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Detecting bulk and edge exceptional points in non-Hermitian systems through generalized Petermann factors

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Frontiers of physics 2024年第2期19卷 169-177页

作者： Yue-Yu zou Yao Zhou Li-mei Chen Peng Ye School of Physics State Key Laboratory of Optoelectronic Materials and Technologiesand Guangdong Provincial Key Laboratory of Magnetoelectric Physics and DevicesSun Yat-sen UniversityGuangzhou 510275China

Non-orthogonality in non-Hermitian quantum systems gives rise to tremendous exotic quantum phenomena,which can be fundamentally traced back to non-unitarity.In this paper,we introduce an interesting quantity(denoted asη)as a new variant of the Petermann factor to directly and efficiently measure non-unitarity and the associated non-Hermitian physics.By tuning the model parameters of underlying non-Hermitian systems,we find that the discontinuity of bothηand its first-order derivative(denoted as■η)pronouncedly captures rich physics that is fundamentally caused by non-unitarity.More concretely,in the 1D non-Hermitian topological systems,two mutually orthogonal edge states that are respectively localized on two boundaries become non-orthogonal in the vicinity of discontinuity ofηas a function of the model parameter,which is dubbed"edge state transition".Through theoretical analysis,we identify that the appearance of edge state transition indicates the existence of exceptional points(EPs)in topological edge states.Regarding the discontinuity of■η,we investigate a two-level non-Hermitian model and establish a connection between the points of discontinuity of■ηand EPs of bulk states.By studying this connection in more general lattice models,we find that some models have discontinuity of■η,implying the existence of EPs in bulk states.

关键词： non-Hermitian Su−Schrieffer−Heeger(SSH)model exceptional point

Structural disruption of melanin-like polymers with boosted UV protection

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Science China Chemistry 2024年第5期67卷 1653-1663页

作者： zhen Yang Xianheng Wang Wanjie Bai Zikun zou Haoxing Wu Yiwen Li Department of Radiology Huaxi MR Research CenterFunctional and Molecular Imaging Key Laboratory of Sichuan ProvinceNational Clinical Research Center for GeriatricsWest China HospitalSichuan UniversityChengdu 610041China College of Polymer Science and Engineering State Key Laboratory of Polymer Materials EngineeringSichuan UniversityChengdu 610065China

Manipulating the energy structure of materials represents an efficient way to regulate their light absorption behaviors. For example, constructing donor-acceptor(D-A) structures to increase the polarizability and reduce the energy bandgap of local molecules has been widely used in the field of organic photovoltaics with ordered structures. Remarkably, even in disordered and chaotic systems such as melanin-like polydopamine(PDA), visible and near-infrared light absorption can be significantly improved using this strategy. However, there has been a noticeable dearth of research on the ultraviolet(UV) light absorption regulation of bioinspired polymers with disordered and chaotic architectures by tailoring the D-A microstructures. In this study, a series of benzoheterocyclic molecules with strong electron-donating features screened by molecular simulation calculations were involved in disrupting the D-A structures within PDA. The destruction of D-A structures promoted the increase of the energy band gap and finally boosted the UV absorption of PDA. The resulting PDA nanoparticles with enhanced UV absorption were further employed to fabricate UV shielding composite films to protect the growth of plants from harmful UV radiation. This research may open up new avenues for structural disruption of bioinspired polymers for enhanced photoprotection applications.

关键词： melanin-like polymers polydopamine D-A structure UV absorption photoprotection

Time evolutions of scalar field perturbation in Schwarzschild de-Sitter black hole from Einstein-scalar–Gauss–Bonnet theory

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Communications in Theoretical Physics 2024年第1期76卷 76-81页

作者： Cheng Xu zhen-Hao Yang Xiao-mei Kuang Rui-Hong Yue Center for Gravitation and Cosmology College of Physical Science and TechnologyYangzhou UniversityYangzhou225009China

The scalar-free black hole could be unstable against the scalar field perturbation when it is coupled to a Gauss–Bonnet(GB)invariant in a special form.It is known that the tachyonic instability in this scenario is triggered by the sufficiently strong GB coupling.In this paper,we focus on the time domain analysis of massive scalar field perturbation around the Schwarzschild de-Sitter black hole in Einstein-scalar–Gauss–Bonnet gravity.By analyzing the scalar field propagation,we find that the scalar field will finally grow when the GB coupling is large enough.This could lead to the instability of the background black hole.Furthermore,we demonstrate how the mass of the scalar field and the GB coupling strength affect the onset of tachyonic instability.

关键词： black hole perturbation scalar-Einstein-Gauss-Bonnet gravity time domain evolution me

Source apportionment of PM_(2.5)using PMF combined online bulk and single-particle measurements:Contribution of fireworks and biomass burning

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Journal of Environmental Sciences 2024年第2期136卷 325-336页

作者： Yanjing Zhang Wenshuai Li Lei Li mei Li zhen Zhou Jianzhen Yu Yang Zhou Frontier Science Center for Deep Ocean Multispheres and Earth System(FDOMES)and Physical Oceanography Laboratory Ocean University of ChinaQingdaoShandong 266100China College of Oceanic and Atmospheric Sciences Ocean University of ChinaQingdaoShandong 266100China Institute of Atmospheric Environment Safety and Pollution Control Jinan UniversityGuangdong 510632China Institute of Environment Hong Kong University of Science and TechnologyClear Water BayKowloonHong KongChina Department of Chemistry Hong Kong University of Science and TechnologyClear Water BayKowloonHong KongChina Division of Environment The Hong Kong University of Science and TechnologyClear Water BayKowloonHong KongChina

Fireworks(FW)could significantly worsen air quality in short term during celebrations.Due to similar tracers with biomass burning(BB),the fast and precise qualification of FW and BB is still challenging.In this study,online bulk and single-particle measurements were combined to investigate the contributions of FW and BB to the overall mass concentrations of PM_(2.5)and specific chemical species by positive matrix factorization(PMF)during the Chinese New Year in Hong Kong in February 2013.With combined information,fresh/aged FW(abundant ^(140)K_(2)NO_(3)^(+)and ^(213)K_(3)SO_(4)^(+)formed from ^(113)K_(2)Cl^(+)discharged by fresh FW)can be extracted from the fresh/aged BB sources,in addition to the Second Aerosol,Vehicles+Road Dust,and Sea Salt factors.The contributions of FW and BB were investigated during three high particle matter episodes influenced by the pollution transported from the Pearl River Delta region.The fresh BB/FW contributed 39.2%and 19.6%to PM_(2.5)during the Lunar Chinese New Year case.However,the contributions of aged FW/BB enhanced in the last two episodes due to the aging process,evidenced by high contributions from secondary aerosols.Generally,the fresh BB/FW showed more significant contributions to nitrate(35.1%and15.0%,respectively)compared with sulfate(25.1%and 5.9%,respectively)and OC(14.8%and11.1%,respectively)on average.In comparison,the aged FW contributed more to sulfate(13.4%).Overall,combining online bulk and single-particle measurement data can combine both instruments’advantages and provide a new perspective for applying source apportionment of aerosols using PMF.

关键词： Source apportionment PMF Online bulk measurements Single particle analysis Fireworks Biomass burning

The P5-saturation Game

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Acta Mathematicae Applicatae Sinica 2024年

作者： zhen HE mei LU School of Mathematics and Statistics Beijing Jiaotong University Department of Mathematical Sciences Tsinghua University

Let F,G and H be three graphs with G ■ H.We call G an F-saturated graph relative to H,if there is no copy of F in G but there is a copy of F in G+e for any e ∈ E（H）\ E（G）.The F-saturation game on host graph H consists of two players,named Max and Min,who alternately add edges of H to G such that each chosen edge avoids creating a copy of F in G,and the players continue to choose edges until G becomes F-saturated relative to H.Max wishes to maximize the length of the game,while Min wishes to minimize the process.Let satg（F,H）(resp.satg'（F,H）) denote the number of edges chosen when Max（resp.when Min） starts the game and both players play optimally.In this article,we show that satg（P5,K_n）=satg'（P5,K_n）=n+2 for n≥ 15,and satg(P5,Km,n),satg'(P5,Km,n) lie in {m+n-[m+2/4」,m+n-[m-3/4]} if n≥5/2 m and m≥ 4,respectively.

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Surface decoration of mesocarbon microbeads with multifunctional TiNbO4-x@C coating layer as high rate and stable anode of Li-ion batteries

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Rare Metals 2024年第5期43卷 2053-2066页

作者： Jia-mei Lai Zhi-Min zou Yu Bai Yu-Tao Xing Chun-Hai Jiang Fujian Provincial Key Laboratory of Functional Materials and Applications Institute of Advanced Energy Materials School of Materials Science and Engineering Xiamen University of Technology Shanghai XFH Science and Technology Development Co. Ltd. Fujian XFH New Energy Materials Co. Ltd. Shenzhen XFH Science and Technology Co. Ltd. Laboratório de Microscopia Eletr?nica de Alta Resolu??o Centro de Caracteriza??o Avan?ada Para a Indústria de Petróleo (LaMAR/CAIPE) Universidade Federal Fluminense

Surface modification of graphite anode with electroactive matters has been proven of a more practical strategy in enhancing the performance of Li-ion batteries than exploring alternative novel anode materials.Herein,rutile Ti NbO4-xnanoparticles with a tunnel structure are employed as multifunctional decoration substances in combination with a carbon coating layer to improve the rate and cycle properties of mesocarbon microbeads（MCMBs）.As compared to pristine MCMB,the Li+diffusion coefficients of the composite anodes are enhanced due to the synergistic effect of Ti Nb O4-x@C.Meanwhile,the overcharge and voltage polarization of the composite anodes at high rate are obviously minimized due to the current sharing effect of the high-potential TiN-bO4-x.Moreover,the amorphous LiyTi Nb O4-xconverted from Ti NbO4-xin the initial lithiation process can deliver pseudocapacitive capacity to the composite anodes from the second cycle.All of these functions of Ti NbO4-x@C coating layer have directly contributed to the improved rate and cycle performance of the MCMB/TiNbO4-x@C composite anodes.The one containing 12.0 wt%Ti NbO4-xexhibits a high reversible specific capacity of 118 m Ah·g-1at 10C (1C=372 m A·g-1),together with a high capacity retention of 90.9%after 300 cycles at 3C,which are all much superior to those of pristine MCMB.

关键词： Li-ion batteries MCMB TiNbO 4− x Surface decoration Rate capability

S-(1,3-Dioxoisoindolin-2-yl)O,O-diethyl phosphorothioate (SDDP): A practical electrophilic reagent for the phosphorothiolation of electron-rich compounds

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Chinese Chemical Letters 2024年第5期35卷 151-154页

作者： Ze-Yuan Ma mei Xiao Cheng-Kun Li Adedamola Shoberu Jian-Ping zou Key Laboratory of Organic Synthesis of Jiangsu Province College of Chemistry and Chemical EngineeringSoochow UniversitySuzhou 215123China

An efficient synthesis of the electrophilic reagent,S-(1,3-dioxoisoindolin-2-yl)O,O-diethyl phosphorothioate(SDDP)is described.Moreover,the synthetic applications of SDDP wherein the transfer of the SP(O)(OEt)_(2) moiety occurs were investigated.In this manner,SDDP underwent facile SP(O)(OEt)_(2) transfer with electron-rich substrates such as ketones,indoles,and thiols to formα-phosphorothiolated ketones,3-phosphorothiolated indoles and S-phosphorothiolated thioethers,respectively.

关键词： Electrophilic reagent Phosphorothiolation Electrophilic substitution

Spatial transcriptomics reveals that metabolic characteristics define the tumor immunosuppression microenvironment via iCAF transformation in oral squamous cell carcinoma

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International Journal of Oral Science 2024年第1期16卷 110-121页

作者： Zheqi Liu zhen Zhang Yu Zhang Wenkai Zhou Xu Zhang Canbang Peng Tong Ji Xin zou Zhiyuan Zhang zhenhu Ren Department of Oral and Maxillofacial-Head and Neck Oncology Shanghai Ninth People’s HospitalShanghai Jiao Tong University School of MedicineCollege of StomatologyShanghai Jiao Tong UniversityNational Center for StomatologyNational Clinical Research Center for Oral DiseasesShanghai Key Laboratory of Stomatology&Shanghai Research Institute of StomatologyShanghaiChina Department of Oral and Maxillofacial Surgery Zhongshan HospitalFudan UniversityShanghaiChina School and Hospital of Stomatology Kunming Medical UniversityKunmingChina Center for Tumor Diagnosis&Therapy Jinshan HospitalFudan UniversityShanghaiChina Department of Pathology Jinshan HospitalFudan UniversityShanghaiChina Hainan Western Central Hospital Academician Zhang Zhiyuan Team Innovation CenterDanzhouChina

Tumor progression is closely related to tumor tissue metabolism and reshaping of the microenvironment. Oral squamous cell carcinoma (OSCC), a representative hypoxic tumor, has a heterogeneous internal metabolic environment. To clarify the relationship between different metabolic regions and the tumor immune microenvironment (TME) in OSCC, Single cell (SC) and spatial transcriptomics (ST) sequencing of OSCC tissues were performed. The proportion of TME in the ST data was obtained through SPOTlight deconvolution using SC and GSE103322 data. The metabolic activity of each spot was calculated using scMetabolism,and k-means clustering was used to classify all spots into hyper-, normal-, or hypometabolic regions. CD4T cell infiltration and TGF-βexpression is higher in the hypermetabolic regions than in the others. Through CellPhoneDB and NicheNet cell-cell communication analysis, it was found that in the hypermetabolic region, fibroblasts can utilize the lactate produced by glycolysis of epithelial cells to transform into inflammatory cancer-associated fibroblasts (iCAFs), and the increased expression of HIF1A in iCAFs promotes the transcriptional expression of CXCL12. The secretion of CXCL12 recruits regulatory T cells (Tregs), leading to Treg infiltration and increased TGF-β secretion in the microenvironment and promotes the formation of a tumor immunosuppressive microenvironment. This study delineates the coordinate work axis of epithelial cells-iCAFs-Tregs in OSCC using SC, ST and TCGA bulk data, and highlights potential targets for therapy.

关键词： CXCL12 microenvironment squamous

Manipulating the Phase Transition Behavior of Dual Temperature-Responsive Block Copolymers by Adjusting Composition and Sequence

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Chinese Journal of Polymer Science 2024年第2期42卷 176-187,I0006页

作者： Zhi zou Xiang Xu Hai-Tao Zhao Jian-Nan Cheng Wei-Wei He Li-Fen Zhang zhen-Ping Cheng Suzhou key Laboratory of Macromolecular Design and Precision Synthesis Jiangsu Key Laboratory of Advanced Functional Polymer Design and ApplicationState and Local Joint Engineering Laboratory for Novel Functional Polymeric MaterialsCollege of ChemistryChemical Engineering and Materials ScienceSoochow UniversitySuzhou215123China State Key Laboratory of Radiation Medicine and Protection School for Radiological and Interdisciplinary Sciences(RAD-X)and Collaborative Innovation Center of Radiation Medicine of JiangsuSoochow UniversitySuzhou215123China

Temperature-responsive polymers have garnered significant attention due to their ability to respond to external stimuli.In this work,dual temperature-responsive block copolymers are synthesized via reversible addition-fragmentation chain transfer polymerization(RAFT)polymerization utilizing zwitterionic monomer methacryloyl ethyl sulfobetaine(SBMA) and N-isopropyl acrylamide(NIPAAm) as monomers.The thermal responsive behaviors can be easily modulated by incorporating additional hydrophobic monomer benzyl acrylate(BN) or hydrophilic monomer acrylic acid(AA),adjusting concentration or pH,or varying the degree of polymerization of the block chain segments.The cloud points of the copolymers are determined by UV-Vis spectrophotometry,and these copolymers exhibit both controlled upper and lower critical solu bility temperatures(LCST and UCST) in aqueous solution.This study analyzes and summarizes the influencing factors of dual temperature responsive block copolymers by exploring the effects of various conditions on the phase transition temperature of temperature-sensitive polymers to explore the relationship between their properties and environment and structure to make them more selective in terms of temperature application range and regulation laws.It is very interesting that the introduction of poly-acrylic acid(PAA) segments in the middle of di-block copolymer PSBMA_(55)-b-PNIPAAm_(80) to form PSBMA_(55)-b-PAA_(x)-b-PNIPAAm_(80) results in a reversal of temperature-responsive behaviors from 'U'(LCST UCST) type,while the copolymer PSBMA_(55)-b-P(NIPAAm_(80)-co-AA_(x)) not.This work provides a clue for tuning the phase transition behavior of polymers for manufacture of extreme smart materials.

关键词： Temperature responsive polymers High critical solubility temperature(UCST) Low critical solubility temperature(LCST) Block copolymers