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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

黄芪多糖对丝裂霉素C(MMC)致骨髓抑制小鼠骨髓及脾脏造血祖细胞的生成作用的影响

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中国药理学通报 2003年第7期19卷 812-814页

作者：夏星 dao nguyen 美国泛华医药公司北京100020

目的　研究黄芪多糖 (APS)对MMC致骨髓抑制小鼠的骨髓和脾造血祖细胞生长的影响。方法　d 0腹腔注射丝裂霉素C(MMC) 7mg·kg- 1 ,APS皮下注射 1 0 0mg·kg- 1·d- 1 ,给药方案分 3种 :① 0～ 4d ,共 5d ;② 0～ 1 1d ,共 1 2d ;③ 1 2d... 详细信息

目的　研究黄芪多糖 (APS)对MMC致骨髓抑制小鼠的骨髓和脾造血祖细胞生长的影响。方法　d 0腹腔注射丝裂霉素C(MMC) 7mg·kg- 1 ,APS皮下注射 1 0 0mg·kg- 1·d- 1 ,给药方案分 3种 :① 0～ 4d ,共 5d ;② 0～ 1 1d ,共 1 2d ;③ 1 2d给药 ,3wk内给完 ,用造血细胞集落培养法观察APS的药理作用。结果　在d 3时 ,APS治疗组对MMC致骨髓抑制小鼠骨髓CFU C数目增加了 3倍 ,分别为 1 870±40 /股骨和 62 4 0± 1 1 0 /股骨 ,从d 3～d 1 8,APS治疗组的骨髓CFU C均高于模型组。在给MMC后d 1 4之前APS对脾CFU C的生长没有影响 ,APS在d 1 4和d 1 8时APS有刺激脾造血祖细胞增殖作用 (分别高 3倍和 2倍 )。

关键词：黄芪多糖 MMC 造血组细胞

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

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

Synthesis and characterization of core/shell structured nanophosphors CePO_4:Tb@LaPO_4 by solvothermal method

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Journal of Rare Earths 2011年第12期29卷 1147-1151页

作者： Dinh Xuan Loc Tran Thi Kim Chi Tran Thu Huong nguyen Vu Tran Kim anh Wieslaw Strek Le Quoc Minh Institute of Materials Science Vietnam Academy of Science and Technology Institute of Low Temperature and Structure Research Polish Academy of Sciences(PAN) University of Engineering and Technology

Core/shell structured CePO4：Tb（Ⅲ）@LaPO4 and CePOa：Tb（Ⅲ） were successfully synthesized in tris（2-ethylhexyl） phosphate （TEHP） and diethylene glycol （DEG） solvents for comparison of the two techniques in open air and closed reaction vessel. Morphology and crystal structure of the core/shell nanophosphors were determined by using X-ray diffraction （XRD） and transmission electron microscopy （TEM）, which showed that nanophosphors had diameter of about 5-10 nm with the monoclinic monazite phase. The nanophosphors obtained by close vessel procedure showed smaller size, more homogeneity and pure crystallite. The luminescent measurements were done upon the different excitation wavelengths in ultraviolet region and at room temperatm＇e to elucidate the influences of the used solvents and the reaction temperatures. It was found that CePO4：Tb@LaPO4 preparedby the close vessel synthesis showed the intensity of green band of the transfer from 5D4 to 7F5 energy level, which was strongly increased, and the luminescent decay time was 3.2 ms, which was longer than that of naked CePO4：Tb phosphor.

关键词： solvothermal synthesis luminescence CePOn:Tb CePOa:Tb@LaPO4 rare earths

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

Factors Affecting the Profitability of Cement ManufacturingEnterprises in Tuyen Quang Province

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Macro Management & Public Policies 2022年第2期4卷 20-28页

作者： Hoang anh dao Pham Thanh Tra Tran Thao nguyen Tantrao University Yenson DistrictTuyenquang ProvinceVietnam

This study focuses on analyzing the factors affecting the production and business efficiency of cement manufacturing enterprises in Tuyen Quang province. Production and business efficiency is measured by profitability ratios including return on assets (ROA), return on equity (ROE) and return on sales (ROS). Using a quantitative research method through estimating a linear regression model based on data of two cement manufacturing companies in the period 2019-2021, the research results show that the factors affecting business efficiency of cement manufacturing enterprises in Tuyen Quang province include size of enterprise, cost ratio, average collection period, inventory turnover, fixed assets turnover and debt ratio.

关键词： Business efficiency Profitability Cement manufacturing enterprises Tuyen Quang

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粉煤灰作惰性粒子的镍复合镀层(英文)

Transactions of Nonferrous Metals Society of China 2013年第8期23卷 2348-2353页

作者： Viet Hue nguyen Thi anh Tuyet NGO Hong Hanh PHAM Ngoc Phong nguyen Institute of Materials Science

用粉煤灰(FA)作为惰性粒子,电沉积得到复合镀层Ni/FA。粉煤灰的尺寸为3-7μm,主要成分是72%SiO2和25%Al2O3。进行电沉积的工艺条件是瓦兹镀镍液含粉煤灰的浓度为5、20、50 g/L,电流密度为2、4A/dm2,温度为50℃,磁搅拌速度为250 r/min。... 详细信息

用粉煤灰(FA)作为惰性粒子,电沉积得到复合镀层Ni/FA。粉煤灰的尺寸为3-7μm,主要成分是72%SiO2和25%Al2O3。进行电沉积的工艺条件是瓦兹镀镍液含粉煤灰的浓度为5、20、50 g/L,电流密度为2、4A/dm2,温度为50℃,磁搅拌速度为250 r/min。采用扫描电子显微镜(SEM+EDX)、电化学测试和硬度测量来研究复合镀层Ni/FA的形态、成分和性能。镀层中粉煤灰的含量与镀液中粉煤灰的浓度以及相关工艺参数有关。由于镀层中加入了粉煤灰从而使镀层的力学与电化学性能得到改善。复合镀层Ni/FA的硬度达HV430,而纯Ni镀层的硬度只有HV198。电化学测试表明,复合镀层Ni/FA的耐腐蚀比纯镍镀层的高。

关键词：复合镀层粉煤灰显微观硬度耐腐蚀性惰性粒子

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