负阻抗变换器的实现与应用研究

章介绍了由一级运算放大器实现的电流反向型负阻抗变换器，以及它与无源元件联接后，在改变阻抗大小和性质，用作阻抗逆变器和构成负内阻电压源等方面的应用。     

正弦激励非零状态下的二阶电路暂态过程的研究

对正弦激励非零状态下的PLC串二阶电路的暂态过程进行了研究，给出了电路在接通正弦电源后直接进入稳态响应的条件，分析了暂态过程中出现的过电压、过电流现象。     

高压脉冲幅值测量电路的误差分析及改进电路

为了提高高压脉冲幅值的测量精度,对高压脉冲幅值测量电路的电路误差进行了计算,分析了测量电路产生误差的原因。设计一种单脉冲电压正峰值保持电路对高压脉冲幅值测量电路进行了改进。主要采用单脉冲保持电路增大电容器的电荷保持时间,减少漏电。电路经过改进后,减小了原电路的高压脉冲幅值测量误差,为实际应用打下良好的基础。     

负阻效应的存在性研究及NIC在振荡实验中的设计

对负阻效应在实际几种元器件中的存在及特性进行了研究和证明,重点研究了利用运算放大器构成的负阻抗变换器的变换阻抗性质。并运用负阻抗变换器的负阻作用对现有的LC阻尼振荡实验进行了改进并给出了具体的电路,使实验结果更加多样化。     

负阻效应的存在性研究及MC在振荡实验中的设计

对负阻效应在实际几种元器件中的存在及特性进行了研究和证明,重点研究了利用运算放大器构成的负阻抗变换器的变换阻抗性质.并运用负阻抗变换器的负阻作用对现有的LC阻尼振荡实验进行了改进并给出了具体的电路,使实验结果更加多样化.     

几种电路分析方法的简单讲解

本文作者针对电路分析中的六种分析方法：电源的等效变换分析法、支路电流法、结点电压法、叠加原理、戴维宁定理、诺顿定理,通过用同一道例题使用不同的方法来分别求解,以帮助学生理解各种分析方法的内容,掌握各种分析方法的特点与注意事项,并能灵活应用。     

用类比法讨论二阶电路的特点

本文采用类比方法，借助于普通物理中振动章节，讲述二阶电路中电压μ＿ｃμ＿Ｌ与电流ｉ之间关系及电路的特点，同时加强普通物理与电路教学的衔接，丰富教材内容。     

巧用内阻的变形式定量分析动态电路

在恒定电路中,分析动态电路主要方法是定性分析,对一些较难的题目,由定性分析得出答案,自己总觉得心里不踏实。如果把电源内阻的测量式,     

从能量和功的角度讨论等幅振动

本文主要从能量转化和外力做功的比较简谐振动和稳态受迫振动,并由外力做功导出稳态受迫振动一个周期内平均动能和平均势能的大小关系由相位决定。     

模拟电子技术教学中电路理论的应用

电路的分析和计算方法有多种方式,应用电路理论中的迭加原理和代维南定理,对模拟电子技术中的基本放大电路静态和动态进行了分析.     

非线性振荡电路的混沌分析

分析了具有混沌动力学特征的非线性三阶自治电路，给出了混沌电路中非线性电阻的构造方法，通过EWB软件对混沌电路进行了计算机仿真，实际硬件电路板测试得到混沌吸引子、倍周期分岔、周期性窗口等预期分析结果，此结果对深入研究混沌理论及混沌的同步和控制有积极借鉴作用。     

正弦波振荡电路的分析方法探析

结合教学实践的体会,对正弦波振荡电路的分析方法与过程进行了详细的探讨,为学习者建立一种清晰、逻辑的分析电路思维能力。     

基于Multisim的单失谐振幅鉴频电路仿真

利用Multisim软件对单失谐振幅鉴频电路进行仿真分析,通过改变电路元件参数,对比分析了感性失谐和容性失谐波形的特点,以及二极管包络检波器正常检波情况、惰性失真现象。通过仿真实验,可以生动、直观地展现仿真结果,增强学生的感性认识,加深学生对概念和原理的理解。实践证明,这种教学方法有利于调动学生的学习积极性和主动性,明显改善了教学效果。     

基于Multisim 10.1的抗载波DSB调幅电路的仿真分析

利用Multisim10.1软件对抗载波双边带调幅电路的仿真分析,观察双边带(DSB)调幅波的波形变化规律,采用虚拟频谱仪的曲线分析了载波和上下边频的频率及电压增益,结果与理论分析吻合。通过实例验证了合理地将Multisim10.1引入高频电路实验教学后,可将抽象、枯燥的高频电路理论教学变得具体和生动,有利于提高高频电子线路理论课的教学质量。     

基于"在系统可编程模拟"器件的滤波器的实现

该文介绍了应用3个运算放大器实现双二阶型函数的电路,从而设计有源滤波器;即应用"在系统可编程模拟"器件(ispPAC10)基本单元电路的功能构成双二阶滤波器,在PAC-Designer软件的开发平台下,实现有源滤波器的设计、仿真、下载.     

Blocking of first- and second-order autoshaping in pigeons

In Experiment 1, the development of autoshaped pecking to a keylight signaling food was blocked if the keylight was presented only in conjunction with another stimulus already established as a signal for food, even though the blocking stimulus (either an overhead light or a train of clicks) never elicited pecking itself. In Experiment 2, pigeons came to peck a white keylight which signaled the presentation of a red keylight which had earlier been established as a first-order signal for food, but this second-order autoshaping was blocked if the white keylight was presented only in conjunction with the houselight or clicker which had previously signaled the presentation of the first-order stimulus. Second-order autoshaping was thus blocked in the same way as was first-order autoshaping.     

Temporal integration in second-order conditioning and sensory preconditioning

Lick suppression experiments with rats revealed that the magnitude of both second-order conditioning (Experiment 1) and sensory preconditioning (Experiment 2) was superior when that conditioning was based on backward (US→CS) relative to forward (CS→US) first-order pairings of a CS and US. The superiority of backward relative to forward first-order conditioning on suppression to the higher order cues can be understood by assuming that the magnitude of higher order conditioning was determined by a memory representation of the higher order cues that provided information about the expected temporal location of the US. The results suggest that temporal information such as order between paired CSs and USs was encoded, preserved, and integrated with memory for the higher order stimuli. The relevance of these findings to memory integration in Pavlovian learning, the temporal coding hypothesis (Barnet, Arnold, & Miller, 1991; Matzel, Held, & Miller, 1988), backward excitatory conditioning, and the associative structure that underlies second-order Pavlovian fear conditioning are discussed.     

Associative structure of second-order conditioning in humans

Second-order conditioning (SOC; i.e., conditioned responding to S2 as a result of S1–US pairings followed by S2–S1 pairings) is generally explained by either a direct S2→US association or by an associative chain (i.e., S2→S1→US). Previous research found that differences in responses to S2 after S1 was extinguished often depended on the nature of the S2–S1 pairings (i.e., sequential or simultaneous). In two experiments with human participants, we examined the possibility that such differences result from S1 evoking S2 during extinction of S1 following simultaneous but not sequential S2–S1 pairings. This evocation of S2 by S1 following simultaneous pairings may have paired the evoked representation of S2 with absence of the outcome, thereby facilitating mediated extinction of S2. Using sequential S2-S1 pairings, both Experiments 1 and 2 failed to support this account of how extinction of S1 reduced responding to S2. Experiment 1 found that extinguishing S1 reduced responding to S2, while extinguishing S2 had little effect on responses to S1, although forward evocation of S1 during extinction of S2 paired the evoked representation of S1 with absence of the outcome. In Experiment 2, evocation of S2 during S1 nonreinforced trials was prevented because S2–S1 pairings followed (rather than proceeded) S1-alone exposures. Nevertheless, responding to S2 at test mimicked S1 responding. Responding to S2 was high in the context in which S1 had been reinforced and low in the context in which S1 had been nonreinforced. Collectively, these experiments provide additional support for the associative-chain account of SOC.     

Some determinants of second-order conditioning

In a Pavlovian conditioning situation, an initially neutral stimulus may be made excitatory by nonreinforced presentations in compound with an established conditioned excitor [i.e., second-order conditioning (SOC)]. The established excitor may be either a punctate cue or the training context. In four conditioned suppression experiments using rats, we investigated whether SOC phenomena parallel other cue interaction effects. In Experiment 1, we found that the response potential of a target stimulus was directly related to the intertrial interval when SOC was mediated by a punctate cue, and inversely related to the intertrial interval when SOC was mediated by the training context. Experiment 2 demonstrated that punctate- and context-mediated SOC are oppositely affected by posttraining context extinction, and Experiments 3 and 4 demonstrated that context- and punctate-mediated SOC are differentially affected by conditioned stimulus (Experiment 3) and unconditioned stimulus (Experiment 4) preexposure treatments. These findings parallel phenomena in conditioned inhibition and cue competition situations.     

First- and second-order configural sensitivity for greeble stimuli in baboons

Previous studies on nonhuman primates have shown inconsistencies in their processing of first- and secondorder relational properties of facial stimuli. Using greeble stimuli sharing configural properties with faces, this study assessed configural processing in baboons. Five baboons were trained to recognize a positive stimulus among pairs of greebles in a two-alternative forced choice task. They were then tested with new stimulus pairs involving either a first-order version, with modifications in global qualitative spatial relations, or a second-order version, with modifications of finer spatial relations. Performance remained above chance in all test conditions, including when only second-order cues were available, but it was higher for first-order trials. It is proposed that an extensive training with greebles led to the processing of second-order relational properties. These results demonstrate that configural sensitivity is not restricted to faces in baboons and suggest that a common mechanism may support configural processing for face and nonface stimuli.