Catastrophe mechanism & classification of discontinuity behavior in thermal science (Ⅰ) --Fold catastrophe

The mechanism of discontinuity behavior has important significance in the study of thermal science,such as fire,combustion,explosion and heat transfer.This sort of discontinuity behavior and the catastrophe caused by system nonlinearity may be equivalently classified according to the catastrophe model promulgated by catastrophe theory.Under the conditions of uniform temperature and thermal isolation,the self-ignition behavior of a Semenov System can be viewed as a result of the fold catastrophe of the system.     

Catastrophe mechanism and classification of discontinuity behavior in thermal science (Ⅱ) -- Cusp catastrophe

The catastrophe mechanisms of thermal performance characteristics of the firebox gas combustion system were analyzed from the viewpoint of catastrophe theory. The mathematical models of cusp catastrophe were established. The relationship between the thermal performance characteristics and the changing of system control variables was studied. The cusp catastrophe mechanisms of typical performance characteristics, such as kicking and lagging, and those of transition from quenching to igniting were explained. It was illustrated that discontinuity behavior of thermal systems with an "S" motion feature curve and lagging feature may be equivalently classified according to the topology of cusp catastrophe, influenced by two groups of independent control variables.     

Catastrophe mechanism and classification of discontinuity behavior in thermal science (II)

The catastrophe mechanisms of thermal performance characteristics of the firebox gas combustion system were analyzed from the viewpoint of catastrophe theory. The mathematical models of cusp catastrophe were established. The relationship between the thermal performance characteristics and the changing of system control variables was studied. The cusp catastrophe mechanisms of typical performance characteristics, such as kicking and lagging, and those of transition from quenching to igniting were explained. It was illustrated that discontinuity behavior of thermal systems with an “S” motion feature curve and lagging feature may be equivalently classified according to the topology of cusp catastrophe, influenced by two groups of independent control variables.     

基于突变论的储层边界尖点突变技术及应用研究

基于油气储层异常体及其边界处的突变特征提出了油气储层边界尖点突变技术.这种技术是将地震时间序列x(t)化为突变论中的尖点突变模型的标准形式v(x),进而可得出平衡曲面方程和分叉集方程,在此基础上,可求得突变参数,用以有效而准确地确定油气储层异常体的空间分布范围及其边界.     

A model of backdraft phenomenon in building fires

In order to further investigate the physical mechanism of the backdraft phenomenon in building fires, a simplified mathematical model is established based on energy balance equation, and its catastrophe mechanism is analyzed based on catastrophe theory, and the relationship between system control variables and fire conditions is studied. It is indicated that the backdraft phenomenon is a kind of typical catastrophe behavior, and of the common characteristics of catastrophe.     

突变理论在企业管理中的应用探讨

本文对突变理论在企业管理中的应用可能性进行了探讨,文中运用尖点突变模型,对企业中的行为科学领域、组织结构与发展管理领域及管理决策领域进行了应用分析。并指出了突变理论在这些领域的应用前景、存在问题和发展方向。     

转子系统故障发展过程的突变

介绍了突变故障的几何描述与突变特征,分析了机械系统故障发生的机理,采用非线性理论与突变理论,对突变故障和系统振动状态突变进行了数学描述·建立了分岔集方程,由分岔集方程得出了振幅产生突变的临界值,当激励幅值越过该临界值时,会导致振动状态突变,而诱发机械系统的突发性故障,故其临界值可用来诊断与预测机械系统的突变现象,以便采取有效措施来限制故障的发生和发展·     

治安系统中的分歧现象——非平衡系统理论应用(Ⅱ)

将非平衡系统理论应用于治安问题的研究,建立了治安系统的非线性模型,用定性与定量结合的方法,从微观及宏观对系统的定态和动态进行了分析,由此可得一些对治安问题的进一步认识和启示。     

尖点突变模型在FRP约束混凝土柱变形中的应用

为进一步研究FRP(纤维增强复合材料)约束混凝土受压构件的变形性能以及对其有影响的参数,利用突变理论的特性和优点,对长期荷载作用下FRP约束混凝土受压构件的轴压比与其徐变终值的关系进行分析论证,建立了一个考虑徐变终值(S)、轴压比(N)和构件性质(R)的尖点突变模型,通过已有试验数据确定参数α,β,γ的值以及轴压比系数k.根据现有试验数据计算所得的F值与理论值比较接近.计算结果表明以尖点突变模型拟合S-N-R之间的关系与实际吻合良好,证明了此尖点突变模型的准确性较高.     

论我国巨灾保险立法的历程、现状与改进

梳理了我国保险立法的演进过程,评析政府和学术界所作的理论研究和改进,提出我国巨灾保险立法时机已成熟,未来的巨灾保险立法体系应有专门的巨灾保险法律,辅之以多项巨灾保险法规。巨灾保险立法应体现巨灾保险的强制性。     

Low-velocity zone atop the 410-km seismic discontinuity in the northwestern United States

The seismic discontinuity at 410 km depth in the Earth's mantle is generally attributed to the phase transition of (Mg,Fe)2SiO4 (refs 1, 2) from the olivine to wadsleyite structure. Variation in the depth of this discontinuity is often taken as a proxy for mantle temperature owing to its response to thermal perturbations. For example, a cold anomaly would elevate the 410-km discontinuity, because of its positive Clapeyron slope, whereas a warm anomaly would depress the discontinuity. But trade-offs between seismic wave-speed heterogeneity and discontinuity topography often inhibit detailed analysis of these discontinuities, and structure often appears very complicated. Here we simultaneously model seismic refracted waves and scattered waves from the 410-km discontinuity in the western United States to constrain structure in the region. We find a low-velocity zone, with a shear-wave velocity drop of 5%, on top of the 410-km discontinuity beneath the northwestern United States, extending from southwestern Oregon to the northern Basin and Range province. This low-velocity zone has a thickness that varies from 20 to 90 km with rapid lateral variations. Its spatial extent coincides with both an anomalous composition of overlying volcanism and seismic 'receiver-function' observations observed above the region. We interpret the low-velocity zone as a compositional anomaly, possibly due to a dense partial-melt layer, which may be linked to prior subduction of the Farallon plate and back-arc extension. The existence of such a layer could be indicative of high water content in the Earth's transition zone.     

突变理论在零售商综合竞争力评价中的应用研究

将突变理论应用于零售企业综合竞争力评价过程,主要是以突变理论的基本原理为理论基础,结合零售企业的经营特点建立符合零售业的竞争力指标体系并对其进行综合评价。研究列举了两种突变理论在零售企业综合竞争力的应用情形,研究结果表明突变理论减少了传统方法主观评价所引起的误差影响,适合于企业竞争力比较评价     

一类混沌系统动力学行为的突变分析

通过对一类混沌系统突变行为的分析发现,在其突变区域,系统可出现2个由稳定不动点决定的混沌吸引子.随着系统参数的变化,当某个吸引子的吸引域逾越不稳定不动点界限或临界状态时,系统将突变到另一吸引子上,并且在系统参数变化范围相同的区域,若系统参数变化的趋势不同,系统的动力学行为不同.在突变区域,通过适当选取系统的初始值,可改变系统的动力学行为走向.     

基于突变级数法的建筑设计方案优选

在相关研究基础上,基于突变理论,建立了建筑设计方案综合评价和优选的突变级数法.首先对建筑设计方案的评价目标进行多层次分解,从使用功能、技术性能、经济指标和环境效果等四个方面,建立建筑设计方案综合评价和优选的递阶指标体系,然后对评价指标属性值数据进行归一化处理,根据相应的突变系统数学模型计算突变模糊隶属函数值,最后计算评价目标的总突变级数值,据此对建筑设计方案进行评价和优选.实例研究表明,该方法可靠性高、客观性强,为工程实践中建筑设计方案评价和优选提供了新思路和途径.     

基于突变理论的开拓方式优选

 鉴于常规多指标决策法在处理开拓方案优选问题时存在不足,建立了基于突变理论的开拓方案优选系统。以新桥矿露天转地下开拓方案为例建立评价模型;综合考虑决策开拓方案的影响指标,如经济、技术、地质、通风与环保条件等;对各评价指标依重要性进行整合处理,构建层状评价系统;应用归一公式对评价系统进行递归运算,计算各方案最终突变隶属函数值,得到3个方案的评价值分别为0.960、0.976和0.953,从而确定方案Ⅱ最优。     

传热场问题的界面元法

用界面元法求解场问题,导出了求解三维不稳定温度场的界面元计算公式,这些公式适用于连续及不连续温度场,能反映介质可能存在的温度不连续性,较以往数值方法具有精度高、基本未知量少、适用于任意形状单元的优点,为温度场与位移场、应力场的耦合奠定了基础。     

Topographies of seismic velocity discontinuities and penetrations of subducting slabs beneath the Sea of Okhotsk

The existence of discontinuities, the topographies of the 410 km and 660 km discontinuities, and the penetrations of subducting slabs near the 660 km discontinuities beneath the Sea of Okhotsk were studied using Nth root slant stack and digital records from networks in Germany and the western United States. Results show the obvious evidence for reflected and refractive phases associated with the 410 km and 660 km discontinuities. There may be discontinuities at other depths such as 150 km, 220 km and 520 km. The 410 km discontinuity is elevated and the 660 km discontinuity is depressed respectively, consistent with the expected thermal signature of the phase transitions. The subducting slab has penetrated into the lower mantle in the northern part of the Sea of Okhotsk, while it is stagnant on the 660 km discontinuity in the southern part.     

气候层次理论及其应用(Ⅱ)——气候突变

本文首先用超熵产生作为判据,讨论了北半球气温的突变情况。其结果,与记录相符.而后,在气候层次理论和非线性动力理论的基础上,我们提出了气候突变的三种机制;跃迁突变、“贯穿”突变和转换突变。     

太阳风起源区等离子体动力学机制

 根据太阳风的起源,对太阳风的等离子体动力学理论进行研究。对磁流体力学（MHD）做了详细概述,在此基础上讨论稳定态下的震波结构,并进行详细的公式推导,特别是对它的不连续结构与旋转不连续的性质进行说明。通过对卫星观测结果的分析,得到两种磁场方向不连续面：切向不连续（TD）和旋转不连续（RD）。研究表明,TD的特性为垂直不连续面的磁场分量为零,电离子不通过该面;RD两侧的磁场方向不同但是大小相同,且有电离子通过该不连续面。太阳风中旋转不连续面主要与高速太阳风有关。通过分析6种不连续结构得到：在通过界面的磁通量保持不变的情况下,切向磁场会任意改变方向,出现旋转不连续现象,且此现象能够通过一维空间结构图方法加以验证。通过对比推导结果与数据验证图,发现数据图的分析支持公式的推导,证实太阳风起源区等离子存在旋转不连续机制。     

管状非绝热反应中的燕尾型突变

考虑管状非绝热反应的轴向弥散定常问题，提出了求解相应于燕尾型突变的四阶折叠点的正则扩张系统，最后用一个有效的算法找到了管状非绝热反应问题中的燕尾型突变点。