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Unusual photocarrier and coherent phonon dynamics behaviors of layered PdSe_(2)unveiled by ultrafast spectroscopy of the edge surface

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Science China(Physics,Mechanics & Astronomy) 2024年第8期67卷 143-152页

作者： Tiantian Yun Changfu Huo Jinluo Cheng zhi-bo liu Xiao-Qing Yan Key Laboratory of Weak-Light Nonlinear Photonics Ministry of EducationSchool of PhysicsNankai UniversityTianjin 300071China Collaborative Innovation Center of Extreme Optics Shanxi UniversityTaiyuan 030006China GPL Photonics Laboratory Key Laboratory of Luminescence Science and TechnologyChinese Academy of Sciences&State Key Laboratory of Luminescence Science and ApplicationsChangchun Institute of OpticsFine Mechanics and PhysicsChinese Academy of SciencesChangchun 130033China

Layered materials exhibit different electronic and phonon properties along in-plane and out-of-plane directions;existing studies focus on their in-plane behaviors,and the influence of such anisotropies on the dynamics of photocarriers and phonons is ***,we fabricate layered PdSe_(2)crystals with flat edge surfaces and compare the time-resolved ultrafast spectroscopies on their basal and edge *** differences in the transient reflection spectroscopies reveal the inconsistent photocarrier and phonon dynamics behaviors on the two surfaces:the slow hot carrier relaxation process is accelerated and the thermoelasticity-induced longitudinal coherent acoustic phonon oscillation completely vanishes on the edge surface,as compared with the basal *** analysis reveals that the inconsistent hot carrier dynamics originate from the anisotropic properties of low-energy phonons in PdSe_(2),and the absence of phonon oscillation on the edge surface results from the wavevector-limited sensitivity of acoustic B_(1u)***,polarization-dependent spectroscopies indicate the diverse optical anisotropies beyond the in-plane of PdSe_(2).This work provides a new method to explore unique physical properties and modulate the optical anisotropy of layered materials.

关键词： PdSe_(2) ultrafast spectroscopy edge surface carrier dynamics coherent phonon oscillation anisotropy

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Stacking of Exfoliated Two-Dimensional Materials: A Review

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Chinese Journal of Chemistry 2020年第9期38卷 981-995页

作者： Zhen Hu zhi-bo liu Jian-Guo Tian The Key Laboratory of Weak Light Nonlinear Photonics Ministry of EducotionTEDA Applied Physics Institute ond School of PhysicsNankai University Tianjin 300071China Renewable Energy Conversion and Storage Center Nankai UniversityTionjin 300384China

In recent years,two-dimensfonal(2D)atomic crystals represented by graphene have opened up new fields of 2D *** materials with atomic layer thickness are self-assembled into van der Waals heterostructures by weak van der Waals forces without considering lattice *** der Waals heterostructures can not only enhance the performance of its constituent materials but also show new ***-quality heterostructures require mechanically cleaved intrinsic 2D materials and flexible 2D material stacking ***,we summarize in detail the reliable exfoliation methods for large-area single-layer 2D materials and the dry and wet stacking techniques with high success *** twisted bilayer graphene is used as an example to briefly introduce the single-crystal tearing method,which is currently the most practical method for preparing isotropic twisted heterostructures with high-precision rotation *** hope to provide a valuable reference for researchers of 2D materials.

关键词： twisted preparing method

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High Efficient Extraction of Phthalates in Aquatic Products by a Modified QuEChERS Method

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Chemical Research in Chinese Universities 2013年第4期29卷 653-656页

作者： WANG Wen-wen GAO Fu-kai LI Gui-zhi liu Zhen-bo liu Yong-ming College of Chemistry and Chemical Engineering Yantai University Yantai 264005 P. R. China

A simple, environmentally friendly and high efficient extraction method was proposed for the determina- tion of five phthalates in aquatic products by gas chromatography combined with mass spectrometry detector （GC-MS）. When this method was adopted, samples were pretreated by modified QuEChERS（quick, easy, cheap, effective, rugged and safe） method. An environmentally friendly extractant（ethanol aqueous solution） replaced toxic acetonitrile for extracting phthalates in the protein-matrix samples. Fluorescence quenching spectra of bovine serum albumin（BSA） with phthalates show that there was a high-affinity interaction between phthalate and protein, de- creasing the extraction efficiency of phthalates from fish samples. However, in the 80%（volume fraction, ~） ethanol aqueous solution, a slow but full protein denaturation takes place, which would cause the unfolding of protein and the release of phthalates. Meanwhile, the fat-soluble impurities are extracted less in ^（ethanol） 80% aqueous solution than in either ~p（ethanol） 100% or hydrophobic solvents in the liquid-liquid extraction procedure. Therefore the puri- fication steps were greatly simplified. Overall recoveries were 81.77%--90.5% with limits of detection between 2.53 and 9.61 ~tg/L, and relative standard deviation values at 1.15%---4.85%. The proposed approach was satisfactorily applied to the determination of phthalates in real aquatic products, such as fish, shrimp and oyster.

关键词： Phthalate Modified quick, easy, cheap, effective, rugged and safe(QuEChERS) method Protein Aquatic product Gas chromatography-mass spectrometry-selected ion monitoring(GC-MS-SIM)

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Pulmonary aspergillosis with in-situ pulmonary artery thrombosis: to anti-coagulate or not?

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Chinese Medical Journal 2019年第14期132卷 1742-1744页

作者： zhi-bo liu Wan-Mu Xie Zhen-Guo Zhai Bin Cao Jun Wan Department of Pulmonary and Critical Care Medicine Center of Respiratory MedicineChina-Japan Friendship Hospital/Institute of Respiratory MedicineChinese Academy of Medical Sciences/National Clinical Research Center for Respiratory DiseasesBeijing 100029China

Aspergillus is widespread in the environment and causes a variety of tracheobronchial and pulmonary disorders,depending upon the alterations of immune status of hosts.[1] Among the spectrum of pulmonary aspergillosis (PA),allergic bronchopulmonary aspergillosis,and most chronic pulmonary aspergillosis are considered as noninvasive diseases,whereas invasive pulmonary aspergillosis (IPA) and subacute invasive pulmonary aspergillosis (SAIA) may cause tissue invasion.

关键词： pulmonary artery thrombosis pulmonary aspergillosis (PA) invasive pulmonary aspergillosis (IPA) subacute invasive pulmonary aspergillosis (SAIA)

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Tjong:A transformer‐based Mahjong AI via hierarchical decision‐making and fan backward

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CAAI Transactions on Intelligence Technology 2024年第4期9卷 982-995页

作者： Xiali Li bo liu zhi Wei Zhaoqi Wang Licheng Wu School of Information and Engineering Minzu University of ChinaBeijingChina Key Laboratory of Ethnic Language Intelligent Analysis and Security Governance of MOE Minzu University of ChinaBeijingChina Department of Computer Science New Jersey Institute of TechnologyNewarkNew JerseyUSA

Mahjong,a complex game with hidden information and sparse rewards,poses significant *** Mahjong AIs require substantial hardware resources and extensive datasets to enhance AI *** authors propose a transformer‐based Mahjong AI(Tjong)via hierarchical decision‐*** utilising self‐attention mechanisms,Tjong effectively captures tile patterns and game dynamics,and it decouples the decision pro-cess into two distinct stages:action decision and tile *** design reduces de-cision complexity ***,a fan backward technique is proposed to address the sparse rewards by allocating reversed rewards for actions based on winning *** consists of 15M parameters and is trained using approximately 0.5 M data over 7 days of supervised learning on a single server with 2 *** action decision achieved an accuracy of 94.63%,while the claim decision attained 98.55%and the discard decision reached 81.51%.In a tournament format,Tjong outperformed AIs(CNN,MLP,RNN,ResNet,VIT),achieving scores up to 230%higher than its ***-more,after 3 days of reinforcement learning training,it ranked within the top 1%on the leaderboard on the botzone platform.

关键词： decision making deep learning deep neural networks

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Optical anisotropy of black phosphorus by total internal reflection

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Nano Materials Science 2019年第4期1卷 304-309页

作者： Wei Xin Hao bo Jiang Teng Qian Sun Xiao Guang Gao Shao Nan Chen bo Zhao Jian Jun Yang zhi bo liu Jian Guo Tian Chun Lei Guo The Guo China-U.S.Photonics Lab State Key Laboratory of Applied OpticsChangchun Institute of OpticsFine Mechanicsand PhysicsChangchun130033China The Key Laboratory of Weak Light Nonlinear Photonics Ministry of EducationTeda Applied Physics InstituteAnd School of PhysicsNankai UniversityTianjin300071China The Key Laboratory of Bionic Engineering Ministry of EducationJilin UniversityChangchun130023China The Institute of Optics University of RochesterRochesterNY14627USA

Although abundant research on the anisotropy of van der Waals(vd W)materials has been published,we undertake an in-depth study of their optical properties as they have an important guiding role for light control in two-dimensional(2D)*** an example,we study the reflectance of few-layered black phosphorus(BP)in the total internal reflection(TIR)mode in *** demonstrate that its optical anisotropy can be changed on a large scale by varying the incident angles,polarization states,and the in-plane rotation angles of the BP *** analysis indicates that the phenomena observed are common to all the atom-thick biaxial crystals,so these conclusions can be widely applied to other anisotropic 2D *** research furthers the current understanding of the properties of BP more comprehensively,and provides guidance for developing new optoelectronic applications,especially when BP and other atom-thick biaxial crystals are integrated with TIR devices.

关键词： Black phosphorus Optical anisotropy Total internal reflection Biaxial crystal

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A rare 3D hybrid bimetal halide ferroelectric:(3-Hydroxypyrrolidinium)2RbBiBr6

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Science China Materials 2022年第10期65卷 2879-2883页

作者： Lei He Ke Xu Ping-Ping Shi zhi-bo liu Wen Zhang Qiong Ye Jiangsu Key Laboratory for Science and Applications of Molecular Ferroelectrics and School of Chemistry and Chemical Engineering Southeast UniversityNanjing 211189China

Organic-inorganic hybrid metal halides have gained worldwide attention due to their structural diversity and intriguing physical&chemical properties[1–5].The metal halides hold great promise in micro-and nano-electronics,energy storage,photocatalysis,optoelectronics and photovoltaics[6–9].In particular,photovoltaic devices containing a compositional derivative of the hybrid metal halide methylammonium lead halide(CH_(3)-NH_(3)PbX_(3),X=Cl,Br or I)have demonstrated remarkably high photoconversion efficiencies[10,11].

关键词：铁电体金属卤化物铁电材料居里温度有机阳离子热释电系数光伏器件拓扑结构

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Recent Advances in MoiréSuperlattice Structures of Twisted Bilayer and Multilayer Graphene

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Chinese Physics Letters 2022年第3期39卷 54-81页

作者： Xiao-Feng Li Ruo-Xuan Sun Su-Yun Wang Xiao Li zhi-bo liu Jian-Guo Tian The Key Laboratory of Weak Light Nonlinear Photonics(Ministry of Education) School of Physics and Teda Applied Physics InstituteNankai UniversityTianjin 300071China Department of Physics City University of Hong KongKowloonHong KongChina Renewable Energy Conversion and Storage Center Nankai UniversityTianjin 300071China The Collaborative Innovation Center of Extreme Optics Shanxi UniversityTaiyuan 030006China

Twisted bilayer graphene(TBG),which has drawn much attention in recent years,arises from van der Waals materials gathering each component together via van der Waals *** is composed of two sheets of graphene rotated relatively to each ***épotential,resulting from misorientation between layers,plays an essential role in determining the band structure of TBG,which directly relies on the twist *** the twist angle approaches a certain critical value,flat bands will show up,indicating the suppression of kinetic energy,which significantly enhances the importance of Coulomb interaction between *** a result,correlated states like correlated insulators emerge from ***,superconductivity in TBG is also reported in many experiments,which drags researchers into thinking about the underlying ***,the interest in the atomic reconstruction of TBG at small twist angles comes up and reinforces further understandings of properties of *** addition,twisted multilayer graphene receives more and more attention,as they could likely outperform TBG although they are more difficult to handle *** this review,we mainly introduce theoretical and experimental progress on *** the basic knowledge of TBG,we emphasize the essential role of atomic reconstruction in both experimental and theoretical *** consideration of atomic reconstruction in small-twist situations can provide us with another aspect to have an insight into physical mechanism in *** addition,we cover the recent hot topic,twisted multilayer *** the bilayer situation can be relatively easy to resolve,multilayer situations can be really complicated,which could foster more unique and novel ***,in the end of the review,we look forward to future development of twisted multilayer graphene.

关键词： twist twisted multilayer

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Sign of differential reflection and transmission in pump-probe spectroscopy of graphene on dielectric substrate

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Photonics Research 2015年第2期3卷 1-9页

作者： Chengmin Gao Xin Zhao Jun Yao Xiao-Qing Yan Xiang-Tian Kong Yongsheng Chen zhi-bo liu Jian-Guo Tian The Key Laboratory of Weak Light Nonlinear Photonics Ministry of EducationTeda Applied Physics Institute and School of PhysicsNankai University College of Science Tianjin Polytechnic University The Key Laboratory of Functional Polymer Materials and Center for Nanoscale Science&Technology Institute of Polymer ChemistryCollege of ChemistryNankai University

Pump-probe differential reflection and transmission spectroscopy is a very effective tool to study the nonequilibrium carrier dynamics of graphene. The reported sign of differential reflection from graphene is not explicitly explained and not consistent. Here, we study the differential reflection and transmission signals of graphene on a dielectric substrate. The results reveal the sign of differential reflection changes with the incident direction of the probe beam with respect to the substrate. The obtained theory can be applied to predict the differential signals of other two-dimensional materials placed on various dielectric substrates.

关键词： Sign of differential reflection and transmission in pump-probe spectroscopy of graphene on dielectric substrate Case

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Morphological Classification of Infrared Galaxies Based on WISE

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Research in Astronomy and Astrophysics 2024年第4期24卷 222-236页

作者： zhi-Ren Pan bo Qiu Cui-Xiang liu A-Li Luo Xia Jiang Xiao-Yu Guo School of Electronic and Information Engineering Hebei University of TechnologyTianjin 300401China Key Laboratory of Optical Astronomy National Astronomical ObservatoriesChinese Academy of SciencesBeijing 100101China

This study introduces a novel convolutional neural network,the WISE Galaxy Classification Network(WGC),for classifying spiral and elliptical galaxies using Wide-field Infrared Survey Explorer(WISE)*** attains an accuracy of 89.03%,surpassing the combined use of K-means or SVM with the Color-Color method in more accurately identifying galaxy *** enhanced variant,WGC_mag,integrates magnitude parameters with image features,further boosting the accuracy to 89.89%.The research also delves into the criteria for galaxy classification,discovering that WGC primarily categorizes dust-rich images as elliptical galaxies,corresponding to their lower star formation rates,and classifies less dusty images as spiral *** paper explores the consistency and complementarity of WISE infrared images with SDSS optical images in galaxy morphology *** SDSS Galaxy Classification Network(SGC),trained on SDSS images,achieved an accuracy of 94.64%.The accuracy reached 99.30% when predictions from SGC and WGC were *** the complementarity of features in WISE and SDSS images,a novel variant of a classifier,namely the Multi-band Galaxy Morphology Integrated Classifier,has been *** classifier elevates the overall prediction accuracy to 95.39%.Lastly,the versatility of WGC was validated in other data *** the HyperLEDA data set,the distinction between elliptical galaxies and Sc,Scd and Sd spiral galaxies was most pronounced,achieving an accuracy of 90%,surpassing the classification results of the Galaxy Zoo 2 labeled WISE data *** research not only demonstrates the effectiveness of WISE images in galaxy morphology classification but also represents an attempt to integrate multi-band astronomical data to enhance understanding of galaxy structures and evolution.

关键词： methods:data analysis infrared:galaxies galaxies:spiral galaxies:elliptical and lenticular cD

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