The layout and characteristics of the hard X-ray spectroscopy beamline(BL11B)at the Shanghai synchrotron radiation facility are described herein.BL11B is a bending-magnet beamline dedicated to conventional and millise...The layout and characteristics of the hard X-ray spectroscopy beamline(BL11B)at the Shanghai synchrotron radiation facility are described herein.BL11B is a bending-magnet beamline dedicated to conventional and millisecond-scale quick-scanning X-ray absorption fine structures.It is equipped with a cylindrical collimating mirror,a double-crystal monochromator comprising Si(111)and Si(311),a channel-cut quick-scanning Si(111)monochromator,a toroidal focusing mirror,and a high harmonics rejection mirror.It can provide 5-30 keV of X-rays with a photon flux of~5×10^(11)photons/s and an energy resolution of~1.31×10^(-4)at 10 keV.The performance of the beamline can satisfy the demands of users in the fields of catalysis,materials,and environmental science.This paper presents an overview of the beamline design and a detailed description of its performance and capabilities.展开更多
The explosive reaction degree and protection from explosions are concerns in the military field.In this work,the reaction degree of the composition B explosive was investigated experimentally.Multi-layered compound st...The explosive reaction degree and protection from explosions are concerns in the military field.In this work,the reaction degree of the composition B explosive was investigated experimentally.Multi-layered compound structures were used as barriers to weaken the blast loads.A comprehensive experiment using a high-speed camera and image processing techniques,side witness plates,and bottom witness plates was presented.Using the experimental fragment velocities,fragment piercing patterns,and damage characteristics,the reaction degree of the explosive impeded by different multi-layered compound structures could be precisely differentiated.Reaction parameters of the explosive obstructed by compound structures were obtained by theoretical analysis and numerical simulations.Unlike the common method in which the explosive reaction degree is only distinguished based on the initial pressure amplitude transmitted into the explosive,a following shock wave reflected from the side steel casing was also considered.Different detonation growth paths in the explosive formed.Therefore,all these shock wave propagation characteristics must be considered to analyze the explosive response impeded by compound structures.展开更多
BACKGROUND:The latest sepsis definition includes both infection and organ failure,as evidenced by the sequential organ failure assessment(SOFA)score.However,the applicability of the pediatric SOFA score(pSOFA)is not y...BACKGROUND:The latest sepsis definition includes both infection and organ failure,as evidenced by the sequential organ failure assessment(SOFA)score.However,the applicability of the pediatric SOFA score(pSOFA)is not yet determined.This study evaluated the effectiveness of both pSOFA and system inflammatory reaction syndrome(SIRS)scores in predicting sepsis-related pediatric deaths.METHODS:This is a retrospective multi-center cohort study including hospitalized patients<18 years old with diagnosed or not-yet-diagnosed infections.Multivariate analyses were carried out to evaluate risk factors for in-hospital mortality.According to Youden index(YI),three sub-categories of pSOFA were screened out and a new simplified pSOFA score(spSOFA)was formed.The effectiveness and accuracy of prediction of pSOFA,SIRS and spSOFA was retrieved from the area under the receiver operating characteristic curve(AUROC)and Delong’s test.RESULTS:A total of 1,092 participants were eligible for this study,and carried a 23.4%in-hospital mortality rate.The 24-h elevated pSOFA score(24 h-pSOFA),bloodstream infection,and mechanical ventilation(MV)requirement were major risk factors associated with sepsis-related deaths.The AUROC analysis confirmed that the spSOFA provided good predictive capability in sepsis-related pediatric deaths,relative to the 24 h-pSOFA and SIRS.CONCLUSIONS:The pSOFA score performed better than SIRS in diagnosing infected children with high mortality risk.However,it is both costly and cumbersome.We,therefore,proposed spSOFA to accurately predict patient outcome,without the disadvantages.Nevertheless,additional investigations,involving a large sample population,are warranted to confirm the conclusion of this study.展开更多
A new X-ray absorption fine structure(XAFS)data-collection system based on the Experimental Physics and Industrial Control System software environment has been established at the BL14W1 beamline of the Shanghai Synchr...A new X-ray absorption fine structure(XAFS)data-collection system based on the Experimental Physics and Industrial Control System software environment has been established at the BL14W1 beamline of the Shanghai Synchrotron Radiation Facility. The system provides for automatic sequential analysis of multiple samples for continuous high-throughput(HT) measurements. Specifically, 8 sample pellets are loaded into an alumina holder,and a high-precision two-dimensional translation stage is programmed to switch these samples automatically for collecting the XAFS spectrum of each sample in sequence.Experimenters implement HT measurements via a graphical user interface developed with Control System Studio.Finally, the successful operation of the HT XAFS system is demonstrated by running experiments on two groups of copper–ceria catalysts, each of which contains 8 different powder samples.展开更多
Numerous techniques have been developed to determine the bioavailability of minerals.Each method has specific detection objects with certain procedures to assure the results.This review focuses on a comprehensivecompa...Numerous techniques have been developed to determine the bioavailability of minerals.Each method has specific detection objects with certain procedures to assure the results.This review focuses on a comprehensivecomparison of the applications,advantages,and critical control points of these techniques.The commonly used approaches for assessing mineral bioavailability can be divided into three categories-chemical methods,in vitro models and in vivo tests.Chemical methods are first developed,and mainly simulating the digestion environment to give a rough prediction of mineral bioavailability.In vitro models mainly used different cells to simulate the process and environment of food digestion to assess the availability of minerals.In vivo tests are employing complex models to observe the bioavailability of minerals after complicated digestive process in animal models or human volunteers.This review summarizes the critical points of establishment of these relevant models,compares the advantages and limitations among three categories.Although no single bioavailability method is ideal for all micronutrients,certain methods under proper operation can indeed be employed to minimize the differences between simulated results and reality for effective evaluation of the bioavailability of minerals.展开更多
For composite electromagnetic(EM)scattering from rough surface and target above it in near-field condition,modified shooting and bouncing ray(SBR)method and integral equation method(IEM),which are analytic methods com...For composite electromagnetic(EM)scattering from rough surface and target above it in near-field condition,modified shooting and bouncing ray(SBR)method and integral equation method(IEM),which are analytic methods combined with two-scale model for rough surface,are proposed to solve the composite near-field scattering problems.And the modified method is verified in effectiveness and accuracy by comparing the simulation results with measured results.Finally,the composite near-fielding scattering characteristics of a slanted plane and rough water surface below are obtained by using the proposed methods,and the dynamic tendency of composite scattering characteristics versus near-fielding distance is analyzed,which may have practical contribution to engineering programs in need of radar targets near-field characteristics under extra-low-altitude conditions.展开更多
Due to the characteristics of intermittent photovoltaic power generation and power fluctuations in distributed photovoltaic power generation,photovoltaic grid-connected systems are usually equipped with energy storage...Due to the characteristics of intermittent photovoltaic power generation and power fluctuations in distributed photovoltaic power generation,photovoltaic grid-connected systems are usually equipped with energy storage units.Most of the structures combined with energy storage are used as the DC side.At the same time,virtual synchronous generators have been widely used in distributed power generation due to their inertial damping and frequency and voltage regulation.For the PV-storage grid-connected system based on virtual synchronous generators,the existing control strategy has unclear function allocation,fluctuations in photovoltaic inverter output power,and high requirements for coordinated control of PV arrays,energy storage units,and photovoltaic inverters,which make the control strategy more complicated.In order to solve the above problems,a control strategy for PV-storage grid-connected system based on a virtual synchronous generator is proposed.In this strategy,the energy storage unit implements maximum power point tracking,and the photovoltaic inverter implements a virtual synchronous generator algorithm,so that the functions implemented by each part of the system are clear,which reduces the requirements for coordinated control.At the same time,the smooth power command is used to suppress the fluctuation of the output power of the photovoltaic inverter.The simulation validates the effectiveness of the proposed method from three aspects:grid-connected operating conditions,frequency-modulated operating conditions,and illumination sudden-drop operating condition.Compared with the existing control strategies,the proposed method simplifies the control strategies and stabilizes the photovoltaic inverter fluctuation in the output power of the inverter.展开更多
In X-ray absorption fine structure(XAFS) experiments,Soller slits are widely used as filter devices in order to improve the signal to noise ratio.Performing high accuracy manual focusing operations is a time-consuming...In X-ray absorption fine structure(XAFS) experiments,Soller slits are widely used as filter devices in order to improve the signal to noise ratio.Performing high accuracy manual focusing operations is a time-consuming process;therefore,this work introduces an automatic focusing method for Soller slits in multi-element fluorescence detectors.This method establishes a relation model between the fluorescence intensity distribution and the coordinates of the fluorescence excitation point.According to this relation model,the actual coordinates of the fluorescence excitation point can be deduced from the detected fluorescence intensity distribution and used in focusing operations.This method has proven to be feasible in an XAFS experiment at the BL14W1 beamline of the Shanghai Synchrotron Radiation Facility.展开更多
Numerical simulation tools based on potential-flow theory and/or Morison’s equation are widely used for predicting the hydrodynamic responses of floating offshore wind platforms.In general,these simplified approaches...Numerical simulation tools based on potential-flow theory and/or Morison’s equation are widely used for predicting the hydrodynamic responses of floating offshore wind platforms.In general,these simplified approaches are used for the analysis under operational conditions,albeit with a carefully selected approach to account for viscous effects.Nevertheless,due to the limit hydrodynamic modelling to linear and weakly nonlinear models,these approaches severely underpredict the low-frequency nonlinear wave loads and dynamic responses of a semisubmersible.They may not capture important nonlinearities in severe sea states.For the prediction of wave-induced motions and loads on a semisubmersible,this work systematically compares a fully nonlinear viscous-flow solver and a hybrid model combining the potential-flow theory with Morison-drag loads in steep waves.Results show that when nonlinear phenomena are not dominant,the results obtained by the hybrid model and the high-fidelity method show reasonable agreement,while larger discrepancies occur for highly nonlinear regular waves.Specifically,regular waves with various steepness over different frequencies are focused in the present study,which supplements the understanding in applicability of these two groups of method.展开更多
Background:To develop an effective model of predicting fatal outcomes in the severe coronavirus disease 2019(COVID-19)patients.Methods:Between February 20,2020 and April 4,2020,consecutive confirmed 2541 COVID-19 pati...Background:To develop an effective model of predicting fatal outcomes in the severe coronavirus disease 2019(COVID-19)patients.Methods:Between February 20,2020 and April 4,2020,consecutive confirmed 2541 COVID-19 patients from three designated hospitals were enrolled in this study.All patients received chest computed tomography(CT)and serological examinations at admission.Laboratory tests included routine blood tests,liver function,renal function,coagulation profile,C-reactive protein(CRP),procalcitonin(PCT),interleukin-6(IL-6),and arterial blood gas.The SaO2 was measured using pulse oxygen saturation in room air at resting status.Independent high-risk factors associated with death were analyzed using Cox proportional hazard model.A prognostic nomogram was constructed to predict the survival of severe COVID-19 patients.Results:There were 124 severe patients in the training cohort,and there were 71 and 76 severe patients in the two independent validation cohorts,respectively.Multivariate Cox analysis indicated that age≥70 years(HR=1.184,95%CI 1.061–1.321),panting(breathing rate≥30/min)(HR=3.300,95%CI 2.509–6.286),lymphocyte count<1.0×109/L(HR=2.283,95%CI 1.779–3.267),and interleukin-6(IL-6)>10pg/ml(HR=3.029,95%CI 1.567–7.116)were independent high-risk factors associated with fatal outcome.We developed the nomogram for identifying survival of severe COVID-19 patients in the training cohort(AUC=0.900,95%CI 0.841–0.960,sensitivity 95.5%,specificity 77.5%);in validation cohort 1(AUC=0.811,95%CI 0.763–0.961,sensitivity 77.3%,specificity 73.5%);in validation cohort 2(AUC=0.862,95%CI 0.698–0.924,sensitivity 92.9%,specificity 64.5%).The calibration curve for probability of death indicated a good consistence between prediction by the nomogram and the actual observation.The prognosis of severe COVID-19 patients with high levels of IL-6 receiving tocilizumab were better than that of those patients without tocilizumab both in the training and validation cohorts,but without difference(P=0.105 for training cohort,P=0.133 for validation cohort 1,and P=0.210 for validation cohort 2).Conclusions:This nomogram could help clinicians to identify severe patients who have high risk of death,and to develop more appropriate treatment strategies to reduce the mortality of severe patients.Tocilizumab may improve the prognosis of severe COVID-19 patients with high levels of IL-6.展开更多
文摘The layout and characteristics of the hard X-ray spectroscopy beamline(BL11B)at the Shanghai synchrotron radiation facility are described herein.BL11B is a bending-magnet beamline dedicated to conventional and millisecond-scale quick-scanning X-ray absorption fine structures.It is equipped with a cylindrical collimating mirror,a double-crystal monochromator comprising Si(111)and Si(311),a channel-cut quick-scanning Si(111)monochromator,a toroidal focusing mirror,and a high harmonics rejection mirror.It can provide 5-30 keV of X-rays with a photon flux of~5×10^(11)photons/s and an energy resolution of~1.31×10^(-4)at 10 keV.The performance of the beamline can satisfy the demands of users in the fields of catalysis,materials,and environmental science.This paper presents an overview of the beamline design and a detailed description of its performance and capabilities.
文摘目的:研究beta-B2晶状体蛋白(CRYBB2)缺失对小鼠晶状体自噬的影响。方法:取6月龄野生型(WT)和Crybb2基因敲除型(Crybb2^KO)小鼠各6只,取晶状体组织,透射电子显微镜观察各组小鼠晶状体组织自噬的改变,用Western blot法检测两组小鼠自噬相关蛋白的相对表达量。结果:透射电子显微镜下观察发现,与WT小鼠相比,Crybb2KO小鼠晶状体核区线粒体累积明显,皮质区自噬小体数量增多。Western blot结果显示,Crybb2KO小鼠晶状体组织LC3B表达显著低于WT小鼠(0.09±0.01 vs 0.26±0.05),P62及p-mTOR表达(0.64±0.09和0.41±0.03)显著高于WT小鼠(0.43±0.07和0.27±0.02)。结论:CRYBB2晶状体蛋白缺失会影响晶状体自噬,其机制可能与mTOR信号通路的自噬相关,最终导致白内障产生。
基金The authors are very grateful for the support received from the National Natural Science Foundation of China(No.11872121).
文摘The explosive reaction degree and protection from explosions are concerns in the military field.In this work,the reaction degree of the composition B explosive was investigated experimentally.Multi-layered compound structures were used as barriers to weaken the blast loads.A comprehensive experiment using a high-speed camera and image processing techniques,side witness plates,and bottom witness plates was presented.Using the experimental fragment velocities,fragment piercing patterns,and damage characteristics,the reaction degree of the explosive impeded by different multi-layered compound structures could be precisely differentiated.Reaction parameters of the explosive obstructed by compound structures were obtained by theoretical analysis and numerical simulations.Unlike the common method in which the explosive reaction degree is only distinguished based on the initial pressure amplitude transmitted into the explosive,a following shock wave reflected from the side steel casing was also considered.Different detonation growth paths in the explosive formed.Therefore,all these shock wave propagation characteristics must be considered to analyze the explosive response impeded by compound structures.
文摘BACKGROUND:The latest sepsis definition includes both infection and organ failure,as evidenced by the sequential organ failure assessment(SOFA)score.However,the applicability of the pediatric SOFA score(pSOFA)is not yet determined.This study evaluated the effectiveness of both pSOFA and system inflammatory reaction syndrome(SIRS)scores in predicting sepsis-related pediatric deaths.METHODS:This is a retrospective multi-center cohort study including hospitalized patients<18 years old with diagnosed or not-yet-diagnosed infections.Multivariate analyses were carried out to evaluate risk factors for in-hospital mortality.According to Youden index(YI),three sub-categories of pSOFA were screened out and a new simplified pSOFA score(spSOFA)was formed.The effectiveness and accuracy of prediction of pSOFA,SIRS and spSOFA was retrieved from the area under the receiver operating characteristic curve(AUROC)and Delong’s test.RESULTS:A total of 1,092 participants were eligible for this study,and carried a 23.4%in-hospital mortality rate.The 24-h elevated pSOFA score(24 h-pSOFA),bloodstream infection,and mechanical ventilation(MV)requirement were major risk factors associated with sepsis-related deaths.The AUROC analysis confirmed that the spSOFA provided good predictive capability in sepsis-related pediatric deaths,relative to the 24 h-pSOFA and SIRS.CONCLUSIONS:The pSOFA score performed better than SIRS in diagnosing infected children with high mortality risk.However,it is both costly and cumbersome.We,therefore,proposed spSOFA to accurately predict patient outcome,without the disadvantages.Nevertheless,additional investigations,involving a large sample population,are warranted to confirm the conclusion of this study.
基金supported by the National Natural Science Foundation of China under Grant No.21373259
文摘A new X-ray absorption fine structure(XAFS)data-collection system based on the Experimental Physics and Industrial Control System software environment has been established at the BL14W1 beamline of the Shanghai Synchrotron Radiation Facility. The system provides for automatic sequential analysis of multiple samples for continuous high-throughput(HT) measurements. Specifically, 8 sample pellets are loaded into an alumina holder,and a high-precision two-dimensional translation stage is programmed to switch these samples automatically for collecting the XAFS spectrum of each sample in sequence.Experimenters implement HT measurements via a graphical user interface developed with Control System Studio.Finally, the successful operation of the HT XAFS system is demonstrated by running experiments on two groups of copper–ceria catalysts, each of which contains 8 different powder samples.
文摘Numerous techniques have been developed to determine the bioavailability of minerals.Each method has specific detection objects with certain procedures to assure the results.This review focuses on a comprehensivecomparison of the applications,advantages,and critical control points of these techniques.The commonly used approaches for assessing mineral bioavailability can be divided into three categories-chemical methods,in vitro models and in vivo tests.Chemical methods are first developed,and mainly simulating the digestion environment to give a rough prediction of mineral bioavailability.In vitro models mainly used different cells to simulate the process and environment of food digestion to assess the availability of minerals.In vivo tests are employing complex models to observe the bioavailability of minerals after complicated digestive process in animal models or human volunteers.This review summarizes the critical points of establishment of these relevant models,compares the advantages and limitations among three categories.Although no single bioavailability method is ideal for all micronutrients,certain methods under proper operation can indeed be employed to minimize the differences between simulated results and reality for effective evaluation of the bioavailability of minerals.
基金Project supported by the National Natural Science Foundation of China(Grant No.61372033).
文摘For composite electromagnetic(EM)scattering from rough surface and target above it in near-field condition,modified shooting and bouncing ray(SBR)method and integral equation method(IEM),which are analytic methods combined with two-scale model for rough surface,are proposed to solve the composite near-field scattering problems.And the modified method is verified in effectiveness and accuracy by comparing the simulation results with measured results.Finally,the composite near-fielding scattering characteristics of a slanted plane and rough water surface below are obtained by using the proposed methods,and the dynamic tendency of composite scattering characteristics versus near-fielding distance is analyzed,which may have practical contribution to engineering programs in need of radar targets near-field characteristics under extra-low-altitude conditions.
基金supported by National Natural Science Foundation of China Key program(51937003)。
文摘Due to the characteristics of intermittent photovoltaic power generation and power fluctuations in distributed photovoltaic power generation,photovoltaic grid-connected systems are usually equipped with energy storage units.Most of the structures combined with energy storage are used as the DC side.At the same time,virtual synchronous generators have been widely used in distributed power generation due to their inertial damping and frequency and voltage regulation.For the PV-storage grid-connected system based on virtual synchronous generators,the existing control strategy has unclear function allocation,fluctuations in photovoltaic inverter output power,and high requirements for coordinated control of PV arrays,energy storage units,and photovoltaic inverters,which make the control strategy more complicated.In order to solve the above problems,a control strategy for PV-storage grid-connected system based on a virtual synchronous generator is proposed.In this strategy,the energy storage unit implements maximum power point tracking,and the photovoltaic inverter implements a virtual synchronous generator algorithm,so that the functions implemented by each part of the system are clear,which reduces the requirements for coordinated control.At the same time,the smooth power command is used to suppress the fluctuation of the output power of the photovoltaic inverter.The simulation validates the effectiveness of the proposed method from three aspects:grid-connected operating conditions,frequency-modulated operating conditions,and illumination sudden-drop operating condition.Compared with the existing control strategies,the proposed method simplifies the control strategies and stabilizes the photovoltaic inverter fluctuation in the output power of the inverter.
基金supported by National Nature Science Foundation of China(No.11175244)
文摘In X-ray absorption fine structure(XAFS) experiments,Soller slits are widely used as filter devices in order to improve the signal to noise ratio.Performing high accuracy manual focusing operations is a time-consuming process;therefore,this work introduces an automatic focusing method for Soller slits in multi-element fluorescence detectors.This method establishes a relation model between the fluorescence intensity distribution and the coordinates of the fluorescence excitation point.According to this relation model,the actual coordinates of the fluorescence excitation point can be deduced from the detected fluorescence intensity distribution and used in focusing operations.This method has proven to be feasible in an XAFS experiment at the BL14W1 beamline of the Shanghai Synchrotron Radiation Facility.
文摘Numerical simulation tools based on potential-flow theory and/or Morison’s equation are widely used for predicting the hydrodynamic responses of floating offshore wind platforms.In general,these simplified approaches are used for the analysis under operational conditions,albeit with a carefully selected approach to account for viscous effects.Nevertheless,due to the limit hydrodynamic modelling to linear and weakly nonlinear models,these approaches severely underpredict the low-frequency nonlinear wave loads and dynamic responses of a semisubmersible.They may not capture important nonlinearities in severe sea states.For the prediction of wave-induced motions and loads on a semisubmersible,this work systematically compares a fully nonlinear viscous-flow solver and a hybrid model combining the potential-flow theory with Morison-drag loads in steep waves.Results show that when nonlinear phenomena are not dominant,the results obtained by the hybrid model and the high-fidelity method show reasonable agreement,while larger discrepancies occur for highly nonlinear regular waves.Specifically,regular waves with various steepness over different frequencies are focused in the present study,which supplements the understanding in applicability of these two groups of method.
基金the National Natural Science Foundation of China(81502416)to Dr.Yun Yang.
文摘Background:To develop an effective model of predicting fatal outcomes in the severe coronavirus disease 2019(COVID-19)patients.Methods:Between February 20,2020 and April 4,2020,consecutive confirmed 2541 COVID-19 patients from three designated hospitals were enrolled in this study.All patients received chest computed tomography(CT)and serological examinations at admission.Laboratory tests included routine blood tests,liver function,renal function,coagulation profile,C-reactive protein(CRP),procalcitonin(PCT),interleukin-6(IL-6),and arterial blood gas.The SaO2 was measured using pulse oxygen saturation in room air at resting status.Independent high-risk factors associated with death were analyzed using Cox proportional hazard model.A prognostic nomogram was constructed to predict the survival of severe COVID-19 patients.Results:There were 124 severe patients in the training cohort,and there were 71 and 76 severe patients in the two independent validation cohorts,respectively.Multivariate Cox analysis indicated that age≥70 years(HR=1.184,95%CI 1.061–1.321),panting(breathing rate≥30/min)(HR=3.300,95%CI 2.509–6.286),lymphocyte count<1.0×109/L(HR=2.283,95%CI 1.779–3.267),and interleukin-6(IL-6)>10pg/ml(HR=3.029,95%CI 1.567–7.116)were independent high-risk factors associated with fatal outcome.We developed the nomogram for identifying survival of severe COVID-19 patients in the training cohort(AUC=0.900,95%CI 0.841–0.960,sensitivity 95.5%,specificity 77.5%);in validation cohort 1(AUC=0.811,95%CI 0.763–0.961,sensitivity 77.3%,specificity 73.5%);in validation cohort 2(AUC=0.862,95%CI 0.698–0.924,sensitivity 92.9%,specificity 64.5%).The calibration curve for probability of death indicated a good consistence between prediction by the nomogram and the actual observation.The prognosis of severe COVID-19 patients with high levels of IL-6 receiving tocilizumab were better than that of those patients without tocilizumab both in the training and validation cohorts,but without difference(P=0.105 for training cohort,P=0.133 for validation cohort 1,and P=0.210 for validation cohort 2).Conclusions:This nomogram could help clinicians to identify severe patients who have high risk of death,and to develop more appropriate treatment strategies to reduce the mortality of severe patients.Tocilizumab may improve the prognosis of severe COVID-19 patients with high levels of IL-6.
