Vietnam Academy of Science and Technology: Journals Online
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Effective medium approximation for conductivity of coated-inclusion composites with anisotropic coating
No full textEffective medium approximations are constructed in this paper to estimate the macroscopic conductivity of coated-inclusion composites with thin anisotropic coating. The two-phase coated-inclusion are substituted by equivalent one-phase inclusion, using the multi-coated spheres assemblage and the differential substitution approaches. Then, the usual effective medium approximation schemes are applied to the equivalent medium to estimate the conductivity of original three-phase composites. The results obtained were compared with the numerical simulation by finite element method in 2D show the effectiveness of the methods
A nutrient method for cutivation of macroalgae Ulva papenfussii
Get PDFMacroalgae species of the genus Ulva are widely distributed in the wild. Many species of this genus has been used as food as an attractive material for the study of materials, fuels, food etc.. In this paper, we are focusing on nutrient method for cultivation of Ulva papenfussii and A nutrient source for cultivation of U. papenfussii was also investigated with the perspective of utilizing the produced biomass for feed. U. papenfussii is fragmented into 1 × 1 cm size, then it keep in Ulva extract of 0.1 g/l concentrate for 7 days. Then continue to keep fragments in the following conditions: 20 ml/l of PES medium, 700 μmol photon/m2/s of light, 25oC of temperature, 3% of salinity, 28 days of time. Under this condition the productivity U. papenfussii was 17.8 g/l of weight and its growth rate was 4.3–6.5% day. Nutritional cultivation is successful for U. papenfussii speceies, which is of great importance to study the potential of producing seaweed varieties like blades for commercial application of seaweed species.
Expression of Oryza sativa galactinol synthase gene in maize (Zea may L.)
Get PDFGalactinol synthase (GolS) is a key biological catalyst for the synthesis of the raffinose oligosaccharides (RFOs) which play important roles in abiotic stress adaptation of plants, especially drought tolerance. GolS gene has been isolated on a variety of plants in order to create material resources for generating transgenic plants resistant to adverse environmental factors. In our previous research, we have isolated a GolS gene from drought stress cDNA library of Oryza sativa L. Moctuyen (named OsGolS). In this study, the expression vector pCAM-Rd/OsGolS carrying the isolated OsGolS gene under the control of stress-inducible Rd29A promoter was constructed and introduced into Agrobacterium tumefaciens LBA4404, which was used for maize transformation. PCR and Real-time PCR assay indicated that transgene was integrated in the genome of the regenerated Zea mays plants. Reverse transcription-PCR showed that the OsGolS was transcribed into mRNA in Zea mays and was highly expressed. These results provide a basis for the study of the function of OsGolS in drought responses and for the development of drought stress tolerant crops.
Evaluation of the genetic diversity of Huperzia serrate by rapd markers
Get PDFHuperzia serrata, a valuable pharmaceutical plant distributed in Lao Cai (Northwest Vietnam) and Lam Dong (Central Highlands of Vietnam), is known as pharmaceutical materials for the treatment of Alzheimer’s disease. As a result of over-exploitation and habitat fragmentation, H. serrata has become a threatened plant in Vietnam, China and other countries around the world. For the understanding of population dynamics, adaptation, evolution and conservation of plant species in general and H. serrata in particular, the evaluation of genetic diversity is very important. In this study, a total of sixteen RAPD primers were used for evaluation of the genetic diversity of eight H. serrata samples collected from different locations of Sa Pa and Da Lat. Overall, sixteen markers generated a total of 70 fragments in 8 collected samples of H. serrata. Of seventy generated fragments, 44 were found to be polymorphic. The number of fragments of each primer ranged from 1 to 8 with an average of 4,4 fragments per primer. The OPB20 primer revealed the highest polymorphism, while the OPB15, OPB17 and OPC12 primers gave the lowest. Polymorphism information content (PIC) values varied from 0.5266 to 0.8624 with an average of 0.7182, in which the highest value belonged to OPB11 primer while the OPC10 primer showed the lowest PIC value. The dendrogram created based on RAPD data sheet divided the investigated strain into two major groups corresponding to their habitat: Group I included three Da Lat samples (DL1, DL2, DL3) and Group II consisted of five samples from Sa Pa (SP1, Sp2, SP3, Sp4, and SP5). The results of our study could be useful for the conservation and development of H. serrata.
Recreational and conservative valuation of Bien Ho landscape
No full textBien Ho is one of the volcanic landscapes showing lava eruptions that occurred millions of years ago. It is a symbol of the volcanic landscapes in the Tay Nguyen, Vietnam, which keeps a lot of values. This article aimed to quantify recreational and conservative values. The travel cost and contingent valuation method were used to estimate the recreational and conservative value (existence, bequest, and option value) of Bien Ho, respectively. The results indicated that the recreational and conservative value of Bien Ho volcanic landscape was 1,436.9 billion VND and 38.6 billion VND, respectively. The average willingness to pay in the contingent valuation method was 39,388 VND and depended only on ethnicity and age. The study used different populations to define survey samples according to each estimating method to improve the confident accuracy of the results
Distribution and descriptive characteristics of the two giant pill millipedes of the genus Sphaerobelum Verhoeff, 1924 (Diplopoda, Sphaerotheriida, Zephroniidae) in Vietnam
Get PDFTwo giant pill millipedes, Sphaerobelum clavigerum Verhoeff, 1924 and Sphaerobelum hirsutum Verhoeff, 1924, were described from unindicated localities in northern Vietnam. The paper presents the recorded localities, descriptions and colour illustrations of those giant pill millipedes. S. clavigerum Verhoeff, 1924 is recorded from Cuc Phuong National Park (Ninh Binh Province), and distinguished from its congeners by body being shiny, glabrous, anterior telopods 3-segmented, process of 2nd podonomere of posterior telopods slender, not apically strongly swollen. In contrast, S. hirsutum Verhoeff, 1924 is found in Tam Dao National Park and Me Linh Biodiversity Station (both in Vinh Phuc Province), and recognized by body being densely hairy, process of 2nd podonomere of posterior telopods apically strongly swollen, spherical, wider than basis of 3rd podomere. In addition, a key to genera of giant pill millipedes is also provided for the Vietnam fauna
A STUDY ON POWER OUTPUT OF HORIZONTAL-AXIS WIND TURBINES UNDER RAIN
Get PDFThe power of the wind turbine are significantly affected by the air conditions of the operating environment. Rain is a widespread phenomenon in many parts of the world especially in Vietnam, so exploring its effect on the power of wind turbines will provide valuable insights into the design of a new wind tower. In this paper, a method and a model is developed to estimate the effect of precipitation by simulating the actual physical processes of the rain drops forming on the surface of the blades of horizontal-axis wind turbines (HAWT), thereby determining optimal wetness, then power and performance respectively. Consequently, it makes a contribution to operation and control strategies for horizontal-axis wind turbines
CÂN BẰNG VẬT LIỆU VÀ KHẢ NĂNG NUÔI BÃI CHO KHU VỰC BỜ BẮC CỬA SÔNG CÁI VỊNH NHA TRANG
Get PDFNha Trang bay is considered one of the 29 most beautiful bays in the world. This is a coastal area with potential for tourism development with many beautiful clean beaches and dozens of large and small islands. In 2016, Nha Trang has attracted 5 million tourists including 1.2 million international tourists. Recently, while the development of tourism in the country tends to slow down, Nha Trang tourism in the period 2011–2016 increased by 19%/year on average. According to the statistics of Khanh Hoa province, Nha Trang tourism occupies 99% of the province. The number of hotels located in the immediate vicinity of Nha Trang’s central beach is 98% within 500 m from the coastline. In order to develop sustainable tourism, in addition to good management and protection of coastal and estuarine beach environments, more attention should be paid to the rehabilitation, expansion and development of the beach in the northern and southern areas to relieve pressure on the central beach and expand the investment potential and tourism development of Nha Trang city. According to survey data and the calculations based on a local project between Institute of Oceanography and Khanh Hoa province: "Identifying areas capable of rehabilitating and developing artificial beach and proposing solution for protection of natural beaches in Nha Trang Bay" (2014–2016), three beach nourishment scenarios have been simulated and evaluated, suggesting a number of potential areas for rehabilitation and artificial nourishment for the western coast of Nha Trang bay.Vịnh Nha Trang được đánh giá là một trong 29 vịnh biển đẹp nhất trên thế giới. Đây là vùng biển ven bờ có tiềm năng phát triển du lịch với nhiều bãi tắm sạch đẹp và hàng chục đảolớn nhỏ bao quanh . Năm 2016 Nha Trang đã đón 5 triệu khách du lịch trong đó đó có 1,2 triệu khách du lịch quốc tế. Trong thời gian gần đây, trong khi phát triển du lịch của cả nước có xu thế chững lại thì du lịch Nha Trang trong giai đoạn 2011-2016 tăng bình quân 19% /năm. Theo số liệu thống kê của tỉnh Khánh Hòa du lịch Nha Trang chiếm 99% tỷ trọng du lịch của cả tỉnh . Số cơ sở lưu trú trong vùng liền kề bãi tắm trung tâm của Nha Trang thì 98% nằm trong vòng 500m tính từ đường bờ biển vào đất liền... Để phát triển du lịch một cách bền vững ngoài việc quản lý, bảo vệ tốt môi trường bãi vùng ven bờ và cửa sông cần đặc biệt chú ý tới việc cải tạo , mở rộng và phát triển bãi ở các khu vực phía bắc và nam để giải tỏa áp lực cho bãi tắm trung tâm và mở rộng khả năng đầu tư và phát triển du lịch của Nha Trang. Từ các số liệu khảo sát và tính toán trên cơ sở của ĐTKĐNCKH với SKHCN KH “Xác định các khu vực có khả năng cải tạo, phát triển bãi tắm nhân tạo và đề xuất các phương án bảo vệ bãi tắm tự nhiên trong vịnh Nha Trang“ (2014-2016) chúng tôi muốn đưa ra một số phương án phát triển bãi (nuôi bãi), kết hợp công trình là các phương pháp hiện đại dựa trên các nguyên tắc cân bằng và đảm bảo sinh thái cho vùng ven bờ hiện nay (qua nhiều năm tổng kết , đánh giá là rất tích cực) đang được nhiều quốc gia trên thế giới triển khai
A NEW APPROACH TO EXACT PATTERN MATCHING
Get PDFIn this paper we introduce a exible approach to design an eective algorithm for exactpattern matching, and compare it with some of the most ecient algorithms, such as AOSO, EBOM,FJS, FSBNDM, HASHq, LBNDM, SA, BMH-SBNDM, SBNDMq, TVSBS. These results are basedon the concept of the degree of fuzziness presented by P. T. Huy et al. in 2002. Theoretical analysesand experimental results indicate that in practice our proposed algorithm is faster than the abovementioned algorithms in most of the cases of patterns and alphabets
Presence of trace elements in sediment of Can Gio mangrove forest, Ho Chi Minh city, Vietnam
No full textCan Gio mangrove forest (CGM) is located downstream of Ho Chi Minh City (HCMC), situated between an estuarine system of Dong Nai - Sai Gon river and a part of Vam Co river. The CGM is the largest restored mangrove forest in Vietnam and the UNESCO’s Mangrove Biosphere Reserve. The CGM has been gradually facing to numeric challenges of global climate change, environmental degradation and socio-economic development for the last decades. To evaluate sediment quality in the CGM, we collected 13 cores to analyze for sediment grain size, organic matter content, and trace element concentration of Cd, Cr, Cu, Ni, Pb, Zn. Results showed that trace element concentrations ranged from uncontaminated (Cd, Cu, and Zn) to very minor contaminated (Cr, Ni, and Pb). The concentrations were gradually influenced by suspended particle size and the mangrove plants.ReferencesAnh M.T., Chi D.H., Vinh N.N., Loan T.T., Triet L.M., Slootenb K.B.-V., Tarradellas J., 2003. 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