活性炭负载纳米TiO2光催化降解性能研究

本文研究活性炭负载纳米TiO2的光催化降解性能和影响甲基橙废水处理的主要因素。结果表明:用溶胶-凝胶法制备的TiO2-活性炭催化剂具有比表面积大、分散性高、光催化降解性能好、可重复利用等优点;采用30W高硼紫外光灯,TiO2-活性炭光催化降解浓度为1500mg/L甲基橙废水的最优工艺条件是:催化剂活化温度为700℃、用量为1.0g/L、废水起始pH值为1、反应温度为45℃、光照时间为50m in。在此条件下,甲基橙和CODC r的去除率分别达99.8%和99.7%。     

纳米晶La_（1－_x）Sr_xFeO_3的合成及气敏特性的研究

用柠檬酸盐法合成出Ｌａ_（１－_ｘ）Ｓｒ_ｘＦｅＯ_３（ｘ＝０．１，０．２，０．３，０．４）原粉，再经固相反应得到纳米晶粉末，用ＴＧ、ＤＴＡ、ＸＲＤ、ＩＲ进行了表征，确证复合氧化物Ｌａ_（１－_ｘ）Ｓｒ_ｘＦｅＯ_３为钙钛矿型结构，粒径在１０～２５ｎｍ之间。实验结果表明，随着固相反应条件不同，产物粒径呈规律性变化．气敏特性研究表明，该纳米晶材料对乙醇有较高的选择性和灵敏度，其选择性顺序为Ｌａ_（０．９）Ｓｒ_（０．１）ＦｅＯ_３＞ＬａＦｅＯ_３＞ＬａＦｅＯ_３（大晶粒）。     

Clinical quality vs analytical performance: what are the right targets and target values?

For optimal performance of laboratory tests, testing processes should be designed to provide clinically useful quality and QC procedures should be selected to assure that the necessary clinical quality is achieved in routine production. One important issue is how to define clinical quality. Today’s practice guidelines, quality regulations, and quality standards provide some targets for analytical quality, but they fail to adequately address clinical quality. Target values for precision and accuracy are not the same as clinical quality, though analytical performance certainly contributes to the clinical quality of test results. How can we proceed in our quest to improve quality when there are inconsistencies and inadequacies in the specifications found in practice guidelines, regulations, and standards? Today target values are often being set for the wrong targets. A better approach is possible if we focus on test interpretation guidelines to define clinical quality, then derive specifications for the accuracy and precision that are appropriate for the method, as well the QC rules and numbers of control measurements that are necessary to guarantee the desired quality will be achieved in routine operation of the testing process.     

Immanant positivity for Catalan-Stieltjes matrices

We give some sufficient conditions for the nonnegativity of immanants of square submatrices of Catalan-Stieltjes matrices and their corresponding Hankel matrices. To obtain these sufficient conditions, we construct new planar networks with a recursive nature for Catalan-Stieltjes matrices. As applications, we provide a unified way to produce inequalities for many combinatorial polynomials, such as the Eulerian polynomials, Schröder polynomials, and Narayana polynomials.     

Generalized cyclic cohomology associated with deformed commutators

The generalized cyclic cohomology is introduced which is associated with -deformed commutators . Some formulas related to the trace of the product of -deformed commutators are established. The Chern character of odd dimension associated with -deformed commutators is studied.

     

Modification of HPTLC-plates by in situ chemical bonding with non-polar and polar organosilanes

A method has been developed for the preparation of modified silica plates for high performance thin-layer chromatography (HPTLC). Some typical organosilanes were thus allowed to react in situ with the silica of Merck HPTLC-plates. This method was found to be highly reproducible, simple and cheap. Non-polar plates were prepared and compared with commercial plates from Merck, Whatman and Macherey-Nagel. Modification with cyanodecyltrichlorosilane resulted in plates that showed good coverage, efficiency and low residual silica activity. Silica modified with a multifunctional silane has different properties in different organic solvents. It will appear to be non-polar in a polar solvent and vice versa. New advantageous separation systems are thus made feasible by the presence of cyano groups on the plate. The utility of modified thin-layer plates is demonstrated by the separation of some homologues of p-hydroxybenzoic acid esters and of some polycyclic aromatic hydrocarbons.     

Full Non-rigid Group of Sponge and Pina

The non-rigid molecule group theory (NRG) in which the dynamical symmetry operations are defined as physical operations is a new field in chemistry. Smeyers and Villa computed the r-NRG of the triple equivalent methyl rotation in pyramidal trimethylamine with inversion and proved that the r-NRG of this molecule is a group of order 648, containing a subgroup of order 324 without inversions (see J. Math. Chem. 28(4) (2000) 377–388). In this work, a computational method is described, by means of which it is possible to calculate the symmetry group of molecules. We study the full non-rigid group (f-NRG) of Sponge and Pina molecules with C ₂ and C _i point groups, respectively. It proved that these are groups of order 162 and 13122 with 54 and 3240 conjugacy classes, respectively. The character tables of these groups are also computed.     

聚乳酸及其共聚物载药微球的研究进展

聚乳酸及其共聚物由于其无毒、生物相容性好和可降解性而在医药领域有广泛的应用.本文对聚乳酸及其共聚物在药物控释及靶向方面的研究进行综述和展望.     

Electron transfer from dibenzo[b,f]-1-azapentalene dianion: Attempted synthesis of dibenzo[b,f]-1-azapentalene

When dibenzo[b,f]-1-azapentalene dianion (3) was allowed to react with either iron (III) chloride or ethylene bromide, a one-electron transfer from3 took place readily to give the radical anion11. Further electron transfer from11 did not occur presumably due to the antiaromatic character of dibenzo[b,f]-1-azapentalene (1) that would have resulted. The radical anion11 underwent further transformation by hydrogen abstraction from the solvent to give 5,10-dihydroindeno[1,2-b]indole (2) and by dimerization to themeso and (R,S) isomers of 5,5,10,10-tetrahydro-10,10-biindeno[1,2-b]indole (4 a and4 b) respectively.

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Elektronentransfer von Dibenzo[b,f]-1-azapentalen-Dianion: Ein Versuch zur Synthese von Dibenzo[b,f]-1-azapentalen

Zusammenfassung Die Reaktion von Dibenzo[b,f]-1-azapentalen-Dianion (3) mit Eisen (III) oder Ethylenbromid ergab einen Ein-Elektronentransfer zum Radikalanion11. Ein weiterer Elektronentransfer fand nicht statt, vermutlich wegen des antiaromatischen Charakters von Dibenzo[b,f]-1-azapentalen (1), das dabei entstehen müßte. Das Radikalanion11 ergab unter Wasserstoffentzug aus dem Lösungsmittel 5,10-Dihydroindeno[1,2-b]indol (2), das weiter zummeso- bzw. (R,S)-5,5,10,10-tetrahydro-10,10-biindeno[1,2-b]indol (4 a bzw.4 b) dimerisierte.