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A Novel Hybrid Data Clustering Algorithm Based on Artificial Bee Colony Algorithm and K-Means

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Chinese Journal of Electronics 2015年第4期24卷 694-701页

作者： tran dang cong WU Zhijian WANG Zelin DENG Changshou State Key Laboratory of Software Engineering School of Computer Wuhan University Vietnam Academy of Science and Technology School of Information Science and Technology Jiujiang University

To improve the performance of K-means clustering algorithm, this paper presents a new hybrid approach of Enhanced artificial bee colony algorithm and Kmeans(EABCK). In EABCK, the original artificial bee colony algorithm(called ABC) is enhanced by a new mutation operation and guided by the global best solution(called EABC). Then, the best solution is updated by Kmeans in each iteration for data clustering. In the experiments, a set of benchmark functions was used to evaluate the performance of EABC with other comparative ABC variants. To evaluate the performance of EABCK on data clustering, eleven benchmark datasets were utilized. The experimental results show that EABC and EABCK outperform other comparative ABC variants and data clustering algorithms, respectively.

关键词： Data clustering K-means Artificial bee colony Mutation operation

Thermal Performance Prediction in the Air Gap of a Rotor-Stator Configuration: Effects of Numerical Models

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Journal of Thermal Science 2020年第1期29卷 206-218页

作者： dang Dinh-Dong PHAM Xuan-Tan NGUYEN Chi-cong Department of Mechanical Engineering École de technologie supérieureMontrealQCCanada Hydro-Québec’s research institute VarennesQCCanada

This study is dedicated to a numerical investigation of convective heat transfer on the rotor surfaces of a rotor-stator configuration that is typically found in large *** computational fluid dynamics calculations with two turbulence modelling approaches are used to predict the flow structure and heat transfer in the air gap of the rotor-stator *** steady state mixing plane approach is employed at the interface to couple the rotor and stator *** show that the location of mixing plane interface in the air gap plays an important role in the prediction of heat transfer on the pole ***,it is indicated that the prediction of temperature distribution on the pole face is greatly affected by the turbulence models ***,through a comparison between the pure convective and conjugate heat transfer methodologies,it is shown that the inclusion of solid domain into the numerical model significantly improves the thermal prediction of the solid components of the machine.

关键词： hydro-generators electrical cooling mixing plane windage loss conjugate heat transfer

Effects of Silicon-Based Fertilizer on Growth, Yield and Nutrient Uptake of Rice in Tropical Zone of Vietnam

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Rice science 2017年第5期24卷 283-290页

作者： tran Xuan CUONG Hayat ULLAH Avishek DATTA tran cong HANH Department of Food Agriculture and Bioresources School of Environment Resources and Development Asian Institute of Technology Pathum Thani 12120 Thailand Department of Soil Science Faculty of Agriculture Forestry and Fishery Hong Duc University Dong Ve Thanh Hoa 440000 Vietnam

Application of silicon(Si) could greatly boost rice yield and mitigate abiotic stress,especially drought.A field experiment was conducted during 2015 at the research farm of Hong Duc University,Thanh Hoa City,Vietnam,to evaluate the effects of five different combined doses of standard fertilizer practice and Si fertilizer on growth,yield and yield components,as well as nutrient uptake of *** treatments consisted of the recommended dose of fertilizer(RDF,110 kg/hm^2 N + 90 kg/hm^2 P_2O_5 + 80 kg/hm^2 K_2O) as the control,RDF + 100 kg/hm^2 SiO_2,RDF + 200 kg/hm^2 SiO_2,RDF + 300 kg/hm^2 SiO_2 and RDF + 400 kg/hm^2 SiO_*** results showed that the growth,grain and straw yields as well as yield components(number of grains per panicle,seed-setting rate and 1000-grain weight) were significantly affected by Si *** highest grain yield of 3 705 kg/hm^2 was obtained with the highest level of Si fertilizer in combination with RDF(RDF + 400 kg/hm^2 SiO_2),however,it was statistically at par with the yields obtained with RDF + 300 kg/hm^2 SiO_2(3 664 kg/hm^2) and RDF + 200 kg/hm^2 SiO_2(3 621 kg/hm^2).The optimum dose of Si fertilizer with maximized grain yield(3 716 kg/hm^2) was 329 kg/hm^2 SiO_*** nutrient(Si,N,P and K) uptakes of rice were also significantly enhanced by Si *** application at the level of 329 kg/hm^2 along with RDF would help in the sustainable production of rice in the tropical zone of Vietnam.

关键词： silicon yield nutrient uptake standard fertilizer practice rice fertilizer

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

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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

Geology,Fluid Inclusion and Isotopic Study of the Neoproterozoic Suoi Thau Copper Deposit,Northwest Vietnam

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Acta Geologica Sinica(English Edition) 2016年第3期90卷 913-927页

作者： tran Mydung LIU Junlai LI Xiaochun dang Mycung General Department of Geology and Minerals of Viet Nam HanoiVietnam State Key Laboratory of Geological Processes and Mineral Resources China University of GeoseieneesBeijing 10083China Department of Earth Sciences The University of Hong KongChina Department of Science and Technology Ministry of Natural Resources and Environment of the Socialist Republic of VietnamHanoiVietnam

The Sin Quyen-Lung Po district is an important Cu metallogenic province in Vietnam, but there are few temporal and genetic constraints on deposits from this belt. Suoi Thau is one of the representative Cu deposits associated with granitic intrusion. The deposit consists of ore bodies in altered granite or along the contact zone between granite and Proterozoic meta-sedimentary rocks. The Cu-bearing intrusion is sub-alkaline I-type granite. It has a zircon U-Pb age of ~776 Ma, and has subduction-related geochemical signatures. Geochemical analysis reveals that the intrusion may be formed by melting of mafic lower crust in a subduction regime. Three stages of alteration and mineralization are identified in the Suoi Thau deposit, i.e., potassic alteration; silicification and Cu mineralization; and phyllic alteration. Two-phase aqueous fluid inclusions in quartz from silicification stage show wide ranges of homogenization temperatures （140-383℃） and salinities （4.18wt%- 19.13wt%）. The high temperature and high salinity natures of some inclusions are consistent with a magmatic derivation of the fluids, which is also supported by the H-O-S isotopes. Fluids in quartz have JD values of-41.9‰ to -68.8%. The fluids in isotopic equilibrium with quartz have j180 values ranging from 7.9‰ to 9.2%. These values are just plotted in the compositional field of magmatie- hydrothermal fluids in the ~Dwater versus jlSOwater diagram. Sulfide minerals have relatively uniform j34S values from 1.84%o to 3.57%0, which is supportive of a magmatic derivation of sulfur. The fluid inclusions with relatively low temperatures and salinities most probably represent variably cooled magmatic-hydrothermal fluids. The magmatic derivation of fluids and the close spatial relationship between Cu ore bodies and intrusion suggest that the Cu mineralization most likely had a genetic association with granite. The Suoi Thau deposit, together with other deposits in the region, may define a Neoproterozoic subduct

关键词： Suoi Thau deposit Fan Si Pan belt copper ore deposit subduction related mineralization

Exponentially Bounded C-semigroup and the Cauchy Initial Value Problems in Complete Random Normed Modules

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Acta Mathematica Sinica,English Series 2024年第9期40卷 2195-2212页

作者： Son TA cong Thang dang HUNG Oanh Le THI Department of Mathematics University of ScienceVietnam National University 334 Nguyen TraiThanh XuanHanoiVietnam Faculty of Natural Sciences Hong Duc University565 Quang TrungDong VeThanh HoaVietnam

In this paper,the notion of C-semigroup of continuous module homomorphisms on a complete random normal(RN)module is introduced and *** existence and uniqueness of solution to the Cauchy problem with respect to exponen... 详细信息

关键词： C-semigroup Cauchy problem random normed modules L^(0)-Lipschitz

Prediction of the precessing vortex core in the Francis-99 draft tube under off-design conditions by using Liutex/Rortex method

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Journal of Hydrodynamics 2020年第3期32卷 623-628页

作者： cong Trieu tran Xin-ping Long Bin Ji Chaoqun Liu State Key Laboratory of Water Resources and Hydropower Engineering Science Wuhan UniversityWuhan 430072China School of Power and Mechanical Engineering Wuhan UniversityWuhan 430072China Facullty of Hydraulic Engineering National University of Civil Engineering 55 GiaiPhongHanoiVietnam Department of Mathematics University of Texas at ArlingtonArlington 76019USA

The turbulent flow in the draft tube of a Francis turbine is very complicated while working under off-design conditions. Although the off-design conditions were widely studied, the vortex core line in the draft tube of a Francis turbine with splitter blades is not well understood, especially the vortex rope property. This letter presents a prediction of the behavior of the vortex rope in the draft tube of the Francis-99 turbine obtained by the computational fluid dynamics (CFD), where the Liutex/Rortex method, as the most recent vortex definition, is applied to analyze the periodical precession of the vortex rope in the draft tube cone. The advantage of this Liutex/Rortex method is shown by its enhanced ability to represent the vortex rope structurewith the vortex-core lines. Furthermore, since it seems to be very hard to define a sharp boundary surface for the whole vortex structure, it is advantageousfocusing only on the vortex core line,by which different vortex structures can be clearly differentiated. The evolution of the vortex core and the process of the vortex breakdown in the draft tube are revealed, which might help to comprehend the development of the turbulent flow in the draft tube.

关键词： Cavitating vortex rope Francis turbine Liutex/Rortex method off-design condition vortex core line

Fe(Ⅱ)-mediated transformation of schwertmannite associated with calcium from acid mine drainage treatment

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Journal of Environmental Sciences 2023年第4期126卷 612-620页

作者： cong Fan Chuling Guo Wei Chen Guining Lu Yu Shen Zhi dang National Research Base of Intelligent Manufacturing Service Chongqing Technology and Business UniversityChongqing 400067China School of Environment and Energy South China University of TechnologyGuangzhou 510006China The Key Laboratory of Pollution Control and Ecosystem Restoration in Industry Clusters Ministry of EducationSouth China University of TechnologyGuangzhou 510006China Chongqing Key Laboratory of Environmental Materials and Remediation Technologies Chongqing University of Arts and SciencesChongqing 402160China

Schwertmannite is an important Fe(Ⅲ)-oxyhydroxysulfate in acid mine drainage (AMD) polluted areas and its stability depends on surrounding environmental factors and previously bound *** treatment and neutralization of AMD normally involve the use of lime,which leads to the discharge of abundant Ca in the mining *** an environmental disturbance brings up an important and less considered problem of how the reductive transformation of schwertmannite associated with coexisting Ca ***,the Fe(Ⅱ)-mediated transformation of Ca-adsorbed schwertmannite and subsequent Ca repartitioning behaviors were *** showed that adsorbed Ca had a weak inhibitory effect on Fe(Ⅱ)-mediated schwertmannite *** of SO_(4)2-and SEM images both indicated that transformation rates of schwertmannite decreased under the influence of adsorbed *** patterns indicated that adsorbed Ca altered schwertmannite transformation pathways and product compositions upon treatment with 0.4 mmol/L Fe(Ⅱ).The end products of Sch notably contained both goethite and lepidocrocite;however,transformation products of SchCa only contained goethite all *** 33.5%of the surface adsorbed-Ca was released into solution within 6 hr after Fe(Ⅱ) *** Ca behaved in a“first release and then im-mobilization”manner,which indicated dissolution and secondary mineralization drove Ca migration during the Fe(Ⅱ)-mediated transformation of *** Ca blocked the surface sites for subsequent Fe(Ⅱ) adsorption,limited the Fe(Ⅱ)-Fe(Ⅲ) ETAE,and decreased the transformation *** work sheds light on the complex geochemical behavior of schwertmannite under the influences of environmental perturbations in AMD environments.

关键词： Acid mine drainage Schwertmannite Calcium Fe(II) transformation

LINEARLY CONVERGENT FIRST-ORDER ALGORITHMS FOR SEMIDEFINITE PROGRAMMING

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Journal of Computational Mathematics 2017年第4期35卷 452-468页

作者： cong D. dang Guanghui Lan Zaiwen Wen Department of Industrial and Systems Engineering University of Florida Gainesville FL 32611 H. Milton Stewart School of Industrial and Systems Engineering Georgia Institute of TechnologyAtlanta GA 30332 USA Beijing International Center for Mathematical Research Peking University Beijing 100871 China

In this paper, we consider two different formulations （one is smooth and the other one is nonsmooth） for solving linear matrix inequalities （LMIs）, an important class of semidefinite programming （SDP）, under a certain Slater constraint qualification assumption. We then propose two first-order methods, one based on subgradient method and the other based on Nesterov＇s optimal method, and show that they converge linearly for solving these formulations. Moreover, we introduce an accelerated prox-level method which converges linearly uniformly for both smooth and non-smooth problems without requiring the input of any problem parameters. Finally, we consider a special case of LMIs, i.e., linear system of inequalities, and show that a linearly convergent algorithm can be obtained under a much weaker assumption.

关键词： Semi-definite Programming Linear Matrix Inequalities Error Bounds Linear Convergence