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Multi-objective optimization and evaluation of supercritical CO_(2) Brayton cycle for nuclear power generation

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Nuclear Science and Techniques 2024年第2期35卷 183-209页

作者： Guo-Peng yu Yong-Feng cheng Na Zhang Ping-Jian ming Sino-French Institute of Nuclear Engineering and Technology Sun Yat-Sen UniversityZhuhai 519082China School of Civil Engineering and Architecture East China Jiaotong UniversityNanchang 330013China

The supercritical CO_(2) Brayton cycle is considered a promising energy conversion system for Generation IV reactors for its simple layout,compact structure,and high cycle *** models of four Brayton cycle layouts are developed in this study for different reactors to reduce the cost and increase the thermohydraulic performance of nuclear power generation to promote the commercialization of nuclear *** analysis,multi-objective optimizations,and four decision-making methods are applied to obtain each Brayton scheme’s optimal thermohydraulic and economic *** show that for the same design thermal power scale of reactors,the higher the core’s exit temperature,the better the Brayton cycle’s thermo-economic *** the four-cycle layouts,the recompression cycle(RC)has the best overall performance,followed by the simple recuperation cycle(SR)and the intercooling cycle(IC),and the worst is the reheating cycle(RH).However,RH has the lowest total cost of investment(C_(tot))of$1619.85 million,and IC has the lowest levelized cost of energy(LCOE)of 0.012$/(kWh).The nuclear Brayton cycle system’s overall performance has been improved due to *** performance of the molten salt reactor combined with the intercooling cycle(MSR-IC)scheme has the greatest improvement,with the net output power(W_(net)),thermal efficiencyη_(t),and exergy efficiency(η_(e))improved by 8.58%,8.58%,and 11.21%,*** performance of the lead-cooled fast reactor combined with the simple recuperation cycle scheme was optimized to increase C_(tot) by 27.78%.In comparison,the internal rate of return(IRR)increased by only 7.8%,which is not friendly to investors with limited *** the nuclear Brayton cycle,the molten salt reactor combined with the recompression cycle scheme should receive priority,and the gas-cooled fast reactor combined with the reheating cycle scheme should be considered carefully.

关键词： Supercritical CO_(2)Brayton cycle Nuclear power generation Thermo-economic analysis Multi-objective optimization Decision-making methods

An improved initial rotor position estimation method using high-frequency pulsating voltage injection for PMSM

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Defence Technology（防务技术） 2024年第3期33卷 19-29页

作者： Yang Jiang ming cheng School of Electrical Engineering Southeast UniversityNanjing 210096China

High frequency pulsating voltage injection method is a good candidate for detecting the initial rotor position of permanent magnet synchronous ***,traditional methods require a large number of filters,which leads to the deterioration of system stability and dynamic *** order to solve these problems,a new signal demodulation method is proposed in this *** proposed new method can directly obtain the amplitude of high-frequency current,thus eliminating the use of filters,improving system stability and dynamic performance and saving the work of adjusting filter *** addition,a new magnetic polarity detection method is proposed,which is robust to current measurement ***,experiments verify the effectiveness of the method.

关键词： Initial position detection Signal demodulation algorithm Magnetic polarity detection Filter elimination

Enhanced thermoelectric and mechanical properties of Bi_(0.5)Sb_(1.5)Te_(3) alloy with dispersed yttrium oxide ceramic nanoparticles

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Rare Metals 2024年第4期43卷 1758-1768页

作者： Cun-cheng Li ming-Wei Zhang Ji-Wu Xin Lei Wei Wen-yu Zhao School of Materials Science and Engineering Shandong University of TechnologyZibo255000China School of Electrical and Electronic Engineering Nanyang Technological UniversitySingapore639798Singapore State Key Laboratory of Advanced Technology for Materials Synthesis and Processing Wuhan University of TechnologyWuhan430070China

Reducing thermal conductivity while avoiding adverse interfacial reactions during sintering is crucial for improving the thermoelectric performance of Bi_(2)Te_(3)based *** ceramic nanoparticles are good candidates for achieving this *** this study,we designed and prepared a series of p-type Bi_(0.5)Sb_(1.5)Te_(3)nanocomposites decorated with Y_(2)O_(3)ceramic nanoparticles via ball-milling dispersion and spark-plasma *** to the chemical stability of the ceramics,no traces of atomic doping or interfacial reactions were *** measurements revealed that the Y_(2)O_(3)nanoparticles distributed along the grain boundaries acted as energy-dependent carrier-filtering centers to improve the scattering parameter and Seebeck coefficient,contributing to the elevated power factor even with a decreased electrical ***,the incorporated Y_(2)O_(3)nanoparticles and various defect structures they induced effectively strengthened the phonon scattering and suppressed the lattice thermal ***,a peak figure of merit(ZT)of 1.23 at 313 K was achieved for 0.4%Y_(2)O_(3)/Bi_(0.5)Sb_(1.5)Te_(3),which is 13%higher than that of the *** addition,the Vickers hardness of the composite material was 35%higher than that of the *** study demonstrates the effectiveness of ceramic nanoparticles in synergistic ally improving the thermoelectric and mechanical properties,which may be further extended to other thermoelectric systems.

关键词： Bi_(0.5)Sb_(1.5)Te_3 alloy Y_(2)O_(3) ceramic nanoparticles Microstructures Thermoelectric performance Mechanical properties

Weak Merging Scenario of CLASH Cluster A209

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Research in Astronomy and Astrophysics 2024年第4期24卷 174-182页

作者： Wen-cheng Feng Heng yu Hai-Hui Zhao Xiao-Lan Hou Shu-Mei Jia cheng-Kui Li yu-Lin cheng Paolo Tozzi ming Sun Yong Chen Department of Physics and Institute of Theoretical Physics Nanjing Normal UniversityNanjing 210023China Key Laboratory of Particle Astrophysics Institute of High Energy PhysicsChinese Academy of SciencesBeijing 100049China Department of Astronomy Beijing Normal UniversityBeijing 100875China Department of Astronomy Yunnan UniversityKunming 650091China INAF—Osservatorio Astrofisico di Arcetri Largo E.Fermi50122 FirenzeItaly Department of Astronomy University of VirginiaP.O.Box 400325CharlottesvilleVA 22904-4325USA

We study the structural and dynamical properties of A209 based on Chandra and XMM-Newton *** obtain detailed temperature,pressure,and entropy maps with the contour binning method,and find a hot region in the NW *** X-ray brightness residual map and corresponding temperature profiles reveal a possible shock front in the NW direction and a cold front feature in the SE *** with the galaxy luminosity density map we propose a weak merger scenario.A young sub-cluster passing from the SE to NW direction could explain the optical subpeak,the intracluster medium temperature map,the X-ray surface brightness excess,and the X-ray peak offset together.

关键词： X rays:galaxies:clusters galaxies:clusters:intracluster medium galaxies:clusters:Abell 209

Dual Frequency Transformer for Efficient SDR-to-HDR Translation

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Machine Intelligence Research 2024年第3期21卷 538-548页

作者： Gang Xu Qibin Hou ming-ming cheng Tianjin Media Computing Center College of Computer ScienceNankai UniversityTianjin300000China

The SDR-to-HDR translation technique can convert the abundant standard-dynamic-range (SDR) media resources to high-dynamic-range (HDR) ones, which can represent high-contrast scenes, providing more realistic visual experiences. While recent vision Transformers have achieved promising performance in many low-level vision tasks, there are few works attempting to leverage Transformers for SDR-to-HDR translation. In this paper, we are among the first to investigate the performance of Transformers for SDR-to-HDR translation. We find that directly using the self-attention mechanism may involve artifacts in the results due to the inappropriate way to model long-range dependencies between the low-frequency and high-frequency components. Taking this into account, we advance the self-attention mechanism and present a dual frequency attention (DFA), which leverages the self-attention mechanism to separately encode the low-frequency structural information and high-frequency detail information. Based on the proposed DFA, we further design a multi-scale feature fusion network, named dual frequency Transformer (DFT), for efficient SDR-to-HDR translation. Extensive experiments on the HDRTV1K dataset demonstrate that our DFT can achieve better quantitative and qualitative performance than the recent state-of-the-art methods. The code of our DFT is made publicly available at https://***/CS-GangXu/DFT.

关键词： Standard-dynamic-range to high-dynamic-range(SDR-to-HDR)translation Transformer dual frequency attention(DFA) frequency-aware feature decomposition efficient model

Novel subtype of obesity influencing the outcomes of sleeve gastrectomy:Familial aggregation of obesity

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World Journal of Gastroenterology 2024年第13期30卷 1887-1898页

作者： Ze-yu Wang yun-Fei Qu Tian-ming yu Zeng-Lin Liu yu-Gang cheng ming-Wei Zhong San-yuan Hu Department of General Surgery The First Affiliated Hospital of Shandong First Medical University and Shandong Provincial Qianfoshan HospitalJinan 250000Shandong ProvinceChina Department of Postgraduate Shandong First Medical University and Shandong Academy of Medical SciencesJinan 250000Shandong ProvinceChina Department of General Surgery Shandong Provincial Qianfoshan HospitalCheeloo College of Medicine Shandong UniversityJinan 250000Shandong ProvinceChina State Key Laboratory of Integration and Innovation of Classic Formula and Modern Chinese Medicine Lunan Pharmaceutical Group Co.Ltd.Linyi 276005Shandong ProvinceChina

BACKGROUND Differences in the preoperative characteristics and weight loss outcomes after sleeve gastrectomy(SG)between patients with familial aggregation of obesity(FAO)and patients with sporadic obesity(SO)have not been *** To explore the impact of SG on weight loss and the alleviation of obesity-related comorbidities in individuals with *** A total of 193 patients with obesity who underwent SG were *** with FAO/SO were matched 1:1 by propensity score matching and were categorized into 4 groups based on the number of first-degree relatives with obesity(1 SO vs 1FAO,2SO vs 2FAO).The baseline characteristics,weight loss outcomes,prevalence of obesity-related comorbidities and incidence of major surgeryrelated complications were compared between *** We defined FAO as the presence of two or more first-degree relatives with *** with FAO did not initially show significant differences in baseline data,short-term postoperative weight loss,or obesity-related comorbidities when compared to patients with SO ***,distinctions between the two groups became evident at the two-year mark,with statistically significant differences in both percentage of total weight loss(P=0.006)and percentage of excess weight loss(P<0.001).The FAO group exhibited weaker remission of type 2 diabetes mellitus(T2DM)(P=0.031),hyperlipidemia(P=0.012),and non-alcoholic fatty liver disease(NAFLD)(P=0.003)as well as a lower incidence of acid reflux(P=0.038).CONCLUSION FAO patients is associated with decreased mid-to-long-term weight loss outcomes;the alleviation of T2DM,hyperlipidemia and NAFLD;and decreased incidence of acid reflux postoperatively.

关键词： Obesity Bariatric surgery Sleeve gastrectomy Family history Weight loss

A multi-mechanism numerical simulation model for CO_(2)-EOR and storage in fractured shale oil reservoirs

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Petroleum Science 2024年第3期21卷 1814-1828页

作者： yuan-Zheng Wang Ren-Yi Cao Zhi-Hao Jia Bin-yu Wang ming Ma Lin-Song cheng College of Petroleum Engineering China University of Petroleum(Beijing)Beijing102249China John&Willie Leone Department of Energy&Mineral Engineering The Pennsylvania State UniversityUniversity Park16802PA.USA

Under the policy background and advocacy of carbon capture,utilization,and storage(CCUS),CO_(2)-EOR has become a promising direction in the shale oil reservoir *** multi-scale pore structure distribution and fracture structure lead to complex multiphase flow,comprehensively considering multiple mechanisms is crucial for development and CO_(2) storage in fractured shale *** this paper,a multi-mechanism coupled model is developed by *** to the traditional Eclipse300 and MATLAB Reservoir Simulation Toolbox(MRST),this model considers the impact of pore structure on fluid phase behavior by the modified Peng—Robinson equation of state(PR-EOS),and the effect simultaneously radiate to Maxwell—Stefan(M—S)diffusion,stress sensitivity,the nano-confinement(NC)***,a modified embedded discrete fracture model(EDFM)is used to model the complex fractures,which optimizes connection types and half-transmissibility calculation approaches between non-neighboring connections(NNCs).The full implicit equation adopts the finite volume method(FVM)and Newton—Raphson iteration for discretization and *** model verification with the Eclipse300 and MRST is *** results show that the interaction between the mechanisms significantly affects the production performance and storage *** effect of molecular diffusion may be overestimated in oil-dominated(liquid-dominated)shale *** well spacing and injection gas rate are the most crucial factors affecting the production by sensitivity ***,the potential gas invasion risk is *** model provides a reliable theoretical basis for CO_(2)-EOR and sequestration in shale oil reservoirs.

关键词： CO_(2)-EOR CO_(2)storage Shale oil reservoir Complex fracture model Multiple mechanisms

Effects of Ta content on microstructure and oxidation behavior of AlCoCrFeNiYTa_(x)high entropy alloy

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Rare Metals 2024年第9期43卷 4462-4475页

作者： Cang Gu Jun-Hao Hu Jian-Bo Song cheng Xu ming-yu Hu yu-Xuan Zhang Jiang Tian Chao Li Jing Feng Faculty of Materials Science and Engineering Kunming University of Science and TechnologyKunming 650093China Department of Physics Hong Kong Baptist UniversityHong Kong 999077China

The oxidation behavior of the Al CoCrFeNiYTa_(x)high entropy alloy(HEA)doped with different Ta contents at 1100℃is *** this study,different reasons for the spallation of the oxide scales of HEAs without/with excessive Ta addition after 1000 h of oxidation are discussed,and the most suitable Ta doping content for this HEA is explored,in which the HEA exhibits both an exceptionally low oxidation rate,and the formation of oxide scales composed of intact a-Al_(2)O_(3).Meanwhile,it is found that the addition of Ta can effectively inhibit the phase transition of β phase,which makes the surface of the oxide scale *** combining our experimental results with Wagner–Hauffe theory,the influence of Ta drag effect on oxide scale growth is explained,which provides some theoretical guidance for the subsequent design of AlCoCrFeNi HEAs,and can lead to the development of thermal barrier coatings at higher service temperature.

关键词： High-entropy alloy Al_(2)O_(3)scales Oxidation Elements diffusion

Microstructure and property of laser additive manufactured alloy Ti-6Al-2V-1.5Mo-0.5Zr-0.3Si after aged at different temperatures

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Rare Metals 2024年第5期43卷 2275-2281页

作者： Guo-Chao Li Xu cheng Hua-ming Wang National Engineering Laboratory of Additive Manufacturing for Large Metallic Components and Engineering Research Center of Ministry of Education on Laser Direct Manufacturing for Large Metallic Components School of Materials Science and EngineeringBeihang UniversityBeijing 100191China

The solid solution and aging treatment for conventional manufacturing processes might not be suitable for laser additive manufactured titanium alloys due to the different lamellar *** this study,the influence of aging temperatures(600,700 and 800°C)on microstructure and mechanical properties of titanium alloy Ti-6Al-2V-1.5Mo-0.5Zr-0.3Si was *** results indicate that after solid solution treatment at 970°C followed by water quenching,the alloy mainly consists of coarsening lamellar a phase in martensite α' *** at 600°C will not change the size of primary lamellar α phase but lead to huge amount of secondary a phases(α_(s))generating with very fine *** increasing the aging temperature,the number of α_(s) decreases but with coarsened *** aged at 800°C,the width of the asphase reaches 350 nm,almost 7 times wider than that aged at 600°*** changing size of α_(s) obviously influences the property of the *** fine α_(s) leads to high strength and microhardness but low plasticity,and specimen aged at 700°C with suitable assize has the best comprehensive properties.

关键词： α+βtitanium alloy Laser additive manufacturing Solid solution and aging treatment Microstructure Room temperature tensile property