Vietnam Academy of Science and Technology: Journals Online
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Genetic diversity of Panax vietnamensis var. langbianensis populations in Lam Vien plateau - Vietnam detected by inter simple sequence repeat (ISSR) markers
No full textPanax vietnamensis var. langbianensis is a new variety from Lam Vien plateau of Vietnam. In this study, inter simple sequence repeat (ISSR) markers were employed to investigate the genetic diversity and variability of 115 individuals belonging to two naturally distributed populations of this variety, which classified by habitat. Genetic diversity at the taxon level was high (HeT = 0.284 and PPBT = 97.2 %). The result showed lightly higher genetic diversity in population in Lac Duong region (HeLD= 0.228 and PPBLD = 81.5 %) as compared to those located in Dam Rong region (HeDR= 0.213 and PPBDR = 79.4 %). The interpopulation gene differentiation was high (GST Total = 0.221) with the genetic distance among populations was DLD-DR = 0.191. Gene flow within populations was Nm = 0.8793. In Lac Duong population, the genetic diversity of older group (HeLD O = 0.233; PPBLD O = 77.1%) was higher than of younger group (HeLD Y = 0.214; PPBLD Y = 72.4 %) and the intergroup gene differentiation was GSTDL = 0.0205 with the genetic distance between these two group was DLD O-Y = 0.0061 showed the risk of reduction in genetic diversity. In Dam Rong population, the genetic diversity of older group (HeDR O = 0.204; PPBDR O = 75.2 %) was equal to younger group (HeDR Y = 0.209; PPBDR Y = 72.7 %) and the intergroup gene differentiation was GSTDR = 0.0304 with the genetic distance between them was DDR O-Y = 0.01393 showed the stability in genetic diversity. Data for genetic diversity and variation from this study can be used to further investigate and protect this variety for conservation and development purposes and for sustainable exploiting and use of these valuable natural resources
Pliocene - present tectonics and strain rate in Ninh Thuan region and surrounding continental shelf
No full textIn this paper, we present detail data of Pliocene - present tectonics and strain rate from GPS measurement and seismic interpretation. Using international reference frame ITRF08, we revealed absolute tectonic velocities of GPS sites with the slip rate to the east between 22 to 25 mm/year, to the south between 4 to 8 mm/year. The present strain rate was determined from present tectonic velocities that were consistent with the recent strain rates determined from seismic profiles, thickness of Pliocene - Quaternary sediments. Present day strain rate varying from 10 to 30 nano per year indicated that the region has been deformed weakly, in a stable tectonic regime
Evaluating the qualities of probiotic products by a DGGE-based procedure
No full textThe quality of the probiotics is determined by the microbiological composition and can thus be verified by analyzing this characteristic. The use of the Denaturing Gradient Gel Electrophoresis (DGGE) allows the detection of each microorganism through the corresponding band on the gel, which can be considered as the "bar code" of that microorganism. This "bar code” principle demonstrates the potential for the application of DGGE technology to test microbial probiotics with or without a bacterium as registered to assess whether they are qualified. As such, in this study, we experiment the application of DGGE method to test 10 commercial probiotic products, with a focus on products consisting of only bacteria which dominate the market. First, we performed DNA genome extraction and amplification of 550 bp DNA of the 16S rDNA by PCR. Then, the amplicon was analysed on polyacrylamide gels containing a 30% to 60% linear denaturing gradient of urea and formamide. Microbial composition of 7 of the 10 products showed a strong correlation between DGGE results with product labeling as well as isolation of micoorganism. This study thus demonstrates the potential application of DGGE technology in evaluating the qualities of probiotic products
Conservative valuation of typical volcanic landscapes in the Pleiku basaltic plateau: some improvement
No full textThere are tens of typical volcano-related relics such as craters and waterfalls in the Pleiku volcanic plateau, Gia Lai province however, Gia Lai’s tourism has underdeveloped. Thus it is vital finding the specific tourist products to promote the provincial nonsmoking industry. Quantifying conservative values of typical volcanic landscapes in the form of money would provide useful information for decision-makers to plan and develop rural tourism. This study was applied to the contingent valuation method to estimate the conservative values of twenty volcanic landscapes in the Pleiku plateau. The results indicated that Bien Ho volcanic landscape got the highest traditional value with above 38.60 billion VND. Subsequently, the conservative value of Chu Dang Ya was 27.28 billion VND. The value of the Phu Cuong waterfall was also estimated quite highly. Furthermore, our new finding is that there was a close relationship between the results coming from the conservative valuation and the results coming from evaluation, classification of geoheritages based on UNESCO’s criteria adapting in Vietnam. The study figured out that there was a close relationship between the conservative valuation and information accessibility on twenty landscapes by interviewees before
Vibrational Study of the Hydrogen Adsorption on the Missing Row Platinum (110) Surface
Full text linkThe hydrogen vibration was investigated to analyze its affect on the hydrogen adsorption on the missing row platinum surface (H/Pt(110)-(12) model) in the ultrahigh vacuum (UHV). The density functional theory (DFT) combined with the approximation oscillation of the hydrogen atom on the surface was used. When the hydrogen coverage ΘH on the surface is 100% ( = 1 ML), and taking into account the vibrational effect, the bond formed at the edge of the first layer (short bridge) is the most stable site. The vibrational effect on the adsorption model H/Pt(110)-(12) is significant
Two-colour Three-pulse Spectrally Resolved Nonlinear Spectroscopy for Studies of Dynamics in Semiconductor Si Quantum Dots
Full text linkWe demonstrate that a two-colour three-pulsenonlinear spectroscopy can be used to study the dynamics of excited carriers inSi quantum dot structures embedded in SiN. Decays of the transverse optical phonon population and the transverse acoustic phonon population are measured and discussed. A simple theoretical modelis also used to support interpretation of our experimental observations
Theoretical and experimental analysis of the exact receptance function of a clamped-clamped beam with concentrated masses
Full text linkThis paper establishes the exact receptance function of a clamped-clamped beam carrying concentrated masses. The derivation of exact receptance and the numerical simulations are provided. The proposed receptance function can be used as a convenient tool for predicting the dynamic response at arbitrary point of the beam acted by a harmonic force applied at arbitrary point. The influence of the concentrated masses on the receptance is investigated. The numerical simulations show that peak in the receptance will decrease when there is a mass located close to that peak position. The numerical results have been compared to the experimental results to justify the theory
THE ANALYSIS OF FLUID DYNAMICS OF WAVE POWER STATION WITH WELLS TURBIN BY CFD
Full text linkNatural energy such as wind, wave and other natural vibrations is one of the high potential renewable energy sources. The Wells turbine is based on the use of bidirectional turbines, which act as axial-flow self-rectifying turbines that employs a symmetrical blade profile and rotating unidirectionally in reciprocating airflows generated by the air chamber to extract energy from vibrations. These topics have been extensively studied both numerically and experimentally such as research on the parameters of the effects of structure, angle of attack, blade shape, etc. In this paper, numerical simulation is carried out using commercially available tool Fluent for fluid dynamics analysis and focus on oscillating predictions, with particular attention to the behavior of the flow. Based on the Numerical Wave Tank (NWT) model is simulated in a two dimensional used in this model, which is constructed mainly based on the spatially averaged Navier Stokes equation with the k-ε model for simulating the turbulence and modeled with Volume of Fluid (VOF). Axial-flow turbines system and future development as well as the proposed limitations will be discussed in detail
Studying and forecasting the evolution of the Day river coastal zone up to the year of 2070
Full text linkThe Day river coastal zone is the place of plentiful and eventful economical activities and the natural habitat of diverse endemic species that should be preserved and developed. According to the updated geological, remote-sensing and oceanographic data sources, this study figures out the actual state, evolutional history and forecasts the development of the Day river coastal zone up to the year 2070, which could be used to improve the effectiveness of the long-term spatial coastal zone management and master planning. Major conclusions are as follows: (i) The Day river coastline has been highly modified since the last 50 years, (ii) The shoreline seaward development tends to gradually decrease in recent years, and (iii) The river-bed continues to be shifted southwestwards in the context of global climate change and sea level rise.Abstract STUDYING AND FORECASTING THE EVOLUTION OF THE DAY RIVER COASTAL ZONE UPTO THE YEAR 2050 Duong Quoc Hung1, Vu Hai Dang1, Phan Dong Pha1, Nguyen Thi Anh Nguyet1, Ngo Bich Huong1, Nguyen Thai Son2 (1) Institute of Marine Geology and Goephysics; (2) Institute of Geography The coastal geographical features including alluvial grouds, estuaries, mangrove forest, etc. are products of the river - ocean interactions, reflect the dynamic equilibrium of the unsustainable ecosystems that are spacial and temporary changing. These areas are also the places of plentiful and eventful economical activities and the natural diversified endemic habitats to be preserved and developed. According to the updated data sources, this study mentions to the actual state, evolution history and developing forecasts for the Day River coastal zone up to the year of 2050, which could be used to inhale the effectiveness of the long-term spacial coastal zone management and master plannin
Research on the use of calcium carbide residue from the acetylene gas manufacturing factory to produce non-calcined brick
No full textIn Vietnam, calcium carbide residue (CCR) from the acetylene gas factories are not properly treated, causing serious environmental pollution. Based on mineral composition determined by XRD, calcium carbide residue consisted mainly of portlandite (70-72%), calcite (14-16%), hydrocalumite (6-8%), and chemical composition determined by XRF method composed of CaO (53.02%), LOI (39.72%). This calcium carbide residue can be used as a source of hydrated lime, mixed with fly ash, sand, and cement to produce non-calcined bricks and test results show that brick specimens achieved compressive strength 3.0-7.5 MPa, water absorption 12.3-17.5%, density 1.28-1.80kg/cm3. The test bricks satisfied Vietnamese standards for construction bricks