Analysis of field-driven clocking for molecular quantum-dot cellular automata based circuits

Molecular quantum-dot cellular automaton (QCA) offers an alternative paradigm for computing at the nano-scale. QCA circuits require an external clock which can be generated using a network of submerged electrodes to synchronize information flow and provide the required power to drive the computation. In this paper, the effect of electrode separation and applied potential on the likelihood of different QCA cell states of molecular cells located above and in between two adjacent electrodes is analyzed. Using this analysis, estimates of operational ranges are developed for the placement, applied potential, and relative phase between adjacent clocking electrodes to ensure that only those states that are used in the computation are energetically favorable. Conclusions on the trade-off between cell size, cell-to-cell distance, and applied clocking potential are drawn and the temperature dependence of the operation of fundamental QCA building blocks is considered.     

A novel quantum-dot cellular automata CLB of FPGA

Quantum-dot cellular automata (QCA) is a promising, emerging nano-technology based on single electron effects in quantum dots and molecules. This paper presents design, implementation and simulation of a configurable logic block for a field programmable gate arrays (FPGA) by QCA. Previous works focus on QCA-based FPGA that have fixed logic and programmable interconnection or programmable logic and fixed interconnection; however, proposed structures in this paper have programmable logic and programmable interconnection. The presented look-up table implemented with novel structure which has been allowed as frequently as the read/write operation occurs, also acts as a pipeline. In this paper, we presented novel decoders and multiplexers and implemented with QCA, designed with the minimum number of majority gates and cells. Finally, a new configurable logic block (CLB) is designed, implemented and simulated in the QCA, which used signal distribution network method to avoid the coplanar problem of crossing wires. Also, QCADesigner software is used for detailed layout and QCADesigner attend with HDLQ verilog are used for circuit simulation. The proposed CLB is simulated with programming by the QCADesigner software. The area and delay of QCA-based CLB presented in this paper compared to the CLB based on CMOS, nanomaterial and CNT (32 nm). Results show that proposed CLB will do the task with a minimum clock and can be configured as a FPGA.     

Performance analysis of all optical-based quantum internet circuits

Journal of Computational Electronics - A Quantum dot implanted within a double-sided optical microcavity is considered and investigated as a critical component for all optical-based quantum...     

New approaches for modeling and simulation of quantum-dot cellular automata

In order to further development of the microelectronic systems and to achieve the circuits with higher speed, higher density and lower power consumption, new technologies to replace the conventional CMOS technology must be introduced. Quantum-dot cellular automata (QCA) is an emerging nanotechnology that provides a new method for computation at the nanoscale regime. In this paper, two methods e.g. artificial neural network and a mathematical algorithm based on the QCA cell–cell response function named Tansig method are used for the modeling and simulation of QCA circuits at the cell level. The accuracy and performance of the proposed methods are analyzed through few circuits. The results of these two approaches are compared with each other and QCADesigner software. The results show the feasibility and acceptable accuracy of these types of simulations. Also, these methods enable the simulation of large QCA circuits at the cell level with acceptable precision in a short time with the ability to implement in other circuit simulators such as HSPICE and so on.     

基于元胞自动机的流域水土流失时空动态变化研究

本文提出一种结合元胞自动机的区域水土流失预测模型,采用线性神经网络方法预测区域土地利用总体变化趋势;同时考虑道路、商服中心对城市土地利用覆盖的影响,制定元胞自动机转换规则,预测区域未来土地利用覆盖情况,预测精度达到72%。最后,将CA预测数据作为变量输入通用土壤流失方程,预测区域水土流失情况。并以武汉市东湖流域为例对其水土流失问题进行了现状分析及预测,为其水土流失整治提供参考。     

一种基于多目标遗传算法的CA加权测试生成方法

本文介绍一种内建自测试总体优化的测试生成方法,首先对细胞自动机的特点进行了介绍,还分析了细胞自动机结构的邻居关系和加权测试序列相关性,最后本文用多目标遗传算法来设计这种测试生成方法,并应用ISCAS＇85基准电路来验证此方法。通过对具体例子的各项指标比较,说明了这种内建自测试总体优化的测试生成方法比传统的测试方法具有优越性。     

Towards the design of hybrid QCA tiles targeting high fault tolerance

The increasing fabrication cost of CMOS-based computing devices and the ever-approaching limits of their fabrication have led to the search for feasible options with high device density and low power waste. Quantum-dot cellular automata (QCA) is an emerging technology with such potential to match the design target beyond the limits of state-of-the-art CMOS. But nanotechnologies, like QCA are extremely susceptible to various forms of flaws and variations during fabrication at nano scale. Thus, the exploration of ingenious fault tolerant structure around QCA is gaining high importance. This work targets a new robust QCA tile structure hybridizing rotated and non-rotated cell together resulting lesser kink energy. Different QCA logic primitives (majority/minority logic, fanout tiles, etc.) are made using such hybrid cell structure. The functional characterization using the kink energy and the polarization level of such QCA structures under different cell defects have been thoroughly investigated. The results suggest that the proposed QCA logic primitives have achieved high fault tolerance of 97.43 %. Also, 100 % fault tolerance can be ascertained if the proposed logic circuit drives the correct output with the application of \(\langle \)001, 011\(\rangle \) as a primitive test vector only. A comparative performance of the proposed logic over existing structure makes it more reliable.     

Ballistic quantum transport using the contact block reduction (CBR) method

The contact block reduction (CBR) method is a variant of the nonequilibrium Green’s function formalism and can be used to describe quantum transport in the ballistic limit very efficiently. We present a numerical implementation of a charge self-consistent version of the CBR algorithm. We show in detail how to calculate the electronic properties of open quantum systems such as the transmission function, the local density of states and the carrier density. Several 1D and 2D examples are provided to illustrate the key points. The CBR method is a very powerful tool to tackle the challenge of calculating transport in the ballistic limit for 3D devices of arbitrary shape and with an arbitrary number of contacts.     

A unified and efficient approach for determining Thevenin (Norton) equivalent circuits

A unified and efficient approach for the determination of the Thevenin (Norton) equivalent circuit is presented, in which two parameters of the Thevenin (Norton) equivalent circuit can be obtained simultaneously and systematically, and it is not required to set all independent sources to zero.<>     

Simulation of tree propagation in polyethylene including air void by using cellular automata: The effect of space charges

In the present paper tree propagation in polyethylene is simulated with the aid of cellular automata. The case of small air voids is studied for various space charge values. The influence of positive space charge is investigated and the simulation shows that tree propagation is strongly affected by the space charge density. The role of homocharges in the propagation of tree structures is studied and the results of the simulation are in qualitative agreement with published experimental data.     

Transient electromagnetic phenomena in the secondary circuits ofvoltage and current transformers in GIS (measurements and calculations)

The paper presents numerical and experimental evaluation of the transient behavior of gas insulated substations (GIS). The electrical equivalent circuits chosen to represent the main components of GIS are implemented in the Electromagnetic Transients Program (EMTP). The effect of mutual couplings between phases are included in the model, which is of importance for analyzing a modern GIS, containing three-phases in one encapsulation. With the help of this model the generation and propagation of transients inside GIS have been evaluated with regard to transient overvoltages in the secondary circuits of voltage- and current transformers. The established model results have been successfully verified experimentally for a 123 kV GIS     

Microscopic photoluminescence spectroscopy of self-organizedCdSe-ZnSe quantum dots grown on the GaAs (110) cleaved surface

Self-organized CdSe-ZnSe quantum dots (QDs) were fabricated on the cleavage-induced GaAs (110) surface in ultra high vacuum (UHV) by molecular beam epitaxy (MBE). CdSe layer showed the Stranski-Krastanow (S-K) growth mode, QWs and QDs emissions originated from the wetting layer and island structures, respectively, were observed in photoluminescence (PL) spectra. This is a evidence of S-K type where island structures are self-formed on the two-dimensional wetting layer as a result of the transition of the growth mode. The state filling effect in the QDs was also observed by employing excitation power dependence on the PL intensity. By using the microscopic PL spectroscopy, the broad PL peak of QDs was resolved into a number of sharp peaks. These peaks are attributed to the recombination of excitons localized at the individual QDs indicating that the fabricated CdSe islands have quasi-zero-dimensional δ-function like density of states     

General overview of steady-state (small signal) stability in bulk electricity systems : A North American perspective

The most recent North American concepts of stability are discussed. Conditions in which problems of small disturbance stability have been encountered or have been noted to occur in North America, are then reviewed. Comments are made on small disturbance stability engendered by continuously acting, high gain, excitation systems, and this is followed by a review of analytical approaches considered pertinent to the study of this type of stability. The paper concludes with some specific examples of analysis applied to the Ontario Hydro bulk power system.     

On the steady-state analysis of the inverter-fed induction motor

Contents The analysis of the induction motor based on the signal flow graphs is carried out. It is shown that the state transition matrix can be determined in a systematic and straightforward way using Mason's gain formula. This method is found computationally very much superior to other methods available in the literature. There is a considerable reduction in the CPU time. The presence of an input signal also does not pose any problems, as inherently the transition signal flow graph includes its effect also.

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Das stationäre Verhalten der stromrichter-gespeisten Asynchronmaschine

Übersicht Es wird in der vorliegenden Arbeit das stationäre Verhalten der stromrichter-gespeisten Asynchronmaschine auf Grund des Signalflußdiagramms untersucht. Die Anwendung der Masonschen Regel liefert unmittelbar die, State Transition Matrix' mit einem CPU-Zeitaufwand, der geringer ist, als der der in der Literatur bekannten Methoden. Beliebige Eingangssignale lassen sich in einfacher Weise behandeln, da diese im Signalflußdiagramm repräsentiert werden können.

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List of Symbols i _ds,i _qs direct and quadrature axis currents of stator - i _dr,i _qr direct and quadrature axis currents of rotor - i _dr(0),i _qs(0) initial values of d-q currents of stator - i _dr(0),i _qr(0) initial values of d-q currents of rotor - I _ds(s),I _qs(s) Laplace transforms of d-q currents of stator - I _dr(s),I _qr(s) Laplace transforms of d-q currents of rotor - L _s,L _r Self inductances of stator and rotor - M Mutual inductance between stator and rotor - R _s,R _r Resistance per phase of stator and rotor windings - R ₁,R ₂,R ₃,R ₄ Roots of characteristic equation - V _ds V _qs Direct and quadrature components of stator voltage - _ds, _qs Direct and quadrature components of stator flux linkages - _dr, _qr Direct and quadrature components of rotor flux linkages - _s Synchronous angular velocity - _r Rotor angular velocity - T _d Torque developed     

Predicting the steady-state performance of a switched reluctancemachine

Modeling and computational techniques for predicting the steady-state characteristics of a switched reluctance motor (SRM) drive over a wide range of torque/speed variations, dealing with both current- and angle-controlled modes of operation, are presented. Special techniques are used in the mesh modeling of the high gradient field within the airgap and in the postprocessing of the field solution to ensure good accuracy in the motor parameters and static characteristics that are essential to producing steady-state predictions that agree favorably with experimental results. The instantaneous torque and flux linkage, inductances, and back electromotive force are obtained from accurately calculated static characteristics of the motor using surface interpolation techniques     

Ansys软件在无刷直流电动机电感计算中的应用

应用Ansys软件对11 kW无刷直流电动机,电感进行分析计算,求出电机A、B两相绕组的自感和互感,绘出电感的图形曲线,并分析绕组电感时变性和周期性的原因,为无刷直流电动机的精确建模和仿真提供了必要的自感和互感参数值,提高了电机设计和分析的准确性,具有有一定的工程应用价值.     

A generalized approach for the steady-state analysis of resonantinverters

A generalized approach is presented for the steady-state analysis of resonant inverters which leads to the selection of an optimum scheme for a particular application. Six load-commutation schemes are combined into a single commutation scheme, referred to as a generalized load-commutation circuit, and the steady-state analysis for the circuit with RL load is presented using a Fourier series approach in the continuous-current mode. The equations for different load-commutation circuits are obtained as the particular cases of the generalized configuration. This type of unified approach simplifies the method of analysis for different commutation schemes and eliminates the need for the separate analysis of different schemes. Also, in a computer program, the results for a particular configuration can be obtained simply by opening or shorting the nonrequired commutating components of the generalized scheme. The method of analysis is used to select resonant inverter schemes with resistive load, based on certain constraints. Experimental results are presented for the selected schemes to support the theory     

用圆图法计算电动机工作特性的微机计算程序

1引言 GB1032-85规定:如限于设备对立式和300kW以上的电动机或大于8极的200kW以上的电动机,允许按圆图计算法求取额定功率时的工作特性.但现实情况是圆图计算法的计算过程比较复杂,人工计算时工作量很大.因此,我们编制了用圆图计算法计算电动机工作特性的微机计算程序以解决这一难题.该程序用VB语言编制,界面友好,操作简洁.以下是该程序的运行界面及使用说明.     

On the steady-state determination of networks containing magnetic nonlinearities

Contents In this paper the Newton-Raphson algorithm is applied to obtain the steady-state solution of networks with a weak damping, containing nonlinear reactive elements. The fast obtaining of the steady-state solution is demonstrated in an example, in which the phenomenon of ferroresonance is treated because of its very nonlinear character.

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Über die Bestimmung des stationären Zustandes von Netzwerken mit magnetischen Nichtlinearitäten

Übersicht In diesem Aufsatz wird das Newton-Verfahren verwendet für die beschleunigte Berechnung des stationären Zustands von Netzwerken mit nichtlinearen magnetischen Elementen und einer geringen Dämpfung. Diese Methode wird anhand eines Beispieles erläutert.Dieses Beispiel ist Ferro-Resonanz-Erscheinungen gewidmet, da diese einen stark nichtlinearen Charakter aufweisen.