17 resultados para Passenger Miles Traveled.
em Chinese Academy of Sciences Institutional Repositories Grid Portal
Resumo:
通过数值求解由Miles导出的目前公认的非传播弧立波的控制方程——一个带复共轭项的非线性立方Schroedinger方程,对非传播弧立波进行研究。讨论了Miles方程中的线性阻尼系数α的值,计算表明,线性阻尼α对形成稳定的非传播弧立波影响很大,Laedke等人关于非传播弧立波的稳定性条件只是一个必要条件,而不是充分条件。模拟了两个非传播弧立波的相互作用,数值模拟表明,两个波的作用模式依赖于系统的参数,对不同的初始扰动及其演化的计算表明,只有适当的初始扰动才能形成单个稳定的非传播弧立波,否则扰动可能消失或发展成多个孤立波。
Resumo:
Standing soliton was studied by numerical simulation of ifs governing equation, a cubic Schrodiger equation with a complex conjugate term, which was derived by Miles and was accepted. The value of linear damping in Miles equation was studied. Calculations showed that linear damping effects strongly on the formation of a standing soliton and Laedke and Spatschek stable condition is only a necessary condition, but not a sufficient one. The interaction of two standing solitons was simulated. Simulations showed that the interaction pattern depends on system parameters. Calculations for the different initial condition and its development indicated that a stable standing soliton can be fanned only for proper initial disturbance, otherwise the disturbance will disappear or develop into several solitons.
Resumo:
The oscillatory thermocapillary convection and hydrothermal wave in a shallow liquid layer, where a temperature difference is applied between two parallel sidewalls, have been numerically investigated in a two-dimensional model. The oscillatory thermocapillary convection and hydrothermal wave appear if the Marangoni number is larger than a critical value. The critical phase speed and critical wave number of the hydrothermal wave agree with the ones given analytically by Smith and Davis in the microgravity environment, and it travels in the direction opposed to the surface flow. Another wave traveled downstream in addition to the hydrothermal wave traveled upstream was observed in the case of earth gravity condition.
Resumo:
通过数值求解由Miles导出的目前公认的非传播孤立波的控制方程——一个带复共轭项的非线性立方Schr〖AKo¨〗dinger方程,对非传播孤立波进行研究.讨论了Miles方程中的线性阻尼系数α的值,模拟了两个非传播孤立波的相互作用,数值模拟表明,两个波的作用模式依赖于系统的参数,对不同的初始扰动及其演化的计算表明,只有适当的初始扰动才能形成单个稳定的非传播孤立波,否则扰动可能消失或发展成多个孤立波.
Resumo:
客运架空索道线路支架的有限元计算是其结构设计的难点和重点,文中就线路支架的结构分析中有线元力学模型的简化,计算工况的确定以及计算方法等进行了讨论。最后给出了分析算例。
Resumo:
客运架空索道系统的固有频率与模态是衡量索道系统固有动力特性的重要指标,固有频率的大小直接关系到结构在各种不同的激励条件下是否会发生动力放大效应与共振。文中首先解决索道系统分析中的有限元建模问题,包括典型柔性索道的模型状态,然后利用ANSYS程序的子空间迭代法求出结构最低各阶的特征值与特征向量,并计算出三种工况下的前40阶固有频率与振动模态,为客运架空索道系统的动力特性分析提供有效的计算方法。
Resumo:
给出了用来分析客运架空索道线路支架极限承载力的一种有效的有限元分析方法,重点讨论使用该方法的具体分析过程,同时给出了编程框图,最后通过实例作了进一步的说明。
Resumo:
非传播孤立波是近年来由中国学者发现的一种独特的孤立水波。本文通过数值求解非传播孤立波目前公认的控制方程-Miles导出的一个带共轭项的非线性立方Schrodinger方程,对非传播孤立波进行数值模拟。本文针对非传播孤立波的各种性质,作了大量的数值计算工作,并与实验观察的现象及人们对非传播孤立波的理论研究结果进行了比较和分析。为了得到稳定的非传播孤立波,本文讨论了Miles方程中的线性阻尼系数a的值,计算表明,线性阻尼a对能否形成稳定的非传播孤立波影响很大,在某些情况下,Laedke等人提出的Miles方程的非传播孤立波解的稳定性条件与我们对Miles方程的数值模拟的结果相当一致,a可在满足稳定性条件的区间内取值,但也发现在某些情况下Laedke等人的稳定性条件与我们的数值模拟不完全符合,证明Laedke等人关于非传播孤立波的稳定性条件只是一个必要条件,而不是充分条件。本文研究了两个非传播孤立波的相互作用,数值模拟表明,两个波的作用模式依赖于系统的参数,只有适当大小的外驱动频率和振幅及线性阻尼a可算出两个非传播孤立波周而复始的相互作用现象来,参数不合适时,两个波可能最终合并为一个非传播孤立波而不再分离,也可能彼此不发生作用,保持各自的独立。对不同的初始扰动及其演化的计算表明,要形成单个稳定的非传播孤立波,则初始扰动必须适当,否则扰动可能消失或发展成多个孤立波。关于形成非传播孤立波所需的外驱动条件,计算结果表明,只有适当大小的外驱动频率和振幅可形成稳定的非传播孤立波,数值结果可以描述驱动频率的上限和驱动振幅的上下限,但无法描述驱动频率的下限。我们的数值模拟工作说明Miles方程确实较好的描述了非传播孤立波的物理模型,该方程可以解释许多关于非传播孤立波的物理特性。但Miles方程无法对非传播孤立波的某些实验现象作出解释,因而有待于进一步研究改进。
Resumo:
We studied the ranging behavior of a habituated group of black crested gibbons (Nomascus concolor jingdongensis) in a high, seasonal habitat on Mt. Wuliang, central Yunnan, China, between March 2005 and April 2006. Our results indicated that the total home range size for the study group was 129 ha, or 151 ha if the lacunae within the borders in which gibbons were not observed were included. This is a much bigger range size than that of other gibbon species. However, 69.7% of their activities occurred within 29 ha. The intensity of quadrant use was significantly correlated with the distribution of important food patches. The mean yearly daily path length was 1,391 m. Gibbons traveled farther when they spent more time feeding on fruit. To avoid often passing through ridges with little food, gibbons usually stayed in the same valley for successive days, and then moved on to another valley for another several days, which resulted in a concentrated ranging pattern.
Resumo:
We studied social organization, behavior, and range use of the Yunnan snub-nosed monkey (Rhinopithecus bieti) at Wuyapiya (99 degrees 12'E, 28 degrees 30'N, the People's Republic of China) over 12 months between May 1992 and June 1994. The Wuyapiya band contained greater than or equal to 175 members and had two levels of social organization. At one level, the monkeys formed multifemale, one-male units (OMUs) similar to those of many other colobines. At another level, 15 to 18 OMUs traveled together in a cohesive band. Unlike the bands of other species of Rhinopithecus, the Wuyapiya band of R. bieti did not show seasonal fission-fusion, although some social behavior, such as male-male aggression, was seasonal. With regard to range use, the Wuyapiya band had a large home range and long daily travel distances compared with other colobines. Minimum range size in 1 year at Wuyapiya is 16.25 km(2), although there is no asymptote for range size as a function of observation time. Range size for the Wuyapiya band is 25.25 km(2) over the 2-year study and appeared to cover 100 km(2) between 1985 and 1994. The primary food of R. bieti at Wuyapiya is lichens, which are ubiquitous in fir frees. The multitiered social organization of R. bieti appears to result from the interaction of food resource characters with the forces of mate competition, with band sizes based on female responses to the spatial and temporal characteristics of lichens and subdivisions within bands based on male competition for mates.
Resumo:
The vertical growth of seagrasses in response to burial by migration of bedforms is combined with dating techniques to provide precise and rapid estimates of the migration speed of subaqueous dunes over seagrass patches. Two methods to estimate the time interval between the passage of successive dunes and the motion of single dunes through seagrass patches are described. The second method is more precise. The application of these methods to vegetated (Cymodocea nodosa) subaqueous dunes in the Alfacs Bay (NW Mediterranean) showed that the dunes traveled at an average speed of $13.0 \pm 0.6 m yr^-1$ and demonstrated that the methods can resolve migration speeds from 0.15 to $980 m yr^-1$ with this particular seagrass species. In areas vegetated with different seagrass species, bedform migration can be estimated over different time scales. The strong coupling between seagrass and sediment dynamics resembles the coupling of vegetation and land dunes.
Resumo:
A gene, pfa1, encoding an autotransporter was cloned from a pathogenic Pseudomonas fluorescens strain, TSS, isolated from diseased fish. The expression of pfa1 is enhanced during infection and is regulated by growth phase and growth conditions. Mutation of pfa1 significantly attenuates the overall bacterial virulence of TSS and impairs the abilities of TSS in biofilm production, interaction with host cells, modulation of host immune responses, and dissemination in host blood. The putative protein encoded by pfa1 is 1,242 amino acids in length and characterized by the presence of three functional domains that are typical for autotransporters. The passenger domain of PfaI contains a putative serine protease (Pap) that exhibits apparent proteolytic activity when expressed in and purified from Escherichia coli as a recombinant protein. Consistent with the important role played by PfaI in bacterial virulence, purified recombinant Pap has a profound cytotoxic effect on cultured fish cells. Enzymatic analysis showed that recombinant Pap is relatively heat stable and has an optimal temperature and pH of 50 degrees C and pH 8.0. The domains of PfaI that are essential to autotransporting activity were localized, and on the basis of this, a PfaI-based autodisplay system (named AT1) was engineered to facilitate the insertion and transport of heterologous proteins. When expressed in E. coli, AT1 was able to deliver an integrated Edwardsiella tarda immunogen (Et18) onto the surface of bacterial cells. Compared to purified recombinant Et18, Et18 displayed by E. coli via AT1 induced significantly enhanced immunoprotection.
Resumo:
海波破碎过程研究的发展的分析出发,我们将把本文的工作重点放在(1)从 1988 年袁业立的改进了的破碎波统计模型出发(见第三节)导出海波破碎前后的海波谱之间的关系。(2)在一个破碎事件是在一个平均波峰间周期内完成的假定下导出波能耗散源函数的新的解析表达式,并将其用于 LGFD-II 型海浪数值预报模式,后者基本上是一个我们自己研制的第三代波浪数值模式(见第四节)。(3)从饱和谱型是由能量输入源函数,非线性能量转移源函数和能量耗散源函数综合平衡所导致的这一个观点出发,利用 Miles 输入源函数表达式,Hasselman 的非线性能量转移源函数表达式以及我们新导出的能量耗散函数表达式,导出饱和谱型(见第五节)。
Resumo:
The proposed plan for enrichment of the Sulu Sea, Philippines, a region of rich marine biodiversity, with thousands of tonnes of urea in order to stimulate algal blooms and sequester carbon is flawed for multiple reasons. Urea is preferentially used as a nitrogen source by some cyanobacteria and dinoflagellates, many of which are neutrally or positively buoyant. Biological pumps to the deep sea are classically leaky, and the inefficient burial of new biomass makes the estimation of a net loss of carbon from the atmosphere questionable at best. The potential for growth of toxic dinoflagellates is also high, as many grow well on urea and some even increase their toxicity when grown on urea. Many toxic dinoflagellates form cysts which can settle to the sediment and germinate in subsequent years, forming new blooms even without further fertilization. If large-scale blooms do occur, it is likely that they will contribute to hypoxia in the bottom waters upon decomposition. Lastly, urea production requires fossil fuel usage, further limiting the potential for net carbon sequestration. The environmental and economic impacts are potentially great and need to be rigorously assessed. (C) 2008 Elsevier Ltd. All rights reserved.