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International Journal of Digital Earth 2019年第10期12卷 1118-1132页

作者： Quang-Thanh Bui Manh pham van Nguyen Thi Thuy Hang Quoc-Huy Nguyen Nguyen Xuan Linh pham Minh Hai Tran Anh Tuan pham van cu Center for Applied Research in Remote sensing and GIS(CARGIS) VNU University of ScienceHa NoiViet Nam VNU University of Science Ha NoiViet Nam Vietnam Institute of Geodesy and Cartography Ha NoiViet Nam Ministry of Education and Training Ha NoiViet Nam

This study proposed a novel object-based hybrid classification model named GMNN that combines Grasshopper Optimization Algorithm(GOA)and the multiple-class Neural network(MNN)for urban pattern detection in Hanoi,*** bands of SPOT 7 image and derivable NDVI,NDWI were used to generate image segments with associated attributes by PCI Geomatics *** segments were classified into four urban surface types(namely water,impervious surface,vegetation and bare soil)by the proposed ***,three training and validation datasets of different sizes were used to verify the robustness of this *** all tests,the overall accuracies of the classification were approximately 87%,and the Area under Receiver Operating Characteristic curves for each land cover type was ***,the performance of this model was examined by comparing several statistical indicators with common benchmark *** results showed that GMNN out-performed established methods in all comparable *** results suggested that our hybrid model was successfully deployed in the study area and could be used as an alternative classification method for urban land cover *** a broader sense,classification methods will be enriched with the active and fast-growing contribution of metaheuristic algorithms.

关键词： Urban remote sensing object-based classification neural network grasshopper optimization algorithm

Combining SnO_(2-x)and g-C_(3)N_(4)nanosheets toward S-scheme heterojunction for high selectivity into green products of NO degradation reaction under visible light

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Journal of Materiomics 2022年第1期8卷 1-8页

作者： pham van Viet Thanh-Dat Nguyen Dai-Phat Bui Cao Minh Thi Faculty of Materials Science and Technology University of ScienceVNU-HCM227 Nguyen Van Cu StreetDistrict 5Ho Chi Minh City700000Viet Nam Vietnam National University-Ho Chi Minh City Thu Duc DistrictHo Chi Minh City700000Viet Nam Ho Chi Minh City University of Technology(HUTECH) 475A Dien Bien Phu StreetBinh Thanh DistrictHo Chi Minh City700000Viet Nam

NOx emissions cause many negative impacts on the living *** photocatalysis of semiconductors is superior for nitric oxide(NO)degradation due to their low redox *** this report,we combine SnO_(2-x)/g-C_(3)N_(4)heterojunction photocatalyst toward the high selectivity into green products under visible light *** show that SnO_(2-x)/g-C_(3)N_(4)heterojunction degraded 40.8%of NO,which is 1.6 times higher than that of g-C_(3)N_(4).In addition,the selectivity coefficient of SnO_(2-x)/g-C_(3)N_(4)is higher 3 times than both pure SnO_(2-x)and g-C_(3)N_(4).Furthermore,SnO_(2-x)/g-C_(3)N_(4)expresses a superior stability for NO photocatalytic-degradation after five *** scavenger trapping test results,and electron spin resonance(ESR)analysis also provide more understanding of the charge transfer mechanism of ***_(2-x)/g-C_(3)N_(4)heterojunction shows a high removal efficiency of NO gas,making it an up-and-coming environmental treatment candidate.

关键词： G-C_(3)N_(4) NO removal Oxygen vacancies Photocatalysis S-scheme

A Simple Approach to the Fabrication of Graphene-Carbon Nanotube Hybrid Films on Copper Substrate by Chemical Vapor Deposition

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Journal of Materials Science & Technology 2015年第5期31卷 479-483页

作者： Nguyen van Chuc Cao Thi Thanh Nguyen van Tu Vuong T.Q Phuong pham Viet Thang Ngo Thi Thanh Tam Institute of Materials Science Vietnam Academy of Science and Technology Hanoi University of Science Vietnam National University

In this study,graphene-carbon nanotube（CNT） hybrid films were directly synthesized on polycrystalline copper（cu） substrates by thermal chemical vapor deposition（CVD） *** films were synthesized on cu substrate at 1000 ℃ in mixture of gases:argon（Ar）,hydrogen（H2）,and methane（CH4）.Then,carbon nanotubes（CNTs） were grown uniformly on the surface of graphene/cu films at 750 ℃ in mixture of Ar,*** acetylene（C2H2） *** salt FeCl3solution deposited onto the surface of graphene/cu substrate by spin coating method was used as precursor for the growth of the *** density and quality of the CNTs on the surface of graphene/cu films can be controlled by varying the concentration of FeCl3salt catalyst.

关键词： Graphene Carbon nanotube(CNT) Hybrid films Copper

BTEX pollution caused by motorcycles in the megacity of HoChiMinh

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Journal of Environmental Sciences 2013年第2期25卷 348-356页

作者： Tran Thi Ngoc Lan pham Anh Minh University of Science Vietnam National University227 Nguyen Van CuHoChiMinh 70000Vietnam

Monitoring of benzene, toluene and xylenes （BTEX） was conducted along with traffic counts at 17 roadside sites in urban areas of HoChiMinh. Toluene was the most abundant substance, followed by p,m-xylenes, benzene, o-xylene and ethylbenzene. The maximum observed hour-average benzene concentration was 254 μg/m3 . Motorcycles contributed to 91% of the traffic fleet. High correlations among BTEX species, between BTEX concentrations and the volume of on-road motorcycles, and between inter-species ratios in air and in gasoline indicate the motorcycle-exhaust origin of BTEX species. Daily concentrations of benzene, toluene, ethylbenzene, p,m-xylenes and o-xylene were 56, 121, 21, 64 and 23 μg/m 3 , respectively. p,m-xylenes possess the highest ozone formation potential among the BTEX family.

关键词： air pollution benzene BTEX HoChiMinh motorcycle exhaust

Evaluation of five gridded rainfall datasets in simulating streamflow in the upper Dong Nai river basin,Vietnam

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International Journal of Digital Earth 2019年第3期12卷 311-327页

作者： pham Thi Thao Nhi Dao Nguyen Khoi Nguyen Xuan Hoan Institute of Research and Development Duy Tan UniversityDa NangVietnam Institute for Computational Science and Technology Tan Hiep Chanh WardDistrict 12Ho Chi Minh CityVietnam Faculty of Environment University of ScienceVietnam National University Ho Chi Minh City227 Nguyen Van Cu StreetDistrict 5Ho Chi Minh CityVietnam Ho Chi Minh City University of Food Industry 140 Le Trong Tan StreetTan Phu DistrictHo Chi Minh CityVietnam

Rainfall data with an appropriate spatial resolution is a key input to hydrological ***,networks of rain gauges are often sparsely and unevenly distributed in large catchments,especially in developing ***-resolution rainfall datasets,such as the Asian Precipitation Highly Resolved Observational Data Integration Towards Evaluation of Water Resources(APHRODITE),the Climate Forecast System Reanalysis(CFSR),the Climatic Research Unit Time Series(CRUTS),the Global Precipitation Climatology Centre(GPCC)and the Tropical Rainfall Measuring Mission(TRMM),have become available to overcome such *** objective of this study was to evaluate the impacts of four land-based rainfall products(APHRODITE,CFSR,CRU-TS,and GPCC)and a satellite-based rainfall product(TRMM)on streamflow of the upper catchment of Tri An reservoir in Vietnam using the Hydrological Modeling System(HEC-HMS).In addition,the available rain gauges data were used for comparison *** indicates that the TRMM and GPCC data show their best match to rain gauges data in simulating the streamflow in the period 1999–***,the results indicate that the TRMM and GPCC data could be alternative solutions.

关键词： APHRODITE CFSR CRU-TS GPCC TRMM rainfall streamflow HEC-HMS model

Tunable colors and conductivity by electroless growth of cu/cu2O particles on sol-gel modified cellulose

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Nano Research 2020年第10期13卷 2658-2664页

作者： Justus Landsiedel Waleri Root Christian Schramm Alexander Menzel Steffen Witzleben Thomas Bechtold Tung pham Research Institute for Textile Chemistry and Textile Physics University of Innsbruck6850 DornbirnAustria Department of Physical Chemistry University of Innsbruck6020 InmsbruckAustria Department of Natural Sciences Bonn Rhein sSieg University of Applied Sciences5359 RheinbachGermany

Development of colored surfaces by formation of nano-structured aggregates is a widely used strategy in nature to color lightweight structures (e.g. butterflies) without the use of dye pigments. The deposition of nanoscale particles mimics nature in it’s approach coloring surfaces. This work presents sol-gel modification of cellulose surfaces used to form a template for growth of cu/cu2O core–shell particles with defined size-distributions. Besides improving the adhesion of the deposited particulate material, the sol-gel matrix serves as a template for the control of particle sizes of the cu/cu2O structures, and as a consequence of particle size variation the surface color is tunable. As an example, red color was achieved with an average particle size of 35 nm, and shifts gradually to blue appearance when particles have grown to 80 nm on the sol-gel modified fabric. The copper concentration on representative fabrics is kept low to avoid modifying the textile characteristics and were all in the range of 150–170 mg per g of cellulose material. As a result of copper deposition on the surface of the material, the cellulose fabric also became electrically conductive. Remarkably, the electrical conductivity was found to be dependent on the average particle sizes of the deposits and thus related to the change in observed color. The generation of color by growth of nano-sized particles on sol-gel templates provides a highly promising approach to stain surfaces by physical effects without use of synthetic colorants, which opens a new strategy to improve environmental profile of coloration.

关键词： electroless copper deposition sol-gel support thin film structural coloration tunable sheet resistance LSPR

Examination of n-T_(9) conditions required by N=50,82,126 waiting points in r-process

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Communications in Theoretical Physics 2021年第10期73卷 147-157页

作者： Nguyen Duy Ly Nguyen Ngoc Duy Nguyen Kim Uyen Vinh N T pham Faculty of Fundamental Sciences Vanlang UniversityHo Chi Minh City 700000Vietnam Department of Physics Sungkyunkwan UniversitySuwon 16419Republic of Korea Department of Physics Ho Chi Minh City University of EducationHo Chi Minh City 700000Vietnam

We examined the conditions of neutron density(n) and temperature(T9) required for the N = 50, 82,and 126 isotopes to be waiting points(WP) in the r-process. The nuclear mass based on experimental data presented in the AME2020 database(AME and AME ± Δ) and that predicted using FRDM,WS4, DZ10, and KTUY models were employed in our estimations. We found that the conditions required by the N = 50 WP significantly overlap with those required by the N = 82 ones, except for the WS4 model. In addition, the upper(or lower) bounds of the n-T9 conditions based on the models are different from each other due to the deviations in the two-neutron separation *** standard deviations in the nuclear mass of 108 isotopes in the three N = 50, 82, and 126 groups are about rms = 0.192 and 0.434 Me V for the pairs of KTUY-AME and WS4-KTUY models,respectively. We found that these mass uncertainties result in a large discrepancy in the nn-T_(9) conditions, leading to significant differences in the conditions for simultaneously appearing all the three peaks in the r-process abundance. The newly updated FRDM and WS4 calculations can give the overall conditions for the appearance of all the peaks but vice versa for their old versions in a previous study. The change in the final r-process isotopic abundance due to the mass uncertainty is from a few factors to three orders of magnitude. Therefore, accurate nuclear masses of the r-process key nuclei, especially for 76 Fe,81cu,127Rh,132Cd,192Dy, and 197Tm, are highly recommended to be measured in radioactive-ion beam facilities for a better understanding of the r-process evolution.

关键词： neutron capture r-process nuclear mass isotopic abundance precise mass measurement

Hydrogenation of cinnamaldehyde over bimetallic Au-cu/CeO_2 catalyst under a mild condition

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Chinese Chemical Letters 2017年第2期28卷 293-296页

作者： Xue-Mei Liao Veronique Pitchon pham-Huu cuong Wei Chu Valerie Caps College of Food and Biological Engineering Xihua University ICPEES L'Institut de Chimie et Procedes pour l'energie l'environnement et la santé Université de Strasbourg Department of Chemical Engineering Sichuan University

Bimetallic Au_xcu_y/CeO_2（x/y = 3/1,1/1,and 1 /3） catalysts were prepared by direct anion exchange（DAE）,following impregnation（IMP） methods,and used for selective hydrogenation of *** effects of pretreatments,such as calcination or reduction on the catalytic activities of these catalysts were *** and HRTEM showed that for the reduced catalysts,there is the formation of an Au-cu ***-STEM displayed that reduction pretreatment leads to a very homogenous distribution of Au and cu on the external catalyst *** parameters,such as CAL concentration,the stirring speed,nature of the solvent influence the catalytic *** lead to a major effect on CAL conversion and HCAL *** Au_xcu_y/CeO_2 pretreated under reduction display higher CAL conversion and HCAL selectivity than that of under calcination mainly due to the synergistic effect resulting in a formation of Au-cu alloy.

关键词： Hydrogenation of cinnamaldehyde Bimetallic Au-cu catalysts Reduction or calcination Distribution Alloy

越南西北部Phan Si Pan地区新生代埃达克质侵入岩时代、成因及构造意义——U-Pb锆石年龄、元素地球化学和Hf同位素证据

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岩石学报 2012年第9期28卷 3031-3041页

作者： HIEU pham Trung 王涛童英 Faculty of Geology University of Sciences VNU-HCM227-Nguyen Van Cu StrHo Chi MinhVietnam Department of Geology Hanoi University of Mining and GeologyHanoiVietnam 中国地质科学院地质研究所北京100037

越南西北部PhanSiPan地区新生代花岗岩,高SiO2(69.95%～70.52%)、A12O3(15.77%～17.11%)、K2O(4.97%～5.63%)、Na2O(4.29%～4.98%),K2O/Na2O=1.02～1.31、Sr(744×10-6～1316×10-6),贫Y(6.93×10-6～8.06×10-6),低MgO和CaO,富集LILE元素及LREE,亏损HREE具有典型的埃达克岩特征。采用LA-ICPMS方法对该岩体进行了U-Pb同位素定年和Hf同位素分析,结果表明该岩体为始新世(38Ma)岩浆活动的产物。锆石Hf同位素研究结果显示,εHf(t)变化范围为-5.5至+7.3,二阶段Hf模式年龄(tDM2)为652Ma至1466Ma、集中在1.1～1.3Ga,说明花岗岩岩体主要由中-(新)元古代地壳物质部分熔融形成。部分锆石具有正的εHf(t)值,可能指示花岗岩岩浆形成的过程中存在壳-幔混合相互作用。越南西北部Phan Si Pan地区新生代花岗岩和扬子地块-(哀牢山-金沙江-红河带)高钾富碱的岩石形成的时代和机制具有密切的关系,可能与印度-亚洲大陆的碰撞导致红河带区域性走滑断裂系统的形成有关。

关键词：埃达克质岩锆石U-Pb年龄 Hf同位素越南西北部

Efficient and interpretable graph network representation for angle-dependent properties applied to optical spectroscopy

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npj Computational Materials 2022年第1期8卷 1434-1442页

作者： Tim Hsu Tuan Anh pham Nathan Keilbart Stephen Weitzner James Chapman Penghao Xiao S.Roger Qiu Xiao Chen Brandon C.Wood Center for Applied Scientific Computing Lawrence Livermore National LaboratoryLivermoreCAUSA Materials Science Division Lawrence Livermore National LaboratoryLivermoreCAUSA Department of Physics and Atmospheric Science Dalhousie UniversityHalifaxNSCanada

Graph neural networks are attractive for learning properties of atomic structures thanks to their intuitive graph encoding of atoms and ***,conventional encoding does not include angular information,which is critical for describing atomic arrangements in disordered *** this work,we extend the recently proposed ALIGNN(Atomistic Line Graph Neural Network)encoding,which incorporates bond angles,to also include dihedral angles(ALIGNN-d).This simple extension leads to a memory-efficient graph representation that captures the complete geometry of atomic ***-d is applied to predict the infrared optical response of dynamically disordered cu(II)aqua complexes,leveraging the intrinsic interpretability to elucidate the relative contributions of individual structural *** and dihedral angles are found to be critical contributors to the fine structure of the absorption response,with distortions that represent transitions between more common geometries exhibiting the strongest absorption *** directions for further development of ALIGNN-d are discussed.

关键词： representation disordered absorption