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Numerical Study on Local Flow and Heat Transfer Characteristics of Supercritical CO_(2) in PCHE with Sinusoidal Channels

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Journal of Thermal Science 2024年第1期33卷 41-55页

作者： wenZhexi LV Yigao LI qing WU Jinglin School of Energy Science and Engineering Central South UniversityChangsha 410083China

Local heat transfer and flow characteristics,which is crucial to the overall performance of supercritical CO_(2) recuperators,is rarely examined in details in reported *** this paper,the local heat transfer and flow characteristics of supercritical CO_(2) in sinusoidal channel printed circuit heat exchangers are numerically investigated under the working conditions of *** on the simplified physical model constituted by10 pitches,the variations of Re,heat flux,Nu,secondary flow and other relevant parameters along the flow direction are analyzed *** is further made between the high and low temperature recuperators(HTR and LTR).It's observed that the local heat transfer and flow characteristics vary greatly from the inlet to the outlet,especially in the *** of 127.5% and 61.7% can be observed on the cold side of the LTR for Re and heat transfer coefficient h, *** indicate that the temperature difference and heat transfer coefficient h should not be regarded as constant and the distribution of h should be carefully considered in the design of the *** complicated interactions among the varying thermophysical properties,buoyancy and the periodically changed centrifugal force are believed to be the key that shapes the flow ***,the changes of the wavy angle θ are found to have greater influence than the changes of mass flow rate in reshaping the flow field when θ>25°.Though gravity direction strongly affects the local heat transfer and flow characteristics,it's also found that the effects on the overall thermal-hydraulic performance are relatively *** the installation direction that yields a_y=g should better be avoided for the sinusoidal channel printed circuit heat exchanger.

关键词： printed circuit heat exchanger supercritical CO_(2) sinusoidal channel heat transfer recuperator

The AaBBX21–AaHY5 module mediates light-regulated artemisinin biosynthesis in Artemisia annua L.

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Journal of Integrative Plant Biology 2024年第8期66卷 1735-1751页

作者： Weizhi He Hang Liu Zhangkuanyu Wu qing Miao Xinyi hu Xin Yan Hangyu wen Yaojie Zhang Xueqing Fu Li Ren Kexuan Tang Ling Li Frontiers Science Center for Transformative Molecules Joint International ResearchLaboratory of Metabolic and Developmental SciencesKey Laboratory of Urban Agriculture(South)Ministry of AgriculturePlant Biotechnology Research CenterFudan-SJTU-Nottingham Plant Biotechnology R&D CenterSchool of Agriculture and BiologyShanghai Jiao Tong UniversityShanghai 200240China Institute for Agri-Food Standards and Testing Technology Shanghai Academy of Agricultural SciencesShanghai 201403China

The sesquiterpene lactone artemisinin is an important anti-malarial component produced by the glandular secretory trichomes of sweet wormwood(Artemisia annua L.).Light was previously shown to promote artemisinin production,but the underlying regulatory mechanism remains *** this study,we demonstrate that ELONGATED HYPOCOTYL5(HY5),a central transcription factor in the light signaling pathway,cannot promote artemisinin biosynthesis on its own,as the binding of AaHY5 to the promoters of artemisinin biosynthetic genes failed to activate their *** analysis and yeast two-hybrid screening revealed the B-box transcription factor AaBBX21 as a potential interactor with ***21 showed a trichome-specific expression ***,the AaBBX21–AaHY5 complex cooperatively activated transcription from the promoters of the downstream genes AaGSW1,AaMYB108,and AaORA,encoding positive regulators of artemisinin ***,AaHY5 and AaBBX21 physically interacted with the *** E3 ubiquitin ligase CONSTITUTIVELY PHOTOMORPHOGENIC 1(COP1).In the dark,AaCOP1 decreased the accumulation of AaHY5 and AaBBX21 and repressed the activation of genes downstream of the AaHY5–AaBBX21 complex,explaining the enhanced production of artemisinin upon light *** study provides insights into the central regulatory mechanism by which light governs terpenoid biosynthesis in the plant kingdom.

关键词： AaBBX21 AaHY5 AaCOP1 Artemisia annua L. artemisinin biosynthesis light

Physics of cavitation near particles

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Journal of Hydrodynamics 2024年第1期36卷 102-118页

作者： Jia-xin Yu Xiao-yu Wang Jun-wei Shen Jin-sen hu Xiang-qing Zhang Da-qing He Yu-ning Zhang Key Laboratory of Power Station Energy Transfer Conversion and System(Ministry of Education) School of Energy Power and Mechanical EngineeringNorth China Electric Power UniversityBeijing102206China

The combined effect of cavitation and silt abrasion presents a great challenge and threat to secure the operation and the efficiency of hydraulic machineries working in sediment-laden *** present paper critically reviews the current research progress on the interaction mechanisms of the bubbles and the ***,the analytical models including boundary treatment methods for predicting the jet dynamics of the bubble collapse near particles are ***,the bubble collapsing dynamics,jet dynamics and shock wave characteristics near particles are revealed both experimentally and ***,the bubble-particle-wall system is investigated with a focus on microjets.

关键词： Cavitation bubble particle jet shock wave

Machine learning methods for predicting the uniaxial compressive strength of the rocks:a comparative study

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Frontiers of Earth Science 2024年第2期18卷 400-411页

作者： Tao wen Decheng LI Yankun WANG Mingyi hu Ruixuan TANG School of Geosciences Yangtze UniversityWuhan 430100China Badong National Observation and Research Station of Geohazards China University of GeosciencesWuhan 430074China Jiacha County Branch of hubei Yangtze University Technology Development Co. LtdShannan 856499China

The uniaxial compressive strength(UCS)of rocks is a critical index for evaluating the mechanical properties and construction of an engineering rock mass classification *** most commonly used method for determining the UCS in laboratory settings is expensive and *** this reason,UCS can be estimated using an indirect determination method based on several simple laboratory tests,including point-load strength,rock density,longitudinal wave velocity,Brazilian tensile strength,Schmidt hardness,and shore *** this study,six data sets of indices for different rock types were utilized to predict the UCS using three nonlinear combination models,namely back propagation(BP),particle swarm optimization(PSO),and least squares support vector machine(LSSVM).Moreover,the best prediction model was examined and selected based on four performance prediction *** results reveal that the PSO–LSSVM model was more successful than the other two models due to its higher performance *** ratios of the predicted UCS to the measured UCS for the six data sets were 0.954,0.982,0.9911,0.9956,0.9995,and 0.993,*** results were more reasonable when the predicted ratio was close to a value of approximately 1.

关键词： uniaxial compressive strength particle swarm optimization least squares support vector machine prediction model prediction performance

Simulation Study on Constraining Gravitational Wave Propagation Speed by Gravitational Wave and Gamma-ray Burst Joint Observation on Binary Neutron Star Mergers

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Research in Astronomy and Astrophysics 2024年第8期24卷 42-51页

作者： Jin-hui Rao Shu-Xu Yi Lian Tao qing-wen Tang Department of Physics School of Physics and Materials ScienceNanchang UniversityNanchang 330031China Institute of High Energy Physics Chinese Academy of SciencesBeijing 100049China

Theories of modified gravity suggest that the propagation speed of gravitational waves(GW)v_gmay deviate from the speed of light c.A constraint can be placed on the difference between c and v_gwith a simple method that uses the arrival time delay between GW and electromagnetic wave simultaneously emitted from a burst *** simulated the joint observation of GW and short gamma-ray burst signals from binary neutron star merger events in different observation campaigns,involving advanced LIGO(aLIGO)in design sensitivity and Einstein Telescope(ET)joint-detected with Fermi/*** a result,the relative precision of constraint on v_gcan reach~10~(-17)(aLIGO)and~10^(-18)(ET),which are one and two orders of magnitude better than that from GW170817,*** continue to obtain the bound of graviton mass m_g≤7.1(3.2)×10~(-20)eV with aLIGO(ET).Applying the Standard-Model Extension test framework,the constraint on v_gallows us to study the Lorentz violation in the nondispersive,nonbirefringent limit of the gravitational *** obtain the constraints of the dimensionless isotropic coefficients S_(00)^(4)at mass dimension d=4,which are-1×10^(-15)

关键词： gravitational waves-(stars)gamma-ray burst general-stars neutron

Preparation and Tribological Properties of Onion-like Carbon/Waterborne Polyurethane Coatings

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China Petroleum Processing & Petrochemical Technology 2024年第2期26卷 108-120页

作者： Fei Xingpeng Jiang Wuhao wen Maosheng Xu Yong hu Kunhong hu Enzhu Department of Energy Materials and Chemical Engineering Hefei UniversityHefei 230601China Anhui Province Key Laboratory of Critical Friction Pair for Advanced Equipment Hefei 230088China

Rice husk powder was used as a carbon source in a high-temperature carbonization reaction for the production of rice husk ash(RHA).Under the catalysis of ferric nitrate,onion-like carbon(OLC)nanomaterial with a particle size of approximately 200 nm was successfully prepared and incorporated into waterborne polyurethane(WPU).The tribological properties of the coatings were determined using a controlled-atmosphere tribometer(WMT-2E)under dry-friction *** the friction test,the friction mechanism was investigated by characterizing the abrasive spot surfaces of the test samples using 3D laser microscopy and scanning electron microscopy/energy dispersive *** final results demonstrated that the thermal stability of WPU composite coatings containing various concentrations of OLC nanoparticles was significantly enhanced,binding forces between coatings and steel sheets increased,and hardness improved compared to pure WPU *** tests revealed a notable enhancement in the anti-wear properties of WPU coatings due to the presence of OLC ***,the wear rate of the 1.5%OLC/WPU coating was reduced by 45.3%.The coating’s anti-wear mechanism was attributed to the improvement in the mechanical properties of WPU due to OLC,as well as OLC’s participation in the formation of a transfer film under induced friction,which protected the matrix.

关键词： biomass carbon onion-like carbon waterborne polyurethane wear transfer films

Enhancement of comprehensive properties of Nb-Si based in-situ composites by Ho rare earth doping

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Rare Metals 2024年第9期43卷 4508-4520页

作者： Wei Wei Qi Wang Rui-Run Chen Chao-wen Zheng Yan-qing Su National Key Laboratory for Precision Hot Processing of Metals School of Materials Science and EngineeringHarbin Institute of TechnologyHarbin 150001China

This study examines the microstructure,mechanical properties(with a focus on room-temperature toughness),and oxidation resistance of Ho-doped NbDSi based in-situ *** base alloy consists of the coarse primary Nb_(5)Si_(3)phase and the Nb_(5)Si_(3)+Nbss(Nb solid solution)eutectic *** doping influences the solidification *** the Ho doping is higher than0.2 at%,the alloys transform into eutectic *** can be solid-solved in trace amounts in the Nbss ***,most of Ho forms a stable Ho oxide phase,which alleviates oxygen contamination problem to some ***,the interface separation between Ho oxide and other phases reduces the plastic deformation ***,with 0.4 at%Ho doping,the K_(Q)value is18.03 MPa·m^(1/2),which is 31.1%higher than that of the base *** strength of the Ho-doped alloys does not deteriorate with an increase in ***,the large network-like Ho_(2)O_(3)in the 0.8Ho alloy causes a decrease in toughness and *** addition,the Ho oxide phase effectively blocks the inward oxygen *** 0.8 at%Ho doping,the oxidation mass gain per unit area is 10.16 mg·cm^(2),which is 39.7%lower than that of the base alloy.

关键词： Nb-Si based composites Rare earth elements Ho Microstructure Properties

Review on the plastic instability of medium -Mn steels for identifying the formation mechanisms of Lüders and Portevin -Le Chatelier bands

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International Journal of Minerals,Metallurgy and Materials 2024年第6期31卷 1285-1297页

作者： Bin hu Han Sui qinghua wen Zheng Wang Alexander Gramlich Haiwen Luo School of Metallurgical and Ecological Engineering University of Science and Technology BeijingBeijing 100083China Steel Institute RWTH Aachen UniversityIntzestraße 152072 AachenGermany

Plastic instability,including both the discontinuous yielding and stress serrations,has been frequently observed during the tensile deformation of medium-Mn steels(MMnS)and has been intensively studied in recent ***,research results are controversial,and no consensus has been achieved regarding the ***,we first summarize all the possible factors that affect the yielding and flow stress serrations in MMnS,including the morphology and stability of austenite,the feature of the phase interface,and the deformation ***,we propose a universal mechanism to explain the conflicting experimental *** conclude that the discontinuous yielding can be attributed to the lack of mobile dislocation before deformation and the rapid dislocation multiplication at the beginning of plastic ***,the results show that the stress serrations are formed due to the pinning and depinning between dislocations and interstitial atoms in ***-induced martensitic transformation,influenced by the mechanical stability of austenite grain and deformation parameters,should not be the intrinsic cause of plastic ***,it can intensify or weaken the discontinuous yielding and the stress serrations by affecting the mobility and density of dislocations,as well as the interaction between the interstitial atoms and dislocations in austenite grains.

关键词： medium manganese steel discontinuous yielding stress serrations retained austenite dislocations

Photothermal properties of Cu@polycarbonate composites with strong localized surface plasmon resonances

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Nano Research 2024年第9期17卷 8513-8520页

作者： Fengyi Wang Jiangling He Junshan hu Zhihui Chen Yumeng Shi qing-hua Xu SZU-NUS Collaborative Innovation Center for Optoelectronic Science and Technology International Collaborative Laboratory of 2D Materials for Optoelectronics Science and Technology of Ministry of EducationInstitute of Microscale OptoelectronicsShenzhen UniversityShenzhen 518060China Department of Chemistry National University of Singapore3 Science Drive 3Singapore 117543Singapore College of Materials Science and Engineering Sichuan UniversityChengdu 610065China

Copper is relatively low cost and highly abundant compared with the well-studied noble metals such as gold and ***,the poor plasmonic and high susceptibility towards oxidation limit the study of its optical properties and applications as ***,copper nanoparticles@polycarbonate(Cu@PC)composites were prepared by using a facile one-step solvothermal *** Cu@PC composites have strong localized surface plasmon resonances(LSPR)due to that the PC shell can induce the particles to form many-particles system with different particle numbers,which not only lead to overlap and hybridize of the LSPR modes,but also shift the LSPR away from the interband transitions,and the PC layer also prevents the oxidation of Cu *** photothermal conversion efficiency of Cu@PC composites reaches 41.1%under 808 nm continuous wave(CW)laser irradiation which is higher than previously reported Cu nanomaterials that have been ***,the composites also have high photothermal ***,interfacial evaporator is prepared by assembling the Cu@PC composites on scouring sponge as light absorption layer which has>92.8%absorption in entire solar spectrum *** seawater evaporation rate is 3.177 kg·m^(-2)·h^(-1)with a E_(evaporator)/E_(water)of *** high evaporation rate interfacial evaporator with low cost,simple,and scalable approach shows great application value in the field of photothermal evaporation.

关键词： Cu nanoparticles localized surface plasmon resonances(LSPR) photothermal interfacial evaporation