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ALMA observations of the circumstellar envelope around EP Aqr

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

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Off-the-shelf mesenchymal stem cells from human umbilical cord tissue can significantly improve symptoms in COVID-19 patients: An analysis of evidential relations

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World Journal of Stem Cells 2020年第8期12卷 721-730页

作者： Phuc Van pham Ngoc Bich Vu Stem Cell Institute University of ScienceHo Chi Minh 08000Viet Nam Vietnam National University Ho Chi Minh 08000Viet Nam

Coronavirus disease-2019(COVID-19)has affected more than 200 countries *** disease has hugely affected healthcare systems as well as the economy to an extent never seen *** date,COVID-19 infection has led to about 165000 deaths in 150 *** present,there is no specific drug or efficient treatment for this *** this analysis based on evidential relationships of the biological characteristics of MSCs,especially umbilical cord(UC)-derived MSCs as well as the first clinical trial using MSCs for COVID-19 treatment,we discuss the use of UC-MSCs to improve the symptoms of COVID-19 in patients.

关键词： Coronavirus COVID-19 Mesenchymal stem cells Umbilical cord-derived mesenchymal stem cells

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中日对越南投资比较研究（1991-2016）

中日对越南投资比较研究（1991-2016）

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作者：范德华（pham DUC hoang）云南大学

学位级别：硕士

越南自革新开放以来。积极主动融入国际经济,注重吸引外国的直接投资,外国的资本也为越南的发展注入了新的活力,加速越南工业化和现代化国家的进程。中国和日本一直都是越南主要的投资来源国,两国对越南的投资也有明显的成效,同时存在... 详细信息

越南自革新开放以来。积极主动融入国际经济,注重吸引外国的直接投资,外国的资本也为越南的发展注入了新的活力,加速越南工业化和现代化国家的进程。中国和日本一直都是越南主要的投资来源国,两国对越南的投资也有明显的成效,同时存在着时代的特点。本文试图通过两国在1991年以来对越南投资的比较,全面分析两国对越南投资的现状,呈现更多两国对越南投资的新特点,并且通过比较发掘两国在对越南投资中的优劣,寻求存在异同和优劣的原因,针对两国的投资特点进一步完善越南引入外资的政策,达到充分利用外资并且优化外资投资结构的目的。在研究内容方面,本文对中国和日本在越南的投资主要从投资规模及区域、投资偏好及影响、投资趋势及态度等全方位进行,在梳理1991年以来两国对越南投资的各方面数据和资料中比较异同。比较分析中日两国对越南投资得出的结论是:一是中国对越南的投资规模还有较大的发展空间;二是日本投资结构较中国更不够合理,对第二产业的投资占比较大,缺乏投资质量;三是中日两国对投资选择有着不同的偏向,主要受地方政策、地理条件和投资偏好的影响;四是在越南对中国和日本投资态度以及两国发展趋势的比较中可进一步规划投资战略。总之,越南应根据投资现状与发展趋势对中日的投资寻求更为健康、合理的投资策略,有效利用中日对越的外资投资,促进越南经济特别的对外经济的良性发展。

关键词：中国日本直接投资

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Classification of Short Time Series in Early Parkinson’s Disease With Deep Learning of Fuzzy Recurrence Plots

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IEEE/CAA Journal of Automatica Sinica 2019年第6期6卷 1306-1317页

作者： Tuan D.pham Karin Wardell Anders Eklund Goran Salerud Department of Biomedical Engineering the Center for Medical Image Science and VisualizationLinkoping UniversityLinkopingSweden the Center for Artificial Intelligence Prince Mohammad Bin Fahd UniversityAl KhobarKingdom of Saudi Arabia Department of Biomedical Engineering Linkoping UniversityLinkopingSweden Department of Biomedical Engineering the Department of Computer and Information Sciencethe Center for Medical Image Science and VisualizationLinkoping UniversityLinkopingSweden

There are many techniques using sensors and wearable devices for detecting and monitoring patients with Parkinson’s disease(PD).A recent development is the utilization of human interaction with computer keyboards for analyzing and identifying motor signs in the early stages of the *** designs for classification of time series of computer-key hold durations recorded from healthy control and PD subjects require the time series of length to be considerably *** an attempt to avoid discomfort to participants in performing long physical tasks for data recording,this paper introduces the use of fuzzy recurrence plots of very short time series as input data for the machine training and classification with long short-term memory(LSTM)neural *** an original approach that is able to both significantly increase the feature dimensions and provides the property of deterministic dynamical systems of very short time series for information processing carried out by an LSTM layer architecture,fuzzy recurrence plots provide promising results and outperform the direct input of the time series for the classification of healthy control and early PD subjects.

关键词： Deep learning early Parkinson’s disease(PD) fuzzy recurrence plots long short-term memory(LSTM) neural networks pattern classification short time series

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Free vibration analysis of functionally graded porous curved nanobeams on elastic foundation in hygro-thermo-magnetic environment

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Frontiers of Structural and Civil Engineering 2023年第4期17卷 584-605页

作者： Quoc-Hoa pham Parviz MALEKZADEH Van Ke TRAN Trung NGUYEN-THOI Faculty of Engineering and Technology Nguyen Tat Thanh UniversityHo Chi Minh City 700000Vietnam Department of Mechanical Engineering Persian Gulf UniversityBushehr ***Iran Faculty of Mechanical Engineering Le Quy Don Technical UniversityHanoi 100000Vietnam Laboratory for Applied and Industrial Mathematics Institute for Computational Science and Artificial IntelligenceVan Lang UniversityHo Chi Minh City 700000Vietnam Faculty of Mechanical-Electrical and Computer Engineering School of TechnologyVan Lang UniversityHo Chi Minh City 700000Vietnam Bualuang ASEAN Chair Professor Thammasat School of EngineeringThammasat UniversityPathumtani 12120Thailand

Herein,a two-node beam element enriched based on the Lagrange and Hermite interpolation function is proposed to solve the governing equation of a functionally graded porous(FGP)curved nanobeam on an elastic foundation in a hygro–thermo–magnetic *** material properties of curved nanobeams change continuously along the thickness via a power-law distribution,and the porosity distributions are described by an uneven porosity *** effects of magnetic fields,temperature,and moisture on the curved nanobeam are assumed to result in axial loads and not affect the mechanical properties of the *** equilibrium equations of the curved nanobeam are derived using Hamilton’s principle based on various beam theories,including the classical theory,first-order shear deformation theory,and higher-order shear deformation theory,and the nonlocal elasticity *** accuracy of the proposed method is verified by comparing the results obtained with those of previous reliable ***,the effects of different parameters on the free vibration behavior of the FGP curved nanobeams are investigated comprehensively.

关键词： functionally graded porous material curved nanobeam hygro-thermo-magnetic enriched finite element method

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Performance evaluation of high/ultra-high-degree global geopotential models over Vietnam using GNSS/leveling data

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Geodesy and Geodynamics 2023年第5期14卷 500-512页

作者： Hoa Thi pham Sten Claessens Michael Kuhn Joseph Awange School of Earth and Planetary Sciences Spatial Sciences DisciplineCurtin UniversityPerthAustralia Faculty of Surveying Mapping and Geographic InformationHanoi University of Natural Resources and EnvironmentHanoiViet Nam

The availability of many high-degree Global Geopotential Models(GGMs), namely EGM2008, EIGEN-6C4,GECO, SGG-UGM-1, SGG-UGM-2, XGM2019e_2159, and GGMPlus, challenges users regarding which model is best for Vietnam. This study, therefore, evaluates their performance by comparing them with GNSS/leveling data over Vietnam. Results show that their absolute and relative performances are largely independent of topographic conditions and geographical location and can be ranked into three classes:(1)XGM2019e_2159 has the highest accuracy,(2) the models EIGEN-6C4, GECO, SGG-UGM-1, SGG-UGM-2, and GGMPlus, have a very similar level of medium accuracy, while(3) EGM2008 is found to be the least accurate. In an absolute sense, the differences between GNSS/leveling and EGM2008-based height anomalies have a standard deviation(STD) of 0.290 ± 0.010 m, whereas, for XGM2019e_2159, this is 0.156 ± 0.006 *** other models have STDs of(0.18-0.19) ± 0.007 m. Regarding relative performance without fitting, all GGMs have comparable accuracies for baseline length of 5-20 km, while for baselines longer than 20 km,the STD of XGM2019e_2159 is 1.5 ppm-0.5 ppm(approximately 19%-40%) lower compared with EGM2008, and 0.5 ppm-0.25 ppm(approximately 7%-36%) lower compared with EIGEN6C4, GECO,SGG-UGM-1, SGG-UGM-2, and GGMPlus. In addition, the STDs decrease significantly from 20 to 12 ppm in the range of 5-10 km, slightly from 12 to 6 ppm for 10-35 km, very slightly from 6 to 2.5 ppm for35-200 km, and then remain almost unchanged for longer baselines. After fitting, the relative accuracies of all GGMs are at the same level with negligible STD/RMSE values. Furthermore, only EGM2008 experiences significant regional differences, while other GGMs show more homogeneous spatial variation of absolute accuracy over Vietnam. These findings can contribute to the development of local quasigeoid models in Vietnam and may be helpful with the improvement of GGMs in the future.

关键词： GGM Evaluation GNSS/Leveling EGM2008 EIGEN-6C4 GECO SGG-UGM-1 SGG-UGM-2 XGM2019e_2159 GGMPlus

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Performance evaluation of a two-way relay network with energy harvesting^and hardware noises

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Digital Communications and Networks 2021年第1期7卷 45-54页

作者： Nguyen Tien Tung pham Minh Nam Phu Tran Tin Faculty of Electronics Technology Industrial University of Ho Chi Minh CityHo Chi Minh CityVietnam Wireless Communcations Research Group Faculy of Electrical and Electronics EngineeringTon Duc Thang UniversityHo Chi Minh CityVietnam

In this paper,we propose a Two-Way Cognitive Relay Network(TWCRN)where the secondary users operate on an underlay mode to access the licensed *** the proposed protocols,two secondary sources transmit their data to a relay in the first time slot,and then the relay would forward the received information to both sources in the remaining ***,the relay is self-powered by harvesting energy from ambient Radio Frequency(RF)signals,using the Time Switching(TS)and the Power Switching(PS)*** paper concentrates on eval-uating the performance of the secondary networks under the impact of hardware impairments and co-channel interference from the primary *** particular,based on the secondary transmitters'constraint power,we derive the closed-form expressions of the outage probability and the throughput over Rayleigh fading channels in two cases:TS and *** also investigate the energy efficiency issue and the locally optimal position of the relay to maximize the system throughput,which provides much information to install the relay ***,our derivations are verified by Monte Carlo simulation.

关键词： Energy harvesting Two-way relay Energy efficiency Hardware impairments Cognitive network

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Effect of heating time on structural,morphology,optical,and photocatalytic properties of g-C3N4 nanosheets

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Chinese Physics B 2020年第5期29卷 504-508页

作者： Nguyen Manh Hung Le Thi Mai Oanh Lam Thi Hang pham Do Chung pham Thi Duyen Dao Viet Thang Nguyen Van Minh Center for Nano Science and Technology Hanoi National University of Education136 Xuan Thuy RoadCau Giay DistrictHanoi100000Vietnam Department of Physics Hanoi National University of Education136 Xuan Thuy RoadCau Giay DistrictHanoi100000Vietnam Faculty of Basic Sciences Hanoi University of Natural Resources and Environment41A Phu Dien RoadNorth Tu LiemHanoi100000Vietnam Hanoi University of Mining and Geology Duc Thang wardNorth Tu Liem DistrictHanoi100000Vietnam Military science Academy 322 Le Trong Tan streetDinh CongHoang MaiHanoi100000Vietnam

Effect of heating time on the structural,morphology,optical,and photocatalytic properties of graphitic carbon nitride(g-C3N4)nanosheets prepared at 550℃in Ar atmosphere is *** investigations are carried out by using x-ray diffraction(XRD),scanning electron microscopy(SEM),Fourier-transform infrared spectroscopy(FTIR),UV-vis absorption,and photoluminescence(PL).At a heating temperature of 550℃,g-C3N4 nanocrystals are formed after 0.5 h and become more orderly as the heating time *** surface area of the g-C3N4 nanosheets significantly increases as the preparation time *** g-C3N4 prepared in 2.5 h shows the highest photocatalytic performance,decomposing completely 10 ppm RhB solution under xenon lamp irradiation for 2.0 h.

关键词： nanosheets photocatalytic heating time Ar atmosphere

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Editorial

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Journal of Social Computing 2021年第3期2卷 I0001-I0002页

作者： Green, Ben pham, Kathy

We are thrilled to present this special issue of the Journal of Social Computing,entitled“Technology Ethics in Action:Critical and Interdisciplinary Perspectives”.This special issue interrogates the meaning and impacts of“tech ethics”:the embedding of ethics into digital technology research,development,use,and *** response to concerns about the social harms associated with digital technologies,many individuals and institutions have articulated the need for a greater emphasis on ethics in digital *** as more groups embrace the concept of ethics,critical discourses have emerged questioning whose ethics are being centered,whether“ethics”is the appropriate frame for improving technology,and what it means to develop“ethical”technology in practice.

关键词： technology. ethics discourse

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Integrated universal soil loss equation (USLE) and Geographical Information System (GIS) for soil erosion estimation in A Sap basin:Central Vietnam

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International Soil and Water Conservation Research 2018年第2期6卷 99-110页

作者： Tung Gia pham Jan Degener Martin Kappas Cartography GIS and Remote Sensing DepartmentGottingen UniversityGermany University of Agriculture and Forestry Hue UniversityVietnam

Central Vietnam is very susceptible to soil erosion due to its complicated terrain and heavy rainfall. The objective of this study was to quantify soil erosion in the A Sap river basin, A Luoi district, Thua Thien Hue Province, Vietnam, using the Universal Soil Loss Equation (USLE) and Geographical Informa-tion System (GIS). The results showed that 34% of land area lost accumulated to 10 t ha-1 year-1 while 47% of the total area lost less than 1 t ha-1 year-1. Natural forest land lost the most with an average of about 19 t ha-1 year-1, followed by plantation forest with approximately 7 t ha-1 year-1 and other agricultural lands at 3.70 and 1.45 t ha-1 year-1 for yearly crops and paddy rice, respectively. Soil erosion was most sensitive to the topographic factor (LS), followed by the practice support factor (P), soil erodibility factor (K), cropping management (C), and the rainfall erosivity factor (R). Implications are that changes to the cultivated calendar and implementing intercropping are effective ways to prevent soil erosion in cultivated lands. Furthermore, introducing broad leaves trees for mountainous areas in A Sap basin was the most effective practice in reducing soil erosion. The study also pointed out that the combination of available data sources used with the USLE and GIS technology is a viable option to cal-culate soil erosion in Central Vietnam, which would allow targeted attention toward a solution is to reduce future soil erosion.

关键词： Central Vietnam GIS Soil erosion USLE

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