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Highly efficient vanadium redox flow batteries enabled by a trilayer polybenzimidazole membrane assembly

CARBON ENERGY 2024年第7期6卷 191-204页

作者： bui, trung tuyen Shin, Mingyu Rahimi, Mohammad Bentien, Anders Kwon, Yongchai Henkensmeier, Dirk Korea Inst Sci & Technol KIST Hydrogen Fuel Cell Res Ctr Seoul South Korea Univ Sci & Technol KIST Sch Div Energy & Environm Technol Seoul South Korea Korea Univ Grad Sch Energy & Environm Seoul South Korea Korea Inst Sci & Technol KIST Hydrogen Fuel Cell Res Ctr Seoul 02792 South Korea Seoul Natl Univ Sci & Technol Dept Chem & Biomol Engn Seoul South Korea Seoul Natl Univ Sci & Technol Dept Chem & Biomol Engn 232 Gongneung ro Seoul 01811 South Korea Aarhus Univ Dept Biol & Chem Engn Aarhus Denmark

A novel polybenzimidazole (PBI)-based trilayer membrane assembly is developed for application in vanadium redox flow battery (VRFB). The membrane comprises a 1 mu m thin cross-linked poly[2,2'-(p-oxydiphenylene)-5,5'-bibenzimidazole] (OPBI) sandwiched between two 20 mu m thick porous OPBI membranes (p-OPBI) without further lamination steps. The trilayer membrane demonstrates exceptional properties, such as high conductivity and low area-specific resistance (ASR) of 51 mS cm(-1) and 81 m Omega cm(2), respectively. Contact with vanadium electrolyte increases the ASR of trilayer membrane only to 158 m Omega cm(2), while that of Nafion is 193 m Omega cm(2). VO2+ permeability is 2.73 x 10(-9) cm(2) min(-1), about 150 times lower than that of Nafion NR212. In addition, the membrane has high mechanical strength and high chemical stability against VO2+. In VRFB, the combination of low resistance and low vanadium permeability results in excellent performance, revealing high Coulombic efficiency (>99%), high energy efficiency (EE; 90.8% at current density of 80 mA cm(-2)), and long-term durability. The EE is one of the best reported to date.

关键词： polybenzimidazole porous membrane proton conductivity trilayer VRFBs PROTON-EXCHANGE MEMBRANES CONDUCTIVITY PERFORMANCE DEGRADATION STABILITY MECHANISM SOLVENT STORAGE ENERGY

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Flow Visualization of Rhinoceros Beetle （Trypoxylus dichotomus） in Free Flight

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Journal of Bionic Engineering 2012年第3期9卷 304-314页

作者： Tien Van Truong tuyen Quang Le Hieu trung Tran Hoon Cheol Parka Kwang Joon Yoon Doyoung Byun . Department of Aerospace Information Engineering Konkuk University Seoul 143-70 l Republic of Korea 2.Costal Engineering and Ocean Energy Research Department Korea Ocean Research and Development Institute 454 Haeanro Sangrok-gu Ansan 426-744 Republic of Korea Department of Advanced Technology Fusion Konkuk University Seoul 143-701 Republic of Korea Department of Mechanical Engineering Sungkyunkwan University Suwon 440-746 Republic of Korea

Aerodynamic characteristics of the beetle, Trypoxylus dichotomus, which has a pair of elytra （forewings） and flexible hind wings, are investigated. Visualization experiments were conducted for various flight conditions of a beetle, Trypoxylus di- chotomus： free, tethered, hovering, forward and climbing flights. Leading edge, trailing edge and tip vortices on both wings were observed clearly. The leading edge vortex was stable and remained on the top surface of the elytron for a wide interval during the downstroke of free forward flight. Hence, the elytron may have a considerable role in lift force generation of the beetle. In addition, we reveal a suction phenomenon between the gaps of the hind wing and the elytron in upstroke that may improve the positive lift force on the hind wing. We also found the reverse clap-fling mechanism of the T. dichotomus beetle in hovering flight. The hind wings touch together at the beginning of the upstroke. The vortex generation, shedding and interaction give a better understanding of the detailed aerodynamic mechanism of beetle flight.

关键词： beetle smoke wire visualization free flight hovering flight wing interaction elytron effect

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Two- and Three-Dimensional Simulations of Beetle Hind Wing Flapping during Free Forward Flight

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Journal of Bionic Engineering 2013年第3期10卷 316-328页

作者： tuyen Quang Le Tien Van Truong Hieu trung Tran Soo Hyung Park Jin Hwan Ko Hoon Cheol Park Kwang Joon Yoon Doyoung Byun Korea Institute of Ocean Science and Technology PO Box 29 Ansan 425-600 Republic of Korea Department of Aerospace and Information Engineering Konkuk University Seoul Republic of Korea Department of Advanced Technology Fusion Konkuk University Seoul Republic of Korea Department of Mechanical Engineering Sungkyunkwan University Suwon440-746 Republic of Korea

Aerodynamic characteristic of the beetle, Trypoxylus dichotornus, which has a pair of elytra （forewings） and hind wings, is numerically investigated. Based on the experimental results of wing kinematics, two-dimensional （2D） and three-dimensional （3D） computational fluid dynamic simulations were carried out to reveal aerodynamic performance of the hind wing. The roles of the spiral Leading Edge Vortex （LEV） and the spanwise flow were clarified by comparing 2D and 3D simulations. Mainly due to pitching down of chord line during downstroke in highly inclined stroke plane, relatively high averaged thrust was produced in the free forward flight of the beetle. The effects of the local corrugation and the camber variation were also investigated for the beetle＇s hind wings. Our results show that the camber variation plays a significant role in improving both lift and thrust in the flapping. On the other hand, the local corrugation pattern has no significant effect on the aerodynamic force due to large angle of attack during flapping.

关键词： beetle flight forward flight three-dimensional simulation corrugation effect time-camber variation

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A study implementing real-time PCR to identify Strongyloides species of third-stage larvae in human stool samples from Southern Vietnam

Infectious Medicine

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Infectious Medicine 2023年第3期2卷 229-236页

作者： Le Duc Vinh Nguyen Kim Thach Huynh Hong Quang Do Nhu Binh Tran Thi Duc Hanh Nguyen Minh Toàn Nguyen trung tuyen Nguyen Thu Huong Department of Medical Parasitology Pham Ngoc Thach University of MedicineHo Chi Minh City 700000Vietnam Department of Fundamental Chemistry-Biochemistry Pham Ngoc Thach University of MedicineHo Chi Minh City 700000Vietnam Clinical Epidemiology Research Unit Institute of MalariologyParasitologyand Entomology Quy NhonBinh Dinh 55000Vietnam Department of Infectious Disease Military Hospital 103Hanoi 100000Vietnam Department of Epidemiology Hanoi University of Public HealthHanoi 100000Vietnam Department of Microbiology-Parasitology Hanoi University of Public HealthHanoi 100000Vietnam Department of Medicine University of Medicine and PharmacyVietnam National UniversityHanoi100000 Vietnam

Background:Strongyloidiasis,a neglected disease caused by intestinal nematodes of the genus,is endemic to tropical and subtropical areas such as *** methods only identify the genus,while DNA-molecular techniques are susceptible in Strongyloides *** study aims to determine the prevalence of dominant Strongyloides species among the population in Duc Hoa district,Long An,***:A cross-sectional study used 1190 stool specimens collected from July 2017 to November *** samples were transported within 2 h,stored at 2-8℃,and processed within 48 h for microscopy smear and culture at the Laboratory of Medical Parasitology,Pham Ngoc Thach University of Medicine(PNT).Then all positive samples with the above 2 methods were verified by real-time PCR ***-time PCR amplification was conducted at the Laboratory of Molecular Biology,***:Direct microscopy and modified Harada-Mori culture detected Strongyloides *** in 79/1190 sam-ples(6.6%).About 94.2%of the DNA samples were Strongyloides stercoralis,2.9%were co-infections with Strongy-loides ratti and ***,and 2.9%were patients with *** identity of 12/14 sequences was confirmed as *** with a high level of similarity(91.3%-100%)and over 98%for ***:DNA-molecular techniques and sequence analysis are highly suitable for identifying Strongyloides species isolated from stool *** is remarkable evidence of the presence of zoonosis *** disease in human,not just the known *** is likely to result in a certain proportion of people being infected by this animal-borne infectious pathogen.

关键词： Strongyloidiasis Strongyloides stercoralis Strongyloides ratti DNA-molecular techniques

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Ecoregional variations of aboveground biomass and stand structure in evergreen broadleaved forests

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Journal of Forestry Research 2020年第5期31卷 1713-1722页

作者： Tran Van Do Mamoru Yamamoto Osamu Kozan Vo Dai Hai Phung Dinh trung Nguyen Toan Thang Lai Thanh Hai Vu Thanh Nam Trieu Thai Hung Hoang Van Thang Tran Duc Manh Cao Chi Khiem Vu Tien Lam Nguyen Quang Hung Tran Hoang Quy Pham Quang tuyen Trinh Ngoc Bon Nguyen Thi Thu Phuong Ninh Viet Khuong Nguyen Van Tuan Dang Thi Hai Ha Tran Hai Long Dang Van Thuyet Dang Thinh Trieu Nguyen Van Thinh Tran Anh Hai Duong Quang trung Nguyen Van Bich Dinh Hai Dang Pham Tien Dung Nguyen Huy Hoang Le Thi Hanh Phan Minh Quang Nguyen Thi Thuy Huong Hoang Thanh Son Nguyen Thanh Son Nguyen Thi Van Anh Nguyen Thi Hoai Anh Pham Dinh Sam Hoang Thi Nhung Hoang Van Thanh Nguyen Huu Thinh Tran Hong Van Ho trung Luong bui Kieu Hung Research Institute for Sustainable Humanosphere Kyoto UniversityUjiKyotoJapan Silviculture Research Institute Vietnamese Academy of Forest SciencesNorth Tu LiemHanoiVietnam Center for Southeast Asian Studies Kyoto UniversityKyotoJapan Vietnamese Academy of Forest Sciences North Tu LiemHanoiVietnam Vietnam Administration of Forestry No.2 Ngoc HaBa DinhHanoiVietnam

Biotic and abiotic factors control aboveground biomass(AGB)and the structure of forest *** study analyses the variation of AGB and stand structure of evergreen broadleaved forests among six ecoregions of Vietnam.A data set of 1731-ha plots from 52 locations in undisturbed old-growth forests was *** results indicate that basal area and AGB are closely correlated with annual precipitation,but not with annual temperature,evaporation or hours of *** area and AGB are positively correlated with trees>30 cm *** areas surveyed(52.6%)in these old-growth forests had AGB of 100–200 Mg ha^-1;5.2%had AGB of 400–500 Mg ha^-1,and 0.6%had AGB of>800 Mg ha^-*** percent of the areas surveyed had stand densities of 300–600 ***^-1,and 64%had basal areas of 20–40 m^2 ha^-*** is an important factor influencing the AGB of old-growth,evergreen broadleaved forests in *** causing the loss of large-diameter trees(e.g.,>100 cm DBH)affects AGB but may not seriously affect stand density.

关键词： Aboveground biomass Carbon storage Climatic variables Ecoregion Edaphic variables Oldgrowth forest

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Upconversion luminescence of Gd2O3:Er3+and Gd2O3:Er3+/silica nanophosphors fabricated by EDTA combustion method

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Journal of Rare Earths 2019年第11期37卷 1126-1131页

作者： Le Quoc Minh Tran Kim Anh Nguyen Duy Hung Pham Thi Minh Chau Nguyen Thi Quy Hai Ho Van tuyen Vu Thi Thai Ha Vu Duc Tu Wieslaw Strek Institute of Theoretical and Applied Research Duy Tan UniversityDa Nang 55000Viet Nam Advanced Institute for Science and Technology Hanoi University of Science and Technology1 Dai Co VietHai Ba TrungHanoiViet Nam Institute of Materials Science Vietnam Academy of Science and Technology18 Hoang Quoc Viet RoadCau Giay DistrictHanoiViet Nam Institute of Low Temperature and Structure Research Polish Academy of Science 2 OkolnaWroclawPoland

Gd2O3:Er^3+nanophosphors were fabricated by the combustion method in presence of Na2 ethylene diamine tetra acetic acid(EDTA-Na2)as fuel at not high temperature(≤350℃)within a very short time of 5 *** added concentration of Er^3+ions in Gd2O3 matrix was changed from 0.5 mol%to 5.0 mol%.The X-ray diffraction pattern of samples indicates the monoclinic structure of Gd2O3:Er^3+.The morphology and chemical composition analysis of the Gd2O3:Er^3+samples are characterized by a field emission scanning electron microscope(FESEM)and a Fourier-transform infrared spectrometer(FTIR).The photoluminescence(PL),photo luminescence excitation(PLE)and upconversion(UC)at room temperature of the prepared materials with different concentrations of Er^3+were *** PL of Gd2O3:Er^3+nanomaterials are shown in visible at 545,594,623,648,688 nm under excitation at 275 *** emission bands from transitions of Er^3+from 2P3/2 to 4F9/2 are observed,UC luminescent spectra of the Gd2O3:Er^3+/silica nanocomposites under 976 nm excitation show the bands at 548 and 670 *** influence of excitation power at 980 nm for transitions were measured and *** results indicate that the upconversion process of Gd2O3:Er^3+/silica is two photons absorption *** low temperature dependence of UC luminescent intensities of the main bands of Gd2O3:Er^3+was investigated towards development of a nanotemperature sensor in the range of 10-300 K.

关键词： Upconversion luminescence Gd2O3:Er3+ Gd2O3:Er3+/silica Nanophosphors EDTA combustion Rare earths

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Influence of Process Factors on Electrode Wear Rate when EDM 90CrSi Steel using Graphite Electrodes

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Journal of Environmental Science and Engineering(B) 2023年第5期12卷 230-235页

作者： Tran Huu Danh Le Thi Phuong Thao Nguyen Thi Quoc Dung Vu trung tuyen Luu Anh Tung Vinh Long University of Technology Education Vinh Long City 85110Vietnam Thai Nguyen University of Technology Thai Nguyen city 251750Vietnam National Research Institute of Mechanical Engineering Hanoi City 511309Vietnam

The findings of a study on the optimization of Electric Discharge Machining(EDM)procedure for processing cylindrically shaped components with graphite electrodes are presented in this *** steel 90CrSi was the material of choice for the study’s ***,the Electrode Wear Rate(EWR)was chosen as the optimization problem’s objective *** experiment using the Taguchi design was conducted to address this ***,experiments were created and their outcomes were analyzed using the Minitab R19 *** impact of the input process factors on EWR was investigated,including the powder concentration,the pulse on and off times,the servo current,and the servo ***,the best process variables for a minimal EWR were provided.

关键词： EDM process factor EWR 90CrSi.

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