Structural,Electronic and Optical Properties of the Monoclinic α-CoV_2O_6

First-principles calculations based on density functional theory are performed to investigate the structural,electronic and optical properties of monoclinic α-Co V2O6.Firstly,the geometry structures obtained by geometry optimization are consistent with the experimental values.Then,the energy band structure is studied using both GGA and GGA+U methods.It is found that the on-site Coulomb repulsion of the Co 3d orbital plays a key role in describing the electronic properties of α-Co V2O6,and is necessary to open the energy band gap.According to the partial density of states(PDOS),significant Co–O and V–O hybridizations are observed in the valence and conduction bands,respectively.Furthermore,the Co–O and V–O bonds are found to have significant covalent characters.Below the absorption threshold ~1.9 e V,no absorption can be detected.However,there exists a strong and wide absorption band in the energy range from 1.9 to 11 e V.Such novel optical properties imply that the α-Co V2O6 may have some potential optical applications.     

Selective Oxidation of Methane into Methanol Under Mild Conditions

Selective oxidation of methane to methanol under mild conditions has been considered as a dream reaction but suffers from poor efficiency due to the strong C-H bond of methane and easy overoxidation of the methanol product. For overcoming these problems, a series of strategies has been developed for improving methanol productivity with oxidants of hydrogen peroxide and even a mixture of oxygen and hydrogen at mild temperatures. Significant achievements in these strategies using effective catalysts, such as supported metal nanoparticles, colloidal metal nanoparticles, and metal@zeolites are briefly concluded. Moreover, the current challenges, future perspectives for preparing active, selective, and stable catalysts, have been discussed. The zeolite fixed metal nanoparticle structure has been found to boost the reaction by benefiting the formation and enrichment of peroxide intermediates, which might guide the development of more efficient catalysts.     

气相色谱-微池电子捕获检测法同时检测饮用水中多种有机污染物

本文建立了气相色谱-微池电子捕获检测法(GC-μECD),同时测定生活饮用水中百菌清、七氯、滴滴涕、六六六、林丹、六氯丁二烯、溴氰菊酯、1,1-二-氯苯、1,2-二氯苯、三氯苯、六氯苯11种有机氯,马拉硫磷、对硫磷、甲基对硫磷、毒死蜱、乐果、敌敌畏6种有机磷,以及硝基苯、2,4,6-三硝基甲苯、1,3-二硝基苯、邻,间,对硝基氯苯、2,4-二硝基氯苯,2,4-二硝基甲苯6种硝基苯类有机物的分析方法.样品经萃取后,采用OV-1701色谱柱(30 m×0.25 mm×0.25μtm)程序升温进行分离,用微池电子捕获检测器(μECD)进行检测,通过保留时间定性,外标法定量.结果表明该方法分离效果好,灵敏度高,选择性强,简便、快速、准确,能够满足同时测定生活饮用水中上述23种有机化合物的需要.     

基于Surfer平台的FLAC3D 复杂三维地质建模研究

复杂三维地质体模型的建立一直是FLAC^3D软件前处理过程中的一个难题。因此,提出以Surfer软件为过渡平台,通过对地表及岩层分界面三维地质信息的提取、转换,并将Surfer输出的数据经由FLAC^3D软件内嵌的Fish语言编制的程序的二次转换,生成FLAC^3D软件可以直接读取的模型数据文件,从而实现了该软件前处理过程中复杂三维地质模型的快速、准确建立。同时结合工程实际,检验了该方法的可行性和仿真效果,结果表明,建模过程简捷、实用,可操作性强,是FLAC^3D软件前处理的一种新方法。     

NiO/MWCNTs复合物的固相合成及其电容性能

本文通过PEG-400辅助室温固相反应制备Ni(OH)2/MWCNTs前驱物,经300℃下热分解得到NiO/MWCNTs复合物。借助X-射线衍射(XRD)和透射电镜(TEM)测试对产物的晶型及形貌进行了表征,采用循环伏安及恒流充放电测试手段对所得复合物的电容性能进行了分析。结果表明,针状NiO较均匀地附着于碳纳米管的表面,当MWCNTs的含量为60%时,NiO/MWCNTs复合物电极的放电比容量得以有效改善,0.2A.g-1下的其放电比容量可达949 F.g-1,远高于纯NiO(422 F.g-1)及MWCNTs(201 F.g-1)的放电比容量,显示了二者的协同效应。     

线型脲醛树脂的半结晶模板化作用

酸性条件下硅溶胶体系中尿素和甲醛聚合反应会产生脲醛树脂-氧化硅杂化沉淀. 沉淀的质量随有机组分比例的增加而增加, 当尿素和甲醛物质的量比≥1.0时生成沉淀的量为恒定最大值. 红外分析表明杂化材料在3348, 1635, 1572和784 cm^－1处产生了可被归结为线型结构(—[NHCONHCH₂]_n—)的特征吸收. XRD分析表明这种线型分子可形成氢键(C＝O…H—N)导向型的半结晶. 微分热重和XRD结果证明结晶物种在290 ℃完全分解. SEM表征显示半结晶杂化沉淀以三维网络结构为特征, 具有层状结晶的各向异性, 其初级粒子即使在室温下干燥也容易开裂. 随着反应时间的延长、酸性的增加或无机组分量的相对增加杂化粒子变得更加致密. 液氮吸附结果证明沉淀焙烧后所得氧化硅材料的结构具有层状孔结构性质, 其比表面积、孔尺寸和孔体积可以达到510 m²/g, 14.3 nm和1.68 cm³/g. 改变反应体系的酸性和反应组分配比等条件可以方便地控制杂化材料的结构.     

姜黄素及其改性产物与皮胶原作用研究

我国使用天然染料历史悠久,但随着近代化学工业的发展,出现了合成染料,合成染料以其丰富多彩的色彩和优良的染色牢度而得以广泛应用,天然染料则受到冷落.     

Crystal Structure and Characterization of a Binuclear Cd(II) Quaternary Coordination Complex [Cd2(phen)2Q2(BP)]n (phen = 1,10-Phenanthroline, BP = Biphenyl-4,4--dicarboxylic acid, Q = 8-Hydroxyquinoline Anion)

The structure of a binuclear cadmium(II) quaternary complex, [Cd2(phen)2- Q2(BP)]n 1 (phen = 1,10-phenanthroline, BP = biphenyl-4,4--dicarboxylic acid, Q = 8-hydroxy- quinoline-anion), has been determined by X-ray crystallography and characterized by elemental analysis, IR spectrum and thermogravimetric analysis.It crystallizes in the monoclinic system, space group P21/n with a = 13.1906(18), b = 10.9623(15), c = 16.947(2) -, β = 111.3430(10)°, V = 2282.5(5) -3, Z = 4, Mr = 556.85, Dc = 1.620 g/cm3, F(000) = 1116, μ = 0.994 mm-1 and S = 1.056.In the structure, 1D chains are connected via biphenyl-4,4--dicarboxylic acid, 8-hydroxy quinoline anion and binuclear cadmium atoms into an infinite 1-D molecular chain architecture.Via aryl ring π-π stacking interactions a supramolecular structure is formed in 1.