Magneto-transport properties of Fe-doped LSMO manganites

Magneto-transport measurements have been performed on La_0.67Sr_0.33Mn_1−xFe_xO₃ (x = 0.0, 0.05 and 0.07) manganites synthesized by solid state route. The overall nature of AC susceptibility is found to be frequency independent. With the substitution of Mn by Fe, the transport properties dramatically change suppressing the double-exchange interaction. This in turn weakens the ferromagnetism and consequently decreases the paramagnetic to ferromagnetic transition temperature (T_c). However, DC electrical resistivity of the samples show board hump at metal-insulator transition temperature (T_MI) in contrary with sharp transition at T_c and T_MI < T_c indicating decoupling of electrical and magnetic properties. Resistivity behavior of these samples can be well explained by the consideration of bond percolation model which is basically developed from effective approximation method.     

A fast flow control algorithm for real-time emergency evacuation in large indoor areas

Evacuation in an emergency is always an important issue for shopping malls, subway stations and other populous indoor places. The purpose of evacuation is to evacuate people from the danger zone through exits within the shortest possible time. To help evacuation missions to be carried out efficiently and effectively by rescuers, a fast evacuation approach is needed.     

基于虚拟样机技术的液压液力复合转向机构的优化匹配研究

满足履带车辆在恶劣路面实现原地转向是转向系统设计的重要指标之一.目前,我国履带车辆普遍采用液压机械双功率流的无级转向系统,为满足大吨位车辆原地转向要求,必须匹配大排量的液压泵-马达或提高液压泵-马达的系统压力.为克服这些不足,提出液压液力复合转向工作机构.首先分析了液压液力复合转向机构的工作原理,确定了液力偶合器的原始特性.然后,以某车的综合传动系统为研究基础,通过引入液力偶合器构成液压液力复合转向机构,并在ADAMS/View环境中建立了相应的虚拟样机模型.以此模型为蓝本,确定了4个设计变量,通过分析,偶合器的有效直径和动力输入到液力偶合器泵轮的传动比为关键变量,并进行变量的敏度分析.最后,建立了优化约束条件和优化目标,利用ADAMS的DOE(Design of Experiment)功能进行了优化设计的仿真分析,确定了偶合器的有效直径和传动比,并进行了仿真实验.仿真表明,设计的液压液力复合转向机构可满足车辆在恶劣路面原地转向的要求,同时显著降低了液压泵-马达的排量,为低排量泵-马达实现大吨位车辆的转向性能提供了依据.     

建筑虚拟空间发展问题探讨

信息网络时代推动了建筑虚拟空间的产生和发展一该文从虚拟空间的定义、类型和发展现状等研究出发,论证了虚拟空间不断发展的必然性,得出建筑空间中虚、实两部分关系的发展趋势,以及两者结合的可行性方式。     

Lighting,colour and geometry: Which has the greatest influence on students' cognitive processes?

Many studies have analysed the effects that design elements, such as lighting and colour, have on students' cognitive functions. These analyses, while providing useful information, do not allow researchers to compare the effects of multiple design elements. The objective of the present study is to analyse the relative influence of lighting, colour and geometry on attention and memory, the main cognitive functions that underlie learning, and on preference. In a controlled, virtual reality (VR)-based experiment, 200 university students (100 male/100 female) performed attention, memory and preference tests in classrooms with different configurations of lighting (colour temperature and illuminance), colour (saturation and hue) and geometry (height and width). The results identified significant gender-based differences, which demonstrates the need to segment, by gender, samples in this type of study. Lighting had the greatest influence, significantly affecting males' memories, females' attention and the preferences of both genders. Colour was also an influential element, significantly affecting females' attention, while geometry was the least influential. Finally, it should be highlighted that attention was the metric most sensitive to design variations. These results may be of interest to architects, interior designers and engineers who wish to create classrooms that satisfy students’ psychological needs.     

虚拟界面的定义与描述

虚拟界面是建筑空间形式系统的一部分,是对该系统的补充,本文在完善空间界面分类的基础上,对虚拟界面作了定义,并通过阐明虚拟界面3种基本类型,详细描述了各种虚拟界面的构成特征,最后以此对密斯的巴塞罗那德国馆进行分析,验证了虚拟界面概念对解读空间的有效性。     

基于BIM的虚拟设计技术在北京坊项目中的实践

本文运用建筑信息模型BIM(Building Information Modeling),研究了虚拟设计、虚拟施工以及基于虚拟模型的算量技术,通过探讨BIM相对于二维CAD图纸的优势,阐明了BIM虚拟设计技术对建筑工程行业的革命性作用,采用BIM协同设计技术,提升了各专业人员间的协同、节省了建筑成本,并将其运用于大栅栏北京坊大型工程项目实例,展现了虚拟设计、虚拟施工及项目管理过程,以改善设计质量和建筑性能,优化和完善设计方案。     

建筑日照计算中遮挡影响范围的合理界定

随着国内城市建设快速发展, 高层、超高层建筑不断出现, 由于建筑物遮挡造成的采光权纠纷问题越发严重。在规划管理中如何合理地界定日照影响遮挡范围, 平衡开发单位和周边住户的利益关系, 是摆在各级规划管理部门的难点问题。本文结合国内国家和地方日照相关标准, 并从各地开展的实际工作情况出发, 对建筑日照计算中如何界定合理的计算影响范围进行了讨论, 对各级规划管理部门合理界定日照遮挡影响范围具有一定参考意义。     

VR技术在生活区火灾逃生中的应用

施工生活区是建筑施工人员临时活动和休息的区域,由于施工现场工人较多,导致生活区人员密集,来源复杂,流动性大,存在较多的安全隐患,发生火灾时,带来的危害不可估量,因此施工生活区的火灾安全管理成为了施工企业安全文明施工的重点。本文通过三维模型结合虚拟现实技术,设计了生活区虚拟现实火灾逃生场景,让施工人员亲身体验生活区发生火灾时应急逃生的技能和方法,提高施工人员的安全意识,避免火灾的发生。     

基于虚拟地理信息系统技术的城市道路路线设计研究

通过虚拟现实和地理信息系统在城市道路路线设计中应用的研究,论述该系统的功能及其在城市道路路线平、纵、横道路路线设计的应用,说明该系统是计算机在城市道路设计上应用的一个飞跃。