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   10篇
  免费   0篇
  国内免费   5篇
化学   4篇
数学   1篇
物理学   8篇
无线电   2篇
  2020年   3篇
  2014年   1篇
  2013年   1篇
  2012年   1篇
  2011年   2篇
  2003年   1篇
  2001年   2篇
  1998年   1篇
  1997年   1篇
  1994年   1篇
  1993年   1篇
排序方式: 共有15条查询结果,搜索用时 922 毫秒
1.
2.
《Composite Interfaces》2013,20(4-6):447-455
Lanthanide doped sol–gel glasses are an attractive type of luminescent material which can be processed at ambient temperatures. However, it is very difficult to obtain a uniform distribution of the complexes in glass materials because of their strong tendency to cluster formation. This problem can be solved by covalently linking of lanthanide complexes to silica matrix. In our work such materials were obtained by the sol–gel method of hydrolysis and polycondensation of tetramethoxysilane with europium complexes containing trimethoxysilyl groups. For this purpose we synthesized a novel ligand — (N-3-trimethoxysilylpropyl)-N′-1,10-phenanthroline-5-yl-thiocarbamide — and corresponding complexes [Eu(tta)3phen′]Cl3 and [Eu(pta)3phen′]Cl3. Our approach enabled us to simplify the synthetic procedure. A number of uniform samples showing intense luminescence have been obtained and the concentration dependence of their luminescence has been studied.  相似文献   
3.
研究非欧流形SOL 空间上共形平均曲率方程的可解性,通过研究轮廓曲线对具有平均曲率的旋转曲面进行分类。当这些旋转曲面的平均曲率为给定函数时,计算出相应轮廓曲线的微分方程。通过求解这些微分方程,给出旋转函数是其上共形平均曲率的充分条件。  相似文献   
4.
Reducing the ICRH (ion cyclotron range frequency) antenna-plasma interaction is one of the key points for reaching very long tokamak discharges. One problem which limits such discharges, is the appearance of hot spots on the surface of the antenna: Radio Frequency (RF) sheaths modify the properties of the edge plasma by rectifying the RF potential along open magnetic field lines and can induce hot spots. This paper investigates the corrections to sheath potentials introduced by the interactions between adjacent flux tubes. Our theoretical study started from an oscillating double Langmuir probe model, in which a transverse influx of current was included. This model was confronted with 1D PIC simulations along a magnetic field line, and demonstrated that current exchanges can decrease mean potentials. A 2D electrostatic fluid code was then developed, which couples adjacent flux tubes in a poloidal cross section with collisional conductivity or polarization currents. It showed that transverse currents are able to smooth structures smaller than a characteristic size in the sheath potential maps (results for Tore Supra). These computed rectified potentials can be used to obtain the DC electric fields in front of the antenna. And then, it gives an estimate of the particle drift and the energy flux on the antenna structure, which can explain hot spots.  相似文献   
5.
张苗  竺士炀 《物理》1997,26(3):155-159
SOI(Silicon-on-Insulator)技术被认为是21世纪的硅集成电路技术,近年来,国际上出现了一种引人注目的SOI制备新技术-智能剥离(Smartcut)技术,它的出现为解决SOI技术中质量与价格的矛盾带来了新的希望,将会有力地堆动SOI技术的进一步发展,文章简要回顾了目前存在的几种SOI制备技术,并结合我们的工作重点介绍了智能剥离这种有竞争力的SOI制备新技术。  相似文献   
6.
CoFe2-xMnxO4纳米晶薄膜的结构、磁性及磁光效应研究   总被引:1,自引:0,他引:1  
为了改善磁光材料CoFe2O4的磁学特性,本研究利用改进的溶胶-凝胶法在单晶硅衬底上制备了不同掺杂量的CoFe2-xMnxO4(x=0~2,0)纳米晶薄膜系列样品。并对其结构、磁性及磁光效应进行了研究。结果表明,Mn^3+的掺入可以有效地控制和降低CoFe2O4的居里温度,并可显著地增强薄膜的磁光效应。  相似文献   
7.
溶胶—凝胶法制备BST铁电薄膜及性能研究   总被引:5,自引:0,他引:5  
研究了一种以水为溶剂的(Ba  相似文献   
8.
表面吸附质对银亚胶体吸光特性的影响   总被引:5,自引:0,他引:5  
纯银溶胶在390nm处有一吸收峰。当银溶胶吸附了1-苯基-5-巯基四氮唑(PMT)或2-巯基苯骈噻唑(MBT)时, 银溶胶由亮黄色转变为橙红色, 即在510~550nm处出现一个新的吸收峰。研究发现, 卤素离子在银溶胶颗粒上与PMT和MBT有竞争吸附作用。但是卤离子对银溶胶的光谱吸收的影响完全不同于PMT和MBT。在讨论这种差别时应首先考虑金属银溶胶颗粒表面性质因吸附不同物质所产生的变化。  相似文献   
9.
GRILLIX employs the flux-coordinate independent approach (FCI), which allows us to study boundary plasma turbulence in realistic diverted configurations. Recently, the physical model in GRILLIX has been extended to a global drift-reduced Braginskii model, without any separation between background and fluctuations. It includes electromagnetic and thermal dynamics with hot ions, relaxation of the Boussinesq approximation and non-linear parametric dependencies. This contribution presents solutions to associated issues, that is, the ion diamagnetic polarization and the stiff parallel heat conduction. Simulations based on parameters characteristic for the Alcator C-Mod tokamak were carried out. In circular geometry, the self-consistent electric field contains zonal flows and geodesic acoustic modes in the confined region. In the scrape-off layer, the electron parallel heat conduction and its boundary condition determine the temperature and electric field, leading to sheared flows at the last closed flux surface.  相似文献   
10.
The characterization and authentication of fats and oils is a subject of great importance for market and health aspects. Identification and quantification of triacylglycerols in fats and oils can be excellent tools for detecting changes in their composition due to the mixtures of these products. Most of the triacylglycerol species present in either fats or oils could be analyzed and identified by chromatographic methods. However, the natural variability of these samples and the possible presence of adulterants require the application of chemometric pattern recognition methods to facilitate the interpretation of the obtained data. In view of the growing interest in this topic, this paper reviews the literature of the application of exploratory and unsupervised/supervised chemometric methods on chromatographic data, using triacylglycerol composition for the characterization and authentication of several foodstuffs such as olive oil, vegetable oils, animal fats, fish oils, milk and dairy products, cocoa and coffee.  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