SVPWM Strategies for Three-level T-type Neutral-point-clamped Indirect Matrix Converter

Tuyen, Nguyen Dinh,Phuong, Le Minh,Lee, Hong-Hee The Korean Institute of Power Electronics 2019 JOURNAL OF POWER ELECTRONICS Vol.19 No.4

In this paper, the three-level T-type neutral-point-clamped indirect matrix converter topology and the relative space vector modulation methods are introduced to improve the voltage transfer ratio and output voltage performance. The presented converter topology is based on combinations of cascaded-rectifier and three-level T-type neutral-point-clamp inverter. It can overcome the limitation of voltage transfer ratio of the conventional matrix converter and the high voltage rating of power switches of conventional matrix converter. Two SVPWM strategies for proposed converter are described in this paper to achieve the advantages features such as: sinusoidal input/output currents and three-level output voltage waveforms. Results from Psim 9.0 software simulation are provided to confirm the theoretical analysis. Hence, a laboratory prototype was implemented, and the experimental results are shown to validate the simulation results and to verify the effectiveness of the proposed topology and modulation strategies.

A comparison in human milk oligosaccharides from Korea, China and Vietnam

Tuyen Thi My Nguyen,NariSeo,YongkiKim,JiAJung,JaehanKim 한국당과학회 2018 한국당과학회 학술대회 Vol.2018 No.01

Among the animal, human uniquely contains high amount and diverse structure of soluble oligosaccharides in milk. The multiple functions for infant of human milk oligosaccharides (HMOs) have been well discussed, particularly sialic acid and fucose containing oligosaccharide. The structure and composition of HMOs structure were diverse among different mothers or breastfeeding period of a given woman as well, and nutritional conditions. The geographical origin of mothers is one of the factors that influence on the HMOs diversity. Hence, we aim to profile HMOs from mothers in Korea, China and Vietnam in the relation to their nutritional status to provide a comprehensive understanding about HMOs from maternal in these countries. The results show that oligosaccharide composition of human milk varied among countries. HMOs from Korea and China were almost similar in term of degree of polymerization (DP) whereas Vietnam HMOs has lower DP3 but high in DP4 and DP5. The ratio of non-secretor mothers that were unable to produce α-1, 2-fucosylated glycans in their secretions, following by Vietnam and lowest in Korea population. The fucosylated, and sialylated HMOs were 62-67%, 4-6% in China and Korea milk respectively while 50% and 9.2% in Vietnam maternal milk. These observed proportion were different from earlier studies that may due to the difference in geographical origin of mothers. Elucidating molecular structure of HMOs provides an important opportunities for improving diet and health care for the neonate in specific region.

Two and Three Dimensional Numerical Simulations of Beetle Hindwing in Forward Flight

Tuyen Quang Le,Tien Van Truong,Soo Hyung Park,Jin Hwan Ko,Hoon Cheol Park,Doyoung Byun 대한기계학회 2011 대한기계학회 춘추학술대회 Vol.2011 No.10

Carrier Phase-Shift PWM to Reduce Common-Mode Voltage for Three-Level T-Type NPC Inverters

Tuyen D. Nguyen,Dzung Quoc Phan,Dat Ngoc Dao,Hong-Hee Lee 전력전자학회 2014 JOURNAL OF POWER ELECTRONICS Vol.14 No.6

Common-mode voltage (CMV) causes overvoltage stress to winding insulation and damages AC motors. CMV with high dv/dt causes leakage currents, which create noise problems for equipment installed near the converter. This study proposes a new pulse-width modulation (PWM) strategy for three-level T-type NPC inverters. This strategy substantially eliminates CMV. The principle for selecting suitable triangle carrier signals for the three-level T-type NPC is described. The proposed method can mitigate the peak value of CMV by 50% compared with the phase disposition pulse-width modulation method. Furthermore, the proposed method exhibits better harmonic spectrum and lower root mean square value for the CMV than those of the reduced-CMV method on the basis of the phase opposition disposition PWM scheme with modulation index higher than 0.5. The proposed modulation can easily be implemented using software without any additional hardware modifications. Both simulation and experimental results demonstrate that the proposed carrier phase-shift PWM method has good output waveform performance and reduces CMV.

A New Comprehensive Short-form Health Literacy Survey Tool for Patients in General

Tuyen Van Duong,Peter WuShou Chang,Shih-Hsien Yang,Ming-Chu Chen,Wei-Ting Chao,Tara Chen,Priscilla Chiao,Hsiao-Ling Huang 한국간호과학회 2017 Asian Nursing Research Vol.11 No.1

Purpose: To validate a conceptual short-form health literacy 12 items questionnaire (HL-SF12) in patient populations. Methods: A cross-sectional study was conducted via a convenient sample of 403 patients from three departments of a community general hospital in the northern Taiwan. Patients’ health literacy was assessed with a validated HL-SF12, derived from the full scale, the European Health Literacy Survey Questionnaire (HLS-EU-Q), as well as a single-item from Chew’s Set of Brief Health Literacy Question. A reference population in Northern Taiwan (n = 928) via the HLS-EU-Q in 2013e2014 was used as a reference to compare the health literacy between that of the general public and the patients. Data was analyzed by confirmatory factor analysis (CFA), internal consistency analysis, correlation analysis, and linear regression models. Results: Patients’ health literacy assessed with the HL-SF12 was shown with high internal consistency (Cronbach a = .87), and moderately correlated with the single-item from Chew's Set of Brief Health Literacy Question, with satisfactory item-scale convergent validity (item-scale correlation> .40), without floor/ceiling effect, and with satisfactory goodness of fit indices of the three-factor construct model for most of the patients. Their health literacy was significantly positively associated with female gender, higher income, and more often watching health-related TV programs. On the other hands, patients were reported with significantly higher healthcare health literacy than the general public, but not in general health literacy, disease prevention health literacy, or health promotion health literacy. Conclusion: The comprehensive HL-SF12 was a valid and easy to use tool for assessing patients’ health literacy in the hospitals to facilitate healthcare providers in enhancing patients’ health literacy and healthcare qualities.

Flow-driven rotor simulation of vertical axis tidal turbines: A comparison of helical and straight blades

Tuyen Quang Le,이광수,박진순,고진환 대한조선학회 2014 International Journal of Naval Architecture and Oc Vol.6 No.2

In this study, flow-driven rotor simulations with a given load are conducted to analyze the operational characteristics of a vertical-axis Darrieus turbine, specifically its self-starting capability and fluctuations in its torque as well as the RPM. These characteristics are typically observed in experiments, though they cannot be acquired in simula-tions with a given tip speed ratio (TSR). First, it is shown that a flow-driven rotor simulation with a two-dimensional (2D) turbine model obtains power coefficients with curves similar to those obtained in a simulation with a given TSR. 3D flow-driven rotor simulations with an optimal geometry then show that a helical-bladed turbine has the following prominent advantages over a straight-bladed turbine of the same size: an improvement of its self-starting capabilities and reduced fluctuations in its torque and RPM curves as well as an increase in its power coefficient from 33% to 42%. Therefore, it is clear that a flow-driven rotor simulation provides more information for the design of a Darrieus turbine than a simula-tion with a given TSR before experiments.

Synthesis and Antiinflammatory Activity of 1,5-Diarylimidazoles

Tuyen Truong Ngoc,Sin Kwang-Seog,Kim Hyun Pyo,Park Haeil The Pharmaceutical Society of Korea 2005 Archives of Pharmacal Research Vol.28 No.9

A number of 1,5-diarylimidazoles has been synthesized and evaluated for their inhibitory activities of COX-2 catalyzed $PGE_2$ production. 1,5-Diarylimidazoles were obtained from imimes and p-toluenesulfonylmethyl cyanide (TosMIC). Imines were prepared from commercially available amines and aldehydes. Among the compounds tested, 1-(2,4-difluorophenyl)-5-(4­methylsulfonylphenyl)imidazole (2r) showed strong inhibitory activity, however, most diarylimidazoles exhibited little to low inhibitory activities against COX-2 catalyzed $PGE_2$ production.

A proposed biosynthesis pathway of minor ginsenosides from red ginseng residue

Tuyen Thi My Nguyen,Dong Hyun Jang,Sang ManYoun,Jong Tae Park,Jae Han Kim 한국당과학회 2018 한국당과학회 학술대회 Vol.2018 No.07

Minor ginsenosides, those have low content in white or red ginseng, are proved to have strong pharmaceutical activities in literature. There are many minor ginsenosides can be formed during transformation in various pathways. In which, the biotransformation pathway of Rb2→Rd→F2→C-K or Rc, Rbl, Rb2→Rg3→Rh2 by using various bacteria, yeast, and fungus was well-known. However, the other pathway that converts Rb2→C-0→C-Y→C-K or Rc→C-Mc→C-K were seldom occurred. In this study, utilization of red ginseng residue (RGR), a byproduct of red ginseng extraction, for minor ginsenoside production by using enzyme cellulose, hemicellulase, and lactic acid fermentation was performed. Biotransformation of ginsenosides was analyzed by UPLC-UV /EIS-QQQ mass spectrometry. During enzymatic reaction and lactic acid fermentation, the relative abundance of ginsenoside Rbl, Rg3, Rb2, and Rc were decreased while a significant increase in rare ginsenoside F2, Rh2 , C-K, C-0, and C-Mc were obtained. Our results suggested that combination of cell wall degrading enzyme and metabolism of lactic acid bacteria (LPlantarium and LLactis) could remove glucosyl moieties from ginsenosides. Particularly, C-0, C-Mc could be obtained during enzymatic treatment and lactic acid fermentation. This method could be applied for production of C-0, C-Mc, and C-K from RGR. For further research, this result may open a new direction toward RGR utilization for minor ginsenosides.

Nitrogen removal performance of anammox process with PVA–SA gel bead crosslinked with sodium sulfate as a biomass carrier

Tuyen, N.V.,Ryu, J.H.,Yae, J.B.,Kim, H.G.,Hong, S.W.,Ahn, D.H. Elsevier 2018 Journal of industrial and engineering chemistry Vol.67 No.-

<P><B>Abstract</B></P> <P>In this study, the result shows that polyvinyl alcohol–sodium alginate (PVA–SA) gel bead crosslinked with sodium sulfate are better among the different methods by comparing the relative mechanical strength, mechanical strength swelling and expansion coefficient of beads in water. Subsequently, anammox biomass entrapment by PVA–SA gel was introduced into continuous stirred tank reactor (CSTR). After 24 operation days, the nitrogen removal efficiency achieved 60%, while the nitrogen loading rate (NLR) was 0.14kgN/m<SUP>3</SUP>/d and the experiment data indicated that PVA–SA gel bead crosslinked with sodium sulfate can be used to initiate anammox process. Furthermore, it is an alternative for culturing anammox in a long-term operation.</P> <P><B>Graphical abstract</B></P> <P>[DISPLAY OMISSION]</P>

Univector field method-based multi-agent navigation for pursuit problem in obstacle environments

Tuyen, L. P.,Viet, H. H.,An, S. H.,Lee, S. G.,Kim, D. H.,Chung, T. C. Springer Science + Business Media 2017 Journal of Central South University Vol.24 No.4