硫酸工业中常见气体有效能计算

介绍理想气体、理想气体混合物、真实气体、真实气体混合物的有效能计算方法，并以硫酸工业中常见气体为例加以说明。通过编写计算机程序进行计算，可实现有效能的快速分析，便于实际应用。     

射流流化床内流体力学行为的模拟研究

以流化床应用为代表的气固流动系统是许多化工过程中的重要组成部分 ,CFD( computational fluid dynamics)方法能够为其优化设计和放大提供所需要的信息 .本文采用双欧拉模型 ,与 Gidaspow等的实验结果进行了对比 ,模拟了二维射流流化床内气泡的形成规律 ,得到了带锥型分布器的流化床内瞬时空隙率和气固相速度分布等流体力学参数 .对锥型分布器流化床的实验结果表明 ,模拟得到的气泡的形状与实验现象相接近 .     

Morphologies-Controlled Synthesis and Optical Properties of Bismuth Tungstate Nanocrystals by a Low-Temperature Molten Salt Method

Well-crystallized bismuth tungstate (Bi₂WO₆) powders with different morphologies were successfully synthesized via a low-temperature molten salt method. The powders were characterized by X-ray diffraction, transmission electron microscopy, and UV-Vis, respectively. It was found that the variation of morphology of the obtained Bi₂WO₆ powder mainly depends on the different reaction temperatures and the weight ratio of LiNO₃–NaNO₃ salt to precursor. In addition, the UV-Visible absorption spectra showed that the synthesized powders had strong light absorption properties not only in the ultraviolet light but also in the visible light region.     

乳液聚合中单体醋酸乙烯酯与保护胶体聚乙烯醇的接枝反应研究

研究了以聚乙烯醇为保护胶体的醋酸乙烯乳液聚合中,聚乙烯醇与单体的接枝反应。探讨了引发剂用量、聚合反应温度、保护胶体聚合度等因素对接枝反应的影响。     

Preparation,characterization and salt-resistance of a coal based super absorbent composite

Potassium humate was extracted from brown coal.A novel super absorbent composite,poly (acrylic acid-co-acrylamide)/potassium humate (PAA-AM/KHA),was prepared by graft polymerization of acrylic acid,acrylamide and coal based potassium humate using N,N'-methylenebisacrylamide as a crosslinker and potassium peroxydisulfate as an initiator.The effects of reaction temperature,degree of neutralization of the poly (acrylic acid) and the amounts of crosslinker,initiator and potassium humate were investigated.Salt resistance tests were also carried out.The composite prepared under optimal conditions had a potassium humate content of 10% and exhibited a water absorption of 770 g/g in distilled water,and 349,286 and 41 g/g in 0.5 mol/L KC1,MgCl2 and AlCl3 solutions respectively.The results indicate that the salt resistance of PAA-AM/KHA was superior to that of poly (acrylic acid-co-acrylamide) because of the collaborative effect of functional groups of the coal based potassium humate.The PAA-AM/KHA micro powder was characterized by IR spectroscopy and the micrographic surface was characterized by scanning electron microscopy.Introduction of potassium humate into the poly (acrylic acid-co-acrylamide) structure creates a composite more suitable for use as a water-managing material in the renewal of arid and desert environments.The salt resisting property of the composite is improved,production costs are reduced and the growth stimulant effect is still present.     

An improvement to the simulation of phase-change heat-transfer during soil freezing and thawing

A new variable time step method, which is called the backwards calculating time step method, is presented in this paper. It allows numerical simulation of soil freezing and thawing while avoiding "phase change missing and overflowing". A sensitive heat capacity model is introduced through which the calculation errors are analyzed. Then the equation using the self-adjusted time step is presented and solved using finite differences. Through this equation, the time needed for a space cell to reach the phase change point temperature is calculated. Using this time allows the time step to be adjusted so that errors caused by "phase change missing and overflowing" are successfully eliminated. Above all, the obvious features of this method are an accelerated rate for adjusting the time step and simplifing the computations. An actual example proves that this method can accurately calculate the temperature fields during soil freezing and thawing. It is an improvement over traditional methods and can be widely used on com- plicated multi-dimensional phase change problems.     

网络媒介影响下建筑相关问题初探

自工业革命以来形成的社会生活方式,在信息数字技术的影响下发生着悄无声息的变化.从原子到比特,数字化生存是必然的趋势.网络媒介的出现使得人们在交流和机会等方面获得平等的权利.随之产生的人们的生活方式、行为的改变已经为艺术领域带来了新的变化.通过对艺术创作的考察,为建筑领域的相关问题提供了参照、借鉴.在建筑创作中,＂图＂与＂底＂的关系正在模糊化,信息交流方式更多样化并具有一定的阶段性,动态的模数将导致更具个性化的设计,空间界面更为柔化,设计成果的生成也具有了更多的不可预见性.     

图像阈值自动选取算法的C＋＋实现

图像分割是运动目标检测与跟踪技术必须要解决的问题,在很多时候它涉及到图像阈值的选取。文章采用的算法首先计算图像中不同区域的灰度均值,结合最小差值条件,反复修订由计算所得的阈值,从而达到自动选优的目的。在此基础上,文章进一步给出了用C＋＋语言实现算法的关键代码。测试表明此方法选择阈值简便实用,图像的二值化效果良好。     

催化裂化装置自保的改进方案

介绍催化裂化装置自保系统,以及自保系统的校验与维护。     

高功率移相器粘接工艺初探

主要介绍了粘接技术在高功率铁氧体移相器上的应用。通过对其工艺途径及关键工序的控制，提出了采用粘接技术完成高功率移相器铁氧体的连接，不仅可以大量地缩短工作时间，而且可以使制造成本大幅度降低。