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471.
粘弹性体力学模型的判别准则及在岩石试验中的应用 总被引:3,自引:2,他引:3
从粘弹性介质的蠕变柔量出发,推导出粘弹性体力学模型的判别准则。并通过单轴压缩条件下4种岩石的蠕变试验,讨论了判别准则实用化中的两个问题,解的存在条件问题,多解性及解的唯一性问题。 相似文献
472.
作者研究差分方程Δnx (t) + p (t)Δn-1x(t) + H (t,x(g(t) ) ) =0 ,其中 P∶ D→ R,H∶ D×R→ R,0≤ p (t)≤ 1,g∶ D→ D,limt→∞t∈ Dg(t) =∞ ,D={ t0 ,t0 + 1,t0 + 2 ,… } .得到保证这个方程的一切解都振动的若干充分条件 相似文献
473.
We consider the ordinary differential equation of the second order, which describes oscillations of a satellite with respect
to its mass center moving along an elliptic orbit with eccentricity e. The equation has two parameters: e and μ. It is regular for 0 ≤ e < 1 and singular when e = 1. For
1 we obtain three limit problems. Their bounded solution to the first limit problem form a two-dimensional (2D) continuous
invariant set with a periodic structure. Solutions to the second limit problem form 2D and 3D manifolds. The μ-depending families
of odd bounded solutions are singled out. One of the families is twisted into a self-similar spiral. To obtain the limit families
of the periodic solutions to the original problem match together the odd bounded solutions to the first and the second limit
problem. The point of conjunction is described by the third (the basic) limit problem. The limit families are very close to
prelimit ones computed in earlier studies.
This revised version was published online in July 2006 with corrections to the Cover Date. 相似文献
474.
In view of the uncertainty of the origin of the secular increase of N2O, we studied heterogeneous processes that contribute to formation of N2O in an environment that comes as close as possible to exhaust conditions containing NO and SO2, among other constituents. The N2O formation was followed using electron capture gas chromatography (ECD-GC). The other reactants and intermediates (SO2, NO, NO2 and HONO) were monitored using gas phase UV-VIS absorption spectroscopy. Experiments were conducted at 298 and 368 K as well as at dry and high humidity (approaching 100% rh) conditions. There is a significant heterogeneous rate of N
2
O formation at conditions that mimic an exhaust plume from combustion processes.The simultaneous presence of NO, SO2, O2 in the gas phase and condensed phase water, either in the bulk liquid or adsorbed state has been confirmed to be necessary for the production of significant levels of N2O. The stoichiometry of the overall reaction is: 2 NO+SO2+H2O N2O+H2SO4. The maximum rate of N2O formation occurred at the beginning of the reaction and scales with the surface area of the condensed phase and is independent of its volume. A significant rate of N2O formation at 368 K at 100% rh was also observed in the absence of a bulk substrate. The diffusion of both gas and liquid phase reactants is not rate limiting as the reaction kenetics is dominated by the rate ofN2O formation under the experimental conditions used in this work. The simultaneous presence of high humidity (90–100% rh at 368 K) and bulk condensed phase results in the maximum rate and final yield of N2O approaching 60% and 100% conversion after one hour in the presence of amorphous carbon and fly-ash, respectively.Work performed in partial fulfillment of the requirements of Dr ès Sciences at EPFL. 相似文献
475.
Simplified algorithms for calculating double-couple rotation 总被引:3,自引:0,他引:3
Yan Y. Kagan 《Geophysical Journal International》2007,171(1):411-418
We derive new, simplified formulae for evaluating the 3-D angle of earthquake double-couple (DC) rotation. The complexity of the derived equations depends on both accuracy requirements for angle evaluation and the completeness of desired solutions. The solutions are simpler than my previously proposed algorithm based on the quaternion representation designed in 1991. We discuss advantages and disadvantages of both approaches. These new expressions can be written in a few lines of computer code and used to compare both DC solutions obtained by different methods and variations of earthquake focal mechanisms in space and time. 相似文献
476.
EARTHQUAKE FOCAL MECHANISM AND ITS TECTONIC SIGNIFICANCE ALONG THE TWO SIDES OF THE RED RIVER FAULT ZONE 总被引:1,自引:0,他引:1
The Red River Fault Zone is a gigantic slide-slip fault zone extending up to 1000km from Tibet to South China Sea. It has been divided into the north, central and south segments according to the difference of the geometry, kinetics, and seismicity on the land, but according to the contacted relationship between the old pre-Cenozoic block in Indochina Peninsula and the South China block, the Red River Fault Zone was divided into two parts extending from land to ocean, the north and south segments. Since the Tertiary, the Red River Fault Zone suffered first the sinistral movement and then the dextral movement. The activities of the north and the south segments were different. Based on the analysis of earthquakes and focal mechanism solutions, earthquakes with the focus depths of 0-33km are distributed over the whole region and more deep earthquakes are distributed on the northeastern sides of the Red River fault. Types of faulting activities are the thrust in the northwest, the normal in the north and the 相似文献
477.
478.
479.
480.
Jesús Carrera Xavier Sánchez-Vila Inmaculada Benet Agustín Medina Germán Galarza Jordi Guimerà 《Hydrogeology Journal》1998,6(1):178-190
Matrix diffusion has become widely recognized as an important transport mechanism. Unfortunately, accounting for matrix diffusion
complicates solute-transport simulations. This problem has led to simplified formulations, partly motivated by the solution
method. As a result, some confusion has been generated about how to properly pose the problem. One of the objectives of this
work is to find some unity among existing formulations and solution methods. In doing so, some asymptotic properties of matrix
diffusion are derived. Specifically, early-time behavior (short tests) depends only on φ
m
2
R
m
D
m
/ L
m
2, whereas late-time behavior (long tracer tests) depends only on φ
m
R
m
, and not on matrix diffusion coefficient or block size and shape. The latter is always true for mean arrival time. These
properties help in: (a) analyzing the qualitative behavior of matrix diffusion; (b) explaining one paradox of solute transport
through fractured rocks (the apparent dependence of porosity on travel time); (c) discriminating between matrix diffusion
and other problems (such as kinetic sorption or heterogeneity); and (d) describing identifiability problems and ways to overcome
them.
Received, October 1997 · Revised, November 1997 · Accepted, December 1997 相似文献