检索结果-南通市图书馆

Two-dimensional perovskite SrNbO_(2) N with Zr doping for accelerating photoelectrochemical water splitting

在线全文

学校读者我要写书评

暂无评论

Journal of Materials Science & Technology 2023年第11期142卷 176-184页

作者： Thanh Tam Thi tran van-huy Trinh Jeongsuk Seo Department of Chemistry College of Natural SciencesChonnam National University77 Yongbong-roBuk-guGwangju 61186South Korea

The superior ability of perovskite-type SrNbO_(2) N to absorb intensive visible light makes it a potential semiconductor to produce hydrogen and oxygen by photoelectrochemical(PEC)water splitting under *** surface morphologies,such as shape and structure,of the oxynitride strongly affect its photoactivity,although the mechanism has been hardly ***,we report a two-dimensional(2D)porous SrNbO_(2) N plate with Zr doping,nitrided from layered perovskite Sr_(5)Nb_(4)O_(15) and also its largely enhanced PEC water splitting ***^(4+)was doped in Sr_(5)Nb_(4)O_(15) during flux-assisted calcination using KCl,producing 2D-type truncated-octahedral Sr_(5)Nb_(4)O_(15):Zr plates approximately 50 nm in *** nitridation completely transformed Sr_(5)Nb_(4)O_(15):Zr to 2D single-crystalline SrNbO_(2) N:Zr with a large surface area,which was subsequently used to fabricate a thin and uniform photoanode by the spin coating *** a result,the Co(OH)_(x)/SrNbO_(2) N:Zr/FTO photoanode capable of absorbing visible light of up to 680 nm exhibited an activity of 2.0 mA cm^(-2) at 1.23 V vs the reversible hydrogen electrode for water splitting under AM 1.5G simulated *** improvement in photoactivity mainly originated from the 2D surface morphology of SrNbO_(2) N:Zr,which is clearly distinguishable from 3D-type *** to electrochemical analyses,the 2D structure of SrNbO_(2) N:Zr boosted the separation and accelerated the transfer of charges photogenerated during the water splitting,thus driving the reaction ***,the result empirically demonstrates that controlling the surface morphology of SrNbO_(2) N is an effective strategy to suppress the recombination of charges and minimize their diffusion pathway,eventually enhancing the PEC activity.

关键词： Solar water splitting Water oxidation BaNbO_(2)N Doping engineering Flux-assisted calcination Spin coating

An Enhanced Ensemble-Based Long Short-Term Memory Approach for Traffic Volume Prediction

在线全文

维普期刊数据库

学校读者我要写书评

暂无评论

Computers, Materials & Continua 2024年第3期78卷 3585-3602页

作者： Duy Quang tran huy Q.tran Minh van Nguyen Faculty of Civil Engineering Nha Trang UniversityNha Trang650000Vietnam Robotics and Mechatronics Research Group Faculty of Engineering and TechnologyNguyen Tat Thanh UniversityHo Chi Minh City700000Vietnam Department of Civil Engineering Ho Chi Minh City University of Technology and EducationHo Chi Minh City700000Vietnam

With the advancement of artificial intelligence,traffic forecasting is gaining more and more interest in optimizing route planning and enhancing service *** volume is an influential parameter for planning and operating traffic *** study proposed an improved ensemble-based deep learning method to solve traffic volume prediction problems.A set of optimal hyperparameters is also applied for the suggested approach to improve the performance of the learning *** fusion of these methodologies aims to harness ensemble empirical mode decomposition’s capacity to discern complex traffic patterns and long short-term memory’s proficiency in learning temporal ***,a dataset for automatic vehicle identification is obtained and utilized in the preprocessing stage of the ensemble empirical mode decomposition *** second aspect involves predicting traffic volume using the long short-term memory ***,the study employs a trial-and-error approach to select a set of optimal hyperparameters,including the lookback window,the number of neurons in the hidden layers,and the gradient descent ***,the fusion of the obtained results leads to a final traffic volume *** experimental results show that the proposed method outperforms other benchmarks regarding various evaluation measures,including mean absolute error,root mean squared error,mean absolute percentage error,and *** achieved R-squared value reaches an impressive 98%,while the other evaluation indices surpass the *** findings highlight the accuracy of traffic pattern ***,this offers promising prospects for enhancing transportation management systems and urban infrastructure planning.

关键词： Ensemble empirical mode decomposition traffic volume prediction long short-term memory optimal hyperparameters deep learning

Facile synthesis of FeFe2O4 magnetic nanomaterial for removing methylene blue from aqueous solution

在线全文

维普期刊数据库

学校读者我要写书评

暂无评论

Progress in Natural Science:Materials International 2019年第6期29卷 648-654页

作者： van-Phuc Dinh Ngoc Quyen tran Nguyen-Que-tran Le Quang-huy tran Trinh Duy Nguyen Gr EEN), Nguyen Tat Thanh University van Tan Le Future Materials and Devices Laboratory Institute of Fundamental and Applied Sciences Duy Tan University Institute of Applied Materials Science VAST Graduate University of Science and Technology VAST Le Quy Don–LBT Highschool Bien Hoa City Dong Nai province Center of Excellence for Green Energy and Environmental Nanomaterials (CE Industrial University of Ho Chi Minh City

A facile and simple chemical precipitation method was utilized to synthesize FeFe2O4magnetic nanomaterial for removing methylene blue（MB） from aqueous solution. Characterizations of this material were examined by using XRD, SEM, FT-IR, TGA-DTG and BET methods. Factors affecting the uptake of methylene blue, including p H, adsorption time, and MB initial concentration were also studied. The measured data were fitted by using four isotherm models including Langmuir, Freundlich, Sips and Temkin. Results showed that the Sips model offers the best fit to the data. In addition, the monolayer MB adsorption capacity obtained from the Langmuir model was 42.35 mg g-1under the optimal conditions of p H = 10 and adsorption time = 80 min. In particular, the uptake of MB onto FeFe2O4magnetic nanomaterial obtained from the kinetic and mechanism studies of the adsorption was in good agreement with prediction of the pseudo-first-order model, whereas the electrostatic interaction was found to play a primary mechanism.

关键词： FeFe2O4 magnetic nanomaterial Adsorption Methylene blue Adsorption mechanism

Introduction to the China-Vietnam Cooperation Project: A Comparative Study of the Holocene Sedimentary Evolution of the Yangtze and Red River Deltas

在线全文

同方期刊数据库

学校读者我要写书评

暂无评论

Journal of Ocean University of China 2018年第6期17卷 1269-1271页

作者： YIN Ping PHUNG van Phach tran Dinh Lan DO huy Cuong BUI van Vuong DUAN Xiaoyong Key Laboratory of Marine Environmental Geology Ministry of Natural Resources Qingdao Institute of Marine Geology Laboratory for Marine Geology Qingdao National Laboratory for Marine Science and Technology Institute of Marine Geology and Geophysics Vietnam Academy of Science and Technology Institute of Marine Environment and Resources Vietnam Academy of Science and Technology

Both China and Vietnam confront the challenges of natural geohazards and environmental changes in their deltas and coastal zones due to rapid urbanization, economic development, and the impacts of global climate change. China and Vietnam initiated a comparative study of the Holocene sedimentary evolution of the Yangtze River Delta(YRD) and Red River Delta(RRD) for the period 2015–2018 in order to improve the understanding of the two delta evolution histories in the Holocene. Previous investigative data of the two rivers, onshore delta plains, and offshore subaqueous deltas have been explored and reinterpreted. New data gleaned from boreholes, piston cores, shallow seismic and hydrodynamic sources have been collected from the offshore YRD and the East China Sea inner shelf, and surface sediments and short cores have been collected from the RRD near-shore areas. Six focal areas of the joint project have been defined for comparative studies of the two deltas, including morphological development, sequential stratigraphy, coastline shifting, sedimentary characteristics, sedimentary dynamics, and correlation with anthropogenic global climate change. The results of these study areas are presented herein. The joint project also includes cooperative capacity building; exchanges of young scientists have been organized during the project period, and hands-on training in laboratory geochemical analysis, numerical modeling, and seismic data processing and interpretation have been provided by China and its Vietnamese geoscientist partners. Joint field excursions were organized to the upstream of the Yangtze and Red Rivers in Yunan Province, China, all the way downstream along the Vietnamese portion of the Red River. These joint studies have, over the past three years, improved understanding of the evolutionary history of these two major rivers and their mechanisms of source to sink. Joint project results of these two major deltas are not limited to the geosciences; the cooperativ

关键词： Yangtze River Delta Red River Delta Holocene sedimentary environment

Single-Layer Wideband Circularly Polarized Antenna Using Non-Uniform Metasurface for C-band Applications

在线全文

学校读者我要写书评

暂无评论

Computers, Materials & Continua 2021年第8期68卷 2487-2498页

作者： huy Hung tran Khoa Nguyen-Dang Niamat Hussain Faculty of Electrical and Electronic Engineering PHENIKAA UniversityHanoi12116Vietnam PHENIKAA Research and Technology Institute(PRATI) A&A Green Phoenix Group JSCCau Giay11313HanoiVietnam Department of Computer and Communication Engineering Chungbuk National UniversityCheongju 28644Korea

A single-layer design of non-uniform metasurface(MS)based circularly polarized(CP)antenna with wideband operation characteristic is proposed and investigated in this *** antenna is excited by a truncated corner squared patch as a primary radiating CP ***,a non-uniform MS is placed in the same layer with the driven *** increasing the impedance bandwidth,the non-uniform MS also generates two additional CP bands in the high frequency band,leading to significantly increase the antenna’s overall *** use of non-uniform MS distinguishes our design from the other CP MS based antennas in literature,in which the MS is formed by multiple uniform unit cells and placed in different layer with the radiating *** validation,an antenna prototype,whose overall dimensions of 0.94λ_(o)×0.94λ_(o)×0.06λ_(o) at the center operating frequency,is fabricated and experimentally *** measured operating bandwidth with|S11|≤−10 dB and AR≤3 dB is 27.1%(5.1–6.7 GHz)and the broadside gain within this band is from 5.7 to 7.2 *** to the other related works,the proposed antenna has advantage of very wideband operation with single-layer design.

关键词： Circular polarization metasurface non-uniform patch antenna wideband

One-loop contributions for h→ℓℓγ and e−e+→hγ in the U(1)_(B−L) extension of the standard model

在线全文

维普期刊数据库

学校读者我要写书评

暂无评论

Chinese Physics C 2024年第5期48卷 23-49页

作者： tran Dzung Tri Thanh huy Nguyen Khiem Hong Phan Institute of Fundamental and Applied Sciences Duy Tan UniversityHo Chi Minh City 700000Vietnam Faculty of Natural Sciences Duy Tan UniversityDa Nang City 550000Vietnam VNUHCM-University of Science 227 Nguyen Van CuDistrict 5Ho Chi Minh CityVietnam

We present one-loop contributions for h→ℓℓγ with ℓ=νe,μ,τ,e,μ and e−e+→hγ in the U(1)_(B−L) extension of the standard model. In the phenomenological results, the signal strengths for h→ℓℓγ at the Large Hadron Collider and for e−e+→hγ at future lepton colliders are analyzed in the physical parameter space for both the vector and chiral B−L models. We found that the contributions from the neutral gauge boson Z′ to the signal strengths are rather small. Consequently, the effects will be difficult to probe at future colliders. However, the impacts of charged Higgs and CP-odd Higgs in the chiral B−L model on the signal strengths are significant and can be measured with the help of the initial polarization beams at future lepton colliders.

关键词： Higgs phenomenology one-loop Feynman integrals analytic methods for quantum field theory dimensional regularization future lepton colliders

Rare-earth free sensitizer in NaLuCrF_4:Er upconversion material

在线全文

学校读者我要写书评

暂无评论

Journal of Rare Earths 2019年第4期37卷 345-349页

作者： Bui The huy Zayakhuu Gerelkhuu The-Long Phan Ngo tran Yong-IllLee Institute of Research and Development Duy Tan University Department of Chemistry Changwon National University Department of Physics Hankuk University of Foreign Studies

Upconversion phosphors are known as a material system that can convert near-infrared light into visible/ultraviolet emissions by sequentially absorbing multiple photons. The studies on upconversion materials often use two rare earth(RE) ions as a sensitizer-activator pair. We investigated the influences on luminescence intensity depending on Cr-doping content(x) of hexagonal NaLu_(0.98-x)Cr_xF4 Er_(0.02)(x = 0-0.9)upconversion material by substituting Lu^(3+) ions with Cr^(3+)in the absence of Gd^(3+). The change in upconversion luminescence intensity appears with saddle-like shape. We suggest that Cr^(3+) ions play the dual role as a constituent in host lattice and a sensitizer in the upconversion process. Optimal conditions for gaining the strongest upconversion emission correspond to x = 0.3-0.5, where there are effective energy transfers between Cr^(3+) and Er^(3+) ions and Cr-Er dimers. Apart from these values, the emission intensity decreases rapidly which can be ascribed to the absence of multiple-photon absorption for the case of low Cr^(3+) contents, and to the coupling between Cr^(3+) and/or Er^(3+) ions for the case of high Cr^(3+)contents. Magnetization and electron-spin-resonant measurements were performed to understand the correlation between the optical and magnetic properties.

关键词： Upconversion materials Sensitizer transition metal ions Magnetism

Fuzzy Feedback Control for Electro-Hydraulic Actuators

在线全文

学校读者我要写书评

暂无评论

Intelligent Automation & Soft Computing 2023年第5期36卷 2441-2456页

作者： Tan Nguyen van huy Q.tran Vinh Xuan Ha Cheolkeun Ha Phu huynh Minh School of Engineering-Technology Thu Dau Mot UniversityThu Dau Mot City590000Vietnam Faculty of Engineering-Technology Nguyen Tat Thanh UniversityHo Chi Minh City754000Vietnam Hue Industrial College Hue City530000Vietnam Robotics and Mechatronics Lab University of UlsanUlsan City44610Korea

Electro-hydraulic actuators(EHA)have recently played a signiﬁcant role in modern industrial applications,especially in systems requiring extremely high *** can be explained by EHA’s ability to precisely control the position and force through advanced sensors and innovative control *** of the promising approaches to improve control accuracy for EHA systems is applying classical to modern control algorithms,in which the proportional–inte-gral–derivative(PID)algorithm,fuzzy logic controller,and a hybrid of these methods are popular *** this paper,we developed a novel version of the fuzzy control algorithm and linear feedback control method,namely fuzzy lin-ear feedback control,to improve the control *** achieve the highest performance,weﬁrst designed a mathematical EHA model based on the Matlab/Simulink software packages thanks to the selected parameters,which are similar to a real EHA ***,we respectively applied PID,fuzzy PID(FPID),and fuzzy linear feedback control(FLFC)before comparing them to have a full view of the outstanding advantages of the proposed *** simulation results showed that the proposed FLFC algorithm is approximately 99%and 77%super-ior in performance to the PID and feedback control algorithms,respectively.

关键词： Electro-hydraulic actuator fuzzy PID feedback control

Determination of Helmert transformation parameters for continuous GNSS networks:a case study of the Géoazur GNSS network

在线全文

维普期刊数据库

学校读者我要写书评

暂无评论

Geo-Spatial Information Science 2023年第1期26卷 125-138页

作者： Dinh Trong tran Jean-Mathieu Nocquet Ngoc Dung Luong Dinh huy Nguyen Department of Geodesy and Geomatics Engineering Hanoi University of Civil EngineeringHanoiVietnam UniversitéCôte d’Azur CNRSObservatoire de la Côte d’AzurIRDValbonneFrance

In this paper,we propose an approach to determine seven parameters of the Helmert transfor-mation by transforming the coordinates of a continuous GNSS network from the World Geodetic System 1984(WGS84)to the International Terrestrial Reference *** includes(1)convert-ing the coordinates of common points from the global coordinate system to the local coordinate system,(2)identifying and eliminating outliers by the Dikin estimator,and(3)estimating seven parameters of the Helmert transformation by least squares(LS)estimation with the“clean”data(*** removed).Herein,the local coordinate system provides a platform to separate points’horizontal and vertical ***,the Dikin estimator identifies and eliminates outliers in the horizontal or vertical component *** is significant because common points in a continuous GNSS network may contain *** proposed approach is tested with the Géoazur GNSS network with the results showing that the Dikin estimator detects outliers at 6 out of 18 common points,among which three points are found with outliers in the vertical compo-nent ***,instead of eliminating all coordinate components of these six common points,we only eliminate all coordinate components of three common points and only the vertical component of another three common ***,the classical LS estimation is applied to“clean”data to estimate seven parameters of the Helmert transformation with a significant accuracy *** Dikin estimator’s results are compared to those of other robust estimators of Huber and Theil-Sen,which shows that the Dikin estimator performs ***,the weighted total least-squares estimation is implemented to assess the accuracy of the LS estimation with the same *** inter-comparison of the seven estimated parameters and their standard deviations shows a small difference at a few per million levels(E-6).

关键词： Continuous GNSS tectonic geodesy Dikin estimation Helmert transformation