Beziehungen zwischen Gesteinsdeformation und Schallgeschwindigkeiten     

Professor Dr. Werner Plessmann  Prof. Dr.-Ing. Gerhard Spaeth 《International Journal of Earth Sciences》1972,61(3):1010-1019

Zusammenfassung Im Rheinischen Schiefergebirge verlaufen die höchsten Schallgeschwindigkeiten normalerweise parallel b. Taucht bei starker Verformung eine Faser in Richtung a auf, liegen die schnellsten Schallimpulse in a. Die Anordnung der Phyllosilikate ist Ursache dieser Anisotropie.

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In the Rheinisches Schiefergebirge the seismic velocities in most cases are parallel b. In regions with a strong deformation and a linear element in a, the highest velocities correspond with the same direction. This anisotropy is caused by the position of the phyllosilicates.

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Résumé Dans le Massif schisteux rhénan, les ondes sonores ont normalement leur plus grande vitesse de propagation dans la direction parallèle à « b ». Dans les roches tectoniquement déformées et caractérisées par une linéation selon « a », la plus grande vitesse se retrouve dans cette direction. Cette anisotropie est causée par la disposition des phyllosilicates.

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Regional development and the disintegration of Czechoslovakia     

Petr Pavlínek  Asssistant Professor 《Geoforum》1995,26(4):351-372

The breakup of Czechoslovakia on 31 December 1992 resulted in the emergence of a newly independent Slovakia and Czech Republic. The split is often interpreted as the result of ethnic nationalism. In contrast, this paper attempts to assess the influence of regional inequalities and uneven economic development on the split. Pre-World War Two Czechoslovakia was unable to address large regional differences between the Czech lands and Slovakia. The economic policies pursued by the state socialist governments following 1948 were directed toward the elimination of these differences through rapid industrialization of Slovakia. The economic transformation in Czechoslovakia after the collapse of state socialism resulted in reemergence of uneven development between Slovakia and the Czech lands, which contributed to the disintegration of the country. The links between economic issues and politics are discussed, and the paper shows how the regional inequalities and economic issues were used to justify the necessity of Slovak and Czech independence.  相似文献   

Editorial     

Professor Christian M. Rogerson 《GeoJournal》1990,22(3):227-229

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Theoretical study of cross-valley wind circulation     

Professor Dr. Wen Tang 《Meteorology and Atmospheric Physics》1976,25(1):1-18

Summary An analytical model is developed to investigate the interaction between the large scale prevailing air flow and the thermally induced slope wind circulation. The Boussinesq approximation is assumed. The lower order successive approximation solutions are obtained in spectral representation for both typical daytime and night time cases. The results have produced interesting circulation features often observed in mountainous terrain.

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Theoretische Untersuchung der ein Tal überquerenden Windzirkulation

Zusammenfassung Es wird ein analytisches Modell zur Untersuchung der Wechselwirkung zwischen einer großräu mig vorherrschenden ein Tal überführenden Luftströmung und der thermisch ausgelösten Hangwindzirkulation entwickelt. Dabei wird die Approximation nach Boussinesq angewendet. Für typische Verhältnisse bei Tag und bei Nacht werden Näherungslösungen niedrigerer Ordnung in spektraler Darstellung erhalten. Die Ergebnisse haben interessante Zirkulationsformen aufgezeigt, die oft im gebirgigen Gelände beobachtet werden.

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With 8 Figures  相似文献   

Energy Performance Improvement of a Solar Still System Using Date and Olive Kernels: Experimental Study     

Abdeldjabar Brihmat  Hocine Mahcene  Djamel Bechki  Hamza Bouguettaia  Abderrahmane Khechekhouche  Slimane Boughali 《洁净——土壤、空气、水》2023,51(2):2200384

Currently, solar distillation systems are used to contribute to solving the fresh water supply deficiency problem in some desert and rural areas. The present outdoor experimental work aims to improve the energy performance of a solar still installed in a semi-arid region. Experiments are performed using three solar distillers (a reference system, a distiller with date kernels, and one with olive kernels). The integration effect of two kernel types date and olive with different concentrations in the range of 300–600 g kernels per 5 L on the hourly and cumulus water production, and thermal and exergy efficiencies are analyzed. The results show that, for the same kernel mass concentration, the system with olive kernel is more effective than that with date kernels; moreover, compared to the reference system, cumulus water production of these systems at a mass concentration of 500 g kernels per 5 L is higher by ≈226% and 176%, respectively. At a concentration of 500 g kernels per 5 L, the average daily thermal efficiency of the solar still with olive kernels and that with date kernels is 38.01% and 30.7%, respectively, and their daily average exergy efficiency is 8.4% and 3.1%, respectively.  相似文献   

Dynamic Plastic Response of Circular Plates Resting on Fluid with Finite Deformation     

Wang Gang  Li Zhen  Chen Tieyun Ph. D.  Marine Design  Research Institute of China  Shanghai Engineer  Marine Design  Research Institute of China  Shanghai Professor  Dept. of Naval Architecture  Ocean Engineering  Shanghai Jiao Tong University  Shanghai 《中国海洋工程》1998,(1)

This paper concerns the dynamic plastic response of a circular plate resting on fluid subjectedto a uniformly distributed rectangular load pulse with finite deformation.It is assumed that the fluid isincompressible and inviscous,and the plate is made of rigid-plastic material and simply supported along itsedge.By using the method of the Hankel integral transformation,the nonuniform fluid resistance is de-rived as the plate and the fluid is coupled.Finally,an analytic solution for a circular plate under a mediumload is obtained according to the equations of motion of the plate with finite deformation.  相似文献   

An Experimental Investigation on Wave Loading on a Platform Mat     

Miao Guoping  Yao Meiwang  Zhang Chengyi  Ji Chunqun Professor  School of Naval Architecture  Ocean Engineering  Shanghai Jiao Tong University  Shanghai Senior Engineer  School of Naval Architecture  Ocean Engineering  Shanghai Jiao Tong University  Shanghai Engineer  School of Naval Architecture  Ocean Engineering  Shanghai Jiao Tong University  Shanghai 《中国海洋工程》1998,(1)

Overall wave loading and local hydrodynamic pressure distributions on a platform mat in reg-ular waves for shallow waters are experimentally investigated in order to examine the severity of thenonlinear effects and shallow water effects.Wave focusing phenomenon is observed in the tests.The meas-ured results may also provide a comparison basis for the theoretical development to consider the nonlinearinteraction between waves and viscous flow by introducing viscosity into wave theories.  相似文献   

A Numerical Model for Typhoon Surges     

PAN Junning  WANG Hongchuan  YAO Guoquan Graduate Student  River  Harbour Department  Nanjing Hydraulic Research Institute  Nanjing  P. R. China.Engineer  River  Harbour Department  Nanjing Hydraulic Research Institute  Nanjing  P. R. China. Professor  River  Harbour Department  Nanjing Hydarulic Research Institute  Nanjing  P. R. China. 《中国海洋工程》1998,(2)

-In this paper a simple and efficient implicit finite-difference scheme is used for depth-averagedtwo-dimensional storm surge model.This finite-difference scheme is simpler and more efficient than the wi-dely-used ADI scheme.Accuracy analysis and stability analysis indicate that the scheme has two-order ac-curacy and is unconditionally stable when the grid size is constant.The present analysis results show thatthe scheme is of higher numerical accuracy than that introduced by Maa(1990).After tested by ideal mod-els,a calculation example of a real typhoon surge is carried out,the results of the numerical simulation co-incide well with the observed data and the accuracy is sufficient for engineering applications.  相似文献   

Nonlinear Capillary-Gravity Waves Produced by a Vertically Oscillating Plate     

Philip L.-F.LIU 《中国海洋工程》1998,(2)

The nonlinear capillary-gravity wave produced by a vertically oscillating plate,in which thecontact-angle model is considered,is studied by use of the Boundary Integral Equation Method(BIEM).The present numerical experiment shows that the code is robust and efficient for modeling the generationand propagation of capillary-gravity waves.It is found that the wave heights of stationary periodicnonlinear waves radiated away from the plate are dependent on the parameters involved in the contact-an-gle model.The effect of the contact-angle hysteresis and the nonlinearity of capillary-gravity waves on thewave profile is discussed in the paper.  相似文献