This study presents an electronics system for cosmic X-ray polarization detection(CXPD).The CXPD was designed as a high-sensitivity soft X-ray polarimeter with a measurement energy range of 2-10 keV carried by a CubeS...This study presents an electronics system for cosmic X-ray polarization detection(CXPD).The CXPD was designed as a high-sensitivity soft X-ray polarimeter with a measurement energy range of 2-10 keV carried by a CubeSat.A stable and functionally complete electronics system under power and space constraints is a key challenge.The complete CXPD electronics system(CXPDES)comprises hardware and firmware.CXPDES adopts a three-layer electronic board structure based on functionality and available space.Two gas pixel detectors(GPDs)were placed on the top layer board,and CXPDES provided the GPDs with voltages up to-4000 V.Each GPD signal was digitized,compressed,encoded,and stored before being transmitted to the ground.The CXPDES provided stable and high-speed communication based on a scheme that separated command and data transmission,and it supports the CXPDES in-orbit upgrade.In addition,environmental monitors,silicon photomultiplier(SiPM)triggers,power management,GPDs configuration,and mode switches were included in the overall operating logic of the CXPDES.The results obtained by testing the CXPDES showed that it satisfied all the requirements of CXPD.The CXPDES provides design experience and technological readiness for future large-area X-ray polarimetry missions.展开更多
OBJECTIVE: To observe the distribution of copper in the subcellular structure for the understanding of primary pathogenesis of hepatolenticular degeneration (HLD). METHODS: Skin fibroblasts taken from HLD patients wer...OBJECTIVE: To observe the distribution of copper in the subcellular structure for the understanding of primary pathogenesis of hepatolenticular degeneration (HLD). METHODS: Skin fibroblasts taken from HLD patients were cultured as an in vitro model of HLD, and the control cells taken from healthy volunteers were clutured in the same way. The distribution of copper inside and outside of lysosomes in fibroblasts was detected by quantitative electron probe X-ray microanalysis. The relationship between the subcellular location of copper and the genotype of the patients, and relationship between the distribution of copper and the course of the disease were analyzed. RESULTS: The content of Cu^(2+) inside lysosomes of HLD cells (14.6±2.1 mmol/kg) and of heterozygote cells (11.6±0.6 mmol/kg) was higher than that of normal cells (4.5±1.2 mmol/kg) (P<0.01). The content of Cu^(2+) outside lysosomes of HLD cells (17.5±4.2 mmol/kg) and of heterozygote cells (12.0±0.9 mmol/kg) was higher than that of normal cells (4.7±1.2 mmol/kg) (P<0.01). The distribution of copper in the subcellular structure was correlated with disease courses of HLD patients. With the progression of the disease, more copper was deposited in lysosomes (r=0.85, P<0.01). The content of copper in the diffused cytoplasmic compartment in HLD cells was correlated with that of sulfur (r=0.86, P<0.05), but not in heterozygote and normal cells. CONCLUSIONS: In the early stage of HLD, copper is accumulated outside lysosome, which is paralleled with increase of metallothionein-like proteins (copper and sulfur-binding proteins). With the development of the disease, more copper is deposited inside lysosome than outside lysosome. We conclude that the up-regulation expression of copper and sulfur-binding proteins and copper accumulation in lysosomes may play an important role in lowering the ATP7B gene mutation-induced toxic effects of free copper on the cell.展开更多
Distributed X-ray sources comprise a single vacuum chamber containing multiple X-ray sources that are triggered and emit X-rays at a specific time and location. This process facilitates an application for innovative s...Distributed X-ray sources comprise a single vacuum chamber containing multiple X-ray sources that are triggered and emit X-rays at a specific time and location. This process facilitates an application for innovative system concepts in X-ray and computer tomography. This paper proposes a novel electron beam focusing, shaping,and deflection electron gun for distributed X-ray sources.The electron gun uses a dispenser cathode as an electron emitter, a mesh grid to control emission current, and two electrostatic lenses for beam shaping, focusing, and deflection. Novel focusing and deflecting electrodes were designed to increase the number of focal spots in the distributed source. Two identical half-rectangle opening electrodes are controlled by adjusting the potential of the two electrodes to control the electron beam trajectory, and then, multifocal spots are obtained on the anode target. The electron gun can increase the spatial density of the distributed X-ray sources, thereby improving the image quality. The beam experimental results show that the focal spot sizes of the deflected(deflected amplitude 10.5 mm)and non-deflected electron beams at full width at half maximum are 0.80 mm 90.50 mm and 0.55 mm 90.40 mm, respectively(anode voltage 160 kV; beam current 30 mA). The imaging experimental results demonstrate the excellent spatial resolution and time resolution of an imaging system built with the sources, which has an excellent imaging effect on a field-programmable gate array chip and a rotating metal disk.展开更多
The readout electronics for a prototype soft X-ray spectrometer based on silicon drift detector(SDD),for precisely measuring the energy and arrival time of X-ray photons is presented in this paper.The system mainly co...The readout electronics for a prototype soft X-ray spectrometer based on silicon drift detector(SDD),for precisely measuring the energy and arrival time of X-ray photons is presented in this paper.The system mainly consists of two parts,i.e.,an analog electronics section(including a pre-amplifier,a signal shaper and filter,a constant fraction timing circuit,and a peak hold circuit)and a digital electronics section(including an ADC and a TDC).Test results with X-ray sources show that an energy dynamic range of 1-10 keV with an integral nonlinearity of less than 0.1%can be achieved,and the energy resolution is better than 160 eV @ 5.9 keV FWHM.Using a waveform generator,test results also indicate that time resolution of the electronics system is about 3.7 ns,which is much less than the transit time spread of SDD(<100 ns)and satisfies the requirements of future applications.展开更多
An ultra-high vacuum (UHV) compatible electron spectrometer employing a double toroidal analyzer has been de- veloped. It is designed to be combined with a custom-made scanning tunneling microscope (STM) to study ...An ultra-high vacuum (UHV) compatible electron spectrometer employing a double toroidal analyzer has been de- veloped. It is designed to be combined with a custom-made scanning tunneling microscope (STM) to study the spatially localized electron energy spectrum on a surface. A tip-sample system composed of a piezo-driven field-emission tungsten tip and a sample of highly ordered pyrolytic graphite (HOPG) is employed to test the performance of the spectrometer. Two-dimensional images of the energy-resolved and angle-dispersed electrons backscattered from the surface of HOPG are obtained, the performance is optimized and the spectrometer is calibrated. A complete electron energy loss spectrum covering the elastic peak to the secondary electron peaks for the HOPG surface, acquired at a tip voltage of -140 V and a sample current of 0.5 pA, is presented, demonstrating the viability of the spectrometer.展开更多
The Shanghai soft X-ray free-electron laser(SXFEL)user facility project started in 2016 and is expected to be open to users by 2022.It aims to deliver ultra-intense coherent femtosecond X-ray pulses to five endstation...The Shanghai soft X-ray free-electron laser(SXFEL)user facility project started in 2016 and is expected to be open to users by 2022.It aims to deliver ultra-intense coherent femtosecond X-ray pulses to five endstations covering a range of 100–620 eV for ultrafast X-ray science.Two undulator lines are designed and constructed,based on different lasing modes:self-amplified spontaneous emission and echo-enabled harmonic generation.The coherent scattering and imaging(CSI)endstation is the first of five endstations to be commissioned online.It focuses on high-resolution single-shot imaging and the study of ultrafast dynamic processes using coherent forward scattering techniques.Both the single-shot holograms and coherent diffraction patterns were recorded and reconstructed for nanoscale imaging,indicating the excellent coherence and high peak power of the SXFEL and the possibility of‘‘diffraction before destruction’’experiments at the CSI endstation.In this study,we report the first commissioning results of the CSI endstation.展开更多
Understanding electronic structure is crucial to enhance the battery performance. Soft X-ray spectroscopy(SXS) is one of the most effective methods to provide direct probe of electronic states. Here, spectroscopic mea...Understanding electronic structure is crucial to enhance the battery performance. Soft X-ray spectroscopy(SXS) is one of the most effective methods to provide direct probe of electronic states. Here, spectroscopic measurements of transition metal 3 d and oxygen 2 p states are simply reviewed. Then, we mainly focus on the perspective of the development direction of modern SXS techniques. Although the true power of recently developed high efficiency mapping of resonant inelastic X-ray scattering(m RIXS) has been apparent for materials and chemistry studies, great challenges remain for mRIXS spectroscopic interpretation, and the understanding of the battery materials on novel redox activities remains elusive.展开更多
The bauxite mineral obtained from Araku, Vishakapatnam district of Andhra Pradesh, India is used in the present work. Structural characterization was performed by X-ray diffraction (XRD). The mineral was found to be g...The bauxite mineral obtained from Araku, Vishakapatnam district of Andhra Pradesh, India is used in the present work. Structural characterization was performed by X-ray diffraction (XRD). The mineral was found to be gibbsite in phase. The transitional metal ions present were investigated using electron paramagnetic resonance (EPR) and optical absorption spectra. The EPR results suggest that Fe3+ has replaced Al3+ in the unit cell of bauxite. The optical absorption spectrum is due to Fe3+ which indicates that it is in distorted octahedral environment. The near-infrared (NIR) spectrum is due to water fundamentals and combination overtones, which confirm the formula of the compound. The impurities in the mineral are identified using spectroscopic techniques.展开更多
Detection of sulfur-oxidizing bacteria has largely been dependent on targeted gene sequencing technology or traditional cell cultivation, which usually takes from days to months to carry out. This clearly does not mee...Detection of sulfur-oxidizing bacteria has largely been dependent on targeted gene sequencing technology or traditional cell cultivation, which usually takes from days to months to carry out. This clearly does not meet the requirements of analysis for time-sensitive samples and/or complicated environmental samples. Since energy-dispersive X-ray spectrometry(EDS) can be used to simultaneously detect multiple elements in a sample, including sulfur, with minimal sample treatment, this technology was applied to detect sulfur-oxidizing bacteria using their high sulfur content within the cell. This article describes the application of scanning electron microscopy imaging coupled with EDS mapping for quick detection of sulfur oxidizers in contaminated environmental water samples, with minimal sample handling. Scanning electron microscopy imaging revealed the existence of dense granules within the bacterial cells, while EDS identified large amounts of sulfur within them. EDS mapping localized the sulfur to these granules. Subsequent 16S rRNA gene sequencing showed that the bacteria detected in our samples belonged to the genus Chromatium, which are sulfur oxidizers. Thus, EDS mapping made it possible to identify sulfur oxidizers in environmental samples based on localized sulfur within their cells, within a short time(within 24 h of sampling). This technique has wide ranging applications for detection of sulfur bacteria in environmental water samples.展开更多
AIM To develop methods of articular cartilage preparation for X-ray-electron probe microanalysis and to study its elements content in experimental osteoarthrosis.METHODS Twenty dogs aged 2-8 years were divided in rese...AIM To develop methods of articular cartilage preparation for X-ray-electron probe microanalysis and to study its elements content in experimental osteoarthrosis.METHODS Twenty dogs aged 2-8 years were divided in research(aged 2 years, induction of osteoarthrosis-IOA) and intact group. Intact group included three subgroups(aged 2, 5 and 8 years). Samples of cartilage after araldite saturation and pouring were partially cut into semithin sections stained with methylene blue and with methylene blue-basic fuchsin. Their smooth surfaces were investigated by X-ray-electron probe microanalysis. Spatial distribution of sulfur, calcium and phosphorus and their concentrations(weight %) were investigated.RESULTS X-ray electron probe microanalysis revealed non-uniformsulfur distribution in cartilage of intact animals: Its content increases from superficial zone to deep one, this regularity was preserved in animals with IOA. Differences of IOA with spontaneous chondropathy were revealed. Spontaneous aging was characterized by calcium and phosphorus storage in deep and calcified zones and compensatory increase of sulfated glycosaminoglycans in intermediate and deep cartilage zones as evidenced by the metachromatic reaction and microanalysis data. Unlike spontaneous chondropathy connected with aging in experimentally stimulated osteoarthrosis more intensive storage of calcium but minor phosphorus in intermediate zone were marked. In IOA the calcified cartilage thinning and osteoclastic resorption are apparent with few changes of elements composition; the only difference from control is minority phosphorus content.CONCLUSION The obtained results demonstrate specific tricks of X-ray electron probe microanalysis and its possibility in the research of mechanisms of articular cartilage alterations in osteoarthrosis.展开更多
We measured electron temperatures through a hollow cathode-type discharge tube using several different floating probe methods. This method detected a shift in the floating potential when an AC voltage was applied to a...We measured electron temperatures through a hollow cathode-type discharge tube using several different floating probe methods. This method detected a shift in the floating potential when an AC voltage was applied to a probe through an intermediary blocking capacitor. The shift in the floating potential is described as a function of the electron temperature and the applied AC voltage. In this study, the effects of the frequency and waveform on the electron temperatures were systematically investigated. The electron temperature measured when using the floating probe method with applied sinusoidal and triangular voltages was lower than that measured with an applied rectangular voltage.The value in the high frequency range was close to that of the tail electron temperature.展开更多
This study presents a novel floating probe method to measure electron temperatures using a hollow cathode-type discharge tube. The proposed method detects a shift in the floating potential when an AC voltage is applie...This study presents a novel floating probe method to measure electron temperatures using a hollow cathode-type discharge tube. The proposed method detects a shift in the floating potential when an AC voltage is applied to a probe through an intermediary blocking capacitor. The shift in the floating potential is described as a function of the electron temperature and the applied AC voltage. The floating probe method is simpler than the Langmuir probe method because it does not require the measurement of volt-ampere characteristics. As the input AC voltage increases, the electron temperature converges. The electron temperature measured using the floating probe method with an applied sinusoidal voltage shows a value close to the first (tail) electron temperature in the range of the floating potential.展开更多
The formidable challenge of developing high-performance battery system stems from the complication of battery operations, both mechanically and electronically. In the electrodes and at the electrode-electrolyte interf...The formidable challenge of developing high-performance battery system stems from the complication of battery operations, both mechanically and electronically. In the electrodes and at the electrode-electrolyte interfaces, chemical reactions take place with evolving electron states. In addition to the extensive studies of material synthesis, electrochem- ical, structural, and mechanical properties, soft x-ray spectroscopy provides unique opportunities for revealing the critical electron states in batteries. This review discusses some of the recent soft x-ray spectroscopic results on battery binder, transition-metal based positive electrodes, and the solid-electrolyte-interphase. By virtue of soft x-ray's sensitivity to electron states, the electronic property, the redox during electrochemical operations, and the chemical species of the interphases could be fingerprinted by soft x-ray spectroscopy. Understanding and innovating battery technologies need a multimodal approach, and soft x-ray spectroscopy is one of the incisive tools to probe the chemical and physical evolutions in batteries.展开更多
Abstract Linear Thomson scattering of a short pulse laser by relativistic electron has been investigated using computer simulations. It is shown that scattering of an intense laser pulse of -33 fs full width at half m...Abstract Linear Thomson scattering of a short pulse laser by relativistic electron has been investigated using computer simulations. It is shown that scattering of an intense laser pulse of -33 fs full width at half maximum, with an electron of γ0 = 10 initial energy, generates an ultrashort, pulsed radiation of 76 attoseconds with a photon wavelength of 2.5 nm in the backward direction. The scattered radiation generated by a highly relativistic electron has superior quality in terms of its pulse width and angular distribution in comparison to the one generated by lower relativistic energy electron.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 influence of electron thermal conductivity on the laser x-ray conversion in the coupling of 3w. laser with Au plane target has been investigated by using a non-LTE radiation hydrodynamic code. The non-local electr...The influence of electron thermal conductivity on the laser x-ray conversion in the coupling of 3w. laser with Au plane target has been investigated by using a non-LTE radiation hydrodynamic code. The non-local electron thermal conductivity is introduced and compared with the other two kinds of the flux-limited Spitzer-Harm description. The results show that the non-local thermal conductivity causes the increase of the laser x-ray conversion efficiency and important changes of the plasma state and coupling feature.展开更多
Two soft X-ray pulse height analysis (PHA) systems, based on silicon drift detec- tor (SDD), were established on the experimental advanced superconducting tokamak (EAST) to measure spectrum of soft X-ray emissio...Two soft X-ray pulse height analysis (PHA) systems, based on silicon drift detec- tor (SDD), were established on the experimental advanced superconducting tokamak (EAST) to measure spectrum of soft X-ray emission. In this paper, the soft X-ray PHA systems on EAST are introduced and some experimental results of electron temperature in EAST obtained from the soft X-ray PHA diagnostic are presented.展开更多
The experimental data of Mαβ X-ray production cross sections for Pb and Bi by 9–40 keV electron impact have been given. Thin films with thick carbon substrates are used in the experiment. The effects of target stru...The experimental data of Mαβ X-ray production cross sections for Pb and Bi by 9–40 keV electron impact have been given. Thin films with thick carbon substrates are used in the experiment. The effects of target structure on the Mαβ X-ray production cross sections are corrected by using the Monte Carlo method. The corrected experimental data are compared with calculated cross sections in terms of the distorted-wave Born approximation(DWBA) theory. The measured Mαβ X-ray production cross sections for Pb and Bi are lower than the DWBA calculations. The atomic relaxation parameters used in comparing the DWBA values with experimental results affect the degree of difference.展开更多
In view of X-ray Free Electron Laser (XFEL) intensity prospects, we reviewed the past and recent work in view of amplification of powerful XFEL laser pulse to achieve intensity in the regime of high field science. We ...In view of X-ray Free Electron Laser (XFEL) intensity prospects, we reviewed the past and recent work in view of amplification of powerful XFEL laser pulse to achieve intensity in the regime of high field science. We report here some of the relevant work investigated in this field and predicted further scalings and possibilities for XFEL pulse amplification.展开更多
In this paper, we report the ground state properties i.e. electron momentum density and X-ray structure factors of fcc-copper are presented. The Am241 Compton spectrometer, which uses 59.54 keV gamma-rays, has been us...In this paper, we report the ground state properties i.e. electron momentum density and X-ray structure factors of fcc-copper are presented. The Am241 Compton spectrometer, which uses 59.54 keV gamma-rays, has been used for the Compton profile measurement. To compare the experimental data, the Compton profiles within the framework of linear combination of atomic orbitals (LCAO) method using Hartree–Fock (HF), density functional (DF) and hybrid B3PW schemes embodied in the CRYSTAL06 code have been computed. Among the various theoretical calculations, it is found that the present experimental data is in very good agreement with the hybrid B3PW scheme. A real-space analysis of the experimental Compton profile shows the metal-like behavior of copper The structure factors for copper are computed using hybrid B3PW scheme and compared with available experimental and theoretical data.展开更多
基金supported by the National Natural Science Foundation of China (Nos.11875146,U1932143)National Key Research and Development Program of China (No.2020YFE0202002)。
文摘This study presents an electronics system for cosmic X-ray polarization detection(CXPD).The CXPD was designed as a high-sensitivity soft X-ray polarimeter with a measurement energy range of 2-10 keV carried by a CubeSat.A stable and functionally complete electronics system under power and space constraints is a key challenge.The complete CXPD electronics system(CXPDES)comprises hardware and firmware.CXPDES adopts a three-layer electronic board structure based on functionality and available space.Two gas pixel detectors(GPDs)were placed on the top layer board,and CXPDES provided the GPDs with voltages up to-4000 V.Each GPD signal was digitized,compressed,encoded,and stored before being transmitted to the ground.The CXPDES provided stable and high-speed communication based on a scheme that separated command and data transmission,and it supports the CXPDES in-orbit upgrade.In addition,environmental monitors,silicon photomultiplier(SiPM)triggers,power management,GPDs configuration,and mode switches were included in the overall operating logic of the CXPDES.The results obtained by testing the CXPDES showed that it satisfied all the requirements of CXPD.The CXPDES provides design experience and technological readiness for future large-area X-ray polarimetry missions.
文摘OBJECTIVE: To observe the distribution of copper in the subcellular structure for the understanding of primary pathogenesis of hepatolenticular degeneration (HLD). METHODS: Skin fibroblasts taken from HLD patients were cultured as an in vitro model of HLD, and the control cells taken from healthy volunteers were clutured in the same way. The distribution of copper inside and outside of lysosomes in fibroblasts was detected by quantitative electron probe X-ray microanalysis. The relationship between the subcellular location of copper and the genotype of the patients, and relationship between the distribution of copper and the course of the disease were analyzed. RESULTS: The content of Cu^(2+) inside lysosomes of HLD cells (14.6±2.1 mmol/kg) and of heterozygote cells (11.6±0.6 mmol/kg) was higher than that of normal cells (4.5±1.2 mmol/kg) (P<0.01). The content of Cu^(2+) outside lysosomes of HLD cells (17.5±4.2 mmol/kg) and of heterozygote cells (12.0±0.9 mmol/kg) was higher than that of normal cells (4.7±1.2 mmol/kg) (P<0.01). The distribution of copper in the subcellular structure was correlated with disease courses of HLD patients. With the progression of the disease, more copper was deposited in lysosomes (r=0.85, P<0.01). The content of copper in the diffused cytoplasmic compartment in HLD cells was correlated with that of sulfur (r=0.86, P<0.05), but not in heterozygote and normal cells. CONCLUSIONS: In the early stage of HLD, copper is accumulated outside lysosome, which is paralleled with increase of metallothionein-like proteins (copper and sulfur-binding proteins). With the development of the disease, more copper is deposited inside lysosome than outside lysosome. We conclude that the up-regulation expression of copper and sulfur-binding proteins and copper accumulation in lysosomes may play an important role in lowering the ATP7B gene mutation-induced toxic effects of free copper on the cell.
文摘Distributed X-ray sources comprise a single vacuum chamber containing multiple X-ray sources that are triggered and emit X-rays at a specific time and location. This process facilitates an application for innovative system concepts in X-ray and computer tomography. This paper proposes a novel electron beam focusing, shaping,and deflection electron gun for distributed X-ray sources.The electron gun uses a dispenser cathode as an electron emitter, a mesh grid to control emission current, and two electrostatic lenses for beam shaping, focusing, and deflection. Novel focusing and deflecting electrodes were designed to increase the number of focal spots in the distributed source. Two identical half-rectangle opening electrodes are controlled by adjusting the potential of the two electrodes to control the electron beam trajectory, and then, multifocal spots are obtained on the anode target. The electron gun can increase the spatial density of the distributed X-ray sources, thereby improving the image quality. The beam experimental results show that the focal spot sizes of the deflected(deflected amplitude 10.5 mm)and non-deflected electron beams at full width at half maximum are 0.80 mm 90.50 mm and 0.55 mm 90.40 mm, respectively(anode voltage 160 kV; beam current 30 mA). The imaging experimental results demonstrate the excellent spatial resolution and time resolution of an imaging system built with the sources, which has an excellent imaging effect on a field-programmable gate array chip and a rotating metal disk.
基金supported by the National Natural Science Foundation of China(Grant No.11205154)
文摘The readout electronics for a prototype soft X-ray spectrometer based on silicon drift detector(SDD),for precisely measuring the energy and arrival time of X-ray photons is presented in this paper.The system mainly consists of two parts,i.e.,an analog electronics section(including a pre-amplifier,a signal shaper and filter,a constant fraction timing circuit,and a peak hold circuit)and a digital electronics section(including an ADC and a TDC).Test results with X-ray sources show that an energy dynamic range of 1-10 keV with an integral nonlinearity of less than 0.1%can be achieved,and the energy resolution is better than 160 eV @ 5.9 keV FWHM.Using a waveform generator,test results also indicate that time resolution of the electronics system is about 3.7 ns,which is much less than the transit time spread of SDD(<100 ns)and satisfies the requirements of future applications.
基金supported by the National Basic Research Program of China (Grant No. 2010CB923301)the National Natural Science Foundation of China (GrantNos. 11327404 and 11174268)
文摘An ultra-high vacuum (UHV) compatible electron spectrometer employing a double toroidal analyzer has been de- veloped. It is designed to be combined with a custom-made scanning tunneling microscope (STM) to study the spatially localized electron energy spectrum on a surface. A tip-sample system composed of a piezo-driven field-emission tungsten tip and a sample of highly ordered pyrolytic graphite (HOPG) is employed to test the performance of the spectrometer. Two-dimensional images of the energy-resolved and angle-dispersed electrons backscattered from the surface of HOPG are obtained, the performance is optimized and the spectrometer is calibrated. A complete electron energy loss spectrum covering the elastic peak to the secondary electron peaks for the HOPG surface, acquired at a tip voltage of -140 V and a sample current of 0.5 pA, is presented, demonstrating the viability of the spectrometer.
基金the Shanghai Soft X-ray Free-Electron Laser Facility beamline projectionfunded by the Major State Basic Research Development Program of China(No.2017YFA0504802)+1 种基金Strategic Priority Research Program of the Chinese Academy of Sciences(No.XDB 37040303)National Natural Science Foundation of China(No.21727817).
文摘The Shanghai soft X-ray free-electron laser(SXFEL)user facility project started in 2016 and is expected to be open to users by 2022.It aims to deliver ultra-intense coherent femtosecond X-ray pulses to five endstations covering a range of 100–620 eV for ultrafast X-ray science.Two undulator lines are designed and constructed,based on different lasing modes:self-amplified spontaneous emission and echo-enabled harmonic generation.The coherent scattering and imaging(CSI)endstation is the first of five endstations to be commissioned online.It focuses on high-resolution single-shot imaging and the study of ultrafast dynamic processes using coherent forward scattering techniques.Both the single-shot holograms and coherent diffraction patterns were recorded and reconstructed for nanoscale imaging,indicating the excellent coherence and high peak power of the SXFEL and the possibility of‘‘diffraction before destruction’’experiments at the CSI endstation.In this study,we report the first commissioning results of the CSI endstation.
文摘Understanding electronic structure is crucial to enhance the battery performance. Soft X-ray spectroscopy(SXS) is one of the most effective methods to provide direct probe of electronic states. Here, spectroscopic measurements of transition metal 3 d and oxygen 2 p states are simply reviewed. Then, we mainly focus on the perspective of the development direction of modern SXS techniques. Although the true power of recently developed high efficiency mapping of resonant inelastic X-ray scattering(m RIXS) has been apparent for materials and chemistry studies, great challenges remain for mRIXS spectroscopic interpretation, and the understanding of the battery materials on novel redox activities remains elusive.
文摘The bauxite mineral obtained from Araku, Vishakapatnam district of Andhra Pradesh, India is used in the present work. Structural characterization was performed by X-ray diffraction (XRD). The mineral was found to be gibbsite in phase. The transitional metal ions present were investigated using electron paramagnetic resonance (EPR) and optical absorption spectra. The EPR results suggest that Fe3+ has replaced Al3+ in the unit cell of bauxite. The optical absorption spectrum is due to Fe3+ which indicates that it is in distorted octahedral environment. The near-infrared (NIR) spectrum is due to water fundamentals and combination overtones, which confirm the formula of the compound. The impurities in the mineral are identified using spectroscopic techniques.
基金Supported by the Basic Scientific Fund for National Public Research Institutes of China(Nos.GY02-2011T10,2015P07)the Qingdao Talent Program(No.13-CX-20)+1 种基金the National Natural Science Foundation of China(Nos.31100567,41176061)the National Natural Science Foundation for Creative Groups(No.41521064)
文摘Detection of sulfur-oxidizing bacteria has largely been dependent on targeted gene sequencing technology or traditional cell cultivation, which usually takes from days to months to carry out. This clearly does not meet the requirements of analysis for time-sensitive samples and/or complicated environmental samples. Since energy-dispersive X-ray spectrometry(EDS) can be used to simultaneously detect multiple elements in a sample, including sulfur, with minimal sample treatment, this technology was applied to detect sulfur-oxidizing bacteria using their high sulfur content within the cell. This article describes the application of scanning electron microscopy imaging coupled with EDS mapping for quick detection of sulfur oxidizers in contaminated environmental water samples, with minimal sample handling. Scanning electron microscopy imaging revealed the existence of dense granules within the bacterial cells, while EDS identified large amounts of sulfur within them. EDS mapping localized the sulfur to these granules. Subsequent 16S rRNA gene sequencing showed that the bacteria detected in our samples belonged to the genus Chromatium, which are sulfur oxidizers. Thus, EDS mapping made it possible to identify sulfur oxidizers in environmental samples based on localized sulfur within their cells, within a short time(within 24 h of sampling). This technique has wide ranging applications for detection of sulfur bacteria in environmental water samples.
基金Supported by The RF Ministry of Health within government-mandated program for FSBI Russian Ilizarov Scientific Center "Restorative Traumatology and Orthopaedics"(RISC"RTO") for Scientific Research,No.01201155770
文摘AIM To develop methods of articular cartilage preparation for X-ray-electron probe microanalysis and to study its elements content in experimental osteoarthrosis.METHODS Twenty dogs aged 2-8 years were divided in research(aged 2 years, induction of osteoarthrosis-IOA) and intact group. Intact group included three subgroups(aged 2, 5 and 8 years). Samples of cartilage after araldite saturation and pouring were partially cut into semithin sections stained with methylene blue and with methylene blue-basic fuchsin. Their smooth surfaces were investigated by X-ray-electron probe microanalysis. Spatial distribution of sulfur, calcium and phosphorus and their concentrations(weight %) were investigated.RESULTS X-ray electron probe microanalysis revealed non-uniformsulfur distribution in cartilage of intact animals: Its content increases from superficial zone to deep one, this regularity was preserved in animals with IOA. Differences of IOA with spontaneous chondropathy were revealed. Spontaneous aging was characterized by calcium and phosphorus storage in deep and calcified zones and compensatory increase of sulfated glycosaminoglycans in intermediate and deep cartilage zones as evidenced by the metachromatic reaction and microanalysis data. Unlike spontaneous chondropathy connected with aging in experimentally stimulated osteoarthrosis more intensive storage of calcium but minor phosphorus in intermediate zone were marked. In IOA the calcified cartilage thinning and osteoclastic resorption are apparent with few changes of elements composition; the only difference from control is minority phosphorus content.CONCLUSION The obtained results demonstrate specific tricks of X-ray electron probe microanalysis and its possibility in the research of mechanisms of articular cartilage alterations in osteoarthrosis.
文摘We measured electron temperatures through a hollow cathode-type discharge tube using several different floating probe methods. This method detected a shift in the floating potential when an AC voltage was applied to a probe through an intermediary blocking capacitor. The shift in the floating potential is described as a function of the electron temperature and the applied AC voltage. In this study, the effects of the frequency and waveform on the electron temperatures were systematically investigated. The electron temperature measured when using the floating probe method with applied sinusoidal and triangular voltages was lower than that measured with an applied rectangular voltage.The value in the high frequency range was close to that of the tail electron temperature.
文摘This study presents a novel floating probe method to measure electron temperatures using a hollow cathode-type discharge tube. The proposed method detects a shift in the floating potential when an AC voltage is applied to a probe through an intermediary blocking capacitor. The shift in the floating potential is described as a function of the electron temperature and the applied AC voltage. The floating probe method is simpler than the Langmuir probe method because it does not require the measurement of volt-ampere characteristics. As the input AC voltage increases, the electron temperature converges. The electron temperature measured using the floating probe method with an applied sinusoidal voltage shows a value close to the first (tail) electron temperature in the range of the floating potential.
基金supported by the Director,Office of Science,Office of Basic Energy Sciences,of the U.S.Department of Energy under Contract No.DE-AC02-05CH11231supported by the LDRD program at the Lawrence Berkeley National Laboratory
文摘The formidable challenge of developing high-performance battery system stems from the complication of battery operations, both mechanically and electronically. In the electrodes and at the electrode-electrolyte interfaces, chemical reactions take place with evolving electron states. In addition to the extensive studies of material synthesis, electrochem- ical, structural, and mechanical properties, soft x-ray spectroscopy provides unique opportunities for revealing the critical electron states in batteries. This review discusses some of the recent soft x-ray spectroscopic results on battery binder, transition-metal based positive electrodes, and the solid-electrolyte-interphase. By virtue of soft x-ray's sensitivity to electron states, the electronic property, the redox during electrochemical operations, and the chemical species of the interphases could be fingerprinted by soft x-ray spectroscopy. Understanding and innovating battery technologies need a multimodal approach, and soft x-ray spectroscopy is one of the incisive tools to probe the chemical and physical evolutions in batteries.
基金The project supported by National Natural Science Foundation of China under Grant No, 10375083 and the Special Foundation for State Key Basic Research Program of China under Grant No. TG1999075206-2
文摘Abstract Linear Thomson scattering of a short pulse laser by relativistic electron has been investigated using computer simulations. It is shown that scattering of an intense laser pulse of -33 fs full width at half maximum, with an electron of γ0 = 10 initial energy, generates an ultrashort, pulsed radiation of 76 attoseconds with a photon wavelength of 2.5 nm in the backward direction. The scattered radiation generated by a highly relativistic electron has superior quality in terms of its pulse width and angular distribution in comparison to the one generated by lower relativistic energy electron.
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the National High-Tech ICF Committee in Chinathe National Natute Science Foundation of China !(No.19735002)the Fund of C
文摘The influence of electron thermal conductivity on the laser x-ray conversion in the coupling of 3w. laser with Au plane target has been investigated by using a non-LTE radiation hydrodynamic code. The non-local electron thermal conductivity is introduced and compared with the other two kinds of the flux-limited Spitzer-Harm description. The results show that the non-local thermal conductivity causes the increase of the laser x-ray conversion efficiency and important changes of the plasma state and coupling feature.
基金supported by National Natural Science Foundation of China (Nos.10775041,10675124)Youth Science FundsChinese Academy of Sciences,and the JSPS-CAS Core-University Program in the field of Plasma and Nuclear Fusion
文摘Two soft X-ray pulse height analysis (PHA) systems, based on silicon drift detec- tor (SDD), were established on the experimental advanced superconducting tokamak (EAST) to measure spectrum of soft X-ray emission. In this paper, the soft X-ray PHA systems on EAST are introduced and some experimental results of electron temperature in EAST obtained from the soft X-ray PHA diagnostic are presented.
基金Project supported by the National Natural Science Foundation of China (Grant No. 11275071 ).
文摘The experimental data of Mαβ X-ray production cross sections for Pb and Bi by 9–40 keV electron impact have been given. Thin films with thick carbon substrates are used in the experiment. The effects of target structure on the Mαβ X-ray production cross sections are corrected by using the Monte Carlo method. The corrected experimental data are compared with calculated cross sections in terms of the distorted-wave Born approximation(DWBA) theory. The measured Mαβ X-ray production cross sections for Pb and Bi are lower than the DWBA calculations. The atomic relaxation parameters used in comparing the DWBA values with experimental results affect the degree of difference.
文摘In view of X-ray Free Electron Laser (XFEL) intensity prospects, we reviewed the past and recent work in view of amplification of powerful XFEL laser pulse to achieve intensity in the regime of high field science. We report here some of the relevant work investigated in this field and predicted further scalings and possibilities for XFEL pulse amplification.
文摘In this paper, we report the ground state properties i.e. electron momentum density and X-ray structure factors of fcc-copper are presented. The Am241 Compton spectrometer, which uses 59.54 keV gamma-rays, has been used for the Compton profile measurement. To compare the experimental data, the Compton profiles within the framework of linear combination of atomic orbitals (LCAO) method using Hartree–Fock (HF), density functional (DF) and hybrid B3PW schemes embodied in the CRYSTAL06 code have been computed. Among the various theoretical calculations, it is found that the present experimental data is in very good agreement with the hybrid B3PW scheme. A real-space analysis of the experimental Compton profile shows the metal-like behavior of copper The structure factors for copper are computed using hybrid B3PW scheme and compared with available experimental and theoretical data.