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Piaoac Granites Related W-Sn Mineralization, Northern Vietnam: Evidences from Geochemistry, Zircon Geochronology and Hf Isotopes

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Journal of Earth Science 2019年第1期30卷 52-69页

作者： Tuan anh nguyen Xiaoyong Yang Hien Vu Thi Lei Liu Insung Lee School of Earth and Space Sciences University of Science and Technology of China Institute of Geological Sciences Vietnam Academy of Science and Technology(VAST) Department of Geology Hanoi University of Mining and Geology School of Earth and Environmental Sciences Seoul National University

Piaoac granites exposed in the Cao Bang region, northern Vietnam, are S-type granite, which are associated with W-Sn-Mo-Be-F mineralization. Zircon U-Pb ages, major and trace elements, mineral chemical and Hf isotopic compositions of the W-Sn-bearing granites from the Piaoac District have been investigated in detail. LA-ICP-MS U-Pb dating of zircon grains from these granites yielded ages of 82.5±2.3 and 82±1.8 Ma, representing an episode of Late Cretaceous magmatic event. These granites are characterized by high peraluminous and have typical S-type geochemical signatures with high SiO_2(72.37 wt.%–73.07 wt.%), high A/CNK values(1.61–1.65) and Al_2O_3(14.4 wt.%–15 wt.%). They are enriched in Rb, U, K, Th, Ta and Pb and display pronounced negative Ba, Sr, Nb, Ti and Eu(Eu/Eu*=0.19–0.24) anomalies. The high degree of fractional crystallization is characterized by low Rb, Sr, Ba and Eu concentrations with high ratios of La/Sm and Eu/Eu*. Zircon grains show εHf(t) values from-9.69 to-0.9 and the corresponding TDM2 range from 1.2 to 1.7 Ga, indicating that these granites could be derived from the Proterozoic basement rocks with minor input from mantle-derived magmas. The calculation of Fe^(3+) and Fe^(2+) of biotites indicates a low oxygen fugacity condition(log fO_2 ranging from 10-17 to 10-18 bars, below MH), which is favorable for the W-Sn mineralization. Tungsten and tin have been enriched in granitic magmas through fractionation, and low oxygen fugacity conditions have promoted the accumulation and transportation of W-Sn in the hydrothermal fluids, leading to deposition of mineral phases. The geochemical data suggest that Piaoac granites formed in an extensional setting related with the Late Cretaceous magmatism occurring large-scale lithospheric extensional in South China Block.

关键词： geochemistry zircon U-Pb age Hf isotope Piaoac granite W-Sn mineralization Northern Vietnam

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Defect engineering of water-dispersible g-C_(3)N_(4) photocatalysts by chemical oxidative etching of bulk g-C_(3)N_(4) prepared in different calcination atmospheres

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Journal of Materials Science & Technology 2022年第8期103卷 232-243页

作者： Thi Kim anh nguyen Thanh-Truc Pham Bolormaa Gendensuren Eun-Suok Oh Eun Woo Shin School of Chemical Engineering University of UlsanDaehakro 93Ulsan 44610South Korea Department of Material Technology Faculty of Applied ScienceHo Chi Minh City University of Technology and Education(HCMUTE)No.1 Vo Van Ngan StreetLinh Chieu WardThu Duc DistrictHo Chi Minh City 700000Viet Nam

In this study,water-dispersible graphitic carbon nitride(g-C_(3)N_(4))photocatalysts were successively prepared through the chemically oxidative etching of bulk g-C_(3)N_(4) that was polymerized thermally in different calcination atmospheres such as air,CO_(2),and N_(2).The different calcination atmospheres directly influenced the physicochemical and optical properties of both bulk and water-dispersible g-C_(3)N_(4),changing the photocatalytic degradation behavior of methylene blue(MB)and tetracycline hydrochloride(TCHCl)for water-dispersible g-C_(3)N_(4).The bubble-burst process in the thermal polymerization of thiourea produced defective edges containing C=O groups that preferred substituting the C-NHx groups over bulk g-C_(3)N_(4).In the oxygen-free N_(2) atmosphere among the different calcination atmospheres,more C=O functional groups were generated on the defective edges of bulk g-C_(3)N_(4),resulting in the highest N vacancy of the tri-s-triazine *** the successive chemical oxidation,S-or O-containing functional groups were introduced onto water-dispersible g-C_(3)N_(4).The water-dispersible g-C_(3)N_(4) photocatalyst from the oxygen-free N_(2) atmosphere(NTw)contained the most O-and S-functional groups on the g-C_(3)N_(4) ***,NTw exhibited the highest photocatalytic activity in the MB and TC-HCl photodegradation because of its slowest recombination process,which was ascribed to the unique surface properties of NTw such as abundant functional groups on the defective edges and N-deficient property.

关键词： g-C_(3)N_(4) Water-dispersible photocatalyst Calcination atmosphere Charge separation Chemically oxidative etching Defect edges

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A fully automated framework for helicopter rotor blades design and analysis including aerodynamics,structure, and manufacturing

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Chinese Journal of Aeronautics 2016年第6期29卷 1602-1617页

作者： Ngoc anh Vu Jae Woo Lee Tuan Phuong Nam Le Song Thanh Thao nguyen Division of Computational Mechatronics Institute for Computational Science Ton Duc Thang University Faculty of Electrical & Electronics Engineering Ton Duc Thang University Department of Aerospace Information Engineering Konkuk University Faculty of Mechanical Engineering Industrial University of Ho Chi Minh City Department of Aerospace Engineering Ho Chi Minh City University of Technology Vietnam National University-Ho Chi Minh City

This study describes an integrated framework in which basic aerospace engineering aspects(performance, aerodynamics, and structure) and practical aspects(configuration visualization and manufacturing) are coupled and considered in one fully automated design optimization of rotor blades. A number of codes are developed to robustly perform estimation of helicopter configuration from sizing, performance analysis, trim analysis, to rotor blades configuration representation. These codes are then integrated with a two-dimensional airfoil analysis tool to fully design rotor blades configuration including rotor planform and airfoil shape for optimal aerodynamics in both hover and forward flights. A modular structure design methodology is developed for realistic composite rotor blades with a sophisticated cross-sectional geometry. A D-spar cross-sectional structure is chosen as a baseline. The framework is able to analyze all realistic inner configurations including thicknesses of D-spar, skin, web, number and ply angles of layers of each composite part,and materials. A number of codes and commercial software(ANSYS, Gridgen, VABS, Pre VABS,etc.) are implemented to automate the structural analysis from aerodynamic data processing to sectional properties and stress analysis. An integrated model for manufacturing cost estimation ofcomposite rotor blades developed at the Aerodynamic Analysis and Design Laboratory(AADL),Aerospace Information Engineering Department, Konkuk University is integrated into the framework to provide a rapid and dynamic feedback to configuration design. The integration of three modules has constructed a framework where the size of a helicopter, aerodynamic performance analysis, structure analysis, and manufacturing cost estimation could be quickly investigated. All aspects of a rotor blade including planform, airfoil shape, and inner structure are considered in a multidisciplinary design optimization without an exception of critical configuration.

关键词： Design optimization Helicopter rotor blades Integrated framework Modular structure design methodology Perform estimation

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On the speed of convergence of Picard iterations of backward stochastic differential equations

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Probability, Uncertainty and Quantitative Risk 2022年第2期7卷 133-150页

作者： Martin Hutzenthaler Thomas Kruse Tuan anh nguyen Faculty of Mathematics University of Duisburg-EssenThea-Leymann-Str.9EssenNordrhein-Westfalen 45127Germany Institute of Mathematics University of GiessenArndtstraβe 2Giessen 35392Germany

It is a well-established fact in the scientific literature that Picard iterations of backward stochastic differential equations with globally Lipschitz continuous nonlinearities converge at least exponentially fast to the *** this paper we prove that this convergence is in fact at least square-root factorially *** show for one example that no higher convergence speed is possible in ***,if the nonlinearity is zindependent,then the convergence is even factorially *** we reveal a phase transition in the speed of convergence of Picard iterations of backward stochastic differential equations.

关键词： Backward stochastic differential equation Picard iteration A priori estimate Semilinear parabolic partial differential equation

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A novel finite element formulation for static bending analysis of functionally graded porous sandwich plates

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Frontiers of Structural and Civil Engineering 2022年第12期16卷 1599-1620页

作者： van Chinh nguyen Trung Thanh TRAN Trung nguyen-THOI Quoc-Hoa PHAM Faculty of Mechanical Engineering Le Quy Don Technical UniversityHanoiVietnam Laboratory for Applied and Industrial Mathematics Institute for Computational Science and Artificial IntelligenceVan Lang UniversityHo Chi Minh CityVietnam Faculty of Mechanical-Electrical and Computer Engineering Van Lang UniversityHo Chi Minh CityVietnam Faculty of Engineering and Technology Nguyen Tat Thanh UniversityHo Chi Minh CityVietnam

This article aims to propose a finite element formulation based on Quasi-3D theory for the static bending analysis of functionally graded porous(FGP)sandwich *** FGP sandwich plates consist of three layers including the bottom skin of homogeneous metal,the top skin of fully ceramic and the FGP core layer with uneven porosity distribution.A quadrilateral(Q4)element with nine degrees of freedom(DOFs)per node is derived and employed in analyzing the static bending response of the plate under uniform and/or sinusoidally distributed *** accuracy of the present finite element formulation is verified by comparing the obtained numerical results with the published results in the ***,some numerical examples are performed to examine the effects of the parameters including power-law index k and porosity coefficient on the static bending response of rectangular FGP sandwich *** addition,a problem with a complicated L-shape model is conducted to illustrate the superiority of the proposed finite element method.

关键词： sandwich plates functionally graded porous static bending Quasi-3D theory Q4 element

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Isogeometric analysis for free vibration of bidirectional functionally graded plates in the fluid medium

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Defence Technology（防务技术） 2022年第8期18卷 1311-1329页

作者： Quoc-Hoa Pham Phu-Cuong nguyen van Ke Tran Trung nguyen-Thoi Faculty of Civil Engineering Ho Chi Minh City Open UniversityHo Chi Minh CityViet Nam Faculty of Mechanical Engineering Le Quy Don Technical UniversityHanoiViet Nam Division of Computational Mathematics and Engineering Institute for Computational ScienceTon Duc Thang UniversityHo Chi Minh CityViet Nam Faculty of Civil Engineering Ton Duc Thang UniversityHo Chi Minh CityViet Nam

This paper for first time proposes an isogeometric analysis (IGA) for free vibration response of bi-directional functionally graded (BDFG) rectangular plates in the fluid medium. Material properties of the BDFG plate change in both the thickness and length directions via power-law distributions and Mori-Tanaka model. The governing equation of motion of BDFG plate in the fluid-plate system is formulated basing on Hamilton's principle and the refined quasi three-dimensional (3D) plate theory with improved function f(z). The fluid velocity potential is derived from the boundary conditions of the fluid-plate system and is used to determine the added mass. The discrete system of equations is derived from the Galerkin weak form and numerically analyzed by IGA. The accuracy and reliability of the proposed solutions are verified by comparing the obtained results with those published in the literature. Moreover, the effects of the various parameters such as the interaction boundary condition, geometric parameter, submerged depth of plate, fluid density, fluid level, and the material volume control coefficients on the free vibration behavior of BDFG plate in the fluid medium are investigated in detail. Some major findings regarding the numerical results are withdrawn in conclusions.

关键词： Contact plate-fluid Refined quasi 3D plate theory Mori-Tanaka model Isogeometric analysis Bidirectional functionally graded plate

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CONVERGENCE RESULTS FOR NON-OVERLAP SCHWARZ WAVEFORM RELAXATION ALGORITHM WITH CHANGING TRANSMISSION CONDITIONS

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Acta Mathematica Scientia 2022年第1期42卷 105-126页

作者： Minh-Phuong TRAN Thanh-Nhan nguyen Phuoc-Toan HUYNH Nhu-Binh LY Minh-Dang nguyen Quoc-anh HO Applied Analysis Research Group Faculty of Mathematics and StatisticsTon Duc Thang UniversityHo Chi Minh cityVietnam Department of Mathematics Ho Chi Minh City University of EducationHo Chi Minh cityVietnam Faculty of Mathematics and Statistics Ton Duc Thang UniversityHo Chi Minh cityVietnam

In this paper,we establish a new algorithm to the non-overlapping Schwarz domain decomposition methods with changing transmission conditions for solving one dimensional advection reaction diffusion *** precisely,we first describe the new algorithm and prove the convergence results under several natural assumptions on the sequences of parameters which determine the transmission *** we give a simple method to estimate the new value of parameters in each *** interesting advantage of our method is that one may update the better parameters in each iteration to save the computational cost for optimizing the parameters after many *** some numerical experiments are performed to show the behavior of the convergence rate for the new method.

关键词： domain decomposition method Schwarz waveform relaxation algorithm advection reaction diffusion changing transmission conditions

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Static analysis of corrugated panels using homogenization models and a cell-based smoothed mindlin plate element (CS-MIN3)

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Frontiers of Structural and Civil Engineering 2019年第2期13卷 251-272页

作者： Nhan nguyen-MINH Nha TRAN-van Thang BUI-XUAN Trung nguyen-THOI Faculty of Applied Science Bach Khoa University (BKU)Ho Chi Minh CityVietnam Faculty of Mathematics and Computer Science Ho Chi Minh City University of Science (HCMUS)Ho Chi Minh CityVietnam Department of Mathematics L ouisiana State UniversityBaton RougeLA 70803USA Division of Computational Mathematics and Engineering Institute of Computational ScienceTon Due Thang UniversityHo Chi Minh CityVietnam Faculty of Civil Engineering Ton Due Thang UniversityHo Chi Minh CityVietnam

Homogenization is a promising approach to capture the behavior of complex structures like corrugated panels. It enables us to replace high-cost shell models with stiffness-equivalent orthotropic plate alternatives. Many homogenization models for corrugated panels of different shapes have been proposed. However, there is a lack of investigations for verifying their accuracy and reliability. In addition, in the recent trend of development of smoothed finite element methods, the cell-based smoothed three-node Mindlin plate element (CS-MIN3) based on the first-order shear deformation theory (FSDT) has been proposed and successfully applied to many analyses of plate and shell structures. Thus, this paper further extends the CS-MIN3 by integrating itself with homogenization models to give homogenization methods. In these methods, the equivalent extensional, bending, and transverse shear stiftriess components which constitute the equivalent orthotropic plate models are represented in explicit analytical expressions. Using the results of ANSYS and ABAQUS shell simulations as references, some numerical examples are conducted to verify the accuracy and reliability of the homogenization methods for static analyses of trapezoidally and sinusoidally corrugated panels.

关键词： homogenization corrugated panel asymptotic analysis smoothed finite element method (S-FEM) cell-based smoothed three-node Mindlin plate element (CS-MIN3)

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Xanthine oxidase inhibitors from Archidendron clypearia(Jack.) I.C. Nielsen: Results from systematic screening of Vietnamese medicinal plants

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Asian Pacific Journal of Tropical Medicine 2017年第6期10卷 619-626页

作者： nguyen Thuy Duong Pham Duc Vinh Phuong Thien Thuong nguyen Thi Hoai Le nguyen Thanh Tran The Bach nguyen Hai Nam nguyen Hoang anh Department of Pharmacology Hanoi University of Pharmacy Department of Pharmaceutical Analysis and Standardization National Institute of Medicinal Materials Department of Pharmacognosy Hue University of Medicine and Pharmacy Institute of Marine Biochemistry Vietnam Academy of Science and Technology Institute of Ecology and Biological Resources Vietnam Academy of Science and Technology Department of Medicinal Chemistry Hanoi University of Pharmacy

Objective: To screen Vietnamese medicinal plants for xanthine oxidase(XO) inhibitory activity and to isolate XO inhibitor(s) from the most active plant. Methods: The plants materials were extracted by methanol. The active plant materials were fractionated using different organic solvents, including n-hexane, ethyl acetate, and n-butanol. Bioassay-guided fractionation and column chromatography were used to isolate compounds. The compounds structures were elucidated by analysis of spectroscopic data, including IR, MS, and NMR. Results: Three hundreds and eleven methanol extracts(CME) belonging to 301 Vietnamese herbs were screened for XO inhibitory activity. Among these plants, 57 extracts displayed XO inhibitory activity at 100 μg/m L with inhibition rates of over 50%. The extracts of Archidendron clypearia, Smilax poilanei, Linociera ramiflora and Passiflora foetida exhibited the greatest potency with IC_(50) values below 30 μg/m L. Chemical study performed on the extract of Archidendron clypearia resulted in the isolation of six compounds, including 1-octacosanol, docosenoic acid, daucosterol, methyl gallate, quercitrin and(-)-7-O-galloyltricetiflavan. The compound(-)-7-O-galloyltricetiflavan showed the most potent XO inhibitory activity with an IC_(50) value of 25.5 μmol/L. Conclusions: From this investigation, four Vietnamese medicinal plants were identified to have XO inhibitory effects with IC_(50) values of the methanol extracts below 30 μg/m L. Compound(-)-7-O-galloyltricetiflavan was identified as an XO inhibitor from Archidendron clypearia with IC_(50) value of 25.5 μmol/L.

关键词： Xanthine oxidase Inhibitor Medicinal plants Vietnam

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Effective Evaluation of Using PIDOTIMOD in Treatment of Refractory Allergic Rhinitis

Effective Evaluation of Using PIDOTIMOD in Treatment of Refr...

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作者： Mai nguyen Quynh anh 大连医科大学

学位级别：硕士

目的观察匹多莫德对难治性过敏性鼻炎的治疗作用。方法研究以2019年8月至2020年8月期间于大连医科大学附属第一医院耳鼻喉科门诊诊断难治性过敏性鼻炎的68名患者为研究对象。患者随机分为两组,实验组和对照组。所有患者在治疗前均填写... 详细信息

目的观察匹多莫德对难治性过敏性鼻炎的治疗作用。方法研究以2019年8月至2020年8月期间于大连医科大学附属第一医院耳鼻喉科门诊诊断难治性过敏性鼻炎的68名患者为研究对象。患者随机分为两组,实验组和对照组。所有患者在治疗前均填写症状评分问卷,并进行鼻内窥镜检查,对鼻甲肿胀程度和鼻部分泌物情况进行评分。对照组患者给予口服抗组胺药和鼻喷布地奈德治疗;实验组患者在常规治疗基础上额外给予匹多莫德40mg,日两次口服。对比两组治疗前、治疗后两周、治疗后四周鼻部症状评分和鼻内窥镜检查评分评估匹多莫德治疗难治性过敏性鼻炎的临床效果。两组间比较采用配对T检验和Winconxon符号秩检验。结果治疗前对照组鼻部症状评分在鼻塞、流涕、鼻部刺痒感和喷嚏的得分分别是3.31±0.693,3.25±0.672,3.44±0.716,和 3.19±0.53;实验组分别是 3.22±0.659,2.75±0.672,3.16±0.723和2.94±0.669。两组之间差异无统计学意义(P>0.05)。鼻内窥镜下下鼻甲肿胀和鼻分泌物量评分在对照组分别是1.81±0.397,和2.69±0.471,实验组分别是1.84±0.369和2.47±0.621,差异无统计学意义(P>0.05)。治疗后两周对照组鼻部症状评分在鼻塞、流涕、鼻部刺痒感和喷嚏的得分分别是 2.94±0.669,2.81±0.644,2.75±0.762,和 2.44±0.504。实验组鼻部症状评分分别是 1.13±0.751,1.19±0.965,1.03±0.822,和 1.03±0.782。实验组较对照组在上述症状分别多下降1.81±0.082(61.56%),1.62±0.321(57.65%),1.72±0.06(62.54%),和1.41±0.278(57.78%),两组间比较,差异有统计学意义(P<0.05)。对照组鼻内窥镜下下鼻甲肿胀和鼻分泌物量评分分别是1.44±0.504和2.13±0.609;实验组分别是0.53±0.507和0.91±0.777,实验组下鼻甲肿胀和鼻内分泌物评分比对照组分别降低0.91±0.003(63.19%)和1.22±0.168(57.27%),两组对比差异有统计学意义(P<0.05)。治疗4周后对照组鼻塞、流涕、鼻部刺痒感和喷嚏的症状评分是0.47±0.507,0.50±0.508,0.44±0.564,和0.34 ± 0.483。实验组症状改善更多,比对照组减低1.84±0.186(79.65%),1.44±0.161(74.22%),1.69±0.143(79.34%),和 1.41±0.189(80.57%),差异有统计学意义(P<0.05)。对照组鼻内窥镜评分分别是1.19±.644和2.00±0.508,实验组评分分别为0.06±0.246和0.19±0.397,两组对比,实验组下鼻甲肿胀和鼻内分泌物评分比对照组分别降低1.13±0.398(94.95%)和1.81±0.111(90.5%)(P<0.05)。结论匹多莫德可以提高机体免疫力,辅助抗组胺药和鼻喷激素应用可以快速控制难治性过敏性鼻炎的临床症状和体征。

关键词：过敏性鼻炎过敏原免疫治疗匹多莫德

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