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Random vibration analysis of FGM plates subjected to moving load using a refined stochastic finite element method

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Defence Technology（防务技术） 2024年第4期34卷 42-56页

作者： Ngoc-Tu do Trung thanh Tran Faculty of Mechanical Engineering Hanoi University of IndustryHanoiViet Nam Faculty of Mechanical Engineering Le Quy Don Technical UniversityHanoiViet Nam

The article introduces a finite element procedure using the bilinear quadrilateral element or four-node rectangular element(namely Q4 element) based on a refined first-order shear deformation theory(rFSDT) and Monte Carlo simulation(MCS), so-called refined stochastic finite element method to investigate the random vibration of functionally graded material(FGM) plates subjected to the moving *** advantage of the proposed method is to use r-FSDT to improve the accuracy of classical FSDT, satisfy the stress-free condition at the plate boundaries, and combine with MCS to analyze the vibration of the FGM plate when the parameter inputs are random quantities following a normal distribution. The obtained results show that the distribution characteristics of the vibration response of the FGM plate depend on the standard deviation of the input parameters and the velocity of the moving ***, the numerical results in this study are expected to contribute to improving the understanding of FGM plates subjected to moving loads with uncertain input parameters.

关键词： FGM Moving load R-FSDT Q4 element Monte Carlo simulation Random vibration

High-temperature corrosion of sintered RE_(2)Si_(2)O_(7)(RE=Yb and Ho)environmental barrier coating materials by volcanic ash

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International Journal of Minerals,Metallurgy and Materials 2024年第7期31卷 1628-1638页

作者： Ayahisa Okawa Son thanh Nguyen Tadachika Nakayama thi-Mai-Dung do Hisayuki Suematsu Shu Yin Takuya Hasegawa Tsuneo Suzuki Takashi Goto Koichi Niihara Institute of Multidisciplinary Research for Advanced Materials Tohoku UniversitySendai 980-8577Japan Department of Creative Engineering National Institute of TechnologyKushiro 084-0916Japan Extreme Energy-Density Research Institute Nagaoka University of TechnologyNagaoka 940-2188Japan Advanced Institute for Materials Research(WPI-AIMR) Tohoku UniversitySendai 980-8577Japan

Rare-earth silicates are promising environmental barrier coatings(EBCs)that can protect SiC_(f)/Si C_(m)substrates in next-genera tion gas turbine ***,RE_(2)Si_(2)O_(7)(RE=Yb and Ho)shows potential as an EBC due to its coefficient of thermal expansion(CTE)compatible with substrates and high resistance to water vapor *** target operating temperature for next-generation tur bine blades is 1400°*** is inevitable during adhesion to molten volcanic ash,and thus,understanding the corrosion behavior o the material is crucial to its *** study investigates the high-temperature corrosion behavior of sintered RE_(2)Si_(2)O_(7)(RE=Yb and Ho).Samples were prepared using a solid-state reaction and hot-press *** were then exposed to volcanic ash at 1400°C for 224,and 48 *** 48 h of exposure,volcanic ash did not react with Yb_(2)Si_(2)O_(7)but penetrated its interior,causing *** Ho_(2)Si_(2)O_(7)was partially dissolved in the molten volcanic ash,forming a reaction zone that prevented volcanic ash melts from penetrating the *** increasing heat treatment time,the reaction zone expanded,and the thickness of the acicular apatite grains increased The Ca:Si ratios in the residual volcanic ash were mostly unchanged for Yb_(2)Si_(2)O_(7)but decreased considerably over time for Ho_(2)Si_(2)O_(7).Th Ca in volcanic ash was consumed and formed apatite,indicating that RE^(3+)ions with large ionic radii(Ho>Yb)easily precipitated apatit from the volcanic ash.

关键词： environmental barrier coating volcanic ash rare-earth disilicate corrosion

Some Mean Convergence Theorems for the Maximum of Normed double Sums of Banach Space Valued Random Elements

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Acta Mathematica Sinica,English Series 2024年第7期40卷 1727-1740页

作者： Andrew ROSALSKY Le Van thanh Nguyen thi THUY Department of Statistics University of FloridaGainesvilleFL 32611-8545USA Department of Mathematics Vinh UniversityVinhNghe AnViet Nam High School for Gifted Students Vinh UniversityVinhNghe AnViet Nam

In this correspondence,we establish mean convergence theorems for the maximum of normed double sums of Banach space valued random *** of the results pertain to random elements which are *** expand and improve a number of particular cases in the literature on mean convergence of random elements in Banach *** of the main contributions of the paper is to simplify and improve a recent result of Li,Presnell,and Rosalsky[Journal of Mathematical Inequalities,16,117–126(2022)].A new maximal inequality for double sums of M-dependent random elements is proved which may be of independent *** sharpness of the results is illustrated by four examples.

关键词： double sum mean convergence Rademacher type p Banach space Banach space valued random element M-dependent random elements

Integrated strategies on cobalt phosphides-based electrocatalysts for efficient hydrogen evolution reaction

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Tungsten 2024年第3期6卷 488-503页

作者： thanh Dam Mai Ha Huu do Faculty of Mechanical Engineering and Technology Ho Chi Minh City University of Industry and Trade VKTech Research Center NTT Hi-Tech Institute Nguyen Tat Thanh University

The development of cost-effective and durable hydrogen evolution reaction(HER) electrocatalysts plays a vital role in dealing with the issues related to carbon dioxide *** phosphide-based nanomaterials are evaluated as promising advocates for HER due to high catalytic activities,good stability,and rich *** review commences with an exploration of the synthetic pathways of CoP,including solid-phase,solution-phase along with electrochemical ***,the mechanism of hydrogen formation is expressed thoroughly,after which various integrated strategies of morphology engineering with doping,assisted highly conductive materials,and construction of heterostructure were introduced for ***,burdensome tasks and possible guidance for the advancement of CoP-based nanomaterials were discussed for hydrogen production.

关键词： Cobalt phosphides Nanomaterials Electrocatalysts Hydrogen evolution reaction

Prevalence and risk factors associated with long COVID symptoms in children and adolescents in a southern province of Vietnam

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Asian Pacific Journal of Tropical Medicine 2024年第3期17卷 119-128,I0001,I0002页

作者： Huynh Ngoc Linh Nguyen The Tan Le thi Minh Thu Nguyen Tu Loan Nguyen thi To Uyen Le thanh Thao Trang Truong thanh Nam doan Hoang Phu Faculty of Medicine Ca Mau Medical CollegeCa Mau 98000Vietnam Ca Mau Obstetrics and Pediatrics Hospital Ca Mau 98000Vietnam Faculty of Basic Science and Public Health Dong Thap Medical CollegeDong Thap 81000Vietnam Graduate University of Sciences and Technology Vietnam Academy of Science and TechnologyHa Noi 10000Vietnam Community Public Health Research Program School of Public HealthWalailak UniversityNakhon Si Thammarat 80160Thailand Faculty Public Health Can Tho University of Medicine and PharmacyCan Tho City 94000Vietnam doctoral Program in Health Sciences College of Graduate StudiesWalailak UniversityNakhon Si Thammarat 80160Thailand

Objective:To investigate the prevalence and risk factors associated with long COVID symptoms among children and adolescents who have recovered from ***:this study applied a cross-sectional approach within community settings in a southern province of Vietnam.A structured questionnaire featuring socio-demographic information and common long COVID symptoms was *** correlation coefficients assessed associations among pairs of long COVID ***,multivariable logistic regression models were performed to investigate the risk factors of long COVID in recovered COVID-19 children and ***:Among 422 participants,39.3%reported long COVID symptoms,with a prevalence of 45.2%(SD=0.5)in children and 22.2%(SD=0.4)in *** symptoms reported were cough 34.6%(SD=0.5),fatigue 20.6%(SD=0.4),shortness of breath 10.9%(SD=0.3),and lack of appetite 6.6%(SD=0.3).Concerning risk factors of long COVID,a higher risk was observed among demographic groups,including girls(OR 1.25,95%CI 1.15-1.37;Pdolescents(OR 1.24,95%CI 1.12-1.37;Pdose(OR 1.35,95%CI 1.10-1.64;P=0.004)compared to those who have received two ***,patients with a COVID-19 treatment duration exceeding two weeks also had a higher risk of long COVID(OR 1.32,95%CI 1.09-1.60;P=0.003)than those who recovered less than seven ***:The insights from this study provide crucial guidance for predicting the factors associated with the occurrence of long COVID in pediatric patients,contributing to strategic interventions aimed at mitigating the long COVID risks among children and adolescents in Vietnam.

关键词： Long COVID Prevalence Risk factors Children Adolescent Vietnam

Comparative Chemical Research in Essential Oils from Six Apiaceae Species Growing in the Northern Region of Vietnam

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Phyton-International Journal of Experimental Botany 2024年第7期93卷 1677-1687页

作者： Nguyen Quang Hung Nguyen thanh Tung Nguyen Phuong Hanh Chu thi Thu Ha Nguyen thi Nhung Nguyen Thai An Vu Xuan Giang Luong Van Hao Oleh Koshovyi Ain Raal Institute of Ecology and Biological Resources Vietnam Academy of Science and Technology(VAST)Cau GiayHa Noi100000Viet Nam Graduate University of Science and Technology Vietnam Academy of Science and Technology(VAST)Cau GiayHa Noi100000Viet Nam Department of Pharmacognosy Faculty of Pharmacognosy and Traditional MedicineHanoi University of PharmacyHoan KiemHa Noi100000Viet Nam Sa Pa Research Center of Medicinal Materials National Institute of Medicinal MaterialsDien Bien PhuSa PaLao Cai330000Viet Nam Institute of Pharmacy Faculty of MedicineUniversity of TartuTartu50411Estonia

Our study aimed to compare the essential oil(EO)concentration and composition of several Apiaceae species growing in the Northern region of *** yields of EOs from materials ranged from 0.03%(root EO of Angelica acutiloba and aerial parts EO of Heracleum bivittatum)-0.27%(leaf EO of Xyloselinum vietnamense).Gas chromatography-mass spectrometry(GC-MS)allowed the identiﬁcation of 74 components in the EOs of six Apiaceae species,making up 94.4%–100.0%of the *** EO from Angelica acutiloba,(Z)-ligustilide accounted for an extremely large proportion(94.9%).EO of Angelica pubescens was dominated by six character-istic components includingα-pinene(21.5%),β-phellandrene(18.1%),p-cymene(12.2%),3-methylnonane(8.7%),o-cymene(8.1%),and D-sylvestrene(6.2%).The EO from Cryptotaenia japonica was characterized by high amounts ofα-selinene(48.7%),β-selinene(23.7%),and trans-β-farnesene(5.4%).The EOs from leaves and stems of Xyloselinum vietnamense were characterized by high concentrations of sabinene(69.8%and 33.8%),4-terpineol(8.7%and 7.4%)andβ-pinene(4.0%and 6.5%)while EOs from aerial parts and root of Xylo-selinum leonidii comprise four characteristic monoterpenes includingα-pinene(28.2%and 52.8%),β-pinene(7.9%and 10.3%),β-phellandrene(7.6%and 15.3%),and sabinene(3.0%and 4.1%).Additionally,cryptone is also one of the major components in the EO of Xyloselinum leonidii(13.2%in the aerial parts oil and 2.8%in the root oil).In the EOs isolated from the aerial parts and root of Heracleum bivittatum,α-pinene(22.5%and 70.2%)andβ-pinene(43.2%and 20.0%)were the predominant *** appeared in the EO from aerial parts of Heracleum bivittatum with a relatively high concentration(13.5%)while bornyl acetate(5.1%)was also one of the main components in the EO from its aerial parts but was not detected in other Apiaceae species in the present *** databases help identify and control the quality of plant material studied from the family Apiaceae growing in Vietnam.

关键词： Apiaceae essential oil terpenoids gaschromatography-mass spectrometry

SWIR FluorescenceImaging In Vivo Monitoring and Evaluating Implanted M2 Macrophages in Skeletal Muscle Regeneration

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Engineering 2024年第2期33卷 283-294页

作者： Mo Chen Yuzhou Chen Sijia Feng Shixian dong Luyi Sun Huizhu Li Fuchun Chen Nguyen thi Kim thanh Yunxia Li Shiyi Chen You Wang Jun Chen Sports Medicine Institute of Fudan University Department of Sports MedicineHuashan HospitalFudan UniversityShanghai 200040China Department of Bone and Joint Surgery Department of OrthopedicsRenji HospitalSchool of MedicineShanghai Jiaotong UniversityShanghai 200127China Department of Anatomy and Physiology School of MedicineShanghai Jiao Tong UniversityShanghai 200025China Key Laboratory of Infrared System Detection&Imaging Technology Shanghai Institute of Technical PhysicsChinese Academy of SciencesShanghai 200083China Biophysics Group Department of Physics and AstronomyUniversity College LondonLondon WC1E 6BTUK Healthcare Biomagnetic and Nanomaterials Laboratories University College LondonLondon W1S 4BSUK

Skeletal muscle has a robust regeneration ability that is impaired by severe injury,disease,and *** in a decline in skeletal muscle ***,improving skeletal muscle regeneration is a key challenge in treating skeletal muscle-related *** to their significant role in tissue regeneration,implantation of M2 macrophages(M2MФ)has great potential for improving skeletal muscle ***,we present a short-wave infrared(SWIR)fluorescence imaging technique to obtain more in vivo information for an in-depth evaluation of the skeletal muscle regeneration effect after M2MФ*** fluorescence imaging was employed to track implanted M2MФin the injured skeletal muscle of mouse *** is found that the implanted M2MФaccumulated at the injury site for two ***,SWIR fluorescence imaging of blood vessels showed that M2MФimplantation could improve the relative perfusion ratio on day 5(1.09±0.09 vs 0.85±0.05;p=0.01)and day 9(1.38±0.16 vs 0.95±0.03;p=0.01)post-injury,as well as augment the degree of skeletal muscle regencration on day 13 ***,multiple linear regression analyses determined that post-injury time and relative perfusion ratio could be used as predictive indicators to evaluate skeletal muscle *** results provide more in vivo details about M2MФin skeletal muscle regeneration and confirm that M2MФcould promote angiogenesis and improve the degree of skeletal muscle repair,which will guide the research and development of M2MФimplantation to improve skeletal muscle regeneration.

关键词： In vivo Short-wave infrared Skeletal muscle Macrophage Regeneration

Influence of different land-use types on selected soil properties related to soil fertility in A Luoi District,Thua thien Hue,Vietnam

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Soil Ecology Letters 2024年第1期6卷 131-140页

作者： Khoa Phuc Nguyen Tan Trong Tran Huy Dinh Le Phuong Thuy Nguyen Hien Thao thi Pham Dien thanh Nguyen Ngu Huu Nguyen University of Agriculture and Forestry Hue UniversityHue CityThua Thien Hue 52000Vietnam School of Biotechnology Tan Tao UniversityTan Duc ECityDuc HoaLong An850000Vietnam

Land use type affects the physicochemical properties of *** value of OM and TN is high in acacia *** acidity of soil is considered a serious constraint for *** cash crops are acacia,cassava,banana,rice and *** fertility is affected by land-use types and land management,which exacerbates soil erosion and various other forms of soil degradation in the mountainous regions of *** study was conducted in A Luoi District,Thua thien Hue,Vietnam to identify the effects of land-use types on specific soil physicochemical characteristics related to soil *** physicochemical properties,such as organic matter(OM),total nitrogen(TN),total phosphorous(TP),and K+were significantly affected by land-use *** results showed that the soils were sandy in rice but clay loam for acacia and *** mean bulk density value of acacia soil was significantly greater than that of other *** were higher in the acacia soils than those in the rice,maize,and banana *** OM content was significantly higher in the acacia,cassava,and banana soils than those in the rice and maize *** mean of exchangeable K+in the rice soil was higher compared to those in other soils and was affected by land-use *** high exchangeable acidity content in the soils was probably due to intensive ***,both land use type and management did not affect the CEC ***,the inappropriate land use caused the disturbance of soil physicochemical properties,indicating that the conditions of rice and maize soils are becoming worse than acacia ***,lowering the intensity of cultivation,adopting incorporated soil fertility management,and applying organic fertilizer should preserve the existing conditions and enhance soil properties.

关键词： Land-use types soil characteristics soil frility suitable crop Vietnam

初中级越南汉语学习者状态补语习得偏误研究及建议 ——以胡志明市师范大学中文系为例

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初中级越南汉语学习者状态补语习得偏误研究及建议 ——以胡志明...

作者：陈氏清草（Tran thi thanh Thao）河北大学

学位级别：硕士

补语是中文语法中的一个重要知识点,也是一个相对难的语法学习点,特别是对于越南学习者,因为在越南语中没有相似的结构,所以对于他们来说补语的难度更大。中文有着丰富而复杂的补语系统,其中,状态补语在汉语中使用频率高、结构复杂、语... 详细信息

补语是中文语法中的一个重要知识点,也是一个相对难的语法学习点,特别是对于越南学习者,因为在越南语中没有相似的结构,所以对于他们来说补语的难度更大。中文有着丰富而复杂的补语系统,其中,状态补语在汉语中使用频率高、结构复杂、语义繁多、语境因素强,被汉语教学界视为汉语教学的重点和难点。笔者是越南留学习者,也曾经经历过汉语学习初中级这段时间,因此特别理解初中级汉语学习者习得过程中的困难与学习过程中的需求。本文主要收集了越南胡志明市师范大学中文系初中级汉语学习者在使用汉语状态补语时产生的偏误,并进行了详细的偏误研究和分析。通过调查与分析,笔者旨在找出更科学有效的汉语状态补语教学方法。本文先对研究背景、研究目的和意义、研究方法等进行说明,对状态补语的语料搜集情况进行概述,本文选择《HSK标准教材2、3》中的状态补语为考察对象,以偏误分析理论、中介语理论和对比分析理论为指导,并采用调查分析、个别访谈等方法进行研究。其次对国际中文教学中的状态补语进行研究综述与相关界定,主要总结了状态补语的本体研究和国际中文教学中的状态补语研究,分析了状态补语研究现状。笔者还对初中级越南学习者的调查问卷和试题进行整理和分析,主要针对胡志明市师范大学中文系的初中级学习者,通过调查问卷与访谈进行状态补语偏误语料的搜集与统计。第四部分对初中级越南学习者学习状态补语的偏误进行了分类,共分为五类。随后,对初中级越南学习者学习汉语状态补语产生偏误的原因进行了分析,分为客观因素和主观因素,并探讨了学习者们回避状态补语学习的现象及其原因。最后是对状态补语的教学思考,针对引起偏误的原因提出具体的教学建议,并设计了部分教学计划,同时提供了《HSK标准教程1、2、3》中状态补语动词相关的参考例句和练习。希望本文研究成果能为越南初中级汉语语法教学提供启示,并能在实际教学中提高教学效果、降低学习难度、减轻教学压力,从而找到最佳的汉语状态补语教学途径。同时,也期望本研究能够为国际中文教学和研究贡献一份力量。

关键词：初中级越南学习者状态补语习得偏误