The aim of this investigation was the determination of the predominant wear mechanism on three-body abrasion of fully pearlitic low alloy steel. Furthermore, the effect of pearlite interlamellar spacing on wear behavi...The aim of this investigation was the determination of the predominant wear mechanism on three-body abrasion of fully pearlitic low alloy steel. Furthermore, the effect of pearlite interlamellar spacing on wear behavior was investigated. For this purpose, the samples were subjected to the different heat treating to attaining different interlamellar spacing. Mechanical properties such as hardness, yield strength, tensile strength, elongation, and impact toughness were evaluated. Three body abrasion tests were conducted under ASTM standard condition using a rubber wheel abrasion test apparatus. Abraded surface and wear debris were investigated by light optical microscopy and scanning electron microscopy. The results showed that wear resistance of fully pearlitic steel depended to pearlite interlamellar spacing the and lower spacing has the greater wear resistance, so it may be due to subsurface work hardening and interlamellar spacing and cementite in fine and/or coarse pearlite, that influence on surface destruction during wear. Although during wear process the several mechanisms play roles, but study of surface and debris shows that with decreasing interlamellar spacing, the predominant mechanism wear changed from ploughing to cutting mode.展开更多
With the investigated subject of 82B rod, the interlamellar spacings of pearlite at different isothermal transformation temperatures and different cooling rates during continuous cooling transformation were measured, ...With the investigated subject of 82B rod, the interlamellar spacings of pearlite at different isothermal transformation temperatures and different cooling rates during continuous cooling transformation were measured, and the effect of the isothermal transformation temperature and cooling rate on the interlamellar spacing was analyzed quantitatively. Moreover, the relationship models between undercooling and interlamellar spacing were presented by data regression. The experimental results show that the relationship between undercooling and reciprocal interlamellar spacing remains linear when the undercooling is not very large, or else, the interlamellar spacing tends to be constant and the relationship will deviate from linearity.展开更多
目的:对比25G玻璃体切割联合人工晶状体经睫状沟巩膜缝线固定术和无缝线巩膜隧道层间固定术治疗晶状体完全脱位的疗效。方法:回顾性病例对照研究。选取2015-05/2021-09在我院确诊为晶状体完全脱位于玻璃体腔的患者40例40眼,其中行25G玻...目的:对比25G玻璃体切割联合人工晶状体经睫状沟巩膜缝线固定术和无缝线巩膜隧道层间固定术治疗晶状体完全脱位的疗效。方法:回顾性病例对照研究。选取2015-05/2021-09在我院确诊为晶状体完全脱位于玻璃体腔的患者40例40眼,其中行25G玻璃体切割联合人工晶状体经睫状沟巩膜缝线固定术者21眼(缝线组),行25G玻璃体切割联合人工晶状体无缝线巩膜隧道层间固定术者19眼(无缝线组)。随访至术后3mo,观察两组患者手术时间、最佳矫正视力(BCVA)、角膜内皮细胞计数(CECC)、中央角膜厚度(CCT)及术后并发症情况。结果:无缝线组手术用时显著短于缝线组(31.79±6.01min vs 45.38±8.04min,P<0.001)。两组患者术后BCVA均较术前显著改善(均P<0.05),术后1wk无缝线组BCVA(LogMAR)显著优于缝线组(0.32±0.14 vs 0.57±0.25,P<0.001)。术后3mo,两组患者CECC均低于术前(均P<0.01)。缝线组术后1wk CCT大于术前和术后3mo(均P<0.01),无缝线组手术前后CCT无显著变化。随访期间,无缝线组并发症总发生率低于缝线组(26%vs 38%,P>0.05)。结论:25G玻璃体切割联合人工晶状体无缝线巩膜隧道层间固定术治疗晶状体完全脱位手术时间短,术后视力提升快,术后并发症少。展开更多
标准YB/T169-2000规定,通过光学显微镜中明暗差异测量高碳钢组织的索氏体含量。为了分析光学显微镜中各明暗区域对应的组织结构,对铅浴退火抗拉强度为1 296 MPa的Φ0.9 mm 82A高碳钢丝试样采用显微硬度计做定点标记,使用光学显微镜和扫...标准YB/T169-2000规定,通过光学显微镜中明暗差异测量高碳钢组织的索氏体含量。为了分析光学显微镜中各明暗区域对应的组织结构,对铅浴退火抗拉强度为1 296 MPa的Φ0.9 mm 82A高碳钢丝试样采用显微硬度计做定点标记,使用光学显微镜和扫描电子显微镜进行观察,同时通过不同浸蚀方式分析明暗区域出现的原因。结果证实白亮区域和类似珠光体片层组织均为索氏体组织。局部深腐蚀导致片层假象,而白亮区域和类似珠光体出现均与垂直于拉拔方向索氏体团相关。展开更多
文摘The aim of this investigation was the determination of the predominant wear mechanism on three-body abrasion of fully pearlitic low alloy steel. Furthermore, the effect of pearlite interlamellar spacing on wear behavior was investigated. For this purpose, the samples were subjected to the different heat treating to attaining different interlamellar spacing. Mechanical properties such as hardness, yield strength, tensile strength, elongation, and impact toughness were evaluated. Three body abrasion tests were conducted under ASTM standard condition using a rubber wheel abrasion test apparatus. Abraded surface and wear debris were investigated by light optical microscopy and scanning electron microscopy. The results showed that wear resistance of fully pearlitic steel depended to pearlite interlamellar spacing the and lower spacing has the greater wear resistance, so it may be due to subsurface work hardening and interlamellar spacing and cementite in fine and/or coarse pearlite, that influence on surface destruction during wear. Although during wear process the several mechanisms play roles, but study of surface and debris shows that with decreasing interlamellar spacing, the predominant mechanism wear changed from ploughing to cutting mode.
文摘With the investigated subject of 82B rod, the interlamellar spacings of pearlite at different isothermal transformation temperatures and different cooling rates during continuous cooling transformation were measured, and the effect of the isothermal transformation temperature and cooling rate on the interlamellar spacing was analyzed quantitatively. Moreover, the relationship models between undercooling and interlamellar spacing were presented by data regression. The experimental results show that the relationship between undercooling and reciprocal interlamellar spacing remains linear when the undercooling is not very large, or else, the interlamellar spacing tends to be constant and the relationship will deviate from linearity.
文摘目的:对比25G玻璃体切割联合人工晶状体经睫状沟巩膜缝线固定术和无缝线巩膜隧道层间固定术治疗晶状体完全脱位的疗效。方法:回顾性病例对照研究。选取2015-05/2021-09在我院确诊为晶状体完全脱位于玻璃体腔的患者40例40眼,其中行25G玻璃体切割联合人工晶状体经睫状沟巩膜缝线固定术者21眼(缝线组),行25G玻璃体切割联合人工晶状体无缝线巩膜隧道层间固定术者19眼(无缝线组)。随访至术后3mo,观察两组患者手术时间、最佳矫正视力(BCVA)、角膜内皮细胞计数(CECC)、中央角膜厚度(CCT)及术后并发症情况。结果:无缝线组手术用时显著短于缝线组(31.79±6.01min vs 45.38±8.04min,P<0.001)。两组患者术后BCVA均较术前显著改善(均P<0.05),术后1wk无缝线组BCVA(LogMAR)显著优于缝线组(0.32±0.14 vs 0.57±0.25,P<0.001)。术后3mo,两组患者CECC均低于术前(均P<0.01)。缝线组术后1wk CCT大于术前和术后3mo(均P<0.01),无缝线组手术前后CCT无显著变化。随访期间,无缝线组并发症总发生率低于缝线组(26%vs 38%,P>0.05)。结论:25G玻璃体切割联合人工晶状体无缝线巩膜隧道层间固定术治疗晶状体完全脱位手术时间短,术后视力提升快,术后并发症少。
文摘标准YB/T169-2000规定,通过光学显微镜中明暗差异测量高碳钢组织的索氏体含量。为了分析光学显微镜中各明暗区域对应的组织结构,对铅浴退火抗拉强度为1 296 MPa的Φ0.9 mm 82A高碳钢丝试样采用显微硬度计做定点标记,使用光学显微镜和扫描电子显微镜进行观察,同时通过不同浸蚀方式分析明暗区域出现的原因。结果证实白亮区域和类似珠光体片层组织均为索氏体组织。局部深腐蚀导致片层假象,而白亮区域和类似珠光体出现均与垂直于拉拔方向索氏体团相关。
