金红石TiO2(011)表面的理论研究进展

基于密度泛函理论 (DFT) 的第一性原理 (First-principles) 计算方法，就金红石TiO₂(011)表面在理论方面的研究进展做了介绍.首先，通过阐述研究金红石TiO₂(011)表面的必要性和实验在其结构方面的研究进展，介绍了金红石TiO₂(011)表面的电子结构和光学性质，指出并验证了该表面对可见光有较强的响应能力.随后，介绍了金红石TiO₂(011)表面的缺陷和杂质，指出吸附H原子和形成O缺陷后还能显著增强其在红外区的红外吸收.在此基础上，不仅从理论上提供了一些传统实验所无法提及的数据资料，还弥补了相关实验在微观领域研究中的不足.最后，就目前金红石TiO₂(011)表面研究中存在的问题做了展望，指出金红石TiO₂(011)表面各种表面现象的微观本质是未来研究的重点内容.     

Enhanced performance of nano-sized SiC reinforced Al metal matrix nanocomposites synthesized through microwave sintering and hot extrusion techniques

In the present study, nano-sized SiC (0, 0.3, 0.5, 1.0 and 1.5 vol%) reinforced aluminum (Al) metal matrix composites were fabricated by microwave sintering and hot extrusion techniques. The structural (XRD, SEM), mechanical (nanoindentation, compression, tensile) and thermal properties (co-efficient of thermal expansion- CTE) of the developed Al-SiC nanocomposites were studied. The SEM/EDS mapping images show a homogeneous distribution of SiC nanoparticles into the Al matrix. A significant increase in the strength (compressive and tensile) of the Al-SiC nanocomposites with the addition of SiC content is observed. However, it is noticed that the ductility of Al-SiC nanocomposites decreases with increasing volume fraction of SiC. The thermal analysis indicates that CTE of Al-SiC nanocomposites decreases with the progressive addition of hard SiC nanoparticles. Overall, hot extruded Al 1.5 vol% SiC nanocomposites exhibited the best mechanical and thermal performance as compared to the other developed Al-SiC nanocomposites.     

ePTFE人工血管管壁结构及其体外性能的试验研究

对国内外两组膨体聚四氟乙烯(ePTFE)人工血管从管壁结构、理化性能和生物力学性能进行对比研究.通过试验研究两组人造血管管壁的宏观及微观结构、表面润湿性、结晶度和融熔温度、周/轴向拉伸、顶破拉伸以及手术线固位强力,对比两组样品的性能差异,并分析了导致差异的可能原因,讨论了管壁结构、理化性能与力学特性之间的关系.研究结果表明,国产和进口ePTFE人工血管试样均为双层结构,两者都有良好的疏水性表面和抗水渗透性.但进口试样具有更加规整均匀的节点和纤维形态结构,有利于人工血管的生物耐久性.     

渗碳体形态对高碳珠光体钢组织及性能的影响

为研究SWRS82B钢不同条件下进行的大过冷工艺所形成的渗碳体形态对珠光体亚结构组织及性能的影响,制定相关热处理工艺:将试样在880℃奥氏体化15 min后,以70,100,200℃/s的冷速过冷到300℃等温3~15s,之后升温至珠光体区等温1min,最后快冷至室温.通过SEM和TEM观察,以及MTS拉伸试验机得到的数据,结果表明,在过冷时间为3s的前提下,随着冷速的增长,渗碳体由完整片层状发生不同程度的碎化.在200℃/s时,渗碳体已经大面积碎化,并发现大量的纳米级渗碳体,抗拉强度表现为先降低后升高,伸长率持续升高.当冷却速度为70℃/s时,随着过冷时间的延长,抗拉强度和伸长率都表现为先降低后增大的特点.纳米渗碳体随着过冷时间的延长开始减少,到达15s时,开始出现了贝氏体组织.     

木枣多糖的理化特性研究

木枣经超声波辅助酸性缓冲液浸提、醇沉、脱蛋白和脱色工艺制得木枣多糖,测定其溶解性与单糖组成,采用Q2000型差示扫描量热仪和ZX7M-AR1000型流变仪研究木枣多糖的稳定性和流变性,为其在食品工业中的应用提供理论数据支持。实验结果表明,木枣多糖溶于热水,难溶于冷水,不溶于有机试剂；是由鼠李糖、阿拉伯糖、甘露糖、葡萄糖、半乳糖组成的杂多糖。热学特征分析表明木枣多糖具有较好的热稳定性；木枣多糖溶液为非牛顿假塑性流体,表现出剪切变稀的特性；因此木枣多糖适用于在食品生产工业中做稳定剂。     

改性化工污泥与煤的成浆性及燃烧性分析

选取两种方法对化工污泥进行改性并研究改性后的污泥添加量对污泥水煤浆(S-CWS)成浆性、流变性和燃烧性的影响,从而获得制备高浓度污泥水煤浆的工艺参数.结果表明:选用Na OH对污泥进行改性制备出的污泥水煤浆成浆性较好;改性污泥添加量在10%~20%,可以得到成浆性良好的污泥水煤浆;添加改性污泥的污泥水煤浆较普通水煤浆的燃烧性能增加.     

Effect of Graphene Nanoplatelets addition on mechanical properties of pure aluminum using a semi-powder method

In recent years, graphene has attracted considerable research interest in all fields of science due to its unique properties. Its excellent mechanical properties lead it to be used in nano-composites for strength enhancement. This paper reports an Aluminum–Graphene Nanoplatelets(Al/GNPs)composite using a semi-powder method followed by hot extrusion. The effect of GNP nano-particle integration on tensile, compressive and hardness response of Al is investigated in this paper. It is demonstrated that 0.3 wt% Graphene Nanoplatelets distributed homogeneously in the matrix aluminum act as an effective reinforcing filler to prevent deformation. Compared to monolithic aluminum(in tension), Al–0.3 wt% GNPs composite exhibited higher 0.2% yield strength(+14.7%), ultimate tensile strength(+11.1%) and lower failure strain( -40.6%). Surprisingly, compared to monolithic Al(in compression), Al–0.3 wt% GNPs composite exhibited same 0.2% compressive yield strength and lower ultimate compression strength(- 7.8%),and lower failure strain(- 20.2%). The Al–0.3 wt% GNPs composite exhibited higher Vickers hardness compared to monolithic aluminum(+11.8%).Scanning electron microscopy(SEM), Energy-Dispersive X-ray Spectroscopy(EDS) and X-ray diffraction(XRD) were used to investigate the surface morphology, elemental percentage composition, and phase analysis, respectively.     

朝鲜崖柏生境及高生长规律分析

采用标准地调查法测定朝鲜崖柏的土壤特征、林下植被和高生长规律.结果表明:朝鲜崖柏生长于土层较薄且呈弱酸性的山地暗棕壤,不同标准地林下植被差异明显;不同标准地朝鲜崖柏树高的年生长量均呈逐年下降趋势.     

Preparation and Mechanical Properties of a Novel Textile Pad for Wound Debridement

Various types of wound debridement approaches are currently available in clinical practice such as autolytie, enzymatic. biodebridement, mechanical, and surgical debridemenl techniques. A critical look at these various options can explain their potential but also their limitations. In this study, a novel textile pad, which is composed of polyester filaments on the fleecy side and a bioeompatible coating on the opposite side, was made to provide a safe, inexpensive, easier and especially more efficient debridement process that can be used in all healthcare settings by all healthcare practitioners. Eighteen kinds of samples were prepared with different pile density, ground yarn count and coating amount. Dimensional morphology, stitch density, mass per unit area and mechanical properties were investigated to study the intrinsic relationship of structure and properties of textile pad for wound debridement. Results showed that tensile strength and suturing strength at piped site increased obviously with the increment of ground yarn count, while the amount of coating could also have a slight impact on these two properties. However, compressive load was mainly affected by pile density, with no obvious relation to ground yarn count and coating amount.     

A novel process for comprehensive utilization of vanadium slag

Traditional processes for treating vanadium slag generate a huge volume of solid residue and a large amount of harmful gas, which cause serious environmental problems. In this study, a new process for the comprehensive utilization of vanadium slag was proposed, wherein zeolite A and a V₂O₅/TiO₂ system were synthesized. The structural properties of the as-synthesized zeolite A and the V₂O₅/TiO₂ system were characterized using various experimental techniques, including X-ray diffraction, X-ray fluorescence, scanning electron microscopy, and infrared spectroscopy. The results reveal that zeolite A and the V₂O₅/TiO₂ system are successfully obtained with high purity. The results of gas adsorption measurements indicate that the prepared zeolite A exhibits high selectivity for CO₂ over N₂ and is a candidate material for CO₂ capture from flue-gas streams.