基于非参数估计方法的沪铜期货价格研究

非参数估计方法是现代统计学的一个新发展方向,在各领域有重要的应用价值.本文针对非参数模型的三种估计方法,将其应用于沪铜期价与LME现价的相关关系分析,得到模型的拟合值和拟合曲线.最后,与最小二乘法的结果进行比较分析,证实了非参数估计在不同历史时期有预测精度高的优点.     

Electrochemical Study of 4-Nitrophenol at a Modified Carbon Paste Electrode

 A zeolite-modified carbon paste electrode (CPE) has been used for the determination of 4-nitrophenol by differential pulse voltammetry (DPV). The electrochemical reduction of 4-nitrophenol at −1.0 V is carried out in a Britton-Robinson medium at pH 3.5. The cyclic voltammetric (CV) behaviour has been investigated to study the nature of the process. Studies on the effect of pH were carried out over the pH range 2–9 with the Britton-Robinson buffer solution, and the influence of pH on peak height and peak potential was analyzed. A linear relationship between peak intensity and concentration is obtained in the range 0.2–10 mg L⁻¹, with a detection limit of 0.04 mg L⁻¹; a relative standard deviation of 1.5% for a 5 mg L⁻¹ 4-nitrophenol concentration and a relative error of 2.6% were also obtained (n=11). Received March 3, 1998. Revision December 10, 1998.     

铁系无铬(NBC-1)型高温变换催化剂 Ⅳ.吸附性能及CO变换反应机理的研究

通过程序升温脱附（ＴＰＤ）、程序升温表面反应（ＴＰＳＲ）及脉冲反应（ＰＳＲ）等化学物理技术,综合分析研究了铁系无铬（ＮＢＣ－１）型ＣＯ高温变换催化剂的吸附性能及化学反应特性。研究表明,ＮＢＣ－１型催化剂对Ｈ２Ｏ具有很强的吸附能力,不易吸附ＣＯ及ＣＯ２,该催化剂上水煤气变换反应的机理为氧化－还原（ｒｅｄｏｘ）反应机理     

Effects of Ar/H/N‐ion bombardment on the surface free energy and friction behavior of the fullerene‐like hydrogenated carbon (FL‐C:H) film

The surface modification of the fullerene‐like hydrogenated carbon (FL‐C:H) film was achieved by bombardment using Ar, H, and N ions, respectively. A systematic comparison of X‐ray photoelectron spectroscopy (XPS) and Fourier transformation infrared(FTIR) spectra was made between the FL‐C:H film and ion‐bombarded films. The results show that ion bombardment resulted in the increase of sp³ C content, specially, new C? N bonds were formed for N‐ion‐bombarded film. The contact angle (CA) and friction coefficient of those films were measured. The surface free energy evaluated from the contact angle increased for ion‐bombarded films, and the most obvious increase was obtained for N‐ion‐bombarded film. The friction coefficient decreased for H‐ion‐bombarded film whereas it increased for N‐ion‐bombarded film, and the friction coefficient of Ar‐ion‐bombarded film was close to that of the FL‐C:H film. Copyright © 2008 John Wiley & Sons, Ltd.     

Light scattering in the Solar System: An introductory review

We present a concise survey of light scattering by small particles in the atmospheres and surface layers of various Solar System bodies, comets, the interplanetary medium, and in planetary rings. Current issues and recent developments are emphasized. Special attention is given to experimental and numerical approaches for solving problems of light scattering by non-spherical particles. References to more detailed papers, websites and books are presented. Key areas for further research are pointed out.     

氧化亚铜产品中金属铜的分离与测定

研究了 HCl及 Sn Cl2 浓度和浸取时间对 Cu0 、Cu2 O和 Cu O浸取率的影响 ,建立了分离、测定氧化亚铜产品中金属铜的新方法 ,相对标准偏差 ( RSD) <1 .0 % ( n=6)。样品分析及误差统计结果表明 ,本方法能满足氧化亚铜产品分析的要求。     

Polymerization of Styrene by Neutral Ni (II) Acetylide Complex

Over the past few years, the utilization of late transition metal-based soluble complexes as styrene polymerization catalysts has received considerable attention1. Various systems have been explored. For example, cationic h3-allylnickel complexes alone2 or modified by P (III) ligands3 as well as a few other systems (e. g., cationic h3-benzylic nickel complexes4) are active homogeneous catalysts for the low molecular weight polymerization of styrene by simple cationic mechanism2,3,4. Neut…     

Effect of the twisted alignment on the liquid crystal wave-front corrector

The effect of twisted alignment on the phase modulation of a liquid crystal wave-front corrector was investigated. First, the effect of twisted alignment is discussed in terms of the modulation principle of the liquid crystal molecule. Only partial incident light can be modulated because of the effect of the twisted alignment. Other unmodulated light will affect the correction accuracy and the resolution of the image. The blazed grating method is proposed to solve this problem. Adaptive correction was performed without the blazed grating method and the correction results are poor. A similar adaptive correction experiment was performed with the blazed grating method and a better correction result is obtained. The residual averaged wave-front errors are PV = 0.101λ and RMS = 0.015λ and a resolvable image is obtained.     

Iridoid Glycosides from Lamiophlomis rotata

The seven new iridoid diglycosides 1 – 7 , together with eleven known iridoid and phenylpropanoid glycosides, were isolated from the 50% EtOH extract of the roots of Lamiophlomis rotata. Their structures were elucidated by chemical and spectroscopic methods.