Li_20对AlN陶瓷低温烧结的影响

利用XRD,SEM和TEM研究了Li2O-CaF2-Y2O3体系在/AlN陶瓷低温烧结中的作用机理,研究发现,添加Li2O的/AlN陶瓷有着更低的收缩开始温度和更大的收缩率,这种收缩来自于含Li玻璃相与CaYAlO4液相的共同作用。在烧结过程中,Li2O不仅改变了AlN烧结过程中的相组成,而且改善了液相的性质。由于Li2O和Al2O3在l 100℃以下反应生成含Li玻璃相,使得AlN开始收缩的温度大为降低。在1 600℃以上,含Li玻璃相分解散失,有利于AlN晶界的纯化,同时,CaYAl3O7向CaYAlO4的转变以及液相CaYAlO4在烧结过程中稳定存在,保证了含Li玻璃相散失后AlN的持续收缩。     

化学工业推行清洁生产势在必行

本文介绍了清洁生产的内容,阐述了化学工业推行清洁生产的必要性、主要障碍和促进化工清洁生产的重要因素,并以实例说明清洁生产给企业带来的效益。     

石化企业循环水系统的节水运行与管理

围绕工业循环冷却水系统的工艺原理及水质特点，全面分析阐述了石化循环水系统开展节水运行管理的途径方法及其注意事项，天津石化公司乙烯厂在此方面取得了良好的效果。     

钢筋在堆石料中的拉拔试验研究

作为一种有效的土石坝抗震加固措施,加筋在高土石坝建设中正被越来越广泛地运用。钢筋与堆石料接触特性及影响因素研究是合理进行加筋设计的前提。通过室内拉拔试验研究了钢筋与堆石料的界面摩擦特性,揭示了不同上覆压力、堆石料含水状态、堆石料级配及孔隙率等因素对试验结果的影响。结果表明,堆石料与钢筋接触面剪应力与拉拔位移曲线呈下端开口的抛物线形状,上升段陡于下降段,残余剪应力数值不稳定;4个影响因素中,上覆压力与峰值剪应力曲线近似于线性正比关系;孔隙率和峰值剪应力曲线类似于线性反比关系;级配平均线的峰值剪应力与拉拔位移曲线位于级配上包线的试验曲线之上;饱和含水状态下堆石料的峰值剪应力与拉拔位移曲线远低于风干状态。     

Honey bees mating optimization algorithm for process planning problem

Process planning is a very important function in the modern manufacturing system. It impacts the efficiency of the manufacturing system greatly. The process planning problem has been proved to be a NP-hard problem. The traditional algorithms cannot solve this problem very well. Therefore, due to the intractability and importance of process planning problem, it is very necessary to develop efficiency algorithms which can obtain a good process plan with minimal global machining cost in reasonable time. In this paper, a new method based on honey bees mating optimization (HBMO) algorithm is proposed to optimize the process planning problem. With respect to the characteristics of process planning problem, the solution encoding, crossover operator, local search strategies have been developed. To evaluate the performance of the proposed algorithm, three experiments have been carried out, and the comparisons among HBMO and some other existing algorithms are also presented. The results demonstrate that the HBMO algorithm has achieved satisfactory improvement.     

油田联合站油水分离的模糊-PID控制

联合站油水分离过程是将高含水原油处理成为合格产品的重要生产过程，从控制理论角度看，此过程具有多变量、干扰因素复杂、非线性、大滞后、压力与界面强耦合的特点，为了实现此过程的自动控制，本文针对典型的两段式脱水工艺进行了理论分析，通过对人工智能控制经验的总结，确定了模糊-PID控制策略。     

硅酸盐激光玻璃的离子交换增强

用离子交换法能使硅酸盐激光玻璃机械强度增加２－３倍，激光强度增加３倍，从而弥补了自身热光系数较大的缺点。虽然玻璃在处理后，阈值稍微升高，效率稍有下降，但因允许输入更大的能量，使输出得到３倍的增加，说明了离子交换增强方法是成功的。     

Poly(etherimide)/montmorillonite nanocomposites prepared by melt intercalation

A novel aromatic amine organo‐modifier synthesized in our previous work was used to treat montmorillonite (MMT) and the organo‐modified MMT was used to prepare poly(etherimide) (PEI)/MMT nanocomposites by a melt intercalation method. MMT treated by this amine exhibited large layer‐to‐layer spacing and a high ion‐exchange ratio (>95%). The nanocomposites were characterized with X‐ray diffraction (XRD), transmission electron microscopy (TEM), dynamic mechanical analysis, a universal tester, thermogravimetric analysis, and by differential scanning calorimetry. The results of XRD and TEM showed that the nanocomposites formed exfoliated structures even when the MMT content was 10 wt %. When the MMT content was below 3 wt %, the PEI/MMT nanocomposites were strengthened and toughened at the same time. The nanocomposites also showed marked decreases in coefficient of thermal expansion and solvent uptake. © 2003 Wiley Periodicals, Inc. J Appl Polym Sci 90: 1857–1863, 2003     

2,6-二氟苯甲酸合成工艺研究

为优化2,6-二氟苯甲酸(DFBA)的合成工艺,以2,6-二氯苯腈(DCBN)和氟化钾为原料,N,N-二甲基酰胺(DMF)为溶剂,在聚醚类催化剂A的催化下氟代合成中间体2,6-二氟苯腈,然后中间体在碱性条件下水解制得(DFBA).试验结果表明,合成DFBN的最佳条件为:DCBN在DMF中的质量浓度为0.38g/mL,KF的量为DCBN的量的2.3～2.4倍,反应时间10 h,最高收率93.5%;合成DFBA时,以质量分数为20%的NaOH为介质,反应时间9 h,收率≥92%.收率93.5%,纯度99.7%.该工艺收率高、三废排放少,可节省成本,有望工业推广.