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   2篇
  免费   6篇
  国内免费   1篇
化学   2篇
物理学   7篇
  2014年   1篇
  2013年   2篇
  2012年   1篇
  2011年   1篇
  2010年   3篇
  2009年   1篇
排序方式: 共有9条查询结果,搜索用时 15 毫秒
1
1.
李鹤  杨周  张义民  闻邦椿 《物理学报》2011,60(7):70512-070512
根据Takens定理,研究了混沌时间序列相空间重构嵌入维数的选取问题.提出了基于径向基函数神经网络预测模型性能的嵌入维数估计方法,即根据嵌入维数与混沌时间序列预测模型性能的变化关系来确定嵌入维数.通过对几种典型混沌动力学系统的数值验证,结果表明该方法能够确定出合适的相空间重构嵌入维数. 关键词: 混沌 相空间重构 嵌入维数 预测  相似文献   
2.
杨周  张文华 《催化学报》2014,35(7):983-988
正1.Introduction We have recently witnessed a breakthrough in highly effi-cient solar cells, where the organolead halide perovskite, CH3NH3PbI3, was used as an absorber of sunlight. The perov-skite was used to sensitize mesoporous TiO2 films in a solid-state mesoscopic solar cell to deliver a power conversion  相似文献   
3.
公茂刚  许小亮  杨周  刘艳松  刘玲 《中国物理 B》2010,19(5):56701-056701
ZnO micro/nano complex structure films,including reticulate papillary nodes,petal-like and flake-hole,have been self-assembled by a hydrothermal technique at different temperatures without metal catalysts.The wettability of the above film surfaces was modified with a simple coating of heptadecafluorodecyltrimethoxy-silane in toluene.After modifying,the surface of ZnO film grown at 50 C was converted from superhydrophilic with a water contact angle lower than 5 to superhydrophobic with a water contact angle of 165.Additionally,the surface of reticulate papillary nodes ZnO film grown at 100 C had excellent superhydrophobicity,with a water contact angle of 173 and a sliding angle lower than 2.Furthermore,the water contact angle on the surface of petal-like and flake-hole ZnO films grown at 150 C and 200 C were found to be 140 and 120,respectively.The wettability for the samples was found to depend strongly on the surface morphology which results from the growth temperature.  相似文献   
4.
合成钯-四氧化三铁纳米粒子(Pd-Fe3O4NPs)并制备了乙酰胆碱酯酶(AChE)电流型生物传感器用于检测有机磷杀虫剂。Pd-Fe3O4NPs在电极与乙酰胆碱酯酶之间提供了一个具有较高电子传导性、较好生物相容性和较强催化活性的微环境,有效地提高了乙酰胆碱酯酶的生物活性和有机磷杀虫剂对乙酰胆碱酯酶的抑制作用。以对硫磷为有机磷杀虫剂模型分子,乙酰胆碱酶的抑制率与对硫磷浓度在5×10-12~1×10-9mol/L之间呈现良好的线性关系,检测限为2.5×10-12mol/L。  相似文献   
5.
马恺  李华  张晗  许小亮  公茂刚  杨周 《中国物理 B》2009,18(5):1942-1946
<正>The hydrophobicity of the lotus leaf is mainly due to its surface micro—nano composite structure.In order to mimic the lotus structure,ZnO micro-nano composite hydrophobic films were prepared via the three-step method.On thin buffer films of SiO2,which were first fabricated on glass substrates by the sol—gel dip-coating method,a ZnO seed layer was deposited via RF magnetron sputtering.Then two different ZnO films,micro-nano and micro-only flowerlike structures,were grown by the hydrothermal method.The prepared films have different hydrophobic properties after surface modification.The structures of the obtained ZnO films were characterized using x-ray diffraction and field-emission scanning electron microscopy.A conclusion that a micro-nano composite structure is more beneficial to hydrophobicity than a micro-only structure was obtained through research into the effect of structure on hydrophobic properties.  相似文献   
6.
一款超薄800万像素手机镜头的设计   总被引:1,自引:0,他引:1  
杨周  阳慧明  丁桂林 《应用光学》2013,34(3):413-419
 为了满足市场对超薄手机镜头的要求,运用光学软件CODEV,结合非球面理论,设计一款新的超薄800万像素手机镜头。该镜头由4片非球面塑料镜片,1片滤光镜片和1片保护玻璃组成,其中第1片透镜是正透镜,第2片镜片是负透镜,第3片镜片是正透镜,第4片镜片是负透镜,且光阑位于第1片透镜的前面。镜头光圈值F为2.4,视场角2ω为65.5°,焦距为3.731 5 mm,后焦距0.31 mm,镜头总长度为4.6 mm,在最高频率1/2处大多数视场的MTF值均大于0.5,畸变小于2% 。  相似文献   
7.
The elementary beam model is modified to include the surface effects and used to analyze the deflections of nanowires under different boundary conditions. Tile results show that compared to deflections of nanowires without consideration of surface effects, the surface effects can enlarge or reduce deflections of nanowires, and nanowire buckling occurs under certain conditions. This study might be helpful for design of nanowire-based nanoelectromechanical systems.  相似文献   
8.
<正>A superhydrophobic aluminum sheet is fabricated via a hot water immersing process and subsequently surface modification with heptadecafluorodecyltrimethoxy-silane(HTMS).As revealed by the scan electron microscopy(SEM), X-ray diffraction(XRD),and Fourier-transform infrared spectrophotometer(FTIR) results,a rough pseudoboehmite film is formed on the aluminum sheet,and HTMS molecules are grafted on the film surface successfully.These two factors make the treated aluminum sheet present superhydrophobicity with a water contact angle larger than 160°and sliding angle less than 5°,and possess a self-cleaning property.Furthermore,the flexible superhydrophobic aluminum sheet could be pasted to a cylinder surface without destroying its superhydrophobicity.At the end,the effect of hot water treatment time on superhydrophobicity is investigated.  相似文献   
9.
杨周  许小亮  公茂刚  刘玲  刘艳松 《中国物理 B》2010,19(12):126103-126103
This paper reports that the film composed of flower-like ZnO micro-spheres,which consists of nano-sheets,is fabricated by chemical bath deposition.By adding hydrogen fluoride(HF) into the reaction solution,which contains zinc nitrate hexahydrate and hexamethylenetetramine,the ZnO crystal growth process is changed and the film composed by ZnO micro-spheres is obtained after keeping the reaction solution at 95 C for 2 h.The morphology,crystal phase and wettability of the sample are characterized by scanning electron microscope,x-ray diffraction and contact angle meter,respectively.The results show that the film has the micro-nano compound structure.After modification with heptadecafluorodecyltrimethoxy-silane,the wettability of the film changed from superhydrophilicity to superhydrophobicity,on which water contact angle and the sliding angle are 154 and less than 5 for 8-μL water droplet,respectively.Additionally,the formation mechanism of the ZnO micro-sphere is also discussed.  相似文献   
1
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