The crystallization process of a−Fe35Ni15B26 ultrafine particles produced by reduction with borohydride

The crystallization process of a?Fe₃₅Ni₁₅B₂₆ ultrafine alloy particles prepared by chemical reduction with borohydride was investigated mainly by Mössbauer spectroscopy. The experimental results exhibit some new characteristics which were attributed to the microstructure of the sample.     

Carbon-supported iron catalysts: Iron-57 Mössbauer spectroscopic studies of phase formation and dispersion properties which influence catalytic performance

The treatment of carbon-supported iron in hydrogen and carbon monoxide gives the formation of iron carbide phases, the nature of which depends on the degree of dispersion of the supported iron phase. The carbon-supported iron catalysts show high activity, low conversion to methane, and good selectivities for the formation of gaseous olefins and liquid hydrocarbons. The catalytic performance is associated with strong interactions between the carbon support and the metallic iron particles as revealed by⁵⁷Fe Mössbauer spectroscopy. The results imply that the carbon may not only function as a support for the dispersion of iron, but that electron movement to the iron/carbon interface influences catalytic performance.     

GaAs非对称X结波导混合耦合器的研究

本文报道了ＧａＡｓ非对称Ｘ结波导耦合器的工作原理。该器件制作在ｎ＾－／ｎ＾＋ＧａＡｓ外延材料上。文中采用有效折射率法分析了这个耦合器的分离角、波导脊高及其两个非对称波导传播常数差之间的关系。器件在λ＝１．１５μｍ下测量，得到了小于－２．９ｄＢ的分光性能和小于－２０ｄＢ的串音比。     

The characterization of iron based Fe−M ultrafine particle (UFP) catalysts. II. Effect of second metal component (M=Mn,Zn, Mg)

The effect of second metal component on the structural characteristic of Fe M UFP catalysts was investigated by in situ Mossbauer spectroscopy. The incorporation of second metal component hinders, the reduction and carburization of iron containing phase in the presence of H₂ and CO, and the degree of hindrance is in the order of Mg Mn Zn due to the interaction between iron and the second metal component. Consequently, the formation of light olefinic products is in the order of Fe Mg>Fe−Mn·Fe−Zn catalysts consistent with the F-T synthesis performance. This work was supported by the National Natural Science Foundation of China     

测定大气颗粒物中金属含量的样品预处理

通过综合对比实验，从多种样品预处理方法中筛选出测定大气颗粒物中金属含量的样品预处理方法——HNO3-HClO4热消解提取法。该法操作简便、易于掌握，待测金属及其化合物提取率达90%以上（滤筒样品84%以上），而且空白值低，可与化学法及仪器法配套使用。     

Simultaneous determination of eight bioactive constituents of Zhi‐Zi‐Hou‐Po decoction in rat plasma by ultra high performance liquid chromatography with tandem mass spectrometry and its application to a pharmacokinetic study

Zhi‐Zi‐Hou‐Po Decoction, consisting of Gardenia jasminoides Ellis, Magnolia officinalis Rehd. et Wils., and Citrus aurantium L, is a classical Traditional Chinese Medicine formula for the treatment of depression. In order to make good and rational use of this formula in the future, a sensitive, selective, and reliable ultra high performance liquid chromatography with tandem mass spectrometry method was developed for simultaneous determination of two iridoid glycosides (geniposide and genipin gentiobioside), two lignans (honokiol and magnolol), four flavonoid glycosides (isonaringin, naringin, hesperidin, and neohesperidin), the major bioactive constituents of Zhi‐Zi‐Hou‐Po Decoction, in rat plasma using paeoniflorin as internal standard. Plasma samples were pretreated by a simple protein precipitation with acetonitrile. Chromatographic separation was performed on a shim‐pack XR‐ODS C₁₈ column (75 × 3.0 mm, 2.2 µm) using gradient elution with mobile phase consisting of 0.1% formic acid aqueous solution and acetonitrile at a flow rate of 0.5 mL/min. Mass spectrometric detection was conducted on a 3200 QTRAP mass spectrometry equipped with electrospray ionization source in negative ionization mode. Quantification was performed using multiple reactions monitoring mode. Calibration curves exhibited good linearity (r > 0.9947) over a wide concentration range for all analytes, and the lower limits of quantification were 10, 5, 1, 5, 1, 5, 1, and 5 ng/mL for geniposide, genipin gentiobioside, honokiol, magnolol, isonaringin, naringin, hesperidin, and neohesperidin, respectively. The intraday and interday precisions at three quality control levels were less than 12.3% and the accuracies ranged from ?11.2 to 10.7%. Extraction recovery, matrix effect, and stability were satisfactory in rat plasma. The validated method was successfully applied to a pharmacokinetic study of the eight analytes after oral administration of Zhi‐Zi‐Hou‐Po decoction to rats.     

Long distance real-time measurement of multi-points micro-vibration in region by digital holography

Many applications require micro-vibration measurement, especially multi-points detection at long distance in real-time. In this paper, a micro-vibration measurement approach based on digital holographic interferometry is proposed for middle-low frequency detection. It can be used to monitor irregular frequency/amplitude vibration in selected region over 10 m away simultaneously and synchronously. A series of experiments were conducted including real-time measurement of 300 Hz, 1 kHz, 2 kHz and 3 kHz constant frequency/amplitude periodic vibration, precision and frequency response tests with calibration of LDV, 1 kHz irregular amplitude vibration, irregular frequency/amplitude vibration as well as the real-time measurement and simultaneous display of multi-points vibration. The experimental results demonstrate the feasibility of the proposed method and reveal its unique advantages.     

State-to-state quantum dynamics of the H((2)S) + O2(ã(1)Δ(g)) → O((3)P)+OH(X(2)Π) reaction on the first excited state of HO2(Ã(2)A')

State-to-state differential and integral cross sections for the title reaction were calculated using an exact wave packet method on a recently developed ab initio potential energy surface of the first excited state HO(2)(?(2)A'). The calculation results indicate that the reaction is dominated by highly rotationally excited OH products scattered in both the forward and backward directions, consistent with the formation of a long-lived HO(2) reaction intermediate. However, a statistical model was found to overestimate the integral cross sections, due apparently to dynamical bottlenecks. In addition, a unique feature in the OH + O exit channel potential promotes rotational excitation of the departing OH product by exerting a torque force. The role of the title reaction in high temperature combustion is also discussed.     

黎曼流形上一类指数调和型热方程的梯度估计

本文我们推到了黎曼流形上指数调和型热方程的一个Hamilton-Souplet-Zhang型梯度估计. 利用这个估计, 我们得到了一个Liouville型定理.     

焙烧温度对Mg(Al)O复合物结构和表面酸碱性质影响的研究

分别在６７３。８７３和１０７３Ｋ分解Ｍｇ／Ａｌ摩尔经继３的水滑石生成Ｍｇ（Ａｌ）Ｏ复合物，ＸＲＤ测定均ＭｇＯ物相，８７３Ｋ以上焙烧的样品同时存在ＭｇＡｌ２Ｏ４尖晶石物相，微量吸附量热测定其表面酸碱中心的强度和密度，发现碱中心强度和密度顺序为ＭＡＯ－２〈ＭＡＯ－３≈ＭＡＯ－１，而酸中心强度和密度顺序是：ＭＡＯ－１〉ＭＡＯ－３≈ＭＡＯ－２，红外光谱表明，Ｍｇ（Ａｌ）Ｏ复合物表面酸碱中心主要存在Ｌ酸，碱