Simulation of deformation and lifetime behavior of a fcc single crystal superalloy at high temperature under low-cycle fatigue loading

This work deals with the formulation of a three-dimensional crystallographic time-incremental lifetime rule for face-centered cubic (fcc) single crystals used for gas-turbine blade applications. The damage contribution rate of each slip system to the total damage is governed by the current values of the resolved shear stress and the slip rate on the corresponding slip system. The damage rule is combined with a crystallographic viscoplastic deformation model. For the nickel-base single-crystal superalloy CMSX4 at 950 °C, various strain- and stress-controlled uniaxial cyclic tests with and without hold-times can be described for different crystal orientations by one set of material parameters. For verification, simulation results for a single-crystal specimen with a notch have been compared with corresponding experimental results. The predicted lifetime is within the factor of two of the measured one.     

Ionic Channels as Natural Nanodevices

Ion channels are proteins with a hole down their middle important in a wide range of biological functions yet simple enough to be analyzed as devices in the engineering tradition.     

Ubiquitous Computing in the Biology Laboratory

Our objective is to eliminate the digital divide that persists between the physical and information spaces of wet-lab based enterprises by embedding computational resources into the shared laboratory environment. Our first challenge is to enable individual lab workers to contribute to a fine-grained formal representation of ongoing lab activities - to build the database by doing the work, without having to stop and write things down in a notebook or to enter information into a computer. By eliminating the redundancy of doing the work and then recording it, accuracy and completeness will be improved. And, by capturing information at a finer detail than is practical for manual entry systems, unanticipated applications can be supported.     

直流上电测试和验证

在电子产品设计中,上电特性测试是产品测试和验证的基础.工程师往往需要对功耗、电源特性、浪涌电流等进行测试和验证.而对于复杂的系统,往往要求多路按时序提供电压和电流、并进行测量的动态直流偏置测试.传统的方式是利用多台仪器构成复杂的测试系统,系统的建立和配置都极具挑战性.本文介绍如何利用Agilent N6705A 直流源分析仪,通过最简单的方式完成复杂而繁琐的系统上电测试和验证.