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181.
ChuanChunZOU ShuJieHOU PingShengLEI XiaoTianLIANG 《中国化学快报》2003,14(4):361-364
Two spirostanol saponins(gracillin and dioscin)which have the typical sugar moieties were synthesized facilely by a general approach. 相似文献
182.
Yao‐Cheng Shi Bei‐Bei Zhu Xiao‐Bi Jing 《Acta Crystallographica. Section C, Structural Chemistry》2006,62(11):m559-m562
The molecules of N,N′‐bis(2‐pyridylmethyl)ferrocene‐1,1′‐diyldicarboxamide, [Fe(C12H11N2O)2], contain intramolecular N—H⋯N hydrogen bonds and are linked into sheets by three independent C—H⋯O hydrogen bonds. The molecules of the isomeric compound N,N′‐bis(3‐pyridylmethyl)ferrocene‐1,1′‐diyldicarboxamide lie across inversion centres, and the molecules are linked into sheets by a combination of N—H⋯N hydrogen bonds and π–π stacking interactions between pyridyl groups. 相似文献
183.
Yan Xiao Jian Wang Wang Xia Guang Feng Huai You Wang 《Journal of Analytical Chemistry》2007,62(5):438-443
The maximum emission wavelength of dopamine is 317 nm with excitation at 290 nm. The relative fluorescence intensity of dopamine
decreased in the presence of enoxacin, which showed that fluorescence quenching occurred. The Stern-Volmer (S-V) plot showed
a nonlinear relationship between the relative fluorescence intensity of dopamine and the concentration of enoxain. The quenching
mechanism was studied and the results suggested that both dynamic and static quenching processes were responsible for the
observed positive deviation in the S-V plot. When the S-V plot was modified by logarithm, the linear relationship was obtained
between logF
0/F and C in the range of 0.10 to 13.0 μg/mL (where F
0 is the relative fluorescence intensity of dopamine, F is the relative fluorescence intensity of dopamine in the presence of enoxacin, and C is the concentration of enoxacin). The fluorescence quenching method for the determination of enoxacin was developed. The
linear regression equation of the calibration graph of enoxacin was C = 13.70 (logF
0/F) − 0.5836, with the correlation coefficient 0.9984. The detection limit was 2.0 ng/mL and the relative standard deviation
was 2.52%. The effects of pH, the stability of dopamine in the presence of enoxacin, and foreign ions on the determination
of enoxacin have been examined. The recovery of enoxacin was from 94.9 to 103.0% in a human serum sample and from 94.9 to
108.0% in a urine sample. The method is simple, rapid, and can be used for the determination of enoxacin in human serum and
urine samples with satisfactory results.
The text was submitted by the authors in English. 相似文献
184.
185.
A New Synthetic Route to 12-Oxo-1, 15-pentadecanlactam 总被引:1,自引:0,他引:1
JiaXingHUANG XiaoMeiLIANG DaoQuanWANG 《中国化学快报》2004,15(2):169-170
12-Oxo-1,15-pentadecanlactam 7 was synthesized from cyclododecanone with a totalyield of 36% in a seven-step reaction. The azide 5 to 12-nitro-1,15-pentadecanlactam 6 is the key step featured by direct ring expansion. 相似文献
186.
Preparation and Characterization of Microencapsulated Hexadecane Used for Thermal Energy Storage 总被引:3,自引:0,他引:3
GuangLongZOU ZhiChengTAN XiaoZhengLAN LiXianSUN TaoZHANG 《中国化学快报》2004,15(6):729-732
Polyurea microcapsules about 2.5μm in diameter containing phase change material for thermal energy storage application were synthesized and characterized by interfacial polycondensation method with toluene-2,4-diisocyanate and ethylenediamine as monomers in an emulsion system. Hexadecane was used as a phase change material and OP, which is nonionic surfactant, and used as an emulsifier. The chemical structure and thermal behavior of the microcapsules were investigated by FTIR and thermal analysis respectively. The results show encapsulated hexadecane has a good potential as a solar energy storage material. 相似文献
187.
The geometric and electronic structures of FeS(2) (100) surface have been studied by a quantum-mechanical calculation using a total-energy pseudopotential code, CASTEP. The (100) surface is very stable and does not give any significant geometric relaxation. The electronic structure of FeS(2) (100) surface is characterized by the appearance of new native surface states in the bulk band gap, which correspond to antibonding mixed Fea-Ssp(3) states. These surface states play an important role as mediators of electron transfer on both anodic and cathodic sites in the incipient oxidation of pyrite. Moreover, the (100) surface has small band gaps and shows some metallic character. It is predicted that the rate of cathodic reductive reaction of O(2) in the incipient oxidation of pyrite is much faster than previously considered. The transport of electrons from the anodic sites to the cathodic sites on the (100) surface is faster and hole injection of anodic sites is not the rate-determining step. So we can deduce that the rate-determining step of incipient oxidation for pyrite consists of both electron transfer of pyrite/aqueous O(2) interface and the splitting of H(2)O. 相似文献
188.
HuaRongZHAO XiaoFengLI XinJianZHAO YangPingNIU 《中国化学快报》2004,15(11):1292-1294
Aryl selenoamides react smoothly with a-haloacetic acid in various alcohol to givecorresponding bis(carboxyalkylmethyl) diselenides in good yields. 相似文献
189.
QiongCHENG TuZhiPENG XiaoBoHU CatherineF.YANG 《中国化学快报》2004,15(12):1473-1476
A novel fibroin modified electrode with ion recognition was reported. The membrane with isoelectric point of pH 4.5, was modified on graphite and carbon fiber electrodes. The pH-responsive ion recognition of the modified electrode was investigated by use of some neurocompounds. The fibroin carbon fiber electrode has been used for in-vivo determination. 相似文献
190.
表面电沉积Ni—La2O3复合镀层的Fe26Cr1Mo不锈钢的氧化行为研究 总被引:3,自引:0,他引:3
Fe26Cr1Mo不锈钢在900℃氧化时,生成的氧化层在冷却过程中大量剥落,经表面共电沉积NiLa2O3复合镀层后,抗热循环能力明显提高。 相似文献