容器内可燃气体燃爆温度与压力的计算方法

对容器内可燃气体爆炸过程进行了热力学分析,得出可燃气体在容器内爆炸前后物质热力学能保持不变的结论。根据化工热力学能量守恒方程,推导出了两种容器内可燃气体爆炸温度和压力的计算方法。对几种可燃烃类气体进行了计算,其计算结果与文献值和实验值进行了比较分析,结果表明:燃爆温度的计算偏差为9.14%～11.15%,爆炸压力的计算偏差为5.84%～12.21%,说明了计算方法的有效性和实用性。结合计算实例对两种计算方法进行了阐述,计算结果基本一致。     

工业多元混合气体爆炸极限计算

工业多元混合气中可燃气体与惰性气体的混合按可燃气体的爆炸性及惰性气体的爆炸抑制效果采用全比例分配互相组合的原则进行。只要有惰性气体对可燃气体爆炸抑制效果的基础数据 ,就可以判定由这些气体组成的一切混合气体的爆炸性。对多种不同组分的气体进行了计算 ,并将计算值与文献值进行比较 ,计算误差为± 6% ,该计算方法具有通用性     

炸药爆炸能量的水中测试与分析

介绍了炸药爆炸能量的水中测试方法,对TNT和3种新设计的含铝炸药进行了水中爆炸的实验研究,比较了各炸药的爆炸性能.结果表明,发现冲击波峰值超压、冲量和冲击波能流密度等参数较好地符合爆炸相似律,得到了新配方各参数的爆炸相似律系数.计算了炸药的冲击波能和气泡能,并提出了计算爆炸总能量的方法.把实验测得的炸药的总能量与KHTR程序计算的爆热进行对比,二者符合得较好,说明了KHTR程序可用.     

水下爆炸冲击波传播的近似计算

水下爆炸冲击波传播计算由能流密度一时间曲线经验表达式化简。用简单数值积分法解由拉格朗日形式流体动力学方程、Hugoniot方程和能流密度一时间关系式组成的偏微分方程组,不同距离处的冲击波峰值由单点初始数据计算。结果表明,由近似计算方法所得结果与实测数据和相似律结果一致。适当选取起算参数,在5倍装药半径以外的爆炸远场范围计算精度良好。5倍装药半径以内的爆炸近场,冲击波未充分形成,计算方法失效。计算了几种含铝炸药的冲击波传播,表明冲击波能显著影响冲击波传播特性,冲击波能有利于抑制超压衰减。     

TNT爆炸的数值计算及其影响因素

应用LS-DYNA有限元程序建立了模拟TNT爆炸的数值计算模型并进行了空爆冲击波超压等数值计算。通过数值计算结果与经验公式和试验数据的对比分析,验证了计算模型和参数取值的可信性。基于数值计算结果,分析了炸药材料参数、TNT药量、单元网格密度、建模方式、空气域形状和炸药形状等参数变化对爆炸冲击波超压的影响。结果表明,与试验结果相比,数值计算结果可以作为爆炸冲击波超压的下限值,而Henrych公式、Sadovskyi公式和GB6722-2003公式给出的是超压的中位和下位值;炸药材料参数的取值、单元网格密度和炸药形状对数值模拟结果的影响与比例距离相关,比例距离小于2.0时,不能忽视其影响;冲击波超压会随TNT药量的增加而小幅度增加,但建模方式和空气域形状对数值计算结果的影响可以忽略不计。     

AUTO-DYN模拟炸药爆炸问题的分析

通过CAD/CAE软件建立了不同装药质量与网格尺寸的半无限爆炸场模型,利用AUTO-DYN有限元程序计算出爆炸波的超压值和正压作用时间.将模拟结果与实验数据进行了比较.结果表明,AUTO-DYN有限元程序在模拟爆炸场时,近、中场的计算结果与实验误差相对较大,而远场的计算结果与实验的误差相对较小.计算模型的网格尺寸、计算区域大小和计算机的计算能力对模拟结果有影响.直接使用AUTO-DYN模拟爆炸场对人体的创伤效应存在一定局限性.     

钨粉爆炸压实的计算与研究

根据能量在粉末表面的沉积原理，在总结了大量实验数据的基础上，对纯钨粉的爆炸压实进行了分析和计算，按理论计算结果选择压实多数，得到了具有良好力学性能的钨粉压实体。     

TNT装药水中爆炸的数值模拟

采用AUTODYN软件对不同起爆方式下TNT装药水中爆炸模型进行了数值计算,并对计算结果进行了实验验证.根据计算结果分析了中心起爆、端面中心起爆和端面面起爆情况下,在装药不同方位的水中冲击波压力峰值随距离的变化趋势.计算结果表明,端面起爆状态下,装药径向的冲击波压力峰值均大于端部;中心起爆状态下,一定距离处,装药端面的压力峰值大于径向.改变起爆方式,可以实现水中爆炸冲击波能量的定向增益,提高特定方位爆炸能量利用率.     

混合气体爆炸极限计算应用实例

混合气体在化工设计中多有出现,对于可燃性混合气体,其爆炸极限的计算非常必要.本文举例说明混合气体爆炸极限的计算过程,仅供设计人员在计算混合气体爆炸极限时参考.     

马赫波反射中过度压缩系数的计算

基于采用马赫波反射理论推导出计算过度压缩系数的表达式,根据PBX 9501炸药爆炸后马赫波后压力文献值确定了表达式中各项系数的值。结果表明,该表达式可以反映爆轰产物压力对过度压缩系数的影响;当爆轰波的入射角很大时,也能计算出马赫波后压力的实数解;过度压缩系数不是常数,而是随着爆轰波入射角的增加而减小;当爆轰波入射角一定时,马赫波阵面上从碰撞点到三波点,过度压缩系数逐渐减小。采用过度压缩系数表达式计算出的马赫波后压力与文献值相符,说明该表达式是可信的。     

Effect of the Incorporation of PVC on the Mechanical Properties of the Jute-Reinforced LLDPE Composite

Jute fabrics-reinforced linear low density polyethylene (LLDPE) matrix composites (50 wt% fiber) were prepared by compression molding and mechanical properties were studied. Polyvinyl chloride (PVC) matrix was incorporated instead of LLDPE in the jute based composites and their mechanical properties were investigated and compared with the control composites. It was found that with the increase of PVC in the LLDPE based composites, the mechanical properties were found to improve significantly. Degradation tests of the composites for upto 24 weeks were performed in soil medium. Water uptake and Thermo-mechanical properties of the composites were also studied.     

钛合金胶接接头耐水性的研究

本文介绍了几种表面处理方法对钛合金胶接性能的影响，并讨论了钛合金胶接接头的耐水性能。     

Application of the general rate model with the Maxwell-Stefan equations for the prediction of the band profiles of the 1-indanol enantiomers

The adsorption isotherm data of R- and S-1-indanol and of their racemic mixture on cellulose tribenzoate were measured by frontal analysis. These experimental data were fitted to the single-component and the modified competitive Bilangmuir isotherms. The overloaded elution profiles of bands of the pure enantiomers and of the racemic mixture were calculated for different sample sizes, using the best competitive isotherm model and the General Rate Model of chromatography coupled with the generalized Maxwell-Stefan equation that describes the surface diffusion flux. The calculated and the experimental profiles were found to be in excellent agreement in all cases. The parameters of the model of the mass transfer kinetics were derived from the band profiles obtained for the pure enantiomers. The same values of these parameters give an excellent prediction of the profiles of multicomponent bands. The new model described here allows a satisfactory interpretation of the competitive mass transfer kinetics.     

Dependence of the dyeability of modified cotton on the substituents and the nature of the dye

Cotton cellulose was chemically modified by introducing acrylamide, acrylonitrile and carboxyalkyl moieties in the form of groups or polymers. In carbamylethylated, cyanoethylated and carboxymethylated cotton, these moieties are in monomeric groups, whereas, in graft copolymers of cotton cellulose with acrylamide, acrylonitrile or acrylic acid, the moieties are in polymeric forms. These substrates were dyed independently using direct, acid, basic or reactive dyes. Results showed that at roughly equal nitrogen content, polyacrylamide–cotton graft copolymer exhibited a much higher colour strength than carbamylethylated cotton when the two substrates were dyed using basic dye. The opposite is the case for direct and reactive dyes. The acid dye produced comparable colour strengths. Similar trends were observed when the other samples were dyed with these four dyes. The results were explained in terms of microstructural changes in the physical and chemical structure of cotton caused by the etherification and grafting reactions.     

Effects of the Physicochemical Properties of Metronidazole-Corn Starch Mixtures on the Parameters of the Pellets in the Wet-Granulation Method

Whether the surface free energy of a powder mixture (metronidazole-corn starch) depends on the proportions of the components and how the forces of cohesion and adhesion between the particles affect their interactions as functions of the proportions of the components were investigated. Pellets were produced from the powder mixtures. The interactions between the powder mixtures and the binding agent were first investigated on the basis of the spreading coefficients (S) calculated from the surface free energy. The mechanical properties of the pellets produced were predicted from the S values. Pellet parameters were evaluated as functions of the corn starch content. The overall aim was to investigate the role of the surface free energy of two-component powder compositions in pellet production. In contrast with predictions from the S values, pellets with a more porous and loose texture and with unfavourable mechanical properties can be produced as the S values are increased.     

不同芯材热敏变色微胶囊的制备及性能研究

以隐色染料结晶紫内酯、酚酞、苯酚红、甲基红为电子给予体、显色剂双酚A为电子接受体和十二醇为溶剂,制备了可逆热致变色复配物,以密胺脂为壁材,通过原位聚合法进行微胶囊化研究,并对制备条件进行了优化。利用扫描电子显微镜、热重分析法等对微胶囊进行了结构与性能表征。     

带滤机在种分玛瑙填料生产中的应用

首先介绍了国内外复合材料行业使用的填料氢氧化铝的发展趋势;其次介绍了带式真空过滤机在国内外发展及应用的概况,并对其工作原理做了陈述。最后叙述了其在种分玛瑙生产线上的应用情况、存在问题及解决方法。     

噁二唑啉类化合物合成方法综述

噁二唑啉类化合物由于其良好的生物活性广泛应用于医药,农药领域。将噁二唑啉杂环引入其他化合物中,往往能生成一系列具有广谱生物活性的新化物。因此,在新药设计中,噁二唑啉杂环常被用于化合物的结构修饰。近年来,有关这类化合物的合成方法不断得到更新。作者对近年来噁二唑啉类化合物合成方法及反应机理进行了全面综述。     

碳化塔内壁鼓包的测定与修复

报道了对某化肥厂碳化塔内壁鼓包进行检测的过程和结果以及修复方法。首先对塔内外壁进行了检验。随后对塔体每个筒节和每个鼓包用测厚仪进行壁厚测定,并对选定的鼓包进行切片检验。最后对鼓包进行了修复。修复后的碳化塔运行状况良好。由此总结出碳化塔修复的要求和技术措施,并对该设备的安全运行提出了建议。     

压煮器管束脱落与焊缝渗漏的原因分析及质量控制

分析了压煮器管排焊接时存在的缺陷及改进质量的控制方法