检索结果-南通市图书馆

Journal of Thermal Science 2024年第1期33卷 348-367页

作者： LI Keying chi Jinling wANG Bo ZHANG Shijie Key Lab of Advanced energy and Power Institute of Engineering ThermophysicsChinese Academy of SciencesBeijing 100190China University of chinese Academy of Sciences Beijing 100049China School of Mechanical electronic&Information engineering China University of Mining&Technology-BeijingBeijing 100083China

exhaust gas recirculation control(eGRC),an inlet air heating technology,can be utilized in combination with inlet/variable guide vane control(IGV/VGVC) and fuel flow control(FFC) to regulate the load,thereby effectively improving the part-load(i.e.,off-design) performance of the gas turbine combined cycle(GTCC).In this study,the e-,F-,and H-Class eGR-GTCC design and off-design system models were established and validated to perform a comparative analysis of the part-load performance under the eGR-IGV-FFC and conventional IGV-FFC strategies in the e/F/H-Class *** show that eGR-IGV-FFC has considerable potential for the part-load performance enhancement and can show a higher combined cycle efficiency than IGV-FFC in the e-,F-,and H-Class ***,the part-load performance improvement in the corresponding GTCC was weakened for the higher class of the gas turbine because of the narrower load range of eGR action and the deterioration of the gas turbine ***,eGR-IGV-FFC was inferior to IGV-FFC in improving the performance at loads below 50% for the H-Class *** results obtained in this paper could help guide the application of eGR-IGV-FFC to enhance the part-load performance of various classes of GTCC systems.

关键词： e/F/H-Class gas turbine combined cycle performance improvement part-load conditions exhaust gas recirculation inlet/variable guide vane

A modern survey method for determining live loads based on multi-source and open-access data on the Internet

在线全文

学校读者我要写书评

暂无评论

Frontiers of Structural and Civil engineering 2024年第8期18卷 1135-1147页

作者： chi XU Jun CHeN Jie LI School of Civil engineering Tongji UniversityShanghai 200092China The State Key Laboratory on Disaster Reduction in Civil engineering Tongji UniversityShanghai 200092China

Sufficient survey data are required to describe the stochastic behaviors of live ***,due to manual and on-site operation required by traditional survey methods,traditional surveys face challenges like occupant resistance,high costs,and long implementation *** study proposes a new survey method to access live load data online and *** samples are acquired from multi-source,open-access and dynamically updated data on the *** change intervals,geometrical dimensions and object quantities are obtained from transaction information,building attributes and virtual reality models on real estate websites,*** object weights are collected from commodity information on e-commerce *** integration of the aforementioned data allows for the extraction of necessary statistics to describe a live load *** proposed method is applied to a live load survey in china,covering 20040 m^(2),with around 90000 samples acquired for object weights and load *** survey results reveal that about 70%−80%of the amplitude statistics are attributable to 1/6 of the total object types.

关键词： live load online survey method data acquisition data integration

chirality enables thermal magnon transistors

在线全文

维普期刊数据库

学校读者我要写书评

暂无评论

Science china(Physics,Mechanics & Astronomy) 2024年第4期67卷 161-166页

作者： Tao Yu Chengyuan Cai Gerrit e.w.Bauer School of Physics Huazhong University of Science and TechnologyWuhan 430074China .wPI-AIMR and Institute for Materials Research and SCIS Tohoku UniversitySendai 980-8577Japan Kavli Institute for Theoretical Sciences University of Chinese Academy of SciencesBeijing 100190China

we report a theory of thermal spin pumping into proximity magnets under a transverse-bias-driven heat flow of magnons in magnetic films when the dipolar coupling to the magnetic gate is tuned to be “chiral”. while there is no rectification of the magnon current in the film, we predict that chirality diverts a large percentage(50% for perfect chirality) of it into the gate. This transverse thermal spin pumping effect can be controlled by rotating the film magnetization and may help manage the heat flow in future magnonic circuits.

关键词： magnon chirality quantum transport transistor

Interplay of laser power and pore characteristics in selective laser melting of ZK60 magnesium alloys:A study based on in-situ monitoring and image analysis

在线全文

学校读者我要写书评

暂无评论

Journal of Magnesium and Alloys 2024年第4期12卷 1346-1366页

作者： weijie Xie Hau-Chung Man chi-wai Chan Department of Industrial and Systems engineering The Hong Kong Polytechnic UniversityHong KongChina School of Mechanical and Aerospace engineering Queen’s UniversityBelfast BT95AHUK Research Institute for Advanced Manufacturing The Hong Kong Polytechnic UniversityHong KongChina

This study offers significant insights into the multi-physics phenomena of the SLM process and the subsequent porosity characteristics of ZK60 Magnesium(Mg)***-speed in-situ monitoring was employed to visualise process signals in real-time,elucidating the dynamics of melt pools and vapour plumes under varying laser power conditions specifically between 40 w and 60 *** morphological analysis was performed using Scanning-electron Microscopy(SeM),demonstrating a critical correlation between laser power and pore *** laser power led to increased pore coverage,whereas a denser structure was observed at higher laser *** laser power influence on porosity was further confirmed via Optical Microscopy(OM)conducted on both top and cross-sectional surfaces of the *** increase in laser power resulted in a decrease in pore coverage and pore size,potentially leading to a denser printed part of Mg alloy.X-ray Computed Tomography(XCT)augmented these findings by providing a 3D volumetric representation of the sample internal structure,revealing an inverse relationship between laser power and overall pore *** laser power appeared to favour the formation of interconnected pores,while a reduction in interconnected pores and an increase in isolated pores were observed at higher *** interplay between melt pool size,vapour plume effects,and laser power was found to significantly influence the resulting porosity,indicating a need for effective management of these factors to optimise the SLM process of Mg alloys.

关键词： Selective laser melting(SLM) Magnesium(Mg)alloys Biodegradable implants Porosity In-situ monitoring

Particle segregation mechanism of S–D system in a rotating drum

在线全文

学校读者我要写书评

暂无评论

Particuology 2024年第10期93卷 300-308页

作者： erliang Xiao wei Zhang Zhipeng chi Ran Li Hui Yang School of Optical-electricaland Computer engineering University of Shanghai for Science and Technology Shanghai 200093Chin Collegeof Medical instrumentation hanghai Universty of Medicine&Health ScienceShanghaiChina

Complex segregation occurs in a binary particle system with differing particle sizes and densities,particularly when the larger particles are heavier(S–D system,i.e.,size minus density system).Predicting the segregation pattern driven by multiple mechanisms simultaneously is often *** study explores the segregation mechanisms in a quasi-2D circular drum containing a S–D system,realizing a transition between the S-core and Core-and-band patterns by adjusting the drum rotation *** the transition of the segregation pattern,only the S-core pattern chiefly driven by the percolation mechanism is initially *** the rotation speed increases,the buoyancy mechanism and particle diffusion gradually strengthen,jointly driving the formation of the Core-and-band pattern.A dimensionless strength ratio,λ=H/h,where H and h respectively represent the diffusion and buoyancy strengths at length scales,is introduced to elucidate this *** Core-and-band pattern emerges whenλreached 1.4.

关键词： Particle segregation S-Dsystem Segregationmechanisms competition Segregation pattern Rotating drum

estimation of the anisotropy of hydraulic conductivity through 3D fracture networks using the directional geological entropy

在线全文

维普期刊数据库

学校读者我要写书评

暂无评论

International Journal of Mining Science and Technology 2024年第2期34卷 137-148页

作者： Chuangbing Zhou Zuyang Ye chi Yao Xincheng Fan Feng Xiong School of Infrastructure engineering Nanchang UniversityNanchang 330031China b School of Resource and environmental engineering Wuhan University of Science and TechnologyWuhan 430081China School of engineering China University of GeosciencesWuhan 430074China

with an extension of the geological entropy concept in porous media,the approach called directional entrogram is applied to link hydraulic behavior to the anisotropy of the 3D fracture networks.A metric called directional entropic scale is used to measure the anisotropy of spatial order in different *** with the traditional connectivity indexes based on the statistics of fracture geometry,the directional entropic scale is capable to quantify the anisotropy of connectivity and hydraulic conductivity in heterogeneous 3D fracture *** to the numerical analysis of directional entrogram and fluid flow in a number of the 3D fracture networks,the hydraulic conductivities and entropic scales in different directions both increase with spatial order(i.e.,trace length decreasing and spacing increasing)and are independent of the dip *** a result,the nonlinear correlation between the hydraulic conductivities and entropic scales from different directions can be unified as quadratic polynomial function,which can shed light on the anisotropic effect of spatial order and global entropy on the heterogeneous hydraulic behaviors.

关键词： 3D fracture network Geological entropy Directional entropic scale Anisotropy Hydraulic conductivity

Space debris environment engineering model 2019:Algorithms improvement and comparison with ORDeM 3.1 and MASTeR-8

在线全文

学校读者我要写书评

暂无评论

chinese Journal of Aeronautics 2024年第5期37卷 392-409页

作者： Yuyan LIU Runqiang chi Baojun PANG HU Diqi wuxiong CAO Dongfang wANG School of Astronautics Harbin Institute of TechnologyHarbin 150001China College of Safety Science&engineering Civil Aviation University of ChinaTianjin 300300China

As an essential tool for realistic description of the current or future debris environment,the Space Debris environment engineering Model(SDeeM)has been developed to provide support for risk assessment of *** contrast with SDeeM2015,SDeeM2019,the latest version,extends the orbital range from the Low earth Orbit(LeO)to Geosynchronous Orbit(GeO)for the years *** this paper,improved modeling algorithms used by SDeeM2019 in propagating simulation,spatial density distribution,and spacecraft flux evaluation are *** debris fluxes of SDeeM2019 are compared with those of three typical models,i.e.,SDeeM2015,Orbital Debris engineering Model 3.1(ORDeM 3.1),and Meteoroid and Space Debris Terrestrial environment Reference(MASTeR-8),in terms of two assessment *** orbital cases,including the Geostationary Transfer Orbit(GTO),Sun-Synchronous Orbit(SSO)and International Space Station(ISS)orbit,are selected for the spacecraft assessment mode,and the LeO region is selected for the spatial density assessment *** analysis indicates that compared with previous algorithms,the variable step-size orbital propagating algorithm based on semi-major axis control is more precise,the spatial density algorithm based on the second zonal harmonic of the non-spherical earth gravity(J_(2))is more applicable,and the result of the position-centered spacecraft flux algorithm is more *** comparison shows that SDeeM2019 and MASTeR-8 have consistent trends due to similar modeling processes,while the differences between SDeeM2019 and ORDeM 3.1 are mainly caused by different modeling approaches for uncatalogued debris.

关键词： SDeeM2019 Space debris propagating algorithm Spatial density algorithm ORDeM 3.1 MASTeR-8

Theoretical screening of cooperative N-bridged dual-atom sites for efficient electrocatalytic nitrogen reduction with remolding insight

在线全文

学校读者我要写书评

暂无评论

Nano Research 2024年第4期17卷 3413-3422页

作者： Huimei Chen Yan Yang chi Jiao Zhiwen Zhuo Junjie Mao Yan Liu Key Laboratory of Functional Molecular Solids Ministry of EducationCollege of Chemistry and Materials ScienceAnhui Normal UniversityWuhu 241002China

The electrocatalytic nitrogen reduction reaction(e-NRR)is a promising alternative method for the Haber–Bosch ***,it still faces many challenges in searching for high activity,stability,and selectivity catalysts and ascertaining the catalytic mechanism with complete ***,a series of graphene-based N-bridged dual-atom catalysts(M1-N-M2/NC)are systematically investigated via first-principle calculation and a high-throughput screening *** result unveils that N_(2) adsorption on M1-N-M2/NC in bridge-on adsorption mode can effectively break the scaling relationship on single-atom catalysts(SACs).Moreover,V-N-Ru/NC and V-N-Os/NC are systematically screened out as promising e-NRR catalysts,with extremely low limiting potentials of-0.20 and-0.18 V,***,the adsorption site competition between*N_(2) and*H,as well as the competitive twin reactions of hydrogen evolution reaction(HeR)on intermediates(N_(n)H_(m))during the e-NRR process,is systematically evaluated to form a remodeling insight for the reactions in mechanism,and the e-NRR of new proposed dual-atom catalysts(DACs)is strategically optimized for its high-efficiency performance potential via our remolding insight in e-NRR *** work provides new ideas and insights for the design and mechanism of e-NRR catalysts and an effective strategy for rapidly screening highly efficient e-NRR catalysts.

关键词： nitrogen reduction dual-atom catalysts high-throughput screening hydrogen evolution reaction density functional theory calculations

Significant annealing-induced hardening effect in nanolaminate d-nanotwinne d(CrCoNi)_(97.4)Al_(0.8)Ti_(1.8)me dium-entropy alloy by severe cold rolling

在线全文

维普期刊数据库

学校读者我要写书评

暂无评论

Journal of Materials Science & Technology 2024年第3期170卷 156-166页

作者： Shuqing Yuan Hui Fu Lei Qian chi Fai Cheung Xu-Sheng Yang State Key Laboratory of Ultra-precision Machining Technology Department of Industrial and Systems EngineeringThe Hong Kong Polytechnic UniversityHung HomKowloonHong KongChina Hong Kong Polytechnic University Shenzhen Research Institute Shenzhen 518060China

Due to the easy coarsening caused by poor thermal stability,the verified annealing-induced hardening in nanograined metals can only maintain at a relatively low-temperature *** this study,a nanolam-inated(CrCoNi)_(97.4)Al_(0.8)Ti_(1.8)medium-entropy alloy with an average lamellae thickness of∼20 nm embedded by thinner nanotwins was fabricated by severe cold rolling to achieve superior thermal *** with the conventional nanotwinned CrCoNi with nanotwins inside ultra-fined grains,the hier-archical nanolaminated-nanotwinned(CrCoNi)_(97.4)Al_(0.8)Ti_(1.8) exhibits a significant annealing-induced hard-ening effect,i.e.,hardness increasing from∼250 HV in the original specimen to∼500 HV in the cold-rolled status and finally∼630 HV after annealing at 600℃for 1 *** microstructure characterizations reveal that the reduced dislocation density and formation of L1_(2)ordered domain are mainly responsible for such hardening effect,which is facilitated by the effectively suppressed coarsening with annealing temperature,i.e.,slow detwinning process and well-retained low-angle nanolamellar *** coarsening mechanisms from the cold-rolled nanolamellae to the fully recrystallized micro-equiaxed structures under the annealing temperatures ranging from 400 to 800℃ were also elucidated by atomic observations.

关键词： Annealing-induced hardening Thermal stability Nanolaminated-nanotwinned structure CrCoNi Detwinning Grain boundary migration

Carbon nanotubes and hexagonal boron nitride nanosheets co-filled ethylene propylene diene monomer composites:Improved electrical property for cable accessory applications

在线全文

维普期刊数据库

学校读者我要写书评

暂无评论

High Voltage 2024年第3期9卷 546-555页

作者： Tiandong Zhang Huiduo Xu Chuanxian Dai Changhai Zhang Yongquan Zhang Qingguo chi School of electrical and electronic engineering Harbin University of Science and TechnologyHarbinChina

Rubber-based composites based on ethylene propylene diene monomer(ePDM)with excellent non-linear electrical conductivity are preferred to serve as reinforced insu-lation in cable accessories,which can self-adaptively regulate electric field distribution and avoid electric field concentration due to the non-linear *** conductive carbon nanotubes(CNT)are filled into ePDM to improve the non-linear conductivity,while the insulating hexagonal boron nitride nanosheets(h-BN)are used to reconcile the electric breakdown *** results show that with the increase of CNT loading content,the non-linear conductivity of CNT/h-BN/ePDM com-posites becomes more prominent,accompanying the decrease of threshold field strength and increase of non-linear ***,the electric breakdown strength of CNT/h-BN/ePDM composites seriously deteriorates due to the increase of CNT content and *** incorporating 10 wt.%h-BN into the com-posites,the reduction percentage of breakdown strength can be significantly lowered,which is 19.95%of neat ePDM and 13.74%of CNT/h-BN/ePDM composites at 70℃,*** COMSOL Multiphysics simulation results demonstrate that using the CNT/h-BN/ePDM composite as the reinforced insulation can eliminate the electric field concentration of the cable accessory as well as enable the cable accessory with good lightning shock resistance.

关键词： composites hexagonal boron