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Semi-analytical assessment of the relative accuracy of the GNSS/INS in railway track irregularity measurements

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Satellite Navigation 2021年第1期2卷 352-367页

作者： qijin chen Quan Zhang Xiaoji Niu Jingnan Liu GNSS Research Center Wuhan UniversityWuhanChina Collaborative Innovation Center of Geospatial Technology Wuhan UniversityWuhanChina Artificial Intelligence Institute Wuhan UniversityWuhanChina.

An aided Inertial Navigation System(INS)is increasingly exploited in precise engineering surveying,such as railway track irregularity measurement,where a high relative measurement accuracy rather than absolute accuracy is ***,how to evaluate the relative measurement accuracy of the aided INS has rarely been *** address this problem with a semi-analytical method to analyze the relative measurement error propagation of the Global Navigation Satellite System(GNSS)and INS integrated system,specifically for the railway track irregularity measurement *** GNSS/INS integration in this application is simplified as a linear time-invariant stochastic system driven only by white Gaussian noise,and an analytical solution for the navigation errors in the Laplace domain is obtained by analyzing the resulting steady-state Kalman ***,a time series of the error is obtained through a subsequent Monte Carlo simulation based on the derived error propagation *** proposed analysis method is then validated through data simulation and field *** results indicate that a 1 mm accuracy in measuring the track irregularity is achievable for the GNSS/INS integrated ***,the influences of the dominant inertial sensor errors on the final measurement accuracy are analyzed quantitatively and discussed comprehensively.

关键词： Inertial surveying Relative measurement accuracy Error propagation modeling Steady-state Kalman filter Precise engineering surveying

Ultra high temperature superfluidity in ultracold atomic Fermi gases with mixed dimensionality

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Science China(Physics,Mechanics & Astronomy) 2020年第2期63卷 142-145页

作者： Leifeng Zhang Jibiao Wang Yi Yu qijin chen Department of Physics and Zhejiang Institute of Modern Physics Zhejiang UniversityHangzhou 310027China Laboratory of Quantum Engineering and Quantum Metrology School of Physics and AstronomySun Yat-Sen University(Zhuhai Campus)Zhuhai 519082China College of Chemical Engineering Zhejiang University of TechnologyHangzhou 310014China Synergetic Innovation Center of Quantum Information and Quantum Physics Hefei 230026China

It has been an important goal to achieve higher or even room temperature superconductivity,since the discovery of high Tc superconductors in 1986,with a typical maximum transition temperature Tc of around 95 K at ambien pressure[1]or up to 164 K for the Hg-based cuprates under high pressure[2].The typical Tc/TF is only around 0.05 or less,where TF denotes the Fermi *** have been a few other families of superconductors,including the iron-based[3],heavy fermion[4]and organic superconductors[5].Their maximum attainable Tc/TF has not been able to exceed that of the *** notable superconductors include the recently discovered H2S with a record high Tc=203 K under an enormous high pressure of 90 GPa[6],and the monolayer FeSe/SrTiO3 superconductors with a gap opening temperature up to 100 K[7].

关键词： temperature. superconductors Fermi

Unusual Destruction and Enhancement of Superfluidity of Atomic Fermi Gases by Population Imbalance in a One-Dimensional Optical Lattice

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Chinese Physics Letters 2020年第5期37卷 42-46页

作者： qijin chen Jibiao Wang Lin Sun Yi Yu Simnghaj Branch National Laboratory for Physical Sciences at Microscale and Department of Modern PhysicsUniversity of Science and Technology of ChinaShanghai 201315 Department of Physics and Zhejiang Institute of Modern Physics Zhejiang UniversityHangzhou 310027 Synergetic Innovation Center of Quantum Information and Quantum Physics Hefei 230026 Laboratory of Quantum Engineering and Quantum Metrology School of Physics and AstronomySun Yat-Sen University(Zhuhai Campus)Zhuhai 519082 College of Chemical Engineering Zhejiang University of TechnologyHangzhou 310014

We study the superfluid behavior of a population imbalanced ultracold atomic Fermi gases with a short range attractive interaction in a one-dimensional(1D)optical lattice,using a pairing fluctuation *** show that,besides widespread pseudogap phenomena and intermediate temperature superfluidity,the superfluid phase is readily destroyed except in a limited region of the parameter *** find a new mechanism for pair hopping,assisted by the excessive majority fermions,in the presence of continuum-lattice mixing,which leads to an unusual constant Bose-Einstein condensate(BEC)asymptote for Tc that is independent of pairing *** result,on the BEC side of unitarity,superfluidity,when it exists,may be strongly enhanced by population imbalance.

关键词： theory. Fermi usual

Observation of the density dependence of the closed-channel fraction of a 6Li superfluid

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National Science Review 2022年第10期9卷 105-111页

作者： Xiang-Pei Liu Xing-Can Yao Hao-Ze chen Xiao-Qiong Wang Yu-Xuan Wang Yu-Ao chen qijin chen Kathryn Levin Jian-Wei Pan Hefei National Laboratory for Physical Sciences at the Microscale and Department of Modern Physics University of Science and Technology of China Shanghai Branch CAS Center for Excellence in Quantum Information and Quantum Physics University of Science and Technology of China Shanghai Research Center for Quantum Sciences James Franck Institute University of Chicago

Atomic Fermi gases provide an ideal platform for studying pairing and superfluid physics,using a Feshbach resonance between closed-channel molecular states and open-channel scattering *** particular interest is the strongly interacting *** show that the closed-channel fraction Zccprovides an effective probe for important many-body interacting effects,especially through its density dependence,which is absent from two-body theoretical *** we measure Zccas a function of interaction strength and the Fermi temperature TF in a trapped 6Li superfluid throughout the entire Bardeen-Cooper-Schrieffer-Bose-Einstein-condensate crossover,in quantitative agreement with theory when important thermal contributions outside the superfluid core are taken into *** from the deep-BEC regime,the fraction Zccis sensitive to *** particular,our data show Zcc∝TFαwith α=1/2at unitarity,in quantitative agreement with calculations of a two-channel pairing fluctuation theory,and a increases rapidly into the BCS regime,reflecting many-body interaction effects as predicted.

关键词： closed-channel fraction density dependence strongly interacting Fermi gas many-body effect

Coexistence of nontrivial topological properties and strong ferromagnetic fluctuations in quasi-one-dimensional A_(2)Cr_(3)As_(3)

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npj Computational Materials 2020年第1期6卷 1413-1420页

作者： chenchao Xu Ninghua Wu Guo-Xiang Zhi Bing-Hua Lei Xu Duan Fanlong Ning Chao Cao qijin chen Department of Physics Zhejiang University310027 HangzhouChina CAS Key Laboratory of Functional Materials and Devices for Special Environments Xinjiang Technical Institute of Physics and ChemistryCASXinjiang Key Laboratory of Electronic Information Materials and Devices40-1 South Beijing Road830011 UrumqiChina Condensed Matter Group Department of PhysicsHangzhou Normal University311121 HangzhouChina Westlake University HangzhouZhejiangChina Department of Physics Fudan UniversityShanghaiChina Collaborative Innovation Center of Advanced Microstructures Nanjing University210093 NanjingChina Shanghai Branch National Laboratory for Physical Sciences at Microscale and Department of Modern PhysicsUniversity of Science and Technology of China201315 ShanghaiChina

Superconductivity in crystals without inversion symmetry has received extensive attention due to its unconventional pairing and possible nontrivial topological *** first-principles calculations,we systemically study t... 详细信息

关键词： properties nontrivial topological

Genome sequencing and analysis of a granulovirus isolated from the Asiatic rice leafroller, Cnaphalocrocis medinalis

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Virologica Sinica 2015年第6期30卷 417-424页

作者： Shan Zhang Zheng Zhu Shifeng Sun qijin chen Fei Deng Kai Yang State Key Laboratory of Biocontrol Sun Yat-sen University State Key Laboratory of Virology and China Center for Virus Culture Collection Wuhan Institute of Virology Chinese Academy of Sciences Guangdong Haina Agriculture Co. Ltd

The complete genome of Cnaphalocrocis medinalis granulovirus(CnmeGV) from a serious migratory rice pest, Cnaphalocrocis medinalis(Lepidoptera: Pyralidae), was sequenced using the Roche 454 Genome Sequencer FLX system(GS FLX) with shotgun strategy and assembled by Roche GS De Novo assembler software. Its circular double-stranded genome is 111,246 bp in size with a high A+T content of 64.8% and codes for 118 putative open reading frames(ORFs). It contains 37 conserved baculovirus core ORFs, 13 unique ORFs, 26 ORFs that were found in all Lepidoptera baculoviruses and 42 common ORFs. The analysis of nucleotide sequence repeats revealed that the CnmeGV genome differs from the rest of sequenced GVs by a 23 kb and a 17 kb gene block inversions, and does not contain any typical homologous region(hr) except for a region of non-hr-like sequence. Chitinase and cathepsin genes, which are reported to have major roles in the liquefaction of the hosts, were not found in the CnmeGV genome, which explains why CnmeGV infected insects do not show the phenotype of typical liquefaction. Phylogenetic analysis,based on the 37 core baculovirus genes, indicates that CnmeGV is closely related to Adoxophyes orana granulovirus. The genome analysis would contribute to the functional research of CnmeGV,and would benefit to the utilization of CnmeGV as pest control reagent for rice production.

关键词： baculovirus granulovirus Cnaphalocrocis medinalis granulovirus(CnmeGV) genome sequencing

风险偏好对个体收入的影响--来自中国城镇劳动力市场的证据

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南方经济 2015年第8期44卷 92-106页

作者：陈其进重庆工商大学财政金融学院 400067

传统收入理论一直忽视了一个重要的因素——风险偏好。基于2009年农村—城市移民调查数据(RUMIC2009),本文考察了风险偏好对个体收入的影响。实证结果表明,风险偏好对个体收入有显著正向影响,且对城镇居民的影响大于农民工;风险偏好对... 详细信息

传统收入理论一直忽视了一个重要的因素——风险偏好。基于2009年农村—城市移民调查数据(RUMIC2009),本文考察了风险偏好对个体收入的影响。实证结果表明,风险偏好对个体收入有显著正向影响,且对城镇居民的影响大于农民工;风险偏好对创业者和工资获得者收入均有显著正向影响,不过对城镇居民创业者收入作用不显著;此外,风险偏好对女性收入的影响在城镇居民中大于男性,在农民工中稍小于男性。风险偏好对过低的年龄组群体收入没有显著影响,且随着年龄的提升,风险偏好对个体收入的作用也逐渐增强。采用父母的风险偏好作为工具变量,纠正可能的内生性问题后,风险偏好对个体收入的正向影响仍然存在。

关键词：风险偏好收入城镇居民农民工

风险偏好对创业选择的异质性影响--基于RUMIC 2009数据的实证研究

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人口与经济 2015年第2期 78-86页

作者：陈其进南开大学经济学院天津300071

风险偏好对经济增长的重要引擎——创业的影响如何?本文基于2009年的农村—城市移民调查数据(RUMIC 2009)中的城镇居民住户调查(UHS)和农民工住户调查(MHS),研究了风险偏好对创业选择在性别与教育上的异质性影响。结果发现,总体上,风险... 详细信息

风险偏好对经济增长的重要引擎——创业的影响如何?本文基于2009年的农村—城市移民调查数据(RUMIC 2009)中的城镇居民住户调查(UHS)和农民工住户调查(MHS),研究了风险偏好对创业选择在性别与教育上的异质性影响。结果发现,总体上,风险偏好度显著提高创业概率,但只对男性、文化程度为小学及以下、初中、大专学历的群体有显著影响,而对女性和其他学历的群体均没有显著影响;只有在风险偏好度提升较大时,影响才显著,并且提升越大,影响越大。因此,政策制定者应对不同性别和教育水平的群体设计不同的创业促进措施。

关键词：风险态度创业性别教育

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基于轨道不平顺匹配的多源融合列车定位方法

哈尔滨工程大学学报 2024年第7期45卷 1358-1366页

作者：周禹昆陈起金牛小骥武汉大学卫星导航定位技术研究中心湖北武汉430000

列车定位是保障铁路安全高效运营的基础,面向先进列车运行控制系统高精度、连续、可靠的位置服务需求,研究高精度、高可靠、低成本的匹配定位源提升列车定位系统的稳健性和准确度具有重要的现实意义。本文提出一种无布设轨道特征信号-... 详细信息

列车定位是保障铁路安全高效运营的基础,面向先进列车运行控制系统高精度、连续、可靠的位置服务需求,研究高精度、高可靠、低成本的匹配定位源提升列车定位系统的稳健性和准确度具有重要的现实意义。本文提出一种无布设轨道特征信号-轨道不平顺,利用惯性导航系统感知和测量轨道不平顺信号实现匹配定位,结合列车运动约束,实现了无布设情况下的全自主、全天候、全地域的连续可靠的组合定位。为了验证该方案的可行性,本文在真实铁路线路上进行了列车车载试验。试验结果表明:一个典型的战术级IMU可以实现0.6 m(98.46%置信度)的列车定位精度。该方法为多传感器融合的列车定位系统提供了一种新的定位信号源,可以用于提高车载列车定位系统的准确性和稳健性。

关键词：列车定位轨道不平顺特征匹配车载传感器定位系统惯性导航系统组合导航多源融合列车运动约束

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