低负荷维氏硬度法的负荷选择

本文按照维氏硬度测定的技术条件,将基本公式H_v=1854P/D~2加以变换,从而得到一些较为简单的数学关系式.利用这些关系式,可以对不同金属薄带材料,很容易计算出较合理的负荷大小,既能保证不被"打穿",也使视场内有一个适合观测的压痕图象.     

让案例教学走进高职计算机学科

"案例教学法"(CaseStudy)是一种以案例为基础的教学法,把真实的情景进行典型化处理后供学生思考分析和决断,让学生分组自助谈论和研究,从而提高学生对于问题的分析和解决的能力。     

相关函数脉冲响应法系统实时辨识

结合了相关函数法和脉冲响应法两种经典系统辨识方法原理,在随机信号干扰的情况下,设计对系统实现实时辨识的仿真软件,获得系统的非参数模型。该仿真设计中,以M序列作为输入信号,白噪声信号作为干扰信号,进行了Matlab仿真实验,讨论了M序列的幅值,采样时间和周期长度对系统辨识效果的影响,以及分析M序列的选取方法来减少系统辨识误差。     

Cu—Cr合金电极触头板铸件的熔制

含０．４％～１．０％Ｃｒ的Ｃｕ－Ｃｒ合金具有优良的导电、导热性能，铸件经热处理强化后可获得较高的综合力学性能。近年来该合金作为一种新材料被广泛地用于制作电子工业、电器设备上的电极触头板、接触环、夹持体等零件。Ｃｕ－Ｃｒ合金存在易氧化吸气、凝固范围窄、收缩较大、易形成集中缩孔等缺陷，这些铸造特性给生产优良的Ｃｕ－Ｃｒ合金铸件带来一定的困难。以采用常规的熔炼设备和造型材料熔铸出Ｃｕ－Ｃｒ合金铸件——高压大电流电极触头板为例讨论这一熔铸的工艺方法。     

Simulation Method of Dynamic Characteristics of Turbine Flow Sensor

Computational Fluid Dynamics (CFD) simulation is one of the important methods to study the performance and in-fluencing factors of turbine flow sensors. According to the working characteristics of the turbine flow sensor, the passive simulation method based on the six degrees of freedom (6-DOF) model and dynamic mesh is proposed in this paper. The reliability of the simulation method is verified by steady-state experiments and unsteady-state experiments. The results show that the trend of meter factor with flow rate acquired from the simulation is close to the experimental results, and the deviation between the simulation result and the experiment result is low with a maximum deviation of 2.88%. In the unsteady simulation study, the impeller speed changes with the inlet velocity of the turbine flow sensor, which has a good follow-up. The passive simulation method can be used to predict the dynamic performance of the turbine flow sensor.     

Modeling of Intercritical Heat Treatment of DP and TRIP Steels

The final microstructure of DP and TRIP assisted steels can evolve after hot working (hot rolling) or during post heat treatment process. In the formation of the final structure a number of different technological parameters have important roles, e.g. end temperature of rolling, cooling rates, temperature of intercritical annealing, etc. As a result of the individual factors and their combinations a lot of product technology routes are feasible. The effect of the different combinations of these technological parameters on the microstructure can be mapped by the special Jominy end-quench test (so called intercritical Jominy end-quench test) described in this paper. Unlike the traditional Jominy test, in this case there is a partial anstenizing between A1 and A3 temperatures which results in a given amount of ferrite in the microstructure before quenching. The method developed can be applied for mapping DP and TRIP assisted steels' microstructure in a wide range of technological parameters. The analysis of measured and calculated data can help us find the technological parameters optimal from the microstructural point of view.     

关于复杂黄铜的等效方法及其它

在复杂黄铜等效变换的多元变化过程中，存在着第三种当量系数Ｉ。它是确保合金转化为二元形式所必不可少的导向给定值，是一个定位常数。找出了Ｋ＋Ｊ＝０的误解的产生原因，论证了Ｋ＋Ｊ＝１所在达的过程的实质。指出用二元相图理解等效变换这一三元变化过程的认识误区。     

压痕法测定热压MoSi2基复合材料K1C值的研究

用不同的压痕方程计算了纳米ＺｒＯ２粒子韧化ＭｏＳｉ２基复合材料的室温断裂韧性Ｋ１ｃ值，同时研究了压痕载荷对Ｋ１ｃ值的影响。结果表明，试验材料在试验条件下的断裂韧性不遵从半月状裂纹系统方程，而遵从巴氏裂纹系统方程，其室温压痕断裂韧性保持与压痕载荷的独立性。     

催化动力学光度法在贵金属测定中的实际应用

综述了催化动力学光度法在钌、铑、钯、银、锇、铱、铂等贵金属测定中的实际应用新近发展状况。     

液相沉淀法制备超微钴蓝颜料

研究了以硝酸铝,硝酸钴等为原料,采用液相沉淀法合成具有尖晶石型结构钴蓝颜料的制备方法。系统讨论了沉淀剂种类(氢氧化钠,氨水,尿素)、反应溶液浓度、洗涤方法、分散剂等工艺因素对合成钴蓝颜料粒度和光学性能的影响。采用SEM、TEM观察了合成颜料的形貌。最终制备出二次粒径中位径d50为670nm,一次粒径在45nm左右的超微钴蓝颜料。