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41.
The limit cycle of a class of strongly nonlinear oscillation equations of the form % MathType!MTEF!2!1!+-% feaafeart1ev1aaatCvAUfeBSjuyZL2yd9gzLbvyNv2CaerbuLwBLn% hiov2DGi1BTfMBaeXafv3ySLgzGmvETj2BSbqefm0B1jxALjhiov2D% aebbfv3ySLgzGueE0jxyaibaiGc9yrFr0xXdbba91rFfpec8Eeeu0x% Xdbba9frFj0-OqFfea0dXdd9vqaq-JfrVkFHe9pgea0dXdar-Jb9hs% 0dXdbPYxe9vr0-vr0-vqpWqaaeaabiGaciaacaqabeaadaqaaqGaaO% qaaiqadwhagaWaaiabgUcaRmXvP5wqonvsaeHbbjxAHXgiofMCY92D% aGqbciab-DgaNjab-HcaOiaadwhacqWFPaqkcqWF9aqpcqaH1oqzca% WGMbGaaiikaiaadwhacaGGSaGabmyDayaacaGaaiykaaaa!50B8!\[\ddot u + g(u) = \varepsilon f(u,\dot u)\] is investigated by means of a modified version of the KBM method, where is a positive small parameter. The advantage of our method is its straightforwardness and effectiveness, which is suitable for the above equation, where g(u) need not be restricted to an odd function of u, provided that the reduced equation, corresponding to =0, has a periodic solution. A specific example is presented to demonstrate the validity and accuracy of our 09 method by comparing our results with numerical ones, which are in good agreement with each other even for relatively large . 相似文献
42.
剖析了传统普通物理实验教学的缺陷,论述了“两循环三层次”教学模式的内容和实施过程,科学总结了教学改革取得的成果。 相似文献
43.
We consider a certain combinatorial game on a digraph for two cases of the price function. For one case the game in question extends the cyclical game studied in Ehrenfeucht and Mycielski (1979) and Gurvitch, Karzanov and Khachiyan (1988) which, in its turn, is a generalization of the well-known problem of finding a minimum mean cycle in an edge-weighted digraph. We prove the existence of optimal uniform stationary strategies for both cases and give algorithms to find such strategies.This work was partially supported by Chaire municipale, Mairie de Grenoble. 相似文献
44.
In recent hundred years the annual discharge variations of the Changjiang River (represented by the Yichang station) and the Huanghe River (represented by Shanxian and Tangnaihe, respectively) have closely related to the geographical distribution of the earthquakes coming about in China in the same year, Both the occurrence of the destructive seism or seismic swarm in the river basins and the disappearance of the shocks in the east and south of the basins are the conditions that the Changjiang and Huanghe Rivers are the high flow while that the strong earthquake of magnitude 7 or more occurred in North China is the condition for the Changjiang low flow year and that of 6 or more in the Qilian Mountains area is for the Huanghe River. In the latter part of this paper, a 2-year sample is given to explain that the conditions of the 2 rivers being high flow years are that the north-south seismic belt is active and in the meanwhile no seism occurred in South China, and those of the low flow year are that the 相似文献
45.
土壤环境中铅的化学 总被引:3,自引:0,他引:3
谢正苗 《广东微量元素科学》1996,3(11):24-28
论述了环境中铅的背景值、来源、污染、质量标准、化学循环以及环境中铅的烷基化,为铅污染治理提供理论依据。 相似文献
46.
Valery P. Nesterenko 《Journal of Thermal Analysis and Calorimetry》2005,80(3):575-577
Summary On the basis of calorimetric research of selenium dioxide, zirconium dioxide and zirconium diselenite dissolution reactions in the hydrofluoric acid solution under 298 K a standard enthalpy of Zr(SeO3)2 formation reaction from ZrO2 and SeO2 and a standard enthalpy of zirconium diselenite formation have been obtained. The value of enthalpy has been equal to -58.1±3.43 kJ mol-1 in ZrO2(solid)+2SeO2(solid) Zr(SeO3)2(solid) reaction. The standard enthalpy of zirconium diselenite formation is equal to Hf,2980Zr(SeO3)2(solid)= -1603.2±3.8 kJ mol-1. The Hf,2980 Zr(SeO3)2(solid) value has been determined for the first time. 相似文献
47.
Optimal design and operation of bioreactors for insect cell culture is facilitated by functional relations providing quantitative
information on cellular metabolite consumption kinetics, as well as on the specific cell growth rates (μG). Initial specific consumption rates of glucose, malate, and oxygen, and associated changes in μG, were measured forSpodoptera frugiperda clone 9 (Sf9) cells grown in batch suspension culture in medium containing 7–35 mM glucose, 0–16 mM malate, and 4–16 mM glutamine.
The initial specific glucose consumption rate (q
G
) could be described by a modified Michaelis-Menten equation treating malate as a “competitive” inhibitorK
1 = 6.5 mM) and glutamine as a “noncompetitive” inhibitorK
I
= 14 mM) ofq
G
, with aK
m
of 7.1 mM for glucose. All three carbon sources were found to increase μG in a saturable manner, and a modified Monod equation was employed to describe this relationship (μGmax = 0.047 h-1). The initial specific oxygen consumption rate (qO2) in Sf9 cells could be related to μG by the maintenance energy model, and it was calculated that, under typical culture conditions, about 15–20% of the cellular
energy demand comes from functions not related to growth. Fitted parameters in mathematical expression for μg: K4, Monod constant for glucose (mM); K5, modified Monod constant for malate (mM); K6, Monod constant for glutamine (mM); mo2, specific consumption rate of oxygen by the cells under zero-growth conditions (nmol/cell/h); qF, initial specific fumarate production rate (nmol/cell/ h);q
G
, initial specific glucose consumption rate (nmol/cell/h); qGmax, maximum initial specific glucose consumption rate (nmol/cell/h);q
M
, initial specific malate consumption rate (nmol/cell/h); qo2, initial specific oxygen consumption rate (nmol/cell/h); Yo2, cell yield on oxygen (cells/nmol); μ, initial specific cell growth rate (h-1); μg, initial specific cell growth rate (h-1); μGmax, maximum initial specific cell growth rate (h-1). 相似文献
48.
49.
The fast trace analysis method used to monitor 2,3,7,8-TCDD in stack gas during the incineration of the waste from Seveso is described. The sampling of volatile organic compounds from flue gases, distributed between all three aggregation states, is based on a micromethod developed for the trace analysis of water using a specially dimensioned adsorptive charcoal filter (1.5 mg charcoal). In conjunction with subsequent GC/MS measurements the rapid “fast cycle trace analysis” ensured specific 2,3,7,8-TCDD detection down to 100 pg per m3 flue gas in cycle times of about 1–2 hours. 相似文献
50.
通过对工业系统和热力系统的对比分析,提出运用热力学原理来诠释清洁生产的理论.在此基础上.对工业生产的三种模式和清洁生产的评价体系进行热力学解释,并将热力循环运用于清洁生产,试图从热力学原理中找到清洁生产理论的新突破。 相似文献