The impact-abrasive wear behavior of high-C martensitic steel was investigated,taking into account varying carbon(C)contents and different tempering temperatures.The evaluation was done through comprehensive microstru...The impact-abrasive wear behavior of high-C martensitic steel was investigated,taking into account varying carbon(C)contents and different tempering temperatures.The evaluation was done through comprehensive microstructural characterization,analysis of worn surface morphology,and measurement of key performance like impact toughness and surface hardening.The findings demonstrate that increasing C content and tempering temperature both has a positive effect on wear resistance,with C content exhibiting a more pronounced influence compared to the tempering temperature.The improved wear resistance of the steel with higher C content and tempering at a higher temperature can be attributed to its enhanced impact toughness.This increase in impact toughness is primarily a result of microstructural refinement and alterations in carbide morphology.Moreover,cyclic impact loading induces surface hardening due to dislocation strengthening within the martensite and the retained austenite,leading to an increase in surface hardness.The combination of surface hardening and excellent impact toughness synergistically contributes to the overall improved wear resistance observed in the experimental steel with higher C content after tempering at a higher temperature.Additionally,the dominant features observed on the worn surface are scratches and substrate delamination,indicative of a wear mechanism of the experimental steels characterized by micro-cutting/ploughing and fatigue wear.展开更多
Elemental analyzer/isotope ratio mass spectrometry(EA/TRMS) has been widely applied to analyze the^(15)N/^(14)N isotope composition(δ^(15)N) of plants and soils,but the δ^(15)N results may be inaccurate due to incom...Elemental analyzer/isotope ratio mass spectrometry(EA/TRMS) has been widely applied to analyze the^(15)N/^(14)N isotope composition(δ^(15)N) of plants and soils,but the δ^(15)N results may be inaccurate due to incomplete combustion of the high-C/N-ratio plant samples by EA.Therefore,it is necessary to develop a method to solve the problem of imperfect combustion.In this study,we used two methods:1) adding copper oxide powder to the samples,and 2) increasing the O_2 flow(from 100 mL min^(-1) to 200 mL min^(-1)) for the auto sampler inlet purge line of the EA.The δ^(15)N values of the plant samples became more positive and tended to be stable after complete combustion.Also,the required blank samples for each plant sample decreased with increasing amount of the added CuO powder.However,at 200 mL min^(-1) of the oxygen flow in the EA,complete combustion could not be achieved without adding copper oxide,but this was done with decreased amount of CuO powder.Therefore,mixing cupric oxide into the high-C/N-ratio samples was an efficient,simple and convenient way to solve the problem of imperfect combustion in the EA.展开更多
目的系统评价秋水仙碱对冠状动脉粥样硬化性心脏病患者超敏C反应蛋白(hs-CRP)与其他炎症标志物水平的影响。方法计算机检索PubMed、Embase、Web of Science、Cochrane Library、ClinicalTrials.gov、CNKI、WanFang Data和VIP数据库,搜...目的系统评价秋水仙碱对冠状动脉粥样硬化性心脏病患者超敏C反应蛋白(hs-CRP)与其他炎症标志物水平的影响。方法计算机检索PubMed、Embase、Web of Science、Cochrane Library、ClinicalTrials.gov、CNKI、WanFang Data和VIP数据库,搜集与研究目的相关的随机对照试验(RCT),检索时限均从建库至2025年6月13日,由2名研究者独立筛选文献、提取资料并评价纳入研究的偏倚风险后,采用RevMan 5.3软件进行Meta分析。结果共纳入12个RCT,包括6351例患者。Meta分析结果显示,与安慰剂相比,秋水仙碱治疗能降低hs-CRP水平[MD=-0.73,95%CI(-0.89,-0.56),P<0.001]和主要不良心血管事件(MACE)发生率[RR=0.76,95%CI(0.63,0.91),P=0.003],但秋水仙碱组与安慰剂组患者的白细胞计数变化值、中性粒细胞计数变化值、白细胞介素-1β水平、白介素-6水平差异无统计学意义(P>0.05)。结论秋水仙碱治疗冠状动脉粥样硬化性心脏病患者能降低hs-CRP水平和MACE发生风险。受纳入研究数量和质量的限制,上述结论尚需开展更多高质量的研究予以验证。展开更多
目的研究尘肺病患者膳食炎症指数与临床症状及炎症指标的相关性。方法随机选取2024年1月—2025年12月于某院就诊的120例职业性尘肺病患者,经食物频率调查问卷获取研究对象的饮食数据,通过中国食物成分表(2023版)分别计算各种膳食成分含...目的研究尘肺病患者膳食炎症指数与临床症状及炎症指标的相关性。方法随机选取2024年1月—2025年12月于某院就诊的120例职业性尘肺病患者,经食物频率调查问卷获取研究对象的饮食数据,通过中国食物成分表(2023版)分别计算各种膳食成分含量,从而获得个人膳食炎症指数评分,根据膳食炎症指数评分(dietary inflammatory index,DII)水平进行四分位分组,分别为Q1组(DII≤-0.48)、Q2组(-0.48<DII≤0.44)、Q3组(0.440.81)。研究对象均完成完善慢阻肺病患者评估测试评分(chronic obstructive pulmonary test,CAT)、改良版英国研究委员会呼吸困难问卷评分(modified medical research council dyspnea scale,mMRC)、六分钟步行测试(six minutes walk test,6MWT)等评价呼吸系统临床症状的相关指标及血清C反应蛋白等炎症指标。结果根据DII评分水平进行四分位分组,可见与白细胞计数、中性粒细胞、超敏C反应蛋白、CAT评分、mMRC评分呈正相关,与6MWT呈负相关,差异均有统计学意义(F=4.297、3.031、3.657、79.245、5.278、3.668,P<0.05)。组间在年龄、工龄、嗜酸性粒细胞水平比较,差异无统计学意义(F=0.954、2.369、0.725,P>0.05)。相关分析显示,DII作为连续变量,与炎症指标白细胞计数(r=0.294,P<0.01)、中性粒细胞(r=0.201,P=0.028)、超敏C反应蛋白(r=0.283,P<0.01)具有相关性,而与嗜酸性粒细胞无相关性(r=-0.055,P=0.547),多元线性回归分析进一步显示,DII评分与CAT评分(B=6.23,β=0.71,t=12.081,95%CI:5.21~7.25)和mMRC评分(B=0.33,β=0.09,t=3.897,95%CI:0.16~0.50)呈正相关联,差异有统计学意义(P<0.05),DII评分与6MWT(B=-22.91,β=-0.25,t=-2.575,95%CI:-40.54~-5.28)呈负相关联,差异有统计学意义(P<0.05)。结论促炎饮食会影响尘肺患者肺功能,向尘肺患者普及不同膳食与炎症相关知识非常必要。展开更多
基金supported by Science and Technology Project of Guangzhou(2023A04J0297)Guangdong Basic and Applied Basic Research Foundation(2024A1515011622)+3 种基金National Natural Science Foundation of China(52301040)GDAS’Project of Science and Technology Development(2023GDASQNRC-0205 and 2022GDASZH-2022010107)Evaluation Project of Guangdong Provincial Key Laboratory(2023B1212060043)Young Elite Scientists Sponsorship Program by CAST(2022QNRC001).
文摘The impact-abrasive wear behavior of high-C martensitic steel was investigated,taking into account varying carbon(C)contents and different tempering temperatures.The evaluation was done through comprehensive microstructural characterization,analysis of worn surface morphology,and measurement of key performance like impact toughness and surface hardening.The findings demonstrate that increasing C content and tempering temperature both has a positive effect on wear resistance,with C content exhibiting a more pronounced influence compared to the tempering temperature.The improved wear resistance of the steel with higher C content and tempering at a higher temperature can be attributed to its enhanced impact toughness.This increase in impact toughness is primarily a result of microstructural refinement and alterations in carbide morphology.Moreover,cyclic impact loading induces surface hardening due to dislocation strengthening within the martensite and the retained austenite,leading to an increase in surface hardness.The combination of surface hardening and excellent impact toughness synergistically contributes to the overall improved wear resistance observed in the experimental steel with higher C content after tempering at a higher temperature.Additionally,the dominant features observed on the worn surface are scratches and substrate delamination,indicative of a wear mechanism of the experimental steels characterized by micro-cutting/ploughing and fatigue wear.
文摘Elemental analyzer/isotope ratio mass spectrometry(EA/TRMS) has been widely applied to analyze the^(15)N/^(14)N isotope composition(δ^(15)N) of plants and soils,but the δ^(15)N results may be inaccurate due to incomplete combustion of the high-C/N-ratio plant samples by EA.Therefore,it is necessary to develop a method to solve the problem of imperfect combustion.In this study,we used two methods:1) adding copper oxide powder to the samples,and 2) increasing the O_2 flow(from 100 mL min^(-1) to 200 mL min^(-1)) for the auto sampler inlet purge line of the EA.The δ^(15)N values of the plant samples became more positive and tended to be stable after complete combustion.Also,the required blank samples for each plant sample decreased with increasing amount of the added CuO powder.However,at 200 mL min^(-1) of the oxygen flow in the EA,complete combustion could not be achieved without adding copper oxide,but this was done with decreased amount of CuO powder.Therefore,mixing cupric oxide into the high-C/N-ratio samples was an efficient,simple and convenient way to solve the problem of imperfect combustion in the EA.
文摘目的研究尘肺病患者膳食炎症指数与临床症状及炎症指标的相关性。方法随机选取2024年1月—2025年12月于某院就诊的120例职业性尘肺病患者,经食物频率调查问卷获取研究对象的饮食数据,通过中国食物成分表(2023版)分别计算各种膳食成分含量,从而获得个人膳食炎症指数评分,根据膳食炎症指数评分(dietary inflammatory index,DII)水平进行四分位分组,分别为Q1组(DII≤-0.48)、Q2组(-0.48<DII≤0.44)、Q3组(0.440.81)。研究对象均完成完善慢阻肺病患者评估测试评分(chronic obstructive pulmonary test,CAT)、改良版英国研究委员会呼吸困难问卷评分(modified medical research council dyspnea scale,mMRC)、六分钟步行测试(six minutes walk test,6MWT)等评价呼吸系统临床症状的相关指标及血清C反应蛋白等炎症指标。结果根据DII评分水平进行四分位分组,可见与白细胞计数、中性粒细胞、超敏C反应蛋白、CAT评分、mMRC评分呈正相关,与6MWT呈负相关,差异均有统计学意义(F=4.297、3.031、3.657、79.245、5.278、3.668,P<0.05)。组间在年龄、工龄、嗜酸性粒细胞水平比较,差异无统计学意义(F=0.954、2.369、0.725,P>0.05)。相关分析显示,DII作为连续变量,与炎症指标白细胞计数(r=0.294,P<0.01)、中性粒细胞(r=0.201,P=0.028)、超敏C反应蛋白(r=0.283,P<0.01)具有相关性,而与嗜酸性粒细胞无相关性(r=-0.055,P=0.547),多元线性回归分析进一步显示,DII评分与CAT评分(B=6.23,β=0.71,t=12.081,95%CI:5.21~7.25)和mMRC评分(B=0.33,β=0.09,t=3.897,95%CI:0.16~0.50)呈正相关联,差异有统计学意义(P<0.05),DII评分与6MWT(B=-22.91,β=-0.25,t=-2.575,95%CI:-40.54~-5.28)呈负相关联,差异有统计学意义(P<0.05)。结论促炎饮食会影响尘肺患者肺功能,向尘肺患者普及不同膳食与炎症相关知识非常必要。
