首页 | 本学科首页   官方微博 | 高级检索  
文章检索
  按 检索   检索词:      
出版年份:   被引次数:   他引次数: 提示:输入*表示无穷大
  收费全文   110篇
  免费   18篇
  国内免费   10篇
化学   123篇
力学   2篇
物理学   13篇
  2023年   3篇
  2022年   2篇
  2021年   5篇
  2020年   3篇
  2019年   7篇
  2018年   1篇
  2017年   1篇
  2016年   11篇
  2015年   10篇
  2014年   3篇
  2013年   14篇
  2012年   9篇
  2011年   9篇
  2010年   4篇
  2009年   6篇
  2008年   6篇
  2007年   4篇
  2006年   6篇
  2005年   1篇
  2004年   5篇
  2003年   7篇
  2002年   4篇
  1999年   1篇
  1997年   1篇
  1996年   3篇
  1994年   1篇
  1987年   1篇
  1986年   1篇
  1984年   9篇
排序方式: 共有138条查询结果,搜索用时 15 毫秒
1.
Polyurethane microcapsules were prepared by mini‐emulsion interfacial polymerization for encapsulation of phase‐change material (n‐docosane) for energy storage. Three steps were followed with the aim to optimize synthesis conditions of the microcapsules. First, polyurethane microcapsules based on silicone oil core as an inert template with different silicone oil/poly(ethylene glycol)/4,4′‐diphenylmethane diisocyanate wt % ratio were synthesized. The surface morphology of the capsules was analyzed by scanning electronic microscopy (SEM) and the chemical nature of the shell was monitored by Fourier transform infrared spectroscopy (FT‐IR). Capsules with the silicone oil/poly(ethylene glycol)/4,4′‐diphenylmethane diisocyanate 10/20/20 wt % ratio showed the best morphological features and shell stability with average particle size about 4 μm, and were selected for the microencapsulation of the n‐docosane. In the second stage, half of the composition of silicone oil was replaced with n‐docosane and, finally, the whole silicone oil content was replaced with docosane following the same synthetic procedure used for silicone oil containing capsules. Thermal and cycling stability of the capsules were investigated by thermal gravimetric analysis (TGA) and the phase‐change behavior was evaluated by differential scanning calorimetry (DSC).  相似文献   
2.
相变材料因为其优良的热性能,被广泛应用于纺织品、航空航天、交通运输、农业、国防、建材、太阳能系统和医疗设备等领域。近年来,开发应用新型相变材料已经成为研究热点。本文首先概括介绍了相变材料发展进程,着重介绍了有机相变材料,包括它的分类、性能和应用。详细介绍了有机相变材料在纺织行业的应用,以及对调温纺织品测试手段的研究和建立的相关数学模型的建立。  相似文献   
3.
In this study, microcapsules were prepared by solvent evaporation technique using ethyl cellulose component as wall and essential oil as core material. The synthesis of microcapsules was carried out using different oil masses. The analysis of the microcapsules was carried out using field emission scanning electron microscope (FE-SEM) and UV spectrophotometric analysis using absorption spectrophotometer. The obtained results confirm the regular spherical shape and size of the synthesized microcapsules. The qualitative and quantitative spectrophotometric analysis of the microencapsulated immortelle oil was measured at the wavelength of 265 nm. The calibration diagram was used to calculate the unknown concentrations of the microencapsulated oil. The obtained results confirm the application of the presented method as relevant for the possible determination of microencapsulated oil on textile materials.  相似文献   
4.
廖科超  路福绥  刘村平  夏慧 《应用化学》2014,31(9):1037-1043
以丁烯氟虫腈为囊芯化合物,带有相反电性的壳聚糖和海藻酸钠为囊壁材料,采用层层自组装技术制备了丁烯氟虫腈微胶囊,通过流点法筛选出十二烷基苯磺酸钠为丁烯氟虫腈的分散稳定剂。对制备的微胶囊进行了表征,系统研究了丁烯氟虫腈微胶囊的载药量、包封率、缓释性能和抗光解性能随着组装层数增加的变化规律。结果表明,组装层数为6~8层的丁烯氟虫腈微胶囊的包封率达到80%以上,达最高释放量所需要的时间为60 h,光解率降到20%以下,综合效果最好。  相似文献   
5.
6.
7.
对惯性约束聚变靶用聚合物微胶囊的制备方法进行了研究,设计了一种基于双T型结构的微通道乳化装置,用于制备稳定的双重乳液。使用玻璃毛细管作为中间相溶液的微通道,可以提高三相流速的调节范围,从而加大乳液尺寸分布范围。三相溶液密度差异小,因此乳液的同心度可以逐渐自发调整。通过调节不同的固化转速,发现在55 r/min下微球的同心度达到最佳,超过98.7%。使用扫描电镜对靶丸进行形貌和X射线能量色散谱分析表明,超临界干燥方法可以同时满足去除内部溶剂和保持靶丸结构不受破坏的要求。最终成功制得了粒径300~1000 m、壁厚20~300 m的聚丙烯腈空心微胶囊。  相似文献   
8.
A reactive template method was used to fabricate alginate‐based hydrogel microcapsules. The uniform and well‐dispersed hydrogel capsules have a high drug loading capacity. After they are coated by a folate‐linked lipid mixture on the surface, the capsules possess higher cell uptake efficiency by the molecule recognition between folate and the folate‐receptor overexpressed by the cancer cells. Moreover, in this bioconjugate, the lipid could remarkably reduce the release rate of hydrophilic doxorubicin from the hydrogel microcapsules and encapsulate the hydrophobic photosensitizer hypocrellin B. The biointerfaced capsules could be used as drug carriers for combined treatment against cancer cell proliferation in vitro; this was much more effective than chemotherapy or photodynamic therapy alone.  相似文献   
9.
Polymers synthesized from naturally derived monomers are valuable since they decrease the reliance on petroleum based feed stocks. Cashew nut shell oil (CNSL) is a side-product from processing of edible Cashew nuts of Annacardium occidentale. One of the major components of CNSL is cardanol, which is a phenol derivative having an unsaturated pentadecyl substituent in the ‘meta’ position with varying amount of unsaturation (no double bonds to three double bonds). The substituent in the meta position can also be hydrogenated to yield completely saturated hydrogenated cardanol. Cardanol can be utilized to stabilize the dispersions of oil in water and vice versa since it displays amphiphilic behavior owing to the phenolic head and the C15 aliphatic tail. Here we report the horseradish peroxidase (HRP) catalyzed polymerization of cardanol at oil water interface to obtain polycardanol microcapsules. A synthetic analogue of hydrogenated cardanol, 3-pentadecylphenol (3PDP), was also oxidatively polymerized at the oil-water interface to obtain Poly(3-pentadecylphenol) microcapsules.  相似文献   
10.
Hollow multilayer microcapsules made of aliphatic poly(urethane‐amine) (PUA) and sodium poly(styrene sulfonate) (PSS), templated on PSS‐doped CaCO3 particles, are prepared for pH‐/thermally responsive drug delivery. The electrostatic interaction and hydrogen bonding under weak‐acid conditions between aliphatic PUA and PSS contribute to the formation of multilayer microcapsules. Scanning electron microscopy (SEM) results demonstrate an obvious variation of the hollow multilayer microcapsules in response to changes in temperature and pH value. Drug‐release behaviors using DOX as a model drug demonstrate that the drug release increases on decreasing the pH value because of the interaction weakness between aliphatic PUA and PSS in acidic conditions. Moreover, the drug release is higher at 55 °C than that at 37 °C for the sake of the shrinkage of aliphatic PUA above its lower critical solution temperature (LCST).

  相似文献   

设为首页 | 免责声明 | 关于勤云 | 加入收藏

Copyright©北京勤云科技发展有限公司  京ICP备09084417号