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981.
LiMingWEI QingYuOU JuBaiLI 《中国化学快报》2004,15(9):1127-1130
The sol-gel technology is applied for the preparation of solid-phase microextraction (SPME) fiber. The fiber demonstrates high thermal stability, efficient extraction rate and the selectivity for non-polar or low-polar analytes. Efficient SPME-GC-FID analyses of benzenetoluene-ethylbenzene-xylenes (BTEXs) and low-polar halocarbon were achieved by the sol-gel coated DSDA-DDBT-TiO2 fiber. Some parameters of the SPME fiber for the determination of halocarbon in aqueous sample were investigated. 相似文献
982.
983.
非平面分子内共轭电荷转移化合物的发光行为 总被引:1,自引:0,他引:1
合成了两种分子内共轭的电荷转移化合物:2,3二氰基-5,7-二[2-[(4-二甲氨基)-苯基]乙烯基]-6H-1,4-二氮杂卓(1)及2,3-二氰基-5-苯基-7-[2-[(4-二甲氨基)-苯基]乙烯基]-6H-1,4-二氮杂卓(2). 用UV-Vis吸收光谱和荧光光谱法对它们在不同极性溶剂中的光致变色行为进行了研究.结果表明,化合物的荧光最大发射波长与溶剂的极化参数ET(30)值可在一定范围内构成线性关系,而单臂共轭的化合物2比双臂共轭的化合物1有着更大的Stoke’s位移和基态/激发态偶极矩差.对得到的结果进行了初步的讨论. 相似文献
984.
The binding constants of beta-cyclodextrin (beta-CD) with antalgic drugs such as naproxen, ketoprofen, ibuprofen, acemetacin, and aspirin are determined by affinity capillary electrophoresis. Based on these interactions, a reliable method for the separation and simultaneous determinations of these compounds in the presence of 5.0 mM beta-CD in phosphate buffer solution is presented by capillary zone electrophoresis with UV detection at 214 nm for naproxen and 200 nm for the others. The linear ranges for naproxen, ketoprofen, ibuprofen, acemetacin, aspirin, and caffeine detections are from 2.0 to 800, 2.5 to 1000, 2.5 to 700, 2.5 to 700, 2.0 to 800, and 1.5 to 800 microg/mL, respectively. Their detection limits are 1.0, 0.5, 0.5, 1.5, 1.5, and 1.0 microg/mL at a signal to noise ratio of 3, respectively. This method has been successfully applied to the detections of these drugs in the pharmaceutical formulations (tablets or capsules) and urine samples. 相似文献
985.
DeJuWANG YiTANG AnGangDONG YaHongZHANG YaJunWANG 《中国化学快报》2003,14(12):1299-1302
A novel hollow microsphere structure with cancrinite zeolite grown from the shell of fly ash cenosphere has been successfully prepared through in situ transformation in vapor phase; the orientation and morphology of cancrinite can be greatly improved by adding tetrapropylammonium hydrate into the synthetic system. 相似文献
986.
The solid and solution structures of a new optically active aminopyridine compound, 2‐[(1S)‐(+)‐10‐camphorsulfonamino]‐6‐aminopyridine [(S)‐csaap], 1 , are reported. Crystal data: space group P21, a = 8.9729 (5), b = 10.9447 (6), c = 36.693 (2) Å, β = 96.435 (1)°, V = 3580.8 (3) Å3, Z = 8, R1 = 0.0673 and wR2 = 0.1600 with I > 2σ(I). This chiral compound shows an unprecedented cocrystallization of four stereoisomers, which are characterized by X‐ray crystallography and NMR spectroscopy. 相似文献
987.
A multi-step process was used for preparation of three-dimensionally ordered macroporous (3DOM) SiO2, in which fully accessible Ag nanoparticles are incorporated. The method involves the processes of assembly of polystyrene colloidal crystal, preparation of 3DOM SiO2, and incorporation of Ag nanoparticles within 3DOM SiO2 through in situ Tollens‘ reaction. XRD, SEM and EDXS determination show that the Ag particles deposited on the macroporous walls in nano dimension. The results indicate that lower concentration of silver ammoniate and for-maldehyde in the solution is favorable for forming a very narrow size distribution and uniform shape of nanoparticles. However, the higher the concentration of the solution and the more the loading times, the larger the possibility to form un-uniform particles. Ag nanoparticles can be sintered into larger and spheral particles by calcination at 600℃, but can resist sintering owing to their high dispersivity when loading amount is small. The study provided a simple approach to tailor Ag/3DOM SiO2 composite materials with desired morphology and size of Ag particles within the macropores. 相似文献
988.
Eun‐Ju Kim Chong‐Hyeak Kim Sock‐Sung Yun 《Acta Crystallographica. Section C, Structural Chemistry》2007,63(9):m427-m429
The title complex, [Li2(C6H3N2O5)2(H2O)4], contains two kinds of Li atoms, viz. five‐coordinated and four‐coordinated. The five‐coordinated Li ion has a tetragonal–pyramidal geometry, with a water molecule in the apical position and four O atoms from two 2,4‐dinitrophenolate (2,4‐DNP) ligands in the basal plane. The four‐coordinated Li ion has a tetrahedral geometry, with three water molecules and one phenolate O atom of a 2,4‐DNP ligand. The Li ions are bridged by a phenolate O atom, giving the complex a dinuclear structure. The crystal packing is stabilized by O—H...O hydrogen‐bonding interactions involving the water molecules and nitro O atoms. 相似文献
989.
Shen Chaohong Bao Borong Bao Yizhi Wang Gaodong Qian Ju Cao Zhengbei 《Journal of Radioanalytical and Nuclear Chemistry》1994,178(1):91-98
The extracting abilities for thorium, uranium and some fission products by five sulfoxides are given. The results show that di(2-ethylhexyl) sulfoxide (DEHSO) is not only completely miscible with kerosene, but also superior to tri-n-butyl phosphate in some properties. The extraction behavior of uranium, thorium and some fission products such as zirconium, niobium and ruthenium from aqueous nitric acid with DEHSO in kerosene has been studied over a wide range of conditions. DEHSO extracted uranium and fission products better than TBP under all conditions and is similar to TBP in extraction of thorium. A study of extraction mechanism indicates that U and Th are extracted as disolvates, whereas HNO3 is extracted as monosolvate. Extraction of the two actinides decreases with increasing temperature, indicating the extraction to be exothermic. Preliminary studies show that -ray irradiated DEHSO extracts Zr and Nb to a smaller extent than irradiated TBP in the range of 104–107 rad. 相似文献
990.
A. Ya. Strakov M. V. Petrova Ju. Popelis A. A. Krasnova N. A. Strakova 《Chemistry of Heterocyclic Compounds》1996,32(2):221-226
The reaction of 2 formyldimedone with 2-amino- and 2-hydrazinobenzimidazoles at 20°C in ethanol gave 2-(2-benzimidazolyl)aminomethylene- and 2-[2-(2-benzimidazolyl)hydrazinomethylene]-5,5-dimethylcylohex-anediones, while this reaction carried out in ethanol at reflux in the presence of acid gave 2,2-dimethyl-4-oxo 1, 2, 3, 4-tetrahydroquinazolino(1, 2-a]benzimidazole and 1-(2-benzimidazolyl)-6, 6-dimethyl-4-oxo-4, S, 6, 7-tetrahydroindazole, respectively.Translated from Khimiya Geterotsiklicheskikh Soedinenii, No. 2, pp. 247–252, February, 1996. 相似文献