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Determining osmotic suction through electrical conductivity for unsaturated low-plasticity soils

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Journal of Rock Mechanics and Geotechnical Engineering 2022年第6期14卷 1946-1955页

作者： Zi Ying Nadia Benahmed Yu-Jun Cui Myriam duc Ecole des Ponts ParisTech Laboratoire Navier/CERMES6-8 Av.Blaise PascalCitéDescartesChamps-sur-MarneMarne-la-ValléeCedex277455France INRAE Aix Marseille UniversityUnitéde Recherche RECOVER3275 Route CézanneAix-en-Provence13182France UniversitéGustave Eiffel IFSTTAR/GERS/SRO14-20 Boulevard NewtonChamps-sur-MarneMarne-la-Vallée77447France

Determining osmotic suction from the electrical conductivity(EC)of soil pore water was widely reported in the ***,while dealing with unsaturated soils,they do not have enough soil pore water to be extracted for a reliable measurement of *** this paper,the chilled-mirror dew-point hygrometer and contact filter paper method were used to determine the total and matric suctions for low-plasticity soils with different salinities(0.05‰,2.1‰,and 6.76‰).A new piecewise function was proposed to calculate the osmotic suction,with the piecewise point corresponding to the first occurrence of precipitated salt in mixed salt solutions(synthetic seawater).EC,ion and salt concentrations used for osmotic suction calculation were transformed from the established relationships of mixed salt solution instead of experimental *** calculated osmotic suction by the proposed equation and the equations in the literature was compared with the indirectly measured one(the difference between the measured total and matric suctions).Results showed that the calculated osmotic suction,especially the one calculated using the proposed function,was in fair agreement with the indirectly measured data(especially for specimens with higher salinity of 6.76‰),suggesting that the transformation of EC and concentrations from the established relationship is a good alternative to direct measurement for lowplasticity *** particular,the proposed method could be applied to unsaturated low-plasticity soils which do not have enough soil pore water for a proper EC measurement.

关键词： Unsaturated soils Mixed salt solutions Osmotic suction Electrical conductivity(EC)

Global Robust and Adaptive Output Feedback Dynamic Positioning of Surface Ships

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Journal of Marine Science and Application 2011年第3期10卷 325-332页

作者： Khac duc Do School of Mechanical and Aerospace Engineering Nanyang Technological University

A constructive method was presented to design a global robust and adaptive output feedback controller for dynamic positioning of surface ships under environmental disturbances induced by waves, wind, and ocean currents. The ship's parameters were not required to be known. An adaptive observer was first designed to estimate the ship's velocities and parameters. The ship position measurements were also passed through the adaptive observer to reduce high frequency measurement noise from entering the control system. Using these estimate signals, the control was then designed based on Lyapunov's direct method to force the ship's position and orientation to globally asymptotically converge to desired values. Simulation results illustrate the effectiveness of the proposed control system. In conclusion, the paper presented a new method to design an effective control system for dynamic positioning of surface ships.

关键词： dynamic positioning surface vessel robust and adaptive output feedback nonlinear control

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越南学习者汉语愉悦与人格特质的关系研究

红河学院学报 2024年第4期22卷 27-30页

作者：陈德忠朱氏莺中央民族大学国际教育学院北京100081 华东师范大学国际汉语文化学院上海200062

近年来,学习者的积极情绪成为了二语习得领域的研究热点。文章通过对107名越南学习者的汉语愉悦和人格特质的考察,探究汉语愉悦与人格特质的关系。结果显示:(1)学习者的总体汉语愉悦水平很高,个人汉语愉悦和汉语教师愉悦是主要的愉悦来... 详细信息

近年来,学习者的积极情绪成为了二语习得领域的研究热点。文章通过对107名越南学习者的汉语愉悦和人格特质的考察,探究汉语愉悦与人格特质的关系。结果显示:(1)学习者的总体汉语愉悦水平很高,个人汉语愉悦和汉语教师愉悦是主要的愉悦来源,汉语环境愉悦水平有待提高;(2)学习者的人格特质分布均衡,都具有开放性、尽责性、外向性、亲和性及神经质等五类人格特质;(3)除了神经质人格,其他四类人格特质都与汉语愉悦呈正相关,汉语愉悦水平的提高有助于人格特质的积极发展。文章基于研究结果分析了适合不同人格特质的汉语愉悦提升方式,可为个性化汉语二语教育提供一定的启示。

关键词：越南学习者汉语愉悦人格特质

Digital Earth:A platform for the SDGs and green transformation at the global and local level,employing essential SDGs variables

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Big Earth Data 2021年第4期5卷 476-496页

作者： Hiromichi Fukui duc Chuc Man Anh Phan Chubu Institute for Advanced Studies and International Digital Earth Applied Science Research Center(IDEAS) Chubu UniversityKasugaiJapan Graduate School of Engineering Chubu UniversityKasugaiJapan

The 17 Sustainable Development Goals present clear directions toward the green transformation being sought by the global *** SDGs are an integrated framework,with a complex network of interlinkages between the goals,targets and indicators,and they pose wicked problems to ***,measur-ing progress and achievements with the SDGs requires the integra-tion of various spatio-temporal datasets from different domains and the synthesis of disciplines to describe a system of *** Group on Earth Observations has developed the concept of Essential Variables to describe systems across Societal Benefit Areas that are applicable for this *** Earth is a virtual representation of the planet,potentially encompassing all its sys-tems and life forms,including human *** as a multidimensional,multi-scale,multi-temporal,and multi-layer informa-tion facility,Digital Earth is a valuable platform that can contribute to the achievement of the SDGs and a green *** that end,a set of Essential SDGs Variables(ESDGVs)for the platform are proposed and cases of implementation and use are introduced.

关键词： Digital Earth SDGs Earth Observation interoperability Essential Variables

Rapid design of top-performing metal-organic frameworks with qualitative representations of building blocks

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npj Computational Materials 2023年第1期9卷 585-598页

作者： Yigitcan Comlek Thang duc Pham Randall Q.Snurr Wei Chen Department of Mechanical Engineering Northwestern UniversityEvanstonILUSA Department of Chemical and Biological Engineering Northwestern UniversityEvanstonILUSA

Data-driven materials design often encounters challenges where systems possess qualitative(categorical)***,representing Metal-organic frameworks(MOFs)through different building blocks poses a challenge for designers to incorporate qualitative information into design optimization,and leads to a combinatorial challenge,with large number of MOFs that could be *** this work,we integrated Latent Variable Gaussian Process(LVGP)and Multi-Objective Batch-Bayesian Optimization(MOBBO)to identify top-performing MOFs adaptively,autonomously,and *** showcased that our method(i)requires no specific physical descriptors and only uses building blocks that construct the MOFs for global optimization through qualitative representations,(ii)is application and property independent,and(iii)provides an interpretable model of building blocks with physical *** searching only~1%of the design space,LVGP-MOBBO identified all MOFs on the Pareto front and 97%of the 50 top-performing designs for the CO_(2) working capacity and CO_(2)/N2 selectivity properties.

关键词： properties qualitative autonomous

A New Strategy for the Synthesis of Monomethylhydrazine Using the Raschig Process

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Advances in Chemical Engineering and Science 2021年第3期11卷 228-238页

作者： duc minh Le Anne-Julie Bougrine Olivier duclos Véronique Pasquet Henri Delalu Laboratoire Hydrazines et Composés Energétiques Polyazotés Université Claude Bernard Lyon 1 Villeurbanne France UCBL/CNRS/CNES/ArianeGroup Batiment Raulin Villeurbanne France

A new strategy for the development of monomethylhydrazine (MMH) using the Raschig process is discussed in this publication. The determination of optimal conditions for the synthesis of MMH required the development of a kinetic model. In order to validate the results of the calculation, a device for synthesis under pressure (13 bar) by direct injection of the stoichiometric monochloramine, synthesized using microreactor technology, into monomethylamine (MMA) was developed. The experimental data, in accordance with the theoretical results of the kinetic model, make it possible to establish a new process for the synthesis of monomethylhydrazine.

关键词： Synthesis Raschig Monomethylhydrazine Kinetic Model

Replacement of alkali silicate solution with silica fume in metakaolin-based geopolymers

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International Journal of Minerals,Metallurgy and Materials 2019年第5期26卷 555-564页

作者： Ahmed Nmiri Myriam duc Noureddine Hamdi Oumaya Yazoghli-Marzouk Ezzeddine Srasra National Center for Research in Materials Sciences Technop?le Borj Cedria (CNRSM) Department of Chemistry Faculty of Sciences of Tunis University of Tunis El-Manar French Institute of Science and Technology for Transport Development and Networks (IFSTTAR) Center for Studies and Expertise on Risks Environment Mobility and Development (CEREMA)

A metakaolin(Mk)-based geopolymer cement from Tunisian Mk mixed with different amounts of silica fume(SiO_2/Al_2O_3 molar ratio varying between 3.61 and 4.09) and sodium hydroxide(10M) and without any alkali silicate solution, is developed in this work. After the samples were cured at room temperature under air for 28 d, they were analyzed by X-ray diffraction(XRD), Fourier transform infrared(FTIR) spectroscopy, environmental scanning electron microscopy, mercury intrusion porosimetry, ^(27)Al and ^(29)Si nuclear magnetic resonance(NMR) spectroscopy, and compression testing to establish the relationship between microstructure and compressive strength. The XRD, FTIR, and ^(27)Al and ^(29)Si NMR analyses showed that the use of silica fume instead of alkali silicate solutions was feasible for manufacturing geopolymer cement. The Mk-based geopolymer with a silica fume content of 6 wt%(compared with those with 2% and 10%), corresponding to an SiO_2/Al_2O_3 molar ratio of 3.84, resulted in the highest compressive strength, which was explained on the basis of its high compactness with the smallest porosity. Silica fume improved the compressive strength by filling interstitial voids of the microstructure because of its fine particle size. In addition, an increase in the SiO_2/Al_2O_3 molar ratio, which is controlled by the addition of silica fume, to 4.09 led to a geopolymer with low compressive strength, accompanied by microstructures with high porosity. This high porosity, which is responsible for weaknesses in the specimen, is related to the amount of unreacted silica fume.

关键词： metakaolin silica fume geopolymer cement compressive strength

Identifying high-risk individuals for gastric cancer surveillance from western and eastern perspectives: Lessons to learn and possibility to develop an integrated approach for daily practice

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World Journal of Gastroenterology 2019年第27期25卷 3546-3562页

作者： duc Trong Quach Toru Hiyama Takuji Gotoda Department of Internal Medicine University of Medicine and Pharmacy at Hochiminh CityHo Chi Minh 70000Vietnam Health Service Center Hiroshima UniversityHigashihiroshima 739-8514Japan Division of Gastroenterology and Hepatology Department of MedicineNihon University School of MedicineTokyo 101-8309Japan

Current evidence shows that individuals with gastric dysplasia, severe and extensive gastric atrophy, extensive gastric intestinal metaplasia and the incomplete subtype of intestinal metaplasia are at high risk for gastric cancer(GC) development. There are several approaches to identifying these subjects,including noninvasive methods, esophagogastroduodenoscopy and *** main approach in Western countries is histology-based while that in Eastern countries with a high prevalence of GC is endoscopy-based. Regarding asymptomatic individuals, the key issues in selecting applicable approaches are the ability to reduce GC mortality and the cost-effectiveness of the approach. At present, population-based screening programs have only been applied in a few Asian countries with a high risk of GC. Pre-endoscopic risk assessment based on demographic and clinical features, such as ethnicity, age, gender, smoking and Helicobacter pylori status, is helpful for identifying subjects with high pre-test probability for a possibly cost-effective approach, especially in intermediate-and low-risk countries. Regarding symptomatic patients with indications for esophagogastroduodenoscopy, the importance of opportunistic screening should be emphasized. The combination of endoscopic and histological approaches should always be considered as endoscopy provides a real-time assessment of the patient’s risk level. In addition, imaging enhanced endoscopy(IEE) has been shown to facilitate targeted biopsies resulting in better correlation between endoscopic and histological findings. Currently, the use of IEE is recommended for endoscopic examinations, and the Operative Link for Gastric Intestinal Metaplasia or Operative Link on Gastritis Assessment grading systems are recommended for histological examinations whenever available. However,resource limitations are an important barrier in many regions worldwide. Thus,for an approach to be applicable in real-life practice, it should be not only

关键词： Gastric cancer Precancerous gastric lesions Dysplasia Gastric atrophy Chronic atrophic gastritis Intestinal metaplasia Surveillance Screening Costeffective

Performance evaluation of a two-way relay network with energy harvesting^and hardware noises

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Digital Communications and Networks 2021年第1期7卷 45-54页

作者： Nguyen Tien Tung Pham minh Nam Phu Tran Tin Faculty of Electronics Technology Industrial University of Ho Chi Minh CityHo Chi Minh CityVietnam Wireless Communcations Research Group Faculy of Electrical and Electronics EngineeringTon Duc Thang UniversityHo Chi Minh CityVietnam

In this paper,we propose a Two-Way Cognitive Relay Network(TWCRN)where the secondary users operate on an underlay mode to access the licensed *** the proposed protocols,two secondary sources transmit their data to a relay in the first time slot,and then the relay would forward the received information to both sources in the remaining ***,the relay is self-powered by harvesting energy from ambient Radio Frequency(RF)signals,using the Time Switching(TS)and the Power Switching(PS)*** paper concentrates on eval-uating the performance of the secondary networks under the impact of hardware impairments and co-channel interference from the primary *** particular,based on the secondary transmitters'constraint power,we derive the closed-form expressions of the outage probability and the throughput over Rayleigh fading channels in two cases:TS and *** also investigate the energy efficiency issue and the locally optimal position of the relay to maximize the system throughput,which provides much information to install the relay ***,our derivations are verified by Monte Carlo simulation.

关键词： Energy harvesting Two-way relay Energy efficiency Hardware impairments Cognitive network