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  • 1
    Online Resource
    Online Resource
    Application of hysplit model to evaluate the relationship between meteorological parameters and PM10 content in the atmospheric environment in Ha Noi city, Vietnam
    Viet Nam National University Ho Chi Minh City ; 2020
    In:  Science & Technology Development Journal - Engineering and Technology Vol. 3, No. 2 ( 2020-08-16), p. First-
    Details
    In: Science & Technology Development Journal - Engineering and Technology, Viet Nam National University Ho Chi Minh City, Vol. 3, No. 2 ( 2020-08-16), p. First-
    Abstract: Meteorology is one of the factors that plays an important role in assessing the quality of the atmospheric environment. Regarding the air pollution, especially dust and gaseous emissions, there are currently few studies on the relationship between meteorological factors and the increase in pollutant concentration. In this study, the relationship between several meteorological parameters such as temperature (TEM), wind speed (WS), wind direction (WD) and PM10 content in Hanoi were evaluated through the Spearman correlation coefficient (r) by SPSS statistical analysis software. Data includes hourly meteorological factors (temperature, wind speed and wind direction) and 24-h PM10 concentration collected at three automatic air quality monitoring stations in Hanoi in 2018. In addition, HYSPLIT model is used to determine the influence of wind direction and contribution of air pollution sources. The results show a negative correlation (r 〈 0) between PM10 content, temperature and wind speed in dry and rainy seasons. During the dry season, Hanoi has a higher PM10 content than the remaining months of the year. This might be partly affected by outside pollution sources from the North and Northwest. The findings emphasize the dependence of air quality on local meteorological conditions and the distribution of major
    Type of Medium: Online Resource
    ISSN: 2615-9872 , 2615-9872
    URL: Article
    DOI: 10.32508/stdjet.v3i2.715
    Language: Unknown
    Publisher: Viet Nam National University Ho Chi Minh City
    Publication Date: 2020
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  • 2
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    Online Resource
    Applying higher order stochastic averaging method to the Van der Pol system with timedelay under random excitation
    Viet Nam National University Ho Chi Minh City ; 2019
    In:  Science and Technology Development Journal - Natural Sciences Vol. 2, No. 2 ( 2019-05-18), p. 102-109
    Details
    In: Science and Technology Development Journal - Natural Sciences, Viet Nam National University Ho Chi Minh City, Vol. 2, No. 2 ( 2019-05-18), p. 102-109
    Abstract: The paper investigated the Van der Pol system with time-delay under random excitation by the higher stochastic averaging method. The original system was expressed in terms without time-delay under the assumption that the state variabled of the system were slowly varying processed. Then the higher stochastic averaging method was applied on the approximation system. By this technique, the analytical expression of the stationary probability density function for the Van der Pol system with time-delay under random excitation was showed in higher order approximation for the first time. Effects of the parameter time-delay on the system’s response were investigated. The analytical results were suited well to numerical ones obtained by Monte-Carlo method. It was also showed that the higher order averaging solution was better than the one obtained by the traditional stochastic averaging method.
    Type of Medium: Online Resource
    ISSN: 2588-106X , 2588-106X
    URL: Article
    DOI: 10.32508/stdjns.v2i2.742
    Language: Unknown
    Publisher: Viet Nam National University Ho Chi Minh City
    Publication Date: 2019
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  • 3
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    Applications of optimization methods in designing energy-efficient buildings
    Viet Nam National University Ho Chi Minh City ; 2016
    In:  Science and Technology Development Journal Vol. 19, No. 2 ( 2016-06-30), p. 98-108
    Details
    In: Science and Technology Development Journal, Viet Nam National University Ho Chi Minh City, Vol. 19, No. 2 ( 2016-06-30), p. 98-108
    Abstract: Energy efficiency in buildings is one of the top criteria, accounting for a large weight in the evaluation criteria of Green building rating tools such as LEED, BREEAM, LOTUS, ... Therefore high energy saving is the most important objective that green buildings should achieve. This article provides an overview of optimization methods in mathematics (problems of finding maxima, minima of a function) and the development of applications so as to integrate it into building design. Two typical case studies are used to illustrate the design method. The first is a naturally ventilated apartment building whose design is optimized with the particle swarm optimization, achieving maximum thermal comfort. The second case was a multi-objective optimization problem, in which an airconditioned dwelling is optimized by an evolutionary algorithm to minimize energy consumption while still maintaining reasonable construction cost.
    Type of Medium: Online Resource
    ISSN: 1859-0128 , 1859-0128
    URL: Article
    DOI: 10.32508/stdj.v19i2.657
    Language: Unknown
    Publisher: Viet Nam National University Ho Chi Minh City
    Publication Date: 2016
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  • 4
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    Study on dose rate distribution inside diagnostic X-ray room by using MCNP5 code
    Viet Nam National University Ho Chi Minh City ; 2013
    In:  Science and Technology Development Journal Vol. 16, No. 4 ( 2013-12-31), p. 35-42
    Details
    In: Science and Technology Development Journal, Viet Nam National University Ho Chi Minh City, Vol. 16, No. 4 ( 2013-12-31), p. 35-42
    Abstract: In this paper, the scattering influence on image quality and radiation safety because of changing room size was studied. To estimate the radiation safety in X-ray room, the exact determination of dose rate distribution inside the room and absorbed dose rate for patient is the first task. The authors simulated the dose rate distribution inside diagnostic X-ray room at Nhi Dong hospital with using MCNP5 code. The dependence of dose rate distribution on various peak voltages of X-ray tube was also investigated in this study
    Type of Medium: Online Resource
    ISSN: 1859-0128 , 1859-0128
    URL: Article
    DOI: 10.32508/stdj.v16i4.1594
    Language: Unknown
    Publisher: Viet Nam National University Ho Chi Minh City
    Publication Date: 2013
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  • 5
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    Online Resource
    Impact of Nucleic Acid Testing (NAT) on screening blood donors at a tertiary center in Vietnam
    Viet Nam National University Ho Chi Minh City ; 2020
    In:  Science & Technology Development Journal - Health Sciences ( 2020)
    Details
    In: Science & Technology Development Journal - Health Sciences, Viet Nam National University Ho Chi Minh City, ( 2020)
    Abstract: To ensure safe blood transfusion, since June 2015, Nucleic Acid Testing (NAT) technique has been applied in blood screening process in some areas in Vietnam. The objective of our project is to examine the effectiveness of this technique, to provide specific, updated evidence, as the fundamental for promoting the application of NAT technology in screening blood donors. The study describes a series of cases, performed on 412,705 blood donated samples meeting inclusion criteria at Blood Transfusion Hematology Hospital from January 1, 2017 to January 1, 2019. All collected blood samples were screened for HBV, HCV, and HIV by serology technique, then samples with negative results will continue to be screened by NAT technique. Test results and donor information will be stored on the the hospital’s database. As a result, thanks to NAT screening, our study found 369 more positive blood samples with viral genetic material that serology did not detect, of which: 352 samples reacted with HBV-DNA (0.0871%), 10 samples responded to HCV-RNA (0.0025%) and 6 samples responded to HIV-RNA (0.0017%). Therefore, the application of NAT to the blood screening process is necessary to improve the safety of blood transfusion. Regarding the characteristics of positive cases with infectious agents, we recorded a higher rate of positive for HBV, HIV than men, even when tested by serology or by NAT technique (statistically significant, P 〈 0.05); The positive rate for these 3 agents was higher for first-time blood donors than for repeat blood donors, statistically significant with serological screening (P 〈 , 001) and not statistically significant when screening NAT (P 〉 0.05). In conclusion, The application of NAT technology in blood screening is essential and effective, improving blood transfusion safety.
    Type of Medium: Online Resource
    ISSN: 2734-9446
    URL: Article
    DOI: 10.32508/stdjhs.v1i1.443
    Language: Unknown
    Publisher: Viet Nam National University Ho Chi Minh City
    Publication Date: 2020
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  • 6
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    Online Resource
    The innovation of perception and thinking about the state sector’s leading role in the Vietnamese socialist-oriented market economy
    Viet Nam National University Ho Chi Minh City ; 2014
    In:  Science and Technology Development Journal Vol. 17, No. 2 ( 2014-06-30), p. 6-14
    Details
    In: Science and Technology Development Journal, Viet Nam National University Ho Chi Minh City, Vol. 17, No. 2 ( 2014-06-30), p. 6-14
    Abstract: The state sector playing the leading role is the perception that has been consistently specified in documents of the Communist Party, since the seventh National Congress. The affirmation of the state sector’s leading role is to clarify the nature and characteristics of the socialist-oriented market economy. The leading role of the state sector means the state sector pioneers and leads in the market economy which is reflected by the holding of crucial positions and activities in the economy. After nearly 30 years of reform, the connotations of the leading role of the state sector and the key position of state-owned enterprises have been gradually defined; the state sector and state-owned enterprises have been differentiated. The state sector plays a leading role in a multi-sector economy in which the state-owned enterprises keep a “crucial position” and are a material condition to orient socialism. The state sector, however, is yet to clearly show this role. The state sector has a tremendous influence with some components of it directly affecting the whole economy, which are resources, infrastructure, state budget etc. Because of the above - mentioned reasons, the state sector is the foundation to the social and economic development in the socialist-oriented market economy of Vietnam.
    Type of Medium: Online Resource
    ISSN: 1859-0128 , 1859-0128
    URL: Article
    DOI: 10.32508/stdj.v17i2.1331
    Language: Unknown
    Publisher: Viet Nam National University Ho Chi Minh City
    Publication Date: 2014
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  • 7
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    Issues in developing model of economic zones in Vietnam
    Viet Nam National University Ho Chi Minh City ; 2017
    In:  Science & Technology Development Journal - Economics - Law and Management Vol. 1, No. Q1 ( 2017-06-30), p. 97-111
    Details
    In: Science & Technology Development Journal - Economics - Law and Management, Viet Nam National University Ho Chi Minh City, Vol. 1, No. Q1 ( 2017-06-30), p. 97-111
    Abstract: Economic zone is a special model which plays an important role in the growth and development of a nation. The history of economic zones dates back from the early of 18th century under the form of autonomous regions or free trade areas. After many periods, economic zone has experienced different forms. The paper mainly uses synthesis and comparison methods to show the trend in establishing and developing economic zones in Vietnam. A comparison with the world’s experience is also conducted. The author finds that the model of economic zones in Vietnam has similarities and differences with that of the world and entails shortcoming. Vietnam’s model relies on attracting low-cost labor, available materials and preferential polices. To catch up with the current trend in the world, it is necessary to build a regime or policy which is appealing enough to attract investment capital, high-quality human resource so as to create a gateway for knowledge, science and technology. This is to turn economic zones into a booster for the economic development of the region and the nation.
    Type of Medium: Online Resource
    ISSN: 2588-1051 , 2588-1051
    URL: Article
    DOI: 10.32508/stdjelm.v1iQ1.430
    Language: Unknown
    Publisher: Viet Nam National University Ho Chi Minh City
    Publication Date: 2017
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  • 8
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    Online Resource
    Sulfonated hypercrosslinked adsorbent – synthesis and application in analytical chemistry
    Viet Nam National University Ho Chi Minh City ; 2013
    In:  Science and Technology Development Journal Vol. 16, No. 2 ( 2013-06-30), p. 32-38
    Details
    In: Science and Technology Development Journal, Viet Nam National University Ho Chi Minh City, Vol. 16, No. 2 ( 2013-06-30), p. 32-38
    Abstract: Chromatographic technique becomes more and more popular in analytical chemistry thanks to the diversity of stationary phases. Among the materials hypercrosslinked poly(styrene-co-divinylbenzene-co-vinylbenzyl chloride) is of great interest because of its exceptional high surface area and chemical resistance. Despite the advantages the polymer, its applications are still limited. Its surface is too hydrophobic for hydrophilic analytes therefore several reactions have been used to modify this material. The most popular reaction is sulfonation in which sulfonate group is introduced on to the material surface. In this study chlorosulfonic acid was used as sulfonation reagent, the resulting polymer has two functional groups: sulfonate and sulfonyl chloride. Then sulfonyl chloride group was hydrolyzed by sodium hydroxide to form sulfonate group. The reaction conditions namely ratios of reagent to polymer and reaction time were investigated for high cation exchange capacity. The home-made sulfonated material was sucessfully used as solid phase extraction (SPE) sorbent with high static capacity (10 meqv/g), dynamic capacity (3.8 meqv/g), fast mass transfer, and high enrichment factor.
    Type of Medium: Online Resource
    ISSN: 1859-0128 , 1859-0128
    URL: Article
    DOI: 10.32508/stdj.v16i2.1449
    Language: Unknown
    Publisher: Viet Nam National University Ho Chi Minh City
    Publication Date: 2013
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  • 9
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    Online Resource
    Identification of commensal Pseudomonas aeruginosa isolates using duplex PCR targeting the oprL and algD genes
    Viet Nam National University Ho Chi Minh City ; 2022
    In:  Science and Technology Development Journal Vol. 25, No. 3 ( 2022-11-14), p. 2481-2488
    Details
    In: Science and Technology Development Journal, Viet Nam National University Ho Chi Minh City, Vol. 25, No. 3 ( 2022-11-14), p. 2481-2488
    Type of Medium: Online Resource
    ISSN: 1859-0128
    URL: Article
    DOI: 10.32508/stdj.v25i3.3961
    Language: English
    Publisher: Viet Nam National University Ho Chi Minh City
    Publication Date: 2022
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  • 10
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    Online Resource
    Applying statistical analysis for assessing the reliability of input data to improve the quality of short-term load forecasting for a Ho Chi Minh City distribution network
    Viet Nam National University Ho Chi Minh City ; 2020
    In:  Science & Technology Development Journal - Engineering and Technology Vol. 2, No. 4 ( 2020-02-23), p. 223-239
    Details
    In: Science & Technology Development Journal - Engineering and Technology, Viet Nam National University Ho Chi Minh City, Vol. 2, No. 4 ( 2020-02-23), p. 223-239
    Abstract: Short-term load forecasting has an extremely important role in the design, operation and planning of power system, especially on a power grid of Ho Chi Minh City (HCMC) - an active city has the highest power demand in Vietnam. Through the data survey, the load power in the HCMC area changes suddenly so that it causes disturbances in the load data. Accordingly, the reliability assessment of the load data will be essential in the processing stage of data-filtering before implementing load forecasting models. This study introduces a novel statistical data-filtering method that takes into account the reliability of the input-data source by analyzing many different confidence levels. Results of the proposed data-filtering method will be compared to previous data -iltering methods (such as Kalman, DBSCAN, Wavelet Transform and SSA filtering methods). The data source used in this study was collected from more than 50 substations uisng the SCADA system in Ho Chi Minh City's distribution network and was put into a neural network prediction model - ANN (Artificial Neural Network) and a ARIMA model (Autoregressive Integrated Moving Average), to demonstrate the effectiveness of the proposed data-filtering method. Numerical results derived from ANN and ARIMA predictive models show the effectiveness of the proposed data-filtering method, particularly, when the reliability of real data from the Ho Chi Minh city distribution network is determined at the 95% level, the forecasting results of ANN and ARIMA models using the proposed data-filtering method are obviously better than that without filtering method or using other data-filtering methods.
    Type of Medium: Online Resource
    ISSN: 2615-9872 , 2615-9872
    URL: Article
    DOI: 10.32508/stdjet.v2i4.614
    Language: Unknown
    Publisher: Viet Nam National University Ho Chi Minh City
    Publication Date: 2020
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