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Avoided crossings between non-radial modes in low mass RGB stars

Research in Astronomy and Astrophysics 2012年第12期12卷 1655-1665页

作者： jun-jun guo1,2.3,{2.,2.and xiang-jun lai1,2.1 national astronomical Observatories/yunnan observatory,chinese academy of sciences, kunming 650011,china 2.Key Laboratory for the Structure and Evolution of Celestial Objects,chinese academy of sciences,kunming 650011,china 3 Graduate University of chinese academy of sciences,Beijing 100049,china national astronomical Observatories/{2. observatory Chinese Academy of Sciences Kunming 650011 China Key Laboratory for the Structure and Evolution of Celestial Objects Chinese Academy of Sciences Kunming 650011 China Graduate University of chinese academy of sciences Beijing 100049 China

Non-radial p modes and g modes appear simultaneously in red giant stars. Their frequencies have different variation rates,causing their frequencies to become close during stellar evolution so that avoided crossings *** separation between regions where acoustic waves and gravity waves propagate for l=1,2.and 3 is different,which results in the coupling efficiency also being *** present the results of numerical computations of the models we *** find that the two kinds of modes for l=2.and 3 need to be closer in frequency in order for a complete exchange to occur,compared to the case for modes with l=*** scaled oscillation frequencies also present better regularity with evolution than modes with l=1. In order to study the effect of the avoided crossings in detail,we set the mode which has the smallest mode inertia to be the p *** plot the two kinds of modes for l =1,2.and 3 in frequency and periodéchelle diagrams and find modes of l=2.and 3 fit the two relations better;they are more equally spaced in frequency and period than modes with l=*** careful observation of the two kinds oféchelle diagrams for l=2.and 3,we still find that some p modes shift a little from being equally spaced in frequency and some g modes,which are close to those p modes in period,shift a little from being equally spaced in ***,we study the relation between the deviation from period being equally spaced and the mode inertia of g modes for different *** g modes of l=1 with a period closer to the p mode have less inertia and the deviation is bigger in the periodéchelle *** deviation is also obvious. However g modes of l=2.and 3 shift a little or have almost no deviation from being equally spaced in period,even though some of them may have strong coupling and close mode inertia like in the p ***,we suggest a possible method for measuring period spacing of g modes precisely using mixed g modes with l=2.and 3 that have fewer observed mixed g m

关键词： stars:oscillations-stars:red giants

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Extending the solid solution range of sodium ferric pyrophosphate:Off‐stoichiometric Na_(3)Fe(2.5)(P_(2.O_(7))_(2.as a novel cathode for sodium‐ion batteries

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Carbon Energy 2024年第4期6卷 128-139页

作者： xiang jun Pu Kunran {2.g Zibing Pan Chunhua Song {2.g{2.g lai Renjie li Zheng‐Long Xu Zhongxue Chen Yuliang Cao Hubei Key Laboratory of Electrochemical Power Sources College of Chemistry and Molecular SciencesWuhan UniversityWuhanChina Key Laboratory of Hydraulic Machinery Transients Ministry of EducationSchool of Power and Mechanical EngineeringWuhan UniversityWuhanChina School of Chemistry and Chemical Engineering Jiangsu University of TechnologyChangzhouJiangsuChina Zonergy Corporation ZigongSichuanChina Department of Industrial and Systems Engineering The Hong Kong Polytechnic UniversityHung HomHong Kong SARChina

Iron‐based pyrophosphates are attractive cathodes for sodium‐ion batteries due to their large framework,cost‐effectiveness,and high energy ***,the understanding of the crystal structure is scarce and only a limited candidates have been reported so *** this work,we found for the first time that a continuous solid solution,Na_(4−α)Fe_(2.α)_(2.(P_(2.O_(7))_(2.(0≤α≤1,could be obtained by mutual substitution of cations at center‐symmetric Na3 and Na4 sites while keeping the crystal building blocks of anionic P_(2.O_(7) *** particular,a novel off‐stoichiometric Na_(3)Fe(2.5)(P_(2.O_(7))_(2.is thus proposed,and its structure,energy storage mechanism,and electrochemical performance are extensively investigated to unveil the structure–function *** as‐prepared off‐stoichiometric electrode delivers appealing performance with a reversible discharge capacity of 83 mAh g^(−1),a working voltage of 2.9 V(***^(+)/Na),the retention of 89.2.of the initial capacity after 500 cycles,and enhanced rate capability of 51 mAh g^(−1)at a current density of 1600 mA g^(−1).This research shows that sodium ferric pyrophosphate could form extended solid solution composition and promising phase is concealed in the range of Na_(4−α)Fe_(2.α)_(2.(P_(2.O_(7))_(2.,offering more chances for exploration of new cathode materials for the construction of high‐performance SIBs.

关键词： extending solid‐solution range off‐stoichiometric Na_(3)Fe_(2.5)(P_(2.O_(7))_(2. sodium‐ion batteries structure-function relationship

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Low-noise and low-power pixel sensor chip for gas pixel detectors

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Nuclear Science and Techniques 2024年第3期35卷 142-152页

作者： Zhuo Zhou Shi-Qiang Zhou Dong Wang xiang-Ming Sun Chao-Song Gao Peng-Zhen Zhu Wei-Ping Ren jun {2.u Mu-Xian {2. Chen {2.an Chun-lai Dong PLAC Key Laboratory of Quark and Lepton Physics(MOE)Central China Normal UniversityWuhan 430079China

Topmetal-M2.is a large-area pixel sensor chip fabricated using the GSMC 130 nm CMOS process in *** pixel array of Topmetal-M2.consists of pixels of 400 rows×512.columns with a pixel pitch of 45μm×45μ*** array is divided into 16 subarrays,with pixels of 400 rows×32.columns per *** pixel incorporates two charge sensors:a diode sensor and a Topmetal *** in-pixel circuit primarily consists of a charge-sensitive amplifier for energy measurements,a discriminator with a peak-holding circuit,and a time-to-amplitude converter for time-of-arrival *** pixel of Topmetal-M2.has a charge input range of~0-3 k e-,a voltage output range of~0-180 mV,and a charge-voltage conversion gain of~59.56μV∕e-.The average equivalent noise charge of Topmetal-M2.which includes the readout electronic system noise,is~43.45 e-.In the scanning mode,the time resolution of Topmetal-M2.is 1 LSB=1.2.μs,and the precision is^()7.41μ*** an operating voltage of 1.5 V,Topmetal-M2.has a power consumption of~49 mW∕cm~*** this article,we provide a comprehensive overview of the chip architecture,pixel working principles,and functional behavior of ***,we present the results of preliminary tests conducted on Topmetal-M2.namely,alpha-particle and soft X-ray tests.

关键词： Charge collection Gas detectors Semiconductor detectors X-ray detectors

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The Optical Variability Properties of TeV Blazars

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Research in Astronomy and Astrophysics 2024年第9期24卷 66-75页

作者： Zi-An Su Wen-Xin yang xiang-Tao Zeng Le-Jian Ou Ze-{2.n {2. Jiang-He yang jun-Hui Fan Department of Physics School of Physics and ElectronicsHunan Normal UniversityChangsha 410081China Center for Astrophysics Guangzhou UniversityGuangzhou 510006China Greater Bay Brand Center of the national astronomical Data Center Guangzhou 510006China Astronomy Science and Technology Research Laboratory of Department of Education of Guangdong Province Guangzhou 510006China College of Microelectronics Feicuihu Campus of Hefei University of TechnologyHefei 230601China College of Mathematics and Physics Science Hunan University of Arts and ScienceChangde 415000China

Variability is one of the typical observational properties of blazars and the spectral changes are usually associated with variability,although this kind of association is unclear *** this work,we used data from the Steward {2. blazar monitoring program to investigate the optical variability properties including the short-term timescale,the brightness-dependent spectral property,the correlation between the the brightness variation and the polarization,and then estimate the Doppler factors based on the obtained short timescale to study the polarization property for a sample of 2. TeV *** analyses arrive at the following results:(1)The largest variation amplitude in R-band,ΔR_(M),covers a range from ΔR_(M)=0.2. mag(1ES 2.44+514)to ΔR_(M)=4.66 mag(3C 2.9).(2.Intra-day variability was found from five sources with timescales from 0.14 day for S50716+714 to 0.98 day for PKS *** sources show spectra that are bluer when they become brighter,suggesting a common bluer-when-brighter property.(3)The plot of the polarization versus estimated Doppler factor is consistent with the Doppler factor dependent formula of polarization.(4)The largest polarization is correlated with the largest optical variation,suggesting that the high polarization and high amplitude variation are both the indicator of beaming effect.

关键词： galaxies:active galaxies:jets radiation mechanisms:non-thermal

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Observation of spectral lines in the exceptional GRB 2.1009A

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Science china(Physics,Mechanics & Astronomy) 2024年第8期67卷 187-206页

作者： yan-Qiu Zhang Shao-lin Xiong Ji-Rong Mao Shuang-Nan Zhang Wang-Chen Xue Chao Zheng Jia-Cong liu Zhen Zhang Xi-Lu Wang Ming-Yu Ge Shu-Xu Yi li-Ming Song Zheng-Hua An Ce Cai Xin-Qiao li Wen-Xi Peng Wen-jun Tan Chen-Wei Wang xiang-yang Wen Yue Wang Shuo Xiao Fan Zhang Peng Zhang Shi-Jie Zheng Key Laboratory of Particle Astrophysics Institute of High Energy PhysicsChinese Academy of SciencesBeijing 100049China University of chinese academy of sciences Beijing 100049China yunnan Observatories Chinese Academy of SciencesKunming 650011China Center for astronomical Mega-Science Chinese Academy of SciencesBeijing 100012China Key Laboratory for the Structure and Evolution of Celestial Objects Chinese Academy of SciencesKunming 650216China College of Physics and Hebei Key Laboratory of Photophysics Research and Application Hebei Normal UniversityShijiazhuang 050024China Guizhou Provincial Key Laboratory of Radio Astronomy and Data Processing Guizhou Normal UniversityGuiyang 550001China College of Electronic and Information Engineering Tongji UniversityShanghai 201804China

As the brightest gamma-ray burst ever observed,GRB 2.1009A provided a precious opportunity to explore spectral line *** this article,we performed a comprehensive spectroscopy analysis of GRB 2.1009A jointly with GECAM-C and Fermi/GBM data to search for emission and absorption *** the first time we investigated the line feature throughout this GRB including the most bright part where many instruments suffered problems,and identified prominent emission lines in multiple time *** central energy of the Gaussian emission line evolves from about 37 to 6 MeV,with a nearly constant ratio(about 10%)between the line width and central ***,we find that both the central energy and the energy flux of the emission line evolve with time as a power law decay with power law index of–1 and–2.*** suggest that the observed emission lines most likely origin from the blue-shifted electron positron pair annihilation 511 ke V *** find that a standard high latitude emission scenario cannot fully interpret the observation,thus we propose that the emission line comes from some dense clumps with electron positron pairs traveling together with the *** this scenario,we can use the emission line to directly,for the first time,measure the bulk Lorentz factor of the jet(Γ)and reveal its time evolution(i.e.,Γ~t^(-1))during the prompt ***,we find that the flux of the annihilation line in the co-moving frame keeps *** discoveries of the spectral line features shed new and important lights on the physics of GRB and relativistic jet.

关键词： GRB GRB 2.1009A emission line

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Chemical mixing by turbulent convection in the overshooting region below the convective envelope of RGB stars

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Research in Astronomy and Astrophysics 2011年第11期11卷 1351-1370页

作者： xiang-jun {2. yan li national astronomical Observatories / {2. observatory Chinese Academy of SciencesKunming 650011 China Key Laboratory for the Structure and Evolution of Celestial Objects Chinese Academy ofSciences Kunming 650011 China Graduate University of chinese academy of sciences Beijing 100049 China

Based on the turbulent convection model （TCM）, we investigate chemical mixing in the bottom overshooting region of the convective envelope of intermediatemass stars, focusing on its influence on the formation and extension of blue loops in the Hertzsprung-Russell （HR） diagram. A diffusive mixing model is adopted during the Red Giant Branch （RGB） phase. The properties of the blue loop are changed by modification of the element profiles above the H-burning shell, which results from the incomplete mixing in the bottom overshooting region when the stellar model evolves up along the RGB. Such modification of the element profiles will lead to an increase of opacity in the region just above the H-burning shell and a decrease of opacity in the outer homogeneous convection zone, which will result in a quick decrease of the H-shell nuclear luminosity LH when the stellar model evolves from the RGB tip to its bottom and, finally, a much weaker and smaller convection zone will be obtained in the stellar envelope. This helps to form a longer blue loop. The extension of the blue loop is very sensitive to the parameters （Cx and αTCM） of the diffusive mixing model and of the TCM. The results mainly show that： 1） comparing the results of the classical model with the mixing-length theory, the lengths of the obtained blue loops with different combinations of the values of Cx and αTCM are all increased and the length of the blue loop increases with the values of parameters Cx and αTCM; 2. the diffusive mixing model can significantly extend the time of stellar models lingering on the blue side of the HR diagram, even though the length of the blue loop for the 7M⊙ star has a less prominent difference between the classical and diffusive mixing model; 3） both the observations referring to the location of the Cepheid instability strip and the number ratio NB/NR of blue to red evolved stars in the Galactic open clusters can confine the two parameters in a range of 0.5 ≤ αLTCM ≤ 0.9 and 10-5 ≤

关键词： stars convection-star interiors-star HR diagram-blue loops-Cepheids-Galactic open clusters

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Characteristics of convection and overshooting in RGB and AGB stars

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Research in Astronomy and Astrophysics 2011年第10期11卷 1143-1157页

作者： xiang-jun {2. yan li national astronomical Observatories / {2. observatory Chinese Academy of Sciences Kunming 650011 China Key Laboratory for the Structure and Evolution of Celestial Objects Chinese Academy ofSciences Kunming 650011 China Graduate University of chinese academy of sciences Beijing 100049 China.

Based on the turbulent convection model （TCM） of li ＆ yang, we have studied the characteristics of turbulent convection in the envelopes of {2. 5M⊙ stars at the red giant branch and asymptotic giant branch phases. The TCM has been successfully applied over the entire convective envelopes, including the convective unstable zone and the overshooting regions. We find that the convective motions become progressively stronger when the stellar models are located farther up along the Hayashi line. In the convective unstable zone, we find that the turbulent correlations are proportional to functions of a common factor （V - V^d）T, which explains similar distributions in those correlations. For the TCM we find that if the obtained stellar temperature structure is close to that of the mixing length theory （MLT）, the convective motion will have a much larger velocity and thus be more violent. However, if the turbulent velocity is adjusted to be close to that of the MLT, the superadiabatic convection zone would be much more extended inward, which would lead to a lower effective temperature of the stellar model. For the overshooting distance, we find that the e-folding lengths of the turbulent kinetic energy k in both the top and bottom overshooting regions decrease as the stellar model is progressively located farther up along the Hayashi line, but both the extents of the decrease are not obvious. The overshooting distances of the turbulent correlation /u＇rT＂ are almost the same for the different stellar models with the same set of TCM parameters. For the decay modes of the kinetic energy k, we find that they are very similar for different stellar models based on the same set of TCM parameters, and there is a nearly linear relationship between lg k and In P for different stellar models. When Cs or α increases while the other parameters are fixed, the obtained linearly decaying distance will become longer.

关键词： stars RGB and AGB -- convection of stars -- turbulent convection model convective overshooting

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The In-Flight Realtime Trigger and Localization Software of GECAM

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Research in Astronomy and Astrophysics 2024年第10期24卷 11-24页

作者： Xiao-Yun Zhao Shao-lin Xiong xiang-yang Wen Xin-Qiao li Ce Cai Shuo Xiao Qi Luo Wen-Xi Peng Dong-Ya guo Zheng-Hua An Ke Gong Jin-Yuan liao yan-Qiu Zhang Yue Huang Lu li Xing Wen Fei Zhang Jing Duan Chen-Wei Wang Dong-li Shi Peng Zhang Qi-Bin Yi Chao-yang li yan-Bing Xu Xiao-Hua liang Ya-Qing liu Da-li Zhang Xi-Lei Sun Fan Zhang Gang Chen Huan-Yu Wang Sheng yang Xiao-Jing liu Min Gao Mao-Shun li Jin-Zhou Wang Xing Zhou Yi Zhao Wang-Chen Xue Chao Zheng Jia-Cong liu Xing-Bo Han Jin-ling Qi Jia Huang Ke-Ke Zhang Can Chen Xiong-Tao yang Dong-Jie Hou Yu-Sa Wang Rui Qiao xiang Ma Xiao-Bo li Ping Wang Xin-Ying Song li-Ming Song Shi-Jie Zheng Bing li Hong-Mei Zhang Yue Zhu Wei Chen Jian-Jian He Zhen Zhang Jin Hou Hong-jun Wang yan-Chao Hao xiang-Yu Wang Zong-Yuan yang Zhi-Long Wen Zhi Chang Yuan-Yuan Du Rui Gao Xiao-Fei Lan yan-guo li Gang li Xu-Fang li Fang-jun Lu Hong Lu Bin Meng Feng Shi Hui Wang Hui-Zhen Wang Yu-Peng Xu Jia-Wei yang Xue-Juan yang Shuang-Nan Zhang Chao-Yue Zhang Cheng-Mo Zhang Zhi-Cheng Tang Cheng Cheng Key Laboratory of Particle Astrophysics Institute of High Energy PhysicsChinese Academy of SciencesBeijing 100049China University of chinese academy of sciences Chinese Academy of SciencesBeijing 100049China School of Information Science and Technology Southwest Jiaotong UniversityChengdu 611756China Key Laboratory of Stellar and Interstellar Physics and Department of Physics Xiangtan UniversityXiangtan 411105China Physics and Space Science College China West Normal UniversityNanchong 637002China Department of Astronomy Beijing Normal UniversityBeijing 100875China Innovation academy for Microsatellites of CAS Shanghai 201203China Changchun University of Science and Technology Changchun 130022China chinese academy of sciences South America Center for Astronomy National Astronomical ObservatoriesCASBeijing 100101China

Realtime trigger and localization of bursts are the key functions of GECAM,an all-sky gamma-ray monitor launched on 2.2. December *** developed a multifunctional trigger and localization software operating in the CPU of the GECAM Electronic *** onboard software has the following features:high trigger efficiency for real celestial bursts with a suppression of false triggers caused by charged particle bursts and background fluctuation,dedicated localization algorithm optimized for both short and long bursts,and low time latency of the trigger information which is downlinked through the Global Short Message Communication service of the global BeiDou navigation *** paper provides a detailed description of the design and development of the trigger and localization software system for *** covers the general design,workflow,the main functions,and the algorithms used in the *** paper also includes on-ground trigger tests using simulated gamma-ray bursts generated by a dedicated X-ray tube,as well as an overview of the performance for real celestial bursts during its in-orbit operation.

关键词： telescopes instrumentation:detectors methods:observational

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Cry1Ab rice does not impact biological characters and functional response of Cyrtorhinus lividipennis preying on Nilaparvata lugens eggs

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Journal of Integrative Agriculture 2015年第10期14卷 2011-2018页

作者： CHEN yang lai Feng-{2. SUN yan-qun HONG li-ying TIAN jun-ce ZHANG Zhi-tao FU Qiang State Key Laboratory of Rice Biology China National Rice Research Institute State Key Laboratory of Breeding Base for Zhejiang Sustainable Pest and Disease Control Institute of Plant Protection and Microbiology Zhejiang Academy of Agricultural Sciences

One concern about the use of transgenic plants is their potential risk to natural enemies. In this study, using the eggs of the rice brown planthopper, Nilaparvata lugens, as a food source, we investigated the effects of Cry1 Ab rice on the biological characteristics and functional response of an important predator Cyrtorhinus lividipennis. The results showed that the survival ability（adult emergence rate and egg hatching rate）, development（egg duration, nymphal developmental duration）, adult fresh weight, adult longevity and fecundity of C. lividipennis on Bt rice plants were not significantly different compared to those on non-Bt rice plants. Furthermore, two important parameters of functional response（instantaneous search rate and handling time） were not significantly affected by Bt rice. In conclusion, the tested Cry1 Ab rice does not adversely impact the biological character and functional response of C. lividipennis.

关键词： Bt rice safety assessment non-target organism natural enemy

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Data processing and error analysis for the CE-1 Lunar microwave radiometer

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Research in Astronomy and Astrophysics 2013年第3期13卷 359-372页

作者： Jian-Qing Feng yan Su Jian-jun {2.u Yong-{2.ao Zou Chun-lai {2. national astronomical Observatories Chinese Academy of Sciences

The microwave radiometer （MRM） onboard the Chang＇ E-1 （CE-I） lu- nar orbiter is a 4-frequency microwave radiometer, and it is mainly used to obtain the brightness temperature （TB） of the lunar surface, from which the thickness, temperature, dielectric constant and other related properties of the lunar regolith can be derived. The working mode of the CE-1 MRM, the ground calibration （including the official calibration coefficients）, as well as the acquisition and processing of the raw data are introduced. Our data analysis shows that TB increases with increasing frequency, decreases towards the lunar poles and is significantly affected by solar illumination. Our analysis also reveals that the main uncertainty in TB comes from ground calibration.

关键词： space vehicles -- instruments: microwave radiometer -- Moon: bright-ness temperature -- method: data processing -- error analysis

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