47 CFR 32.6212 - Digital electronic switching expense.

Code of Federal Regulations, 2010 CFR

2010-10-01

... with digital electronic switching equipment used to provide circuit switching. (c) This subaccount 6212... 47 Telecommunication 2 2010-10-01 2010-10-01 false Digital electronic switching expense. 32.6212... Digital electronic switching expense. (a) This account shall include expenses associated with digital...

47 CFR 32.6212 - Digital electronic switching expense.

Code of Federal Regulations, 2012 CFR

2012-10-01

... with digital electronic switching equipment used to provide circuit switching. (c) This subaccount 6212... 47 Telecommunication 2 2012-10-01 2012-10-01 false Digital electronic switching expense. 32.6212... Digital electronic switching expense. (a) This account shall include expenses associated with digital...

47 CFR 32.2212 - Digital electronic switching.

Code of Federal Regulations, 2012 CFR

2012-10-01

... shall include the original cost of digital electronic switching equipment used to provide circuit... electronic switching equipment used to provide both circuit and packet switching shall be recorded in the... 47 Telecommunication 2 2012-10-01 2012-10-01 false Digital electronic switching. 32.2212 Section...

47 CFR 32.2212 - Digital electronic switching.

Code of Federal Regulations, 2014 CFR

2014-10-01

... shall include the original cost of digital electronic switching equipment used to provide circuit... electronic switching equipment used to provide both circuit and packet switching shall be recorded in the... 47 Telecommunication 2 2014-10-01 2014-10-01 false Digital electronic switching. 32.2212 Section...

47 CFR 32.2212 - Digital electronic switching.

Code of Federal Regulations, 2011 CFR

2011-10-01

... shall include the original cost of digital electronic switching equipment used to provide circuit... electronic switching equipment used to provide both circuit and packet switching shall be recorded in the... 47 Telecommunication 2 2011-10-01 2011-10-01 false Digital electronic switching. 32.2212 Section...

47 CFR 32.2212 - Digital electronic switching.

Code of Federal Regulations, 2010 CFR

2010-10-01

... shall include the original cost of digital electronic switching equipment used to provide circuit... electronic switching equipment used to provide both circuit and packet switching shall be recorded in the... 47 Telecommunication 2 2010-10-01 2010-10-01 false Digital electronic switching. 32.2212 Section...

47 CFR 32.2212 - Digital electronic switching.

Code of Federal Regulations, 2013 CFR

2013-10-01

... shall include the original cost of digital electronic switching equipment used to provide circuit... electronic switching equipment used to provide both circuit and packet switching shall be recorded in the... 47 Telecommunication 2 2013-10-01 2013-10-01 false Digital electronic switching. 32.2212 Section...

MAPPER: high-throughput maskless lithography

NASA Astrophysics Data System (ADS)

Wieland, M. J.; de Boer, G.; ten Berge, G. F.; Jager, R.; van de Peut, T.; Peijster, J. J. M.; Slot, E.; Steenbrink, S. W. H. K.; Teepen, T. F.; van Veen, A. H. V.; Kampherbeek, B. J.

2009-03-01

Maskless electron beam lithography, or electron beam direct write, has been around for a long time in the semiconductor industry and was pioneered from the mid-1960s onwards. This technique has been used for mask writing applications as well as device engineering and in some cases chip manufacturing. However because of its relatively low throughput compared to optical lithography, electron beam lithography has never been the mainstream lithography technology. To extend optical lithography double patterning, as a bridging technology, and EUV lithography are currently explored. Irrespective of the technical viability of both approaches, one thing seems clear. They will be expensive [1]. MAPPER Lithography is developing a maskless lithography technology based on massively-parallel electron-beam writing with high speed optical data transport for switching the electron beams. In this way optical columns can be made with a throughput of 10-20 wafers per hour. By clustering several of these columns together high throughputs can be realized in a small footprint. This enables a highly cost-competitive alternative to double patterning and EUV alternatives. In 2007 MAPPER obtained its Proof of Lithography milestone by exposing in its Demonstrator 45 nm half pitch structures with 110 electron beams in parallel, where all the beams where individually switched on and off [2]. In 2008 MAPPER has taken a next step in its development by building several tools. The objective of building these tools is to involve semiconductor companies to be able to verify tool performance in their own environment. To enable this, the tools will have a 300 mm wafer stage in addition to a 110-beam optics column. First exposures at 45 nm half pitch resolution have been performed and analyzed. On the same wafer it is observed that all beams print and based on analysis of 11 beams the CD for the different patterns is within 2.2 nm from target and the CD uniformity for the different patterns is better than 2.8 nm.

Scalable Sub-micron Patterning of Organic Materials Toward High Density Soft Electronics.

PubMed

Kim, Jaekyun; Kim, Myung-Gil; Kim, Jaehyun; Jo, Sangho; Kang, Jingu; Jo, Jeong-Wan; Lee, Woobin; Hwang, Chahwan; Moon, Juhyuk; Yang, Lin; Kim, Yun-Hi; Noh, Yong-Young; Jaung, Jae Yun; Kim, Yong-Hoon; Park, Sung Kyu

2015-09-28

The success of silicon based high density integrated circuits ignited explosive expansion of microelectronics. Although the inorganic semiconductors have shown superior carrier mobilities for conventional high speed switching devices, the emergence of unconventional applications, such as flexible electronics, highly sensitive photosensors, large area sensor array, and tailored optoelectronics, brought intensive research on next generation electronic materials. The rationally designed multifunctional soft electronic materials, organic and carbon-based semiconductors, are demonstrated with low-cost solution process, exceptional mechanical stability, and on-demand optoelectronic properties. Unfortunately, the industrial implementation of the soft electronic materials has been hindered due to lack of scalable fine-patterning methods. In this report, we demonstrated facile general route for high throughput sub-micron patterning of soft materials, using spatially selective deep-ultraviolet irradiation. For organic and carbon-based materials, the highly energetic photons (e.g. deep-ultraviolet rays) enable direct photo-conversion from conducting/semiconducting to insulating state through molecular dissociation and disordering with spatial resolution down to a sub-μm-scale. The successful demonstration of organic semiconductor circuitry promise our result proliferate industrial adoption of soft materials for next generation electronics.

Scalable Sub-micron Patterning of Organic Materials Toward High Density Soft Electronics

NASA Astrophysics Data System (ADS)

Kim, Jaekyun; Kim, Myung-Gil; Kim, Jaehyun; Jo, Sangho; Kang, Jingu; Jo, Jeong-Wan; Lee, Woobin; Hwang, Chahwan; Moon, Juhyuk; Yang, Lin; Kim, Yun-Hi; Noh, Yong-Young; Yun Jaung, Jae; Kim, Yong-Hoon; Kyu Park, Sung

2015-09-01

The success of silicon based high density integrated circuits ignited explosive expansion of microelectronics. Although the inorganic semiconductors have shown superior carrier mobilities for conventional high speed switching devices, the emergence of unconventional applications, such as flexible electronics, highly sensitive photosensors, large area sensor array, and tailored optoelectronics, brought intensive research on next generation electronic materials. The rationally designed multifunctional soft electronic materials, organic and carbon-based semiconductors, are demonstrated with low-cost solution process, exceptional mechanical stability, and on-demand optoelectronic properties. Unfortunately, the industrial implementation of the soft electronic materials has been hindered due to lack of scalable fine-patterning methods. In this report, we demonstrated facile general route for high throughput sub-micron patterning of soft materials, using spatially selective deep-ultraviolet irradiation. For organic and carbon-based materials, the highly energetic photons (e.g. deep-ultraviolet rays) enable direct photo-conversion from conducting/semiconducting to insulating state through molecular dissociation and disordering with spatial resolution down to a sub-μm-scale. The successful demonstration of organic semiconductor circuitry promise our result proliferate industrial adoption of soft materials for next generation electronics.

History and modern applications of nano-composite materials carrying GA/cm2 current density due to a Bose-Einstein Condensate at room temperature produced by Focused Electron Beam Induced Processing for many extraordinary novel technical applications

NASA Astrophysics Data System (ADS)

Koops, Hans W. P.

2015-12-01

The discovery of Focused Electron Beam Induced Processing and early applications of this technology led to the possible use of a novel nanogranular material “Koops-GranMat®” using Pt/C and Au/C material. which carries at room temperature a current density > 50 times the current density which high TC superconductors can carry. The explanation for the characteristics of this novel material is given. This fact allows producing novel products for many applications using Dual Beam system having a gas supply and X.Y.T stream data programming and not using GDSII layout pattern control software. Novel products are possible for energy transportation. -distribution.-switching, photon-detection above 65 meV energy for very efficient energy harvesting, for bright field emission electron sources used for vacuum electronic devices like amplifiers for HF electronics, micro-tubes, 30 GHz to 6 THz switching amplifiers with signal to noise ratio >10(!), THz power sources up to 1 Watt, in combination with miniaturized vacuum pumps, vacuum gauges, IR to THz detectors, EUV- and X-Ray sources. Since focusing electron beam induced deposition works also at low energy, selfcloning multibeam-production machines for field emitter lamps, displays, multi-beam - lithography, - imaging, and - inspection, energy harvesting, and power distribution with switches controlling field-emitter arrays for KA of currents but with < 100 V switching voltage are possible. Finally the replacement of HTC superconductors and its applications by the Koops-GranMat® having Koops-Pairs at room temperature will allow the investigation devices similar to Josephson Junctions and its applications now called QUIDART (Quantum interference devices at Room Temperature). All these possibilities will support a revolution in the optical, electric, power, and electronic technology.

Interface and thickness dependent domain switching and stability in Mg doped lithium niobate

DOE PAGES

Neumayer, Sabine M.; Ivanov, Ilia N.; Manzo, Michele; ...

2015-12-08

Controlling ferroelectric switching in Mg doped lithium niobate (Mg: LN) is of fundamental importance for optical device and domain wall electronics applications that require precise domain patterns. Stable ferroelectric switching has been previously observed in undoped LN layers above proton exchanged (PE) phases that exhibit reduced polarization, whereas PE layers have been found to inhibit lateral domain growth. Here, Mg doping, which is known to significantly alter ferroelectric switching properties including coercive field and switching currents, is shown to inhibit domain nucleation and stability in Mg: LN above buried PE phases that allow for precise ferroelectric patterning via domain growthmore » control. Furthermore, piezoresponse force microscopy (PFM) and switching spectroscopy PFM reveal that the voltage at which polarization switches from the "up" to the "down" state increases with increasing thickness in pure Mg: LN, whereas the voltage required for stable back switching to the original "up" state does not exhibit this thickness dependence. This behavior is consistent with the presence of an internal frozen defect field. The inhibition of domain nucleation above PE interfaces, observed in this study, is a phenomenon that occurs in Mg: LN but not in undoped samples and is mainly ascribed to a remaining frozen polarization in the PE phase that opposes polarization reversal. This reduced frozen depolarization field in the PE phase also influences the depolarization field of the Mg: LN layer above due to the presence of uncompensated polarization charge at the PE-Mg: LN boundary. Furthermore, these alterations in internal electric fields within the sample cause long-range lattice distortions in Mg: LN via electromechanical coupling, which were corroborated with complimentary Raman measurements.« less

Interface and thickness dependent domain switching and stability in Mg doped lithium niobate

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

Neumayer, Sabine M.; Rodriguez, Brian J., E-mail: gallo@kth.se, E-mail: brian.rodriguez@ucd.ie; Conway Institute of Biomolecular and Biomedical Research, University College Dublin, Belfield, Dublin 4

2015-12-14

Controlling ferroelectric switching in Mg doped lithium niobate (Mg:LN) is of fundamental importance for optical device and domain wall electronics applications that require precise domain patterns. Stable ferroelectric switching has been previously observed in undoped LN layers above proton exchanged (PE) phases that exhibit reduced polarization, whereas PE layers have been found to inhibit lateral domain growth. Here, Mg doping, which is known to significantly alter ferroelectric switching properties including coercive field and switching currents, is shown to inhibit domain nucleation and stability in Mg:LN above buried PE phases that allow for precise ferroelectric patterning via domain growth control. Furthermore,more » piezoresponse force microscopy (PFM) and switching spectroscopy PFM reveal that the voltage at which polarization switches from the “up” to the “down” state increases with increasing thickness in pure Mg:LN, whereas the voltage required for stable back switching to the original “up” state does not exhibit this thickness dependence. This behavior is consistent with the presence of an internal frozen defect field. The inhibition of domain nucleation above PE interfaces, observed in this study, is a phenomenon that occurs in Mg:LN but not in undoped samples and is mainly ascribed to a remaining frozen polarization in the PE phase that opposes polarization reversal. This reduced frozen depolarization field in the PE phase also influences the depolarization field of the Mg:LN layer above due to the presence of uncompensated polarization charge at the PE-Mg:LN boundary. These alterations in internal electric fields within the sample cause long-range lattice distortions in Mg:LN via electromechanical coupling, which were corroborated with complimentary Raman measurements.« less

Scalable Sub-micron Patterning of Organic Materials Toward High Density Soft Electronics

PubMed Central

Kim, Jaekyun; Kim, Myung-Gil; Kim, Jaehyun; Jo, Sangho; Kang, Jingu; Jo, Jeong-Wan; Lee, Woobin; Hwang, Chahwan; Moon, Juhyuk; Yang, Lin; Kim, Yun-Hi; Noh, Yong-Young; Yun Jaung, Jae; Kim, Yong-Hoon; Kyu Park, Sung

2015-01-01

The success of silicon based high density integrated circuits ignited explosive expansion of microelectronics. Although the inorganic semiconductors have shown superior carrier mobilities for conventional high speed switching devices, the emergence of unconventional applications, such as flexible electronics, highly sensitive photosensors, large area sensor array, and tailored optoelectronics, brought intensive research on next generation electronic materials. The rationally designed multifunctional soft electronic materials, organic and carbon-based semiconductors, are demonstrated with low-cost solution process, exceptional mechanical stability, and on-demand optoelectronic properties. Unfortunately, the industrial implementation of the soft electronic materials has been hindered due to lack of scalable fine-patterning methods. In this report, we demonstrated facile general route for high throughput sub-micron patterning of soft materials, using spatially selective deep-ultraviolet irradiation. For organic and carbon-based materials, the highly energetic photons (e.g. deep-ultraviolet rays) enable direct photo-conversion from conducting/semiconducting to insulating state through molecular dissociation and disordering with spatial resolution down to a sub-μm-scale. The successful demonstration of organic semiconductor circuitry promise our result proliferate industrial adoption of soft materials for next generation electronics. PMID:26411932

Scalable sub-micron patterning of organic materials toward high density soft electronics

DOE PAGES

Kim, Jaekyun; Kim, Myung -Gil; Kim, Jaehyun; ...

2015-09-28

The success of silicon based high density integrated circuits ignited explosive expansion of microelectronics. Although the inorganic semiconductors have shown superior carrier mobilities for conventional high speed switching devices, the emergence of unconventional applications, such as flexible electronics, highly sensitive photosensors, large area sensor array, and tailored optoelectronics, brought intensive research on next generation electronic materials. The rationally designed multifunctional soft electronic materials, organic and carbon-based semiconductors, are demonstrated with low-cost solution process, exceptional mechanical stability, and on-demand optoelectronic properties. Unfortunately, the industrial implementation of the soft electronic materials has been hindered due to lack of scalable fine-patterning methods. Inmore » this report, we demonstrated facile general route for high throughput sub-micron patterning of soft materials, using spatially selective deep-ultraviolet irradiation. For organic and carbon-based materials, the highly energetic photons (e.g. deep-ultraviolet rays) enable direct photo-conversion from conducting/semiconducting to insulating state through molecular dissociation and disordering with spatial resolution down to a sub-μm-scale. As a result, the successful demonstration of organic semiconductor circuitry promise our result proliferate industrial adoption of soft materials for next generation electronics.« less

Evaluation of Two Statistical Methods Provides Insights into the Complex Patterns of Alternative Polyadenylation Site Switching

PubMed Central

Li, Jie; Li, Rui; You, Leiming; Xu, Anlong; Fu, Yonggui; Huang, Shengfeng

2015-01-01

Switching between different alternative polyadenylation (APA) sites plays an important role in the fine tuning of gene expression. New technologies for the execution of 3’-end enriched RNA-seq allow genome-wide detection of the genes that exhibit significant APA site switching between different samples. Here, we show that the independence test gives better results than the linear trend test in detecting APA site-switching events. Further examination suggests that the discrepancy between these two statistical methods arises from complex APA site-switching events that cannot be represented by a simple change of average 3’-UTR length. In theory, the linear trend test is only effective in detecting these simple changes. We classify the switching events into four switching patterns: two simple patterns (3’-UTR shortening and lengthening) and two complex patterns. By comparing the results of the two statistical methods, we show that complex patterns account for 1/4 of all observed switching events that happen between normal and cancerous human breast cell lines. Because simple and complex switching patterns may convey different biological meanings, they merit separate study. We therefore propose to combine both the independence test and the linear trend test in practice. First, the independence test should be used to detect APA site switching; second, the linear trend test should be invoked to identify simple switching events; and third, those complex switching events that pass independence testing but fail linear trend testing can be identified. PMID:25875641

Circuit with a Switch for Charging a Battery in a Battery Capacitor Circuit

NASA Technical Reports Server (NTRS)

Stuart, Thomas A. (Inventor); Ashtiani, Cyrus N. (Inventor)

2008-01-01

A circuit for charging a battery combined with a capacitor includes a power supply adapted to be connected to the capacitor, and the battery. The circuit includes an electronic switch connected to the power supply. The electronic switch is responsive to switch between a conducting state to allow current and a non-conducting state to prevent current flow. The circuit includes a control device connected to the switch and is operable to generate a control signal to continuously switch the electronic switch between the conducting and non-conducting states to charge the battery.

47 CFR 32.2211 - Non-digital switching.

Code of Federal Regulations, 2010 CFR

2010-10-01

... switching. (a) This account shall include: (1) Original cost of stored program control analog circuit-switching and associated equipment. (2) Cost of remote analog electronic circuit switches. (3) Original cost of non-electronic circuit-switching equipment such as Step-by-Step, Crossbar, and Other Electro...

47 CFR 32.2211 - Non-digital switching.

Code of Federal Regulations, 2013 CFR

2013-10-01

... switching. (a) This account shall include: (1) Original cost of stored program control analog circuit-switching and associated equipment. (2) Cost of remote analog electronic circuit switches. (3) Original cost of non-electronic circuit-switching equipment such as Step-by-Step, Crossbar, and Other Electro...

47 CFR 32.2211 - Non-digital switching.

Code of Federal Regulations, 2012 CFR

2012-10-01

... switching. (a) This account shall include: (1) Original cost of stored program control analog circuit-switching and associated equipment. (2) Cost of remote analog electronic circuit switches. (3) Original cost of non-electronic circuit-switching equipment such as Step-by-Step, Crossbar, and Other Electro...

47 CFR 32.2211 - Non-digital switching.

Code of Federal Regulations, 2011 CFR

2011-10-01

... switching. (a) This account shall include: (1) Original cost of stored program control analog circuit-switching and associated equipment. (2) Cost of remote analog electronic circuit switches. (3) Original cost of non-electronic circuit-switching equipment such as Step-by-Step, Crossbar, and Other Electro...

47 CFR 32.2211 - Non-digital switching.

Code of Federal Regulations, 2014 CFR

2014-10-01

... switching. (a) This account shall include: (1) Original cost of stored program control analog circuit-switching and associated equipment. (2) Cost of remote analog electronic circuit switches. (3) Original cost of non-electronic circuit-switching equipment such as Step-by-Step, Crossbar, and Other Electro...

Picosecond electric-field-induced threshold switching in phase-change materials [THz-induced threshold switching and crystallization of phase-change materials

DOE PAGES

Zalden, Peter; Shu, Michael J.; Chen, Frank; ...

2016-08-05

Many chalcogenide glasses undergo a breakdown in electronic resistance above a critical field strength. Known as threshold switching, this mechanism enables field-induced crystallization in emerging phase-change memory. Purely electronic as well as crystal nucleation assisted models have been employed to explain the electronic breakdown. Here, picosecond electric pulses are used to excite amorphous Ag 4In 3Sb 67Te 26. Field-dependent reversible changes in conductivity and pulse-driven crystallization are observed. The present results show that threshold switching can take place within the electric pulse on subpicosecond time scales—faster than crystals can nucleate. As a result, this supports purely electronic models of thresholdmore » switching and reveals potential applications as an ultrafast electronic switch.« less

Feasibility study of an integrated optic switching center. [satellite tracking application

NASA Technical Reports Server (NTRS)

1979-01-01

The design of a high data rate switching center for a satellite tracking station is discussed. The feasibility of a switching network using an integrated switching matrix is assessed. The preferred integrated optical switching scheme was found to be an electro-optic Bragg diffraction switch. To ascertain the advantages of the integrated optics switching center, its properties are compared to those of opto-electronic and to electronics switching networks.

Ferroelastic switching in a layered-perovskite thin film

PubMed Central

Wang, Chuanshou; Ke, Xiaoxing; Wang, Jianjun; Liang, Renrong; Luo, Zhenlin; Tian, Yu; Yi, Di; Zhang, Qintong; Wang, Jing; Han, Xiu-Feng; Van Tendeloo, Gustaaf; Chen, Long-Qing; Nan, Ce-Wen; Ramesh, Ramamoorthy; Zhang, Jinxing

2016-01-01

A controllable ferroelastic switching in ferroelectric/multiferroic oxides is highly desirable due to the non-volatile strain and possible coupling between lattice and other order parameter in heterostructures. However, a substrate clamping usually inhibits their elastic deformation in thin films without micro/nano-patterned structure so that the integration of the non-volatile strain with thin film devices is challenging. Here, we report that reversible in-plane elastic switching with a non-volatile strain of approximately 0.4% can be achieved in layered-perovskite Bi2WO6 thin films, where the ferroelectric polarization rotates by 90° within four in-plane preferred orientations. Phase-field simulation indicates that the energy barrier of ferroelastic switching in orthorhombic Bi2WO6 film is ten times lower than the one in PbTiO3 films, revealing the origin of the switching with negligible substrate constraint. The reversible control of the in-plane strain in this layered-perovskite thin film demonstrates a new pathway to integrate mechanical deformation with nanoscale electronic and/or magnetoelectronic applications. PMID:26838483

Ferroelastic switching in a layered-perovskite thin film

DOE PAGES

Wang, Chuanshou; Ke, Xiaoxing; Wang, Jianjun; ...

2016-02-03

Here, a controllable ferroelastic switching in ferroelectric/multiferroic oxides is highly desirable due to the non-volatile strain and possible coupling between lattice and other order parameter in heterostructures. However, a substrate clamping usually inhibits their elastic deformation in thin films without micro/nano-patterned structure so that the integration of the non-volatile strain with thin film devices is challenging. Here, we report that reversible in-plane elastic switching with a non-volatile strain of approximately 0.4% can be achieved in layered-perovskite Bi 2WO 6 thin films, where the ferroelectric polarization rotates by 90° within four in-plane preferred orientations. Phase-field simulation indicates that the energy barriermore » of ferroelastic switching in orthorhombic Bi 2WO 6 film is ten times lower than the one in PbTiO 3 films, revealing the origin of the switching with negligible substrate constraint. The reversible control of the in-plane strain in this layered-perovskite thin film demonstrates a new pathway to integrate mechanical deformation with nanoscale electronic and/or magnetoelectronic applications.« less

Auditory Multi-Stability: Idiosyncratic Perceptual Switching Patterns, Executive Functions and Personality Traits

PubMed Central

Farkas, Dávid; Denham, Susan L.; Bendixen, Alexandra; Tóth, Dénes; Kondo, Hirohito M.; Winkler, István

2016-01-01

Multi-stability refers to the phenomenon of perception stochastically switching between possible interpretations of an unchanging stimulus. Despite considerable variability, individuals show stable idiosyncratic patterns of switching between alternative perceptions in the auditory streaming paradigm. We explored correlates of the individual switching patterns with executive functions, personality traits, and creativity. The main dimensions on which individual switching patterns differed from each other were identified using multidimensional scaling. Individuals with high scores on the dimension explaining the largest portion of the inter-individual variance switched more often between the alternative perceptions than those with low scores. They also perceived the most unusual interpretation more often, and experienced all perceptual alternatives with a shorter delay from stimulus onset. The ego-resiliency personality trait, which reflects a tendency for adaptive flexibility and experience seeking, was significantly positively related to this dimension. Taking these results together we suggest that this dimension may reflect the individual’s tendency for exploring the auditory environment. Executive functions were significantly related to some of the variables describing global properties of the switching patterns, such as the average number of switches. Thus individual patterns of perceptual switching in the auditory streaming paradigm are related to some personality traits and executive functions. PMID:27135945

Picosecond Electric-Field-Induced Threshold Switching in Phase-Change Materials.

PubMed

Zalden, Peter; Shu, Michael J; Chen, Frank; Wu, Xiaoxi; Zhu, Yi; Wen, Haidan; Johnston, Scott; Shen, Zhi-Xun; Landreman, Patrick; Brongersma, Mark; Fong, Scott W; Wong, H-S Philip; Sher, Meng-Ju; Jost, Peter; Kaes, Matthias; Salinga, Martin; von Hoegen, Alexander; Wuttig, Matthias; Lindenberg, Aaron M

2016-08-05

Many chalcogenide glasses undergo a breakdown in electronic resistance above a critical field strength. Known as threshold switching, this mechanism enables field-induced crystallization in emerging phase-change memory. Purely electronic as well as crystal nucleation assisted models have been employed to explain the electronic breakdown. Here, picosecond electric pulses are used to excite amorphous Ag_{4}In_{3}Sb_{67}Te_{26}. Field-dependent reversible changes in conductivity and pulse-driven crystallization are observed. The present results show that threshold switching can take place within the electric pulse on subpicosecond time scales-faster than crystals can nucleate. This supports purely electronic models of threshold switching and reveals potential applications as an ultrafast electronic switch.

Self-marking phase-stepping electronic speckle pattern interfometry (ESPI) for 3D displacement measurement on cathode ray tube (CRT)-panels

NASA Astrophysics Data System (ADS)

Huang, M. J.; Liu, Zhao-Cheng; Jhang, Jhen-Huei

2002-11-01

This study demonstrates the feasibility of applying phase-shifting electronic speckle pattern interfometry to measure the deformation field of the front panel of a cathode ray tube, to support analysis to enhance the implosion-resistance capacity under violent collapse. Two effects, the air exhaustion and shrink band constraint effects, are comprehensively investigated. The angle of an adjustable mirror is switched, to provide three sensitivity vectors that are required in 3D-displacement measurement. A Fourier filtration is employed to remove speckle noise and establish a noise-free phase map. Inconsistent points are identified and masked to prevent any possible divergence during phase unwrapping. The results show that the accuracy of this method is satisfactory.

Programming Nanoparticles in Multiscale: Optically Modulated Assembly and Phase Switching of Silicon Nanoparticle Array.

PubMed

Wang, Letian; Rho, Yoonsoo; Shou, Wan; Hong, Sukjoon; Kato, Kimihiko; Eliceiri, Matthew; Shi, Meng; Grigoropoulos, Costas P; Pan, Heng; Carraro, Carlo; Qi, Dongfeng

2018-03-27

Manipulating and tuning nanoparticles by means of optical field interactions is of key interest for nanoscience and applications in electronics and photonics. We report scalable, direct, and optically modulated writing of nanoparticle patterns (size, number, and location) of high precision using a pulsed nanosecond laser. The complex nanoparticle arrangement is modulated by the laser pulse energy and polarization with the particle size ranging from 60 to 330 nm. Furthermore, we report fast cooling-rate induced phase switching of crystalline Si nanoparticles to the amorphous state. Such phase switching has usually been observed in compound phase change materials like GeSbTe. The ensuing modification of atomic structure leads to dielectric constant switching. Based on these effects, a multiscale laser-assisted method of fabricating Mie resonator arrays is proposed. The number of Mie resonators, as well as the resonance peaks and dielectric constants of selected resonators, can be programmed. The programmable light-matter interaction serves as a mechanism to fabricate optical metasurfaces, structural color, and multidimensional optical storage devices.

Tests of a low-pressure switch protected by a saturating inductor

NASA Astrophysics Data System (ADS)

Lauer, E. J.; Birx, D. L.

Low pressure switches and magnetic switches were tested as possible replacements for the high pressure switches currently used on Experimental Test Accelerator and Advanced Test Accelerator. When the low pressure switch is used with a low impedance transmission line, runaway electrons form a pinched electron beam which damages the anode. The use of the low pressure switch as the first switch in the pulsed power chain was tested; i.e., the switch would be used to connect a charged capacitor across the primary winding of a step up transformer. An inductor with a saturating core is connected in series so that, initially, there is a large inductive voltage drop. As a result, there is small voltage across the switch. By the time the inductor core saturates, the switch has developed sufficient ionization so that the switch voltage remains small, even with peak current, and an electron beam is not produced.

Organic solid state optical switches and method for producing organic solid state optical switches

DOEpatents

Wasielewski, M.R.; Gaines, G.L.; Niemczyk, M.P.; Johnson, D.G.; Gosztola, D.J.; O`Neil, M.P.

1993-01-01

This invention consists of a light-intensity dependent molecular switch comprised of a compound which shuttles an electron or a plurality of electrons from a plurality of electron donors to an electron acceptor upon being stimulated with light of predetermined wavelengths, and a method for making said compound.

Gait Analysis Laboratory

NASA Technical Reports Server (NTRS)

1976-01-01

Complete motion analysis laboratory has evolved out of analyzing walking patterns of crippled children at Stanford Children's Hospital. Data is collected by placing tiny electrical sensors over muscle groups of child's legs and inserting step-sensing switches in soles of shoes. Miniature radio transmitters send signals to receiver for continuous recording of abnormal walking pattern. Engineers are working to apply space electronics miniaturization techniques to reduce size and weight of telemetry system further as well as striving to increase signal bandwidth so analysis can be performed faster and more accurately using a mini-computer.

Software-defined networking control plane for seamless integration of multiple silicon photonic switches in Datacom networks.

PubMed

Shen, Yiwen; Hattink, Maarten H N; Samadi, Payman; Cheng, Qixiang; Hu, Ziyiz; Gazman, Alexander; Bergman, Keren

2018-04-16

Silicon photonics based switches offer an effective option for the delivery of dynamic bandwidth for future large-scale Datacom systems while maintaining scalable energy efficiency. The integration of a silicon photonics-based optical switching fabric within electronic Datacom architectures requires novel network topologies and arbitration strategies to effectively manage the active elements in the network. We present a scalable software-defined networking control plane to integrate silicon photonic based switches with conventional Ethernet or InfiniBand networks. Our software-defined control plane manages both electronic packet switches and multiple silicon photonic switches for simultaneous packet and circuit switching. We built an experimental Dragonfly network testbed with 16 electronic packet switches and 2 silicon photonic switches to evaluate our control plane. Observed latencies occupied by each step of the switching procedure demonstrate a total of 344 µs control plane latency for data-center and high performance computing platforms.

Electron-Impact-Ionization and Electron-Attachment Cross Sections of Radicals Important in Transient Gaseous Discharges.

DTIC Science & Technology

1988-02-05

for understanding the microscopic processes of electrical discharges and for designing gaseous discharge switches. High power gaseous discharge switches...half-maximum) energy resolution. The electron gun and ion extraction were of the same design of Srivastava at the Jet Propulsion Laboratory. Ions...photons. - The observed current switching can be applied to the design of discharge switches. Elec- tron transport parameters are needed for the

Organic solid state switches incorporating porphyrin compounds and method for producing organic solid state optical switches

DOEpatents

Wasielewski, Michael R.; Gaines, George L.; Niemczyk, Mark P.; Johnson, Douglas G.; Gosztola, David J.; O'Neil, Michael P.

1996-01-01

A light-intensity dependent molecular switch comprised of a compound which shuttles an electron or a plurality of electrons from a plurality of electron donors to an electron acceptor upon being stimulated with light of predetermined wavelengths, said donors selected from porphyrins and other compounds, and a method for making said compound.

TFT-Directed Electroplating of RGB Luminescent Films without a Vacuum or Mask toward a Full-Color AMOLED Pixel Matrix.

PubMed

Wang, Rong; Zhang, Donglian; Xiong, You; Zhou, Xuehong; Liu, Cao; Chen, Weifeng; Wu, Weijing; Zhou, Lei; Xu, Miao; Wang, Lei; Liu, Linlin; Peng, Junbiao; Ma, Yuguang; Cao, Yong

2018-05-30

The thin-film transistor (TFT) driving circuit is a separate electronic component embedded within the panel itself to switch the current for each pixel in active-matrix organic light-emitting diode displays. We reported a TFT-directed dye electroplating method to fabricate pixels; this would be a new method to deposit films on prepatterned electrode for organic full-color display, where TFT driving circuit provide a switching current signal to drive and direct dye depositing on selected RGB pixels. A prototype patterned color pixel matrix was achieved, as high-quality light-emitting films with uniform morphology, pure RGB chromaticity, and stable output.

Magneto-ionic control of interfacial magnetism

NASA Astrophysics Data System (ADS)

Bauer, Uwe; Yao, Lide; Tan, Aik Jun; Agrawal, Parnika; Emori, Satoru; Tuller, Harry L.; van Dijken, Sebastiaan; Beach, Geoffrey S. D.

2015-02-01

In metal/oxide heterostructures, rich chemical, electronic, magnetic and mechanical properties can emerge from interfacial chemistry and structure. The possibility to dynamically control interface characteristics with an electric field paves the way towards voltage control of these properties in solid-state devices. Here, we show that electrical switching of the interfacial oxidation state allows for voltage control of magnetic properties to an extent never before achieved through conventional magneto-electric coupling mechanisms. We directly observe in situ voltage-driven O2- migration in a Co/metal-oxide bilayer, which we use to toggle the interfacial magnetic anisotropy energy by >0.75 erg cm-2 at just 2 V. We exploit the thermally activated nature of ion migration to markedly increase the switching efficiency and to demonstrate reversible patterning of magnetic properties through local activation of ionic migration. These results suggest a path towards voltage-programmable materials based on solid-state switching of interface oxygen chemistry.

Characterising switching behaviour in perceptual multi-stability.

PubMed

Denham, Susan; Bendixen, Alexandra; Mill, Robert; Tóth, Dénes; Wennekers, Thomas; Coath, Martin; Bőhm, Tamás; Szalardy, Orsolya; Winkler, István

2012-09-15

When people experience an unchanging sensory input for a long period of time, their perception tends to switch stochastically and unavoidably between alternative interpretations of the sensation; a phenomenon known as perceptual bi-stability or multi-stability. The huge variability in the experimental data obtained in such paradigms makes it difficult to distinguish typical patterns of behaviour, or to identify differences between switching patterns. Here we propose a new approach to characterising switching behaviour based upon the extraction of transition matrices from the data, which provide a compact representation that is well-understood mathematically. On the basis of this representation we can characterise patterns of perceptual switching, visualise and simulate typical switching patterns, and calculate the likelihood of observing a particular switching pattern. The proposed method can support comparisons between different observers, experimental conditions and even experiments. We demonstrate the insights offered by this approach using examples from our experiments investigating multi-stability in auditory streaming. However, the methodology is generic and thus widely applicable in studies of multi-stability in any domain. Copyright © 2012 Elsevier B.V. All rights reserved.

Organic solid state switches incorporating porphyrin compounds and method for producing organic solid state optical switches

DOEpatents

Wasielewski, M.R.; Gaines, G.L.; Niemczyk, M.P.; Johnson, D.G.; Gosztola, D.J.; O`Neil, M.P.

1996-07-23

A light-intensity dependent molecular switch comprised of a compound which shuttles an electron or a plurality of electrons from a plurality of electron donors to an electron acceptor upon being stimulated with light of predetermined wavelengths, said donors selected from porphyrins and other compounds, and a method for making said compound are disclosed. 4 figs.

Self-Induced Switchings between Multiple Space-Time Patterns on Complex Networks of Excitable Units

NASA Astrophysics Data System (ADS)

Ansmann, Gerrit; Lehnertz, Klaus; Feudel, Ulrike

2016-01-01

We report on self-induced switchings between multiple distinct space-time patterns in the dynamics of a spatially extended excitable system. These switchings between low-amplitude oscillations, nonlinear waves, and extreme events strongly resemble a random process, although the system is deterministic. We show that a chaotic saddle—which contains all the patterns as well as channel-like structures that mediate the transitions between them—is the backbone of such a pattern-switching dynamics. Our analyses indicate that essential ingredients for the observed phenomena are that the system behaves like an inhomogeneous oscillatory medium that is capable of self-generating spatially localized excitations and that is dominated by short-range connections but also features long-range connections. With our findings, we present an alternative to the well-known ways to obtain self-induced pattern switching, namely, noise-induced attractor hopping, heteroclinic orbits, and adaptation to an external signal. This alternative way can be expected to improve our understanding of pattern switchings in spatially extended natural dynamical systems like the brain and the heart.

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

Kim, Jaekyun; Kim, Myung -Gil; Kim, Jaehyun

The success of silicon based high density integrated circuits ignited explosive expansion of microelectronics. Although the inorganic semiconductors have shown superior carrier mobilities for conventional high speed switching devices, the emergence of unconventional applications, such as flexible electronics, highly sensitive photosensors, large area sensor array, and tailored optoelectronics, brought intensive research on next generation electronic materials. The rationally designed multifunctional soft electronic materials, organic and carbon-based semiconductors, are demonstrated with low-cost solution process, exceptional mechanical stability, and on-demand optoelectronic properties. Unfortunately, the industrial implementation of the soft electronic materials has been hindered due to lack of scalable fine-patterning methods. Inmore » this report, we demonstrated facile general route for high throughput sub-micron patterning of soft materials, using spatially selective deep-ultraviolet irradiation. For organic and carbon-based materials, the highly energetic photons (e.g. deep-ultraviolet rays) enable direct photo-conversion from conducting/semiconducting to insulating state through molecular dissociation and disordering with spatial resolution down to a sub-μm-scale. As a result, the successful demonstration of organic semiconductor circuitry promise our result proliferate industrial adoption of soft materials for next generation electronics.« less

Software-defined networking control plane for seamless integration of multiple silicon photonic switches in Datacom networks

DOE PAGES

Shen, Yiwen; Hattink, Maarten; Samadi, Payman; ...

2018-04-13

Silicon photonics based switches offer an effective option for the delivery of dynamic bandwidth for future large-scale Datacom systems while maintaining scalable energy efficiency. The integration of a silicon photonics-based optical switching fabric within electronic Datacom architectures requires novel network topologies and arbitration strategies to effectively manage the active elements in the network. Here, we present a scalable software-defined networking control plane to integrate silicon photonic based switches with conventional Ethernet or InfiniBand networks. Our software-defined control plane manages both electronic packet switches and multiple silicon photonic switches for simultaneous packet and circuit switching. We built an experimental Dragonfly networkmore » testbed with 16 electronic packet switches and 2 silicon photonic switches to evaluate our control plane. Observed latencies occupied by each step of the switching procedure demonstrate a total of 344 microsecond control plane latency for data-center and high performance computing platforms.« less

Software-defined networking control plane for seamless integration of multiple silicon photonic switches in Datacom networks

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

Shen, Yiwen; Hattink, Maarten; Samadi, Payman

Silicon photonics based switches offer an effective option for the delivery of dynamic bandwidth for future large-scale Datacom systems while maintaining scalable energy efficiency. The integration of a silicon photonics-based optical switching fabric within electronic Datacom architectures requires novel network topologies and arbitration strategies to effectively manage the active elements in the network. Here, we present a scalable software-defined networking control plane to integrate silicon photonic based switches with conventional Ethernet or InfiniBand networks. Our software-defined control plane manages both electronic packet switches and multiple silicon photonic switches for simultaneous packet and circuit switching. We built an experimental Dragonfly networkmore » testbed with 16 electronic packet switches and 2 silicon photonic switches to evaluate our control plane. Observed latencies occupied by each step of the switching procedure demonstrate a total of 344 microsecond control plane latency for data-center and high performance computing platforms.« less

Pattern Switchable Antenna System Using Inkjet-Printed Directional Bow-Tie for Bi-Direction Sensing Applications

PubMed Central

Eom, Seung-Hyun; Seo, Yunsik; Lim, Sungjoon

2015-01-01

In this paper, we propose a paper-based pattern switchable antenna system using inkjet-printing technology for bi-direction sensor applications. The proposed antenna system is composed of two directional bow-tie antennas and a switching network. The switching network consists of a single-pole-double-throw (SPDT) switch and a balun element. A double-sided parallel-strip line (DSPSL) is employed to convert the unbalanced microstrip mode to the balanced strip mode. Two directional bow-tie antennas have different radiation patterns because of the different orientation of the reflectors and antennas. It is demonstrated from electromagnetic (EM) simulation and measurement that the radiation patterns of the proposed antenna are successfully switched by the SPDT switch. PMID:26690443

Pattern Switchable Antenna System Using Inkjet-Printed Directional Bow-Tie for Bi-Direction Sensing Applications.

PubMed

Eom, Seung-Hyun; Seo, Yunsik; Lim, Sungjoon

2015-12-10

In this paper, we propose a paper-based pattern switchable antenna system using inkjet-printing technology for bi-direction sensor applications. The proposed antenna system is composed of two directional bow-tie antennas and a switching network. The switching network consists of a single-pole-double-throw (SPDT) switch and a balun element. A double-sided parallel-strip line (DSPSL) is employed to convert the unbalanced microstrip mode to the balanced strip mode. Two directional bow-tie antennas have different radiation patterns because of the different orientation of the reflectors and antennas. It is demonstrated from electromagnetic (EM) simulation and measurement that the radiation patterns of the proposed antenna are successfully switched by the SPDT switch.

Switching behaviour of individual Ag-TCNQ nanowires: an in situ transmission electron microscopy study

NASA Astrophysics Data System (ADS)

Ran, Ke; Rösner, Benedikt; Butz, Benjamin; Fink, Rainer H.; Spiecker, Erdmann

2016-10-01

The organic semiconductor silver-tetracyanoquinodimethane (Ag-TCNQ) exhibits electrical switching and memory characteristics. Employing a scanning tunnelling microscopy setup inside a transmission electron microscope, the switching behaviour of individual Ag-TCNQ nanowires (NWs) is investigated in detail. For a large number of NWs, the switching between a high (OFF) and a low (ON) resistance state was successfully stimulated by negative bias sweeps. Fitting the experimental I-V curves with a Schottky emission function makes the switching features prominent and thus enables a direct evaluation of the switching process. A memory cycle including writing, reading and erasing features is demonstrated at an individual NW. Moreover, electronic failure mechanisms due to Joule heating are discussed. These findings have a significant impact on our understanding of the switching behaviour of Ag-TCNQ.

Electronic switching circuit uses complementary non-linear components

NASA Technical Reports Server (NTRS)

Zucker, O. S.

1972-01-01

Inherent switching properties of saturable inductors and storage diodes are combined to perform large variety of electronic functions, such as pulse shaping, gating, and multiplexing. Passive elements replace active switching devices in generation of complex waveforms.

Triggered plasma opening switch

DOEpatents

Mendel, Clifford W.

1988-01-01

A triggerable opening switch for a very high voltage and current pulse includes a transmission line extending from a source to a load and having an intermediate switch section including a plasma for conducting electrons between transmission line conductors and a magnetic field for breaking the plasma conduction path and magnetically insulating the electrons when it is desired to open the switch.

Thickness, humidity, and polarization dependent ferroelectric switching and conductivity in Mg doped lithium niobate

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

Neumayer, Sabine M.; Rodriguez, Brian J., E-mail: brian.rodriguez@ucd.ie; Conway Institute of Biomolecular and Biomedical Research, University College Dublin, Belfield, Dublin 4

2015-12-28

Mg doped lithium niobate (Mg:LN) exhibits several advantages over undoped LN such as resistance to photorefraction, lower coercive fields, and p-type conductivity that is particularly pronounced at domain walls and opens up a range of applications, e.g., in domain wall electronics. Engineering of precise domain patterns necessitates well founded knowledge of switching kinetics, which can differ significantly from that of undoped LN. In this work, the role of humidity and sample composition in polarization reversal has been investigated under application of the same voltage waveform. Control over domain sizes has been achieved by varying the sample thickness and initial polarizationmore » as well as atmospheric conditions. In addition, local introduction of proton exchanged phases allows for inhibition of domain nucleation or destabilization, which can be utilized to modify domain patterns. Polarization dependent current flow, attributed to charged domain walls and band bending, demonstrates the rectifying ability of Mg:LN in combination with suitable metal electrodes that allow for further tailoring of conductivity.« less

Junction size dependence of ferroelectric properties in e-beam patterned BaTiO{sub 3} ferroelectric tunnel junctions

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

Singh, A. V.; Gupta, A.; Althammer, M.

We investigate the switching characteristics in BaTiO{sub 3}-based ferroelectric tunnel junctions patterned in a capacitive geometry with circular Ru top electrode with diameters ranging from ∼430 to 2300 nm. Two different patterning schemes, viz., lift-off and ion-milling, have been employed to examine the variations in the ferroelectric polarization, switching, and tunnel electro-resistance resulting from differences in the pattering processes. The values of polarization switching field are measured and compared for junctions of different diameter in the samples fabricated using both patterning schemes. We do not find any specific dependence of polarization switching bias on the size of junctions in both samplemore » stacks. The junctions in the ion-milled sample show up to three orders of resistance change by polarization switching and the polarization retention is found to improve with increasing junction diameter. However, similar switching is absent in the lift-off sample, highlighting the effect of patterning scheme on the polarization retention.« less

Electronic devices containing switchably conductive silicon oxides as a switching element and methods for production and use thereof

DOEpatents

Tour, James M.; Yao, Jun; Natelson, Douglas; Zhong, Lin; He, Tao

2015-09-08

In various embodiments, electronic devices containing switchably conductive silicon oxide as a switching element are described herein. The electronic devices are two-terminal devices containing a first electrical contact and a second electrical contact in which at least one of the first electrical contact or the second electrical contact is deposed on a substrate to define a gap region therebetween. A switching layer containing a switchably conductive silicon oxide resides in the gap region between the first electrical contact and the second electrical contact. The electronic devices exhibit hysteretic current versus voltage properties, enabling their use in switching and memory applications. Methods for configuring, operating and constructing the electronic devices are also presented herein.

Electronic devices containing switchably conductive silicon oxides as a switching element and methods for production and use thereof

DOEpatents

Tour, James M; Yao, Jun; Natelson, Douglas; Zhong, Lin; He, Tao

2013-11-26

In various embodiments, electronic devices containing switchably conductive silicon oxide as a switching element are described herein. The electronic devices are two-terminal devices containing a first electrical contact and a second electrical contact in which at least one of the first electrical contact or the second electrical contact is deposed on a substrate to define a gap region therebetween. A switching layer containing a switchably conductive silicon oxide resides in the the gap region between the first electical contact and the second electrical contact. The electronic devices exhibit hysteretic current versus voltage properties, enabling their use in switching and memory applications. Methods for configuring, operating and constructing the electronic devices are also presented herein.

Voltage equaliser for Li-Fe battery

NASA Astrophysics Data System (ADS)

Wu, Jinn-Chang; Jou, Hurng-Liahng; Chuang, Ping-Hao

2013-10-01

In this article, a voltage equaliser is proposed for a battery string with four Li-Fe batteries. The proposed voltage equaliser is developed from a flyback converter, which comprises a transformer, a power electronic switch and a resonant clamped circuit. The transformer contains a primary winding and four secondary windings with the same number of turns connected to each battery. The resonant clamped circuit is for recycling the energy of leakage inductance of the transformer and for performing zero-voltage switching (ZVS) of the power electronic switch. When the power electronic switch is switched on, the energy is stored in the transformer; and when the power electronic switch is switched off, the energy stored in the transformer will automatically charge the battery whose voltage is the lowest. In this way, the voltage of individual batteries in the battery string is balanced. The salient features of the proposed voltage equaliser are that only one switch is used, the energy stored in the leakage inductance of the transformer can be recycled and ZVS is obtained. A prototype is developed and tested to verify the performance of the proposed voltage equaliser. The experimental results show that the proposed voltage equaliser achieves the expected performance.

Piezoelectric-based self-powered electronic adjustable impulse switches

NASA Astrophysics Data System (ADS)

Rastegar, Jahangir; Kwok, Philip

2018-03-01

Novel piezoelectric-based self-powered impulse detecting switches are presented. The switches are designed to detect shock loading events resulting in acceleration or deceleration above prescribed levels and durations. The prescribed acceleration level and duration thresholds are adjustable. They are provided with false trigger protection logic. The impulse switches are provided with electronic and logic circuitry to detect prescribed impulse events and reject events such as high amplitude but short duration shocks, and transportation vibration and similar low amplitude and relatively long duration events. They can be mounted directly onto electronics circuit boards, thereby significantly simplifying the electrical and electronic circuitry, simplifying the assembly process and total cost, significantly reducing the occupied volume, and in some applications eliminating the need for physical wiring to and from the impulse switches. The design of prototypes and testing under realistic conditions are presented.

Texturing Copper To Reduce Secondary Emission Of Electrons

NASA Technical Reports Server (NTRS)

Jensen, Kenneth A.; Curren, Arthur N.; Roman, Robert F.

1995-01-01

Ion-beam process produces clean, deeply textured surfaces on copper substrates with reduced secondary electron emission. In process, molybdenum ring target positioned above and around copper substrate. Target potential repeatedly switched on and off. Switching module described in "High-Voltage MOSFET Switching Circuit" (LEW-15986). Useful for making collector electrodes for traveling-wave-tube and klystron microwave amplifiers, in which secondary emission of electrons undesirable because of reducing efficiency.

Solution-processed flexible NiO resistive random access memory device

NASA Astrophysics Data System (ADS)

Kim, Soo-Jung; Lee, Heon; Hong, Sung-Hoon

2018-04-01

Non-volatile memories (NVMs) using nanocrystals (NCs) as active materials can be applied to soft electronic devices requiring a low-temperature process because NCs do not require a heat treatment process for crystallization. In addition, memory devices can be implemented simply by using a patterning technique using a solution process. In this study, a flexible NiO ReRAM device was fabricated using a simple NC patterning method that controls the capillary force and dewetting of a NiO NC solution at low temperature. The switching behavior of a NiO NC based memory was clearly observed by conductive atomic force microscopy (c-AFM).

New paradigm for task switching strategies while performing multiple tasks: entropy and symbolic dynamics analysis of voluntary patterns.

PubMed

Guastello, Stephen J; Gorin, Hillary; Huschen, Samuel; Peters, Natalie E; Fabisch, Megan; Poston, Kirsten

2012-10-01

It has become well established in laboratory experiments that switching tasks, perhaps due to interruptions at work, incur costs in response time to complete the next task. Conditions are also known that exaggerate or lessen the switching costs. Although switching costs can contribute to fatigue, task switching can also be an adaptive response to fatigue. The present study introduces a new research paradigm for studying the emergence of voluntary task switching regimes, self-organizing processes therein, and the possibly conflicting roles of switching costs and minimum entropy. Fifty-four undergraduates performed 7 different computer-based cognitive tasks producing sets of 49 responses under instructional conditions requiring task quotas or no quotas. The sequences of task choices were analyzed using orbital decomposition to extract pattern types and lengths, which were then classified and compared with regard to Shannon entropy, topological entropy, number of task switches involved, and overall performance. Results indicated that similar but different patterns were generated under the two instructional conditions, and better performance was associated with lower topological entropy. Both entropy metrics were associated with the amount of voluntary task switching. Future research should explore conditions affecting the trade-off between switching costs and entropy, levels of automaticity between task elements, and the role of voluntary switching regimes on fatigue.

Power inverter with optical isolation

DOEpatents

Duncan, Paul G.; Schroeder, John Alan

2005-12-06

An optically isolated power electronic power conversion circuit that includes an input electrical power source, a heat pipe, a power electronic switch or plurality of interconnected power electronic switches, a mechanism for connecting the switch to the input power source, a mechanism for connecting comprising an interconnecting cable and/or bus bar or plurality of interconnecting cables and/or input bus bars, an optically isolated drive circuit connected to the switch, a heat sink assembly upon which the power electronic switch or switches is mounted, an output load, a mechanism for connecting the switch to the output load, the mechanism for connecting including an interconnecting cable and/or bus bar or plurality of interconnecting cables and/or output bus bars, at least one a fiber optic temperature sensor mounted on the heat sink assembly, at least one fiber optic current sensor mounted on the load interconnection cable and/or output bus bar, at least one fiber optic voltage sensor mounted on the load interconnection cable and/or output bus bar, at least one fiber optic current sensor mounted on the input power interconnection cable and/or input bus bar, and at least one fiber optic voltage sensor mounted on the input power interconnection cable and/or input bus bar.

An Approach to Average Modeling and Simulation of Switch-Mode Systems

ERIC Educational Resources Information Center

Abramovitz, A.

2011-01-01

This paper suggests a pedagogical approach to teaching the subject of average modeling of PWM switch-mode power electronics systems through simulation by general-purpose electronic circuit simulators. The paper discusses the derivation of PSPICE/ORCAD-compatible average models of the switch-mode power stages, their software implementation, and…

Switching among graphic patterns is governed by oscillatory coordination dynamics: implications for understanding handwriting

PubMed Central

Zanone, Pier-Giorgio; Athènes, Sylvie

2013-01-01

Revisiting an original idea by Hollerbach (1981), previous work has established that the production of graphic shapes, assumed to be the blueprint for handwriting, is governed by the dynamics of orthogonal non-linear coupled oscillators. Such dynamics determines few stable coordination patterns, giving rise to a limited set of preferred graphic shapes, namely, four lines and four ellipsoids independent of orientation. The present study investigates the rules of switching among such graphic coordination patterns. Seven participants were required to voluntarily switch within twelve pairs of shapes presented on a graphic tablet. In line with previous theoretical and experimental work on bimanual coordination, results corroborated our hypothesis that the relative stability of the produced coordination patterns determines the time needed for switching: the transition to a more stable pattern was shorter, and inversely. Moreover, switching between patterns with the same orientation but different eccentricities was faster than with a change in orientation. Nonetheless, the switching time covaried strictly with the change in relative phase effected by the transition between two shapes, whether this implied a change in eccentricity or in orientation. These findings suggest a new operational definition of what the (motor) units or strokes of handwriting are and shed a novel light on how coarticulation and recruitment of degrees of freedom may occur in graphic skills. They also yield some leads for understanding the acquisition and the neural underpinnings of handwriting. PMID:24069014

Does switching contraceptive from oral to a patch or vaginal ring change the likelihood of timely prescription refill?

PubMed

Law, Amy; Lee, Yi-Chien; Gorritz, Magdaliz; Plouffe, Leo

2014-08-01

This study evaluated contraceptive refill patterns of women insured commercially in the US who switched from oral contraceptives (OCs) to the patch or vaginal ring and assessed if switching contraceptive methods changes refill patterns. Women aged 15-44 with ≥2 patch or ring prescriptions and ≥2 OC prescriptions before the first patch/ring prescription were identified from the MarketScan® Commercial database (1/1/2002-6/30/2011). Refill patterns 1-year pre- and postindex date (first patch/ring prescription) were evaluated, and women were categorized as timely or delayed refillers on OCs and patch/ring. Regression modeling was used to investigate the association between refill patterns and contraceptive methods and switching effects on refill patterns. Of 17,814 women identified, 7901 switched to the patch, and 9913 switched to the ring. Among timely OC refillers, the percentage of timely refills decreased (patch: 95.6% to 79.4%, p<.001; ring: 96.5% to 74.3%, p<.001). However, among delayed OC refillers, the percentage of timely refills improved (patch: 47.9% to 72.2%, p<.001; ring: 50.4% to 64.0%, p<.001) during patch/ring use. Nonetheless, compared to timely OC refillers, women who were delayed OC refillers had 1.68-fold [95% confidence interval (CI): 1.52-1.84, p<.001] and 1.85-fold greater odds (CI: 1.69-2.02, p<.001) of being a delayed refiller while on the patch and ring, respectively. Switching to the patch or ring may improve refill behavior for women who have problems refilling OCs timely; however, the magnitude of the improvement may fail to improve ultimate contraceptive efficacy by simply switching to the patch or ring. The impact on timely refills of switching from OCs to either the patch or ring is complex and varies depending on the pattern of timely refills on OCs. Copyright © 2014 Elsevier Inc. All rights reserved.

Thickness, humidity, and polarization dependent ferroelectric switching and conductivity in Mg doped lithium niobate

DOE PAGES

Neumayer, Sabine M.; Strelcov, Evgheni; Manzo, Michele; ...

2015-12-28

Mg doped lithium niobate (Mg:LN) exhibits several advantages over undoped LN such as resistance to photorefraction, lower coercive fields, and p-type conductivity that is particularly pronounced at domain walls and opens up a range of applications, e.g., in domain wall electronics. Engineering of precise domain patterns necessitates well founded knowledge of switching kinetics, which can differ significantly from that of undoped LN. In this work, the role of humidity and sample composition in polarization reversal has been investigated under application of the same voltage waveform. Control over domain sizes has been achieved by varying the sample thickness and initial polarizationmore » as well as atmospheric conditions. Additionally, local introduction of proton exchanged phases allows for inhibition of domain nucleation or destabilization, which can be utilized to modify domain patterns. In polarization dependent current flow, attributed to charged domain walls and band bending, it the rectifying ability of Mg: LN in combination with suitable metal electrodes that allow for further tailoring of conductivity is demonstrated.« less

Temperature-triggered chemical switching growth of in-plane and vertically stacked graphene-boron nitride heterostructures

PubMed Central

Gao, Teng; Song, Xiuju; Du, Huiwen; Nie, Yufeng; Chen, Yubin; Ji, Qingqing; Sun, Jingyu; Yang, Yanlian; Zhang, Yanfeng; Liu, Zhongfan

2015-01-01

In-plane and vertically stacked heterostructures of graphene and hexagonal boron nitride (h-BN-G and G/h-BN, respectively) are both recent focuses of graphene research. However, targeted synthesis of either heterostructure remains a challenge. Here, via chemical vapour deposition and using benzoic acid precursor, we have achieved the selective growth of h-BN-G and G/h-BN through a temperature-triggered switching reaction. The perfect in-plane h-BN-G is characterized by scanning tunnelling microscopy (STM), showing atomically patched graphene and h-BN with typical zigzag edges. In contrast, the vertical alignment of G/h-BN is confirmed by unique lattice-mismatch-induced moiré patterns in high-resolution STM images, and two sets of aligned selected area electron diffraction spots, both suggesting a van der Waals epitaxial mechanism. The present work demonstrates the chemical designability of growth process for controlled synthesis of graphene and h-BN heterostructures. With practical scalability, high uniformity and quality, our approach will promote the development of graphene-based electronics and optoelectronics. PMID:25869236

Fractal model of polarization switching kinetics in ferroelectrics under nonequilibrium conditions of electron irradiation

NASA Astrophysics Data System (ADS)

Maslovskaya, A. G.; Barabash, T. K.

2018-03-01

The paper presents the results of the fractal and multifractal analysis of polarization switching current in ferroelectrics under electron irradiation, which allows statistical memory effects to be estimated at dynamics of domain structure. The mathematical model of formation of electron beam-induced polarization current in ferroelectrics was suggested taking into account the fractal nature of domain structure dynamics. In order to realize the model the computational scheme was constructed using the numerical solution approximation of fractional differential equation. Evidences of electron beam-induced polarization switching process in ferroelectrics were specified at a variation of control model parameters.

Examining the relationship between comprehension and production processes in code-switched language

PubMed Central

Guzzardo Tamargo, Rosa E.; Valdés Kroff, Jorge R.; Dussias, Paola E.

2016-01-01

We employ code-switching (the alternation of two languages in bilingual communication) to test the hypothesis, derived from experience-based models of processing (e.g., Boland, Tanenhaus, Carlson, & Garnsey, 1989; Gennari & MacDonald, 2009), that bilinguals are sensitive to the combinatorial distributional patterns derived from production and that they use this information to guide processing during the comprehension of code-switched sentences. An analysis of spontaneous bilingual speech confirmed the existence of production asymmetries involving two auxiliary + participle phrases in Spanish–English code-switches. A subsequent eye-tracking study with two groups of bilingual code-switchers examined the consequences of the differences in distributional patterns found in the corpus study for comprehension. Participants’ comprehension costs mirrored the production patterns found in the corpus study. Findings are discussed in terms of the constraints that may be responsible for the distributional patterns in code-switching production and are situated within recent proposals of the links between production and comprehension. PMID:28670049

Examining the relationship between comprehension and production processes in code-switched language.

PubMed

Guzzardo Tamargo, Rosa E; Valdés Kroff, Jorge R; Dussias, Paola E

2016-08-01

We employ code-switching (the alternation of two languages in bilingual communication) to test the hypothesis, derived from experience-based models of processing (e.g., Boland, Tanenhaus, Carlson, & Garnsey, 1989; Gennari & MacDonald, 2009), that bilinguals are sensitive to the combinatorial distributional patterns derived from production and that they use this information to guide processing during the comprehension of code-switched sentences. An analysis of spontaneous bilingual speech confirmed the existence of production asymmetries involving two auxiliary + participle phrases in Spanish-English code-switches. A subsequent eye-tracking study with two groups of bilingual code-switchers examined the consequences of the differences in distributional patterns found in the corpus study for comprehension. Participants' comprehension costs mirrored the production patterns found in the corpus study. Findings are discussed in terms of the constraints that may be responsible for the distributional patterns in code-switching production and are situated within recent proposals of the links between production and comprehension.

Highly flexible and electroforming free resistive switching behavior of tungsten disulfide flakes fabricated through advanced printing technology

NASA Astrophysics Data System (ADS)

Muqeet Rehman, Muhammad; Uddin Siddiqui, Ghayas; Doh, Yang Hoi; Choi, Kyung Hyun

2017-09-01

Tungsten disulfide (WS2) is a transition metal dichalcogenide that differs from other 2D materials such as graphene owing to its distinctive semiconducting nature and tunable band gap. In this study, we have reported the structural, electrical, physical, and mechanical properties of exfoliated WS2 flakes and used them as the functional layer of a rewritable bipolar memory device. We demonstrate this concept by sandwiching few-layered WS2 flakes between two silver (Ag) electrodes on a flexible and transparent PET substrate. The entire device fabrication was carried out through all-printing technology such as reverse offset printing for patterning bottom electrodes, electrohydrodynamic (EHD) atomization for depositing functional thin film and EHD patterning for depositing the top electrode respectively. The memory device was further encapsulated with an atomically thin layer of aluminum oxide (Al2O3), deposited through a spatial atmospheric atomic layer deposition system to protect it against a humid environment. Remarkable resistive switching results were obtained, such as nonvolatile bipolar behavior, a high switching ratio (∼103), a long retention time (∼105 s), high endurance (1500 voltage sweeps), a low operating voltage (∼2 V), low current compliance (50 μA), mechanical robustness (1500 cycles) and unique repeatability at ambient conditions. Ag/WS2/Ag-based memory devices offer a new possibility for integration in flexible electronic devices.

Switch junction sequences in PMS2-deficient mice reveal a microhomology-mediated mechanism of Ig class switch recombination

PubMed Central

Ehrenstein, Michael R.; Rada, Cristina; Jones, Anne-Marie; Milstein, César; Neuberger, Michael S.

2001-01-01

Isotype switching involves a region-specific, nonhomologous recombinational deletion that has been suggested to occur by nonhomologous joining of broken DNA ends. Here, we find increased donor/acceptor homology at switch junctions from PMS2-deficient mice and propose that class switching can occur by microhomology-mediated end-joining. Interestingly, although isotype switching and somatic hypermutation show many parallels, we confirm that PMS2 deficiency has no major effect on the pattern of nucleotide substitutions generated during somatic hypermutation. This finding is in contrast to MSH2 deficiency. With MSH2, the altered pattern of switch recombination and hypermutation suggests parallels in the mechanics of the two processes, whereas the fact that PMS2 deficiency affects only switch recombination may reflect differences in the pathways of break resolution. PMID:11717399

Additive/Subtractive Manufacturing Research and Development in Europe

DTIC Science & Technology

2004-12-01

electronic gates and switches. The idea is to attach a gold nanoparticle to a redox gate (molecule) that undergoes reduction and oxidation reactions...This is used to synthesize mixed metal oxides such as CeO2, Ce:Zr, ZrO2, and Pr:Ce and produce them in nanoparticle form. The fourth project that was...on glass. Laser patterning is followed by heating to diffuse the oxide into the glass. MMSC has used the direct-write of conductors on polymer

Hand preference and skilled hand performance among individuals with successful rightward conversions of the writing hand.

PubMed

Porac, Clare

2009-03-01

Searleman and Porac (2001) studied lateral preference patterns among successfully switched left-hand writers, left-hand writers with no switch pressure history, and left-hand writers who did not switch when pressured. They concluded that left-handers who successfully shift to right-hand writing are following an inherent right-sided lateralisation pattern that they already possess. Searleman and Porac suggested that the neural mechanisms that control lateralisation in the successfully switched individuals are systematically different from those of other groups of left-handers. I examined patterns of skilled and less-skilled hand preference and skilled hand performance in a sample of 394 adults (ages 18-94 years). The sample contained successfully switched left-hand writers, left-handers pressured to shift who remained left-hand writers, left-handers who did not experience shift pressures, and right-handers. Both skilled hand preference and skilled hand performance were shifted towards the right side in successfully switched left-hand writers. This group also displayed mixed patterns of hand preference and skilled hand performance in that they were not as right-sided as "natural" right-handers nor were they as left-sided as the two left-hand writing groups, which did not differ from each other. The experience of being pressured to switch to right-hand writing was not sufficient to shift lateralisation patterns; the pressures must be experienced in the context of an underlying neural control mechanism that is amenable to change as a result of these external influences.

Miniature low voltage beam systems producable by combined lithographies

NASA Astrophysics Data System (ADS)

Koops, Hans W. P.; Munro, Eric; Rouse, John; Kretz, Johannes; Rudolph, Michael; Weber, Markus; Dahm, Gerold

The project of a miniaturized vacuum microelectronic 100 GHz switch is described. It implies the development of a field emission electron gun as well as the investigation of miniaturized lenses and deflectors. Electrostatic elements are designed and developed for this application. Connector pads and wiring pattern are created by conventional electron beam lithography and a lift-off or etching process. Wire and other 3-dimensional structures are grown using electron beam induced deposition. This additive lithography allows to form electrodes and resistors of a preset conductivity. The scanning electron microscope features positioning the structures with nm precision. An unconventional lithography system is used that is capable of controlling the pixel dwell time within a shape with different time functions. With this special function 3-dimensional structures can be generated like free standing square shaped electrodes. The switch is built by computer controlled additive lithography avoiding assembly from parts. Lenses of micrometer dimensions were investigated with numerical electron optics programs computing the 3-dimensional potential and field distribution. From the extracted axial field distribution the electron optic characteristic parameters, like focal length, chromatic and spherical aberration, were calculated for various lens excitations. The analysis reveals that miniaturized optics for low energy electrons, as low as 30 eV, are diffraction limited. For a lens with 2 μm focal length, a chromatic aberration disc of 1 nm contributes to 12 nm diffraction disc. The spherical aberration blurs the probe by 0.02 nm, assuming an aperture of 0.01 rad. Employing hydrogen ions at 100 V, a probe diameter of 0.3 nm generated by chromatic aberration is possible. Miniaturized electron optical probe forming systems and imaging systems can be constructed with those lenses. Its application as lithography systems with massive parallel beams can be forseen.

Moving receive beam method and apparatus for synthetic aperture radar

DOEpatents

Kare, Jordin T.

2001-01-01

A method and apparatus for improving the performance of Synthetic Aperture Radar (SAR) systems by reducing the effect of "edge losses" associated with nonuniform receiver antenna gain. By moving the receiver antenna pattern in synchrony with the apparent motion of the transmitted pulse along the ground, the maximum available receiver antenna gain can be used at all times. Also, the receiver antenna gain for range-ambiguous return signals may be reduced, in some cases, by a large factor. The beam motion can be implemented by real-time adjustment of phase shifters in an electronically-steered phased-array antenna or by electronic switching of feed horns in a reflector antenna system.

Electronically-Scanned Pressure Sensors

NASA Technical Reports Server (NTRS)

Coe, C. F.; Parra, G. T.; Kauffman, R. C.

1984-01-01

Sensors not pneumatically switched. Electronic pressure-transducer scanning system constructed in modular form. Pressure transducer modules and analog to digital converter module small enough to fit within cavities of average-sized wind-tunnel models. All switching done electronically. Temperature controlled environment maintained within sensor modules so accuracy maintained while ambient temperature varies.

Electronic Computer and Switching Systems Specialist (AFSC 30554).

ERIC Educational Resources Information Center

Air Univ., Gunter AFS, Ala. Extension Course Inst.

This course is intended to train Air Force personnel to become electronic computer and switching systems specialists. One part of the course consists of a three-volume career development course. Topics are maintenance orientation (15 hours), electronic principles and digital techniques (87 hours), and systems maintenance (51 hours). Each volume…

An optical switch

DOEpatents

Christophorou, L.G.; Hunter, S.R.

1987-04-30

The invention is a gas mixture for a diffuse discharge switch having an electron attaching gas wherein electron attachment is brought about by indirect excitation of molecules to long live states by exposure to laser light. 3 figs.

Solid-state active switch matrix for high energy, moderate power battery systems

DOEpatents

Deal, Larry; Paris, Peter; Ye, Changqing

2016-06-07

A battery management system employs electronic switches and capacitors. No traditional cell-balancing resistors are used. The BMS electronically switches individual cells into and out of a module of cells in order to use the maximum amount of energy available in each cell and to completely charge and discharge each cell without overcharging or under-discharging.

47 CFR 32.5999 - General.

Code of Federal Regulations, 2014 CFR

2014-10-01

... switching expense 6210 Non-digital switching expense 6211 Digital electronic switching expense 6212... Circuit equipment expense 6232 Information origination/termination expense 6310 Station apparatus expense...

47 CFR 32.5999 - General.

Code of Federal Regulations, 2012 CFR

2012-10-01

... switching expense 6210 Non-digital switching expense 6211 Digital electronic switching expense 6212... Circuit equipment expense 6232 Information origination/termination expense 6310 Station apparatus expense...

47 CFR 32.5999 - General.

Code of Federal Regulations, 2013 CFR

2013-10-01

... switching expense 6210 Non-digital switching expense 6211 Digital electronic switching expense 6212... Circuit equipment expense 6232 Information origination/termination expense 6310 Station apparatus expense...

Nonlocal Electron Coherence in MoS2 Flakes Correlated through Spatial Self Phase Modulation

NASA Astrophysics Data System (ADS)

Wu, Yanling; Wu, Qiong; Sun, Fei; Tian, Yichao; Zuo, Xu; Meng, Sheng; Zhao, Jimin

2015-03-01

Electron coherence among different flake domains of MoS2 has been generated using ultrafast or continuous wave laser beams. Such electron coherence generates characteristic far-field diffraction patterns through a purely coherent nonlinear optical effect--spatial self-phase modulation (SSPM). A wind-chime model is developed to describe the establishment of the electron coherence through correlating the photo-excited electrons among different flakes using coherent light. Owing to its finite gap band structure, we find different mechanisms, including two-photon processes, might be responsible for the SSPM in MoS2 [with a large nonlinear dielectric susceptibility χ (3) = 1.6 × 10-9 e.s.u. (SI: 2.23 × 10-17 m2/V2) per layer]. Finally, we realized all optical switching based on SSPM, demonstrating that the electron coherence generation we report here is a ubiquitous property of layered quantum materials, by which novel optical applications are accessible. National Natural Science Foundation of China (11274372).

LED lamp power management system and method

DOEpatents

Gaines, James; Clauberg, Bernd; Van Erp, Josephus A. M.

2013-03-19

An LED lamp power management system and method including an LED lamp having an LED controller 58; a plurality of LED channels 60 operably connected to the LED controller 58, each of the plurality of LED channels 60 having a channel switch 62 in series with at least one shunted LED circuit 83, the shunted LED circuit 83 having a shunt switch 68 in parallel with an LED source 80. The LED controller 58 reduces power loss in one of the channel switch 62 and the shunt switch 68 when LED lamp electronics power loss (P.sub.loss) exceeds an LED lamp electronics power loss limit (P.sub.lim); and each of the channel switches 62 receives a channel switch control signal 63 from the LED controller 58 and each of the shunt switches 68 receives a shunt switch control signal 69 from the LED controller 58.

Study of switching behavior of exchange-coupled nanomagnets by transverse magnetization metrology

NASA Astrophysics Data System (ADS)

Dey, Himadri S.; Csaba, Gyorgy; Bernstein, Gary H.; Porod, Wolfgang

2017-05-01

We investigate the static switching modes of nanomagnets patterned from antiferromagnetically exchange-coupled magnetic multilayers, and compare them to nanomagnets having only dipole coupling between the ferromagnetic layers. Vibrating sample magnetometry experiments, supported by micromagnetic simulations, reveal two distinct switching mechanisms between the exchange-coupled and only dipole-coupled nanomagnets. The exchange-coupled nanomagnets exhibit gradual switching of the layers, dictated by the strong antiferromagnetic exchange coupling present between the layers. However, the layers of the only dipole-coupled nanomagnets show abrupt nucleation/growth type switching. A comprehensive understanding of the switching modes of such layered and patterned systems can add new insight into the reversal mechanisms of similar systems employed for spintronic and magneto-logic device applications.

Resolution Improvement and Pattern Generator Development for theMaskless Micro-Ion-Beam Reduction Lithography System

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

Jiang, Ximan

The shrinking of IC devices has followed the Moore's Law for over three decades, which states that the density of transistors on integrated circuits will double about every two years. This great achievement is obtained via continuous advance in lithography technology. With the adoption of complicated resolution enhancement technologies, such as the phase shifting mask (PSM), the optical proximity correction (OPC), optical lithography with wavelength of 193 nm has enabled 45 nm printing by immersion method. However, this achievement comes together with the skyrocketing cost of masks, which makes the production of low volume application-specific IC (ASIC) impractical. In ordermore » to provide an economical lithography approach for low to medium volume advanced IC fabrication, a maskless ion beam lithography method, called Maskless Micro-ion-beam Reduction Lithography (MMRL), has been developed in the Lawrence Berkeley National Laboratory. The development of the prototype MMRL system has been described by Dr. Vinh Van Ngo in his Ph.D. thesis. But the resolution realized on the prototype MMRL system was far from the design expectation. In order to improve the resolution of the MMRL system, the ion optical system has been investigated. By integrating a field-free limiting aperture into the optical column, reducing the electromagnetic interference and cleaning the RF plasma, the resolution has been improved to around 50 nm. Computational analysis indicates that the MMRL system can be operated with an exposure field size of 0.25 mm and a beam half angle of 1.0 mrad on the wafer plane. Ion-ion interactions have been studied with a two-particle physics model. The results are in excellent agreement with those published by the other research groups. The charge-interaction analysis of MMRL shows that the ion-ion interactions must be reduced in order to obtain a throughput higher than 10 wafers per hour on 300-mm wafers. In addition, two different maskless lithography strategies have been studied. The dependence of the throughput with the exposure field size and the speed of the mechanical stage has been investigated. In order to perform maskless lithography, different micro-fabricated pattern generators have been developed for the MMRL system. Ion beamlet switching has been successfully demonstrated on the MMRL system. A positive bias voltage around 10 volts is sufficient to switch off the ion current on the micro-fabricated pattern generators. Some unexpected problems, such as the high-energy secondary electron radiations, have been discovered during the experimental investigation. Thermal and structural analysis indicates that the aperture displacement error induced by thermal expansion can satisfy the 3δ CD requirement for lithography nodes down to 25 nm. The cross-talking effect near the surface and inside the apertures of the pattern generator has been simulated in a 3-D ray-tracing code. New pattern generator design has been proposed to reduce the cross-talking effect. In order to eliminate the surface charging effect caused by the secondary electrons, a new beam-switching scheme in which the switching electrodes are immersed in the plasma has been demonstrated on a mechanically fabricated pattern generator.« less

Interchangeability of biosimilar and biological reference product: updated regulatory positions and pre- and post-marketing evidence.

PubMed

Trifirò, Gianluca; Marcianò, Ilaria; Ingrasciotta, Ylenia

2018-03-01

Since 2006, biosimilars have been available in several countries worldwide, thus allowing for potential savings in pharmaceutical expenditure. However, there have been numerous debates about the interchangeability of biosimilars and reference products based on concerns of immunogenicity by switching between biological products, which may cause lack of effect and toxicity. Areas covered: The authors provide the reader with an overview of the different positions of regulatory authorities on the interchangeability and automatic substitution of biosimilars and reference products. Presently, the FDA allows automatic substitution without prescriber intervention if the biosimilar is interchangeable with reference products, while the European Medicines Agency delegate to each single EU member state. Expert opinion: Different approaches in defining interchangeability and automatic substitution call for harmonization to increase confidence of healthcare professionals and patients about the clinical impact of switching. Networks of electronic healthcare records and administrative databases, potentially linkable to clinical charts and registries may rapidly assess frequency and benefit-risk profile of different switching patterns in routine care at different levels, thus integrating and strengthening pre-marketing evidence.

Fast superconducting magnetic field switch

DOEpatents

Goren, Yehuda; Mahale, Narayan K.

1996-01-01

The superconducting magnetic switch or fast kicker magnet is employed with electron stream or a bunch of electrons to rapidly change the direction of flow of the electron stream or bunch of electrons. The apparatus employs a beam tube which is coated with a film of superconducting material. The tube is cooled to a temperature below the superconducting transition temperature and is subjected to a constant magnetic field which is produced by an external dc magnet. The magnetic field produced by the dc magnet is less than the critical field for the superconducting material, thus, creating a Meissner Effect condition. A controllable fast electromagnet is used to provide a magnetic field which supplements that of the dc magnet so that when the fast magnet is energized the combined magnetic field is now greater that the critical field and the superconducting material returns to its normal state allowing the magnetic field to penetrate the tube. This produces an internal field which effects the direction of motion and of the electron stream or electron bunch. The switch can also operate as a switching mechanism for charged particles.

Fast superconducting magnetic field switch

DOEpatents

Goren, Y.; Mahale, N.K.

1996-08-06

The superconducting magnetic switch or fast kicker magnet is employed with electron stream or a bunch of electrons to rapidly change the direction of flow of the electron stream or bunch of electrons. The apparatus employs a beam tube which is coated with a film of superconducting material. The tube is cooled to a temperature below the superconducting transition temperature and is subjected to a constant magnetic field which is produced by an external dc magnet. The magnetic field produced by the dc magnet is less than the critical field for the superconducting material, thus, creating a Meissner Effect condition. A controllable fast electromagnet is used to provide a magnetic field which supplements that of the dc magnet so that when the fast magnet is energized the combined magnetic field is now greater that the critical field and the superconducting material returns to its normal state allowing the magnetic field to penetrate the tube. This produces an internal field which effects the direction of motion and of the electron stream or electron bunch. The switch can also operate as a switching mechanism for charged particles. 6 figs.

Valley switch in a graphene superlattice due to pseudo-Andreev reflection

NASA Astrophysics Data System (ADS)

Beenakker, C. W. J.; Gnezdilov, N. V.; Dresselhaus, E.; Ostroukh, V. P.; Herasymenko, Y.; Adagideli, I.; Tworzydło, J.

2018-06-01

Dirac electrons in graphene have a valley degree of freedom that is being explored as a carrier of information. In that context of "valleytronics" one seeks to coherently manipulate the valley index. Here, we show that reflection from a superlattice potential can provide a valley switch: Electrons approaching a pristine-graphene-superlattice-graphene interface near normal incidence are reflected in the opposite valley. We identify the topological origin of this valley switch, by mapping the problem onto that of Andreev reflection from a topological superconductor, with the electron-hole degree of freedom playing the role of the valley index. The valley switch is ideal at a symmetry point of the superlattice potential, but remains close to 100% in a broad parameter range.

Realization of the Switching Mechanism in Resistance Random Access Memory™ Devices: Structural and Electronic Properties Affecting Electron Conductivity in a Hafnium Oxide-Electrode System Through First-Principles Calculations

NASA Astrophysics Data System (ADS)

Aspera, Susan Meñez; Kasai, Hideaki; Kishi, Hirofumi; Awaya, Nobuyoshi; Ohnishi, Shigeo; Tamai, Yukio

2013-01-01

The resistance random access memory (RRAM™) device, with its electrically induced nanoscale resistive switching capacity, has attracted considerable attention as a future nonvolatile memory device. Here, we propose a mechanism of switching based on an oxygen vacancy migration-driven change in the electronic properties of the transition-metal oxide film stimulated by set pulse voltages. We used density functional theory-based calculations to account for the effect of oxygen vacancies and their migration on the electronic properties of HfO2 and Ta/HfO2 systems, thereby providing a complete explanation of the RRAM™ switching mechanism. Furthermore, computational results on the activation energy barrier for oxygen vacancy migration were found to be consistent with the set and reset pulse voltage obtained from experiments. Understanding this mechanism will be beneficial to effectively realizing the materials design in these devices.

Organization of the channel-switching process in parallel computer systems based on a matrix optical switch

NASA Technical Reports Server (NTRS)

Golomidov, Y. V.; Li, S. K.; Popov, S. A.; Smolov, V. B.

1986-01-01

After a classification and analysis of electronic and optoelectronic switching devices, the design principles and structure of a matrix optical switch is described. The switching and pair-exclusion operations in this type of switch are examined, and a method for the optical switching of communication channels is elaborated. Finally, attention is given to the structural organization of a parallel computer system with a matrix optical switch.

Stable individual characteristics in the perception of multiple embedded patterns in multistable auditory stimuli

PubMed Central

Denham, Susan; Bõhm, Tamás M.; Bendixen, Alexandra; Szalárdy, Orsolya; Kocsis, Zsuzsanna; Mill, Robert; Winkler, István

2014-01-01

The ability of the auditory system to parse complex scenes into component objects in order to extract information from the environment is very robust, yet the processing principles underlying this ability are still not well understood. This study was designed to investigate the proposal that the auditory system constructs multiple interpretations of the acoustic scene in parallel, based on the finding that when listening to a long repetitive sequence listeners report switching between different perceptual organizations. Using the “ABA-” auditory streaming paradigm we trained listeners until they could reliably recognize all possible embedded patterns of length four which could in principle be extracted from the sequence, and in a series of test sessions investigated their spontaneous reports of those patterns. With the training allowing them to identify and mark a wider variety of possible patterns, participants spontaneously reported many more patterns than the ones traditionally assumed (Integrated vs. Segregated). Despite receiving consistent training and despite the apparent randomness of perceptual switching, we found individual switching patterns were idiosyncratic; i.e., the perceptual switching patterns of each participant were more similar to their own switching patterns in different sessions than to those of other participants. These individual differences were found to be preserved even between test sessions held a year after the initial experiment. Our results support the idea that the auditory system attempts to extract an exhaustive set of embedded patterns which can be used to generate expectations of future events and which by competing for dominance give rise to (changing) perceptual awareness, with the characteristics of pattern discovery and perceptual competition having a strong idiosyncratic component. Perceptual multistability thus provides a means for characterizing both general mechanisms and individual differences in human perception. PMID:24616656

Stable individual characteristics in the perception of multiple embedded patterns in multistable auditory stimuli.

PubMed

Denham, Susan; Bõhm, Tamás M; Bendixen, Alexandra; Szalárdy, Orsolya; Kocsis, Zsuzsanna; Mill, Robert; Winkler, István

2014-01-01

The ability of the auditory system to parse complex scenes into component objects in order to extract information from the environment is very robust, yet the processing principles underlying this ability are still not well understood. This study was designed to investigate the proposal that the auditory system constructs multiple interpretations of the acoustic scene in parallel, based on the finding that when listening to a long repetitive sequence listeners report switching between different perceptual organizations. Using the "ABA-" auditory streaming paradigm we trained listeners until they could reliably recognize all possible embedded patterns of length four which could in principle be extracted from the sequence, and in a series of test sessions investigated their spontaneous reports of those patterns. With the training allowing them to identify and mark a wider variety of possible patterns, participants spontaneously reported many more patterns than the ones traditionally assumed (Integrated vs. Segregated). Despite receiving consistent training and despite the apparent randomness of perceptual switching, we found individual switching patterns were idiosyncratic; i.e., the perceptual switching patterns of each participant were more similar to their own switching patterns in different sessions than to those of other participants. These individual differences were found to be preserved even between test sessions held a year after the initial experiment. Our results support the idea that the auditory system attempts to extract an exhaustive set of embedded patterns which can be used to generate expectations of future events and which by competing for dominance give rise to (changing) perceptual awareness, with the characteristics of pattern discovery and perceptual competition having a strong idiosyncratic component. Perceptual multistability thus provides a means for characterizing both general mechanisms and individual differences in human perception.

Organic Materials For Optical Switching

NASA Technical Reports Server (NTRS)

Cardelino, Beatriz H.

1993-01-01

Equations predict properties of candidate materials. Report presents results of theoretical study of nonlinear optical properties of organic materials. Such materials used in optical switching devices for computers and telecommunications, replacing electronic switches. Optical switching potentially offers extremely high information throughout in compact hardware.

Interplay of hot electrons from localized and propagating plasmons.

PubMed

Hoang, Chung V; Hayashi, Koki; Ito, Yasuo; Gorai, Naoki; Allison, Giles; Shi, Xu; Sun, Quan; Cheng, Zhenzhou; Ueno, Kosei; Goda, Keisuke; Misawa, Hiroaki

2017-10-03

Plasmon-induced hot-electron generation has recently received considerable interest and has been studied to develop novel applications in optoelectronics, photovoltaics and green chemistry. Such hot electrons are typically generated from either localized plasmons in metal nanoparticles or propagating plasmons in patterned metal nanostructures. Here we simultaneously generate these heterogeneous plasmon-induced hot electrons and exploit their cooperative interplay in a single metal-semiconductor device to demonstrate, as an example, wavelength-controlled polarity-switchable photoconductivity. Specifically, the dual-plasmon device produces a net photocurrent whose polarity is determined by the balance in population and directionality between the hot electrons from localized and propagating plasmons. The current responsivity and polarity-switching wavelength of the device can be varied over the entire visible spectrum by tailoring the hot-electron interplay in various ways. This phenomenon may provide flexibility to manipulate the electrical output from light-matter interaction and offer opportunities for biosensors, long-distance communications, and photoconversion applications.Plasmon-induced hot electrons have potential applications spanning photodetection and photocatalysis. Here, Hoang et al. study the interplay between hot electrons generated by localized and propagating plasmons, and demonstrate wavelength-controlled polarity-switchable photoconductivity.

Tunneling explains efficient electron transport via protein junctions.

PubMed

Fereiro, Jerry A; Yu, Xi; Pecht, Israel; Sheves, Mordechai; Cuevas, Juan Carlos; Cahen, David

2018-05-15

Metalloproteins, proteins containing a transition metal ion cofactor, are electron transfer agents that perform key functions in cells. Inspired by this fact, electron transport across these proteins has been widely studied in solid-state settings, triggering the interest in examining potential use of proteins as building blocks in bioelectronic devices. Here, we report results of low-temperature (10 K) electron transport measurements via monolayer junctions based on the blue copper protein azurin (Az), which strongly suggest quantum tunneling of electrons as the dominant charge transport mechanism. Specifically, we show that, weakening the protein-electrode coupling by introducing a spacer, one can switch the electron transport from off-resonant to resonant tunneling. This is a consequence of reducing the electrode's perturbation of the Cu(II)-localized electronic state, a pattern that has not been observed before in protein-based junctions. Moreover, we identify vibronic features of the Cu(II) coordination sphere in transport characteristics that show directly the active role of the metal ion in resonance tunneling. Our results illustrate how quantum mechanical effects may dominate electron transport via protein-based junctions.

Zero-static power radio-frequency switches based on MoS2 atomristors.

PubMed

Kim, Myungsoo; Ge, Ruijing; Wu, Xiaohan; Lan, Xing; Tice, Jesse; Lee, Jack C; Akinwande, Deji

2018-06-28

Recently, non-volatile resistance switching or memristor (equivalently, atomristor in atomic layers) effect was discovered in transitional metal dichalcogenides (TMD) vertical devices. Owing to the monolayer-thin transport and high crystalline quality, ON-state resistances below 10 Ω are achievable, making MoS 2 atomristors suitable as energy-efficient radio-frequency (RF) switches. MoS 2 RF switches afford zero-hold voltage, hence, zero-static power dissipation, overcoming the limitation of transistor and mechanical switches. Furthermore, MoS 2 switches are fully electronic and can be integrated on arbitrary substrates unlike phase-change RF switches. High-frequency results reveal that a key figure of merit, the cutoff frequency (f c ), is about 10 THz for sub-μm 2 switches with favorable scaling that can afford f c above 100 THz for nanoscale devices, exceeding the performance of contemporary switches that suffer from an area-invariant scaling. These results indicate a new electronic application of TMDs as non-volatile switches for communication platforms, including mobile systems, low-power internet-of-things, and THz beam steering.

Smoothing tautologies, hidden dynamics, and sigmoid asymptotics for piecewise smooth systems

NASA Astrophysics Data System (ADS)

Jeffrey, Mike R.

2015-10-01

Switches in real systems take many forms, such as impacts, electronic relays, mitosis, and the implementation of decisions or control strategies. To understand what is lost, and what can be retained, when we model a switch as an instantaneous event, requires a consideration of so-called hidden terms. These are asymptotically vanishing outside the switch, but can be encoded in the form of nonlinear switching terms. A general expression for the switch can be developed in the form of a series of sigmoid functions. We review the key steps in extending Filippov's method of sliding modes to such systems. We show how even slight nonlinear effects can hugely alter the behaviour of an electronic control circuit, and lead to "hidden" attractors inside the switching surface.

Smoothing tautologies, hidden dynamics, and sigmoid asymptotics for piecewise smooth systems.

PubMed

Jeffrey, Mike R

2015-10-01

Switches in real systems take many forms, such as impacts, electronic relays, mitosis, and the implementation of decisions or control strategies. To understand what is lost, and what can be retained, when we model a switch as an instantaneous event, requires a consideration of so-called hidden terms. These are asymptotically vanishing outside the switch, but can be encoded in the form of nonlinear switching terms. A general expression for the switch can be developed in the form of a series of sigmoid functions. We review the key steps in extending Filippov's method of sliding modes to such systems. We show how even slight nonlinear effects can hugely alter the behaviour of an electronic control circuit, and lead to "hidden" attractors inside the switching surface.

Smoothing tautologies, hidden dynamics, and sigmoid asymptotics for piecewise smooth systems

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

Jeffrey, Mike R., E-mail: mike.jeffrey@bristol.ac.uk

2015-10-15

Switches in real systems take many forms, such as impacts, electronic relays, mitosis, and the implementation of decisions or control strategies. To understand what is lost, and what can be retained, when we model a switch as an instantaneous event, requires a consideration of so-called hidden terms. These are asymptotically vanishing outside the switch, but can be encoded in the form of nonlinear switching terms. A general expression for the switch can be developed in the form of a series of sigmoid functions. We review the key steps in extending Filippov's method of sliding modes to such systems. We showmore » how even slight nonlinear effects can hugely alter the behaviour of an electronic control circuit, and lead to “hidden” attractors inside the switching surface.« less

Development of Simulated Disturbing Source for Isolation Switch

NASA Astrophysics Data System (ADS)

Cheng, Lin; Liu, Xiang; Deng, Xiaoping; Pan, Zhezhe; Zhou, Hang; Zhu, Yong

2018-01-01

In order to simulate the substation in the actual scene of the harsh electromagnetic environment, and then research on electromagnetic compatibility testing of electronic instrument transformer, On the basis of the original isolation switch as a harassment source of the electronic instrument transformer electromagnetic compatibility test system, an isolated switch simulation source system was developed, to promote the standardization of the original test. In this paper, the circuit breaker is used to control the opening and closing of the gap arc to simulate the operating of isolating switch, and the isolation switch simulation harassment source system is designed accordingly. Comparison with the actual test results of the isolating switch, it is proved that the system can meet the test requirements, and the simulation harassment source system has good stability and high reliability.

Safety Assessment of TACOM’s Crew Station/Turret Motion Base Simulator

DTIC Science & Technology

1992-04-01

mode. The power ON switch is interlocked with the system hydraulic pressure switch so that the electronics can not be turned off while the system...analog) "o Oil Temperature Transducer (analog) "o Facility Pressure Switch o Pressure Critical Switch "o Six Supply Solenoid Valves "O Three Accumulator...Relief Solenoid Valves o Return Pressure Switch o Return Valve Switch o Six Filter Clogged Switches (one per filter) The Facility Pressure switch detects

A low-latency optical switch architecture using integrated μm SOI-based contention resolution and switching

NASA Astrophysics Data System (ADS)

Mourgias-Alexandris, G.; Moralis-Pegios, M.; Terzenidis, N.; Cherchi, M.; Harjanne, M.; Aalto, T.; Vyrsokinos, K.; Pleros, N.

2018-02-01

The urgent need for high-bandwidth and high-port connectivity in Data Centers has boosted the deployment of optoelectronic packet switches towards bringing high data-rate optics closer to the ASIC, realizing optical transceiver functions directly at the ASIC package for high-rate, low-energy and low-latency interconnects. Even though optics can offer a broad range of low-energy integrated switch fabrics for replacing electronic switches and seamlessly interface with the optical I/Os, the use of energy- and latency-consuming electronic SerDes continues to be a necessity, mainly dictated by the absence of integrated and reliable optical buffering solutions. SerDes undertakes the role of optimally synergizing the lower-speed electronic buffers with the incoming and outgoing optical streams, suggesting that a SerDes-released chip-scale optical switch fabric can be only realized in case all necessary functions including contention resolution and switching can be implemented on a common photonic integration platform. In this paper, we demonstrate experimentally a hybrid Broadcast-and-Select (BS) / wavelength routed optical switch that performs both the optical buffering and switching functions with μm-scale Silicon-integrated building blocks. Optical buffering is carried out in a silicon-integrated variable delay line bank with a record-high on-chip delay/footprint efficiency of 2.6ns/mm2 and up to 17.2 nsec delay capability, while switching is executed via a BS design and a silicon-integrated echelle grating, assisted by SOA-MZI wavelength conversion stages and controlled by a FPGA header processing module. The switch has been experimentally validated in a 3x3 arrangement with 10Gb/s NRZ optical data packets, demonstrating error-free switching operation with a power penalty of <5dB.

Explosive-driven, high speed, arcless switch

DOEpatents

Skogmo, P.J.; Tucker, T.J.

1986-05-02

An explosive-actuated, fast-acting arcless switch contains a highly conductive foil to carry high currents positioned adjacent a dielectric surface within a casing. At one side of the foil opposite the dielectric surface is an explosive which, when detonated, drives the conductive foil against the dielectric surface. A pattern of grooves in the dielectric surface ruptures the foil to establish a rupture path having a pattern corresponding to the pattern of the grooves. The impedance of the ruptured foil is greater than that of the original foil to divert high current to a load. Planar and cylindrical embodiments of the switch are disclosed.

Explosive-driven, high speed, arcless switch

DOEpatents

Skogmo, Phillip J.; Tucker, Tillman J.

1987-01-01

An explosive-actuated, fast-acting arcless switch contains a highly conductive foil to carry high currents positioned adjacent a dielectric surface within a casing. At one side of the foil opposite the dielectric surface is an explosive which, when detonated, drives the conductive foil against the dielectric surface. A pattern of grooves in the dielectric surface ruptures the foil to establish a rupture path having a pattern corresponding to the pattern of the grooves. The impedance of the ruptured foil is greater than that of the original foil to divert high current to a load. Planar and cylindrical embodiments of the switch are disclosed.

EDITORIAL: Molecular switches at surfaces Molecular switches at surfaces

NASA Astrophysics Data System (ADS)

Weinelt, Martin; von Oppen, Felix

2012-10-01

In nature, molecules exploit interaction with their environment to realize complex functionalities on the nanometer length scale. Physical, chemical and/or biological specificity is frequently achieved by the switching of molecules between microscopically different states. Paradigmatic examples are the energy production in proton pumps of bacteria or the signal conversion in human vision, which rely on switching molecules between different configurations or conformations by external stimuli. The remarkable reproducibility and unparalleled fatigue resistance of these natural processes makes it highly desirable to emulate nature and develop artificial systems with molecular functionalities. A promising avenue towards this goal is to anchor the molecular switches at surfaces, offering new pathways to control their functional properties, to apply electrical contacts, or to integrate switches into larger systems. Anchoring at surfaces allows one to access the full range from individual molecular switches to self-assembled monolayers of well-defined geometry and to customize the coupling between molecules and substrate or between adsorbed molecules. Progress in this field requires both synthesis and preparation of appropriate molecular systems and control over suitable external stimuli, such as light, heat, or electrical currents. To optimize switching and generate function, it is essential to unravel the geometric structure, the electronic properties and the dynamic interactions of the molecular switches on surfaces. This special section, Molecular Switches at Surfaces, collects 17 contributions describing different aspects of this research field. They analyze elementary processes, both in single molecules and in ensembles of molecules, which involve molecular switching and concomitant changes of optical, electronic, or magnetic properties. Two topical reviews summarize the current status, including both challenges and achievements in the field of molecular switches on metal surfaces, focusing on electronic and vibrational spectroscopy in one case and scanning tunneling microscopy studies in the other. Original research articles describe results in many aspects of the field, including: Self-assembly, self-organization, and controlled growth of molecular layers on various substrates. Highly-ordered arrays provide model systems with extraordinary structural properties, allowing one to adjust interactions between molecules and between molecule and substrate, and can be robustly prepared from solution, an essential prerequisite for applications. Conformational or electronic switching of molecules adsorbed at metal and semiconductor surfaces. These studies highlight the elementary processes governing molecular switching at surfaces as well as the wide range of possible stimuli. Carbon-based substrates such as graphene or carbon nanotubes. These substrates are attractive due to their effective two-dimensionality which implies that switching of adsorbed molecules can effect a significant back-action on the substrate. Mechanisms of conformational switching. Several contributions study the role of electron-vibron coupling and heating in current-induced conformational switching. We hope that the collection of articles presented here will stimulate and encourage researchers in surface physics and interfacial chemistry to contribute to the still emerging field of molecular switches at surfaces. We wish to acknowledge the support and input from many colleagues in preparing this special section. A significant part of this work has been conducted in the framework of the Sonderforschungsbereich 658 Elementary Processes in Molecular Switches at Surfaces of the Deutsche Forschungsgemeinschaft, to which we are grateful for financial support. Molecular surfaces at switches contents Molecular switches at surfacesMartin Weinelt and Felix von Oppen Optically and thermally induced molecular switching processes at metal surfacesPetra Tegeder Effects of electron-vibration coupling in transport through single moleculesKatharina J Franke and Jose Ignacio Pascual Vibrational heating in single-molecule switches: an energy-dependent density-of-states approachT Brumme, R Gutierrez and G Cuniberti Reversible switching of single tin phthalocyanine molecules on the InAs(111)A surfaceC Nacci, K Kanisawa and S Fölsch Tuning the interaction between carbon nanotubes and dipole switches: the influence of the change of the nanotube-spiropyran distanceP Bluemmel, A Setaro, C Maity, S Hecht and S Reich Carbon nanotubes as substrates for molecular spiropyran-based switchesE Malic, A Setaro, P Bluemmel, Carlos F Sanz-Navarro, Pablo Ordejón, S Reich and A Knorr Ultrafast dynamics of dithienylethenes differently linked to the surface of TiO2 nanoparticlesLars Dworak, Marc Zastrow, Gehad Zeyat, Karola Rück-Braun and Josef Wachtveitl Switching the electronic properties of Co-octaethylporphyrin molecules on oxygen-covered Ni films by NO adsorptionC F Hermanns, M Bernien, A Krüger, J Miguel and W Kuch STM-switching of organic molecules on semiconductor surfaces: an above threshold density matrix model for 1,5 cyclooctadiene on Si(100)K Zenichowski, Ch Nacci, S Fölsch, J Dokić, T Klamroth and P Saalfrank A switch based on self-assembled thymineFatih Kalkan, Michael Mehlhorn and Karina Morgenstern The growth and electronic structure of azobenzene-based functional molecules on layered crystalsJ Iwicki, E Ludwig, J Buck, M Kalläne, F Köhler, R Herges, L Kipp and K Rossnagel Voltage-dependent conductance states of a single-molecule junctionY F Wang, N Néel, J Kröger, H Vázquez, M Brandbyge, B Wang and R Berndt Molecules with multiple switching units on a Au(111) surface: self-organization and single-molecule manipulationJohannes Mielke, Sofia Selvanathan, Maike Peters, Jutta Schwarz, Stefan Hecht and Leonhard Grill Preparing and regulating a bi-stable molecular switch by atomic manipulationS Sakulsermsuk, R E Palmer and P A Sloan Mixed self-assembled monolayers of azobenzene photoswitches with trifluoromethyl and cyano end groupsDaniel Brete, Daniel Przyrembel, Christian Eickhoff, Robert Carley, Wolfgang Freyer, Karsten Reuter, Cornelius Gahl and Martin Weinelt Reversible electron-induced cis-trans isomerization mediated by intermolecular interactionsCh Lotze, Y Luo, M Corso, K J Franke, R Haag and J I Pascual Transport properties of graphene functionalized with molecular switchesNiels Bode, Eros Mariani and Felix von Oppen

Characterization of a unique [FeS] cluster in the electron transfer chain of the oxygen tolerant [NiFe] hydrogenase from Aquifex aeolicus.

PubMed

Pandelia, Maria-Eirini; Nitschke, Wolfgang; Infossi, Pascale; Giudici-Orticoni, Marie-Thérèse; Bill, Eckhard; Lubitz, Wolfgang

2011-04-12

Iron-sulfur clusters are versatile electron transfer cofactors, ubiquitous in metalloenzymes such as hydrogenases. In the oxygen-tolerant Hydrogenase I from Aquifex aeolicus such electron "wires" form a relay to a diheme cytb, an integral part of a respiration pathway for the reduction of O(2) to water. Amino acid sequence comparison with oxygen-sensitive hydrogenases showed conserved binding motifs for three iron-sulfur clusters, the nature and properties of which were unknown so far. Electron paramagnetic resonance spectra exhibited complex signals that disclose interesting features and spin-coupling patterns; by redox titrations three iron-sulfur clusters were identified in their usual redox states, a [3Fe4S] and two [4Fe4S], but also a unique high-potential (HP) state was found. On the basis of (57)Fe Mössbauer spectroscopy we attribute this HP form to a superoxidized state of the [4Fe4S] center proximal to the [NiFe] site. The unique environment of this cluster, characterized by a surplus cysteine coordination, is able to tune the redox potentials and make it compliant with the [4Fe4S](3+) state. It is actually the first example of a biological [4Fe4S] center that physiologically switches between 3+, 2+, and 1+ oxidation states within a very small potential range. We suggest that the (1 + /2+) redox couple serves the classical electron transfer reaction, whereas the superoxidation step is associated with a redox switch against oxidative stress.

Characterization of a unique [FeS] cluster in the electron transfer chain of the oxygen tolerant [NiFe] hydrogenase from Aquifex aeolicus

PubMed Central

Pandelia, Maria-Eirini; Nitschke, Wolfgang; Infossi, Pascale; Giudici-Orticoni, Marie-Thérèse; Bill, Eckhard; Lubitz, Wolfgang

2011-01-01

Iron-sulfur clusters are versatile electron transfer cofactors, ubiquitous in metalloenzymes such as hydrogenases. In the oxygen-tolerant Hydrogenase I from Aquifex aeolicus such electron “wires” form a relay to a diheme cytb, an integral part of a respiration pathway for the reduction of O2 to water. Amino acid sequence comparison with oxygen-sensitive hydrogenases showed conserved binding motifs for three iron-sulfur clusters, the nature and properties of which were unknown so far. Electron paramagnetic resonance spectra exhibited complex signals that disclose interesting features and spin-coupling patterns; by redox titrations three iron-sulfur clusters were identified in their usual redox states, a [3Fe4S] and two [4Fe4S], but also a unique high-potential (HP) state was found. On the basis of 57Fe Mössbauer spectroscopy we attribute this HP form to a superoxidized state of the [4Fe4S] center proximal to the [NiFe] site. The unique environment of this cluster, characterized by a surplus cysteine coordination, is able to tune the redox potentials and make it compliant with the [4Fe4S]3+ state. It is actually the first example of a biological [4Fe4S] center that physiologically switches between 3+, 2+, and 1+ oxidation states within a very small potential range. We suggest that the (1 + /2+) redox couple serves the classical electron transfer reaction, whereas the superoxidation step is associated with a redox switch against oxidative stress. PMID:21444783

Membrane Switches Check Seal Pressure

NASA Technical Reports Server (NTRS)

Hodgetts, P. J.; Stuckenberg, F. H.; Morrissey, E. T.

1984-01-01

Array of flexible membrane switches used to indicate closure of seal. Switch membrane responds to pressure exerted by rigid surface on compliant sealing medium and provides switch contacts monitored electronically. Membrane switches connected in series and placed under seal. When all switches are closed lamp or LED lights up, indicating requisite seal pressure has been realized at all switch positions. Principle used to ensure integrity of seals on refrigerator and oven doors, weatherstripping, hatches, spacecraft, airplanes, and submarines.

Optical Circuit Switched Protocol

NASA Technical Reports Server (NTRS)

Monacos, Steve P. (Inventor)

2000-01-01

The present invention is a system and method embodied in an optical circuit switched protocol for the transmission of data through a network. The optical circuit switched protocol is an all-optical circuit switched network and includes novel optical switching nodes for transmitting optical data packets within a network. Each optical switching node comprises a detector for receiving the header, header detection logic for translating the header into routing information and eliminating the header, and a controller for receiving the routing information and configuring an all optical path within the node. The all optical path located within the node is solely an optical path without having electronic storage of the data and without having optical delay of the data. Since electronic storage of the header is not necessary and the initial header is eliminated by the first detector of the first switching node. multiple identical headers are sent throughout the network so that subsequent switching nodes can receive and read the header for setting up an optical data path.

Reverse surface-polariton cherenkov radiation

PubMed Central

Tao, Jin; Wang, Qi Jie; Zhang, Jingjing; Luo, Yu

2016-01-01

The existence of reverse Cherenkov radiation for surface plasmons is demonstrated analytically. It is shown that in a metal-insulator-metal (MIM) waveguide, surface plasmon polaritons (SPPs) excited by an electron moving at a speed higher than the phase velocity of SPPs can generate Cherenkov radiation, which can be switched from forward to reverse direction by tuning the core thickness of the waveguide. Calculations are performed in both frequency and time domains, demonstrating that a radiation pattern with a backward-pointing radiation cone can be achieved at small waveguide core widths, with energy flow opposite to the wave vector of SPPs. Our study suggests the feasibility of generating and steering electron radiation in simple plasmonic systems, opening the gate for various applications such as velocity-selective particle detections. PMID:27477061

Synchronized femtosecond laser pulse switching system based nano-patterning technology

NASA Astrophysics Data System (ADS)

Sohn, Ik-Bu; Choi, Hun-Kook; Yoo, Dongyoon; Noh, Young-Chul; Sung, Jae-Hee; Lee, Seong-Ku; Ahsan, Md. Shamim; Lee, Ho

2017-07-01

This paper demonstrates the design and development of a synchronized femtosecond laser pulse switching system and its applications in nano-patterning of transparent materials. Due to synchronization, we are able to control the location of each irradiated laser pulse in any kind of substrate. The control over the scanning speed and scanning step of the laser beam enables us to pattern periodic micro/nano-metric holes, voids, and/or lines in various materials. Using the synchronized laser system, we pattern synchronized nano-holes on the surface of and inside various transparent materials including fused silica glass and polymethyl methacrylate to replicate any image or pattern on the surface of or inside (transparent) materials. We also investigate the application areas of the proposed synchronized femtosecond laser pulse switching system in a diverse field of science and technology, especially in optical memory, color marking, and synchronized micro/nano-scale patterning of materials.

The role of subjective frequency in language switching: An ERP investigation using masked priming

PubMed Central

Chauncey, Krysta; Grainger, Jonathan; Holcomb, Phillip J.

2012-01-01

Two experiments examined the nature of language-switching effects in a priming paradigm with event-related brain potential (ERP) recordings. primes and targets were always unrelated words but could be either from the same or different languages (Experiment 1) or from the same or a different frequency range (Experiment 2). Effects of switching language across prime and target differed as a function of the direction of the switch and prime duration in Experiment 1. Effects tended to be stronger with 100-ms prime durations than with 50-ms durations, and the expected pattern of greater negativity in the switch condition appeared earlier when primes were in L1 and targets in L2 than vice versa. Experiment 2 examined whether these language-switching effects could be due to differences in the subjective frequency of words in a bilingual’s two languages, by testing a frequency-switching manipulation within the L1. Effects of frequency switching were evident in the ERP waveforms, but the pattern did not resemble the language-switching effects, therefore suggesting that different mechanisms are at play. PMID:21264577

Atomic switch: atom/ion movement controlled devices for beyond von-neumann computers.

PubMed

Hasegawa, Tsuyoshi; Terabe, Kazuya; Tsuruoka, Tohru; Aono, Masakazu

2012-01-10

An atomic switch is a nanoionic device that controls the diffusion of metal ions/atoms and their reduction/oxidation processes in the switching operation to form/annihilate a conductive path. Since metal atoms can provide a highly conductive channel even if their cluster size is in the nanometer scale, atomic switches may enable downscaling to smaller than the 11 nm technology node, which is a great challenge for semiconductor devices. Atomic switches also possess novel characteristics, such as high on/off ratios, very low power consumption and non-volatility. The unique operating mechanisms of these devices have enabled the development of various types of atomic switch, such as gap-type and gapless-type two-terminal atomic switches and three-terminal atomic switches. Novel functions, such as selective volatile/nonvolatile, synaptic, memristive, and photo-assisted operations have been demonstrated. Such atomic switch characteristics can not only improve the performance of present-day electronic systems, but also enable development of new types of electronic systems, such as beyond von- Neumann computers. Copyright © 2012 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

Electronic switches and control circuits: A compilation

NASA Technical Reports Server (NTRS)

1971-01-01

The innovations in this updated series of compilations dealing with electronic technology represents a carefully selected collection of items on electronic switches and control circuits. Most of the items are based on well-known circuit design concepts that have been simplified or refined to meet NASA's demanding requirement for reliability, simplicity, fail-safe characteristics, and the capability of withstanding environmental extremes.

Wide Bandgap Extrinsic Photoconductive Switches

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

Sullivan, James S.

2013-07-03

Semi-insulating Gallium Nitride, 4H and 6H Silicon Carbide are attractive materials for compact, high voltage, extrinsic, photoconductive switches due to their wide bandgap, high dark resistance, high critical electric field strength and high electron saturation velocity. These wide bandgap semiconductors are made semi-insulating by the addition of vanadium (4H and 6HSiC) and iron (2H-GaN) impurities that form deep acceptors. These deep acceptors trap electrons donated from shallow donor impurities. The electrons can be optically excited from these deep acceptor levels into the conduction band to transition the wide bandgap semiconductor materials from a semi-insulating to a conducting state. Extrinsic photoconductivemore » switches with opposing electrodes have been constructed using vanadium compensated 6H-SiC and iron compensated 2H-GaN. These extrinsic photoconductive switches were tested at high voltage and high power to determine if they could be successfully used as the closing switch in compact medical accelerators.« less

Pressure-induced switching in ferroelectrics: Phase-field modeling, electrochemistry, flexoelectric effect, and bulk vacancy dynamics

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

Cao, Ye; Morozovska, Anna; Kalinin, Sergei V.

Pressure-induced polarization switching in ferroelectric thin films has emerged as a powerful method for domain patterning, allowing us to create predefined domain patterns on free surfaces and under thin conductive top electrodes. However, the mechanisms for pressure-induced polarization switching in ferroelectrics remain highly controversial, with flexoelectricity, polarization rotation and suppression, and bulk and surface electrochemical processes all being potentially relevant. Here we classify possible pressure-induced switching mechanisms, perform elementary estimates, and study in depth using phase-field modeling. Finally, we show that magnitudes of these effects are remarkably close and give rise to complex switching diagrams as a function of pressuremore » and film thickness with nontrivial topology or switchable and nonswitchable regions.« less

Pressure-induced switching in ferroelectrics: Phase-field modeling, electrochemistry, flexoelectric effect, and bulk vacancy dynamics

DOE PAGES

Cao, Ye; Morozovska, Anna; Kalinin, Sergei V.

2017-11-01

Pressure-induced polarization switching in ferroelectric thin films has emerged as a powerful method for domain patterning, allowing us to create predefined domain patterns on free surfaces and under thin conductive top electrodes. However, the mechanisms for pressure-induced polarization switching in ferroelectrics remain highly controversial, with flexoelectricity, polarization rotation and suppression, and bulk and surface electrochemical processes all being potentially relevant. Here we classify possible pressure-induced switching mechanisms, perform elementary estimates, and study in depth using phase-field modeling. Finally, we show that magnitudes of these effects are remarkably close and give rise to complex switching diagrams as a function of pressuremore » and film thickness with nontrivial topology or switchable and nonswitchable regions.« less

Solid state switch panel. [determination of optimum transducer type for required switches

NASA Technical Reports Server (NTRS)

Beenfeldt, E.

1973-01-01

An intensive study of various forms of transducers was conducted with application towards hermetically sealing the transducer and all electronics. The results of the study indicated that the Hall effect devices and a LED/phototransistor combination were the most practical for this type of application. Therefore, hardware was developed utilizing a magnet/Hall effect transducer for single action switches and LED/phototransistor transducers for rotary multiposition or potentiometer applications. All electronics could be housed in a hermetically sealed compartment. A number of switches were built and models were hermetically sealed to prove the feasibility of this type of fabrication. One of each type of switch was subjected to temperature cycling, vibration, and EMI tests. The results of these tests are presented.

Engineering electronic states of periodic and quasiperiodic chains by buckling

NASA Astrophysics Data System (ADS)

Mukherjee, Amrita; Nandy, Atanu; Chakrabarti, Arunava

2017-07-01

The spectrum of spinless, non-interacting electrons on a linear chain that is buckled in a non-uniform, quasiperiodic manner is investigated within a tight binding formalism. We have addressed two specific cases, viz., a perfectly periodic chain wrinkled in a quasiperiodic Fibonacci pattern, and a quasiperiodic Fibonacci chain, where the buckling also takes place in a Fibonacci pattern. The buckling brings distant neighbors in the parent chain to close proximity, which is simulated by a tunnel hopping amplitude. It is seen that, in the perfectly ordered case, increasing the strength of the tunnel hopping (that is, bending the segments more) absolutely continuous density of states is retained towards the edges of the band, while the central portion becomes fragmented and host subbands of narrowing widths containing extended, current carrying states, and multiple isolated bound states formed as a result of the bending. A switching ;on; and ;off; of the electronic transmission can thus be engineered by buckling. On the other hand, in the second example of a quasiperiodic Fibonacci chain, imparting a quasiperiodic buckling is found to generate continuous subband(s) destroying the usual multifractality of the energy spectrum. We present exact results based on a real space renormalization group analysis, that is corroborated by explicit calculation of the two terminal electronic transport.

A chameleon catalyst for nonheme iron-promoted olefin oxidation.

PubMed

Iyer, Shyam R; Javadi, Maedeh Moshref; Feng, Yan; Hyun, Min Young; Oloo, Williamson N; Kim, Cheal; Que, Lawrence

2014-11-18

We report the chameleonic reactivity of two nonheme iron catalysts for olefin oxidation with H2O2 that switch from nearly exclusive cis-dihydroxylation of electron-poor olefins to the exclusive epoxidation of electron-rich olefins upon addition of acetic acid. This switching suggests a common precursor to the nucleophilic oxidant proposed to Fe(III)-η(2)-OOH and electrophilic oxidant proposed to Fe(V)(O)(OAc), and reversible coordination of acetic acid as a switching pathway.

Explosive-driven, high speed, arcless switch

DOEpatents

Skogmo, P.J.; Tucker, T.J.

1987-07-14

An explosive-actuated, fast-acting arcless switch contains a highly conductive foil to carry high currents positioned adjacent a dielectric surface within a casing. At one side of the foil opposite the dielectric surface is an explosive which, when detonated, drives the conductive foil against the dielectric surface. A pattern of grooves in the dielectric surface ruptures the foil to establish a rupture path having a pattern corresponding to the pattern of the grooves. The impedance of the ruptured foil is greater than that of the original foil to divert high current to a load. Planar and cylindrical embodiments of the switch are disclosed. 7 figs.

Cryogenic switched MOSFET characterization

NASA Technical Reports Server (NTRS)

1981-01-01

Both p channel and n channel enhancement mode MOSFETs can be readily switched on and off at temperatures as low as 2.8 K so that switch sampled readout of a VLWIR Ge:Ga focal plane is electronically possible. Noise levels as low as 100 rms electrons per sample (independent of sample rate) can be achieved using existing p channel MOSFETs, at overall rates up to 30,000 samples/second per multiplexed channel (e.g., 32 detectors at a rate of almost 1,000 frames/second). Run of the mill devices, including very low power dissipation n channel FETs would still permit noise levels of the order of 500 electrons/sample.

Qualitative Differences between Bilingual Language Control and Executive Control: Evidence from Task-Switching

PubMed Central

Calabria, Marco; Hernández, Mireia; Branzi, Francesca M.; Costa, Albert

2012-01-01

Previous research has shown that highly proficient bilinguals have comparable switch costs in both directions when they switch between languages (L1 and L2), the so-called “symmetrical switch cost” effect. Interestingly, the same symmetry is also present when they switch between L1 and a much weaker L3. These findings suggest that highly proficient bilinguals develop a language control system that seems to be insensitive to language proficiency. In the present study, we explore whether the pattern of symmetrical switch costs in language switching tasks generalizes to a non-linguistic switching task in the same group of highly proficient bilinguals. The end goal of this is to assess whether bilingual language control (bLC) can be considered as subsidiary to domain-general executive control (EC). We tested highly proficient Catalan–Spanish bilinguals both in a linguistic switching task and in a non-linguistic switching task. In the linguistic task, participants named pictures in L1 and L2 (Experiment 1) or L3 (Experiment 2) depending on a cue presented with the picture (a flag). In the non-linguistic task, the same participants had to switch between two card sorting rule-sets (color and shape). Overall, participants showed symmetrical switch costs in the linguistic switching task, but not in the non-linguistic switching task. In a further analysis, we observed that in the linguistic switching task the asymmetry of the switch costs changed across blocks, while in the non-linguistic switching task an asymmetrical switch cost was observed throughout the task. The observation of different patterns of switch costs in the linguistic and the non-linguistic switching tasks suggest that the bLC system is not completely subsidiary to the domain-general EC system. PMID:22275905

Contralateral disconnection of the rat prelimbic cortex and dorsomedial striatum impairs cue-guided behavioral switching

PubMed Central

Baker, Phillip M.

2014-01-01

Switches in reward outcomes or reward-predictive cues are two fundamental ways in which information is used to flexibly shift response patterns. The rat prelimbic cortex and dorsomedial striatum support behavioral flexibility based on a change in outcomes. The present experiments investigated whether these two brain regions are necessary for conditional discrimination performance in which a switch in reward-predictive cues occurs every three to six trials. The GABA agonists baclofen and muscimol infused into the prelimbic cortex significantly impaired performance leading rats to adopt an inappropriate turn strategy. The NMDA receptor antagonist D-AP5 infused into the dorsomedial striatum or prelimbic cortex and dorsomedial striatum contralateral disconnection impaired performance due to a rat failing to switch a response choice for an entire trial block in about two out of 13 test blocks. In an additional study, contralateral disconnection did not affect nonswitch discrimination performance. The results suggest that the prelimbic cortex and dorsomedial striatum are necessary to support cue-guided behavioral switching. The prelimbic cortex may be critical for generating alternative response patterns while the dorsomedial striatum supports the selection of an appropriate response when cue information must be used to flexibly switch response patterns. PMID:25028395

Modulation of ICT probability in bi(polyarene)-based O-BODIPYs: towards the development of low-cost bright arene-BODIPY dyads.

PubMed

Gartzia-Rivero, Leire; Sánchez-Carnerero, Esther M; Jiménez, Josue; Bañuelos, Jorge; Moreno, Florencio; Maroto, Beatriz L; López-Arbeloa, Iñigo; de la Moya, Santiago

2017-09-12

We report the synthesis, and spectroscopic and electrochemical properties of a selected library of novel spiranic O-BODIPYs bearing a phenol-based bi(polyarene) unit tethered to the boron center through oxygen atoms. These dyes constitute an interesting family of arene-BODIPY dyads useful for the development of photonic applications due to their synthetic accessibility and tunable photonic properties. It is demonstrated that the electron-donor capability of the involved arene moiety switches on a non-emissive intramolecular charge transfer (ICT) state, which restricts the fluorescence efficiency of the dyad. Interestingly, the influence of this non-radiative deactivation channel can be efficiently modulated by the substitution pattern, either at the dipyrrin ligand or at the polyarene moiety. Thus, dyads featuring electron-rich dipyrrin and electron-poor polyarene show lower or almost negligible ICT probability, and hence display bright fluorescence upon dual excitation at far-away spectral regions. This synthetic approach has allowed the easy development of low-cost efficient ultraviolet-absorbing visible-emitting cassettes by selecting properly the substitution pattern of the involved key units, dipyrrin and bi(polyarene), to modulate not only absorption and emission wavelengths, but also fluorescence efficiencies.

Preliminary study, analysis and design for a power switch for digital engine actuators

NASA Technical Reports Server (NTRS)

Beattie, E. C.; Zickwolf, H. C., Jr.

1979-01-01

Innovative control configurations using high temperature switches to operate actuator driving solenoids were studied. The impact on engine control system life cycle costs and reliability of electronic control and (ECU) heat dissipation due to power conditioning and interface drivers were addressed. Various power supply and actuation schemes were investigated, including optical signal transmission and electronics on the actuator, engine driven alternator, and inside the ECU. The use of a switching shunt power conditioner results in the most significant decrease in heat dissipation within the ECU. No overall control system reliability improvement is projected by the use of remote high temperature switches for solenoid drivers.

Adaptive packet switch with an optical core (demonstrator)

NASA Astrophysics Data System (ADS)

Abdo, Ahmad; Bishtein, Vadim; Clark, Stewart A.; Dicorato, Pino; Lu, David T.; Paredes, Sofia A.; Taebi, Sareh; Hall, Trevor J.

2004-11-01

A three-stage opto-electronic packet switch architecture is described consisting of a reconfigurable optical centre stage surrounded by two electronic buffering stages partitioned into sectors to ease memory contention. A Flexible Bandwidth Provision (FBP) algorithm, implemented on a soft-core processor, is used to change the configuration of the input sectors and optical centre stage to set up internal paths that will provide variable bandwidth to serve the traffic. The switch is modeled by a bipartite graph built from a service matrix, which is a function of the arriving traffic. The bipartite graph is decomposed by solving an edge-colouring problem and the resulting permutations are used to configure the switch. Simulation results show that this architecture exhibits a dramatic reduction of complexity and increased potential for scalability, at the price of only a modest spatial speed-up k, 1

Fast infrared response of YBCO thin films

NASA Technical Reports Server (NTRS)

Ballentine, P. H.; Kadin, A. M.; Donaldson, W. R.; Scofield, J. H.; Bajuk, L.

1990-01-01

The response to short infrared pulses of some epitaxial YBCO films prepared by sputter deposition and by electron-beam evaporation is reported. The response is found to be essentially bolometric on the ns timescale, with some indirect hints of nonequilibrium electron transport on the ps scale. Fast switching could be obtained either by biasing the switch close to the critical current or by cooling the film below about 20 K. These results are encouraging for potential application to a high-current optically-triggered opening switch.

Ultrananocrystalline diamond films with optimized dielectric properties for advanced RF MEMS capacitive switches

DOEpatents

Sumant, Anirudha V.; Auciello, Orlando H.; Mancini, Derrick C.

2013-01-15

An efficient deposition process is provided for fabricating reliable RF MEMS capacitive switches with multilayer ultrananocrystalline (UNCD) films for more rapid recovery, charging and discharging that is effective for more than a billion cycles of operation. Significantly, the deposition process is compatible for integration with CMOS electronics and thereby can provide monolithically integrated RF MEMS capacitive switches for use with CMOS electronic devices, such as for insertion into phase array antennas for radars and other RF communication systems.

Spontaneous switching among multiple spatio-temporal patterns in three-oscillator systems constructed with oscillatory cells of true slime mold

NASA Astrophysics Data System (ADS)

Takamatsu, Atsuko

2006-11-01

Three-oscillator systems with plasmodia of true slime mold, Physarum polycephalum, which is an oscillatory amoeba-like unicellular organism, were experimentally constructed and their spatio-temporal patterns were investigated. Three typical spatio-temporal patterns were found: rotation ( R), partial in-phase ( PI), and partial anti-phase with double frequency ( PA). In pattern R, phase differences between adjacent oscillators were almost 120 ∘. In pattern PI, two oscillators were in-phase and the third oscillator showed anti-phase against the two oscillators. In pattern PA, two oscillators showed anti-phase and the third oscillator showed frequency doubling oscillation with small amplitude. Actually each pattern is not perfectly stable but quasi-stable. Interestingly, the system shows spontaneous switching among the multiple quasi-stable patterns. Statistical analyses revealed a characteristic in the residence time of each pattern: the histograms seem to have Gamma-like distribution form but with a sharp peak and a tail on the side of long period. That suggests the attractor of this system has complex structure composed of at least three types of sub-attractors: a “Gamma attractor”-involved with several Poisson processes, a “deterministic attractor”-the residence time is deterministic, and a “stable attractor”-each pattern is stable. When the coupling strength was small, only the Gamma attractor was observed and switching behavior among patterns R, PI, and PA almost always via an asynchronous pattern named O. A conjecture is as follows: Internal/external noise exposes each pattern of R, PI, and PA coexisting around bifurcation points: That is observed as the Gamma attractor. As coupling strength increases, the deterministic attractor appears then followed by the stable attractor, always accompanied with the Gamma attractor. Switching behavior could be caused by regular existence of the Gamma attractor.

Transparent Electrochemical Gratings from a Patterned Bistable Silver Mirror.

PubMed

Park, Chihyun; Na, Jongbeom; Han, Minsu; Kim, Eunkyoung

2017-07-25

Silver mirror patterns were formed reversibly on a polystyrene (PS)-patterned electrode to produce gratings through the electrochemical reduction of silver ions. The electrochemical gratings exhibited high transparency (T > 95%), similar to a see-through window, by matching the refractive index of the grating pattern with the surrounding medium. The gratings switch to a diffractive state upon the formation of a mirror pattern (T < 5%) with a high diffraction efficiency up to 40%, providing reversible diffractive gratings. The diffraction state was maintained in the voltage-off state (V-off) for 40 min, which demonstrated bistable reversible electrochemical grating (BREG) behavior. By carefully combining the BREGs through period matching, dual-color switching was achieved within the full color region, which exhibited three distinct optical switching states between -2.5, 0, and +2.5 V. The wide range of light tenability using the metallic BREGs developed herein enabled IR modulation, NIR light reflection, and on-demand heat transfer.

A new coupling mechanism between two graphene electron waveguides for ultrafast switching

NASA Astrophysics Data System (ADS)

Huang, Wei; Liang, Shi-Jun; Kyoseva, Elica; Ang, Lay Kee

2018-03-01

In this paper, we report a novel coupling between two graphene electron waveguides, in analogy the optical waveguides. The design is based on the coherent quantum mechanical tunneling of Rabi oscillation between the two graphene electron waveguides. Based on this coupling mechanism, we propose that it can be used as an ultrafast electronic switching device. Based on a modified coupled mode theory, we construct a theoretical model to analyze the device characteristics, and predict that the switching speed is faster than 1 ps and the on-off ratio exceeds 106. Due to the long mean free path of electrons in graphene at room temperature, the proposed design avoids the limitation of low temperature operation required in the traditional design by using semiconductor quantum-well structure. The layout of our design is similar to that of a standard complementary metal-oxide-semiconductor transistor that should be readily fabricated with current state-of-art nanotechnology.

Fast packet switch architectures for broadband integrated services digital networks

NASA Technical Reports Server (NTRS)

Tobagi, Fouad A.

1990-01-01

Background information on networking and switching is provided, and the various architectures that have been considered for fast packet switches are described. The focus is solely on switches designed to be implemented electronically. A set of definitions and a brief description of the functionality required of fast packet switches are given. Three basic types of packet switches are identified: the shared-memory, shared-medium, and space-division types. Each of these is described, and examples are given.

Control strategy based on SPWM switching patterns for grid connected photovoltaic inverter

NASA Astrophysics Data System (ADS)

Hassaine, L.; Mraoui, A.

2017-02-01

Generally, for lower installation of photovoltaic systems connected to the grid, pulse width modulation (PWM) is a widely used technique for controlling the voltage source inverters injects currents into the grid. The current injected must be sinusoidal with reduced harmonic distortion. In this paper, a digital implementation of a control strategy based on PWM switching patterns for an inverter for photovoltaic system connected to the grid is presented. This strategy synchronize a sinusoidal inverter output current with a grid voltage The digital implementation of the proposed PWM switching pattern when is compared with the conventional one exhibit the advantage: Simplicity, reduction of the memory requirements and power calculation for the control

Electron transport and light-harvesting switches in cyanobacteria

PubMed Central

Mullineaux, Conrad W.

2014-01-01

Cyanobacteria possess multiple mechanisms for regulating the pathways of photosynthetic and respiratory electron transport. Electron transport may be regulated indirectly by controlling the transfer of excitation energy from the light-harvesting complexes, or it may be more directly regulated by controlling the stoichiometry, localization, and interactions of photosynthetic and respiratory electron transport complexes. Regulation of the extent of linear vs. cyclic electron transport is particularly important for controlling the redox balance of the cell. This review discusses what is known of the regulatory mechanisms and the timescales on which they occur, with particular regard to the structural reorganization needed and the constraints imposed by the limited mobility of membrane-integral proteins in the crowded thylakoid membrane. Switching mechanisms requiring substantial movement of integral thylakoid membrane proteins occur on slower timescales than those that require the movement only of cytoplasmic or extrinsic membrane proteins. This difference is probably due to the restricted diffusion of membrane-integral proteins. Multiple switching mechanisms may be needed to regulate electron transport on different timescales. PMID:24478787

Variable reluctance switch avoids contact corrosion and contact bounce

NASA Technical Reports Server (NTRS)

Watson, P. C.

1967-01-01

Variable reluctance switch avoids contact corrosion and bounce in a hostile environment. It consists of a wire-wound magnetic core and moveable bridge piece that alters the core flux pattern to produce an electrical output useful for switching control media.

High-Speed, high-power, switching transistor

NASA Technical Reports Server (NTRS)

Carnahan, D.; Ohu, C. K.; Hower, P. L.

1979-01-01

Silicon transistor rate for 200 angstroms at 400 to 600 volts combines switching speed of transistors with ruggedness, power capacity of thyristor. Transistor introduces unique combination of increased power-handling capability, unusally low saturation and switching losses, and submicrosecond switching speeds. Potential applications include high power switching regulators, linear amplifiers, chopper controls for high frequency electrical vehicle drives, VLF transmitters, RF induction heaters, kitchen cooking ranges, and electronic scalpels for medical surgery.

Water Activated Graphene Oxide Transfer Using Wax Printed Membranes for Fast Patterning of a Touch Sensitive Device.

PubMed

Baptista-Pires, Luis; Mayorga-Martínez, Carmen C; Medina-Sánchez, Mariana; Montón, Helena; Merkoçi, Arben

2016-01-26

We demonstrate a graphene oxide printing technology using wax printed membranes for the fast patterning and water activation transfer using pressure based mechanisms. The wax printed membranes have 50 μm resolution, longtime stability and infinite shaping capability. The use of these membranes complemented with the vacuum filtration of graphene oxide provides the control over the thickness. Our demonstration provides a solvent free methodology for printing graphene oxide devices in all shapes and all substrates using the roll-to-roll automatized mechanism present in the wax printing machine. Graphene oxide was transferred over a wide variety of substrates as textile or PET in between others. Finally, we developed a touch switch sensing device integrated in a LED electronic circuit.

Resistive switching behavior in oxygen ion irradiated TiO2-x films

NASA Astrophysics Data System (ADS)

Barman, A.; Saini, C. P.; Sarkar, P. K.; Bhattacharjee, G.; Bhattacharya, G.; Srivastava, S.; Satpati, B.; Kanjilal, D.; Ghosh, S. K.; Dhar, S.; Kanjilal, A.

2018-02-01

The room temperature resistive switching behavior in 50 keV O+-ion irradiated TiO2-x layers at an ion fluence of 5  ×  1016 ions cm-2 is reported. A clear transformation from columnar to layered polycrystalline films is revealed by transmission electron microscopy with increasing ion fluence, while the complementary electron energy loss spectroscopy suggests an evolution of oxygen vacancy (OV) in TiO2-x matrix. This is further verified by determining electron density with the help of x-ray reflectivity. Both local and device current-voltage measurements illustrate that the ion-beam induced OVs play a key role in bistable resistive switching mechanism.

Reviewing the Challenges and Opportunities Presented by Code Switching and Mixing in Bangla

ERIC Educational Resources Information Center

Hasan, Md. Kamrul; Akhand, Mohd. Moniruzzaman

2015-01-01

This paper investigates the issues related to code-switching/code-mixing in an ESL context. Some preliminary data on Bangla-English code-switching/code-mixing has been analyzed in order to determine which structural pattern of code-switching/code-mixing is predominant in different social strata. This study also explores the relationship of…

Reviewing the Challenges and Opportunities Presented by Code Switching and Mixing in Bangla

ERIC Educational Resources Information Center

Hasan, Md. Kamrul; Akhand, Mohd. Moniruzzaman

2014-01-01

This paper investigates the issues related to code-switching/code-mixing in an ESL context. Some preliminary data on Bangla-English code-switching/code-mixing has been analyzed in order to determine which structural pattern of code-switching/code-mixing is predominant in different social strata. This study also explores the relationship of…

Nanoionics-Based Switches for Radio-Frequency Applications

NASA Technical Reports Server (NTRS)

Nessel, James; Lee, Richard

2010-01-01

Nanoionics-based devices have shown promise as alternatives to microelectromechanical systems (MEMS) and semiconductor diode devices for switching radio-frequency (RF) signals in diverse systems. Examples of systems that utilize RF switches include phase shifters for electronically steerable phased-array antennas, multiplexers, cellular telephones and other radio transceivers, and other portable electronic devices. Semiconductor diode switches can operate at low potentials (about 1 to 3 V) and high speeds (switching times of the order of nanoseconds) but are characterized by significant insertion loss, high DC power consumption, low isolation, and generation of third-order harmonics and intermodulation distortion (IMD). MEMS-based switches feature low insertion loss (of the order of 0.2 dB), low DC power consumption (picowatts), high isolation (>30 dB), and low IMD, but contain moving parts, are not highly reliable, and must be operated at high actuation potentials (20 to 60 V) generated and applied by use of complex circuitry. In addition, fabrication of MEMS is complex, involving many processing steps. Nanoionics-based switches offer the superior RF performance and low power consumption of MEMS switches, without need for the high potentials and complex circuitry necessary for operation of MEMS switches. At the same time, nanoionics-based switches offer the high switching speed of semiconductor devices. Also, like semiconductor devices, nanoionics-based switches can be fabricated relatively inexpensively by use of conventional integrated-circuit fabrication techniques. More over, nanoionics-based switches have simple planar structures that can easily be integrated into RF power-distribution circuits.

Electronic interaction and bipolar resistive switching in copper oxide-multilayer graphene hybrid interface: Graphene as an oxygen ion storage and blocking layer

NASA Astrophysics Data System (ADS)

Singh, Bharti; Mehta, B. R.; Govind, Feng, X.; Müllen, Klaus

2011-11-01

This study reports a bipolar resistive switching device based on copper oxide (CuO)-multilayer graphene (MLG) hybrid interface in complete contrast to the ohmic and rectifying characteristics of junctions based on individual MLG and CuO layers. The observed shift and the occurrence of additional O1s, Cu2p, and C1s core level peaks indicate electronic interaction at the hybrid interfacial layer. Large changes in the resistive switching parameters on changing the ambient conditions from air to vacuum establish the important role of MLG as oxygen ion storage and blocking layer towards the observed resistive switching effect.

Pattern Formations for Optical Switching Using Cold Atoms as a Nonlinear Medium

NASA Astrophysics Data System (ADS)

Schmittberger, Bonnie; Greenberg, Joel; Gauthier, Daniel

2011-05-01

The study of spatio-temporal pattern formation in nonlinear optical systems has both led to an increased understanding of nonlinear dynamics as well as given rise to sensitive new methods for all-optical switching. Whereas the majority of past experiments utilized warm atomic vapors as nonlinear media, we report the first observation of an optical instability leading to pattern formation in a cloud of cold Rubidium atoms. When we shine a pair of counterpropagating pump laser beams along the pencil-shaped cloud's long axis, new beams of light are generated along cones centered on the trap. This generated light produces petal-like patterns in the plane orthogonal to the pump beams that can be used for optical switching. We gratefully acknowledge the financial support of the NSF through Grant #PHY-0855399 and the DARPA Slow Light Program.

Low inductance power electronics assembly

DOEpatents

Herron, Nicholas Hayden; Mann, Brooks S.; Korich, Mark D.; Chou, Cindy; Tang, David; Carlson, Douglas S.; Barry, Alan L.

2012-10-02

A power electronics assembly is provided. A first support member includes a first plurality of conductors. A first plurality of power switching devices are coupled to the first support member. A first capacitor is coupled to the first support member. A second support member includes a second plurality of conductors. A second plurality of power switching devices are coupled to the second support member. A second capacitor is coupled to the second support member. The first and second pluralities of conductors, the first and second pluralities of power switching devices, and the first and second capacitors are electrically connected such that the first plurality of power switching devices is connected in parallel with the first capacitor and the second capacitor and the second plurality of power switching devices is connected in parallel with the second capacitor and the first capacitor.

Switching behaviors of graphene-boron nitride nanotube heterojunctions

DOE PAGES

Parashar, Vyom; Durand, Corentin P.; Hao, Boyi; ...

2015-07-20

High electron mobility of graphene has enabled their application in high-frequency analogue devices but their gapless nature has hindered their use in digital switches. In contrast, the structural analogous, h-BN sheets and BN nanotubes (BNNTs) are wide band gap insulators. Here we show that the growth of electrically insulating BNNTs on graphene can enable the use of graphene as effective digital switches. These graphene-BNNT heterojunctions were characterized at room temperature by four-probe scanning tunneling microscopy (4-probe STM) under real-time monitoring of scanning electron microscopy (SEM). A switching ratio as high as 105 at a turn-on voltage as low as 0.5more » V were recorded. Simulation by density functional theory (DFT) suggests that mismatch of the density of states (DOS) is responsible for these novel switching behaviors.« less

Electronic transport properties of a quinone-based molecular switch

NASA Astrophysics Data System (ADS)

Zheng, Ya-Peng; Bian, Bao-An; Yuan, Pei-Pei

2016-09-01

In this paper, we carried out first-principles calculations based on density functional theory and non-equilibrium Green's function to investigate the electronic transport properties of a quinone-based molecule sandwiched between two Au electrodes. The molecular switch can be reversibly switched between the reduced hydroquinone (HQ) and oxidized quinone (Q) states via redox reactions. The switching behavior of two forms is analyzed through their I- V curves, transmission spectra and molecular projected self-consistent Hamiltonian at zero bias. Then we discuss the transmission spectra of the HQ and Q forms at different bias, and explain the oscillation of current according to the transmission eigenstates of LUMO energy level for Q form. The results suggest that this kind of a quinone-based molecule is usable as one of the good candidates for redox-controlled molecular switches.

47 CFR 36.121 - General.

Code of Federal Regulations, 2013 CFR

2013-10-01

...: Central Office Switching Account 2210. Non-digital Switching Account 2211. Digital Electronic Switching... Account 2231. Circuit Equipment Account 2232. (b) Records of the cost of central office equipment are... directly to that category, e.g., 130 volt power supply provided for circuit equipment. The cost of...

47 CFR 36.121 - General.

Code of Federal Regulations, 2014 CFR

2014-10-01

...: Central Office Switching Account 2210. Non-digital Switching Account 2211. Digital Electronic Switching... Account 2231. Circuit Equipment Account 2232. (b) Records of the cost of central office equipment are... directly to that category, e.g., 130 volt power supply provided for circuit equipment. The cost of...

47 CFR 36.121 - General.

Code of Federal Regulations, 2011 CFR

2011-10-01

...: Central Office Switching Account 2210. Non-digital Switching Account 2211. Digital Electronic Switching... Account 2231. Circuit Equipment Account 2232. (b) Records of the cost of central office equipment are... directly to that category, e.g., 130 volt power supply provided for circuit equipment. The cost of...

47 CFR 36.121 - General.

Code of Federal Regulations, 2010 CFR

2010-10-01

...: Central Office Switching Account 2210. Non-digital Switching Account 2211. Digital Electronic Switching... Account 2231. Circuit Equipment Account 2232. (b) Records of the cost of central office equipment are... directly to that category, e.g., 130 volt power supply provided for circuit equipment. The cost of...

47 CFR 36.121 - General.

Code of Federal Regulations, 2012 CFR

2012-10-01

...: Central Office Switching Account 2210. Non-digital Switching Account 2211. Digital Electronic Switching... Account 2231. Circuit Equipment Account 2232. (b) Records of the cost of central office equipment are... directly to that category, e.g., 130 volt power supply provided for circuit equipment. The cost of...

Effects of the electron-phonon coupling activation in collision cascades

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

Zarkadoula, Eva; Samolyuk, German; Weber, William J.

Using the two-temperature (2T-MD) model in molecular dynamics simulations, here we investigate the condition of switching the electronic stopping term off when the electron-phonon coupling is activated in the damage production due to 50 keV Ni ion cascades in Ni and equiatomic NiFe. Additionally we investigate the effect of the electron-phonon coupling activation time in the damage production. We find that the switching condition has negligible effect in the produced damage, while the choice of the activation time of the electron-phonon coupling can affect the amount of surviving damage.

Effects of the electron-phonon coupling activation in collision cascades

DOE PAGES

Zarkadoula, Eva; Samolyuk, German; Weber, William J.

2017-04-20

Using the two-temperature (2T-MD) model in molecular dynamics simulations, here we investigate the condition of switching the electronic stopping term off when the electron-phonon coupling is activated in the damage production due to 50 keV Ni ion cascades in Ni and equiatomic NiFe. Additionally we investigate the effect of the electron-phonon coupling activation time in the damage production. We find that the switching condition has negligible effect in the produced damage, while the choice of the activation time of the electron-phonon coupling can affect the amount of surviving damage.

Organic-based molecular switches for molecular electronics.

PubMed

Fuentes, Noelia; Martín-Lasanta, Ana; Alvarez de Cienfuegos, Luis; Ribagorda, Maria; Parra, Andres; Cuerva, Juan M

2011-10-05

In a general sense, molecular electronics (ME) is the branch of nanotechnology which studies the application of molecular building blocks for the fabrication of electronic components. Among the different types of molecules, organic compounds have been revealed as promising candidates for ME, due to the easy access, great structural diversity and suitable electronic and mechanical properties. Thanks to these useful capabilities, organic molecules have been used to emulate electronic devices at the nanoscopic scale. In this feature article, we present the diverse strategies used to develop organic switches towards ME with special attention to non-volatile systems.

Electron beam magnetic switch for a plurality of free electron lasers

DOEpatents

Schlitt, Leland G.

1984-01-01

Apparatus for forming and utilizing a sequence of electron beam segments, each of the same temporal length (substantially 15 nsec), with consecutive beams being separated by a constant time interval of the order of 3 nsec. The beam sequence is used for simultaneous inputs to a plurality of wiggler magnet systems that also accept the laser beams to be amplified by interaction with the co-propagating electron beams. The electron beams are arranged substantially in a circle to allow proper distribution of and simultaneous switching out of the beam segments to their respective wiggler magnets.

Therapeutically interchangeable? A study of real-world outcomes associated with switching basal insulin analogues among US patients with type 2 diabetes mellitus using electronic medical records data.

PubMed

Levin, P; Wei, W; Miao, R; Ye, F; Xie, L; Baser, O; Gill, J

2015-03-01

To evaluate real-world clinical outcomes for switching basal insulin analogues [insulin glargine (GLA) and insulin detemir (DET)] among US patients with type 2 diabetes mellitus (T2DM). Using the GE Centricity Electronic Medical Records database, this retrospective study examined two cohorts: cohort 1, comprising patients previously on GLA and then either switching to DET (DET-S) or continuing with GLA (GLA-C); and cohort 2, comprising patients previously on DET and then either switching to GLA (GLA-S) or continuing with DET (DET-C). Within each cohort, treatment groups were propensity-score-matched on baseline characteristics. At 1-year follow-up, insulin treatment patterns, glycated haemoglobin (HbA1c) levels, hypoglycaemic events, weight and body mass index (BMI) were evaluated. The analysis included 13 942 patients: cohort 1: n = 10 657 (DET-S, n = 1797 matched to GLA-C, n = 8860) and cohort 2: n = 3285 (GLA-S, n = 858 matched to DET-C, n = 2427). Baseline characteristics were similar between the treatment groups in each cohort. At 1-year follow-up, in cohort 1, patients in the DET-S subgroup were significantly less persistent with treatment, more likely to use a rapid-acting insulin analogue, had higher HbA1c values, lower HbA1c reductions and lower proportions of patients achieving HbA1c <7.0 or <8.0% compared with patients in the GLA-C subgroup, while hypoglycaemia rates and BMI/weight values and change from baseline were similar in the two subgroups. In cohort 2, overall, there were contrasting findings between patients in the GLA-S and those in the DET-C subgroup. This study showed contrasting results when patients with T2DM switched between basal insulin analogues, although these preliminary results may be subject to limitations in the analysis. Nevertheless, this study calls into question the therapeutic interchangeability of GLA and DET, and this merits further investigation. © 2014 The Authors. Diabetes, Obesity and Metabolism published by John Wiley & Sons Ltd.

Electron-impact ionization and electron attachment cross sections of radicals important in transient gaseous discharges

NASA Technical Reports Server (NTRS)

Lee, Long C.; Srivastava, Santosh K.

1990-01-01

Electron-impact ionization and electron attachment cross sections of radicals and excited molecules were measured using an apparatus that consists of an electron beam, a molecular beam and a laser beam. The information obtained is needed for the pulse power applications in the areas of high power gaseous discharge switches, high energy lasers, particle beam experiments, and electromagnetic pulse systems. The basic data needed for the development of optically-controlled discharge switches were also investigated. Transient current pulses induced by laser irradiation of discharge media were observed and applied for the study of electron-molecule reaction kinetics in gaseous discharges.

Wide Bandgap Extrinsic Photoconductive Switches

NASA Astrophysics Data System (ADS)

Sullivan, James Stephen

Wide Bandgap Extrinsic Photoconductive Switches Semi-insulating Gallium Nitride, 4H and 6H Silicon Carbide are attractive materials for compact, high voltage, extrinsic, photoconductive switches due to their wide bandgap, high dark resistance, high critical electric field strength and high electron saturation velocity. These wide bandgap semiconductors are made semi-insulating by the addition of vanadium (4H and 6H-SiC) and iron (2H-GaN) impurities that form deep acceptors. These deep acceptors trap electrons donated from shallow donor impurities. The electrons can be optically excited from these deep acceptor levels into the conduction band to transition the wide bandgap semiconductor materials from a semi-insulating to a conducting state. Extrinsic photoconductive switches with opposing electrodes have been constructed using vanadium compensated 6H-SiC and iron compensated 2H-GaN. These extrinsic photoconductive switches were tested at high voltage and high power to determine if they could be successfully used as the closing switch in compact medical accelerators. The successful development of a vanadium compensated, 6H-SiC extrinsic photoconductive switch for use as a closing switch for compact accelerator applications was realized by improvements made to the vanadium, nitrogen and boron impurity densities. The changes made to the impurity densities were based on the physical intuition outlined and simple rate equation models. The final 6H-SiC impurity 'recipe' calls for vanadium, nitrogen and boron densities of 2.5 e17 cm-3, 1.25e17 cm-3 and ≤ 1e16 cm-3, respectively. This recipe was originally developed to maximize the quantum efficiency of the vanadium compensated 6H-SiC, while maintaining a thermally stable semi-insulating material. The rate equation models indicate that, besides increasing the quantum efficiency, the impurity recipe should be expected to also increase the carrier recombination time. Three generations of 6H-SiC materials were tested. The third generation vanadium compensated 6H-SiC has average impurity densities close to the recipe values. Extrinsic photoconductive switches constructed from the third generation vanadium compensated, 6H-SiC, 1 mm thick, 1 cm2, substrates have achieved high power operation at 16 kV with pulsed currents exceeding 1400 Amperes and a minimum on resistance of 1 ohm. The extrinsic photoconductive switch performance of the third generation 6H-SiC material was improved by a factor of up to 50 for excitation at the 532 nm wavelength compared to the initial 6H-SiC material. Switches based on this material have been incorporated into a prototype compact proton medical accelerator being developed by the Compact Particle Acceleration Corporation (CPAC). The vanadium compensated, 6H-SiC, extrinsic photoconductive switch operates differently when excited by 1064, or 532 nm, wavelength light. The 6H-SiC extrinsic photoconductive switch is a unipolar device when excited with 1064 nm light. The carriers are electrons excited from filled vanadium acceptor levels and other electron traps located within 1.17 eV of the conduction band. The switch is bipolar at 532 nm since the carriers consist of holes, as well as electrons. The holes are primarily generated by the excitation of valence band electrons into empty trap/acceptor levels and by two-photon absorption. Carrier generation by two-photon absorption becomes more important at high applied optical intensity at 532 nm and contributes to the supralinear behavior of switch conductance as a function of optical power. The 6H-SiC switch material is trap dominated at low nitrogen to vanadium ratios. The trap dominated vanadium compensated 6H-SiC exhibits low quantum efficiency when excited with 1064 and 532 nm light and has a carrier recombination time of ˜ 150 - 300 ps. The vanadium compensated 6H-SiC transitions to an impurity dominated material as the ratio of nitrogen to vanadium is increased to 0.5. The increased nitrogen doping produces a material with much higher quantum efficiency and carrier recombination time of 0.9 to 1.0 ns. The iron compensated 2H-GaN did not perform well as an extrinsic photoconductive switch. The density of carriers generated at 1064 nm was, low indicating that there were very few electrons trapped in the iron acceptor level located at 0.5 - 0.6 eV below the conduction band. Carrier generation at 532 nm was dominated by two photon absorption resulting in the switch conductance increasing as the square of applied optical intensity. A minimum switch resistance of 0.8 ohms was calculated for the 400 nm thick, 1.2 by 1.2 cm, 2H-GaN switch for an applied optical intensity of 41.25 MW/cm2. An optical intensity of ˜ 70 MW/cm2 at 532 nm would be required to achieve a 0.8 ohm on resistance for a 1 mm thick, 1 cm2, 2H-GaN switch.

Organic bioelectronics for electronic-to-chemical translation in modulation of neuronal signaling and machine-to-brain interfacing.

PubMed

Larsson, Karin C; Kjäll, Peter; Richter-Dahlfors, Agneta

2013-09-01

A major challenge when creating interfaces for the nervous system is to translate between the signal carriers of the nervous system (ions and neurotransmitters) and those of conventional electronics (electrons). Organic conjugated polymers represent a unique class of materials that utilizes both electrons and ions as charge carriers. Based on these materials, we have established a series of novel communication interfaces between electronic components and biological systems. The organic electronic ion pump (OEIP) presented in this review is made of the polymer-polyelectrolyte system poly(3,4-ethylenedioxythiophene):poly(styrenesulfonate) (PEDOT:PSS). The OEIP translates electronic signals into electrophoretic migration of ions and neurotransmitters. We demonstrate how spatio-temporally controlled delivery of ions and neurotransmitters can be used to modulate intracellular Ca(2+) signaling in neuronal cells in the absence of convective disturbances. The electronic control of delivery enables strict control of dynamic parameters, such as amplitude and frequency of Ca(2+) responses, and can be used to generate temporal patterns mimicking naturally occurring Ca(2+) oscillations. To enable further control of the ionic signals we developed the electrophoretic chemical transistor, an analog of the traditional transistor used to amplify and/or switch electronic signals. Finally, we demonstrate the use of the OEIP in a new "machine-to-brain" interface by modulating brainstem responses in vivo. This review highlights the potential of communication interfaces based on conjugated polymers in generating complex, high-resolution, signal patterns to control cell physiology. We foresee widespread applications for these devices in biomedical research and in future medical devices within multiple therapeutic areas. This article is part of a Special Issue entitled Organic Bioelectronics-Novel Applications in Biomedicine. Copyright © 2012 Elsevier B.V. All rights reserved.

Thermionic gas switch

DOEpatents

Hatch, George L.; Brummond, William A.; Barrus, Donald M.

1986-01-01

A temperature responsive thermionic gas switch having folded electron emitting surfaces. An ionizable gas is located between the emitter and an interior surface of a collector, coaxial with the emitter. In response to the temperature exceeding a predetermined level, sufficient electrons are derived from the emitter to cause the gas in the gap between the emitter and collector to become ionized, whereby a very large increase in current in the gap occurs. Due to the folded emitter surface area of the switch, increasing the "on/off" current ratio and adjusting the "on" current capacity is accomplished.

Picoampere Resistive Switching Characteristics Realized with Vertically Contacted Carbon Nanotube Atomic Force Microscope Probe

NASA Astrophysics Data System (ADS)

Nakano, Haruhisa; Takahashi, Makoto; Sato, Motonobu; Kotsugi, Masato; Ohkochi, Takuo; Muro, Takayuki; Nihei, Mizuhisa; Yokoyama, Naoki

2013-11-01

The resistive switching characteristics of a TiO2/Ti structure have been investigated using a conductive atomic force microscopy (AFM) system with 5-nm-diameter carbon nanotube (CNT) probes. The resistive switching showed bipolar resistive random access memory (ReRAM) behaviors with extremely low switching currents in the order of Picoamperes when voltages were applied. From transmission electron microscopy (TEM) observation, we confirmed that filament-like nanocrystals, having a diameter of about 10 nm, existed in TiO2 films at resistive switching areas after not only set operation but also reset operation. Moreover, photoemission electron microscopy (PEEM) analysis showed that the anatase-type TiO2 structure did not change after set and reset operations. From these results, we suggested that the Picoampere resistive switching occurred at the interface between the TiO2 dielectric and conductive nanocrystal without any structural changes in the TiO2 film and nanocrystal. The resistive switching mechanism we suggested is highly promising to realize extremely low-power-consumption ReRAMs with vertically contacted CNT electrodes.

Electro-optic Q-switch

NASA Technical Reports Server (NTRS)

Zou, Yingyin (Inventor); Chen, Qiushui (Inventor); Zhang, Run (Inventor); Jiang, Hua (Inventor)

2006-01-01

An electro-optic Q-switch for generating sequence of laser pulses was disclosed. The Q-switch comprises a quadratic electro-optic material and is connected with an electronic unit generating a radio frequency wave with positive and negative pulses alternatively. The Q-switch is controlled by the radio frequency wave in such a way that laser pulse is generated when the radio frequency wave changes its polarity.

Gamma-ray irradiation of ohmic MEMS switches

NASA Astrophysics Data System (ADS)

Maciel, John J.; Lampen, James L.; Taylor, Edward W.

2012-10-01

Radio Frequency (RF) Microelectromechanical System (MEMS) switches are becoming important building blocks for a variety of military and commercial applications including switch matrices, phase shifters, electronically scanned antennas, switched filters, Automatic Test Equipment, instrumentation, cell phones and smart antennas. Low power consumption, large ratio of off-impedance to on-impedance, extreme linearity, low mass, small volume and the ability to be integrated with other electronics makes MEMS switches an attractive alternative to other mechanical and solid-state switches for a variety of space applications. Radant MEMS, Inc. has developed an electrostatically actuated broadband ohmic microswitch that has applications from DC through the microwave region. Despite the extensive earth based testing, little is known about the performance and reliability of these devices in space environments. To help fill this void, we have irradiated our commercial-off-the-shelf SPST, DC to 40 GHz MEMS switches with gamma-rays as an initial step to assessing static impact on RF performance. Results of Co-60 gamma-ray irradiation of the MEMS switches at photon energies ≥ 1.0 MeV to a total dose of ~ 118 krad(Si) did not show a statistically significant post-irradiation change in measured broadband, RF insertion loss, insertion phase, return loss and isolation.

Anti-parallel polarization switching in a triglycine sulfate organic ferroelectric insulator: The role of surface charges

NASA Astrophysics Data System (ADS)

Ma, He; Wu, Zhuangchun; Peng, Dongwen; Wang, Yaojin; Wang, Yiping; Yang, Ying; Yuan, Guoliang

2018-04-01

Four consecutive ferroelectric polarization switchings and an abnormal ring-like domain pattern can be introduced by a single tip bias of a piezoresponse force microscope in the (010) triglycine sulfate (TGS) crystal. The external electric field anti-parallel to the original polarization induces the first polarization switching; however, the surface charges of TGS can move toward the tip location and induce the second polarization switching once the tip bias is removed. The two switchings allow a ring-like pattern composed of the central domain with downward polarization and the outer domain with upward polarization. Once the two domains disappear gradually as a result of depolarization, the other two polarization switchings occur one by one at the TGS where the tip contacts. However, the backswitching phenomenon does not occur when the external electric field is parallel to the original polarization. These results can be explained according to the surface charges instead of the charges injected inside.

Research on the electromagnetic radiation characteristics of the gas main switch of a capacitive intense electron-beam accelerator

NASA Astrophysics Data System (ADS)

Qiu, Yongfeng; Liu, Jinliang; Yang, Jianhua; Cheng, Xinbing; Li, Guolin

2017-11-01

Strong electromagnetic fields are radiated during the operation of the intense electron-beam accelerator (IEBA), which may lead to the nearby electronic devices out of order. In this paper, the research on the electromagnetic radiation characteristic of the gas main switch of a capacitive IEBA is carried out by the methods of theory analysis and experiment investigation. It is obtained that the gas main switch is the dominating radiation resource. In the absence of electromagnetic shielding for the gas main switch, when the pulse forming line of the IEBA is charged to 700 kV, the radiation field with amplitude of 3280 V/m, dominant frequency of 84 MHz and high frequency 100 MHz is obtained at a distance of 10 meters away from the gas main switch. The experimental results of the radiation field agree with the theoretical calculations. We analyze the achievements of several research groups and find that there is a relationship between the rise time (T) of the transient current of the gas main switch and the dominant frequency (F) of the radiation field, namely, F*T=1. Contrast experiment is carried out with a metal shield cover for the gas main switch. Experimental results show that for the shielded setup the radiation field reduces to 115 V/m, the dominant frequency increases to 86.5 MHz at a distance of 10 away meters from the gas main switch. These conclusions are beneficial for further research on the electromagnetic radiation and protection of the IEBA.

Switching Matrix For Optical Signals

NASA Technical Reports Server (NTRS)

Grove, Charles H.

1990-01-01

Proposed matrix of electronically controlled shutters switches signals in optical fibers between multiple input and output channels. Size, weight, and power consumption reduced. Device serves as building block for small, low-power, broad-band television- and data-signal-switching systems providing high isolation between nominally disconnected channels.

Comparison of generic-to-brand switchback patterns for generic and authorized generic drugs

PubMed Central

Hansen, Richard A.; Qian, Jingjing; Berg, Richard; Linneman, James; Seoane-Vazquez, Enrique; Dutcher, Sarah K.; Raofi, Saeid; Page, C. David; Peissig, Peggy

2018-01-01

Background While generic drugs are therapeutically equivalent to brand drugs, some patients and healthcare providers remain uncertain about whether they produce identical outcomes. Authorized generics, which are identical in formulation to corresponding brand drugs but marketed as a generic, provide a unique post-marketing opportunity to study whether utilization patterns are influenced by perceptions of generic drugs. Objectives To compare generic-to-brand switchback rates between generics and authorized generics. Methods A retrospective cohort study was conducted using claims and electronic health records data from a regional U.S. healthcare system. Ten drugs with authorized generics and generics marketed between 1999 and 2014 were evaluated. Eligible adult patients received a brand drug during the 6 months preceding generic entry, and then switched to a generic or authorized generic. Patients in this cohort were followed for up to 30 months from the index switch date to evaluate occurrence of generic-to-brand switchbacks. Switchback rates were compared between patients on authorized generics versus generics using Kaplan-Meier curves and Cox proportional hazards models, controlling for individual drug effects, age, sex, Charlson comorbidity score, pre-index drug use characteristics, and pre-index healthcare utilization. Results Among 5,542 unique patients that switched from brand-to-generic or brand-to-authorized generic, 264 (4.8%) switched back to the brand drug. Overall switchback rates were similar for authorized generics compared with generics (HR=0.86; 95% CI 0.65-1.15). The likelihood of switchback was higher for alendronate (HR=1.64; 95% CI 1.20-2.23) and simvastatin (HR=1.81; 95% CI 1.30-2.54) and lower for amlodipine (HR=0.27; 95% CI 0.17-0.42) compared with other drugs in the cohort. Conclusions Overall switchback rates were similar between authorized generic and generic drug users, indirectly supporting similar efficacy and tolerability profiles for brand and generic drugs. Reasons for differences in switchback rates among specific products need to be further explored. PMID:28152215

Q-switched all-solid-state lasers and application in processing of thin-film solar cell

NASA Astrophysics Data System (ADS)

Liu, Liangqing; Wang, Feng

2009-08-01

Societal pressure to renewable clean energy is increasing which is expected to be used as part of an overall strategy to address global warming and oil crisis. Photovoltaic energy conversion devices are on a rapidly accelerating growth path driven by government, of which the costs and prices lower continuously. The next generation thin-film devices are considered to be more efficiency and greatly reduced silicon consumption, resulting in dramatically lower per unit fabrication costs. A key aspect of these devices is patterning large panels to create a monolithic array of series-interconnected cells to form a low current, high voltage module. This patterning is accomplished in three critical scribing processes called P1, P2, and P3. All-solid-state Q-switched lasers are the technology of choice for these processes, due to their advantages of compact configuration, high peak-value power, high repeat rate, excellent beam quality and stability, delivering the desired combination of high throughput and narrow, clean scribes. The end pumped all-solid-state lasers could achieve 1064nm IR resources with pulse width of nanoseconds adopting acoustic-optics Q-switch, shorter than 20ns. The repeat rate is up to 100kHz and the beam quality is close to diffraction limit. Based on this, 532nm green lasers, 355nm UV lasers and 266nm DUV lasers could be carried out through nonlinear frequency conversion. Different wave length lasers are chose to process selective materials. For example, 8-15 W IR lasers are used to scribe the TCO film (P1); 1-5 W green lasers are suitable for scribing the active semiconductor layers (P2) and the back contact layers (P3). Our company, Wuhan Lingyun Photo-electronic System Co. Ltd, has developed 20W IR and 5W green end-pumped Q-switched all-solid-state lasers for thin-film solar industry. Operating in high repeat rates, the speed of processing is up to 2.0 m/s.

High Peak Power Test and Evaluation of S-band Waveguide Switches

NASA Astrophysics Data System (ADS)

Nassiri, A.; Grelick, A.; Kustom, R. L.; White, M.

1997-05-01

The injector and source of particles for the Advanced Photon Source is a 2856-MHz S-band electron-positron linear accelerator (linac) which produces electrons with energies up to 650 MeV or positrons with energies up to 450 MeV. To improve the linac rf system availability, an additional modulator-klystron subsystem is being constructed to provide a switchable hot spare unit for each of the five exsisting S-band transmitters. The switching of the transmitters will require the use of SF6-pressurized S-band waveguide switches at a peak operating power of 35 MW. Such rf switches have been successfully operated at other accelerator facilities but at lower peak powers. A test stand has been set up at the Stanford Linear Accelerator Center (SLAC) Klystron Factory to conduct tests comparing the power handling characteristics of two WR-284 and one WR-340 switches. Test results are presented and their implications for the design of the switching system are discussed.

Inter-Sentential Patterns of Code-Switching: A Gender-Based Investigation of Male and Female EFL Teachers

ERIC Educational Resources Information Center

Gulzar, Malik Ajmal; Farooq, Muhammad Umar; Umer, Muhammad

2013-01-01

This article has sought to contribute to discussions concerning the value of inter-sentential patterns of code-switching (henceforth ISPCS) particularly in the context of EFL classrooms. Through a detailed analysis of recorded data produced in that context, distinctive features in the discourse were discerned which were associated with males' and…

Anode initiated surface flashover switch

DOEpatents

Brainard, John P.; Koss, Robert J.

2003-04-29

A high voltage surface flashover switch has a pair of electrodes spaced by an insulator. A high voltage is applied to an anode, which is smaller than the opposing, grounded, cathode. When a controllable source of electrons near the cathode is energized, the electrons are attracted to the anode where they reflect to the insulator and initiate anode to cathode breakdown.

Compact self-powered synchronous energy extraction circuit design with enhanced performance

NASA Astrophysics Data System (ADS)

Liu, Weiqun; Zhao, Caiyou; Badel, Adrien; Formosa, Fabien; Zhu, Qiao; Hu, Guangdi

2018-04-01

Synchronous switching circuit is viewed as an effective solution of enhancing the generator’s performance and providing better adaptability for load variations. A critical issue for these synchronous switching circuits is the self-powered realization. In contrast with other methods, the electronic breaker possesses the advantage of simplicity and reliability. However, beside the energy consumption of the electronic breakers, the parasitic capacitance decreases the available piezoelectric voltage. In this technical note, a new compact design of the self-powered switching circuit using electronic breaker is proposed. The envelope diodes are excluded and only a single envelope capacitor is used. The parasitic capacitance is reduced to half with boosted performance while the components are reduced with cost saved.

Sales forecasting newspaper with ARIMA: A case study

NASA Astrophysics Data System (ADS)

Permatasari, Carina Intan; Sutopo, Wahyudi; Hisjam, Muh.

2018-02-01

People are beginning to switch to using digital media for their daily activities, including changes in newspaper reading patterns to electronic news. In uncertainty trend, the customers of printed newspaper also have switched to electronic news. It has some negative effects on the printed newspaper demand, where there is often an inaccuracy of supply with demand which means that many newspapers are returned. The aim of this paper is to predict printed newspaper demand as accurately as possible to minimize the number of returns, to keep off the missed sales and to restrain the oversupply. The autoregressive integrated moving average (ARIMA) models were adopted to predict the right number of newspapers for a real case study of a newspaper company in Surakarta. The model parameters were found using maximum likelihood method. Then, the software Eviews 9 were utilized to forecasting any particular variables in the newspaper industry. This paper finally presents the appropriate of modeling and sales forecasting newspaper based on the output of the ARIMA models. In particular, it can be recommended to use ARIMA (1, 1, 0) model in predicting the number of newspapers. ARIMA (1, 1, 0) model was chosen from three different models that it provides the smallest value of the mean absolute percentage error (MAPE).

NASA Tech Briefs, October 2007

NASA Technical Reports Server (NTRS)

2007-01-01

Topics covered include; Wirelessly Interrogated Position or Displacement Sensors; Ka-Band Radar Terminal Descent Sensor; Metal/Metal Oxide Differential Electrode pH Sensors; Improved Sensing Coils for SQUIDs; Inductive Linear-Position Sensor/Limit-Sensor Units; Hilbert-Curve Fractal Antenna With Radiation- Pattern Diversity; Single-Camera Panoramic-Imaging Systems; Interface Electronic Circuitry for an Electronic Tongue; Inexpensive Clock for Displaying Planetary or Sidereal Time; Efficient Switching Arrangement for (N + 1)/N Redundancy; Lightweight Reflectarray Antenna for 7.115 and 32 GHz; Opto-Electronic Oscillator Using Suppressed Phase Modulation; Alternative Controller for a Fiber-Optic Switch; Strong, Lightweight, Porous Materials; Nanowicks; Lightweight Thermal Protection System for Atmospheric Entry; Rapid and Quiet Drill; Hydrogen Peroxide Concentrator; MMIC Amplifiers for 90 to 130 GHz; Robot Would Climb Steep Terrain; Measuring Dynamic Transfer Functions of Cavitating Pumps; Advanced Resistive Exercise Device; Rapid Engineering of Three-Dimensional, Multicellular Tissues With Polymeric Scaffolds; Resonant Tunneling Spin Pump; Enhancing Spin Filters by Use of Bulk Inversion Asymmetry; Optical Magnetometer Incorporating Photonic Crystals; WGM-Resonator/Tapered-Waveguide White-Light Sensor Optics; Raman-Suppressing Coupling for Optical Parametric Oscillator; CO2-Reduction Primary Cell for Use on Venus; Cold Atom Source Containing Multiple Magneto- Optical Traps; POD Model Reconstruction for Gray-Box Fault Detection; System for Estimating Horizontal Velocity During Descent; Software Framework for Peer Data-Management Services; Autogen Version 2.0; Tracking-Data-Conversion Tool; NASA Enterprise Visual Analysis; Advanced Reference Counting Pointers for Better Performance; C Namelist Facility; and Efficient Mosaicking of Spitzer Space Telescope Images.

Quantum ballistic transport by interacting two-electron states in quasi-one-dimensional channels

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

Huang, Danhong; Center for High Technology Materials, University of New Mexico, 1313 Goddard St SE, Albuquerque, New Mexico 87106; Gumbs, Godfrey

2015-11-15

For quantum ballistic transport of electrons through a short conduction channel, the role of Coulomb interaction may significantly modify the energy levels of two-electron states at low temperatures as the channel becomes wide. In this regime, the Coulomb effect on the two-electron states is calculated and found to lead to four split energy levels, including two anticrossing-level and two crossing-level states. Moreover, due to the interplay of anticrossing and crossing effects, our calculations reveal that the ground two-electron state will switch from one anticrossing state (strong confinement) to a crossing state (intermediate confinement) as the channel width gradually increases andmore » then back to the original anticrossing state (weak confinement) as the channel width becomes larger than a threshold value. This switching behavior leaves a footprint in the ballistic conductance as well as in the diffusion thermoelectric power of electrons. Such a switching is related to the triple spin degeneracy as well as to the Coulomb repulsion in the central region of the channel, which separates two electrons away and pushes them to different channel edges. The conductance reoccurrence region expands from the weak to the intermediate confinement regime with increasing electron density.« less

Self-assembled phase-change nanowire for nonvolatile electronic memory

NASA Astrophysics Data System (ADS)

Jung, Yeonwoong

One of the most important subjects in nanosciences is to identify and exploit the relationship between size and structural/physical properties of materials and to explore novel material properties at a small-length scale. Scale-down of materials is not only advantageous in realizing miniaturized devices but nanometer-sized materials often exhibit intriguing physical/chemical properties that greatly differ from their bulk counterparts. This dissertation studies self-assembled phase-change nanowires for future nonvolatile electronic memories, mainly focusing on their size-dependent memory switching properties. Owing to the one-dimensional, unique geometry coupled with the small and tunable sizes, bottom-designed nanowires offer great opportunities in terms for both fundamental science and practical engineering perspectives, which would be difficult to realize in conventional top-down based approaches. We synthesized chalcogenide phase-change nanowires of different compositions and sizes, and studied their electronic memory switching owing to the structural change between crystalline and amorphous phases. In particular, we investigated nanowire size-dependent memory switching parameters, including writing current, power consumption, and data retention times, as well as studying composition-dependent electronic properties. The observed size and composition-dependent switching and recrystallization kinetics are explained based on the heat transport model and heterogeneous nucleation theories, which help to design phase-change materials with better properties. Moreover, we configured unconventional heterostructured phase-change nanowire memories and studied their multiple memory states in single nanowire devices. Finally, by combining in-situ/ex-situ electron microscopy techniques and electrical measurements, we characterized the structural states involved in electrically-driven phase-change in order to understand the atomistic mechanism that governs the electronic memory switching through phase-change.

Terahertz optoelectronics with surface plasmon polariton diode.

PubMed

Vinnakota, Raj K; Genov, Dentcho A

2014-05-09

The field of plasmonics has experience a renaissance in recent years by providing a large variety of new physical effects and applications. Surface plasmon polaritons, i.e. the collective electron oscillations at the interface of a metal/semiconductor and a dielectric, may bridge the gap between electronic and photonic devices, provided a fast switching mechanism is identified. Here, we demonstrate a surface plasmon-polariton diode (SPPD) an optoelectronic switch that can operate at exceedingly large signal modulation rates. The SPPD uses heavily doped p-n junction where surface plasmon polaritons propagate at the interface between n and p-type GaAs and can be switched by an external voltage. The devices can operate at transmission modulation higher than 98% and depending on the doping and applied voltage can achieve switching rates of up to 1 THz. The proposed switch is compatible with the current semiconductor fabrication techniques and could lead to nanoscale semiconductor-based optoelectronics.

Transient effects in beam-plasma interactions in a space simulation chamber stimulated by a fast pulse electron gun

NASA Technical Reports Server (NTRS)

Raitt, W. J.; Banks, P. M.; Denig, W. F.; Anderson, H. R.

1982-01-01

Interest in the interaction of electron beams with plasma generated by ionization caused by the primary electron beam was stimulated by the need to develop special vacuum tubes to operate in the kMHz frequency region. The experiments of Getty and Smullin (1963) indicated that the interaction of an energetic electron beam with its self-produced plasma resulted in the emission of wave energy over a wide range of frequencies associated with cyclotron and longitudinal plasma instabilities. This enhanced the thermal plasma density in the vicinity of the beam, and the term Beam-Plasma Discharge (BPD) was employed to described this phenomenon. The present investigation is concerned with some of the transient phenomena associated with wave emission during the beam switch-on and switch-off periods. Results are presented on the changes in electron energy spectra on a time scale of tens of milliseconds following beam switch-on. The results are discussed in terms of the beam plasma discharge phenomenon.

Electron holography on HfO2/HfO2-x bilayer structures with multilevel resistive switching properties

NASA Astrophysics Data System (ADS)

Niu, G.; Schubert, M. A.; Sharath, S. U.; Zaumseil, P.; Vogel, S.; Wenger, C.; Hildebrandt, E.; Bhupathi, S.; Perez, E.; Alff, L.; Lehmann, M.; Schroeder, T.; Niermann, T.

2017-05-01

Unveiling the physical nature of the oxygen-deficient conductive filaments (CFs) that are responsible for the resistive switching of the HfO2-based resistive random access memory (RRAM) devices represents a challenging task due to the oxygen vacancy related defect nature and nanometer size of the CFs. As a first important step to this goal, we demonstrate in this work direct visualization and a study of physico-chemical properties of oxygen-deficient amorphous HfO2-x by carrying out transmission electron microscopy electron holography as well as energy dispersive x-ray spectroscopy on HfO2/HfO2-x bilayer heterostructures, which are realized by reactive molecular beam epitaxy. Furthermore, compared to single layer devices, Pt/HfO2/HfO2-x /TiN bilayer devices show enhanced resistive switching characteristics with multilevel behavior, indicating their potential as electronic synapses in future neuromorphic computing applications.

A Locust Phase Change Model with Multiple Switching States and Random Perturbation

NASA Astrophysics Data System (ADS)

Xiang, Changcheng; Tang, Sanyi; Cheke, Robert A.; Qin, Wenjie

2016-12-01

Insects such as locusts and some moths can transform from a solitarious phase when they remain in loose populations and a gregarious phase, when they may swarm. Therefore, the key to effective management of outbreaks of species such as the desert locust Schistocercagregaria is early detection of when they are in the threshold state between the two phases, followed by timely control of their hopper stages before they fledge because the control of flying adult swarms is costly and often ineffective. Definitions of gregarization thresholds should assist preventive control measures and avoid treatment of areas that might not lead to gregarization. In order to better understand the effects of the threshold density which represents the gregarization threshold on the outbreak of a locust population, we developed a model of a discrete switching system. The proposed model allows us to address: (1) How frequently switching occurs from solitarious to gregarious phases and vice versa; (2) When do stable switching transients occur, the existence of which indicate that solutions with larger amplitudes can switch to a stable attractor with a value less than the switching threshold density?; and (3) How does random perturbation influence the switching pattern? Our results show that both subsystems have refuge equilibrium points, outbreak equilibrium points and bistable equilibria. Further, the outbreak equilibrium points and bistable equilibria can coexist for a wide range of parameters and can switch from one to another. This type of switching is sensitive to the intrinsic growth rate and the initial values of the locust population, and may result in locust population outbreaks and phase switching once a small perturbation occurs. Moreover, the simulation results indicate that the switching transient patterns become identical after some generations, suggesting that the evolving process of the perturbation system is not related to the initial value after some fixed number of generations for the same stochastic processes. However, the switching frequency and outbreak patterns can be significantly affected by the intensity of noise and the intrinsic growth rate of the locust population.

Atomic switch networks—nanoarchitectonic design of a complex system for natural computing

NASA Astrophysics Data System (ADS)

Demis, E. C.; Aguilera, R.; Sillin, H. O.; Scharnhorst, K.; Sandouk, E. J.; Aono, M.; Stieg, A. Z.; Gimzewski, J. K.

2015-05-01

Self-organized complex systems are ubiquitous in nature, and the structural complexity of these natural systems can be used as a model to design new classes of functional nanotechnology based on highly interconnected networks of interacting units. Conventional fabrication methods for electronic computing devices are subject to known scaling limits, confining the diversity of possible architectures. This work explores methods of fabricating a self-organized complex device known as an atomic switch network and discusses its potential utility in computing. Through a merger of top-down and bottom-up techniques guided by mathematical and nanoarchitectonic design principles, we have produced functional devices comprising nanoscale elements whose intrinsic nonlinear dynamics and memorization capabilities produce robust patterns of distributed activity and a capacity for nonlinear transformation of input signals when configured in the appropriate network architecture. Their operational characteristics represent a unique potential for hardware implementation of natural computation, specifically in the area of reservoir computing—a burgeoning field that investigates the computational aptitude of complex biologically inspired systems.

RF MEMS and Their Applications in NASA's Space Communication Systems

NASA Technical Reports Server (NTRS)

Williams, W. Daniel; Ponchak, George E.; Simons, Rainee N.; Zaman, Afroz; Kory, Carol; Wintucky, Edwin; Wilson, Jeffrey D.; Scardelletti, Maximilian; Lee, Richard; Nguyen, Hung

2001-01-01

Radio frequency (RF) and microwave communication systems rely on frequency, amplitude, and phase control circuits to efficiently use the available spectrum. Phase control circuits are required for electronically scanning phase array antennas that enable radiation pattern shaping, scanning, and hopping. Two types of phase shifters, which are the phase control circuits, are most often used. The first is comprised of two circuits with different phase characteristics such as two transmission lines of different lengths or a high pass and low pass filter and a switch that directs the RF power through one of the two circuits. Alternatively, a variable capacitor, or varactor, is used to change the effective electrical path length of a transmission line, which changes the phase characteristics. Filter banks are required for the diplexer at the front end of wide band communication satellites. These filters greatly increase the size and mass of the RF/microwave systems, but smaller diplexers may be made with a low loss varactor or a group of capacitors, a switch and an inductor.

Atomic switch networks-nanoarchitectonic design of a complex system for natural computing.

PubMed

Demis, E C; Aguilera, R; Sillin, H O; Scharnhorst, K; Sandouk, E J; Aono, M; Stieg, A Z; Gimzewski, J K

2015-05-22

Self-organized complex systems are ubiquitous in nature, and the structural complexity of these natural systems can be used as a model to design new classes of functional nanotechnology based on highly interconnected networks of interacting units. Conventional fabrication methods for electronic computing devices are subject to known scaling limits, confining the diversity of possible architectures. This work explores methods of fabricating a self-organized complex device known as an atomic switch network and discusses its potential utility in computing. Through a merger of top-down and bottom-up techniques guided by mathematical and nanoarchitectonic design principles, we have produced functional devices comprising nanoscale elements whose intrinsic nonlinear dynamics and memorization capabilities produce robust patterns of distributed activity and a capacity for nonlinear transformation of input signals when configured in the appropriate network architecture. Their operational characteristics represent a unique potential for hardware implementation of natural computation, specifically in the area of reservoir computing-a burgeoning field that investigates the computational aptitude of complex biologically inspired systems.

Cascades of alternating pitchfork and flip bifurcations in H-bridge inverters

NASA Astrophysics Data System (ADS)

Avrutin, Viktor; Zhusubaliyev, Zhanybai T.; Mosekilde, Erik

2017-04-01

Power electronic DC/AC converters (inverters) play an important role in modern power engineering. These systems are also of considerable theoretical interest because their dynamics is influenced by the presence of two vastly different forcing frequencies. As a consequence, inverter systems may be modeled in terms of piecewise smooth maps with an extremely high number of switching manifolds. We have recently shown that models of this type can demonstrate a complicated bifurcation structure associated with the occurrence of border collisions. Considering the example of a PWM H-bridge single-phase inverter, the present paper discusses a number of unusual phenomena that can occur in piecewise smooth maps with a very large number of switching manifolds. We show in particular how smooth (pitchfork and flip) bifurcations may form a macroscopic pattern that stretches across the overall bifurcation structure. We explain the observed bifurcation phenomena, show under which conditions they occur, and describe them quantitatively by means of an analytic approximation.

Memory switches based on metal oxide thin films

NASA Technical Reports Server (NTRS)

Ramesham, Rajeshuni (Inventor); Thakoor, Anilkumar P. (Inventor); Lambe, John J. (Inventor)

1990-01-01

MnO.sub.2-x thin films (12) exhibit irreversible memory switching (28) with an OFF/ON resistance ratio of at least about 10.sup.3 and the tailorability of ON state (20) resistance. Such films are potentially extremely useful as a connection element in a variety of microelectronic circuits and arrays (24). Such films provide a pre-tailored, finite, non-volatile resistive element at a desired place in an electric circuit, which can be electrically turned OFF (22) or disconnected as desired, by application of an electrical pulse. Microswitch structures (10) constitute the thin film element, contacted by a pair of separate electrodes (16a, 16b) and have a finite, pre-selected ON resistance which is ideally suited, for example, as a programmable binary synaptic connection for electronic implementation of neural network architectures. The MnO.sub.2-x microswitch is non-volatile, patternable, insensitive to ultraviolet light, and adherent to a variety of insulating substrates (14), such as glass and silicon dioxide-coated silicon substrates.

Enhancement of polar anchoring strength in a graphene-nematic suspension and its effect on nematic electro-optic switching

NASA Astrophysics Data System (ADS)

Basu, Rajratan

2017-07-01

A small quantity of monolayer graphene flakes is doped in a nematic liquid crystal (LC), and the effective polar anchoring strength coefficient between the LC and the alignment substrate is found to increase by an order of magnitude. The hexagonal pattern of graphene can interact with the LC's benzene rings via π -π electron stacking, enabling the LC to anchor to the graphene surface homogeneously (i.e., planar anchoring). When the LC cell is filled with the graphene-doped LC, some graphene flakes are preferentially attached to the alignment layer and modify the substrate's anchoring property. These spontaneously deposited graphene flakes promote planar anchoring at the substrate and the polar anchoring energy at alignment layer is enhanced significantly. The enhanced anchoring energy is found to impact favorably on the electro-optic response of the LC. Additional studies reveal that the nematic electro-optic switching is significantly faster in the LC-graphene hybrid than that of the pure LC.

Cognitive performance in healthy older adults relates to spontaneous switching between states of functional connectivity during rest.

PubMed

Cabral, Joana; Vidaurre, Diego; Marques, Paulo; Magalhães, Ricardo; Silva Moreira, Pedro; Miguel Soares, José; Deco, Gustavo; Sousa, Nuno; Kringelbach, Morten L

2017-07-11

Growing evidence has shown that brain activity at rest slowly wanders through a repertoire of different states, where whole-brain functional connectivity (FC) temporarily settles into distinct FC patterns. Nevertheless, the functional role of resting-state activity remains unclear. Here, we investigate how the switching behavior of resting-state FC relates with cognitive performance in healthy older adults. We analyse resting-state fMRI data from 98 healthy adults previously categorized as being among the best or among the worst performers in a cohort study of >1000 subjects aged 50+ who underwent neuropsychological assessment. We use a novel approach focusing on the dominant FC pattern captured by the leading eigenvector of dynamic FC matrices. Recurrent FC patterns - or states - are detected and characterized in terms of lifetime, probability of occurrence and switching profiles. We find that poorer cognitive performance is associated with weaker FC temporal similarity together with altered switching between FC states. These results provide new evidence linking the switching dynamics of FC during rest with cognitive performance in later life, reinforcing the functional role of resting-state activity for effective cognitive processing.

Three-dimensional resistivity and switching between correlated electronic states in 1T-TaS2

NASA Astrophysics Data System (ADS)

Svetin, Damjan; Vaskivskyi, Igor; Brazovskii, Serguei; Mihailovic, Dragan

2017-04-01

Recent demonstrations of controlled switching between different ordered macroscopic states by impulsive electromagnetic perturbations in complex materials have opened some fundamental questions on the mechanisms responsible for such remarkable behavior. Here we experimentally address the question of whether two-dimensional (2D) Mott physics can be responsible for unusual switching between states of different electronic order in the layered dichalcogenide 1T-TaS2, or it is a result of subtle inter-layer “orbitronic” re-ordering of its stacking structure. We report on in-plane (IP) and out-of-plane (OP) resistance switching by current-pulse injection at low temperatures. Elucidating the controversial theoretical predictions, we also report on measurements of the anisotropy of the electrical resistivity below room temperature. From the T-dependence of ρ⊥ and ρ||, we surmise that the resistivity is more consistent with collective motion than single particle diffusive or band-like transport. The relaxation dynamics of the metastable state for both IP and OP electron transport are seemingly governed by the same mesoscopic quantum re-ordering process. We conclude that 1T-TaS2 shows resistance switching arising from an interplay of both IP and OP correlations.

Solvation and Evolution Dynamics of an Excess Electron in Supercritical CO2

NASA Astrophysics Data System (ADS)

Wang, Zhiping; Liu, Jinxiang; Zhang, Meng; Cukier, Robert I.; Bu, Yuxiang

2012-05-01

We present an ab initio molecular dynamics simulation of the dynamics of an excess electron solvated in supercritical CO2. The excess electron can exist in three types of states: CO2-core localized, dual-core localized, and diffuse states. All these states undergo continuous state conversions via a combination of long lasting breathing oscillations and core switching, as also characterized by highly cooperative oscillations of the excess electron volume and vertical detachment energy. All of these oscillations exhibit a strong correlation with the electron-impacted bending vibration of the core CO2, and the core-switching is controlled by thermal fluctuations.

Concept and design of a beam blanker with integrated photoconductive switch for ultrafast electron microscopy.

PubMed

Weppelman, I G C; Moerland, R J; Hoogenboom, J P; Kruit, P

2018-01-01

We present a new method to create ultrashort electron pulses by integrating a photoconductive switch with an electrostatic deflector. This paper discusses the feasibility of such a system by analytical and numerical calculations. We argue that ultrafast electron pulses can be achieved for micrometer scale dimensions of the blanker, which are feasible with MEMS-based fabrication technology. According to basic models, the design presented in this paper is capable of generating 100 fs electron pulses with spatial resolutions of less than 10 nm. Our concept for an ultrafast beam blanker (UFB) may provide an attractive alternative to perform ultrafast electron microscopy, as it does not require modification of the microscope nor realignment between DC and pulsed mode of operation. Moreover, only low laser pulse energies are required. Due to its small dimensions the UFB can be inserted in the beam line of a commercial microscope via standard entry ports for blankers or variable apertures. The use of a photoconductive switch ensures minimal jitter between laser and electron pulses. Copyright © 2017 Elsevier B.V. All rights reserved.

Electron emission from ferroelectrics - a review

NASA Astrophysics Data System (ADS)

Riege, H.

1994-02-01

The strong pulsed emission of electrons from the surface of ferroelectric (FE) materials was discovered at CERN in 1987. Since then many aspects and properties of the method of generation and propagation of electron beams from FE have been studied experimentally. The method is based on macroscopic charge separation and self-emission of electrons under the influence of their own space-charge fields. Hence, this type of emission is not limited by the Langmuir-Child law as are conventional emission methods. Charge separation and electron emission can be achieved by rapid switching of the spontaneous, ferroelectric polarization. Polarization switching may be induced by application of electrical-field or mechanical-pressure pulses, as well as by thermal heating or laser illumination of the ferroelectric emitter. At higher emission intensities plasma formation assists the FE emission and leads to a strong growth of emitted current amplitude, which is no longer limited by the FE material and the surface properties. The most attractive features of FE emission are robustness and ease of manipulation of the emitter cathodes which can be transported through atmospheric air and used without any problems in vacuum, low-pressure gas or plasma environments. Large-area arrangements of multiple emitters, switched in interleaved mode, can produce electron beams of any shape, current amplitude or time structure. The successful application of FE emission in accelerator technology has been demonstrated experimentally in several cases, e.g. for triggering high-power gas switches, for photocathodes in electron guns, and for electron-beam generators intended to generate, neutralize and enhance ion beams in ion sources and ion linacs. Other applications can be envisaged in microwave power generators and in the fields of electronics and vacuum microelectronics.

Parsing the roles of the frontal lobes and basal ganglia in task control using multivoxel pattern analysis

PubMed Central

Kehagia, Angie A.; Ye, Rong; Joyce, Dan W.; Doyle, Orla M.; Rowe, James B.; Robbins, Trevor W.

2017-01-01

Cognitive control has traditionally been associated with the prefrontal cortex, based on observations of deficits in patients with frontal lesions. However, evidence from patients with Parkinson’s disease (PD) indicates that subcortical regions also contribute to control under certain conditions. We scanned 17 healthy volunteers while they performed a task switching paradigm that previously dissociated performance deficits arising from frontal lesions in comparison with PD, as a function of the abstraction of the rules that are switched. From a multivoxel pattern analysis by Gaussian Process Classification (GPC), we then estimated the forward (generative) model to infer regional patterns of activity that predict Switch / Repeat behaviour between rule conditions. At 1000 permutations, Switch / Repeat classification accuracy for concrete rules was significant in the basal ganglia, but at chance in the frontal lobe. The inverse pattern was obtained for abstract rules, whereby the conditions were successfully discriminated in the frontal lobe but not in the basal ganglia. This double dissociation highlights the difference between cortical and subcortical contributions to cognitive control and demonstrates the utility of multivariate approaches in investigations of functions that rely on distributed and overlapping neural substrates. PMID:28387585

Constraining Data Mining with Physical Models: Voltage- and Oxygen Pressure-Dependent Transport in Multiferroic Nanostructures

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

Strelcov, Evgheni; Belianinov, Alexei; Hsieh, Ying-Hui

Development of new generation electronic devices requires understanding and controlling the electronic transport in ferroic, magnetic, and optical materials, which is hampered by two factors. First, the complications of working at the nanoscale, where interfaces, grain boundaries, defects, and so forth, dictate the macroscopic characteristics. Second, the convolution of the response signals stemming from the fact that several physical processes may be activated simultaneously. Here, we present a method of solving these challenges via a combination of atomic force microscopy and data mining analysis techniques. Rational selection of the latter allows application of physical constraints and enables direct interpretation ofmore » the statistically significant behaviors in the framework of the chosen physical model, thus distilling physical meaning out of raw data. We demonstrate our approach with an example of deconvolution of complex transport behavior in a bismuth ferrite–cobalt ferrite nanocomposite in ambient and ultrahigh vacuum environments. Measured signal is apportioned into four electronic transport patterns, showing different dependence on partial oxygen and water vapor pressure. These patterns are described in terms of Ohmic conductance and Schottky emission models in the light of surface electrochemistry. Finally and furthermore, deep data analysis allows extraction of local dopant concentrations and barrier heights empowering our understanding of the underlying dynamic mechanisms of resistive switching.« less

Constraining Data Mining with Physical Models: Voltage- and Oxygen Pressure-Dependent Transport in Multiferroic Nanostructures

DOE PAGES

Strelcov, Evgheni; Belianinov, Alexei; Hsieh, Ying-Hui; ...

2015-08-27

Development of new generation electronic devices requires understanding and controlling the electronic transport in ferroic, magnetic, and optical materials, which is hampered by two factors. First, the complications of working at the nanoscale, where interfaces, grain boundaries, defects, and so forth, dictate the macroscopic characteristics. Second, the convolution of the response signals stemming from the fact that several physical processes may be activated simultaneously. Here, we present a method of solving these challenges via a combination of atomic force microscopy and data mining analysis techniques. Rational selection of the latter allows application of physical constraints and enables direct interpretation ofmore » the statistically significant behaviors in the framework of the chosen physical model, thus distilling physical meaning out of raw data. We demonstrate our approach with an example of deconvolution of complex transport behavior in a bismuth ferrite–cobalt ferrite nanocomposite in ambient and ultrahigh vacuum environments. Measured signal is apportioned into four electronic transport patterns, showing different dependence on partial oxygen and water vapor pressure. These patterns are described in terms of Ohmic conductance and Schottky emission models in the light of surface electrochemistry. Finally and furthermore, deep data analysis allows extraction of local dopant concentrations and barrier heights empowering our understanding of the underlying dynamic mechanisms of resistive switching.« less

A single electron nanomechanical Y-switch.

PubMed

Kim, Chulki; Kim, Hyun-Seok; Prada, Marta; Blick, Robert H

2014-08-07

We demonstrate current switching in the frequency domain using a nanomechanical shuttle with three terminals operating at room temperature. The shuttle consists of a metallic island on top of a Si nanopillar forming the Y-junction. A flexural mode of the nanopillar is excited by applying an external bias to one of the contacts, allowing electrons to be shuttled across the oscillating island.

67. Building 102, view of electronic switching amplifier (in retracted ...

Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

67. Building 102, view of electronic switching amplifier (in retracted or open position) with video monitor mounted at top to monitor performance and condition of system in oil bath. - Clear Air Force Station, Ballistic Missile Early Warning System Site II, One mile west of mile marker 293.5 on Parks Highway, 5 miles southwest of Anderson, Anderson, Denali Borough, AK

Programmable synaptic chip for electronic neural networks

NASA Technical Reports Server (NTRS)

Moopenn, A.; Langenbacher, H.; Thakoor, A. P.; Khanna, S. K.

1988-01-01

A binary synaptic matrix chip has been developed for electronic neural networks. The matrix chip contains a programmable 32X32 array of 'long channel' NMOSFET binary connection elements implemented in a 3-micron bulk CMOS process. Since the neurons are kept off-chip, the synaptic chip serves as a 'cascadable' building block for a multi-chip synaptic network as large as 512X512 in size. As an alternative to the programmable NMOSFET (long channel) connection elements, tailored thin film resistors are deposited, in series with FET switches, on some CMOS test chips, to obtain the weak synaptic connections. Although deposition and patterning of the resistors require additional processing steps, they promise substantial savings in silicon area. The performance of synaptic chip in a 32-neuron breadboard system in an associative memory test application is discussed.

Treatment patterns and low-density lipoprotein cholesterol (LDL-C) goal attainment among patients receiving high- or moderate-intensity statins.

PubMed

Fox, Kathleen M; Tai, Ming-Hui; Kostev, Karel; Hatz, Maximilian; Qian, Yi; Laufs, Ulrich

2018-05-01

European clinical guidelines recommend a low-density lipoprotein cholesterol (LDL-C) goal of < 70 mg/dL. Statin use varies and past studies suggest low rates of real-world goal attainment. This study describes LDL-C goal attainment among atherosclerotic CV disease (ASCVD) patients with various utilization patterns of moderate- or high-intensity statins in routine care. This retrospective cohort study used electronic medical records data from the QuintilesIMS® Disease Analyzer (> 2 million individuals annually) to identify ASCVD (coronary atherosclerosis, stable/unstable angina, myocardial infarction, ischemic stroke, transient ischemic attack, aneurysm, peripheral artery disease) patients on moderate-/high-intensity statin in Germany. Proportion of patients with LDL-C < 70 mg/dL was determined using the lowest LDL-C value for each patient (index) in 2012, 2013, and 2014, while on statin. Treatment patterns were assessed for patients with at least 1 year of post-index follow-up. Results were stratified by year and treatment pattern [no change, switch, dose up-/down-titration, discontinuation (≥ 90 day gap)]. In > 14,000 patients assessed in each year (mean age 71 years, 35% female, 8-12% taking high-intensity statins), approximately 80% had LDL-C ≥ 70 mg/dL. Treatment patterns were assessed for most (88-93%) patients. Approximately 79-81% of patients made no change to statin regimens, 1% switched statins, 14-16% discontinued; 1% of moderate-intensity patients up-titrated, and 3% of all patients down-titrated. LDL-C goal attainment in these treatment pattern groups was 20, 16-24, 17, 11-14, and 17-19%, respectively. Majority of ASCVD patients had LDL-C ≥ 70 mg/dL while on moderate-/high-intensity statins. Despite low LDL-C goal attainment, few patients changed their treatment regimens.

Performance, operational limits, of an Electronic Switching Spherical Array (ESSA) antenna

NASA Technical Reports Server (NTRS)

Stockton, R.

1979-01-01

The development of a microprocessor controller which provides multimode operational capability for the Electronic Switching Spherical Array (ESSA) Antenna is described. The best set of operating conditions were determined and the performance of an ESSA antenna was demonstrated in the following modes: (1) omni; (2) acquisition/track; (3) directive; and (4) multibeam. The control algorithms, software flow diagrams, and electronic circuitry were developed. The microprocessor and control electronics were built and interfaced with the antenna to carry out performance testing. The acquisition/track mode for users in the Tracking and Data Relay Satellite System is emphasized.

The modeling of an automotive electronic control system and the application of optimizing methods

NASA Astrophysics Data System (ADS)

Zhang, Yansheng; Yang, Zhigang; Zhang, Xiang

2005-12-01

Now, MATLAB/SIMULINK software is popularly used by automotive electronic control designers to develop automotive electronic control systems and perform numerical simulations. But they will face problems, such as value initialization in the "integrator" block, conversion among different data types, selection of "if" block and "switch" block, realization of the "if-clause" under multiple options and the auto-switching control, etc. Taking as an example the designing of an Automated Mechanical Transmission (AMT) system, this paper discusses some techniques and methods for modeling the automotive electronic control system with MATLAB/SIMULINK, offering designers some successful examples.

Immediate effects of modified landing pattern on a probabilistic tibial stress fracture model in runners.

PubMed

Chen, T L; An, W W; Chan, Z Y S; Au, I P H; Zhang, Z H; Cheung, R T H

2016-03-01

Tibial stress fracture is a common injury in runners. This condition has been associated with increased impact loading. Since vertical loading rates are related to the landing pattern, many heelstrike runners attempt to modify their footfalls for a lower risk of tibial stress fracture. Such effect of modified landing pattern remains unknown. This study examined the immediate effects of landing pattern modification on the probability of tibial stress fracture. Fourteen experienced heelstrike runners ran on an instrumented treadmill and they were given augmented feedback for landing pattern switch. We measured their running kinematics and kinetics during different landing patterns. Ankle joint contact force and peak tibial strains were estimated using computational models. We used an established mathematical model to determine the effect of landing pattern on stress fracture probability. Heelstrike runners experienced greater impact loading immediately after landing pattern switch (P<0.004). There was an increase in the longitudinal ankle joint contact force when they landed with forefoot (P=0.003). However, there was no significant difference in both peak tibial strains and the risk of tibial stress fracture in runners with different landing patterns (P>0.986). Immediate transitioning of the landing pattern in heelstrike runners may not offer timely protection against tibial stress fracture, despite a reduction of impact loading. Long-term effects of landing pattern switch remains unknown. Copyright © 2016 Elsevier Ltd. All rights reserved.

Magnetically Delayed Low-Pressure Gas Discharge Switching

DTIC Science & Technology

1993-06-01

the gap, minimizes this effect. It is this version of the low- pressure switch that we are presently studying. Our magnetically delayed low... pressure switch (MDLPS) test-stand was built primarily to support the long-pulse, relativistic klystron (RK) and free electron laser (FEL) work at... pressure switch and compared the performance with and without the saturable inductor. A comparison of typi- cal closure properties is shown in Fig

Conversion of Radio-Frequency Pulses to Continuous-Wave Sinusoids by Fast Switching and Narrowband Filtering

DTIC Science & Technology

2016-09-01

Switching and Narrowband Filtering by Gregory J Mazzaro, Andrew J Sherbondy, Kenneth I Ranney, and Kelly D Sherbondy...Switching and Narrowband Filtering by Gregory J Mazzaro, Andrew J Sherbondy, Kenneth I Ranney, and Kelly D Sherbondy Sensors and Electron Devices...08/2016 4. TITLE AND SUBTITLE Conversion of Radio-Frequency Pulses to Continuous-Wave Sinusoids by Fast Switching and Narrowband Filtering 5a

Common and Distinct Neural Mechanisms of Attentional Switching and Response Conflict

PubMed Central

Kim, Chobok; Johnson, Nathan F.; Gold, Brian T.

2012-01-01

The human capacities for overcoming prepotent actions and flexibly switching between tasks represent cornerstones of cognitive control. Functional neuroimaging has implicated a diverse set of brain regions contributing to each of these cognitive control processes. However, the extent to which attentional switching and response conflict draw on shared or distinct neural mechanisms remains unclear. The current study examined the neural correlates of response conflict and attentional switching using event-related functional magnetic resonance imaging (fMRI) and a fully randomized 2×2 design. We manipulated an arrow-word version of the Stroop task to measure conflict and switching in the context of a single task decision, in response to a common set of stimuli. Under these common conditions, both behavioral and imaging data showed significant main effects of conflict and switching but no interaction. However, conjunction analyses identified frontal regions involved in both switching and response conflict, including the dorsal anterior cingulate cortex (dACC) and left inferior frontal junction. In addition, connectivity analyses demonstrated task-dependent functional connectivity patterns between dACC and inferior temporal cortex for attentional switching and between dACC and posterior parietal cortex for response conflict. These results suggest that the brain makes use of shared frontal regions, but can dynamically modulate the connectivity patterns of some of those regions, to deal with attentional switching and response conflict. PMID:22750124

Common and distinct neural mechanisms of attentional switching and response conflict.

PubMed

Kim, Chobok; Johnson, Nathan F; Gold, Brian T

2012-08-21

The human capacities for overcoming prepotent actions and flexibly switching between tasks represent cornerstones of cognitive control. Functional neuroimaging has implicated a diverse set of brain regions contributing to each of these cognitive control processes. However, the extent to which attentional switching and response conflict draw on shared or distinct neural mechanisms remains unclear. The current study examined the neural correlates of response conflict and attentional switching using event-related functional magnetic resonance imaging (fMRI) and a fully randomized 2×2 design. We manipulated an arrow-word version of the Stroop task to measure conflict and switching in the context of a single task decision, in response to a common set of stimuli. Under these common conditions, both behavioral and imaging data showed significant main effects of conflict and switching but no interaction. However, conjunction analyses identified frontal regions involved in both switching and response conflict, including the dorsal anterior cingulate cortex (dACC) and left inferior frontal junction. In addition, connectivity analyses demonstrated task-dependent functional connectivity patterns between dACC and inferior temporal cortex for attentional switching and between dACC and posterior parietal cortex for response conflict. These results suggest that the brain makes use of shared frontal regions, but can dynamically modulate the connectivity patterns of some of those regions, to deal with attentional switching and response conflict. Copyright © 2012 Elsevier B.V. All rights reserved.

Optimal all-optical switching of a microcavity resonance in the telecom range using the electronic Kerr effect.

PubMed

Yüce, Emre; Ctistis, Georgios; Claudon, Julien; Gérard, Jean-Michel; Vos, Willem L

2016-01-11

We have switched GaAs/AlAs and AlGaAs/AlAs planar microcavities that operate in the "Original" (O) telecom band by exploiting the instantaneous electronic Kerr effect. We observe that the resonance frequency reversibly shifts within one picosecond when the nanostructure is pumped with low-energy photons. We investigate experimentally and theoretically the role of several parameters: the material backbone and its electronic bandgap, the quality factor, and the duration of the switch pulse. The magnitude of the frequency shift is reduced when the backbone of the central λ-layer has a greater electronic bandgap compared to the cavity resonance frequency and the frequency of the pump. This observation is caused by the fact that pumping with photon energies near the bandgap resonantly enhances the switched magnitude. We thus find that cavities operating in the telecom O-band are more amenable to ultrafast Kerr switching than those operating at lower frequencies, such as the C-band. Our results indicate that the large bandgap of AlGaAs/AlAs cavity allows to tune both the pump and the probe to the telecom range to perform Kerr switching without detrimental two-photon absorption. We observe that the magnitude of the resonance frequency shift decreases with increasing quality factor of the cavity. Our model shows that the magnitude of the resonance frequency shift depends on the pump pulse duration and is maximized when the duration matches the cavity storage time to within a factor two. In our experiments, we obtain a maximum shift of the cavity resonance relative to the cavity linewidth of 20%. We project that the shift of the cavity resonance can be increased twofold with a pump pulse duration that better matches the cavity storage time. We provide the essential parameter settings for different materials so that the frequency shift of the cavity resonance can be maximized using the electronic Kerr effect.

Switching from reaching to navigation: differential cognitive strategies for spatial memory in children and adults.

PubMed

Belmonti, Vittorio; Cioni, Giovanni; Berthoz, Alain

2015-07-01

Navigational and reaching spaces are known to involve different cognitive strategies and brain networks, whose development in humans is still debated. In fact, high-level spatial processing, including allocentric location encoding, is already available to very young children, but navigational strategies are not mature until late childhood. The Magic Carpet (MC) is a new electronic device translating the traditional Corsi Block-tapping Test (CBT) to navigational space. In this study, the MC and the CBT were used to assess spatial memory for navigation and for reaching, respectively. Our hypothesis was that school-age children would not treat MC stimuli as navigational paths, assimilating them to reaching sequences. Ninety-one healthy children aged 6 to 11 years and 18 adults were enrolled. Overall short-term memory performance (span) on both tests, effects of sequence geometry, and error patterns according to a new classification were studied. Span increased with age on both tests, but relatively more in navigational than in reaching space, particularly in males. Sequence geometry specifically influenced navigation, not reaching. The number of body rotations along the path affected MC performance in children more than in adults, and in women more than in men. Error patterns indicated that navigational sequences were increasingly retained as global paths across development, in contrast to separately stored reaching locations. A sequence of spatial locations can be coded as a navigational path only if a cognitive switch from a reaching mode to a navigation mode occurs. This implies the integration of egocentric and allocentric reference frames, of visual and idiothetic cues, and access to long-term memory. This switch is not yet fulfilled at school age due to immature executive functions. © 2014 John Wiley & Sons Ltd.

Radial microstrip slotline feed network for circular mobile communications array

NASA Technical Reports Server (NTRS)

Simons, Rainee N.; Kelly, Eron S.; Lee, Richard Q.; Taub, Susan R.

1994-01-01

In mobile and satellite communications there is a need for low cost and low profile antennas which have a toroidal pattern. Antennas that have been developed for mobile communications include a L-Band electronically steered stripline phased array, a Ka-Band mechanically steered elliptical reflector antenna and a Ka-Band printed dipole. In addition, a L-Band mechanically steered microstrip array, a L-Band microstrip phased array tracking antenna for mounting on a car roof and an X-Band radial line slotted waveguide antenna have been demonstrated. In the above electronically scanned printed arrays, the individual element radiates normally to the plane of the array and hence require a phase shifter to scan the beam towards the horizon. Scanning in the azimuth is by mechanical or electronic steering. An alternate approach is to mount microstrip patch radiators on the surface of a cone to achieve the required elevation angle. The array then scans in the azimuth by beam switching.

Electronic Switch Arrays for Managing Microbattery Arrays

NASA Technical Reports Server (NTRS)

Mojarradi, Mohammad; Alahmad, Mahmoud; Sukumar, Vinesh; Zghoul, Fadi; Buck, Kevin; Hess, Herbert; Li, Harry; Cox, David

2008-01-01

Integrated circuits have been invented for managing the charging and discharging of such advanced miniature energy-storage devices as planar arrays of microscopic energy-storage elements [typically, microscopic electrochemical cells (microbatteries) or microcapacitors]. The architecture of these circuits enables implementation of the following energy-management options: dynamic configuration of the elements of an array into a series or parallel combination of banks (subarrarys), each array comprising a series of parallel combination of elements; direct addressing of individual banks for charging/or discharging; and, disconnection of defective elements and corresponding reconfiguration of the rest of the array to utilize the remaining functional elements to obtain the desited voltage and current performance. An integrated circuit according to the invention consists partly of a planar array of field-effect transistors that function as switches for routing electric power among the energy-storage elements, the power source, and the load. To connect the energy-storage elements to the power source for charging, a specific subset of switches is closed; to connect the energy-storage elements to the load for discharging, a different specific set of switches is closed. Also included in the integrated circuit is circuitry for monitoring and controlling charging and discharging. The control and monitoring circuitry, the switching transistors, and interconnecting metal lines are laid out on the integrated-circuit chip in a pattern that registers with the array of energy-storage elements. There is a design option to either (1) fabricate the energy-storage elements in the corresponding locations on, and as an integral part of, this integrated circuit; or (2) following a flip-chip approach, fabricate the array of energy-storage elements on a separate integrated-circuit chip and then align and bond the two chips together.

Development of Code-Switching: A Case Study on a Turkish/English/Arabic Multilingual Child

ERIC Educational Resources Information Center

Tunaz, Mehmet

2016-01-01

The purpose of this research was to investigate the early code switching patterns of a simultaneous multilingual subject (Aris) in accordance with Muysken's (2000) code switching typology: insertion and alternation. Firstly, the records of naturalistic spontaneous conversations were obtained from the parents via e-mail, phone calls and…

Stimulation of contacts in ventral but not dorsal subthalamic nucleus normalizes response switching in Parkinson's disease

PubMed Central

Greenhouse, Ian; Gould, Sherrie; Houser, Melissa; Aron, Adam R.

2014-01-01

Switching between responses is a key executive function known to rely on the frontal cortex and the basal ganglia. Here we aimed to establish with greater anatomical specificity whether such switching could be mediated via different possible frontal–basal-ganglia circuits. Accordingly, we stimulated dorsal vs. ventral contacts of electrodes in the subthalamic nucleus (STN) in Parkinson's patients during switching performance, and also studied matched controls. The patients underwent three sessions: once with bilateral dorsal contact stimulation, once with bilateral ventral contact stimulation, and once Off stimulation. Patients Off stimulation showed abnormal patterns of switching, and stimulation of the ventral contacts but not the dorsal contacts normalized the pattern of behavior relative to controls. This provides some of the first evidence in humans that stimulation of dorsal vs. ventral STN DBS contacts has differential effects on executive function. As response switching is an executive function known to rely on prefrontal cortex, these results suggest that ventral contact stimulation affected an executive/associative cortico-basal ganglia circuit. PMID:23562963

Electronic logic to enhance switch reliability in detecting openings and closures of redundant switches

DOEpatents

Cooper, James A.

1986-01-01

A logic circuit is used to enhance redundant switch reliability. Two or more switches are monitored for logical high or low output. The output for the logic circuit produces a redundant and failsafe representation of the switch outputs. When both switch outputs are high, the output is high. Similarly, when both switch outputs are low, the logic circuit's output is low. When the output states of the two switches do not agree, the circuit resolves the conflict by memorizing the last output state which both switches were simultaneously in and produces the logical complement of this output state. Thus, the logic circuit of the present invention allows the redundant switches to be treated as if they were in parallel when the switches are open and as if they were in series when the switches are closed. A failsafe system having maximum reliability is thereby produced.

High power RF coaxial switch

NASA Technical Reports Server (NTRS)

Caro, E. R. (Inventor)

1980-01-01

A coaxial switch capable of operating in a vacuum with high RF power in the 1.2 GHz range without multipactor breakdown, and without relying on pressurization with an inert gas is described. The RF carrying conductors of the switch are surrounded with a high grade solid dielectric, thus eliminating any gaps in which electrons can accelerate.

Direct laser interference patterning of ophthalmic polydimethylsiloxane (PDMS) polymers

NASA Astrophysics Data System (ADS)

Sola, D.; Lavieja, C.; Orera, A.; Clemente, M. J.

2018-07-01

The inscription of diffractive elements in ophthalmic polymers and ocular tissues to induce refractive index changes is of great interest in the fields of Optics and Ophthalmology. In this work fabrication of linear periodic patterns in polydimethylsiloxane (PDMS) intraocular lenses by means of the direct laser interference patterning (DLIP) technique was studied. A Q-Switch Nd:YAG laser coupled to second and third harmonic modules emitting linearly polarized 4 ns pulses at 355 nm with 20 Hz repetition rate was used as the laser source. Laser processing parameters were modified to produce the linear patterns. Processed samples were characterized by means of optical confocal microscopy, Scanning Electron Microscopy SEM, Energy Dispersive X-ray Spectroscopy EDX, Attenuated Total Reflectance-Infrared Spectroscopy ATR-FTIR, and Raman Spectroscopy. Depending on the laser parameters both photo-thermal and photo-chemical damage were observed in the DLIP irradiated areas. Finally, diffractive techniques were used to characterize the diffraction gratings inscribed in the samples resulting in a refractive index change of 1.9 × 10-2 under illumination of a 632.8 nm He-Ne laser.

Automatic switching matrix

DOEpatents

Schlecht, Martin F.; Kassakian, John G.; Caloggero, Anthony J.; Rhodes, Bruce; Otten, David; Rasmussen, Neil

1982-01-01

An automatic switching matrix that includes an apertured matrix board containing a matrix of wires that can be interconnected at each aperture. Each aperture has associated therewith a conductive pin which, when fully inserted into the associated aperture, effects electrical connection between the wires within that particular aperture. Means is provided for automatically inserting the pins in a determined pattern and for removing all the pins to permit other interconnecting patterns.

Power Supply Fault Tolerant Reliability Study

DTIC Science & Technology

1991-04-01

easier to design than for equivalent bipolar transistors. MCDONNELL DOUGLAS ELECTRONICS SYSTEMS COMPANY 9. Base circuitry should be designed to drive...SWITCHING REGULATORS (Ref. 28), SWITCHING AND LINEAR POWER SUPPLY DESIGN (Ref. 25) 6. Sequence the turn-off/turn-on logic in an orderly and controllable ...for equivalent bipolar transistors. MCDONNELL DOUGLAS ELECTRONICS SYSTEMS COMPANY 8. Base circuitry should be designed to drive the transistor into

Assessing the potential of surface-immobilized molecular logic machines for integration with solid state technology.

PubMed

Dunn, Katherine E; Trefzer, Martin A; Johnson, Steven; Tyrrell, Andy M

2016-08-01

Molecular computation with DNA has great potential for low power, highly parallel information processing in a biological or biochemical context. However, significant challenges remain for the field of DNA computation. New technology is needed to allow multiplexed label-free readout and to enable regulation of molecular state without addition of new DNA strands. These capabilities could be provided by hybrid bioelectronic systems in which biomolecular computing is integrated with conventional electronics through immobilization of DNA machines on the surface of electronic circuitry. Here we present a quantitative experimental analysis of a surface-immobilized OR gate made from DNA and driven by strand displacement. The purpose of our work is to examine the performance of a simple representative surface-immobilized DNA logic machine, to provide valuable information for future work on hybrid bioelectronic systems involving DNA devices. We used a quartz crystal microbalance to examine a DNA monolayer containing approximately 5×10(11)gatescm(-2), with an inter-gate separation of approximately 14nm, and we found that the ensemble of gates took approximately 6min to switch. The gates could be switched repeatedly, but the switching efficiency was significantly degraded on the second and subsequent cycles when the binding site for the input was near to the surface. Otherwise, the switching efficiency could be 80% or better, and the power dissipated by the ensemble of gates during switching was approximately 0.1nWcm(-2), which is orders of magnitude less than the power dissipated during switching of an equivalent array of transistors. We propose an architecture for hybrid DNA-electronic systems in which information can be stored and processed, either in series or in parallel, by a combination of molecular machines and conventional electronics. In this architecture, information can flow freely and in both directions between the solution-phase and the underlying electronics via surface-immobilized DNA machines that provide the interface between the molecular and electronic domains. Copyright © 2016 Elsevier Ireland Ltd. All rights reserved.

Advances in integrated photonic circuits for packet-switched interconnection

NASA Astrophysics Data System (ADS)

Williams, Kevin A.; Stabile, Ripalta

2014-03-01

Sustained increases in capacity and connectivity are needed to overcome congestion in a range of broadband communication network nodes. Packet routing and switching in the electronic domain are leading to unsustainable energy- and bandwidth-densities, motivating research into hybrid solutions: optical switching engines are introduced for massive-bandwidth data transport while the electronic domain is clocked at more modest GHz rates to manage routing. Commercially-deployed optical switching engines using MEMS technologies are unwieldy and too slow to reconfigure for future packet-based networking. Optoelectronic packet-compliant switch technologies have been demonstrated as laboratory prototypes, but they have so far mostly used discretely pigtailed components, which are impractical for control plane development and product assembly. Integrated photonics has long held the promise of reduced hardware complexity and may be the critical step towards packet-compliant optical switching engines. Recently a number of laboratories world-wide have prototyped optical switching circuits using monolithic integration technology with up to several hundreds of integrated optical components per chip. Our own work has focused on multi-input to multi-output switching matrices. Recently we have demonstrated 8×8×8λ space and wavelength selective switches using gated cyclic routers and 16×16 broadband switching chips using monolithic multi-stage networks. We now operate these advanced circuits with custom control planes implemented with FPGAs to explore real time packet routing in multi-wavelength, multi-port test-beds. We review our contributions in the context of state of the art photonic integrated circuit technology and packet optical switching hardware demonstrations.

Selectively active markers for solving of the partial occlusion problem in matchmoving and chromakeying workflow

NASA Astrophysics Data System (ADS)

Mazurek, Przemysław

2013-09-01

Matchmoving (Match Moving) is the process used for the estimation of camera movements for further integration of acquired video image with computer graphics. The estimation of movements is possible using pattern recognition, 2D and 3D tracking algorithms. The main problem for the workflow is the partial occlusion of markers by the actor, because manual rotoscoping is necessary for fixing of the chroma-keyed footage. In the paper, the partial occlusion problem is solved using the invented, selectively active electronic markers. The sensor network with multiple infrared links detects occlusion state (no-occlusion, partial, full) and switch LED's based markers.

Direction-division multiplexed holographic free-electron-driven light sources

NASA Astrophysics Data System (ADS)

Clarke, Brendan P.; MacDonald, Kevin F.; Zheludev, Nikolay I.

2018-01-01

We report on a free-electron-driven light source with a controllable direction of emission. The source comprises a microscopic array of plasmonic surface-relief holographic domains, each tailored to direct electron-induced light emission at a selected wavelength into a collimated beam in a prescribed direction. The direction-division multiplexed source is tested by driving it with the 30 kV electron beam of a scanning electron microscope: light emission, at a wavelength of 800 nm in the present case, is switched among different output angles by micron-scale repositioning of the electron injection point among domains. Such sources, with directional switching/tuning possible at picosecond timescales, may be applied to field-emission and surface-conduction electron-emission display technologies, optical multiplexing, and charged-particle-beam position metrology.

Budesonide inhaler device switch patterns in an asthma population in Swedish clinical practice (ASSURE).

PubMed

Ekberg-Jansson, A; Svenningsson, I; Rågdell, P; Stratelis, G; Telg, G; Thuresson, M; Nilsson, F

2015-10-01

Dry powder inhaler (DPI) device switch in asthma treatment could potentially increase with the entrance of new devices. We examined the switch patterns of budesonide (BUD) DPI analogues available in Sweden. This observational real-life study linked primary healthcare medical records data from the Västra Götaland region to national Swedish registries, and included asthma patients (ICD-10-CM J45) prescribed BUD in a multidose DPI. Index date: first dispense of BUD DPI. Switch date: prescription of another BUD DPI device. Study outcomes (switch vs. non-switch) were exacerbations and prescription of short-acting β2 -agonists. Study period was 1 July 2005 to 31 October 2013. Overall, 15,169 asthma patients were on treatment with BUD DPI; 1178 (7.35%) switched to another BUD DPI during the study. Pair-wise 1:1 matching of switchers vs. non-switchers resulted in two groups of 463 patients each (mean age 36 years, 55% female patients). A 25% higher exacerbation rate was seen postswitch (0.40 vs. 0.32; p = 0.047). Switchers were 4.5 year younger and had lower medication possession rate than non-switchers. Switch without primary healthcare visit did not differ between groups regarding consultations and exacerbations (no visit 4.96 and 0.90; visit 4.29 and 0.77, respectively). However, patients without primary healthcare visit at switch had significantly more outpatient hospital visits (2.01 vs. 0.81; p < 0.001). Considering the low switch rate, asthma patients and physicians in Swedish general practice seem reluctant to switch to another BUD DPI device. Switch, especially without primary healthcare visit, was associated with decreased asthma control resulting in higher exacerbation rate and more outpatient hospital visits. © 2015 John Wiley & Sons Ltd.

Experimental investigation on the effect of plasma jet in the triggered discharge process of a gas switch

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

Tie, W., E-mail: twh.110.666@163.com, E-mail: 84470220@qq.com; Xi'an Jiaotong University, Xi'an 710049; Liu, S.

The temporal and spatial evolution of a plasma jet generated by a spark discharge was observed. The electron temperature and density were obtained under different time and gas pressures by optical emission spectroscopy. Moreover, the discharge process of the plasma-jet triggered gas switch was recorded and analyzed at the lowest working coefficient. The results showed that the plasma jet moved forward in a bullet mode, and the advancing velocity increased with the decrease of pressure, and decreased with time growing. At initial time, the maximum velocity of a plasma jet could reach 3.68 × 10{sup 6 }cm/s. The electron temperature decreased from 2.0 eVmore » to 1.3 eV, and the electron density increased from 3.1 × 10{sup 15}/cm{sup 3} to 6.3 × 10{sup 15}/cm{sup 3} at the initial moment as the gas pressure increases from 0.1 MPa to 0.32 MPa. For a two-gap gas switch, the discharge performances were more depended on the second discharge spark gap (gap 2). Because plasma jet promoted the discharge in Gap 2, the gas switch operating in mode II had better triggered discharge characteristics. In the discharge process, the plasma-jet triggering had the effect of non-penetrating inducing, which not only provided initial electrons for reducing statistical lag but also enhanced the local electric field. The discharge was initiated and accelerated from electron avalanche to streamer. Therefore, a fast discharge was occurred in the gas switch.« less

Electronic logic for enhanced switch reliability

DOEpatents

Cooper, J.A.

1984-01-20

A logic circuit is used to enhance redundant switch reliability. Two or more switches are monitored for logical high or low output. The output for the logic circuit produces a redundant and fail-safe representation of the switch outputs. When both switch outputs are high, the output is high. Similarly, when both switch outputs are low, the logic circuit's output is low. When the output states of the two switches do not agree, the circuit resolves the conflict by memorizing the last output state which both switches were simultaneously in and produces the logical complement of this output state. Thus, the logic circuit of the present invention allows the redundant switches to be treated as if they were in parallel when the switches are open and as if they were in series when the switches are closed. A failsafe system having maximum reliability is thereby produced.

Induction of Metamorphosis Causes Differences in Sex-Specific Allocation Patterns in Axolotls (Ambystoma mexicanum) that Have Different Growth Histories.

PubMed

Clarkson, Pamela M; Beachy, Christopher K

2015-12-01

We tested the hypothesis that salamanders growing at different rates would have allocation patterns that differ among male and female metamorphic and larval salamanders. We raised individual axolotls, Ambystoma mexicanum , on four food regimes: constant high growth (throughout the experiment), constant low growth (restricted throughout the experiment), high growth switched to low growth (ad libitum switched after 140 d to restricted), and low growth switched to high growth (restricted switched after 140 d to ad libitum). Because axolotls are obligate paedomorphs, we exposed half of the salamanders to thyroid hormone to induce metamorphosis. We assayed growth and dissected and weighed gonads and fat bodies. Salamanders that were switched from restricted to ad libitum food regime delayed metamorphosis. In all treatment groups, females had larger gonads than males and males had larger fat bodies than females. The association between storage and reproduction differed between larvae and metamorphs and depended on sex.

Stress-induced reversible and irreversible ferroelectric domain switching

NASA Astrophysics Data System (ADS)

Chen, Zibin; Huang, Qianwei; Wang, Feifei; Ringer, Simon P.; Luo, Haosu; Liao, Xiaozhou

2018-04-01

Ferroelectric materials have been extensively explored for applications in electronic devices because of their ferroelectric/ferroelastic domain switching behaviour under electric bias or mechanical stress. Recent findings on applying mechanical loading to manipulate reversible logical signals in non-volatile ferroelectric memory devices make ferroelectric materials more attractive to scientists and engineers. However, the dynamical microscopic structural behaviour of ferroelectric domains under stress is not well understood, which limits the applications of ferroelectric/ferroelastic switching in memory devices. Here, the kinetics of reversible and irreversible ferroelectric domain switching induced by mechanical stress in relaxor-based ferroelectrics was explored. In-situ transmission electron microscopy investigation revealed that 90° ferroelastic and 180° ferroelectric domain switching can be induced by low and high mechanical stresses. The nucleation and growth of nanoscale domains overwhelm the defect-induced pinning effect on the stable micro-domain walls. This study provides deep insights for exploring the mechanical kinetics for ferroelectric/ferroelastic domains and a clear pathway to overcome the domain pinning effect of defects in ferroelectrics.

Tunable dielectric response, resistive switching, and unconventional transport in SrTiO3

NASA Astrophysics Data System (ADS)

Mikheev, Evgeny

The first section of this thesis discusses integration of SR TiO3 grown by molecular beam epitaxy (MBE) in vertical device structures. One target application is as a tunable dielectric. Parallel plate capacitors based on epitaxial Pt(001) bottom electrodes and (Ba,Sr)TiO 3 dielectric layers grown by MBE are demonstrated. Optimization of structural quality of the vertical stack is shown to produce very low dielectric loss combined with very high tunability of the dielectric constant by DC bias. This results in considerable improvement of common figures of merit for varactor performance in comparison to previous reports. Another target application for transition metals oxides is in resistive switching memories, which are based on the hysteretic current-voltage response observed in many oxide-based Schottky junctions and capacitors. A study on the role of metal/oxide interface quality is presented. In particular, the use of epitaxial Pt(001) as Schottky contacts to Nb:SRTiO 3 is shown to suppress resistive switching hysteresis by eliminating unintentional contributions to interface capacitance. Such uncontrolled factors are discussed as a probable root cause for poor reproducibility in resistive switching memories, currently a ubiquitous challenge in the field. Potential routes towards stabilizing reproducible switching through intentional control of defect densities in high-quality structures are discussed, including a proof of concept demonstration using Schottky junctions incorporating intentionally non-stoichiometric SRTiO3 interlayers grown by MBE. The second section of this thesis is concerned with unconventional electronic transport in SRTiO3. A systematic description of scattering mechanisms will be presented for three related material systems: uniformly-doped SRTiO3, two-dimensional electron liquids (2DEL) at SRTiO3/RTiO 3 interfaces (R = Gd, Sm) and confined 2DELs in RTiO3/SRTiO3/ RTiO3 quantum wells. In particular, the prevalence of a well-defined T2 scattering rate in doped SRTiO3 will be discussed as being incompatible with its traditional assignment as electron-electron scattering in a Fermi liquid. In the case of ultrathin SRTiO3 quantum wells bound by RTiO3, evidence will be presented for the existence of a quantum critical point. This refers to a quantum phase transition at zero temperature towards an ordered phase in SRTiO 3. This transition is driven by increasing confinement of the 2DEL, with a critical point located at the 5 SrO layer thickness of SRTiO 3. It is manifested in anomalous temperature exponents of the power law resistivity. Additionally, a well-defined trend for the separation of the Hall and longitudinal scattering rates will be presented, analogously to a similar effect observed in the normal state of high-Tc superconductors. In particular, a unique pattern of residual scattering separation was documented, consistent with a quantum critical correction to the Hall lifetime that is divergent at the quantum critical point.

High power ferrite microwave switch

NASA Technical Reports Server (NTRS)

Bardash, I.; Roschak, N. K.

1975-01-01

A high power ferrite microwave switch was developed along with associated electronic driver circuits for operation in a spaceborne high power microwave transmitter in geostationary orbit. Three units were built and tested in a space environment to demonstrate conformance to the required performance characteristics. Each unit consisted of an input magic-tee hybrid, two non-reciprocal latching ferrite phase shifters, an out short-slot 3 db quadrature coupler, a dual driver electronic circuit, and input logic interface circuitry. The basic mode of operation of the high power ferrite microwave switch is identical to that of a four-port, differential phase shift, switchable circulator. By appropriately designing the phase shifters and electronic driver circuits to operate in the flux-transfer magnetization mode, power and temperature insensitive operation was achieved. A list of the realized characteristics of the developed units is given.

Nonlinear space charge dynamics in mixed ionic-electronic conductors: Resistive switching and ferroelectric-like hysteresis of electromechanical response

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

Morozovska, Anna N.; Morozovsky, Nicholas V.; Eliseev, Eugene A.

We performed self-consistent modelling of nonlinear electrotransport and electromechanical response of thin films of mixed ionic-electronic conductors (MIEC) allowing for steric effects of mobile charged defects (ions, protons, or vacancies), electron degeneration, and Vegard stresses. We establish correlations between the features of the nonlinear space-charge dynamics, current-voltage, and bending-voltage curves for different types of the film electrodes. A pronounced ferroelectric-like hysteresis of the bending-voltage loops and current maxima on the double hysteresis current-voltage loops appear for the electron-transport electrodes. The double hysteresis loop with pronounced humps indicates a memristor-type resistive switching. The switching occurs due to the strong nonlinear couplingmore » between the electronic and ionic subsystems. A sharp meta-stable maximum of the electron density appears near one open electrode and moves to another one during the periodic change of applied voltage. Our results can explain the nonlinear nature and correlation of electrical and mechanical memory effects in thin MIEC films. The analytical expression proving that the electrically induced bending of MIEC films can be detected by interferometric methods is derived.« less

Patterns of Contraceptive Adoption, Continuation, and Switching after Delivery among Malawian Women.

PubMed

Kopp, Dawn M; Rosenberg, Nora E; Stuart, Gretchen S; Miller, William C; Hosseinipour, Mina C; Bonongwe, Phylos; Mwale, Mwawi; Tang, Jennifer H

2017-01-01

Women who report use of postpartum family planning may not continue their initial method or use it consistently. Understanding the patterns of method uptake, discontinuation, and switching among women after delivery is important to promote uptake and continuation of effective methods of contraception. This is a secondary analysis of 634 Malawian women enrolled into a prospective cohort study after delivery. They completed baseline surveys upon enrollment and follow-up telephone surveys 3, 6, and 12 months post-delivery. Women were included in this analysis if they had completed at least the 3- and 6-month post-delivery surveys. Descriptive statistics were used to assess contraceptive method mix and patterns of switching, whereas Pearson's χ2 tests were used for bivariable analyses to compare characteristics of women who continued and discontinued their initial post-delivery contraceptive method. Among the 479 women included in this analysis, the use of abstinence/traditional methods decreased and the use of long-acting and permanent methods (LAPM) increased over time. Almost half (47%) discontinued the contraceptive method reported at 3-months post-delivery; women using injectables or LAPM at 3-months post-delivery were significantly more likely to continue their method than those using non-modern methods (p<0.001). Of the 216 women who switched methods, 82% switched to a more or equally effective method. The change in contraceptive method mix and high rate of contraceptive switching in the first 12 months postpartum highlights a need to assist women in accessing effective contraceptives soon after delivery.

A reversible single-molecule switch based on activated antiaromaticity

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

Yin, Xiaodong; Zang, Yaping; Zhu, Liangliang

Single-molecule electronic devices provide researchers with an unprecedented ability to relate novel physical phenomena to molecular chemical structures. Typically, conjugated aromatic molecular backbones are relied upon to create electronic devices, where the aromaticity of the building blocks is used to enhance conductivity. We capitalize on the classical physical organic chemistry concept of Hückel antiaromaticity by demonstrating a single-molecule switch that exhibits low conductance in the neutral state and, upon electrochemical oxidation, reversibly switches to an antiaromatic high-conducting structure. We form single-molecule devices using the scanning tunneling microscope–based break-junction technique and observe an on/off ratio of ~70 for a thiophenylidene derivativemore » that switches to an antiaromatic state with 6-4-6-p electrons. Through supporting nuclear magnetic resonance measurements, we show that the doubly oxidized core has antiaromatic character and we use density functional theory calculations to rationalize the origin of the high-conductance state for the oxidized single-molecule junction. Together, our work demonstrates how the concept of antiaromaticity can be exploited to create single-molecule devices that are highly conducting.« less

A reversible single-molecule switch based on activated antiaromaticity

DOE PAGES

Yin, Xiaodong; Zang, Yaping; Zhu, Liangliang; ...

2017-10-27

Single-molecule electronic devices provide researchers with an unprecedented ability to relate novel physical phenomena to molecular chemical structures. Typically, conjugated aromatic molecular backbones are relied upon to create electronic devices, where the aromaticity of the building blocks is used to enhance conductivity. We capitalize on the classical physical organic chemistry concept of Hückel antiaromaticity by demonstrating a single-molecule switch that exhibits low conductance in the neutral state and, upon electrochemical oxidation, reversibly switches to an antiaromatic high-conducting structure. We form single-molecule devices using the scanning tunneling microscope–based break-junction technique and observe an on/off ratio of ~70 for a thiophenylidene derivativemore » that switches to an antiaromatic state with 6-4-6-p electrons. Through supporting nuclear magnetic resonance measurements, we show that the doubly oxidized core has antiaromatic character and we use density functional theory calculations to rationalize the origin of the high-conductance state for the oxidized single-molecule junction. Together, our work demonstrates how the concept of antiaromaticity can be exploited to create single-molecule devices that are highly conducting.« less

New scheme for image edge detection using the switching mechanism of nonlinear optical material

NASA Astrophysics Data System (ADS)

Pahari, Nirmalya; Mukhopadhyay, Sourangshu

2006-03-01

The limitations of electronics in conducting parallel arithmetic, algebraic, and logic processing are well known. Very high-speed (terahertz) performance cannot be expected in conventional electronic mechanisms. To achieve such performance we can introduce optics instead of electronics for information processing, computing, and data handling. Nonlinear optical material (NOM) is a successful candidate in this regard to play a major role in the domain of optically controlled switching systems. The character of some NOMs is such as to reflect the probe beam in the presence of two read beams (or pump beams) exciting the material from opposite directions, using the principle of four-wave mixing. In image processing, edge extraction from an image is an important and essential task. Several optical methods of digital image processing are used for properly evaluating the image edges. We propose here a new method of image edge detection, extraction, and enhancement by use of AND-based switching operations with NOM. In this process we have used the optically inverted image of a supplied image. This can be obtained by the EXOR switching operation of the NOM.

The effect of doping Sb on the electronic structure and the device characteristics of Ovonic Threshold Switches based on Ge-Se.

PubMed

Shin, Sang-Yeol; Choi, J M; Seo, Juhee; Ahn, Hyung-Woo; Choi, Yong Gyu; Cheong, Byung-ki; Lee, Suyoun

2014-11-18

The Ovonic Threshold Switch (OTS) based on an amorphous chalcogenide material has attracted much interest as a promising candidate for a high-performance thin-film switching device enabling 3D-stacking of memory devices. In this work, we studied on the electronic structure of amorphous Sb-doped Ge(0.6)Se(0.4) (in atomic mole fraction) film and its characteristics as to OTS devices. From the optical absorption spectroscopy measurement, the band gap (Eg) was found to decrease with increasing Sb content. In addition, as Sb content increased, the activation energy (Ea) for electrical conduction was found to decrease down to about one third of Eg from a half. As to the device characteristics, we found that the threshold switching voltage (Vth) drastically decreased with the Sb content. These results, being accountable in terms of the changes in the bonding configuration of constituent atoms as well as in the electronic structure such as the energy gap and trap states, advance an effective method of compositional adjustment to modulate Vth of an OTS device for various applications.

Photochromic molecules as building blocks for molecular electronics.

PubMed

Peter, Belser

2010-01-01

Energy and electron transfer processes can be easily induced by a photonic excitation of a donor metal complex ([Ru(bpy)3]2), which is connected via a wire-type molecular fragment to an acceptor metal complex ([Os(bpy)3]2+). The rate constant for the transfer process can be determined by emission measurements of the two connected metal complexes. The system can be modified by incorporation of a switching unit or an interrupter into the wire, influencing the transfer process. Such a molecular device corresponds to an interrupter, mimic the same function applied in molecular electronics. We have used organic switches, which show photochromic properties. By irradiation with light of different wavelengths, the switch changes its functionality by a photochemical reaction from an OFF- to an ON-state and vice versa. The ON- respectively OFF-state is manifested by a color change but also in different conductivity properties for energy and electron transfer processes. Therefore, the mentioned molecular device can work as a simple interrupter, controlling the rate of the transfer processes.

Direct Observation of Conducting Filaments in Tungsten Oxide Based Transparent Resistive Switching Memory.

PubMed

Qian, Kai; Cai, Guofa; Nguyen, Viet Cuong; Chen, Tupei; Lee, Pooi See

2016-10-05

Transparent nonvolatile memory has great potential in integrated transparent electronics. Here, we present highly transparent resistive switching memory using stoichiometric WO 3 film produced by cathodic electrodeposition with indium tin oxide electrodes. The memory device demonstrates good optical transmittance, excellent operative uniformity, low operating voltages (+0.25 V/-0.42 V), and long retention time (>10 4 s). Conductive atomic force microscopy, ex situ transmission electron microscopy, and X-ray photoelectron spectroscopy experiments directly confirm that the resistive switching effects occur due to the electric field-induced formation and annihilation of the tungsten-rich conductive channel between two electrodes. Information on the physical and chemical nature of conductive filaments offers insightful design strategies for resistive switching memories with excellent performances. Moreover, we demonstrate the promising applicability of the cathodic electrodeposition method for future resistive memory devices.

Extreme nonlinear terahertz electro-optics in diamond for ultrafast pulse switching

NASA Astrophysics Data System (ADS)

Shalaby, Mostafa; Vicario, Carlo; Hauri, Christoph P.

2017-03-01

Polarization switching of picosecond laser pulses is a fundamental concept in signal processing [C. Chen and G. Liu, Annu. Rev. Mater. Sci. 16, 203 (1986); V. R. Almeida et al., Nature 431, 1081 (2004); and A. A. P. Pohl et al., Photonics Sens. 3, 1 (2013)]. Conventional switching devices rely on the electro-optical Pockels effect and work at radio frequencies. The ensuing gating time of several nanoseconds is a bottleneck for faster switches which is set by the performance of state-of-the-art high-voltage electronics. Here we show that by substituting the electric field of several kV/cm provided by modern electronics by the MV/cm field of a single-cycle THz laser pulse, the electro-optical gating process can be driven orders of magnitude faster, at THz frequencies. In this context, we introduce diamond as an exceptional electro-optical material and demonstrate a pulse gating time as fast as 100 fs using sub-cycle THz-induced Kerr nonlinearity. We show that THz-induced switching in the insulator diamond is fully governed by the THz pulse shape. The presented THz-based electro-optical approach overcomes the bandwidth and switching speed limits of conventional MHz/GHz electronics and establishes the ultrafast electro-optical gating technology for the first time in the THz frequency range. We finally show that the presented THz polarization gating technique is applicable for advanced beam diagnostics. As a first example, we demonstrate tomographic reconstruction of a THz pulse in three dimensions.

Should We Still Be Talking about Leaving? A Comparative Examination of Social Inequality in Undergraduate Patterns of Switching Majors. WCER Working Paper No. 2014-5

ERIC Educational Resources Information Center

Ferrare, Joseph J.; Lee, You-Geon

2014-01-01

Despite extensive efforts to increase the number of undergraduates majoring and persisting in science, math, engineering, and technology (STEM) fields, there is surprisingly little understanding of recent patterns of switching from these majors to those in other fields of study. In addition, little is known about whether the racial, class, and…

SOX1 links the function of neural patterning and Notch signalling in the ventral spinal cord during the neuron-glial fate switch

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

Genethliou, Nicholas; Panayiotou, Elena; Department of Biological Sciences, University of Cyprus, P.O. Box 20537, 1678 Nicosia

2009-12-25

During neural development the transition from neurogenesis to gliogenesis, known as the neuron-glial ({Nu}/G) fate switch, requires the coordinated function of patterning factors, pro-glial factors and Notch signalling. How this process is coordinated in the embryonic spinal cord is poorly understood. Here, we demonstrate that during the N/G fate switch in the ventral spinal cord (vSC) SOX1 links the function of neural patterning and Notch signalling. We show that, SOX1 expression in the vSC is regulated by PAX6, NKX2.2 and Notch signalling in a domain-specific manner. We further show that SOX1 regulates the expression of Hes1 and that loss ofmore » Sox1 leads to enhanced production of oligodendrocyte precursors from the pMN. Finally, we show that Notch signalling functions upstream of SOX1 during this fate switch and is independently required for the acquisition of the glial fate perse by regulating Nuclear Factor I A expression in a PAX6/SOX1/HES1/HES5-independent manner. These data integrate functional roles of neural patterning factors, Notch signalling and SOX1 during gliogenesis.« less

Prevalence and patterns of antidepressant switching amongst primary care patients in the UK.

PubMed

Mars, Becky; Heron, Jon; Gunnell, David; Martin, Richard M; Thomas, Kyla H; Kessler, David

2017-05-01

Non-response to antidepressant treatment is a substantial problem in primary care, and many patients with depression require additional second-line treatments. This study aimed to examine the prevalence and patterns of antidepressant switching in the UK, and identify associated demographic and clinical factors. Cohort analysis of antidepressant prescribing data from the Clinical Practice Research Datalink, a large, anonymised UK primary care database. The sample included 262,844 patients who initiated antidepressant therapy between 1 January 2005 and 31 June 2011. 9.3% of patients switched to a different antidepressant product, with most switches (60%) occurring within 8 weeks of the index date. The proportion switching was similar for selective serotonin reuptake inhibitors (SSRIs), tricyclic antidepressants and other antidepressants (9.3%, 9.8% and 9.2%, respectively). Most switches were to an SSRI (64.5%), and this was the preferred option regardless of initial antidepressant class. Factors predictive of switching included male gender, age, and history of self-harm and psychiatric illness. Over one in every 11 patients who initiates antidepressant therapy will switch medication, suggesting that initial antidepressant treatment has been unsatisfactory. Evidence to guide choice of second-line treatment for individual patients is currently limited. Additional research comparing different pharmacological and psychological second-line treatment strategies is required in order to inform guidelines and improve patient outcomes.

Neural correlates of task switching in paternal 15q11-q13 deletion Prader-Willi syndrome.

PubMed

Woodcock, Kate A; Humphreys, Glyn W; Oliver, Chris; Hansen, Peter C

2010-12-02

We report a first study of brain activity linked to task switching in individuals with Prader-Willi syndrome (PWS). PWS individuals show a specific cognitive deficit in task switching which may be associated with the display of temper outbursts and repetitive questioning. The performance of participants with PWS and typically developing controls was matched in a cued task switching procedure, and brain activity was contrasted on switching and non-switching blocks using fMRI. Individuals with PWS did not show the typical frontal-parietal pattern of neural activity associated with switching blocks, with significantly reduced activation in regions of the posterior parietal and ventromedial prefrontal cortices. We suggest that this is linked to a difficulty in PWS in setting appropriate attentional weights to enable task-set reconfiguration. In addition to this, PWS individuals did not show the typical pattern of deactivation, with significantly less deactivation in an anterior region of the ventromedial prefrontal cortex. One plausible explanation for this is that individuals with PWS show dysfunction within the default mode network, which has been linked to attentional control. The data point to functional changes in the neural circuitry supporting task switching in PWS even when behavioural performance is matched to controls and thus highlight neural mechanisms that may be involved in a specific pathway between genes, cognition and behaviour. Copyright © 2010 Elsevier B.V. All rights reserved.

Tests of a low-pressure switch protected by a saturating inductor

NASA Astrophysics Data System (ADS)

Lauer, E. J.; Birx, D. L.

1981-10-01

A triggered low-pressure switch was tested switching a charged capacitor across a damping resistor simulating a transformer. A series saturating inductor protected the switch from electron beam anode damage. The capacitor was 15 micro F and charge voltages up to 50 kV were used. The time to current maximum was 5 to 8 micro S. The current terminated at about 50 micro S and voltage could be reapplied at about 100 micro S.

Evaluation of the optical switching characteristics of erbium-doped fibres for the development of a fibre Bragg grating sensor interrogator

NASA Astrophysics Data System (ADS)

Rigas, Evangelos; Correia, R.; Stathopoulos, N. A.; Savaidis, S. P.; James, S. W.; Bhattacharyya, D.; Kirby, P. B.; Tatam, R. P.

2014-05-01

A polling topology that employs optical switching based on the properties of erbium-doped fibres (EDFs) is used to interrogate an array of FBGs. The properties of the EDF are investigated in its pumped and un-pumped states and the EDFs' switching properties are evaluated by comparing them with a high performance electronically controlled MEM optical switch. Potential advantages of the proposed technique are discussed.

Facilitation of Ferroelectric Switching via Mechanical Manipulation of Hierarchical Nanoscale Domain Structures.

PubMed

Chen, Zibin; Hong, Liang; Wang, Feifei; Ringer, Simon P; Chen, Long-Qing; Luo, Haosu; Liao, Xiaozhou

2017-01-06

Heterogeneous ferroelastic transition that produces hierarchical 90° tetragonal nanodomains via mechanical loading and its effect on facilitating ferroelectric domain switching in relaxor-based ferroelectrics were explored. Combining in situ electron microscopy characterization and phase-field modeling, we reveal the nature of the transition process and discover that the transition lowers by 40% the electrical loading threshold needed for ferroelectric domain switching. Our results advance the fundamental understanding of ferroelectric domain switching behavior.

Inverse Proportional Relationship Between Switching-Time Length and Fractal-Like Structure for Continuous Tracking Movement

NASA Astrophysics Data System (ADS)

Hirakawa, Takehito; Suzuki, Hiroo; Gohara, Kazutoshi; Yamamoto, Yuji

We investigate the relationship between the switching-time length T and the fractal-like feature that characterizes the behavior of dissipative dynamical systems excited by external temporal inputs for tracking movement. Seven healthy right-handed male participants were asked to continuously track light-emitting diodes that were located on the right and left sides in front of them. These movements were performed under two conditions: when the same input pattern was repeated (the periodic-input condition) and when two different input patterns were switched stochastically (the switching-input condition). The repeated time lengths of input patterns during these conditions were 2.00, 1.00, 0.75, 0.50, 0.35, and 0.25s. The movements of a lever held between a participant’s thumb and index finger were measured by a motion-capture system and were analyzed with respect to position and velocity. The condition in which the same input was repeated revealed that two different stable trajectories existed in a cylindrical state space, while the condition in which the inputs were switched induced transitions between these two trajectories. These two different trajectories were considered as excited attractors. The transitions between the two excited attractors produced eight trajectories; they were then characterized by a fractal-like feature as a third-order sequence effect. Moreover, correlation dimensions, which are typically used to evaluate fractal-like features, calculated from the set on the Poincaré section increased as the switching-time length T decreased. These results suggest that an inverse proportional relationship exists between the switching-time length T and the fractal-like feature of human movement.

Blocking-state influence on shot noise and conductance in quantum dots

NASA Astrophysics Data System (ADS)

Harabula, M.-C.; Ranjan, V.; Haller, R.; Fülöp, G.; Schönenberger, C.

2018-03-01

Quantum dots (QDs) investigated through electron transport measurements often exhibit varying, state-dependent tunnel couplings to the leads. Under specific conditions, weakly coupled states can result in a strong suppression of the electrical current, and they are correspondingly called blocking states. Using the combination of conductance and shot noise measurements, we investigate blocking states in carbon nanotube (CNT) QDs. We report negative differential conductance and super-Poissonian noise. The enhanced noise is the signature of electron bunching, which originates from random switches between the strongly and weakly conducting states of the QD. Negative differential conductance appears here when the blocking state is an excited state. In this case, at the threshold voltage where the blocking state becomes populated, the current is reduced. Using a master equation approach, we provide numerical simulations reproducing both the conductance and the shot noise pattern observed in our measurements.

Real world treatment patterns in chronic myeloid leukemia patients newly initiated on tyrosine kinase inhibitors in an U.S. integrated healthcare system.

PubMed

Rashid, Nazia; Koh, Han A; Lin, Kathy J; Stwalley, Brian; Felber, Eugene

2018-06-01

Purpose To evaluate treatment patterns in patients diagnosed with incident chronic myelogenous leukemia (CML) newly initiating therapy with imatinib, dasatinib, or nilotinib. Patients were followed to determine switching and discontinuation rates. Factors associated with switching or discontinuation from index TKI therapy, reasons for discontinuation based on electronic chart notes, and frequency of laboratory monitoring were assessed during the follow-up period. Methods A retrospective cohort study was conducted in chronic myelogenous leukemia patients aged ≥ 18 years who were identified from the Kaiser Permanente Southern California (KPSC) Cancer Registry database during the study time period of 1 January 2007 to 12 December 2013. The index date was defined as the date of the first TKI prescription (imatinib, dasatinib, or nilotinib) identified during the study time period with no prior history of TKI use within 12 months. Patients had to have continuous membership with drug benefit eligibility and no prior history of stem cell transplant (SCT) or other cancers during the 12 months prior to the index date. Baseline characteristics were identified during 12 months prior to the index date and outcomes were identified during the follow-up period after the index date. All patients were followed from index TKI therapy until end of study time period (12 December 2014), death, stem cell transplant, or disenrollment from the health plan unless one of the following occurred first: a patient switched their index therapy, or a patient discontinued their index therapy. Forward stepwise selection multivariable logistic regression models were used to evaluate factors associated with patients who continued therapy compared to those who switched or discontinued therapy with the index TKI. Chart notes were reviewed 30 days prior and 30 days post index TKI discontinuation to evaluate reasons for discontinuation. Molecular and cytogenetic testing frequency was also assessed during the follow-up period among the different patient groups. Results Two hundred sixteen patients were identified with incident chronic myelogenous leukemia and use of TKI therapy: 189 (87.5%) received imatinib, 19 (8.8%) received dasatinib, and 8 (3.7%) received nilotinib. The mean age on index date was 53 years and 63% were male; 103 patients (48%) continued on their index therapy, while 62 patients (28%) switched, and 51 patients (24%) discontinued.

Dynamic Trial-by-Trial Recoding of Task-Set Representations in the Frontoparietal Cortex Mediates Behavioral Flexibility

PubMed Central

Qiao, Lei; Zhang, Lijie

2017-01-01

Cognitive flexibility forms the core of the extraordinary ability of humans to adapt, but the precise neural mechanisms underlying our ability to nimbly shift between task sets remain poorly understood. Recent functional magnetic resonance imaging (fMRI) studies employing multivoxel pattern analysis (MVPA) have shown that a currently relevant task set can be decoded from activity patterns in the frontoparietal cortex, but whether these regions support the dynamic transformation of task sets from trial to trial is not clear. Here, we combined a cued task-switching protocol with human (both sexes) fMRI, and harnessed representational similarity analysis (RSA) to facilitate a novel assessment of trial-by-trial changes in neural task-set representations. We first used MVPA to define task-sensitive frontoparietal and visual regions and found that neural task-set representations on switch trials are less stably encoded than on repeat trials. We then exploited RSA to show that the neural representational pattern dissimilarity across consecutive trials is greater for switch trials than for repeat trials, and that the degree of this pattern dissimilarity predicts behavior. Moreover, the overall neural pattern of representational dissimilarities followed from the assumption that repeating sets, compared with switching sets, results in stronger neural task representations. Finally, when moving from cue to target phase within a trial, pattern dissimilarities tracked the transformation from previous-trial task representations to the currently relevant set. These results provide neural evidence for the longstanding assumptions of an effortful task-set reconfiguration process hampered by task-set inertia, and they demonstrate that frontoparietal and stimulus processing regions support “dynamic adaptive coding,” flexibly representing changing task sets in a trial-by-trial fashion. SIGNIFICANCE STATEMENT Humans can fluently switch between different tasks, reflecting an ability to dynamically configure “task sets,” rule representations that link stimuli to appropriate responses. Recent studies show that neural signals in frontal and parietal brain regions can tell us which of two tasks a person is currently performing. However, it is not known whether these regions are also involved in dynamically reconfiguring task-set representations when switching between tasks. Here we measured human brain activity during task switching and tracked the similarity of neural task-set representations from trial to trial. We show that frontal and parietal brain regions flexibly recode changing task sets in a trial-by-trial fashion, and that task-set similarity over consecutive trials predicts behavior. PMID:28972126

Molecular switches and motors on surfaces.

PubMed

Pathem, Bala Krishna; Claridge, Shelley A; Zheng, Yue Bing; Weiss, Paul S

2013-01-01

Molecular switches and motors respond structurally, electronically, optically, and/or mechanically to external stimuli, testing and potentially enabling extreme miniaturization of optoelectronic devices, nanoelectromechanical systems, and medical devices. The assembly of motors and switches on surfaces makes it possible both to measure the properties of individual molecules as they relate to their environment and to couple function between assembled molecules. In this review, we discuss recent progress in assembling molecular switches and motors on surfaces, measuring static and dynamic structures, understanding switching mechanisms, and constructing functional molecular materials and devices. As demonstrative examples, we choose a representative molecule from three commonly studied classes including molecular switches, photochromic molecules, and mechanically interlocked molecules. We conclude by offering perspectives on the future of molecular switches and motors on surfaces.

Design Method of Digital Optimal Control Scheme and Multiple Paralleled Bridge Type Current Amplifier for Generating Gradient Magnetic Fields in MRI Systems

NASA Astrophysics Data System (ADS)

Watanabe, Shuji; Takano, Hiroshi; Fukuda, Hiroya; Hiraki, Eiji; Nakaoka, Mutsuo

This paper deals with a digital control scheme of multiple paralleled high frequency switching current amplifier with four-quadrant chopper for generating gradient magnetic fields in MRI (Magnetic Resonance Imaging) systems. In order to track high precise current pattern in Gradient Coils (GC), the proposal current amplifier cancels the switching current ripples in GC with each other and designed optimum switching gate pulse patterns without influences of the large filter current ripple amplitude. The optimal control implementation and the linear control theory in GC current amplifiers have affinity to each other with excellent characteristics. The digital control system can be realized easily through the digital control implementation, DSPs or microprocessors. Multiple-parallel operational microprocessors realize two or higher paralleled GC current pattern tracking amplifier with optimal control design and excellent results are given for improving the image quality of MRI systems.

Specifying and calibrating instrumentations for wideband electronic power measurements. [in switching circuits

NASA Technical Reports Server (NTRS)

Lesco, D. J.; Weikle, D. H.

1980-01-01

The wideband electric power measurement related topics of electronic wattmeter calibration and specification are discussed. Tested calibration techniques are described in detail. Analytical methods used to determine the bandwidth requirements of instrumentation for switching circuit waveforms are presented and illustrated with examples from electric vehicle type applications. Analog multiplier wattmeters, digital wattmeters and calculating digital oscilloscopes are compared. The instrumentation characteristics which are critical to accurate wideband power measurement are described.

Laser based analysis using a passively Q-switched laser employing analysis electronics and a means for detecting atomic optical emission of the laser media

DOEpatents

Woodruff, Steven D.; Mcintyre, Dustin L.

2016-03-29

A device for Laser based Analysis using a Passively Q-Switched Laser comprising an optical pumping source optically connected to a laser media. The laser media and a Q-switch are positioned between and optically connected to a high reflectivity mirror (HR) and an output coupler (OC) along an optical axis. The output coupler (OC) is optically connected to the output lens along the optical axis. A means for detecting atomic optical emission comprises a filter and a light detector. The optical filter is optically connected to the laser media and the optical detector. A control system is connected to the optical detector and the analysis electronics. The analysis electronics are optically connected to the output lens. The detection of the large scale laser output production triggers the control system to initiate the precise timing and data collection from the detector and analysis.

Lightning protection of full authority digital electronic systems

NASA Astrophysics Data System (ADS)

Crofts, David

1991-08-01

Modern electronic systems are vulnerable to transient and they now provide safety critical functions such as full authority digital electronic control (FADEC) units for fly by wire aircraft. Of the traditional suppression technologies available diodes have gained the wider acceptance, however, they lack the current handling capacity to meet existing threat levels. The development of high speed fold back devices where, at a specified voltage, the off state resistance switches to a very low on state one has provided the equivalent to a semiconductor spark gap. The size of the technology enables it to be integrated into connectors of interconnection cables. To illustrate the performance the technology was developed to meet the Lightning Protection requirements for FADEC units within aeroengines. Work was also carried out to study switching behavior with the waveform 5, the 500 us, 10 kA pulse applied to cable assemblies. This test enabled all the switches in a connector to be fired simultaneously.

Lightning protection of full authority digital electronic systems

NASA Technical Reports Server (NTRS)

Crofts, David

1991-01-01

Modern electronic systems are vulnerable to transient and they now provide safety critical functions such as full authority digital electronic control (FADEC) units for fly by wire aircraft. Of the traditional suppression technologies available diodes have gained the wider acceptance, however, they lack the current handling capacity to meet existing threat levels. The development of high speed fold back devices where, at a specified voltage, the off state resistance switches to a very low on state one has provided the equivalent to a semiconductor spark gap. The size of the technology enables it to be integrated into connectors of interconnection cables. To illustrate the performance the technology was developed to meet the Lightning Protection requirements for FADEC units within aeroengines. Work was also carried out to study switching behavior with the waveform 5, the 500 us, 10 kA pulse applied to cable assemblies. This test enabled all the switches in a connector to be fired simultaneously.

Negative differential resistance and switch behavior of T-BxNy (x, y = 5, 6, 11) molecular junctions

NASA Astrophysics Data System (ADS)

Wang, Shi-Liang; Yang, Chuan-Lu; Wang, Mei-Shan; Ma, Xiao-Guang; Xin, Jian-Guo

2017-05-01

The electronic transport properties of T-BxNy (x, y = 5, 6, 11) molecular junction are investigated based on first-principle density functional theory and non-equilibrium Green's function method. Strong negative differential resistance (NDR) behavior is observed for T-B5N6 molecule under negative and positive bias voltages, with an obvious switch effect for T-B6N5. However, only small NDR is shown for the complex of the two molecules. The projected device density of states, the spatial distribution of molecular orbitals, and the effect of transmission spectra under various bias voltages on the electronic transport properties are analyzed. The obvious effect of bias voltage on the changes in the electronic distribution of frontier molecular orbitals is responsible for the NDR or switch behavior. Therefore, different functional molecular devices can be obtained with different structures of T-BxNy.

A Passively Q-Switched, CW-Pumped Fe:ZnSe Laser

DTIC Science & Technology

2014-03-01

passively Q-switched microchip lasers using semiconductor saturable absorbers,” J. Opt. Soc. Amer. B, Opt. Phys., vol. 16, no. 3, pp. 376–388, Mar. 1999...204 IEEE JOURNAL OF QUANTUM ELECTRONICS, VOL. 50, NO. 3, MARCH 2014 A Passively Q-Switched, CW-Pumped Fe:ZnSe Laser Jonathan W. Evans, Patrick A...Berry, and Kenneth L. Schepler Abstract— We report the demonstration of high-average-power passively Q-switched laser oscillation from Fe2+ ions in zinc

Restrike Particle Beam Experiments on a Dense Plasma Focus. Opening Switch Research on a Dense Plasma Focus.

DTIC Science & Technology

1985-06-01

Research on this grant has focused on plasma focus experiments in the areas of particle beam generation and as a potential repetitive opening switch...as were scaling laws for the increase of electron energy and current with input energy. The potential of the plasma focus as an opening switch was...delay line technique. The observed frequencies were most consistent with the lower hybrid frequency. Keywords include: Dense Plasma Focus , Particle Beam Generation, Opening Switch, Load Experiments, Pulsed Power.

Molecular engineering and measurements to test hypothesized mechanisms in single molecule conductance switching.

PubMed

Moore, Amanda M; Dameron, Arrelaine A; Mantooth, Brent A; Smith, Rachel K; Fuchs, Daniel J; Ciszek, Jacob W; Maya, Francisco; Yao, Yuxing; Tour, James M; Weiss, Paul S

2006-02-15

Six customized phenylene-ethynylene-based oligomers have been studied for their electronic properties using scanning tunneling microscopy to test hypothesized mechanisms of stochastic conductance switching. Previously suggested mechanisms include functional group reduction, functional group rotation, backbone ring rotation, neighboring molecule interactions, bond fluctuations, and hybridization changes. Here, we test these hypotheses experimentally by varying the molecular designs of the switches; the ability of the molecules to switch via each hypothetical mechanism is selectively engineered into or out of each molecule. We conclude that hybridization changes at the molecule-surface interface are responsible for the switching we observe.

Note: Cryogenic heat switch with stepper motor actuator

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

Melcher, B. S., E-mail: bsmelche@syr.edu; Timbie, P. T., E-mail: pttimbie@wisc.edu

2015-12-15

A mechanical cryogenic heat switch has been developed using a commercially available stepper motor and control electronics. The motor requires 4 leads, each carrying a maximum, pulsed current of 0.5 A. With slight modifications of the stepper motor, the switch functions reliably in vacuum at temperatures between 300 K and 4 K. The switch generates a clamping force of 262 N at room temperature. At 4 K it achieves an “on state” thermal conductance of 5.04 mW/K and no conductance in the “off state.” The switch is optimized for cycling an adiabatic demagnetization refrigerator.

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

Jacobina, C.B.; Silva, E.R.C. da; Lima, A.M.N.

This paper investigates the PWM operation of a four switch three phase inverter (FSTPI), in the case of digital implementation. Different switching sequence strategies for vector control are described and a digital scalar method is also presented. The influence of different switching patterns on the output voltage symmetry, current waveform and switching frequency are examined. The results obtained by employing the vector and scalar strategies are compared and a relationship between them is established. This comparison is based on analytical study and is corroborated either by the computer simulations and by the experimental results. The vector approach makes ease themore » understanding and analysis of the FSTPI, as well the choice of a PWM pattern. However, similar results may be obtained through the scalar approach, which has a simpler implementation. The experimental results of the use of the FSTPI and digital PWM to control an induction motor are presented.« less

Abnormal bipolar resistive switching behavior in a Pt/GaO{sub 1.3}/Pt structure

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

Guo, D. Y.; Wu, Z. P.; Zhang, L. J.

2015-07-20

A stable and repeatable abnormal bipolar resistive switching behavior was observed in a Pt/GaO{sub 1.3}/Pt sandwich structure without an electroforming process. The low resistance state (LRS) and the high resistance state (HRS) of the device can be distinguished clearly and be switched reversibly under a train of the voltage pulses. The LRS exhibits a conduction of electron tunneling, while the HRS shows a conduction of Schottky-type. The observed phenomena are considered to be related to the migration of oxygen vacancies which changes the space charge region width of the metal/semiconductor interface and results in a different electron transport mechanism.

A Magnetoresistive Heat Switch for the Continuous ADR

NASA Technical Reports Server (NTRS)

Canavan, E. R.; Dipirro, M. J.; Jackson, M.; Panek, J.; Shirron, P. J.; Tuttle, J. G.; Krebs, C. (Technical Monitor)

2001-01-01

In compensated elemental metals at low temperature, a several Tesla field can suppress electronic heat conduction so thoroughly that heat is effectively carried by phonons alone. In approximately one mm diameter single crystal samples with impurity concentrations low enough that electron conduction is limited by surface scattering, the ratio of zerofield to high-field thermal conductivity can exceed ten thousand. We have used this phenomenon to build a compact, solid-state heat switch with no moving parts and no enclosed fluids. The time scale for switching states is limited by time scale for charging the magnet that supplies the controlling field. Our design and fabrication techniques overcome the difficulties associated with manufacturing and assembling parts from single crystal tungsten. A clear disadvantage of the magnetoresistive switch is the mass and complexity of the magnet system for the controlling field. We have discovered a technique of minimizing this mass and complexity, applicable to the continuous adiabatic demagnetization refrigerator.

Lidar Electro-Optic Beam Switch with a Liquid Crystal Variable Retarder

NASA Technical Reports Server (NTRS)

Baer, James

2012-01-01

A document discusses a liquid crystal variable retarder, an electro-optic element that changes the polarization of an optical beam in response to a low-voltage electronic signal. This device can be fabricated so that the element creates, among other states, a half-wave of retardance that can be reduced to a very small retardance. When aligned to a polarized source, this can act to rotate the polarization by 90 in one state, but generate no rotation in the other state. If the beam is then incident on a polarization beam splitter, it will efficiently switch from one path to the other when the voltage is applied. The laser beam switching system has no moving parts, improving reliability over mechanical switching. It is low cost, tolerant of high laser power density, and needs only simple drive electronics, minimizing the required system resources.

Laser activated diffuse discharge switch

DOEpatents

Christophorou, Loucas G.; Hunter, Scott R.

1988-01-01

The invention is a gas mixture for a diffuse discharge switch which is capable of changing from a conducting state to an insulating state in the presence of electrons upon the introduction of laser light. The mixture is composed of a buffer gas such as nitrogen or argon and an electron attaching gas such as C.sub.6 H.sub.5 SH, C.sub.6 H.sub.5 SCH.sub.3, CH.sub.3 CHO and CF.sub.3 CHO wherein the electron attachment is brought on by indirect excitation of molecules to long-lived states by exposure to laser light.

Electron tunnelling through single azurin molecules can be on/off switched by voltage pulses

NASA Astrophysics Data System (ADS)

Baldacchini, Chiara; Kumar, Vivek; Bizzarri, Anna Rita; Cannistraro, Salvatore

2015-05-01

Redox metalloproteins are emerging as promising candidates for future bio-optoelectronic and nano-biomemory devices, and the control of their electron transfer properties through external signals is still a crucial task. Here, we show that a reversible on/off switching of the electron current tunnelling through a single protein can be achieved in azurin protein molecules adsorbed on gold surfaces, by applying appropriate voltage pulses through a scanning tunnelling microscope tip. The observed changes in the hybrid system tunnelling properties are discussed in terms of long-sustained charging of the protein milieu.

Is there a general task switching ability?

PubMed

Yehene, Einat; Meiran, Nachshon

2007-11-01

Participants were tested on two analogous task switching paradigms involving Shape/Size tasks and Vertical/Horizontal tasks, respectively, and three measures of psychometric intelligence, tapping fluid, crystallized and perceptual speed abilities. The paradigms produced similar patterns of group mean reaction times (RTs) and the vast majority of the participants showed switching cost (switch RT minus repeat RT), mixing cost (repeat RT minus single-task RT) and congruency effects. The shared intra-individual variance across paradigms and with psychometric intelligence served as criteria for general ability. Structural equations modeling indicated that switching cost with ample preparation ("residual cost") and mixing cost met these criteria. However, switching cost with little preparation and congruency effects were predominantly paradigm specific.

Changing patterns of tumor necrosis factor inhibitor use in 9074 patients with rheumatoid arthritis.

PubMed

Yazici, Yusuf; Krasnokutsky, Svetlana; Barnes, Jaime P; Hines, Patricia L; Wang, Jason; Rosenblatt, Lisa

2009-05-01

Patients with rheumatoid arthritis (RA) commonly switch between tumor necrosis factor (TNF) inhibitors after failing to control disease activity. Much of the clinical data that support switching to a second TNF agent when one agent fails to work has come from small, short-term studies. We utilized a US insurance claims database to determine patterns of use such as dose escalation, time to discontinuation, and switching between TNF inhibitors in patients with RA. A retrospective analysis was performed using an insurance claims database in the US from 2000 to 2005. TNF inhibitor use, time to switch, dose escalation, and continuation times were analyzed in patients with RA. Nine thousand seventy-four patients with RA started TNF inhibitors during the period 2000 to 2005. Etanercept was the most commonly used TNF inhibitor; infliximab had the highest duration of continuation, about 50% at 2 years. In addition, infliximab showed higher rates of dose escalation compared to etanercept and adalimumab. For all TNF inhibitors, time to switching decreased from 2000 to 2005. TNF inhibitor use patterns changed from 2000 to 2005, with more frequent changes among the different TNF inhibitors and a shorter duration of treatment before the change. Only about 50% of TNF inhibitors are still continued at 2 years, reflecting the difference between randomized clinical trials and real-world experience.

Patterns of patterns of synchronization: Noise induced attractor switching in rings of coupled nonlinear oscillators

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

Emenheiser, Jeffrey; Department of Physics, University of California, Davis, California 95616; Chapman, Airlie

Following the long-lived qualitative-dynamics tradition of explaining behavior in complex systems via the architecture of their attractors and basins, we investigate the patterns of switching between distinct trajectories in a network of synchronized oscillators. Our system, consisting of nonlinear amplitude-phase oscillators arranged in a ring topology with reactive nearest-neighbor coupling, is simple and connects directly to experimental realizations. We seek to understand how the multiple stable synchronized states connect to each other in state space by applying Gaussian white noise to each of the oscillators' phases. To do this, we first analytically identify a set of locally stable limit cyclesmore » at any given coupling strength. For each of these attracting states, we analyze the effect of weak noise via the covariance matrix of deviations around those attractors. We then explore the noise-induced attractor switching behavior via numerical investigations. For a ring of three oscillators, we find that an attractor-switching event is always accompanied by the crossing of two adjacent oscillators' phases. For larger numbers of oscillators, we find that the distribution of times required to stochastically leave a given state falls off exponentially, and we build an attractor switching network out of the destination states as a coarse-grained description of the high-dimensional attractor-basin architecture.« less

A solid-state dielectric elastomer switch for soft logic

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

Chau, Nixon; Slipher, Geoffrey A., E-mail: geoffrey.a.slipher.civ@mail.mil; Mrozek, Randy A.

In this paper, we describe a stretchable solid-state electronic switching material that operates at high voltage potentials, as well as a switch material benchmarking technique that utilizes a modular dielectric elastomer (artificial muscle) ring oscillator. The solid-state switching material was integrated into our oscillator, which self-started after 16 s and performed 5 oscillations at a frequency of 1.05 Hz with 3.25 kV DC input. Our materials-by-design approach for the nickel filled polydimethylsiloxane based switch has resulted in significant improvements over previous carbon grease-based switches in four key areas, namely, sharpness of switching behavior upon applied stretch, magnitude of electrical resistance change, ease ofmore » manufacture, and production rate. Switch lifetime was demonstrated to be in the range of tens to hundreds of cycles with the current process. An interesting and potentially useful strain-based switching hysteresis behavior is also presented.« less

A single-stage optical load-balanced switch for data centers.

PubMed

Huang, Qirui; Yeo, Yong-Kee; Zhou, Luying

2012-10-22

Load balancing is an attractive technique to achieve maximum throughput and optimal resource utilization in large-scale switching systems. However current electronic load-balanced switches suffer from severe problems in implementation cost, power consumption and scaling. To overcome these problems, in this paper we propose a single-stage optical load-balanced switch architecture based on an arrayed waveguide grating router (AWGR) in conjunction with fast tunable lasers. By reuse of the fast tunable lasers, the switch achieves both functions of load balancing and switching through the AWGR. With this architecture, proof-of-concept experiments have been conducted to investigate the feasibility of the optical load-balanced switch and to examine its physical performance. Compared to three-stage load-balanced switches, the reported switch needs only half of optical devices such as tunable lasers and AWGRs, which can provide a cost-effective solution for future data centers.

Patterns of Contraceptive Adoption, Continuation, and Switching after Delivery among Malawian Women

PubMed Central

Rosenberg, Nora E.; Stuart, Gretchen S.; Miller, William C.; Hosseinipour, Mina C.; Bonongwe, Phylos; Mwale, Mwawi; Tang, Jennifer H.

2017-01-01

Women who report use of postpartum family planning may not continue their initial method or use it consistently. Understanding the patterns of method uptake, discontinuation, and switching among women after delivery is important to promote uptake and continuation of effective methods of contraception. This is a secondary analysis of 634 Malawian women enrolled into a prospective cohort study after delivery. They completed baseline surveys upon enrollment and follow-up telephone surveys 3, 6, and 12 months post-delivery. Women were included in this analysis if they had completed at least the 3- and 6-month post-delivery surveys. Descriptive statistics were used to assess contraceptive method mix and patterns of switching, whereas Pearson’s χ2 tests were used for bivariable analyses to compare characteristics of women who continued and discontinued their initial post-delivery contraceptive method. Among the 479 women included in this analysis, the use of abstinence/traditional methods decreased and the use of long-acting and permanent methods (LAPM) increased over time. Almost half (47%) discontinued the contraceptive method reported at 3-months post-delivery; women using injectables or LAPM at 3-months post-delivery were significantly more likely to continue their method than those using non-modern methods (p<0.001). Of the 216 women who switched methods, 82% switched to a more or equally effective method. The change in contraceptive method mix and high rate of contraceptive switching in the first 12 months postpartum highlights a need to assist women in accessing effective contraceptives soon after delivery. PMID:28107404

Reversible solvatomagnetic switching in a single-ion magnet from an entatic state† †Electronic supplementary information (ESI) available: Preparation methods and physical characterization data. Crystallographic refinement and computational details. Additional figures (Fig. S1–S12) and tables (Tables S1–S5). CCDC 952077 and 938463. For ESI and crystallographic data in CIF or other electronic format see DOI: 10.1039/c6sc05188j Click here for additional data file. Click here for additional data file.

PubMed Central

Vallejo, J.; Viciano-Chumillas, M.; Castro, I.; Amorós, P.; Déniz, M.; Ruiz-Pérez, C.; Yuste-Vivas, C.; Krzystek, J.; Julve, M.; Lloret, F.

2017-01-01

A vast impact on molecular nanoscience can be achieved using simple transition metal complexes as dynamic chemical systems to perform specific and selective tasks under the control of an external stimulus that switches “ON” and “OFF” their electronic properties. While the interest in single-ion magnets (SIMs) lies in their potential applications in information storage and quantum computing, the switching of their slow magnetic relaxation associated with host–guest processes is insufficiently explored. Herein, we report a unique example of a mononuclear cobalt(ii) complex in which geometrical constraints are the cause of easy and reversible water coordination and its release. As a result, a reversible and selective colour and SIM behaviour switch occurs between a “slow-relaxing” deep red anhydrous material (compound 1) and its “fast-relaxing” orange hydrated form (compound 2). The combination of this optical and magnetic switching in this new class of vapochromic and thermochromic SIMs offers fascinating possibilities for designing multifunctional molecular materials. PMID:28580105

3-DIMENSIONAL Optoelectronic

NASA Astrophysics Data System (ADS)

Krishnamoorthy, Ashok Venketaraman

This thesis covers the design, analysis, optimization, and implementation of optoelectronic (N,M,F) networks. (N,M,F) networks are generic space-division networks that are well suited to implementation using optoelectronic integrated circuits and free-space optical interconnects. An (N,M,F) networks consists of N input channels each having a fanout F_{rm o}, M output channels each having a fanin F_{rm i}, and Log_{rm K}(N/F) stages of K x K switches. The functionality of the fanout, switching, and fanin stages depends on the specific application. Three applications of optoelectronic (N,M,F) networks are considered. The first is an optoelectronic (N,1,1) content -addressable memory system that achieves associative recall on two-dimensional images retrieved from a parallel-access optical memory. The design and simulation of the associative memory are discussed, and an experimental emulation of a prototype system using images from a parallel-readout optical disk is presented. The system design provides superior performance to existing electronic content-addressable memory chips in terms of capacity and search rate, and uses readily available optical disk and VLSI technologies. Next, a scalable optoelectronic (N,M,F) neural network that uses free-space holographic optical interconnects is presented. The neural architecture minimizes the number of optical transmitters needed, and provides accurate electronic fanin with low signal skew, and dendritic-type fan-in processing capability in a compact layout. Optimal data-encoding methods and circuit techniques are discussed. The implementation of an prototype optoelectronic neural system, and its application to a simple recognition task is demonstrated. Finally, the design, analysis, and optimization of a (N,N,F) self-routing, packet-switched multistage interconnection network is described. The network is suitable for parallel computing and broadband switching applications. The tradeoff between optical and electronic interconnects is examined quantitatively by varying the electronic switch size K. The performance of the (N,N,F) network versus the fanning parameter F, is also analyzed. It is shown that the optoelectronic (N,N,F) networks provide a range of performance-cost alternatives, and offer superior performance-per-cost to fully electronic switching networks and to previous networks designs.

A Lossless Network for Data Acquisition

NASA Astrophysics Data System (ADS)

Jereczek, Grzegorz; Lehmann Miotto, Giovanna; Malone, David; Walukiewicz, Miroslaw

2017-06-01

The bursty many-to-one communication pattern, typical for data acquisition systems, is particularly demanding for commodity TCP/IP and Ethernet technologies. We expand the study of lossless switching in software running on commercial off-the-shelf servers, using the ATLAS experiment as a case study. In this paper, we extend the popular software switch, Open vSwitch, with a dedicated, throughput-oriented buffering mechanism for data acquisition. We compare the performance under heavy congestion on typical Ethernet switches to a commodity server acting as a switch. Our results indicate that software switches with large buffers perform significantly better. Next, we evaluate the scalability of the system when building a larger topology of interconnected software switches, exploiting the integration with software-defined networking technologies. We build an IP-only leaf-spine network consisting of eight software switches running on distinct physical servers as a demonstrator.

A non-volatile organic electrochemical device as a low-voltage artificial synapse for neuromorphic computing

DOE PAGES

van de Burgt, Yoeri; Lubberman, Ewout; Fuller, Elliot J.; ...

2017-02-20

The brain is capable of massively parallel information processing while consuming only ~1- 100 fJ per synaptic event. Inspired by the efficiency of the brain, CMOS-based neural architectures and memristors are being developed for pattern recognition and machine learning. However, the volatility, design complexity and high supply voltages for CMOS architectures, and the stochastic and energy-costly switching of memristors complicate the path to achieve the interconnectivity, information density, and energy efficiency of the brain using either approach. Here we describe an electrochemical neuromorphic organic device (ENODe) operating with a fundamentally different mechanism from existing memristors. ENODe switches at low energymore » (<10 pJ for 10 3 μm 2 devices) and voltage, displays >500 distinct, non-volatile conductance states within a ~1 V range, and achieves high classification accuracy when implemented in neural network simulations. Plastic ENODEs are also fabricated on flexible substrates enabling the integration of neuromorphic functionality in stretchable electronic systems. Mechanical flexibility makes ENODes compatible with 3D architectures, opening a path towards extreme interconnectivity comparable to the human brain.« less

A non-volatile organic electrochemical device as a low-voltage artificial synapse for neuromorphic computing

NASA Astrophysics Data System (ADS)

van de Burgt, Yoeri; Lubberman, Ewout; Fuller, Elliot J.; Keene, Scott T.; Faria, Grégorio C.; Agarwal, Sapan; Marinella, Matthew J.; Alec Talin, A.; Salleo, Alberto

2017-04-01

The brain is capable of massively parallel information processing while consuming only ~1-100 fJ per synaptic event. Inspired by the efficiency of the brain, CMOS-based neural architectures and memristors are being developed for pattern recognition and machine learning. However, the volatility, design complexity and high supply voltages for CMOS architectures, and the stochastic and energy-costly switching of memristors complicate the path to achieve the interconnectivity, information density, and energy efficiency of the brain using either approach. Here we describe an electrochemical neuromorphic organic device (ENODe) operating with a fundamentally different mechanism from existing memristors. ENODe switches at low voltage and energy (<10 pJ for 103 μm2 devices), displays >500 distinct, non-volatile conductance states within a ~1 V range, and achieves high classification accuracy when implemented in neural network simulations. Plastic ENODes are also fabricated on flexible substrates enabling the integration of neuromorphic functionality in stretchable electronic systems. Mechanical flexibility makes ENODes compatible with three-dimensional architectures, opening a path towards extreme interconnectivity comparable to the human brain.

A non-volatile organic electrochemical device as a low-voltage artificial synapse for neuromorphic computing.

PubMed

van de Burgt, Yoeri; Lubberman, Ewout; Fuller, Elliot J; Keene, Scott T; Faria, Grégorio C; Agarwal, Sapan; Marinella, Matthew J; Alec Talin, A; Salleo, Alberto

2017-04-01

The brain is capable of massively parallel information processing while consuming only ∼1-100 fJ per synaptic event. Inspired by the efficiency of the brain, CMOS-based neural architectures and memristors are being developed for pattern recognition and machine learning. However, the volatility, design complexity and high supply voltages for CMOS architectures, and the stochastic and energy-costly switching of memristors complicate the path to achieve the interconnectivity, information density, and energy efficiency of the brain using either approach. Here we describe an electrochemical neuromorphic organic device (ENODe) operating with a fundamentally different mechanism from existing memristors. ENODe switches at low voltage and energy (<10 pJ for 10 3  μm 2 devices), displays >500 distinct, non-volatile conductance states within a ∼1 V range, and achieves high classification accuracy when implemented in neural network simulations. Plastic ENODes are also fabricated on flexible substrates enabling the integration of neuromorphic functionality in stretchable electronic systems. Mechanical flexibility makes ENODes compatible with three-dimensional architectures, opening a path towards extreme interconnectivity comparable to the human brain.

Asynchronous transfer mode distribution network by use of an optoelectronic VLSI switching chip.

PubMed

Lentine, A L; Reiley, D J; Novotny, R A; Morrison, R L; Sasian, J M; Beckman, M G; Buchholz, D B; Hinterlong, S J; Cloonan, T J; Richards, G W; McCormick, F B

1997-03-10

We describe a new optoelectronic switching system demonstration that implements part of the distribution fabric for a large asynchronous transfer mode (ATM) switch. The system uses a single optoelectronic VLSI modulator-based switching chip with more than 4000 optical input-outputs. The optical system images the input fibers from a two-dimensional fiber bundle onto this chip. A new optomechanical design allows the system to be mounted in a standard electronic equipment frame. A large section of the switch was operated as a 208-Mbits/s time-multiplexed space switch, which can serve as part of an ATM switch by use of an appropriate out-of-band controller. A larger section with 896 input light beams and 256 output beams was operated at 160 Mbits/s as a slowly reconfigurable space switch.

New Modulation Method and Control Strategies for Power Electronics Inverters

NASA Astrophysics Data System (ADS)

Aleenejad, Mohsen

The DC to AC power Converters (so-called Inverters) are widely used in industrial applications. The MLIs are becoming increasingly popular in industrial apparatus aimed at medium to high power conversion applications. In comparison to the conventional inverters, they feature superior characteristics such as lower total harmonic distortion (THD), higher efficiency, and lower switching voltage stress. Nevertheless, the superior characteristics come at the price of a more complex topology with an increased number of power electronic switches. The increased number of power electronics switches results in more complicated control strategies for the inverter. Moreover, as the number of power electronic switches increases, the chances of fault occurrence of the switches increases, and thus the inverter's reliability decreases. Due to the extreme monetary ramifications of the interruption of operation in commercial and industrial applications, high reliability for power inverters utilized in these sectors is critical. As a result, developing simple control strategies for normal and fault-tolerant operation of MLIs has always been an interesting topic for researchers in related areas. The purpose of this dissertation is to develop new control and fault-tolerant strategies for the multilevel power inverter. For the normal operation of the inverter, a new high switching frequency technique is developed. The proposed method extends the utilization of the dc link voltage while minimizing the dv/dt of the switches. In the event of a fault, the line voltages of the faulty inverters are unbalanced and cannot be applied to the 3-phase loads. For the faulty condition of the inverter, three novel fault-tolerant techniques are developed. The proposed fault-tolerant strategies generate balanced line voltages without bypassing any healthy and operative inverter element, makes better use of the inverter capacity and generates higher output voltage. These strategies exploit the advantages of the Selective Harmonic Elimination (SHE) and Space Vector Modulation (SVM) methods in conjunction with a slightly modified Fundamental Phase Shift Compensation (FPSC) technique to generate balanced voltages and manipulate voltage harmonics at the same time. The proposed strategies are applicable to several classes of MLIs with three or more voltage levels.

Switch-Independent Task Representations in Frontal and Parietal Cortex.

PubMed

Loose, Lasse S; Wisniewski, David; Rusconi, Marco; Goschke, Thomas; Haynes, John-Dylan

2017-08-16

Alternating between two tasks is effortful and impairs performance. Previous fMRI studies have found increased activity in frontoparietal cortex when task switching is required. One possibility is that the additional control demands for switch trials are met by strengthening task representations in the human brain. Alternatively, on switch trials, the residual representation of the previous task might impede the buildup of a neural task representation. This would predict weaker task representations on switch trials, thus also explaining the performance costs. To test this, male and female participants were cued to perform one of two similar tasks, with the task being repeated or switched between successive trials. Multivoxel pattern analysis was used to test which regions encode the tasks and whether this encoding differs between switch and repeat trials. As expected, we found information about task representations in frontal and parietal cortex, but there was no difference in the decoding accuracy of task-related information between switch and repeat trials. Using cross-classification, we found that the frontoparietal cortex encodes tasks using a generalizable spatial pattern in switch and repeat trials. Therefore, task representations in frontal and parietal cortex are largely switch independent. We found no evidence that neural information about task representations in these regions can explain behavioral costs usually associated with task switching. SIGNIFICANCE STATEMENT Alternating between two tasks is effortful and slows down performance. One possible explanation is that the representations in the human brain need time to build up and are thus weaker on switch trials, explaining performance costs. Alternatively, task representations might even be enhanced to overcome the previous task. Here, we used a combination of fMRI and a brain classifier to test whether the additional control demands under switching conditions lead to an increased or decreased strength of task representations in frontoparietal brain regions. We found that task representations are not modulated significantly by switching processes and generalize across switching conditions. Therefore, task representations in the human brain cannot account for the performance costs associated with alternating between tasks. Copyright © 2017 the authors 0270-6474/17/378033-10$15.00/0.

Media multitasking behavior: concurrent television and computer usage.

PubMed

Brasel, S Adam; Gips, James

2011-09-01

Changes in the media landscape have made simultaneous usage of the computer and television increasingly commonplace, but little research has explored how individuals navigate this media multitasking environment. Prior work suggests that self-insight may be limited in media consumption and multitasking environments, reinforcing a rising need for direct observational research. A laboratory experiment recorded both younger and older individuals as they used a computer and television concurrently, multitasking across television and Internet content. Results show that individuals are attending primarily to the computer during media multitasking. Although gazes last longer on the computer when compared to the television, the overall distribution of gazes is strongly skewed toward very short gazes only a few seconds in duration. People switched between media at an extreme rate, averaging more than 4 switches per min and 120 switches over the 27.5-minute study exposure. Participants had little insight into their switching activity and recalled their switching behavior at an average of only 12 percent of their actual switching rate revealed in the objective data. Younger individuals switched more often than older individuals, but other individual differences such as stated multitasking preference and polychronicity had little effect on switching patterns or gaze duration. This overall pattern of results highlights the importance of exploring new media environments, such as the current drive toward media multitasking, and reinforces that self-monitoring, post hoc surveying, and lay theory may offer only limited insight into how individuals interact with media.

Media Multitasking Behavior: Concurrent Television and Computer Usage

PubMed Central

Gips, James

2011-01-01

Abstract Changes in the media landscape have made simultaneous usage of the computer and television increasingly commonplace, but little research has explored how individuals navigate this media multitasking environment. Prior work suggests that self-insight may be limited in media consumption and multitasking environments, reinforcing a rising need for direct observational research. A laboratory experiment recorded both younger and older individuals as they used a computer and television concurrently, multitasking across television and Internet content. Results show that individuals are attending primarily to the computer during media multitasking. Although gazes last longer on the computer when compared to the television, the overall distribution of gazes is strongly skewed toward very short gazes only a few seconds in duration. People switched between media at an extreme rate, averaging more than 4 switches per min and 120 switches over the 27.5-minute study exposure. Participants had little insight into their switching activity and recalled their switching behavior at an average of only 12 percent of their actual switching rate revealed in the objective data. Younger individuals switched more often than older individuals, but other individual differences such as stated multitasking preference and polychronicity had little effect on switching patterns or gaze duration. This overall pattern of results highlights the importance of exploring new media environments, such as the current drive toward media multitasking, and reinforces that self-monitoring, post hoc surveying, and lay theory may offer only limited insight into how individuals interact with media. PMID:21381969

Finite element based contact analysis of radio frequency MEMs switch membrane surfaces

NASA Astrophysics Data System (ADS)

Liu, Jin-Ya; Chalivendra, Vijaya; Huang, Wenzhen

2017-10-01

Finite element simulations were performed to determine the contact behavior of radio frequency (RF) micro-electro-mechanical (MEM) switch contact surfaces under monotonic and cyclic loading conditions. Atomic force microscopy (AFM) was used to capture the topography of RF-MEM switch membranes and later they were analyzed for multi-scale regular as well as fractal structures. Frictionless, non-adhesive contact 3D finite element analysis was carried out at different length scales to investigate the contact behavior of the regular-fractal surface using an elasto-plastic material model. Dominant micro-scale regular patterns were found to significantly change the contact behavior. Contact areas mainly cluster around the regular pattern. The contribution from the fractal structure is not significant. Under cyclic loading conditions, plastic deformation in the 1st loading/unloading cycle smooth the surface. The subsequent repetitive loading/unloading cycles undergo elastic contact without changing the morphology of the contacting surfaces. The work is expected to shed light on the quality of the switch surface contact as well as the optimum design of RF MEM switch surfaces.

Physics Notes.

ERIC Educational Resources Information Center

School Science Review, 1983

1983-01-01

Presented are physics experiments, laboratory procedures, demonstrations, and classroom materials/activities. Experiments include: speed of sound in carbon dioxide; inverse square law; superluminal velocities; and others. Equipment includes: current switch; electronic switch; and pinhole camera. Discussion of mechanics of walking is also included.…

Design and Operation of a Two-Color Interferometer to Measure Plasma and Neutral Gas Densities in a Laser-Triggered Spark Gap Switch

NASA Astrophysics Data System (ADS)

Camacho, J. F.; Ruden, E. L.; Domonkos, M. T.; Schmitt-Sody, A.; Lucero, A.

2014-10-01

A Mach-Zehnder imaging interferometer, operating with 1064-nm and 532-nm wavelength beams from a short-pulse laser and a frequency-doubled branch, respectively, has been designed and built to simultaneously measure plasma free electron and neutral gas densities profiles within a laser-triggered spark gap switch with a 5-mm gap. The switch will be triggered by focusing a separate 532-nm or 1064-nm laser pulse along the gap's axis to trigger low-jitter breakdown. Illuminating the gap transverse to this axis, the diagnostic will generate interferograms for each wavelength, which will then be numerically converted to phase-shift maps. These will be used to calculate independent line-integrated free electron and neutral density profiles by exploiting their different frequency dispersion curves. The density profiles themselves, then, will be calculated by Abel inversion. Details of the interferometer's design will be presented along with density data obtained using a variety of fill gasses at various pressures. Other switch parameters will be varied as well in order to characterize more fully the performance of the switch.

Analytically derived switching functions for exact H2+ eigenstates

NASA Astrophysics Data System (ADS)

Thorson, W. R.; Kimura, M.; Choi, J. H.; Knudson, S. K.

1981-10-01

Electron translation factors (ETF's) appropriate for slow atomic collisions may be constructed using switching functions. In this paper we derive a set of switching functions for the H2+ system by an analytical "two-center decomposition" of the exact molecular eigenstates. These switching functions are closely approximated by the simple form f=bη, where η is the "angle variable" of prolate spheroidal coordinates. For given united atom angular momentum quantum numbers (l,m), the characteristic parameter blm depends only on the quantity c2=-ɛR22, where ɛ is the electronic binding energy and R the internuclear distance in a.u. The resulting parameters are in excellent agreement with those found in our earlier work by a heuristic "optimization" scheme based on a study of coupling matrix-element behavior for a number of H2+ states. An approximate extension to asymmetric cases (HeH2+) has also been made. Nonadiabatic couplings based on these switching functions have been used in recent close-coupling calculations for H+-H(1s) collisions and He2+-H(1s) collisions at energies 1.0-20 keV.

Real-world health outcomes in adults with moderate-to-severe psoriasis in the United States: a population study using electronic health records to examine patient-perceived treatment effectiveness, medication use, and healthcare resource utilization.

PubMed

Armstrong, April W; Foster, Shonda A; Comer, Brian S; Lin, Chen-Yen; Malatestinic, William; Burge, Russel; Goldblum, Orin

2018-06-28

Little is known regarding real-world health outcomes data among US psoriasis patients, but electronic health records (EHR) that collect structured data at point-of-care may provide opportunities to investigate real-world health outcomes among psoriasis patients. Our objective was to investigate patient-perceived treatment effectiveness, patterns of medication use (duration, switching, and/or discontinuation), healthcare resource utilization, and medication costs using real-world data from psoriasis patients. Data for adults (≥18-years) with a dermatology provider-given diagnosis of psoriasis from 9/2014-9/2015 were obtained from dermatology practices using a widely used US dermatology-specific EHR containing over 500,000 psoriasis patients. Disease severity was captured by static physician's global assessment and body surface area. Patient-perceived treatment effectiveness was assessed by a pre-defined question. Treatment switching and duration were documented. Reasons for discontinuations were assessed using pre-defined selections. Healthcare resource utilization was defined by visit frequency and complexity. From 82,621 patients with psoriasis during the study period, patient-perceived treatment effectiveness was investigated in 2200 patients. The proportion of patients reporting "strongly agree" when asked if their treatment was effective was highest for biologics (73%) and those reporting treatment adherence (55%). In 16,000 patients who received oral systemics and 21,087 patients who received biologics, median treatment duration was longer for those who received biologics (160 vs. 113 days, respectively). Treatment switching was less frequent among patients on systemic monotherapies compared to those on combination therapies. The most common reason for discontinuing biologics was loss of efficacy; the most common reason for discontinuing orals was side effects. In 28,754 patients, higher disease severity was associated with increased healthcare resource utilization (increased visit frequency and complexity). When compared between treatment groups (n = 10,454), healthcare resource utilization was highest for phototherapy. Annual medication costs were higher for biologics ($21,977) than oral systemics ($3413). Real-world research using a widely implemented dermatology EHR provided valuable insights on patient perceived treatment effectiveness, patterns of medication usage, healthcare resource utilization, and medication costs for psoriasis patients in the US. This study and others utilizing EHRs for real-world research may assist clinical and payer decisions regarding the management of psoriasis.

An Electron-Beam Controlled Semiconductor Switch

DTIC Science & Technology

1989-11-01

of the Seventeenth Power Modulator Symposium, Seattle, WA, pp. 214-218. 1986. 21. Bovino , L., ’ioumans,R., Weiner, H., Burke, T . , "Optica lly... Bovino , R. Youmans, M. Weiner, and T. Burke, ’ ’Optically Co ntrolled Semiconducto r Switch for ~lulti-~legawatt Rep-Rated Pulse r s ," Conf. Record...p. 615. (II 1 W. N. Carr, IEEE Trans. Electron Devices, vol. ED-12, p. 531 , 1965. (121 T. Burke, M. Weiner. L. Bovino , and R. Youmans, in Proc

Introduction of Electronic Pressure Scanning at the Royal Aerospace Establishment

DTIC Science & Technology

1991-09-01

electronic pressure scanning system could offer an acciracy the same as or better than that of the mechanical pressure switch system it would replace and...described it as comparable with the kind of problem encountered with pressures in a rotating pressure switch system and suggested two ways around the...sufficient to reduce the system random noise to less than the systematic errors for data from the surface of a pressure plotted model A mechanical pressure

The effect of doping Sb on the electronic structure and the device characteristics of Ovonic Threshold Switches based on Ge-Se

PubMed Central

Shin, Sang-Yeol; Choi, J. M.; Seo, Juhee; Ahn, Hyung-Woo; Choi, Yong Gyu; Cheong, Byung-ki; Lee, Suyoun

2014-01-01

The Ovonic Threshold Switch (OTS) based on an amorphous chalcogenide material has attracted much interest as a promising candidate for a high-performance thin-film switching device enabling 3D-stacking of memory devices. In this work, we studied on the electronic structure of amorphous Sb-doped Ge0.6Se0.4 (in atomic mole fraction) film and its characteristics as to OTS devices. From the optical absorption spectroscopy measurement, the band gap (Eg) was found to decrease with increasing Sb content. In addition, as Sb content increased, the activation energy (Ea) for electrical conduction was found to decrease down to about one third of Eg from a half. As to the device characteristics, we found that the threshold switching voltage (Vth) drastically decreased with the Sb content. These results, being accountable in terms of the changes in the bonding configuration of constituent atoms as well as in the electronic structure such as the energy gap and trap states, advance an effective method of compositional adjustment to modulate Vth of an OTS device for various applications. PMID:25403772

Pulse width modulation inverter with battery charger

DOEpatents

Slicker, James M.

1985-01-01

An inverter is connected between a source of DC power and a three-phase AC induction motor, and a microprocessor-based circuit controls the inverter using pulse width modulation techniques. In the disclosed method of pulse width modulation, both edges of each pulse of a carrier pulse train are equally modulated by a time proportional to sin .theta., where .theta. is the angular displacement of the pulse center at the motor stator frequency from a fixed reference point on the carrier waveform. The carrier waveform frequency is a multiple of the motor stator frequency. The modulated pulse train is then applied to each of the motor phase inputs with respective phase shifts of 120.degree. at the stator frequency. Switching control commands for electronic switches in the inverter are stored in a random access memory (RAM) and the locations of the RAM are successively read out in a cyclic manner, each bit of a given RAM location controlling a respective phase input of the motor. The DC power source preferably comprises rechargeable batteries and all but one of the electronic switches in the inverter can be disabled, the remaining electronic switch being part of a "flyback" DC-DC converter circuit for recharging the battery.

Pulse width modulation inverter with battery charger

NASA Technical Reports Server (NTRS)

Slicker, James M. (Inventor)

1985-01-01

An inverter is connected between a source of DC power and a three-phase AC induction motor, and a microprocessor-based circuit controls the inverter using pulse width modulation techniques. In the disclosed method of pulse width modulation, both edges of each pulse of a carrier pulse train are equally modulated by a time proportional to sin .theta., where .theta. is the angular displacement of the pulse center at the motor stator frequency from a fixed reference point on the carrier waveform. The carrier waveform frequency is a multiple of the motor stator frequency. The modulated pulse train is then applied to each of the motor phase inputs with respective phase shifts of 120.degree. at the stator frequency. Switching control commands for electronic switches in the inverter are stored in a random access memory (RAM) and the locations of the RAM are successively read out in a cyclic manner, each bit of a given RAM location controlling a respective phase input of the motor. The DC power source preferably comprises rechargeable batteries and all but one of the electronic switches in the inverter can be disabled, the remaining electronic switch being part of a flyback DC-DC converter circuit for recharging the battery.

Learning new sequential stepping patterns requires striatal plasticity during the earliest phase of acquisition.

PubMed

Nakamura, Toru; Nagata, Masatoshi; Yagi, Takeshi; Graybiel, Ann M; Yamamori, Tetsuo; Kitsukawa, Takashi

2017-04-01

Animals including humans execute motor behavior to reach their goals. For this purpose, they must choose correct strategies according to environmental conditions and shape many parameters of their movements, including their serial order and timing. To investigate the neurobiology underlying such skills, we used a multi-sensor equipped, motor-driven running wheel with adjustable sequences of foothold pegs on which mice ran to obtain water reward. When the peg patterns changed from a familiar pattern to a new pattern, the mice had to learn and implement new locomotor strategies in order to receive reward. We found that the accuracy of stepping and the achievement of water reward improved with the new learning after changes in the peg-pattern, and c-Fos expression levels assayed after the first post-switch session were high in both dorsolateral striatum and motor cortex, relative to post-switch plateau levels. Combined in situ hybridization and immunohistochemistry of striatal sections demonstrated that both enkephalin-positive (indirect pathway) neurons and substance P-positive (direct pathway) neurons were recruited specifically after the pattern switches, as were interneurons expressing neuronal nitric oxide synthase. When we blocked N-methyl-D-aspartate (NMDA) receptors in the dorsolateral striatum by injecting the NMDA receptor antagonist, D-2-amino-5-phosphonopentanoic acid (AP5), we found delays in early post-switch improvement in performance. These findings suggest that the dorsolateral striatum is activated on detecting shifts in environment to adapt motor behavior to the new context via NMDA-dependent plasticity, and that this plasticity may underlie forming and breaking skills and habits as well as to behavioral difficulties in clinical disorders. © 2017 Federation of European Neuroscience Societies and John Wiley & Sons Ltd.

Thermal annealing and transient electronic excitations induced interfacial and magnetic effects on Pt/Co/Pt trilayer

NASA Astrophysics Data System (ADS)

Sehdev, Neeru; Medwal, Rohit; Malik, Rakesh; Kandasami, Asokan; Kanjilal, Dinakar; Annapoorni, S.

2018-04-01

Present study investigates the importance of thermal annealing and transient electronic excitations (using 100 MeV oxygen ions) in assisting the interfacial atomic diffusion, alloy composition, and magnetic switching field distributions in Pt/Co/Pt stacked trilayer. X-ray diffraction analysis reveals that thermal annealing results in the formation of the face centered tetragonal L1°CoPt phase. The Rutherford back scattering spectra shows a trilayer structure for as-deposited and as-irradiated films. Interlayer mixing on the thermally annealed films further improves by electronic excitations produced by high energy ion irradiation. Magnetically hard face centered tetragonal CoPt alloy retains its hard phase after ion irradiation and reveals an enhancement in the structural ordering and magnetic stability. Enhancement in the homogeneity of alloy composition and its correlation with the magnetic switching field is evident from this study. A detailed investigation of the contributing parameters shows that the magnetic switching behaviour varies with the type of thermal annealing, transient electronic excitations of ion beams and combination of these processes.

Molecular quantum cellular automata cell design trade-offs: latching vs. power dissipation.

PubMed

Rahimi, Ehsan; Reimers, Jeffrey R

2018-06-20

The use of molecules to enact quantum cellular automata (QCA) cells has been proposed as a new way for performing electronic logic operations at sub-nm dimensions. A key question that arises concerns whether chemical or physical processes are to be exploited. The use of chemical reactions allows the state of a switch element to be latched in molecular form, making the output of a cell independent of its inputs, but costs energy to do the reaction. Alternatively, if purely electronic polarization is manipulated then no internal latching occurs, but no power is dissipated provided the fields from the inputs change slowly compared to the molecular response times. How these scenarios pan out is discussed by considering calculated properties of the 1,4-diallylbutane cation, a species often used as a paradigm for molecular electronic switching. Utilized are results from different calculation approaches that depict the ion either as a charge-localized mixed-valence compound functioning as a bistable switch, or else as an extremely polarizable molecule with a delocalized electronic structure. Practical schemes for using molecular cells in QCA and other devices emerge.

Application of Electron-Beam Controlled Diffuse Discharges to Fast Switching

DTIC Science & Technology

1983-06-01

pressure , switch area and length are estimated self-consistently for a given system efficiency is reviewed, The formalism is used to design a single pulse, 200 kV, 30 kA (6 omega) , 100 ns FWHM inductive storage generator.

Correct calibration procedure for the Q-switched ruby laser and checking the treatment irradiation pattern

PubMed Central

Ohshiro, Takafumi; Sasaki, Katsumi; Takenouchi, Kiyofumi; Kozuma, Mituaki; Ohshiro, Naoyuki; Kageyama, Yuichi

2013-01-01

Background and aims: There are many Q-switched lasers. The Q-switched ruby laser is the one most popularly used in dermatology, aesthetic surgery and plastic surgery, to remove pigmented lesions or tattoos. Correct and regular calibration of such a system is essential. However, some clinics fail to perform this with the excuse of having no measuring instrument (MI) in their offices or treatment rooms in some of their hospitals or clinics, or even the case of well-known medical universities in Japan. The present article explains the precise calibration procedure and beam pattern checking for the Q-switched ruby systems in the first author's clinic. Rationale: In the case of treatment with a medical laser, the calibration and the irradiated pattern (IP) check of the laser being used for treatment are the most important factors for treatment efficacy and safety. If these factors change, the treatment result could be different from that expected. Such kind of data are not acceptable as scientific information for a presentation or published paper. With such unreliable results and incorrect beam pattern, replicating such a study would be impossible Regular calibration check: In our clinic, we have 2 Q-switched ruby laser systems. On a daily basis, the beam patterns, both the optical axis of the beam and its treatment footprint, are checked on dedicated printed sheets and footprint paper, respectively, at the beginning of the day and after the last procedure. Every two weeks we calibrate our systems in-house using a precise MI. Every six months we calibrate the systems in-house with the MI, and then we send the systems back to the manufacturers for calibration. Once every year, we have our MI calibrated by an accredited facility in Japan. In this way, we are not only ensuring accurate and safe treatment for our patients, but we are also producing accurate system and treatment data which can be replicated by others, the basis of evidence-based medicine. PMID:24204090

pH-controlled silicon nanowires fluorescence switch

NASA Astrophysics Data System (ADS)

Mu, Lixuan; Shi, Wensheng; Zhang, Taiping; Zhang, Hongyan; She, Guangwei

2010-08-01

Covalently immobilizing photoinduced electronic transfer (PET) fluorophore 3-[N, N-bis(9-anthrylmethyl)amino]-propyltriethoxysilane (DiAN) on the surface of silicon nanowires (SiNWs) resulted a SiNWs-based fluorescence switch. This fluorescence switch is operated by adjustment of the acidity of the environment and exhibits sensitive response to pH at the range from 8 to 10. Such response is attributed to the effect of pH on the PET process. The successful combination of logic switch and SiNWs provides a rational approach to assemble different logic molecules on SiNWs for realization of miniaturization and modularization of switches and logic devices.

A ZnO nanowire resistive switch

NASA Astrophysics Data System (ADS)

Karthik, K. R. G.; Ramanujam Prabhakar, Rajiv; Hai, L.; Batabyal, Sudip K.; Huang, Y. Z.; Mhaisalkar, S. G.

2013-09-01

An individual ZnO nanowire resistive switch is evaluated with Pt/ZnO nanowire/Pt topology. A detailed DC I-V curve analysis is performed to bring both the conduction mechanism and the device characteristics to light. The device is further studied at various vacuum pressures to ascertain the presence of polar charges in ZnO nanowires as the phenomenon leading to the formation of the switch. The disappearance of the resistive switching is also analyzed with two kinds of fabrication approaches Focused Ion/Electron Beam involved in the making the device and a summary of both length and fabrication dependences of resistive switching in the ZnO nanowire is presented.

Chaotic electron diffusion through stochastic webs enhances current flow in superlattices.

PubMed

Fromhold, T M; Patanè, A; Bujkiewicz, S; Wilkinson, P B; Fowler, D; Sherwood, D; Stapleton, S P; Krokhin, A A; Eaves, L; Henini, M; Sankeshwar, N S; Sheard, F W

2004-04-15

Understanding how complex systems respond to change is of fundamental importance in the natural sciences. There is particular interest in systems whose classical newtonian motion becomes chaotic as an applied perturbation grows. The transition to chaos usually occurs by the gradual destruction of stable orbits in parameter space, in accordance with the Kolmogorov-Arnold-Moser (KAM) theorem--a cornerstone of nonlinear dynamics that explains, for example, gaps in the asteroid belt. By contrast, 'non-KAM' chaos switches on and off abruptly at critical values of the perturbation frequency. This type of dynamics has wide-ranging implications in the theory of plasma physics, tokamak fusion, turbulence, ion traps, and quasicrystals. Here we realize non-KAM chaos experimentally by exploiting the quantum properties of electrons in the periodic potential of a semiconductor superlattice with an applied voltage and magnetic field. The onset of chaos at discrete voltages is observed as a large increase in the current flow due to the creation of unbound electron orbits, which propagate through intricate web patterns in phase space. Non-KAM chaos therefore provides a mechanism for controlling the electrical conductivity of a condensed matter device: its extreme sensitivity could find applications in quantum electronics and photonics.

Monolithic control components for high power mm-waves

NASA Astrophysics Data System (ADS)

Armstrong, A.; Goodrich, J.; Moroney, W.; Wheeler, D.

1985-09-01

Monolithic PIN diode arrays are shown to provide significant advances in switching ratios, bandwidth, and high-power capability for millimeter control applications The PIN diodes are arranged in a series/parallel configuration and form an electronically controlled window for switching RF power by applying DC voltage. At Ka band, an SPST switch using the window array (WINAR) design typically has 0.6 dB insertion loss and 22 dB isolation over the 26.5 to 40.0 GHz band. The switch has over 500 W peak power and 25 W average power capability.

The role of the tunneling matrix element and nuclear reorganization in the design of quantum-dot cellular automata molecules

NASA Astrophysics Data System (ADS)

Henry, Jackson; Blair, Enrique P.

2018-02-01

Mixed-valence molecules provide an implementation for a high-speed, energy-efficient paradigm for classical computing known as quantum-dot cellular automata (QCA). The primitive device in QCA is a cell, a structure with multiple quantum dots and a few mobile charges. A single mixed-valence molecule can function as a cell, with redox centers providing quantum dots. The charge configuration of a molecule encodes binary information, and device switching occurs via intramolecular electron transfer between dots. Arrays of molecular cells adsorbed onto a substrate form QCA logic. Individual cells in the array are coupled locally via the electrostatic electric field. This device networking enables general-purpose computing. Here, a quantum model of a two-dot molecule is built in which the two-state electronic system is coupled to the dominant nuclear vibrational mode via a reorganization energy. This model is used to explore the effects of the electronic inter-dot tunneling (coupling) matrix element and the reorganization energy on device switching. A semi-classical reduction of the model also is made to investigate the competition between field-driven device switching and the electron-vibrational self-trapping. A strong electron-vibrational coupling (high reorganization energy) gives rise to self-trapping, which inhibits the molecule's ability to switch. Nonetheless, there remains an expansive area in the tunneling-reorganization phase space where molecules can support adequate tunneling. Thus, the relationship between the tunneling matrix element and the reorganization energy affords significant leeway in the design of molecules viable for QCA applications.

Concentration-dependent photophysical switching in mixed self-assembled monolayers of pentacene and perylenediimide on gold nanoclusters.

PubMed

Kato, Daiki; Sakai, Hayato; Araki, Yasuyuki; Wada, Takehiko; Tkachenko, Nikolai V; Hasobe, Taku

2018-03-28

Photophysical control and switching on organic-inorganic hybrid interfaces are of great interest in diverse fundamental and applicative research areas. 6,13-Bis(triisopropylsilylethynyl)pentacene (TP) is well-known to exhibit efficient singlet fission (SF) for generation of high-yield triplet excited states in aggregated forms, whereas perylenediimide (PDI) ensembles show the characteristic excimer formation. Additionally, a combination of pentacene (electron donor: D) and PDI (electron acceptor: A) is expected to undergo an efficient photoinduced electron transfer (PET), and absorption of two chromophores combined covers the entire visible region. Therefore, the concentration-dependent mixed self-assembled monolayers (SAMs) composed of two chromophores enable us to control and switch the photophysical processes on a surface. In this work, a series of mixed SAMs composed of TP and PDI units on gold nanoclusters (GNCs) were newly synthesized by changing the relative molecular concentration ratios. Structural control of mixed SAMs on a gold surface based on the concentration ratios was successfully achieved. Time-resolved femtosecond and nanosecond transient absorption measurements clearly demonstrate photophysical control and switching of the above competitive reactions such as SF, electron transfer (ET) and excimer formation. The maximum quantum yields of triplet states (ΦT = ∼170%) and electron transfer (ΦET = ∼95%) were quantitatively evaluated by changing the concentration ratios. The rate constants of SF and excimer processes are largely dependent on the concentration ratios, whereas the rate constants of ET processes approximately remain constant. These findings are also discussed based on the statistical framework of the assembly of chromophores on the gold surface.

Investigation of transient dynamics of capillary assisted particle assembly yield

NASA Astrophysics Data System (ADS)

Virganavičius, D.; Juodėnas, M.; Tamulevičius, T.; Schift, H.; Tamulevičius, S.

2017-06-01

In this paper, the transient behavior of the particle assembly yield dynamics when switching from low yield to high yield deposition at different velocity and thermal regimes is investigated. Capillary force assisted particle assembly (CAPA) using colloidal suspension of green fluorescent 270 nm diameter polystyrene beads was performed on patterned poly (dimethyl siloxane) substrates using a custom-built deposition setup. Two types of patterns with different trapping site densities were used to assess CAPA process dynamics and the influence of pattern density and geometry on the deposition yield transitions. Closely packed 300 nm diameter circular pits ordered in hexagonal arrangement with 300 nm pitch, and 2 × 2 mm2 square pits with 2 μm spacing were used. 2-D regular structures of the deposited particles were investigated by means of optical fluorescence and scanning electron microscopy. The fluorescence micrographs were analyzed using a custom algorithm enabling to identify particles and calculate efficiency of the deposition performed at different regimes. Relationship between the spatial distribution of particles in transition zone and ambient conditions was evaluated and quantified by approximation of the yield profile with a logistic function.

Selective Epitaxial Graphene Growth on SiC via AlN Capping

NASA Astrophysics Data System (ADS)

Zaman, Farhana; Rubio-Roy, Miguel; Moseley, Michael; Lowder, Jonathan; Doolittle, William; Berger, Claire; Dong, Rui; Meindl, James; de Heer, Walt; Georgia Institute of Technology Team

2011-03-01

Electronic-quality graphene is epitaxially grown by graphitization of carbon-face silicon carbide (SiC) by the sublimation of silicon atoms from selected regions uncapped by aluminum nitride (AlN). AlN (deposited by molecular beam epitaxy) withstands high graphitization temperatures of 1420o C, hence acting as an effective capping layer preventing the growth of graphene under it. The AlN is patterned and etched to open up windows onto the SiC surface for subsequent graphitization. Such selective epitaxial growth leads to the formation of high-quality graphene in desired patterns without the need for etching and lithographic patterning of graphene itself. No detrimental contact of the graphene with external chemicals occurs throughout the fabrication-process. The impact of process-conditions on the mobility of graphene is investigated. Graphene hall-bars were fabricated and characterized by scanning Raman spectroscopy, ellipsometry, and transport measurements. This controlled growth of graphene in selected regions represents a viable approach to fabrication of high-mobility graphene as the channel material for fast-switching field-effect transistors.

Thin, nearly wireless adaptive optical device

NASA Technical Reports Server (NTRS)

Knowles, Gareth (Inventor); Hughes, Eli (Inventor)

2008-01-01

A thin, nearly wireless adaptive optical device capable of dynamically modulating the shape of a mirror in real time to compensate for atmospheric distortions and/or variations along an optical material is provided. The device includes an optical layer, a substrate, at least one electronic circuit layer with nearly wireless architecture, an array of actuators, power electronic switches, a reactive force element, and a digital controller. Actuators are aligned so that each axis of expansion and contraction intersects both substrate and reactive force element. Electronics layer with nearly wireless architecture, power electronic switches, and digital controller are provided within a thin-film substrate. The size and weight of the adaptive optical device is solely dominated by the size of the actuator elements rather than by the power distribution system.

Thin, nearly wireless adaptive optical device

NASA Technical Reports Server (NTRS)

Knowles, Gareth (Inventor); Hughes, Eli (Inventor)

2007-01-01

A thin, nearly wireless adaptive optical device capable of dynamically modulating the shape of a mirror in real time to compensate for atmospheric distortions and/or variations along an optical material is provided. The device includes an optical layer, a substrate, at least one electronic circuit layer with nearly wireless architecture, an array of actuators, power electronic switches, a reactive force element, and a digital controller. Actuators are aligned so that each axis of expansion and contraction intersects both substrate and reactive force element. Electronics layer with nearly wireless architecture, power electronic switches, and digital controller are provided within a thin-film substrate. The size and weight of the adaptive optical device is solely dominated by the size of the actuator elements rather than by the power distribution system.

Thin nearly wireless adaptive optical device

NASA Technical Reports Server (NTRS)

Knowles, Gareth J. (Inventor); Hughes, Eli (Inventor)

2009-01-01

A thin nearly wireless adaptive optical device capable of dynamically modulating the shape of a mirror in real time to compensate for atmospheric distortions and/or variations along an optical material is provided. The device includes an optical layer, a substrate, at least one electronic circuit layer with nearly wireless architecture, an array of actuators, power electronic switches, a reactive force element, and a digital controller. Actuators are aligned so that each axis of expansion and contraction intersects both substrate and reactive force element. Electronics layer with nearly wireless architecture, power electronic switches, and digital controller are provided within a thin-film substrate. The size and weight of the adaptive optical device is solely dominated by the size of the actuator elements rather than by the power distribution system.

Realization of all-optical switch and diode via Raman gain process using a Kerr field

NASA Astrophysics Data System (ADS)

Abbas, Muqaddar; Qamar, Sajid; Qamar, Shahid

2016-08-01

The idea of optical photonic crystal, which is generated using two counter-propagating fields, is revisited to study gain-assisted all-optical switch and diode using Kerr field. Two counter-propagating fields with relative detuning Δ ν generate standing-wave field pattern which interacts with a four-level atomic system. The standing-wave field pattern acts like a static photonic crystal for Δ ν =0 , however, it behaves as a moving photonic crystal for Δ ν \

Impact Sensors for Use with Electronic Fuzes

DTIC Science & Technology

1975-12-01

corroborated the major features of a theoretical analysis. More work is needed to 10R. Wasser , Impact Switch Tests, US Naval Ordnance...might be more fruitful if more effort were expended on electro- mechanical systems. One principle that could be applied to such a l0R. Wasser ...Switches for Artillery Fuzes, Part I: Development, Harry Diamond Laboratories TM-72-18 (July 1972). (10) R. Wasser , Impact Switch TestP, US Naval

On the size-dependent magnetism and all-optical magnetization switching of transition-metal silicide nanostructures

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

Glushkov, G. I.; Tuchin, A. V.; Popov, S. V.

Theoretical investigations of the electronic structure, synthesis, and all-optical magnetization switching of transition-metal silicide nanostructures are reported. The magnetic moment of the nanostructures is studied as a function of the silicide cluster size and configuration. The experimentally demonstrated magnetization switching of nanostructured nickel silicide by circularly polarized light makes it possible to create high-speed storage devices with high density data recording.

High On/Off Ratio Memristive Switching of Manganite/Cuprate Bilayer by Interfacial Magnetoelectricity

DOE PAGES

Shen, Xiao; Pennycook, Timothy J.; Hernandez-Martin, David; ...

2016-05-27

Memristive switching serves as the basis for a new generation of electronic devices. Conventional memristors are two-terminal devices in which the current is turned on and off by redistributing point defects, e.g., vacancies. Memristors based on alternative mechanisms have been explored, but achieving both high on/off ratio and low switching energy, as needed in applications, remains a challenge. This paper reports memristive switching in La 0.7Ca 0.3MnO 3/PrBa 2Cu 3O 7 bilayers with an on/off ratio greater than 103 and results of density functional theory calculations in terms of which it is concluded that the phenomenon is likely the resultmore » of a new type of interfacial magnetoelectricity. More specifically, this study shows that an external electric field induces subtle displacements of the interfacial Mn ions, which switches on/off an interfacial magnetic “dead layer”, resulting in memristive behavior for spin-polarized electron transport across the bilayer. The interfacial nature of the switching entails low energy cost, about of a tenth of atto Joule for writing/erasing a “bit”. To conclude, the results indicate new opportunities for manganite/cuprate systems and other transition metal oxide junctions in memristive applications.« less

Command, Control, Communications, Computers, Intelligence Electronic Warfare (C4IEW) and Sensors. Project Book. Fiscal Year 1996

DTIC Science & Technology

1996-01-01

INTENSIFICATION (AI2) ATD AERIAL SCOUT SENSORS INTEGRATION (ASSI) BISTATIC RADAR FOR WEAPONS LOCATION (BRWL) ATD CLOSE IN MAN PORTABLE MINE DETECTOR (CIMMD...MS IV PE & LINE #: 1X428010.D107 HI Operations/Support DESCRIPTION: The AN/TTC-39A Circuit Switch is a 744 line mobile , automatic ...SYNOPSIS: AN/TTC-39 IS A MOBILE , AUTOMATIC , MODULAR ELECTRONIC CIRCUIT SWITCH UNDER PROCESSOR CONTROL WITH INTEGRAL COMSEC AND MULTIPLEX EQUIPMENT. AN/TTC

MULTIPLIER CIRCUIT

DOEpatents

Chase, R.L.

1963-05-01

An electronic fast multiplier circuit utilizing a transistor controlled voltage divider network is presented. The multiplier includes a stepped potentiometer in which solid state or transistor switches are substituted for mechanical wipers in order to obtain electronic switching that is extremely fast as compared to the usual servo-driven mechanical wipers. While this multiplier circuit operates as an approximation and in steps to obtain a voltage that is the product of two input voltages, any desired degree of accuracy can be obtained with the proper number of increments and adjustment of parameters. (AEC)

Emergence of electron coherence and two-color all-optical switching in MoS2 based on spatial self-phase modulation

PubMed Central

Wu, Yanling; Wu, Qiong; Sun, Fei; Cheng, Cai; Meng, Sheng; Zhao, Jimin

2015-01-01

Generating electron coherence in quantum materials is essential in optimal control of many-body interactions and correlations. In a multidomain system this signifies nonlocal coherence and emergence of collective phenomena, particularly in layered 2D quantum materials possessing novel electronic structures and high carrier mobilities. Here we report nonlocal ac electron coherence induced in dispersed MoS2 flake domains, using coherent spatial self-phase modulation (SSPM). The gap-dependent nonlinear dielectric susceptibility χ(3) measured is surprisingly large, where direct interband transition and two-photon SSPM are responsible for excitations above and below the bandgap, respectively. A wind-chime model is proposed to account for the emergence of the ac electron coherence. Furthermore, all-optical switching is achieved based on SSPM, especially with two-color intraband coherence, demonstrating that electron coherence generation is a ubiquitous property of layered quantum materials. PMID:26351696

A 1-2 GHz pulsed and continuous wave electron paramagnetic resonance spectrometer

NASA Astrophysics Data System (ADS)

Quine, Richard W.; Rinard, George A.; Ghim, Barnard T.; Eaton, Sandra S.; Eaton, Gareth R.

1996-07-01

A microwave bridge has been constructed that performs three types of electron paramagnetic resonance experiments: continuous wave, pulsed saturation recovery, and pulsed electron spin echo. Switching between experiment types can be accomplished via front-panel switches without moving the sample. Design features and performance of the bridge and of a resonator used in testing the bridge are described. The bridge is constructed of coaxial components connected with semirigid cable. Particular attention has been paid to low-noise design of the preamplifier and stability of automatic frequency control circuits. The bridge incorporates a Smith chart display and phase adjustment meter for ease of tuning.

Quinonoid metal complexes: toward molecular switches.

PubMed

Dei, Andrea; Gatteschi, Dante; Sangregorio, Claudio; Sorace, Lorenzo

2004-11-01

The peculiar redox-active character of quinonoid metal complexes makes them extremely appealing to design materials of potential technological interest. We show here how the tuning of the properties of these systems can be pursued by using appropriate molecular synthetic techniques. In particular, we focus our attention on metal polyoxolene complexes exhibiting intramolecular electron transfer processes involving either the ligand and the metal ion or the two dioxolene moieties of a properly designed ligand thus inducing electronic bistability. The transition between the two metastable electronic states can be induced by different external stimuli such as temperature, pressure, light, or pH suggesting the use of these systems for molecular switches.

Electronic switching spherical array antenna

NASA Technical Reports Server (NTRS)

Stockton, R.

1978-01-01

This work was conducted to demonstrate the performance levels attainable with an ESSA (Electronic Switching Spherical Array) antenna by designing and testing an engineering model. The antenna was designed to satisfy general spacecraft environmental requirements and built to provide electronically commandable beam pointing capability throughout a hemisphere. Constant gain and beam shape throughout large volumetric coverage regions are the principle characteristics. The model is intended to be a prototype of a standard communications and data handling antenna for user scientific spacecraft with the Tracking and Data Relay Satellite System (TDRSS). Some additional testing was conducted to determine the feasibility of an integrated TDRSS and GPS (Global Positioning System) antenna system.

Research on fault characteristics about switching component failures for distribution electronic power transformers

NASA Astrophysics Data System (ADS)

Sang, Z. X.; Huang, J. Q.; Yan, J.; Du, Z.; Xu, Q. S.; Lei, H.; Zhou, S. X.; Wang, S. C.

2017-11-01

The protection is an essential part for power device, especially for those in power grid, as the failure may cost great losses to the society. A study on the voltage and current abnormality in the power electronic devices in Distribution Electronic Power Transformer (D-EPT) during the failures on switching components is presented, as well as the operational principles for 10 kV rectifier, 10 kV/400 V DC-DC converter and 400 V inverter in D-EPT. Derived from the discussion on the effects of voltage and current distortion, the fault characteristics as well as a fault diagnosis method for D-EPT are introduced.

Photoconductive Switching of a Blumlein Pulser

DTIC Science & Technology

1987-06-01

Diamond Laboratories Adelphi, Maryland 20783 Lawrence J. Bovino U. S. Army LABCOM Electronics Technology and Devices Laboratory Fort Monmouth, New... Bovino , T. Burke, R. Youmans, M. Weiner and J. Carter, "Recent Advances in Optically Controlled Bulk Semicon- ductor switches," in Proceedings of

Tuning a circular p-n junction in graphene from quantum confinement to optical guiding

NASA Astrophysics Data System (ADS)

Jiang, Yuhang; Mao, Jinhai; Moldovan, Dean; Masir, Massoud Ramezani; Li, Guohong; Watanabe, Kenji; Taniguchi, Takashi; Peeters, Francois M.; Andrei, Eva Y.

2017-11-01

The photon-like propagation of the Dirac electrons in graphene, together with its record-high electronic mobility, can lead to applications based on ultrafast electronic response and low dissipation. However, the chiral nature of the charge carriers that is responsible for the high mobility also makes it difficult to control their motion and prevents electronic switching. Here, we show how to manipulate the charge carriers by using a circular p-n junction whose size can be continuously tuned from the nanometre to the micrometre scale. The junction size is controlled with a dual-gate device consisting of a planar back gate and a point-like top gate made by decorating a scanning tunnelling microscope tip with a gold nanowire. The nanometre-scale junction is defined by a deep potential well created by the tip-induced charge. It traps the Dirac electrons in quantum-confined states, which are the graphene equivalent of the atomic collapse states (ACSs) predicted to occur at supercritically charged nuclei. As the junction size increases, the transition to the optical regime is signalled by the emergence of whispering-gallery modes, similar to those observed at the perimeter of acoustic or optical resonators, and by the appearance of a Fabry-Pérot interference pattern for junctions close to a boundary.

Electron diffraction covering a wide angular range from Bragg diffraction to small-angle diffraction.

PubMed

Nakajima, Hiroshi; Kotani, Atsuhiro; Harada, Ken; Mori, Shigeo

2018-04-09

We construct an electron optical system to investigate Bragg diffraction (the crystal lattice plane, 10-2 to 10-3 rad) with the objective lens turned off by adjusting the current in the intermediate lenses. A crossover was located on the selected-area aperture plane. Thus, the dark-field imaging can be performed by using a selected-area aperture to select Bragg diffraction spots. The camera length can be controlled in the range of 0.8-4 m without exciting the objective lens. Furthermore, we can observe the magnetic-field dependence of electron diffraction using the objective lens under weak excitation conditions. The diffraction mode for Bragg diffraction can be easily switched to a small-angle electron diffraction mode having a camera length of more than 100 m. We propose this experimental method to acquire electron diffraction patterns that depict an extensive angular range from 10-2 to 10-7 rad. This method is applied to analyze the magnetic microstructures in three distinct magnetic materials, i.e. a uniaxial magnetic structure of BaFe10.35Sc1.6Mg0.05O19, a martensite of a Ni-Mn-Ga alloy, and a helical magnetic structure of Ba0.5Sr1.5Zn2Fe12O22.

Development and simulation study of a new inverse-pinch high Coulomb transfer switch

NASA Technical Reports Server (NTRS)

Choi, Sang H.

1989-01-01

The inverse-pinch plasma switch was studied using a computer simulation code. The code was based on a 2-D, 2-temperature magnetohydrodynamic (MHD) model. The application of this code was limited to the disk-type inverse-pinch plasma switch. The results of the computer analysis appear to be in agreement with the experimental results when the same parameters are used. An inverse-pinch plasma switch for closing has been designed and tested for high-power switching requirements. An azimuthally uniform initiation of breakdown is a key factor in achieving an inverse-pinch current path in the switch. Thus, various types of triggers, such as trigger pins, wire-brush, ring trigger, and hypocycloidal-pinch (HCP) devices have been tested for uniform breakdown. Recently, triggering was achieved by injection of a plasma-ring (plasma puff) that is produced separately with hypocycloidal-pinch electrodes placed under the cathode of the main gap. The current paths at switch closing, initiated by the injection of a plasma-ring from the HCP trigger are azimuthally uniform, and the local current density is significantly reduced, so that damage to the electrodes and the insulator surfaces is minimized. The test results indicate that electron bombardment on the electrodes and the insulator surfaces is minimized. The test results indicate that electron bombardment on the electrodes is four orders of magnitude less than that of a spark-gap switch for the same switching power. Indeed, a few thousand shots with peak current exceeding a mega-ampere and with hold-off voltage up to 20 kV have been conducted without showing measurable damage to the electrodes and insulators.

Effects Of Environmental And Operational Stresses On RF MEMS Switch Technologies For Space Applications

NASA Technical Reports Server (NTRS)

Jah, Muzar; Simon, Eric; Sharma, Ashok

2003-01-01

Micro Electro Mechanical Systems (MEMS) have been heralded for their ability to provide tremendous advantages in electronic systems through increased electrical performance, reduced power consumption, and higher levels of device integration with a reduction of board real estate. RF MEMS switch technology offers advantages such as low insertion loss (0.1- 0.5 dB), wide bandwidth (1 GHz-100 GHz), and compatibility with many different process technologies (quartz, high resistivity Si, GaAs) which can replace the use of traditional electronic switches, such as GaAs FETS and PIN Diodes, in microwave systems for low signal power (x < 500 mW) applications. Although the electrical characteristics of RF MEMS switches far surpass any existing technologies, the unknown reliability, due to the lack of information concerning failure modes and mechanisms inherent to MEMS devices, create an obstacle to insertion of MEMS technology into high reliability applications. All MEMS devices are sensitive to moisture and contaminants, issues easily resolved by hermetic or near-hermetic packaging. Two well-known failure modes of RF MEMS switches are charging in the dielectric layer of capacitive membrane switches and contact interface stiction of metal-metal switches. Determining the integrity of MEMS devices when subjected to the shock, vibration, temperature extremes, and radiation of the space environment is necessary to facilitate integration into space systems. This paper will explore the effects of different environmental stresses, operational life cycling, temperature, mechanical shock, and vibration on the first commercially available RF MEMS switches to identify relevant failure modes and mechanisms inherent to these device and packaging schemes for space applications. This paper will also describe RF MEMS Switch technology under development at NASA GSFC.

Lineage tracing of human B cells reveals the in vivo landscape of human antibody class switching

PubMed Central

Horns, Felix; Vollmers, Christopher; Croote, Derek; Mackey, Sally F; Swan, Gary E; Dekker, Cornelia L; Davis, Mark M; Quake, Stephen R

2016-01-01

Antibody class switching is a feature of the adaptive immune system which enables diversification of the effector properties of antibodies. Even though class switching is essential for mounting a protective response to pathogens, the in vivo patterns and lineage characteristics of antibody class switching have remained uncharacterized in living humans. Here we comprehensively measured the landscape of antibody class switching in human adult twins using antibody repertoire sequencing. The map identifies how antibodies of every class are created and delineates a two-tiered hierarchy of class switch pathways. Using somatic hypermutations as a molecular clock, we discovered that closely related B cells often switch to the same class, but lose coherence as somatic mutations accumulate. Such correlations between closely related cells exist when purified B cells class switch in vitro, suggesting that class switch recombination is directed toward specific isotypes by a cell-autonomous imprinted state. DOI: http://dx.doi.org/10.7554/eLife.16578.001 PMID:27481325

Nonuniform traffic spots (NUTS) in multistage interconnection networks

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

Lang, T.; Kurisaki, L.

1990-09-01

The performance of multistage interconnection networks for multiprocessors is degraded when the traffic pattern produces nonuniform congestion in the blocking switches, that is, when there exist nonuniform traffic spots. For some specific patterns the authors evaluate this degradation in performance and propose modifications to the network organization and operation to reduce the degradation. Successful modifications are the use of diverting switches and the extension of the network with additional links. The use of these modifications makes the network more effective for a larger variety of traffic patterns. The authors also consider the case in which the network carries the superpositionmore » of two types of traffic. One type is the high throughput data and instruction traffic, while the other consists of control and I/O packets which are of low throughput but have severe real-time constraints. The authors conclude that diverting switches and networks with additional links are also suitable for assuring low latency for the real-time traffic, especially when using the displacing mode.« less

Studies of ZVS soft switching of dual-active-bridge isolated bidirectional DC-DC converters

NASA Astrophysics Data System (ADS)

Xu, Fei; Zhao, Feng; Shi, Qibiao; Wen, Xuhui

2018-05-01

To operate dual-active-bridge isolated bidirectional dc- dc converter (DAB) at high efficiency, the two bridge switches must operate with Zero-Voltage-Switching (ZVS) over as wide an operating range as possible. This paper proposes a new perspective on realizing ZVS in dead-time. An exact theoretical analysis and mathematical mode is built to explain the process of ZVS switching in dead-time under Single Phase Shift (SPS) control strategy. In order to assure the two bridge switches operate on soft switching, every SPS switching point is analyzed. Generally, dead-time will be determined when the power electronic devices is selected. The key factor to realizing ZVS is the size of the end time of resonance comparing to dead-time. Through detailed analysis, it can obtain the conditions of all switches achieving ZVS turn-on and turn-off. Finally, simulation validates the theoretical analysis and some advice are given to realize the ZVS soft switching.

An Advanced Electrospinning Method of Fabricating Nanofibrous Patterned Architectures with Controlled Deposition and Desired Alignment

NASA Astrophysics Data System (ADS)

Rasel, Sheikh Md

We introduce a versatile advanced method of electrospinning for fabricating various kinds of nanofibrous patterns along with desired alignment, controlled amount of deposition and locally variable density into the architectures. In this method, we employed multiple electrodes whose potentials have been altered in milliseconds with the help of microprocessor based control system. Therefore, key success of this method was that the electrical field as well as charge carrying fibers could be switched shortly from one electrode's location to another, as a result, electrospun fibers could be deposited on the designated areas with desired alignment. A wide range of nanofibrous patterned architectures were constructed using proper arrangement of multiple electrodes. By controlling the concurrent activation time of two adjacent electrodes, we demonstrated that amount of fibers going into the pattern can be adjusted and desired alignment in electrospun fibers can be obtained. We also revealed that the deposition density of electrospun fibers in different areas of patterned architectures can be varied. We showed that by controlling the deposition time between two adjacent electrodes, a number of functionally graded patterns can be generated with uniaxial alignment. We also demonstrated that this handy method was capable of producing random, aligned, and multidirectional nanofibrous mats by engaging a number of electrodes and switching them in desired patterns. A comprehensive study using finite element method was carried out to understand the effects of electrical field. Simulation results revealed that electrical field strength alters shortly based on electrode control switch patterns. Nanofibrous polyvinyl alcohol (PVA) scaffolds and its composite reinforced with wollastonite and wood flour were fabricated using rotating drum electrospinning technique. Morphological, mechanical, and thermal, properties were characterized on PVA/wollastonite and PVA/wood flour nanocomposites containing 0, 5, 10, and 20 wt % of fillers. Morphological analyses carried out by digital optical microscope, scanning electron microscopy, x-ray computed tomography, and Fourier transform infrared spectroscopy, confirmed the presence and well dispersion of fillers in the composites. In addition, improvement of mechanical properties with increased filler content further emphasized the adhesion between matrix and reinforcement. PVA with 20 wt % wollastonite composite exhibited the highest tensile strength (11.99 MPa) and tensile module (198 MPa) as compared to pure PVA (3.92 MPa and 83 MPa, respectively). Moreover, the thermal tests demonstrated that there is no major deviation in the thermal stability due to the addition of wollastonite in PVA scaffolds. Almost similar trend was observed in PVA/wood flour nanocomposites where tensile strength improved by 228 % for 20 wt % of reinforcement. The PVA/wollastonite and PVA/wood flour fibrous nanocomposite which poses higher mechanical properties might be potentially suitable for many advanced applications such as filtration, tissue engineering, and food processing. We believe this study will contribute to further scientific understanding of the patterning mechanism of electrospun nanofibers and to allow for variety of design of specific patterned nanofibrous architectures with desired functional properties. Therefore, this improved scheme of electrospinning can have significant impact in a broad range of applications including tissue engineering scaffolds, filtrations, and nanoelectronics.

First-order metal-insulator transitions in vanadates from first principles

NASA Astrophysics Data System (ADS)

Kumar, Anil; Rabe, Karin

2013-03-01

Materials that exhibit first-order metal-insulator transitions, with the accompanying abrupt change in the conductivity, have potential applications as switches in future electronic devices. Identification of materials and exploration of the atomic-scale mechanisms for switching between the two electronic states is a focus of current research. In this work, we search for first-order metal-insulator transitions in transition metal compounds, with a particular focus on d1 and d2 systems, by using first principles calculations to screen for an alternative low-energy state having not only a electronic character opposite to that of the ground state, but a distinct structure and/or magnetic ordering which would permit switching by an applied field or stress. We will present the results of our investigation of the perovskite compounds SrVO3, LaVO3, CaVO3, YVO3, LaTiO3 and related layered phase, including superlattices and Ruddlesden-Popper phases. While the pure compounds do not satisfy the search criteria, the layered phases show promising results.

Probing the electrical switching of a memristive optical antenna by STEM EELS

PubMed Central

Schoen, David T.; Holsteen, Aaron L.; Brongersma, Mark L.

2016-01-01

The scaling of active photonic devices to deep-submicron length scales has been hampered by the fundamental diffraction limit and the absence of materials with sufficiently strong electro-optic effects. Plasmonics is providing new opportunities to circumvent this challenge. Here we provide evidence for a solid-state electro-optical switching mechanism that can operate in the visible spectral range with an active volume of less than (5 nm)3 or ∼10−6 λ3, comparable to the size of the smallest electronic components. The switching mechanism relies on electrochemically displacing metal atoms inside the nanometre-scale gap to electrically connect two crossed metallic wires forming a cross-point junction. These junctions afford extreme light concentration and display singular optical behaviour upon formation of a conductive channel. The active tuning of plasmonic antennas attached to such junctions is analysed using a combination of electrical and optical measurements as well as electron energy loss spectroscopy in a scanning transmission electron microscope. PMID:27412052

Transparent resistive switching memory using aluminum oxide on a flexible substrate

NASA Astrophysics Data System (ADS)

Yeom, Seung-Won; Shin, Sang-Chul; Kim, Tan-Young; Ha, Hyeon Jun; Lee, Yun-Hi; Shim, Jae Won; Ju, Byeong-Kwon

2016-02-01

Resistive switching memory (ReRAM) has attracted much attention in recent times owing to its fast switching, simple structure, and non-volatility. Flexible and transparent electronic devices have also attracted considerable attention. We therefore fabricated an Al2O3-based ReRAM with transparent indium-zinc-oxide (IZO) electrodes on a flexible substrate. The device transmittance was found to be higher than 80% in the visible region (400-800 nm). Bended states (radius = 10 mm) of the device also did not affect the memory performance because of the flexibility of the two transparent IZO electrodes and the thin Al2O3 layer. The conduction mechanism of the resistive switching of our device was explained by ohmic conduction and a Poole-Frenkel emission model. The conduction mechanism was proved by oxygen vacancies in the Al2O3 layer, as analyzed by x-ray photoelectron spectroscopy analysis. These results encourage the application of ReRAM in flexible and transparent electronic devices.

Two-Phase Thermal Switching System for a Small, Extended Duration Lunar Science Platform

NASA Technical Reports Server (NTRS)

Bugby, D.; Farmer, J.; OConnor, B.; Wirzburger, M.; Abel, E.; Stouffer, C.

2010-01-01

Issue: extended duration lunar science platforms, using solar/battery or radioisotope power, require thermal switching systems that: a) Provide efficient cooling during the 15-earth-day 390 K lunar day; b) Consume minimal power during the 15-earth-day 100 K lunar night. Objective: carry out an analytical study of thermal switching systems that can meet the thermal requirements of: a) International Lunar Network (ILN) anchor node mission - primary focus; b) Other missions such as polar crater landers. ILN Anchor Nodes: network of geophysical science platforms to better understand the interior structure/composition of the moon: a) Rationale: no data since Apollo seismic stations ceased operation in 1977; b) Anchor Nodes: small, low-power, long-life (6-yr) landers with seismographic and a few other science instruments (see next chart); c) WEB: warm electronics box houses ILN anchor node electronics/batteries. Technology Need: thermal switching system that will keep the WEB cool during the lunar day and warm during the lunar night.

Carrier Density Modulation in Ge Heterostructure by Ferroelectric Switching

DOE PAGES

Ponath, Patrick; Fredrickson, Kurt; Posadas, Agham B.; ...

2015-01-14

The development of nonvolatile logic through direct coupling of spontaneous ferroelectric polarization with semiconductor charge carriers is nontrivial, with many issues, including epitaxial ferroelectric growth, demonstration of ferroelectric switching, and measurable semiconductor modulation. Here we report a true ferroelectric field effect carrier density modulation in an underlying Ge(001) substrate by switching of the ferroelectric polarization in the epitaxial c-axis-oriented BaTiO3 (BTO) grown by molecular beam epitaxy (MBE) on Ge. Using density functional theory, we demonstrate that switching of BTO polarization results in a large electric potential change in Ge. Aberration-corrected electron microscopy confirms the interface sharpness, and BTO tetragonality. Electron-energy-lossmore » spectroscopy (EELS) indicates the absence of any low permittivity interlayer at the interface with Ge. Using piezoelectric force microscopy (PFM), we confirm the presence of fully switchable, stable ferroelectric polarization in BTO that appears to be single domain. Using microwave impedance microscopy (MIM), we clearly demonstrate a ferroelectric field effect.« less

Domains in Ferroelectric Nanostructures

NASA Astrophysics Data System (ADS)

Gregg, Marty

2010-03-01

Ferroelectric materials have great potential in influencing the future of small scale electronics. At a basic level, this is because ferroelectric surfaces are charged, and so interact strongly with charge-carrying metals and semiconductors - the building blocks for all electronic systems. Since the electrical polarity of the ferroelectric can be reversed, surfaces can both attract and repel charges in nearby materials, and can thereby exert complete control over both charge distribution and movement. It should be no surprise, therefore, that microelectronics industries have already looked very seriously at harnessing ferroelectric materials in a variety of applications, from solid state memory chips (FeRAMs) to field effect transistors (FeFETs). In all such applications, switching the direction of the polarity of the ferroelectric is a key aspect of functional behavior. The mechanism for switching involves the field-induced nucleation and growth of domains. Domain coarsening, through domain wall propagation, eventually causes the entire ferroelectric to switch its polar direction. It is thus the existence and behavior of domains that determine the switching response, and ultimately the performance of the ferroelectric device. A major issue, associated with the integration of ferroelectrics into microelectronic devices, has been that the fundamental properties associated with ferroelectrics, when in bulk form, appear to change quite dramatically and unpredictably when at the nanoscale: new modes of behaviour, and different functional characteristics from those seen in bulk appear. For domains, in particular, the proximity of surfaces and boundaries have a dramatic effect: surface tension and depolarizing fields both serve to increase the equilibrium density of domains, such that minor changes in scale or morphology can have major ramifications for domain redistribution. Given the importance of domains in dictating the overall switching characteristics of a device, the need to fully understand how size and morphology affect domain behaviour in small scale ferroelectrics is obvious. In this talk, observations from a programme of study examining domains in meso and nano-scale BaTiO3 shapes, that have been cut directly from bulk single crystal using focused ion beam milling, will be presented. In general, the equilibrium static domain configurations that occur appear to be the result of a simultaneous desire to minimize both the macroscopic strain and depolarizing fields developed on cooling through the Curie Temperature. While such governing factors might be obvious, the specific patterns that result as a function of morphology are often non-intuitive, and a series of images of domains in nanodots, rods and wires will be presented and rationalised. In addition, the nature in which morphological factors influence domain dynamics during switching will be discussed, with particular focus on axial switching in nanowires, and the manner in which local surface perturbations (such as notches and antinotches) affect domain wall propagation. In collaboration with Alina Schilling, Li-Wu Chang, Mark McMillen, Raymond McQuaid, and Leo McGilly, Queen's University Belfast; Gustau Catalan, Universitat Autonoma de Barcelona; and James Scott, University of Cambridge.

Unique Flexibility in Energy Metabolism Allows Mycobacteria to Combat Starvation and Hypoxia

PubMed Central

Berney, Michael; Cook, Gregory M.

2010-01-01

Mycobacteria are a group of obligate aerobes that require oxygen for growth, but paradoxically have the ability to survive and metabolize under hypoxia. The mechanisms responsible for this metabolic plasticity are unknown. Here, we report on the adaptation of Mycobacterium smegmatis to slow growth rate and hypoxia using carbon-limited continuous culture. When M. smegmatis is switched from a 4.6 h to a 69 h doubling time at a constant oxygen saturation of 50%, the cells respond through the down regulation of respiratory chain components and the F1Fo-ATP synthase, consistent with the cells lower demand for energy at a reduced growth rate. This was paralleled by an up regulation of molecular machinery that allowed more efficient energy generation (i.e. Complex I) and the use of alternative electron donors (e.g. hydrogenases and primary dehydrogenases) to maintain the flow of reducing equivalents to the electron transport chain during conditions of severe energy limitation. A hydrogenase mutant showed a 40% reduction in growth yield highlighting the importance of this enzyme in adaptation to low energy supply. Slow growing cells at 50% oxygen saturation subjected to hypoxia (0.6% oxygen saturation) responded by switching on oxygen scavenging cytochrome bd, proton-translocating cytochrome bc1-aa3 supercomplex, another putative hydrogenase, and by substituting NAD+-dependent enzymes with ferredoxin-dependent enzymes thus highlighting a new pattern of mycobacterial adaptation to hypoxia. The expression of ferredoxins and a hydrogenase provides a potential conduit for disposing of and transferring electrons in the absence of exogenous electron acceptors. The use of ferredoxin-dependent enzymes would allow the cell to maintain a high carbon flux through its central carbon metabolism independent of the NAD+/NADH ratio. These data demonstrate the remarkable metabolic plasticity of the mycobacterial cell and provide a new framework for understanding their ability to survive under low energy conditions and hypoxia. PMID:20062806

Molecular Rotors as Switches

PubMed Central

Xue, Mei; Wang, Kang L.

2012-01-01

The use of a functional molecular unit acting as a state variable provides an attractive alternative for the next generations of nanoscale electronics. It may help overcome the limits of conventional MOSFETd due to their potential scalability, low-cost, low variability, and highly integratable characteristics as well as the capability to exploit bottom-up self-assembly processes. This bottom-up construction and the operation of nanoscale machines/devices, in which the molecular motion can be controlled to perform functions, have been studied for their functionalities. Being triggered by external stimuli such as light, electricity or chemical reagents, these devices have shown various functions including those of diodes, rectifiers, memories, resonant tunnel junctions and single settable molecular switches that can be electronically configured for logic gates. Molecule-specific electronic switching has also been reported for several of these device structures, including nanopores containing oligo(phenylene ethynylene) monolayers, and planar junctions incorporating rotaxane and catenane monolayers for the construction and operation of complex molecular machines. A specific electrically driven surface mounted molecular rotor is described in detail in this review. The rotor is comprised of a monolayer of redox-active ligated copper compounds sandwiched between a gold electrode and a highly-doped P+ Si. This electrically driven sandwich-type monolayer molecular rotor device showed an on/off ratio of approximately 104, a read window of about 2.5 V, and a retention time of greater than 104 s. The rotation speed of this type of molecular rotor has been reported to be in the picosecond timescale, which provides a potential of high switching speed applications. Current-voltage spectroscopy (I-V) revealed a temperature-dependent negative differential resistance (NDR) associated with the device. The analysis of the device I–V characteristics suggests the source of the observed switching effects to be the result of the redox-induced ligand rotation around the copper metal center and this attribution of switching is consistent with the observed temperature dependence of the switching behavior as well as the proposed energy diagram of the device. The observed resistance switching shows the potential for future non-volatile memories and logic devices applications. This review will discuss the progress and provide a perspective of molecular motion for nanoelectronics and other applications.

Blindness to a simultaneous change of all elements in a scene, unless there is a change in summary statistics.

PubMed

Saiki, Jun; Holcombe, Alex O

2012-03-06

Sudden change of every object in a display is typically conspicuous. We find however that in the presence of a secondary task, with a display of moving dots, it can be difficult to detect a sudden change in color of all the dots. A field of 200 dots, half red and half green, half moving rightward and half moving leftward, gave the appearance of two surfaces. When all 200 dots simultaneously switched color between red and green, performance in detecting the switch was very poor. A key display characteristic was that the color proportions on each surface (summary statistics) were not affected by the color switch. When the color switch is accompanied by a change in these summary statistics, people perform well in detecting the switch, suggesting that the secondary task does not disrupt the availability of this statistical information. These findings suggest that when the change is missed, the old and new colors were represented, but the color-location pattern (binding of colors to locations) was not represented or not compared. Even after extended viewing, changes to the individual color-location pattern are not available, suggesting that the feeling of seeing these details is misleading.

Switching single chain magnet behavior via photoinduced bidirectional metal-to-metal charge transfer† †Electronic supplementary information (ESI) available: Synthesis and physical measurement details. Crystal data in CIF format and additional figures (Fig. S1–S15). CCDC 1528877. For ESI and crystallographic data in CIF or other electronic format see DOI: 10.1039/c7sc03401f

PubMed Central

Jiang, Wenjing; Jiao, Chengqi; Meng, Yinshan; Zhao, Liang; Liu, Qiang

2017-01-01

The preparation of single-chain magnets (SCMs) with photo-switchable bistable states is essential for the development of high-density photo-recording devices. However, the reversible switching of the SCM behavior upon light irradiation is a formidable challenge. Here we report a well-isolated double zigzag chain {[Fe(bpy)(CN)4]2[Co(phpy)2]}·2H2O (bpy = 2,2′-bipyridine, phpy = 4-phenylpyridine), which exhibits reversible redox reactions with interconversion between FeIIILS(μ-CN)CoIIHS(μ-NC)FeIIILS (LS = low-spin, HS = high-spin) and FeIIILS(μ-CN)CoIIILS(μ-NC)FeIILS linkages under alternating irradiation with 808 and 532 nm lasers. The bidirectional photo-induced metal-to-metal charge transfer results in significant changes of anisotropy and intrachain magnetic interactions, reversibly switching the SCM behavior. The on-switching SCM behavior driven by light irradiation at 808 nm could be reversibly switched off by irradiation at 532 nm. The results provide an additional and independent way to control the bistable states of SCMs by switching in the 0 → 1 → 0 sequence, with potential applications in high density storage and molecular switches. PMID:29629126

Bilingual Language Switching in the Laboratory versus in the Wild: The Spatiotemporal Dynamics of Adaptive Language Control

PubMed Central

2017-01-01

For a bilingual human, every utterance requires a choice about which language to use. This choice is commonly regarded as part of general executive control, engaging prefrontal and anterior cingulate cortices similarly to many types of effortful task switching. However, although language control within artificial switching paradigms has been heavily studied, the neurobiology of natural switching within socially cued situations has not been characterized. Additionally, although theoretical models address how language control mechanisms adapt to the distinct demands of different interactional contexts, these predictions have not been empirically tested. We used MEG (RRID: NIFINV:nlx_inv_090918) to investigate language switching in multiple contexts ranging from completely artificial to the comprehension of a fully natural bilingual conversation recorded “in the wild.” Our results showed less anterior cingulate and prefrontal cortex involvement for more natural switching. In production, voluntary switching did not engage the prefrontal cortex or elicit behavioral switch costs. In comprehension, while laboratory switches recruited executive control areas, fully natural switching within a conversation only engaged auditory cortices. Multivariate pattern analyses revealed that, in production, interlocutor identity was represented in a sustained fashion throughout the different stages of language planning until speech onset. In comprehension, however, a biphasic pattern was observed: interlocutor identity was first represented at the presentation of the interlocutor and then again at the presentation of the auditory word. In all, our findings underscore the importance of ecologically valid experimental paradigms and offer the first neurophysiological characterization of language control in a range of situations simulating real life to various degrees. SIGNIFICANCE STATEMENT Bilingualism is an inherently social phenomenon, interactional context fully determining language choice. This research addresses the neural mechanisms underlying multilingual individuals' ability to successfully adapt to varying conversational contexts both while speaking and listening. Our results showed that interactional context critically determines language control networks' engagement: switching under external constraints heavily recruited prefrontal control regions, whereas natural, voluntary switching did not. These findings challenge conclusions derived from artificial switching paradigms, which suggested that language switching is intrinsically effortful. Further, our results predict that the so-called bilingual advantage should be limited to individuals who need to control their languages according to external cues and thus would not occur by virtue of an experience in which switching is fully free. PMID:28821648

Fully integrated graphene electronic biosensor for label-free detection of lead (II) ion based on G-quadruplex structure-switching.

PubMed

Li, Yijun; Wang, Cheng; Zhu, Yibo; Zhou, Xiaohong; Xiang, Yu; He, Miao; Zeng, Siyu

2017-03-15

This work presents a fully integrated graphene field-effect transistor (GFET) biosensor for the label-free detection of lead ions (Pb 2+ ) in aqueous-media, which first implements the G-quadruplex structure-switching biosensing principle in graphene nanoelectronics. We experimentally illustrate the biomolecular interplay that G-rich DNA single-strands with one-end confined on graphene surface can specifically interact with Pb 2+ ions and switch into G-quadruplex structures. Since the structure-switching of electrically charged DNA strands can disrupt the charge distribution in the vicinity of graphene surface, the carrier equilibrium in graphene sheet might be altered, and manifested by the conductivity variation of GFET. The experimental data and theoretical analysis show that our devices are capable of the label-free and specific quantification of Pb 2+ with a detection limit down to 163.7ng/L. These results first verify the signaling principle competency of G-quadruplex structure-switching in graphene electronic biosensors. Combining with the advantages of the compact device structure and convenient electrical signal, a label-free GFET biosensor for Pb 2+ monitoring is enabled with promising application potential. Copyright © 2016 Elsevier B.V. All rights reserved.

Flavin redox bifurcation as a mechanism for controlling the direction of electron flow during extracellular electron transfer.

PubMed

Okamoto, Akihiro; Hashimoto, Kazuhito; Nealson, Kenneth H

2014-10-06

The iron-reducing bacterium Shewanella oneidensis MR-1 has a dual directional electronic conduit involving 40 heme redox centers in flavin-binding outer-membrane c-type cytochromes (OM c-Cyts). While the mechanism for electron export from the OM c-Cyts to an anode is well understood, how the redox centers in OM c-Cyts take electrons from a cathode has not been elucidated at the molecular level. Electrochemical analysis of live cells during switching from anodic to cathodic conditions showed that altering the direction of electron flow does not require gene expression or protein synthesis, but simply redox potential shift about 300 mV for a flavin cofactor interacting with the OM c-Cyts. That is, the redox bifurcation of the riboflavin cofactor in OM c-Cyts switches the direction of electron conduction in the biological conduit at the cell-electrode interface to drive bacterial metabolism as either anode or cathode catalysts. © 2014 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

Method and apparatus for pulse width modulation control of an AC induction motor

DOEpatents

Geppert, Steven; Slicker, James M.

1984-01-01

An inverter is connected between a source of DC power and a three-phase AC induction motor, and a micro-processor-based circuit controls the inverter using pulse width modulation techniques. In the disclosed method of pulse width modulation, both edges of each pulse of a carrier pulse train are equally modulated by a time proportional to sin .THETA., where .THETA. is the angular displacement of the pulse center at the motor stator frequency from a fixed reference point on the carrier waveform. The carrier waveform frequency is a multiple of the motor stator frequency. The modulated pulse train is then applied to each of the motor phase inputs with respective phase shifts of 120.degree. at the stator frequency. Switching control commands of electronic switches in the inverter are stored in a random access memory (RAM) and the locations of the RAM are successively read out in a cyclic manner, each bit of a given RAM location controlling a respective phase input of the motor. The DC power source preferably comprises rechargeable batteries and all but one of the electronic switches in the inverter can be disabled, the remaining electronic switch being part of a "flyback" DC-DC converter circuit for recharging the battery.

Voltage Control of Metal-insulator Transition and Non-volatile Ferroelastic Switching of Resistance in VOx/PMN-PT Heterostructures

PubMed Central

Nan, Tianxiang; Liu, Ming; Ren, Wei; Ye, Zuo-Guang; Sun, Nian X.

2014-01-01

The central challenge in realizing electronics based on strongly correlated electronic states, or ‘Mottronics', lies in finding an energy efficient way to switch between the distinct collective phases with a control voltage in a reversible and reproducible manner. In this work, we demonstrate that a voltage-impulse-induced ferroelastic domain switching in the (011)-oriented 0.71Pb(Mg1/3Nb2/3)O3-0.29PbTiO3 (PMN-PT) substrates allows a robust non-volatile tuning of the metal-insulator transition in the VOx films deposited onto them. In such a VOx/PMN-PT heterostructure, the unique two-step electric polarization switching covers up to 90% of the entire poled area and contributes to a homogeneous in-plane anisotropic biaxial strain, which, in turn, enables the lattice changes and results in the suppression of metal-insulator transition in the mechanically coupled VOx films by 6 K with a resistance change up to 40% over a broad range of temperature. These findings provide a framework for realizing in situ and non-volatile tuning of strain-sensitive order parameters in strongly correlated materials, and demonstrate great potentials in delivering reconfigurable, compactable, and energy-efficient electronic devices. PMID:25088796

Voltage control of metal-insulator transition and non-volatile ferroelastic switching of resistance in VOx/PMN-PT heterostructures.

PubMed

Nan, Tianxiang; Liu, Ming; Ren, Wei; Ye, Zuo-Guang; Sun, Nian X

2014-08-04

The central challenge in realizing electronics based on strongly correlated electronic states, or 'Mottronics', lies in finding an energy efficient way to switch between the distinct collective phases with a control voltage in a reversible and reproducible manner. In this work, we demonstrate that a voltage-impulse-induced ferroelastic domain switching in the (011)-oriented 0.71Pb(Mg1/3Nb2/3)O3-0.29PbTiO3 (PMN-PT) substrates allows a robust non-volatile tuning of the metal-insulator transition in the VOx films deposited onto them. In such a VOx/PMN-PT heterostructure, the unique two-step electric polarization switching covers up to 90% of the entire poled area and contributes to a homogeneous in-plane anisotropic biaxial strain, which, in turn, enables the lattice changes and results in the suppression of metal-insulator transition in the mechanically coupled VOx films by 6 K with a resistance change up to 40% over a broad range of temperature. These findings provide a framework for realizing in situ and non-volatile tuning of strain-sensitive order parameters in strongly correlated materials, and demonstrate great potentials in delivering reconfigurable, compactable, and energy-efficient electronic devices.

Method and apparatus for pulse width modulation control of an AC induction motor

NASA Technical Reports Server (NTRS)

Geppert, Steven (Inventor); Slicker, James M. (Inventor)

1984-01-01

An inverter is connected between a source of DC power and a three-phase AC induction motor, and a micro-processor-based circuit controls the inverter using pulse width modulation techniques. In the disclosed method of pulse width modulation, both edges of each pulse of a carrier pulse train are equally modulated by a time proportional to sin .THETA., where .THETA. is the angular displacement of the pulse center at the motor stator frequency from a fixed reference point on the carrier waveform. The carrier waveform frequency is a multiple of the motor stator frequency. The modulated pulse train is then applied to each of the motor phase inputs with respective phase shifts of 120.degree. at the stator frequency. Switching control commands of electronic switches in the inverter are stored in a random access memory (RAM) and the locations of the RAM are successively read out in a cyclic manner, each bit of a given RAM location controlling a respective phase input of the motor. The DC power source preferably comprises rechargeable batteries and all but one of the electronic switches in the inverter can be disabled, the remaining electronic switch being part of a flyback DC-DC converter circuit for recharging the battery.

Bistable metamaterial for switching and cascading elastic vibrations

PubMed Central

Foehr, André; Daraio, Chiara

2017-01-01

The realization of acoustic devices analogous to electronic systems, like diodes, transistors, and logic elements, suggests the potential use of elastic vibrations (i.e., phonons) in information processing, for example, in advanced computational systems, smart actuators, and programmable materials. Previous experimental realizations of acoustic diodes and mechanical switches have used nonlinearities to break transmission symmetry. However, existing solutions require operation at different frequencies or involve signal conversion in the electronic or optical domains. Here, we show an experimental realization of a phononic transistor-like device using geometric nonlinearities to switch and amplify elastic vibrations, via magnetic coupling, operating at a single frequency. By cascading this device in a tunable mechanical circuit board, we realize the complete set of mechanical logic elements and interconnect selected ones to execute simple calculations. PMID:28416663

Electron-Beam Switches For A High Peak Power Sled-II Pulse Compressor

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

Hirshfield, Jay, L.

2015-12-02

Omega-P demonstrated triggered electron-beam switches on the L=2 m dual-delay-line X-band pulse compressor at Naval Research Laboratory (NRL). In those experiments, with input pulses of up to 9 MW from the Omega-P/NRL X-band magnicon, output pulses having peak powers of 140-165 MW and durations of 16-20 ns were produced, with record peak power gains M of 18-20. Switch designs are described based on the successful results that should be suitable for use with the existing SLAC SLED-II delay line system, to demonstrate C=9, M=7, and n>>78%, yielding 173ns compressed pulses with peak powers up to 350MW with input of amore » single 50-MW.« less

Realization of a four-step molecular switch in scanning tunneling microscope manipulation of single chlorophyll-a molecules

PubMed Central

Iancu, Violeta; Hla, Saw-Wai

2006-01-01

Single chlorophyll-a molecules, a vital resource for the sustenance of life on Earth, have been investigated by using scanning tunneling microscope manipulation and spectroscopy on a gold substrate at 4.6 K. Chlorophyll-a binds on Au(111) via its porphyrin unit while the phytyl-chain is elevated from the surface by the support of four CH3 groups. By injecting tunneling electrons from the scanning tunneling microscope tip, we are able to bend the phytyl-chain, which enables the switching of four molecular conformations in a controlled manner. Statistical analyses and structural calculations reveal that all reversible switching mechanisms are initiated by a single tunneling-electron energy-transfer process, which induces bond rotation within the phytyl-chain. PMID:16954201

Diffused Silicon Transistors and Switches (1954-55): The Beginning of Integrated Circuit Technology

NASA Astrophysics Data System (ADS)

Holonyak, N.

2003-09-01

Silicon (Si) transistor and integrated circuit (IC) technology has grown so big, and become so important, that it is now hard to recognize where, apart from the invention of the transistor itself (Bardeen and Brattain, Dec 16, 1947), it had its origin. In spite of obvious differences in Ge and Si, in 1950-55 it was not evident in many laboratories, concentrating only on Ge, what form of Ge transistor (grown, alloyed, jet-etched, etc.) might be expected to prevail, with Si not even being considered (or being dismissed outright). What was the need for Si and, at the time, such a seemingly intractable peculiar new technology? The requirement on switching devices of low leakage, and thus the need to leave Ge in favor of Si, led directly in 1954-55 (Bell Telephone Laboratories, BTL) to the exploration of impurity-diffusion and metallization technology to realize Si transistors and p-n-p-n switches. This technology, a more or less ideal thin-layer technology that can be referenced from a single surface (and which indeed has proven to be basically invariant and constantly growing), led further to the discovery (1955) of the protective Si oxide, oxide masking and patterning, and the fundamental basis of the integrated circuit (i.e., device-to-device interconnection by patterned metallization across the oxide). We recount some of the exploratory diffused-impurity Si device development of 1954-55 at BTL, particularly the work in and near Moll's group, that helped to establish the basis for today's electronics. The Si diffused-impurity devices of 1954-55 are described, including work and data not previously reported or broadly known—in fact, much work and data (a new technology) that was carried across the Country to a place that became known as Silicon Valley. For further perspective, an appendix is included of independent early suggestions of Bardeen (Urbana notebook, Feb 1952) to leave Ge in favor of diffused Si devices.

The effect of working gas pressure on the switching rate of a kivotron

NASA Astrophysics Data System (ADS)

Bokhan, P. A.; Gugin, P. P.; Zakrevsky, D. E.; Lavrukhin, M. A.

2016-05-01

The switching rate in gas-discharge devices (kivotrons) based on an "open" discharge with counterpropagating electron beams is studied experimentally. Structures with a total cathode area of 2 cm2 were used. A monotonic reduction in the switching time with an increase in the working gas pressure and in the voltage amplitude at the time of breakdown is demonstrated. The minimum switching time is ~240 ps at a voltage of 17 kV. The maximum current rise rate, which is limited by the discharge circuit inductance, is 3 × 1012 A/s.

Low Temperature Resistive Switching Behavior in a Manganite

NASA Astrophysics Data System (ADS)

Salvo, Christopher; Lopez, Melinda; Tsui, Stephen

2012-02-01

The development of new nonvolatile memory devices remains an important field of consumer electronics. A possible candidate is bipolar resistive switching, a method by which the resistance of a material changes when a voltage is applied. Although there is a great deal of research on this topic, not much has been done at low temperatures. In this work, we compare the room temperature and low temperature behaviors of switching in a manganite thin film. The data indicates that the switching is suppressed upon cooling to cryogenic temperatures, and the presence of crystalline charge traps is tied to the physical mechanism.

Printed Antennas Made Reconfigurable by Use of MEMS Switches

NASA Technical Reports Server (NTRS)

Simons, Rainee N.

2005-01-01

A class of reconfigurable microwave antennas now undergoing development comprise fairly conventional printed-circuit feed elements and radiating patches integrated with novel switches containing actuators of the microelectromechanical systems (MEMS) type. In comparison with solid-state electronic control devices incorporated into some prior printed microwave antennas, the MEMS-based switches in these antennas impose lower insertion losses and consume less power. Because the radio-frequency responses of the MEMS switches are more nearly linear, they introduce less signal distortion. In addition, construction and operation are simplified because only a single DC bias line is needed to control each MEMS actuator.

From dead leaves to sustainable organic resistive switching memory.

PubMed

Sun, Bai; Zhu, Shouhui; Mao, Shuangsuo; Zheng, Pingping; Xia, Yudong; Yang, Feng; Lei, Ming; Zhao, Yong

2018-03-01

An environmental-friendly, sustainable, pollution-free, biodegradable, flexible and wearable electronic device hold advanced potential applications. Here, an organic resistive switching memory device with Ag/Leaves/Ti/PET structure on a flexible polyethylene terephthalate (PET) substrate was fabricated for the first time. We observed an obvious resistive switching memory characteristic with large switching resistance ratio and stable cycle performance at room temperature. This work demonstrates that leaves, a useless waste, can be properly treated to make useful devices. Furthermore, the as-fabricated devices can be degraded naturally without damage to the environment. Copyright © 2017 Elsevier Inc. All rights reserved.

Metal vapor arc switch electromagnetic accelerator technology

NASA Technical Reports Server (NTRS)

Mongeau, P. P.

1984-01-01

A multielectrode device housed in an insulator vacuum vessel, the metal vapor vacuum switch has high power capability and can hold off voltages up to the 100 kilovolt level. Such switches can be electronically triggered and can interrupt or commutate at a zero current crossing. The physics of arc initiation, arc conduction, and interruption are examined, including material considerations; inefficiencies; arc modes; magnetic field effects; passive and forced extinction; and voltage recovery. Heating, electrode lifetime, device configuration, and external circuit configuration are discussed. The metal vapor vacuum switch is compared with SCRs, GTOs, spark gaps, ignitrons, and mechanical breakers.

CMOS-Compatible SOI MESFETS for Radiation-Hardened DC-to-DC Converters

NASA Technical Reports Server (NTRS)

Thornton, Trevor; Lepkowski, William; Wilk, Seth

2013-01-01

A radiation-tolerant transistor switch has been developed that can operate between 196 and +150 C for DC-to-DC power conversion applications. A prototype buck regulator component was demonstrated to be performing well after a total ionizing dose of 300 krad(Si). The prototype buck converters showed good efficiencies at ultra-high switching speeds in the range of 1 to 10 MHz. Such high switching frequency will enable smaller, lighter buck converters to be developed as part of the next project. Switching regulators are widely used in commercial applications including portable consumer electronics.

Membrane-bound MinDE complex acts as a toggle switch that drives Min oscillation coupled to cytoplasmic depletion of MinD.

PubMed

Vecchiarelli, Anthony G; Li, Min; Mizuuchi, Michiyo; Hwang, Ling Chin; Seol, Yeonee; Neuman, Keir C; Mizuuchi, Kiyoshi

2016-03-15

The Escherichia coli Min system self-organizes into a cell-pole to cell-pole oscillator on the membrane to prevent divisions at the cell poles. Reconstituting the Min system on a lipid bilayer has contributed to elucidating the oscillatory mechanism. However, previous in vitro patterns were attained with protein densities on the bilayer far in excess of those in vivo and failed to recapitulate the standing wave oscillations observed in vivo. Here we studied Min protein patterning at limiting MinD concentrations reflecting the in vivo conditions. We identified "burst" patterns--radially expanding and imploding binding zones of MinD, accompanied by a peripheral ring of MinE. Bursts share several features with the in vivo dynamics of the Min system including standing wave oscillations. Our data support a patterning mechanism whereby the MinD-to-MinE ratio on the membrane acts as a toggle switch: recruiting and stabilizing MinD on the membrane when the ratio is high and releasing MinD from the membrane when the ratio is low. Coupling this toggle switch behavior with MinD depletion from the cytoplasm drives a self-organized standing wave oscillator.

Ferroelastic domain switching dynamics under electrical and mechanical excitations.

PubMed

Gao, Peng; Britson, Jason; Nelson, Christopher T; Jokisaari, Jacob R; Duan, Chen; Trassin, Morgan; Baek, Seung-Hyub; Guo, Hua; Li, Linze; Wang, Yiran; Chu, Ying-Hao; Minor, Andrew M; Eom, Chang-Beom; Ramesh, Ramamoorthy; Chen, Long-Qing; Pan, Xiaoqing

2014-05-02

In thin film ferroelectric devices, switching of ferroelastic domains can significantly enhance electromechanical response. Previous studies have shown disagreement regarding the mobility or immobility of ferroelastic domain walls, indicating that switching behaviour strongly depends on specific microstructures in ferroelectric systems. Here we study the switching dynamics of individual ferroelastic domains in thin Pb(Zr0.2,Ti0.8)O3 films under electrical and mechanical excitations by using in situ transmission electron microscopy and phase-field modelling. We find that ferroelastic domains can be effectively and permanently stabilized by dislocations at the substrate interface while similar domains at free surfaces without pinning dislocations can be removed by either electric or stress fields. For both electrical and mechanical switching, ferroelastic switching is found to occur most readily at the highly active needle points in ferroelastic domains. Our results provide new insights into the understanding of polarization switching dynamics as well as the engineering of ferroelectric devices.

Ferroelastic domain switching dynamics under electrical and mechanical excitations

NASA Astrophysics Data System (ADS)

Gao, Peng; Britson, Jason; Nelson, Christopher T.; Jokisaari, Jacob R.; Duan, Chen; Trassin, Morgan; Baek, Seung-Hyub; Guo, Hua; Li, Linze; Wang, Yiran; Chu, Ying-Hao; Minor, Andrew M.; Eom, Chang-Beom; Ramesh, Ramamoorthy; Chen, Long-Qing; Pan, Xiaoqing

2014-05-01

In thin film ferroelectric devices, switching of ferroelastic domains can significantly enhance electromechanical response. Previous studies have shown disagreement regarding the mobility or immobility of ferroelastic domain walls, indicating that switching behaviour strongly depends on specific microstructures in ferroelectric systems. Here we study the switching dynamics of individual ferroelastic domains in thin Pb(Zr0.2,Ti0.8)O3 films under electrical and mechanical excitations by using in situ transmission electron microscopy and phase-field modelling. We find that ferroelastic domains can be effectively and permanently stabilized by dislocations at the substrate interface while similar domains at free surfaces without pinning dislocations can be removed by either electric or stress fields. For both electrical and mechanical switching, ferroelastic switching is found to occur most readily at the highly active needle points in ferroelastic domains. Our results provide new insights into the understanding of polarization switching dynamics as well as the engineering of ferroelectric devices.

Improvement on Main/backup Controller Switching Device of the Nozzle Throat Area Control System for a Turbofan Aero Engine

NASA Astrophysics Data System (ADS)

Li, Jie; Duan, Minghu; Yan, Maode; Li, Gang; Li, Xiaohui

2014-06-01

A full authority digital electronic controller (FADEC) equipped with a full authority hydro-mechanical backup controller (FAHMBC) is adopted as the nozzle throat area control system (NTACS) of a turbofan aero engine. In order to ensure the switching reliability of the main/backup controller, the nozzle throat area control switching valve was improved from three-way convex desktop slide valve to six-way convex desktop slide valve. Simulation results show that, if malfunctions of FAEDC occur and abnormal signals are outputted from FADEC, NTACS will be seriously influenced by the main/backup controller switching in several working states, while NTACS will not be influenced by using the improved nozzle throat area control switching valve, thus the controller switching process will become safer and smoother and the working reliability of this turbofan aero engine is improved by the controller switching device improvement.

The 10 kW power electronics for hydrogen arcjets

NASA Technical Reports Server (NTRS)

Hamley, John A.; Pinero, Luis R.; Hill, Gerald M.

1992-01-01

A combination of emerging mission considerations such as 'launch on schedule', resource limitations, and the development of higher power spacecraft busses has resulted in renewed interest in high power hydrogen arcjet systems with specific impulses greater than 1000 s for Earth-space orbit transfer and maneuver applications. Solar electric propulsion systems with about 10 kW of power appear to offer payload benefits at acceptable trip times. This work outlines the design and development of 10 kW hydrogen arcjet power electronics and results of arcjet integration testing. The power electronics incorporated a full bridge switching topology similar to that employed in state of the art 5 kW power electronics, and the output filter included an output current averaging inductor with an integral pulse generation winding for arcjet ignition. Phase shifted, pulse width modulation with current mode control was used to regulate the current delivered to arcjet, and a low inductance power stage minimized switching transients. Hybrid power Metal Oxide Semiconductor Field Effect Transistors were used to minimize conduction losses. Switching losses were minimized using a fast response, optically isolated, totem-pole gate drive circuit. The input bus voltage for the unit was 150 V, with a maximum output voltage of 225 V. The switching frequency of 20 kHz was a compromise between mass savings and higher efficiency. Power conversion efficiencies in excess of 0.94 were demonstrated, along with steady state load current regulation of 1 percent. The power electronics were successfully integrated with a 10 kW laboratory hydrogen arcjet, and reliable, nondestructive starts and transitions to steady state operation were demonstrated. The estimated specific mass for a flight packaged unit was 2 kg/kW.

Changes in puffing behavior among smokers who switched from tobacco to electronic cigarettes

PubMed Central

Lee, Yong Hee; Gawron, Michal; Goniewicz, Maciej Lukasz

2015-01-01

Introduction Nicotine intake from electronic cigarette (e-cigarettes) increases with user’s experience. This suggests that smokers who switched from tobacco to electronic cigarettes compensate for nicotine over the time to get as much nicotine as they need. One of the mechanism by which smokers may compensate for nicotine is by modifying their puffing behavior. The aim of the study was to assess the changes in puffing behavior after switching from conventional to electronic cigarettes among regular smokers. Materials and Methods Twenty smokers (11 female, aged 31±10, CPD 16±8, FTND 4±3, and exhaled CO 16±17 (mean±SD)) who were naïve to e-cigarettes participated in this study. They were asked to substitute their regular tobacco cigarettes with first generation e-cigarettes (labelled 18 mg nicotine) for two weeks. Puffing topography (number of puffs, puff volume, intervals between puffs, and average puff flow rate) was measured at the initial use (baseline), as well as after one and two weeks of product use. We tested changes in puffing topography outcomes using repeated measures ANOVA. Results We found that after one week of using e-cigarettes, participants significantly increased the average time they puffed on e-cigarettes from 2.2±0.1 (mean±SEM) to 3.1±0.3 sec (p<0.05). The average puff flow rate decreased from 30.6±2.3 to 25.1±1.8 ml/sec after one week of e-cigarette use (p<0.05). Conclusions Our data show that smokers modify their puffing behavior after switching from tobacco to electronic cigarettes by taking longer and slower puffs. The potential reason for changing puffing behavior is to compensate for less efficient nicotine delivery from e-cigarettes. PMID:25930009

Changes in puffing behavior among smokers who switched from tobacco to electronic cigarettes.

PubMed

Lee, Yong Hee; Gawron, Michal; Goniewicz, Maciej Lukasz

2015-09-01

Nicotine intake from electronic cigarette (e-cigarettes) increases with user's experience. This suggests that smokers who switched from tobacco to electronic cigarettes compensate for nicotine over time to get as much nicotine as they need. One of the mechanisms by which smokers may compensate for nicotine is by modifying their puffing behavior. The aim of the study was to assess the changes in puffing behavior after switching from conventional to electronic cigarettes among regular smokers. Twenty smokers (11 female, aged 31±10, CPD 16±8, FTND 4±3, and exhaled CO 16±17 (mean±SD)) who were naïve to e-cigarettes participated in this study. They were asked to substitute their regular tobacco cigarettes with first generation e-cigarettes (labeled 18mg nicotine) for two weeks. Puffing topography (number of puffs, puff volume, intervals between puffs, and average puff flow rate) was measured at the initial use (baseline), as well as after one and two weeks of product use. We tested changes in puffing topography outcomes using repeated measures ANOVA. We found that after one week of using e-cigarettes, participants significantly increased the average time they puffed on e-cigarettes from 2.2±0.1 (mean±SEM) to 3.1±0.3s (p<0.05). The average puff flow rate decreased from 30.6±2.3 to 25.1±1.8ml/s after one week of e-cigarette use (p<0.05). Our data show that smokers modify their puffing behavior after switching from tobacco to electronic cigarettes by taking longer and slower puffs. The potential reason for changing puffing behavior is to compensate for less efficient nicotine delivery from e-cigarettes. Copyright © 2015 Elsevier Ltd. All rights reserved.

Charge Catastrophe and Dielectric Breakdown During Exposure of Organic Thin Films to Low-Energy Electron Radiation

NASA Astrophysics Data System (ADS)

Thete, A.; Geelen, D.; van der Molen, S. J.; Tromp, R. M.

2017-12-01

The effects of exposure to ionizing radiation are central in many areas of science and technology, including medicine and biology. Absorption of UV and soft-x-ray photons releases photoelectrons, followed by a cascade of lower energy secondary electrons with energies down to 0 eV. While these low energy electrons give rise to most chemical and physical changes, their interactions with soft materials are not well studied or understood. Here, we use a low energy electron microscope to expose thin organic resist films to electrons in the range 0-50 eV, and to analyze the energy distribution of electrons returned to the vacuum. We observe surface charging that depends strongly and nonlinearly on electron energy and electron beam current, abruptly switching sign during exposure. Charging can even be sufficiently severe to induce dielectric breakdown across the film. We provide a simple but comprehensive theoretical description of these phenomena, identifying the presence of a cusp catastrophe to explain the sudden switching phenomena seen in the experiments. Surprisingly, the films undergo changes at all incident electron energies, starting at ˜0 eV .

Nanoscale control of an interfacial metal-insulator transition at room temperature.

PubMed

Cen, C; Thiel, S; Hammerl, G; Schneider, C W; Andersen, K E; Hellberg, C S; Mannhart, J; Levy, J

2008-04-01

Experimental and theoretical investigations have demonstrated that a quasi-two-dimensional electron gas (q-2DEG) can form at the interface between two insulators: non-polar SrTiO3 and polar LaTiO3 (ref. 2), LaAlO3 (refs 3-5), KTaO3 (ref. 7) or LaVO3 (ref. 6). Electronically, the situation is analogous to the q-2DEGs formed in semiconductor heterostructures by modulation doping. LaAlO3/SrTiO3 heterostructures have recently been shown to exhibit a hysteretic electric-field-induced metal-insulator quantum phase transition for LaAlO3 thicknesses of 3 unit cells. Here, we report the creation and erasure of nanoscale conducting regions at the interface between two insulating oxides, LaAlO3 and SrTiO3. Using voltages applied by a conducting atomic force microscope (AFM) probe, the buried LaAlO3/SrTiO3 interface is locally and reversibly switched between insulating and conducting states. Persistent field effects are observed using the AFM probe as a gate. Patterning of conducting lines with widths of approximately 3 nm, as well as arrays of conducting islands with densities >10(14) inch(-2), is demonstrated. The patterned structures are stable for >24 h at room temperature.

Experimental investigation on the development characteristics of initial electrons in a gas pressurized closing switch under DC voltage

NASA Astrophysics Data System (ADS)

Rongxiao, ZHAI; Mengtong, QIU; Weixi, LUO; Peitian, CONG; Tao, HUANG; Jiahui, YIN; Tianyang, ZHANG

2018-04-01

As one of the most important elements in linear transformer driver (LTD) based systems, the gas pressurized closing switches are required to operate with a very low prefire probability during the DC-charging process to ensure reliable operation and stable output of the whole pulsed power system. The most direct and effective way to control the prefire probability is to select a suitable working coefficient. The study of the development characteristics of the initially generated electrons is useful for optimizing the working coefficient and improving the prefire characteristic of the switches. In this paper an ultraviolet pulsed laser is used to generate initial electrons inside the gap volume. A current measuring system is used to measure the time-dependent current generated by the growth of the initial electrons so as to study the development characteristics of the electrons under different working coefficients. Experimental results show that the development characteristics of the initial electrons are influenced obviously by the working coefficient. With the increase of the working coefficient, the development degree of the electrons increases consequently. At the same times, there is a threshold of working coefficient which produces the effect of ionization on electrons. The range of the threshold has a slow growth but remains close to 65% with the gas pressure increase. When the working coefficient increases further, γ processes are starting to be generated inside the gap volume. In addition, an optimal working coefficient beneficial for improving the prefire characteristic is indicated and further tested.

Hilbert-Curve Fractal Antenna With Radiation- Pattern Diversity

NASA Technical Reports Server (NTRS)

Nessel, James A.; Miranda, Felix A.; Zaman, Afroz

2007-01-01

A printed, folded, Hilbert-curve fractal microwave antenna has been designed and built to offer advantages of compactness and low mass, relative to other antennas designed for the same operating frequencies. The primary feature of the antenna is that it offers the advantage of radiation-pattern diversity without need for electrical or mechanical switching: it can radiate simultaneously in an end-fire pattern at a frequency of 2.3 GHz (which is in the S-band) and in a broadside pattern at a frequency of 16.8 GHz (which is in the Ku-band). This radiation-pattern diversity could be utilized, for example, in applications in which there were requirements for both S-band ground-to-ground communications and Ku-band ground-to-aircraft or ground-to-spacecraft communications. The lack of switching mechanisms or circuitry makes this antenna more reliable, easier, and less expensive to fabricate than it otherwise would be.

Multiple independent autonomous hydraulic oscillators driven by a common gravity head.

PubMed

Kim, Sung-Jin; Yokokawa, Ryuji; Lesher-Perez, Sasha Cai; Takayama, Shuichi

2015-06-15

Self-switching microfluidic circuits that are able to perform biochemical experiments in a parallel and autonomous manner, similar to instruction-embedded electronics, are rarely implemented. Here, we present design principles and demonstrations for gravity-driven, integrated, microfluidic pulsatile flow circuits. With a common gravity head as the only driving force, these fluidic oscillator arrays realize a wide range of periods (0.4 s-2 h) and flow rates (0.10-63 μl min(-1)) with completely independent timing between the multiple oscillator sub-circuits connected in parallel. As a model application, we perform systematic, parallel analysis of endothelial cell elongation response to different fluidic shearing patterns generated by the autonomous microfluidic pulsed flow generation system.

High-resolution inkjet printing of all-polymer transistor circuits.

PubMed

Sirringhaus, H; Kawase, T; Friend, R H; Shimoda, T; Inbasekaran, M; Wu, W; Woo, E P

2000-12-15

Direct printing of functional electronic materials may provide a new route to low-cost fabrication of integrated circuits. However, to be useful it must allow continuous manufacturing of all circuit components by successive solution deposition and printing steps in the same environment. We demonstrate direct inkjet printing of complete transistor circuits, including via-hole interconnections based on solution-processed polymer conductors, insulators, and self-organizing semiconductors. We show that the use of substrate surface energy patterning to direct the flow of water-based conducting polymer inkjet droplets enables high-resolution definition of practical channel lengths of 5 micrometers. High mobilities of 0.02 square centimeters per volt second and on-off current switching ratios of 10(5) were achieved.

Electric field-triggered metal-insulator transition resistive switching of bilayered multiphasic VOx

NASA Astrophysics Data System (ADS)

Won, Seokjae; Lee, Sang Yeon; Hwang, Jungyeon; Park, Jucheol; Seo, Hyungtak

2018-01-01

Electric field-triggered Mott transition of VO2 for next-generation memory devices with sharp and fast resistance-switching response is considered to be ideal but the formation of single-phase VO2 by common deposition techniques is very challenging. Here, VOx films with a VO2-dominant phase for a Mott transition-based metal-insulator transition (MIT) switching device were successfully fabricated by the combined process of RF magnetron sputtering of V metal and subsequent O2 annealing to form. By performing various material characterizations, including scanning transmission electron microscopy-electron energy loss spectroscopy, the film is determined to have a bilayer structure consisting of a VO2-rich bottom layer acting as the Mott transition switching layer and a V2O5/V2O3 mixed top layer acting as a control layer that suppresses any stray leakage current and improves cyclic performance. This bilayer structure enables excellent electric field-triggered Mott transition-based resistive switching of Pt-VOx-Pt metal-insulator-metal devices with a set/reset current ratio reaching 200, set/reset voltage of less than 2.5 V, and very stable DC cyclic switching upto 120 cycles with a great set/reset current and voltage distribution less than 5% of standard deviation at room temperature, which are specifications applicable for neuromorphic or memory device applications. [Figure not available: see fulltext.

Fabrication and Electrical Characterization of Correlated Oxide Field Effect Switching Devices for High Speed Electronics

DTIC Science & Technology

2015-11-19

Shriram Ramanathan HARVARD COLLEGE PRESIDENT & FELLOWS OF Final Report 11/19/2015 DISTRIBUTION A: Distribution approved for public release. AF Office... Harvard University 29 Oxford St, Pierce Hall, Cambridge, MA 02138 8. PERFORMING ORGANIZATION REPORT NUMBER 9. SPONSORING/MONITORING AGENCY NAME(S...characterization of correlated oxide field effect switching devices for  high speed electronics  PI: Shriram Ramanathan,  Harvard  University  AFOSR Grant FA9550‐12‐1

Multistage switching hardware and software implementations for student experiment purpose

NASA Astrophysics Data System (ADS)

Sani, A.; Suherman

2018-02-01

Current communication and internet networks are underpinned by the switching technologies that interconnect one network to the others. Students’ understanding on networks rely on how they conver the theories. However, understanding theories without touching the reality may exert spots in the overall knowledge. This paper reports the progress of the multistage switching design and implementation for student laboratory activities. The hardware and software designs are based on three stages clos switching architecture with modular 2x2 switches, controlled by an arduino microcontroller. The designed modules can also be extended for batcher and bayan switch, and working on circuit and packet switching systems. The circuit analysis and simulation show that the blocking probability for each switch combinations can be obtained by generating random or patterned traffics. The mathematic model and simulation analysis shows 16.4% blocking probability differences as the traffic generation is uniform. The circuits design components and interfacing solution have been identified to allow next step implementation.

RRAM-based parallel computing architecture using k-nearest neighbor classification for pattern recognition

NASA Astrophysics Data System (ADS)

Jiang, Yuning; Kang, Jinfeng; Wang, Xinan

2017-03-01

Resistive switching memory (RRAM) is considered as one of the most promising devices for parallel computing solutions that may overcome the von Neumann bottleneck of today’s electronic systems. However, the existing RRAM-based parallel computing architectures suffer from practical problems such as device variations and extra computing circuits. In this work, we propose a novel parallel computing architecture for pattern recognition by implementing k-nearest neighbor classification on metal-oxide RRAM crossbar arrays. Metal-oxide RRAM with gradual RESET behaviors is chosen as both the storage and computing components. The proposed architecture is tested by the MNIST database. High speed (~100 ns per example) and high recognition accuracy (97.05%) are obtained. The influence of several non-ideal device properties is also discussed, and it turns out that the proposed architecture shows great tolerance to device variations. This work paves a new way to achieve RRAM-based parallel computing hardware systems with high performance.

Spin interferometry in anisotropic spin-orbit fields

NASA Astrophysics Data System (ADS)

Saarikoski, Henri; Reynoso, Andres A.; Baltanás, José Pablo; Frustaglia, Diego; Nitta, Junsaku

2018-03-01

Electron spins in a two-dimensional electron gas can be manipulated by spin-orbit (SO) fields originating from either Rashba or Dresselhaus interactions with independent isotropic characteristics. Together, though, they produce anisotropic SO fields with consequences on quantum transport through spin interference. Here we study the transport properties of modeled mesoscopic rings subject to Rashba and Dresselhaus [001] SO couplings in the presence of an additional in-plane Zeeman field acting as a probe. By means of one- and two-dimensional quantum transport simulations we show that this setting presents anisotropies in the quantum resistance as a function of the Zeeman field direction. Moreover, the anisotropic resistance can be tuned by the Rashba strength up to the point to invert its response to the Zeeman field. We also find that a topological transition in the field texture that is associated with a geometric phase switching is imprinted in the anisotropy pattern. We conclude that resistance anisotropy measurements can reveal signatures of SO textures and geometric phases in spin carriers.

Non-switching to switching transferring mechanism investigation for Ag/SiO x /p-Si structure with SiO x deposited by HWCVD

NASA Astrophysics Data System (ADS)

Liu, Yanhong; Wang, Ruoying; Li, Zhongyue; Wang, Song; Huang, Yang; Peng, Wei

2018-04-01

We proposed and fabricated an Ag/SiO x /p-Si sandwich structure, in which amorphous SiO x films were deposited through hot wire chemical vapor deposition (HWCVD) using tetraethylorthosilicate (TEOS) as Si and O precursor. Experimental results indicate that the I–V properties of this structure transfer from non-switching to switching operation as the SiO x deposition temperature increased. The device with SiO x deposited at high deposition temperature exhibits typical bipolar switching properties, which can be potentially used in resistive switching random accessible memory (RRAM). The transferring mechanism from non-switching to switching can be ascribed to the change of structural and electronic properties of SiO x active layer deposited at different temperatures, as evidenced by analyzing FTIR spectrum and fitting its I–V characteristics curves. This work demonstrates a safe and practicable low-temperature device-grade SiO x film deposition technology by conducting HWCVD from TEOS.

Non-volatile, solid state bistable electrical switch

NASA Technical Reports Server (NTRS)

Williams, Roger M. (Inventor)

1994-01-01

A bistable switching element is made of a material whose electrical resistance reversibly decreases in response to intercalation by positive ions. Flow of positive ions between the bistable switching element and a positive ion source is controlled by means of an electrical potential applied across a thermal switching element. The material of the thermal switching element generates heat in response to electrical current flow therethrough, which in turn causes the material to undergo a thermal phase transition from a high electrical resistance state to a low electrical resistance state as the temperature increases above a predetermined value. Application of the electrical potential in one direction renders the thermal switching element conductive to pass electron current out of the ion source. This causes positive ions to flow from the source into the bistable switching element and intercalate the same to produce a non-volatile, low resistance logic state. Application of the electrical potential in the opposite direction causes reverse current flow which de-intercalates the bistable logic switching element and produces a high resistance logic state.

Exceptional-point Dynamics in Photonic Honeycomb Lattices with PT Symmetry

DTIC Science & Technology

2012-01-17

coherent perfect laser absorber [25], spatial optical switches [26], and nonlinear switching structures [27]. Despite the wealth of results on...Petermann, IEEE J. Quantum Electron. 15, 566 (1979); A. E. Siegman , Phys. Rev. A 39, 1264 (1989). [36] M. V. Berry, J. Mod. Opt. 50, 63 (2003); S.-Y

High-Voltage MOSFET Switching Circuit

NASA Technical Reports Server (NTRS)

Jensen, Kenneth A.

1995-01-01

Circuit reliably switches power at supply potential of minus 1,500 V, with controlled frequency and duty cycle. Used in argon-plasma ion-bombardment equipment for texturing copper electrodes, as described in "Texturing Copper To Reduce Secondary Emission of Electrons" (LEW-15898), also adapted to use in powering gaseous flash lamps and stroboscopes.

Comparative population genetics of a mimicry locus among hybridizing Heliconius butterfly species.

PubMed

Chamberlain, N L; Hill, R I; Baxter, S W; Jiggins, C D; Kronforst, M R

2011-09-01

The comimetic Heliconius butterfly species pair, H. erato and H. melpomene, appear to use a conserved Mendelian switch locus to generate their matching red wing patterns. Here we investigate whether H. cydno and H. pachinus, species closely related to H. melpomene, use this same switch locus to generate their highly divergent red and brown color pattern elements. Using an F2 intercross between H. cydno and H. pachinus, we first map the genomic positions of two novel red/brown wing pattern elements; the G locus, which controls the presence of red vs brown at the base of the ventral wings, and the Br locus, which controls the presence vs absence of a brown oval pattern on the ventral hind wing. The results reveal that the G locus is tightly linked to markers in the genomic interval that controls red wing pattern elements of H. erato and H. melpomene. Br is on the same linkage group but approximately 26 cM away. Next, we analyze fine-scale patterns of genetic differentiation and linkage disequilibrium throughout the G locus candidate interval in H. cydno, H. pachinus and H. melpomene, and find evidence for elevated differentiation between H. cydno and H. pachinus, but no localized signature of association. Overall, these results indicate that the G locus maps to the same interval as the locus controlling red patterning in H. melpomene and H. erato. This, in turn, suggests that the genes controlling red pattern elements may be homologous across Heliconius, supporting the hypothesis that Heliconius butterflies use a limited suite of conserved genetic switch loci to generate both convergent and divergent wing patterns.

Treatment patterns in disease-modifying therapy for patients with multiple sclerosis in the United States.

PubMed

Bonafede, Machaon M; Johnson, Barbara H; Wenten, Madé; Watson, Crystal

2013-10-01

Patients with multiple sclerosis (MS) whose disease activity is inadequately controlled with a platform therapy (interferon beta or glatiramer acetate [GA]) may switch to another platform therapy or escalate therapy to natalizumab or fingolimod, which were approved in the US in 2006 and 2010, respectively. The objective of this study was to describe treatment patterns in patients with multiple sclerosis (MS) in the United States who were followed for 2 years after initiating a disease-modifying therapy (DMT). A retrospective observational cohort study was conducted to examine treatment patterns of initial DMT use (on initial therapy for 2 years with and without gaps of ≥ 60 days, medication switching, and discontinuation) among patients with MS who initiated a platform therapy (interferon-β or glatiramer acetate) or natalizumab between January 1, 2007, and September 30, 2009; the first DMT claim was the index. Eligible patients were identified in the MarketScan Commercial and Medicare Supplemental databases based on continuous enrollment for 6 months before (preindex period) and 24 months after their index date, with a diagnosis of MS and no claim for a previous DMT in the 6-month preindex period. Demographics at index and clinical characteristics during the preindex period were also analyzed. A total of 6181 MS patients were included, with 5735 (92.8%) starting on platform therapy. Natalizumab initiators were more likely to stay on index therapy (32.3% vs 16.9%, P < 0.001) and have fewer treatment gaps of ≥ 60 days (44.8% vs 55.3%, P < 0.001) compared with platform initiators. In addition, natalizumab initiators were less likely to switch treatment (13.9% vs 19.1%, P = 0.007) and took longer to switch (400.9 days vs 330.7 days, P < 0.001) compared with platform initiators. Nearly 79% of platform initiators who switched went to another platform therapy. Approximately two thirds of patients who switched to a third DMT (n = 130) switched to another platform therapy. A total of 9% of natalizumab and platform initiators discontinued DMT within the 2 years. Most MS patients initiating DMT started on platform therapy. Natalizumab initiators tended to stay on index therapy, have fewer treatment gaps, and switch less than platform initiators in the 2 years after treatment initiation. Switching between platform therapies is common despite evidence that MS patients on platform therapy may benefit from switching to natalizumab. © 2013 Elsevier HS Journals, Inc. All rights reserved.

Economic impact of switching to fixed-dose combination therapy for Japanese hypertensive patients: a retrospective cost analysis

PubMed Central

2013-01-01

Background The prescription of fixed-dose combinations (FDC) of antihypertensive drugs has increased rapidly since the relaxation of the prescription-term restriction. In this study, we used the opportunity of this policy change in Japan as an instrument to assess the causal impact of switching to FDC on hypertensive treatment costs. Methods Claims data from 64 community pharmacies located in Tokyo were used to identify hypertensive patients under continuous treatment with angiotensin-receptor blockers (ARBs). Patients switching to FDC between December 2010 and April 2011 were compared to patients who did not receive FDC (control group). Changes in annual antihypertensive drug costs were compared using a difference-in-differences approach to adjust for patient characteristics and use of concomitant medication. Subpopulation analyses were also performed, taking into account pre-index treatment patterns and prescribers’ characteristics. Results There were 542 patients who switched to FDC and 9664 patients in the control group. No significant differences were observed between the 2 groups, except for antihypertensive drug use patterns before the policy change and prescribers’ characteristics. The switch to FDC was associated with an annual saving of 10,420 yen (US$112.0) in antihypertensive drug costs. Approximately 20% of the FDC patients, however, switched from ARB alone, and their drug costs increased by 2376 yen (US$25.5). Conclusions For hypertensive patients who required ARB-based combination therapy, switching to FDC drugs had a significant cost-saving effect. However, the policy change of relaxing the prescription-term restriction could encourage aggressive treatment, i.e., switching to a combination therapy from monotherapy, regardless of medical conditions. Further research is required to evaluate the possible negative aspects of FDC drugs. PMID:23552327

Micromachined mirrors for raster-scanning displays and optical fiber switches

NASA Astrophysics Data System (ADS)

Hagelin, Paul Merritt

Micromachines and micro-optics have the potential to shrink the size and cost of free-space optical systems, enabling a new generation of high-performance, compact projection displays and telecommunications equipment. In raster-scanning displays and optical fiber switches, a free-space optical beam can interact with multiple tilt- up micromirrors fabricated on a single substrate. The size, rotation angle, and flatness of the mirror surfaces determine the number of pixels in a raster-display or ports in an optical switch. Single-chip and two-chip optical raster display systems demonstrate static mirror curvature correction, an integrated electronic driver board, and dynamic micromirror performance. Correction for curvature caused by a stress gradient in the micromirror leads to resolution of 102 by 119 pixels in the single-chip display. The optical design of the two-chip display features in-situ mirror curvature measurement and adjustable image magnification with a single output lens. An electronic driver board synchronizes modulation of the optical source with micromirror actuation for the display of images. Dynamic off-axis mirror motion is shown to have minimal influence on resolution. The confocal switch, a free-space optical fiber cross- connect, incorporates micromirrors having a design similar to the image-refresh scanner. Two micromirror arrays redirect optical beams from an input fiber array to the output fibers. The switch architecture supports simultaneous switching of multiple wavelength channels. A 2x2 switch configuration, using single-mode optical fiber at 1550 mn, is demonstrated with insertion loss of -4.2 dB and cross-talk of -50.5 dB. The micromirrors have sufficient size and angular range for scaling to a 32x32 cross-connect switch that has low insertion-loss and low cross-talk.

Microwave switching power divider. [antenna feeds

NASA Technical Reports Server (NTRS)

Stockton, R. J.; Johnson, R. W. (Inventor)

1981-01-01

A pair of parallel, spaced-apart circular ground planes define a microwave cavity with multi-port microwave power distributing switching circuitry formed on opposite sides of a thin circular dielectric substrate disposed between the ground planes. The power distributing circuitry includes a conductive disk located at the center of the substrate and connected to a source of microwave energy. A high speed, low insertion loss switching diode and a dc blocking capacitor are connected in series between the outer end of a transmission line and an output port. A high impedance, microwave blocking dc bias choke is connected between each switching diode and a source of switching current. The switching source forward biases the diodes to couple microwave energy from the conductive disk to selected output ports and, to associated antenna elements connected to the output ports to form a synthesized antenna pattern.

Switching mechanism transition induced by annealing treatment in nonvolatile Cu/ZnO/Cu/ZnO/Pt resistive memory: From carrier trapping/detrapping to electrochemical metallization

NASA Astrophysics Data System (ADS)

Yang, Y. C.; Pan, F.; Zeng, F.; Liu, M.

2009-12-01

ZnO/Cu/ZnO trilayer films sandwiched between Cu and Pt electrodes were prepared for nonvolatile resistive memory applications. These structures show resistance switching under electrical bias both before and after a rapid thermal annealing (RTA) treatment, while it is found that the resistive switching effects in the two cases exhibit distinct characteristics. Compared with the as-fabricated device, the memory cell after RTA demonstrates remarkable device parameter improvements including lower threshold voltages, lower write current, and higher Roff/Ron ratio. A high-voltage forming process is avoided in the annealed device as well. Furthermore, the RTA treatment has triggered a switching mechanism transition from a carrier trapping/detrapping type to an electrochemical-redox-reaction-controlled conductive filament formation/rupture process, as indicated by different features in current-voltage characteristics. Both scanning electron microscopy observations and Auger electron spectroscopy depth profiles reveal that the Cu charge trapping layer in ZnO/Cu/ZnO disperses uniformly into the storage medium after RTA, while x-ray diffraction and x-ray photoelectron spectroscopy analyses demonstrate that the Cu atoms have lost electrons to become Cu2+ ions after dispersion. The above experimental facts indicate that the altered status of Cu in the ZnO/Cu/ZnO trilayer films during RTA treatment should be responsible for the switching mechanism transition. This study is envisioned to open the door for understanding the interrelation between different mechanisms that currently exist in the field of resistive memories.

Room temperature operation of electro-optical bistability in the edge-emitting tunneling-collector transistor laser

NASA Astrophysics Data System (ADS)

Feng, M.; Holonyak, N.; Wang, C. Y.

2017-09-01

Optical bistable devices are fundamental to digital photonics as building blocks of switches, logic gates, and memories in future computer systems. Here, we demonstrate both optical and electrical bistability and capability for switching in a single transistor operated at room temperature. The electro-optical hysteresis is explained by the interaction of electron-hole (e-h) generation and recombination dynamics with the cavity photon modulation in different switching paths. The switch-UP and switch-DOWN threshold voltages are determined by the rate difference of photon generation at the base quantum-well and the photon absorption via intra-cavity photon-assisted tunneling controlled by the collector voltage. Thus, the transistor laser electro-optical bistable switching is programmable with base current and collector voltage, and the basis for high speed optical logic processors.

Direct evidence on Ta-Metal Phases Igniting Resistive Switching in TaOx Thin Film

PubMed Central

Kyu Yang, Min; Ju, Hyunsu; Hwan Kim, Gun; Lee, Jeon-Kook; Ryu, Han-Cheol

2015-01-01

A Ta/TaOx/Pt stacked capacitor-like device for resistive switching was fabricated and examined. The tested device demonstrated stable resistive switching characteristics including uniform distribution of resistive switching operational parameters, highly promising endurance, and retention properties. To reveal the resistive switching mechanism of the device, micro structure analysis using high-resolution transmission electron microscope (HR-TEM) was performed. From the observation results, two different phases of Ta-metal clusters of cubic α-Ta and tetragonal β-Ta were founded in the amorphous TaOx mother-matrix after the device was switched from high resistance state (HRS) to low resistance state (LRS) by externally applied voltage bias. The observed Ta metal clusters unveiled the origin of the electric conduction paths in the TaOx thin film at the LRS. PMID:26365532

Direct evidence on Ta-Metal Phases Igniting Resistive Switching in TaOx Thin Film

NASA Astrophysics Data System (ADS)

Kyu Yang, Min; Ju, Hyunsu; Hwan Kim, Gun; Lee, Jeon-Kook; Ryu, Han-Cheol

2015-09-01

A Ta/TaOx/Pt stacked capacitor-like device for resistive switching was fabricated and examined. The tested device demonstrated stable resistive switching characteristics including uniform distribution of resistive switching operational parameters, highly promising endurance, and retention properties. To reveal the resistive switching mechanism of the device, micro structure analysis using high-resolution transmission electron microscope (HR-TEM) was performed. From the observation results, two different phases of Ta-metal clusters of cubic α-Ta and tetragonal β-Ta were founded in the amorphous TaOx mother-matrix after the device was switched from high resistance state (HRS) to low resistance state (LRS) by externally applied voltage bias. The observed Ta metal clusters unveiled the origin of the electric conduction paths in the TaOx thin film at the LRS.

Research in pulsed power plasma physics

NASA Astrophysics Data System (ADS)

Hinshelwood, David; Rose, David

1993-11-01

The research was conducted in support of light-ion-driven inertial confinement fusion (ICF) for the Department of Energy (DOE), and nuclear weapon effects simulation (NWES) for the Defense Nuclear Agency (DNA). Accomplishments related to ion beams include: development of a practical backup approach to ion beam transport; the first studies of ion-beam interaction with a neutral gas; initial investigations of a promising industrial application of ion beam technology; and detailed theoretical evaluation of several different ion beam transport schemes. Major accomplishments relating to opening switches include: the first direct measurement of the electron density in an opening switch; detailed studies of switch conduction-time scaling; evaluation of several different switch plasma sources; and extensive studies of switch performance into diode loads, leading to the development of a new (and now generally accepted) model of switch behavior.

Light modulated switches and radio frequency emitters

DOEpatents

Wilson, Mahlon T.; Tallerico, Paul J.

1982-01-01

The disclosure relates to a light modulated electron beam driven radiofrequency emitter. Pulses of light impinge on a photoemissive device which generates an electron beam having the pulse characteristics of the light. The electron beam is accelerated through a radiofrequency resonator which produces radiofrequency emission in accordance with the electron, hence, the light pulses.

From quantum to classical interactions between a free electron and a surface

NASA Astrophysics Data System (ADS)

Beierle, Peter James

Quantum theory is often cited as being one of the most empirically validated theories in terms of its predictive power and precision. These attributes have led to numerous scientific discoveries and technological advancements. However, the precise relationship between quantum and classical physics remains obscure. The prevailing description is known as decoherence theory, where classical physics emerges from a more general quantum theory through environmental interaction. Sometimes referred to as the decoherence program, it does not solve the quantum measurement problem. We believe experiments performed between the microscopic and macroscopic world may help finish the program. The following considers a free electron that interacts with a surface (the environment), providing a controlled decoherence mechanism. There are non-decohering interactions to be examined and quantified before the weaker decohering effects are filtered out. In the first experiment, an electron beam passes over a surface that's illuminated by low-power laser light. This induces a surface charge redistribution causing the electron deflection. This phenomenon's parameters are investigated. This system can be well understood in terms of classical electrodynamics, and the technological applications of this electron beam switch are considered. Such phenomena may mask decoherence effects. A second experiment tests decoherence theory by introducing a nanofabricated diffraction grating before the surface. The electron undergoes diffraction through the grating, but as the electron passes over the surface it's predicted by various physical models that the electron will lose its wave interference property. Image charge based models, which predict a larger loss of contrast than what is observed, are falsified (despite experiencing an image charge force). A theoretical study demonstrates how a loss of contrast may not be due to the irreversible process decoherence, but dephasing (a reversible process due to randomization of the wavefunction's phase). To resolve this ambiguity, a correlation function on an ensemble of diffraction patterns is analyzed after an electron undergoes either process in a path integral calculation. The diffraction pattern is successfully recovered for dephasing, but not for decoherence, thus verifying it as a potential tool in experimental studies to determine the nature of the observed process.

Fully programmable and scalable optical switching fabric for petabyte data center.

PubMed

Zhu, Zhonghua; Zhong, Shan; Chen, Li; Chen, Kai

2015-02-09

We present a converged EPS and OCS switching fabric for data center networks (DCNs) based on a distributed optical switching architecture leveraging both WDM & SDM technologies. The architecture is topology adaptive, well suited to dynamic and diverse *-cast traffic patterns. Compared to a typical folded-Clos network, the new architecture is more readily scalable to future multi-Petabyte data centers with 1000 + racks while providing a higher link bandwidth, reducing transceiver count by 50%, and improving cabling efficiency by more than 90%.

Individuals with Access and Functional Needs

MedlinePlus

... online tool helps people locate and access their electronic health records from a variety of sources. Plan ... Social Security or other regular benefits, switching to electronic payments is a simple, significant way to protect ...

Portable radiography system using a relativistic electron beam

DOEpatents

Hoeberling, Robert F.

1990-01-01

A portable radiographic generator is provided with an explosive magnetic flux compression generator producing the high voltage necessary to generate a relativistic electron beam. The relativistic electron beam is provided with target materials which generates the desired radiographic pulse. The magnetic flux compression generator may require at least two conventional explosively driven generators in series to obtain a desired output voltage of at least 1 MV. The cathode and anode configuration of the diode are selected to provide a switching action wherein a high impedance load is presented to the magnetic flux compression generator when the high voltage is being generated, and thereafter switching to a low impedance load to generate the relativistic electron beam. Magnetic flux compression generators can be explosively driven and provided in a relatively compact, portable form for use with the relativistic x-ray equipment.

Portable radiography system using a relativistic electron beam

DOEpatents

Hoeberling, R.F.

1987-09-22

A portable radiographic generator is provided with an explosive magnetic flux compression generator producing the high voltage necessary to generate a relativistic electron beam. The relativistic electron beam is provided with target materials which generates the desired radiographic pulse. The magnetic flux compression generator may require at least two conventional explosively driven generators in series to obtain a desired output voltage of at least 1 MV. The cathode and anode configuration of the diode are selected to provide a switching action wherein a high impedance load is presented to the magnetic flux compression generator when the high voltage is being generated, and thereafter switching to a low impedance load to generate the relativistic electron beam. Magnetic flux compression generators can be explosively driven and provided in a relatively compact, portable form for use with the relativistic x-ray equipment. 8 figs.

Redox regulation of mitochondrial proteins and proteomes by cysteine thiol switches.

PubMed

Nietzel, Thomas; Mostertz, Jörg; Hochgräfe, Falko; Schwarzländer, Markus

2017-03-01

Mitochondria are hotspots of cellular redox biochemistry. Respiration as a defining mitochondrial function is made up of a series of electron transfers that are ultimately coupled to maintaining the proton motive force, ATP production and cellular energy supply. The individual reaction steps involved require tight control and flexible regulation to maintain energy and redox balance in the cell under fluctuating demands. Redox regulation by thiol switching has been a long-standing candidate mechanism to support rapid adjustment of mitochondrial protein function at the posttranslational level. Here we review recent advances in our understanding of cysteine thiol switches in the mitochondrial proteome with a focus on their operation in vivo. We assess the conceptual basis for thiol switching in mitochondria and discuss to what extent insights gained from in vitro studies may be valid in vivo, considering thermodynamic, kinetic and structural constraints. We compare functional proteomic approaches that have been used to assess mitochondrial protein thiol switches, including thioredoxin trapping, redox difference gel electrophoresis (redoxDIGE), isotope-coded affinity tag (OxICAT) and iodoacetyl tandem mass tag (iodoTMT) labelling strategies. We discuss conditions that may favour active thiol switching in mitochondrial proteomes in vivo, and appraise recent advances in dissecting their impact using combinations of in vivo redox sensing and quantitative redox proteomics. Finally we focus on four central facets of mitochondrial biology, aging, carbon metabolism, energy coupling and electron transport, exemplifying the current emergence of a mechanistic understanding of mitochondrial regulation by thiol switching in living plants and animals. Copyright © 2016 Elsevier B.V. and Mitochondria Research Society. All rights reserved.

Recent Advances in Optically Controlled Bulk Semiconductor Switches

DTIC Science & Technology

1985-06-01

REO!NT AIJifl,NCES IN (FTICALIX ~1Ra.LW IILK SHttiaHlOCIOR swrrams L. Bovino , T. Burke, R. Youmans, M. Weiner, J. Carter U.S. Ar~ Electronics...fabrication of all of our optically activated switches. B.e.fer.enc.es. 1. L. Bovino , R. Youmans, T. Burke, M.Weiner, "Modulator Circuits Using Q...tically Activated Switches", Record of 16th Power Modulator SYJll>o- siurn, pp 235-239, June 1984. 2. M. Weiner, T. Burke, R. Youmans, L. Bovino , J

Memristive switching of MgO based magnetic tunnel junctions

NASA Astrophysics Data System (ADS)

Krzysteczko, Patryk; Reiss, Günter; Thomas, Andy

2009-09-01

Here we demonstrate that both, tunnel magnetoresistance (TMR) and resistive switching (RS), can be observed simultaneously in nanoscale magnetic tunnel junctions. The devices show bipolar RS of 6% and TMR ratios of about 100%. For each magnetic state, multiple resistive states are created depending on the bias history, which provides a method for multibit data storage and logic. The electronic transport measurements are discussed in the framework of a memristive system. Differently prepared MgO barriers are compared to gain insight into the switching mechanism.

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

Verheest, Frank, E-mail: frank.verheest@ugent.be; School of Chemistry and Physics, University of KwaZulu-Natal, Durban 4000; Hellberg, Manfred A., E-mail: hellberg@ukzn.ac.za

The propagation of arbitrary amplitude electron-acoustic solitons and double layers is investigated in a plasma containing cold positive ions, cool adiabatic and hot isothermal electrons, with the retention of full inertial effects for all species. For analytical tractability, the resulting Sagdeev pseudopotential is expressed in terms of the hot electron density, rather than the electrostatic potential. The existence domains for Mach numbers and hot electron densities clearly show that both rarefactive and compressive solitons can exist. Soliton limitations come from the cool electron sonic point, followed by the hot electron sonic point, until a range of rarefactive double layers occurs.more » Increasing the relative cool electron density further yields a switch to compressive double layers, which ends when the model assumptions break down. These qualitative results are but little influenced by variations in compositional parameters. A comparison with a Boltzmann distribution for the hot electrons shows that only the cool electron sonic point limit remains, giving higher maximum Mach numbers but similar densities, and a restricted range in relative hot electron density before the model assumptions are exceeded. The Boltzmann distribution can reproduce neither the double layer solutions nor the switch in rarefactive/compressive character or negative/positive polarity.« less

Room-Temperature Spin-Orbit Torque Switching Induced by a Topological Insulator

NASA Astrophysics Data System (ADS)

Han, Jiahao; Richardella, A.; Siddiqui, Saima A.; Finley, Joseph; Samarth, N.; Liu, Luqiao

2017-08-01

The strongly spin-momentum coupled electronic states in topological insulators (TI) have been extensively pursued to realize efficient magnetic switching. However, previous studies show a large discrepancy of the charge-spin conversion efficiency. Moreover, current-induced magnetic switching with TI can only be observed at cryogenic temperatures. We report spin-orbit torque switching in a TI-ferrimagnet heterostructure with perpendicular magnetic anisotropy at room temperature. The obtained effective spin Hall angle of TI is substantially larger than the previously studied heavy metals. Our results demonstrate robust charge-spin conversion in TI and provide a direct avenue towards applicable TI-based spintronic devices.

Three-terminal resistive switching memory in a transparent vertical-configuration device

NASA Astrophysics Data System (ADS)

Ungureanu, Mariana; Llopis, Roger; Casanova, Fèlix; Hueso, Luis E.

2014-01-01

The resistive switching phenomenon has attracted much attention recently for memory applications. It describes the reversible change in the resistance of a dielectric between two non-volatile states by the application of electrical pulses. Typical resistive switching memories are two-terminal devices formed by an oxide layer placed between two metal electrodes. Here, we report on the fabrication and operation of a three-terminal resistive switching memory that works as a reconfigurable logic component and offers an increased logic density on chip. The three-terminal memory device we present is transparent and could be further incorporated in transparent computing electronic technologies.

A Hybrid Converter for Improving Light Load Efficiency

NASA Astrophysics Data System (ADS)

Takahashi, Masaya; Nishijima, Kimihiro; Nagao, Michihiko; Sato, Terukazu; Nabeshima, Takashi

In order to reduce power consumption of electronic equipment in stand-by mode, idle-mode and sleep-mode, a simple efficiency improvement technique for switching regulator in light load region is proposed. In this technique, under the light load, the small switching elements in a MOSFET driver circuit are used instead of the switching elements in a main regulator circuit to reduce driving losses. Of course, under the load heavier than light load, the MOSFET driver drives the switching elements in the main regulator circuit. The efficiency of a 2.5V/5A prototype buck converter is improved from 47.1% to 72.7% by using the proposed technique.

Code-Switching and Vernacular Support: An Early Middle English Case Study

ERIC Educational Resources Information Center

Skaffari, Janne

2016-01-01

In the multilingual history of England, the period following the Norman Conquest in 1066 is a particularly intriguing phase, but its code-switching patterns have so far received little attention. The present article describes and analyses the multilingual practices evinced in London, British Library, MS Stowe 34, containing one instructional prose…

Intra- and Inter-Individual Variation in Self-Reported Code-Switching Patterns of Adult Multilinguals

ERIC Educational Resources Information Center

Dewaele, Jean-Marc; Li, Wei

2014-01-01

The present study is a large-scale quantitative analysis of intra-individual variation (linked to type of interlocutor) and inter-individual variation (linked to multilingualism, sociobiographical variables and three personality traits) in self-reported frequency of code-switching (CS) among 2116 multilinguals. We found a significant effect of…

Automated platform for determination of LEDs spatial radiation pattern

NASA Astrophysics Data System (ADS)

Vladescu, Marian; Vuza, Dan Tudor

2015-02-01

Nowadays technologies lead to remarkable properties of the light-emitting diodes (LEDs), making them attractive for more and more applications, such as: interior and exterior lighting, outdoor LED panels, traffic signals, automotive (tail and brake lights, backlighting in dashboard and switches), backlighting of display panels, LCD displays, symbols on switches, keyboards, graphic boards and measuring scales. Usually, LEDs are small light sources consisting of a chip placed into a package, which may bring additional optics to this encapsulated ensemble, resulting in a less or more complex spatial distribution of the light intensity, with particular radiation patterns. This paper presents an automated platform designed to allow a quick and accurate determination of the spatial radiation patterns of LEDs encapsulated in various packages. Keywords: LED, luminous

The electronic transport properties of defected bilayer sliding armchair graphene nanoribbons

NASA Astrophysics Data System (ADS)

Mohammadi, Amin; Haji-Nasiri, Saeed

2018-04-01

By applying non-equilibrium Green's functions (NEGF) in combination with tight-binding (TB) model, we investigate and compare the electronic transport properties of perfect and defected bilayer armchair graphene nanoribbons (BAGNRs) under finite bias. Two typical defects which are placed in the middle of top layer (i.e. single vacancy (SV) and stone wale (SW) defects) are examined. The results reveal that in both perfect and defected bilayers, the maximum current refers to β-AB, AA and α-AB stacking orders, respectively, since the intermolecular interactions are stronger in them. Moreover it is observed that a SV decreases the current in all stacking orders, but the effects of a SW defect is nearly unpredictable. Besides, we introduced a sequential switching behavior and the effects of defects on the switching performance is studied as well. We found that a SW defect can significantly improve the switching behavior of a bilayer system. Transmission spectrum, band structure, molecular energy spectrum and molecular projected self-consistent Hamiltonian (MPSH) are analyzed subsequently to understand the electronic transport properties of these bilayer devices which can be used in developing nano-scale bilayer systems.

Experimental Results from a Laser-Triggered, Gas-Insulated, Spark-Gap Switch

NASA Astrophysics Data System (ADS)

Camacho, J. F.; Ruden, E. L.; Domonkos, M. T.

2017-10-01

We are performing experiments on a laser-triggered spark-gap switch with the goal of studying the transition from photoionization to current conduction. The discharge of current through the switch is triggered by a focused 532-nm wavelength beam from a Q-switched Nd:YAG laser with a pulse duration of about 10 ns. The trigger pulse is delivered along the longitudinal axis of the switch, and the focal spot can be placed anywhere along the axis of the 5-mm, gas-insulated gap between the switch electrodes. The switch test bed is designed to support a variety of working gases (e.g., Ar, N2) over a range of pressures. Electrical and optical diagnostics are used to measure switch performance as a function of parameters such as charge voltage, trigger pulse energy, insulating gas pressure, and gas species. A Mach-Zehnder imaging interferometer system operating at 532 nm is being used to obtain interferograms of the discharge plasma in the switch. We are also developing a 1064-nm interferometry diagnostic in an attempt to measure plasma free electron and neutral gas density profiles simultaneously within the switch gap. Results from our most recent experiments will be presented.

Ternary gas mixture for diffuse discharge switch

DOEpatents

Christophorou, Loucas G.; Hunter, Scott R.

1988-01-01

A new diffuse discharge gas switch wherein a mixture of gases is used to take advantage of desirable properties of the respective gases. There is a conducting gas, an insulating gas, and a third gas that has low ionization energy resulting in a net increase in the number of electrons available to produce a current.

Blast-induced Mild Traumatic Brain Injury

DTIC Science & Technology

2010-01-01

concentration with agents such as psychostimulants, or improving compensatory strategies through cognitive- behavioral therapies. Pharmacological interventions...participate in educational activities and support groups. Some examples of general educational content include (1) compensatory strategies for impaired...or simple, ranging from electronic transmitters to trip wires, tilt switches, motion detectors, or thermal or pressure-sensitive switches. lEOs are

Flipping the Switch: Code-Switching from Text Speak to Standard English

ERIC Educational Resources Information Center

Turner, Kristen Hawley

2009-01-01

Because digital language represents such a large part of the primary discourse of today's adolescents, it is not surprising that the style of electronic communication is "seeping into their schoolwork." According to a recent study published by the Pew Internet and American Life Project, in partnership with the College Board's National Commission…

78 FR 75360 - Notice of Issuance of Final Determination Concerning Certain Ethernet Switches

Federal Register 2010, 2011, 2012, 2013, 2014

2013-12-11

... printed circuit board assembly (``PCBA''), chassis, top cover, power supply, and fans. The switches... printed circuit board is populated with various electronic components to make a PCBA. 2. The PCBA is... Singapore. You argue that without the EOS software, the units exported from Singapore lack the intelligence...

Research Update: Molecular electronics: The single-molecule switch and transistor

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

Sotthewes, Kai; Heimbuch, René, E-mail: r.heimbuch@utwente.nl; Kumar, Avijit

2014-01-01

In order to design and realize single-molecule devices it is essential to have a good understanding of the properties of an individual molecule. For electronic applications, the most important property of a molecule is its conductance. Here we show how a single octanethiol molecule can be connected to macroscopic leads and how the transport properties of the molecule can be measured. Based on this knowledge we have realized two single-molecule devices: a molecular switch and a molecular transistor. The switch can be opened and closed at will by carefully adjusting the separation between the electrical contacts and the voltage dropmore » across the contacts. This single-molecular switch operates in a broad temperature range from cryogenic temperatures all the way up to room temperature. Via mechanical gating, i.e., compressing or stretching of the octanethiol molecule, by varying the contact's interspace, we are able to systematically adjust the conductance of the electrode-octanethiol-electrode junction. This two-terminal single-molecule transistor is very robust, but the amplification factor is rather limited.« less

Electrical Conductance Tuning and Bistable Switching in Poly(N-vinylcarbazole)-Carbon Nanotube Composite Films.

PubMed

Liu, Gang; Ling, Qi-Dan; Teo, Eric Yeow Hwee; Zhu, Chun-Xiang; Chan, D Siu-Hung; Neoh, Koon-Gee; Kang, En-Tang

2009-07-28

By varying the carbon nanotube (CNT) content in poly(N-vinylcarbazole) (PVK) composite thin films, the electrical conductance behavior of an indium-tin oxide/PVK-CNT/aluminum (ITO/PVK-CNT/Al) sandwich structure can be tuned in a controlled manner. Distinctly different electrical conductance behaviors, such as (i) insulator behavior, (ii) bistable electrical conductance switching effects (write-once read-many-times (WORM) memory effect and rewritable memory effect), and (iii) conductor behavior, are discernible from the current density-voltage characteristics of the composite films. The turn-on voltage of the two bistable conductance switching devices decreases and the ON/OFF state current ratio of the WORM device increases with the increase in CNT content of the composite film. Both the WORM and rewritable devices are stable under a constant voltage stress or a continuous pulse voltage stress, with an ON/OFF state current ratio in excess of 10(3). The conductance switching effects of the composite films have been attributed to electron trapping in the CNTs of the electron-donating/hole-transporting PVK matrix.

Phase-change memory function of correlated electrons in organic conductors

NASA Astrophysics Data System (ADS)

Oike, H.; Kagawa, F.; Ogawa, N.; Ueda, A.; Mori, H.; Kawasaki, M.; Tokura, Y.

2015-01-01

Phase-change memory (PCM), a promising candidate for next-generation nonvolatile memories, exploits quenched glassy and thermodynamically stable crystalline states as reversibly switchable state variables. We demonstrate PCM functions emerging from a charge-configuration degree of freedom in strongly correlated electron systems. Nonvolatile reversible switching between a high-resistivity charge-crystalline (or charge-ordered) state and a low-resistivity quenched state, charge glass, is achieved experimentally via heat pulses supplied by optical or electrical means in organic conductors θ -(BEDT-TTF)2X . Switching that is one order of magnitude faster is observed in another isostructural material that requires faster cooling to kinetically avoid charge crystallization, indicating that the material's critical cooling rate can be useful guidelines for pursuing a faster correlated-electron PCM function.

Self-Assessment of Individual Differences in Language Switching

PubMed Central

Rodriguez-Fornells, Antoni; Krämer, Ulrike M.; Lorenzo-Seva, Urbano; Festman, Julia; Münte, Thomas F.

2012-01-01

Language switching is omnipresent in bilingual individuals. In fact, the ability to switch languages (code switching) is a very fast, efficient, and flexible process that seems to be a fundamental aspect of bilingual language processing. In this study, we aimed to characterize psychometrically self-perceived individual differences in language switching and to create a reliable measure of this behavioral pattern by introducing a bilingual switching questionnaire. As a working hypothesis based on the previous literature about code switching, we decomposed language switching into four constructs: (i) L1 switching tendencies (the tendency to switch to L1; L1-switch); (ii) L2 switching tendencies (L2-switch); (iii) contextual switch, which indexes the frequency of switches usually triggered by a particular situation, topic, or environment; and (iv) unintended switch, which measures the lack of intention and awareness of the language switches. A total of 582 Spanish–Catalan bilingual university students were studied. Twelve items were selected (three for each construct). The correlation matrix was factor-analyzed using minimum rank factor analysis followed by oblique direct oblimin rotation. The overall proportion of common variance explained by the four extracted factors was 0.86. Finally, to assess the external validity of the individual differences scored with the new questionnaire, we evaluated the correlations between these measures and several psychometric (language proficiency) and behavioral measures related to cognitive and attentional control. The present study highlights the importance of evaluating individual differences in language switching using self-assessment instruments when studying the interface between cognitive control and bilingualism. PMID:22291668

Delayed avalanche breakdown of high-voltage silicon diodes: Various structures exhibit different picosecond-range switching behavior

NASA Astrophysics Data System (ADS)

Brylevskiy, Viktor; Smirnova, Irina; Gutkin, Andrej; Brunkov, Pavel; Rodin, Pavel; Grekhov, Igor

2017-11-01

We present a comparative study of silicon high-voltage diodes exhibiting the effect of delayed superfast impact-ionization breakdown. The effect manifests itself in a sustainable picosecond-range transient from the blocking to the conducting state and occurs when a steep voltage ramp is applied to the p+-n-n+ diode in the reverse direction. Nine groups of diodes with graded and abrupt pn-junctions have been specially fabricated for this study by different techniques from different Si substrates. Additionally, in two groups of these structures, the lifetime of nonequilibrium carriers was intentionally reduced by electron irradiation. All diodes have identical geometrical parameters and similar stationary breakdown voltages. Our experimental setup allows measuring both device voltage and current during the kilovolt switching with time resolution better than 50 ps. Although all devices are capable of forming a front with kilovolt amplitude and 100 ps risetime in the in-series load, the structures with graded pn-junctions have anomalously large residual voltage. The Deep Level Transient Spectroscopy study of all diode structures has been performed in order to evaluate the effect of deep centers on device performance. It was found that the presence of deep-level electron traps negatively correlates with parameters of superfast switching, whereas a large concentration of recombination centers created by electron irradiation has virtually no influence on switching characteristics.

Electronic-To-Optical-To-Electronic Packet-Data Conversion

NASA Technical Reports Server (NTRS)

Monacos, Steve

1996-01-01

Space-time multiplexer (STM) cell-based communication system designed to take advantage of both high throughput attainable in optical transmission links and flexibility and functionality of electronic processing, storage, and switching. Long packets segmented and transmitted optically by wavelength-division multiplexing. Performs optoelectronic and protocol conversion between electronic "store-and-forward" protocols and optical "hot-potato" protocols.

Nanoelectromechanical digital logic circuits using curved cantilever switches with amorphous-carbon-coated contacts

NASA Astrophysics Data System (ADS)

Ayala, Christopher L.; Grogg, Daniel; Bazigos, Antonios; Bleiker, Simon J.; Fernandez-Bolaños, Montserrat; Niklaus, Frank; Hagleitner, Christoph

2015-11-01

Nanoelectromechanical (NEM) switches have the potential to complement or replace traditional CMOS transistors in the area of ultra-low-power digital electronics. This paper reports the demonstration of prototype circuits including the first 3-stage ring oscillator built using cell-level digital logic elements based on curved NEM switches. The ring oscillator core occupies an area of 30 μm × 10 μm using 6 NEM switches. Each NEM switch device has a footprint of 5 μm × 3 μm, an air gap of 60 μm and is coated with amorphous carbon (a-C) for reliable operation. The ring oscillator operates at a frequency of 6.7 MHz, and confirms the simulated inverter propagation delay of 25 ns. The successful fabrication and measurement of this demonstrator are key milestones on the way towards an optimized, scaled technology with sub-nanosecond switching times, lower operating voltages and VLSI implementation.

Design and analysis of compact MMIC switches utilising GaAs pHEMTs in 3D multilayer technology

NASA Astrophysics Data System (ADS)

Haris, Norshakila; Kyabaggu, Peter B. K.; Alim, Mohammad A.; Rezazadeh, Ali A.

2017-05-01

In this paper, we demonstrate for the first time the implementation of three-dimensional multilayer technology on GaAs-based pseudomorphic high electron mobility transistor (pHEMT) switches. Two types of pHEMT switches are considered, namely single-pole single-throw (SPST) and single-pole double-throw (SPDT). The design and analysis of the devices are demonstrated first through a simulation of the industry-recognised standard model, TriQuint’s Own Model—Level 3, developed by TriQuint Semiconductor, Inc. From the simulation analysis, three optimised SPST and SPDT pHEMT switches which can address applications ranging from L to X bands, are fabricated and tested. The performance of the pHEMT switches using multilayer technology are comparable to those of the current state-of-the-art pHEMT switches, while simultaneously offering compact circuits with the advantages of integration with other MMIC components.

Kinetic factors determining conducting filament formation in solid polymer electrolyte based planar devices

NASA Astrophysics Data System (ADS)

Krishnan, Karthik; Aono, Masakazu; Tsuruoka, Tohru

2016-07-01

Resistive switching characteristics and conducting filament formation dynamics in solid polymer electrolyte (SPE) based planar-type atomic switches, with opposing active Ag and inert Pt electrodes, have been investigated by optimizing the device configuration and experimental parameters such as the gap distance between the electrodes, the salt inclusion in the polymer matrix, and the compliance current applied in current-voltage measurements. The high ionic conductivities of SPE enabled us to make scanning electron microscopy observations of the filament formation processes in the sub-micrometer to micrometer ranges. It was found that switching behaviour and filament growth morphology depend strongly on several kinetic factors, such as the redox reaction rate at the electrode-polymer interfaces, ion mobility in the polymer matrix, electric field strength, and the reduction sites for precipitation. Different filament formations, resulting from unidirectional and dendritic growth behaviours, can be controlled by tuning specified parameters, which in turn improves the stability and performance of SPE-based devices.Resistive switching characteristics and conducting filament formation dynamics in solid polymer electrolyte (SPE) based planar-type atomic switches, with opposing active Ag and inert Pt electrodes, have been investigated by optimizing the device configuration and experimental parameters such as the gap distance between the electrodes, the salt inclusion in the polymer matrix, and the compliance current applied in current-voltage measurements. The high ionic conductivities of SPE enabled us to make scanning electron microscopy observations of the filament formation processes in the sub-micrometer to micrometer ranges. It was found that switching behaviour and filament growth morphology depend strongly on several kinetic factors, such as the redox reaction rate at the electrode-polymer interfaces, ion mobility in the polymer matrix, electric field strength, and the reduction sites for precipitation. Different filament formations, resulting from unidirectional and dendritic growth behaviours, can be controlled by tuning specified parameters, which in turn improves the stability and performance of SPE-based devices. Electronic supplementary information (ESI) available. See DOI: 10.1039/c6nr00569a

Trench formation in <110> silicon for millimeter-wave switching device

NASA Astrophysics Data System (ADS)

Datta, P.; Kumar, Praveen; Nag, Manoj; Bhattacharya, D. K.; Khosla, Y. P.; Dahiya, K. K.; Singh, D. V.; Venkateswaran, R.; Kumar, Devender; Kesavan, R.

1999-11-01

Anisotropic etching using alkaline solution has been adopted to form trenches in silicon while fabricating surface oriented bulk window SPST switches. An array pattern has been etched on silicon with good control on depth of trenches. KOH-water solution is seen to yield a poor surface finish. Use of too much of additive like isopropyl alcohol improves the surface condition but distorts the array pattern due to loss of anisotropy. However, controlled use of this additive during the last phase of trench etching is found to produce trenched arrays with desired depth, improved surface finish and minimum distortion of lateral dimensions.

The formation of the light-sensing compartment of cone photoreceptors coincides with a transcriptional switch

PubMed Central

Daum, Janine M; Keles, Özkan; Holwerda, Sjoerd JB; Kohler, Hubertus; Rijli, Filippo M

2017-01-01

High-resolution daylight vision is mediated by cone photoreceptors. The molecular program responsible for the formation of their light sensor, the outer segment, is not well understood. We correlated daily changes in ultrastructure and gene expression in postmitotic mouse cones, between birth and eye opening, using serial block-face electron microscopy (EM) and RNA sequencing. Outer segments appeared rapidly at postnatal day six and their appearance coincided with a switch in gene expression. The switch affected over 14% of all expressed genes. Genes that switched off were rich in transcription factors and neurogenic genes. Those that switched on contained genes relevant for cone function. Chromatin rearrangements in enhancer regions occurred before the switch was completed, but not after. We provide a resource comprised of correlated EM, RNAseq, and ATACseq data, showing that the growth of a key compartment of a postmitotic cell involves an extensive switch in gene expression and chromatin accessibility. PMID:29106373

Evaluation of Fast Switching Diode 1N4448 Over a Wide Temperature Range

NASA Technical Reports Server (NTRS)

Boomer, Kristen; Damron, James; Gray, Josh; Hammoud, Ahmad

2017-01-01

Electronic parts used in the design of power systems geared for space applications are often exposed to extreme temperatures and thermal cycling. Limited data exist on the performance and reliability of commercial-off-the-shelf (COTS) electronic parts at temperatures beyond the manufacturers specified operating temperature range. This report summarizes preliminary results obtained on the evaluation of automotive-grade, fast switching diodes over a wide temperature range and thermal cycling. The investigations were carried out to establish a baseline on functionality of these diodes and to determine suitability for use outside their recommended temperature limits.

The switching behaviors induced by torsion angle in a diblock co-oligomer molecule with tailoring graphene nanoribbon electrodes

NASA Astrophysics Data System (ADS)

Yang, Aiyun; Xia, Caijuan; Zhang, Boqun; Wang, Jun; Su, Yaoheng; Tu, Zheyan

2018-02-01

By applying first-principles method based on density functional theory combined with nonequilibrium Green’s function, we investigate the effect of torsion angle on the electronic transport properties in dipyrimidinyl-diphenyl co-oligomer molecular device with tailoring graphene nanoribbon electrodes. The results show that the torsion angle plays an important role on the electronic transport properties of the molecular device. When the torsion angle rotates from 0∘ to 90∘, the molecular devices exhibit very different current-voltage characteristics which can realize the on and off states of the molecular switch.

Effect of density of localized states on the ovonic threshold switching characteristics of the amorphous GeSe films

NASA Astrophysics Data System (ADS)

Ahn, Hyung-Woo; Seok Jeong, Doo; Cheong, Byung-ki; Lee, Hosuk; Lee, Hosun; Kim, Su-dong; Shin, Sang-Yeol; Kim, Donghwan; Lee, Suyoun

2013-07-01

We investigated the effect of nitrogen (N) doping on the threshold voltage of an ovonic threshold switching device using amorphous GeSe. Using the spectroscopic ellipsometry, we found that the addition of N brought about significant changes in electronic structure of GeSe, such as the density of localized states and the band gap energy. Besides, it was observed that the characteristics of OTS devices strongly depended on the doping of N, which could be attributed to those changes in electronic structure suggesting a method to modulate the threshold voltage of the device.

Shuttle-promoted nano-mechanical current switch

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

Song, Taegeun, E-mail: tsong@ictp.it; Kiselev, Mikhail N.; Gorelik, Leonid Y.

2015-09-21

We investigate electron shuttling in three-terminal nanoelectromechanical device built on a movable metallic rod oscillating between two drains. The device shows a double-well shaped electromechanical potential tunable by a source-drain bias voltage. Four stationary regimes controllable by the bias are found for this device: (i) single stable fixed point, (ii) two stable fixed points, (iii) two limit cycles, and (iv) single limit cycle. In the presence of perpendicular magnetic field, the Lorentz force makes possible switching from one electromechanical state to another. The mechanism of tunable transitions between various stable regimes based on the interplay between voltage controlled electromechanical instabilitymore » and magnetically controlled switching is suggested. The switching phenomenon is implemented for achieving both a reliable active current switch and sensoring of small variations of magnetic field.« less

Evaluation of resistive switching properties of Si-rich oxide embedded with Ti nanodots by applying constant voltage and current

NASA Astrophysics Data System (ADS)

Ohta, Akio; Kato, Yusuke; Ikeda, Mitsuhisa; Makihara, Katsunori; Miyazaki, Seiichi

2018-06-01

We have studied the resistive switching behaviors of electron beam (EB) evaporated Si-rich oxide (SiO x ) sandwiched between Ni electrodes by applying a constant voltage and current. Additionally, the impact of Ti nanodots (NDs) embedded into SiO x on resistive switching behaviors was investigated because it is expected that NDs can trigger the formation of a conductive filament path in SiO x . The resistive switching behaviors of SiO x show that the response time during resistance switching was decreased by increasing the applied constant current or constant voltage. It was found that Ti-NDs in SiO x enhance the conductive filament path formation owing to electric field concentration by Ti-NDs.

Teaching Behavioral Modeling and Simulation Techniques for Power Electronics Courses

ERIC Educational Resources Information Center

Abramovitz, A.

2011-01-01

This paper suggests a pedagogical approach to teaching the subject of behavioral modeling of switch-mode power electronics systems through simulation by general-purpose electronic circuit simulators. The methodology is oriented toward electrical engineering (EE) students at the undergraduate level, enrolled in courses such as "Power…

16 CFR 1610.5 - Test apparatus and materials.

Code of Federal Regulations, 2012 CFR

2012-01-01

... electronic circuits, in addition to miscellaneous custom made cams and rods, shock absorbing linkages, and... burn time to 0.1 second. An electronic or mechanical timer can be used to record the burn time, and electro-mechanical devices (i.e., servo-motors, solenoids, micro-switches, and electronic circuits, in...

7 CFR 1770.15 - Supplementary accounts required of all borrowers.

Code of Federal Regulations, 2012 CFR

2012-01-01

... Switching—Circuit. 2212.2 2212.2 Digital Electronic Switching—Packet. 2230.11 Central Office Transmission... Retirement Work in Progress. Current Liabilities 2232.1 2232.1 Circuit Equipment—Electronic. 2232.2 2232.2... Expense—Circuit. 6212.2 6212.2 Digital Electronic Switching Expense—Packet. 6230.11 Radio Systems Expense...

16 CFR 1610.5 - Test apparatus and materials.

Code of Federal Regulations, 2014 CFR

2014-01-01

... electronic circuits, in addition to miscellaneous custom made cams and rods, shock absorbing linkages, and... burn time to 0.1 second. An electronic or mechanical timer can be used to record the burn time, and electro-mechanical devices (i.e., servo-motors, solenoids, micro-switches, and electronic circuits, in...

7 CFR 1770.15 - Supplementary accounts required of all borrowers.

Code of Federal Regulations, 2014 CFR

2014-01-01

... Switching—Circuit. 2212.2 2212.2 Digital Electronic Switching—Packet. 2230.11 Central Office Transmission... Retirement Work in Progress. Current Liabilities 2232.1 2232.1 Circuit Equipment—Electronic. 2232.2 2232.2... Expense—Circuit. 6212.2 6212.2 Digital Electronic Switching Expense—Packet. 6230.11 Radio Systems Expense...

7 CFR 1770.15 - Supplementary accounts required of all borrowers.

Code of Federal Regulations, 2011 CFR

2011-01-01

... Switching—Circuit. 2212.2 2212.2 Digital Electronic Switching—Packet. 2230.11 Central Office Transmission... Retirement Work in Progress. Current Liabilities 2232.1 2232.1 Circuit Equipment—Electronic. 2232.2 2232.2... Expense—Circuit. 6212.2 6212.2 Digital Electronic Switching Expense—Packet. 6230.11 Radio Systems Expense...

16 CFR § 1610.5 - Test apparatus and materials.

Code of Federal Regulations, 2013 CFR

2013-01-01

... electronic circuits, in addition to miscellaneous custom made cams and rods, shock absorbing linkages, and... burn time to 0.1 second. An electronic or mechanical timer can be used to record the burn time, and electro-mechanical devices (i.e., servo-motors, solenoids, micro-switches, and electronic circuits, in...

A Framework for Model-Based Diagnostics and Prognostics of Switched-Mode Power Supplies

DTIC Science & Technology

2014-10-02

system. Some highlights of the work are included but not only limited to the following aspects: first, the methodology is based on electronic ... electronic health management, with the goal of expanding the realm of electronic diagnostics and prognostics. 1. INTRODUCTION Electronic systems such...as electronic controls, onboard computers, communications, navigation and radar perform many critical functions in onboard military and commercial

Monolithic, High-Speed Fiber-Optic Switching Array for Lidar

NASA Technical Reports Server (NTRS)

Suckow, Will; Roberts, Tony; Switzer, Gregg; Terwilliger, Chelle

2011-01-01

Current fiber switch technologies use mechanical means to redirect light beams, resulting in slow switch time, as well as poor reliability due to moving parts wearing out quickly at high speeds. A non-mechanical ability to switch laser output into one of multiple fibers within a fiber array can provide significant power, weight, and costs savings to an all-fiber system. This invention uses an array of crystals that act as miniature prisms to redirect light as an electric voltage changes the prism s properties. At the heart of the electro-optic fiber-optic switch is an electro- optic crystal patterned with tiny prisms that can deflect the beam from the input fiber into any one of the receiving fibers arranged in a linear array when a voltage is applied across the crystal. Prism boundaries are defined by a net dipole moment in the crystal lattice that has been poled opposite to the surrounding lattice fabricated using patterned, removable microelectrodes. When a voltage is applied across the crystal, the resulting electric field changes the index of refraction within the prism boundaries relative to the surrounding substrate, causing light to deflect slightly according to Snell s Law. There are several materials that can host the necessary monolithic poled pattern (including, but not limited to, SLT, KTP, LiNbO3, and Mg:LiNbO3). Be cause this is a solid-state system without moving parts, it is very fast, and does not wear down easily. This invention is applicable to all fiber networks, as well as industries that use such networks. The unit comes in a compact package, can handle both low and high voltages, and has a high reliability (100,000 hours without maintenance).

Adélie penguin foraging location predicted by tidal regime switching.

PubMed

Oliver, Matthew J; Irwin, Andrew; Moline, Mark A; Fraser, William; Patterson, Donna; Schofield, Oscar; Kohut, Josh

2013-01-01

Penguin foraging and breeding success depend on broad-scale environmental and local-scale hydrographic features of their habitat. We investigated the effect of local tidal currents on a population of Adélie penguins on Humble Is., Antarctica. We used satellite-tagged penguins, an autonomous underwater vehicle, and historical tidal records to model of penguin foraging locations over ten seasons. The bearing of tidal currents did not oscillate daily, but rather between diurnal and semidiurnal tidal regimes. Adélie penguins foraging locations changed in response to tidal regime switching, and not to daily tidal patterns. The hydrography and foraging patterns of Adélie penguins during these switching tidal regimes suggest that they are responding to changing prey availability, as they are concentrated and dispersed in nearby Palmer Deep by variable tidal forcing on weekly timescales, providing a link between local currents and the ecology of this predator.

Adélie Penguin Foraging Location Predicted by Tidal Regime Switching

PubMed Central

Oliver, Matthew J.; Irwin, Andrew; Moline, Mark A.; Fraser, William; Patterson, Donna; Schofield, Oscar; Kohut, Josh

2013-01-01

Penguin foraging and breeding success depend on broad-scale environmental and local-scale hydrographic features of their habitat. We investigated the effect of local tidal currents on a population of Adélie penguins on Humble Is., Antarctica. We used satellite-tagged penguins, an autonomous underwater vehicle, and historical tidal records to model of penguin foraging locations over ten seasons. The bearing of tidal currents did not oscillate daily, but rather between diurnal and semidiurnal tidal regimes. Adélie penguins foraging locations changed in response to tidal regime switching, and not to daily tidal patterns. The hydrography and foraging patterns of Adélie penguins during these switching tidal regimes suggest that they are responding to changing prey availability, as they are concentrated and dispersed in nearby Palmer Deep by variable tidal forcing on weekly timescales, providing a link between local currents and the ecology of this predator. PMID:23383091

Analyte-driven switching of DNA charge transport: de novo creation of electronic sensors for an early lung cancer biomarker.

PubMed

Thomas, Jason M; Chakraborty, Banani; Sen, Dipankar; Yu, Hua-Zhong

2012-08-22

A general approach is described for the de novo design and construction of aptamer-based electrochemical biosensors, for potentially any analyte of interest (ranging from small ligands to biological macromolecules). As a demonstration of the approach, we report the rapid development of a made-to-order electronic sensor for a newly reported early biomarker for lung cancer (CTAP III/NAP2). The steps include the in vitro selection and characterization of DNA aptamer sequences, design and biochemical testing of wholly DNA sensor constructs, and translation to a functional electrode-bound sensor format. The working principle of this distinct class of electronic biosensors is the enhancement of DNA-mediated charge transport in response to analyte binding. We first verify such analyte-responsive charge transport switching in solution, using biochemical methods; successful sensor variants were then immobilized on gold electrodes. We show that using these sensor-modified electrodes, CTAP III/NAP2 can be detected with both high specificity and sensitivity (K(d) ~1 nM) through a direct electrochemical reading. To investigate the underlying basis of analyte binding-induced conductivity switching, we carried out Förster Resonance Energy Transfer (FRET) experiments. The FRET data establish that analyte binding-induced conductivity switching in these sensors results from very subtle structural/conformational changes, rather than large scale, global folding events. The implications of this finding are discussed with respect to possible charge transport switching mechanisms in electrode-bound sensors. Overall, the approach we describe here represents a unique design principle for aptamer-based electrochemical sensors; its application should enable rapid, on-demand access to a class of portable biosensors that offer robust, inexpensive, and operationally simplified alternatives to conventional antibody-based immunoassays.

A novel graphene oxide-polyimide as optical waveguide material: Synthesis and thermo-optic switch properties

NASA Astrophysics Data System (ADS)

Cao, Tianlin; Zhao, Fanyu; Da, Zulin; Qiu, Fengxian; Yang, Dongya; Guan, Yijun; Cao, Guorong; Zhao, Zerun; Li, Jiaxin; Guo, Xiaotong

2016-10-01

In this work, a novel graphene oxide-polyimide (GOPI) as optical waveguide material was prepared. The structure, mechanical, thermal property and morphology of the GOPI was characterized by using fourier transform infrared, UV-visible spectroscopy, near-infrared spectrum, thermogravimetric analysis, differential scanning calorimetry, scanning electron microscope and transmission electron microscopy. The thermo-optic coefficients (dn/dT) are -9.16 × 10-4 (532 nm), -7.56 × 10-4 (650 nm) and -4.82 × 10-4 (850 nm) °C-1, respectively. Based on the thermo-optic effect of prepared GOPI as waveguide material, a Y-branch with branching angle of 0.143° and Mach-Zehnder thermo-optic switches were designed. Using finite difference beam propagation method (FD-BPM) method, the simulation results such as power consumptions and response times of two different thermo-optic switches were obtained.

Active Control of Charge Density Waves at Degenerate Semiconductor Interfaces

NASA Astrophysics Data System (ADS)

Vinnakota, Raj; Genov, Dentcho

We present numerical modeling of an active electronically controlled highly confined charge-density waves, i.e. surface plasmon polaritons (SPPs) at the metallurgic interfaces of degenerate semiconductor materials. An electro-optic switching element for fully-functional plasmonic circuits based on p-n junction semiconductor Surface Plasmon Polariton (SPP) waveguide is shown. Two figures of merits are introduced and parametric study has been performed identifying the device optimal operation range. The Indium Gallium Arsenide (In0.53Ga0.47As) is identified as the best semiconductor material for the device providing high optical confinement, reduced system size and fast operation. The electro-optic SPP switching element is shown to operate at signal modulation up to -24dB and switching rates surpassing 100GHz, thus potentially providing a new pathway toward bridging the gap between electronic and photonic devices. The current work is funded by the NSF EPSCoR CIMM project under award #OIA-1541079.

Layered memristive and memcapacitive switches for printable electronics

NASA Astrophysics Data System (ADS)

Bessonov, Alexander A.; Kirikova, Marina N.; Petukhov, Dmitrii I.; Allen, Mark; Ryhänen, Tapani; Bailey, Marc J. A.

2015-02-01

Novel computing technologies that imitate the principles of biological neural systems may offer low power consumption along with distinct cognitive and learning advantages. The development of reliable memristive devices capable of storing multiple states of information has opened up new applications such as neuromorphic circuits and adaptive systems. At the same time, the explosive growth of the printed electronics industry has expedited the search for advanced memory materials suitable for manufacturing flexible devices. Here, we demonstrate that solution-processed MoOx/MoS2 and WOx/WS2 heterostructures sandwiched between two printed silver electrodes exhibit an unprecedentedly large and tunable electrical resistance range from 102 to 108 Ω combined with low programming voltages of 0.1-0.2 V. The bipolar resistive switching, with a concurrent capacitive contribution, is governed by an ultrathin (<3 nm) oxide layer. With strong nonlinearity in switching dynamics, different mechanisms of synaptic plasticity are implemented by applying a sequence of electrical pulses.

A liquid lens switching-based motionless variable fiber-optic delay line

NASA Astrophysics Data System (ADS)

Khwaja, Tariq Shamim; Reza, Syed Azer; Sheikh, Mumtaz

2018-05-01

We present a Variable Fiber-Optic Delay Line (VFODL) module capable of imparting long variable delays by switching an input optical/RF signal between Single Mode Fiber (SMF) patch cords of different lengths through a pair of Electronically Controlled Tunable Lenses (ECTLs) resulting in a polarization-independent operation. Depending on intended application, the lengths of the SMFs can be chosen accordingly to achieve the desired VFODL operation dynamic range. If so desired, the state of the input signal polarization can be preserved with the use of commercially available polarization-independent ECTLs along with polarization-maintaining SMFs (PM-SMFs), resulting in an output polarization that is identical to the input. An ECTL-based design also improves power consumption and repeatability. The delay switching mechanism is electronically-controlled, involves no bulk moving parts, and can be fully-automated. The VFODL module is compact due to the use of small optical components and SMFs that can be packaged compactly.

Low-frequency (< 10 kHz) surface magnetic energy losses measured with polarized secondary electrons (abstract)

NASA Astrophysics Data System (ADS)

Woods, J.; O'Handley, R. C.

1990-05-01

The polarization of low-energy secondary electrons emitted from iron- and cobalt-based amorphous melt-spun ribbons is measured as a function of the applied in-plane magnetic field yielding surface hysteresis loops. The polarization is measured in real time up to a frequency of 10 kHz and hysteresis loops are displayed on an oscilloscope. The bulk losses are measured on the same samples in the same configuration with a secondary winding. The area of the loop (energy loss/cycle) is measured as a function of applied magnetic field switching rate for both the surface polarization and bulk magnetization measurements. The surface loss per cycle increases linearly with the switching rate and the bulk loss per cycle increases much more slowly with switching rate. This is the first discrimination of bulk and surface losses we are aware of.

An electron transfer driven magnetic switch: ferromagnetic exchange and spin delocalization in iron verdazyl complexes

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

Brook, David J. R.; Fleming, Connor; Chung, Dorothy

A single electron reduction of an iron bis(verdazyl) complex results in a large change in spin multiplicity resulting from a combination of spin crossover and exceptionally strong ferromagnetic exchange.

An electron transfer driven magnetic switch: ferromagnetic exchange and spin delocalization in iron verdazyl complexes

DOE PAGES

Brook, David J. R.; Fleming, Connor; Chung, Dorothy; ...

2018-01-01

A single electron reduction of an iron bis(verdazyl) complex results in a large change in spin multiplicity resulting from a combination of spin crossover and exceptionally strong ferromagnetic exchange.

Patterns of Treatment Switching in Multiple Sclerosis Therapies in US Patients Active on Social Media: Application of Social Media Content Analysis to Health Outcomes Research.

PubMed

Risson, Valéry; Saini, Deepanshu; Bonzani, Ian; Huisman, Alice; Olson, Melvin

2016-03-17

Social media analysis has rarely been applied to the study of specific questions in outcomes research. The aim was to test the applicability of social media analysis to outcomes research using automated listening combined with filtering and analysis of data by specialists. After validation, the process was applied to the study of patterns of treatment switching in multiple sclerosis (MS). A comprehensive listening and analysis process was developed that blended automated listening with filtering and analysis of data by life sciences-qualified analysts and physicians. The population was patients with MS from the United States. Data sources were Facebook, Twitter, blogs, and online forums. Sources were searched for mention of specific oral, injectable, and intravenous (IV) infusion treatments. The representativeness of the social media population was validated by comparison with community survey data and with data from three large US administrative claims databases: MarketScan, PharMetrics Plus, and Department of Defense. A total of 10,260 data points were sampled for manual review: 3025 from Twitter, 3771 from Facebook, 2773 from Internet forums, and 691 from blogs. The demographics of the social media population were similar to those reported from community surveys and claims databases. Mean age was 39 (SD 11) years and 14.56% (326/2239) of the population was older than 50 years. Women, patients aged 30 to 49 years, and those diagnosed for more than 10 years were represented by more data points than other patients were. Women also accounted for a large majority (82.6%, 819/991) of reported switches. Two-fifths of switching patients had lived with their disease for more than 10 years since diagnosis. Most reported switches (55.05%, 927/1684) were from injectable to oral drugs with switches from IV therapies to orals the second largest switch (15.38%, 259/1684). Switches to oral drugs accounted for more than 80% (927/1114) of the switches away from injectable therapies. Four reasons accounted for more than 90% of all switches: severe side effects, lack of efficacy, physicians' advice, and greater ease of use. Side effects were the main reason for switches to oral or to injectable therapies and search for greater efficacy was the most important factor in switches to IV therapies. Cost of medication was the reason for switching in less than 0.5% of patients. Social intelligence can be applied to outcomes research with power to analyze MS patients' personal experiences of treatments and to chart the most common reasons for switching between therapies.

A comparative study of different methods for calculating electronic transition rates

NASA Astrophysics Data System (ADS)

Kananenka, Alexei A.; Sun, Xiang; Schubert, Alexander; Dunietz, Barry D.; Geva, Eitan

2018-03-01

We present a comprehensive comparison of the following mixed quantum-classical methods for calculating electronic transition rates: (1) nonequilibrium Fermi's golden rule, (2) mixed quantum-classical Liouville method, (3) mean-field (Ehrenfest) mixed quantum-classical method, and (4) fewest switches surface-hopping method (in diabatic and adiabatic representations). The comparison is performed on the Garg-Onuchic-Ambegaokar benchmark charge-transfer model, over a broad range of temperatures and electronic coupling strengths, with different nonequilibrium initial states, in the normal and inverted regimes. Under weak to moderate electronic coupling, the nonequilibrium Fermi's golden rule rates are found to be in good agreement with the rates obtained via the mixed quantum-classical Liouville method that coincides with the fully quantum-mechanically exact results for the model system under study. Our results suggest that the nonequilibrium Fermi's golden rule can serve as an inexpensive yet accurate alternative to Ehrenfest and the fewest switches surface-hopping methods.

Conformational gating of DNA conductance

PubMed Central

Artés, Juan Manuel; Li, Yuanhui; Qi, Jianqing; Anantram, M. P.; Hihath, Joshua

2015-01-01

DNA is a promising molecule for applications in molecular electronics because of its unique electronic and self-assembly properties. Here we report that the conductance of DNA duplexes increases by approximately one order of magnitude when its conformation is changed from the B-form to the A-form. This large conductance increase is fully reversible, and by controlling the chemical environment, the conductance can be repeatedly switched between the two values. The conductance of the two conformations displays weak length dependencies, as is expected for guanine-rich sequences, and can be fit with a coherence-corrected hopping model. These results are supported by ab initio electronic structure calculations that indicate that the highest occupied molecular orbital is more disperse in the A-form DNA case. These results demonstrate that DNA can behave as a promising molecular switch for molecular electronics applications and also provide additional insights into the huge dispersion of DNA conductance values found in the literature. PMID:26648400

Conformational gating of DNA conductance.

PubMed

Artés, Juan Manuel; Li, Yuanhui; Qi, Jianqing; Anantram, M P; Hihath, Joshua

2015-12-09

DNA is a promising molecule for applications in molecular electronics because of its unique electronic and self-assembly properties. Here we report that the conductance of DNA duplexes increases by approximately one order of magnitude when its conformation is changed from the B-form to the A-form. This large conductance increase is fully reversible, and by controlling the chemical environment, the conductance can be repeatedly switched between the two values. The conductance of the two conformations displays weak length dependencies, as is expected for guanine-rich sequences, and can be fit with a coherence-corrected hopping model. These results are supported by ab initio electronic structure calculations that indicate that the highest occupied molecular orbital is more disperse in the A-form DNA case. These results demonstrate that DNA can behave as a promising molecular switch for molecular electronics applications and also provide additional insights into the huge dispersion of DNA conductance values found in the literature.

Developmental Control of Cell-Cycle Compensation Provides a Switch for Patterned Mitosis at the Onset of Chordate Neurulation.

PubMed

Ogura, Yosuke; Sasakura, Yasunori

2016-04-18

During neurulation of chordate ascidians, the 11th mitotic division within the epidermal layer shows a posterior-to-anterior wave that is precisely coordinated with the unidirectional progression of the morphogenetic movement. Here we show that the first sign of this patterned mitosis is an asynchronous anterior-to-posterior S-phase length and that mitotic synchrony is reestablished by a compensatory asynchronous G2-phase length. Live imaging combined with genetic experiments demonstrated that compensatory G2-phase regulation requires transcriptional activation of the G2/M regulator cdc25 by the patterning genes GATA and AP-2. The downregulation of GATA and AP-2 at the onset of neurulation leads to loss of compensatory G2-phase regulation and promotes the transition to patterned mitosis. We propose that such developmentally regulated cell-cycle compensation provides an abrupt switch to spatially patterned mitosis in order to achieve the coordination between mitotic timing and morphogenesis. Copyright © 2016 Elsevier Inc. All rights reserved.

Fundamental physics issues of multilevel logic in developing a parallel processor.

NASA Astrophysics Data System (ADS)

Bandyopadhyay, Anirban; Miki, Kazushi

2007-06-01

In the last century, On and Off physical switches, were equated with two decisions 0 and 1 to express every information in terms of binary digits and physically realize it in terms of switches connected in a circuit. Apart from memory-density increase significantly, more possible choices in particular space enables pattern-logic a reality, and manipulation of pattern would allow controlling logic, generating a new kind of processor. Neumann's computer is based on sequential logic, processing bits one by one. But as pattern-logic is generated on a surface, viewing whole pattern at a time is a truly parallel processing. Following Neumann's and Shannons fundamental thermodynamical approaches we have built compatible model based on series of single molecule based multibit logic systems of 4-12 bits in an UHV-STM. On their monolayer multilevel communication and pattern formation is experimentally verified. Furthermore, the developed intelligent monolayer is trained by Artificial Neural Network. Therefore fundamental weak interactions for the building of truly parallel processor are explored here physically and theoretically.

Functions of Code-Switching among Iranian Advanced and Elementary Teachers and Students

ERIC Educational Resources Information Center

Momenian, Mohammad; Samar, Reza Ghafar

2011-01-01

This paper reports on the findings of a study carried out on the advanced and elementary teachers' and students' functions and patterns of code-switching in Iranian English classrooms. This concept has not been adequately examined in L2 (second language) classroom contexts than in outdoor natural contexts. Therefore, besides reporting on the…

Contralateral Disconnection of the Rat Prelimbic Cortex and Dorsomedial Striatum Impairs Cue-Guided Behavioral Switching

ERIC Educational Resources Information Center

Baker, Phillip M.; Ragozzino, Michael E.

2014-01-01

Switches in reward outcomes or reward-predictive cues are two fundamental ways in which information is used to flexibly shift response patterns. The rat prelimbic cortex and dorsomedial striatum support behavioral flexibility based on a change in outcomes. The present experiments investigated whether these two brain regions are necessary for…

Accelerator Development for the NRL (Naval Research Laboratory) Free Electron Laser Program

DTIC Science & Technology

1988-06-01

reset CHARGE light 24 grey reset CHARGE light 26 purple reset gap pressure ON light . 27 blue RESET GAP PRESSURE switch 0 (bottom left) 28 red RESET...GAP PRESSURE switch (bottom middle) and chassis wire # 13 (red) 29 blue reset trigger FIRED light 30 orange reset gap pressure OFF light 31, orange ALL

Beam Switching of an Nd:YAG Laser Using Domain-Engineered Prisms in Magnesium-Oxide-Doped Congruent Lithium Niobate

DTIC Science & Technology

2010-08-01

In this work, a novel electro - optic beam switch (EOBS) is designed, fabricated and demonstrated. The EOBS presented in this work is designed for a...consists of a series of electronically controlled prisms fabricated by ferroelectric domain inversion in an electro - optic crystal wafer. The prisms are

Generalized Simulation Model for a Switched-Mode Power Supply Design Course Using MATLAB/SIMULINK

ERIC Educational Resources Information Center

Liao, Wei-Hsin; Wang, Shun-Chung; Liu, Yi-Hua

2012-01-01

Switched-mode power supplies (SMPS) are becoming an essential part of many electronic systems as the industry drives toward miniaturization and energy efficiency. However, practical SMPS design courses are seldom offered. In this paper, a generalized MATLAB/SIMULINK modeling technique is first presented. A proposed practical SMPS design course at…

Si:Bi switched photoconducttor infrared detector array

NASA Technical Reports Server (NTRS)

Eakin, C. E.

1983-01-01

A multiplexed infrared detector array is described. The small demonstration prototype consisted of two cryogenically cooled, bismuth doped silicon, extrinsic photoconductor pixels multiplexed onto a single output channel using an on focal plane switch integration sampling technique. Noise levels of the order of 400 to 600 rms electrons per sample were demonstrated for this chip and wire hybrid version.

Cycling firing method for bypass operation of bridge converters

DOEpatents

Zabar, Zivan

1982-01-01

The bridge converter comprises a number of switching elements and an electronic logic system which regulated the electric power levels by controlling the firing, i.e., the initiation of the conduction period of the switching elements. Cyclic firing of said elements allows the direct current to bypass the alternating current system with high power factor and negligible losses.

49 CFR Appendix A to Part 236 - Civil Penalties 1

Code of Federal Regulations, 2014 CFR

2014-10-01

... electro-magnetic, electronic, or electrical apparatus 1,000 2,000 236.9Selection of circuits through....4Interference with normal functioning of device 5,000 7,500 236.5Design of control circuits on closed circuit principle 1,000 2,000 236.6Hand-operated switch equipped with switch circuit controller 1,000 2,000 236...

49 CFR Appendix A to Part 236 - Civil Penalties 1

Code of Federal Regulations, 2013 CFR

2013-10-01

... electro-magnetic, electronic, or electrical apparatus 1,000 2,000 236.9Selection of circuits through....4Interference with normal functioning of device 5,000 7,500 236.5Design of control circuits on closed circuit principle 1,000 2,000 236.6Hand-operated switch equipped with switch circuit controller 1,000 2,000 236...

Power SEMICONDUCTORS—STATE of Art and Future Trends

NASA Astrophysics Data System (ADS)

Benda, Vitezslav

2011-06-01

The importance of effective energy conversion control, including power generation from renewable and environmentally clean energy sources, increases due to rising energy demand. Power electronic systems for controlling and converting electrical energy have become the workhorse of modern society in many applications, both in industry and at home. Power electronics plays a very important role in traction and can be considered as brawns of robotics and automated manufacturing systems. Power semiconductor devices are the key electronic components used in power electronic systems. Advances in power semiconductor technology have improved the efficiency, size, weight and cost of power electronic systems. At present, IGCTs, IGBTs, and MOSFETs represent modern switching devices. Power integrated circuits (PIC) have been developed for the use of power converters for portable, automotive and aerospace applications. For advanced applications, new materials (SiC and GaN) have been introduced. This paper reviews the state of these devices and elaborates on their potentials in terms of higher voltages, higher power density, and better switching performance.

Self-Reported Minimalist Running Injury Incidence and Severity: A Pilot Study.

PubMed

Ostermann, Katrina; Ridpath, Lance; Hanna, Jandy B

2016-08-01

Minimalist running entails using shoes with a flexible thin sole and is popular in the United States. Existing literature disagrees over whether minimalist running shoes (MRS) improve perceived severity of injuries associated with running in traditional running shoes (TRS). Additionally, the perceived injury patterns associated with MRS are relatively unknown. To examine whether injury incidence and severity (ie, degree of pain) by body region change after switching to MRS, and to determine if transition times affect injury incidences or severity with MRS. Runners who were either current or previous users of MRS were recruited to complete an Internet-based survey regarding self-reported injury before switching to MRS and whether self-reported pain from that injury decreased after switching. Questions regarding whether new injuries developed in respondents after switching to MRS were also included. Analyses were calculated using t tests, Wilcoxon signed rank tests, and Fischer exact tests. Forty-seven runners completed the survey, and 16 respondents reported injuries before switching to MRS. Among these respondents, pain resulting from injuries of the feet (P=.03) and knees (P=.01) decreased. Eighteen respondents (38.3%) indicated they sustained new injuries after switching to MRS, but the severity of these did not differ significantly from no injury. Neither time allowed for transition to MRS nor use or disuse of a stretching routine during this period was correlated with an increase in the incidence or severity of injuries. After switching to MRS, respondents perceived an improvement in foot and knee injuries. Additionally, respondents using MRS reported an injury rate of 38.3%, compared with the approximately 64% that the literature reports among TRS users. Future studies should be expanded to determine the full extent of the differences in injury patterns between MRS and TRS.

Organic photodetectors and their applications for hemispherical imaging focal plane arrays

NASA Astrophysics Data System (ADS)

Xu, Xin

Softness of organic semiconducting materials holds promise for fabricating optoelectronic devices and circuits on nonplanar surfaces. The low growth temperature of organic small molecules also allows for the deposition onto a plastic substrate, which has the potential for significantly lowering the fabrication cost. However, the softness of organic small molecules can become problematic. Most of the well-established patterning techniques in the semiconductor industry are not suitable for patterning organic-based devices. High temperatures, high pressures, exposure to wet chemicals or high-energy particles that may exist in the conventional patterning approaches can damage the organic active layers. Although methods for large area patterning of organic electronics onto planar substrates have been demonstrated, in this thesis we extend the patterning capability to curved surfaces by using a novel three dimensional (3D) cold welding method. We use 3D cold welding to fabricate a hemispherical focal plane array (FPA) for compact imaging systems that mimic the architecture and function of the human eye. A 10 kilopixel organic photodetector FPA is thus demonstrated on a 1 cm radius hemisphere. By patterning brittle yet transparent indium tin oxide anodes instead of semitransparent metal anodes on the hemispheres, the detectivity of the FPA is improved. We introduce a sensitive hybrid photodetector employing a carbon nanotube/small molecular organic junction with a broad spectral response extending into the near infrared. Since the photodetector array shows an increased noise level with the array size, integrated arrays of organic photodetectors and thin film transistors as switches are demonstrated.

Enhanced Thermo-Optical Switching of Paraffin-Wax Composite Spots under Laser Heating

PubMed Central

Said, Asmaa; Salah, Abeer; Abdel Fattah, Gamal

2017-01-01

Thermo-optical switches are of particular significance in communications networks where increasingly high switching speeds are required. Phase change materials (PCMs), in particular those based on paraffin wax, provide wealth of exciting applications with unusual thermally-induced switching properties, only limited by paraffin’s rather low thermal conductivity. In this paper, the use of different carbon fillers as thermal conductivity enhancers for paraffin has been investigated, and a novel structure based on spot of paraffin wax as a thermo-optic switch is presented. Thermo-optical switching parameters are enhanced with the addition of graphite and graphene, due to the extreme thermal conductivity of the carbon fillers. Differential Scanning Calorimetry (DSC) and Scanning electron microscope (SEM) are performed on paraffin wax composites, and specific heat capacities are calculated based on DSC measurements. Thermo-optical switching based on transmission is measured as a function of the host concentration under conventional electric heating and laser heating of paraffin-carbon fillers composites. Further enhancements in thermo-optical switching parameters are studied under Nd:YAG laser heating. This novel structure can be used in future networks with huge bandwidth requirements and electric noise free remote aerial laser switching applications. PMID:28772884

Enhanced Thermo-Optical Switching of Paraffin-Wax Composite Spots under Laser Heating.

PubMed

Said, Asmaa; Salah, Abeer; Fattah, Gamal Abdel

2017-05-12

Thermo-optical switches are of particular significance in communications networks where increasingly high switching speeds are required. Phase change materials (PCMs), in particular those based on paraffin wax, provide wealth of exciting applications with unusual thermally-induced switching properties, only limited by paraffin's rather low thermal conductivity. In this paper, the use of different carbon fillers as thermal conductivity enhancers for paraffin has been investigated, and a novel structure based on spot of paraffin wax as a thermo-optic switch is presented. Thermo-optical switching parameters are enhanced with the addition of graphite and graphene, due to the extreme thermal conductivity of the carbon fillers. Differential Scanning Calorimetry (DSC) and Scanning electron microscope (SEM) are performed on paraffin wax composites, and specific heat capacities are calculated based on DSC measurements. Thermo-optical switching based on transmission is measured as a function of the host concentration under conventional electric heating and laser heating of paraffin-carbon fillers composites. Further enhancements in thermo-optical switching parameters are studied under Nd:YAG laser heating. This novel structure can be used in future networks with huge bandwidth requirements and electric noise free remote aerial laser switching applications.

The concerted movement of the switch region of Troponin I in cardiac muscle thin filaments as tracked by conventional and pulsed (DEER) EPR.

PubMed

Potluri, Phani R; Chamoun, Jean; Cooke, James A; Badr, Myriam; Guse, Joanna A; Rayes, Roni; Cordina, Nicole M; McCamey, Dane; Fajer, Piotr G; Brown, Louise J

2017-12-01

The absence of a crystal structure of the calcium free state of the cardiac isoform of the troponin complex has hindered our understanding of how the simple binding of Ca 2+ triggers conformational changes in troponin which are then propagated to enable muscle contraction. Here we have used continuous wave (CW) and Double Electron-Electron Resonance (DEER) pulsed EPR spectroscopy to measure distances between TnI and TnC to track the movement of the functionally important regulatory 'switch' region of cardiac Tn. Spin labels were placed on the switch region of Troponin I and distances measured to Troponin C. Under conditions of high Ca 2+ , the interspin distances for one set (TnI151/TnC84) were 'short' (9-10Å) with narrow distance distribution widths (3-8Å) indicating the close interaction of the switch region with the N-lobe of TnC. Additional spin populations representative of longer interspin distances were detected by DEER. These longer distance populations, which were ∼16-19Å longer than the short distance populations, possessed notably broader distance distribution widths (14-29Å). Upon Ca 2+ removal, the interspin population shifted toward the longer distances, indicating the release of the switch region from TnC and an overall increase in disorder for this region. Together, our results suggest that under conditions of low Ca 2+ , the close proximity of the TnI switch region to TnC in the cardiac isoform is necessary for promoting the interaction between the regulatory switch helix with the N-lobe of cardiac Troponin C, which, unlike the skeletal isoform, is largely in a closed conformation. Copyright © 2017 Elsevier Inc. All rights reserved.

Negative voltage modulated multi-level resistive switching by using a Cr/BaTiOx/TiN structure and quantum conductance through evidence of H2O2 sensing mechanism.

PubMed

Chakrabarti, Somsubhra; Ginnaram, Sreekanth; Jana, Surajit; Wu, Zong-Yi; Singh, Kanishk; Roy, Anisha; Kumar, Pankaj; Maikap, Siddheswar; Qiu, Jian-Tai; Cheng, Hsin-Ming; Tsai, Ling-Na; Chang, Ya-Ling; Mahapatra, Rajat; Yang, Jer-Ren

2017-07-05

Negative voltage modulated multi-level resistive switching with quantum conductance during staircase-type RESET and its transport characteristics in Cr/BaTiO x /TiN structure have been investigated for the first time. The as-deposited amorphous BaTiO x film has been confirmed by high-resolution transmission electron microscopy. X-ray photo-electron spectroscopy shows different oxidation states of Ba in the switching material, which is responsible for tunable more than 10 resistance states by varying negative stop voltage owing to slow decay value of RESET slope (217.39 mV/decade). Quantum conductance phenomenon has been observed in staircase RESET cycle of the memory devices. By inspecting the oxidation states of Ba + and Ba 2+ through measuring H 2 O 2 with a low concentration of 1 nM in electrolyte/BaTiO x /SiO 2 /p-Si structure, the switching mechanism of each HRS level as well as the multi-level phenomenon has been explained by gradual dissolution of oxygen vacancy filament. Along with negative stop voltage modulated multi-level, current compliance dependent multi-level has also been demonstrated and resistance ratio up to 2000 has been achieved even for a thin (<5 nm) switching material. By considering oxidation-reduction of the conducting filaments, the current-voltage switching curve has been simulated as well. Hence, multi-level resistive switching of Cr/BaTiO x /TiN structure implies the promising applications in high dense, multistate non-volatile memories in near future.

Resistive switching mechanisms in random access memory devices incorporating transition metal oxides: TiO2, NiO and Pr0.7Ca0.3MnO3.

PubMed

Magyari-Köpe, Blanka; Tendulkar, Mihir; Park, Seong-Geon; Lee, Hyung Dong; Nishi, Yoshio

2011-06-24

Resistance change random access memory (RRAM) cells, typically built as MIM capacitor structures, consist of insulating layers I sandwiched between metal layers M, where the insulator performs the resistance switching operation. These devices can be electrically switched between two or more stable resistance states at a speed of nanoseconds, with long retention times, high switching endurance, low read voltage, and large switching windows. They are attractive candidates for next-generation non-volatile memory, particularly as a flash successor, as the material properties can be scaled to the nanometer regime. Several resistance switching models have been suggested so far for transition metal oxide based devices, such as charge trapping, conductive filament formation, Schottky barrier modulation, and electrochemical migration of point defects. The underlying fundamental principles of the switching mechanism still lack a detailed understanding, i.e. how to control and modulate the electrical characteristics of devices incorporating defects and impurities, such as oxygen vacancies, metal interstitials, hydrogen, and other metallic atoms acting as dopants. In this paper, state of the art ab initio theoretical methods are employed to understand the effects that filamentary types of stable oxygen vacancy configurations in TiO(2) and NiO have on the electronic conduction. It is shown that strong electronic interactions between metal ions adjacent to oxygen vacancy sites results in the formation of a conductive path and thus can explain the 'ON' site conduction in these materials. Implication of hydrogen doping on electroforming is discussed for Pr(0.7)Ca(0.3)MnO(3) devices based on electrical characterization and FTIR measurements.

Preparation of Iridescent 2D Photonic Crystals by Using a Mussel-Inspired Spatial Patterning of ZIF-8 with Potential Applications in Optical Switch and Chemical Sensor.

PubMed

Razmjou, Amir; Asadnia, Mohsen; Ghaebi, Omid; Yang, Hao-Cheng; Ebrahimi Warkiani, Majid; Hou, Jingwei; Chen, Vicki

2017-11-01

In this work, spatial patterning of a thin, dense, zeolitic imidazolate framework (ZIF-8) pattern was generated using photolithography and nanoscale (60 nm) dopamine coating. A bioinspired, unique, reversible, two-color iridescent pattern can be easily obtained for potential applications in sensing and photonics.

Ultralow-voltage design of graphene PN junction quantum reflective switch transistor

NASA Astrophysics Data System (ADS)

Sohier, Thibault; Yu, Bin

2011-05-01

We propose the concept of a graphene-based quantum reflective switch (QRS) for low-power logic application. With the unique electronic properties of graphene, a tilted PN junction is used to implement logic switch function with 103 ON/OFF ratio. Carriers are reflected on an electrostatically induced potential step with strong incidence-angle-dependency due to the widening of classically forbidden energies. Optimized design of the device for ultralow-voltage operating has been conducted. The device is constantly ON with a turning-off gate voltage around 180 mV using thin HfO2 as the gate dielectric. The results suggest a class of logic switch devices operating with micropower dissipation.

Amplitude steered array

NASA Technical Reports Server (NTRS)

Dietrich, F. J.; Koloboff, G. J.; Martel, R. J.; Johnson, C. C. (Inventor)

1974-01-01

A spin stabilized satellite has an electronically despun antenna array comprising a multiplicity of peripheral antenna elements. A high gain energy beam is established by connecting a suitable fraction or array of the elements in phase. The beam is steered or caused to scan by switching elements in sequence into one end of the array as elements at the other end of the array are switched out. The switching transients normally associated with such steering are avoided by an amplitude control system. Instead of abruptly switching from one element to the next, a fixed value of power is gradually transferred from the element at the trailing edge of the array to the element next to the leading edge.

Emergency Physician Task Switching Increases With the Introduction of a Commercial Electronic Health Record.

PubMed

Benda, Natalie C; Meadors, Margaret L; Hettinger, A Zachary; Ratwani, Raj M

2016-06-01

We evaluate how the transition from a homegrown electronic health record to a commercial one affects emergency physician work activities from initial introduction to long-term use. We completed a quasi-experimental study across 3 periods during the transition from a homegrown system to a commercially available electronic health record with computerized provider order entry. Observation periods consisted of pre-implementation, 1 month before the implementation of the commercial electronic health record; "go-live" 1 week after implementation; and post-implementation, 3 to 4 months after use began. Fourteen physicians were observed in each period (N=42) with a minute-by-minute observation template to record emergency physician time allocation across 5 task-based categories (computer, verbal communication, patient room, paper [chart/laboratory results], and other). The average number of tasks physicians engaged in per minute was also analyzed as an indicator of task switching. From pre- to post-implementation, there were no significant differences in the amount of time spent on the various task categories. There were changes in time allocation from pre-implementation to go-live and go-live to pre-implementation, characterized by a significant increase in time spent on computer tasks during go-live relative to the other periods. Critically, the number of tasks physicians engaged in per minute increased from 1.7 during pre-implementation to 1.9 during post-implementation (difference 0.19 tasks per minute; 95% confidence interval 0.039 to 0.35). The increase in the number of tasks physicians engaged in per minute post-implementation indicates that physicians switched tasks more frequently. Frequent task switching behavior raises patient safety concerns. Copyright © 2015 American College of Emergency Physicians. Published by Elsevier Inc. All rights reserved.

Aspects of Dzyaloshinskii-Moriya Interaction in Two Dimensional Magnetic Structures

NASA Astrophysics Data System (ADS)

Kundu, Anirban

Research on topologically protected chiral magnetic structures such as magnetic domain walls (DWs) and skyrmions, have gained extensive interest because of their possible applications in magnetic data storage industries. The recently observed chiral DW structures in ultrathin ferromagnetic lms with perpendicular magnetic anisotropy has been attributed to the presence of a strong Dzyaloshinskii-Moriya interaction (DMI). In this thesis, the DMI mediated by the conduction electrons in two dimensional magnetic systems such as magnetic thin lms or at the interfaces between two magnetic materials has been studied. I calculate the Ruderman-Kittel- Kasuya-Yosida (RKKY) type indirect exchange coupling between two magnetic moments at nite temperature using the free electron band. At high temperature, the coupling strength decays with distance faster than the coupling at zero temperature but the period of oscillation remains same. However, the free electron band alone could not produce DMI. In the next step, I show addition of Rashba spin-orbit coupling (RSOC) with the spin-polarized conduction electron band produces the DMI between two magnetic ions. The essential feature of this DMI is: the coupling strength increases with the strength of RSOC, but decreases signi cantly with the Heisenberg exchange coupling. The DMI calculated with this model well explains the possibility of preferred Neel or Bloch DW structures with specifc chirality. In addition: I study switching of magnetization with ultrafast laser pulse by inverse Faraday e ect (IFE) where an optically induced non-equilibrium orbital momentum generates an e ective magnetic eld via spin-orbit coupling for magnetization switching. I calculate the magnitude of induced orbital moment for the generic itinerant band and show that magnitude is not large enough to make the switching by a single pulse, however, switching could be possible if multiple pulses are applied to the material.

Investigation of resistive switching behaviours in WO3-based RRAM devices

NASA Astrophysics Data System (ADS)

Li, Ying-Tao; Long, Shi-Bing; Lü, Hang-Bing; Liu, Qi; Wang, Qin; Wang, Yan; Zhang, Sen; Lian, Wen-Tai; Liu, Su; Liu, Ming

2011-01-01

In this paper, a WO3-based resistive random access memory device composed of a thin film of WO3 sandwiched between a copper top and a platinum bottom electrodes is fabricated by electron beam evaporation at room temperature. The reproducible resistive switching, low power consumption, multilevel storage possibility, and good data retention characteristics demonstrate that the Cu/WO3/Pt memory device is very promising for future nonvolatile memory applications. The formation and rupture of localised conductive filaments is suggested to be responsible for the observed resistive switching behaviours.

High voltage switch triggered by a laser-photocathode subsystem

DOEpatents

Chen, Ping; Lundquist, Martin L.; Yu, David U. L.

2013-01-08

A spark gap switch for controlling the output of a high voltage pulse from a high voltage source, for example, a capacitor bank or a pulse forming network, to an external load such as a high gradient electron gun, laser, pulsed power accelerator or wide band radar. The combination of a UV laser and a high vacuum quartz cell, in which a photocathode and an anode are installed, is utilized as triggering devices to switch the spark gap from a non-conducting state to a conducting state with low delay and low jitter.

Progress on complementary patterning using plasmon-excited electron beamlets (Conference Presentation)

NASA Astrophysics Data System (ADS)

Du, Zhidong; Chen, Chen; Pan, Liang

2017-04-01

Maskless lithography using parallel electron beamlets is a promising solution for next generation scalable maskless nanolithography. Researchers have focused on this goal but have been unable to find a robust technology to generate and control high-quality electron beamlets with satisfactory brightness and uniformity. In this work, we will aim to address this challenge by developing a revolutionary surface-plasmon-enhanced-photoemission (SPEP) technology to generate massively-parallel electron beamlets for maskless nanolithography. The new technology is built upon our recent breakthroughs in plasmonic lenses, which will be used to excite and focus surface plasmons to generate massively-parallel electron beamlets through photoemission. Specifically, the proposed SPEP device consists of an array of plasmonic lens and electrostatic micro-lens pairs, each pair independently producing an electron beamlet. During lithography, a spatial optical modulator will dynamically project light onto individual plasmonic lenses to control the switching and brightness of electron beamlets. The photons incident onto each plasmonic lens are concentrated into a diffraction-unlimited spot as localized surface plasmons to excite the local electrons to near their vacuum levels. Meanwhile, the electrostatic micro-lens extracts the excited electrons to form a focused beamlet, which can be rastered across a wafer to perform lithography. Studies showed that surface plasmons can enhance the photoemission by orders of magnitudes. This SPEP technology can scale up the maskless lithography process to write at wafers per hour. In this talk, we will report the mechanism of the strong electron-photon couplings and the locally enhanced photoexcitation, design of a SPEP device, overview of our proof-of-concept study, and demonstrated parallel lithography of 20-50 nm features.

A multi-stimuli responsive switch as a fluorescent molecular analogue of transistors† †Electronic supplementary information (ESI) available: Detailed experimental procedures and additional data on the characterization of 1. See DOI: 10.1039/c5sc03395k Click here for additional data file.

PubMed Central

Gallardo, Iluminada; Morais, Sandy; Prats, Gemma

2016-01-01

Although the quantum nature of molecules makes them specially suitable for mimicking the operation of digital electronic elements, molecular compounds can also be envisioned to emulate the behavior of analog devices. In this work we report a novel fluorescent three-state switch capable of reproducing the analog response of transistors, an ubiquitous device in modern electronics. Exploiting the redox and thermal sensitivity of this compound, the amplitude of its fluorescence emission can be continuously modulated, in a similar way as the output current in a transistor is amplified by the gate-to-source voltage. PMID:28959394

Free Language Selection in the Bilingual Brain: An Event-Related fMRI Study

PubMed Central

Zhang, Yong; Wang, Tao; Huang, Peiyu; Li, Dan; Qiu, Jiang; Shen, Tong; Xie, Peng

2015-01-01

Bilingual speakers may select between two languages either on demand (forced language selection) or on their own volition (free language selection). However, the neural substrates underlying free and forced language selection may differ. While the neural substrates underlying forced language selection have been well-explored with language switching paradigms, those underlying free language selection have remained unclear. Using a modified digit-naming switching paradigm, we addressed the neural substrates underlying free language selection by contrasting free language switching with forced language switching. For a digit-pair trial, Chinese-English bilinguals named each digit in Chinese or English either on demand under forced language selection condition or on their own volition under free language selection condition. The results revealed activation in the frontoparietal regions that mediate volition of language selection. Furthermore, a comparison of free and forced language switching demonstrated differences in the patterns of brain activation. Additionally, free language switching showed reduced switching costs as compared to forced language switching. These findings suggest differences between the mechanism(s) underlying free and forced language switching. As such, the current study suggests interactivity between control of volition and control of language switching in free language selection, providing insights into a model of bilingual language control. PMID:26177885

Microsecond reconfigurable NxN data-communication switch using DMD

NASA Astrophysics Data System (ADS)

Blanche, Pierre-Alexandre; Miles, Alexander; Lynn, Brittany; Wissinger, John; Carothers, Daniel; Norwood, Robert A.; Peyghambarian, Nasser

2014-03-01

We present here the use the DMD as a diffraction-based optical switch, where Fourier diffraction patterns are used to steer the incoming beams to any output configuration. We have implemented a single-mode fiber coupled N X N switch and demonstrated its ability to operate over the entire telecommunication C-band centered at 1550 nm. The all-optical switch was built primarily with off-the-shelf components and a Texas Instruments DLP7000™with an array of 1024 X 768 micromirrors. This DMD is capable of switching 100 times faster than currently available technology (3D MOEMS). The switch is robust to typical failure modes, protocol and bit-rate agnostic, and permits full reconfigurable optical add drop multiplexing (ROADM). The switch demonstrator was inserted into a networking testbed for the majority of the measurements. The testbed assembled under the Center for Integrated Access Networks (ClAN), a National Science Foundation (NSF) Engineering Research Center (ERC), provided an environment in which to simulate and test the data routing functionality of the switch. A Fujitsu Flashwave 9500 PS was used to provide the data signal, which was sent through the switch and received by a second Flashwave node. We successfully transmitted an HD video stream through a switched channel without any measurable data loss.

Multimodal Responses of Self-Organized Circuitry in Electronically Phase Separated Materials

DOE PAGES

Herklotz, Andreas; Guo, Hangwen; Wong, Anthony T.; ...

2016-07-13

When confining an electronically phase we separated manganite film to the scale of its coexisting self-organized metallic and these insulating domains allows resistor-capacitor circuit-like responses while providing both electroresistive and magnetoresistive switching functionality.

Electronic circuit provides accurate sensing and control of dc voltage

NASA Technical Reports Server (NTRS)

Loftus, W. D.

1966-01-01

Electronic circuit used relay coil to sense and control dc voltage. The control relay is driven by a switching transistor that is biased to cutoff for all input up to slightly less than the threshold level.