材料期刊网

Effect of Vibrational Modes on Sand Pressure and Pattern Deformation in the EPC Process

A.Ikenaga , G.S.Cho , K.H.Choe , K.W.Lee

材料科学技术（英文）

During the EPC (expendable pattern casting) process, one of the essential requirements is to prevent pattern distortion during sand filling and compaction. A new method which vibrates the system in a two-dimensional circular mode has been applied to the EPC process. The molding properties of unbonded sand obtained by this new vibration mode are investigated and compared with those in the one-dimensional vertical mode. For adequate compaction of sand, the circular vibration mode is more effective than the vertical mode. Sand became more fluidized by the circular vibration and the particle pressure coefficient was close to unity. The particle pressure coefficient, which is defined as the ratio of horizontal to vertical sand pressure, is responsible for the effectiveness of sand filling.

关键词: EPC process , null , null , null , null

PS/粉末SBR-g-S共混体研究Ⅱ.粉末SBR-g-S的相结构及其与PS的相容性

王炼石 , 周奕雨 , 夏新江

高分子材料科学与工程

测定了SBR-g-S的接枝率,用TEM检测了粉末SBR-g-S(PR)的相结构.用DSC测定了PS/PR共混体的Tg,研究了PS/PR共混体的相容性.结果发现,在接枝率为32.6%的粉末非交联SBR-g-S(PR1)的相结构中SBR为连续相,在连续相中均匀分布着直径约0.01 μm的PS微区;PS为细胞状分散相,粒径1～5 μm,分散相含有SBR包藏物.在接枝率为8.5%的粉末交联SBR-g-S(PR2)的相结构中PS为连续相,SBR为分散相,分散相粒径约0.3 μm.共混体PS/PR1的相容性优于PS/PR2.SBR在PS富相中有较高的含量是导致PS/PR1共混体在冲击断裂时发生剪切屈服的主要原因.

关键词: 粉末SBR-g-S , 相结构 , PS/粉末SBR-g-S , 共混体 , 相容性

Explanations of the optical spectra and g factor for V3+ ions in ZnX (X = S, Se, Te) crystals

Physica B-Condensed Matter

This paper presents a cluster approach for the calculations of the absorption band positions and the g factor of d(2) tetrahedral cluster. In the approach, the different modifications of e and t(2) orbitals of d electrons and the contribution from the spin-orbit coupling of ligands to the EPR g factor due to the mixing of d(2) ions with the ligands are considered. The calculated band positions and g factor for ZnX : V3+ (X = S, Se, Te) crystals show good agreement with the observed values by using only two adjustable parameters. The contribution from the spin-orbit coupling of ligands to the g factor is discussed. (C) 1998 Elsevier Science B.V. All rights reserved.

关键词: crystal- and ligand-field theory;optical spectra;electron paramagnetic;resonance;spin-orbit coupling;V3+ ZnX (X = S, Se, Te);vanadium centers;znte crystals

CS-KPS复合体系引发S-g-PAM反相胶乳的研究

卢绍杰 , 刘瑞贤 , 孙希明 , 卫乃勤 , 杨光中

高分子材料科学与工程

以K2S2O8为引发剂,研究了在反相乳液中合成淀粉接枝聚丙烯酰胺共聚物(S-g-PAM),实验证明,加入少量铈离子组成复合体系,对提高反应速率、接枝率和接枝效率起到显著的促进作用.文中对硫酸铈-过硫酸钾(CS-KPS)体系的用量及反应影响因素进行了探讨.

关键词: 淀粉接枝 , 丙烯酰胺 , 复合引发体系 , 反相胶乳

ER70S-G焊丝焊接工艺性能的研究

黄治军 , 王玉涛 , 胡家国

钢铁研究

为提高气保焊丝的焊接工艺性能,选用不同化学成分的ER70S-G焊丝进行焊接工艺试验。当焊丝含某种元素X质量分数为0.09%、w（Mn）为1.50%及w（Si）为1.0%时,CO2气体保护焊接飞溅极少,但焊缝宽高比较小,为3.5;当焊丝含某种元素X质量分数为0.01%、w（Mn）为1.70%及w（Si）为0.8%时,CO2气体保护焊接飞溅较少,焊缝宽高比较大,为4.5,显示出很好的焊接工艺性能。结果表明,焊丝的成分对气保焊缝的成形有很大的影响,在某种元素X质量分数、w（Ti）及w（Si）/w（Mn）比适当时,可得到焊接飞溅小、焊缝成形佳的焊接工艺性能。

关键词: ER70S-G , 气保焊 , 飞溅 , 成形

含钛焊丝钢ER70S-G夹杂物演变分析

刘善喜 , 张彩军 , 吕达 , 马德刚 , 李硕

钢铁钒钛 doi:10.7513/j.issn.1004-7638.2016.05.008

为开发含钛焊丝钢ER70S-G,对其冶炼过程中夹杂的数量、尺寸和类型进行研究.研究发现:在精炼过程中,钢中当量直径夹杂物的数目呈现逐渐降低的趋势;到中间包时,当量直径(5μm)夹杂物数目已经从包样的19.78个/mm2减少到1.66个/mm2;精炼过程夹杂物的平均直径呈逐渐降低的趋势,平均直径为2.05 μm;精炼初期,钢中夹杂物类型主要是MnO-SiO2夹杂,到加钛铁前,钢中的主要夹杂物转变为CaO和MgO,从加钛铁后到中间包期间,Al2O3-Ti2O3-MgO系夹杂是钢中的主要夹杂物.

关键词: 含钛焊丝钢 , 夹杂物 , 数量 , 尺寸 , 类型

PBLG-PEG-PBLG嵌段共聚物的合成及其CHO细胞毒性

王琴梅 , 滕伟 , 张静夏 , 潘仕荣

应用化学 doi:10.3969/j.issn.1000-0518.2006.09.006

以端氨基聚乙二醇(AT-PEG)引发谷氨酸苄酯N-羧酸酐(BLG-NCA)开环聚合得到聚谷氨酸苄酯-聚乙二醇-聚谷氨酸苄酯嵌段共聚物(PBLG-PEG-PBLG,缩写为GEG),用GPC、IR、1H NMR测试技术表征了共聚物的结构;在GEG膜表面培养中国仓鼠肺泡成纤维细胞(CHO),用光学显微镜和扫描电子显微镜观察聚合物表面细胞粘附、生长、繁殖的情况. 结果表明,AT-PEG能引发BLG-NCA开环聚合形成嵌段共聚物,所有的聚合物都没有细胞毒性,细胞在某些共聚物上的生长和繁殖比均聚物好.当PEG的分子量为2 000,且PEG单体单元的摩尔含量占共聚物中总单体含量的59%时,细胞不能贴附在共聚物表面. 通过控制共聚物中PEG嵌段的含量可调节细胞在聚合物表面上的粘附和生长.

关键词: 聚谷氨酸苄酯 , 聚乙二醇 , 嵌段共聚物 , 细胞毒性

Relationship between the brittlement susceptibility and H permeation current for UNS g11180 steel in 5% NaCl solution with H2S

材料科学技术（英文）

Sulfide stress corrosion cracking (SSCC) behaviour of UNS G11180 steel in 5% NaCl solution with H2S was, studied by slow strain rate tensile test (SSRT), SEM and electrochemical hydrogen permeation technique. The results reveal different cracking mechanism and H permeation current (I-H) through UNS G11180 steel plate in different concentration of H2S solution. The susceptibility to SSCC of UNS G11180 steel in 5% NaCl solution with H2S was evaluated by the permeation current (I-H, mu A), which depends on the concentration (c x 10(-6)) of H2S by the equation: I-H = 8.525 x c(0.7249). It is proved that the electrochemical H permeation method is a practical way to assess the susceptibility to SSCC.

关键词: cracking

Relationship between the Brittlement Susceptibility and H Permeation Current for UNS G11180 Steel in 5% NaCl Solution with H_2S

Xueyuan ZHANG and Yuanlong DU(State Key Lab. for Corrosion and Protection , Institute of Corrosion and Protection of Metals , Chinese Academy of Sciences , Shenyang 110015 , China)

材料科学技术（英文）

Sulfide stress corrosion cracking (SSCC) behaviour of UNS G11180 steel in 5% NaCl solution with H2S was studied by slow strain rate tensile test (SSRT), SEM and electrochemical hydro gen permeation technique. The results reveal different cracking mechanism and H permeation current (IH) through UNS G11180 steel plate in different concentration of H2S solution. The susceptibility to SSCC of UNS G11180 Steel in 5% NaCl solution with H2S was evaluated by the permeation current(IH, μA), which depends on the concentration (c×10-6) of H2S by the equation:IH = 8.525 ×c0.7249. lt is proved that the electrochemical H permeation method is a practical way to assess the susceptibility to SSCC.

关键词:

Explanation of the EPR g factors for Co2+ impurities in trigonal Cd2P2S6 crystal

Physica B-Condensed Matter

By extending the theory of Abragam and Pryce, the formulas of EPR parameters g and g(perpendicular to) for 3d(7) ion in trigonal octahedral crystals are established from a cluster approach. In these formulas, not only the configuration interaction effect, but also the covalency effect are considered and the parameters related to both effects and the trigonal distortion are determined from the optical spectra and the structural data of the crystal under study. Based on these formulas, the g(parallel to) and g(perpendicular to) of Cd2P2S6: Co2+ crystal are reasonably explained from its structural data. The relationship between the sign of Deltag (= g(parallel to) - g(perpendicular to)) and the trigonal distortion (elongated or compressed) of ligand octahedron, which is opposite to that obtained in the previous paper, is given and the results are discussed. (C) 2001 Elsevier Science B.V. All rights reserved.

关键词: electron paramagnetic resonance;crystal- and ligand-field theory;trigonal distortion;Co2+;Cd2P2S6;superposition model;transition;complexes;ion