空间电荷波传播特性的PIC粒子模拟

采用周期性边界条件的二维准静电PIC粒子模拟程序对空间电荷波的产生及传播过程进行了数值模拟,给出了静止和一维定向漂移空间电荷波的产生及传播特性随等离子体参数变化的关系,通过单电子跟踪的方法,得到了波动过程带电粒子的空间状态的变化规律。其结果,将作为进一步实现空间电荷波与电磁波产生波一波相互作用过程模拟的基础。     

Single-electron random-number generator (RNG) for highly secure ubiquitous computing applications

Since the security of all modern cryptographic techniques relies on unpredictable and irreproducible digital keys generated by random-number generators (RNGs), the realization of high-quality RNG is essential for secure communications. In this report, a new RNG, which utilizes single-electron phenomena, is proposed. A room-temperature operating silicon single-electron transistor (SET) having nearby an electron pocket is used as a high-quality, ultra-small RNG. In the proposed RNG, stochastic single-electron capture/emission processes to/from the electron pocket are detected with high sensitivity by the SET, and result in giant random telegraphic signals (GRTS) on the SET current. It is experimentally demonstrated that the single-electron RNG generates extremely high-quality random digital sequences at room temperature, in spite of its simple configuration. Because of its small-size and low-power properties, the single-electron RNG is promising as a key nanoelectronic device for future ubiquitous computing systems with highly secure mobile communication capabilities.     

Towards controlling larger quantum systems: from laser cooling toquantum computing

Laser-cooling techniques offer novel opportunities in the generation and manipulation of entangled quantum states. Atoms trapped in infrared mesoscopic optical lattices are presented as attractive candidates for both the production of highly entangled states and quantum logic experiments. Recent experimental work on the realization of such a lattice, based on atoms trapped in the antinodes of an infrared standing wave near 10.6 μm, is reviewed. This culminates in the individual lattice sites being resolved with an optical microscope. Finally, with the aim of achieving greater control over molecules, a matter-wave interferometer is proposed, in which the probability for absorption of photon momenta depends on the particle velocity, rather than on the absolute laser detuning from a particular optical transition. This scheme has prospects for the laser cooling of both atoms and molecules     

基于量子粒子群算法的移动节点覆盖优化

提出了基于量子粒子群的无线传感器网络覆盖优化算法.由于在量子空间中粒子满足集聚态性质完全不同,使得该算法可以在整个可行区域内搜索.全局搜索能力远远优干基本粒子群,克服了粒子群算法容易陷入局部最优的缺点.仿真结果表明,该算法比基本粒子群算法拥有更好的覆盖优化效果。     

三目标柯西粒子群算法的电力系统无功优化

通过建立有功网损最小、电压偏差最小和静态稳定电压裕度最大的三目标无功优化模型。提出柯西粒子群算法,并针对IEEE14节点系统进行三目标电力系统无功优化。当种群多样性较差时,通过对交叉的粒子进行柯西变异从而扩大搜索空间,提高种群多样性,防止出现过早的收敛,进而避免了算法陷入局部最优解的问题,同时也提高了收敛速度。通过数据测试和比较柯西粒子群算法在收敛速度、精度、全局搜索能力上均优于常规差分进化算法和常规粒子群算法。其结果验证了该模型和算法的有效性,为电力系统安全经济运行提供了参考。     

Single-electron winner-take-all network

A winner-take-all (WTA) single-electron neuron is developed for the first time. This new single-electron circuit is proposed in order to implement a WTA neural network with lateral inhibition architecture. An expression for the neuron's activation function is presented. Furthermore, a dot pattern recognition task is successfully performed by the implemented network considering effects such as offset charges and co-tunnelling.     

Fabrication method for IC-oriented Si single-electron transistors

A new fabrication method for Si single-electron transistors (SETs) is proposed. The method applies thermal oxidation to a Si wire with a fine trench across it on a silicon-on-insulator substrate. During the oxidation, the Si wire with the fine trench is converted, in a self-organized manner, into a twin SET structure with two single-electron islands, one along each edge of the trench, due to position-dependent oxidation-rate modulation caused by stress accumulation. Test devices demonstrated, at 40 K, that the twin SET structure can operate as two individual SET's. Since the present method produces two SET's at the same time in a tiny area, it is suitable for integrating logic circuits based on pass-transistor type logic and CMOS-type logic, which promises to lead to the fabrication of single-electron logic LSIs     

Analog Computation Using Single-Electron Circuits

Analog computation is a processing method that solves a given problem by utilizing an analogy of a physical system to the problem. An idea is presented here for relating the behavior of single-electron circuits to analog computation. As an instance, a method is proposed for solving a combinatorial problem, the three-colorability problem, by using the properties of single-electron circuits. In problem solving, a single-electron circuit is constructed that is analogous to a given problem; then, through an annealing procedure, the circuit is made to settle down to its minimun energy state. The correct solution to the problem can be obtained by checking the final arrangement of electrons in the circuit. Analog computation is a promising architecture for single-electron computing systems.     

Classification of single-electron devices

A classification based on the principles identified in this paper is proposed for single-electron devices. A large number of currently known nanoelectronic devices of the type considered here can be described on the basis of this classification. This classification can be used to propose new single-electron devices. Fiz. Tekh. Poluprovodn. 33, 1388–1394 (November 1999)     

基于自适应粒子群算法的目标定位方法研究

针对现有定位求解算法复杂和标准粒子群算法易陷入局部最优的缺点,提出了一种基于自适应粒子群算法的目标定位方法.该方法在迭代过程中指数更新惯性权重,择优选择粒子,并根据种群适应度方差值自适应地调整变异概率的大小,增强算法跳出局部最优的能力.仿真结果表明该方法能有效地提高目标的定位精度,在随机噪声干扰方差为0.5的条件下,定位均方误差不超过0.8m.     

Electronic transport in silicon nanocrystals and nanochains

Si nanocrystals and nanochains, prepared by material synthesis, provide a means to define nanoscale devices using growth rather than lithographic techniques. Electronic transport in thin films of Si nanocrystals is influenced strongly by single-electron charging and quantum-confinement effects, and by the grain boundary regions between nanocrystals. This paper reviews electronic transport mechanisms in Si nanocrystal materials. These include thermionic emission of electrons across grain boundaries, space charge limited current, hopping transport, and single-electron charging effects. The fabrication of single-electron devices in Si nanocrystal thin films and nanochains is considered, particularly with regards to their operation at room temperature.     

粒子对算法在图像矢量量化中的应用

本文给出了一种新的图像矢量量化码书的优化设计方法——粒子对算法.在传统粒子群优化(Particle Swarm Optimization,PSO)算法的基础上,用两个粒子构成了群体规模较小的粒子对,在码书空间中搜索最佳码书.在每次迭代运算中,粒子对按先后顺序执行PSO算法中的速度更新、位置更新操作和标准LBG算法,并用误差较大的训练矢量代替越界的码字.此算法避免粒子陷入局部最优码书,较准确地记录和估计每个码字的最佳移动方向和历史路径,在训练矢量密集区域和稀疏区域合理地分配码字,从而使整体码书向全局最优解靠近.实验结果表明,本算法始终稳定地取得显著优于FKM、FRLVQ、FRLVQ-FVQ算法的性能,较好地解决了矢量量化中初始码书影响优化结果的问题,且在计算时间和收敛速度方面有相当的优势.     

集成化单电子器件研究进展

传统MOSFET结构正以较快的发展速度接近其物理极限,而单电子器件将成为新型的高性能集成化器件结构。本文采用量子点及其库伦阻塞效应等概念对单电子器件的工作原理进行了系统分析,并介绍了单电子器件在存储器和高灵敏度静电计方面的应用,最后指出了单电子器件的新发展方向及所面临的问题。     

Binary-decision-diagram device

The device proposed here for future LSI's is based on a concept different from the Boolean equations usually used for representing digital functions. The unit function of this device is simple two-way switching and can be implemented utilizing various physical effects, such as optical switching, electron-wave modulation, and single-electron transport. Several possible device structures are presented, and a simulated result for a single-electron device is described     

Quantum Hopfield Network Using Single-Electron Circuits—A Novel Hopfield Network Free from the Local-Minimum Difficulty

The concept of the quantum Hopfield network is proposed with examples of its network construction, which uses single-electron circuits. In this network, two or more threshold elements can change their outputs simultaneously in a form of coherent combination. This can be put into physical form by utilizing the co-tunneling phenomenon found in single-electron circuits. In the quantum Hopfield network, a state transition with a large Hamming distance can occur and therefore the local-minimum difficulty disappears; in consequence the global-minimum energy state can always be achieved. Use of this property made possible the development of novel computation devices that solve combinatorial problems without hindrance from the local-minimum difficulty.     

一种精英反向学习的粒子群优化算法

为解决传统粒子群优化算法易出现早熟的不足,提出了精英反向学习策略,引入精英粒子,采用反向学习生成其反向解,扩大搜索区域的范围,可增强算法的全局勘探能力.同时,为避免最优粒子陷入局部最优而导致整个群体出现搜索停滞,提出了差分演化变异策略,采用差分演化算法搜索最优粒子的邻域空间,可增强算法的局部开采能力.在14个测试函数上将本文算法与多种知名的PSO算法进行对比,实验结果表明本文算法在解的精度与收敛速度上更优.     

Consideration of the “island” background charge in single-electron transistor simulation

Three approximations of the “island” background charge are described within the proposed 2D numerical model of the metal single-electron transistor. These approximations fit the experimental data well when calculating I–V characteristics of single-electron transistors according to the model developed in many cases. The validity of these approximations is exemplified by specific calculations of I–V characteristics.     

Characteristics of dielectric loaded and covered circular waveguide phased arrays

The use of dielectric materials for the hardening and matching of phased-array antennas in recent years has shown that a more complete understanding of the effects of these materials upon the array performance is necessary. The characteristics of fully loaded, plugged, and sheath covered circular waveguide phase arrays are analyzed and discussed. Numerical solutions of the boundary-value problem are verified by experimental and convergence tests. Particular emphasis is placed on the study of (forced) surface wave resonance effects. Three different cases for surface wave resonances were obtained. These include the case in which surface wave resonances are present in the absence of dielectrics, the case in which they are trapped by the presence of dielectric plugs, as well as the case in which waves are trapped by the presence of a dielectric sheath. The surface wave resonance due to the plug is shown to vanish for certain "bandpass" ranges of plug thickness which repeat periodically for a single trapped waveguide mode. On the other hand, the surface wave trapped in the sheath exhibits no "bandpass" characteristics. Instead, multiple surface wave resonances occur with increasing sheath thickness. Finally, the surface wave resonances observed here appear at isolated points in the scan plane.     

A Hybrid of Cooperative Particle Swarm Optimization and Cultural Algorithm for Neural Fuzzy Networks and Its Prediction Applications

This study presents an evolutionary neural fuzzy network, designed using the functional-link-based neural fuzzy network (FLNFN) and a new evolutionary learning algorithm. This new evolutionary learning algorithm is based on a hybrid of cooperative particle swarm optimization and cultural algorithm. It is thus called cultural cooperative particle swarm optimization (CCPSO). The proposed CCPSO method, which uses cooperative behavior among multiple swarms, can increase the global search capacity using the belief space. Cooperative behavior involves a collection of multiple swarms that interact by exchanging information to solve a problem. The belief space is the information repository in which the individuals can store their experiences such that other individuals can learn from them indirectly. The proposed FLNFN model uses functional link neural networks as the consequent part of the fuzzy rules. This study uses orthogonal polynomials and linearly independent functions in a functional expansion of the functional link neural networks. The FLNFN model can generate the consequent part of a nonlinear combination of input variables. Finally, the proposed FLNFN with CCPSO (FLNFN-CCPSO) is adopted in several predictive applications. Experimental results have demonstrated that the proposed CCPSO method performs well in predicting the time series problems.     

基于单电子晶体管的类双涡卷混沌电路

基于单电子晶体管的特性,利用电流模式技术,提出一种单电子晶体管(SET)的混沌电路实现方法.全SET混沌电路的实现,更加便于用集成电路实现,并降低了工作电压,提高了工作频率带宽.利用SPICE对电路进行仿真,结果验证了电路实现的正确性.