Ablation of ice-solids and wax-solids mixtures in turbulent axisymmetric water jets

The ablation rate of frozen mixtures of water or wax with finely divided solids subjected to a turbulent axisymmetric water jet was investigated both experimentally and theoretically. The range of the water jet Reynolds number was 8700–29300 and the jet temperature varied between 22 and 60°C. The solids used were very fine kaolinite clay, titanium oxide and aluminium powder. The type of solids and their concentration were found to affect the ablation rate of ice-solids and wax-solids mixtures. This is mainly due to changes in the physical properties of the melt layer of the water-solids or wax-solids mixtures which forms between the impinging jet and the frozen mixtures.     

滴丸动力黏度的实验研究

复方丹参滴丸是治疗冠心病等疾病的纯中药固体制剂.在滴丸滴制时,滴丸的动力黏度影响滴丸成品的外观质量,如圆整度、硬度、大小和干裂度等.本文研究复方丹参滴丸制剂的含水率和溶化温度对滴丸动力黏度的影响.通过实验测定和数据分析得出,滴丸制剂的溶化温度在75℃~85℃,滴丸制剂含水率为6%~10%的条件下,滴丸的动力黏度值基本恒定,滴丸的滴制效果最佳.实验结果已经用于制订新的生产工艺,指导实际药品的生产.     

链转移剂对丙烯腈共聚物熔融性的影响

采用水相悬浮沉淀聚合法,以水和二甲基甲酰胺(DMF)的混合液为悬浮液、过硫酸钾和亚硫酸氢钠为引发剂、异丙醇为链转移剂,丙烯腈与丙烯酸甲酯在一定温度下发生共聚合反应,研究链转移剂用量对聚合反应和产物性能的影响,结果表明:在反应温度为45℃、单体浓度为30 wt%、单体摩尔比AN/MA为90/10、悬浮液组成水/DMF为90/10(wt/wt)、链转移剂用量占单体的4 wt%时,可以得到可熔融的丙烯腈共聚物.     

连铸结晶器保护渣熔点影响因素的研究

以生产现场实际使用的连铸结晶器保护渣为研究对象,研究碱度、碱金属氧化物含量、Al2O3含量和F含量对保护渣熔点的影响。结果表明,保护渣熔点随Al2O3含量和碱度增大呈先略微降低后逐渐升高势态,随碱金属氧化物和F含量的增加呈先显著降低后趋于平缓趋势。     

尿液喷浆造粒--生产复合肥的一种新工艺

简述了在团粒法工艺的基础上，用尿素熔融尿液或尿素车间二段蒸发器的尿液进行喷浆造粒生产复合肥的改造方案、改造内容、改造效果和投资情况。     

复合氮素缓释剂的缓释机理与防结块作用

介绍复混肥料缓释与防结块处理的一种新技术。利用熔融尿素液代替机械油作为复合氮素缓释剂(由硝化抑制剂和尿酶抑制剂构成)与防结块剂(由石蜡和阴阳离子表面活性物质构成)的载体,其熔融液喷涂在复合肥颗粒表面可短时间在肥料颗粒表面固化,形成坚固的复合包膜层,经防结块测试,6个月的防结块率达94.6%,氮素利用率提高13%。     

纳米锡酸锌/ABS/PVO复合材料阻燃性能研究

采用熔融共混法制备了纳米锡酸锌/丙烯腈-丁二烯-苯乙烯共聚物(ABS)/聚氯乙烯(PVC)复合材料。并对复合材料的冲击强度、阻燃性能进行了测试。结果表明,纳米锡酸锌不但可以提高复合材料的缺口冲击强度,还可以改善复合材料的抑烟阻燃性能。特别是当纳米锡酸锌添加量为6份时,复合材料的阻燃抑烟性能最佳。与未添加纳米填料时相比,纳米锡酸锌/ABS/PVC复合材料的缺口冲击强度达到69．93 kJ/m~2,提高幅度达49．71%。扫描电镜(SEM)分析表明,当纳米锡酸锌在6份时,其在复合材料中呈纳米级分散,且与塑料基体结合良好。     

Crystallization behavior of starch‐filled polypropylene

Starches of different granule sizes, including corn, rice, and amaranth starches, were used to prepare starch‐filled polypropylene (PP) and the effect of starch granule size on crystallization behavior PP was investigated. Differential scanning calorimetry and scanning electron microscopy were used to monitor the energy changes of the crystallization of the melt and to characterize the morphology of PP/starch composites, respectively. Little interaction was observed between starch and PP despite the difference in starch granule size. The crystallization temperature of PP decreased with the addition of starch and this decrease became more apparent with increasing starch granule size. During nonisothermal crystallization, the dependency of the relative degree of crystallinity on time was described by the Avrami equation. The addition of starch decreased the overall crystallization rate of PP, which was attributed to an increase in the activation energy of crystallization under nonisothermal conditions according to the Kissinger equation. An increase in starch granule size of starch would increase the crystallization activation energy of PP and consequently decrease its crystallization rate. © 2004 Wiley Periodicals, Inc. J Appl Polym Sci 92: 484–492, 2004     

无碱玻璃纤维池窑用高致密锆英石砖的研究

采用高纯锆英石为主要原料 ,研究了几个关键工艺因素对高纯高致密锆英石砖性能的影响。结果表明 ,原料纯度、外加物种类及其加入量和烧成温度是获得优质高致密锆英石砖的关键。显微结构分析结果显示 ,这种砖晶粒间呈交错网络结构 ,直接结合程度极高 ,并具有良好的抗玻璃液的侵蚀性和渗透性。扫描电镜检验发现 ,玻璃液渗入砖内与砖反应 ,首先溶解Al2 O3、R2 O等组分 ,然后溶解锆英石 ,并析出斜锆石晶粒 ,呈岛状分布于玻璃液中 ,破坏了砖的原始直接结合结构 ,导致砖的解体。     

熔融晶化法制备硅灰石及其粉碎工艺的研究

以二氧化硅和碳酸钙为主要原料,以碳酸钠、氧化硼和氟化钙为助熔剂,采用熔融晶化法制备了硅灰石。研究了不同粉碎工艺条件对制备针状硅灰石的影响。结果表明,熔融晶化法合成的硅灰石其主晶相为-βCaSiO3。对比两种粉碎方式得出,气流粉碎比介质磨粉碎更有利于保护硅灰石针状晶型,获得的硅灰石粉末的长径比比较大,平均长径比为6.89∶1。