模型毒物急性毒性尿液核磁共振氨谱标记物的二阶段聚类分析

采用现代核磁共振技术，通过分析给药肝、肾损伤模型化合物异硫氰酸α-萘酯（灌胃150mg／kg体重）和二溴乙胺氢溴酸盐（腹腔注射250mg／kg体重）24h内Wistar大鼠尿液的^1H NMR谱，由尿液中内源性代谢物浓度变化研究了肝、肾模型毒物在大鼠体内的急性毒性。首次利用模式识别技术中的二阶段聚类分析方法解析大鼠尿液^1H NMR谱确定了模型化合物尿液^1H NMR标记物。结果表明，应用核磁共振和二阶段聚类分析相结合的方法，可提供模型化合物毒性比较清楚的认识。该方法也可用于金属化合物、中药及其它药物的毒性分类和预测研究以及建议各类靶向毒性的NMR标记物。     

渗硼并两步处理硬质合金微晶金刚石涂层工具研究

研究了固体粉末渗硼并碱酸两步处理预处理硬质合金基体的表面组织、形貌、粗糙度,并在处理过的硬质合金基体上,用强电流直流伸展电弧等离子体CVD法沉积微晶金刚石薄膜涂层.进一步的涂层质量表征,附着力测试及切削实验研究结果表明,这种涂层质量高、附着力好(压痕测试临界载荷大于1500N).金刚石涂层工具的切削加工性能明显优于无涂层硬质合金工具.在加工ZAlSi12合金时,微晶金刚石涂层车刀片、铣刀片的切削寿命是无涂层车刀片、铣刀片切削寿命的32倍和26倍.     

On Occupation Times for Compound Poisson Risk Model with Two-Step Premium Rate

In this paper, we consider the classical compound Poisson risk model with two-step premium rate. Using an alternative approach, we find the explicit expressions for the Laplace transforms of joint occupation times over disjoint intervals for this model. The Laplace transforms are expressed in terms of scale functions of L\'{e}vy processes.     

LiYF4:Nd3+中脉冲光泵浦的上转换蓝光

本文报道利用578.4nm的脉冲光泵浦,在室温和77K下,观察到LiYF4:Nd3+单晶中的上转换蓝光。由发光强度与泵浦光强度平方的直线关系,确定此上转换过程是双光子过程.通过对吸收谱和激发谱以及衰减曲线的研究,确定其上转换激发机制为两步激发和能量传递上转换。     

两步投影对变分不等方程组解的迭代逼近

本文研究Hilbert空间中两步投影方法及其对变分不等方程组解具误差的迭代序列的收敛性.本文结果发展和改进了Verma等人的最新结果.     

集值非线性混合变分包含问题解的存在性及其算法

本文研究一类广义集值非线性混合变分包含问题,讨论了解的存在性,给出了逼 近解的双步迭代算法,推广统一了一些近期结果.     

New Phase-Shifting Method Using Two Images

We propose a continuous two-step method (CTSM) to obtain an image from two interference images for the measurement time reduction of optical coherence tomography. Image processing is performed for each pixel in CTSM. The calculated signal intensity has an average and standard deviation after processing since the heterodyne beat signal contains the noise in the measurements. We assume that the heterodyne beat signal contains the random noise in simulations and calculate the influence of the normalized standard deviation (NSD = standard deviation/average) on the random noise intensity for both CTSM and the conventional three-step method (TSM). We found that the NSD of the CTSM is only 1.4 times greater than that of the TSM despite processing only two images.     

Thermalization time of thin metal film heated by short pulse laser

Based on the hyperbolic two-step heat conduction model, using the Laplace transform and numerical inverse transform method (Riemann-sum approximation method), the thermal behaviour of thin metal films has been studied during femtosecond pulse laser heating. Also the thermalization time, which is the time for the electron gas and solid lattice to reach thermal balance, has been studied in detail. The values of thermalization time for silver (Ag), gold (Au), copper (Cu) and lead (Pb) are obtained. The effects of material parameters of the thin metal film on the thermalization time are considered for the four kinds of metals by changing one of the parameters and regarding the other parameters as constant. For a typical metal material, the order of the thermalization time is of the order of hundreds of picoseconds. The thermalization time decays exponentially with the increase of phonon－electron coupling factor or electron gas thermal conductivity, and it increases linearly with the increase of the ratio of lattice heat capacity to electron gas heat capacity. However, the relaxation time of the electron gas has very little effect on the thermalization time.     

Auto‐barrier‐thinning effect under rapid anodization of nanoporous alumina membrane

We have developed a rapid non‐steady anodization technique that leads to an in‐situ auto‐thinning of the barrier layer due to a space charge limited condition that modifies the local fields at the interfaces of the Al‐Al₂O₃‐electrolyte ternary system. Unlike steady‐state growth, in this non‐steady case an unequal movement of the boundaries of barrier takes place which etches the electrolyte‐oxide interface more than the oxide grows at the oxide‐metal interface, leading to a thinner barrier layer and favouring its complete removal via wet‐etching process. (© 2011 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)     

THE CLASSIFICATION OF NILPOTENT LEIBNIZ 3-ALGEBRAS

The notions of the nilpotent and the strong-nilpotent Leibniz 3-algebras are defined. And the three dimensional two-step nilpotent, strong-nilpotent Leibniz 3-algebras are classified.