大孔-介孔氮掺杂二氧化钛的制备及其光催化性能测试

以嵌段共聚物为模板剂,甲酰胺为氮源,结合溶胶凝胶法制备了具有可见光活性的大孔-介孔氮掺杂二氧化钛(N-TiO2)材料.通过X射线衍射、低温N2吸附-脱附、扫描电镜、紫外-可见吸收光谱等手段,考察了嵌段共聚物对样品微结构和可见光活性的影响.结果表明,样品主要以锐钛矿相和板钛矿相混合形式存在;改变嵌段共聚物的浓度,可以制得晶粒粒径9～12 nm,孔径10～14 nm,禁带宽度2.98～2.76 eV的大孔-介孔N-TiO2,且随着模板剂加入量的增加,大孔孔径增大,孔壁增厚.对甲基橙溶液的室内自然光降解实验表明,大孔-介孔N-TiO2具有良好的光催化活性,随着嵌段共聚物加入量的增加,样品对甲基橙的降解时间缩短,降解率提高.     

介孔二氧化钛的制备及铜（Ⅱ）对其光催化氧化活性的影响

采用十六烷基三甲基溴化铵为模板剂,钛酸正四丁酯为原料,水热法合成出孔径为4.4 nm介孔二氧化钛.通过X射线粉末衍射仪、透射电子显微镜和氮气吸附技术对样品进行了表征.以甲基橙为模型化合物,考察了铜(Ⅱ)对介孔二氧化钛光催化活性的影响,研究表明:介孔二氧化钛的光催化活性与P25纳米二氧化钛相当,铜(Ⅱ)的加入提高了介孔二氧化钛的光催化活性,甲基橙的光催化降解速率与光强度成正比.     

铬和硫共掺杂二氧化钛催化剂的制备及其可见光催化性能

以钛酸四丁酯为前驱体,硝酸铬和硫脲为掺杂离子给体,通过溶胶-凝胶法成功制备了纯TiO2、不同浓度的铬掺杂和铬/硫共掺杂TiO2光催化剂.以靛红为目标污染物,进行了可见光催化降解活性测试实验.结果表明,共掺杂催化剂的活性高于未掺杂和单掺杂催化剂.当共掺杂催化剂含0.60%(原子比)的铬,1.2%(原子比)的硫,焙烧温度为500℃时具有最高的光催化降解活性.X射线衍射、N2吸附、X射线光电子能谱和紫外-可见漫反射吸收光谱表征结果显示,共掺杂催化剂为锐钛矿型,具有较高的比表面积,对可见光有较强的吸收能力.共掺杂TiO2具备较高可见光催化活性的原因可能是铬掺杂降低了TiO2的禁带宽度,拓展了可见光吸收区域,而硫掺杂能够维持体系的电荷平衡,增强催化剂对可见光的吸收.     

RE-B共掺杂片层TiO2的合成及其光催化性能

采用溶胶-凝胶法,利用钛酸四丁酯、硝酸镧、硝酸铈和硼酸为原料,对TiO₂光催化剂进行稀土-B(RE-B)的共掺杂改性制备和性能研究。采用X-射线衍射法(XRD)、冷场发射扫描电子显微镜(SEM)、X射线光电子能谱(XPS)、紫外-可见吸收(UV-Vis)光谱和荧光(PL)光谱对制得样品的相组成、表面形貌结构、表面元素组成、光响应范围及带隙能和电子-空穴的复合情况进行了初步分析。结果表明,所制掺杂TiO₂的组成均为锐钛矿型,掺杂使晶格发生了较大畸变,且细晶粒由未掺杂的27 nm减小到RE-B-TiO₂的10 nm,形貌为片层状不规则堆放状态存在。XPS结果表明掺杂元素有效进入二氧化钛, PL谱显示共掺杂可有效延长光催化剂的载流子寿命。掺杂后吸收边均红移, La-B-TiO₂由TiO₂的405 nm移动到466 nm,相应地禁带宽度减小了0.4 eV。光催化实验表明:2 h内降解亚甲基蓝(MB)时掺杂能够同时提高紫外和可见光下二氧化钛的光催化效率,而共掺杂的降解效果又优于单掺杂, La-B-TiO₂紫外光下的降解率达到80.67%,为同等条件下纯TiO₂的2.7倍,可见光下的降解率为74.78%。     

N掺杂TiO2纳米晶：水热-热分解法制备及光催化活性

以钛酸四丁酯和氨水为原料，通过水热法制得层状钛酸铵前驱体，并在400 ℃下对其进行热分解，制得了N掺杂的锐钛矿TiO₂纳米晶。紫外-可见漫反射谱图显示，N掺杂后产物的吸收边红移至550 nm左右，禁带宽度减小至2.25 eV。结合X射线衍射、X射线光电子能谱、红外光谱及热重分析等表征手段，分析了前驱体的制备和热分解条件、产物的晶型转化和表面结合态及其与光催化活性的关系，探讨了层状钛酸铵的形成条件和N掺杂作用机理。本工作条件下，以氙灯为光源，水中活性艳红X-3B为探针的光催化结果表明，辐射40 min X-3B的降解率为99.4%；加装紫外滤光片后，辐射120 min降解率为97.8%。     

氮掺杂二氧化钛粉体的制备及掺杂机理研究

以钛酸四丁酯为钛源,尿素为氮源制备了N掺杂二氧化钛粉体。采用X射线衍射、透射电镜和紫外-可见吸收光谱对粉体晶粒尺寸、物相及光吸收性质进行了表征。结果表明,N掺杂有效抑制了二氧化钛晶粒的长大,并使TiO2光吸收效果大大提高。采用密度泛函方法对掺杂机理进行研究证明,N掺杂有效减小了TiO2带隙宽度,使吸收谱红移,相比替位氮掺杂,间隙氮掺杂更有利于提高光吸收效率。     

负载金的掺氮二氧化钛的制备及其可见光催化性能

以纳米管钛酸为前驱体,采用水热法先制备得到新型N掺杂二氧化钛,然后用沉积沉淀法在N掺杂二氧化钛表面负载微量贵金属Au,制备得到负载Au的掺N二氧化钛.利用TEM、XRD、XPS、ESR和DRS等手段研究了样品的形貌、晶体结构、元素化学态和光谱吸收性质.样品光催化活性通过可见光催化降解丙烯进行评价,结果表明,样品N-TiO₂和Au/N-TiO₂具有明显的可见光(λ≥420 nm)催化活性.ESR结果表明,掺氮过程中生成的束缚单电子的氧空位是样品具有可见光响应的原因.     

一步火焰辅助热解法制备Fe掺杂嵌碳TiO2及其光催化性能

以钛酸四丁酯、无水乙醇和无水氯化铁为前驱体,通过一步火焰辅助热解法制备了Fe掺杂嵌碳TiO₂,并研究了样品的光催化活性. 利用扫描电子显微镜及能谱、X射线光电子能谱、X射线粉末衍射和紫外-可见漫反射吸收光谱等对样品的形貌、组分、晶型和光吸收进行了表征,并研究了样品在紫外和可见光下的光催化活性. 结果表明,无需后续热处理可直接得到主要是锐钛矿相TiO₂的样品,Fe³⁺以替位掺杂形式进入TiO₂晶格,随掺杂量增加,样品在可见光区域的吸光度提高,吸收带边红移. Fe掺杂量（摩尔分数）小于0.2%可改善样品的光催化活性,当Fe掺杂量为0.1%时,样品在可见光和紫外-可见光照射下均显示出最高的降解亚甲基蓝速率.     

氮掺杂二氧化钛粉体的制备及掺杂机理研究

以钛酸四丁酯为钛源,尿素为氮源制备了N掺杂二氧化钛粉体。采用X射线衍射、透射电镜和紫外-可见吸收光谱对粉体晶粒尺寸、物相及光吸收性质进行了表征。结果表明,N掺杂有效抑制了二氧化钛晶粒的长大,并使TiO₂光吸收效果大大提高。采用密度泛函方法对掺杂机理进行研究证明,N掺杂有效减小了TiO₂带隙宽度,使吸收谱红移,相比替位氮掺杂,间隙氮掺杂更有利于提高光吸收效率。     

锌离子掺杂的二氧化钛介孔空心微球的制备及光催化性能

以二氧化硅为模板,钛酸四丁酯（TBOT）为钛源,硝酸锌为锌源,采用溶胶凝胶法制备了锌离子掺杂的介孔二氧化钛空心微球。采用X射线衍射（XRD）、比表面积（BET）、透射电镜（TEM）、扫描电镜（SEM）和X射线光电子能谱（XPS）等技术对样品进行表征,以亚甲基蓝（MB）的光催化降解为目标反应评价其光催化活性。结果表明,去核之后的复合微球为空心微球,壁厚为20nm左右。钛酸四丁酯溶液的滴加时间对微球的形貌影响较大,当滴加时间大于15min时,可以得到结构清晰的空心微球。用氢氧化钠溶液去除二氧化硅核,反应90min,二氧化硅可以被完全去除。X射线衍射表明,实验得到的掺杂锌离子的空心微球和没有掺杂锌离子的空心微球都是锐钛矿。当锌离子的摩尔分数为0.3%时,二氧化钛空心微球的晶粒尺寸最小,比表面积最大,催化亚甲基蓝降解的效率最高。     

Dichroism of absorption and polarization of phosphorescence of molecules of the closed form of nitrobenzospirothiopyran

The spectral-polarization characteristics of absorption and phosphorescence of molecules of the initial form of nitro-substituted indolinospirobenzothiopyran were studied in oriented polyethylene films and in solutions with different polarity. An oscillator model of the electron transitions responsible for the formation of absorption and luminescence spectra was suggested. It was established that the principal differences in the spectral and photophysical properties of the compound studied and its oxygen-containing analog are associated with the fact that the electronegativity of the S atom is lower than that of the O atom. Translated fromIzvestiya Akademii Nauk. Seriya Khimicheskaya, No. 6, pp. 1143–1146, June, 1997.     

非那雄胺合成工艺改进

非那雄胺能抑制5α-还原酶的活性,明显降低二氢睾酮水平,是一种治疗良性前列腺增生的有效药品。该合成工艺以甾烯酮酸为原料,将其与氯化亚砜反应,无须分离即与叔丁胺反应得17β-酰胺化合物,再氧化开环,环合,氢化,脱氢合成了非那雄胺。经元素分析、IR、1HNMR、13CNMR、MS分析表征了其结构。该法无须使用昂贵的2,2-二吡啶二硫化物和剧毒药品苯亚硒酸酐,且以乙酸铵代替氨气,降低了对设备的要求和腐蚀,更适用于工业生产。     

Acid hydrolysis of carboxymethylcellulose of low degree of substitution

Cotton cellulose was swollen in a sodium hydroxide solution and carboxymethylated by a two-bath method for different periods of time for each process. The kinetics of acid hydrolysis and the crystallinity of the swollen and carboxymethylated samples were measured. The proportion of broken bonds, rate constants for hydrolysis, and permeability of cellulose to hydrolyzing agents were calculated. The susceptibility of glycosidic linkages to acid hydrolysis was improved by carboxymethylation more than by swelling in alkali. The increased accessibility of carboxymethylcellulose to acid was regarded as a consequence of increased intra-and intercrystalline swelling and of the glycosidic bonds' weakness caused by the electron-attracting carboxymethyl group on the C-6 position.     

恶臭嗅辨实验室建设探讨

针对恶臭测试的环境影响问题,提出了解决的实例方案,并对方案的要点及优缺点进行讨论,此方案在实际操作中具有较好的效果。     

Estimation of Kinetic Parameters of Thermal Oxidation of Ilmenite

The aim of the presented work was the investigation of thermal oxidation of ilmenite in static air atmosphere. The investigations were carried out by use of a derivatograph (MOM, Hungary). The changes of crystallographic structure of investigated samples were identified by X-ray diffractometry on Philips PW-1710 diffractometer. In temperature above 500°C appears structure of hematite Fe₂O₃. On the basis of the thermogravimetric measurements, the contracting area and contracting volume models were found as the best fitting experimental data. This revised version was published online in August 2006 with corrections to the Cover Date.     

Mechanism of action of base-catalyzed oxygenation of phenol derivatives

Cyclopropyl derivative of 2,6-di-tert-butylphenol is synthesized as a probe to investigate the mechanism of base-catalyzed autooxidation of phenol derivatives. Our study indicates that one electron reduction of molecular oxygen from phenolate gives phenoxyl radical 3, a key intermediate of autooxidation. The coupling of phenoxyl radical and superoxide radical gives peroxylate anion 4 and produces the final epoxy alcohol adduct 6.     

氯氧化镁生成热的研究

用氧化镁氯化镁水溶液制备了8水合氯氧化镁[nMg(OH)2·MgCl2·8H2O], 并测定了其在盐酸中的溶解热, 实验结果表明, 氯氧化镁溶解热与n值呈线性关系, 根据溶解热求出5Mg(OH)2·MgCl2·8H2O和3Mg(OH)2·MgCl2·8H2O的生成热分别为-7727.1和5888.1kJ·mol^1^-。     

Determination of heats of detonation and influence of components of composite explosives on heats of detonation of high explosives

The heats of detonation of 20 simple high explosives and explosive mixtures were determined by means of an adiabatic detonation calorimeter designed by the authors. The results indicated that the performance of the instrument was reliable and the experimental data were very accurate. For explosive mixtures, there was a linear accumulative relationship between the heats of detonation of the explosive mixture and its components. Accordingly, the heats of detonation of explosive mixtures could be calculated directly from the heats of detonation of simple explosives and the characteristic heats of other components. The experiments showed that the gold or brass shell of the cylindrical charge could be substituted by a thick-walled porcelain shell, which had the advantage of cheapness.

     

化学计量中不确定度评定研究进展

测量不确定度是表征合理地赋予被测量之值的分散性的参数。本文针对化学计量不确定度评定基础模型仅适用于线性模型、概率分布为正态分布或缩放位移t分布等局限,介绍了近年来不确定度评定的研究热点:蒙特卡罗方法(Monte Carlo Method,MCM),不确定度评定的来源、评定概念、评估方法及其发展过程,扩大了测量不确定度评定与表示的适用范围。     

微量钙的测定方法研究进展

介绍了1995-2006年期间测定微量和痕量钙的方法,如电感耦合等离子体-原子发射光谱法、原子吸收光谱法以及离子色谱法等的工作原理和特点,并说明了其测定微量钙的应用领域。并对微量钙的测定技术进行了展望(引用文献55篇)。