DOCCⅡ-based electronically tunable current-mode biquadratic filters

A complete state variable current-mode biquadratic filter built by duo-output CCⅡ (DOCCⅡ) with variable current gain is presented. All the coefficients of the filter can be independently tuned through the variable current gain factors of the DOCCⅡ. Based on the principles upon which the general biquadratic filter was constructed, a universal electronically tunable current-mode filter is proposed which implements the low-pass, high-pass, band-pass, band-suppress and all-pass second order transfer functions simultaneously. The PSPICE simulations of frequency responses of second-order filter of are also given.     

调整财税政策适应WTO运行规则

我国加入WTO后的财税政策，尚有许多不适应世贸组织条款要求的问题，因此，作为国家经济调控手段的财税政策，要遵循国际贸易准则，尽快从财税制度立法，政府宏观经济调控，提高市场开放程度和创造国家外企业平等竞争的环境等方面进行调整，以期达到符合WTO运行机制的要求，促进国家对外贸易的正常运转和注意与世界经济一体化的内容接轨。     

计算机辅助化学教学初探

计算机辅助教学是实现教学现代化的一个重要手段，本文对计算机辅助教学在化学教学中的应用作了一些有益的探讨。     

试论实验操作技能的训练和培养

论述了实验操作技能的形成和培养方法 .     

基于操作空间的机械臂自适应模糊鲁棒控制

为提高动力学模型不确定的机械臂系统的跟踪精度, 提出了一种基于操作空间的自适应模糊的鲁棒轨迹跟踪控制方法。考虑存在未知的外部扰动和其他未建模动态, 引入GL(General Linear)矩阵及其乘法算子,利用模糊系统逼近任意非线性函数的能力对机械臂动力学进行前馈补偿, 通过鲁棒控制项抑制建模误差和有界扰动。该方法无需求解机械臂在操作空间的动力学模型。根据Lyapunov 稳定性理论证明了系统的稳定性,并通过仿真实验验证了所设计控制器能达到较好的轨迹跟踪效果。     

认同体验视角下的区域文化旅游产业开发——基于“徽杭古道”的研究

文化认同体验是旅游体验的高级阶段,它有助于区域文化旅游产业的发展。文章以皖浙地区的徽杭古道为研究对象,从游客体验的视角探析了徽杭古道文化旅游项目及其新型旅游业态的开发路径,为徽杭地区共同开发文化旅游资源提供了实证研究基础。     

A Multi-indentured Repairable Inventory System with Limited and Different Diagnostic Repair Resources

This paper describes the characteristics of a single-base repairable inventory system and multi-indenture structure with communality and redundancy. At the base, there are a working field that has a maximum of z equipment on line and its repair channels, which mainly consist of two centers： line replaceable units （LRUs） diagnostic center and shop replaceable units （SRUs） repair center. In these two centers, the resources are finite and different. We introduce routing probabilities to express the repair relationships between resources and failed replaced units. The diagnostic time follows exponential distribution and SRU repair time follows general distribution with known average. We analyze the general model of this system, and present an approximate solution that uses two-step negative binomial approximation to obtain the expected backorders of all LRUs. The first step is fitting negative binomial distributions to the distributions of the number for all SitUs at the repair center, and the second is fitting negative binomial distributions to the convolutions of the distributions of the number for all LRUs in diagnostic and assemblydelayed. Thus, we give the approximate value of operational awilability of equipment based on this method. Finally, the results under two policies of routing probabilities are compared by the optimal curves.     

运筹学中网络图绘制教学探讨

目前运筹学教材中,普遍存在忽视网络图绘制方法的介绍,这给初学者造成一定的学习困难.本文结合作者的教学实践,介绍一种比较容易掌握的网络图绘制方法.     

从社会主义本质角度论国有企业的经营目标

我国的宏伟目标是要建成社会主义社会,国有企业必须同时追求社会效益和经济效益这两个看似不可兼得的目标。对于目标不同的三大类国有企业,应当分而治之。     

教学质量评估的灰关联分析

用灰关联分析方法对某校教师的教学质量进行评估，得出了教学质量评估指标的分类模式以及最优指标因素，从而为教学质量的评估提供了科学依据