某型发动机燃油控制执行机构仿真与验证试验

某型飞行验证机采用巡航弹用涡喷发动机为动力,由于飞行包线大大扩展,且发动机工作状态增多,需对燃油调控系统进行仿真,研究发动机控制系统特性。基于质量连续与力平衡方程在MSC EASY5仿真平台框架下建立了燃油调节执行机构的动力学模型,进行了开环控制结构下执行机构系统稳态和动态特性仿真,并在半物理动态模拟实验台上进行了验证试验。研究结果表明,调节器执行机构系统满足发动机工况范围技术指标要求,为发动机控制系统改型研制打下了基础;采用的建模与仿真方法用于工程设计是可行的,为发动机燃油控制系统的设计与仿真研究提供了一种便捷的技术手段。     

高温超导体Dy_(1-x)Pr_xB_(a2)Cu_3O_(7-δ)的磁弛豫研究

本文通过磁驰豫实验研究发现，Pr的掺杂对提高高温超导体的磁通钉扎能力有明显的作用．     

优良的网页设计应该注意的几个要素

《网页设计》是现代教育技术专业的一门必修课。笔者根据自己从事网页设计的经验,从网页的内容、设计语言的选择、布局风格、数据库的应用、讨论区的创建以及网络安全等几个方面探讨了网页设计应注意的一些基本要素。     

一种新的人才培养模式——“动态能力集”工学结合人才培养模式研究

“动态能力集”工学结合人才培养模式强调能力是动态的、是一种集合。核心思想是依据行业需求，以就业为导向，以能力为中心，将实际工作岗位所需求的各种能力任务化、项目化，构建人才培养动态能力集。根据任务化了的动态能力集再确定相应的课程体系、动态的能力模块、动态的能力点，并采用工学交替、任务驱动的教学模式，做到真正的知行合一。     

核磁共振弛豫时间和磁场均匀性的研究

本文介绍了核磁共振实验的装置和工作原理,并着重讨论核磁共振实验中两个重要的问题,驰豫时间和磁场的均匀性的估算。     

湖南柘溪水电站混凝土坝的流变断裂学研究(英文)

应用流变断裂学理论,本文着重研究了湖南柘溪水电站单支墩大头坝混凝土裂纹体裂纹发生与发展的计算程序。理论计算结果与现场观测结果基本一致。     

动态优化与方法初探

本文综述了机械动态优化设计的各种方法,考查了这些方法的优缺点及其存在的问题,阐述了改进动态优化方法的途径。     

A modified model for dynamic properties of visual receptive field

The extended Gabor function model for visual receptive field ( RF) was modified by substituting the term related to time with two-order integral kernel of F function to generate a new model called modified Gabor function model of RF. A set of the modified Gabor models (MGM) can present the major spatiotemporal properties of neuronal receplive fields at different levels of primary visual pathway. The transient responses, dynamic properties of RF simulated by MGM, are in good agreement with the observations in electrophysiological experiments.     

Transient reconnection caused by non-homogenous dynamic pressure

It is proposed that local and transient reconnection in the plasma boundary layer can be caused by the impact and switch-off of non-homogenous dynamic pressure. Magnetohydrodynamic simulation is used to investigate the reconnection processes in these two cases. It is found that if the inflow is homogeneous, the reconnection will not take place; if the inflow is a shearing flow, no matter how great the shear of the flow is, the reconnection can be caused either during or after the impacting period. It is pointed out that a sudden stop of external force may be an important triggering mechanism of energy transformation and reconnection in the plasma boundary layer region.     

Optimal purchasing process for electricity and renewable energy credits with price and demand uncertainty

This paper optimizes the electricity and renewable energy credit (REC) purchasing process for energy distribution. Electricity is traded in deregulated time-sequential markets at fluctuating prices. Optimal electricity purchasing under price and demand uncertainty is a challenging task for electricity distributors, and the recently implemented renewable portfolio standards (RPS) further complicate the purchasing process. Government regulatory decisions concerning the RPS require distributors to purchase corresponding certificates, namely RECs, equivalent to a certain percentage of their electricity sales. This paper formulates and optimizes the joint purchasing process for electricity and RECs. It also analyzes the effect of RPS policy on electricity distributors.