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141.
In this paper, we show that a multiplication operator on the Dirichlet space D is unitarily equivalent to Dirichlet shift of multiplicity n + 1 (n ≥ 0) if and only if its symbol is c zn+1 for some constant c. The result is very different from the cases of both the Bergman space and the Hardy space. 相似文献
142.
This study demonstrates a tunable Fresnel lens in an azo-dye-doped liquid crystal (ADDLC) film using an interference technique. One Fresnel-patterned green beam using a Sagnac interferometer irradiated the UV-illuminated ADDLC cell, yielding a concentric zone plate distribution with homeotropic and isotropic structures in bright and dark regions of the green interference pattern. The proposed Fresnel lens is polarization independent, focus tunable, and the focusing efficiency of the device can be optically controlled. 相似文献
143.
Yung-I Chen Bo-Lu LinYu-Chu Kuo Jen-Ching Huang Li-Chun Chang Yu-Ting Lin 《Applied Surface Science》2011,257(15):6741-6749
To prevent Co diffusion from cemented carbides at high temperatures, we fabricated TaNx coatings by reactive direct current (d.c.) magnetron sputtering onto 6 wt.% cobalt cemented carbide substrates, to form diffusion barrier layers. Varying the nitrogen flow ratio, N2/(Ar + N2), from 0.05 to 0.4 during the sputtering process had a significant effect on coating structure and content. Deposition rate reduced as the nitrogen flow ratio increased. The effects of nitrogen flow ratio on the crystalline characteristics of the TaNx coatings were examined by X-ray diffraction. The TaNx coatings annealing conditions were 500, 600, 700, and 800 °C for 4 h in air. We evaluated the performance of the diffusion barrier using both Auger electron spectroscopy depth-profiles and X-ray diffraction techniques. We also investigated oxidation resistance of the TaNx coatings annealed in air, and under a 50 ppm O2-N2 atmosphere, to evaluate the fabricated layers effectiveness as a protective coating for glass molding dies. 相似文献
144.
Defang Duan Xiaoli Huang Changbo Chen Fubo Tian Kuo Bao Da Li Yunxian Liu Hongyu Yu Bingbing Liu Tian Cui 《ChemInform》2014,45(49):no-no
The high pressure crystal structure of BI3 with space group P21/c consisting of B2I6 dimers is determined using an ab initio evolutionary algorithm for crystal structure prediction in conjunction with density functional theory. 相似文献
145.
Direct Synthesis of Chiral 3‐Arylsuccinimides by Rhodium‐Catalyzed Enantioselective Conjugate Addition of Arylboronic Acids to Maleimides 下载免费PDF全文
Dr. Balraj Gopula Shu‐Han Yang Ting‐Shen Kuo Prof. Dr. Jen‐Chieh Hsieh Dr. Ping‐Yu Wu Dr. Julian P. Henschke Prof. Dr. Hsyueh‐Liang Wu 《Chemistry (Weinheim an der Bergstrasse, Germany)》2015,21(31):11050-11055
Chiral rhodium catalysts comprising 2,5‐diaryl‐ substituted bicyclo[2.2.1]diene ligands L1 – L10 were utilized in the enantioselective 1,4‐addition reaction of arylboronic acids to N‐substituted maleimides. In the presence of 2.5 mol % of RhI/ L2 , enantioenriched conjugate addition adducts were isolated in 72–99 % yields with 86–98 % ee. This protocol offers a convenient method to access a variety of 3‐arylsuccinimides in a highly enantioselective manner. Maleimides with readily cleavable N‐protecting groups were tolerated enabling the synthesis of useful synthetic intermediates. Pyrrolidine 4 , a biologically active compound, and pyrrolidine 5 , an ent‐precursor to an HSD‐1 inhibitor, were synthesized to demonstrate the utility of this method. 相似文献
146.
The electrical interaction between two long, parallel cylinders each is covered by an ion-penetrable charged membrane immersed in an oil/water interface is investigated. The effects of contact angle, radius of cylinder, and membrane thickness on the electrical interaction force are examined. The results of numerical simulation reveal that the following conditions lead to a greater electrical interaction force: (i) a larger contact angle, i.e. a larger fraction of a cylinder in the oil phase; (ii) a larger cylinder radius; and (iii) a thinner membrane. For a fixed ionic strength, the electrical interaction force is insensible to the type of electrolytes in the water phase, in general. However, if two cylinders are close enough, then the higher the valence of counterions the greater the electrical interaction force. 相似文献
147.
以流动模式(flow mode)多极板之电流变阀(electrorheological valve)进行避震器阻尼力特性的研究。由于电极板的大小直接影响到流体流动的剪力及避雷器的阻尼力,因此使用多极板型式来探讨避震器的特性。设计有1-5个流道之并联及1-3个流道之串联多极板电流变阀的电流变避震器,并使用自制的电流变液进行实验。由研究结果显示,流动式并联极板之电流变避震器,一个流道之阻尼力最大,流道极板增加则阻尼力反而下降,而流动式串联多极板之电流变避震器之阻尼力则随极板数递增,故需要高阻尼力之避震器较适合使用串联多极板型式。 相似文献
148.
Iso-condensed heteroaromatic pyrroles 1 are 10 -electron aromatic compounds. They are of interest from both theoretical and synthetic points of view. They are the cyclic analogues of heteroaromatic ortho-quinodimethanes 2, and can react with dienophiles in a Diels-Alder reaction to give the synthetically useful cycloadducts 3. Many of them are also of potential pharmaceutical importance because they are isosteric with indoles. Iso-condensed heteroaromatic pyrroles 1 can be used also as the monomers for the synthesis of new conducting polymers 5 with special properties and characteristics. However, the methods for the efficient preparation of the iso-condensed heteroaromatic pyrroles are quite limited. Iso-condensed heteroaromatic pyrroles are generally unstable in acidic conditions and are easily oxidized by air. In our laboratories, we developed three methods for the preparation of this labile heterocyclic ring system under acidic, neutral, and basic conditions.1 Synthesis of the conjugated systems such as 6 for OLED applications will also be discussed. 相似文献
149.
This investigation compares the photodegradation performance of C.I. Reactive Red 2 (RR2) in single- and coupled-photocatalyst
systems. The photocatalysts were produced via the sol-gel method. PEG and Pt addition increases the decolorization rate (1.6–2.12
h−1), the amount of sulfate released and the DOC reduction percentage in coupled photocatalyst systems the cause of PEG improving
the homogeneity of the final product and incorporating Pt into the lattice reduced the band gap of photocatalysts. 相似文献
150.
An efficient clean-up procedure coupled with a high performance liquid chromatography (HPLC) with on-line electrochemical (EC) reduction and fluorescence detection (FLD) was developed to quantify nitrated polycyclic aromatic hydrocarbons (NPAHs) in the airborne particulate. In this process, NPAHs were extracted ultrasonically followed by analysis by using a reversed phase column with an aqueous eluent containing 70% aqueous acetonitrile and sodium monocholoroacetate as a buffer solution. The extraction efficiencies were above 83% for 1-nitropyrene and 1,3-dinitropyrene (1,3-DNP) 1,6-DNP, and 1,8-DNP, and calibration graphs were linear with very good correlation coefficients (r>0.999) and the detection limits were in the range of 1.0-2.2 pg for dinitropyrenes and nitropyrene. The proposed method provides a relatively simple and convenient procedure for determining the NPAHs samples in airborne particulate. 相似文献