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排序方式: 共有102条查询结果,搜索用时 31 毫秒
1.
YBa2Cu3O7-δ and Tl2Ba2CaCu2O8 thin films for microwave filters were synthesized by pulsed laser deposition and the two-step thalliation process. Substrate
quality requirements and the relation of thin film morphology, microstructure with microwave surface resistance were discussed. 相似文献
2.
本文研究了数值求解非自治随机微分方程的正则Euler-Maruyama分裂(CEMS)方法,该方程的漂移项系数带有刚性且允许超线性增长,扩散项系数满足全局Lipschitz条件.首先,证明了CEMS方法的强收敛性及收敛速度.其次,证明了在适当条件下CEMS方法是均方稳定的.进一步,利用离散半鞅收敛定理,研究了CEMS方法的几乎必然指数稳定性.结果表明,CEMS方法在漂移系数的刚性部分满足单边Lipschitz条件下可保持几乎必然指数稳定性.最后通过数值实验,检验了CEMS方法的有效性并证实了我们的理论结果. 相似文献
3.
p-tert-Butylcalix[8]arene bonded capillaries for open-tubular capillary electrochromatography were prepared with γ-glycidoxypropyltrimethoxysilane as a bridge. The bonded capillary displayed low and steady electroosmotic flow (EOF) values over the pH range from 4 to 9. Detection limits for direct spectrophotometric detection at 277 nm for benzenediols (at a signal to noise ratio of 2) were 0.96 mg l−1 for the unbonded capillary and 1.48 mg l−1 for the bonded capillary, showing that the bonded layer did not show significant absorbance and hence decreased sensitivity. The bonded capillaries showed good separation selectivity for o-, m- and p-benzenediols, α- and β-naphthols, and α- and β-naphthylamines. This selectivity was attributed to significant interactions between the analytes and the bonded p-tert-butylcalix[8]arene, which contributed to the electrochromatographic separation mechanism. The bonded capillaries gave high stability and reproducibility. 相似文献
4.
HUANG Wei-Ping ZHANG Xin-Jie WU Shi-HuaMA Shu-Yin ZHANG Shu-Ji ZHAO Wei-Jun 《天然气化学杂志》1997,6(3):252-257
IntroductionIn1962,N.V.Kutepow'SgroupfirstusedcomplexesofFe,CoandNiascatalyststocatalyzecarboXylationofethanoltopreparepropanoicacidanditsderivants.Thereactionpressurewashighandtheyieldwaslow.LateronPaulalsandhiscolleagueusedabC13andiodineascatalyst,which… 相似文献
5.
Zhong Lvling Li Baolin Zhang Liang Ma Xinjie Chai Shouning 《Russian Journal of Physical Chemistry A, Focus on Chemistry》2018,92(4):785-792
Russian Journal of Physical Chemistry A - A new mesoporous carbon containing nitrogen and copper was prepared by carbonizing a polymer obtained by blending p-phenylenediamine, copper(II) sulfate,... 相似文献
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Xinjie GaiRonald Grigg Ines KöppenJohn Marchbank Visuvanathar Sridharan 《Tetrahedron letters》2003,44(40):7445-7448
A novel palladium catalysed three-component cascade process is described involving allenylation of an aryl iodide to generate a (π-allyl)palladium species which is intercepted by a carbon or nitrogen nucleophile followed by intramolecular Michael addition to afford carbo- and heterocycles in good yield. 相似文献
10.
Xinjie Zhang Yunqing Gong Gang Yu Youchang Xie 《Journal of molecular catalysis. A, Chemical》2002,180(1-2):293-298
Oxygen species on fresh and treated NiO/Al2O3 and their activities for oxidation of ethane and ethylene were investigated using catalytic property measurements, ethane and ethylene pulse experiments and O2–TPD–MS experiments. The results revealed that there are two kinds of active oxygen species (the more active one and the less active one) on fresh NiO/Al2O3 catalyst, but there is only one active oxygen species, the less active one, on treated NiO/Al2O3 catalyst. The more active oxygen species can convert ethane or ethylene to carbon dioxide by one step while the less active one can only convert ethane to ethylene, but cannot convert ethane and/or ethylene to carbon dioxide. The more active oxygen species can be removed from the catalyst by heating from 350 to 850 °C. The amounts of desorption oxygen on the catalysts are proportional to their selectivity to carbon dioxide. 相似文献