白点的判据方法研究

最近几年,由于诸多原因,有时在盘环件低倍检验试样面上发现白点裂纹,低倍断口与力学性能检验结果均正常.取试样复验,低倍白点裂纹及断口白亮斑时有时无,裂纹性质难以确认.采用调质断口、缓慢拉伸、金相及蚀坑四种方法对疑白点裂纹的判定方法进行了研究.结果表明虽然调质断口法能判定白点,但是确认率不高;缓慢拉伸法不仅能判定白点,而且还能表明材料的原始状态且准确性较高;金相法是判定白点缺陷的一种简便方法;蚀坑法能反映白点断裂的晶体学取向关系,是研究白点判据的一种辅助手段.     

基于Hoek-Brown准则的Morgenstern-Price法在边坡稳定性分析中的应用

针对目前边坡稳定性计算中破坏准则均为Mohr-Coulomb破坏准则的情况,根据相关准则和原理,推导了基于Hoek-Brown准则的Morgenstern-Price法计算公式.该法克服了一般岩体边坡稳定分析中岩体强度参数纯经验取值的缺点,使计算更为精确、合理.采用具体算例进行对比,探讨了不同准则下边坡稳定性计算的差异原因,并运用基于Hoek-Brown准则的Morgenstern-Price法对安家岭露天矿北端帮滑坡进行了分析.     

Capillary forces and the criterion of stability of the liquid seal between spherical particles

Powder Metallurgy and Metal Ceramics -     

A kinetic criterion for quasi-brittle fracture

A new criterion is proposed for quasi-brittle fracture based on the recognition that quasi-static fracture toughness measurements are merely a limiting case of dynamic fracture. It is found that a unique relationship exists between the energy stored ahead of a loaded crack or blunt notch and the velocity of a crack injected into the material by the failure of a microstructural element lying in the zone of elevated stress. The criterion establishes a minimum velocity required for the continued propagation of the injected crack as a function of the crack tip opening displacement at the instant of crack nucleation. Comparison of the predictions of the model with existing data on various steels and an aluminum alloy show excellent correlation. The implications of the model for phenomena such as the ductile-to-brittle transition, microstructural effects on the resistance to unstable crack propagation and grain boundary embrittlement/strengthening by solute segregation are also explored.     

Evaluation criterion for new programs.

Comments on the use of a rating scale as a criterion for evaluating the success of a program designed to improve police–community relations and on the use of self-reports to evaluate new programs. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Taylor-Russell tables for dichotomous criterion variables.

Considers that the widely used tables of H. Taylor and T. Russell (see pa, vol. 14:1111) for evaluating the usefulness of selection tests are inappropriate for evaluating predictors used to discriminate discrete normally distributed criterion groups where a point-biserial correlation coefficient is the proper index of validity. A set of tables is presented, similar to the taylor-russell tables, for evaluating the usefulness of selection tests where the assumptions require point-biserial validity coefficients. A graphic illustration of the rationale for developing the tables is provided. (PsycINFO Database Record (c) 2010 APA, all rights reserved)