Determination of molecular orientation distribution of a stable paramagnetic probe in oriented 4-cyano-4’-<Emphasis Type="Italic">n</Emphasis>-pentylbiphenyl

The molecular orientation distribution function of a stable radical 4-hydroxy-2,2,6,6-tetramethylpiperidine-1-oxyl in magnetic-field oriented 4-cyano-4’-n-pentylbiphenyl was determined from the angular dependence of the ESR spectra. The preferred molecular orientation of radical species in the liquid crystal matrix was determined. The temperature evolution of the orientation distribution function was studied.__________Published in Russian in Izvestiya Akademii Nauk. Seriya Khimicheskaya, No. 1, pp. 190–195, January, 2005.     

模糊正交法用于石墨炉探针原子化测定铋条件的研究

模糊正交法是通过把正交试验结果模糊化,然后用模糊数学的理论和方法来处理实验数据。与常规正交设计相比,能在同样实验工作量的情况下获得更多的信息。本文采用模糊正交法对元素Bi的测定条件进行优化,并将其同常规正交设计方差分析的结果进行了比较,并提出一个综合评价参数,对建立的分析方法进行了综合评价。     

EFFECT OF MOLYBDENUM PROMOTER ON THE Cu-Co BASED CATALYSTS

The synthesis of mixed alcohols (C1-C5) from syngas has been studied at 6. 0 MPa over modified Co/CuLaZr catalysts. The molybdenum addition enhanced greatly the activity and the selectivity to alcohols. The improvement of hydrogenation capacity of the system via a reversible spillover effect of hydrogen could explain this effect, together with a great capacity of CO insertion, illustrated by the effect of C2H4 addition as a probe to syngas. Under our experimental conditions, a mixed alcohol production of 147.1g/kg. cat/h containing a proportion of 33. 1% of higher alcohols (C2 OH) was obtained with a selectivity to ROH of 52. 8%.     

Titanium‐implanted CaTiO3 films and their changes in Hanks' solution

Titanium‐implanted CaTiO₃ film was prepared and then characterized by x‐ray photoelectron spectroscopy (XPS) and Rutherford backscattering spectrometry (RBS) before and after immersion in Hanks' solution for 7 days. An as‐prepared specimen contained a small amount of Ar implanted during sputtering, although the pressure was as low as 10^?4 Torr. Even though Ar convolution increased with an increase in the relative Ti ion dose, most of the convoluted Ar was not from the Ar gas used for Ti ion production but rather was from the Ar gas used for sputtering the CaTiO₃. During Ti implantation, the CaTiO₃ films were ion‐etched by Ti ions. The composition of the CaTiO₃ film was not changed to any great degree by the Ti implantation, however its properties changed considerably. After immersion in Hanks' solution, the thickness of the specimen not implanted with Ti decreased the most whereas the [Ca]/[P] ratio, which was nearly unity before exposure, decreased significantly, becoming 0.23 on the Ti‐implanted specimen prepared at 200 W and 0.13 on the Ti‐implanted specimen prepared at 50 W. It was also observed by XPS that the ratio [Ca]/[P] was ～1.9 for all Ti‐implanted specimens after immersion in Hanks' solution for 7 days. Judging from the binding energies of Ca 2p_3/2 and P 2p electrons and the [Ca]/[P] ratio, it was suggested that a hydroxyapatite‐like substance had formed on the surfaces of the Ti‐implanted specimens after immersion in Hanks' solution. Copyright © 2003 John Wiley & Sons, Ltd.     

Study on oxidation of polymers treated by high LET radiation

The oxidation of medical silicone rubber and segmented polyether urethane which were bombarded with 11.2 MeV Si⁺ or F⁺ at the dose of 5 × 10¹⁴ ions/cm² was studied. In XPS measurements, it was found that the oxygen concentration on the surface of the implanted polymeric membranes had been increasing in three months at least. ESR measurement showed that some free radicals existed in these membranes and their quantities decreased with time. Chemical analysis proved that peroxides were generated in the γ irradiated membranes. The reason for the increasing of oxygen concentration was that free radicals combined with oxygen in the air and produced peroxides on the membrane surface. Moreover, in order to demonstrate the radiation mechanism, low LET (γ rays) radiation of such polymeric membranes was carried out for comparison     

利用荧光探针研究聚甲基丙烯酰胺溶液中的疏水微区

利用荧光探针研究聚甲基丙烯酰胺溶液中的疏水微区沈燕清，江鹏飞，吴世康（中国科学院感光化学研究所，北京，１００１０１）关键词荧光探针，疏水微区，聚甲基丙烯酰胺微多相体系研究近年来受到广泛的注意，它不仅是由于长期来已经发现：不同结构的微多相体系如胶束，乳...     

氟代二苯乙烯氨基酸的合成及性能

以4-碘-L-苯丙氨酸为初始原料,经羧基和氨基的保护得到化合物2;化合物2与4-氟苯乙烯进行Heck反应得化合物3;化合物3脱去保护基得氟代二苯乙烯氨基酸(4,47.4%);其结构经1H NMR,13C NMR,IR和MS(ESI-TOF)确证。光学性质研究结果表明:4的激发、发射波长分别为314 nm和355 nm,斯托克斯位移为41 nm,荧光量子产率为0.22。化合物4在甲醇溶液中存在光致顺反异构现象,反式→顺式结构转变速率常数为0.026 min^-1。     

Boron implantation in Si: Channeling effects studied by SIMS and simulation

The axial channeling behaviour of boron implants in <100>, <110> and <111> silicon wafers is investigated by SIMS. Large differences of channeling characteristics such as channeled projected range (the projected range of channeled ions or channeling peak) and the fraction of channeled to implanted ions are observed among the three major crystal orientations. Within the critical angle, the channeling behaviour is very sensitive to the incidence beam angle with respect to crystal orientations. SIMS measurements are performed at different positions along several critical directions over a whole wafer. Well channeled profiles with an incidence beam angle to crystal orientations of 0 ° are obtained for each ion implantation energy and orientation. The results are used to test various models of ion implantation by simulation. A 3-parameter model for electronic stopping power of boron in silicon was proposed.     

Synthesis of a Photolabeling Probe for the Study of Antiviral Mechanism of Ribavirin

Ribavirin has been used in urgency to treat SARS patients recently. In order to study its antiviral mechanism by photolabeling approach, we have synthesized and characterized 5-azido-1-β-D-ribofuranosyl-1,2,4-triazole-3-carboxiamide 1 as a photolabeling probe of ribavirin. The azidotriazole nucleoside showed rapid and clean photochemical reaction, suggesting that 1 is a promising probe to study the antiviral mechanism ofribarivin by photolabeling.     

2-(苯并噻唑-2-基)-5-(N,N-二乙基氨基)苯酚衍生物的合成及其对H2S的识别

以4-N,N-二乙基氨基水杨醛为原料,制备了2-(苯并噻唑-2-基)-5-(N,N-二乙基氨基)苯酚衍生物(探针L),并对其结构进行了表征。在DMSO/PBS(体积比3∶7,pH=7.4)溶液中,探针L具有高选择性并可荧光"关-开"识别H_2S,在365nm紫外灯照射下,由无荧光变成蓝色荧光。实验表明,探针L识别H_2S的检测限为2.05×10~(-6)mol/L,pH适用范围为6～9,可用于检测实际水样中的H_2S。