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Communications in Theoretical Physics 2018年第9期69卷 331-336页

作者： chun-hui zhang chun-Mei zhang Qin Wang Institute of Signal Processing Transmission Nanjing University of Posts and TelecommunicationsNanjing 210003China Key Lab of Broadband Wireless Communication and Sensor Network TechnologyNanjing University of Posts and TelecommunicationsMinistry of EducationNanjing 210003China

Statistical fluctuations are unavoidable in realistic quantum key distribution (QKD) due to finite-size effect. Based on the four-intensity proposal on measurement-device-independent QKD (MDI-QKD) in [Phys. Rev. A93 (2016) 042324], we particularly analyze the scenario that only three intensities are used, namely a three-intensity decoy-state MDI-QKD with biased basis choice. After performing full parameter optimization method, simulations results demonstrate that this scenario can obtain distinct enhancement compared with the conventional unbiased threeintensity decoy-state method, e.g. Xu et al.’s [Phys. Rev. A 89 (2014) 052333]. Furthermore, results also show that it works more efficiently by using HSPS than using WCS at longer transmission distance.

关键词： measurement-device-independent quantum key distribution statistical fluctuations biased basis choice

Quantitative gradient estimates for harmonic maps into singular spaces

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Science China Mathematics 2019年第11期62卷 2371-2400页

作者： hui-chun zhang Xiao Zhong Xi-Ping Zhu Department of Mathematics Sun Yat-sen UniversityGuangzhou 510275China Department of Mathematics and Statistics University of HelsinkiHelsinki F7-00014Finland

In this paper, we show the Yau’s gradient estimate for harmonic maps into a metric space(X, dX)with curvature bounded above by a constant κ(κ 0) in the sense of Alexandrov. As a direct application,it gives some Liouville theorems for such harmonic maps. This extends the works of Cheng(1980) and Choi(1982) to harmonic maps into singular spaces.

关键词： harmonic maps Bochner formula CAT(κ)-spaces Liouville theorem

Modeling of LF refining process:a review

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Journal of Iron and Steel Research International 2024年第2期31卷 289-317页

作者： Zi-cheng Xin Jiang-shan zhang Kai-xiang Peng Jun-guo zhang chun-hui zhang Qing Liu State Key Laboratory of Advanced Metallurgy University of Science and Technology BeijingBeijing100083China School of Automation and Electrical Engineering University of Science and Technology BeijingBeijing100083China Tangshan Branch Hebei Iron and Steel Co.Ltd.Tangshan063000HebeiChina Xinjiang Bayi Iron and Steel Co. Ltd.Baosteel GroupWulumuqi830022XinjiangChina

With the increasing demand for energy conservation and emission reduction,more attentions have been paid to the intelligentization,greenization and low carbonization during the transformation and upgrading of steelmaking *** furnace(LF)refining is one of the key procedures in steelmaking process and has been widely used in steelmaking plants for its high equipment matching degree,low equipment investment and outstanding refining *** to the main tasks of LF refining process,the modeling methods of temperature prediction model,slag-making model,alloying model,argon blowing model and model of inclusions behavior were systematically reviewed,and the advantages and disadvantages of each modeling method were *** addition,the technical framework for the future has also been proposed based on existing works,including classification of raw materials,graphic representation of knowledge,introduction,upgradation and management of device/equipment,customization of steelmaking,modeling of refining process,synergy of models,intelligentization of decision-making,automation of control,and digitization of processes and operations,aiming to provide a reference for the modeling and intelligent development of LF refining process.

关键词： LF refining Temperature prediction Slag-making Alloying Argon blowing Inclusion behavior Modeling method

Ricci-flat Graphs with Girth Four

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Acta Mathematica Sinica,English Series 2021年第11期37卷 1679-1691页

作者： Wei Hua HE Jun LUO Chao YANG Wei YUAN hui chun zhang School of Mathematics and Statistics Guangdong University of TechnologyGuangzhou 510520P.R.China School of Mathematics Sun Yat-sen UniversityGuangzhou 510275P.R.China School of Mathematics and Statistics Guangdong University of Foreign StudiesGuangzhou 510006P.R.China

Lin-Lu-Yau introduced a notion of Ricci curvature for graphs and obtained a complete classification for all Ricci-flat graphs with girth at least *** this paper,we characterize all Ricci-flat graphs of girth four with... 详细信息

关键词： Ricci curvature Ricci-flat graph vertex-disjoint

Analytically determining frequency and amplitude of spontaneous alpha oscillation in Jansen's neural mass model using the describing function method

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Chinese Physics B 2018年第4期27卷 551-558页

作者： Yao Xu chun-hui zhang Ernst Niebur Jun-Song Wang School of Biomedical Engineering Tianjin Medical University Tianjin 300070 China Qingdao Stomatological Hospital Department of Medical Technology Equipment Qingdao 266001 China Zanvyl Krieger Mind/Brain Institute and Solomon Snyder Department of Neuroscience Johns Hopkins University Baltimore 21218 MD USA

Spontaneous alpha oscillations are a ubiquitous phenomenon in the brain and play a key role in neural information processing and various cognitive ***＇s neural mass model（NMM） was initially proposed to study the origin of alpha *** of previous studies of the spontaneous alpha oscillations in the NMM were conducted using numerical *** this study,we aim to propose an analytical approach using the describing function method to elucidate the spontaneous alpha oscillation mechanism in the ***,the sigmoid nonlinear function in the NMM is approximated by its describing function,allowing us to reformulate the NMM and derive its standard form composed of one nonlinear part and one linear ***,by conducting a theoretical analysis,we can assess whether or not the spontaneous alpha oscillation would occur in the NMM and,furthermore,accurately determine its amplitude and *** results reveal analytically that the interaction between linearity and nonlinearity of the NMM plays a key role in generating the spontaneous alpha ***,strong nonlinearity and large linear strength are required to generate the spontaneous alpha oscillations.

关键词： neural mass model spontaneous alpha oscillation describing function

Performance of passive decoy-state quantum key distribution with mismatched local detectors

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Communications in Theoretical Physics 2022年第1期74卷 40-45页

作者： Kai Yu chun-hui zhang Xing-Yu Zhou Qin Wang Institute of Quantum Information and Technology Nanjing University of Posts and TelecommunicationsNanjing 210003China Key Laboratory of Quantum Information University of Science and Technology of ChinaChinese Academy of SciencesHefei 230026China National Laboratory of Solid State Microstructures Nanjing UniversityNanjing 210093China

In quantum key distribution(QKD),the passive decoy-state method can simplify the intensity modulation and reduce some of side-channel information leakage and modulation *** is usually implemented with a heralded single-photon *** Wang et al 2016(***.A 96032312),a novel passive decoy-state method is proposed by Wang et al,which uses two local detectors to generate more detection events for tightly estimating channel ***,in the original scheme,the two local detectors are assumed to be identical,including the same detection efficiency and dark count rate,which is often not satisfied in the realistic *** this paper,we construct a model for this passive decoy-state QKD scheme with two mismatched detectors and explore the effect on QKD performance with certain *** also take the finite-size effect into consideration,showing the performance with statistical *** results show that the efficiencies of local detectors affect the key rate more obviously than dark count rates.

关键词： quantum key distribution passive decoy state heralded single-photon source detector mismatch

Improved model on asynchronous measurement-device-independent quantum key distribution with realistic devices

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Chinese Physics B 2024年第11期33卷 52-56页

作者： Mingshuo Sun chun-hui zhang Rui zhang Xing-Yu Zhou Jian Li Qin Wang Institute of Quantum Information and Technology Nanjing University of Posts and TelecommunicationsNanjing 210003China Broadband Wireless Communication and Sensor Network Technology Key Laboratory of Ministry of EducationNanjing University of Posts and TelecommunicationsNanjing 210003China Changqing Oilfield Company Digital and Intelligent Business Division China National Petroleum CorporationXi'an 710299China

In principle,the asynchronous measurement-device-independent quantum key distribution(AMDI-QKD)can surpass the key rate capacity without phase tracking and phase ***,practical imperfections in sources or detections would dramatically depress its ***,we present an improved model on AMDI-QKD to reduce the influence of these imperfections,including intensity fluctuation,the afterpulse effect,and the dead time of ***,we carry out corresponding numerical *** results show that,by implementing our present work,it can have more than 100 km longer secure transmission distance and one order of magnitude enhancement in the key generation rate after 320 km compared with the standard ***,our model can still break the Pirandola–Laurenza–Ottaviani–Banchi(PLOB)bound even under realistic experimental conditions.

关键词： asynchronous measurement-device-independent quantum key distribution intensity fluctuations afterpulse dead time

Enhanced degradation of florfenicol by microscale SiC/Fe:Dechlorination via hydrogenolysis

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Chinese Chemical Letters 2024年第7期35卷 218-221页

作者： Yun-Fei zhang chun-hui zhang Jian-hui Xu Lei Li Dan Li Jin-Hong Fan Jiale Gao Xin Quan Qi Wu Yue Zou Yan-Ling Liu Dongguan University of Technology School of Environment and Civil EngineeringDongguan 523830China State Key Laboratory of Pollution Control and Resource Reuse School of Environmental Science and EngineeringTongji UniversityShanghai 200092China

Herein,the degradation of florfenicol(FLO)over zero-valent iron(ZVI)enhanced by SiC was systematically *** was found that 5 g/L of ZVI/SiC(1:3)at pH 3.0 could completely degrade 20 mg/L of FLO within 1 h,with a Kobsvalue of 0.0873 min^(-1),12.5 times greater than that of pure ZVI(0.0069 min^(-1)).Vibrating sample magnetometer(VSM)characterizations revealed that the use of SiC supporter reduces the magnetic intensity of ZVI,which mitigates iron particle agglomeration,increases Brunauer-Emmett-Teller(BET)surface area,and enhances FLO degradation ***,ZVI/SiC exhibits a much lower hydrogen evolution potential(HEP)and significantly higher corrosion currents compared to pure *** was proposed to undergo degradation via reductive dechlorination,involving a hydrogenolysis mechanism that entails the cleavage of theσ*** study provides new insights into the reduction hydrogenation mechanism of ZVI.

关键词： Zero-valent iron Silicon carbide Reductive dechlorination Hydrogenolysis Florfenicol

Improving the purity of heralded single-photon sources through spontaneous parametric down-conversion process

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Chinese Physics B 2021年第7期30卷 63-69页

作者： Jing Wang chun-hui zhang Jing-Yang Liu Xue-Rui Qian Jian Li Qin Wang Institute of Quantum Information and Technology Nanjing University of Posts and TelecommunicationsNanjing 210003China Broadband Wireless Communication and Sensor Network Technology Key Laboratory of Ministry of EducationNanjing University of Posts and TelecommunicationsNanjing 210003China

The high-purity single-photon source plays an important role in the field of quantum ***,it is generated through spontaneous parametric down-conversion *** this paper,we investigate and summarize a few approaches on obtaining single-photon sources with a high purity using either PPKTP or PPLN nonlinear ***,we present improved schemes to increase the purity based on existing work,corresponding applicable conditions and procedures are discussed and ***,we carry out numerical simulations and show that nearly perfect purity can be reached even without using any ***,this work might provide valuable references for the generation and application of high purity single-photon sources.

关键词： quantum information quantum communication nonlinear optics

The synthesis and structural studies of mixed ligand complex,tris(1-phenyl-3-methyl-4-trifluoroacetylpyrazol-5-one)mono(1-phenyl-3-methyl-pyrazol5-one)neodymium(Ⅲ)monohydrate

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Chinese Journal of Chemistry 1990年第1期8卷 29-36页

作者： HUANG,chun-hui zhang,Shi-Wei DENG,An-Ping TANG,hui-Tong XU,Guang-Xian Department of Chemistry,Peking University,Beijing 100871 Department of Chemistry Peking University Beijing 100871

A mixed ligand neodymium complex containing 1-phenyl-3-methyl-4-trifluoroacetyl- pyrazol-5-one(HPMTFP)and 1-phenyl-3-methyl-pyrazol-5-one(PMP),with molecular formula Nd(PMTFP)_3·PMP·H_2O was *** crystal and molecular structure has been determined by single crystal X-ray diffraction *** complex crystallizes in monoclinic system with space group C_2~5h-P2_(1/n).There are four formula units in a cell of dimensions a=12.837(3),b=23.763(5),c=16.810(4) ,β=109.58(2)°.The structure has been refined by full-matrix least-squares techniques to a final R value of 0.0487 and Rw value of *** neodymium atom is coordinated to eight oxygen atoms with the average Nd-O bond length 2.439,Its thermostability,and mass spectrum have been discussed.

关键词： phenyl-3-methyl-4-trifluoroacetylpyrazol-5-one)mono phenyl-3-methyl-pyrazol5-one)neodymium monohydrate The synthesis and structural studies of mixed ligand complex,tris