Crystalline electric field effects on the paramagnetic susceptibility of polycrystalline materials

The paramagnetic susceptibility of polycrystalline materials having large magnetic anisotropies is considered. It is shown that polycrystalline data in many case may not reflect strong crystalline electric field phenomena, even though these are clearly seen in single crystal data.     

非线性回旋动力方程

非线性回旋动力方程是处理等离子体中非线性电磁现象及相关输运现象的有力工具.在任意磁场位形、任意频率下,建立了一套适于描述非线性电磁现象、保留有限Larmor半径(FLR)效应的、自洽的非线性回旋动力的Vlasov-Maxwell方程.     

叶绿体结构和功能的研究——叶绿体残缺膜与线粒体嵴膜组合光合磷酸化活力的重建

本文证明了类囊体残缺膜可以与线粒体嵴膜组合而成为新囊膜。这种膜组织可以通过嵴膜的偶联因子借光能来进行光合磷酸化。电子显微镜图谱显示,这种膜组织是介乎残缺膜与嵴膜之间一种膜组织。 试验结果支持了这样一种观点,即:叶绿体内光合磷酸化与线粒体内氧化磷酸化的磷酸化机构是一致的,其细胞器可能是有着共同的来源。     

The influence of small magnetic fields on the Mössbauer relaxation spectra of Au: Yb alloys

The influence of an external magnetic field on the hyperfine structure of the Γ₇ CEF ground state of dilute Yb impurities in Au is investigated through the Mössbauer effect. Strong changes in the shape of the hyperfine spectra are observed when small magnetic fields (?1 kG) are applied. The dependence of the hyperfine structure on applied magnetic fields is shown through a Breit-Rabi diagram. The electronic relaxation rate for this system is found to be independent of the fields applied. The nature of polarized radiation emitted by such sources is discussed.     

关于平面二次系统的极限环

关于常微分方程二次系统的极限环及分布结构,本文得到下述定理: 设有一个三阶细焦点,并且无限远奇点是唯一的简单的奇点,则必存在另外一个粗焦点。在粗焦点外有奇数个极限环,无限远奇点为鞍点,全局结构已定。 在上述的基础上对方程作参数的微小变化,使三阶细焦点跳出三个极限环,则得二个粗焦点,每个外面有奇数个极限环,总极限环数为偶数个,并至少为4个,全局结构已定。     

Mössbauer measurement of the hyperfine magnetic field AT sp site in Heusler alloys Rh2 Mn Z (Z=In and Sb)

We have investigated the systematics of hyperfine magnetic field on a fixed probe at the Z-site in Heusler alloys Rh₂MnZ as the valence of Z (sp element) is varied. The hmf on¹¹⁹Sn in Rh₂MnIn_.98 ¹¹⁹Sn₀₂ has been measured at 293K and 77K. In Rh₂Mn_1.12Sb_.86 ¹¹⁹Sn_.02 the hmf on¹²¹Sb has been measured at 77 K, and on¹¹⁹Sn at 293 K and 77 K. The results are compared with the hmf on¹¹⁹Sn in Rh₂Mn Ge_.98 ¹¹⁹Sn_.02 Rh₂Mn Sn, and Rh₂Mn Pb_.98 ¹¹⁹Sn_.02.Supported by the University Research Council, University of CincinnatiSupported by the Natural Sciences and Engineering Research Council of Canada     

A Mössbauer effect and X-ray diffraction study of Fe–Ga–Al thin films prepared by combinatorial sputtering

A combinatorial thin film library of the composition Fe_100−yGa_y−xAl_x was prepared by magnetron sputtering. The composition was determined by electron microprobe and showed that the Fe content was reasonably constant across the library and the Al to Ga ratio varied linearly with position. The crystallographic structure was determined with X-ray diffraction and found to be bcc. ⁵⁷Fe Mössbauer spectroscopy was used to investigate short-range order within the film. It was shown that non-magnetic atoms tend to cluster in these alloys, but that the substitution of Al for Ga reduced this tendency. This behavior may be, at least partially, responsible for the decrease in saturation magnetostriction between Fe–Ga and Fe–Al alloys.     

Synthesis and characterization of silica nanosprings by a low temperature chemical vapor deposition

Silica nanosprings were synthesized using a simple, low temperature, chemical vapor deposition method via a vapor–liquid–solid mechanism. Nanosprings with excellent uniformity and helicity in high and repeatable yields have been observed. The morphology and crystal structure of the nanosprings were characterized by scanning electron microscopy and transmission electron microscopy. The chemical composition of the nanosprings was determined using the energy-filtered transmission electron microscopic method. The as-grown nanomaterials were confirmed to be amorphous silica with irregularly shaped Au catalytic particles located at the tips. In addition, we propose a spontaneous spinning growth model to explain the formation of such helical nanostructures.