http://tainguyenso.vnu.edu.vn/jspui/handle/123456789/60 2026-05-17T15:57:32Z http://tainguyenso.vnu.edu.vn/jspui/handle/123456789/274 The effect of Cu concentration in soil and phosphorous fertilizer on plant growth and Cu uptake by Brassia juncea L. grown on contaminated soils Nguyen, Xuan Cu An experiment was carried out in the greenhouse conditions with Brassica juncea L. grown on alluvial soils that had previously been contaminated at different concentrations of Cu. The main purposes of the research were to determine the effects of Cu and phosphorus applications on plant growth and Cu uptake by Brassica juncea L. Mature plants were harvested for the Cu accumulation analysis. The soil samples from each growing pot were extracted by HNO3 0.43N in order to determine the content of Cu2+ mobilization in soil, while the plant samples were acid digested for determining the total Cu concentration. Atomic Absorption Spectroscopy (AAS) was employed to determine Cu concentrations in soils and plant samples. The results showed that adding Cu to soils has strong effects on Brassica juncea L. growth and the uptake rate of Cu by the plants. The height and the biomass of plants were reduced dramatically by 36% and 53% respectively at the rate of 200 ppm Cu. In addition, phosphorous fertilizer also effectively improved plant growth and reduced Cu concentrations in plant of Brassica juncea. At the application rate of 100 kg P2O5/ha, the height and biomass of plant were increased to 30% and 31% respectively, and the Cu content in plants of Brassica juncea was reduced by 14% comparing with the control samples. VNU Journal of Science, Earth Sciences. Vol. 24 (2008), No. 3, P. 113‐117 2008-01-01T00:00:00Z http://tainguyenso.vnu.edu.vn/jspui/handle/123456789/273 Study on wave prevention efficiency of submerged breakwater using an advanced mathematical model Phung, Dang Hieu The paper presents the results of a numerical study on the interaction of waves and a submerged breakwater. The numerical study is the application of an advanced numerical model named as CMED, which is based on the Narvier-Stokes equations and VOF (Volume of Fluid) method, and has been previously developed by the author. The consideration is paid for the investigation on the influence of the characteristics of the breakwater on the variation of some parameter coefficients, such as reflection, transmission and energy dissipation coefficients. Based on the systematic analysis of the numerical results, the wave prevention efficiency of the breakwater is discussed. The results show that there are an effective range of the water depth at the top of the submerged breakwater and an effective range of the breakwater width in relation to the incident wave length that produces the effective performance of the submerged breakwater regarding to the wave prevention efficiency. The results of this study also confirm that the energy dissipation due to wave breaking processes is one of key issues in the practical design of an effective breakwater. VNU Journal of Science, Earth Sciences. Vol. 24 (2008),No. 3, P. 118‐124 2008-01-01T00:00:00Z http://tainguyenso.vnu.edu.vn/jspui/handle/123456789/272 Thunderstorm forecast technique for Noi Bai Airport Tran, Tan Tien; Nguyen, Khanh Linh; Cong, Thanh; Le, Quoc Huy; Do, Thi Hoang Dung This study briefly summarizes the thunderstorm activities in Vietnam. To predict thunderstorms in the Noi Bai Airport region, the thunderstorm indices are calculated for 64 grid points nearby Noi Bai region from the predicted meteorological fields with RAMS (Regional Atmospheric Modeling System) model. The forecast procedure for thunderstorm is built for this region with four prediction factors, such as CAPEmax, Kimax, SI min, Vtmax in the forecast threshold of 0.6. As a result, the occurrence of thunderstorms reaches 80% for the duration of 36 hours. The procedures may be used in the operational prediction. VNU Journal of Science, Earth Sciences. Vol. 24 (2008), No. 3, P. 125‐132 2008-01-01T00:00:00Z http://tainguyenso.vnu.edu.vn/jspui/handle/123456789/271 Landscape ecological planning based on change analysis: A case study of mangrove restoration in Phu Long - Gia Luan area, Cat Ba Archipelago Nguyen, An Thinh; Nguyen, Xuan Huan; Pham, Duc Uy; Nguyen, Son Tung Mangroves play an important role in coastal zones in many aspects e.g. extremely essential habitats for many species, coastlines protection from natural hazards, and so on. However, in Vietnam, like in other developing countries, these mangrove areas have been destroyed and encroached as a consequence of a poorly planned economic development. The study has been conducted in Phu Long - Gia Luan region, which have the largest mangrove area in the Cat Ba Archipelago Biosphere Reserve, Hai Phong City, Vietnam. The aims of the study are to investigate existing land use conditions, land use changes, as well as driving forces and directions for the changes in order to build a case model of sustainable development; and integrate a mangrove conservation planning into the General Socio - Economic Development Planning Project of Hai Phong City for the period of 2010-2020. The article presents results obtained from study in the period of 2007-2008 in Phu Long - Gia Luan area, including (a) Mangrove area decreased by 98.9 hectares from 1994 (792.3 hectares) to 2006 (693.4 hectares), in which the largest lost is observed in Phu Long southern region, meanwhile Gia Luan region is less changed; (b) There are 12 species belonging to 10 families and two ecological succession series in these mangroves; (c) Planning the area based on principles of landscape ecology for the priority purposes of mangrove restoration up to 2020 so that a mangrove area restored is equal to the area in 1994. The study area is divided into four functional subdivisions: active use subdivision, ecological restoration subdivision, stable use subdivision, and protective subdivision. The value of restored mangrove in Phu Long - Gia Luan is estimated 15,908.45 USD per hectare for shrimp farms through an environment impact assessment and cost-benefit analysis VNU Journal of Science, Earth Sciences. Vol. 24 (2008), No. 3, P. 133‐144 2008-01-01T00:00:00Z