Matched field processing of deep-water ambient noise     

Sotirin  B.J. Tran  J.-M.Q.D. Hodgkiss  W.S.  Jr. 《Oceanic Engineering, IEEE Journal of》1990,15(4):316-323

Matched-field ambiguity surfaces produced by deep-water ambient-noise data are discussed and quantified in terms of power levels and correlation values. Two processors were implemented (Bartlett and minimum variance) using data at 35 and 95 Hz with similar but distinct vertical angular distributions. In general, the ambiguity surfaces have both diffuse and discrete components. The diffuse distribution extends across the sound channel with correlation values increasing with distance. The discrete sources have higher correlation values and are distributed in a convergence-zone sidelobe structure. Local wind conditions appear to affect the received power but not the correlation values or the processor output power  相似文献   

Simulated annealing technique in discrete fracture network inversion: optimizing the optimization     

Nam H. Tran 《Computational Geosciences》2007,11(3):249-260

Simulated annealing (SA) has the capacity to handle complex problem of fracture heterogeneity. However, its applications to characterization and modeling of an actual discrete fracture network are limited. Borrowing the context of geothermal reservoirs (where extensive discrete fractures exist), this paper attempts to solve several key practical issues that persist in current models: objective function’s (OF’s) formulation, modification scheme, and stop criteria. The improvements are examined in a case study on an actual fracture outcrop, where results are compared with a current and advanced SA work.  相似文献   

Rainfall-induced catastrophic landslide in Quang Tri Province: the deadliest single landslide event in Vietnam in 2020     

Van Tien  Pham  Luong  Le Hong  Duc  Do Minh  Trinh  Phan Trong  Quynh  Dinh Thi  Lan  Nguyen Chau  Thuy  Dang Thi  Phi  Nguyen Quoc  Cuong  Tran Quoc  Dang  Khang  Loi  Doan Huy 《Landslides》2021,18(6):2323-2327

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Description of a complex,rainfall-induced landslide within a multi-stage three-dimensional model     

Tran  T. V.  Alvioli  M.  Hoang  V. H. 《Natural Hazards》2022,110(3):1953-1968

Natural Hazards - The mechanical processes involved in movements of earth or rock masses under the effect of gravity—a landslide—may include several phases where the failure of one...  相似文献   

Performances of Different Machine Learning Algorithms for Predicting Saltwater Intrusion in the Vietnamese Mekong Delta Using Limited Input Data: A Study from Ham Luong River     

Tran  T. T.  Pham  N. H.  Pham  Q. B.  Pham  T. L.  Ngo  X. Q.  Nguyen  D. L.  Nguyen  P. N.  Veettil  B. K. 《Water Resources》2022,49(3):391-401

Water Resources - Accurate forecasting of salinity intrusion has a vital role in water resource management to mitigate and prevent its adverse effects. However, monitoring of salinity presents...  相似文献   

A Closed-Form Solution for Tunnels with Arbitrary Cross Section Excavated in Elastic Anisotropic Ground   总被引：1，自引：1，他引：0  

Huy Tran Manh  Jean Sulem  Didier Subrin 《Rock Mechanics and Rock Engineering》2015,48(1):277-288

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Generation of a North/South Magnetic Field Component from Variations in the Photospheric Magnetic Field     

Roger K. Ulrich  Tham Tran 《Solar physics》2016,291(4):1059-1076

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Origin of the Permian-Triassic komatiites,northwestern Vietnam   总被引：7，自引：0，他引：7  

Eero?HanskiEmail author  Richard?J.?Walker  Hannu?Huhma  Gleb?V.?Polyakov  Pavel?A.?Balykin  Tran Trong Hoa  Ngo Thi Phuong 《Contributions to Mineralogy and Petrology》2004,147(4):453-469

Abstract Rare examples of Phanerozoic komatiites are found in the Song Da zone, NW Vietnam. These komatiites were erupted through continental crust and may belong to the SE extension of the Permo-Triassic Emeishan volcanic province located in SW China. They provide a good opportunity to study the source characteristics of starting plume magmas in a continental flood basalt province. Erupted on late-Permian carbonate rocks, the komatiitic rocks are interbedded with low-Ti olivine basalts. Basaltic komatiites display pyroxene spinifex textures, while more magnesian rocks (MgO up to 32 wt.%) are porphyritic, containing a single, cognate population of euhedral to elongated olivine phenocrysts with Fo up to 93.0%. This suggests a highly magnesian parental magma with 22–23 wt.% MgO. In terms of major and minor elements, the komatiites are similar to the ca. 89 Ma old Gorgona Island komatiites of Colombia. The Song Da komatiites are also strongly light-rare-earth-element- (LREE) depleted (Ce_N/Yb_N 0.30–0.62) and have unfractionated heavy rare earth element (HREE) patterns. The komatiites have high Os concentrations (up to 7.0 ppb), low but variable Re/Os ratios, and define an isochron with an age of 270±21 Ma, and an initial ¹⁸⁸Os/¹⁸⁷Os ratio of 0.12506± 0.00041 (_Os=+0.02±0.40). The Os isotopic systematics of the komatiites show no effects of crustal contamination. In contrast, their initial _Nd values range from +3 to +8, reflecting varying but generally small degrees of contamination with Proterozoic sialic basement material. Associated low-Ti basalts have low initial _Nd values (–0.8 to –7.5), high initial _Os values (15), flat or LREE-enriched REE patterns, and Nb-Ta depletion. These characteristics are also attributed to variable extents of crustal contamination.Editorial responsibility: T.L. Grove  相似文献   

Predicting Blast-induced Ground Vibration in Quarries Using Adaptive Fuzzy Inference Neural Network and Moth–Flame Optimization     

Bui  Xuan-Nam  Nguyen  Hoang  Tran  Quang-Hieu  Nguyen  Dinh-An  Bui  Hoang-Bac 《Natural Resources Research》2021,30(6):4719-4734

Natural Resources Research - Blasting is a first preparatory stage that plays a fundamental role in the subsequent operations of an open pit mine. However, its adverse effects can seriously affect...  相似文献   

High-resolution simulations for Vietnam - methodology and evaluation of current climate     

Jack Katzfey  Kim Nguyen  John McGregor  Peter Hoffmann  Suppiah Ramasamy  Hiep Van Nguyen  Mai Van Khiem  Thang Van Nguyen  Kien Ba Truong  Thang Van Vu  Hien Thuan Nguyen  Tran Thuc  Doan Ha Phong  Bang Thanh Nguyen  Tan Phan-Van  Trung Nguyen-Quang  Thanh Ngo-Duc  Long Trinh-Tuan 《Asia-Pacific Journal of Atmospheric Sciences》2016,52(2):91-106

To assist the government of Vietnam in its efforts to better understand the impacts of climate change and prioritise its adaptation measures, dynamically downscaled climate change projections were produced across Vietnam. Two Regional Climate Models (RCMs) were used: CSIRO’s variable-resolution Conformal-Cubic Atmospheric Model (CCAM) and the limited-area model Regional Climate Model system version 4.2 (RegCM4.2). First, global CCAM simulations were completed using bias- and variance-corrected sea surface temperatures as well as sea ice concentrations from six Coupled Model Intercomparison Project Phase 5 (CMIP5) global climate models. This approach is different from other downscaling approaches as it does not use any atmospheric fields from the GCMs. The global CCAM simulations were then further downscaled to 10 km using CCAM and to 20 km using RegCM4.2. Evaluations of temperature and precipitation for the current climate (1980-2000) were completed using station data as well as various gridded observational datasets. The RCMs were able to reproduce reasonably well most of the important characteristics of observed spatial patterns and annual cycles of temperature. Average and minimum temperatures were well simulated (biases generally less than 1oC), while maximum temperatures had biases of around 1oC. For precipitation, although the RCMs captured the annual cycle, RegCM4.2 was too dry in Oct.-Nov. (-60% bias), while CCAM was too wet in Dec.- Mar. (130% bias). Both models were too dry in summer and too wet in winter (especially in northern Vietnam). The ability of the ensemble simulations to capture current climate increases confidence in the simulations of future climate.  相似文献