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FAST Observations of an Extremely Active Episode of FRB 20201124A.Ⅳ.Spin Period Search

Research in Astronomy and Astrophysics 2022年第12期22卷 99-122页

作者： Jia-rui Niu Wei-Wei Zhu Bing Zhang Mao Yuan De-Jiang Zhou Yong-Kun Zhang Jin-Chen Jiang J.L.Han Di li Ke-Jia Lee Pei Wang Yi feng Dong-Zi li rui Luo Fa-Yin Wang Zi-Gao Dai Chen-Chen Miao Chen-Hui Niu Heng Xu Chun-feng Zhang Wei-Yang Wang Bo-Jun Wang Jiang-Wei Xu National Astronomical Observatories Chinese Academy of SciencesBeijing 100101China University of Chinese Academy of Sciences Beijing 100049China Institute for Frontier in Astronomy and Astrophysics Beijing Normal UniversityBeijing 102206China Department of Physics and Astronomy University of NevadaLas VegasNV 89154USA Department of Astronomy Peking UniversityBeijing 100871China NAOC-UKZN Computational Astrophysics Centre University of KwaZulu-NatalDurban 4000South Africa Kavli Institute for Astronomy and Astrophysics Peking UniversityBeijing 100871China Research Center for Intelligent Computing Platforms Zhejiang LaboratoryHangzhou 311100China Cahill Center for Astronomy and Astrophysics MC 249-17 California Institute of TechnologyPasadena CA 91125USA CSIRO Space and Astronomy PO Box 76EppingNSW 1710Australia School of Astronomy and Space Science Nanjing UniversityNanjing 210093China Key Laboratory of Modern Astronomy and Astrophysics Nanjing UniversityMinistry of EducationNanjing 210093China Department of Astronomy University of Science and Technology of ChinaHefei 230026China

We report the properties of more than 800 bursts detected from the repeating fast radio burst(FRB)source FRB 20201124A with the Five-hundred-meter Aperture Spherical radio Telescope during an extremely active episode on UTC 2021 September 25th-28th in a series of four *** this fourth paper of the series,we present a systematic search of the spin period and linear acceleration of the source object from both 996 individual pulse peaks and the dedispersed time *** credible spin period was found from this data *** rule out the presence of significant periodicity in the range between 1 ms and 100 s with a pulse duty cyclelinear acceleration up to 300 m s^(-2)in each of the four one-hour observing sessions,and up to 0.6 m s^(-2)in all 4 *** searches contest theoretical scenarios involving a 1 ms–100 s isolated magnetar/pulsar with surface magnetic field10 *** also perform a periodicity search of the fine structures and identify 53 unrelated millisecond-timescale“periods”in multicomponents with the highest significance of 3.9σ.The“periods”recovered from the fine structures are neither consistent nor harmonically *** they are not likely to come from a spin *** caution against claiming spin periodicity with significance below~4σwith multi-components from one-off *** discuss the implications of our results and the possible connections between FRB multi-components and pulsar microstructures.

关键词： pulsars:general methods:observational radio continuum:general

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Estimation of Age,Growth and Maturation of Purpleback Flying Squid,Sthenoteuthis oualaniensis,in Bashi Channel,Central Pacific Ocean

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Journal of Ocean University of China 2017年第3期16卷 525-531页

作者： liU Bilin liN Jingyuan feng Chunlei li Jianhua SU Hang College of Marine Sciences Shanghai Ocean University East China Sea Fisheries Research Institute Chinese Academy of Fishery Sciences

The age, growth and maturation of Sthenoteuthis oualaniensis were determined with statolith data collected with a light purse seine from the Bashi Channel of central Pacific Ocean. The estimated longevity of the squid was no more than 6 months for females, and no more than 5 months for males. Growth in mantle length(ML) was best described by logistic models for both females and males, while growth in body weight(BW) was best fitted by power curves. The maximum absolute growth rate(AGR) and instantaneous growth rate(IGR) in ML or BW both occurred at 91–105 days for females and 76–90 days for males. Back calculated hatching dates were from October to January, with a peak in December, although the short duration of sampling date might have had an influence on the result. The lower percentage of mature females(37.2%) suggested that the study area during the sampling date was not a spawning ground for the species. Size and age at first maturity were 183 mm ML and 136 days for females, whereas they were 156 mm ML and 85 days for males.

关键词： Sthenoteuthis oualaniensis central Pacific Ocean statolith age growth maturation

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Conversion of Benzene in the Catalytic Cracking Process

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China Petroleum Processing & Petrochemical Technology 2022年第3期24卷 77-85页

作者： li rui Yan Jiasong Geng Qiuyue Chen Hui Su Youyou Wang Yongchao SINOPEC Research Institute of Petroleum Processing Co. Ltd.Beijing 100083China Wuhan Jinsinopec Petrochemical Engineering Co. Ltd.Wuhan 430223China College of Chemistry and Chemical Engineering Xiamen UniversityXiamen 361005China lier Chemical Co. Ltd.Chengdu 610052China

The catalytic cracking of 1-hexene,1-heptene,1-octene,1-nonene,1-decene,and five olefins mixed with benzene,over USY catalysts was conducted in a small fixed fluidized bed reactor to study the conversion of benzene under catalytic cracking *** mainly alkylated with C_(2)-C_(5)light olefins,generating monosubstituted alkylbenzenes,and the concentration of light olefins dramatically affected the alkylbenzene *** to the limitation of thermodynamic equilibrium,the yield of benzene alkylation to alkylbenzene in catalytic cracking was in a relative low *** equilibrium constant of benzene alkylation decreases with the increasing reaction temperature which resulted in reduction of alkyl benzene yield.

关键词： alkylbenzene benzene catalytic cracking cracking catalyst olefin

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Synthetic process and spark plasma sintering of SrIrO_(3) composite oxide

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Journal of Advanced Ceramics 2013年第4期2卷 347-352页

作者： Yongshang TIAN Yansheng GONG Zhaoying li feng JIANG Hongyun JIN Faculty of Material Science and Chemistry China University of GeosciencesWuhan 430074People’s Republic of China Engineering Research Center and Application of Nano-Geomaterials of Ministry of Education China University of GeosciencesWuhan 430074People’s Republic of China

Single phase of SrIrO_(3) powders and ceramics were obtained by solid-state chemical reaction method and spark plasma sintering(SPS)technique,*** evolutions,characteristics,morphology and resistivity of the samples were studied by using thermogravimetric analysis-differential scanning calorimetry(TG-DSC),X-ray diffractometry(XRD),field emission scanning electron microscopy(FESEM)and four-point probe method,*** results showed that the reaction process to form SrIrO_(3) phase occurred between SrCO_(3) and IrO_(2) directly during the heating *** using optimum fabrication conditions established from the TG-DSC results,single phase of SrIrO_(3) powders was synthesized at 800-1000℃.SrIrO_(3) ceramics were sintered by SPS technique at 1000-1100℃with a pressure of 30 MPa,showing a high relative density of 92%-96%and dense *** room-temperature resistivity of SrIrO_(3) ceramics was about 2×10^(-4)Ω×*** present study can provide high-quality ceramic target for the preparation of SrIrO_(3) films in traditional physical vapor deposition(PVD)method.

关键词： SrIrO_(3) powder controllable synthesis spark plasma sintering(SPS)

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A Positivity-preserving Conservative Semi-Lagrangian Multi-moment Global Transport Model on the Cubed Sphere

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Advances in Atmospheric Sciences 2021年第9期38卷 1460-1473页

作者： Jie TANG Chungang CHEN Xueshun SHEN feng XIAO Xingliang li National Meteorological Center/Center of Numerical Weather Predication China Meteorological AdministrationBeijing 100081China State Key Laboratory for Strength and Vibration of Mechanical Structures&School of Aerospace Engineering Xi’an Jiaotong UniversityXi’an 710049China Department of Mechanical Engineering Tokyo Institute of TechnologyTokyo 152-8850Japan

A positivity-preserving conservative semi-Lagrangian transport model by multi-moment finite volume method has been developed on the cubed-sphere *** kinds of moments(i.e.,point values(PV moment) at cell interfaces and volume integrated average(VIA moment) value) are defined within a single *** PV moment is updated by a conventional semi-Lagrangian method,while the VIA moment is cast by the flux form formulation to assure the exact numerical *** from the spatial approximation used in the CSL2(conservative semi-Lagrangian scheme with second order polynomial function) scheme,a monotonic rational function which can effectively remove non-physical oscillations is reconstructed within a single cell by the PV moments and VIA *** achieve exactly positive-definite preserving,two kinds of corrections are made on the original conservative semi-Lagrangian with rational function(CSLR)*** resulting scheme is inherently conservative,non-negative,and allows a Courant number larger than ***,the spatial reconstruction can be performed within a single cell,which is very efficient and economical for practical *** addition,a dimension-splitting approach coupled with multi-moment finite volume scheme is adopted on cubed-sphere geometry,which benefitsthe implementation of the 1 D CSLR solver with large Courant *** proposed model is evaluated by several widely used benchmark tests on cubed-sphere *** results show that the proposed transport model can effectively remove nonphysical oscillations and preserve the numerical nonnegativity,and it has the potential to transport the tracers accurately in a real atmospheric model.

关键词： global transport model cubed-sphere grid multi-moment method single-cell-based scheme conservative semi-Lagrangian method

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Stiffness Degradation Characteristics Destructive Testing and Finite-Element Analysis of Prestressed Concrete T-Beam

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Computer Modeling in Engineering & Sciences 2018年第1期114卷 75-93页

作者： Chengquan Wang Yonggang Shen Yun Zou Tianqi li Xiaoping feng School of Environment and Civil Engineering Jiangnan UniversityWuxiChina214122 College of Civil Engineering and Architecture Zhejiang UniversityHangzhouChina310058

The failure behavior of the precast prestressed concrete T girder was investigated by destructive test and finite-element analysis,and the mid-span deflection,girder stiffness and the variation of the cross section strain in the loading process were obtained,and the mechanical properties,mechanical behavior,elastic and plastic behavior and ultimate bearing capacity of T girder with large span were ***,the relationship between the beam stiffness degradation,the neutral axis in cross-section,steel yielding and concrete cracking are investigated and analyzed.A method was proposed to predict the residual bearing capacity of a bridge based on the variation of the position of the cross section strain distribution and the section neutral axis,which provided a theoretical basis for predicting the stiffness detection and carrying capacity assessment of prestressed concrete beam.

关键词： Prestressed concrete T-beam destructive testing finite-element stiffness plane-section assumption

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Effects of Integrated Soil-Crop System Management on Soil Organic Carbon Characteristics in a Primosol in Northeast China

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Pedosphere 2017年第5期27卷 957-967页

作者： ZHANG Jinjing CAO Zhiyuan feng Guozhong li Mengyao li Cuilan GAO Qiang WANG lichun Key Laboratory of Soil Resource Sustainable Utilization for Jilin Province Commodity Grain Bases College of Resource and Environmental ScienceJilin Agricultural University Institute of Agricultural Resources and Environments Jilin Academy of Agricultural Sciences

A synchronous increase in crop productivity, nutrient use efficiency, and soil carbon(C) sequestration is important from the point of view of food security and environmental protection. In recent years, integrated soil-crop system management(ISSM), which uses crop models and advanced nutrient management to redesign cropping systems, has been successfully demonstrated to achieve both high crop productivity and high nutrient use efficiency in China, but the effects of ISSM on soil organic C(SOC) characteristics remain unknown. In this study, the effects of current farmers' practice(FP), high-yielding practice(HY), which maximizes yields without considering costs, and ISSM on the content and chemical composition of SOC were studied in a 4-year(2009–2013) field plot experiment with maize(Zea mays L.) monoculture in an Alluvic Primosol in Northeast China. The ISSM resulted in higher soil total organic C(TOC), water-soluble organic C, easily-oxidizable organic C, particulate organic C, and humic acid C compared with HY and FP in the region. The SOC contents in aggregate size fractions generally followed a similar pattern to TOC. Compared with FP,HY decreased the mean weight diameter, geometric mean diameter, percentage of > 0.25-mm water-stable aggregates, and the stability ratio of water-stable aggregates, and increased the structure-deterioration rate and index of unstable aggregates. The opposite trend was observed between ISSM and HY. Solid-state ^(13)C nuclear magnetic resonance spectra of bulk soil showed that ISSM had higher O-alkyl C and aliphatic C/aromatic C ratio, but lower aromatic C, carbonyl C, and alkyl C/O-alkyl C and hydrophobic C/hydrophilic C ratios than HY and FP. Our results suggest that ISSM improves the quantity and quality of SOC and has a positive effect on soil aggregation and aggregate stability.

关键词： aggregate size fractions maize grain yield nutrient use efficiency soil aggregates solid-state ]3C nuclear magneticresonance

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Conversion characteristics and mechanism analysis of gaseous dichloromethane degraded by a VUV light in different reaction media

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Journal of Environmental Sciences 2012年第10期24卷 1777-1784页

作者： Jianming Yu Wenji Cai Jianmeng Chen li feng Yifeng Jiang Zhuowei Cheng .College of Biological and Environmental Engineering Zhefiang University of Technology Hangzhou 310032 China Environmental Science and Engineering Research Institute Zhefiang University of Technology Hangzhou 310032 China

The photodegradation of gaseous dichloromethane （DCM） by a vacuum ultraviolet （VUV） light in a spiral reactor was investigated with different reaction media and initial concentrations. Through the combination of direct photolysis, O3 oxidation and HO. oxidation, DCM was ultimately mineralized into inorganic compounds （such as HC1, CO2, H20, etc.） in the air with relative humidity （RH） of 75%-85%. During the photodegradation process, some small organic acids （including formic acid, acetic acid） were also detected and the intermediates were more soluble than DCM, providing a possibility for its combination with subsequent biodegradation. Based on the detected intermediates and the confirmed radicals, a photodegradation pathway of DCM by VUV was proposed. With RH 75%- 80% air as the reaction medium, the DCM removal followed the second-order kinetic model at inlet concentration of 100-1000 mg/m3. Kinetic analysis showed that the reaction media affected the kinetic constants of DCM conversion by a large extent, and RH 80% air could cause a much lower half-life for its conversion. Such results supported the possibility that VUV photodegradation could be used not only for the mineralization of DCM but also as a pretreatment before biodegradation.

关键词： dichloromethane VUV photodegradation mechanism carbon balance kinetic analysis

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Experimental and numerical investigation of threedimensional vortex structures of a pitching airfoil at a transitional Reynolds number

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Chinese Journal of Aeronautics 2019年第10期32卷 2254-2266页

作者： Zhenyao li lihao feng Hamid Reza KARBASIAN Jinjun WANG Kyung Chun KIM Fluid Mechanics Key Laboratory of Education Ministry Beihang UniversityBeijing 100083China School of Mechanical Engineering Pusan National UniversityBusan 46241Republic of Korea

This research examines the vortex behaviors and aerodynamic forces in dynamic stall phenomena at a transitional Reynolds number(Re=90000)using experimental and numerical *** sinusoidal pitching motion at two different reduced frequencies is used to achieve the dynamic stall of a NACA 0012 *** leading edge vortices form and detach in the dynamic stall *** flow then quickly transitions to a full separation zone in the stall stage when the angle of attack starts to *** is discrepancy between the phaseaveraged and instantaneous flow field in that the small flow structures increased with angle of attack,which is a characteristic of the flow field at the transitional Reynolds *** interaction between the streamwise vortices in the three-dimensional numerical results and the leading edge vortex are the main contribution to the turbulent *** addition,the leading edge vortex that supplies vortex lift is more stable at higher reduced frequency,which decreases the lift fluctuation in the dynamic stall *** leading edge vortex at higher reduced frequency is strong enough to stabilize the flow,even when the airfoil is in the down-stroke phase.

关键词： DDES Dynamic stall Pitching airfoil PIV Transitional Reynolds number

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liver Stiffness Measurement can Predict liver Inflammation in Chronic Hepatitis B Patients with Normal Alanine Transaminase

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Journal of Clinical and Translational Hepatology 2023年第4期11卷 817-826页

作者： ling-ling Huang Xue-Ping Yu Qing-Fa Ruan Yan-Xue lin Huan li Wen Jin rui-feng liu Yan-Lan liang Yu-rui liu Yue-Yong Zhu Jia-Ji Jiang Ri-Cheng Mao Da-Wu Zeng Department of Hepatology Hepatology Research InstituteThe First Affiliated hospitalFujian Medical UniversityFuzhouFujianChina Department of Infectious Diseases The First Hospital of Quanzhou Affiliated to Fujian Medical UniversityQuanzhouFujianChina Hepatology Center Xiamen Hospital of Traditional Chinese MedicineXiamenFujianChina Department of Infectious Diseases Shanghai Key Laboratory of Infectious Diseases and Biosafety Emergency ResponseNational Medical Center for Infectious DiseasesHuashan HospitalFudan UniversityShanghaiChina Hepatology Mengchao Hepatobiliary Hospital of Fujian Medical UniversityFuzhouFujianChina Hepatology Fujian Medical University Xiamen Humanity HospitalXiamenFujianChina

Background and Aims:To determine whether liver stiffness measurement(LSM)indicates liver inflammation in chronic hepatitis B(CHB)with different upper limits of normal(ULNs)for alanine aminotransferase(ALT).Methods:We grouped 439 CHB patients using different ULNs for ALT:cohort I,≤40 U/L(439 subjects);cohort II,≤35/25 U/L(males/females;330 subjects);and cohort III,≤30/19 U/L(males/females;231 subjects).Furthermore,84 and 96 CHB patients with normal ALT(≤40 U/L)formed the external and prospective validation groups,respectively We evaluated the correlation between LSM and biopsy-confirmed liver inflammation,and determined diagnostic accuracy using area under the curve(AUC).A noninvasive LSM-based model was developed using multivariate logistic ***:Fibrosis-adjusted LSM values significantly increased with increasing *** AUCs of LSM in cohorts I,II,and III were 0.799,0.796,and 0.814,respectively,for significant inflammation(A≥2)and 0.779,0.767,and 0.770,respectively,for severe inflammation(A=3).Cutoff LSM values in all cohorts for A≥2and A=3 were 6.3 and 7.5 kPa,***,external,and prospective validations showed high diagnostic accuracy of LSM for A≥2 and A=3,and no significant differences in AUCs among the four *** and globulin independently predicted A≥*** AUC of an LSM-globulin model for A≥2 exceeded those of globulin,ALT,and AST,but was similar to that of ***:LSM predicted liver inflammation and guided the indication of antiviral therapy for CHB in patients with normal ALT.

关键词： Hepatitis B virus liver inflammation Fibrosis liver stiffness measurement Alanine aminotransferase

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