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991.
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
992.
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
993.
994.
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
995.
OntheInvolutiveSolutionsofSolitionHierarchy乔志军OntheInvolutiveSolutionsofSolitionHierarchy¥QiaoZhijun(Dept.ofMath,LiaonignUniv... 相似文献
996.
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
997.
998.
Zhanping Qiao Jianguo Chen Lihong Zhuo Shushen Zhang 《Russian Journal of Inorganic Chemistry》2008,53(3):450-454
The equilibrium solubility of the quaternary system CsBr-CeBr3-HBr(12.52 wt %)-H2O was determined at 298K and the corresponding equilibrium diagram was constructed. The quaternary system is complicated by
three equilibrium solid phases: CsBr, Cs5Ce2Br11 · 22H2O (5: 2 type), and CeBr3 · 7H2O, of which the new compound Cs5Ce2Br11 · 22H2O was found to be incongruently soluble in the system. The new compound obtained was identified and characterized by the method
of X-ray diffraction and the thermal analysis methods of thermogravimetry-differential thermogravimetry (TG-DTG), and it loses
its crystal water in two steps from 325 to 511 K. The standard molar enthalpy of solution of Cs5Ce2Br11 · 22H2O in deionized water was measured to be (129.105 ± 0.150) kJ mol−1 with a heat conduction microcalorimeter. The standard molar enthalpy of formation was calculated as (−10438.215 ± 0.150)
kJ mol−1.
This article was submitted by the authors in English. 相似文献
999.
A new free recoverable and reusable mono-alkaloid-type ligand has been synthesized by a simple method.With highly polar groups,the ligand can be recycled and reused eight times to prepare ethyl(2R,3S)-2,3-dihydroxy-3-phenylpropionate with high yield and ee via asymmetric dihydroxylation(AD) reaction. 相似文献
1000.
The efficient synthesis of N-(diphenylmethylene) glycine alkyl esters was achieved for the first microwave irradiation under solvent-free condition,using PEG or quaternary ammonium salts as phase transfer catalysts(PTCs).Under the optimum conditions, N-(diphenylmethylene) glycine alkyl esters were obtained in excellent yields in most cases. 相似文献