摘要：This paper proposes the current search (CS) metaheuristics conceptualized from the electric current flowing through electric networks for optimization problems with continuous design variables. The CS algorithm possesses two powerful strategies, exploration and exploitation, for searching the global optimum. Based on the stochastic process, the derivatives of the objective function is unnecessary for the proposed CS. To evaluate its performance, the CS is tested against several unconstrained optimization problems. The results obtained are compared to those obtained by the popular search techniques, i.e., the genetic algorithm (GA), the particle swarm optimization (PSO), and the adaptive tabu search (ATS). As results, the CS outperforms other algorithms and provides superior results. The CS is also applied to a constrained design of the optimum PID controller for the dc motor speed control system. From experimental results, the CS has been successfully applied to the speed control of the dc motor.

摘要：To miniaturize a very low level dc current amplifier and to improve its output response speed, the switched capacitor negative feedback circuit (SCNF), instead of the conventionally used high-ohmage resistor, is presented in this paper. In our system, a switched capacitor filter (SCF) and an offset controller are also used to decrease vibrations and offset voltage at the output of the amplifier using SCNF. The theoretical output voltage of the very low level dc current amplifier using SCNF is obtained. The experimental results show that the unnecessary components of the amplifier’s output are much decreased, and that the response speed of the amplifier with both the SCNF and SCF is faster than that using high-ohmage resistor.

摘要：An application of the current search (CS), one of the most efficient metaheuristic optimization search techniques, to design the PIDA (proportional-integral-derivative-accelerated) controllers is proposed in this paper. The CS is applied to search for the optimum PIDA controller’s parameters. The obtained controllers are tested against nine benchmark systems collected by ?sstr?m and H?gglund considered as the hard-to-be-controlled plants and an automatic voltage regulator (AVR) system. As results, the optimum PIDA controllers can be successfully obtained by the CS and the responses of controlled systems are very satisfactory.

摘要：This paper presents a method for designing a class of countermeasures for DPA attacks based on attenuation of current variations. In this class of countermeasures, designers aim at decreasing the dynamic current variations to reduce the information that can be extracted from the current consumption of secure microsystems. The proposed method is based on a novel formula that calculates the number of current traces required for a successful DPA attack using the characteristics of the microsystem current signal and the external noise of the measurement setup. The different stages of the proposed method are illustrated through designing an example current flattening circuit. Meanwhile validity and applicability of the proposed formula is verified by comparing theoretical results with those obtained experimentally for the example circuit. The proposed formula not only estimates the required level of attenuation for a target level of robustness defined by design requirements, it also predicts the effectiveness of a countermeasure using simulation results therefore dramatically reducing the time to design of secure microsystems.

摘要：In the field of analog VLSI design, current conveyors have reasonably established their identity as an important circuit design element. In the literature published during the past few years, numerous application have been reported which are based on a variety of current conveyors. In this paper, an oscillator circuit has been proposed. This oscillator is designed using a single positive type second generation current controlled current conveyor (CCCII+). A CCCII has parasitic input resistance on it’s current input node. This resistance could be exploited to reduce circuit complexities. Thus in this accord, a novel oscillator circuit is proposed which utilizes the parasitic resistance of the CCCII+ along with a few more passive components.

摘要：A high power buck-boost switch-mode LED driver delivering a constant 350 mA with a power efficient current sensing scheme is presented in this paper. The LED current is extracted by differentiating the output capacitor voltage and maintained by a feedback. The circuit has been fabricated in a standard 0.35 μm AMS CMOS process. Measurement results demonstrated a power-conversion efficiency over 90% with a line regulation of 8%/V for input voltage of 3.3 V and current output between 200 mA and 350 mA.

摘要：The synthetic making test has been widely used in evaluating the break ability of high-voltage circuit breaker. However, the test research and application are still inadequate, especially in the condition of rated voltage. According to the realistic conditions of test stations in China, a control device based on pre-arcing current detection and phase control is proposed in this paper. A sample of the control device made up of DSP TMS320LF2407A is fabricated, in which the CPLD MAX7064 is used to transmit signals for EMC design. It can be applied in full voltage synthetic making test at a level of 126kV/63kA. The test results show that, it is accurate to control the making phase of the applied voltage, whether the closing is demanded at voltage peak or zero.

摘要：The effects of the composite-collector structure and the δ-doping density in InGaAs/InP DHBT on the Kirk current have been *** effective grade layer in the discretely graded layer goes into the InGaAs setback *** formulas of the maximum doping density,the maximum Kirk current,and the corresponding δ-doping density are derived under different Kirk-effect *** the maximum collector doping density and the maximum Kirk current are dependent on the δ-doping *** opti-mizing the delta doping,the Kirk current density can be greatly increased.

摘要：This study investigates the current situation of the film and television education in primary and secondary schools in China. The purpose is to find out the problems existing in the current film and television education in primary and secondary schools, and give improvement measures. A questionnaire was designed in this study and teachers in 89 primary and secondary schools in Liaocheng City, Shandong Province filled in the questionnaires. A total of 355 valid questionnaires were collected. This study analyzed the survey data, and drawn a series of conclusions about the current situation of film and television education in primary and secondary schools on the basis of data analysis. Based on the results of the survey, some suggestions are given to provide reference for the development of film and television education in primary and secondary schools.

摘要：电解水制氢具有工艺简单、原料来源广泛、无污染、氢气纯度高等优点,是最具发展前景的制氢技术之一.然而电解水制氢存在的最大问题是析氢析氧过程能耗过高,需要添加催化剂降低反应能垒.目前,电催化产氢性能最好的材料依然是价格昂贵且储量有限的贵金属铂基催化剂.发展高效稳定的大电流密度制氢非贵金属催化剂,对于氢气的规模化制备和商业化应用意义重大.本工作采用三维导电泡沫镍为自支撑电极材料,引入钼源和硫源构建高活性催化析氢Mo-Ni-S体系.通过水热反应和退火处理,在泡沫镍基底上制备得到了具有高担载量、细长浓密的Mo S2/Ni3S2同轴异质结构纳米线.催化剂结构设计方面,在水热反应过程中创新性地引入表面活性剂(P123),调控催化剂形貌,增加了活性位点数目.在组分调控方面,通过后期退火处理去除低活性物相,增强了催化性能.基于以上结构和组分设计调控,该催化剂在碱性体系下具有优异的大电流密度催化产氢性能,仅需较低过电势便可获得较高的电流密度,同时具有优异的大电流密度产氢稳定性,其电催化产氢性能超过了已报道的众多催化剂.