一种提高油样中低含量石油磺酸盐分析效率的方法

为了准确分析油田化学驱采出液油样中石油磺酸盐的含量,介绍了一种在油样中加入不同极性溶剂组成的萃取体系的预处理技术,将石油磺酸盐萃取到水相,利用液相色谱仪对其进行检测的方法。取适量油样,依次加入正己烷、二氯甲烷、无水乙醇和蒸馏水,振荡均匀后静置分层,取下层水相溶液进行色谱分析。色谱柱为阴离子交换柱,流动相为甲醇/水和甲醇/盐水(含0.2 mol/L乙酸和0.2 mol/L乙酸铵),梯度洗脱。实验结果表明,该预处理技术联合液相色谱法检测技术分析效率较高,加标回收率高于90%,液相色谱最小定量限10 mg/L,线性范围10～2000 mg/L。该方法可对油样中低含量的石油磺酸盐进行快速定量分析。     

Grain growth kinetics and growth mechanism of columnar Al2O3 crystals in xNb2O5–7.5La2O3-Al2O3 ceramic composites

xNb₂O₅–7.5La₂O₃-Al₂O₃ ceramic composites with in-situ-grown columnar Al₂O₃ crystals were successfully prepared by microwave sintering at 1450–1525?°C using α-Al₂O₃, Nb₂O₅, and La₂O₃ powders as raw materials. X-ray diffraction results indicated that the main phases were Al₂O₃, LaNbO₄, and Nb₂O₅ in the prepared samples. A field emission scanning electron microscope (FESEM) showed that the Al₂O₃ crystals appeared as columnar in the structure. Moreover, the grain size of the columnar Al₂O₃ crystals increased with the Nb₂O₅ content. The ratio of the major axis to the minor axis of the crystals was largest when the Nb₂O₅ content was 15?vol%. Furthermore, the grain-growth kinetics index (n), growth activation energy (Q), and growth mechanism of the columnar Al₂O₃ crystals were studied. The results indicated that the Nb₂O₅ addition could promote formation and growth of columnar Al₂O₃ crystals, and the grain-growth activation energy indicated that the dissolution process controls the crystal growth. The growth mechanism of the columnar Al₂O₃ crystals was also studied. The present work demonstrated that Nb₂O₅ is a good additive for the preparation of Nb₂O₅–7.5La₂O₃-Al₂O₃ composite ceramics with columnar Al₂O₃ crystals.     

用气相色谱法检测顺酐生产中间物料组分

顺酐在常温下是固体,要制备成溶液才能进行气相色谱分析,所以溶剂的选择极为重要。为此,选用了稳定性好、沸点较高的乙腈作为溶剂,利用超声溶解,对生产中粗酐样品进行采样分析,并建立了气相色谱法测定顺酐中杂质含量的分析方法,可有效指导顺酐生产过程中的杂质组分分离,适用于顺酐生产的现场工艺控制。     

An Artificial Nocturnal Flower via Humidity‐Gated Photoactuation in Liquid Crystal Networks

Beyond their colorful appearances and versatile geometries, flowers can self‐shape‐morph by adapting to environmental changes. Such responses are often regulated by a delicate interplay between different stimuli such as temperature, light, and humidity, giving rise to the beauty and complexity of the plant kingdom. Nature inspires scientists to realize artificial systems that mimic their natural counterparts in function, flexibility, and adaptation. Yet, many of the artificial systems demonstrated to date fail to mimic the adaptive functions, due to the lack of multi‐responsivity and sophisticated control over deformation directionality. Herein, a new class of liquid‐crystal‐network (LCN) photoactuators whose response is controlled by delicate interplay between light and humidity is presented. Using a novel deformation mechanism in LCNs, humidity‐gated photoactuation, an artificial nocturnal flower is devised that is closed under daylight conditions when the humidity level is low and/or the light level is high, while it opens in the dark when the humidity level is high. The humidity‐gated photoactuators can be fueled with lower light intensities than conventional photothermal LCN actuators. This, combined with facile control over the speed, geometry, and directionality of movements, renders the “nocturnal actuator” promising for smart and adaptive bioinspired microrobotics.     

Strain rate and orientation-dependent strain hardening of Mg–9Li–Al using crystal plasticity

A crystal plasticity finite element model was proposed considering slip and twinning interactions. The grain morphology and crystallographic orientations were introduced into the model to describe the microstructure of duplex polycrystalline Mg–9Li–Al. The activation of the slip systems and the strain localisation with respect to initial grain orientations were investigated. In addition, the effects of phase distributions and volume fractions on the macroscopic responses and on strain hardening rates were analysed. The results show that the strain hardening is rate-dependent but the texture is less sensitive to strain rate. The distribution of a phase and its volume fraction play primary roles in governing the mechanical response.     

What is a crystal to the new chemical crystallographer,after that first,automated structure analysis?

This educational review postulates the importance of maintaining an adequate level of crystallographic education among structure-dependent scientists whose interests are not primarily in crystallography, at a time when automation and validation have made it possible to obtain high-quality structure analyses in many cases with a minimum of crystallographic background. The topics addressed are intended to form a second round of crystallographic education for a novice user whose first round involved hands-on experience with structure solution and an introduction to elementary concepts. The specific topics, chosen for their relevance as basic knowledge and their lack of emphasis in many formal treatments, are (1) crystallographic reference frames and the utility of the reciprocal cell in geometrical calculations; (2) the relationship between the two concepts that constitute our model of the crystal, namely the unit cell and the lattice; (3) the manner in which an atom is represented in concept and in practice; (4) the importance of interleaved symmetry elements required by the presence of additional symmetry on a lattice; (5) the harnessing of the natural properties of the crystalline state for the potential manipulation of properties of synthetic crystals; and (6) useful terminology for navigating a crystal structure.     

Prediction of the water content of biodiesel using ANN-MLP: An environmental application

Fuel quality, especially biodiesel, is highly dependent on its water content, and the major sources of water in the fuel relate to the transportation, production, and storage processes. In this present contribution, the multilayer perceptron artificial neural network (MLP-ANN) was applied to predict the water content of biodiesel and diesel blend in terms of temperature and composition. The proposed algorithm was trained and tested by utilizing 400 experimental data points which were extracted from the literature. Based on the results, the MLP-ANN model has great ability to estimate the water content of biodiesel and diesel blend. The R-squared (R²), root mean square error, average absolute relative deviation, and a?bsolute deviation parameters for the total data set are obtained, respectively, as 0.99784, 123919.1172, 3.3632, and 1.17%, which indicate the effective performance suggested by ANN. As the computational study is cheaper and easier than the experimental study, the developed software could be considered as an alternative for laboratory study, and the environmental effect of biodiesel and produced undesired product after biodiesel combustion which is directly related to the water content of biodiesel is estimable with the information released in this study.     

A series of Er~(3+)-activated SrLaGa_3O_7 single crystal fibers for mid-infrared laser application

A multidisciplinary approach for the production and characterization of a series of high concentration Er~(3+)activated SrLaGa_3 O_7(abbreviated as Er:SLGO) crystal fibers is shown to have a great promise for implementation in mid-infrared laser applications.The current approach includes the design and formation of unique layered tetrahedral network structures with several kinds of rare earth(RE) ions including Er ions distributing statistically between layers,such as Er:SLGO,Er,Nd:SLGO,Er,Yb,Ho:SLGO,Er,Eu:SLGO and Er,Ho:SLGO.Five kinds of Er:SLGO crystal fibers were designed to grow via a micropulling down method.Spectroscopic analyses show that Er,Yb,Ho:SLGO and Nd,Er:SLGO crystal fibers were superiorly endowed with inhomogeneous broadening absorption and strong emission.The unique structural components design enables the generation of improved absorption and emission recombination,and the inhibition of self-termination as well.Generally,the use of structural components design may warrant high-efficiency emissions in RE-doped crystal fibers.     

基于加权法的砾类土含水率检测

砾类土在工程建设中有着广泛的应用,其含水率是一项非常重要的指标,但现有测试方法耗时较长。以砂砾石料的砾类土为试验对象,基于加权法思想,将饱和面干含水率替代法和虚拟比重法进行结合,开展砾类土含水率快速检测方法的研究,并对现有的饱和面干含水率测定操作进行一定的改进和优化。采用多种数学方法(绝对误差、均方偏差平方和,相关曲线的相关系数和F显著性检验分析法)对加权法和烘干法的结果进行对比分析。通过试验统计数据分析,证实加权法与烘干法的测定结果基本一致。该分析结果为现场土料含水率快速测定提供了一种新的思路和手段。