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化学絮凝结合真空预压处理的渤海湾海洋疏浚泥固结特性

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大连理工大学学报 2022年第6期62卷 626-632页

作者：陈国公武亚军许嘉乐李运红王攀秦荣荣 le thanh hai VU Quoc Vuong 上海大学土木工程系上海200444 中国冶金地质总局青岛地质勘查院山东青岛266109 越南胡志明市国立大学资源与环境研究院胡志明市740500越南越南水利大学土木工程学院河内116301越南

为了改善渤海湾海洋疏浚泥渗透性差和排水固结时间长的不足,引入化学絮凝结合真空预压的地基处理方法.首先分析了山东东营地区疏浚泥的矿物成分与物理性质,然后采用两种不同的絮凝剂进行了沉降柱试验与真空预压模型试验.结果表明:絮凝剂... 详细信息

为了改善渤海湾海洋疏浚泥渗透性差和排水固结时间长的不足,引入化学絮凝结合真空预压的地基处理方法.首先分析了山东东营地区疏浚泥的矿物成分与物理性质,然后采用两种不同的絮凝剂进行了沉降柱试验与真空预压模型试验.结果表明:絮凝剂APAM添加量越大,混液面沉降速度越快,在添加量为15%时速度最快,约5 min内沉降基本稳定;絮凝剂CaO添加量越大,混液面沉降速度越慢,当添加量越过某一值(10%)时,最终混液面基本保持不变;真空预压排水速率并非絮凝剂添加量越大越快,絮凝剂CaO添加量为0.6%时速率最快,絮凝剂APAM添加量为15%时速率最快.研究成果对于东营疏浚泥地基处理工程实践具有一定的指导意义.

关键词：渤海湾疏浚泥絮凝真空固结

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越南杧果产业发展趋势预测与启示

中国南方果树 2024年第4期53卷 251-258,264页

作者：邓志新 VU thanh hai 刘洋铭 PHAM Quang Thang 西南林业大学绿色发展研究院昆明650224 越南国立农业大学越南河内云南机电职业技术学院昆明650201 越南有机农业工艺研究院越南河内

近年来,中国已成为越南杧果出口主要目标市场。本文以越南杧果产业为研究对象,运用“全程质量支撑技术体系”理论,分析其杧果产业发展现状及关键技术约束集,预测越南杧果产业发展趋势,推测其对中国杧果产业近期、中期、长期的影响,提出... 详细信息

近年来,中国已成为越南杧果出口主要目标市场。本文以越南杧果产业为研究对象,运用“全程质量支撑技术体系”理论,分析其杧果产业发展现状及关键技术约束集,预测越南杧果产业发展趋势,推测其对中国杧果产业近期、中期、长期的影响,提出我国应对策略建议,助力我国杧果产业发展。

关键词：越南杧果产业全程质量支撑技术体系中国大青杧

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Atomistic simulation of free transverse vibration of graphene,hexagonal SiC, and BN nanosheets

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Acta Mechanica Sinica 2017年第1期33卷 132-147页

作者： Danh-Truong Nguyen Minh-Quy le thanh-Lam Bui hai-le Bui School of Mechanical Engineering Hanoi University of Science and Technology Hanoi 10000 Vietnam International Institute for Computational Science and Engineering Hanoi University of Science and TechnologyHanoi 10000 Vietnam Faculty of Mechanical Engineering Hanoi University of Industry Hanoi 10000 Vietnam

Free transverse vibration of monolayer graphene, boron nitride (BN), and silicon carbide (SiC) sheets is investigated by using molecular dynamics finite element method. Eigenfrequencies and eigenmodes of these three sheets in rectangular shape are studied with different aspect ratios with respect to various boundary conditions. It is found that aspect ratios and boundary conditions affect in a similar way on natural frequencies of graphene, BN, and SiC sheets. Natural frequencies in all modes decrease with an increase of the sheet’s size. Graphene exhibits the highest natural frequencies, and SiC sheet possesses the lowest ones. Missing atoms have minor effects on natural frequencies in this study.

关键词： Atomistic simulation Hexagonal sheet Transverse vibration Molecular dynamics finite element method

Nonlocal isogeometric analysis for bidirectional functionally graded porous curved microbeams with arbitrary boundary conditions

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Acta Mechanica Sinica 2024年第8期40卷 194-218页

作者： Thu-Huong Nguyen Thi Van Ke Tran Van-Minh Phung Van hai Trinh Quoc Hoa Pham Faculty of Mechanical Engineering Hanoi University of IndustryHanoi100000Vietnam Faculty of Mechanical Engineering Le Quy Don Technical UniversityHanoi100000Vietnam Institute of Vehicle and Energy Engineering Le Quy Don Technical UniversityHanoi100000Vietnam Faculty of Engineering and Technology Nguyen Tat Thanh UniversityHo Chi Minh City700000Vietnam

This research aims to analyze the static bending and free vibration behaviors of bidirectional functionally graded porous(BFGP)curved microbeams with elastic boundary conditions resting on a Pasternak’s elastic foundation in a hygro-thermal *** analysis based on non-uniform rational B-splines,first-order shear deformation theory,nonlocal elasticity theory combined with the modified strain gradient theories,modified Timoshenko beam theory are formulated to depict bending and shear deformations of BFGP curved ***,because using the modified Timoshenko beam theory,this study removes the requirement for a shear correction factor and describes shear stress by zero at the upper and lower cross-sectional sites of the BFGP curved *** from traditional boundary conditions,where the beginning and end positions of a curved beam are connected by an elastic system of straight and torsion *** allows for greater flexibility in controlling the stiffness of the springs to obtain arbitrary *** assess the accuracy and convergence of the proposed approach,validation numerical examples were conducted in the various examples.

关键词： Bidirectional functionally graded porous material Elastic boundary condition Isogeometric analysis Curved microbeams Nonlocal elasticity theory Modified strain gradient theory

Transfer learning for Disease Diagnosis from Myocardial Perfusion SPECT Imaging

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Computers, Materials & Continua 2022年第12期73卷 5925-5941页

作者： Phung Nhu hai Nguyen Chi thanh Nguyen thanh Trung Tran Trung Kien Institute of Information Technology AMSTHanoi11307Vietnam Department of Medical Equipment 108 Military Central HospitalHanoi11610Vietnam

Coronary artery disease(CAD)is one of the most common pathological conditions and the major global cause of *** perfusion imaging(MPI)using single-photon emission computed tomography(SPECT)is a non-invasive method and plays an essential role in diagnosing ***,there is currently a shortage of doctors who can diagnose using SPECT-MPI in developing countries,especially *** on deploying machine learning and deep learning in supporting CAD diagnosis has been noticed for a long ***,these methods require a large dataset and are therefore time-consuming and *** study aims to develop a cost-effective and high-performance CAD classification model to support doctors in these *** this paper,we propose a transfer learning framework for a multi-stage training process with different learning *** process consists of two training stages:a warming up stage in which all layers of a pre-trained model(on ImageNet dataset)are frozen;and a finetuning stage in which a small amount of the top layers are unfrozen and then retrained with a lower learning *** dataset for this study consists of the polar maps from 218 *** popular CNN-based pre-trained models have been investigated,and ResNet152V2-based model has obtained the highest performances with an accuracy of 95.5%,area under the receiver operating characteristic curve(AUC)score 0.932,sensitivity 94.4%,precision 96.4%,and F1-score 95.2%.These performances are competitive or even better than all state-of-the-art approaches in terms of classification accuracy and *** also apply the class activation mapping technique to help explain the model’s predictions and increase the model’s reliability,proving capable of assisting the SPECT image readers in the CAD diagnosis.

关键词： Coronary artery disease deep learning transfer learning SPECTMPI polar maps

A comparative analysis of weight-based machine learning methods for landslide susceptibility mapping in Ha Giang area

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Big Earth Data 2023年第4期7卷 1005-1034页

作者： thanh Trinh Binh thanh Luu Trang Ha Thi le Duong Huy Nguyen Trong Van Tran Thi hai Van Nguyen Khanh Quoc Nguyen Lien Thi Nguyen Faculty of Computer Science Phenikaa UniversityYen NghiaHa DongHanoi 12116Vietnam Phenikaa Research and Technology Institute(PRATI) A&A Green Phoenix Group JSCNo.167 Hoang NganTrung HoaCau GiayHanoi 11313Vietnam Northwestern Geological Division General Department of Geology and Minerals of VietnamHanoiVietnam Youth union office Thuyloi University175 Tay SonDong DaHanoiVietnam Center of Remote Sensing and Geohazards Vietnam Institute of Geosciences and Mineral ResourcesHanoiVietnam

Landslide susceptibility maps (LSMs) are very crucial for planningpolicies in hazardous areas. However, the accuracy and reliability ofLSMs depend on available data and the selection of suitable *** study is conducted to produce LSMs by combinations of machinelearning methods and weighting techniques for Ha Giang province,Vietnam, where has limited data. In study area, we gather 11 landslideconditioning factors and establish a landslide inventory *** the weights of classes (or factors) is very important toprepare data for machine learning methods to generate LSMs. Wefrst use frequency ratio (FR) and analytic hierarchy process (AHP)techniques to generate the weights. Then, random forest (RF), supportvector machine (SVM), logistic regression (LR), and AHP methods arecombined with FR and AHP weights to yield accurate and reliableLSMs. Finally, the performance of these methods is evaluated by fivestatistical metrics, ROC and R-index. The empirical results have shownthat RF is the best method in terms of R-index and the five metrics, *** rate (0.9661), FP rate (0.0), ACC (0.9835), MAE (0.0046), and RMSE(0.0350) for this study area. This study opens the perspective of weightbasedmachine learning methods for landslide susceptibility mapping.

关键词： Landslide logistic regression random forest SvM Vietnam

Ni Single Atoms and Ni Phosphate Clusters Synergistically Triggered Surface-Functionalized MoS_(2)Nanosheets for High-performance Freshwater and Seawater Electrolysis

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Energy & Environmental Materials 2022年第4期5卷 1340-1349页

作者： Min Sung Kim Duy thanh Tran thanh hai Nguyen Van An Dinh Nam Hoon Kim Joong Hee lee Department of Nano Convergence Engineering Jeonbuk National UniversityJeonju 54896Republic of Korea Department of Precision Engineering Graduate School of EngineeringOsaka University2-1Yamada-okaSuita 565-0871Japan Carbon Composite Research Center Department of Polymer-Nanoscience and TechnologyJeonbuk National UniversityJeonju 54896Republic of Korea

Two-dimensional metal dichalcogenides have been evidenced as potential electrocatalysts for hydrogen evolution reaction(HER);however,their application is limited by a poor oxygen evolution reaction(OER)activity due to insufficient number/types of multi-integrated active *** this study,we report a novel bifunctional catalyst developed by simultaneous engineering of single nickel atoms(Ni_(SA)) and nickel phosphate clusters(Ni_(Pi)) to synergistically trigger surface-functionalized MoS_(2) nanosheets(NSs)resulting in high reactivities for both HER and *** Ni_(SA)-Ni_(Pi)/MoS_(2)NSs material exhibits a fairly Pt-like HER behavior with an overpotential of 94.0 mV and a small OER overpotential of 314.0 mV to reach 10 mA cm^(-2) in freshwater containing 1.0 M *** results of the catalyst are well supported by theoretical study,which reveals the significant modulation of electronic structure and enrichment of electroactive site number/types with their reasonably adjusted free adsorption *** evaluating practicability,the Ni_(SA)-Ni_(Pi)/MoS_(2)NSs-based electrolyzer delivers effective operation voltage of 1.62,1.52,and 1.66 V at 10 mA cm^(-2) and superior long-term stability as compared to Pt/C//RuO_(2) system in freshwater,mimic seawater,and natural seawater,*** present study indicates that the catalyst is a promising candidate for the practical production of green hydrogen via water electrolysis.

关键词： bifunctional electrocatalyst freshwater and seawater electrolysis nickel phosphate clusters nickel single atoms surface-functionalized-MoS_(2)nanosheets

Numerical investigation of the influence of casting techniques on fiber orientation distribution in ECC

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Frontiers of Structural and Civil Engineering 2022年第11期16卷 1424-1435页

作者： Chung Nguyen VAN hai TRAN thanh Thuc Nhu NGUYEN Jianchun LI Faculty of Civil Engineering Ho Chi Minh City University of Technology and EducationHo Chi Minh 721400Vietnam School of Civil and Environmental Engineering University of Technology SydneySydneyNSW 2007Australia School of Civil Engineering Hue Industrial CollegeHue 49120Vietnam

Engineered cementitious composites(ECC),also known as bendable concrete,were developed based on engineering the interactions between fibers and cementitious *** orientation of fibers,in this regard,is one of the major factors influencing the ductile behavior of this *** this study,fiber orientation distributions in ECC beams influenced by different casting techniques are evaluated via numerical modeling of the casting *** casting directions and two casting positions of the funnel outlet with beam specimens are modeled using a particle-based smoothed particle hydrodynamics(SPH)*** this SPH approach,fresh mortar and fiber are discretized by separated mortar and fiber particles,which smoothly interact in the computational domain of *** movement of fiber particles is monitored during the casting ***,the fiber orientations at different sections of specimens are determined after the fresh ECC stops flowing in the *** simulation results show a significant impact of the casting direction on fiber orientation distributions along the longitudinal wall of beams,which eventually influence the flexural strength of *** addition,casting positions show negligible influences on the orientation distribution of fibers in the short ECC beam,except under the pouring position.

关键词： ECC fiber orientation distribution casting direction casting position

Eye Strain Detection During Online learning

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Intelligent Automation & Soft Computing 2023年第3期35卷 3517-3530页

作者： le Quang Thao Duong Duc Cuong Vu Manh Hung le thanh Vinh Doan Trong Nghia Dinh Ha hai Nguyen Nhan Nhi Faculty of Physics VNU University of ScienceHanoi100000Vietnam University of Science Vietnam National UniversityHanoi100000Vietnam VNU-HUS High School for Gifted StudentsHanoi100000Vietnam Hanoi-Amsterdam High School for the Gifted Hanoi100000Vietnam

The recent outbreak of the coronavirus disease of 2019(Covid-19)has been causing many disruptions among the education systems worldwide,most of them due to the abrupt transition to online *** sudden upsurge in digital electronic devices usage,namely personal computers,laptops,tablets and smart-phones is unprecedented,which leads to a new wave of both mental and physical health problems among students,for example eye-related *** overexpo-sure to electronic devices,extended screen time usage and lack of outdoor sun-light have put a consequential strain on the student’s ophthalmic health because of their young age and a relative lack of responsibility on their own *** to take appropriate external measures to mitigate the negative effects of this pro-cess could lead to common ophthalmic illnesses such as myopia or more serious *** remedy this situation,we propose a software solution that is able to track and capture images of its users’eyes to detect symptoms of eye illnesses while simultaneously giving them warnings and even offering *** meet the requirements of a small and light model that is operable on low-end devices without information loss,we optimized the original MobileNetV2 model with depth-wise separable convolutions by altering the parameters in the last layers with an aim to minimize the resizing of the input image and obtained a new model which we call *** with applying the knowledge distillation tech-nique and ResNet-18 as a teacher model to train the student model,we have suc-cessfully increased the accuracy of the EyeNet model up to 87.16%and support the development of a model compatible with embedded systems with limited computing power,accessible to all students.

关键词： Digital eye strain Covid-19 online study knowledge distillation eye care EyeNet