SEBS-g-MAH对PC/PBT共混物性能影响

利用双螺杆挤出机制备聚碳酸酯(PC)/聚对苯二甲酸丁二醇酯(PBT)/马来酸酐接枝氢化苯乙烯-丁二烯-苯乙烯共聚物(SEBS-g-MAH)的共混物.通过扫描电子显微镜(SEM)、平板流变仪研究了SEBS-g-MAH对PC/PBT共混物的机械性能、断面形态结构、动态力学行为的影响.结果表明:SEBS-g-MAH提高了PC/PBT共混物的相容性,随着SEBS-g-MAH用量的增加,共混物的缺口冲击强度和断裂伸长率上升,拉伸强度和弯曲强度下降.当SEBS-g-MAH质量分数为5%时共混物的综合性能最佳,同时,SEBS-g-MAH的加入.并未对PC/PBT共混物的成型加工性能产生不良影响.     

介孔TiO2晶须及其担载RuO2的电容性能

烧结法制备的介孔TiO₂晶须具有高结晶度,孔径可控,并且制备成本低,可以大规模生产。如能将该材料用于电化学电容器电极材料,则可以降低成本、提高电容器性能。采用孔径分布在10 nm左右的介孔TiO₂晶须及其担载氧化钌的材料制备了电极,循环伏安法分析表明该材料在中性的0.1 mol·L^-1的Na₂SO₄溶液中即具有典型的电容行为,并且在较宽的扫描范围表现出一定的电容特性;介孔TiO2晶须担载RuO₂后,其电容性能优异,比电容达到940.4 F·g ^_-1（以RuO₂质量计）,有可能作为电化学电容器的低成本大规模生产的电极材料。     

Microstructural Evolution of 6061 Aluminum Gas-Atomized Powder and High-Pressure Cold-Sprayed Deposition

Gas-atomized 6061 aluminum powder was used as feedstock for deposition using a high pressure cold-spraying process. The microstructures of the as-received powder and cold spray processed (CSP) ultrafine-grained (UFG) 6061 depositions were characterized by different electron microscopy techniques. It was found that there is segregation of solute elements at the particle grain boundaries, which is increased after cold spraying (CS). Various microstructural features were observed in both directions (parallel and perpendicular) of the CSP layer, including low-angle grain boundaries, clustered-small-cell walls, and dislocation tangle zones. The results also indicated that a combination of different recrystallization mechanisms (i.e., continuous and geometrical) may contribute to the formation of nano and UFG structures during CS.     

The functional effectiveness of reprocessed rice bran as an ingredient in bakery products

Rice bran, as a coproduct of the rice milling industry, is yet to be efficiently utilized for human consumption. Despite its excellent nutrition, its hypoallergenicity and recently claimed nutraceutical properties, it is mainly utilized for animal feed or simply discharged. It is of interest to incorporate this healthy ingredient back into our diet. In these studies, rice bran was processed by drum-drying and pin-milling. This processing step increased hydration capacity and removed grittiness by decreasing mean particle size from 444 to 72 microns and producing a desirable monomodal size distribution. There are no reported studies addressing differences in rice bran composition in food applications and specifically their effect on bread quality. Thus, we were interested in examining the functional properties of bread made with processed full-fat (FFRB) and defatted (DFRB) bran from three cultivars (long, medium and short grain rice) and to compare them to a control. For 10% and 20% replacements of wheat flour, respectively, loaf volume increased 2% for FFRB and decreased 6% for DFRB and decreased by 6% for FFRB and 17% for DFRB. Loaf volume was highest with medium rice bran and this was attributed to its lowest fiber content and highest starch content among three varieties. Texture profile analysis showed no significant differences as far as cohesiveness and springiness, but bread hardness, gumminess and chewiness increased with increased levels of rice bran and was higher for DFRB bread than for FFRB. Measurements of texture determined that there was no detrimental effect in adding 10% FFRB to the bread and a very slight hardening of the loaves with the 20% FFRB, when compared to the control. It was found that FFRB gave better textural characteristics than DFRB overall and differences amongst different rice bran varieties were not significant.     

宗教影响下的中西方 古代建筑的空间组织方式

空间组织方式是建筑物受宗教影响较突出的方面,中西方古代建筑截然不同的空间组织方式,从形成到成为一个完善的体系,都留下了宗法社会宗教思想介入的烙印。     

斜纹夜蛾核多角体病毒郴州株的形态学、基因组酶切图谱及生物活性测定

对斜纹夜蛾核多角体病毒(SpliNPV)郴州株的多角体形态进行了扫描电镜观察,多角体直径在1.5～2.5μm之间;多角体经切片后透射电镜观察,每个病毒囊膜内包被的核衣壳数为2～7个;提取SpliNPV郴州株和广州株的基因组进行限制性内切酶分析,两者的图谱比较近似;分别以不同浓度的两株SpliNPV病毒悬液感染3龄初斜纹夜蛾幼虫,其半致死浓度分别为1.8×106 OBs/mL和4.2×106 OBs/mL,两者在统计学上没有显著差异。     

UML在运输业务管理系统建模中的应用

以运输业务管理系统项目的开发为背景,探讨了UML在运输业务管理系统建模中的应用问题。在对系统进行需求分析的基础上,采用ROSE构建了系统的用户需求模型、对象结构模型、行为模型和实现模型。     

基于蒙特卡罗模拟的快速剂量计算方法研究

本文应用蒙特卡罗算法建立了一个光子虚拟源模型，用于模拟计算任意形状和强度的外照射放射治疗的射束分布。建立的源模型包含一个由方形网格元素组成的光子通量矩阵，定位于距离加速器靶下方20cm处。通过使用蒙特卡罗模拟代码包BEAMnre，模拟粒子加速器治疗头各部件中的传输过程，获得源模型所在平面的光子通量和能谱分布，并进行重构，以反映物理射束经过加速器射束成形部件后所引起的形状改变。通过比较6MV光子柬3个标准方野的深度剂量和离轴比分布的计算结果和测量结果，取得了较好的吻合。通过对不规则野剂量分布的计算和测量结果的等剂量线进行比较，在90％和50％等剂量区吻合较好，在10％低剂量区稍有差异。本文提出的光子虚拟源模型能够较为精确地模拟计算任意形状和强度的外照射放射治疗射束分布。     

Monitoring agricultural soil moisture extremes in Canada using passive microwave remote sensing

Current methods to assess soil moisture extremes rely primarily on point-based in situ meteorological stations which typically provide precipitation and temperature rather than direct measurements of soil moisture. Microwave remote sensing offers the possibility of quantifying surface soil moisture conditions over large spatial extents. Capturing soil moisture anomalies normally requires a long temporal record of data, which most operating satellites do not have. This research examines the use of surface soil moisture from the AMSR-E passive microwave satellite to derive surface soil moisture anomalies by exploiting spatial resolution to compensate for the shorter temporal record of the satellite sensor. Four methods were used to spatially aggregate information to develop a surface soil moisture anomaly (SMA). Two of these methods used soil survey and climatological zones to define regions of homogeneity, based on the Soil Landscapes of Canada (SLC) and the EcoDistrict nested hierarchy. The second two methods (ObShp3 and ObShp5) used zones defined by a data driven segmentation of the satellite soil moisture data. The level of sensitivity of the calculated SMA decreased as the number of pixels used in the spatial aggregation increased, with the average error reducing to less than 5% when more than 15 pixels are used. All methods of spatial aggregation showed somewhat weak but consistent relationship to in situ soil moisture anomalies and meteorological drought indices. The size of the regions used for aggregation was more important than the method used to create the regions. Based on the error and the relationship to the in situ and ancillary data sets, the EcoDistrict or ObShp3 scale appears to provide the lowest error in calculating the SMA baseline. This research demonstrates that the use of spatial aggregation can provide useful information on soil moisture anomalies where satellite records of data are temporally short.