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Double-loop Control Structure Using Proportional Resonant and Sequence-decoupled Resonant Controllers in Static Coordinates for Dynamic Voltage Restorer

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Chinese Journal of Electrical Engineering 2019年第3期5卷 10-19页

作者： Vu Thai Hung Hongchun Shu Le ngoc Giang nguyen Duc The School of Electric Power Engineering Kunming University of Science and TechnologyKunming 650500China AD-AF Academy of Viet Nam Son TayHa Noi 100000Viet Nam

Among incidents on grids,the sag/swell voltage is considered as the most frequent *** solve this problem,custom power devices are *** particular,the dynamic voltage restorer(DVR)is a modern and efficient customer *** are used to mitigate voltage sag/swells and harmonics on the load bus,thus protecting the sensitive *** DVR is a serial compensator that applies a voltage to the point of common coupling to maintain the voltage of sensitive load at the nominal *** improve the performance of DVRs,in this study,the control strategy of the two-stage loop circuit is *** external voltage control loop uses a sequence-decoupled resonant(SDR)controller,and the inner current-control loop uses the proportional resonant(PR)controller implemented in the stationary frameαβ.

关键词： Dynamic voltage restorer PR controller SDR controller nonlinear load

An Ontology-Based Question Answering System for University Admissions Advising

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Intelligent Automation & Soft Computing 2023年第4期36卷 601-616页

作者： Thi Thanh Sang nguyen Dang Huu Trong Ho ngoc Tram Anh nguyen School of Computer Science and Engineering International UniversityVNU-HCMCVietnam National UniversityHo Chi Minh CityVietnam

Question-Answer systems are now very popular and crucial to support human in automatically responding frequent questions in manyﬁ***,these systems depend on learning methods and training ***,it is necessary to prepare such a good dataset,but it is not an easy *** ontol-ogy-based domain knowledge base is able to help to reason semantic information and make effective answers given user *** study proposes a novel chatbot model involving ontology to generate efﬁcient responses automatically.A case study of admissions advising at the International University–VNU HCMC is taken into account in the proposed chatbot.A domain ontology is designed and built based on the domain knowledge of university admissions using Protégé.The Web user interface of the proposed chatbot system is developed as a prototype using *** includes a search engine reasoning the ontology and generat-ing answers to users’*** experiments are carried out to test how the system reacts to different ***ﬁrst experiment examines questions made from some templates,and the second one examines normal questions taken from frequent *** results have shown that the ontology-based chatbot can release meaningful and long *** results are analysed to prove the proposed chatbot is usable and promising.

关键词： Ontology chatbots answer-question systems domain knowledge base admissions advising

Electrochemical Immunosensor for Detection of Atrazine Based on Polyaniline/Graphene

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Journal of Materials Science & Technology 2016年第6期32卷 539-544页

作者： nguyen Van Chu nguyen Hai Binh Cao Thi Thanh nguyen Van Tu nguyen Le Huy nguyen Tuan Dzung Phan ngoc Minh Vu Thi Thu Tran Dai Lam Institute of Materials Science Vietnam Academy of Science and Technology18 Hoang Quoc VietCau Giay.HanoiViet Nam School of Chemical Engineering.Hanoi University of Science and Technology 1 Dai Co VietHanoiViet Ham Institute for Tropical Technology.Vietnam Academy of Science and Technology 18 Hoang Quoc VietHanoiViet Nam Center for High Technology Development Vietnam Academy of Science and Technology18 Hoang Quoc VietHanoiViet Nam University of Science and Technology of Hanoi.18 Hoang Quoc Viet HanoiViet Ham Graduate University of Science and Technology.Vietnam Academy of Science and Technology 18 Hoang Quoc Viet.HanoiViet Nam

In this study, a novel layer-by-layer polyaniline/graphene （PANi/Gr） structure for electrochemical detec- tion of atrazine was developed. Gr film was synthesized by thermal chemical vapor deposition （CVD） method and transferred onto the PANi-predeposited microelectrode. The properties of PANi/Gr film were thoroughly investigated by high-resolution transmission electron microscopy and Raman techniques. The most attractive feature of this system is a suitable microenvironment, which could provide an amplifi- cation of the conductive signal, thus may contribute to enhancing electron transfer and subsequently improve the sensitivity in electrochemical measurements. With low detection limit （- 43 × 10 -12 g/L）, ac-ceptable stability and good reproducibility, the proposed electrochemical immunosensor could be advantageously extended for multiplexed detection of other agents of environmental pollution.

关键词： Electrochemical immunosensor Polyaniline Graphene Atrazine

Novel Criteria for Exponential Stability of Linear Non-Autonomous Functional Differential Equations

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Journal of Systems Science & Complexity 2019年第2期32卷 479-495页

作者： PHAM HUU ANH ngoc THAI BAO Tran CAO THANH Tinh nguyen DINH Huy Department of Mathematics Vietnam National University-HCMC International University Faculty of Information Systems Vietnam National University-HCMC University of Information Technology Department of Mathematics Vietnam National University-HCMC University of Information Technology Division of Applied Mathematics Faculty of Applied Sciences Vietnam National University-HCMC Ho Chi Minh city University of Technology

General linear non-autonomous functional differential equations are considered. Explicit criteria for exponential stability are given. Furthermore, the authors present an explicit robust stability bound for systems su... 详细信息

关键词： Exponential stability linear functional differential equations perturbation

Fabrication and Characterization of Multi-layer Heat Mirror with Photocatalytic Properties

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Chinese Physics Letters 2009年第11期26卷 152-155页

作者： Tran Le Tuan Tran Huu Chi nguyen Dac ngoc Son Luu Minh Nam Hoang Dinh Quan nguyen Department of Applied Physics College of Natural Science National University of He Chi Mirth City 227 Nguyen Van Cu District 5 Ward 4 He Chi Minh City Vietnam Department of Chemical Engineering College of Technology National University of He Chi Minh City 168 Ly Thuong Kiet District 10 Ho chi Minh City Vietnam

A novel TiO2（5）/TiO2（buffer）/Ti（4）/Ag（3）/Ti（2）/TiO2（1） multi-layer film coating with corning glass is designed and fabricated by a dc magnetron sputtering method as a renovation of the well-known TiO2/Ti/Ag/Ti/TiO2 system in order to obtain a heat mirror system with photocatalytic properties due to sufficient thickness of the Ti02 layer. The outer TiO2 layer is fabricated in two steps, possibly claimed as two layers TiO2（5） and TiO2（buuer）, among which TiO2（buffer） the 70-nm-thick layer deposited in poor oxygen effectively minimizes the oxidation toward its neighbor Ti（4） layer. The optimal total thickness of the TiO2（5） and TiO（buffer） di-layer is found to be 300nm to yield a highly photo-catalytic property of the film without affecting the optical properties considerably. This multi-layer film can transmit light of above 75-85% in the visible spectrum （380 ≤ λ≤ 760 nm） and reflect radiation of above 90% in the infrared spectrum （ λ≥760 nm）. Such multi-layer coatings are strongly recommended not only as promising transparent heat mirrors but also as photo-catalytic films for architectural window coatings.

关键词： Condensed matter: electrical magnetic and optical Surfaces interfaces and thin films Chemical physics and physical chemistry

EXISTENCE AND STABILITY OF PERIODIC AND ALMOST PERIODIC SOLUTIONS TO THE BOUSSINESQ SYSTEM IN UNBOUNDED DOMAINS

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Acta Mathematica Scientia 2022年第5期42卷 1875-1901页

作者： Thieu Huy nguyen Truong Xuan PHAM Thi ngoc Ha VU The Sac LE School of Applied Mathematics and Informatics Hanoi University of Science and Technology Vien Toan ung dung va Tin hocDai hoc Bach khoa Hanoi 1DaiCoVietHanoiVietnam Department of Mathematics Faculty of Information TechnologyThuyloi university Khoa Cong nghe Thong tinBo mon ToanDai hoc Thuy loi175 Tay SonDong DaHa NoiViet Nam Thuyloi University Dai hoc Thuy Loi175 Tay SonDong DaHanoiViet Nam

In this paper we investigate the existence and stability of periodic solutions(on a half-line R_(+))and almost periodic solutions on the whole line time-axis R to the Boussinesq system on several classes of unbounded domains of R^(n) in the framework of interpolation *** the linear Boussinesq system we combine the L^(p)—L^(q)-smoothing estimates and interpolation functors to prove the existence of bounded mild ***,we prove the existence of periodic solutions by invoking Massera’s *** also prove the existence of almost periodic *** we use the results of the linear Boussinesq system to establish the existence,uniqueness and stability of the small periodic and almost periodic solutions to the Boussinesq system using fixed point arguments and interpolation *** results cover and extend the previous ones obtained in[13,34,38].

关键词： Boussinesq systems periodic solutions almost periodic solutions unbounded domains smoothing estimates dual estimates interpolation spaces stability

Cr/nanodiamond composite plating with cobalt cation additive

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中国有色金属学会会刊：英文版 2009年第4期19卷 975-978页

作者： Viet-Hue nguyen Thi-Nam HOANG ngoc-Phong nguyen Sik-Chol KWON Man KIM Joo-Yul LEE Institute of Materials Science Korea Institute of Materials Science

The effect of cationic additive on Cr/nanodiamond plating was *** plating was performed in Sargent *** of deposit was observed by scanning electron microscope(SEM);microhardness by hardness tester;wear rate by tribometer;amount of diamond in deposit by combustion method and passivity by potentiodynamic *** results show that in the presence of cobalt cation,the amount of nanodiamond particle in the deposit is *** increasing diamond particle amount,the metallurgical,mechanical and electrochemical properties of Cr/nanodiamond deposit are ***,this improvement seems to be *** the presence of 10 g/L of nanodiamond powder and 2.5 g/L of cobalt cation in the bath,the amount of diamond particle in deposit is increased by 4 times;and wear rate of Cr-Co/nanodiamond deposit is decreased by 2-3 times as compared with pure Cr/*** passive current of Cr-Co/nanodiamond composite deposit is decreased from 18 to 8 μ*** morphology of Cr/nanodiamond is smooth remarkably in the presence of cobalt cation.

关键词：纳米金刚石粉复合镀层钴离子镀铬添加剂金刚石颗粒扫描电子显微镜形态观察

Gravitationally lensed extended sources: the case of QSO RXJ0911

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Research in Astronomy and Astrophysics 2013年第7期13卷 803-814页

作者： Do Thi Hoai Pham Tuyet Nhung Pham Tuan Anh Frederic Boone Pierre Darriulat Pham ngoc Diep Pham ngoc Dong nguyen Van Hiep nguyen Thi Thao VATLY INST179Hoang Quoc VietCau GiayHanoiVietnam IRAP 14avenue Edouard BelinF31400 ToulouseFrance

After a brief reminder of the mechanism of gravitational lensing of ex- tended sources, the particular case of the host galaxy of QSO RXJ0911, a high red-shift （z - 2.8） quadruply imaged quasar, is explored. The non linearity of the problem, together with the proximity of the source to a cusp of the lens inner caustic, has impor-tant consequences on the dependence of the image appearance on the size and shape of the source. Their expected main features and their interpretation in terms of source extension and shape are investigated in a spirit of simplicity and in preparation for the analysis of high sensitivity and spatial resolution images that will soon be within reach with the completion of the Atacama Large Millimeter/submillimeter Array （ALMA）. In particular, the information on source size carded by relative image brightness is dis-cussed. Extension of the results to other types of quadruply imaged quasars is briefly considered.

关键词： gravitational lensing - galaxies: high-redshift

WiMAX Network Frequency Planning

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WiMAX Network Frequency Planning

作者： nguyen Trong hieu（阮仲孝）昆明理工大学

学位级别：硕士

The IEEE 802.16 standard, commonly known as WiMAX, is the latest technology that has promised to offer broadband wireless access over long distance. Since 2001 WiMAX has evolved from 802.16 to 802.16d for fixed wireless access, and to the new IEEE 802.16e standard with mobility support. In this paper, we provide an overview of the state-of-the-art mobile WiMAX technology and its development. Next, we focus our discussion on deployment scenarios and performance analysis of mobile WiMAX in Vietnam, a developing country with fast growth in Telecommunications.In practice, mobile WiMAX network planning (IEEE Std 802.16e) is described by using GENEX U-net. The system level simulations scenarios (channel models, frequency reuse planning, system loading, etc) will be introduced. Evaluated performance of mobile WiMAX system through fully planning by various parameters of multi-cellular deployment will be presented and discussed.

关键词： bandwidth networking 硕士学位论文昆明理工大学 downlink broadband Figure reuse traffic coverage