浅谈城市发展与防震减灾

通过对加强防震减灾规划,加强地震安全性评价工作,加强地震应急救援能力以及增强公众防震减灾意识等4个方面的分析,揭示了城市发展与防震减灾的关系,强调了建设地震安全社区的重要性。     

新疆防震减灾科普教育基地正式向社会开放

为了不断推进我区防震减灾科普宣传教育工作,努力提高社会民众应对地震灾害事件的心理承受能力和防震减灾意识,新疆维吾尔自治区地震局完成了我区首个防震减灾科普教育基地的建设工作。防震减灾科普教育基地由防震减灾科普馆、乌鲁木齐水磨沟地震台和地震活断层剖面三部分组成。其中,防震减灾科普馆由防震减灾知识图片区、影视区、模拟震动区、地震观测仪器陈列区、自救互救知识区和新疆主要地震构造及地震震中分布沙盘六部分组成。     

汶川地震对江苏省盐城市防震减灾工作的几点启示

通过分析汶川地震后应急工作中存在的一些问题,结合盐城市防震减灾工作的实际,从加强盐城市县级地震机构和能力建设、健全和完善地震应急预案体系、加强抗震设防工作、加强监测台站建设、全面开展防震减灾知识宣传教育、加强地震应急救援建设等6个方面提出了今后做好本地区防震减灾工作的建议和措施。     

关于加强海东地区防震减灾工作的思考

0 前言 海东地区地处祁连山、大板山、拉脊山等地震断裂带之间，是全国21个地震重点监视防御区之一，防震减灾的任务十分艰巨。加强防震减灾工作，对于全区经济社会发展，构建和谐海东至关重要，因此，必须进一步提高对防震减灾工作的重要性和必要性的认识，理清思路，落实措施，努力提高防震减灾工作水平。     

推进防震减灾工作构建地震安全新太原

吸取汶川地震教训,结合太原市防震减灾工作的实践经验,提出要使防震减灾工作又好又快地发展,必须做好“三个主体、三种关系、三项结合、三个促进”等几方面的工作,以构建地震安全新太原。     

地震重点监视防御区制度实施现状调查(山东市级)

以山东省市级防震减灾工作为研究对象,在全国范围内组织开展了两次(2007年、2012年)地震重点监视防御区制度实施情况问卷调查,根据回收的问卷从市级防震减灾组织机构、经费投入、监测预报、震害防御、应急救援和宣传教育等6个方面14项指标人手,对比地震重点监视防御区和非地震重点监视防御区防震减灾工作在两个调查年度的发展、变化,分析研究地震重点监视防御区制度在山东省(市级)的实施现状和成效.将两个调查年度描述山东省防震减灾工作进展的主要指标与全国相应指标的均值进行了对比研究.并对防震减灾工作的“山东现象”进行了分析.     

四川省防震减灾素质教育工程设计

四川省防震减灾素质教育工程的建设内容包括1个防震减灾素质教育中心、39个防震减灾科普宣传服务站、180个防震减灾科普示范学校和25个防震减灾科普示范社区。教育工程能够实现全省防震减灾科普知识的有效宣传,以及地震信息的实时发布和地震救援信息的实时更新。     

浅谈基层地震工作机构的现状与思考

防震减灾是一项关系国计民生的重要工作，健全和完善地震工作机构是加强防震减灾工作中的一项必要措施。基层地震工作机构是否能够正常开展工作，直接影响防震减灾工作的顺利进行。从近几年的实际情况看，基层地震工作机构的现状还远远不能满足工作需要。     

地震标准化进展综述(之二)

4　“十五”地震标准化工作设想与发展 地震标准化的实质是它的技术性 ,主要是立足于防震减灾体系中的技术指标。地震标准作为一种技术性规范文件 ,是根据我国防震减灾规划和地震科学技术发展需要 ,按照规定的程序 ,对地震科技成果和实践的先进经验进行总结制定出来的。因此 ,地震标准化一定要以建立防震减灾工作的最佳工作秩序和提高地震科学技术水平为最终目的。为了达到这一目的 ,除了依据《中华人民共和国防震减灾法》来调整防震减灾领域中各个方面的关系外 ,就是要依据一整套行之有效的、科学合理的地震技术法规对地震行业存在共同的、…     

安徽省中等城市地震应急信息管理系统研究

中等城市地震应急系统建设是地市级地震部门防震减灾工作的重要组成部分,本文通过对安徽省6个中等城市防震减灾应急信息系统建设的经验总结,介绍了系统设计与实现的思路,对重点技术和功能进行了论述。     

宇宙分维构造及其数学基础

探讨了宇宙分维构造的形式,给出了分维微积分及分形测度的数学基础,包括分维导数及分维微积分的表述形式、分维微分方程的规整空间积分解、分形测度的分维微积分定义及自相似分形的测度计算方程．作为诠释,探讨了原子核内中子与质子的趋势关系方程,以及其周期解和原子序数极限值。     

Is fractal dispersion subdiffusive or superdiffusive? A theoretical investigation

A probabilistic approach is used to simulate particle tracking along a fractal path. The particle tracking is modelled as the sum of elementary steps with independent random variables. An exponential distribution is obtained for each elementary step and a Gamma distribution or probability density function is then deduced. The relationship between fractal dispersivity and the elementary step is given. It is theoretically demonstrated that the fractal dispersion is subdiffusive and that the linear dispersion coefficient and the linear dispersivity decrease with the mean travel distance. A review of some fractal models showing an increase of the linear dispersivity is given and an explanation that shows why these models may be not correct is proposed. It is shown that the results presented are in agreement with other studies relating to the application of the fractional calculus to diffusion transport. Lastly, a relation between the fractal dimension and the order of the fractional Langevin equation is proposed. Copyright © 2007 John Wiley & Sons, Ltd.     

Application of Hausdorff fractal derivative to the determination of the vertical sediment concentration distribution

The Rouse formula and its variants have been widely used to calculate the steady-state vertical concentration distribution for suspended sediment in steady sediment-laden flows, where the diffusive flux is assumed to be Fickian. Turbulent flow, however, exhibits fractal properties, leading to non-Fickian diffusive flux for sediment particles. To characterize non-Fickian dynamics of suspended sediment, the current study proposes a Hausdorff fractal derivative based advection-dispersion equation(H...     

Turbulent diffusion in linear shear flow

Summary An analysis of the characteristics of the eddy diffusivity is made, and the equation for turbulent diffusion in a linear flow is derived. This diffusion equation is solved analytically.     

Implication of the flow resistance formulae on the prediction of flood wave propagation

ABSTRACT

This study examines the difference in the predictions of flood wave propagation in open channels depending on the flow resistance formulae, such as the Chézy and Manning’s equation. The celerity and diffusion coefficient are functions of the channel geometry, slope, roughness as well as the resistance formulae. The results suggest that substituting the Chézy equation with Manning’s equation results in different characteristics of flood propagation, which are consistent regardless of the cross-sectional geometry except for a circular cross-section: increasing celerity and decreasing diffusion coefficient. The celerity is more sensitive to the selection of resistance formulae than the diffusion coefficient. Geometry has a greater effect on the celerity and diffusion coefficient, and consequently on the resulting hydrographs. Manning’s equation results in a larger difference in celerity and diffusion coefficient compared to Chézy equation regardless of the water depth. Overall, this study shows that the selection of resistance formulae is important in terms of the resulting hydrographs and peak flow.

EDITOR Z.W. Kundzewicz ASSOCIATE EDITOR not assigned     

Solution of the transport equations using a moving coordinate system

A convection-diffusion equation arises from the conservation equations in miscible and immiscible flooding, thermal recovery, and water movement through desiccated soil. When the convection term dominates the diffusion term, the equations are very difficult to solve numerically. Owing to the hyperbolic character assumed for dominating convection, inaccurate, oscillating solutions result. A new solution technique minimizes the oscillations. The differential equation is transformed into a moving coordinate system which eliminates the convection term but makes the boundary location change in time. We illustrate the new method on two one-dimensional problems: the linear convection-diffusion equation and a non-linear diffusion type equation governing water movement through desiccated soil. Transforming the linear convection diffusion equation into a moving coordinate system gives a diffusion equation with time dependent boundary conditions. We apply orthogonal collocation on finite elements with a Crank-Nicholson time discretization. Comparisons are made to schemes using fixed coordinate systems. The equation describing movement of water in dry soil is a highly non-linear diffusion-type equation with coefficients varying over six orders of magnitude. We solve the equation in a coordinate system moving with a time-dependent velocity, which is determined by the location of the largest gradient of the solution. The finite difference technique with a variable grid size is applied, and a modified Crank-Nicholson technique is used for the temporal discretization. Comparisons are made to an exact solution obtained by similarity transformation, and with an ordinary finite difference scheme on a fixed coordinate system.     

A Boltzmann-based mesoscopic model for contaminant transport in flow systems

The objective of this paper is to demonstrate the formulation of a numerical model for mass transport based on the Bhatnagar–Gross–Krook (BGK) Boltzmann equation. To this end, the classical chemical transport equation is derived as the zeroth moment of the BGK Boltzmann differential equation. The relationship between the mass transport equation and the BGK Boltzmann equation allows an alternative approach to numerical modeling of mass transport, wherein mass fluxes are formulated indirectly from the zeroth moment of a difference model for the BGK Boltzmann equation rather than directly from the transport equation. In particular, a second-order numerical solution for the transport equation based on the discrete BGK Boltzmann equation is developed. The numerical discretization of the first-order BGK Boltzmann differential equation is straightforward and leads to diffusion effects being accounted for algebraically rather than through a second-order Fickian term. The resultant model satisfies the entropy condition, thus preventing the emergence of non-physically realizable solutions including oscillations in the vicinity of the front. Integration of the BGK Boltzmann difference equation into the particle velocity space provides the mass fluxes from the control volume and thus the difference equation for mass concentration. The difference model is a local approximation and thus may be easily included in a parallel model or in accounting for complex geometry. Numerical tests for a range of advection–diffusion transport problems, including one- and two-dimensional pure advection transport and advection–diffusion transport show the accuracy of the proposed model in comparison to analytical solutions and solutions obtained by other schemes.     

On the using cumulant expansion method and van Kampen’s lemma for stochastic differential equations with forcing

Second-order exact ensemble averaged equation for linear stochastic differential equations with multiplicative randomness and random forcing is obtained by using the cumulant expansion ensemble averaging method and by taking the time dependent sure part of the multiplicative operator into account. It is shown that the satisfaction of the commutativity and the reversibility requirements proposed earlier for linear stochastic differential equations without forcing are necessary for the linear stochastic differential equations with forcing when the cumulant expansion ensemble averaging method is used. It is shown that the applicability of the operator equality, which is used for the separation of operators in the literature, is also subjected to the satisfaction of the commutativity and the reversibility requirements. The van Kampen’s lemma, which is proposed for the analysis of nonlinear stochastic differential equations, is modified in order to make the probability density function obtained through the lemma depend on the forcing terms too. The second-order exact ensemble averaged equation for linear stochastic differential equations with multiplicative randomness and random forcing is also obtained by using the modified van Kampen’s lemma in order to validate the correctness of the modified lemma. Second-order exact ensemble averaged equation for one dimensional convection diffusion equation with reaction and source is obtained by using the cumulant expansion ensemble averaging method. It is shown that the van Kampen’s lemma can yield the cumulant expansion ensemble averaging result for linear stochastic differential equations when the lemma is applied to the interaction representation of the governing differential equation. It is found that the ensemble averaged equations given for one the dimensional convection diffusion equation with reaction and source in the literature obtained by applying the lemma to the original differential equation are restricted with small sure part of multiplicative operator. Second-order exact differential equations for the evolution of the probability density function for the one dimensional convection diffusion equation with reaction and source and one dimensional nonlinear overland flow equation with source are obtained by using the modified van Kampen’s lemma. The equation for the evolution of the probability density function for one dimensional nonlinear overland flow equation with source given in the literature is found to be not second-order exact. It is found that the differential equations for the evolution of the probability density functions for various hydrological processes given in the literature are not second-order exact. The significance of the new terms found due to the second-order exact ensemble averaging performed on the one dimensional convection diffusion equation with reaction and source and during the application of the van Kampen’s lemma to the one dimensional nonlinear overland flow equation with source is investigated.