面积坐标法构造含转角自由度的四结点膜元

以四边形面积坐标作为工具,构造了两个含转角自由度的广义协调四边形单元AQ4和lAQ4。它们通过强式分片检验,与同类单元相比,具有很高的计算精度,能消除梯形闭锁现象,有很强的抗网格畸变的能力。     

小井距开发现河油田低渗油藏可行性研究

认为注采井网井距大,水驱控制程度差,采收率偏低是影响胜利油田现河低渗透油藏开发的关键,通过井间密度与水驱控制程度和采收率的关系等分析,提出了现河低渗透油藏开发的合理的井网密度。     

饼干炉湿度控制的改进方法

在大空间的温度控制系统中 ,采用简单的PID控制规律 ,对空间的温度、湿度进行解藕计算 ,将空间的相对湿度控制转化为送风含湿量的控制。该控制方式稳定、可靠 ,并且节约能源。本方法适用于所有的烘烤炉中     

箍筋末端135度弯钩二次就位法讨论

随着人们对建筑安全的日益重视 ,对建筑抗震要求的提高 ,国内外有关规范都对箍筋末端的设置作了明确规定 ,要求做成 135度弯钩。而在工程实践中 ,由于施工上的技术困难 ,很多工程都只设置成 90度弯钩。笔者提出的箍筋末端 135度弯钩二次就位法在基本不增加 90度弯钩施工难度与费用的基础上实现了 135度弯钩的施工 ,其法是可行的     

从关联分析法看如何改善沥青抗老化性能

用灰色关联分析法研究了沥青抗老化性能与沥青化学组成之间的关联程度，结果表明，影响再生沥青性质的主要因素是沥青中的芳烃和胶质的含量。通过添加芳香组分能改善沥青四组分之间的配伍性，从而可以改善再生沥青的抗老化性能。并通过对再生剂进行富芳处理，验证了上述结论。     

IF板与08Al板的成形性能研究

通过模拟成形性试验，对新型超深冲用IF钢板和传统冲压用08Al钢板的冲压成形性能进行了研究．结果表明：IF板的拉深性能、扩孔性能、胀形性能以及“拉深-胀形”复合性能等均优于08Al板，其中，扩孔性能和平面各向异性的改善最为显著；各项试验中，IF板的成形力普遍小于08Al板。     

变形温度和变形程度对Ti－31合金性能和组织的影响

通过高温和室温拉伸试验，研究了变形温度和变形程度对Ｔｉ－３１合金板材性能和组织的影响。结果表明，合金在７５０～８５０℃的温度下变形５％～２０％空冷后，其室温机械性能均能达到材料的技术指标要求。并发现了材料在９００℃的临界变形区。     

Recrystallization/precipitation behaviour in microalloyed steels

Microalloyed high-strength low-alloy (HSLA) steels contain additions of Nb, V, Ti, or in combination, in amounts of 0.01 to 0.1 weight percent to improve mechanical properties, which are strongly dependent on the thermomechanical interaction taking place in the course of rolling mill processes. The recrystallizatian of hat-twisted austenite has been investigated in a cylindrical specimen (f 6×50 mm) machined from hat rolled plates of 0,052 wt % Niobium microalloyed steel. Continuous and interrupted torsion test were carried out in the temperature range 1123 K to 1173 K after a solution treatment of 1.5 minutes at 1423 K and torque-twist data were analysed. The various methods were discussed for obtaining results from torsion tests. The effect of precipitation kinetics was appreciated by way of connection t_p/t_p(red), where t_p is the experimental measured time for the peak stress and t_p(red) is the newly defined reduced time. The softening ratio X and time t_0.05R for start of static recrystallization were established.

The correlation between precipitation and recrystallization is presented as a graphs for chosen requirements (temperature of austenitization, carbon and niobium content and strain rate). If temperature goes below 850°C, the restoration processes are hardly suppressed, both are limited by diffusion and Nb(CN) precipitation, which are extended dynamically in the range of strains rates 10⁻² to 1 s⁻¹.

In the present paper, an attempt is made to derive the PRTT diagram and to define all mathematical equations for describing recrystallization times t_0.05R, t_0.5R, t_0.95R and t_0.05P for the start of precipitation. In real metal forming processes such as the hot rolling of plates or strips the knowledge of these parameters and results is extremely important for the the correct microstructure and sheet quality to be obtained.     

阳离子化多元醇防塌剂的研制

室内研究和现场应用表明,聚乙烯醇类防塌剂表现出较明显的增粘负效应,可引起钻井液粘度的急剧增加,严重影响其推广应用.通过金属盐催化降解和阳离子化反应,研制出了抑制性好且增粘负效应低的阳离子化改性多元醇防塌剂.考察了阳离子化试剂、反应温度、反应时间对取代度、反应效率和产品主要性能的影响,得出了阳离子化多元醇防塌剂最佳制备条件,即：PVA与阳离子化试剂物质的量比为1：1,反应温度为50℃,反应时间为4 h,阳离子度可达0.435.     

多时滞Lotka-Volterra互惠系统周期正解的存在性

用重合度理论研究具时滞非自治Lotka-Volterra互惠系统，获得了周期正解的存在性，推广了Gopalsamy及He(1997)的结果。