Structure and Magnetic Properties of Nd45-xCxFe30Co15Al10 Alloys

Nguyen Anh Tuan,Vu Hong Ky,Nguyen Huy Dan,Luu Tien Hung 한국물리학회 2008 THE JOURNAL OF THE KOREAN PHYSICAL SOCIETY Vol.52 No.5

Nd45-xCxFe30Co15Al10 (x = 0, 1, 3, 5 and 7) alloys were prepared by using a copper mold suction casting method. X-ray diraction (XRD) patterns show a trend of increasing crystallinity with increasing C content. In addition, crystallites with dierent shapes and sizes are observed by using scanning electron microscopy (SEM) and high-resolution transmission electron microscopy (HRTEM). Multi-phase properties of the alloys are clearly exhibited on the magnetic measurements. The hysteresis loops of the lower C content alloys (x = 1 and 3) show a single-phase hard magnetic behavior with coercivities of 6.2 kOe while the loops of the higher C content alloys (x = 5 and 7) are supposing a multi-phase property with coercivities up to 7.2 kOe. Two magnetic-phase transitions, depending on the C concentration, appear in the thermomagnetization curves. Addition of C at low content (1 to 3 at.%) can improve the hard magnetic behavior of the Nd-(Fe, Co)-Al alloy. Nd45-xCxFe30Co15Al10 (x = 0, 1, 3, 5 and 7) alloys were prepared by using a copper mold suction casting method. X-ray diraction (XRD) patterns show a trend of increasing crystallinity with increasing C content. In addition, crystallites with dierent shapes and sizes are observed by using scanning electron microscopy (SEM) and high-resolution transmission electron microscopy (HRTEM). Multi-phase properties of the alloys are clearly exhibited on the magnetic measurements. The hysteresis loops of the lower C content alloys (x = 1 and 3) show a single-phase hard magnetic behavior with coercivities of 6.2 kOe while the loops of the higher C content alloys (x = 5 and 7) are supposing a multi-phase property with coercivities up to 7.2 kOe. Two magnetic-phase transitions, depending on the C concentration, appear in the thermomagnetization curves. Addition of C at low content (1 to 3 at.%) can improve the hard magnetic behavior of the Nd-(Fe, Co)-Al alloy.

Detection of pathogenic microorganisms using biosensor based on multi-walled carbon nanotubes dispersed in DNA solution

Nguyen Thi Thuy,Phuong Dinh Tam,Mai Anh Tuan,Anh-Tuan Le,Le Thi Tam,Vu Van Thu,Nguyen Van Hieu,Nguyen Duc Chien 한국물리학회 2012 Current Applied Physics Vol.12 No.6

The present paper introduces a facile and cost-effective route for the direct dispersion of multi-walled carbon nanotubes (MWCNTs) in DNA solution. Their application in detecting Escherichia coli O157:H7using DNA biosensorwas demonstrated. The dispersion state of theMWCNTswas characterized via UVeVis spectroscopy, transmission electron microscopy, and field emission scanning electron microscopy. The interaction between DNA sequence and the MWCNTs was investigated using Raman spectroscopy and Fourier transform infrared spectroscopy. As-obtainedMWCNT solutionwas used in the preparation of DNA sensor. Results revealed that the developed DNA sensor can detect a DNA target as low as 1 nM in a buffer solution. The sensitivity of the DNA sensor reached approximately 0.19 nM/mV. The effect of dispersion parameters, including pH values, DNA concentration, ion strength, and sonication time, on sensor response was also studied. TheDNA sensor can respondwell to 120 min of sonication time, a pH value of 9, and 20 mM of DNA sequence concentration. The results of the present study showed a potential application of the DNA sensor in the detection of Escherichia coli O157:H7.

An improvement of real-time polymerase chain reaction system based on probe modification is required for accurate detection of African swine fever virus in clinical samples in Vietnam

Tran Ha Thi Thanh,Dang Anh Kieu,Ly Duc Viet,Vu Hao Thi,Hoang Tuan Van,Nguyen Chinh Thi,Chu Nhu Thi,Nguyen Vinh The,Nguyen Huyen Thi,Truong Anh Duc,Pham Ngoc Thi,Dang Hoang Vu 아세아·태평양축산학회 2020 Animal Bioscience Vol.33 No.10

Objective: The rapid and reliable detection of the African swine fever virus (ASFV) plays an important role in emergency control and preventive measures of ASF. Some methods have been recommended by FAO/OIE to detect ASFV in clinical samples, including real-time polymerase chain reaction (PCR). However, mismatches in primer and probe binding regions may cause a false-negative result. Here, a slight modification in probe sequence has been conducted to improve the qualification of real-time PCR based on World Organization for Animal Health (OIE) protocol for accurate detection of ASFV in field samples in Vietnam. Methods: Seven positive confirmed samples (four samples have no mismatch, and three samples contained one mutation in probe binding sites) were used to establish novel real-time PCR with slightly modified probe (Y = C or T) in comparison with original probe recommended by OIE. Results: Both real-time PCRs using the OIE-recommended probe and novel modified probe can detect ASFV in clinical samples without mismatch in probe binding site. A high correlation of cycle quantification (Cq) values was observed in which Cq values obtained from both probes arranged from 22 to 25, suggesting that modified probe sequence does not impede the qualification of real-time PCR to detect ASFV in clinical samples. However, the samples with one mutation in probe binding sites were ASFV negative with OIE recommended probe but positive with our modified probe (Cq value ranked between 33.12-35.78). Conclusion: We demonstrated for the first time that a mismatch in probe binding regions caused a false negative result by OIE recommended real-time PCR, and a slightly modified probe is required to enhance the sensitivity and obtain an ASF accurate diagnosis in field samples in Vietnam.

Tobacco Control Policies in Vietnam: Review on MPOWER Implementation Progress and Challenges

Hoang, Van Minh,Tran, Thu Ngan,Vu, Quynh Mai,Nguyen, Thi Tuyet My,Le, Hong Chung,Vu, Duy Kien,Tran, Tuan Anh,Nguyen, Bao Ngoc,Vu, Van Giap,Nguyen, Manh Cuong,Pham, Duc Manh,Kim, Bao Giang Asian Pacific Journal of Cancer Prevention 2016 Asian Pacific journal of cancer prevention Vol.17 No.no.sup1

In Vietnam, the WHO Framework Convention on Tobacco Control (WHO FCTC) took effect in March 2005 while MPOWER has been implemented since 2008. This paper describes the progress and challenges of implementation of the MPOWER package in Vietnam. We can report that, in term of monitoring, Vietnam is very active in the Global Tobacco Surveillance System, completing two rounds of the Global Adult Tobacco Survey (GATS) and three rounds of the Global Youth Tobacco Survey (GYTS). To protect people from tobacco smoke, Vietnam has issued and enforced a law requiring comprehensive smoking bans at workplaces and public places since 2013. Tobacco advertising and promotion are also prohibited with the exception of points of sale displays of tobacco products. Violations come in the form of promotion girls, corporate social responsibility activities from tobacco manufacturers and packages displayed by retail vendors. Vietnam is one of the 77 countries that require pictorial health warnings to be printed on cigarette packages to warn about the danger of tobacco and the warnings have been implemented effectively. Cigarette tax is 70% of factory price which is equal to less than 45% of retail price and much lower than the recommendation of WHO. However, Vietnam is one of the very few countries that require manufacturers and importers to make "compulsory contributions" at 1-2% of the factory price of cigarettes sold in Vietnam for the establishment of a Tobacco Control Fund (TCF). The TCF is being operated well. In 2015, 67 units of 63 provinces/cities, 22 ministries and political-social organizations and 6 hospitals received funding from TCF to implement a wide range of tobacco control activities. Cessation services have been starting with a a toll-free quit-line but need to be further strengthened. In conclusion, Vietnam has constantly put efforts into the tobacco control field with high commitment from the government, scientists and activists. Though several remarkable achievements have been gained, many challenges remain. To overcome those challenges, implementation strategies that take into account the contextual factors and social determinants of tobacco use in Vietnam are needed.

Billroth-II Modified with Antiperistaltic Hinged Afferent Loop versus Roux-en-Y Reconstruction after Laparoscopic Distal Gastrectomy: A Propensity Score-Matched Analysis

Duy Long Vo,Quang Thong Dang,Quang Dat Tran,Viet Hai Nguyen,Le Minh Quoc Ho,Thuy Nguyen Doan,Anh Minh Tran,Vu Tuan Anh Nguyen,Lam Vuong Nguyen,Hoang Bac Nguyen 대한외과학회 2022 대한외과학회 학술대회 초록집 Vol.2022 No.11

Evaluation of grinding wheel wear in wet profile grinding for the groove of the ball bearing’s inner ring by pneumatic probes

Vu Toan Thang,Nguyen Anh Tuan,Nguyen Viet Tiep 대한기계학회 2018 JOURNAL OF MECHANICAL SCIENCE AND TECHNOLOGY Vol.32 No.3

Wear is one of the most influential factors in profile grinding. The measuring of grinding wheel wear is costly and time consuming. We introduce a new online wear measuring method in a wet profile grinding for the inner ring groove of ball bearing. The advantage of this method is the reduction of electromagnetic influence of workpiece as well as the impact of grinding debris and cutting lubricant. Two pneumatic gauging probes are positioned at two different locations with the biggest gap in the wear value on the curved edge surface of the grind stone. When the compressed air flow is blown onto the working surface of the grinding wheel, the back pressure in the measuring chamber corresponding to the gap between the probe and the working surface of the grinding wheel can be measured. Therefore, the radial wear value of grinding wheel can be determined. Based on theoretical calculations and the establishment of its dynamic characteristic curve, it is demonstrated that the first probe measuring wear at the top of the curved edge surface of the grinding wheel with the parameters of the probe d 1 = 0.85; d 2 = 1.5; P = 4 Bar has a measurement range of 200 µm, a maximum speed ratio of 0.01 Bar/µm. The second probe used to capture wear at the margin of the curved edge surface of the grinding stone with the parameters of the probe d 1 = 0.65; d 2 = 1.6; P = 4 Bar has a measurement range of 140 µm, a maximum speed ratio of 0.03 Bar/µm. The experimental results show that the grinding wheel wear value varies at different points of the curved edge surface of the grinding wheel. In profile grinding for the inner ring groove of the 6208 ball bearing, the wear value at the edge of the curved edge surface of the grinding wheel is usually bigger than that at the top of the curved edge surface of the grinding wheel.

Flapping flight in the wake of a leading insect

Anh Tuan Nguyen,Thanh Dong Pham,Quoc Tru Vu 대한기계학회 2019 JOURNAL OF MECHANICAL SCIENCE AND TECHNOLOGY Vol.33 No.7

This study explores the wake effects of an upstream leading insect on the flight performance of a following one. The potential-flow based aerodynamic model, which combines the unsteady panel and unsteady vortex-lattice methods, is used to compute aerodynamic loads and simulate wake structures. The accuracy of the current aerodynamic model was confirmed in this study. The paper shows that the following insect does not cause any noticeable impact on the leading insect aerodynamics, while unfavorable effects due to the presence of the leading insect were found on the following counterpart. Nonetheless, by choosing a proper wing kinematic phase, the following insect may absorb the energy of the leading insect’s trailing wake, and therefore mitigate these negative effects. The variations of the required mechanical power of the following insect against the wing kinematic phase difference were shown to be related to the travel of the leading insect’s downstroke starting vortex.

The branching patterns and termination points of the facial artery: a cadaveric anatomical study

Vu Hoang Nguyen,Lin Cheng-Kuan,Tuan Anh Nguyen,Trang Huu Ngoc Thao Cai 대한두개안면성형외과학회 2024 Archives of Craniofacial Surgery Vol.25 No.2

Background: The facial artery is an important blood vessel responsible for supplying the anterior face. Understanding the branching patterns of the facial artery plays a crucial role in various medical specialties such as plastic surgery, dermatology, and oncology. This knowledge contributes to improving the success rate of facial reconstruction and aesthetic procedures. However, debate continues regarding the classification of facial artery branching patterns in the existing literature. Methods: We conducted a comprehensive anatomical study, in which we dissected 102 facial arteries from 52 embalmed and formaldehyde-fixed Vietnamese cadavers at the Anatomy Department, University of Medicine and Pharmacy, Ho Chi Minh City, Vietnam. Results: Our investigation revealed eight distinct termination points and identified 35 combinations of branching patterns, including seven arterial branching patterns. These termination points included the inferior labial artery, superior labial artery, inferior alar artery, lateral nasal artery, angular artery typical, angular artery running along the lower border of the orbicularis oculi muscle, forehead branch, duplex, and short course (hypoplastic). Notably, the branching patterns of the facial artery displayed marked asymmetry between the left and right sides within the same cadaver. Conclusion: The considerable variation observed in the branching pattern and termination points of the facial artery makes it challenging to establish a definitive classification system for this vessel. Therefore, it is imperative to develop an anatomical map summarizing the major measurements and geometric features of the facial artery. Surgeons and medical professionals involved in facial surgery and procedures must consider the detailed anatomy and relative positioning of the facial artery to minimize the risk of unexpected complications.

The Factors Affecting Corporate Income Tax Non-Compliance: A Case Study in Vietnam

NGUYEN, Loan Thi,NGUYEN, Anh Hong Viet,LE, Hac Dinh,LE, Anh Hoang,TRUONG, Tu Tuan Vu Korea Distribution Science Association 2020 The Journal of Asian Finance, Economics and Busine Vol.7 No.8

In many countries, the Government enacts tax laws in order to manage tax collection and regulate the macro-economy. According to Noor, Jamaludin, Omar, and Aziz (2013), tax non-compliance is a growing concern because of its negative effects on the state budget. The main objectives of this article are to identify the factors affecting corporate income tax non-compliance of enterprises in Ho Chi Minh City in accordance with the current situation of Vietnamese tax administration. We use several research methods, including the exploitation of information and practical experiences from both taxpayers and tax authorities; with Probit regression model on a sample of 187 enterprises that have been inspected or examined by tax authorities in Vietnam during the period from 2013 to 2017.The article identified eight factors affecting corporate income tax (CIT) non-compliance: (1) working capital/total assets; (2) revenue/total assets; (3) total debt/total assets; (4) loss in the previous year; (5) receivables/revenue; (6) the size of enterprises; (7) tax administrative penalties/tax payable; and (8) business field. In particular, the tax non-compliance was studied as a violation of Vietnamese tax laws by enterprises declaring an insufficient amount of CIT payable to the State budget.

Experimental study on thrust and power of flapping-wing system based on rack-pinion mechanism

Nguyen, Tuan Anh,Vu Phan, Hoang,Au, Thi Kim Loan,Park, Hoon Cheol IOP Publishing 2016 Bioinspiration & biomimetics Vol.11 No.4

<P>This experimental study investigates the effect of three parameters: wing aspect ratio (AR), wing offset, and flapping frequency, on thrust generation and power consumption of a flapping-wing system based on a rack-pinion mechanism. The new flapping-wing system is simple but robust, and is able to create a large flapping amplitude. The thrust measured by a load cell reveals that for a given power, the flapping-wing system using a higher wing AR produces larger thrust and higher flapping frequency at the wing offset of 0.15 (c) over bar or 0.20 (c) over bar ((c) over bar is the mean chord) than other wing offsets. Of the three parameters, the flapping frequency plays a more significant role on thrust generation than either the wing AR or the wing offset. Based on the measured thrusts, an empirical equation for thrust prediction is suggested, as a function of wing area, flapping frequency, flapping angle, and wing AR. The difference between the predicted and measured thrusts was less than 7%, which proved that the empirical equation for thrust prediction is reasonable. On average, the measured power consumption to flap the wings shows that 46.5% of the input power is spent to produce aerodynamic forces, 14.0% to overcome inertia force, 9.5% to drive the rack-pinion-based flapping mechanism, and 30.0% is wasted as the power loss of the installed motor. From the power analysis, it is found that the wing with an AR of 2.25 using a wing offset of 0.20 (c) over bar showed the optimal power loading in the flapping-wing system. In addition, the flapping frequency of 25 Hz is recommended as the optimal frequency of the current flapping-wing system for high efficiency, which was 48.3%, using a wing with an AR of 2.25 and a wing offset of 0.20 (c) over bar in the proposed design.</P>