One important issue in current condensed matter physics is the search of quantum spin liquid(QSL),an exotic magnetic state with strongly-fluctuating and highly-entangled spins down to zero temperature without static o...One important issue in current condensed matter physics is the search of quantum spin liquid(QSL),an exotic magnetic state with strongly-fluctuating and highly-entangled spins down to zero temperature without static order.However,there is no consensus on the existence of a QSL state in any real material so far,due to inevitable disorder and intricate competing exchange interactions on frustrated spin lattices.Here we report systematic heat transport measurements on a honeycomb-lattice compound BaCo_(2)(AsO_(4))_(2),which manifests magnetic order in zero field.In a narrow in-plane field range after the magnetic order is nearly suppressed,in both perpendicular and parallel to the zigzag direction,a finite residual linear term of thermal conductivity is clearly observed,which is attributed to mobile fermionic excitations.In addition,the spin-phonon scattering rate exhibits a T-linear behavior when the order disappears.These observations suggest a partial QSL state with gapless spinon excitations in BaCo_(2)(AsO_(4))_(2),that emerges when a portion of the spins remains ordered,and vanishes as the spins become progressively polarized.展开更多
Accurate genomic information is essential for advancing genetic breeding research in specific rice varieties.This study presented a gapless genome assembly of the indica rice cultivar Zhonghui 8015(ZH8015)using Pac Bi...Accurate genomic information is essential for advancing genetic breeding research in specific rice varieties.This study presented a gapless genome assembly of the indica rice cultivar Zhonghui 8015(ZH8015)using Pac Bio HiFi,Hi-C,and ONT(Oxford Nanopore Technologies)ultra-long sequencing technologies,annotating 43037 gene structures.Subsequently,utilizing this genome along with transcriptomic and metabolomic techniques,we explored ZH8015's response to brown planthopper(BPH)infestation.Continuous transcriptomic sampling indicated significant changes in gene expression levels around 48 h after BPH feeding.Enrichment analysis revealed particularly significant alterations in genes related to reactive oxygen species scavenging and cell wall formation.Metabolomic results demonstrated marked increases in levels of several monosaccharides,which are components of the cell wall and dramatic changes in flavonoid contents.Omics association analysis identified differentially expressed genes associated with key metabolites,shedding light on ZH8015's response to BPH infestation.In summary,this study constructed a reliable genome sequence resource for ZH8015,and the preliminary multi-omics results will guide future insect-resistant breeding research.展开更多
Using Green＇s function method, we investigate the spin transport properties of armchair graphene nanoribbons （AG- NRs） under magnetic field and uniaxial strain. Our results show that it is very difficult to transfo...Using Green＇s function method, we investigate the spin transport properties of armchair graphene nanoribbons （AG- NRs） under magnetic field and uniaxial strain. Our results show that it is very difficult to transform narrow AGNRs directly from semiconductor to spin gapless semiconductors （SGS） by applying magnetic fields. However, as a uniaxial strain is exerted on the nanoribbons, the AGNRs can transform to SGS by a small magnetic field. The combination mode be- tween magnetic field and uniaxial strain displays a nonmonotonic arch-pattern relationship. In addition, we find that the combination mode is associated with the widths of nanoribbons, which exhibits group behaviors.展开更多
We study the effect of electron-phonon （e-ph） interaction on the elastic and inelastic electronic transport of a nanowire connected to two simple rigid leads within the tight-binding and harmonic approximations. The...We study the effect of electron-phonon （e-ph） interaction on the elastic and inelastic electronic transport of a nanowire connected to two simple rigid leads within the tight-binding and harmonic approximations. The model is constructed using Green＇s function and multi-channel techniques, taking into account the local and nonlocal e-ph interactions. Then, we examine the model for the gapless （simple chain） and gapped （PA-like nanowire） systems. The results show that the tunneling conductance is improved by the e-ph interaction in both local and nonlocal regimes, while for the resonance conductance, the coherent part mainly decreases and the incoherent part increases. At the corresponding energies which depend on the phonon frequency, two dips in the elastic and two peaks in the inelastic conductance spectra appear. The reason is the absorption of the phonon by the electron in transition into inelastic channels.展开更多
The ultimate goal of genome assembly is a high-accuracy gapless genome.Here,we report a new assembly pipeline that is used to produce a gapless genome for the indica rice cultivar Minghui 63.The resulting 397.71-Mb fi...The ultimate goal of genome assembly is a high-accuracy gapless genome.Here,we report a new assembly pipeline that is used to produce a gapless genome for the indica rice cultivar Minghui 63.The resulting 397.71-Mb final assembly is composed of 12 contigs with a contig N50 size of 31.93 Mb.Each chromosome is represented by a single contig and the genomic sequences of all chromosomes are gapless.Quality evaluation of this gapless genome assembly showed that gene regions in our assembly have the highest completeness compared with the other 15 reported high-quality rice genomes.Further comparison with the japonica rice genome revealed that the gapless indica genome assembly contains more transposable elements(TEs)and segmental duplications(SDs),the latter of which produce many duplicated genes that can affect agronomic traits through dose effect or sub-/neo-functionalization.The insertion of TEs can also affect the expression of duplicated genes,which may drive the evolution of these genes.Furthermore,we found the expansion of nucleotide-binding site with leucine-rich repeat disease-resistance genes and cis-zeatin-O-glucosyltransferase growth-related genes in SDs in the gapless indica genome assembly,suggesting that SDs contribute to the adaptive evolution of rice disease resistance and developmental processes.Collectively,our findings suggest that active TEs and SDs synergistically contribute to rice genome evolution.展开更多
Layered van der Waals(vdW) topological materials, especially the recently discovered MnBi_(2)Te_(4)-family magnetic topological insulators(TIs), have aroused great attention. However, there has been a serious debate a...Layered van der Waals(vdW) topological materials, especially the recently discovered MnBi_(2)Te_(4)-family magnetic topological insulators(TIs), have aroused great attention. However, there has been a serious debate about whether the surface states are gapped or gapless for antiferromagnetic(AFM) TI MnBi_(2)Te_(4), which is crucial to the prospect of various magnetic topological phenomena. Here, a minimal three-Dirac-fermion approach is developed to generally describe topological surface states of nonmagnetic/magnetic vdW TIs under the modulation of the interlayer vdW gap. In particular, this approach is applied to address the controversial issues concerning the surface states of vdW AFM TIs. Remarkably, topologically protected gapless Dirac-cone surface states are found to arise due to a small expansion of the interlayer vdW gap on the surface, when the Chern number equals zero for the surface ferromagnetic layer;while the surface states remain gapped in all other cases. These results are further confirmed by our first-principles calculations on AFM TI MnBi_(2)Te_(4). The theorectically discovered gapless Dirac-cone states provide a unique mechanism for understanding the puzzle of the experimentally observed gapless surface states in MnBi_(2)Te_(4).This work also provides a promising way for experiments to realize the intrinsic magnetic quantum anomalous Hall efect in MnBi_(2)Te_(4) films with a large energy gap.展开更多
Subject Code:A04Frustrated quantum magnets have developed into one of the hottest topics in condensed matter physics because of the wide range of novel physical phenomena they exhibit,which includes quantum spin-liqui...Subject Code:A04Frustrated quantum magnets have developed into one of the hottest topics in condensed matter physics because of the wide range of novel physical phenomena they exhibit,which includes quantum spin-liquid states,fractionalized spin degrees of freedom,and exotic topological properties.This trend is展开更多
Topological band theory has been studied for free fermions for decades,and one of the most profound physical results is the bulk-boundary correspondence.Recently a focus in topological physics is extending topological...Topological band theory has been studied for free fermions for decades,and one of the most profound physical results is the bulk-boundary correspondence.Recently a focus in topological physics is extending topological classification to mixed states.Here,we focus on Gaussian mixed states for which the modular Hamiltonians of the density matrix are quadratic free fermion models with U(1)symmetry and can be classified by topological invariants.The bulk-boundary correspondence is then manifested as stable gapless modes of the modular Hamiltonian and degenerate spectrum of the density matrix.In this article,we show that these gapless modes can be detected by the full counting statistics,mathematically described by a function introduced as F(θ).A divergent derivative atθ=πcan be used to probe the gapless modes in the modular Hamiltonian.Based on this,a topological indicator,whose quantization to unity senses topologically nontrivial mixed states,is introduced.We present the physical intuition of these results and also demonstrate these results with concrete models in both one-and two-dimensions.Our results pave the way for revealing the physical significance of topology in mixed states.展开更多
针对多起750 kV站用无间隙金属氧化物避雷器因内部均压电容管松动或脱落引发的事故,在实验室构建了8种对应缺陷工况,系统研究了高频电流法(high-frequency current transformer,HFCT)、特高频法(ultra-high frequency,UHF)、超声波法及...针对多起750 kV站用无间隙金属氧化物避雷器因内部均压电容管松动或脱落引发的事故,在实验室构建了8种对应缺陷工况,系统研究了高频电流法(high-frequency current transformer,HFCT)、特高频法(ultra-high frequency,UHF)、超声波法及示波器法4种便携式局部放电的测量方法。通过开展无外部干扰、2架梯子干扰、1架梯子干扰及不同干扰距离下的抗干扰能力试验,并与常规阻性电流测试结果进行对比,最终筛选出适用于该类缺陷的现场检测方法,补充了避雷器现场有效局部放电测量手段。试验结果表明,HFCT法更适配现场复杂环境下的应用,UHF法则更适合实验室环境使用。展开更多
基金funded by the National Natural Science Foundations of China(Grant Nos.12034004 and 12174064)the Shanghai Municipal Science and Technology Major Project(Grant No.2019SHZDZX01)+2 种基金the Innovation Program for Quantum Science and Technology(Grant No.2024ZD0300104)supported by U.S.DOE BES DE-SC0012311the Robert A.Welch Foundation under Grant No.C-1839,respectively(P.D.)。
文摘One important issue in current condensed matter physics is the search of quantum spin liquid(QSL),an exotic magnetic state with strongly-fluctuating and highly-entangled spins down to zero temperature without static order.However,there is no consensus on the existence of a QSL state in any real material so far,due to inevitable disorder and intricate competing exchange interactions on frustrated spin lattices.Here we report systematic heat transport measurements on a honeycomb-lattice compound BaCo_(2)(AsO_(4))_(2),which manifests magnetic order in zero field.In a narrow in-plane field range after the magnetic order is nearly suppressed,in both perpendicular and parallel to the zigzag direction,a finite residual linear term of thermal conductivity is clearly observed,which is attributed to mobile fermionic excitations.In addition,the spin-phonon scattering rate exhibits a T-linear behavior when the order disappears.These observations suggest a partial QSL state with gapless spinon excitations in BaCo_(2)(AsO_(4))_(2),that emerges when a portion of the spins remains ordered,and vanishes as the spins become progressively polarized.
基金supported by the Chinese Academy of Agricultural Sciences Innovation Project(Grant No.CAASASTIP-2013CNRRI)Fundamental Research Funds for Central Public Welfare Research Institutes of Chinese Rice Research Institute(Grant No.CPSIBRF-CNRRI-202102)。
文摘Accurate genomic information is essential for advancing genetic breeding research in specific rice varieties.This study presented a gapless genome assembly of the indica rice cultivar Zhonghui 8015(ZH8015)using Pac Bio HiFi,Hi-C,and ONT(Oxford Nanopore Technologies)ultra-long sequencing technologies,annotating 43037 gene structures.Subsequently,utilizing this genome along with transcriptomic and metabolomic techniques,we explored ZH8015's response to brown planthopper(BPH)infestation.Continuous transcriptomic sampling indicated significant changes in gene expression levels around 48 h after BPH feeding.Enrichment analysis revealed particularly significant alterations in genes related to reactive oxygen species scavenging and cell wall formation.Metabolomic results demonstrated marked increases in levels of several monosaccharides,which are components of the cell wall and dramatic changes in flavonoid contents.Omics association analysis identified differentially expressed genes associated with key metabolites,shedding light on ZH8015's response to BPH infestation.In summary,this study constructed a reliable genome sequence resource for ZH8015,and the preliminary multi-omics results will guide future insect-resistant breeding research.
基金supported by the National Basic Research Program of China(Grant No.2012CB921303)the National Natural Science Foundation of China(Grant Nos.51172191,11074211,11074213,51006086,and 51176161)the Joint Funds of the Natural Science Foundation of Hunan Province,China(Grant No.10JJ9001)
文摘Using Green＇s function method, we investigate the spin transport properties of armchair graphene nanoribbons （AG- NRs） under magnetic field and uniaxial strain. Our results show that it is very difficult to transform narrow AGNRs directly from semiconductor to spin gapless semiconductors （SGS） by applying magnetic fields. However, as a uniaxial strain is exerted on the nanoribbons, the AGNRs can transform to SGS by a small magnetic field. The combination mode be- tween magnetic field and uniaxial strain displays a nonmonotonic arch-pattern relationship. In addition, we find that the combination mode is associated with the widths of nanoribbons, which exhibits group behaviors.
基金Project supported by the Iranian Nanotechnology Initiativesupported by Shahrekord University through a research fund
文摘We study the effect of electron-phonon （e-ph） interaction on the elastic and inelastic electronic transport of a nanowire connected to two simple rigid leads within the tight-binding and harmonic approximations. The model is constructed using Green＇s function and multi-channel techniques, taking into account the local and nonlocal e-ph interactions. Then, we examine the model for the gapless （simple chain） and gapped （PA-like nanowire） systems. The results show that the tunneling conductance is improved by the e-ph interaction in both local and nonlocal regimes, while for the resonance conductance, the coherent part mainly decreases and the incoherent part increases. At the corresponding energies which depend on the phonon frequency, two dips in the elastic and two peaks in the inelastic conductance spectra appear. The reason is the absorption of the phonon by the electron in transition into inelastic channels.
基金This study was supported by the National Natural Science Foundation of China(NSFC,nos.31770331 and 31970318)Guangdong Basic and Applied Basic Research Foundation(no.2020B1515120023).
文摘The ultimate goal of genome assembly is a high-accuracy gapless genome.Here,we report a new assembly pipeline that is used to produce a gapless genome for the indica rice cultivar Minghui 63.The resulting 397.71-Mb final assembly is composed of 12 contigs with a contig N50 size of 31.93 Mb.Each chromosome is represented by a single contig and the genomic sequences of all chromosomes are gapless.Quality evaluation of this gapless genome assembly showed that gene regions in our assembly have the highest completeness compared with the other 15 reported high-quality rice genomes.Further comparison with the japonica rice genome revealed that the gapless indica genome assembly contains more transposable elements(TEs)and segmental duplications(SDs),the latter of which produce many duplicated genes that can affect agronomic traits through dose effect or sub-/neo-functionalization.The insertion of TEs can also affect the expression of duplicated genes,which may drive the evolution of these genes.Furthermore,we found the expansion of nucleotide-binding site with leucine-rich repeat disease-resistance genes and cis-zeatin-O-glucosyltransferase growth-related genes in SDs in the gapless indica genome assembly,suggesting that SDs contribute to the adaptive evolution of rice disease resistance and developmental processes.Collectively,our findings suggest that active TEs and SDs synergistically contribute to rice genome evolution.
基金supported by the National Key Projects for Research and Development of China (Grant Nos. 2021YFA1400400, 2017YFA0303203, and 2022YFA1403602)the Fundamental Research Funds for the Central Universities (Grant No. 020414380185)+3 种基金the Natural Science Foundation of Jiangsu Province (Grant No. BK20200007)the National Natural Science Foundation of China (Grant Nos. 12074181, 12104217, 11834006, and 12174182)the Fok Ying-Tong Education Foundation of China (Grant No. 161006)supported by the program A/B for Outstanding PhD candidate of Nanjing University。
文摘Layered van der Waals(vdW) topological materials, especially the recently discovered MnBi_(2)Te_(4)-family magnetic topological insulators(TIs), have aroused great attention. However, there has been a serious debate about whether the surface states are gapped or gapless for antiferromagnetic(AFM) TI MnBi_(2)Te_(4), which is crucial to the prospect of various magnetic topological phenomena. Here, a minimal three-Dirac-fermion approach is developed to generally describe topological surface states of nonmagnetic/magnetic vdW TIs under the modulation of the interlayer vdW gap. In particular, this approach is applied to address the controversial issues concerning the surface states of vdW AFM TIs. Remarkably, topologically protected gapless Dirac-cone surface states are found to arise due to a small expansion of the interlayer vdW gap on the surface, when the Chern number equals zero for the surface ferromagnetic layer;while the surface states remain gapped in all other cases. These results are further confirmed by our first-principles calculations on AFM TI MnBi_(2)Te_(4). The theorectically discovered gapless Dirac-cone states provide a unique mechanism for understanding the puzzle of the experimentally observed gapless surface states in MnBi_(2)Te_(4).This work also provides a promising way for experiments to realize the intrinsic magnetic quantum anomalous Hall efect in MnBi_(2)Te_(4) films with a large energy gap.
文摘Subject Code:A04Frustrated quantum magnets have developed into one of the hottest topics in condensed matter physics because of the wide range of novel physical phenomena they exhibit,which includes quantum spin-liquid states,fractionalized spin degrees of freedom,and exotic topological properties.This trend is
基金supported by the National Key R&D Program of China(Grant No.2023YFA1406702)the Innovation Program for Quantum Science and Technology 2021ZD0302005+1 种基金the XPLORER Prizepartly supported by the Start-up Research Fund of Southeast University(RF1028624190)。
文摘Topological band theory has been studied for free fermions for decades,and one of the most profound physical results is the bulk-boundary correspondence.Recently a focus in topological physics is extending topological classification to mixed states.Here,we focus on Gaussian mixed states for which the modular Hamiltonians of the density matrix are quadratic free fermion models with U(1)symmetry and can be classified by topological invariants.The bulk-boundary correspondence is then manifested as stable gapless modes of the modular Hamiltonian and degenerate spectrum of the density matrix.In this article,we show that these gapless modes can be detected by the full counting statistics,mathematically described by a function introduced as F(θ).A divergent derivative atθ=πcan be used to probe the gapless modes in the modular Hamiltonian.Based on this,a topological indicator,whose quantization to unity senses topologically nontrivial mixed states,is introduced.We present the physical intuition of these results and also demonstrate these results with concrete models in both one-and two-dimensions.Our results pave the way for revealing the physical significance of topology in mixed states.
文摘针对多起750 kV站用无间隙金属氧化物避雷器因内部均压电容管松动或脱落引发的事故,在实验室构建了8种对应缺陷工况,系统研究了高频电流法(high-frequency current transformer,HFCT)、特高频法(ultra-high frequency,UHF)、超声波法及示波器法4种便携式局部放电的测量方法。通过开展无外部干扰、2架梯子干扰、1架梯子干扰及不同干扰距离下的抗干扰能力试验,并与常规阻性电流测试结果进行对比,最终筛选出适用于该类缺陷的现场检测方法,补充了避雷器现场有效局部放电测量手段。试验结果表明,HFCT法更适配现场复杂环境下的应用,UHF法则更适合实验室环境使用。
