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161.
In the presence of palladium salts, oxidation of 2-nitrostyrenes 1 with nitrous acid alkyl esters 2 resulted in the formation of 2-nitrophenylacetaldehyde dialkyl acetals 3. Reductive cyclization of the acetals 3 with iron powder in acetic acid afforded indoles 5 in good yield.  相似文献   
162.
A BSO spatial light modulator (BSO-SLM) was operated applying ac voltage. The basic properties of the operation correspond to those in a usual lock-in detector and a 2-dimensional lock-in detector array (2D-LOCKIN) was implemented by the optical modulator. The properties of the 2D-LOCK-IN using a BSO-SLM were investigated theoretically and experimentally. As an application of the 2D-LOCK-IN, oscillating amplitude were observed on simple vibrating objects.  相似文献   
163.
A hybrid binary subtracted joint transform correlator was constructed using a Bi12SiO12 (BSO) spatial light modulator and a laser scanner. The usefulness of this system was confirmed experimentally using a large number of binary and halL-tone images as the reference patterns.  相似文献   
164.
We have mechanically fabricated Ni and Cu nano-constrictions in solution to study their quantized conductance behavior under electrochemical potential control. Conductance quantization was observed at both metals in solution at room temperature for the first time. The conductance of Cu nano-constriction was quantized in units of G0(=2e2/h). A sharp 1G0 peak was observed in the conductance histogram. For Ni, a rather broad peak at 1–1.5G0 was observed in the histogram. The conductance quantization behavior was discussed by comparing previously documented results of nano-constrictions fabricated in air or ultra-high vacuum conditions, with those fabricated in solution.  相似文献   
165.
疋田巧 《化学教育》2002,23(7):92-94
日本的教育体制大体上类似于其他国家,即小学6年,初中3年,高中3年,大学本科4年。大学本科毕业后另有2年硕士学位,再加3年博士学位的教育。当前在校学习的人数逐年增加,人均在校学习的时间也逐渐延长。到2000年已有将近一半的18岁同龄人进入大学学习。为适应上述教育情况的变化,日本政府目前开始了一个重整大学教育体制的计划。该计划将所有原来模式相同的649所大学划分为两大类,一类是研究和教学型的,另一类是教学型的。目前已有9所大学已被认定为第一类型的大学。本文介绍日本教育体制的变化以及上述重整计划的长远目标。  相似文献   
166.
A computational technique which is based on a numerical-asymptotic expansion matching for computing the local singular behavior of a viscous flow around a sharp right-angle expansion corner is presented. Moffatt's (1964) asymptotic solution is extended and a matching with a time-marching finite-difference scheme of the Navier--Stokes equations is formulated. Local mesh refinement around the corner is required to meet the validity of the asymptotic solution. Flows in an expanding channel with expansion ratio D/d=3 at various Reynolds numbers 1≤Re≤700 are simulated. The results are compared with those from a standard finite-difference scheme that uses second-order forward/backward differences near the corner. It is found that the results of the standard scheme converge toward those of the present technique as the level of local refinement near the corner is increased. The time-dependent parameters of the first two terms of the asymptotic solution at the steady-state solution are also described for various cases of Re and D/d. It is demonstrated that the present method enhances the accuracy of the simulations and requires less refinements near the corners to achieve converged numerical results. Received 14 August 2000 and accepted 25 October 2001  相似文献   
167.
A copper‐catalyzed aminoboration of bicyclic alkenes, including oxa‐ and azabenzonorbornadienes, has been developed. With this method, amine and boron moieties are simultaneously introduced at an olefin with exo selectivity. Subsequent stereospecific transformations of the boryl group can provide oxygen‐ and nitrogen‐rich cyclic molecules with motifs that may be found in natural products or pharmaceutically active compounds. Moreover, a catalytic asymmetric variant of this transformation was realized by using a copper complex with a chiral bisphosphine ligand, namely (R,R)‐Ph‐BPE.  相似文献   
168.
169.
Instrumental neutron activation analysis with the internal standardization was applied to the precise determination of Br in polypropylene resin of candidate certified reference material. The known amount of 197Au was used as an internal standard to compensate for neutron flux inhomogeneity, to improve the γ ray measurement uncertainty and the linearity of the calibration curves. The reliability of the proposed method validated using analytical results of BCR-681. The analytical result of Br in the sample was consistent with that obtained by ID-ICPMS. The relative expanded uncertainty (k = 2) was 1.5 %, and it was equivalent to that of ID-ICPMS.  相似文献   
170.
The synthetic IgG‐binding domain (Z domain) of staphylococcal protein A catalyzes the oxidation of coelenterazine to emit light like a coelenterazine‐utilizing luciferase. The Z domain derivatives (ZZ‐gCys, Z‐gCys and Z‐domain) were purified and the luminescence properties were characterized by comparing with coelenterazine‐utilizing luciferases, including Renilla luciferase, Gaussia luciferase and the catalytic 19 kDa protein of Oplophorus luciferase. Three Z domain derivatives showed luminescence activity with coelenterazine and the order of the initial maximum intensity of luminescence was ZZ‐gCys (100%) > Z‐gCys (36.8%) > Z‐domain (1.1%) > bovine serum albumin (BSA; 0.9%) > staphylococcal protein A (0.1%) and the background value of coelenterazine (0.1%) in our conditions. The luminescence properties of ZZ‐gCys showed the similarity to that of Gaussia luciferase, including the luminescence pattern, the emission spectrum, the stimulation by halogen ions and nonionic detergents and the substrate specificity for coelenterazine analogues. In contrast, the luminescence properties of Z‐gCys were close to the catalytic 19 kDa protein of Oplophorus luciferase. The catalytic region of the Z domain for the luminescence reaction might be different from the IgG‐binding region of the Z domain.  相似文献   
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