65 research outputs found

    THE INFRASTRUCTURE AND ENVIRONMENT IN THE OLD TENEMENTS IN HANOI

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    Joint Research on Environmental Science and Technology for the Eart

    Using SiO2 nano-particles for better color uniformity and lumen output in 8500 K conformal and in-cup white LEDs

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    In the effort of improving the performance of white light LEDs devices (WLEDs), the SiO2 nano-particles were applied and have shown a significant impact on the optical properties. Specifically, the light output of the lighting devices is enhanced when a mixture of SiO2 particles and silicone gel is diffused on the encapsulation layer surface. This enhancement is the result of light scattering from SiO2 that strengthens the emitted blue light at further angles and reduces the color discrepancy. The evidence is that CCT deviation in SiO2-doped structure decline from 1000 K to 420 K in -70° to 70°. In addition, the SiO2 with refractive index in between the phosphor material and outside environment allows light to be emitted outward more effectively. This lighting enhancement of SiO2-doped structure increases the lumen output by 2.25% at 120 mA power source in comparison to structure without SiO2. These experimental outcomes suggest that SiO2 is an effective material to add in WLEDs structure for better lighting efficiency

    Economic impact of climate change on agriculture: a case of Vietnam

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    Food security, agricultural exports, and livelihoods have improved by rapid agricultural expansion in the previous 30 years. In the coming decades, warming trends and human pressures are expected to exacerbate the impact of climate change on agriculture. A time series of data from 1990 to 2020 examines the economic effects of climate change on Vietnamese farm production. After using the Augmented Dickey-Fuller and Philips-Perron unit root tests, the ARDL bounds testing technique estimates short and long-run cointegration. They found long-run cointegration between the variables. A positive influence of CO2 emissions is identified, although negative impacts of average temperature and rainfall are found. But only in the short term can energy consumption benefit agriculture. Non-climatic factors like crop production and fertiliser consumption have beneficial short- and long-term impacts on agriculture production and yield. Juselius Jhansen As well as proving long-term cointegration between variables. The report advises the Vietnamese government to create and implement many adaptation programmes to preserve the agriculture industry from climate change.Nguyen Van Huong (Faculty of Economics, Hung Yen University of Technology and Education (UTEHY)), Bui Thi Minh Nguyet (Vietnam National University of Forestry), Hoang Van Hung (Faculty of Economics, Hung Yen University of Technology and Education (UTEHY)), Hoang Minh Duc (Faculty of Economics, Hung Yen University of Technology and Education (UTEHY)), Nguyen Van Chuong (University of Financial and Business Administration (UFBA)), Do Minh Tri (Nguyen Van Linh Political School), Phung Van Hien (National Academy of Public Administration (NAPA))Includes bibliographical references

    Genetic diversity of gac [Momordica cochinchinensis (Lour.) Spreng] accessions collected from Mekong delta of Vietnam revealed by RAPD markers

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    Abstract Gac (Momordica cochinchinensis (Lour.) Spreng) (2n = 28) belongs to the Cucurbitaceae family. It is indigenous throughout in Vietnam as well as in South East Asia. To estimate the genetic diversity, 20 gac accessions collected in Mekong river delta were analyzed using 10 RAPD primers. Total of 126 fragments were obtained from ten RAPD primers, with 114 polymorphic fragments, and average of 11.4 fragments per primer. The high level of polymorphism (90.4%) was found across 20 gac accessions. The high est Nei's gene diversity value among gac accessions was H = 0.40, and the lowest was H = 0.29 with a mean of 0.36. The highest Shannon diversity index value among gac accessions was H' = 0.58 and the lowest was H' = 0.46 with an average of 0.53. Cluster analysis for genetic relationship between accessions displayed that 20 gac accessions grouped into four main clusters which genetic distance coefficient ranged from 0.29 to 0.64 and with an average of 0.54. There were defined groups according to their locations. According to these results, RAPD technique can be useful tool in genetic diversity evaluation of gac. The information achieved could also be useful for gac breeding program, cultivar differentiation and conservation

    Reservoirs optimization with dynamic programming

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    Differential Evolution (DE) and Dynamic Programming (DP) are important optimal methods in reservoir regulation. In the previous work [1], we presented the outline of DE, and applied it into Pleikrong reservoir, a big one in the Highland of Vietnam for dry season of 2010 year. Continuing from that, in this work, we present the outline of DP and then again, apply it to Pleikrong reservoir; and also apply it to Ialy, the biggest reservoir in Sesan cascade in the Highland of Vietnam; to reach optimal regulation for the maximum power production in the dry season of two years: 2010 and 2012. The results getting from DP are compared to the results by using DE. The results by these two methods have the same trend of releases which is storing the water at the beginning and significantly releasing at the end of the calculation time

    Safety and efficacy of fluoxetine on functional outcome after acute stroke (AFFINITY): a randomised, double-blind, placebo-controlled trial

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    Background Trials of fluoxetine for recovery after stroke report conflicting results. The Assessment oF FluoxetINe In sTroke recoverY (AFFINITY) trial aimed to show if daily oral fluoxetine for 6 months after stroke improves functional outcome in an ethnically diverse population. Methods AFFINITY was a randomised, parallel-group, double-blind, placebo-controlled trial done in 43 hospital stroke units in Australia (n=29), New Zealand (four), and Vietnam (ten). Eligible patients were adults (aged ≥18 years) with a clinical diagnosis of acute stroke in the previous 2–15 days, brain imaging consistent with ischaemic or haemorrhagic stroke, and a persisting neurological deficit that produced a modified Rankin Scale (mRS) score of 1 or more. Patients were randomly assigned 1:1 via a web-based system using a minimisation algorithm to once daily, oral fluoxetine 20 mg capsules or matching placebo for 6 months. Patients, carers, investigators, and outcome assessors were masked to the treatment allocation. The primary outcome was functional status, measured by the mRS, at 6 months. The primary analysis was an ordinal logistic regression of the mRS at 6 months, adjusted for minimisation variables. Primary and safety analyses were done according to the patient's treatment allocation. The trial is registered with the Australian New Zealand Clinical Trials Registry, ACTRN12611000774921. Findings Between Jan 11, 2013, and June 30, 2019, 1280 patients were recruited in Australia (n=532), New Zealand (n=42), and Vietnam (n=706), of whom 642 were randomly assigned to fluoxetine and 638 were randomly assigned to placebo. Mean duration of trial treatment was 167 days (SD 48·1). At 6 months, mRS data were available in 624 (97%) patients in the fluoxetine group and 632 (99%) in the placebo group. The distribution of mRS categories was similar in the fluoxetine and placebo groups (adjusted common odds ratio 0·94, 95% CI 0·76–1·15; p=0·53). Compared with patients in the placebo group, patients in the fluoxetine group had more falls (20 [3%] vs seven [1%]; p=0·018), bone fractures (19 [3%] vs six [1%]; p=0·014), and epileptic seizures (ten [2%] vs two [<1%]; p=0·038) at 6 months. Interpretation Oral fluoxetine 20 mg daily for 6 months after acute stroke did not improve functional outcome and increased the risk of falls, bone fractures, and epileptic seizures. These results do not support the use of fluoxetine to improve functional outcome after stroke

    HANOÏ – La Citadelle sous l’occupation militaire française 1887-1954 Évolution du plan de la citadelle

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    Rapport d'étude HANOÏ-La Citadelle sous l'occupation militaire française 1887-1954 Évolution du plan de la citadelle IICS KINH THÀNH VIỆN NGHIÊN CỨU Institute of Imperial Citadel Studies VIỆN NGHIÊN CỨU KINH THÀNH (IICS) là tổ chức nghiên cứu khoa học trực thuộc Viện Hàn lâm Khoa học xã hội Việt Nam, chuyên sâu nghiên cứu về kinh thành cổ Việt Nam, tư vấn thiết kế trưng bày bảo tàng và nghiên cứu bảo tồn di sản văn hóa Việt Nam. INSTITUTE OF IMPERIAL CITADEL STUDIES (IICS) is a scientific organization under the Vietnam Academy of Social Sciences, specialize in studying Vietnamese ancient citadels, consulting and designing museum exhibitions; researching and preserving Vietnamese culture

    Effect of addition of nanoclays on properties of vinyl ester

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    Vinyl ester resins have been used in many engineering applications such as matrix for composites used in ships, chemical reservoirs, pipes etc. It is desirable to enhance a few important properties of the resin such as flammability resistance, water absorption resistance, and fracture toughness. The addition of nanoclays has been shown to enhance these properties of epoxy resins. The work in this project is to investigate the effect of adding nanoclays on these properties of vinyl ester. Commercial vinyl esters usually contain styrene, which serves both as a diluent and a crosslinking agent. The presence of styrene complicates the incorporation of clays into the vinyl ester. As such two types of vinyl ester were used. One is commercial vinyl ester (Derakane 411- 350) which contains styrene, and the other is vinyl ester synthesized in the laboratory, which is kept free of styrene during the clay incorporation. Different types of clays were examined. Different methods of mixing the clays in the vinyl ester were investigated. The results show that among the different clays, composites made using vinyl ester and Cloisite 20A show better performance. If the mixing conditions are right, there is significant improvement in fracture toughness. However there is some reduction in flexural strength upon the addition of the clays.Peer reviewed: YesNRC publication: Ye
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