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Yoji Mine Daisuke Haraguchi Zenji Horita Kazuki Takashima 《Philosophical Magazine Letters》2015,95(5):269-276
We subjected samples of a 304 metastable austenitic stainless steel to high-pressure torsion (HPT) in the temperature range of 303–573 K, (i.e. at different austenite stabilities), to examine their microstructures and mechanical properties. HPT processing at room temperature led to the formation of a lamellar microstructure with austenitic and martensitic phases, of which sizes were characterised by prior austenite grains, whereas HPT processing at moderate temperatures produced nanostructured austenite grains through mechanical twinning. The nanostructured 304 steel with an average grain size of ~70 nm exhibited a fine balance between tensile strength (~1.7 GPa) and reduction of area (~55%). 相似文献
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王帅 《医学与哲学(人文社会医学版)》2010,31(8A):79-81
诺贝尔生理学或医学奖已有百余年历史,其间遗传学获奖项目运用了很多实验材料。它们有的已淡出人们的视线;有的还在使用,并频繁获奖;呈现出此起彼伏、交相更迭的"诺贝尔医学奖实验材料更替现象"。本文旨在探讨与诺贝尔生理学或医学奖相关的遗传学实验材料更替现象,总结其更替规律,并在此基础上预测其选用趋势。 相似文献
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A. M. Mazzone 《Philosophical Magazine Letters》2013,93(5):235-238
Abstract In this work results of a Monte Carlo simulation of the ion penetration in a crystalline silicon target are reported. It is shown that, contrary to the common expectation, channelling is sustained by a non-vanishing divergency of the ion beam for a nominally random orientation of the target. 相似文献
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The partitioning of the trace element Sn into Cu-rich precipitates in a low-alloy pressure-vessel steel has been characterized using the three-dimensional atom probe (3DAP) technique. This investigation has revealed for the first time that the trace element Sn, present at only 0.007?at.% in the steel, partitions strongly to both small spherical precipitates (<4?nm in diameter) and to large non-spherical precipitates (largest dimension 10–50?nm) during thermal ageing. Sn was also seen to segregate strongly to the precipitate/matrix interface of a large Cu precipitate and particularly in the region where a dislocation appears to intersect the precipitate. The strong attraction of large solute atoms to special sites probably drives the interfacial segregation of Sn. This is consistent with the observation of stronger segregation of Sn to the interface of large precipitates than to the coherent interface of smaller precipitates. 相似文献
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In this letter we employ high-precision Monte Carlo simulations to investigate tracer diffusion kinetics for diffusion via divacancies in the bcc lattice. We utilize the mechanisms originally identified by Mehrer in which the divacancy can move by nearest-neighbour jumps with stable first-nearest-neighbour, second-nearest-neighbour and fourth-nearest-neighbour configurations of the divacancy. The tracer correlation factor and the 'impurity-form' correlation factor were found to be some 4-6% lower than those found by the matrix method. The tracer diffusion data and isotope effect for sodium were revisited in terms of monovacancy and divacancy contributions. The main change is a revision upwards from 0.55 to 0.61 of the j K kinetic factor for divacancies. 相似文献
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A highly supersaturated nanocrystalline Cr–25?wt% Zr alloy has been prepared by mechanical alloying of elemental crystalline powders. High-purity powders of Cr and Zr were milled for up to 20?h. The development of the microstructure was investigated by X-ray diffraction (XRD) and scanning electron microscopy. XRD patterns confirmed complete alloying of the Zr and Cr. The contribution of grain boundaries, the chemical potential of a solute atom induced by dislocations, and the elastic strain energy arising from the different sizes of Cr and Zr atoms have been calculated. The alloy formation is discussed with respect to the thermodynamic conditions of the material. The role of internal strains and stored enthalpies by dislocations on solute atoms is the major mechanical driving force for alloying and this is critically assessed in this article. 相似文献
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Savaş Sönmezoğlu Yakup Ulusu Fatma Gedikli Özlem Ateş Sönmezoğlu İsa Gökçe 《Philosophical Magazine Letters》2013,93(5):211-216
We have fabricated a molecular organic light-emitting device comprising indium–tin oxide/a molecular organic layer/aluminum in which the organic layer is a green fluorescent protein. The device exhibits peak external quantum and power efficiencies of 8?±?0.2% and 13?±?0.7?lm?W???1 at a current of J?=?1.5?A?m?2, respectively. In addition, the turn-on voltage is 2.5?V for 1?cd?m?2 and the maximum luminance achieved is 1275?cd?m?2. This good performance can be explained by the presence of singlet-excited states, leading to a high internal efficiency. 相似文献
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In this paper, based on the perspective of carbon emissions, the regional environment and regional innovation strategies were analyzed by using cybernetics. The main idea was to calibrate the diesel engine simulation model with predictive function based on the data collected from the bench test, and then according to the simulation model, the genetic algorithm was applied to optimize the EGR parameters and fuel injection parameters with the target of emission generation and output torque. First of all, the combustion process and emission performance of diesel engine with internal exhaust re-circulation were studied by genetic algorithm, and the genetic algorithm model was constructed. Then, the genetic algorithm program was written based on Matlab. In addition, taking the NOx emission as the target, and the Soot emission and the output torque of the original machine as constraints, through the joint simulation of Matlab and GT-Power, the EGR parameters and fuel injection parameters of the 10% to 50% load conditions were optimized at the speed of 1500 r/min and 2000 r/min. Finally, the validity of this method was verified and analyzed. 相似文献