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Chinese Physics Letters 2001年第2期18卷 236-238页

作者： LI Chao-Hong DUAN Yi-Wu wing-ki liu Jian-Min Yuan Department of Physics Hu’nan Normal UniversityChangsha 410081 Department of Physics University of WaterlooWaterlooOntarioN2L3G1Canada Department of Physics and Atmospheric Science Drexel UniversityPhiladelphiaPA19104USA Laboratory of Magnetic Resonance and Atomic and Molecular Physics Wuhan Institute of Physics and MathematicsChinese Academy of SciencesWuhan 430071

Within Born--Oppenheimer approximation,by using the classical trajectory theory,a description for the high-order harmonic generation of the hydrogen molecular ion interacting with ultrashort laser pulses has been *** Coulomb singularities have been remedied by the *** action-angle variables have been used to generate the initial inversion symmetry microcanonical *** a proper intensity range,a harmonic plateau with only odd harmonics *** a larger intensity,because of the existence of chaos,the harmonic spectra become *** a large enough intensity,the ionization takes place and the harmonics *** the chaos causes the noises,the ionization suppresses the harmonic generation,and the onset of the ionization follows the onset of chaos.

关键词： harmonic harmonics chaos

Influence of laser fields on the vibrational population of molecules and its wave-packet dynamical investigation

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Chinese Physics B 2010年第12期19卷 193-202页

作者：王军刘芳岳大光赵娟许燕孟庆田 liu wing-ki College of Physics and Electronics Shandong Normal University Department of Physics and Astronomy University of Waterloo

The time-dependent wave packet method is used to investigate the influence of laser-fields on the vibrational population of molecules. For a two-state system in laser fields, the populations on different vibrational levels of the upper and lower electronic states are given by wavefunctions obtained by solving the Schrbdinger equation with the split- operator method. The calculation shows that the field parameters, such as intensity, wavelength, duration, and delay time etc. can have different influences on the vibrational population. By varying the laser parameters appropriately one can control the evolution of wave packet and so the vibrational population in each state, which will benefit the light manipulation of atomic and molecular processes.

关键词： intense laser field time-dependent wave packet method light-matter interaction vibrational population

R-Memcached: A Reliable In-Memory Cache for Big Key-Value Stores

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Tsinghua Science and Technology 2015年第6期20卷 560-573页

作者： Chengjian liu Kai Ouyang Xiaowen Chu Hai liu Yiu-wing Leung Department of Computer Science Hong Kong Baptist University Institute of Research and Continuing Education Hong Kong Baptist University

Large-scale key-value stores are widely used in many Web-based systems to store huge amount of data as(key, value) pairs. In order to reduce the latency of accessing such(key, value) pairs, an in-memory cache system is usually deployed between the front-end Web system and the back-end database system. In practice, a cache system may consist of a number of server nodes, and fault tolerance is a critical feature to maintain the latency Service-Level Agreements(SLAs). In this paper, we present the design, implementation, analysis, and evaluation of R-Memcached, a reliable in-memory key-value cache system that is built on top of the popular Memcached software. R-Memcached exploits coding techniques to achieve reliability, and can tolerate up to two node *** experimental results show that R-Memcached can maintain very good latency and throughput performance even during the period of node failures.

关键词： in-memory cache fault tolerance key-value store

Enriched reproducing kernel particle method for fractional advection–diffusion equation

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Acta Mechanica Sinica 2018年第3期34卷 515-527页

作者： Yuping Ying Yanping Lian Shaoqiang Tang wing Kam liu Laboratory of Computational Physics Institute of Applied Physics and Computational Mathematics College of Engineering Peking University Department of Mechanical Engineering Northwestern University HEDPS CAPT and LTCS Peking University

The reproducing kernel particle method （RKPM） has been efficiently applied to problems with large deformations, high gradients and high modal density. In this paper, it is extended to solve a nonlocal problem modeled by a fractional advectiondiffusion equation （FADE）, which exhibits a boundary layer with low regularity. We formulate this method on a moving least-square approach. Via the enrichment of fractional-order power functions to the traditional integer-order basis for RKPM, leading terms of the solution to the FADE can be exactly reproduced, which guarantees a good approximation to the boundary layer. Numerical tests are performed to verify the proposed approach.

关键词： Meshfree method Fractional calulus Enriched reproducing kernel Advection-diffusion equation Fractional-order basis

Deep CLSTM for Predictive Beamforming in Integrated Sensing and Communication-Enabled Vehicular Networks

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Journal of Communications and Information Networks 2022年第3期7卷 269-277页

作者： Chang liu Xuemeng liu Shuangyang Li Weijie Yuan Derrick wing Kwan Ng School of Electrical Engineering and Telecommunications the University of New South WalesSydneyNSW 2052Australia School of Electrical and Information Engineering the University of SydneySydneyNSW 2006Australia Department of Electrical Electronic and Computer Engineeringthe University of Western AustraliaPerth WA 6009Australia Department of Electrical and Electronic Engineering Southern University of Science and TechnologyShenzhen 518055China

Predictive beamforming design is an essential task in realizing high-mobility integrated sensing and communication(ISAC),which highly depends on the accuracy of the channel prediction(CP),i.e.,predicting the angular parameters of ***,the performance of CP highly depends on the estimated historical channel stated information(CSI)with estimation errors,resulting in the performance degradation for most traditional CP *** further improve the prediction accuracy,in this paper,we focus on the ISAC in vehicle networks and propose a convolutional long-short term memory(CLSTM)recurrent neural network(CLRNet)to predict the angle of vehicles for the design of predictive *** the developed CLRNet,both the convolutional neural network(CNN)module and the LSTM module are adopted to exploit the spatial features and the temporal dependency from the estimated historical angles of vehicles to facilitate the angle ***,numerical results demonstrate that the developed CLRNet-based method is robust to the estimation error and can significantly outperform the state-of-the-art benchmarks,achieving an excellent sum-rate performance for ISAC systems.

关键词： integrated sensing and communication predictive beamforming deep learning convolutional longshort term neural network vehicular networks

An efficient method for privacy preserving location queries

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Frontiers of Computer Science 2012年第4期6卷 409-420页

作者： Yubao liu Xiuwei CHEN Zhan LI Zhijie LI Raymond Chi-wing WONG Department of Computer Science Sun Yat-Sen UniversityGuangzhou 510006China Department of Computer Science Jinan UniversityGuangzhou 510632China Department of Computer Science and Engineering The Hong Kong University of Science and TechnologyHong KongChina

Recently, the issue of privacy preserving loca- tion queries has attracted much research. However, there are few works focusing on the tradeoff between location privacy preservation and location query information collection. To tackle this kind of tradeoff, we propose the privacy persevering location query （PLQ）, an efficient privacy pre-serving location query processing framework. This frame- work can enable the location-based query without revealing user location information. The framework can also facilitate location-based service providers to collect some information about the location based query, which is useful in practice. PLQ consists of three key components, namely, the location anonymizer at the client side, the privacy query processor at the server side, and an additional trusted third party connect- ing the client and server. The location anonymizer blurs the user location into a cloaked area based on a map-hierarchy. The map-hierarchy contains accurate regions that are parti- tioned according to real landforms. The privacy query pro- cessor deals with the requested nearest-neighbor （NN） loca- tion based query. A new convex hull of polygon （CHP） algo- rithm is proposed for nearest-neighbor queries using a poly- gon cloaked area. The experimental results show that our al- gorithms can efficiently process location based queries.

关键词： location based service (LBS) privacy preserva- tion nearest-neighbor (NN) location query

Fracture mechanics analysis on Smart-Cut~*** 2:Effect of bonding flaws

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Acta Mechanica Sinica 2009年第2期25卷 197-203页

作者： Bin Gu Hongyuan liu Yiu-wing Mai Xi Qiao Feng ShouWen Yu Centre for Advanced Materials Technology (CAMT) School of Aerospace Mechanical and MechatronicEngineering (AMME) J07 University of SydneySydney NSW 2006 Australia Department of Engineering Mechanics Tsinghua University Beijing 100084 China

In Part 2 of the paper on the Smart-Cut process, the effects of bonding flaws characterized by the size and internal pressure before and after splitting are studied by using fracture mechanics models. It is found that the bonding flaws with large size are prone to cause severe deviation of defect growth, leading to a non-transferred area of thin layer when splitting. In a practical Smart-Cut process where the internal pressure of bonding flaws is very small, large interfacial defects always promote defect growth in the splitting process. Meanwhile, increasing the internal pressure of the bonding flaws decreases the defect growth and its deviation before splitting. The mechanism of relaxation of stiffener constraint is proposed to clarify the effect of bonding flaws. Moreover, the progress of the splitting process is analyzed when bonding flaws are present. After splitting, those bonding flaws with large size and high internal pressure are vulnerable for the blistering of the thin film during high-temperature annealing.

关键词： Smart-Cut technology Fracture mechanics Stress intensity factor Interfacial defect

Bridging Atomistic/Continuum Scales in Solids with Moving Dislocations

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Chinese Physics Letters 2007年第1期24卷 161-164页

作者：唐少强 liu wing K KARPOV Eduard G. 侯一钊 LTCS Department of Mechanics and Aerospace Engineering Peking University Beijing 100871 Department of Mechanical Engineering Northwestern University Evanston IL 60208 USA Applied and Computational Mathematics California Institute of Technology Pasadena CA 91125 USA

We propose a multiscale method for simulating solids with moving dislocations. Away from atomistic subdomains where the atomistic dynamics are fully resolved, a dislocation is represented by a localized jump profile, superposed on a defect-free field. We assign a thin relay zone around an atomistic subdomain to detect the dislocation profile and its propagation speed at a selected relay time. The detection technique utilizes a lattice time history integral treatment. After the relay, an atomistic computation is performed only for the defect-free field. The method allows one to effectively absorb the fine scale fluctuations and the dynamic dislocations at the interface between the atomistic and continuum domains. In the surrounding region, a coarse grid computation is adequate.

关键词： multiscale method Moving Dislocations dislocation atomistic subdomain

DeepCAGE:Incorporating Transcription Factors in Genome-wide Prediction of Chromatin Accessibility

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Genomics, Proteomics & Bioinformatics 2022年第3期20卷 496-507页

作者： Qiao liu Kui Hua Xuegong Zhang wing Hung Wong Rui Jiang Ministry of Education Key Laboratory of Bioinformatics Bioinformatics DivisionBeijing National Research Center for Information Science and TechnologyCenter for Synthetic and Systems BiologyDepartment of AutomationTsinghua UniversityBeijing 100084China Department of Statistics Stanford UniversityStanfordCA 94305USA

Although computational approaches have been complementing high-throughput biological experiments for the identification of functional regions in the human genome,it remains a great challenge to systematically decipher interactions between transcription factors(TFs)and regulatory elements to achieve interpretable annotations of chromatin accessibility across diverse cellular *** solve this problem,we propose DeepCAGE,a deep learning framework that integrates sequence information and binding statuses of TFs,for the accurate prediction of chromatin accessible regions at a genome-wide scale in a variety of cell *** takes advantage of a densely connected deep convolutional neural network architecture to automatically learn sequence signatures of known chromatin accessible regions and then incorporates such features with expression levels and binding activities of human core TFs to predict novel chromatin accessible *** a series of systematic comparisons with existing methods,DeepCAGE exhibits superior performance in not only the classification but also the regression of chromatin accessibility *** a detailed analysis of TF activities,DeepCAGE successfully extracts novel binding motifs and measures the contribution of a TF to the regulation with respect to a specific locus in a certain cell *** applied to whole-genome sequencing data analysis,our method successfully prioritizes putative deleterious variants underlying a human complex trait and thus provides insights into the understanding of disease-associated genetic *** can be downloaded from https://***/kimmo1019/DeepCAGE.

关键词： Chromatin accessibility Deep learning Transcription factor Gene expression

Gut Microbiome in Colorectal Cancer:Clinical Diagnosis and Treatment

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Genomics, Proteomics & Bioinformatics 2023年第1期21卷 84-96页

作者： Yali liu Harry Cheuk-Hay Lau wing Yin Cheng Jun Yu Institute of Digestive Disease and The Department of Medicine and Therapeutics State Key Laboratory of Digestive DiseaseLi Ka Shing Institute of Health SciencesCUHK Shenzhen Research InstituteThe Chinese University of Hong KongHong Kong Special Administrative Region 999077China

Colorectal cancer(CRC)is one of the most frequently diagnosed cancers and the leading cause of cancer-associated *** studies have shown that both genetic and environmental risk factors contribute to the development of *** metagenomic studies of CRC have identified gut dysbiosis as a fundamental risk factor in the evolution of colorectal *** enormous efforts and substantial progresses have been made in understanding the relationship between human gut microbiome and CRC,the precise mechanisms involved remain *** data have shown a direct causative role of the gut microbiome in DNA damage,inflammation,and drug resistance in CRC,suggesting that modulation of gut microbiome could act as a powerful tool in CRC prevention and ***,we provide an overview of the relationship between gut microbiome and CRC,and explore relevant mechanisms of colorectal *** next highlight the potential of bacterial species as clinical biomarkers,as well as their roles in therapeutic *** limiting the clinical translation of gut microbiome and strategies for resolving current challenges are further discussed.

关键词： Gut microbiome Colorectal cancer Diagnostic biomarker Immunotherapy Chemotherapy