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选用液体石蜡为油相,油酸钠和十六烷基三甲基溴化铵(CTAB)作为乳化剂,利用高速搅拌和超声乳化的方法制备了一种新型液体石蜡乳液作为冰浆蓄冷介质。电导率测试表明:该乳液为O/W型,乳液的D50粒径为1.56μm。在乳液中添加乙醇和丁醇可有效抑制冰浆粘附聚甲基戊烯(PMP)、玻璃和不锈钢烧杯壁面。乳液在解除过冷后的初期,冰浆在不锈钢烧杯中形成速度最快,在PMP烧杯中形成速度最慢。在解除过冷相同时间内,添加乙醇的乳液体系蓄冰率(IPF)比添加丁醇的高,但随着结晶时间的增加,差值逐渐减小。解除过冷3 h后冰粒呈颗粒状,IPF在55%~65%之间,具有良好的流动分散性。 相似文献
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以粗碘和硫酸铜为原料,水合肼为还原剂,利用微乳液法合成了六边形薄片状γ-CuI晶体.采用XRD和SEM手段研究了微乳液工艺技术条件对合成γ-CuI晶相组成和微观形貌的影响.结果表明,表面活性剂CTAB用量、水含量和反应物浓度对微乳液法制备的γ-CuI晶相组成和晶体形状没有太大影响,但对晶体尺寸具有较大影响.适宜的微乳液制备工艺条件能产生适当的界面膜强度,有效控制碘化压铜晶体尺寸.CTAB-正戊醇-环己烷-水体积比为3∶3∶7∶10,硫酸铜溶液0.1mol/L和碘化铵溶液0.2mol/L,常温下500r/min搅拌2h合成产物为六边形薄片状γ-CuI. 相似文献
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采用W/O型微乳液法制备出了CNTs/PbO和CNTs/CuO,利用电导率仪测量体系的溶水量,通过绘制三元相图研究了微乳液组成的表面活性剂和助表面活性剂的配比、温度以及盐的浓度等因素对W/O型微乳液相区的影响。分析得出最佳微乳液体系环己烷和活性剂的比为4 6,表面活性剂和助表面活性剂的比为2 3,反应温度为25℃。根据推进剂的成分,将一定量的燃烧催化剂和黑索今混合,通过热分析表征CNTs/PbO、CNTs/CuO对黑索今的催化热分解。结果表明,新的催化剂明显加快黑索今的热分解,分解峰位降低16.07℃。 相似文献
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目的 设计一种包埋手段,最大限度地提高番茄红素的稳定性,延缓番茄红素降解速率,从而扩大番茄红素的应用。方法 以番茄红素晶体为目标芯材,利用伪三元相图获得番茄红素微乳液的最佳配方。利用光降解和热降解动力学模型,探究番茄红素晶体包埋前后的光、热稳定性。结果 制备番茄红素微乳液的最佳配方:油相为乙酸乙酯,表面活性剂为吐温60,助表面活性剂为无水乙醇,表面活性剂与助表面活性剂之比(Km)为2∶1,此时形成的微乳面积最大为53.05%。番茄红素微乳液中番茄红素的质量浓度为352.90μg/mL,平均粒径为13.22 nm,聚合物分散性指数(PDI)为0.054 8,其构相为O/W型微乳液。制备的番茄红素微乳液具有良好离心稳定性和贮藏稳定性。在不同光照时间和温度处理下,其降解均符合一级降解动力学规律,且微乳中番茄红素降解速率小于番茄红素晶体降解速率。结论 番茄红素被微乳液包埋后提高了水溶性、稳定性,同时能够有效延缓番茄红素晶体的光降解和热降解速率,对番茄红素起到保护作用。 相似文献
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相变材料的过冷在蓄热方面一直被认为是一大缺点,但是使材料处于长期、稳定的过冷状态,可以使季节性储热成为可能。为了保持稳定高效的内能,保持储热材料过冷的稳定是一个重要的前提。采用三水醋酸钠作为储热介质,加入不同比例的去离子水形成盐水质量比不同的混合体系,研究其在不同冷却速度和冷却温度条件下溶液过冷的稳定情况及多次循环后的过冷度。结果表明,冷却速度越快、冷却温度越低,溶液的过冷稳定性越差;溶液中含水比例越高,其过冷的稳定性越好但相变温度越低。经过100次循环后,在-20℃的冷却环境中,混合体系过冷度降低约10℃,在0℃以上依旧保持稳定过冷。差示扫描量热分析表明,盐水质量比为3∶3的三水醋酸钠混合体系的平均相变潜热值最高,为291.6kJ/kg。与商用热袋相比,盐水质量比为3∶3的三水醋酸钠混合体系具有更高潜热值和相变温度并有更好的过冷稳定性,具有较大应用潜力。 相似文献
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包覆表面活性剂的TiO2电流变液 总被引:8,自引:0,他引:8
利用W/O微乳液法,分别由水/SPan80或DBS/正戊醇/环己烷形成W/O微乳液,将钛醇盐在微乳中以水核为中心水解,制得包覆表面活性剂的TiO2粒子,包覆表面活性剂可显著提高TiO2的电流变活性,且非离子型表面活性剂的效果远好于离子型表面活性剂,一种典型的颗粒/硅油体积比为31%的电流变液在3kV/mm直流电场下的剪切 应力为1.4KPa,约为纯TiO2的3倍,漏电流密度小于25uA./cm2,当Span80与TiO2的质量比为7-13%,时有最佳电流变效应,包覆适量的非郭子表面活性剂明显优化电流变液的温度效应,改善颗粒的悬浮稳定性。 相似文献
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Masao Doyama 《Bulletin of Materials Science》1999,22(3):723-728
By making a step on one surface (
) of a rectangular small paralellepiped copper crystal, dislocations could be created by the molecular dynamic method. The
dislocation created was not a complete edge dislocation but a pair of Heidenreich-Shockley partial dislocations. Each time
a dislocation was created, the stress on the surface was released. Small copper crystals having a notch were pulled (until
fracture), compressed and buckled by use of the molecular dynamic method. An embedded atom potential was used to represent
the interaction between atoms. Dislocations were created near the tip of the notch. A very sharp yield stress was observed.
The results of high speed deformations of pure silicon small crystals using the molecular dynamics are presented. The results
suggest that plastic deformation may be possible for the silicon with a high speed deformation even at room temperature. Another
small size single crystal, the same size and the same surfaces, was compressed using molecular dynamic method. The surfaces
are {110}, {112} and {111}. The compressed direction was [111]. It was found that silicon crystals are possible to be compressed
with a high speed deformation. This may suggest that silicon may be plastically deformed with high speed deformation. 相似文献
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目的 探索江门世遗文化的传承、发展和转化的新思路,践行国家在《粤港澳大湾区发展规划》纲要中要求江门承担与港澳地区文化创意合作与开发任务的分工。方法 与澳门高校紧密合作,开展专业培训课程,以开平碉楼为例,从人文视角开展设计研究,梳理开平碉楼的文化脉络,把世遗文化的元素和其背后的文化融入文创产品中,提升文创产品的附加值,推动当地文创产业结构的变革。结果 两地高校构建了稳定的科研团队,开设长期有效的设计培训课程,与景区建立了研究协作关系,帮助景区构建了一套产销研的商业模式。结论 以跨区域高校合作为平台,以文创产品为抓手,依托江澳两地的资源优势,可以构建江门世遗文化全新的品牌形象,最终推动开平世遗文化的活化。 相似文献
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Albert C. Parr 《Journal of research of the National Institute of Standards and Technology》2001,106(1):151-186
The national measurement system for photometric and radiometric quantities is presently based upon techniques that make these quantities traceable to a high-accuracy cryogenic radiometer. The redefinition of the candela in 1979 provided the opportunity for national measurement laboratories to base their photometric measurements on optical detector technology rather than on the emission from high-temperature blackbody optical sources. The ensuing technical developments of the past 20 years, including the significant improvements in cryogenic radiometer performance, have provided the opportunity to place the fundamental maintenance of photometric quantities upon absolute detector based technology as was allowed by the 1979 redefinition. Additionally, the development of improved photodetectors has had a significant impact on the methodology in most of the radiometric measurement areas. This paper will review the status of the NIST implementation of the technical changes mandated by the 1979 redefinition of the candela and its effect upon the maintenance and dissemination of optical radiation measurements. 相似文献
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Production planning and scheduling are becoming the core of production management, which support the decision of a petrochemical company. The optimization of production planning and scheduling is attempted by every refinery because it gains additional profit and stabilizes the daily production. The optimization problem considered in industry and academic research is of different levels of realism and complexity, thus increasing the gap. Operation research with mathematical programming is a conventional approach used to address the planning and scheduling problem. Additionally, modeling the processes, objectives, and constraints and developing the optimization algorithms are significant for industry and research. This paper introduces the perspective of production planning and scheduling from the development viewpoint. 相似文献
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Miniature and MEMS-type vacuum sensors and pumps 总被引:1,自引:0,他引:1
Anna Grecka-Drzazga 《Vacuum》2009,83(12):1419-1426
In the paper, the observable trends of the actual research and development of selected types of miniature and MEMS-type vacuum sensors are presented. Some information about the new types of active vacuum gauges, which are offered by the leading manufacturers of the vacuum measurement instruments, is given. Next, the list of MEMS devices that need vacuum for proper operation is presented. Some aspects of vacuum-encapsulation of MEMS devices, on wafer level and package level are shown. The new conceptions of obtaining and maintenance of high and ultra-high vacuum in MEMS devices are described. They concern the conception of integration of a miniature orbitron pump on-chip with MEMS-type device or with vacuum part of the portable advanced instruments such as electron microscope, ion mass spectrometer, and free electron laser. 相似文献