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^(12)CO emission from the Red Rectangle

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Research in Astronomy and Astrophysics 2015年第12期15卷 2213-2228页

作者： Pham Tuan Anh Pham Ngoc diep do thi Hoai Pham Tuyet Nhung Nguyen thi Phuong Nguyen thi Thao Pierre Darriulat Department of Astrophysics Vietnam National Satellite CenterVAST

Observations of an unprecedented quality made by ALMA on the Red Rectangle of CO（3-2） and CO（6-5） emissions are analysed jointly with the aim of obtaining as simple as possible a description of the gas morphology and kinematics. Evidence is found for polar conical outflows and for a broad equatorial torus in rotation and expansion. Simple models of both are proposed. Comparing CO（6-5） and CO（3-2） emissions provides evidence for a strong temperature enhancement over the polar outflows. Continuum emission （dust） is seen to be enhanced in the equatorial region. Observed asymmetries are briefly discussed.

关键词： stars: AGB and post-AGB -- circumstellar matter -- radio-lines: stars-- planetary nebulae: individual (Red Rectangle)

Morphology and kinematics of the gas envelope of the Mira binary W Aquilae

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Research in Astronomy and Astrophysics 2016年第7期16卷 47-54页

作者： do thi Hoai Pham Tuyet Nhung Pham Ngoc diep Nguyen thi Phuong Pham Tuan-Anh Nguyen thi Thao Pierre Darriulat Department of Astrophysics Vietnam National Satellite CenterVAST

We analyse ALMA observations of the12CO（3-2） emission of the circumstellar envelope（CSE）of the Mira variable binary star W Aql. These provide, for the first time, spatially resolved doppler velocity spectra of the CSE up to angular distances to the central star ofy nature of the observations（only five minutes in each of～5′′（meaning some 2000 AU）. The explorator two different configurations） does not allow for a detailed modelling of the properties of the CSE but provides important qualitative information on its morphology and kinematics. Emission is found to be enhanced along an axis moving from east/west to north-east/south-west when the angular distance from the central star projected on the plane of the sky increases from zero to four arcseconds. In parallel, the doppler velocity distribution displays asymmetry along an axis moving from east/west to north-west/south-east. The results are discussed in the context of earlier observations, in particular of the dust morphology.

关键词： stars AGB and post-AGB (stars ) circumstellar matter stars individual(W Aql) stars mass-loss radio lines stars

Morphology and kinematics of the gas envelope of the variable AGB star π^1 Gruis

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Research in Astronomy and Astrophysics 2016年第7期16卷 97-104页

作者： Pham Tuyet Nhung do thi Hoai Pham Ngoc diep Nguyen thi Phuong Nguyen thi Thao Pham Tuan Anh Pierre Darriulat Department of Astrophysics Vietnam National Satellite CenterVAST

Observations of the ^12CO（3–2） emission from the circumstellar envelope（CSE） of the variable star π1Gru using the compact array of the ALMA observatory have been recently made accessible to the public. An analysis of the morphology and kinematics of the CSE is presented with a result very similar to that obtained earlier for ^12CO（2–1） emission using the Submillimeter Array. A quantitative comparison is made using their flared disk model. A new model is presented that provides a significantly better description of the data, using radial winds and smooth evolutions of the radio emission and wind velocity from the stellar equator to the poles.

关键词： stars AGB and post-AGB circumstellar matter star individual(π1Gru) stars massloss radio lines stars

Contributions of Rotation,Expansion and Line Broadening to the Morphology and Kinematics of the Inner CSE of Oxygen-rich AGB Star R Hya

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Research in Astronomy and Astrophysics 2023年第1期23卷 40-47页

作者： Pham Tuyet Nhung do thi Hoai Pierre Darriulat Pham Ngoc diep Nguyen Bich Ngoc Tran thi Thai Pham Tuan-Anh Department of Astrophysics Vietnam National Space CenterVietnam Academy of Science and Technology18Hoang Quoc VietNghia DoCau GiayHa NoiVietnam

We use archival ALMA observations of the CO(2-1)and SiO(5-4)molecular line emissions of AGB star R Hya to illustrate the relative contributions of rotation,expansion and line broadening to the morphology and kinematics of the circumstellar envelope(CSE)within some~70 au(~0."5)from the centre of the *** give evidence for rotation and important line broadening to dominate the inner region,within~14 au(~100 mas)from the centre of the *** former is about an axis that projects a few degrees west of north and has a projected rotation velocity of a few km s^(-1).The latter occurs within some 7-14 au(50-100 mas)from the centre of the star,with the line width reaching two to three times its value outside this *** suggest that it is caused by shocks induced by stellar pulsations and convective cell *** show the importance of properly accounting for the observed line broadening when discussing rotation and evaluating the radial dependence of the rotation velocity.

关键词： stars AGB and post-AGB-(stars:)circumstellar matter-radio lines

ALMA observations of the circumstellar envelope around EP Aqr

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Research in Astronomy and Astrophysics 2019年第3期19卷 97-110页

作者： Pham thi Tuyet Nhung do thi Hoai Pham Tuan-Anh thibaut Le Bertre Pierre Darriulat Pham Ngoc diep Nguyen thi Phuong Nguyen thi Thao Jan Martin Winters Department of Astrophysics Vietnam National Space CenterVAST LERMA UMR 8112 CNRS and Observatoire de Paris PSL Research University Graduate University of Science and Technology VAST IRAM 300 rue de la Piscine Domaine Universitaire

Atacama Large Millimetre/sub-millimetre Array(ALMA) observations of CO(1–0) and CO(2–1) emissions from the circumstellar envelope of the asymptotic giant branch(AGB) star EP Aqr have been made with four times better spatial resolution than previously available. They are analysed with emphasis on the de-projection in space of the effective emissivity and flux of matter using as input a prescribed configuration of the velocity field, assumed to be radial. The data are found to display an intrinsic axisymmetry with respect to an axis making a small angle with respect to the line of sight. A broad range of wind configurations, from prolate(bipolar) to oblate(equatorial) has been studied and found to be accompanied by significant equatorial emission. Qualitatively, the effective emissivity is enhanced near the equator to produce the central narrow component observed in the doppler velocity spectra and its dependence on star latitude generally follows that of the wind velocity with the exception of an omni-present depression near the poles. In particular, large equatorial expansion velocities produce a flared disc or a ring of effective emissivity and mass loss. The effect on the determination of the orientation of the star axis of radial velocity gradients, and possibly competing rotation and expansion in the equatorial disc, is discussed. In general,the flux of matter is found to reach a broad maximum at distances of the order of 500 AU from the *** are given that may be used to favour one wind velocity distribution over another. As a result of the improved quality of the data, a deeper understanding of the constraints imposed on morphology and kinematics has been obtained.

关键词： stars: AGB and post-AGB (stars:) circumstellar matter stars: individual: EP Aqr stars:mass-loss radio lines: stars

Morphology of the ^(13)CO(3–2) millimetre emission across the gas disc surrounding the triple protostar GG Tau A using ALMA observations

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Research in Astronomy and Astrophysics 2018年第3期18卷 63-76页

作者： Nguyen thi Phuong Pham Ngoc diep Anne Dutrey Edwige Chapillon Pierre Darriulat Stéphane Guilloteau do thi Hoai Pham Tuyet Nhung Ya-Wen Tang Nguyen thi Thao Pham Tuan-Anh Department of Astrophysics Vietnam National Space CenterVietnam Academy of Science and Technology Graduate University of Science and Technology Vietnam Academy of Science and Technology Laboratoire d’Astrophysique de Bordeaux Université de Bordeaux IRAM F-38406 Saint Martin d’Hères Cedex Academia Sinica Institute of Astronomy and Astrophysics

Observations by the Atacama Large Millimetre/sub-millimetre Array of the dust continuum and ^13 CO（3–2） millimetre emissions of the triple stellar system GG Tau A are analysed,giving evidence for a rotating gas disc and a concentric and coplanar dust ring. The present work complements an earlier analysis（Tang et al.） by exploring detailed properties of the gas disc. A 95% confidence level upper limit of 0.24＂（34 au） is placed on the disc scale height at a distance of 1＂（140 au） from the central stars. Evidence for Keplerian rotation of the gas disc is presented,with the rotation velocity reaching-3.1 km s^-1 at 1＂ from the central stars,and a 99% confidence level upper limit of 9% is placed on relative contribution from a possible in-fall velocity. Variations of the intensity across the disc area are studied in detail and confirm the presence of a hot spot in the south-eastern quadrant. However several other significant intensity variations,in particular a depression in the northern direction,are also revealed. Variations of the intensity are found to be positively correlated to variations of the line width. Possible contributions to the measured line width are reviewed,suggesting an increase of the disc temperature and opacity with decreasing distance from the stars.

关键词： protoplanetary disks - stars low-mass - stars individual (GG Tau A)

Gravitationally lensed extended sources: the case of QSO RXJ0911

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Research in Astronomy and Astrophysics 2013年第7期13卷 803-814页

作者： do thi Hoai Pham Tuyet Nhung Pham Tuan Anh Frederic Boone Pierre Darriulat Pham Ngoc diep Pham Ngoc dong Nguyen Van Hiep Nguyen thi Thao VATLY INST179Hoang Quoc VietCau GiayHanoiVietnam IRAP 14avenue Edouard BelinF31400 ToulouseFrance

After a brief reminder of the mechanism of gravitational lensing of ex- tended sources, the particular case of the host galaxy of QSO RXJ0911, a high red-shift （z - 2.8） quadruply imaged quasar, is explored. The non linearity of the problem, together with the proximity of the source to a cusp of the lens inner caustic, has impor-tant consequences on the dependence of the image appearance on the size and shape of the source. Their expected main features and their interpretation in terms of source extension and shape are investigated in a spirit of simplicity and in preparation for the analysis of high sensitivity and spatial resolution images that will soon be within reach with the completion of the Atacama Large Millimeter/submillimeter Array （ALMA）. In particular, the information on source size carded by relative image brightness is dis-cussed. Extension of the results to other types of quadruply imaged quasars is briefly considered.

关键词： gravitational lensing - galaxies: high-redshift

The future of COVID-19 vaccination rates for children

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Asian Pacific Journal of Tropical Medicine 2022年第9期15卷 381-382页

作者： Giao Huynh Kimberly H.Nguyen Han thi Ngoc Nguyen Tuan diep Tran Pham Le An Faculty of Public Health University of Medicine and Pharmacy at Ho Chi Minh CityHo Chi Minh CityVietnam Department of Public Health and Community Medicine Tufts University School of MedicineBostonMAUSA Infection Control Department University Medical Center Ho Chi Minh CityHo Chi Minh CityVietnam Faculty of Medicine University of Medicine and Pharmacy at Ho Chi Minh CityHo Chi Minh CityVietnam Family Medicine Training Center University of Medicine and Pharmacy at Ho Chi Minh CityHo Chi Minh CityVietnam

The COVID-19 pandemic has been ongoing for over two years since the first case was reported in the end of January *** has successfully controlled the pandemic through its vaccination campaign,targeted messages and applications of various public health interventions including social distancing,quarantining,masking,and hand washing,which have made some significant achievements in reducing hospitalizations and deaths[1].

关键词： vaccination targeted COV

Flood Hazard Mapping at Long Xuyen Quadrangle in2015 Using Geographic Information System and RemoteSensing Technologies

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Journal of Environmental Science and Engineering(B) 2019年第5期8卷 197-203页

作者： Nguyen thi Hong diep Tran Huu Duy Phan Kieu Diem Nguyen thi Be Nam Nguyen thi ThanhHuong Land Resources Department College of Environment and Natural ResourcesCan Tho UniversityCan Tho 940000Vietnam The Southwest Information and Appraisal Corporation(SIAC) Cantho 94000Vietnam Department of Natural Resources and Environment in Kien Giang Province Kien Giang 920000Vietnam Forest Ecology and Environment Department Faculty of Agriculture and ForestryTay Nguyen UniversityDakLak 630000Vietnam

In recent year,the flooding has occurred with high frequency at LXQ(Long Xuyen Quadrangle)areas of Mekong Delta,*** was considered as a major natural disaster which has effects on the physic and spirit in people’s life in this *** research aims to generate a flood hazard map and assess the flood situation at LXQ in *** MNDWI(Modification of Normalized Difference Water Index)extracting from Sentinel-2 image was used to map the flood extent at LXQ during rainy season in *** statistics method estimated correlation coefficient between flooding spatial distribution and hydrological stations on SPSS(Statistical Product and Services Solutions)*** results showed that the severe flood occurred from August to December in *** were about 47.6%and 28.2%of the total areas that were inundated in October and August,*** correlation between inundated areas and water level at Ha Tien and Chau doc hydrological stations was 0.73 and 0.65(p<0.01),*** derived information was very essential and valuable for local managers in making decision on responding and mitigating to the flood disaster.

关键词： Flood distribution MNDWI LXQ correlation coefficient