W.S.Cho
,
T.S.Yoon
,
C.O.Kim
,
H.B.Lee
材料科学技术（英文）
The transverse permeability ratio (TPR) and longitudinal permeability ratio (LPR) as a function of an external field of mumetal films have been investigated in conjunction with the magnetic properties. The mumetal films were prepared by the R.F.magnetron sputtering method in Ar atmosphere. The LPR curve shows the single peak pattern, and the TPR curve shows the double peak pattern indicating the existence of the magnetic anisotropy effect. The magnitude of the incremental permeability are strongly depended on the magnetic softness. The large changes of LPR and TPR in low external fields can be useful for the evaluation of the magnetic softness.
关键词:
Transactions of Nonferrous Metals Society of China
The method for preparing a new solid lubrication system of nano S-W-S was presented. The microstructure of the S-W-S nano cluster was investigated using TEM and XRD. The system is a mixture clusters of both monocrystal and polycrystal of layered hexagonal structure with one tungsten atom linking with two sulphur atoms, and the week Van der Waals' force bonding together the different layers. The changes of electronic structure were studied with XPS. The hybridization of different electronic shelf orbitals of the sulphur atom in the nano cluster is regarded as the quantum size effect. The clusters are found to be of a closed spherical,structure without any dangling bond.
关键词:
solid lubrication system;nanometer cluster;quantum size effect;powders
鲁二敬
,
卢峰华
,
许鸿吉
,
谢明
,
钮旭晶
机械工程材料
通过周期浸润腐蚀试验，对比研究了S355．12W耐候钢和Q345R低合金钢在NariSOs溶液中的耐腐蚀性能，并用扫描电镜对腐蚀产物进行了观察和分析。结果表明：在相同试验条件下，S355J2W耐候钢的腐蚀速率低于Q345R钢的；S355J2W耐候钢会在表面形成黑褐色锈层，而Q345R钢表面形成橘红色易剥落的疏松锈层；S355J2W耐候钢腐蚀产物微观形貌为沿放射性方向生长的针状晶体，Q345R钢为颗粒状聚合物堆积而成，形状无规则，颗粒之间有较大的空隙。
关键词:
S355J2W耐候钢
,
周期浸润腐蚀试验
,
耐腐蚀性能
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
WU Shaobin
,
R. J. Arsenault
,
I. R. Kramer Metallurgical Materials Laboratory
,
University of Maryland
,
USA.
材料科学技术（英文）
Intergranular stress corrosion cracking (ISCC) of α-brass in neutral Mattsson's solution was found to be controlled by an unusual "W"-shaped galvanic cell whose cathode is the grain boundary oxide film (G.B.0. film) and surface film and the anode is fresh metal at the cracked tip on both sides of the G.B.0. film. Redox reactions involved in the cell have been proposed here. According to this mdel, initidtion of ISCC is caused by the rupturing of surface film along grain boundaries, thus forming a galvanic cell. Propagation of ISCC resulted from alternate advances of G.B.0. film and dissolution on both sides of G.B.0. film caused by the effect of electrochemical reaction. This work developed an effective approach to investigate the embrittlement process at the tip of the crack, by increasing the length of the embrittlement region through constant strain test and distinguishing the morphology and the nature of the corrosion products by optical microscopy and scanning electron microscopy (SEH).
关键词:
α-brass
,
null
,
null
,
null
谷晓鹏
,
段珍珍
,
邓钢
,
谷晓燕
材料工程
doi:10.11868/j.issn.1001-4381.2015.02.004
利用激光-MAG复合焊和MAG焊进行了厚板S355J2W+N低碳钢的焊接实验,分析了两种焊接方法接头的微观组织和力学性能.结果表明:复合焊和MAG焊焊缝接头均由焊缝区、过热区、重结晶区和不完全重结晶区构成,复合焊接头截面呈“高脚杯”状特点,焊缝填充量和热影响区宽度较MAG焊明显减小.复合焊由于冷却速率快,过热区魏氏组织略有增多,硬度高于MAG焊,抗拉强度和弯曲性能与MAG焊相比,无显著差异,均能够满足生产标准的要求.
关键词:
S355J2W+N
,
激光
,
MAG
,
复合焊
,
接头组织
,
性能
李道华
,
叶向荣
,
周益明
,
忻新泉
材料保护
doi:10.3969/j.issn.1001-1560.1999.04.002
在锌表面获得了多种不同颜色且具有金属光泽的不溶性Mo(W)-S-Zn簇合物转化膜.所获膜层具有良好的耐蚀性能和装饰效果,加热处理后颜色将发生变化,加速腐蚀试验结果表明,金黄色膜耐蚀性最佳.FT-IR、FT-Raman、XPS和AES分析表明,该膜层厚度约为60 nm.钼在膜表面的价态为+6价,而在膜内则以+6、+4价共存.从AES深度分布曲线可知,其组织为32.5%Zn,19.3%Mo,39.4%S,8.5%O.膜为多分子层组成的复杂体系,其颜色是各组分统计分布的结果.
关键词:
Mo(W)-S-Zn簇合物
,
转化膜
,
XPS
,
AES
董斌
,
祖继锋
,
高亚臣
,
宋瑛林
,
雷明凯
材料研究学报
doi:10.3321/j.issn:1005-3093.2004.06.018
用Z扫描方法测量了金属团簇化合物W2Ag4S8(dppf)2的非线性光学响应,发现团簇W2Ag4S8(dppf)2具有显著的反饱和吸收和自聚焦等非线性光学性质.应用激发态理论分析了团簇W2Ag4S8(dppf)2的非线性吸收和非线性折射,结果与实验数据一致.通过数值模拟获得激发态和基态吸收截面比值Ka及非线性折射度比值Kr,阐述了Ka和Kr的物理意义.确定了团簇W2Ag4S8(dppf)2的三阶极化率x(3).团簇化合物W2Ag4S8(dppf)2对脉宽为纳秒的激发脉冲限幅效果比较好.
关键词:
无机非金属材料
,
金属团簇化合物
,
Z扫描
,
非线性光学
,
激发态吸收
,
激发态折射
