Low-speed Rarefied Gas Microflow Simulations Using the QGD Model with Nonequilibrium Boundary Conditions

The efficient design of microdevices requires a good understanding of the behavior of rarefied thin gas flows in microdevices. Therefore, it is necessary to develop the tools to simulate their behavior. In this paper, various first-order and second-order slip/jump boundary conditions would be implemented into the Quasi-Gas Dynamic (QGD) model through the solver QGDoam in OpenFOAM to achieve a full solver for low-speed rarefied gas microflow simulations. Two typical cases for rarefied gas microflows the backward-facing step microchannels and microcavity gas flows are adopted for investigation in the present work. The obtained simulation results show that the slip and boundary conditions employ well with the QGD model. The QGD simulation results of the prediction of the surface gas temperature and velocity slip on the surfaces are close to those of the Direct Statistical Monte-Carlo (DSMC) simulations

A Study of Semantic and Pragmatic Features of the Adverb “Still” and Its Equivalent “Vẫn” in Vietnamese

In the age of globalization, there is a noticeable increase in the number of English-Vietnamese bilingual speakers. Accordingly, this article describes some of the semantic and pragmatic features of the adverb \"still\" in English and its most common equivalent in Vietnamese “vẫn”. The data consists of 150 English sentences containing the adverb \"still\" and 150 Vietnamese sentences having the function word \"vẫn\" which are extracted from articles, magazines, short stories, poems, novels as well as lyrics. Through qualitative and quantitative methods, a contrastive analysis of these two words can be performed with the hope of contributing to language proficiency

Scientific Research Activities at the University of Danang's Member Universities to Meet the Higher Education Institutions' Quality Assessment Standards

Accreditation of higher education institutions is a mandatory and periodic condition which is reflected in the law No. 34/2018/QH14 dated November 19th, 2018, on amending and supplementing a number of articles of the Law on higher education. Universities are promoting quality accreditation according to the Circular No. 12/2017/TT-BGDĐT dated May 19th, 2017 issued by the Minister of Education and Training, on regulations of accreditation of higher education institutions. If higher education institutions do not meet the quality accreditation standards, they are not allowed increase the enrollment quota. Currently, the quality accreditation work in higher education institutions has helped the universities to properly assess the current status of outstanding problems so that the schools can have a plan to improve the quality, including standards for scientific research. The article analyzes the current status of scientific research activities at the UD's member universities in comparison with the set of university quality accreditation standards and proposes measures to manage this activity at the UD

Vietnam's Electronic Intra-industry Trade: Analysis Based on Grubel-Lloyd Index

The objective of the article is to analyze the influence of key factors on intra-industry trade (IIT) of electronic goods of Vietnam in the period 2011-2020. The IIT is determined using the Grubel-Lloyd index and is estimated with different methods and tests to ensure the reliability of research results. The study results confirm that Vietnam's IIT of electronic products is significantly positively affected by the market size of the partner countries, the difference in economic development levels, the participation in free trade agreements, and the innovation level of our country while being significantly negatively affected by the difference in economic size, the trade imbalance in the electronics industry, and the openness of trading partners. As for the FTAs in effect during the study period, VKFTA, AHKFTA and EVFTA have positive impacts on IIT of electronic products

Tax Administration in Vietnam's E-commerce Environment

Along with the continuous development of the information technology, e-commerce activities are becoming increasingly popular and predominant compared to traditional business activities. The specific characteristics of e-commerce entail the perfection of the tax law system, the improvement of tax officers' professional capacity and the upgrading of the infrastructure serving tax administration and tax collection for the purpose of avoiding revenue losses from the state budget and ensuring a fair business environment for all economic subjects. This paper presents the status quo of the problem and proposes some solutions to enhance the efficiency of tax administration in e-commerce activities in Vietnam

Studying the Situation of Pricing Transfer for Tax Evasion by Foreign -Invested Enterprises in Vietnam

In Vietnam, tax is one of primary income sources and makes up a large proportion of state budget, much of which comes from foreign- invested enterprises. According to the Foreign Investment Agency under the Ministry of Planning and Investment, by 31/12/2014 there had been 101 nations and territories investing in Vietnam with 17.768 projects worth US $252.715 billion. However, according to the inspectors' reports at General Department of Taxation in recent years, there have been a considerable loss from pricing transfer for tax evasion from this sector. This article present some theories, forms and signs of pricing transfer and the situation of tax evasion of foreign- invested enterprises in Vietnam

Power Failure Events in Meters and Remote Metering Infrastructure in Reliability Indices Calculation

A three phase electronic meter is capable of recording events such as power failure, over voltage, phase loss, voltage unbalance. This paper studies the application of using power failure events in meter to calculate the reliability indices of Danang Power Company such as SAIFI, SAIDI, MAIFI, CAIDI, CTAIDI, CAIFI, ASAI. Also the author has built the program to calculate the reliability with the Microsoft Access connected to the system to collect data from remote metering infrastructure and information system management (CMIS). Through this program, we can calculates the reliability indices quickly, automatically, exactly, and therefore we can replace calculating reliability with outage data entered manually in the power grid management software at Danang Power Company

Initial Research on Chemical Constituents of Houttuynia Cordata Leaves From Quangnam, Vietnam

After the pretreatment, the chemical subtances in Houttuynia Cordataleaf are extracted inn-hexane, chloroform, ethyl acetate, and methanolsolvents. Among those extracts, the chloroform extract shows the highest antioxidant activity when using1,1-diphenyl-2-picrylhydrazyl (DPPH) as free radical scavenging assay. The constituents of those extracts are investigated using gas chromatography–mass spectrometry. In which, the chloroform extract shows the highest number with 28 compounds identified. Three compounds, including beta- myrcene, L-menthol and phytol are found in a high concentration in the 4 above extracts. The compound HC2, known as aristolactam BII, is isolated from chloroform extract with its structure clearly identified using nuclear magnetic resonance (1H and 13C-NMR), as well as compared with the reported data