Finite Element Analysis of Cross-Wedge Rolling Process

Dinh Van Hai,Dao Minh Ngung,Nguyen Trong Giang 한국소성가공학회 2010 기타자료 Vol.2010 No.6

In this study, a non-isothermal simulation model for flat-wedged cross-wedge rolling (CWR) to fabricate a bullet was presented by using three-dimensional thermo-rigid-plastic finite element method (FEM). Both deformation behavior and heat transfer of the process were taken into account. Based on the simulation results, the distributions of temperature, stress, strain areas were analyzed. These results could provide theoretical guidance for net shape and reasonable design of tools.

Synthesis of ternary core-shell carbon sphere@α-Fe2O3@Ag composites and their application for simultaneous voltammetric detection of uric acid, xanthine, and hypoxanthine

Ho Van Minh Hai,Dinh Quang Khieu,The Ky Vo,Van Cuong Nguyen,김진수 한국화학공학회 2023 Korean Journal of Chemical Engineering Vol.40 No.3

Core-shell carbon sphere (CS)@α-Fe2O3@Ag was synthesized via a multistep hydrothermal method. First, the D-glucose hydrothermal process was employed to synthesize micron-size CSs on which α-Fe2O3 was grown to obtain the composite sphere of CS@α-Fe2O3. Thereafter, Ag+ was reduced on the surface of the CS@α-Fe2O3 sphere using NaBH4 agent to produce the core-shell CS@α-Fe2O3@Ag. Finally, microsphere composite CS@α-Fe2O3@Ag was coated on a glassy carbon electrode (GCE) to enhance its electrochemical performance in the simultaneous determination of uric acid (UA), xanthine (XN), and hypoxanthine (HP). Results indicated that the CS@α-Fe2O3@Ag-coated GCE exhibited improved voltammetric sensitivity toward UA, XN, and HP compared to bare GCE. The oxidation peak currents of the simultaneous detection of UA, XN, and HP increased linearly in the concentration range of 0.5–8.0 µmol L−1. The detection limits of the fabricated electrodes for UA, XN, and HP were −0.042, 0.089, and 0.048 µmol L−1, respectively, being more sensitive than many other modified GCEs. Moreover, the CS@α-Fe2O3@Ag-coated GCE exhibited good stability and repeatability. This study opens a new perspective for developing highly efficient electrodes for electrochemical analysis.

Critical properties around the ferromagnetic-paramagnetic phase transition in La_0.7Ca_0.3-xA_xMnO₃ compounds (A = Sr, Ba and <i>x</i> = 0, 0.15, 0.3)

Linh, Dinh Chi,Thanh, Tran Dang,Anh, Le Hai,Dao, Van Duong,Piao, Hong-Guang,Yu, Seong-Cho Elsevier 2017 JOURNAL OF ALLOYS AND COMPOUNDS Vol.725 No.-

<P><B>Abstract</B></P> <P>Influence of alkaline earth element doping in the A-site on the structure, magnetic and magnetocaloric properties of La<SUB>0.7</SUB>Ca<SUB>0.3-x</SUB>A<SUB>x</SUB>MnO<SUB>3</SUB> (A = Sr and Ba; <I>x</I> = 0, 0.15 and 0.3) perovskite manganites have been investigated. X-ray diffraction data indicates that samples <I>x</I> = 0 and 0.15 crystallize in the orthorhombic structure (space group <I>Pnma</I>), whereas samples <I>x</I> = 0.3 belong to the rhombohedral structure (space group <I>R</I>-3<I>c</I>). Substitution of Sr or Ba for Ca plays an important role in the increase of Curie temperature (<I>T</I> <SUB>C</SUB>) and modification the nature of the magnetic phase transition in materials. Sample <I>x</I> = 0 exhibits the first-order phase transition (FOPT) with a large magnetic entropy change (Δ<I>S</I> <SUB>m</SUB>), whereas samples <I>x</I> = 0.15 and 0.3 exhibit the second-order phase transition (SOPT) characterizations and the moderate values of Δ<I>S</I> <SUB>m</SUB>. Using the modified Arrott plots method, the critical behaviors around <I>T</I> <SUB>C</SUB> for SOPT samples have been investigated through the values of critical parameters (<I>T</I> <SUB>C</SUB>, <I>β</I>, <I>γ</I>, and <I>δ</I>). We pointed out that Ba-doping favors establishing long-range ferromagnetic order, contrary to the case of Sr-doping.</P> <P><B>Highlights</B></P> <P> <UL> <LI> Sr or Ba-doped La<SUB>0.7</SUB>Ca<SUB>0.3</SUB>MnO<SUB>3</SUB> leads to modify the nature of the phase transition. </LI> <LI> Ba-doping favors establishing long-range FM order, contrast with Sr-doping. </LI> <LI> The effective exponents vary non-monotonically in the asymptotic region. </LI> </UL> </P>

A scintillation detector confi guration for pulse shape analysis

Phan Van Chuan,Nguyen Duc Hoa,Nguyen Xuan Hai,Nguyen Ngoc Anh,Nguyen Nhi Dien,Pham Dinh Khang 한국원자력학회 2018 Nuclear Engineering and Technology Vol.50 No.8

This paper presents a neutron detector configuration using EJ-301 scintillation liquid, a R9420 photomultiplierand a homemade preamplifier. The detector qualities which include the energy linearity, efficiencyresponse and neutron/gamma discrimination are guaranteed for neutron detection in the energyrange from 0 to 3000 keVee. Regarding the neutron/gamma discrimination capability, four pulse shapediscrimination (PSD) methods which are the threshold crossing time (TCT), pulse gradient analysis (PGA),charge comparison (CC) and correlation pattern recognition (CPR), were evaluated and discussed; amongof these, the CPR method provides the best neutron/gamma discrimination

Access to Anti-smoking Information among School Children and its Potential Impact on Preventing Smoking Initiation: Results from the Global Youth Tobacco Use Survey (GYTS) 2014 in Viet Nam

Hoang, Van Minh,Kim, Bao Giang,Phan, Thi Hai,Trinh, Dinh Hoang,Doan, Thu Huyen,Luong, Ngoc Khue,Nguyen, Thuy Linh,Nguyen, Tuan Lam,Pham, Thi Quynh Nga Asian Pacific Journal of Cancer Prevention 2016 Asian Pacific journal of cancer prevention Vol.17 No.no.sup1

Scientific evidence on all aspects of smoking amongst youth is very important for designing appropriate interventions to reduce smoking among this vulnerable population. This paper describes current access to anti-smoking information among school children aged 13 to 15 years in Vietnam in 2014 and examines its potential impact on preventing smoking initiation. The data used in this paper were obtained from the 2014 Global Youth Tobacco Survey (GYTS) in Vietnam. Students were asked questions about their level of awareness of anti-smoking information from various sources in the past 30 days and about lessons in school regarding the dangers of tobacco use during the last 12 months. Those who have never smoked were asked "whether or not they thought about avoiding cigarettes because of health warnings on cigarette packages" and answers were analyzed in combination with data on access to anti-smoking information from other sources. The prevalence of exposure to antismoking campaigns was high among school children in Viet Nam: 55.3% of current smokers reported thoughts of smoking cessation because of health warnings on cigarette packages; 60.5% of never smokers avoided initiating smoking because of the same health warnings. The potential impact of graphic health warnings to prevent school-aged children from smoking initiation would be stronger if there was concurrent access to anti-smoking programs on the dangers of tobacco use in schools. However, school education for tobacco prevention and control has not been as strong as expected. A more comprehensive school curriculum on tobacco prevention and control is recommended to reinforce antismoking messages among school children.

Science beyond English: to what extent do Vietnamese scholars publish in non-English languages?

Hiep-Hung Pham,Van Luong Nguyen,Dinh-Hai Luong 한국과학학술지편집인협의회 2022 Science Editing Vol.9 No.2

Purpose: Although English has become the lingua franca for scholarly communication, scholars worldwide publish in other languages. Nevertheless, few studies have answered the question, “To what extent do scholars publish in non-English languages?” This study addresses that question, limiting its scope to Vietnamese scholars.Methods: We reviewed 833 non-English documents authored by at least one scholar from Vietnam between 1960 and 2021, exploring aspects such as the language of the publication, the year of publication, the document type, number of document citations, the most prolific and most cited authors, and the primary research themes.Results: Among non-English languages, French, Russian, and Chinese were the three most often selected by Vietnamese scholars for their publications. The year 2015 was a pivotal year when non-English publications from Vietnam significantly increased. Journal articles were the most common type of document, and the most frequent subject areas were medicine, agricultural and biological sciences, engineering, energy, and environmental science.Conclusion: Although English is the primary language of science, the number of non-English documents by Vietnamese researchers has been increasing. This suggests that collaborative work between Vietnamese researchers and foreign researchers has also increased.

Efforts in the Formation and Development of Nuclear Medicine in Vietnam

Trong Khoa Mai,Cam Phuong Pham,Tien Cong Bui,Hai Binh Tran,Van Thai Pham,Manh Phuong Dao,Dinh Ha Tran 대한핵의학회 2019 핵의학 분자영상 Vol.53 No.2

The foundations of nuclear medicine in Vietnam were established from 1970. Until now, after 48 years of development, in Vietnam, we have some basic equipment including 31 SPECT, 4 SPECT/CT machines, 11 PET/CT scanners, five cyclotrons, and one nuclear reactor.Many nuclearmedicine techniques in diagnosis and treatment have been routinely performed at provincial and central level health facilities such as tumor scintigraphy, thyroid scintigraphy, bone scintigraphy, kidney scintigraphy, cardiac scintigraphy, and radio-isotope therapy with I-131 and P-32. Selective internal radiation therapy with Y-90 microsphere and I-125 radioactive seed implantation has been also successfully applied in some big hospitals. However, there are still many difficulties for Vietnam as the lack of new widely used radioisotopes such as Ga-67, Cu-64, Samarium-153, and Lutetium-177 and the lack of nuclear medicine specialists. In the future, we are putting our efforts on the applications of new isotopes in diagnosis and treatment of cancers (theranostic) like Ga-68-DOTATATE, Lutetium-177-DOTATATE, Ga-68-PSMA, and Lutetium-177-PSMA, equipping modern nuclear medicine diagnostic tools, strengthening the human resources training in nuclear medicine. At the same time, we are trying our best to strengthen the cooperation with international nuclear medicine societies in over the world.