Design considerations for minimal-power wireless spread spectrumcircuits and systems

Wireless local area networks (WLANs) provide untethered access to digital data in both home and office environments. To preserve mobility for extended periods of time, low power design is a critical enabler. Low-power WLAN design requires consideration at every level from the system topology, protocol, and radio architecture to the detailed circuit design. Every level is required to work together in harmony to gain the maximum in power reduction. This paper discusses the performance requirements and design tradeoffs encountered in the design of minimal-power WLAN systems     

In vitro maintenance of Schistosoma japonicum and surgical transfer from donor to na?ve recipient pigs

The insulin receptor (IR) is a membrane-bound glycoprotein composed of alpha and beta subunits derived from a common precursor. This processing is observed for both subtypes A and B of the IR and its physiological importance is poorly understood. In order to investigate the functional consequences of the absence of IR precursor cleavage, using site-directed mutagenesis of the hIRB cDNA, we have produced two mutants replacing the sequence Arg-Lys-Arg-Arg by either His-Lys-His-Arg or Arg-Lys-Arg-Ser. These two mutants, stably expressed in CHO, were structurally and functionally characterized in comparison to the wild-type human IR. These mutations result in the production of uncleaved receptors which are expressed normally at the cell surface. These receptors bind insulin with a normal affinity and activate the tyrosine-kinase resulting in normal phosphorylation of the receptors. These uncleaved receptors can mediate both the metabolic and mitogenic effects of insulin. These results provide evidence for a fully functional uncleaved insulin receptor of the B subtype (exon 11 + ) in contrast to the uncleaved A subtype (exon 11 -) described in the literature, which shows a reduced affinity for insulin and cannot therefore correctly transduce the insulin signal.     

Implications of on-site distributed generation for commercial/industrial facilities

Next-generation distributed generation (DG) is poised to become a key element in our energy future. Recognizing the increased need for a higher reliability energy system and a cleaner environment, This work presents a technique that helps to identify the impact of grid-connected DG on the reliability of on-site electric power. This analysis shows the optimal DG mix at various facility outage costs with and without an emission restriction. The impact of varying the grid reliability and the capital costs of DG units on the decision to invest in backup power is discussed. The break-even costs of microturbines are also estimated at various facility outage costs and microturbine forced outage levels.     

Estimating the number of different selection decisions resulting from the use of alternate predictor composites.

A method was described whereby d, the number of different selection decisions resulting from the use of alternate predictor composites may be rapidly estimated from the proportion of applicants accepted and the correlation between the composites. It was further demonstrated that the correlation between 2 optimally weighted composites based upon m and n variables (m n) is equal to the ratio of the 2 multiple correlations. 2 examples were used to illustrate the use of d in evaluating selection strategies. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

防止硫磺储罐的腐蚀

现场安装的硫磺储罐通常用于大量熔融硫磺的临时储存。然而由于腐蚀原因,特别是在正常液位上方的气相腐蚀,储罐的使用寿命十分有限。储罐腐蚀可能有若干机理,最可能的是因为在冷金属表面固体硫磺的沉积和痕量液态水的形成。这两种现象共同导致硫化铁的形成。硫化铁是自燃性物质,除了会造成储罐损坏外,如果突然与氧气接触还可能点燃罐内硫磺。抑制腐蚀的最佳方法是防止固体硫磺在罐壁和罐顶处形成。常规的加热技术,例如内部盘管,能有效地保持硫磺于熔融状态,却不能使蒸气相及罐壁维持足够高的温度。通过采用外部分布式加热系统,可将罐壁、罐顶以及蒸气相温度维持在硫磺凝固点之上,从而消除主要的腐蚀途径。论述潜在的腐蚀机理和操作数据,说明工程加热系统的重要性。     

日晒牢度测试: 有助于显现真实色彩

描述了纺织品日晒牢度测试的方法和仪器。详细分析了一种作为最新测试仪实例之一的名为Apollo的仪器,它是由James H.Heal公司开发的。Apollo的最大优点是使用和维护十分简便。     

Electromagnetic energy transport in nanoparticle chains via dark plasmon modes

Using light to exchange information offers large bandwidths and high speeds, but the miniaturization of optical components is limited by diffraction. Converting light into electron waves in metals allows one to overcome this problem. However, metals are lossy at optical frequencies and large-area fabrication of nanometer-sized structures by conventional top-down methods can be cost-prohibitive. We show electromagnetic energy transport with gold nanoparticles that were assembled into close-packed linear chains. The small interparticle distances enabled strong electromagnetic coupling causing the formation of low-loss subradiant plasmons, which facilitated energy propagation over many micrometers. Electrodynamic calculations confirmed the dark nature of the propagating mode and showed that disorder in the nanoparticle arrangement enhances energy transport, demonstrating the viability of using bottom-up nanoparticle assemblies for ultracompact opto-electronic devices.     

Advanced Magnetic Metrology Instrumentation

1. Advancements in Vibrating Sample Magnetometers (VSMs)The VSM is the basic instrument for characterizing magnetic materials as a function of magneticfield and temperature. Its simplicity, versatility andspeed have made it the instrument of choice for bothlaboratory and production environments, ever sinceits invention some forty years ago. Recent advancements in magnetic materials, particularly for the datastorage industry, have imposed new demands on theperformance of VSM systems. They …     

Spontaneous facial expressions of emotion of congenitally and noncongenitally blind individuals.

The study of the spontaneous expressions of blind individuals offers a unique opportunity to understand basic processes concerning the emergence and source of facial expressions of emotion. In this study, the authors compared the expressions of congenitally and noncongenitally blind athletes in the 2004 Paralympic Games with each other and with those produced by sighted athletes in the 2004 Olympic Games. The authors also examined how expressions change from 1 context to another. There were no differences between congenitally blind, noncongenitally blind, and sighted athletes, either on the level of individual facial actions or in facial emotion configurations. Blind athletes did produce more overall facial activity, but these were isolated to head and eye movements. The blind athletes' expressions differentiated whether they had won or lost a medal match at 3 different points in time, and there were no cultural differences in expression. These findings provide compelling evidence that the production of spontaneous facial expressions of emotion is not dependent on observational learning but simultaneously demonstrates a learned component to the social management of expressions, even among blind individuals. (PsycINFO Database Record (c) 2010 APA, all rights reserved)