Structural and Magnetic Phase Transitions of Shape-Memory Ni50Mn25+xGa25-x Alloys with Excess Mn

Nguyen Phu Thuy,Ngo Van Nong,Yeong Der Yao 한국물리학회 2008 THE JOURNAL OF THE KOREAN PHYSICAL SOCIETY Vol.52 No.5

The Mn-excess Ni50Mn25+xGa25-x alloys with 1 < x < 7 were developed to investigate struc- tural transitions and magnetic properties. The martensitic transformation temperature (TM) for the structural transformation from tetragonal to cubic was clearly observed from magnetization, electrical resistivity and X-ray diraction studies as a function of temperature for temperatures be- low 400 K. The TM value increased roughly from 260 K to 355 K with increasing Mn concentration and TM showed an abrupt change at the composition x = 5. For the structural transition, the Curie temperature (TC) decreased slightly from 380 K and was insensitive to variations on the Mn/Ga ratio. During the heating and the cooling processes, the samples showed a temperature hysteresis at and below TM. A magnetic-eld-induced strain (MFIS) of about 0.2 % at an applied magnetic ld of 4.2 kOe was derived by using the martensitic transition temperature for polycrystalline samples. The Mn-excess Ni50Mn25+xGa25-x alloys with 1 < x < 7 were developed to investigate struc- tural transitions and magnetic properties. The martensitic transformation temperature (TM) for the structural transformation from tetragonal to cubic was clearly observed from magnetization, electrical resistivity and X-ray diraction studies as a function of temperature for temperatures be- low 400 K. The TM value increased roughly from 260 K to 355 K with increasing Mn concentration and TM showed an abrupt change at the composition x = 5. For the structural transition, the Curie temperature (TC) decreased slightly from 380 K and was insensitive to variations on the Mn/Ga ratio. During the heating and the cooling processes, the samples showed a temperature hysteresis at and below TM. A magnetic-eld-induced strain (MFIS) of about 0.2 % at an applied magnetic ld of 4.2 kOe was derived by using the martensitic transition temperature for polycrystalline samples.

Giant Parallel and Perpendicular Exchange Biases in MnPd/Co Bilayers

Nguyen Thanh Nam,Nguyen Phu Thuy,Nguyen Anh Tuan,Nguyen Nguyen Phuoc,Takao Suzuki 한국자기학회 2007 한국자기학회 학술연구발표회 논문개요집 Vol.- No.-

Invasive Non-typhoidal <i>Salmonella</i> Infections in Asia: Clinical Observations, Disease Outcome and Dominant Serovars from an Infectious Disease Hospital in Vietnam

Phu Huong Lan, Nguyen,Le Thi Phuong, Tu,Nguyen Huu, Hien,Thuy, Le,Mather, Alison E.,Park, Se Eun,Marks, Florian,Thwaites, Guy E.,Van Vinh Chau, Nguyen,Thompson, Corinne N.,Baker, Stephen Public Library of Science 2016 PLoS neglected tropical diseases Vol.10 No.8

<▼1><P>Invasive non-typhoidal <I>Salmonella</I> (iNTS) infections are now a well-described cause of morbidity and mortality in children and HIV-infected adults in sub-Saharan Africa. In contrast, the epidemiology and clinical manifestations of iNTS disease in Asia are not well documented. We retrospectively identified >100 cases of iNTS infections in an infectious disease hospital in Southern Vietnam between 2008 and 2013. Clinical records were accessed to evaluate demographic and clinical factors associated with iNTS infection and to identify risk factors associated with death. Multi-locus sequence typing and antimicrobial susceptibility testing was performed on all organisms. Of 102 iNTS patients, 71% were HIV-infected, >90% were adults, 71% were male and 33% reported intravenous drug use. Twenty-six/92 (28%) patients with a known outcome died; HIV infection was significantly associated with death (<I>p</I> = 0.039). <I>S</I>. Enteritidis (Sequence Types (ST)11) (48%, 43/89) and <I>S</I>. Typhimurium (ST19, 34 and 1544) (26%, 23/89) were the most commonly identified serovars; <I>S</I>. Typhimurium was significantly more common in HIV-infected individuals (<I>p</I> = 0.003). Isolates from HIV-infected patients were more likely to exhibit reduced susceptibility against trimethoprim-sulfamethoxazole than HIV-negative patients (<I>p</I> = 0.037). We conclude that iNTS disease is a severe infection in Vietnam with a high mortality rate. As in sub-Saharan Africa, HIV infection was a risk factor for death, with the majority of the burden in this population found in HIV-infected adult men.</P></▼1><▼2><P><B>Author Summary</B></P><P>Invasive non-typhoidal <I>Salmonella</I> (iNTS) infections occur when <I>Salmonella</I> bacteria, which normally cause diarrhea, enter the bloodstream and spread through the body. Invasive NTS infections have become a common cause of infection and death in children with malaria and adults with HIV in sub-Saharan Africa. However, it is unknown whether iNTS is as common or as severe outside sub-Saharan Africa. We evaluated over 100 iNTS cases from an infectious disease hospital in southern Vietnam admitted between 2008–2013. We used hospital records to determine the clinical features of iNTS disease and to identify risk factors associated with death and performed typing of the isolated organisms. The majority of patients were HIV positive (72/102, 71%), >90% of patients were adults, 71% were male and 33% reported intravenous drug use. The mortality rate of iNTS patients was 28% (26/92), and HIV infection was a significant risk factor for fatal outcome (<I>p</I> = 0.039). The serovars most commonly identified were <I>S</I>. Enteritidis and <I>S</I>. Typhimurium; <I>S</I>. Typhimurium was found more frequently in HIV-positive individuals (<I>p</I> = 0.003). We report that iNTS disease is a severe infection in Vietnam with a high mortality rate. Similar to sub-Saharan Africa, HIV infection was a strong risk factor for death.</P></▼2>

Exploring Critical Risk Factors of Office Building Projects

NGUYEN, Phong Thanh,PHAM, Cuong Phu,PHAN, Phuong Thanh,VU, Ngoc Bich,DUONG, My Tien Ha,NGUYEN, Quyen Le Hoang Thuy To Korea Distribution Science Association 2021 The Journal of Asian Finance, Economics and Busine Vol.8 No.2

Risks and uncertainty are unavoidable problems in management of projects. Therefore, project managers should not only prevent risks, but also have to respond and manage them. Risk management has become a critical interest subject in the construction industry for both practitioners and researchers. This paper presents critical risk factors of office building projects in the construction phase in Ho Chi Minh City, Vietnam. Data was collected through a questionnaire survey based on the likelihood and consequence level of risk factors. These factors fell into five groups: (i) financial risk factors; (ii) management risk factors; (iii) schedule risk factors; (iv) construction risk factors; and (v) environment risk factors. The research results showed that critical factors affecting office building projects are natural (i.e., prolonged rain, storms, climate effects) and human-made issues (i.e., soil instability, safety behaviors, owner's design change) and the schedule-related risk factors contributed to the most significant risks for office buildings projects in the construction phase in Ho Chi Minh City. They give construction management and project management practitioners a new perspective on risks and risk management of office buildings projects in Ho Chi Minh City and are proactive in the awareness, response, and management of risk factors comprehensively.

A Novel Injectable pH–Temperature Sensitive Hydrogel Containing Chitosan–Insulin Electrosprayed Nanosphere Composite for an Insulin Delivery System in Type I Diabetes Treatment

Thuy An Trinh,Thai Minh Duy Le,Hoang Gia Vinh Ho,Thi Cam Thach To,Vu Viet Linh Nguyen,Dai Phu Huynh,Doo Sung Lee 한국고분자학회 2021 한국고분자학회 학술대회 연구논문 초록집 Vol.46 No.1

Faculty of Materials Technology, Ho Chi Minh University of Technology (HCMUT)/Vietnam National University Ho Chi Minh City; ¹School of Chemical Engineering and Theragnostic Macromolecules Research Center, Sungkyunkwan University; ²Vietnam National University Ho Chi Minh City/National Key Laboratory of Polymer and Composite Materials, Ho Chi Minh University of Technology, Vietnam National University; ³Faculty of Materials Technology, Ho Chi Minh University of Technology (HCMUT)/ Vietnam National University Ho Chi Minh City/Research Center for Polymeric Materials, Ho Chi Minh University of Technology, Vietnam National University In this research, a novel insulin composite delivery system was prepared and characterized. Insulin drug was loading in chitoshan nanospheres using electrospraying method, a pH- and temperature-sensitive biodegradable hydrogel, which is an oligomer serine-poly(lactide)-poly(ethylene glycol)-poly (lactide)-oligomer serine (OS-PLA-PEG-PLA-OS) pentablock copolymer was used as a matrix to containing chitosan–insulin electro sprayed nanospheres (CIN). The properties of the OS-PLA-PEG-PLA-OS pentablock copolymer and the chitosan–insulin nanoparticles such as sol-gel transition, degradation in vitro and in vivo were characterized. The results showed that the chitosan–insulin nanospheres uniformly distributed in the matrix had a reinforcing effect on the mechanical properties and prolonged the degradation time of the hydrogel depot under body conditions. In addition, the cytotoxicity experiment results indicate that the composite could be used as a biomaterial for drug delivery system. The composite solutions accommodating different concentrations of the chitosan–insulin nanospheres were subcutaneously injected into induced diabetic BALB/c mice to study the in vivo insulin-release profile. The result showed that insulin concentrations in blood plasma were maintained at a steady-state level. Furthermore, the bio-properties of the insulin were retained and it showed a blood glucose level reducing effect for more than 60 hours after injection to a streptozotocin (STZ)-induced diabetic mouse model. The results suggested that this injectable pH–temperature sensitive hydrogel containing chitosan– insulin electro sprayed nanosphere composites has promising potential applications for type 1 diabetes treatment.

Bias–stress-induced threshold voltage shift dependence of negative charge trapping in the amorphous indium tin zinc oxide thin-film transistors

Nguyen, Cam Phu Thi,Trinh, Thanh Thuy,Dao, Vinh Ai,Raja, Jayapal,Jang, Kyungsoo,Le, Tuan Anh Huy,Iftiquar, S M,Yi, Junsin Institute of Physics 2013 Semiconductor science and technology Vol.28 No.10

<P>Indium tin zinc oxide (ITZO)-based thin-film transistors (TFTs) were fabricated by dc magnetron sputtering in Ar + O<SUB>2</SUB> reactive gas, at room temperature. We present the effect of post-deposition annealing of ITZO thin films on the oxygen vacancies and on the characteristics of TFT devices. When the annealing temperature was increased from room temperature to 350 °C, the resistivity of ITZO film increased from 2.05 × 10<SUP>1</SUP> to 2.60 × 10<SUP>3</SUP> Ω cm and the interface trap density (<I>N</I><SUB>t</SUB>) of the TFTs reduced from 3.18 × 10<SUP>13</SUP> to 4.83 × 10<SUP>11</SUP> cm<SUP>−2</SUP>. The TFT with the ITZO film which was annealed at 350 °C showed a very small shift in turn-on voltage, even after applying positive bias stress of +12 V for 10<SUP>4</SUP> s. The current–voltage characteristics of 350 °C annealing temperature sample indicated that these TFTs were in an enhanced mode of transistor operation with a high on-to-off current ratio of ∼1.26 × 10<SUP>6</SUP>, high field-effect mobility of 14.17 cm<SUP>2</SUP> V<SUP>−1</SUP> s<SUP>−1</SUP>, and low subthreshold slope of 1.23 V/dec. The trapping time reduced from 3720 to 1546 s as the annealing temperature increased from room temperature to 350 °C. These results suggest that thermal annealing played an important role in reducing defects as well as improvement in stability of the TFTs.</P>

Fabrication of ZnO nanorods for gas sensing applications using hydrothermal method.

Nguyen, Cam Phu Thi,La, Phan Phuong Ha,Trinh, Thanh Thuy,Le, Tuan Anh Huy,Bong, Sungjae,Jang, Kyungsoo,Ahn, Shihyun,Yi, Junsin American Scientific Publishers 2014 Journal of Nanoscience and Nanotechnology Vol.14 No.8

<P>We showed well-aligned zinc oxide (ZnO) nanorod arrays synthesized using hydrothermal method at atmospheric pressure. The influence of fabrication conditions such as Zn2+/hexamethylentriamin concentration ratio, and growth temperature on the formation of ZnO nanorods was investigated. Scanning Electron Microscope (SEM) images and X-ray Diffraction (XRD) analysis were used to confirm the single crystal of ZnO nanorods, which showed wurtzite structure with growth direction of [0001] (the c-axis). Photoluminescence (PL) measurements of ZnO nanorods revealed an intense ultraviolet peak at 388.5 nm (3.19 eV) at room temperature. The results showed that the ZnO seed layers had strong influence on the growth of vertically aligned ZnO nanorods. The gas sensor based on ZnO nanorod arrays had the most selectivity with n-butanol gas (within 2 surveyed gas: ethanol and n-butanol) and showed a higher sensitivity of 222, fast response time of 15 seconds, recovery time of 110 seconds and lower operating temperature of 200-250 C than the sensor based on the ZnO film in the same detecting conditions.</P>

Risk Factors Affecting Equipment Management in Construction Firms

Cuong Phu PHAM,Phong Thanh NGUYEN,Phuong Thanh PHAN,Quyen Le Hoang Thuy To NGUYEN,Loan Phuc LE,My Tien Ha DUONG 한국유통과학회 2020 The Journal of Asian Finance, Economics and Busine Vol.7 No.11

Mechanization and automation constitute an essential stage in the production and operation of any company, as one of the determinants of increase in labor productivity and decrease in product price, while significantly contributing to shortening of the lead time. Businesses are, therefore, able to quickly put projects into operation, improving economic efficiency, quality, and aesthetics, which speeds up the national economic growth. For the construction industry to be the most effective, modern construction equipment is a necessity. It is one of the five main resources of a construction project. Thus, effective construction equipment management contributes to the success of a project and benefits the relevant construction companies economically. This paper presents the critical risk factors affecting equipment management and proposes suitable solutions. The questionnaire-based survey with experienced experts in the construction sector on the management of the likelihood and consequence of risk factors revealed thirty-two risks for equipment management in construction companies. These factors fell into six groups: (i) site organization-related risks; (ii) management-related risks; (iii) owner-related risks; (iv) supplier-related risks; (v) legal risks, and (vi) site condition-related and external risks. The results showed that management-related factors contributed to the most significant risks and problems for equipment management in construction companies.

Investigating InSnZnO as an active layer for non-volatile memory devices and increasing memory window by utilizing Silicon-rich SiO<SUB>x</SUB> for charge storage layer

Heejun PARK,Kyungsoo JANG,Thuy THANH,Cam Phu THI NGUYEN,Sojin LEE,Junsin YI 한국진공학회 2016 한국진공학회 학술발표회초록집 Vol.2016 No.8

The Impact of Consumer Ethnocentrism on Purchase Intention: An Empirical Study from Vietnam

Thanh Ngoc Dan NGUYEN,Phuong Nhu DANG,Phu Hoang TRAN,Trang Thi Thuy NGUYEN 한국유통과학회 2022 The Journal of Asian Finance, Economics and Busine Vol.9 No.2

Ethnocentrism in users plays an important role in predicting user behavior when deciding between imported and domestic goods. The purpose of this study is to look into the influence of ethnocentrism in customer behavior on brand image, perceived value, perceived quality, brand trust, and brand buy intention. Vietnamese customers prefer homegrown brands. The moderate role of consumer ethnocentrism in the conceptual framework emphasizes the country origin of the product is the most important factor. It also demonstrates how the intention of Vietnamese consumers to buy domestic brands is substantially influenced. To test the hypothesis, this article used a quantitative technique utilizing PLS-SEM software. With 917 samples, the study used the quota sampling approach to collect data from students at 10 universities in Ho Chi Minh City. The data suggest that all players have a positive association and that consumer ethnocentrism has a moderate impact in the Vietnamese brand context. Following that, suggestions are made to help Vietnamese firms create and retain their brands in the face of severe competition from global brands in the domestic market. To increase consumer intent in purchasing behavior, the Vietnamese local company needs to establish a strong brand.