蜕变——中国气象局华风影视大楼

华风气象影视大楼总面积4万平方米，根据空间功能不同分为办公大楼和商务写字楼两部分，办公大楼是集演播室、制作机房、办公室为一体的九层综合性建筑。设计师杨宇在刚接触到这个项目的时候，面对的是一个既成事实的建筑。     

Silk materials for medical,electronic and optical applications

Silk derived from the silkworm Bombyx mori is among the most important fibrous protein biomaterials due to large-scale production from natural sources, excellent biocompatibility, unique mechanical properties and controllable degradation. Silk fibroin can be processed into a variety of formats to match different applications, such as tissue engineering, drug delivery or as the passive substrate of a bio-device. Advances in fabrication technologies provide new possibilities for the combination of silk fibroin with other nanomaterials to functionalize silk fibroin for specialized purposes, including sensing, cell visualization,resistance to ultraviolet light and provision of antibacterial properties. As the requirement for wearable and intelligent devices has become increasingly important over recent years, silk fibroin has been utilized as the active element in electronic and optical instruments. This review summarizes these recent advances in the innovative applications of silk fibroin.     

分布式风光储系统双向DC-DC变换器研究

文中提出了一种分布式风光储系统的架构,并重点研究系统中连接蓄电池和直流母线的双向DC-DC变换器。双向DC-DC变换器能够实现太阳能阵列、风机、电网和蓄电池之间的能量交换、调节母线电压,是风光储系统的关键部分。本文采用高变比的双有源全桥变换器构成双向DC-DC变换器,它既能连接较低输出电压的蓄电池和高压直流母线,又能通过移相控制实现功率双向流动和软开关。本文研制了一台3 k W风光储系统样机,在不同工况下测试了双向双有源DC-DC变换器的功能。     

本色生活

如果认为城市也是一座围城，那么那句老话“外面的想进来，里面的想出去”，套用其上也是妥贴的，可如今，对于城市，毕竟是进来的多了，出去的少，特别是想出去的一部分，多数仅停留在自我安慰阶段，真正付诸实施的，屈指可数。     

Three-dimensional porous electrodes for direct formate fuel cells

The dual-layer electrode for fuel cells is typically prepared by binding discrete catalyst nanoparticles onto a diffusion layer. Such a random packing forms a dense catalyst layer and thus creates a barrier for mass/ion transport, particularly for direct liquid fuel cells. Three-dimensional porous electrodes, a thin nano-porous catalyst layer uniformly distributed on the matrix surface of a foam-like structure, are typically employed to improve the mass/ion transport. Such a three-dimensional porous structure brings two critical advantages:(i) reduced mass/ion transport resistance for the delivery of the reactants via shortening the transport distance and(ii) enlarged electrochemical surface area, via reducing the dead pores, isolated particles and severe aggregations,for interfacial reactions. Moreover, the three-dimensional design is capable of fabricating binder-free electrodes, thereby eliminating the use of ionomers/binders and simplifying the fabrication process. In this work, three types of three-dimensional porous electrode are fabricated, via different preparation methods, for direct formate fuel cells:(i) Pd/C nanoparticles coating on the nickel foam matrix surface(Pd-C/NF) via a dip-coating method,(ii) Pd nanoparticles depositing on the nickel foam matrix surface(Pd/NF) via reduction reaction deposition, and(iii) Pd nanoparticles embedding in the nickel foam matrix(Pd/(in)NF)via replacement reaction deposition. The latter two are binder-free three-dimensional porous electrodes. As a comparison, a conventional dual-layer design, Pd/C nanoparticles painting on the nickel foam layer(Pd-C//NF), is also prepared via direct painting method. It is shown that the use of the three-dimensional Pd-C/NF electrode as the anode in a direct formate fuel cell results in a peak power density of 45.0 mW cm~(-2) at 60°C, which is two times of that achieved by using a conventional dual-layer design(19.5 mW cm~(-2)). This performance improvement is mainly attributed to the unique three-dimensional structure design,which effectively enhances the mass/ion transport through the porous electrode and enlarges the electrochemical surface area(accessible active area) for interfacial reactions. In addition, the delivery of the fuel solution is still sufficient even when the flow rate is as low as 2.0 mL min~(-1). It is also demonstrated that direct formate fuel cells using two binder-free electrodes yield the peak power densities of 13.5 mW cm~(-2)(Pd/(in)NF) and 14.0 mW cm~(-2)(Pd/NF) at 60°C, respectively, both of which are much lower than the power density achieved by using the Pd-C/NF electrode. This is because the electrochemical surface areas of two binderfree electrodes are much smaller than the Pd/C-based electrodes, since the specific area of Pd/C nanoparticles is much larger.     

山水奢侈——北京菩提谷山庄

王善祥以当代建筑手段塑造了传统山水画中的“山居”意境。     

基于GPRS网络的新型环网柜终端

由于在配电系统的环形供电网络中供电线路分散性大,使得电缆、光缆的有线通讯方式投资大、可靠性低,该文提出并研制了基于GPRS(通用分组无线业务)网络的新型环网柜终端,该终端以DSP为核心,对配电环网中的电压、电流、三相总的有功电量、无功电量以及环网柜电缆出线故障进行监测,是集环网柜终端、电能表、无功补偿装置为一体的新型设备。通过GPRS网络为信道传输数据,实时性好、可靠性高、投资小。     

Role of viscous heating in entransy analyses of convective heat transfer

Science China Technological Sciences - The entransy theory is widely used and found to be effective in thermal analyses and optimizations. Some researchers considered the entransy variation due to...     

遥感地面站自动化测试系统的设计与应用

遥感卫星地面站的G/T值(品质因数)和系统误码特性是遥感卫星地面站最重要的系统指标,是测试遥感卫星地面站不可或缺的测试项目;传统的测试方法采用人工干预进行测试,测试过程复杂繁琐,人机交互工作量极大,测试效率低下;文中提出了一种在遥感地面站监控管理分系统的统一调度下,协调站内天伺馈分系统、信道分系统和测试分系统的资源,优化测试流程,自动完成系统G/T值和系统误码特性的测试方案,显著提高测试效率;介绍了自动化测试系统的测试原理和自动化测试的设计方法,然后结合某工程实际应用进行了自动化测试,并给出了测试结果;测试结果表明,自动化测试系统的测试结果和人工测试结果一致,但减少了大量的人机交互工作,使测试效率大大提高,测试过程不再繁琐和耗时。     

葡萄糖加氢制山梨醇骨架镍催化剂活化条件的研究

本文对葡萄糖加氢制山梨醇用Raney骨架镍催化剂的活化条件进行了研究,催化剂的加氢活性用丙酮法测定,主要考察了活化时碱NaOH的用量,活化温度及活化时间对Raney骨架镍催化剂加氢活性的影响.试验结果表明,制备Raney骨架镍催化剂较好的活化条件为：NaOH/Al的摩尔比是4.5,活化温度是50℃,活化时间为1.5 h.制得催化剂的催化活性数据丙酮吸氢速率（mL/min,0.2 mL）为7.88,远超过国内山梨醇的行业标准6.00.试验对比表明制得催化剂的催化活性优于同类进口山梨醇骨架镍催化剂.