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11.
无间隙原子钢的微观结构特征和塑性应变比 总被引:1,自引:0,他引:1
采用X射线衍射的ODF和LP分析技术,SEM电子通道花样和蚀坑技术观测,研究了超深冲无间隙原子钢板的微观结构特征。结果表明:控制化学成分、保证基体纯净、优选工艺参数,促进强的γ-〈111〉∥N.D纤维织构的形成是获得优异成型性的关键。用CMTP方法,由ODF织构数据从理论计算了塑性应变比(r),表明rm值高达3.18。文中讨论了再结晶织构形成机制。 相似文献
12.
《钢铁研究学报(英文版)》2006
Previous studies showed that the temperature coefficient of obviously decreases with increasing the content of heavy rare earth element in SmCo magnet. But the investigation on the hydrogen incorporation in SmCo magnet is limited. In this paper, we would like to report the effect of heavy rare earth dopant on hydrogen incorporation in SmCo 2:17 type magnet. The relationship between temperature and pressure in hydrogenatied magnet is studied using XRD, DTA, and magnetic measurement. Based on the experimental results, the initial hydrogenation temperature decreases with increasing the content of heavy rare earth, however, the initial saturation pressure enhances. During the hydrogenation, the temperature region shrinks with increasing heavy rare earth doping. 相似文献
13.
14.
Discretization of boundary integral equations leads, in general, to fully populated non-symmetric linear systems of equations. An inherent drawback of boundary element method (BEM) is that, the non-symmetric dense linear systems must be solved. For large-scale problems, the direct methods require expensive computational cost and therefore the iterative methods are perhaps more preferable. This paper studies the comparative performances of preconditioned Krylov subspace solvers as bi-conjugate gradient (Bi-CG), generalized minimal residual (GMRES), conjugate gradient squared (CGS), quasi-minimal residual (QMR) and bi-conjugate gradient stabilized (Bi-CGStab) for the solution of dense non-symmetric systems. Several general preconditioners are also considered and assessed. The results of numerical experiments suggest that the preconditioned Krylov subspace methods are effective approaches solving the large-scale dense non-symmetric linear systems arising from BEM. 相似文献
15.
《Composites Part A》2007,38(11):2283-2293
The study of the variation of the curvature of non-symmetric composite laminates with temperature provides a measure of the magnitude of the thermal stresses and the mechanical behavior of the material with temperature. In the present work, an experimental method based on the pioneer use of a digital camera and image processing method is proposed to perform such measurements. Taking advantage of the method and by comparing experimental and CLT, extended-CLT and FEM simulation results, an evaluation of the residual stresses is described and an approach providing more precise determination of the residual thermal stresses in non-symmetric laminates is proposed. 相似文献
16.
Effects of post-synthesis treatments on the pore structure and stability of MCM-41 mesoporous silica
《Materials Letters》2007,61(14-15):3119-3123
The effects of post-synthesis treatments on the structure and the stability of MCM-41 mesoporous material were investigated. It was found that, by adding ammonium salts and adjusting pH during the post-synthesis to alkalescently synthesized MCM-41, the regularity of the pore was improved dramatically and the stability of the mesostructure was retained; conversely, they were diminished by adding sodium salts. The results were studied by analyzing the samples using X-ray diffraction (XRD), Transmission electron microscopy (TEM), Differential Thermal Analysis–Thermal Gravimetry (DTA–TG). The change of the electrostatic surrounding and the formation of hydrogen bonds caused by different ions were confirmed to be the main factors. 相似文献
17.
《Diamond and Related Materials》2007,16(1):16-20
Detonation-synthesized nanocrystalline diamond is a novel carbon material. Its increased electrical conductivity, due to the features of giant specific surface area and large numbers of surface defects as well as the cluster structure, makes it possible to be used as an electrode material. Nanodiamond powder electrodes were fabricated and the electrochemistry was investigated by cyclic voltammetry and AC impedance measurement. The results show that nanodiamond powder electrode is electrochemically stable in KCl electrolytes over a wide potential range (− 1.2–2.0 V). The electrode reaction is quasi-reversible in 0.1 M KCl containing the ferricyanide–ferrocyanide redox couple. The electrode reaction rate constant k is estimated to be 2.87 × 10− 3 cm/s. The peak current increases linearly with the rising of the concentration of [Fe(CN)6]3−/4−. The AC impedance spectra have been analyzed and an equivalent circuit proposed. 相似文献
18.
分析了环氧乙烷,乙二醇装置工艺系统中有机酸生成的原因.指出在银催化剂作用下,乙烯氧化过程有机酸生成主要成分是甲酸和乙酸,银催化剂不是影响氧化反应器出口醛含量的主要因素;杂质、温度等对反应器出口气中的醛含量有重要影响,也直接影响到装置前系统的有机酸含量;乙二醇后系统中有机酸的增加仅取决于两级吸收及解析工艺的稳定操作。 相似文献
19.
本文以较为准确的轧机振动状态下的轧制压力模型为基础,对宽带钢冷轧机干摩擦阻尼减振进行了数值模拟的研究。研究结果与实际观测值相等。 相似文献
20.