$ D.L*
,
D.N.He
,
X.J.Bao
,
Y. Q.Zhang
,
X. Y.Ruan
,
J.L. Cheng and J. Y. Jiang 1) National Die & Mold CAD Engineering Research Center
,
Shanghai Jiaotong University
,
Shanghai 200030
,
China 2) Shanghai Volkswagen Automotive Company Limited
,
Shanghai 201805
,
China
金属学报(英文版)
With the combination of a new theoretical formula, physical simulation experiments, the technology of artificial neural network and database, an intelligent system for the prediction of sheet metal drawing capability is constructed for the first time. A modified criterion for sheet metal drawing capability is proposed in this paper, namely, the Technological Limiting Drawing Ratio, TLDR = f(R, n, s, t, F, μ,r_d,r_p…). Based on the studies of other scholars, a new formula is derived to predict the TLDR in this paper. Then a series of orthogonal physical simulation experiments are designed to investigate the effect of technological parameters on the TLDR, and the results are analyzed in the paper. Then the predicting system is constructed with the combination of the theoretical formula, orthogonal experiments, the technology of artifocial neural network and database. The predicted results show good agreements with experimental data, so it can be used to avoid the blindness in the selection of sheet metal before stamping. The system operates under the Windows operating system, and it supports the mechanism of Client/Server as well as Intranet, so the system has high engineering value.
关键词:
TLDR
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null
,
null
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null
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null
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null
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null
刘叔仪
金属学报
<正> 作为固体脆性断裂判据的J积分,其数值与其积分路径无关,这在文献中叫“守恒性”。这个守恒性已被推广到塑性断裂,这到底有否根据?本文目的是作这个问题的证明。未用原作者的方法,但由两个旋度判据得到应力应变函数行列式给出的一些否定结论,希望这对J积分应用条件的了解有所助益。1.弹塑性J积分守恒的条件 J积分
关键词:
朱杰武
,
柳永宁
,
许雁
,
冯耀荣
机械工程材料
doi:10.3969/j.issn.1000-3738.2005.06.007
在不同温度下测试了X70管线钢动态断裂韧度K1d、J1d和止裂韧度K1a以及夏氏V型缺口冲击韧度Ak,对三者的关系进行了分析.结果表明:温度和加载速率都对断裂韧度产生影响;加载速率变化引起的韧-脆断裂转变具有热激活特征,在热激活分析基础上,在应力强度因子速率K=15 MPa·m1/2s-1条件下,得出断裂韧度、止裂韧度和冲击韧度三者的关系:Ak=4.84×106T-2.8K1d(或K1a).可以用小试样Ak数据计算得到K1d和K1a.
关键词:
管线钢
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断裂韧度
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止裂韧度
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韧-脆断裂转变
L.F. Li
,
Z.P. Chen
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M.F. Jiang and W.Z. Wang(Department of Ferrous Metallurgy
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School of Materials and Motallurgy
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Northeastern University Shenyang 110006
,
China)(The Technology Center
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Baoshan Iron & Steel Complex
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Shanghai 201900
,
China)
金属学报(英文版)
The principle and steps for the calculation of component activities in fluxes using Schuhmann method are described. On the foris of Gibbs-Duhem equation and using Cr2O3 activities in BaO-BaF2-Cr2O3 system fiuxes, BaO activities at 1523 and 1673K are calculated, respectivelg,and the isoactivity diagrums of BaO are also obtained. The calculation results indicate that BaO activity increases with increasing its content in fiuxes, and decreaaes with the increase of Cr2O3 content at a given XBaO/XBaF2 ratio.
关键词:
Shuhmann method fluxes
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null
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null
Physical Review B
The Hamiltonian for a four-sublattice Heisenberg ferrimagnet or ferromagnet with different exchange constants (J(ab) = J(cd) not equal J(bc) = J(da)) was established. An extended Bogoliubov transformation was developed by solving an equation group, consisting of 20 equations and 20 unknowns. The procedure for solving the equation group was carried out by introducing a simple way of reducing the numbers of the equations and the unknowns. The spin-wave spectra in the present system have been determined by performing the standard Holstein-Primakoff transformation and the Bogoliubov one. It has been found that the spin-wave spectra of the present system depend on the exchange constants and that the degeneracy of the spin-wave spectra remains. The results for a special case (J(ab) = J(bc)) i.e., an antiferromagnet are discussed briefly. The spin-wave spectra of the four-sublattice Heisenberg antiferromagnet are found to be degenerative also and they are linear in k for small k.
关键词:
model
Physical Review B
The quadratic Holstein-Primakoff spin-wave Hamiltonian for three-sublattice Heisenberg systems with different exchange constants (J(ab)=J(bc)not equal J(ca)) was diagonalized by a three-step procedure. The classical ground state was examined and the effects of quantum fluctuation on the ground state were discussed. The 0 K spin reorientation angles due to quantum fluctuations were found to originate from the asymmetry of the system. As an extended application of the spin-wave study of the multisublattice systems, the spin-wave spectra of a Heisenberg superlattice, which has four or three magnetic atoms or spins, in each magnetic unit cell in the x direction, were solved analytically in terms of creation and annihilation operators. It has been found that the spin-wave spectra of the present superlattice systems depend on the exchange constants J and J(1), and that the degeneracy of the spin-wave spectra remains for the superlattice of four atomic layers and is partially removed for the superlattice of three atomic layers mainly due to the asymmetry of the system. Another type of splitting of the energy level occurs which differs for those levels with different degeneracies. The mixing of the interface and the bulk modes were found for the spin-wave dispersion of the superlattices. It was predicted that even for different superlattices having the same exchange constants (either J or J'), i.e., without the oscillation of the exchange coupling, the asymmetry can lead to the oscillation of magnetic properties, such as magnetization and giant magnetoresistance.
关键词:
ferromagnetic superlattices;reorientation transitions;magnetic;superlattices;modes;temperatures;film
陈英
,
何俊
,
马玉刚
,
陈小平
,
王乐夫
,
李雪辉
催化学报
采用共沉淀-浸渍法制备了新型催化剂Pt-Pd/BaO/TiAlO, 通过对催化剂进行NOx吸附储存实验、有硫(SO2)和无硫情况下的NOx储存-还原循环实验以及程序升温脱附、程序升温还原、N2吸附-脱附和X射线衍射等表征分析,考察了该催化剂的储存NOx性能以及抗硫性能. 结果表明,在Pt-Pd/BaO/TiAlO中,复合氧化物TiAlO为储存NOx的组分兼载体, Ti和Al原子比为1:2时,储存NOx能力最大;BaO (4%)作为助剂不但增加了催化剂的热稳定性,还提高了其储存NOx的能力. 与Pt/BaO/γ-Al2O3相比, Pt-Pd/BaO/TiAlO具有良好的抗硫性能. Pt-Pd/BaO/TiAlO上吸附形成的硫化物稳定性较差,易被还原脱除,这是其抗硫性能良好的原因之一.
关键词:
铂
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钯
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氧化钡
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钛铝复合氧化物
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氮氧化物
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储存-还原催化剂
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抗硫性能
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贫燃发动机尾气
