期刊文献+
共找到624,905篇文章
< 1 2 250 >
每页显示 20 50 100
Control of light-matter interactions in two-dimensional materials with nanoparticle-on-mirror structures
1
作者 Shasha Li Yini Fang Jianfang Wang 《Opto-Electronic Science》 2024年第7期1-19,共19页
Light–matter interactions in two-dimensional(2D)materials have been the focus of research since the discovery of graphene.The light–matter interaction length in 2D materials is,however,much shorter than that in bulk... Light–matter interactions in two-dimensional(2D)materials have been the focus of research since the discovery of graphene.The light–matter interaction length in 2D materials is,however,much shorter than that in bulk materials owing to the atomic nature of 2D materials.Plasmonic nanostructures are usually integrated with 2D materials to enhance the light–matter interactions,offering great opportunities for both fundamental research and technological applications.Nanoparticle-on-mirror(NPo M)structures with extremely confined optical fields are highly desired in this aspect.In addition,2D materials provide a good platform for the study of plasmonic fields with subnanometer resolution and quantum plasmonics down to the characteristic length scale of a single atom.A focused and up-to-date review article is highly desired for a timely summary of the progress in this rapidly growing field and to encourage more research efforts in this direction.In this review,we will first introduce the basic concepts of plasmonic modes in NPo M structures.Interactions between plasmons and quasi-particles in 2D materials,e.g.,excitons and phonons,from weak to strong coupling and potential applications will then be described in detail.Related phenomena in subnanometer metallic gaps separated by 2D materials,such as quantum tunneling,will also be touched.We will finally discuss phenomena and physical processes that have not been understood clearly and provide an outlook for future research.We believe that the hybrid systems of2D materials and NPo M structures will be a promising research field in the future. 展开更多
关键词 light-matter interactions nanoparticle-on-mirror structures plasmonic enhancement two-dimensional materials
下载PDF
EXPERIMENTAL STUDY ON COHERENT VORTEX STRUCTURES IN DIFFERENTIALLY ROTATING QUASI TWO DIMENSIONAL ZONAL FLOW
2
作者 何钰泉 梁宝社 刘书声 《Transactions of Tianjin University》 EI CAS 1998年第2期86-89,共4页
An experimental system for forming a rotating paraboloid shaped shallow water with a free surface was conducted to study coherent vortex structures in a differentially rotating quasi two dimensional zonal flow.Flow... An experimental system for forming a rotating paraboloid shaped shallow water with a free surface was conducted to study coherent vortex structures in a differentially rotating quasi two dimensional zonal flow.Flow visualization and laser light scattering techniques were used to obtain the information of spatial flow patterns.Experimental results show that the coexistence of Coriolis effect and strong shear in latitudinal zones may lead to formation of coherent vortices.Power spectra analysis and photographs which were taken in a reference frame rotating with the observed vortices also justified the emergence,drift and evolution of persistent vortices on the large scale.Locked vortex state manifests the cyclone and anticyclone asymmetry. 展开更多
关键词 coherent structure rotating shallow water shear flow
下载PDF
3D Printing of Tough Hydrogel Scaffolds with Functional Surface Structures for Tissue Regeneration
3
作者 Ke Yao Gaoying Hong +11 位作者 Ximin Yuan Weicheng Kong Pengcheng Xia Yuanrong Li Yuewei Chen Nian Liu Jing He Jue Shi Zihe Hu Yanyan Zhou Zhijian Xie Yong He 《Nano-Micro Letters》 SCIE EI CAS 2025年第2期18-45,共28页
Hydrogel scaffolds have numerous potential applications in the tissue engineering field.However,tough hydrogel scaffolds implanted in vivo are seldom reported because it is difficult to balance biocompatibility and hi... Hydrogel scaffolds have numerous potential applications in the tissue engineering field.However,tough hydrogel scaffolds implanted in vivo are seldom reported because it is difficult to balance biocompatibility and high mechanical properties.Inspired by Chinese ramen,we propose a universal fabricating method(printing-P,training-T,cross-linking-C,PTC&PCT)for tough hydrogel scaffolds to fill this gap.First,3D printing fabricates a hydrogel scaffold with desired structures(P).Then,the scaffold could have extraordinarily high mechanical properties and functional surface structure by cycle mechanical training with salting-out assistance(T).Finally,the training results are fixed by photo-cross-linking processing(C).The tough gelatin hydrogel scaffolds exhibit excellent tensile strength of 6.66 MPa(622-fold untreated)and have excellent biocompatibility.Furthermore,this scaffold possesses functional surface structures from nanometer to micron to millimeter,which can efficiently induce directional cell growth.Interestingly,this strategy can produce bionic human tissue with mechanical properties of 10 kPa-10 MPa by changing the type of salt,and many hydrogels,such as gelatin and silk,could be improved with PTC or PCT strategies.Animal experiments show that this scaffold can effectively promote the new generation of muscle fibers,blood vessels,and nerves within 4 weeks,prompting the rapid regeneration of large-volume muscle loss injuries. 展开更多
关键词 3D printing Tough hydrogel scaffold Functional surface structure Tissue regeneration BIOMATERIALS
下载PDF
Emerging structures and dynamic mechanisms ofγ-secretase for Alzheimer’s disease
4
作者 Yinglong Miao Michael S.Wolfe 《Neural Regeneration Research》 SCIE CAS 2025年第1期174-180,共7页
γ-Secretase,called“the proteasome of the membrane,”is a membrane-embedded protease complex that cleaves 150+peptide substrates with central roles in biology and medicine,including amyloid precursor protein and the ... γ-Secretase,called“the proteasome of the membrane,”is a membrane-embedded protease complex that cleaves 150+peptide substrates with central roles in biology and medicine,including amyloid precursor protein and the Notch family of cell-surface receptors.Mutations inγ-secretase and amyloid precursor protein lead to early-onset familial Alzheimer’s disease.γ-Secretase has thus served as a critical drug target for treating familial Alzheimer’s disease and the more common late-onset Alzheimer’s disease as well.However,critical gaps remain in understanding the mechanisms of processive proteolysis of substrates,the effects of familial Alzheimer’s disease mutations,and allosteric modulation of substrate cleavage byγ-secretase.In this review,we focus on recent studies of structural dynamic mechanisms ofγ-secretase.Different mechanisms,including the“Fit-Stay-Trim,”“Sliding-Unwinding,”and“Tilting-Unwinding,”have been proposed for substrate proteolysis of amyloid precursor protein byγ-secretase based on all-atom molecular dynamics simulations.While an incorrect registry of the Notch1 substrate was identified in the cryo-electron microscopy structure of Notch1-boundγ-secretase,molecular dynamics simulations on a resolved model of Notch1-boundγ-secretase that was reconstructed using the amyloid precursor protein-boundγ-secretase as a template successfully capturedγ-secretase activation for proper cleavages of both wildtype and mutant Notch,being consistent with biochemical experimental findings.The approach could be potentially applied to decipher the processing mechanisms of various substrates byγ-secretase.In addition,controversy over the effects of familial Alzheimer’s disease mutations,particularly the issue of whether they stabilize or destabilizeγ-secretase-substrate complexes,is discussed.Finally,an outlook is provided for future studies ofγ-secretase,including pathways of substrate binding and product release,effects of modulators on familial Alzheimer’s disease mutations of theγ-secretase-substrate complexes.Comprehensive understanding of the functional mechanisms ofγ-secretase will greatly facilitate the rational design of effective drug molecules for treating familial Alzheimer’s disease and perhaps Alzheimer’s disease in general. 展开更多
关键词 Alzheimer’s disease amyloid precursor protein cryo-EM structures drug design intramembrane proteolysis molecular dynamics NOTCH
下载PDF
Designing Electronic Structures of Multiscale Helical Converters for Tailored Ultrabroad Electromagnetic Absorption
5
作者 Zhaobo Feng Chongbo Liu +7 位作者 Xin Li Guangsheng Luo Naixin Zhai Ruizhe Hu Jing Lin Jinbin Peng Yuhui Peng Renchao Che 《Nano-Micro Letters》 SCIE EI CAS 2025年第1期439-455,共17页
Atomic-scale doping strategies and structure design play pivotal roles in tailoring the electronic structure and physicochemical property of electromagnetic wave absorption(EMWA)materials.However,the relationship betw... Atomic-scale doping strategies and structure design play pivotal roles in tailoring the electronic structure and physicochemical property of electromagnetic wave absorption(EMWA)materials.However,the relationship between configuration and electromagnetic(EM)loss mechanism has remained elusive.Herein,drawing inspiration from the DNA transcription process,we report the successful synthesis of novel in situ Mn/N co-doped helical carbon nanotubes with ultrabroad EMWA capability.Theoretical calculation and EM simulation confirm that the orbital coupling and spin polarization of the Mn–N4–C configuration,along with cross polarization generated by the helical structure,endow the helical converters with enhanced EM loss.As a result,HMC-8 demonstrates outstanding EMWA performance,achieving a minimum reflection loss of−63.13 dB at an ultralow thickness of 1.29 mm.Through precise tuning of the graphite domain size,HMC-7 achieves an effective absorption bandwidth(EAB)of 6.08 GHz at 2.02 mm thickness.Furthermore,constructing macroscale gradient metamaterials enables an ultrabroadband EAB of 12.16 GHz at a thickness of only 5.00 mm,with the maximum radar cross section reduction value reaching 36.4 dB m2.This innovative approach not only advances the understanding of metal–nonmetal co-doping but also realizes broadband EMWA,thus contributing to the development of EMWA mechanisms and applications. 展开更多
关键词 Metal-nonmetal co-doping 3d-2p orbital coupling Spin polarization Helical structure Broadband EM wave absorption
下载PDF
High-speed autopolarization synchronization modulation three-dimensional structured illumination microscopy 被引量:2
6
作者 Yaning Li Ruijie Cao +6 位作者 Wei Ren Yunzhe Fu Yiwei Hou Suyi Zhong Karl Zhanghao Meiqi Li Peng Xi 《Advanced Photonics Nexus》 2024年第1期1-10,共10页
In recent years,notable progress has been achieved in both the hardware and algorithms of structured illumination microscopy(SIM).Nevertheless,the advancement of three-dimensional structured illumination microscopy(3D... In recent years,notable progress has been achieved in both the hardware and algorithms of structured illumination microscopy(SIM).Nevertheless,the advancement of three-dimensional structured illumination microscopy(3DSIM)has been impeded by challenges arising from the speed and intricacy of polarization modulation.We introduce a high-speed modulation 3DSIM system,leveraging the polarizationmaintaining and modulation capabilities of a digital micromirror device(DMD)in conjunction with an electrooptic modulator.The DMD-3DSIM system yields a twofold enhancement in both lateral(133 nm)and axial(300 nm)resolution compared to wide-field imaging and can acquire a data set comprising 29 sections of 1024 pixels×1024 pixels,with 15 ms exposure time and 6.75 s per volume.The versatility of the DMD-3DSIM approach was exemplified through the imaging of various specimens,including fluorescent beads,nuclear pores,microtubules,actin filaments,and mitochondria within cells,as well as plant and animal tissues.Notably,polarized 3DSIM elucidated the orientation of actin filaments.Furthermore,the implementation of diverse deconvolution algorithms further enhances 3D resolution.The DMD-based 3DSIM system presents a rapid and reliable methodology for investigating biomedical phenomena,boasting capabilities encompassing 3D superresolution,fast temporal resolution,and polarization imaging. 展开更多
关键词 digital micromirror device electro-optic modulation POLARIZATION three-dimensional structured illumination microscopy
下载PDF
Three-dimensional structural models,evolution and petroleum geological significances of transtensional faults in the Ziyang area,central Sichuan Basin,SW China
7
作者 TIAN Fanglei GUO Tonglou +6 位作者 HE Dengfa GU Zhanyu MENG Xianwu WANG Renfu WANG Ying ZHANG Weikang LU Guo 《Petroleum Exploration and Development》 SCIE 2024年第3期604-620,共17页
With drilling and seismic data of Transtensional(strike-slip)Fault System in the Ziyang area of the central Sichuan Basin,SW China plane-section integrated structural interpretation,3-D fault framework model building,... With drilling and seismic data of Transtensional(strike-slip)Fault System in the Ziyang area of the central Sichuan Basin,SW China plane-section integrated structural interpretation,3-D fault framework model building,fault throw analyzing,and balanced profile restoration,it is pointed out that the transtensional fault system in the Ziyang 3-D seismic survey consists of the northeast-trending F_(I)19 and F_(I)20 fault zones dominated by extensional deformation,as well as 3 sets of northwest-trending en echelon normal faults experienced dextral shear deformation.Among them,the F_(I)19 and F_(I)20 fault zones cut through the Neoproterozoic to Lower Triassic Jialingjiang Formation,presenting a 3-D structure of an“S”-shaped ribbon.And before Permian and during the Early Triassic,the F_(I)19 and F_(I)20 fault zones underwent at least two periods of structural superimposition.Besides,the 3 sets of northwest-trending en echelon normal faults are composed of small normal faults arranged in pairs,with opposite dip directions and partially left-stepped arrangement.And before Permian,they had formed almost,restricting the eastward growth and propagation of the F_(I)19 fault zone.The F_(I)19 and F_(I)20 fault zones communicate multiple sets of source rocks and reservoirs from deep to shallow,and the timing of fault activity matches well with oil and gas generation peaks.If there were favorable Cambrian-Triassic sedimentary facies and reservoirs developing on the local anticlinal belts of both sides of the F_(I)19 and F_(I)20 fault zones,the major reservoirs in this area are expected to achieve breakthroughs in oil and gas exploration. 展开更多
关键词 transtensional(strike-slip)fault three-dimensional structural model structural evolution petroleum geological significance Ziyang area Sichuan Basin
下载PDF
First‑principles study on electronic structure,optical and magnetic properties of rare earth elements X(X=Sc,Y,La,Ce,Eu)doped with two‑dimensional GaSe
8
作者 QIU Shenhao XIAO Qingquan +1 位作者 TANG Huazhu XIE Quan 《无机化学学报》 SCIE CAS CSCD 北大核心 2024年第11期2250-2258,共9页
The electronic structure,magnetic,and optical properties of two-dimensional(2D)GaSe doped with rare earth elements X(X=Sc,Y,La,Ce,Eu)were calculated using the first-principles plane wave method based on den-sity funct... The electronic structure,magnetic,and optical properties of two-dimensional(2D)GaSe doped with rare earth elements X(X=Sc,Y,La,Ce,Eu)were calculated using the first-principles plane wave method based on den-sity functional theory.The results show that intrinsic 2D GaSe is a p-type nonmagnetic semiconductor with an indi-rect bandgap of 2.6611 eV.The spin-up and spin-down channels of Sc-,Y-,and La-doped 2D GaSe are symmetric,they are non-magnetic semiconductors.The magnetic moments of Ce-and Eu-doped 2D GaSe are 0.908μ_(B)and 7.163μ_(B),which are magnetic semiconductors.Impurity energy levels appear in both spin-up and spin-down chan-nels of Eu-doped 2D GaSe,which enhances the probability of electron transition.Compared with intrinsic 2D GaSe,the static dielectric constant of the doped 2D GaSe increases,and the polarization ability is strengthened.The ab-sorption spectrum of the doped 2D GaSe shifts in the low-energy direction,and the red-shift phenomenon occurs,which extends the absorption spectral range.The optical reflection coefficient of the doped 2D GaSe is improved in the low energy region,and the improvement of Eu-doped 2D GaSe is the most obvious. 展开更多
关键词 first principle two-dimensional GaSe electronic structure magnetic property optical property
下载PDF
Three-dimensional thermohaline structure estimation derived from HY-2 satellite data over the Maritime Silk Road and its applications
9
作者 Zhiqiang Chen Xidong Wang +4 位作者 Xiangyu Wu Yuan Cao Zikang He Dakui Wang Jian Chen 《Acta Oceanologica Sinica》 SCIE CAS CSCD 2024年第5期41-53,共13页
Estimated ocean subsurface fields derived from satellite observations provide potential data sources for operational marine environmental monitoring and prediction systems.This study employs a statistic regression rec... Estimated ocean subsurface fields derived from satellite observations provide potential data sources for operational marine environmental monitoring and prediction systems.This study employs a statistic regression reconstruction method,in combination with domestic autonomous sea surface height and sea surface temperature observations from the Haiyang-2(HY-2)satellite fusion data,to establish an operational quasi-realtime three-dimensional(3D)temperature and salinity products over the Maritime Silk Road.These products feature a daily temporal resolution and a spatial resolution of 0.25°×0.25°and exhibit stability and continuity.We have demonstrated the accuracy of the reconstructed thermohaline fields in capturing the 3D thermohaline variations through comprehensive statistical evaluations,after comparing them against Argo observations and ocean analysis data from 2022.The results illustrate that the reconstructed fields effectively represent seasonal variations in oceanic subsurface structures,along with structural changes resulting from mesoscale processes,and the upper ocean’s responses to tropical cyclones.Furthermore,the incorporation of HY-2 satellite observations notably enhances the accuracy of temperature and salinity reconstructions in the Northwest Pacific Ocean and marginally improves salinity reconstruction accuracy in the North Indian Ocean when compared to the World Ocean Atlas 2018 monthly climatology thermohaline fields.As a result,the reconstructed product holds promise for providing quasi-real-time 3D temperature and salinity field information to facilitate fast decisionmaking during emergencies,and also offers foundational thermohaline fields for operational ocean reanalysis and forecasting systems.These contributions enhance the safety and stability of ocean subsurface activities and navigation. 展开更多
关键词 HY-2 satellite observations subsurface structures reconstruction Maritime Silk Road operational thermohaline product
下载PDF
A three-dimensional co-continuous network structure polymer electrolyte with efficient ion transport channels enabling ultralong-life all solid-state lithium metal batteries
10
作者 Meng Wang Hu Zhang +2 位作者 Yewen Li Ruiping Liu Huai Yang 《Journal of Energy Chemistry》 SCIE EI CAS CSCD 2024年第7期635-645,共11页
Solid polymer electrolytes(SPEs)have emerged as one of the most promising candidates for the construction of solid-state lithium batteries due to their excellent flexibility,scalability,and interface compatibility wit... Solid polymer electrolytes(SPEs)have emerged as one of the most promising candidates for the construction of solid-state lithium batteries due to their excellent flexibility,scalability,and interface compatibility with electrodes.Herein,a novel all-solid polymer electrolyte(PPLCE)was fabricated by the copolymer network of liquid crystalline monomers and poly(ethylene glycol)dimethacrylate(PEGDMA)acts as a structural frame,combined with poly(ethylene glycol)diglycidyl ether short chain interspersed serving as mobile ion transport entities.The preparaed PPLCEs exhibit excellent mechanical property and out-standing electrochemical performances,which is attributed to their unique three-dimensional cocontinuous structure,characterized by a cross-linked semi-interpenetrating network and an ionic liquid phase,resulting in a distinctive nanostructure with short-range order and long-range disorder.Remarkably,the addition of PEGDMA is proved to be critical to the comprehensive performance of the PPLCEs,which effectively modulates the microscopic morphology of polymer networks and improves the mechanical properties as well as cycling stability of the solid electrolyte.When used in a lithiumion symmetrical battery configuration,the 6 wt%-PPLCE exhibites super stability,sustaining operation for over 2000 h at 30 C,with minimal and consistent overpotential of 50 mV.The resulting Li|PPLCE|LFP solid-state battery demonstrates high discharge specific capacities of 160.9 and 120.1 mA h g^(-1)at current densities of 0.2 and 1 C,respectively.Even after more than 300 cycles at a current density of 0.2 C,it retaines an impressive 73.5%capacity.Moreover,it displayes stable cycling for over 180 cycles at a high current density of 0.5C.The super cycle stability may promote the application for ultralong-life all solid-state lithium metal batteries. 展开更多
关键词 Solid-state electrolyte Lithium-metal batteries Liquid crystalline polymer COPOLYMER 3D co-continuous structure Long cycle stability
下载PDF
Three-dimensional simulation of a Ka-band relativistic Cherenkov source with metal photonic-band-gap structures 被引量:9
11
作者 高喜 杨梓强 +4 位作者 亓丽梅 兰峰 史宗君 李大治 梁正 《Chinese Physics B》 SCIE EI CAS CSCD 2009年第6期2452-2458,共7页
This paper presents a three-dimensional particle-in-cell (PIC) simulation of a Ka-band relativistic Cherenkov source with a slow wave structure (SWS) consisting of metal photonic band gap (PBG) structures. In th... This paper presents a three-dimensional particle-in-cell (PIC) simulation of a Ka-band relativistic Cherenkov source with a slow wave structure (SWS) consisting of metal photonic band gap (PBG) structures. In the simulation, a perfect match layer boundary is employed to absorb passing band modes supported by the PBG lattice with an artificial metal boundary. The simulated axial field distributions in the cross section and surface of the SWS demonstrate that the device operates in the vicinity of the π point of a TM01-1ike mode. The Fourier transformation spectra of the axial fields as functions of time and space show that only a single frequency appears at 36.27 GHz, which is in good agreement with that of the intersection of the dispersion curve with the slow space charge wave generated on the beam. The simulation results demonstrate that the SWS has good mode selectivity. 展开更多
关键词 Cherenkov source slow wave structure photonic band gap three-dimensional particlein-cell
下载PDF
Three-dimensional Evolutionary Models of the Qiongxi Structures,Southwestern Sichuan Basin,China:Evidence from Seismic Interpretation and Geomorphology 被引量:17
12
作者 JIA Qiupeng JIA Dong +5 位作者 LUO Liang CHEN Zhuxin LI Yiquan DENG Fei SUN Shengsi LI Haibin 《Acta Geologica Sinica(English Edition)》 SCIE CAS CSCD 2009年第2期372-385,共14页
Fold terminations are key features in the study of compressional fault-related folds. Such terminations could be due to loss of displacement on the thrust fault or/and forming a lateral or oblique ramp. Thus, high-qua... Fold terminations are key features in the study of compressional fault-related folds. Such terminations could be due to loss of displacement on the thrust fault or/and forming a lateral or oblique ramp. Thus, high-quality seismic data would help unambiguously define which mechanism should be responsible for the termination of a given fault-related fold. The Qiongxi and Qiongxinan structures in the Sichuan Basin, China are examples of natural fault-propagation folds that possess a northern termination and a structural saddle between them. The folds/fault geometry and along-strike displacement variations are constrained by the industry 3-D seismic volume. We interpret that the plunge of the fold near the northern termination and the structural saddle are due to the loss of displacement along strike. The fault geometry associated with the northern termination changes from a flat-ramp at the crest of the Qiongxinan structure, where displacement is the greatest, to simply a ramp near the northern tip of the Qiongxi structure, without forming a lateral or oblique ramp. In this study, we also use the drainage pattern, embryonic structure preserved in the crest of the Qiongxinan structure and the assumption that displacement along a fault is proportional to the duration of thrusting to propose a model for the lateral propagation of the Qiongxinan and Qiongxi structures. Specifically, we suggest that the structure first initiated as an isolated fault ramp within brittle units. With increased shortening, the fault grows to link with lower detachments in weaker shale units to create a hybridized fault-propagation fold. Our model suggests a possible explanation for the lateral propagation history of the Qiongxinan and Qiongxi structures, and also provides an alternative approach to confirming the activity of the previous Pingluoba structure in the southwestern Sichuan Basin in the late Cenozoic. 展开更多
关键词 fault-propagation fold fold termination embryonic structure drainage pattern SICHUAN
下载PDF
Three-Dimensional Printing Conformal Cooling with Structural Lattices for Plastic Injection Molding
13
作者 Suping Shen Baris Burak Kanbur +1 位作者 Chenlong Wu Fei Duan 《Frontiers in Heat and Mass Transfer》 EI 2024年第2期397-415,共19页
The design of three-dimensional printing based conformal cooling channels(CCCs)in injection molding holds great significance.Compared to CCCs,conformal cooling(CC)cavity solutions show promise in delivering enhanced c... The design of three-dimensional printing based conformal cooling channels(CCCs)in injection molding holds great significance.Compared to CCCs,conformal cooling(CC)cavity solutions show promise in delivering enhanced cooling performance for plastic products,although they have been underexplored.In this research,CC cavity is designed within the mold geometry,reinforced by body-centered cubic(BCC)lattice structures to enhance mechanical strength.Three distinct BCC lattice variations have been integrated into the CC cavity:the BCC structure,BCC with cubes,and BCC with pillars.The thermal performances of the BCC lattice-added CC cavity are assessed numerically after experimental validation.To provide feasible solutions from viewpoints of thermal performances,various BCC lattice structure thicknesses are analyzed in the range of 0.8–1.2mm.Thermal simulation outcomes reveal that thicker lattice structures enhance mechanical strength but simultaneously lead to an increase in cooling time.Upon examining all the proposed CC cavity solutions supported by BCC,the cooling times range from 2.2 to 4 s,resulting in a reduction of 38.6%to 66.1%when compared to conventional straightdrilled channels.In contrast to CCCs,CC cavities have the potential to decrease the maximum temperature nonuniformity from 8.5 to 6 K.Nevertheless,the presence of lattice structures in CC cavity solutions results in an elevated pressure drop,reaching 2.8MPa,whereas the results for CCCs remain below2.1MPa. 展开更多
关键词 Conformal cooling cavity plastic injection additive manufacturing computational simulation thermal analysis lattice structure
下载PDF
WAVELET ANALYSIS OF COHERENT STRUCTURES IN A THREE-DIMENSIONAL MIXING LAYER 被引量:4
14
作者 林建忠 邵雪明 倪利民 《Acta Mechanica Sinica》 SCIE EI CAS CSCD 2002年第1期42-52,共11页
Wavelet analysis is applied to the results obtained by the direct numerical simulation of a three-dimensional (3D) mixing layer in order to investigate coherent structures in dimension of scale. First, 3D orthonormal ... Wavelet analysis is applied to the results obtained by the direct numerical simulation of a three-dimensional (3D) mixing layer in order to investigate coherent structures in dimension of scale. First, 3D orthonormal wavelet bases are constructed, and the corresponding decomposition algorithm is developed. Then the Navier-Stokes equations are transformed into the wavelet space and the architecture for multi-scale analysis is established. From this architecture, the coarse field images in different scales are obtained and some local statistical quantities are calculated. The results show that, with the development of a mixing layer, the energy spectrum densities for different wavenumbers increase and the energy is transferred from the average flow to vortex structures in different scales. Due to the non-linear interactions between different scales, cascade processes of energy are very complex. Because vortices always roll and pair at special areas, for a definite scale, the energy is obtained from other scales at some areas while it is transferred to other scales at other areas. In addition, energy dissipation and transfer always occur where an intense interaction between vortices exists. 展开更多
关键词 wavelet transforms numerical simulation mixing layer coherent structure
下载PDF
One-dimensional ZnS-based Hetero-,Core/shell and Hierarchical Nanostructures 被引量:3
15
作者 Ujjal K.Gautam Yoshio BANDO Dmitri GOLBERG 《Journal of Materials Science & Technology》 SCIE EI CAS CSCD 2008年第4期520-528,共9页
A focus of the current nanotechnology has shifted from routine fabrication of nanostructures to designing functional electronic devices and realizing their immense potentials for applications. Due to infusion of multi... A focus of the current nanotechnology has shifted from routine fabrication of nanostructures to designing functional electronic devices and realizing their immense potentials for applications. Due to infusion of multi-functionality into a single system, the utilization of hetero-, core/shell and hierarchical nanostructures has become the key issue for building such devices. ZnS, due to its direct wide bandgap, high index of refraction, high transparency in the visible range and intrinsic polarity, is one of the most useful semiconductors for a wide range of electronics applications. This article provides a dense review of the state-of-the-art research activities in one-dimensional (1D) ZnS-based hetero-, core/shell and hierarchical nanostructures. The particular emphasis is put on their syntheses and applications. 展开更多
关键词 HETEROstructures Core/shell Hierarchical structures ZNS NANODEVICES
下载PDF
Rational design and synthesis of one‐dimensional platinum‐based nanostructures for oxygen‐reduction electrocatalysis 被引量:8
16
作者 Huiting Niu Chenfeng Xia +5 位作者 Lei Huang Shahid Zaman Thandavarayan Maiyalagan Wei Guo Bo You Bao Yu Xia 《Chinese Journal of Catalysis》 SCIE EI CAS CSCD 2022年第6期1459-1472,共14页
Fuel cells have attracted extensive attention due to their high conversion efficiency and environmental friendliness.However,their wider application is limited by the poor activity and high cost of platinum(Pt),which ... Fuel cells have attracted extensive attention due to their high conversion efficiency and environmental friendliness.However,their wider application is limited by the poor activity and high cost of platinum(Pt),which is widely used as the cathode catalyst to overcome the slow kinetics associated with oxygen reduction reaction(ORR).Pt‐based composites with one‐dimensional(1D)nanoarchitectures demonstrate great advantages towards efficient ORR catalysis.This review focuses on the recent advancements in the design and synthesis of 1D Pt‐based ORR catalysts.After introducing the fundamental ORR mechanism and the advanced 1D architectures,their synthesis strategies(template‐based and template‐free methods)are discoursed.Subsequently,their morphology and structure optimization are highlighted,followed by the superstructure assembly using 1D Pt‐based blocks.Finally,the challenges and perspectives on the synthesis innovation,structure design,physical characterization,and theoretical investigations are proposed for 1D Pt‐based ORR nanocatalysts.We anticipate this study will inspire more research endeavors on efficient ORR nanocatalysts in fuel cell application. 展开更多
关键词 Fuel cells Oxygen reduction reaction ELECTROCATALYST Pt alloy One‐dimensional
下载PDF
The Shengli I Point Bar on the Yellow River Delta: Three-Dimensional Structures and Their Evolution 被引量:1
17
作者 钟建华 沈晓华 +8 位作者 倪晋仁 王冠民 温志峰 王夕宾 王海桥 李理 吴孔友 李勇 洪梅 《Acta Geologica Sinica(English Edition)》 SCIE CAS CSCD 2002年第4期463-477,共15页
Point bars are well developed on the Yellow River delta, an~ which theShengli I point bar is the most typical. The point bar, being about 4 km in length and several tensto more than 100 meters in width, is located on ... Point bars are well developed on the Yellow River delta, an~ which theShengli I point bar is the most typical. The point bar, being about 4 km in length and several tensto more than 100 meters in width, is located on the south side of the Shengli Bridge in KenliCounty, Dongying, Shandong. It is a typical fine-grained point bar with silt, which is predominant,some clay and minor plant debris and clay boulders. The Shengli I Point bar has complicated 3-Dstructures. Firstly, in a plane view, it comprises mainly eight sedimentary units, bar edge, baredge, bar platform, bar plain, bar channel, bar gully, bar pond and bar bay, developing side by sideand superimposed one by one m a complex way. Secondly, its vertical structures are very complex dueto the partial superimposition of the 8 sedimentary units. Besides hydatogenesis, very intensivewind erosion, eolian, ice and meltwater actions are also visible on the Shengli I point bar. Thecomplex form is made even more complicated because of the above co-actions. 展开更多
关键词 point bar three-dimensional structure EVOLUTION DELTA the Yellow River
下载PDF
Recent advances in one-dimensional nanostructures for energy electrocatalysis 被引量:5
18
作者 Ping Li Wei Chen 《Chinese Journal of Catalysis》 SCIE EI CAS CSCD 北大核心 2019年第1期4-22,共19页
Catalysts play decisive roles in determining the energy conversion efficiencies of energy devices.Up to now,various types of nanostructured materials have been studied as advanced electrocatalysts.This review highligh... Catalysts play decisive roles in determining the energy conversion efficiencies of energy devices.Up to now,various types of nanostructured materials have been studied as advanced electrocatalysts.This review highlights the application of one‐dimensional(1D)metal electrocatalysts in energy conversion,focusing on two important reaction systems-direct methanol fuel cells and water splitting.In this review,we first give a broad introduction of electrochemical energy conversion.In the second section,we summarize the recent significant advances in the area of 1D metal nanostructured electrocatalysts for the electrochemical reactions involved in fuel cells and water splitting systems,including the oxygen reduction reaction,methanol oxidation reaction,hydrogen evolution reaction,and oxygen evolution reaction.Finally,based on the current studies on 1D nanostructures for energy electrocatalysis,we present a brief outlook on the research trend in 1D nanoelectrocatalysts for the two clean electrochemical energy conversion systems mentioned above. 展开更多
关键词 One‐dimensional nanostructure Fuel cell Water splitting ELECTROCATALYSIS Energy conversion
下载PDF
Symplectic analysis for elastic wave propagation in two-dimensional cellular structures 被引量:5
19
作者 Xiu-Hui Hou Zi-Chen Deng +1 位作者 Jia-Xi Zhou Tie-Quan Liu 《Acta Mechanica Sinica》 SCIE EI CAS CSCD 2010年第5期711-720,共10页
On the basis of the finite element analysis, the elastic wave propagation in cellular structures is investigated using the symplectic algorithm. The variation principle is first applied to obtain the dual variables an... On the basis of the finite element analysis, the elastic wave propagation in cellular structures is investigated using the symplectic algorithm. The variation principle is first applied to obtain the dual variables and the wave propagation problem is then transformed into two-dimensional (2D) symplectic eigenvalue problems, where the extended Wittrick-Williams algorithm is used to ensure that no phase propagation eigenvalues are missed during computation. Three typical cellular structures, square, triangle and hexagon, are introduced to illustrate the unique feature of the symplectic algorithm in higher-frequency calculation, which is due to the conserved properties of the structure-preserving symplectic algorithm. On the basis of the dispersion relations and phase constant surface analysis, the band structure is shown to be insensitive to the material type at lower frequencies, however, much more related at higher frequencies. This paper also demonstrates how the boundary conditions adopted in the finite element modeling process and the structures' configurations affect the band structures. The hexagonal cells are demonstrated to be more efficient for sound insulation at higher frequencies, while the triangular cells are preferred at lower frequencies. No complete band gaps are observed for the square cells with fixed-end boundary conditions. The analysis of phase constant surfaces guides the design of 2D cellular structures where waves at certain frequencies do not propagate in specified directions. The findings from the present study will provide invaluable guidelines for the future application of cellular structures in sound insulation. 展开更多
关键词 Cellular structures Symplectic analysis Dispersion relation - Phase constant surface Sound insulation
下载PDF
Three-dimensional discrete element numerical simulation of Paleogene salt structures in the western Kuqa foreland thrust belt 被引量:3
20
作者 LI Jianghai ZHANG Yu +1 位作者 WANG Honghao WANG Dianju 《Petroleum Exploration and Development》 2020年第1期68-79,共12页
Taking the Paleogene salt strata in the west of Kuqa foreland thrust belt as study object, the deformation features of salt structure in the compression direction and perpendicular to the compression direction were ex... Taking the Paleogene salt strata in the west of Kuqa foreland thrust belt as study object, the deformation features of salt structure in the compression direction and perpendicular to the compression direction were examined to find out the control factors and formation mechanisms of the salt structures. By using the three-dimensional discrete element numerical simulation method, the formation mechanisms of typical salt structures of western Kuqa foreland thrust belt in Keshen and Dabei work areas were comprehensively analyzed. The simulation results show that the salt deformation in Keshen and Dabei work areas is of forward spread type, with deformation concentrated in the piedmont zone;the salt deformation is affected by the early uplift near the compression end, pre-existing basement faults, synsedimentary process and the initial salt depocenter;in the direction perpendicular to the compression direction, salt rocks near the compression end have strong lateral mobility with the velocity component moving towards the middle part, and the closer to the middle, the larger the velocity will be, so that salt rocks will aggregate towards the middle and deform intensely, forming complex folds and separation of salt structures from salt source, and local outcrop with thrust faults. Compared with 2 D simulation, 3 D simulation can analyze salt structures in the principal stress direction and direction perpendicular to the principal stress, give us a full view of the formation mechanisms of salt structures, and guide the exploration of oil and gas reservoirs related to salt structures. 展开更多
关键词 TARIM Basin KUQA Depression FORELAND THRUST belt salt structure THREE-dimensional discrete-element numerical simulation formation mechanism
下载PDF
上一页 1 2 250 下一页 到第
使用帮助 返回顶部