Phase change memory

Phase change memory (PCM) is a non-volatile solid-state memory technology based on the large resistivity contrast between the amorphous and crystalline states in phase change materials. We present the physics behind this large resistivity contrast and describe how it is being exploited to create high density PCM. We address the challenges facing this technology, including the design of PCM cells, fabrication, device variability, thermal cross-talk and write disturb. We discuss the scalability, assess the pe...     

海绵城市理念在校园风景园林规划设计中的应用——以天津大学北洋园校区为例

当前中国面临着城市内涝、水资源短缺等一系列水问题,海绵城市理念的应用正是解决这些问题的有效途径。通过分析海绵城市的建设理念及实践,并以天津大学北洋园校区为例,结合国内外雨洪管理的理念、技术和方法,构建了以分区而治、内外联合为主的"弹性"雨洪管理系统。将校园划分为3个子排水分区,阐明"海绵城市"的理念。校园设计提出了保护场地原有的生态系统,利用生态修复来减缓施工造成的损害,并在设计和施工中使用低影响开发(LID)实践等设计目标,以期指导我国海绵试点城市的建设。     

“山水楼”模式：基于艺文分析的昆明 西山-滇池-大观楼传统公共园林景观 偏好研究

中国传统公共园林由士绅官员、文人墨客、地方民 众等历经千百年共同建构、感知，承载着中华民族集体的景 观偏好。以西南边疆云南省省会昆明的西山-滇池-大观楼传 统公共园林为例，整理描写其景观特征的330篇古代艺文， 通过Nvivo软件，运用扎根理论从五感角度分析艺文内容， 并对艺文景观偏好进行三级编码。研究发现：1)视觉景观 在艺文中出现的占比最高，听觉、触觉、嗅觉次之，分别为 99%、36%、24%、7%，视觉和听觉同时出现的艺文占比 高达35%；2)“山水楼”是中国传统公共园林重要的景观偏 好模式，蕴含了中国传统公共园林营造智慧和中国人集体景 观审美意识。昆明“山水楼”模式的出现，是中华民族在西 南边陲地区“一带一路”文化传播的见证。     

NMR法研究羧甲基羟丙基纤维素的取代结构

羧甲基羟两基纤维素(CMHPC)经水解和乙酰化反应后,利用~1H NMR和~(13)C NMR谱确定其取代度和取代基分布,提出了纤维素葡萄糖单元上羟基的相对反应活性顺序。     

基于ZigBee技术的无线数据采集系统设计

提出了一种新型的基于ZigBee技术的无线数据采集系统,详细介绍了其系统结构和各个子模块的硬件电路设计及软件流程设计.系统以自带Zigbee/IEEE802.15.4协议的JN5121-M0006模块为核心.以AT45DB081A作为外部存储器,利用FYD12864-0402B输出图形文字信息,同时还采用了SPCE061A芯片来处理语音数据,其目的在于克服有线网络的局限性,并避免其他无线通信技术高功耗的缺点.     

Titanium Aluminides: Science, Technology, Applications and Synthesis by Mechanical Alloying

The production. characteristics. and commercialization of monolithic and composite titanium aluminides are summanzed with emphasis on use in the demanding aerospace industry. The attractive elevated temperature properties combined with alow density make these materials of great interest, but inherently low "forgiveness", and environmental concerns, must be overcome before widespread use will occur One synthesis method for the production of monolithic titanium aluminides-mechanical alloying- will be discussed in detail     

液压锤液压系统的建模与仿真

研制和开发了液压锤插装阀集成液压系统；介绍了液压系统“灰箱”建模理论与方法；应用“灰箱”建模法和自动建模与仿真软件，对液压锤液压系统动态特性进行了建模与仿真研究。实践表明：液压锤新型插装阀集成液压系统具有许多优点和良好的动态特性；该“灰箱”建模理论与方法可广泛应用于液压系统动态分析与设计。     

香港“快速原型、快速模具及产品开发技术研讨会”选刊之三 实施并行工程的有效工具和策略

阐明了并行工程的概念,分析了并行工程成为当前应用中最广泛接受的工程手段之一的原因,叙述了实行并行工程所涉及的问题,最后列举了两个从采用并行工程中取得很大效益的国外公司的实例。     

Effect of atmospheric aerosol on surface ozone variation over the Pearl River Delta region

Our analysis of the surface aerosol and ultraviolet(UV) measurements in Pearl River Delta(PRD) region shows that the sur-face UV radiation is reduced by more than 50% due to high aerosol concentrations.This has important impacts on urban eco-system and photochemistry,especially on ozone photochemical production over the region.The quantitative effect of aerosols on surface ozone is evaluated by analyzing surface observations(including ozone,ultraviolet radiation,aerosol radiative pa-rameters) and by using r...     

Time-stepping finite element analysis on the influence of skewed rotors and different skew angles on the losses of squirrel cage asynchronous motors

To study the influence of skewed rotors and different skew angles on the losses of squirrel cage asynchronous motors,a 5.5-kW motor was taken as an example and the multi-sliced field-circuit coupled time stepping finite element method(T-S FEM)was used to analyze the axially non-uniform fundamental and harmonic field distribution characteristics at typical locations in the stator and rotor cores.The major conclusions are:firstly the skewed rotor exhibits a decrease in the harmonic copper losses caused by slo...