普通螺纹检验单—中径与实际中径的探讨

通过对普通螺纹中径诸参数的几何分析,揭示出其单一中径与实际中径的内在联系与区别。从而建立了同一普通螺纹中两者之间的定量关系式;论证了普通螺纹新国标检验单一中径的规定较其旧国标检验实际中径的方法,具有较好的科学性、先进性和实践性;解决了当前普通螺纹加工、检验中,单一中径与实际中径概念上的混乱和生产中的矛盾。     

单一表面活性剂胶束对MBH 和Q-(OH)2之间氢负离子转移反应的影响

在水溶液中，25℃条件下，使用停流法研究了单一表面活性剂胶束对MBH与Q－（OH）2之间的氢负离子转移反应的影响。实验结果表明，离子型表面活性剂和两性表面活性剂对该反应有抑制作用；非离子型表面活性剂对该反应基本无影响。从表面活性剂单体（或胶束）对带电荷的反应物或电荷转移复合物中间体的静电相互作用角度讨论了实验结果。     

单浴液处理银盐全息干板特性研究

为简化卤化银全息干板的处理过程,提出了全息单浴液的处理方法,并对单浴液处理的结果进行了详细的实验研究。     

机场夜航机起降导航控制与管理系统及8098微机的应用

本文论述了一种先进实用的机场夜航机起降导航的控制与管理系统,并阐述了8098单片微机的应用。     

一种新型配料计量控制仪

本文介绍了以单片机51系列为主体的微机电子秤系统的研制过程、设计原理、软硬件概况等。与其他同类控制仪相比,该系统具有结构简单、性能价格比高、使用灵活方便等特点。     

基于单片机控制的温湿度测量系统

文章设计了一种温湿度测量系统,该系统由单片机测量系统和计算机数据管理系统组成,可以对现场的温度和湿度进行实时采集,并通过串行口与计算机进行数据发送与接收.该系统适用于气象、工业、农业、环保、科研等领域的温度、湿度测量与控制,也可用于车站、码头、机场、会议室等场所的环境监测.     

电气化铁路27.5kV单芯电缆接地方式的研究

随着电气化铁路的蓬勃发展,牵引变电系统馈线需要采用电缆方式,为此本文对单芯电缆金属护套感应电势进行计算,得出结论:单芯电缆敷设长度小于1km时,采取一端直接接地、一端保护接地方式;长度为1~2km时,采取电缆中间接地、两端保护接地方式;长度大于2km时,采用金属护套交叉互联接地方式。     

Deformation and damage features of a Re/Ru-containing single crystal nickel base superalloy during creep at elevated temperature

The deformation and damage features of a 4.5%Re/3.0%Ru-containing single crystal nickel-based superalloy during the creep in the temperature range of 1040–1070 °C and stress range of 137–180 MPa was investigated by means of creep properties measurement and contrast analysis of dislocation configuration. The results showed that the alloy exhibited a better creep resistance in the range of the testing temperatures and stresses, the deformation mechanism of the alloy during steady state creep was dislocations climbing over the rafted γ′ phase.In the latter period of creep, the deformation mechanism of the alloy was dislocations shearing into the rafted γ′phase. It is believed that the dislocations shearing into γ′ phase may cross-slip from {111} to {100} planes for forming the K-W locks to restrain the slipping and cross-slipping of dislocations on {111} plane. As the creep goes on, the alternate slipping of dislocations results in the twisted of the rafted γ′ phase to promote the initiation and propagation of cracks along the γ/γ′ interfaces up to creep fracture, which is considered to be the damage and fracture feature of alloy during creep at high temperature.     

Low cycle fatigue properties and microstructure evolution at 760℃ of a single crystal superalloy

Low cycle fatigue(LCF) behavior of a single crystal superalloy was investigated at 760 ℃. Microstructure evolution and fracture mechanism were studied by scanning electron microscopy(SEM) and transmission electron microscopy(TEM), respectively. The results show that the fatigue data fluctuation was small and the fatigue parameters of the alloy had been determined. On increasing the cyclic number, the alloy initially showed slight cyclic softening at the early two or three cycles and slowly hardened to some extent afterwards, then kept stable for the most of the remaining fatigue life. The LCF of the alloy at 760 ℃ can be attributed to the main elastic damage in fatigue processing. The initiation site of fatigue crack was at or near the surface of the samples. Crack propagated perpendicularly to the loading direction at first and then along {111}octahedral slip planes. The fatigue fracture mechanism was quasi-cleavage fracture. The γ'phase morphology still maintained cubic shape after fracture. There were a number of slip bands shear the γ'precipitates and γ matrix near the fracture surface of the specimen. The inhomogeneous deformation microstructure was developed by dislocation motion of cross-slip and a limited γ'precipitate shearing by slip band, stacking faults or single dislocation was observed.     

Single Cu nanowire assembled by microdroplet dielectrophoresis on ultrahigh tensible microelectrodes

At present, study on dynamic tensile properties and atomic chain fabrication of single nanowire, for understanding its dynamic tensile properties and unique physical properties of atomic chain to fabricate atom scale devices, is one of frontier research issues in nanoscale science. However, how to assemble single nanowire on a tensible microstructure becomes one of the most difficult problems, which severely restricts the develop- ment of this research field. In this paper, after the ultrahigh tensible microelectrode chip is fabricated by MEMS technology, hexamethyldisilazane is utilized to improve hydrophobicity of the chip, and then a microdroplet dielectrophoresis experimental platform and technology is developed to assemble single nano- wire on the sensible microelectrode. Experimental results show that accurate and efficient assembly of single Cu nanowire is realized, which contribute greatly to the further research of dynamic tensile properties and atomic chain fabrication. And for guiding the assembly experiments, finite element technology is also utilized to analyze the local microelectro field around the microelectrodes during dieletrophoresis experiments.