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991.
α-(Trifluoromethyl)styrene and its derivatives have found wide applications in the fields of pharmaceuticals, agrochemicals, and advanced materials. They are also versatile trifluoromethyl-containing building blocks for the preparation of various trifluoromethyl-containing, fluorine-containing or nonfluorinated compounds. Recently, great efforts have been made to develop diverse reactions for rapidly accessing a wide range of valuable gem–difluoroalkenes and gem–difluoroalkylated compounds via d... 相似文献
992.
993.
We developed a modified protocol for the oxidation of 2,3‐allenyl alcohols using CuCl with 1:1 combination of phenanthroline and bipyridine as the catalyst. To further investigate the applicability of this system, other types of alcohols such as allylic and propargylic alcohols have been tested: we found that both allylic and propargylic alcohols may be oxidized to the corresponding aldehydes or ketones using molecular oxygen in air as the oxidant with moderate to excellent yields. 相似文献
994.
995.
Influence of H2O/DEZ ratio on LPCVD ZnO:B films for application in a-Si:H/μc-Si:H tandem solar cells
M. Wan H. Zhu Y. Wang J. Yin J. Gao Z. Wang F. Guan Y. Mai Y. Huang W. Yu S. Huang 《Applied Physics A: Materials Science & Processing》2014,115(1):297-303
In this study, boron doped zinc oxide (ZnO:B) films were prepared at different water to diethyl zinc (H2O/DEZ) flow ratios from 0.6 to 1.4 by a low pressure chemical vapor deposition (LPCVD) technique. It is found that the morphology of ZnO:B films varies from small leaf-like to pyramidal surface structures with the increasing H2O/DEZ flow ratio. The rough ZnO:B films deposited at a relatively H2O/DEZ flow ratio such as 1.2 or 1.4 show a high haze value of up to 28 % at 600 nm and $\mathrm{a} (11\overline{2}0)$ preferential crystallographic orientation. All ZnO:B films were applied in hydrogenated amorphous silicon/microcrystalline silicon tandem solar cells (a-Si:H/μc-Si:H) as front electrodes. The efficiency of the solar cells increases with the increasing H2O/DEZ flow ratio, which is attributed to a high spectral response mainly in the long-wavelength range and the consequent enhancement of short-circuit current. A high-efficiency a-Si:H/μc-Si:H tandem solar cell of 10 % was achieved. The H2O/DEZ ratio is an important process parameter to tune the material properties of LPCVD ZnO:B films and the performances of corresponding silicon thin film solar cells. 相似文献
996.
This article deals with the development of an original sample preparation method for transmission electron microscopy (TEM) using focused ion beam (FIB) micromachining. The described method rests on the use of a removable protective shield to prevent the damaging of the sample surface during the FIB lamellae micromachining. It enables the production of thin TEM specimens that are suitable for plan view TEM imaging and analysis of the sample surface, without the deposition of a capping layer. This method is applied to an indented silicon carbide sample for which TEM analyses are presented to illustrate the potentiality of this sample preparation method. 相似文献
997.
998.
Let G(n,k,t) be a set of graphs with n vertices,k cut edges and t cut vertices.In this paper,we classify these graphs in G(n,k,t) according to cut vertices,and characterize the extremal graphs with the largest spectral radius in G(n,k,t). 相似文献
999.
In many medical studies,the prevalence of interval censored data is increasing due to periodic monitoring of the progression status of a disease.In nonparametric regression model,when the response variable is subjected to interval-censoring,the regression function could not be estimated by traditional methods directly.With the censored data,we construct a new response variable which has the same conditional expectation as the original one.Based on the new variable,we get a nearest neighbor estimator of the regression function.It is established that the estimator has strong consistency and asymptotic normality.The relevant simulation reports are given. 相似文献
1000.
Electrostatic surface trap for cold polar molecules on a chipElectrostatic surface trap for cold polar molecules on a chipElectrostatic surface trap for cold polar molecules on a chip
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We propose a simple scheme for trapping cold polar molecules in low-field seeking states on the surface of a chip by using a grounded metal plate and two finite-length charged wires that half embanked in an insulating suhstrate, calculate the electric field distributions generated by our charged-wire layout in free space and the corresponding Stark potentials for ND3 molecules, and analyze the dependence of the trapping center position on the geometric parameters. Moreover, the loading and trapping processes of cold ND3 molecules are studied by using the Monte Carlo method. Our study shows that the loading efficiency of the trap scheme can reach 11.5%, and the corresponding temperature of the trapped cold molecules is about 26.4 inK. 相似文献