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Determination of Helmert transformation parameters for continuous GNSS networks:a case study of the Géoazur GNSS network

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Geo-Spatial Information Science 2023年第1期26卷 125-138页

作者： Dinh Trong Tran Jean-Mathieu Nocquet ngoc Dung luong Dinh Huy Nguyen Department of Geodesy and Geomatics Engineering Hanoi University of Civil EngineeringHanoiVietnam UniversitéCôte d’Azur CNRSObservatoire de la Côte d’AzurIRDValbonneFrance

In this paper,we propose an approach to determine seven parameters of the Helmert transfor-mation by transforming the coordinates of a continuous GNSS network from the World Geodetic System 1984(WGS84)to the International Terrestrial Reference *** includes(1)convert-ing the coordinates of common points from the global coordinate system to the local coordinate system,(2)identifying and eliminating outliers by the Dikin estimator,and(3)estimating seven parameters of the Helmert transformation by least squares(LS)estimation with the“clean”data(*** removed).Herein,the local coordinate system provides a platform to separate points’horizontal and vertical ***,the Dikin estimator identifies and eliminates outliers in the horizontal or vertical component *** is significant because common points in a continuous GNSS network may contain *** proposed approach is tested with the Géoazur GNSS network with the results showing that the Dikin estimator detects outliers at 6 out of 18 common points,among which three points are found with outliers in the vertical compo-nent ***,instead of eliminating all coordinate components of these six common points,we only eliminate all coordinate components of three common points and only the vertical component of another three common ***,the classical LS estimation is applied to“clean”data to estimate seven parameters of the Helmert transformation with a significant accuracy *** Dikin estimator’s results are compared to those of other robust estimators of Huber and Theil-Sen,which shows that the Dikin estimator performs ***,the weighted total least-squares estimation is implemented to assess the accuracy of the LS estimation with the same *** inter-comparison of the seven estimated parameters and their standard deviations shows a small difference at a few per million levels(E-6).

关键词： Continuous GNSS tectonic geodesy Dikin estimation Helmert transformation

Nitrate removal and extracellular polymeric substances of autohydrogenotrophic bacteria under various pH and hydrogen flow rates

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Journal of Environmental Sciences 2018年第1期30卷 50-57页

作者： Tran-ngoc-Phu Nguyen Pei-chung Chen Chihpin Huang Institute of Enuironmental Engineering National Chiao Tung UniuersityHsinchu 300Chinese Taipei

In recent years there has been an increasing interest in the use of autohydrogenotrophic bacteria to treat nitrate from wastewater. However, our knowledge about the characteristics of extracellular polymeric substances（EPS） releasing by these activities is not yet very advanced. This study aimed to investigate the change in EPS compositions under various p H values and hydrogen flow rates, taking into consideration nitrogen removal. Results showed that p H 7.5 and a hydrogen flow rate of 90 m L/min were the optimal operating conditions, resulting in 100% nitrogen removal after 6 hr of operation. Soluble and bound polysaccharides decreased, while bound proteins increased with increasing p H. Polysaccharides increased with increasing hydrogen flow rate. No significant change of bound proteins was observed at various hydrogen flow rates.

关键词： Autohydrogenotrophic bacteria Nitrate removal Extracellular polymeric substances Polysaccharides Proteins

Effects of C/N ratio on nitrate removal and floc morphology of autohydrogenotrophic bacteria in a nitrate-containing wastewater treatment process

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Journal of Environmental Sciences 2018年第7期30卷 52-60页

作者： Tran ngoc Phu Nguyen Shu-Ju Chao Pei-chung Chen Chihpin Huang Institute of EnvironmentaZ Engineering National Chiao Tung University Hsinchu 300 Chinese Taipei

The effects of C/N ratio of a nitrate-containing wastewater on nitrate removal performed by autohydrogenotrophic bacteria as well as on the morphological parameters of floc such as floc morphology, floc number distribution, mean particle size（MPS）, aspect ratio and transparency were examined in this study. The results showed that the nitrate reduction rate increased with increasing C/N ratio from 0.5 to 10 and that the nitrogen removal of up to 95% was found at the C/N ratios of higher than 5（between 0.5–10）. Besides, high C/N ratio values reflected a corresponding high nitrite accumulation after 12-hr operation, and a fast decreasing rate of nitrite in the rest of operational time. The final p H values increased with the C/N ratio increasing from 0.5 to 2.5, but decreased with the C/N ratio increasing from2.5 to 10. There were no significant changes in floc morphology with the MPSs ranging from35 to 40 μm. Small and medium-sized flocs were dominant in the sludge suspension, and the number of flocs increased with the increasing C/N ratios. Furthermore, the highest apparent frequency of 10% was observed at aspect ratios of 0.5 and 0.6, while the transparency of flocs changed from 0.1 to 0.7.

关键词： Autohydrogenotrophic bacteria C/N ratio Floc morphology Nitrate reduction Nitrite accumulation Nitrogen removal

Building 3D CityGML models of mining industrial structures using integrated UAV and TLS point clouds

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International Journal of Coal Science & Technology 2023年第5期10卷 158-177页

作者： Canh Le Van Cuong Xuan Cao Anh ngoc Nguyen chung Van Pham Long Quoc Nguyen Department of Mine Surveying Hanoi University of Mining and GeologyHanoiVietnam Viettel Group Viettel Cyberspace CenterHanoiVietnam

Mining industrial areas with anthropogenic engineering structures are one of the most distinctive features of the real world.3D models of the real world have been increasingly popular with numerous applications,such as digital twins and smart factory *** this study,3D models of mining engineering structures were built based on the CityGML *** collecting spatial data,the two most popular geospatial technologies,namely UAV-SfM and TLS were *** accuracy of the UAV survey was at the centimeter level,and it satisfied the absolute positional accuracy requirement of creat-ing all levels of detail(LoD)according to the CityGML ***,the UAV-SfM point cloud dataset was used to build LoD 2 *** addition,the comparison between the UAV-SfM and TLS sub-clouds of facades and roofs indicates that the UAV-SfM and TLS point clouds of these objects are highly consistent,therefore,point clouds with a higher level of detail and accuracy provided by the integration of UAV-SfM and TLS were used to build LoD 3 *** resulting 3D CityGML models include 39 buildings at LoD 2,and two mine shafts with hoistrooms,headframes,and sheave wheels at LoD3.

关键词： 3D modelling CityGML-Mining industry UAV Terrestrial laser scanning Point cloud

A New Species of Microhyla(Amphibia:Anura:Microhylidae)from Langbian Plateau,Central Vietnam

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Asian Herpetological Research 2020年第3期11卷 161-182页

作者： Van chung HOANG Mai Anh luong Quang Truong NGUYEN Nikolai L.ORLOV Youhua CHEN Bin WANG Jianping JIANG Chinese Academy of Sciences(CAS)Key Laboratory of Mountain Ecological Restoration and Bioresource Utilization and Ecological Restoration and Biodiversity Conservation Key Laboratory of Sichuan Province Chengdu Institute of BiologyCASChengdu 610041China University of Chinese Academy of Sciences Beijing 100049China Vietnam National Museum of Nature Vietnam Academy of Science and Technology18 Hoang Quoc Viet RoadHanoiVietnam Institute of Ecology and Biological Resources Vietnam Academy of Science and Technology18 Hoang Quoc Viet RoadHanoiVietnam Graduate University of Science and Technology Vietnam Academy of Science and Technology18 Hoang Quoc Viet RoadCau GiayHanoiVietnam Zoological Institute Russian Academy of SciencesUniversitetskaya nab 1St.Petersburg 199034Russia

We describe a new species,Microh yla hongiaoensis ***.,from Lam Dong Province,southern Vietnam based on morphological data and molecular *** new species is sister to *** by molecular phylogenetics and also most closely resembles *** in morphological characteristics,albeit differs from its congeners by a combination of the following morphological features:(1)size medium(SVL 13.6-14.7 mm in males and 18.3-18.6 mm in females);(2)fingers Ⅱ-Ⅳ with small disks,dorsal surface of disks,without median longitudinal groove;(3)webbing formula Ⅰ11/2 Ⅱ1-2 Ⅲ1-21/2Ⅳ21/4-1 Ⅴ;(4)toe disks with dorsal median longitudinal groove;(5)dorsal back without two small black spots;(6)one small black spot adjacent behind the eyes;(7)few small black scapular spots in the flanks-belly and inguinal region;(8)palm with two small metatarsal tubercles;(9)tibiotarsal reaching beyond *** *** in evergreen montane tropical forests at an elevation of 1500 m a.s.l.

关键词： new species Microhyla Bi Doup-Nui Ba national

A Study on Effects of Blade Pitch on the Hydrodynamic Performances of a Propeller by Using CFD

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Journal of Shipping and Ocean Engineering 2018年第1期8卷 36-42页

作者： NGUYEN Chi Cong luong ngoc Loi NGO Van He Vietnam Marine University Haiphong 180000 Vietnam Hanoi University of Science and Technology Hanoi 10000 Vietnam

The main objective of this work is to use the CFD （Computational Fluid Dynamics） technique to study the effects of pitch ratio on the controllable pitch propeller＇s thrust characteristic. The propeller analyzed is at the following design condition： diameter of 3.65 m, speed of 200 rpm, blade number of 4, average pitch of 2.459 m, pitch ratio at 0.7 of 0.6737. The first stage involves the mesh generation and refinement on domain of the designed propeller. The second stage deals with the identification of initial and boundary conditions of the mesh-equipped module. In the final stage, various results are calculated and analyzed for pitch ratio affecting on the propeller＇s thrust characteristic. The achieved results are the basis design and improving efficiency of the controllable pitch propeller.

关键词： Controllable pitch propeller propeller blade pitch ship CFD thrust.

Is convenience really king? Comparative evaluation of catastrophic costs due to tuberculosis in the public and private healthcare sectors of Viet Nam: a longitudinal patient cost study

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贫困所致传染病(英文) 2024年第2期13卷 1-12页

作者： Nguyen Hoa Binh Quang Vo Luan Nguyen Forse Rachel Jeanette Wiemers Anja Maria Christine Huynh Huy Ba Dong Thuy Thi Thu Phan Yen Thi Hoang Creswell Jacob Dang Thi Minh Ha Nguyen Lan Huu Shedrawy Jad L?nnroth Knut Nguyen Tuan Dinh Van Dinh luong Annerstedt Kristi Sidney Codlin Andrew James National Lung Hospital Ha Noi Viet Nam Friends for International TB Relief Ha Noi Viet Nam Department of Global Public Health WHO Collaboration Centre On Tuberculosis and Social Medicine Karolinska Institute Stockholm Sweden Stop TB Partnership Geneva Switzerland Pham ngoc Thach Hospital Ho Chi Minh City Viet Nam

Background In Viet Nam, tuberculosis (TB) represents a devastating life-event with an exorbitant price tag, partly due to lost income from daily directly observed therapy in public sector care. Thus, persons with TB may seek care in the private sector for its flexibility, convenience, and privacy. Our study aimed to measure income changes, costs and catastrophic cost incurrence among TB-affected households in the public and private *** Between October 2020 and March 2022, we conducted 110 longitudinal patient cost interviews, among 50 patients privately treated for TB and 60 TB patients treated by the National TB Program (NTP) in Ha Noi, Hai Phong and Ho Chi Minh City, Viet Nam. Using a local adaptation of the WHO TB patient cost survey tool, participants were interviewed during the intensive phase, continuation phase and post-treatment. We compared income levels, direct and indirect treatment costs, catastrophic costs using Wilcoxon rank-sum and chi-squared tests and associated risk factors between the two cohorts using multivariate *** The pre-treatment median monthly household income was significantly higher in the private sector versus NTP cohort (USD 868 vs USD 578;P=0.010). However, private sector treatment was also significantly costlier (USD 2075 vs USD 1313;P=0.005), driven by direct medical costs which were 4.6 times higher than costs reported by NTP participants (USD 754 vs USD 164;P<0.001). This resulted in no significant difference in catastrophic costs between the two cohorts (Private: 55% vs NTP: 52%;P=0.675). Factors associated with catastrophic cost included being a single-person household [adjusted odds ratio [(aOR=13.71; 95% confidence interval (CI): 1.36–138.14;P=0.026], unemployment during treatment (aOR=10.86; 95%CI: 2.64–44.60;P<0.001) and experiencing TB-related stigma (aOR=37.90; 95%CI: 1.72–831.73;P=0.021).Conclusions Persons with TB in Viet Nam face similarly high risk of catastrophic costs whether treated in the

关键词： Tuberculosis Patient cost Catastrophic cost Private sector Comparative analysis Viet Nam

Genome-wide SNP discovery and core marker sets for assessment of genetic variations in cultivated pumpkin(Cucurbita spp.)

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Horticulture Research 2020年第1期7卷 1139-1148页

作者： Nam ngoc Nguyen Minkyung Kim Jin-Kee Jung Eun-Jo Shim Sang-Min chung Younghoon Park Gung Pyo Lee Sung-Chur Sim Department of Bioresources Engineering Sejong UniversitySeoul 05006South Korea Seed Testing and Research Center Korea Seed&Variety ServiceGimcheon 39660South Korea Department of Life Sciences Dongguk UniversitySeoul 04620South Korea Department of Horticultural Bioscience Pusan National UniversityMiryang 50463South Korea Department of Plant Science and Technology Chung-Ang UniversityAnsung 17546South Korea Plant Engineering Research Institute Sejong UniversitySeoul 05006South Korea

Three pumpkin species Cucurbita maxima,***,and *** are commonly cultivated *** identify genome-wide SNPs in these cultivated pumpkin species,we collected 48 F1 cultivars consisting of 40 intraspecific hybrids(15 ***,18 ***,and 7 ***)and 8 interspecific hybrids(*** x ***).Genotyping by sequencing identified a total of 37,869 confident SNPs in this *** SNPs were filtered to generate a subset of 400 SNPs based on polymorphism and genome *** the 400 SNPs,288 were used to genotype an additional 188 accessions(94 F1 cultivars,50 breeding lines,and 44 landraces)with a SNP array-based *** polymorphisms were observed in 224 SNPs(78.0%)and were used to assess genetic variations between and within the four predefined populations in 223 cultivated pumpkin *** principal component analysis and UPGMA clustering found four major clusters representing three pumpkin species and interspecific *** genetic differentiation was supported by pairwise Fst and Nei’s genetic *** interspecific hybrids showed a higher level of genetic diversity relative to the other three *** the 224 SNPs,five subsets of 192,96,48,24,and 12 markers were evaluated for variety *** 192,96,and 48 marker sets identified 204(91.5%),190(85.2%),and 141(63.2%)of the 223 accessions,respectively,while other subsets showed<25%of variety identification *** SNP markers provide a molecular tool with many applications for genetics and breeding in cultivated pumpkin.

关键词： breeding cultivar Cucurbita

Development of high quality Fe_3O_4/rGO composited electrode for low energy water treatment

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Journal of Energy Chemistry 2016年第3期25卷 354-360页

作者： ngoc Tuan Trinh Sangho chung Jae Kwang Lee Jaeyoung Lee Electrochemical Reaction and Technology Laboratory School of Environmental Science and Technology Gwangju Institute of Science and Technology (GIST) Center for Chemical Energy Storage System Research Institute for Solar and Sustainable Energies GIST Ertl Center for Electrochemistry and Catalysis GIST

Electrochemical water treatment is an attractive technology for water desalination and softening due to its low energy consumption. Especially, capacitive Deionization(CDI) is promising as a future technology for water treatment. Graphene(rGO) has been intensively studied for CDI electrode because of its advantages such as excellent electrical conductivity and high specific surface area. However, its 2D dimensional structure with small specific capacitance, high resistance between layers and hydrophobicity degrades ion adsorption efficiency. In this work, we successfully prepared uniformly dispersed Fe3O4/rGO nanocomposite by simple thermal reactions and applied it as effective electrodes for CDI. Iron oxides play a role in uniting graphene sheets, and specific capacitance and wettability of electrodes are improved significantly;hence CDI performances are enhanced. The hardness removal of Fe3O4/rGO nanocomposite electrodes can reach 4.3 mg/g at applied voltage of 1.5V, which is 3 times higher than that of separate r GO *** this material is a promising candidate for water softening technology.

关键词： Electrochemical water treatment Capacitive deionization Water softening Grapheme Fe_3O_4/rGO nanocomposite Fe_3O_4 nanoparticle