A new technique of physical dissipation and its application to a mesoscale numerical weather prediction model

In terms of statistical physics, a fluid such as the atmosphere is a many-body system which has a vast amount of degree of freedom and thus obeys the second law of thermodynamics. In this paper, a noticeable improvement of the prognostic outputs is made by reconstructing the terms of the horizontal diffusion of MM5 according to the principles of the second law of thermodynamics; besides, the computational noise is effectively and significantly suppressed since the physical dissipative technique for reconstructing suggested in this paper is based on the physical law rather than on the computational method such as the artificial viscosity.     

土地执法难的原因分析及对策初探

“合理利用土地,切实保护耕地”是我国的一项基本国策,而加强土地执法特别是解决执法难的问题是维护这项基本国策的重要保障。不可否认,土地执法难的问题在土地行政执法实践中普遍存在。其原因是多方面的,需要不断思考,提出解决问题的对策．     

Glacial outlet valley size–ice drainage area relationships: some considerations

Previous work indicates that large variations in the power‐law relationship, relating glacial outlet valley size to ice drainage area, may occur between different glaciological settings. In this paper, we take issue with methods used to quantify the relationships of outlet valley size to drainage area size and propose a general method for comparing power‐law relationships between study areas, to determine whether or not such power‐law scalings are similar. Based on this method, we demonstrate that outlet valleys have a similar sensitivity to variation in ice‐contributing area irrespective of their glaciological setting, contrary to earlier findings. Minor variation in such relationships may reflect the different lithological and glaciological settings of the study sites and provide an insight into the physics of glacial erosional development of landscapes. Despite their limitations, we conclude that power‐law relationships are valid and, when interpreted carefully, provide a useful basis for comparing the efficiency of glacial erosion processes in different locations. Copyright © 2003 John Wiley & Sons, Ltd.     

伸展盆地地表热流值的模拟计算—以渤海湾盆地济阳坳陷为例

伸展盆地的大地热流值可以认为是由地幔热流，地壳内部和盆地沉积物生热效应以及岩石圈和沉积物导热性质等多个因素综合叠加的结果。本文根据传热学理论，分析了纯剪切模式条件下伸展盆地内的地表热流值贡献的分布规律及其与伸展因子的理想关系，认为深部热源的能量，伸展因子大小，地壳浅层的生热性质以及盆地构造位置是控制盆地热流高低和展布的关键因素。结合沉积地层的导热性质，放射性元素的生热效应，岩浆区的现今地表热流分布，得到了与正演模拟相接近的结果，验证了该方法思路的有效性。同时对该地区幕式伸展裂陷过程中的地表热流值变化趋势进行了模拟，认为在不同的伸展裂陷幕地表热流值表现为阶段式的升高，在末期达到最大值。     

新集二矿11—2煤层沉积特征及对采掘的影响

通过对11—2煤层沉积赋存特征、夹矸岩性厚度变化特征、沉积基底及古流水冲蚀破坏作用的研究，讨论了11—2煤层沉积环境及其变化规律，总结了影响采掘的主要地质因素，并据此提出了矿井采掘中相应的管理方法和治理措施，对矿井生产具有一定的指导意义。     

基岩裂隙水运移模型评价

结合近几年的研究成果，按照建立模型时的能量方程不同，将基岩裂隙水运移模型划分为以Darcy定律为基础的模型和以Chezy公式为基础的模型；按照介质概化条件的差异，进一步划分为孔隙介质、裂隙介质和双重介质数学模型，并评价了各种模型的原理、适用条件及其优缺点。     

Aftershocks hazard in Italy Part I: Estimation of time-magnitude distribution model parameters and computation of probabilities of occurrence

We analyzed the available instrumental data on Italian earthquakes from1960 to 1996 to compute the parameters of the time-magnitudedistribution model proposed by Reasenberg and Jones (1989) andcurrently used to make aftershock forecasting in California. From 1981 to1996 we used the recently released Catalogo Strumentale deiTerremoti `Italiani' (CSTI) (Instrumental Catalog Working Group, 2001)joining the data of the Istituto Nazionale di Geofisica e Vulcanologia(INGV) and of the Italian major local seismic network, with magnituderevalued according to Gasperini (2001). From 1960 to 1980 we usedinstead the Progetto Finalizzato Geodinamica (PFG) catalog(Postpischl, 1985) with magnitude corrected to be homogeneous with thefollowing period. About 40 sequences are detected using two differentalgorithms and the results of the modeling for the corresponding ones arecompared. The average values of distribution parameters (p= 0.93±0.21, Log₁₀(c) = –1.53±0.54, b = 0.96±0.18 and a = –1.66±0.72) are in fair agreementwith similar computations performed in other regions of the World. We alsoanalyzed the spatial variation of model parameters that can be used topredict the sequence behavior in the first days of future Italian seismic crisis,before a reliable modeling of the ongoing sequence is available. Moreoversome nomograms to expeditiously estimate probabilities and rates ofaftershock in Italy are also computed.     

工业化与服务业化耦合规律在中国城市中的偏离及原因探讨

发达国家发展历程表明：随着工业化的不断深入，服务业无论产值或就业比例，都不断上升，遵循工业化与服务业化耦合的规律。但这一规律却在中国城市中发生偏离，即随着工业化的不断深入，服务业产值与就业比例总体呈下降趋势。产生这一偏离的原因在于：工业弱质化、产业结构转换不同步、人口规模过于庞大和国民财富空间大转移等，使得第三产业的大发展欠缺生产和消费的时空一致和门槛规模。因而中国的主要任务是大力扩充产业结构，实现产业结构同步转换，加速农村人口向城市集中，为带动第三产业和加速城市化进程创造前提条件。     

Finite element modelling of frictional instability between deformable rocks

Earthquakes are recognized as resulting from a stick–slip frictional instability along faults. Based on the node‐to‐point contact element strategy (an arbitrarily shaped contact element strategy applied with the static‐explicit algorithm for modelling non‐linear frictional contact problems proposed by authors), a finite element code for modelling the 3‐D non‐linear friction contact between deformable bodies has been developed and extended here to analyse the non‐linear stick–slip frictional instability between deformable rocks with a rate‐ and state‐dependent friction law. A typical fault bend model is taken as an application example to be analysed here. The variations of the normal contact force, the frictional force, the transition of stick–slip instable state and the related relative slip velocity along the fault between the deformable rocks and the stress evolution in the total bodies during the different stages are investigated, respectively. The calculated results demonstrate the usefulness of this code for simulating the non‐linear frictional instability between deformable rocks. Copyright © 2003 John Wiley & Sons, Ltd.