α-铁纳米线阵列的磁矩分布

在多孔阳极氧化铝(AAO)模板中, 采用电化学方法制备出α-铁纳米线阵列复合膜. 用透射Mössbauer谱(MS)、内转换电子Mössbauer 谱(CEMS)和微磁学模拟对直径为60 nm的α-铁纳米线阵列进行了内部和端面磁矩分布的研究. 透射Mössbauer 谱的结果表明, α-铁纳米线阵列内部磁矩很好地平行于纳米线长轴方向, 而内转换电子 Mössbauer 谱观察表明, 位于纳米线阵列端面, 磁矩偏离纳米线的长轴方向分布, 由二、五峰的强度计算出平均偏角为24.0°. 另外, 用微磁学模拟方法对不同深度的磁矩分布做了数值统计, 结果表明, 在纳米线内部磁矩严格地平行于纳米线轴, 越趋近两端, 平均磁矩与纳米线轴的夹角越大. 磁性测量结果表明α-铁纳米线阵列宏观磁性表现出很强的磁各向异性.     

Magnetic moment distributions in α-Fe nanowire array

α-Fe nanowire array has been electrodeposited into anodic aluminum oxide template. The magnetic moment distributions, in the interior and near the extremities of α-Fe nanowire with 60 nm in diameter, have been studied by means of transmission Mossbauer spectroscopy (MS), conversion electron Mossbauer spectroscopy (CEMS) and micromagnetic simulation. Transmission Mossbauer spectrum (MS) shows that the magnetic moments, inside the α-Fe nanowire array, are well parallel to nanowire, while conversion electron Mossbauer spectrum (CEMS) reveals that the magnetic moments, near the extremities of nanowire, diverge from the long axis of wire, and the average diverging angle calculated by the intensity ratio ofthe 2,5 peaks is about 24.0°. Moreover, the magnetic moment distributions of different depths to the top of wire are counted using micromagnetic simulation, which indicates that, the interior magnetic moments are strictly parallel to nanowire, and the closer the magnetic moment to the top of wire, the larger the diverging angle. Magnetic measurement shows that this α-Fe nanowire array represents a strong magnetic anisotropy.     

气相色谱-质谱法检测豆粉中的三聚氰胺

三聚氰胺（Melamine）是一种三嗪类含氮杂环有机化合物,是重要的氮杂环有机化工原料,简称三胺,俗称蜜胺、蛋白精。其化学性质呈弱碱性（pH8）,与盐酸、硫酸、硝酸、乙酸、草酸等均能形成三聚氰胺盐。动物长期摄入三聚氰胺会造成生殖、泌尿系统的损害,膀胱、肾部结石,并可进一步诱发膀胱癌。三聚氰胺进入人体后,会发生取代反应（水解）,生成三聚氰酸,三聚氰酸和三聚氰胺形成大的网状结构,造成结石。     

选择氧化法制备核壳NiSi/SiO_2纳米颗粒及磁学性能研究（英文）

采用选择氧化法首次制备具有核壳结构的NiSi/SiO2纳米颗粒。通过SEM,TEM,EDX,XRD和VSM等测试手段对材料进行表征。结果表明,用上述方法制备得到的NiSi/SiO2纳米颗粒直径在40~200 nm之间,SiO2壳层厚度约为20 nm。基于选择氧化、结晶和热力学理论对SiO2壳层结构的形成机理进行了阐释。制备得到的NiSi/SiO2纳米颗粒在室温下显示出超顺磁性。     

Magnetic moment distributions in a-Fe nanowire array

With the developing requirement of magnetic recording density, perpendicular magnetic re-cording is an important approach and attracts considerable interest[1,2]. In perpendicular magnetic recording technology, it is expected that the preferred direction of magnetization and magnetic moments are perpendicular to the disk, high remanence, high coercivity and small size are also demanded for the magnetic recording elements[3]. Recently, people have electrodeposited mag-netic metal nanowires into…     

马氏体钢表面磁控溅射类金刚石薄膜滚动接触疲劳失效机理

采用磁控溅射技术在马氏体钢基体表面制备类金刚石(DLC)薄膜,应用扫描电镜、Raman光谱仪和划痕测试仪等对薄膜进行表征. 基于对失效表面及截面微观特征的详细分析,研究了DLC薄膜在接触疲劳载荷下的失效特征和机理. 结果表明:DLC薄膜试样的滚动接触疲劳(RCF)寿命比基体的寿命显著提高,且薄膜磨损后试样的剩余寿命仍比原基体寿命长. 薄膜厚度3 μm,处于接触最大应力分布的15 μm范围内. DLC薄膜是从基体表面粗糙峰处产生微裂纹进而导致薄膜剥落,基体材料裸露,最终试样失效.