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Spin Transport in a Magnetic Superlattice with Broken Two-Fold Symmetry

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Chinese Physics Letters 2010年第6期27卷 167-170页

作者： huo qiu-hong WANG Ru-Zhi CHEN Si-Ying XUE Kun YAN Hui Laboratory of Thin Film Materials College of Materials Science and Engineering Beijing University of Technology Beijing 100124 School of Optoelectronics Beijing Institute of Technology Beijing 100081 Australian Research Council Centre of Excellence for Quantum Computer Technology and School of Physics University of New South Wales Sydney New South Wales 2052 Australia

We theoretically investigate the spin-dependent electron transport properties in a magnetic superlattice （MSL） with broken two-fold symmetry. An abnormal barrier in the MSL can break the two-fold symmetry of the system when it is not located at the two-fold symmetry center. A two-fold symmetry breaking factor is introduced to describe the two-fold symmetry breaking degree. Our numerical calculations show that the transmission, the conductance and the spin polarization are non-trivially dependent on the two-fold symmetry breaking factor. When the factor is large enough, the polarization almost approaches 100% in a proper Fermi energy range. However, for two mutually mirror-symmetric MSLs with the same factor, their polarizations may be either similar or distinct. These features provide some clues to the design and applications of MSL-based spin filters or spin-dependent tunneling electron devices.

关键词： ELECTRON transport MAGNETIC materials SUPERLATTICES BROKEN symmetry (Physics) NUMERICAL calculations FERMI surfaces TUNNELING (Physics)

Asymmetric dark matter and Sommerfeld enhancement

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Communications in Theoretical Physics 2024年第8期76卷 118-123页

作者： Sujuan qiu Hoernisa Iminniyaz Wensheng huo School of Physics Science and Technology Xinjiang UniversityUrumqi 830017China

We study the relic density of asymmetric dark matter with long-range interactions by considering the Sommerfeld effect. We find that the annihilation cross section of asymmetric dark matter is enhanced by the Sommerfeld effect and thus the relic density is decreased. Then we use the Planck data to constrain the asymmetry factor, coupling, and to derive the upper bounds on the dark matter mass in s-wave and p-wave annihilation cases.

关键词： asymmetric dark matter relic density Sommerfeld enhancement

Elastic three-dimensional phononic topological insulators with Dirac hierarchy

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Science China(Physics,Mechanics & Astronomy) 2024年第5期67卷 54-62页

作者： Shao-Yong huo qiu-Shuang Yang Jiu-Jiu Chen hong-Kang Li Long-Chao Yao Fu-Chun He Chun-Ming Fu College of Mechanical Engineering University of South ChinaHengyang 421001China State Key Laboratory of Advanced Design and Manufacturing for Vehicle Body College of Mechanical and Vehicle EngineeringHunan UniversityChangsha 410082China

Three-dimensional(3D)phononic topological insulators(TIs)featuring two-dimensional(2D)surface states and one-dimensional(1D)hinge states have opened up a new route for multi-dimensional robust wave transport,providing unprecedented methods for integrated acoustic sensors and energy harvesting ***,aiming at the elastic 3D phononic TI with gapless surface states and hinge states,the realization of elastic 3D phononic TIs with gapless surface states and hinge states is a significant challenge due to the complicated multi-mode polarization of elastic waves in 3D *** this study,we demonstrate an elastic 3D phononic TI with a Dirac hierarchy by elaborately operating the corresponding spatial symmetries of the chiral honeycomb ***,a 3D double Dirac cone of elastic wave can be achieved by doubling the lattice along the outof-plane direction to fold two iso-frequency Weyl *** topological phase transitions and 2D gapless two-fold Dirac surface states of elastic wave are realized by breaking the half-lattice spatial translation ***,based on the Brillouin zone folding along the in-plane direction,the 2D gapless two-fold surface Dirac cones are folded into four-fold surface Dirac ***,by inducing the relative radius of adjacent holes to break the in-plane spatial inversion symmetry,the fourfold surface Dirac cones are gapped and associated with a surface state inversion,in which the gapless 1D hinge Dirac dispersion is *** research offers a route for engineering the hierarchies of TIs in 3D elastic wave systems and provides new possibilities for designing 3D ultrasonic devices with unconventional functions.

关键词： Dirac topological hierarchy

Current collapse suppressed GaN diodes with 38 Watts high RF power rectifier capability

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Science China(Information Sciences) 2024年第2期67卷 335-336页

作者： Kui DANG Zhilin qiu Shudong huo Peng ZHAN Huining LIU Yachao ZHANG Jing NING hong ZHOU Jincheng ZHANG Key Lab of Ministry of Education for Wide Band-Gap Semiconductor Materials and Devices School of MicroelectronicsXidian University Guangzhou Wide Bandgap Semiconductor Innovation Center Guangzhou Institute of TechnologyXidian University

Microwave power transmission(MPT) could realize the point-to-point long-distance transfer of energy without any wires, which makes it attractive for solar-powered satellites,drones, and implantable medical devices, and has aroused enormous attention [1]. Microwave rectifiers could convert RF(radio frequency) energy into DC(direct current) power,

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Diversity and ecological assembly process of aerobic anoxygenic phototrophic bacteria in a low irradiation area,Three Gorges Reservoir

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Journal of Environmental Sciences 2024年第9期143卷 116-125页

作者： Lixin huo Anran Ma hong Liu Xingzu Wang Cheng Song Chongqing Institute of Green and Intelligent Technology Chinese Academy of SciencesChongqing 400714China Chongqing School University of Chinese Academy of SciencesCollege of Resources and EnvironmentChongqing 400714China Key Laboratory of Reservoir Aquatic Environment Chinese Academy of SciencesChongqing 400714China University of Chinese Academy of Sciences Beijing 100049China

Aerobic anoxygenic phototrophic bacteria(AAPB)are significant bacterial groups in aquatic ecosystems,known for their rapid growth and photoheterotrophic ***,the distribution and ecological assembly process of AAPB in low irradiation freshwater basins remain unclear,warranting further *** this study,we present the diversity,abundance,spatial variations,ecological process,and community interaction of AAPB in sediment of Three Gorges Reservoir(TGR)under low *** findings demonstrate the dominant genera of AAPB community that exist in the TGR area also are appeared in different waters,with some regional ***,the concentration of pufM gene,an indicator for AAPB,maintains a consistently high numerical level ranging from(2.21±0.44)×10^(4)to(9.98±0.30)×10^(7)gene copies/*** solar irradiation is suggested as the major factor affecting AAPB,it remains unclear whether and how AAPB differ between regions due to varying solar irradiation *** results show spatial differences between total bacteria and AAPB communities,with significant differences observed only in *** and environmental factor contributed less than 10%to the spatial difference of community,with sediment type and environmental factors being the key factors influencing microbial community *** stochastic process plays a dominant role in the aggregation and replacement of AAPB communities,among which the most contribution is dispersal *** AAPB network,Yoonia and Gemmobacter are the hubs for *** results valuable insights into the AAPB communities in TGR with low irradiation.

关键词： Three Gorges Reservoir(TGR) Aerobic anoxygenic phototrophic bacteria(AAPB) Bacterial community Null model Community assembly

Surface-induced Microstructure and Performance Changes in P3HT Ultrathin Films

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Chinese Journal of Polymer Science 2024年第6期42卷 805-814页

作者： hong-Tao Shan Jia-Xin He Bing-Yan Zhu Xue-Ting Cao Ying-Ying Yan Jian-Jun Zhou hong huo Beijing Key Laboratory of Energy Conversion and Storage Materials College of ChemistryBeijing Normal UniversityBeijing100875China

In this work,poly(3-hexylthiophene)(P3HT)ultrathin films(P3HT-T)were prepared by spin-coating a dilute P3HT solution(in a toluene:o-dichlorobenzene(Tol:ODCB)blend with a volume ratio of 80:20)with ultrasonication and the addition of the nucleating agent bicycle[2.2.1]heptane-2,3-dicarboxylic acid disodium salt(HPN-68L)on glass,Si wafers and indium tin oxide(ITO)*** electrical and mechanical properties of the P3HT-T ultrathin films were investigated,and it was found that the conductivity and crack onset strain(COS)were simultaneously improved in comparison with those of the corresponding pristine P3HT film(P3HT-0,without ultrasonication and nucleating agent)on the same substrate,regardless of what substrate was ***,the conductivity of P3HT-T ultrathin films on different substrates was similar(varying from 3.7 S·cm^(-1)to 4.4 S·cm^(-1)),yet the COS increased from 97%to 138%by varying the substrate from a Si wafer to *** grazing-incidence wide-angle X-ray diffraction(GIXRD),UV-visible(UV-Vis)spectroscopy and atomic force microscopy(AFM),we found that the solid order and crystallinity of the P3HT-T ultrathin film on the Si wafer are highest,followed by those on glass,and much lower on ***,the surface energy and roughness of three substrates were investigated,and it was found that the polar component of the surface energyγp plays a critical role in determining the crystalline microstructures of P3HT ultrathin films on different *** work indicates that the P3HT ultrathin film can obviously improve the stretchability and simultaneously retain similar electrical performance when a suitable substrate is *** findings offer a new direction for research on stretchable CP ultrathin films to facilitate future practical applications.

关键词： P3HT ultrathin film Substrate Crystalline microstructures Polar component of the surface energy Electrical and stretchable performances

More than just aligning the teeth:Clear aligners with multifunctional prowess

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Nano Research 2024年第8期17卷 7665-7674页

作者： Yang Chen Lei-Ming Cao Nian-Nian Zhong Zi-Zhan Li Lin-Lin Bu Fang-Yi huo hong He State Key Laboratory of Oral and Maxillofacial Reconstruction and Regeneration Key Laboratory of Oral Biomedicine Ministry of EducationHubei Key Laboratory of StomatologySchool and Hospital of StomatologyWuhan UniversityWuhan 430079China Department of Oral and Maxillofacial-Head Neck Oncology School and Hospital of StomatologyWuhan UniversityWuhan 430079China Department of Zhuankou Clinical Branches School and Hospital of StomatologyWuhan UniversityWuhan 430000China Department of Orthodontics School and Hospital of StomatologyWuhan UniversityWuhan 430079China

With the increasing demand for beauty and health,clear aligners(CAs)have been widely applied among patients with ***,patients treated with CAs also face some potential complications,such as demineralization,dental caries,and periodontal *** addition,some patients have additional needs to improve their quality of life,such as bleaching *** order to prevent or solve these problems,the modification of CAs is a promising method because their extensive long-term contact with tooth surfaces makes them ideal devices for implementing adjuvant medical *** this review,we discuss various advanced CAs with medical functions based on the clinical needs of *** far as we know,the additional functions of CAs mainly include antibacterial,remineralization,whitening,and accelerating tooth *** functions are achieved by two major pathways,the combination of CAs with drugs/biomaterials and increasing the capacity or affinity of *** addition,we discuss the current limitations of in vitro experiments which are designed to explore the effectiveness and properties of novel CAs,and the challenges of bringing a multifunctional appliance from proposal to clinical *** the end of this review,we provide insights into the broader prospects for the improvement of CAs.

关键词： advanced clear aligners medical device modification drug delivery system personalized medicine

Chiral multiple-resonance thermally activated delayed fluorescence materials based on chiral spiro-axis skeleton for efficient circularly polarized electroluminescence

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Science China Chemistry 2024年第7期67卷 2257-2264页

作者： Shi-Quan Song Xiao Han Zhong-Zhong huo Ching-Fai Yip Xian-Fang hong Meng-Ning Ding You-Xuan Zheng State Key Laboratory of Coordination Chemistry Jiangsu Key Laboratory of Advanced Organic MaterialsSchool of Chemistry and Chemical EngineeringNanjing UniversityNanjing 210023China Key Laboratory of Mesoscopic Chemistry of Ministry of Education School of Chemistry and Chemical EngineeringNanjing UniversityNanjing 210023China

Chiral luminescence materials have potential applications in the field of three-dimensional displays due to their circularly polarized luminescence(CPL)***,the further development of circularly polarized organic light-emitting diodes(CP-OLEDs)needs to meet the requirements of high efficiency,high color purity,low cost,and high dissymmetry factor(gPLor gEL),chiral multiple resonance thermally activated delayed fluorescence(MR-TADF)materials are considered as candidates in these ***,based on a pair of chiral spirofluorene precursors,two pairs of high-performance chiral MR-TADF emitters((R/S)-p-Spiro-DtBuCzB and(R/S)-m-Spiro-DtBuCzB)are developed,which exhibit strong emissions peaking at 491 and 502 nm in toluene with full-width at half-maximum values of 25 and 33 nm,*** addition,small singlet–triplet energy gaps of 0.15 and 0.10 eV with high absolute photoluminescence efficiencies of 95.0%and 96.7%are observed for p-Spiro-DtBuCzB and m-Spiro-DtBuCzB molecules,*** based on p-Spiro-DtBuCzB and m-Spiro-DtBuCzB display high maximum external quantum efficiencies of 29.6%and 33.8%,*** importantly,CP-OLEDs present symmetric circularly polarized electroluminescence spectra with|gEL|factors of 3.36×10^(-4)and 7.66×10^(-4)for devices based on(R/S)-p-Spiro-DtBuCzB and(R/S)-m-Spiro-DtBuCzB enantiomers,respectively.

关键词： chiral spiro-axis skeleton-based material multiple resonance thermally activated delayed fluorescence circularly polarized electroluminescence dissymmetry factor external quantum efficiency

具有非阿贝尔Chern-Simons拓扑项的SU(n)N=2超对称规范场系统的量子化和分数自旋(英文)

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原子核物理评论 2007年第4期24卷 274-279页

作者：霍秋红黄永畅北京工业大学理论物理研究所北京100022

基于路径积分的Faddeev-Senjanovic量子化,先将具有非阿贝尔Chern-Simons拓扑项的SU(n)N=2超对称规范场系统量子化,然后利用整体正则Noether定理得到了系统的总角动量,在量子水平下导出了该系统的分数自旋性质,并发现其分数自旋有来自... 详细信息

基于路径积分的Faddeev-Senjanovic量子化,先将具有非阿贝尔Chern-Simons拓扑项的SU(n)N=2超对称规范场系统量子化,然后利用整体正则Noether定理得到了系统的总角动量,在量子水平下导出了该系统的分数自旋性质,并发现其分数自旋有来自非阿贝尔规范群分量的贡献。

关键词：超对称 Chem—Simons 约束系统分数自旋规范场