A yang-mills type minimal coupling theory for materials with dislocations and disclinations

Noting that the group $\text{S0(3) ? T(3)}$ may be viewed as a 6-parameter gauge group that leaves the Lagrangian of elasticity theory invariant, the Yang-Mills universal gauge theory construction is used to erect a complete continuum theory of material bodies with dislocation and disclination fields. Breaking of the homogeneity of the action of $\text{S0(3)}$ is shown to give rise to disclinations and rotational dislocations while homogeneity breaking of $\text{T(3)}$ gives rise to translational dislocations. A rigorous justification for replacing displacement gradients by the components of the distortion tensor and Newtonian kinematic velocity by distortional velocity is obtained. Exact determinations are made of the elastic excess forces, the forces on dislocations and the forces on disclinations, and these forces are shown to be totally equilibrating in all instances. Implications of the theory are given and an analysis is made of the field equations and associated dispersion relations that obtain in a disclination free material in the linear elasticity approximation.     

Optical properties of Zitex in the infrared to submillimeter

The results of measurements of the refractive index and power attenuation coefficient of Zitex at 290, 77, and 4 K in the spectral region from 1 to 1000 microm are presented. Zitex is a porous Teflon sheet with a filling factor of approximately 50% and is manufactured in several varieties as a filter paper. Zitex is found to be an effective IR block, with thin (200-microm) sheets transmitting less than 1% in the 1-50-microm range while attenuating < or = 10% at wavelengths longer than 200 microm. Some variation in the cutoff wavelength is seen, tending to be a shorter-wavelength cutoff for a smaller pore size. In addition, the thermal conductivity of Zitex at cryogenic temperatures has been measured and is found to be roughly one half that of bulk Teflon. Finally, its dielectric constant has been measured in the submillimeter as n = 1.20, resulting in extremely low dielectric reflection losses. As a result, Zitex is particularly useful as an IR blocking filter in low-noise heterodyne receivers; in the millimeter-wave range (lambda > or = 850 microm or nu < or = 350 GHz) the attenuation of alpha < or = 0.01 cm(-1) for a 3.5-mm thickness filter of Zitex G125 would raise receiver noise temperatures by <1 K.     

Drinking Water Treatment Plant Design Incorporating Variability and Uncertainty

Both inherent natural variability and model parameter uncertainty must be considered in the development of robust and reliable designs for drinking water treatment. This study presents an optimization framework for investigating the effects of five variable influent parameters and three uncertain model parameters on the least-cost treatment plant configuration (contact, direct, or nonsweep conventional filtration) that reliably satisfies an effluent particulate matter concentration constraint. Incorporating variability and uncertainty within the decision-making framework generates information for investigating: (1) impacts on total cost and treatment reliability; (2) shifts on the least-cost treatment configuration for providing reliable treatment; and (3) the importance of the individual variable and uncertain parameter distributions for reliably satisfying an effluent water quality constraint. Increasing the magnitude of influent variability and model parameter uncertainty results in a greater expected design cost due, generally, to increases in process sizing required to reliably satisfy the effluent concentration constraint. The inclusion of variability and uncertainty can also produce a shift in the locations of the least-cost configuration regions, which are dependent on the expected influent water quality and the magnitude of variability and uncertainty. The additional information provided by incorporating the variable and uncertain parameters illustrates that parameter distributions related to the primary removal mechanism are critical, and that contact and direct filtration are more sensitive to variability and uncertainty than conventional filtration.     

基带SoC的系统解决方案

SoC设计的复杂度在不断增加,同时,市场的压力对产品的质量和交付时间都提出了更加苛刻的要求。本文将以TTPCom公司的CBEmacro3G调制解调器为例,介绍ARM公司在面对当今无线SoC芯片平台设计挑战时的解决方案。     

需求编写十佳经验

需求表述不善可带来毁灭性影响,其所引发的多米诺效应可导致耗时返工、延期交付及预算超支,严重的还可造成业务违规甚至人员伤亡。近年来,随着ISO9000、CMM/CMMI、六西格码等国际标准逐步引入中国,“需求管理”正成为中国当前工程应用和商业热域的热点。目前,有关需求管理的实践大量应用于软件开发工程等领域,软件开发团队在开始一个新的项目之前,会通过详细的用户     

Small is Smarter: Nano MRI Contrast Agents – Advantages and Recent Achievements

Many challenges for advanced sensitive and noninvasive clinical diagnostic imaging remain unmatched. In particular, the great potential of magnetic nano‐probes is intensively discussed to further improve the performance of magnetic resonance imaging (MRI), especially for cancer diagnosis. Based on recent achievements, here the concepts of magnetic nanoparticle‐based MRI contrast agents and tumor‐specific imaging probes are critically summarized. Advances in their synthesis, biocompatible chemical and biofunctional surface modifications, and current strategies for further developing them into multimodality imaging probes are discussed. In addition, how engineered versus unintended surface coatings such as protein coronas affect the biocompatibility and performance of MRI nano‐probes is also considered. To stimulate progress in the field, future strategies and relevant challenges that still need to be resolved in the field conclude this review.     

A conflict-based priority dispatching rule and operation-based approaches to job shops

Job shop scheduling (JSS) problems consist of a set of machines and a collection of jobs to be scheduled. Each job consists of several operations with a specified processing order. In this paper, a job shop model problem is scheduled with the help of the Giffler and Thompson algorithm using a priority dispatching rule (PDR). A conflict based PDR is used to schedule the job shop model by using Genetic Algorithms (GAs). An iterative method is applied to the job model to find the optimal conflict-based PDR order and the operation sequence. The same job shop model is also scheduled based on an operation using simulated annealing (SA) and hybrid simulated annealing (HSA). A makespan of the job model is used as an objective. These four methods are considered as different solutions for each problem. A two-way analysis of variance (ANOVA) is applied to test its significance.     

Capacity Efficiency and Restorability of Path Protection and Rerouting in WDM Networks Subject to Dual Failures

Resilient optical networks are predominately designed to protect against single failures of fiber links. But in larger networks, operators also see dual failures. As the capacity was planned for single failures, disconnections can occur by dual failures even if enough topological connectivity is provided. In our approach the design of the network minimizes the average loss caused by dual failures, while single failures are still fully survived. High dual failure restorability is the primary aim, capacity is optimized in a second step. For WDM networks with full wavelength conversion, we formulate mixed integer linear programming models for dedicated path protection, shared (backup) path protection, and path rerouting with and without stub-release. For larger problem instances in path rerouting, we propose two heuristics. Computational results indicate that the connectivity is of much more importance for high restorability values than the overall protection capacity. Shared protection has similar restorability levels as dedicated protection while the capacity is comparable to rerouting. Rerouting surpasses the protection mechanisms in restorability and comes close to 100% dual failure survivability. Compared to single failure planning, both shared path protection and rerouting need significantly more capacity in dual failure planning.     

Efficient analysis and experimental verification of substrate‐integrated slab waveguides for wideband microwave applications

This article presents a substrate integrated waveguide, named the substrate‐integrated slab waveguide (SISW), which exhibits a wide operation bandwidth. It consists of an integrated rectangular waveguide filled with a periodically perforated dielectric medium. An efficient procedure has been developed for the calculation of the dispersion diagram of SISWs, based on the Floquet theorem, in conjunction with the segmentation technique and the boundary‐integral–resonant‐mode‐expansion (BI‐RME) method. Numerical and experimental results confirm the performance of these waveguides and the efficiency of the analysis method. © 2005 Wiley Periodicals, Inc. Int J RF and Microwave CAE, 2005.     

复合二氧化氯发生器对饮用水消毒的适用性研究

对采用氯酸钠/盐酸法的复合二氧化氯发生器进行了测评和调查,并对其消毒液的成分及消毒后的副产物进行了定量分析.结果表明,复合二氧化氯发生器在实际运行中的转化率仅为30%左右,而在试验模拟条件下的最高转化率也仅为41%左右;在其产生的消毒液中,Cl:量约占Cl2:和ClO2总量的30%～48%;由于消毒液中存在大量氯气和残留的氯酸盐,生成的消毒副产物已经给饮用水安全带来了新的威胁.