Morphology and thermal stability of BR/clay composites prepared by a new method

A new potential preparation method named in situ organic modification was used to prepare intercalated polybutadiene rubber (BR)/clay/dimethyl dihydrogenated tallow ammonium chloride (DDAC) composites. That is, BR, pristine clay, and intercalatant DDAC were directly mixed in a Haake rheometer without pretreating the pristine clay with the intercalatant. The morphology of the BR/clay composites was investigated by means of X‐ray diffraction and scanning electron microscopy. The thermal stability of the BR/clay composites was analyzed by thermogravimetric analysis (TGA). The dispersion of clay particles in the BR/clay/DDAC composites is much better than that in the BR/pristine clay and similar to that in the BR/organoclay DK4 (modified with DDAC) composites. BR/clay/DDAC composites have much higher thermal stability than the gum BR, BR/pristine clay, and BR/DK4 composites. The clay/intercalatant ratio has little influence on the thermal stability of the BR/clay/DDAC composites, while clay content has a significant effect on their thermal stability. The enhanced thermal stability of the BR/clay/DDAC composites is related to the dispersion state of clay particles in BR. © 2005 Wiley Periodicals, Inc. J Appl Polym Sci 99: 905–913, 2006     

基于仿射传播的有向网络聚类算法

现有大多数的网络聚类方法都只是针对无向网络, 已有的有向网络聚类方法建立在传统聚类算法基础之上, 存在着一定的局限性。针对上述问题, 提出一种基于仿射传播的有向网络聚类算法, 该算法首先采用SimRank作为节点之间的相似度, 并将计算得到的结果转换为适应于仿射传播算法的负值; 然后将相似度矩阵作为输入, 利用具有更好性能的仿射传播算法对有向网络进行聚类。实验结果表明, 所提出算法的聚类性能优于其他几种具有代表性的有向网络聚类算法。     

Novel method for preparation of quaternary ammonium ionomer from epoxidized styrene–butadiene–styrene triblock copolymer and its use as compatibilizer for blending of styrene–butadiene–styrene and chlorosulfonated polyethylene

A novel method for the preparation of a quaternary ammonium ionomer of styrene–butadiene–styrene triblock copolymer (SBS) was developed by a ring‐opening reaction of epoxidized SBS with triethylamine hydrochloride in the presence of a phase transfer catalyst. The optimum conditions were studied. The ionomer was characterized by quantitative analysis, IR spectroscopy, and ¹H‐NMR spectroscopy. Its water absorbency, oil absorbency, dilute solution viscosity, and use as a compatibilizer for the blending of SBS and chlorosulfonated polyethylene (CSPE) were investigated. The results showed that, under optimum conditions, the epoxy groups can be completely converted to the quaternary ammonium groups. The IR spectrum did not exhibit the absorption peak for quaternary ammonium groups, whereas the ¹H‐NMR spectrum and titration method demonstrated it. With increasing ionic group content, the water absorbency of the ionomer increased whereas its oil absorbency decreased. These indicated the amphiphilic character of the SBS ionomer. The dilute solution viscosity of the ionomer in toluene/methanol (9/1) solvent increased with increasing quaternary ammonium group content. The ionomer was used as a compatibilizer for the blends of SBS and CSPE. The addition of a small amount of the ionomer to the blend enhanced the mechanical properties of the blends: 2 wt % ionomer based on the blend increased the tensile strength and ultimate elongation of the blend nearly 2 times. The blends of equal parts SBS and CSPE behaved as oil‐resistant thermoplastic elastomers. © 2005 Wiley Periodicals, Inc. J Appl Polym Sci 99: 1975–1980, 2006     

Al2O3—Si3N4—ZrO2多相复合材料在燃煤MHD发电中的应用

采用Ａｌ２Ｏ３基料，添加第二相（ＺｒＯ２，Ｓｉ３Ｎ４）和纤维相（ＺｒＯ２，（ｆ），以热压法制成Ａｌ２Ｏ３－Ｓｉ３Ｎ４－ＺｒＯ２多相复合材料。研究表明，新材料在青静态和动态试验中表现出良好的综合性能：１０７３Ｋ时的高温电阴率ｐ＝１．２４×１７＾７Ω．ｃｍ；静态熔渣最大腐蚀速率Ｖｓ＝０．１６μｍ／ｈ；动态最大腐蚀速率Ｖｄ＝０．４４９μｍ／ｈ。与Ａｌ２Ｏ３陶瓷相比，室温抗弯强度提高９３％，抗热震临界...     

含油切削液废水的处理和回用

采用CAF涡凹气浮和流砂过滤二级组合系统，对玉柴机器柴油废水进行了处理回用的应用研究．出水达到GB8978-1996中的一级排放标准。在进水平均COD浓度为6510mg／L，石油类浓度为9321mg／L，出水COD浓度可以降到68～91mg／L，石油类浓度可以降到1～3mg／L．处理成本低，每处理1m^3污水的综合运行成本为0.23元，每回用1m^3中水，需另增加费用开支0．22元。     

SPE-快速分离柱HPLC法测定枸杞样品中的类胡萝卜素

研究了固相萃取(SPE)富集和预分离,快速分离柱高效液相色谱(HPLC)快速测定枸杞样品中类胡萝卜素的新方法;枸杞样品中的类胡萝卜素用W aters Sep-Pak C18固相萃取小柱预分离,然后以ZORBAX Stab leBound(4.6 mm×50 mm,1.8μm)快速分离柱为固定相,甲醇-四氢呋喃为流动相分离,V(甲醇)∶V(四氢呋喃)=80∶20,用二极管矩阵检测器检测,检测波长为450 nm,枸杞样品中的几种类胡萝卜素在5 m in内可达到基线分离,比常规方法节约时间75%左右。方法标准回收率为95%~103%,RSD为1.9%~2.6%。     

几种机器学习方法在黑色素瘤计算机辅助诊断中的性能比较

黑色素瘤的计算机辅助诊断是基于激光共聚焦扫描显微镜（CLSM）皮肤图像纹理特征, 并引入机器学习的技术, 为临床应用研发的一种能够准确、有效地识别在体恶性黑色素瘤新医学诊断方法, 将常用的基于机器学习的ID3、分类与回归树（CART）和AdaBoost三种算法应用于良恶性黑色素瘤图像的特征识别, 并对各种学习方法的性能进行比较。实验结果表明, AdaBoost算法具有较好的分类识别性能, 不但提高了恶性黑色素瘤早期诊断的准确度, 降低了良性黑色素瘤的误诊率, 而且为临床上早期发现和诊断提供了客观依据。     

自适应改进和声—单纯形进化算法研究

针对和声搜索算法的不足,提出了一种自适应改进和声—单纯形进化算法(AIHSEA)。通过在新算法中加入变异策略对和声微调进行改进来增强算法的鲁棒性;适时执行单纯形算子增加群体搜索的方向性来加快搜索;采用自适应参数HMCR、PAR和BW调节全局和局部搜索。采用六个标准的优化算法测试函数对AIHSEA进行测试,并与HS、IHS和GHS算法进行对比,仿真结果表明AIHSEA算法具有较强的精确寻优和跳出局部最优的能力。     

聚氯乙烯／蒙脱土复合材料的结构与性能研究

采用熔融共混法制备得到PVC／蒙脱土复合材料。通过X射线衍射和透射电镜对复合材料的结构进行了表征。研究了钠基蒙脱土和烷基季铵盐改性的有机蒙脱土对聚氯乙烯／蒙脱土复合材料的结构、加工热稳定性、光学性能、力学性能和结构流变性能的影响。     

HZSM-5型分子筛催化乙醇溶液脱水制备乙烯的工艺

以稀乙醇溶液为原料、自制分子筛HZSM-5为催化剂,催化脱水制备乙烯.考察了硅铝比、反应温度、质量空速及乙醇的质量浓度对该反应的影响,得到了较优化的反应工艺条件为:催化剂为HZSM-5(硅铝比30)分子筛,ρ(乙醇)为100~200 g/L,质量空速为2~6 h-1,反应温度为300℃.乙醇的转化率可达99%,乙烯的选择性达99%以上.