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
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
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
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
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
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
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
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
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
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
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
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
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
基金supported by the U.S.National Science Foundation (2208972,2120559,and 2323117)
文摘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.
基金the National Natural Science Foundation of China (Grant nos.21233004,21303147 and 21473148,etc.)the National Key Research and Development Program (Grant no.2016YFB0901500)
文摘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.
基金Supported by Partially funded by FESR P.O.Apulia Region 2007-2013-Action 1.2.4,No.3Q5AX31
文摘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.
基金the Science Achievement Scholarship of Thailand(SAST)for financial supportpartially supported by the Institute of Nanomaterials Research and Innovation for Energy(IN-RIE)+1 种基金the Research and Graduate Studies,Khon Kaen University(KKU)Synchrotron Light Research Institute(SLRI),Thailand。
文摘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.
基金financialy supported by National Key R&D Program of China(2022YFB2402600)the National Natural Science Foundation of China(22279166)+1 种基金the Research Start-up Funds from Sun Yat-Sen University(200306)the Fundamental Research Funds for the Central Universities,Sun Yat-Sen University(22qntd0101 and 22dfx01)
文摘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.
基金the financial support from China Scholarship Council(202108080263)Financial support by the Federal Ministry of Education and Research(BMBF)under the project“He Na”(03XP0390C)+1 种基金the German Research Foundation(DFG)under the joint German-Russian DFG project“KIBSS”(448719339)are acknowledgedthe financial support from the Federal Ministry of Education and Research(BMBF)under the project“Ka Si Li”(03XP0254D)in the competence cluster“Excell Batt Mat”。
文摘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.
文摘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.
基金supported by the Strategic Priority Research Program on Space Science, Chinese Academy of Sciences (Grant Nos. XDA15320104, XDA15052200 and XDA15320300)the National Natural Science Foundation of China (Grant Nos. 11427803, 11820101002, U1731241 and U1631242)+1 种基金the ‘Thousand Young Talents Plan’the Jiangsu Innovative and Entrepreneurial Talents Program
文摘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.
基金supported by the Strategic Priority Research Program on Space Science, Chinese Academy of Sciences (Grant No. XDA15320104)the National Natural Science Foundation of China (Grant Nos. 11427803, 11622327, 11703079, 11803093 and 11820101002)
文摘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.
基金supported by the National High Technology Development Program of China (Grant No. 2009AA8046006)
文摘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.
基金supported by National Natural Science Foundation of China (Nos. 10375070, 10305012)
文摘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.
基金supported by the Science and Technology Development Fund of Macao (Grant Nos.068/2011/A,048/2012/A2,039/2013/A2,091/2013/A3 and 020/2014/A1)by the Key Research Program of the Chinese Academy of Sciences (Grant No.KGZD-EW603)
文摘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.
基金supported by Korea Research Institute of Standards and Science(KRISS–2019–GP2019-0014)。
文摘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.