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Sample records for silicon controlled rectifiers

  1. ANALISA SISTEM KENDALI PUTARAN MOTOR DC MENGGUNAKAN SILICON CONTROLLED RECTIFIERS

    Directory of Open Access Journals (Sweden)

    M. Khairudin, Efendi, N Purwantiningsih,

    2016-01-01

    Full Text Available ABSTRAK Paper ini bertujuan untuk menganalisa rangkaian sistem kendali putaran motor menggunakan Silicon Controlled Rectifier (SCR atau Thyristor. Eksperimen sistem kendali putaran motor ini menggunakan dua rangkaian yang berbeda. Rangkaian pertama menggunakan dua sumber, yaitu sumber tegangan DC 12 v terhubung dengan motor universal secara seri dengan resistor dan SCR, sedangkan sumber tegangan DC variabel 0 sampai 1.5 v dihubung paralel dengan kapasitor dan resistor. Rangkaian kedua menggunakan satu sumber tegangan AC 5 v yang dihubungkan dengan saklar dan motor. Pada rangkaian kedua ini motor dihubungkan dengan potensio, SCR, dioda serta kapasitor yang dipasang paralel dengan sumber tegangan AC. Hasil eksperimen menunjukkan dalam rangkaian menggunakan sumber tegangan DC, motor DC akan berputar saat saklar S1 tertutup. Kondisi motor akan berputar lebih cepat ketika sumber tegangan variabel diatur lebih besar dari 0 v sehingga arus gate Ig lebih bear dari 400 mA. Adapun Eksperimen dengan sumber tegangan AC, motor akan berputar dengan menambahkan dioda D3 dan pengaturan kecepatan melalui potensio meter Rv sampai posisi maksimum. Kata kunci: analisa, motor DC, SCR, sistem kendali ABSTRACT The objective of this study is to analyse the circuit of DC motor control system using Silicon Controlled Rectifier (SCR or Thyristor. In this experiment the circuit of control system for the motor using two different circuits. The first circuit using two sources, the 12 v DC voltage is connected to universal motor and series with a resistor and SCR, while the DC variable voltage source of 0 to 1.5 v connected in parallel to the capacitor and resistor. The second circuit uses a single source of 5 V AC voltage connected to the switch and the motor. In the second circuit, the motor is connected to the potentio meter, SCR, diode and capacitor in parallel with the AC voltage source. The experimental results showed the circuit using a DC voltage source impacted the

  2. Understanding of self-terminating pulse generation using silicon controlled rectifier and RC load

    Energy Technology Data Exchange (ETDEWEB)

    Chang, Chris, E-mail: chrischang81@gmail.com; Karunasiri, Gamani, E-mail: karunasiri@nps.edu [Department of Physics, Naval Postgraduate School, Monterey, CA 93943 (United States); Alves, Fabio, E-mail: falves@alionscience.com [Alion Science and Technology at NPS, Monterey, CA 93943 (United States)

    2016-01-15

    Recently a silicon controlled rectifier (SCR)-based circuit that generates self-terminating voltage pulses was employed for the detection of light and ionizing radiation in pulse mode. The circuit consisted of a SCR connected in series with a RC load and DC bias. In this paper, we report the investigation of the physics underlying the pulsing mechanism of the SCR-based. It was found that during the switching of SCR, the voltage across the capacitor increased beyond that of the DC bias, thus generating a reverse current in the circuit, which helped to turn the SCR off. The pulsing was found to be sustainable only for a specific range of RC values depending on the SCR’s intrinsic turn-on/off times. The findings of this work will help to design optimum SCR based circuits for pulse mode detection of light and ionizing radiation without external amplification circuitry.

  3. Silicon-controlled rectifier failure investigation report, April 11 and May 7, 1986, Type A occurrence

    International Nuclear Information System (INIS)

    1986-01-01

    As a result of the April 11, 1986 failure and subsequent property damage of the silicon-controlled rectifier (SCR) device used to provide dc power to the motor driven construction and salt handling (CandSH) hoist at the Waste Isolation Pilot Plant (WIPP), the Project Manager, WIPP Project Office, appointed an Accident Investigation Board on April 14, 1986. The Board was tasked to investigate, to determine the cause or causes of the SCR failure, and to make appropriate recommendations to prevent a recurrence. Subsequently, the scope of the investigation was expanded on April 22, 1986, to include a series of failures that occurred after the initial failure. This occurrence came after the SCR had been released by the Board, repaired, modified, and returned to use. The investigation included a review of the engineering, procurement, operations, and maintenance programs of the Management and Operating Contractor (MOC), along with a detailed investigation of the hardware involved in the failure. Analytical techniques included use of the Management Oversight Risk Tree (MORT) and Events and Causal Factors Sequence Charting. 15 figs

  4. Phase controlled rectifier study

    International Nuclear Information System (INIS)

    Bronner, G.; Murray, J.G.

    1976-03-01

    This report introduces the results of an engineering study incorporating a computer program to determine the transient and steady-state voltage and current wave shapes for a 12-pulse rectifier system. Generally, rectifier engineering studies are completed by making simplified assumptions and neglecting many circuit parameters. The studies incorporate the 3-phase AC parameters including nonlinear source or generator, 3-winding transformer impedances, and shunt and series capacitors. It includes firing angle control, and DC filter circuits with inductive loads

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

    Science.gov (United States)

    Gourash, F.

    1984-01-01

    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.

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

    Science.gov (United States)

    Gourash, F.

    1984-02-01

    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.

  7. A high voltage pulse generator based on silicon-controlled rectifier for field-reversed configuration experiment.

    Science.gov (United States)

    Lin, Munan; Liu, Ming; Zhu, Guanghui; Wang, Yanpeng; Shi, Peiyun; Sun, Xuan

    2017-08-01

    A high voltage pulse generator based on a silicon-controlled rectifier has been designed and implemented for a field reversed configuration experiment. A critical damping circuit is used in the generator to produce the desired pulse waveform. Depending on the load, the rise time of the output trigger signal can be less than 1 μs, and the peak amplitudes of trigger voltage and current are up to 8 kV and 85 A in a single output. The output voltage can be easily adjusted by changing the voltage on a capacitor of the generator. In addition, the generator integrates an electrically floating heater circuit so it is capable of triggering either pseudosparks (TDI-type hydrogen thyratron) or ignitrons. Details of the circuits and their implementation are described in the paper. The trigger generator has successfully controlled the discharging sequence of the pulsed power supply for a field reversed configuration experiment.

  8. Thermally and magnetically controlled superconducting rectifiers

    International Nuclear Information System (INIS)

    Mulder, G.B.J.; TenKate, H.H.J.; Krooshoop, H.J.G.; Van de Klundert, L.J.M.

    1989-01-01

    The switches of a superconducting rectifier can be controlled either magnetically or thermally. The main purpose of this paper is to point out the differences between both methods of switching and discuss the consequences for the operation of the rectifier. The discussion is illustrated by the experimental results of a rectifier which was tested with magnetically as well as thermally controlled switches. It has an input current of 30 A, an output current of more than 1 kA and an operating frequency of a few Hertz. A superconducting magnet connected to this rectifier can be energized at a rate exceeding 1 MJ/hour and an efficiency of about 97%

  9. Chapter 13 - Active Rectifiers and Their Control

    DEFF Research Database (Denmark)

    Davari, Pooya; Zare, Firuz; Abdelhakim, Ahmed

    2018-01-01

    This chapter investigates the control design of active rectifiers and their applications in power electronics-based power system. The harmonic emission and measures are firstly addressed as a basis of evaluating the active rectifier's effectiveness. Furthermore, the importance of new coming...... standards is highlighted. Application-oriented design of active rectifiers as a main reason behind evolvement of different topologies is discussed. Then, the main principle in designing different control schemes in single-phase and three-phase rectifiers is investigated, analyzed, and experimentally...... verified. The influence of nonideal operating conditions with possible solutions is addressed. Finally, future prospective of active rectifiers as a one of the key enabler of carbon-free power system is summarized....

  10. Rectifiers

    CERN Document Server

    Visintini, R

    2006-01-01

    In particle accelerators, rectifiers are used to convert the AC voltage into DC or low-frequency AC to supply loads like magnets or klystrons. Some loads require high currents, others high voltages, and others both high current and high voltage. This presentation deals with the particular class of line commutated rectifiers (the switching techniques are treated elsewhere). The basic principles of rectification are presented. The effects of real world parameters are then taken into consideration. Some aspects related to the filtering of the harmonics both on the DC side and on the AC side are presented. Some protection issues associated with the use of thyristors and diodes are also treated. An example of power converter design, referring to a currently operating magnet power supply, is included. An extended bibliography (including some internet links) ends this presentation.

  11. Time-division-multiplex control scheme for voltage multiplier rectifiers

    Directory of Open Access Journals (Sweden)

    Bin-Han Liu

    2017-03-01

    Full Text Available A voltage multiplier rectifier with a novel time-division-multiplexing (TDM control scheme for high step-up converters is proposed in this study. In the proposed TDM control scheme, two full-wave voltage doubler rectifiers can be combined to realise a voltage quadrupler rectifier. The proposed voltage quadrupler rectifier can reduce transformer turn ratio and transformer size for high step-up converters and also reduce voltage stress for the output capacitors and rectifier diodes. An N-times voltage rectifier can be straightforwardly produced by extending the concepts from the proposed TDM control scheme. A phase-shift full-bridge (PSFB converter is adopted in the primary side of the proposed voltage quadrupler rectifier to construct a PSFB quadrupler converter. Experimental results for the PSFB quadrupler converter demonstrate the performance of the proposed TDM control scheme for voltage quadrupler rectifiers. An 8-times voltage rectifier is simulated to determine the validity of extending the proposed TDM control scheme to realise an N-times voltage rectifier. Experimental and simulation results show that the proposed TDM control scheme has great potential to be used in high step-up converters.

  12. An Inductorless Self-Controlled Rectifier for Piezoelectric Energy Harvesting.

    Science.gov (United States)

    Lu, Shaohua; Boussaid, Farid

    2015-11-19

    This paper presents a high-efficiency inductorless self-controlled rectifier for piezoelectric energy harvesting. High efficiency is achieved by discharging the piezoelectric device (PD) capacitance each time the current produced by the PD changes polarity. This is achieved automatically without the use of delay lines, thereby making the proposed circuit compatible with any type of PD. In addition, the proposed rectifier alleviates the need for an inductor, making it suitable for on-chip integration. Reported experimental results show that the proposed rectifier can harvest up to 3.9 times more energy than a full wave bridge rectifier.

  13. An Inductorless Self-Controlled Rectifier for Piezoelectric Energy Harvesting

    Directory of Open Access Journals (Sweden)

    Shaohua Lu

    2015-11-01

    Full Text Available This paper presents a high-efficiency inductorless self-controlled rectifier for piezoelectric energy harvesting. High efficiency is achieved by discharging the piezoelectric device (PD capacitance each time the current produced by the PD changes polarity. This is achieved automatically without the use of delay lines, thereby making the proposed circuit compatible with any type of PD. In addition, the proposed rectifier alleviates the need for an inductor, making it suitable for on-chip integration. Reported experimental results show that the proposed rectifier can harvest up to 3.9 times more energy than a full wave bridge rectifier.

  14. Comparison of thyristor rectifier characteristics with different gate control systems

    International Nuclear Information System (INIS)

    Gula, V.; Cherepakhin, A.A.

    1982-01-01

    Some thyristor gate control systems both synchronous and nonsynchronous ones are described. The experimental results of supply voltage asymmetry influence on spectral contents of rectified. output voltage are quoted. Dynamic and frequency responses of these systems are investigated too. Results of comparison of the spectral content of 100 Hz subharmonic of rectified voltage on loading current showed the advantage of the systems with feedback [ru

  15. Temperature-gated thermal rectifier for active heat flow control.

    Science.gov (United States)

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

    2014-08-13

    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 (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.

  16. Control system for a superconducting rectifier using a microcomputer

    International Nuclear Information System (INIS)

    ten Kate, H.H.J.; Kamphuis, D.A.; Caspari, M.; van de Klundert, L.J.M.; Houkes, Z.

    1981-01-01

    Within the scope of a research program of superconducting rectifiers software is being developed to take care of the control of such systems. The hardware architecture which interferes with the in and output signals is based on a LSI-11/2 microprocessor with sufficient mass storage for data logging, console and printer. The flexibility inherent to this hardware configuration is desired for optimization of the rectifier concerning maximum current, power, efficiency and quench stability. The paper describes the structure of the program and the interaction between both computer hardware and software and the superconducting rectifier. However, because the reliability of computer systems is unsatisfactory, an additional hardware protection system still handles the most important alarms. 2 refs

  17. Stability analysis of direct current control in current source rectifier

    DEFF Research Database (Denmark)

    Lu, Dapeng; Wang, Xiongfei; Blaabjerg, Frede

    2017-01-01

    Current source rectifier with high switching frequency has a great potential for improving the power efficiency and power density in ac-dc power conversion. This paper analyzes the stability of direct current control based on the time delay effect. Small signal model including dynamic behaviors...

  18. Analysis and control of high power synchronous rectifier

    Energy Technology Data Exchange (ETDEWEB)

    Singh Tejinder.

    1993-01-01

    The description, steady state/dynamic analysis and control design of a high power synchronous rectifier is presented. The proposed rectifier system exploits selective harmonic elimination modulation techniques to minimize filtering requirements, and overcomes the dc voltage limitations of prior art equipment. A detailed derivation of the optimum pulse width modulation switching patterns, in the low frequency range for high power applications is presented. A general mathematical model of the rectifier is established which is non-linear and time-invariant. The transformation of reference frame and small signal linearization techniques are used to obtain closed form solutions from the mathematical model. The modelling procedure is verified by computer simulation. The closed loop design of the synchronous rectifier based on a phase and amplitude control strategy is investigated. The transfer functions derived from this analysis are used for the design of the regulators. The steady-state and dynamic results predicted by computer simulation are verified by PECAN. A systematic design procedure is developed and a detailed design example of a 1 MV-amp rectifer system is presented. 23 refs., 33 figs.

  19. Fully controlled 5-phase, 10-pulse, line commutated rectifier

    Directory of Open Access Journals (Sweden)

    Mahmoud I. Masoud

    2015-12-01

    Full Text Available The development and production of multiphase machines either generators or motors, specially five-phase, offers improved performance compared to three-phase counterpart. Five phase generators could generate power in applications such as, but not limited to, wind power generation, electric vehicles, aerospace, and oil and gas. The five-phase generator output requires converter system such as ac–dc converters. In this paper, a fully controlled 10-pulse line commutated rectifier, suitable to be engaged with wind energy applications, fed from five-phase source is introduced. A shunt active power filter (APF is used to improve power factor and supply current total harmonic distortion (THD. Compared to three-phase converters, 6-pulse or 12-pulse rectifiers, the 10-pulse rectifier engaged with 5-phase source alleviate their drawbacks such as high dc ripples and no need for electric gear or phase shifting transformer. MATLAB/SIMULINK platform is used as a simulation tool to investigate the performance of the proposed rectifier.

  20. Rectifier Current Control for an LLC Resonant Converter Based on a Simplified Linearized Model

    OpenAIRE

    Zhijian Fang; Junhua Wang; Shanxu Duan; Liangle Xiao; Guozheng Hu; Qisheng Liu

    2018-01-01

    In this paper, a rectifier current control for an LLC resonant converter is proposed, based on a simplified, two-order, linearized model that adds a rectifier current feedback inner loop to improve dynamic performance. Compared to the traditional large-signal model with seven resonant states, this paper utilizes a rectifier current state to represent the characteristics of the resonant states, simplifying the LLC resonant model from seven orders to two orders. Then, the rectifier current feed...

  1. Modelling a single phase voltage controlled rectifier using Laplace transforms

    Science.gov (United States)

    Kraft, L. Alan; Kankam, M. David

    1992-01-01

    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.

  2. Generalized space vector control for current source inverters and rectifiers

    Directory of Open Access Journals (Sweden)

    Roseline J. Anitha

    2016-06-01

    Full Text Available Current source inverters (CSI is one of the widely used converter topology in medium voltage drive applications due to its simplicity, motor friendly waveforms and reliable short circuit protection. The current source inverters are usually fed by controlled current source rectifiers (CSR with a large inductor to provide a constant supply current. A generalized control applicable for both CSI and CSR and their extension namely current source multilevel inverters (CSMLI are dealt in this paper. As space vector pulse width modulation (SVPWM features the advantages of flexible control, faster dynamic response, better DC utilization and easy digital implementation it is considered for this work. This paper generalizes SVPWM that could be applied for CSI, CSR and CSMLI. The intense computation involved in framing a generalized space vector control are discussed in detail. The algorithm includes determination of band, region, subregions and vectors. The algorithm is validated by simulation using MATLAB /SIMULINK for CSR 5, 7, 13 level CSMLI and for CSR fed CSI.

  3. Dynamic and Control Analysis of Modular Multi-Parallel Rectifiers (MMR)

    DEFF Research Database (Denmark)

    Zare, Firuz; Ghosh, Arindam; Davari, Pooya

    2017-01-01

    This paper presents dynamic analysis of a Modular Multi-Parallel Rectifier (MMR) based on state-space modelling and analysis. The proposed topology is suitable for high power application which can reduce line current harmonics emissions significantly. However, a proper controller is required...... to share and control current through each rectifier. Mathematical analysis and preliminary simulations have been carried out to verify the proposed controller under different operating conditions....

  4. Control Strategy of PWM Rectifiers Connected to Unbalanced Grids

    Czech Academy of Sciences Publication Activity Database

    Bejvl, Martin; Švec, J.; Tlustý, J.; Valouch, V.

    -, č. 11 (2013) ISSN 2172-038X. [International Conference on Renewable Energies and Power Quality (ICREPQ´13). Bilbao, 20.03.2013-22.03.2013] Institutional support: RVO:61388998 Keywords : electric power system * PWM rectifier * dc voltage ripple Subject RIV: JA - Electronics ; Optoelectronics, Electrical Engineering

  5. DEVELOPMENT OF CONTROLLED RECTIFIERS BASED ON THE BIPOLAR WITH STATIC INDUCTION TRANSISTORS (BSIT

    Directory of Open Access Journals (Sweden)

    F. I. Bukashev

    2016-01-01

    Full Text Available Aim. The aim of this study is to develop one of the most perspective semiconductor device suitable for creation and improvement of controlled rectifiers, bipolar static induction transistor.Methods. Considered are the structural and schematic circuit controlled rectifier based on bipolar static induction transistor (BSIT, and the criterion of effectiveness controlled rectifiers - equivalent to the voltage drop.Results. Presented are the study results of controlled rectifier layout on BSIT KT698I. It sets the layout operation at an input voltage of 2.0 V at a frequency up to 750 kHz. The efficiency of the studied layouts at moderate current densities as high as 90 % .Offered is optimization of technological route microelectronic controlled rectifier manufacturing including BSIT and integrated bipolar elements of the scheme management.Conclusion. It is proved that the most efficient use of the bipolar static induction transistor occurs at the low voltage controlled rectifiers 350-400 kHz, at frequencies in conjunction with a low-voltage control circuit.It is proved that the increase of the functional characteristics of the converters is connected to the expansion of the input voltage and output current ranges

  6. Predictive Duty Cycle Control of Three-Phase Active-Front-End Rectifiers

    DEFF Research Database (Denmark)

    Song, Zhanfeng; Tian, Yanjun; Chen, Wei

    2016-01-01

    This paper proposed an on-line optimizing duty cycle control approach for three-phase active-front-end rectifiers, aiming to obtain the optimal control actions under different operating conditions. Similar to finite control set model predictive control strategy, a cost function previously...

  7. Countermeasures for electrolytic corrosion - Part II: Implementation of a rapid potential-controlled rectifier

    Energy Technology Data Exchange (ETDEWEB)

    Ha, Tae-Hyun; Kim, Dae-Kyeong; Lee, Hyun-Goo; Ha, Yoon-Cheol; Bae, Jeong-Hyo [Underground Systems Group, Korea Electrotechnology Research Institute, 28-1 Sungju-dong, Changwon, 641-120 (Korea)

    2004-07-01

    In electrolytic interference circumstances such as underground pipelines in the vicinity of DC electrified railroads, drainage method or impressed current cathodic protection method has been widely used as a countermeasure for the electrolytic corrosion. In the former method, forced or polarized drainage is commonly adopted and in the latter, the phase-controlled rectifier with thyristor is in common use. Both methods, however, does not show as the optimal measure for the integrity of the pipeline, since the pipe-to-soil potential fluctuates highly positive to the cathodic protection criterion. In particular, as the potential of the pipeline near the railroad varies rapidly, a new rapidly responding countermeasure is necessary. In this paper, we introduce a new rapid potential controlled rectifier and report the result in field tests. Comparison with the existing forced drainage method is also made. The pipe-to-soil potential data show the effectiveness of the rapid potential-controlled rectifier. (authors)

  8. Modeling and control of three phase rectifier with electronic smoothing inductor

    DEFF Research Database (Denmark)

    Singh, Yash Veer; Rasmussen, Peter Omand; Andersen, Torben Ole

    2011-01-01

    This paper presents a simple, direct method for deriving the approximate, small-signal, average model and control strategy for three-phase diode bridge rectifier operating with electronic smoothing technique. Electronic smoothing inductor (ESI) performs the function of an inductor that has...... controlled variable impedance. This increases power factor (PF) and reduces total harmonic distortions (THDs) in mains current. The ESI based rectifier enables compact and cost effective design of three phase electric drive as size of passive components is reduced significantly. In order to carry out...

  9. Active and reactive power control of a current-source PWM-rectifier using space vectors

    Energy Technology Data Exchange (ETDEWEB)

    Salo, M.; Tuusa, H. [Tampere University of Technology (Finland). Department of Electrical Engineering, Power Electronics

    1997-12-31

    In this paper the current-source PWM-rectifier with active and reactive power control is presented. The control system is realized using space vector methods. Also, compensation of the reactive power drawn by the line filter is discussed. Some simulation results are shown. (orig.) 8 refs.

  10. Designing single phase Current-Programmed-Controlled rectifiers by harmonic currents

    DEFF Research Database (Denmark)

    Andersen, Gert Karmisholt; Blaabjerg, Frede

    2002-01-01

    The grid current harmonics of a Current-Programmed-Controlled (CPC) pfc rectifier strongly depends on the choice of switching frequency and switching inductance. This paper describes a new simple and vert fast method to calculate the grid current of a CPC controlled pfc converter. The method...

  11. Analysis of Three-Phase Rectifier Systems with Controlled DC-Link Current Under Unbalanced Grids

    DEFF Research Database (Denmark)

    Kumar, Dinesh; Davari, Pooya; Zare, Firuz

    2017-01-01

    Voltage unbalance is the most common disturbance in distribution networks, which give undesirable effects on many grid connected power electronics systems including Adjustable Speed Drive (ASD). Severe voltage unbalance can force three-phase rectifiers into almost single-phase operation, which...... degrades the grid power quality and also imposes a significant negative impact on the ASD system. This major power quality issue affecting the conventional rectifiers can be attenuated by controlling the DC-link current based on an Electronic Inductor (EI) technique. The purpose of this digest...... is to analyze and compare the performance of an EI with a conventional three-phase rectifier under unbalanced grid conditions. Experimental and simulation results validate the proposed mathematical modelling. Further analysis and benchmarking will be provided in the final paper....

  12. Rectifier Current Control for an LLC Resonant Converter Based on a Simplified Linearized Model

    Directory of Open Access Journals (Sweden)

    Zhijian Fang

    2018-03-01

    Full Text Available In this paper, a rectifier current control for an LLC resonant converter is proposed, based on a simplified, two-order, linearized model that adds a rectifier current feedback inner loop to improve dynamic performance. Compared to the traditional large-signal model with seven resonant states, this paper utilizes a rectifier current state to represent the characteristics of the resonant states, simplifying the LLC resonant model from seven orders to two orders. Then, the rectifier current feedback inner loop is proposed to increase the control system damping, improving dynamic performance. The modeling and design methodology for the LLC resonant converter are also presented in this paper. A frequency analysis is conducted to verify the accuracy of the simplified model. Finally, a 200 W LLC resonant converter prototype is built to verify the effectiveness of the proposed control strategy. Compared to a traditional single-loop controller, the settling time and voltage droop were reduced from 10.8 ms to 8.6 ms and from 6.8 V to 4.8 V, respectively, using the proposed control strategy.

  13. Impedance-based Analysis of DC Link Control in Voltage Source Rectifiers

    DEFF Research Database (Denmark)

    Lu, Dapeng; Wang, Xiongfei; Blaabjerg, Frede

    2018-01-01

    This paper analyzes the dynamics influences of the outer dc link control in the voltage source rectifiers based on the impedance model. The ac-dc interactions are firstly presented by means of full order small signal model in dq frame, which shows the input voltage and load condition are the two...

  14. WASTE MINIMIZATION ASSESSMENT FOR A MANUFACTURER OF SILICON-CONTROLLED RECTIFIERS AND SCHOTTKY RECTIFIERS

    Science.gov (United States)

    The U.S. Environmental Protection Agency (EPA) has funded a pilot project to assist small- and medium-size manufacturers who want to minimize their generation of waste but who lack the expertise to do so. In an effort to assist these manufacturers Waste Minimization Assessment Ce...

  15. CMOS single-stage input-powered bridge rectifier with boost switch and duty cycle control

    Science.gov (United States)

    Radzuan, Roskhatijah; Mohd Salleh, Mohd Khairul; Hamzah, Mustafar Kamal; Ab Wahab, Norfishah

    2017-06-01

    This paper presents a single-stage input-powered bridge rectifier with boost switch for wireless-powered devices such as biomedical implants and wireless sensor nodes. Realised using CMOS process technology, it employs a duty cycle switch control to achieve high output voltage using boost technique, leading to a high output power conversion. It has only six external connections with the boost inductance. The input frequency of the bridge rectifier is set at 50 Hz, while the switching frequency is 100 kHz. The proposed circuit is fabricated on a single 0.18-micron CMOS die with a space area of 0.024 mm2. The simulated and measured results show good agreement.

  16. Control of SiC Based Front-End Rectifier under Unbalanced Supply Voltage

    DEFF Research Database (Denmark)

    Maheshwari, Ramkrishan; Trintis, Ionut; Gohil, Ghanshyamsinh Vijaysinh

    2015-01-01

    A voltage source converter is used as a front end converter typically. In this paper, a converter which is realized using SiC MOSFET is considered. Due to SiC MOSFET, a switching frequency more than 50 kHz can be achieved. This can help increasing the current control loop bandwidth, which is not ...... together with a positive-sequence current controller for the front-end rectifier. A gain in the feedforward term can be changed to control the negative-sequence current. Simulation results are presented to verify the theory....

  17. High-performance digital triggering system for phase-controlled rectifiers

    International Nuclear Information System (INIS)

    Olsen, R.E.

    1983-01-01

    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

  18. Single Phase Current-Source Active Rectifier for Traction: Control System Design and Practical Problems

    Directory of Open Access Journals (Sweden)

    Jan Michalik

    2006-01-01

    Full Text Available This research has been motivated by industrial demand for single phase current-source active rectifier dedicated for reconstruction of older types of dc machine locomotives. This paper presents converters control structure design and simulations. The proposed converter control is based on the mathematical model and due to possible interaction with railway signaling and required low switching frequency employs synchronous PWM. The simulation results are verified by experimental tests performed on designed laboratory prototype of power of 7kVA

  19. Manufacturing Methods and Technology Measure for Fabrication of Silicon Transcalent Rectifier.

    Science.gov (United States)

    1980-09-01

    development and manufacturing as well as quality and reliability assurance of the 1 product. Marketing and Applications Engineering are responsible for...Prod Test/Eval’, z HA Kotler a Patent- Power & E 1 RM Roderick Env. Eng. & Test 1 JB Grosh Iron Mouptain - .l TUBE PARTS MFG. 5 RL SPALDING...Engineering Specification Request endorsed by authorized approvers from both Operations and Marketing . At this time, controlling Engineering Specifications

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

    Science.gov (United States)

    Lee, Hyung-Min; Ghovanloo, Maysam

    2011-01-01

    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-μm 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 Ω 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

  1. Design Research on Three-Phase PWM Rectifier Based on Double Closed Loop Control Technology

    Directory of Open Access Journals (Sweden)

    Guang Ya LIU

    2014-02-01

    Full Text Available Based on the high frequency of three-phase voltage source PWM rectifier, this paper established a mathematical model of three phase current inner ring and outer ring voltage, and put forward the setting method of three phase double closed loop control. Finally, it was verified through simulation. The experimental results show that Three-phase output of DC voltage is stable with the operation of regulating systems, the current flowing into the grid tends to be sinusoidal and power factor is close to 1, which greatly reduce the interference of harmonics on the grid, thus improve grid operation.

  2. Direct Power Control for Three-Phase Two-Level Voltage-Source Rectifiers Based on Extended-State Observation

    DEFF Research Database (Denmark)

    Song, Zhanfeng; Tian, Yanjun; Yan, Zhuo

    2016-01-01

    This paper proposed a direct power control strategy for three-phase two-level voltage-source rectifiers based on extended-state observation. Active and reactive powers are directly regulated in the stationary reference frame. Similar to the family of predictive controllers whose inherent characte......This paper proposed a direct power control strategy for three-phase two-level voltage-source rectifiers based on extended-state observation. Active and reactive powers are directly regulated in the stationary reference frame. Similar to the family of predictive controllers whose inherent...

  3. Structural basis of control of inward rectifier Kir2 channel gating by bulk anionic phospholipids.

    Science.gov (United States)

    Lee, Sun-Joo; Ren, Feifei; Zangerl-Plessl, Eva-Maria; Heyman, Sarah; Stary-Weinzinger, Anna; Yuan, Peng; Nichols, Colin G

    2016-09-01

    Inward rectifier potassium (Kir) channel activity is controlled by plasma membrane lipids. Phosphatidylinositol-4,5-bisphosphate (PIP2) binding to a primary site is required for opening of classic inward rectifier Kir2.1 and Kir2.2 channels, but interaction of bulk anionic phospholipid (PL(-)) with a distinct second site is required for high PIP2 sensitivity. Here we show that introduction of a lipid-partitioning tryptophan at the second site (K62W) generates high PIP2 sensitivity, even in the absence of PL(-) Furthermore, high-resolution x-ray crystal structures of Kir2.2[K62W], with or without added PIP2 (2.8- and 2.0-Å resolution, respectively), reveal tight tethering of the C-terminal domain (CTD) to the transmembrane domain (TMD) in each condition. Our results suggest a refined model for phospholipid gating in which PL(-) binding at the second site pulls the CTD toward the membrane, inducing the formation of the high-affinity primary PIP2 site and explaining the positive allostery between PL(-) binding and PIP2 sensitivity. © 2016 Lee et al.

  4. EMC Increasing of PWM Rectifier in Comparison with Classical Rectifier

    Directory of Open Access Journals (Sweden)

    R. Dolecek

    2008-12-01

    Full Text Available Pulse width modulated rectifier is a very popular topic nowadays. The modern industrial production demands continuous and lossless conversion of electrical energy parameters. This need leads to wide spread of power semiconductor converters. The rapid development in power electronics and microprocessor technology enables to apply sophisticated control methods that eliminate negative side effects of the power converters on the supply network. The phase controlled thyristor rectifiers overload the supply network with higher harmonics and reactive power consumption. That is why the PWM rectifier is being examined. In comparison with the phase controlled rectifier it can be controlled to consume nearly sinusoidal current with power factor equal to unity. Another advantage is its capability of energy recuperation. The PWM rectifier can assert itself for its good behavior in many applications, for example as an input rectifier in indirect frequency converter, or in traction. Traction vehicles equipped with PWM rectifier do not consume reactive power, do not load the supply network with higher harmonics, and the recuperation is possible. The paper deals with the PWM rectifier functional model realization and examination. Electromagnetic compatibility of PWM rectifier and classical phase controlled rectifier is compared on the basis of the input current harmonic analysis.

  5. Co-Design Method and Wafer-Level Packaging Technique of Thin-Film Flexible Antenna and Silicon CMOS Rectifier Chips for Wireless-Powered Neural Interface Systems

    Directory of Open Access Journals (Sweden)

    Kenji Okabe

    2015-12-01

    Full Text Available In this paper, a co-design method and a wafer-level packaging technique of a flexible antenna and a CMOS rectifier chip for use in a small-sized implantable system on the brain surface are proposed. The proposed co-design method optimizes the system architecture, and can help avoid the use of external matching components, resulting in the realization of a small-size system. In addition, the technique employed to assemble a silicon large-scale integration (LSI chip on the very thin parylene film (5 μm enables the integration of the rectifier circuits and the flexible antenna (rectenna. In the demonstration of wireless power transmission (WPT, the fabricated flexible rectenna achieved a maximum efficiency of 0.497% with a distance of 3 cm between antennas. In addition, WPT with radio waves allows a misalignment of 185% against antenna size, implying that the misalignment has a less effect on the WPT characteristics compared with electromagnetic induction.

  6. Co-Design Method and Wafer-Level Packaging Technique of Thin-Film Flexible Antenna and Silicon CMOS Rectifier Chips for Wireless-Powered Neural Interface Systems.

    Science.gov (United States)

    Okabe, Kenji; Jeewan, Horagodage Prabhath; Yamagiwa, Shota; Kawano, Takeshi; Ishida, Makoto; Akita, Ippei

    2015-12-16

    In this paper, a co-design method and a wafer-level packaging technique of a flexible antenna and a CMOS rectifier chip for use in a small-sized implantable system on the brain surface are proposed. The proposed co-design method optimizes the system architecture, and can help avoid the use of external matching components, resulting in the realization of a small-size system. In addition, the technique employed to assemble a silicon large-scale integration (LSI) chip on the very thin parylene film (5 μm) enables the integration of the rectifier circuits and the flexible antenna (rectenna). In the demonstration of wireless power transmission (WPT), the fabricated flexible rectenna achieved a maximum efficiency of 0.497% with a distance of 3 cm between antennas. In addition, WPT with radio waves allows a misalignment of 185% against antenna size, implying that the misalignment has a less effect on the WPT characteristics compared with electromagnetic induction.

  7. Nonlinear control techniques of a controllable rectifier/inverter-motor drive system with a small dc-link capacitor

    International Nuclear Information System (INIS)

    Liutanakul, Pisit; Pierfederici, Serge; Meibody-Tabar, Farid

    2008-01-01

    The necessity of the converters compactness in many applications imposes the reduction of their different components size when it is possible. In this paper, a control method allowing the use of a small size dc-link capacitor for the cascade of voltage controlled-rectifier/inverter-motor drive system is proposed. This is achieved by adding the power balance equation in the system's model and the application of an exact input/output feedback linearization technique in a way that the rectifier controller compensates any sudden change in the inverter load, which is here an induction motor. Since the exact input/output feedback linearization technique is sensitive to the uncertainties over system parameters, a robust control strategy based on sliding mode controller is proposed. By this approach, the dc-link voltage becomes almost insensitive to the load variations. As a result, the level of the dc-link voltage could be stabilized with a small size dc-link capacitor. Without any considerations of the RMS current stress on this dc-link capacitor, a calculation method of a minimum value of this capacitor based on its storage energy is proposed. All the investigations are shown by computer simulations and the performance of controlled system is verified by experimentation results

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

    DEFF Research Database (Denmark)

    Liserre, Marco; Blaabjerg, Frede; Hansen, Steffan

    2005-01-01

    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 a filter has been built and tested using the values obtained from this design. The experimental results demonstrate the performance of the design procedure both for the LCL filter and for the rectifier...... a powerful tool to design an LCL-filter-based active rectifier while avoiding trial-and-error procedures that can result in having to build several filter prototypes....

  9. Protocol converter for serial communication between digital rectifier controllers and a power plant SCADA system

    Directory of Open Access Journals (Sweden)

    Vukić Vladimir Đ.

    2016-01-01

    Full Text Available The paper describes the protocol converter INT-485-MBRTU, developed for serial communication between the thyristor rectifier (based on the proprietary protocol "INT-CPD-05", according to standard RS-485 and the SCADA system (based on protocol "Modbus RTU", of the same standard in the thermal power plant "Nikola Tesla B1". Elementary data on industrial communication protocols and communication gateways were provided. The basic technical characteristics of the "Omron" programmable logic controller CJ series were described, as well as the developed device INT-485-MBRTU. Protocol converters with two versions of communication software were tested, differing only in one control word, intended for a forced successive change of communication sequences, in opposite to automatic sequence relieve. The device iNT-485-MBRTU, with the program for forced successive change of communication sequences, demonstrated the reliability of data transfer of 100 %, in a sample of approximately 480 messages. For nearly the same sample, the same protocol converter, with a version of the program without any type of message identifiers, transferred less than 60 % of the foreseen data. During multiple sixty-hour tests, the reliability of data transfer of at least 99.9979% was recorded, in 100% of the analysed cases, and for a sample of nearly 96,000 pairs of the send and receive messages. We analysed the results and estimated the additional possibilities for application of the INT-485-MBRTU protocol converter.

  10. An Improved Current-Doubler Rectifier for the Marine Controlled Source Electromagnetic Transmitter

    Directory of Open Access Journals (Sweden)

    Hongxi Song

    2018-01-01

    Full Text Available High power marine controlled source electromagnetic transmitters have gained interest with applications in marine geological survey and mineral resources exploration. The direct current to direct current (DC-DC converter that is typically used in marine transmitters has some issues, as the insulated-gate bipolar transistor (IGBT tube cannot achieve zero-voltage switching (ZVS. In particular, lagging-leg switching cannot easily achieve ZVS. The conversion efficiency of the heat converter requires improvement. This paper proposes an improved current-doubler rectifier for the marine controlled source electromagnetic transmitter (ICDR-MCSET. Resonant inductance is increased and a blocking capacitor is added to the converter (DC-DC circuit, where the converter can achieve ZVS in a wide load range. This results in the effective decrease of the heating temperature and the improvement of transformation efficiency. Saber software simulation and a 20 KW electromagnetic transmitter are used to verify the results, which show that the method is feasible and effective.

  11. 5 kW bidirectional grid-connected drive using silicon-carbide switches: Control

    DEFF Research Database (Denmark)

    Kouchaki, Alireza; Lazar, Radu; Pedersen, Jacob Lykke

    2017-01-01

    his paper presents a controller design for a fully silicon-carbide (SiC) based bidirectional three-phase grid-connected PWM drive. For drive applications, controller must be robust and fast to be able to provide power flow in both directions. In this paper, proportional resonance (PR) current con...... magnet motor. Different tests will be conducted to evaluate the performance of the controllers in both generative and regenerative mode. It is shown that the controller can provide a good dynamic response to load changes for both direction of power flow.......-phase rectifier with switching frequency of 45 kHz will be tested. The test is done by connecting it to a grid simulator and the load is a resistive load. In the second test the rectifier will be connected to the grid via an auto-transformer and load is a 7.5kW SiC based drive which is connected to a permanent...

  12. Rectifier Filters

    Directory of Open Access Journals (Sweden)

    Y. A. Bladyko

    2010-01-01

    Full Text Available The paper contains definition of a smoothing factor which is suitable for any rectifier filter. The formulae of complex smoothing factors have been developed for simple and complex passive filters. The paper shows conditions for application of calculation formulae and filters. 

  13. Design and implementation of predictive current control of three-phase PWM rectifier using space-vector modulation (SVM)

    International Nuclear Information System (INIS)

    Bouafia, Abdelouahab; Gaubert, Jean-Paul; Krim, Fateh

    2010-01-01

    This paper is concerned with the design and implementation of current control of three-phase PWM rectifier based on predictive control strategy. The proposed predictive current control technique operates with constant switching frequency, using space-vector modulation (SVM). The main goal of the designed current control scheme is to maintain the dc-bus voltage at the required level and to achieve the unity power factor (UPF) operation of the converter. For this purpose, two predictive current control algorithms, in the sense of deadbeat control, are developed for direct controlling input current vector of the converter in the stationary α-β and rotating d-q reference frame, respectively. For both predictive current control algorithms, at the beginning of each switching period, the required rectifier average voltage vector allowing the cancellation of both tracking errors of current vector components at the end of the switching period, is computed and applied during a predefined switching period by means of SVM. The main advantages of the proposed predictive current control are that no need to use hysteresis comparators or PI controllers in current control loops, and constant switching frequency. Finally, the developed predictive current control algorithms were tested both in simulations and experimentally, and illustrative results are presented here. Results have proven excellent performance in steady and transient states, and verify the validity of the proposed predictive current control which is compared to other control strategies.

  14. Rectifier cabinet static breaker

    International Nuclear Information System (INIS)

    Costantino, R.A. Jr; Gliebe, R.J.

    1992-01-01

    A rectifier cabinet static breaker replaces a blocking diode pair with an SCR and the installation of a power transistor in parallel with the latch contactor to commutate the SCR to the off state. The SCR serves as a static breaker with fast turnoff capability providing an alternative way of achieving reactor scram in addition to performing the function of the replaced blocking diodes. The control circuitry for the rectifier cabinet static breaker includes on-line test capability and an LED indicator light to denote successful test completion. Current limit circuitry provides high-speed protection in the event of overload. 7 figs

  15. Rectifier cabinet static breaker

    Science.gov (United States)

    Costantino, Jr, Roger A.; Gliebe, Ronald J.

    1992-09-01

    A rectifier cabinet static breaker replaces a blocking diode pair with an SCR and the installation of a power transistor in parallel with the latch contactor to commutate the SCR to the off state. The SCR serves as a static breaker with fast turnoff capability providing an alternative way of achieving reactor scram in addition to performing the function of the replaced blocking diodes. The control circuitry for the rectifier cabinet static breaker includes on-line test capability and an LED indicator light to denote successful test completion. Current limit circuitry provides high-speed protection in the event of overload.

  16. Electron transport through rectifying self-assembled monolayer diodes on silicon: Fermi-level pinning at the molecule-metal interface.

    Science.gov (United States)

    Lenfant, S; Guerin, D; Tran Van, F; Chevrot, C; Palacin, S; Bourgoin, J P; Bouloussa, O; Rondelez, F; Vuillaume, D

    2006-07-20

    We report the synthesis and characterization of molecular rectifying diodes on silicon using sequential grafting of self-assembled monolayers of alkyl chains bearing a pi group at their outer end (Si/sigma-pi/metal junctions). We investigate the structure-performance relationships of these molecular devices, and we examine the extent to which the nature of the pi end group (change in the energy position of their molecular orbitals) drives the properties of these molecular diodes. Self-assembled monolayers of alkyl chains (different chain lengths from 6 to 15 methylene groups) functionalized by phenyl, anthracene, pyrene, ethylene dioxythiophene, ethylene dioxyphenyl, thiophene, terthiophene, and quaterthiophene were synthesized and characterized by contact angle measurements, ellipsometry, Fourier transform infrared spectroscopy, and atomic force microscopy. We demonstrate that reasonably well-packed monolayers are obtained in all cases. Their electrical properties were assessed by dc current-voltage characteristics and high-frequency (1-MHz) capacitance measurements. For all of the pi groups investigated here, we observed rectification behavior. These results extend our preliminary work using phenyl and thiophene groups (Lenfant et al., Nano Lett. 2003, 3, 741). The experimental current-voltage curves were analyzed with a simple analytical model, from which we extracted the energy position of the molecular orbital of the pi group in resonance with the Fermi energy of the electrodes. We report experimental studies of the band lineup in these silicon/alkyl pi-conjugated molecule/metal junctions. We conclude that Fermi-level pinning at the pi group/metal interface is mainly responsible for the observed absence of a dependence of the rectification effect on the nature of the pi groups, even though the groups examined were selected to have significant variations in their electronic molecular orbitals.

  17. Precision rectifier detectors for ac resistance bridge measurements with application to temperature control systems for irradiation creep experiments

    Energy Technology Data Exchange (ETDEWEB)

    Duncan, M. G.

    1977-05-01

    The suitability of several temperature measurement schemes for an irradiation creep experiment is examined. It is found that the specimen resistance can be used to measure and control the sample temperature if compensated for resistance drift due to radiation and annealing effects. A modified Kelvin bridge is presented that allows compensation for resistance drift by periodically checking the sample resistance at a controlled ambient temperature. A new phase-insensitive method for detecting the bridge error signals is presented. The phase-insensitive detector is formed by averaging the magnitude of two bridge voltages. Although this method is substantially less sensitive to stray reactances in the bridge than conventional phase-sensitive detectors, it is sensitive to gain stability and linearity of the rectifier circuits. Accuracy limitations of rectifier circuits are examined both theoretically and experimentally in great detail. Both hand analyses and computer simulations of rectifier errors are presented. Finally, the design of a temperature control system based on sample resistance measurement is presented. The prototype is shown to control a 316 stainless steel sample to within a 0.15/sup 0/C short term (10 sec) and a 0.03/sup 0/C long term (10 min) standard deviation at temperatures between 150 and 700/sup 0/C. The phase-insensitive detector typically contributes less than 10 ppM peak resistance measurement error (0.04/sup 0/C at 700/sup 0/C for 316 stainless steel or 0.005/sup 0/C at 150/sup 0/C for zirconium).

  18. Field-effect transistors as electrically controllable nonlinear rectifiers for the characterization of terahertz pulses

    Science.gov (United States)

    Lisauskas, Alvydas; Ikamas, Kestutis; Massabeau, Sylvain; Bauer, Maris; ČibiraitÄ--, DovilÄ--; Matukas, Jonas; Mangeney, Juliette; Mittendorff, Martin; Winnerl, Stephan; Krozer, Viktor; Roskos, Hartmut G.

    2018-05-01

    We propose to exploit rectification in field-effect transistors as an electrically controllable higher-order nonlinear phenomenon for the convenient monitoring of the temporal characteristics of THz pulses, for example, by autocorrelation measurements. This option arises because of the existence of a gate-bias-controlled super-linear response at sub-threshold operation conditions when the devices are subjected to THz radiation. We present measurements for different antenna-coupled transistor-based THz detectors (TeraFETs) employing (i) AlGaN/GaN high-electron-mobility and (ii) silicon CMOS field-effect transistors and show that the super-linear behavior in the sub-threshold bias regime is a universal phenomenon to be expected if the amplitude of the high-frequency voltage oscillations exceeds the thermal voltage. The effect is also employed as a tool for the direct determination of the speed of the intrinsic TeraFET response which allows us to avoid limitations set by the read-out circuitry. In particular, we show that the build-up time of the intrinsic rectification signal of a patch-antenna-coupled CMOS detector changes from 20 ps in the deep sub-threshold voltage regime to below 12 ps in the vicinity of the threshold voltage.

  19. Semi-conductor rectifiers

    International Nuclear Information System (INIS)

    1981-01-01

    A method is described for treating a semiconductor rectifier, comprising: heating the rectifier to a temperature in the range of 100 0 C to 500 0 C, irradiating the rectifier while maintaining its temperature within the said range, and then annealing the rectifier at a temperature of between 280 0 C and 350 0 C for between two and ten hours. (author)

  20. Automatic Control of Silicon Melt Level

    Science.gov (United States)

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

    1982-01-01

    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.

  1. Balanced Current Control Strategy for Current Source Rectifier Stage of Indirect Matrix Converter under Unbalanced Grid Voltage Conditions

    Directory of Open Access Journals (Sweden)

    Yeongsu Bak

    2016-12-01

    Full Text Available This paper proposes a balanced current control strategy for the current source rectifier (CSR stage of an indirect matrix converter (IMC under unbalanced grid voltage conditions. If the three-phase grid connected to the voltage source inverter (VSI of the IMC has unbalanced voltage conditions, it affects the currents of the CSR stage and VSI stage, and the currents are distorted. Above all, the distorted currents of the CSR stage cause instability in the overall system, which can affect the life span of the system. Therefore, in this paper, a control strategy for balanced currents in the CSR stage is proposed. To achieve balanced currents in the CSR stage, the VSI stage should receive DC power without ripple components from the CSR stage. This is implemented by controlling the currents in the VSI stage. Therefore, the proposed control strategy decouples the positive and negative phase-sequence components existing in the unbalanced voltages and currents of the VSI stage. Using the proposed control strategy under unbalanced grid voltage conditions, the stability and life span of the overall system can be improved. The effectiveness of the proposed control strategy is verified by simulation and experimental results.

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

    Science.gov (United States)

    Birchenough, A. G.

    1971-01-01

    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.

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

    Science.gov (United States)

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

    1986-01-01

    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.

  4. High Efficiency Three-phase Power Factor Correction Rectifier using Wide Band-Gap Devices

    DEFF Research Database (Denmark)

    Kouchaki, Alireza

    Improving the conversion efficiency of power factor correction (PFC) rectifiers has become compelling due to their wide applications such as adjustable speed drives, uninterruptible power supplies (UPS), and battery chargers for electric vehicles (EVs). The attention to PFCs has increased even more....... Therefore, current controllers are also important to be investigated in this project. In this PhD research work, a comprehensive design of a two-level three-phase PFC rectifier using silicon-carbide (SiC) switches to achieve high efficiency is presented. The work is divided into two main parts: 1) Optimum...

  5. Silicon Sheet Quality is Improved By Meniscus Control

    Science.gov (United States)

    Yates, D. A.; Hatch, A. E.; Goldsmith, J. M.

    1983-01-01

    Better quality silicon crystals for solar cells are possible with instrument that monitors position of meniscus as sheet of solid silicon is drawn from melt. Using information on meniscus height, instrument generates feedback signal to control melt temperature. Automatic control ensures more uniform silicon sheets.

  6. Design Criteria for DC Link Filters in a Synchronous Generator-Phase Controlled Rectifier-Filter-Load System

    National Research Council Canada - National Science Library

    Greseth, Gregory

    1999-01-01

    .... The proposed Navy DC Zonal Electrical Distribution System (DC ZEDS) being designed for the new DD-21 utilizes a rectified ac generator output which is filtered and stepped to usable voltages by local dc-dc converters...

  7. Direct-current vector control of three-phase grid-connected rectifier-inverter

    Energy Technology Data Exchange (ETDEWEB)

    Li, Shuhui; Haskew, Timothy A.; Hong, Yang-Ki; Xu, Ling [Department of Electrical and Computer Engineering, University of Alabama, Tuscaloosa, AL 35475 (United States)

    2011-02-15

    The three-phase grid-connected converter is widely used in renewable and electric power system applications. Traditionally, control of the three-phase grid-connected converter is based on the standard decoupled d-q vector control mechanism. Nevertheless, the study of this paper shows that there is a limitation in the conventional standard vector control method. Some of the limitations have also been found recently by other researchers. To overcome the shortage of the conventional vector control technique, this paper proposes a new direct-current d-q vector control mechanism in a nested-loop control structure, based on which an optimal control strategy is developed in a nonlinear programming formulation. The behaviors of both the conventional and proposed control methods are compared and evaluated in simulation and laboratory hardware experiment environments, both of which demonstrates that the proposed approach is effective for grid-connected power converter control in a wide system conditions while the conventional standard vector control approach may behave improperly especially when the converter operates beyond its PWM saturation limit. (author)

  8. Fuzzy control techniques applied to a three phase synchronous rectifier current loop

    Directory of Open Access Journals (Sweden)

    Alberto Berzoy-Lleren

    2015-01-01

    Full Text Available Este trabajo presenta tres técnicas de control difuso de estructura variable (FVSC aplicadas al lazo de control de corriente en un rectificador síncrono trifásico. Estas técnicas se basan en un controlador PI difuso Takagi-Sugeno (T-S. El primer controlador es un FVSC de primer orden que se usa como referencia. A continuación se presentan y prueban dos estrategias FVSC, FVSC de segundo y tercer orden. Estos esquemas de control se simulan primero y luego se prueban en un rectificador síncrono de propósito general de laboratorio. Los resultados experimentales muestran que el rendimiento del control es bueno en los tres esquemas, logrando compensación de las corrientes armónicas y corrección del factor de potencia.

  9. Passivity-based harmonic control through series/parallel damping of an H-bridge rectifier

    NARCIS (Netherlands)

    De Vries, M. M. J.; Kransse, M. J.; Liserre, M.; Monopoli, V. G.; Scherpen, J. M. A.

    2007-01-01

    Nowadays the H-bridge is one of the preferred solutions to connect DC loads or distributed sources to the single-phase grid. The control aims are: sinusoidal grid current with unity power factor and optimal DC voltage regulation capability. These objectives should be satisfied, regardless the

  10. Control Techniques of Grid Connected PWM Rectifiers under Unbalanced Input Voltage Conditions

    Czech Academy of Sciences Publication Activity Database

    Bejvl, Martin; Šimek, Petr; Škramlík, Jiří; Valouch, Viktor

    2013-01-01

    Roč. 2, č. 1 (2013), s. 10-21 ISSN 1805-3386 R&D Projects: GA MPO(CZ) FR-TI1/330 Institutional support: RVO:61388998 Keywords : phase locked loop (PLL) * DSC * current control ler Subject RIV: JA - Electronics ; Optoelectronics, Electrical Engineering

  11. Polarization Control for Silicon Photonic Circuits

    Science.gov (United States)

    Caspers, Jan Niklas

    In recent years, the field of silicon photonics has received much interest from researchers and companies across the world. The idea is to use photons to transmit information on a computer chip in order to increase computational speed while decreasing the power required for computation. To allow for communication between the chip and other components, such as the computer memory, these silicon photonics circuits need to be interfaced with optical fiber. Unfortunately, in order to interface an optical fiber with an integrated photonics circuit two major challenges need to be overcome: a mode-size mismatch as well as a polarization mismatch. While the problem of mode-size has been well investigated, the polarization mismatch has yet to be addressed. In order to solve the polarization mismatch one needs to gain control over the polarization of the light in a waveguide. In this thesis, I will present the components required to solve the polarization mismatch. Using a novel wave guiding structure, the hybrid plasmonic waveguide, an ultra-compact polarization rotator is designed, fabricated, and tested. The hybrid plasmonic rotator has a performance similar to purely dielectric rotators while being more than an order of magnitude smaller. Additionally, a broadband hybrid plasmonic coupler is designed and measured. This coupler has a performance similar to dielectric couplers while having a footprint an order of magnitude smaller. Finally, a system solution to the polarization mismatch is provided. The system, a polarization adapter, matches the incoming changing polarization from the fiber actively to the correct one of the silicon photonics circuit. The polarization adapter is demonstrated experimentally to prove its operation. This proof is based on dielectric components, but the aforementioned hybrid plasmonic waveguide components would make the system more compact.

  12. Low-Complexity Model Predictive Control of Single-Phase Three-Level Rectifiers with Unbalanced Load

    DEFF Research Database (Denmark)

    Ma, Junpeng; Song, Wensheng; Wang, Xiongfei

    2018-01-01

    The fluctuation of the neutral-point potential in single-phase three-level rectifiers leads to coupling between the line current regulation and dc-link voltage balancing, deteriorating the quality of line current. For addressing this issue, this paper proposes a low-complexity model predictive...

  13. SPS rectifier stations

    CERN Multimedia

    CERN PhotoLab

    1974-01-01

    The first of the twelves SPS rectifier stations for the bending magnets arrived at CERN at the end of the year. The photograph shows a station with the rectifiers on the left and in the other three cubicles the chokes, capacitors and resistor of the passive filter.

  14. Design and implementation of high performance direct power control of three-phase PWM rectifier, via fuzzy and PI controller for output voltage regulation

    International Nuclear Information System (INIS)

    Bouafia, Abdelouahab; Krim, Fateh; Gaubert, Jean-Paul

    2009-01-01

    This paper proposes direct power control (DPC) for three-phase PWM rectifiers using a new switching table, without line voltage sensors. The instantaneous active and reactive powers, directly controlled by selecting the optimum state of the converter, are used as the PWM control variables instead of the phase line currents being used. The main goal of the control system is to maintain the dc-bus voltage at the required level, while input currents drawn from the power supply should be sinusoidal and in phase with respective phase voltages to satisfy the unity power factor (UPF) operation. Conventional PI and a designed fuzzy logic-based controller, in the dc-bus voltage control loop, have been used to provide active power command. A dSPACE based experimental system was developed to verify the validity of the proposed DPC. The steady-state, and dynamic results illustrating the operation and performance of the proposed control scheme are presented. As a result, it was confirmed that the novel DPC is much better than the classical one. Line currents very close to sinusoidal waveforms (THD < 2%) and good regulation of dc-bus voltage are achieved using PI or fuzzy controller. Moreover, fuzzy logic controller gives excellent performance in transient state, a good rejection of impact load disturbance, and a good robustness

  15. Full-wave current conveyor precision rectifier

    Directory of Open Access Journals (Sweden)

    Đukić Slobodan R.

    2008-01-01

    Full Text Available A circuit that provides precision rectification of small signal with low temperature sensitivity for frequencies up to 100 kHz without waveform distortion is presented. It utilizes an improved second type current conveyor based on current-steering output stage and biased silicon diodes. The use of a DC current source to bias the rectifying diodes provides higher temperature stability and lower DC offset level at the output. Proposed design of the precision rectifier ensures good current transfer linearity in the range that satisfy class A of the amplifier and good voltage transfer characteristic for low level signals. Distortion during the zero crossing of the input signal is practically eliminated. Design of the proposed rectifier is realized with standard components.

  16. Solid state circuit controls direction, speed, and braking of dc motor

    Science.gov (United States)

    Hanna, M. F.

    1966-01-01

    Full-wave bridge rectifier circuit controls the direction, speed, and braking of a dc motor. Gating in the circuit of Silicon Controlled Rectifiers /SCRS/ controls output polarity and braking is provided by an SCR that is gated to short circuit the reverse voltage generated by reversal of motor rotation.

  17. The LHCb Silicon Tracker - Control system specific tools and challenges

    CERN Document Server

    Adeva, G; Esperante Pereira, D; Gallas, A; Pazos Alvarez, A; Perez Trigo, E; Rodriguez Perez, P; Saborido, J; Amhis, Y; Bay, A; Blanc, F; Bressieux, J; Conti, G; Dupertuis, F; Fave, V; Frei, R; Gauvin, N; Haefeli, G; Keune, A; Luisier, J; Marki, R; Muresan, R; Nakada, T; Needham, M; Knecht, M; Schneider, O; Tran, M; Anderson, J; Buechler, A; Bursche, A; Chiapolini, N; De Cian, M; Elsasser, C; Salzmann, C; Saornil Gamarra, S; Steiner, S; Steinkamp, O; Straumann, U; van Tilburg, J; Tobin, M; Vollhardt, A; Aquines Gutierrez, O; Bauer, C; Britsch, M; Maciuc, F; Schmelling, M; Voss, H; Iakovenko, V; Okhrimenko, O; Pugatch, V

    2014-01-01

    The Experiment Control System (ECS) of the LHCb Silicon Tracker sub-detectors is built on the integrated LHCb ECS framework. Although all LHCb sub-detectors use the same framework and follow the same guidelines, the Silicon Tracker control system uses some interesting additional features in terms of operation and monitoring. The main details are described in this document. Since its design, the Silicon Tracker control system has been continuously evolving in a quite disorganized way. Some major maintenance activities are required to be able to keep improving. A description of those activities can also be found here.

  18. Manufacture of the rectifier of the HT-7U PFPS

    International Nuclear Information System (INIS)

    Gao Ge; Fu Peng; Tang Lunjun; Wang Linsen

    2005-01-01

    The rectifiers of the HT-7U poloidal field power supply (PFPS) are introduced. A new control method, four quadrants converter, is brought forward, which overcomes the short-coming of both the circulating current mode and the non-circulating current mode. This control mode also resolves the problem of DC circulating current in the identical phase anti-parallel connection rectifiers when these rectifiers run in the circulating current mode. (authors)

  19. Structurally controlled deposition of silicon onto nanowires

    Science.gov (United States)

    Wang, Weijie; Liu, Zuqin; Han, Song; Bornstein, Jonathan; Stefan, Constantin Ionel

    2018-03-20

    Provided herein are nanostructures for lithium ion battery electrodes and methods of fabrication. In some embodiments, a nanostructure template coated with a silicon coating is provided. The silicon coating may include a non-conformal, more porous layer and a conformal, denser layer on the non-conformal, more porous layer. In some embodiments, two different deposition processes, e.g., a PECVD layer to deposit the non-conformal layer and a thermal CVD process to deposit the conformal layer, are used. Anodes including the nanostructures have longer cycle lifetimes than anodes made using either a PECVD or thermal CVD method alone.

  20. Topology optimization of viscoelastic rectifiers

    DEFF Research Database (Denmark)

    Jensen, Kristian Ejlebjærg; Szabo, Peter; Okkels, Fridolin

    2012-01-01

    An approach for the design of microfluidic viscoelastic rectifiers is presented based on a combination of a viscoelastic model and the method of topology optimization. This presumption free approach yields a material layout topologically different from experimentally realized rectifiers...

  1. Harmonic Distortion Performance of Multi Three-Phase SCR-Fed Drive Systems with Controlled DC-Link Current under Unbalanced Grid

    DEFF Research Database (Denmark)

    Soltani, Hamid; Davari, Pooya; Blaabjerg, Frede

    2017-01-01

    . In this paper, the main aim is to analyze the effects of the grid unbalanced voltage on the multi-unit three-phase ASDs with the Silicon-Controlled Rectifier (SCR)-fed front-end rectifiers, where the DC-link current is controlled utilizing an Electronic Inductor (EI) technique. In this respect, the main...

  2. DC Motor Drive with PFC Rectifier

    Directory of Open Access Journals (Sweden)

    Lascu Mihaela

    2008-05-01

    Full Text Available The goal of this work is to study theperformances of a hybrid controller used to controlDC Motor drive with a single-phase power factorcorrection rectifier. This study is made usingcomputer simulation (Simulink. The first part isdevoted to the control system of the DC Motors. Inthe second part, the design of the hybrid controllerwill be presented. The third part is the design ofthe fast response single-phase boost power factorcorrection rectifier. The last parts are devoted tosimulation and experimental results.

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

    Science.gov (United States)

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

    2014-04-01

    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.

  4. Solid state thermal rectifier

    Science.gov (United States)

    None

    2016-07-05

    Thermal rectifiers using linear nanostructures as core thermal conductors have been fabricated. A high mass density material is added preferentially to one end of the nanostructures to produce an axially non-uniform mass distribution. The resulting nanoscale system conducts heat asymmetrically with greatest heat flow in the direction of decreasing mass density. Thermal rectification has been demonstrated for linear nanostructures that are electrical insulators, such as boron nitride nanotubes, and for nanostructures that are conductive, such as carbon nanotubes.

  5. Quality evaluation of resistivity-controlled silicon crystals

    Science.gov (United States)

    Wang, Jong Hoe

    2006-01-01

    The segregation phenomenon of dopants causes a low production yield of silicon crystal that meets the resistivity tolerance required by device manufacturers. In order to control the macroscopic axial resistivity distribution in bulk crystal growth, numerous studies including continuous Czochralski method and double crucible technique have been studied. The simple B-P codoping method for improving the productivity of p-type silicon single-crystal growth by controlling axial specific resistivity distribution was proposed by Wang [Jpn. J. Appl. Phys. 43 (2004) 4079]. In this work, the quality of Czochralski-grown silicon single crystals with a diameter 200 mm using B-P codoping method was studied from the chemical and structural points of view. It was found that the characteristics of B-P codoped wafers including the oxygen precipitation behavior and the grown-in defects are same as that of conventional B-doped Czochralski crystals.

  6. A silicon central pattern generator controls locomotion in vivo.

    Science.gov (United States)

    Vogelstein, R J; Tenore, F; Guevremont, L; Etienne-Cummings, R; Mushahwar, V K

    2008-09-01

    We present a neuromorphic silicon chip that emulates the activity of the biological spinal central pattern generator (CPG) and creates locomotor patterns to support walking. The chip implements ten integrate-and-fire silicon neurons and 190 programmable digital-to-analog converters that act as synapses. This architecture allows for each neuron to make synaptic connections to any of the other neurons as well as to any of eight external input signals and one tonic bias input. The chip's functionality is confirmed by a series of experiments in which it controls the motor output of a paralyzed animal in real-time and enables it to walk along a three-meter platform. The walking is controlled under closed-loop conditions with the aide of sensory feedback that is recorded from the animal's legs and fed into the silicon CPG. Although we and others have previously described biomimetic silicon locomotor control systems for robots, this is the first demonstration of a neuromorphic device that can replace some functions of the central nervous system in vivo.

  7. The ALICE Silicon Pixel Detector Control and Calibration Systems

    CERN Document Server

    Calì, Ivan Amos; Manzari, Vito; Stefanini, Giorgio

    2008-01-01

    The work presented in this thesis was carried out in the Silicon Pixel Detector (SPD) group of the ALICE experiment at the Large Hadron Collider (LHC). The SPD is the innermost part (two cylindrical layers of silicon pixel detec- tors) of the ALICE Inner Tracking System (ITS). During the last three years I have been strongly involved in the SPD hardware and software development, construction and commissioning. This thesis is focused on the design, development and commissioning of the SPD Control and Calibration Systems. I started this project from scratch. After a prototyping phase now a stable version of the control and calibration systems is operative. These systems allowed the detector sectors and half-barrels test, integration and commissioning as well as the SPD commissioning in the experiment. The integration of the systems with the ALICE Experiment Control System (ECS), DAQ and Trigger system has been accomplished and the SPD participated in the experimental December 2007 commissioning run. The complex...

  8. MPC-SVM method for Vienna rectifier with PMSG used in Wind Turbine Systems

    DEFF Research Database (Denmark)

    Lee, June-Seok; Bak, Yeongsu; Lee, Kyo-Beum

    2016-01-01

    Using a Vienna rectifier as the machine-side rectifier of back-to-back converter is advantageous in terms of size and cost compared to three-level topologies and for this reason, the Vienna rectifier has been used in Wind Turbine Systems (WTS). This paper proposes a Model Predictive Control (MPC......) method for the Vienna rectifier used in WTS with a Permanent Magnet Synchronous Generator (PMSG). The proposed MPC method considers the feasible eight-voltage vectors of the Vienna rectifier. In addition, the voltage vectors, which are the center voltage vectors of two feasible adjacent voltage vectors...

  9. Controlling growth density and patterning of single crystalline silicon nanowires

    International Nuclear Information System (INIS)

    Chang, Tung-Hao; Chang, Yu-Cheng; Liu, Fu-Ken; Chu, Tieh-Chi

    2010-01-01

    This study examines the usage of well-patterned Au nanoparticles (NPs) as a catalyst for one-dimensional growth of single crystalline Si nanowires (NWs) through the vapor-liquid-solid (VLS) mechanism. The study reports the fabrication of monolayer Au NPs through the self-assembly of Au NPs on a 3-aminopropyltrimethoxysilane (APTMS)-modified silicon substrate. Results indicate that the spin coating time of Au NPs plays a crucial role in determining the density of Au NPs on the surface of the silicon substrate and the later catalysis growth of Si NWs. The experiments in this study employed optical lithography to pattern Au NPs, treating them as a catalyst for Si NW growth. The patterned Si NW structures easily produced and controlled Si NW density. This approach may be useful for further studies on single crystalline Si NW-based nanodevices and their properties.

  10. A Novel High Bandwidth Current Control Strategy for SiC mosfet Based Active Front-End Rectifiers Under Unbalanced Input Voltage Conditions

    DEFF Research Database (Denmark)

    Maheshwari, Ramkrishan; Trintis, Ionut; Török, Lajos

    2017-01-01

    SiC mosfet based converters are capable of high switching frequency operation. In this paper, the converter is operated with 50-kHz switching frequency for an active front-end rectifier application. Due to high switching frequency, the grid-side filter size is reduced, and the possibility of a high...

  11. Synchronous Half-Wave Rectifier

    Science.gov (United States)

    Rippel, Wally E.

    1989-01-01

    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.

  12. The harmonic composition of the output voltage of a rectifier unit with a PWM voltage booster converter.

    OpenAIRE

    ПАНЧЕНКО, В В

    2015-01-01

    The author investigates a rectifier unit constructed on the basis of cascade connection of the main non-controlled m-pulse rectifier and PWM voltage booster converter. The research presents the analysis of the harmonic composition of the output voltage of a rectifier unit with a PWM voltage booster converter on completely controlled keys. The dependence of the relative harmonic amplitude on the commutation corner is defined. The estimation of a rectifier unit electromagnetic compatibility wit...

  13. 19 rectifiers to supply the coils of the TCV tokamak

    International Nuclear Information System (INIS)

    Fasel, D.; Perez, A.; Depreville, G.; Puchar, F.; Pahud, J.D.

    1990-01-01

    This paper describes the electrical network designed to supply the 19 coils of the TCV (Tokamak a Configuration Variable) tokamak. After a brief description of the main purpose of TCV, the general characteristics of the TCV network are given. Then the technical choices made for the rectifier power stage are detailed. There follows a description of the rectifier digital control electronics. Comments on simulations carried out and the actual status conclude the paper. (author) 3 refs., 5 figs., 2 tabs

  14. Automatically controlled facilities for irradiation of silicon crystals at the Rossendorf Research Reactor

    International Nuclear Information System (INIS)

    Ross, R.

    1988-01-01

    This report describes the facilities for neutron transmutation doping of silicon in GDR. The irradiation of silicon single crystals began at Rossendorf in 1978 with simple equipment. Only a small amount of silicon could be irradiated in it. The fast increasing need of NTD-silicon made it necessary to design and construct new and better facilities. The new facilities are capable of irradiating silicon from 2'' to 3'' in diameter. The irradiation process takes place automatically with the assistance of a computer. Material produced has an axial homogeneity of ± 7%. Irradiation riggs, techniques, irradiation control and quality control are discussed. (author). 4 figs

  15. Controlled delivery of acyclovir from porous silicon micro- and nanoparticles

    Energy Technology Data Exchange (ETDEWEB)

    Maniya, Nalin H.; Patel, Sanjaykumar R.; Murthy, Z.V.P., E-mail: zvpm2000@yahoo.com

    2015-03-01

    Graphical abstract: - Highlights: • Porous silicon (PSi) was fabricated by electrochemical etching process. • Micro- and nanoparticles were prepared by ultrasonic fracture of PSi films. • Acyclovir was loaded into native, oxidized, and hydrosilylated PSi particles. • Micro- and nanoparticles displays controlled release behaviour for several days. • Drug release behaviour and release kinetics from PSi particles were studied. - Abstract: In this work, micro- and nanoparticles of porous silicon (PSi) are demonstrated to act as effective carrier for the controlled delivery of acyclovir (ACV). PSi films prepared by electrochemical etching were fractured by ultrasonication to prepare micro- and nanoparticles. PSi native particles were thermally oxidized (TOPSi) and thermally hydrosilylated using undecylenic acid (UnPSi). PSi particles with three different surface chemistries were then loaded with ACV by physical adsorption and covalent attachment. Such particles were characterized by scanning electron microscopy, dynamic light scattering, and Fourier transform infrared spectroscopy. In vitro ACV release experiments in phosphate buffered saline showed sustained release behaviour from both micro- and nanoparticles and order of release was found to be native PSi > TOPSi > UnPSi. Drug release kinetics study using Korsmeyer-Peppas model suggested a combination of both drug diffusion and Si scaffold erosion based drug release mechanisms.

  16. Controlled delivery of acyclovir from porous silicon micro- and nanoparticles

    International Nuclear Information System (INIS)

    Maniya, Nalin H.; Patel, Sanjaykumar R.; Murthy, Z.V.P.

    2015-01-01

    Graphical abstract: - Highlights: • Porous silicon (PSi) was fabricated by electrochemical etching process. • Micro- and nanoparticles were prepared by ultrasonic fracture of PSi films. • Acyclovir was loaded into native, oxidized, and hydrosilylated PSi particles. • Micro- and nanoparticles displays controlled release behaviour for several days. • Drug release behaviour and release kinetics from PSi particles were studied. - Abstract: In this work, micro- and nanoparticles of porous silicon (PSi) are demonstrated to act as effective carrier for the controlled delivery of acyclovir (ACV). PSi films prepared by electrochemical etching were fractured by ultrasonication to prepare micro- and nanoparticles. PSi native particles were thermally oxidized (TOPSi) and thermally hydrosilylated using undecylenic acid (UnPSi). PSi particles with three different surface chemistries were then loaded with ACV by physical adsorption and covalent attachment. Such particles were characterized by scanning electron microscopy, dynamic light scattering, and Fourier transform infrared spectroscopy. In vitro ACV release experiments in phosphate buffered saline showed sustained release behaviour from both micro- and nanoparticles and order of release was found to be native PSi > TOPSi > UnPSi. Drug release kinetics study using Korsmeyer-Peppas model suggested a combination of both drug diffusion and Si scaffold erosion based drug release mechanisms

  17. Control and data acquisition electronics for the CDF Silicon Vertex Detector

    Energy Technology Data Exchange (ETDEWEB)

    Turner, K.J.; Nelson, C.A.; Shaw, T.M.; Wesson, T.R.

    1991-11-01

    A control and data acquisition system has been designed for the CDF Silicon Vertex Detector (SVX) at Fermilab. The system controls the operation of the SVX Rev D integrated circuit (SVX IC) that is used to instrument a 46,000 microstrip silicon detector. The system consists of a Fastbus Sequencer, a Crate Controller and Digitizer modules. 11 refs., 6 figs., 3 tabs.

  18. Control and data acquisition electronics for the CDF silicon vertex detector

    International Nuclear Information System (INIS)

    urner, K.J.; Nelson, C.A.; Shaw, T.M.; Wesson, T.R.

    1992-01-01

    This paper reports on a control and data acquisition system that has been designed for the CDF Silicon Vertex Detector (SVX) at Fermilab. The system controls the operation of the SVX Rev D integrated circuit (SVX IC) that is used to instrument a 46,000 microstrip silicon detector. The system consists of a Fastbus Sequencer, a Crate Controller and Digitizer modules

  19. Control and data acquisition electronics for the CDF Silicon Vertex Detector

    International Nuclear Information System (INIS)

    Turner, K.J.; Nelson, C.A.; Shaw, T.M.; Wesson, T.R.

    1991-11-01

    A control and data acquisition system has been designed for the CDF Silicon Vertex Detector (SVX) at Fermilab. The system controls the operation of the SVX Rev D integrated circuit (SVX IC) that is used to instrument a 46,000 microstrip silicon detector. The system consists of a Fastbus Sequencer, a Crate Controller and Digitizer modules. 11 refs., 6 figs., 3 tabs

  20. Controlled delivery of acyclovir from porous silicon micro- and nanoparticles

    Science.gov (United States)

    Maniya, Nalin H.; Patel, Sanjaykumar R.; Murthy, Z. V. P.

    2015-03-01

    In this work, micro- and nanoparticles of porous silicon (PSi) are demonstrated to act as effective carrier for the controlled delivery of acyclovir (ACV). PSi films prepared by electrochemical etching were fractured by ultrasonication to prepare micro- and nanoparticles. PSi native particles were thermally oxidized (TOPSi) and thermally hydrosilylated using undecylenic acid (UnPSi). PSi particles with three different surface chemistries were then loaded with ACV by physical adsorption and covalent attachment. Such particles were characterized by scanning electron microscopy, dynamic light scattering, and Fourier transform infrared spectroscopy. In vitro ACV release experiments in phosphate buffered saline showed sustained release behaviour from both micro- and nanoparticles and order of release was found to be native PSi > TOPSi > UnPSi. Drug release kinetics study using Korsmeyer-Peppas model suggested a combination of both drug diffusion and Si scaffold erosion based drug release mechanisms.

  1. Creating and Controlling Single Spins in Silicon Carbide

    Science.gov (United States)

    Christle, David

    Silicon carbide (SiC) is a well-established commercial semiconductor used in high-power electronics, optoelectronics, and nanomechanical devices, and has recently shown promise for semiconductor-based implementations of quantum information technologies. In particular, a set of divacancy-related point defects have improved coherence properties relative to the prominent nitrogen-vacancy center in diamond, are addressable at near-telecom wavelengths, and reside in a material for which there already exist advanced growth, doping, and microfabrication capabilities. These properties suggest divacancies in SiC have compelling advantages for photonics and micromechanical applications, yet their relatively recent discovery means crucial aspects of their fundamental physics for these applications are not well understood. I will review our progress on manipulating spin defects in SiC, and discuss efforts towards isolating and controlling them at the single defect limit. In particular, our most recent experimental results demonstrate isolation and control of long-lived (T2 = 0 . 9 ms) divacancies in a form of SiC that can be grown epitaxially on silicon. By studying the time-resolved photoluminescence of a single divacancy, we reveal its fundamental orbital structure and characterize in detail the dynamics of its special optical cycle. Finally, we probe individual divacancies using resonant laser techniques and reveal an efficient spin-photon interface with figures of merit comparable to those reported for NV centers in diamond. These results suggest a pathway towards photon-mediated entanglement of SiC defect spins over long distances. This work was supported by NSF, AFOSR, the Argonne CNM, the Knut & Alice Wallenberg Foundation, the Linköping Linnaeus Initiative, the Swedish Government Strategic Research Area, and the Ministry of Education, Science, Sports and Culture of Japan.

  2. Fully superconducting rectifiers and fluxpumps

    International Nuclear Information System (INIS)

    Klundert, L.J.M. van de; Kate, H.H.J. ten

    1981-01-01

    Reviewing the basic principles of operation of fluxpumps, mechanical devices such as flux compressors and dynamos are discussed and electrically driven rectifier fluxpumps, with which current levels of over 10 KA can be obtained with high performance, are considered. 132 references. (U.K.)

  3. Feedback loop compensates for rectifier nonlinearity

    Science.gov (United States)

    1966-01-01

    Signal processing circuit with two negative feedback loops rectifies two sinusoidal signals which are 180 degrees out of phase and produces a single full-wave rectified output signal. Each feedback loop incorporates a feedback rectifier to compensate for the nonlinearity of the circuit.

  4. RTD application in low power UHF rectifiers

    International Nuclear Information System (INIS)

    Sinyakin, V Yu; Makeev, M O; Meshkov, S A

    2016-01-01

    In the current work, the problem of UHF RFID passive tag sensitivity increase is considered. Tag sensitivity depends on HF signal rectifier efficiency and antenna-rectifier impedance matching. Possibility of RFID passive tag sensitivity increase up to 10 times by means of RTD use in HF signal rectifier in comparison with tags based on Schottky barrier diode is shown. (paper)

  5. Realistic-contact-induced enhancement of rectifying in carbon-nanotube/graphene-nanoribbon junctions

    International Nuclear Information System (INIS)

    Zhang, Xiang-Hua; Li, Xiao-Fei; Wang, Ling-Ling; Xu, Liang; Luo, Kai-Wu

    2014-01-01

    Carbon-nanotube/graphene-nanoribbon junctions were recently fabricated by the controllable etching of single-walled carbon-nanotubes [Wei et al., Nat. Commun. 4, 1374 (2013)] and their electronic transport properties were studied here. First principles results reveal that the transmission function of the junctions show a heavy dependence on the shape of contacts, but rectifying is an inherent property which is insensitive to the details of contacts. Interestingly, the rectifying ratio is largely enhanced in the junction with a realistic contact and the enhancement is insensitive to the details of contact structures. The stability of rectifying suggests a significant feasibility to manufacture realistic all-carbon rectifiers in nanoelectronics

  6. Experimental investigation of radiative thermal rectifier using vanadium dioxide

    Energy Technology Data Exchange (ETDEWEB)

    Ito, Kota, E-mail: kotaito@mosk.tytlabs.co.jp [Toyota Central Research and Development Labs, Nagakute, Aichi 480-1192 (Japan); Research Center for Advanced Science and Technology (RCAST), The University of Tokyo, Komaba, Meguro-ku, Tokyo 153-8904 (Japan); Nishikawa, Kazutaka; Iizuka, Hideo [Toyota Central Research and Development Labs, Nagakute, Aichi 480-1192 (Japan); Toshiyoshi, Hiroshi [Research Center for Advanced Science and Technology (RCAST), The University of Tokyo, Komaba, Meguro-ku, Tokyo 153-8904 (Japan)

    2014-12-22

    Vanadium dioxide (VO{sub 2}) exhibits a phase-change behavior from the insulating state to the metallic state around 340 K. By using this effect, we experimentally demonstrate a radiative thermal rectifier in the far-field regime with a thin film VO{sub 2} deposited on the silicon wafer. A rectification contrast ratio as large as two is accurately obtained by utilizing a one-dimensional steady-state heat flux measurement system. We develop a theoretical model of the thermal rectifier with optical responses of the materials retrieved from the measured mid-infrared reflection spectra, which is cross-checked with experimentally measured heat flux. Furthermore, we tune the operating temperatures by doping the VO{sub 2} film with tungsten (W). These results open up prospects in the fields of thermal management and thermal information processing.

  7. Common rectifier diodes in temperature measurement applications below 50 K

    International Nuclear Information System (INIS)

    Jaervelae, J; Stenvall, A; Mikkonen, R

    2010-01-01

    In this paper we studied the use of common electronic semiconductor diodes in temperature measurements at cryogenic atmosphere. The motivation for this is the high price of calibrated cryogenic temperature sensors since there are some applications, like quench detection, in which a cheaper and a less accurate sensor would suffice. We measured the forward voltage as a function of temperature, V f (T), of several silicon rectifier diodes to determine the accuracy and interchangeability of the diodes. The experimental results confirmed that V f (T) of common rectifier diodes are similar to cryogenic sensor diodes, but the variability between two samples is much larger. The interchangeability of the diodes proved to be poor if absolute temperatures are to be measured. However for sensing changes in temperature they proved to be adequate and thus can be used to measure e.g. quench propagation or sense quench ignition at multiple locations with cheap price.

  8. Microcrystalline silicon deposition: Process stability and process control

    International Nuclear Information System (INIS)

    Donker, M.N. van den; Kilper, T.; Grunsky, D.; Rech, B.; Houben, L.; Kessels, W.M.M.; Sanden, M.C.M. van de

    2007-01-01

    Applying in situ process diagnostics, we identified several process drifts occurring in the parallel plate plasma deposition of microcrystalline silicon (μc-Si:H). These process drifts are powder formation (visible from diminishing dc-bias and changing spatial emission profile on a time scale of 10 0 s), transient SiH 4 depletion (visible from a decreasing SiH emission intensity on a time scale of 10 2 s), plasma heating (visible from an increasing substrate temperature on a time scale of 10 3 s) and a still puzzling long-term drift (visible from a decreasing SiH emission intensity on a time scale of 10 4 s). The effect of these drifts on the crystalline volume fraction in the deposited films is investigated by selected area electron diffraction and depth-profiled Raman spectroscopy. An example shows how the transient depletion and long-term drift can be prevented by suitable process control. Solar cells deposited using this process control show enhanced performance. Options for process control of plasma heating and powder formation are discussed

  9. A two-phase full-wave superconducting rectifier

    International Nuclear Information System (INIS)

    Ariga, T.; Ishiyama, A.

    1989-01-01

    A two-phase full-wave superconducting rectifier has been developed as a small cryogenic power supply of superconducting magnets for magnetically levitation trains. Those magnets are operated in the persistent current mode. However, small ohmic loss caused at resistive joints and ac loss induced by the vibration of the train cannot be avoided. Therefore, the low-power cryogenic power supply is required to compensate for the reduction in magnet current. The presented superconducting rectifier consists of two identical full-wave rectifiers connected in series. Main components of each rectifier are a troidal shape superconducting set-up transformer and two thermally controlled switches. The test results using a 47.5 mH load magnet at 0.2 Hz and 0.5 Hz operations are described. To estimate the characteristics of the superconducting rectifier, the authors have developed a simulation code. From the experiments and the simulations, the transfer efficiency is examined. Furthermore, the optimal design of thermally controlled switches based on the finite element analysis is also discussed

  10. Position-controlled epitaxial III-V nanowires on silicon

    NARCIS (Netherlands)

    Roest, A.L.; Verheijen, M.A.; Wunnicke, O.; Serafin, S.N.; Wondergem, H.J.; Bakkers, E.P.A.M.

    2006-01-01

    We show the epitaxial integration of III-V semiconductor nanowires with silicon technology. The wires are grown by the VLS mechanism with laser ablation as well as metal-organic vapour phase epitaxy. The hetero-epitaxial growth of the III-V nanowires on silicon was confirmed with x-ray diffraction

  11. Controlling the flow of light with silicon nanostructures

    International Nuclear Information System (INIS)

    Park, W

    2010-01-01

    Silicon is an important material for integrated photonics applications. High refractive index and transparency in the infrared region makes it an ideal platform to implement nanostructures for novel optical devices. We fabricated silicon photonic crystals and experimentally demonstrated negative refraction and self-collimation. We also used heterodyne near-field scanning optical microscope to directly visualize the anomalous wavefronts. When the periodicity is much smaller than wavelength, silicon photonic crystal can be described by the effective medium theory. By engineering effective refractive index with silicon nanorod size, we demonstrated an all-dielectric cloak structure which can hide objects in front of a highly reflecting plane. The work discussed in this review shows the powerful design flexibility and versatility of silicon nanostructures

  12. A DC-Link Modulation Scheme with Phase-Shifted Current Control for Harmonic Cancellations in Multidrive Applications

    DEFF Research Database (Denmark)

    Yang, Yongheng; Davari, Pooya; Zare, Firuz

    2016-01-01

    of a new DC link modulation scheme with a phase-shifted current control enabled by the SCR. The DC-link current modulation scheme is implemented by adding and subtracting specific modulation levels, which makes the total currents drawn from the grid “multi-level”, resulting in an improved current quality......This letter proposes a harmonic mitigation strategy to cancel out current harmonics induced by the front-end rectifiers in multi-drive systems, which consist of diode rectifiers, Silicon-Controlled Rectifiers (SCR), and boost converters in the DC-link. The proposed strategy is a combination...

  13. Enterovaginal or Vesicovaginal Fistula Control Using a Silicone Cup.

    Science.gov (United States)

    Russell, Katie W; Robinson, Ryan E; Mone, Mary C; Scaife, Courtney L

    2016-12-01

    An enterovaginal or vesicovaginal fistula is a complication resulting in vaginal discharge of succus, urine, or stool that can lead to significant complications. For low-volume fistulae, tampons or pads may be used. With high-volume fistulae, frequent product change can be painful and unpredictable in terms of efficacy. The psychologic distress is profound. Surgery may not be an option, making symptom control the priority. We report the use of a reusable menstrual silicone vaginal cup placed to divert and contain drainage. The menstrual cup provided significant symptom relief. Drainage is immediately diverted from tissue, unlike with tampon or pad use, which involves longer contact periods with caustic fluids. A system was created by adapting the end of the cup by adding silastic tubing and an external leg bag to provide long-term drainage control. Improvement in quality of life is of primary importance when dealing with fistula drainage. This simple and inexpensive device should be considered in those cases in which the drainage can be diverted as a viable option, especially in those who are symptomatic and awaiting surgical repair or in those for whom surgery cannot be performed.

  14. Resonant Rectifier ICs for Piezoelectric Energy Harvesting Using Low-Voltage Drop Diode Equivalents.

    Science.gov (United States)

    Din, Amad Ud; Chandrathna, Seneke Chamith; Lee, Jong-Wook

    2017-04-19

    Herein, we present the design technique of a resonant rectifier for piezoelectric (PE) energy harvesting. We propose two diode equivalents to reduce the voltage drop in the rectifier operation, a minuscule-drop-diode equivalent (MDDE) and a low-drop-diode equivalent (LDDE). The diode equivalents are embedded in resonant rectifier integrated circuits (ICs), which use symmetric bias-flip to reduce the power used for charging and discharging the internal capacitance of a PE transducer. The self-startup function is supported by synchronously generating control pulses for the bias-flip from the PE transducer. Two resonant rectifier ICs, using both MDDE and LDDE, are fabricated in a 0.18 μm CMOS process and their performances are characterized under external and self-power conditions. Under the external-power condition, the rectifier using LDDE delivers an output power P OUT of 564 μW and a rectifier output voltage V RECT of 3.36 V with a power transfer efficiency of 68.1%. Under self-power conditions, the rectifier using MDDE delivers a P OUT of 288 μW and a V RECT of 2.4 V with a corresponding efficiency of 78.4%. Using the proposed bias-flip technique, the power extraction capability of the proposed rectifier is 5.9 and 3.0 times higher than that of a conventional full-bridge rectifier.

  15. Resonant Rectifier ICs for Piezoelectric Energy Harvesting Using Low-Voltage Drop Diode Equivalents

    Science.gov (United States)

    Din, Amad Ud; Chandrathna, Seneke Chamith; Lee, Jong-Wook

    2017-01-01

    Herein, we present the design technique of a resonant rectifier for piezoelectric (PE) energy harvesting. We propose two diode equivalents to reduce the voltage drop in the rectifier operation, a minuscule-drop-diode equivalent (MDDE) and a low-drop-diode equivalent (LDDE). The diode equivalents are embedded in resonant rectifier integrated circuits (ICs), which use symmetric bias-flip to reduce the power used for charging and discharging the internal capacitance of a PE transducer. The self-startup function is supported by synchronously generating control pulses for the bias-flip from the PE transducer. Two resonant rectifier ICs, using both MDDE and LDDE, are fabricated in a 0.18 μm CMOS process and their performances are characterized under external and self-power conditions. Under the external-power condition, the rectifier using LDDE delivers an output power POUT of 564 μW and a rectifier output voltage VRECT of 3.36 V with a power transfer efficiency of 68.1%. Under self-power conditions, the rectifier using MDDE delivers a POUT of 288 μW and a VRECT of 2.4 V with a corresponding efficiency of 78.4%. Using the proposed bias-flip technique, the power extraction capability of the proposed rectifier is 5.9 and 3.0 times higher than that of a conventional full-bridge rectifier. PMID:28422085

  16. Position-controlled epitaxial III-V nanowires on silicon

    Energy Technology Data Exchange (ETDEWEB)

    Roest, Aarnoud L; Verheijen, Marcel A; Wunnicke, Olaf; Serafin, Stacey; Wondergem, Harry; Bakkers, Erik P A M [Philips Research Laboratories, Professor Holstlaan 4, 5656 AA Eindhoven (Netherlands); Kavli Institute of NanoScience, Delft University of Technology, PO Box 5046, 2600 GA Delft (Netherlands)

    2006-06-14

    We show the epitaxial integration of III-V semiconductor nanowires with silicon technology. The wires are grown by the VLS mechanism with laser ablation as well as metal-organic vapour phase epitaxy. The hetero-epitaxial growth of the III-V nanowires on silicon was confirmed with x-ray diffraction pole figures and cross-sectional transmission electron microscopy. We show preliminary results of two-terminal electrical measurements of III-V nanowires grown on silicon. E-beam lithography was used to predefine the position of the nanowires.

  17. Position-controlled epitaxial III-V nanowires on silicon

    International Nuclear Information System (INIS)

    Roest, Aarnoud L; Verheijen, Marcel A; Wunnicke, Olaf; Serafin, Stacey; Wondergem, Harry; Bakkers, Erik P A M

    2006-01-01

    We show the epitaxial integration of III-V semiconductor nanowires with silicon technology. The wires are grown by the VLS mechanism with laser ablation as well as metal-organic vapour phase epitaxy. The hetero-epitaxial growth of the III-V nanowires on silicon was confirmed with x-ray diffraction pole figures and cross-sectional transmission electron microscopy. We show preliminary results of two-terminal electrical measurements of III-V nanowires grown on silicon. E-beam lithography was used to predefine the position of the nanowires

  18. A Voltage Modulated DPC Approach for Three-Phase PWM Rectifier

    DEFF Research Database (Denmark)

    Gui, Yonghao; Li, Mingshen; Lu, Jinghang

    2018-01-01

    In this paper, a voltage modulated direct power control for three-phase pulse-width modulated rectifier is proposed. With the suggested method, the differential equations describing the rectifier dynamics are changing from a linear time-varying system into a linear time-invariant one. In this way...

  19. Three Phase Six-Switch PWM Buck Rectifier with Power Factor Improvement

    DEFF Research Database (Denmark)

    Zafar Ullah Khan, M; Mohsin Naveed, M.; Hussain, Dil Muhammad Akbar

    2013-01-01

    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[1] is presented which operates at nearly unity power factor and provides...

  20. A low cost rapid prototype platform for a three phase PFC rectifier application

    DEFF Research Database (Denmark)

    Haase, Frerk; Kouchaki, Alireza; Nymand, Morten

    2015-01-01

    In this paper the design and development of a low cost rapid prototype platform for a Three Phase PFC rectifier application is presented. The active rectifier consists of a SiC-MOSFET based PWM converter and a low cost rapid prototype platform for simulating and implementing the digital control...

  1. Density control of dodecamanganese clusters anchored on silicon(100).

    Science.gov (United States)

    Condorelli, Guglielmo G; Motta, Alessandro; Favazza, Maria; Nativo, Paola; Fragalà, Ignazio L; Gatteschi, Dante

    2006-04-24

    A synthetic strategy to control the density of Mn12 clusters anchored on silicon(100) was investigated. Diluted monolayers suitable for Mn12 anchoring were prepared by Si-grafting mixtures of the methyl 10-undecylenoate precursor ligand with 1-decene spectator spacers. Different ratios of these mixtures were tested. The grafted surfaces were hydrolyzed to reveal the carboxylic groups available for the subsequent exchange with the [Mn12O12(OAc)16(H2O)4]4 H2O2 AcOH cluster. Modified surfaces were analyzed by attenuated total reflection (ATR)-FTIR spectroscopy, X-ray photoemission spectroscopy (XPS), and AFM imaging. Results of XPS and ATR-FTIR spectroscopy show that the surface mole ratio between grafted ester and decene is higher than in the source solution. The surface density of the Mn12 cluster is, in turn, strictly proportional to the ester mole fraction. Well-resolved and isolated clusters were observed by AFM, using a diluted ester/decene 1:1 solution.

  2. Quantum Control and Entanglement of Spins in Silicon Carbide

    Science.gov (United States)

    Klimov, Paul

    Over the past several decades silicon carbide (SiC) has matured into a versatile material platform for high-power electronics and optoelectronic and micromechanical devices. Recent advances have also established SiC as a promising host for quantum technologies based on the spin of intrinsic defects, with the potential of leveraging existing device fabrication protocols alongside solid-state quantum control. Among these defects are the divacancies and related color centers, which have ground-state electron-spin triplets with coherence times as long as one millisecond and built-in optical interfaces operating near the telecommunication wavelengths. This rapidly developing field has prompted research into the SiC material host to understand how defect-bound electron spins interact with their surrounding nuclear spin bath. Although nuclear spins are a major source of decoherence in color-center spin systems, they are also a valuable resource since they can have coherence times that are orders of magnitude longer than electron spins. In this talk I will discuss our recent efforts to interface defect-bound electron spins in SiC with the nuclear spins of naturally occurring 29Si and 13C isotopic defects. I will discuss how the hyperfine interaction can be used to strongly initialize them, to coherently control them, to read them out, and to produce genuine electron-nuclear ensemble entanglement, all at ambient conditions. These demonstrations motivate further research into spins in SiC for prospective quantum technologies. In collaboration with A. Falk, D. Christle, K. Miao, H. Seo, V. Ivady, A. Gali, G. Galli, and D. D. Awschalom. This research was supported by the AFOSR, the NSF DMR-1306300, and the NSF Materials Research Science and Engineering Center.

  3. Measurement of Phase Dependent Impedance for 3-phase Diode Rectifier

    DEFF Research Database (Denmark)

    Kwon, Jun Bum; Wang, Xiongfei; Bak, Claus Leth

    2016-01-01

    This paper presents a new method to measure the phase dependent impedance from an experimental set up. Though most of power electronics based system is gradually migrating to IGBT based voltage source converter due to their controllability, the rectifier composed of diode or thyristor components...

  4. Laserlike Vibrational Instability in Rectifying Molecular Conductors

    DEFF Research Database (Denmark)

    Lu, Jing Tao; Hedegård, Per; Brandbyge, Mads

    2011-01-01

    We study the damping of molecular vibrations due to electron-hole pair excitations in donor-acceptor (D-A) type molecular rectifiers. At finite voltage additional nonequilibrium electron-hole pair excitations involving both electrodes become possible, and contribute to the stimulated emission....... We investigate the effect in realistic molecular rectifier structures using first-principles calculations....

  5. High current and high power superconducting rectifiers

    International Nuclear Information System (INIS)

    Kate, H.H.J. ten; Bunk, P.B.; Klundert, L.J.M. van de; Britton, R.B.

    1981-01-01

    Results on three experimental superconducting rectifiers are reported. Two of them are 1 kA low frequency flux pumps, one thermally and magnetically switched. The third is a low-current high-frequency magnetically switched rectifier which can use the mains directly. (author)

  6. Extremal vectors and rectifiability | Enflo | Quaestiones Mathematicae

    African Journals Online (AJOL)

    Extremal vectors and rectifiability. ... The concept of extremal vectors of a linear operator with a dense range but not onto on a Hilbert space was introduced by P. Enflo in 1996 as a new approach to study invariant subspaces ... We show that in general curves that map numbers to backward minimal vectors are not rectifiable.

  7. Peak Power Control with an Energy Management System

    Science.gov (United States)

    2013-03-01

    EMS. .....................18  Figure 17.  Circuit schematic implemented in the Simulink model. ..................................18  Figure 18.  The...21  Figure 20.  The non-critical load block implementation ...Modulation SCR Silicon Controller Rectifier SDC Student Design Center TTL Transistor Transistor Logic USB Universal Serial Bus VHDL VHSIC Hardware

  8. Spatial control of direct chemical vapor deposition of graphene on silicon dioxide by directional copper dewetting

    NARCIS (Netherlands)

    van den Beld, Wesley Theodorus Eduardus; van den Berg, Albert; Eijkel, Jan C.T.

    2016-01-01

    In this paper we present a method for the spatial control of direct graphene synthesis onto silicon dioxide by controlled dewetting. The dewetting process is controlled through a combination of using a grooved substrate and conducting copper deposition at an angle. The substrate is then treated

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

    Science.gov (United States)

    Wang, Chenlei

    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

  10. Rectifier transformer saturation on commutation failure

    International Nuclear Information System (INIS)

    Lu, E.; Bronner, G.

    1989-01-01

    The rectifier transformer's service differs from the power transformer's service because of the rectifier load. Under certain fault conditions, such as a commutation failure, d.c. magnetization may be introduced into the rectifier transformer cores, resulting in possible saturation of the magnetic circuit, thus in degradation of the performance of the transformer. It is the purpose of this paper to present an approach for evaluating the electromagnetic transient process under such a fault condition. The studies were made on the operating 1000MVA converter system at the Princeton Plasma Physics Laboratory

  11. Multivariate data analysis of process control data from neutron transmutation doping of silicon

    DEFF Research Database (Denmark)

    Heydorn, K.; Hegaard, N.

    1994-01-01

    Final resistivities obtained by neutron transmutation doping (NTD) of silicon can be measured only after an annealing process has been carried out at the manufacturer's plant. The reactor centre carrying out the neutron doping process by irradiation under selected conditions must control the proc......Final resistivities obtained by neutron transmutation doping (NTD) of silicon can be measured only after an annealing process has been carried out at the manufacturer's plant. The reactor centre carrying out the neutron doping process by irradiation under selected conditions must control...

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

    International Nuclear Information System (INIS)

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

    2014-01-01

    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 µL 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. (paper)

  13. A boron nitride nanotube peapod thermal rectifier

    International Nuclear Information System (INIS)

    Loh, G. C.; Baillargeat, D.

    2014-01-01

    The precise guidance of heat from one specific location to another is paramount in many industrial and commercial applications, including thermal management and thermoelectric generation. One of the cardinal requirements is a preferential conduction of thermal energy, also known as thermal rectification, in the materials. This study introduces a novel nanomaterial for rectifying heat—the boron nitride nanotube peapod thermal rectifier. Classical non-equilibrium molecular dynamics simulations are performed on this nanomaterial, and interestingly, the strength of the rectification phenomenon is dissimilar at different operating temperatures. This is due to the contingence of the thermal flux on the conductance at the localized region around the scatterer, which varies with temperature. The rectification performance of the peapod rectifier is inherently dependent on its asymmetry. Last but not least, the favourable rectifying direction in the nanomaterial is established.

  14. A boron nitride nanotube peapod thermal rectifier

    Energy Technology Data Exchange (ETDEWEB)

    Loh, G. C., E-mail: jgloh@mtu.edu [Department of Physics, Michigan Technological University, Houghton, Michigan 49931 (United States); Institute of High Performance Computing, 1 Fusionopolis Way, #16-16 Connexis, Singapore 138632 (Singapore); Baillargeat, D. [CNRS-International-NTU-Thales Research Alliance (CINTRA), 50 Nanyang Drive, Singapore 637553 (Singapore)

    2014-06-28

    The precise guidance of heat from one specific location to another is paramount in many industrial and commercial applications, including thermal management and thermoelectric generation. One of the cardinal requirements is a preferential conduction of thermal energy, also known as thermal rectification, in the materials. This study introduces a novel nanomaterial for rectifying heat—the boron nitride nanotube peapod thermal rectifier. Classical non-equilibrium molecular dynamics simulations are performed on this nanomaterial, and interestingly, the strength of the rectification phenomenon is dissimilar at different operating temperatures. This is due to the contingence of the thermal flux on the conductance at the localized region around the scatterer, which varies with temperature. The rectification performance of the peapod rectifier is inherently dependent on its asymmetry. Last but not least, the favourable rectifying direction in the nanomaterial is established.

  15. A 62GHz inductor-peaked rectifier with 7% efficiency

    NARCIS (Netherlands)

    Gao, H.; Matters - Kammerer, M.; Milosevic, D.; Roermund, van A.H.M.; Baltus, P.G.M.

    2013-01-01

    This paper presents the first 62 GHz fully onchip RF-DC rectifier in 65nm CMOS technology. The rectifier is the bottleneck in realizing on-chip wireless power receivers. In this paper, efficiency problems of the mm-wave rectifier are discussed and the inductor-peaked rectifier structure is proposed

  16. pH-controlled silicon nanowires fluorescence switch

    International Nuclear Information System (INIS)

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

    2010-01-01

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

  17. Wind Solar Hybrid System Rectifier Stage Topology Simulation

    OpenAIRE

    Anup M. Gakare; Subhash Kamdi

    2014-01-01

    This paper presents power-control strategies of a grid-connected hybrid generation system with versatile power transfer. The hybrid system allows maximum utilization of freely available renewable sources like wind and photovoltaic energies. This paper presents a new system configuration of the multi input rectifier stage for a hybrid wind and photovoltaic energy system. This configuration allows the two sources to supply the load simultaneously depending on the availability of...

  18. Performance improvement of three phase rectifier by employing electronic smoothing inductor

    DEFF Research Database (Denmark)

    Singh, Yash Veer; Rasmussen, Peter Omand; Andersen, Torben O.

    2014-01-01

    density of the rectifier. In case of an inverter connected to the output of the rectifier, peak to peak voltage ripples to the front end of the inverter reduces significantly by the ESI, and it increases lifetime of the capacitor connected to the dc link and reduces the voltage stress of the active power...... semiconductors of the inverter. In this paper, an average model of the ESI and its control schemes are presented....

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

    DEFF Research Database (Denmark)

    Sun, Jie; Lindvall, Niclas; Cole, Matthew T.

    2012-01-01

    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...

  20. The silicon sensor for the compact muon solenoid tracker. Control of the fabrication process

    International Nuclear Information System (INIS)

    Manolescu, Florentina; Mihul, Alexandru; Macchiolo, Anna

    2005-01-01

    The Compact Muon Solenoid (CMS) is one of the experiments at the Large Hadron Collider (LHC) under construction at CERN. The inner tracking system of this experiment consists of the world largest Silicon Strip Tracker (SST). In total, 24,244 silicon sensors are implemented covering an area of 206 m 2 . To construct this large system and to ensure its functionality for the full lifetime of ten years under the hard LHC condition, a detailed quality assurance program has been developed. This paper describes the strategy of the Process Qualification Control to monitor the stability of the fabrication process throughout the production phase and the results obtained are shown. (authors)

  1. Control of back surface reflectance from aluminum alloyed contacts on silicon solar cells

    Energy Technology Data Exchange (ETDEWEB)

    Cudzinovic, M.; Sopori, B. [National Renewable Energy Lab., Golden, CO (United States)

    1996-05-01

    A process for forming highly reflective aluminum back contacts with low contact resistance to silicon solar cells is described. By controlling the process conditions, it is possible to vary the silicon/aluminum interface from a specular to a diffuse reflector while maintaining a high interface reflectance. The specular interface is found to be a uniform silicon/aluminum alloy layer a few angstroms thick that has epitaxially regrown on the silicon. The diffuse interface consists of randomly distributed (111) pyramids produced by crystallographic out-diffusion of the bulk silicon. The light trapping ability of the diffuse contact is found to be close to the theoretical limit. Both types of contacts are found to have specific contact resistivities of 10{sup {minus}5} {Omega}-cm{sup 2}. The process for forming the contacts involves illuminating the devices with tungsten halogen lamps. The process is rapid (under 100 s) and low temperature (peak temperature < 580{degrees}C), making it favorable for commercial solar cell fabrication.

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

    Science.gov (United States)

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

    2018-04-16

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

  3. Controlling the Nanoscale Patterning of AuNPs on Silicon Surfaces

    Directory of Open Access Journals (Sweden)

    Chris J. Allender

    2013-03-01

    Full Text Available This study evaluates the effectiveness of vapour-phase deposition for creating sub-monolayer coverage of aminopropyl triethoxysilane (APTES on silicon in order to exert control over subsequent gold nanoparticle deposition. Surface coverage was evaluated indirectly by observing the extent to which gold nanoparticles (AuNPs deposited onto the modified silicon surface. By varying the distance of the silicon wafer from the APTES source and concentration of APTES in the evaporating media, control over subsequent gold nanoparticle deposition was achievable to an extent. Fine control over AuNP deposition (AuNPs/μm2 however, was best achieved by adjusting the ionic concentration of the AuNP-depositing solution. Furthermore it was demonstrated that although APTES was fully removed from the silicon surface following four hours incubation in water, the gold nanoparticle-amino surface complex was stable under the same conditions. Atomic force microscopy (AFM and X-ray photoelectron spectroscopy (XPS were used to study these affects.

  4. Control growth of silicon nanocolumns' epitaxy on silicon nanowires

    Energy Technology Data Exchange (ETDEWEB)

    Chong, Su Kong, E-mail: sukong1985@yahoo.com.my [University of Malaya, Low Dimensional Materials Research Centre, Department of Physics (Malaysia); Dee, Chang Fu [Universiti Kebangsaan Malaysia (UKM), Institute of Microengineering and Nanoelectronics (IMEN) (Malaysia); Yahya, Noorhana [Universiti Teknologi PETRONAS, Faculty of Science and Information Technology (Malaysia); Rahman, Saadah Abdul [University of Malaya, Low Dimensional Materials Research Centre, Department of Physics (Malaysia)

    2013-04-15

    The epitaxial growth of Si nanocolumns on Si nanowires was studied using hot-wire chemical vapor deposition. A single-crystalline and surface oxide-free Si nanowire core (core radius {approx}21 {+-} 5 nm) induced by indium crystal seed was used as a substance for the vapor phase epitaxial growth. The growth process is initiated by sidewall facets, which then nucleate upon certain thickness to form Si islands and further grow to form nanocolumns. The Si nanocolumns with diameter of 10-20 nm and aspect ratio up to 10 can be epitaxially grown on the surface of nanowires. The results showed that the radial growth rate of the Si nanocolumns remains constant with the increase of deposition time. Meanwhile, the radial growth rates are controllable by manipulating the hydrogen to silane gas flow rate ratio. The optical antireflection properties of the Si nanocolumns' decorated SiNW arrays are discussed in the text.

  5. Development of fluorocarbon evaporative cooling recirculators and controls for the ATLAS inner silicon tracker

    CERN Document Server

    Bayer, C; Bonneau, P; Bosteels, Michel; Burckhart, H J; Cragg, D; English, R; Hallewell, G D; Hallgren, Björn I; Ilie, S; Kersten, S; Kind, P; Langedrag, K; Lindsay, S; Merkel, M; Stapnes, Steinar; Thadome, J; Vacek, V

    2000-01-01

    We report on the development of evaporative fluorocarbon cooling recirculators and their control systems for the ATLAS inner silicon tracker. We have developed a prototype circulator using a dry, hermetic compressor with C/sub 3/F/sup 8/ refrigerant, and have prototyped the remote-control analog pneumatic links for the regulation of coolant mass flows and operating temperatures that will be necessary in the magnetic field and radiation environment around ATLAS. pressure and flow measurement and control use 150+ channels of standard ATLAS LMB ("Local Monitor Board") DAQ and DACs on a multi-drop CAN network administered through a BridgeVIEW user interface. A hardwired thermal interlock system has been developed to cut power to individual silicon modules should their temperatures exceed safe values. Highly satisfactory performance of the circulator under steady state, partial-load and transient conditions was seen, with proportional fluid flow tuned to varying circuit power. Future developments, including a 6 kW...

  6. Structural Optimization of Non-Newtonian Rectifiers

    DEFF Research Database (Denmark)

    Jensen, Kristian Ejlebjærg; Okkels, Fridolin

    When the size of fluidic devices is scaled down, inertial effects start to vanish such that the governing equation becomes linear. Some microfluidic devices rely on the non-linear term related to the inertia of the fluid, and one example is fluid rectifiers (diodes) e.g. related to some micropumps....... These rectifiers rely on the device geometry for their working mechanism, but on further downscaling the inertial effect vanishes and the governing equation starts to show symmetry properties. These symmetry properties reduce the geometry influence to the point where fluid rectifiers cease to function....... In this context it is natural to look for other sources of non-linearity and one possibility is to introduce a non-Newtonian working fluid. Non-Newtonian properties are due to stretching of large particles/molecules in the fluid and this is commonly seen for biological samples in “lab-on-a-chip” systems...

  7. Pharmacological Conversion of a Cardiac Inward Rectifier into an Outward Rectifier Potassium Channel.

    Science.gov (United States)

    Moreno-Galindo, Eloy G; Sanchez-Chapula, Jose A; Tristani-Firouzi, Martin; Navarro-Polanco, Ricardo A

    2016-09-01

    Potassium (K(+)) channels are crucial for determining the shape, duration, and frequency of action-potential firing in excitable cells. Broadly speaking, K(+) channels can be classified based on whether their macroscopic current outwardly or inwardly rectifies, whereby rectification refers to a change in conductance with voltage. Outwardly rectifying K(+) channels conduct greater current at depolarized membrane potentials, whereas inward rectifier channels conduct greater current at hyperpolarized membrane potentials. Under most circumstances, outward currents through inwardly rectifying K(+) channels are reduced at more depolarized potentials. However, the acetylcholine-gated K(+) channel (KACh) conducts current that inwardly rectifies when activated by some ligands (such as acetylcholine), and yet conducts current that outwardly rectifies when activated by other ligands (for example, pilocarpine and choline). The perplexing and paradoxical behavior of KACh channels is due to the intrinsic voltage sensitivity of the receptor that activates KACh channels, the M2 muscarinic receptor (M2R). Emerging evidence reveals that the affinity of M2R for distinct ligands varies in a voltage-dependent and ligand-specific manner. These intrinsic receptor properties determine whether current conducted by KACh channels inwardly or outwardly rectifies. This review summarizes the most recent concepts regarding the intrinsic voltage sensitivity of muscarinic receptors and the consequences of this intriguing behavior on cardiac physiology and pharmacology of KACh channels. Copyright © 2016 by The American Society for Pharmacology and Experimental Therapeutics.

  8. Process controls for radiation hardened aluminum gate bulk silicon CMOS

    International Nuclear Information System (INIS)

    Gregory, B.L.

    1975-01-01

    Optimized dry oxides have recently yielded notable improvements in CMOS radiation-hardness. By following the proper procedures and recipes, it is now possible to produce devices which will function satisfactorily after exposure to a total ionizing dose in excess of 10 6 RADS (Si). This paper is concerned with the controls required on processing parameters once the optimized process is defined. In this process, the pre-irradiation electrical parameters must be closely controlled to insure that devices will function after irradiation. In particular, the specifications on n- and p-channel threshold voltages require tight control of fixed oxide charge, surface-state density, oxide thickness, and substrate and p-well surface concentrations. In order to achieve the above level of radiation hardness, certain processing procedures and parameters must also be closely controlled. Higher levels of cleanliness are required in the hardened process than are commonly required for commercial CMOS since, for hardened dry oxides, no impurity gettering can be employed during or after oxidation. Without such gettering, an unclean oxide is unacceptable due to bias-temperature instability. Correct pre-oxidation cleaning, residual surface damage removal, proper oxidation and annealing temperatures and times, and the correct metal sintering cycle are all important in determining device hardness. In a reproducible, hardened process, each of these processing steps must be closely controlled. (U.S.)

  9. Process control of high rate microcrystalline silicon based solar cell deposition by optical emission spectroscopy

    International Nuclear Information System (INIS)

    Kilper, T.; Donker, M.N. van den; Carius, R.; Rech, B.; Braeuer, G.; Repmann, T.

    2008-01-01

    Silicon thin-film solar cells based on microcrystalline silicon (μc-Si:H) were prepared in a 30 x 30 cm 2 plasma-enhanced chemical vapor deposition reactor using 13.56 or 40.68 MHz plasma excitation frequency. Plasma emission was recorded by optical emission spectroscopy during μc-Si:H absorber layer deposition at deposition rates between 0.5 and 2.5 nm/s. The time course of SiH * and H β emission indicated strong drifts in the process conditions particularly at low total gas flows. By actively controlling the SiH 4 gas flow, the observed process drifts were successfully suppressed resulting in a more homogeneous i-layer crystallinity along the growth direction. In a deposition regime with efficient usage of the process gas, the μc-Si:H solar cell efficiency was enhanced from 7.9 % up to 8.8 % by applying process control

  10. Controlling magnetic and electric dipole modes in hollow silicon nanocylinders.

    Science.gov (United States)

    van de Haar, Marie Anne; van de Groep, Jorik; Brenny, Benjamin J M; Polman, Albert

    2016-02-08

    We propose a dielectric nanoresonator geometry consisting of hollow dielectric nanocylinders which support geometrical resonances. We fabricate such hollow Si particles with an outer diameter of 108-251 nm on a Si substrate, and determine their resonant modes with cathodo-luminescence (CL) spectroscopy and optical dark-field (DF) scattering measurements. The scattering behavior is numerically investigated in a systematic fashion as a function of wavelength and particle geometry. We find that the additional design parameter as a result of the introduction of a center gap can be used to control the relative spectral spacing of the resonant modes, which will enable additional control over the angular radiation pattern of the scatterers. Furthermore, the gap offers direct access to the enhanced magnetic dipole modal field in the center of the particle.

  11. Genetic Algorithm-Based Design of the Active Damping for an LCL-Filter Three-Phase Active Rectifier

    DEFF Research Database (Denmark)

    Liserre, Marco; Aquila, Antonio Dell; Blaabjerg, Frede

    2004-01-01

    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 order to overcome them, a damping resistor can be inserted, at the price of a reduction of efficiency. The use of active damping by means of control may seem attractive, but it is often limited by the use...

  12. Sensitivity analysis of an LCL-filter-based three-phase active rectifier via a virtual circuit approach

    DEFF Research Database (Denmark)

    Blaabjerg, Frede; Chiarantoni, Ernesto; Aquila, Antonio Dell’

    2004-01-01

    Three-phase active rectifiers based on the voltage source converter topology can successfully replace traditional thyristor based rectifiers or diode bridge plus chopper in interfacing dc-systems to the grid. However, if the application in which they are employed has a high safety issue......, to the grid side stiffness and to the parameters of the controller has never been detailed considered. In this paper the experimental results of an LCL-filter-based three-phase active rectifier are analysed with the circuit theory approach. A ?virtual circuit? is synthesized in role of the digital controller...

  13. Harmonic Distortion of Rectifier Topologies for Adjustable Speed Drives

    DEFF Research Database (Denmark)

    Hansen, Steffan

    This thesis deals with the harmonic distortion of the diode rectifier and a number of alternative rectifier topologies for adjustable speed drives. The main intention of this thesis is to provide models and tools that allow easy prediction of the harmonic distortion of ASD’s in a given system...... rectifier are presented. The first level is an ideal model where the diode rectifier basically is treated as an independent (harmonic) current source. The second level is an empirical model, where simulated (or measured) values of the harmonic currents of the diode rectifier for different parameters......-angle of the individual harmonic currents of different diode rectifier types is analyzed. Four selected rectifier topologies with a high input power factor are presented. It is shown that using ac- or dc-coils is a very simple and efficient method to reduce the harmonic currents compared to the basic diode rectifier...

  14. Fabrication of disposable topographic silicon oxide from sawtoothed patterns: control of arrays of gold nanoparticles.

    Science.gov (United States)

    Cho, Heesook; Yoo, Hana; Park, Soojin

    2010-05-18

    Disposable topographic silicon oxide patterns were fabricated from polymeric replicas of sawtoothed glass surfaces, spin-coating of poly(dimethylsiloxane) (PDMS) thin films, and thermal annealing at certain temperature and followed by oxygen plasma treatment of the thin PDMS layer. A simple imprinting process was used to fabricate the replicated PDMS and PS patterns from sawtoothed glass surfaces. Next, thin layers of PDMS films having different thicknesses were spin-coated onto the sawtoothed PS surfaces and annealed at 60 degrees C to be drawn the PDMS into the valley of the sawtoothed PS surfaces, followed by oxygen plasma treatment to fabricate topographic silicon oxide patterns. By control of the thickness of PDMS layers, silicon oxide patterns having various line widths were fabricated. The silicon oxide topographic patterns were used to direct the self-assembly of polystyrene-block-poly(2-vinylpyridine) (PS-b-P2VP) block copolymer thin films via solvent annealing process. A highly ordered PS-b-P2VP micellar structure was used to let gold precursor complex with P2VP chains, and followed by oxygen plasma treatment. When the PS-b-P2VP thin films containing gold salts were exposed to oxygen plasma environments, gold salts were reduced to pure gold nanoparticles without changing high degree of lateral order, while polymers were completely degraded. As the width of trough and crest in topographic patterns increases, the number of gold arrays and size of gold nanoparticles are tuned. In the final step, the silicon oxide topographic patterns were selectively removed by wet etching process without changing the arrays of gold nanoparticles.

  15. Deposition of controllable preferred orientation silicon films on glass by inductively coupled plasma chemical vapor deposition

    International Nuclear Information System (INIS)

    Li Junshuai; Wang Jinxiao; Yin Min; Gao Pingqi; He Deyan; Chen Qiang; Li Yali; Shirai, Hajime

    2008-01-01

    An inductively coupled plasma (ICP) system with the adjustable distance between the inductance coil and substrates was designed to effectively utilize the spatial confinement of ICP discharge, and then control the gas-phase transport process. The effects of the gas phase processes on the crystallinity and preferred orientation of silicon films deposited on glass were systematically investigated. The investigation was conducted in the ICP-chemical vapor deposition process with the precursor gas of a SiH 4 /H 2 mixture at a substrate temperature of 350 deg. Highly crystallized silicon films with different preferred orientations, (111) or (220), could be selectively deposited by adjusting the SiH 4 dilution ratio [R=[SiH 4 ]/([SiH 4 ]+[H 2 ])] or total working pressure. When the total working pressure is 20 Pa, the crystallinity of the silicon films increases with the increase of the SiH 4 dilution ratio, while the preferred orientation was changed from (111) to (220). In the case of the fixed SiH 4 dilution (10%), the silicon film with I (220) /I (111) of about 3.5 and Raman crystalline fraction of about 89.6% has been deposited at 29.7 nm/min when the total working pressure was increased to 40 Pa. At the fixed SiH 4 partial pressure of 2 Pa, the film crystallinity decreases and the preferred orientation is always (111) with increasing the H 2 partial pressure from 18 to 58 Pa. Atomic force microscope reveals that the film deposited at a relatively high H 2 partial pressure has a very rough surface caused by the devastating etching of H atoms to the silicon network

  16. Minimum component high frequency current mode rectifier | Sampe ...

    African Journals Online (AJOL)

    In this paper a current mode full wave rectifier circuit is proposed. The current mode rectifier circuit is implemented utilizing a floating current source (FCS) as an active element. The minimum component full wave rectifier utilizes only a single floating current source, two diodes and two grounded resistors. The extremely ...

  17. 46 CFR 183.360 - Semiconductor rectifier systems.

    Science.gov (United States)

    2010-10-01

    ... 46 Shipping 7 2010-10-01 2010-10-01 false Semiconductor rectifier systems. 183.360 Section 183.360... TONS) ELECTRICAL INSTALLATION Power Sources and Distribution Systems § 183.360 Semiconductor rectifier systems. (a) Each semiconductor rectifier system must have an adequate heat removal system that prevents...

  18. 46 CFR 129.360 - Semiconductor-rectifier systems.

    Science.gov (United States)

    2010-10-01

    ... 46 Shipping 4 2010-10-01 2010-10-01 false Semiconductor-rectifier systems. 129.360 Section 129.360... INSTALLATIONS Power Sources and Distribution Systems § 129.360 Semiconductor-rectifier systems. (a) Each semiconductor-rectifier system must have an adequate heat-removal system to prevent overheating. (b) If a...

  19. 46 CFR 120.360 - Semiconductor rectifier systems.

    Science.gov (United States)

    2010-10-01

    ... 46 Shipping 4 2010-10-01 2010-10-01 false Semiconductor rectifier systems. 120.360 Section 120.360... INSTALLATION Power Sources and Distribution Systems § 120.360 Semiconductor rectifier systems. (a) Each semiconductor rectifier system must have an adequate heat removal system that prevents overheating. (b) Where a...

  20. High Power Factor Hybrid Rectifier | Odeh | Nigerian Journal of ...

    African Journals Online (AJOL)

    This paper presents the analysis of a new single-phase hybrid rectifier with high power factor (PF) and low harmonic distortion current. The proposed rectifier structure is composed of an ordinary single-phase diode rectifier with parallel connection of a switched converter. It is outlined that the switched converter is capable of ...

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

    KAUST Repository

    Mula, Guido

    2014-07-04

    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.

  2. Control of single-electron charging of metallic nanoparticles onto amorphous silicon surface.

    Science.gov (United States)

    Weis, Martin; Gmucová, Katarína; Nádazdy, Vojtech; Capek, Ignác; Satka, Alexander; Kopáni, Martin; Cirák, Július; Majková, Eva

    2008-11-01

    Sequential single-electron charging of iron oxide nanoparticles encapsulated in oleic acid/oleyl amine envelope and deposited by the Langmuir-Blodgett technique onto Pt electrode covered with undoped hydrogenated amorphous silicon film is reported. Single-electron charging (so-called quantized double-layer charging) of nanoparticles is detected by cyclic voltammetry as current peaks and the charging effect can be switched on/off by the electric field in the surface region induced by the excess of negative/positive charged defect states in the amorphous silicon layer. The particular charge states in amorphous silicon are created by the simultaneous application of a suitable bias voltage and illumination before the measurement. The influence of charged states on the electric field in the surface region is evaluated by the finite element method. The single-electron charging is analyzed by the standard quantized double layer model as well as two weak-link junctions model. Both approaches are in accordance with experiment and confirm single-electron charging by tunnelling process at room temperature. This experiment illustrates the possibility of the creation of a voltage-controlled capacitor for nanotechnology.

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

    Science.gov (United States)

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

    2013-03-01

    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.

  4. LHCb: The LHCb Silicon Tracker - Control system specific tools and challenges

    CERN Multimedia

    Saornil Gamarra, S

    2013-01-01

    The experiment control system of the LHCb experiment is continuously evolving and improving. The guidelines and structure initially defined are kept, and more common tools are made available to all sub-detectors. Although the main system control is mostly integrated and actions are executed in common for the whole LHCb experiment, there is some degree of freedom for each sub-system to implement the control system using these tools or by creating new ones. The implementation of the LHCb Silicon Tracker control system was extremely disorganized and with little documentation. This was due to either lack of time and manpower, and/or to limited experience and specifications. Despite this, the Silicon Tracker control system has behaved well during the first LHC run. It has continuously evolved since the start of operation and been adapted to the needs of operators with very different degrees of expertise. However, improvements and corrections have been made on a best effort basis due to time constraints placed by t...

  5. Understanding and controlling the step bunching instability in aqueous silicon etching

    Science.gov (United States)

    Bao, Hailing

    Chemical etching of silicon has been widely used for more than half a century in the semiconductor industry. It not only forms the basis for current wafer cleaning processes, it also serves as a powerful tool to create a variety of surface morphologies for different applications. Its potential for controlling surface morphology at the atomic scale over micron-size regions is especially appealing. In spite of its wide usage, the chemistry of silicon etching is poorly understood. Many seemingly simple but fundamental questions have not been answered. As a result, the development of new etchants and new etching protocols are based on expensive and tedious trial-and-error experiments. A better understanding of the etching mechanism would direct the rational formulation of new etchants that produce controlled etch morphologies. Particularly, micron-scale step bunches spontaneously develop on the vicinal Si(111) surface etched in KOH or other anisotropic aqueous etchants. The ability to control the size, orientation, density and regularity of these surface features would greatly improve the performance of microelectromechanical devices. This study is directed towards understanding the chemistry and step bunching instability in aqueous anisotropic etching of silicon through a combination of experimental techniques and theoretical simulations. To reveal the cause of step-bunching instability, kinetic Monte Carlo simulations were constructed based on an atomistic model of the silicon lattice and a modified kinematic wave theory. The simulations showed that inhomogeneity was the origin of step-bunching, which was confirmed through STM studies of etch morphologies created under controlled flow conditions. To quantify the size of the inhomogeneities in different etchants and to clarify their effects, a five-parallel-trench pattern was fabricated. This pattern used a nitride mask to protect most regions of the wafer; five evenly spaced etch windows were opened to the Si(110

  6. Site-Controlled Growth of Monolithic InGaAs/InP Quantum Well Nanopillar Lasers on Silicon.

    Science.gov (United States)

    Schuster, Fabian; Kapraun, Jonas; Malheiros-Silveira, Gilliard N; Deshpande, Saniya; Chang-Hasnain, Connie J

    2017-04-12

    In this Letter, we report the site-controlled growth of InP nanolasers on a silicon substrate with patterned SiO 2 nanomasks by low-temperature metal-organic chemical vapor deposition, compatible with silicon complementary metal-oxide-semiconductor (CMOS) post-processing. A two-step growth procedure is presented to achieve smooth wurtzite faceting of vertical nanopillars. By incorporating InGaAs multiquantum wells, the nanopillar emission can be tuned over a wide spectral range. Enhanced quality factors of the intrinsic InP nanopillar cavities promote lasing at 0.87 and 1.21 μm, located within two important optical telecommunication bands. This is the first demonstration of a site-controlled III-V nanolaser monolithically integrated on silicon with a silicon-transparent emission wavelength, paving the way for energy-efficient on-chip optical links at typical telecommunication wavelengths.

  7. Electric vehicle battery charging algorithm using PMSM windings and an inverter as an active rectifier

    DEFF Research Database (Denmark)

    Zaja, Mario; Oprea, Matei-lon; Suárez, Carlos Gómez

    2014-01-01

    for battery charging. Alternatively, charging could be done using the motor windings as grid side inductors and controlling the inverter to operate as an active boost rectifier. The challenge in this approach is the unequal phase inductances which depend on the rotor position. Another problem appears when...... an integrated charger control algorithm to charge the battery through a permanent magnet synchronous machine (PMSM) windings....

  8. Enhanced Phase-Shifted Current Control for Harmonic Cancellation in Three-Phase Multiple Adjustable Speed Drive Systems

    DEFF Research Database (Denmark)

    Yang, Yongheng; Davari, Pooya; Zare, Firuz

    2017-01-01

    A phase-shifted current control can be employed to mitigate certain harmonics induced by the Diode Rectifiers (DR) and Silicon-Controlled Rectifiers (SCR) as the front-ends of multiple parallel Adjustable Speed Drive (ASD) systems. However, the effectiveness of the phase-shifted control relies...... on the loading condition of each drive unit as well as the number of drives in parallel. In order to enhance the harmonic cancellation by means of the phase-shifted current control, the currents drawn by the rectifiers should be maintained almost at the same level. Thus, this paper firstly analyzes the impact...... of unequal loading among the parallel drives, and a scheme to enhance the performance is introduced to improve the quality of the total grid current, where partial loading operation should be enabled. Simulation and experimental case studies on multidrive systems have demonstrated that the enhanced phase...

  9. Reduction of Harmonics by 18-Pulse Rectifier

    Directory of Open Access Journals (Sweden)

    Stanislav Kocman

    2008-01-01

    Full Text Available Operation of such electrical devices as data processing and electronics devices, adjustable speed drives or uninterruptible power supply can cause problems by generating harmonic currents into the network, from which they are supplied. Effects of these harmonic currents are various, they can get worse the quality of supply voltage in the network or to have negative influences on devices connected to this network. There are various technical solutions for reduction of harmonics. One of them is using of multi-pulse rectifiers, whereas the 18-pulse rectifier in the structure of adjustable speed drive is briefly presented in this paper including some results of its behaviour. The examined experimental measurements confirmed its very good efficiency in the harmonic mitigation.

  10. LabVIEW-based control and acquisition system for the dosimetric characterization of a silicon strip detector.

    Science.gov (United States)

    Ovejero, M C; Pérez Vega-Leal, A; Gallardo, M I; Espino, J M; Selva, A; Cortés-Giraldo, M A; Arráns, R

    2017-02-01

    The aim of this work is to present a new data acquisition, control, and analysis software system written in LabVIEW. This system has been designed to obtain the dosimetry of a silicon strip detector in polyethylene. It allows the full automation of the experiments and data analysis required for the dosimetric characterization of silicon detectors. It becomes a useful tool that can be applied in the daily routine check of a beam accelerator.

  11. Site-controlled fabrication of silicon nanotips by indentation-induced selective etching

    Science.gov (United States)

    Jin, Chenning; Yu, Bingjun; Liu, Xiaoxiao; Xiao, Chen; Wang, Hongbo; Jiang, Shulan; Wu, Jiang; Liu, Huiyun; Qian, Linmao

    2017-12-01

    In the present study, the indentation-induced selective etching approach is proposed to fabricate site-controlled pyramidal nanotips on Si(100) surface. Without any masks, the site-controlled nanofabrication can be realized by nanoindentation and post etching in potassium hydroxide (KOH) solution. The effect of indentation force and etching time on the formation of pyramidal nanotips was investigated. It is found that the height and radius of the pyramidal nanotips increase with the indentation force or etching time, while long-time etching can lead to the collapse of the tips. The formation of pyramidal tips is ascribed to the anisotropic etching of silicon and etching stop of (111) crystal planes in KOH aqueous solution. The capability of this fabrication method was further demonstrated by producing various tip arrays on silicon surface by selective etching of the site-controlled indent patterns, and the maximum height difference of these tips is less than 10 nm. The indentation-induced selective etching provides a new strategy to fabricate well site-controlled tip arrays for multi-probe SPM system, Si nanostructure-based sensors and high-quality information storage.

  12. Engineered Asymmetric Composite Membranes with Rectifying Properties.

    Science.gov (United States)

    Wen, Liping; Xiao, Kai; Sainath, Annadanam V Sesha; Komura, Motonori; Kong, Xiang-Yu; Xie, Ganhua; Zhang, Zhen; Tian, Ye; Iyoda, Tomokazu; Jiang, Lei

    2016-01-27

    Asymmetric composite membranes with rectifying properties are developed by grafting pH-stimulus-responsive materials onto the top layer of the composite structure, which is prepared by two novel block copolymers using a phase-separation technique. This engineered asymmetric composite membrane shows potential applications in sensors, filtration, and nanofluidic devices. © 2015 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

  13. Implementation of atomic layer etching of silicon: Scaling parameters, feasibility, and profile control

    Energy Technology Data Exchange (ETDEWEB)

    Ranjan, Alok, E-mail: alok.ranjan@us.tel.com; Wang, Mingmei; Sherpa, Sonam D.; Rastogi, Vinayak [TEL Technology Center, America LLC, 255 Fuller Road, Suite 214, Albany, New York 12203 (United States); Koshiishi, Akira [Tokyo Electron Miyagi, Ltd., 1 Techno-Hills, Taiwa-cho, Kurokawa-gun, Miyagi, 9813629 (Japan); Ventzek, Peter L. G. [Tokyo Electron America, Inc., 2400 Grove Blvd., Austin, Texas 78741 (United States)

    2016-05-15

    Atomic or layer by layer etching of silicon exploits temporally segregated self-limiting adsorption and material removal steps to mitigate the problems associated with continuous or quasicontinuous (pulsed) plasma processes: selectivity loss, damage, and profile control. Successful implementation of atomic layer etching requires careful choice of the plasma parameters for adsorption and desorption steps. This paper illustrates how process parameters can be arrived at through basic scaling exercises, modeling and simulation, and fundamental experimental tests of their predictions. Using chlorine and argon plasma in a radial line slot antenna plasma source as a platform, the authors illustrate how cycle time, ion energy, and radical to ion ratio can be manipulated to manage the deviation from ideality when cycle times are shortened or purges are incomplete. Cell based Monte Carlo feature scale modeling is used to illustrate profile outcomes. Experimental results of atomic layer etching processes are illustrated on silicon line and space structures such that iso-dense bias and aspect ratio dependent free profiles are produced. Experimental results also illustrate the profile control margin as processes move from atomic layer to multilayer by layer etching. The consequence of not controlling contamination (e.g., oxygen) is shown to result in deposition and roughness generation.

  14. Thirty-six pulse rectifier scheme based on zigzag auto-connected transformer

    Directory of Open Access Journals (Sweden)

    Xiao-Qiang Chen

    2016-03-01

    Full Text Available In this paper, a low kilo-volt-ampere rating zigzag connected autotransformer based 36-pulse rectifier system supplying vector controlled induction motor drives (VCIMD is designed, modeled and simulated. Detailed design procedure and magnetic rating calculation of the proposed autotransformer and interphase reactor is studied. Moreover, the design process of the autotransformer is modified to make it suitable for retrofit applications. Simulation results confirm that the proposed 36-pulse rectifier system is able to suppress less than 35th harmonics in the utility line current. The influence of load variation and load character is also studied to demonstrate the performance and effectiveness of the proposed 36-pulse rectifiers. A set of power quality indices at AC mains and DC link are presented to compare the performance of 6-, 24- and 36-pulse AC-DC converters.

  15. Robust and reliable rectifier based on electronic inductor with improved performance

    DEFF Research Database (Denmark)

    Singh, Yash Veer; Rasmussen, Peter Omand; Andersen, Torben Ole

    2014-01-01

    of the rectifier, peak to peak voltage ripples to the front end of the inverter reduces significantly by the ESI, and it increases lifetime of the capacitor connected at the output and also reduces the voltage stress of the active power semiconductors of the inverter if any connected to the output. In this paper...... harmonic distortions (THDs) of the ac mains current in a three phase diode bridge rectifier. The ESI reduces the low frequency ripples and controls the intermediate dc-link voltage to a dc value and peak value of the mains current also reduces. In case of an inverter connected to the output...

  16. Control of the Gas Flow in an Industrial Directional Solidification Furnace for Production of High Purity Multicrystalline Silicon Ingots

    Directory of Open Access Journals (Sweden)

    Lijun Liu

    2015-01-01

    Full Text Available A crucible cover was designed as gas guidance to control the gas flow in an industrial directional solidification furnace for producing high purity multicrystalline silicon. Three cover designs were compared to investigate their effect on impurity transport in the furnace and contamination of the silicon melt. Global simulations of coupled oxygen (O and carbon (C transport were carried out to predict the SiO and CO gases in the furnace as well as the O and C distributions in the silicon melt. Cases with and without chemical reaction on the cover surfaces were investigated. It was found that the cover design has little effect on the O concentration in the silicon melt; however, it significantly influences CO gas transport in the furnace chamber and C contamination in the melt. For covers made of metal or with a coating on their surfaces, an optimal cover design can produce a silicon melt free of C contamination. Even for a graphite cover without a coating, the carbon concentration in the silicon melt can be reduced by one order of magnitude. The simulation results demonstrate a method to control the contamination of C impurities in an industrial directional solidification furnace by crucible cover design.

  17. Energy-harvesting shock absorber with a mechanical motion rectifier

    Science.gov (United States)

    Li, Zhongjie; Zuo, Lei; Kuang, Jian; Luhrs, George

    2013-02-01

    Energy-harvesting shock absorbers are able to recover the energy otherwise dissipated in the suspension vibration while simultaneously suppressing the vibration induced by road roughness. They can work as a controllable damper as well as an energy generator. An innovative design of regenerative shock absorbers is proposed in this paper, with the advantage of significantly improving the energy harvesting efficiency and reducing the impact forces caused by oscillation. The key component is a unique motion mechanism, which we called ‘mechanical motion rectifier (MMR)’, to convert the oscillatory vibration into unidirectional rotation of the generator. An implementation of a MMR-based harvester with high compactness is introduced and prototyped. A dynamic model is created to analyze the general properties of the motion rectifier by making an analogy between mechanical systems and electrical circuits. The model is capable of analyzing electrical and mechanical components at the same time. Both simulation and experiments are carried out to verify the modeling and the advantages. The prototype achieved over 60% efficiency at high frequency, much better than conventional regenerative shock absorbers in oscillatory motion. Furthermore, road tests are done to demonstrate the feasibility of the MMR shock absorber, in which more than 15 Watts of electricity is harvested while driving at 15 mph on a smooth paved road. The MMR-based design can also be used for other applications of vibration energy harvesting, such as from tall buildings or long bridges.

  18. Energy-harvesting shock absorber with a mechanical motion rectifier

    International Nuclear Information System (INIS)

    Li, Zhongjie; Zuo, Lei; Kuang, Jian; Luhrs, George

    2013-01-01

    Energy-harvesting shock absorbers are able to recover the energy otherwise dissipated in the suspension vibration while simultaneously suppressing the vibration induced by road roughness. They can work as a controllable damper as well as an energy generator. An innovative design of regenerative shock absorbers is proposed in this paper, with the advantage of significantly improving the energy harvesting efficiency and reducing the impact forces caused by oscillation. The key component is a unique motion mechanism, which we called ‘mechanical motion rectifier (MMR)’, to convert the oscillatory vibration into unidirectional rotation of the generator. An implementation of a MMR-based harvester with high compactness is introduced and prototyped. A dynamic model is created to analyze the general properties of the motion rectifier by making an analogy between mechanical systems and electrical circuits. The model is capable of analyzing electrical and mechanical components at the same time. Both simulation and experiments are carried out to verify the modeling and the advantages. The prototype achieved over 60% efficiency at high frequency, much better than conventional regenerative shock absorbers in oscillatory motion. Furthermore, road tests are done to demonstrate the feasibility of the MMR shock absorber, in which more than 15 Watts of electricity is harvested while driving at 15 mph on a smooth paved road. The MMR-based design can also be used for other applications of vibration energy harvesting, such as from tall buildings or long bridges. (paper)

  19. Boosting the signal: Endothelial inward rectifier K+ channels.

    Science.gov (United States)

    Jackson, William F

    2017-04-01

    Endothelial cells express a diverse array of ion channels including members of the strong inward rectifier family composed of K IR 2 subunits. These two-membrane spanning domain channels are modulated by their lipid environment, and exist in macromolecular signaling complexes with receptors, protein kinases and other ion channels. Inward rectifier K + channel (K IR ) currents display a region of negative slope conductance at membrane potentials positive to the K + equilibrium potential that allows outward current through the channels to be activated by membrane hyperpolarization, permitting K IR to amplify hyperpolarization induced by other K + channels and ion transporters. Increases in extracellular K + concentration activate K IR allowing them to sense extracellular K + concentration and transduce this change into membrane hyperpolarization. These properties position K IR to participate in the mechanism of action of hyperpolarizing vasodilators and contribute to cell-cell conduction of hyperpolarization along the wall of microvessels. The expression of K IR in capillaries in electrically active tissues may allow K IR to sense extracellular K + , contributing to functional hyperemia. Understanding the regulation of expression and function of microvascular endothelial K IR will improve our understanding of the control of blood flow in the microcirculation in health and disease and may provide new targets for the development of therapeutics in the future. © 2016 John Wiley & Sons Ltd.

  20. Study on control of defect mode in hybrid mirror chirped porous silicon photonic crystal

    Science.gov (United States)

    Chen, Ying; Luo, Pei; Han, Yangyang; Cui, Xingning; He, Lei

    2018-03-01

    Based on the optical resonance principle and the tight-binding theory, a hybrid mirror chirped porous silicon photonic crystal is proposed. The control of the defect mode in hybrid mirror chirped porous silicon photonic crystal is studied. Through the numerical simulation, the control regulations of the defect modes resulted by the number of the periodical layers for the fundamental unit and the cascading number of the chirped structures are analyzed, and the split and the degeneration of the defect modes resulted by the change of the relative location between the mirror structures and the quasi-mirror structures are discussed. The simulation results show that the band gap would be broadened with the increase of the chirp quantity and the layer number of unilateral chirp. Adjusting the structural parameters of the hybrid mirror structure, the multimode characteristics will occur in the band gap. The more the cascading number of the chirped units, the more the number of the filtering channels will be. In addition, with the increase of the relative location between the mirror structures and the quasi-mirror structures, the degeneration of the defect modes will occur and can obtain high Q value. The structure can provide effective theoretical references for the design the multi-channel filters and high Q value sensors.

  1. Gold nanoparticle growth control - Implementing novel wet chemistry method on silicon substrate

    KAUST Repository

    Al-Ameer, Ammar

    2013-04-01

    Controlling particle size, shape, nucleation, and self-assembly on surfaces are some of the main challenges facing electronic device fabrication. In this work, growth of gold nanoparticles over a wide range of sizes was investigated by using a novel wet chemical method, where potassium iodide is used as the reducing solution and gold chloride as the metal precursor, on silicon substrates. Four parameters were studied: soaking time, solution temperature, concentration of the solution of gold chloride, and surface pre-treatment of the substrate. Synthesized nanoparticles were then characterized using scanning electron microscopy (SEM). The precise control of the location and order of the grown gold overlayer was achieved by using focused ion beam (FIB) patterning of a silicon surface, pre-treated with potassium iodide. By varying the soaking time and temperature, different particle sizes and shapes were obtained. Flat geometrical shapes and spherical shapes were observed. We believe, that the method described in this work is potentially a straightforward and efficient way to fabricate gold contacts for microelectronics. © 2013 IEEE.

  2. Monochromator for synchrotron light with temperature controlled by electrical current on silicon crystal

    Energy Technology Data Exchange (ETDEWEB)

    Cusatis, Cesar; Souza, Paulo E.N. [Universidade Federal do Parana (LORXI/UFPR), Curitiba, PR (Brazil). Dept. de Fisica. Lab. de Optica de Raios X e Instrumentacao; Franco, Margareth Kobayaski; Kakuno, Edson [Laboratorio Nacional de Luz Sincroton (LNLS), Campinas, SP (Brazil); Gobbi, Angelo; Carvalho Junior, Wilson de [Centro de Pesquisa e Desenvolvimento em Telecomunicacoes (CPqD), Campinas, SP (Brazil)

    2011-07-01

    Full text. doped silicon crystal was used simultaneously as a monochromator, sensor and actuator in such way that its temperature could be controlled. Ohmic contacts allowed resistance measurements on a perfect silicon crystal, which were correlated to its temperature. Using the ohmic contacts, an electrical current caused Joule heating on the monochromator that was used to control its temperature. A simple stand-alone electronic box controlled the system. The device was built and tested with white beam synchrotron light on the double crystal monochromator of the XRD line of LNLS, Laboratorio Nacional de Luz Sincrotron, Campinas. The first crystal of a double crystal monochromator determines the energy that is delivered to a synchrotron experimental station and its temperature instability is a major source of energy and intensity instability. If the (333) silicon monochromator is at theta Bragg near 45 degree the variation of the diffraction angle is around one second of arc per degree Kelvin. It may take several minutes for the first crystal temperature to stabilize at the beginning of the station operation when the crystal and its environment are cold. With water refrigeration, the average overall temperature of the crystal may be constant, but the temperature of the surface changes with and without the white beam. The time used to wait for stabilization of the beam energy/intensity is lost unless the temperature of the crystal surface is kept constant. One solution for keeping the temperature of the monochromator and its environment constant or nearly constant is Joule heating it with a controlled small electrical current flowing on the surface of a doped perfect crystal. When the white beam is on, this small amount of extra power will be more concentrated at the beam footpath because the resistance is lower in this region due to the higher temperature. In addition, if the crystal itself is used to detect the temperature variation by measuring the electrical

  3. Controlled ion-beam transformation of silicon bipolar microwave power transistor's characteristics

    International Nuclear Information System (INIS)

    Solodukha, V.A.; Snitovskij, Yu.P.

    2015-01-01

    In this article, a method for changing the silicon bipolar microwave power transistor's characteristics in a direct and deliberate manner by modifying the chemical composition at the molybdenum - silicon boundary, the electro-physical properties of molybdenum - silicon contacts, and the electrophysical characteristics of transistor structure areas by the phosphorus ions irradiation of generated ohmic molybdenum - silicon contacts to the transistor emitters is proposed for the first time. The possibilities of this method are investigated and confirmed experimentally. (authors)

  4. Diode rectifier bridge-based structure for DFIG-based wind turbine

    DEFF Research Database (Denmark)

    Zhu, Rongwu; Chen, Zhe; Wu, Xiaojie

    2015-01-01

    This paper proposes a new structure for the doubly-fed induction generator (DFIG)-based wind turbine. The proposed structure consists of a DFIG controlled by a partial rated power converter in the rotor side, a three-phase diode rectifier bridge (DRB) connected to the stator, and a DC/AC full rated...

  5. Stability Improvements of an LCL-filter based Three-phase Active Rectifier

    DEFF Research Database (Denmark)

    Liserre, Marco; Dell'Aquila, Antonio; Blaabjerg, Frede

    2002-01-01

    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...

  6. Engineering of silicon surfaces at the micro- and nanoscales for cell adhesion and migration control

    Directory of Open Access Journals (Sweden)

    Torres-Costa V

    2012-02-01

    Full Text Available Vicente Torres-Costa1, Gonzalo Martínez-Muñoz2, Vanessa Sánchez-Vaquero3, Álvaro Muñoz-Noval1, Laura González-Méndez3, Esther Punzón-Quijorna1,4, Darío Gallach-Pérez1, Miguel Manso-Silván1, Aurelio Climent-Font1,4, Josefa P García-Ruiz3, Raúl J Martín-Palma11Department of Applied Physics, 2Department of Computer Science, 3Department of Molecular Biology, 4Centre for Micro Analysis of Materials, Universidad Autónoma de Madrid, Madrid, SpainAbstract: The engineering of surface patterns is a powerful tool for analyzing cellular communication factors involved in the processes of adhesion, migration, and expansion, which can have a notable impact on therapeutic applications including tissue engineering. In this regard, the main objective of this research was to fabricate patterned and textured surfaces at micron- and nanoscale levels, respectively, with very different chemical and topographic characteristics to control cell–substrate interactions. For this task, one-dimensional (1-D and two-dimensional (2-D patterns combining silicon and nanostructured porous silicon were engineered by ion beam irradiation and subsequent electrochemical etch. The experimental results show that under the influence of chemical and morphological stimuli, human mesenchymal stem cells polarize and move directionally toward or away from the particular stimulus. Furthermore, a computational model was developed aiming at understanding cell behavior by reproducing the surface distribution and migration of human mesenchymal stem cells observed experimentally.Keywords: surface patterns, silicon, hMSCs, ion-beam patterning

  7. Accurate control of oxygen level in cells during culture on silicone rubber membranes with application to stem cell differentiation.

    Science.gov (United States)

    Powers, Daryl E; Millman, Jeffrey R; Bonner-Weir, Susan; Rappel, Michael J; Colton, Clark K

    2010-01-01

    Oxygen level in mammalian cell culture is often controlled by placing culture vessels in humidified incubators with a defined gas phase partial pressure of oxygen (pO(2gas)). Because the cells are consuming oxygen supplied by diffusion, a difference between pO(2gas) and that experienced by the cells (pO(2cell)) arises, which is maximal when cells are cultured in vessels with little or no oxygen permeability. Here, we demonstrate theoretically that highly oxygen-permeable silicone rubber membranes can be used to control pO(2cell) during culture of cells in monolayers and aggregates much more accurately and can achieve more rapid transient response following a disturbance than on polystyrene and fluorinated ethylene-propylene copolymer membranes. Cell attachment on silicone rubber was achieved by physical adsorption of fibronectin or Matrigel. We use these membranes for the differentiation of mouse embryonic stem cells to cardiomyocytes and compare the results with culture on polystyrene or on silicone rubber on top of polystyrene. The fraction of cells that are cardiomyocyte-like increases with decreasing pO(2) only when using oxygen-permeable silicone membrane-based dishs, which contract on silicone rubber but not polystyrene. The high permeability of silicone rubber results in pO(2cell) being equal to pO(2gas) at the tissue-membrane interface. This, together with geometric information from histological sections, facilitates development of a model from which the pO(2) distribution within the resulting aggregates is computed. Silicone rubber membranes have significant advantages over polystyrene in controlling pO(2cell), and these results suggest they are a valuable tool for investigating pO(2) effects in many applications, such as stem cell differentiation. Copyright 2009 American Institute of Chemical Engineers

  8. The Detector Control Unit An ASIC for the monitoring of the CMS silicon tracker

    CERN Document Server

    Magazzù, G; Moreira, P

    2004-01-01

    The Detector Control Unit (DCU) is an ASIC developed as the central building block of a monitoring system for the CMS Tracker. Leakage currents in the Silicon detectors, power supply voltages of the readout electronics and local temperatures will be monitored in order to guarantee safe operating conditions during the 10-years lifetime in the LHC environment. All these measurements can be performed by an A/D converter preceded by an analog multiplexer and properly interfaced to the central control system. The requirements in terms of radiation tolerance, low-power dissipation and integration with the rest of the system led to the design of a custom integrated circuit. Its structure and characteristics are described in this paper. (6 refs).

  9. Test of the CMS microstrip silicon tracker readout and control system

    CERN Document Server

    Zghiche, A

    2001-01-01

    The Microstrip Silicon tracker of the CMS detector is designed to provide robust particle tracking and vertex reconstruction within a strong magnetic field in the high luminosity environment of the LHC. The Tracker readout system employs Front-End Driver cards to digitize and buffer the analogue data arriving via optical links from on detector pipeline chips. The control chain of the front-end electronic is built to operate via optical fibers in order to shield the communications from the outside noise. Components close to the final design have been assembled to be tested in the X5 beam area at CERN where a dedicated 25 ns temporal structure beam has been made available by the SPS. This paper describes the hardware and the software developed for readout and control of data acquired by the front-end electronics operating at 40 MHz, Some preliminary results of the tests performed in the 25 ns beam are also given. (8 refs).

  10. Development and implementation of quality control strategies for CMS silicon strip tracker modules

    CERN Document Server

    Dirkes, Guido

    The LHC will explore physics at the energy frontier and will address many open questions in particle physics, like the search for the Higgs boson or Supersymmetry. For both high resolution track and vertex reconstruction is vital. The CMS silicon tracker consists of 15232 detector modules. Production and assembly of these will span two and a half years period, during which the quality control chain has to ensure functionality and reliability of the modules produced. The CMS group in Karlsruhe will produce and qualify 1600 modules. Therefore automatic test systems are developed and test strategies are worked out. Already during the RnD phase, first prototype tests were performed and some weak points of the design were uncovered. Two test stations are built. One focuses on a fast functionality test, including an active thermal cycle. The other focuses on debugging and repair requirements, including additional test options with lasers, radioactive sources, probes and infrared LEDs. For quality control measuremen...

  11. In situ nanoscale refinement by highly controllable etching of the (111) silicon crystal plane and its influence on the enhanced electrical property of a silicon nanowire

    International Nuclear Information System (INIS)

    Gong Yibin; Dai Pengfei; Gao Anran; Li Tie; Zhou Ping; Wang Yuelin

    2011-01-01

    Nanoscale refinement on a (100) oriented silicon-on-insulator (SOI) wafer was introduced by using tetra-methyl-ammonium hydroxide (TMAH, 25 wt%) anisotropic silicon etchant, with temperature kept at 50 °C to achieve precise etching of the (111) crystal plane. Specifically for a silicon nanowire (SiNW) with oxide sidewall protection, the in situ TMAH process enabled effective size reduction in both lateral (2.3 nm/min) and vertical (1.7 nm/min) dimensions. A sub-50 nm SiNW with a length of microns with uniform triangular cross-section was achieved accordingly, yielding enhanced field effect transistor (FET) characteristics in comparison with its 100 nm-wide pre-refining counterpart, which demonstrated the feasibility of this highly controllable refinement process. Detailed examination revealed that the high surface quality of the (111) plane, as well as the bulk depletion property should be the causes of this electrical enhancement, which implies the great potential of the as-made cost-effective SiNW FET device in many fields. (semiconductor materials)

  12. High Voltage GaN Schottky Rectifiers

    Energy Technology Data Exchange (ETDEWEB)

    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

    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.

  13. FF-LYNX: protocol and interfaces for the control and readout of future Silicon detectors

    Energy Technology Data Exchange (ETDEWEB)

    Amendola, A; Bianchi, G; Fanucci, L; Saponara, S; Tongiani, C [Universita di Pisa, Dipartimento di Ingegneria dell' Informazione (DII-EIT), Via G. Caruso 16, 56122 Pisa (Italy); Castaldi, R; Minuti, M; Verdini, P G [INFN, Sezione di Pisa, Largo B. Pontecorvo 3, 56018 Pisa (Italy); Incandela, J; Magazzu, G; Rossin, R, E-mail: Guido.Magazzu@pi.infn.i [University of California at Santa Barbara (UCSB), Department of Physics, 5113 Broida Hall, CA 93106 Santa Barbara (United States)

    2010-06-15

    The FF-LYNX protocol provides an innovative solution for the integrated distribution of Timing, Trigger and Control signals and the data readout in future High Energy Physics experiments. Transmitter and receiver interfaces implementing the FF-LYNX protocol have been simulated with a high-level simulator and in an FPGA based emulator. The design of the interfaces in a commercial CMOS technology as radiation tolerant and low power modules is ongoing and the submission of a test circuit is foreseen in fall 2010. The key features of the protocol are described in this paper as well as its possible application for the transmission from Silicon Trackers to trigger processors with short and constant latency of data to be used for the L1 trigger generation.

  14. Stark tuning and electrical charge state control of single divacancies in silicon carbide

    Science.gov (United States)

    de las Casas, Charles F.; Christle, David J.; Ul Hassan, Jawad; Ohshima, Takeshi; Son, Nguyen T.; Awschalom, David D.

    2017-12-01

    Neutrally charged divacancies in silicon carbide (SiC) are paramagnetic color centers whose long coherence times and near-telecom operating wavelengths make them promising for scalable quantum communication technologies compatible with existing fiber optic networks. However, local strain inhomogeneity can randomly perturb their optical transition frequencies, which degrades the indistinguishability of photons emitted from separate defects and hinders their coupling to optical cavities. Here, we show that electric fields can be used to tune the optical transition frequencies of single neutral divacancy defects in 4H-SiC over a range of several GHz via the DC Stark effect. The same technique can also control the charge state of the defect on microsecond timescales, which we use to stabilize unstable or non-neutral divacancies into their neutral charge state. Using fluorescence-based charge state detection, we show that both 975 nm and 1130 nm excitation can prepare their neutral charge state with near unity efficiency.

  15. "Thunderstruck": Plasma-Polymer-Coated Porous Silicon Microparticles As a Controlled Drug Delivery System.

    Science.gov (United States)

    McInnes, Steven J P; Michl, Thomas D; Delalat, Bahman; Al-Bataineh, Sameer A; Coad, Bryan R; Vasilev, Krasimir; Griesser, Hans J; Voelcker, Nicolas H

    2016-02-01

    Controlling the release kinetics from a drug carrier is crucial to maintain a drug's therapeutic window. We report the use of biodegradable porous silicon microparticles (pSi MPs) loaded with the anticancer drug camphothecin, followed by a plasma polymer overcoating using a loudspeaker plasma reactor. Homogenous "Teflon-like" coatings were achieved by tumbling the particles by playing AC/DC's song "Thunderstruck". The overcoating resulted in a markedly slower release of the cytotoxic drug, and this effect correlated positively with the plasma polymer coating times, ranging from 2-fold up to more than 100-fold. Ultimately, upon characterizing and verifying pSi MP production, loading, and coating with analytical methods such as time-of-flight secondary ion mass spectrometry, scanning electron microscopy, thermal gravimetry, water contact angle measurements, and fluorescence microscopy, human neuroblastoma cells were challenged with pSi MPs in an in vitro assay, revealing a significant time delay in cell death onset.

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

    KAUST Repository

    Wang, Hao; Chroneos, Alexander I.; Londos, Charalampos A.; Sgourou, Efstratia N.; Schwingenschlö gl, Udo

    2014-01-01

    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. © 2014 the Owner Societies.

  17. Electrical leakage phenomenon in heteroepitaxial cubic silicon carbide on silicon

    Science.gov (United States)

    Pradeepkumar, Aiswarya; Zielinski, Marcin; Bosi, Matteo; Verzellesi, Giovanni; Gaskill, D. Kurt; Iacopi, Francesca

    2018-06-01

    Heteroepitaxial 3C-SiC films on silicon substrates are of technological interest as enablers to integrate the excellent electrical, electronic, mechanical, thermal, and epitaxial properties of bulk silicon carbide into well-established silicon technologies. One critical bottleneck of this integration is the establishment of a stable and reliable electronic junction at the heteroepitaxial interface of the n-type SiC with the silicon substrate. We have thus investigated in detail the electrical and transport properties of heteroepitaxial cubic silicon carbide films grown via different methods on low-doped and high-resistivity silicon substrates by using van der Pauw Hall and transfer length measurements as test vehicles. We have found that Si and C intermixing upon or after growth, particularly by the diffusion of carbon into the silicon matrix, creates extensive interstitial carbon traps and hampers the formation of a stable rectifying or insulating junction at the SiC/Si interface. Although a reliable p-n junction may not be realistic in the SiC/Si system, we can achieve, from a point of view of the electrical isolation of in-plane SiC structures, leakage suppression through the substrate by using a high-resistivity silicon substrate coupled with deep recess etching in between the SiC structures.

  18. Silicone Doped Chitosan-Acrylamide Coencapsulated Urea Fertilizer: An Approach to Controlled Release Fertilizers

    Directory of Open Access Journals (Sweden)

    Sempeho Ibahati Siafu

    2017-01-01

    Full Text Available In the absence of special management practices, urea is known to undergo chemical transformations resulting in severe losses (≈60–70% of total fertilizer applied. In an attempt to design urea controlled release fertilizers in order to counterbalance the 60–70% loss, urea was cross-linked with chitosan and acrylamide under refluxed in situ copolymerization technique; the procedures were repeated with silicone doping prior cross-linking with MBA. The particles were characterized with FTIR/ATR, EDX, XRD, and SEM. The IR bands observed within 3426–409 cm−1 revealed the formation of new bands after coencapsulation for the νγN-H, νβN-H, νOH, νsNH2, νCH2, νC=O, δ′NH2, νC=C, δNH2, νC-N, βCH3, $C-N, γNH2, νC=O, and $CH2. Crystallinity indices for urea with and without silicone doping were found to be 50.9% and 72.1%, respectively, with a distinctive split peak at (d 12.30°. The formation of Microdunes and Microballs 3D network sized 0.64 μm was noted. Release profiles demonstrated that 80% N was released in a period of 30 days at RT and pH 7. The release patterns exhibited linear and deformed sigmoid release models. Empirically, the findings demonstrated that it is possible to design urea controlled release fertilizers with varying particle sizes and morphologies by using chitosan-acrylamide coencapsulation.

  19. All-electric control of donor nuclear spin qubits in silicon

    Science.gov (United States)

    Sigillito, Anthony J.; Tyryshkin, Alexei M.; Schenkel, Thomas; Houck, Andrew A.; Lyon, Stephen A.

    2017-10-01

    The electronic and nuclear spin degrees of freedom of donor impurities in silicon form ultra-coherent two-level systems that are potentially useful for applications in quantum information and are intrinsically compatible with industrial semiconductor processing. However, because of their smaller gyromagnetic ratios, nuclear spins are more difficult to manipulate than electron spins and are often considered too slow for quantum information processing. Moreover, although alternating current magnetic fields are the most natural choice to drive spin transitions and implement quantum gates, they are difficult to confine spatially to the level of a single donor, thus requiring alternative approaches. In recent years, schemes for all-electrical control of donor spin qubits have been proposed but no experimental demonstrations have been reported yet. Here, we demonstrate a scalable all-electric method for controlling neutral 31P and 75As donor nuclear spins in silicon. Using coplanar photonic bandgap resonators, we drive Rabi oscillations on nuclear spins exclusively using electric fields by employing the donor-bound electron as a quantum transducer, much in the spirit of recent works with single-molecule magnets. The electric field confinement leads to major advantages such as low power requirements, higher qubit densities and faster gate times. Additionally, this approach makes it possible to drive nuclear spin qubits either at their resonance frequency or at its first subharmonic, thus reducing device bandwidth requirements. Double quantum transitions can be driven as well, providing easy access to the full computational manifold of our system and making it convenient to implement nuclear spin-based qudits using 75As donors.

  20. Application data for the PLT stabilizing field rectifier

    International Nuclear Information System (INIS)

    Bronner, G.; Murray, J.G.; Oliaro, G.E.

    1975-11-01

    This paper describes the 12-pulse stabilizing field rectifier used for vertical field production in the Princeton Large Torus (PLT). It is essential that the rectifier be reliable, and protect itself from all faults including induced transient overvoltage produced by switching and plasma instabilities. To this end, computer simulations were run to insure protection under various fault conditions

  1. Engineering the size and density of silicon agglomerates by controlling the initial surface carbonated contamination

    Energy Technology Data Exchange (ETDEWEB)

    Borowik, Ł., E-mail: Lukasz.Borowik@cea.fr [CEA, LETI, MINATEC Campus, 17 rue des Martyrs, 38054 Grenoble Cedex 9 (France); Chevalier, N.; Mariolle, D.; Martinez, E.; Bertin, F.; Chabli, A.; Barbé, J.-C. [CEA, LETI, MINATEC Campus, 17 rue des Martyrs, 38054 Grenoble Cedex 9 (France)

    2013-04-01

    Actually, thermally induced thin-films dewetting silicon in the silicon-on-insulator is a way to obtain silicon agglomerates with a size and a density fixed by the silicon film thickness. In this paper we report a new method to monitor both the size and the density of the Si agglomerates thanks to the deposition of a carbon-like layer. We show that using a 5-nm thick layer of silicon and additional ≤1-nm carbonated layer; we obtain agglomerates sizes ranging from 35 nm to 60 nm with respectively an agglomerate density ranging from 38 μm{sup −2} to 18 μm{sup −2}. Additionally, for the case of strained silicon films an alternative dewetting mechanism can be induced by monitoring the chemical composition of the sample surface.

  2. Silicon Qubits

    Energy Technology Data Exchange (ETDEWEB)

    Ladd, Thaddeus D. [HRL Laboratories, LLC, Malibu, CA (United States); Carroll, Malcolm S. [Sandia National Lab. (SNL-NM), Albuquerque, NM (United States)

    2018-02-28

    Silicon is a promising material candidate for qubits due to the combination of worldwide infrastructure in silicon microelectronics fabrication and the capability to drastically reduce decohering noise channels via chemical purification and isotopic enhancement. However, a variety of challenges in fabrication, control, and measurement leaves unclear the best strategy for fully realizing this material’s future potential. In this article, we survey three basic qubit types: those based on substitutional donors, on metal-oxide-semiconductor (MOS) structures, and on Si/SiGe heterostructures. We also discuss the multiple schema used to define and control Si qubits, which may exploit the manipulation and detection of a single electron charge, the state of a single electron spin, or the collective states of multiple spins. Far from being comprehensive, this article provides a brief orientation to the rapidly evolving field of silicon qubit technology and is intended as an approachable entry point for a researcher new to this field.

  3. Nanofibrous p-n Junction and Its Rectifying Characteristics

    Directory of Open Access Journals (Sweden)

    Jian Fang

    2013-01-01

    Full Text Available Randomly oriented tin oxide (SnO2 nanofibers and poly(3,4-ethylenedioxythiophene-poly(styrenesulfonate/polyvinylpyrrolidone (PEDOT:PSS/PVP nanofibers were prepared by a two-step electrospinning technique to form a layered fibrous mat. The current-voltage measurement revealed that the fibrous mat had an obvious diode-rectifying characteristic. The thickness of the nanofiber layers was found to have a considerable influence on the device resistance and rectifying performance. Such an interesting rectifying property was attributed to the formation of a p-n junction between the fibrous SnO2 and PEDOT:PSS/PVP layers. This is the first report that a rectifying junction can be formed between two layers of electrospun nanofiber mats, and the resulting nanofibrous diode rectifier may find applications in sensors, energy harvest, and electronic textiles.

  4. Effect of argon implantation on solid-state dewetting: control of size and surface density of silicon nanocrystals.

    Science.gov (United States)

    Almadori, Y; Borowik, Ł; Chevalier, N; Barbé, J-C

    2017-01-27

    Thermally induced solid-state dewetting of ultra-thin films on insulators is a process of prime interest, since it is capable of easily forming nanocrystals. If no particular treatment is performed to the film prior to the solid-state dewetting, it is already known that the size, the shape and the density of nanocrystals is governed by the initial film thickness. In this paper, we report a novel approach to control the size and the surface density of silicon nanocrystals based on an argon-implantation preliminary surface treatment. Using 7.5 nm thin layers of silicon, we show that increasing the implantation dose tends to form smaller silicon nanocrystals with diameter and height lower than 50 nm and 30 nm, respectively. Concomitantly, the surface density is increased by a factor greater than 20, going from 5 μm -2 to values over 100 μm -2 .

  5. Superconducting transformers, rectifiers, and switches. (Review paper)

    International Nuclear Information System (INIS)

    Ignatov, V.E.; Koval'kov, G.A.; Moskvitin, A.I.

    Cryogenic rectifiers using power cryotrons have been fabricated by many foreign firms since 1960. Present-day flux pumps require a low voltage power supply (several tens of millivolts) and a high current (kiloamperes). Increasing the power supply voltage will quadratically increase the flux pump losses and, given the limitations of existing materials, are not economically profitable. Present-day, cryotron-type flux pumps can best be used in power systems as a power supply for superconducting magnets, solenoids, storage devices, and superconducting exciting coils for turbogenerators. To increase the voltage of the next generation of transformers for superconducting dc power transmission, a research program must be set up to improve the cryotrons and to develop systems based on a different principle of operation, for example, semiconductor devices based on the principle of the volume effect in the intermediate environment

  6. Creating New VLS Silicon Nanowire Contact Geometries by Controlling Catalyst Migration

    DEFF Research Database (Denmark)

    Alam, Sardar Bilal; Panciera, Federico; Hansen, Ole

    2015-01-01

    The formation of self-assembled contacts between vapor-liquid-solid grown silicon nanowires and flat silicon surfaces was imaged in situ using electron microscopy. By measuring the structural evolution of the contact formation process, we demonstrate how different contact geometries are created b...

  7. Silicon microgyroscope temperature prediction and control system based on BP neural network and Fuzzy-PID control method

    International Nuclear Information System (INIS)

    Xia, Dunzhu; Kong, Lun; Hu, Yiwei; Ni, Peizhen

    2015-01-01

    We present a novel silicon microgyroscope (SMG) temperature prediction and control system in a narrow space. As the temperature of SMG is closely related to its drive mode frequency and driving voltage, a temperature prediction model can be established based on the BP neural network. The simulation results demonstrate that the established temperature prediction model can estimate the temperature in the range of −40 to 60 °C with an error of less than ±0.05 °C. Then, a temperature control system based on the combination of fuzzy logic controller and the increment PID control method is proposed. The simulation results prove that the Fuzzy-PID controller has a smaller steady state error, less rise time and better robustness than the PID controller. This is validated by experimental results that show the Fuzzy-PID control method can achieve high precision in keeping the SMG temperature stable at 55 °C with an error of less than 0.2 °C. The scale factor can be stabilized at 8.7 mV/°/s with a temperature coefficient of 33 ppm °C −1 . ZRO (zero rate output) instability is decreased from 1.10°/s (9.5 mV) to 0.08°/s (0.7 mV) when the temperature control system is implemented over an ambient temperature range of −40 to 60 °C. (paper)

  8. TEMPO/viologen electrochemical heterojunction for diffusion-controlled redox mediation: a highly rectifying bilayer-sandwiched device based on cross-reaction at the interface between dissimilar redox polymers.

    Science.gov (United States)

    Tokue, Hiroshi; Oyaizu, Kenichi; Sukegawa, Takashi; Nishide, Hiroyuki

    2014-03-26

    A couple of totally reversible redox-active molecules, which are different in redox potentials, 2,2,6,6-tetramethylpiperidin-1-oxyl (TEMPO) and viologen (V(2+)), were employed to give rise to a rectified redox conduction effect. Single-layer and bilayer devices were fabricated using polymers containing these sites as pendant groups per repeating unit. The devices were obtained by sandwiching the redox polymer layer(s) with indium tin oxide (ITO)/glass and Pt foil electrodes. Electrochemical measurements of the single-layer device composed of polynorbornene-bearing TEMPO (PTNB) exhibited a diffusion-limited current-voltage response based on the TEMPO(+)/TEMPO exchange reaction, which was almost equivalent to a redox gradient through the PTNB layer depending upon the thickness. The bilayer device gave rise to the current rectification because of the thermodynamically favored cross-reaction between TEMPO(+) and V(+) at the polymer/polymer interface. A current-voltage response obtained for the bilayer device demonstrated a two-step diffusion-limited current behavior as a result of the concurrent V(2+)/V(+) and V(+)/V(0) exchange reactions according to the voltage and suggested that the charge transport process through the device was most likely to be rate-determined by a redox gradient in the polymer layer. Current collection experiments revealed a charge transport balance throughout the device, as a result of the electrochemical stability and robustness of the polymers in both redox states.

  9. Effect of rotor rectifier on motor performance in slip recovery drives

    Energy Technology Data Exchange (ETDEWEB)

    Al Zahawi, B.A.T.; Jones, B.L.; Drury, W.

    1987-01-01

    The static Kramer system, comprising a slip-ring induction motor and a slip energy recovery circuit, is one of the simplest and most efficient forms of ac variable-speed drive. It is sometimes used to upgrade drives which had originally been designed for fixed speed operation, often with substantial energy savings. In such cases, it is important to know how the inclusion of a rectifier in the slip energy recovery circuit affects motor performance. A satisfactory model for the motor-rectifier combination is also needed to provide a sound basis for assessing alternative forms of recovery systems which aim to overcome the principal shortcomings of the drive, namely the magnitude and variability of its reactive power. Despite its simplicity, the Kramer drive presents a formidable analytical challenge. Rigorous analysis is particularly difficult and there is a need for a simpler form of analysis when calculating ratings and steady-state performance. The approach taken in this paper uses a transformer-type model for the motor, and largely analytical expressions for predicting torque, stator power, stator reactive power and rectifier output voltage. Motor resistances, diode characteristics, and the several possible rectifier overlap modes are included. It is shown that the rectifier has an adverse effect on stator reactive power, power factor, and peak torque, particularly at speeds well below synchronous, requiring some derating of motors designed for resistance control and also requiring additional power factor correction. While the analysis does not cater to variations caused by harmonics at some speeds, it does provide a quick, accurate method of predicting performance over most sections of the operating range. 12 refs., 11 figs.

  10. Inhibition of cardiac inward rectifier currents by cationic amphiphilic drugs.

    Science.gov (United States)

    van der Heyden, M A G; Stary-Weinzinger, A; Sanchez-Chapula, J A

    2013-09-01

    Cardiac inward rectifier channels belong to three different classes of the KIR channel protein family. The KIR2.x proteins generate the classical inward rectifier current, IK1, while KIR3 and KIR6 members are responsible for the acetylcholine responsive and ATP sensitive inward rectifier currents IKAch and IKATP, respectively. Aberrant function of these channels has been correlated with severe cardiac arrhythmias, indicating their significant contribution to normal cardiac electrophysiology. A common feature of inward rectifier channels is their dependence on the lipid phosphatidyl-4,5-bisphospate (PIP2) interaction for functional activity. Cationic amphiphilic drugs (CADs) are one of the largest classes of pharmaceutical compounds. Several widely used CADs have been associated with inward rectifier current disturbances, and recent evidence points to interference of the channel-PIP2 interaction as the underlying mechanism of action. Here, we will review how six of these well known drugs, used for treatment in various different conditions, interfere in cardiac inward rectifier functioning. In contrast, KIR channel inhibition by the anionic anesthetic thiopental is achieved by a different mechanism of channel-PIP2 interference. We will discuss the latest basic science insights of functional inward rectifier current characteristics, recently derived KIR channel structures and specific PIP2-receptor interactions at the molecular level and provide insight in how these drugs interfere in the structure-function relationships.

  11. Implementation of Statistical Process Control: Evaluating the Mechanical Performance of a Candidate Silicone Elastomer Docking Seal

    Science.gov (United States)

    Oravec, Heather Ann; Daniels, Christopher C.

    2014-01-01

    The National Aeronautics and Space Administration has been developing a novel docking system to meet the requirements of future exploration missions to low-Earth orbit and beyond. A dynamic gas pressure seal is located at the main interface between the active and passive mating components of the new docking system. This seal is designed to operate in the harsh space environment, but is also to perform within strict loading requirements while maintaining an acceptable level of leak rate. In this study, a candidate silicone elastomer seal was designed, and multiple subscale test articles were manufactured for evaluation purposes. The force required to fully compress each test article at room temperature was quantified and found to be below the maximum allowable load for the docking system. However, a significant amount of scatter was observed in the test results. Due to the stochastic nature of the mechanical performance of this candidate docking seal, a statistical process control technique was implemented to isolate unusual compression behavior from typical mechanical performance. The results of this statistical analysis indicated a lack of process control, suggesting a variation in the manufacturing phase of the process. Further investigation revealed that changes in the manufacturing molding process had occurred which may have influenced the mechanical performance of the seal. This knowledge improves the chance of this and future space seals to satisfy or exceed design specifications.

  12. Controllable Nanoscale Inverted Pyramids for High-Efficient Quasi-Omnidirectional Crystalline Silicon Solar Cells.

    Science.gov (United States)

    Xu, Haiyuan; Zhong, Sihua; Zhuang, Yufeng; Shen, Wenzhong

    2017-11-14

    Nanoscale inverted pyramid structures (NIPs) have always been regarded as one of the most paramount light management schemes to achieve the extraordinary performance in various devices, especially in solar cells, due to their outstanding antireflection ability with relative lower surface enhancement ratio. However, the current approaches to fabricating the NIPs are complicated and not cost-effective for the massive cell production in the photovoltaic industry. Here, controllable NIPs are fabricated on crystalline silicon (c-Si) wafers by Ag catalyzed chemical etching and alkaline modification, which is a preferable all-solution-processed method. Through applying the NIPs to c-Si solar cells and optimizing the cell design, we have successfully achieved highly efficient NIPs textured solar cells with the champion efficiency of 20.5%. Importantly, the NIPs textured solar cells are further demonstrated to possess the quasi-omnidirectional property over the broad sunlight incident angles of approximately 0°-60°. Moreover, the NIPs are theoretically revealed to offer light trapping advantage for ultrathin c-Si solar cells. Hence, the NIPs formed by the controllable method exhibit a great potential to be used in the future photovoltaic industry as surface texture. © 2017 IOP Publishing Ltd.

  13. Use of an amorphous silicon electronic portal imaging device for multileaf collimator quality control and calibration

    International Nuclear Information System (INIS)

    Baker, S J K; Budgell, G J; MacKay, R I

    2005-01-01

    Multileaf collimator (MLC) calibration and quality control is a time-consuming procedure typically involving the processing, scanning and analysis of films to measure leaf and collimator positions. Faster and more reliable calibration procedures are required for these tasks, especially with the introduction of intensity modulated radiotherapy which requires more frequent checking and finer positional leaf tolerances than previously. A routine quality control (QC) technique to measure MLC leaf bank gain and offset, as well as minor offsets (individual leaf position relative to a reference leaf), using an amorphous silicon electronic portal imaging device (EPID) has been developed. The technique also tests the calibration of the primary and back-up collimators. A detailed comparison between film and EPID measurements has been performed for six linear accelerators (linacs) equipped with MLC and amorphous silicon EPIDs. Measurements of field size from 4 to 24 cm with the EPID were systematically smaller than film measurements over all field sizes by 0.4 mm for leaves/back-up collimators and by 0.2 mm for conventional collimators. This effect is due to the gain calibration correction applied by the EPID, resulting in a 'flattening' of primary beam profiles. Linac dependent systematic differences of up to 0.5 mm in individual leaf/collimator positions were also found between EPID and film measurements due to the difference between the mechanical and radiation axes of rotation. When corrections for these systematic differences were applied, the residual random differences between EPID and film were 0.23 mm and 0.26 mm (1 standard deviation) for field size and individual leaf/back-up collimator position, respectively. Measured gains (over a distance of 220 mm) always agreed within 0.4 mm with a standard deviation of 0.17 mm. Minor offset measurements gave a mean agreement between EPID and film of 0.01 ± 0.10 mm (1 standard deviation) after correction for the tilt of the

  14. Cardiac Delayed Rectifier Potassium Channels in Health and Disease

    Science.gov (United States)

    Chen, Lei; Sampson, Kevin J.; Kass, Robert S.

    2016-01-01

    Cardiac delayed rectifier potassium channels conduct outward potassium currents during the plateau phase of action potentials and play pivotal roles in cardiac repolarization. These include IKs, IKr and the atrial specific IKur channels. In this chapter, we will review the molecular identities and biophysical properties of these channels. Mutations in the genes encoding delayed rectifiers lead to loss- or gain-of-function phenotypes, disrupt normal cardiac repolarization and result in various cardiac rhythm disorders, including congenital Long QT Syndrome, Short QT Syndrome and familial atrial fibrillation. We will also discuss the possibility and prospect of using delayed rectifier channels as therapeutic targets to manage cardiac arrhythmia. PMID:27261823

  15. Cardiac Delayed Rectifier Potassium Channels in Health and Disease.

    Science.gov (United States)

    Chen, Lei; Sampson, Kevin J; Kass, Robert S

    2016-06-01

    Cardiac delayed rectifier potassium channels conduct outward potassium currents during the plateau phase of action potentials and play pivotal roles in cardiac repolarization. These include IKs, IKr and the atrial specific IKur channels. In this article, we will review their molecular identities and biophysical properties. Mutations in the genes encoding delayed rectifiers lead to loss- or gain-of-function phenotypes, disrupt normal cardiac repolarization and result in various cardiac rhythm disorders, including congenital Long QT Syndrome, Short QT Syndrome and familial atrial fibrillation. We will also discuss the prospect of using delayed rectifier channels as therapeutic targets to manage cardiac arrhythmia. Copyright © 2016 Elsevier Inc. All rights reserved.

  16. Controlling the optical properties of monocrystalline 3C-SiC heteroepitaxially grown on silicon at low temperatures

    Science.gov (United States)

    Colston, Gerard; Myronov, Maksym

    2017-11-01

    Cubic silicon carbide (3C-SiC) offers an alternative wide bandgap semiconductor to conventional materials such as hexagonal silicon carbide (4H-SiC) or gallium nitride (GaN) for the detection of UV light and can offer a closely lattice matched virtual substrate for subsequent GaN heteroepitaxy. As 3C-SiC can be heteroepitaxially grown on silicon (Si) substrates its optical properties can be manipulated by controlling the thickness and doping concentrations. The optical properties of 3C-SiC epilayers have been characterized by measuring the transmission of light through suspended membranes. Decreasing the thickness of the 3C-SiC epilayers is shown to shift the absorbance edge to lower wavelengths, a result of the indirect bandgap nature of silicon carbide. This property, among others, can be exploited to fabricate very low-cost, tuneable 3C-SiC based UV photodetectors. This study investigates the effect of thickness and doping concentration on the optical properties of 3C-SiC epilayers grown at low temperatures by a standard Si based growth process. The results demonstrate the potential photonic applications of 3C-SiC and its heterogeneous integration into the Si industry.

  17. Coherent scatter-controlled phase-change grating structures in silicon using femtosecond laser pulses.

    Science.gov (United States)

    Fuentes-Edfuf, Yasser; Garcia-Lechuga, Mario; Puerto, Daniel; Florian, Camilo; Garcia-Leis, Adianez; Sanchez-Cortes, Santiago; Solis, Javier; Siegel, Jan

    2017-07-04

    Periodic structures of alternating amorphous-crystalline fringes have been fabricated in silicon using repetitive femtosecond laser exposure (800 nm wavelength and 120 fs duration). The method is based on the interference of the incident laser light with far- and near-field scattered light, leading to local melting at the interference maxima, as demonstrated by femtosecond microscopy. Exploiting this strategy, lines of highly regular amorphous fringes can be written. The fringes have been characterized in detail using optical microscopy combined modelling, which enables a determination of the three-dimensional shape of individual fringes. 2D micro-Raman spectroscopy reveals that the space between amorphous fringes remains crystalline. We demonstrate that the fringe period can be tuned over a range of 410 nm - 13 µm by changing the angle of incidence and inverting the beam scan direction. Fine control over the lateral dimensions, thickness, surface depression and optical contrast of the fringes is obtained via adjustment of pulse number, fluence and spot size. Large-area, highly homogeneous gratings composed of amorphous fringes with micrometer width and millimeter length can readily be fabricated. The here presented fabrication technique is expected to have applications in the fields of optics, nanoelectronics, and mechatronics and should be applicable to other materials.

  18. Method of purifying metallurgical grade silicon employing reduced pressure atmospheric control

    Science.gov (United States)

    Ingle, W. M.; Thompson, S. W.; Chaney, R. E. (Inventor)

    1979-01-01

    A method in which a quartz tube is charged with chunks of metallurgical grade silicon and/or a mixture of such chunks and high purity quartz sand, and impurities from a class including aluminum, boron, as well as certain transition metals including nickel, iron, and manganese is described. The tube is then evacuated and heated to a temperature within a range of 800 C to 1400 C. A stream of gas comprising a reactant, such as silicon tetrafluoride, is continuously delivered at low pressures through the charge for causing a metathetical reaction of impurities of the silicon and the reactant to occur for forming a volatile halide and leaving a residue of silicon of an improved purity. The reactant which included carbon monoxide gas and impurities such as iron and nickel react to form volatile carbonyls.

  19. Stable cycling of double-walled silicon nanotube battery anodes through solid–electrolyte interphase control

    KAUST Repository

    Wu, Hui; Chan, Gerentt; Choi, Jang Wook; Ryu, Ill; Yao, Yan; McDowell, Matthew T.; Lee, Seok Woo; Jackson, Ariel; Yang, Yuan; Hu, Liangbing; Cui, Yi

    2012-01-01

    Although the performance of lithium ion-batteries continues to improve, their energy density and cycle life remain insufficient for applications in consumer electronics, transport and large-scale renewable energy storage 1-5. Silicon has a large

  20. Controlled localised melting in silicon by high dose germanium implantation and flash lamp annealing

    International Nuclear Information System (INIS)

    Voelskow, Matthias; Skorupa, Wolfgang; Pezoldt, Joerg; Kups, Thomas

    2009-01-01

    High intensity light pulse irradiation of monocrystalline silicon wafers is usually accompanied by inhomogeneous surface melting. The aim of the present work is to induce homogeneous buried melting in silicon by germanium implantation and subsequent flash lamp annealing. For this purpose high dose, high energy germanium implantation has been employed to lower the melting temperature of silicon in a predetermined depth region. Subsequent flash lamp irradiation at high energy densities leads to local melting of the germanium rich buried layer, whereby the thickness of the molten layer depends on the irradiation energy density. During the cooling down epitaxial crystallization takes place resulting in a largely defect-free layer. The combination of buried melting and dopant segregation has the potential to produce unusually buried doping profiles or to create strained silicon structures.

  1. Current-voltage characteristics of porous-silicon structures

    International Nuclear Information System (INIS)

    Diligenti, A.; Nannini, A.; Pennelli, G.; Pieri, F.; Fuso, F.; Allegrini, M.

    1996-01-01

    I-V DC characteristics have been measured on metal/porous-silicon structures. In particular, the measurements on metal/free-standing porous-silicon film/metal devices confirmed the result, already obtained, that the metal/porous-silicon interface plays a crucial role in the transport of any device. Four-contacts measurements on free-standing layers showed that the current linearly depends on the voltage and that the conduction process is thermally activated, the activation energy depending on the porous silicon film production parameters. Finally, annealing experiments performed in order to improve the conduction of rectifying contacts, are described

  2. Towards Rectifying Performance at the Molecular Scale.

    Science.gov (United States)

    Zhang, Guang-Ping; Xie, Zhen; Song, Yang; Hu, Gui-Chao; Wang, Chuan-Kui

    2017-10-24

    Molecular diode, proposed by Mark Ratner and Arieh Aviram in 1974, is the first single-molecule device investigated in molecular electronics. As a fundamental device in an electric circuit, molecular diode has attracted an enduring and extensive focus during the past decades. In this review, the theoretical and experimental progresses of both charge-based and spin-based molecular diodes are summarized. For the charge-based molecular diodes, the rectifying properties originated from asymmetric molecules including D-σ-A, D-π-A, D-A, and σ-π type compounds, asymmetric electrodes, asymmetric nanoribbons, and their combination are analyzed. Correspondingly, the rectification mechanisms are discussed in detail. Furthermore, a series of strategies for modulating rectification performance is figured out. Discussion on concept of molecular spin diode is also involved based on a magnetic co-oligomer. At the same time, the intrinsic mechanism as well as the modulation of the spin-current rectification performance is introduced. Finally, several crucial issues that need to be addressed in the future are given.

  3. 2010 NOAA Ortho-rectified Mosaic of Lake Champlain, Vermont

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — This data set contains ortho-rectified mosaic tiles, created as a product from the NOAA Integrated Ocean and Coastal Mapping (IOCM) initiative. The source imagery...

  4. 2012 NOAA Ortho-rectified Color Mosaic of Astoria, Oregon

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — This data set contains ortho-rectified mosaic tiles, created as a product from the NOAA Integrated Ocean and Coastal Mapping (IOCM) initiative. The source imagery...

  5. 2011 NOAA Ortho-rectified Mosaic of Intracoastal Waterway, Texas

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — This data set contains ortho-rectified mosaic tiles, created as a product from the NOAA Integrated Ocean and Coastal Mapping (IOCM) initiative. The source imagery...

  6. 2011 NOAA Ortho-rectified Mosaic of Galveston, Texas

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — This data set contains ortho-rectified mosaic tiles, created as a product from the NOAA Integrated Ocean and Coastal Mapping (IOCM) initiative. The source imagery...

  7. Direct Driven Permanent Magnet Synchronous Generators with Diode Rectifiers for Use in Offshore Wind Turbines

    OpenAIRE

    Reigstad, Tor Inge

    2007-01-01

    This work is focused on direct-driven permanent magnets synchronous generators (PMSG) with diode rectifiers for use in offshore wind turbines. Reactive compensation of the generator, power losses and control of the generator are studied. Configurations for power transmission to onshore point of common connection are also considered. Costs, power losses, reliability and interface with the PMSG are discussed. The purpose of the laboratory tests and simulations are to learn how a PMSG with dio...

  8. Thirty-six pulse rectifier scheme based on zigzag auto-connected transformer

    OpenAIRE

    Xiao-Qiang Chen; Chun-Ling Hao; Hao Qiu; Min Li

    2016-01-01

    In this paper, a low kilo-volt-ampere rating zigzag connected autotransformer based 36-pulse rectifier system supplying vector controlled induction motor drives (VCIMD) is designed, modeled and simulated. Detailed design procedure and magnetic rating calculation of the proposed autotransformer and interphase reactor is studied. Moreover, the design process of the autotransformer is modified to make it suitable for retrofit applications. Simulation results confirm that the proposed 36-pulse re...

  9. Stable cycling of double-walled silicon nanotube battery anodes through solid–electrolyte interphase control

    KAUST Repository

    Wu, Hui

    2012-03-25

    Although the performance of lithium ion-batteries continues to improve, their energy density and cycle life remain insufficient for applications in consumer electronics, transport and large-scale renewable energy storage 1-5. Silicon has a large charge storage capacity and this makes it an attractive anode material, but pulverization during cycling and an unstable solid-electrolyte interphase has limited the cycle life of silicon anodes to hundreds of cycles 6-11. Here, we show that anodes consisting of an active silicon nanotube surrounded by an ion-permeable silicon oxide shell can cycle over 6,000 times in half cells while retaining more than 85% of their initial capacity. The outer surface of the silicon nanotube is prevented from expansion by the oxide shell, and the expanding inner surface is not exposed to the electrolyte, resulting in a stable solid-electrolyte interphase. Batteries containing these double-walled silicon nanotube anodes exhibit charge capacities approximately eight times larger than conventional carbon anodes and charging rates of up to 20C (a rate of 1C corresponds to complete charge or discharge in one hour). © 2012 Macmillan Publishers Limited. All rights reserved.

  10. Noise rectifier based on the two-dimensional electron gas

    Energy Technology Data Exchange (ETDEWEB)

    Cheremisin, M. V., E-mail: tcher_max@yahoo.com [Ioffe Physical-Technical Institute (Russian Federation)

    2012-09-15

    The dc voltage observed at low temperatures in a 2D electron sample in the absence of noticeable external excitations [1] is accounted by the Schottky contact rectification of the noise generated in the measuring circuit. The rectified voltage is shown to depend on the asymmetry of the contact pair. The dependence of the rectified voltage on the noise amplitude first follows the trivial quadratic law, then exhibits a nearly linear behavior, and finally, levels off.

  11. Wireless power transmission for biomedical implants: The role of near-zero threshold CMOS rectifiers.

    Science.gov (United States)

    Mohammadi, Ali; Redoute, Jean-Michel; Yuce, Mehmet R

    2015-01-01

    Biomedical implants require an electronic power conditioning circuitry to provide a stable electrical power supply. The efficiency of wireless power transmission is strongly dependent on the power conditioning circuitry specifically the rectifier. A cross-connected CMOS bridge rectifier is implemented to demonstrate the impact of thresholds of rectifiers on wireless power transfer. The performance of the proposed rectifier is experimentally compared with a conventional Schottky diode full wave rectifier over 9 cm distance of air and tissue medium between the transmitter and receiver. The output voltage generated by the CMOS rectifier across a 1 KΩ resistive load is around twice as much as the Schottky rectifier.

  12. Luminescence in amorphous silicon p-i-n diodes under double-injection dispersive-transport-controlled recombination

    International Nuclear Information System (INIS)

    Han, D.; Wang, K.; Yeh, C.; Yang, L.; Deng, X.; Von Roedern, B.

    1997-01-01

    The temperature and electric-field dependence of the forward bias current and the electroluminescence (EL) in hydrogenated amorphous silicon (a-Si:H) p-i-n and n-i-p diodes have been studied. Both the current and the EL efficiency temperature dependence show three regions depending on either hopping-controlled or multiple-trapping or ballistic transport mechanisms. Comparing the thermalization-controlled geminate recombination processes of photoluminescence to the features of EL, the differences can be explained by transport-controlled nongeminate recombination in trap-rich materials. copyright 1997 The American Physical Society

  13. Silicone metalization

    Energy Technology Data Exchange (ETDEWEB)

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

    2008-12-09

    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.

  14. Size Control of Porous Silicon-Based Nanoparticles via Pore-Wall Thinning.

    Science.gov (United States)

    Secret, Emilie; Leonard, Camille; Kelly, Stefan J; Uhl, Amanda; Cozzan, Clayton; Andrew, Jennifer S

    2016-02-02

    Photoluminescent silicon nanocrystals are very attractive for biomedical and electronic applications. Here a new process is presented to synthesize photoluminescent silicon nanocrystals with diameters smaller than 6 nm from a porous silicon template. These nanoparticles are formed using a pore-wall thinning approach, where the as-etched porous silicon layer is partially oxidized to silica, which is dissolved by a hydrofluoric acid solution, decreasing the pore-wall thickness. This decrease in pore-wall thickness leads to a corresponding decrease in the size of the nanocrystals that make up the pore walls, resulting in the formation of smaller nanoparticles during sonication of the porous silicon. Particle diameters were measured using dynamic light scattering, and these values were compared with the nanocrystallite size within the pore wall as determined from X-ray diffraction. Additionally, an increase in the quantum confinement effect is observed for these particles through an increase in the photoluminescence intensity of the nanoparticles compared with the as-etched nanoparticles, without the need for a further activation step by oxidation after synthesis.

  15. Development and implementation of quality control strategies for CMS silicon strip tracker modules

    International Nuclear Information System (INIS)

    Dirkes, G.

    2003-01-01

    The CMS group in Karlsruhe is involved in the construction of the silicon trackers end-caps and will produce and qualify the 1 600 modules of ring 5. Therefore automatic test systems for module qualification are developed and test strategies are worked out. For the electrical tests a complete readout system is developed, based on readout modules available within the collaboration and extended by home build modules. These are based on a modular approach with less complex functional units attached to a motherboard and includes key functionalities like clock and trigger generation and their distribution, high and low voltage supply and test signal generation usable with lasers or infrared LEDs. The motherboard is connected to a standard PC, hosting a fast ADC, interface cards to the motherboard and the front-end electronics. Already during the R and D phase of this readout system, first prototype tests were performed and some weak points of the design were uncovered, resulting in changes of the electronics design of the front end hybrids. Two test stations are built. The first one focuses on a fast functionality test, which includes an active thermal cycle with readout at -10 C performed for each individual module. The other test station focuses on debugging and repair requirements. It disposes of sufficient space for a flexible use of the system, including the possibility of additional test options with lasers, radioactive sources, probes and LEDs. For quality control measurements at module level it turned out, that LEDs are of good use: Besides external signal generation by running them in a pulsed way, they can be used for constant illumination of sensors, inducing an artificial leakage current. This led to the discovery of gain losses of complete readout chips induced by shorted AC coupling capacitances of several readout channels, which are called pinholes. Therefore pinholes must be unbonded from the front end preamplifier, which requires faultless

  16. Metallurgical Parameters Controlling the Eutectic Silicon Charateristics in Be-Treated Al-Si-Mg Alloys.

    Science.gov (United States)

    Ibrahim, Mohamed F; Elgallad, Emad M; Valtierra, Salvador; Doty, Herbert W; Samuel, Fawzy H

    2016-01-27

    The present work was carried out on Al-7%Si-0.4%Mg-X alloy (where X = Mg, Fe, Sr or Be), where the effect of solidification rate on the eutectic silicon characteristics was investigated. Two solidification rates corresponding to dendrite arm spacings (DAS) of 24 and 65 μm were employed. Samples with 24 μm DAS were solution heat-treated at 540 °C for 5 and 12 h prior to quenching in warm water at 65 °C. Eutectic Si particle charateristics were measured using an image analyzer. The results show that the addition of 0.05% Be leads to partial modification of the Si particles. Full modification was only obtained when Sr was added in an amount of 150-200 ppm, depending on the applied solidification rate. Increasing the amount of Mg to 0.8% in Sr-modified alloys leads to a reduction in the effectiveness of Sr as the main modifier. Similar observations were made when the Fe content was increased in Be-treated alloys due to the Be-Fe interaction. Over-modification results in the precipitation of hard Sr-rich particles, mainly Al₄SrSi₂, whereas overheating causes incipient melting of the Al-Cu eutectic and hence the surrounding matrix. Both factors lead to a deterioration in the alloy mechanical properties. Furthermore, the presence of long, acicular Si particles accelerates the occurrence of fracture and, as a result, yields poor ductility. In low iron (less than 0.1 wt%) Al-Si-Mg alloys, the mechanical properties in the as cast, as well as heat treated conditions, are mainly controlled by the eutectic Si charatersitics. Increasing the iron content and, hence, the volume fraction of Fe-based intermetallics leads to a complex fracture mode.

  17. Metallurgical Parameters Controlling the Eutectic Silicon Charateristics in Be-Treated Al-Si-Mg Alloys

    Directory of Open Access Journals (Sweden)

    Mohamed F. Ibrahim

    2016-01-01

    Full Text Available The present work was carried out on Al-7%Si-0.4%Mg-X alloy (where X = Mg, Fe, Sr or Be, where the effect of solidification rate on the eutectic silicon characteristics was investigated. Two solidification rates corresponding to dendrite arm spacings (DAS of 24 and 65 μm were employed. Samples with 24 μm DAS were solution heat-treated at 540 °C for 5 and 12 h prior to quenching in warm water at 65 °C. Eutectic Si particle charateristics were measured using an image analyzer. The results show that the addition of 0.05% Be leads to partial modification of the Si particles. Full modification was only obtained when Sr was added in an amount of 150–200 ppm, depending on the applied solidification rate. Increasing the amount of Mg to 0.8% in Sr-modified alloys leads to a reduction in the effectiveness of Sr as the main modifier. Similar observations were made when the Fe content was increased in Be-treated alloys due to the Be-Fe interaction. Over-modification results in the precipitation of hard Sr-rich particles, mainly Al4SrSi2, whereas overheating causes incipient melting of the Al-Cu eutectic and hence the surrounding matrix. Both factors lead to a deterioration in the alloy mechanical properties. Furthermore, the presence of long, acicular Si particles accelerates the occurrence of fracture and, as a result, yields poor ductility. In low iron (less than 0.1 wt% Al-Si-Mg alloys, the mechanical properties in the as cast, as well as heat treated conditions, are mainly controlled by the eutectic Si charatersitics. Increasing the iron content and, hence, the volume fraction of Fe-based intermetallics leads to a complex fracture mode.

  18. Electrical Control of g-Factor in a Few-Hole Silicon Nanowire MOSFET.

    Science.gov (United States)

    Voisin, B; Maurand, R; Barraud, S; Vinet, M; Jehl, X; Sanquer, M; Renard, J; De Franceschi, S

    2016-01-13

    Hole spins in silicon represent a promising yet barely explored direction for solid-state quantum computation, possibly combining long spin coherence, resulting from a reduced hyperfine interaction, and fast electrically driven qubit manipulation. Here we show that a silicon-nanowire field-effect transistor based on state-of-the-art silicon-on-insulator technology can be operated as a few-hole quantum dot. A detailed magnetotransport study of the first accessible hole reveals a g-factor with unexpectedly strong anisotropy and gate dependence. We infer that these two characteristics could enable an electrically driven g-tensor-modulation spin resonance with Rabi frequencies exceeding several hundred mega-Hertz.

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

    International Nuclear Information System (INIS)

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

    2010-01-01

    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 7x10 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.

  20. Covalent and stable CuAAC modification of silicon surfaces for control of cell adhesion

    DEFF Research Database (Denmark)

    Vutti, Surendra; Buch-Månson, Nina; Schoffelen, Sanne

    2015-01-01

    in the vapor or liquid phase. In this work, we compared these two methods for oxidized silicon surfaces and thoroughly characterized the functionalization steps by tagging and fluorescence imaging. We demonstrate that the vapor-phase functionalization only provided transient surface modification that was lost...... on extensive washing. For stable surface modification, a liquid-phase method was developed. In this method, silicon wafers were decorated with azides, either by silanization with (3-azidopropyl)triethoxysilane or by conversion of the amine groups of an aminopropylated surface by means of the azido...

  1. Silicon nanodot layers for photovoltaic application: size/density control and electrical properties

    Czech Academy of Sciences Publication Activity Database

    Stegemann, B.; Čermák, Jan; Rezek, Bohuslav; Kočka, Jan; Schmidt, M.

    2014-01-01

    Roč. 228, 4-5 (2014), 543-556 ISSN 0942-9352 R&D Projects: GA MŠk(CZ) LM2011026 Institutional support: RVO:68378271 Keywords : silicon nanodots * Kelvin probe force microscopy * current-sensing AFM * photovoltaic s Subject RIV: BM - Solid Matter Physics ; Magnetism Impact factor: 1.356, year: 2014

  2. Novel silicone compatible cross-linkers for controlled functionalization of PDMS networks

    DEFF Research Database (Denmark)

    Madsen, Frederikke Bahrt; Daugaard, Anders Egede; Hvilsted, Søren

    2013-01-01

    . In order to improve the dielectric properties of PDMS a novel system is developed where push-pull dipoles are grafted to a new silicone compatible cross-linker. The grafted cross-linkers are prepared by reaction of two different push-pull dipole alkynes as well as a fluorescent alkyne with the new azide...

  3. Improved size distribution control of silicon nanocrystals in a spatially confined remote plasma

    NARCIS (Netherlands)

    Dogan, I.; Westerman, R. H. J.; M. C. M. van de Sanden,

    2015-01-01

    This work demonstrates how to improve the size distribution of silicon nanocrystals (Si-NCs) synthesized in a remote plasma, in which the flow dynamics and the particular chemistry initially resulted in the formation of small (2-10 nm) and large (50-120 nm) Si-NCs. Plasma consists of two regions: an

  4. A metamaterial electromagnetic energy rectifying surface with high harvesting efficiency

    Directory of Open Access Journals (Sweden)

    Xin Duan

    2016-12-01

    Full Text Available A novel metamaterial rectifying surface (MRS for electromagnetic energy capture and rectification with high harvesting efficiency is presented. It is fabricated on a three-layer printed circuit board, which comprises an array of periodic metamaterial particles in the shape of mirrored split rings, a metal ground, and integrated rectifiers employing Schottky diodes. Perfect impedance matching is engineered at two interfaces, i.e. one between free space and the surface, and the other between the metamaterial particles and the rectifiers, which are connected through optimally positioned vias. Therefore, the incident electromagnetic power is captured with almost no reflection by the metamaterial particles, then channeled maximally to the rectifiers, and finally converted to direct current efficiently. Moreover, the rectifiers are behind the metal ground, avoiding the disturbance of high power incident electromagnetic waves. Such a MRS working at 2.45 GHz is designed, manufactured and measured, achieving a harvesting efficiency up to 66.9% under an incident power density of 5 mW/cm2, compared with a simulated efficiency of 72.9%. This high harvesting efficiency makes the proposed MRS an effective receiving device in practical microwave power transmission applications.

  5. A metamaterial electromagnetic energy rectifying surface with high harvesting efficiency

    Science.gov (United States)

    Duan, Xin; Chen, Xing; Zhou, Lin

    2016-12-01

    A novel metamaterial rectifying surface (MRS) for electromagnetic energy capture and rectification with high harvesting efficiency is presented. It is fabricated on a three-layer printed circuit board, which comprises an array of periodic metamaterial particles in the shape of mirrored split rings, a metal ground, and integrated rectifiers employing Schottky diodes. Perfect impedance matching is engineered at two interfaces, i.e. one between free space and the surface, and the other between the metamaterial particles and the rectifiers, which are connected through optimally positioned vias. Therefore, the incident electromagnetic power is captured with almost no reflection by the metamaterial particles, then channeled maximally to the rectifiers, and finally converted to direct current efficiently. Moreover, the rectifiers are behind the metal ground, avoiding the disturbance of high power incident electromagnetic waves. Such a MRS working at 2.45 GHz is designed, manufactured and measured, achieving a harvesting efficiency up to 66.9% under an incident power density of 5 mW/cm2, compared with a simulated efficiency of 72.9%. This high harvesting efficiency makes the proposed MRS an effective receiving device in practical microwave power transmission applications.

  6. Bacterial endogenous endophthalmitis in Vietnam: a randomized controlled trial comparing vitrectomy with silicone oil versus vitrectomy alone

    Directory of Open Access Journals (Sweden)

    Do T

    2014-08-01

    Full Text Available Tan Do,1 Do N Hon,1 Tin Aung,2 Nguyen DTN Hien,1 Claude L Cowan Jr3 1Vietnam National Institute of Ophthalmology, Hanoi, Vietnam; 2Singapore National Eye Center, Singapore; 3Georgetown University Medical Center, Washington, DC, USA Background/aims: To compare treatment outcomes with and without silicone oil tamponade in patients undergoing pars plana vitrectomy (PPV for severe endogenous bacterial endophthalmitis (BEE. Methods: One hundred and eight consecutive patients with severe BEE (defined by the absence of pupil red reflex at presentation and/or dense vitreous opacity on ultrasound and no improvement after 24–36 hours of medical treatment were randomly assigned to two treatment groups: Group 1, standard PPV with intravitreal antibiotics; and Group 2, PPV with intravitreal antibiotics and silicone tamponade. Overall success was defined as: a visual acuity ≥ count fingers at 1 meter, with an attached retina, and no intraocular oil. Results: Fifty three patients were randomized to Group 1 and 55 patients to Group 2. The mean age of study subjects was 32 years and baseline clinical characteristics were similar in both groups. At the final follow-up visit at 9 months, the overall success rate of Group 2 (67.3% was significantly better than Group 1 (43.4%; P=0.01. There were also fewer devastating complications (such as inoperable retinal detachment, phthisis bulbi in Group 2 compared with Group 1 (21.8% versus 43.4%; P=0.01. Conclusion: The outcome at 9 months of patients with BEE treated by vitrectomy with silicone oil was better than those treated by vitrectomy alone. Keywords: bacterial endogenous endophthalmitis, vitrectomy, silicone oil endotamponade, randomized controlled trial

  7. A perturbation-based model for rectifier circuits

    Directory of Open Access Journals (Sweden)

    Vipin B. Vats

    2006-01-01

    Full Text Available A perturbation-theoretic analysis of rectifier circuits is presented. The governing differential equation of the half-wave rectifier with capacitor filter is analyzed by expanding the output voltage as a Taylor series with respect to an artificially introduced parameter in the nonlinearity of the diode characteristic as is done in quantum theory. The perturbation parameter introduced in the analysis is independent of the circuit components as compared to the method presented by multiple scales. The various terms appearing in the perturbation series are then modeled in the form of an equivalent circuit. This model is subsequently used in the analysis of full-wave rectifier. Matlab simulation results are included which confirm the validity of the theoretical formulations. Perturbation analysis acts a helpful tool in analyzing time-varying systems and chaotic systems.

  8. High-Fidelity Microwave Control of Single-Atom Spin Qubits in Silicon

    Science.gov (United States)

    2014-07-08

    reality. Every electronic device found in our homes, offices, cars, pockets contains a brain made up of silicon transistors. Naturally, the trillion-dollar...to 6 GHz) and digital IQ modulation. AlazarTech ATS9440 This digitiser samples signals and stores them in memory for analysis, and has a graphical...nanostructures. Spin resonance experiments on donors in enriched 28Si have raised the suspicion that the proximity to a Si/SiO2 interface deteriorates

  9. Property control of graphene aerogels by in situ growth of silicone polymer

    Science.gov (United States)

    Zhou, Shuai; Zhou, Xiang; Hao, Gazi; Jiang, Wei; Wang, Tianhe

    2018-05-01

    Modulation of the density (from 3.5 to 64 mg cm-3), hydrophobicity and oil-uptake capability of graphene aerogels in extensive ranges were achieved by reacting (3-Mercaptopropyl)trimethoxysilane (MPS) with graphene oxide solutions under heating. The reaction allowed a characteristic silicone substructure to be formed on graphene and joint the graphene layers firmly together. With the increase of MPS concentrations (≤ca. 0.2 vol%), the nano silicone polymer grown on graphene functioned as a "linker" and "spacer", leading to a substantial decrease of the aerogel density. Because of the formation of silicone polymer and the characteristic nano-micro substructures on the backbones of graphene aerogels, the graphene aerogels exhibited a high hydrophobicity with the water contact angle consistently exceeding 142 degrees. Functionalized graphene aerogels with a density of 3.5 mg cm-3 were conveniently fabricated that displayed an extraordinary oil absorption capacity, 182 times for lubricating oil and 143 times for n-hexane of its own weight. Furthermore, the aerogels maintained their ultra-high absorption capability even after 20 absorption-distillation cycles, due to structural integrity held by the strong interfacial adhesion between graphene sheets and polymer chains of aerogels. This study offers a promising graphene aerogels and also provides a strategy for fabricating extra low dense functional materials.

  10. Efficacy of the Power Balance Silicone Wristband: a single-blind, randomized, triple placebo-controlled study.

    Science.gov (United States)

    Pothier, David D; Thiel, Gundula; Khoo, S G; Dillon, Wanda A; Sulway, Shaleen; Rutka, John A

    2012-06-01

    The Power Balance Silicone Wristband (Power Balance LLC, Laguna Niguel, CA) (power balance band; PBB) consists of a silicone wristband, incorporating two holograms, which is meant to confer improvements in balance on the wearer. Despite its popularity, the PBB has become somewhat controversial, with a number of articles being published in the news media regarding its efficacy. The PBB has not been formally evaluated but remains popular, largely based on anecdotal evidence. This study subjectively and objectively measured the effects of the PBB on balance in normal participants. A prospective, single-blind, randomized, triple placebo-controlled crossover study was undertaken. Twenty participants underwent measurement using the modified Test of Sensory Interaction on Balance (mCTSIB) and gave subjective feedback (visual analogue scale [VAS]) for each of four band conditions: no band, a silicone band, a deactivated PBB, and the PBB. Participants acted as their own controls. The mean of the four mCTSIB conditions (eyes open and closed on both firm and compliant surfaces) was calculated. This mean value and condition 4 of the mCTSIB were compared between band conditions using path length (PL) and root mean square (RMS) as outcome measures. No significant differences were found between band conditions for PL (p  =  .91 and p  =  .94, respectively) and RMS (p  =  .85 and p  =  .96, respectively). VASs also showed no difference between bands (p  =  .25). The PBB appears to have no effect on mCTSIB or VAS measurements of balance.

  11. Progress in the realization of a silicon-CNT photodetector

    Energy Technology Data Exchange (ETDEWEB)

    Aramo, C., E-mail: aramo@na.infn.it [INFN, Sezione di Napoli, Via Cintia 2, 80126 Napoli (Italy); Ambrosio, A. [CNR-SPIN U.O.S. di Napoli (Italy); Dipartimento di Scienze Fisiche, Universita degli Studi di Napoli Federico II, Via Cintia 2, 80126 Napoli (Italy); Ambrosio, M. [INFN, Sezione di Napoli, Via Cintia 2, 80126 Napoli (Italy); Castrucci, P. [Dipartimento di Fisica, Universita degli Studi di Roma Tor Vergata,Via della Ricerca Scientifica 1, 00133 Roma (Italy); Cilmo, M. [INFN, Sezione di Napoli, Via Cintia 2, 80126 Napoli (Italy); De Crescenzi, M. [Dipartimento di Fisica, Universita degli Studi di Roma Tor Vergata,Via della Ricerca Scientifica 1, 00133 Roma (Italy); Fiandrini, E. [INFN, Sezione di Perugia e Dipartimento di Fisica, Universita degli Studi di Perugia, PiazzaUniversita 1, 06100 Perugia (Italy); Guarino, F. [INFN, Sezione di Napoli, Via Cintia 2, 80126 Napoli (Italy); Dipartimento di Scienze Fisiche, Universita degli Studi di Napoli Federico II, Via Cintia 2, 80126 Napoli (Italy); Grossi, V. [Dipartimento di Fisica, Universita degli Studi dell' Aquila, Via Vetoio 10, 67100 Coppito, L' Aquila (Italy); Nappi, E. [INFN, Sezione di Bari, e Dipartimento di Fisica, Universita degli Studi di Bari, Via Amendola 173, 70126 Bari (Italy); Passacantando, M. [Dipartimento di Fisica, Universita degli Studi dell' Aquila, Via Vetoio 10, 67100 Coppito, L' Aquila (Italy); Pignatel, G. [INFN, Sezione di Perugia e Dipartimento di Fisica, Universita degli Studi di Perugia, PiazzaUniversita 1, 06100 Perugia (Italy); and others

    2012-12-11

    The realization of a Silicon Carbon Nanotube heterojuntion opens the door to a new generation of photodetectors (Si-CNT detector) based on the coupling between this two materials. In particular the growth of Multiwall Carbon Nanotubes on the surface of a n-doped silicon substrate results on a Schottky diode junction with precise rectifying characteristics. The obtained device presents a low dark current, high efficiency in the photoresponsivity, high linearity and a wide stability range. The junction barrier is about 3.5 V in reverse polarity with a breakdown limit at more than 100 V. The spectral behavior reflects the silicon spectral range with a maximum at about 880 nm.

  12. Implementation of a Large Scale Control System for a High-Energy Physics Detector: The CMS Silicon Strip Tracker

    CERN Document Server

    Masetti, Lorenzo; Fischer, Peter

    2011-01-01

    Control systems for modern High-Energy Physics (HEP) detectors are large distributed software systems managing a significant data volume and implementing complex operational procedures. The control software for the LHC experiments at CERN is built on top of a commercial software used in industrial automation. However, HEP specific requirements call for extended functionalities. This thesis focuses on the design and implementation of the control system for the CMS Silicon Strip Tracker but presents some general strategies that have been applied in other contexts. Specific design solutions are developed to ensure acceptable response times and to provide the operator with an effective summary of the status of the devices. Detector safety is guaranteed by proper configuration of independent hardware systems. A software protection mechanism is used to avoid the widespread intervention of the hardware safety and to inhibit dangerous commands. A wizard approach allows non expert operators to recover error situations...

  13. An experimental study on the effects of rectifiers on fluid flow

    International Nuclear Information System (INIS)

    Kawashima, G.

    1985-01-01

    This paper reports studies of various combinations of rectifiers and rectifying nets to measure fluid flow and in particular, the measurement of the flow through an orifice or nozzle, since they help to shorten the inlet length

  14. Depth control of a silicon structure fabricated by 100q keV Ar ion beam lithography

    Energy Technology Data Exchange (ETDEWEB)

    Kawasegi, Noritaka [Graduate School of Science and Engineering, University of Toyama, 3190 Gofuku, Toyama 930-8555 (Japan)]. E-mail: kawasegi@eng.u-toyama.ac.jp; Morita, Noboru [Department of Mechanical and Intellectual Systems Engineering, University of Toyama, 3190 Gofuku, Toyama 930-8555 (Japan)]. E-mail: nmorita@eng.u-toyama.ac.jp; Yamada, Shigeru [Department of Mechanical and Intellectual Systems Engineering, University of Toyama, 3190 Gofuku, Toyama 930-8555 (Japan)]. E-mail: syamada@eng.u-toyama.ac.jp; Takano, Noboru [Department of Mechanical and Intellectual Systems Engineering, University of Toyama, 3190 Gofuku, Toyama 930-8555 (Japan)]. E-mail: takano@eng.u-toyama.ac.jp; Oyama, Tatsuo [Department of Mechanical and Intellectual Systems Engineering, University of Toyama, 3190 Gofuku, Toyama 930-8555 (Japan)]. E-mail: ohyama@eng.u-toyama.ac.jp; Momota, Sadao [Department of Intelligent Mechanical Systems Engineering, Kochi University of Technology, 185 Tosayamada, Kami, Kochi 782-8502 (Japan)]. E-mail: momota.sadao@kochi-tech.ac.jp; Taniguchi, Jun [Department of Applied Electronics, Tokyo University of Science, 2641 Yamazaki, Noda, Chiba 278-8510 (Japan)]. E-mail: junt@te.noda.tus.ac.jp; Miyamoto, Iwao [Department of Applied Electronics, Tokyo University of Science, 2641 Yamazaki, Noda, Chiba 278-8510 (Japan)]. E-mail: iwao@te.noda.tus.ac.jp

    2007-01-15

    Ion beam lithography of a silicon surface using an Ar ion beam with an ion energy in the order of hundreds of keV is demonstrated in this study. A specially designed ion irradiation facility was employed that enabled generation and irradiation with a highly accelerated and highly charged Ar ion beam. An ion-beam-induced amorphous layer on a silicon substrate can be selectively etched in hydrofluoric acid, whereas, a non-irradiated area is scarcely etched and, consequently, a concave structure can be fabricated on the irradiated area. To control the depth of the structure, parameters for dependence of the depth on ion irradiation were investigated. As a result, the depth of irradiated area can be controlled by the ion energy that is adjusted by the acceleration voltage and the ion charge. In addition, the etch resistance of the irradiated area increases with an increase in ion energy due to the crystalline layer formed on the surface. Simulation results reveal that the depth is strongly related to the defect distribution induced by ion irradiation. These results indicate the potential use of this method for novel three-dimensional lithography.

  15. Rectifier analysis for radio frequency energy harvesting and power transport

    NARCIS (Netherlands)

    Keyrouz, S.; Visser, H.J.; Tijhuis, A.G.

    2012-01-01

    Wireless Power Transmission (WPT) is an attractive powering method for wireless sensor nodes, battery-less sensors, and Radio-Frequency Identification (RFID) tags. The key element on the receiving side of a WPT system is the rectifying antenna (rectenna) which captures the electromagnetic power and

  16. A thermally switched 9 kA superconducting rectifier fluxpump

    NARCIS (Netherlands)

    ten Kate, Herman H.J.; Bunk, Paul B.; Steffens, Harry A.; van de Klundert, Louis J.M.

    1981-01-01

    The feasibility of superconducting rectifier-fluxpumps has to be demonstrated at current levels of 10 - 100 kA, where is asked for in the superconducting devices now being planned. An intensive program has been started at the low temperature division of the University of Twente to construct such

  17. Frequency Support from OWPPs connected to HVDC via Diode Rectifiers

    DEFF Research Database (Denmark)

    Saborío-Romano, Oscar; Bidadfar, Ali; Göksu, Ömer

    This paper presents a study assessing the actual capability of an offshore wind power plant (offshore WPP, OWPP) to provide frequency support (FS) to an onshore network, when connected through a high-voltage direct-current (HVDC) link having a diode rectifier (DR) offshore terminal and a voltage...

  18. Rectified heat transfer into translating and pulsating vapor bubbles

    NARCIS (Netherlands)

    Hao, Y.; Prosperetti, Andrea

    2002-01-01

    It is well known that, when a stationary vapor bubble is subject to a sufficiently intense acoustic field, it will grow by rectified heat transfer even in a subcooled liquid. The object of this paper is to study how translation, and the ensuing convective effects, influence this process. It is shown

  19. Plasma monitoring and PECVD process control in thin film silicon-based solar cell manufacturing

    Directory of Open Access Journals (Sweden)

    Gabriel Onno

    2014-02-01

    Full Text Available A key process in thin film silicon-based solar cell manufacturing is plasma enhanced chemical vapor deposition (PECVD of the active layers. The deposition process can be monitored in situ by plasma diagnostics. Three types of complementary diagnostics, namely optical emission spectroscopy, mass spectrometry and non-linear extended electron dynamics are applied to an industrial-type PECVD reactor. We investigated the influence of substrate and chamber wall temperature and chamber history on the PECVD process. The impact of chamber wall conditioning on the solar cell performance is demonstrated.

  20. Wavelength-controlled external-cavity laser with a silicon photonic crystal resonant reflector

    Science.gov (United States)

    Gonzalez-Fernandez, A. A.; Liles, Alexandros A.; Persheyev, Saydulla; Debnath, Kapil; O'Faolain, Liam

    2016-03-01

    We report the experimental demonstration of an alternative design of external-cavity hybrid lasers consisting of a III-V Semiconductor Optical Amplifier with fiber reflector and a Photonic Crystal (PhC) based resonant reflector on SOI. The Silicon reflector comprises a polymer (SU8) bus waveguide vertically coupled to a PhC cavity and provides a wavelength-selective optical feedback to the laser cavity. This device exhibits milliwatt-level output power and sidemode suppression ratio of more than 25 dB.

  1. Test and commissioning of the CARLOS control boards for the ALICE Silicon Drift Detectors

    CERN Document Server

    Alessandro, Bruno; Beolè, S; Coli, S; Costa, F; De Remigis, P; Falchieri, Davide; Gandolfi, Enzo; Giraudo, G; Giubellino, P; Kral, J F; Masetti, Massimo; Mazza, G; Rashevsky, A; Riccati, Lodovico; Rivetti, A; Senyukov, S; Toscano, Letterio; Tosello, F; Wheadon, R

    2007-01-01

    This paper presents the test strategy employed during the installation of the CARLOS end ladder boards developed for the Silicon Drift Detectors (SDD) of ALICE. Each CARLOS board compresses the data provided by the front-end electronics of one SDD and sends them via an optical link of 800 Mbit/s to the data concentrator card (CARLOSrx) located in the counting room. The paper describes the integration of the CARLOS boards in the final SDD system, including its cooling and mechanical support, the power supply distribution and the optical interconnections. The results of the tests performed after each step of the installation sequence are reported.

  2. Junction barrier Schottky rectifier with an improved P-well region

    International Nuclear Information System (INIS)

    Wang Ying; Li Ting; Cao Fei; Shao Lei; Chen Yu-Xian

    2012-01-01

    A junction barrier Schottky (JBS) rectifier with an improved P-well on 4H—SiC is proposed to improve the V F —I R trade-off and the breakdown voltage. The reverse current density of the proposed JBS rectifier at 300 K and 800 V is about 3.3×10 −8 times that of the common JBS rectifier at no expense of the forward voltage drop. This is because the depletion layer thickness in the P-well region at the same reverse voltage is larger than in the P + grid, resulting in a lower spreading current and tunneling current. As a result, the breakdown voltage of the proposed JBS rectifier is over 1.6 kV, that is about 0.8 times more than that of the common JBS rectifier due to the uniform electric field. Although the series resistance of the proposed JBS rectifier is a little larger than that of the common JBS rectifier, the figure of merit (FOM) of the proposed JBS rectifier is about 2.9 times that of the common JBS rectifier. Based on simulating the values of susceptibility of the two JBS rectifiers to electrostatic discharge (ESD) in the human body model (HBM) circuits, the failure energy of the proposed JBS rectifier increases 17% compared with that of the common JBS rectifier. (interdisciplinary physics and related areas of science and technology)

  3. Thermal analysis and improvement of cascode GaN device package for totem-pole bridgeless PFC rectifier

    International Nuclear Information System (INIS)

    She, Shuojie; Zhang, Wenli; Liu, Zhengyang; Lee, Fred C.; Huang, Xiucheng; Du, Weijing; Li, Qiang

    2015-01-01

    The totem-pole bridgeless power factor correction (PFC) rectifier has a simpler topology and higher efficiency than other boost-type bridgeless PFC rectifiers. Its promising performance is enabled by using high-voltage gallium nitride (GaN) high-electron-mobility transistors, which have considerably better figures of merit (e.g., lower reverse recovery charges and less switching losses) than the state-of-the-art silicon metal-oxide-semiconductor field-effect transistors. Cascode GaN devices in traditional packages, i.e., the TO-220 and power quad flat no-lead, are used in the totem-pole PFC boost rectifier. But the parasitic inductances induced by the traditional packages not only significantly deteriorate the switching characteristics of the discrete GaN device but also adversely affect the performance of the built PFC rectifier. A new stack-die packaging structure with an embedded capacitor has been introduced and proven to be efficient in reducing parasitic ringing at the turn-off transition and achieving true zero-voltage-switching turn-on. However, the thermal dissipation capability of the device packaged in this configuration becomes a limitation on further pushing the operating frequency and the output current level for high-efficiency power conversion. This paper focuses on the thermal analysis of the cascode GaN devices in different packages and the GaN-based multichip module used in a two-phase totem-pole bridgeless PFC boost rectifier. A series of thermal models are built based on the actual structures and materials of the packaged devices to evaluate their thermal performance. Finite element analysis (FEA) simulation results of the cascode GaN device in a flip-chip format demonstrate the possibility of increasing the device switching speed while maintaining the peak temperature of the device below 125 °C. Thermal analysis of the GaN-based power module in a very similar structure is also conducted using the FEA method. Experimental data measured using

  4. Investigation of a combined platinum and electron lifetime control treatment for silicon

    International Nuclear Information System (INIS)

    Jia, Yunpeng; Cui, Zhihang; Yang, Fei; Zhao, Bao; Zou, Shikai; Liang, Yongsheng

    2017-01-01

    In silicon, the effect of Combined Lifetime Treatment (CLT) involving platinum diffusion and subsequent electron irradiation is different from the separate treatments of platinum diffusion and electron irradiation, even the treatment of electron irradiation followed by platinum diffusion. In this paper, we investigated the experimental behavior of different kinds of lifetime treated samples. We found that the reverse leakage current (I rr ) increases with the increasing platinum diffusion temperature or electron irradiation dose in the separate treatments. Conversely, I rr of the CLT samples decreased with rising platinum diffusion temperature at the same dose of subsequent electron irradiation. By deep-level transient spectroscopy (DLTS), a new energy level E7 (Ec −0.376 eV) was found in our CLT samples. The new level E7 suppresses the dominance of the deeper level E8 (Ec −0.476 eV), which is caused by electron irradiation directly and results in I rr ’s increase. The formation of the level E7 comes from the complex defect-combined effect between platinum atoms and silicon vacancies, and it affects device’s characteristics finally. These research will be helpful to the development of platinum-diffused devices used in intense electron irradiation environments.

  5. Investigation of a combined platinum and electron lifetime control treatment for silicon

    Energy Technology Data Exchange (ETDEWEB)

    Jia, Yunpeng [College of Electronic Information and Control Engineering, Beijing University of Technology, Beijing 100124 (China); Cui, Zhihang, E-mail: czhczh321321@126.com [College of Electronic Information and Control Engineering, Beijing University of Technology, Beijing 100124 (China); Yang, Fei [State Grid Smart Electrical Engineering, Beijing 100192 (China); Zhao, Bao; Zou, Shikai; Liang, Yongsheng [College of Electronic Information and Control Engineering, Beijing University of Technology, Beijing 100124 (China)

    2017-02-01

    In silicon, the effect of Combined Lifetime Treatment (CLT) involving platinum diffusion and subsequent electron irradiation is different from the separate treatments of platinum diffusion and electron irradiation, even the treatment of electron irradiation followed by platinum diffusion. In this paper, we investigated the experimental behavior of different kinds of lifetime treated samples. We found that the reverse leakage current (I{sub rr}) increases with the increasing platinum diffusion temperature or electron irradiation dose in the separate treatments. Conversely, I{sub rr} of the CLT samples decreased with rising platinum diffusion temperature at the same dose of subsequent electron irradiation. By deep-level transient spectroscopy (DLTS), a new energy level E7 (Ec −0.376 eV) was found in our CLT samples. The new level E7 suppresses the dominance of the deeper level E8 (Ec −0.476 eV), which is caused by electron irradiation directly and results in I{sub rr}’s increase. The formation of the level E7 comes from the complex defect-combined effect between platinum atoms and silicon vacancies, and it affects device’s characteristics finally. These research will be helpful to the development of platinum-diffused devices used in intense electron irradiation environments.

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

    International Nuclear Information System (INIS)

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

    2012-01-01

    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. (paper)

  7. Silicon detectors

    International Nuclear Information System (INIS)

    Klanner, R.

    1984-08-01

    The status and recent progress of silicon detectors for high energy physics is reviewed. Emphasis is put on detectors with high spatial resolution and the use of silicon detectors in calorimeters. (orig.)

  8. A 13.56 MHz CMOS Active Rectifier With Switched-Offset and Compensated Biasing for Biomedical Wireless Power Transfer Systems.

    Science.gov (United States)

    Yan Lu; Wing-Hung Ki

    2014-06-01

    A full-wave active rectifier switching at 13.56 MHz with compensated bias current for a wide input range for wirelessly powered high-current biomedical implants is presented. The four diodes of a conventional passive rectifier are replaced by two cross-coupled PMOS transistors and two comparator- controlled NMOS switches to eliminate diode voltage drops such that high voltage conversion ratio and power conversion efficiency could be achieved even at low AC input amplitude |VAC|. The comparators are implemented with switched-offset biasing to compensate for the delays of active diodes and to eliminate multiple pulsing and reverse current. The proposed rectifier uses a modified CMOS peaking current source with bias current that is quasi-inversely proportional to the supply voltage to better control the reverse current over a wide AC input range (1.5 to 4 V). The rectifier was fabricated in a standard 0.35 μm CMOS N-well process with active area of 0.0651 mm(2). For the proposed rectifier measured at |VAC| = 3.0 V, the voltage conversion ratios are 0.89 and 0.93 for RL=500 Ω and 5 kΩ, respectively, and the measured power conversion efficiencies are 82.2% to 90.1% with |VAC| ranges from 1.5 to 4 V for RL=500 Ω.

  9. Thermally controlled coupling of a rolled-up microtube integrated with a waveguide on a silicon electronic-photonic integrated circuit.

    Science.gov (United States)

    Zhong, Qiuhang; Tian, Zhaobing; Veerasubramanian, Venkat; Dastjerdi, M Hadi Tavakoli; Mi, Zetian; Plant, David V

    2014-05-01

    We report on the first experimental demonstration of the thermal control of coupling strength between a rolled-up microtube and a waveguide on a silicon electronic-photonic integrated circuit. The microtubes are fabricated by selectively releasing a coherently strained GaAs/InGaAs heterostructure bilayer. The fabricated microtubes are then integrated with silicon waveguides using an abruptly tapered fiber probe. By tuning the gap between the microtube and the waveguide using localized heaters, the microtube-waveguide evanescent coupling is effectively controlled. With heating, the extinction ratio of a microtube whispering-gallery mode changes over an 18 dB range, while the resonant wavelength remains approximately unchanged. Utilizing this dynamic thermal tuning effect, we realize coupling modulation of the microtube integrated with the silicon waveguide at 2 kHz with a heater voltage swing of 0-6 V.

  10. Control of the optical properties of silicon and chromium mixed oxides deposited by reactive magnetron sputtering

    International Nuclear Information System (INIS)

    Vergara, L.; Galindo, R. Escobar; Martinez, R.; Sanchez, O.; Palacio, C.; Albella, J.M.

    2011-01-01

    The development of mixed-oxide thin films allows obtaining materials with better properties than those of the different binary oxides, which makes them suitable for a great number of applications in different fields, such as tribology, optics or microelectronics. In this paper we investigate the deposition of mixed chromium and silicon oxides deposited by reactive magnetron sputtering with a view to use them as optical coatings with an adjustable refractive index. These films have been characterized by means of Rutherford backscattering spectrometry, Auger electron spectroscopy, X-ray diffraction, scanning electron microscopy, Fourier-transform infrared spectroscopy and spectroscopic ellipsometry so as to determine how the deposition conditions influence the characteristics of the material. We have found that the deposition parameter whose influence determines the properties of the films to a greater extent is the amount of oxygen in the reactive sputtering gas.

  11. Organic Vapour Sensing Properties of Area-Ordered and Size-Controlled Silicon Nanopillar

    Directory of Open Access Journals (Sweden)

    Wei Li

    2016-11-01

    Full Text Available Here, a silicon nanopillar array (Si-NPA was fabricated. It was studied as a room-temperature organic vapour sensor, and the ethanol and acetone gas sensing properties were detected with I-V curves. I-V curves show that these Si-NPA gas sensors are sensitive to ethanol and acetone organic vapours. The turn-on threshold voltage is about 0.5 V and the operating voltage is 3 V. With 1% ethanol gas vapour, the response time is 5 s, and the recovery time is 15 s. Furthermore, an evaluation of the gas sensor stability for Si-NPA was performed. The gas stability results are acceptable for practical detections. These excellent sensing characteristics can mainly be attributed to the change of the overall dielectric constant of Si-NPA caused by the physisorption of gas molecules on the pillars, and the filling of the gas vapour in the voids.

  12. Periodically poled silicon

    Science.gov (United States)

    Hon, Nick K.; Tsia, Kevin K.; Solli, Daniel R.; Khurgin, Jacob B.; Jalali, Bahram

    2010-02-01

    Bulk centrosymmetric silicon lacks second-order optical nonlinearity χ(2) - a foundational component of nonlinear optics. Here, we propose a new class of photonic device which enables χ(2) as well as quasi-phase matching based on periodic stress fields in silicon - periodically-poled silicon (PePSi). This concept adds the periodic poling capability to silicon photonics, and allows the excellent crystal quality and advanced manufacturing capabilities of silicon to be harnessed for devices based on χ(2)) effects. The concept can also be simply achieved by having periodic arrangement of stressed thin films along a silicon waveguide. As an example of the utility, we present simulations showing that mid-wave infrared radiation can be efficiently generated through difference frequency generation from near-infrared with a conversion efficiency of 50% based on χ(2) values measurements for strained silicon reported in the literature [Jacobson et al. Nature 441, 199 (2006)]. The use of PePSi for frequency conversion can also be extended to terahertz generation. With integrated piezoelectric material, dynamically control of χ(2)nonlinearity in PePSi waveguide may also be achieved. The successful realization of PePSi based devices depends on the strength of the stress induced χ(2) in silicon. Presently, there exists a significant discrepancy in the literature between the theoretical and experimentally measured values. We present a simple theoretical model that produces result consistent with prior theoretical works and use this model to identify possible reasons for this discrepancy.

  13. Development of Op-Amp Based Piezoelectric Rectifier for Low Power Energy Harvesting Applications

    Directory of Open Access Journals (Sweden)

    Syazmie Bin Sepeeh Muhamad

    2018-01-01

    Full Text Available In this study, the development of operational amplifier (op-amp based rectifier for piezoelectric energy harvesting applications was studied. The two stage op-amp full wave rectifier was used to convert the AC signal to DC signal voltage received by piezoelectric devices. The inverted half wave rectifier integrated with full wave rectifier were designed and simulated using MultiSIM software. The circuit was then fabricated onto a printed circuit board (PCB, using standard fabrication process. The achievement of this rectifier was able to boost up the maximum voltage of 5 V for input voltage of 800 mV. The output of the rectifier was in DC signal after the rectification by the op-amp. In term of power, the power dissipation was reduced consequently the waste power decreases. Future work includes optimization of the rectifying circuit to operate more efficiently can be made to increase the efficiency of the devices.

  14. Semiconductor-metal phase transition of vanadium dioxide nanostructures on silicon substrate: Applications for thermal control of spacecraft

    International Nuclear Information System (INIS)

    Leahu, G. L.; Li Voti, R.; Larciprete, M. C.; Belardini, A.; Mura, F.; Sibilia, C.; Bertolotti, M.; Fratoddi, I.

    2013-01-01

    We present a detailed infrared study of the semiconductor-to-metal transition (SMT) in a vanadium dioxide (VO2) film deposited on silicon wafer. The VO2 phase transition is studied in the mid-infrared (MIR) region by analyzing the transmittance and the reflectance measurements, and the calculated emissivity. The temperature behaviour of the emissivity during the SMT put into evidence the phenomenon of the anomalous absorption in VO2 which has been explained by applying the Maxwell Garnett effective medium approximation theory, together with a strong hysteresis phenomenon, both useful to design tunable thermal devices to be applied for the thermal control of spacecraft. We have also applied the photothermal radiometry in order to study the changes in the modulated emissivity induced by laser. Experimental results show how the use of these techniques represent a good tool for a quantitative measurement of the optothermal properties of vanadium dioxide based structures

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

    Energy Technology Data Exchange (ETDEWEB)

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

    2014-01-01

    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.

  16. Performance evaluation of a rectifier column using gamma column scanning

    Directory of Open Access Journals (Sweden)

    Aquino Denis D.

    2017-12-01

    Full Text Available Rectifier columns are considered to be a critical component in petroleum refineries and petrochemical processing installations as they are able to affect the overall performance of these facilities. It is deemed necessary to monitor the operational conditions of such vessels to optimize processes and prevent anomalies which could pose undesired consequences on product quality that might lead to huge financial losses. A rectifier column was subjected to gamma scanning using a 10-mCi Co-60 source and a 2-inch-long detector in tandem. Several scans were performed to gather information on the operating conditions of the column under different sets of operating parameters. The scan profiles revealed unexpected decreases in the radiation intensity at vapour levels between trays 2 and 3, and between trays 4 and 5. Flooding also occurred during several scans which could be attributed to parametric settings.

  17. Silicon microfluidic flow focusing devices for the production of size-controlled PLGA based drug loaded microparticles.

    Science.gov (United States)

    Keohane, Kieran; Brennan, Des; Galvin, Paul; Griffin, Brendan T

    2014-06-05

    The increasing realisation of the impact of size and surface properties on the bio-distribution of drug loaded colloidal particles has driven the application of micro fabrication technologies for the precise engineering of drug loaded microparticles. This paper demonstrates an alternative approach for producing size controlled drug loaded PLGA based microparticles using silicon Microfluidic Flow Focusing Devices (MFFDs). Based on the precise geometry and dimensions of the flow focusing channel, microparticle size was successfully optimised by modifying the polymer type, disperse phase (Qd) flow rate, and continuous phase (Qc) flow rate. The microparticles produced ranged in sizes from 5 to 50 μm and were highly monodisperse (coefficient of variation <5%). A comparison of Ciclosporin (CsA) loaded PLGA microparticles produced by MFFDs vs conventional production techniques was also performed. MFFDs produced microparticles with a narrower size distribution profile, relative to the conventional approaches. In-vitro release kinetics of CsA was found to be influenced by the production technique, with the MFFD approach demonstrating the slowest rate of release over 7 days (4.99 ± 0.26%). Finally, MFFDs were utilised to produce pegylated microparticles using the block co-polymer, PEG-PLGA. In contrast to the smooth microparticles produced using PLGA, PEG-PLGA microparticles displayed a highly porous surface morphology and rapid CsA release, with 85 ± 6.68% CsA released after 24h. The findings from this study demonstrate the utility of silicon MFFDs for the precise control of size and surface morphology of PLGA based microparticles with potential drug delivery applications. Copyright © 2014 Elsevier B.V. All rights reserved.

  18. Spatial fluctuations in barrier height at the graphene-silicon carbide Schottky junction.

    Science.gov (United States)

    Rajput, S; Chen, M X; Liu, Y; Li, Y Y; Weinert, M; Li, L

    2013-01-01

    When graphene is interfaced with a semiconductor, a Schottky contact forms with rectifying properties. Graphene, however, is also susceptible to the formation of ripples upon making contact with another material. Here we report intrinsic ripple- and electric field-induced effects at the graphene semiconductor Schottky junction, by comparing chemical vapour-deposited graphene transferred on semiconductor surfaces of opposite polarization-the hydrogen-terminated silicon and carbon faces of hexagonal silicon carbide. Using scanning tunnelling microscopy/spectroscopy and first-principles calculations, we show the formation of a narrow Schottky dipole barrier approximately 10 Å wide, which facilitates the observed effective electric field control of the Schottky barrier height. We further find atomic-scale spatial fluctuations in the Schottky barrier that directly follow the undulation of ripples on both graphene-silicon carbide junctions. These findings reveal fundamental properties of the graphene/semiconductor Schottky junction-a key component of vertical graphene devices that offer functionalities unattainable in planar device architecture.

  19. Fast switching wideband rectifying circuit for future RF energy harvesting

    Science.gov (United States)

    Asmeida, Akrem; Mustam, Saizalmursidi Md; Abidin, Z. Z.; Ashyap, A. Y. I.

    2017-09-01

    This paper presents the design and simulation of fast switching microwave rectifying circuit for ultra wideband patch antenna over a dual-frequency band (1.8 GHz for GSM and 2.4 GHz for ISM band). This band was chosen due to its high signal availability in the surrounding environment. New rectifying circuit topology with pair-matching trunks is designed using Advanced Design System (ADS) software. These trunks are interfaced with power divider to achieve good bandwidth, fast switching and high efficiency. The power divider acts as a good isolator between the trunks and its straightforward design structure makes it a good choice for a single feed UWB antenna. The simulated results demonstrate that the maximum output voltage is 2.13 V with an input power of -5 dBm. Moreover, the rectifier offers maximum efficiency of 86% for the input power of -5 dBm at given band, which could easily power up wireless sensor networks (WSN) and other small devices sufficiently.

  20. Magnetic flow control in growth and casting of photovoltaic silicon: Numerical and experimental results

    Science.gov (United States)

    Poklad, A.; Pal, J.; Galindo, V.; Grants, I.; Heinze, V.; Meier, D.; Pätzold, O.; Stelter, M.; Gerbeth, G.

    2017-07-01

    A novel, vertical Bridgman-type technique for growing multi-crystalline silicon ingots in an induction furnace is described. In contrast to conventional growth, a modified setup with a cone-shaped crucible and susceptor is used. A detailed numerical simulation of the setup is presented. It includes a global thermal simulation of the furnace and a local simulation of the melt, which aims at the influence of the melt flow on the temperature and concentration fields. Furthermore, seeded growth of cone-shaped Si ingots using either a monocrystalline seed or a seed layer formed by pieces of poly-Si is demonstrated and compared to growth without seeds. The influences of the seed material on the grain structure and the dislocation density of the ingots are discussed. The second part addresses model experiments for the Czochralski technique using the room temperature liquid metal GaInSn. The studies were focused on the influence of a rotating and a horizontally static magnetic field on the melt flow and the related heat transport in crucibles being heated from bottom and/or side, and cooled by a crystal model covering about 1/3 of the upper melt surface.

  1. Kinetics and fracture resistance of lithiated silicon nanostructure pairs controlled by their mechanical interaction

    Energy Technology Data Exchange (ETDEWEB)

    Lee, Seok Woo; /Stanford U., Geballe Lab.; Lee, Hyun-Wook; /Stanford U., Materials Sci. Dept.; Ryu, Ill; /Brown U.; Nix, William D.; /Stanford U., Materials Sci. Dept.; Gao, Huajian; /Brown U.; Cui, Yi; /Stanford U., Materials Sci. Dept. /SLAC

    2015-06-01

    Following an explosion of studies of silicon as a negative electrode for Li-ion batteries, the anomalous volumetric changes and fracture of lithiated single Si particles have attracted significant attention in various fields, including mechanics. However, in real batteries, lithiation occurs simultaneously in clusters of Si in a confined medium. Hence, understanding how the individual Si structures interact during lithiation in a closed space is necessary. Herein, we demonstrate physical/mechanical interactions of swelling Si structures during lithiation using well-defined Si nanopillar pairs. Ex situ SEM and in situ TEM studies reveal that compressive stresses change the reaction kinetics so that preferential lithiation occurs at free surfaces when the pillars are mechanically clamped. Such mechanical interactions enhance the fracture resistance of This material is based upon work supported by the U.S. Department of Energy, Office of Science, Office of Basic Energy Sciences, Division of Materials Sciences and Engineering, under Contract No. DE-AC02-76SF00515. SLAC-PUB-16300 2 lithiated Si by lessening the tensile stress concentrations in Si structures. This study will contribute to improved design of Si structures at the electrode level for high performance Li-ion batteries.

  2. Prolonged controlled delivery of nerve growth factor using porous silicon nanostructures.

    Science.gov (United States)

    Zilony, Neta; Rosenberg, Michal; Holtzman, Liran; Schori, Hadas; Shefi, Orit; Segal, Ester

    2017-07-10

    Although nerve growth factor (NGF) is beneficial for the treatment of numerous neurological and non-neurological diseases, its therapeutic administration represents a significant challenge, due to the difficulty to locally deliver relevant doses in a safe and non-invasive manner. In this work, we employ degradable nanostructured porous silicon (PSi) films as carriers for NGF, allowing its continuous and prolonged release, while retaining its bioactivity. The PSi carriers exhibit high loading efficacy (up to 90%) of NGF and a continuous release, with no burst, over a period of>26days. The released NGF bioactivity is compared to that of free NGF in both PC12 cells and dissociated dorsal root ganglion (DRG) neurons. We show that the NGF has retained its bioactivity and induces neurite outgrowth and profound differentiation (of >50% for PC12 cells) throughout the period of release within a single administration. Thus, this proof-of-concept study demonstrates the immense therapeutic potential of these tunable carriers as long-term implants of NGF reservoirs and paves the way for new localized treatment strategies of neurodegenerative diseases. Copyright © 2016 Elsevier B.V. All rights reserved.

  3. Glass frit bonding with controlled width and height using a two-step wet silicon etching procedure

    Science.gov (United States)

    Yifang, Liu; Daner, Chen; Liwei, Lin; Gaofeng, Zheng; Jianyi, Zheng; Lingyun, Wang; Daoheng, Sun

    2016-03-01

    A simple and versatile two-step silicon wet etching technique for the control of the width and height of the glass frit bonding layer has been developed to improve bonding strength and reliability in wafer-level microelectromechanical systems (MEMS) packaging processes. The height of the glass frit bonding layer is set by the design of a vertical reference wall which regulates the distance between the silicon wafer and the encapsulation capping substrate. On the other hand, the width of the bonding layer is constrained between two micro grooves which are used to accommodate the spillages of extra glass frit during the bonding process. An optimized thermal bonding process, including the formation of glass liquid, removal of gas bubbles under vacuum and the filling of voids under normal atmospheric condition has been developed to suppress the formation of the bubbles/voids. The stencil printing and pre-sintering processes for the glass frit have been characterized before the thermal bonding process under different magnitudes of bonding pressure. The bonding gap thickness is found to be equal to the height of the reference wall of 10 μm in the prototype design. The bubbles/voids are found to be suppressed effectively and the bonding strength increases from 10.2 to 19.1 MPa as compared with a conventional thermal annealing process in air. Experimentally, prototype samples are measured to have passed the high hermetic sealing leakage tests of 5  ×  10-8 atm cc s-1.

  4. RF rectifiers for EM power harvesting in a Deep Brain Stimulating device.

    Science.gov (United States)

    Hosain, Md Kamal; Kouzani, Abbas Z; Tye, Susannah; Kaynak, Akif; Berk, Michael

    2015-03-01

    A passive deep brain stimulation (DBS) device can be equipped with a rectenna, consisting of an antenna and a rectifier, to harvest energy from electromagnetic fields for its operation. This paper presents optimization of radio frequency rectifier circuits for wireless energy harvesting in a passive head-mountable DBS device. The aim is to achieve a compact size, high conversion efficiency, and high output voltage rectifier. Four different rectifiers based on the Delon doubler, Greinacher voltage tripler, Delon voltage quadrupler, and 2-stage charge pumped architectures are designed, simulated, fabricated, and evaluated. The design and simulation are conducted using Agilent Genesys at operating frequency of 915 MHz. A dielectric substrate of FR-4 with thickness of 1.6 mm, and surface mount devices (SMD) components are used to fabricate the designed rectifiers. The performance of the fabricated rectifiers is evaluated using a 915 MHz radio frequency (RF) energy source. The maximum measured conversion efficiency of the Delon doubler, Greinacher tripler, Delon quadrupler, and 2-stage charge pumped rectifiers are 78, 75, 73, and 76 % at -5 dBm input power and for load resistances of 5-15 kΩ. The conversion efficiency of the rectifiers decreases significantly with the increase in the input power level. The Delon doubler rectifier provides the highest efficiency at both -5 and 5 dBm input power levels, whereas the Delon quadrupler rectifier gives the lowest efficiency for the same inputs. By considering both efficiency and DC output voltage, the charge pump rectifier outperforms the other three rectifiers. Accordingly, the optimised 2-stage charge pumped rectifier is used together with an antenna to harvest energy in our DBS device.

  5. Formation of porous silicon oxide from substrate-bound silicon rich silicon oxide layers by continuous-wave laser irradiation

    Science.gov (United States)

    Wang, Nan; Fricke-Begemann, Th.; Peretzki, P.; Ihlemann, J.; Seibt, M.

    2018-03-01

    Silicon nanocrystals embedded in silicon oxide that show room temperature photoluminescence (PL) have great potential in silicon light emission applications. Nanocrystalline silicon particle formation by laser irradiation has the unique advantage of spatially controlled heating, which is compatible with modern silicon micro-fabrication technology. In this paper, we employ continuous wave laser irradiation to decompose substrate-bound silicon-rich silicon oxide films into crystalline silicon particles and silicon dioxide. The resulting microstructure is studied using transmission electron microscopy techniques with considerable emphasis on the formation and properties of laser damaged regions which typically quench room temperature PL from the nanoparticles. It is shown that such regions consist of an amorphous matrix with a composition similar to silicon dioxide which contains some nanometric silicon particles in addition to pores. A mechanism referred to as "selective silicon ablation" is proposed which consistently explains the experimental observations. Implications for the damage-free laser decomposition of silicon-rich silicon oxides and also for controlled production of porous silicon dioxide films are discussed.

  6. Control of periodic surface structures on silicon by combined temporal and polarization shaping of femtosecond laser pulses

    Science.gov (United States)

    Fraggelakis, F.; Stratakis, E.; Loukakos, P. A.

    2018-06-01

    We demonstrate the capability to exercise advanced control on the laser-induced periodic surface structures (LIPSS) on silicon by combining the effect of temporal shaping, via tuning the interpulse temporal delay between double femtosecond laser pulses, along with the independent manipulation of the polarization state of each of the individual pulses. For this, cross-polarized (CP) as well as counter-rotating (CR) double circularly polarized pulses have been utilized. The pulse duration was 40 fs and the central wavelength of 790 nm. The linearly polarized double pulses are generated by a modified Michelson interferometer allowing the temporal delay between the pulses to vary from Δτ = -80 ps to Δτ = +80 ps with an accuracy of 0.2 fs. We show the significance of fluence balance between the two pulse components and its interplay with the interpulse delay and with the order of arrival of the individually polarized pulse components of the double pulse sequence on the final surface morphology. For the case of CR pulses we found that when the pulses are temporally well separated the surface morphology attains no axial symmetry. But strikingly, when the two CP pulses temporally overlap, we demonstrate, for the first time in our knowledge, the detrimental effect that the phase delay has on the ripple orientation. Our results provide new insight showing that temporal pulse shaping in combination with polarization control gives a powerful tool for drastically controlling the surface nanostructure morphology.

  7. Microfluidic assisted one-step fabrication of porous silicon@acetalated dextran nanocomposites for precisely controlled combination chemotherapy.

    Science.gov (United States)

    Liu, Dongfei; Zhang, Hongbo; Mäkilä, Ermei; Fan, Jin; Herranz-Blanco, Bárbara; Wang, Chang-Fang; Rosa, Ricardo; Ribeiro, António J; Salonen, Jarno; Hirvonen, Jouni; Santos, Hélder A

    2015-01-01

    An advanced nanocomposite consisting of an encapsulated porous silicon (PSi) nanoparticle and an acid-degradable acetalated dextran (AcDX) matrix (nano-in-nano), was efficiently fabricated by a one-step microfluidic self-assembly approach. The obtained nano-in-nano PSi@AcDX composites showed improved surface smoothness, homogeneous size distribution, and considerably enhanced cytocompatibility. Furthermore, multiple drugs with different physicochemical properties have been simultaneously loaded into the nanocomposites with a ratiometric control. The release kinetics of all the payloads was predominantly controlled by the decomposition rate of the outer AcDX matrix. To facilitate the intracellular drug delivery, a nona-arginine cell-penetrating peptide (CPP) was chemically conjugated onto the surface of the nanocomposites by oxime click chemistry. Taking advantage of the significantly improved cell uptake, the proliferation of two breast cancer cell lines was markedly inhibited by the CPP-functionalized multidrug-loaded nanocomposites. Overall, this nano-in-nano PSi@polymer composite prepared by the microfluidic self-assembly approach is a universal platform for nanoparticles encapsulation and precisely controlled combination chemotherapy. Copyright © 2014 Elsevier Ltd. All rights reserved.

  8. Simulation of rectifier voltage malfunction on OWECS, four-level converter, HVDC light link: Smart grid context tool

    International Nuclear Information System (INIS)

    Seixas, M.; Melício, R.; Mendes, V.M.F.

    2015-01-01

    Highlights: • Floating offshore wind turbine in deep water. • DC link and voltage malfunction. • Converter topology considered is four-level. • Controllers are based on fractional-order. • Smart grid context. - Abstract: This paper presents a model for the simulation of an offshore wind system having a rectifier input voltage malfunction at one phase. The offshore wind system model comprises a variable-speed wind turbine supported on a floating platform, equipped with a permanent magnet synchronous generator using full-power four-level neutral point clamped converter. The link from the offshore floating platform to the onshore electrical grid is done through a light high voltage direct current submarine cable. The drive train is modeled by a three-mass model. Considerations about the smart grid context are offered for the use of the model in such a context. The rectifier voltage malfunction domino effect is presented as a case study to show capabilities of the model

  9. High reliability megawatt transformer/rectifier

    Science.gov (United States)

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

    1991-01-01

    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.

  10. High aspect ratio silicon nanowires control fibroblast adhesion and cytoskeleton organization

    Science.gov (United States)

    Andolfi, Laura; Murello, Anna; Cassese, Damiano; Ban, Jelena; Dal Zilio, Simone; Lazzarino, Marco

    2017-04-01

    Cell-cell and cell-matrix interactions are essential to the survival and proliferation of most cells, and are responsible for triggering a wide range of biochemical pathways. More recently, the biomechanical role of those interactions was highlighted, showing, for instance, that adhesion forces are essential for cytoskeleton organization. Silicon nanowires (Si NWs) with their small size, high aspect ratio and anisotropic mechanical response represent a useful model to investigate the forces involved in the adhesion processes and their role in cellular development. In this work we explored and quantified, by single cell force spectroscopy (SCFS), the interaction of mouse embryonic fibroblasts with a flexible forest of Si NWs. We observed that the cell adhesion forces are comparable to those found on collagen and bare glass coverslip, analogously the membrane tether extraction forces are similar to that on collagen but stronger than that on bare flat glass. Cell survival did not depend significantly on the substrate, although a reduced proliferation after 36 h was observed. On the contrary both cell morphology and cytoskeleton organization revealed striking differences. The cell morphology on Si-NW was characterized by a large number of filopodia and a significant decrease of the cell mobility. The cytoskeleton organization was characterized by the absence of actin fibers, which were instead dominant on collagen and flat glass support. Such findings suggest that the mechanical properties of disordered Si NWs, and in particular their strong asymmetry, play a major role in the adhesion, morphology and cytoskeleton organization processes. Indeed, while adhesion measurements by SCFS provide out-of-plane forces values consistent with those measured on conventional substrates, weaker in-plane forces hinder proper cytoskeleton organization and migration processes.

  11. Processes controlling silicon isotopic fractionation in a forested tropical watershed: Mule Hole Critical Zone Observatory (Southern India)

    Science.gov (United States)

    Riotte, Jean; Meunier, Jean-Dominique; Zambardi, Thomas; Audry, Stéphane; Barboni, Doris; Anupama, Krishnamurthy; Prasad, Srinivasan; Chmeleff, Jérôme; Poitrasson, Franck; Sekhar, Muddu; Braun, Jean-Jacques

    2018-05-01

    that up to 4100 mol ha-1 yr-1 of silica is taken up by vegetation, which is almost twice as large as that initially estimated from the elemental budget. The additional Si flux taken up, and likely stored in woody stems, was estimated assuming that Si isotopes followed a steady-state model for the whole Si plant uptake and then followed a Rayleigh model once in the plants. The δ30Si value of the additional Si flux taken up should be close to 0‰, i.e., enriched in light Si isotopes compared to the litter. If steady-state conditions apply, the source could correspond to soil ASi dissolution or deep (saprolite) root uptake. At the outlet of the watershed, the stream exhibits low δ30Si values (0.28-0.71‰) during peak flows and high δ30Si values (1.29-1.61‰) during the recessions at the end of the rainy season. Heavy δ30Si signatures are consistent with the expected domination of seepage at the end of floods. The light δ30Si values during peak flow are slightly lower than the overland flow signature and reflect either a sampling bias of overland flow or a minor but significant contribution of another Si source within the stream, possibly the partial dissolution of phytoliths from the suspended load, with slight isotopic fractionation. This study confirms that vegetation controls the silicon cycle in this dry tropical forest. It also shows that silicon isotopes yield a better grasp of the mass balance and sources and potential mechanisms involved than the consideration of only silicon concentrations. However, this proxy still relies on working hypotheses, notably steady-state and/or Rayleigh fractionation models, which need to be confirmed in further studies.

  12. InGaAs-based planar barrier diode as microwave rectifier

    Science.gov (United States)

    Farhani Zakaria, Nor; Rizal Kasjoo, Shahrir; Zailan, Zarimawaty; Mohamad Isa, Muammar; Arshad, Mohd Khairuddin Md; Taking, Sanna

    2018-06-01

    In this report, we proposed and simulated a new planar nonlinear rectifying device fabricated using InGaAs substrate and referred to as a planar barrier diode (PBD). Using an asymmetrical inverse-arrowhead-shaped structure between the electrodes, a nonuniform depletion region is developed, which creates a triangular energy barrier in the conducting channel. This barrier is voltage dependent and can be controlled by the applied voltage across the PBD, thus resulting in nonlinear diode-like current–voltage characteristics; thus it can be used as a rectifying device. The PBD’s working principle is explained using thermionic emission theory. Furthermore, by varying the PBD’s geometric design, the asymmetry of the current–voltage characteristics can be optimized to realize superior rectification performance. By employing the optimized structural parameters, the obtained cut-off frequency of the device was approximately 270 GHz with a curvature coefficient peak of 14 V‑1 at a low DC bias voltage of 50 mV.

  13. Optimization of Controllable Factors in the Aluminum Silicon Eutectic Paste and Rear Silicon Nitride Mono-Passivation Layer of PERC Solar Cells

    Science.gov (United States)

    Park, Sungeun; Park, Hyomin; Kim, Dongseop; Yang, JungYup; Lee, Dongho; Kim, Young-Su; Kim, Hyun-Jong; Suh, Dongchul; Min, Byoung Koun; Kim, Kyung Nam; Park, Se Jin; Kim, Donghwan; Lee, Hae-Seok; Nam, Junggyu; Kang, Yoonmook

    2018-05-01

    Passivated emitter and rear contact (PERC) is a promising technology owing to high efficiency can be achieved with p-type wafer and their easily applicable to existing lines. In case of using p-type mono wafer, 0.5-1% efficiency increase is expected with PERC technologies compared to existing Al BSF solar cells, while for multi-wafer solar cells it is 0.5-0.8%. We addressed the optimization of PERC solar cells using the Al paste. The paste was prepared from the aluminum-silicon alloy with eutectic composition to avoid the formation of voids that degrade the open-circuit voltage. The glass frit of the paste was changed to improve adhesion. Scanning electron microscopy revealed voids and local back surface field between the aluminum electrode and silicon base. We confirmed the conditions on the SiNx passivation layer for achieving higher efficiency and better adhesion for long-term stability. The cell characteristics were compared across cells containing different pastes. PERC solar cells with the Al/Si eutectic paste exhibited the efficiency of 19.6%.

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

    Energy Technology Data Exchange (ETDEWEB)

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

    2013-01-01

    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.

  15. Zero sequence blocking transformers for multi-pulse rectifier in aerospace applications

    DEFF Research Database (Denmark)

    Yao, Wenli; Blaabjerg, Frede; Zhang, Xiaobin

    2014-01-01

    The power electronics technology plays an even more important role in the aerospace applications of More Electric Aircrafts (MEA). AutoTransformer Rectifier Units (ATRU) have been widely adopted in aircrafts due to its simplicity and reliability. In this paper, Zero Sequence Blocking Transformers...... (ZSBT) are employed in the DC link to realize parallel rectifier bridges for ATRU, being the proposed 24-pulse rectifier. A star-connected autotransformer is used in this topology to divide the primary side voltage into four three-phase voltage groups, among which there is a phase shift of 15......°. The autotransformer then feeds the load through rectifier bridges, which are in parallel with ZSBTs. Compared to the traditional method that is using six interphase transformers to parallel the rectifier bridges; the proposed 24-pulse rectifier only requires four ZSBTs. This will contribute to a reduction of weight...

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

    International Nuclear Information System (INIS)

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

    2015-01-01

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

  17. Effectiveness of the custom-mold room temperature vulcanizing silicone toe separator on hallux valgus: A prospective, randomized single-blinded controlled trial.

    Science.gov (United States)

    Chadchavalpanichaya, Navaporn; Prakotmongkol, Voraluck; Polhan, Nattapong; Rayothee, Pitchaya; Seng-Iad, Sirirat

    2018-04-01

    Silicone toe separator is considered as a conservative treatment for hallux valgus. The prefabricated toe separator does not fit all. However, effectiveness in prescription of the custom-mold toe separator is still unknown. To investigate the effect of using a custom-mold room temperature vulcanizing silicone toe separator to decrease hallux valgus angle and hallux pain. The compliances, complications, and satisfactions of toe separator were also explored. A prospective, randomized single-blinded controlled trial. A total of 90 patients with a moderate degree of hallux valgus were enrolled in a study at the Foot Clinic, Siriraj Hospital, Thailand. Patients were randomized into two groups; the study group was prescribed a custom-mold room temperature vulcanizing silicone toe separator for 6 h per night for 12 months. Patients in both groups received proper foot care and shoes and were permitted to continue drug treatment. In total, 40 patients in the study group and 39 patients in the control group completed the study. The hallux valgus angle was obtained through radiographic measurement. At month 12, both groups had significant differences in mean hallux valgus angle with a decrease of 3.3° ± 2.4° for the study group and increase of 1.9° ± 1.9° for the control group. There were statistically significant differences of hallux valgus angle between the two groups ( p Hallux pain was decreased in the study group. A custom-mold room temperature vulcanizing silicone toe separator can decrease hallux valgus angle and pain with no serious complications. Clinical relevance The custom-mold room temperature vulcanizing silicone toe separator for treatment of hallux valgus reduces deformity and hallux pain.

  18. Memory characteristics of silicon nitride with silicon nanocrystals as a charge trapping layer of nonvolatile memory devices

    International Nuclear Information System (INIS)

    Choi, Sangmoo; Yang, Hyundeok; Chang, Man; Baek, Sungkweon; Hwang, Hyunsang; Jeon, Sanghun; Kim, Juhyung; Kim, Chungwoo

    2005-01-01

    Silicon nitride with silicon nanocrystals formed by low-energy silicon plasma immersion ion implantation has been investigated as a charge trapping layer of a polycrystalline silicon-oxide-nitride-oxide-silicon-type nonvolatile memory device. Compared with the control sample without silicon nanocrystals, silicon nitride with silicon nanocrystals provides excellent memory characteristics, such as larger width of capacitance-voltage hysteresis, higher program/erase speed, and lower charge loss rate at elevated temperature. These improved memory characteristics are derived by incorporation of silicon nanocrystals into the charge trapping layer as additional accessible charge traps with a deeper effective trap energy level

  19. Development of controlled release silicone adhesive-based mupirocin patch demonstrates antibacterial activity on live rat skin against Staphylococcus aureus.

    Science.gov (United States)

    David, Sheba R; Malek, Nurafiqah; Mahadi, Abdul Hanif; Chakravarthi, Srikumar; Rajabalaya, Rajan

    2018-01-01

    Peritonitis is the most serious complication of peritoneal dialysis. Staphylococcus aureus infections could lead to peritonitis which causes reversal of peritoneal dialysis treatment back to hemodialysis. The aim of this study was to develop a controlled release silicone adhesive-based mupirocin patch for prophylactic effect and analyze its antibacterial effectiveness against S. aureus . The matrix patches were prepared by using different polymers, with and without silicone adhesive, dibutyl sebacate and mupirocin. The patches were characterized for mechanical properties, drug content, moisture content, water absorption capacity and Fourier transform infrared spectrum. In vitro release studies were performed by using Franz diffusion cell. In vitro disk diffusion assay was performed on the Mueller-Hinton Agar plate to measure the zone of inhibition of the patches. The in vivo study was performed on four groups of rats with bacterial counts at three different time intervals, along with skin irritancy and histopathologic studies. The patches showed appropriate average thickness (0.63-1.12 mm), tensile strength (5.08-10.08 MPa) and modulus of elasticity (21.53-42.19 MPa). The drug content ranged from 94.5% to 97.4%, while the moisture content and water absorption capacities at two relative humidities (75% and 93%) were in the range of 1.082-3.139 and 1.287-4.148 wt%, respectively. Fourier transform infrared spectra showed that there were no significant interactions between the polymer and the drug. The highest percentage of drug release at 8 hours was 47.94%. The highest zone of inhibition obtained was 28.3 mm against S. aureus . The in vivo studies showed that the bacterial colonies were fewer at 1 cm (7×10 1 CFU/mL) than at 2 cm (1.3×10 2 CFU/mL) over a 24-hour period. The patches were nonirritant to the skin, and histopathologic results also showed no toxic or damaging effects to the skin. The in vitro and in vivo studies indicated that controlled release patches

  20. Rectifying calibration error of Goldmann applanation tonometer is easy!

    Directory of Open Access Journals (Sweden)

    Nikhil S Choudhari

    2014-01-01

    Full Text Available Purpose: Goldmann applanation tonometer (GAT is the current Gold standard tonometer. However, its calibration error is common and can go unnoticed in clinics. Its company repair has limitations. The purpose of this report is to describe a self-taught technique of rectifying calibration error of GAT. Materials and Methods: Twenty-nine slit-lamp-mounted Haag-Streit Goldmann tonometers (Model AT 900 C/M; Haag-Streit, Switzerland were included in this cross-sectional interventional pilot study. The technique of rectification of calibration error of the tonometer involved cleaning and lubrication of the instrument followed by alignment of weights when lubrication alone didn′t suffice. We followed the South East Asia Glaucoma Interest Group′s definition of calibration error tolerance (acceptable GAT calibration error within ±2, ±3 and ±4 mm Hg at the 0, 20 and 60-mm Hg testing levels, respectively. Results: Twelve out of 29 (41.3% GATs were out of calibration. The range of positive and negative calibration error at the clinically most important 20-mm Hg testing level was 0.5 to 20 mm Hg and -0.5 to -18 mm Hg, respectively. Cleaning and lubrication alone sufficed to rectify calibration error of 11 (91.6% faulty instruments. Only one (8.3% faulty GAT required alignment of the counter-weight. Conclusions: Rectification of calibration error of GAT is possible in-house. Cleaning and lubrication of GAT can be carried out even by eye care professionals and may suffice to rectify calibration error in the majority of faulty instruments. Such an exercise may drastically reduce the downtime of the Gold standard tonometer.

  1. Solidification interface shape control in a continuous Czochralski silicon growth system

    Science.gov (United States)

    Wang, Chenlei; Zhang, Hui; Wang, Tihu; Zheng, Lili

    2006-01-01

    In a continuous Czochralski (CCZ) growth system with a shallow and replenished melt proposed earlier, large-diameter crystals may be grown at a high pull rate and reduced melt convection. The proposed system consists of two heaters. In this paper, the relationship between the solidification interface and the power levels is established. An interface control algorithm is developed to achieve the desired interface shape by adjusting the power level of the bottom heater. The control algorithm is incorporated into an existing process model, and the efficiency of the control algorithm is tested.

  2. Optical force rectifiers based on PT-symmetric metasurfaces

    Science.gov (United States)

    Alaee, Rasoul; Gurlek, Burak; Christensen, Johan; Kadic, Muamer

    2018-05-01

    We introduce here the concept of optical force rectifier based on parity-time symmetric metasurfaces. Directly linked to the properties of non-Hermitian systems engineered by balanced loss and gain constituents, we show that light can exert asymmetric pulling or pushing forces on metasurfaces depending on the direction of the impinging light. This generates a complete force rectification in the vicinity of the exceptional point. Our findings have the potential to spark the design of applications in optical manipulation where the forces, strictly speaking, act unidirectionally.

  3. Torsion angle dependence of the rectifying performance in molecular device with asymmetrical anchoring groups

    International Nuclear Information System (INIS)

    Wang, L.H.; Guo, Y.; Tian, C.F.; Song, X.P.; Ding, B.J.

    2010-01-01

    Using first-principles density functional theory and nonequilibrium Green's function formalism, we investigate the effect of torsion angle on the rectifying characteristics of 4'-thiolate-biphenyl-4-dithiocarboxylate sandwiched between two Au(111) electrodes. The results show that the torsion angle has an evident influence on rectifying performance of such devices. By increasing the dihedral angle between two phenyl rings, namely changing the magnitude of the intermolecular coupling effect, a different rectifying behavior can be observed in these systems. Our findings highlight that the rectifying characteristics are intimately related to dihedral angles and can provide fundamental guidelines for the design of functional molecular devices.

  4. Study of 18-Pulse Rectifier Utilizing Hexagon Connected 3-Phase to 9-Phase Transformer

    Directory of Open Access Journals (Sweden)

    Ahmad Saudi Samosir

    2008-04-01

    Full Text Available The 18-pulse converter, using Y or -connected differential autotransformer, is very interesting since it allows natural high power factor correction. The lowest input current harmonic components are the 17th and 19th. The Transformer is designed to feed three six-pulse bridge rectifiers displaced in phase by 200. This paper present a high power factor three-phase rectifier bases on 3-phase to 9-phase transformer and 18-pulse rectifier. The 9-phase polygon-connected transformer followed by 18-pulse diode rectifiers ensures the fundamental concept of natural power factor correction. Simulation results to verify the proposed concept are shown in this paper.

  5. Current status of self rectifying air turbines for wave energy conversion

    International Nuclear Information System (INIS)

    Setoguchi, Toshiaki; Takao, Manabu

    2006-01-01

    This paper reviews the present state of the art on self rectifying air turbines, which could be used for wave energy conversion. The overall performances of the turbines under irregular wave conditions, which typically occur in the sea, have been evaluated numerically and compared from the viewpoints of their starting and running characteristics. The types of turbine included in the paper are: (a) Wells turbine with guide vanes (WTGV); (b) turbine with self-pitch-controlled blades (TSCB); (c) biplane Wells turbine with guide vanes (BWGV); (d) impulse turbine with self-pitch-controlled guide vanes (ISGV); and (e) impulse turbine with fixed guide vanes (IFGV). As a result, under irregular wave conditions, it is found that the running and starting characteristics of impulse type turbines could be superior to those of the Wells turbine. Moreover, the authors have explained the mechanism of the hysteretic behavior of the Wells turbine and the necessity of links for improvement of the performance of the ISGV

  6. Differential roles of two delayed rectifier potassium currents in regulation of ventricular action potential duration and arrhythmia susceptibility.

    Science.gov (United States)

    Devenyi, Ryan A; Ortega, Francis A; Groenendaal, Willemijn; Krogh-Madsen, Trine; Christini, David J; Sobie, Eric A

    2017-04-01

    Arrhythmias result from disruptions to cardiac electrical activity, although the factors that control cellular action potentials are incompletely understood. We combined mathematical modelling with experiments in heart cells from guinea pigs to determine how cellular electrical activity is regulated. A mismatch between modelling predictions and the experimental results allowed us to construct an improved, more predictive mathematical model. The balance between two particular potassium currents dictates how heart cells respond to perturbations and their susceptibility to arrhythmias. Imbalances of ionic currents can destabilize the cardiac action potential and potentially trigger lethal cardiac arrhythmias. In the present study, we combined mathematical modelling with information-rich dynamic clamp experiments to determine the regulation of action potential morphology in guinea pig ventricular myocytes. Parameter sensitivity analysis was used to predict how changes in ionic currents alter action potential duration, and these were tested experimentally using dynamic clamp, a technique that allows for multiple perturbations to be tested in each cell. Surprisingly, we found that a leading mathematical model, developed with traditional approaches, systematically underestimated experimental responses to dynamic clamp perturbations. We then re-parameterized the model using a genetic algorithm, which allowed us to estimate ionic current levels in each of the cells studied. This unbiased model adjustment consistently predicted an increase in the rapid delayed rectifier K + current and a drastic decrease in the slow delayed rectifier K + current, and this prediction was validated experimentally. Subsequent simulations with the adjusted model generated the clinically relevant prediction that the slow delayed rectifier is better able to stabilize the action potential and suppress pro-arrhythmic events than the rapid delayed rectifier. In summary, iterative coupling of

  7. Gold nanoparticle growth control - Implementing novel wet chemistry method on silicon substrate

    KAUST Repository

    Al-Ameer, Ammar; Katsiev, Habib; Sinatra, Lutfan; Hussein, Irshad; Bakr, Osman

    2013-01-01

    Controlling particle size, shape, nucleation, and self-assembly on surfaces are some of the main challenges facing electronic device fabrication. In this work, growth of gold nanoparticles over a wide range of sizes was investigated by using a novel

  8. Generic functional modelling of multi-pulse auto-transformer rectifier units for more-electric aircraft applications

    Directory of Open Access Journals (Sweden)

    Tao YANG

    2018-05-01

    Full Text Available The Auto-Transformer Rectifier Unit (ATRU is one preferred solution for high-power AC/DC power conversion in aircraft. This is mainly due to its simple structure, high reliability and reduced kVA ratings. Indeed, the ATRU has become a preferred AC/DC solution to supply power to the electric environment control system on-board future aircraft. In this paper, a general modelling method for ATRUs is introduced. The developed model is based on the fact that the DC voltage and current are strongly related to the voltage and current vectors at the AC terminals of ATRUs. In this paper, we carry on our research in modelling symmetric 18-pulse ATRUs and develop a generic modelling technique. The developed generic model can study not only symmetric but also asymmetric ATRUs. An 18-pulse asymmetric ATRU is used to demonstrate the accuracy and efficiency of the developed model by comparing with corresponding detailed switching SABER models provided by our industrial partner. The functional models also allow accelerated and accurate simulations and thus enable whole-scale more-electric aircraft electrical power system studies in the future. Keywords: Asymmetric transformer, Functional modelling, More-Electric Aircraft, Multi-pulse rectifier, Transformer rectifier unit

  9. Porous silicon: silicon quantum dots for photonic applications

    International Nuclear Information System (INIS)

    Pavesi, L.; Guardini, R.

    1996-01-01

    Porous silicon formation and structure characterization are briefly illustrated. Its luminescence properties rae presented and interpreted on the basis of exciton recombination in quantum dot structures: the trap-controlled hopping mechanism is used to describe the recombination dynamics. Porous silicon application to photonic devices is considered: porous silicon multilayer in general, and micro cavities in particular are described. The present situation in the realization of porous silicon LEDs is considered, and future developments in this field of research are suggested. (author). 30 refs., 30 figs., 13 tabs

  10. Fluorescence and thermoluminescence in silicon oxide films rich in silicon

    International Nuclear Information System (INIS)

    Berman M, D.; Piters, T. M.; Aceves M, M.; Berriel V, L. R.; Luna L, J. A.

    2009-10-01

    In this work we determined the fluorescence and thermoluminescence (TL) creation spectra of silicon rich oxide films (SRO) with three different silicon excesses. To study the TL of SRO, 550 nm of SRO film were deposited by Low Pressure Chemical Vapor Deposition technique on N-type silicon substrates with resistivity in the order of 3 to 5 Ω-cm with silicon excess controlled by the ratio of the gases used in the process, SRO films with Ro= 10, 20 and 30 (12-6% silicon excess) were obtained. Then, they were thermally treated in N 2 at high temperatures to diffuse and homogenize the silicon excess. In the fluorescence spectra two main emission regions are observed, one around 400 nm and one around 800 nm. TL creation spectra were determined by plotting the integrated TL intensity as function of the excitation wavelength. (Author)

  11. Micro-orientation control of silicon polymer thin films on graphite surfaces modified by heteroatom doping

    Energy Technology Data Exchange (ETDEWEB)

    Shimoyama, Iwao, E-mail: shimoyama.iwao@jaea.go.jp [Material Science Research Center, Atomic Energy Agency, Tokai-mura 2-4, Naka-gun, Ibaraki 319-1195 (Japan); Baba, Yuji [Fukushima Administrative Department, Atomic Energy Agency, Tokai-mura 2-4, Naka-gun, Ibaraki 319-1195 (Japan); Hirao, Norie [Material Science Research Center, Atomic Energy Agency, Tokai-mura 2-4, Naka-gun, Ibaraki 319-1195 (Japan)

    2017-05-31

    Highlights: • Micro-orientation control method for organic polysilane thin films is proposed. • This method utilizes surface modification of graphite using heteroatom doping. • Lying, standing, and random orientations can be freely controlled by this method. • Micro-pattering of a polysilane film with controlled orientations is achieved. - Abstract: Near-edge X-ray absorption fine structure (NEXAFS) spectroscopy is applied to study orientation structures of polydimethylsilane (PDMS) films deposited on heteroatom-doped graphite substrates prepared by ion beam doping. The Si K-edge NEXAFS spectra of PDMS show opposite trends of polarization dependence for non irradiated and N{sub 2}{sup +}-irradiated substrates, and show no polarization dependence for an Ar{sup +}-irradiated substrate. Based on a theoretical interpretation of the NEXAFS spectra via first-principles calculations, we clarify that PDMS films have lying, standing, and random orientations on the non irradiated, N{sub 2}{sup +}-irradiated, and Ar{sup +}-irradiated substrates, respectively. Furthermore, photoemission electron microscopy indicates that the orientation of a PDMS film can be controlled with microstructures on the order of μm by separating irradiated and non irradiated areas on the graphite surface. These results suggest that surface modification of graphite using ion beam doping is useful for micro-orientation control of organic thin films.

  12. On the Control of the Fixed Charge Densities in Al2O3-Based Silicon Surface Passivation Schemes.

    Science.gov (United States)

    Simon, Daniel K; Jordan, Paul M; Mikolajick, Thomas; Dirnstorfer, Ingo

    2015-12-30

    A controlled field-effect passivation by a well-defined density of fixed charges is crucial for modern solar cell surface passivation schemes. Al2O3 nanolayers grown by atomic layer deposition contain negative fixed charges. Electrical measurements on slant-etched layers reveal that these charges are located within a 1 nm distance to the interface with the Si substrate. When inserting additional interface layers, the fixed charge density can be continuously adjusted from 3.5 × 10(12) cm(-2) (negative polarity) to 0.0 and up to 4.0 × 10(12) cm(-2) (positive polarity). A HfO2 interface layer of one or more monolayers reduces the negative fixed charges in Al2O3 to zero. The role of HfO2 is described as an inert spacer controlling the distance between Al2O3 and the Si substrate. It is suggested that this spacer alters the nonstoichiometric initial Al2O3 growth regime, which is responsible for the charge formation. On the basis of this charge-free HfO2/Al2O3 stack, negative or positive fixed charges can be formed by introducing additional thin Al2O3 or SiO2 layers between the Si substrate and this HfO2/Al2O3 capping layer. All stacks provide very good passivation of the silicon surface. The measured effective carrier lifetimes are between 1 and 30 ms. This charge control in Al2O3 nanolayers allows the construction of zero-fixed-charge passivation layers as well as layers with tailored fixed charge densities for future solar cell concepts and other field-effect based devices.

  13. Control of heat transfer in continuous-feeding Czochralski-silicon crystal growth with a water-cooled jacket

    Science.gov (United States)

    Zhao, Wenhan; Liu, Lijun

    2017-01-01

    The continuous-feeding Czochralski method is an effective method to reduce the cost of single crystal silicon. By promoting the crystal growth rate, the cost can be reduced further. However, more latent heat will be released at the melt-crystal interface under a high crystal growth rate. In this study, a water-cooled jacket was applied to enhance the heat transfer at the melt-crystal interface. Quasi-steady-state numerical calculation was employed to investigate the impact of the water-cooled jacket on the heat transfer at the melt-crystal interface. Latent heat released during the crystal growth process at the melt-crystal interface and absorbed during feedstock melting at the feeding zone was modeled in the simulations. The results show that, by using the water-cooled jacket, heat transfer in the growing crystal is enhanced significantly. Melt-crystal interface deflection and thermal stress increase simultaneously due to the increase of radial temperature at the melt-crystal interface. With a modified heat shield design, heat transfer at the melt-crystal interface is well controlled. The crystal growth rate can be increased by 20%.

  14. DNA Physical Mapping via the Controlled Translocation of Single Molecules through a 5-10nm Silicon Nitride Nanopore

    Science.gov (United States)

    Stein, Derek; Reisner, Walter; Jiang, Zhijun; Hagerty, Nick; Wood, Charles; Chan, Jason

    2009-03-01

    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.

  15. Low temperature synthesis of silicon quantum dots with plasma chemistry control in dual frequency non-thermal plasmas.

    Science.gov (United States)

    Sahu, Bibhuti Bhusan; Yin, Yongyi; Han, Jeon Geon; Shiratani, Masaharu

    2016-06-21

    The advanced materials process by non-thermal plasmas with a high plasma density allows the synthesis of small-to-big sized Si quantum dots by combining low-temperature deposition with superior crystalline quality in the background of an amorphous hydrogenated silicon nitride matrix. Here, we make quantum dot thin films in a reactive mixture of ammonia/silane/hydrogen utilizing dual-frequency capacitively coupled plasmas with high atomic hydrogen and nitrogen radical densities. Systematic data analysis using different film and plasma characterization tools reveals that the quantum dots with different sizes exhibit size dependent film properties, which are sensitively dependent on plasma characteristics. These films exhibit intense photoluminescence in the visible range with violet to orange colors and with narrow to broad widths (∼0.3-0.9 eV). The observed luminescence behavior can come from the quantum confinement effect, quasi-direct band-to-band recombination, and variation of atomic hydrogen and nitrogen radicals in the film growth network. The high luminescence yields in the visible range of the spectrum and size-tunable low-temperature synthesis with plasma and radical control make these quantum dot films good candidates for light emitting applications.

  16. Silicon based cryogenic platform for the integration of qubit and classical control chips

    Science.gov (United States)

    Leonhardt, T.; Hollmann, A.; Jirovec, D.; Neumann, R.; Klemt, B.; Kindel, S.; Kucharski, M.; Fischer, G.; Bougeard, D.; Bluhm, H.; Schreiber, L. R.

    Electrostatically confined electron-spin-qubits proved viable for quantum information processing. Yet their up-scaling not only demands improvement of physical qubits, but also the development and cryogenic integration of classical control hardware. Therefore, we created a platform to integrate quantum chips and classical electronics. These multilayer interposer chips incorporate passive circuit elements, high bandwidth coplanar wave guides and interconnects for electron spin resonant qubit control as well as low impedance DC microstrips reducing EM-crosstalk from AC to DC lines. We used the interposer for measurements of a Si/SiGe quantum dot at 30 mK. We also characterized a commercial voltage controlled oszillator (VCO) based on hetero-bipolar transistors. Tunable about 30 GHz it is ideal for electron spin resonant qubit control. Cooled from 300 to 4 K it exhibits a slightly increased output power and frequency, while the phase noise level is constant. The device remains functional up to magnetic fields of 6 T.

  17. Complete Quantum Control of a Single Silicon-Vacancy Center in a Diamond Nanopillar

    Science.gov (United States)

    Zhang, Jingyuan Linda; Lagoudakis, Konstantinos G.; Tzeng, Yan-Kai; Dory, Constantin; Radulaski, Marina; Kelaita, Yousif; Shen, Zhi-Xun; Melosh, Nicholas A.; Chu, Steven; Vuckovic, Jelena

    Coherent quantum control of a quantum bit (qubit) is an important step towards its use in a quantum network. SiV- center in diamond offers excellent physical qualities such as low inhomogeneous broadening, fast photon emission, and a large Debye-Waller factor, while the fast spin manipulation and techniques to extend the spin coherence time are under active investigation. Here, we demonstrate full coherent control over the state of a single SiV- center in a diamond nanopillar using ultrafast optical pulses. The high quality of the chemical vapor deposition grown SiV- centers allows us to coherently manipulate and quasi-resonantly read out the state of the single SiV- center. Moreover, the SiV- centers being coherently controlled are integrated into diamond nanopillar arrays in a site-controlled, individually addressable manner with high yield, low strain, and high spectral stability, which paves the way for scalable on chip optically accessible quantum system in a quantum photonic network. Financial support is provided by the DOE Office of Basic Energy Sciences, Division of Materials Sciences through Stanford Institute for Materials and Energy Sciences (SIMES) under contract DE-AC02-76SF00515.

  18. Direct Production of Silicones From Sand

    Energy Technology Data Exchange (ETDEWEB)

    Larry N. Lewis; F.J. Schattenmann: J.P. Lemmon

    2001-09-30

    Silicon, in the form of silica and silicates, is the second most abundant element in the earth's crust. However the synthesis of silicones (scheme 1) and almost all organosilicon chemistry is only accessible through elemental silicon. Silicon dioxide (sand or quartz) is converted to chemical-grade elemental silicon in an energy intensive reduction process, a result of the exceptional thermodynamic stability of silica. Then, the silicon is reacted with methyl chloride to give a mixture of methylchlorosilanes catalyzed by cooper containing a variety of tract metals such as tin, zinc etc. The so-called direct process was first discovered at GE in 1940. The methylchlorosilanes are distilled to purify and separate the major reaction components, the most important of which is dimethyldichlorosilane. Polymerization of dimethyldichlorosilane by controlled hydrolysis results in the formation of silicone polymers. Worldwide, the silicones industry produces about 1.3 billion pounds of the basic silicon polymer, polydimethylsiloxane.

  19. Subwavelength silicon photonics

    International Nuclear Information System (INIS)

    Cheben, P.; Bock, P.J.; Schmid, J.H.; Lapointe, J.; Janz, S.; Xu, D.-X.; Densmore, A.; Delage, A.; Lamontagne, B.; Florjanczyk, M.; Ma, R.

    2011-01-01

    With the goal of developing photonic components that are compatible with silicon microelectronic integrated circuits, silicon photonics has been the subject of intense research activity. Silicon is an excellent material for confining and manipulating light at the submicrometer scale. Silicon optoelectronic integrated devices have the potential to be miniaturized and mass-produced at affordable cost for many applications, including telecommunications, optical interconnects, medical screening, and biological and chemical sensing. We review recent advances in silicon photonics research at the National Research Council Canada. A new type of optical waveguide is presented, exploiting subwavelength grating (SWG) effect. We demonstrate subwavelength grating waveguides made of silicon, including practical components operating at telecom wavelengths: input couplers, waveguide crossings and spectrometer chips. SWG technique avoids loss and wavelength resonances due to diffraction effects and allows for single-mode operation with direct control of the mode confinement by changing the refractive index of a waveguide core over a range as broad as 1.6 - 3.5 simply by lithographic patterning. The light can be launched to these waveguides with a coupling loss as small as 0.5 dB and with minimal wavelength dependence, using coupling structures similar to that shown in Fig. 1. The subwavelength grating waveguides can cross each other with minimal loss and negligible crosstalk which allows massive photonic circuit connectivity to overcome the limits of electrical interconnects. These results suggest that the SWG waveguides could become key elements for future integrated photonic circuits. (authors)

  20. Inward rectifier potassium currents in mammalian skeletal muscle fibres

    Science.gov (United States)

    DiFranco, Marino; Yu, Carl; Quiñonez, Marbella; Vergara, Julio L

    2015-01-01

    Inward rectifying potassium (Kir) channels play a central role in maintaining the resting membrane potential of skeletal muscle fibres. Nevertheless their role has been poorly studied in mammalian muscles. Immunohistochemical and transgenic expression were used to assess the molecular identity and subcellular localization of Kir channel isoforms. We found that Kir2.1 and Kir2.2 channels were targeted to both the surface andthe transverse tubular system membrane (TTS) compartments and that both isoforms can be overexpressed up to 3-fold 2 weeks after transfection. Inward rectifying currents (IKir) had the canonical features of quasi-instantaneous activation, strong inward rectification, depended on the external [K+], and could be blocked by Ba2+ or Rb+. In addition, IKir records show notable decays during large 100 ms hyperpolarizing pulses. Most of these properties were recapitulated by model simulations of the electrical properties of the muscle fibre as long as Kir channels were assumed to be present in the TTS. The model also simultaneously predicted the characteristics of membrane potential changes of the TTS, as reported optically by a fluorescent potentiometric dye. The activation of IKir by large hyperpolarizations resulted in significant attenuation of the optical signals with respect to the expectation for equal magnitude depolarizations; blocking IKir with Ba2+ (or Rb+) eliminated this attenuation. The experimental data, including the kinetic properties of IKir and TTS voltage records, and the voltage dependence of peak IKir, while measured at widely dissimilar bulk [K+] (96 and 24 mm), were closely predicted by assuming Kir permeability (PKir) values of ∼5.5 × 10−6 cm s−1 and equal distribution of Kir channels at the surface and TTS membranes. The decay of IKir records and the simultaneous increase in TTS voltage changes were mostly explained by K+ depletion from the TTS lumen. Most importantly, aside from allowing an accurate estimation of

  1. Formation mechanism and control of MgO·Al2O3 inclusions in non-oriented silicon steel

    Science.gov (United States)

    Sun, Yan-hui; Zeng, Ya-nan; Xu, Rui; Cai, Kai-ke

    2014-11-01

    On the basis of the practical production of non-oriented silicon steel, the formation of MgO·Al2O3 inclusions was analyzed in the process of "basic oxygen furnace (BOF) → RH → compact strip production (CSP)". The thermodynamic and kinetic conditions of the formation of MgO·Al2O3 inclusions were discussed, and the behavior of slag entrapment in molten steel during RH refining was simulated by computational fluid dynamics (CFD) software. The results showed that the MgO/Al2O3 mass ratio was in the range from 0.005 to 0.017 and that MgO·Al2O3 inclusions were not observed before the RH refining process. In contrast, the MgO/Al2O3 mass ratio was in the range from 0.30 to 0.50, and the percentage of MgO·Al2O3 spinel inclusions reached 58.4% of the total inclusions after the RH refining process. The compositions of the slag were similar to those of the inclusions; furthermore, the critical velocity of slag entrapment was calculated to be 0.45 m·s-1 at an argon flow rate of 698 L·min-1, as simulated using CFD software. When the test steel was in equilibrium with the slag, [Mg] was 0.00024wt%-0.00028wt% and [Al]s was 0.31wt%-0.37wt%; these concentrations were theoretically calculated to fall within the MgO·Al2O3 formation zone, thereby leading to the formation of MgO·Al2O3 inclusions in the steel. Thus, the formation of MgO·Al2O3 inclusions would be inhibited by reducing the quantity of slag entrapment, controlling the roughing slag during casting, and controlling the composition of the slag and the MgO content in the ladle refractory.

  2. Commissioning of the control and data acquisition electronics for the CDF Silicon Vertex Detector

    International Nuclear Information System (INIS)

    Tkaczyk, S.M.; Turner, K.J.; Nelson, C.A.; Shaw, T.M.; Wesson, T.R.; Bailey, M.W.; Kruse, M.C.; Castro, A.

    1991-11-01

    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

  3. A pulsed load model and its impact on a synchronous-rectifier system

    Science.gov (United States)

    Hou, Pengfei; Xu, Ye; Li, Jianke; Wang, Jinquan; Zhang, Haitao; Yan, Jun; Wang, Chunming; Chen, Jingjing

    2017-02-01

    The pulsed load has become a developing trend of power loading. Unlike traditional loads, pulsed loads with current abrupt and repeated charges will result in unstable Microgrid operations because of their small capacity and inertia. In this paper, an Average Magnitude Sum Function (AMSF) is proposed to calculate the frequency of the grid, and based on AMSF, the Relative Deviation Rate (RDR) that characterises the impact of pulsed load on the AC side of the grid is defined and its calculation process is described in detail. In addition, the system dynamic characteristics under a pulsed load are analysed using an Insulated Gate Bipolar Transistor (IGBT) to control the on/off state of the resistive load for simulating a pulsed load. Finally, the transient characteristics of a synchronous-rectifier system with a pulsed load are studied and validated experimentally.

  4. Decreased inward rectifier potassium current IK1 in dystrophin-deficient ventricular cardiomyocytes.

    Science.gov (United States)

    Rubi, Lena; Koenig, Xaver; Kubista, Helmut; Todt, Hannes; Hilber, Karlheinz

    2017-03-04

    Kir2.x channels in ventricular cardiomyocytes (most prominently Kir2.1) account for the inward rectifier potassium current I K1 , which controls the resting membrane potential and the final phase of action potential repolarization. Recently it was hypothesized that the dystrophin-associated protein complex (DAPC) is important in the regulation of Kir2.x channels. To test this hypothesis, we investigated potential I K1 abnormalities in dystrophin-deficient ventricular cardiomyocytes derived from the hearts of Duchenne muscular dystrophy mouse models. We found that I K1 was substantially diminished in dystrophin-deficient cardiomyocytes when compared to wild type myocytes. This finding represents the first functional evidence for a significant role of the DAPC in the regulation of Kir2.x channels.

  5. A vector modulated three-phase four-quadrant rectifier - Application to a dc motor drive

    Energy Technology Data Exchange (ETDEWEB)

    Jussila, Matti; Salo, Mika; Kaehkoenen, Lauri; Tuusa, Heikki

    2004-07-01

    This paper introduces a theory for a space vector modulation of a three-phase four-quadrant PWM rectifier (FQR). The presented vector modulation method is simple to realize with a microcontroller and it replaces the conventional modulation methods based on the analog technology. The FQR may be used to supply directly a dc load, e.g. a dc machine. The vector modulated FQR is tested in simulations supplying a 4.5 kW dc motor. The simulations show the benefits of the vector modulated FQR against thyristor converters: the supply currents are sinusoidal and the displacement power factor of the supply can be controlled. Furthermore the load current is smooth. (author)

  6. Orientation- and position-controlled alignment of asymmetric silicon microrod on a substrate with asymmetric electrodes

    Science.gov (United States)

    Shibata, Akihide; Watanabe, Keiji; Sato, Takuya; Kotaki, Hiroshi; Schuele, Paul J.; Crowder, Mark A.; Zhan, Changqing; Hartzell, John W.; Nakatani, Ryoichi

    2014-03-01

    In this paper, we demonstrate the orientation-controlled alignment of asymmetric Si microrods on a glass substrate with an asymmetric pair of electrodes. The Si microrods have the shape of a paddle with a blade and a shaft part, and the pair of electrodes consists of a narrow electrode and a wide electrode. By applying AC bias to the electrodes, the Si microrods suspended in a fluid align in such a way to settle across the electrode pair, and over 80% of the aligned Si microrods have an orientation with the blade and the shaft of the paddle on the wide and the narrow electrodes, respectively. When Si microrods have a shell of dielectric film and its thickness on the top face is thicker than that on the bottom face, 97.8% of the Si microrods are aligned with the top face facing upwards. This technique is useful for orientation-controlled alignment of nano- and microsized devices that have polarity or a distinction between the top and bottom faces.

  7. Online readout and control unit for high-speed/high resolution readout of silicon tracking detectors

    International Nuclear Information System (INIS)

    Buerger, J.; Hansen, K.; Lange, W.; Nowak, T.; Prell, S.; Zimmermann, W.

    1997-01-01

    We are describing a high speed VME readout and control module developed and presently working at the H1 experiment at DESY in Hamburg. It has the capability to read out 4 x 2048 analogue data channels at sampling rates up to 10 MHz with a dynamic input range of 1 V. The nominal resolution of the A/D converters can be adjusted between 8 and 12 bit. At the latter resolution we obtain signal-to-noise ratio better than 61.4 dB at a conversion rate of 5 MSps. At this data rate all 8192 detector channels can be read out to the internal raw data memory and VME interface within about 410 μs and 510 μs, respectively. The pedestal subtracted signals can be analyzed on-line. At a raw data hit occupation of 10%, the VME readout time is 50 μs per module. Each module provides four complementary CMOS signals to control the front-end electronics and four independent sets of power supplies for analogue and digital voltages (10 V, 100 mA) to drive the front-end electronics and for the bias voltage (100 V, 1.2 mA) to assure the full functionality of the detectors and the readout. (orig.)

  8. Online readout and control unit for high-speed/high resolution readout of silicon tracking detectors

    Science.gov (United States)

    Bürger, J.; Hansen, K.; Lange, W.; Nowak, T.; Prell, S.; Zimmermann, W.

    1997-02-01

    We are describing a high speed VME readout and control module developed and presently working at the H1 experiment at DESY in Hamburg. It has the capability to read out 4 × 2048 analogue data channels at sampling rates up to 10 MHz with a dynamic input range of 1 V. The nominal resolution of the A/D converters can be adjusted between 8 and 12 bit. At the latter resolution we obtain signal-to-noise ratio better than 61.4 dB at a conversion rate of 5 MSps. At this data rate all 8192 detector channels can be read out to the internal raw data memory and VME interface within about 410 μs and 510 μs, respectively. The pedestal subtracted signals can be analyzed on-line. At a raw data hit occupation of 10%, the VME readout time is 50 μs per module. Each module provides four complementary CMOS signals to control the front-end electronics and four independent sets of power supplies for analogue and digital voltages (10 V, 100 mA) to drive the front-end electronics and for the bias voltage (100 V, 1.2 mA) to assure the full functionality of the detectors and the readout.

  9. Online readout and control unit for high-speed / high resolution readout of silicon tracking detectors

    International Nuclear Information System (INIS)

    Buerger, J.; Hansen, K.; Lange, W.; Nowak, T.; Prell, S.; Zimmermann, W.

    1996-09-01

    We are describing a high speed VME readout and control module developed and presently working at the H1 experiment at DESY in Hamburg. It has the capability to read out 4 x 2048 analogue data channels at sampling rates up to 10 MHz with a dynamic input range of 1 V. The nominal resolution of the A/D converters can be adjusted between 8 and 12 bit. At the latter resolution we obtain signal-to-noise ratio better than 61.4 dB at a conversion rate of 5 MSps. At this data rate all 8192 detector channels can be read out to the internal raw data memory and VME interface within about 410 μs and 510 μs, respectively. The pedestal subtracted signals can be analyzed on-line. At a raw data hit occupation of 10%, the VME readout time is 50 μs per module. Each module provides four complementary CMOS signals to control the front-end electronics and four independent sets of power supplies for analogue and digital voltages (10 V, 100 mA) to drive the front-end electronics and for the bias voltage (100 V, 1.2 mA) to assure the full functionality of the detectors and the readout. (orig.)

  10. A high-power magnetically switched superconducting rectifier operating at 5 Hz

    NARCIS (Netherlands)

    Mulder, G.B.J.; Krooshoop, Hendrikus J.G.; Nijhuis, Arend; ten Kate, Herman H.J.; van de Klundert, L.J.M.

    1987-01-01

    Above a certain current level, the use of a superconducting rectifier as a cryogenic current source offers advantages compared to the use of a power supply at room temperature which requires large current feed-throughs into the cryostat. In some cases, the power of such a rectifier is immaterial,

  11. G-protein-coupled inward rectifier potassium current contributes to ventricular repolarization

    DEFF Research Database (Denmark)

    Liang, Bo; Nissen, Jakob D; Laursen, Morten

    2014-01-01

    The purpose of this study was to investigate the functional role of G-protein-coupled inward rectifier potassium (GIRK) channels in the cardiac ventricle.......The purpose of this study was to investigate the functional role of G-protein-coupled inward rectifier potassium (GIRK) channels in the cardiac ventricle....

  12. A Novel Current-Mode Full-Wave Rectifier Based on One CDTA and Two Diodes

    Directory of Open Access Journals (Sweden)

    F. Khateb

    2010-09-01

    Full Text Available Precision rectifiers are important building blocks for analog signal processing. The traditional approach based on diodes and operational amplifiers (OpAmps exhibits undesirable effects caused by limited OpAmp slew rate and diode commutations. In the paper, a full-wave rectifier based on one CDTA and two Schottky diodes is presented. The PSpice simulation results are included.

  13. Ultrafast terahertz control of extreme tunnel currents through single atoms on a silicon surface

    DEFF Research Database (Denmark)

    Jelic, Vedran; Iwaszczuk, Krzysztof; Nguyen, Peter H.

    2017-01-01

    scanning tunnelling microscopy (THz-STM) in ultrahigh vacuum as a new platform for exploring ultrafast non-equilibrium tunnelling dynamics with atomic precision. Extreme terahertz-pulse-driven tunnel currents up to 10(7) times larger than steady-state currents in conventional STM are used to image...... terahertz-induced band bending and non-equilibrium charging of surface states opens new conduction pathways to the bulk, enabling extreme transient tunnel currents to flow between the tip and sample.......Ultrafast control of current on the atomic scale is essential for future innovations in nanoelectronics. Extremely localized transient electric fields on the nanoscale can be achieved by coupling picosecond duration terahertz pulses to metallic nanostructures. Here, we demonstrate terahertz...

  14. Silicon containing copolymers

    CERN Document Server

    Amiri, Sahar; Amiri, Sanam

    2014-01-01

    Silicones have unique properties including thermal oxidative stability, low temperature flow, high compressibility, low surface tension, hydrophobicity and electric properties. These special properties have encouraged the exploration of alternative synthetic routes of well defined controlled microstructures of silicone copolymers, the subject of this Springer Brief. The authors explore the synthesis and characterization of notable block copolymers. Recent advances in controlled radical polymerization techniques leading to the facile synthesis of well-defined silicon based thermo reversible block copolymers?are described along with atom transfer radical polymerization (ATRP), a technique utilized to develop well-defined functional thermo reversible block copolymers. The brief also focuses on Polyrotaxanes and their great potential as stimulus-responsive materials which produce poly (dimethyl siloxane) (PDMS) based thermo reversible block copolymers.

  15. Self-Biased Differential Rectifier with Enhanced Dynamic Range for Wireless Powering

    KAUST Repository

    Ouda, Mahmoud H.

    2016-08-29

    A self-biased, cross-coupled, differential rectifier is proposed with enhanced power-conversion efficiency over an extended range of input power. A prototype is designed for UHF 433MHz RF power-harvesting applications and is implemented using 0.18μm CMOS technology. The proposed rectifier architecture is compared to the conventional cross-coupled rectifier. It demonstrates an improvement of more than 40% in the rectifier power conversion efficiency (PCE) and an input power range extension of more than 50% relative to the conventional crosscoupled rectifier. A sensitivity of -15.2dBm (30μW) input power for 1V output voltage and a peak power-conversion efficiency of 65% are achieved for a 50kω load. © 2004-2012 IEEE.

  16. A passive UHF RFID tag with a dynamic-Vth-cancellation rectifier

    International Nuclear Information System (INIS)

    Shen Jinpeng; Wang Bo; Liu Shan; Wang Xin'an; Ruan Zhengkun; Li Shoucheng

    2013-01-01

    This paper presents a passive UHF RFID tag with a dynamic-V th -cancellation (DVC) rectifier. In the rectifier, the threshold voltages of MOSFETs are cancelled by applying gate bias voltages, which are dynamically changed according to the states of the MOSFETs. The DVC rectifier enables both low ON-resistance and small reverse leakage of the MOSFETs, resulting in high power conversion efficiency (PCE). An area-efficient demodulator with a novel average detector is also designed, which takes advantage of the rectifier's first stage as the envelope detector. The whole tag chip is implemented in a 0.18 μm CMOS process with a die size of 880 × 950 μm 2 . Measurement results show that the rectifier achieves a maximum PCE of 53.7% with 80 kΩ resistor load. (semiconductor integrated circuits)

  17. Iodine 125 Brachytherapy With Vitrectomy and Silicone Oil in the Treatment of Uveal Melanoma: 1-to-1 Matched Case-Control Series

    International Nuclear Information System (INIS)

    McCannel, Tara A.; McCannel, Colin A.

    2014-01-01

    Purpose: We initially reported the radiation-attenuating effect of silicone oil 1000 centistokes for iodine 125. The purpose of this report was to compare the clinical outcomes in case patients who had iodine 125 brachytherapy with vitrectomy and silicone oil 1000 centistokes with the outcomes in matched control patients who underwent brachytherapy alone. Methods and Materials: Consecutive patients with uveal melanoma who were treated with iodine 125 plaque brachytherapy and vitrectomy with silicone oil with minimum 1-year follow-up were included. Control patients who underwent brachytherapy alone were matched for tumor size, location, and sex. Baseline patient and tumor characteristics and tumor response to radiation, final visual acuity, macular status, central macular thickness by ocular coherence tomography (OCT), cataract progression, and metastasis at last follow-up visit were compared. Surgical complications were also determined. Results: Twenty case patients met the inclusion criteria. The average follow-up time was 22.1 months in case patients and 19.4 months in control patients. The final logMAR vision was 0.81 in case patients and 1.1 in control patients (P=.071); 8 case patients and 16 control patients had abnormal macular findings (P=.011); and the average central macular thickness by OCT was 293.2 μm in case patients and 408.5 μm in control patients (P=.016). Eleven case patients (55%) and 1 control patient (5%) had required cataract surgery at last follow-up (P=.002). Four patients in the case group and 1 patient in the control group experienced metastasis (P=.18). Among the cases, intraoperative retinal tear occurred in 3 patients; total serous retinal detachment and macular hole developed in 1 case patient each. There was no case of rhegmatogenous retinal detachment, treatment failure, or local tumor dissemination in case patients or control patients. Conclusions: With up to 3 years of clinical follow-up, silicone oil during brachytherapy

  18. Iodine 125 Brachytherapy With Vitrectomy and Silicone Oil in the Treatment of Uveal Melanoma: 1-to-1 Matched Case-Control Series

    Energy Technology Data Exchange (ETDEWEB)

    McCannel, Tara A., E-mail: TMcCannel@jsei.ucla.edu; McCannel, Colin A.

    2014-06-01

    Purpose: We initially reported the radiation-attenuating effect of silicone oil 1000 centistokes for iodine 125. The purpose of this report was to compare the clinical outcomes in case patients who had iodine 125 brachytherapy with vitrectomy and silicone oil 1000 centistokes with the outcomes in matched control patients who underwent brachytherapy alone. Methods and Materials: Consecutive patients with uveal melanoma who were treated with iodine 125 plaque brachytherapy and vitrectomy with silicone oil with minimum 1-year follow-up were included. Control patients who underwent brachytherapy alone were matched for tumor size, location, and sex. Baseline patient and tumor characteristics and tumor response to radiation, final visual acuity, macular status, central macular thickness by ocular coherence tomography (OCT), cataract progression, and metastasis at last follow-up visit were compared. Surgical complications were also determined. Results: Twenty case patients met the inclusion criteria. The average follow-up time was 22.1 months in case patients and 19.4 months in control patients. The final logMAR vision was 0.81 in case patients and 1.1 in control patients (P=.071); 8 case patients and 16 control patients had abnormal macular findings (P=.011); and the average central macular thickness by OCT was 293.2 μm in case patients and 408.5 μm in control patients (P=.016). Eleven case patients (55%) and 1 control patient (5%) had required cataract surgery at last follow-up (P=.002). Four patients in the case group and 1 patient in the control group experienced metastasis (P=.18). Among the cases, intraoperative retinal tear occurred in 3 patients; total serous retinal detachment and macular hole developed in 1 case patient each. There was no case of rhegmatogenous retinal detachment, treatment failure, or local tumor dissemination in case patients or control patients. Conclusions: With up to 3 years of clinical follow-up, silicone oil during brachytherapy

  19. The fabrication of highly ordered block copolymer micellar arrays: control of the separation distances of silicon oxide dots

    Science.gov (United States)

    Yoo, Hana; Park, Soojin

    2010-06-01

    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.

  20. The fabrication of highly ordered block copolymer micellar arrays: control of the separation distances of silicon oxide dots

    Energy Technology Data Exchange (ETDEWEB)

    Yoo, Hana; Park, Soojin, E-mail: spark@unist.ac.kr [Interdisciplinary School of Green Energy, Ulsan National Institute of Science and Technology, Banyeon-ri 100, Ulsan 689-798 (Korea, Republic of)

    2010-06-18

    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 x 5 cm.

  1. Development of controlled release silicone adhesive–based mupirocin patch demonstrates antibacterial activity on live rat skin against Staphylococcus aureus

    Directory of Open Access Journals (Sweden)

    David SR

    2018-03-01

    Full Text Available Sheba R David,1 Nurafiqah Malek,1 Abdul Hanif Mahadi,2 Srikumar Chakravarthi,3 Rajan Rajabalaya1 1PAPRSB Institute of Health Sciences, Universiti Brunei Darussalam, Bandar Seri Begawan, Brunei Darussalam; 2Centre for Advanced Material and Energy Sciences (CAMES, Universiti Brunei Darussalam, Bandar Seri Begawan, Brunei Darussalam; 3School of Medicine, Perdana University, Jalan MAEPS Perdana, Serdang, Selangor, Malaysia Background: Peritonitis is the most serious complication of peritoneal dialysis. Staphylococcus aureus infections could lead to peritonitis which causes reversal of peritoneal dialysis treatment back to hemodialysis. The aim of this study was to develop a controlled release silicone adhesive-based mupirocin patch for prophylactic effect and analyze its antibacterial effectiveness against S. aureus.Methods: The matrix patches were prepared by using different polymers, with and without silicone adhesive, dibutyl sebacate and mupirocin. The patches were characterized for mechanical properties, drug content, moisture content, water absorption capacity and Fourier transform infrared spectrum. In vitro release studies were performed by using Franz diffusion cell. In vitro disk diffusion assay was performed on the Mueller–Hinton Agar plate to measure the zone of inhibition of the patches. The in vivo study was performed on four groups of rats with bacterial counts at three different time intervals, along with skin irritancy and histopathologic studies. Results: The patches showed appropriate average thickness (0.63–1.12 mm, tensile strength (5.08–10.08 MPa and modulus of elasticity (21.53–42.19 MPa. The drug content ranged from 94.5% to 97.4%, while the moisture content and water absorption capacities at two relative humidities (75% and 93% were in the range of 1.082–3.139 and 1.287–4.148 wt%, respectively. Fourier transform infrared spectra showed that there were no significant interactions between the polymer and the drug

  2. Polycrystalline silicon availability for photovoltaic and semiconductor industries

    Science.gov (United States)

    Ferber, R. R.; Costogue, E. N.; Pellin, R.

    1982-01-01

    Markets, applications, and production techniques for Siemens process-produced polycrystalline silicon are surveyed. It is noted that as of 1982 a total of six Si materials suppliers were servicing a worldwide total of over 1000 manufacturers of Si-based devices. Besides solar cells, the Si wafers are employed for thyristors, rectifiers, bipolar power transistors, and discrete components for control systems. An estimated 3890 metric tons of semiconductor-grade polycrystalline Si will be used in 1982, and 6200 metric tons by 1985. Although the amount is expected to nearly triple between 1982-89, research is being carried out on the formation of thin films and ribbons for solar cells, thereby eliminating the waste produced in slicing Czolchralski-grown crystals. The free-world Si production in 1982 is estimated to be 3050 metric tons. Various new technologies for the formation of polycrystalline Si at lower costs and with less waste are considered. New entries into the industrial Si formation field are projected to produce a 2000 metric ton excess by 1988.

  3. Research and development of photovoltaic power system. Characterization and control of surface/interface recombination velocity of crystalline silicon thin films; Taiyoko hatsuden system no kenkyu kaihatsu. Silicon kessho usumaku ni okeru hyomen kaimen saiketsugo sokudo no hyoka to seigyo

    Energy Technology Data Exchange (ETDEWEB)

    Hasegawa, H [Hokkaido University, Sapporo (Japan). Faculty of Engineering

    1994-12-01

    This paper reports the result obtained during fiscal 1994 on characterization and control of surface/interface recombination velocity of crystalline silicon thin films. To optimize design and manufacture of solar cells, it is necessary to identify correctly resistance factor (or doping) of bulk of materials, bulk minority carrier life, and recombination velocity on surface, passivation interface and electrode interface. A group in the Hokkaido University has been working since a few years ago on development of non-contact and non-destructive photo-luminescence surface level spectroscopy (PLS{sup 3}). A new non-contact C-V method was also introduced. Using these methods, basic discussions were given on possibility of separate measurements on surface/interface and bulk characteristics of solar cell materials. The PLS{sup 3} method and the non-contact C-V method were used for experimental discussions on evaluation of silicon mono-crystalline and poly-crystalline materials. Discussions were given on separate evaluations by using the DLTS method. 10 figs., 2 tabs.

  4. Slope stability of rectify coal waste embankments on mining areas

    International Nuclear Information System (INIS)

    Klossek, C.

    1999-01-01

    The paper is of a theoretical and experimental character, focusing on the results of field tests on the load-bearing capacity and stability of high (> 20m.) transportation embankments rectified with coal waste. The embankments are located in industrial areas subjected to the intense impact of underground mining. Such phenomena are also accompanied by essential changes in the water conditions of the subsoil. The results of model tests by SIR geo-radar used to non-damaging estimation of the suffusion occurring in the embankment constructed on non-waste materials are discussed. The numerical assessment of the filtration process has been based on the MFE and MBE programs, which are extended calculation procedures enabling the overall estimation of the redistribution of all the stress-strain components in the structure, in consideration of any hypothesis of the boundary state

  5. Creation of anticorrosion coatings for contact devices of rectifying columns

    Directory of Open Access Journals (Sweden)

    KATAMANOV Vladimir Leonidovich

    2018-02-01

    Full Text Available Today the main corrosion protection methods applied in contact devices of rectifying oil processing equipment, in particular, in mesh nozzles made of stainless steel, under relatively high temperatures (150–250оC and in the presence of aggressive components in oil raw materials (hydrogen sulfide, sulfides, mercaptans, other sulphurous compounds, chloride ions, organochlorine connections, water are to use special alloys as protecting covers as well as corrosion inhibitors that reduce corrosion action of hostile environment. At the same time, the disadvantages of the majority of these methods concern high operational costs, insufficient efficiency or protection ability designed only for a certain factor, but not for combination of them. In this regard corrosion resistance of mesh contact devices made of stainless steel (brand SUS 321 has been studied on three types of samples: alloy wire, welded grid, thin leaf. Titanium nitride (TiN and metallic coatings from nickel (Ni, titanium (Ti and chrome (Cr were used as anticorrosion coatings for the mentioned samples. These coverings were applied on samples in two ways: by means of electrolytic method and vacuum ion-plasma dusting. It was determined that optimal coating thickness is 10–15 microns as it is the thickness at which the produced films possess sufficient plasticity and do not exfoliate from the surface of the corresponding corrosion-proof alloy. The research of corrosion of samples of stainless steel SUS 321 with applied coverings and without them was performed by immersing the samples into compositions that contain oil as well as into the modeling hostile oil-containing environment. As a result of the conducted researches it was determined that the protecting covers of chrome and titanium nitride applied with vacuum ion-plasma dusting method are the most effective coatings from the point of view of anticorrosive protection for mesh contact devices of stainless steel used in rectifying

  6. New filter media development for effective control of trimethysilanol (TMS) and related low molecular weight silicon containing organic species in the photobay ambient

    Science.gov (United States)

    Grayfer, Anatoly; Belanger, Frank V.; Cate, Phillip; Ruede, David

    2007-03-01

    The authors present results of extensive studies on the chemical behavior of low molecular weight silicon-containing species (LMWS) and associated challenges of their analytical determination and control to prevent adverse influence on critical optical elements of exposure tools. In their paper the authors describe a non-traditional approach to the creation of a TMS gaseous source for filter media development and an engineering solution to the challenge of controlling LMWS - a solution that shows a significant advantage over currently existing approaches.

  7. Characterization of the chicken inward rectifier K+ channel IRK1/Kir2.1 gene

    Directory of Open Access Journals (Sweden)

    Locke Emily

    2004-11-01

    Full Text Available Abstract Background Inward rectifier potassium channels (IRK contribute to the normal function of skeletal and cardiac muscle cells. The chick inward rectifier K+ channel cIRK1/Kir2.1 is expressed in skeletal muscle, heart, brain, but not in liver; a distribution similar but not identical to that of mouse Kir2.1. We set out to explore regulatory domains of the cIRK1 promoter that enhance or inhibit expression of the gene in different cell types. Results We cloned and characterized the 5'-flanking region of cIRK1. cIRK1 contains two exons with splice sites in the 5'-untranslated region, a structure similar to mouse and human orthologs. cIRK1 has multiple transcription initiation sites, a feature also seen in mouse. However, while the chicken and mouse promoter regions share many regulatory motifs, cIRK1 possesses a GC-richer promoter and a putative TATA box, which appears to positively regulate gene expression. We report here the identification of several candidate cell/tissue specific cIRK1 regulatory domains by comparing promoter activities in expressing (Qm7 and non-expressing (DF1 cells using in vitro transcription assays. Conclusion While multiple transcription initiation sites and the combinatorial function of several domains in activating cIRK1 expression are similar to those seen in mKir2.1, the cIRK1 promoter differs by the presence of a putative TATA box. In addition, several domains that regulate the gene's expression differentially in muscle (Qm7 and fibroblast cells (DF1 were identified. These results provide fundamental data to analyze cIRK1 transcriptional mechanisms. The control elements identified here may provide clues to the tissue-specific expression of this K+ channel.

  8. A 50–60 GHz mm-wave rectifier with bulk voltage bias in 65-nm CMOS

    NARCIS (Netherlands)

    Gao, H.; Matters-Kammerer, M.; Harpe, P.; Baltus, P.

    2016-01-01

    This letter presents a 50∼60 GHz fully integrated 3-stage rectifier with bulk voltage bias for threshold voltage modulation in a 65-nm CMOS technology, which can be integrated in a mm-wave hybrid rectifier structure as the main rectifier. In this letter, the new technique of bulk voltage bias is

  9. 75 FR 24747 - SCI, LLC/Zener-Rectifier Operations Division A Wholly Owned Subsidiary of SCI, LLC/ON...

    Science.gov (United States)

    2010-05-05

    ... DEPARTMENT OF LABOR Employment and Training Administration [TA-W-70,235] SCI, LLC/Zener-Rectifier... Adjustment Assistance on October 19, 2009, applicable to workers of SCI LLC/Zener-Rectifier, Operations... Technical Resources were employed on-site at the Phoenix Arizona location of SCI LLC/Zener-Rectifier...

  10. Silicon graphene Bragg gratings.

    Science.gov (United States)

    Capmany, José; Domenech, David; Muñoz, Pascual

    2014-03-10

    We propose the use of interleaved graphene sections on top of a silicon waveguide to implement tunable Bragg gratings. The filter central wavelength and bandwidth can be controlled changing the chemical potential of the graphene sections. Apodization techniques are also presented.

  11. Development of an In-Line Minority-Carrier Lifetime Monitoring Tool for Process Control during Fabrication of Crystalline Silicon Solar Cells: Annual Subcontract Report, June 2003 (Revised)

    Energy Technology Data Exchange (ETDEWEB)

    Sinton, R. A.

    2004-04-01

    Under the PV Manufacturing R&D subcontract''Development of an In-Line, Minority-Carrier Lifetime Monitoring Tool for Process Control during Fabrication of Crystalline Silicon Solar Cells'', Sinton Consulting developed prototypes for several new instruments for use in the manufacture of silicon solar cells. These instruments are based on two families of R&D instruments that were previously available, an illumination vs. open-circuit-voltage technique and the quasi-steady state RF photoconductance technique for measuring minority-carrier lifetime. Compared to the previous instruments, the new prototypes are about 20 times faster per measurement, and have automated data analysis that does not require user intervention even when confronted by challenging cases. For example, un-passivated multi-crystalline wafers with large variations in lifetime and trapping behavior can be measured sequentially without error. Five instruments have been prototyped in this project to date, including a block tester for evaluating cast or HEM silicon blocks, a CZ ingot tester, an FZ boule tester for use with long-lifetime silicon, and an in-line sample head for measuring wafers. The CZ ingot tester and the FZ boule tester are already being used within industry and there is interest in the other prototypes. For each instrument, substantial R&D work was required in developing the device physics and analysis as well as for the hardware. This work has been documented in a series of application notes and conference publications, and will result in significant improvements for both the R&D and the industrial types of instruments.

  12. 3-D printed 2.4 GHz rectifying antenna for wireless power transfer applications

    Science.gov (United States)

    Skinner, Matthew

    In this work, a 3D printed rectifying antenna that operates at the 2.4GHz WiFi band was designed and manufactured. The printed material did not have the same properties of bulk material, so the printed materials needed to be characterized. The antenna and rectifying circuit was printed out of Acrylonitrile Butadiene Styrene (ABS) filament and a conductive silver paste, with electrical components integrated into the circuit. Before printing the full rectifying antenna, each component was printed and evaluated. The printed antenna operated at the desired frequency with a return loss of -16 dBm with a bandwidth of 70MHz. The radiation pattern was measured in an anechoic chamber with good matching to the model. The rectifying circuit was designed in Ansys Circuit Simulation using Schottky diodes to enable the circuit to operate at lower input power levels. Two rectifying circuits were manufactured, one by printing the conductive traces with silver ink, and one with traces made from copper. The printed silver ink is less conductive than the bulk copper and therefore the output voltage of the printed rectifier was lower than the copper circuit. The copper circuit had an efficiency of 60% at 0dBm and the printed silver circuit had an efficiency of 28.6% at 0dBm. The antenna and rectifying circuits were then connected to each other and the performance was compared to a fully printed integrated rectifying antenna. The rectifying antennas were placed in front of a horn antenna while changing the power levels at the antenna. The efficiency of the whole system was lower than the individual components but an efficiency of 11% at 10dBm was measured.

  13. Silicon-micromachined microchannel plates

    CERN Document Server

    Beetz, C P; Steinbeck, J; Lemieux, B; Winn, D R

    2000-01-01

    Microchannel plates (MCP) fabricated from standard silicon wafer substrates using a novel silicon micromachining process, together with standard silicon photolithographic process steps, are described. The resulting SiMCP microchannels have dimensions of approx 0.5 to approx 25 mu m, with aspect ratios up to 300, and have the dimensional precision and absence of interstitial defects characteristic of photolithographic processing, compatible with positional matching to silicon electronics readouts. The open channel areal fraction and detection efficiency may exceed 90% on plates up to 300 mm in diameter. The resulting silicon substrates can be converted entirely to amorphous quartz (qMCP). The strip resistance and secondary emission are developed by controlled depositions of thin films, at temperatures up to 1200 deg. C, also compatible with high-temperature brazing, and can be essentially hydrogen, water and radionuclide-free. Novel secondary emitters and cesiated photocathodes can be high-temperature deposite...

  14. Detection of vortex-core dynamics using current-induced self-bistable rectifying effect

    International Nuclear Information System (INIS)

    Goto, M; Hata, H; Yamaguchi, A; Miyajima, H; Nozaki, Y; Nakatani, Y; Yamaoka, T

    2011-01-01

    A magnetic vortex core confined in a micron-scale magnetic disk is resonantly excited by spin-polarized radio-frequency (rf) current and rf field. We show that rectifying voltage spectra caused by the vortex core resonance is dependent on the core polarity. Rectifying voltage spectra are given by the superposition of the polarity-dependent term and the polarity-independent term. The sign of the polarity-dependent rectifying voltage reverses when the sign of polarity P or external field H is reversed. This experimental result can be explained by the anisotropic magnetoresistance effect caused by the vortex core motion.

  15. A Theoretical Investigation on Rectifying Performance of a Single Motor Molecular Device

    International Nuclear Information System (INIS)

    Lei Hui; Tan Xun-Qiong

    2015-01-01

    We report ab initio calculations of the transport behavior of a phenyl substituted molecular motor. The calculated results show that the transport behavior of the device is sensitive to the rotation degree of the rotor part. When the rotor part is parallel with the stator part, a better rectifying performance can be found in the current-voltage curve. However, when the rotor part revolves to vertical with the stator part, the currents in the positive bias region decrease slightly. More importantly, the rectifying performance disappears. Thus this offers us a new method to modulate the rectifying behavior in molecular devices. (condensed matter: electronic structure, electrical, magnetic, and optical properties)

  16. Rectifying Properties of a Nitrogen/Boron-Doped Capped-Carbon-Nanotube-Based Molecular Junction

    International Nuclear Information System (INIS)

    Zhao Peng; Zhang Ying; Wang Pei-Ji; Zhang Zhong; Liu De-Sheng

    2011-01-01

    Based on the non-equilibrium Green's function method and first-principles density functional theory calculations, we investigate the electronic transport properties of a nitrogen/boron-doped capped-single-walled carbon-nanotube-based molecular junction. Obvious rectifying behavior is observed and it is strongly dependent on the doping site. The best rectifying performance can be carried out when the nitrogen/boron atom dopes at a carbon site in the second layer. Moreover, the rectifying performance can be further improved by adjusting the distance between the C 60 nanotube caps. (condensed matter: electronic structure, electrical, magnetic, and optical properties)

  17. Tunable all-optical plasmonic rectifier in nanoscale metal-insulator-metal waveguides.

    Science.gov (United States)

    Xu, Yi; Wang, Xiaomeng; Deng, Haidong; Guo, Kangxian

    2014-10-15

    We propose a tunable all-optical plasmonic rectifier based on the nonlinear Fano resonance in a metal-insulator-metal plasmonic waveguide and cavities coupling system. We develop a theoretical model based on the temporal coupled-mode theory to study the device physics of the nanoscale rectifier. We further demonstrate via the finite difference time domain numerical experiment that our idea can be realized in a plasmonic system with an ultracompact size of ~120×800  nm². The tunable plasmonic rectifier could facilitate the all-optical signal processing in nanoscale.

  18. Current and Voltage Conveyors in Current- and Voltage-Mode Precision Full-Wave Rectifiers

    Directory of Open Access Journals (Sweden)

    J. Koton

    2011-04-01

    Full Text Available In this paper new versatile precision full-wave rectifiers using current and/or voltage conveyors as active elements and two diodes are presented. The performance of these circuit solutions is analysed and compared to the opamp based precision rectifier. To analyze the behavior of the functional blocks, the frequency dependent RMS error and DC transient value are evaluated for different values of input voltage amplitudes. Furthermore, experimental results are given that show the feasibilities of the conveyor based rectifiers superior to the corresponding operational amplifier based topology.

  19. An RF energy harvester system using UHF micropower CMOS rectifier based on a diode connected CMOS transistor.

    Science.gov (United States)

    Shokrani, Mohammad Reza; Khoddam, Mojtaba; Hamidon, Mohd Nizar B; Kamsani, Noor Ain; Rokhani, Fakhrul Zaman; Shafie, Suhaidi Bin

    2014-01-01

    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  μm 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 μm TSMC CMOS technology.

  20. Intermediate Bandgap Solar Cells From Nanostructured Silicon

    Energy Technology Data Exchange (ETDEWEB)

    Black, Marcie [Bandgap Engineering, Lincoln, MA (United States)

    2014-10-30

    This project aimed to demonstrate increased electronic coupling in silicon nanostructures relative to bulk silicon for the purpose of making high efficiency intermediate bandgap solar cells using silicon. To this end, we formed nanowires with controlled crystallographic orientation, small diameter, <111> sidewall faceting, and passivated surfaces to modify the electronic band structure in silicon by breaking down the symmetry of the crystal lattice. We grew and tested these silicon nanowires with <110>-growth axes, which is an orientation that should produce the coupling enhancement.

  1. Design and modelling of a silicon optical MEMS switch controlled by magnetic field generated by a plain coil

    International Nuclear Information System (INIS)

    Golebiowski, J; Milcarz, Sz

    2014-01-01

    Optical switches can be made as a silicon cantilever with a magnetic layer. Such a structure is placed in a magnetic field of a planar coil. There is a torque deflecting the silicon beam with NiFe layer depending on a flux density of the magnetic field. The study shows an analysis of ferromagnetic layer parameters, beam's dimensions on optical switch characteristics. Different constructions of the beams were simulated for a range of values of magnetic field strength from 100 to 1000 A/m. An influence of the actuators parameters on characteristics was analysed. The loss of stiffness of the beam caused by specific constructions effected in displacements reaching 85 nm. Comsol Multiphysics 4.3b was used for the simulations.

  2. Use of hydroxypropylmethylcellulose 2% for removing adherent silicone oil from silicone intraocular lenses

    OpenAIRE

    Wong , S Chien; Ramkissoon , Yashin D; Lopez , Mauricio; Page , Kristopher; Parkin , Ivan P; Sullivan , Paul M

    2009-01-01

    Abstract Background / aims: To investigate the effect of hydroxypropylmethylcellulose (HPMC) on the physical interaction (contact angle) between silicone oil and a silicone intraocular lens (IOL). Methods: In vitro experiments were performed, to determine the effect of HPMC (0.5%, 1% or 2%), with or without an additional simple mechanical manoeuvre, on the contact angle of silicone oil at the surface of both silicone and acrylic (control) IOLs. A balanced salt solu...

  3. Inhibitory Effect of Vascular Endothelial Growth Factor on the Slowly Activating Delayed Rectifier Potassium Current in Guinea Pig Ventricular Myocytes.

    Science.gov (United States)

    Lin, Zhenhao; Xing, Wenlu; Gao, Chuanyu; Wang, Xianpei; Qi, Datun; Dai, Guoyou; Zhao, Wen; Yan, Ganxin

    2018-01-26

    Vascular endothelial growth factor (VEGF) exerts a number of beneficial effects on ischemic myocardium via its angiogenic properties. However, little is known about whether VEGF has a direct effect on the electrical properties of cardiomyocytes. In the present study, we investigated the effects of different concentrations of VEGF on delayed rectifier potassium currents (I K ) in guinea pig ventricular myocytes and their effects on action potential (AP) parameters. I K and AP were recorded by the whole-cell patch clamp method in ventricular myocytes. Cells were superfused with control solution or solution containing VEGF at different concentrations for 10 minutes before recording. Some ventricular myocytes were pretreated with a phosphatidylinositol 3-kinase inhibitor for 1 hour before the addition of VEGF. We found that VEGF inhibited the slowly activating delayed rectifier potassium current (I K s ) in a concentration-dependent manner (18.13±1.04 versus 12.73±0.34, n=5, P =0.001; 12.73±0.34 versus 9.05±1.20, n=5, P =0.036) and prolonged AP duration (894.5±36.92 versus 746.3±33.71, n=5, P =0.021). Wortmannin, a phosphatidylinositol 3-kinase inhibitor, eliminated these VEGF-induced effects. VEGF had no significant effect on the rapidly activating delayed rectifier potassium current (I K r ), resting membrane potential, AP amplitude, or maximal velocity of depolarization. VEGF inhibited I K s in a concentration-dependent manner through a phosphatidylinositol 3-kinase-mediated signaling pathway, leading to AP prolongation. The results indicate a promising therapeutic potential of VEGF in prevention of ventricular tachyarrhythmias under conditions of high sympathetic activity and ischemia. © 2018 The Authors. Published on behalf of the American Heart Association, Inc., by Wiley.

  4. Terahertz Detection and Imaging Using Graphene Ballistic Rectifiers.

    Science.gov (United States)

    Auton, Gregory; But, Dmytro B; Zhang, Jiawei; Hill, Ernie; Coquillat, Dominique; Consejo, Christophe; Nouvel, Philippe; Knap, Wojciech; Varani, Luca; Teppe, Frederic; Torres, Jeremie; Song, Aimin

    2017-11-08

    A graphene ballistic rectifier is used in conjunction with an antenna to demonstrate a rectenna as a terahertz (THz) detector. A small-area (<1 μm 2 ) local gate is used to adjust the Fermi level in the device to optimize the output while minimizing the impact on the cutoff frequency. The device operates in both n- and p-type transport regimes and shows a peak extrinsic responsivity of 764 V/W and a corresponding noise equivalent power of 34 pW Hz -1/2 at room temperature with no indications of a cutoff frequency up to 0.45 THz. The device also demonstrates a linear response for more than 3 orders of magnitude of input power due to its zero threshold voltage, quadratic current-voltage characteristics and high saturation current. Finally, the device is used to take an image of an optically opaque object at 0.685 THz, demonstrating potential in both medical and security imaging applications.

  5. Graphene ballistic nano-rectifier with very high responsivity

    Science.gov (United States)

    Auton, Gregory; Zhang, Jiawei; Kumar, Roshan Krishna; Wang, Hanbin; Zhang, Xijian; Wang, Qingpu; Hill, Ernie; Song, Aimin

    2016-01-01

    Although graphene has the longest mean free path of carriers of any known electronic material, very few novel devices have been reported to harness this extraordinary property. Here we demonstrate a ballistic nano-rectifier fabricated by creating an asymmetric cross-junction in single-layer graphene sandwiched between boron nitride flakes. A mobility ∼200,000 cm2 V−1 s−1 is achieved at room temperature, well beyond that required for ballistic transport. This enables a voltage responsivity as high as 23,000 mV mW−1 with a low-frequency input signal. Taking advantage of the output channels being orthogonal to the input terminals, the noise is found to be not strongly influenced by the input. Hence, the corresponding noise-equivalent power is as low as 0.64 pW Hz−1/2. Such performance is even comparable to superconducting bolometers, which however need to operate at cryogenic temperatures. Furthermore, output oscillations are observed at low temperatures, the period of which agrees with the lateral size quantization. PMID:27241162

  6. Finite element modeling of electrically rectified piezoelectric energy harvesters

    International Nuclear Information System (INIS)

    Wu, P H; Shu, Y C

    2015-01-01

    Finite element models are developed for designing electrically rectified piezoelectric energy harvesters. They account for the consideration of common interface circuits such as the standard and parallel-/series-SSHI (synchronized switch harvesting on inductor) circuits, as well as complicated structural configurations such as arrays of piezoelectric oscillators. The idea is to replace the energy harvesting circuit by the proposed equivalent load impedance together with the capacitance of negative value. As a result, the proposed framework is capable of being implemented into conventional finite element solvers for direct system-level design without resorting to circuit simulators. The validation based on COMSOL simulations carried out for various interface circuits by the comparison with the standard modal analysis model. The framework is then applied to the investigation on how harvested power is reduced due to fabrication deviations in geometric and material properties of oscillators in an array system. Remarkably, it is found that for a standard array system with strong electromechanical coupling, the drop in peak power turns out to be insignificant if the optimal load is carefully chosen. The second application is to design broadband energy harvesting by developing array systems with suitable interface circuits. The result shows that significant broadband is observed for the parallel (series) connection of oscillators endowed with the parallel-SSHI (series-SSHI) circuit technique. (paper)

  7. Finite element modeling of electrically rectified piezoelectric energy harvesters

    Science.gov (United States)

    Wu, P. H.; Shu, Y. C.

    2015-09-01

    Finite element models are developed for designing electrically rectified piezoelectric energy harvesters. They account for the consideration of common interface circuits such as the standard and parallel-/series-SSHI (synchronized switch harvesting on inductor) circuits, as well as complicated structural configurations such as arrays of piezoelectric oscillators. The idea is to replace the energy harvesting circuit by the proposed equivalent load impedance together with the capacitance of negative value. As a result, the proposed framework is capable of being implemented into conventional finite element solvers for direct system-level design without resorting to circuit simulators. The validation based on COMSOL simulations carried out for various interface circuits by the comparison with the standard modal analysis model. The framework is then applied to the investigation on how harvested power is reduced due to fabrication deviations in geometric and material properties of oscillators in an array system. Remarkably, it is found that for a standard array system with strong electromechanical coupling, the drop in peak power turns out to be insignificant if the optimal load is carefully chosen. The second application is to design broadband energy harvesting by developing array systems with suitable interface circuits. The result shows that significant broadband is observed for the parallel (series) connection of oscillators endowed with the parallel-SSHI (series-SSHI) circuit technique.

  8. 2012 NOAA Color Ortho-rectified Mosaic of Corpus Christi to Saint Charles Bay, Texas

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — This data set contains ortho-rectified mosaic tiles, created as a product from the NOAA Integrated Ocean and Coastal Mapping (IOCM) initiative. The source imagery...

  9. 2010 NOAA Ortho-rectified Mosaic from Color Aerial Imagery of LAKE CHARLES

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — This data set contains ortho-rectified mosaic tiles, created as a product from the NOAA Integrated Ocean and Coastal Mapping (IOCM) initiative of LAKE CHARLES. The...

  10. 2016 NOAA NGS Ortho-rectified Color Mosaic of Anchorage, Alaska

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — This data set contains ortho-rectified mosaic tiles, created as a product from the NOAA Integrated Ocean and Coastal Mapping (IOCM) initiative. The source imagery...

  11. 2010 NOAA Ortho-rectified Near-infrared Mosaic of Port Arthur - Beaumont, Texas

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — This data set contains ortho-rectified mosaic tiles, created as a product from the NOAA Integrated Ocean and Coastal Mapping (IOCM) initiative. The source imagery...

  12. 2010 NOAA Ortho-rectified Mosaic from Color Aerial Imagery of BEAUMONT, ORANGE, PORT AUTHUR

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — This data set contains ortho-rectified mosaic tiles, created as a product from the NOAA Integrated Ocean and Coastal Mapping (IOCM) initiative of BEAUMONT, ORANGE,...

  13. 2016 NOAA NGS Ortho-rectified Near-Infrared Mosaic of Cleveland, Ohio

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — This data set contains ortho-rectified mosaic tiles, created as a product from the NOAA Integrated Ocean and Coastal Mapping (IOCM) initiative. The source imagery...

  14. 2010 NOAA Ortho-rectified Mosaic from Color Aerial Imagery of CHOCTAWHATCHEE BAY

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — This data set contains ortho-rectified mosaic tiles, created as a product from the NOAA Integrated Ocean and Coastal Mapping (IOCM) initiative of CHOCTAWHATCHEE BAY....

  15. 2010 NOAA Ortho-rectified Mosaic from Color Aerial Imagery of LAKE CHARLES (NODC Accession 0075827)

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — This data set contains ortho-rectified mosaic tiles, created as a product from the NOAA Integrated Ocean and Coastal Mapping (IOCM) initiative of LAKE CHARLES. The...

  16. 2014 NOAA Ortho-rectified Mosaic of Delaware Coastline: Hurricane Sandy Impact Area

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — This data set contains ortho-rectified mosaic tiles at 0.10m GSD. This data set was created for NOAA Integrated Ocean and Coastal Mapping (IOCM) initiative in the...

  17. 2010 NOAA Ortho-rectified Mosaic from Color Aerial Imagery of MISSISSIPPI RIVER - LAPLACE TO VENICE

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — This data set contains ortho-rectified mosaic tiles, created as a product from the NOAA Integrated Ocean and Coastal Mapping (IOCM) initiative of MISSISSIPPI RIVER -...

  18. 2012 NOAA Ortho-rectified Color MLLW Mosaic of Alabama: Eastern Mississippi Sound

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — This data set contains ortho-rectified mosaic tiles, created as a product from the NOAA Integrated Ocean and Coastal Mapping (IOCM) initiative. The source imagery...

  19. 2015 NOAA Ortho-rectified Near-Infrared Mosaic of the port of Silver Bay, Minnesota

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — This data set contains ortho-rectified mosaic tiles, created as a product from the NOAA Integrated Ocean and Coastal Mapping (IOCM) initiative. The source imagery...

  20. 2015 NOAA Ortho-rectified Color Mosaic of the port of Silver Bay, Minnesota

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — This data set contains ortho-rectified mosaic tiles, created as a product from the NOAA Integrated Ocean and Coastal Mapping (IOCM) initiative. The source imagery...

  1. 2012 NOAA Ortho-rectified Color MLLW Mosaic of Pescadero Point to Bodega Bay, California

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — This data set contains ortho-rectified mosaic tiles, created as a product from the NOAA Integrated Ocean and Coastal Mapping (IOCM) initiative. The source imagery...

  2. 2012 NOAA Ortho-rectified Near-Infrared Mosaic of Oregon: Lake Umatilla to Clarkson

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — This data set contains ortho-rectified mosaic tiles, created as a product from the NOAA Integrated Ocean and Coastal Mapping (IOCM) initiative. The source imagery...

  3. 2011 NOAA Ortho-rectified Mosaic of Intracoastal City, Louisiana (NODC Accession 0075831)

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — This data set contains ortho-rectified mosaic tiles, created as a product from the NOAA Integrated Ocean and Coastal Mapping (IOCM) initiative. The source imagery...

  4. 2010 NOAA Ortho-rectified Mosaic of Savannah River, Georgia (NODC Accession 0092435)

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — This data set contains ortho-rectified mosaic tiles, created as a product from the NOAA Integrated Ocean and Coastal Mapping (IOCM) initiative. The source imagery...

  5. 2011 NOAA Ortho-rectified Mosaic of Tallaboa, Puerto Rico (NODC Accession 0074381)

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — This data set contains ortho-rectified mosaic tiles, created as a product from the NOAA Integrated Ocean and Coastal Mapping (IOCM) initiative. The source imagery...

  6. Positive Temperature Coefficient of Breakdown Voltage in 4H-SiC PN Junction Rectifiers

    National Research Council Canada - National Science Library

    Neudeck, Philip

    1998-01-01

    ...-suited SiC polytype for power device implementation. This paper reports the first experimental measurements of stable positive temperature coefficient behavior observed in 4H-SiC pn junction rectifiers...

  7. Influence of load type on power factor and harmonic composition of three-phase rectifier current

    Science.gov (United States)

    Nikolayzin, N. V.; Vstavskaya, E. V.; Konstantinov, V. I.; Konstantinova, O. V.

    2018-05-01

    This article is devoted to research of the harmonic composition of the three-phase rectifier current consumed when it operates with different types of load. The results are compared with Standard requirements.

  8. 2016 NOAA NGS Ortho-rectified Color Mosaic of Whittier, Alaska

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — This data set contains ortho-rectified mosaic tiles, created as a product from the NOAA Integrated Ocean and Coastal Mapping (IOCM) initiative. The source imagery...

  9. 2012 NOAA Ortho-rectified Near-Infrared MLLW Mosaic of Alabama: Eastern Mississippi Sound

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — This data set contains ortho-rectified mosaic tiles, created as a product from the NOAA Integrated Ocean and Coastal Mapping (IOCM) initiative. The source imagery...

  10. A novel approach to determine the interphase transformer inductance of 18 pulse rectifiers

    International Nuclear Information System (INIS)

    Sefa, Ibrahim; Altin, Necmi

    2009-01-01

    The interphase transformer inductance seriously affects the performance of 18 pulse rectifiers. Low inductance values cause non-characteristic harmonics whereas high inductance values increase the rectifier cost and size. Hence, determination of the interphase transformer inductance value is an important problem in the design of 18 pulse rectifiers. In this paper, an approach to determine the optimum inductance value of an interphase transformer is proposed and a practical formula is introduced. The proposed approach has been validated with simulation and experimental studies carried out with designed capacitive loaded autotransformer based 18 pulse rectifier for different IPT inductance values at different load levels. Experimental and simulation results show that cost effective interphase transformer inductance value can be determined with the proposed approach and this value reduces the line current harmonics and improves power factor drastically.

  11. The energizing of a NMR superconducting coil by a superconducting rectifier

    International Nuclear Information System (INIS)

    Sikkenga, J.; ten Kate, H.H.J.; van der Klundert, L.J.M.; Knoben, J.; Kraaij, G.J.; Spuorenberg, C.J.G.

    1985-01-01

    NMR magnets require a good homogeneity within a certain volume and an excellent field stability. The homogeneity can be met using a superconducting shim coil system. The field stability requires a constant current, although in many cases the current decay time constant is too low, due to imperfections in the superconducting wire and joints. This can be overcome using a rectifier. The rectifier can also be used to load the coil. The combination and interaction of the superconducting NMR coil (2.0 Tesla and 0.35 m cold bore) and the rectifier (20 W / 1 kA) is tested. The safety of the system is discussed. The shim coil system can compensate the strayfield of the rectifier. The field decay compensation will be discussed

  12. 2013 NOAA Ortho-rectified Color Mosaic of California: Port of San Diego

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — This data set contains ortho-rectified mosaic tiles, created as a product from the NOAA Integrated Ocean and Coastal Mapping (IOCM) initiative. The source imagery...

  13. 2013 NOAA Ortho-rectified Color Mosaic of Intercoastal Waterway - Calcasieu Lake to Vermillion Bay, Louisiana

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — This data set contains ortho-rectified mosaic tiles, created as a product from the NOAA Integrated Ocean and Coastal Mapping (IOCM) initiative. The source imagery...

  14. 2012 NOAA Ortho-rectified Color MLLW Mosaic of Bodega Bay to Shelter Cove, California

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — This data set contains ortho-rectified mosaic tiles, created as a product from the NOAA Integrated Ocean and Coastal Mapping (IOCM) initiative. The source imagery...

  15. 2017 NOAA NGS Ortho-rectified Color Mosaic of Houston Ship Channel, Texas

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — This data set contains ortho-rectified mosaic tiles, created as a product from the NOAA Integrated Ocean and Coastal Mapping (IOCM) initiative. The source imagery...

  16. 2016 NOAA NGS Ortho-rectified Mean High Water Color Mosaic of Venice Inlet ICW, Florida

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — This data set contains ortho-rectified mosaic tiles, created as a product from the NOAA Integrated Ocean and Coastal Mapping (IOCM) initiative. The source imagery...

  17. 2012 NOAA Ortho-rectified Color MLLW Mosaic of Seal Rock to Lopez Rock, California

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — This data set contains ortho-rectified mosaic tiles, created as a product from the NOAA Integrated Ocean and Coastal Mapping (IOCM) initiative. The source imagery...

  18. 2011 NOAA Ortho-rectified Mosaic of Intracoastal Waterway, Texas (NODC Accession 0105604)

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — This data set contains ortho-rectified mosaic tiles, created as a product from the NOAA Integrated Ocean and Coastal Mapping (IOCM) initiative. The source imagery...

  19. 2012 NOAA Ortho-rectified Color Mosaic of Sacramento Deep Water Ship Channel, California

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — This data set contains ortho-rectified mosaic tiles, created as a product from the NOAA Integrated Ocean and Coastal Mapping (IOCM) initiative. The source imagery...

  20. 2009 NOAA Near-Infrared Ortho-rectified Mosaic of Brunswick, Georgia (NODC Accession 0092435)

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — This data set contains ortho-rectified mosaic tiles, created as a product from the NOAA Integrated Ocean and Coastal Mapping (IOCM) initiative. The source imagery...

  1. 2012 NOAA Ortho-rectified Color MHW Mosaic of Washington: Seattle and Lake Washington Ship Canal

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — This data set contains ortho-rectified mosaic tiles, created as a product from the NOAA Integrated Ocean and Coastal Mapping (IOCM) initiative. The source imagery...

  2. 2012 NOAA Ortho-rectified Color MLLW Mosaic of Lopez Rock to Pescadero Point, California

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — This data set contains ortho-rectified mosaic tiles, created as a product from the NOAA Integrated Ocean and Coastal Mapping (IOCM) initiative. The source imagery...

  3. 2012 NOAA Ortho-rectified Color Mosaic of Del Mar Boat Basin and Oceanside Harbor, California

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — This data set contains ortho-rectified mosaic tiles, created as a product from the NOAA Integrated Ocean and Coastal Mapping (IOCM) initiative. The source imagery...

  4. 2013 NOAA Ortho-rectified Near-Infrared Mosaic of the Port of Panama City, Florida

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — This data set contains ortho-rectified mosaic tiles, created as a product from the NOAA Integrated Ocean and Coastal Mapping (IOCM) initiative. The source imagery...

  5. 2016 NOAA NGS Ortho-rectified Color Mosaic of Baton Rouge, Louisiana

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — This data set contains ortho-rectified mosaic tiles, created as a product from the NOAA Integrated Ocean and Coastal Mapping (IOCM) initiative. The source imagery...

  6. 2009 NOAA Ortho-rectified RGB Mosaic of Savannah, Georgia (NODC Accession 0092435)

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — This data set contains ortho-rectified mosaic tiles, created as a product from the NOAA Integrated Ocean and Coastal Mapping (IOCM) initiative. The source imagery...

  7. 2011 NOAA Ortho-rectified Mosaic of Texas: Integrated Ocean and Coastal Mapping Product

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — This data set contains ortho-rectified mosaic tiles, created as a product from the NOAA Integrated Ocean and Coastal Mapping (IOCM) initiative. The source imagery...

  8. 2012 NOAA Color MLLW Ortho-rectified Mosaic of Amelia Island and Nassau River, Florida

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — This data set contains ortho-rectified mosaic tiles, created as a product from the NOAA Integrated Ocean and Coastal Mapping (IOCM) initiative. The source imagery...

  9. 2011 NOAA Color MHW Ortho-rectified Mosaic of Amelia Island and Nassau River, Florida

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — This data set contains ortho-rectified mosaic tiles, created as a product from the NOAA Integrated Ocean and Coastal Mapping (IOCM) initiative. The source imagery...

  10. An overview of self-switching diode rectifiers using green materials

    Science.gov (United States)

    Kasjoo, Shahrir Rizal; Zailan, Zarimawaty; Zakaria, Nor Farhani; Isa, Muammar Mohamad; Arshad, Mohd Khairuddin Md; Taking, Sanna

    2017-09-01

    A unipolar two-terminal nanodevice, known as the self-switching diode (SSD), has recently been demonstrated as a room-temperature rectifier at microwave and terahertz frequencies due to its nonlinear current-voltage characteristic. The planar architecture of SSD not only makes the fabrication process of the device faster, simpler and at a lower cost when compared with other rectifying diodes, but also allows the use of various materials to realize and fabricate SSDs. This includes the utilization of `green' materials such as organic and graphene thin films for environmental sustainability. This paper reviews the properties of current `green' SSD rectifiers with respect to their operating frequencies and rectifying performances, including responsivity and noise-equivalent power of the devices, along with the applications.

  11. 2011 NOAA Ortho-rectified Near-Infrared Mosaic of Isle of Shoals, New Hampshire (MHW)

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — This data set contains ortho-rectified mosaic tiles, created as a product from the NOAA Integrated Ocean and Coastal Mapping (IOCM) initiative. The source imagery...

  12. 2016 NOAA NGS Ortho-rectified Color Mosaic of Kenai and Nikiski, Alaska

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — This data set contains ortho-rectified mosaic tiles, created as a product from the NOAA Integrated Ocean and Coastal Mapping (IOCM) initiative. The source imagery...

  13. 2014 NOAA Ortho-rectified Mosaic of Hurricane Sandy Coastal Impact Area

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — This data set contains ortho-rectified mosaic tiles at 0.35m GSD created for NOAA Integrated Ocean and Coastal Mapping (IOCM) initiative in Hurricane Sandy coastal...

  14. 2010 NOAA Ortho-rectified Mosaic of Louisiana: Mississippi River - Baton Rouge to Southwest Pass

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — This data set contains ortho-rectified mosaic tiles, created as a product from the NOAA Integrated Ocean and Coastal Mapping (IOCM) initiative. The source imagery...

  15. 2013 NOAA Ortho-rectified Color Mosaic of California: Port of Los Angeles and Long Beach

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — This data set contains ortho-rectified mosaic tiles, created as a product from the NOAA Integrated Ocean and Coastal Mapping (IOCM) initiative. The source imagery...

  16. 2016 NOAA NGS Ortho-rectified Color Mosaic of Cleveland, Ohio

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — This data set contains ortho-rectified mosaic tiles, created as a product from the NOAA Integrated Ocean and Coastal Mapping (IOCM) initiative. The source imagery...

  17. 2015 NOAA NGS Ortho-rectified Near-Infrared Mosaic of Port Canaveral, Florida

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — This data set contains ortho-rectified mosaic tiles, created as a product from the NOAA Integrated Ocean and Coastal Mapping (IOCM) initiative. The source imagery...

  18. 2010 NOAA Ortho-rectified Mosaic of Lake Michigan - West Coast

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — This data set contains ortho-rectified mosaic tiles, created as a product from the NOAA Integrated Ocean and Coastal Mapping (IOCM) initiative. The source imagery...

  19. 2010 NOAA Ortho-rectified Mosaic from Color Aerial Imagery of PORT OF GEORGETOWN - CSCAP

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — This data set contains ortho-rectified mosaic tiles, created as a product from the NOAA Integrated Ocean and Coastal Mapping (IOCM) initiative of PORT OF GEORGETOWN...

  20. 2012 NOAA Ortho-rectified Color Mosaic of Bremerton and Manchester, Washington

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — This data set contains ortho-rectified mosaic tiles, created as a product from the NOAA Integrated Ocean and Coastal Mapping (IOCM) initiative. The source imagery...

  1. Calibration of silicone rubber rods as passive samplers for pesticides at two different flow velocities: Modeling of sampling rates under water boundary layer and polymer control.

    Science.gov (United States)

    Martin, Alexis; Margoum, Christelle; Jolivet, Antoine; Assoumani, Azziz; El Moujahid, Bachir; Randon, Jérôme; Coquery, Marina

    2018-04-01

    There is a need to determine time-weighted average concentrations of polar contaminants such as pesticides by passive sampling in environmental waters. Calibration data for silicone rubber-based passive samplers are lacking for this class of compounds. The calibration data, sampling rate (R s ), and partition coefficient between silicone rubber and water (K sw ) were precisely determined for 23 pesticides and 13 candidate performance reference compounds (PRCs) in a laboratory calibration system over 14 d for 2 water flow velocities, 5 and 20 cm s -1 . The results showed that an in situ exposure duration of 7 d left a silicone rubber rod passive sampler configuration in the linear or curvilinear uptake period for 19 of the pesticides studied. A change in the transport mechanism from polymer control to water boundary layer control was observed for pesticides with a log K sw of approximately 3.3. The PRC candidates were not fully relevant to correct the impact of water flow velocity on R s . We therefore propose an alternative method based on an overall resistance to mass transfer model to adjust R s from laboratory experiments to in situ hydrodynamic conditions. We estimated diffusion coefficients (D s ) and thickness of water boundary layer (δ w ) as adjustable model parameters. Log D s values ranged from -12.13 to -10.07 m 2  s -1 . The estimated δ w value showed a power function correlation with water flow velocity. Environ Toxicol Chem 2018;37:1208-1218. © 2017 SETAC. © 2017 SETAC.

  2. A Single MO-CFTA Based Electronically/Temperature Insensitive Current-mode Half-wave and Full-wave Rectifiers

    OpenAIRE

    Weerapon Kongnun; Phamorn Silapan

    2013-01-01

    The article presents a current-mode full-wave rectifier employing multiple output current follower transconductance amplifier (MO-CFTA). The both circuits description is very simple, it merely comprises only single MO-CFTA, without external passive element. In addition, the magnitude and direction of output currents can be controlled via electronically method. Furthermore, the outputs are independent of the thermal voltage (VT). The performances of the proposed circuits are investigated thro...

  3. Design and test of a 2.25-MW transformer rectifier assembly

    Science.gov (United States)

    Cormier, R.; Daeges, J.

    1989-01-01

    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.

  4. Wideband Small-Signal Input dq Admittance Modeling of Six-Pulse Diode Rectifiers

    DEFF Research Database (Denmark)

    Yue, Xiaolong; Wang, Xiongfei; Blaabjerg, Frede

    2018-01-01

    This paper studies the wideband small-signal input dq admittance of six-pulse diode rectifiers. Considering the frequency coupling introduced by ripple frequency harmonics of d-and q-channel switching function, the proposed model successfully predicts the small-signal input dq admittance of six......-pulse diode rectifiers in high frequency regions that existing models fail to explain. Simulation and experimental results verify the accuracy of the proposed model....

  5. Superhigh-frequency circuit for the EPR spectrometer with rectifier screening

    International Nuclear Information System (INIS)

    Zhizhchenko, G.A.; Tsvirko, L.V.

    1983-01-01

    The hamodyne SHF circuit of a 3-cm EPR spectrometer with a reflecting resonator is described. The optimum operating mode of SHF-rectifier at a constant phase difference is automatically assured in the circuit. The circuit employs a reflecting p-i-n- attenuator and a SHF-rectifier sereen which simplify the spectrometer tuming. The circuit is used in a miniature EPR radiospectrometer Minsk EPR-6-type

  6. Changes in Inward Rectifier K+ Channels in Hepatic Stellate Cells During Primary Culture

    Science.gov (United States)

    Lee, Dong Hyeon; Kong, In Deok; Lee, Joong-Woo

    2008-01-01

    Purpose This study examined the expression and function of inward rectifier K+ channels in cultured rat hepatic stellate cells (HSC). Materials and Methods The expression of inward rectifier K+ channels was measured using real-time RT-PCR, and electrophysiological properties were determined using the gramicidin-perforated patch-clamp technique. Results The dominant inward rectifier K+ channel subtypes were Kir2.1 and Kir6.1. These dominant K+ channel subtypes decreased significantly during the primary culture throughout activation process. HSC can be classified into two subgroups: one with an inward-rectifying K+ current (type 1) and the other without (type 2). The inward current was blocked by Ba2+ (100 µM) and enhanced by high K+ (140 mM), more prominently in type 1 HSC. There was a correlation between the amplitude of the Ba2+-sensitive current and the membrane potential. In addition, Ba2+ (300 µM) depolarized the membrane potential. After the culture period, the amplitude of the inward current decreased and the membrane potential became depolarized. Conclusion HSC express inward rectifier K+ channels, which physiologically regulate membrane potential and decrease during the activation process. These results will potentially help determine properties of the inward rectifier K+ channels in HSC as well as their roles in the activation process. PMID:18581597

  7. New analysis and design of a RF rectifier for RFID and implantable devices.

    Science.gov (United States)

    Liu, Dong-Sheng; Li, Feng-Bo; Zou, Xue-Cheng; Liu, Yao; Hui, Xue-Mei; Tao, Xiong-Fei

    2011-01-01

    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-μm 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.

  8. The Development of High-Density Vertical Silicon Nanowires and Their Application in a Heterojunction Diode

    Directory of Open Access Journals (Sweden)

    Wen-Chung Chang

    2016-06-01

    Full Text Available Vertically aligned p-type silicon nanowire (SiNW arrays were fabricated through metal-assisted chemical etching (MACE of Si wafers. An indium tin oxide/indium zinc oxide/silicon nanowire (ITO/IZO/SiNW heterojunction diode was formed by depositing ITO and IZO thin films on the vertically aligned SiNW arrays. The structural and electrical properties of the resulting ITO/IZO/SiNW heterojunction diode were characterized by field emission scanning electron microscopy (FE-SEM, X-ray diffraction (XRD, and current−voltage (I−V measurements. Nonlinear and rectifying I−V properties confirmed that a heterojunction diode was successfully formed in the ITO/IZO/SiNW structure. The diode had a well-defined rectifying behavior, with a rectification ratio of 550.7 at 3 V and a turn-on voltage of 2.53 V under dark conditions.

  9. Production of electronic grade lunar silicon by disproportionation of silicon difluoride

    Science.gov (United States)

    Agosto, William N.

    1993-01-01

    Waldron has proposed to extract lunar silicon by sodium reduction of sodium fluorosilicate derived from reacting sodium fluoride with lunar silicon tetrafluoride. Silicon tetrafluoride is obtained by the action of hydrofluoric acid on lunar silicates. While these reactions are well understood, the resulting lunar silicon is not likely to meet electronic specifications of 5 nines purity. Dale and Margrave have shown that silicon difluoride can be obtained by the action of silicon tetrafluoride on elemental silicon at elevated temperatures (1100-1200 C) and low pressures (1-2 torr). The resulting silicon difluoride will then spontaneously disproportionate into hyperpure silicon and silicon tetrafluoride in vacuum at approximately 400 C. On its own merits, silicon difluoride polymerizes into a tough waxy solid in the temperature range from liquid nitrogen to about 100 C. It is the silicon analog of teflon. Silicon difluoride ignites in moist air but is stable under lunar surface conditions and may prove to be a valuable industrial material that is largely lunar derived for lunar surface applications. The most effective driver for lunar industrialization may be the prospects for industrial space solar power systems in orbit or on the moon that are built with lunar materials. Such systems would require large quantities of electronic grade silicon or compound semiconductors for photovoltaics and electronic controls. Since silicon is the most abundant semimetal in the silicate portion of any solar system rock (approximately 20 wt percent), lunar silicon production is bound to be an important process in such a solar power project. The lunar silicon extraction process is discussed.

  10. Lithographic wavelength control of an external cavity laser with a silicon photonic crystal cavity-based resonant reflector.

    Science.gov (United States)

    Liles, Alexandros A; Debnath, Kapil; O'Faolain, Liam

    2016-03-01

    We report the experimental demonstration of a new design for external cavity hybrid lasers consisting of a III-V semiconductor optical amplifier (SOA) with fiber reflector and a photonic crystal (PhC)-based resonant reflector on SOI. The silicon reflector is composed of an SU8 polymer bus waveguide vertically coupled to a PhC cavity and provides a wavelength-selective optical feedback to the laser cavity. This device exhibits milliwatt-level output power and side-mode suppression ratios of more than 25 dB.

  11. Long-pore Electrostatics in Inward-rectifier Potassium Channels

    Science.gov (United States)

    Robertson, Janice L.; Palmer, Lawrence G.; Roux, Benoît

    2008-01-01

    Inward-rectifier potassium (Kir) channels differ from the canonical K+ channel structure in that they possess a long extended pore (∼85 Å) for ion conduction that reaches deeply into the cytoplasm. This unique structural feature is presumably involved in regulating functional properties specific to Kir channels, such as conductance, rectification block, and ligand-dependent gating. To elucidate the underpinnings of these functional roles, we examine the electrostatics of an ion along this extended pore. Homology models are constructed based on the open-state model of KirBac1.1 for four mammalian Kir channels: Kir1.1/ROMK, Kir2.1/IRK, Kir3.1/GIRK, and Kir6.2/KATP. By solving the Poisson-Boltzmann equation, the electrostatic free energy of a K+ ion is determined along each pore, revealing that mammalian Kir channels provide a favorable environment for cations and suggesting the existence of high-density regions in the cytoplasmic domain and cavity. The contribution from the reaction field (the self-energy arising from the dielectric polarization induced by the ion's charge in the complex geometry of the pore) is unfavorable inside the long pore. However, this is well compensated by the electrostatic interaction with the static field arising from the protein charges and shielded by the dielectric surrounding. Decomposition of the static field provides a list of residues that display remarkable correspondence with existing mutagenesis data identifying amino acids that affect conduction and rectification. Many of these residues demonstrate interactions with the ion over long distances, up to 40 Å, suggesting that mutations potentially affect ion or blocker energetics over the entire pore. These results provide a foundation for understanding ion interactions in Kir channels and extend to the study of ion permeation, block, and gating in long, cation-specific pores. PMID:19001143

  12. Rectified factor networks for biclustering of omics data.

    Science.gov (United States)

    Clevert, Djork-Arné; Unterthiner, Thomas; Povysil, Gundula; Hochreiter, Sepp

    2017-07-15

    Biclustering has become a major tool for analyzing large datasets given as matrix of samples times features and has been successfully applied in life sciences and e-commerce for drug design and recommender systems, respectively. actor nalysis for cluster cquisition (FABIA), one of the most successful biclustering methods, is a generative model that represents each bicluster by two sparse membership vectors: one for the samples and one for the features. However, FABIA is restricted to about 20 code units because of the high computational complexity of computing the posterior. Furthermore, code units are sometimes insufficiently decorrelated and sample membership is difficult to determine. We propose to use the recently introduced unsupervised Deep Learning approach Rectified Factor Networks (RFNs) to overcome the drawbacks of existing biclustering methods. RFNs efficiently construct very sparse, non-linear, high-dimensional representations of the input via their posterior means. RFN learning is a generalized alternating minimization algorithm based on the posterior regularization method which enforces non-negative and normalized posterior means. Each code unit represents a bicluster, where samples for which the code unit is active belong to the bicluster and features that have activating weights to the code unit belong to the bicluster. On 400 benchmark datasets and on three gene expression datasets with known clusters, RFN outperformed 13 other biclustering methods including FABIA. On data of the 1000 Genomes Project, RFN could identify DNA segments which indicate, that interbreeding with other hominins starting already before ancestors of modern humans left Africa. https://github.com/bioinf-jku/librfn. djork-arne.clevert@bayer.com or hochreit@bioinf.jku.at. © The Author 2017. Published by Oxford University Press. All rights reserved. For permissions, please e-mail: journals.permissions@oup.com

  13. Polycrystalline Silicon Gettered by Porous Silicon and Heavy Phosphorous Diffusion

    Institute of Scientific and Technical Information of China (English)

    LIU Zuming(刘祖明); Souleymane K Traore; ZHANG Zhongwen(张忠文); LUO Yi(罗毅)

    2004-01-01

    The biggest barrier for photovoltaic (PV) utilization is its high cost, so the key for scale PV utilization is to further decrease the cost of solar cells. One way to improve the efficiency, and therefore lower the cost, is to increase the minority carrier lifetime by controlling the material defects. The main defects in grain boundaries of polycrystalline silicon gettered by porous silicon and heavy phosphorous diffusion have been studied. The porous silicon was formed on the two surfaces of wafers by chemical etching. Phosphorous was then diffused into the wafers at high temperature (900℃). After the porous silicon and diffusion layers were removed, the minority carrier lifetime was measured by photo-conductor decay. The results show that the lifetime's minority carriers are increased greatly after such treatment.

  14. Controlling the reproducibility of Coulomb blockade phenomena for gold nanoparticles on an organic monolayer/silicon system.

    Science.gov (United States)

    Caillard, L; Sattayaporn, S; Lamic-Humblot, A-F; Casale, S; Campbell, P; Chabal, Y J; Pluchery, O

    2015-02-13

    Two types of highly ordered organic layers were prepared on silicon modified with an amine termination for binding gold nanoparticles (AuNPs). These two grafted organic monolayers (GOMs), consisting of alkyl chains with seven or 11 carbon atoms, were grafted on oxide-free Si(111) surfaces as tunnel barriers between the silicon electrode and the AuNPs. Three kinds of colloidal AuNPs were prepared by reducing HAuCl4 with three different reactants: citrate (Turkevich synthesis, diameter ∼16 nm), ascorbic acid (diameter ∼9 nm), or NaBH4 (Natan synthesis, diameter ∼7 nm). Scanning tunnel spectroscopy (STS) was performed in a UHV STM at 40 K, and Coulomb blockade behaviour was observed. The reproducibility of the Coulomb behavior was analysed as a function of several chemical and physical parameters: size, crystallinity of the AuNPs, influence of surrounding surfactant molecules, and quality of the GOM/Si interface (degree of oxidation after the full processing). Samples were characterized with scanning tunneling microscope, STS, atomic force microscope, Fourier transform infrared spectroscopy, x-ray photoelectron spectroscopy (XPS), and high resolution transmission electronic microscope. We show that the reproducibility in observing Coulomb behavior can be as high as ∼80% with the Natan synthesis of AuNPs and GOMs with short alkyl chains.

  15. Diffusion-controlled growth of hydrogen pores in aluminum-silicon castings: In situ observation and modeling

    Energy Technology Data Exchange (ETDEWEB)

    Atwood, R.C.; Sridhar, S.; Zhang, W.; Lee, P.D.

    2000-01-24

    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.

  16. Failure rates for accelerated acceptance testing of silicon transistors

    Science.gov (United States)

    Toye, C. R.

    1968-01-01

    Extrapolation tables for the control of silicon transistor product reliability have been compiled. The tables are based on a version of the Arrhenius statistical relation and are intended to be used for low- and medium-power silicon transistors.

  17. Length dependence of rectification in organic co-oligomer spin rectifiers

    International Nuclear Information System (INIS)

    Hu Gui-Chao; Zhang Zhao; Li Ying; Ren Jun-Feng; Wang Chuan-Kui

    2016-01-01

    The rectification ratio of organic magnetic co-oligomer diodes is investigated theoretically by changing the molecular length. The results reveal two distinct length dependences of the rectification ratio: for a short molecular diode, the charge-current rectification changes little with the increase of molecular length, while the spin-current rectification is weakened sharply by the length; for a long molecular diode, both the charge-current and spin-current rectification ratios increase quickly with the length. The two kinds of dependence switch at a specific length accompanied with an inversion of the rectifying direction. The molecular ortibals and spin-resolved transmission analysis indicate that the dominant mechanism of rectification suffers a change at this specific length, that is, from asymmetric shift of molecular eigenlevels to asymmetric spatial localization of wave functions upon the reversal of bias. This work demonstrates a feasible way to control the rectification in organic co-oligomer spin diodes by adjusting the molecular length. (paper)

  18. Geochemistry of silicon isotopes

    Energy Technology Data Exchange (ETDEWEB)

    Ding, Tiping; Li, Yanhe; Gao, Jianfei; Hu, Bin [Chinese Academy of Geological Science, Beijing (China). Inst. of Mineral Resources; Jiang, Shaoyong [China Univ. of Geosciences, Wuhan (China).

    2018-04-01

    Silicon is one of the most abundant elements in the Earth and silicon isotope geochemistry is important in identifying the silicon source for various geological bodies and in studying the behavior of silicon in different geological processes. This book starts with an introduction on the development of silicon isotope geochemistry. Various analytical methods are described and compared with each other in detail. The mechanisms of silicon isotope fractionation are discussed, and silicon isotope distributions in various extraterrestrial and terrestrial reservoirs are updated. Besides, the applications of silicon isotopes in several important fields are presented.

  19. Economic modelling of energy services: Rectifying misspecified energy demand functions

    International Nuclear Information System (INIS)

    Hunt, Lester C.; Ryan, David L.

    2015-01-01

    Although it is well known that energy demand is derived, since energy is required not for its own sake but for the energy services it produces – such as heating, lighting, and motive power – energy demand models, both theoretical and empirical, often fail to take account of this feature. In this paper, we highlight the misspecification that results from ignoring this aspect, and its empirical implications – biased estimates of price elasticities and other measures – and provide a relatively simple and empirically practicable way to rectify it, which has a strong theoretical grounding. To do so, we develop an explicit model of consumer behaviour in which utility derives from consumption of energy services rather than from the energy sources that are used to produce them. As we discuss, this approach opens up the possibility of examining many aspects of energy demand in a theoretically sound way that have not previously been considered on a widespread basis, although some existing empirical work could be interpreted as being consistent with this type of specification. While this formulation yields demand equations for energy services rather than for energy or particular energy sources, these are shown to be readily converted, without added complexity, into the standard type of energy demand equation(s) that is (are) typically estimated. The additional terms that the resulting energy demand equations include, compared to those that are typically estimated, highlight the misspecification that is implicit when typical energy demand equations are estimated. A simple solution for dealing with an apparent drawback of this formulation for empirical purposes, namely that information is required on typically unobserved energy efficiency, indicates how energy efficiency can be captured in the model, such as by including exogenous trends and/or including its possible dependence on past energy prices. The approach is illustrated using an empirical example that involves

  20. Front-end circuit for position sensitive silicon and vacuum tube photomultipliers with gain control and depth of interaction measurement

    International Nuclear Information System (INIS)

    Herrero, Vicente; Colom, Ricardo; Gadea, Rafael; Lerche, Christoph W.; Cerda, Joaquin; Sebastia, Angel; Benlloch, Jose M.

    2007-01-01

    Silicon Photomultipliers, though still under development for mass production, may be an alternative to traditional Vacuum Photomultipliers Tubes (VPMT). As a consequence, electronic front-ends initially designed for VPMT will need to be modified. In this simulation, an improved architecture is presented which is able to obtain impact position and depth of interaction of a gamma ray within a continuous scintillation crystal, using either kind of PM. A current sensitive preamplifier stage with individual gain adjustment interfaces the multi-anode PM outputs with a current division resistor network. The preamplifier stage allows to improve front-end processing delay and temporal resolution behavior as well as to increase impact position calculation resolution. Depth of interaction (DOI) is calculated from the width of the scintillation light distribution, which is related to the sum of voltages in resistor network input nodes. This operation is done by means of a high-speed current mode scheme

  1. Reconfigurable Resonant Regulating Rectifier With Primary Equalization for Extended Coupling- and Loading-Range in Bio-Implant Wireless Power Transfer.

    Science.gov (United States)

    Li, Xing; Meng, Xiaodong; Tsui, Chi-Ying; Ki, Wing-Hung

    2015-12-01

    Wireless power transfer using reconfigurable resonant regulating (R(3)) rectification suffers from limited range in accommodating varying coupling and loading conditions. A primary-assisted regulation principle is proposed to mitigate these limitations, of which the amplitude of the rectifier input voltage on the secondary side is regulated by accordingly adjusting the voltage amplitude Veq on the primary side. A novel current-sensing method and calibration scheme track Veq on the primary side. A ramp generator simultaneously provides three clock signals for different modules. Both the primary equalizer and the R(3) rectifier are implemented as custom integrated circuits fabricated in a 0.35 μm CMOS process, with the global control implemented in FPGA. Measurements show that with the primary equalizer, the workable coupling and loading ranges are extended by 250% at 120 mW load and 300% at 1.2 cm coil distance compared to the same system without the primary equalizer. A maximum rectifier efficiency of 92.5% and a total system efficiency of 62.4% are demonstrated.

  2. Efficiency Enhancement of Silicon Solar Cells by Porous Silicon Technology

    Directory of Open Access Journals (Sweden)

    Eugenijus SHATKOVSKIS

    2012-09-01

    Full Text Available Silicon solar cells produced by a usual technology in p-type, crystalline silicon wafer were investigated. The manufactured solar cells were of total thickness 450 mm, the junction depth was of 0.5 mm – 0.7 mm. Porous silicon technologies were adapted to enhance cell efficiency. The production of porous silicon layer was carried out in HF: ethanol = 1 : 2 volume ratio electrolytes, illuminating by 50 W halogen lamps at the time of processing. The etching current was computer-controlled in the limits of (6 ÷ 14 mA/cm2, etching time was set in the interval of (10 ÷ 20 s. The characteristics and performance of the solar cells samples was carried out illuminating by Xenon 5000 K lamp light. Current-voltage characteristic studies have shown that porous silicon structures produced affect the extent of dark and lighting parameters of the samples. Exactly it affects current-voltage characteristic and serial resistance of the cells. It has shown, the formation of porous silicon structure causes an increase in the electric power created of solar cell. Conversion efficiency increases also respectively to the initial efficiency of cell. Increase of solar cell maximum power in 15 or even more percent is found. The highest increase in power have been observed in the spectral range of Dl @ (450 ÷ 850 nm, where ~ 60 % of the A1.5 spectra solar energy is located. It has been demonstrated that porous silicon technology is effective tool to improve the silicon solar cells performance.DOI: http://dx.doi.org/10.5755/j01.ms.18.3.2428

  3. Design and implementation of a radiation hardened silicon on sapphire (SOS) embedded signal conditioning unit controller (SCUC) for the RAPID instrument on the Cluster satellites

    International Nuclear Information System (INIS)

    Ersland, L.

    1992-07-01

    The Cluster mission consistens of four spacecrafts equipped with instruments capable of making comprehensive measurements of plasma particles and electromagnetic fields. The RAPID (Research with Adaptive Particle Imaging Detectors) spectrometer is one of many instruments on board the Cluster satellites. It is designed for fast analysis of energetic electrons and ions with a complete coverage of the unit sphere in phase space. This thesis describes the development and testing of an embedded controller for the Spectroscopic Camera for Electrons, Neutral and Ion Compositions (SCENIC), which is a part of the RAPID instrument. The design is implemented in two different CMOS circuit technologies, namely Actel's Field Programmable Gate Arrays and GEC Plessey's CMOS Silicon On Sapphire (SOS) gate array. The prototypes of the SOS gate array have been verified and characterized. This includes measurements of DC and AC parameters under different conditions, including total dose of gamma irradiation. 42 refs., 92 figs., 44 tabs

  4. Gas-temperature control in VHF- PECVD process for high-rate (>5 nm/s) growth of microcrystalline silicon thin films

    Energy Technology Data Exchange (ETDEWEB)

    Sobajima, Yasushi; Higuchi, Takuya; Chantana, Jakapan; Toyama, Toshihiko; Sada, Chitose; Matsuda, Akihisa; Okamoto, Hiroaki [Graduate School of Engineering Science, Osaka University, Toyonaka City (Japan)

    2010-04-15

    Surface-heating phenomenon by the radiation from high density plasma during growth of microcrystalline silicon ({mu}c-Si:H) thin films at high rate (> 5 nm/sec) is one of the crucial issues to be solved for obtaining high quality intrinsic-layer material for solar cells. We have utilized an optical emission spectroscopy (OES) in the plasma to observe the time evolution of gas temperature during film growth as well as the film-growth rate under {mu}c-Si:H deposition conditions at high rate. Gas temperature has been successfully controlled by changing total flow rate of monosilane (SiH{sub 4})/hydrogen (H{sub 2}) gas mixture, leading to a drastic improvement of optoelectronic properties in the resulting {mu}c-Si:H. (copyright 2010 WILEY-VCH Verlag GmbH and Co. KGaA, Weinheim) (orig.)

  5. 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

    International Nuclear Information System (INIS)

    Jansen, H V; De Boer, M J; Unnikrishnan, S; Louwerse, M C; Elwenspoek, M C

    2009-01-01

    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 (O 2 ) or a fluorocarbon (FC) gas (C 4 F 8 or CHF 3 ). 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 CHF 3 and C 4 F 8 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 CHF 3 is roughly 30 times the flow of C 4 F 8 , 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 O 2 is FC-free but shows only tolerable anisotropic results at

  6. 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

    Science.gov (United States)

    Jansen, H V; de Boer, M J; Unnikrishnan, S; Louwerse, M C; Elwenspoek, M C

    2009-03-01

    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

  7. Silicon Micromachined Microlens Array for THz Antennas

    Science.gov (United States)

    Lee, Choonsup; Chattopadhyay, Goutam; Mehdi, IImran; Gill, John J.; Jung-Kubiak, Cecile D.; Llombart, Nuria

    2013-01-01

    5 5 silicon microlens array was developed using a silicon micromachining technique for a silicon-based THz antenna array. The feature of the silicon micromachining technique enables one to microfabricate an unlimited number of microlens arrays at one time with good uniformity on a silicon wafer. This technique will resolve one of the key issues in building a THz camera, which is to integrate antennas in a detector array. The conventional approach of building single-pixel receivers and stacking them to form a multi-pixel receiver is not suited at THz because a single-pixel receiver already has difficulty fitting into mass, volume, and power budgets, especially in space applications. In this proposed technique, one has controllability on both diameter and curvature of a silicon microlens. First of all, the diameter of microlens depends on how thick photoresist one could coat and pattern. So far, the diameter of a 6- mm photoresist microlens with 400 m in height has been successfully microfabricated. Based on current researchers experiences, a diameter larger than 1-cm photoresist microlens array would be feasible. In order to control the curvature of the microlens, the following process variables could be used: 1. Amount of photoresist: It determines the curvature of the photoresist microlens. Since the photoresist lens is transferred onto the silicon substrate, it will directly control the curvature of the silicon microlens. 2. Etching selectivity between photoresist and silicon: The photoresist microlens is formed by thermal reflow. In order to transfer the exact photoresist curvature onto silicon, there needs to be etching selectivity of 1:1 between silicon and photoresist. However, by varying the etching selectivity, one could control the curvature of the silicon microlens. The figure shows the microfabricated silicon microlens 5 x5 array. The diameter of the microlens located in the center is about 2.5 mm. The measured 3-D profile of the microlens surface has a

  8. Electrical behavior of free-standing porous silicon layers

    International Nuclear Information System (INIS)

    Bazrafkan, I.; Dariani, R.S.

    2009-01-01

    The electrical behavior of porous silicon (PS) layers has been investigated on one side of p-type silicon with various anodization currents and electrolytes. The two contact I-V characteristic is assigned by the metal/porous silicon rectifying interface, whereas, by using the van der Pauw technique, a nonlinear dependence of the current vs voltage was found. By using Dimethylformamide (DMF) in electrolyte, regular structures and columns were formed and porosity increased. Our results showed that by using DMF, surface resistivity of PS samples increased and became double for free-standing porous silicon (FPS). The reason could be due to increasing surface area and adsorbing some more gas molecules. Activation energy of PS samples was also increased from 0.31 to 0.34 eV and became 0.35 eV for FPS. The changes induced by storage are attributed to the oxidation process of the internal surface of free-standing porous silicon layers.

  9. Theoretical study on the rectifying performance of organoimido derivatives of hexamolybdates.

    Science.gov (United States)

    Wen, Shizheng; Yang, Guochun; Yan, Likai; Li, Haibin; Su, Zhongmin

    2013-02-25

    We design a new type of molecular diode, based on the organoimido derivatives of hexamolybdates, by exploring the rectifying performances using density functional theory combined with the non-equilibrium Green's function. Asymmetric current-voltage characteristics were obtained for the models with an unexpected large rectification ratio. The rectifying behavior can be understood by the asymmetrical shift of the transmission peak observed under different polarities. It is interesting to find that the preferred electron-transport direction in our studied system is different from that of the organic D-bridge-A system. The results show that the studied organic-inorganic hybrid systems have an intrinsically robust rectifying ratio, which should be taken into consideration in the design of the molecular diodes. Copyright © 2013 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

  10. Possibility designing half-wave and full-wave molecular rectifiers by using single benzene molecule

    Science.gov (United States)

    Abbas, Mohammed A.; Hanoon, Falah H.; Al-Badry, Lafy F.

    2018-02-01

    This work focused on possibility designing half-wave and full-wave molecular rectifiers by using single and two benzene rings, respectively. The benzene rings were threaded by a magnetic flux that changes over time. The quantum interference effect was considered as the basic idea in the rectification action, the para and meta configurations were investigated. All the calculations are performed by using steady-state theoretical model, which is based on the time-dependent Hamiltonian model. The electrical conductance and the electric current are considered as DC output signals of half-wave and full-wave molecular rectifiers. The finding in this work opens up the exciting potential to use these molecular rectifiers in molecular electronics.

  11. Electron transport in InAs/AlGaSb ballistic rectifiers

    International Nuclear Information System (INIS)

    Maemoto, Toshihiko; Koyama, Masatoshi; Furukawa, Masashi; Takahashi, Hiroshi; Sasa, Shigehiko; Inoue, Masataka

    2006-01-01

    Nonlinear transport properties of a ballistic rectifier fabricated from InAs/AlGaSb heterostructures are reported. The operation of the ballistic rectifier is based on the guidance of carriers by a square anti-dot structure. The structure was defined by electron beam lithography and wet chemical etching. The DC characteristics and magneto-transport properties of the ballistic rectifier have been measured at 77 K and 4.2 K. Rectification effects relying on the ballistic transport were observed. From the four-terminal resistance measured at low magnetic fields, we also observed magneto-resistance fluctuations corresponding to the electron trajectories and symmetry-breaking electron scattering, which are influenced by the magnetic field strength

  12. Competitive inhibition can linearize dose-response and generate a linear rectifier.

    Science.gov (United States)

    Savir, Yonatan; Tu, Benjamin P; Springer, Michael

    2015-09-23

    Many biological responses require a dynamic range that is larger than standard bi-molecular interactions allow, yet the also ability to remain off at low input. Here we mathematically show that an enzyme reaction system involving a combination of competitive inhibition, conservation of the total level of substrate and inhibitor, and positive feedback can behave like a linear rectifier-that is, a network motif with an input-output relationship that is linearly sensitive to substrate above a threshold but unresponsive below the threshold. We propose that the evolutionarily conserved yeast SAGA histone acetylation complex may possess the proper physiological response characteristics and molecular interactions needed to perform as a linear rectifier, and we suggest potential experiments to test this hypothesis. One implication of this work is that linear responses and linear rectifiers might be easier to evolve or synthetically construct than is currently appreciated.

  13. Silicon Nanocrystal Synthesis in Microplasma Reactor

    Science.gov (United States)

    Nozaki, Tomohiro; Sasaki, Kenji; Ogino, Tomohisa; Asahi, Daisuke; Okazaki, Ken

    Nanocrystalline silicon particles with grains smaller than 5 nm are widely recognized as a key material in optoelectronic devices, lithium battery electrodes, and bio-medical labels. Another important characteristic is that silicon is an environmentally safe material that is used in numerous silicon technologies. To date, several synthesis methods such as sputtering, laser ablation, and plasma-enhanced chemical vapor deposition (PECVD) based on low-pressure silane chemistry (SiH4) have been developed for precise control of size and density distributions of silicon nanocrystals. In this study, we explore the possibility of microplasma technologies for efficient production of mono-dispersed nanocrystalline silicon particles on a micrometer-scale, continuous-flow plasma reactor operated at atmospheric pressure. Mixtures of argon, hydrogen, and silicon tetrachloride were activated using a very-high-frequency (144 MHz) power source in a capillary glass tube with volume of less than 1 μl. Fundamental plasma parameters of the microplasma were characterized using optical emission spectroscopy, which respectively indicated electron density of 1015 cm-3, argon excitation temperature of 5000 K, and rotational temperature of 1500 K. Such high-density non-thermal reactive plasma can decompose silicon tetrachloride into atomic silicon to produce supersaturated silicon vapor, followed by gas-phase nucleation via three-body collision: particle synthesis in high-density plasma media is beneficial for promoting nucleation processes. In addition, further growth of silicon nuclei can be terminated in a short-residence-time reactor. Micro-Raman scattering spectra showed that as-deposited particles are mostly amorphous silicon with a small fraction of silicon nanocrystals. Transmission electron micrography confirmed individual 3-15 nm silicon nanocrystals. Although particles were not mono-dispersed, they were well separated and not coagulated.

  14. Synthesis of Silicon Nanocrystals in Microplasma Reactor

    Science.gov (United States)

    Nozaki, Tomohiro; Sasaki, Kenji; Ogino, Tomohisa; Asahi, Daisuke; Okazaki, Ken

    Nanocrystalline silicon particles with a grain size of at least less than 10 nm are widely recognized as one of the key materials in optoelectronic devices, electrodes of lithium battery, bio-medical labels. There is also important character that silicon is safe material to the environment and easily gets involved in existing silicon technologies. To date, several synthesis methods such as sputtering, laser ablation, and plasma enhanced chemical vapor deposition (PECVD) based on low-pressure silane chemistry (SiH4) have been developed for precise control of size and density distributions of silicon nanocrystals. We explore the possibility of microplasma technologies for the efficient production of mono-dispersed nanocrystalline silicon particles in a micrometer-scale, continuous-flow plasma reactor operated at atmospheric pressure. Mixtures of argon, hydrogen, and silicon tetrachloride were activated using very high frequency (VHF = 144 MHz) power source in a capillary glass tube with a volume of less than 1 μ-liter. Fundamental plasma parameters of VHF capacitively coupled microplasma were characterized by optical emission spectroscopy, showing electron density of approximately 1015 cm-3 and rotational temperature of 1500 K, respectively. Such high-density non-thermal reactive plasma has a capability of decomposing silicon tetrachloride into atomic silicon to produce supersaturated atomic silicon vapor, followed by gas phase nucleation via three-body collision. The particle synthesis in high-density plasma media is beneficial for promoting nucleation process. In addition, further growth of silicon nuclei was able to be favorably terminated in a short-residence time reactor. Micro Raman scattering spectrum showed that as-deposited particles were mostly amorphous silicon with small fraction of silicon nanocrystals. Transmission electron micrograph confirmed individual silicon nanocrystals of 3-15 nm size. Although those particles were not mono-dispersed, they were

  15. Damage Mechanisms and Controlled Crack Propagation in a Hot Pressed Silicon Nitride Ceramic. Ph.D. Thesis - Northwestern Univ., 1993

    Science.gov (United States)

    Calomino, Anthony Martin

    1994-01-01

    The subcritical growth of cracks from pre-existing flaws in ceramics can severely affect the structural reliability of a material. The ability to directly observe subcritical crack growth and rigorously analyze its influence on fracture behavior is important for an accurate assessment of material performance. A Mode I fracture specimen and loading method has been developed which permits the observation of stable, subcritical crack extension in monolithic and toughened ceramics. The test specimen and procedure has demonstrated its ability to generate and stably propagate sharp, through-thickness cracks in brittle high modulus materials. Crack growth for an aluminum oxide ceramic was observed to be continuously stable throughout testing. Conversely, the fracture behavior of a silicon nitride ceramic exhibited crack growth as a series of subcritical extensions which are interrupted by dynamic propagation. Dynamic initiation and arrest fracture resistance measurements for the silicon nitride averaged 67 and 48 J/sq m, respectively. The dynamic initiation event was observed to be sudden and explosive. Increments of subcritical crack growth contributed to a 40 percent increase in fracture resistance before dynamic initiation. Subcritical crack growth visibly marked the fracture surface with an increase in surface roughness. Increments of subcritical crack growth loosen ceramic material near the fracture surface and the fracture debris is easily removed by a replication technique. Fracture debris is viewed as evidence that both crack bridging and subsurface microcracking may be some of the mechanisms contributing to the increase in fracture resistance. A Statistical Fracture Mechanics model specifically developed to address subcritical crack growth and fracture reliability is used together with a damaged zone of material at the crack tip to model experimental results. A Monte Carlo simulation of the actual experiments was used to establish a set of modeling input

  16. Microrectenna: A Terahertz Antenna and Rectifier on a Chip

    Science.gov (United States)

    Siegel, Peter

    2007-01-01

    A microrectenna that would operate at a frequency of 2.5 THz has been designed and partially fabricated. The circuit is intended to be a prototype of an extremely compact device that could be used to convert radio-beamed power to DC to drive microdevices (see Figure 1). The microrectenna (see Figure 2) circuit consists of an antenna, a diode rectifier and a DC output port. The antenna consists of a twin slot array in a conducting ground plane (denoted the antenna ground plane) over an enclosed quarter-wavelength-thick resonant cavity (denoted the reflecting ground plane). The circuit also contains a planar high-frequency low-parasitic Schottky-barrier diode, a low-impedance microstrip transmission line, capacitors, and contact beam leads. The entire 3-D circuit is fabricated monolithically from a single GaAs wafer. The resonant cavity renders the slot radiation pattern unidirectional with a half-power beam width of about 65. A unique metal mesh on the rear of the wafer forms the backplate for the cavity but allows the GaAs to be wet etched from the rear surface of the twin slot antennas and ground plane. The beam leads protrude past the edge of the chip and are used both to mount the microrectenna and to make the DC electrical connection with external circuitry. The antenna ground plane and the components on top of it are formed on a 2- m thick GaAs membrane that is grown in the initial wafer MBE (molecular beam epitaxy) process. The side walls of the antenna cavity are not metal coated and, hence, would cause some loss of power; however, the relatively high permittivity (epsilon=13) of the GaAs keeps the cavity modes well confined, without the usual surface-wave losses associated with thick dielectric substrates. The Schottky-barrier diode has the usual submicron dimensions associated with THz operation and is formed in a mesa process above the antenna ground plane. The diode is connected at the midpoint of a microstrip transmission line, which is formed on 1- m

  17. Rectifier Design Challenges for RF Wireless Power Transfer and Energy Harvesting Systems

    Directory of Open Access Journals (Sweden)

    A. Collado

    2017-06-01

    Full Text Available The design of wireless power transfer (WPT and energy harvesting (EH solutions poses different challenges towards achieving maximum RF-DC conversion efficiency in these systems. This paper covers several selected challenges when developing WPT and electromagnetic EH solutions, such as the design of multiband and broadband rectifiers, the minimization of the effect that load and input power variations may have on the system performance and finally the most optimum power combining mechanisms that can be used when dealing with multi-element rectifiers.

  18. Mechanism of single atom switch on silicon

    DEFF Research Database (Denmark)

    Quaade, Ulrich; Stokbro, Kurt; Thirstrup, C.

    1998-01-01

    We demonstrate single atom switch on silicon which operates by displacement of a hydrogen atom on the silicon (100) surface at room temperature. We find two principal effects by which the switch is controlled: a pronounced maximum of the switching probability as function of sample bias...

  19. Effect of ethanol at clinically relevant concentrations on atrial inward rectifier potassium current sensitive to acetylcholine.

    Science.gov (United States)

    Bébarová, Markéta; Matejovič, Peter; Pásek, Michal; Hořáková, Zuzana; Hošek, Jan; Šimurdová, Milena; Šimurda, Jiří

    2016-10-01

    Alcohol intoxication tends to induce arrhythmias, most often the atrial fibrillation. To elucidate arrhythmogenic mechanisms related to alcohol consumption, the effect of ethanol on main components of the ionic membrane current is investigated step by step. Considering limited knowledge, we aimed to examine the effect of clinically relevant concentrations of ethanol (0.8-80 mM) on acetylcholine-sensitive inward rectifier potassium current I K(Ach). Experiments were performed by the whole-cell patch clamp technique at 23 ± 1 °C on isolated rat and guinea-pig atrial myocytes, and on expressed human Kir3.1/3.4 channels. Ethanol induced changes of I K(Ach) in the whole range of concentrations applied; the effect was not voltage dependent. The constitutively active component of I K(Ach) was significantly increased by ethanol with the maximum effect (an increase by ∼100 %) between 8 and 20 mM. The changes were comparable in rat and guinea-pig atrial myocytes and also in expressed human Kir3.1/3.4 channels (i.e., structural correlate of I K(Ach)). In the case of the acetylcholine-induced component of I K(Ach), a dual ethanol effect was apparent with a striking heterogeneity of changes in individual cells. The effect correlated with the current magnitude in control: the current was increased by eth-anol in the cells showing small current in control and vice versa. The average effect peaked at 20 mM ethanol (an increase of the current by ∼20 %). Observed changes of action potential duration agreed well with the voltage clamp data. Ethanol significantly affected both components of I K(Ach) even in concentrations corresponding to light alcohol consumption.

  20. Nicotine at clinically relevant concentrations affects atrial inward rectifier potassium current sensitive to acetylcholine.

    Science.gov (United States)

    Bébarová, Markéta; Matejovič, Peter; Švecová, Olga; Kula, Roman; Šimurdová, Milena; Šimurda, Jiří

    2017-05-01

    Nicotine abuse is associated with variety of diseases including arrhythmias, most often atrial fibrillation (AF). Altered inward rectifier potassium currents including acetylcholine-sensitive current I K(Ach) are known to be related to AF pathogenesis. Since relevant data are missing, we aimed to investigate I K(Ach) changes at clinically relevant concentrations of nicotine. Experiments were performed by the whole cell patch clamp technique at 23 ± 1 °C on isolated rat atrial myocytes. Nicotine was applied at following concentrations: 4, 40 and 400 nM; ethanol at 20 mM (∼0.09%). Nicotine at 40 and 400 nM significantly activated constitutively active component of I K(Ach) with the maximum effect at 40 nM (an increase by ∼100%); similar effect was observed at -110 and -50 mV. Changes at 4 nM nicotine were negligible on average. Coapplication of 40 nM nicotine and 20 mM ethanol (which is also known to activate this current) did not show cumulative effect. In the case of acetylcholine-induced component of I K(Ach) , a dual effect of nicotine and its correlation with the current magnitude in control were apparent: the current was increased by nicotine in the cells showing small current in control and vice versa. The effect of 40 and 400 nM nicotine on acetylcholine-induced component of I K(Ach) was significantly different at -110 and -50 mV. We conclude that nicotine at clinically relevant concentrations significantly increased constitutively active component of I K(Ach) and showed a dual effect on its acetylcholine-induced component, similarly as ethanol. Synchronous application of nicotine and ethanol did not cause additive effect.

  1. Photo-EMF Sensitivity of Porous Silicon Thin Layer–Crystalline Silicon Heterojunction to Ammonia Adsorption

    Directory of Open Access Journals (Sweden)

    Kae Dal Kwack

    2011-01-01

    Full Text Available A new method of using photo-electromotive force in detecting gas and controlling sensitivity is proposed. Photo-electromotive force on the heterojunction between porous silicon thin layer and crystalline silicon wafer depends on the concentration of ammonia in the measurement chamber. A porous silicon thin layer was formed by electrochemical etching on p-type silicon wafer. A gas and light transparent electrical contact was manufactured to this porous layer. Photo-EMF sensitivity corresponding to ammonia concentration in the range from 10 ppm to 1,000 ppm can be maximized by controlling the intensity of illumination light.

  2. Photo-EMF sensitivity of porous silicon thin layer-crystalline silicon heterojunction to ammonia adsorption.

    Science.gov (United States)

    Vashpanov, Yuriy; Jung, Jae Il; Kwack, Kae Dal

    2011-01-01

    A new method of using photo-electromotive force in detecting gas and controlling sensitivity is proposed. Photo-electromotive force on the heterojunction between porous silicon thin layer and crystalline silicon wafer depends on the concentration of ammonia in the measurement chamber. A porous silicon thin layer was formed by electrochemical etching on p-type silicon wafer. A gas and light transparent electrical contact was manufactured to this porous layer. Photo-EMF sensitivity corresponding to ammonia concentration in the range from 10 ppm to 1,000 ppm can be maximized by controlling the intensity of illumination light.

  3. Photo-EMF Sensitivity of Porous Silicon Thin Layer–Crystalline Silicon Heterojunction to Ammonia Adsorption

    Science.gov (United States)

    Vashpanov, Yuriy; Jung, Jae Il; Kwack, Kae Dal

    2011-01-01

    A new method of using photo-electromotive force in detecting gas and controlling sensitivity is proposed. Photo-electromotive force on the heterojunction between porous silicon thin layer and crystalline silicon wafer depends on the concentration of ammonia in the measurement chamber. A porous silicon thin layer was formed by electrochemical etching on p-type silicon wafer. A gas and light transparent electrical contact was manufactured to this porous layer. Photo-EMF sensitivity corresponding to ammonia concentration in the range from 10 ppm to 1,000 ppm can be maximized by controlling the intensity of illumination light. PMID:22319353

  4. Subcellular localization of the delayed rectifier K(+) channels KCNQ1 and ERG1 in the rat heart

    DEFF Research Database (Denmark)

    Rasmussen, Hanne Borger; Møller, Morten; Knaus, Hans-Günther

    2003-01-01

    In the heart, several K(+) channels are responsible for the repolarization of the cardiac action potential, including transient outward and delayed rectifier K(+) currents. In the present study, the cellular and subcellular localization of the two delayed rectifier K(+) channels, KCNQ1 and ether...

  5. The Approach for Optimization of Transmission over Power Links using the Thyristor-Controlled Series Compensation

    Directory of Open Access Journals (Sweden)

    Fatima Zohra GHERBI

    2008-07-01

    Full Text Available The energy transportation networks can be improved by multiplying or creating new lines. This is not always the case for various reasons. The series capacities controlled by SCRs (Silicon Controlled Rectifiers represent a good alternative to optimize the existing or the new electric links, because they allow the increase of the dynamic stability, the damping of the power oscillations, while balancing the loads between the parallel circuits. This paper presents a resolution method to the power distribution by inserting the TCSC transit controller in the network. The insertion of the TCSC devices has given satisfying results that are, an increase of the transmitted active power and reduction of active losses, an improvement of the angular stability and the voltage stability without decreasing the transportation capacity.

  6. Quantitative analysis of the Ca2+ -dependent regulation of delayed rectifier K+ current IKs in rabbit ventricular myocytes.

    Science.gov (United States)

    Bartos, Daniel C; Morotti, Stefano; Ginsburg, Kenneth S; Grandi, Eleonora; Bers, Donald M

    2017-04-01

    [Ca 2+ ] i enhanced rabbit ventricular slowly activating delayed rectifier K + current (I Ks ) by negatively shifting the voltage dependence of activation and slowing deactivation, similar to perfusion of isoproterenol. Rabbit ventricular rapidly activating delayed rectifier K + current (I Kr ) amplitude and voltage dependence were unaffected by high [Ca 2+ ] i . When measuring or simulating I Ks during an action potential, I Ks was not different during a physiological Ca 2+ transient or when [Ca 2+ ] i was buffered to 500 nm. The slowly activating delayed rectifier K + current (I Ks ) contributes to repolarization of the cardiac action potential (AP). Intracellular Ca 2+ ([Ca 2+ ] i ) and β-adrenergic receptor (β-AR) stimulation modulate I Ks amplitude and kinetics, but details of these important I Ks regulators and their interaction are limited. We assessed the [Ca 2+ ] i dependence of I Ks in steady-state conditions and with dynamically changing membrane potential and [Ca 2+ ] i during an AP. I Ks was recorded from freshly isolated rabbit ventricular myocytes using whole-cell patch clamp. With intracellular pipette solutions that controlled free [Ca 2+ ] i , we found that raising [Ca 2+ ] i from 100 to 600 nm produced similar increases in I Ks as did β-AR activation, and the effects appeared additive. Both β-AR activation and high [Ca 2+ ] i increased maximally activated tail I Ks , negatively shifted the voltage dependence of activation, and slowed deactivation kinetics. These data informed changes in our well-established mathematical model of the rabbit myocyte. In both AP-clamp experiments and simulations, I Ks recorded during a normal physiological Ca 2+ transient was similar to I Ks measured with [Ca 2+ ] i clamped at 500-600 nm. Thus, our study provides novel quantitative data as to how physiological [Ca 2+ ] i regulates I Ks amplitude and kinetics during the normal rabbit AP. Our results suggest that micromolar [Ca 2+ ] i , in the submembrane or

  7. Buried oxide layer in silicon

    Science.gov (United States)

    Sadana, Devendra Kumar; Holland, Orin Wayne

    2001-01-01

    A process for forming Silicon-On-Insulator is described incorporating the steps of ion implantation of oxygen into a silicon substrate at elevated temperature, ion implanting oxygen at a temperature below 200.degree. C. at a lower dose to form an amorphous silicon layer, and annealing steps to form a mixture of defective single crystal silicon and polycrystalline silicon or polycrystalline silicon alone and then silicon oxide from the amorphous silicon layer to form a continuous silicon oxide layer below the surface of the silicon substrate to provide an isolated superficial layer of silicon. The invention overcomes the problem of buried isolated islands of silicon oxide forming a discontinuous buried oxide layer.

  8. Comparative Evaluation of Three-Phase Isolated Matrix-Type PFC Rectifier Concepts for High Efficiency 380VDC Supplies of Future Telco and Data Centers

    DEFF Research Database (Denmark)

    Cortes, Patricio; Bortis, Dominik; Pittini, Riccardo

    2014-01-01

    rectifier and in many cases a mains transformer is used to provide galvanic isolation. In order to achieve a high efficiency in the DC voltage generation and to implement the required isolation, a single-stage concept, such as a matrix-type rectifier that enables PFC functionality and galvanic isolation...... in a single conversion, can be beneficial. In addition, due to the fact that with the matrix-type rectifier the galvanic isolation is performed with a high-frequency transformer, this results in a more compact rectifier system compared to conventional systems where the mains-frequency isolation transformer...... is located at the input of the PFC rectifier. In this paper, an overview of isolated matrix-type PFC rectifier topologies is given and a new converter circuit is proposed, analyzed and comparatively evaluated against another promising PFC rectifier concept, the phase-modular IMY-rectifier....

  9. Regulation of the instantaneous inward rectifier and the delayed outward rectifier potassium channels by Captopril and Angiotensin II via the Phosphoinositide-3 kinase pathway in volume-overload-induced hypertrophied cardiac myocytes.

    Science.gov (United States)

    Alvin, Zikiar V; Laurence, Graham G; Coleman, Bernell R; Zhao, Aiqiu; Hajj-Moussa, Majd; Haddad, Georges E

    2011-07-01

    Early development of cardiac hypertrophy may be beneficial but sustained hypertrophic activation leads to myocardial dysfunction. Regulation of the repolarizing currents can be modulated by the activation of humoral factors, such as angiotensin II (ANG II) through protein kinases. The aim of this work is to assess the regulation of IK and IK1 by ANG II through the PI3-K pathway in hypertrophied ventricular myocytes. Cardiac eccentric hypertrophy was induced through volume-overload in adult male rats by aorto-caval shunt (3 weeks). After one week half of the rats were given captopril (2 weeks; 0.5 g/l/day) and the other half served as control. The voltage-clamp and western blot techniques were used to measure the delayed outward rectifier potassium current (IK) and the instantaneous inward rectifier potassium current (IK1) and Akt activity, respectively. Hypertrophied cardiomyocytes showed reduction in IK and IK1. Treatment with captopril alleviated this difference seen between sham and shunt cardiomyocytes. Acute administration of ANG II (10-6M) to cardiocytes treated with captopril reduced IK and IK1 in shunts, but not in sham. Captopril treatment reversed ANG II effects on IK and IK1 in a PI3-K-independent manner. However in the absence of angiotensin converting enzyme inhibition, ANG II increased both IK and IK1 in a PI3-K-dependent manner in hypertrophied cardiomyocytes. Thus, captopril treatment reveals a negative effect of ANG II on IK and IK1, which is PI3-K independent, whereas in the absence of angiotensin converting enzyme inhibition IK and IK1 regulation is dependent upon PI3-K.

  10. Effect of lycium barbarum polysaccharides on high glucose-induced retinal ganglion cell apoptosis, gene expression and delayed rectifier potassium current

    Directory of Open Access Journals (Sweden)

    Xiao-Fei Ma

    2017-05-01

    Full Text Available Objective: To study the effect of lycium barbarum polysaccharides (LBP on high glucoseinduced retinal ganglion cell apoptosis, gene expression and delayed rectifier potassium current. Methods: RGC-5 retinal ganglion cell lines were cultured and divided into control group, high glucose group and LBP group that were treated with normal DMEM, highglucose DMEM as well as high-glucose DMEM containing 500 ng/mL LBP respectively. After treatment, the Annexin V-FITC/PI kits were used to measure the number of apoptotic cells, fluorescence quantitative PCR kits were used to determine the expression of apoptosis genes and antioxidant genes, and patch clamp was used to test delayed rectifier potassium current. Results: 12, 24, 36 and 48 h after intervention, the number of apoptotic cells of high glucose group was significantly higher than that of control group, and the number of apoptotic cells of LBP group was significantly lower than that of high glucose group (P<0.05; 24 and 48 h after intervention, c-fos, c-jun, caspase-3, caspase-9, Nrf-2, NQO1 and HO-1 mRNA expression as well as potassium current amplitude (IK and maximum conductance (Gmax of high glucose group were significantly higher than those of control group while half maximum activation voltage (V1/2 was significantly lower than that of control group (P<0.05; c-fos, c-jun, caspase-3 and caspase-9 mRNA expression as well as IK and Gmax of LBP group were significantly lower than those of high glucose group, while Nrf-2, NQO1 and HO-1 mRNA expression as well as V1/2 of LBP group were significantly higher than those of high glucose group (P<0.05. Conclusions: LBP can reduce the high glucose-induced retinal ganglion cell apoptosis and inhibit the delayed rectifier potassium current amplitude.

  11. Modulation Doping of Silicon using Aluminium-induced Acceptor States in Silicon Dioxide

    OpenAIRE

    K?nig, Dirk; Hiller, Daniel; Gutsch, Sebastian; Zacharias, Margit; Smith, Sean

    2017-01-01

    All electronic, optoelectronic or photovoltaic applications of silicon depend on controlling majority charge carriers via doping with impurity atoms. Nanoscale silicon is omnipresent in fundamental research (quantum dots, nanowires) but also approached in future technology nodes of the microelectronics industry. In general, silicon nanovolumes, irrespective of their intended purpose, suffer from effects that impede conventional doping due to fundamental physical principles such as out-diffusi...

  12. Power converter for raindrop energy harvesting application: Half-wave rectifier

    Science.gov (United States)

    Izrin, Izhab Muhammad; Dahari, Zuraini

    2017-10-01

    Harvesting raindrop energy by capturing vibration from impact of raindrop have been explored extensively. Basically, raindrop energy is generated by converting the kinetic energy of raindrop into electrical energy by using polyvinylidene fluoride (PVDF) piezoelectric. In this paper, a power converter using half-wave rectifier for raindrop harvesting energy application is designed and proposed to convert damping alternating current (AC) generated by PVDF into direct current (DC). This research presents parameter analysis of raindrop simulation used in the experiment and resistive load effect on half-wave rectifier converter. The experiment is conducted by using artificial raindrop from the height of 1.3 m to simulate the effect of different resistive load on the output of half-wave rectifier converter. The results of the 0.68 MΩ resistive load showed the best performance of the half-wave rectifier converter used in raindrop harvesting energy system, which generated 3.18 Vaverage. The peak instantaneous output generated from this experiment is 15.36 µW.

  13. Rectifying effect of heterojunctions between metals and doped conducting polymer nanostructure pellets

    International Nuclear Information System (INIS)

    Long Yunze; Yin Zhihua; Hui Wen; Chen Zhaojia; Wan Meixiang

    2008-01-01

    This paper reports that the Schottky junctions between low work function metals (e.g. Al and In) and doped semiconducting polymer pellets (e.g. polyaniline (PANI) microsphere pellet and polypyrrole (PPy) nanotube pellet) have been prepared and studied. Since Ag is a high work function metal which can make an ohmic contact with polymer, silver paste was used to fabricate the electrodes. The Al/PANI/Ag heterojunction shows an obvious rectifying effect as shown in I – V characteristic curves (rectifying ratio γ = 5 at ±6 V bias at room temperature). As compared to the Al/PANI/Ag, the heterojunction between In and PANI (In/PANI/Ag) exhibits a lower rectifying ratio γ = 1.6 at ±2 V bias at room temperature. In addition, rectifying effect was also observed in the heterojunctions Al/PPy/Ag (γ = 3.2 at ±1.6 V bias) and In/PPy/Ag (γ = 1.2 at ±3.0 V bias). The results were discussed in terms of thermoionic emission theory. (condensed matter: electronic structure, electrical, magnetic, and optical properties)

  14. Connection of OWPPs to HVDC networks using VSCs and Diode Rectifiers: an Overview

    DEFF Research Database (Denmark)

    Saborío-Romano, Oscar; Bidadfar, Ali; Göksu, Ömer

    This paper provides an overview of two technologies for connecting offshore wind power plants (offshore WPPs, OWPPs) to high-voltage direct current (HVDC) networks: voltage source converters (VSCs) and diode rectifiers (DRs). Current grid code requirements for the connection of such power plants...

  15. Self-Biased Differential Rectifier with Enhanced Dynamic Range for Wireless Powering

    KAUST Repository

    Ouda, Mahmoud H.; Khalil, Waleed; Salama, Khaled N.

    2016-01-01

    A self-biased, cross-coupled, differential rectifier is proposed with enhanced power-conversion efficiency over an extended range of input power. A prototype is designed for UHF 433MHz RF power-harvesting applications and is implemented using 0.18μm

  16. 28.3THz bowtie antenna integrated rectifier for infrared energy harvesting

    KAUST Repository

    Gadalla, Mena N.; Shamim, Atif

    2014-01-01

    The design, fabrication and characterization of an asymmetric 28.3 THz antenna integrated rectifier (rectenna) using Au/Al2O3/Pt is presented. The rectenna design comprises a sharp tip bowtie antenna and a tunneling Metal-insulator-Metal (MIM) diode

  17. Effect of ethanol at clinically relevant concentrations on atrial inward rectifier potassium current sensitive to acetylcholine

    Czech Academy of Sciences Publication Activity Database

    Bébarová, M.; Matejovič, P.; Pásek, Michal; Hořáková, Z.; Hošek, J.; Šimurdová, M.; Šimurda, J.

    2016-01-01

    Roč. 389, č. 10 (2016), s. 1049-1058 ISSN 0028-1298 Institutional support: RVO:61388998 Keywords : arrhythmias * atrial cardiomyocyte * inward rectifier potasssium current * ethanol * rat atrial cell model Subject RIV: BO - Biophysics Impact factor: 2.558, year: 2016

  18. Current Mode Full-Wave Rectifier Based on a Single MZC-CDTA

    Directory of Open Access Journals (Sweden)

    Neeta Pandey

    2013-01-01

    Full Text Available This paper presents a current mode full-wave rectifier based on single modified Z copy current difference transconductance amplifier (MZC-CDTA and two switches. The circuit is simple and is suitable for IC implementation. The functionality of the circuit is verified with SPICE simulation using 0.35 μm TSMC CMOS technology parameters.

  19. US Mains Stacked Very High Frequency Self-oscillating Resonant Power Converter with Unified Rectifier

    DEFF Research Database (Denmark)

    Pedersen, Jeppe Arnsdorf; Madsen, Mickey Pierre; Mønster, Jakob Døllner

    2016-01-01

    This paper describes a Very High Frequency (VHF) converter made with three Class-E inverters and a single ClassDE rectifier. The converter is designed for the US mains (120 V, 60 Hz) and can deliver 9 W to a 60 V LED. The converter has a switching frequency of 37 MHz and achieves an efficiency...

  20. Modeling removal of accumulated potassium from T-tubules by inward rectifier potassium channels

    NARCIS (Netherlands)

    Wallinga, W.; Vliek, M.; Wienk, E.D.; Alberink, M.J.; Ypey, D.L.; Ypey, D.L.

    1996-01-01

    The membrane models of Cannon et al. (1993) and Alberink et al. (1995) for mammalian skeletal muscle fibers are based upon Hodgkin-Huxley descriptions of sodium, potassium delayed rectifier and leak conductances and the capacitive current taking into account fast inactivation of sodium channels. Now

  1. Design of the LC+trap filter for a current source rectifier

    DEFF Research Database (Denmark)

    Min, Huang; Wang, Xiongfei; Loh, Poh Chiang

    2015-01-01

    This paper investigates an LC + trap filter for current source converters to improve the switching harmonic attenuation. The resonant frequency characteristics of the filter of current source rectifier are analyzed. A filter design procedure is proposed based on the input power factor, filter...

  2. Ac loss measurements on a superconducting transformer for a 25 kA superconducting rectifier

    NARCIS (Netherlands)

    ten Kate, Herman H.J.; Mulders, J.M.; de Reuver, J.L.; van de Klundert, L.J.M.

    1984-01-01

    Ac loss measurements have been performed on a superconducting transformer. The transformer is a part of a 25 kA thermally switched superconducting rectifier operating at a frequency of 0.1 Hz. The loss measurements have been automatized by means of a microcomputer sampling four relevant signals and

  3. Development of a thermally switched superconducting rectifier for 100 kA

    NARCIS (Netherlands)

    Mulder, G.B.J.; Mulder, G.B.J.; ten Kate, Herman H.J.; Krooshoop, Hendrikus J.G.; van de Klundert, L.J.M.; van de Klundert, L.J.M.

    1991-01-01

    A full-wave superconducting rectifier for 100 kA has been developed. Typical design values of this device are: a secondary current of 100 kA, a primary amplitude of 20 A, an operating frequency of 0.5 Hz, and an average power on the order of 100 W. The rectification is achieved by means of thermally

  4. Development of a 50-60 Hz thermally switched superconducting rectifier

    NARCIS (Netherlands)

    Chevtchenko, O.A.; ten Kate, Herman H.J.; Krooshoop, Hendrikus J.G.; Markovsky, N.V.; Mulder, G.B.J.; Mulder, G.B.J.

    1993-01-01

    A full-wave thermally switched superconducting rectifier, able to operate directly from the mains at the 50-60-Hz frequency, has been developed. Typical design output values of this device are a current of 300 A, a voltage of up to 1 V, an average power of up to 100 VA, and an efficiency better than

  5. A high-efficiency low-voltage CMOS rectifier for harvesting energy in implantable devices.

    Science.gov (United States)

    Hashemi, S Saeid; Sawan, Mohamad; Savaria, Yvon

    2012-08-01

    We present, in this paper, a new full-wave CMOS rectifier dedicated for wirelessly-powered low-voltage biomedical implants. It uses bootstrapped capacitors to reduce the effective threshold voltage of selected MOS switches. It achieves a significant increase in its overall power efficiency and low voltage-drop. Therefore, the rectifier is good for applications with low-voltage power supplies and large load current. The rectifier topology does not require complex circuit design. The highest voltages available in the circuit are used to drive the gates of selected transistors in order to reduce leakage current and to lower their channel on-resistance, while having high transconductance. The proposed rectifier was fabricated using the standard TSMC 0.18 μm CMOS process. When connected to a sinusoidal source of 3.3 V peak amplitude, it allows improving the overall power efficiency by 11% compared to the best recently published results given by a gate cross-coupled-based structure.

  6. Self-Oscillating Resonant Gate Drive for Resonant Inverters and Rectifiers Composed Solely of Passive Components

    DEFF Research Database (Denmark)

    Madsen, Mickey Pierre; Pedersen, Jeppe Arnsdorf; Knott, Arnold

    2014-01-01

    to improve the performance of the gate drive and how the gate drive can be implemented in a class E inverter, a class DE inverter and in class E inverter with a synchronous class E rectifier. The paper shows practical implementations of all the proposed inverters and converters operating in the Very High...

  7. Accumulation of slowly activating delayed rectifier potassium current (IKs) in canine ventricular myocytes

    DEFF Research Database (Denmark)

    Stengl, Milan; Volders, Paul G A; Thomsen, Morten Bækgaard

    2003-01-01

    In guinea-pig ventricular myocytes, in which the deactivation of slowly activating delayed rectifier potassium current (IKs) is slow, IKs can be increased by rapid pacing as a result of incomplete deactivation and subsequent current accumulation. Whether accumulation of IKs occurs in dogs, in which...

  8. Delayed rectifier potassium channels are involved in SO2 derivative-induced hippocampal neuronal injury.

    Science.gov (United States)

    Li, Guangke; Sang, Nan

    2009-01-01

    Recent studies implicate the possible neurotoxicity of SO(2), however, its mechanisms remain unclear. In the present study, we investigated SO(2) derivative-induced effect on delayed rectifier potassium channels (I(K)) and cellular death/apoptosis in primary cultured hippocampal neurons. The results demonstrate that SO(2) derivatives (NaHSO(3) and Na(2)SO(3), 3:1M/M) effectively augmented I(K) and promoted the activation of delayed rectifier potassium channels. Also, SO(2) derivatives increased neuronal death percentage and contributed to the formation of DNA ladder in concentration-dependent manners. Interestingly, the neuronal death and DNA ladder formation, caused by SO(2) derivatives, could be attenuated by the delayed rectifier potassium channel blocker (tetraethylammonium, TEA), but not by the transient outward potassium channel blocker (4-aminopyridine, 4-AP). It implies that stimulating delayed rectifier potassium channels were involved in SO(2) derivative-caused hippocampal neuronal insults, and blocking these channels might be one of the possibly clinical treatment for SO(2)-caused neuronal dysfunction.

  9. Energy Saving in Three-Phase Diode Rectifiers Using EI Technique with Adjustable Switching Frequency Scheme

    DEFF Research Database (Denmark)

    Davari, Pooya; Zare, Firuz; Yang, Yongheng

    2016-01-01

    A front-end rectifier can significantly impact a power electronics system performance and efficiency for applications such as motor drive where the system commonly operates under partial loading conditions. This paper proposes an adjustable switching frequency scheme using an electronic inductor...

  10. Crossbar memory array of organic bistable rectifying diodes for nonvolatile data storage

    NARCIS (Netherlands)

    Asadi, Kamal; Li, Mengyuan; Stingelin, Natalie; Blom, Paul W. M.; de Leeuw, Dago M.

    2010-01-01

    Cross-talk in memories using resistive switches in a cross-bar geometry can be prevented by integration of a rectifying diode. We present a functional cross bar memory array using a phase separated blend of a ferroelectric and a semiconducting polymer as storage medium. Each intersection acts

  11. Colloidal characterization of silicon nitride and silicon carbide

    Science.gov (United States)

    Feke, Donald L.

    1986-01-01

    The colloidal behavior of aqueous ceramic slips strongly affects the forming and sintering behavior and the ultimate mechanical strength of the final ceramic product. The colloidal behavior of these materials, which is dominated by electrical interactions between the particles, is complex due to the strong interaction of the solids with the processing fluids. A surface titration methodology, modified to account for this interaction, was developed and used to provide fundamental insights into the interfacial chemistry of these systems. Various powder pretreatment strategies were explored to differentiate between true surface chemistry and artifacts due to exposure history. The colloidal behavior of both silicon nitride and carbide is dominated by silanol groups on the powder surfaces. However, the colloid chemistry of silicon nitride is apparently influenced by an additional amine group. With the proper powder treatments, silicon nitride and carbide powder can be made to appear colloidally equivalent. The impact of these results on processing control will be discussed.

  12. Controlled growth of periodically aligned copper-silicide nanocrystal arrays on silicon directed by laser-induced periodic surface structures (LIPSS)

    Science.gov (United States)

    Nürnberger, Philipp; Reinhardt, Hendrik M.; Rhinow, Daniel; Riedel, René; Werner, Simon; Hampp, Norbert A.

    2017-10-01

    In this paper we introduce a versatile tool for the controlled growth and alignment of copper-silicide nanocrystals. The method takes advantage of a unique self-organization phenomenon denoted as laser-induced periodic surface structures (LIPSS). Copper films (3 ± 0.2 nm) are sputter-deposited onto single crystal silicon (100) substrates with a thin oxide layer (4 ± 0.2 nm), and subsequently exposed to linearly polarized nanosecond laser pulses (τ ≈ 6 ns) at a central wavelength of 532 nm. The irradiation triggers dewetting of the Cu film and simultaneous formation of periodic Cu nanowires (LIPSS), which partially penetrate the oxide layer to the Si substrate. These LIPSS act as nucleation centers for the growth of Cu-Si crystals during thermal processing at 500 °C under forming gas 95/5 atmosphere. Exemplified by our model system Cu/SiO2/Si, LIPSS are demonstrated to facilitate the diffusion reaction between Cu and underlying Si. Moreover, adjustment of the laser polarization allows us to precisely control the nanocrystal alignment with respect to the LIPSS orientation. Potential applications and conceivable alternatives of this process are discussed.

  13. Microfluidic assembly of monodisperse multistage pH-responsive polymer/porous silicon composites for precisely controlled multi-drug delivery.

    Science.gov (United States)

    Liu, Dongfei; Zhang, Hongbo; Herranz-Blanco, Bárbara; Mäkilä, Ermei; Lehto, Vesa-Pekka; Salonen, Jarno; Hirvonen, Jouni; Santos, Hélder A

    2014-05-28

    We report an advanced drug delivery platform for combination chemotherapy by concurrently incorporating two different drugs into microcompoistes with ratiometric control over the loading degree. Atorvastatin and celecoxib were selected as model drugs due to their different physicochemical properties and synergetic effect on colorectal cancer prevention and inhibition. To be effective in colorectal cancer prevention and inhibition, the produced microcomposite contained hypromellose acetate succinate, which is insoluble in acidic conditions but highly dissolving at neutral or alkaline pH conditions. Taking advantage of the large pore volume of porous silicon (PSi), atorvastatin was firstly loaded into the PSi matrix, and then encapsulated into the pH-responsive polymer microparticles containing celecoxib by microfluidics in order to obtain multi-drug loaded polymer/PSi microcomposites. The prepared microcomposites showed monodisperse size distribution, multistage pH-response, precise ratiometric controlled loading degree towards the simultaneously loaded drug molecules, and tailored release kinetics of the loaded cargos. This attractive microcomposite platform protects the payloads from being released at low pH-values, and enhances their release at higher pH-values, which can be further used for colon cancer prevention and treatment. Overall, the pH-responsive polymer/PSi-based microcomposite can be used as a universal platform for the delivery of different drug molecules for combination therapy. © 2014 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

  14. N-(2-methoxyphenyl) benzenesulfonamide, a novel regulator of neuronal G protein-gated inward rectifier K+ channels.

    Science.gov (United States)

    Walsh, Kenneth B; Gay, Elaine A; Blough, Bruce E; Geurkink, David W

    2017-11-15

    G protein-gated inward rectifier K + (GIRK) channels are members of the super-family of proteins known as inward rectifier K + (Kir) channels and are expressed throughout the peripheral and central nervous systems. Neuronal GIRK channels are the downstream targets of a number of neuromodulators including opioids, somatostatin, dopamine and cannabinoids. Previous studies have demonstrated that the ATP-sensitive K + channel, another member of the Kir channel family, is regulated by sulfonamide drugs. Therefore, to determine if sulfonamides also modulate GIRK channels, we screened a library of arylsulfonamide compounds using a GIRK channel fluorescent assay that utilized pituitary AtT20 cells expressing GIRK channels along with the somatostatin type-2 and -5 receptors. Enhancement of the GIRK channel fluorescent signal by one compound, N-(2-methoxyphenyl) benzenesulfonamide (MPBS), was dependent on the activation of the channel by somatostatin. In whole-cell patch clamp experiments, application of MPBS both shifted the somatostatin concentration-response curve (EC 50 = 3.5nM [control] vs.1.0nM [MPBS]) for GIRK channel activation and increased the maximum GIRK current measured with 100nM somatostatin. However, GIRK channel activation was not observed when MPBS was applied to the cells in the absence of somatostatin. While the MPBS structural analog 4-fluoro-N-(2-methoxyphenyl) benzenesulfonamide also augmented the somatostatin-induced GIRK fluorescent signal, no increase in the signal was observed with the sulfonamides tolbutamide, sulfapyridine and celecoxib. In conclusion, MPBS represents a novel prototypic GPCR-dependent regulator of neuronal GIRK channels. Copyright © 2017 Elsevier B.V. All rights reserved.

  15. Fixture and method for rectifying damaged guide thimble insert sleeves in a reconstitutable fuel assembly

    International Nuclear Information System (INIS)

    Shallenberger, J.M.; Ferlan, S.J.

    1987-01-01

    A guide thimble damage-rectifying method is described for use on a reconstitutable fuel assembly being held in a work station with its top nozzle removed to expose a plurality of guide thimbles having one of several different types of damage. The method consists of: (a) providing a base having a plurality of tool positioning openings defined therein in a pattern matched with that of the guide thimbles of the fuel assembly; (b) mounting the base on the work station with its tool positioning openings in alignment with the guide thimbles of the fuel assembly and such that the base is movable toward the guide thimbles; (c) providing a plurality of different tools each operable to rectify one of the different types of guide thimble damage; (d) mounting selected ones of the different tools in respective ones of the openings of the base in alignment with ones of the thimbles having the respective types of guide thimble damage capable of being rectified by the selected tools such that upon movement of the base toward the guide thimbles the respective types of guide thimble damage will be rectified by the selected tools; (e) providing a group of positioning elements; (f) mounting the positioning elements in selected ones of the base openings corresponding to undamaged ones of the guide thimbles such that upon movement of the base toward the guide thimbles the positioning elements become mounted on upper end portions of the corresponding undamaged ones of the guide thimbles for precisely locating the fixture relative to the guide thimble upper end portions for accurate performance of the repairable damage rectifying operation by the tools as the base is moved toward the guide thimbles; and (g) moving the base toward the guide thimbles so as to mount the positioning elements on the corresponding ones of the undamaged guide thimbles and effect rectification of the damaged guide thimbles by the selected tools

  16. Specific residues of the cytoplasmic domains of cardiac inward rectifier potassium channels are effective antifibrillatory targets

    Science.gov (United States)

    Noujaim, Sami F.; Stuckey, Jeanne A.; Ponce-Balbuena, Daniela; Ferrer-Villada, Tania; López-Izquierdo, Angelica; Pandit, Sandeep; Calvo, Conrado J.; Grzeda, Krzysztof R.; Berenfeld, Omer; Sánchez Chapula, José A.; Jalife, José

    2010-01-01

    Atrial and ventricular tachyarrhythmias can be perpetuated by up-regulation of inward rectifier potassium channels. Thus, it may be beneficial to block inward rectifier channels under conditions in which their function becomes arrhythmogenic (e.g., inherited gain-of-function mutation channelopathies, ischemia, and chronic and vagally mediated atrial fibrillation). We hypothesize that the antimalarial quinoline chloroquine exerts potent antiarrhythmic effects by interacting with the cytoplasmic domains of Kir2.1 (IK1), Kir3.1 (IKACh), or Kir6.2 (IKATP) and reducing inward rectifier potassium currents. In isolated hearts of three different mammalian species, intracoronary chloroquine perfusion reduced fibrillatory frequency (atrial or ventricular), and effectively terminated the arrhythmia with resumption of sinus rhythm. In patch-clamp experiments chloroquine blocked IK1, IKACh, and IKATP. Comparative molecular modeling and ligand docking of chloroquine in the intracellular domains of Kir2.1, Kir3.1, and Kir6.2 suggested that chloroquine blocks or reduces potassium flow by interacting with negatively charged amino acids facing the ion permeation vestibule of the channel in question. These results open a novel path toward discovering antiarrhythmic pharmacophores that target specific residues of the cytoplasmic domain of inward rectifier potassium channels.—Noujaim, S. F., Stuckey, J. A., Ponce-Balbuena, D., Ferrer-Villada, T., López-Izquierdo, A., Pandit, S., Calvo, C. J., Grzeda, K. R., Berenfeld, O., Sánchez Chapula, J. A., Jalife, J. Specific residues of the cytoplasmic domains of cardiac inward rectifier potassium channels are effective antifibrillatory targets. PMID:20585026

  17. Silicon-micromachined microchannel plates

    International Nuclear Information System (INIS)

    Beetz, Charles P.; Boerstler, Robert; Steinbeck, John; Lemieux, Bryan; Winn, David R.

    2000-01-01

    Microchannel plates (MCP) fabricated from standard silicon wafer substrates using a novel silicon micromachining process, together with standard silicon photolithographic process steps, are described. The resulting SiMCP microchannels have dimensions of ∼0.5 to ∼25 μm, with aspect ratios up to 300, and have the dimensional precision and absence of interstitial defects characteristic of photolithographic processing, compatible with positional matching to silicon electronics readouts. The open channel areal fraction and detection efficiency may exceed 90% on plates up to 300 mm in diameter. The resulting silicon substrates can be converted entirely to amorphous quartz (qMCP). The strip resistance and secondary emission are developed by controlled depositions of thin films, at temperatures up to 1200 deg. C, also compatible with high-temperature brazing, and can be essentially hydrogen, water and radionuclide-free. Novel secondary emitters and cesiated photocathodes can be high-temperature deposited or nucleated in the channels or the first strike surface. Results on resistivity, secondary emission and gain are presented

  18. Prevention and control of proliferative vitreoretinopathy: primary retinal detachment surgery using silicone oil as a planned two-stage procedure in high-risk cases.

    Science.gov (United States)

    Alexander, P; Prasad, R; Ang, A; Poulson, A V; Scott, J D; Snead, M P

    2008-06-01

    For rhegmatogenous retinal detachment, reattachment with a single procedure is associated with better visual outcomes. In the past, silicone oil has been used mostly as a last resort following failed primary surgery. This study evaluates a novel approach to patients at high risk of primary failure, using silicone tamponade as the primary stage of a planned two-stage procedure. We report a series of 140 eyes that underwent primary surgery for rhegmatogenous retinal detachment. Patients at higher risk of surgical failure (eg giant retinal tear, inability to posture, poor view, uncertainty of location of primary break, primary proliferative vitreoretinopathy (PVR), multiple tears with rolled posterior edges, retinoschisis/detachment, staphyloma with macular hole) were managed by a planned staged procedure using primary silicone oil tamponade. This was followed by silicone removal at a later date. Fifty-four eyes underwent scleral buckling alone, with primary success in 52/54 (96%). Fifty-three eyes underwent vitrectomy and gas, achieving primary success in 50/53 (94%). Thirty-three eyes were classified high risk and managed with primary silicone. Silicone was safely removed in 22/25. In eight eyes, silicone was retained without attempt at removal. In total, primary retinal reattachment was achieved in 128 of 140 eyes (91.4%). Of these, 124 (97%) did not require long-term tamponade. Only four eyes (2.9%) developed PVR. A planned two-stage approach to highrisk cases of retinal detachment using primary silicone oil tamponade followed by silicone removal can achieve a high primary reattachment rate with less than 3% incidence of PVR.

  19. Special power supply and control system for the gas-cooled fast reactor-core flow test loop

    International Nuclear Information System (INIS)

    Hudson, T.L.

    1981-09-01

    The test bundle in the Gas-Cooled Fast Reactor-Core Flow Test Loop (GCFR-CFTL) requires a source of electrical power that can be controlled accurately and reliably over a wide range of steady-state and transient power levels and skewed power distributions to simulate GCFR operating conditions. Both ac and dc power systems were studied, and only those employing silicon-controlled rectifiers (SCRs) could meet the requirements. This report summarizes the studies, tests, evaluations, and development work leading to the selection. it also presents the design, procurement, testing, and evaluation of the first 500-kVa LMPL supply. The results show that the LMPL can control 60-Hz sine wave power from 200 W to 500 kVA

  20. Silicon: electrochemistry and luminescence

    NARCIS (Netherlands)

    Kooij, Ernst Stefan

    1997-01-01

    The electrochemistry of crystalline and porous silicon and the luminescence from porous silicon has been studied. One chapter deals with a model for the anodic dissolution of silicon in HF solution. In following chapters both the electrochemistry and various ways of generating visible