检索结果-南通市图书馆

A versatile model with three-dimensional triangular lattice for unconventional transport and various topological effects

在线全文

维普期刊数据库

学校读者我要写书评

暂无评论

National Science Review 2024年第1期11卷 204-214页

作者： Jing-Yang you gang Su Yuan Ping Feng Department of Physics National University of Singapore Kavli Institute for Theoretical Sciences and CAS Center for Excellence in Topological Quantum Computation University of Chinese Academy of Sciences Centre for Advanced 2D Materials National University of Singapore

The finite Berry curvature in topological materials can induce many subtle phenomena, such as the anomalous Hall effect(AHE), spin Hall effect(SHE), anomalous Nernst effect(ANE), non-linear Hall effect(NLHE) and bulk photovoltaic effects. To explore these novel physics as well as their connection and coupling, a precise and effective model should be developed. Here, we propose such a versatile model—a 3D triangular lattice with alternating hopping parameters, which can yield various topological phases,including kagome bands, triply degenerate fermions, double Weyl semimetals and so on. We reveal that this special lattice can present unconventional transport due to its unique topological surface states and the aforementioned topological phenomena, such as AHE, ANE, NLHE and the topological photocurrent effect. In addition, we also provide a number of material candidates that have been synthesized experimentally with this lattice, and discuss two materials, including a non-magnetic triangular system for SHE, NLHE and the shift current, and a ferromagnetic triangular lattice for AHE and ANE. Our work provides an excellent platform, including both the model and materials, for the study of Berry-curvature-related physics.

关键词： three-dimensional triangular lattice different topological phases various topological effects Berry curvature

Density-based ship detection in SAR images:Extension to a self-similarity perspective

在线全文

同方期刊数据库

学校读者我要写书评

暂无评论

Chinese Journal of Aeronautics 2024年第3期37卷 168-180页

作者： Xueqian WANG gang LI Zhizhuo JIANG Yu LIU you HE Department of Electronic Engineering Tsinghua UniversityBeijing 100084China Shenzhen International Graduate School Tsinghua UniversityShenzhen 518055China

Nonlocal self-similarity is an important property of Synthetic Aperture Radar(SAR)images to characterize the repetitiveness of features embodied by SAR images within nonlocal areas and has been used for enhancement of SAR images.Existing SAR ship detectors often independently handle small sub-images cropped from a large marine SAR image and do not exploit the nonlocal self-similarity therein.In this paper,we propose a new ship detector from the perspective of nonlocal self-similarity in SAR images to improve the ship detection performance,basically including three stages:prescreening,intra-cue calculation,and inter-cue calculation.In the prescreening stage,we design a new Histogram-based Density(HD)feature to rapidly select candidate sub-images potentially containing ship targets from a large SAR image.In the intra-cue calculation stage,target cues within a single candidate sub-image are extracted.In the inter-cue calculation stage,thanks to the nonlocal self-similarity among different candidate sub-images in terms of density features,we innovatively extract a weighted superpixel-HD map to obtain accumulated intracues across all the candidate sub-images.Finally,for each candidate sub-image,we fuse its inter-cue and intra-cue to obtain final detection results.Experimental results based on real SAR images show that our newly proposed method provides a better target-to-clutter contrast and ship detection performance than those of other state-of-the-art detection approaches.

关键词： Ship detection Synthetic aperture radar(SAR) Density Self-similarity Histogram

Electromagnetic fields in ultra-peripheral relativistic heavy-ion collisions

在线全文

学校读者我要写书评

暂无评论

Nuclear Science and Techniques 2024年第2期35卷 103-109页

作者： jie Zhao Jin-Hui Chen Xu-Guang Huang Yu-gang Ma Key Laboratory of Nuclear Physics and Ion-beam Application(MOE) Institute of Modern PhysicsFudan UniversityShanghai 200433China Shanghai Research Center for Theoretical Nuclear Physics NSFC and Fudan UniversityShanghai 200438China Physics Department and Center for Particle Physics and Field Theory Fudan UniversityShanghai 200438China

Ultra-peripheral heavy-ion collisions(UPCs)offer unique opportunities to study processes under strong electromagnetic fields.In these collisions,highly charged fast-moving ions carry strong electromagnetic fields that can be effectively treated as photon fluxes.The exchange of photons can induce photonuclear and two-photon interactions and excite ions.This excitation of the ions results in Coulomb dissociation with the emission of photons,neutrons,and other particles.Additionally,the electromagnetic fields generated by the ions can be sufficiently strong to enforce mutual interactions between the two colliding ions.Consequently,the two colliding ions experience an electromagnetic force that pushes them in opposite directions,causing a back-to-back correlation in the emitted neutrons.Using a Monte Carlo simulation,we qualitatively demonstrate that the above electromagnetic effect is large enough to be observed in UPCs,which would provide a clear means to study strong electromagnetic fields and their effects.

关键词： Electromagnetic fields Neutrons Ultra-peripheral relativistic heavy-ion collisions(UPC)

Revealing Al-O/Al-F reaction dynamic effects on the combustion of aluminum nanoparticles in oxygen/fluorine containing environments:A reactive molecular dynamics study meshing together experimental validation

在线全文

学校读者我要写书评

暂无评论

Defence Technology（防务技术） 2024年第4期34卷 313-327页

作者： gang Li Chuande Zhao Qian Yu Fang Yang jie Chen Institute of Chemical Materials China Academy of Engineering Physics(CAEP)P.O.Box 919-311Mianyang 621900SichuanChina

Improving the energy conversion efficiency in metallic fuel(e.g.,Al)combustion is always desirable but challenging,which often involves redox reactions of aluminum(Al)with various mixed oxidizing environments.For instance,Al-O reaction is the most common pathway to release limited energy while Al-F reaction has received much attentions to enhance Al combustion efficiency.However,microscopic understanding of the Al-O/Al-F reaction dynamics remains unsolved,which is fundamentally necessary to further improve Al combustion efficiency.In this work,for the first time,Al-O/Al-F reaction dynamic effects on the combustion of aluminum nanoparticles(n-Al)in oxygen/fluorine containing environments have been revealed via reactive molecular dynamics(RMD)simulations meshing together combustion experiments.Three RMD simulation systems of Al core/O_(2)/HF,n-Al/O_(2)/HF,and n-Al/O_(2)/CF4 with oxygen percentage ranging from 0%to 100%have been performed.The n-Al combustion in mixed O_(2)/CF_4 environments have been conducted by constant volume combustion experiments.RMD results show that Al-O reaction exhibits kinetic benefits while Al-F reaction owns thermodynamic benefits for n-Al combustion.In n-Al/O_(2)/HF,Al-O reaction gives faster energy release rate than Al-F reaction(1.1 times).The optimal energy release efficiency can be achieved with suitable oxygen percentage of 10%and 50%for n-Al/O_(2)/HF and n-Al/O_(2)/CF_4,respectively.In combustion experiments,90%of oxygen percentage can optimally enhance the peak pressure,pressurization rate and combustion heat.Importantly,Al-O reaction prefers to occur on the surface regions while Al-F reaction prefers to proceed in the interior regions of n-Al,confirming the kinetic/thermodynamic benefits of Al-O/Al-F reactions.The synergistic effect of Al-O/Al-F reaction for greatly enhancing n-Al combustion efficiency is demonstrated at atomicscale,which is beneficial for optimizing the combustion performance of metallic fuel.

关键词： Al-O/Al—F reaction Kinetic benefits Thermodynamic benefits Molecular dynamics Combustion

Surface demineralized freeze-dried bone allograft followed by reimplantation in a failed mandibular dental implant

同方期刊数据库博看期刊评论

在线全文

学校读者我要写书评

暂无评论

Regenerative Biomaterials 2024年第1期3卷 82-93页

作者： Jing Zhang jie Wang Jiayi you Xuan Qin Huimin Chen Xiantong Hu Yantao Zhao Yang Xia Jiangsu Key Laboratory of Oral Diseases Nanjing Medical UniversityNanjingJiangsu 210029PR China Jiangsu Province Engineering Research Center of Stomatological Translational Medicine Nanjing Medical UniversityNanjingJiangsu 210029PR China Department of Restorative Dental Sciences Faculty of DentistryThe University of Hong KongHong Kong SARPR China Senior Department of Orthopedics The Fourth Medical Center of PLA General HospitalBeijing100048PR China Beijing Engineering Research Center of Orthopedics Implants Beijing 100048PR China State Key Laboratory of Military Stomatology Xi'an 710032PR China

The removal of a failed implant with high torque causes significant damage to the surrounding tissue,compromising bone regeneration and subsequent osseointegration in the defect area.Here,we report a case of carrier screw fracture followed by immediate implant removal,bone grafting and delayed reimplantation.A dental implant with a fractured central carrier screw was removed using the bur-forceps technique.The resulting three-wall bone defect was filled with granular surface demineralized freeze-dried bone allograft(SD-FDBA).Cone-beam computerized tomography was performed at 1week,6months and 15months postoperatively and standardized for quantitative evaluation.The alveolar bone width and height at 15months post-surgery were about 91%of the original values,with a slightly lower bone density,calculated using the gray value ratio.The graft site was reopened and was found to be completely healed with dense and vascularized bone along with some residual bone graft.Reimplantation followed by restoration was performed 8months later.The quality of regenerated bone following SD-FDBA grafting was adequate for osseointegration and longterm implant success.The excellent osteogenic properties of SD-FDBA are attributed to its human origin,cortical bone-like structure,partly demineralized surfaces and bone morphogenetic protein-2-containing nature.Further investigation with more cases and longer follow-up was required to confirm the final clinical effect.

关键词： dental implant implant failure allogeneic bone bone regeneration reimplantation

Synthesis of porous flower-like SnO_(2)/CdSnO_(3) microstructures with excellent sensing performances for volatile organic compounds

在线全文

维普期刊数据库

学校读者我要写书评

暂无评论

Frontiers of Materials Science 2024年第1期18卷 45-57页

作者： jie Wan gang Wang Haibo Ren Jiarui Huang Sang Woo Joo School of Materials Science and Engineering Anhui Polytechnic UniversityWuhu 241000China Key Laboratory of Functional Molecular Solids of the Ministry of Education College of Chemistry and Materials ScienceAnhui Normal UniversityWuhu 241002China School of Mechanical Engineering Yeungnam UniversityGyeongsanGyeoungbuk 712749Republic of Korea

Porous flower-like SnO_(2)/CdSnO_(3) microstructures self-assembled by uniform nanosheets were synthesized using a hydrothermal process followed by calcination,and the sensing performance was measured when a gas sensor,based on such microstructures,was exposed to various volatile organic compound(VOC)gases.The response value was found to reach as high as 100.1 when the SnO_(2)/CdSnO_(3) sensor was used to detect 100 ppm formaldehyde gas,much larger than those of other tested VOC gases,indicating the high gas sensitivity possessed by this sensor especially in the detection of formaldehyde gas.Meanwhile,the response/recovery process was fast with the response time and recovery time of only 13 and 21 s,respectively.The excellent gas sensing performance derive from the advantages of SnO_(2)/CdSnO_(3),such as abundant n-n heterojunctions built at the interface,high available specific surface area,abundant porosity,large pore size,and rich reactive oxygen species,as well as joint effects arising from SnO_(2) and CdSnO_(3),suggesting that such porous flower-like SnO_(2)/CdSnO_(3) microstructures composed of nanosheets have a high potential for developing gas sensors.

关键词： SnO_(2)/CdSnO_(3) porous flower-like microstructure volatile organic gas sensingproperty gas sensor

Clinicopathological characteristics and typing of multilocular cystic renal neoplasm of low malignant potential

在线全文

维普期刊数据库

学校读者我要写书评

暂无评论

World Journal of Clinical Cases 2024年第14期12卷 2332-2341页

作者： Wen-Long Gao gang Li Dong-Sheng Zhu Yuan-jie Niu Department of Urology The Second Hospital of Tianjin Medical UniversityTianjin 300211China Department of Pediatric Surgery The First People’s Hospital of LianyungangLianyungang 222000Jiangsu ProvinceChina

BACKGROUND Up until now,no research has been reported on the association between the cli-nical growth rate of multilocular cystic renal neoplasm of low malignant potential(MCRNLMP)and computed tomography(CT)imaging characteristics.Our study sought to examine the correlation between them,with the objective of distin-guishing unique features of MCRNLMP from renal cysts and exploring effective management strategies.AIM To investigate optimal management strategies of MCRNLMP.METHODS We retrospectively collected and analyzed data from 1520 patients,comprising 1444 with renal cysts and 76 with MCRNLMP,who underwent renal cyst decom-pression,radical nephrectomy,or nephron-sparing surgery for renal cystic disease between January 2013 and December 2021 at our institution.Detection of MC-RNLMP utilized the Bosniak classification for imaging and the 2016 World Health Organization criteria for clinical pathology.RESULTS Our meticulous exploration has revealed compelling findings on the occurrence of MCRNLMP.Precisely,it comprises 1.48%of all cases involving simple renal cysts,5.26%of those with complex renal cysts,and a noteworthy 12.11%of renal tumors coexisting with renal cysts,indicating a statistically significant difference(P=0.001).Moreover,MCRNLMP constituted a significant 22.37%of the patient po-pulation whose cysts demonstrated a rapid growth rate of≥2.0 cm/year,whereas it only represented 0.66%among those with a growth rate below 2.0 cm/year.Of the 76 MCRNLMP cases studied,none of the nine patients who underwent subsequent nephron-sparing surgery or radical nephrectomy following renal cyst decompression experienced recurrence or metastasis.In the remaining 67 patients,who were actively monitored over a 3-year postoperative period,only one showed suspicious recurrence on CT scans.CONCLUSION MCRNLMP can be tentatively identified and categorized into three types based on CT scanning and growth rate indicators.In treating MCRNLMP,partial nephrectomy is preferred,while radical nephrectomy should be minimi-zed.After surg

关键词： Renal cysts Multilocular cystic renal neoplasm of low malignant potential Computed tomography Diagnosis Treatment

Effect of austenitizing condition on mechanical properties,microstructure and precipitation behavior of AISI H13 steel

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 Iron and Steel Research(International) 2024年第1期31卷 143-156页

作者： An-gang Ning Yang Liu Rui Gao Stephen Yue Ming-bo Wang Han-jie Guo College of Materials Science and Engineering Taiyuan University of TechnologyTaiyuan030024ShanxiChina Department of Mining and Materials Engineering McGill UniversityMontrealQCH3A 0C5Canada ASSAB Tooling Technology(Chongqing)Co. Ltd.Chongqing401120China School of Metallurgical and Ecological Engineering University of Science and Technology BeijingBeijing100083China

The effects of austenitizing temperature(1223,1303,and 1373 K)and holding time(1-1500 s)on the microstructure,mechanical properties,and precipitation behavior of the H13 hot work die steel were investigated.The results indicate a softening phenomenon when H13 steel is austenitized at 1303 K beyond 900 s and 1373 K beyond 600 s,respectively.For the sample held for 1200 s,the tensile strength is found capable of reaching up to 2.2 GPa when quenched from a temperature above 1303 K.Meanwhile,prior-austenite grain size increases with the increase in austenitizing temperature.The kinetic behavior of the precipitates(mainly MC-type carbides)in H13 steel could be elaborated through the principles set forth by the Arrhenius and Avrami equations.Finally,the comprehensive strengthening of the H13 steel was discussed in detail.The results show that the activation energy of the transformed fraction of carbides is higher than that of the diffusion process for common alloying elements(Cr,V,Mo,and Ni)found in the austenite.This suggests that it would be difficult for precipitates to dissolve into the matrix when H13 steel is austenitized at high temperatures.With the increasing austenitizing temperature,the precipitation fraction decreases,and the dislocation density increases.The dislocation strengthening is regarded as the dominant strengthening contributed to yield strength in as-quenched H13 steel.

关键词： H13 steel Austenitizing Mechanical property Precipitation behavior Comprehensive strengthening

αDecay in extreme laser fields within a deformed Gamow-like model

在线全文

维普期刊数据库

学校读者我要写书评

暂无评论

Nuclear Science and Techniques 2024年第2期35卷 131-144页

作者： Qiong Xiao Jun-Hao Cheng Yang-Yang Xu you-Tian Zou Jun-gang Deng Tong-Pu Yu Department of Physics National University of Defense TechnologyChangsha 410073China College of Science China Three Gorges UniversityYichang 443002China

In this study, the effect of extreme laser fields on the α decay process of ground-state even–even nuclei was investigated.Using the deformed Gamow-like model, we found that state-of-the-art lasers can cause a slight change in the α decay penetration probability of most nuclei. In addition, we studied the correlation between the rate of change of the α decay penetration probability and angle between the directions of the laser electric field and α particle emission for different nuclei. Based on this correlation, the average effect of extreme laser fields on the half-life of many nuclei with arbitrary α particle emission angles was calculated. The calculations show that the laser suppression and promotion effects on the α decay penetration probability of the nuclei population with completely random α particle-emission directions are not completely canceled.The remainder led to a change in the average penetration probability of the nuclei. Furthermore, the possibility of achieving a higher average rate of change by altering the spatial shape of the laser is explored. We conclude that circularly polarized lasers may be helpful in future experiments to achieve a more significant average rate of change of the α decay half-life of the nuclei population.

关键词： αDecay Deformed Gamow-like model Half-lives Extreme laser field Penetration probability