混合模型中方差分量估计的容许性及非负估计

对含有两个方差分量的线性混合模型, 本文构造了方差分量的一个线性估计类, 它包含许多常见的方差分量估计. 在这个类中我们建立了容许性的必要条件, 据此得到了两个新的改进估计. 最后我们讨论了方差分量的非负估计, 得到了优于方差分析估计和Tatsuya估计的正估计.     

反应挤出聚烯烃接枝改性研究进展

聚烯烃通过接枝改性可以有效地扩大其应用范围。本文简介了近几年反应挤出中聚烯烃接枝体系的组成和接枝机理，讨论了影响因素及其存在的副反应，同时介绍了接枝产物在增容改性等方面的应用。     

面向等离子体部件沉积特性的数值模拟研究

采用粒子模拟研究方法，利用PEGASUS 程序对等离子体环境下面向等离子体部件的沉积特性进行了模拟研究。结果显示部件表面连接缝隙尺寸、表面粗糙度、粒子入射的角度以及流量对沉积影响显著。在能量较小、溅射可忽略时，能量对沉积的影响很小。粗糙度越小，沉积量越小；同一种粗糙度，不同轮廓也会使沉积发生较大变化，轮廓一致的更有利于减小沉积。该模拟对研究等离子体与材料相互作用，分析瓦片缝隙尺寸、瓦片加工工艺和等离子体参数对面向等离子体部件沉积行为的影响具有重要意义。     

Highly stereo and chemoselective synthesis of tetra and pentacyclic frameworks using Solid-State Melt Reaction (SSMR)

Benzopyran fused tetra and pentacyclic frameworks have been synthesized by the domino Knoevenagel hetero Diels–Alder (DKHDA) reaction using various 1,3-diones with O-allylated salicylaldehydes and O-propargylated salicylaldehydes in a solvent and catalyst free condition via Solid-State Melt Reaction (SSMR). The reaction requires only a single step operation thus providing potentially bioactive polycyclic heterocycles in high yields.     

Application of high‐surface‐area graphitized carbon black with primary secondary amine as an alternative quick,easy, cheap,effective, rugged,and safe cleanup material for pesticide multi‐residue analysis in spinach

A multi‐residue method has been developed and validated to determine 46 pesticides in spinach using liquid chromatography tandem mass spectrometry. The method is based on modified quick, easy, cheap, effective, rugged, and safe sample preparation, where high‐surface‐area graphitized carbon black was used first as sorbent material in the dispersive solid‐phase extraction. The method was compared with the quick, easy, cheap, effective, rugged, and safe method. The morphology, surface area, pore size, and pore volume of the sorbent was determined. The results obtained show that the sorbent consists of high surface area (233 m²/g) and large pore volume (1.5 cm³/g). The calibration curve correlation coefficient (R²) of the method was at least 0.99. The average recoveries ranged from 74 to 116%, and limits of detection and quantification from 0.0001 to 0.002 mg/kg and from 0.0002 to 0.005 mg/kg, respectively. Using the method, the pesticides exhibited low matrix effect (< 20%), except for nicosulfuron (29.86%), methomyl (26.77%), and flufenoxuron (24.65%). The method showed better potential to remove pigments than the quick, easy, cheap, effective, rugged, and safe method. It is demonstrated that the proposed method could be useful alternative for sample preparation of spinach and other matrices in future.     

Analysis of questioned documents: A review

During the last years (2000–2014), many publications concerning the forensic analysis of questioned documents have been published, and new techniques and methodologies are nowadays employed to overcome forensic caseworks. This article reviews a comprehensive collection of the works focused on this issue, including dating studies, the analysis of inks from pens and printers, the analysis of paper, the analysis of other samples related to questioned documents and studies on intersecting lines. These sections highlight the most relevant analytical studies by a wide range of analytical techniques. Separation and spectrometric techniques are critically discussed and compared, emphasizing the advantages and disadvantages of each one. Finally, concluding remarks on the research published are included.     

等厚条纹对比度与暗背景光学元件

本文讨论了影响等厚条纹对比度的原因，指出了暗背景光学元件的优点。     

Simultaneous determination of ginsenoside Rb1, ginsenoside Rg1, paeoniflorin,albiflorin and oxypaeoniflorin in rat plasma by liquid chromatography–tandem mass spectrometry: Application to a pharmacokinetic study of wen‐Yang‐Huo‐Xue soft capsule

A simple and sensitive HPLC–MS/MS method was developed and fully validated for simultaneous determination of ginsenoside Rb1, ginsenoside Rg1, paeoniflorin, albiflorin and oxypaeoniflorin in rat plasma. Plasma samples were pretreated with protein precipitation using acetonitrile. The chromatographic separation was carried out on a C₁₈ column with a gradient mobile phase consisting of acetonitrile and water (containing 0.1% formic acid). All analytes and digoxin (internal stand, IS) were quantitated through electrospray ionization in negative ion multiple reaction monitoring mode. All calibration curves exhibited good linearity (r > 0.9960) over a wide concentration range for all components. The intra‐day and inter‐day precisions (RSD) at three different levels were all <12.0% and the accuracies (RE) ranging from −6.1 to 6.2%. The extraction recoveries of the five compounds ranged from 89.2 to 97.1%. The validated method was successfully applied in a comparative pharmacokinetic study of Wen‐Yang‐Huo‐Xue soft capsule (WYHXSC) in rats. Compared with single pure component, the exposure of the investigated components, except for oxypaeoniflorin, increased after oral administration of WYHXSC in rats, which suggested a synergistic effects between the herbs in the WYHXSC preparations.