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51.
StudyoftheLaserLightEffectonImprovingSheepSemenQuality¥YUEWenbin;LIUWenzhong(DepartmentofAnimalShanxiAgricultutalUniversity,S... 相似文献
52.
Ying?HeEmail author Wenbin?Sang Jun’an?Wang Ruofeng?Wu Jiahua?Min 《Journal of nanoparticle research》2005,7(2-3):307-311
The growth of the oriented zinc oxide (ZnO) nanorods on silicon substrates based on a simple novel chemical transformation and thermal hydrolysis by using polyvinyl alcohol (PVA) as self-assembling complex polymer was introduced in this paper. All the polymers were removed after chemical oxidation and only the carbonized grid backbones remained that confines the ZnO nanorod’s diameter and enhance the absorption and diffusion of ZnO at the tips of the nanorods during growth. The ZnO nanorods are investigated by FTIR, XRD and FE-SEM. The results indicated that these nanorods have fine hexagonal wurtzite crystal structure and their diameter varies from 20 to 90 nm and the length up to about 1 μm. A polymer-localized ZnO growth model is proposed, which well explains the growth behavior of ZnO nanorods.This revised version was published online in August 2005 with a corrected issue number. 相似文献
53.
Chiral molecular squares 1-12 based on [M(dppe)](2+) metallocorners (M = Pd or Pt, and dppe = bis(diphenylphosphino)ethane) and new angular bipyridine bridging ligands derived from the 1,1'-binaphthyl framework were readily assembled and characterized by a variety of techniques including infrared, UV-vis, circular dichroism (CD), and NMR spectroscopy, and ESI mass spectrometry. All these chiral metallocycles are highly luminescent in solution at room temperature with quantum efficiency of 0.06-0.63. Interestingly, when equal molar enantiopure molecular squares of opposite handedness were mixed in solution, a new meso dimeric metallocycle with C(2) symmetry formed. This result indicates the lability of the M-pyridyl bonds in these metallocycles, which may hinder their applications in many enantioselective processes. 相似文献
54.
On a Problem of the Theory of Multiply Local Formations 总被引:1,自引:0,他引:1
We describe the -closed n-multiply local formations
such that the lattice of all -closed n-multiply local formations between
and
is Boolean. 相似文献
55.
Summary. In this paper, we derive a posteriori error estimates for the finite element approximation of quadratic optimal control problem
governed by linear parabolic equation. We obtain a posteriori error estimates for both the state and the control approximation.
Such estimates, which are apparently not available in the literature, are an important step towards developing reliable adaptive
finite element approximation schemes for the control problem.
Received July 7, 2000 / Revised version received January 22, 2001 / Published online January 30, 2002
RID="*"
ID="*" Supported by EPSRC research grant GR/R31980 相似文献
56.
TiO2-coated activated carbon (TiO2/AC) composites and pure TiO2 powders were prepared by a sol-gel method using tetrabutylorthotitanate as a precursor. The samples were characterized by X-ray diffraction (XRD), scanning electron microscopy (SEM), differential thermal analysis (DTA), X-ray photoelectron spectrum (XPS) and nitrogen absorption. The photoactivity of samples was evaluated by methylene blue (MB) degradation. The analysis results show that compared with pure TiO2 powders, the spherical-shaped TiO2 particles are well-dispersed in the AC matrix and the size of the resulting TiO2 crystallites decreases to below 40 nm with increasing phase transformation temperature. The AC matrix creates anti-calcination effects and shows interfacial energy effects that control the growth of the TiO2 particles, baffle the anatase to rutile phase transition, and cumber the TiO2 particles to agglomerate. Compared with the surface areas of TiO2 powders, the combination of TiO2 and AC forms composites with high surface areas which are slightly affected by calcination temperature. By AC support, the photoactivity of TiO2 is increased in MB photocatalytic course, possible because active carbon increases photocatalytic activity of TiO2 particles by producing high concentration of organic compound near TiO2, and small-size TiO2 particles are well-dispersed on the surface of AC. 相似文献
57.
In this paper, adaptive finite element method is developed for the estimation of distributed parameter in elliptic equation.
Both upper and lower error bound are derived and used to improve the accuracy by appropriate mesh refinement. An efficient
preconditioned project gradient algorithm is employed to solve the nonlinear least-squares problem arising in the context
of parameter identification problem. The efficiency of our error estimators is demonstrated by some numerical experiments.
相似文献
58.
Chuande Wu Xiang Lin Rongmin Yu Wenbin Yang Canzhong Lu Honghui Zhuang 《中国科学:化学(英文版)》2001,44(1):49-54
The reaction of an aqueous solution of sodium molybdate with iron powder at low pH (~0.184) gives rise to the formation of a six-member Mo ring-shape cluster with an Fe (II) encapsulated at the center, [Na4(H2O)7][Fe(OH)6Mo6O18](1), which is further linked to a remarkable three-dimensional network via sodium ions. 相似文献
59.
Wenbin Lu 《Annals of the Institute of Statistical Mathematics》2008,60(3):545-574
The proportional hazards cure model generalizes Cox’s proportional hazards model which allows that a proportion of study subjects
may never experience the event of interest. Here nonparametric maximum likelihood approach is proposed to estimating the cumulative
hazard and the regression parameters. The asymptotic properties of the resulting estimators are established using the modern
empirical process theory. And the estimators for the regression parameters are shown to be semiparametric efficient. 相似文献
60.
To develop a small molecule-based biomarker for in vivo apoptosis imaging, a dansyled amino acid derivative (BNSBA) was designed and synthesized in good yield. The biological evaluation demonstrated that BNSBA selectively binds to apoptotic cancer cells and is localized within the cytoplasm of cells that bound annexin V on the plasma membrane. 相似文献