Comparison of the RF MEMS switches with dielectric layers on the bridge’s lower surface and on the transmission line

Previously, we proposed that the dielectric layer of RF MEMS switch can be fabricated either on the transmission line, as traditional switches, or on the lower surface of the bridge. This paper presents a detailed comparison of the RF MEMS switches with different positions of dielectric layer. Through theoretically analyzing the physical model of fringing capacitance, it is revealed that different positions of dielectric layer can result in different switch capacitances. Therefore, the change of d...     

Characteristics of on-chip dipole antenna using diamond for intra-chip wireless interconnect

In this paper,a 2-mm long on-chip dipole antenna pair on silicon substrate is simulated to investigate the transmission characteristics.A novel technique is proposed by employing a 0.35-mm thick diamond layer between silicon substrate and heat sink to improve antenna performance.The simulated transmission gain of this antenna pair with 1 mm separation on a 10-Ω cm silicon substrate increases by 9 dB at 20 GHz.A modified plane wave model involving diamond layer is also presented to explain gain improvement.E...     

温度对球墨铸铁QTRSi4Mo1拉伸性能与循环变形的影响

开展了球墨铸铁QTRSi4Mo1室温到760℃条件下的静载拉伸试验和应变控制低周疲劳试验研究.通过比较不同温度下材料拉伸性能与循环应力应变响应特性,表明球墨铸铁QTRSi4Mo1在300℃～400℃附近存在一定脆性,在500℃以上具有较好的塑性变形能力;在中温(400℃～500℃)条件下材料循环应力应变行为表现为循环硬化,在高温(760℃)条件下表现为循环软化,而在较低温度下则表现出更复杂的应力应变演化,同时利用Ramberg-Osgood方程可准确描述其循环应力应变特性;在较低温度下材料具有non-Masing特性,而在500℃以上则具有Masing特性.     

中国移动北京生产中心概念性建设方案

新的中国移动总部坐落于北京东部一个平坦而空旷的场地之上．离主干道不到1000m。在通过中央大门进入密封的建筑区域之前是一大片的空旷的广场。     

Study on the properties of conductive adhesives in various curing manners for MCM applications

In this work, the properties of solvent and solvent-free electrically conductive adhesives (ECAs) in four curing manners and after solder reflows are investigated for multi-chip module applications. The curing behaviors and thermal degradation of solvent and solvent-free ECAs are also studied by differential scanning calorimeter and thermogravimetric analysis, respectively. The bulk resistivity of ECAs in four curing manners is significantly different, even if they are cured at the same temperature and time. The conductive trends of solvent and solvent-free ECAs are also different. The good and poor conductive properties of solvent ECA are obtained at curing temperature starting from room temperature and setting temperature, respectively. However, the results of solvent-free ECA are opposite. All the bulk resistivity and the coefficients of thermal expansion of solvent and solvent-free ECAs tend to decrease after solder reflows. The reasons are studied by thermomechanical analyzer, thermogravimetric analysis, topography and deformation measurement, and scanning electron microscopy.     

催化裂化装置腐蚀失效分析与实验室模拟实验研究

通过对催化裂化再生器在NOx-SOx-H2O环境下现场构件的无损检测、硬度测定、化学成分分析、介质分析、金相检验、断口分析及腐蚀产物分析等表明，催化裂化再生系统由于设备壁温长期处于烟气露点温度．在NOx-SOx-H2O烟气结露形成的酸性腐蚀介质和残余应力的共同作用下，发生硝酸盐应力腐蚀开裂。实验室进行的现场模拟实验所得的结果与催化裂化再生器现场失效构件的实验结果具有共同的特征，进一步论证了现场装置的开裂是由硝酸盐应力腐蚀开裂引起的。力图对再生器设备在NOx-SOx-H2O烟气体系中产生的应力腐蚀开裂进行预测，并为进一步研究有效的防护对策提供科学的依据。     

High performance word level sequential and parallel coding methods and architectures for bit plane coding

This paper introduced a novel high performance algorithm and VLSI architectures for achieving bit plane coding （BPC） in word level sequential and parallel mode. The proposed BPC algorithm adopts the techniques of coding pass prediction and parallel ＆ pipeline to reduce the number of accessing memory and to increase the ability of concurrently processing of the system, where all the coefficient bits of a code block could be coded by only one scan. A new parallel bit plane architecture （PA） was proposed to achieve word-level sequential coding. Moreover, an efficient high-speed architecture （HA） was presented to achieve multi-word parallel coding. Compared to the state of the art, the proposed PA could reduce the hardware cost more efficiently, though the throughput retains one coefficient coded per clock. While the proposed HA could perform coding for 4 coefficients belonging to a stripe column at one intra-clock cycle, so that coding for an NxN code-block could be completed in approximate N2/4 intra-clock cycles. Theoretical analysis and experimental results demonstrate that the proposed designs have high throughput rate with good performance in terms of speedup to cost, which can be good alternatives for low power applications.     

Formation control and collision avoidance for multi-UAV systems based on Voronoi partition

This paper deals with the formation control problem of multiple unmanned aerial vehicles(UAVs) with collision avoidance. A distributed formation control and collision avoidance method is proposed based on Voronoi partition and conventional artificial potential field. The collision avoidance is achieved by partitioning the whole space into non-overlapping regions based on Voronoi partition theory, which is taken as the task region to confine the movement of each UAV. The general motion control law is designed based on the conventional artificial potential field. As this often leads to local optimum when two UAVs are going to collide with each other and they may stay still where the repulsive force is adversely equivalent to the attractive force. To address this problem,the destination switch scheme is further proposed to let UAVs switch destinations when they reach the local equilibrium. Finally,the effectiveness of proposed formation control algorithm is validated by simulations and experiments.     

铜套的选配计算与应用

文中介绍了铜套选配计算的经验公式及列表法在铜套装配计算中的应用,并且能为铜套尺寸的设计提供参考.