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Optimization of performance of the KM2A full array using the Crab Nebula

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Chinese Physics C 2024年第6期48卷 169-178页

作者：曹臻 F.Aharonian 安琪阿西克古白云翔包逸炜 D.bastieri 毕效军毕玉江蔡金庭曹晴曹文羽曹喆常进常劲帆陈尚明陈恩生陈亮陈林陈龙陈明君陈玛丽陈起辉陈素弘陈天禄陈阳程宁程耀东崔明阳崔树旺崔晓红崔昱东戴本忠代洪亮戴子高单增罗布 D.della Volpe 董绪强段凯凯樊军辉范一中方军方堃冯存峰封莉冯少辉丰晓婷冯有亮 S.Gabici 高博高川东高林青高启高卫高伟康葛茂茂耿利斯 G.Giacinti 龚光华苟全补顾旻皓郭福来郭晓磊郭义庆郭莹莹韩毅昂何会海贺昊宁何佳银何新波何钰 M.Heller 贺远强侯博文侯超侯贤胡红波胡铨胡世聪黄代绘黄天奇黄文俊黄性涛黄晓渊黄勇黄志成季筱璐贾焕玉贾康江琨姜晓巍姜泽军金敏康明铭柯通 D.Kuleshov.K.Kurinov 李兵兵李澄李骢李丹李飞李海波李会财李华阳李军李剑李捷李凯李文龙李文莲李秀荣李昕李一卓李哲黎卓梁恩维梁云峰林苏杰刘冰刘成刘栋刘虎刘海东刘佳刘江来刘金艳刘茂元柳若愚刘四明刘伟刘怡刘以农鲁睿罗晴吕洪魁马伯强马玲玲马欣华毛基荣闵振 W.Mitthumsiri 穆慧君南云程 A.Neronov 区子维庞彬宇 P.Pattarakijwanich 裴致远齐孟尧祁业情乔冰强秦家军 D.Ruffolo A.Sáiz D.Semikoz 邵澄宇邵琅 O.Shchegolev 盛祥东舒富文宋慧超 Yu.V.Stenkin V.Stepanov 苏扬孙秦宁孙晓娜孙志斌谭柏轩唐庆文唐泽波田文武王超王昌贝王广威王洪光王惠惠王建成汪凯王利苹王玲玉王培汉王冉王为王祥高王祥玉王阳王玉东王岩谨王忠海王仲翔王振王铮韦大明魏俊杰魏永健文韬吴超勇吴含荣武莎吴雪峰吴雨生席邵强夏捷夏君集项光漫肖迪泫肖刚辛广广辛玉良邢祎熊峥徐东莲徐仁峰徐仁新徐伟立薛良闫大海颜景志颜田杨朝文杨帆杨冯帆杨何文杨佳盈杨莉莉杨明洁杨睿智杨深邦姚玉华姚志国叶一锰尹丽巧尹娜游晓浩游智勇于艳红袁强岳华曾厚敦曾婷轩曾玮查敏张彬彬张丰张海明张恒英张建立张丽霞张力张鹏飞张佩佩张瑞张少博张少如张寿山张潇张笑鹏张云峰张毅张勇赵兵赵静赵雷赵立志赵世平郑福周斌周浩周佳能周猛周平周荣周勋秀祝成光祝凤荣朱辉朱科军左雄 LHAASO Collaboration Key Laboratory of Particle Astrophyics&Experimental Physics Division&Computing Center Institute of High Energy PhysicsChinese Academy of SciencesBeijing 100049China University of Chinese Academy of Sciences Beijing 100049China Tianfu Cosmic Ray Research Center Chengdu 610000China Dublin Institute for Advanced Studies 31 Fitzwilliam Place2 DublinIreland Max-Planck-Institut for Nuclear Physics P.O.Box 10398069029 HeidelbergGermany State Key Laboratory of Particle Detection and Electronics China University of Science and Technology of China Hefei 230026China School of Physical Science and Technology&School of Information Science and Technology Southwest Jiaotong UniversityChengdu 610031China School of Astronomy and Space Science Nanjing UniversityNanjing 210023China Center for Astrophysics Guangzhou UniversityGuangzhou 510006China Hebei Normal University Shijiazhuang 050024China Key Laboratory of Dark Matter and Space Astronomy&Key Laboratory of Radio Astronomy Purple Mountain ObservatoryChinese Academy of SciencesNanjing 210023China Tsung-Dao Lee Institute&School of Physics and Astronomy Shanghai Jiao Tong UniversityShanghai 200240China Key Laboratory for Research in Galaxies and Cosmology Shanghai Astronomical ObservatoryChinese Academy of SciencesShanghai 200030China Key Laboratory of Cosmic Rays(Tibet University) Ministry of EducationLhasa 850000TibetChina National Astronomical Observatories Chinese Academy of SciencesBeijing 100101China School of Physics and Astronomy(zhuhai)&School of Physics(Guangzhou)&Sino-French Institute of Nuclear Engineering and Technology(zhuhai) Sun Yat-sen UniversityZhuhai 519000&Guangzhou 510275China School of Physics and Astronomy Yunnan UniversityKunming 650091China Département de Physique Nucléaire et Corpusculaire Facultéde SciencesUniversitéde Genève24 Quai Ernest Ansermet1211 GenevaSwitzerland Institute of Frontier and Interdisciplinary Science Shandong UniversityQingdao 266237China APC Universit'e Paris Cit'eCNRS/IN2P3CEA/IRFUObservat

The full array of the Large High Altitude Air Shower Observatory(LHAASO)has been in operation since July *** its kilometer-square array(KM2A),we optimized the selection criteria for very high and ultrahigh energyγ-rays using data collected from August 2021 to August 2022,resulting in an improvement in significance of the detection in the Crab Nebula of approximately 15%,compared with that of previous *** the implementation of these new selection criteria,the angular resolution was also significantly improved by approximately 10%at tens of *** aspects of the full KM2A array performance,such as the pointing error,were also calibrated using the Crab *** resulting energy spectrum of the Crab Nebula in the energy range of 10-1000 TeV are well fitted by a log-parabola model,which is consistent with the previous results from LHAASO and other experiments.

关键词： γ-ray Crab Nebula significance

Compressive property and energy absorption characteristic of interconnected porous Mg-zn-Y alloys with adjusting Y addition

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Journal of Magnesium and Alloys 2024年第1期12卷 171-185页

作者： J.A.Liu S.J.Liu b.Wang W.b.sun X.J.Liu z.W.Han College of Materials Science and Engineering Key Laboratory of Automobile Materials(Ministry of Education)Jilin UniversityChangchun 130022PR China Key Laboratory of bionic Engineering(Ministry of Education) College of Biological and Agricultural EngineeringJilin UniversityChangchun130022PR China Weihai Institute for bionics-Jilin University Weihai 264205PR China

In this study,interconnected porous Mg-2zn-xY alloys with different phase compositions were prepared by various Y additions(x=0.4,3,and 6 wt.%)to adjust the compressive properties and energy absorption *** characterization methods were then applied to identify the microstructure of the porous Mg-zn-Y and describe the details of the second *** tests were performed at room temperature(RT),200℃,and 300℃to study the impact of the Y addition and testing temperature on the compressive properties of the porous *** experimental results showed that a high Y content promotes a microstructure refinement and increases the volume fraction of the second *** the Y content increases,different Mg-zn-Y ternary phases appear:I-phase(Mg_(3)zn_(6)Y),W-phase(Mg_(3)zn_(3)Y_(2)),and LPSO phase(Mg_(12)znY).When the Y content ranges between 0.4%and 6%,the compressive strength increases from 6.30MPa to 9.23 MPa,and the energy absorption capacity increases from 7.33 MJ/m^(3)to 10.97 MJ/m^(3)at RT,which is mainly attributed to the phase composition and volume fraction of the second ***,the average energy absorption efficiency is independent of the Y *** addition,the compressive deformation behaviors of the porous Mg-zn-Y are altered by the testing *** compressive strength and energy absorption capacity of the porous Mg-zn-Y decrease due to the softening effect of the high temperature on the *** deformation behaviors at different temperatures are finally observed to reflect the failure mechanisms of the struts.

关键词： Porous magnesium Rare earth elements Microstructure Compressive behavior Energy absorption characteristic

Rational molecular design of efficient yellow-red dendrimer TADF for solution-processed OLEDs: a combined effect of substitution position and strength of the donors

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Science China Chemistry 2024年第5期67卷 1613-1623页

作者： Changfeng Si Dianming sun Tomas Matulaitis David b.Cordes Alexandra M.z.Slawin Eli zysman-Colman Organic Semiconductor Centre EaStCHEM School of ChemistryUniversity of St AndrewsSt AndrewsKY169STUK

The development of high-performance solution-processed red organic light-emitting diodes(OLEDs) remains a challenge,particularly in terms of maintaining efficiency at high luminance. Here, we designed and synthesized four novel orange-red thermally activated delayed fluorescence(TADF) dendrimers that are solution-processable: 2GCz bP, 2DPACz bP, 2FbP2GCz and 2FbP2DPACz. We systematically investigated the effect of substitution position and strength of donors on the optoelectronic properties. The reverse intersystem crossing rate constant(kRISC) of the emitters having donors substituted at positions 11and 12 of the dibenzo[a,c]phenazine(bP) is more than 10-times faster than that of compounds substituted having donors substituted at positions 3 and 6. Compound 2DPACz bP, containing stronger donors than 2GCz bP, exhibits a red-shifted emission and smaller singlet-triplet energy splitting, ΔE_(ST), of 0.01 e V. The solution-processed OLED with 10 wt% 2DPACz bP doped in m CP emitted at 640 nm and showed a maximum external quantum efficiency(EQE_(max)) of 7.8%, which was effectively maintained out to a luminance of 1,000 cd m-2. Such a device's performance at relevant display luminance is among the highest for solution-processed red TADF OLEDs. The efficiency of the devices was improved significantly by using 4Cz IPN as an assistant dopant in a hyperfluorescence(HF) configuration, where the 2DPACz bP HF device shows an EQEmaxof 20.0% at λEL of 605 nm and remains high at 11.8% at a luminance of 1,000 cd m-2, which makes this device one of the highest efficiency orange-to-red HF SP-OLEDs to date.

关键词： thermally activated delayed fluorescence solution-processing red OLEDs dibenzo[a,c]phenazine dendrimers

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A Novel Design and Fabrication of Magnetic Random Access Memory based on Nano-ring-type Magnetic Tunnel Junctions

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Journal of Materials Science & Technology 2007年第3期23卷 304-306页

作者： X.F.Han H.X.Wei z.L.Peng H.D.Yang J.F.Feng G.X.Du z.b.sun L.X.Jiang Q.H.Qin M.Ma Y.Wang z.C.Wen D.P.Liu W.S.zhan State Key Laboratory of Magnetism Beijing National Laboratory for Condensed Matter Physics Institute of Physics Chinese Academy of Science Beijing 100080 China

Nano-ring-type magnetic tunnel junctions （NR-MTJs） with the layer structure of Ta（5）/Ir22Mn78（10）/ Co75Fe25（2）/Ru（0.75）/CoooFe20b20（3）/Al（0.6）-oxide/Co60Fe20b20（2.5）/Ta（3）/Ru（5）（thickness unit： nm） were nano-fabricated on the Si（100）/SiO2 substrate using magnetron sputtering deposition combined with the optical lithography, electron beam lithography （EbL） and Ar ion-beam etching techniques. The smaller NR-MTJs with the inner- and outer-diameter of around 50 and 100 nm and also their corresponding NR-MTJ arrays were nano-patterned. The tunnelling magnetoresistance （TMR ＆ R） versus driving current （I） loops for a spin-polarized current switching were measured, and the TMR ratio of around 35% at room temperature were observed. The critical values of switching current for the free Co60Fe20b20 layer relative to the reference Co6oFe2ob2o layer between parallel and anti-parallel magnetization states were between 0.50 and 0.75 mA in such NR-MTJs. It is suggested that the applicable MRAM fabrication with the density and capacity higher than 256 Mbit/inch2 even 6 Gbite/inch2 are possible using both I NR-MTJ＋1 transistor structure and current switching mechanism based on based on our fabricated 4×4 MRAM demo devices.

关键词： Nano-ring-type magnetic tunnel junctions NR-MTJ MRAM spin polarization Spin transfer effect

Probing the bardeen-Kiselev black hole with the cosmological constant caused by Einstein equations coupled with nonlinear electrodynamics using quasinormal modes and greybody bounds

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Communications in Theoretical Physics 2024年第6期76卷 102-119页

作者： S R Wu b Q Wang z W Long College of Physics Guizhou UniversityGuiyang 550025China College Pharmacy Guizhou University of Traditional Chinese MedicineGuiyang 550025China

In this work,we investigate a static and spherically symmetric bardeen-Kiselev black hole(bH)with the cosmological constant,which is a solution of the Einstein-non-linear Maxwell field *** compute the quasinormal frequencies for the bardeen-Kiselev bH with the cosmological constant due to electromagnetic and gravitational *** varying the bH parameters,we discuss the behavior of both real and imaginary parts of the bH quasinormal frequencies and compare these frequencies with the Reissner-Nordström-de Sitter bH surrounded by quintessence(RN-dSQ).Interestingly,it is shown that the responses of the bardeen-Kiselev bH with the cosmological constant and the RN-dSQ under electromagnetic perturbations are different when the charge parameter q,the state parameter w and the normalization factor c are varied;however,for the gravitational perturbations,the responses of the bardeen-Kiselev bH with the cosmological constant and the RN-dSQ are different only when the charge parameter q is ***,compared with the gravitational perturbations,the electromagnetic perturbations can be used to understand nonlinear and linear electromagnetic fields in curved spacetime *** interesting observation is that,due to the presence of Kiselev quintessence,the electromagnetic perturbations around the bardeen-Kiselev bH with the cosmological constant damps faster and oscillates slowly;for the gravitational perturbations,the quasinormal mode decays slowly and oscillates *** also study the reflection and transmission coefficients along with the absorption cross section in the bardeen-Kiselev bH with the cosmological constant;it is shown that the transmission coefficients will increase due to the presence of Kiselev quintessence.

关键词： quasinormal modes greybody factors bardeen-Kiselev black hole with cosmological constant

Air purifier or fresh air system? A comparison of energy consumption and cost in urban China residential buildings

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Science China Technological Sciences 2024年第9期67卷 2637-2647页

作者： GUO Yong sun zhiWei WESCHLER Louise b. zHANG YinPing Department of building Science Tsinghua University beijing Key Laboratory of Indoor Air Quality Evaluation and Control Independent Researcher

Chinese urban residential buildings face serious indoor air quality problems. Air purification systems(e.g., air purifiers, fresh air systems) that supply fresh air or purify indoor air are widely used in residential buildings to improve indoor air *** the challenges of energy conservation and emission reduction, it is urgent to guide residents on choosing appropriate air purification systems. The key problem is how to identify the best air purification system with the lowest energy consumption or operating cost. Comparisons of air purification systems have rarely been conducted on the premise that they should deliver air such that the main indoor pollutant concentrations all meet air quality standards. Also ignored in comparisons are the increased filtration resistance caused by dust accumulation on the filter and the cost of filter replacement. In this study, we propose a method to compare residential air purification systems based on energy consumption and total cost, and we provide methods to select air purification systems in China's different climatic regions. We used a standard two-person bedroom as the example, and determined the most suitable(minimum cost or energy consumption) air purification systems for the capital cities of the provinces in Chinese mainland.

关键词： IAQ fresh air system air purifier energy consumption cost

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Exploring Variability in Sea Level at a Tide Gauge Station through Control Charts

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Journal of Environmental & Earth Sciences 2024年第1期6卷 11-18页

作者： H.bâkiİz Independent Scholar Boca Raton Florida33496USA

Monitoring temporal changes in sea level is important in assessing coastal *** level anomalies at a tide gauge station,if kinematically conceived,include systematic variations such as trend,acceleration,periodic oscillations,and random *** them,the non-stationary nature of the random sea level variations of known or unknown origin at coastal regions has been long recognized by the sea level *** study proposes the analyses of subgroups of random residual statistics of a rigorously formulated kinematic model solution of tide gauge variations using X-bar and S control *** approach is demonstrated using Key West,Florida tide gauge *** mean and standard errors of 5-year-long subgroups of the residuals revealed that sea level changes at this location have been progressively intensifying from 1913 to the *** oscillations in sea level at this locality may be attributed partly to the thermal expansion of seawater with increasing temperatures causing larger buoyancy-related sea level fluctuations as well as the intensification of atmospheric events including wind patterns and the impact of changes in inverted barometer effects that will alter coastal risk assessments for the future.

关键词： Climate change Sea level variance X-bar S control charts

Degeneration of foundation cushion species induced by ecological constraints can cause massive changes in alpine plant communities

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Science China(Life Sciences) 2024年第4期67卷 789-802页

作者： Jianguo Chen Xufang Chen Lishen Qian Yazhou zhang bo Li Honghua Shi Lu sun Christian Schöb Hang sun Key Laboratory for Plant Diversity and biogeography of East Asia Kunming Institute of BotanyChinese Academy of SciencesKunming 650201China University of Chinese Academy of Sciences Beijing 100049China College of Resources and Environment Yunnan Agricultural UniversityKunming 650500China Área de biodiversidad y Conservación Universidad Rey Juan CarlosMóstoles 28933Spain

Foundational cushion plants can re-organize community structures and sustain a prominent proportion of alpine biodiversity,but they are sensitive to climate *** loss of cushion species can have broad consequences for associated *** potential plant community changes with the population dynamics of cushion plants remain,however,*** eight plant communities along a climatic and community successional gradient,we assessed cushion population dynamics,the underlying ecological constraints and hence associated plant community changes in alpine communities dominated by the foundational cushion plant Arenaria *** population dynamics of Arenaria are attributed to ecological constraints at a series of life history *** functions are constrained by increasing associated beneficiary plants;subsequent seedling establishment is constrained by temperature,water and light availability,extreme climate events,and interspecific competition;strong competitive exclusion may accelerate mortality and degeneration of cushion *** with cushion dynamics,species composition,abundance and community structure gradually *** cushion plants completely degenerate,previously cushion-dominated communities shift to relatively stable communities that are overwhelmingly dominated by *** warming may accelerate the degeneration process of *** of this foundational cushion plant will possibly induce massive changes in alpine plant communities and hence ecosystem functions in alpine *** assessment of the population dynamics of foundation species is critical for an effective conservation of alpine biodiversity.

关键词： alpine ecosystem biodiversity change climate change plant community dynamics foundation species global warming population dynamics

What diameter?What height?Influence of measures of average tree size on area-based allometric volume relationships

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Forest Ecosystems 2024年第1期11卷 100-109页

作者： Yilin Wang John A.Kershaw Mark J.Ducey Yuan sun James b.McCarter Integrated Forest Mensuration and Systems Analysis Laboratory Faculty of Forestry and Environmental ManagementUniversity of New BrunswickFrederictonNBCanada Department of Natural Resources and the Environment University of New HampshireDurhamNHUSA College of Forestry Nanjing Forestry UniversityNanjing210037China Scientific Programmer RayonierYuleeFLUSA

Volume is an important attribute used in many forest management *** from 83 fixed-area plots located in central New brunswick,Canada,are used to examine how different measures of stand-level diameter and height influence volume prediction using a stand-level variant of Honer's(1967)volume *** density was included in the models(Volume=f(Diameter,Height,Density))choice of diameter measure was more important than choice of height *** density was not included(Volume=f(Diameter,Height)),the opposite was *** models with density included,moment-based estimators of stand diameter and height performed better than all other *** models without density,largest tree estimators of stand diameter and height performed better than other *** overall best equation used quadratic mean diameter,Lorey's height,and density(root mean square error=5.26 m^3·ha^(-1);1.9%relative error).The best equation without density used mean diameter of the largest trees needed to calculate a stand density index of 400 and the mean height of the tallest 400 trees per ha(root mean square error=32.08 m^(3)·ha^(-1);11.8%relative error).The results of this study have some important implications for height subsampling and LiDAR-derived forest inventory analyses.

关键词： Allometric relationships Stand structure Volume estimation Stand-level attributes