聚醚型聚氨酯的氢键、微相分离及性能

用本体一步法合成了5种不同硬段含量(11.0％～46.9％)的二苯甲烷-4,4′-二异氰酸酯/环氧乙烷封端型聚环氧丙烷聚醚/乙二醇的聚醚型聚氨酯,并借助于IR,DSC,DMS和材料试验机等手段对该聚氨酯的氢键、微相分离及力学性能进行了表征。结果表明:随着硬段含量的增加,其>NH与微区中的>C=O的氢键化程度逐渐提高,软段微区中—O—的氢键化程度逐渐降低;微相分离程度逐渐提高;拉伸强度及硬度随之增加,扯断伸长率在硬段含量40％左右出现极大值。     

Thermal properties measurements of renatured gelatin using conventional and temperature modulated differential scanning calorimetry

The thermal properties of amorphous gelatin films and gelatin films with renatured structural order were measured by using conventional and temperature modulated differential scanning calorimetry (DSC). Different amounts of gelatin structural order associated with a melting enthalpic change in the DSC measurement were prepared based on different gelatin drying conditions. Two consecutive heating and cooling DSC measurements on the gelatin films showed that there was no change in the glass‐transition temperature (T_g) for the amorphous gelatin but there was a decrease in the T_g for the structural gelatin on the second DSC scan. This decrease was attributed to the plasticizing effect from the release of originally hydrogen‐bonded water associated with the structural gelatin. In addition, a reversing endotherm observed upon melting of the structural gelatin during a temperature modulated DSC measurement indicated that the transition of bound water to free water occurred as the partial triple‐helix gelatin melted. © 2005 Wiley Periodicals, Inc. J Appl Polym Sci 99: 1795–1801, 2006     

重防腐涂料在冶金行业的应用

阐述了涂料的防腐蚀机理，并结合冶金企业设备防腐蚀应用实例，介绍了两种新型防腐蚀涂料。     

循环流化床中流动结构的动态变化

采用激光相位多普勒粒子分析仪（ＰＤＰＡ）测量了二维循环流化床中局部颗粒运动行为及流动结构．通过将ＰＤＰＡ采集的数据进行动态图形化处理，研究了稀、密相的结构以及颗粒聚团的形成和分解．研究结果表明：在循环流化床中不仅存在稀、密两相的不均匀流动结构，而且密相和稀相自身内部也存在不均匀性；颗粒聚团的形成和分解是一个动态过程，颗粒间不同速度造成颗粒相互碰撞，密相能够分解形成稀相，稀相能够合并成为密相．在流动过程中稀相、密相及介于稀、密相间的乳相以动态的形式存在和分解，形成复杂的动态流动结构．     

RF sputter deposition of poly(tetrafluoroethylene) films as masking materials for silicon micromachining

Polymers have been studied extensively because of their wonderful array of properties. Their properties can be tailored by many means and can be made useful in many ways. Polymers can be crosslinked or branched and can provide different properties, such as conduction and passivation. This study dealt with the RF sputter deposition of poly(tetrafluoroethylene) (PTFE) films with the aim of using them as masking materials during the fabrication of various micromachined structures. The films were deposited on silicon substrates at different plasma powers (100, 150, and 200 W) for a constant deposition time (60 min). To test the masking properties, the deposited films were immersed in a 20 wt % aqueous KOH solution at 80°C for 60 min. The films showed lower contact angles and interfacial tension, and this indicated good adhesion of the films to the silicon substrates. Good adhesion is an essential quality of masking materials during micromachining. The structural properties of the as‐deposited and etched films were studied with Fourier transform infrared and X‐ray photoelectron spectroscopy. These indicated that the bonding groups and binding energies of C? F and C? CF matched the reported values well. Furthermore, the presence of C? F and C? CF bonds, even after the etching of silicon substrates in highly alkaline KOH solutions for 60 min, showed that the PTFE films remained unchanged in the etchant and, therefore, could function as good masking materials during the fabrication of micromachined structures. © 2003 Wiley Periodicals, Inc. J Appl Polym Sci 91: 1183–1192, 2004     

2,2￠,6,6￠-四甲基-4,4￠-二苯氧基二苯砜、二苯醚和对苯二甲酰氯三元无规共聚物的合成与表征

以2,2￠,6,6￠-四甲基-4,4￠-二苯氧基二苯砜(o-M2DPODPS)、二苯醚(DPE)和对苯二甲酰氯(TPC)为单体，在无水AlCl3和N,N-二甲基甲酰胺(DMF)存在的条件下，于1,2-二氯乙烷(DCE)中进行低温溶液无规共缩聚，合成了一系列新型线型高分子量含双邻甲基取代结构的聚醚砜醚酮酮(DM-PESEKK)/聚醚酮酮(PEKK)无规共聚物，并用IR, DSC, XRD, TGA和1H-NMR等方法对共聚物进行了表征分析，考察了共聚物的溶解性能. 结果表明，随着DM-PESEKK含量的增加，玻璃化转变温度(Tg)逐渐升高，熔融温度(Tm)逐渐降低，结晶度下降，溶解性得到明显改善.     

渣油加氢催化剂孔结构对反应活性的影响

在3L中型加氢试验装置上考察了渣油加氢脱硫催化剂孔结构对反应活性的影响，试验结果表明，当孔结构发生变化时，催化剂的脱硫、脱氮、脱残炭及脱金属反应活性呈现不同的变化规律。     

多壁纳米碳管的超声短切处理

采用超声方法对多壁纳米碳管进行短切处理，比较系统地考察了超声时间对纳米碳管的长度、孔结构和形貌的影响。结果表明，超声粉碎可以有效地短切多壁纳米碳管，随超声时间的延长，纳米碳管的长度显著减小。在超声处理120min后，纳米碳管被短切到平均长度为400nm。超声短切后的纳米碳管比表面积和孔容均显著增加。进一步延长超声时间，其比表面积和孔容反而下降。     

水性聚氨酯/丙烯酸酯复合乳液的合成及其性能研究

通过自由基乳液聚合,合成具有核壳结构的水性聚氨酯/丙烯酸酯复合乳液(PUA)。用IR、DSC和TEM对产物结构进行了表征,证明水性聚氨酯(PU)与丙烯酸酯单体在实验条件下发生了共聚反应;考察了PVA乳液及其胶膜耐热性和耐溶剂性。结果表明具有核壳结构的PUA乳液的各项性能均比水性聚氨酯有明显提高。     

Progressive events in supervisory control and compositional verification

This paper investigates some limitations of the nonblocking property when used for supervisor synthesis in discrete event systems. It is shown that there are cases where synthesis with the nonblocking property gives undesired results. To address such cases, the paper introduces progressive events as a means to specify more precisely how a synthesised supervisor should complete its tasks. The nonblocking property is modified to take progressive events into account, and appropriate methods for verification and synthesis are proposed. Experiments show that progressive events can be used in the analysis of industrial-scale systems, and can expose issues that remain undetected by standard nonblocking verification.