping (DVLD) technique is proposed to realize a high dV/dt immunity without any sacrifice in other properties. The accuracy of the developed model is verified by comparing the obtained results with those from simulations. In addition, this DVLD MCT features mask-saving compared with the conventional MCT fabrication process. The excellent device performance, coupled with the simple fabrication, makes the proposed DVLP MCT a promising candidate for capacitor discharge applications.

  15. Bichromatic coherent random lasing from dye-doped polymer stabilized blue phase liquid crystals controlled by pump light polarization

    NASA Astrophysics Data System (ADS)

    Wang, Lei; Wang, Meng; Yang, Mingchao; Shi, Li-Jie; Deng, Luogen; Yang, Huai

    2016-09-01

    In this paper, we investigate the bichromatic coherent random lasing actions from the dye-doped polymer stabilized blue phase liquid crystals. Two groups of lasing peaks, of which the full widith at half maximum is about 0.3 nm, are clearly observed. The shorter- and longer-wavelength modes are associated with the excitation of the single laser dye (DCM) monomers and dimers respectively. The experimental results show that the competition between the two groups of the lasing peaks can be controlled by varying the polarization of the pump light. When the polarization of the pump light is rotated from 0° to 90°, the intensity of the shorter-wavelength lasing peak group reduces while the intensity of the longer-wavelength lasing peak group increases. In addition, a red shift of the longer-wavelength modes is also observed and the physical mechanisms behind the red-shift phenomenon are discussed. Project supported by the National Natural Science Foundation of China (Grant Nos. 11474021 and 51333001), the Key Program for International S&T Cooperation Projects of China (Grant No. 2013DFB50340), the Issues of Priority Development Areas of the Research Fund for the Doctoral Program of Higher Education of China (Grant No. 20120001130005), and the Key (Key Grant) Project of Chinese Ministry of Education (Grant No. 313002).

  16. Bichromatic coherent random lasing from dye-doped polymer stabilized blue phase liquid crystals controlled by pump light polarization

    NASA Astrophysics Data System (ADS)

    Wang, Lei; Wang, Meng; Yang, Mingchao; Shi, Li-Jie; Deng, Luogen; Yang, Huai

    2016-09-01

    In this paper, we investigate the bichromatic coherent random lasing actions from the dye-doped polymer stabilized blue phase liquid crystals. Two groups of lasing peaks, of which the full widith at half maximum is about 0.3 nm, are clearly observed. The shorter- and longer-wavelength modes are associated with the excitation of the single laser dye (DCM) monomers and dimers respectively. The experimental results show that the competition between the two groups of the lasing peaks can be controlled by varying the polarization of the pump light. When the polarization of the pump light is rotated from 0° to 90°, the intensity of the shorter-wavelength lasing peak group reduces while the intensity of the longer-wavelength lasing peak group increases. In addition, a red shift of the longer-wavelength modes is also observed and the physical mechanisms behind the red-shift phenomenon are discussed. Project supported by the National Natural Science Foundation of China (Grant Nos. 11474021 and 51333001), the Key Program for International S&T Cooperation Projects of China (Grant No. 2013DFB50340), the Issues of Priority Development Areas of the Research Fund for the Doctoral Program of Higher Education of China (Grant No. 20120001130005), and the Key (Key Grant) Project of Chinese Ministry of Education (Grant No. 313002).

  17. Airplane dopes and doping

    NASA Technical Reports Server (NTRS)

    Smith, W H

    1919-01-01

    Cellulose acetate and cellulose nitrate are the important constituents of airplane dopes in use at the present time, but planes were treated with other materials in the experimental stages of flying. The above compounds belong to the class of colloids and are of value because they produce a shrinking action on the fabric when drying out of solution, rendering it drum tight. Other colloids possessing the same property have been proposed and tried. In the first stages of the development of dope, however, shrinkage was not considered. The fabric was treated merely to render it waterproof. The first airplanes constructed were covered with cotton fabric stretched as tightly as possible over the winds, fuselage, etc., and flying was possible only in fine weather. The necessity of an airplane which would fly under all weather conditions at once became apparent. Then followed experiments with rubberized fabrics, fabrics treated with glue rendered insoluble by formaldehyde or bichromate, fabrics treated with drying and nondrying oils, shellac, casein, etc. It was found that fabrics treated as above lost their tension in damp weather, and the oil from the motor penetrated the proofing material and weakened the fabric. For the most part the film of material lacked durability. Cellulose nitrate lacquers, however were found to be more satisfactory under varying weather conditions, added less weight to the planes, and were easily applied. On the other hand, they were highly inflammable, and oil from the motor penetrated the film of cellulose nitrate, causing the tension of the fabric to be relaxed.

  18. Enhanced room temperature ferromagnetism in electrodeposited Co-doped ZnO nanostructured thin films by controlling the oxygen vacancy defects

    SciTech Connect

    Simimol, A.; Anappara, Aji A.; Greulich-Weber, S.; Chowdhury, Prasanta; Barshilia, Harish C.

    2015-06-07

    We report the growth of un-doped and cobalt doped ZnO nanostructures fabricated on FTO coated glass substrates using electrodeposition method. A detailed study on the effects of dopant concentration on morphology, structural, optical, and magnetic properties of the ZnO nanostructures has been carried out systematically by varying the Co concentration (c.{sub Co}) from 0.01 to 1 mM. For c.{sub Co }≤ 0.2 mM, h-wurtzite phase with no secondary phases of Co were present in the ZnO nanostructures. For c.{sub Co} ≤ 0.2 mM, the photoluminescence spectra exhibited a decrease in the intensity of ultraviolet emission as well as band-gap narrowing with an increase in dopant concentration. All the doped samples displayed a broad emission in the visible range and its intensity increased with an increase in Co concentration. It was found that the defect centers such as oxygen vacancies and zinc interstitials were the source of the visible emission. The X-ray photoelectron spectroscopy studies revealed, Co was primarily in the divalent state, replacing the Zn ion inside the tetrahedral crystal site of ZnO without forming any cluster or secondary phases of Co. The un-doped ZnO nanorods exhibited diamagnetic behavior and it remained up to a c.{sub Co} of 0.05 mM, while for c.{sub Co }> 0.05 mM, the ZnO nanostructures exhibited ferromagnetic behavior at room temperature. The coercivity increased to 695 G for 0.2 mM Co-doped sample and then it decreased for c.{sub Co }> 0.2 mM. Our results illustrate that up to a threshold concentration of 0.2 mM, the strong ferromagnetism is due to the oxygen vacancy defects centers, which exist in the Co-doped ZnO nanostructures. The origin of strong ferromagnetism at room temperature in Co-doped ZnO nanostructures is attributed to the s-d exchange interaction between the localized spin moments resulting from the oxygen vacancies and d electrons of Co{sup 2+} ions. Our findings provide a new insight for tuning the

  19. Fit-for-purpose chromatographic method for the determination of amikacin in human plasma for the dosage control of patients.

    PubMed

    Ezquer-Garin, C; Escuder-Gilabert, L; Martín-Biosca, Y; Lisart, R Ferriols; Sagrado, S; Medina-Hernández, M J

    2016-04-01

    In this paper, a simple, rapid and sensitive method based on liquid chromatography with fluorimetric detection (HPLC-FLD) for the determination of amikacin (AMK) in human plasma is developed. Determination is performed by pre-column derivatization of AMK with ortho-phtalaldehyde (OPA) in presence of N-acetyl-L-cysteine (NAC) at pH 9.5 for 5 min at 80 °C. In our knowledge, this is the first time that NAC has been used in AMK derivatization. Derivatization conditions (pH, AMK/OPA/NAC molar ratios, temperature and reaction time) are optimized to obtain a single and stable, at room temperature, derivative. Separation of the derivative is achieved on a reversed phase LC column (Kromasil C18, 5 μm, 150 × 4.6 i.d. mm) with a mobile phase of 0.05 M phosphate buffer:acetonitrile (80:20, v/v) pumped at flow rate of 1.0 mL/min. Detection is performed using 337 and 439 nm for excitation and emission wavelengths, respectively. The method is fitted for the purpose of being a competitive alternative to the currently used method in many hospitals for AMK dosage control: fluorescence polarization immunoassay (FPIA). The method exhibits linearity in the 0.17-10 µg mL(-1) concentration range with a squared correlation coefficient higher than 0.995. Trueness and intermediate precision are estimated using spiked drug free plasma samples, which fulfill current UNE-EN ISO15189:2007 accreditation schemes. Finally, for the first time, statistical comparison against the FPIA method is demonstrated using plasma samples from 31 patients under treatment with AMK.

  20. Gain-controlled erbium-doped fiber amplifier using mode-selective photonic lantern

    NASA Astrophysics Data System (ADS)

    Lopez-Galmiche, G.; Sanjabi Eznaveh, Z.; Antonio-Lopez, J. E.; Velazquez-Benitez, A. M.; Rodriguez-Asomoza, J.; Herrera-Piad, L. A.; Sanchez-Mondragon, J. J.; Gonent, C.; Sillard, P.; Li, G.; SchuÌlzgen, A.; Okonkwo, C.; Amezcua Correa, R.

    2016-02-01

    For the first time, we demonstrate the implementation of a core pumped few mode erbium amplifier utilizing a mode selective photonic lantern for spatial modal control of the pump light. This device is able to individually amplify the first six fiber modes with low differential modal gain. In addition, we obtained differential modal gain lower than 1 dB and signal gain of approximately 16.17 dB at λs = 1550 nm through forward pumping the LP21 modes at λp = 976 nm.

  1. Structure and mechanism of formation of an important ion in doping control

    NASA Astrophysics Data System (ADS)

    Borges, Chad R.; Taccogno, James; Crouch, Dennis J.; Le, Ly; Truong, Thanh N.

    2005-12-01

    An ion with m/z 143 serves as a biomarker that is often continuously monitored in urine samples undergoing screening by electron ionization gas chromatography/mass spectrometry (EI GC/MS) for banned anabolic agents. The ion is known to arise from trimethylsilyl (TMS)-derivatized synthetic 17-hydroxy, 17-methyl steroids. The purpose of this work was to characterize, in detail, the origin(s), structure(s), and mechanism(s) of formation of such ions with m/z 143. High resolution mass spectrometry (HRMS) data revealed the elemental composition of the D-ring derived m/z 143 ion to be C7H15OSi. Analysis of dihydrotestosterone (DHT) and its 2-methyl substituted analog dromostanolone by HRMS revealed that an elementally equivalent ion of m/z 143 could be derived from the A-ring of TMS-derivatized 3-keto-enol steroids demonstrating that an abnormally intense peak in the m/z 143 extracted ion chromatogram of urine samples undergoing screening for banned anabolic agents does not necessarily indicate the presence of a 17-hydroxy, 17-methyl steroid. To gain information on ion structure, breakdown curves for the most abundant product ions of the m/z 143 ion were generated using both native and perdeutero-TMS derivatives, providing structures for second, third, and fourth generation product ions. An EI-mass spectrum of [16,16,17-2H3]-DHT (DHT-d3) demonstrated that one of the C-16 hydrogen atoms is removed prior to the formation of an ion that is highly analogous to the ion with m/z 143 strongly suggesting, in accord with all other evidence, one particular fragmentation pathway and resulting product: a resonance stabilized 3-(O-trimethylsilyl)but-1-ene ion.

  2. Morphology Control of Metal-Organic Frameworks Based on Paddle-Wheel Units on Ion-Doped Polymer Substrate Using an Interfacial Growth Approach.

    PubMed

    Tsuruoka, Takaaki; Mantani, Koji; Miyanaga, Ayumi; Matsuyama, Tetsuhiro; Ohhashi, Takashi; Takashima, Yohei; Akamatsu, Kensuke

    2016-06-21

    A three-dimensional metal-organic framework (MOF) consisting of pillared square-grid nets based on paddle-wheel units was synthesized by interfacial self-assembly of the frameworks on a metal-ion-doped polymer substrate. Although this type of Cu-based MOF is typically synthesized by a two-step solvothermal method, the utilization of a metal-ion-doped polymer substrate as a metal source for the framework allowed for the one-pot growth of MOF crystals on the substrate. The morphology of the obtained MOF crystals could be controlled from tetragonal to elongated tetragonal with different aspect ratios by changing the concentrations of the dicarboxylate layer ligands and diamine pillar ligands. The present approach provides a new route for the design and synthesis of MOF crystals and thin films for future applications such as gas membranes, catalysts, and electronic devices. PMID:27243413

  3. Large-scale and controllable synthesis of metal-free nitrogen-doped carbon nanofibers and nanocoils over water-soluble Na2CO3

    PubMed Central

    2013-01-01

    Using acetylene as carbon source, ammonia as nitrogen source, and Na2CO3 powder as catalyst, we synthesized nitrogen-doped carbon nanofibers (N-CNFs) and carbon nanocoils (N-CNCs) selectively at 450°C and 500°C, respectively. The water-soluble Na2CO3 is removed through simple washing with water and the nitrogen-doped carbon nanomaterials can be collected in high purity. The approach is simple, inexpensive, and environment-benign; it can be used for controlled production of N-CNFs or N-CNCs. We report the role of catalyst, the effect of pyrolysis temperature, and the photoluminescence properties of the as-harvested N-CNFs and N-CNCs. PMID:24369821

  4. Neutron transmutation doped Ge bolometers

    NASA Technical Reports Server (NTRS)

    Haller, E. E.; Kreysa, E.; Palaio, N. P.; Richards, P. L.; Rodder, M.

    1983-01-01

    Some conclusions reached are as follow. Neutron Transmutation Doping (NTD) of high quality Ge single crystals provides perfect control of doping concentration and uniformity. The resistivity can be tailored to any given bolometer operating temperature down to 0.1 K and probably lower. The excellent uniformity is advantaged for detector array development.

  5. Optimizing the Binding Energy of Hydrogen on Nanostructured Carbon Materials through Structure Control and Chemical Doping

    SciTech Connect

    Jie Liu

    2011-02-01

    The DOE Hydrogen Sorption Center of Excellence (HSCoE) was formed in 2005 to develop materials for hydrogen storage systems to be used in light-duty vehicles. The HSCoE and two related centers of excellence were created as follow-on activities to the DOE Office of Energy Efficiency and Renewable Energy’s (EERE’s) Hydrogen Storage Grand Challenge Solicitation issued in FY 2003. The Hydrogen Sorption Center of Excellence (HSCoE) focuses on developing high-capacity sorbents with the goal to operate at temperatures and pressures approaching ambient and be efficiently and quickly charged in the tank with minimal energy requirements and penalties to the hydrogen fuel infrastructure. The work was directed at overcoming barriers to achieving DOE system goals and identifying pathways to meet the hydrogen storage system targets. To ensure that the development activities were performed as efficiently as possible, the HSCoE formed complementary, focused development clusters based on the following four sorption-based hydrogen storage mechanisms: 1. Physisorption on high specific surface area and nominally single element materials 2. Enhanced H2 binding in Substituted/heterogeneous materials 3. Strong and/or multiple H2 binding from coordinated but electronically unsatruated metal centers 4. Weak Chemisorption/Spillover. As a member of the team, our group at Duke studied the synthesis of various carbon-based materials, including carbon nanotubes and microporous carbon materials with controlled porosity. We worked closely with other team members to study the effect of pore size on the binding energy of hydrogen to the carbon –based materials. Our initial project focus was on the synthesis and purification of small diameter, single-walled carbon nanotubes (SWNTs) with well-controlled diameters for the study of their hydrogen storage properties as a function of diameters. We developed a chemical vapor deposition method that synthesized gram quantities of carbon nanotubes with

  6. Controllable Synthesis of Monodisperse Er3+-Doped Lanthanide Oxyfluorides Nanocrystals with Intense Mid-Infrared Emission

    NASA Astrophysics Data System (ADS)

    He, Huilin; Liu, Qiang; Yang, Dandan; Pan, Qiwen; Qiu, Jianrong; Dong, Guoping

    2016-10-01

    Monodisperse lanthanide oxyfluorides LnOF (Ln = Gd, Y) with mid-infrared emissions were controllably synthesized via a mild co-precipitation route and a subsequent heat-treatment. The detailed composition and morphology were characterized by X-ray diffraction (XRD), scanning electron microscope (SEM) and high resolution transmission electron microscopy (HRTEM). The results showed that monodisperse GdOF:Er3+ were nano-riced shape with length about 350 nm and width about 120 nm, while the quasi-spherical YOF:Er3+ were uniform nanocrystals with an average size around 100 nm. The influence of calcination temperature on the size and phase transition of LnOF nanocrystals was also investigated. The photoluminescence (PL) spectra indicated that the 2.7 μm emission of Er3+ had achieved in both GdOF and YOF nanocrystals, which were calcined at different temperatures. In addition, the decay time of both 4I13/2 and 4I13/2 energy levels corresponding to Er3+ in YOF nanocrystals were also studied in detail. The results suggested that both rice-shaped GdOF nanocrystals and YOF nanocrystals could provide suitable candidate materials for nanocrystals-glass composites, which could be a step forward to the realization of mid-infrared laser materials.

  7. Optically controlled spin-polarization memory effect on Mn delta-doped heterostructures

    PubMed Central

    Balanta, M. A. G.; Brasil, M. J. S. P.; Iikawa, F.; Mendes, Udson C.; Brum, J. A.; Danilov, Yu. A.; Dorokhin, M. V.; Vikhrova, O. V.; Zvonkov, B. N.

    2016-01-01

    We investigated the dynamics of the interaction between spin-polarized photo-created carriers and Mn ions on InGaAs/GaAs: Mn structures. The carriers are confined in an InGaAs quantum well and the Mn ions come from a Mn delta-layer grown at the GaAs barrier close to the well. Even though the carriers and the Mn ions are spatially separated, the interaction between them is demonstrated by time-resolved spin-polarized photoluminescence measurements. Using a pre-pulse laser excitation with an opposite circular-polarization clearly reduces the polarization degree of the quantum-well emission for samples where a strong magnetic interaction is observed. The results demonstrate that the Mn ions act as a spin-memory that can be optically controlled by the polarization of the photocreated carriers. On the other hand, the spin-polarized Mn ions also affect the spin-polarization of the subsequently created carriers as observed by their spin relaxation time. These effects fade away with increasing time delays between the pulses as well as with increasing temperatures. PMID:27080310

  8. Erbium-doped slot waveguides containing size-controlled silicon nanocrystals

    SciTech Connect

    Hoffmann, R.; Beyer, J. Heitmann, J.; Klemm, V.; Rafaja, D.; Johnson, B. C.; McCallum, J. C.

    2015-04-28

    Silicon based slot waveguides with a slot containing Si nanocrystals (Si-nc) and Erbium ions (Er{sup 3+}) inside a silica matrix were prepared using sputter deposition and low-energy ion implantation. This sequence enabled independent optimization of nanocrystal formation and Er{sup 3+} incorporation parameters. Using a superlattice approach, the size of the Si-nc inside the slot could be controlled and optimized for maximum Er{sup 3+} luminescence yield at 1.54 μm. Er{sup 3+} is found to be efficiently pumped by Si-nc of sizes around 3 to 4 nm. Increasing Er{sup 3+} photoluminescence at 1.54 μm with increasing post-implantation annealing temperatures up to 1000 °C is attributed to annealing of matrix or Si-nc interface defects mainly. Additionally, a dependence of the Er{sup 3+} luminescence intensity on both the excitation and emission linear polarization orientation is shown, which demonstrates efficient field enhancement in sputtered slot waveguide structures.

  9. Controllable Synthesis of Monodisperse Er3+-Doped Lanthanide Oxyfluorides Nanocrystals with Intense Mid-Infrared Emission

    PubMed Central

    He, Huilin; Liu, Qiang; Yang, Dandan; Pan, Qiwen; Qiu, Jianrong; Dong, Guoping

    2016-01-01

    Monodisperse lanthanide oxyfluorides LnOF (Ln = Gd, Y) with mid-infrared emissions were controllably synthesized via a mild co-precipitation route and a subsequent heat-treatment. The detailed composition and morphology were characterized by X-ray diffraction (XRD), scanning electron microscope (SEM) and high resolution transmission electron microscopy (HRTEM). The results showed that monodisperse GdOF:Er3+ were nano-riced shape with length about 350 nm and width about 120 nm, while the quasi-spherical YOF:Er3+ were uniform nanocrystals with an average size around 100 nm. The influence of calcination temperature on the size and phase transition of LnOF nanocrystals was also investigated. The photoluminescence (PL) spectra indicated that the 2.7 μm emission of Er3+ had achieved in both GdOF and YOF nanocrystals, which were calcined at different temperatures. In addition, the decay time of both 4I13/2 and 4I13/2 energy levels corresponding to Er3+ in YOF nanocrystals were also studied in detail. The results suggested that both rice-shaped GdOF nanocrystals and YOF nanocrystals could provide suitable candidate materials for nanocrystals-glass composites, which could be a step forward to the realization of mid-infrared laser materials. PMID:27748411

  10. Graphene coated with controllable N-doped carbon layer by molecular layer deposition as electrode materials for supercapacitors

    NASA Astrophysics Data System (ADS)

    Chen, Yao; Gao, Zhe; Zhang, Bin; Zhao, Shichao; Qin, Yong

    2016-05-01

    In this work, graphene is coated with nitrogen-doped carbon layer, which is produced by a carbonization process of aromatic polyimide (PI) films deposited on the surfaces of graphene by molecular layer deposition (MLD). The utilization of MLD not only allows uniform coating of PI layers on the surfaces of pristine graphene without any surface treatment, but also enables homogenous dispersion of doped nitrogen atoms in the carbonized products. The as-prepared N-doped carbon layer coated graphene (NC-G) exhibited remarkable capacitance performance as electrode materials for supercapacitor, showing a high specific capacitance of 290.2 F g-1 at current density of 1 A g-1 in 6 M KOH aqueous electrolyte, meanwhile maintaining good rate performance and stable cycle capability. The NC-G synthesized by this way represents an alternative promising candidate as electrode material for supercapacitors.

  11. Shape-controlled synthesis of Sn-doped CuO nanoparticles for catalytic degradation of Rhodamine B.

    PubMed

    Vomáčka, Petr; Štengl, Václav; Henych, Jiří; Kormunda, Martin

    2016-11-01

    The uniform Sn-doped CuO nanoparticles were synthesized by a simple solution method at a low temperature. The prepared samples were investigated by X-ray diffraction (XRD), X-ray photoelectron spectroscopy (XPS), electron microscopy techniques (HRSEM, HRTEM, SAED, STEM and EDS elemental mapping), atomic force microscopy (AFM), UV/Vis spectroscopy, nitrogen physisorption (BET) and by evaluation of the catalytic activity on the degradation of Rhodamine B. The tin doping had a considerable influence on the morphology of CuO. The gradual narrowing of the particles morphology in the crystallographic [010] direction was observed with increasing the dopant concentration. The plate-like, rectangularsquare and rod-like CuO nanoparticles were obtained. The mechanism of a crystal growth of CuO associated with doping is proposed. The tin doping also affected the structural and optical properties of CuO. Increasing the amount of a dopant led to a red-shift of a band gap from 1.33 to 1.18eV. The incorporation of tin into the structure of copper oxide was confirmed by XRD and distribution of tin mapped by EDS analysis. The good catalytic properties of the as-prepared doped material were demonstrated by the enhanced catalytic removal of Rhodamine B in the presence of H2O2. The undoped CuO nanosheets reached only 24% efficiency in the removal of Rhodamine B within two hours. The best result exhibited CuO_050Sn sample containing 4at.% of tin and the degradation of Rhodamine B reached 99% within the same time. We have demonstrated a simple, scalable process for the preparation of catalytically very active Sn-doped CuO nanoparticles with varying properties. PMID:27450889

  12. Synthesis and controllable oxidation of monodisperse cobalt-doped wüstite nanoparticles and their core-shell stability and exchange-bias stabilization.

    PubMed

    Chen, Chih-Jung; Chiang, Ray-Kuang; Kamali, Saeed; Wang, Sue-Lein

    2015-09-14

    Cobalt-doped wüstite (CWT), Co0.33Fe0.67O, nanoparticles were prepared via the thermal decomposition of CoFe2-oleate complexes in organic solvents. A controllable oxidation process was then performed to obtain Co0.33Fe0.67O/CoFe2O4 core-shell structures with different core-to-shell volume ratios and exchange bias properties. The oxidized core-shell samples with a ∼4 nm CoFe2O4 shell showed good resistance to oxygen transmission. Thus, it is inferred that the cobalt ferrite shell provides a better oxidation barrier performance than magnetite in the un-doped case. The hysteresis loops of the oxidized 19 nm samples exhibited a high exchange bias field (H(E)), an enhanced coercivity field (H(C)), and a pronounced vertical shift, thus indicating the presence of a strong exchange bias coupling effect. More importantly, the onset temperature of H(E) was found to be higher than 200 K, which suggests that cobalt doping increases the Néel temperature (T(N)) of the CWT core. In general, the results show that the homogeneous dispersion of Co in iron precursors improves the stability of the final CWT nanoparticles. Moreover, the CoFe2O4 shells formed following oxidation increase the oxidation resistance of the CWT cores and enhance their anisotropy energy.

  13. Synthesis and controllable oxidation of monodisperse cobalt-doped wüstite nanoparticles and their core-shell stability and exchange-bias stabilization.

    PubMed

    Chen, Chih-Jung; Chiang, Ray-Kuang; Kamali, Saeed; Wang, Sue-Lein

    2015-09-14

    Cobalt-doped wüstite (CWT), Co0.33Fe0.67O, nanoparticles were prepared via the thermal decomposition of CoFe2-oleate complexes in organic solvents. A controllable oxidation process was then performed to obtain Co0.33Fe0.67O/CoFe2O4 core-shell structures with different core-to-shell volume ratios and exchange bias properties. The oxidized core-shell samples with a ∼4 nm CoFe2O4 shell showed good resistance to oxygen transmission. Thus, it is inferred that the cobalt ferrite shell provides a better oxidation barrier performance than magnetite in the un-doped case. The hysteresis loops of the oxidized 19 nm samples exhibited a high exchange bias field (H(E)), an enhanced coercivity field (H(C)), and a pronounced vertical shift, thus indicating the presence of a strong exchange bias coupling effect. More importantly, the onset temperature of H(E) was found to be higher than 200 K, which suggests that cobalt doping increases the Néel temperature (T(N)) of the CWT core. In general, the results show that the homogeneous dispersion of Co in iron precursors improves the stability of the final CWT nanoparticles. Moreover, the CoFe2O4 shells formed following oxidation increase the oxidation resistance of the CWT cores and enhance their anisotropy energy. PMID:26243163

  14. Precise control of photoluminescence of silicon-vacancy color centers in homoepitaxial single-crystal diamond: evaluation of efficiency of Si doping from gas phase

    NASA Astrophysics Data System (ADS)

    Ralchenko, Victor; Sedov, Vadim; Saraykin, Vladimir; Bolshakov, Andrey; Zavedeev, Evgeny; Ashkinazi, Evgeny; Khomich, Andrew

    2016-09-01

    Ability to precisely control the Si-related color center abundance in diamond is important for the use of silicon-vacancy (SiV) defects with bright photoluminescence (PL) in quantum information technologies and optical biomarkers. Here, we evaluated the efficiency of Si incorporation in (100) plane of homoepitaxial diamond layers upon in situ doping by adding silane SiH4 in the course of diamond chemical vapor deposition in microwave plasma using CH4-H2 mixtures. Both the Si concentration in the doped samples, as determined by secondary ion mass spectrometry, and PL intensity of SiV centers at 738 nm wavelength, measured at excitation wavelength of 473 nm, demonstrate a linear increase with silane content in feed gas in the range. The incorporation efficiency f, defined as the ratio of Si concentration in diamond to that in gas, f = [Si/C]dia/[Si/C]gas is found to be (1.1 ± 0.5) × 10-3 for the silane concentrations explored, [SiH4/CH4] < 0.7 %; thus, the Si atoms are accommodated in (100) diamond face easier than nitrogen and phosphorus, but more difficult than boron. This finding allows a tailoring of the Si content and photoluminescence intensity of SiV centers in in situ doped CVD diamond.

  15. Convenient and controllable preparation of a novel uniformly nitrogen doped porous graphene/Pt nanoflower material and its highly-efficient electrochemical biosensing.

    PubMed

    Ren, Shuang; Wang, Huan; Zhang, Yufan; Sun, Yuena; Li, Lanfen; Zhang, Hongyi; Shi, Zhihong; Li, Mingjie; Li, Meng

    2016-04-25

    By employing dopamine as a nitrogen source and reducing agent, the block copolymer P123 as a pore forming agent, and graphene oxide as a carbon precursor, we present, for the first time, a convenient and controllable approach to the preparation of a novel uniformly nitrogen doped porous graphene (N-PGR) material. Using the prepared N-PGR as the supporting material, a novel nitrogen doped porous graphene/Pt nanoflower material (Pt/N-PGR) was obtained by a green and simple method. The characterization results of scanning electron microscopy (SEM), element mapping, transmission electron microscopy (TEM) and X-ray photoelectron spectroscopy (XPS) demonstrate that Pt nanoflowers are uniformly dispersed on nitrogen doped porous graphene. Electrochemical measurements show that Pt/N-PGR-900/GCE exhibits improved electrocatalytic activity towards H2O2 reduction and glucose oxidation. Linear responses are found for H2O2 and glucose in the range of 0.5-40 326 μM and 0.5-133.5 mM with the detection limit (S/N = 3) of 0.2 μM and 0.05 mM, respectively. In addition, Pt/N-PGR-900/GCE exhibits high sensitivity and good anti-interference ability. The superior catalytic activity and selectivity make Pt/N-PGR a promising nanomaterial for application in electrochemical biosensing studies.

  16. Controllable nitrogen doping in as deposited TiO{sub 2} film and its effect on post deposition annealing

    SciTech Connect

    Deng, Shaoren; Devloo-Casier, Kilian; Devulder, Wouter; Dendooven, Jolien; Deduytsche, Davy; Detavernier, Christophe; Lenaerts, Silvia; Martens, Johan A.; Van den Berghe, Sven

    2014-01-15

    In order to narrow the band gap of TiO{sub 2}, nitrogen doping by combining thermal atomic layer deposition (TALD) of TiO{sub 2} and plasma enhanced atomic layer deposition (PEALD) of TiN has been implemented. By altering the ratio between TALD TiO{sub 2} and PEALD TiN, the as synthesized TiO{sub x}N{sub y} films showed different band gaps (from 1.91 eV to 3.14 eV). In situ x-ray diffraction characterization showed that the crystallization behavior of these films changed after nitrogen doping. After annealing in helium, nitrogen doped TiO{sub 2} films crystallized into rutile phase while for the samples annealed in air a preferential growth of the anatase TiO{sub 2} along (001) orientation was observed. Photocatalytic tests of the degradation of stearic acid were done to evaluate the effect of N doping on the photocatalytic activity.

  17. En route to controlled catalytic CVD synthesis of densely packed and vertically aligned nitrogen-doped carbon nanotube arrays.

    PubMed

    Boncel, Slawomir; Pattinson, Sebastian W; Geiser, Valérie; Shaffer, Milo S P; Koziol, Krzysztof K K

    2014-01-01

    The catalytic chemical vapour deposition (c-CVD) technique was applied in the synthesis of vertically aligned arrays of nitrogen-doped carbon nanotubes (N-CNTs). A mixture of toluene (main carbon source), pyrazine (1,4-diazine, nitrogen source) and ferrocene (catalyst precursor) was used as the injection feedstock. To optimize conditions for growing the most dense and aligned N-CNT arrays, we investigated the influence of key parameters, i.e., growth temperature (660, 760 and 860 °C), composition of the feedstock and time of growth, on morphology and properties of N-CNTs. The presence of nitrogen species in the hot zone of the quartz reactor decreased the growth rate of N-CNTs down to about one twentieth compared to the growth rate of multi-wall CNTs (MWCNTs). As revealed by electron microscopy studies (SEM, TEM), the individual N-CNTs (half as thick as MWCNTs) grown under the optimal conditions were characterized by a superior straightness of the outer walls, which translated into a high alignment of dense nanotube arrays, i.e., 5 × 10(8) nanotubes per mm(2) (100 times more than for MWCNTs grown in the absence of nitrogen precursor). In turn, the internal crystallographic order of the N-CNTs was found to be of a 'bamboo'-like or 'membrane'-like (multi-compartmental structure) morphology. The nitrogen content in the nanotube products, which ranged from 0.0 to 3.0 wt %, was controlled through the concentration of pyrazine in the feedstock. Moreover, as revealed by Raman/FT-IR spectroscopy, the incorporation of nitrogen atoms into the nanotube walls was found to be proportional to the number of deviations from the sp(2)-hybridisation of graphene C-atoms. As studied by XRD, the temperature and the [pyrazine]/[ferrocene] ratio in the feedstock affected the composition of the catalyst particles, and hence changed the growth mechanism of individual N-CNTs into a 'mixed base-and-tip' (primarily of the base-type) type as compared to the purely 'base'-type for undoped

  18. En route to controlled catalytic CVD synthesis of densely packed and vertically aligned nitrogen-doped carbon nanotube arrays

    PubMed Central

    Pattinson, Sebastian W; Geiser, Valérie; Shaffer, Milo S P

    2014-01-01

    Summary The catalytic chemical vapour deposition (c-CVD) technique was applied in the synthesis of vertically aligned arrays of nitrogen-doped carbon nanotubes (N-CNTs). A mixture of toluene (main carbon source), pyrazine (1,4-diazine, nitrogen source) and ferrocene (catalyst precursor) was used as the injection feedstock. To optimize conditions for growing the most dense and aligned N-CNT arrays, we investigated the influence of key parameters, i.e., growth temperature (660, 760 and 860 °C), composition of the feedstock and time of growth, on morphology and properties of N-CNTs. The presence of nitrogen species in the hot zone of the quartz reactor decreased the growth rate of N-CNTs down to about one twentieth compared to the growth rate of multi-wall CNTs (MWCNTs). As revealed by electron microscopy studies (SEM, TEM), the individual N-CNTs (half as thick as MWCNTs) grown under the optimal conditions were characterized by a superior straightness of the outer walls, which translated into a high alignment of dense nanotube arrays, i.e., 5 × 108 nanotubes per mm2 (100 times more than for MWCNTs grown in the absence of nitrogen precursor). In turn, the internal crystallographic order of the N-CNTs was found to be of a ‘bamboo’-like or ‘membrane’-like (multi-compartmental structure) morphology. The nitrogen content in the nanotube products, which ranged from 0.0 to 3.0 wt %, was controlled through the concentration of pyrazine in the feedstock. Moreover, as revealed by Raman/FT-IR spectroscopy, the incorporation of nitrogen atoms into the nanotube walls was found to be proportional to the number of deviations from the sp2-hybridisation of graphene C-atoms. As studied by XRD, the temperature and the [pyrazine]/[ferrocene] ratio in the feedstock affected the composition of the catalyst particles, and hence changed the growth mechanism of individual N-CNTs into a ‘mixed base-and-tip’ (primarily of the base-type) type as compared to the purely

  19. En route to controlled catalytic CVD synthesis of densely packed and vertically aligned nitrogen-doped carbon nanotube arrays.

    PubMed

    Boncel, Slawomir; Pattinson, Sebastian W; Geiser, Valérie; Shaffer, Milo S P; Koziol, Krzysztof K K

    2014-01-01

    The catalytic chemical vapour deposition (c-CVD) technique was applied in the synthesis of vertically aligned arrays of nitrogen-doped carbon nanotubes (N-CNTs). A mixture of toluene (main carbon source), pyrazine (1,4-diazine, nitrogen source) and ferrocene (catalyst precursor) was used as the injection feedstock. To optimize conditions for growing the most dense and aligned N-CNT arrays, we investigated the influence of key parameters, i.e., growth temperature (660, 760 and 860 °C), composition of the feedstock and time of growth, on morphology and properties of N-CNTs. The presence of nitrogen species in the hot zone of the quartz reactor decreased the growth rate of N-CNTs down to about one twentieth compared to the growth rate of multi-wall CNTs (MWCNTs). As revealed by electron microscopy studies (SEM, TEM), the individual N-CNTs (half as thick as MWCNTs) grown under the optimal conditions were characterized by a superior straightness of the outer walls, which translated into a high alignment of dense nanotube arrays, i.e., 5 × 10(8) nanotubes per mm(2) (100 times more than for MWCNTs grown in the absence of nitrogen precursor). In turn, the internal crystallographic order of the N-CNTs was found to be of a 'bamboo'-like or 'membrane'-like (multi-compartmental structure) morphology. The nitrogen content in the nanotube products, which ranged from 0.0 to 3.0 wt %, was controlled through the concentration of pyrazine in the feedstock. Moreover, as revealed by Raman/FT-IR spectroscopy, the incorporation of nitrogen atoms into the nanotube walls was found to be proportional to the number of deviations from the sp(2)-hybridisation of graphene C-atoms. As studied by XRD, the temperature and the [pyrazine]/[ferrocene] ratio in the feedstock affected the composition of the catalyst particles, and hence changed the growth mechanism of individual N-CNTs into a 'mixed base-and-tip' (primarily of the base-type) type as compared to the purely 'base'-type for undoped

  20. Significant increase of salivary testosterone levels after single therapeutic transdermal administration of testosterone: suitability as a potential screening parameter in doping control.

    PubMed

    Thieme, Detlef; Rautenberg, Claudia; Grosse, Joachim; Schoenfelder, Martin

    2013-01-01

    The legally defensible proof of the abuse of endogenous steroids in sports is currently based on carbon isotope ratio mass spectrometry (IRMS), i.e. a comparison between (13)C/(12)C ratios of diagnostic precursors and metabolites of testosterone. The application of this technique requires a chromatographic baseline separation of respective steroids prior to IRMS detection and hence laborious sample pre-processing of the urinary steroid extracts including clean up by solid-phase extraction and/or liquid chromatography. Consequently, an efficient pre-selection of suspicious control urine samples is essential for appropriate follow up confirmation by IRMS and effective doping control. Two single transdermal administration studies of testosterone (50 mg Testogel® and Testopatch® at 3.8 mg in 16 h, respectively) were conducted and resulting profiles of salivary testosterone and urinary steroid profiles and corresponding carbon isotope ratios were determined. Conventional doping control markers (testosterone/epitestosterone ratio, threshold concentrations of androsterone, etiocholanolone, or androstanediols) did not approach or exceed critical thresholds. In contrast to these moderate variations, the testosterone concentration in oral fluid increased from basal values (30-142 pg/mg) to peak concentrations above 1000 pg/mg. It is likely that this significant increase in oral fluid is due to a pulsatile elevation of free (protein unbound) circulating testosterone after transdermal administration and may be assumed to represent a more diagnostic marker for transdermal testosterone administration.

  1. Design, Development, Validation, and Use of Synthetic Nucleic Acid Controls for Diagnostic Purposes and Application to Cystic Fibrosis Testing

    PubMed Central

    Christensen, Todd M.; Jama, Mohamed; Ponek, Victor; Lyon, Elaine; Wilson, Jean Amos; Hoffmann, Marcy L.; Bejjani, Bassem A.

    2007-01-01

    We have designed, tested, and validated synthetic DNA molecules that may be used as reference standard controls in the simultaneous detection of mutations in one or more genes. These controls consist of a mixture of oligonucleotides (100 to 120 bases long) each designed for the detection of one or more disease-causing mutation(s), depending on the proximity of the mutations to one another. Each control molecule is identical to 80 to 100 bases that span the targeted mutations. In addition, each oligonucleotide is tagged at the 5′ and 3′ ends with distinct nucleic acid sequences that allow for the design of complementary primers for polymerase chain reaction amplification. We designed the tags to amplify control molecules comprising 32 CFTR mutations, including the American College of Medical Genetics minimum carrier screening panel of 23, with one pair of primers in a single tube. We tested the performance of these controls on many platforms including the Applied Biosystems/Celera oligonucleotide ligation assay and the Tm Bioscience Tag-It platforms. All 32 mutations were detected consistently. This simple methodology allows for maximum flexibility and rapid implementation. It has not escaped our notice that the design of these molecules makes possible the production of similar controls for virtually any mutation or sequence of interest. PMID:17591930

  2. Nucleation, Growth Mechanism, and Controlled Coating of ZnO ALD onto Vertically Aligned N-Doped CNTs.

    PubMed

    Silva, R M; Ferro, M C; Araujo, J R; Achete, C A; Clavel, G; Silva, R F; Pinna, N

    2016-07-19

    Zinc oxide thin films were deposited on vertically aligned nitrogen-doped carbon nanotubes (N-CNTs) by atomic layer deposition (ALD) from diethylzinc and water. The study demonstrates that doping CNTs with nitrogen is an effective approach for the "activation" of the CNTs surface for the ALD of metal oxides. Conformal ZnO coatings are already obtained after 50 ALD cycles, whereas at lower ALD cycles an island growth mode is observed. Moreover, the process allows for a uniform growth from the top to the bottom of the vertically aligned N-CNT arrays. X-ray photoelectron spectroscopy demonstrates that ZnO nucleation takes place at the N-containing species on the surface of the CNTs by the formation of the Zn-N bonds at the interface between the CNTs and the ZnO film. PMID:27333190

  3. Nucleation, Growth Mechanism, and Controlled Coating of ZnO ALD onto Vertically Aligned N-Doped CNTs.

    PubMed

    Silva, R M; Ferro, M C; Araujo, J R; Achete, C A; Clavel, G; Silva, R F; Pinna, N

    2016-07-19

    Zinc oxide thin films were deposited on vertically aligned nitrogen-doped carbon nanotubes (N-CNTs) by atomic layer deposition (ALD) from diethylzinc and water. The study demonstrates that doping CNTs with nitrogen is an effective approach for the "activation" of the CNTs surface for the ALD of metal oxides. Conformal ZnO coatings are already obtained after 50 ALD cycles, whereas at lower ALD cycles an island growth mode is observed. Moreover, the process allows for a uniform growth from the top to the bottom of the vertically aligned N-CNT arrays. X-ray photoelectron spectroscopy demonstrates that ZnO nucleation takes place at the N-containing species on the surface of the CNTs by the formation of the Zn-N bonds at the interface between the CNTs and the ZnO film.

  4. Controlling polymorphic structures and investigating electric properties of Ca-doped zirconia using solid state ceramic method

    SciTech Connect

    Emam, W.I.; Mabied, Ahmed F.; Hashem, H.M.; Selim, M.M.; El-Shabiny, A.M.; Ahmed Farag, I.S.

    2015-08-15

    Structural study of Zr{sub 1−x}Ca{sub x}O{sub 2−x} samples with x=0.01–0.15 were prepared using solid state ceramic method. X-ray diffraction analysis revealed a mixture of the high temperature phase and the monoclinic one for the samples with x≤0.05. On the other hand, the formation of a single high temperature cubic phase was observed within a concentration range of x=0.06–0.10. At concentrations higher than 0.10 the calcium zirconate phase was observed besides the dominant high temperature one. Rietveld refinement of the single phase data clearly revealed, that substitution of zirconium by calcium increases both the lattice parameters as well as the tetrahedral bond length. Ionic to electronic conductivity ratio enhanced considerably as Ca-doping level ascends. The dielectric constant shows strong temperature dependence at lower frequencies. The dielectric loss factor increases rapidly with the increase in temperature at lower frequencies, while decreases with the increase in frequency at higher temperatures. The ionic conduction is considered as the dominant process at higher temperatures. - Graphical abstract: Forming a high temperature cubic zirconia phase at 1200 °C using ceramic solid state method and aliovalent cation. - Highlights: • Formation the high temperature cubic polymorph of zirconia using Ca-doping. • Solid state ceramic method was used for preparing the cubic Ca-doped zirconia. • Substitution of zirconium by calcium increases the lattice parameters and the bond length. • Ionic to electronic conductivity ratio enhanced considerably as Ca-doping level increases.

  5. Photoalignment control: self-focusing effect in hybrid- and homeotropic-aligned dye-doped polymer-stabilized liquid crystals

    NASA Astrophysics Data System (ADS)

    Wang, J.; Shishido, A.

    2015-09-01

    Nonlinear optics has drawn much attention for its great potential in applications, such as frequency conversion, multiple-photon absorption, self-focusing, and so on. However, such optical nonlinearities are generally observed at very high light intensities. In this study, we designed hybrid-aligned dye-doped polymer-stabilized liquid crystals (PSLC), in which the molecular director orientation gradually changes from homeotropic at one surface to homogeneous at the other. In such film, the threshold intensity required to form self-focusing effect was markedly reduced by a factor of 8.5 compared to that in a conventional homeotropic cell, which enabled the generation of the self-focusing effect using a handheld 1-mW laser pointer. In addition, we investigated the structural effect of dye molecules: azo-dye methyl red (MR, photoisomerizable)-doped PSLC was prepared and its NLO response was evaluated. It turned out that such MR-based LC system was not effective for self-focusing effect compared to oligothiophene-doped systems.

  6. Tailoring the magnetoelectric coupling in the Co2Y type hexaferrite single crystals by systematic doping control

    NASA Astrophysics Data System (ADS)

    Shin, Kwangwoo; Park, Chang Bae; Chun, Sae Hwan; Kim, Kee Hoon

    2015-03-01

    Hexagonal ferrites have shown gigantic magnetoelectric (ME) coupling in a broad temperature range including room temperature, which draws great interests due to their rich physics and various application potential. Here, we report the variations of the ME coupling and electrical phase boundary in the Sr and Al doped Co2Y type single crystal. As the doping ratio of Sr and Al ions increased, not only the transition temperature of the heliconical spin ordering increased up to 430 K, but also the ferroelectric phase boundary became closer to the zero magnetic field. These two main effects lead us to observe the large direct and converse ME effects at room temperature and near zero magnetic field. In particular, in an optimally doped sample, the ME susceptibility reaches to 28,000 ps/m at 10 K and the magnetization direction could be reversed by an external electric field even at 250 K without any bias magnetic field. These results clearly show that the Co2Y type hexaferrite is a promising material system that might realize the magnetization reversal even at room temperature.

  7. Supramolecular recognition control of polyethylene glycol modified N-doped graphene quantum dots: tunable selectivity for alkali and alkaline-earth metal ions.

    PubMed

    Yang, Siwei; Sun, Jing; Zhu, Chong; He, Peng; Peng, Zheng; Ding, Guqiao

    2016-02-01

    The graphene quantum dot based fluorescent probe community needs unambiguous evidence about the control on the ion selectivity. In this paper, polyethylene glycol modified N-doped graphene quantum dots (PN-GQDs) were synthesized by alkylation reaction between graphene quantum dots and organic halides. We demonstrate the tunable selectivity and sensitivity by controlling the supramolecular recognition through the length and the end group size of the polyether chain on PN-GQDs. The relationship formulae between the selectivity/detection limit and polyether chains are experimentally deduced. The polyether chain length determines the interaction between the PN-GQDs and ions with different ratios of charge to radius, which in turn leads to a good selectivity control. Meanwhile the detection limit shows an exponential growth with the size of end groups of the polyether chain. The PN-GQDs can be used as ultrasensitive and selective fluorescent probes for Li(+), Na(+), K(+), Mg(2+), Ca(2+) and Sr(2+), respectively. PMID:26730814

  8. A realistic bi-hemispheric model of the cerebellum uncovers the purpose of the abundant granule cells during motor control.

    PubMed

    Pinzon-Morales, Ruben-Dario; Hirata, Yutaka

    2015-01-01

    The cerebellar granule cells (GCs) have been proposed to perform lossless, adaptive spatio-temporal coding of incoming sensory/motor information required by downstream cerebellar circuits to support motor learning, motor coordination, and cognition. Here we use a physio-anatomically inspired bi-hemispheric cerebellar neuronal network (biCNN) to selectively enable/disable the output of GCs and evaluate the behavioral and neural consequences during three different control scenarios. The control scenarios are a simple direct current motor (1 degree of freedom: DOF), an unstable two-wheel balancing robot (2 DOFs), and a simulation model of a quadcopter (6 DOFs). Results showed that adequate control was maintained with a relatively small number of GCs (< 200) in all the control scenarios. However, the minimum number of GCs required to successfully govern each control plant increased with their complexity (i.e., DOFs). It was also shown that increasing the number of GCs resulted in higher robustness against changes in the initialization parameters of the biCNN model (i.e., synaptic connections and synaptic weights). Therefore, we suggest that the abundant GCs in the cerebellar cortex provide the computational power during the large repertoire of motor activities and motor plants the cerebellum is involved with, and bring robustness against changes in the cerebellar microcircuit (e.g., neuronal connections).

  9. A realistic bi-hemispheric model of the cerebellum uncovers the purpose of the abundant granule cells during motor control.

    PubMed

    Pinzon-Morales, Ruben-Dario; Hirata, Yutaka

    2015-01-01

    The cerebellar granule cells (GCs) have been proposed to perform lossless, adaptive spatio-temporal coding of incoming sensory/motor information required by downstream cerebellar circuits to support motor learning, motor coordination, and cognition. Here we use a physio-anatomically inspired bi-hemispheric cerebellar neuronal network (biCNN) to selectively enable/disable the output of GCs and evaluate the behavioral and neural consequences during three different control scenarios. The control scenarios are a simple direct current motor (1 degree of freedom: DOF), an unstable two-wheel balancing robot (2 DOFs), and a simulation model of a quadcopter (6 DOFs). Results showed that adequate control was maintained with a relatively small number of GCs (< 200) in all the control scenarios. However, the minimum number of GCs required to successfully govern each control plant increased with their complexity (i.e., DOFs). It was also shown that increasing the number of GCs resulted in higher robustness against changes in the initialization parameters of the biCNN model (i.e., synaptic connections and synaptic weights). Therefore, we suggest that the abundant GCs in the cerebellar cortex provide the computational power during the large repertoire of motor activities and motor plants the cerebellum is involved with, and bring robustness against changes in the cerebellar microcircuit (e.g., neuronal connections). PMID:25983678

  10. A realistic bi-hemispheric model of the cerebellum uncovers the purpose of the abundant granule cells during motor control

    PubMed Central

    Pinzon-Morales, Ruben-Dario; Hirata, Yutaka

    2015-01-01

    The cerebellar granule cells (GCs) have been proposed to perform lossless, adaptive spatio-temporal coding of incoming sensory/motor information required by downstream cerebellar circuits to support motor learning, motor coordination, and cognition. Here we use a physio-anatomically inspired bi-hemispheric cerebellar neuronal network (biCNN) to selectively enable/disable the output of GCs and evaluate the behavioral and neural consequences during three different control scenarios. The control scenarios are a simple direct current motor (1 degree of freedom: DOF), an unstable two-wheel balancing robot (2 DOFs), and a simulation model of a quadcopter (6 DOFs). Results showed that adequate control was maintained with a relatively small number of GCs (< 200) in all the control scenarios. However, the minimum number of GCs required to successfully govern each control plant increased with their complexity (i.e., DOFs). It was also shown that increasing the number of GCs resulted in higher robustness against changes in the initialization parameters of the biCNN model (i.e., synaptic connections and synaptic weights). Therefore, we suggest that the abundant GCs in the cerebellar cortex provide the computational power during the large repertoire of motor activities and motor plants the cerebellum is involved with, and bring robustness against changes in the cerebellar microcircuit (e.g., neuronal connections). PMID:25983678

  11. Solar Probe Plus: Motor Controllers Design for Manipulator for Calibration Purposes of SPAN-A and SPAN-B Instruments

    NASA Astrophysics Data System (ADS)

    Juache Aguilar, K.

    2015-12-01

    In preparation for the 2018 launch of Solar Probe Plus, and for the pre-flight tests of the SWEAP package, the instrument manipulator has been updated and modernized. Calibration of the Electrostatic Analyzers (ESA) is the critical last stop before launching instruments into space. The current method of controlling the instrument manipulator requires a dedicated computer, operating system, and power supplies. A novel solution integrates the power supplies, data acquisition, motor controller, and commanding microcontroller into one small enclosure. The system will also include software integration that communicates via Ethernet with electrical ground support equipment (EGSE) for full scripting automation during instrument calibration.

  12. Motor imagery, P300 and error-related EEG-based robot arm movement control for rehabilitation purpose.

    PubMed

    Bhattacharyya, Saugat; Konar, Amit; Tibarewala, D N

    2014-12-01

    The paper proposes a novel approach toward EEG-driven position control of a robot arm by utilizing motor imagery, P300 and error-related potentials (ErRP) to align the robot arm with desired target position. In the proposed scheme, the users generate motor imagery signals to control the motion of the robot arm. The P300 waveforms are detected when the user intends to stop the motion of the robot on reaching the goal position. The error potentials are employed as feedback response by the user. On detection of error the control system performs the necessary corrections on the robot arm. Here, an AdaBoost-Support Vector Machine (SVM) classifier is used to decode the 4-class motor imagery and an SVM is used to decode the presence of P300 and ErRP waveforms. The average steady-state error, peak overshoot and settling time obtained for our proposed approach is 0.045, 2.8% and 44 s, respectively, and the average rate of reaching the target is 95%. The results obtained for the proposed control scheme make it suitable for designs of prosthetics in rehabilitative applications.

  13. Synthesis and controllable oxidation of monodisperse cobalt-doped wüstite nanoparticles and their core-shell stability and exchange-bias stabilization

    NASA Astrophysics Data System (ADS)

    Chen, Chih-Jung; Chiang, Ray-Kuang; Kamali, Saeed; Wang, Sue-Lein

    2015-08-01

    Cobalt-doped wüstite (CWT), Co0.33Fe0.67O, nanoparticles were prepared via the thermal decomposition of CoFe2-oleate complexes in organic solvents. A controllable oxidation process was then performed to obtain Co0.33Fe0.67O/CoFe2O4 core-shell structures with different core-to-shell volume ratios and exchange bias properties. The oxidized core-shell samples with a ~4 nm CoFe2O4 shell showed good resistance to oxygen transmission. Thus, it is inferred that the cobalt ferrite shell provides a better oxidation barrier performance than magnetite in the un-doped case. The hysteresis loops of the oxidized 19 nm samples exhibited a high exchange bias field (HE), an enhanced coercivity field (HC), and a pronounced vertical shift, thus indicating the presence of a strong exchange bias coupling effect. More importantly, the onset temperature of HE was found to be higher than 200 K, which suggests that cobalt doping increases the Néel temperature (TN) of the CWT core. In general, the results show that the homogeneous dispersion of Co in iron precursors improves the stability of the final CWT nanoparticles. Moreover, the CoFe2O4 shells formed following oxidation increase the oxidation resistance of the CWT cores and enhance their anisotropy energy.Cobalt-doped wüstite (CWT), Co0.33Fe0.67O, nanoparticles were prepared via the thermal decomposition of CoFe2-oleate complexes in organic solvents. A controllable oxidation process was then performed to obtain Co0.33Fe0.67O/CoFe2O4 core-shell structures with different core-to-shell volume ratios and exchange bias properties. The oxidized core-shell samples with a ~4 nm CoFe2O4 shell showed good resistance to oxygen transmission. Thus, it is inferred that the cobalt ferrite shell provides a better oxidation barrier performance than magnetite in the un-doped case. The hysteresis loops of the oxidized 19 nm samples exhibited a high exchange bias field (HE), an enhanced coercivity field (HC), and a pronounced vertical shift, thus

  14. Distributed Blowing and Suction for the Purpose of Streak Control in a Boundary Layer Subjected to a Favorable Pressure Gradient

    NASA Technical Reports Server (NTRS)

    Forgoston, Eric; Tumin, Anatoli; Ashpis, David E.

    2005-01-01

    An analysis of the optimal control by blowing and suction in order to generate stream- wise velocity streaks is presented. The problem is examined using an iterative process that employs the Parabolized Stability Equations for an incompressible uid along with its adjoint equations. In particular, distributions of blowing and suction are computed for both the normal and tangential velocity perturbations for various choices of parameters.

  15. Mildronate (Meldonium) in professional sports – monitoring doping control urine samples using hydrophilic interaction liquid chromatography – high resolution/high accuracy mass spectrometry

    PubMed Central

    Görgens, Christian; Dib, Josef; Geyer, Hans; Schänzer, Wilhelm; Thevis, Mario

    2015-01-01

    To date, substances such as Mildronate (Meldonium) are not on the radar of anti‐doping laboratories as the compound is not explicitly classified as prohibited. However, the anti‐ischemic drug Mildronate demonstrates an increase in endurance performance of athletes, improved rehabilitation after exercise, protection against stress, and enhanced activations of central nervous system (CNS) functions. In the present study, the existing evidence of Mildronate's usage in sport, which is arguably not (exclusively) based on medicinal reasons, is corroborated by unequivocal analytical data allowing the estimation of the prevalence and extent of misuse in professional sports. Such data are vital to support decision‐making processes, particularly regarding the ban on drugs in sport. Due to the growing body of evidence (black market products and athlete statements) concerning its misuse in sport, adequate test methods for the reliable identification of Mildronate are required, especially since the substance has been added to the 2015 World Anti‐Doping Agency (WADA) monitoring program. In the present study, two approaches were established using an in‐house synthesized labelled internal standard (Mildronate‐D3). One aimed at the implementation of the analyte into routine doping control screening methods to enable its monitoring at the lowest possible additional workload for the laboratory, and another that is appropriate for the peculiar specifics of the analyte, allowing the unequivocal confirmation of findings using hydrophilic interaction liquid chromatography‐high resolution/high accuracy mass spectrometry (HILIC‐HRMS). Here, according to applicable regulations in sports drug testing, a full qualitative validation was conducted. The assay demonstrated good specificity, robustness (rRT=0.3%), precision (intra‐day: 7.0–8.4%; inter‐day: 9.9–12.9%), excellent linearity (R>0.99) and an adequate lower limit of detection (<10 ng/mL). © 2015 The Authors

  16. Mildronate (Meldonium) in professional sports - monitoring doping control urine samples using hydrophilic interaction liquid chromatography - high resolution/high accuracy mass spectrometry.

    PubMed

    Görgens, Christian; Guddat, Sven; Dib, Josef; Geyer, Hans; Schänzer, Wilhelm; Thevis, Mario

    2015-01-01

    To date, substances such as Mildronate (Meldonium) are not on the radar of anti-doping laboratories as the compound is not explicitly classified as prohibited. However, the anti-ischemic drug Mildronate demonstrates an increase in endurance performance of athletes, improved rehabilitation after exercise, protection against stress, and enhanced activations of central nervous system (CNS) functions. In the present study, the existing evidence of Mildronate's usage in sport, which is arguably not (exclusively) based on medicinal reasons, is corroborated by unequivocal analytical data allowing the estimation of the prevalence and extent of misuse in professional sports. Such data are vital to support decision-making processes, particularly regarding the ban on drugs in sport. Due to the growing body of evidence (black market products and athlete statements) concerning its misuse in sport, adequate test methods for the reliable identification of Mildronate are required, especially since the substance has been added to the 2015 World Anti-Doping Agency (WADA) monitoring program. In the present study, two approaches were established using an in-house synthesized labelled internal standard (Mildronate-D3 ). One aimed at the implementation of the analyte into routine doping control screening methods to enable its monitoring at the lowest possible additional workload for the laboratory, and another that is appropriate for the peculiar specifics of the analyte, allowing the unequivocal confirmation of findings using hydrophilic interaction liquid chromatography-high resolution/high accuracy mass spectrometry (HILIC-HRMS). Here, according to applicable regulations in sports drug testing, a full qualitative validation was conducted. The assay demonstrated good specificity, robustness (rRT=0.3%), precision (intra-day: 7.0-8.4%; inter-day: 9.9-12.9%), excellent linearity (R>0.99) and an adequate lower limit of detection (<10 ng/mL).

  17. Gene doping.

    PubMed

    Harridge, Stephen D R; Velloso, Cristiana P

    2008-01-01

    Gene doping is the misuse of gene therapy to enhance athletic performance. It has recently been recognised as a potential threat and subsequently been prohibited by the World Anti-Doping Agency. Despite concerns with safety and efficacy of gene therapy, the technology is progressing steadily. Many of the genes/proteins which are involved in determining key components of athletic performance have been identified. Naturally occurring mutations in humans as well as gene-transfer experiments in adult animals have shown that altered expression of these genes does indeed affect physical performance. For athletes, however, the gains in performance must be weighed against the health risks associated with the gene-transfer process, whereas the detection of such practices will provide new challenges for the anti-doping authorities.

  18. Rare earth doped LiYbF{sub 4} phosphors with controlled morphologies: Hydrothermal synthesis and luminescent properties

    SciTech Connect

    Huang, Wenjuan; Lu, Chunhua; Jiang, Chenfei; Jin, Junyang; Ding, Mingye; Ni, Yaru; Xu, Zhongzi

    2012-06-15

    Highlights: ► LiYbF{sub 4} microparticles as an excellent upconverting materials. ► High temperature and long time can favor high crystalline LiYbF{sub 4} microparticles. ► The shape of LiYbF{sub 4} microparticles can be tuned by the molar ratio of EDTA to Yb{sup 3+}. ► Bright green emission can be obtained by changing the doping concentration of Er{sup 3+}. -- Abstract: High quality monodisperse LiYbF{sub 4} microparticles with shape of octahedron had been prepared via a facile hydrothermal route. The crystalline phase, size, morphology and luminescence properties were characterized by X-ray diffraction (XRD), scanning electron microscopy (SEM), photoluminescence (PL) spectra and Commission Internationale de L’Eclairage (CIE 1931) chromaticity coordinates, respectively. The influences of reaction temperature, reaction time and the molar ratio of EDTA to Yb{sup 3+} on the crystal phases and shapes of as-prepared products had been investigated in detail. The upconversion (UC) luminescence properties of LiYb{sub 1−x}F{sub 4}:xEr{sup 3+} (x =0.1, 0.2, 0.5, 1, 2, 5 and 10 mol%) particles with octahedral microstructures were studied under 976 nm excitation. The results showed that the luminescence colors of the corresponding products could be tuned to bright green by changing the doping concentration of Er{sup 3+} ion. The luminescence mechanisms for the doped Er{sup 3+} ion were thoroughly analyzed, showing great potential in applications such as biolabels, displays and other optical technologies.

  19. Dynamic polarization grating based on a dye-doped liquid crystal controllable by a single beam in a homeotropic-planar geometry.

    PubMed

    Kim, Hak-Rin; Jang, Eunje; Kim, Jiyoon; Joo, Kyung-Il; Lee, Sin-Doo

    2012-12-20

    We present a dynamic polarization grating based on a dye-doped liquid crystal cell that is controllable by a single pump beam in a binary homeotropic-planar configuration produced through selective rubbing. Upon single pump beam irradiation, the azo dyes in the liquid-crystal (LC) layer diffuse and adsorb onto the planar LC-anchoring surface due to trans-cis photo-isomerization. It is found that the dynamic polarization grating effect results mainly from the photo-induced easy axis reorientation by the amount of dye molecules adsorbed on the planar LC-alignment surface in a single-beam control scheme. The initial LC-anchoring conditions and the dynamic behavior of the dye adsorption strongly influence the repetitive writing-erasing processes by the single pump beam. PMID:23262590

  20. Temperature-controlled spin filter and spin valve based on Fe-doped monolayer MoS2.

    PubMed

    Zou, Fei; Zhu, Lin; Gao, Gaoying; Wu, Menghao; Yao, Kailun

    2016-02-17

    The thermal transport properties of an iron-doped molybdenum disulfide system were explored theoretically using the density functional theory calculations combined with the Keldysh non-equilibrium Green's function approach. The results indicate that a perfect spin filtering effect and spin Seebeck effect are induced thermally. Excellently, there exists thermal colossal magnetoresistances, which exhibit a transition between positive and negative that can be tuned using temperature. These features were elucidated using the band structures of the electrodes and the transmission function together with current spectra. Our findings may be helpful in the design of highly efficient spin caloritronic devices.

  1. Examples of doping control analysis by liquid chromatography-tandem mass spectrometry: ephedrines, beta-receptor blocking agents, diuretics, sympathomimetics, and cross-linked hemoglobins.

    PubMed

    Thevis, Mario; Schänzer, Wilhelm

    2005-01-01

    The application of modern and powerful analytical instruments consisting of liquid chromatographs (LCs), sophisticated atmospheric pressure ion sources, and sensitive mass analyzers has improved quality as well as speed of doping control analyses markedly during the last 5 years. Numerous compounds such as beta-receptor blocking agents or diuretics require derivatization prior to gas chromatographic (GC) and mass spectrometric (MS) measurement, which is the reason for extended sample preparation periods. In addition, several substances demonstrate poor GC-MS properties even after chemical modification, and peptide hormones such as cross-linked hemoglobins cannot be analyzed at all by means of GC-MS. With the availability of electrospray ionization and robust tandem MSs (e.g., triple-stage quadrupole or ion trap instruments) many new or complementary screening and confirmation assays have been developed, providing detailed qualitative and quantitative information on prohibited drugs. With selected categories of compounds (ephedrines, beta-blockers, b2-agonists, diuretics, and bovine hemoglobin-based oxygen therapeutics) that are banned according to the rules of the World Anti-Doping Agency and International Olympic Committee, the advantages of LC-MS-MS procedures over conventional GC-MS assays are demonstrated, such as enhanced separation of analytes, shorter sample pretreatment, and identification of substances that are not identified by GC-MS. PMID:15808003

  2. Ti-Doped Indium Tin Oxide Thin Films for Transparent Field-Effect Transistors: Control of Charge-Carrier Density and Crystalline Structure

    SciTech Connect

    J Kim; K Ji; M Jang; H Yang; R Choi; J Jeong

    2011-12-31

    Indium tin oxide (ITO) films are representative transparent conducting oxide media for organic light-emitting diodes, liquid crystal displays, and solar cell applications. Extending the utility of ITO films from passive electrodes to active channel layers in transparent field-effect transistors (FETs), however, has been largely limited because of the materials' high carrier density (>1 x 10{sup 20} cm{sup 03}), wide band gap, and polycrystalline structure. Here, we demonstrate that control over the cation composition in ITO-based oxide films via solid doping of titanium (Ti) can optimize the carrier concentration and suppress film crystallization. On 120 nm thick SiO{sub 2}/Mo (200 nm)/glass substrates, transparent n-type FETs prepared with 4 at % Ti-doped ITO films and fabricated via the cosputtering of ITO and TiO{sub 2} exhibited high electron mobilities of 13.4 cm{sup 2} V{sup -1} s{sup -1}, a low subthreshold gate swing of 0.25 V decade{sup -1}, and a high I{sub on}/I{sub off} ratio of >1 x 10{sup 8}.

  3. Enzyme-linked immunosorbent assays for doping control of 5alpha-reductase inhibitors finasteride and dutasteride.

    PubMed

    Brun, Eva M; Torres, Ana; Ventura, Rosa; Puchades, Rosa; Maquieira, Angel

    2010-06-25

    Finasteride and dutasteride are 5alpha-reductase inhibitors included in the World Anti-Doping Agency's list of banned substances. Two highly sensitive and selective ELISA assays were developed for these compounds. Polyclonal rabbit antibodies were raised using synthesized haptens and other commercial products. The best immunoassay obtained, based on an antibody-coated format, showed a limit of detection of 0.01 microg L(-1) and an IC(50) of 0.75 microg L(-1) for finasteride (cross-reactivity with dutasteride<4%). The second assay allowed finasteride and dutasteride determination, with limits of detection of 0.013 and 0.021 microg L(-1), and IC(50) values 0.18 and 1.18 microg L(-1), respectively. Both assays were highly selective to a set of anabolic steroids, but they showed 37% and 30% cross-reactivity with the major urinary metabolite of finasteride, allowing its determination. The developed ELISA had better sensitivity than HPLC/MS/MS method and was applied as a screening technique to quantify dutasteride, finasteride, and its main metabolite in human urine without sample pre-treatment. Moreover, the analysis of dutasteride's excretion urines by ELISA was used to obtain its human excretion rate, essential to improve the analytical strategies about this type of drugs (permitted as medicines and prohibited in sport) and to establish an effective anti-doping policy. PMID:20541645

  4. Doped colorimetric assay liposomes

    DOEpatents

    Charych, Deborah; Stevens, Raymond C.

    2001-01-01

    The present invention provides compositions comprising colorimetric assay liposomes. The present invention also provides methods for producing colorimetric liposomes and calorimetric liposome assay systems. In preferred embodiments, these calorimetric liposome systems provide high levels of sensitivity through the use of dopant molecules. As these dopants allow the controlled destabilization of the liposome structure, upon exposure of the doped liposomes to analyte(s) of interest, the indicator color change is facilitated and more easily recognized.

  5. Possible size control and emission characteristics of Eu3+-doped Y2O3 nanoparticles synthesized by surfactant-assembly

    NASA Astrophysics Data System (ADS)

    Akita, Yukihiko; Harada, Takashi; Sasai, Ryo; Tomita, Koji; Nishiyama, Katsura

    2016-08-01

    Yttrium oxide nanoparticles doped with 2.0 wt% Eu (Eu@Y2O3) were synthesized via the surfactant-assembly method. The average diameter of Eu@Y2O3 (dav) depends on the alkyl chain number (N) of the sodium alkyl sulfates employed as surfactants. Using surfactants with N = 8, 10, and 12, Eu@Y2O3 with dav = 35, 200, and 500 nm, respectively were obtained. Such changes in dav are ascribed to the difference in the micelle aggregation numbers, supporting the use of rare-earth ions in the assembly. The Eu@Y2O3 particles synthesized presently emitted through Eu3+ transitions under UV excitation of Y2O3, making them applicable to nanoemitters.

  6. Polarity control and transport properties of Mg-doped (0001) InN by plasma-assisted molecular beam epitaxy

    SciTech Connect

    Choi, Soojeong; Wu Feng; Bierwagen, Oliver; Speck, James S.

    2013-05-15

    The authors report on the plasma-assisted molecular beam epitaxy growth and carrier transport of Mg-doped In-face (0001) InN. The 1.2 {mu}m thick InN films were grown on GaN:Fe templates under metal rich conditions with Mg concentration from 1 Multiplication-Sign 10{sup 17}/cm{sup 3} to 3 Multiplication-Sign 10{sup 20}/cm{sup 3}. A morphological transition, associated with the formation of V-shape polarity inversion domains, was observed at Mg concentration over 7 Multiplication-Sign 10{sup 19}/cm{sup 3} by atomic force microscopy and transmission electron microscopy. Seebeck measurements indicated p-type conductivity for Mg-concentrations from 9 Multiplication-Sign 10{sup 17}/cm{sup 3} to 7 Multiplication-Sign 10{sup 19}/cm{sup 3}, i.e., as it exceeded the compensating (unintentional) donor concentration.

  7. Optimization and control of the sweeping range in an Yb-doped self-sweeping fiber laser

    NASA Astrophysics Data System (ADS)

    Lobach, I. A.; Tkachenko, A. Yu; Kablukov, S. I.

    2016-04-01

    Influence of the laser cavity parameters (an active fiber length and output coupling losses) and the temperature of elements (active fiber and pump laser diode) on the sweeping range in an Yb-doped self-sweeping laser is investigated. The obtained results show that the sweeping spectral region is shifted to shorter wavelengths for shorter active fibers and with increasing absorbed power. This allows one to obtain self-sweeping operation in a broad range within a ytterbium gain bandwidth from 1028 to 1080 nm. At the same time, there are optimal cavity parameters at which the sweeping span is the broadest (>20 nm). Good agreement between the experimental sweeping range and the calculated maximum gain wavelength is demonstrated.

  8. Repetition rate stabilization of an erbium-doped all-fiber laser via opto-mechanical control of the intracavity group velocity

    SciTech Connect

    Shen, Xuling; He, Boqu; Zhao, Jian; Liu, Yang; Bai, Dongbi; Wang, Chao; Liu, Geping; Luo, Daping; Liu, Fengjiang; Li, Wenxue; Zeng, Heping; Yang, Kangwen; Hao, Qiang

    2015-01-19

    We present a method for stabilizing the repetition rate of an erbium-doped all-fiber laser by inserting an electronic polarization controller (EPC) in the fiber laser cavity. The device exhibited good integration, low cost, and convenient operation. Such a repetition rate stabilization may facilitate an all-fiber laser comb system with high integration. The repetition rate was phase-locked to a Rb reference more than 72 h with a low feedback voltage applied to one channel of the EPC. The repetition rate was 74.6 MHz. The standard deviation and the repetition rate linewidth were 1.4 and 1.7 mHz, respectively.

  9. Homogeneous double-layer amorphous Si-doped indium oxide thin-film transistors for control of turn-on voltage

    NASA Astrophysics Data System (ADS)

    Kizu, Takio; Aikawa, Shinya; Nabatame, Toshihide; Fujiwara, Akihiko; Ito, Kazuhiro; Takahashi, Makoto; Tsukagoshi, Kazuhito

    2016-07-01

    We fabricated homogeneous double-layer amorphous Si-doped indium oxide (ISO) thin-film transistors (TFTs) with an insulating ISO cap layer on top of a semiconducting ISO bottom channel layer. The homogeneously stacked ISO TFT exhibited high mobility (19.6 cm2/V s) and normally-off characteristics after annealing in air. It exhibited normally-off characteristics because the ISO insulator suppressed oxygen desorption, which suppressed the formation of oxygen vacancies (VO) in the semiconducting ISO. Furthermore, we investigated the recovery of the double-layer ISO TFT, after a large negative shift in turn-on voltage caused by hydrogen annealing, by treating it with annealing in ozone. The recovery in turn-on voltage indicates that the dense VO in the semiconducting ISO can be partially filled through the insulator ISO. Controlling molecule penetration in the homogeneous double layer is useful for adjusting the properties of TFTs in advanced oxide electronics.

  10. High-speed gas chromatography in doping control: fast-GC and fast-GC/MS determination of beta-adrenoceptor ligands and diuretics.

    PubMed

    Brunelli, Claudio; Bicchi, Carlo; Di Stilo, Antonella; Salomone, Alberto; Vincenti, Marco

    2006-12-01

    In official doping controls, about 300 drugs and metabolites have to be screened for each sample. Moreover, the number of determinations to be routinely processed increases continuously as the number of both samples and potential illicit drugs keeps growing. As a consequence, increasingly specific, sensitive, and, above all, fast methods for doping controls are needed. The present study presents an efficient fast-GC/MS approach to the routine screening of two different classes of doping agents, namely beta-adrenoceptor ligands and diuretics (belonging to the S3, P2, and S5 groups of the WADA list of prohibited substances). Narrow bore columns (100 mm id) of different lengths and coated with apolar stationary phases were successfully used to separate the derivatized analytes; preliminary experiments (results not shown) showed better performances with OV-1701 for the separation of beta-adrenoceptor ligands. On the same stationary phase some diuretics required too high a temperature or a long isothermal time for elution, in which case a DB1-MS column was preferred. Two methods of sample preparation, derivatization, and analysis were used on aqueous standard mixtures of, respectively, (i) eight beta-adrenoceptor ligands, including five beta-antagonists (acebutolol, alprenolol, atenolol, metoprolol, pindolol) and three beta2-agonists (salbutamol, clenbuterol, terbutaline) and (ii) seventeen diuretic drugs (acetazolamide, althiazide, bendroflumethiazide, bumethanide, canrenone, chlorothiazide, chlortalidone, clopamide, ethacrinic acid, furosemide, hydrochlorothiazide, hydroflumethiazide, indapamide, indomethacine, spironolactone, triamterene, trichloromethiazide) and one masking agent (probenecid). The mixture of beta-adrenoceptor ligand derivatives was efficiently separated in about 5.6 min, while the one of 18 diuretics and masking agents required less than 5 min for analysis. Limits of detection were from 1 microg/L for pindolol, ethacrinic acid, furosemide

  11. Doping in sport: a review of elite athletes' attitudes, beliefs, and knowledge.

    PubMed

    Morente-Sánchez, Jaime; Zabala, Mikel

    2013-06-01

    Doping in sport is a well-known phenomenon that has been studied mainly from a biomedical point of view, even though psychosocial approaches are also key factors in the fight against doping. This phenomenon has evolved greatly in recent years, and greater understanding of it is essential for developing efficient prevention programmes. In the psychosocial approach, attitudes are considered an index of doping behaviour, relating the use of banned substances to greater leniency towards doping. The aim of this review is to gather and critically analyse the most recent publications describing elite athletes' attitudes, beliefs and knowledge of doping in sport, to better understand the foundations provided by the previous work, and to help develop practical strategies to efficiently combat doping. For this purpose, we performed a literature search using combinations of the terms "doping", "sport", "elite athletes", "attitudes", "beliefs", "knowledge", "drugs", and "performance-enhancing substances" (PES). A total of 33 studies were subjected to comprehensive assessment using articles published between 2000 and 2011. All of the reports focused on elite athletes and described their attitudes, beliefs and knowledge of doping in sport. The initial reasons given for using banned substances included achievement of athletic success by improving performance, financial gain, improving recovery and prevention of nutritional deficiencies, as well as the idea that others use them, or the "false consensus effect". Although most athletes acknowledge that doping is cheating, unhealthy and risky because of sanctions, its effectiveness is also widely recognized. There is a general belief about the inefficacy of anti-doping programmes, and athletes criticise the way tests are carried out. Most athletes consider the severity of punishment is appropriate or not severe enough. There are some differences between sports, as team-based sports and sports requiring motor skills could be less

  12. Controllable GMR device in a δ-doped, magnetically and electrically modulated, GaAs /Alx Ga1-x As heterostructure

    NASA Astrophysics Data System (ADS)

    Shen, Li-Hua; Zhang, Gui-Lian; Yang, Duan-Chui

    2016-09-01

    We report on a theoretical study of giant magnetoresistance (GMR) effect in a δ-doped GaAs /Alx Ga1-x As heterostructure modulated by two stripes of ferromagnetic metal and a stripe of Schottky metal in parallel configuration. The δ-doping dependent transmission and conductance of the device are calculated. It is shown that a considerable giant magnetoresistance (GMR) effect exists in this structure. It is also shown that the magnetoresistance ratio (MR) can be switched by the δ-doping. The underlying physical mechanism of the results is analysed in light of δ-doping-dependent tunneling process in the device.

  13. Quasiparticle excitations of adsorbates on doped graphene

    NASA Astrophysics Data System (ADS)

    Lischner, Johannes; Wickenburg, Sebastian; Wong, Dillon; Karrasch, Christoph; Wang, Yang; Lu, Jiong; Omrani, Arash A.; Brar, Victor; Tsai, Hsin-Zon; Wu, Qiong; Corsetti, Fabiano; Mostofi, Arash; Kawakami, Roland K.; Moore, Joel; Zettl, Alex; Louie, Steven G.; Crommie, Mike

    Adsorbed atoms and molecules can modify the electronic structure of graphene, but in turn it is also possible to control the properties of adsorbates via the graphene substrate. In my talk, I will discuss the electronic structure of F4-TCNQ molecules on doped graphene and present a first-principles based theory of quasiparticle excitations that captures the interplay of doping-dependent image charge interactions between substrate and adsorbate and electron-electron interaction effects on the molecule. The resulting doping-dependent quasiparticle energies will be compared to experimental scanning tunnelling spectra. Finally, I will also discuss the effects of charged adsorbates on the electronic structure of doped graphene.

  14. Development of criteria for the detection of adrenosterone administration by gas chromatography-mass spectrometry and gas chromatography-combustion-isotope ratio mass spectrometry for doping control.

    PubMed

    Brooker, Lance; Parr, Maria Kristina; Cawley, Adam; Flenker, Ulrich; Howe, Christopher; Kazlauskas, Rymantas; Schänzer, Wilhelm; George, Adrian

    2009-11-01

    Adrenosterone (androst-4-ene-3,11,17-trione, 11-oxoandrostenedione) is an endogenous steroid hormone that has been promoted as a dietary supplement capable of reducing body fat and increasing muscle mass. It is proposed that adrenosterone may function as an inhibitor of the 11beta-hydroxysteroid dehydrogenase type 1 enzyme (11beta-HSD1), which is primarily responsible for reactivation of cortisol from cortisone. The urinary metabolism of adrenosterone was investigated, after a single oral administration in two male subjects, by gas chromatography-mass spectrometry (GC-MS) and gas chromatography-combustion-isotope ratio mass spectrometry (GC-C-IRMS). Substantially increased excretion of 11beta-hydroxyandrosterone, 11beta-hydroxyetiocholanolone, 11-oxoandrosterone and 11-oxoetiocholanolone was observed. Minor metabolites such as 3alpha,17beta-dihydroxy-5beta-androstan-11-one, 3alpha-hydroxyandrost-4-ene-11,17-dione and 3alpha,11beta-dihydroxyandrost-4-en-17-one were also identified. The exogenous origin of the most abundant adrenosterone metabolites was confirmed by GC-C-IRMS according to World Anti-Doping Agency criteria. Through analysis of a reference population data set obtained from urine samples provided by elite athlete volunteers (n = 85), GC-MS doping control screening criteria are proposed: 11beta-hydroxyandrosterone concentration greater than 10 000 ng/mL (specific gravity adjusted to 1.020) or 11beta-hydroxyandrosterone/11beta-hydroxyetiocholanolone ratio greater than 20.Urine samples fulfilling these screening criteria may be subjected to GC-C-IRMS analysis for confirmation of adrenosterone administration.

  15. Controlling sensitivity and stability of ferrous-xylenol orange-gelatin 3D gel dosimeters by doping with phenanthroline-type ligands and glyoxal

    NASA Astrophysics Data System (ADS)

    Penev, Kalin I.; Mequanint, Kibret

    2013-03-01

    The ferrous-xylenol orange-gelatin (FXG) dosimeter is widely used for three-dimensional ionizing radiation field mapping through optical scanning. Upon irradiation, the ferrous iron (Fe2+) is oxidized to ferric iron (Fe3+), which forms an intensely coloured complex with xylenol orange (XO). XO also acts as a diffusion-limiting additive; however, its presence may cause rapid auto-oxidation of Fe2+ during storage and low stability of the dose response. In this work, phenanthroline-type ligands were added to FXG system in a bid to bind the ferrous iron in a stable complex and minimize the rate of the auto-oxidation, whereas glyoxal was used as a chemical cross-linker, aiming to minimize the ferric iron diffusion. It was found that addition of either 1,10-phenanthroline or 5-nitro-1,10-phenanthroline can improve the auto-oxidation behaviour of the gels. However, the initial background absorbance was slightly increased, and the sensitivity of the dosimeters was decreased. Doping with glyoxal led to a moderate decrease of the diffusion only in those gels that also contained a phenanthroline-type ligand, and did not affect the initial dose response. Glyoxal also afforded an extended period of stable background absorbance level after an initial period of bleaching of the gel. Following re-irradiation, most glyoxal-containing dosimeters showed an excellent linearity of the dose response, albeit at a decreased sensitivity. We recommend further testing of FXG dosimeters, doped with phenanthroline-type ligands and glyoxal as a means for controlling the dose response and improving the long-term storage properties of the gels and the potential for dose fractionation.

  16. Visible-Light-Induced Activity Control of Peroxidase Bound to Fe-Doped Titanate Nanosheets with Nanometric Lateral Dimensions.

    PubMed

    Kamada, Kai; Ito, Daiki; Soh, Nobuaki

    2015-10-21

    Catalytic performance of horseradish peroxidase (HRP) electrostatically adsorbed on nanometric and semiconducting Fe-doped titanate (FT) nanosheets was successfully manipulated by visible light illumination. A colloidal solution of FT with a narrow band gap corresponding to a visible light region was fabricated through a hydrolysis reaction of metals sources. HRP could be easily bound to the FT at pH = 4 through an electrostatic interaction between them, and the formed HRP-FT was utilized for the visible-light-driven enzymatic reaction. Under exposure to visible light with enough energy for band gap excitation of the FT, catalytic activity of HRP-FT was dramatically enhanced as compared with free (unbound) HRP and was simply adjusted by light intensity. In addition, wavelength dependence of an enzymatic reaction rate was analogous to an optical absorption spectrum of the FT. These results substantiated an expected reaction mechanism in which the photoenzymatic reaction was initiated by band gap excitation of FT followed by transferring holes generated in the valence band of irradiated FT to HRP. The excited HRP oxidized substrates (amplex ultrared: AUR) accompanied by two-electron reduction to regenerate the resting state. In addition, the catalytic activity was clearly switched by turning on and off the light source.

  17. Reactive pulsed-DC sputtered Nb-doped VO2 coatings for smart thermochromic windows with active solar control.

    PubMed

    Batista, C; Carneiro, J; Ribeiro, R M; Teixeira, V

    2011-10-01

    Thermochromic VO2 thin films have successfully been grown on SiO2-coated float glass by reactive pulsed-DC magnetron sputtering. Different Nb doping amounts were introduced in the VO2 solid solution during the film growing which resulted in films with distinct semiconducting-metal phase transition temperatures. Pure VO2 showed improved thermochromic behavior as compared with VO2 films prepared by conventional DC sputtering. The transition temperatures were linearly decreased from 59 down to 34 degrees C with the increase in Nb content. However, the luminous transmittance and the infrared modulation efficiency were markedly affected. The surface morphology of the films was examined by scanning electron microscopy (SEM) and showed a tendency for grain sized reduction due to Nb addition. Moreover, the films were found to be very dense with no columnar microstructure. Structural analyses carried out by X-ray diffractometry (XRD) revealed that Nb introduces significant amount of defects in the crystal lattice which clearly degrade the optical properties.

  18. Optical control of the spindle-liked ZnSe quantum dots with precursor solvent and Mn doping

    NASA Astrophysics Data System (ADS)

    Chen, Qiu-Hang; Zhang, Jie; Chen, Guo-Ping; Guo, Rui-Qian

    2013-11-01

    Spindle-liked ZnSe and Mn:ZnSe quantum dots (QDs) were formed via an optimized greener approach, which may be attributed to the amine ligands adhering asymmetrically to the crystal facets. Powder X-ray diffraction (XRD) patterns revealed that the ZnSe and Mn:ZnSe QDs have a zinc blende cubic crystal structure. The crystallite size of ZnSe was calculated to be about 4 nm from the (1 1 1) peak width using the Scherrer equation, which was in agreement with the HRTEM findings. The fluorescence emission peak of as-prepared ZnSe and Mn:ZnSe QDs was 431 nm and 580 nm respectively. We investigated the effect of the reaction temperature, reflux time, precursor solvent, size of MnSe core and overcoating temperature of ZnSe layer on the optical properties of ZnSe and Mn:ZnSe QDs. It is shown that the precursor solvent plays a key role in the formation of the magic-sized QDs (MSQDs). And as a result, doped quantum dots (d-dots) showed a large Stokes shift and enhanced photoluminescence, and smaller size of the MnSe core and suitable overcoating temperature of ZnSe shell were identified as two key parameters for obtaining the high quality d-dots.

  19. Chemical approaches for doping nanodevice architectures.

    PubMed

    O'Connell, John; Biswas, Subhajit; Duffy, Ray; Holmes, Justin D

    2016-08-26

    Advanced doping technologies are key for the continued scaling of semiconductor devices and the maintenance of device performance beyond the 14 nm technology node. Due to limitations of conventional ion-beam implantation with thin body and 3D device geometries, techniques which allow precise control over dopant diffusion and concentration, in addition to excellent conformality on 3D device surfaces, are required. Spin-on doping has shown promise as a conventional technique for doping new materials, particularly through application with other dopant methods, but may not be suitable for conformal doping of nanostructures. Additionally, residues remain after most spin-on-doping processes which are often difficult to remove. In situ doping of nanostructures is especially common for bottom-up grown nanostructures but problems associated with concentration gradients and morphology changes are commonly experienced. Monolayer doping has been shown to satisfy the requirements for extended defect-free, conformal and controllable doping on many materials ranging from traditional silicon and germanium devices to emerging replacement materials such as III-V compounds but challenges still remain, especially with regard to metrology and surface chemistry at such small feature sizes. This article summarises and critically assesses developments over the last number of years regarding the application of gas and solution phase techniques to dope silicon-, germanium- and III-V-based materials and nanostructures to obtain shallow diffusion depths coupled with high carrier concentrations and abrupt junctions. PMID:27418239

  20. Chemical approaches for doping nanodevice architectures

    NASA Astrophysics Data System (ADS)

    O’Connell, John; Biswas, Subhajit; Duffy, Ray; Holmes, Justin D.

    2016-08-01

    Advanced doping technologies are key for the continued scaling of semiconductor devices and the maintenance of device performance beyond the 14 nm technology node. Due to limitations of conventional ion-beam implantation with thin body and 3D device geometries, techniques which allow precise control over dopant diffusion and concentration, in addition to excellent conformality on 3D device surfaces, are required. Spin-on doping has shown promise as a conventional technique for doping new materials, particularly through application with other dopant methods, but may not be suitable for conformal doping of nanostructures. Additionally, residues remain after most spin-on-doping processes which are often difficult to remove. In situ doping of nanostructures is especially common for bottom-up grown nanostructures but problems associated with concentration gradients and morphology changes are commonly experienced. Monolayer doping has been shown to satisfy the requirements for extended defect-free, conformal and controllable doping on many materials ranging from traditional silicon and germanium devices to emerging replacement materials such as III–V compounds but challenges still remain, especially with regard to metrology and surface chemistry at such small feature sizes. This article summarises and critically assesses developments over the last number of years regarding the application of gas and solution phase techniques to dope silicon-, germanium- and III–V-based materials and nanostructures to obtain shallow diffusion depths coupled with high carrier concentrations and abrupt junctions.

  1. Chemical approaches for doping nanodevice architectures

    NASA Astrophysics Data System (ADS)

    O'Connell, John; Biswas, Subhajit; Duffy, Ray; Holmes, Justin D.

    2016-08-01

    Advanced doping technologies are key for the continued scaling of semiconductor devices and the maintenance of device performance beyond the 14 nm technology node. Due to limitations of conventional ion-beam implantation with thin body and 3D device geometries, techniques which allow precise control over dopant diffusion and concentration, in addition to excellent conformality on 3D device surfaces, are required. Spin-on doping has shown promise as a conventional technique for doping new materials, particularly through application with other dopant methods, but may not be suitable for conformal doping of nanostructures. Additionally, residues remain after most spin-on-doping processes which are often difficult to remove. In situ doping of nanostructures is especially common for bottom-up grown nanostructures but problems associated with concentration gradients and morphology changes are commonly experienced. Monolayer doping has been shown to satisfy the requirements for extended defect-free, conformal and controllable doping on many materials ranging from traditional silicon and germanium devices to emerging replacement materials such as III-V compounds but challenges still remain, especially with regard to metrology and surface chemistry at such small feature sizes. This article summarises and critically assesses developments over the last number of years regarding the application of gas and solution phase techniques to dope silicon-, germanium- and III-V-based materials and nanostructures to obtain shallow diffusion depths coupled with high carrier concentrations and abrupt junctions.

  2. Electro-thermal control of aluminum-doped zinc oxide/vanadium dioxide multilayered thin films for smart-device applications

    NASA Astrophysics Data System (ADS)

    Skuza, J. R.; Scott, D. W.; Mundle, R. M.; Pradhan, A. K.

    2016-02-01

    We demonstrate the electro-thermal control of aluminum-doped zinc oxide (Al:ZnO) /vanadium dioxide (VO2) multilayered thin films, where the application of a small electric field enables precise control of the applied heat to the VO2 thin film to induce its semiconductor-metal transition (SMT). The transparent conducting oxide nature of the top Al:ZnO film can be tuned to facilitate the fine control of the SMT of the VO2 thin film and its associated properties. In addition, the Al:ZnO film provides a capping layer to the VO2 thin film, which inhibits oxidation to a more energetically favorable and stable V2O5 phase. It also decreases the SMT of the VO2 thin film by approximately 5-10 °C because of an additional stress induced on the VO2 thin film and/or an alteration of the oxygen vacancy concentration in the VO2 thin film. These results have significant impacts on technological applications for both passive and active devices by exploiting this near-room-temperature SMT.

  3. Electro-thermal control of aluminum-doped zinc oxide/vanadium dioxide multilayered thin films for smart-device applications.

    PubMed

    Skuza, J R; Scott, D W; Mundle, R M; Pradhan, A K

    2016-02-17

    We demonstrate the electro-thermal control of aluminum-doped zinc oxide (Al:ZnO) /vanadium dioxide (VO2) multilayered thin films, where the application of a small electric field enables precise control of the applied heat to the VO2 thin film to induce its semiconductor-metal transition (SMT). The transparent conducting oxide nature of the top Al:ZnO film can be tuned to facilitate the fine control of the SMT of the VO2 thin film and its associated properties. In addition, the Al:ZnO film provides a capping layer to the VO2 thin film, which inhibits oxidation to a more energetically favorable and stable V2O5 phase. It also decreases the SMT of the VO2 thin film by approximately 5-10 °C because of an additional stress induced on the VO2 thin film and/or an alteration of the oxygen vacancy concentration in the VO2 thin film. These results have significant impacts on technological applications for both passive and active devices by exploiting this near-room-temperature SMT.

  4. Morphological appearances and photo-controllable coloration of dye-doped cholesteric liquid crystal/polymer coaxial microfibers fabricated by coaxial electrospinning technique.

    PubMed

    Lin, Jia-De; Chen, Che-Pei; Chen, Lin-Jer; Chuang, Yu-Chou; Huang, Shuan-Yu; Lee, Chia-Rong

    2016-02-01

    This study systematically investigates the morphological appearance of azo-chiral dye-doped cholesteric liquid crystal (DDCLC)/polymer coaxial microfibers obtained through the coaxial electrospinning technique and examines, for the first time, their photocontrollable reflection characteristics. Experimental results show that the quasi-continuous electrospun microfibers can be successfully fabricated at a high polymer concentration of 17.5 wt% and an optimum ratio of 2 for the feeding rates of sheath to core materials at 25 °C and a high humidity of 50% ± 2% in the spinning chamber. Furthermore, the optical controllability of the reflective features for the electrospun fibers is studied in detail by changing the concentration of the azo-chiral dopant in the core material, the UV irradiation intensity, and the core diameter of the fibers. Relevant mechanisms are addressed to explain the optical-control behaviors of the DDCLC coaxial fibers. Considering the results, optically controllable DDCLC coaxial microfibers present potential applications in UV microsensors and wearable smart textiles or swabs. PMID:26906876

  5. Electro-thermal control of aluminum-doped zinc oxide/vanadium dioxide multilayered thin films for smart-device applications

    PubMed Central

    Skuza, J. R.; Scott, D. W.; Mundle, R. M.; Pradhan, A. K.

    2016-01-01

    We demonstrate the electro-thermal control of aluminum-doped zinc oxide (Al:ZnO) /vanadium dioxide (VO2) multilayered thin films, where the application of a small electric field enables precise control of the applied heat to the VO2 thin film to induce its semiconductor-metal transition (SMT). The transparent conducting oxide nature of the top Al:ZnO film can be tuned to facilitate the fine control of the SMT of the VO2 thin film and its associated properties. In addition, the Al:ZnO film provides a capping layer to the VO2 thin film, which inhibits oxidation to a more energetically favorable and stable V2O5 phase. It also decreases the SMT of the VO2 thin film by approximately 5–10 °C because of an additional stress induced on the VO2 thin film and/or an alteration of the oxygen vacancy concentration in the VO2 thin film. These results have significant impacts on technological applications for both passive and active devices by exploiting this near-room-temperature SMT. PMID:26884225

  6. Sports doping: emerging designer and therapeutic β2-agonists.

    PubMed

    Fragkaki, A G; Georgakopoulos, C; Sterk, S; Nielen, M W F

    2013-10-21

    Beta2-adrenergic agonists, or β2-agonists, are considered essential bronchodilator drugs in the treatment of bronchial asthma, both as symptom-relievers and, in combination with inhaled corticosteroids, as disease-controllers. The use of β2-agonists is prohibited in sports by the World Anti-Doping Agency (WADA) due to claimed anabolic effects, and also, is prohibited as growth promoters in cattle fattening in the European Union. This paper reviews the last seven-year (2006-2012) literature concerning the development of novel β2-agonists molecules either by modifying the molecule of known β2-agonists or by introducing moieties producing indole-, adamantyl- or phenyl urea derivatives. New emerging β2-agonists molecules for future therapeutic use are also presented, intending to emphasize their potential use for doping purposes or as growth promoters in the near future.

  7. Morphology Control and Photocatalysis Enhancement by in Situ Hybridization of Cuprous Oxide with Nitrogen-Doped Carbon Quantum Dots.

    PubMed

    Ma, Yujie; Li, Xiaolin; Yang, Zhi; Xu, Shusheng; Zhang, Wei; Su, Yanjie; Hu, Nantao; Lu, Weijie; Feng, Jie; Zhang, Yafei

    2016-09-20

    Cuprous oxide (Cu2O) is an attractive photocatalyst because of its visible-light-driven photocatalytic behavior, abundance, low toxicity, and environmental compatibility. However, its short electron diffusion length and low hole mobility result in low photocatalytic efficiency, which hinders its wider applications. Herein, we report an in situ method to introduce nitrogen-doped carbon dots (N-CDs) into Cu2O frameworks. It is interestingly found that the introduction of N-CDs drives the morphology of N-CDs/Cu2O to evolve from rough cube to sphere, and the most encouraging result is that all of the obtained N-CDs/Cu2O composites exhibit better photocatalytic activities than pure Cu2O cubes. The optimal N-CDs/Cu2O photocatalyst is synthesized with 10 mL of N-CDs solution, which shows the best degradation ability (100%, 70 min), far superior to pure Cu2O cubes (∼5%, 70 min) and P25 (∼10%, 70 min). Beside the photodegradation of methyl orange, N-CDs/Cu2O(10) composites also exhibit excellent photocatalytic activities in the photodegradation of methyl blue and rhodamine B. It is demonstrated that the excellent photocatalytic performance of N-CDs/Cu2O composites can be attributed to the highly roughened structure and the suppression of electron-hole recombination as a result of the introduction of N-CDs. These findings demonstrate that the conjugation of CDs is a promising method to improve the photocatalytic activities for traditional semiconductors.

  8. Morphology Control and Photocatalysis Enhancement by in Situ Hybridization of Cuprous Oxide with Nitrogen-Doped Carbon Quantum Dots.

    PubMed

    Ma, Yujie; Li, Xiaolin; Yang, Zhi; Xu, Shusheng; Zhang, Wei; Su, Yanjie; Hu, Nantao; Lu, Weijie; Feng, Jie; Zhang, Yafei

    2016-09-20

    Cuprous oxide (Cu2O) is an attractive photocatalyst because of its visible-light-driven photocatalytic behavior, abundance, low toxicity, and environmental compatibility. However, its short electron diffusion length and low hole mobility result in low photocatalytic efficiency, which hinders its wider applications. Herein, we report an in situ method to introduce nitrogen-doped carbon dots (N-CDs) into Cu2O frameworks. It is interestingly found that the introduction of N-CDs drives the morphology of N-CDs/Cu2O to evolve from rough cube to sphere, and the most encouraging result is that all of the obtained N-CDs/Cu2O composites exhibit better photocatalytic activities than pure Cu2O cubes. The optimal N-CDs/Cu2O photocatalyst is synthesized with 10 mL of N-CDs solution, which shows the best degradation ability (100%, 70 min), far superior to pure Cu2O cubes (∼5%, 70 min) and P25 (∼10%, 70 min). Beside the photodegradation of methyl orange, N-CDs/Cu2O(10) composites also exhibit excellent photocatalytic activities in the photodegradation of methyl blue and rhodamine B. It is demonstrated that the excellent photocatalytic performance of N-CDs/Cu2O composites can be attributed to the highly roughened structure and the suppression of electron-hole recombination as a result of the introduction of N-CDs. These findings demonstrate that the conjugation of CDs is a promising method to improve the photocatalytic activities for traditional semiconductors. PMID:27571475

  9. New oxymesterone metabolites in human by gas chromatography-tandem mass spectrometry and their application for doping control.

    PubMed

    Yang, Sheng; Lu, Jianghai; Xu, Youxuan; Wang, Xiaobing

    2016-07-01

    Oxymesterone (17α-methyl-4, 17β-dihydroxy-androst-4-ene-3-one) is one of the anabolic androgenic steroids (AAS) banned by the World Anti-Doping Agency (WADA). The biotransformation of oxymesterone is performed in vitro by human heptocytes and human urinary metabolic profiles are investigated after single dose of 20 mg to two adult males as well. Cell cultures and urine samples were hydrolyzed by β-glucuronidase, extracted, and reacted with N-Methyl-N-trimethylsilyltrifluoroacetamide (MSTFA), ammonium iodide (NH4 I), and dithioerythritol. After derivatization, a gas chromatography triple quadruple tandem mass spectrometry (GC-MS/MS) using full scan and MS/MS modes was applied. The total ion chromatographs of the blank and the positive samples are compared, and 7 new metabolites were found. In addition to the well-known 17-epioxymesterone, oxymesterone is metabolized by 4-ene-reduction, 3-keto-reduction, 11β-hydroxylation, and 16ξ-hydroxylation. Based on the behavior of the MS/MS results of product ion and precursor ion modes, a GC-MS/MS method has been developed monitoring these metabolites. The structures of metabolite 2 and 4 are tentatively identified as 17α-methyl-3β, 17β-dihydroxy-5α-androstane-4-one and 17α-methyl-3α, 4ξ, 17β-trihydroxy-5α-androstane, respectively. Detection of oxymesterone using new metabolites M2 and M4 can extend the detection window up to 4 days since the parent steroid was not detectable. Copyright © 2015 John Wiley & Sons, Ltd. PMID:26197789

  10. An Experimental Approach to Controllably Vary Protein Oxidation While Minimizing Electrode Adsorption for Boron-Doped Diamond Electrochemical Surface Mapping Applications

    PubMed Central

    McClintock, Carlee S; Hettich, Robert L.

    2012-01-01

    Oxidative protein surface mapping has become a powerful approach for measuring the solvent accessibility of folded protein structures. A variety of techniques exist for generating the key reagent – hydroxyl radicals – for these measurements; however, these approaches range significantly in their complexity and expense of operation. This research expands upon earlier work to enhance the controllability of boron-doped diamond (BDD) electrochemistry as an easily accessible tool for producing hydroxyl radicals in order to oxidize a range of intact proteins. Efforts to modulate oxidation level while minimizing the adsorption of protein to the electrode involved the use of relatively high flow rates to reduce protein residence time inside the electrochemical flow chamber. Additionally, a different cell activation approach using variable voltage to supply a controlled current allowed us to precisely tune the extent of oxidation in a protein-dependent manner. In order to gain perspective on the level of protein adsorption onto the electrode surface, studies were conducted to monitor protein concentration during electrolysis and gauge changes in the electrode surface between cell activation events. This report demonstrates the successful use of BDD electrochemistry for greater precision in generating a target number of oxidation events upon intact proteins. PMID:23210708

  11. Generation of Q-switched mode locking controlled rectangular noise-like soliton bunching in a Tm-doped fiber laser.

    PubMed

    Qiao, Tian; Chen, Weicheng; Lin, Wei; Yang, Zhongmin

    2016-08-01

    We report on an interesting phenomenon of the combination of Q-switched mode locked pulses (QSMLP) and rectangular noise-like pulses (RNLP) as a unit in a Tm-doped ring fiber laser which contains a Fabry-Perot (F-P) subcavity based on the nonlinear polarization evolution (NPE) technique. The RNLP and QSMLP are independently generated in the ring cavity and F-P subcavity, respectively. A notable characteristic is that the physical parameters of RNLP, e.g. repetition rate and pulse duration, are controlled by QSMLP. Thus, they form as a composite bunching, which is termed as "Q-switched mode locking controlled rectangular noise-like soliton bunching (QRNSB)". Further investigation shows that the existence of QRNSB only occurs in high pumping conditions, while both fundamental mode-locking pulses and the coexistence of QSMLP and solitons are achieved in low pumping ones. Our work can enrich the understanding of the nonlinear dynamics in fiber lasers. PMID:27505838

  12. Application of visible-light photocatalysis with nitrogen-doped or unmodified titanium dioxide for control of indoor-level volatile organic compounds.

    PubMed

    Jo, Wan-Kuen; Kim, Jong-Tae

    2009-05-15

    The present study evaluated visible-light photocatalysis, applying an annular reactor coated with unmodified or nitrogen (N)-doped titanium dioxide (TiO(2)), to cleanse gaseous volatile organic compounds (VOCs) at indoor levels. The surface chemistry investigation of N-doped TiO(2) suggested that there was no significant residual of sulfate ions or urea species on the surface of the N-doped TiO(2). Under visible-light irradiation, the photocatalytic technique using N-doped TiO(2) was much superior to that for unmodified TiO(2) for the degradation of VOCs. Moreover, the degradation efficiency by a reactor coated with N-doped TiO(2) was well above 90% for four target compounds (ethyl benzene, o,m,p-xylenes), suggesting that this photocatalytic system can be effectively employed to cleanse these pollutants at indoor air quality (IAQ) levels. The degradation efficiency of all target compounds increased as the stream flow rate (SFR) decreased. For most target compounds, a reactor with a lower hydraulic diameter (HD) exhibited elevated degradation efficiency. The result on humidity effect suggested that the N-doped photocatalyst could be employed effectively to remove four target compounds (ethyl benzene, o,m,p-xylenes) under conditions of less humidified environments, including a typical indoor comfort range (50-60%). Consequently, it is suggested that with appropriate photocatalytic conditions, a visible-light-assisted N-doped photocatalytic system is clearly an important tool for improving IAQ.

  13. Simultaneous size and luminescence control of NaYF4:Yb3+/RE3+ (RE = Tm, Ho) microcrystals via Li+ doping

    NASA Astrophysics Data System (ADS)

    Lin, Hao; Xu, Dekang; Teng, Dongdong; Yang, Shenghong; Zhang, Yueli

    2015-07-01

    Enhancement of upconversion (UC) luminescence is imperative for the applications of UC microcrystals (MCs). In this work, NaYF4:Yb3+/RE3+ (RE = Tm, Ho) MCs via Li+ doping were successfully prepared by a simple hydrothermal process with the assistance of citric acid. The UC luminescence intensities of NaYF4:Yb3+/RE3+ (RE = Tm, Ho) are significantly enhanced via Li+ doping at different concentrations. Compared to Li+-absent sample, UC luminescence intensities of blue emission (477 nm) and red emission (649 nm) in NaYF4:Yb3+/Tm3+ MCs via 15 mol% Li+ doping are improved by 10 and 9 times, respectively; UC luminescence intensities of green emission (538 nm) and red emission (644 nm) in NaYF4:Yb3+/Ho3+ MCs via 15 mol% Li+ doping are improved by 12 and 3 times, respectively. The mechanism of the enhancement via Li+ doping is discussed in details, which may be attributed to the fact that Li+ doping can cause the distortion of the local symmetry around RE ions. Our results indicate that the enhanced UC luminescence of NaYF4:Yb3+/RE3+ (RE = Tm, Ho) MCs via Li+ doping may have potential applications in optoelectronic devices such as solar cells and plasma display panel.

  14. Copper-Doped CdSe/ZnS Quantum Dots: Controllable Photoactivated Copper(I) Cation Storage and Release Vectors for Catalysis**

    PubMed Central

    Bear, Joseph C; Hollingsworth, Nathan; McNaughter, Paul D; Mayes, Andrew G; Ward, Michael B; Nann, Thomas; Hogarth, Graeme; Parkin, Ivan P

    2014-01-01

    The first photoactivated doped quantum dot vector for metal-ion release has been developed. A facile method for doping copper(I) cations within ZnS quantum dot shells was achieved through the use of metal-dithiocarbamates, with Cu+ ions elucidated by X-ray photoelectron spectroscopy. Photoexcitation of the quantum dots has been shown to release Cu+ ions, which was employed as an effective catalyst for the Huisgen [3+2] cycloaddition reaction. The relationship between the extent of doping, catalytic activity, and the fluorescence quenching was also explored. PMID:24376131

  15. Copper-doped CdSe/ZnS quantum dots: controllable photoactivated copper(I) cation storage and release vectors for catalysis.

    PubMed

    Bear, Joseph C; Hollingsworth, Nathan; McNaughter, Paul D; Mayes, Andrew G; Ward, Michael B; Nann, Thomas; Hogarth, Graeme; Parkin, Ivan P

    2014-02-01

    The first photoactivated doped quantum dot vector for metal-ion release has been developed. A facile method for doping copper(I) cations within ZnS quantum dot shells was achieved through the use of metal-dithiocarbamates, with Cu(+) ions elucidated by X-ray photoelectron spectroscopy. Photoexcitation of the quantum dots has been shown to release Cu(+) ions, which was employed as an effective catalyst for the Huisgen [3+2] cycloaddition reaction. The relationship between the extent of doping, catalytic activity, and the fluorescence quenching was also explored. PMID:24376131

  16. Comparison between triple quadrupole, time of flight and hybrid quadrupole time of flight analysers coupled to liquid chromatography for the detection of anabolic steroids in doping control analysis.

    PubMed

    Pozo, Oscar J; Van Eenoo, Peter; Deventer, Koen; Elbardissy, Hisham; Grimalt, Susana; Sancho, Juan V; Hernandez, Felix; Ventura, Rosa; Delbeke, Frans T

    2011-01-17

    Triple quadrupole (QqQ), time of flight (TOF) and quadrupole-time of flight (QTOF) analysers have been compared for the detection of anabolic steroids in human urine. Ten anabolic steroids were selected as model compounds based on their ionization and the presence of endogenous interferences. Both qualitative and quantitative analyses were evaluated. QqQ allowed for the detection of all analytes at the minimum required performance limit (MRPL) established by the World Anti-Doping Agency (between 2 and 10 ng mL(-1) in urine). TOF and QTOF approaches were not sensitive enough to detect some of the analytes (3'-hydroxy-stanozolol or the metabolites of boldenone and formebolone) at the established MRPL. Although a suitable accuracy was obtained, the precision was unsatisfactory (RSD typically higher than 20%) for quantitative purposes irrespective of the analyser used. The methods were applied to 30 real samples declared positives either for the misuse of boldenone, stanozolol and/or methandienone. Most of the compounds were detected by every technique, however QqQ was necessary for the detection of some metabolites in a few samples. Finally, the possibility to detect non-target steroids has been explored by the use of TOF and QTOF. The use of this approach revealed that the presence of boldenone and its metabolite in one sample was due to the intake of androsta-1,4,6-triene-3,17-dione. Additionally, the intake of methandienone was confirmed by the post-target detection of a long-term metabolite.

  17. Development and validation of a GC-C-IRMS method for the confirmation analysis of pseudo-endogenous glucocorticoids in doping control.

    PubMed

    de la Torre, Xavier; Curcio, Davide; Colamonici, Cristiana; Molaioni, Francesco; Cilia, Marta; Botrè, Francesco

    2015-01-01

    Glucocorticoids are included in the S9 section of the World Anti-doping Agency (WADA) prohibited list international standard. Some among them are pseudo-endogenous steroids, like cortisol and cortisone, which present the same chemical structure as endogenously produced steroids. We are proposing an analytical method based on gas chromatography coupled to isotope ratio mass spectrometry (GC-C-IRMS) which allows discrimination between endogenous and synthetic origin of the urinary metabolites of the pseudo-endogenous glucocorticoids. A preliminary purification treatment by high-performance liquid chromatography (HPLC) of the target compounds (TC) (i.e., cortisol, tetrahydrocortisone (THE) 5α-tetrahydrocortisone (aTHE), tetrahydrocortisol (THF), and 5α-tetrahydrocortisol (aTHF)) allows collection of extracts with adequate purity for the subsequent analysis by IRMS. A population of 40 urine samples was analyzed for the TC and for the endogenous reference compounds (ERC: i.e., 11-desoxy-tetrahydrocortisol (THS) or pregnanediol). For each sample, the difference between the delta values of the ERCs and TCs (Δδ values) were calculated and based on that, some decision limits for atypical findings are proposed. The limits are below 3% units except for cortisol. The fit to purpose of the method has been confirmed by the analysis of urine samples collected in two patients under treatment with 25 mg of cortisone acetate (p.o). The samples showed Δδ values higher than 3 for at least 24 h following administration depending on the TC considered. The method can easily be integrated into existing procedures already used for the HPLC purification and IRMS analysis of pseudo-endogenous steroids with androgenic/anabolic activity. PMID:26607312

  18. Examination of the kinetic isotopic effect to the acetylation derivatization for the gas chromatographic-combustion-isotope ratio mass spectrometric doping control analysis of endogenous steroids.

    PubMed

    Angelis, Yiannis S; Kioussi, Maroula K; Kiousi, Polyxeni; Brenna, J Thomas; Georgakopoulos, Costas G

    2012-12-01

    In gas chromatographic-combustion-isotope ratio mass spectrometry (GC-C-IRMS) doping control analysis, endogenous androgenic anabolic steroids and their metabolites are commonly acetylated using acetic anhydride reagent, thus incorporating exogenous carbon that contributes to the measured isotope ratio. Comparison of the endogenous δ(13)C of free, mono-, and di-acetylated steroids requires application of corrections, typically through straightforward use of the mass balance equation. Variability in kinetic isotope effects (KIE) due to steroid structures could cause fractionation of endogenous steroid carbon, resulting in inaccurate results. To test for possible KIE influence on δ(13)C, acetic anhydride of graded isotope ratio within the natural abundance range was used under normal derivatization conditions to test for linearity. In all cases, plots of measured steroid acetate δ(13)C versus acetic anhydride δ(13)C were linear and slopes were not significantly different. Regression analysis of the Δδ(13)C of enriched acetic anhydrides versus Δδ(13)C of derivatized steroids shows that KIE are similar in all cases. We conclude that δ(13)C calculated from the mass balance equation is independent of the δ(13)C of the acetic anhydride reagent, and that net KIE under normal derivatization conditions do not bias the final reported steroid δ(13)C.

  19. Deposition and composition-control of Mn-doped ZnO thin films by combinatorial pulsed laser deposition using two delayed plasma plumes

    SciTech Connect

    Sanchez-Ake, C.; Camacho, R.; Moreno, L.

    2012-08-15

    Thin films of ZnO doped with manganese were deposited by double-beam, combinatorial pulsed laser deposition. The laser-induced plasmas were studied by means of fast photography and using a Langmuir probe, whereas the films were analyzed by x-ray-diffraction and energy-dispersive x-ray spectroscopy. The effect of the relative delay between plasma plumes on the characteristics of the films was analyzed. It was found that using this parameter, it is possible to control the dopant content keeping the oriented wurtzite structure of the films. The minimum content of Mn was found for plume delays between 0 and 10 {mu}s as the interaction between plasmas scatters the dopant species away from the substrate, thus reducing the incorporation of Mn into the films. Results suggest that for delays shorter than {approx}100 {mu}s, the expansion of the second plume through the region behind the first plume affects the composition of the film.

  20. A Eu(3+)/Gd(3+)-EDTA-doped structurally controllable hollow mesoporous carbon for improving the oral bioavailability of insoluble drugs and in vivo tracing.

    PubMed

    Liu, Jia; Zhao, Yating; Cui, Yu; Yue, Yang; Gao, Yikun; Zhao, Qinfu; Liu, Jie; Wang, Siling

    2016-08-01

    A structurally controllable fluorescence-labeled hollow mesoporous carbon (HMC) was simply prepared to improve the oral bioavailability of insoluble drugs and further trace their delivery process in vivo. The hollow structure was derived from an inverse replica process using mesoporous silica as a template and the fluorescent label was prepared by doping the carboxylated HMC with a confinement of Eu(3+)/Gd(3+)-EDTA. The physicochemical properties of the composites were systematically characterized by transmission electron microscopy, Fourier transform infrared spectroscopy and photoluminescence spectra tests prior to studying their effects on drug-release behavior and biodistribution. As a result, the thickness of the carrier's shell was adjusted from 70 nm to 130 nm and the maximum drug loading was up to 73.6%. The model drug carvedilol (CAR) showed sustained release behavior compared to CAR commercial capsules, and the dissolution rate slowed down as the shells got thicker. AUC0-48h and Tmax were enlarged 2.2 and 6.5 fold, respectively, which demonstrated that oral bioavailability was successfully improved. Bioimaging tests showed that the novel carbon vehicle had a long residence time in the gastrointestinal tract. In short, the newly designed HMC is a promising drug carrier for both oral bioavailability improvement and in vivo tracing. PMID:27334550

  1. A Eu3+/Gd3+-EDTA-doped structurally controllable hollow mesoporous carbon for improving the oral bioavailability of insoluble drugs and in vivo tracing

    NASA Astrophysics Data System (ADS)

    Liu, Jia; Zhao, Yating; Cui, Yu; Yue, Yang; Gao, Yikun; Zhao, Qinfu; Liu, Jie; Wang, Siling

    2016-08-01

    A structurally controllable fluorescence-labeled hollow mesoporous carbon (HMC) was simply prepared to improve the oral bioavailability of insoluble drugs and further trace their delivery process in vivo. The hollow structure was derived from an inverse replica process using mesoporous silica as a template and the fluorescent label was prepared by doping the carboxylated HMC with a confinement of Eu3+/Gd3+-EDTA. The physicochemical properties of the composites were systematically characterized by transmission electron microscopy, Fourier transform infrared spectroscopy and photoluminescence spectra tests prior to studying their effects on drug-release behavior and biodistribution. As a result, the thickness of the carrier’s shell was adjusted from 70 nm to 130 nm and the maximum drug loading was up to 73.6%. The model drug carvedilol (CAR) showed sustained release behavior compared to CAR commercial capsules, and the dissolution rate slowed down as the shells got thicker. AUC0-48h and Tmax were enlarged 2.2 and 6.5 fold, respectively, which demonstrated that oral bioavailability was successfully improved. Bioimaging tests showed that the novel carbon vehicle had a long residence time in the gastrointestinal tract. In short, the newly designed HMC is a promising drug carrier for both oral bioavailability improvement and in vivo tracing.

  2. Deposition and composition-control of Mn-doped ZnO thin films by combinatorial pulsed laser deposition using two delayed plasma plumes

    NASA Astrophysics Data System (ADS)

    Sánchez-Aké, C.; Camacho, R.; Moreno, L.

    2012-08-01

    Thin films of ZnO doped with manganese were deposited by double-beam, combinatorial pulsed laser deposition. The laser-induced plasmas were studied by means of fast photography and using a Langmuir probe, whereas the films were analyzed by x-ray-diffraction and energy-dispersive x-ray spectroscopy. The effect of the relative delay between plasma plumes on the characteristics of the films was analyzed. It was found that using this parameter, it is possible to control the dopant content keeping the oriented wurtzite structure of the films. The minimum content of Mn was found for plume delays between 0 and 10 μs as the interaction between plasmas scatters the dopant species away from the substrate, thus reducing the incorporation of Mn into the films. Results suggest that for delays shorter than ˜100 μs, the expansion of the second plume through the region behind the first plume affects the composition of the film.

  3. In situ control of local pH using a boron doped diamond ring disk electrode: optimizing heavy metal (mercury) detection.

    PubMed

    Read, Tania L; Bitziou, Eleni; Joseph, Maxim B; Macpherson, Julie V

    2014-01-01

    A novel electrochemical approach to modifying aqueous solution pH in the vicinity of a detector electrode in order to optimize the electrochemical measurement signal is described. A ring disk electrode was employed where electrochemical decomposition of water on the ring was used to generate a flux of protons which adjusts the local pH controllably and quantifiably at the disk. Boron doped diamond (BDD) functioned as the electrode material given the stability of this electrode surface especially when applying high potentials (to electrolyze water) for significant periods of time. A pH sensitive iridium oxide electrode electrodeposited on the disk electrode demonstrated that applied positive currents on the BDD ring, up to +50 μA, resulted in a local pH decrease of over 4 orders of magnitude, which remained stable over the measurement time of 600 s. pH generation experiments were found to be in close agreement with finite element simulations. The dual electrode arrangement was used to significantly improve the stripping peak signature for Hg in close to neutral conditions by the generation of pH = 2.0, locally. With the ability to create a localized pH change electrochemically in the vicinity of the detector electrode, this system could provide a simple method for optimized analysis at the source, e.g., river and sea waters. PMID:24321045

  4. Large-Scale Synthesis of Transition-Metal-Doped TiO2 Nanowires with Controllable Overpotential

    SciTech Connect

    Liu, Bin; Chen, HaoMing; Liu, Chong; Andrews, Sean; Han, Chris; Yang, Peidong

    2013-03-13

    Practical implementation of one-dimensional semiconductors into devices capable of exploiting their novel properties is often hindered by low product yields, poor material quality, high production cost, or overall lack of synthetic control. Here, we show that a molten-salt flux scheme can be used to synthesize large quantities of high-quality, single-crystalline TiO2 nanowires with controllable dimensions. Furthermore, in situ dopant incorporation of various transition metals allows for the tuning of optical, electrical, and catalytic properties. With this combination of control, robustness, and scalability, the molten-salt flux scheme can provide high-quality TiO2 nanowires to satisfy a broad range of application needs from photovoltaics to photocatalysis.

  5. Single Schottky junction FETs based on Si:P nanowires with axially graded doping

    NASA Astrophysics Data System (ADS)

    Barreda, Jorge; Keiper, Timothy; Zhang, Mei; Xiong, Peng

    2015-03-01

    Si nanowires (NWs) with a systematic axial increase in phosphorus doping have been synthesized via a vapor-liquid-solid method. Silane and phosphine precursor gases are utilized for the growth and doping, respectively. The phosphorous doping profile is controlled by the flow ratio of the precursor gases. After the as-grown product is ultrasonically agitated into a solution, the Si NWs are dispersed on a SiO2 substrate with a highly doped Si back gate. Individual NWs are identified for the fabrication of field-effect transistors (FETs) with multiple Cr/Ag contacts along the NW. Two-probe and four-probe measurements are taken systematically under vacuum conditions at room temperature and the contribution from each contact and each NW section between adjacent contacts is determined. The graded doping level, produced by a systematic reduction in dopant density along the length of the NWs, is manifested in the regular increases in the channel and contact resistances. Our Si NWs facilitate the fabrication of asymmetric FETs with one ohmic and one Schottky contact. A significant increase in gate modulation is obtained due to the single Schottky-barrier contact. Characterization details and the applicability for sensing purposes will be discussed.

  6. The effect of the dopant nature on the reactivity, interlayer bonding and electronic properties of dual doped bilayer graphene.

    PubMed

    Denis, Pablo A; Iribarne, Federico

    2016-09-21

    Herein, we report on the structural, chemical reactivity and electronic properties of dual-doped bilayer graphene (DDBG). Only one of the layers was doped with a pair of 3p-2p elements. Aluminum was the only dopant which prefers to interact with the undoped layer. The interlayer interaction energies of DDBG are smaller than those determined for bilayer graphene, except for AlN and AlO DDBG. This effect is due to the presence of weak Al-C interlayer bonds. The dopants increase the reactivity of both the doped and undoped layers. Interestingly, we found that hydrogenation is a method that can be used to switch on/off the interlayer bonding, as it controlled the X-C interlayer distance (X = Al, Si, P, S). The magnetic moment of the systems can be adjusted by the position of the 3p dopant. In effect, when X interacts with the doped layer, the magnetic moment is reduced, while it is maintained when X fails to interact. Finally, we found that the doped layer is able to break the symmetry of the undoped sheet and small gaps can be opened in the band structure of the undoped layer. As observed for single doped monolayer graphene, the most effective element for such purposes is P, which opened gaps close to 0.2 eV. For SiN DDBG, the spin filtering properties are enhanced with respect to the monolayered structure. PMID:27545204

  7. Morphology-controlled synthesis of Ti{sup 3+} self-doped yolk–shell structure titanium oxide with superior photocatalytic activity under visible light

    SciTech Connect

    Wang, Shixiong; Yang, Xiangjun; Wang, Yapeng; Liu, Lixiang; Guo, Yuanyuan; Guo, Hong

    2014-05-01

    Ti{sup 3+} self-doped yolk–shell structure titanium oxide nanoparticle aggregates are fabricated through an environmental template-free route and the reduction reaction at low temperature subsequently. After the Ti{sup 3+} doping, the reduced TiO{sub 2} sample exhibits a wide visible-light absorption ranged from 400 nm to 800 nm. The intrinsic hollow core–shell microstructure can make multiple reflections of light within the chamber, and thus results in more efficient use of the light source compared with solid structure. Besides, the large surface area can render the sample with a high activity. Therefore, Ti{sup 3+} self-doped yolk–shell structure titanium oxide exhibits a superior photocatalytic activity under visible light. This strategy is simple, cheap and mass-productive, which may shed light on a new avenue for large scale production of self-doped yolk–shell structural nano functional materials for catalyst, sensors, energy storage and other new applications. - Graphical abstract: A facile generic strategy is employed to prepare Ti{sup 3+} self-doped yolk–shell structure titanium oxide nanoparticle aggregates with the superior photocatalytic activity under visible light. - Highlights: • Yolk–shell TiO{sub 2} mesospheres are synthesized by solvothermal alcoholysis. • Ti{sup 3+} self-doped yolk–shell structure titanium oxide is obtained at low temperature. • It exhibits a remarkable photocatalytic activity.

  8. [Doping, sport and addiction--any links?].

    PubMed

    Foucart, J; Verbanck, P; Lebrun, P

    2015-01-01

    Sport is widely encouraged as it is beneficial for health. However, high-performance sport is more and more associated to rather suspicious practices; doping is one of the best example. From a physician point of view, the use of doping agents is obviously a major concern because taking such products often induce serious adverse effects on health. The present manuscript aims to inform physicians about the most frequent doping practices. It also points out that intensive sport can generate an "addictive" behavior sharing with "common"addictions a loss of practice control, a lack of interest in other activities and even a sport's practice detrimental to athlete's health. Analysis of the doping issue needs to take this reality into account as some doping products display an established " addictive" effect.

  9. Sub-10 nm lanthanide doped BaLuF{sub 5} nanocrystals: Shape controllable synthesis, tunable multicolor emission and enhanced near-infrared upconversion luminescence

    SciTech Connect

    Rao, Ling; Lu, Wei; Wang, Haibo; Yi, Zhigao; Zeng, Songjun; Li, Zheng

    2015-04-15

    Highlights: • Sub-10 nm cubic phase BaLuF{sub 5} nanocrystals were synthesized by a hydrothermal method for the first time. • Tunable multicolor from yellow to yellow-green was achieved by controlling Gd{sup 3+} content in BaLuF{sub 5}:Yb/Er system. • Intense near-infrared upconversion luminescence in BaLuF{sub 5}:Gd/Yb/Tm nanocrystal. • The enhancement near-infrared luminescence can be realized by adjusting the content of Gd{sup 3+} in BaLuF{sub 5}:Gd/Yb/Tm system. - Abstract: In this study, sub-10 nm BaLuF{sub 5} nanocrystals with cubic phase structure were synthesized by a solvothermal method using oleic acid as the stabilizing agent. The as-prepared BaLuF{sub 5} nanocrystals were characterized by transmission electron microscopy (TEM), X-ray diffraction (XRD), and analyzed by the upconversion (UC) spectra. The TEM results reveal that these samples present high uniformity. Compared with Gd-free samples, the size of BaLuF{sub 5}:Yb/Er doped with 10% Gd{sup 3+} decreased to 5.6 nm. In addition, BaLuF{sub 5}:Yb/Tm/Gd upconversion nanoparticles (UCNPs) presented efficient near-infrared (NIR)-NIR UC luminescence. Therefore, it is expected that these ultra-small BaLuF{sub 5} nanocrystals with well-controlled shape, size, and UC emission have potential applications in biomedical imaging fields.

  10. Networks of superconducting nano-puddles in 1/8 doped YBa2Cu3O6.5 + y controlled by thermal manipulation

    NASA Astrophysics Data System (ADS)

    Ricci, Alessandro; Poccia, Nicola; Campi, Gaetano; Coneri, Francesco; Barba, Luisa; Arrighetti, Gianmichele; Polentarutti, Maurizio; Burghammer, Manfred; Sprung, Michael; Zimmermann, Martin v.; Bianconi, Antonio

    2014-05-01

    While it is known that the nature and the arrangement of defects in complex oxides have an impact on the material functionalities, little is known about control of superconductivity by oxygen interstitial organization in cuprates. Here we report direct compelling evidence for the control of T c by manipulation of the superconducting granular networks of nanoscale puddles, made of ordered oxygen stripes, in a single crystal of YBa2Cu3O6.5 + y with average formal hole doping p close to 1/8. Upon thermal treatments we were able to switch from a first network of oxygen defect striped puddles with OVIII modulation (q OVIII(a*) = (h + 3/8, k, 0) and q OVIII(a*) = (h + 5/8, k, 0)) to a second network characterized by OXVI modulation (q OXVI(a*) = (h + 7/16, k, 0) and qox-VI(a*) = (h + 9/16, k, 0)) and finally to a third network with puddles of OV periodicity (q OV(a*) = (4/10, 1, 0) and q OV(a*) = (6/10, 1, 0)). We map the microscopic spatial evolution of the out of plane OVIII, OXVI and OV puddle nano-size distribution via scanning micro-diffraction measurements. In particular, we calculated the number of oxygen chains (n) and the charge density (hole concentration p) inside each puddle, analyzing areas of 160 × 80 μm2, and recording 12 800 diffraction patterns to reconstruct each spatial map. The high spatial inhomogeneity shown by all the reconstructed spatial maps reflects the intrinsic granular structure that characterizes cuprates and iron chalcogenides, disclosing the presence of several complex networks of coexisting superconducting domains with different lattice modulations, charge densities and gaps as in the proposed multi-gap scenario called superstripes.

  11. Validation of a GC/MS method for the detection of two quinolinone-derived selective androgen receptor modulators in doping control analysis.

    PubMed

    Gerace, E; Salomone, A; Fasano, F; Costa, R; Boschi, D; Di Stilo, A; Vincenti, M

    2011-04-01

    Selective androgen receptor modulators (SARMs) represent an emerging class of drugs likely to be abused in sport. For clinical applications, these substances provide a promising alternative to testosterone-replacement therapies and their advantages include oral bioavailability, androgen receptor specificity, tissue selectivity, and the absence of steroid-related side effects. Although not yet commercially available, since January 2008 SARMs have been included on the prohibited list issued yearly by the World Anti-Doping Agency (WADA), so control laboratories need to update their procedures to detect either the parent drugs or their metabolites. Within this context, two quinolinone SARM models were synthesized and automatically characterized to update the existing routine screening procedures. The conditions for the new target analytes are compatible with the existing laboratory protocols used for both in-competition and out-of-competition controls and can be included in them. Validation parameters according to ISO 17025 and WADA guidelines were successfully determined. For analytical determinations, spiked urine samples were hydrolyzed and extracted at pH 9.6 with 10 mL of tert-butyl methyl ether. Then, the analytes were subsequently converted into trimethylsilyl derivatives and detected by gas chromatography-mass spectrometry. The absence of interferents, together with excellent repeatability of both retention times and the relative abundances of diagnostic ions, allowed proper identification of all SARM analytes. The analytes' quantification was linear up to 500 ng/mL and precision criteria were satisfied (coefficient of variation less than 25% at 10 ng/mL). The limits of detection were 1 ng/mL for both SARMs, whereas recovery values were between 95.5 and 99.3%. The validated method can be efficiently used for urine screening of the 2-quinolinone-derived SARMs tested.

  12. FIFA's approach to doping in football

    PubMed Central

    Dvorak, J; Graf‐Baumann, T; D'Hooghe, M; Kirkendall, D; Taennler, H; Saugy, M

    2006-01-01

    Background and objectives FIFA's anti‐doping strategy relies on education and prevention. A worldwide network of physicians guarantees doping control procedures that are straightforward and leave no place for cheating. FIFA actively acknowledges its responsibility to protect players from harm and ensure equal chances for all competitors by stringent doping control regulations, data collection of positive samples, support of research, and collaboration with other organisations. This article aims to outline FIFA's approach to doping in football. Method Description of FIFA's doping control regulations and procedures, statistical analysis of FIFA database on doping control, and comparison with data obtained by WADA accredited laboratories as for 2004. Results Data on positive doping samples per substance and confederation/nation documented at the FIFA medical office from 1994 to 2005 are provided. According to the FIFA database, the incidence of positive cases over the past 11 years was 0.12%, with about 0.42% in 2004 (based on the assumption of 20 750 samples per year) and 0.37% in 2005. Especially important in this regard is the extremely low incidence of the true performance enhancing drugs such as anabolic steroids and stimulants. However, there is a need for more consistent data collection and cross checks among international anti‐doping agencies as well as for further studies on specific substances, methods, and procedures. With regard to general health impairments in players, FIFA suggests that principles of occupational medicine should be considered and treatment with banned substances for purely medical reasons should be permitted to enable players to carry out their profession. At the same time, a firm stand has to be taken against suppression of symptoms by medication with the aim of meeting the ever increasing demands on football players. Conclusion Incidence of doping in football seems to be low, but much closer collaboration and further

  13. Doping and musculoskeletal system: short-term and long-lasting effects of doping agents.

    PubMed

    Nikolopoulos, Dimitrios D; Spiliopoulou, Chara; Theocharis, Stamatios E

    2011-10-01

    Doping is a problem that has plagued the world of competition and sports for ages. Even before the dawn of Olympic history in ancient Greece, competitors have looked for artificial means to improve athletic performance. Since ancient times, athletes have attempted to gain an unfair competitive advantage through the use of doping substances. A Prohibited List of doping substances and methods banned in sports is published yearly by the World Anti-Doping Agency. Among the substances included are steroidal and peptide hormones and their modulators, stimulants, glucocorticosteroids, β₂-agonists, diuretics and masking agents, narcotics, and cannabinoids. Blood doping, tampering, infusions, and gene doping are examples of prohibited methods indicated on the List. Apart from the unethical aspect of doping, as it abrogates fair-play's principle, it is extremely important to consider the hazards it presents to the health and well-being of athletes. The referred negative effects for the athlete's health have to do, on the one hand, by the high doses of the performance-enhancing agents and on the other hand, by the relentless, superhuman strict training that the elite or amateur athletes put their muscles, bones, and joints. The purpose of this article is to highlight the early and the long-lasting consequences of the doping abuse on bone and muscle metabolism.

  14. Controlled agglomeration of Tb-doped Y{sub 2}O{sub 3} nanocrystals studied by x-ray absorption fine structure, x-ray excited luminescence, and photoluminescence

    SciTech Connect

    Soo, Y.L.; Huang, S.W.; Kao, Y.H.; Chhabra, V.; Kulkarni, B.; Veliadis, J.V.; Bhargava, R.N.

    1999-10-01

    Local environment surrounding Y atoms in Y{sub 2}O{sub 3}:Tb nanocrystals under various heat treatment conditions has been investigated by using the extended x-ray absorption fine structure (EXAFS) technique. X-ray excited luminescence (XEL) with the incident x-ray energy near Y {ital K} edge and Tb {ital L} edges has also been measured to investigate the mechanisms of x-ray-to-visible down conversion in these doped nanoparticles. The observed changes in EXAFS, XEL, and photoluminescent data can be explained on the basis of increased average size of the nanoparticles as confirmed by transmission electron microscopy studies. Our results thus demonstrate that the doped nanoparticles can agglomerate to a controllable degree by varying the heat treatment temperature. At higher temperatures, the local environment surrounding Y atoms in the nanoparticles is found to become similar to that in bulk Y{sub 2}O{sub 3} while the XEL output still shows the characteristics of nanocrystals. These results indicate that appropriate heat treatment can afford an effective means to control the intensity and signal-to-background ratio of green luminescence output of these doped nanocrystal phosphors, potentially useful for some device applications. {copyright} {ital 1999 American Institute of Physics.}

  15. Nanophotonics and nanochemistry: controlling the excitation dynamics for frequency up- and down-conversion in lanthanide-doped nanoparticles.

    PubMed

    Chen, Guanying; Yang, Chunhui; Prasad, Paras N

    2013-07-16

    Nanophotonics is an emerging science dealing with the interaction of light and matter on a nanometer scale and holds promise to produce new generation nanophosphors with highly efficient frequency conversion of infrared (IR) light. Scientists can control the excitation dynamics by using nanochemistry to produce hierarchically built nanostructures and tailor their interfaces. These nanophosphors can either perform frequency up-conversion from IR to visible or ultraviolet (UV) or down-conversion, which results in the IR light being further red shifted. Nanophotonics and nanochemistry open up numerous opportunities for these photon converters, including in high contrast bioimaging, photodynamic therapy, drug release and gene delivery, nanothermometry, and solar cells. Applications of these nanophosphors in these directions derive from three main stimuli. Light excitation and emission within the near-infrared (NIR) "optical transparency window" of tissues is ideal for high contrast in vitro and in vivo imaging. This is due to low natural florescence, reduced scattering background, and deep penetration in tissues. Secondly, the naked eye is highly sensitive in the visible range, but it has no response to IR light. Therefore, many scientists have interest in the frequency up-conversion of IR wavelengths for security and display applications. Lastly, frequency up-conversion can convert IR photons to higher energy photons, which can then readily be absorbed by solar materials. Current solar devices do not use abundant IR light that comprises almost half of solar energy. In this Account, we present our recent work on nanophotonic control of frequency up- and down-conversion in fluoride nanophosphors, and their biophotonic and nanophotonic applications. Through nanoscopic control of phonon dynamics, electronic energy transfer, local crystal field, and surface-induced non-radiative processes, we were able to produce new generation nanophosphors with highly efficient frequency

  16. Nucleation control for large, single crystalline domains of monolayer hexagonal boron nitride via Si-doped Fe catalysts.

    PubMed

    Caneva, Sabina; Weatherup, Robert S; Bayer, Bernhard C; Brennan, Barry; Spencer, Steve J; Mingard, Ken; Cabrero-Vilatela, Andrea; Baehtz, Carsten; Pollard, Andrew J; Hofmann, Stephan

    2015-03-11

    The scalable chemical vapor deposition of monolayer hexagonal boron nitride (h-BN) single crystals, with lateral dimensions of ∼0.3 mm, and of continuous h-BN monolayer films with large domain sizes (>25 μm) is demonstrated via an admixture of Si to Fe catalyst films. A simple thin-film Fe/SiO2/Si catalyst system is used to show that controlled Si diffusion into the Fe catalyst allows exclusive nucleation of monolayer h-BN with very low nucleation densities upon exposure to undiluted borazine. Our systematic in situ and ex situ characterization of this catalyst system establishes a basis for further rational catalyst design for compound 2D materials.

  17. Nucleation Control for Large, Single Crystalline Domains of Monolayer Hexagonal Boron Nitride via Si-Doped Fe Catalysts

    PubMed Central

    2015-01-01

    The scalable chemical vapor deposition of monolayer hexagonal boron nitride (h-BN) single crystals, with lateral dimensions of ∼0.3 mm, and of continuous h-BN monolayer films with large domain sizes (>25 μm) is demonstrated via an admixture of Si to Fe catalyst films. A simple thin-film Fe/SiO2/Si catalyst system is used to show that controlled Si diffusion into the Fe catalyst allows exclusive nucleation of monolayer h-BN with very low nucleation densities upon exposure to undiluted borazine. Our systematic in situ and ex situ characterization of this catalyst system establishes a basis for further rational catalyst design for compound 2D materials. PMID:25664483

  18. Obtaining strong ferromagnetism in diluted Gd-doped ZnO thin films through controlled Gd-defect complexes

    SciTech Connect

    Roqan, I. S. Venkatesh, S.; Zhang, Z.; Hussain, S.; Bantounas, I.; Flemban, T. H.; Schwingenschlogl, U.; Franklin, J. B.; Zou, B.; Petrov, P. K.; Ryan, M. P.; Alford, N. M.; Lee, J.-S.

    2015-02-21

    We demonstrate the fabrication of reproducible long-range ferromagnetism (FM) in highly crystalline Gd{sub x}Zn{sub 1−x}O thin films by controlling the defects. Films are grown on lattice-matched substrates by pulsed laser deposition at low oxygen pressures (≤25 mTorr) and low Gd concentrations (x ≤ 0.009). These films feature strong FM (10 μ{sub B} per Gd atom) at room temperature. While films deposited at higher oxygen pressure do not exhibit FM, FM is recovered by post-annealing these films under vacuum. These findings reveal the contribution of oxygen deficiency defects to the long-range FM. We demonstrate the possible FM mechanisms, which are confirmed by density functional theory study, and show that Gd dopants are essential for establishing FM that is induced by intrinsic defects in these films.

  19. 23 CFR 650.201 - Purpose.

    Code of Federal Regulations, 2011 CFR

    2011-04-01

    ..., STRUCTURES, AND HYDRAULICS Erosion and Sediment Control on Highway Construction Projects § 650.201 Purpose. The purpose of this subpart is to prescribe policies and procedures for the control of...

  20. 23 CFR 650.201 - Purpose.

    Code of Federal Regulations, 2014 CFR

    2014-04-01

    ..., STRUCTURES, AND HYDRAULICS Erosion and Sediment Control on Highway Construction Projects § 650.201 Purpose. The purpose of this subpart is to prescribe policies and procedures for the control of...

  1. 23 CFR 650.201 - Purpose.

    Code of Federal Regulations, 2013 CFR

    2013-04-01

    ..., STRUCTURES, AND HYDRAULICS Erosion and Sediment Control on Highway Construction Projects § 650.201 Purpose. The purpose of this subpart is to prescribe policies and procedures for the control of...

  2. 23 CFR 650.201 - Purpose.

    Code of Federal Regulations, 2012 CFR

    2012-04-01

    ..., STRUCTURES, AND HYDRAULICS Erosion and Sediment Control on Highway Construction Projects § 650.201 Purpose. The purpose of this subpart is to prescribe policies and procedures for the control of...

  3. 23 CFR 650.201 - Purpose.

    Code of Federal Regulations, 2010 CFR

    2010-04-01

    ..., STRUCTURES, AND HYDRAULICS Erosion and Sediment Control on Highway Construction Projects § 650.201 Purpose. The purpose of this subpart is to prescribe policies and procedures for the control of...

  4. 46 CFR Sec. 1 - Purpose.

    Code of Federal Regulations, 2011 CFR

    2011-10-01

    ... 46 Shipping 8 2011-10-01 2011-10-01 false Purpose. Sec. 1 Section 1 Shipping MARITIME ADMINISTRATION, DEPARTMENT OF TRANSPORTATION B-CONTROL AND UTILIZATION OF PORTS OPERATING CONTRACT Sec. 1 Purpose. This part prescribes the standard form of marine terminal contract to be entered into by the...

  5. New drostanolone metabolites in human urine by liquid chromatography time-of-flight tandem mass spectrometry and their application for doping control.

    PubMed

    Liu, Yang; Lu, Jianghai; Yang, Sheng; Zhang, Qingying; Xu, Youxuan

    2016-04-01

    Drostanolone is one of the most frequently detected anabolic androgenic steroids in doping control analysis. Here, we studied drostanolone urinary metabolic profiles using liquid chromatography quadruple time of flight mass spectrometry (LC-QTOF-MS) in full scan and targeted MS/MS modes with accurate mass measurement. The drug was administered to one healthy male volunteer and liquid-liquid extraction along with direct-injection were used to analyze urine samples. Chromatographic peaks for potential metabolites were identified with the theoretical [M-H](-) as a target ion in a full scan experiment and actual deprotonated ions were analyzed in targeted MS/MS mode. Eleven metabolites including five new sulfates, five glucuronide conjugates, and one free metabolite were confirmed for drostanolone. Due to the absence of useful fragment ions to illustrate the steroid ring structure of drostanolone phase II metabolites, gas chromatography mass spectrometry (GC-MS) was used to obtain structural details of the trimethylsilylated phase I metabolite released after enzymatic hydrolysis and a potential structure was proposed using a combined MS approach. Metabolite detection times were recorded and S4 (2α-methyl-5α-androstan-17-one-6β-ol-3α-sulfate) and G1 (2α-methyl-5α-androstan-17-one-3α-glucuronide) were thought to be new potential biomarkers for drostanolone misuse which can be detected up to 24days by liquid-liquid extraction and 7days by direct-injection analysis after intramuscular injection. S4 and G1 were also detected in two drostanolone-positive routine urine samples. PMID:26826321

  6. Doping of graphene during chemical exfoliation

    NASA Astrophysics Data System (ADS)

    Srivastava, Pawan Kumar; Yadav, Premlata; Ghosh, Subhasis

    2013-02-01

    Graphene provides a perfect platform to explore the unique electronic properties in two-dimensions. However, most electronic applications are handicapped by the absence of a semiconducting gap in pristine graphene. To control the semiconducting properties of graphene, doping is regarded as one of the most feasible methods. Here we demonstrate that graphene can be effectively doped during chemical exfoliation of highly ordered pyrolitic graphite in organic solvents. Layered structure of graphene sheets was confirmed by confocal Raman spectroscopy and doping was probed by analyzing shift in Raman peak positions and transistor transfer (IDS-VGS) characteristics.

  7. Controlled cobalt doping in the spinel structure of magnetosome magnetite: new evidences from element- and site-specific X-ray magnetic circular dichroism analyses.

    PubMed

    Li, Jinhua; Menguy, Nicolas; Arrio, Marie-Anne; Sainctavit, Philippe; Juhin, Amélie; Wang, Yinzhao; Chen, Haitao; Bunau, Oana; Otero, Edwige; Ohresser, Philippe; Pan, Yongxin

    2016-08-01

    The biomineralization of magnetite nanocrystals (called magnetosomes) by magnetotactic bacteria (MTB) has attracted intense interest in biology, geology and materials science due to the precise morphology of the particles, the chain-like assembly and their unique magnetic properties. Great efforts have been recently made in producing transition metal-doped magnetosomes with modified magnetic properties for a range of applications. Despite some successful outcomes, the coordination chemistry and magnetism of such metal-doped magnetosomes still remain largely unknown. Here, we present new evidences from X-ray magnetic circular dichroism (XMCD) for element- and site-specific magnetic analyses that cobalt is incorporated in the spinel structure of the magnetosomes within Magnetospirillum magneticum AMB-1 through the replacement of Fe(2+) ions by Co(2+) ions in octahedral (Oh) sites of magnetite. Both XMCD at Fe and Co L2,3 edges, and energy-dispersive X-ray spectroscopy on transmission electron microscopy analyses reveal a heterogeneous distribution of cobalt occurring either in different particles or inside individual particles. Compared with non-doped one, cobalt-doped magnetosome sample has lower Verwey transition temperature and larger magnetic coercivity, related to the amount of doped cobalt. This study also demonstrates that the addition of trace cobalt in the growth medium can significantly improve both the cell growth and the magnetosome formation within M. magneticum AMB-1. Together with the cobalt occupancy within the spinel structure of magnetosomes, this study indicates that MTB may provide a promising biomimetic system for producing chains of metal-doped single-domain magnetite with an appropriate tuning of the magnetic properties for technological and biomedical applications. PMID:27512138

  8. Controlled cobalt doping in the spinel structure of magnetosome magnetite: new evidences from element- and site-specific X-ray magnetic circular dichroism analyses.

    PubMed

    Li, Jinhua; Menguy, Nicolas; Arrio, Marie-Anne; Sainctavit, Philippe; Juhin, Amélie; Wang, Yinzhao; Chen, Haitao; Bunau, Oana; Otero, Edwige; Ohresser, Philippe; Pan, Yongxin

    2016-08-01

    The biomineralization of magnetite nanocrystals (called magnetosomes) by magnetotactic bacteria (MTB) has attracted intense interest in biology, geology and materials science due to the precise morphology of the particles, the chain-like assembly and their unique magnetic properties. Great efforts have been recently made in producing transition metal-doped magnetosomes with modified magnetic properties for a range of applications. Despite some successful outcomes, the coordination chemistry and magnetism of such metal-doped magnetosomes still remain largely unknown. Here, we present new evidences from X-ray magnetic circular dichroism (XMCD) for element- and site-specific magnetic analyses that cobalt is incorporated in the spinel structure of the magnetosomes within Magnetospirillum magneticum AMB-1 through the replacement of Fe(2+) ions by Co(2+) ions in octahedral (Oh) sites of magnetite. Both XMCD at Fe and Co L2,3 edges, and energy-dispersive X-ray spectroscopy on transmission electron microscopy analyses reveal a heterogeneous distribution of cobalt occurring either in different particles or inside individual particles. Compared with non-doped one, cobalt-doped magnetosome sample has lower Verwey transition temperature and larger magnetic coercivity, related to the amount of doped cobalt. This study also demonstrates that the addition of trace cobalt in the growth medium can significantly improve both the cell growth and the magnetosome formation within M. magneticum AMB-1. Together with the cobalt occupancy within the spinel structure of magnetosomes, this study indicates that MTB may provide a promising biomimetic system for producing chains of metal-doped single-domain magnetite with an appropriate tuning of the magnetic properties for technological and biomedical applications.

  9. 40 CFR 35.570 - Purpose.

    Code of Federal Regulations, 2010 CFR

    2010-07-01

    ... ASSISTANCE Environmental Program Grants for Tribes Air Pollution Control (section 105) § 35.570 Purpose. (a) Purpose of section. Sections 35.570 through 35.578 govern air pollution control grants to Tribes (as... and Intertribal Consortia. (b) Purpose of program. Air pollution control grants are awarded to...

  10. 40 CFR 35.160 - Purpose.

    Code of Federal Regulations, 2012 CFR

    2012-07-01

    ... ASSISTANCE Environmental Program Grants Water Pollution Control (section 106) § 35.160 Purpose. (a) Purpose of section. Sections 35.160 through 35.168 govern Water Pollution Control Grants to State and... Clean Water Act. (b) Purpose of program. Water Pollution Control Grants are awarded to assist...

  11. 40 CFR 35.580 - Purpose.

    Code of Federal Regulations, 2011 CFR

    2011-07-01

    ... ASSISTANCE Environmental Program Grants for Tribes Water Pollution Control (sections 106 and 518) § 35.580 Purpose. (a) Purpose of section. Sections 35.580 through 35.588 govern water pollution control grants to... the Clean Water Act. (b) Purpose of program. Water pollution control grants are awarded to...

  12. 40 CFR 35.160 - Purpose.

    Code of Federal Regulations, 2014 CFR

    2014-07-01

    ... ASSISTANCE Environmental Program Grants Water Pollution Control (section 106) § 35.160 Purpose. (a) Purpose of section. Sections 35.160 through 35.168 govern Water Pollution Control Grants to State and... Clean Water Act. (b) Purpose of program. Water Pollution Control Grants are awarded to assist...

  13. 40 CFR 35.160 - Purpose.

    Code of Federal Regulations, 2013 CFR

    2013-07-01

    ... ASSISTANCE Environmental Program Grants Water Pollution Control (section 106) § 35.160 Purpose. (a) Purpose of section. Sections 35.160 through 35.168 govern Water Pollution Control Grants to State and... Clean Water Act. (b) Purpose of program. Water Pollution Control Grants are awarded to assist...

  14. 40 CFR 35.580 - Purpose.

    Code of Federal Regulations, 2013 CFR

    2013-07-01

    ... ASSISTANCE Environmental Program Grants for Tribes Water Pollution Control (sections 106 and 518) § 35.580 Purpose. (a) Purpose of section. Sections 35.580 through 35.588 govern water pollution control grants to... the Clean Water Act. (b) Purpose of program. Water pollution control grants are awarded to...

  15. 40 CFR 35.160 - Purpose.

    Code of Federal Regulations, 2010 CFR

    2010-07-01

    ... ASSISTANCE Environmental Program Grants Water Pollution Control (section 106) § 35.160 Purpose. (a) Purpose of section. Sections 35.160 through 35.168 govern Water Pollution Control Grants to State and... Clean Water Act. (b) Purpose of program. Water Pollution Control Grants are awarded to assist...

  16. 40 CFR 35.580 - Purpose.

    Code of Federal Regulations, 2014 CFR

    2014-07-01

    ... ASSISTANCE Environmental Program Grants for Tribes Water Pollution Control (sections 106 and 518) § 35.580 Purpose. (a) Purpose of section. Sections 35.580 through 35.588 govern water pollution control grants to... the Clean Water Act. (b) Purpose of program. Water pollution control grants are awarded to...

  17. 40 CFR 35.580 - Purpose.

    Code of Federal Regulations, 2010 CFR

    2010-07-01

    ... ASSISTANCE Environmental Program Grants for Tribes Water Pollution Control (sections 106 and 518) § 35.580 Purpose. (a) Purpose of section. Sections 35.580 through 35.588 govern water pollution control grants to... the Clean Water Act. (b) Purpose of program. Water pollution control grants are awarded to...

  18. 40 CFR 35.160 - Purpose.

    Code of Federal Regulations, 2011 CFR

    2011-07-01

    ... ASSISTANCE Environmental Program Grants Water Pollution Control (section 106) § 35.160 Purpose. (a) Purpose of section. Sections 35.160 through 35.168 govern Water Pollution Control Grants to State and... Clean Water Act. (b) Purpose of program. Water Pollution Control Grants are awarded to assist...

  19. 40 CFR 35.580 - Purpose.

    Code of Federal Regulations, 2012 CFR

    2012-07-01

    ... ASSISTANCE Environmental Program Grants for Tribes Water Pollution Control (sections 106 and 518) § 35.580 Purpose. (a) Purpose of section. Sections 35.580 through 35.588 govern water pollution control grants to... the Clean Water Act. (b) Purpose of program. Water pollution control grants are awarded to...

  20. Doped semiconductor nanocrystal based fluorescent cellular imaging probes

    NASA Astrophysics Data System (ADS)

    Maity, Amit Ranjan; Palmal, Sharbari; Basiruddin, Sk; Karan, Niladri Sekhar; Sarkar, Suresh; Pradhan, Narayan; Jana, Nikhil R.

    2013-05-01

    functionalisation of doped nanocrystals, property of functionalized nanocrystals, quantification of cell labeling and control labeling experiments. See DOI: 10.1039/c3nr00549f

  1. Strategies on the Design of Nitrogen-Doped Graphene.

    PubMed

    Wang, Haibo; Xie, Mingshi; Thia, Larissa; Fisher, Adrian; Wang, Xin

    2014-01-01

    Substitutional nitrogen doping in graphene has been a very powerful tool to tailor the pristine property of graphene and furthermore extend its application. While nitrogen-doped graphene (N-graphene) has shown many potential applications in catalysis, electronics, sensors and so on, there is still a lack of accurate control of substitutional nitrogen doping, and higher performance toward various applications is always needed. This Perspective summarizes the ongoing developments toward better control of nitrogen doping. Moreover, two recent strategies aiming to promote the activity of N-graphene are also discussed.

  2. Three-Dimensional Network of N-Doped Carbon Ultrathin Nanosheets with Closely Packed Mesopores: Controllable Synthesis and Application in Electrochemical Energy Storage.

    PubMed

    Zhu, Shan; Li, Jiajun; Ma, Liying; Guo, Lichao; Li, Qunying; He, Chunnian; Liu, Enzuo; He, Fang; Shi, Chunsheng; Zhao, Naiqin

    2016-05-11

    A flexible one-pot strategy for fabricating a 3D network of nitrogen-doped (N-doped) carbon ultrathin nanosheets with closely packed mesopores (N-MCN) via an in situ template method is reported in this research. The self-assembly soluble salts (NaCl and Na2SiO3) serve as hierarchical templates and support the formation of a 3D glucose-urea complex. The organic complex is heat-treated to obtain a 3D N-doped carbon network constructed by mesoporous nanosheets. Especially, both the mesoporous structure and doping content can be easily tuned by adjusting the ratio of raw materials. The large specific surface area and closely packed mesopores facilitate the lithium ion intercalation/deintercalation accordingly. Besides, the nitrogen content improves the lithium storage ability and capacitive properties. Due to the synergistic effect of hierarchical structure and heteroatom composition, the 3D N-MCN shows excellent characteristics as the electrode of a lithium ion battery and supercapacitor, such as ultrahigh reversible storage capacity (1222 mAh g(-1) at 0.1 A g(-1)), stable long cycle performance at high current density (600 cycles at 2 A g(-1)), and high capacitive properties (225 F g(-1) at 1 A g(-1) and 163 F g(-1) at 50 A g(-1)). PMID:27093444

  3. Controlled direct growth of Al2O3-doped HfO2 films on graphene by H2O-based atomic layer deposition.

    PubMed

    Zheng, Li; Cheng, Xinhong; Yu, Yuehui; Xie, Yahong; Li, Xiaolong; Wang, Zhongjian

    2015-02-01

    Graphene has been drawing worldwide attention since its discovery in 2004. In order to realize graphene-based devices, thin, uniform-coverage and pinhole-free dielectric films with high permittivity on top of graphene are required. Here we report the direct growth of Al2O3-doped HfO2 films onto graphene by H2O-based atom layer deposition (ALD). Al2O3-onto-HfO2 stacks benefited the doping of Al2O3 into HfO2 matrices more than HfO2-onto-Al2O3 stacks did due to the micro-molecular property of Al2O3 and the high chemical activity of trimethylaluminum (TMA). Al2O3 acted as a network modifier, maintained the amorphous structure of the film even to 800 °C, and made the film smooth with a root mean square (RMS) roughness of 0.8 nm, comparable to the surface of pristine graphene. The capacitance and the relative permittivity of Al2O3-onto-HfO2 stacks were up to 1.18 μF cm(-2) and 12, respectively, indicating the high quality of Al2O3-doped HfO2 films on graphene. Moreover, the growth process of Al2O3-doped HfO2 films introduced no detective defects into graphene confirmed by Raman measurements. PMID:25519447

  4. Controllable growth of vertically aligned Bi-doped TiO2 nanorod arrays for all-oxide solid-state DSSCs

    NASA Astrophysics Data System (ADS)

    Asemi, Morteza; Ghanaatshoar, Majid

    2016-09-01

    In this study, vertically aligned Bi-doped TiO2 nanorod arrays as photoanodes were successfully grown on the fluorine-doped tin oxide by hydrothermal method. Structural analysis showed that bismuth was successfully incorporated into the TiO2 lattice at low concentration, but at higher concentration, phase segregation of Bi2O3 in the TiO2 matrix was occurred. TiO2 nanorods with 3 % bismuth concentration had minimum electrical resistivity. As the solid-state electrolyte, Mg-doped CuCrO2 nanoparticles with p-type conductivity were synthesized by sol-gel method. The fabricated all-oxide solid-state dye-sensitized solar cells with Bi-doped TiO2 nanorods displayed better photovoltaic performance due to the presence of Bi. The improved cell performance was correlated with the higher dye loading, slower charge recombination rate and the higher electrical conductivity of the photoanodes. After mechanical pressing, the all-oxide solid-state DSSC exhibited enhanced photovoltaic performance due to the formation of the large neck between adjacent nanoparticles by mechanical sintering. The open-circuit photovoltage decay measurement of the devices and electrical conductivity of the nanoparticles before and after pressing revealed that the mechanical pressing technique reduces charge recombination rate and facilitates electron transport through the interconnected nanoparticles.

  5. Preparation of well-dispersed Mg-doped LaCoO3 nanocrystals with controllable particle size and high visible-light photocatalytic activity.

    PubMed

    Sun, Shangmei; Pang, Guangsheng; Huang, Yuliang; Li, Chunguang; Feng, Shouhua

    2010-08-01

    Mg-doped LaCoO3 nanocrystals are prepared by a modified sol-gel method. Excess MgO is used to inhibit the crystal growth and agglomeration during the calcination process. A series of Mg-doped LaCoO3 nanocrystals with average crystallite size varying from 13.4 to 31.6 nm can be obtained by changing the molar ratio of Mg:La from 4:1 to 1:10 in the reaction mixture. The largest BET surface area observed is 64.5 m2/g if the molar ratio of Mg:La is 4:1. The product can be well dispersed in water and a very stable colloid formed without any stabilizer. The photocatalytic performance of Mg-doped LaCoO3 nanocrystals is evaluated by the degradation of Reactive Brilliant Red X-3B solution. The well-dispersed Mg-doped LaCoO3 nanocrystals exhibit high visible-light photocatalytic activity.

  6. Numerical Studies of Doped Iron Pnictides

    NASA Astrophysics Data System (ADS)

    Bishop, Christopher; Liang, Shuhua; Moreo, Adriana; Dagotto, Elbio

    The phase diagram of electron-doped pnictides is studied varying the temperature, electronic density, and isotropic disorder strength and dilution via numerical studies of a three-orbital spin-fermion model with lattice degrees of freedom. Doping introduces disorder but in theoretical studies the effect of the randomly located dopants is difficult to address. Numerically the effects of electronic doping, regulated by a chemical potential, and impurity disorder at randomly selected sites can be independently controlled. It was found that the reduction with doping of the Neel and the structural transition temperatures, and the stabilization of a nematic state, is mainly controlled by the magnetic dilution due to the disorder. Fermi surface changes due to doping affect only slightly both critical temperatures. Our findings are compatible with neutron scattering and STM results, unveiling a patchy network of locally magnetically ordered anisotropic clusters, despite the isotropic disorder. The fragile tendency to nematicity intrinsic of translational invariant electronic systems needs to be supplemented by disorder and dilution to stabilize the robust nematic phase experimentally found in electron-doped 122 pnictides. National Science Foundation Grant No. DMR-1404375.

  7. Performance analysis of a concatenated erbium-doped fiber amplifier supporting four mode groups

    NASA Astrophysics Data System (ADS)

    Qin, Zujun; Fan, Di; Zhang, Wentao; Xiong, Xianming

    2016-05-01

    An erbium-doped fiber amplifier (EDFA) supporting four mode groups has been theoretically designed by concatenating two sections of erbium-doped fibers (EDFs). Each EDF has a simple erbium doping profile for the purpose of reducing its fabrication complexity. We propose a modified genetic algorithm (GA) to provide detailed investigations on the concatenated amplifier. Both the optimal fiber length and erbium doping radius in each EDF have been found to minimize the gain difference between signal modes. Results show that the parameters of the central-doped EDF have a greater impact on the amplifier performance compared to those of the annular-doped one. We then investigate the influence of the small deviations of the erbium fiber length, doping radius and doping concentration of each EDF from their optimal values upon the amplifier performance, and discuss their design tolerances in obtaining a desirable amplification characteristics.

  8. A p → n transition for Sn-doped Cu(In,Ga)Se{sub 2} bulk materials

    SciTech Connect

    Monsefi, Mehrdad; Kuo, Dong-Hau

    2013-08-15

    Cu(In,Ga)Se{sub 2} (CIGSe) pellets at different Sn contents were fabricated by reactive liquid-phase sintering at 600–700 °C with the help of sintering aids of Sb{sub 2}S{sub 3} and Te. Powder preparation was based upon the molecular formula of Cu{sub 0.9}[(In{sub 0.7−x}Sn{sub x}Ga{sub 0.3}){sub 0.9}Sb{sub 0.1}](S{sub 0.15}Te{sub 0.2}Se{sub 1.65}) or Sn-x-CIGSe. Morphology, structure, and electrical property of Sn-doped CIGSe bulks were investigated. The composition of Sn-doped CIGSe is purposely designed for studying the doping effect on the CIGSe performance. The unexpected increase in hole concentration of CIGSe due to the donor doping is rationalized. A controllable n-type semiconductor is deliberately achieved for Sn-0.15-CIGSe and important for making a p/n homojunction in CIGSe solar cells. - Graphical abstract: The controls in defect type and electrical properties of Cu(In,Ga)Se{sub 2} by doping Sn{sup 4+} on the In{sup 3+} site. Highlights: • n-type Sn-CIGSe with n{sub e} of 6.4×10{sup 16} cm{sup −3} and μ{sub e} of 2.3 cm{sup 2}/V s was obtained. • This n-type Sn-CIGSe was obtained by material design and composition control. • The reported n-type CIGSe was obtained from the Zn/CIGSe and CdS/CIGSe bilayers. • Extrinsic donor doping was explored through the results of electrical properties. • A n/p homojunction with Sn-CIGSe and undoped one can be used for solar cell devices.

  9. Porous Allograft Bone Scaffolds: Doping with Strontium

    PubMed Central

    Zhao, Yantao; Guo, Dagang; Hou, Shuxun; Zhong, Hongbin; Yan, Jun; Zhang, Chunli; Zhou, Ying

    2013-01-01

    Strontium (Sr) can promote the process of bone formation. To improve bioactivity, porous allograft bone scaffolds (ABS) were doped with Sr and the mechanical strength and bioactivity of the scaffolds were evaluated. Sr-doped ABS were prepared using the ion exchange method. The density and distribution of Sr in bone scaffolds were investigated by inductively coupled plasma optical emission spectrometry (ICP-OES), X-ray photoelectron spectroscopy (XPS), and energy-dispersive X-ray spectroscopy (EDS). Controlled release of strontium ions was measured and mechanical strength was evaluated by a compressive strength test. The bioactivity of Sr-doped ABS was investigated by a simulated body fluid (SBF) assay, cytotoxicity testing, and an in vivo implantation experiment. The Sr molar concentration [Sr/(Sr+Ca)] in ABS surpassed 5% and Sr was distributed nearly evenly. XPS analyses suggest that Sr combined with oxygen and carbonate radicals. Released Sr ions were detected in the immersion solution at higher concentration than calcium ions until day 30. The compressive strength of the Sr-doped ABS did not change significantly. The bioactivity of Sr-doped material, as measured by the in vitro SBF immersion method, was superior to that of the Sr-free freeze-dried bone and the Sr-doped material did not show cytotoxicity compared with Sr-free culture medium. The rate of bone mineral deposition for Sr-doped ABS was faster than that of the control at 4 weeks (3.28±0.23 µm/day vs. 2.60±0.20 µm/day; p<0.05). Sr can be evenly doped into porous ABS at relevant concentrations to create highly active bone substitutes. PMID:23922703

  10. Porous allograft bone scaffolds: doping with strontium.

    PubMed

    Zhao, Yantao; Guo, Dagang; Hou, Shuxun; Zhong, Hongbin; Yan, Jun; Zhang, Chunli; Zhou, Ying

    2013-01-01

    Strontium (Sr) can promote the process of bone formation. To improve bioactivity, porous allograft bone scaffolds (ABS) were doped with Sr and the mechanical strength and bioactivity of the scaffolds were evaluated. Sr-doped ABS were prepared using the ion exchange method. The density and distribution of Sr in bone scaffolds were investigated by inductively coupled plasma optical emission spectrometry (ICP-OES), X-ray photoelectron spectroscopy (XPS), and energy-dispersive X-ray spectroscopy (EDS). Controlled release of strontium ions was measured and mechanical strength was evaluated by a compressive strength test. The bioactivity of Sr-doped ABS was investigated by a simulated body fluid (SBF) assay, cytotoxicity testing, and an in vivo implantation experiment. The Sr molar concentration [Sr/(Sr+Ca)] in ABS surpassed 5% and Sr was distributed nearly evenly. XPS analyses suggest that Sr combined with oxygen and carbonate radicals. Released Sr ions were detected in the immersion solution at higher concentration than calcium ions until day 30. The compressive strength of the Sr-doped ABS did not change significantly. The bioactivity of Sr-doped material, as measured by the in vitro SBF immersion method, was superior to that of the Sr-free freeze-dried bone and the Sr-doped material did not show cytotoxicity compared with Sr-free culture medium. The rate of bone mineral deposition for Sr-doped ABS was faster than that of the control at 4 weeks (3.28 ± 0.23 µm/day vs. 2.60 ± 0.20 µm/day; p<0.05). Sr can be evenly doped into porous ABS at relevant concentrations to create highly active bone substitutes. PMID:23922703

  11. Polarization induced doped transistor

    DOEpatents

    Xing, Huili; Jena, Debdeep; Nomoto, Kazuki; Song, Bo; Zhu, Mingda; Hu, Zongyang

    2016-06-07

    A nitride-based field effect transistor (FET) comprises a compositionally graded and polarization induced doped p-layer underlying at least one gate contact and a compositionally graded and doped n-channel underlying a source contact. The n-channel is converted from the p-layer to the n-channel by ion implantation, a buffer underlies the doped p-layer and the n-channel, and a drain underlies the buffer.

  12. Electrical doping of organic molecular semiconductors

    NASA Astrophysics Data System (ADS)

    Gao, Weiying

    2004-11-01

    Electrical doping is perceived as a key to enhance the performance and versatility of organic molecular devices. Understanding the doping mechanism and the impact of doping on interface electronic structures is very important for better control of the doping. We show that an efficient p-doping is a result of a good energy match between the host ionization energy and the dopant electron affinity, via a study of the electronic structure of host and dopant materials using direct and inverse photoemission spectroscopies (UPS/IPES). The hole transport materials zinc phthalocyanine (ZnPc) and N,N'-diphenyl-N,N '-bis(1-naphthyl)-1,1'-biphenyl-4,4 '-diamine (alpha-NPD) are used as the host materials, and the strong acceptor material tetrafluorotetracyanoquinodimethane (F4 -TCNQ) is the p-type dopant. In p-doped films, EF moves closer to the HOMO, analogous to inorganic semiconductors. The ultimate position of EF with respect to the HOMO in highly doped film is limited by the large polarization and relaxation in molecular solids, especially in 3-D molecules like alpha-NPD. The study of the impact of doping at metal-organic interfaces shows that the interface electronic structure, i.e. interface dipole, ionization energy and EF-HOMO, is nearly independent of doping, although the bulk EF-HOMO of the doped film is determined by the dopant concentration. A depletion region is formed at the interface with its width depending on the dopant concentration similarly as metal-inorganic semiconductor interfaces. This narrow space charge region greatly improves hole injection by several orders of magnitude via tunneling. The impact of doping on the energy alignment at organic-organic heterojunction interfaces is found to be different compared to MO interfaces. Interface dipoles are generally seen upon doping of one organic material at these weakly interacting OO interfaces, and the electron and hole barriers at the interface are correspondingly modified. The interface dipole is found

  13. Detecting doping use: more than an analytical problem.

    PubMed

    Delanghe, J R; Maenhout, T M; Speeckaert, M M; De Buyzere, M L

    2014-01-01

    The recent Armstrong case, where more than 250 negative doping tests are confronted with the athlete's confession of erythropoietin use, blood doping, steroid, and growth hormone abuse, illustrates the limitations of current laboratory tests in detecting doping in sport. Despite numerous doping controls and simultaneous indications of common doping abuse among professional athletes in the last two decades, the number of positive urine tests for recombinant human erythropoietin (rHuEPO) remains remarkably low. Athletes are using various masking strategies, among them protease inhibitors, intravenous injections of rHuEPO and alternative erythropoiesis stimulating agents. As one of the countermeasures, the Athlete's Biological Passport has been introduced. The sensitivity of the Athlete's Biological Passport is limited if the effect of a low-dose doping remains within the intra-individual reference range. A possible solution could be the use of a novel Epo test (MAIIA Diagnostics). Another performance-enhancing strategy is the return to 'old' doping techniques, such as autologous blood transfusions. Several indirect methods to detect autologous blood transfusions have been proposed with the majority relying on changes in erythropoiesis-sensitive blood markers. Currently, an algorithm based on the haemoglobin (Hb) level concentration and the percentage of reticulocytes (OFF-hr model; Hb(g/l)-60·√%ret) is approved by the World Anti-Doping Agency. Genetic factors have been identified which may interfere with test interpretation. A large inter- and intra-ethnic variation in testosterone glucuronidation and excretion has been described. Consideration of genetic variation should improve performance of the testosterone doping test. Taking into account the pre-analytical care and better tailoring of the threshold values could increase test sensitivity. Anti-doping laboratories should routinely adjust for multiple testing as failure of doping control to detect cheaters

  14. Reversible tuning of the collapsed tetragonal phase transition in CaF e2A s2 by separate control of chemical pressure and electron doping

    NASA Astrophysics Data System (ADS)

    Zhao, K.; Stingl, C.; Manna, R. S.; Jin, C. Q.; Gegenwart, P.

    2015-12-01

    Single crystals of Ca (Fe1-xR ux ) 2A s2(0 ≤x ≤0.065 ) and C a1 -yL ay(Fe0.973Ru0.027 ) 2A s2(0 ≤y ≤0.2 ) have been synthesized and studied with respect to their structural, electronic, and magnetic properties. The partial substitution of Fe by Ru induces a decrease of the c -axis constant leading for x ≤0.023 to a suppression of the coupled magnetic and structural (tetragonal to orthorhombic) transitions. At xcr=0.023 a first-order transition to a collapsed tetragonal (CT) phase is found, which behaves like a Fermi liquid and which is stabilized by further increase of x . The absence of superconductivity near xcr is consistent with truly hydrostatic pressure experiments on undoped CaF e2A s2 . Starting in the CT regime at x =0.027 , we investigate the additional effect of electron doping by partial replacement of Ca by La. Most remarkably, with increasing y the CT phase transition is destabilized and the system is tuned back into a tetragonal ground state at y ≥ 0.08. This effect is ascribed to a weakening of interlayer As-As bonds by electron doping. Upon further electron doping filamentary superconductivity with Tc of 41 K at y =0.2 is observed.

  15. Boron-doped superlattices and Bragg mirrors in diamond

    SciTech Connect

    Fiori, A.; Bousquet, J.; Eon, D.; Omnès, F.; Bustarret, E.; Bellet-Amalric, E.

    2014-08-25

    A periodic modulation of the boron doping level of single crystal diamond multilayers over more than three orders of magnitude during epitaxial growth by microwave plasma-enhanced chemical vapor deposition is shown to yield Bragg mirrors in the visible. The thicknesses and doping level of the individual layers were controlled by in situ spectroscopic ellipsometry, enabling to tune the reflectance peak to the wavelength range of diamond color centers, such as NV{sup 0} or NV{sup −}. The crystalline quality, periodicity, and sharpness of the doping transitions in these doping superlattices over tens of periods were confirmed by high resolution X-ray diffraction.

  16. Structural evolution and defect control of yttrium-doped ZrO2 films grown by a sol-gel method

    NASA Astrophysics Data System (ADS)

    Jeong, Kwang Sik; Song, Jinho; Lim, Donghyeok; Lee, Myung Soo; Kim, Hyoungsub; Cho, Mann-Ho

    2014-11-01

    Yttrium-doped ZrO2 thin-films were prepared on Si substrates via sol-gel synthesis at a low temperature of 700 °C. During sol-gel synthesis, yttrium can easily take the place of the zirconium in ZrO2, even at low ambient process temperatures. We were therefore able to successfully synthesize yttrium-doped zirconium oxide (Y-ZrO2) with a clean interface without the generation of zirconium silicate, which is formed at high temperatures (∼1000 °C). Doped yttrium can eliminate the interstitial oxygen contained in ZrO2 thin films as O2-1 states. The conduction band offset (CBO) is also increased via yttrium doping: from 1.69 eV for ZrO2 to 1.99 eV for Y-ZrO2 in the as-grown films, and from 1.27 eV for ZrO2 to 1.35 eV for Y-ZrO2 in the annealed films. The difference observed in the CBO of the as-grown films may be caused by interstitial oxygen, which is formed in the ZrO2 films, while the annealed films have oxygen vacancies. The reported data show that yttrium doping of ZrO2 induces the formation of a yttrium-oxygen vacancy pair, which can reduce the formation energy of oxygen vacancies. However, using the density-of-states analysis from the VASP code density functional theory (DFT) calculations, we confirm that the oxygen vacancy in the Y-ZrO2 did not generate defect states within the silicon band gap, whereas in the ZrO2 it did generate defect states within the silicon band gap. Using the conductance method, reductions in the interfacial trap charge densities of approximately 20% were observed near the mid-gap in Y-ZrO2, as compared with undoped ZrO2. Following the application of electrical stress, the reduction in interface states was found to be greater in the Y-ZrO2 film, which is consistent with the DFT calculation.

  17. Plasma process optimization for N-type doping applications

    NASA Astrophysics Data System (ADS)

    Raj, Deven; Persing, Harold; Salimian, Siamak; Lacey, Kerry; Qin, Shu; Hu, Jeff Y.; McTeer, Allen

    2012-11-01

    Plasma doping (PLAD) has been adopted across the implant technology space and into high volume production for both conventional DRAM and NAND doping applications. PLAD has established itself as an alternative to traditional ion implantation by beamline implantation. The push for high doping concentration, shallow doping depth, and conformal doping capability expand the need for a PLAD solution to meet such requirements. The unique doping profile and doping characteristics at high dose rates allow for PLAD to deliver a high throughput, differentiated solution to meet the demand of evolving transistor technology. In the PLAD process, ions are accelerated to the wafer as with a negative wafer bias applied to the wafer. Competing mechanisms, such as deposition, sputtering, and etching inherent in plasma doping require unique control and process optimization. In this work, we look at the distinctive process tool control and characterization features which enable an optimized doping process using n-type (PH3 or AsH3) chemistries. The data in this paper will draw the relationship between process optimization through plasma chemistry study to the wafer level result.

  18. Plasma process optimization for N-type doping applications

    SciTech Connect

    Raj, Deven; Persing, Harold; Salimian, Siamak; Lacey, Kerry; Qin Shu; Hu, Jeff Y.; McTeer, Allen

    2012-11-06

    Plasma doping (PLAD) has been adopted across the implant technology space and into high volume production for both conventional DRAM and NAND doping applications. PLAD has established itself as an alternative to traditional ion implantation by beamline implantation. The push for high doping concentration, shallow doping depth, and conformal doping capability expand the need for a PLAD solution to meet such requirements. The unique doping profile and doping characteristics at high dose rates allow for PLAD to deliver a high throughput, differentiated solution to meet the demand of evolving transistor technology. In the PLAD process, ions are accelerated to the wafer as with a negative wafer bias applied to the wafer. Competing mechanisms, such as deposition, sputtering, and etching inherent in plasma doping require unique control and process optimization. In this work, we look at the distinctive process tool control and characterization features which enable an optimized doping process using n-type (PH{sub 3} or AsH{sub 3}) chemistries. The data in this paper will draw the relationship between process optimization through plasma chemistry study to the wafer level result.

  19. Multiple delta doping of single crystal cubic boron nitride films heteroepitaxially grown on (001)diamonds

    SciTech Connect

    Yin, H.; Ziemann, P.

    2014-06-23

    Phase pure cubic boron nitride (c-BN) films have been epitaxially grown on (001) diamond substrates at 900 °C. The n-type doping of c-BN epitaxial films relies on the sequential growth of nominally undoped (p-) and Si doped (n-) layers with well-controlled thickness (down to several nanometer range) in the concept of multiple delta doping. The existence of nominally undoped c-BN overgrowth separates the Si doped layers, preventing Si dopant segregation that was observed for continuously doped epitaxial c-BN films. This strategy allows doping of c-BN films can be scaled up to multiple numbers of doped layers through atomic level control of the interface in the future electronic devices. Enhanced electronic transport properties with higher hall mobility (10{sup 2} cm{sup 2}/V s) have been demonstrated at room temperature as compared to the normally continuously Si doped c-BN films.

  20. Response to 'Comment on 'Controllable local modification of fractured Nb-doped SrTiO{sub 3} surfaces' [Appl. Phys. Lett. 98, 256102 (2011)'.

    SciTech Connect

    Chien, T. Y.; Santos, T. S.; Bode, M.; Guisinger, N. P.; Freeland, J. W.

    2011-06-20

    In their comment, Chen et al. try to argue that the experimentally observed controllable voltage-induced surface modification, which was attributed to a local electric field-induced atom transfer from the surface to the tip, is rather caused by either an oxidation process and/or a resistance change. In this response, we will show that we can rule out these two effects in our experiment. The statements by Chen et al. are based on two arguments: (1) the tip modification after transferring an adatom should alter the dI/dV contrast, which was not seen in our experiments and (2) the vacuum conditions in our experiment are similar to earlier reports on resistance switching. First, Chen et al. discuss that the adsorption on the tip should alter the topographic contrast, as many papers have reported. In fact, in our experiments we frequently observed tip modifications at high bias voltage. These typically result in slight changes in scanning tunneling spectroscopy data [see, for example, the spectra in Fig. 3(b) in Ref. 4 and Fig. 2(d) of Ref. 5] but only weakly affected the topographic contrast. Second, Chen et al. claim that oxidation is another possible mechanism to explain our experimental observations. To support this claim, they compare our results to an earlier publication showing resistance switching. In fact, the resistance switching mechanism is related to oxygen vacancy migration or local surface oxidation. The mechanism of oxygen vacancy migration requires a 'forming' process with a threshold current in the order of microampere or even milliampere. In our experimental setup, however, we used tunneling currents in the order of 50 pA. Even during surface modification, which was performed at open feedback loop conditions with voltage pulse of up to 3 or -5 V, the maximum transient current did not exceed a few nanoampere. Therefore, we can safely exclude oxygen vacancy migration as a potential mechanism for the observed surface modification. As a second potential

  1. Chrome doped gallium arsenide evaluation

    SciTech Connect

    Pocha, M.D.; Morse, J.D.; Brazes, W.F.

    1987-10-10

    We received, for free, two sets of Chrome doped Gallium Arsenide (GaAs:Cr) wafers, one from Cominco Electronic Materials, Inc., and the other from Furakawa Electric Co., for the purpose of evaluation as potential material for high speed photoconductive detectors. In return for the free material we promised to give the two manufacturers feed back on our evaluation of these wafers. The primary purpose of this report is to present the results of our evaluation of these wafers and conclusions regarding the usefulness of heavily doped GaAs:Cr for photoconductive detectors. We have found that response times of less than 100 ps (FWHM) are possible with GaAs:Cr detectors, but that there are several time constants to the decay which result in very long ''tails'' to the impulse response of these detectors. These long tails are unacceptable for most detector applications, but there may be some special cases where GaAs:Cr could be used. 5 figs., 1 tab.

  2. Aero dopes and varnishes

    NASA Technical Reports Server (NTRS)

    Britton, H T S

    1927-01-01

    Before proceeding to discuss the preparation of dope solutions, it will be necessary to consider some of the essential properties which should be possessed of a dope film, deposited in and on the surface of an aero fabric. The first is that it should tighten the material and second it should withstand weathering.

  3. [Doping and sports].

    PubMed

    Lippi, G; Guidi, G

    1999-09-01

    Doping is widely known as the use of banned substances and practices by athletes in an attempt to improve sporting performances. The term doping likely derives from "dope", an ancient expression referred to a primitive alcoholic drink that was used as a stimulant in South African ceremonial dances; gradually, the term was extended and finally adopted his current significance. There are at least two essential reasons to support the fight against doping: the potential harmful effects on athletes and the depth corruption of the fair competition. An exhaustive list of banned substances and methods has been drawn by the International Olympic Committee and further accepted by other International Sport Authorities and Federations. This list, regularly updated, is basically divided into doping substances (stimulants, narcotic analgesics, anabolic agents, diuretics, peptide and glycoprotein hormones and analogues), doping methods (blood doping, pharmacological, chemical and physical manipulation) and drugs subjected to certain restrictions (alcohol, marijuana, local anesthetics, corticosteroids and beta-blockers). Although there might be some medical conditions, which could legitimate the need of these substances or methods, there is no place for their use in sport. Thus, an athlete's consume of any of these substances or methods will result in disqualification. Aim of the present review is to provide a synthetic description of both the desirable effects and the potentially harmful consequences of the use of some of the major doping substances and methods.

  4. Cat-doping: Novel method for phosphorus and boron shallow doping in crystalline silicon at 80 °C

    SciTech Connect

    Matsumura, Hideki; Hayakawa, Taro; Ohta, Tatsunori; Nakashima, Yuki; Miyamoto, Motoharu; Thi, Trinh Cham; Koyama, Koichi; Ohdaira, Keisuke

    2014-09-21

    Phosphorus (P) or boron (B) atoms can be doped at temperatures as low as 80 to 350 °C, when crystalline silicon (c-Si) is exposed only for a few minutes to species generated by catalytic cracking reaction of phosphine (PH₃) or diborane (B₂H₆) with heated tungsten (W) catalyzer. This paper is to investigate systematically this novel doping method, “Cat-doping”, in detail. The electrical properties of P or B doped layers are studied by the Van der Pauw method based on the Hall effects measurement. The profiles of P or B atoms in c-Si are observed by secondary ion mass spectrometry mainly from back side of samples to eliminate knock-on effects. It is confirmed that the surface of p-type c-Si is converted to n-type by P Cat-doping at 80 °C, and similarly, that of n-type c-Si is to p-type by B Cat-doping. The doping depth is as shallow as 5 nm or less and the electrically activated doping concentration is 10¹⁸ to 10¹⁹cm⁻³ for both P and B doping. It is also found that the surface potential of c-Si is controlled by the shallow Cat-doping and that the surface recombination velocity of minority carriers in c-Si can be enormously lowered by this potential control.

  5. 40 CFR 35.140 - Purpose.

    Code of Federal Regulations, 2010 CFR

    2010-07-01

    ... ASSISTANCE Environmental Program Grants Air Pollution Control (section 105) § 35.140 Purpose. (a) Purpose of section. Sections 35.140 through 35.148 govern Air Pollution Control Grants to State, local, interstate, or intermunicipal air pollution control agencies (as defined in section 302(b) of the Clean Air...

  6. Doped graphene supercapacitors

    NASA Astrophysics Data System (ADS)

    Ashok Kumar, Nanjundan; Baek, Jong-Beom

    2015-12-01

    Heteroatom-doped graphitic frameworks have received great attention in energy research, since doping endows graphitic structures with a wide spectrum of properties, especially critical for electrochemical supercapacitors, which tend to complement or compete with the current lithium-ion battery technology/devices. This article reviews the latest developments in the chemical modification/doping strategies of graphene and highlights the versatility of such heteroatom-doped graphitic structures. Their role as supercapacitor electrodes is discussed in detail. This review is specifically focused on the concept of material synthesis, techniques for electrode fabrication and metrics of performance, predominantly covering the last four years. Challenges and insights into the future research and perspectives on the development of novel electrode architectures for electrochemical supercapacitors based on doped graphene are also discussed.

  7. Foam core shield (FCS) systems : a new dual - purpose technology for shielding against meteoroid strike damage and for thermal control of spacecrafts/satellite components

    NASA Technical Reports Server (NTRS)

    Adams, Marc A.; Zwissler, James G.; Hayes, Charles; Fabensky, Beth; Cornelison, Charles; Alexander, Lesley; Bishop, Karen

    2005-01-01

    A new technology is being developed that can protect spacecraft and satellite components against damage from meteoroid strikes and control the thermal environment of the protected components. This technology, called Foam Core Shield (FCS) systems, has the potential to replace the multi-layer insulation blankets (MLI) that have been used on spacecraft for decades. In order to be an attractive candidate for replacing MLI, FCS systems should not only provide superior protection against meteoroid strikes but also provide an equal or superior ability to control the temperature of the protected component. Properly designed FCS systems can provide these principal functions, meteoroid strike protection and thermal control, with lower system mass and a smaller system envelope than ML.

  8. H. R. 3282: To amend the Federal Water Pollution Control Act to provide for the renewal of the quality of the Nation's waters, and for other purposes

    SciTech Connect

    Not Available

    1983-01-01

    H.R. 3282, also called the Water Quality Renewal Act of 1984, amends the Federal Water Pollution Act in ways that make budget and authorization adjustments, limit construction grants, and modify compliance deadlines by replacing specific deadlines with instructions for as expeditious action as is possible. The Bill also deals with control strategies for toxic pollutants, civil penalties, implementation programs for nonpoint pollution source control, and dates for complying with coal mining pollution requirements. Specific areas dealt with in the legislation include agricultural stormwater discharge into lakes and streams, raw sewage discharges, alternative processing, pretreatment of toxic pollutants, and sulfide corrosion studies in designated areas.

  9. Doping against the native propensity of MoS₂: Degenerate hole doping by cation substitution

    SciTech Connect

    Suh, Joonki; Park, Tae-Eon; Lin, Der-Yuh; Fu, Deyi; Park, Joonsuk; Jung, Hee Joon; Chen, Yabin; Ko, Changhyun; Jang, Chaun; Sun, Yinghui; Sinclair, Robert; Chang, Joonyeon; Tongay, Sefaattin; Wu, Junqiao

    2014-12-10

    Layered transition metal dichalcogenides (TMDs) draw much attention as the key semiconducting material for two-dimensional electrical, optoelectronic, and spintronic devices. For most of these applications, both n- and p-type materials are needed to form junctions and support bipolar carrier conduction. However, typically only one type of doping is stable for a particular TMD. For example, molybdenum disulfide (MoS₂) is natively an n-type presumably due to omnipresent electron-donating sulfur vacancies, and stable/controllable p-type doping has not been achieved. The lack of p-type doping hampers the development of charge-splitting p–n junctions of MoS₂, as well as limits carrier conduction to spin-degenerate conduction bands instead of the more interesting, spin-polarized valence bands. Traditionally, extrinsic p-type doping in TMDs has been approached with surface adsorption or intercalation of electron-accepting molecules. However, practically stable doping requires substitution of host atoms with dopants where the doping is secured by covalent bonding. In this work, we demonstrate stable p-type conduction in MoS₂ by substitutional niobium (Nb) doping, leading to a degenerate hole density of ~3 × 10¹⁹ cm⁻³. Structural and X-ray techniques reveal that the Nb atoms are indeed substitutionally incorporated into MoS₂ by replacing the Mo cations in the host lattice. van der Waals p–n homojunctions based on vertically stacked MoS₂ layers are fabricated, which enable gate-tunable current rectification. A wide range of microelectronic, optoelectronic, and spintronic devices can be envisioned from the demonstrated substitutional bipolar doping of MoS₂. From the miscibility of dopants with the host, it is also expected that the synthesis technique demonstrated here can be generally extended to other TMDs for doping against their native unipolar propensity.

  10. Perspective: Extremely fine tuning of doping enabled by combinatorial molecular-beam epitaxy

    NASA Astrophysics Data System (ADS)

    Wu, J.; Božović, I.

    2015-06-01

    Chemical doping provides an effective method to control the electric properties of complex oxides. However, the state-of-art accuracy in controlling doping is limited to about 1%. This hampers elucidation of the precise doping dependences of physical properties and phenomena of interest, such as quantum phase transitions. Using the combinatorial molecular beam epitaxy, we improve the accuracy in tuning the doping level by two orders of magnitude. We illustrate this novel method by two examples: a systematic investigation of the doping dependence of interface superconductivity, and a study of the competing ground states in the vicinity of the insulator-to-superconductor transition.

  11. Analytical development of a binuclear oxo-manganese complex bio-inspired on oxidase enzyme for doping control analysis of acetazolamide.

    PubMed

    Machini, Wesley B S; Teixeira, Marcos F S

    2016-05-15

    A bio-inspired electrochemical sensor using a binuclear oxo-manganese complex was evaluated and applied in the detection of a substance associated with doping in sports: acetazolamide (ACTZ). Investigation was made of the influence of different experimental variables on the electrocatalytic oxidation of ACTZ by the bio-inspired sensor, such as pH and interfering species. The bio-inspired sensor showed the best response in the range from 5.00×10(-9) to 7.00×10(-8) mol L(-1) ACTZ, with a linear range from 5.00×10(-9) to 2.50×10(-8) mol L(-1) and a detection limit of 4.76×10(-9) mol L(-1). The sensor exhibited characteristics similar to the Michaelis-Menten model of an enzymatic electrode, due to the use of a multinucleated complex of manganese with μ-oxo units, which was able to mimic the properties of enzymes with manganese as a cofactor in their composition, such as Mn-containing oxidase. The determination of ACTZ with the bio-inspired sensor was evaluated using three different synthetic biological fluids (plasma, saliva, and urine), demonstrating its viability for use with real samples. The analysis of ACTZ in real urine samples using the bio-inspired sensor, simulating the method adopted by the World Anti-Doping Agency, which revealed viable, suggesting a new and promising platform to be used in these analysis.

  12. Gate-Tunable Dirac Point of Molecular Doped Graphene.

    PubMed

    Solís-Fernández, Pablo; Okada, Susumu; Sato, Tohru; Tsuji, Masaharu; Ago, Hiroki

    2016-02-23

    Control of the type and density of charge carriers in graphene is essential for its implementation into various practical applications. Here, we demonstrate the gate-tunable doping effect of adsorbed piperidine on graphene. By gradually increasing the amount of adsorbed piperidine, the graphene doping level can be varied from p- to n-type, with the formation of p-n junctions for intermediate coverages. Moreover, the doping effect of the piperidine can be further tuned by the application of large negative back-gate voltages, which increase the doping level of graphene. In addition, the electronic properties of graphene are well preserved due to the noncovalent nature of the interaction between piperidine and graphene. This gate-tunable doping offers an easy, controllable, and nonintrusive method to alter the electronic structure of graphene. PMID:26812353

  13. Epidemiological analysis of doping offences in the professional tennis circuit

    PubMed Central

    2010-01-01

    Introduction Tennis is a professional sport under a strict anti-doping control. However, since the first violation of the code, the positive cases have not been statistically studied. The objective of this study was to analyze doping offences in the international professional tennis circuit. Methods All offences to the Doping Code committed by tennis players during 2003-2009 were collected from the ITF official webpage, registered and analyzed. Results An average of 1905.7 (±174.5) samples was obtained per year. Fifty-two doping offences were reported and the overall incidence of positive doping samples accounted for 0.38% and 7.4 (±4.1) cases/year. Male players showed higher incidence doping offences than females (p = 0.0004). The incidence in wheelchair players was higher than in non-handicapped subjects (p = 0.0001) Banned substance distribution showed: stimulants 32.69%, cannabis 23.07%; anabolic 11.53%, diuretics and masking agents 11.53, β2-agonists 9.61%; corticosteroids 3.84%, others 3.84%. The overall incidence of 'social drugs' (cocaine, cannabis) was 36.53%. All EPO and blood samples were normal, while the incidence of 'out-of-competition' offences was 0.12%. The lower incidence of doping was found in Grand Slams tournaments. Conclusions The incidence of positive doping samples among professional tennis players is quite low supporting the assumption that there is no evidence of systematic doping in Tennis. "Social drugs" misuse constitutes the main problem of doping in tennis. Male and wheelchair tennis players showed higher risk of infringing the doping code than their females and non-handicapped counterparts. Findings of this study should help to determine the direction of the ongoing strategy in the fight against doping in Tennis. PMID:21159201

  14. Gene doping in sports.

    PubMed

    Unal, Mehmet; Ozer Unal, Durisehvar

    2004-01-01

    Gene or cell doping is defined by the World Anti-Doping Agency (WADA) as "the non-therapeutic use of genes, genetic elements and/or cells that have the capacity to enhance athletic performance". New research in genetics and genomics will be used not only to diagnose and treat disease, but also to attempt to enhance human performance. In recent years, gene therapy has shown progress and positive results that have highlighted the potential misuse of this technology and the debate of 'gene doping'. Gene therapies developed for the treatment of diseases such as anaemia (the gene for erythropoietin), muscular dystrophy (the gene for insulin-like growth factor-1) and peripheral vascular diseases (the gene for vascular endothelial growth factor) are potential doping methods. With progress in gene technology, many other genes with this potential will be discovered. For this reason, it is important to develop timely legal regulations and to research the field of gene doping in order to develop methods of detection. To protect the health of athletes and to ensure equal competitive conditions, the International Olympic Committee, WADA and International Sports Federations have accepted performance-enhancing substances and methods as being doping, and have forbidden them. Nevertheless, the desire to win causes athletes to misuse these drugs and methods. This paper reviews the current status of gene doping and candidate performance enhancement genes, and also the use of gene therapy in sports medicine and ethics of genetic enhancement.

  15. To develop a dynamic model of a collector loop for purpose of improved control of solar heating and cooling. Final technical report. [TRNSYS code

    SciTech Connect

    Herczfeld, P R; Fischl, R

    1980-01-01

    The program objectives were to (1) assess the feasibility of using the TRNSYS computer code for solar heating and cooling control studies and modify it wherever possible, and (2) develop a new dynamic model of the solar collector which reflects the performance of the collector under transient conditions. Also, the sensitivity of the performance of this model to the various system parameters such as collector time constants, flow rates, turn-on and turn-off temperature set points, solar insolation, etc., was studied. Results are presented and discussed. (WHK)

  16. The dawn of computer-assisted robotic osteotomy with ytterbium-doped fiber laser.

    PubMed

    Sotsuka, Yohei; Nishimoto, Soh; Tsumano, Tomoko; Kawai, Kenichiro; Ishise, Hisako; Kakibuchi, Masao; Shimokita, Ryo; Yamauchi, Taisuke; Okihara, Shin-ichiro

    2014-05-01

    Currently, laser radiation is used routinely in medical applications. For infrared lasers, bone ablation and the healing process have been reported, but no laser systems are established and applied in clinical bone surgery. Furthermore, industrial laser applications utilize computer and robot assistance; medical laser radiations are still mostly conducted manually nowadays. The purpose of this study was to compare the histological appearance of bone ablation and healing response in rabbit radial bone osteotomy created by surgical saw and ytterbium-doped fiber laser controlled by a computer with use of nitrogen surface cooling spray. An Ytterbium (Yb)-doped fiber laser at a wavelength of 1,070 nm was guided by a computer-aided robotic system, with a spot size of 100 μm at a distance of approximately 80 mm from the surface. The output power of the laser was 60 W at the scanning speed of 20 mm/s scan using continuous wave system with nitrogen spray level 0.5 MPa (energy density, 3.8 × 10(4) W/cm(2)). Rabbits radial bone osteotomy was performed by an Yb-doped fiber laser and a surgical saw. Additionally, histological analyses of the osteotomy site were performed on day 0 and day 21. Yb-doped fiber laser osteotomy revealed a remarkable cutting efficiency. There were little signs of tissue damage to the muscle. Lased specimens have shown no delayed healing compared with the saw osteotomies. Computer-assisted robotic osteotomy with Yb-doped fiber laser was able to perform. In rabbit model, laser-induced osteotomy defects, compared to those by surgical saw, exhibited no delayed healing response. PMID:24241973

  17. The dawn of computer-assisted robotic osteotomy with ytterbium-doped fiber laser.

    PubMed

    Sotsuka, Yohei; Nishimoto, Soh; Tsumano, Tomoko; Kawai, Kenichiro; Ishise, Hisako; Kakibuchi, Masao; Shimokita, Ryo; Yamauchi, Taisuke; Okihara, Shin-ichiro

    2014-05-01

    Currently, laser radiation is used routinely in medical applications. For infrared lasers, bone ablation and the healing process have been reported, but no laser systems are established and applied in clinical bone surgery. Furthermore, industrial laser applications utilize computer and robot assistance; medical laser radiations are still mostly conducted manually nowadays. The purpose of this study was to compare the histological appearance of bone ablation and healing response in rabbit radial bone osteotomy created by surgical saw and ytterbium-doped fiber laser controlled by a computer with use of nitrogen surface cooling spray. An Ytterbium (Yb)-doped fiber laser at a wavelength of 1,070 nm was guided by a computer-aided robotic system, with a spot size of 100 μm at a distance of approximately 80 mm from the surface. The output power of the laser was 60 W at the scanning speed of 20 mm/s scan using continuous wave system with nitrogen spray level 0.5 MPa (energy density, 3.8 × 10(4) W/cm(2)). Rabbits radial bone osteotomy was performed by an Yb-doped fiber laser and a surgical saw. Additionally, histological analyses of the osteotomy site were performed on day 0 and day 21. Yb-doped fiber laser osteotomy revealed a remarkable cutting efficiency. There were little signs of tissue damage to the muscle. Lased specimens have shown no delayed healing compared with the saw osteotomies. Computer-assisted robotic osteotomy with Yb-doped fiber laser was able to perform. In rabbit model, laser-induced osteotomy defects, compared to those by surgical saw, exhibited no delayed healing response.

  18. 40 CFR 35.290 - Purpose.

    Code of Federal Regulations, 2014 CFR

    2014-07-01

    ... ASSISTANCE Environmental Program Grants State Indoor Radon Grants (section 306) § 35.290 Purpose. (a) Purpose of section. Sections 35.290 through 35.298 govern Indoor Radon Grants to States (as defined in...) under section 306 of the Toxic Substances Control Act. (b) Purpose of program. (1) State Indoor...

  19. 40 CFR 35.700 - Purpose.

    Code of Federal Regulations, 2012 CFR

    2012-07-01

    ... ASSISTANCE Environmental Program Grants for Tribes Indoor Radon Grants (section 306) § 35.700 Purpose. (a) Purpose of section. Sections 35.700 through 35.708 govern Indoor Radon Grants to Tribes and Intertribal Consortia under section 306 of the Toxic Substances Control Act. (b) Purpose of program. (1) Indoor...

  20. 40 CFR 35.700 - Purpose.

    Code of Federal Regulations, 2014 CFR

    2014-07-01

    ... ASSISTANCE Environmental Program Grants for Tribes Indoor Radon Grants (section 306) § 35.700 Purpose. (a) Purpose of section. Sections 35.700 through 35.708 govern Indoor Radon Grants to Tribes and Intertribal Consortia under section 306 of the Toxic Substances Control Act. (b) Purpose of program. (1) Indoor...

  1. 40 CFR 35.290 - Purpose.

    Code of Federal Regulations, 2012 CFR

    2012-07-01

    ... ASSISTANCE Environmental Program Grants State Indoor Radon Grants (section 306) § 35.290 Purpose. (a) Purpose of section. Sections 35.290 through 35.298 govern Indoor Radon Grants to States (as defined in...) under section 306 of the Toxic Substances Control Act. (b) Purpose of program. (1) State Indoor...

  2. 21 CFR 1401.1 - Purpose.

    Code of Federal Regulations, 2013 CFR

    2013-04-01

    ... 21 Food and Drugs 9 2013-04-01 2013-04-01 false Purpose. 1401.1 Section 1401.1 Food and Drugs OFFICE OF NATIONAL DRUG CONTROL POLICY PUBLIC AVAILABILITY OF INFORMATION § 1401.1 Purpose. The purpose... Act (FOIA), as amended, 5 U.S.C. 552....

  3. 21 CFR 1401.1 - Purpose.

    Code of Federal Regulations, 2011 CFR

    2011-04-01

    ... 21 Food and Drugs 9 2011-04-01 2011-04-01 false Purpose. 1401.1 Section 1401.1 Food and Drugs OFFICE OF NATIONAL DRUG CONTROL POLICY PUBLIC AVAILABILITY OF INFORMATION § 1401.1 Purpose. The purpose... Act (FOIA), as amended, 5 U.S.C. 552....

  4. 21 CFR 1401.1 - Purpose.

    Code of Federal Regulations, 2012 CFR

    2012-04-01

    ... 21 Food and Drugs 9 2012-04-01 2012-04-01 false Purpose. 1401.1 Section 1401.1 Food and Drugs OFFICE OF NATIONAL DRUG CONTROL POLICY PUBLIC AVAILABILITY OF INFORMATION § 1401.1 Purpose. The purpose... Act (FOIA), as amended, 5 U.S.C. 552....

  5. 21 CFR 1401.1 - Purpose.

    Code of Federal Regulations, 2014 CFR

    2014-04-01

    ... 21 Food and Drugs 9 2014-04-01 2014-04-01 false Purpose. 1401.1 Section 1401.1 Food and Drugs OFFICE OF NATIONAL DRUG CONTROL POLICY PUBLIC AVAILABILITY OF INFORMATION § 1401.1 Purpose. The purpose... Act (FOIA), as amended, 5 U.S.C. 552....

  6. 21 CFR 1401.1 - Purpose.

    Code of Federal Regulations, 2010 CFR

    2010-04-01

    ... 21 Food and Drugs 9 2010-04-01 2010-04-01 false Purpose. 1401.1 Section 1401.1 Food and Drugs OFFICE OF NATIONAL DRUG CONTROL POLICY PUBLIC AVAILABILITY OF INFORMATION § 1401.1 Purpose. The purpose of this part is to prescribe rules, guidelines and procedures to implement the Freedom of...

  7. Isoelectronic co-doping

    DOEpatents

    Mascarenhas, Angelo

    2004-11-09

    Isoelectronic co-doping of semiconductor compounds and alloys with deep acceptors and deep donors is used to decrease bandgap, to increase concentration of the dopant constituents in the resulting alloys, and to increase carrier mobilities lifetimes. Group III-V compounds and alloys, such as GaAs and GaP, are isoelectronically co-doped with, for example, N and Bi, to customize solar cells, thermal voltaic cells, light emitting diodes, photodetectors, and lasers on GaP, InP, GaAs, Ge, and Si substrates. Isoelectronically co-doped Group II-VI compounds and alloys are also included.

  8. Phase transitions and doping in semiconductor nanocrystals

    NASA Astrophysics Data System (ADS)

    Sahu, Ayaskanta

    impurities (or doping) allows further control over the electrical and optical properties of nanocrystals. However, while impurity doping in bulk semiconductors is now routine, doping of nanocrystals remains challenging. In particular, evidence for electronic doping, in which additional electrical carriers are introduced into the nanocrystals, has been very limited. Here, we adopt a new approach to electronic doping of nanocrystals. We utilize a partial cation exchange to introduce silver impurities into cadmium selenide (CdSe) and lead selenide (PbSe) nanocrystals. Results indicate that the silver-doped CdSe nanocrystals show a significant increase in fluorescence intensity, as compared to pure CdSe nanocrystals. We also observe a switching from n- to p-type doping in the silver-doped CdSe nanocrystals with increased silver amounts. Moreover, the silver-doping results in a change in the conductance of both PbSe and CdSe nanocrystals and the magnitude of this change depends on the amount of silver incorporated into the nanocrystals. In the bulk, silver chalcogenides (Ag2E, E=S, Se, and Te) possess a wide array of intriguing properties, including superionic conductivity. In addition, they undergo a reversible temperature-dependent phase transition which induces significant changes in their electronic and ionic properties. While most of these properties have been examined extensively in bulk, very few studies have been conducted at the nanoscale. We have recently developed a versatile synthesis that yields colloidal silver chalcogenide nanocrystals. Here, we study the size dependence of their phase-transition temperatures. We utilize differential scanning calorimetry and in-situ X-ray diffraction analyses to observe the phase transition in nanocrystal assemblies. We observe a significant deviation from the bulk alpha (low-temperature) to beta (high-temperature) phase-transition temperature when we reduce their size to a few nanometers. Hence, these nanocrystals provide great

  9. Fibrous guided tissue regeneration membrane loaded with anti-inflammatory agent prepared by coaxial electrospinning for the purpose of controlled release

    NASA Astrophysics Data System (ADS)

    He, Min; Xue, Jiajia; Geng, Huan; Gu, Hao; Chen, Dafu; Shi, Rui; Zhang, Liqun

    2015-04-01

    Here, with the aim of inhibiting inflammation during guided tissue regeneration membrane (GTRM) implant surgery, coaxial electrospinning was used to fabricate drug-loaded core/sheath nanofiber GTRMs capable of controlled drug release. Various amounts of the anti-inflammatory agent metronidazole (MNA) were encapsulated into the core/sheath nanofibers (where PCL was the core, gelatin the sheath, and the gelatin shell was crosslinked with genipin) in order to establish the minimal drug content necessary to achieve the appropriate anti-inflammatory effect. By using TEM and SEM, the core/sheath structure was confirmed. In vitro drug disolution results showed that the core/sheath nanofibers exhibited sustained release profiles that were superior to those nanofibers produced by blending electrospinning. Additionally, the membrane significantly inhibited the colonization of anaerobic bacteria. Furthermore, with gelatin as a shell, the core/shell nanofiber membranes showed improved hydrophilicity, which resulted in better cell adhesion and proliferation without cytotoxicity. Therefore, in this study, a simple and effective coaxial electrospinning approach was demonstrated for the fabrication of anti-inflammatory GTRMs capable of providing controlled drug release.

  10. Significant improvement in electronic properties of transparent amorphous indium zinc oxide through yttrium doping

    NASA Astrophysics Data System (ADS)

    Sun, Jian; Yu, Zhigen; Huang, Yanhua; Xia, Yijie; Lai, Weng Soon; Gong, Hao

    2014-04-01

    One big challenge in transparent conducting oxides (TCOs) is to achieve high conductivity and mobility at a low processing temperature. Although optimized conductivity has been achieved in indium zinc oxide (IZO) without doping, it is still interesting to find whether doping can improve conductivity of IZO further. In this paper, we report a low processing temperature achievement of high conductivity and mobility of IZO through yttrium (Y) doping. We found that with different Y doping levels, room temperature fabricated amorphous IZO (a-IZO) samples can be controlled to exhibit either metallic or semiconductor characteristics. Y2O3 is demonstrated to be an effective doping source to achieve conductivity 300% higher than the non-doped IZO sample. Anomalously improved mobility of certain Y2O3-doped IZO samples compared with the non-doped IZO sample is found and analyzed. Besides, a low-temperature resistivity anomaly (semiconductor metal transition) phenomenon is observed and discussed.

  11. Gene doping in sport - perspectives and risks.

    PubMed

    Brzeziańska, E; Domańska, D; Jegier, A

    2014-12-01

    In the past few years considerable progress regarding the knowledge of the human genome map has been achieved. As a result, attempts to use gene therapy in patients' management are more and more often undertaken. The aim of gene therapy is to replace defective genes in vivo and/or to promote the long-term endogenous synthesis of deficient protein. In vitro studies improve the production of human recombinant proteins, such as insulin (INS), growth hormone (GH), insulin-like growth factor-1 (IGF-1) and erythropoietin (EPO), which could have therapeutic application. Unfortunately, genetic methods developed for therapeutic purposes are increasingly being used in competitive sports. Some new substances (e.g., antibodies against myostatin or myostatin blockers) might be used in gene doping in athletes. The use of these substances may cause an increase of body weight and muscle mass and a significant improvement of muscle strength. Although it is proven that uncontrolled manipulation of genetic material and/or the introduction of recombinant proteins may be associated with health risks, athletes are increasingly turning to banned gene doping. At the same time, anti-doping research is undertaken in many laboratories around the world to try to develop and refine ever newer techniques for gene doping detection in sport. Thanks to the World Anti-Doping Agency (WADA) and other sports organizations there is a hope for real protection of athletes from adverse health effects of gene doping, which at the same time gives a chance to sustain the idea of fair play in sport.

  12. Phosphorus-doped and undoped glassy carbon indicator electrodes in controlled-current potentiometric titrations of bromide- or chloride-containing active ingredients in some pharmaceutical preparations.

    PubMed

    Abramović, Biljana F; Guzsvány, Valéria J; Gaál, Ferenc F

    2005-02-23

    Phosphorus-doped glassy carbon (as a novel material) and glassy carbon (Sigri commercial sample) were applied as potentiometric indicator electrodes in the titrimetric determination of active components with bromide or chloride in their molecules in different pharmaceutical preparations (Buscopan, Prostigmine, Isoptin, Bedoxin, Akineton and Trodon). After the necessary pre-treatment of the electrode surfaces and sample dissolution, the halide was titrated with a standard solution of silver nitrate (indirect determination). Amounts of 10-20 micromol of the investigated active ingredients per titration were determined with a relative standard deviation that, depending on the nature of indicator electrode, determined molecules and filler components, was in the range of 0.3-2.7%. The results obtained were compared with those of the official methods and with those obtained by potentiometric titrations using silver electrode. The titrimetric procedures developed are relatively fast, easy, economical and can be used to analyse of a large number of pharmaceutical products.

  13. Growth of pure and tin-doped indium oxide crystals and their electrical properties

    SciTech Connect

    Shimado, S.; Kodaira, K.; Sato, I.; Matsushita, T.

    1988-12-01

    Indium oxide, In/sub 2/O/sub 3/, is an n-type semiconductor with the C-type oxide structure. Its electrical resistivity is greatly decreased by doping with Sn, so that Sn-doped In/sub 2/O/sub 3/(ITO) thin films are widely used as transparent conductive coating and as heat reflection filters. Single crystals of In/sub 2/O/sub 3/ have been grown by vapor phase, flux, chemical transport or hydrothermal method, but only one growth experiment by a vapor phase method has been reported and no growth experiment of Sn-doped In/sub 2/O/sub 3/ crystals from the vapor phase has been carried out. The authors have brown the In/sub 2/O/sub 3/ crystals by the vapor method, one of which utilized air-oxidation of indium or In/sub 2/O vapors which are produced by reduction of In/sub 2/O/sub 3/ with carbon in a closed crucible. With this growth experiment it was, however, difficult to control the crystallization of In/sub 2/O/sub 3/ since the generation of In/sub 2/O or In vapors and oxidation of their vapors by air spontaneously occur in the crucible. The successful growth experiments for ZnP, GeO/sub 2/ and CdO crystals have been performed using the sophisticated method of controlling air-oxidation of Zn, GeO, and Cd vapors, respectively, which are generated by reduction of the oxides with carbon. The purpose of the present paper is to perform the prolonged growth of pure and Sn-doped In/sub 2/O/sub 3/ crystals by utilizing such a controlled reduction-oxidation process and investigating their electrical properties.

  14. Methods for Doping Detection.

    PubMed

    Ponzetto, Federico; Giraud, Sylvain; Leuenberger, Nicolas; Boccard, Julien; Nicoli, Raul; Baume, Norbert; Rudaz, Serge; Saugy, Martial

    2016-01-01

    Over the past few years, the World Anti-Doping Agency (WADA) has focused its efforts on detecting not only small prohibited molecules, but also larger endogenous molecules such as hormones, in the view of implementing an endocrinological module in the Athlete Biological Passport (ABP). In this chapter, the detection of two major types of hormones used for doping, growth hormone (GH) and endogenous anabolic androgenic steroids (EAASs), will be discussed: a brief historical background followed by a description of state-of-the-art methods applied by accredited anti-doping laboratories will be provided and then current research trends outlined. In addition, microRNAs (miRNAs) will also be presented as a new class of biomarkers for doping detection. PMID:27348309

  15. Evidence of Fermi level control in a half-metallic Heusler compound Co2MnSi by Al-doping: Comparison of measurements with first-principles calculations

    NASA Astrophysics Data System (ADS)

    Sakuraba, Y.; Takanashi, K.; Kota, Y.; Kubota, T.; Oogane, M.; Sakuma, A.; Ando, Y.

    2010-04-01

    The Fermi level (EF) control of half-metallic Heusler alloy Co2MnSi by Al-doping was challenged in magnetic tunnel junctions with a Co2MnAlxSi1-x (CMAS) electrode. The observed bias voltage dependence on tunneling conductance ( G-V curves) clearly shows a shift in EF toward the center of the half-metallic gap with x , which showed excellent agreement with our first-principles calculations. However, the ratio of tunnel magnetoresistance (TMR) at 10 K to that at room temperature does not exhibit a remarkable change with x . The weak exchange energy at the CMAS interface may be the origin for the large temperature dependence of the TMR ratio.

  16. Ultrathin Ca-PO4-CO3 solid-solution nanowires: a controllable synthesis and full-color emission by rare-earth doping.

    PubMed

    Hui, Junfeng; Yu, Qiyu; Long, Yong; Zhang, Zhicheng; Yang, Yong; Wang, Pengpeng; Xu, Biao; Wang, Xun

    2012-10-22

    It was found that calcium carbonate (CaCO(3)) and hydroxyapatite (Ca(10)(OH)(2)(PO(4))(6)), which are two crucial constituents of the most abundant minerals in nature and very important bioinorganic components in the tissues of mineralizing organisms, can form solid solutions in a wide range of PO(4)(3-)/CO(3)(2-) (P/C) ratios at low temperature when prepared as ultrathin nanowire structures. This is due to the special reactivity of ultrasmall nanocrystals, which can effectively lower the synthetic temperature and promote the formation of solid solutions. The as-prepared ultrathin nanowires with suitable P/C ratios presented strong blue luminescence due to the existence of abundant defects strengthened by CO(3)(2-). If used as the matrix, the as-prepared ultrathin nanowires demonstrated bright green or red luminescent properties when doped with Tb(3+) or Eu(3+) ions, and simultaneously retained their original morphologies. These three kinds of fluorescent nanowires could reproduce a full range of luminescence colors based on additive color mixtures of the three primary colors (red, green, and blue). In addition, under the same reaction system, ultrafine rare-earth-doped (Ce(3+), Tb(3+), Eu(3+)) nanowires (about 1 nm in diameter) were synthesized by using a one-step hydrothermal process, which further pushed the size of the Ca-PO(4)-CO(3) nanobuilding blocks to one unit cell region. These ultrafine nanowires displayed excellent film-forming properties and the ability to absorb UV radiation.

  17. [Blood doping: 2].

    PubMed

    Cristani, Alessandro; Boldrini, Elena; Amateis, Elisa; Arioli, Dimitriy

    2005-01-01

    Blood Doping has recently obtained a large diffusion between professional and nonprofessional athletes, in particular for endurance sports it has almost become a necessary way to warrant best performance. Seven years after the publication of our article "Blood Doping", this second installment was born to emphasize the way the biomedical research supplies (often unintentionally) new drugs and new technology to improve athletic performance and, on the other hand, to underline the antidoping strategies.

  18. 43 CFR 4700.0-1 - Purpose.

    Code of Federal Regulations, 2011 CFR

    2011-10-01

    ... OF THE INTERIOR RANGE MANAGEMENT (4000) PROTECTION, MANAGEMENT, AND CONTROL OF WILD FREE-ROAMING HORSES AND BURROS General § 4700.0-1 Purpose. The purpose of these regulations is to implement the laws relating to the protection, management, and control of wild horses and burros under the administration...

  19. 43 CFR 4700.0-1 - Purpose.

    Code of Federal Regulations, 2013 CFR

    2013-10-01

    ... OF THE INTERIOR RANGE MANAGEMENT (4000) PROTECTION, MANAGEMENT, AND CONTROL OF WILD FREE-ROAMING HORSES AND BURROS General § 4700.0-1 Purpose. The purpose of these regulations is to implement the laws relating to the protection, management, and control of wild horses and burros under the administration...

  20. 43 CFR 4700.0-1 - Purpose.

    Code of Federal Regulations, 2012 CFR

    2012-10-01

    ... OF THE INTERIOR RANGE MANAGEMENT (4000) PROTECTION, MANAGEMENT, AND CONTROL OF WILD FREE-ROAMING HORSES AND BURROS General § 4700.0-1 Purpose. The purpose of these regulations is to implement the laws relating to the protection, management, and control of wild horses and burros under the administration...

  1. 43 CFR 4700.0-1 - Purpose.

    Code of Federal Regulations, 2014 CFR

    2014-10-01

    ... OF THE INTERIOR RANGE MANAGEMENT (4000) PROTECTION, MANAGEMENT, AND CONTROL OF WILD FREE-ROAMING HORSES AND BURROS General § 4700.0-1 Purpose. The purpose of these regulations is to implement the laws relating to the protection, management, and control of wild horses and burros under the administration...

  2. 33 CFR 274.1 - Purpose.

    Code of Federal Regulations, 2010 CFR

    2010-07-01

    ... Navigation and Navigable Waters CORPS OF ENGINEERS, DEPARTMENT OF THE ARMY, DEPARTMENT OF DEFENSE PEST CONTROL PROGRAM FOR CIVIL WORKS PROJECTS Project Operation § 274.1 Purpose. The purpose of this regulation... pest control program at all civil works projects. It also presents guidance for the preparation...

  3. 44 CFR 2.1 - Purpose.

    Code of Federal Regulations, 2014 CFR

    2014-10-01

    ... 44 Emergency Management and Assistance 1 2014-10-01 2014-10-01 false Purpose. 2.1 Section 2.1 Emergency Management and Assistance FEDERAL EMERGENCY MANAGEMENT AGENCY, DEPARTMENT OF HOMELAND SECURITY GENERAL OMB CONTROL NUMBERS § 2.1 Purpose. This part collects and displays the control numbers assigned...

  4. 44 CFR 2.1 - Purpose.

    Code of Federal Regulations, 2013 CFR

    2013-10-01

    ... 44 Emergency Management and Assistance 1 2013-10-01 2013-10-01 false Purpose. 2.1 Section 2.1 Emergency Management and Assistance FEDERAL EMERGENCY MANAGEMENT AGENCY, DEPARTMENT OF HOMELAND SECURITY GENERAL OMB CONTROL NUMBERS § 2.1 Purpose. This part collects and displays the control numbers assigned...

  5. 44 CFR 2.1 - Purpose.

    Code of Federal Regulations, 2012 CFR

    2012-10-01

    ... 44 Emergency Management and Assistance 1 2012-10-01 2011-10-01 true Purpose. 2.1 Section 2.1 Emergency Management and Assistance FEDERAL EMERGENCY MANAGEMENT AGENCY, DEPARTMENT OF HOMELAND SECURITY GENERAL OMB CONTROL NUMBERS § 2.1 Purpose. This part collects and displays the control numbers assigned...

  6. 44 CFR 2.1 - Purpose.

    Code of Federal Regulations, 2011 CFR

    2011-10-01

    ... 44 Emergency Management and Assistance 1 2011-10-01 2011-10-01 false Purpose. 2.1 Section 2.1 Emergency Management and Assistance FEDERAL EMERGENCY MANAGEMENT AGENCY, DEPARTMENT OF HOMELAND SECURITY GENERAL OMB CONTROL NUMBERS § 2.1 Purpose. This part collects and displays the control numbers assigned...

  7. 33 CFR 153.101 - Purpose.

    Code of Federal Regulations, 2010 CFR

    2010-07-01

    ... Navigation and Navigable Waters COAST GUARD, DEPARTMENT OF HOMELAND SECURITY (CONTINUED) POLLUTION CONTROL OF POLLUTION BY OIL AND HAZARDOUS SUBSTANCES, DISCHARGE REMOVAL General § 153.101 Purpose. The purpose of this... hazardous substances as required by the Federal Water Pollution Control Act, as amended (FWPCA);...

  8. 33 CFR 153.101 - Purpose.

    Code of Federal Regulations, 2012 CFR

    2012-07-01

    ... Navigation and Navigable Waters COAST GUARD, DEPARTMENT OF HOMELAND SECURITY (CONTINUED) POLLUTION CONTROL OF POLLUTION BY OIL AND HAZARDOUS SUBSTANCES, DISCHARGE REMOVAL General § 153.101 Purpose. The purpose of this... hazardous substances as required by the Federal Water Pollution Control Act, as amended (FWPCA);...

  9. 33 CFR 153.101 - Purpose.

    Code of Federal Regulations, 2011 CFR

    2011-07-01

    ... Navigation and Navigable Waters COAST GUARD, DEPARTMENT OF HOMELAND SECURITY (CONTINUED) POLLUTION CONTROL OF POLLUTION BY OIL AND HAZARDOUS SUBSTANCES, DISCHARGE REMOVAL General § 153.101 Purpose. The purpose of this... hazardous substances as required by the Federal Water Pollution Control Act, as amended (FWPCA);...

  10. 33 CFR 153.101 - Purpose.

    Code of Federal Regulations, 2014 CFR

    2014-07-01

    ... Navigation and Navigable Waters COAST GUARD, DEPARTMENT OF HOMELAND SECURITY (CONTINUED) POLLUTION CONTROL OF POLLUTION BY OIL AND HAZARDOUS SUBSTANCES, DISCHARGE REMOVAL General § 153.101 Purpose. The purpose of this... hazardous substances as required by the Federal Water Pollution Control Act, as amended (FWPCA);...

  11. 33 CFR 153.101 - Purpose.

    Code of Federal Regulations, 2013 CFR

    2013-07-01

    ... Navigation and Navigable Waters COAST GUARD, DEPARTMENT OF HOMELAND SECURITY (CONTINUED) POLLUTION CONTROL OF POLLUTION BY OIL AND HAZARDOUS SUBSTANCES, DISCHARGE REMOVAL General § 153.101 Purpose. The purpose of this... hazardous substances as required by the Federal Water Pollution Control Act, as amended (FWPCA);...

  12. 44 CFR 2.1 - Purpose.

    Code of Federal Regulations, 2010 CFR

    2010-10-01

    ... 44 Emergency Management and Assistance 1 2010-10-01 2010-10-01 false Purpose. 2.1 Section 2.1 Emergency Management and Assistance FEDERAL EMERGENCY MANAGEMENT AGENCY, DEPARTMENT OF HOMELAND SECURITY GENERAL OMB CONTROL NUMBERS § 2.1 Purpose. This part collects and displays the control numbers assigned...

  13. 23 CFR 750.701 - Purpose.

    Code of Federal Regulations, 2010 CFR

    2010-04-01

    ... Outdoor Advertising Control § 750.701 Purpose. This subpart prescribes the Federal Highway Administration (FHWA) policies and requirements relating to the effective control of outdoor advertising under 23 U.S.C. 131. The purpose of these policies and requirements is to assure that there is effective State...

  14. 21 CFR 1402.1 - Purpose.

    Code of Federal Regulations, 2010 CFR

    2010-04-01

    ... 21 Food and Drugs 9 2010-04-01 2010-04-01 false Purpose. 1402.1 Section 1402.1 Food and Drugs OFFICE OF NATIONAL DRUG CONTROL POLICY MANDATORY DECLASSIFICATION REVIEW § 1402.1 Purpose. Other... files of the Office of National Drug Control Policy (ONDCP) be reviewed for possible...

  15. Spectroscopic investigation of nitrogen doped graphene

    SciTech Connect

    Podila, R.; Spear, J. T.; Chacon-Torres, J.; Pichler, T.; Ayala, P.; Rao, A. M.

    2012-09-17

    Current research efforts are aimed at controlling the electronic properties via doping graphene. Previously, dopant-induced changes in the Fermi velocity were observed to result in an effectively downshifted Raman peak below the G Prime -band for n-doped carbon nanotubes. However, in the case of N-doped graphene, we find that several Raman features vary depending upon both dopant concentration and its bonding environment. For instance, only pyridinic/pyrrolic dopants were observed to result in intense D/D Prime -bands with a concomitant downshift in the G Prime -band. Here, we correlate x-ray photoelectron measurements with Raman spectra to elucidate effects of dopant bonding configuration on vibrational properties of graphene.

  16. Marijuana as doping in sports.

    PubMed

    Campos, Daniel R; Yonamine, Mauricio; de Moraes Moreau, Regina L

    2003-01-01

    A high incidence of positive cases for cannabinoids, in analyses for doping control in sports, has been observed since the International Olympic Committee (IOC) included them in the 1989 list of prohibited drugs under the title of classes of prohibited substances in certain circumstances. Where the rules of sports federations so provide, tests are conducted for marijuana, hashish or any other cannabis product exposure by means of urinalysis of 11-nor-delta-9-tetrahydrocannabinol-9-carboxylic acid (carboxy-THC) the main metabolite of delta-9-tetrahydrocannabinol (THC). Concentrations >15 ng/mL (cut-off value) in confirmatory analytical procedures are considered doping. Cannabis is an illicit drug in several countries and has received much attention in the media for its potential therapeutic uses and the efforts to legalise its use. Studies have demonstrated that the use of cannabinoids can reduce anxiety, but it does not have ergogenic potential in sports activities. An increase in heart rate and blood pressure, decline of cardiac output and reduced psychomotor activity are some of the pharmacological effects of THC that will determine a decrease in athletic performance. An ergolytic activity of cannabis products has been observed in athletes of several different sport categories. In Brazil, analyses for doping control in sports, performed in our laboratories, have detected positive cases for carboxy-THC in urine samples of soccer, volleyball, cycling and other athletes. It is our intention to discuss in this article some points that may discourage individuals from using cannabis products during sports activities, even in the so-called permitted circumstances defined by the IOC and some sports federations. PMID:12744713

  17. Optical method for the screening of doping substances

    NASA Astrophysics Data System (ADS)

    Lademann, J.; Shevtsova, J.; Patzelt, A.; Richter, H.; Gladkowa, N. D.; Gelikonov, V. M.; Gonchukov, S. A.; Sterry, W.; Blume-Peytavi, U.

    2008-12-01

    During the last years, an increased misuse of doping substances in sport has been observed. The action of doping substances characterized by the stimulation of blood flow and metabolic processes is also reflected in the hair structure. In the present study it was demonstrated that optical coherent tomography is well suited for the analysis of hair parameters influenced by doping. Analyzing 20 patients, systemically treated with steroids which also represent doping substances, it was found that in all cases a significant increase in the cross-section of the hairs could be detected. The results obtained in the study are not only important for the screening of doping substances but also for medical diagnostics and control of compliance of patients.

  18. Manipulable MR effect in a δ-doped magnetic nanostructure

    NASA Astrophysics Data System (ADS)

    Kong, Yong-Hong; Jiang, Ya-Qing; Fu, Xi; Li, Ai-Hua

    2016-05-01

    A magnetoresistance (MR) device was proposed by depositing two nanosized ferromagnetic strips on top and bottom of the semiconductor heterostructure. For the sake of manipulating its performance, we introduce a tunable δ-potential into this device with the help of the atomic-layer doping technique such as molecular beam epitaxy (MBE) or metal-organic chemical-vapor deposition (MOCVD). We investigate theoretically the impact of the δ-doping on the magnetoresistance ratio (MMRR) of the MR device. Although the δ-doping is embedded in the device, a considerable MR effect still exists due to different transmissions for the electron across parallel (P) and antiparallel (AP) configurations. Moreover, its MMRR varies sensitively with the magnitude and/or position of the δ-doping. Such an MR device can be controlled by changing the δ-doping, resulting in an adjustable MR device for magnetoelectronics applications.

  19. Control of VO•• ˜ TiT i ' dipole pairs as well as M gTi ″ defects on dielectric properties of Mg doped (Pb0.35Sr0.65)TiO3 thin film

    NASA Astrophysics Data System (ADS)

    Hu, Tao; Wang, Zongrong; Ma, Ning; Du, Piyi

    2016-01-01

    Mg doped (Pb0.35Sr0.65)TiO3 (PST) thin films were fabricated on indium tin oxide /glass substrates by the sol-gel technique. The formation of the PST phase and control of the magnesium doping on the microstructure, defect states, and dielectric properties of the thin film were investigated by means of XRD, SEM, AFM, XPS, and impedance analysis. Results showed that the oxygen vacancies and the associated Ti3+ ions formed as VO•• ˜ TiT i ' dipole pairs, and the dipole pairs were aligned opposite to the direction of the intrinsic dipole moments in the PST thin film. The amount of dipole pairs was strongly affected by the formed M gTi ″ in the thin film. The minimum amount of the dipole pairs appeared in the PST thin film with Mg doping content of 6% in molar ratio. The thin film with Mg doping content of 6% showed high permittivity due to low offset from VO•• ˜ TiT i ' dipole pairs and low dielectric loss due to low defect electrons generated in the thin film simultaneously. The formed M gTi ″ in the oxygen octahedral contributed lower response of the dipole moments to external electric field and resulted in lower tunability of the PST thin film with increasing Mg doping content. Controlled by the substitution of Mg2+ ions for Ti4+ ions and the induced VO•• ˜ TiT i ' dipole pairs, the optimal figure of merit was obtained in the PST thin film with Mg doping content of 6% with which the thin film possessed the smallest dielectric loss and still high tunability simultaneously.

  20. Laser doping for high-efficiency silicon solar cells

    NASA Astrophysics Data System (ADS)

    Jäger, Ulrich; Wolf, Andreas; Steinhauser, Bernd; Benick, Jan; Nekarda, Jan; Preu, Ralf

    2012-10-01

    Selective laser doping is a versatile tool for the local adaption of doping profiles in a silicon substrate. By adjusting the laser fluence as well as the pulse width the maximum melt depth in the silicon can be controlled. Longer pulses lead to lower temperatures in the material and can help to enlarge the process window as ablation sets in at higher fluencies. For the fabrication of highly efficient silicon solar cells, laser doping can be used for efficiency improvement and process simplification. In passivated emitter and rear cells (PERC), selective laser doping can be used for selective emitter formation. Employing such a process, an efficiency boost of Δ ƞ= 0.4%abs was observed on commercial Cz-Si material. Laser doping was also used for process simplification for the fabrication of locally doped point contacts at the rear of a solar cell. A simple approach employing a doped passivation layer and a laser doping process allows for efficiencies beyond 22% on high quality n-type silicon.

  1. Enhanced angiogenesis and osteogenesis in critical bone defects by the controlled release of BMP-2 and VEGF: implantation of electron beam melting-fabricated porous Ti6Al4V scaffolds incorporating growth factor-doped fibrin glue.

    PubMed

    Lv, Jia; Xiu, Peng; Tan, Jie; Jia, Zhaojun; Cai, Hong; Liu, Zhongjun

    2015-06-24

    Electron beam melting (EBM)-fabricated porous titanium implants possessing low elastic moduli and tailored structures are promising biomaterials for orthopedic applications. However, the bio-inert nature of porous titanium makes reinforcement with growth factors (GFs) a promising method to enhance implant in vivo performance. Bone-morphogenic protein-2 (BMP-2) and vascular endothelial growth factor (VEGF) are key factors of angiogenesis and osteogenesis. Therefore, the present study is aimed at evaluating EBM-fabricated porous titanium implants incorporating GF-doped fibrin glue (FG) as composite scaffolds providing GFs for improvement of angiogenesis and osteogenesis in rabbit femoral condyle defects. BMP-2 and VEGF were added into the constituent compounds of FG, and then this GF-doped FG was subsequently injected into the porous scaffolds. In five groups of implants, angiogenesis and osteogenesis were evaluated at 4 weeks post-implantation using Microfil perfusion and histological analysis: eTi (empty scaffolds), cTi (containing undoped FG), BMP/cTi (containing 50 μg rhBMP-2), VEGF/cTi (containing 0.5 μg VEGF) and Dual/cTi (containing 50 μg rhBMP-2 and 0.5 μg VEGF). The results demonstrate that these composite implants are biocompatible and provide the desired gradual release of the bioactive growth factors. Incorporation of GF delivery, whether a single factor or dual factors, significantly enhanced both angiogenesis and osteogenesis inside the porous scaffolds. However, the synergistic effect of the dual factors combination was observable on angiogenesis but absent on osteogenesis. In conclusion, fibrin glue is a biocompatible material that could be employed as a delivery vehicle in EBM-fabricated porous titanium for controlled release of BMP-2 and VEGF. Application of this method for loading a porous titanium scaffold to incorporate growth factors is a convenient and promising strategy for improving osteogenesis of critical-sized bone defects.

  2. Simple quantitation of formoterol and 11-nor-Δ(9)-tetrahydrocannabinol-9-carboxylic acid in human urine by liquid chromatography-tandem mass spectrometry in doping control.

    PubMed

    Lee, Kang Mi; Kim, Ho Jun; Son, Junghyun; Park, Ju-Hyung; Kwon, Oh-Seung; Lee, Jaeick

    2014-09-15

    11-nor-Δ(9)-tetrahydrocannabinol-9-carboxylic acid (THC-COOH) and formoterol are newly revised prohibited threshold substances (150 ng/mL for THC-COOH and 40 ng/mL for formoterol) by the World Anti-Doping Agency (WADA). In continuation of our direct quantitation work of the prohibited threshold substances, direct LC-MS/MS methods combined with a simple sample preparation procedure have been developed and validated for the measurement of these two threshold substances in urine samples. After the enzymatic hydrolysis of urine samples, the resulting samples were diluted with acetonitrile and centrifuged. The supernatant was directly analyzed by LC-MS/MS using the selected reaction monitoring mode. The calibration curve range of the assay was ranged over 50-200% of the threshold value according to WADA guidelines. The limit of detection and limit of quantification were 6.1 and 18.4 ng/mL for THC-COOH and 2.0 and 6.2 ng/mL for formoterol, respectively. Intra- and inter-day precisions were between 2.08% and 7.28% and the accuracies ranged from 95.16% to 104.49%. The present methods were successfully applied to the analysis of the proficiency test samples. PMID:25063922

  3. Gate control of ferromagnetic insulating phase in lightly-doped La0.875Sr0.125MnO3-δ film

    NASA Astrophysics Data System (ADS)

    Kuang, H.; Wang, J.; Hu, F. X.; Zhao, Y. Y.; Liu, Y.; Wu, R. R.; Sun, J. R.; Shen, B. G.

    2016-02-01

    The electric field effect on the lightly doped La0.875Sr0.125MnO3-δ (LSMO) thin film in electric double-layer transistors was investigated by measuring transport properties of the film under various gate voltages. It was found that the positive gate bias leads to an increase of the charge-orbital ordering (COO) transition temperature and a decrease of the Curie temperature TC, indicating the suppression of ferromagnetic metal (FMM) phases and preference of COO/ferromagnetic insulator (FMI) with the hole depletion by gate bias. Such different electric field effects can be ascribed to the weakening of the ferromagnetic interaction and enhancement of Jahn-Teller (JT) distortion caused by the transformation of JT inactive Mn4+-ions to JT active Mn3+-ions. Moreover, a step-like increase in the high temperature region of the ρ-T curve, which is related to the transition of cooperative JT distortion, was found to develop with increasing the positive bias, indicating that the cooperative JT distorted phase is stabilized by the depletion of holes in LSMO film. These results demonstrate that the modulation of holes via electric field strongly affects the balance between energy gains of different interactions and thus produce different effects on the competing FMI, FMM, and cooperative JT distorted phases in LSMO film.

  4. Studies on the Controlling of the Microstructural and Morphological Properties of Al Doped ZnO Thin Films Prepared by Hydrothermal Method

    NASA Astrophysics Data System (ADS)

    Gil Gang, Myeng; Shin, Seung Wook; Gurav, K. V.; Wang, YinBo; Agawane, G. L.; Lee, Jeong Yong; Moon, Jong-Ha; Hyeok Kim, Jin

    2013-10-01

    Al doped ZnO (AZO) thin films were prepared on ZnO coated glass substrates by hydrothermal synthesis technique using aqueous solutions containing zinc nitrate hexahydrate, ammonium hydroxide, and different sodium citrate concentrations at 60 °C for 6 h. The effects of different trisodium citrate concentrations on the microstructural, crystallinity, morphological, optical, and chemical properties of thin films were investigated. X-ray diffraction studies showed that the AZO thin films were grown as a polycrystalline wurtzite hexagonal phase with a c-axis preferred orientation and without an unwanted second phase regardless of trisodium citrate concentrations. The thickness and grain sizes of AZO thin films decreased with increasing trisodium citrate concentration. The microstructure of AZO thin films was changed from flat to needle shaped and the morphology was smoother with increasing trisodium citrate concentrations. The AZO thin films have a high transmittance in the visible region ranging from 75 to 85% and a sharp edge from 366 to 374 nm.

  5. Detection of Stimulants and Narcotics by Liquid Chromatography-Tandem Mass Spectrometry and Gas Chromatography-Mass Spectrometry for Sports Doping Control.

    PubMed

    Ahrens, Brian D; Kucherova, Yulia; Butch, Anthony W

    2016-01-01

    Sports drug testing laboratories are required to detect several classes of compounds that are prohibited at all times, which include anabolic agents, peptide hormones, growth factors, beta-2 agonists, hormones and metabolic modulators, and diuretics/masking agents. Other classes of compounds such as stimulants, narcotics, cannabinoids, and glucocorticoids are also prohibited, but only when an athlete is in competition. A single class of compounds can contain a large number of prohibited substances and all of the compounds should be detected by the testing procedure. Since there are almost 70 stimulants on the prohibited list it can be a challenge to develop a single screening method that will optimally detect all the compounds. We describe a combined liquid chromatography-tandem mass spectrometry (LC-MS/MS) and gas chromatography-mass spectrometry (GC-MS) testing method for detection of all the stimulants and narcotics on the World Anti-Doping Agency prohibited list. Urine for LC-MS/MS testing does not require sample pretreatment and is a direct dilute and shoot method. Urine samples for the GC-MS method require a liquid-liquid extraction followed by derivatization with trifluoroacetic anhydride.

  6. Reading with Purpose

    ERIC Educational Resources Information Center

    Linderholm, Tracy

    2006-01-01

    In college-level courses, the vast majority of students read expository textbooks with a primary purpose in mind: to memorize and, hopefully, understand enough information to receive a particular grade on a course exam. Intuitively, this kind of reading is different than the kind of reading that these same students do when reading a novel while…

  7. Meaningful and Purposeful Practice

    ERIC Educational Resources Information Center

    Clementi, Donna

    2014-01-01

    This article describes a graphic, designed by Clementi and Terrill, the authors of "Keys to Planning for Learning" (2013), visually representing the components that contribute to meaningful and purposeful practice in learning a world language, practice that leads to greater proficiency. The entire graphic is centered around the letter…

  8. Spanish Special Purpose Dictionaries.

    ERIC Educational Resources Information Center

    Champion, James J.

    1982-01-01

    A variety of special purpose Spanish dictionaries available for students of Spanish are described, including dictionaries of groupings of associated words, technical language, regional and slang language, single authors' usage, historical periods, etymology, frequency, and reverse organization. Several illustrations of dictionary organization are…

  9. Purposes and Leadership.

    ERIC Educational Resources Information Center

    Gallin, Alice, Ed.

    1981-01-01

    Purposes and leadership in Catholic higher education are discussed to promote further dialogue among members of the Association of Catholic Colleges and Universities on institutional roots, present institutional conditions, and future vision. Papers and authors include: Commentary on Bishops' Pastoral Letter on Catholic Higher Education (William…

  10. Cu-Doping of ZnO by Nuclear Transmutation

    SciTech Connect

    Selim, F. A.; Tarun, M. C.; Wall, D. E.; Boatner, Lynn A; McCluskey, M. D.

    2011-01-01

    Zinc oxide single crystals were doped with copper acceptors by means of the nuclear transmutation doping (NTD) method, which gives highly uniform dopant distributions and has a much higher probability of controlling the dopant locations in the lattice. The Cu doping was confirmed by the infrared absorption signature of Cu2+ at 5780 cm-1. Hall-effect measurements were performed to study the effect of CuZn on the electrical properties of ZnO. These measurements indicated that the Cu acceptor level lies 0.126 eV below the conduction-band minimum.

  11. Controlling the growth morphology and phase segregation of Mn-doped Ga{sub 2}Se{sub 3} on Si(001).

    SciTech Connect

    Lovejoy, T. C.; Yitamben, E. N.; Heald, S. M.; Ohuchi, F. S.; Olmstead, M. A.

    2011-04-18

    The growth and phase segregation properties of the potential dilute magnetic semiconductor alloy (MnSe){sub x}(Ga{sub 2/3}Se){sub 1-x} are studied as a function of thickness, Mn concentration, postgrowth annealing, and the presence or absence of undoped Ga{sub 2}Se{sub 3} buffer and capping layers. This system is an unusual case in heteroepitaxy where two-phase MnSe{sup +}Ga{sub 2}Se{sub 3} has better lattice matching than the (MnSe){sub x}(Ga{sub 2/3}Se){sub 1-x} alloy. Despite this peculiarity, this system shows a modified form of Stranski-Krastonow growth: laminar films are observed up to a certain x-dependent critical thickness, above which islands are observed by scanning tunneling microscopy. The island morphology depends on the presence or absence of an undoped Ga{sub 2}Se{sub 3} buffer layer and postgrowth annealing. A kinetically stabilized platelet morphology is observed at the crossover point between laminar and islanded films. Based on Mn and Se K-edge extended x-ray absorption fine structure and x-ray absorption near-edge structure spectroscopy, there are two types of Mn in islanded films: Mn that remains doped in the Ga{sub 2}Se{sub 3} but oxidizes upon exposure to air, and Mn that participates in the islands, which are precipitates of the MnSe phase. Consistent with MnO or MnSe, L-edge x-ray absorption on air-exposed films suggests the Mn is in the formal +2 oxidation state. No L-edge x-ray magnetic circular dichroism signal is observed at 20 K, which may be due to surface effects or to a lack of magnetic order.

  12. Nanoparticle doping for improved Er-doped fiber lasers

    NASA Astrophysics Data System (ADS)

    Baker, Colin C.; Friebele, E. Joseph; Askins, Charles G.; Hunt, Michael P.; Marcheschi, Barbara A.; Fontana, Jake; Peele, John R.; Kim, Woohong; Sanghera, Jasbinder; Zhang, Jun; Pattnaik, Radha K.; Merkle, Larry D.; Dubinskii, Mark; Chen, Youming; Dajani, Iyad A.; Mart, Cody

    2016-03-01

    A nanoparticle (NP) doping technique was used for making erbium-doped fibers (EDFs) for high energy lasers. The nanoparticles were doped into the silica soot of preforms, which were drawn into fibers. The Er luminescence lifetimes of the NP-doped cores are longer than those of corresponding solution-doped silica, and substantially less Al is incorporated into the NP-doped cores. Optical-to-optical slope efficiencies of greater than 71% have been measured. Initial investigations of stimulated Brillouin scattering (SBS) have indicated that SBS suppression is achieved by NP doping, where we observed a low intrinsic Brillouin gain coefficient, of ~1× 10-11 m/W and the Brillouin bandwidth was increased by 2.5x compared to fused silica.

  13. Planar doped barrier subharmonic mixers

    NASA Technical Reports Server (NTRS)

    Lee, T. H.; East, J. R.; Haddad, G. I.

    1992-01-01

    The Planar Doped Barrier (PDB) diode is a device consisting of a p(+) doping spike between two intrinsic layers and n(+) ohmic contacts. This device has the advantages of controllable barrier height, diode capacitance and forward to reverse current ratio. A symmetrically designed PDB has an anti-symmetric current vs. voltage characteristic and is ideal for use as millimeter wave subharmonic mixers. We have fabricated such devices with barrier heights of 0.3, 0.5 and 0.7 volts from GaAs and InGaAs using a multijunction honeycomb structure with junction diameters between one and ten microns. Initial RF measurements are encouraging. The 0.7 volt barrier height 4 micron GaAs devices were tested as subharmonic mixers at 202 GHz with an IF frequency of 1 GHz and had 18 dB of conversion loss. The estimated mismatch loss was 7 dB and was due to higher diode capacitance. The LO frequency was 100.5 GHz and the pump power was 8 mW.

  14. Purposive discovery of operations

    NASA Technical Reports Server (NTRS)

    Sims, Michael H.; Bresina, John L.

    1992-01-01

    The Generate, Prune & Prove (GPP) methodology for discovering definitions of mathematical operators is introduced. GPP is a task within the IL exploration discovery system. We developed GPP for use in the discovery of mathematical operators with a wider class of representations than was possible with the previous methods by Lenat and by Shen. GPP utilizes the purpose for which an operator is created to prune the possible definitions. The relevant search spaces are immense and there exists insufficient information for a complete evaluation of the purpose constraint, so it is necessary to perform a partial evaluation of the purpose (i.e., pruning) constraint. The constraint is first transformed so that it is operational with respect to the partial information, and then it is applied to examples in order to test the generated candidates for an operator's definition. In the GPP process, once a candidate definition survives this empirical prune, it is passed on to a theorem prover for formal verification. We describe the application of this methodology to the (re)discovery of the definition of multiplication for Conway numbers, a discovery which is difficult for human mathematicians. We successfully model this discovery process utilizing information which was reasonably available at the time of Conway's original discovery. As part of this discovery process, we reduce the size of the search space from a computationally intractable size to 3468 elements.

  15. 40 CFR 210.1 - Purpose.

    Code of Federal Regulations, 2014 CFR

    2014-07-01

    ... 40 Protection of Environment 25 2014-07-01 2014-07-01 false Purpose. 210.1 Section 210.1 Protection of Environment ENVIRONMENTAL PROTECTION AGENCY (CONTINUED) NOISE ABATEMENT PROGRAMS PRIOR NOTICE OF CITIZEN SUITS § 210.1 Purpose. Section 12 of the Noise Control Act authorizes any person...

  16. 40 CFR 210.1 - Purpose.

    Code of Federal Regulations, 2010 CFR

    2010-07-01

    ... 40 Protection of Environment 24 2010-07-01 2010-07-01 false Purpose. 210.1 Section 210.1 Protection of Environment ENVIRONMENTAL PROTECTION AGENCY (CONTINUED) NOISE ABATEMENT PROGRAMS PRIOR NOTICE OF CITIZEN SUITS § 210.1 Purpose. Section 12 of the Noise Control Act authorizes any person...

  17. 40 CFR 210.1 - Purpose.

    Code of Federal Regulations, 2011 CFR

    2011-07-01

    ... 40 Protection of Environment 25 2011-07-01 2011-07-01 false Purpose. 210.1 Section 210.1 Protection of Environment ENVIRONMENTAL PROTECTION AGENCY (CONTINUED) NOISE ABATEMENT PROGRAMS PRIOR NOTICE OF CITIZEN SUITS § 210.1 Purpose. Section 12 of the Noise Control Act authorizes any person...

  18. 32 CFR 223.1 - Purpose.

    Code of Federal Regulations, 2014 CFR

    2014-07-01

    ... 32 National Defense 2 2014-07-01 2014-07-01 false Purpose. 223.1 Section 223.1 National Defense Department of Defense (Continued) OFFICE OF THE SECRETARY OF DEFENSE (CONTINUED) MISCELLANEOUS DOD UNCLASSIFIED CONTROLLED NUCLEAR INFORMATION (UCNI) § 223.1 Purpose. This part: (a) Updates policies,...

  19. 32 CFR 223.1 - Purpose.

    Code of Federal Regulations, 2010 CFR

    2010-07-01

    ... 32 National Defense 2 2010-07-01 2010-07-01 false Purpose. 223.1 Section 223.1 National Defense Department of Defense (Continued) OFFICE OF THE SECRETARY OF DEFENSE (CONTINUED) MISCELLANEOUS DEPARTMENT OF DEFENSE UNCLASSIFIED CONTROLLED NUCLEAR INFORMATION (DOD UCNI) § 223.1 Purpose. This part implements 10...

  20. 32 CFR 223.1 - Purpose.

    Code of Federal Regulations, 2013 CFR

    2013-07-01

    ... 32 National Defense 2 2013-07-01 2013-07-01 false Purpose. 223.1 Section 223.1 National Defense Department of Defense (Continued) OFFICE OF THE SECRETARY OF DEFENSE (CONTINUED) MISCELLANEOUS DOD UNCLASSIFIED CONTROLLED NUCLEAR INFORMATION (UCNI) § 223.1 Purpose. This part: (a) Updates policies,...

  1. 32 CFR 223.1 - Purpose.

    Code of Federal Regulations, 2012 CFR

    2012-07-01

    ... 32 National Defense 2 2012-07-01 2012-07-01 false Purpose. 223.1 Section 223.1 National Defense Department of Defense (Continued) OFFICE OF THE SECRETARY OF DEFENSE (CONTINUED) MISCELLANEOUS DEPARTMENT OF DEFENSE UNCLASSIFIED CONTROLLED NUCLEAR INFORMATION (DOD UCNI) § 223.1 Purpose. This part implements 10...

  2. 32 CFR 223.1 - Purpose.

    Code of Federal Regulations, 2011 CFR

    2011-07-01

    ... 32 National Defense 2 2011-07-01 2011-07-01 false Purpose. 223.1 Section 223.1 National Defense Department of Defense (Continued) OFFICE OF THE SECRETARY OF DEFENSE (CONTINUED) MISCELLANEOUS DEPARTMENT OF DEFENSE UNCLASSIFIED CONTROLLED NUCLEAR INFORMATION (DOD UCNI) § 223.1 Purpose. This part implements 10...

  3. 22 CFR 130.1 - Purpose.

    Code of Federal Regulations, 2010 CFR

    2010-04-01

    ... 22 Foreign Relations 1 2010-04-01 2010-04-01 false Purpose. 130.1 Section 130.1 Foreign Relations DEPARTMENT OF STATE INTERNATIONAL TRAFFIC IN ARMS REGULATIONS POLITICAL CONTRIBUTIONS, FEES AND COMMISSIONS § 130.1 Purpose. Section 39(a) of the Arms Export Control Act (22 U.S.C. 2779) provides that...

  4. 22 CFR 129.1 - Purpose.

    Code of Federal Regulations, 2011 CFR

    2011-04-01

    ... 22 Foreign Relations 1 2011-04-01 2011-04-01 false Purpose. 129.1 Section 129.1 Foreign Relations DEPARTMENT OF STATE INTERNATIONAL TRAFFIC IN ARMS REGULATIONS REGISTRATION AND LICENSING OF BROKERS § 129.1 Purpose. Section 38(b)(1)(A)(ii) of the Arms Export Control Act (22 U.S.C. 2778) provides that...

  5. 22 CFR 130.1 - Purpose.

    Code of Federal Regulations, 2011 CFR

    2011-04-01

    ... 22 Foreign Relations 1 2011-04-01 2011-04-01 false Purpose. 130.1 Section 130.1 Foreign Relations DEPARTMENT OF STATE INTERNATIONAL TRAFFIC IN ARMS REGULATIONS POLITICAL CONTRIBUTIONS, FEES AND COMMISSIONS § 130.1 Purpose. Section 39(a) of the Arms Export Control Act (22 U.S.C. 2779) provides that...

  6. 40 CFR 35.570 - Purpose.

    Code of Federal Regulations, 2012 CFR

    2012-07-01

    ... Tribe's jurisdiction. (c) Associated program regulations. Refer to 40 CFR parts 49, 50, 51, 52, 58, 60... 40 Protection of Environment 1 2012-07-01 2012-07-01 false Purpose. 35.570 Section 35.570... ASSISTANCE Environmental Program Grants for Tribes Air Pollution Control (section 105) § 35.570 Purpose....

  7. 40 CFR 35.570 - Purpose.

    Code of Federal Regulations, 2014 CFR

    2014-07-01

    ... Tribe's jurisdiction. (c) Associated program regulations. Refer to 40 CFR parts 49, 50, 51, 52, 58, 60... 40 Protection of Environment 1 2014-07-01 2014-07-01 false Purpose. 35.570 Section 35.570... ASSISTANCE Environmental Program Grants for Tribes Air Pollution Control (section 105) § 35.570 Purpose....

  8. 7 CFR 631.1 - Purpose.

    Code of Federal Regulations, 2011 CFR

    2011-01-01

    ... treatment of farm or ranch units with the most severe soil and water resources problems. The purpose of the... uses which are needed to conserve, develop, protect, and utilize the soil and water resources of their lands. This purpose is achieved by controlling erosion, conserving water, and adjusting land use...

  9. 7 CFR 631.1 - Purpose.

    Code of Federal Regulations, 2013 CFR

    2013-01-01

    ... treatment of farm or ranch units with the most severe soil and water resources problems. The purpose of the... uses which are needed to conserve, develop, protect, and utilize the soil and water resources of their lands. This purpose is achieved by controlling erosion, conserving water, and adjusting land use...

  10. 7 CFR 631.1 - Purpose.

    Code of Federal Regulations, 2012 CFR

    2012-01-01

    ... treatment of farm or ranch units with the most severe soil and water resources problems. The purpose of the... uses which are needed to conserve, develop, protect, and utilize the soil and water resources of their lands. This purpose is achieved by controlling erosion, conserving water, and adjusting land use...

  11. 38 CFR 1.670 - Purpose.

    Code of Federal Regulations, 2010 CFR

    2010-07-01

    ... 38 Pensions, Bonuses, and Veterans' Relief 1 2010-07-01 2010-07-01 false Purpose. 1.670 Section 1.670 Pensions, Bonuses, and Veterans' Relief DEPARTMENT OF VETERANS AFFAIRS GENERAL PROVISIONS Administrative Control of Funds § 1.670 Purpose. The following regulations establish a system of...

  12. 49 CFR 509.1 - Purpose.

    Code of Federal Regulations, 2011 CFR

    2011-10-01

    ... 49 Transportation 6 2011-10-01 2011-10-01 false Purpose. 509.1 Section 509.1 Transportation Other Regulations Relating to Transportation (Continued) NATIONAL HIGHWAY TRAFFIC SAFETY ADMINISTRATION, DEPARTMENT OF TRANSPORTATION OMB CONTROL NUMBERS FOR INFORMATION COLLECTION REQUIREMENTS § 509.1 Purpose. This part collects and displays the...

  13. Doping incorporation paths in catalyst-free Be-doped GaAs nanowires

    SciTech Connect

    Casadei, Alberto; Heiss, Martin; Colombo, Carlo; Ruelle, Thibaud; Fontcuberta i Morral, Anna; Krogstrup, Peter; Roehr, Jason A.; Upadhyay, Shivendra; Sorensen, Claus B.; Nygard, Jesper

    2013-01-07

    The incorporation paths of Be in GaAs nanowires grown by the Ga-assisted method in molecular beam epitaxy have been investigated by electrical measurements of nanowires with different doping profiles. We find that Be atoms incorporate preferentially via the nanowire side facets, while the incorporation path through the Ga droplet is negligible. We also show that Be can diffuse into the volume of the nanowire giving an alternative incorporation path. This work is an important step towards controlled doping of nanowires and will serve as a help for designing future devices based on nanowires.

  14. Dope, Fiends, and Myths.

    ERIC Educational Resources Information Center

    Reasons, Charles E.

    Since the social reality of the drug problem has largely emanated from the diffuse conceptions of the drug user, an analysis of the history of the "dope fiend" mythology is presented in this paper in an attempt to assess the manner in which certain publics are informed about the problem. A content analysis of drug-related imagery was made from…

  15. Doped zinc oxide microspheres

    DOEpatents

    Arnold, Jr., Wesley D.; Bond, Walter D.; Lauf, Robert J.

    1993-01-01

    A new composition and method of making same for a doped zinc oxide microsphere and articles made therefrom for use in an electrical surge arrestor which has increased solid content, uniform grain size and is in the form of a gel.

  16. Doped zinc oxide microspheres

    DOEpatents

    Arnold, W.D. Jr.; Bond, W.D.; Lauf, R.J.

    1993-12-14

    A new composition and method of making same for a doped zinc oxide microsphere and articles made therefrom for use in an electrical surge arrestor which has increased solid content, uniform grain size and is in the form of a gel. 4 figures.

  17. 32 CFR 809a.0 - Purpose.

    Code of Federal Regulations, 2010 CFR

    2010-07-01

    ... DISTURBANCE INTERVENTION AND DISASTER ASSISTANCE § 809a.0 Purpose. This part prescribes the commanders... controlling entry to those installations. It provides guidance for use of military personnel in...

  18. 32 CFR 809a.0 - Purpose.

    Code of Federal Regulations, 2011 CFR

    2011-07-01

    ... DISTURBANCE INTERVENTION AND DISASTER ASSISTANCE § 809a.0 Purpose. This part prescribes the commanders... controlling entry to those installations. It provides guidance for use of military personnel in...

  19. Morphology-controlled synthesis and novel microwave electromagnetic properties of hollow urchin-like chain Fe-doped MnO{sub 2} under 10 T high magnetic field

    SciTech Connect

    Yuping, Duan; Jia, Zhang; Hui, Jing; Shunhua, Liu

    2011-05-15

    Fe-doped MnO{sub 2} with a hollow sea urchin-like ball chain shape was first synthesized under a high magnetic field of 10 T. The formation mechanism was investigated and discussed in detail. The synthesized samples were characterized by XRD, SEM, TEM, EMPA, and vector network analysis. By doping MnO{sub 2} with Fe, the relative complex permittivity of MnO{sub 2} and its corresponding loss tangent clearly decreases, but its relative complex permeability and its corresponding loss tangent markedly increases. Moreover, the theoretically calculated values of reflection loss show that with increasing the Fe content, the as-prepared Fe-doped MnO{sub 2} exhibits good microwave absorption capability. -- Graphical Abstract: Fe-doped MnO{sub 2} with a hollow sea urchin-like ball chain shape was first synthesized in a high magnetic field of 10 T via a simple chemical process. Display Omitted Highlights: {yields} Fe-doped MnO{sub 2} with a hollow sea urchin-like ball chain shape was first synthesized. {yields} We investigated formation mechanism and electromagnetic properties of the Fe-doped MnO{sub 2}. {yields} By doping MnO{sub 2} with Fe, the electromagnetic properties are improved obviously.

  20. Q-switching of a thulium-doped fibre laser using a holmium-doped fibre saturable absorber

    SciTech Connect

    Sadovnikova, Ya E; Kamynin, V A; Kurkov, A S; Medvedkov, O I; Marakulin, A V; Minashina, L A

    2014-01-31

    We have proposed and demonstrated a new passively Q-switched thulium-doped fibre laser configuration. A distinctive feature of this configuration is the use of a heavily holmium-doped fibre for Q-switching. Lasing was obtained at 1.96 μm, with a pulse energy of 3 μJ and pulse duration of 600 ns. The highest pulse repetition rate was 80 kHz. (control of laser radiation parameters)