Vesicle-formation of hexadecyl phosphatidyl choline released from ε-caprolactone electrospun fibrous mats: preparation and characterization

After it was proved by transmission electron microscope and light microscope that hexadecyl phosphatidyl choline (HePC) itself and HePC/cholesterol (Chol) complexes could form micro- or nanoscale vesicles, it was also found that vesicles composed by HePC itself or HePC/Chol could be formed by releasing from the fibers after electrospun poly ε-caprolactone (PCL) fibers with hexadecyl phosphatidyl choline (HePC) and Chol entrapped was obtained. Characterization by field emission scanning electron microscope, wide-angle X-ray diffraction, and differential thermal analysis indicated that HePC and HePC/Chol was perfectly entrapped in fibers. Beside these, it is was also found that HePC and Chol presented synchronous sustained release pattern from PCL by high-performance liquid chromatography. This experiment provided a further vision of composite materials composed of macromolecule and small molecule, for application in gene delivery, controlled drug delivery and bio-scaffold.     

High pressure Raman spectra of d-threonine crystal

Raman spectra of d-threonine crystal were recorded for pressures up to 8.5 GPa. Modifications in the lattice modes indicate that the crystal undergoes two structural phase transitions, the first in the 1.9–2.4 GPa pressure range and the second in the 5.1–6.0 GPa pressure range. Splitting of modes and changes in the intensity of several bands suggest a conformational reorientation of the molecule in the crystal framework between 3.5 and 4.3 GPa. We discussed ours results by comparing with previous high-pressure investigation on l-conformer.     

A prediction of the acoustical properties of induction cookers based on an FVM–LES-acoustic analogy method

The FVM–LES-acoustic analogy method (FVM–LES-AAM), which is a hybrid prediction technique for the acoustical property computation, is presented and performed in this paper. The FVM–LES-AAM was developed by combining the finite volume method (FVM), the large eddy simulation (LES), and the Ffowcs Williams-Hawkings analogy algorithm (FWH-AA). To predict the acoustical properties of induction cookers, the FVM is used for discretizing the calculation field and building numerical equations, and the LES and FWH-AA are performed for computing the sound sources and predicting the far-field sound, respectively. Using the FVM with the unstructured grids method to discretize the control equation of Navier–Stokes was introduced for illuminating the above numerical simulation procedure. To prove the FVM–LES-AAM method is feasible for predicting the acoustical property of induction cookers, the simulated results were compared with some measured experimental data. The comparisons suggest that the hybrid method is accurate and reliable for the aeroacoustics analysis of induction cookers. Considering the temperature performance, furthermore, some new configurations for the noise reduction of induction cookers were designed, simulated, and discussed. The FVM–LES-AAM prediction technique shows promise as a feasible and computationally affordable approach for not only noise analysis of induction cookers, but also for other aeroacoustics problems in engineering.     

基于粗糙模糊集的聚类决策及应用

对基于粗糙模糊集的聚类问题进行了研究.首先,定义了粗糙模糊值与粗糙模糊集的相似度,给出了粗糙模糊集相似度的一般表达式;然后利用该公式构建了模糊相似矩阵,进而给出了粗糙模糊集的一种聚类方法;最后以实际算例说明了这种思想.     

石化废水的三维荧光光谱特征

石化废水是我国的主要工业废水之一,水量大、污染重.废水含有大量荧光物质,它的荧光光谱可以展现有机物组成,就像指纹一样与水样一一对应,被称为水质荧光指纹,简称水纹.论文通过对我国某大型石化企业的废水的三维荧光光谱特征的研究,揭示出石化废水荧光指纹丰富的特点,它含有近10个荧光峰,其中激发波长、发射波长(λex/λem)=...     

基于Logistic均匀分布图像置乱方法

针对许多基于Logistic图像置乱方法的设计只注重置乱规则和方法,没能很好地给出设计原理这一现象,文章遵循从坚实的数学理论到实际应用这一科学过程,给出了一个全新的具有坚实理论基础的基于Logistic图像置乱算法.依据混沌初值敏感性,密钥空间大这一特性,从混沌映射Logistic着手,结合概率相关理论,设计了基于Logistic映射(0,1)区间上的均匀分布随机变量产生算法,利用这一均匀分布变量生成基于位置互换的随机排列.为了度量该随机排列的置乱强度,设计了置乱强度测试算法.最后,利用这一基于Logistic均匀分布的随机排列驱动图像生成置乱图像.比较Baker算法、Ye算法和Yoon算法,结果显示,文章建议的Logistic图像置乱算法具有很大的密钥空间,很强的密钥敏感性,很强的使结构性数据相关性消失的性能,进而能够增加熵值,很好的抗攻击能力,可以有效地满足图像置乱需求. 关键词： 图像置乱 混沌序列 随机置乱 比特置乱     

同心球间流动三模类Lorenz系统的动力学行为及数值仿真

讨论了同心球间旋转流动的类Lorenz型方程组的动力学行为及其数值模拟问题,求出了该方程组平衡点,并对其稳定性进行了分析,证明了该方程组吸引子的存在性,对类Lorenz方程组的动力学行为进行了数值模拟,数值试验表明此类Lorenz型方程组存在极限环和奇怪吸引子.     

Whirl characteristics of a flexible liquid-filled rotor under thermal shock

In this paper, the whirl characteristics of a flexible liquid-filled rotor subjected to thermal shock are investigated. On the basis of the Hamilton principle, the whirl frequency equation of the rotor system is derived. Using Laplace transform, the analytical model of the temperature field of the rotor is obtained. The validity of the developed temperature model is demonstrated by comparing with the finite element results. Then, the thermal axial force exerted on the rotor is calculated and the influence factors are studied. The system stability is analyzed in terms of the whirl frequency equation. The reasonability of the predict model for system stability is verified, and a good agreement can be seen in the comparison of the obtained results based on the presented analytical method with published data. Finally, the critical spinning speed of the rotor system is analyzed, and the effects of some main parameters on system critical speed are investigated.     

Sortases from a Probiotic Lactobacillus rhamnosus GG: Cloning,Expression, Purification,Crystallization and Preliminary X-Ray Diffraction Study

Crystallography Reports - Sortases are membrane-associated cysteine transpeptidases found mainly in Gram-positive bacteria. They have been intensely studied in pathogenic strains as they play a key...