转相法低温丁苯胶乳改性乳化沥青的制备

采用转相法低温制得了性能良好的丁苯胶乳改性乳化沥青,研究了乳化剂等对沥青乳液稳定性的影响,并讨论了改性沥青的部分性能。结果表明,使用质量分数为2.8%的十六烷基三甲基氯化铵/烷基聚氧乙烯基双季铵盐/聚氧化乙烯烷基醚(质量比1∶1∶3)复合乳化剂,沥青乳液的稳定性能满足T0655—1993标准的要求;Ca2 、NH4 的浓度分别小于1.44,2.34mmol/L时对乳液的稳定性影响不大;当丁苯胶乳与沥青乳液质量比为1∶8时,试样的黏结强度、拉伸强度、扯断伸长率分别达到0.21MPa、0.34MPa、210%,性能达到JC/T408—1996标准的要求。     

聚丙烯酰胺改性淀粉用于洗羊毛废水的处理

以聚丙烯酰胺改性淀粉作为化学絮凝剂对青海毛纺厂的洗毛废水进行絮凝处理，处理效果十分理想。COD及固体悬浮物去除率分别达95％及97％以上。絮凝污泥以溶剂甲苯进得革取回收，得羊毛脂。该法工艺简单，综合效益好，有工业推广价值。     

新型改性环氧水泥浆试验设计及其应用研究

研制了一种新型改性环氧水泥浆,对其在混凝土粘结补强中的应用进行试验分析。试验设计主要考察固化剂含量、水泥用量及粗糙度对粘结效果的影响。结果表明,该新型改性环氧水泥浆克服了普通环氧浆体在潮湿环境下不能很好固化的弱点,与湿浇新混凝土有较强粘结力,用作粘结界面剂能有效提高新老混凝土粘结性能,且具有施工性能良好、经济适用等优点,适于实际混凝土修补加固工程中大面积推广使用。     

Imposition of boundary conditions by modifying the weighting coefficient matrices in the differential quadrature method

One of the important issues in the implementation of the differential quadrature method is the imposition of the given boundary conditions. There may be multiple boundary conditions involving higher‐order derivatives at the boundary points. The boundary conditions can be imposed by modifying the weighting coefficient matrices directly. However, the existing method is not robust and is known to have many limitations. In this paper, a systematic procedure is proposed to construct the modified weighting coefficient matrices to overcome these limitations. The given boundary conditions are imposed exactly. Furthermore, it is found that the numerical results depend only on those sampling grid points where the differential quadrature analogous equations of the governing differential equations are established. The other sampling grid points with no associated boundary conditions are not essential. Copyright © 2002 John Wiley & Sons, Ltd.     

从煤焦油软沥青和苯基硅烷制备硅取代聚芳烃中间相的研究

过滤后的煤焦油沥青分别与一,二,三,四苯基硅烷在1MPa氩气气氛和420℃～460℃温度下共炭化,合成了硅取代聚芳烃中间相。在四种合成中间相中,元素硅的起始加入量均为2%。测定了裂解残留物和硅的收率、可溶性、玻璃转化温度以及裂解残留物的炭收率;并分别以偏光显微镜和电子探针微分析法考察了残留物的微结构和相应的硅分布,硅的收率取决于不同的苯取代硅烷的挥发性和反应性。裂解残留物显示出三种不同的共存相:(a)含有粗镶嵌织构和痕量硅的光学各向异性相;(b)硅含量较高的光学各向同性相;(c)含细镶嵌织构和中等硅含量的光学各向异性相。最后这种中间相主要来自二,三苯取代硅烷与煤沥青的共炭化,是由于硅取代聚芳烃中碳原子并破坏了其分子的平面结构而引起的。     

纸张用氨基改性聚醚硅油柔软剂的合成

以氯铂酸为催化剂，利用含氢硅油（PHDS）与烯丙基聚醚（APE）的硅氢加成反应，合成出聚醚改性硅油；然后用乙醇胺进行胺化反应，制成纸张用氨基改性聚醚硅油柔软剂，硅氨加成反应的最佳工艺条件为：PHDS与APE的质量比为1:8，时间为4h，温度90～120℃，使用氨基改性聚醚硅油后，纸张的柔软度增加，但强度下降。     

气液活塞泵数值计算的修正特征线法

本文研究了气液活塞泵的运动机理，提出了一种用于定常振荡流数值计算的“修正特征线法”.在常规特征线法的基础上，通过将“时间修正因子”引入运动方程，不仅统一了变波速多介质段计算节点的特征线斜率，保证计算在矩形网格上进行，而且还在一定程度上提高了计算速度.文章推导了修正特征线法的特征型微分方程及差分方程：针对单介质管路和多介质管路分别提出了不同的处理方法；并在最后给出了气液活塞泵定常振荡流计算实例，与试验结果的对比一方面验证了“修正特征线法”计算变波速多介质段定常振荡流问题的优越性，另一方面也提出该方法在精度分析和敛散性方面尚需进一步研究.     

新鲜瘦肉的换气包装技术

采用换气包装技术包装新鲜瘦肉可以有效地延长新鲜瘦肉的货架寿命。换气包装技术主要包含真空包装和充气包装二个工艺过程。文中给出了充填气体和包装材料的选用方法。     

数字音频变调算法的研究

变调是一种用途广泛的音频处理手段，但有关的技术资料很少，并且介绍得不详细。由此提出了一种频域实现的算法，能有效实现变调不变时间，并达到较好的相位连续性，实验证实效果良好。     

Microbiological, physicochemical and organoleptic changes in dry-salted olives of Thassos variety stored under different modified atmospheres at 4 and 20 °C

Microbiological, physico-chemical and organoleptic changes were studied in dry-salted olives, cv. Thassos, stored under different atmospheres (100% carbon dioxide and nitrogen, 40% CO₂/30%O₂/30%N₂ and air) at 4 and 20 °C for 180 days. The initial microbial flora comprised of yeasts, no lactic acid bacteria, enterobacteria, pseudomonads or Staphylococcus aureus were detected, as the low water activity/high salt content does not favour their growth. At 4 °C, the population of yeasts declined steadily throughout storage but to a different extent depending on the gaseous atmospheres. At 20 °C, there was an initial decline in yeast counts in all samples followed by a steady increase until the end of the storage period. The CO₂ atmosphere was most effective at keeping the number of yeasts low at both storage temperatures. All gas atmospheres prevented fungal growth at both temperatures apart from the samples stored in air. The pH, a_w and salt content of the olives did not change significantly throughout the storage period. The prevailing yeast species was the salt tolerant Candida famata . The organoleptic characteristics did not differ significantly among differently treated olives. However, increased rancidity and reduced fruit colour was observed in the samples stored at 20 °C.