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排序方式: 共有774条查询结果,搜索用时 31 毫秒
1.
A stochastic approximation algorithm for estimating multichannel coefficients is proposed, and the estimate is proved to converge to the true parameters a.s. up-to a constant scaling factor. The estimate is updated after receiving each new observation, so the output data need not be collected in advance. The input signal is allowed to be dependent and the observation is allowed to be corrupted by noise, but no noise statistics are used in the estimation algorithm. 相似文献
2.
Sadaharu Jo 《Applied Surface Science》2006,252(10):3514-3519
The morphologies and lattice structures of anthracene single crystals grown from the vapor phase were investigated using optical microscopy, phase contrast microscopy, atomic force microscopy (AFM), and X-ray diffraction analysis. Common morphologies with hexagonal large planes were observed irrespective of crystal size. The observation of certain surface morphologies with a phase contrast microscopy revealed that the spiral steps originated from screw dislocations present on the (0 0 1) planes. Moreover, the center and edge of the (0 0 1) planes had large curvatures, similar to hills. Resultantly, quarter-monolayer (ML) steps were observed on the large and flat planes between both hills. 相似文献
3.
4.
The dendrite growth process of transparent NaBi(WO4)2 with small prandtl and high melting point was studied by using the in-situ observation system. According to the dynamic images and detailed information, there are two kinds of restriction effect on
the dendrite growth, the competition between arms and branches and the convection in the melt. The dendrite growth rate was
time dependent, and the rate of arm growth reached the maximum 5.8 mm/s in the diffusive-advective region and rapidly decreased
in the diffusive-convective region. The growth rate of branch had the same change trends as the arm’s. Based on the EPMA-EDS
data of solidification structure of quenched NaBi(WO4)2 melt, it was found that there were component differences from stoichiometric concentration in the melt near the interface
during the growth process.
Supported by the National Natural Science Foundation of China (Grant No. 50331040) and the Innovation Funds from Shanghai
Institute of Ceramics, Chinese Academy of Sciences (Grant No. SCX0623) 相似文献
5.
X光底片在位相对标定 总被引:3,自引:0,他引:3
本文描述了X光底片在位相对标定技术。其原理是使X射线谱经阶梯形吸收滤片透射后,对X光底片曝光,测量底片的曝光量。文中给出了标定方法和数据处理方法,而且也给出了在X光激光实验中得到的Kodak AA5底片的特性曲线。 相似文献
6.
Dynamic systems described by nonlinear differential equations of the second order are studied. It is assumed that certain
preliminary information on the dissipative or elastic characteristics of systems is known. A new approach is demonstrated
to obtaining full information on unknown or partially known characteristics of a system from measurements of not only displacements
but also velocities and accelerations
__________
Published in Prikladnaya Mekhanika, Vol. 41, No. 6, pp. 139–143, June 2005. 相似文献
7.
0IntroductionInrecentyearsgreatattentionhasbeenpaidtosupramolecularchemistryandawidevarietyofnet鄄workshavealreadybeenconstructedbasedupontheprincipleofcrystalengineering[1~3].Usually,variousmultifunctionalorganicligands,bothrigidandflexiblemulticarboxyli… 相似文献
8.
有机磷配位铐或钴联基配合物是生产难或醇的工业催化剂,一般公认金属氢化物是反应的催化活性物种.通常反应活性物种仅存在干反应状态下,其结构表征非常困难,在许多研究中只能关联催化剂母体与其活性的关系[‘1;而未能揭示出催化的本质,给催化剂设计造成很大困难,因而对催化剂活性物种的直接表征受到普遍关注.B。wn问、Morrista]及本文作者研究组*均采用加压原位红外光谱方法,在烯烃氢甲酸化反应条件下捕捉到HCO(CO)3L存在的信息·但用相同方法在反应条件下,在RhH键特征吸收谱带195O-2200Cm‘内未观测到错氢化物的Rh-… 相似文献
9.
P. Niedzielski M. Siepak B. Dudzińska-Huczuk 《Central European Journal of Chemistry》2003,1(3):314-324
This paper reports the results of an optimisation study for a procedure to determine the total selenium and its inorganic
species, Se(IV) and Se(VI) using atomic absorption spectrometry combined with hydride generation and in-situ trapping of the
analyte on the inner walls of the graphite tube. With the use of the proposed modification, a detection limit (3σ) of 0.018
ng/ml is achieved. This paper presents exemplary results, according to the proposed procedure, for selenium determination
in samples of marine water. The concentrations of selenium in the samples ranged from <0.02 ng/ml to 0.16ng/ml of Se(IV) and
from <0.02 ng/ml to 0.10 ng/ml of Se(VI). 相似文献
10.
以聚丙烯微孔膜为基材,通过扩散控制原位共聚合的方法在人填充了组成沿膜的厚度方向逐渐改变的无规共聚物,X-光电子能谱(XPS)、全反射红外光谱(ATR)以及动态粘弹谱的分析结果。说明所制备得到的合膜具有明显的渐变聚合物性质。 相似文献