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991.
《Tetrahedron letters》2004,45(27):5203-5205
The first synthesis of polyfunctionalized 4-ferrocenyl-4H-pyran and 4-ferrocenyl-1,4-dihydropyridine derivatives, as well as some of their relevant properties, including an electrochemical study and some aspects of their biological profile have been described. 相似文献
992.
制备了负载铬酸氢根的季铵树脂,研究了以该树脂为氧化剂将糠醇氧化为糠醛的反应,考察了温度,时间、溶剂,树脂与醇的摩尔比对该氧化反应的影响。在优化反应条件下,即以苯为溶剂,n(树脂):n(醇)=3.5:1,反应回流10h,糠醛产率达75%,实验中铬酸氢根季铵树脂选择性地将糠醇氧化为糠醛,表明它是一种有效的、可套用的氧化剂。 相似文献
993.
Masafumi Kobayashi Tetsuya Inoguchi Takashi Iida Takashi Tanioka Hiroshi Kumase Yasushi Fukai 《Journal of fluorine chemistry》2003,120(2):2838-110
Direct fluorination of 1,3-dioxolan-2-one with elemental fluorine was successfully carried out to provide 4-fluoro-1,3-dioxolan-2-one, which was expected as an additive for lithium ion secondary battery. 4-Fluoro-1,3-dioxolan-2-one was also further fluorinated with elemental fluorine to give three isomers of difluoro derivatives by the same methodology. Another topic is the preparation of trifluoromethanesulfonyl fluoride, an intermediate of lithium battery electrolyte, by the reaction of methanesulfonyl fluoride with elemental fluorine. The use of perfluoro-2-methylpentane as a solvent gave satisfactory selectivity of trifluoromethanesulfonyl fluoride. 相似文献
994.
Moriya K. Yamada T. Sakai K. Yano S. Baluja S. Matsuo T. Pritz I. Vysochanskii Y. M. 《Journal of Thermal Analysis and Calorimetry》2002,70(2):321-328
Heat capacities of the Pb2xSn2(1-x)P2Se6 crystals (x=0, 0.098, 0.251, 0.402 and 1.0) were measured using an adiabatic calorimeter at temperatures between 10 and 350 K. In the
crystal of x=0, two heat capacity anomalies corresponding to the ferroelectric commensurate - intermediate incommensurate(C-IC) phase
transition temperature T
i, and the incommensurate - paraelectric (IC-N) phase transition temperature T
c, were observed at 193.24±0.10 and 220.07±0.15 K, respectively. The phase transition temperatures decreased with an increase
in Pb2+ concentration. The anomaly at Ti disappeared at x=0.251 in the mixed systems of the Pb2xSn2(1-x)P2Se6. In the crystal of Pb2P2Se6 (x=1.0), no phase transition was observed. The normal heat capacities for the mixed crystals were determined by least squares
fitting of the Debye and Einstein functions to the experimental data. The anomalous heat capacities gave the phase transition
entropies of 8.5 and 1.5 J mol-1 K-1 for x=0. The large transition entropies are consistent with an order-disorder mechanism in the ferroelectric-paraelectric phase
transitions in x=0.
This revised version was published online in August 2006 with corrections to the Cover Date. 相似文献
995.
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。 相似文献
996.
1,2,4-三嗪类化合物具有抗癌、抗病毒、杀虫、抑制中枢神经系统等多种作用。前文用苯甲酰基硫代甲酰胺直接与氨基脲反应,制备了8种新的4,6-二取代-3-酮-5-硫酮-1,2,4-三嗪类化合物(a—h),本文测定了其电子轰击质谱、高分辨质谱及联动扫描质谱,以了解其质谱裂解途径。 相似文献
997.
A new quantum scattering approach (linear combination of arrangement channels-scattering wavefunction, LCAC-SW) proposed by Deng and his co-workers is used to calculate collinear state-to-state reaction probabilities for the F + H2(v) → HF(v') + H system. Several interesting problems such M threshold energy, compound states and enhance by translational energy of the reactants and the vibration excitation of products are discussed and they are compared with other theoretical investigations reported in the literature. It is shown that the LCAC-SW approach is the successful one of quantum scattering methods. 相似文献
998.
N. Bélaïd-Drira H. Zamali M. Jemal 《Journal of Thermal Analysis and Calorimetry》1996,46(5):1449-1458
Phase diagram of the binary system LiNO3-NaNO3 has been obtained by using direct and differential thermal analysis between 323 and 623 K. This system is characterized by an eutectic plateau at 467 K. The eutectic point is at 0.465 mole NaNO3. A peritectic appears at 550 K. There is no miscibility in the solid state. These findings associated with some other thermodynamic results have been used to calculate the activities of the constituents along the liquids curve and the excess thermodynamic functions at 618 K. The constituents seem not to have a symmetrical influence on the thermodynamic quantities. 相似文献
999.
Jun-ichi Azuma Nam-Hun Kim Laurent Heux Roger Vuong Henri Chanzy 《Cellulose (London, England)》2000,7(1):3-19
The cellulose system of the viscous fibrous cellulosic polysaccharide (viscan) in the viscin tissue of the European mistletoe, Viscum album L., was analyzed by chemical and physicochemical techniques including sugar analysis, optical and transmission electron microscopy, X-ray and electron diffraction together with solid state CP/MAS 13C-NMR spectroscopy. The results confirmed that in the elongated thin viscin cells, the cellulose microfibrils (having a diameter of around 3 nm) were tightly coiled with their axes perpendicular to the long axis of the cell. Upon stretching these cells became deformed by more than a hundred fold. In such a deformation, the cellulose microfibrils became unwound to be perfectly aligned along the stretching direction. Based on solid-state CP/MAS 13C-NMR spectroscopic analysis of the viscin tissue, it was found that its cellulose consisted of I and I polymorphs in the ratio 1:1. 相似文献
1000.
Yannis Dotsikas 《Analytica chimica acta》2004,509(1):103-109
This study describes the employment of a novel imidazole-substituted phenol [4-(1-imidazolyl)phenol] as a highly potent signal enhancer in a horseradish peroxidase (HRP)-luminol chemiluminescence (CL) immunoassay. This competitive-type immunoassay for the model antigen fentanyl is based on the use of fentanyl polyclonal antibody immobilized on white microtiter plates and a biotinylated bovine serum albumin (BSA)-fentanyl derivative as a tracer. The latter was detected by means of streptavidin labeled with HRP, resulting in the generation of a high-intensity and relatively stable chemiluminescent signal, immediately after the addition of the substrate solution (NOAS). The developed method fulfilled the requirements of accuracy (percentage recovery ranged from 93.8 to 107%) and precision (intra- and inter-assay CVs were 2.5-5.2 and 4.5-11.9%, respectively). Its plasma detection limit (1.05 pg ml−1) was lower than those of previous immunoassays. The novel assay was compared in terms of sensitivity and concentration range with other common HRP substrate systems: luminol-p-iodophenol-H2O2 and TMB-H2O2. Finally, the described method was compared with an HRP-fentanyl conjugate-based assay, similar to commercially available kits (SKIT), employing the novel substrate solution for both assays and the differences observed were explained by applying previously described models. The detection limit was 4.82 pg ml−1 for SKIT, recovery values were 94.2-105% and intra- and inter-assay CVs were 2.5-5.2 and 4.5-11.9%, respectively. In conclusion, the proposed assay could be utilized for a wide range of molecules and replace the existing enzyme-labeled antigen-based kits. 相似文献