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Investigation of bubbles escape behavior from low basicity mold flux for high-Mn high-Al steels using 3D X-ray microscope
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作者 Qiang Liu Xiang Li +3 位作者 Shen Du Ming Gao Yanbin Yin Jiongming Zhang 《International Journal of Minerals,Metallurgy and Materials》 SCIE EI CAS 2025年第1期102-110,共9页
During the continuous casting process of high-Mn high-Al steels,various types of gases such as Ar need to escape through the top of the mold.In which,the behavior of bubbles traversing the liquid slag serves as a rest... During the continuous casting process of high-Mn high-Al steels,various types of gases such as Ar need to escape through the top of the mold.In which,the behavior of bubbles traversing the liquid slag serves as a restrictive link,closely associated with viscosity and the thickness of liquid slag.In contrast to two-dimensional surface observation,three-dimensional(3D)analysis method can offer a more intuitive,accurate,and comprehensive information.Therefore,this study employs a 3D X-ray microscope(3D-XRM)to obtained spatial distribution and 3D morphological characteristics of residual bubbles in mold flux under different basicity of liquid slag,different temperatures,and different holding times.The results indicate that as basicity of slag increases from 0.52 to 1.03,temperature increases from 1423 to 1573 K,the viscosity of slag decreases,the floating rate of bubbles increases.In addition,when holding time increases from 10 to 30 s,the bubbles floating distance increases,and the volume fraction and average equivalent sphere diameter of the bubbles solidified in the mold flux gradually decreases.In one word,increasing the basicity,temperature,and holding time leading to an increase in the removal rate of bubbles especially for the large.These findings of bubbles escape behavior provide valuable insights into optimizing low basicity mold flux for high-Mn high-Al steels. 展开更多
关键词 mold flux low basicity BUBBLES three-dimensional x-ray microscope VISCOSITY
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Development of a seven-cell S-band standing-wave RF-deflecting cavity for Tsinghua Thomson scattering X-ray source 被引量:1
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作者 Xian-Cai Lin Hao Zha +4 位作者 Jia-Ru Shi Liu-Yuan Zhou Shuang Liu Jian Gao Huai-Bi Chen 《Nuclear Science and Techniques》 SCIE EI CAS CSCD 2021年第4期20-29,共10页
A 2856-MHz,π-mode,seven-cell standingwave deflecting cavity was designed and fabricated for bunch length measurement in Tsinghua Thomson scattering X-ray source(TTX)facility.This cavity was installed in the TTX and p... A 2856-MHz,π-mode,seven-cell standingwave deflecting cavity was designed and fabricated for bunch length measurement in Tsinghua Thomson scattering X-ray source(TTX)facility.This cavity was installed in the TTX and provided a deflecting voltage of 4.2 MV with an input power of 2.5 MW.Bunch length diagnoses of electron beams with energies up to 39 MeV have been performed.In this article,the RF design of the cavity using HFSS,fabrication,and RF test processes are reviewed.High-power operation with accelerated beams and calibration of the deflecting voltage are also presented. 展开更多
关键词 Deflecting RF cavity Standing wave Bunchlength measurement Thomson x-ray source
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Optimization of the cavity beam-position monitor system for the Shanghai soft X-ray free-electron laser user facility 被引量:3
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作者 Jian Chen Yong-Bin Leng +2 位作者 Lu-Yang Yu Long-Wei Lai Ren-Xian Yuan 《Nuclear Science and Techniques》 SCIE EI CAS CSCD 2022年第10期22-32,共11页
To achieve high-efficiency operation of the highgain free-electron laser(FEL),the electron beams and radiated photon beams need to be overlapped precisely and pass through the entire undulator section.Therefore,a high... To achieve high-efficiency operation of the highgain free-electron laser(FEL),the electron beams and radiated photon beams need to be overlapped precisely and pass through the entire undulator section.Therefore,a high-resolution beam-position monitor(BPM)is required.A cavity BPM(CBPM)with a resonant cavity structure was developed and used in the Shanghai Soft X-ray FEL(SXFEL)test facility and can achieve a position resolution of<1μm.The construction and operation of the SXFEL user facility also bring about higher requirements for beamposition measurement.In this case,the factors that affect the performance of the CBPM system were further analyzed.These included the amplitude and phase stability of the local oscillator,stability of the trigger signal,performance of the radio frequency front-end,signal processing electronics,and signal processing algorithms.Based on the upgrade and optimization of the system,a beam test platform was built at the end of the linear acceleration section of the SXFEL,and the experimental results show that the position resolution of the system can reach 177 nm at a bunch charge of 500 pC,and the dynamic range is controlled within±300μm,and the relative measurement uncertainty of the bunch charge can reach 0.021%,which are significant improvements compared to the attributes of the previous system. 展开更多
关键词 cavity BPM SXFEL System optimization Position resolution Measurement uncertainty ALGORITHM
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M^(3)Res-Transformer:新冠肺炎胸部X-ray图像识别模型 被引量:1
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作者 周涛 刘赟璨 +3 位作者 侯森宝 常晓玉 叶鑫宇 陆惠玲 《电子学报》 EI CAS CSCD 北大核心 2024年第2期589-601,共13页
新冠肺炎(COVID-19)自爆发以来严重影响人类生命健康,近年来残差神经网络广泛应用于COVID-19识别任务中,辅助医生快速地诊断COVID-19患者,但是COVID-19图像病变区域形状复杂、大小不一,与周围组织的边界模糊,导致网络难以提取有效特征.... 新冠肺炎(COVID-19)自爆发以来严重影响人类生命健康,近年来残差神经网络广泛应用于COVID-19识别任务中,辅助医生快速地诊断COVID-19患者,但是COVID-19图像病变区域形状复杂、大小不一,与周围组织的边界模糊,导致网络难以提取有效特征.本文针对上述问题,提出一种M^(3)Res-Transformer的新冠肺炎胸部X-ray图像识别模型,采用Res-Transformer作为模型的主干网络,结合ResNet和ViT,有效地整合局部病变特征和全局特征;设计混合残差注意力模块(mixed residual attention Module,mraM),同时考虑通道和空间位置的相互依赖性,增强网络的特征表达能力;为了增大感受野,提取多尺度特征,通过叠加具有不同扩张率的扩张卷积构造多尺度扩张残差模块(multiscale dilated residual Module,mdrM),根据不同层次特征尺度的差异,使用3个逐渐收缩尺度的mdrM进行多尺度特征提取;提出上下文交叉感知模块(contextual cross-awareness Module,ccaM),使用深层特征中的语义信息来引导浅层特征,然后将浅层特征中的空间信息嵌入深层特征中,采用交叉加权注意力机制高效聚合深层和浅层特征,获得更丰富的上下文信息.为了验证本文所提模型的有效性,在新冠肺炎胸部X-ray图像数据集上进行实验,与先进的CNN分类模型、融合不同注意力机制的ResNet50模型、基于Transformer的分类模型对比以及消融实验.结果表明,本文所提模型的Acc、Pre、Rec、F1-Score与Spe指标分别为96.33%、96.36%、96.33%、96.35%与96.26%,在COVID-19胸部X-ray图像识别任务中有效提升了识别精度,并通过可视化方法对其进行进一步验证,为COVID-19的辅助诊断提供重要的参考价值. 展开更多
关键词 COVID-19 胸部x-ray图像 残差神经网络 vision transformer 注意力机制
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X-ray在鱼体组织及微量元素检测中的应用
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作者 宋一帆 张胜茂 +4 位作者 张衡 唐峰华 张寒野 石永闯 崔雪森 《应用光学》 CAS 北大核心 2024年第1期166-176,共11页
鱼类硬质组织物,特别是骨骼支持鱼体和保护其体内器官的组织,对其进行特征检测分析是研究鱼类游泳运动、鱼类解剖、鱼体建模等的数据基础。随着X-ray技术的发展和国产设备的广泛应用,其仪器设备成本明显降低,使得X-ray在渔业研究与自动... 鱼类硬质组织物,特别是骨骼支持鱼体和保护其体内器官的组织,对其进行特征检测分析是研究鱼类游泳运动、鱼类解剖、鱼体建模等的数据基础。随着X-ray技术的发展和国产设备的广泛应用,其仪器设备成本明显降低,使得X-ray在渔业研究与自动化生产中的应用成为可能。首先介绍了X-ray技术的基本原理与其在鱼体组织检测中的应用,X-ray技术在鱼体组织及微量元素检测中的应用主要分为鱼类组织器官的无损检测和鱼体微量元素检测两部分,其中分别介绍了包括照相法、数字成像法、衍射技术和吸收光谱法等X-ray技术;然后综述其在鱼体组织器官建模、鱼骨检测、鱼类化石研究、鱼耳石分析和鱼体微量元素检测方面的应用,总结了Xray在渔业领域应用中存在的问题;最后对X-ray的渔业应用方向进行展望。 展开更多
关键词 x-ray 鱼体骨骼 鱼类耳石 鱼体建模 鱼体微量元素
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Global hybrid simulations of soft X-ray emissions in the Earth’s magnetosheath 被引量:2
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作者 Jin Guo TianRan Sun +6 位作者 San Lu QuanMing Lu Yu Lin XueYi Wang Chi Wang RongSheng Wang Kai Huang 《Earth and Planetary Physics》 EI CSCD 2024年第1期47-58,共12页
Earth’s magnetopause is a thin boundary separating the shocked solar wind plasma from the magnetospheric plasmas,and it is also the boundary of the solar wind energy transport to the magnetosphere.Soft X-ray imaging ... Earth’s magnetopause is a thin boundary separating the shocked solar wind plasma from the magnetospheric plasmas,and it is also the boundary of the solar wind energy transport to the magnetosphere.Soft X-ray imaging allows investigation of the large-scale magnetopause by providing a two-dimensional(2-D)global view from a satellite.By performing 3-D global hybrid-particle-in-cell(hybrid-PIC)simulations,we obtain soft X-ray images of Earth’s magnetopause under different solar wind conditions,such as different plasma densities and directions of the southward interplanetary magnetic field.In all cases,magnetic reconnection occurs at low latitude magnetopause.The soft X-ray images observed by a hypothetical satellite are shown,with all of the following identified:the boundary of the magnetopause,the cusps,and the magnetosheath.Local X-ray emissivity in the magnetosheath is characterized by large amplitude fluctuations(up to 160%);however,the maximum line-of-sight-integrated X-ray intensity matches the tangent directions of the magnetopause well,indicating that these fluctuations have limited impact on identifying the magnetopause boundary in the X-ray images.Moreover,the magnetopause boundary can be identified using multiple viewing geometries.We also find that solar wind conditions have little effect on the magnetopause identification.The Solar wind Magnetosphere Ionosphere Link Explorer(SMILE)mission will provide X-ray images of the magnetopause for the first time,and our global hybrid-PIC simulation results can help better understand the 2-D X-ray images of the magnetopause from a 3-D perspective,with particle kinetic effects considered. 展开更多
关键词 MAGNETOPAUSE x-ray emissivity x-ray imaging SMILE global hybrid-PIC simulation
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The Soft X-ray Imager(SXI)on the SMILE Mission 被引量:4
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作者 S.Sembay A.L.Alme +83 位作者 D.Agnolon T.Arnold A.Beardmore A.Belén Balado Margeli C.Bicknell C.Bouldin G.Branduardi-Raymont T.Crawford J.P.Breuer T.Buggey G.Butcher R.Canchal J.A.Carter A.Cheney Y.Collado-Vega H.Connor T.Crawford N.Eaton C.Feldman C.Forsyth T.Frantzen G.Galgóczi J.Garcia G.Y.Genov C.Gordillo H-P.Gröbelbauer M.Guedel Y.Guo M.Hailey D.Hall R.Hampson J.Hasiba O.Hetherington A.Holland S-Y.Hsieh M.W.J.Hubbard H.Jeszenszky M.Jones T.Kennedy K.Koch-Mehrin S.Kögl S.Krucker K.D.Kuntz C.Lakin G.Laky O.Lylund A.Martindale J.Miguel Mas Hesse R.Nakamura K.Oksavik N.Østgaard H.Ottacher R.Ottensamer C.Pagani S.Parsons P.Patel J.Pearson G.Peikert F.S.Porter T.Pouliantis B.H.Qureshi W.Raab G.Randal A.M.Read N.M.M.Roque M.E.Rostad C.Runciman S.Sachdev A.Samsonov M.Soman D.Sibeck S.Smit J.Søndergaard R.Speight S.Stavland M.Steller TianRan Sun J.Thornhill W.Thomas K.Ullaland B.Walsh D.Walton C.Wang S.Yang 《Earth and Planetary Physics》 EI CSCD 2024年第1期5-14,共10页
The Soft X-ray Imager(SXI)is part of the scientific payload of the Solar wind Magnetosphere Ionosphere Link Explorer(SMILE)mission.SMILE is a joint science mission between the European Space Agency(ESA)and the Chinese... The Soft X-ray Imager(SXI)is part of the scientific payload of the Solar wind Magnetosphere Ionosphere Link Explorer(SMILE)mission.SMILE is a joint science mission between the European Space Agency(ESA)and the Chinese Academy of Sciences(CAS)and is due for launch in 2025.SXI is a compact X-ray telescope with a wide field-of-view(FOV)capable of encompassing large portions of Earth’s magnetosphere from the vantage point of the SMILE orbit.SXI is sensitive to the soft X-rays produced by the Solar Wind Charge eXchange(SWCX)process produced when heavy ions of solar wind origin interact with neutral particles in Earth’s exosphere.SWCX provides a mechanism for boundary detection within the magnetosphere,such as the position of Earth’s magnetopause,because the solar wind heavy ions have a very low density in regions of closed magnetic field lines.The sensitivity of the SXI is such that it can potentially track movements of the magnetopause on timescales of a few minutes and the orbit of SMILE will enable such movements to be tracked for segments lasting many hours.SXI is led by the University of Leicester in the United Kingdom(UK)with collaborating organisations on hardware,software and science support within the UK,Europe,China and the United States. 展开更多
关键词 Soft x-ray Imaging micropore optics large area CCD
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Two methods for separating the magnetospheric solar wind charge exchange soft X-ray emission from the diffuse X-ray background 被引量:2
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作者 YingJie Zhang TianRan Sun +5 位作者 JenniferACarter WenHao Liu Steve Sembay ShuiNai Zhang Li Ji Chi Wang 《Earth and Planetary Physics》 EI CSCD 2024年第1期119-132,共14页
Solar wind charge exchange(SWCX)is the process of solar wind high-valence ions exchanging charges with neutral components and generating soft X-rays.Recently,detecting the SWCX emission from the magnetosphere is propo... Solar wind charge exchange(SWCX)is the process of solar wind high-valence ions exchanging charges with neutral components and generating soft X-rays.Recently,detecting the SWCX emission from the magnetosphere is proposed as a new technique to study the magnetosphere using panoramic soft X-ray imaging.To better prepare for the data analysis of upcoming magnetospheric soft X-ray imaging missions,this paper compares the magnetospheric SWCX emission obtained by two methods in an XMM-Newton observation,during which the solar wind changed dramatically.The two methods differ in the data used to fit the diffuse X-ray background(DXB)parameters in spectral analysis.The method adding data from the ROSAT All-Sky Survey(RASS)is called the RASS method.The method using the quiet observation data is called the Quiet method,where quiet observations usually refer to observations made by the same satellite with the same target but under weaker solar wind conditions.Results show that the spectral compositions of magnetospheric SWCX emission obtained by the two methods are very similar,and the changes in intensity over time are highly consistent,although the intensity obtained by the RASS method is about 2.68±0.56 keV cm^(-2)s^(-1)sr^(-1)higher than that obtained by the Quiet method.Since the DXB intensity obtained by the RASS method is about 2.84±0.74 keV cm^(-2)s^(-1)sr^(-1)lower than that obtained by the Quiet method,and the linear correlation coefficient between the difference of SWCX and DXB obtained by the two methods in diffe rent energy band is close to-1,the diffe rences in magnetospheric SWCX can be fully attributed to the diffe rences in the fitted DXB.The difference between the two methods is most significant when the energy is less than 0.7 keV,which is also the main energy band of SWCX emission.In addition,the difference between the two methods is not related to the SWCX intensity and,to some extent,to solar wind conditions,because SWCX intensity typically va ries with the solar wind.In summary,both methods are robust and reliable,and should be considered based on the best available options. 展开更多
关键词 solar wind charge exchange(SWCX) ROSAT All-Sky Survey(RASS) soft x-ray x-ray imaging MAGNETOSPHERE
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Exploring battery material failure mechanisms through synchrotron X-ray characterization techniques 被引量:1
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作者 Lingzhe Fang Xiaozhao Liu Tao Li 《Journal of Energy Chemistry》 SCIE EI CAS CSCD 2024年第7期128-135,共8页
Rechargeable battery cycling performance and related safety have been persistent concerns.It is crucial to decipher the capacity fading induced by electrode material failure via a range of techniques.Among these,synch... Rechargeable battery cycling performance and related safety have been persistent concerns.It is crucial to decipher the capacity fading induced by electrode material failure via a range of techniques.Among these,synchrotron-based X-ray techniques with high flux and brightness play a key role in understanding degradation mechanisms.In this comprehensive review,we summarize recent advancements in degra-dation modes and mechanisms that were revealed by synchrotron X-ray methodologies.Subsequently,an overview of X-ray absorption spectroscopy and X-ray scattering techniques is introduced for charac-terizing failure phenomena at local coordination atomic environment and long-range order crystal struc-ture scale,respectively.At last,we envision the future of exploring material failure mechanism. 展开更多
关键词 Battery failure Synchrotron-based techniques x-ray scattering x-ray absorption spectroscopy
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Exotic parrots breeding in urban tree cavities: nesting requirements, geographic distribution, and potential impacts on cavity nesting birds in southeast Florida
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作者 Joshua M.Diamond Michael S.Ross 《Avian Research》 CSCD 2019年第4期459-468,共10页
Background:Exotic parrots have established breeding populations in southeast Florida,including several species that nest in tree cavities.We aimed to determine the species identity,nest site requirements,relative nest... Background:Exotic parrots have established breeding populations in southeast Florida,including several species that nest in tree cavities.We aimed to determine the species identity,nest site requirements,relative nest abundance,geographic distribution,and interactions of parrots with native cavity-nesting bird species.Methods:We searched Miami-Dade County,Florida,and nearby areas for natural cavities and holes excavated by woodpeckers,recording attributes of potential nest trees.We inspected all cavities with an elevated video inspection system to determine occupancy by parrots or other birds.We mapped nearly 4000 citizen science observations of parrots in our study area corresponding to our study period,and used these to construct range maps,comparing them to our nesting observations.Results:Not all parrots reported or observed in our study area were actively breeding.Some parrots were observed at tree cavities,which previous studies have suggested is evidence of reproduction,but our inspections with an elevated video inspection system suggest they never initiated nesting attempts.Several parrot species did successfully nest in tree cavities,Red-masked Parakeets(Psittacara erythrogenys)and Orange-winged Parrots(Amazona amazonica)being the most common(n=7 and 6 nests,respectively).These two parrots had similar nesting requirements,but Orange-winged Parrots use nests with larger entrance holes,which they often enlarge.Geographic analysis of nests combined with citizen science data indicate that parrots are limited to developed areas.The most common parrots were less abundant cavity nesters than the native birds which persist in Miami’s urban areas,and far less abundant than the invasive European Starling(Sturnus vulgaris).Conclusions:Exotic parrots breeding elsewhere in the world have harmed native cavity-nesting birds through interference competition,but competitive interference in southeast Florida is minimized by the urban affinities of parrots in this region.The relative abundance and geographic distribution suggest that these parrots are unlikely to invade adjacent wilderness areas. 展开更多
关键词 Amazona cavity nest webs Invasive species Parakeets Psittacara Urban ecology
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Finding the magnetopause location using soft X-ray observations and a statistical inverse method 被引量:1
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作者 Gonzalo Cucho-Padin Hyunju Connor +2 位作者 Jaewoong Jung Brian Walsh David G.Sibeck 《Earth and Planetary Physics》 EI CSCD 2024年第1期184-203,共20页
Variability in the location and shape of the dayside magnetopause is attributed to magnetic reconnection,a fundamental process that enables the transfer of mass,energy,and momentum from the solar wind into the magneto... Variability in the location and shape of the dayside magnetopause is attributed to magnetic reconnection,a fundamental process that enables the transfer of mass,energy,and momentum from the solar wind into the magnetosphere.The spatial and temporal properties of the magnetopause,under varying solar and magnetospheric conditions,remain largely unknown because empirical studies using in-situ observations are challenging to interpret.Global wide field-of-view(FOV)imaging is the only means to simultaneously observe the spatial distribution of the plasma properties over the vast dayside magnetospheric region and,subsequently,quantify the energy transport from the interplanetary medium into the terrestrial magnetosphere.Two upcoming missions,ESA/CAS SMILE and NASA’s LEXI will provide wide-field imagery of the dayside magnetosheath in soft X-rays,an emission generated by charge exchange interactions between high charge-state heavy ions of solar wind origin and exospheric neutral atoms.High-cadence two-dimensional observations of the magnetosheath will allow the estimation of dynamic properties of its inner boundary,the magnetopause,and enable studies of its response to changes in the solar wind dynamic pressure and interplanetary magnetic field orientation.This work introduces a statistically-based estimation approach based on inverse theory to estimate the spatial distribution of magnetosheath soft X-ray emissivities and,with this,identify the location of the magnetopause over the Sun−Earth line.To do so,we simulate the magnetosheath structure using the MHD-based OpenGGCM model and generate synthetic soft X-ray images using LEXI’s orbit and attitude information.Our results show that 3-D estimations using the described statistically-based technique are robust against Poisson-distributed shot noise inherent to soft X-ray images.Also,our proposed methodology shows that the accuracy of both three-dimensional(3-D)estimation and the magnetopause standoff distance calculation highly depends on the observational point. 展开更多
关键词 MAGNETOPAUSE soft x-ray TOMOGRAPHY
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Estimating the subsolar magnetopause position from soft X-ray images using a low-pass image filter 被引量:1
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作者 Hyangpyo Kim Hyunju K.Connor +9 位作者 Jaewoong Jung Brian M.Walsh David Sibeck Kip D.Kuntz Frederick S.Porter Catriana K.Paw U Rousseau A.Nutter Ramiz Qudsi Rumi Nakamura Michael Collier 《Earth and Planetary Physics》 EI CSCD 2024年第1期173-183,共11页
The Lunar Environment heliospheric X-ray Imager(LEXI)and Solar wind Magnetosphere Ionosphere Link Explorer(SMILE)missions will image the Earth’s dayside magneto pause and cusps in soft X-rays after their respective l... The Lunar Environment heliospheric X-ray Imager(LEXI)and Solar wind Magnetosphere Ionosphere Link Explorer(SMILE)missions will image the Earth’s dayside magneto pause and cusps in soft X-rays after their respective launches in the near future,to specify glo bal magnetic reconnection modes for varying solar wind conditions.To suppo rt the success of these scientific missions,it is critical to develop techniques that extract the magnetopause locations from the observed soft X-ray images.In this research,we introduce a new geometric equation that calculates the subsolar magnetopause position(RS)from a satellite position,the look direction of the instrument,and the angle at which the X-ray emission is maximized.Two assumptions are used in this method:(1)The look direction where soft X-ray emissions are maximized lies tangent to the magnetopause,and(2)the magnetopause surface near the subsolar point is almost spherical and thus RSis nea rly equal to the radius of the magneto pause curvature.We create synthetic soft X-ray images by using the Open Geospace General Circulation Model(OpenGGCM)global magnetohydrodynamic model,the galactic background,the instrument point spread function,and Poisson noise.We then apply the fast Fourier transform and Gaussian low-pass filte rs to the synthetic images to re move noise and obtain accurate look angles for the soft X-ray pea ks.From the filte red images,we calculate RS and its accuracy for different LEXI locations,look directions,and solar wind densities by using the OpenGGCM subsolar magnetopause location as ground truth.Our method estimates RS with an accuracy of<0.3 RE when the solar wind density exceeds>10 cm-3.The accuracy improves for greater solar wind densities and during southward interplanetary magnetic fields.The method ca ptures the magnetopause motion during southwa rd interplaneta ry magnetic field turnings.Consequently,the technique will enable quantitative analysis of the magnetopause motion and help reveal the dayside reconnection modes for dynamic solar wind conditions.This technique will suppo rt the LEXI and SMILE missions in achieving their scientific o bjectives. 展开更多
关键词 soft x-ray MAGNETOPAUSE RECONNECTION low-pass filter LEXI SMILE
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SMILE soft X-ray Imager flight model CCD370 pre-flight device characterisation 被引量:1
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作者 S.Parsons D.J.Hall +4 位作者 O.Hetherington T.W.Buggey T.Arnold M.W.J.Hubbard A.Holland 《Earth and Planetary Physics》 EI CSCD 2024年第1期25-38,共14页
Throughout the SMILE mission the satellite will be bombarded by radiation which gradually damages the focal plane devices and degrades their performance.In order to understand the changes of the CCD370s within the sof... Throughout the SMILE mission the satellite will be bombarded by radiation which gradually damages the focal plane devices and degrades their performance.In order to understand the changes of the CCD370s within the soft X-ray Imager,an initial characterisation of the devices has been carried out to give a baseline performance level.Three CCDs have been characterised,the two flight devices and the flight spa re.This has been carried out at the Open University in a bespo ke cleanroom measure ment facility.The results show that there is a cluster of bright pixels in the flight spa re which increases in size with tempe rature.However at the nominal ope rating tempe rature(-120℃) it is within the procure ment specifications.Overall,the devices meet the specifications when ope rating at -120℃ in 6 × 6 binned frame transfer science mode.The se rial charge transfer inefficiency degrades with temperature in full frame mode.However any charge losses are recovered when binning/frame transfer is implemented. 展开更多
关键词 CCD soft x-ray imager characterisation SMILE
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Solar wind ion charge state distributions and compound cross sections for solar wind charge exchange X-ray emission 被引量:1
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作者 Dimitra Koutroumpa 《Earth and Planetary Physics》 EI CSCD 2024年第1期105-118,共14页
Solar Wind Charge eXchange X-ray(SWCX) emission in the heliosphere and Ea rth’s exosphere is a hard to avoid signal in soft Xray obse rvations of astrophysical targets.On the other hand,the X-ray imaging possibilitie... Solar Wind Charge eXchange X-ray(SWCX) emission in the heliosphere and Ea rth’s exosphere is a hard to avoid signal in soft Xray obse rvations of astrophysical targets.On the other hand,the X-ray imaging possibilities offered by the SWCX process has led to an increasing number of future dedicated space missions for investigating the solar wind-terrestrial inte ractions and magnetospheric interfaces.In both cases,accurate modelling of the SWCX emission is key to correctly interpret its signal,and remove it from obse rvations,when needed.In this paper,we compile solar wind abundance measurements from ACE for different solar wind types,and atomic data from literature,including charge exchange cross-sections and emission probabilities,used fo r calculating the compound cross-section a for the SWCX X-ray emission.We calculate a values for charge-exchange with H and He,relevant to soft X-ray energy bands(0.1-2.0 keV)for various solar wind types and solar cycle conditions. 展开更多
关键词 solar wind charge exchange x-rays MAGNETOSPHERE HELIOSPHERE
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Web Layout Design of Large Cavity Structures Based on Topology Optimization 被引量:1
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作者 Xiaoqiao Yang Jialiang Sun Dongping Jin 《Computer Modeling in Engineering & Sciences》 SCIE EI 2024年第3期2665-2689,共25页
Large cavity structures are widely employed in aerospace engineering, such as thin-walled cylinders, blades andwings. Enhancing performance of aerial vehicles while reducing manufacturing costs and fuel consumptionhas... Large cavity structures are widely employed in aerospace engineering, such as thin-walled cylinders, blades andwings. Enhancing performance of aerial vehicles while reducing manufacturing costs and fuel consumptionhas become a focal point for contemporary researchers. Therefore, this paper aims to investigate the topologyoptimization of large cavity structures as a means to enhance their performance, safety, and efficiency. By usingthe variable density method, lightweight design is achieved without compromising structural strength. Theoptimization model considers both concentrated and distributed loads, and utilizes techniques like sensitivityfiltering and projection to obtain a robust optimized configuration. The mechanical properties are checked bycomparing the stress distribution and displacement of the unoptimized and optimized structures under the sameload. The results confirm that the optimized structures exhibit improved mechanical properties, thus offering keyinsights for engineering lightweight, high-strength large cavity structures. 展开更多
关键词 Topology optimization lightweight design web layout design cavity structure
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Transferring of a Two-Mode Entangled State Between Two Cavities via Cavity QED
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作者 WU Tao NI Zhi-Xiang YE Liu 《Communications in Theoretical Physics》 SCIE CAS CSCD 2007年第3期451-453,共3页
We propose a scheme for transferring of a two-mode entanglement of zero- or one-photon entangled states between two cavities via atom-cavity field resonant interaction. In our proposal, in order to transfer the entang... We propose a scheme for transferring of a two-mode entanglement of zero- or one-photon entangled states between two cavities via atom-cavity field resonant interaction. In our proposal, in order to transfer the entangled state, we only need two identical two-level atoms and a two-mode cavity for receiving the teleported state. This scheme does not require Bell-state measurement and performing any transformations to reconstruct the initial state. And the transfer can occur with 100% success probability in a simple manner. And a network for transferring of a two-mode entangled state between cavities is suggested. This scheme can also be extended to transfer N-mode entangled state of cavity. 展开更多
关键词 TRANSFER cavity QED quantum entanglement resonant interaction
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Dual-cavity beam arrival time monitor design for the Shanghai soft X-ray FEL facility 被引量:2
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作者 Shan-Shan Cao Ren-Xian Yuan +1 位作者 Jian Chen Yong-Bin Leng 《Nuclear Science and Techniques》 SCIE CAS CSCD 2019年第5期14-21,共8页
Free electron lasers provide high-power and ultrashort pulses with extreme brightness. In order to improve a facility's capabilities and explore the possibility of performing high-resolution time-resolved experime... Free electron lasers provide high-power and ultrashort pulses with extreme brightness. In order to improve a facility's capabilities and explore the possibility of performing high-resolution time-resolved experiments, a beam arrival time resolution under 100 fs is required. In this article, a novel beam arrival time monitor(BAM)equipped with two cavities has been designed and a beam flight time measurement scheme based on the BAM prototype has been proposed to estimate phase jitter in the signal measurement system. The two BAM cavities work at different frequencies and the frequency difference is designed to be 35 MHz. Therefore, a self-mixing intermediate frequency signal can be generated using the two cavities. The measured beam flight time shows a temporal deviation of 37 fs(rms). 展开更多
关键词 BEAM ARRIVAL TIME MONITOR Dual-cavities BEAM flight TIME SELF-MIXING
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Microstructures and micromechanical behaviors of high -entropy alloys investigated by synchrotron X-ray and neutron diffraction techniques: A review 被引量:1
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作者 Yubo Huang Ning Xu +3 位作者 Huaile Lu Yang Ren Shilei Li Yandong Wang 《International Journal of Minerals,Metallurgy and Materials》 SCIE EI CAS CSCD 2024年第6期1333-1349,共17页
High-entropy alloys(HEAs)possess outstanding features such as corrosion resistance,irradiation resistance,and good mechan-ical properties.A few HEAs have found applications in the fields of aerospace and defense.Exten... High-entropy alloys(HEAs)possess outstanding features such as corrosion resistance,irradiation resistance,and good mechan-ical properties.A few HEAs have found applications in the fields of aerospace and defense.Extensive studies on the deformation mech-anisms of HEAs can guide microstructure control and toughness design,which is vital for understanding and studying state-of-the-art structural materials.Synchrotron X-ray and neutron diffraction are necessary techniques for materials science research,especially for in situ coupling of physical/chemical fields and for resolving macro/microcrystallographic information on materials.Recently,several re-searchers have applied synchrotron X-ray and neutron diffraction methods to study the deformation mechanisms,phase transformations,stress behaviors,and in situ processes of HEAs,such as variable-temperature,high-pressure,and hydrogenation processes.In this review,the principles and development of synchrotron X-ray and neutron diffraction are presented,and their applications in the deformation mechanisms of HEAs are discussed.The factors that influence the deformation mechanisms of HEAs are also outlined.This review fo-cuses on the microstructures and micromechanical behaviors during tension/compression or creep/fatigue deformation and the application of synchrotron X-ray and neutron diffraction methods to the characterization of dislocations,stacking faults,twins,phases,and intergrain/interphase stress changes.Perspectives on future developments of synchrotron X-ray and neutron diffraction and on research directions on the deformation mechanisms of novel metals are discussed. 展开更多
关键词 high-entropy alloys MICROSTRUCTURES micromechanical behaviors synchrotron x-ray diffraction neutron diffraction
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Non-volatile dynamically switchable color display via chalcogenide stepwise cavity resonators 被引量:1
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作者 Kuan Liu Zhenyuan Lin +2 位作者 Bing Han Minghui Hong Tun Cao 《Opto-Electronic Advances》 SCIE EI CAS CSCD 2024年第1期16-27,共12页
High-resolution multi-color printing relies upon pixelated optical nanostructures,which is crucial to promote color display by producing nonbleaching colors,yet requires simplicity in fabrication and dynamic switching... High-resolution multi-color printing relies upon pixelated optical nanostructures,which is crucial to promote color display by producing nonbleaching colors,yet requires simplicity in fabrication and dynamic switching.Antimony trisulfide(Sb_(2)S_(3))is a newly rising chalcogenide material that possesses prompt and significant transition of its optical characteristics in the visible region between amorphous and crystalline phases,which holds the key to color-varying devices.Herein,we proposed a dynamically switchable color printing method using Sb_(2)S_(3)-based stepwise pixelated Fabry-Pérot(FP)cavities with various cavity lengths.The device was fabricated by employing a direct laser patterning that is a less timeconsuming,more approachable,and low-cost technique.As switching the state of Sb_(2)S_(3) between amorphous and crystalline,the multi-color of stepwise pixelated FP cavities can be actively changed.The color variation is due to the profound change in the refractive index of Sb_(2)S_(3) over the visible spectrum during its phase transition.Moreover,we directly fabricated sub-50 nm nano-grating on ultrathin Sb_(2)S_(3) laminate via microsphere 800-nm femtosecond laser irradiation in far field.The minimum feature size can be further decreased down to~45 nm(λ/17)by varying the thickness of Sb_(2)S_(3) film.Ultrafast switchable Sb_(2)S_(3) photonic devices can take one step toward the next generation of inkless erasable papers or displays and enable information encryption,camouflaging surfaces,anticounterfeiting,etc.Importantly,our work explores the prospects of rapid and rewritable fabrication of periodic structures with nano-scale resolution and can serve as a guideline for further development of chalcogenide-based photonics components. 展开更多
关键词 TUNABLE color displays Fabry-Pérot cavity resonators color printing chalcogenide materials
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Using restored two-dimensional X-ray images to reconstruct the three-dimensional magnetopause 被引量:2
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作者 RongCong Wang JiaQi Wang +3 位作者 DaLin Li TianRan Sun XiaoDong Peng YiHong Guo 《Earth and Planetary Physics》 EI CSCD 2024年第1期133-154,共22页
Astronomical imaging technologies are basic tools for the exploration of the universe,providing basic data for the research of astronomy and space physics.The Soft X-ray Imager(SXI)carried by the Solar wind Magnetosph... Astronomical imaging technologies are basic tools for the exploration of the universe,providing basic data for the research of astronomy and space physics.The Soft X-ray Imager(SXI)carried by the Solar wind Magnetosphere Ionosphere Link Explorer(SMILE)aims to capture two-dimensional(2-D)images of the Earth’s magnetosheath by using soft X-ray imaging.However,the observed 2-D images are affected by many noise factors,destroying the contained information,which is not conducive to the subsequent reconstruction of the three-dimensional(3-D)structure of the magnetopause.The analysis of SXI-simulated observation images shows that such damage cannot be evaluated with traditional restoration models.This makes it difficult to establish the mapping relationship between SXIsimulated observation images and target images by using mathematical models.We propose an image restoration algorithm for SXIsimulated observation images that can recover large-scale structure information on the magnetosphere.The idea is to train a patch estimator by selecting noise–clean patch pairs with the same distribution through the Classification–Expectation Maximization algorithm to achieve the restoration estimation of the SXI-simulated observation image,whose mapping relationship with the target image is established by the patch estimator.The Classification–Expectation Maximization algorithm is used to select multiple patch clusters with the same distribution and then train different patch estimators so as to improve the accuracy of the estimator.Experimental results showed that our image restoration algorithm is superior to other classical image restoration algorithms in the SXI-simulated observation image restoration task,according to the peak signal-to-noise ratio and structural similarity.The restoration results of SXI-simulated observation images are used in the tangent fitting approach and the computed tomography approach toward magnetospheric reconstruction techniques,significantly improving the reconstruction results.Hence,the proposed technology may be feasible for processing SXI-simulated observation images. 展开更多
关键词 Solar wind Magnetosphere Ionosphere Link Explorer(SMILE) soft x-ray imager MAGNETOPAUSE image restoration
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