$ D.L*
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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
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Shanghai Jiaotong University
,
Shanghai 200030
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China 2) Shanghai Volkswagen Automotive Company Limited
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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
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null
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null
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null
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null
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null
王华林
,
方大庆
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史铁钧
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翟林峰
高分子材料科学与工程
聚D,L-乳酸(PDLLA)的合成方法主要有直接法和间接法两种.间接法合成PDLLA的关键在于中间体D,L-丙交酯(DLLA)的制备.文中以D,L-乳酸为原料,在催化剂辛酸亚锡(ZnOct2)的作用下,合成DLLA.研究温度、压力、时间等因素对DLLA产率的影响,利用DSC、XRD、IR等分析测试技术对DLLA的性能和结构进行相关的测试和表征.研究结果表明,在反应体系中加入乙二醇作为稀释剂,能降低DLLA的馏出温度,避免了DLLA在蒸馏过程中产生炭化现象,并使DLLA的平均产率由36.8%提高至51.3%.
关键词:
聚D,L-乳酸
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D,L-丙交酯
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合成
舒静
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任丽丽
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王鹏
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王鉴
,
王刚
高分子材料科学与工程
研究了中等分子量((M)η=1.10×105)的聚D,L-乳酸在体外不同环境中的可降解性能,包括不同pH值溶液(37℃)和自然土壤.降解性能采用失重率、分子量变化、溶液pH值变化等来进行评价,并对试样表面形貌采用扫描电镜(SEM)进行了观察.结果表明:聚D,L-乳酸在体外环境中具有良好的可降解性,受降解环境的影响较大;失重和分子量的减小并不平行;在不同pH值溶液和土壤中的分子量变化在一定时间内符合一级反应动力学,且随溶液pH值的增大,降解速率减小.
关键词:
聚D,L-乳酸
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体外可降解性
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降解动力学
刘文慧
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张莹莹
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高磊
材料保护
304L(D)双牌号不锈钢产品的制造不可避免焊接过程,焊接接头也是最容易出现失效的位置,而现今304L(D)双牌号不锈钢的性能及使用在国内外均没有系统的研究及相应的标准.采用失重法结合腐蚀SEM形貌观察及蚀坑内部元素EDS谱,从腐蚀速率与化学成分方面分析了304L(D)双牌号不锈钢母材及焊缝的耐点腐蚀性能.结果显示:焊缝处耐点蚀性能最优而母材最次.所得腐蚀数据可以作为今后制定304L(D)双牌号不锈钢使用条件的参考.
关键词:
304L(D)双牌号不锈钢
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焊接接头
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点腐蚀
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失重
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腐蚀形貌
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成分分析
王建
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许兴友
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马卫兴
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赵宏
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陆路德
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杨绪杰
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汪信
人工晶体学报
新型氨基酸配位聚合物[Zn(L-trp)(D-trp)]n(L-trp和D-trp分别是L-色氨酸和D-色氨酸)通过水热法制备,并进行元素分析、红外光谱、单晶X-衍射等的表征.该化合物属三斜晶系,P-1,a=0.91670(10)nm,b=0.53320(6)nm,c=1.9525(2)nm,Z=2.为二维双链平面结构.此配位聚合物具有中心对称空间群.每个锌离子Zn2+与一对外消旋体配合,而形成内消旋化合物.
关键词:
色氨酸
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Zn(Ⅱ)配位聚合物
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混合溶剂热法
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表征
王华林
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方大庆
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史铁钧
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翟林峰
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王继植
应用化学
doi:10.3969/j.issn.1000-0518.2005.06.017
在催化剂辛酸亚锡(ZnOct2)的作用下,合成了聚D,L-乳酸(PDLLA). 研究了催化剂用量、反应温度和时间对PDLLA分子量的影响. 得到的最佳合成条件为:ZnOct2质量分数为0.5%,聚合温度为170 ℃,聚合时间为7 h. 考察了PDLLA在生理盐水中的降解情况,采用XRD对降解产物进行了表征. 结果表明,PDLLA降解时,先生成不溶于生理盐水的低聚物,然后生成可溶性的低聚物,并有(D,L)丙交酯形成,质量损失迅速增加,最终降解完全.
关键词:
聚(D
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L)-乳酸
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D
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L-丙交酯
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生理盐水
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降解性
段永华
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孙勇
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鲁俐
功能材料
doi:10.3969/j.issn.1001-9731.2013.24.016
基于密度泛函理论(DFT)的第一性原理赝势平面波方法,采用广义梯度近似(GGA),计算了立方结构 L12-TiAl3和 L12-Ti (Al,Pt)3及四方结构D022-TiAl3的电子结构与光学性质。计算结果表明L12-TiAl3和D022-TiAl3费米能级附近价带和导带主要是由Ti的3d 和 Al 的3p 轨道贡献,而 L12-Ti(Al, Pt)3费米能级附近价带和导带则主要是由Ti的3 d和Pt的6 s 轨道贡献；同时也计算了 L12-TiAl3、L12-Ti (Al,Pt)3和D022-TiAl3的介电函数、折射率、吸收系数和反射率等。
关键词:
L1 2-Ti (Al,Pt)3
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第一性原理
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电子结构
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光学性质
Journal of Applied Physics
The effect of 3d transition elements (such as V, Cr, Mn, Fe, Co, and Ni additions) on material properties in L1(0) TiAl has been studied using the first-principles DMol and discrete variational method within the framework of the density-functional theory. The transfer energy calculation indicates that all these 3d elements show a tendency to substitute for Al sites in the stoichiometric TiAl alloy, with the increasing order V < Cr < Mn < Ni < Fe < Co. Our results show that the local distortion of crystal lattice around an impurity atom is nonuniform, and it is found that the important influencing factors on the local lattice distortion are the impurity atom size and the site preference. Based on the effects of the doped alloying elements on the structural parameters and mechanical properties, we conclude that the larger bond strength and the smaller axial ratio benefit the ductility. (c) 2007 American Institute of Physics.
关键词:
alloying elements;site preference;electronic-structure;mn;substitutions;base alloys;compound;nb;deformation;occupancies;aluminides
李润岳
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段永华
中国有色金属学报(英文版)
doi:10.1016/S1003-6326(16)64361-3
为了更好地理解L12、D022和D023结构HfAl3的相对稳定性和键合特征，采用第一性原理计算了L12、D022和D023结构HfAl3的形成焓、电子结构和热力学性质。结果表明：平衡晶格参数与形成焓的计算结果与实验结果一致，不同结构的HfAl3稳定性大小为D023>D022>L12；态密度、电荷与键布局分析结果表明D023为最稳定结构；声子计算得到的热力学性质与温度的关系表明，D023结构的、熵和自由能随温度变化比L12和D022结构要快得多；L12、D022和 D023结构HfAl3的德拜温度分别为399、407和416 K；HfAl3的体积热膨胀系数在低温时成倍增加，而在高温时线性增加。
关键词:
第一性原理
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HfAl3
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电子结构
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热力学性质
Zhong CHU
材料科学技术（英）
Simulations are performed on temporal evolution of atom morphology and ordering parameters of Ni-14.5 Cr-16.5 Al alloy during early precipitation process at different temperatures based on microscopic phase-field theory; the relationship between precipitation sequence and mechanism of L12 and D022 structure and precipitation temperature are illuminated. The nonstoichiometric ordered L12 phases appear first with congruent ordering+spinodal decomposition mechanism which is then followed by precipitation of D022 phases at ordering domain boundaries of L12 phases by spinodal decomposition mechanism at 1073 K and 1223 K. The nonstoichiometric L12 phases transform to stoichiometric ordering phases gradually. The incubation period of L12 and D022 phases is shorter at 1073 K than that 1223 K, and growth speed is higher at 1073 K. At 1373 K, L12 and D022 phases appear simultaneously by non-classical nucleation and growth mechanism. After that the particles of D022 phases diminish and disappear gradually; L12 phases grow and single L12 phases are remained at last.
关键词:
Ni-Cr-Al
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微观相场
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沉淀
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序参数
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模拟
