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A modification of Faddeev–Popov approach free from Gribov ambiguity

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Communications in Theoretical Physics 2020年第12期72卷 137-144页

作者： Chong-yao Chen Fei Gao yu-xin Liu Department of Physics and State Key Laboratory of Nuclear Physics and Technology Peking UniversityBeijing 100871China Collaborative Innovation Center of Quantum Matter Beijing 100871China Center for High Energy Physics Peking UniversityBeijing 100871China Institut fur Theoretische Physik Universitaet HeidelbergPhilosophenweg 1669120 HeidelbergGermany

We propose a modified version of the Faddeev–Popov(FP)quantization approach for nonAbelian gauge field theory to avoid Gribov *** show that by means of introducing a new method of inserting the correct identity into the Yang–Mills generating functional and considering the identity generated by an integral through a subgroup of the gauge group,the problem of Gribov ambiguity can be removed *** by handling the absolute value of the FP determinant with the method introduced by Williams and collaborators,we lift the Jacobian determinant together with the absolute value and obtain a local *** new Lagrangian will have a nilpotent symmetry which can be viewed as an analog of the Becchi–Rouet–Stora–Tyutin symmetry.

关键词： QCD quantization scheme Gribov copy non-Abelian field theory

Statistical process monitoring based on improved principal component analysis and its application to chemical processes

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Journal of Zhejiang University-Science A(Applied Physics & Engineering) 2013年第7期14卷 520-534页

作者： Chu-dong TONG Xue-feng YAN yu-xin MA Key Laboratory of Advanced Control and Optimization for Chemical Processes of Ministry of Education East China University of Science and Technology

In this paper, a novel criterion is proposed to determine the retained principal components (PCs) that capture the dominant variability of online monitored data. The variations of PCs were calculated according to their mean and covariance changes between the modeling sample and the online monitored data. The retained PCs containing dominant variations were selected and defined as correlative PCs (CPCs). The new Hotelling's T2 statistic based on CPCs was then employed to monitor the process. Case studies on the simulated continuous stirred tank reactor and the well-known Tennessee Eastman process demonstrated the feasibility and effectiveness of the CPCs-based fault detection methods.

关键词： Fault detection Principal component analysis (PCA) Correlative principal components (CPCs) Tennessee Eastman process

A direct coupling analysis method and its application to the Scientific Research and Demonstration Platform

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Journal of Hydrodynamics 2021年第1期33卷 13-23页

作者： Jun Ding You-sheng Wu xin-yun Ni Qi-bin Wang yu-chao Chen Yong-lin Ye xin-yu Zhang yu-xiang Ma Wei-nan Yang China Ship Scientific Research Center Wuxi 214082China State Key Laboratory of Coastal and Offshore Engineering Dalian University of TechnologyDalian 116024China

Design of a very large floating structure(VLFS)deployed near islands and reefs,different from those in the open sea,inevitably faces new technical challenges including numerical analysis *** this paper,a direct coupling analysis method(DCAM)has been established based on the Boussinesq equations and the three-dimensional hydroelasisity theory with Rankine source method to analyze the responses of a VLFS in shallow sea with complicated geographical *** tests have been carried out to validate the *** further verify the numerical methods and investigate the performance of such a VLFS,a“Scientific Research and Demonstration Platform(SRDP)”was built and deployed in 2019 at the site about 1000 m off an island with water depth around 40m in South China *** is a simplified small model of a two-module semi-submersible-type *** numerical simulation of its responses on severe waves with focus on motions and connector forces is conduct by DCAM,and compared with the on-site *** agreement has been *** approves the DCAM as a feasible tool for design and safety assessment of a VLFS deployed near islands and reefs.

关键词： Very large floating structure(VLFS) hydroelastic analysis near island direct coupling analysis method model test on-site measurement verification

RF design optimization for the SHINE 3.9 GHz cavity

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Nuclear Science and Techniques 2020年第7期31卷 97-105页

作者： yu-xin Zhang Jin-Fang Chen Dong Wang Shanghai Institute of Applied Physics Chinese Academy of SciencesShanghai 201204China ShanghaiTech University Shanghai 201210China Shanghai Advanced Research Institute Chinese Academy of SciencesShanghai 201204China

The Shanghai high-repetition-rate XFEL and extreme light facility(SHINE)under construction is designed to be one of the most advanced free electron laser(FEL)facilities in the *** main part of the SHINE facility is an 8 GeV superconducting Linac operating in continuous wave(CW)*** Linac consists of seventy-five 1.3 GHz and two 3.9 GHz *** on the design and experience of 3.9 GHz cavities in the European X-ray free electron laser(E-XFEL)and the Linac coherent light source-II(LCLS-II)projects,we optimize the SHINE 3.9 GHz cavity design to adapt it for CW mode *** this paper,we present a particular redesign of the end group for the SHINE 3.9 GHz superconducting cavity that includes a redesign of the end cell and beam pipe to shift away the potentially troublesome lowest highorder modes(HOMs),a modification of the main coupler antenna,and a tuning of the HOM notch filter to meet the cavity *** losses calculations on the HOM coupler antennas show that the overheating on the inner conductor at the operating mode is diminished ***,we have also studied the HOMs to ensure there are no dangerously trapped modes in the optimized cavity design.

关键词： cavity antenna tuning

Exploring the characteristics of the flare from PMN J0218–2307 by Fermi-LAT

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Research in Astronomy and Astrophysics 2021年第7期21卷 17-22页

作者： yun-Chuan Xiang yu-Liang xin Min yuan Department of Astronomy Yunnan Universityand Key Laboratory of Astroparticle Physics of Yunnan ProvinceKunming650091China School of Physical Science and Technology Southwest Jiaotong UniversityChengdu 610031China

PMN J0218-2307(4 FGL J0218.9-2305) is classified as a blazar candidate with unknown type(BCU) in the fourth source catalog from the Fermi Large Area Telescope(Fermi-LAT).With the updated Fermi-LAT Pass 8 data,the γ-ray flaring activity toward PMN J0218-2307 is *** test statistic(TS) value of PMN J0218-2307 in energy band of 100 MeV-500 GeV is 133.893 with a significance level of 10.96σ.The maximum-likelihood photon flux is(8.131 ± 1.359) × 10^(-9) ph cm^(-2) s^(-1).A significantγ-ray flare in the period from 2008 August 4 to 2019 August 25 is found from the *** spectral characteristics of GeV energy band of PMN J0218-2307 is similar to that of flat-spectrum radio quasars(FSRQs) in the local Universe.

关键词： radiation mechanisms:non-thermal gamma rays:galaxies galaxies:active galaxies:individual(PMN J0218–2307)

Response Solutions for Degenerate Reversible Harmonic Oscillators with Zero-average Perturbation

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Acta Mathematica Sinica,English Series 2023年第10期39卷 2006-2030页

作者： xin yu GUAN Jian Guo SI Wen SI School of Statistics and Mathematics Shandong University of Finance and EconomicsJi’nan 250002P.R.China School of Mathematics Shandong UniversityJi’nan 250100P.R.China

In this paper,we consider a class of normally degenerate quasi-periodically forced reversible systems,obtained as perturbations of a set of harmonic oscillators,{x˙=y+∈f1(ωt,x,y),y˙=λx^(l)+∈f2(ωt,x,y),where 0≠λ∈R,l>1 is an integer and the corresponding involution G is(−θ,x,−y)→(θ,x,y).The existence of response solutions of the above reversible systems has already been proved in[22]if[f2(ωt,0,0)]satisfies some non-zero average conditions(See the condition(H)in[22]),here[·]denotes the average of a continuous function on T^(d).However,discussing the existence of response solutions for the above systems encounters difficulties when[f_(2)(ωt,0,0)]=0,due to a degenerate implicit function must be *** article will be doing work in this *** purpose of this paper is to consider the case where[f2(ωt,0,0)]=*** precisely,with 2p˜0(seeλ˜in(2.2))and sufficiently small,response solutions exist for eachωsatisfying a weak non-resonant condition;(2)Forλ0 and l−p is even,we prove the system admits no response solutions in most regions.

关键词： Degenerate harmonic oscillators zero-average perturbation KAM theory reversible system response solutions

Molecular test shows the color pattern is not so reliable in diagnostic of genus Dysphaea Selys(Odonata:Euphaeidae)

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Zoological Systematics 2019年第2期44卷 91-99页

作者： Yao Ji xin yu Institute of Entomology College of Life Sciences Nankai University College of Life Sciences Chongqing Normal University

A molecular study based on COI, 16S and 28S genes reveals that a batch of specimens(7 males and 4 females) of Dysphaea Selys, 1853 collected from central Vietnam,which include different color patterns of wings and body, and were originally identified as three different species, are all the same species. This study implies that, in some group of Odonata,identification only depending on color pattern may be unreliable, no matter what huge variations there are.

关键词： Odonata dragonfly wing color pattern variation molecular phylogeny

Experimental study on dynamic mechanical property of cemented tailings backfill under SHPB impact loading

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International Journal of Minerals,Metallurgy and Materials 2019年第4期26卷 404-416页

作者： yu-ye Tan xin yu Davide Elmo Lin-hui Xu Wei-dong Song Key Laboratory of High-Efficient Mining and Safety of Metal Mines (Ministry of Education of China) University of Science and Technology Beijing School of Civil and Resources Engineering University of Science and Technology Beijing Norman B.Keevil Institute of Mining Engineering Applied Science SchoolUniversity of British Columbia

Cemented tailings backfill(CTB) have increasingly been used in recent years to improve the stability of mining stopes in deep underground mines. Deep mining processes are often associated with rock bursting and high-speed dynamic loading conditions. Therefore, it is important to investigate the characteristics and dynamic mechanical behavior of CTB. This paper presents the results of dynamic tests on CTB specimens with different cement and solid contents using a split Hopkinson pressure bar(SHPB). The results showed that some CTB specimens exhibited one to two lower stress peaks after reaching dynamic peak stress before they completely failed. The greater the cement-to-tailings ratio is, the more obvious the strain reaction. This property mainly manifested as follows. First,the dynamic peak stress increased with the increase of the cement-to-tailings ratio when the impact velocity was fixed. Second, the dynamic peak stress had a quadratic relationship with the average stress rate. Third, the cement-to-tailings ratio could enhance the increase rate of dynamic peak stress with strain rate. In addition, the dynamic strength enhancement factor K increased with the increase of strain rate, and its value was larger than that of the rock samples. The failure modes of CTB specimens under low-speed impact were tensile failure and X conjugate shear failure, where were nearly the same as those under static uniaxial and triaxial compression. The CTB specimens were crushed and broken under critical strain, a failure mode similar to that of low-strength concrete. The results of the experimental research can improve the understanding of the dynamic mechanical properties of CTB and guide the strength design of deep mining backfills.

关键词： impact loading test cemented tailings backfill dynamic mechanical properties split Hopkinson pressure bar

High-Performanceα-Diimine Nickel Complexes for Facile Access of PE Elastomers with Exceptional Material Properties

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Chinese Journal of Polymer Science 2024年第5期42卷 620-635,I0008页

作者： Li-Dong Qin xin-yu Wang Qaiser Mahmood Zhi-xin yu Yi-Zhou Wang Song Zou Tong-Ling Liang Wen-Hua Sun School of Pharmaceutical Sciences Changchun University of Chinese MedicineChangchun130117China Chemistry and Chemical Engineering Guangdong Laboratory Shantou515031China Key Laboratory of Engineering Plastics and Beijing National Laboratory for Molecular Science Institute of ChemistryChinese Academy of SciencesBeijing100190China

For practicable elastomeric polyethylene,achieving high catalyst thermal stability and activity,along with precise control of polymer properties such as branching density,molecular weights,and distribution,is crucial but *** this study,two sets of symmetricalα-diimine nickel complexes,each comprising four nickel bromide or chloride complexes,were synthesized and investigated their performance for ethylene polymerization under various reaction *** activation with either Et2AlCl or MMAO cocatalysts,these complexes displayed not only high activity but also generated high molecular weight polyethylenes with controlled polydispersity and a substantial number of *** catalyst with the least steric hindrance displayed the remarkable high activity(up to 1.2×10^(7) g·mol^(-1)·h^(-1)).Notably,nickel bromides demonstrated higher activity compared to their chloride *** investigation into the effect of reaction temperature on catalytic performance revealed that NiBrMe-MMAO system displayed high thermal stability(activity up to 2.51×10^(6) g·mol^(-1)·h^(-1) at 100℃)and consistently yielded high polymer molecular weights with narrow polydispersity over a broad temperature range of 30-100℃.Of significant note,mechanical analysis of the resulting polyethylene demonstrated excellent ultimate tensile strength and high strain at ***,the polyethylene sample prepared at 100℃exhibited ultimate tensile strength up to 10 MPa with 1863%maximum strain at break and a strain recovery of up to 54.9%after ten cycles at a fixed strain of 300%,indicating excellent material properties of prepared thermoplastic polyethylene elastomers(TPE).

关键词： Thermoplastic polyethylene elastomers α-Diimine nickel pre-catalysts Ethylene polymerization Mechanical properties Highly branched polyethylene