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951.
952.
953.
The influences of steady aerodynamic loads on hunting stability of high-speed railway vehicles were investigated in this study.A mechanism is suggested to explain the change of hunting behavior due to actions of aerodynamic loads:the aerodynamic loads can change the position of vehicle system(consequently the contact relations),the wheel/rail normal contact forces,the gravitational restoring forces/moments and the creep forces/moments.A mathematical model for hunting stability incorporating such influences was developed.A computer program capable of incorporating the effects of aerodynamic loads based on the model was written,and the critical speeds were calculated using this program.The dependences of linear and nonlinear critical speeds on suspension parameters considering aerodynamic loads were analyzed by using the orthogonal test method,the results were also compared with the situations without aerodynamic loads.It is shown that the most dominant factors a ff ecting linear and nonlinear critical speeds are different whether the aerodynamic loads considered or not.The damping of yaw damper is the most dominant influencing factor for linear critical speeds,while the damping of lateral damper is most dominant for nonlinear ones.When the influences of aerodynamic loads are considered,the linear critical speeds decrease with the rise of cross wind velocity,whereas it is not the case for the nonlinear critical speeds.The variation trends of critical speeds with suspension parameters can be significantly changed by aerodynamic loads.Combined actions of aerodynamic loads and suspension parameters also a ff ect the critical speeds.The effects of such joint action are more obvious for nonlinear critical speeds. 相似文献
954.
Qinglin Sheng Ruixiao Liu Jianbin Zheng Wanghua Lin Yuanyao Li 《Journal of Solid State Electrochemistry》2012,16(2):739-745
The direct electron transfer of glucose oxidase (GOD) immobilized on a composite matrix based on porous carbon nanofibers
(PCNFs), room-temperature ionic liquid (RTIL), and chitosan (CHIT) underlying on a glassy carbon electrode was achieved. The
combination of the PCNFs, RTIL, and CHIT provided a suitable microenvironment for GOD to transfer electron directly. In deaerated
buffer solutions (pH 7.0), the cyclic voltammetry of the GOD/PCNFs/RTIL/CHIT composite films showed a pair of well-defined
redox peaks with the formal potential of −0.45 V (vs. SCE). The synergistic effort of the PCNFs, RTIL, and CHIT also promoted
the stability of GOD in the composite film and retained its bioactivity. 相似文献
955.
X. J. Cheng B. X. Jiang L. Li J. L. Wang Zh. G. Yang W. B. Cheng X. Ch. Shi Y. B. Pan 《Laser Physics》2012,22(4):652-655
Lasers from Yb:YAG ceramic at different temperature were reported in this paper. The Yb:YAG ceramic laser with active-mirror
structure was end-pumped by a laser diode whose central wavelength was 940 nm. At 80 K, with doping concentration of 5 at
% Yb:YAG ceramic slab, output energy of 0.68 J at 10 Hz repetition rate was obtained under the pump energy of 2.49 J, corresponding
to a slope efficiency of 40% and a conversion efficiency of 27.3%, respectively. 相似文献
956.
957.
Lihua Zuo Heng Meng Jingjing Wu Zhen Jiang Shuying Xu Xingjie Guo 《Journal of separation science》2013,36(3):517-523
In this study, the enantioseparation of zopiclone, repaglinide, chlorphenamine maleate, brompheniramine maleate, dioxopromethazine hydrochloride, promethazine hydrochloride, liarozole, carvedilol, homatropine hydrobromide, homatropine methylbromide, venlafaxine, and sibutramine hydrochloride has been investigated using β‐CD in combination with a chiral ionic liquid (IL), 1‐ethyl‐3‐methylimidazolium‐L‐lactate. The influence of the type of IL and its concentration, BGE pH, and chain length of the IL cations on the resolution are discussed. Finally, the proposed method was successfully applied for the chiral impurity determination of eszopiclone in pharmaceutical tablets after validation with respect to accuracy and precision, linearity range, selectivity, repeatability, LOD and LOQ. It is assessed that the chiral impurity determination in the commercial tables is fewer than 0.1%. 相似文献
958.
Yi Yuan Zong-Lin Jiang Jia-Ming Yan Ge Gao Albert S. C. Chan Ru-Gang Xie 《合成通讯》2013,43(24):4555-4561
Two new macrobicyclic imidazolium and benzimidazolium phanes were synthesized by direct quaternization of the corresponding tripodal azacycles with tribromide under high dilution condition in excellent yields. The cyclophanes were identified by 1H-NMR, 13C-NMR, FAB-MS, IR, elemental analysis and X-ray diffraction analysis. 相似文献
959.
Jiang Bolong Muddemann Thorben Kunz Ulrich Haupt Dennis Bormann Hinnerk Niedermeiser Michael Schläfer Ottmar Sievers Michael 《Research on Chemical Intermediates》2018,44(1):639-655
Research on Chemical Intermediates - Effective methods for graphite felt (GF) treatment based on Fenton’s reagent treatment and thermal modification have been used to improve microbial fuel... 相似文献
960.
A Pd-catalyzed haloallylation of alkynes with allyl alcohols in ionic liquids has been reported. Both chloroallylation and bromoallylation can be easily carried out with high selectivity. A variety of 1,4-dienes were formed in moderate to excellent yields. The reaction system of the Pd catalyst as well as the ionic liquid can be recycled for several times. And the ionic liquid acts as not only a solvent in the reaction, but also provides the excess halide ions to control Z/E selectivity and acts as a ligand inhibit the β-hydride elimination. 相似文献