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Journal of Harbin Institute of Technology(New Series) 2014年第3期21卷 121-128页

作者： chuan-kai niu Yu-Fei Tan School of Municipal & Environment Engineering Harbin Institute of Technology

One of the major technical challenges in using carbon dioxide( CO2) as part of the cushion gas of the underground gas storage reservoir( UGSR) is the mixture of CO2and natural gas. To decrease the mixing extent and manage the migration of the mixed zone,an understanding of the mechanism of CO2and natural gas mixing and the diffusion of the mixed gas in aquifer is necessary. In this paper,a numerical model based on the three dimensional gas-water two-phase flow theory and gas diffusion theory is developed to understand this mechanism. This model is validated by the actual operational data in Dazhangtuo UGSR in Tianjin City,*** the validated model,the mixed characteristic of CO2and natural gas and the migration mechanism of the mixed zone in an underground porous reservoir is further studied. Particularly,the impacts of the following factors on the migration mechanism are studied: the ratio of CO2injection,the reservoir porosity and the initial operating pressure. Based on the results,the optimal CO2injection ratio and an optimal control strategy to manage the migration of the mixed zone are obtained. These results provide technical guides for using CO2as cushion gas for UGSR in real projects.

关键词： underground gas storage reservoir(UGSR) cushion gas carbon dioxide mixed zone porous media

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面向工业互联网的语义编码传输方法及应用

中山大学学报（自然科学版）（中英文） 2025年第1期64卷 51-60页

作者：牛凯鲁延鹏董超北京邮电大学人工智能学院北京100876 泛网无线通信教育部重点实验室北京100876 鹏城实验室广东深圳518055

通过将语义通信技术引入工业网络,构建了一个面向工业互联网的语义编码传输系统。系统中设计了语义编解码器以提取信源中的语义信息,相对于传统通信系统,基于语义信息的通信有更高的信息压缩效率与更高的符号差错容忍能力。同时引入信... 详细信息

通过将语义通信技术引入工业网络,构建了一个面向工业互联网的语义编码传输系统。系统中设计了语义编解码器以提取信源中的语义信息,相对于传统通信系统,基于语义信息的通信有更高的信息压缩效率与更高的符号差错容忍能力。同时引入信源信道联合编解码器,以信源信道联合编码的方式将语义信息转化为信道符号传输,进一步提升系统对工业网络通信资源的利用效率。所有编解码器均构建在深度神经网络架构Transformer上,确保了编解码器对语义信息的理解能力及系统的泛化能力。在工业药品生产场景中,对该系统进行测试,结果显示:相较于传统通信方案,该语义编码传输系统在图像重建质量和传输处理速度方面均有显著提升。且系统对下游任务的性能影响极小,保证了工业生产中如缺陷检测等关键任务的准确性。

关键词：工业互联网数据压缩与传输语义通信深度学习

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Exciton Bose–Einstein Condensation in Transition Metal Dichalcogenide Monolayer under In-Plane Magnetic Fields

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Chinese Physics Letters 2024年第8期41卷 69-76页

作者： Dengfeng Wang Yingda Chen Zhi-chuan niu Wen-kai Lou kai Chang SKLSM Institute of SemiconductorsChinese Academy of SciencesBeijing 100083China College of Materials Science and Opto-electronic Technology Center of Materials Science and Optoelectronics EngineeringUniversity of Chinese Academy of SciencesBeijing 100049China School of Physics Zhejiang UniversityHangzhou 310027China

Based on the Gross–Pitaevskii equation,we theoretically investigate exciton Bose–Einstein condensation(BEC)in transition metal dichalcogenide monolayers(TMDC-MLs)under in-plane magnetic *** observe that the in-plane magnetic fields exert a strong influence on the exciton BEC wave functions in TMDC-MLs because of the mixing of the bright and dark exciton states via Zeeman *** leads to the brightening of the dark exciton BEC *** competition between the dipole–dipole interactions caused by the long-range Coulomb interaction and the Zeeman effect induced by the in-plane magnetic fields can effectively regulate dark exciton BEC *** findings emphasize the utility of TMD-MLs as platforms for investigating collective phenomenon involving excited states.

关键词： effect Einstein dipole

Generic Exponential Sums Associated with Polynomials of Degree 3 in Two Variables

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Acta Mathematica Sinica,English Series 2012年第11期28卷 2301-2312页

作者： chuan Ze niu School of Mathematical Sciences Liaocheng University School of Mathematical Sciences Beijing Normal University

The generic Newton polygon of L-functions associated with the exponential sums of poly- nomials of degree 3 in two variables is studied by Dwork＇s analytic methods. Wan＇s conjecture is shown to be true for this case.

关键词： L-Function exponential sums generic Newton polygon two variables

A fully nonlinear approach for efficient ship-wave simulation

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Journal of Hydrodynamics 2023年第6期35卷 1027-1040页

作者： kai-yuan Shi Ren-chuan Zhu School of Naval Architecture Ocean and Civil EngineeringShanghai Jiao Tong UniversityShanghai200240China

This paper presents an efficient time-domain method for simulating nonlinear ship *** proposed method,implemented in an earth-fixed coordinate system,integrates a compact boundary element domain within a high-order spectral layer,enabling accurate modeling of both near-field and far-field ship *** overset mesh method and an attention mechanism are employed to track the moving *** effectiveness of the method is validated through simulations of Wigley and Series 60 ships sailing at various *** numerical results,including the nonlinear wave run-up at the ship bow,surface pressure distribution on the hull,and the ship resistance,agree well with experimental data and published numerical results,confirming that the method is capable of accurately simulating the nonlinear ship waves.

关键词： Fully nonlinear ship wake potential flow spectral coupled method wave-making resistance

ANALYSIS OF BATCH ARRIVAL QUEUE WITH RANDOMIZED VACATION POLICY AND AN UN-RELIABLE SERVER

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Journal of Systems Science & Complexity 2012年第4期25卷 759-777页

作者： Jau chuan KE kai Bin HUANG Department of Applied Statistics National Taichung University of Science and Technology Department of Engineering Information System Development Ardebtec Corporation Ltd.

This paper examines an M[x]/G/1 queueing system with an unreliable server and a delayed repair, in which the server operates a randomized vacation policy with multiple vacations. Whenever the system is empty, the server immediately takes a,vacation. If there is at least one customer found waiting in the queue upon returning from a vacation, the server will be immediately activated for service. Otherwise, if no customers are waiting for service at the end of a vacation, the server either remains idle with probability p or leaves for another vacation with probability 1 -p. Whenever one or more customers arrive when the server is idle, the server immediately starts providing service for the arrivals. The server may also meet an unpredictable breakdown and the repair may be delayed. For such a system the authors derive the distributions of some important system characteristics, such as the system size distribution at a random epoch and at a departure epoch, the system size distribution at the busy period initiation epoch, and the distribution of the idle period and the busy period. The authors perform a numerical analysis for changes in the system characteristics, along with changes in specific values of the system parameters. A cost effectiveness maximization model is constructed to explain the benefits of such a queueing system.

关键词： Cost effectiveness delayed repair randomized vacation queue reliability.

Internal Conversion Process of Chlorophyll a in Solvents in Femtosecond Pump-Probe Laser Fields

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Chinese Journal of Chemical Physics 2008年第3期21卷 211-216页

作者： kai niu Li-qing Dong Shu-lin Cong Department of Physics Dalian University of Technology Dalian 116024 China

The internal conversion （IC） processes of chlorophyll a （chl-a） in solvents are studied based on the reduced density matrix theory. The IC times can be obtained by simulating the experimental fluorescence depletion spectra （FDS）. The calculated IC times of chl-a in ethyl acetate, tetrahydrofuran and dimethyl formamide are 141, 147, and 241 fs, respectively. The oscillation feature of the FDS results from the forward and backward transfer of the population between coupled electronic states. The effects of diabatic coupling between two electronic states on the IC time and the FDS are described. The influence of molecule-reservoir coupling on the IC time is also investigated.

关键词： Fluorescence depletion spectrum Internal conversion Reduced density matrix

Arbitrary Decode-Forward Relaying with Re-Encoded Bits Selection Strategy for Polar Codes

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China Communications 2023年第8期20卷 153-162页

作者： Di Guan kai niu Chao Dong Key Laboratory of Universal Wireless Communication Ministry of EducationBeijing University of Posts and TelecommunicationsBeijing 100876China

In this paper,we propose an arbitrary decode-forward single-relay scheme for finite blocklength polar codes,which can be applied to the general symmetric discrete memoryless relay channel with orthogonal receiver *** relay node decodes the received *** relay node selectively re-encodes the message and transmits it to the destination ***,in order to minimize the upper-bound of the block error probability,we propose a selection strategy to decide the proper re-encoded bit set by the *** results are presented to illustrate the improvement in decoding performance of the proposed scheme compared to conventional relay schemes in both additive white Gaussian noise(AWGN)channel and Rayleigh fading channel(RFC).

关键词： polar codes decode-and-forward relaying arbitrary relay channel block error rate estimation

Cage-like radiotherapy system for noncoplanar radiotherapy

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Nuclear Science and Techniques 2021年第2期32卷 1-10页

作者： chuan-Meng niu Ming-Hui Li Jian-Rong Dai Department of Radiation Oncology National Cancer Center/National Clinical Research Center for Cancer/Cancer HospitalChinese Academy of Medical Sciences and Peking Union Medical CollegeBeijing 100021China

The aim of this study was to design a cage-like radiotherapy system(CRTS)to further promote the clinical application of noncoplanar *** CRTS comprises two stands,two O-rings,several arc girders,an X-ray head,an imaging subsystem,and a treatment *** X-ray head rotates with O-rings around the patient’s body and slides along the arc *** with the C-arm linear accelerator(C-Linac),the clinically available spatial irradiation angle ranges(SIARs)of the CRTS for the head,chest,and abdomen were 33%,63.6%,and 62.6%larger,***,according to a preliminary planning comparison based on the dose distribution simulation method,the CRTS achieved much better protection of normal tissue than the ***,the CRTS enabled accurate noncoplanar irradiation without movement of the body being irradiated,allowed automatic control of the movements of different parts without risk of collisions,and provided continuous radiation over an angle that considerably exceeded a full *** advantages make CRTS very promising for noncoplanar radiotherapy.

关键词： Radiotherapy system Noncoplanar radiotherapy Spatial irradiation angle range Spherical surface area

The feasibility for natural graphite to replace artificial graphite in organic electrolyte with different film-forming additives

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Chinese Journal of Chemical Engineering 2023年第4期56卷 58-69页

作者： Shaojun niu Guobin Zhu kai Wu Honghe Zheng College of Energy Soochow UniversitySuzhou 215006China Contemporary Amperex Technology Limited Ningde 352100China

The feasibility for natural graphite(NG)to replace artificial graphite(AG)in organic electrolytes with different additives are *** the strong film-forming additives contributes to form robust solid electrolyte interphase(SEI)film on graphite particle surface,great differences in gas evolution,lithium inventory loss and other side reactions are *** bis(oxalato)borate(Li BOB)and fluoroethylene carbonate(FEC)are found more effective and the combination shows to be more *** the optimized electrolyte,natural graphite anode exhibits excellent long-term cycling *** 800 cycles at high temperature,the capacity retention is comparable to that using artificial *** mechanisms for the capacity-fading of the full cells with AG and NG anode are investigated by ICP,SEM and polarization *** results shows that NG electrode consumes more active lithium due to the rough surface and larger volume *** rapid capacity-fading in the initial 100 cycles is related to the instability of the SEI film aroused from large volume *** systematic analysis is inspiriting for the development of high performance lithium ion batteries with reduced cost.

关键词： Lithium ion batteries Natural graphite Electrolyte additive Solid electrolyte interphase