P. R. Ding
,
D. Y. Ju
,
T. Lnouc and E. de Vries( 1) MSC Japan Ltd.
,
Osaka
,
Japan 2) Saitama Institute of Technology
,
Saitama
,
Japan 3) Kyoto Universily
,
Kyoto
,
Japan 4) MacNeal - Schwendler (E. D. C. ) B. V.
,
Gouda
,
The Netherlands)
金属学报(英文版)
A method to simulate processes of forging and subsequent heat treatment of an axial symmetric rod is formulated in eulerian description and the feasibility is investigated. This method uses finite volume mushes for troching material deformation and an automatically refined facet surface to accurately trace the free surface of the deforming material.In the method,the deforming work piece flows through fixed finite volume meshes using eulerian formulation to describe the conservation laws,Fixed finite volume meshing is particularly suitable for large three-dimensional deformation such as forging because remeshing techniques are not required, which are commonly considered to be the main bottelencek in the ssimulations of large defromation by using the finite element method,By means of this finite volume method, an approach has been developed in the framework of "metallo-thermo-mechanics" to simulate metallic structure, temperature and stress/strain coupled in the heat treatment process.In a first step of simulation, the heat treatment solver is limited in small deformation hypothesis,and un- coupled with forging. The material is considered as elastic-plastic and takes into account of strain, strain rate and temperature effects on the yield stress.Heat generation due to deformation,heat con- duction and thermal stress are considered.Temperature - dependent phase transformation,stress-in- duced phase transformation,latent heat,transformation stress and strain are included.These ap- proaches are implemented into the commerical commercial computer program MSC/SuperForge and a verification example with experimental date is given as comparison.
关键词:
finite volume method
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null
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null
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null
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null
K. Mii (Sumitomo Metal Industries
,
Ltd.
,
1-t-3 Otemachi
,
Tokyo 100
,
Japan)M Amano (National Research Institute for Metals
,
1-2-1 Sengen
,
Tsukuba 305
,
Japan)
金属学报(英文版)
The R & D of hydrogen absorbing alloys in Japan started in the early 1970s.Many alloys such as TiMm1.5 based alloys, Fe-Ti-O alloys (e.g. FeTi1.15 O0.024) andthe(mischmetal)Ni5 based alloys (e.g. MmNi4.5 Cr0.46 Mn0.04) were developed by the early 1980s. The application of these alloys to hydrogen storage, heat storage, heat pump, hydrogen purification and motor vehicles has been tried in many iaboratories,and the various techniques for using hydrogen absorbing alloys have been developed.The standarkization of evaluation methods for hydrogen absorbing alloys has been promoted by the Ministry of International Trade and Industry (MITI), and four of them were established as Japanese Industrial Standard (JIS).Alloys for Ni-Metal Hydride batteries have been extensively investigated since 1987in Japun. Mm-Ni-Co-Al-Mn alloys (e.g. MmNi3.55 Co0.75Al0.9Mn0.4) have been devel-oped and commereialized since 1990. The amount of production of small-size Ni-MH batteries in 1995 was about three hundred milliion in number and about one hundred billion yen. The R & D for higher enerpy-density Ni-MH batteries is intensively in progress.MITI and STA (Science and Technology Agency) have promoted the R & D of hydro-gen absorbing alloys in Japan by carrying out the national projects such as Sunshine Program (MITI: 1974-1993) and Utilization of Wind Engeray (STA 1980-1985). The New Sunshine Program (MITI 1993-2020) have started in 1993. This program con-tains the application of hydrogen absorbing alloys to Economical- Enerpy- City System and to We-NET (International Clean Energy System of Technology Utilizing Hydro-gen: World Energy Network.
关键词:
hydrogen absorbing alloy
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null
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null
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null
Chemical Physics Letters
The relationship between the local structure and EPR spectrum is studied by diagonalizing the complete energy matrices for Mn(2+) in a trigonal ligand-field. The results show that the degree of distortion increases with temperature increasing whether it is compressed or elongate distortion, and the distorted tendency of the local structure is different according to the sign of D. Meanwhile, the distortion of Cd(BF(4))(2)center dot 6H(2)O:Mn(2+) system is more sensitive to temperature than that of ZnSnF(6)center dot 6H(2)O:Mn(2+) system. Moreover, the EPR parameter D is closely associated with the local structure parameters R and h while (a - F) is mainly concerned with R. (C) 2010 Elsevier B. V. All rights reserved.
关键词:
single-crystals;optical-absorption;phase-transitions;mn2+;field;ions;resonance;spectra;relaxation;fe-3+
Journal of Magnetism and Magnetic Materials
CoFe(2)O(4)/Fe(3)O(4) nano-composite ceramics were synthesized by Spark Plasma Sintering. The X-ray diffraction patterns show that all samples are composed of CoFe(2)O(4) and Fe(3)O(4) phases when the sintering temperature is below 900 degrees C. It is found that the magnetic properties strongly depend on the sintering temperature. The two-step hysteresis loops for samples sintered below 500 degrees C are observed, but when sintering temperature reaches 500 degrees C, the step disappears, which indicates that the CoFe(2)O(4) and Fe(3)O(4) are well exchange coupled. As the sintering temperature increases from 500 to 800 degrees C, the results of X-ray diffractometer indicate the constriction of crystalline regions due to the ion diffusion at the interfaces of CoFe(2)O(4)/Fe(3)O(4) phases, which have great impact on the magnetic properties. (C) 2011 Elsevier B. V. All rights reserved.
关键词:
CoFe(2)O(4)/Fe(3)O(4) nano-composite ceramic;Exchange spring behavior;SPS;Magnetic property;cofe2o4 nanoparticles;dependence;media;films;mgoe
Acta Chimica Sinica
Passive film formed on 304 stainless steel in 2.5 mol/L H2SO4 solution by using alternating voltage (A. V.) passivation have been investigated by measuring capacitance and photoelectrochemical parameters. The investigation of the effect of measure frequency on the slope of Mott-Schottky curve has been carried out. The photoelectrochemical measurements were consistent with the capacitance measurement. Analysis of the experimental results showed that the passive film formed 304 stainless steel by using A. V. passivation exhibits semiconducting properties. Using the simple model of semiconductor rather than the multi-donor level model can explain satisfactorily the semiconducting behavior of the film formed on 304 stainless steel by using A.V. passivation.
关键词:
A. V. passivation;passive film;semiconducting properties;stainless;steel;model;electrodes
Physics Letters A
The magnetic properties of the mixed ferro-ferrimagnetic compounds with (A(a)B(b)C(c))(y)D, in which A, B, C and D are four different magnetic ions and form four different sublattices, are studied by using the Ising model. And the Ising model was dealt with standard mean-field approximation. The regions of concentration in which two compensation points or one compensation point exit are given in c-a, b-c and a-b planes. The phase diagrams of the transition temperature T-c and compensation temperature T-comp are obtained. The temperature dependences of the magnetization are also investigated. Some of the result can be used to explain the experimental work of the molecule-based ferro-ferrimagnet ((NiaMnbFecII)-Mn-II-Fe-II)(1.5) [Cr-III (CN)6] - zH(2)O. (C) 2003 Elsevier B.V. All rights reserved.
关键词:
mixed ferro-ferrimagnet;Ising model;four sublattices;phase diagram;transition temperature;compensation temperature;magnetic-properties;prussian blue;alloy
高秀秀
,
张永青
,
李春丽
,
王华
影像科学与光化学
doi:10.7517/j.issn.1674-0475.2016.05.465
本文报道了对一种电子给体-受体化合物(E)-(5-(4-(二苯基胺)苯乙烯基)二噻吩并[2,3-b∶3',2'-d]噻吩基)-2-亚甲基丙二腈(TPA-DCST)的合成与光谱学行为的研究.化合物TPA-DCST的分子结构中含有强电子给体(三苯胺)与强电子受体(二氰基乙烯)两个部分,并由二噻吩并[2,3-b∶3',2'-d]噻吩作为共轭桥将电子给体与受体相连接.在合成方面,采用Wittig反应将三苯胺通过双键与二噻吩并[2,3-b∶3',2'-d]噻吩相连接、醛基化,并与并二腈经Knoevenagel缩合反应合成目标产物.产物通过了核磁氢谱、碳谱、红外以及高分辨率质谱的确认.光谱方面,主要考察了该化合物的吸收与荧光行为.其最大吸收峰位在412 nm左右,归属于7π-7π*跃迁.在非极性溶剂正己烷中表现出来自分子间聚集而形成的聚集态荧光(550nm),并通过了单分子在CTAB胶束([c]=1.02×10-2 mol/L)的发光(460 nm)试验得到验证.溶剂效应表明,该化合物没有出现典型的ICT态的发光现象,其原因在于电子给体与受体相连的共轭桥单元,即二噻吩并[2,3-b∶3',2'-d]噻吩不具有有效的共轭效应.浓度效应与温度效应进一步表明TPA-DCST分子易于产生分子间聚集态的发光.在THF-H2O二元溶剂体系中呈现典型的聚集诱导(AIE)发光现象,发光峰位为692 nm.随着TPA-DCST分子间的聚集程度的增加,聚集态的荧光出现大范围的红移,直至固体发光红移到710 nm.TPA-DCST分子的聚集因素可能来自于疏脂作用、偶极-偶极相互作用等.
关键词:
D-A化合物
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二噻吩并[2,3-b∶3',2'-d]噻吩共轭桥
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浓度效应
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温度效应
,
聚集诱导发光
Journal of Alloys and Compounds
Nd-Fe-(B.C) alloys have been synthesized by mechanical alloying and subsequent heat-treatment, with B4C as one of the starting materials. It is found that when the pure B4C is milled alone, it proves difficult to decompose. When the B4C compound is milled with Nd and Fe, the complete decomposition of B4C and the formation of Nd2Fe14(B,C) phase is observed. Furthermore, the competition between B and C atoms for entering the Nd2Fe14B lattice. the effects of the B4C content on the structure and the magnetic properties of Nd2Fe14(B,C)-based alloys are investigated. A coercivity as high as 18.3 kOe and the maximum energy product of 10.4 MGOe have been achieved for the Nd-Fe-(B,C) alloys. (c) 2005 Elsevier B.V. All rights reserved.
关键词:
permanent magnets;mechanical alloying;fe-c alloys;permanent-magnets;r2fe14c;nd
Chemical Physics Letters
By analyzing EPR and optical spectra, the local lattice structures of (NiF6)(4-) clusters in perovskite fluorides RbMF(3) (M = Cd(2+), Ca(2+), Mg(2+)) series in tetragonal and trigonal ligand field are studied. A compression distortion relative to the regular octahedron for the RbCdF(3): Ni(2+) and RbCaF(3): Ni(2+) systems is determined. Furthermore, on the basis of the complete energy matrices we found that ZFS parameter D dependence on spin-orbit coupling coefficient zeta is not a strictly quadratic relation as shown by the fourth-order perturbation formula. Finally, the curves of g(parallel to) versus k and g(perpendicular to) versus k for these three systems are plotted which satisfy an approximately linear relation. (c) 2008 Elsevier B. V. All rights reserved.
关键词:
phase-transitions;critical fluctuations;rbcaf3;scattering;crystals;ions;centers;rbcdf3;kmnf3;ni2+
