Statistical Tensile Strength for High Strain Rate of Aramid and UHMWPE Fibers

Technora,madefromaramidfibersandsome whatsimilartothecommonlyknowKevlar,and Ultrahighlyorientedhighmolecularweightpolyeth ylene UHMWPEfibersarealloftenusedinflexible armourapplicationsandhencesubjectedtohighrates ofloading.Theutilizationoftheirreinforcedcom positesarmourincertainballisticapplicationsisin creasinglypreferredoverconventionalrigidmetalar moursystemsbecauseofitssuperiorstrength to weightratioandflexibility.Todate,thedesignand developmentofsuchfabricarmoursystemshave largelybeen…     

增广矩阵法的改进算法及程序实现

介绍了一种改进的增广矩阵法和主要的程序流程图，可用于线性控制系统的数字仿真，特别适用于病态系统。仿真结果表明，该法仿真精度比四阶龙格一库塔法提高二个数量级。     

Automatic h-Scaling for the Efficient Time Integration of Stiff Mechanical Systems

When solving stiff mechanical systems, implicit time integrators overestimate the error and tend to use small stepsizes due to the order reduction phenomenon. This article introduces an algorithm for the detection of stiff components that allows automatic scaling of the stepsize h in the error estimation. It is based on an investigation of the local error and applies existing embedded formulas of implicit Runge–Kutta methods. Thus, implementation and calculation effort are low. Three examples are integrated with the code RADAU5, a linear DAE in two different formulations and a slider crank mechanism.     

Component-Based Derivation of a Parallel Stiff ODE Solver Implemented in a Cluster of Computers

A component-based methodological approach to derive distributed implementations of parallel ODE solvers is proposed. The proposal is based on the incorporation of explicit constructs for performance polymorphism into a methodology to derive group parallel programs of numerical methods from SPMD modules. These constructs enable the structuring of the derivation process into clearly defined steps, each one associated with a different type of optimization. The approach makes possible to obtain a flexible tuning of a parallel ODE solver for several execution contexts and applications. Following this methodological approach, a relevant parallel numerical scheme for solving stiff ODES has been optimized and implemented on a PC cluster. This numerical scheme is obtained from a Radau IIA Implicit Runge–Kutta method and exhibits a high degree of potential parallelism. Several numerical experiments have been performed by using several test problems with different structural characteristics. These experiments show satisfactory speedup results.     

最大界面剪切应力的估算与芳纶复合材料界面粘结的表征

研究以估算的最大界面剪切应力，表征芳纶Ｋｅｖｌａｒ４９复合材料的界面粘结。依据Ｇｒｅｓｚｃｚｕｋ模型和单纤维拔出实验数据估算最大界面剪切应力，研究纤维表面处理和基体改性对界面粘结的影响。选用不同活性基团表面的芳纶Ｋｅｖｌａｒ４９和两种耐高温树脂基体组成强粘结界面体系的研究结果表明，实验数据与理论曲线拟合很好。     

Linear microstrip surface coil for MR imaging of the rat spinal cord at 4.7 T

A new design of RF coil based on a quasi-transverse electromagnetic field is described. The coil was developed for the acquisition of MR images of the rat spinal cord at 4.7 T. Different materials for the construction of the coil were tested, and the best results were obtained with Teflon. The design of the microstrip coil enables the investigator to change the length of the coil in a longitudinal direction and yields a relatively high signal-to-noise ratio due to the restricted field of view. Low RF field penetration depth also helps in suppressing motion artifacts generated by, e.g., breathing or heartbeats.     

9．00R20全钢载重子午线轮胎胎体骨架材料研究

为适应9.00R20轮胎实际使用的需要,采用3+9+15×0.22+0.15钢丝帘线作为胎体骨架材料,对胎体强度与胎侧曲挠变形以及胶与钢丝帘线的粘合力进行了分析、研究、改进.产品经过实际使用性能考核,达到改进设计目的,克服了胎侧"拉链式"爆破病疵,提高了轮胎使用安全性.     

Time Stepping Via One-Dimensional Padé Approximation

The numerical solution of time-dependent ordinary and partial differential equations presents a number of well known difficulties—including, possibly, severe restrictions on time-step sizes for stability in explicit procedures, as well as need for solution of challenging, generally nonlinear systems of equations in implicit schemes. In this note we introduce a novel class of explicit methods based on use of one-dimensional Padé approximation. These schemes, which are as simple and inexpensive per time-step as other explicit algorithms, possess, in many cases, properties of stability similar to those offered by implicit approaches. We demonstrate the character of our schemes through application to notoriously stiff systems of ODEs and PDEs. In a number of important cases, use of these algorithms has resulted in orders-of-magnitude reductions in computing times over those required by leading approaches.     

帘线钢72A精炼过程研究

对首钢帘线钢72A精炼过程的钢液中酸溶铝、总氧、夹杂物成分和形貌进行了系统的分析,发现从LF结束到VD开始过程中酸溶铝增加很大;VD精炼处理后夹杂物熔点高.分析得出合金中铝以及喂Si-Ca丝导致了钢中酸溶铝的增加;夹杂物中CaO含量过高、SiO2含量过低导致精炼结束后夹杂物处于高熔点区.提出降低脱氧剂中Ca含量,取消喂丝以及降低精炼渣碱度的改善措施.     

Romantic attachment in individuals with physical disabilities.

Objective: To examine the relationship between adult attachment style and physical disability in intimate romantic relationships. Method: Participants were 50 individuals with adult-onset spinal cord injuries (SCI) and 50 individuals with congenital disabilities (CON) living in the community. The main outcome measures were adult attachment style and dyadic relationship adjustment. Results: Participants with SCI and CON did not differ in rates of secure versus insecure attachment, and the rates of neither group differed significantly from rates reported for persons without disability. Dyadic adjustment was clearly predicted by attachment variables and differed between the participants with SCI and those with CON; individuals with SCI reported greater total dyadic adjustment. Avoidance showed a strong negative association with dyadic satisfaction, but no association was found with dyadic cohesion. Social participation variables were associated with dyadic adjustment. For instance, mobility was positively associated with dyadic satisfaction. Conclusions: Dyadic adjustment in people with disabilities, as in other groups, is affected by attachment style, but disability and social participation variables may also affect dyadic adjustment. Clinicians should consider differences in attachment styles among persons with disabilities and their implications for intimate close relationships. (PsycINFO Database Record (c) 2010 APA, all rights reserved)