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991.
锂辉石—石灰石烧结中煤粉代替重油作燃料的研究和实践 总被引:1,自引:0,他引:1
目前世界锂工业原料以锂辉石为主。我国锂辉石储量居世界首位,主要分布于新疆、四川、湖南等地,其中又以四川的储量占全国第一。锂的主要基础化合物LiOHH2O系用锂辉石-石灰石烧结法而得,烧结燃料是影响LiOHH2O产品价格的重要因素之一。过去国内外均采用... 相似文献
992.
993.
We report a ruthenium-catalyzed reaction for various 3-benzyl but-1-ynyl ethers with suitable functionalities. Treatment of these substrates with TpRu(PPh3)(CH3CN)2PF6 (8.0 mol %) catalyst in 1,2-dichloroethane (80 degrees C, 12 h) afforded functionalized 1,3-dienes and benzyl aldehyde in good yields. This process is considered to be a tandem dealkoxylation and transfer hydrogenation. Deuterium-labeling experiments reveal that the migration of different hydrogen atoms proceeds regiospecifically. A plausible mechanism is proposed on the basis of the results of isotope experiment. 相似文献
994.
Densities have been measured for the electrolyte (NaCl, NaBr and NaI)‐monosaccharide (D ‐mannose and D‐ribose)‐water solutions at 298.15 K. These data have been used to calculate the apparent molar volumes of the saccharides (VΦ,S) and electrolytes (VΦ,E) in the studied solutions. Infinite dilution apparent molar volumes, VΦ,S0 and VΦ,E0, have been evaluated, together with the standard transfer volumes of the saccharides (ΔtVS0) from water to aqueous electrolyte solutions and those of the electrolytes (ΔtVE0) from water to aqueous saccharide solutions. It was shown that both the ΔtVS0 and ΔtVE0 values are positive and increase with increasing molalities of sodium halides and saccharides, respectively. Overall, the ΔtVS0 and ΔtVE0 values have the order of NaCl > NaBr > NaI except for NaI‐ribose and NaI‐ribose. Volumetric interaction parameters for the electrolyte‐monosaccharide pairs in water were obtained and interpreted by the stereochemistry of the monosaccharide molecules and the structural interaction model. 相似文献
995.
Liu JA Petzold CJ Ramirez-Arizmendi LE Perez J Kenttämaa H 《Journal of the American Chemical Society》2005,127(37):12758-12759
Laser-induced acoustic desorption combined with mass spectrometry has been used to demonstrate that phenyl radicals can attack dinucleoside phosphates at both the sugar and base moieties, that purine bases are more susceptible to the attack than pyrimidine bases, and that the more electrophilic the radical, the more efficient the damage to dinucleoside phosphates. 相似文献
996.
A high-performance liquid chromatographic method for the simultaneous separation and determination of nine podophyllum lignans and two flavonoids in Podophyllum emodi Wall.var.chinesis Sprague was established. The separation was performed with the following condition: column, Kromasil-C18, 5 μm, 15 × 0.46 cm; solvent A, 25 mM phosphate buffer, pH 2.5; solvent B, methanol; gradient, 50/50/70% B at 0/13/33 min; flow rate, 0.8 mL min?1; detection, UV 270 nm. β-Apopicropodophyllin was used as the internal standard. The samples of P. emodi Wall.var.chinesis Sprague from different sources were examined by the developed method. In addition, three methods for sample preparation were discussed. It is shown from the results that refluxing in chloroform displays high extraction efficiency. 相似文献
997.
The retention characteristics of 25 2-cyano-3-methylthio-3-substituted amine-acrylates are determined using reversed-phase thin-layer chromatography (RP-TLC) with methanol-water mixtures as eluents. The relationship between Rm values and partition coefficients (C log P) are established. The Rm values decrease linearly with increasing methanol concentration in the eluent. The Rm values extrapolated to zero organic modifier concentration (Rm0) in the eluent are highly related to C log P. The Rm0 value can be used to evaluate the lipophilicity of this kind of compound. 相似文献
998.
The calculations of clusters modeling the fluorine-doping and oxygen deficiency of YBa2Cu307 have been performed by the method of all-electronab initio Hartree-Fock with self-consistent crystal field. Results show that in CuO planes electric charge significantly increases,
the chemical valence of Cu decreases and the covalent bonding of Cu-O greatly weakens owing to oxygen deficiency, while the
effect of F restores the local electronic structure of YBa2Cu3O7. The reported opinion that F occupied the oxygen vacancy in Cu-O chains seems disputable according to the calculated bonding
characteristics
Project supported by the National Natural Science Foundation of China. 相似文献
999.
1000.
Runru Liu Dapeng Xu Shuang Li Zhe Lü Yanfeng Xue Deyong Wang Wenhui Su 《Frontiers of Chemistry in China》2006,1(4):398-401
In this paper, perovskite oxide SmCoO3 was prepared by the solid-state reaction method using Co2O3 and Sm2O3 as raw materials. The structure and properties of the samples were investigated by XRD, Raman spectral techniques, and DC
measurements and so on. The results of XRD and Raman spectra showed that the mixtures of Co2O3 and Sm2O3 can react to produce a single phase perovskite oxide SmCoO3 around 1353 K. The single-phase SmCoO3 changes from an insulator to a semi-conductor and transition occurs around 470 K. The thermal expansion coefficient (2.17
× 10−5 K−1) of the single-phase SmCoO3 is approximately equal to that of doped LaGaO3, but much bigger than that of SDC(Ce0.85Sm0.15O2) above 873 K. 相似文献