最新刊期
卷 26 ， 期 2 ， 1987
- 摘要：The North River drainage forms on the basis of that the Yian Mountain and Himalayan movement result in distribution of tectonoclastic zones and weak rocks as well as sequence of height of redstoene basin and by means of that flows in original six biger pieces of isolated redstone basins join progressively by the action of river piracy. It is main that the earth’s crust uplifts spasmodically in the early, middle period since a million years. late. The North River Drainage forms many steps of stream terrace. In the late period, the two structure zones of Yao Mountain and the Sanlian——Sannan move obviously, fall of the crust is prevailing on vast areas, moreover, sea level varies, the Yuantan Stream is early formed at middle part of the North River Drainage, the pearl River Delta is late formed at the south part, along this drainage from the north to the south the finst step of river terrace deforms and forms into a terrace, a semi——buried berraee and a buried terrace
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发布时间：2023-12-11 - 摘要：The O-alkylation of S(-)-1,1’-bis-2-naphthol [S(-)-1],or R(+)-1 with various alkyl halides in the presence of potassium fluoride hydrate was studied. It was found that mono-alkyl ether (3) was the major product, when S-1 or R-1 reacted with aliphatic monobromide or iodde in DMF at 100℃ under neutral reaction conditions. A good to exceillent yield of 3 was obtained when primary or secondary alkyl halide was used. No racemization was determined by the method of either optical rotation or proton nuclear magnetic resonance with chiral shift reagent. This synthetic method was also extended to methylene dihalide. When it reacted with S-1, for example, a cyclic ether S-5 was obtained in the yield of 84%.关键词： -Bi-2-naphthol;1;1’-Bi-2-naphthyl alkyl ethers;Alkylation;Axially dissymmetric biaryls;Potassium fluoride
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发布时间：2023-12-11 - 摘要：Pseudomonas sp. B-33 isolated from the contaminated environment is capable of growth in the presence of 100uM HgCl2. Three kinds of plasmids were detected in agarose gel electrophoresis. The mercuric reducing activity was measured and verified in the strain by atomic absorption spectroscopy. A cured derivative of B-33 was obtained by NTG treatment. This strain lacks one of the 3 plasmids in B-33 and fails to grow in the pressence of 100uM HgCl2. The mercuric reducing ability was markedly decreased in the cured strain. The cured plasmid （designated pBH33） was isolated and purified by electrophoresis and open circular DNA molecules were observed under electron microscpe. There are one site for EcoRI, two sites for PstI and four sites for Hind Ⅲ The molecular weight of pBH33 was estimated to be about 7.24×106d. by agarose electrophoresis. The cured strain was transformed by pBH33 and mercuric resistant ability was recovered.
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发布时间：2023-12-11 - 摘要：Optical properties of a system consisting of thin Au film and Si substrate have been measured by a spectroscopic ellipsometry over the range from ultraviolet to visible light. The ideal abrupt interface model is no longer reasonable for explaining the experimental results. The influences of voids, surface roughness and transition interface layer on ellipsometric spectra and the formation of an Au-Si alloy interface layer, in which the optical properties are described by a classical vibrator model, have been analysed. Our calculated results show that the formation of an Au-Si alloy interface lager is the major factor influening the ellipsometric spectra of Au film-Si substrate systems. The ellipsometric spectra calculated from our analysis fit in with the measured values.After low temperature annealing (100℃, 10min.) Si atoms migrate through the Au film to the surface where they react with oxygen and form an oxide layer.关键词： metal-semiconductor contact;interface;optical properties of solids;ellipsometry
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发布时间：2023-12-11 - 摘要：The baryon magnetic moments are studied phenomenologically by introducing the parameters r and for the mass ratios m_u/m_d and m_u/m_s respectively and the mass correction parameter ε for the mass of diquark compared with the sum of quark masses. We fit the experimental values of baryon magnetic moments using two sets of values for r, and ε. The theoretical predictions are in general agreement with experimental values. The fit is better with m_d关键词： Baryon magnetic moments;Baryon mass spectrum;Quark mass ratios
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发布时间：2023-12-11 - 摘要：Using a soft x-ray photoemission spectroscopy (SXPS), a chemical reaction is observed on the GaAs(110) surface with about 0.7 monolayer (ML) coverage of oxygen when Al is deposited at room temperature. The Al(<1ML)tendentiously reacts with surface oxygen bonded with As, then A1(>1ML) reacts with the others bonded with Ga, until all of the oxygen is consumed and additional Al replaces Ga in subsurface layers of the GaAs to form AlAs and drive Ga out across the interface. SXPS results show that on a similar oxygen covered surface only weak reaction is observed when Au deposition is below 1 ML. It is quite evident that additional Au (>1ML) disturbs the As-O bond and produces stable Ga oxide which inhibits the Ga below the oxide layer into Au, but As is segregated onto Au
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发布时间：2023-12-11 - 摘要：Presents the analysis of the natural vibration of the cylindrical mast in ship adopting the assumptions of both the membrane stress and the unvariability of the transverse section and using the synthetic discrete method. A numerical example is added in illustration of the proposed method. Some results of the calculation are given.It is concluded that the synthetic discrete method is a better method which can not only reduce highly the number of the unknown independent variables, but also keep on enough accuracy.关键词： natural vibration;Synthetic discrete method;assumptions of the membrane stress;assumptions of the unvariability of the transverse section
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发布时间：2023-12-11 - 摘要：The ratios of stereoisomeric products in the hetero-and homogeneous DielsAlder additions of cyclopentadiene to acrolein in various solvents (diethyl ether,acetone, dichloromethane, ethanol and water) were determined. The endo/exo product ratio of the homogeneous reactions in the solutions increases slightly with increasing solvent polarity; Ia the heterogeneous:Diels-Alder reactions, however,the distribution of the products in different media is not a simple relationship.
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发布时间：2023-12-11 - 摘要：The electrodeposited iron-nickel alloys with composition ranging from 10 to 27 at% Fe were investigated by means of Mossbauer spectroscopy etc. Distribution of the hyperfine field in these f. c. c. iron-nickel alloys was determined from the observed Mossbauer spectra. The relation between the widths of the outer and the inner lines was discussed. The intensity ratios of six lines were not equal to 3:2:1:1:2:3 since the ferromagnetic domain distribution in the samples was not random. The influence of the distribution of the electrical field in the bath was discussed. The great change in intensities of the second and the fifth lines for samples with same composition was observed. This is due to the fact that the plating layers were located at distinct positions in electrical field during the electrodeposited process. No iron oxide appears in these iron-nickel alloys which were placed in a chemical laboratory and exposed in air for 33 months. This indicates that the electrodeposited iron-nickel alloys have a high ability of corrosion resisting.关键词： electrodeposited;iron-nickel alloys;hyperfine field;spin orientation
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发布时间：2023-12-11 - 摘要：The insertion of a polyhedrin/β-galactosidase fusion gene into Trichoplusia ni nuclear polyhedrosis virus (NPV) genome has been achieved by using an Autographa californica NPV polyhedrin substitution vector E. coli plasmid pGP-B6874/Sal. A remarkably high level of the fused gene expression has also been obtained.关键词： DNA recombination;Baculovirus;Trichoplusia ni. β-Galactosidase Gene
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发布时间：2023-12-11 - 摘要：Peroxidases from Vinca rosea tissue cultures have been separated by polyacrylamide gel electrophoresis and isoelectric focusing into 6-13 isozymes. The isozyme pattern of callus tissues and those of plants at different development stages have been compared. The callus was obviously responsive to exogenous hormones.The isozyme pattern of the calluses cultured with different exogenous hormones was significantly changed. The subcultural and original callus had basically similar isozyme patterns when they were cultured under the same hormones condition.60Co irradiation of callus with dose of 25210 rad did not inhibit cellular growth and produced a new isozyme band.At different developmental stages of the plants, the isozyme patterns of their roots, stems and leaves were not similar, the healthy seedling’s have changed much than the young seedling’s and those of the old seedlings has three new isozyme bands at pI8-9.5关键词：Isoelectric pattern;Peroxidase;isozyme;Vinca rosea;tissue culture
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发布时间：2023-12-11 - 关键词： Channidae;Nucleolus Organizer regions
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发布时间：2023-12-11
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