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991.
运用穆斯堡尔效应和X射线衍射方法对辐照前后的316L不锈钢样品中的穆斯堡尔参数和相变进行了研究。实验表明316L不锈钢经能量为54MeV的碳离子辐照后,在结构和微观参数上都发生了重大变化。同时也对样品中碳的分布和相变的类型进行了探讨。 相似文献
992.
A new heat-resistant Fe-based cast alloy has been designed making the best use of the CALPHAD method. The objective was to replace the material for precision cast products made from Ni-based superalloys with improved Fe-based alloys originally developed for lower temperature applications.The key to the design is to balance the amount of strengthening - Ni3(Ti,Al) precipitates and brittle phase, and to simultaneously decrease as-cast microsegregation. Contours of the equal phase fraction were calculated over the isothermal diagrams of the Fe–Ni–Cr–Ti–Al–Nb system, and provided useful guidelines for compositional modifications. The microsegregation was also evaluated by Scheil-type simulation in order to reduce micropores caused by oxidation of the solidifying front.The developed cast Fe-based alloy showed desirable strength at the envisioned service temperatures and filled the open range of heat resistance between Ni-based superalloys and the original alloy. 相似文献
993.
用短锥旋流器分选黄铁矿的试验研究 总被引:1,自引:0,他引:1
黄铁矿通常用浮选的方法回收 ,本文通过对黄铁矿、脉石物理性能的研究 ,用重选使黄铁矿和脉石实现分离 ,对主要分离设备———短锥旋流器的工作原理及效果进行了探讨。试验表明 ,短锥旋流器是黄铁矿分离的有效设备。 相似文献
994.
995.
Ney Sodr Pablo Guillermo Gonzales-Ormeo Helena Maria Petrilli Cludio Geraldo Schn 《Calphad》2009,33(3):576-583
The metastable phase diagram of the BCC-based ordering equilibria in the Fe–Al–Mo system has been calculated via a truncated cluster expansion, through the combination of Full-Potential-Linear augmented Plane Wave (FP-LAPW) electronic structure calculations and of Cluster Variation Method (CVM) thermodynamic calculations in the irregular tetrahedron approximation. Four isothermal sections at 1750 K, 2000 K, 2250 K and 2500 K are calculated and correlated with recently published experimental data on the system. The results confirm that the critical temperature for the order–disorder equilibrium between Fe3Al–D03 and FeAl–B2 is increased by Mo additions, while the critical temperature for the FeAl–B2/A2 equilibrium is kept approximately invariant with increasing Mo contents. The stabilization of the Al-rich A2 phase in equilibrium with overstoichiometric B2–(Fe,Mo)Al is also consistent with the attribution of the A2 structure to the τ2 phase, stable at high temperatures in overstoichiometric B2–FeAl. 相似文献
997.
We address the problem of permutation ambiguity in blind separation of multiple mixtures of multiple images (resulting, for instance, from multiple reflections through a thick grass plate or through two overlapping glass plates) with unknown mixing coefficients. In this paper, first we devise a generalized multiple correlation measure between one gray image and a set of multiple gray images and derive a decorrelation-based blind image separation algorithm. However, many blind image separation methods, including this algorithm, suffer from a permutation ambiguity problem that the success of the separation depends upon the selection of permutations corresponding to the orders of the update operations. To solve the problem, we improve the first algorithm above by decorrelating the mixtures while searching for the appropriate update permutation using a pruning technique. We show its effectiveness through experiments with artificially mixed images and real images. 相似文献
998.
Due to the solar radiation intensity variation over time, the outlet temperature or mass flow rate of heat transfer fluid (HTF) presents non-steady-state characteristics for solar collector. So, in the phase change thermal energy storage (PCTES) unit which is connected to solar collector, the phase change process occurs under the non-steady-state inlet boundary condition. In present paper, regarding the non-steady-state boundary, based on enthalpy method, a two dimensional physical and mathematical model for a shell-and-tube PCTES unit was established and the simulation code was self-developed. The effects of the non-steady-state inlet condition of HTF on the thermal performance of the PCTES unit were numerically analyzed. The results show that when the average HTF inlet temperature in an hour is fixed at a constant value, the melting time (time required for PCM completely melting) decreases with the increase of initial inlet temperature. When the initial inlet temperature increases from 30 °C to 90 °C, the melting time will decrease from 42.75 min to 20.58 min. However, the total TES capacity in an hour reduces from 338.9 kJ/kg to 211.5 kJ/kg. When the average inlet mass flow rate in an hour is fixed at a constant value, with the initial HTF inlet mass flow rate increasing, the melting time of PCM decreases. The initial inlet mass flow rate increasing from 2.0 × 10−4 kg/s to 8.0 × 10−4 kg/s will lead to the melting time decreasing from 37.42 min to 23.75 min and the TES capacity of PCM increasing from 265.8 kJ/kg to 273.8 kJ/kg. Under all the studied cases, the heat flux on the tube surface increases at first, until it reaches a maximum then it decreases over time. And the larger the initial inlet temperature or mass flow rate, the earlier the maximum value appearance and the larger the maximum value. 相似文献
999.
以正硅酸乙脂试剂、乙醇试剂及蒸馏水为原料,运用溶胶—凝胶工艺制备了无定形纯SiO_2,采用TG-DTA、XRD等方法研究了SiO_2在加热晶体化过程中的相变特性。 相似文献
1000.