WANG Chengshan
,
MU Xiaojing
,
ZHENG Shaobo
,
JIANG Guochang
,
XIAO Xingguo
,
WANG Wenzhong
钢铁研究学报(英文版)
The molten liquid discrete flow inside a packed bed is a typical transport phenomenon in the blast furnace. As for the reported mathematical models presenting the liquid discrete flow within the packed bed, there are some barriers for their application to an engineering scaleup, or some imperfections in model descriptions. To overcome these deficiencies, the effects of the packed bed on the liquid discrete flow have been divided into resistance action and dispersal action, and appropriate descriptions have been given for the two actions, respectively. Consequently, a new mathematical model has been built to present the liquid discrete flow inside a coke bed in the blast furnace. The mathematical model can predict the distribution of liquid flux and the liquid flowing range inside the packed bed at any time. The prediction of this model accords well with the experimental data. The model will be much better for the simulation of the ironmaking process, compared with the existent model.
关键词:
mathematical model;liquid discrete flow;packed bed;blast furnace;ironmaking process
Journal of Materials Science
The response of mu phase to applied stress and long-term thermal exposure has been investigated in the cast Ni-base superalloy K446. It is found that during stress rupture, the applied stress accelerates the precipitation and growth of mu phase. However, during thermal exposure the mu phase precipitating in the form of needles and granules experiences a complicated evolution. The needles, fiber- or sheet-shaped in three-dimension, align very regularly during exposure, either lying in three directions with an acute angle to one another or in two directions perpendicular to each other, the mechanisms of which are characterized in detail. In addition, it is concluded that an excessive precipitation of mu phase severely degrades the mechanical properties of the alloy, whereas its evolution behavior during thermal exposure is determined to have an insignificant influence on the properties.
关键词:
single-crystal superalloy;thermal exposure;precipitation;stability;rupture;stress
Journal of Alloys and Compounds
Precipitation behavior of a topologically close packed (TCP) mu phase as well as its role during the creep deformation in single crystal superalloy CMSX-4 have been investigated. The mu particles nucleated and grew based on low index planes of both the mu phase ({11 (2) over bar 0} and {1 0 (1) over bar0}) and the matrix ({110}, {001} or {111} and {112}) by epitaxial growth toward < 0001 >(mu) or < 110 >gamma directions, which predominantly resulted in a rod-like morphology. Interestingly, composition of these rod-like mu particles varied with the ratio of Ni/(W + Re) due to the different diffusion rates of these elements in the matrix during thermal exposure. Moreover, the gamma' evolution played an important role in the precipitation behavior and the fracture behavior of the mu phase. The rod-like mu particles were not fractured by stress concentration, as they were surrounded by the gamma' envelope. (C) 2011 Elsevier B.V. All rights reserved.
关键词:
Nickel-base single crystal superalloy;Topologically close packed phase;Thermal exposure;Creep;nickel-base superalloys;ni;deformation;microstructure;mechanisms;diffusion;exposure;fatigue;design;damage
Materials Science and Engineering a-Structural Materials Properties Microstructure and Processing
The role of mu phase in a second generation directionally solidified Ni-base superalloy during high temperature creep has been characterized in the present work. A large amount of blocky mu phase enveloped by thick gamma'-film is found at the grain boundaries and in the vicinity of primary MC carbides after heat treatment. However, the creep-rupture properties of the alloy are not affected by the presence of the blocky p, phase at 760-1070 degrees C under a stress of 120-850 MPa. By the investigation of creep microstructure at 975 degrees C/255 MPa, it is found that the thick gamma'-film plays a pivotal role in toughening the grain boundaries and the interfaces between the mu phase (or carbides) particles and the matrix, and preventing the formation of cracks. Meanwhile, during high temperature creep, M(23)C(6) carbides are continuously coarsening with the dissolution of the p. phase particles and MC carbides, especially at the grain boundaries. The poor interface cohesion strength between such large M(23)C(6) carbides and the gamma matrix at the vertical segments of the directionally solidified grain boundaries leads to the final creep failure of the present alloy. (C) 2010 Elsevier B.V. All rights reserved.
关键词:
mu phase;Directionally solidified Ni-base superalloy;Creep;Carbide;Grain boundaries;precipitation
Journal of Physics D-Applied Physics
B-doped ZnO thin films were observed to have a lateral laser-induced photovoltaic effect: the saturation value varied very linearly with the 10.6 mu m constant laser spot position between the electrodes on the ZnO surface. It was found that the temperature gradient in the direction of electron transfer (along the film surface) due to the laser spot causes this photovoltage signal to be linearly dependent on the position of the laser spot in this isotropic system. This linearity is expected to make ZnO a candidate for position-sensitive photodetectors.
关键词:
ultraviolet photodetectors
卓玲
,
陈宝璠
硅酸盐通报
利用废弃混凝土加工成的再生骨料制作再生混凝土空心砌块.在混凝土空心砌块配合比参数优化设计的基础上,以再生骨料混凝土空心砌块抗压强度作为评定指标,采用正交试验方法,研究再生骨料混凝土空心砌块配合比设计.研究结果表明:对于再生骨料混凝土空心砌块,以85％再生粗骨料取代率和100％再生细骨料取代率,选取合适配合比,其强度等级是可以达到MU5.0的.
关键词:
再生骨料混凝土空心砌块
,
再生粗骨料取代率
,
配合比
,
设计
Journal of Magnetism and Magnetic Materials
The first principle within the full potential linearized augmented-plane-wave (FP-LAPW) method was applied to study the compound of Co[N(CN)(2)](2)(L) [L = pyrazine dioxide (pzdo) and 2-methyl pyrazine dioxide (mpdo)] with dual mu- and mu 3-[N(CN)(2)](-) bridges. The density of states, the electronic band structure and the spin magnetic moment are calculated. The calculations reveal that these two compounds have a ferromagnetic (FM) interaction arising from the 1,5-mu- and mu 3-[N(CN)(2)](-) bridges. The spin magnetic moment mainly comes from the Co ion with little contribution from N, O and C anions. (C) 2007 Elsevier B.V. All rights reserved.
关键词:
ab initio;FP-LAPW;electronic structure;ferromagnetic property;networks;molecule;ni;co
Acta Physico-Chimica Sinica
The electronic structure and magnetic properties of the moleculer-based magnet [Cu(mu-cbdca)(H(2)O)](n) (cbdca=cyclobutanedicarboxylate) compound with copper ions as the metallic magnetic center were studied using the FP_LAPW(first-principle full-potential linearized augmented plane wave) method of first-principles, based on density functional theory (DFT) with generalized gradient approximation (GGA) method and local spin density approximation (LSDA) method. The total energies of the ferromagnetic, antiferromagnetic. and non-magnetic phases of organic-inorganic metal phosphonoacetate [Cu(mu-cbdca)(H(2)O)](n) were calculated. The calculations revealed that the compound [Cu(mu-cbdca)(H(2)O)](n) had a stable metal-ferromagnetic ground state, which was in agreement with the experimental result. There were large and positive spin populations on copper (II) ions, small and positive populations on the oxygen and carbon atoms of the bidentate ligand, which connected to the copper ions.
关键词:
density functional theory;electronic structure;FP LAPW;molecular magnets;azido;copper(ii);complexes;carboxylate;nickel(ii);bridges;system;ligand
