Recovery of gold cyanide using inherently conducting polymers

Removal of gold from basic solutions containing [Au(CN)₂]^? has been demonstrated using the inherently conducting polymer polypyrrole. Polymers containing sulfonated aromatic dopants have been found to display a significant ability to remove gold from such solutions. Experiments performed in solutions containing both gold and copper cyanide complexes indicate that the recovery process is not highly selective. However, the polypyrroles used display significantly faster rates of gold recovery than activated carbon. © 2003 Society of Chemical Industry     

Highly compact AC-AC converter achieving a high voltage transferratio

This paper reports a new, highly integrated modular design approach for pulsewidth-modulation AC-AC converters based on a modular phase-bank structure. Novel high-power 3-in-1 integrated bi-directional power modules (IBPM) rated at 1200-V AC and 150 A and the 3-to-1 phase bank circuits have been successfully developed, fabricated and tested. This enables the modularity design of the multiphase converter systems and reduces the critical parasitic inductance. A theoretical analysis of the IBPM's silicon utilization for this new breed of direct power converters has been outlined. A lab prototype at medium power level has been successfully designed, implemented, and tested with good results. A nearly 460-VRMS out voltage at a 1:0.955 voltage transfer ratio, which, perhaps, is the highest performance reported so far in the literature, has been achieved by the novel two-side modulation control system. The converter-fed AC motor system is able to operate over the 0-240 Hz range with inherent regenerative capability and four-quadrant operation. Potential industrial applications are also briefly highlighted in this paper     

Fine-line conductor manufacturing using drop-on demand PZT printingtechnology

An emerging selective metallization process to fabricate fine-line conductors based on drop-on-demand (DOD) ink jet printing and novel nano-particle fluid suspensions (NPFS) was studied. The suspensions consist of 1-10 nm silver or gold particulates that are homogeneously suspended in an organic carrier. A piezo-electric droplet generator driven by a bipolar voltage signal is used to dispense 50-70 μm diameter droplets traveling at 1-3 m/s before impacting a compliant polyimide substrate. The deposit/substrate composite is subsequently processed at 300°C for 15 min to allow for complete evaporation of the carrier and for sintering of the nano-particles, thereby yielding a finished circuit interconnect. Test vehicles created using this technique exhibit features as fine as 120 μm wide and 1 μm thick with resistivities on the order of 3.5×10^-5 Ωcm. The circuitry performed well under environmental conditioning. As expected, repeatability of circuitry fabrication showed sensitivity to the generation of steady, satellite-free droplets. In an effort to generate droplets consistently, it is essential to develop a strong fundamental understanding of the correlation between device excitation parameters and dispensed fluid properties, and to resolve the microrheological behavior of the NPFS when flowing through the droplet generator     

Internet网络延时分析

本文对Internet网络延迟进行了较为全面的分析，介绍了几种减少网络延迟的技术。然后提出一种新的方法，并用排队论加以分析。     

Apply geometric duality to energy-efficient non-local phenomenon awareness using sensor networks

A powerful concept to cope with resource limitations and information redundancy in wireless sensor networks is the use of collaboration groups to distill information within the network and suppress unnecessary activities. When the phenomena to be monitored have large geographical extents, it is not obvious how to define these collaboration groups. This article presents the application of geometric duality to form such groups for sensor selection and non-local phenomena tracking. Using a dual-space transformation, which maps a non-local phenomenon (e.g., the edge of a half-plane shadow) to a single point in the dual space and maps locations of distributed sensor nodes to a set of lines that partitions the dual space, one can turn off the majority of the sensors to achieve resource preservation without losing detection and tracking accuracy. Since the group so defined may consist of nodes that are far away in physical space, we propose a hierarchical architecture that uses a small number of computationally powerful nodes and a massive number of power constrained motes. By taking advantage of the continuity of physical phenomena and the duality principle, we can greatly reduce the power consumption in non-local phenomena tracking and extend the lifetime of the network.     

完善管理机制提高校长队伍整体水平

校长是一所学校的指挥者,一名好的校长,可以带出一批训练有素的教师队伍,可以推进学校教育改革的不断发展.抓好校长队伍建设是贯彻党的教育方针,全面推进素质教育,办好学校的头等大事.那么,如何加强校长队伍建设就显得尤为重要了.     

东丽湖邻里中心

在承接这个项目之前，我们不知道天津东部还有东丽湖这么一大片保存完好的湿地，夕阳映照着辽阔的水面，芦苇中闪现着轻盈的水鸟。邻里中心——作为这片宝地旁边200hm^2大型低密度社区第一个登台亮相的小组团，对参与其中的所有人来说，既有动人的诱惑，又有切实的压力。     

磷酸异戊酯萃取U,Np,Pu性能的研究

测定磷酸异戊酯（ＴｉＡＰ）对Ｕ（Ⅵ）、Ｎｐ（Ⅳ）、Ｎｐ（Ⅴ）、Ｎｐ（Ⅵ）、Ｐｕ（Ⅳ）和Ｐｕ（Ⅲ）的萃取性能及对Ｔｈ（代替Ｐｕ）的萃取容量。研究了二乙三胺五乙酸（ＤＴＰＡ）络合剂对上述核素形成配合物的条件。结果表明，在用ＴＢＰ和ＴｉＡＰ作萃取剂时，可用ＤＴＰＡ络合Ｎｐ（Ⅵ）、Ｐｕ（Ⅲ）．从而改善乏燃料后处理中Ｕ产品对Ｎｐ、Ｐｕ和Ｐｕ产品对Ｎｐ的去污。     

Stochastic TCP friendliness: Expanding the design space of TCP-friendly traffic control protocols

While the current definition of TCP friendliness has enabled a wide variety of traffic control protocols other than TCP, it still considerably restricts the design space of TCP-friendly traffic control protocols. For example, some multimedia streaming applications prefer a smooth sending rate on a time scale of tens of seconds, however, a UDP flow maintaining such a long smoothness time scale is naturally not TCP friendly by the current definition. In this paper, we propose an innovative method to relatively compare the degrees of TCP friendliness of different traffic control protocols, and use it to define a new class of TCP friendliness definitions, called stochastic TCP friendliness (STF). STF greatly expands the design space of TCP-friendly traffic control protocols, while still effectively maintaining the desired fairness of the Internet. To demonstrate the expanded design space, we also develop a new congestion control protocol, called TCP-friendly CBR-Like Rate Control (TFCBR), for multimedia streaming applications which do not require a high sending rate but prefer a smooth sending rate on a time scale of tens of seconds. TFCBR is stochastically TCP friendly, however, it is not TCP friendly by the current definition.