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1

Operation of Bidirectional Switches (DIAC) and Silicon Controlled Rectifiers (SCR) in Gamma-Radiation Environment  

SciTech Connect

Gamma-irradiation effects on the electrical parameters of the Diode AC switch (DIAC; PHI37 500) and Silicon Controlled Rectifier (SCR; 2N4444) devices have been studied in detail, where gamma-dose up to 137 x 106 rad was found to cause a serious permanent damage on their electrical characteristics. A pronounced increase in the break-over voltage (from 31.5 to 35 V), holding-current (from 13 to 53 mA) and holding voltage (from 22 to 32 V) of the DIAC is noticed. Besides, a severe decrease in the dynamic break-over voltage range (from 10 to 2.5 V) and negative resistance (from -750 to -168 ohm) is also observed. Exposing the SCRs to gamma-radiation causes their turn-on voltage and forward voltage drop values to increase from 0.8 to 2.8 V and from 1.4 to 4.5 V, respectively. Additionally, the holding current increases to 18 mA although its initial value is 3.5 mA. For the two devices, the linear dependence and high sensitivity of their electrical parameters to gamma-dose suggest the application of such devices in the field of radiation dosimetry.

Swidan, A.M.; El-Ghanam, S.M. [Women's College for Art, Science and Education, Ain- Shams University, Helioplis, Cairo (Egypt); Soliman, F.A.S. [Nuclear Materials Authority, P.O. Box 2404, Horrya-11361, Heliopolis, Cairo (Egypt)

2005-03-17

2

Road load simulator tests of the Gould phase 1 functional model silicon controlled rectifier ac motor controller for electric vehicles  

NASA Technical Reports Server (NTRS)

The test results for a functional model ac motor controller for electric vehicles and a three-phase induction motor which were dynamically tested on the Lewis Research Center road load simulator are presented. Results show that the controller has the capability to meet the SAE-J227a D cycle test schedule and to accelerate a 1576-kg (3456-lb) simulated vehicle to a cruise speed of 88.5 km/hr (55 mph). Combined motor controller efficiency is 72 percent and the power inverter efficiency alone is 89 percent for the cruise region of the D cycle. Steady state test results for motoring, regeneration, and thermal data obtained by operating the simulator as a conventional dynamometer are in agreement with the contractor's previously reported data. The regeneration test results indicate that a reduction in energy requirements for urban driving cycles is attainable with regenerative braking. Test results and data in this report serve as a data base for further development of ac motor controllers and propulsion systems for electric vehicles. The controller uses state-of-the-art silicon controlled rectifier (SCR) power semiconductors and microprocessor-based logic and control circuitry. The controller was developed by Gould Laboratories under a Lewis contract for the Department of Energy's Electric and Hybrid Vehicle program.

Gourash, F.

1984-01-01

3

Road load simulator tests of the Gould phase 1 functional model silicon controlled rectifier ac motor controller for electric vehicles  

NASA Astrophysics Data System (ADS)

The test results for a functional model ac motor controller for electric vehicles and a three-phase induction motor which were dynamically tested on the Lewis Research Center road load simulator are presented. Results show that the controller has the capability to meet the SAE-J227a D cycle test schedule and to accelerate a 1576-kg (3456-lb) simulated vehicle to a cruise speed of 88.5 km/hr (55 mph). Combined motor controller efficiency is 72 percent and the power inverter efficiency alone is 89 percent for the cruise region of the D cycle. Steady state test results for motoring, regeneration, and thermal data obtained by operating the simulator as a conventional dynamometer are in agreement with the contractor's previously reported data. The regeneration test results indicate that a reduction in energy requirements for urban driving cycles is attainable with regenerative braking. Test results and data in this report serve as a data base for further development of ac motor controllers and propulsion systems for electric vehicles. The controller uses state-of-the-art silicon controlled rectifier (SCR) power semiconductors and microprocessor-based logic and control circuitry. The controller was developed by Gould Laboratories under a Lewis contract for the Department of Energy's Electric and Hybrid Vehicle program.

Gourash, F.

1984-02-01

4

Molecular rectifying diodes from self-assembly on silicon  

E-print Network

Molecular rectifying diodes from self-assembly on silicon Stéphane Lenfant , Christophe Krzeminski a molecular rectifying junction made from a sequential self-assembly on silicon. The device structure consists calculations and internal photoemission spectroscopy. This approach allows us to fabricate molecular rectifying

Paris-Sud XI, Université de

5

Silicon Carbide High-Temperature Power Rectifiers Fabricated and Characterized  

NASA Technical Reports Server (NTRS)

The High Temperature Integrated Electronics and Sensors (HTIES) team at the NASA Lewis Research Center is developing silicon carbide (SiC) for use in harsh conditions where silicon, the semiconductor used in nearly all of today's electronics, cannot function. Silicon carbide's demonstrated ability to function under extreme high-temperature, high power, and/or high-radiation conditions will enable significant improvements to a far ranging variety of applications and systems. These improvements range from improved high-voltage switching for energy savings in public electric power distribution and electric vehicles, to more powerful microwave electronics for radar and cellular communications, to sensors and controls for cleaner-burning, more fuel-efficient jet aircraft and automobile engines. In the case of jet engines, uncooled operation of 300 to 600 C SiC power actuator electronics mounted in key high-temperature areas would greatly enhance system performance and reliability. Because silicon cannot function at these elevated temperatures, the semiconductor device circuit components must be made of SiC. Lewis' HTIES group recently fabricated and characterized high-temperature SiC rectifier diodes whose record-breaking characteristics represent significant progress toward the realization of advanced high-temperature actuator control circuits. The first figure illustrates the 600 C probe-testing of a Lewis SiC pn-junction rectifier diode sitting on top of a glowing red-hot heating element. The second figure shows the current-versus voltage rectifying characteristics recorded at 600 C. At this high temperature, the diodes were able to "turn-on" to conduct 4 A of current when forward biased, and yet block the flow of current ($quot;turn-off") when reverse biases as high as 150 V were applied. This device represents a new record for semiconductor device operation, in that no previous semiconductor electronic device has ever simultaneously demonstrated 600 C functionality, and 4-A turn-on and 150-V rectification. The high operating current was achieved despite severe device size limitations imposed by present-day SiC wafer defect densities. Further substantial increases in device performance can be expected when SiC wafer defect densities decrease as SiC wafer production technology matures.

1996-01-01

6

PWM Control Techniques for Rectifier Filter Minimization  

Microsoft Academic Search

Minimization of input\\/output filters is an essential step towards manufacturing compact low-cost static power supplies. Three PWM control techniques that yield substantial filter size reduction for three-phase (self-commutated) rectifiers are presented and analyzed. Filters required by typical line-commutated rectifiers are used as the basis for comparison. Moreover, it is shown that in addition to filter minimization two of the proposed

Phoivas D. Ziogas; Young-Goo Kang; Victor R. Stefanovic

1985-01-01

7

Sensorless control strategies for PWM rectifier  

Microsoft Academic Search

In this paper two different control strategies for a PWM rectifier without line voltage sensors are compared. The direct power control (DPC) which has no need for line voltage measurements is compared to the conventional voltage oriented control (VOC) strategy in rotating coordinates with a novel line voltage estimator. The steady-state performance of both strategies is compared with regards to

Steffan Hansen; Mariusz Malinowski; Frede Blaabjerg; Marian P. Kazmierkowski

2000-01-01

8

Reference frames fit for controlling PWM rectifiers  

Microsoft Academic Search

The authors argue that one should keep things simple when controlling bidirectional pulsewidth modulation rectifiers by considering the utility grid as a virtual electric machine. The advantage is that the air-gap flux of this big machine can be directly measured in a straightforward way. Therefore, as shown in this paper, principles of field orientation can be applied to control the

J. L. Duarte; A. Van Zwam; CGE Wijnands; A. Vandenput

1999-01-01

9

A 50KVA Adjustable-Frequency 24Phase Controlled Rectifier Inverter  

Microsoft Academic Search

This paper describes a multiphase 50-kva silicon-controlled rectifier inverter that uses phase displacement of the outputs from four 3-phase bridge inverters to generate a 3-phase output waveform with low harmonic content. The output voltage is controlled over a wide range by simply changing the phase position of controlled rectifier gate signals. Low harmonic content is maintained in the unfiltered output

C. W. Flairty

1962-01-01

10

Observer Based Control for a Single Phase Active Rectifier  

Microsoft Academic Search

There are two control objectives in active rectifiers: DC regulation and power factor correction, however it is difficult to reach both objectives simultaneously. In this paper is presented the use of an observer based control for complete both control objectives. A proporcional integral (PI) control is applied to regulate DC voltage and a hysteresis based control for improve the power

M. Flota; R. Alvarez; C. Nunez

2007-01-01

11

Simplified control of a three-phase PWM rectifier  

Microsoft Academic Search

A simple algorithm to control the PWM rectifier has been presented. Harmonics and unbalance in the AC-side line currents are compensated and the DC-bus voltage is regulated. The power factor of the compensated line currents is high. The algorithm may be used unmodified to control an active power filter. Simulation and experimental results have been presented to validate the control

S. R. Naidu; D. A. Fernandes; K. P. Medeiros

2011-01-01

12

Analysis, Design and Control of 1MW, High Power Factor and High Current Rectifier System  

E-print Network

Analysis, Design and Control of 1MW, High Power Factor and High Current Rectifier System Jitendra-Belecke, Germany peter.wallmeier@aegps.com Abstract-- This paper presents a 1MW, 12-pulse thyristor rectifier topologies for rectification. Six switch PWM voltage source rectifier and PWM current source rectifier

Paderborn, Universität

13

Power system controller in an intelligent telecom rectifier plant  

Microsoft Academic Search

An intelligent power system controller (PSC) philosophy and concept for intelligent rectifier plants are presented. A modular, flexible control system is an ideal platform built for all necessary functions to fulfill all the requirements and the needs of owners, users, and operators of telecom plants. Changes or additions of functions are implemented only by software. High availability can be achieved

Ueli Roth

1992-01-01

14

Development of PI controller for battery charger using PFC rectifier  

Microsoft Academic Search

This paper illustrated simulation evaluations of a PI Controller for battery Charger employing Power Factor Correction (PFC) rectifier using MATLAB Simulink software packages and was compared with hardware prototype. The proposed system has been used single-phase incorporated with proportional-integral control technique to give appropriate compensation to resolve problems caused by the load such as current displacement, current harmonics and to

M. N. M. Hussain; M. F. M. Idris; I. Intan Rahayu; K. H. Mustafar; D. Nor Salwa; O. Nor Azlan; R. Rosfariza

2010-01-01

15

BitStream control of three phase reversible rectifiers  

Microsoft Academic Search

Bit-stream is a new technique for controlling power electronics applications by interconnecting appropriate control elements inside an FPGA. This paper presents a Bit-Stream based controller for a three phase, 400 V \\/ 7 kVA reversible rectifier, which is used to transfer power between an AC line and a DC bus in a controlled manner. The proposed controller is based on

Jonathan Bradshaw; Udaya Madawala; Nitish Patel

2009-01-01

16

This material may be nrr,tQ,,,t,, Digitally Controlled Low-Harmonic Rectifier  

E-print Network

This material may be nrr,tQ,,,t,, Digitally Controlled Low-Harmonic Rectifier Having Fast Dynamic digitally controlled low-harmonic rectifier. It is shown that the dynamics of the outer voltage loop can and efficient method for implementation of a digital controller for a PFC (power factor correct) rectifier

Prodiæ, Aleksandar

17

A single-phase controlled-current PWM rectifier  

Microsoft Academic Search

The analysis and test results are given for an experimental single-phase controlled-current PWM (pulse-width-modulated) rectifier that operates at unity power factor with near sinusoidal current waveform and that has power reversal capability. The twice-line-frequency AC power is identified as a source of voltage harmonics in the DC link. The harmonics enter into the voltage regulation feedback loop to distort the

O. Stihi; Boon-Teck Ooi

1988-01-01

18

Design, fabrication, and characterization of 4H-silicon carbide rectifiers for power switching applications  

NASA Astrophysics Data System (ADS)

Silicon Carbide has received a substantial increase in research interest over the past few years as a base material system for high-frequency and high-power semiconductor devices. Of the over 1200 polytypes, 4H-SiC is the most attractive polytype for power devices due to its wide band gap (3.2eV), excellent thermal conductivity (4.9 W/cmK), and high critical field strength (2 x 106 V/cm). Important for power devices, the 10x increase in critical field strength of SiC allows high voltage blocking layers to be fabricated significantly thinner than for comparable Si devices. For power rectifiers, this reduces device on-resistance, while maintaining the same high voltage blocking capability. In this work, 4H-SiC Schottky, pn, and junction barrier Schottky (JBS) rectifiers for use in high voltage switching applications have been designed, fabricated, and extensively characterized. First, a detailed review of 4H-SiC material parameters was performed and SiC models were implemented into a standard Si drift-diffusion numerical simulator. Using these models, a SiC simulation methodology was developed in order to enable predictive SiC device design. A wide variety of rectifier and edge termination designs were investigated and optimized with respect to breakdown efficiency, area consumption, resistance to interface charge, and fabrication practicality. Simulated termination methods include: field plates, floating guard rings, and a variety of junction termination extensions (JTE). Using the device simulation results, both Schottky and JBS rectifiers were fabricated with a novel self-aligned edge termination design, and fabricated with process elements developed at the Alabama Microelectronics Science and Technology Center facility. These rectifiers exhibited near-ideal forward characteristics and had blocking voltages in excess of 2.5kV. The SiC diodes were subjected to inductive switching tests, and were found to have superior reverse recovery characteristics compared to a similar Si diode. Finally, the performance of these SiC rectifiers were tested in inductive switching circuits and in high dose gamma radiation environments. In both cases, these devices were shown to be superior to their silicon counterparts. The details of this work was presented and published in the proceedings of the 45th International Meeting of the American Vacuum Society [1], the 1999 International Conference on Silicon Carbide and Related Materials [2, 3] and the 2000 European Conference on Silicon Carbide and Related Materials [4]. The expanded conference papers were published in the international journal. Solid-State Electronics [5, 6].

Sheridan, David Charles

19

Temperature-gated thermal rectifier for active heat flow control.  

PubMed

Active heat flow control is essential for broad applications of heating, cooling, and energy conversion. Like electronic devices developed for the control of electric power, it is very desirable to develop advanced all-thermal solid-state devices that actively control heat flow without consuming other forms of energy. Here we demonstrate temperature-gated thermal rectification using vanadium dioxide beams in which the environmental temperature actively modulates asymmetric heat flow. In this three terminal device, there are two switchable states, which can be regulated by global heating. In the "Rectifier" state, we observe up to 28% thermal rectification. In the "Resistor" state, the thermal rectification is significantly suppressed (<1%). To the best of our knowledge, this is the first demonstration of solid-state active-thermal devices with a large rectification in the Rectifier state. This temperature-gated rectifier can have substantial implications ranging from autonomous thermal management of heating and cooling systems to efficient thermal energy conversion and storage. PMID:25010206

Zhu, Jia; Hippalgaonkar, Kedar; Shen, Sheng; Wang, Kevin; Abate, Yohannes; Lee, Sangwook; Wu, Junqiao; Yin, Xiaobo; Majumdar, Arun; Zhang, Xiang

2014-08-13

20

Temperature-Gated Thermal Rectifier for Active Heat Flow Control Kedar Hippalgaonkar,,  

E-print Network

Temperature-Gated Thermal Rectifier for Active Heat Flow Control Jia Zhu,, Kedar Hippalgaonkar. In the "Rectifier" state, we observe up to 28% thermal rectification. In the "Resistor" state, the thermal of solid-state active-thermal devices with a large rectification in the Rectifier state. This temperature

Wu, Junqiao

21

Characteristics of a Controlled-Current PWM Rectifier-Inverter Link  

Microsoft Academic Search

Two controlled-current pulsewidth-modulated (PWM) converters have been integrated into rectifier-inverter links of variable-speed ac motor drives. The authors focus on developing a mathematical model of the rectifier-inverter link and presenting experimental justification of the model. The characteristics of the rectifier-inverter system and the constraints imposed by the voltage feedback loop and dc link voltage are discussed. The rectifier-inverter system is

Juan W. Dixon; Ashok B. Kulkarni; Masahiro Nishimoto; Boon-Teck Ooi

1987-01-01

22

Modelling a single phase voltage controlled rectifier using Laplace transforms  

NASA Technical Reports Server (NTRS)

The development of a 20 kHz, AC power system by NASA for large space projects has spurred a need to develop models for the equipment which will be used on these single phase systems. To date, models for the AC source (i.e., inverters) have been developed. It is the intent of this paper to develop a method to model the single phase voltage controlled rectifiers which will be attached to the AC power grid as an interface for connected loads. A modified version of EPRI's HARMFLO program is used as the shell for these models. The results obtained from the model developed in this paper are quite adequate for the analysis of problems such as voltage resonance. The unique technique presented in this paper uses the Laplace transforms to determine the harmonic content of the load current of the rectifier rather than a curve fitting technique. Laplace transforms yield the coefficient of the differential equations which model the line current to the rectifier directly.

Kraft, L. Alan; Kankam, M. David

1992-01-01

23

Abstract--A control structure for an interleaved power factor correction (PFC) rectifier with smart combination of analog and  

E-print Network

Abstract-- A control structure for an interleaved power factor correction (PFC) rectifier-digital control approach is verified by experimental results. Keywords: power factor correction rectifier, digital correction (PFC) rectifier is widely used as front-end stage for AC-DC switched-mode power supplies (SMPS

Paderborn, Universität

24

MODELING AND VALIDATION OF A SYNCHRONOUS-MACHINE/CONTROLLED-RECTIFIER SYSTEM.  

E-print Network

??The hardware validation of a novel average-value model (AVM) for the simulation of a synchronous-generator/controlled rectifier system is presented herein. The generator is characterized using (more)

Hord, Kyle A

2014-01-01

25

Minimization of DC Reactor and Operation Characteristics of Direct-Power-Controlled Current-Source PWM Rectifier  

E-print Network

-Source PWM Rectifier Toshihiko Noguchi, Akira Sato, and Daisuke Takeuchi Nagaoka University of Technology describes a direct-power-controlled current-source PWM rectifier, and presents operation characteristics. In order to achieve this goal, a PWM rectifier is widely used in variety of industry applications, which

Fujimoto, Hiroshi

26

State variable decoupling and power flow control in PWM current-source rectifiers  

Microsoft Academic Search

Pulsewidth modulated (PWM) current-source rectifiers (CSR), among other alternatives, offer marked improvements over thyristor line-commutated rectifiers as a source of variable DC power. Advantages include reduced line current harmonic distortion and complete displacement power factor control, including unity displacement power factor operation. However, due to nonlinearities of the PWM-CSR model, their control has usually been carried out using direct line

Jose R. Espinoza; Geza Joos

1998-01-01

27

A vector controlled current-source PWM rectifier with a novel current damping method  

Microsoft Academic Search

Three-phase current-type pulse width modulation (PWM) rectifiers are becoming increasingly popular as the front-end converter unit in power electronic systems due to tighter electromagnetic compatibility (EMC) regulations. In this paper the control of the current source PWM rectifier in the synchronously rotating reference frame is discussed. A control system is presented in which the active and reactive power are independently

Mika Salo; Heikki Tuusa

2000-01-01

28

An Integrated Controlled-Current PWM Rectifier Chopper Link for Sliding Mode Position Control  

Microsoft Academic Search

Position controllers must handle kinetic energy exchanges during acceleration and deceleration of large inertias. Temporary buffer storage in capacitors is expensive. The system that can manage the power exchange with ease is the integrated controlled-current pulsewidth-modulated (PWM) rectifier\\/controlled-current PWM chopper link. Bidirectional power is accomplished by bidirectional current flow in the dc link for both modulators. The three-phase currents in

Masahiro Nishimoto; Juan W. Dixon; Ashok B. Kulkarni; Boon-Teck Ooi

1987-01-01

29

An integrated AC drive system using a controlled-current PWM rectifier\\/inverter link  

Microsoft Academic Search

Two identical three-phase, bipolar transistor, controlled-current, pulsewidth modulation (PWM) power modulators are integrated so that one functions as a rectifier and the other as an inverter in an AC drive system. The rectifier input currents maintain near-60-Hz sinusoidal waveforms with unity power factor. A leading power factor is also possible. The modulators do not depend on the availability of bidirectional

B. T. Ooi; JUAN W. DIXON; ASHOK B. KULKARNI; MASAHIRO NISHIMOTO

1988-01-01

30

Novel hybrid 12-pulse line interphase transformer boost-type rectifier with controlled output voltage  

Microsoft Academic Search

This paper describes two novel hybrid 12-pulse line interphase transformer rectifier systems with integrated single-switch or two-switch boost-type output stage. The boost stage allows controlling the output voltage to a constant value independent of line voltage or output power variations. In combination with low complexity and\\/or high reliability the hybrid rectifier concept therefore is of potential interest for supplying electrically

K. Mino; G. Gong; J. W. Kolar

2004-01-01

31

An adaptive direct power control for three-phase pwm rectifier in the unbalanced case  

Microsoft Academic Search

In this paper, a model based controller is proposed that directly controls the instantaneous active and reactive power of a PWM rectifier in the unbalanced case. Instrumental for our developments is the expression of the source voltage in terms of both sequences, positive and negative, which allows a more complete description of the model. The controller incorporates an adaptation mechanism

G. Escobar; M. F. Martinez-Montejano; R. E. Torres Olguin; A. A. Valdez

2008-01-01

32

Input Power Measurement Techniques for Single-Phase Digitally Controlled PFC Rectifiers  

E-print Network

are required for both "time-of-use" billing and system power management purposes. When a digitally controlled and a power measurement system using only data present in the digital controller or from a downstream DCInput Power Measurement Techniques for Single-Phase Digitally Controlled PFC Rectifiers Barry A

33

Control Improvement in Single-Phase Active Rectifier with Extended Functions  

Microsoft Academic Search

An active rectifier has two control objectives: DC voltage regulation and AC current tracking. These objectives are difficult to achieve when nonlinear loads are connected to the same AC mains or voltage sags occurs. In this paper a switched PI controller to regulate the bus voltage even when voltage sag occurs is presented. Moreover, with the control law proposed, an

Manuel Flota; Ciro Nez; Jess Lira; Ricardo lvarez; Felipe Pazos

2006-01-01

34

Passivity-Based Control for a Single-Phase, Full Bridge, Active Rectifier  

Microsoft Academic Search

An active rectifier has two control objectives: current tracking and voltage regulation. Against dynamic nonlinear loads or voltage sags it is difficult to achieve both objectives. This paper deals whit analysis, design and implementation a passivity-based control to track a current reference and a PI controller to regulate de DC bus voltage. Moreover, the bus regulation has adequately performance even

Manuel Flota; J. Lira; G. Nunez; R. Alvarez; F. Pazos

2006-01-01

35

Abstract--We are considering the problem of controlling inductions motors driven through AC/DC rectifiers and DC/AC  

E-print Network

/DC rectifiers and DC/AC inverters. The control objectives are threefold: (i) forcing the motor speed to track/AC inverter through a transformer and an AC/DC rectifier The connection line between the rectifier, undesirable current harmonics are likely to be generated in the AC line. These harmonics reduce the rectifier

Boyer, Edmond

36

A critical review of ohmic and rectifying contacts for silicon carbide  

Microsoft Academic Search

For more than three decades, SiC has been investigated as a wide band gap semiconductor. This paper reviews ohmic and rectifying metal contacts on n- and p-type ?- and ?-SiC reported throughout that time period. Electrical characteristics, Schottky barrier heights (SBHs), thermal stability, and chemical reactions are discussed. Most metals formed very good rectifying contacts in the as-deposited condition on

Lisa M. Porter; Robert F. Davis

1995-01-01

37

A New Robust Controller for a Three-Phase Three-Level NPC Rectifier  

Microsoft Academic Search

This paper presents a new control strategy for a three-phase, three-level, neutral point clamped (NPC) rectifier. The controller is a combination of three sub-controllers, one for each of the d-axis, q-axis and zero-sequence components of the converter dynamic model In the proposed control strategy, the zero-sequence and the q-axis sub-controllers are inner loop controllers, whereas the d-axis sub-controller acts as

A. F. Okou; M. Tarbouchi; D. Bouchard; A. A. Amoussou

2007-01-01

38

Indirect current control of a unity power factor sinusoidal current boost type three-phase rectifier  

Microsoft Academic Search

The indirect current control scheme has evolved from the success of the hysteresis current controlled voltage regulated rectifier, which has been shown to be capable of: unity and even leading power factor operation; near sinusoidal current waveforms; and bilateral power transfer without the need of bi-directional solid state power switches. The advance consists of replacing the inner hysteresis current feedback

J. W. Dixon; Boon-Teck Ooi

1988-01-01

39

Nonlinear partial state feedback controller for a single phase active rectifier  

Microsoft Academic Search

This paper presents a partial state feedback controller for an active rectifier to regulate dc output voltage and to guarantee a power factor close to unity. The partial information controller is based on the Exact Tracking Error Dynamics Passive Output Feedback (ETDPOF) technique in conjunction with an Immersion and Invariance based inductor current observer. Numerical simulations are presented to evaluate

Manuel Flota; Ricardo Alvarez-Salas; H. Rodriguez-Cortes; C. Nunez

2008-01-01

40

A comparative study of control techniques for PWM rectifiers in AC adjustable speed drives  

Microsoft Academic Search

Four control techniques for pulse-width modulation (PWM) rectifiers in AC adjustable speed drives are presented. In particular, the so-called virtual-flux oriented control (VFOC) and virtual-flux based direct power control (VF-DPC) schemes are described and compared with their voltage based counterparts. These are the voltage oriented control (VOC) and voltage-based direct power control (V-DPC) techniques. Theoretical background is provided, and results

Mariusz Malinowski; Marian P. Kazmierkowski; Andrzej M. Trzynadlowski

2003-01-01

41

Transistor as a Rectifier  

E-print Network

Transistor is a three terminal semiconductor device normally used as an amplifier or as a switch. Here the alternating current (a.c) rectifying property of the transistor is considered. The ordinary silicon diode exhibits a voltage drop of ~0.6V across its terminals. In this article it is shown that the transistor can be used to build a diode or rectify low current a.c (~mA) with a voltage drop of ~0.03V. This voltage is ~20 times smaller than the silicon diode. This article gives the half-wave and full-wave transistor rectifier configurations along with some applications to justify their usefulness.

Raju Baddi

2012-04-09

42

Transistor as a Rectifier  

E-print Network

Transistor is a three terminal semiconductor device normally used as an amplifier or as a switch. Here the alternating current (a.c) rectifying property of the transistor is considered. The ordinary silicon diode exhibits a voltage drop of ~0.6V across its terminals. In this article it is shown that the transistor can be used to build a diode or rectify low current a.c (~mA) with a voltage drop of ~0.03V. This voltage is ~20 times smaller than the silicon diode. This article gives the half-wave and full-wave transistor rectifier configurations along with some applications to justify their usefulness.

Baddi, Raju

2012-01-01

43

Average Current Mode Control of Three-Phase Boost Rectifiers with Low Harmonic Distortion Applied to Small Wind Turbines  

Microsoft Academic Search

This paper presents the application of average current mode control to reduce the THDi and increase the PF in a three-phase boost rectifier driving a small wind turbine. It is used as the input stage of small wind turbines with permanent magnet synchronous generators operating at variable speed.The boost rectifier output is connected to an inverter which injects the energy

O. C. Castillo; E. F. Amoros; G. G. Sanfeliu; L. Morales

2009-01-01

44

Robust dead-beat current control for PWM rectifiers and active filters  

Microsoft Academic Search

This paper analyzes the stability limitations of digital dead-beat current control applied to voltage-source three-phase converters used as pulsewidth modulation rectifiers and\\/or active filters. In these applications, the conventional control algorithm, as used in drive applications, is not sufficiently robust and stability problems may arise for the current control loop. The current loop is, indeed, particularly sensitive to any model

Luigi Malesani; Paolo Mattavelli; Simone Buso

1999-01-01

45

Control of three-phase PWM rectifier under unbalanced input voltage conditions without sequential component extraction  

Microsoft Academic Search

Many methods for control of three-phase boost-type PWM rectifier under unbalanced input voltage conditions have been presented in the last two decades. Among these methods, the input-output-power-control (IOPC) method seems the most desirable one offering ripple-free dc bus voltage, low-distortion input currents and average unity power factor on the grid side. Most of the IOPC schemes adopt rotating frame and

Zixin Li; Ping Wang; Yaohua Li; Haibin Zhu; Fanqiang Gao

2010-01-01

46

Nonlinear-carrier control for high-power-factor boost rectifiers  

Microsoft Academic Search

Novel nonlinear-carrier (NLC) controllers are proposed for high-power-factor boost rectifiers. In the NLC controllers, the switch duty ratio is determined by comparing a signal derived from the main switch current with a periodic, nonlinear carrier waveform. As a result, the average input current follows the input line voltage. The technique is suitable for boost converters operating in the continuous conduction

D. Maksimovic; Yungtaek Jang; Robert Erickson

1996-01-01

47

Predictive Current Control for Multilevel Active Rectifiers With Reduced Switching Frequency  

Microsoft Academic Search

In this paper, a new low-frequency predictive current control is proposed for a single-phase cascaded H-bridge multilevel rectifier. The control method has been fully investigated with theoretical analysis, simulation, and experiments on a laboratory prototype with five series-connected H-bridges. However, the analysis and technique are valid for any general level structure. The simulations and experimental results presented demonstrate the excellent

Pericle Zanchetta; David B. Gerry; Vito Giuseppe Monopoli; Jon C. Clare; Patrick W. Wheeler

2008-01-01

48

Voltage balancing control of diode-clamped multilevel rectifier\\/inverter systems  

Microsoft Academic Search

This paper presents a new voltage balancing control for the diode-clamped multilevel rectifier\\/inverter system. A complete analysis of the voltage balance theory for a five-level back-to-back system is given. The analysis is based on fundamental frequency switching control and then extended to pulsewidth modulation (PWM). The method involves obtaining optimal switching angles; a process that is described in detail herein.

Zhiguo Pan; Fang Zheng Peng; Keith A. Corzine; Victor R. Stefanovic; J. M. Leuthen; S. Gataric

2005-01-01

49

724 IEEE TRANSACTIONS ON POWER ELECTRONICS, VOL. 14, NO. 4, JULY 1999 A Fuzzy-Controlled Active Front-End Rectifier with  

E-print Network

Front-End Rectifier with Current Harmonic Filtering Characteristics and Minimum Sensing Variables Juan W (PWM) rectifiers to work simultaneously as active power filters is presented. The proposed control control scheme very simple. The active front-end rectifier acts directly on the mains line currents

Catholic University of Chile (Universidad Católica de Chile)

50

Single-Phase Half-Controlled Buck Rectifier Capable of Recovering Snubber Energy  

NASA Astrophysics Data System (ADS)

Single-phase half-controlled buck rectifier using a simple snubber energy recovery bridge leg is studied. When the active power devices assembled into this bridge leg are simultaneously turned on, the snubber capacitor is discharged and its stored energy is transferred to the load circuit. The experimental results confirm that the input current can be waveshaped sinusoidally with the higher efficiency than that of the conventional one.

Itoh, Ryozo; Ishizaka, Kouichi

51

Implementation of a controlled rectifier using AC-AC matrix converter theory  

Microsoft Academic Search

It is well known that a PWM-controlled rectifier can offer advantages of reduced low-order harmonics and unity input power factor when compared to a conventional thyristor converter. However, theoretically optimum PWM strategies are often difficult to implement physically or are not easily extended to regenerative operation. The authors propose an alternative PWM strategy based on AC-AC matrix converter theory, which

Donald G. Holmes; Thomas A. Lipo

1992-01-01

52

Power density spectrum estimation of the random controlled PWM single-phase boost rectifier  

Microsoft Academic Search

Random modulation is of increasing interest in power electronics and also holds promise for reducing filtering requirements in AC\\/AC, DC\\/DC converter applications and reducing acoustic noise in motor drive applications. This paper deals with the power spectrum density (PSD) estimation methods of the random controlled pulse width modulation (RPWM) single-phase structured boost rectifier. Estimated PSD is also experimentally verified. The

F. Mihalic; M. Milanovic

1999-01-01

53

A new control strategy for voltage-type PWM rectifiers to realize zero steady-state control error in input current  

Microsoft Academic Search

In this paper, a new simple control strategy for AC input current of voltage-type pulsewidth modulation (PWM) rectifiers which can eliminate the steady-state control error completely is proposed. This control method requires neither the instantaneous value of the supply voltage nor any accurate circuit parameters on the AC side of the rectifier. Thus, a robust operation against the variation of

Yukihiko Sato; Tomotsugu Ishizuka; Kazuyoshi Nezu; Teruo Kataoka

1998-01-01

54

A Comparative Study on Control Algorithm for Active Front-End Rectifier of Large Motor Drives Under Unbalanced Input  

Microsoft Academic Search

This paper investigates unbalance compensating con- trol algorithms for the active front-end rectifier employed in high-power motor drive systems. The generic voltage-source- converter topology of the three-level neutral-point clamped rectifier is selected for the comparative study. Three different control algorithms have been formulated based on the symmet- rical components and dq synchronous frames under general- ized unbalanced operating conditions. Control

Yongsug Suh; Yuran Go; Dohwan Rho

2011-01-01

55

High-performance digital triggering system for phase-controlled rectifiers  

SciTech Connect

The larger power supplies used to power accelerator magnets are most commonly polyphase rectifiers using phase control. While this method is capable of handling impressive amounts of power, it suffers from one serious disadvantage, namely that of subharmonic ripple. Since the stability of the stored beam depends to a considerable extent on the regulation of the current in the bending magnets, subharmonic ripple, especially that of low frequency, can have a detrimental effect. At the NSLS, we have constructed a 12-pulse, phase control system using digital signal processing techniques that essentially eliminates subharmonic ripple.

Olsen, R.E.

1983-01-01

56

Design and evaluation of a cellular rectifier system with distributed control  

E-print Network

This paper presents the design and experimental evaluation of a six-cell 6 kW cellular (parallel) rectifier system which operates at nearly unity power factor. The cellular rectifier system implements both distributed load ...

Perreault, David J.

57

An Integrated Power-Efficient Active Rectifier With Offset-Controlled High Speed Comparators for Inductively Powered Applications  

PubMed Central

We present an active full-wave rectifier with offset-controlled high speed comparators in standard CMOS that provides high power conversion efficiency (PCE) in high frequency (HF) range for inductively powered devices. This rectifier provides much lower dropout voltage and far better PCE compared to the passive on-chip or off-chip rectifiers. The built-in offset-control functions in the comparators compensate for both turn-on and turn-off delays in the main rectifying switches, thus maximizing the forward current delivered to the load and minimizing the back current to improve the PCE. We have fabricated this active rectifier in a 0.5-?m 3M2P standard CMOS process, occupying 0.18 mm2 of chip area. With 3.8 V peak ac input at 13.56 MHz, the rectifier provides 3.12 V dc output to a 500 ? load, resulting in the PCE of 80.2%, which is the highest measured at this frequency. In addition, overvoltage protection (OVP) as safety measure and built-in back telemetry capabilities have been incorporated in our design using detuning and load shift keying (LSK) techniques, respectively, and tested. PMID:22174666

Lee, Hyung-Min; Ghovanloo, Maysam

2011-01-01

58

An Integrated Power-Efficient Active Rectifier With Offset-Controlled High Speed Comparators for Inductively Powered Applications.  

PubMed

We present an active full-wave rectifier with offset-controlled high speed comparators in standard CMOS that provides high power conversion efficiency (PCE) in high frequency (HF) range for inductively powered devices. This rectifier provides much lower dropout voltage and far better PCE compared to the passive on-chip or off-chip rectifiers. The built-in offset-control functions in the comparators compensate for both turn-on and turn-off delays in the main rectifying switches, thus maximizing the forward current delivered to the load and minimizing the back current to improve the PCE. We have fabricated this active rectifier in a 0.5-?m 3M2P standard CMOS process, occupying 0.18 mm(2) of chip area. With 3.8 V peak ac input at 13.56 MHz, the rectifier provides 3.12 V dc output to a 500 ? load, resulting in the PCE of 80.2%, which is the highest measured at this frequency. In addition, overvoltage protection (OVP) as safety measure and built-in back telemetry capabilities have been incorporated in our design using detuning and load shift keying (LSK) techniques, respectively, and tested. PMID:22174666

Lee, Hyung-Min; Ghovanloo, Maysam

2011-01-01

59

Rectifying control of wire diameter during dieless drawing by a deformation measuring method of interframe displacement  

NASA Astrophysics Data System (ADS)

A deformation measurement method of interframe displacement was proposed in this paper. By online monitoring the shape dimensions of both the deformation zone and its adjacent zone by machine vision, the initial and terminative positions of deformation were dynamically identified during dieless drawing, and the global monitoring and online closed-loop control of the deformation zone were achieved. The dieless drawing process was systematically carried out on NiTi shape memory alloy wires. It is shown that the deformation measurement method of interframe displacement can track the axial displacement of the wires, but this cannot be achieved by traditional machine vision. The initial and terminative positions of deformation can be accurately identified by this method. The proposed rectifying control technology can effectively decrease the wire diameter fluctuation during dieless drawing, that is, the standard deviation of the wire diameter fluctuation could be decreased from 0.30 to 0.08 mm after three passes of dieless drawing, indicating that the control system has a good rectifying ability.

He, Yong; Liu, Xue-feng; Qin, Fang; Xie, Jian-xin

2012-07-01

60

DC Link Voltage and Supply-Side Current HarmonicsMinimization of Three Phase PWM BoostRectifiers Using Frequency Domain BasedRepetitive Current Controllers  

Microsoft Academic Search

This paper presents a digital plug-in frequency domain based repetitive control scheme for minimizing the odd order harmonics in the supply line side currents of the three phase pulsewidth modulation (PWM) boost rectifier under the distorted and unbalanced supply voltage conditions. Based on the mathematical model of the three-phase PWM boost rectifier under the generalized supply voltage conditions, the control

X. H. Wu; S. K. Panda; J. X. Xu

2008-01-01

61

Nanoscale Spin Seebeck Rectifier: Controlling Thermal Spin Transport across Insulating Magnetic Junctions with Localized Spin  

NASA Astrophysics Data System (ADS)

The spin Seebeck effect is studied across a charge insulating magnetic junction, in which thermal-spin conjugate transport is assisted by the exchange interactions between the localized spin in the center and electrons in metallic leads. We show that, in contrast with bulk spin Seebeck effect, the figure of merit of such nanoscale thermal-spin conversion can be infinite, leading to the ideal Carnot efficiency in the linear response regime. We also find that in the nonlinear spin Seebeck transport regime the device possesses the asymmetric and negative differential spin Seebeck effects. In the last, the situations with leaking electron tunneling are also discussed. This nanoscale thermal spin rectifier, by tuning the junction parameters, can act as a spin Seebeck diode, spin Seebeck transistor, and spin Seebeck switch, which could have substantial implications for flexible thermal and information control in molecular spin caloritronics.

Ren, Jie; Fransson, Jonas; Zhu, Jian-Xin

2014-06-01

62

Nanoscale Spin Seebeck Rectifier: Controlling Thermal Spin Transport across Insulating Magnetic Junctions with Localized Spin  

E-print Network

The spin Seebeck effect is studied across a charge insulating magnetic junction, in which thermal-spin conjugate transport is assisted by the exchange interactions between the localized spin in the center and electrons in metallic leads. We show that, in contrast with bulk spin Seebeck effect, the figure of merit of such nanoscale thermal-spin conversion can be infinite, leading to the ideal Carnot efficiency in the linear response regime. We also find that in the nonlinear spin Seebeck transport regime, the device possesses the asymmetric and negative differential spin Seebeck effects. In the last, the situations with leaking electron tunneling are also discussed. This nanoscale thermal spin rectifier, by tuning the junction parameters, can act as a spin Seebeck diode, spin Seebeck transistor and spin Seebeck switch, which could have substantial implications for flexible thermal and information control in molecular spin caloritronics.

Jie Ren; Jonas Fransson; Jian-Xin Zhu

2013-10-15

63

A novel control method for input output harmonic elimination of the PWM boost type rectifier under unbalanced operating conditions  

Microsoft Academic Search

This paper presents a new control strategy to improve the performance of the PWM boost type rectifier when operating under an unbalanced supply. An analytical solution for harmonic elimination under unbalanced input voltages is obtained resulting in a smooth (constant) power flow from AC to DC side in spite of the unbalanced voltage condition. Based on the analysis of the

Ana Vladan Stankovic; Thomas A. Lipo

2001-01-01

64

Performance investigation of a current-controlled voltage-regulated PWM rectifier in rotating and stationary frames  

Microsoft Academic Search

Active front-end rectifiers with reduced input current harmonics and high input power factor will be required in the near future for utility interfaced applications. In order to meet the new and more stringent regulations with force-commutated switches, the voltage source inverter approach is superior to the conventional current source approach, in terms of number of components and control options. However,

Navid R. Zargari; G. Joos

1995-01-01

65

Controllable step motors and rectifiers of magnetic flux quanta using periodic arrays of asymmetric pinning defects  

NASA Astrophysics Data System (ADS)

We study the transport of vortices in superconductors with regular arrays of asymmetric pinning wells when applying an alternating electrical current. The asymmetric traps are modelled by the superposition of two interpenetrating square lattices of weak and strong pinning centers with separation smaller than the lattice constant. We show that this system can induce a net rectifying or diode effect for the vortex motion, including collective step-motor-type dynamics, where many vortices move forward a controlled and exact number of pin-lattice spacings at each cycle of the ac driving force. This system exhibits a remarkable net dc response with striking sawtooth-type oscillations. The net dc voltage response Vdc of the ac-driven vortices versus both the half period P and the amplitude FL of the square wave ac drive has been detailed in the present work. The influence of the equilibrium thermal noise, the shift between the two pinning sublattices, the degree of translational and orientational disorder, and the size of the simulation system on the Vdc response of the vortex motion at ac drive has also been addressed. Devil staircase and Arnolds tongue structures are revealed. We also analytically derive all the key features of our numerical results. This system provides a very controllable stepmotor for the control of collective motion. Our results apply mutatis mutandis to arrays of Josephson junctions, colloidal systems with optical traps, Wigner crystals, and any system with repelling movable objects that can be pinned by a lattice of traps.

Zhu, B. Y.; Marchesoni, F.; Moshchalkov, V. V.; Nori, Franco

2003-07-01

66

Design and control of an LCL-filter based three-phase active rectifier  

Microsoft Academic Search

The aim of the paper is to propose a design procedure for an LCL-filter in a front-end three-phase active rectifier. The main goal is to ensure a reduction of the switching frequency ripple at a reasonable cost and, at the same time, to obtain a high performance rectifier. In this paper a step-by-step procedure for designing an LCL-filter is proposed

Marco Liserre; Frede Blaabjerg; Steffan Hansen

2001-01-01

67

Design and control of an LCL-filter-based three-phase active rectifier  

Microsoft Academic Search

This paper proposes a step-by-step procedure for designing the LCL filter of a front-end three-phase active rectifier. The primary goal is to reduce the switching frequency ripple at a reasonable cost, while at the same time achieving a high-performance front-end rectifier (as characterized by a rapid dynamic response and good stability margin). An example LCL filter design is reported and

Marco Liserre; Frede Blaabjerg; Steffan Hansen

2005-01-01

68

Current control of a 3-level rectifier\\/inverter drive system  

Microsoft Academic Search

The marriage of a three-level voltage source inverter with a force-commutated three-level rectifier is examined in this paper. Three-level inverters are capable of reducing the output current harmonics dramatically compared with typical two-level inverters whereas a three-level rectifier of this type allows nearly sinusoidal input currents at unity fundamental power factor on the utility side of the drive system. The

Michael C. Klabunde; Yifan Zhao; T.A. Lipo

1994-01-01

69

An Output-Power-Control Strategy for a Three-Phase PWM Rectifier Under Unbalanced Supply Conditions  

Microsoft Academic Search

Instantaneous power regulation is an effective way to improve the performance of a pulsewidth-modulation rectifier operating under unbalanced supply-voltage conditions. By properly setting current commands, this approach aims to achieve performance features that are normally achievable only under ideal balanced operating conditions. This paper proposes an instantaneous power-regulation strategy called output-power-control method, in which the current commands are determined so

Bo Yin; Ramesh Oruganti; Sanjib Kumar Panda; Ashoka K. S. Bhat

2008-01-01

70

Reduction of voltage stress in integrated high-quality rectifier-regulators by variable-frequency control  

Microsoft Academic Search

The Integrated High-Quality Rectifier-Regulators (IHQRRs) suffer from relatively high stress on the internal-energy storage capacitor and, consequently, on primary-side semiconductors. As a result, they are not practical in applications with the universal input-voltage range. In this paper, a variable-frequency control that reduces the voltage stress and makes the IHQRRs suitable for universal input-range applications is described. Evaluation results of a

Milan M. JovanoviC; Dan M. C. Tsang; Fred C. Lee

1994-01-01

71

Transformer-rectifier flux pump using inductive current transfer and thermally controlled Nb(3)Sn cryotrons.  

PubMed

Transformer-rectifier flux pumps using thermally switched Nb(3)Sn cryotrons are being investigated as a loss make-up device for the proposed isochorically operated (sealed) superconducting magnets for the Canadian Maglev vehicle. High currents (1000 A) were obtained in an experimental flux pump using inductive current transfer and operating at 2 Hz. PMID:18699368

Atherton, D L; Davies, R

1979-10-01

72

1Rectifier Device Data Standard Recovery Rectifiers  

E-print Network

1Rectifier Device Data Axial Lead Standard Recovery Rectifiers This data sheet provides information on subminiature size, axial lead mounted rectifiers for general­purpose low­power applications. Mechanical Reverse Voltage VR(RMS) 35 70 140 280 420 560 700 Volts *Average Rectified Forward Current (single phase

Wedeward, Kevin

73

Silicon Microvalves For Gas Flow Control  

Microsoft Academic Search

Four silicon gas valve technologies have emerged in the past decade and are beginning to compete with conventional solenoid valves. In some applications including proportional control they offer superior flow characteristics, smaller size, smaller weight, or a combination of these advantages. This paper describes the four valve technologies (sealed fluid capsule expansion, aluminum\\/silicon bimetal, shape-memory alloy, and nickel\\/silicon bimetal) which

Phillip W. Barth

1995-01-01

74

Design and evaluation of a PWM rectifier control system for testing renewable DC sources connected to the grid  

Microsoft Academic Search

Voltage source PWM rectifiers connected to the AC grid are increasingly used in different applications like stand alone power supplies, high-efficiency regenerative AC drives and grid-connected renewable energies. Fast dynamics, sinusoidal input current, and unity power factor justify its wide application. The overall system performance is strongly dependent on the PWM rectifier characteristics. The main performance indices are related to

N. Silva; A. Martins; A. Carvalho

2006-01-01

75

Simple Diode Rectifier Circuit  

NSDL National Science Digital Library

This website from the Thayer School of Engineering at Dartmouth College features an animation of a simple diode rectifier circuit. A rectifier is an electrical device that converts alternating current (AC) to direct current (DC), a process known as rectification.

2012-10-24

76

Control of rectification and permeation by residues in two distinct domains in an inward rectifier K + channel  

Microsoft Academic Search

Inwardly rectifying K+ channels conduct more inward than outward current as a result of voltage-dependent block of the channel pore by intracellular Mg2+ and polyamines. We investigated the molecular mechanism and structural determinants of inward rectification and ion permeation in a strongly rectifying channel, IRK1. Block by Mg2+ and polyamines is found not to conform to one-to-one binding, suggesting that

Jian Yang; Yuh Nung Jan; Lily Y Jan

1995-01-01

77

A DSP-based implementation of a nonlinear model reference adaptive control for a three-phase three-level NPC boost rectifier prototype  

Microsoft Academic Search

In this paper, the design and the implementation of a model reference adaptive control (MRAC) applied to a three-phase three-level neutral-point-clamped (NPC) boost rectifier are presented. This control strategy is developed with a view to regulate dc output and neutral point voltages and to reduce the influence of parameter variations while maintaining unity power factor. A nonlinear multiple-input multiple-output (MIMO)

Loubna Yacoubi; Kamal Al-Haddad; L.-A. Dessaint; F. Fnaiech

2005-01-01

78

A four level rectifier-inverter system for drive applications  

Microsoft Academic Search

Multilevel converter technology has been receiving increased attention, especially for high power applications. In particular, three level drive systems have been extensively reported. In this paper, a four level rectifier-inverter system is investigated for drive applications. A dynamic control algorithm is described which balances the voltages on a 4 level rectifier-inverter drive system primarily from the rectifier. The proposed control

Gautam Sinha; T.A. Lipo

1996-01-01

79

A transparent cell-culture microchamber with a variably controlled concentration gradient generator and flow field rectifier.  

PubMed

Real-time observation of cell growth provides essential information for studies such as cell migration and chemotaxis. A conventional cell incubation device is usually too clumsy for these applications. Here we report a transparent microfluidic device that has an integrated heater and a concentration gradient generator. A piece of indium tin oxide (ITO) coated glass was ablated by our newly developed visible laser-induced backside wet etching (LIBWE) so that transparent heater strips were prepared on the glass substrate. A polymethylmethacrylate (PMMA) microfluidic chamber with flow field rectifiers and a reagent effusion hole was fabricated by a CO(2) laser and then assembled with the ITO heater so that the chamber temperature can be controlled for cell culturing. A variable chemical gradient was generated inside the chamber by combining the lateral medium flow and the flow from the effusion hole. Successful culturing was performed inside the device. Continuous long-term (>10 days) observation on cell growth was achieved. In this work the flow field, medium replacement, and chemical gradient in the microchamber are elaborated. PMID:19693408

Cheng, Ji-Yen; Yen, Meng-Hua; Kuo, Ching-Te; Young, Tai-Horng

2008-01-01

80

Automatic Control of Silicon Melt Level  

NASA Technical Reports Server (NTRS)

A new circuit, when combined with melt-replenishment system and melt level sensor, offers continuous closed-loop automatic control of melt-level during web growth. Installed on silicon-web furnace, circuit controls melt-level to within 0.1 mm for as long as 8 hours. Circuit affords greater area growth rate and higher web quality, automatic melt-level control also allows semiautomatic growth of web over long periods which can greatly reduce costs.

Duncan, C. S.; Stickel, W. B.

1982-01-01

81

Silicon-controlled-rectifier square-wave inverter with protection against commutation failure  

NASA Technical Reports Server (NTRS)

The square-wave SCR inverter that was designed, built, and tested includes a circuit to turn off the inverter in case of commutation failure. The basic power stage is a complementary impulse-commutated parallel inverter consisting of only six components. The 400-watt breadboard was tested while operating at + or - 28 volts, and it had a peak efficiency of 95.5 percent at 60 hertz and 91.7 percent at 400 hertz. The voltage regulation for a fixed input was 3 percent at 60 hertz. An analysis of the operation and design information is included.

Birchenough, A. G.

1971-01-01

82

Silicon controlled rectifier polyphase bridge inverter commutated with gate-turn-off thyristor  

NASA Technical Reports Server (NTRS)

A polyphase SCR inverter (10) having N switching poles, each comprised of two SCR switches (1A, 1B; 2A, 2B . . . NA, NB) and two diodes (D1B; D1B; D2A, D2B . . . DNA, DNB) in series opposition with saturable reactors (L1A, L1B; L2A, L2B . . . LNA, LNB) connecting the junctions between the SCR switches and diodes to an output terminal (1, 2 . . . 3) is commutated with only one GTO thyristor (16) connected between the common negative terminal of a dc source and a tap of a series inductor (14) connected to the positive terminal of the dc source. A clamp winding (22) and diode (24) are provided, as is a snubber (18) which may have its capacitance (c) sized for maximum load current divided into a plurality of capacitors (C.sub.1, C.sub.2 . . . C.sub.N), each in series with an SCR switch S.sub.1, S.sub.2 . . . S.sub.N). The total capacitance may be selected by activating selected switches as a function of load current. A resistor 28 and SCR switch 26 shunt reverse current when the load acts as a generator, such as a motor while braking.

Edwards, Dean B. (Inventor); Rippel, Wally E. (Inventor)

1986-01-01

83

Fabrication, characterization, and the rectifying properties of the interfacial structural controlled LaSrMnO-Si heterojunctions  

SciTech Connect

The La{sub 0.9}Sr{sub 0.1}MnO{sub 3}/Si p-n junctions with optimized rectifying properties were synthesized using radio frequency magnetron sputtering followed by an in situ annealing process at a series of temperatures. The thickness of the SiO{sub x} barrier layer d determines the rectifying properties of the heterojunctions by Id{sup 3}=constant (I is the rectifying current). The dead layer was determined to act as a semiconductor layer in the conduction process. The annealed samples show Mn{sup 4+} rich interface which correlated closely to the electrical transportation properties of the heterostructures. Lowering the annealing temperature, the electric sensitivity of the heterojunction can be significantly enhanced by simply tuning the thickness of the barrier layer.

Wang, K.; Han, X. D.; Zhang, Z.; Li, T.; Zhang, M.; Yan, H. [Institute of Microstructure and Property of Advanced Materials, Beijing University of Technology, Beijing 100022 (China); Laboratory of Thin Film Materials, Beijing University of Technology, Beijing 100022 (China)

2008-01-01

84

The inwardly rectifying K+ channel KIR7.1 controls uterine excitability throughout pregnancy  

PubMed Central

Abnormal uterine activity in pregnancy causes a range of important clinical disorders, including preterm birth, dysfunctional labour and post-partum haemorrhage. Uterine contractile patterns are controlled by the generation of complex electrical signals at the myometrial smooth muscle plasma membrane. To identify novel targets to treat conditions associated with uterine dysfunction, we undertook a genome-wide screen of potassium channels that are enriched in myometrial smooth muscle. Computational modelling identified Kir7.1 as potentially important in regulating uterine excitability during pregnancy. We demonstrate Kir7.1 current hyper-polarizes uterine myocytes and promotes quiescence during gestation. Labour is associated with a decline, but not loss, of Kir7.1 expression. Knockdown of Kir7.1 by lentiviral expression of miRNA was sufficient to increase uterine contractile force and duration significantly. Conversely, overexpression of Kir7.1 inhibited uterine contractility. Finally, we demonstrate that the Kir7.1 inhibitor VU590 as well as novel derivative compounds induces profound, long-lasting contractions in mouse and human myometrium; the activity of these inhibitors exceeds that of other uterotonic drugs. We conclude Kir7.1 regulates the transition from quiescence to contractions in the pregnant uterus and may be a target for therapies to control uterine contractility. PMID:25056913

McCloskey, Conor; Rada, Cara; Bailey, Elizabeth; McCavera, Samantha; van den Berg, Hugo A; Atia, Jolene; Rand, David A; Shmygol, Anatoly; Chan, Yi-Wah; Quenby, Siobhan; Brosens, Jan J; Vatish, Manu; Zhang, Jie; Denton, Jerod S; Taggart, Michael J; Kettleborough, Catherine; Tickle, David; Jerman, Jeff; Wright, Paul; Dale, Timothy; Kanumilli, Srinivasan; Trezise, Derek J; Thornton, Steve; Brown, Pamela; Catalano, Roberto; Lin, Nan; England, Sarah K; Blanks, Andrew M

2014-01-01

85

The inwardly rectifying K+ channel KIR7.1 controls uterine excitability throughout pregnancy.  

PubMed

Abnormal uterine activity in pregnancy causes a range of important clinical disorders, including preterm birth, dysfunctional labour and post-partum haemorrhage. Uterine contractile patterns are controlled by the generation of complex electrical signals at the myometrial smooth muscle plasma membrane. To identify novel targets to treat conditions associated with uterine dysfunction, we undertook a genome-wide screen of potassium channels that are enriched in myometrial smooth muscle. Computational modelling identified Kir7.1 as potentially important in regulating uterine excitability during pregnancy. We demonstrate Kir7.1 current hyper-polarizes uterine myocytes and promotes quiescence during gestation. Labour is associated with a decline, but not loss, of Kir7.1 expression. Knockdown of Kir7.1 by lentiviral expression of miRNA was sufficient to increase uterine contractile force and duration significantly. Conversely, overexpression of Kir7.1 inhibited uterine contractility. Finally, we demonstrate that the Kir7.1 inhibitor VU590 as well as novel derivative compounds induces profound, long-lasting contractions in mouse and human myometrium; the activity of these inhibitors exceeds that of other uterotonic drugs. We conclude Kir7.1 regulates the transition from quiescence to contractions in the pregnant uterus and may be a target for therapies to control uterine contractility. PMID:25056913

McCloskey, Conor; Rada, Cara; Bailey, Elizabeth; McCavera, Samantha; van den Berg, Hugo A; Atia, Jolene; Rand, David A; Shmygol, Anatoly; Chan, Yi-Wah; Quenby, Siobhan; Brosens, Jan J; Vatish, Manu; Zhang, Jie; Denton, Jerod S; Taggart, Michael J; Kettleborough, Catherine; Tickle, David; Jerman, Jeff; Wright, Paul; Dale, Timothy; Kanumilli, Srinivasan; Trezise, Derek J; Thornton, Steve; Brown, Pamela; Catalano, Roberto; Lin, Nan; England, Sarah K; Blanks, Andrew M

2014-09-01

86

Substituting transistor for diode improves rectifying means  

NASA Technical Reports Server (NTRS)

Unusual transistor connection that substitutes for a silicon diode and allows significantly higher repetition rates without increasing power loss rectifies an alternating current. Operation speed is improved by a factor of 10 or more when a given diode is replaced by this transistor circuit.

Muller, R. M.

1966-01-01

87

Control of silicon nanoparticle size embedded in silicon oxynitride dielectric matrix  

NASA Astrophysics Data System (ADS)

In this study, silicon rich silicon oxynitride layers containing more than 15% nitrogen were deposited by electron cyclotron resonance assisted plasma enhanced vapor deposition in order to form silicon nanoparticles after a high temperature thermal annealing. The effect of the flows of the precursor gases on the composition and the structural properties of the layers was assessed by Rutherford backscattering spectroscopy, elastic recoil detection analysis, and infrared spectroscopic measurements. The morphological and crystallinity properties were investigated by energy filtered transmission electron microscopy and Raman spectroscopy. We show that the excess of silicon in the silicon oxynitride layer controls the silicon nanoparticles size. On the other hand, the crystalline fraction of particles is found to be strongly correlated to the nanoparticle size. Finally, the photoluminescence measurements show that it is also possible to tune the photoluminescence peak position between 400 and 800 nm and its intensity by changing the silicon excess in the silicon rich silicon oxynitride matrix.

Ehrhardt, F.; Ferblantier, G.; Muller, D.; Ulhaq-Bouillet, C.; Rinnert, H.; Slaoui, A.

2013-07-01

88

Control of silicon nanoparticle size embedded in silicon oxynitride dielectric matrix  

SciTech Connect

In this study, silicon rich silicon oxynitride layers containing more than 15% nitrogen were deposited by electron cyclotron resonance assisted plasma enhanced vapor deposition in order to form silicon nanoparticles after a high temperature thermal annealing. The effect of the flows of the precursor gases on the composition and the structural properties of the layers was assessed by Rutherford backscattering spectroscopy, elastic recoil detection analysis, and infrared spectroscopic measurements. The morphological and crystallinity properties were investigated by energy filtered transmission electron microscopy and Raman spectroscopy. We show that the excess of silicon in the silicon oxynitride layer controls the silicon nanoparticles size. On the other hand, the crystalline fraction of particles is found to be strongly correlated to the nanoparticle size. Finally, the photoluminescence measurements show that it is also possible to tune the photoluminescence peak position between 400 and 800 nm and its intensity by changing the silicon excess in the silicon rich silicon oxynitride matrix.

Ehrhardt, F.; Ferblantier, G.; Muller, D.; Slaoui, A. [ICube, Strasbourg University-CNRS, 23 rue du Loess BP20, 67037 Strasbourg Cedex 2 (France); Ulhaq-Bouillet, C. [IPCMS, Strasbourg University-CNRS, 23 rue du Loess BP43, 67034 Strasbourg Cedex 2 (France); Rinnert, H. [IJL, CNRS, Campus Victor Grignard BP 70239, 54506 Vandoeuvre-les-Nancy Cedex (France)

2013-07-21

89

Optimal-regulator-based control of NPC boost rectifiers for unity power factor and reduced neutral-point-potential variations  

Microsoft Academic Search

Neutral-point-clamped pulsewidth modulation rectifiers (NPCRs) are suitable for high-voltage systems because of their circuit structure. The NPCRs, however, have a problem, in that the neutral point potential (NPP) varies when the current flows into or out of the neutral point. The variations cause voltage deviations in the input waveforms, as well as unbalanced voltage stress on the devices. This paper

Shoji Fukuda; Yasumasa Matsumoto; Akira Sagawa

1999-01-01

90

Noise Properties of Rectifying Nanopores  

SciTech Connect

Ion currents through three types of rectifying nanoporous structures are studied and compared for the first time: conically shaped polymer nanopores, glass nanopipettes, and silicon nitride nanopores. Time signals of ion currents are analyzed by power spectrum. We focus on the low-frequency range where the power spectrum magnitude scales with frequency, f, as 1/f. Glass nanopipettes and polymer nanopores exhibit non-equilibrium 1/f noise, thus the normalized power spectrum depends on the voltage polarity and magnitude. In contrast, 1/f noise in rectifying silicon nitride nanopores is of equilibrium character. Various mechanisms underlying the voltage-dependent 1/f noise are explored and discussed, including intrinsic pore wall dynamics, and formation of vortices and non-linear flow patterns in the pore. Experimental data are supported by modeling of ion currents based on the coupled Poisson-Nernst-Planck and Navier Stokes equations. We conclude that the voltage-dependent 1/f noise observed in polymer and glass asymmetric nanopores might result from high and asymmetric electric fields inducing secondary effects in the pore such as enhanced water dissociation.

Powell, M R; Sa, N; Davenport, M; Healy, K; Vlassiouk, I; Letant, S E; Baker, L A; Siwy, Z S

2011-02-18

91

Noise Properties of Rectifying Nanopore  

SciTech Connect

Ion currents through three types of rectifying nanoporous structures are studied and compared: conically shaped polymer nanopores, glass nanopipettes, and silicon nitride nanopores. Time signals of ion currents are analyzed by the power spectrum. We focus on the low-frequency range where the power spectrum magnitude scales with frequency, f, as 1/f. Glass nanopipettes and polymer nanopores exhibit nonequilibrium 1/f noise; thus, the normalized power spectrum depends on the voltage polarity and magnitude. In contrast, 1/f noise in rectifying silicon nitride nanopores is of equilibrium character. Various mechanisms underlying the voltage-dependent 1/f noise are explored and discussed, including intrinsic pore wall dynamics and formation of vortices and nonlinear flow patterns in the pore. Experimental data are supported by modeling of ion currents based on the coupled Poisson-Nernst-Planck and Navier-Stokes equations. We conclude that the voltage-dependent 1/f noise observed in polymer and glass asymmetric nanopores might result from high and asymmetric electric fields, inducing secondary effects in the pore, such as enhanced water dissociation.

Vlassiouk, Ivan V [ORNL

2011-01-01

92

A novel ZVS Z-source rectifier  

Microsoft Academic Search

This paper proposes a novel ZVS Z-source rectifier, describes the operating principle, control strategy, and superiority. The three-phase ZVS Z-source rectifier implements the zero voltage turn-on (ZVS) for power transistors and zero-current turn-off (ZCOFF) for diodes without any additional circuits. It can buck and boost input voltage, and increase the reliability of the circuit. Thus it provides a low-cost, reliable,

Xinping Ding; Zhaoming Qian; Yeyuan Xie; Fang Z. Peng

2006-01-01

93

Efficient rectifying antenna  

NASA Technical Reports Server (NTRS)

Rectifying antenna comprised of 17 subarrays positioned closely together to intercept microwave beam features low cost, high conversion efficiency, and high power handling capability. Tests demonstrate efficiency level of 82 percent in converting RF to dc.

Dickinson, R. M.; Brown, W. C.

1979-01-01

94

Surface control of luminescence in silicon nanoparticles  

NASA Astrophysics Data System (ADS)

The intensity of visible photoluminescence from thin films of silicon nanoparticles is shown to be dependent upon the degree of surface passivation on the nanoparticles, while the emission energy is independent of the specific chemical nature of the passivating species. Nanoparticles are deposited into films using a pulsed laser ablation supersonic expansion source. Surface chemistry is controlled with a variety of postdeposition processing steps, including acid, methanol, and iodine treatments. These steps are then correlated with the visible photoluminescence behavior of the sample and the surface chemistry as characterized by x-ray photoelectron spectroscopy. Surface passivation controls the emission intensity through the elimination of competing nonradiative carrier relaxation pathways. The chemical nature of the passivating species does not determine the emission energy and can be easily changed with no anomalous photoluminescence behavior resulting. All results are consistent with a simple quantum confinement model of emission where particle size determines emission energy and surface passivation determines emission intensity.

Seraphin, A. A.; Ngiam, S.-T.; Kolenbrander, K. D.

1996-12-01

95

Coherent control of Rydberg states in silicon.  

PubMed

Laser cooling and electromagnetic traps have led to a revolution in atomic physics, yielding dramatic discoveries ranging from Bose-Einstein condensation to the quantum control of single atoms. Of particular interest, because they can be used in the quantum control of one atom by another, are excited Rydberg states, where wavefunctions are expanded from their ground-state extents of less than 0.1 nm to several nanometres and even beyond; this allows atoms far enough apart to be non-interacting in their ground states to strongly interact in their excited states. For eventual application of such states, a solid-state implementation is very desirable. Here we demonstrate the coherent control of impurity wavefunctions in the most ubiquitous donor in a semiconductor, namely phosphorus-doped silicon. In our experiments, we use a free-electron laser to stimulate and observe photon echoes, the orbital analogue of the Hahn spin echo, and Rabi oscillations familiar from magnetic resonance spectroscopy. As well as extending atomic physicists' explorations of quantum phenomena to the solid state, our work adds coherent terahertz radiation, as a particularly precise regulator of orbitals in solids, to the list of controls, such as pressure and chemical composition, already familiar to materials scientists. PMID:20577211

Greenland, P T; Lynch, S A; van der Meer, A F G; Murdin, B N; Pidgeon, C R; Redlich, B; Vinh, N Q; Aeppli, G

2010-06-24

96

Artificial neural networks for control of a grid-connected rectifier/inverter under disturbance, dynamic and power converter switching conditions.  

PubMed

Three-phase grid-connected converters are widely used in renewable and electric power system applications. Traditionally, grid-connected converters are controlled with standard decoupled d-q vector control mechanisms. However, recent studies indicate that such mechanisms show limitations in their applicability to dynamic systems. This paper investigates how to mitigate such restrictions using a neural network to control a grid-connected rectifier/inverter. The neural network implements a dynamic programming algorithm and is trained by using back-propagation through time. To enhance performance and stability under disturbance, additional strategies are adopted, including the use of integrals of error signals to the network inputs and the introduction of grid disturbance voltage to the outputs of a well-trained network. The performance of the neural-network controller is studied under typical vector control conditions and compared against conventional vector control methods, which demonstrates that the neural vector control strategy proposed in this paper is effective. Even in dynamic and power converter switching environments, the neural vector controller shows strong ability to trace rapidly changing reference commands, tolerate system disturbances, and satisfy control requirements for a faulted power system. PMID:24807951

Li, Shuhui; Fairbank, Michael; Johnson, Cameron; Wunsch, Donald C; Alonso, Eduardo; Proao, Julio L

2014-04-01

97

A New Three-Phase Rectifier for Regenerative Braking Application  

Microsoft Academic Search

This paper proposes a new regenerative rectifier for motor loads. The controller is implemented with simple analog components. Yet, it has the power of controlling a three-phase Voltage Source Inverter to operate either as a Power Factor Correction rectifier or as a Grid Connected Inverter according to motor's operational status. In both cases, the currents are sinusoidal. A 5 KW

Lihua Li; Keyue Smedley; Taotao Jin

2007-01-01

98

Diodes and Rectifiers  

NSDL National Science Digital Library

Written by Tony R. Kuphaldt, this chapter of All About Circuit's third volume on Semiconductors describes the physics behind diodes and rectifiers. The chapter is divided into fourteen sections on topics including diode ratings, voltage multipliers, and zener diodes. Each section has clear illustrations and examples, and most have a concise, bulleted review of what was covered at the end of the page. This is an excellent resource for educators in physics and electronic engineering classrooms to introduce lessons or units on semiconductors, diodes, and rectifiers. [ASC

Kuphaldt, Tony R.

2008-07-02

99

Diameter control of Ti-catalyzed silicon nanowires  

NASA Astrophysics Data System (ADS)

Titanium silicide nanoparticles on silicon substrates catalyze the decomposition of a silicon-containing gas, resulting in accelerated growth of silicon in one direction to form nanowires. Under some processing conditions, however, the Ti-catalyzed growth results in tapered silicon nanowires. The tapered nanowires are typically several microns long with diameters of tens of nanometers near the base and less than 10 nanometers at the tip. We show that the tapering is caused by uncatalyzed deposition of silicon on the sidewalls of the growing nanowires. We demonstrate that introducing chlorine-containing species in the gas phase greatly inhibits the uncatalyzed silicon deposition rate, thus yielding nanowires with uniform diameter along their length. Controlling the nanowire diameter along its length is essential for novel nanowire-based electronic, optical, and optoelectronic applications.

Sharma, S.; Kamins, T. I.; Williams, R. Stanley

2004-07-01

100

Method of controlling defect orientation in silicon crystal ribbon growth  

NASA Technical Reports Server (NTRS)

The orientation of twinning and other effects in silicon crystal ribbon growth is controlled by use of a starting seed crystal having a specific (110) crystallographic plane and (112) crystallographic growth direction.

Leipold, M. H. (inventor)

1978-01-01

101

Bridge Rectifier Animation  

NSDL National Science Digital Library

This is an animation of a bridge rectifier circuit or diode bridge. Voltages and parts of the circuit of this 3-D animated gif are highlighted with different colors. Current is displayed by green arrows indicating directional flow. The animation requires a Web browser or other video player software capable of displaying gif animations. A link provides an optional Quicktime version of this same animation.Other 3-D Circuit Animations can be seen here.

2009-11-26

102

The single-phase single-switch PWM three-level high power factor rectifier for DC network application  

Microsoft Academic Search

In this paper, a new unidirectional three-level rectifier is presented to draw sinusoidal line current with low THD and unity power factor. The adopted rectifier consists of a diode bridge, a power switch and two blocking diodes. Low cost, simple structure and convenient control are the main advantages of this rectifier. A two loop controller is developed to control the

Seied Nima Hoseini Eimeni; Ahmad Radan; Majid Mehrasa

2009-01-01

103

Controlling cellular activity by manipulating silicone surface roughness.  

PubMed

Silicone elastomers exhibit a broad range of beneficial properties that are exploited in biomaterials. In some cases, however, problems can arise at silicone elastomer interfaces. With breast implants, for example, the fibrous capsule that forms at the silicone interface can undergo contracture, which can lead to the need for revision surgery. The relationship between surface topography and wound healing--which could impact on the degree of contracture--has not been examined in detail. To address this, we prepared silicone elastomer samples with rms surface roughnesses varying from 88 to 650 nm and examined the growth of 3T3 fibroblasts on these surfaces. The PicoGreen assay demonstrated that fibroblast growth decreased with increases in surface roughness. Relatively smooth (approximately 88 nm) PDMS samples had ca. twice as much fibroblast DNA per unit area than the 'bumpy' (approximately 378 nm) and very rough (approximately 604 and approximately 650 nm) PDMS samples. While the PDMS sample with roughness of approximately 650 nm had significantly fewer fibroblasts at 24h than the TCP control, fibroblasts on the smooth silicone surprisingly reached confluence much more rapidly than on TCP, the gold standard for cell culture. Thus, increasing the surface roughness at the sub-micron scale could be a strategy worthy of consideration to help mitigate fibroblast growth and control fibrous capsule formation on silicone elastomer implants. PMID:20363600

Prasad, Babu R; Brook, Michael A; Smith, Terry; Zhao, Shigui; Chen, Yang; Sheardown, Heather; D'souza, Renita; Rochev, Yuri

2010-07-01

104

PRINCIPAL VALUES FOR RIESZ TRANSFORMS AND RECTIFIABILITY  

E-print Network

PRINCIPAL VALUES FOR RIESZ TRANSFORMS AND RECTIFIABILITY XAVIER TOLSA Abstract. Let E Rd with Hn (E) rectifiable exists. One says that a subset E Rd is n-rectifiable if there exists a countable family of n

Tolsa, Xavier

105

RECTIFIABILITY OF FLAT CHAINS Brian White  

E-print Network

RECTIFIABILITY OF FLAT CHAINS Brian) that a fin* *ite-mass flat chain over any coefficient group is rectifiable if and only if almos* *t all of its 0- dimensional slices are rectifiable. This implies that every flat chain of

White, Brian

106

A quasisymmetric surface with no rectifiable curves  

E-print Network

A quasisymmetric surface with no rectifiable curves of R3 to itself such that the image of R2 x {0} contains no rectifiable curves. 1991, rectifiable curves, Jacobian. ____________________________ 1Supported in part by NSF grant # DMS 95

Bishop, Christopher

107

Even-harmonics concerns at an industrial facility using a large number of half-controlled rectifiers  

Microsoft Academic Search

This paper documents a case study at an industrial facility that uses a large number of half-controlled heater drives. Voltage and current waveforms, along with harmonic spectrums, are gathered from different locations within the facility. A harmonic interaction problem that caused failures in the pulse width modulated adjustable speed drives (PWM ASDs) that were installed in the existing air handling

Arshad Mansoor; Jim McGee; Fang Zheng Peng

1998-01-01

108

Growth control of tungsten oxide nanostructures on planar silicon substrates  

Microsoft Academic Search

Tungsten oxide nanostructures were deposited on silicon substrates by a thermal oxidation approach. The major factors influencing their phase structure and growth morphology were found to be the substrate temperature and the chamber pressure. By investigating the growth process of these nanostructures, a phase growth diagram was constructed, with which one can realize the phase selection and morphology control of

Floriane Galla; Zhengcao Li; Zhengjun Zhang

2006-01-01

109

Superhydrophobic nanostructured silicon surfaces with controllable broadband reflectance.  

PubMed

Nanostructured superhydrophobic silicon surfaces with tunable reflectance are fabricated via a simple maskless deep reactive-ion etching process. By controlling the scale of the high-aspect-ratio nanostructures on a wafer-scale surface, surface reflectance is maximized or minimized over the UV-vis-IR range while maintaining superhydrophobic properties. PMID:21523314

Cho, Seong J; An, Taechang; Kim, Jin Young; Sung, Jungwoo; Lim, Geunbae

2011-06-01

110

Treatment to Control Adhesion of Silicone-Based Elastomers  

NASA Technical Reports Server (NTRS)

Seals are used to facilitate the joining of two items, usually temporarily. At some point in the future, it is expected that the items will need to be separated. This innovation enables control of the adhesive properties of silicone-based elastomers. The innovation may also be effective on elastomers other than the silicone-based ones. A technique has been discovered that decreases the level of adhesion of silicone- based elastomers to negligible levels. The new technique causes less damage to the material compared to alternative adhesion mitigation techniques. Silicone-based elastomers are the only class of rubber-like materials that currently meet NASA s needs for various seal applications. However, silicone-based elastomers have natural inherent adhesive properties. This stickiness can be helpful, but it can frequently cause problems as well, such as when trying to get items apart. In the past, seal adhesion was not always adequately addressed, and has caused in-flight failures where seals were actually pulled from their grooves, preventing subsequent spacecraft docking until the seal was physically removed from the flange via an extravehicular activity (EVA). The primary method used in the past to lower elastomer seal adhesion has been the application of some type of lubricant or grease to the surface of the seal. A newer method uses ultraviolet (UV) radiation a mixture of UV wavelengths in the range of near ultraviolet (NUV) and vacuum ultraviolet (VUV) wavelengths.

deGroh, Henry C., III; Puleo, Bernadette J.; Waters, Deborah L.

2013-01-01

111

International Rectifier - Application Training Guide  

NSDL National Science Digital Library

This website is International Rectifier's directory page to an application training guide for topics such as Basic Circuit Theory, Basic Semiconductor Theory, Device Cross Section, Mounting Techniques, and Typical Applications. Includes a glossary of acronyms.

2012-12-14

112

Synchronous Half-Wave Rectifier  

NASA Technical Reports Server (NTRS)

Synchronous rectifying circuit behaves like diode having unusually low voltage drop during forward-voltage half cycles. Circuit particularly useful in power supplies with potentials of 5 Vdc or less, where normal forward-voltage drops in ordinary diodes unacceptably large. Fabricated as monolithic assembly or as hybrid. Synchronous half-wave rectifier includes active circuits to attain low forward voltage drop and high rectification efficiency.

Rippel, Wally E.

1989-01-01

113

Brownian trail rectified  

SciTech Connect

The experiments described here indicate when one of Nature's best fractals -- the Brownian trail -- becomes nonfractal. In most ambient fluids, the trail of a Brownian particle is self-similar over many decades of length. For example, the trail of a submicron particle suspended in an ordinary liquid, recorded at equal time intervals, exhibits apparently discontinuous changes in velocity from macroscopic lengths down to molecular lengths: the trail is a random walk with no velocity memory'' from one step to the next. In ideal Brownian motion, the kinks in the trail persist to infinitesimal time intervals, i.e., it is a curve without tangents. Even in real Brownian motion in a liquid, the time interval must be shortened to {approximately}10{sup {minus}8}s before the velocity appears continuous. In sufficiently rarefied environments, this time resolution at which a Brownian trail is rectified from a curve without tangents to a smoothly varying trajectory is greatly lengthened, making it possible to study the kinetic regime by dynamic light scattering. Our recent experiments with particles in a plasma have demonstrated this capability. In this regime, the particle velocity persists over a finite step length'' allowing an analogy to an ideal gas with Maxwell-Boltzmann velocities; the particle mass could be obtained from equipartition. The crossover from ballistic flight to hydrodynamic diffusion was also seen. 8 refs., 1 fig.

Hurd, A.J.; Ho, P.

1989-01-01

114

Passivity-based control with dual lagrangian model of four-wire three-level three-phase NPC voltage-source rectifier  

Microsoft Academic Search

This paper presents the EL modeling of the four-wire 3-level 3-phase NPC voltage source rectifier (VSR). The load current of the four-wire 3-level 3-phase could be expressed in two forms: the load current involving the current of capacitor C1, and the load current involving the current of capacitor C2. So that two EL models will be obtained for four-wire 3-level

Majid Mehrasa; Saeed Lesan; S. N. H. Emeni; A. Sheikholeslami

2009-01-01

115

Multigigahertz voltage-controlled oscillators in advanced silicon bipolar technology  

Microsoft Academic Search

Relaxation-type monolithic silicon bipolar voltage-controlled oscillators (VCOs) with center frequencies ranging from 1.5 to 5 GHz are described. The maximum oscillating frequency achieved is 7.4 GHz. The VCOs dissipate about 70 mW from a 3.6-V supply, including the output buffer and voltage-to-current converter stages. Two types of on-chip timing capacitor structure and various configurations used in achieving these results are

Mehmet Soyuer; James D. Warnock

1992-01-01

116

A new ZVS-PWM active-clamping high power factor rectifier: analysis, design, and experimentation  

Microsoft Academic Search

In this paper a new single-phase rectifier is introduced, which features high power factor, regulation by conventional PWM technique, ZVS commutation and clamping action in both switches, and instantaneous average line current control. This rectifier consists of a front-end full-bridge diode rectifier followed by a ZVS-PWM, buck-boost active-clamping, boost converter. Experimental results are presented, taken from a laboratory prototype rated

Cliudio Manoel da Cunha Duarte; Ivo Barbi

1998-01-01

117

An evaluation system for experimental silicon and silicon carbide super gate turn off thyristors.  

PubMed

This paper describes the design and implementation of a small-scale pulsed power system specifically intended to evaluate the suitability of experimental silicon and silicon carbide high power Super Gate Turn Off thyristors for high action (500 A(2)?s and above) pulsed power applications where energy is extracted from a storage element in a rapid and controlled manner. To this end, six of each type of device was placed in a controlled three phase rectifier circuit which was in turn connected to an aircraft ground power motor-generator set and subjected to testing protocols with varying power levels, while parameters such as offset firing angle were varied. PMID:25085173

Bayne, Stephen; Lacouture, Shelby; Lawson, Kevin; Giesselmann, Michael; Scozzie, Charles J; O'Brien, Heather; Ogunniyi, Aderinto A

2014-07-01

118

An evaluation system for experimental silicon and silicon carbide super gate turn off thyristors  

NASA Astrophysics Data System (ADS)

This paper describes the design and implementation of a small-scale pulsed power system specifically intended to evaluate the suitability of experimental silicon and silicon carbide high power Super Gate Turn Off thyristors for high action (500 A2 s and above) pulsed power applications where energy is extracted from a storage element in a rapid and controlled manner. To this end, six of each type of device was placed in a controlled three phase rectifier circuit which was in turn connected to an aircraft ground power motor-generator set and subjected to testing protocols with varying power levels, while parameters such as offset firing angle were varied.

Bayne, Stephen; Lacouture, Shelby; Lawson, Kevin; Giesselmann, Michael; Scozzie, Charles J.; O'Brien, Heather; Ogunniyi, Aderinto A.

2014-07-01

119

MODELING OF HIGH-POWER-FACTOR RECTIFIERS BASED ON SWITCHING CONVERTERS  

E-print Network

Alter design. A line-frequency averaged model is presented for the purpose of designing the output flyback rectifier. 1 Introduction Nonlinear-carrier control (NLC) has recently been introduced for single-phase, high-power factor rectifiers [I, 21. The NLC control, with a block diagram shown in Fig. I, features

120

Humidity sensing properties of morphology-controlled ordered silicon nanopillar  

NASA Astrophysics Data System (ADS)

Ordered silicon nanopillar array (Si-NPA) was fabricated by nanosphere lithography. The size of silicon nanopillars can be easily controlled by an etching process. The period and density of nanopillar arrays are determined by the initial diameter of polystyrene (PS) spheres. It was studied as a sensing material to detect humidity. Room temperature current sensitivity of Si-NPA sensor was investigated at a relative humidity (RH) ranging from 50 to 70%. As a result, the measured current showed there was a significant increase at 70% RH. The response and recovery time was about 10 s and 15 s. These excellent sensing characteristics indicate that Si-NPA might be a practical sensing material.

Li, Wei; Hu, Mingyue; Ge, Pengpeng; Wang, Jing; Guo, YanYan

2014-10-01

121

Rectified-Nearest-Feature-Line-Segment 1 Rectified Nearest Feature Line Segment  

E-print Network

Rectified-Nearest-Feature-Line-Segment 1 Rectified Nearest Feature Line Segment for Pattern is built to represent each class. The proposed method, termed Rectified Nearest Feature Line Segment (RN the best performance. Keywords Pattern classification, nearest feature line, rectified nearest feature line

Washington at Seattle, University of

122

Quasisymmetry and rectifiability of quasispheres  

E-print Network

We obtain Dini conditions that guarantee that an asymptotically conformal quasisphere is rectifiable. In particular, we show that for any $\\epsilon>0$ integrability of $({\\rm ess}\\sup_{1-trectifiable. We also establish estimates for the weak quasisymmetry constant of a global $K$-quasiconformal map in neighborhoods with maximal dilatation close to 1.

Badger, Matthew; Rohde, Steffen; Toro, Tatiana

2012-01-01

123

UNIFORM MEASURES AND UNIFORM RECTIFIABILITY XAVIER TOLSA  

E-print Network

UNIFORM MEASURES AND UNIFORM RECTIFIABILITY XAVIER TOLSA Abstract. In this paper it is shown constant density condi- tion, then µ is uniformly rectifiable. This had already been proved by David to vanish out of a countably n-rectifiable subset of Rd. There are many other works in areas

Tolsa, Xavier

124

AVERAGE DENSITIES AND LINEAR RECTIFIABILITY OF MEASURES  

E-print Network

AVERAGE DENSITIES AND LINEAR RECTIFIABILITY OF MEASURES P. M ¨ ORTERS Abstract: We show that a measure on IR d is linearly rectifiable if and only if the lower 1­density is positive and finite regularity of the measure ¯ is intimately related to the behaviour of the densities. We say ¯ is ff­rectifiable

125

THE RECTIFIABILITY THRESHOLD IN ABELIAN GROUPS  

E-print Network

THE RECTIFIABILITY THRESHOLD IN ABELIAN GROUPS the smallest possible size of a non-t-rectifiable subset of G. Specifically, * *assuming that G is not t-isomorphic to a set of* * integers. 1.The smallest size of a non-rectifiable

Lev, Vsevolod F.

126

RECTIFIABILITY OF FLAT CHAINS Brian White  

E-print Network

RECTIFIABILITY OF FLAT CHAINS Brian White September 4, 1996; revised July 1, 1998 In memory) that a finite­mass flat chain over any coefficient group is rectifiable if and only if almost all of its 0­dimensional slices are rectifiable. This implies that every flat chain of finite mass and finite size

White, Brian

127

MASS TRANSPORT AND UNIFORM RECTIFIABILITY XAVIER TOLSA  

E-print Network

MASS TRANSPORT AND UNIFORM RECTIFIABILITY XAVIER TOLSA Abstract. In this paper we characterize the so called uniformly rectifiable sets of David and Semmes in terms of the Wasserstein distance W2 from,), where a = dµ d. 1. Introduction In this paper we characterize the so called uniformly rectifiable sets

Tolsa, Xavier

128

Automatic Recognition of Repeating Patterns in Rectified  

E-print Network

Automatic Recognition of Repeating Patterns in Rectified Facade Images DIPLOMARBEIT zur Erlangung Recognition of Repeating Patterns in Rectified Facade Images 16. Dezember 2009 #12;#12;Acknowledgments I would tasks, is able to robustly identify orthogonal repetitive patterns on rectified facade images even

129

Force commutated three level boost type rectifier  

Microsoft Academic Search

A new force commutated three level boost type rectifier is proposed in this paper. The rectifier has the characteristics of drawing nearly sinusoidal current from the utility with unity fundamental power factor. High reliability is possible due to its shoot-through free structure. A doubled DC bus voltage compared to a normal two-level rectifier is also possible because of the neutral

Yifan Zhao; Yue Li; Thomas A. Lipo

1995-01-01

130

PWM regenerative rectifiers: state of the art  

Microsoft Academic Search

New regulations impose more stringent limits on current harmonics injected by power converters that are achieved with pulsewidth-modulated (PWM) rectifiers. In addition, several applications demand the capability of power regeneration to the power supply. This work presents the state of the art in the field of regenerative rectifiers with reduced input harmonics and improved power factor. Regenerative rectifiers are able

Jos R. Rodrguez; Juan W. Dixon; Jos R. Espinoza; Jorge Pontt; Pablo Lezana

2005-01-01

131

Characterization of Nanostructured Silicon Membranes for Control of Molecular Transport  

NASA Astrophysics Data System (ADS)

Fabrication of nanoporous membranes for selective transport of molecular species requires precise engineering at the nanoscale. The membrane permeability can be tuned by controlling the physical structure and the surface chemistry of the pores. We use a combination of electron-beam and optical lithography, along with cryogenic deep reactive ion etching, to fabricate silicon membranes that are physically robust and have uniform pore sizes. Pore sizes are further reduced using plasma enhanced chemical vapor deposition and atomic layer deposition of silicon dioxide onto the membrane surfaces. Integrating nanoporous membranes within a microfluidic network provides a platform for tailoring molecular exchange between microchannels, independent of hydrodynamic effects. In enzymatic reactions, for example, tuning the pores size will allow smaller enzymatic substrates to traverse the membrane at controlled rates while larger enzymes remain spatially separated. Our results from membrane cross-sectioning using focused ion beam milling show that pore sizes can be controlled at dimensions below 10nm. Functional characterization was performed by quantitative fluorescence microscopy to observe the selective transport of molecular species of different sizes.

Srijanto, Bernadeta; Retterer, Scott; Fowlkes, Jason; Doktycz, Mitchel

2011-03-01

132

A novel variable frequency soft switching method for Flyback converter with synchronous rectifier  

Microsoft Academic Search

This paper proposes a variable frequency zero-voltage-switching (ZVS) control method for Flyback converter with synchronous rectifier. A lossless snubber capacitor is paralleled to the drain and source of primary switch to absorb the leakage inductance energy. The conventional passive clamp circuit with RCD is omitted, and no auxiliary switch or winding is needed. Synchronous rectifier is turned on additionally for

Xiucheng Huang; Weijing Du; Wei Yuan; Junming Zhang; Zhaoming Qian

2010-01-01

133

Regulation of a PWM rectifier in the unbalanced network state using a generalized model  

Microsoft Academic Search

This study concerns the modeling and control of a pulse-width-modulated (PWM) rectifier in the case of network variations. The aim is to limit and stabilize variations of DC output voltage and line currents in such circumstances. Network variations can result in costly damage to power converters and their loads but a power converter such as the PWM rectifier, using cascade

P. Rioual; H. Pouliquen; J.-P. Louis

1996-01-01

134

Physics of the frequency response of rectifying organic Schottky diodes  

NASA Astrophysics Data System (ADS)

The frequency response of unipolar organic Schottky diodes used in a rectifying circuit, such as an RFID tag, has been investigated in detail. The time dependent response of rectifying circuits has been simulated solving both the Drift Diffusion and Poisson equations to model the hole transport within the diode, coupled with time dependent circuit equations. Several approximations have also been discussed. It turns out that the cut off frequency of the rectifying circuit is indeed limited by the carrier time-of-flight and not by the diode equivalent capacitance. Simulations have also been confirmed by comparison with experiments, involving diodes with different mobilities and thicknesses. This work confirms that the 13.56 MHz frequency can be reached using polymer semiconductors, as already experimentally demonstrated in the literature, by an adequate control of the active layer thickness.

Altazin, Stphane; Clerc, Raphal; Gwoziecki, Romain; Verilhac, Jean-Marie; Boudinet, Damien; Pananakakis, Georges; Ghibaudo, Grard; Chartier, Isabelle; Coppard, Romain

2014-02-01

135

Detection of diffusion welding defects by thermal NDT of rectifier elements  

SciTech Connect

The possibility was investigated of applying thermal nondestructive testing to rectifying elements, because other methods of NDT (ultrasonic, radiational, electromagnetic, etc.) do not yield positive results in detecting flaws that are typical of diffusion welding. Among the findings, it is noted that optimum results are obtained when the rectifying element is heated on the side of silicon or tungsten, with recording of the radiation on the side of the silicon. The nature of the defects of diffusion welding is such that, no matter which method of heating is used, the defects look cooler on the thermogram. An automatic thermal flaw detector for scrapping defective rectifying elements by the method of thermal NDT is presently devised.

Bragina, L.A.; Vavilov, V.P.; Ivanov, A.I.; Korolkov, O.M.; Surzhenkov, G.N.; Khutorianskii, E.D.

1984-01-01

136

Three Phase Z-Source Rectifier  

Microsoft Academic Search

This paper makes the research on an impedance-source rectifier (abbreviated as Z-source rectifier), describes the operating principle, operating modes, and its concept and superiority. Analysis and simulation results show that the three-phase Z-source rectifier can buck-boost voltage by using the shoot-through state, which is harmful for the conventional VSR. It needs small dc-link inductor L and capacitor C, and makes

Xinping Ding; Zhaoming Qian; Yeyuan Xie; Zhengyu Lu

2005-01-01

137

UNIFORM RECTIFIABILITY AND HARMONIC MEASURE III: RIESZ TRANSFORM BOUNDS IMPLY UNIFORM RECTIFIABILITY OF  

E-print Network

UNIFORM RECTIFIABILITY AND HARMONIC MEASURE III: RIESZ TRANSFORM BOUNDS IMPLY UNIFORM RECTIFIABILITY OF BOUNDARIES OF 1-SIDED NTA DOMAINS STEVE HOFMANN, JOS´E MAR´IA MARTELL, AND SVITLANA MAYBORODA not exterior) Corkscrew condition. Then E is uniformly rectifiable. Contents 1. Introduction 1 1.1. Notation

Mayboroda, Svitlana

138

Genetic algorithm-based design of the active damping for an LCL-filter three-phase active rectifier  

Microsoft Academic Search

Active rectifiers\\/inverters are becoming used more and more often in regenerative systems and distributed power systems. Typically, the interface between the grid and rectifier is either an inductor or an LCL-filter. The use of an LCL-filter mitigates the switching ripple injected in the grid by a three-phase active rectifier. However, stability problems can arise in the current control loop. In

Marco Liserre; A. Dell'Aquila; F. Blaabjerg

2004-01-01

139

UNIFORM RECTIFIABILITY, CARLESON MEASURE ESTIMATES, AND APPROXIMATION OF HARMONIC FUNCTIONS  

E-print Network

UNIFORM RECTIFIABILITY, CARLESON MEASURE ESTIMATES, AND APPROXIMATION OF HARMONIC FUNCTIONS STEVE rectifiable set of dimension n. Then bounded harmonic functions in := Rn+1 \\ E satisfy Carleson measure25, 42B37. Key words and phrases. Carleson measures, -approximability, uniform rectifiability

Mayboroda, Svitlana

140

46 CFR 183.360 - Semiconductor rectifier systems.  

Code of Federal Regulations, 2013 CFR

...2013-10-01 2013-10-01 false Semiconductor rectifier systems. 183.360 Section...Distribution Systems 183.360 Semiconductor rectifier systems. (a) Each semiconductor rectifier system must have an...

2013-10-01

141

46 CFR 183.360 - Semiconductor rectifier systems.  

Code of Federal Regulations, 2010 CFR

...2010-10-01 2010-10-01 false Semiconductor rectifier systems. 183.360 Section...Distribution Systems 183.360 Semiconductor rectifier systems. (a) Each semiconductor rectifier system must have an...

2010-10-01

142

46 CFR 120.360 - Semiconductor rectifier systems.  

Code of Federal Regulations, 2012 CFR

...2012-10-01 2012-10-01 false Semiconductor rectifier systems. 120.360 Section...Distribution Systems 120.360 Semiconductor rectifier systems. (a) Each semiconductor rectifier system must have an...

2012-10-01

143

46 CFR 120.360 - Semiconductor rectifier systems.  

Code of Federal Regulations, 2010 CFR

...2010-10-01 2010-10-01 false Semiconductor rectifier systems. 120.360 Section...Distribution Systems 120.360 Semiconductor rectifier systems. (a) Each semiconductor rectifier system must have an...

2010-10-01

144

46 CFR 120.360 - Semiconductor rectifier systems.  

Code of Federal Regulations, 2013 CFR

...2013-10-01 2013-10-01 false Semiconductor rectifier systems. 120.360 Section...Distribution Systems 120.360 Semiconductor rectifier systems. (a) Each semiconductor rectifier system must have an...

2013-10-01

145

46 CFR 183.360 - Semiconductor rectifier systems.  

Code of Federal Regulations, 2011 CFR

...2011-10-01 2011-10-01 false Semiconductor rectifier systems. 183.360 Section...Distribution Systems 183.360 Semiconductor rectifier systems. (a) Each semiconductor rectifier system must have an...

2011-10-01

146

46 CFR 120.360 - Semiconductor rectifier systems.  

Code of Federal Regulations, 2011 CFR

...2011-10-01 2011-10-01 false Semiconductor rectifier systems. 120.360 Section...Distribution Systems 120.360 Semiconductor rectifier systems. (a) Each semiconductor rectifier system must have an...

2011-10-01

147

46 CFR 183.360 - Semiconductor rectifier systems.  

Code of Federal Regulations, 2012 CFR

...2012-10-01 2012-10-01 false Semiconductor rectifier systems. 183.360 Section...Distribution Systems 183.360 Semiconductor rectifier systems. (a) Each semiconductor rectifier system must have an...

2012-10-01

148

A SILICON RETINA WITH CONTROLLABLE WINNER-TAKE-ALL PROPERTIES Shih-Chii Liu  

E-print Network

A SILICON RETINA WITH CONTROLLABLE WINNER-TAKE-ALL PROPERTIES Shih-Chii Liu Institute network of Lazzaro together with spatial coupling forms the current-mode silicon retina of Boahen and Andreou (1992). This retina models the center- surround processing performed in biological retinas to en

Liu, Shih-Chii

149

Long-term, controlled release of the HIV microbicide TMC120 from silicone elastomer vaginal rings  

Microsoft Academic Search

Objectives: The feasibility of providing prolonged and controlled release of the experimental non- nucleoside reverse transcriptase inhibitor TMC120 from a silicone vaginal ring in quantities sufficient to maintain a vaginal concentration offering protection against heterosexual HIV transmission was investigated. Methods: Core-type, silicone elastomer vaginal rings containing TMC120 were manufactured, and in vitro release studies performed under sink conditions. The experimental

R. Karl Malcolm; A. David Woolfson; Clare F. Toner; Ryan J. Morrow; Stephen D. McCullagh

2005-01-01

150

The inward rectifier potassium channel family  

Microsoft Academic Search

Recent cloning of a family of genes encoding inwardly rectifying K+ channels has provided the opportunity to explain some venerable problems in membrane biology. An expanding number of novel inwardly rectifying K+ channel clones has revealed multiple channel subfamilies that have specialized roles in cell function. The molecular determinants of inward rectification have been largely elucidated with the discovery of

Craig A Doupnik; Norman Davidson; Henry A Lester

1995-01-01

151

46 CFR 129.360 - Semiconductor-rectifier systems.  

Code of Federal Regulations, 2010 CFR

... Semiconductor-rectifier systems. 129.360 Section 129... OFFSHORE SUPPLY VESSELS ELECTRICAL INSTALLATIONS Power Sources and Distribution Systems 129.360 Semiconductor-rectifier systems. (a) Each...

2010-10-01

152

Noise-compensating pulses for electrostatically controlled silicon spin qubits  

NASA Astrophysics Data System (ADS)

We study the performance of supcodea family of dynamically correcting pulses designed to cancel simultaneously both Overhauser and charge noise for singlet-triplet spin qubitsadapted to silicon devices with electrostatic control. We consider both natural Si and isotope-enriched Si systems, and in each case we investigate the behavior of individual gates under static noise and perform randomized benchmarking to obtain the average gate error under realistic 1/f noise. We find that in most cases supcode pulses offer roughly an order of magnitude reduction in gate error, and especially in the case of isotope-enriched Si, supcode yields gate operations of very high fidelity. We also develop a version of supcode that cancels the charge noise only, "?J-supcode," which is particularly beneficial for isotope-enriched Si devices where charge noise dominates Overhauser noise, offering a level of error reduction comparable to the original supcode while yielding gate times that are 30%-50% shorter. Our results show that the supcode noise-compensating pulses provide a fast, simple, and effective approach to error suppression, bringing gate errors well below the quantum error correction threshold in principle.

Wang, Xin; Calderon-Vargas, F. A.; Rana, Muhed S.; Kestner, J. P.; Barnes, Edwin; Das Sarma, S.

2014-10-01

153

Controlling carbon nanotube photoluminescence using silicon microring resonators.  

PubMed

We report on coupling between semiconducting single-wall carbon nanotubes (s-SWNT) photoluminescence and silicon microring resonators. Polyfluorene extracted s-SWNT deposited on such resonators exhibit sharp emission peaks, due to interaction with the cavity modes of the microring resonators. Ring resonators with radius of 5 ?m and 10 ?m were used, reaching quality factors up to 4000 in emission. These are among the highest values reported for carbon nanotubes coupled with an integrated cavity on silicon platform, which open up the possibility to build s-SWNT based efficient light source on silicon. PMID:24787283

Noury, Adrien; Le Roux, Xavier; Vivien, Laurent; Izard, Nicolas

2014-05-30

154

Control of carbon balance in a silicon smelting furnace  

DOEpatents

The present invention is a process for the carbothermic reduction of silicon dioxide to form elemental silicon. Carbon balance of the process is assessed by measuring the amount of carbon monoxide evolved in offgas exiting the furnace. A ratio of the amount of carbon monoxide evolved and the amount of silicon dioxide added to the furnace is determined. Based on this ratio, the carbon balance of the furnace can be determined and carbon feed can be adjusted to maintain the furnace in carbon balance.

Dosaj, V.D.; Haines, C.M.; May, J.B.; Oleson, J.D.

1992-12-29

155

Geometry control of recrystallized silicon wafers for solar applications  

E-print Network

The cost of manufacturing crystalline silicon wafers for use in solar cells can be reduced by eliminating the waste streams caused by sawing ingots into individual wafers. Professor Emanuel Sachs has developed a new method ...

Ruggiero, Christopher W

2009-01-01

156

Regulation of oceanic silicon and carbon preservation by temperature control on bacteria.  

PubMed

We demonstrated in laboratory experiments that temperature control of marine bacteria action on diatoms strongly influences the coupling of biogenic silica and organic carbon preservation. Low temperature intensified the selective regeneration of organic matter by marine bacteria as the silicon:carbon preservation ratio gradually increased from approximately 1 at 33 degrees C to approximately 6 at -1.8 degrees C. Temperature control of bacteria-mediated selective preservation of silicon versus carbon should help to interpret and model the variable coupling of silicon and carbon sinking fluxes and the spatial patterns of opal accumulation in oceanic systems with different temperature regimes. PMID:12471255

Bidle, Kay D; Manganelli, Maura; Azam, Farooq

2002-12-01

157

Distant Cytosolic Residues Mediate a Two-way Molecular Switch That Controls the Modulation of Inwardly Rectifying Potassium (Kir) Channels by Cholesterol and Phosphatidylinositol 4,5-Bisphosphate (PI(4,5)P2)*  

PubMed Central

Inwardly rectifying potassium (Kir) channels play an important role in setting the resting membrane potential and modulating membrane excitability. An emerging feature of several Kir channels is that they are regulated by cholesterol. However, the mechanism by which cholesterol affects channel function is unclear. Here we show that mutations of two distant Kir2.1 cytosolic residues, Leu-222 and Asn-251, form a two-way molecular switch that controls channel modulation by cholesterol and affects critical hydrogen bonding. Notably, these two residues are linked by a residue chain that continues from Asn-251 to connect adjacent subunits. Furthermore, our data indicate that the same switch also regulates the sensitivity of the channels to phosphatidylinositol 4,5-bisphosphate, a phosphoinositide that is required for activation of Kir channels. Thus, although cholesterol and phosphatidylinositol 4,5-bisphosphate do not interact with the same region of Kir2.1, these different modulators induce a common gating pathway of the channel. PMID:22995912

Rosenhouse-Dantsker, Avia; Noskov, Sergei; Han, Huazhi; Adney, Scott K.; Tang, Qiong-Yao; Rodriguez-Menchaca, Aldo A.; Kowalsky, Gregory B.; Petrou, Vasileios I.; Osborn, Catherine V.; Logothetis, Diomedes E.; Levitan, Irena

2012-01-01

158

A unity power factor three phase PWM SCR rectifier for high power applications in the metal industry  

Microsoft Academic Search

A new thyristor current source rectifier that achieves unity power factor, low current THD and DC bus current and voltage control is presented. The rectifier is suitable for high power applications such as induction heating and DC arc furnaces. It combines a traditional six-pulse thyristor bridge and a DC chopper that together solve power quality problems such as poor power

Ian Wallace; Ashish Bendre; Jonathan Nord; Giri Venkataramanan

2001-01-01

159

A current-type PWM rectifier with active damping function  

Microsoft Academic Search

A new control method for current-type pulse-width modulation (PWM) rectifiers which can provide active damping function is presented. This damping function is effective only on the harmonic components of AC input current selectively. Thus steady-state waveform distortion and transient oscillation of the input current are reduced by the active damping effects. The active damping function can be realized by feedback

Yukihiko Sato; Teruo Kataoka

1996-01-01

160

A new ZVS-PWM unity power factor rectifier with reduced conduction losses  

Microsoft Academic Search

This paper introduces a new single-phase high power factor rectifier, which features regulation by conventional PWM, soft commutation and instantaneous average line current control. Furthermore, thanks to the use of a single converter, instead of the conventional configuration composed of a four-diode front-end rectifier followed by a boost converter, a significant reduction in the conduction losses is achieved. A prototype

Alexandre Ferrari de Souza; Ivo Barbi

1995-01-01

161

Geometry enhanced asymmetric rectifying tunneling diodes Kwangsik Choi,a  

E-print Network

Geometry enhanced asymmetric rectifying tunneling diodes Kwangsik Choi,a Geunmin Ryu, Filiz MHz. Superior rectifying performance of a Ni ATD is observed due to smaller band-edge offsets al.4 Here, the rectified dc voltage Vrect presented to and the rectified current Irect driven through

Dagenais, Mario

162

The inward rectifier in a model of corticotroph electrical activity  

E-print Network

The inward rectifier in a model of corticotroph electrical activity Paul R. Shorten , A. Bruce, Canterbury, New Zealand. #12;#12;The inward rectifier in a model of corticotroph electrical activity Paul R an inwardly rectifying K+ current. In this paper we investigate a role of the inwardly rectifying K+ current

Reale, Marco

163

RECTIFIERS AND THE LOCAL LANGLANDS CORRESPONDENCE: THE UNRAMIFIED CASE  

E-print Network

RECTIFIERS AND THE LOCAL LANGLANDS CORRESPONDENCE: THE UNRAMIFIED CASE MOSHE ADRIAN AND DAVID ROE Abstract. We generalize the rectifier of Bushnell and Henniart, which occurs in the local Langlands's rectifier to groups other than GLn(K). In particular, we define rectifiers for unramified min- isotropic

Roe, David

164

Variational Learning for Rectified Factor Markus Harva1  

E-print Network

Variational Learning for Rectified Factor Analysis Markus Harva1 Adaptive Informatics Research, such as the exponential, the rectified Gaussian, or mixtures of these. The rectified Gaussian distribu- tion is particularly convenient, as it is conjugate to the Gaussian likelihood and hence it yields a rectified Gaussian

Ruan, Jianhua

165

A Variational Bayesian Method for Rectified Factor Markus Harva  

E-print Network

A Variational Bayesian Method for Rectified Factor Analysis Markus Harva Neural Networks Research, such as the exponential, the rectified Gaussian, or mixtures of these. The rectified Gaussian distribution is particularly convenient, as it is conjugate to the Gaussian likelihood and hence it yields a rectified Gaussian posterior

Kaban, Ata

166

Intersection of continua and rectifiable curves  

E-print Network

We prove that for any non-degenerate continuum $K \\subseteq \\mathbb{R}^d$ there exists a rectifiable curve such that its intersection with $K$ has Hausdorff dimension 1. This answers a question of B. Kirchheim.

Balka, Richrd

2012-01-01

167

The control of oscillation mode in silicon microbeams using silicon nitride anchor  

NASA Astrophysics Data System (ADS)

We designed and fabricated gravimetric sensors composed of silicon (Si) microbeams surrounded by silicon nitride (SiN) anchors. The oscillation properties of the fabricated devices show that a single oscillation mode originating from quasi-one-dimensional microbeams appears at an applied alternating electric field, which motion is well matched to the theoretical predictions and is much different from the dimensionally mixed oscillation modes in normal non-anchored devices. In addition, in order to elucidate the possibilities of the devices for mass sensing applications, we measured the frequency shift as a function of mass loading in a self-assembled monolayer of 3-aminopropyltrimethoxysilane and Au nanoparticles. The resulting limit of detection was 1.05 10-18 g/Hz, which is an extremely high value for micro electromechanical system gravimetric sensors relative to the normal ones.

Baek, In-Bok; Lee, Bong Kuk; Kim, Yarkyeon; Ahn, Chang-Geun; Kim, Young Jun; Yoon, Yong Sun; Jang, Won Ik; Kim, Hakseong; Lee, Sang Wook; Lee, Seongjae; Yu, Han Young

2014-09-01

168

High-Voltage Diamond Vertical Schottky rectifiers  

Microsoft Academic Search

We have designed, simulated and experimentally demonstrated high-voltage vertical diamond Schottky rectifiers. The rectifiers were fabricated on free-standing homo-epi films with remarkably low p-type doping using a lift-off process. Theoretical calculations have been performed to determine the thickness and doping concentration of the drift region. Devices with 20mum epi layer have been shown to block 3.7kV and conduct 0.6 A\\/cm2

W. Huang; T. P. Chow; J. Yang; J. E. Butler

2005-01-01

169

Comparison of Thyristor-Rectifier with Hybrid Filter and Chopper-Rectifier for High-Power, High-Current Application  

E-print Network

Comparison of Thyristor-Rectifier with Hybrid Filter and Chopper- Rectifier for High-Power, High Solutions GmbH, Belecke-Warstein, Germany Abstract This paper presents a comparison of two rectifier of application is a multi-pulse thyristor rectifier. Active or passive filters are added to the thyristor

Paderborn, Universität

170

DQ-transformation approach for modelling and stability analysis of AC-DC power system with controlled PWM rectifier and constant power loads  

Microsoft Academic Search

In this paper a technique for analysing aircraft frequency wild power systems with constant power loads is developed and demonstrated. Power electronic based loads often behave as constant power loads, especially when feeding machine or actuator drives under current and speed control. The constant power (CP) loads can affect the stability of the power system. The problem is a particular

K.-N. Areerak; S. V. Bozhko; G. M. Asher; D. W. P. Thomas

2008-01-01

171

Process to produce silicon carbide fibers using a controlled concentration of boron oxide vapor  

NASA Technical Reports Server (NTRS)

A process for producing polycrystalline silicon carbide by heating an amorphous ceramic fiber that contains silicon and carbon in an environment containing boron oxide vapor. The boron oxide vapor is produced in situ by the reaction of a boron containing material such as boron carbide and an oxidizing agent such as carbon dioxide, and the amount of boron oxide vapor can be controlled by varying the amount and rate of addition of the oxidizing agent.

Barnard, Thomas Duncan (Inventor); Lipowitz, Jonathan (Inventor); Nguyen, Kimmai Thi (Inventor)

2001-01-01

172

Process to produce silicon carbide fibers using a controlled concentration of boron oxide vapor  

NASA Technical Reports Server (NTRS)

A process for producing polycrystalline silicon carbide includes heating an amorphous ceramic fiber that contains silicon and carbon in an environment containing boron oxide vapor. The boron oxide vapor is produced in situ by the reaction of a boron containing material such as boron carbide and an oxidizing agent such as carbon dioxide, and the amount of boron oxide vapor can be controlled by varying the amount and rate of addition of the oxidizing agent.

Barnard, Thomas Duncan (Inventor); Lipowitz, Jonathan (Inventor); Nguyen, Kimmai Thi (Inventor)

2000-01-01

173

Amorphous silicon Schottky barrier solar cells incorporating a thin insulating layer and a thin doped layer  

DOEpatents

Amorphous silicon Schottky barrier solar cells which incorporate a thin insulating layer and a thin doped layer adjacent to the junction forming metal layer exhibit increased open circuit voltages compared to standard rectifying junction metal devices, i.e., Schottky barrier devices, and rectifying junction metal insulating silicon devices, i.e., MIS devices.

Carlson, David E. (Yardley, PA)

1980-01-01

174

RF sputtering for controlling dihydride and monohydride bond densities in amorphous silicon hydride  

DOEpatents

A process is described for controlling the dihydride and monohydride bond densities in hydrogenated amorphous silicone produced by reactive rf sputtering of an amorphous silicon target. There is provided a chamber with an amorphous silicon target and a substrate therein with the substrate and the target positioned such that when rf power is applied to the target the substrate is in contact with the sputtering plasma produced thereby. Hydrogen and argon are fed to the chamber and the pressure is reduced in the chamber to a value sufficient to maintain a sputtering plasma therein, and then rf power is applied to the silicon target to provide a power density in the range of from about 7 watts per square inch to about 22 watts per square inch to sputter an amorphous solicone hydride onto the substrate, the dihydride bond density decreasing with an increase in the rf power density. Substantially pure monohydride films may be produced.

Jeffery, F.R.; Shanks, H.R.

1980-08-26

175

Thermal system design and modeling of meniscus controlled silicon growth process for solar applications  

NASA Astrophysics Data System (ADS)

The direct conversion of solar radiation to electricity by photovoltaics has a number of significant advantages as an electricity generator. That is, solar photovoltaic conversion systems tap an inexhaustible resource which is free of charge and available anywhere in the world. Roofing tile photovoltaic generation, for example, saves excess thermal heat and preserves the local heat balance. This means that a considerable reduction of thermal pollution in densely populated city areas can be attained. A semiconductor can only convert photons with the energy of the band gap with good efficiency. It is known that silicon is not at the maximum efficiency but relatively close to it. There are several main parts for the photovoltaic materials, which include, single- and poly-crystalline silicon, ribbon silicon, crystalline thin-film silicon, amorphous silicon, copper indium diselenide and related compounds, cadmium telluride, et al. In this dissertation, we focus on melt growth of the single- and poly-crystalline silicon manufactured by Czochralski (Cz) crystal growth process, and ribbon silicon produced by the edge-defined film-fed growth (EFG) process. These two methods are the most commonly used techniques for growing photovoltaic semiconductors. For each crystal growth process, we introduce the growth mechanism, growth system design, general application, and progress in the numerical simulation. Simulation results are shown for both Czochralski and EFG systems including temperature distribution of the growth system, velocity field inside the silicon melt and electromagnetic field for the EFG growth system. Magnetic field is applied on Cz system to reduce the melt convection inside crucible and this has been simulated in our numerical model. Parametric studies are performed through numerical and analytical models to investigate the relationship between heater power levels and solidification interface movement and shape. An inverse problem control scheme is developed to control the solidification interface of Cz system by adjusting heater powers. For the EFG system, parametric studies are performed to discuss the effect of several growth parameters including window opening size, argon gas flow rate and growth thermal environment on the temperature distribution, silicon tube thickness and pulling rate. Two local models are developed and integrated with the global model to investigate the detailed transport phenomena in a small region around the solidification interface including silicon crystal, silicon melt, free surface, liquid-solid interface and graphite die design. Different convection forms are taken into consideration.

Wang, Chenlei

176

Circuit topologies for PWM boost rectifiers operated from 1-phase and 3-phase AC supplies and using either single or split DC rail voltage outputs  

Microsoft Academic Search

This paper provides a survey of PWM boost rectifier circuit topologies for controlling a nonisolated DC-rail voltage whilst drawing supply currents at a unity fundamental power factor and with a low total harmonic distortion. Rectifier-leg topologies are classified by the number of switches and by the PWM waveforms generated. Complete rectifier circuit topologies are described for operation off 1-phase and

John C. Salmon

1995-01-01

177

Advanced process control and novel test methods for PVD silicon and elastomeric silicone coatings utilized on ion implant disks, heatsinks and selected platens  

SciTech Connect

Coatings play multiple key roles in the proper functioning of mature and current ion implanters. Batch and serial implanters require strategic control of elemental and particulate contamination which often includes scrutiny of the silicon surface coatings encountering direct beam contact. Elastomeric Silicone Coatings must accommodate wafer loading and unloading as well as direct backside contact during implant plus must maintain rigid elemental and particulate specifications. The semiconductor industry has had a significant and continuous effort to obtain ultra-pure silicon coatings with sustained process performance and long life. Low particles and reduced elemental levels for silicon coatings are a major requirement for process engineers, OEM manufacturers, and second source suppliers. Relevant data will be presented. Some emphasis and detail will be placed on the structure and characteristics of a relatively new PVD Silicon Coating process that is very dense and homogeneous. Wear rate under typical ion beam test conditions will be discussed. The PVD Silicon Coating that will be presented here is used on disk shields, wafer handling fingers/fences, exclusion zones of heat sinks, beam dumps and other beamline components. Older, legacy implanters can now provide extended process capability using this new generation PVD silicon - even on implanter systems that were shipped long before the advent of silicon coating for contamination control. Low particles and reduced elemental levels are critical performance criteria for the silicone elastomers used on disk heatsinks and serial implanter platens. Novel evaluation techniques and custom engineered tools are used to investigate the surface interaction characteristics of multiple Elastomeric Silicone Coatings currently in use by the industry - specifically, friction and perpendicular stiction. These parameters are presented as methods to investigate the critical wafer load and unload function. Unique tools and test methods have been developed that deliver accurate and repeatable data, which will be described.

Springer, J.; Allen, B.; Wriggins, W.; Kuzbyt, R.; Sinclair, R. [Core Systems, 1050 Kifer Road Sunnyvale, CA 94086 (United States); FI Silicon, 1050 Kifer Road Sunnyvale, CA 94086 (United States); Core Systems, 1050 Kifer Road Sunnyvale, CA 94086 (United States)

2012-11-06

178

Flow restrictor silicon membrane microvalve actuated by optically controlled paraffin phase transition  

NASA Astrophysics Data System (ADS)

Restrictor valves allow proportional control of fluid flow but are rarely integrated in microfluidic systems. In this study, an optically actuated silicon membrane restrictor microvalve is demonstrated. Its actuation is based on the phase transition of paraffin, using a paraffin wax mixed with a suitable concentration of optically absorbing nanographite particles. Backing up the membrane with oil (the melted paraffin) allows for a compliant yet strong contact to the valve seat, which enables handling of high pressures. At flow rates up to 30?L min-1 and at a pressure of 2 bars, the valve can successfully be closed and control the flow level by restriction. The use of this paraffin composite as an adhesive layer sandwiched between the silicon valve and glass eases fabrication. This type of restrictor valve is best suited for high pressure, low volume flow silicon-based nanofluidic systems.

Kolari, K.; Havia, T.; Stuns, I.; Hjort, K.

2014-08-01

179

A Novel Buck-Boost Z-Source Rectifier  

Microsoft Academic Search

This paper presents a novel buck\\/boost Z-Source rectifier, in which an impedance network is employed to couple the rectifier main circuit to the load, thus it provides unique features that cannot be obtained in a traditional full-bridge rectifier. The Z-source rectifier can access buck or boost function without using two-stage power conversion, so it overcomes the limitations of the traditional

Yeyuan Xie; Zhaoming Qian; Xinping Ding; Fangzheng Peng

2006-01-01

180

Southern Ocean control of silicon stable isotope distribution in the deep Atlantic Ocean  

E-print Network

Southern Ocean control of silicon stable isotope distribution in the deep Atlantic Ocean Gregory F distribution in the deep Atlantic Ocean from Denmark Strait to Drake Passage, documenting strong meridional sources of deep and bottom waters in the Atlantic Ocean: waters of North Atlantic and Nordic origin carry

Paris-Sud XI, Université de

181

Test and quality control of double-sided silicon microstrip sensors for the ALICE experiment  

Microsoft Academic Search

Production of 1800 double-sided silicon microstrip sensors, designed to equip the two outermost layers of the ALICE Inner Tracking System, has started in the second half of 2002. Results of sensor testing and quality control performed at INFN, Trieste on the pre-series and on the first series production batches is reported.

I. Rachevskaia; L. Bosisio; S. Potin; O. Starodubtsev

2004-01-01

182

Hydrogenated amorphous silicon formation by flux control and hydrogen effects on the growth mechanism  

Microsoft Academic Search

The composition of particle flux to deposit hydrogenated amorphous silicon films in a glow discharge is controlled by a combined electrostatic-magnetic deflection technique. As a result, the films are formed firstly without hydrogen ion flux, secondly by neutral flux only, and thirdly by all species fluxes. Comparison of these films reveals the significant role of hydrogen in the surface reactions.

H. Toyoda; H. Sugai; K. Kato; A. Yoshida; T. Okuda

1986-01-01

183

Controlling polarization of vertical-cavity surface-emitting lasers using amorphous silicon subwavelength transmission gratings  

E-print Network

device for use in integrated optoelectronic cir- cuits. In applications where polarization sensitive compo- nents are widely used, such as magneto-optic recording and coherent detection systemsControlling polarization of vertical-cavity surface-emitting lasers using amorphous silicon

184

A novel integrated current doubler rectifier  

Microsoft Academic Search

This paper presents an innovative current doubler rectifier, which integrates all the magnetic components into a single core and minimizes the number of high current windings. Compared to the conventional approach, the proposed integrated magnetic structure features reduced core loss, smaller core size, and reduced AC conduction losses, all while still reducing winding losses. The new rectification circuit can be

Peng Xu; Qiaoqiao Wu; Pit-Leong Wong; Fred C. Lee

2000-01-01

185

Carbon nanocone: A promising thermal rectifier  

Microsoft Academic Search

With molecular dynamics simulations, we demonstrate very obvious thermal rectification in large temperature range from 200 to 400 K in nanocone. We also observe that the rectification of nanocone does not depend on the length very sensitively, which is in stark contrast with the nanotube thermal rectifier in which the rectification decreases dramatically as the length increases. Our work demonstrates

Nuo Yang; Gang Zhang; Baowen Li

2008-01-01

186

High-voltage diamond Schottky rectifiers  

Microsoft Academic Search

In this paper, we simulate and fabricate diamond Schottky rectifiers. The growth rate of pure diamond single crystal epitaxial is from 0.5 up to 100?m\\/hr with boron doping concentration around 11014 cm-3 to 11016 cm-3. A \\

W. Huang; T. P. Chow; J. Yang; J. E. Butler

2004-01-01

187

Input Impedance Modeling of Multipulse Rectifiers by Harmonic Linearization  

Microsoft Academic Search

Multipulse rectifiers are used in large industrial drives, aircraft, electric ships, and other systems, where limits on harmonic currents prohibit the use of conventional three-phase, six-pulse rectifiers. The large power rating of these rectifiers and the dynamic nature of the loads often necessitate the study of their dynamic interactions with the source, which can lead to system stability and power

Jian Sun; Zhonghui Bing; Kamiar J. Karimi

2009-01-01

188

Physics of the Frequency Response of Rectifying Organic Schottky Diodes  

E-print Network

1 Physics of the Frequency Response of Rectifying Organic Schottky Diodes a,b Stéphane Altazin*, c.clerc@institutoptique.fr) Keywords: Organic Schottky diode, RFID Tag, rectifying circuit, Frequency, time dependent response, modeling) #12;2 Abstract The frequency response of unipolar organic Schottky diodes used in a rectifying

Paris-Sud XI, Université de

189

THE RIESZ TRANSFORM, RECTIFIABILITY, AND REMOVABILITY FOR LIPSCHITZ HARMONIC  

E-print Network

THE RIESZ TRANSFORM, RECTIFIABILITY, AND REMOVABILITY FOR LIPSCHITZ HARMONIC FUNCTIONS FEDOR) is bounded in L2 (Hn E), then E is n-rectifiable. From this result we deduce that a compact set E Rn+1 transform is bounded in L2 with respect to Hn E, then E is n-rectifiable. Combined with results from [Vo

Tolsa, Xavier

190

Rectified Surface Mosaics Robert E. Carroll Steven M. Seitz  

E-print Network

Rectified Surface Mosaics Robert E. Carroll Steven M. Seitz University of Washington Abstract We reference plane in the scene. In this case, the images can be rectified to align with the physi- cal]. In this paper, we generalize the approach of plane rec- tification to allow distortion-free rectified mosaics

Washington at Seattle, University of

191

Rectified Catadioptric Stereo Sensors Joshua Gluckman and Shree K. Nayar  

E-print Network

Rectified Catadioptric Stereo Sensors Joshua Gluckman and Shree K. Nayar Department of Computer mirrors that must be satisfied to obtain rectified stereo images with a single camera. Then we discuss systems, whether catadioptric or two- camera, require images to be rectified prior to stereo matching

Nayar, Shree K.

192

Average densities, tangent measures and rectifiability Peter Morters  

E-print Network

Average densities, tangent measures and rectifiability Peter M¨orters Universit¨at Kaiserslautern. The measure ¯ is called ff­rectifiable if ff is an integer and ¯ is absolutely continuous with respect to ff that ¯ is linearly rectifiable. An important problem in geometric measure theory is to find local criteria

193

BLOW-UP IN NON HOMOGENEOUS LIE GROUPS AND RECTIFIABILITY  

E-print Network

BLOW-UP IN NON HOMOGENEOUS LIE GROUPS AND RECTIFIABILITY G. CITTI, M. MANFREDINI Abstract. In this paper we extend the De Giorgi notion of rectifiability of surfaces in non homogeneous Lie groups dimension Q of the space, see (6), and give the definition of a rectifiable set as a set S Rn , which can

Citti, Giovanna

194

Project: Three phase rectifier with low current Student: David Chernya  

E-print Network

Project: Three phase rectifier with low current harmonics Student: David Chernya Year: 2005 industry and, chemical and electrochemical plants. Temporary rectifiers use "static" diode bridges of this project is to design and build a high power, three-phase rectifier with low input current harmonics

195

A new class of (Hk , 1)-rectifiable subsets of metric  

E-print Network

A new class of (Hk , 1)-rectifiable subsets of metric spaces R. Ghezzi , F. Jean September 14, 2011 the class of 1-rectifiable sets does not contain smooth non-horizontal curves; therefore a new definition of rectifiable sets including non-horizontal curves is needed. This is why we introduce in any metric space a new

196

Brief Communication Constitutively Active G-Protein-Gated Inwardly Rectifying  

E-print Network

Brief Communication Constitutively Active G-Protein-Gated Inwardly Rectifying K Channels. Activities of these inwardly rectifying K channels were inhibited by Ba2 (200 M) and tertiapin (10 nM), both of which are believed to block G-protein-coupled inwardly rectifying K (GIRK) channels. Intracellularly

Johnston, Daniel

197

Pattern Classification using Rectified Nearest Feature Line Segment  

E-print Network

Pattern Classification using Rectified Nearest Feature Line Segment Hao Du and Yan Qiu Chen, Rectified Nearest Feature Line Segment (RNFLS), is proposed that addresses both of the above- mentioned, the "territory" of each sample point and each class is defined, and we obtain Rectified Nearest Feature Line

Washington at Seattle, University of

198

A new class of (Hk , 1)-rectifiable subsets of metric  

E-print Network

A new class of (Hk , 1)-rectifiable subsets of metric spaces R. Ghezzi , F. Jean May 24, 2012 the class of 1-rectifiable sets does not contain smooth non-horizontal curves; therefore a new definition of rectifiable sets including non-horizontal curves is needed. This is why we introduce in any metric space a new

Paris-Sud XI, Université de

199

Controlling Dopant Profiles in Hyperdoped Silicon by Modifying Dopant Evaporation Rates During Pulsed Laser Melting  

SciTech Connect

We describe a method to control the sub-surface dopant profile in 'hyperdoped' silicon fabricated by ion implantation and pulsed laser melting. Dipping silicon ion implanted with sulfur into hydrofluoric acid prior to nanosecond pulsed laser melting leads to a tenfold increase in the rate of sulfur evaporation from the surface of the melt. This results in an 80% reduction of the near-surface dopant concentration, effectively embedding the hyperdoped region in a layer up to 180 nm beneath the surface. This method should facilitate the development of blocked impurity band devices.

Recht, D.; Sullivan, J. T.; Reedy, R.; Buonassisi, T.; Aziz, M. J.

2012-03-12

200

On-chip silicon photonic wavelength control of optical fiber lasers.  

PubMed

Tunable silicon microring filters are used to demonstrate CMOS-compatible on-chip wavelength control of Er(+) doped fiber-lasers. An onchip Ni-Cr micro-heater consuming up to 20 mW is capable of tuning the Si microring filter by 1.3 nm with a lasing linewidths narrower than 0.02 nm. This approach enables arbitrary multiple wavelength generation on a silicon chip. Possible applications include on-chip and chip-to-chip dense-wavelength division multiplexed communications and sensor interrogation. PMID:18825205

Wang, Xuan; Liu, Tao; de Almeida, Vilson R; Panepucci, Roberto R

2008-09-29

201

Functional conversion between A-type and delayed rectifier K+ channels by membrane lipids.  

PubMed

Voltage-gated potassium (Kv) channels control action potential repolarization, interspike membrane potential, and action potential frequency in excitable cells. It is thought that the combinatorial association between distinct alpha and beta subunits determines whether Kv channels function as non-inactivating delayed rectifiers or as rapidly inactivating A-type channels. We show that membrane lipids can convert A-type channels into delayed rectifiers and vice versa. Phosphoinositides remove N-type inactivation from A-type channels by immobilizing the inactivation domains. Conversely, arachidonic acid and its amide anandamide endow delayed rectifiers with rapid voltage-dependent inactivation. The bidirectional control of Kv channel gating by lipids may provide a mechanism for the dynamic regulation of electrical signaling in the nervous system. PMID:15031437

Oliver, Dominik; Lien, Cheng-Chang; Soom, Malle; Baukrowitz, Thomas; Jonas, Peter; Fakler, Bernd

2004-04-01

202

Controlled growth of oriented amorphous silicon nanowires via a solidliquidsolid (SLS) mechanism  

Microsoft Academic Search

Highly oriented amorphous silicon nanowires (a-SiNWs ) were grown on Si (111). The length and diameter of oriented SiNWs are almost uniform, which are 1?m and 25nm, respectively. Different from the well-known vaporliquidsolid (VLS) for conventional whisker growth, it was found that growth of the a-SiNWs was controlled by a solidliquidsolid mechanism (SLS). This synthesis method is simple and controllable.

D. P Yu; Y. J Xing; Q. L Hang; H. F Yan; J Xu; Z. H Xi; S. Q Feng

2001-01-01

203

Controlling the transmission of ultrahigh frequency bulk acoustic waves in silicon by 45 mirrors.  

PubMed

In this paper, we present a feasible microsystem in which the direction of localized ultrahigh frequency (?1GHz) bulk acoustic wave can be controlled in a silicon wafer. Deep etching technology on the silicon wafer makes it possible to achieve high aspect ratio etching patterns which can be used to control bulk acoustic wave to transmit in the directions parallel to the surface of the silicon wafer. Passive 45 mirror planes obtained by wet chemical etching were employed to reflect the bulk acoustic wave. Zinc oxide (ZnO) thin film transducers were deposited by radio frequency sputtering with a thickness of about 1?m on the other side of the wafer, which act as emitter/receptor after aligned with the mirrors. Two opponent vertical mirrors were inserted between the 45 mirrors to guide the transmission of the acoustic waves. The propagation of the bulk acoustic wave was studied with simulations and the characterization of S(21) scattering parameters, indicating that the mirrors were efficient to guide bulk acoustic waves in the silicon wafer. PMID:21295322

Wang, Shengxiang; Gao, Jiaming; Carlier, Julien; Campistron, Pierre; NDieguene, Assane; Guo, Shishang; Matar, Olivier Bou; Dorothee, Debavelaere-Callens; Nongaillard, Bertrand

2011-07-01

204

A unity-power-factor three-phase PWM SCR rectifier for high-power applications in the metal industry  

Microsoft Academic Search

A new thyristor current-source rectifier that achieves unity power factor, low-current total harmonic distortion (THD), and DC-bus current and voltage control is presented. The rectifier is suitable for high-power applications such as induction heating and DC arc furnaces. It combines a traditional six-pulse thyristor bridge and a DC chopper that together solve power quality problems such as poor power factor

Ian Wallace; Ashish Bendre; Jonathan P. Nord; Giri Venkataramanan

2002-01-01

205

Measurement and Control of In-plane Surface Chemistry at the Silicon/Silicon Dioxide Interface  

NASA Astrophysics Data System (ADS)

In-plane directional control of surface chemistry during interface formation can lead to new opportunities regarding device structures and applications. Control of this type requires techniques that can probe and hence provide feedback on the chemical reactivity of bonds not only in specific directions but also in real time. In this thesis work, I demonstrate both control and measurement of the oxidation of H-terminated Si(111). The nonlinear optical tool of Second-Harmonic-Generation (SHG) is used to show that Si oxidation in air is a two-stage process where the H of the "up" bonds of the outermost Si layer is replaced by OH, followed by O insertion into the "back" bonds. Detailed information about both stages is revealed by investigating the effect of uniaxial strain and carrier concentration on this chemical reaction. It is shown that even small amounts of strain manipulate the reaction kinetics of surface bonds significantly, with tensile strain enhancing oxidation and compressive strain retarding it. This dramatic change suggests a strain-driven charge transfer mechanism between Si--H up bonds and Si--Si back bonds in the outer layer of Si atoms. Data on differently doped samples reveal that high concentrations of electrons increase the chemical reactivity of the outer-layer Si--Si back bonds relative to the Si--H up bonds while high concentrations of holes cause a greater increase in the reactivity of the Si--H up bonds than that of the Si--Si back bonds. However, the thicknesses of the natural oxides of all samples follow the same path and stabilize near 1 nm at room temperature, regardless of the chemical kinetics of the different bonds, as determined by spectroscopic ellipsometry. Real-time measurement during SHG experiments is achieved by analyzing SHG anisotropy data with the anisotropic bond-charge model of nonlinear optics where peaks in the SHG spectrum are correlated with the near alignment of bonds to the direction of the excitation field.

Gokce, Bilal

206

Three phase six-switch PWM buck rectifier with power factor improvement  

NASA Astrophysics Data System (ADS)

Conventional Phase Controlled Rectifier injects low order current harmonics into the AC mains. Large size filtering components are required to attenuate these harmonics. In this paper, three phase six-switch PWM buck rectifier is presented which operates at nearly unity power factor and provides variable output voltage. Small size energy storing components are required depending upon switching frequency. MATLAB simulation is performed and modified Sinusoidal Pulse Width Modulation (SPWM) switching technique is used in 3kW prototype converter to demonstrate low input current THD, nearly unity displacement factor, well regulated output voltage and reduced switching losses compared to conventional SPWM.

Zafarullah Khan, M.; Mohsin Naveed, M.; Akbar Hussain, D. M.

2013-06-01

207

Six Unimolecular Rectifiers and What Lies Ahead  

NASA Astrophysics Data System (ADS)

Six unimolecular rectifiers are discussed: ?-hexadecylquinolinium tricyanoquinodimethanide, 1, and two thioacetyl derivatives of 1, namely (Z)-?-cyano-?-[N-tetradecylthioacetylquinolin-4-ylium)-4-styryl-dicyanomethanide, 2, and (Z)-?-cyano-?-[N-hexadecylthioacetylquinolin-4-ylium)-4-styryl-dicyanomethanide, 3, and three other rectifiers of very different structure: 2,6-di[dibutylaminophenylvinyl]-1-butylpyridinium iodide, 4, dimethylanilino-aza[C60]-fullerene, 5, and fullerene-bis-[4-diphenylamino-4?-(N-ethyl-N-2??-ethyl)amino-1,4-diphenyl-1,3-butadiene] malonate, 6. Monolayers of these molecules exhibit asymmetric electrical conductivity between Au or Al electrodes. We also suggest approaches towards one-molecule electronic devices, useful for the ultimate reduction in circuit sizes.

Metzger, Robert M.

208

Optimal locomotion of mechanical rectifier systems  

NASA Astrophysics Data System (ADS)

Vehicles utilizing animal locomotion mechanisms may possess increased performance parameters and the ability to overcome more difficult terrain than conventional wheel or propeller driven vehicles. The essential mechanism underlying animal locomotion can be viewed as mechanical rectification that converts periodic body movements to thrust force through interactions with the environment. This dissertation defines a general class of mechanical rectifiers as multi-body systems equipped with such thrust generation mechanisms. A general model is developed from the Euler-Lagrange equation and simplified by assuming small body oscillations around a given nominal posture. The model reveals that the rectifying dynamics can be captured by a bilinear (but not linear) term of body shape variables. An optimal gait problem is formulated for the bilinear rectifier model as a minimization of a quadratic cost function over the set of periodic functions subject to a constraint on the average locomotion velocity. We prove that a globally optimal solution is given by a harmonic gait that can be found by generalized eigenvalue computation with a line search over cycle frequencies. We verify the solution method through case studies of a two dimensional chain of links for which snake-like undulations and jellyfish-like flapping gaits are found to be optimal, and obtain analytical insights into determinants of optimal gaits from a simple disk-mass rectifier system. Lastly, we develop a dynamic model for batoid swimming featuring a 6 degree-of-freedom main body (position and orientation), with independent wing deformation (described as the motion of many discrete points in the body-fixed coordinate frame), and calculate various gaits. Multiple wing shapes and optimality criteria are considered, such as the maximum thrust to deflection ratio or minimum input power, and the resulting gaits are compared.

Blair, Justin T.

209

Stability improvements of an LCL-filter based three-phase active rectifier  

Microsoft Academic Search

Three-phase active rectifiers guarantee sinusoidal input currents and controllable dc voltage at the price of a high switching frequency ripple that can disturb and reduce efficiency of other EMI sensitive equipment connected to the grid. This problem could be solved choosing a high value for the ac inductors making them expensive and bulky. Moreover the dynamic of the system becomes

Marco Liserre; Antonio Dell' Aquila; Frede Blaabjerg

2002-01-01

210

Strong voltage-dependent inward rectification of inward rectifier K + channels is caused by intracellular spermine  

Microsoft Academic Search

Inward rectifier K+ channels mediate the K+ conductance at resting potential in many types of cell. Since these K+ channels do not pass outward currents (inward rectification) when the cell membrane is depolarized beyond a trigger threshold, they play an important role in controlling excitability. Both a highly voltage-dependent block by intracellular Mg2+ and an endogenous gating process are presently

B Fakler; U Brndle; E Glowatzki; S Weidemann; H.-P Zenner; J. P Ruppersberg

1995-01-01

211

A high performance single phase AC to DC rectifier with input power factor correction  

Microsoft Academic Search

A high performance single phase AC to DC rectifier with input power factor correction is proposed. The proposed approach has many advantages which include fewer semiconductor components, simplified control, high performance features and satisfaction of IEC 555 harmonic current standards. Simulation and experimental results obtained on a laboratory prototype are discussed

P. N. Enjeti; R. Martinez

1993-01-01

212

Quantum entanglement and spin control in silicon nanocrystal.  

PubMed

Selective coherence control and electrically mediated exchange coupling of single electron spin between triplet and singlet states using numerically derived optimal control of proton pulses is demonstrated. We obtained spatial confinement below size of the Bohr radius for proton spin chain FWHM. Precise manipulation of individual spins and polarization of electron spin states are analyzed via proton induced emission and controlled population of energy shells in pure (29)Si nanocrystal. Entangled quantum states of channeled proton trajectories are mapped in transverse and angular phase space of (29)Si <100> axial channel alignment in order to avoid transversal excitations. Proton density and proton energy as impact parameter functions are characterized in single particle density matrix via discretization of diagonal and nearest off-diagonal elements. We combined high field and low densities (1 MeV/92 nm) to create inseparable quantum state by superimposing the hyperpolarizationed proton spin chain with electron spin of (29)Si. Quantum discretization of density of states (DOS) was performed by the Monte Carlo simulation method using numerical solutions of proton equations of motion. Distribution of gaussian coherent states is obtained by continuous modulation of individual spin phase and amplitude. Obtained results allow precise engineering and faithful mapping of spin states. This would provide the effective quantum key distribution (QKD) and transmission of quantum information over remote distances between quantum memory centers for scalable quantum communication network. Furthermore, obtained results give insights in application of channeled protons subatomic microscopy as a complete versatile scanning-probe system capable of both quantum engineering of charged particle states and characterization of quantum states below diffraction limit linear and in-depth resolution.PACS NUMBERS: 03.65.Ud, 03.67.Bg, 61.85.+p, 67.30.hj. PMID:23028884

Berec, Vesna

2012-01-01

213

Quantum entanglement and spin control in silicon nanocrystal  

E-print Network

Selective coherence control and electrically mediated exchange coupling of single electron spin between triplet and singlet states using numerically derived optimal control of proton pulses is demonstrated. We obtained spatial confinement below size of the Bohr radius for proton spin chain FWHM. Precise manipulation of individual spins and polarization of electron spin states are analyzed via proton induced emission and controlled population of energy shells in pure 29Si nanocrystal. Entangled quantum states of channeled proton trajectories are mapped in transverse and angular phase space of 29Si axial channel alignment in order to avoid transversal excitations. Proton density and proton energy as impact parameter functions are characterized in single particle density matrix via discretization of diagonal and nearest off-diagonal elements. We combined high field and low densities (1 MeV/92 nm) to create inseparable quantum state by superimposing the hyperpolarizationed proton spin chain with electron spin of 29Si. Quantum discretization of density of states (DOS) was performed by the Monte Carlo simulation method using numerical solutions of proton equations of motion. Distribution of gaussian coherent states is obtained by continuous modulation of individual spin phase and amplitude. Obtained results allow precise engineering and faithful mapping of spin states. This would provide the effective quantum key distribution (QKD) and transmission of quantum information over remote distances between quantum memory centers for scalable quantum communication network. Furthermore, obtained results give insights in application of channeled protons subatomic microscopy as a complete versatile scanning-probe system capable of both quantum engineering of charged particle states and characterization of quantum states below diffraction limit linear and in-depth resolution.

Vesna Berec

2012-10-16

214

Resistive switching with self-rectifying behavior in Cu/SiOx/Si structure fabricated by plasma-oxidation  

NASA Astrophysics Data System (ADS)

We report a resistive switching memory structure based on silicon wafers by employing both materials and processing fully compatible with complementary metal-oxide semiconductor technology. A SiOx nanolayer was fabricated by direct plasma-oxidation of silicon wafers at room-temperature. Resistive switching behaviors were investigated on both p- and n-Si wafers, whereas self-rectifying effect was obtained in the Cu/SiOx/n-Si structure at low-resistance state. The self-rectifying effect was explained by formation of the Schottky barrier between the as-formed Cu filament and the n-Si. These results suggest a convenient and cost-efficient technical-route to develop high-density resistive switching memory for nowadays Si-based semiconductor industry.

Tang, G. S.; Zeng, F.; Chen, C.; Liu, H. Y.; Gao, S.; Li, S. Z.; Song, C.; Wang, G. Y.; Pan, F.

2013-06-01

215

Uniform rectifiability and harmonic measure I: Uniform rectifiability implies Poisson kernels in $L^p$  

E-print Network

We present a higher dimensional, scale-invariant version of a classical theorem of F. and M. Riesz. More precisely, we establish scale invariant absolute continuity of harmonic measure with respect to surface measure, along with higher integrability of the Poisson kernel, for a domain $\\Omega\\subset \\re^{n+1},\\, n\\geq 2$, with a uniformly rectifiable boundary, which satisfies the Harnack Chain condition plus an interior (but not exterior) corkscrew condition. In a companion paper to this one \\cite{HMU}, we also establish a converse, in which we deduce uniform rectifiability of the boundary, assuming scale invariant $L^q$ bounds, with $q>1$, on the Poisson kernel.

Hofmann, Steve

2012-01-01

216

Boundedness of the square function and rectifiability Svitlana Mayboroda a  

E-print Network

Boundedness of the square function and rectifiability Svitlana Mayboroda a , Alexander Volberg b a to Hausdorff measure Hn (n is interger) on a set E implies that E is rectifiable. 1. Introduction For a Borel(y), Rs , µ(x) := Rs µ(x) - Rs µ(x), (2) where x Rd , > > 0. One says that the set E Rd is n-rectifiable

Mayboroda, Svitlana

217

Efficient design of rectifying antennas for low power detection  

Microsoft Academic Search

This article is dedicated to the design of rectifying antenna for wireless energy transfer at 2.45 GHz in the special case of low input power (typically <-10 dBm). As the rectifiers present an important non-linear behavior with such power levels, specific design guidelines must be respected in order to optimize the structure. Different rectifying circuits have been studied and their

Vlad Marian; Cyrille Menudier; Marc Thevenot; Christian Vollaire; Jacques Verdier; Bruno Allard

2011-01-01

218

Controlled line shaped electron beam for silicon zone melting recrystallization on float glass substrates  

NASA Astrophysics Data System (ADS)

A line shaped electron beam system for the zone melting recrystallization (ZMR) of thick silicon films on float glass substrates is described. The low thermal stability of the glass requires a rapid regulated zone heating. The electron beam system allows the ZMR in a continuous scan without pulsing. The setup consists of the tungsten wire with a Pierce reflector as line cathode and the moving substrate as anode. A negative voltage applied on the reflectors limits the electron emission and provides the necessary control. The melt energy for optimized processing decreases with an increase of the velocity. The beam profiles and penetration depth of the electrons is discussed. Homogenous polycrystalline silicon areas of several 10cm2 are achieved on a tungsten coated borosilicate float glass for the intended use as solar cell absorber.

Gromball, F.; Groth, C.; Mller, J.

2005-06-01

219

FAST TRACK COMMUNICATION: Nanocrystalline silicon film growth morphology control through RF waveform tailoring  

NASA Astrophysics Data System (ADS)

We demonstrate the application of RF waveform tailoring to generate an electrical asymmetry in a capacitively coupled plasma-enhanced chemical vapour deposition system, and its use to control the growth mode of hydrogenated amorphous and nanocrystalline silicon thin films deposited at low temperature (150 C). A dramatic shift in the dc bias potential at the powered electrode is observed when simply inverting the voltage waveform from 'peaks' to 'troughs', indicating an asymmetric distribution of the sheath voltage. By enhancing or suppressing the ion bombardment energy at the substrate (situated on the grounded electrode), the growth of thin silicon films can be switched between amorphous and nanocrystalline modes, as observed using in situ spectroscopic ellipsometry. The effect is observed at pressures sufficiently low that the collisional reduction in average ion bombardment energy is not sufficient to allow nanocrystalline growth (<100 mTorr).

Johnson, Erik V.; Verbeke, Thomas; Vanel, Jean-Charles; Booth, Jean-Paul

2010-10-01

220

Growth of silicon nanowires of controlled diameters by electrodeposition in ionic liquid at room temperature.  

PubMed

Silicon nanowires were fabricated for the first time by electrochemical template synthesis at room temperature. This innovative, cheap, and simple process consists of electroreduction of Si ions using a nonaqueous solvent and insulating nanoporous membranes with average pore diameters from 400 to 15 nm which fix the nanowires diameters. Characterization techniques such as scanning and transmission electron microscopies, infrared absorption measurements, X-ray diffraction experiments, energy dispersive X-ray, and Raman spectrometries show that the as-deposited silicon nanowires are amorphous, composed of pure Si and homogeneous in sizes with average diameters and lengths well matching with the nanopores' diameters and the thicknesses of the membranes. Thanks to annealing treatments, it is possible to crystallize the Si nanowires, demonstrating the potentiality for this innovative electrochemical process to obtain a wide range of Si nanowires with well controlled diameters and lengths. PMID:18788792

Mallet, J; Molinari, M; Martineau, F; Delavoie, F; Fricoteaux, P; Troyon, M

2008-10-01

221

Controlling the Er content of porous silicon using the doping current intensity  

PubMed Central

The results of an investigation on the Er doping of porous silicon are presented. Electrochemical impedance spectroscopy, optical reflectivity, and spatially resolved energy dispersive spectroscopy (EDS) coupled to scanning electron microscopy measurements were used to investigate on the transient during the first stages of constant current Er doping. Depending on the applied current intensity, the voltage transient displays two very different behaviors, signature of two different chemical processes. The measurements show that, for equal transferred charge and identical porous silicon (PSi) layers, the applied current intensity also influences the final Er content. An interpretative model is proposed in order to describe the two distinct chemical processes. The results can be useful for a better control over the doping process. PACS 81.05.Rm; 82.45.Rr PMID:25024691

2014-01-01

222

Conditional Control of Donor Nuclear Spins in Silicon Using Stark Shifts  

NASA Astrophysics Data System (ADS)

Electric fields can be used to tune donor spins in silicon using the Stark shift, whereby the donor electron wave function is displaced by an electric field, modifying the hyperfine coupling between the electron spin and the donor nuclear spin. We present a technique based on dynamic decoupling of the electron spin to accurately determine the Stark shift, and illustrate this using antimony donors in isotopically purified silicon-28. We then demonstrate two different methods to use a dc electric field combined with an applied resonant radio-frequency (rf) field to conditionally control donor nuclear spins. The first method combines an electric-field induced conditional phase gate with standard rf pulses, and the second one simply detunes the spins off resonance. Finally, we consider different strategies to reduce the effect of electric field inhomogeneities and obtain above 90% process fidelities.

Wolfowicz, Gary; Urdampilleta, Matias; Thewalt, Mike L. W.; Riemann, Helge; Abrosimov, Nikolai V.; Becker, Peter; Pohl, Hans-Joachim; Morton, John J. L.

2014-10-01

223

Gate-controlled-diodes in silicon-on-sapphire: A computer simulation  

NASA Technical Reports Server (NTRS)

The computer simulation of the electrical behavior of a Gate-Controlled Diode (GCD) fabricated in Silicon-On-Sapphire (SOS) was described. A procedure for determining lifetime profiles from capacitance and reverse current measurements on the GCD was established. Chapter 1 discusses the SOS structure and points out the need of lifetime profiles to assist in device design for GCD's and bipolar transistors. Chapter 2 presents the one-dimensional analytical formula for electrostatic analysis of the SOS-GCD which are useful for data interpretation and setting boundary conditions on a simplified two-dimensional analysis. Chapter 3 gives the results of a two-dimensional analysis which treats the field as one-dimensional until the silicon film is depleted and the field penetrates the sapphire substrate. Chapter 4 describes a more complete two-dimensional model and gives results of programs implementing the model.

Gassaway, J. D.

1974-01-01

224

RECTIFIABLE AND FLAT G CHAINS IN A METRIC SPACE THIERRY DE PAUW AND ROBERT HARDT  

E-print Network

RECTIFIABLE AND FLAT G CHAINS IN A METRIC SPACE THIERRY DE PAUW AND ROBERT HARDT Contents 1 Rectifiable G Chains in X 5 3.1. Rectifiable Sets in a Metric Space 5 3.2. 0 Dimensional Rectifiable G Chains.6. Two Alternate Characterizations of Rectifiable G Chains 11 3.7. Slicing 13 3.8. Relations Between

De Pauw, Thierry - Institut de Mathématiques de Jussieu, Université Paris 7

225

EE 321 Diodes 2 Fall 2008 Diodes, Part 2 --Rectifier Circuits  

E-print Network

EE 321 Diodes 2 Fall 2008 EE321 Lab Diodes, Part 2 -- Rectifier Circuits The purpose of this laboratory is to investigate the use of diodes in rectifier circuits and to build precision rectifiers. Half Wave Rectifiers 1. Construct the simple half-wave rectifier shown in Figure 1 (use a 1N4001 diode

Wedeward, Kevin

226

46 CFR 129.360 - Semiconductor-rectifier systems.  

Code of Federal Regulations, 2011 CFR

...360 Shipping COAST GUARD, DEPARTMENT OF HOMELAND SECURITY (CONTINUED) OFFSHORE SUPPLY VESSELS ELECTRICAL INSTALLATIONS Power Sources and Distribution Systems 129.360 Semiconductor-rectifier systems. (a) Each...

2011-10-01

227

46 CFR 129.360 - Semiconductor-rectifier systems.  

Code of Federal Regulations, 2012 CFR

...360 Shipping COAST GUARD, DEPARTMENT OF HOMELAND SECURITY (CONTINUED) OFFSHORE SUPPLY VESSELS ELECTRICAL INSTALLATIONS Power Sources and Distribution Systems 129.360 Semiconductor-rectifier systems. (a) Each...

2012-10-01

228

46 CFR 129.360 - Semiconductor-rectifier systems.  

Code of Federal Regulations, 2013 CFR

...360 Shipping COAST GUARD, DEPARTMENT OF HOMELAND SECURITY (CONTINUED) OFFSHORE SUPPLY VESSELS ELECTRICAL INSTALLATIONS Power Sources and Distribution Systems 129.360 Semiconductor-rectifier systems. (a) Each...

2013-10-01

229

Serum proteins and paraproteins in women with silicone implants and connective tissue disease: a case-control study  

PubMed Central

Prior studies have suggested abnormalities of serum proteins, including paraproteins, in women with silicone implants but did not control for the presence of connective-tissue disease (CTD). This retrospective casecontrol study, performed in tertiary-care academic centers, assessed possible alterations of serum proteins, including paraproteins, in such a population. Seventy-four women with silicone implants who subsequently developed CTD, and 74 age-matched and CTD-matched women without silicone implants, were assessed in the primary study; other groups were used for additional comparisons. Routine serum protein determinations and high-sensitivity protein electrophoresis and immunofixation electrophoresis were performed for detection of paraproteins. Women with silicone implants, either with or without CTD, had significantly lower serum total protein and ?1-globulin, ?2-globulin, ?-globulin, ?-globulin, and IgG levels compared with those without silicone implants. There was no significant difference, however, in the frequency of paraproteinemia between women with silicone implants and CTD (9.5%) and age-matched and CTD-matched women without silicone implants (5.4%) (odds ratio, 1.82; 95% confidence interval, 0.516.45). Paraprotein isotypes were similar in the two groups, and the clinical characteristics of the 13 women with paraproteinemia were comparable with an independent population of 10 women with silicone breast implants, CTD, and previously diagnosed monoclonal gammopathies. In summary, this first comprehensive study of serum proteins in women with silicone implants and CTD found no substantially increased risk of monoclonal gammopathy. Women with silicone implants, however, had unexpectedly low serum globulin and immunoglobulin levels, with or without the subsequent development of CTD. The causes and clinical implications of these findings require further investigation. PMID:17875216

Csako, Gyorgy; Costello, Rene; Shamim, Ejaz A; O'Hanlon, Terrance P; Tran, Anthony; Clauw, Daniel J; Williams, H James; Miller, Frederick W

2007-01-01

230

Alternating to Direct: Rectifying Alternating Current  

NSDL National Science Digital Library

The Materials Science and Technology Teacher's Workshop (MAST) provides this activity for classes learning about diodes and electrical currents. The laboratory illustrates how diodes can be used to rectify alternating current. It uses a galvanometer to determine the direction of current flow when an AC or DC current is applied to the circuit containing a diode in series with a resistor and a galvanometer.The lesson includes step by step directions for the experiment.The activity should require about 20-30 minutes of class time to complete. Discussion questions and teacher notes are included.

2012-12-03

231

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

SciTech Connect

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

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

2002-04-01

232

A CMOS microdisplay with integrated controller utilizing improved silicon hot carrier luminescent light sources  

NASA Astrophysics Data System (ADS)

Microdisplay technology, the miniaturization and integration of small displays for various applications, is predominantly based on OLED and LCoS technologies. Silicon light emission from hot carrier electroluminescence has been shown to emit light visibly perceptible without the aid of any additional intensification, although the electrical to optical conversion efficiency is not as high as the technologies mentioned above. For some applications, this drawback may be traded off against the major cost advantage and superior integration opportunities offered by CMOS microdisplays using integrated silicon light sources. This work introduces an improved version of our previously published microdisplay by making use of new efficiency enhanced CMOS light emitting structures and an increased display resolution. Silicon hot carrier luminescence is often created when reverse biased pn-junctions enter the breakdown regime where impact ionization results in carrier transport across the junction. Avalanche breakdown is typically unwanted in modern CMOS processes. Design rules and process design are generally tailored to prevent breakdown, while the voltages associated with breakdown are too high to directly interact with the rest of the CMOS standard library. This work shows that it is possible to lower the operating voltage of CMOS light sources without compromising the optical output power. This results in more efficient light sources with improved interaction with other standard library components. This work proves that it is possible to create a reasonably high resolution microdisplay while integrating the active matrix controller and drivers on the same integrated circuit die without additional modifications, in a standard CMOS process.

Venter, Petrus J.; Alberts, Antonie C.; du Plessis, Monuko; Joubert, Trudi-Heleen; Goosen, Marius E.; Janse van Rensburg, Christo; Rademeyer, Pieter; Faur, Nicolaas M.

2013-03-01

233

High voltage GaN Schottky rectifiers  

SciTech Connect

Mesa and planar GaN Schottky diode rectifiers with reverse breakdown voltages (V{sub RB}) up to 550 and >2,000V, respectively have been fabricated. The on-state resistance, R{sub ON}, was 6 m{Omega}{center_dot}cm{sup 2} and 0.8{Omega} cm{sup 2}, respectively, producing figure-of-merit values for (V{sub RB}){sup 2}/R{sub ON} in the range 5-48 MW{center_dot}cm{sup {minus}2}. At low biases the reverse leakage current was proportional to the size of the rectifying contact perimeter, while at high biases the current was proportional to the area of this contact. These results suggest that at low reverse biases, the leakage is dominated by the surface component, while at higher biases the bulk component dominates. On-stage voltages were 3.5 V for the 550 V diodes and {ge}15 for the 2kV diodes. Reverse recovery times were <0.2 {mu}s for devices switched from a forward current density of {approximately}500 A{center_dot}cm{sup {minus}2} to a reverse bias of 100 V.

Dang, G.T.; Zhang, A.P.; Ren, F. [and others] [and others

2000-04-01

234

High Voltage GaN Schottky Rectifiers  

SciTech Connect

Mesa and planar GaN Schottky diode rectifiers with reverse breakdown voltages (V{sub RB}) up to 550V and >2000V, respectively, have been fabricated. The on-state resistance, R{sub ON}, was 6m{Omega}{center_dot} cm{sup 2} and 0.8{Omega}cm{sup 2}, respectively, producing figure-of-merit values for (V{sub RB}){sup 2}/R{sub ON} in the range 5-48 MW{center_dot}cm{sup -2}. At low biases the reverse leakage current was proportional to the size of the rectifying contact perimeter, while at high biases the current was proportional to the area of this contact. These results suggest that at low reverse biases, the leakage is dominated by the surface component, while at higher biases the bulk component dominates. On-state voltages were 3.5V for the 550V diodes and {ge}15 for the 2kV diodes. Reverse recovery times were <0.2{micro}sec for devices switched from a forward current density of {approx}500A{center_dot}cm{sup -2} to a reverse bias of 100V.

CAO,X.A.; CHO,H.; CHU,S.N.G.; CHUO,C.-C.; CHYI,J.-I.; DANG,G.T.; HAN,JUNG; LEE,C.-M.; PEARTON,S.J.; REN,F.; WILSON,R.G.; ZHANG,A.P.

1999-10-25

235

Rectified Linear Units Improve Restricted Boltzmann Machines Vinod Nair vnair@cs.toronto.edu  

E-print Network

Rectified Linear Units Improve Restricted Boltzmann Machines Vinod Nair vnair, rectified lin- ear units. Compared with binary units, these units learn features that are better for object units, rectified linear units preserve information about relative in- tensities as information travels

Hinton, Geoffrey E.

236

Power Factor Correctors for Rectifiers Chavdar Korsemov, Zdravko Nikolov, Stefan Koynov  

E-print Network

99 Power Factor Correctors for Rectifiers Chavdar Korsemov, Zdravko Nikolov, Stefan Koynov for the consumed harmonics from the mains and which the conventional rectifiers fail to satisfy. During the last the rectifier current purely harmonic. Also

Borissova, Daniela

237

Improved quality control of silicon wafers using novel off-line air pocket image analysis  

NASA Astrophysics Data System (ADS)

Air pockets (APK) occur randomly in Czochralski (Cz) grown silicon (Si) crystals and may become included in wafers after slicing and polishing. Previously the only APK of interest were those that intersected the front surface of the wafer and therefore directly impacted device yield. However mobile and other electronics have placed new demands on wafers to be internally APK-free for reasons of thermal management and packaging yield. We present a novel, recently patented, APK image processing technique and demonstrate the use of that technique, off-line, to improve quality control during wafer manufacturing.

Valley, John F.; Sanna, M. Cristina

2014-08-01

238

Hydrogenated amorphous silicon formation by flux control and hydrogen effects on the growth mechanism  

NASA Astrophysics Data System (ADS)

The composition of particle flux to deposit hydrogenated amorphous silicon films in a glow discharge is controlled by a combined electrostatic-magnetic deflection technique. As a result, the films are formed firstly without hydrogen ion flux, secondly by neutral flux only, and thirdly by all species fluxes. Comparison of these films reveals the significant role of hydrogen in the surface reactions. Hydrogen breaks the Si-Si bond, decreases the sticking probability of the Si atom, and replaces the SiH bond by a SiH2 bond to increase the hydrogen content of the films.

Toyoda, H.; Sugai, H.; Kato, K.; Yoshida, A.; Okuda, T.

1986-06-01

239

Self-organizing microstructures orientation control in femtosecond laser patterning on silicon surface.  

PubMed

Self-organizing rippled microstructures are induced on silicon surface by linearly polarized femtosecond laser pulses. At a near threshold fluence, it is observed that ripple orientation is co-determined by the laser polarization direction and laser scanning parameters (scanning direction and scanning speed) in surface patterning process. Under fixed laser polarization, the ripple orientation can be controlled to rotate by about 40 through changing laser scanning parameters. In addition, it is also observed that the ripple morphology is sensitive to the laser scanning direction, and it is an optimal choice to obtain ordered ripple structures when the angle between laser scanning and laser polarization is less than 45. PMID:25090485

Liu, Pengjun; Jiang, Lan; Hu, Jie; Zhang, Shuai; Lu, Yongfeng

2014-07-14

240

High power factor rectifier with reduced conduction and commutation losses  

Microsoft Academic Search

This paper presents a high power factor rectifier with reduced conduction and commutation losses for telecommunication applications. The reduced conduction losses are obtained through the use of a single converter, instead of the conventional configuration, composed of a four-diode front-end rectifier followed by a boost converter. A nondissipative snubber is responsible for the reduction in the commutation losses. A prototype

Alexandre Ferrari de Souza; Ivo Barbi

1999-01-01

241

Controlling the spectrum of photons generated on a silicon nanophotonic chip.  

PubMed

Directly modulated semiconductor lasers are widely used, compact light sources in optical communications. Semiconductors can also be used to generate nonclassical light; in fact, CMOS-compatible silicon chips can be used to generate pairs of single photons at room temperature. Unlike the classical laser, the photon-pair source requires control over a two-dimensional joint spectral intensity (JSI) and it is not possible to process the photons separately, as this could destroy the entanglement. Here we design a photon-pair source, consisting of planar lightwave components fabricated using CMOS-compatible lithography in silicon, which has the capability to vary the JSI. By controlling either the optical pump wavelength, or the temperature of the chip, we demonstrate the ability to select different JSIs, with a large variation in the Schmidt number. Such control can benefit high-dimensional communications where detector-timing constraints can be relaxed by realizing a large Schmidt number in a small frequency range. PMID:25410792

Kumar, Ranjeet; Ong, Jun Rong; Savanier, Marc; Mookherjea, Shayan

2014-01-01

242

A space vector-based rectifier regulator for AC\\/DC\\/AC converters  

Microsoft Academic Search

A voltage-sourced rectifier control scheme for use with AC\\/DC\\/AC variable speed drives is presented. A control scheme is derived that directly calculates the duration of time spent on the zero state and on each switching state adjacent to the reference vector, over a constant switching interval, in order to drive the line current vector to the reference vector. In addition,

Thomas G. Habetler

1993-01-01

243

A new single-phase single-switch PWM three-level high power factor rectifier with separate regulation of output capacitors voltage  

Microsoft Academic Search

In this paper, a new control scheme is proposed for the new single-phase single-switch three-level rectifier to supply two different load with different voltages and draw sinusoidal line current with low THD. The adopted rectifier consists of a diode bridge, a power switch and two blocking diodes. Low cost, simple structure and convenient control and three level voltage are the

Seied Nima Hoseini Eimeni; Ahmad Radan; Majid Mehrasa

2009-01-01

244

A Novel Cl Inward-Rectifying Current in the Plasma Membrane of the Calcifying Marine Phytoplankton  

E-print Network

A Novel Cl Inward-Rectifying Current in the Plasma Membrane of the Calcifying Marine Phytoplankton rectifier that tightly regulates membrane potential. Membrane depolarization gave rise to nonselective

Taylor, Alison

245

Spatial properties of rectified cosine Gaussian beams  

NASA Astrophysics Data System (ADS)

The cosine Gaussian beam (CGB) resulting from the coherent coaxial superposition of two Gaussian beams having the same width W and opposite radii of curvature R and - R is a ringed beam characterized by an M2 factor which can be very high, and adjustable by changing R. According to the paper by Hasnaoui et al(2011 Opt. Commun.284 1331-4) we expect that the CGB after rectification by a binary diffractive optical element could be a good candidate for focal volume reduction, so useful to many laser applications. Unfortunately, this is not the case, and the physical factors responsible for this unexpected behaviour have been analysed. In particular, we have demonstrated that the three features (M2 factor, divergence and on-axis intensity) do not hold the same information about the spatial characteristics of rectified or unrectified CGBs.

Boubaha, B.; Bencheikh, A.; At-Ameur, K.

2014-02-01

246

Candidate locations for SPS rectifying antennas  

NASA Technical Reports Server (NTRS)

The feasibility of placing 120 Satellite Power System (SPS) rectifying antenna (rectenna) sites across the U.S. was studied. An initial attempt is made to put two land sites in each state using several land site selection criteria. When only 69 land sites are located, it is decided to put the remaining sites in the sea and sea site selection criteria are identified. An estimated projection of electrical demand distribution for the year 2000 is then used to determine the distribution of these sites along the Pacific, Atlantic, and Gulf Coasts. A methodology for distributing rectenna sites across the country and for fine-tuning exact locations is developed, and recommendations on rectenna design and operations are made.

Eberhardt, A. W.

1977-01-01

247

Precision Control of Thermal Transport in Cryogenic Single-Crystal Silicon Devices  

NASA Technical Reports Server (NTRS)

We report on the diffusive-ballistic thermal conductance of multi-moded single-crystal silicon beams measured below 1 K. It is shown that the phonon mean-free-path is a strong function of the surface roughness characteristics of the beams. This effect is enhanced in diffuse beams with lengths much larger than, even when the surface is fairly smooth, 510 nm rms, and the peak thermal wavelength is 0.6 microns. Resonant phonon scattering has been observed in beams with a pitted surface morphology and characteristic pit depth of 30 nm. Hence, if the surface roughness is not adequately controlled, the thermal conductance can vary significantly for diffuse beams fabricated across a wafer. In contrast, when the beam length is of order, the conductance is dominated by ballistic transport and is effectively set by the beam cross-sectional area. We have demonstrated a uniformity of +/-8% in fractional deviation for ballistic beams, and this deviation is largely set by the thermal conductance of diffuse beams that support the micro-electro-mechanical device and electrical leads. In addition, we have found no evidence for excess specific heat in single-crystal silicon membranes. This allows for the precise control of the device heat capacity with normal metal films. We discuss the results in the context of the design and fabrication of large-format arrays of far-infrared and millimeter wavelength cryogenic detectors.

Rostem, K.; Chuss, D. T.; Colazo, F. A.; Crowe, E. J.; Denis, K. L.; Lourie, N. P.; Moseley, S. H.; Stevenson, T. R.; Wollack, E. J.

2014-01-01

248

Precision control of thermal transport in cryogenic single-crystal silicon devices  

NASA Astrophysics Data System (ADS)

We report on the diffusive-ballistic thermal conductance of multi-moded single-crystal silicon beams measured below 1 K. It is shown that the phonon mean-free-path ? is a strong function of the surface roughness characteristics of the beams. This effect is enhanced in diffuse beams with lengths much larger than ?, even when the surface is fairly smooth, 5-10 nm rms, and the peak thermal wavelength is 0.6 ?m. Resonant phonon scattering has been observed in beams with a pitted surface morphology and characteristic pit depth of 30 nm. Hence, if the surface roughness is not adequately controlled, the thermal conductance can vary significantly for diffuse beams fabricated across a wafer. In contrast, when the beam length is of order ?, the conductance is dominated by ballistic transport and is effectively set by the beam cross-sectional area. We have demonstrated a uniformity of 8% in fractional deviation for ballistic beams, and this deviation is largely set by the thermal conductance of diffuse beams that support the micro-electro-mechanical device and electrical leads. In addition, we have found no evidence for excess specific heat in single-crystal silicon membranes. This allows for the precise control of the device heat capacity with normal metal films. We discuss the results in the context of the design and fabrication of large-format arrays of far-infrared and millimeter wavelength cryogenic detectors.

Rostem, K.; Chuss, D. T.; Colazo, F. A.; Crowe, E. J.; Denis, K. L.; Lourie, N. P.; Moseley, S. H.; Stevenson, T. R.; Wollack, E. J.

2014-03-01

249

Simultaneous phosphorus and Si self-diffusion in extrinsic, isotopically controlled silicon heterostructures  

SciTech Connect

We present experimental results of impurity and self-diffusion in an isotopically controlled silicon heterostructure extrinsically doped with phosphorus. As a consequence of extrinsic doping, the concentration of singly negatively charged native defects is enhanced and the role of these native defect charge states in the simultaneous phosphorus and Si self-diffusion can be determined. Multilayers of isotopically controlled {sup 28}Si and natural silicon enable simultaneous analysis of {sup 30}Si self-diffusion into the {sup 28}Si enriched layers and phosphorus diffusion throughout the multilayer structure. An amorphous 260 nm thick Si cap layer was deposited on top of the Si isotope heterostructure. The phosphorus ions were implanted to a depth such that all the radiation damage resided inside this amorphous cap layer, preventing the generation of excess native defects and enabling the determination of the Si self-diffusion coefficient and the phosphorus diffusivity under equilibrium conditions. These samples were annealed at temperatures between 950 and 1100 C to study the diffusion. Detailed analysis of the diffusion process was performed on the basis of a P diffusion model which involves neutral and positively charged mobile P species and neutral and singly negatively charged self-interstitial.

Silvestri, Hughes H.; Bracht, Hartmut A.; Sharp, Ian D.; Hansen, John; Nylandsted-Larsen, Arne; Haller, Eugene E.

2003-04-22

250

Controllable doping and wrap-around contacts to electrolessly etched silicon nanowire arrays  

NASA Astrophysics Data System (ADS)

Top-down electroless chemical etching enables non-lithographic patterning of wafer-scale nanostructured arrays, but the etching on highly doped wafers produces porous structures. The lack of defect-free nanostructures at desired doping and the difficulties in forming reliable electrical side-contacts to the nanostructure arrays limits their integration into high performance nanoelectronics. We developed a barrier layer diffusion technique to controllably dope wafer-scale silicon nanowire arrays (1017-1020 cm-3) produced by chemically etching lightly doped silicon wafers. In order to achieve low resistance top-side electrical contacts to the arrays, we developed a two step tip-doping procedure to locally dope the tips (1020 cm-3) to metallic levels. The dopant concentration is characterized by depth profiling using secondary ion mass spectroscopy and four-point probe electrical measurements. Further, array scale electrical measurements show that the tip-doping lowers the specific contact resistivity (10-5 ? cm2) since the metallic tips enable direct tunneling of electrons across the nickel silicide contacts to the nanowire arrays. This work provides a scalable and cost-effective doping approach to control charge injection and charge conduction in nanowire arrays, thus advancing their integration into various device applications.

Sadhu, Jyothi S.; Tian, Hongxiang; Spila, Timothy; Kim, Junhwan; Azeredo, Bruno; Ferreira, Placid; Sinha, Sanjiv

2014-09-01

251

Photo-assisted control of gold and silver nanostructures on silicon and its SERRS effect  

NASA Astrophysics Data System (ADS)

A facile approach to control the growth of gold nanostructures on n-type silicon by galvanic displacement was demonstrated previously. It was observed that in the presence of light and red laser, at initial stages, gold nano-needles were formed, which then grew perpendicular to the substrate with time. However, the growth process has not yet been understood completely. Here, we have attempted to understand the galvanic displacement phenomena in the presence and absence of light by characterizing the growth process using transmission electron microscopy, atomic force microscopy and x-ray diffraction. Furthermore, we also evaluated the effect of laser on the deposition of silver on silicon wherein the use of green laser resulted in the formation of dendrites, whereas spherical nanoparticles were formed in dark. To further evaluate the benefits of the metal-semiconductor hybrid structure, we also evaluated the surface enhanced resonance Raman spectroscopy (SERRS) of the hybrid substrates and give evidence of the importance of the semiconductor substrate/metal-semiconductor interface in enhancing the SERRS activity.

Lahiri, Abhishek; Wen, Rui; Kuimalee, Surasak; Chowdhury, Anirban; Kobayashi, Shin-ichiro; Zhang, Lisheng; Wang, Peijie; Fang, Yan

2013-07-01

252

Dopant and self-diffusion in extrinsic n-type silicon isotopically controlled heterostructures  

SciTech Connect

We present experimental results of dopant- and self-diffusion in extrinsic silicon doped with As. Multilayers of isotopically controlled {sup 28}Si and natural silicon enable simultaneous analysis of {sup 30}Si diffusion into the {sup 28}Si enriched layers and dopant diffusion throughout the multilayer structure. In order to suppress transient enhanced self- and dopant diffusion caused by ion implantation, we adopted a special approach to dopant introduction. First, an amorphous 250-nm thick Si layer was deposited on top of the Si isotope heterostructure. Then the dopant ions were implanted to a depth such that all the radiation damage resided inside this amorphous cap layer. These samples were annealed for various times and temperatures to study the impact of As diffusion and doping on Si self-diffusion. The Si self-diffusion coefficient and the dopant diffusivity for various extrinsic n-type conditions were determined over a wide temperature range. We observed increased diffusivities that we attribute to the increase in the concentration of the native defect promoting the diffusion.

Silvestri, Hughes H.; Sharp, Ian D.; Bracht, Hartmut A.; Nicols, Sam P.; Beeman, Jeff W.; Hansen, John; Nylandsted-Larsen, Arme; Haller, Eugene E.

2002-04-01

253

High-quality rectifier based on coupled-inductor Sepic topology  

Microsoft Academic Search

A high-quality rectifier employing a coupled-inductor Sepic topology is described, featuring high-frequency insulation and low input current ripple. Moreover, sinusoidal and in-phase input current is obtained even with constant duty-cycle. The magnetic structure is simple and cheap, allowing considerable size and cost reduction. Converter analysis, design criteria of both power and control sections and experimental results are reported in the

G. Spiazzi; L. Rossetto

1994-01-01

254

A high-performance single-phase rectifier with input power factor correction  

Microsoft Academic Search

In this paper, a high-performance single-phase AC-to-DC rectifier with input power factor correction is proposed. The proposed approach has many advantages, including fewer semiconductor components, simplified control, and high-performance features, and satisfies IEC 555 harmonic current standards. Simulation and experimental results obtained on a laboratory prototype are discussed. A hybrid power module of the proposed approach is also shown

Roberto Martinez; Prasad N. Enjeti

1996-01-01

255

Emerging roles for G protein-gated inwardly rectifying potassium (GIRK) channels in health and disease  

Microsoft Academic Search

G protein-gated inwardly rectifying potassium (GIRK) channels hyperpolarize neurons in response to activation of many different G protein-coupled receptors and thus control the excitability of neurons through GIRK-mediated self-inhibition, slow synaptic potentials and volume transmission. GIRK channel function and trafficking are highly dependent on the channel subunit composition. Pharmacological investigations of GIRK channels and studies in animal models suggest that

Christian Lscher; Paul A. Slesinger

2010-01-01

256

Evaluation of ultra-compact rectifiers for low power, high-speed, permanent-magnet generators  

Microsoft Academic Search

Literature reports several future portable and distributed power supplies in the watt to kilowatt range based on rotating machinery equipped with a variable-speed permanent-magnet generator. In order to generate a constant dc voltage, an ultra-compact, highly efficient, low power rectifier is required. In this paper, different topologies are compared concerning losses, volume and control complexity. The most suitable, the half

D. Krahenbuhl; C. Zwyssig; K. Bitterli; M. Imhof; J. W. Kolar

2009-01-01

257

Evaluation of SiC MOSFETs for a High Efficiency Three-Phase Buck Rectifier  

E-print Network

Evaluation of SiC MOSFETs for a High Efficiency Three-Phase Buck Rectifier Fan Xu, Ben Guo, Leon M rectifier for a 400 Vdc architecture data center power supply is designed. The total loss of this rectifier is calculated full load. The results show that the SiC based buck rectifier can obtain low power loss

Tolbert, Leon M.

258

Ann. Sci. Ecole Norm. Sup. UNIFORM RECTIFIABILITY AND HARMONIC MEASURE I  

E-print Network

Ann. Sci. ´Ecole Norm. Sup. UNIFORM RECTIFIABILITY AND HARMONIC MEASURE I: UNIFORM RECTIFIABILITY, with a uniformly rectifiable boundary, which satisfies the Harnack Chain condi- tion plus an interior (but, in which we deduce uniform rectifiability of the boundary, assuming scale invariant Lq bounds, with q > 1

Martell, José María

259

A Full-Wave Rectifier for Interfacing with Multi-Phase Piezoelectric Energy Harvesters*  

E-print Network

A Full-Wave Rectifier for Interfacing with Multi-Phase Piezoelectric Energy Harvesters* N. J: TECHNOLOGY TRENDS: Energy Sources and Energy Harvesting Abstract A full-wave rectifier has been fabricated-electrode piezoelectric transducer to be rectified with reduced output ripple. The rectifier has a measured power

Hurst, Paul J.

260

Physical Layout of High Current Rectifiers: Modern Methods for an Old Challenge  

E-print Network

Physical Layout of High Current Rectifiers: Modern Methods for an Old Challenge JL.Schanen1 , JM rectifier: paralleling components, magnetic field close to the rectifier and also the validation current rectifiers. I. INTRODUCTION Electrochemical process of aluminium involves high DC currents

Paris-Sud XI, Université de

261

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

PubMed

Hybrid density functional theory is used to gain insights into the interaction of intrinsic vacancies (V) and oxygen-vacancy pairs (VO, known as A-centres) with the dopants (D) germanium (Ge), tin (Sn), and lead (Pb) in silicon (Si). We determine the structures as well as binding and formation energies of the DVO and DV complexes. The results are discussed in terms of the density of states and in view of the potential of isovalent doping to control A-centres in Si. We argue that doping with Sn is the most efficient isovalent doping strategy to suppress A-centres by the formation of SnVO complexes, as these are charge neutral and strongly bound. PMID:24667874

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

2014-05-14

262

Controllable surface-plasmon resonance in engineered nanometer epitaxial silicide particles embedded in silicon  

NASA Technical Reports Server (NTRS)

Epitaxial CoSi2 particles in a single-crystal silicon matrix are grown by molecular-beam epitaxy using a technique that allows nanometer control over particle size in three dimensions. These composite layers exhibit resonant absorption predicted by effective-medium theory. Selection of the height and diameter of disklike particles through a choice of growth conditions allows tailoring of the depolarization factor and hence of the surface-plasmon resonance energy. Resonant absorption from 0.49 to 1.04 eV (2.5 to 1.2 micron) is demonstrated and shown to agree well with values predicted by the Garnett (1904, 1906) theory using the bulk dielectric constants for CoSi2 and Si.

Fathauer, R. W.; Ksendzov, A.; Iannelli, J. M.; George, T.

1991-01-01

263

Reflectance control for multicrystalline-silicon photovoltaic modules using textured-dielectric coatings  

SciTech Connect

The authors describe a new approach for controlling the reflectance of photovoltaic modules with planar-surface solar cells. The new approach uses an optically thick, dielectric coating with a large refractive index and a textured surface; this dielectric coating is deposited on the planar-surface solar cell. The textured-dielectric coating works optically with the module encapsulation to promote optical confinement of rays inside the module encapsulation structure, which reduces the net reflectance of the photovoltaic module. The advantage of this approach is that deposition of a textured-dielectric film may be less costly and less intrusive on the cell manufacturing process than texturing multicrystalline-silicon substrates. The authors present detailed optical models and experimental confirmation of the new approach.

Gee, J.M.; Tardy, H.L.; Hund, T.D. [Sandia National Labs., Albuquerque, NM (United States); Gordon, R.; Liang, H. [Harvard Univ., Cambridge, MA (United States). Dept. of Chemistry

1995-01-01

264

Amorphous Silicon-Carbon Alloy Prepared by the CMP (Controlled Plasma Magnetron) Method  

NASA Astrophysics Data System (ADS)

Hydrogenated amorphous silicon-carbon (a-SiC) films were fabricated using a novel plasma CVD method, called the CPM (Controlled Plasma Magnetron) method. The films obtained had a large Si-C bond density and a low Si-H bond density. The absorption coefficient at the photon energy level of 2.5 to 3.5 eV for these films was one order of magnitude lower than that for conventional a-SiC films. Furthermore, the dark conductivity of boron-doped films increased to more than 10-4 (?\\cdotcm)-1, which is the highest value achieved for a-SiC with a carbon content of 55%.

Nishikuni, Masato; Ninomiya, Kunimoto; Okamoto, Singo; Takahama, Tsuyoshi; Tsuda, Shinya; Ohnishi, Michitoshi; Nakano, Shoichi; Kuwano, Yukinori

1991-01-01

265

Improved performance alternator with fully integrated Switched-Mode Rectifier  

E-print Network

The use of Power Electronic circuits has helped to advance the technology of automotive alternators. The use of a Switched-Mode Rectifier (SMR) allows the alternator to run at a load-matched condition, optimizing power and ...

Mesa, Armando

2008-01-01

266

Performance Improvement of Alternators With Switched-Mode Rectifiers  

E-print Network

The use of a switched-mode rectifier (SMR) allows automotive alternators to operate at a load-matched condition at all operating speeds, overcoming the limitation of optimum performance at just one speed. While use of an ...

Rivas, Juan M.

267

Duke Math. J. UNIFORM RECTIFIABILITY AND HARMONIC MEASURE II  

E-print Network

RECTIFIABILITY STEVE HOFMANN, JOS´E MAR´IA MARTELL, AND IGNACIO URIARTE-TUERO Abstract. We present the converse HOFMANN, JOS´E MAR´IA MARTELL, AND IGNACIO URIARTE-TUERO 1. Introduction This paper is a sequel

Martell, José María

268

Room temperature coherent control of defect spin qubits in silicon carbide.  

PubMed

Electronic spins in semiconductors have been used extensively to explore the limits of external control over quantum mechanical phenomena. A long-standing goal of this research has been to identify or develop robust quantum systems that can be easily manipulated, for future use in advanced information and communication technologies. Recently, a point defect in diamond known as the nitrogen-vacancy centre has attracted a great deal of interest because it possesses an atomic-scale electronic spin state that can be used as an individually addressable, solid-state quantum bit (qubit), even at room temperature. These exceptional quantum properties have motivated efforts to identify similar defects in other semiconductors, as they may offer an expanded range of functionality not available to the diamond nitrogen-vacancy centre. Notably, several defects in silicon carbide (SiC) have been suggested as good candidates for exploration, owing to a combination of computational predictions and magnetic resonance data. Here we demonstrate that several defect spin states in the 4H polytype of SiC (4H-SiC) can be optically addressed and coherently controlled in the time domain at temperatures ranging from 20 to 300 kelvin. Using optical and microwave techniques similar to those used with diamond nitrogen-vacancy qubits, we study the spin-1 ground state of each of four inequivalent forms of the neutral carbon-silicon divacancy, as well as a pair of defect spin states of unidentified origin. These defects are optically active near telecommunication wavelengths, and are found in a host material for which there already exist industrial-scale crystal growth and advanced microfabrication techniques. In addition, they possess desirable spin coherence properties that are comparable to those of the diamond nitrogen-vacancy centre. This makes them promising candidates for various photonic, spintronic and quantum information applications that merge quantum degrees of freedom with classical electronic and optical technologies. PMID:22051676

Koehl, William F; Buckley, Bob B; Heremans, F Joseph; Calusine, Greg; Awschalom, David D

2011-11-01

269

A method of rectifying current at microscales  

NASA Astrophysics Data System (ADS)

A method for rectifying electric current in micro and nanoscale devices is proposed based on the asymmetric concentration of polarization in an electrolyte solution in the case where the current in a microdiode successively passes through two mutually undissolvable fluids with different dielectric constants and diffusion coefficients in tubes with different dimensions. It is assumed that both fluids contain the ions of a completely dissociated substance which provide electric charge transfer upon application of a potential difference to the walls of the device, and the interface between the two fluids has a charge. The process is described by a one-dimensional nonstationary Nernst-Planck-Poisson system. The boundary conditions on the electrodes are the impermeability condition for anions and the Arrhenius equation which defines the flow of cations. The system of equations was solved numerically: the unknowns were decomposed into a complete system of orthogonal functions of the spatial variable, and the resulting dynamical system for the Galerkin coefficients was integrated over time by the Gear method because of its stiffness. The parameters of the system that have the most significant effect on the degree of rectification are determined, and their optimum values are evaluated.

Demekhin, E. A.; Baryshev, M. G.; Ganchenko, G. S.; Gorbacheva, E. V.

2014-09-01

270

Uniform rectifiability and harmonic measure II: Poisson kernels in $L^p$ imply uniform rectifiability  

E-print Network

We present the converse to a higher dimensional, scale-invariant version of a classical theorem of F. and M. Riesz. More precisely, for $n\\geq 2$, for an ADR domain $\\Omega\\subset \\re^{n+1}$ which satisfies the Harnack Chain condition plus an interior (but not exterior) Corkscrew condition, we show that absolute continuity of harmonic measure with respect to surface measure on $\\partial\\Omega$, with scale invariant higher integrability of the Poisson kernel, is sufficient to imply uniformly rectifiable of $\\partial\\Omega$.

Hofmann, Steve; Uriarte-Tuero, Ignacio

2012-01-01

271

Silane coupling agent bearing a photoremovable succinimidyl carbonate for patterning amines on glass and silicon surfaces with controlled surface densities  

Microsoft Academic Search

Patterned immobilization of synthetic and biological ligands on material surfaces with controlled surface densities is important for various bioanalytical and cell biological purposes. This paper describes the synthesis, characterization, and application of a novel silane coupling agent bearing a photoremovable succinimidyl carbonate, which enables the photopatterning of various primary amines on glass and silicon surfaces. The silane coupling agent is

Hidekazu Nakayama; Jun Nakanishi; Takahiro Shimizu; Yutaro Yoshino; Hideo Iwai; Shingo Kaneko; Yasuhiro Horiike; Kazuo Yamaguchi

2010-01-01

272

Rectifying effect through the interface of SrTiO3??/GaAs heterojunctions  

NASA Astrophysics Data System (ADS)

Oxides-semiconductor junctions have attracted great attention and exhibited promising potential in integrated devices in which the passing current is controlled by applying voltage. It is found that an oxygen-deficient SrTiO3−δ/p-GaAs junction displays an obvious rectifying effect. The SrTiO3−δ thin film is in the anomalous in-plain compressive strain, as confirmed by structural characterization. Investigations on the current–voltage curve show that the current decreases with the increasing temperature at the reverse bias, which suggests that the rectifying behavior may be attributed to the strain-assisted tunneling mechanism. The effect of strain or film thickness on the transport property is also discussed.

Zhai, Z. Y.; Xie, Q. Y.; Chen, G. B.; Yu, A. L.; Zhang, F. M.; Wu, X. S.

2014-11-01

273

Phosphoinositide regulation of inward rectifier potassium (Kir) channels  

PubMed Central

Inward rectifier potassium (Kir) channels are integral membrane proteins charged with a key role in establishing the resting membrane potential of excitable cells through selective control of the permeation of K+ ions across cell membranes. In conjunction with secondary anionic phospholipids, members of this family are directly regulated by phosphoinositides (PIPs) in the absence of other proteins or downstream signaling pathways. Different Kir isoforms display distinct specificities for the activating PIPs but all eukaryotic Kir channels are activated by PI(4,5)P2. On the other hand, the bacterial KirBac1.1 channel is inhibited by PIPs. Recent crystal structures of eukaryotic Kir channels in apo and lipid bound forms reveal one specific binding site per subunit, formed at the interface of N- and C-terminal domains, just beyond the transmembrane segments and clearly involving some of the key residues previously identified as controlling PI(4,5)P2 sensitivity. Computational, biochemical, and biophysical approaches have attempted to address the energetic determinants of PIP binding and selectivity among Kir channel isoforms, as well as the conformational changes that trigger channel gating. Here we review our current understanding of the molecular determinants of PIP regulation of Kir channel activity, including in context with other lipid modulators, and provide further discussion on the key questions that remain to be answered. PMID:24409153

Furst, Oliver; Mondou, Benoit; D'Avanzo, Nazzareno

2014-01-01

274

Offshore wind farm grid connection using a novel diode-rectifier and VSC-inverter based HVDC transmission link  

Microsoft Academic Search

This paper carries out a technical feasibility study on the use of HVDC diode based rectifiers for the connection of large off-shore wind farms, together with an on-shore voltage source converter. An integrated control technique for the overall system is developed and validated by means of PSCAD simulation of the distributed wind farm together with the complete HVDC link. The

S. Bernal-Perez; S. Ano-Villalba; R. Blasco-Gimenez; J. Rodriguez-D'Derlee

2011-01-01

275

Gas-phase processing of the silicon surface toward controlled coverage with selected species  

NASA Astrophysics Data System (ADS)

As the level of contamination introduced to the surface is reduced through the use of cleaner chemicals and processes, the emphasis of cleaning is shifting from one of removing incidental contaminants to that of controlling the condition of the surface inherently produced by the preceding process and bridging the condition of the surface left by the preceding process steps with the requirements for the surface condition prior to the next process. Gas-phase processes, which can be integrated into vacuum based equipment, have generated interest because of the greater degree of process control which can be used to condition the surface. In this study, the differences between silicon surfaces produced through the AHF:methanol and dilute HF oxide etch processes were explored through X-ray Photoelectron Spectroscopy (XPS), metal-silicon contact characteristics, and MOS characterization. The presence of fluorine on the surface following the AHF:methanol process was the most significant difference between these surfaces. Reduced stress at the Si/SiOsb2 interface, retardation of thermal oxidation, and improved gate oxide integrity were observed on the AHF:methanol surface. A contactless surface photovoltage technique was used to monitor the surface evolution following gas-cleaning sequences, and the differences in surface activity were related to the chemical composition of the surface through XPS. The UV/Clsb2 process, which is used to remove metallic contamination from the surface in the gas phase, also removed most of the fluorine from the surface after the AHF:methanol. The post-UV/Clsb2 surface yielded oxides with improved gate oxide integrity, indicating that the level of fluorine remaining on the surface following the AHF:methanol etch process is not optimal for growth of thin oxides. Stable oxygen passivated surfaces were obtained through a methanol adsorption + UV/Osb2 process, which removed chlorine from the surface without introducing Si-OH. MOS characterization showed an improvement in the charge-to breakdown statistics of oxides grown on these surfaces. Overall, the results obtained indicate that gas-phase cleaning processes offer a potentially greater degree of control of the condition of the surface over aqueous processes and may find useful application in areas where requirements for surface conditioning are not met by liquid-phase chemistries.

Staffa, James Andrew

276

Deconvolving the controls on the deep ocean's silicon stable isotope distribution  

NASA Astrophysics Data System (ADS)

We trace the marine biogeochemical silicon (Si) cycle using the stable isotope composition of Si dissolved in seawater (expressed as ?30Si). Open ocean ?30Si observations indicate a surprisingly strong influence of the physical circulation on the large-scale marine Si distribution. Here, we present an ocean general circulation model simulation that deconvolves the physical and biogeochemical controls on the ?30Si distribution in the deep oceanic interior. By parsing dissolved Si into its preformed and regenerated components, we separate the influence of deep water formation and circulation from the effects of biogeochemical cycling related to opal dissolution at depth. We show that the systematic meridional ?30Si gradient observed in the deep Atlantic Ocean is primarily determined by the preformed component of Si, whose distribution in the interior is controlled solely by the circulation. We also demonstrate that the ?30Si value of the regenerated component of Si in the global deep ocean is dominantly set by oceanic regions where opal export fluxes to the deep ocean are large, i.e. primarily in the Southern Ocean's opal belt. The global importance of this regionally dynamic Si cycling helps explain the observed strong physical control on the oceanic ?30Si distribution, since most of the regenerated Si present within the deep Atlantic and Indo-Pacific Oceans is in fact transported into these basins by deep waters flowing northward from the Southern Ocean. Our results thus provide a mechanistic explanation for the observed ?30Si distribution that emphasizes the dominant importance of the Southern Ocean in the marine Si cycle.

de Souza, Gregory F.; Slater, Richard D.; Dunne, John P.; Sarmiento, Jorge L.

2014-07-01

277

Controllable chemical vapor deposition of large area uniform nanocrystalline graphene directly on silicon dioxide  

NASA Astrophysics Data System (ADS)

Metal-catalyst-free chemical vapor deposition (CVD) of large area uniform nanocrystalline graphene on oxidized silicon substrates is demonstrated. The material grows slowly, allowing for thickness control down to monolayer graphene. The as-grown thin films are continuous with no observable pinholes, and are smooth and uniform across whole wafers, as inspected by optical-, scanning electron-, and atomic force microscopy. The sp2 hybridized carbon structure is confirmed by Raman spectroscopy. Room temperature electrical measurements show ohmic behavior (sheet resistance similar to exfoliated graphene) and up to 13% of electric-field effect. The Hall mobility is 40 cm2/Vs, which is an order of magnitude higher than previously reported values for nanocrystalline graphene. Transmission electron microscopy, Raman spectroscopy, and transport measurements indicate a graphene crystalline domain size 10 nm. The absence of transfer to another substrate allows avoidance of wrinkles, holes, and etching residues which are usually detrimental to device performance. This work provides a broader perspective of graphene CVD and shows a viable route toward applications involving transparent electrodes.

Sun, Jie; Lindvall, Niclas; Cole, Matthew T.; Wang, Teng; Booth, Tim J.; Bggild, Peter; Teo, Kenneth B. K.; Liu, Johan; Yurgens, August

2012-02-01

278

Stress control of plasma enhanced chemical vapor deposited silicon oxide film from tetraethoxysilane  

NASA Astrophysics Data System (ADS)

Thin silicon dioxide films have been studied as a function of deposition parameters and annealing temperatures. Films were deposited by tetraethoxysilane (TEOS) dual-frequency plasma enhanced chemical vapor deposition with different time interval fractions of high-frequency and low-frequency plasma depositions. The samples were subsequently annealed up to 930 C to investigate their stress behavior. Films that were deposited in high-frequency dominated plasma were found to have tensile residual stress after annealing at temperatures higher than 800 C. The residual stress can be controlled to slightly tensile by changing the annealing temperature. High tensile stress was observed during the annealing of high-frequency plasma-deposited films, leading to film cracks that limit the film thickness, as predicted by the strain energy release rate equation. Thick films without cracks were obtained by iterating deposition and annealing to stack multiple layers. A series of wet cleaning experiments were conducted, and we discovered that water absorption in high-frequency plasma-deposited films causes the residual stress to decrease. A ?40 nm thick low-frequency deposited oxide cap is sufficient to prevent water from diffusing through the film. Large-area free-standing tensile stressed oxide membranes without risk of buckling were successfully fabricated.

Guan, D.; Bruccoleri, A. R.; Heilmann, R. K.; Schattenburg, M. L.

2014-02-01

279

Controllable light-induced conic structures in silicon nanowire arrays by metal-assisted chemical etching.  

PubMed

Silicon nanowires (SiNWs) have long been considered a promising material due to their extraordinary electrical and optical properties. As a simple, highly efficient fabrication method for SiNWs, metal-assisted chemical etching (MACE) has been intensively studied over recent years. However, effective control by modulation of simple parameters is still a challenging topic and some key questions still remain in the mechanistic processes. In this work, a novel method to manipulate SiNWs with a light-modulated MACE process has been systematically investigated. Conic structures consisting of inclined and clustered SiNWs can be generated and effectively modified by the incident light while new patterns such as 'bamboo shoot' arrays can also be formed under certain conditions. More importantly, detailed study has revealed a new top-down 'diverting etching' model of the conic structures in this process, different from the previously proposed 'bending' model. As a consequence of this mechanism, preferential lateral mass transport of silver particles occurs. Evidence suggests a relationship of this phenomenon to the inhomogeneous distribution of the light-induced electron-hole pairs beneath the etching front. Study on the morphological change and related mechanism will hopefully open new routes to understand and modulate the formation of SiNWs and other nanostructures. PMID:24334462

Zhang, Shenli; Wang, Xinwei; Liu, Hong; Shen, Wenzhong

2014-01-17

280

Refractive Index Control of SiO2 Films by Pulsed Laser Deposition with Silicone Targets  

NASA Astrophysics Data System (ADS)

We fabricated layered structures of SiO2 films with different refractive indices by pulsed laser deposition with silicone targets. The refractive index of SiO2 films could be controlled by the deposition rate. Lowering of the deposition rate helped to make a dense film, showing higher refractive index. A 0.4-?m-thick SiO2 cladding film deposited at 0.1 nm/pulse was first formed on the entire surface of a Si wafer, and then a 1-?m-thick SiO2 core film was deposited at 0.05 nm/pulse in a line of 1 mm width on the sample. The deposited films were free of impurities such as H2O and carbon. Transparent, tightly layered structures were obtained. The layered structures could also be fabricated on a flexible substrate consisting of a 100-?m-thick polyester sheet. Both samples functioned as an optical waveguide for a 633-nm He-Ne laser. The single-mode propagations were observed as designed.

Okoshi, Masayuki; Kuramatsu, Masaaki; Inoue, Narumi

2002-09-01

281

Precision control of thermal transport in cryogenic single-crystal silicon devices  

E-print Network

We report on the diffusive-ballistic thermal conductance of multi-moded single-crystal silicon beams measured below 1 K. It is shown that the phonon mean-free-path $\\ell$ is a strong function of the surface roughness characteristics of the beams. This effect is enhanced in diffuse beams with lengths much larger than $\\ell$, even when the surface is fairly smooth, 5-10 nm rms, and the peak thermal wavelength is 0.6 $\\mu$m. Resonant phonon scattering has been observed in beams with a pitted surface morphology and characteristic pit depth of 30 nm. Hence, if the surface roughness is not adequately controlled, the thermal conductance can vary significantly for diffuse beams fabricated across a wafer. In contrast, when the beam length is of order $\\ell$, the conductance is dominated by ballistic transport and is effectively set by the beam area. We have demonstrated a uniformity of $\\pm$8% in fractional deviation for ballistic beams, and this deviation is largely set by the thermal conductance of diffuse beams tha...

Rostem, Karwan; Colazo, Felipe A; Crowe, Erik J; Denis, Kevin L; Lourie, Nathan P; Moseley, Samuel H; Stevenson, Thomas R; Wollack, Edward J

2014-01-01

282

Silicon-in-silica spheres via axial thermal gradient in-fibre capillary instabilities.  

PubMed

The ability to produce small scale, crystalline silicon spheres is of significant technological and scientific importance, yet scalable methods for doing so have remained elusive. Here we demonstrate a silicon nanosphere fabrication process based on an optical fibre drawing technique. A silica-cladded silicon-core fibre with diameters down to 340?nm is continuously fed into a flame defining an axial thermal gradient and the continuous formation of spheres whose size is controlled by the feed speed is demonstrated. In particular, spheres of diameter <500?nm smaller than those produced under isothermal heating conditions are shown and analysed. A fibre with dual cores, p-type and n-type silicon, is drawn and processed into spheres. Spatially coherent break-up leads to the joining of the spheres into a bispherical silicon 'p-n molecule'. The resulting device is measured to reveal a rectifying I-V curve consistent with the formation of a p-n junction. PMID:23900398

Gumennik, Alexander; Wei, Lei; Lestoquoy, Guillaume; Stolyarov, Alexander M; Jia, Xiaoting; Rekemeyer, Paul H; Smith, Matthew J; Liang, Xiangdong; Grena, Benjamin J-B; Johnson, Steven G; Grade?ak, Silvija; Abouraddy, Ayman F; Joannopoulos, John D; Fink, Yoel

2013-01-01

283

Non-equilibrium 1/f noise in rectifying nanopores  

SciTech Connect

We report a single rectifying conically shaped nanopore system with ion current fluctuations whose 1/f noise characteristics observed at low frequencies are voltage dependent. Switching the voltage polarity allows one to switch between a system that produces equilibrium and nonequilibrium 1/f ion current fluctuations. The nonequilibrium fluctuations in the high-conductance state of the device are characterized by exponential dependence of the normalized power spectrum on voltage. The asymmetric 1/f noise is found characteristic for rectifying polymer nanopores and absent in pores with Ohmic current-voltage curves.

Vlassiouk, Ivan V [ORNL

2009-01-01

284

Control of silicon solidification and the impurities from an Al-Si melt  

NASA Astrophysics Data System (ADS)

The investigation on purification of metallurgical grade silicon by solidification of hypereutectic Al-Si melt under the temperature gradient as an intensified separation way was carried out. Based on the available thermodynamic parameters and experimental data, the thermodynamic behavior and chemical composition of metallic impurities was studied in the solidification process. The principle for the silicon growth in the Al-Si melts was investigated. The results indicated that the refined silicon grains were successfully enriched at the top of the Al-Si alloy. Then the top part refined silicon was collected by aqua regia leaching. Electrorefining of the bottom part (Al-22%Si) was investigated effectively in view of recovering pure Si and Al. Additionally, according to previous investigation, the optimized technical process for SOG-Si production was proposed.

Wang, Panpan; Lu, Huimin; Lai, Yuanshi

2014-03-01

285

Silicon carbide process development for microengine applications : residual stress control and microfabrication  

E-print Network

The high power densities expected for the MIT microengine (silicon MEMS-based micro-gas turbine generator) require the turbine and compressor spool to rotate at a very high speed at elevated temperatures (1300 to 1700 K). ...

Choi, Dongwon, 1973-

2004-01-01

286

Optimization of silicon-germanium TFT's through the control of amorphous precursor characteristics  

Microsoft Academic Search

Polycrystalline thin-film transistors (TFT's) are promising for use as high-performance pixel and integrated driver transistors for active matrix liquid crystal displays (AMLCD's). Silicon-germanium is a promising candidate for use as the channel material due to its low thermal budget requirements. The binary nature of the silicon-germanium system complicates the optimization of the channel deposition conditions. To date, little work has

Vivek Subramanian; Krishna C. Saraswat

1998-01-01

287

Damping of a parallel AC-DC power system using PID power system stabilizers and rectifier current regulators  

Microsoft Academic Search

A scheme for improving the dynamic stability of a parallel AC-DC power system is presented. It uses a proportional-integral-derivative (PID) power-system stabilizer and a PID rectifier current regulator to enhance the damping for the electromechanical mode of the system. The parameters of the proposed PID controllers are determined using a unified approach based on modal control theory. Eigenvalue analyses are

Yuan-Yih Hsu; L. Wang

1988-01-01

288

Design and Evaluation of a 42-V Automotive Alternator With Integrated Switched-Mode Rectifier  

E-print Network

This paper presents techniques for the design of high-power Lundell alternators with integrated switched-mode rectifiers. A multisection stator winding and interleaved rectifier arrangement is introduced that enables high ...

Tang, Sai Chun

289

Identification of Native Atrial G-protein-regulated Inwardly Rectifying K (GIRK4) Channel Homomultimers*  

E-print Network

Identification of Native Atrial G-protein-regulated Inwardly Rectifying K (GIRK4) Channel-protein-regulated inwardly rectifying K (GIRK) channels play critical inhibitory roles throughout the nervous system, heart

Clapham, David E.

290

Analysis and Implementation of an Improved Current-Doubler Rectifier With Coupled Inductors  

Microsoft Academic Search

In this paper, an improved current-doubler rectifier with coupled inductors is proposed. The proposed rectifier can extend duty ratio to reduce the peak current through the isolation transformer winding and lower output current ripple as well as voltage stress of the rectifier diodes. In this study, a 500-W prototype with a full-bridge phase-shift converter, the proposed rectifier, with input voltage

Tsai-Fu Wu; Cheng-Tao Tsai; Yaow-Ming Chen; Y.-D. Chang

2008-01-01

291

Method of seismic data enhancement using a phase of rectified trace seismic parameter  

SciTech Connect

The method is described of developing a specific seismic data parameter from seismic trace data, comprising: receiving processed seismic trace data for a selected plane of investigation; rectifying the seismic trace data; producing the Hilbert transform of the rectified trace data; determining the instantaneous phase using Hilbert transformed rectified data; and interpreting geological significance of the plane of investigation using instantaneous phase of the rectified and transformed data.

Stebens, B.; Parsons, R.K.; Baumel, R.T.; Terral, D.K.; Yedlin, M.J.

1986-12-30

292

Doping controlled roughness and defined mesoporosity in chemically etched silicon nanowires with tunable conductivity  

NASA Astrophysics Data System (ADS)

By using Si(100) with different dopant type (n++-type (As) or p-type (B)), we show how metal-assisted chemically etched (MACE) nanowires (NWs) can form with rough outer surfaces around a solid NW core for p-type NWs, and a unique, defined mesoporous structure for highly doped n-type NWs. We used high resolution electron microscopy techniques to define the characteristic roughening and mesoporous structure within the NWs and how such structures can form due to a judicious choice of carrier concentration and dopant type. The n-type NWs have a mesoporosity that is defined by equidistant pores in all directions, and the inter-pore distance is correlated to the effective depletion region width at the reduction potential of the catalyst at the silicon surface in a HF electrolyte. Clumping in n-type MACE Si NWs is also shown to be characteristic of mesoporous NWs when etched as high density NW layers, due to low rigidity (high porosity). Electrical transport investigations show that the etched nanowires exhibit tunable conductance changes, where the largest resistance increase is found for highly mesoporous n-type Si NWs, in spite of their very high electronic carrier concentration. This understanding can be adapted to any low-dimensional semiconducting system capable of selective etching through electroless, and possibly electrochemical, means. The process points to a method of multiscale nanostructuring NWs, from surface roughening of NWs with controllable lengths to defined mesoporosity formation, and may be applicable to applications where high surface area, electrical connectivity, tunable surface structure, and internal porosity are required.

McSweeney, W.; Lotty, O.; Mogili, N. V. V.; Glynn, C.; Geaney, H.; Tanner, D.; Holmes, J. D.; O'Dwyer, C.

2013-07-01

293

Power MOSFET Basics Vrej Barkhordarian, International Rectifier, El Segundo, Ca.  

E-print Network

Power MOSFET Basics Vrej Barkhordarian, International Rectifier, El Segundo, Ca. Discrete power in VLSI devices. The metal oxide semiconductor field effect transistor (MOSFET) is based on the original complicated and hence more expensive than the power MOSFET. Source Contact Field Oxide Gate Oxide Gate

Paderborn, Universität

294

35 GHz integrated circuit rectifying antenna with 33 percent efficiency  

NASA Technical Reports Server (NTRS)

A 35 GHz integrated circuit rectifying antenna (rectenna) has been developed using a microstrip dipole antenna and beam-lead mixer diode. Greater than 33 percent conversion efficiency has been achieved. The circuit should have applications in microwave/millimeter-wave power transmission and detection.

Yoo, T.-W.; Chang, K.

1991-01-01

295

Rectifier-Inverter Frequency Changers with Suppressed DC Link Components  

Microsoft Academic Search

Rectifier-inverter types of static frequency changers (SFC's) typically employ bulky dc link reactive components to establish the required dc bus voltage. The negative effects of these components on overall system performance and evolution have been the subject of many past research publications. It is demonstrated that these unwanted components can be eliminated through the use of suitable SFC power circuit

Phoivos D. Ziogas; Young-Goo Kang; Victor R. Stefanovic

1986-01-01

296

Stability Analysis of a Rectifier-Inverter Induction Motor Drive  

Microsoft Academic Search

A stability study of a rectifier-inverter induction motor drive system is performed by neglecting the harmonic content of the stator voltages and applying Nyquist stability criterion to the small- displacement equations obtained by linearization about an operating point. This investigation reveals that system instability can occur over a wide speed range if the system parameters are improperly selected. It appears

Thomas Lipo; Paul Krause

1969-01-01

297

Flywheel-generator-rectifiers as large magnet pulsed power supplies  

Microsoft Academic Search

A typical generator-rectifier, which would be suitable for a magnet pulsed power supply is described and the fundamental machine equations used to create an original mathematical model. The model is used to examine the operation of the supply under typical load conditions and the discussion of the results is related to the generator design.

J. B. Hicks

1976-01-01

298

Optics to rectify CORONA panoramic photographs for map making  

NASA Astrophysics Data System (ADS)

In the 1960's, accurate maps of the United States were available to all, from the U.S. Government, but maps of the Soviet Union were not, and in fact were classified. Maps of the Soviet Union were needed by the U.S. Government, including for U.S. targeting of Soviet ICBM sites, and for negotiating the SALT ICBM disarmament treaty. Although mapping cameras were historically frame cameras with low distortion, the CORONA panoramic film coverage was used to identify any ICBM sites. If distortion-free photographs could be produced from this inherently distorted panoramic material, accurate maps could be produced that would be valuable. Use of the stereo photographs from CORONA, for developing accurate topographical maps, was the mission of Itek's Gamma Rectifier. Bob Shannon's department at Itek was responsible for designing the optics for the Gamma Rectifier. He assigned the design to the author. The optical requirements of this system are described along with the optical design solution, which allowed the inherent panoramic distortion of the original photographs to be "rectified" to a very high level of accuracy, in enlarged photographs. These rectifiers were used three shifts a day, for over a decade, and produced the most accurate maps of the earth's surface, that existed at that time. The results facilitated the success of the Strategic Arms Limitation Talks (SALT) Treaty signed by the US and the Soviet Union in 1972, which were verified by "national means of verification" (i.e. space reconnaissance).

Hilbert, Robert S.

2006-08-01

299

The effect of silica nucleation layers on grain control of multi-crystalline silicon in directional solidification  

NASA Astrophysics Data System (ADS)

The grain control in multi-crystalline silicon growth by directional solidification is crucial to the ingot quality. In order to study the nucleation and grain growth behavior, we carried out ingot growth using porous silica coatings, with different Si/SiO2 ratios, and the traditional nitride coating for comparison, at the bottom of a small crucible. It was observed that with more silica in the coating, smaller and uniform grains, as well as columnar growth, could be obtained. As a result, more non-? grain boundaries were found as well. On the contrary, as silicon became a continuous phase in the coating, the grain refinement was less effective and their grain development in the porous coating was examined. The possible grain nucleation and growth mechanisms in the porous coatings were further proposed.

Wong, Y. T.; Hsieh, C. T.; Lan, A.; Hsu, C.; Lan, C. W.

2014-10-01

300

Enhanced photocurrent in thin-film amorphous silicon solar cells via shape controlled three-dimensional nanostructures  

NASA Astrophysics Data System (ADS)

In this paper, we have explored manufacturable approaches to sub-wavelength controlled three-dimensional (3D) nano-patterns with the goal of significantly enhancing the photocurrent in amorphous silicon solar cells. Here we demonstrate efficiency enhancement of about 50% over typical flat a-Si thin-film solar cells, and report an enhancement of 20% in optical absorption over Asahi textured glass by fabricating sub-wavelength nano-patterned a-Si on glass substrates. External quantum efficiency showed superior results for the 3D nano-patterned thin-film solar cells due to enhancement of broadband optical absorption. The results further indicate that this enhanced light trapping is achieved with minimal parasitic absorption losses in the deposited transparent conductive oxide for the nano-patterned substrate thin-film amorphous silicon solar cell configuration. Optical simulations are in good agreement with experimental results, and also show a significant enhancement in optical absorption, quantum efficiency and photocurrent.

Hilali, Mohamed M.; Yang, Shuqiang; Miller, Mike; Xu, Frank; Banerjee, Sanjay; Sreenivasan, S. V.

2012-10-01

301

Subunit Stoichiometry of a Heteromultimeric G protein-coupled Inward-rectifier K Channel*  

E-print Network

Subunit Stoichiometry of a Heteromultimeric G protein-coupled Inward-rectifier K Channel* (Received subunits (4­7). More recently, two members of the inward-rectifier class, IRK1 (8) and ROMK1 (9), have also-protein-coupled inward rectifiers (GIRKs).1 In par- ticular, coexpression of GIRK1 and GIRK4 (CIR) produces

Silverman, Scott K.

302

High-Efficiency X-Band MMIC GaN Power Amplifiers Operating as Rectifiers  

E-print Network

High-Efficiency X-Band MMIC GaN Power Amplifiers Operating as Rectifiers Michael Litchfield, Scott presents a performance evaluation of GaN X-Band power amplifiers operating as self-synchronous rectifiers = 20 V in deep class-AB bias, respec tively. In rectifier mode, biased in class-C, the same MMICs show

Popovic, Zoya

303

RECTIFIABLE CURVES IN SIERPI NSKI CARPETS ESTIBALITZ DURAND-CARTAGENA AND JEREMY T. TYSON  

E-print Network

RECTIFIABLE CURVES IN SIERPI ´NSKI CARPETS ESTIBALITZ DURAND-CARTAGENA AND JEREMY T. TYSON Abstract toral billiards. Our results provide a first step towards a description of the rectifiable curves of quasiconformal and bi-Lipschitz maps between carpets. Characterize the rectifiable curves contained in a given

304

Inhibitory Interactions between Two Inward Rectifier K Channel Subunits Mediated by the Transmembrane Domains*  

E-print Network

Inhibitory Interactions between Two Inward Rectifier K Channel Subunits Mediated Inwardly rectifying K channel subunits may form homomeric or heteromeric channels with distinct func.1 chan- nels evoke inwardly rectifying K currents which acti- vate rapidly and undergo a pronounced decay

Tucker, Stephen J.

305

A SET CONTAINING RECTIFIABLE ARCS QC-LOCALLY BUT NOT QC-GLOBALLY  

E-print Network

A SET CONTAINING RECTIFIABLE ARCS QC-LOCALLY BUT NOT QC-GLOBALLY CHRISTOPHER J. BISHOP Abstract. We image of E contains rectifiable curves, but such that E has some quasiconformal image containing no non-constant rectifiable curves. 1991 Mathematics Subject Classification. Primary: 30C62 Secondary: Key words and phrases

Bishop, Christopher

306

Current Spectra Translation in Single Phase Rectifiers: Implications to Active Power Factor Corrections  

E-print Network

fEs(? 9t Current Spectra Translation in Single Phase Rectifiers: Implications to Active Power spectra translation of a line commutated single phase full wave rectifier. Analytical expressions systems. The proposed theory is supported by computer simulation. harmonic contentof the rectified side

307

ICNC'05 -FSKD'05, Aug.27th, 2005 Pattern Classification using Rectified  

E-print Network

ICNC'05 - FSKD'05, Aug.27th, 2005 Pattern Classification using Rectified Nearest Feature Line) · T.M. Cover and P.E. Hart,1967 Nearest Feature Line (NFL) · S.Z. Li and J. Lu, 1999 Rectified area, causing decision errors #12;Rectified NFL-Segment Idea : remove all the feature lines trespassing

Washington at Seattle, University of

308

CALDERON-ZYGMUND KERNELS AND RECTIFIABILITY IN V. CHOUSIONIS, J. MATEU, L. PRAT, AND X. TOLSA  

E-print Network

CALDER´ON-ZYGMUND KERNELS AND RECTIFIABILITY IN THE PLANE V. CHOUSIONIS, J. MATEU, L. PRAT, AND X even to one of its coordinate parts x/|z|2 , y/|z|2 , z = (x, y) C) implies that E is rectifiable. We -boundedness implies rectifiability. 1. Introduction Let µ be a positive, continuous, that is without atoms

Tolsa, Xavier

309

A new class of (H k , 1)rectifiable subsets of metric R. Ghezzi + , F. Jean #  

E-print Network

A new class of (H k , 1)­rectifiable subsets of metric spaces # R. Ghezzi + , F. Jean # September--Carath??eodory spaces, where the class of 1­rectifiable sets does not contain smooth non­horizontal curves; therefore a new definition of rectifiable sets including non­horizontal curves is needed. This is why we introduce

310

Compactness of Rectifiable Currents in a Metric Space Suppose u BV (Rk  

E-print Network

Compactness of Rectifiable Currents in a Metric Space Suppose u BV (Rk ) we define(x)} rectifiable currents in E equipped), then, for some Lk null set N in Rk , the set yRk\\N spt S(y) is k rectifiable. Proof : By the finiteness

Hardt, Robert

311

IMPROVING DEEP NEURAL NETWORKS FOR LVCSR USING RECTIFIED LINEAR UNITS AND DROPOUT  

E-print Network

IMPROVING DEEP NEURAL NETWORKS FOR LVCSR USING RECTIFIED LINEAR UNITS AND DROPOUT George E. Dahl a very long time and dropout is likely to only increase training time. Neural networks with rectified, rectified linear units, Bayesian optimization 1. INTRODUCTION Up until a few years ago, most state

Hinton, Geoffrey E.

312

A Microfluidic Rectifier: Anisotropic Flow Resistance at Low Reynolds Numbers Alex Groisman* and Stephen R. Quake  

E-print Network

A Microfluidic Rectifier: Anisotropic Flow Resistance at Low Reynolds Numbers Alex Groisman in microchannels is isotropic. Here we present a micro- fluidic rectifier: a microscopic channel of a special shape of the working fluid, which is a 0.01% aqueous solution of a high molecular weight polymer. The rectifier works

Quake, Stephen R.

313

QUASISYMMETRY AND RECTIFIABILITY OF QUASISPHERES MATTHEW BADGER, JAMES T. GILL, STEFFEN ROHDE, AND TATIANA TORO  

E-print Network

QUASISYMMETRY AND RECTIFIABILITY OF QUASISPHERES MATTHEW BADGER, JAMES T. GILL, STEFFEN ROHDE quasisphere is rectifiable. In particular, we show that for any > 0 integrability of (ess sup1-t is rectifiable. We also establish estimates for the weak quasisymmetry constant of a global K-quasiconformal map

Toro, Tatiana

314

Bipolar or rectified chromatic detection mechanisms? MARCEL J. SANKERALLI and KATHY T. MULLEN  

E-print Network

Bipolar or rectified chromatic detection mechanisms? MARCEL J. SANKERALLI and KATHY T. MULLEN Mc). An alternative possibility is that each cone-opponent response, as well as the luminance response, is rectified). In this study, we use psychophysical noise masking to determine whether the rectified model applies to detection

Mullen, Kathy T.

315

Thermal rectifying effect in two-dimensional anharmonic lattices Jinghua Lan  

E-print Network

Thermal rectifying effect in two-dimensional anharmonic lattices Jinghua Lan Department of Physics September 2006; published 29 December 2006 We study thermal rectifying effect in two-dimensional systems consisting of the Frenkel Kontorva lattice and the Fermi-Pasta-Ulam lattice. It is found that the rectifying

Li, Baowen

316

Edinburgh Research Explorer Distribution of mRNA encoding the inwardly rectifying K+  

E-print Network

Edinburgh Research Explorer Distribution of mRNA encoding the inwardly rectifying K+ channel, BIR1 & Freeman, TC 1995, 'Distribution of mRNA encoding the inwardly rectifying K+ channel, BIR1 in rat tissues) 135-140 Distribution of mRNA encoding the inwardly rectifying K + channel, BIR1 in rat tissues A

MacDonald, Andrew

317

LOW-VOLUME PFC RECTIFIER BASED ON NON-SYMMETRIC MULTI-LEVEL BOOST  

E-print Network

LOW-VOLUME PFC RECTIFIER BASED ON NON-SYMMETRIC MULTI-LEVEL BOOST CONVERTER Behzad Mahdavikhah-phase rectifier with power factor correction (PFC) based on a modified multi level boost converter topology. In comparison with the conventional boost-based systems and other multi-level solutions the new PFC rectifier

Prodiæ, Aleksandar

318

A Novel Three-Phase Rectifier with Reduced THD Gregory Ivensky and Sam Ben-Yaakov  

E-print Network

A Novel Three-Phase Rectifier with Reduced THD Gregory Ivensky and Sam Ben-Yaakov Power Electronics: www.ee.bgu.ac.il/~pel * Correspondig author Abstract- A high power three-phase rectifier that does and by simulation. The proposed rectifier includes 6 uni-directional switches and 24 diodes that are used to realize

319

Asymmetrical Contributions of Subunit Pore Regions to Ion Selectivity in an Inward Rectifier K Channel  

E-print Network

Asymmetrical Contributions of Subunit Pore Regions to Ion Selectivity in an Inward Rectifier K expression of wild-type and mutant heteromultimeric G protein-coupled inward-rectifier K (GIRK) channels consequences between similar mutations in inward-rectifier and voltage-gated K channels, which suggests

Silverman, Scott K.

320

UNIFORM RECTIFIABILITY, CALDERON-ZYGMUND OPERATORS WITH ODD KERNEL, AND QUASIORTHOGONALITY  

E-print Network

UNIFORM RECTIFIABILITY, CALDER´ON-ZYGMUND OPERATORS WITH ODD KERNEL, AND QUASIORTHOGONALITY XAVIER TOLSA Abstract. In this paper we study some questions in connection with uniform rectifiability and the L2 boundedness of Calder´on-Zygmund operators. We show that uniform rectifiability can

Tolsa, Xavier

321

Harmonic Analysis of a Three-Phase Diode Bridge Rectifier based on Sampled-Data Model  

E-print Network

Harmonic Analysis of a Three-Phase Diode Bridge Rectifier based on Sampled-Data Model K. L. Lian presents a time domain method to analyze the three phase rectifier with capacitor output filter Rectifier, Harmonics, Continuous Conduction Mode, Discontinuous Conduction Mode, Steady State Analysis. I

Lehn, Peter W.

322

ASYMPTOTICS FOR DISCRETE WEIGHTED MINIMAL RIESZ ENERGY PROBLEMS ON RECTIFIABLE SETS  

E-print Network

ASYMPTOTICS FOR DISCRETE WEIGHTED MINIMAL RIESZ ENERGY PROBLEMS ON RECTIFIABLE SETS S.V. BORODACHOV1 , D.P. HARDIN2 , AND E. B. SAFF3 Abstract. Given a closed d-rectifiable set A embedded for weighted Riesz potentials on rectifiable sets. Our focus is on the hypersingu- lar case when short range

Saff, E. B.

323

Comparisonof Selected3-Phase SwitchedMode Rectifiers P. Ide; N. Froehleke; H. Grotstollen  

E-print Network

P-25 Comparisonof Selected3-Phase SwitchedMode Rectifiers P. Ide; N. Froehleke; H. Grotstollen rectifiers constrained to unidirectional power flow are inspected and compared with respect to criteria of the standard switched mode boost-type rectifier bridge topology such as a 6-pulse diode bridge, employing

Paderborn, Universität

324

RECTIFIABLE PENCILS OF CONICS Dedicated to my Teacher, Askold Khovanskii, on his 60th birthday  

E-print Network

RECTIFIABLE PENCILS OF CONICS V. TIMORIN Dedicated to my Teacher, Askold Khovanskii, on his 60th be a set of lines in C2 passing through the origin. By a rectifiable L-pencil of curves we mean a family l effectively computable integer). Then any rectifiable L-pencil of conics admits a fractional quadratic

Timorin, Vladlen

325

Efficient Design of Rectifying Antennas for Low Power Detection Vlad Marian  

E-print Network

Efficient Design of Rectifying Antennas for Low Power Detection Vlad Marian 1 , Cyrille Menudier 2, France Abstract -- This article is dedicated to the design of rectifying antenna for wireless energy transfer at 2.45 GHz in the special case of low input power (typically rectifiers present

Paris-Sud XI, Université de

326

Functional Expression and Characterization of G-protein-gated Inwardly Rectifying K+ Channels Containing GIRK3  

E-print Network

Functional Expression and Characterization of G-protein-gated Inwardly Rectifying K+ Channels, USA Received: 13 January 1999/Revised: 2 March 1999 Abstract. The G-protein-gated inwardly rectifying: Potassium channels -- Kir 3.3 -- G --Ion channels Introduction The inward rectifier K+ channels are encoded

Clapham, David E.

327

The First Studies of a Tetrathiafulvalene-s-Acceptor Molecular Rectifier Gregory Ho,[a  

E-print Network

The First Studies of a Tetrathiafulvalene-s-Acceptor Molecular Rectifier Gregory Ho,[a] James R] Aviram and Ratner proposed the concept of a molecular rectifier.[2] They postulated that a covalent donor), when placed between two electrodes can act as a rectifier that preferably passes the current in one

Pezolet, Michel

328

A Multilevel Active Front-End Rectifier With Current Harmonic Compensation Capability  

E-print Network

stresses across each semiconductor [4], in both cases as a rectifier or as multilevel inverter. Moreover oriented for the specific operation as active front-end rectifiers or as multilevel inverters. TypicallyA Multilevel Active Front- End Rectifier With Current Harmonic Compensation Capability Franco

Catholic University of Chile (Universidad Católica de Chile)

329

Ballistic Rectifiers Z. Bennett, M. Koyama, T. Hayafuji, S. Sasa, T. Maemoto, M. Inoue  

E-print Network

Ballistic Rectifiers Z. Bennett, M. Koyama, T. Hayafuji, S. Sasa, T. Maemoto, M. Inoue Nanomaterials Microdevices Research Center Osaka Institute of Technology, Osaka, Japan What is a ballistic to direct current usually using a P-N junction. A ballistic rectifier is a rectifier that relies

330

Optically-controlled extinction ratio and Q-factor tunable silicon microring resonators based on optical forces  

NASA Astrophysics Data System (ADS)

Tunability is a desirable property of microring resonators to facilitate superior performance. Using light to control light, we present an alternative simple approach to tuning the extinction ratio (ER) and Q-factor of silicon microring resonators based on optical forces. We design an opto-mechanical tunable silicon microring resonator consisting of an add-drop microring resonator and a control-light-carrying waveguide (``controlling'' waveguide). One of the two bus waveguides of the microring resonator is a deformable nanostring put in parallel with the ``controlling'' waveguide. The tuning mechanism relies on the optical force induced deflection of suspended nanostring, leading to the change of coupling coefficient of microring and resultant tuning of ER and Q-factor. Two possible geometries, i.e. double-clamped nanostring and cantilever nanostring, are studied in detail for comparison. The obtained results imply a favorable structure with the microring positioned at the end of the cantilever nanostring. It features a wide tuning range of ER from 5.6 to 39.9 dB and Q-factor from 309 to 639 as changing the control power from 0 to 1.4 mW.

Long, Yun; Wang, Jian

2014-06-01

331

Ultrafast optical control using the Kerr nonlinearity in hydrogenated amorphous silicon microcylindrical resonators  

PubMed Central

Microresonators are ideal systems for probing nonlinear phenomena at low thresholds due to their small mode volumes and high quality (Q) factors. As such, they have found use both for fundamental studies of light-matter interactions as well as for applications in areas ranging from telecommunications to medicine. In particular, semiconductor-based resonators with large Kerr nonlinearities have great potential for high speed, low power all-optical processing. Here we present experiments to characterize the size of the Kerr induced resonance wavelength shifting in a hydrogenated amorphous silicon resonator and demonstrate its potential for ultrafast all-optical modulation and switching. Large wavelength shifts are observed for low pump powers due to the high nonlinearity of the amorphous silicon material and the strong mode confinement in the microcylindrical resonator. The threshold energy for switching is less than a picojoule, representing a significant step towards advantageous low power silicon-based photonic technologies. PMID:24097126

Vukovic, N.; Healy, N.; Suhailin, F. H.; Mehta, P.; Day, T. D.; Badding, J. V.; Peacock, A. C.

2013-01-01

332

Silicon photo-multiplier radiation hardness tests with a beam controlled neutron source  

NASA Astrophysics Data System (ADS)

Radiation hardness tests were performed at the Frascati Neutron Generator on silicon Photo-Multipliers that were made of semiconductor photon detectors built from a square matrix of avalanche photo-diodes on a silicon substrate. Several samples from different manufacturers have been irradiated, integrating up to 710 10 1-MeV-equivalent neutrons per cm 2. Detector performance was recorded during the neutron irradiation, and a gradual deterioration of their properties began after an integrated fluence of the order of 10 8 1-MeV-equivalent neutrons per cm 2 was reached.

Angelone, M.; Pillon, M.; Faccini, R.; Pinci, D.; Baldini, W.; Calabrese, R.; Cibinetto, G.; Cotta Ramusino, A.; Malaguti, R.; Pozzati, M.

2010-11-01

333

Large scale low cost fabrication of diameter controllable silicon nanowire arrays.  

PubMed

We report on a novel solution etching method to fabricate vertically aligned aperiodic silicon nanowire (SiNW) arrays. We begin with a simple dewetting process to fabricate a monolayer of well-spaced metal particles in situ on a silicon wafer. The particles function as a sacrificial template to pattern a Ti/Au catalyst film into a metal mesh and the size of particles directly determines the diameter of SiNW. A conventional metal-assisted chemical etching process is then carried out with the obtained metal mesh as a catalyst to realize a vertically aligned SiNW array at a large scale and low cost. PMID:24896291

Sun, Leimeng; Fan, Yu; Wang, Xinghui; Agung Susantyoko, Rahmat; Zhang, Qing

2014-06-27

334

Silicon Photo-Multiplier radiation hardness tests with a beam controlled neutron source  

E-print Network

We report radiation hardness tests performed at the Frascati Neutron Generator on silicon Photo-Multipliers, semiconductor photon detectors built from a square matrix of avalanche photo-diodes on a silicon substrate. Several samples from different manufacturers have been irradiated integrating up to 7x10^10 1-MeV-equivalent neutrons per cm^2. Detector performances have been recorded during the neutron irradiation and a gradual deterioration of their properties was found to happen already after an integrated fluence of the order of 10^8 1-MeV-equivalent neutrons per cm^2.

M. Angelone; M. Pillon; R. Faccini; D. Pinci; W. Baldini; R. Calabrese; G. Cibinetto; A. Cotta Ramusino; R. Malaguti; M. Pozzati

2010-02-18

335

SiC MOSFET Based Single Phase Active Boost Rectifier with Power Factor Correction for Wireless Power Transfer Applications  

SciTech Connect

Wireless Power Transfer (WPT) technology is a novel research area in the charging technology that bridges the utility and the automotive industries. There are various solutions that are currently being evaluated by several research teams to find the most efficient way to manage the power flow from the grid to the vehicle energy storage system. There are different control parameters that can be utilized to compensate for the change in the impedance due to variable parameters such as battery state-of-charge, coupling factor, and coil misalignment. This paper presents the implementation of an active front-end rectifier on the grid side for power factor control and voltage boost capability for load power regulation. The proposed SiC MOSFET based single phase active front end rectifier with PFC resulted in >97% efficiency at 137mm air-gap and >95% efficiency at 160mm air-gap.

Onar, Omer C [ORNL] [ORNL; Tang, Lixin [ORNL] [ORNL; Chinthavali, Madhu Sudhan [ORNL] [ORNL; Campbell, Steven L [ORNL] [ORNL; Miller (JNJ), John M. [JNJ-Miller PLC] [JNJ-Miller PLC

2014-01-01

336

Amorphous Silicon(aSi:H) Thin Film Based Omnidirectional Control Solar Powered Vehicle  

Microsoft Academic Search

Through the paper, our goal is to drive a car with the help of thin film based solar cell. Mechanical and Electrical parts are assembled thereby. The main objective of this project is to collect maximum solar energy from the solar spectrum and use that solar energy to drive the car. Amorphous silicon based thin film solar panel has been

Abdullah Moinuddin; Jony C. Sarker; Akhter Zia

2012-01-01

337

A novel three-phase utility interface minimizing line current harmonics of high-power telecommunications rectifier modules  

Microsoft Academic Search

Based on the combination of a three-phase diode bridge and a DC\\/DC boost converter, a new three-phase three-switch three-level pulsewidth modulated (PWM) rectifier system is developed. It can be characterized by sinusoidal mains current consumption, controlled output voltage, and low-blocking voltage stress on the power transistors. The application could be, e.g., for feeding the DC link of a telecommunications power

Johann W. Kolar; Franz C. Zach

1997-01-01

338

Reduced volume-regulated outwardly rectifying anion channel activity in ventricular myocyte of type 1 diabetic mice  

Microsoft Academic Search

The currents through the volume-regulated outwardly rectifying anion channel (VRAC) were measured in single ventricular myocytes\\u000a obtained from streptozotocin (STZ)-induced diabetic mice, using whole-cell voltage-clamp method. In myocytes from STZ-diabetic\\u000a mice, the density of VRAC current induced by hypotonic perfusion was markedly reduced, compared with that in the cells form\\u000a normal control mice. Video-image analysis showed that the regulatory volume

Shintaro Yamamoto; Kunihiko Ichishima; Tsuguhisa Ehara

2009-01-01

339

A 12 kW three-phase low THD rectifier with high-frequency isolation and regulated DC output  

Microsoft Academic Search

A robust 12 kW rectifier with low THD in the line currents, based on an 18-pulse transformer arrangement with reduced kVA capacities followed by a high-frequency isolation stage is presented in this work. Three full-bridge (buck-based) converters are used to allow galvanic isolation and to balance the dc-link currents, without current sensing or current controller. The topology provides a regulated

F. J. M. de Seixas; I. Barbi

2004-01-01

340

612 IEEE TRANSACTIONS ON POWER ELECTRONICS, VOL. 26, NO. 2, FEBRUARY 2011 Self-Contained Resonant Rectifier for Piezoelectric  

E-print Network

Rectifier for Piezoelectric Sources Under Variable Mechanical Excitation Natan Krihely, Student Member, IEEE the available output power of electrical generators that have a high output capacitance. The proposed rectifier of the resonant rectifier by detecting voltage transitions across the generator. The presented resonant rectifier

341

A rectifying tungsten-molybdenum foil for positron remoderation  

SciTech Connect

We report the use of a layered foil as a positron rectifying device for transmission geometry positron moderation and remoderation, thereby increasing the efficiency of such devices. Positron transmission through foils consisting of a 10 nm W layer on top of a 100 nm Mo foil has been measured. The measurements are compared with similar results for a 100 nm W foil. A strong rectifying effect with a forward to reverse current ratio of more than 10 is observed making this type of well matched layered foils an obvious candidate for positron remoderation. Retarding energy spectra of the transmitted positrons were obtained and measurements of Doppler broadening and surface branching ratios were performed to further characterize the foils. The obtained transmission results again reveal the discrepancy in positron implantation profiles for thin foils between experiments and existing theory. {copyright} {ital 1997 American Institute of Physics.}

Jo/rgensen, L.V.; van Veen, A.; Schut, H. [Interfaculty Reactor Institute, Delft University of Technology, Mekelweg 15, NL-2629 JB Delft (The Netherlands)] [Interfaculty Reactor Institute, Delft University of Technology, Mekelweg 15, NL-2629 JB Delft (The Netherlands); Chevallier, J. [Institute of Physics and Astronomy, Aarhus University, Ny Munkegade, DK-8000 Aarhus C (Denmark)] [Institute of Physics and Astronomy, Aarhus University, Ny Munkegade, DK-8000 Aarhus C (Denmark)

1997-03-01

342

Performance prediction of the wells self-rectifying air turbine  

SciTech Connect

An experimental and analytical study of the effects of geometric and aerodynamic variables on the performance of the Wells self-rectifying axial flow air turbine is presented. Experiments were performed in a unidirectional flow rig. Two approaches to the predictions of the performance of the Wells turbine were described, both of which were based on twodimensional cascade theory and isolated aerofoil data. Finally, comparisons of the predicted results with the experimental results were made.

Raghunathan, S.; Tan, C.P.

1984-08-01

343

Maximum power transfer for full-wave rectifier circuits  

Microsoft Academic Search

With a view to such potential applications as implanted medical instruments, inductive power transfer to weapons, power transfer by means of space reflectors, and power generation in space, an analysis is conducted to ascertain the maximum power transfer conditions for full wave rectifier circuits. The optimum ratio of ac-to-dc voltage output is determined for resistive\\/inductive, resistive\\/capacitive, and resistive\\/inductive\\/capacitive types of

R. J. Arthur

1983-01-01

344

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

DOEpatents

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

Weiner, Kurt H. (San Jose, CA)

2001-01-01

345

Microcomputer controlled soft start of motor  

NASA Astrophysics Data System (ADS)

Improving the starting characteristics of a motor is an important part of the motor control. An intelligent soft starting technique was adopted in the starter and used in the present study because of its many advantages compared with conventional starting processes. The core of the soft starter was a single chip (Atmel 8098), its soul was the software and its control object was a Silicon Controlled Rectifier (SCR). The starter achieved not only current-limit starting, but also closed-loop control with a stator current detection circuit. In conclusion, as a result of digital control, starting characteristic can be conveniently chosen according to the load. In addition the starter is of small size, and starting is smooth and reliable due to current feedback.

Gao, Miao; Wang, Yanpeng; Li, Shian

2005-12-01

346

Donor ionization in size controlled silicon nanocrystals: The transition from defect passivation to free electron generation  

NASA Astrophysics Data System (ADS)

We studied the photoluminescence spectra of silicon and phosphorus co-implanted silica thin films on (100) silicon substrates as a function of isothermal annealing time. The rapid phase segregation, formation, and growth dynamics of intrinsic silicon nanocrystals are observed, in the first 600 s of rapid thermal processing, using dark field mode X-TEM. For short annealing times, when the nanocrystal size distribution exhibits a relatively small mean diameter, formation in the presence of phosphorus yields an increase in the luminescence intensity and a blue shift in the emission peak compared with intrinsic nanocrystals. As the mean size increases with annealing time, this enhancement rapidly diminishes and the peak energy shifts further to the red than the intrinsic nanocrystals. These results indicate the existence of competing pathways for the donor electron, which depends strongly on the nanocrystal size. In samples containing a large density of relatively small nanocrystals, the tendency of phosphorus to accumulate at the nanocrystal-oxide interface means that ionization results in a passivation of dangling bond (Pb-centre) type defects, through a charge compensation mechanism. As the size distribution evolves with isothermal annealing, the density of large nanocrystals increases at the expense of smaller nanocrystals, through an Ostwald ripening mechanism, and the majority of phosphorus atoms occupy substitutional lattice sites within the nanocrystals. As a consequence of the smaller band-gap, ionization of phosphorus donors at these sites increases the free carrier concentration and opens up an efficient, non-radiative de-excitation route for photo-generated electrons via Auger recombination. This effect is exacerbated by an enhanced diffusion in phosphorus doped glasses, which accelerates silicon nanocrystal growth.

Crowe, I. F.; Papachristodoulou, N.; Halsall, M. P.; Hylton, N. P.; Hulko, O.; Knights, A. P.; Yang, P.; Gwilliam, R. M.; Shah, M.; Kenyon, A. J.

2013-01-01

347

Rapid thermal processing of high-efficiency silicon solar cells with controlled in-situ annealing  

SciTech Connect

Silicon solar cell efficiencies of 17.1%, 16.4%, 14.8%, and 14.9% have been achieved on FZ, Cz, multicrystalline (mc-Si), and dendritic web (DW) silicon, respectively, using simplified, cost-effective rapid thermal processing (RTP). These represent the highest reported efficiencies for solar cells processed with simultaneous front and back diffusion with no conventional high-temperature furnace steps. Appropriate diffusion temperature coupled with the added in-situ anneal resulted in suitable minority-carrier lifetime and diffusion profiles for high-efficiency cells. The cooling rate associated with the in-situ anneal can improve the lifetime and lower the reverse saturation current density (J{sub 0}), however, this effect is material and base resistivity specific. PECVD antireflection (AR) coatings provided low reflectance and efficient front surface and bulk defect passivation. Conventional cells fabricated on FZ silicon by furnace diffusions and oxidations gave an efficiency of 18.8% due to greater short wavelength response and lower J{sub 0}.

Doshi, P.; Rohatgi, A.; Ropp, M.; Chen, Z. [Georgia Institute of Technology, Atlanta, GA (United States). Univ. Center of Excellence for Photovoltaics Research and Education; Ruby, D. [Sandia National Labs., Albuquerque, NM (United States); Meier, D.L. [EBARA Solar, Inc., Large, PA (United States)

1995-01-01

348

Single-Phase Active Boost Rectifier with Power Factor Correction for Wireless Power Transfer Applications  

SciTech Connect

Wireless Power Transfer (WPT) technology is a novel research area in the charging technology that bridges utility and the automotive industries. There are various solutions that are currently being evaluated by several research teams to find the most efficient way to manage the power flow from the grid to the vehicle energy storage system. There are different control parameters that can be utilized to compensate for the change in the impedance. To understand the power flow through the system this paper presents a novel approach to the system model and the impact of different control parameters on the load power. The implementation of an active front-end rectifier on the grid side for power factor control and voltage boost capability for load power regulation is also discussed.

Chinthavali, Madhu Sudhan [ORNL] [ORNL; Onar, Omer C [ORNL] [ORNL; Miller, John M [ORNL] [ORNL; Tang, Lixin [ORNL] [ORNL

2013-01-01

349

Electrical derivative characteristics of InGaAsP buried heterostructure lasers with a rectifying contact  

SciTech Connect

Results of a study of the electrical derivative chartacteristics of 1.3-..mu..m InGaAsP buried heterostructure lasers with rectifying (nonlinear) electrical contacts are presented. A physical device model and an equivalent circuit model, including a metal-semiconductor contact, have been developed. This model is also appropriate to light emitting diodes and photodiodes. Solutions for the electrical derivative characteristics, dv/di and i dv/di vs i, of the equivalent circuit model are obtained and used to calculate the characteristics of 1.3-..mu..m InGaAsP buried heterostructure lasers both with and without a rectifying contact. The calculated electrical derivative characteristics are compared to measured data for our lasers. Excellent agreement between measured and modeled characteristics is obtained and the analysis is shown to be useful for extracting detailed metal-semiconductor and p-n junction characteristics with high accuracy. The physical basis for nonlinear contacts to optoelectronic devices made from relatively wide band-gap semiconductors such as InP and InGaAsP is described. The results of this study are useful for characterization, modeling, failure mode analysis, and process control improvement of these devices.

Wright, P.D.

1987-03-01

350

An Adaptive Reconfigurable Active Voltage Doubler/Rectifier for Extended-Range Inductive Power Transmission  

PubMed Central

We present an adaptive reconfigurable active voltage doubler (VD)/rectifier (REC) (VD/REC) in standard CMOS, which can adaptively change its topology to either a VD or a REC by sensing the output voltage, leading to more robust inductive power transmission over an extended range. Both active VD and REC modes provide much lower dropout voltage and far better power conversion efficiency (PCE) compared to their passive counterparts by adopting offset-controlled high-speed comparators that drive the rectifying switches at proper times in the high-frequency band. We have fabricated the active VD/REC in a 0.5-m 3-metal 2-poly CMOS process, occupying 0.585 mm2 of chip area. In an exemplar setup, VD/REC extended the power transmission range by 33% (from 6 to 8 cm) in relative coil distance and 41.5% (from 53 to 75) in relative coil orientation compared to using the REC alone. While providing 3.1-V dc output across a 500-? load from 2.15- (VD) and 3.7-V (REC) peak ac inputs at 13.56 MHz, VD/REC achieved measured PCEs of 70% and 77%, respectively. PMID:24633369

Lee, Hyung-Min; Ghovanloo, Maysam

2014-01-01

351

Microscopic control of $^{29}$Si nuclear spins near phosphorus donors in silicon  

E-print Network

Dynamic nuclear polarization of $^{29}$Si nuclei in resolved lattice sites near the phosphorus donors in natural silicon of has been created using the Overhauser and solid effects. Polarization has been observed as a pattern of well separated holes and peaks in the electron spin resonance line of the donor. The Overhauser effect in ESR hole burning experiments was used to manipulate the polarization of $^{29}$Si spins at ultra low (100-500 mK) temperatures and in high magnetic field of 4.6 T. Extremely narrow holes of 15 mG width were created after several seconds of pumping.

Jrvinen, J; Ahokas, J; Sheludyakov, S; Vainio, O; Lehtonen, L; Vasiliev, S; Fujii, Y; Mitsudo, S; Mizusaki, T; Gwak, M; Lee, SangGap; Lee, Soonchil; Vlasenko, L

2014-01-01

352

High reliability megawatt transformer/rectifier  

NASA Technical Reports Server (NTRS)

The goal of the two phase program is to develop the technology and design and fabricate ultralightweight high reliability DC to DC converters for space power applications. The converters will operate from a 5000 V dc source and deliver 1 MW of power at 100 kV dc. The power weight density goal is 0.1 kg/kW. The cycle to cycle voltage stability goals was + or - 1 percent RMS. The converter is to operate at an ambient temperature of -40 C with 16 minute power pulses and one hour off time. The uniqueness of the design in Phase 1 resided in the dc switching array which operates the converter at 20 kHz using Hollotron plasma switches along with a specially designed low loss, low leakage inductance and a light weight high voltage transformer. This approach reduced considerably the number of components in the converter thereby increasing the system reliability. To achieve an optimum transformer for this application, the design uses four 25 kV secondary windings to produce the 100 kV dc output, thus reducing the transformer leakage inductance, and the ac voltage stresses. A specially designed insulation system improves the high voltage dielectric withstanding ability and reduces the insulation path thickness thereby reducing the component weight. Tradeoff studies and tests conducted on scaled-down model circuits and using representative coil insulation paths have verified the calculated transformer wave shape parameters and the insulation system safety. In Phase 1 of the program a converter design approach was developed and a preliminary transformer design was completed. A fault control circuit was designed and a thermal profile of the converter was also developed.

Zwass, Samuel; Ashe, Harry; Peters, John W.

1991-01-01

353

Silicon nanowires with controlled sidewall profile and roughness fabricated by thin-film dewetting and metal-assisted chemical etching.  

PubMed

This paper presents a non-lithographic approach to generate wafer-scale single crystal silicon nanowires (SiNWs) with controlled sidewall profile and surface morphology. The approach begins with silver (Ag) thin-film thermal dewetting, gold (Au) deposition and lift-off to generate a large-scale Au mesh on Si substrates. This is followed by metal-assisted chemical etching (MacEtch), where the Au mesh serves as a catalyst to produce arrays of smooth Si nanowires with tunable taper up to 13. The mean diameter of the thus fabricated SiNWs can be controlled to range from 62 to 300 nm with standard deviations as small as 13.6 nm, and the areal coverage of the wire arrays can be up to 46%. Control of the mean wire diameter is achieved by controlling the pore diameter of the metallic mesh which is, in turn, controlled by adjusting the initial thin-film thickness and deposition rate. To control the wire surface morphology, a post-fabrication roughening step is added to the approach. This step uses Au nanoparticles and slow-rate MacEtch to produce rms surface roughness up to 3.6 nm. PMID:23644697

Azeredo, B P; Sadhu, J; Ma, J; Jacobs, K; Kim, J; Lee, K; Eraker, J H; Li, X; Sinha, S; Fang, N; Ferreira, P; Hsu, K

2013-06-01

354

Performance of Thin-Window Silicon Drift Detectors  

SciTech Connect

Several sets of hexagonal Silicon Drift Detector (SDD) arrays were produced at BNL and by a commercial vendor, KETEK. Each array consists of 14 independent detectors (pixels) and two additional test pixels at two of the corners. The side of the detector upon which the X-ray radiation is incident (window side) has a thin junction covering the entire active area. The opposite side (device side) contains a drift-field electrode structure in the form of a hexagonal spiral and an electron collecting anode. There are 4 guard rings surrounding the 14-pixel array area on both sides of the detector. Within each array, 7 of the pixels have an aluminum field plate - interrupted spirals that stabilize the electric potential under the Si-SiO2 interface, while the other 7 do not. The drift field in the silicon volume is controlled by three biases: one is applied to a rectifying contact, one to the detector entrance window, and the third to a contact on the outer portion of the spiral common to all pixels in the array. Some arrays have been newly measured in NSLS beam line U3C at BNL. The complete assemblies were installed in the vacuum and cooled to ?27 C. During this run, spectra for energies ranging between 400 and 900 eV were collected in several pixels, some with field plates and others without. The detailed testing results of several arrays are reported here.

Carini, , G.A.; Chen, W.; De Geronimo, G.; Fried, J.; Gaskin, J.A.; Keister; J.W.; Li, Z.; Ramsey, B.D.; Rehak, P.; Siddons, D.P.

2008-10-20

355

Silicone metalization  

DOEpatents

A system for providing metal features on silicone comprising providing a silicone layer on a matrix and providing a metal layer on the silicone layer. An electronic apparatus can be produced by the system. The electronic apparatus comprises a silicone body and metal features on the silicone body that provide an electronic device.

Maghribi, Mariam N. (Livermore, CA); Krulevitch, Peter (Pleasanton, CA); Hamilton, Julie (Tracy, CA)

2006-12-05

356

Silicone metalization  

DOEpatents

A system for providing metal features on silicone comprising providing a silicone layer on a matrix and providing a metal layer on the silicone layer. An electronic apparatus can be produced by the system. The electronic apparatus comprises a silicone body and metal features on the silicone body that provide an electronic device.

Maghribi, Mariam N. (Livermore, CA); Krulevitch, Peter (Pleasanton, CA); Hamilton, Julie (Tracy, CA)

2008-12-09

357

Controlling the shape and gap width of silicon electrodes using local anodic oxidation and anisotropic TMAH wet etching  

NASA Astrophysics Data System (ADS)

A simple method for fabricating silicon electrodes with various shapes and gap widths was designed using the special properties of anisotropic tetramethylammonium hydroxide (TMAH) wet etching and local anodic oxidation (LAO). A statistical system was used for the optimization of the parameters of the LAO process to facilitate a better understanding and precise analysis of the process. Analyses of the interaction effects among the significant factors of LAO showed that the relative humidity and applied voltage were interdependent. They had the strongest interaction effect on the dimensions of the oxide mask. TMAH with a concentration of 25% was used as an etchant solution in (1?0?0) silicon with a rectangular oxide mask. The observed undercutting at convex corners, tip shape of emitters and gap widths of electrodes were exactly consistent with theoretical studies. Combination of the LAO method and anisotropic TMAH wet etching was successfully used to fabricate Si nano-gap electrodes. This fabrication method of sharp and round tip emitters was simple, controllable and faster than common techniques. These results indicate that the method can be a new approach for studying the electrical properties of nano-gap electrodes.

Rouhi, Jalal; Mahmud, Shahrom; Derita Hutagalung, Sabar; Naderi, Nima; Kakooei, Saeid; Johar Abdullah, Mat

2012-06-01

358

InAs=InGaP=GaAs heterojunction power Schottky rectifiers  

E-print Network

InAs=InGaP=GaAs heterojunction power Schottky rectifiers A. Chen, M. Young and J.M. Woodall A low-matched InGaP on GaAs, to make a high-temperature power rectifier. The LT molecular beam epitaxy technique enables the formation of an abrupt interface between InAs and InGaP. This heterojunction rectifier

Woodall, Jerry M.

359

SQUARE FUNCTIONS AND UNIFORM RECTIFIABILITY VASILEIOS CHOUSIONIS, JOHN GARNETT, TRIET LE, AND XAVIER TOLSA  

E-print Network

SQUARE FUNCTIONS AND UNIFORM RECTIFIABILITY VASILEIOS CHOUSIONIS, JOHN GARNETT, TRIET LE is uniformly n-rectifiable if and only if for any ball B(x0, R) centered at supp(�), R 0 xB(x0,R) �(B(x, r)) rn - �(B(x, 2r)) (2r)n 2 d�(x) dr r c Rn . Other characterizations of uniform n-rectifiability in terms

Tolsa, Xavier

360

RECTIFIABILITY VIA A SQUARE FUNCTION AND PREISS' XAVIER TOLSA AND TATIANA TORO  

E-print Network

RECTIFIABILITY VIA A SQUARE FUNCTION AND PREISS' THEOREM XAVIER TOLSA AND TATIANA TORO Abstract)E) > 0 for Hn -a.e. x E. In this paper it is shown that E is n-rectifiable if and only if 1 0 Hn (B(x, r measures are also proved. 1. Introduction A set E Rd is called n-rectifiable if there are Lipschitz maps

Tolsa, Xavier

361

SQUARE FUNCTIONS AND UNIFORM RECTIFIABILITY VASILEIOS CHOUSIONIS, JOHN GARNETT, TRIET LE, AND XAVIER TOLSA  

E-print Network

SQUARE FUNCTIONS AND UNIFORM RECTIFIABILITY VASILEIOS CHOUSIONIS, JOHN GARNETT, TRIET LE is uniformly n-rectifiable if and only if for any ball B(x0, R) centered at supp(µ), R 0 xB(x0,R) µ(B(x, r)) rn - µ(B(x, 2r)) (2r)n 2 dµ(x) dr r c Rn . Other characterizations of uniform n-rectifiability in terms

Tolsa, Xavier

362

A novel passive waveshaping method for single-phase diode rectifiers  

Microsoft Academic Search

A novel passive waveshaping method for single-phase diode rectifiers is presented. It is shown that application of the proposed method maintains high-input power factor, lowers rectifier current stresses, and lowers the volt-ampere (VA) rating of the associated reactive components as compared to the standard diode rectifier. Relevant input and output current waveforms, component ratings, and power factor values are derived.

A. R. Prasad; P. D. Ziogas; S. Manias

1990-01-01

363

Development of design model for a rectifier in GAX absorption heat pump systems  

SciTech Connect

This paper develops a model for design of a rectifier in generator-absorber heat exchanger (GAX) heat pump systems with an ammonia-water solution pair. The objectives of this paper are to provide further understanding of the rectification process in ammonia-water systems and serve as a design tool for the rectifier using a stable computation method. Simultaneous heat and mass transfer analysis is performed for the rectification process. Three different geometric configurations of the rectifier, namely, vertical fluted tube, confined cross flow with fluted tube, and coiled smooth tube, are considered in this paper. The effects of the temperature difference between interface and bulk vapor and heat transfer coefficients in each region on the rectifier size are investigated. The importance of the composition of rectifying vapor, z, is studied. The results show that the temperature difference between the interface and the bulk vapor region should be minimized to obtain a rectifier of small size and a high coefficient of performance (COP). During the rectification process, the composition of rectifying vapor should be lower than the liquid concentration, i.e., z < x{sub l}. The heat transfer coefficient in the vapor region has a much more dominant effect on the rectifier size than that in the liquid and the coolant regions. Mass transfer has a more significant effect on the rectifier size than heat transfer.

Kang, Y.T.; Chen, W.; Christensen, R.N. [Ohio State Univ., Columbus, OH (United States). Dept. of Mechanical Engineering

1996-11-01

364

Influence on the rectifiers of rotor losses in high-speed permanent magnet synchronous alternator  

NASA Astrophysics Data System (ADS)

This article deals with the rotor losses in the high-speed permanent magnet (PM) synchronous alternator for distributed power generation system. Specifically, the influence of rectifiers on the rotor losses is investigated. On the basis of analytical field analysis and two-dimensional finite element analysis, this article predicts the flux harmonics and rotor losses in the PM alternator considering the rectifier load. The prototype machine with the rectifier load has been fabricated and tested. Moreover, the difference of rotor losses between the high-speed alternator with and without the rectifier is made quantitatively clear in this work.

Jang, Seok-Myeong; Cho, Han-Wook; Jeong, Yeon-Ho

2006-04-01

365

Rectified momentum transport for a kicked Bose-Einstein Condensate  

E-print Network

We report the experimental observation of rectified momentum transport for a Bose-Einstein Condensate kicked at the Talbot time (quantum resonance) by an optical standing wave. Atoms are initially prepared in a superposition of the 0 and -2*hbar*kl momentum states using an optical pi/2 pulse. By changing the relative phase of the superposed states, a momentum current in either direction along the standing wave may be produced. We offer an interpretation based on matter wave interference, showing that the observed effect is uniquely quantum.

Mark Sadgrove; Munekazu Horikoshi; Tetsuo Sekimura; Ken'ichi Nakagawa

2007-06-12

366

Surface polarity control to reinforce dopant adhesion in laser doping of textured silicon  

NASA Astrophysics Data System (ADS)

Increasing energy conversion efficiency without any extra cost is required for crystalline silicon (c-Si) solar cells. Laser doping (LD) can meet these requirements because it can be performed in an ambient atmosphere at room temperature. In this study, spin-coated phosphorus silicate glass (PSG) was formed on textured c-Si as a precursor for LD. We found that after LD, the reinforcement of the interface between PSG and the Si surface improved the photovoltaic characteristics Voc and Jsc. The interface was reinforced by changing the c-Si surface from hydrophobic to hydrophilic before spin coating. The reinforced interface led to a reduction in the number of surface voids and an enhancement of the transfer of dopant atoms.

Nishimura, Hideki; Okamura, Takanori; Yamamoto, Yuki; Fuyuki, Takashi

2014-05-01

367

Novel mini-reactor of silicone oil droplets for synthesis of morphology-controlled polymer particles.  

PubMed

Inside spaces of emulsion droplets can be used as mini-reactors for material synthesis. The novel application of sol-gel derived silicone oil droplets as mini-reactors was examined for the case of polymerization of styrene (St) and comonomers with the oil-soluble initiator 2,2'-azobis(2,4-dimethylvaleronitrile). Polydimethylsiloxane (PDMS) droplets prepared from dimethylsiloxane were used as the mini-reactors, in which the polymerization of St without comonomers was first conducted. In the polymerization, the St/PDMS volume ratio was varied from 0.025 to 0.10. After the polymerization, each PDMS droplet contained a polystyrene (PSt) particle. The St/PDMS ratio of 0.05 enabled the synthesis of micrometer-sized, spherical PSt particles with low polydispsersity. Copolymerization of St with comonomers having hydrophilic groups deformed the spherical shape of particles to lens-like or disk-like morphologies that were obtained with acrylic acid or sodium 4-styrene sulfonate, respectively. In another copolymerization, with divinylbenzene used as a cross-linker, hemispherical polymer particles were formed. To diversify the particle morphologies further, the proposed mini-reactor synthesis was combined with the recently proposed silicone oil droplet templating method (Ohta et al., 2012). Around the PDMS droplets containing a polymer particle, polymeric shells with a depression were successfully formed with the proposed method. The remaining PDMS oil inside the polymeric shells was extracted with ethanol, which caused hemispherical polymeric bowl-shaped capsules having a protrusion on the inside. PMID:23194249

Nagao, Daisuke; Ohta, Tatsuya; Ishii, Haruyuki; Imhof, Arnout; Konno, Mikio

2012-12-21

368

A Novel Solid-State Thermal Rectifier Based On Reduced Graphene Oxide  

NASA Astrophysics Data System (ADS)

Recently, manipulating heat transport by phononic devices has received significant attention, in which phonon - a heat pulse through lattice, is used to carry energy. In addition to heat control, the thermal devices might also have broad applications in the renewable energy engineering, such as thermoelectric energy harvesting. Elementary phononic devices such as diode, transistor and logic devices have been theoretically proposed. In this work, we experimentally create a macroscopic scale thermal rectifier based on reduced graphene oxide. Obvious thermal rectification ratio up to 1.21 under 12 K temperature bias has been observed. Moreover, this ratio can be enhanced further by increasing the asymmetric ratio. Collectively, our results raise the exciting prospect that the realization of macroscopic phononic device with large-area graphene based materials is technologically feasible, which may open up important applications in thermal circuits and thermal management.

Tian, He; Xie, Dan; Yang, Yi; Ren, Tian-Ling; Zhang, Gang; Wang, Yu-Feng; Zhou, Chang-Jian; Peng, Ping-Gang; Wang, Li-Gang; Liu, Li-Tian

2012-07-01

369

A novel solid-state thermal rectifier based on reduced graphene oxide.  

PubMed

Recently, manipulating heat transport by phononic devices has received significant attention, in which phonon--a heat pulse through lattice, is used to carry energy. In addition to heat control, the thermal devices might also have broad applications in the renewable energy engineering, such as thermoelectric energy harvesting. Elementary phononic devices such as diode, transistor and logic devices have been theoretically proposed. In this work, we experimentally create a macroscopic scale thermal rectifier based on reduced graphene oxide. Obvious thermal rectification ratio up to 1.21 under 12?K temperature bias has been observed. Moreover, this ratio can be enhanced further by increasing the asymmetric ratio. Collectively, our results raise the exciting prospect that the realization of macroscopic phononic device with large-area graphene based materials is technologically feasible, which may open up important applications in thermal circuits and thermal management. PMID:22826801

Tian, He; Xie, Dan; Yang, Yi; Ren, Tian-Ling; Zhang, Gang; Wang, Yu-Feng; Zhou, Chang-Jian; Peng, Ping-Gang; Wang, Li-Gang; Liu, Li-Tian

2012-01-01

370

Cell technology: Advanced silicon sheet  

NASA Technical Reports Server (NTRS)

The Flat-plate Solar Array (FSA)-sponsored Fourth Silicon Stress/Strain Workshop reviewed, coordinated, and assessed the progress in understanding and controlling stress and strain during the crystal growth of silicon ribbons. dislocation electrical activity and limits on solar cell efficiency, and on studying the effects of dopants on EFG characteristics. Work on silicon for high-efficiency solar cells, stress-strain relationships in silicon ribbon, and high temperature deformation of dendritic web ribbon was also discussed.

Morrison, Andrew D.

1986-01-01

371

Inward-rectifying K+ channels in guard cells provide a mechanism for low-affinity K+ uptake.  

PubMed Central

The molecular mechanisms by which higher plant cells take up K+ across the plasma membrane (plasmalemma) remain unknown. Physiological transport studies in a large number of higher plant cell types, including guard cells, have suggested that at least two distinct types of K(+)-uptake mechanisms exist, permitting low-affinity and high-affinity K+ accumulation, respectively. Recent patch clamp studies have revealed the presence of inward-conducting (inward-rectifying) K+ channels in the plasma membrane of higher plant cells. Research on guard cells has suggested that these K+ channels provide a major pathway for proton pump-driven K+ uptake during stomatal opening. In the present study the contribution of inward-rectifying K+ channels to higher plant cell K+ uptake was investigated by examining kinetic properties of guard cell K+ channels in Vicia faba in response to changes in the extracellular K+ concentration. Increasing the extracellular K+ concentration in the range from 0.3 mM to 11.25 mM led to enhancement of inward K+ currents and changes in current-voltage characteristics of K+ channels. The increase in K+ conductance as a function of the extracellular K+ concentration revealed a K(+)-equilibrium dissociation constant (Km) of approximately 3.5 mM, which suggests that inward-rectifying K+ channels can function as a molecular mechanism for low-affinity K+ uptake. Lowering the extracellular K+ concentration in the range from 11 mM to 1 mM induced negative shifts in the activation potential of K+ channels, such that these channels function as a K+ sensor, permitting only K+ uptake. At low extracellular K+ concentrations of 0.3 mM K+, inward-rectifying K+ channels induce hyperpolarization. Results from the present study suggest that inward-rectifying K+ channels constitute an essential molecular mechanism for plant nutrition and growth control by providing a K(+)-sensing and voltage-dependent pathway for low-affinity K+ uptake into higher plant cells and additionally by contributing to plasma membrane potential regulation. PMID:1763075

Schroeder, J I; Fang, H H

1991-01-01

372

Self-rectifying electron beam melter for pendant-drop containerless processing  

NASA Technical Reports Server (NTRS)

A self-rectifying electron beam melting technique is described. Utilizing an ac power supply, in contrast to the more usual dc supply, the in situ self-rectifying approach offers a simple and very inexpensive means of producing metallic pendant drops for use in containerless melt-processing experiments.

Pyun, D. S.; Collings, E. W.

1993-01-01

373

A MOSFET resonant synchronous rectifier for high-frequency DC\\/DC converters  

Microsoft Academic Search

A resonant synchronous rectifier which combines the fast switching of Schottky diodes with low conduction drop of MOSFET devices is discussed. The MOSFET devices are driven in a resonant fashion by the power circuit, resulting in partial recovery of the energy stored in the parasitic capacitances. Power loss in the resonant synchronous rectifier is determined as a function of various

Wojciech A. Tabisz; Fred C. Lee; Dan Y. Chen

1990-01-01

374

High Performance Rectifier with Wide Speed Range for Direct-Drive Wind Energy System  

Microsoft Academic Search

A high performance rectifier with a novel structural and wide speed range for direct-drive wind energy system has been investigated and design. The utilization rate and efficiency of low wind are critical focus for wind energy system, in the form of ultimate output dc voltage as the optimum object, a traditional full-bridge PWM rectifier and a boost circuit for the

Hongyang Zhang; Changbao Fan; Renyuan Tang; Jianguang Zhu

2010-01-01

375

A Simple Inverter for Arc-Welding Machines With Current Doubler Rectifier  

Microsoft Academic Search

This letter proposes a novel inverter scheme for arc-welding machines. The output rectifier replaced by a current double rectifier can reduce output ripple current effectively. Therefore, the lower inductance of the inductors can be used to prevent larger voltage spikes that occur during commutation. In comparison with that in the conventional scheme, each inductor's current in the proposed scheme is

Jian-Min Wang; Sen-Tung Wu; Shang-Chin Yen; Huang-Jen Chiu

2011-01-01

376

Porosity control in metal-assisted chemical etching of degenerately doped silicon nanowires.  

PubMed

We report the fabrication of degenerately doped silicon (Si) nanowires of different aspect ratios using a simple, low-cost and effective technique that involves metal-assisted chemical etching (MacEtch) combined with soft lithography or thermal dewetting metal patterning. We demonstrate sub-micron diameter Si nanowire arrays with aspect ratios as high as 180:1, and present the challenges in producing solid nanowires using MacEtch as the doping level increases in both p- and n-type Si. We report a systematic reduction in the porosity of these nanowires by adjusting the etching solution composition and temperature. We found that the porosity decreases from top to bottom along the axial direction and increases with etching time. With a MacEtch solution that has a high [HF]:[H(2)O(2)] ratio and low temperature, it is possible to form completely solid nanowires with aspect ratios of less than approximately 10:1. However, further etching to produce longer wires renders the top portion of the nanowires porous. PMID:22781120

Balasundaram, Karthik; Sadhu, Jyothi S; Shin, Jae Cheol; Azeredo, Bruno; Chanda, Debashis; Malik, Mohammad; Hsu, Keng; Rogers, John A; Ferreira, Placid; Sinha, Sanjiv; Li, Xiuling

2012-08-01

377

Vacancies in defect-free zone of point-defect-controlled CZ silicon observed by low-temperature ultrasonic measurements  

Microsoft Academic Search

The low-temperature ultrasonic measurements are performed for the direct observation of the vacancies in Czochralski-grown (CZ-grown) silicon crystal. The elastic softening similar to that we recently found for the floating-zone-grown (FZ-grown) silicon crystals is observed also for the vacancy-rich region of the defect-free zone (DFZ) in the CZ silicon crystal. We further uncover that both of the interstitial-rich region in

Hiroshi Yamada-Kaneta; Terutaka Goto; Yasuhiro Saito; Yuichi Nemoto; Koji Sato; Koichi Kakimoto; Shintaro Nakamura

2006-01-01

378

Input Power Quality Improvement in Switched Reluctance Motor Drive using Minnesota Rectifier  

NASA Astrophysics Data System (ADS)

This paper deals with an input power quality improvement in a midpoint converter based switched reluctance motor (SRM) drive at ac mains using Minnesota rectifier. Normally a midpoint converter is used as a power converter for SRM drive. Conventionally three phase ac mains fed bridge rectifier is used as a dc source to feed this power converter which produces high content of harmonics at ac mains with a very low power factor. The proposed Minnesota rectifier with a midpoint converter fed SRM drive improves the power factor at ac mains with low current harmonics. This method provides constant dc link voltage and balanced capacitor voltages of the midpoint converter. The Minnesota rectifier fed SRM drive is modelled and its performance is simulated in Matlab/Simulink environment. The performance of Minnesota rectifier is compared with a conventional bridge topology for SRM drive to demonstrate improved power quality at ac mains.

Singh, B.; Rajesh, M.

2013-09-01

379

Controlled Synthesis of Millimeter-Long Silicon Nanowires with Uniform Electronic Properties  

PubMed Central

We report the nanocluster-catalyzed growth of ultra-long and highly-uniform single-crystalline silicon nanowires (SiNWs) with millimeter-scale lengths and aspect ratios up to ca. 100,000. The average SiNW growth rate using disilane (Si2H6) at 400 C was 31 m/min, while the growth rate determined for silane (SiH4) reactant under similar growth conditions was 130 times lower. Transmission electron microscopy studies of millimeter-long SiNWs with diameters of 2080 nm show that the nanowires grow preferentially along the <110> direction independent of diameter. In addition, ultra-long SiNWs were used as building blocks to fabricate one-dimensional arrays of field-effect transistors (FETs) consisting of ca. 100 independent devices per nanowire. Significantly, electrical transport measurements demonstrated that the millimeter-long SiNWs had uniform electrical properties along the entire length of wires, and each device can behave as a reliable FET with an on-state current, threshold voltage, and transconductance values (average 1 standard deviation) of 1.8 0.3 A, 6.0 1.1 V, 210 60 nS, respectively. Electronically-uniform millimeter-long SiNWs were also functionalized with monoclonal antibody receptors, and used to demonstrate multiplexed detection of cancer marker proteins with a single nanowire. The synthesis of structurally- and electronically-uniform ultra-long SiNWs may open up new opportunities for integrated nanoelectronics, and could serve as unique building blocks linking integrated structures from the nanometer through millimeter length scales. PMID:18710294

Park, Won Il; Zheng, Gengfeng; Jiang, Xiaocheng; Tian, Bozhi; Lieber, Charles M.

2009-01-01

380

542 IEEE TRANSACTIONS ON POWER ELECTRONICS, VOL. 19, NO. 2, MARCH 2004 Analysis and Modeling of a Voltage Doubler Rectifier  

E-print Network

of a Voltage Doubler Rectifier Fed by a Piezoelectric Transformer Gregory Ivensky, Moshe Shvartsas, and Shmuel--conditions. Considering the primary objective of obtaining a high output voltage, a voltage doubler rectifier will be the preferred choice. The simplest voltage doubler rectifier has a nonsymmetrical half-wave topology with one

381

Rectified Catadioptric Stereo Sensors Joshua Gluckman, Member, IEEE Computer Society, and Shree K. Nayar, Senior Member, IEEE  

E-print Network

Rectified Catadioptric Stereo Sensors Joshua Gluckman, Member, IEEE Computer Society, and Shree K novel catadioptric sensors that use mirrors to produce rectified stereo images. The scan- line be satisfied to obtain rectified stereo images with a single camera. Then, we discuss in detail the use of both

Nayar, Shree K.

382

HIGH EFFICIENCY 3-PHASE CMOS RECTIFIER WITH STEP UP AND REGULATED OUTPUT VOLTAGE -DESIGN AND SYSTEM ISSUES FOR MICRO GENERATION  

E-print Network

HIGH EFFICIENCY 3-PHASE CMOS RECTIFIER WITH STEP UP AND REGULATED OUTPUT VOLTAGE - DESIGN related to the monolithic integration of a 3-phase AC to DC low voltage, low power rectifier for 3-phase micro- generator, a stand alone 3-phase AC to DC integrated rectifier, and an output voltage conditioner

Paris-Sud XI, Université de

383

Supralinear Summation of Synaptic Inputs by an Invertebrate Neuron: Dendritic Gain Is Mediated by an "Inward Rectifier"  

E-print Network

by an "Inward Rectifier" K Current Ralf Wessel,1 William B. Kristan Jr,2 and David Kleinfeld1 Departments of 1 that depends on the external [K ]. These features are those of an "inward rectifier," Kir. Microsurgery words: dendritic processing; leech; inward rectifier; su- pralinear summation; model; synaptic inputs

Wessel, Ralf

384

Seventeen years of the ``La Clapie`re'' landslide evolution analysed from ortho-rectified aerial photographs  

E-print Network

Seventeen years of the ``La Clapie`re'' landslide evolution analysed from ortho-rectified aerial to ortho-rectify three aerial photographs acquired between 1983 and 1999. Measurements, made from these ortho-rectified images, show that the average velocity of the landslide was of 1.7 cm/day, with the rate

Delacourt, Christophe

385

Power efficient multi-stage CMOS rectifier design for UHF RFID tags$ Shu-Yi Wong, Chunhong Chen n  

E-print Network

Power efficient multi-stage CMOS rectifier design for UHF RFID tags$ Shu-Yi Wong, Chunhong Chen n March 2011 Available online 17 March 2011 Keywords: RFID Low power Differential-drive rectifier a b s t r a c t Power efficiency of a UHF rectifier circuit, which is part of long-range IC-based passive

Chen, Chunhong

386

High-Efficiency Harmonically-Terminated Rectifier for Wireless Powering Applications Michael Roberg, Erez Falkenstein and Zoya Popovic  

E-print Network

High-Efficiency Harmonically-Terminated Rectifier for Wireless Powering Applications Michael Roberg of Colorado, Boulder, CO, 80309-0425 Abstract-In wireless powering, the rectifier efficiency has a large rectifier design based on reduced conduction angle power amplifier theory. The analysis for an ideal

Popovic, Zoya

387

JP2.12 AN ANALYTIC MODEL OF THE VERTICAL CARBON DIOXIDE RECTIFIER Vincent E. Larson1  

E-print Network

JP2.12 AN ANALYTIC MODEL OF THE VERTICAL CARBON DIOXIDE RECTIFIER EFFECT Vincent E. Larson1 , Hans a trun- cated sinusoidal appearance reminiscent of a rectified electrical alternating current (Heimann et the ground and a deficit aloft. The rectifier effect is important in part because of its effect on inverse

388

InAsGaPInGaP high-temperature power Schottky rectifier and J. M. Woodall  

E-print Network

InAs?GaP?InGaP high-temperature power Schottky rectifier A. Chena) and J. M. Woodall Department February 2004 An InAs/GaP/InGaP rectifier has been fabricated using a semiconductorAs/ GaP/InGaP system demonstrates rectifying characteristics with an ideality factor of 2.3 and a current

Woodall, Jerry M.

389

Neuron, Vol. 20, 9951005, May, 1998, Copyright 1998 by Cell Press A Novel Inward Rectifier K Channel  

E-print Network

Neuron, Vol. 20, 995­1005, May, 1998, Copyright ©1998 by Cell Press A Novel Inward Rectifier K depolarized, and between de- We have cloned a novel K -selective, inward rectifier polarizations only small Kir subfamilies (Kir1-ATP­regulated inward rectifier K present in a wide array of tissues, including

Clapham, David E.

390

Rectified Brownian movement in molecular and cell biology  

NASA Astrophysics Data System (ADS)

A unified model is presented for rectified Brownian movement as the mechanism for a variety of putatively chemomechanical energy conversions in molecular and cell biology. The model is established by a detailed analysis of ubiquinone transport in electron transport chains and of allosteric conformation changes in proteins. It is applied to P-type ATPase ion transporters and to a variety of rotary arm enzyme complexes. It provides a basis for the dynamics of actin-myosin cross-bridges in muscle fibers. In this model, metabolic free energy does no work directly, but instead biases boundary conditions for thermal diffusion. All work is done by thermal energy, which is harnessed at the expense of metabolic free energy through the establishment of the asymmetric boundary conditions.

Fox, Ronald F.

1998-02-01

391

Carbon monoxide inhibits inward rectifier potassium channels in cardiomyocytes.  

PubMed

Reperfusion-induced ventricular fibrillation (VF) severely threatens the lives of post-myocardial infarction patients. Carbon monoxide (CO)--produced by haem oxygenase in cardiomyocytes--has been reported to prevent VF through an unknown mechanism of action. Here, we report that CO prolongs action potential duration (APD) by inhibiting a subset of inward-rectifying potassium (Kir) channels. We show that CO blocks Kir2.2 and Kir2.3 but not Kir2.1 channels in both cardiomyocytes and HEK-293 cells transfected with Kir. CO directly inhibits Kir2.3 by interfering with its interaction with the second messenger phosphatidylinositol (4,5)-bisphosphate (PIP2). As the inhibition of Kir2.2 and Kir2.3 by CO prolongs APD in myocytes, cardiac Kir2.2 and Kir2.3 are promising targets for the prevention of reperfusion-induced VF. PMID:25118981

Liang, Shenghui; Wang, Quanyi; Zhang, Weiwei; Zhang, Hailin; Tan, Shengjiang; Ahmed, Asif; Gu, Yuchun

2014-01-01

392

Asymptotics of Best-Packing on Rectifiable Sets  

E-print Network

We investigate the asymptotic behavior, as $N$ grows, of the largest minimal pairwise distance of $N$ points restricted to an arbitrary compact rectifiable set embedded in Euclidean space, and we find the limit distribution of such optimal configurations. For this purpose, we compare best-packing configurations with minimal Riesz $s$-energy configurations and determine the $s$-th root asymptotic behavior (as $s\\to \\infty)$ of the minimal energy constants. We show that the upper and the lower dimension of a set defined through the Riesz energy or best-packing coincides with the upper and lower Minkowski dimension, respectively. For certain sets in ${\\rm {\\bf R}}^d$ of integer Hausdorff dimension, we show that the limiting behavior of the best-packing distance as well as the minimal $s$-energy for large $s$ is different for different subsequences of the cardinalities of the configurations.

S. V. Borodachov; D. P. Hardin; E. B. Saff

2006-05-05

393

Controlled nucleation and growth process for large grained polycrystalline silicon photovoltaics  

E-print Network

Research has been conducted to develop a new means of producing large grained polycrystlline thin films for photovoltaic applications. The process is one of growth of controlled crystalline nuclei in an a-Si film. For this ...

Danforth, Stephen C.

1982-01-01

394

Predictive & Prognostic Controller for Wide Band Gap (Silicon Carbide) Power Conversion (Preprint).  

National Technical Information Service (NTIS)

This report was developed under a SBIR contract. This paper presents an approach to predictive control and prognostication intended to increase the confidence levels for power converters in aerospace applications. One goal of this work is to accelerate th...

G. Davis, L. Casey, B. Jordan, J. Scofield, K. Keller

2006-01-01

395

Molecular characterization of an inwardly rectifying K+ channel from HeLa cells.  

PubMed

Previous patch-clamp studies have shown that the potassium permeability of the plasma membrane in HeLa cells, a cell line derived from an epidermoid carcinoma of the cervix, is controlled by various K+-selective pores including an IRK1 type inwardly rectifying K+ channel. We used the sequence previously reported for the human heart Kir2.1 channel to design a RT-PCR strategy for cloning the IRK1 channel in HeLa cells. A full-length clone of 1.3 kb was obtained that was identical to the human cardiac Kir2.1 inward rectifier. The nature of the cloned channel was also confirmed in a Northern blot analysis where a signal of 5.3 kb corresponding to the molecular weight expected for a Kir2.1 channel transcript was identified not only in HeLa cells, but also in WI-38, ECV304 and bovine aortic endothelial cells. The HeLa IRK1 channel cDNA was subcloned in an expression vector (pMT21) and injected into Xenopus oocytes. Cell-attached and inside-out single channel recordings obtained from injected oocytes provided evidence for a voltage-independent K+-selective channel with current/voltage characteristics typical of a strong inward rectifier. The single channel conductance for inward currents measured in 200 mm K2SO4 conditions was estimated at 40 +/- 1 pS (n = 3), for applied voltages ranging from -100 to -160 mV, in agreement with the unitary conductance for the IRK1 channel identified in HeLa cells. In addition, the single channel conductance for inward currents, Gamma, was found to vary as a function of alphaK, the external K+ ion activity, according to Gamma = Gamma0 [alphaK]delta with Gamma0 = 3.3 pS and delta = 0.5. Single channel recordings from injected oocytes also provided evidence of a voltage-dependent block by external Cs+ and Ba2+. The presence of 500 micron Cs+ caused a voltage-dependent flickering, typical of a fast channel blocking process which resulted in a reduction of the channel open probability at increasingly negative membrane potential values. The fractional electrical distance computed for the Cs+ blocking site was greater than 1 indicating a multiple ion channel occupation. In contrast, external Ba2+ at concentrations ranging from 25 to 100 micron caused a slow channel block, consistent with the binding of a single Ba2+ ion at a site located at half the membrane span. It is concluded on the basis of these observations that HeLa cells expressed a Kir2.1 type inwardly rectifying channel likely to be involved in maintaining and regulating the cell resting potential. PMID:9878074

Klein, H; Garneau, L; Coady, M; Lemay, G; Lapointe, J Y; Sauv, R

1999-01-01

396

ON THE INFLUENCE OF RECOMBINATION CENTERS ON THE ELECTRICAL PERFORMANCE OF SILICON POWER RECTIFIERS  

E-print Network

are more often considered. In this paper, we present a more rigorous approach of the case of amphoteric with an elementary recombination rate Ui and the effective lifetime is 1.2 AMPHOTERIC CENTERS. - Consider now

Paris-Sud XI, Université de

397

DNA Physical Mapping via the Controlled Translocation of Single Molecules through a 5-10nm Silicon Nitride Nanopore  

NASA Astrophysics Data System (ADS)

The ability to map the binding position of sequence-specific markers, including transcription-factors, protein-nucleic acids (PNAs) or deactivated restriction enzymes, along a single DNA molecule in a nanofluidic device would be of key importance for the life-sciences. Such markers could give an indication of the active genes at particular stage in a cell's transcriptional cycle, pinpoint the location of mutations or even provide a DNA barcode that could aid in genomics applications. We have developed a setup consisting of a 5-10 nm nanopore in a 20nm thick silicon nitride film coupled to an optical tweezer setup. The translocation of DNA across the nanopore can be detected via blockades in the electrical current through the pore. By anchoring one end of the translocating DNA to an optically trapped microsphere, we hope to stretch out the molecule in the nanopore and control the translocation speed, enabling us to slowly scan across the genome and detect changes in the baseline current due to the presence of bound markers.

Stein, Derek; Reisner, Walter; Jiang, Zhijun; Hagerty, Nick; Wood, Charles; Chan, Jason

2009-03-01

398

Controlled thickness and dielectric constant titanium-doped SiO2 thin films on silicon by sol gel process  

NASA Astrophysics Data System (ADS)

In this paper, we report the preparation of crack-free relatively thick SiO2-TiO2 thin films on silicon substrates using the sol-gel spin-coating method. The influence of the process parameters on the quality of the film, such as the solution condition, the spin-coating speed, the heat treatment temperature and time, have been studied. We found that the cracking of the film could be avoided by selecting the right sol composition ratios, adding PVA to the sold and properly controlling the heat treatment. Most importantly, we discovered that by polishing the edges of the film after the deposition of each single layer, the number of such layers that deposited without crack formation could be substantially increased. The refractive index profile and thickness of the film have been determined using prism coupling technique and the inverse WKB method. The refractive index was found to depend on the content of TiO2 as well as the heat treatment condition. Using an AFM, the surface morphology of the film was found to be good.

Liu, H. L.; Wang, S. S.; Zhou, Yan; Lam, Yee Loy; Chan, Yuen Chuen; Kam, Chan Hin

1997-08-01

399

Wafer-scale fabrication of silicon nanowire arrays with controllable dimensions  

NASA Astrophysics Data System (ADS)

A novel and facile method was successfully developed to fabricate wafer-scale Si nanowire arrays with well-controlled sizes through the in-situ porous anodic alumina (PAA) template-assisted wet-etching process. The diameter and filling ratio (inter-wire spacing) of the as-prepared Si nanowires are determined by the size and density of pores in the in-situ PAA templates, which can be tailored independently by adjusting the anodization voltages and the immersion time of PAA templates in phosphoric acid. The length of Si nanowires can be more than one hundred micrometers long, which is controlled by adjusting the wet-etching time. Moreover, this method is compatible with complex Si surface topology for creating desirable 3-dimensional hybrid micro/nano-structures. Such Si nanowire arrays exhibit ultralow reflectance and interesting wettability that are of great importance to photovoltaics and thermal management applications.

Wang, Wei; Li, Dan; Tian, Miao; Lee, Yung-Cheng; Yang, Ronggui

2012-09-01

400

[Iris prosthesis in traumatic aniridia as an attempt to control refractory glaucoma induced by silicone oil in the anterior chamber: case report].  

PubMed

The objective of this report is to demonstrate the effectiveness of an iris prosthesis to treat a refractory glaucoma induced by silicone oil in the anterior chamber. This case is about a patient who suffered a trauma caused by firearm shrapnel. A vitreous-retinal surgery was performed to remove intraocular foreign matter and to realign the retina that was detached. Due to the partial traumatic aniridia, silicone oil that was introduced in the vitreous chamber to keep the retina in place migrated to the anterior chamber, resulting in the decrease of endothelium cells and uncontrollable intraocular pressure. We performed transscleral fixation of the iris prosthesis to correct these problems. After a 45-month period of evolution, sight became stable at the 1 meter finger-count distance and intra-ocular pressure at 14 mmHg We may conclude that the triad that consists of lack of: iris diaphragm, aphakia and silicone oil that could not be removed because of inexorable occurrence of detachment of the retina should lead the surgeon to consider transscleral fixation of the iris prosthesis. This procedure might control intraocular pressure and/or preserve corneal transparency, preventing silicone oil from contact with the trabecular net and the corneal endothelium. PMID:16059575

Torres, Rogil Jos de Almeida; Luchini, Andra; Torres, Rogrio Joo de Almeida; Abib, Fernando Csar; Torres, Reginaldo Antnio de Almeida

2005-01-01

401

An RF Energy Harvester System Using UHF Micropower CMOS Rectifier Based on a Diode Connected CMOS Transistor  

PubMed Central

This paper presents a new type diode connected MOS transistor to improve CMOS conventional rectifier's performance in RF energy harvester systems for wireless sensor networks in which the circuits are designed in 0.18??m TSMC CMOS technology. The proposed diode connected MOS transistor uses a new bulk connection which leads to reduction in the threshold voltage and leakage current; therefore, it contributes to increment of the rectifier's output voltage, output current, and efficiency when it is well important in the conventional CMOS rectifiers. The design technique for the rectifiers is explained and a matching network has been proposed to increase the sensitivity of the proposed rectifier. Five-stage rectifier with a matching network is proposed based on the optimization. The simulation results shows 18.2% improvement in the efficiency of the rectifier circuit and increase in sensitivity of RF energy harvester circuit. All circuits are designed in 0.18??m TSMC CMOS technology. PMID:24782680

Shokrani, Mohammad Reza; Hamidon, Mohd Nizar B.; Rokhani, Fakhrul Zaman; Shafie, Suhaidi Bin

2014-01-01

402

An RF energy harvester system using UHF micropower CMOS rectifier based on a diode connected CMOS transistor.  

PubMed

This paper presents a new type diode connected MOS transistor to improve CMOS conventional rectifier's performance in RF energy harvester systems for wireless sensor networks in which the circuits are designed in 0.18? ?m TSMC CMOS technology. The proposed diode connected MOS transistor uses a new bulk connection which leads to reduction in the threshold voltage and leakage current; therefore, it contributes to increment of the rectifier's output voltage, output current, and efficiency when it is well important in the conventional CMOS rectifiers. The design technique for the rectifiers is explained and a matching network has been proposed to increase the sensitivity of the proposed rectifier. Five-stage rectifier with a matching network is proposed based on the optimization. The simulation results shows 18.2% improvement in the efficiency of the rectifier circuit and increase in sensitivity of RF energy harvester circuit. All circuits are designed in 0.18 ?m TSMC CMOS technology. PMID:24782680

Shokrani, Mohammad Reza; Khoddam, Mojtaba; Hamidon, Mohd Nizar B; Kamsani, Noor Ain; Rokhani, Fakhrul Zaman; Shafie, Suhaidi Bin

2014-01-01

403

Commissioning of the control and data acquisition electronics for the CDF Silicon Vertex Detector  

SciTech Connect

The SVX data acquisition system includes three components: a Fastbus Sequencer, an SVX Rabbit Crate Controller and a Digitizer. These modules are integrated into the CDF DAQ system and operate the readout chips. The results of the extensive functional tests of the SVX modules are reported. We discuss the stability of the Sequencers, systematic differences between them and methods of synchronization with the Tevatron beam crossings. The Digitizer ADC calibration procedure run on the microsequencer is described. The microsequencer code used for data taking and SVX chip calibration modes is described. Measurements of the SVX data scan time are discussed.

Tkaczyk, S.M.; Turner, K.J.; Nelson, C.A.; Shaw, T.M.; Wesson, T.R. [Fermi National Accelerator Lab., Batavia, IL (United States); Bailey, M.W.; Kruse, M.C. [Purdue Univ., Lafayette, IN (United States); Castro, A. [Padua Univ. (Italy)

1991-11-01

404

Methanol to olefins: activity and stability of nanosized SAPO-34 molecular sieves and control of selectivity by silicon distribution.  

PubMed

Nano-SAPO-34 molecular sieves synthesized in a microwave environment with 20 nm crystal size showed a longer lifetime than SAPO-34 prepared by the conventional hydrothermal method in the reaction of methanol to olefins. It has been found that silicon distribution strongly affects the lifetime and selectivity. Thus, silicon at the border of the silicon islands gives a higher lifetime and lower C2/C3 ratio. This change in activity and selectivity is better explained in terms of different silicon distribution than by preferential diffusion of ethene through the 8MR pores and agrees with transition-state selectivity. The effects of equilibrium of olefins and deactivation by coke were isolated, showing that after full formation of the hydrocarbon pool, selectivity is independent of deactivation by coke. PMID:23897003

Li, Zhibin; Martnez-Triguero, Joaqun; Concepcin, Patricia; Yu, Jihong; Corma, Avelino

2013-09-21

405

The ratio of germanium to silicon in plant phytoliths: quantification of biological discrimination under controlled experimental conditions  

Microsoft Academic Search

Slight differences in the chemical behavior of germanium (Ge) and silicon (Si) during soil weathering enable Ge\\/Si ratios\\u000a to be used as a tracer of Si pathways. Mineral weathering and biogenic silicon cycling are the primary modifiers of Ge\\/Si\\u000a ratios, but knowledge of the biogenic cycling component is based on relatively few studies. We conducted two sets of greenhouse\\u000a experiments

Steve W. Blecker; Stagg L. King; Louis A. Derry; Oliver A. Chadwick; James A. Ippolito; Eugene F. Kelly

2007-01-01

406

Strained-Silicon on Silicon and Strained-Silicon on Silicon-Germanium on Silicon by Relaxed  

E-print Network

Strained-Silicon on Silicon and Strained-Silicon on Silicon-Germanium on Silicon by Relaxed Buffer of Technology, Cambridge, Massachusetts 02139, USA b AmberWave Systems Corporation, Salem, New Hampshire 03079 platforms: strained-silicon on silicon SSOS and strained-silicon on silicon-germanium on silicon SGOS . SSOS

407

Position-controlled uniform GaAs nanowires on silicon using nanoimprint lithography.  

PubMed

We report on the epitaxial growth of large-area position-controlled self-catalyzed GaAs nanowires (NWs) directly on Si by molecular beam epitaxy (MBE). Nanohole patterns are defined in a SiO2 mask on 2 in. Si wafers using nanoimprint lithography (NIL) for the growth of positioned GaAs NWs. To optimize the yield of vertical NWs the MBE growth parameter space is tuned, including Ga predeposition time, Ga and As fluxes, growth temperature, and annealing treatment prior to NW growth. In addition, a non-negligible radial growth is observed with increasing growth time and is found to be independent of the As species (i.e., As2 or As4) and the growth temperatures studied. Cross-sectional transmission electron microscopy analysis of the GaAs NW/Si substrate heterointerface reveals an epitaxial growth where NW base fills the oxide hole opening and eventually extends over the oxide mask. These findings have important implications for NW-based device designs with axial and radial p-n junctions. Finally, NIL positioned GaAs/AlGaAs core-shell heterostructured NWs are grown on Si to study the optical properties of the NWs. Room-temperature photoluminescence spectroscopy of ensembles of as-grown core-shell NWs reveals uniform and high optical quality, as required for the subsequent device applications. The combination of NIL and MBE thereby demonstrates the successful heterogeneous integration of highly uniform GaAs NWs on Si, important for fabricating high throughput, large-area position-controlled NW arrays for various optoelectronic device applications. PMID:24467394

Munshi, A M; Dheeraj, D L; Fauske, V T; Kim, D C; Huh, J; Reinertsen, J F; Ahtapodov, L; Lee, K D; Heidari, B; van Helvoort, A T J; Fimland, B O; Weman, H

2014-02-12

408

27 CFR 1.21 - Domestic producers, rectifiers, blenders, and warehousemen.  

...basic permit issued under the Act, shall: (a) Engage in the business of distilling distilled spirits, producing wine, rectifying or blending distilled spirits or wine, or bottling, or warehousing and bottling, distilled spirits; or (b)...

2014-04-01

409

27 CFR 1.21 - Domestic producers, rectifiers, blenders, and warehousemen.  

Code of Federal Regulations, 2013 CFR

...basic permit issued under the Act, shall: (a) Engage in the business of distilling distilled spirits, producing wine, rectifying or blending distilled spirits or wine, or bottling, or warehousing and bottling, distilled spirits; or (b)...

2013-04-01

410

Analysis of three-phase rectifiers with constant-voltage loads  

E-print Network

This work presents a quantitative analysis of the operating characteristics of three-phase diode bridge rectifiers with AC-side reactance and constant-voltage loads. We focus on the case where the AC-side currents vary ...

Caliskan, Vahe

411

Switched-capacitor step-down rectifier for low-voltage power conversion  

E-print Network

This paper presents a switched-capacitor rectifier that provides step down voltage conversion from an ac input voltage to a dc output. Coupled with current-drive source, low-loss and high step-down rectification is realized. ...

Li, Wei

412

27 CFR 1.21 - Domestic producers, rectifiers, blenders, and warehousemen.  

Code of Federal Regulations, 2010 CFR

...basic permit issued under the Act, shall: (a) Engage in the business of distilling distilled spirits, producing wine, rectifying or blending distilled spirits or wine, or bottling, or warehousing and bottling, distilled spirits; or (b)...

2010-04-01

413

27 CFR 1.21 - Domestic producers, rectifiers, blenders, and warehousemen.  

Code of Federal Regulations, 2012 CFR

...basic permit issued under the Act, shall: (a) Engage in the business of distilling distilled spirits, producing wine, rectifying or blending distilled spirits or wine, or bottling, or warehousing and bottling, distilled spirits; or (b)...

2012-04-01

414

27 CFR 1.21 - Domestic producers, rectifiers, blenders, and warehousemen.  

Code of Federal Regulations, 2011 CFR

...basic permit issued under the Act, shall: (a) Engage in the business of distilling distilled spirits, producing wine, rectifying or blending distilled spirits or wine, or bottling, or warehousing and bottling, distilled spirits; or (b)...

2011-04-01

415

Theoretical and experimental study of 2.45 GHz rectifying antennas  

E-print Network

This thesis presents a study on 2.45 GHz rectifying antennas (rectennas). The rectenna is a major component in a microwave power transmission system. The main feature is the conversion efficiency from microwave power to direct current (DC) power...

McSpadden, James Oliver

2012-06-07

416

Rectifiability of Sets of Finite Perimeter in a class of Carnot Groups of arbitrary step  

E-print Network

In this Note, we define a class of Carnot groups of arbitrary step (that are called "groups of type $\\star$" throughout the paper), and we prove that the reduced boundary of a set of finite intrinsic perimeter in a group of type $\\star$ is rectifiable in the intrinsic sense (De Giorgi's rectifiability theorem). This result extends previous results proved by Franchi, Serapioni & Serra Cassano in step 2 groups.

Marchi, Marco

2012-01-01

417

Electrostatic tuning of Mg2+ affinity in an inward-rectifier K+ channel  

Microsoft Academic Search

INWARD-RECTIFIER potassium channels conduct K+across the cell membrane more efficiently in the inward than outward direction. This unusual conduction property is directly related to the biological action of these channels1-6. One basis for inward rectification is voltage-dependent blockade by intracellular Mg2+ (refs 1, 7-9): strong inward-rectifier channels are so sensitive to intracellular Mg2+ that no outward K+ current is measurable

Zhe Lu; Roderick MacKinnon

1994-01-01

418

Voltage sag ride-through for adjustable-speed drives with active rectifiers  

Microsoft Academic Search

Adjustable-speed drives (ASDs) trip due to voltage sags, interfering with production and resulting in financial losses. In this paper, a methodology for incorporating voltage sag ride-through in the design of ASDs with active rectifiers is presented. The magnitude of the voltage sag for which ride-through can be provided is determined by the current rating of the active rectifier and load

Annabelle van Zyl; R. Spee; A. Faveluke; S. Bhowmik

1998-01-01

419

A new zero-voltage transition, three-phase PWM rectifier\\/inverter circuit  

Microsoft Academic Search

A switching rectifier\\/inverter technique that combines the conventional three-phase, six-stepped pulse-width modulated (PWM) rectifier\\/inverter with a simple commutation circuit to provide zero-voltage turn-on for the switches and soft turn-off for the diodes is presented. The commutation circuit is active only during a short period of the switching cycle, thus it consumes minimum power and does not impair the normal constant

V. Vlatkovic; D. Borojevic; F. Lee; C. Cuadros; S. Gataric

1993-01-01

420

Optimum System Design of a Three-Phase Rectifier-Inverter Type of Frequency Changer  

Microsoft Academic Search

Steadily decreasing prices and improved performance of semiconductor devices have raised expectations towards the development and large-scale application of motor-mounted static converters. In view of this, the design of a rectifier-inverter type of frequency changer which requires very small reactive components is considered. Accordingly, rectifier and inverter PWM schemes which generate the minimum possible harmonic distortion are first discussed. By

Phoivas D. Ziogas; Young-Goo Kang; Victor R. Stefanovic

1985-01-01

421

AviramRatner rectifying mechanism for DNA base-pair sequencing through graphene nanogaps  

Microsoft Academic Search

We demonstrate that biological molecules such as WatsonCrick DNA base pairs can behave as biological AviramRatner electrical rectifiers because of the spatial separation and weak hydrogen bonding between the nucleobases. We have performed a parallel computational implementation of the ab initio non-equilibrium Greens function (NEGF) theory to determine the electrical response of graphenebase-pairgraphene junctions. The results show an asymmetric (rectifying)

Luis A Agapito; Jacob Gayles; Christian Wolowiec; Nicholas Kioussis

2012-01-01

422

DC Link Active Power Filter for Three-Phase Diode Rectifier  

Microsoft Academic Search

In this paper, a dc link active power filter (APF) for three-phase diode rectifier is proposed. The proposed dc link APF, which is composed of two series-connected bidirectional boost converters, intends to eliminate the input current harmonics. It is paralleled at the dc link of the diode rectifier and is coupled to the ac input with three line-frequency switches. Compared

Xiong Du; Luowei Zhou; Hao Lu; Heng-Ming Tai

2012-01-01

423

Improved three-phase high-quality rectifier with line-commutated switches  

Microsoft Academic Search

The paper presents a three-phase diode rectifier with an add-on simple cell with line-frequency commutated ac switches that is able to greatly improve both power factor and output voltage regulation of rectifiers with passive L-C filters. The boost action introduced by the commutation cell allows for a complete compensation of the voltage drop across the input inductors, so as output

J. A. G. Marafao; J. A. Pomilio; G. Spiazzi

2004-01-01

424

Large area, ultra-high voltage 4H-SiC p-i-n rectifiers  

Microsoft Academic Search

This paper reports the design, fabrication and high temperature characteristics of 1 mm2, 4 mm2 and 9 mm2 4H-SiC p-i-n rectifiers with 6 kV, 5 kV, and 10 kV blocking voltage, respectively. These results were obtained from two lots in an effort to increase the total power levels on such rectifiers. An innovative design utilizing a highly doped p-type epitaxial

Ranbir Singh; Kenneth G. Irvine; D. Craig Capell; James T. Richmond; David Berning; Allen R. Hefner; John W. Palmour

2002-01-01

425

Barrier inhomogeneities and electrical characteristics of Ti\\/4H-SiC Schottky rectifiers  

Microsoft Academic Search

Forward density-voltage (J-V) measurements of titanium\\/4H-SiC Schottky rectifiers are presented in a large temperature range. While some of the devices present a behavior in accordance with the thermionic current theory, others present an excess forward current at low voltage level. This anomaly appears more or less depending on the rectifier and on the temperature. A model based on two parallel

Dominique Defives; Olivier Noblanc; C. Dua; Christian Brylinski; Marc Barthula; V. Aubry-Fortuna; Francoise Meyer

1999-01-01

426

Design and test of a 2.25-MW transformer rectifier assembly  

NASA Technical Reports Server (NTRS)

A new 2.25-MW transformer rectifier assembly was fabricated for DSS-13 at Goldstone, California. The transformer rectifier will provide constant output power of 2.25 MW at any voltage from 31 kV to 125 kV. This will give a new capability of 1 MW of RF power at X-band, provided appropriate microwave tubes are in the power amplifier. A description of the design and test results is presented.

Cormier, R.; Daeges, J.

1989-01-01

427

Charge-controlled fixation of DNA molecules on silicon surface and electro-physical properties of Au-DNA-Si interface  

NASA Astrophysics Data System (ADS)

Light-induced fixation of DNA molecules on silicon surface was done and electro-physical properties of Schottky diodes with DNA on interfaces were investigated. Thymus DNA molecules were deposited on silicon from a water solution. Fixed molecular structures were observed with helium ionic microscopy and atomic force microscopy and then they were covered with thermal sputtered gold film. Obtained structures Au-DNA-(n-Si) were examined with current-voltage and frequency dependent admittance measurements. In darkness immobilizing of molecules leaded to form DNA ropes with thickness up to 10 nm and distances between them about 1 mkm. Fixation under illumination resulted in forming of single DNA mesh with thickness about 1 nm and cell size about 100 nm. Presence of molecular mesh on interface leaded to increasing of charge density controlled by metal Fermi level and improved diode quality. Presence of molecular ropes resulted in increasing of charge density controlled by semiconductor. From the estimation of interface state density values the origin of the states at the interface between DNA and silicon substrate is suggested to be DNA phosphate groups contacting or being close to the substrate surface.

Bazlov, N. V.; Vyvenko, O. F.; Sokolov, P. A.; Kas'yanenko, N. A.; Petrov, Yu V.

2013-02-01

428

Effects of insertion of hole injection layers on pentacene rectifying diodes.  

PubMed

The main issue of the organic rectifier, the key element in radio frequency identification tags, is to improve forward-bias current density of an organic diode in the rectifier, which increases the frequency response of the rectifier. One approach to achieve high current density is inserting a hole injection layer (HIL) between the anode and the active layer to enhance the charge injection efficiency. Here we study the effect of HILs in pentacene rectifying diodes. Three different hole injection layers are applied to the pentacene diode: molybdenum trioxide (MoO3), 1,4,5,8,9,11-hexaazatriphenylene hexacarbonitrile (HAT-CN), and poly(3,4-ethylenedioxythiophene): poly(styrenesulfonate) (PEDOT:PSS). A rectifier consists of the diode with a capacitor. The results show that current density of diodes with HILs is increased by more than three orders of magnitude compared with the diode without a HIL. The diode with MoO3 and that with HAT-CN shows similar forward bias current density, while that of the diode with PEDOT:PSS is slightly lower than those. Finally, the output voltage of the rectifier with a HIL is 4.6 V at 100 MHz when input voltage of 10 V is applied. PMID:24758021

Kang, Chan-Mo; Cho, Hyunduck; Park, Myeongjin; Roh, Jeongkyun; Lee, Changhee

2014-07-01

429

New analysis and design of a RF rectifier for RFID and implantable devices.  

PubMed

New design and optimization of charge pump rectifiers using diode-connected MOS transistors is presented in this paper. An analysis of the output voltage and Power Conversion Efficiency (PCE) is given to guide and evaluate the new design. A novel diode-connected MOS transistor for UHF rectifiers is presented and optimized, and a high efficiency N-stage charge pump rectifier based on this new diode-connected MOS transistor is designed and fabricated in a SMIC 0.18-?m 2P3M CMOS embedded EEPROM process. The new diode achieves 315 mV turn-on voltage and 415 nA reverse saturation leakage current. Compared with the traditional rectifier, the one based on the proposed diode-connected MOS has higher PCE, higher output voltage and smaller ripple coefficient. When the RF input is a 900-MHz sinusoid signal with the power ranging from -15 dBm to -4 dBm, PCEs of the charge pump rectifier with only 3-stage are more than 30%, and the maximum output voltage is 5.5 V, and its ripple coefficients are less than 1%. Therefore, the rectifier is especially suitable to passive UHF RFID tag IC and implantable devices. PMID:22163968

Liu, Dong-Sheng; Li, Feng-Bo; Zou, Xue-Cheng; Liu, Yao; Hui, Xue-Mei; Tao, Xiong-Fei

2011-01-01

430

Innovative Switching Sequences for Sensorless Capacitor Voltage Balancing of Three-Phase NPC Rectifier  

NASA Astrophysics Data System (ADS)

This paper presents a modulation strategy for self-balancing of capacitor voltages of three-phase neutral-point clamped bi-directional rectifier (without feedback controller and sensors). It is identified that regions within a sector are divided into two categories: (a) One small vector among three selected vectors and (b) Two small vectors among three selected vectors. For category (a) positive and negative commutation state of small vector is implemented for equal duty cycle but for category (b) positive and negative commutation state of small vectors is implemented for unequal duty cycle. Based on this observation, an innovative idea is executed to remove these discrepancies. The innovative optimized space vector switching sequences negative and positive commutation state of both the small vectors are implemented for equal duty cycle during each sampling period resulting in self-balancing of DC-bus capacitors with much reduced ripples under steady-state and dynamic load conditions for both rectification and inversion mode of operation. The converter exhibits excellent performance in terms of other critical parameters like unity input power factor, low input current THD, minimum possible switching losses, reduced-rippled and well-regulated DC voltage. The proposed control algorithm is tested through exhaustive simulation of converter using MATLAB Simulink software.

Langer, Nitin; Bhat, Abdul Hamid; Agarwal, Pramod

2014-01-01

431

The fabrication of highly ordered block copolymer micellar arrays: control of the separation distances of silicon oxide dots  

NASA Astrophysics Data System (ADS)

We demonstrate the fabrication of highly ordered silicon oxide dotted arrays prepared from polydimethylsiloxane (PDMS) filled nanoporous block copolymer (BCP) films and the preparation of nanoporous, flexible Teflon or polyimide films. Polystyrene-block-poly(2-vinylpyridine) (PS-b-P2VP) films were annealed in toluene vapor to enhance the lateral order of micellar arrays and were subsequently immersed in alcohol to produce nano-sized pores, which can be used as templates for filling a thin layer of PDMS. When a thin layer of PDMS was spin-coated onto nanoporous BCP films and thermally annealed at a certain temperature, the PDMS was drawn into the pores by capillary action. PDMS filled BCP templates were exposed to oxygen plasma environments in order to fabricate silicon oxide dotted arrays. By addition of PS homopolymer to PS-b-P2VP copolymer, the separation distances of micellar arrays were tuned. As-prepared silicon oxide dotted arrays were used as a hard master for fabricating nanoporous Teflon or polyimide films by spin-coating polymer precursor solutions onto silicon patterns and peeling off. This simple process enables us to fabricate highly ordered nanoporous BCP templates, silicon oxide dots, and flexible nanoporous polymer patterns with feature size of sub-20 nm over 5 cm 5 cm.

Yoo, Hana; Park, Soojin

2010-06-01

432

In situ thickness control during plasma deposition of hydrogenated amorphous silicon films by time-resolved microwave conductivity measurements.  

PubMed

Transient photoconductivity measurements have been performed in situ during plasma-enhanced chemical vapor deposition of amorphous hydrogenated silicon by a contactless method that uses the change of the microwave reflection after laser pulse illumination. Through the use of the interference pattern of the amplitude of the transients of microwave reflection during the layer growth, the actual thickness of the amorphous film can be determined. In the case of crystalline silicon substrates, the change in the light absorption in the substrate modified by the growth of the amorphous layer is measured directly. An example of the optimization of antireflective layers on crystalline silicon substrates is shown. A good agreement is found between the experimental data and calculations of optical reflection and transmission on the multilayer structures. PMID:20963168

Neitzert, H C; Hirsch, W; Kunst, M; Nell, M E

1995-02-01

433

Low temperature, high quality silicon dioxide thin films deposited using tetramethylsilane (TMS) for stress control and coverage applications  

US Patent & Trademark Office Database

Silicon dioxide thin film have been deposited at temperatures from 25.degree. C. to 250.degree. C. by plasma enhanced chemical vapor deposition (PECVD) using tetramethylsilane (TMS) as the silicon containing precursor. At these temperatures, the PETMS oxide films have been found to exhibit adjustable stress and adjustable conformality. Post deposition annealing in forming gas at or below the deposition temperatures has been shown to be very effective in improving the PETMS oxide properties while preserving the low temperature aspect of the PETMS oxides.

2003-03-11

434

BOREAS TE-18, 60-m, Radiometrically Rectified Landsat TM Imagery  

NASA Technical Reports Server (NTRS)

The BOREAS TE-18 team used a radiometric rectification process to produce standardized DN values for a series of Landsat TM images of the BOREAS SSA and NSA in order to compare images that were collected under different atmospheric conditions. The images for each study area were referenced to an image that had very clear atmospheric qualities. The reference image for the SSA was collected on 02-Sep-1994, while the reference image for the NSA was collected on 2 1 Jun-1995. The 23 rectified images cover the period of 07-Jul-1985 to 18-Sep-1994 in the SSA and 22-Jun-1984 to 09-Jun-1994 in the NSA. Each of the reference scenes had coincident atmospheric optical thickness measurements made by RSS-11. The radiometric rectification process is described in more detail by Hall et al. (1991). The original Landsat TM data were received from CCRS for use in the BOREAS project. Due to the nature of the radiometric rectification process and copyright issues, the full-resolution (30-m) images may not be publicly distributed. However, this spatially degraded 60-m resolution version of the images may be openly distributed and is available on the BOREAS CD-ROM series. After the radiometric rectification processing, the original data were degraded to a 60-m pixel size from the original 30-m pixel size by averaging the data over a 2- by 2-pixel window. The data are stored in binary image-format files. The data files are available on a CD-ROM (see document number 20010000884), or from the Oak Ridge National Laboratory (ORNL) Distributed Activity Archive Center (DAAC).

Hall, Forrest G. (Editor); Knapp, David

2000-01-01

435

BOREAS TE-18, 30-m, Radiometrically Rectified Landsat TM Imagery  

NASA Technical Reports Server (NTRS)

The BOREAS TE-18 team used a radiometric rectification process to produce standardized DN values for a series of Landsat TM images of the BOREAS SSA and NSA in order to compare images that were collected under different atmospheric conditions. The images for each study area were referenced to an image that had very clear atmospheric qualities. The reference image for the SSA was collected on 02-Sep-1994, while the reference image for the NSA was collected on 21-Jun-1995. the 23 rectified images cover the period of 07-Jul-1985 to 18 Sep-1994 in the SSA and from 22-Jun-1984 to 09-Jun-1994 in the NSA. Each of the reference scenes had coincident atmospheric optical thickness measurements made by RSS-11. The radiometric rectification process is described in more detail by Hall et al. (199 1). The original Landsat TM data were received from CCRS for use in the BOREAS project. The data are stored in binary image-format files. Due to the nature of the radiometric rectification process and copyright issues, these full-resolution images may not be publicly distributed. However, a spatially degraded 60-m resolution version of the images is available on the BOREAS CD-ROM series. See Sections 15 and 16 for information about how to possibly acquire the full resolution data. Information about the full-resolution images is provided in an inventory listing on the CD-ROMs. The data files are available on a CD-ROM (see document number 20010000884), or from the Oak Ridge National Laboratory (ORNL) Distributed Activity Archive Center (DAAC).

Hall, Forrest G. (Editor); Knapp, David

2000-01-01

436

An inwardly rectifying K+ channel is required for patterning  

PubMed Central

Mutations that disrupt function of the human inwardly rectifying potassium channel KIR2.1 are associated with the craniofacial and digital defects of Andersen-Tawil Syndrome, but the contribution of Kir channels to development is undefined. Deletion of mouse Kir2.1 also causes cleft palate and digital defects. These defects are strikingly similar to phenotypes that result from disrupted TGF?/BMP signaling. We use Drosophila melanogaster to show that a Kir2.1 homolog, Irk2, affects development by disrupting BMP signaling. Phenotypes of irk2 deficient lines, a mutant irk2 allele, irk2 siRNA and expression of a dominant-negative Irk2 subunit (Irk2DN) all demonstrate that Irk2 function is necessary for development of the adult wing. Compromised Irk2 function causes wing-patterning defects similar to those found when signaling through a Drosophila BMP homolog, Decapentaplegic (Dpp), is disrupted. To determine whether Irk2 plays a role in the Dpp pathway, we generated flies in which both Irk2 and Dpp functions are reduced. Irk2DN phenotypes are enhanced by decreased Dpp signaling. In wild-type flies, Dpp signaling can be detected in stripes along the anterior/posterior boundary of the larval imaginal wing disc. Reducing function of Irk2 with siRNA, an irk2 deletion, or expression of Irk2DN reduces the Dpp signal in the wing disc. As Irk channels contribute to Dpp signaling in flies, a similar role for Kir2.1 in BMP signaling may explain the morphological defects of Andersen-Tawil Syndrome and the Kir2.1 knockout mouse. PMID:22949619

Dahal, Giri Raj; Rawson, Joel; Gassaway, Brandon; Kwok, Benjamin; Tong, Ying; Ptacek, Louis J.; Bates, Emily

2012-01-01

437

Semiconductor-to-metal Transition Control in Novel Vanadium Dioxide/Silicon and Vanadium Dioxide/Sapphire Epitaxial Thin Film Heterostructures for Device Applications  

NASA Astrophysics Data System (ADS)

Novel functionalities of Vanadium dioxide (VO2), such as, several orders of magnitude transition in resistivity and IR transmittance, provide an exciting opportunity for the development of next generation memory, sensor, and field-effect based devices. A critical issue in the development of practical devices based on metal oxides is the integration of high quality epitaxial oxide thin films with the existing silicon technology which is based on silicon (100) substrates. However, silicon is not suitable for epitaxial growth of oxides owing to its tendency to readily form an amorphous oxide layer or silicide at the film-substrate interface. The oxide films deposited directly on silicon exhibit poor crystallinity and are not suitable for device applications. To overcome this challenge, appropriate substrate templates must be developed for the growth of oxide thin films on silicon substrates. The primary objective of this dissertation was to develop an integration methodology of VO2 with Si (100) substrates so they could be used in "smart" sensor type of devices along with other multifunctional devices on the same silicon chip. This was achieved by using yttria-stabilized zirconia (YSZ) template layer deposited in situ. It will be shown that if the deposition conditions are controlled properly, YSZ can be grown epitaxially on silicon substrates even if the native oxide is not etched completely prior to deposition. I have used this approach to integrate VO2 thin films with Si (100) substrates using pulsed laser deposition (PLD) technique. The deposition methodology of integrating VO2 thin films on silicon using various other template layers will also be discussed. The detailed x-ray diffraction, transmission electron microscopy (TEM), electrical characterization results for the deposited films will be presented. In the framework on domain matching epitaxy, epitaxial growth of VO2 (tetragonal crystal structure at growth temperature) on both tetragonal and cubic YSZ has been explained. Our detailed phi-scan X-ray diffraction measurements corroborate our understanding of the epitaxial growth and in-plane atomic arrangements at the interface. It was observed that the transition characteristics (sharpness, over which electrical and optical property changes are completed, amplitude, transition temperature, and hysteresis) are a strong function of microstructure, strain, and stoichiometry. We have shown that by choosing the right template layer, strain in the VO2 thin films can be fully relaxed and near-bulk VO2 transition temperatures can be achieved. We have demonstrated this by using NiO as a buffer layer on Al2O3 (0001) substrate. We have also used swift heavy ion irradiation to induce controlled modifications in the semiconductor-to-metal transition characteristics of VO2 single-crystal thin films with varying ion fluences. At very high energies of ions (200 MeV), the electronic stopping (2009 eV/A) dominates over nuclear stopping (16 eV/A). Under these extreme electronic excitation conditions caused by electronic stopping and the passage of swift heavy ions through the entire thickness of the film, we expect creation of certain unique type of defects and disordered regions. Detailed characterization using X-ray diffraction, Raman spectroscopy, infra-red transmission spectroscopy, x-ray photoelectron spectroscopy (XPS), and electrical measurements were performed to investigate the characteristics and role of these defects on structural, optical, and electrical properties of VO2 thin films. XPS andelectrical resistivity measurements suggest that the ion-irradiation induces localized defect states which appear to correlate well with the creation of disordered regions in the VO2 thin films. The high energy heavy ion-irradiation changes the transition characteristics drastically from a first-order to a second-order transition (electronic -- Mott type). The low temperature conductance data for these ion-irradiated films fits well with the quasi-amorphous model for resistivity of VO2 where ion-irradiation is believed to

Gupta, Alok

438

Advances in the understanding of low molecular weight silicon formation and implications for control by AMC filters  

Microsoft Academic Search

Trimethylsilanol (TMS) is a low molecular weight \\/ low boiling point silicon-containing, airborne contaminant that has received increased interest over the past few years as an important cause for contamination of optical surfaces in lithography equipment. TMS is not captured well by carbon-based filters, and hexamethyldisiloxane (HMDSO), even though captured well, can be converted to TMS when using acidic filter

Jrgen M. Lobert; Philip W. Cate; David J. Ruede; Joseph R. Wildgoose; Charles M. Miller; John C. Gaudreau

2010-01-01

439

Inward rectifier K+-channel kinetics from analysis of the complex conductance of Aplysia neuronal membrane.  

PubMed Central

Conduction in inward rectifier, K+-channels in Aplysia neuron and Ba++ blockade of these channels were studied by rapid measurement of the membrane complex admittance in the frequency range 0.05 to 200 Hz during voltage clamps to membrane potentials in the range -90 to -40 mV. Complex ionic conductances of K+ and Cl- rectifiers were extracted from complex admittances of other membrane conduction processes and capacitance by vector subtraction of the membrane complex admittance during suppressed inward K+ current (near zero-mean current and in zero [K+]0) from complex admittances determined at other [K+]0 and membrane potentials. The contribution of the K+ rectifier to the admittance is distinguishable in the frequency domain above 1 Hz from the contribution of the Cl- rectifier, which is only apparent at frequencies less than 0.1 Hz. The voltage dependence (-90 to -40 mV) of the chord conductance (0.2 to 0.05 microS) and the relaxation time (4-8 ms) of K+ rectifier channels at [K+]0 = 40 mM were determined by curve fits of admittance data by a membrane admittance model based on the linearized Hodgkin-Huxley equations. The conductance of inward rectifier, K+ channels at a membrane potential of -80 mV had a square-root dependence on external K+ concentration, and the relaxation time increased from 2 to 7.5 ms for [K+]0 = 20 and 100 mM, respectively. The complex conductance of the inward K+ rectifier, affected by Ba++, was obtained by complex vector subtraction of the membrane admittance during blockage of inward rectifier, K+ channels (at -35 mV and [Ba++]0 = 5 mM) from admittances determined at -80 mV and at other Ba++ concentrations. The relaxation time of the blockade process decreased with increases in Ba++ concentration. An open-closed channel state model produces the inductive-like kinetic behavior in the complex conductance of inward rectifier, K+ channels and the addition of a blocked channel state accounts for the capacitive-like kinetic behavior of the Ba++ blockade process. PMID:2455551

Hayashi, H; Fishman, H M

1988-01-01

440

Silicon membrane nanofilters from sacrificial oxide removal  

Microsoft Academic Search

Silicon micropore filter designs using a sacrificial oxide removal technique are described. These filters utilize surface and bulk micromachining for precise control of pore sizes in the tens of nanometers range. The semipermeable membrane of the sacrificial layer filters (SLFs) is typically composed of sandwiched p+ polysilicon\\/oxide\\/p+ silicon layers where the sacrificial oxide between the two silicon layers determines the

Wen-Hwa Chu; Ruby Chin; Tony Huen; Mauro Ferrari

1999-01-01

441

Reversible Cycling of Silicon and Silicon Alloys  

NASA Astrophysics Data System (ADS)

Lithium ion batteries typically use a graphite negative electrode. Silicon can store more lithium than any other element and has long been considered as an attractive replacement for graphite. The theoretical lithium storage capacity of silicon is nearly ten times higher than graphite volumetrically and three times higher gravimetrically. The equilibrium Si-Li binary system is well known. Completely new phase behaviors are observed at room temperature. This includes the formation of a new phase, Li15Si4, which is the highest lithium containing phase at room temperature [1]. The formation of Li15Si4 is accompanied by a 280 percent volume expansion of silicon. During de-alloying this phase contracts, forming amorphous silicon. The volume expansion of alloys can cause intra-particle fracture and inter-particle disconnection; leading to loss of cycle life. To overcome issues with volume expansion requires a detailed knowledge of Li-Si phase behavior, careful design of the composition and nanostructure of the alloy and the microstructure of the negative electrode [2]. In this presentation the phase behavior of the Li-Si system will be described. Using this knowledge alone, strategies can be developed so that silicon can be reversibly cycled in a battery hundreds of times. Further increases in energy density and efficiency can be gained by alloying silicon with other elements, while controlling microstructure [2]. Coupled with negative electrode design strategies, practical negative electrodes for lithium ion cells can be developed based on bulk materials, with significant energy density improvement over conventional electrodes. [4pt] [1] M.N. Obrovac and L.J. Krause, J. Electrochem. Soc., 154 (2007) A103. [0pt] [2] M.N. Obrovac, Leif Christensen, Dinh Ba Le, and J.R. Dahn, J. Electrochem. Soc., 154 (2007) A849

Obrovac, Mark

2012-02-01

442

Simple evaporation controller for thin-film deposition from a resistively heated boat  

NASA Technical Reports Server (NTRS)

A simple, inexpensive circuit is described for switching the current through a resistively heated evaporation boat during thin-film deposition. The circuit uses a silicon-controlled rectifier (SCR) to switch the 0-15-A current in the primary of a 2-kV A step-down transformer that supplies the 0-200-A current to an evaporation boat. The circuit is controlled by a 0-10 V-dc signal similar to that furnished by an Inficon XTC deposition-rate controller. This circuit may be assembled from a handful of parts for a cost of about $400, nearly one-tenth the cost of similar commercial units. Minimum construction is required, since the circuit is built around an off-the-shelf, self-contained SCR unit.

Scofield, John H.; Bajuk, Lou; Mohler, William

1990-01-01

443

Dead-Zone Digital Controller for Improved Dynamic Response of  

E-print Network

-to-medium power, high-frequency applications including dc-dc converters, and single-phase universal-input power complexity or cost. Figure 1 shows a block diagram of a digitally controlled PFC rectifier. Switching the rectified input voltage waveform vg(t) according to: )( )( )( tkv R tv ti g e g g == (1) C + - load AC line

Prodiæ, Aleksandar

444

Controlled morphology and optical properties of n-type porous silicon: effect of magnetic field and electrode-assisted LEF  

PubMed Central

Fabrication of photoluminescent n-type porous silicon (nPS), using electrode-assisted lateral electric field accompanied with a perpendicular magnetic field, is reported. The results have been compared with the porous structures fabricated by means of conventional anodization and electrode-assisted lateral electric field without magnetic field. The lateral electric field (LEF) applied across the silicon substrate leads to the formation of structural gradient in terms of density, dimension, and depth of the etched pores. Apart from the pore shape tunability, the simultaneous application of LEF and magnetic field (MF) contributes to a reduction of the dimension of the pores and promotes relatively more defined pore tips as well as a decreased side-branching in the pore walls of the macroporous structure. Additionally, when using magnetic field-assisted etching, within a certain range of LEF, an enhancement of the photoluminescence (PL) response was obtained. PMID:25313298

2014-01-01

445

A Voltage Controlled Oscillator for a Phase-Locked Loop Frequency Synthesizer in a Silicon-on-Sapphire Process  

E-print Network

.5: Typical single-sideband phase-noise with null null/null null corner frequency highlighted ...........................................................................................43 Figure 3.6: Differentially cross-coupled oscillator core... layer that is used for creating high-Q passive components such as inductors and metal-insulator-metal (MIM) capacitors. The sapphire substrate?s high resistivity has several distinct advantages when compared to a bulk silicon substrate...

Garrison, Sean Michael

2009-05-22

446

CMOS-Based High-Density Silicon Microprobe Arrays for Electronic Depth Control in Intracortical Neural Recording  

Microsoft Academic Search

This paper reports on a novel high-density CMOS-based silicon microprobe array for intracortical recording applications. In contrast to existing systems, CMOS multiplexing units are integrated directly on the slender, needle-like probe shafts. Single-shaft probes and four-shaft combs have been realized with 188 and 752 electrodes, respectively, with a pitch of 40 ?m arranged in two columns along 4-mm-long probe shafts.

Karsten Seidl; Stanislav Herwik; Tom Torfs; Herc P. Neves; Oliver Paul; Patrick Ruther

2011-01-01

447

Isolated two-stage passive PFC rectifier for the Radioisotope Stirling Generator  

NASA Astrophysics Data System (ADS)

This paper describes an isolated, passive power factor correction rectifier devised for low-voltage, large-inductance, single-phase alternator, like the one used in the Radioisotope Stirling Generator. The power converter splits into two independent stages, the front-end rectifier corrects the power factor by adding a series capacitor in the AC line. Further, the rectifier, thanks to the alternator inductance, behaves as a constant-current source that powers a current-fed, zero voltage and zero current switching push-pull stage. This approach takes advantage of all parasitic elements to increase power density while keeping simple and reliable. Full description and analysis is given as well as the design procedure, simulation and experimental results.

Garrigos, A.; Blanes, J. M.; Carrasco, J. A.; Maset, E.; Ejea, J. B.; Montalban, G.; Sanchis-Kilders, E.; Ferreres, A.

448

Rectifying properties of oligo(phenylene ethynylene) heterometallic molecular junctions: molecular length and side group effects.  

PubMed

The rectifying properties of ?,?-dithiol terminated oligo(phenylene ethynylene) molecules sandwiched between heterometallic electrodes, including the molecular length and side group effects, are theoretically investigated using the fully self-consistent nonequilibrium Green's function method combined with density functional theory. The results show nonlinear variation with changes in molecule length: when the molecule becomes longer, the current decreases at first and then increases while the rectification shifts in the opposite direction. This stems from the change in molecular eigenstates and the coupling between the molecule and electrodes caused by different molecular lengths. The rectifying behavior of heterometallic molecular junctions can be attributed to the asymmetric molecule-electrode contacts, which lead to asymmetric electronic tunneling spectra, molecular eigenvalues, molecular orbitals, and potential drop at reversed equivalent bias voltages. Our results provide a fundamental understanding of the rectification of heterometallic molecular junction, and a prediction of rectifiers with different rectification properties from those in the experiment, using electrodes with reduced sizes. PMID:25220880

Fu, Xiao-Xiao; Zhang, Rui-Qin; Zhang, Guang-Ping; Li, Zong-Liang

2014-01-01

449

Rectifying Properties of Oligo(Phenylene Ethynylene) Heterometallic Molecular Junctions: Molecular Length and Side Group Effects  

PubMed Central

The rectifying properties of ?,?-dithiol terminated oligo(phenylene ethynylene) molecules sandwiched between heterometallic electrodes, including the molecular length and side group effects, are theoretically investigated using the fully self-consistent nonequilibrium Green's function method combined with density functional theory. The results show nonlinear variation with changes in molecule length: when the molecule becomes longer, the current decreases at first and then increases while the rectification shifts in the opposite direction. This stems from the change in molecular eigenstates and the coupling between the molecule and electrodes caused by different molecular lengths. The rectifying behavior of heterometallic molecular junctions can be attributed to the asymmetric molecule-electrode contacts, which lead to asymmetric electronic tunneling spectra, molecular eigenvalues, molecular orbitals, and potential drop at reversed equivalent bias voltages. Our results provide a fundamental understanding of the rectification of heterometallic molecular junction, and a prediction of rectifiers with different rectification properties from those in the experiment, using electrodes with reduced sizes. PMID:25220880

Fu, Xiao-Xiao; Zhang, Rui-Qin; Zhang, Guang-Ping; Li, Zong-Liang

2014-01-01

450

Small scale ethanol production demonstration: comparison of packed versus plate rectifying column  

SciTech Connect

The Johnson Environmental and Energy Center with assistance from the Madison County Farm Bureau Association received a grant in 1980 from the US Department of Energy to design, fabricate, and evaluate a small scale continuous ethanol plant. In 1981, the Center received a second DOE grant to compare the economics of replacing the plate rectifying column in the initial unit with a packed rectifying column. The results of the study indicate that the distillation unit with the packed rectifying column is capable of producing 14 gallons per hour of 170 proof ethanol. The energy ratio for distillation was a positive 2:1. Cost of the packed column was considerably less than the plate column. 1 reference, 19 figures, 9 tables.

Adcock, II, L E; Eley, M H; Schroer, B J

1982-07-01

451

An outwardly rectifying anion channel in human leukaemic K562 cells.  

PubMed

In this study, an outwardly rectifying anion channel was characterized in the cell line K562 obtained from a chronic human leukaemia. Ion channel activity was recorded in the cell-detached (inside-out) configuration with standard patch-clamp technology. In most of the K562 cells studied, the channel exhibited low spontaneous activity, an outwardly rectifying current/voltage relationship and single-channel conductances of 19 pS and 40 pS for inwards and outwards currents respectively. The channel had a low permeability for gluconate with a relative permeability P(gluconate)/ P(Cl) of 0.14 and was blocked by glibenclamide (50 micro M) or diphenylamine-2-carboxylate (DPC, 1 mM) added to the cytoplasmic side of the patch. These results are characteristic of the outwardly rectifying Cl channel (ORCC) found in other types of cells. PMID:12355183

Assef, Yanina A; Kotsias, Basilio A

2002-09-01

452

Rectifying Properties of Oligo(Phenylene Ethynylene) Heterometallic Molecular Junctions: Molecular Length and Side Group Effects  

NASA Astrophysics Data System (ADS)

The rectifying properties of ?,?-dithiol terminated oligo(phenylene ethynylene) molecules sandwiched between heterometallic electrodes, including the molecular length and side group effects, are theoretically investigated using the fully self-consistent nonequilibrium Green's function method combined with density functional theory. The results show nonlinear variation with changes in molecule length: when the molecule becomes longer, the current decreases at first and then increases while the rectification shifts in the opposite direction. This stems from the change in molecular eigenstates and the coupling between the molecule and electrodes caused by different molecular lengths. The rectifying behavior of heterometallic molecular junctions can be attributed to the asymmetric molecule-electrode contacts, which lead to asymmetric electronic tunneling spectra, molecular eigenvalues, molecular orbitals, and potential drop at reversed equivalent bias voltages. Our results provide a fundamental understanding of the rectification of heterometallic molecular junction, and a prediction of rectifiers with different rectification properties from those in the experiment, using electrodes with reduced sizes.

Fu, Xiao-Xiao; Zhang, Rui-Qin; Zhang, Guang-Ping; Li, Zong-Liang

2014-09-01

453

A new approach to combatting iodine deficiency in developing countries: the controlled release of iodine in water by a silicone elastomer.  

PubMed Central

OBJECTIVES. Four hundred million people or more may be exposed to iodine deficiency worldwide, in developing countries in particular. Because of the practical problems with existing methods for the large-scale prevention of iodine deficiency, the authors developed a new approach to collective prophylaxis. METHODS. This approach relies on the controlled diffusion of iodine into water from a silicone elastomer. Silicone matrices installed in a bore well released iodine at a rate sufficient to permit the daily per capita intake of at least 100 micrograms of iodine, the amount recommended by the World Health Organization. The matrices were tested over 1 year in a village in Mali, West Africa, an area in which goiter was highly endemic. The effects on the well water and population were compared with those of a placebo system in a control village. RESULTS. An increase in urinary iodine levels was observed in the treated population, and after 12 months the incidence of goiter had fallen from 53.2% to 29.2%. CONCLUSIONS. This new concept, adaptable to all sources of water supply, may contribute to the eradication of iodine deficiency. PMID:8460731

Fisch, A; Pichard, E; Prazuck, T; Sebbag, R; Torres, G; Gernez, G; Gentilini, M

1993-01-01

454

IPM Motor Drive Method Using a New Inverter Having the Operation of High Power Factor Single-phase Diode Rectifier without Electrolytic Capacitor  

NASA Astrophysics Data System (ADS)

This paper proposes a new inverter drive system for an interior permanent magnet (IPM) synchronous motor and an inverter control strategy to obtain the unity power factor operation of the single-phase diode rectifier. The motor drive system for home appliances requires improving the input power factor without a reactor, an electrolytic capacitor and a switching device. This paper can achieve to improve the input power factor without a reactor, a current control-switching converter and an electrolytic capacitor. The proposed system consists of only single-phase diode rectifier, small film capacitor (10uF/kW) across the dc-bus, three-phase inverter and IPM motor. Source side energy provides directly to the motor without smoothing the dc-bus voltage. There are many ripple voltages across the dc-bus. A principle of unity-power-factor operation is that the inverter makes the waveform of input current sinusoidal. The unity power factor operation is achieved by dither effect. For IPM motor, the inverter control scheme in this paper is based on direct torque control (DTC). The proposed system is constructed by the input current controller based on DTC. The additional current controller improves its input current waveform. This paper describes that the proposed method achieves the power factor 98.8% by experimental tests.

Haga, Hitoshi; Takahashi, Isao; Ohishi, Kiyoshi

455

Advances in research on G protein-coupled inward rectifier K(+) channel gene.  

PubMed

G protein-coupled inward rectifier K(+) channel 4(GIRK4) is a G protein-coupled inward rectifier potassium channel family member. Encoded by the KCNJ5, it is widely distributed in the mammalian heart, brain, and other tissues and organs. Recent studies have demonstrated that the abnormal expression of GIRK4 gene is associated with atrial fibrillation, and meanwhile may be closely related to obesity, metabolic syndrome, and many other clinical conditions. Further research on the role the GIRK4 gene in the pathophysiology of these clinical conditions will definitely facilitate their clinical diagnosis and treatment. PMID:22954132

Kang, Yong-an; Hu, Yan-rong; Li, Nan-fang

2012-08-01

456

Recovery Act: High-Efficiency, Wideband Three-Phase Rectifiers and Adaptive Rectifier Management for Telecomm Central Office and Large Data Center Applications  

SciTech Connect

Lineage Power and Verizon teamed up to address a DOE funding opportunity focused on improving the power conversion chain in telecommunications facilities and data centers. The project had three significant elements: the design and development of high efficiency and high power three-phase rectifiers by Lineage Power, design and development of software to optimize overall plant energy efficiency by Lineage Power, and a field trial in active Verizon telecommunications facilities where energy consumption was measured before and after efficiency upgrades.

Mark A. Johnson

2012-06-29

457

Modeling and control of a 50KW electric vehicle fast charger  

Microsoft Academic Search

Modeling and control of a 50KW vehicle battery fast charger prototype, developed at Gamatronic Electronic Industries LTD, is presented in the paper. The charger topology may be referred as a two-stage controlled rectifier. The input stage consists of a three phase full bridge rectifier combined with an active power filter (three single stage power filters are actually employed). The input

Alon Kuperman; U. Levy; J. Goren; A. Zafranski; A. Savernin; I. Peled

2010-01-01

458

MicroRNA-26 governs profibrillatory inward-rectifier potassium current changes in atrial fibrillation  

PubMed Central

Atrial fibrillation (AF) is a highly prevalent arrhythmia with pronounced morbidity and mortality. Inward-rectifier K+ current (IK1) is believed to be an important regulator of reentrant-spiral dynamics and a major component of AF-related electrical remodeling. MicroRNA-26 (miR-26) is predicted to target the gene encoding KIR2.1, KCNJ2. We found that miR-26 was downregulated in atrial samples from AF animals and patients and this downregulation was accompanied by upregulation of IK1/KIR2.1 protein. miR-26 overexpression suppressed expression of KCNJ2/KIR2.1. In contrast, miR-26 knockdown, inhibition, or binding-site mutation enhanced KCNJ2/KIR2.1 expression, establishing KCNJ2 as a miR-26 target. Knockdown of endogenous miR-26 promoted AF in mice, whereas adenovirus-mediated expression of miR-26 reduced AF vulnerability. Kcnj2-specific miR-masks eliminated miR-26mediated reductions in Kcnj2, abolishing miR-26s protective effects, while coinjection of a Kcnj2-specific miR-mimic prevented miR-26 knockdown-associated AF in mice. Nuclear factor of activated T cells (NFAT), a known actor in AF-associated remodeling, was found to negatively regulate miR-26 transcription. Our results demonstrate that miR-26 controls the expression of KCNJ2 and suggest that this downregulation may promote AF. PMID:23543060

Luo, Xiaobin; Pan, Zhenwei; Shan, Hongli; Xiao, Jiening; Sun, Xuelin; Wang, Ning; Lin, Huixian; Xiao, Ling; Maguy, Ange; Qi, Xiao-Yan; Li, Yue; Gao, Xu; Dong, Deli; Zhang, Yong; Bai, Yunlong; Ai, Jing; Sun, Lihua; Lu, Hang; Luo, Xiao-Yan; Wang, Zhiguo; Lu, Yanjie; Yang, Baofeng; Nattel, Stanley

2013-01-01

459

ATP-mediated vasodilatation occurs via activation of inwardly rectifying potassium channels in humans  

PubMed Central

Circulating ATP possesses unique vasomotor properties in humans and has been hypothesized to play a role in vascular control under a variety of physiological conditions. However, the primary downstream signalling mechanisms underlying ATP-mediated vasodilatation remain unclear. The purpose of the present experiment was to determine whether ATP-mediated vasodilatation is independent of nitric oxide (NO) and prostaglandin (PG) synthesis and occurs primarily via the activation of Na+/K+-ATPase and inwardly rectifying potassium (KIR) channels in humans. In all protocols, young healthy adults were studied and forearm vascular conductance (FVC) was calculated from forearm blood flow (measured via venous occlusion plethysmography) and intra-arterial blood pressure to quantify local vasodilatation. Vasodilator responses (%?FVC) during intra-arterial ATP infusions were unchanged following combined inhibition of NO and PGs (n= 8; P > 0.05) whereas the responses to KCl were greater (P < 0.05). Combined infusion of ouabain (to inhibit Na+/K+-ATPase) and barium chloride (BaCl2; to inhibit KIR channels) abolished KCl-mediated vasodilatation (n= 6; %?FVC = 134 13 vs. 4 5%; P < 0.05), demonstrating effective blockade of direct vascular hyperpolarization. The vasodilator responses to three different doses of ATP were inhibited on average 56 5% (n= 16) following combined ouabain plus BaCl2 infusion. In follow-up studies, BaCl2 alone inhibited the vasodilator responses to ATP on average 51 3% (n= 6), which was not different than that observed for combined ouabain plus BaCl2 administration. Our novel results indicate that the primary mechanism of ATP-mediated vasodilatation is vascular hyperpolarization via activation of KIR channels. These observations translate in vitro findings to humans in vivo and may help explain the unique vasomotor properties of intravascular ATP in the human circulation. PMID:22777673

Crecelius, Anne R; Kirby, Brett S; Luckasen, Gary J; Larson, Dennis G; Dinenno, Frank A

2012-01-01

460

Improving point registration in dental cephalograms by two-stage rectified point translation transform  

NASA Astrophysics Data System (ADS)

Cephalometric analysis requires to detect landmarks on cephalograms. Current registration techniques, such as that use scale-invariant feature descriptor (SIFT), perform poorly on cephalograms. We proposed to improve the registration technique for detecting the landmarks on cephalograms. The results were compared with the landmark identified by dental professionals. Twenty digital cephalograms were collected from a dental clinic. Twenty orthodontic landmarks were identified by dental professionals on each image; one of them was used as a template image. We automatically locate the landmarks using a two stages approach, the global registration of the interest points between two images and a local registration of the landmarks. In the first stage, SIFT was employed to establish point-to-point matching pairs. The matched points on the input image were treated as a set of translation transforms from the original template image. The consistence of the translation was controlled by applying a rectification factor defined in this study. In the second stage, we localized the search within the suspected regions around the landmarks derived by the translations in the first stage. Local registrations were rectified and fine-tuned until the translations close to the identified landmarks were obtained. Our method could detect all the landmarks with error distances less than the 2mm standard set forth by previous researcher. By improving the consistence of the translations, the performance of registration between two images was greatly improved. This method can be used as an initial step to locate the regions around the landmarks for improving detection in the future work.

Tam, W. K.; Lee, H. J.

2012-02-01

461

Diffusion-controlled growth of hydrogen pores in aluminum-silicon castings: In situ observation and modeling  

SciTech Connect

In situ observations were made of the nucleation and growth kinetics of hydrogen porosity during the directional solidification of aluminium-7 wt% silicon (Al7Si) with TiB{sub 2} grain refiner added, using an X-ray temperature gradient stage (XTGS). The effect of altering the solidification velocity on the growth rate and morphology of the porosity formed was characterized by tracking individual pores with digital analysis of the micro-focal video images. It was found that increasing the solidification velocity caused the pore radius to decrease and pore density to increase. Insight gained from the experimental results was used to develop a computational model of the evolution of hydrogen pores during solidification of aluminum-silicon cast alloys. The model solves for the diffusion-limited growth of the pores in spherical coordinates, using a deterministic solution of the grain nucleation and growth as a sub-model to calculate the parameters that depend upon the fraction solid. Sensitivity analysis was carried out to assess the effects of equiaxed grain density, pore density, initial hydrogen content and cooling rate. The model agrees with the experimental results within the resolution limits of the XTGS experiments performed.

Atwood, R.C.; Sridhar, S.; Zhang, W.; Lee, P.D.

2000-01-24

462

Silicone-Acyclovir Controlled Release Devices Suppress Primary Herpes Simplex Virus-2 and Varicella Zoster Virus Infections In Vitro  

PubMed Central

Following initial infection, herpesviruses retreat into a permanent latent state with periodic reactivation resulting in an enhanced likelihood of transmission and clinical disease. The nucleoside analogue acyclovir reduces clinical symptoms of the three human alpha herpesviruses, HSV-1, HSV-2, and VZV. Long-term administration of acyclovir (ACV) can reduce the frequency and severity of reactivation, but its low bioavailability and short half-life require a daily drug regimen. Our lab is working to develop a subcutaneous delivery system to provide long-lasting, sustained release of ACV. Previously, we demonstrated that an implantable silicone (MED-4050) device, impregnated with ACV protected against HSV-1 both in vitro and in vivo. Here, we extend our in vitro observations to include protection against both HSV-2 and VZV. We also demonstrate protection against HSV-2 in vitro using MED-4750, a silicone polymer designed for long-term use in humans. When release of ACV from MED-4750 is quantitated on a daily basis, an initial burst of 5 days is observed, followed by a long period of slow release with near-zero-order kinetics, with an average daily release of 1.3923 0.5908??g ACV over days 2060. Development of a slow-release implant has the potential to significantly impact the treatment of human alpha herpesvirus infections. PMID:23983683

Berkower, Carol L.; Johnson, Nicole M.; Longdo, Stephen B.; McGusty-Robinson, Shenika O.; Semenkow, Samantha L.; Margulies, Barry J.

2013-01-01

463

High-Efficiency CMOS Rectifier for Fully Integrated mW Wireless Power Transfer  

E-print Network

C are remotely powered by means of two coupled inductors and a power amplifier operating at a fixed carrier coupled wireless power transfer receivers. The rectifier uses feedback from the output to lower, lifetime and packaging issues. Within this domain, near-field inductive coupling is one of the most

Gulak, P. Glenn

464

An analysis of three-phase rectifiers with constant voltage loads  

Microsoft Academic Search

In this paper, a numerical analysis of three-phase voltage loaded rectifiers is presented. The simulation is performed on the equation system level, for normalized circuit model. Possible combinations of diode states are analyzed, and it is shown that out of 26 = 64 combinations only 13 might occur. For all of the combinations, circuit equations and boundary inequalities are derived.

Predrag Pejovic; Johann W. Kolar

2010-01-01

465

Effect of High-Speed Rectifier Excitation Systems on Generator Stability Limits  

Microsoft Academic Search

A device to provide a signal proportional to changes in generator speed has been developed by Ontario Hydro. Field tests have been performed to demonstrate that use of this signal with a high-speed rectifier excitation system results in dynamic stability limits which approximate those which can be obtained with a zero reactance generator. Transient stability limits are greater than those

Paul Dandeno; Alex Karas; Kenneth McClymont; Wilfred Watson

1968-01-01

466

Analysis and Simplified Representations of a Rectifier-Inverter Induction Motor Drive  

Microsoft Academic Search

Simplified representations of a rectifier-inverter induction motor drive system are established and verified by comparing the results obtained from a computer study using these representations to those obtained using a detailed simulation of the system. It is shown that when all harmonic components are neglected the static drive system may be conveniently represented in the synchronously rotating reference frame. The

Paul Krause; Thomas Lipo

1969-01-01

467

A simple and efficient synchronous rectifier for forward DC-DC converters  

Microsoft Academic Search

A simple and efficient MOSFET synchronous rectification circuit suitable for forward DC-DC power converters is proposed. The main feature of this circuit is the addition of a capacitor in parallel with the drain source of the MOSFET used as a rectifying device. This capacitor extends the conduction period of the MOSFET used as a freewheeling device. As a result, a

N. Murakami; H. Namiki; K. Sakakibara; T. Yachi

1993-01-01

468

Rectified images of selected geologic maps in the Northern Rockies Area, Idaho, Montana, Washington, and Wyoming  

USGS Publications Warehouse

Selected geologic maps covering parts of the Northern Rocky Mountains and adjacent areas were converted to raster images and georeferenced (rectified) for use in a geographic information system (GIS). These rectified images were created for the purpose of visually comparing published geologic maps with other geospatial information. However, they cannot be queried or used for spatial analysis thus limiting their use in a GIS. The 42 georeferenced images included in this report range in scale from 1:250,000 to 1:100,000.Tagged Image Format (TIFF) images of the maps were generated by scanning an original paper map or converting previously published Portable Document Format (PDF) images or Encapsulated Post-Script (EPS) files. To reduce file size and minimize image overlap, the TIFF images were cropped, and then rectified using ArcMap? 8 and converted to MrSID? images. Information in the explanation and cross sections can be viewed in un-rectified images of the original publications that are included with this report. In addition, the text in the map unit description along with the unit name, map label, and a citation are organized in a searchable PDF file.

Larsen, Jeremy C.; Assmus, Kenneth C.; Causey, J. Douglas; Zientek, Michael L.

2004-01-01

469

Ohmic conductance through the inwardly rectifying K channel and blocking by internal Mg2+  

Microsoft Academic Search

The inwardly rectifying K channel provides the resting K conductance in a variety of cells1-4. This channel acts as a valve or diode, permitting entry of K+ under hyperpolarization, but not its exit under depolarization. This behaviour, termed inward rectification, permits long depolarizing responses which are of physiological significance for the pumping function of the heart and for fertilization of

Hiroko Matsuda; Akihiro Saigusa; Hiroshi Irisawa

1987-01-01

470

A switching power supply of 99% power factor by the dither rectifier  

Microsoft Academic Search

The authors present a current waveform improvement method, based on the dither effect normally used in the linearization of nonlinear functions. The proposed circuit utilizes this principle to linearize the dead-zone characteristic which is present in the input of capacitor input rectifiers. The principal characteristics of this method are its simple composition and, more importantly, that it avoids the need

I. Takahashi; R. Y. Igarashi

1991-01-01

471

New Method for Reducing Harmonics Involved in Input and Output of Rectifier with Interphase Transformer  

Microsoft Academic Search

A new effective method for reducing harmonics involved in input ac line currents or output dc voltage of the thyristor rectifier apparatus with an interphase transformer is proposed. This method is based on the sophisticated utilization of several thyristors inserted in parallel between several taps equipped symmetrically for the midpoint of the interphase transformer and the terminal of the dc

Shota Miyairi; Shoji Iida; Kiyoshi Nakata; Shigeo Masukawa

1986-01-01

472

ON RECTIFIED LINEAR UNITS FOR SPEECH PROCESSING M.D. Zeiler1  

E-print Network

hundred hours of speech data. Index Terms-- Rectified Linear units, Deep Learning, Neural Networks-wise un- supervised learning algorithm, called Restricted Boltzmann Machine (RBM) [2], as a way to provide nets [5, 6]. Inspired by recent work on deep learning for vision ap- plications [7, 8, 9], we propose

Hinton, Geoffrey E.

473

Effects of Serotonin on Caudal Raphe Neurons: Activation of an Inwardly Rectifying Potassium Conductance  

Microsoft Academic Search

Effects of serotonin on caudal raphe neurons: activation of an properties and that was depolarized by 5-HT. inwardly rectifying potassium conductance. J. Neurophysiol.77: 1349 - 1361, 1997. We used whole cell current- and voltage- clamp recording in neonatal rat brain stem slices to characterize firing properties and effects of serotonin ( 5-HT ) on neurons IN T R O DU

DOUGLAS A. BAYLISS; YU-WEN LI; EDMUND M. TALLEY

474

Image force effect on forward characteristic of a rectifier metal-semiconductor contact  

Microsoft Academic Search

The image force effect is appreciated, especially, for the reverse regime of the rectifier metal-semiconductor contact, causing a weak dependence of the saturation current on the applied voltage. Applying this concept to the forward bias, at high values of currents, the ideality factor has an important increase. Combining this effect with the effect of the series resistance, which is important

D. Dobrescu; A. Rusu; F. Udrea; L. Dobrescu

2001-01-01

475

Phase-Rectified Signal Averaging to Evaluate ANS Development in Premature Infants  

E-print Network

-Rectified Signal Averaging, Heart Rate Variability, Autonomic Nervous System, Quasi-Periodicities, Non-Stationary Signals. Abstract: Aim: Heart Rate Variability (HRV) is determined by the autonomic nervous system (ANS, the study of heart rate variability (HRV) has gained growing importance. As a matter of fact, the cardiac

476

Autoconnected-electronic-transformer-based multipulse rectifiers for utility interface of power electronic systems  

Microsoft Academic Search

In this paper, an autoconnected electronic transformer (ACET) for 12- and 24-pulse rectifier systems is proposed. Considerable reduction in size and weight is achieved by operating the transformer core at a higher frequency. The rating of the autotransformer is a fraction of the output power. Utility line currents are multipulse in nature with the cancellation of several lower order harmonic

Moonshik Kang; B. O. Woo; P. Enjeti; Ira J. Pitel

1999-01-01

477

Projecting Rectified Images in an Augmented Environment Stanislaw Borkowski, Olivier Riff and James L. Crowley  

E-print Network

Projecting Rectified Images in an Augmented Environment Stanislaw Borkowski, Olivier Riff and James L. Crowley email: {Stan.Borkowski, Olivier.Riff, James.Crowley}@inrialpes.fr Projet PRIMA, Lab in the environment is restricted to a cone resulting from the mirror-projector configuration. In this paper we

Crowley, James L.

478

Rectifying the Inconsistent Administration Procedures of the Cognistat Constructional Ability Subtest  

Microsoft Academic Search

The Cognistat is one of the most widely used psychometric instruments to quickly assess higher cerebral functioning. However, when administered according to the manual, the constructional ability subtest yields results that are confounded by other cognitive processes, as well as blemished by intra-test inconsistencies. Such issues decrease the validity, and ultimately the utility, of this screening device. Suggestions for rectifying

H. Edward Fouty; Sara B. Brzezinski

2009-01-01

479

A new structure of LLC with primary current driven synchronous rectifier  

Microsoft Academic Search

LLC resonant converter has become an excellent candidate for front-end dc-dc converter because of its high efficiency and capability of optimizing the converter for normal operation condition over a wide input voltage and load range. However, lack of suitable driving scheme for the synchronous rectifier (SR) limits the efficiency improvement of LLC in the wide input voltage condition. Although corporations

Bo Yuan; Ming Xu; Xu Yang; Donghao Li

2009-01-01

480

An improved high-power factor and low-cost three-phase rectifier  

Microsoft Academic Search

A new method to improve the power factor of three-phase rectifiers is introduced in this paper. The main features of the proposed circuit are low cost, small size, high efficiency, and simplicity. The power factor improvement is achieved with three bi-directional active switches rated at a small fraction of the total processed power, and gated at the line frequency. The

Ewaldo L. M. Mehl; Ivo Barbi

1997-01-01

481

Effectiveness of different designs of 12- and 24-pulse rectifier transformers  

Microsoft Academic Search

Investigation of effectiveness of different designs of rectifier transformers of tram traction substations has covered issues such as transformer weight, rated power and efficiency and traction line voltage quality. Mathematical models have been created and time and frequency domain analysis has been run as well as power, voltage and current calculations for steady-state conditions. It is pointed out that transformer

A. Sikora; B. Kulesz

2008-01-01

482

PHASE-RECTIFIED SIGNAL AVERAGING FOR THE QUANTIFICATION OF THE INFLUENCE OF PRENATAL ANXIETY  

E-print Network

PHASE-RECTIFIED SIGNAL AVERAGING FOR THE QUANTIFICATION OF THE INFLUENCE OF PRENATAL ANXIETY rate variabil- ity, Prenatal anxiety, Autonomic nervous system Abstract: The autonomic nervous system. In this way, the effect of stress and anxiety during pregnancy on the ANS of the baby is analyzed. First

483

Detection of epileptic seizures from single lead ECG by means of phase rectified signal averaging*  

E-print Network

Detection of epileptic seizures from single lead ECG by means of phase rectified signal averaging-- Epileptic seizures have a clear effect on the regu- latory mechanisms of the autonomic nervous system to occur around the onset of the seizure. This paper studies the ECG signals recorded from patients

484

The Journal of Neuroscience, August 1993, 13(8): 3333-3345 Inward-rectifying Potassium Channels in Retinal Glial (Miiller) Cells  

E-print Network

The Journal of Neuroscience, August 1993, 13(8): 3333-3345 Inward-rectifying Potassium Channels. In single- channel, cell-attached patch-clamp experiments, inward- rectifying K+ channels were, in almost that the principal ion channel in all Miiller cell regions is an inward- rectifying K+ channel. Channel density

Newman, Eric A.

485

622 IEEE JOURNAL OF SOLID-STATE CIRCUITS, VOL. 49, NO. 3, MARCH 2014 Co-Design of a CMOS Rectifier and Small Loop  

E-print Network

622 IEEE JOURNAL OF SOLID-STATE CIRCUITS, VOL. 49, NO. 3, MARCH 2014 Co-Design of a CMOS Rectifier-design and integration of a CMOS rectifier and small loop antenna is described. In order to improve the sensitivity, the antenna-rectifier interface is analyzed as it plays a crucial role in the co-design optimization

Serdijn, Wouter A.

486

PWM Regenerative Rectifiers: State of the Art J. Rodriguez, Senior Member, IEEE, J. Dixon, J. Espinoza, Member, IEEE, and P. Lezana.  

E-print Network

1 PWM Regenerative Rectifiers: State of the Art J. Rodr´iguez, Senior Member, IEEE, J. Dixon, J harmonics injected by power converters, what is achieved with Pulse Width Modulated (PWM) rectifiers presents the state of the art in the field of regenerative rectifiers with reduced input harmonics

Catholic University of Chile (Universidad Católica de Chile)

487

Surface Plasmon and Geometry Enhanced Asymmetric Rectifying Tunneling Diodes Kwangsik Choi, Geunmin Ryu, Filiz Yesilkoy, Athanasios Chryssis, Mario Dagenais, Neil Goldsman and Martin  

E-print Network

Surface Plasmon and Geometry Enhanced Asymmetric Rectifying Tunneling Diodes Kwangsik Choi, Geunmin for efficiently detecting and rectifying such waves. An RF energy scavenger can be conceived using a metal frequencies with different rectified current levels. To confirm that this result is not from "parasitic

Dagenais, Mario

488

Layer-by-Layer Assembly of Rectifying Junctions in and on Metal Nanowires Nina I. Kovtyukhova,*,, Benjamin R. Martin, Jeremiah K. N. Mbindyo, Peter A. Smith,|  

E-print Network

Layer-by-Layer Assembly of Rectifying Junctions in and on Metal Nanowires Nina I. Kovtyukhova rectifying junctions. Concentric structures with similar properties were prepared by first coating-V characteristics of nanowires prepared by either technique show current rectifying behavior. The electronic

489

J. Phys. III Yonce 7 (1997) 1523-1535 JULY 1997, PAGE 1523 Metal-n-InP Rectifying Properties Enhaucement with Zn Based  

E-print Network

J. Phys. III £Yonce 7 (1997) 1523-1535 JULY 1997, PAGE 1523 Metal-n-InP Rectifying Properties functions Abstract. Rectifying contacts on n-InP using Zn based metallizations followed by moderate and rectifying diodes using simple metal semiconductor contact is rather obvious. Another interest in obtaining

Paris-Sud XI, Université de

490

442 15. Basics of the Differential Geometry of Curves We now consider how the rectifying plane varies. This will uncover the  

E-print Network

442 15. Basics of the Differential Geometry of Curves We now consider how the rectifying plane the tangent line for points t + close enough to t. 15.7 Torsion (3D Curves) Recall that the rectifying plane is the important fact. Since the equation of the rectifying plane is N · MP = 0 or N · P = N · M, by familiar

Gallier, Jean

491

IEEE TRANSACTIONS ON CIRCUITS AND SYSTEMS--I: REGULAR PAPERS, VOL. 54, NO. 6, JUNE 2007 1177 Low-Power CMOS Rectifier Design for  

E-print Network

-Power CMOS Rectifier Design for RFID Applications Soumyajit Mandal, Student Member, IEEE, and Rahul-field RF power extraction systems consisting of antennas, impedance matching networks and rectifiers. Funda planar antennas, coupled resonator impedance matching networks and low-power rectifiers in standard CMOS

Sarpeshkar, Rahul

492

Controlled release delivery of penciclovir via a silicone (MED-4750) polymer: kinetics of drug delivery and efficacy in preventing primary feline herpesvirus infection in culture  

PubMed Central

Background Herpesviruses are ubiquitous pathogens that infect and cause recurrent disease in multiple animal species. Feline herpesvirus-1 (FHV-1), a member of the alphaherpesvirus family, causes respiratory illness and conjunctivitis, and approximately 80% of domestic cats are latently infected. Oral administration of famciclovir or topical application of cidofovir has been shown in masked, placebo-controlled prospective trials to reduce clinical signs and viral shedding in experimentally inoculated cats. However, to the authors knowledge, other drugs have not been similarly assessed or were not safe or effective. Likewise, to our knowledge, no drugs have been assessed in a placebo-controlled manner in cats with recrudescent herpetic disease. Controlled-release devices would permit long-term administration of these drugs and enhance compliance. Methods We therefore engineered implantable cylindrical devices made from silicone (MED-4750) impregnated with penciclovir, for long-term, steady-state delivery of this drug. Results Our data show that these devices release penciclovir with a burst of drug delivery until the tenth day of release, then at an average rate of 5.063??1.704?g per day through the next 50days with near zero-order kinetics (in comparison to MED-4750-acyclovir devices, which show the same burst kinetics and average 2.236??0.625?g/day thereafter). Furthermore, these devices suppress primary infection of FHV-1 in a cell culture system. Conclusions The clinical deployment of these silicone-penciclovir devices may allow long-term treatment of FHV-1 infection with a single intervention that could last the life of the host cat. PMID:24558980

2014-01-01

493

PEGylation of porous silicon using click chemistry.  

PubMed

Porous silicon has received considerable interest in recent years in a range of biomedical applications, with its performance determined by surface chemistry. In this work, we investigate the PEGylation of porous silicon wafers using click chemistry. The porous silicon wafer surface chemistry was monitored at each stage of the reaction via photoacoustic Fourier transform infrared spectroscopy and X-ray photoelectron spectroscopy, whereas sessile drop contact angle and model protein adsorption measurements were used to characterize the final PEGylated surface. This work highlights the simplicity of click-chemistry-based functionalization in tailoring the porous silicon surface chemistry and controlling protein-porous silicon interactions. PMID:18590303

Britcher, Leanne; Barnes, Timothy J; Griesser, Hans J; Prestidge, Clive A

2008-08-01

494

TOPICAL REVIEW: Black silicon method X: a review on high speed and selective plasma etching of silicon with profile control: an in-depth comparison between Bosch and cryostat DRIE processes as a roadmap to next generation equipment  

NASA Astrophysics Data System (ADS)

An intensive study has been performed to understand and tune deep reactive ion etch (DRIE) processes for optimum results with respect to the silicon etch rate, etch profile and mask etch selectivity (in order of priority) using state-of-the-art dual power source DRIE equipment. The research compares pulsed-mode DRIE processes (e.g. Bosch technique) and mixed-mode DRIE processes (e.g. cryostat technique). In both techniques, an inhibitor is added to fluorine-based plasma to achieve directional etching, which is formed out of an oxide-forming (O2) or a fluorocarbon (FC) gas (C4F8 or CHF3). The inhibitor can be introduced together with the etch gas, which is named a mixed-mode DRIE process, or the inhibitor can be added in a time-multiplexed manner, which will be termed a pulsed-mode DRIE process. Next, the most convenient mode of operation found in this study is highlighted including some remarks to ensure proper etching (i.e. step synchronization in pulsed-mode operation and heat control of the wafer). First of all, for the fabrication of directional profiles, pulsed-mode DRIE is far easier to handle, is more robust with respect to the pattern layout and has the potential of achieving much higher mask etch selectivity, whereas in a mixed-mode the etch rate is higher and sidewall scalloping is prohibited. It is found that both pulsed-mode CHF3 and C4F8 are perfectly suited to perform high speed directional etching, although they have the drawback of leaving the FC residue at the sidewalls of etched structures. They show an identical result when the flow of CHF3 is roughly 30 times the flow of C4F8, and the amount of gas needed for a comparable result decreases rapidly while lowering the temperature from room down to cryogenic (and increasing the etch rate). Moreover, lowering the temperature lowers the mask erosion rate substantially (and so the mask selectivity improves). The pulsed-mode O2 is FC-free but shows only tolerable anisotropic results at -120 C. The downside of needing liquid nitrogen to perform cryogenic etching can be improved by using a new approach in which both the pulsed and mixed modes are combined into the so-called puffed mode. Alternatively, the use of tetra-ethyl-ortho-silicate (TEOS) as a silicon oxide precursor is proposed to enable sufficient inhibiting strength and improved profile control up to room temperature. Pulsed-mode processing, the second important aspect, is commonly performed in a cycle using two separate steps: etch and deposition. Sometimes, a three-step cycle is adopted using a separate step to clean the bottom of etching features. This study highlights an issue, known by the authors but not discussed before in the literature: the need for proper synchronization between gas and bias pulses to explore the benefit of three steps. The transport of gas from the mass flow controller towards the wafer takes time, whereas the application of bias to the wafer is relatively instantaneous. This delay causes a problem with respect to synchronization when decreasing the step time towards a value close to the gas residence time. It is proposed to upgrade the software with a delay time module for the bias pulses to be in pace with the gas pulses. If properly designed, the delay module makes it possible to switch on the bias exactly during the arrival of the gas for the bottom removal step and so it will minimize the ionic impact because now etch and deposition steps can be performed virtually without bias. This will increase the mask etch selectivity and lower the heat impact significantly. Moreover, the extra bottom removal step can be performed at (also synchronized!) low pressure and therefore opens a window for improved aspect ratios. The temperature control of the wafer, a third aspect of this study, at a higher etch rate and longer etch time, needs critical attention, because it drastically limits the DRIE performance. It is stressed that the exothermic reaction (high silicon loading) and ionic impact (due to metallic masks and/or exposed silicon) are the main sources of heat that might r

Jansen, H V; de Boer, M J; Unnikrishnan, S; Louwerse, M C; Elwenspoek, M C

2009-03-01

495

Direct observation of dangling bond motion in disordered silicon N. H. Nickel  

E-print Network

Direct observation of dangling bond motion in disordered silicon N. H. Nickel Hahn-Meitner-Institut and hydrogen-passivated polycrystalline silicon. This observation invalidates the identification largely control the electronic properties of disor- dered silicons--amorphous, polycrystalline

Schiff, Eric A.

496

Nanometer-scale thickness control of amorphous silicon using isotropic wet-etching and low loss wire waveguide fabrication with the etched material  

NASA Astrophysics Data System (ADS)

Wet-etching with an organic alkaline solution was monitored in situ in semi-real time by optical reflection spectroscopy to achieve high resolution thickness control of hydrogenated amorphous silicon (a-Si:H) film for use in wire waveguides. Isotropic etching resulting from the intrinsic isotropic structure of a-Si:H led to uniform etching with a surface roughness of <1 nm. A moderate etching rate enabled accurate endpoint detection with a resolution of ?1 nm at room temperature. A wire waveguide made of the etched a-Si:H film had a low propagation loss of 1.2 dB/cm, which was almost equivalent to that of an unetched one.

Furuya, K.; Nakanishi, K.; Takei, R.; Omoda, E.; Suzuki, M.; Okano, M.; Kamei, T.; Mori, M.; Sakakibara, Y.

2012-06-01

497

Highly controllable and stable quantized conductance and resistive switching mechanism in single-crystal TiO2 resistive memory on silicon.  

PubMed

TiO2 is being widely explored as an active resistive switching (RS) material for resistive random access memory. We report a detailed analysis of the RS characteristics of single-crystal anatase-TiO2 thin films epitaxially grown on silicon by atomic layer deposition. We demonstrate that although the valence change mechanism is responsible for the observed RS, single-crystal anatase-TiO2 thin films show electrical characteristics that are very different from the usual switching behaviors observed for polycrystalline or amorphous TiO2 and instead very similar to those found in electrochemical metallization memory. In addition, we demonstrate highly stable and reproducible quantized conductance that is well controlled by application of a compliance current and that suggests the localized formation of conducting Magnli-like nanophases. The quantized conductance observed results in multiple well-defined resistance states suitable for implementation of multilevel memory cells. PMID:25072099

Hu, Chengqing; McDaniel, Martin D; Posadas, Agham; Demkov, Alexander A; Ekerdt, John G; Yu, Edward T

2014-08-13

498

Interaction of molten silicon with silicon aluminum oxynitrides  

Microsoft Academic Search

Silicon aluminum oxynitride solid solutions (sialons) based on ..beta..-SiN and SiNO behave differently in contact with molten silicon. The SiNO-based sialons convert to almost pure SiN, apparently through a two-step decomposition and solution-precipitation reaction, whereas, the ..beta..-SiN sialons are preferentially attacked at the grain boundaries. The composition of the