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Coexistence of All-Order Topological States in a Three-Dimensional Phononic Topological Crystalline Insulator

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Research 2024年第2期2023卷 511-518页

作者： Hua-Shan lai Hao Chen Chu-Hao Xia Si-yuan Yu Cheng He Yan-Feng Chen National Laboratory of Solid State Microstructures&Department of Materials Science and Engineering Nanjing UniversityNanjng 210093China Collaborative Innovation Center of Advanced Microstructures Nanjing University Nanjng 210093China Jiangsu Key Laboratory of Artificial Functional Materials Nanjing University Nanjing 210093China

Classical-wave topological materials lacking intrinsic half-integer spins are less robust while more ***,we explore a single 3-dimensional phononic topological crystalline insulator that simultaneously exhibits a whole family of first-order quadratic surface,second-order hinge,and third-order corner states within the same *** a topological crystalline insulator hosting all-order phases originates from the different topological nature when hierarchically projected onto different facets and lower dimensions,thus free from trivial cladding *** work offers an ideal platform for either robust wave propagation or localization in on-demand dimensions and may facilitate dimension division multiplexing technology.

关键词： topological dimensions crystalline

Impact of direct-acting antivirals on de novo occurrence of hepatocellular carcinoma in hepatitis C virus patients

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Hepatoma Research 2020年第6期6卷 33-40页

作者： Ming Yang Ruilan Ma yuan Huang lai Wei Hepatopancreatobiliary Center Beijing Tsinghua Changgung HospitalTsinghua UniversityBeijing 102218China Department of radiotherapy The Second Hospital of Dalian Medical UniversityDalianLiaoning 116027China

Hepatitis C Virus(HCV)infection constitutes a significant burden to world health,leading to liver cirrhosis and hepatocellular carcinoma(HCC).In the past decades,pegylated interferon combined with ribavirin has been used extensively for HCV treatment,and interferon(IFN)is thought to have antitumor ***-acting antivirals(DAAs)have fundamentally changed HCV therapy,due to their high efficacy and ***,recent studies have reported relatively high rates of HCC occurrence,and recurrence,following successful HCV treatment using *** studies were grossly underpowered due to their retrospective design,lack of untreated or IFN controls,small sample size,and limited patient follow-up *** then,many retrospective and prospective cohort studies with larger size and longer follow-up duration after DAAs therapy have been *** studies showed that treatment with DAAs can reduce the risk of HCC compared to no treatment,didn't increase the risk of HCC compared to IFN-based therapy after adjusting for the potential confounders of these two groups,and DAAs-induced sustained virological response decreased the risk of HCC compared to DAAs treatment *** conclusion,DAAs treatment doesn't appear to increase the development of HCC,even in cirrhotic ***,cirrhotic patients should be monitored for the development of HCC during and after DAAs treatment.

关键词： Sustained virological response hepatocellular carcinoma liver cirrhosis

Electrochemical Performance and Capacity Fading Mechanism of LiFePO4 at Different pH Aqueous Electrolyte Solutions

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Chinese Journal of Chemical Physics 2015年第3期28卷 315-322,I0002页

作者： yuan Yin Yue-hua Wen Yong-lai Lu Jie Cheng Gao-ping Cao Yu-sheng Yang College of Materials Science and Engineering Beijing University of Chemical Technology Beijing 100029 China Research Institute of Chemical Defence Beijing 100191 China

The electrochemical stability of LiFePO4 in a Li＋-containing aqueous electrolyte solution is critically dependent on the pH value of the aqueous solution. It shows a considerable decay in capacity of LiFePO4 upon cycling when the pH value is increased to 11. The mechanism responsible for the capacity fading is extensively investigated by means of cyclic voltammogram, ac impedance, charge/discharge, ex situ X-ray diffraction, and chemical analysis. LiFePO4 is relatively electrochemically stable in LiNO3 aqueous solution with pH=7. But the electrochemical performance of LiFePO4 in aqueous electrolyte is inferior to that in organic electrolyte. It is attributed to the loss of Li and the Fe, P dissolution during prolonged charge-discharge in aqueous medium. A precipitate is formed on the surface of LiFePO4 electrodes. It results in the change of crystalline structure, a large electrode polarization, and capacity fading.

关键词： Olivine LiFePOa Aqueous electrolyte Electrochemical property Capacityfade Mechanism

Heat treatment enhancing the compressive fatigue properties of open-cellular Ti-6Al-4V alloy prototypes fabricated by electron beam melting

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Journal of Materials Science & Technology 2018年第7期34卷 1127-1131页

作者： Wei yuan Wentao Hou Shujun Li Yulin Hao Rui Yang lai-Chang Zhang Yue Zhu Department of Orthopedics First Hospital of China Medical University Shenyang National Laboratory for Materials Science Institute of Metal Research Chinese Academy of Sciences School of Engineering Edith Cowan University

In this work, we report the effect of annealing in α＋β phase field on the fatigue properties of Ti-6A1-4V alloy meshes fabricated by electron beam melting. The results show that annealing at high temperature near the phase boundary enhances the ductility of the brittle mesh struts due to the formation of coarse α lamellas with a large thickness/length ratio. Accordingly, the fatigue endurance ratio of the studied meshes increases to up to -0.6, which is much superior to that of the as-fabricated counterparts and comparable to those of dense materials.2018 Published by Elsevier Ltd on behalf of The editorial office of Journal of Materials Science ＆ Technology.

关键词： Titanium alloy Reticulated mesh Annealing treatment Morphology Fatigue endurance

Condensation of Aromatic Aldehydes with Isopropylidene Malonate or 5,5-Dimethyl-1,3-cyclohexanedion without Catalyst

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Chinese Chemical Letters 1997年第9期8卷 755-758页

作者： Dai Qing SHI yuan GAO lai Laong MU Zai Sheng LU Gui yuan DAI(Department of Chemistry, Xuzhou Normal University, Xuzhou 221009) Department of Chemistry Xuzhou Normal University Xuzhou 221009 China

The condensation of aromatic aldehydes with isopropylidene malonate or 5,5-dimethyl-1,3-cyclohexanedione is carried out by DMF as solvent without catalyst.

关键词： IR HNMR Cl ppm Condensation of Aromatic Aldehydes with Isopropylidene Malonate or 5,5-Dimethyl-1,3-cyclohexanedione without Catalyst KBr

Ancient DNA sequences from Coelodonta antiquitatis in China reveal its divergence and phylogeny

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Science China Earth Sciences 2014年第3期57卷 388-396页

作者： yuan JunXia SHENG GuiLian HOU XinDong SHUANG XiaoYan YI Jian YANG Hong lai XuLong State Key Laboratory of Biogeology and Environmental Geology China University of Geosciences Faculty of Material Science and Chemistry China University of Geosciences Department of Science and Technology Bryant University 1150 Douglas Pike Smithfield

Ancient DNA data have supported a sister relationship between woolly rhinoceros and extant Sumatran *** relationship has been used to explore the divergent times for the woolly rhinoceros from their *** and partial ancient DNA sequences of the mitochondrial cytochrome b(cyt b)gene were retrieved from bones of the late Pleistocene Coelodonta antiquitatis excavated from northern and northeastern *** newly obtained sequences together with the European and northern Asian Coelodonta antiquitatis sequences from GenBank were used to estimate the evolutionary divergence *** analyses showed the exchange of genetic information between the Chinese individuals and Coelodonta antiquitatis of north Asia,which also indicated a more recent evolutionary timescale(3.8–4.7 Ma)than previous molecular estimations(17.5–22.8 or 21–26 Ma)for woolly rhinoceros based on the fossil calibration of *** new timescale was more consistent with the fossil record of the earliest known genus Coelodonta.

关键词： Coelodonta antiquitatis cytochrome b gene divergence time phylogeny

Variational learning for finite Beta-Liouville mixture models

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The Journal of China Universities of Posts and Telecommunications 2014年第2期21卷 98-103页

作者： lai Yu-ping ZHOU Ya-jian PING yuan GUO Yu-cui YANG Yi-xian Information Security Center Beijing University of Posts and Telecommunications Department of Computer Science and Technology Xuchang University School of Science Beijing University of Posts and Telecommunications

In the article, an improved variational inference （VI） framework for learning finite Beta-Liouville mixture models （BLM） is proposed for proportional data classification and clustering. Within the VI framework, some non-linear approximation techniques are adopted to obtain the approximated variational object functions. Analytical solutions are obtained for the variational posterior distributions. Compared to the expectation maximization （EM） algorithm which is commonly used for learning mixture models, underfitting and overfitting events can be prevented. Furthermore, parameters and complexity of the mixture model （model order） can be estimated simultaneously. Experiment shows that both synthetic and real-world data sets are to demonstrate the feasibility and advantages of the proposed method.

关键词： variational inference model selection factorized approximation Beta-Liouville distribution mixing modeling

Study of the crosstalk evaluation for cavity BPM

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Nuclear Science and Techniques 2018年第6期29卷 67-75页

作者： Jian Chen Yong-Bin Leng Lu-Yang Yu Long-Wei lai Ren-Xian yuan Shanghai Institute of Applied Physics Chinese Academy of Science Shanghai 201204 China University of the Chinese Academy of Science Beijing 100049 China

In order to pursue high-precision beam position measurements for free-electron laser facilities, a cavity beam position monitor(CBPM) is employed to measure the transverse position that can meet the requirement of position resolution at a sub-micrometer or even nanometer scale. However, for the pill-box cavity BPM, crosstalk between the cavities will have an effect on the accurate measurement of beam position. To reduce the effect of crosstalk on CBPM performance and ease the measurement of the isolation between the cavities, the cavities with a slight difference in resonant frequency were designed and applied in the Dalian coherent light source and Shanghai soft X-ray free-electron laser facilities. Furthermore, two methods, the principal component analysis method and the method of harmonic analysis, are proposed in this paper to evaluate the crosstalk. The results demonstrate that the two methods are feasible in evaluating the crosstalk between the cavities.

关键词： BPM 串音评估位置分辨率学习精确测量激光设备主要部件

Supernova neutrinos in a strangeon star model

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Research in Astronomy and Astrophysics 2017年第9期17卷 39-50页

作者： Mao yuan Ji-Guang Lu Zhi-Liang Yang Xiao-Yu lai Ren-Xin Xu Department of Astronomy Beijing Normal UniversityBeijing 100875China School of Physics Peking UniversityBeijing 100871China School of Physics and Engineering Hubei University of EducationWuhan 430205China Kavli Institute for Astronomy and Astrophysics at Peking University Beijing 100871China

The neutrino burst detected during supernova SN 1987A is explained in a strangeon star model, in which it is proposed that a pulsar-like compact object is composed of strangeons （strangeon： an abbreviation for ＂strange nucleon＂）. A nascent strangeon star＇s initial internal energy is calculated, with the inclusion of pion excitation （energy around 1053 erg, comparable to the gravitational binding energy of a collapsed core）. A liquid-solid phase transition at temperature - 1 - 2 MeV may occur only a few tens of seconds after core collapse, and the thermal evolution of a strangeon star is then modeled. It is found that the neutrino burst observed from SN 1987A can be reproduced in such a cooling model.

关键词： stars neutron -- supernovae individual (SN 1987A)- neutrinos