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

Science china(physics,Mechanics & Astronomy) 2024年

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 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 National Astronomical Observatories 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 chinese academy of sciences South African Astronomical Observatory Department of Astronomy University of Cape Town Department of physics University of the Free State Universite' Paris Cite' CNRS Astroparticule et Cosmologie Universite' Paris Cite' CEA Paris-Saclay School of Astronomy and Space sciences 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 University of chinese academy of sciences The University of Tokyo ESA/ESTEC Noordwijk 2201 AZ The Netherlands Department of Astronomy School of physics Huazhong University of Science and Technology INAF-Osservatorio Astrofisico di Torino Sydney institute for Astronomy School of physics Key Laboratory of Particle Astrophysics 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 Hefei School of Astronomy and Space sciences University of Science and Technology of china institute of High Energy physics institute of Deep Space sciences Deep Space Exploration Laboratory Department of Astronomy School of physics and Astronomy Yunnan University Shanghai Astronomical Observatory chinese academy of Science

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 keV,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 keV,with a power-law photon index varying *** X-ray light curve shows a plateau lasting for4d,followed by a steep decay till becoming undetectable10 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 of10 *** detection and follow-ups of more of such objects are essential for revealing their origin.

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核壳结构nAl@Cu(BTC)/Fe(BTC)纳米铝热剂的制备及燃烧性能

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含能材料 2024年第5期32卷 465-474页

作者：史喆赵媛媛马志伟杨玉林张健王旭文梁家燕中国五洲工程设计集团有限公司北京100053 哈尔滨工业大学化工与化学学院新能源转换与存储关键材料技术工业和信息化部重点实验室黑龙江哈尔滨150001

为了解决纳米铝热剂的制备工艺中组分分布不均匀和燃烧效率低等问题,采用层层组装技术将铜‐均苯三甲酸(Cu(BTC))和铁‐均苯三甲酸(Fe(BTC))交替包覆在nAl表面,制备核壳结构nAl@Cu(BTC)/Fe(BTC)纳米铝热剂,并对其结构、形貌、热反应性能... 详细信息

为了解决纳米铝热剂的制备工艺中组分分布不均匀和燃烧效率低等问题,采用层层组装技术将铜‐均苯三甲酸(Cu(BTC))和铁‐均苯三甲酸(Fe(BTC))交替包覆在nAl表面,制备核壳结构nAl@Cu(BTC)/Fe(BTC)纳米铝热剂,并对其结构、形貌、热反应性能(铝热反应温度)和燃烧性能(燃烧时间、点火延迟时间和燃烧温度等)进行研究。结果表明:层层组装技术可以调控包覆层的厚度和形貌,随着包覆层厚度的增加纳米铝热剂从粗糙疏松逐渐变得光滑致密;交替包覆12层Cu(BTC)/Fe(BTC)的纳米铝热剂燃烧剧烈,火焰传播速率较快,在0.710 s内火焰达到最大,具有适中的点火延迟时间(0.509 s)、最短的燃烧时间(2.036 s)和最高的燃烧温度(1425℃),此时,Cu(BTC)和Fe(BTC)的协同作用使其铝氧化反应温度峰值降低到552.5℃和735.0℃。

关键词：核壳结构纳米铝热剂 nAl@Cu(BTC)/Fe(BTC) 层层组装技术燃烧性能

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某废弃冶炼场地土壤不同粒径组分重金属的特征及其对修复策略的启示

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Journal of Central South University 2024年第4期31卷 1076-1091页

作者：赵鹏 Muhammad ADNAN 肖佩文杨雪枫王海燕肖保华薛生国 State Key Laboratory of Environmental Geochemistry Institute of GeochemistryChinese Academy of SciencesGuiyang 550081China University of chinese academy of sciences Beijing 100049China School of Metallurgy and Environment Central South UniversityChangsha 410083China

颗粒粒径组分对土壤重金属的分布与赋存具有重要影响,而当前对受冶炼活动影响的不同区域间土壤各粒径组分重金属分布的比较研究较少。本研究以某废弃铅冶炼场地为研究对象,选取三个土壤剖面(冶炼固废堆存区、交通区和邻近的农田),对比... 详细信息

颗粒粒径组分对土壤重金属的分布与赋存具有重要影响,而当前对受冶炼活动影响的不同区域间土壤各粒径组分重金属分布的比较研究较少。本研究以某废弃铅冶炼场地为研究对象,选取三个土壤剖面(冶炼固废堆存区、交通区和邻近的农田),对比研究了不同土壤颗粒粒径组分(>150、45~150和45μm)具有较高的重金属质量负载量(>50%),且废渣颗粒对土壤重金属的贡献显著,故物理分离技术可用于该场地的土壤污染修复。此外,石膏和莫来石可能是该场地受冶炼活动影响土壤的指示矿物。本研究将冶炼活动影响与土壤不同粒径组分重金属的赋存形态相关联,对修复策略具有一定的指导意义。

关键词：废弃铅冶炼场地土壤重金属颗粒粒径组分地球化学形态废渣物理分离技术

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Genome size of 14 species of fireflies (Insecta, Coleoptera, Lampyridae)

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Zoological Research 2017年第6期38卷 449-458页

作者： Gui-Chun Liu Zhi-Wei Dong Jin-Wu He Ruo-ping zhao wen wang Xue-Yan Li State Key Laboratory of Genetic Resources and Evolution Kunming Institute of Zoology Chinese Academy of Sciences Kunming Yunnan 650223 China University of chinese academy of sciences Beijing 100049 China Center for Ecological and Environmental sciences Key Laboratory for Space Bioscience & Biotechnology Northwestern Polytechnical University Xi'an Shaanxi 710072 China

Eukaryotic genome size data are important both as the basis for comparative research into genome evolution and as estimators of the cost and difficulty of genome sequencing programs for non-model organisms. In this study, the genome size of 14 species of fireflies （Lampyridae）（two genera in Lampyrinae, three genera in Luciolinae, and one genus in subfamily incertae sedis） were estimated by propidium iodide （PI）-based flow cytometry. The haploid genome sizes of Lampyridae ranged from 0.42 to 1.31 pg, a 3.1-fold span. Genome sizes of the fireflies varied within the tested subfamilies and genera. Lamprigera and Pyrocoelia species had large and small genome sizes, respectively. No correlation was found between genome size and morphological traits such as body length, body width, eye width, and antennal length. Our data provide additional information on genome size estimation of the firefly family Lampyridae. Furthermore, this study will help clarify the cost and difficulty of genome sequencing programs for non-model organisms and will help promote studies on firefly genome evolution.

关键词： Haploid genome size Firefly Flow cytometry Evolution

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Toward an ideal electrical resistance strain gauge using a bare and single straight strand metallic glassy fiber

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Science china(physics,Mechanics & Astronomy) 2012年第4期55卷 609-613页

作者： YI Jun HUO LiShan zhao DeQian PAN MinXiang BAI HaiYang wang weihua institute of physics Chinese Academy of SciencesBeijing 100190China

Electrical resistance strain gauges(SGs) are useful tools for experimental stress analysis and the strain sensing elements in many electromechanical transducers including load cells,pressure transducers,torque meters,accelerometers,force cells,displacement transducers and so *** commonly used commercial crystalline strain sensing materials of SGs are in the form of wire or foil of which performance and reliability is not good enough due to their low electrical resistivity and incapacity to get thin *** SGs with single straight strand strain sensing materials,which are called ideal SG,are highly desirable for more than seven decades since the first SG was ***,we show the development of a type of minuscule length scale strain gauge by using a bare and single straight strand metallic glassy fiber(MGF) with high resistivity,much smaller lengthscale,high elastic limits(2.16%) and especially the super piezoresistance *** anticipate that our metallic glassy fiber strain gauge(MGFSG),which moves toward the ideal SGs,would have wide applications for electromechanical transducers and stress analysis and catalyze development of more micro-and nanoscale metallic glass applications.

关键词： metallic glassy fiber strain gauge strain sensing material metallic glassy fiber strain gauge

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兼顾调节特性和经济成本的调压室体型优化策略

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中国农村水利水电 2024年第6期 259-265页

作者：王航陈帝伊雷刘伟刘泳赵子文周叶西北农林科技大学水利与建筑工程学院陕西杨凌712100 中国水利水电科学研究院北京100038

过渡过程动态特性和调压室建设成本是调压室体型设计中需要关注的两个主要方面。如何选取调压室体型参数使两者均达到最优对水电站建设和运行具有重要意义。针对这一问题,基于第三代非支配排序遗传算法(NSGA-Ⅲ)和优劣解距离评价方法(TO... 详细信息

过渡过程动态特性和调压室建设成本是调压室体型设计中需要关注的两个主要方面。如何选取调压室体型参数使两者均达到最优对水电站建设和运行具有重要意义。针对这一问题,基于第三代非支配排序遗传算法(NSGA-Ⅲ)和优劣解距离评价方法(TOPSIS),提出了一种兼顾大小波动调节特性和工程投资最优的调压室体型优化策略。首先,基于特征线法,建立水力发电系统精细化模型。其次,以调压室断面直径、阻抗孔直径和安装位置为决策变量,分别建立以大波动动态特性(机组最大水头+机组转速最大上升率)与调压室体积为目标的大波动优化模型和以转速超调量与ITAE为目标的小波动优化模型,并引入NSGA-Ⅲ算法,得到调压室在两种优化模型下的Pareto解集。最后,基于TOPSIS评价方法,以上述4个优化目标为决策层,对Pareto解集进一步评价,得到兼顾大小波动调节特性和经济性最优的调压室体型。结果表明,与得分最低的方案相比,最优方案在牺牲较小调压室经济性的前提下,能够有效改善大小波动综合调节特性,实现平衡调压室建设成本和大小波动综合调节特性的目标。研究结果对水电站调压室结构设计具有重要指导意义。

关键词：水力发电系统调节特性调压室体型优化 NSGA-Ⅲ TOPSIS

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Acid-induced rearrangement-hydration of koumine——hydrakouminol and neo-dihydrokoumine

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chinese Journal of Chemistry 1986年第3期4卷 225-229页

作者： LIU Chu-Tsin wang Qi-wen FAN zhao-Chang wang Chi-Hao PEI Ya-Qiong Shanghai institute of Organic Chemistry, Academia Sinica, Shanghai institute of Environmental Chemistry, Academia Sinica, beijing Shanghai institute of Organic Chemistry Academia Sinica Shanghai institute of Environmental Chemistry Academia Sinica Beijing

From a long-stored hydrochloric acid extract of the chinese toxic plant Kou-wen （Gelse-mium elegans Benth）, hydrakouminol, C20H24N2O2（M+324.1814） has been isolated. It has beenassigned a structure 2 according to spectroscopic analysis, and considered to be resulting from anextremely slow process of proton-induced hydration of koumine, 1, via two consecutive Wagner-Meerwein rearrangements, as shown in Scheme 1. The proposed structure 2 has been sup-ported by its reduction with borane complex in hydrochloric acid into neo-dihydrokoumine 3, thestructure of which has been determined by1H and13C NMR analyses and confirmed by X-ray crystal-lography. The probable mechanism for the formation of 2 and 3 has been discussed.

关键词： hydrakouminol and neo-dihydrokoumine Acid-induced rearrangement-hydration of koumine

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一种新的高效MMSE-SIC检测算法

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系统仿真学报 2011年第7期23卷 1350-1353页

作者：包亚伟赵慧蒋华王文博吴斌泛网无线通信教育部重点实验室北京邮电大学北京100876 北京电子科技学院北京100070 中国科学院微电子研究所北京100029

传统的V-BLAST系统检测算法,由于存在矩阵求逆的操作,其计算复杂度与发射天线数的立方成正比,在发射天线较多时,对接收机信号处理能力要求较高。于是提出了一种具有更低复杂度的排序串行干扰消除算法。该算法利用施密特正交化分解方法,... 详细信息

传统的V-BLAST系统检测算法,由于存在矩阵求逆的操作,其计算复杂度与发射天线数的立方成正比,在发射天线较多时,对接收机信号处理能力要求较高。于是提出了一种具有更低复杂度的排序串行干扰消除算法。该算法利用施密特正交化分解方法,有效地避免了循环矩阵求逆运算,在不降低误比特率性能的情况下,使得检测算法大为简化,其计算复杂度与发射天线数的平方成正比。同时,该算法使排序和检测过程相互独立出来,提高了算法应用的灵活性。

关键词：垂直-贝尔实验室分层空时结构最小均方误差检测排序施密特正交化

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Fabrication of Zn-Ti layered double hydroxide by varying cationic ratio of Ti^(4+) and its application as UV absorbent

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chinese Chemical Letters 2017年第2期28卷 394-399页

作者： Xin-Rui wang Yong Li Li-ping Tang wen Gan Wei Zhou Yu-Fei zhao Dong-Sheng Bai beijing Key Lab of Plant Resource Research and Development/Department of Chemistry School of Science Beijing Technology and Business University Key Laboratory of Photochemical Conversion and Optoelectronic Materials Technical Institute of Physics and Chemistry Chinese Academy of Sciences

ZnTi-layered double hydroxides（LDHs） with varying Zn/Ti ratio have been synthesized by coprecipitation of zinc and titanium salts from homogeneous *** obtained ZnTi-LDHs possess high crystallinity and hierarchical structure with improved UV-absorbance *** UV-vis spectra show that the UV absorbing properties of ZnTi-LDHs is stronger and broader than both MgAl-LDH and ZnAl-LDH due to the existence of ***,the UV absorption property increased with the content of Ti,which can be ascribed to the decrease in the band gap energy,as clearly confirmed by density functional theory *** irradiated by UV rays,the property of the samples with generated free radicals（OH^·and O2^·） was evaluated by means of electron spin resonance（EPR）.ZnTi-LDHs generated a relatively lower active radicals in contrast with TiO2 and ZnO,which implied an increased safety used as ***,this work provides a detailed understanding of UV shielding properties of ZnTiLDHs which was unrevealed previously,and demonstrates the expansive application prospects of ZnTiLDHs in the field of sunscreens.

关键词： Layered double hydroxide UV absorbent Density functional theory calculations Photoactivity Band gap

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Optimization of denitrifying phosphorus removal in a predenitrification anaerobic/anoxic/post-aeration+nitrification sequence batch reactor(pre-A_(2)NSBR)system:Nitrate recycling,carbon/nitrogen ratio and carbon source type

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Frontiers of Environmental Science & Engineering 2018年第5期12卷 91-100页

作者： weihua zhao Meixiang wang Jianwei Li Yu Huang Baikun Li Cong Pan Xiyao Li Yongzhen Peng National Engineering Laboratory for Advanced Municipal Wastewater Treatment and Reuse Technology Engineering Research Center of BeijingBeijing University of TechnologyBeijing 100124China School of Marine Science and Technology Sino-Europe Membrane Technology Research InstituteHarbin Institute of TechnologyWeihai 264209China

Because the efficiency of biological nutrient removal is always limited by the deficient carbon source for the low carbon/nitrogen(C/N)ratio in real domestic sewage,the denitrifying phosphorus removal(DNPR)was developed as a simple and efficient method to remove nitrogen and *** addition,this method has the advantage of saving aeration energy while reducing the sludge *** this context,a pre-denitrification anaerobic/anoxic/post-aeration+nitrification sequence batch reactor(pre-A_(2)NSBR)system,which could also reduce high ammonia effluent concentration in the traditional two-sludge DNPR process,is proposed in this *** pre-A_(2)NSBR process was mainly composed of a DNPR SBR and a nitrifying SBR,operating as alternating anaerobic/anoxic/post-aeration+nitrification ***,the long-term performance of different nitrate recycling ratios(0-300%)and C/N ratios(2.5-8.8),carbon source type,and functional microbial community were *** results showed that the removal efficiency of total inorganic nitrogen(TIN,including NH4^(+)-N,NO_(2)^(-)-N,and NO_(3)^(-)-N)gradually increased with the nitrate recycling ratios,and the system reached the highest DNPR efficiency of 94.45% at the nitrate recycling ratio of 300%.The optimum C/N ratio was around 3.9-7.3 with a nitrogen and phosphorus removal efficiency of 80.15%and 93.57%,*** acetate was proved to be a high-quality carbon source for DNPR *** results of fluorescence in situ hybridization(FISH)analysis indicated that nitrifiers and phosphorus accumulating organisms(PAOs)were accumulated with a proportion of 19.41%and 26.48%,respectively.

关键词： Denitrifying phosphorus removal C/N ratio Nitrate recycling Carbon source type Biological nutrient removal Pre-A_(2)NSBR system

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