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101.
102.
M Ohata T Ichinose N Furuta A Shinohara M Chiba 《Canadian Metallurgical Quarterly》1998,70(13):2726-2730
To establish a method for sensitive, accurate, and precise determination of Se in real samples, isotope dilution analysis using high-power nitrogen microwave-induced plasma mass spectrometry (N2 MIP-IDMS) was conducted. In this study, freeze-dried human blood serum (Standard Reference Material, NIES No. 4) provided by NIES (National Institute for Environmental Studies) was used as a real sample. The measured isotopes of Se were 78Se and 80Se which are the major isotopes of Se. The appropriate amount of a Se spike solution was theoretically calculated by using an error multiplication factor (F) and was confirmed experimentally for the isotope dilution analysis. The mass discrimination effect was corrected for by using a standard Se solution for the measurement of Se isotope ratios in the spiked sample. However, the sensitivity for the detection of Se was not so good and the precision of the determination was not improved (2-3%) by N2 MIP-IDMS with use of the conventional nebulizer. Therefore, a hydride generation system was connected to N2 MIP-IDMS as a sample introduction system (HG-N2 MIP-IDMS) in order to establish a more sensitive detection and a more precise determination of Se. A detection limit (3 sigma) of 10 pg mL-1 could be achieved, and the RSD was less than 1% at the concentration level of 5.0-10.0 ng mL-1 by HG-N2 MIP-IDMS. The analytical results were found to be in a good agreement with those obtained by the standard addition method using conventional Ar ICPMS. 相似文献
103.
Takeshi Naito Hideo Ueda Masao Kikuchi 《Metallurgical and Materials Transactions A》1984,15(7):1431-1436
The characteristic fatigue behavior of carburized and quenched steel with internal oxides and non-martensitic microstructure near the surface was presented through rotating bending fatigue test. The S-N diagram revealed two knees and the specimens continued to fail over 107 stress cycles. The fatigue limit could not be obtained even at 108 stress cycles. The test results were compared to those for the specimens without surface structure anomalies to show the effect of structure anomalies on the fatigue behavior of carburized steel. 相似文献
104.
Masahiro Sugaya Masakazu Takeshi Tomoji Yamashiki Toshio Oikawa Kan-Ichi Fujii 《Electromagnetic Compatibility, IEEE Transactions on》1982,(1):20-25
Correlation of light emission, discharge structure, waveform of the discharge current, electrode configuration, and electromagnetic radiation is examined with the intent of obtaining an effective means for preventing electromagnetic interference (EMI) due to a short-gap discharge. The electromagnetic radiation (EMR) level resulting from a current step which, in turn, was formed by a discrete movement of a cathode spot was clearly recognized. A combination of needle rotor and needle post gave the smallest electromagnetic radiation level in the experiments. 相似文献
105.
This paper presents a finite strip analysis of curved composite girders with incomplete interaction. In the present analysis curved composite girder bridges are modelled by curved strip elements for the concrete slab and steel girder and spring elements for the shear connectors. The shear connectors are assumed as a two-dimensional spring element along the nodal line. The proposed method is applied to the analysis of curved box girders, curved plates and curved composite girder bridges with complete and incomplete interaction. Some analytical results obtained by this method are compared with the test results and theoretical values obtained by other methods, and they are in good agreement. Slip behavior of curved composite box girders is also discussed based on the results by the proposed method. 相似文献
106.
107.
An identification procedure for determination of coefficients of pulse transfer function is proposed. This procedure is applicable for the case when measurement noises of input and output are independent of input to a process and the variances of the noises are known only in the form of the ratio. The noises can be colored. The criterion used for identification is given by extending the mean-square equation error. The optimal estimates are obtained from the eigenvector of a linear operator which corresponds to the least eigenvalue. The theoretical analysis is given and the direction for the practical usage is suggested to use the least-square error criterion. 相似文献
108.
109.
The relationship between ductility and material parameters such as grain-boundary (GB) precipitate size and dimple size in an Al-6.0% Zn-2.6% Mg alloy has been studied. Under the condition of a given GB precipitate size, the ductility increases with decreasing number of GB precipitates and dimples per unit area. The critical GB precipitate sizes acting as the nuclei for void formation are deduced. 相似文献
110.
Certain non-crystalline germanium films (> 10 μm in thickness) prepared by rf-sputtering crystallize “explosively” at room temperature when initiated by pricking the surface with a sharp point (or certain other methods). The propagation velocity of the crystallization at room temperature was found to be as fast a 1200 mm sec?1 depending somewhat on the conditions of film preparation, thickness, etc. The density of several such crystallizable films was determined as 5.05 g cm?3±1%. The crystallite size in the crystallized films, measured by X-ray broadening, was typically larger than 500 Å. A model for the crystallization process invokes a cascade energy transfer process, basically thermal in nature. 相似文献