Analysis of Sustained Ground-Water Withdrawals by the Combined     

T. S. Chau 《Ground water》1988,26(4):454-463

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Broad-band observations of earthquake-induced rotational ground motions     

Heiner Igel  Alain Cochard  Joachim Wassermann  Asher Flaws †  Ulrich Schreiber  Alex Velikoseltsev  Nguyen Pham Dinh 《Geophysical Journal International》2007,168(1):182-196

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Evaluation of seismic ground motion induced by topographic irregularity   总被引：1，自引：0，他引：1  

Khoa-Van Nguyen  Behrouz Gatmiri   《Soil Dynamics and Earthquake Engineering》2007,27(2):183-188

Results of an extensive numerical study on the 2D scattering of seismic waves by local topography are presented. The investigation has been conducted using the direct boundary element method. Several types of topography (slopes, canyons and ridges) are considered. The influences of some key parameters, such as exciting frequency and geometry of the irregular feature, on surface ground motion are studied in detail. It is found that local topographic conditions play an important role in the modification of seismic ground motion at the irregular feature itself and its neighbourhood. The present results can be considered to be useful from the viewpoint of earthquake engineering and seismology.  相似文献   

Pounding of structures modelled as non‐linear impacts of two oscillators     

K. T. Chau  X. X. Wei 《地震工程与结构动力学》2001,30(5):633-651

A new formulation is proposed to model pounding between two adjacent structures, with natural periods T₁ and T₂ and damping ratios ζ₁ and ζ₂ under harmonic earthquake excitation, as non‐linear Hertzian impact between two single‐degree‐of‐freedom oscillators. For the case of rigid impacts, a special case of our analytical solution has been given by Davis (‘Pounding of buildings modelled by an impact oscillator’ Earthquake Engineering and Structural Dynamics, 1992; 21 :253–274) for an oscillator pounding on a stationary barrier. Our analytical predictions for rigid impacts agree qualitatively with our numerical simulations for non‐rigid impacts. When the difference in natural periods between the two oscillators increases, the impact velocity also increases drastically. The impact velocity spectrum is, however, relatively insensitive to the standoff distance. The maximum relative impact velocity of the coupled system can occur at an excitation period T_n^* which is either between those of the two oscillators or less than both of them, depending on the ratios T₁/T₂ and ζ₁/ζ₂. Although the pounding force between two oscillators has been primarily modelled by the Hertz contact law, parametric studies show that the maximum relative impact velocity is not very sensitive to changes in the contact parameters. Copyright © 2001 John Wiley & Sons, Ltd.  相似文献   

Probabilistic Seismic Hazard Assessment Along the Southeastern Coast of Vietnam     

Hong Phuong  Nguyen 《Natural Hazards》2001,24(1):53-74

On the basis of the analysis of geological, tectonic characteristics and earthquake manifestation features, a causative relation between geodynamic regime and seismicity has been established for the southeastern coastal zone and continental shelf of Vietnam. The probabilistic methods have been used to evaluate ground shaking effects at Nha Trang city aswell as for the entire study area. Short, intermediate and long term predictions of ground shaking (in the form of peak ground accelerationmaps) show high risks in the coastal zone of central Vietnam and in the southeastern continental shelf of the country.  相似文献   

Simulation of acid water movement in canals   总被引：1，自引：0，他引：1  

To Van Truong  Nguyen Tat Dac  Huynh Ngoc Phienc   《Journal of Hydrology》1996,180(1-4):361-371

An attempt to tackle the problem of the propagation of acid water in canals is described, and a mathematical model to simulate the acid water movement is developed, in which the jurbanite equilibrium is found to prevail. The processes of settling owing to sedimentation, precipitation and redissolution have been considered in the modelling. Data available from Tan Thanh, in the Plain of Reeds of the Mekong Delta in Viet Nam, are used as a case study.  相似文献   

Covariations in oceanic dimethyl sulfide,its oxidation products and rain acidity at Amsterdam Island in the Southern Indian Ocean   总被引：5，自引：0，他引：5  

B. C. Nguyen  N. Mihalopoulos  J. P. Putaud  A. Gaudry  L. Gallet  W. C. Keene  J. N. Galloway 《Journal of Atmospheric Chemistry》1992,15(1):39-53

Simultaneous measurements of rain acidity and dimethyl sulfide (DMS) at the ocean surface and in the atmosphere were performed at Amsterdam Island over a 4 year period. During the last 2 years, measurements of sulfur dioxide (SO₂) in the atmosphere and of methane sulfonic acid (MSA) and non-sea-salt-sulfate (nss-SO₄ ^2-) in rainwater were also performed. Covariations are observed between the oceanic and atmospheric DMS concentrations, atmospheric SO₂ concentrations, wet deposition of MSA, nss-SO₄ ^2-, and rain acidity. A comparable summer to winter ratio of DMS and SO₂ in the atmosphere and MSA in precipitation were also observed. From the chemical composition of precipitation we estimate that DMS oxidation products contribute approximately 40% of the rain acidity. If we consider the acidity in excess, then DMS oxidation products contribute about 55%.  相似文献   

Book reviews     

Mark S. T. Bukowinski  Philip E. Wannamaker  Manfred Koch  Yukio Fujinawa  Dr. Pradeep Talwani  D. Möhlmann  Andrew H. Knoll  Lucia Lovison-Golob  Krzysztof Haman  Hanna Pawłowska  Henryk Piwkowski  Dr. Anthony Dore  Nguyen Xuan Huy  Edward R. Cook  Jan Błecki  Jacek Leliwa-Kopystynski  Magdalena Sroczynska-Kozuchowska 《Pure and Applied Geophysics》1993,140(1):139-177

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Complexing capacity of the nutrient medium and its relation to inhibition of algal photosynthesis by copper     

Dr. René Gächter  Ken Lum-Shue-Chan  Y. K. Chau 《Aquatic Sciences - Research Across Boundaries》1973,35(2):252-261

The toxic effect of copper on phytoplankton production is investigated in waters having different complexing capacities. It is demonstrated that a water’s complexing capacity does not guarantee that an equivalent amount of copper could be tolerated without adversely affecting algal production. Possible explanations for these findings are offered and discussed. It is deduced that ionic copper probably is already toxic to planktonic algae at concentrations of about 10^?10 mole/l.  相似文献   

Adaptive neuro-fuzzy inference system coupled with shuffled frog leaping algorithm for predicting river streamflow time series     

Babak Mohammadi  Nguyen Thi Thuy Linh  Ali Najah Ahmed  Jana Vojteková  Yiqing Guan 《水文科学杂志》2020,65(10):1738-1751

ABSTRACT

Accurate runoff forecasting plays a key role in catchment water management and water resources system planning. To improve the prediction accuracy, one needs to strive to develop a reliable and accurate forecasting model for streamflow. In this study, the novel combination of the adaptive neuro-fuzzy inference system (ANFIS) model with the shuffled frog-leaping algorithm (SFLA) is proposed. Historical streamflow data of two different rivers were collected to examine the performance of the proposed model. To evaluate the performance of the proposed ANFIS-SFLA model, six different scenarios for the model input–output architecture were investigated. The results show that the proposed ANFIS-SFLA model (R² = 0.88; NS = 0.88; RMSE = 142.30 (m³/s); MAE = 88.94 (m³/s); MAPE = 35.19%) significantly improved the forecasting accuracy and outperformed the classic ANFIS model (R² = 0.83; NS = 0.83; RMSE = 167.81; MAE = 115.83 (m³/s); MAPE = 45.97%). The proposed model could be generalized and applied in different rivers worldwide.  相似文献