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991.
Lang Liu Dianzeng Jia Yongmin Qiao Yali Ji Kaibei Yu 《Journal of chemical crystallography》2002,32(8):255-259
A novel Schiff base compound, N-(1-phenyl-3-methyl-4-benzal-pyrazolone-5)-salicylidene hydrazine (PMBP-SAH), has been synthesized and characterized by X-ray diffraction: monoclinic, space group C2/c with a = 21.796(5) Å, b = 18.370(3) Å, c = 20.843(3) Å, = 95.440(10)°, V = 8308(3) Å3, and Z = 16. The title compound contains two kinds of tautomers: the red compound is the keto form and the other is the enol form. Changes in color are due to the isomerization of the enol and keto forms by the intramolecular proton transfer. 相似文献
992.
证明了四阶边值问题y(4) =λα( x) f ( y( x) ) , 0 0且充分小时正解的存在性 .其中 ,α:[0 ,1 ]→ R连续 ,f ( 0 ) >0 .本文的工具是L eray- Schauder不动点定理 [4] . 相似文献
993.
994.
The stress-induced martensitic transformation and its relation with crack nucleation and propagation in CuNiAl shape memory alloy were investigated through in-situ tensile tests by SEM and TEM. The results indicated that the stress concentration ahead of the crack tip could induce formation of stacking faults and different types of martensites. TEM observations showed that the martensites could transform from one type to another and even reversely to the parent during loading. The microcracks nucleated along the martensite/parent interface and intersection between two martensites. When the crack propagated a certain distance, the stress concentration ahead of the crack tip was large enough to result in formation of slip bands, and in this condition the microcrack nucleated along slip bands more easily. 相似文献
995.
Ming‐Song Yang Li‐Wen Xu Fei‐Bao Zhang Hua‐Yu Qiu Jian‐Xiong Jiang Guo‐Qiao Lai 《应用有机金属化学》2008,22(3):177-180
FeCl3 was found to be an active catalyst for the one‐pot allylation reaction of aromatic aldehydes with allyltriethoxysilane under mild and simple conditions, which resulted in the direct synthesis of homoallyl ethers with very high chemoselectivity and yields. Various types of homoallyl ethers were obtained in excellent yields (up to 99%). Copyright © 2008 John Wiley & Sons, Ltd. 相似文献
996.
997.
Considering the Julia set J(Tλ) of the Yang-Lee zeros of the Potts model on the diamond hierarchical Lattice on the complex plane, the authors proved that HDJ(Tλ) 〉 1 and discussed the continuity of J(Tλ) in Hausdorff topology for λ∈R. 相似文献
998.
OntheInvolutiveSolutionsofSolitionHierarchy乔志军OntheInvolutiveSolutionsofSolitionHierarchy¥QiaoZhijun(Dept.ofMath,LiaonignUniv... 相似文献
999.
1000.
Jing‐Zheng Song Chun‐Feng Qiao Song‐Lin Li Quan‐Bin Han Hong‐Xi Xu 《Journal of separation science》2008,31(22):3809-3816
Experimental design and response surface methodology have been used for the development of the stability‐indicating HPLC method for the purity determination of yunaconitine reference standard. Significant factors including the contents of ACN, perchloric acid, triethylamine (TEA), and column temperature were optimized using a Box–Behnken design. A mixture of crude yunaconitine extract and degradation solutions of yunaconitine under stress conditions was chromatogramed. The normalized peak area of total impurities, the retention time of yunaconitine, and the resolutions between yunaconitine and its adjacent peaks were selected as optimization criteria. Derringer desirability function of the multicriteria and the tested factors were used to establish 3‐D response surfaces. The optimal condition was achieved with a mobile phase of ACN/water (30:70, containing 0.125% perchloric acid and 1.0% TEA) at a column temperature of 37.5°C. The method was validated and shown comparable to that of phase solubility analysis. As a result, the newly developed method can be used to determine the chromatographic purity and stability of the yunaconitine reference standard. 相似文献