Ultrafine grain formation and coating mechanism arising from a blast coating process: A transmission electron microscopy analysis

This article examines the substrate/coating interface of a coating deposited onto mild steel and stainless steel substrates using an ambient temperature blast coating technique known as CoBlast. The process uses a coincident stream of an abrasive blast medium and coating medium particles to modify the substrate surface. The hypothesis for the high bond strength is that the abrasive medium roughens the surface while simultaneously disrupting the passivating oxide layer of the substrate, thereby exposing the reactive metal that then reacts with the coating medium. The aim of this study is to provide greater insight into the coating/substrate bonding mechanism by analysing the interface between a hydroxyapatite coating on both mild and stainless steel substrates. The coating adhesion was measured via a tensile test, and bond strengths of approximately 45 MPa were measured. The substrate/coating interface was examined using transmission electron microscopy and selected area diffraction. The analysis of the substrate/coating interface revealed the presence of ultrafine grains in both the coating and substrate at interface associated with deformation at the interface caused by particle impaction during deposition. The chemical reactivity resulting from the creation of these ultrafine grains is proposed to explain the high adhesive strength of CoBlast coatings.     

Drug–Membrane Interaction on Immobilized Liposome Chromatography Compared to Immobilized Artificial Membrane (IAM), Liposome/Water,and Octan‐1‐ol/Water Systems

The objective of this study was to investigate drug–membrane interaction by immobilized liposome chromatography (ILC; expressed as lipophilicity index log K_s) and the comparison with lipophilicity indices obtained by liposome/H₂O, octan‐1‐ol/H₂O, and immobilized artificial membrane (IAM) systems. A set of structurally diverse monofunctional compounds and drugs (nonsteroidal anti‐inflammatory drugs and β‐blockers) were selected in this study. This set of solutes consists of basic or acidic functionalities which are positively or negatively charged at physiological pH 7.4. No correlation was found between log K_s from ILC and lipophilicity indices from any of the other membrane model systems for the whole set of compounds. For structurally related compounds, significant correlations could be established between log K_s from ILC and lipophilicity indices from IAM chromatography and octan‐1‐ol/H₂O. However, ILC and liposome/H₂O systems only yield parallel partitioning information for structurally related large molecules. For hydrophilic compounds, the balance between electrostatic and hydrophobic interactions dominating drug partitioning is different in these two systems.     

反射转镜式干涉光谱仪光程差的一般表达式

对反射转镜式干涉光谱仪的原理进行了介绍,从马吕斯定律和角反射体的反射特性入手,选择转镜反射面的旋转中心作为入射光束和出射光束等波面的参考点,对反射转镜式干涉光谱仪的光程差进行了分析计算,给出反射转镜式干涉光谱仪任意时刻光程差及最大光程差的一般表达式,分析影响最大光程差和光程差变化周期的因素,为反射转镜式干涉光谱仪的设计与研制提供理论指导。     

转镜式光谱仪光程差和非线性的研究

对转镜式高速干涉光谱仪的基本原理进行了介绍,给出了无晃动和有晃动两种情况下,轴上和轴外光线的光程差公式,并对结果进行了初步分析,发现晃动将使光程差大小发生变化,但不改变轴上光线零光程差的位置.光程差的非线性是转镜式干涉仪的天生缺陷,它和转镜的折射率、工作角等参量有关,使非线性最小可得出最佳折射率为2.9左右,从光程差误差的容限可以计算出对工作角的要求,折射率为最佳时,工作角可达13.3°,根据对非线性的分析结果,给出了转镜主要参量选择的原则.     

Highly sensitive and selective sensing platform based on π–π interaction between tricyclic aromatic hydrocarbons with thionine–graphene composite

We are just beginning to exploit the fascinating potential of thionine, called electrochemical probe that can selectively recognize specific polycyclic aromatic hydrocarbons (PAHs), as tools for the detection of tricyclic aromatic hydrocarbons phenanthrene (PHE) and anthracene (ANT). A novel electrochemical sensing platform by modification of electroactive thionine functionalized graphene onto glass carbon electrode (Th/GRs/GCE) surface was constructed. The immobilized thionine showed a remarkable stability, which may benefit from the π–π stacking force with graphene. Under optimum conditions, the proposed electrochemical sensor exhibited high sensitivity and low detection limit for detecting PHE and ANT. The total amount of PHE and ANT could be quantified in a wide range of 10 pM–0.1 μM with a good linearity (R² = 0.9979) and a low detection limit of 0.1 pM (S/N = 3). Compounds which possess one or two benzene rings or PAHs with more than three rings, such as benzene, naphthalene (NAP), benzo[a]pyrene (BaP) and pyrene (PYR) show little interference on the detection. Consequently, a simple and sensitive electrochemical method was proposed for the determination of PHE and ANT, which was used to determine PHE and ANT in waste water samples. The electrochemical method provides a general tool that complements the commonly used spectroscopic methods and immune method for the detection of PAHs.     

全对称傅里叶透镜的设计

本文研究了傅里叶透镜的设计,并叙述了一种对称型傅里时变换透镜.在相对孔径1:10时,输入面和频谱面处的象质均较好.傅里叶交换透镜的特点是必须对两对物象共轭位置(即位于前焦面处的输入面和位于后焦面处的频谱面)控制除畸变以外的全部象差.1969年后开始出现的傅里叶变换透镜,多属6～8片的对称或近似对称的四组元双远距型,本文叙述了一种严格对称型四片傅里叶交换透镜.     

从头计算方法对聚乙炔热异构的研究

用STO-3G从头计算方法对具有准一维链的顺-反式聚乙炔的热异构进行了研究．在总结大量实验事实的基础上,采用热异构的双极缺陷模型,计算了顺-反式C_(10)H_(12)体系绕C=C双键旋转的情况下,体系总能E_(Tot)与旋转角(?)的变化关系,以及这种热异构过程中各种构型的能量值和相对差值．模拟了双极缺陷沿链的移动过程,得到从顺-反式到反-顺式聚乙炔过渡的能垒约0.6eV．从理论上证明了在室温下,仍可通过热激活实现顺-反式到反-顺式再到反式的异构转变,同时也得出当产生一个双极缺陷时,体系的自旋数增加1,很好地解释了电子自旋共振(ESR)实验发现的热异构使聚乙炔自旋增加的事实。     

基于空间特征的光谱分类算法研究

随着成像光谱仪器的广泛应用,利用数据立方体进行物质分类与识别成为一项重要的研究内容,分类算法对最终的目标识别准确度与精度具有很大的决定作用。目前常见的分类算法主要利用了光谱维信息,从光谱匹配的角度进行物质分类。由于仪器探测的物质反射光谱不仅反映了物质种类,还与物质表面的几何结构,表面粗糙度等有关,因此仅仅利用物质的反射光谱进行物质分类识别具有一定的误差。该文在利用可见光反射光谱进行分类的基础上,结合图像空间特征,对分类过程进行控制,达到提高分类准确度的目的。利用该分类算法进行真假叶片识别,结果表明其具有较好的空间连续性,很大程度上克服了"麻点"效应,验证了算法的有效性。     

An empirical study on information spillover effects between the Chinese copper futures market and spot market

This study employs a parametric approach based on TGARCH and GARCH models to estimate the VaR of the copper futures market and spot market in China. Considering the short selling mechanism in the futures market, the paper introduces two new notions: upside VaR and extreme upside risk spillover. And downside VaR and upside VaR are examined by using the above approach. Also, we use Kupiec’s [P.H. Kupiec, Techniques for verifying the accuracy of risk measurement models, Journal of Derivatives 3 (1995) 73-84] backtest to test the power of our approaches. In addition, we investigate information spillover effects between the futures market and the spot market by employing a linear Granger causality test, and Granger causality tests in mean, volatility and risk respectively. Moreover, we also investigate the relationship between the futures market and the spot market by using a test based on a kernel function. Empirical results indicate that there exist significant two-way spillovers between the futures market and the spot market, and the spillovers from the futures market to the spot market are much more striking.     

Gradient-based iterative identification for Wiener nonlinear systems with non-uniform sampling

This paper focuses on the identification problem of Wiener nonlinear systems with non-uniform sampling. The mathematical model for the Wiener nonlinear system is established from the non-uniformly sampled input–output data. In order to solve the identification problem of the Wiener nonlinear system with the unmeasurable variables in the information vector, the gradient-based iterative algorithm is presented by replacing the unmeasurable variables with their corresponding iterative estimates. Finally, the simulation results indicate that the proposed algorithm is effective.