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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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The application of synchrotron X-ray techniques to the study ofrechargeable batteries 被引量:4
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作者 Zhengliang Gong Yong Yang 《Journal of Energy Chemistry》 SCIE EI CAS CSCD 2018年第6期1566-1583,共18页
The increased use of rechargeable batteries in portable electronic devices and the continuous develop-ment of novel applications (e.g. transportation and large scale energy storage), have raised a strong de-mand for... The increased use of rechargeable batteries in portable electronic devices and the continuous develop-ment of novel applications (e.g. transportation and large scale energy storage), have raised a strong de-mand for high performance batteries with increased energy density, cycle and calendar life, safety andlower costs. This triggers significant efforts to reveal the fundamental mechanism determining batteryperformance with the use of advanced analytical techniques. However, the inherently complex character-istics of battery systems make the mechanism analysis sophisticated and difficult. Synchrotron radiationis an advanced collimated light source with high intensity and tunable energies. It has particular ad-vantages in electronic structure and geometric structure (both the short-range and long-range structure)analysis of materials on different length and time scales. In the past decades, synchrotron X-ray tech-niques have been widely used to understand the fundamental mechanism and guide the technologicaloptimization of batteries. In particular, in situ and operando techniques with high spatial and temporalresolution, enable the nondestructive, real time dynamic investigation of the electrochemical reaction,and lead to significant deep insights into the battery operation mechanism. This review gives a brief introduction of the application of synchrotron X-ray techniques to the inves-tigation of battery systems. The five widely implicated techniques, including X-ray diffraction (XRD), PairDistribution Function (PDF), Hard and Soft X-ray absorption spectroscopy (XAS) and X-ray photoelectronspectroscopy (XPS) will be reviewed, with the emphasis on their in situ studies of battery systems during cycling. 展开更多
关键词 Rechargeable battery Synchrotron x-ray techniques x-ray diffraction x-ray absorption spectroscopy Pair Distribution Function x-ray photoelectron spectroscopy
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Screening and early diagnosis of osteoporosis through X-ray and ultrasound based techniques 被引量:5
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作者 Paola Pisani Maria Daniela Renna +5 位作者 Francesco Conversano Ernesto Casciaro Maurizio Muratore Eugenio Quarta Marco Di Paola Sergio Casciaro 《World Journal of Radiology》 CAS 2013年第11期398-410,共13页
Effective prevention and management of osteoporosis would require suitable methods for population screenings and early diagnosis. Current clinicallyavailable diagnostic methods are mainly based on the use of either X-... Effective prevention and management of osteoporosis would require suitable methods for population screenings and early diagnosis. Current clinicallyavailable diagnostic methods are mainly based on the use of either X-rays or ultrasound(US). All X-ray based methods provide a measure of bone mineral density(BMD), but it has been demonstrated that other structural aspects of the bone are important in determining fracture risk, such as mechanical features and elastic properties, which cannot be assessed using densitometric techniques. Among the most commonly used techniques, dual X-ray absorptiometry(DXA) is considered the current 'gold standard' for osteoporosis diagnosis and fracture risk prediction. Unfortunately, as other X-ray based techniques, DXA has specific limitations(e.g., use of ionizing radiation, large size of the equipment, high costs, limited availability) that hinder its application for population screenings and primary care diagnosis. This has resulted in an increasing interest in developing reliable pre-screening tools for osteoporosis such as quantitative ultrasound(QUS) scanners, which do not involve ionizing radiation exposure and represent a cheaper solution exploiting portable and widely available devices. Furthermore, the usefulness of QUS techniques in fracture risk prediction has been proven and, with the last developments, they are also becoming a more and more reliable approach for assessing bone quality. However, the US assessment of osteoporosis is currently used only as a pre-screening tool, requiring a subsequent diagnosis confirmation by means of a DXA evaluation. Here we illustrate the state of art in the early diagnosis of this 'silent disease' and show up recent advances for its prevention and improved management through early diagnosis. 展开更多
关键词 Diagnosis of OSTEOPOROSIS SCREENING techniqueS x-ray BASED methods Quantitative ULTRASOUND Peripheral sites Bone mineral density
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Dynamic phase transition behavior of a LiMn_(0.5)Fe_(0.5)PO_(4) olivine cathode material for lithium-ion batteries revealed through in-situ X-ray techniques 被引量:5
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作者 Sujeera Pleuksachat Phongsit Krabao +6 位作者 Sarawut Pongha Viyada Harnchana Pawinee Klangtakai Wanwisa Limphirat Siriwat Soontaranon Jeffrey Nash Nonglak Meethong 《Journal of Energy Chemistry》 SCIE EI CAS CSCD 2022年第8期452-459,I0012,共9页
LiMn_(0.5)Fe_(0.5)PO_(4) has attracted great interest due to its good electrochemical performance and higher operating voltages.This has led to a greater than 30 percent higher energy density than for commercial Li Fe... LiMn_(0.5)Fe_(0.5)PO_(4) has attracted great interest due to its good electrochemical performance and higher operating voltages.This has led to a greater than 30 percent higher energy density than for commercial Li Fe PO4 olivine cathodes.Understanding the phase transition behaviors and kinetics of this material will help researchers to design and develop next generation cathodes for Li-ion batteries.In this study,we investigated non-equilibrium phase transition behaviors in a LiMn_(0.5)Fe_(0.5)PO_(4) cathode material during charge–discharge processes by varying current rates(C-rates)using synchrotron in-situ X-ray techniques.These methods included wide angle X-ray scattering(in-situ WAXS)and X-ray absorption spectroscopy(in-situ XAS).The WAXS spectra indicate that the phase transition of LiMn_(0.5)Fe_(0.5)PO_(4) material at slow C-rates is induced by a two-phase reaction.In contrast,at a high C-rate(5 C),the formation of an intermediate phase upon discharge is clearly observed.Concurrently,the oxidation numbers of the redox reactions of Fe^(2+)/Fe^(3+)and Mn^(2+)/Mn^(3+)were evaluated using in-situ XAS.This combination of synchrotron in-situ X-ray techniques gives clear insights into the non-equilibrium phase transition behavior of a LiMn_(0.5)Fe_(0.5)PO_(4) cathode material.This new understanding will be useful for further developments of this highly promising cathode material for practical commercialization. 展开更多
关键词 LiMn_(0.5)Fe_(0.5)PO_(4) Phase transition In-situ x-ray techniques
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Understanding Pseudocapacitance Mechanisms by Synchrotron X-ray Analytical Techniques 被引量:1
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作者 Pei Tang Wuyang Tan +7 位作者 Guangyang Deng Yunting Zhang Shan Xu Qijun Wang Guosheng Li Jian Zhu Qingyun Dou Xingbin Yan 《Energy & Environmental Materials》 SCIE EI CAS CSCD 2023年第4期312-331,共20页
Pseudocapacitive materials that store charges via reversible surface or near-surface faradaic reactions are capable of overcoming the capacity limitations of electrical double-layer capacitors.Revealing the structure... Pseudocapacitive materials that store charges via reversible surface or near-surface faradaic reactions are capable of overcoming the capacity limitations of electrical double-layer capacitors.Revealing the structure–activity relationship between the microstructural features of pseudocapacitive materials and their electrochemical performance on the atomic scale is the key to build high-performance capacitor-type devices containing ideal pseudocapacitance effect.Currently,the high brightness(flux),and spectral and coherent nature of synchrotron X-ray analytical techniques make it a powerful tool for probing the structure–property relationship of pseudocapacitive materials.Herein,we report a comprehensive and systematic review of four typical characterization techniques(synchrotron X-ray diffraction,pair distribution function[PDF]analysis,soft X-ray absorption spectroscopy,and hard X-ray absorption spectroscopy)for the study of pseudocapacitance mechanisms.In addition,we offered significant insights for understanding and identifying pseudocapacitance mechanisms(surface redox pseudocapacitance,intercalation pseudocapacitance,and the extrinsic pseudocapacitance phenomenon in battery materials)by combining in situ hard XAS and electrochemical analyses.Finally,a perspective for further depth of understanding into the pseudocapacitance mechanism using synchrotron X-ray analytical techniques is proposed. 展开更多
关键词 in situ experiments pseudocapacitive materials structure-property relationship synchrotron x-ray analytical techniques
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Ultrasmall CoS nanoparticles embedded in heteroatom-doped carbon for sodium-ion batteries and mechanism explorations via synchrotron X-ray techniques
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作者 Congcong Liu Qiongqiong Lu +8 位作者 Mikhail V.Gorbunov Ahmad Omar Ignacio G.Gonzalez Martinez Panpan Zhao Martin Hantusch Antonius Dimas Chandra Permana Huanyu He Nikolai Gaponik Daria Mikhailova 《Journal of Energy Chemistry》 SCIE EI CAS CSCD 2023年第4期373-381,共9页
Transition metal sulfides have been regarded as promising anode materials for sodium-ion batteries(SIB).However,they face the challenges of poor electronic conductivity and large volume change,which result in capacity... Transition metal sulfides have been regarded as promising anode materials for sodium-ion batteries(SIB).However,they face the challenges of poor electronic conductivity and large volume change,which result in capacity fade and low rate capability.In this work,a composite containing ultrasmall CoS(~7 nm)nanoparticles embedded in heteroatom(N,S,and O)-doped carbon was synthesized by an efficient one-step sulfidation process using a Co(Salen)precursor.The ultrasmall CoS nanoparticles are beneficial for mechanical stability and shortening Na-ions diffusion pathways.Furthermore,the N,S,and O-doped defect-rich carbon provides a robust and highly conductive framework enriched with active sites for sodium storage as well as mitigates volume expansion and polysulfide shuttle.As anode for SIB,CoS@HDC exhibits a high initial capacity of 906 mA h g^(-1)at 100 mA g^(-1)and a stable long-term cycling life with over 1000 cycles at 500 mA g^(-1),showing a reversible capacity of 330 mA h g^(-1).Meanwhile,the CoS@HDC anode is proven to maintain its structural integrity and compositional reversibility during cycling.Furthermore,Na-ion full batteries based on the CoS@HDC anode and Na_(3)V_(2)(PO_(4))_(3)cathode demonstrate a stable cycling behavior with a reversible specific capacity of~200 m A h g^(-1)at least for 100 cycles.Moreover,advanced synchrotron operando X-ray diffraction,ex-situ X-ray absorption spectroscopy,and comprehensive electrochemical tests reveal the structural transformation and the Co coordination chemistry evolution of the CoS@HDC during cycling,providing fundamental insights into the sodium storage mechanism. 展开更多
关键词 Sodium-ion batteries Cobalt sulfide nanoparticles Heteroatom-doped porous carbon matrix Synchrotron x-ray techniques Reaction mechanisms
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Water Quality Monitoring of the Bezerra River (Cascavel, Brazil) Using SR-TXRF Technique
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作者 Phallcha Luízar Obregón Fernando Rodolfo Espinoza-Quinones Aparecido Nivaldo Módenes 《Journal of Chemistry and Chemical Engineering》 2014年第6期587-595,共9页
The present study aims to monitor and assess the water quality of the Bezerra River located in the Western Brazilian Parana state. For the monitoring of river waters, six samplings were established per month during on... The present study aims to monitor and assess the water quality of the Bezerra River located in the Western Brazilian Parana state. For the monitoring of river waters, six samplings were established per month during one year. As indicators of the water quality, physico-chemical parameters such as water temperature, pH, turbidity, dissolved oxygen and COD (chemical oxygen demand) were chosen, as well as trace and majority element concentrations. It is noteworthy that the mean annual values of conductivity, turbidity and COD have progressively increased along the river with maximum values after the Cascavel western sewage treatment plant. Only 13 elements were found in the six collection points, but the metallic elements Cr, Mn, Fe, Cu and Zn have shown concentrations above the maximum limits recommended by Brazilian environmental legislation, suggesting the presence of highly polluting anthropogenic sources. Correlation analyses were used to determine the spatio-variability of water quality variables. The six collection sites were grouped into two clusters, with the element composition in the first cluster (sites 1, 2 and 6) being due to strong anthropogenic activities. The study of the Bezerra River water quality could help to develop municipal environmental policies and help with the management of water conservation in the Bezerra River basin. 展开更多
关键词 River water pollution physico-chemical parameters SR-TXRF (synchrotron radiation total reflection x-ray fluorescence) technique element concentrations statistical analysis.
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Simulations and software development for the Hard X-ray Imager onboard ASO-S 被引量:7
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作者 Yang Su Wei Liu +13 位作者 You-Ping Li Zhe Zhang Gordon JHurford Wei Chen Yu Huang Zhen-Tong Li Xian-Kai Jiang Hao-Xiang Wang Fan-Xiao-Yu Xia Chang-Xue Chen Wen-Hui Yu Fu Yu Jian Wu Wei-Qun Gan 《Research in Astronomy and Astrophysics》 SCIE CAS CSCD 2019年第11期93-102,共10页
China’s first solar mission,the Advanced Space-based Solar Observatory(ASO-S),is now changing from Phase B to Phase C.Its main scientific objectives are summarized as’1M2B’,namely magnetic field and two types of bu... China’s first solar mission,the Advanced Space-based Solar Observatory(ASO-S),is now changing from Phase B to Phase C.Its main scientific objectives are summarized as’1M2B’,namely magnetic field and two types of bursts(solar flares and coronal mass ejections).Among the three scientific payloads,Hard X-ray Imager(HXI)observes images and spectra of X-ray bursts in solar flares.In this paper,we briefly report on the progresses made by the HXI science team(data and software team)during the design phase(till May 2019).These include simulations of HXI imaging,optimization of HXI grids,development of imaging algorithms,estimation of orbital background,as well as in-orbit calibration plan.These efforts provided guidance for the engineering,improved HXI’s imaging capability and reduced the cost of the instrument. 展开更多
关键词 techniqueS x-ray imaging-techniques simulation SUN x-rays-Sun FLARES
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Hard X-ray Imager (HXI) onboard the ASO-S mission 被引量:9
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作者 Zhe Zhang Deng-Yi Chen +29 位作者 Jian Wu Jin Chang Yi-Ming Hu Yang Su Yan Zhang Jian-Ping Wang Yao-Ming Liang Tao Ma Jian-Hua Guo Ming-Sheng Cai Yong-Qiang Zhang Yong-Yi Huang Xiao-Yan Peng Zong-Bin Tang Xuan Zhao Hong-He Zhou Lian-Guo Wang Jing-Xing Song Miao Ma Guang-Zhou Xu Jian-Feng Yang Di Lu Ying-Hong He Jin-You Tao Xiao-Long Ma Bao-Gang Lv Yan-Ping Bai Cai-Xia Cao Yu Huang Wei-Qun Gan 《Research in Astronomy and Astrophysics》 SCIE CAS CSCD 2019年第11期49-62,共14页
Hard X-ray Imager(HXI)is one of the three scientific instruments onboard the Advanced Spacebased Solar Observatory(ASO-S)mission,which is proposed for the 25th solar maximum by the Chinese solar community.HXI is desig... Hard X-ray Imager(HXI)is one of the three scientific instruments onboard the Advanced Spacebased Solar Observatory(ASO-S)mission,which is proposed for the 25th solar maximum by the Chinese solar community.HXI is designed to investigate the non-thermal high-energy electrons accelerated in solar flares by providing images of solar flaring regions in the energy range from 30 keV to 200 keV.The imaging principle of HXI is based on spatially modulated Fourier synthesis and utilizes about 91 sets of bi-grid sub-collimators and corresponding LaBr3 detectors to obtain Fourier components with a spatial resolution of about 3 arcsec and a time resolution better than 0.5 s.An engineering prototype has been developed and tested to verify the feasibility of design.In this paper,we present background,instrument design and the development and test status of the prototype. 展开更多
关键词 instrumentation:detectors space vehicles:instruments Sun:x-ray techniques:imaging spectroscopy
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Laser-produced plasma helium-like titanium Kα x-ray source and its application to Rayleigh-Taylor instability study 被引量:1
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作者 王瑞荣 陈伟民 +2 位作者 王伟 董佳钦 肖沙里 《Chinese Physics B》 SCIE EI CAS CSCD 2010年第7期362-368,共7页
Several experiments are performed on the ShenGuang-Ⅱ laser facility to investigate an x-ray source and test radiography concepts. X-ray lines emitted from laser-produced plasmas are the most practical means of genera... Several experiments are performed on the ShenGuang-Ⅱ laser facility to investigate an x-ray source and test radiography concepts. X-ray lines emitted from laser-produced plasmas are the most practical means of generating these high intensity sources. By using a time-integrated space-resolved keV spectroscope and pinhole camera, potential helium-like titanium Kα x-ray backlighting (radiography) line source is studied as a function of laser wavelength, ratio of pre-pulse intensity to main pulse intensity, and laser intensity (from 7.25 to ~ 11.3 × 10^15 W/cm2). One-dimensional radiography using a grid consisting of 5 #m Au wires on 16 μm period and the pinhole-assisted point projection is tested. The measurements show that the size of the helium-like titanium Ka source from a simple foil target is larger than 100 ~m, and relative x-ray line emission conversion efficiency ~x from the incident laser light energy to helium- like titanium K-shell spectrum increases significantly with pre-pulse intensity increasing, increases rapidly with laser wavelength decreasing, and increases moderately with main laser intensity increasing. It is also found that a gold gird foils can reach an imaging resolution better than 5-μm featured with high contrast. It is further demonstrated that the pinhole-assisted point projection at such a level will be a novel two-dimensional imaging diagnostic technique for inertial confinement fusion experiments. 展开更多
关键词 x-ray source plasma diagnostic techniques x-ray spectra
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Tobacco Sorter和Tobacco Scan 6000烟草异物剔除系统的比较 被引量:11
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作者 唐向阳 张勇 +3 位作者 黄岗 谢红万 关宏 李江有 《烟草科技》 EI CAS 2004年第2期13-16,共4页
对TobaccoSorter和TobaccoScan 60 0 0系列的烟草异物剔除系统进行了对比 ,从系统组成、烟叶单层化及稳定传送装置、图像获取方式及识别算法、异物的剔除方法、照明光源等方面进行了详细的比较和分析 ,由此看出 :随着相关技术的快速发... 对TobaccoSorter和TobaccoScan 60 0 0系列的烟草异物剔除系统进行了对比 ,从系统组成、烟叶单层化及稳定传送装置、图像获取方式及识别算法、异物的剔除方法、照明光源等方面进行了详细的比较和分析 ,由此看出 :随着相关技术的快速发展 ,应用线性CCD摄像机作为检测装置的异物剔除系统将具有越来越明显的优势。 展开更多
关键词 TOBACCO sorter TOBACCO Scan6000系列 烟草异物剔除系统 计算机视觉技术 数字图像处理
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The Electron Temperature Estimation Using Soft X-Ray Imaging in HT-7 Tokamak
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作者 甄香君 胡立群 +5 位作者 万宝年 陈忠勇 石跃江 林士耀 丁永华 周立武 《Plasma Science and Technology》 SCIE EI CAS CSCD 2006年第2期147-150,共4页
In order to estimate the electron temperature soft x-ray imaging diagnostics using a double filter technique has been developed in the HT-7 tokamak. The chosen thicknesses of the Be foil are 12.5 μm and 70 μm, respe... In order to estimate the electron temperature soft x-ray imaging diagnostics using a double filter technique has been developed in the HT-7 tokamak. The chosen thicknesses of the Be foil are 12.5 μm and 70 μm, respectively. In this article both the main design of the diagnostic configuration and the method to estimate the electron temperature are presented. The results agree with those estimated from the soft x-ray pulse height analyzer (PHA). The main causes of systematic error have also been investigated. 展开更多
关键词 different foils technique soft x-ray electron temperature tokamak plasma
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Global Mg/Si and Al/Si Distributions on the Lunar Surface Derived from Chang'E-2 X-ray Spectrometer
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作者 Wu-Dong Dong Xiao-Ping Zhang +2 位作者 Meng-Hua Zhu Ao-Ao Xu Ze-Sheng Tang 《Research in Astronomy and Astrophysics》 SCIE CAS CSCD 2016年第1期31-38,共8页
The technique of X-ray fluorescence remote sensing plays a significant role in research related to the chemical compositions of the Moon. Here we describe the data analysis method for China's Chang'E-2 X-ray spectro... The technique of X-ray fluorescence remote sensing plays a significant role in research related to the chemical compositions of the Moon. Here we describe the data analysis method for China's Chang'E-2 X-ray spectrometer in detail and present the preliminary results about the first global Mg/Si and Al/Si maps of the lunar surface. Our results show that the distributions of Mg/Si and Al/Si correlate well with terrains on the Moon. The higher Mg/Si ratio corresponds to the mare regions while the lower value corresponds to the highland terrains. The map of the Al/Si ratio shows a reversed distribution compared with the map of the Mg/Si ratio. 展开更多
关键词 Moon -- planets and satellites: composition -- techniques: spectroscopic -- x-rays: general
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黑灯下料车间设计及分析
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作者 巫江 方异锋 +5 位作者 王佳 方羽 赵一君 王辉甫 杨勇 周瑜忻 《机电工程技术》 2024年第9期205-209,共5页
随着工业和信息化部智能制造试点示范工厂的推进和国家智能制造的发展需要,我国各大重型机械装备企业正在建设一系列灯塔工厂以及黑灯工厂。黑灯下料车间作为集中备料中心以满足各种规格零件下料以及提高钢板材料性能的需求日益紧迫。... 随着工业和信息化部智能制造试点示范工厂的推进和国家智能制造的发展需要,我国各大重型机械装备企业正在建设一系列灯塔工厂以及黑灯工厂。黑灯下料车间作为集中备料中心以满足各种规格零件下料以及提高钢板材料性能的需求日益紧迫。通过对黑灯下料车间的工艺梳理,分析应用到的关键技术,从设计及实施角度对黑灯车间的建设提出优化建议。通过程控行车、格栅托盘、辊道输送和切割机组有机结合,组成机群式下料中心,实现了从钢板上料,输送以及切割的无人化。切割完成后的钢板依次通过六轴机器人组成的小件分拣和码垛单元、桁架机械手组成的大件分拣和码垛单元,有序地将切割后的零件进行分拣及配盘。通过多角度的经济对比分析以及项目验证,黑灯下料车间作为下料领域的专业高效管理平台,结合自动化设备及信息技术建成的智能车间,具有重要的价值和应用前景。 展开更多
关键词 黑灯车间 机群式下料 智能分拣 先进技术
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Characterization of lattice parameters gradient of Cu(In1-xGax)Se2 absorbing layer in thin-film solar cell by glancing incidence X-ray diffraction technique
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作者 Yong-Il Kim Ki-Bok Kim Miso Kim 《Journal of Materials Science & Technology》 SCIE EI CAS CSCD 2020年第16期193-201,共9页
In or Ga gradients in the Cu(In1-xGax)Se2(CIGS)absorbing layer lead to change the lattice parameters of the absorbing layer,giving rise to the bandgap grading in the absorbing layer which is directly associated with t... In or Ga gradients in the Cu(In1-xGax)Se2(CIGS)absorbing layer lead to change the lattice parameters of the absorbing layer,giving rise to the bandgap grading in the absorbing layer which is directly associated with the degree of absorbing ability of the CIGS solar cell.We tried to characterize the depth profile of the lattice parameters of the CIGS absorbing layer using a glancing incidence X-ray diffraction(GIXRD)technique,and then investigate the bandgap grading of the CIGS absorbing layer.When the glancing incident angle increased from 0.50 to 5.00°,the a and c lattice parameters of the CIGS absorbing layer gradually decreased from 5.7776(3)to 5.6905(2)?,and 11.3917(3)to 11.2114(2)?,respectively.The depth profile of the lattice parameters as a function of the incident angle was consistent with vertical variation in the compositionof In or Ga with depth in the absorbing layer.The variation of the lattice parameters was due to the difference between the ionic radius of In and Ga co-occupying at the same crystallographic site.According to the results of the depth profile of the refined parameters using GIXRD data,the bandgap of the CIGS absorber layer was graded over a range of 1.222-1.532 eV.This approach allows to determine the In or Ga gradients in the CIGS absorbing layer,and to nondestructively guess the bandgap depth profile through the refinement of the lattice parameters using GIXRD data on the assumption that the changes of the lattice parameters or unit-cell volume follow a good approximation to Vegard’s law. 展开更多
关键词 Cu(In1-xGax)Se2 absorbing layer Depth profile Glancing incidence x-ray diffraction technique Bandgap grading Vegard’s law
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基于故障集分类的电力系统可靠性评估方法 被引量:26
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作者 黄江宁 郭瑞鹏 +2 位作者 赵舫 余秀月 杨桂钟 《中国电机工程学报》 EI CSCD 北大核心 2013年第16期112-121,11,共10页
针对现有电力系统可靠性评估方法计算效率低下的问题,提出了故障集分类的思想,以实现对系统状态的高效评估。该算法将系统故障状态分至排序故障集和抽样故障集择优处理,避免了抽样效率退化现象,同时对各重故障的抽样次数进行最优分配,... 针对现有电力系统可靠性评估方法计算效率低下的问题,提出了故障集分类的思想,以实现对系统状态的高效评估。该算法将系统故障状态分至排序故障集和抽样故障集择优处理,避免了抽样效率退化现象,同时对各重故障的抽样次数进行最优分配,有效地降低了抽样方差,加速收敛。应用该算法对IEEE-RTS79系统及修改后的高可靠性系统进行测试,结果表明,该方法与原始蒙特卡罗法和重要抽样方法相比,能够明显提高计算效率,对大型电力系统的可靠性评估具有实用价值。 展开更多
关键词 可靠性评估 蒙特卡罗抽样 故障集分类 快速排序法 均匀抽样
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具有创造成就的科学家关于创造的概念结构 被引量:31
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作者 张景焕 金盛华 《心理学报》 CSSCI CSCD 北大核心 2007年第1期135-145,共11页
运用Q分类及多尺度分析方法,研究具有创造成就的科学家关于创造成就的概念结构。被试是30名来自物理、化学、数学、地学和生命科学领域的具有创造成就的科学家。研究发现,具有创造成就的科学家关于创造成就的概念结构由“成就取向/内心... 运用Q分类及多尺度分析方法,研究具有创造成就的科学家关于创造成就的概念结构。被试是30名来自物理、化学、数学、地学和生命科学领域的具有创造成就的科学家。研究发现,具有创造成就的科学家关于创造成就的概念结构由“成就取向/内心体验取向”、“主动进取/踏实肯干”两个维度构成;取得科学创造成就的重要特征是“成就取向”和“主动进取”。作者进一步讨论了主动进取对于取得创造性成就的意义。 展开更多
关键词 具有创造成就的科学家 概念结构 Q分类 多尺度分析
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微细粒嵌布难选鲕状赤铁矿现状研究及展望 被引量:5
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作者 刘淑贤 申丽丽 牛福生 《中国矿业》 北大核心 2012年第1期70-71,77,共3页
鲕状赤铁矿因其微细粒嵌布、结构复杂等特点,一直被认为是世界选矿难题。本文主要研究了其在我国的利用现状,以及强磁选-反浮选、絮凝-强磁选、磁化焙烧-磁选等传统基础选别技术,并讨论了一种高效选别技术——深度还原,对鲕状赤铁矿的... 鲕状赤铁矿因其微细粒嵌布、结构复杂等特点,一直被认为是世界选矿难题。本文主要研究了其在我国的利用现状,以及强磁选-反浮选、絮凝-强磁选、磁化焙烧-磁选等传统基础选别技术,并讨论了一种高效选别技术——深度还原,对鲕状赤铁矿的选别具有很重要的现实意义。 展开更多
关键词 鲕状赤铁矿 选别技术 深度还原
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计及多状态元件模型的系统状态快速排序技术 被引量:25
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作者 刘海涛 孙元章 +1 位作者 程林 王鹏 《电力系统自动化》 EI CSCD 北大核心 2008年第1期16-21,共6页
在实际电力系统中,由于元件的停运概率不同,一些高重故障会比低重故障的发生概率大。这些大概率高重故障状态的数量多,且对系统可靠性的影响大。而在可靠性评估中,状态枚举法通常采用截止故障重数进行状态筛选,会忽略掉这些大概率高重... 在实际电力系统中,由于元件的停运概率不同,一些高重故障会比低重故障的发生概率大。这些大概率高重故障状态的数量多,且对系统可靠性的影响大。而在可靠性评估中,状态枚举法通常采用截止故障重数进行状态筛选,会忽略掉这些大概率高重故障事件。文中提出计及多状态元件模型的快速排序技术,基于元件异常状态序列与相邻系统状态,能够按照概率从大到小依次选取系统状态,直至满足评估精度或数量要求。与直接选择法相比,计算效率优势十分明显。由于该方法能够选出大概率高重故障状态,因此,与截止故障重数方法相比,该方法只需少量的系统状态就可获得较高的评估精度。最后以IEEE-RTS为算例验证了该结论。 展开更多
关键词 电力系统可靠性 系统状态选择 快速排序技术 多状态元件模型 概率系数 相邻系统 状态
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运行可靠性在线短期评估方案 被引量:38
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作者 孙元章 刘海涛 +1 位作者 程林 王鹏 《电力系统自动化》 EI CSCD 北大核心 2008年第3期4-8,共5页
运行可靠性短期评估基于能量管理系统/广域测量系统(EMS/WAMS),研究电力系统在实时运行状态下的短期可靠性水平。建立了一套运行可靠性在线短期评估方案,给出了指标体系、评估算法和应用框架。进一步介绍了方案实施中所采用的关键技术:... 运行可靠性短期评估基于能量管理系统/广域测量系统(EMS/WAMS),研究电力系统在实时运行状态下的短期可靠性水平。建立了一套运行可靠性在线短期评估方案,给出了指标体系、评估算法和应用框架。进一步介绍了方案实施中所采用的关键技术:通过建立元件实时模型,评估系统在当前运行状态下的可靠性;基于瞬时状态概率评估系统的短期可靠性;采用快速排序技术进行系统状态选择,协调评估精度和速度的矛盾,实现在线评估;基于系统实时运行工况分析系统状态在预测时刻的后果。通过IEEE-RTS系统验证了整套方案的可行性和有效性。 展开更多
关键词 短期运行可靠性 在线评估方案 指标体系 元件实时模型 瞬时概率 快速排序技术
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