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961.
由多时间尺度耦合效应引起的簇发振荡行为是非线性动力学研究的重要课题之一.本文针对一类参数激励下的三维非线性电机系统(该系统可以描述两种自激同极发电机系统的动力学行为,两种系统在数学上等效),研究了当参数激励频率远小于系统自然频率时的各种复杂簇发振荡行为及其产生机理.通过快慢分析方法, 将参数激励作为慢变参数,得到了非自治系统对应的广义自治系统及快子系统和慢变量,并给出了快子系统的稳定性和分岔条件以及系统关于典型参数的单参数分岔图.借助转换相图与分岔图的叠加, 分析了对称式delayed subHopf/fold cycle簇发振荡的产生机理及其动力学转迁, 即delayed subHopf/fold cycle簇发振荡、焦点/焦点型对称式叉形分岔滞后簇发振荡和焦点/焦点型叉形分岔滞后簇发振荡.研究结果表明, 系统会出现两种不同的分岔滞后形式, 一种是亚临界Hopf分岔滞后,另一种是叉形分岔滞后,而且控制参数显著影响平衡点的稳定性和分岔滞后区间的宽度.同时初始点的选取则会影响系统动力学行为的对称性.本文的研究进一步加深了对由分岔滞后引起的簇发振荡的认识和理解. 相似文献
962.
963.
选用四种不同的分子筛(SAPO-34, ZSM-5, Y, MCM-41)与CuCoMn(高醇合成组元)构成双功能催化剂,利用N2吸脱附、H2-TPR、XRD、NH3-TPD等表征了催化剂的结构性质. 研究了催化剂在生物质基合成气一段法制取液态烃燃料的应用. 相比于CuCoMn催化剂,加入分子筛的双功能催化剂均不同程度地提高了液体烃燃料的选择性及收率,且收率按顺序递减呈CCM-ZSM-5>CCM-SAPO-34>CCM-Y>CCM-MCM-41. 同时,共沉淀法制备的CuCoMn-ZSM-5 (20wt%, Si/Al=100) 具有最佳的CO转化率(76%)及液体产物收率(30%). 相比于CuCoMn氧化物,双功能催化剂的比表面及孔容均得到提高. CCM-ZSM-5具有适中的微孔尺寸和中等强度的酸性,增加CCM-ZSM-5中ZSM-5含量或降低ZSM-5中的Si/Al比,均有利于提高酸性位的数量,主要是较弱的酸性位. 而共沉淀法制备的CCM-ZSM-5具有更好的金属分散性及还原性能. 相似文献
964.
965.
Estimation of pulsed laser-induced single event transient in a partially depleted silicon-on-insulator 0.18-μm MOSFET 下载免费PDF全文
In this paper, we investigate the single event transient(SET) occurring in partially depleted silicon-on-insulator(PDSOI) metal–oxide–semiconductor(MOS) devices irradiated by pulsed laser beams. Transient signal characteristics of a 0.18-μm single MOS device, such as SET pulse width, pulse maximum, and collected charge, are measured and analyzed at wafer level. We analyze in detail the influences of supply voltage and pulse energy on the SET characteristics of the device under test(DUT). The dependences of SET characteristics on drain-induced barrier lowering(DIBL) and the parasitic bipolar junction transistor(PBJT) are also discussed. These results provide a guide for radiation-hardened deep sub-micrometer PDSOI technology for space electronics applications. 相似文献
966.
Huiyu Xiong Huichang Bi Yuguang Wen Jinqing Hu Guoping Zhong Tianmiao Ou Zhishu Huang Rifang Liao Minjing Zhao Xiaoling Qin Min Huang 《Chromatographia》2011,73(11-12):1073-1080
A sensitive assay for determining SYUIQ-F5, a novel telomerase inhibitor and anti-tumor drug, in rat tissues and plasma was developed and validated by using liquid chromatography/tandem mass spectrometry (LC?CMS?CMS). After a single step liquid?Cliquid extraction with ethyl acetate-dichloromethane, SYUIQ-F5 and SUCL (internal standard) were subjected to LC?CMS?CMS analysis using positive electro-spray ionization under selected reaction monitoring mode. Chromatographic separation of SYUIQ-F5 and SUCL was achieved on a Zorbax Eclipse Plus C18 column (I.D. 4.6 mm × 150 mm, 3.5 ??m) with a mobile phase consisting of acetonitrile-2 mM ammonium formate (90:10, v/v) at a flow rate of 0.6 mL min?1. The intra- and inter-batch precision of the method were <12.2 and 8.7%, respectively. The intra- and inter-batch accuracies ranged from 100.2 to 107.3%. The lowest limit of quantification for SYUIQ-F5 was 0.5 ng mL?1. The method was applied to a SYUIQ-F5 tissue distribution study after an oral dose of 30 mg kg?1 to rats. SYUIQ-F5 tissue concentrations decreased in the order of small intestine> liver> lung> spleen> stomach> kidneys> heart> brain> muscle> fat> testes> plasma. SYUIQ-F5 could still be detected in most of the tissues at 48-h post-dosing. These results indicated that the LC?CMS?CMS method was sensitive, reliable, and specific to quantify SYUIQ-F5 in different rat tissues. 相似文献
967.
Zhongni Wang Jing Zhao Wu Zhou Xilian Wei Xiaolu Tang 《Journal of Dispersion Science and Technology》2013,34(4):546-552
Lamellar liquid crystals of the nonionic surfactant dodecyl polyoxyethylene (4) polyoxypropylene (5) ether (DEP) were investigated by means of phase diagram and rheological technique at 25°C in the presence of different solvents. The aqueous medium includes pure water, physiological saline and 20% sucrose solution, and the oil phase includes isopropyl myristate (IPM), oleic acid, and geraniol, which are all pharmaceutically accepted chemicals. The steady and dynamic rheological property analyses of the lamellar liquid crystals formed in DEP/H2O/IPM system indicate that the lamellar samples constructed by this special surfactant behave as pseudo-plastic fluid with relatively high elasticity and possess defects in their assembled structure. Also in this system, the elastic character gets decreased with increase in the water content. Furthermore, the comparison investigations show that the relatively high polar oil component increases the network strength of the lamellar phase, while increase in the polarity of water phase enhances the structure defects. 相似文献
968.
Xin-Hua Ma Yu-Jiang Bi Zhen Cao Ming-Jun Chen Song-Zhan Chen Yao-Dong Cheng Guang-Hua Gong Min-Hao Gu Hui-Hai He Chao Hou Wen-Hao Huang Xing-Tao Huang Cheng Liu Oleg Shchegolev Xiang-Dong Sheng Yuri Stenkin Chao-Yong Wu Han-Rong Wu Sha Wu Gang Xiao Zhi-Guo Yao Shou-Shan Zhang Yi Zhang Xiong Zuo 《中国物理C(英文版)》2022,(3):1-35
The Large High Altitude Air Shower Observatory (LHAASO) (Fig.1) is located at Mt.Haizi (4410 m a.s.l.,600 g/cm2,29° 21'27.56" N,100° 08'19.66" E) in Daocheng,Si... 相似文献
969.
Facet effect of single-crystalline Ag3PO4 sub-microcrystals on photocatalytic properties 总被引:2,自引:0,他引:2
We recently reported that Ag(3)PO(4) exhibits excellent photooxidative capabilities for O(2) evolution from water and organic dye decomposition under visible-light irradiation. However, very little is known about the shape and facet effects of Ag(3)PO(4) crystals on their photocatalytic properties. Herein we have developed a facile and general route for high-yield fabrication of single-crystalline Ag(3)PO(4) rhombic dodecahedrons with only {110} facets exposed and cubes bounded entirely by {100} facets. Moreover, studies of their photocatalytic performance have indicated that rhombic dodecahedrons exhibit much higher activities than cubes for the degradation of organic contaminants, which may be primarily ascribed to the higher surface energy of {110} facets (1.31 J/m(2)) than of {100} facets (1.12 J/m(2)). 相似文献
970.
栀子苷在乙腈水体系中诱导相分离分配行为 总被引:1,自引:0,他引:1
研究了栀子乙腈水提取液中的栀子苷在诱导相分离后在两相中的分配行为,建立了乙腈/水分相体系分离纯化栀子苷的新方法。 重点考察了能使乙腈/水体系分相的诱导剂的种类,分析了诱导剂的组成比例以及用量、乙腈的体积分数、样品加入量和温度对栀子苷分配行为的影响。 当温度为25 ℃时,栀子的乙腈/水(体积比1∶1)提取液中加入KCl与MgSO4组成的混盐(质量比2∶1)分相诱导剂后,栀子苷的萃取率达到81.63%,含量由分相前的3.05%提高至13.54%。 相似文献