校园开放空间POE研究——以北京大学静园为例

使用状况评价（POE）是系统描述和评价建成环境的实证性研究方法。它主要关注空间、环境的使用效能和利用方式，并为规划设计项目提供科学依据。在校园建设过程中，POE研究可以被视为灵活、交互式的反馈过程，它使得未来的校园环境设计能够更好地满足使用者需求。以北京大学静园区域户外开放空间为例，从动态交通、公共空间中的行为活动规律两方面对场地进行系统的POE分析，并在此基础上提出改造策略与建议，为“以人为本”的校园开放空间设计提供依据。     

地震灾害挑战我国农村土地政策

此次汶川地震造成大量农田毁损,同时山体滑坡、泥石流等次生灾害造成大量土地无法继续利用,城乡"失地"现象严重.灾区土地利用面临着方方面面的调整.自然灾害造成的重大人地关系改变也给我国现行的农村土地政策提出了挑战.通过对灾区震后土地利用变化和灾后重建面临的土地利用调整的分析,反思了我国目前的耕地保护、集体建设用地流转和规划管理等政策,并针对灾区需求,提出相应的政策建议.     

新农村建设规划与城市扩张的景观安全格局途径——以马岗村为例

强调中国大地上广大传统村落是保障国土生态安全、维持人地关系和谐,以及保障中华民族草根信仰持续稳定的细胞,也是和谐社会的基础.如何保护好村落的生态环境、传承历史文化、维护草根信仰体系,建立一个充满活力的和谐社会将是新农村建设规划的出发点和归宿.笔者应用景观安全格局的理论和方法,以广东省顺德市的马岗村为例,把村落看作是大地生命系统的有机组成部分,通过判别和完善对村落的生态、历史文化、社会结构和信仰体系具有关键意义的景观元素、局部和空间关系,建立景观安全格局,来保障村落的生态、历史和社会文化之生命在快速的城镇化和社会主义新农村建设中得以延续.     

Synthesis and performance of novel magnetically separable nanospheres of titanium dioxide photocatalyst with egg-like structure

A magnetically separable photocatalyst TiO(2)/SiO(2)/NiFe(2)O(4) (TSN) nanosphere with egg-like structure was prepared by a unique process that combined a liquid catalytic phase transformation method, reverse micelle technique and chemical precipitation means. The prepared photocatalyst shows high photocatalytic activity for the degradation of methyl orange in water. The magnetic property measurements indicate that the photocatalyst possesses a superparamagnetic nature. It can be separated from water when an external magnetic field is added and redispersed into water solution after the external magnetic field is eliminated. It is one of the promising photocatalysts for wastewater treatment. A transmission electron microscope (TEM) and an x-ray diffractometer (XRD) were used to characterize the structure of the TSN photocatalyst. The results indicate that nickel ferrite core nanoparticles were completely encapsulated into monodisperse silica nanospheres as carrier, and titania nanoparticle aggregates were coated onto the surface of SN nanospheres, forming an imperfect TiO(2) shell for photocatalysis. The SiO(2) layer between the NiFe(2)O(4) core and the TiO(2) shell effectively prevents the injection of charges from TiO(2) particles to NiFe(2)O(4), which gives rise to an increase in photocatalytic activity. Moreover, the recycled TSN exhibits good repeatability of the photocatalytic activity.     

An improved numerical method for predicting intermetallic layer thickness developed during the formation of solder joints on Cu substrates

An improved numerical method has been developed for calculating the thickness of intermetallic layers formed between Cu substrates and solders during the soldering process. The improved method takes into account intermetallic dissolution during heating and intermetallic precipitation during cooling and requires as input (1) the temperature-time profile for the soldering process, (2) the experimentally determined isothermal growth parameters for the growth of the intermetallic layer into Cu saturated molten solder, (3) the experimentally determined Nernst-Brunner parameters for the dissolution of Cu into molten solder, (4) the experimentally determined solubility of Cu in molten solder and (5) assumptions about the thickness of the boundary layer in the liquid ahead of the growing intermetallic. Calculations show that the improved method predicts intermetallic growth between Cu substrates and 96.5Sn-3.5Ag solder during reflow soldering better than a previously developed method, which did not take into account dissolution during heating and precipitation during cooling. Calculations further show that dissolution has a significant effect on growth, while precipitation does not.     

无功就地补偿在晋城市自来水公司的应用

0前言电费在供水企业的生产成本中占相当大的比重。各地都有着各自不同的生产条件,除合理选择机泵型号外,积极响应国家的电价政策,提高功率因数,降低电费开支显得尤为重要。用户用电功率因数的高低,对电力系统发、供、     

Effect of HEA/Al composite interlayer on microstructure and mechanical property of Ti/Mg bimetal composite by solid-liquid compound casting

In this study,HEA/AI composite interlayer was used to fabricate Ti/Mg bimetal composites by solidliquid compound casting process.The Al layer was prepared on the surface of TC4 alloy by hot dipping,and the FeCoNiCr HEA layer was prepared by magnetron sputtering onto the Al layer.The influence of the HEA layer thickness and pouring temperature on interface evolution was investigated based on SEM observation and thermodynamic analysis.Results indicate that the sluggish diffusion effect of HEA can ...     

阻尼多楔带传动系统建模及带滑移控制分析

考虑多楔带的阻尼特性和带在带轮上的蠕变对带张力的影响,建立了阻尼多楔带传动系统旋转运动模型,给出了带张力和各带轮的旋转角位移的数值计算方法,并引入了滑移因子预测滑移现象的发生.分析研究多楔带阻尼对系统运动特性的影响,及当多楔带传动系统结构参数确定时,张紧器预载荷、安装角对带滑移的影响.建立的阻尼多楔带传动系统旋转运动模型和数值求解方法为带传动系统的研究提供了理论依据,对带滑移控制的分析为带传动系统的设计提供了参考.