Study of impurity in blue spinel from the Luc Yen mining area, Yen Bai province, VietnamImpurities present in light and saturated cobalt-blue spinel samples collected from Luc Yen mining area (Vietnam) have been studied in details. By using different techniques, including EMPA, UV-VIS-NIR, ESR and XAS, the existence of impurities V, Mn, Ni, Zn, Ti, Cr, Fe, Co, and Ca were identified. Among those impurities, the oxidation state o...
9 trang | Chia sẻ: honghp95 | Ngày: 30/11/2020 | Lượt xem: 463 | Lượt tải: 0
Improvement of the accuracy of the quasigeoid model VIGAC2017Above represented research results show, that on the base of solving the task of fitting the initial quasigeoid model VIGAC2017 to the 194 national quasigeoid heights got from the 194 GPS/first and second orders levelling quasigeoid heights by the least squares collocation, the accuracy of the this model has been increased to to 20,69 %. Tha...
8 trang | Chia sẻ: honghp95 | Ngày: 30/11/2020 | Lượt xem: 466 | Lượt tải: 0
Inverse analysis for transmissivity and the Red river bed's leakage factor for Pleistocene aquifer in Sen Chieu, Hanoi by pumping test under the river water level fluctuationThe determination of the exact boundary condition kinds, boundary values and aquifer parameters values for the areas along the Red river as well as for the areas of boundary of the Pleistocene aquifer with the bed rock in the West and South-West areas of the Red river plain have a very important role in the of the natural groundwater resourc...
13 trang | Chia sẻ: honghp95 | Ngày: 30/11/2020 | Lượt xem: 543 | Lượt tải: 0
Determination of ground displacement of 25 April 2015 Nepal earthquake by GNSS precise point positioningTo monitor the effect of the earthquake with the magnitude of 7.8 on 25 April 2015 in Nepal, we collected and processed GNSS data at 17 stations around the epicenter by using the GNSS PPPC method. The GNSS station displacements are calculated precisely with an accuracy of 1cm in the horizontal and the vertical components. These displacements ...
9 trang | Chia sẻ: honghp95 | Ngày: 30/11/2020 | Lượt xem: 560 | Lượt tải: 0
Estimation of errors in determination of main parameters of earthquake hypocenter, recorded by the national seismic network of VietnamThe results of error estimation of epicenter coordinates and focal depth, recorded by the national network of 30 seismic stations of Vietnam allow drawing the following conclusions: The existing national seismic station network of Vietnam allows determining epicenter coordinates and focus depth in most of Vietnam territory with the errors Δh ≤...
16 trang | Chia sẻ: honghp95 | Ngày: 30/11/2020 | Lượt xem: 564 | Lượt tải: 0
Land cover mapping in Yok Don National Park, Central Highlands of Viet Nam using Landsat 8 OLI imagesFor developing a detailed forest cover map, where the region is the tropical monsoon, along of the rainy season and the dry season is distinctive, with evergreen and deciduous forests. The first: optical satellite data from the dry season to help us accurately distinguish of evergreen forests and deciduous forests. The results indicated that to...
14 trang | Chia sẻ: honghp95 | Ngày: 30/11/2020 | Lượt xem: 560 | Lượt tải: 0
Assessment and Simulation of Impacts of Climate Change on Erosion and Water Flow by Using the Soil and Water Assessment Tool and GIS: Case Study in Upper Cau River basin in VietnamFrom the results, in Upper Cau River system, it includes that the total annual runoff tends to increase compared with the baseline under the climate-change scenario B2. The change's rate of the later periods is bigger than the previous ones, appropriate with the changing tendency of evaporation and rainfall, which are the most important factor...
17 trang | Chia sẻ: honghp95 | Ngày: 30/11/2020 | Lượt xem: 568 | Lượt tải: 0
Application of directional derivative method to determine boundary of magnetic sources by total magnetic anomaliesBy studying and applying the directional gradient of magnetic anomaly field to determine the boundaries of magnetized objects based on numerical models as well as actual magnetic anomaly data in Tuan Giao area, it is possible to make the following remarks: In case the magnetic anomaly sources are narrow in width and their structure extends in...
16 trang | Chia sẻ: honghp95 | Ngày: 30/11/2020 | Lượt xem: 508 | Lượt tải: 0
Mapping land cover using multi-Temporal sentinel-1A data: A case study in HanoiThe proposed method in this paper allows classifying land cover maps in delta area with complex land cover types. However, the limitations of SAR image, including terrain shadows, speckle noise, and similarity in the surface texture of land cover objects can cause confusions in classification result. By combining standard deviation, mean backsca...
15 trang | Chia sẻ: honghp95 | Ngày: 30/11/2020 | Lượt xem: 540 | Lượt tải: 0
Preliminary study on phytogeography of Dipterocarpaceae Blume family in VietnamAnalyzing geographical distribution of the Dipterocarps family of Vietnam shows that family has concentrately distributed in Indochinese floristic region, concurring with originative centre in Burma (Myanmar). There are 5 endemic species for 4 floristic provinces, covering whole Vietnam territory, belonging to Indochinese floristic region, whil...
8 trang | Chia sẻ: honghp95 | Ngày: 30/11/2020 | Lượt xem: 603 | Lượt tải: 0
