In the preparation of magnesium by Pidgeon process,the phenomenon slag pellets sticking on the wall of reduction pot always appear,and the glaze sticking on the inner wall of the reduction pot is difficult to remove.T...In the preparation of magnesium by Pidgeon process,the phenomenon slag pellets sticking on the wall of reduction pot always appear,and the glaze sticking on the inner wall of the reduction pot is difficult to remove.The mechanism of this phenomenon is studied in this work by X-ray fluorescence spectrometer(XRF)measurement,electron probe microanalyzer scanning(EPMA)analysis,differential scanning calorimetry(DSC)analysis,and thermodynamic calculations.The main components of the glaze are MgO,Ca_(12)Al_(14)F_(2)O_(32),CaF_(2),CaO,and a small amount of Ca_(4)Si_(2)O_(7)F_(2).The solid-liquid transition temperature of Ca_(12)Al_(14)F_(2)O_(32)and CaF_(2)is close to the production temperature of Pidgeon process,which leads to the bonding between the slag pellets and the pot wall.The loss of CaF_(2)in glaze layer will reduce the total amount of liquid phase and increase the temperature at which Ca_(12)Al_(14)F_(2)O_(32)is completely transformed into liquid phase,which causes glaze layer sticking on the inner wall of the reduction pot.展开更多
BACKGROUND: We aimed to investigate whether the pressure injury risk mediates the association of left ventricular ejection fraction(LVEF) with all-cause death in patients with acute myocardial infarction(AMI) aged 80 ...BACKGROUND: We aimed to investigate whether the pressure injury risk mediates the association of left ventricular ejection fraction(LVEF) with all-cause death in patients with acute myocardial infarction(AMI) aged 80 years or older.METHODS: This retrospective cohort study included 677 patients with AMI aged 80 years or older from a tertiary-level hospital. Pressure injury risk was assessed using the Braden scale at admission, and three risk groups(low/minimal, intermediate, high) were defined according to the overall score of six different variables. LVEF was measured during the index hospitalization for AMI. All-cause death after hospital discharge was the primary outcome.RESULTS: Over a median follow-up period of 1,176 d(interquartile range [IQR], 722–1,900 d), 226(33.4%) patients died. Multivariate Cox regression analysis showed that reduced LVEF was associated with an increased risk of all-cause death only in the high-risk group of pressure injury(adjusted hazard ratios [HR]=1.81, 95% confidence interval [CI]: 1.03–3.20;P=0.040), but not in the low/minimal-(adjusted HR=1.29, 95%CI: 0.80–2.11;P=0.299) or intermediate-risk groups(adjusted HR=1.14, 95%CI: 0.65–2.02;P=0.651). Significant interactions were detected between pressure injury risk and LVEF(adjusted P=0.003). The cubic spline with hazard ratio plot revealed a distinct shaped curve relation between LVEF and all-cause death among different pressure injury risk groups.CONCLUSIONS: In older patients with AMI, the risk of pressure injury mediated the association between LVEF and all-cause death. The classification of older patients for both therapy and prognosis assessment appears to be improved by the incorporation of pressure injury risk assessment into AMI care management.展开更多
The host structure of polymers significantly influences ion transport and interfacial stability of electrolytes,dictating battery cycle life and safety for solid-state lithium metal batteries.Despite promising propert...The host structure of polymers significantly influences ion transport and interfacial stability of electrolytes,dictating battery cycle life and safety for solid-state lithium metal batteries.Despite promising properties of ethylene oxide-based electrolytes,their typical clamp-like coordination geometry leads to crowd solvation sheath and overly strong interactions between Li^(+)and electrolytes,rendering difficult dissociation of Li+and unfavorable solid electrolyte interface(SEI).Herein,we explore weakly solvating characteristics of polyacetal electrolytes owing to their alternately changing intervals between–O–coordinating sites in the main chain.Such structural asymmetry leads to unique distorted helical solvation sheath,and can effectively reduce Li^(+)-electrolyte binding and tune Li^(+)desolvation kinetics in the insitu formed polymer electrolytes,yielding anion-derived SEI and dendrite-free Li electrodeposition.Combining with photoinitiated cationic ring-opening polymerization,polyacetal electrolytes can be instantly formed within 5 min at the surface of electrode,with high segmental chain motion and well adapted interfaces.Such in-situ polyacetal electrolytes enabled more than 1300-h of stable lithium electrodeposition and prolonged cyclability over 200 cycles in solid-state batteries at ambient temperatures,demonstrating the vital role of molecular structure in changing solvating behavior and Li deposition stability for high-performance electrolytes.展开更多
针对维间耦合会影响六维腕力传感器测量精度的问题,提出了基于多输出支持向量回归机(Multi-output support vector regression,MSVR)的解耦算法。以实验室研制的六维腕力传感器为例进行静态标定实验,使用基于MSVR的解耦算法以及传统的...针对维间耦合会影响六维腕力传感器测量精度的问题,提出了基于多输出支持向量回归机(Multi-output support vector regression,MSVR)的解耦算法。以实验室研制的六维腕力传感器为例进行静态标定实验,使用基于MSVR的解耦算法以及传统的基于最小二乘求解标定矩阵的解耦算法对标定数据进行处理分析。实验结果表明,本文提出的解耦算法稳定可靠,能有效抑制维间耦合的干扰,具有较高的解耦精度。展开更多
Traditional ceramic materials are generally brittle and not flexible with high production costs,which seriously hinders their practical applications.Multifunctional nanofiber ceramic aerogels are highly desirable for ...Traditional ceramic materials are generally brittle and not flexible with high production costs,which seriously hinders their practical applications.Multifunctional nanofiber ceramic aerogels are highly desirable for applications in extreme environments,however,the integration of multiple functions in their preparation is extremely challenging.To tackle these challenges,we fabricated a multifunctional SiC@SiO_(2) nanofiber aerogel(SiC@SiO_(2) NFA)with a threedimensional(3D)porous cross-linked structure through a simple chemical vapor deposition method and subsequent heat-treatment process.The as-prepared SiC@SiO_(2) NFA exhibits an ultralow density(~11 mg cm^(-3)),ultra-elastic,fatigue-resistant and refractory performance,high temperature thermal stability,thermal insulation properties,and significant strain-dependent piezoresistive sensing behavior.Furthermore,the SiC@SiO_(2) NFA shows a superior electromagnetic wave absorption performance with a minimum refection loss(RL_(min))value of-50.36 d B and a maximum effective absorption bandwidth(EAB_(max))of 8.6 GHz.The successful preparation of this multifunctional aerogel material provides a promising prospect for the design and fabrication of the cutting-edge ceramic materials.展开更多
基金funded by the China Postdoctoral Sci-ence Foundation(Grant No.2020M682337)Certificate of Postdoctoral Research Grant in Henan Province(Grant No.201903011)National Key Research and Development Program of China(Grant Nos.2016YFB0301001 and 2016YFB0301101).
文摘In the preparation of magnesium by Pidgeon process,the phenomenon slag pellets sticking on the wall of reduction pot always appear,and the glaze sticking on the inner wall of the reduction pot is difficult to remove.The mechanism of this phenomenon is studied in this work by X-ray fluorescence spectrometer(XRF)measurement,electron probe microanalyzer scanning(EPMA)analysis,differential scanning calorimetry(DSC)analysis,and thermodynamic calculations.The main components of the glaze are MgO,Ca_(12)Al_(14)F_(2)O_(32),CaF_(2),CaO,and a small amount of Ca_(4)Si_(2)O_(7)F_(2).The solid-liquid transition temperature of Ca_(12)Al_(14)F_(2)O_(32)and CaF_(2)is close to the production temperature of Pidgeon process,which leads to the bonding between the slag pellets and the pot wall.The loss of CaF_(2)in glaze layer will reduce the total amount of liquid phase and increase the temperature at which Ca_(12)Al_(14)F_(2)O_(32)is completely transformed into liquid phase,which causes glaze layer sticking on the inner wall of the reduction pot.
基金This work was supported by the Key Research and Development Projects of Science&Technology Department of Sichuan Province(2019YFS0351).
文摘BACKGROUND: We aimed to investigate whether the pressure injury risk mediates the association of left ventricular ejection fraction(LVEF) with all-cause death in patients with acute myocardial infarction(AMI) aged 80 years or older.METHODS: This retrospective cohort study included 677 patients with AMI aged 80 years or older from a tertiary-level hospital. Pressure injury risk was assessed using the Braden scale at admission, and three risk groups(low/minimal, intermediate, high) were defined according to the overall score of six different variables. LVEF was measured during the index hospitalization for AMI. All-cause death after hospital discharge was the primary outcome.RESULTS: Over a median follow-up period of 1,176 d(interquartile range [IQR], 722–1,900 d), 226(33.4%) patients died. Multivariate Cox regression analysis showed that reduced LVEF was associated with an increased risk of all-cause death only in the high-risk group of pressure injury(adjusted hazard ratios [HR]=1.81, 95% confidence interval [CI]: 1.03–3.20;P=0.040), but not in the low/minimal-(adjusted HR=1.29, 95%CI: 0.80–2.11;P=0.299) or intermediate-risk groups(adjusted HR=1.14, 95%CI: 0.65–2.02;P=0.651). Significant interactions were detected between pressure injury risk and LVEF(adjusted P=0.003). The cubic spline with hazard ratio plot revealed a distinct shaped curve relation between LVEF and all-cause death among different pressure injury risk groups.CONCLUSIONS: In older patients with AMI, the risk of pressure injury mediated the association between LVEF and all-cause death. The classification of older patients for both therapy and prognosis assessment appears to be improved by the incorporation of pressure injury risk assessment into AMI care management.
基金financially supported by National Natural Science Foundation of China(52003231,22065037)Yunnan Fundamental Research Projects(202201AW070015)。
文摘The host structure of polymers significantly influences ion transport and interfacial stability of electrolytes,dictating battery cycle life and safety for solid-state lithium metal batteries.Despite promising properties of ethylene oxide-based electrolytes,their typical clamp-like coordination geometry leads to crowd solvation sheath and overly strong interactions between Li^(+)and electrolytes,rendering difficult dissociation of Li+and unfavorable solid electrolyte interface(SEI).Herein,we explore weakly solvating characteristics of polyacetal electrolytes owing to their alternately changing intervals between–O–coordinating sites in the main chain.Such structural asymmetry leads to unique distorted helical solvation sheath,and can effectively reduce Li^(+)-electrolyte binding and tune Li^(+)desolvation kinetics in the insitu formed polymer electrolytes,yielding anion-derived SEI and dendrite-free Li electrodeposition.Combining with photoinitiated cationic ring-opening polymerization,polyacetal electrolytes can be instantly formed within 5 min at the surface of electrode,with high segmental chain motion and well adapted interfaces.Such in-situ polyacetal electrolytes enabled more than 1300-h of stable lithium electrodeposition and prolonged cyclability over 200 cycles in solid-state batteries at ambient temperatures,demonstrating the vital role of molecular structure in changing solvating behavior and Li deposition stability for high-performance electrolytes.
文摘针对维间耦合会影响六维腕力传感器测量精度的问题,提出了基于多输出支持向量回归机(Multi-output support vector regression,MSVR)的解耦算法。以实验室研制的六维腕力传感器为例进行静态标定实验,使用基于MSVR的解耦算法以及传统的基于最小二乘求解标定矩阵的解耦算法对标定数据进行处理分析。实验结果表明,本文提出的解耦算法稳定可靠,能有效抑制维间耦合的干扰,具有较高的解耦精度。
基金financially supported by the National Natural Science Foundation of China(No.U2004177 and U21A2064)Outstanding Youth Fund of Henan Province(No.212300410081)+1 种基金Scientific and Technological Innovation Talents in Colleges and Universities in Henan Province(22HASTIT001)The Research and Entrepreneurship Start-up Projects for Overseas Returned Talents。
文摘Traditional ceramic materials are generally brittle and not flexible with high production costs,which seriously hinders their practical applications.Multifunctional nanofiber ceramic aerogels are highly desirable for applications in extreme environments,however,the integration of multiple functions in their preparation is extremely challenging.To tackle these challenges,we fabricated a multifunctional SiC@SiO_(2) nanofiber aerogel(SiC@SiO_(2) NFA)with a threedimensional(3D)porous cross-linked structure through a simple chemical vapor deposition method and subsequent heat-treatment process.The as-prepared SiC@SiO_(2) NFA exhibits an ultralow density(~11 mg cm^(-3)),ultra-elastic,fatigue-resistant and refractory performance,high temperature thermal stability,thermal insulation properties,and significant strain-dependent piezoresistive sensing behavior.Furthermore,the SiC@SiO_(2) NFA shows a superior electromagnetic wave absorption performance with a minimum refection loss(RL_(min))value of-50.36 d B and a maximum effective absorption bandwidth(EAB_(max))of 8.6 GHz.The successful preparation of this multifunctional aerogel material provides a promising prospect for the design and fabrication of the cutting-edge ceramic materials.
