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Einstein Probe discovery of EP240408a: A peculiar X-ray transient with an intermediate timescale

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Science China(physics,Mechanics & Astronomy) 2025年第1期Mechanics & Astronomy) .卷 222-240页

作者： Wenda Zhang Weimin Yuan Zhixing Ling Yong Chen Nanda Rea Arne Rau Zhiming Cai Huaqing Cheng Francesco Coti Zelati Lixin Dai Jingwei Hu Shumei Jia Chichuan Jin Dongyue Li Paul O’Brien Rongfeng Shen Xinwen Shu Shengli Sun Xiaojin Sun Xiaofeng Wang Lei Yang Bing Zhang Chen Zhang Shuang-Nan Zhang Yonghe Zhang Jie An David Buckley Alexis Coleiro Bertrand Cordier Liming Dou Rob Eyles-Ferris Zhou Fan Hua Feng Shaoyu Fu Johan P.U.Fynbo Lluis Galbany Saurabh W.Jha Shuaiqing Jiang Albert Kong Erik Kuulkers Weihua Lei Wenxiong Li Bifang Liu Mingjun Liu Xing Liu Yuan Liu Zhu Liu Chandreyee Maitra Alessio Marino Itumeleng Monageng Kirpal Nandra Jeremy Sanders Roberto Soria Lian Tao Junfeng Wang Song Wang Tinggui Wang Zhongxiang Wang Qingwen Wu Xuefeng Wu Dong Xu Yanjun Xu Suijian Xue Yongquan Xue Zijian Zhang Zipei Zhu Hu Zou Congying Bao Fansheng Chen Houlei Chen Tianxiang Chen Wei Chen Yehai Chen Yifan Chen Chenzhou Cui Weiwei Cui Yanfeng Dai Dongwei Fan Ju Guan Dawei Han Dongjie Hou Haibo Hu Maohai Huang Jia Huo Zhenqing Jia Bowen Jiang Ge Jin Chengkui Li Junfei Li Longhui Li Maoshun Li Wei Li Zhengda Li Tianying Lian Congzhan Liu Heyang Liu Huaqiu Liu Fangjun Lu Laidan Luo Jia Ma Xuan Mao Haiwu Pan Xin Pan Liming Song Hui Sun Yunyin Tan Qingjun Tang Yihan Tao Hao Wang Juan Wang Lei Wang Wenxin Wang Yilong Wang Yusa Wang Qinyu Wu Haitao Xu Jingjing Xu Xinpeng Xu Yunfei Xu Zhao Xu Changbin Xue Yulong Xue Ailiang Yan Haonan Yang Xiongtao Yang Yanji Yang Juan Zhang Mo Zhang Wenjie Zhang Zhen Zhang Zhen Zhang Ziliang Zhang Donghua Zhao Haisheng Zhao Xiaofan Zhao Zijian Zhao Hongyan Zhou Yilin Zhou Yuxuan Zhu Zhencai Zhu National Astronomical Observatories Chinese Academy of Sciences School of Astronomy and Space Sciences University of Chinese Academy of Sciences Key Laboratory of Particle Astrophysics institute of High Energy physics Chinese Academy of Sciences institute of Space Sciences (ICE) CSIC Institut d’Estudis Espacials de Catalunya (IEEC) Max Planck institute for Extraterrestrial physics Innovation Academy for Microsatellites Chinese Academy of Sciences Department of physics University of Hong Kong School of physics and Astronomy University of Leicester School of physics and Astronomy Sun Yat-sen University Department of physics Anhui Normal University Shanghai institute of technical physics Chinese Academy of Sciences physics Department Tsinghua University Nevada Center for Astrophysics University of Nevada Las Vegas Department of physics and Astronomy University of Nevada Las Vegas South African Astronomical Observatory Department of Astronomy University of Cape Town Department of physics University of the Free State Université Paris Cité CNRS Astroparticule et Cosmologie Université Paris Cité CEA Paris-Saclay IRFU/DAp-AIM Department of Astronomy Guangzhou University Cosmic Dawn Center (DAWN) Niels Bohr institute University of Copenhagen Department of physics and Astronomy Rutgers the State University of New Jersey institute for Cosmic Ray Research The University of Tokyo ESA/ESTEC Department of Astronomy School of physics Huazhong University of Science and Technology INAF-Osservatorio Astrofisico di Torino Sydney institute for Astronomy School of physics The University of Sydney Department of Astronomy Xiamen University institute for Frontiers in Astronomy and Astrophysics Beijing Normal University Department of Astronomy University of Science and Technology School of Astronomy and Space Sciences University of Science and Technology of China institute of Deep Space Sciences Deep Space Exploration Laboratory Department of Astronomy School of physics and Astronomy Yunnan University Shanghai Astronomical Observatory Chi

We report the discovery of a peculiar X-ray transient,EP240408a,by Einstein Probe （EP） and follow-up studies made with EP,Swift,NICER,GROND,ATCA and other ground-based multiwavelength *** new transient was first detected with Wide-field X-ray Telescope （WXT） on board EP on April 8th,2024,manifested in an intense yet brief X-ray flare lasting for *** flare reached a peak flux of 3.9×10-9erg cm-2s-1in 0.5-4 ke V,～300 times brighter than the underlying X-ray emission detected throughout the *** and more precise follow-up observations by EP/FXT,Swift and NICER confirmed the finding of this new *** X-ray spectrum is non-thermal in 0.5-10 ke V,with a power-law photon index varying *** X-ray light curve shows a plateau lasting for ～4 d,followed by a steep decay till becoming undetectable ～10 d after the initial *** on its temporal property and constraints from previous EP observations,an unusual timescale in the range of 7-23 d is found for EP240408a,which is intermediate between the commonly found fast and long-term *** counterparts have been found in optical and near-infrared,with the earliest observation at 17 h after the initial X-ray detection,suggestive of intrinsically weak emission in these *** demonstrate that the remarkable properties of EP240408a are inconsistent with any of the transient types known so far,by comparison with,in particular,jetted tidal disruption events,gamma-ray bursts,X-ray binaries and fast blue optical *** nature of EP240408a thus remains an *** suggest that EP240408a may represent a new type of transients with intermediate timescales of the order of～10 *** detection and follow-ups of more of such objects are essential for revealing their origin.

关键词： X-ray transients ${\bm~{Einstein~~Probe}}$

Satellite remote sensing reveals overwhelming recovery of forest from disturbances in Asia

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Atmospheric and Oceanic Science Letters 2025年第1期18卷 46-51页

作者： Yiying Zhu Hesong Wang Anzhi Zhang School of Ecology and Nature Conservation Beijing Forestry UniversityBeijingChina Key Laboratory of Regional Climate and Environment for Temperate East Asia Institute of Atmospheric PhysicsChinese Academy of SciencesBeijingChina College of Forestry and Landscape Architecture Xinjiang Agricultural UniversityUrumqiChina

Forest ecosystems play key roles in mitigating human-induced climate change through enhanced carbon uptake;however,frequently occurring climate extremes and human activities have considerably threatened the stability of *** the same time,detailed accounts of disturbances and forest responses are not yet well quantified in *** study employed the Breaks For Additive Seasonal and Trend method-an abrupt-change detection method-to analyze the Enhanced Vegetation Index time series in East Asia,South Asia,and Southeast *** approach allowed us to detect forest disturbance and quantify the resilience after *** showed that 20%of forests experienced disturbance with an increasing trend from 2000 to 2022,and Southeast Asian countries were more severely affected by ***,95%of forests had robust resilience and could recover from disturbance within a few *** resilience of forests suffering from greater magnitude of disturbance tended to be stronger than forests with lower disturbance *** summary,this study investigated the resilience of forests across the low and middle latitudes of Asia over the past two *** authors found that most forests exhibited good resilience after disturbance and about two-thirds had recovered to a better state in *** findings of this study underscore the complex relationship between disturbance and resilience,contributing to comprehension of forest resilience through satellite remote sensing.

关键词： Forest ecosystem Enhanced vegetation index Breaks for additive seasonal and trend method Disturbance Resilience

Total Ionizing Dose Effect and Failure Mechanism of Digital Signal Processor

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Chinese Journal of Electronics 2021年第5期30卷 986-990页

作者： YU Xin LU Wu LI Xiaolong LIU Mohan WANG Xin SUN Jing GUO Qi xinjiang technical institute of physics and chemistry Laboratory of Solid State Radiation Physics

Ionizing radiation effect and failure mechanism of Digital signal processor(DSP) is studied through test-board and automatic test equipment to find the relationship between system function failure and parameter degradation. Static bias is more sensitive than dynamic bias when DSP is tested on-line during radiation. Core current, high-Z leakage current and timing parameter are sensitive to ionizing radiation. No enhanced low-dose-rate sensitivity is found by comparing experiment results under high and low dose rate *** memory interface and Timer are deduced to be the sensitive module by step radiation and analysis basing full parameter test in Verigy 93000. The timing parameter degradation have a strong correlation to these module functions. And the degeneration mechanism is analysed on inverter through Hspice simulation which indicate the leakage circuit caused by radiation can lead a delay to the digital signal propagating. The parasitical capacitance among long connections make it worse to the data transmission around DSP, field programmable gate array and memory. Then an early function failure occurs in test board than Verigy 93000. This work provide support to systematic radiation hardness design and hardness assurance/lot acceptance testing in space applications.

关键词： Verigy 93000 analysis basing full parameter test digital signal propagating radiation effect radiation effects DSP external memory interface leakage currents early function failure leakage circuit test board sensitive module system function failure high dose rate radiation static bias automatic test equipment timing parameter degradation low dose rate radiation field programmable gate array enhanced low-dose-rate sensitivity Digital signal processor degeneration mechanism systematic radiation hardness design radiation hardening (electronics) field programmable gate arrays integrated circuit testing ionizing radiation dynamic bias module functions step radiation digital signal processing chips failure mechanism test-board

Synthesis and characterization of LiCo_(1/3)Ni_(1/3)Mn_(1/3)O_2 prepared by Pechini process

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Rare Metals 2006年第Z1期25卷 7-11页

作者： LI Zhigang WANG Tiandiao KANG Xueya xinjiang technical institute of physics and chemistry Chinese Academy of Sciences Urumuqi 830011 China Graduate University of Chinese Academy of Sciences Beijing 100049 China Xinjiang Technical Institute of Physics and Chemistry Chinese Academy of Sciences Urumuqi 830011 China Xinjiang Technical Institute of Physics and Chemistry Chinese Academy of Sciences Urumuqi 830011 China

Layered cathode material LiCo1/3Ni1/3Mn1/3O2 was synthesized by Pechini process, and investigated using X-ray diffraction (XRD), scanning electron microscopy (SEM) and galvanostatic charge/discharge cycling. The sample is well-crystallized and has a phase-pure a-NaFeO2 structure. The particle sizes are uniform, and distributed in the range of 20-200 nm. The initial discharge capacity of the Li/LiCo1/3Ni1/3Mn1/3O2 cell was about 149 mAh·g-1 when it was cycled at a voltage range of 4.5-2.3 V with a specific current of 0.25 mA. The result is better in comparison with solid-state solution method. The synthetic procedure was discussed. Three major reactions: chelation, esterification, and polymerization successively occurred.

关键词： layered cathode material LiCo_(1/3)Ni_(1/3)Mn_(1/3)O_2 Pechini method structure morphology electrochemical properties

Enhancing the photoluminescence intensity of CaTiO_3:Eu^(3+) red phosphors with magnesium

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Journal of Rare Earths 2015年第10期33卷 1036-1039页

作者：张杰强范艳伟陈朝阳王军华赵鹏君郝斌 Key Laboratory of Functional Materials and Devices for Special Environments of CAS Xinjiang Technical Institute of Physics & Chemistry of CAS xinjiang Key Laboratory of Electronic Information Materials and Devices Xinjiang Technical Institute of Physics & Chemistry of CAS University of Chinese Academy of Sciences

Red phosphors MgxCa1-xTiO3：Eu3＋（0〈x〈0.5） were synthesized by solid-state reaction method. The crystalline structure and morphology of the as-prepared samples were confirmed by X-ray diffraction （XRD） and scanning electron microscopy （SEM）. The luminescence property was measured using photoluminescence excitation and photoluminescence emission spectra. Results showed that spherical particles appeared in the phosphor bodies and size of the phosphor particles were tmiformly distributed in the range of 600-800 nm when the Mg2＋ concentration was about 40 mol.%. It could readily be seen that the strongest PL emission was located at 617 nm monitored at 398 nm, which well matched with the near ultraviolet （NUV, 395400 nm） GaN-LEDs. More importantly, PL emission intensity （617 nm） of phosphor ***0.6TiO3：0.03Eu3＋ was 4.26 times of that of phosphor CaTiO3：0.03Eu3＋ Based on these results, it implied that the PL intensity of phosphorCaTiO3：0.03Eu3＋ could be significantly enhanced by introducing Mg2＋ into CaTiO3 host lattices and the phosphor Mg0.4Ca0.6TiO3：0.03Eu3＋ might be the promising red-emitting phosphor in making tricolor phosphor converted white-LEDs.

关键词： red phosphor MgxCa1-xTiO3:Eu3+Mg 2+ concentration photoluminescence rare earths

The study on optically stimulated luminescence dosimeter based on the SrS:Eu,Sm and CaS:Eu,Sm

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Chinese physics B 2008年第8期17卷 3156-3162页

作者：刘艳平陈朝阳范艳伟巴维真郭旗陆妩汤新强杜彦召 xinjiang technical institute of physics & chemistry Chinese Academy of Sciences Graduate School of Chinese Academy of Sciences

With the increasing use of nuclear energy, there is a need for a wider range of efficient dosimeters for radiation detection and assessment. There has been a tremendous growth in the development of radiation detectors and devices in the past few decades. In recent years, the development of new materials for radiation dosimetry has progressed significantly. Alkaline earth sulfides （AES） have been known for a long time as excellent and versatile phosphor materials. In the present investigation, a number of phosphor samples such as mono-, binary and ternary sulfides of alkaline earths （II^a-VI^b） have been prepared and their TL properties have been studied with respect to exposure （x-ray） response and fading. In this paper, some results on SrS：Eu, Sm and CaS：Eu, Sm phosphors are presented. A type of novel OSL dosimeter is described. The dosimeter takes advantage of the characteristics of charge trapping materials SrS：Eu, Sm and CaS：Eu, Sm that exhibit optically stimulated luminescence （OSL）. The measuring range of the dosimeter is from 0.01 to 1000 Gy. The OSL dosimeters provide capability for remote monitoring radiation locations which are difficult to access and hazardous. This equipment is relatively simple, small in size and has low power consumption. The device is suitable for space radiation dose exploration. In addition, it also can be used in IC and other radiation occasions and has good prospects.

关键词： optically stimulated luminescence radiation dosimeter

A study on the real-time radiation dosimetry measurement system based on optically stimulated luminescence

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Chinese physics C 2008年第5期32卷 381-384页

作者：刘艳平陈朝阳巴维真范艳伟杜彦召潘世列郭旗 xinjiang technical institute of physics & chemistry Chinese Academy of SciencesUrumchi 830011China Graduate University of Chinese Academy of SciencesBeijing 100049China xinjiang technical institute of physics & chemistry Chinese Academy of SciencesUrumchi 830011China

The optically stimulated luminescent （OSL） radiation dosimeter technically surveys a wide dynamic t range and a high sensitivity. Optical fiber dosimeters provide capability for remote monitoring of the radiation in the locations which are difficult-to-access and hazardous. In addition, optical fiber dosimeters are immune to electrical and radio-frequency interference. In this paper, a novel remote optical fiber radiation dosimeter is described. The optical fiber dosimeter takes advantage of the charge trapping materials CaS：Ce, Sm that exhibit OSL. The measuring range of the dosimeter is from 0.1 to 100 Gy. The equipment is relatively simple and small in size, and has low power consumption. This device is suitable for measuring the space radiation dose and also can be used in high radiation dose condition and other dangerous radiation occasions.

关键词： optically stimulated 1 online and realtime dosimeter

NTC and electrical properties of nickel and gold doped n-type silicon material

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Journal of Semiconductors 2009年第8期30卷 52-55页

作者：董茂进陈朝阳范艳伟王军华陶明德丛秀云 xinjiang technical institute of physics & chemistry Chinese Academy of Sciences Graduate University of the Chinese Academy of Sciences

Silicon materials compensated by deep level impurities such as nickel and gold have negative temperature coefficient （NTC） characteristics. In this work, n-type silicon wafers are smeared by nickel chloride ethanol solution and gold chloric acid ethanol solution, and subsequently put in the opening environment to heat. The electrical resistance and B-value of the thermistors made by this silicon material are measured and analyzed. When the silicon surface concentration of gold atoms is 2 × 10-6 mol/cm2, the uniformity of the single-crystal silicon material is optimal. When the diffusion temperature is between 900 and 1000 ℃, a material with high B-value and low electrical resistivity is obtained. The B-T and R-T change laws calculated by the theory of semiconductor deep level energy are basically consistent with the experimental results.

关键词： deep level impurities nickel gold NTC electrical properties

Annealing behavior of radiation damage in JFET-input operational amplifiers

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Journal of Semiconductors 2009年第5期30卷 60-64页

作者：郑玉展陆妩任迪远王义元郭旗余学锋 xinjiang technical institute of physics and chemistry Chinese Academy of Sciences Graduate University of Chinese Academy of Sciences

The elevated and room temperature annealing behavior of radiation damage in JFET-input operational amplifiers （op-amps） were investigated. High- and low-dose-rate irradiation results show that one of the JFET-input op-amps studied in this paper exhibits enhanced low-dose-rate sensitivity and the other shows time-dependent effect. The offset voltage of both op-amps increases during long-term annealing at room temperature. However, the offset voltage decreases at elevated temperature. The dramatic difference in annealing behavior at room and elevated temperatures indicates the migration behavior of radiation-induced species at elevated and room temperatures. This provides useful information to understand the degradation and annealing mechanisms in JFET-input op-amps under total ionizing radiation. Moreover, the annealing of oxide trapped charges should be taken into consideration, when using elevated temperature methods to evaluate low-dose-rate damage.

关键词： JFET-input operational amplifiers dose rate radiation damage annealing behavior