The flow field of molten steel and the interfacial behaviour between molten steel and liquid slag layer in medium-thin slab continuous casting mold with argon gas injection were studied by numerical simulation, in whi...The flow field of molten steel and the interfacial behaviour between molten steel and liquid slag layer in medium-thin slab continuous casting mold with argon gas injection were studied by numerical simulation, in which the effects of nozzle submergence depth and port angle, casting speed, and argon gas flow rate on the flow and the level fluctuation of molten steel were considered. The results show that the molten steel is jetted from the submerged en- try nozzle （SEN） with three ports into the mold and forms three recirculation zones including one upper recireulation zone and two lower recirculation zones. Argon gas injection results in a secondary vortex flow in the upper zone near the nozzle. For a given casting speed and argon gas flow rate, increasing the side port angle and submergence depth of nozzle can effectively restrain the steel/slag interracial fluctuation. Increasing the casting speed would prick up the level fluctuation. For a fixed casting speed, argon gas flow rate has a critical value, the interracial fluctuation with argon gas injection are stronger than the case without argon gas injection when the argon gas flow rate is less than the critical value, but when the argon gas flow rate exceeds the critical value, the level fluctuation is calmer than that without argon gas injection.展开更多
目的探讨烧伤后期瘢痕整形儿复合植皮手术的美容效果。方法选择医院接诊的80例烧伤后期整形患儿作为研究对象,根据就诊顺序分为2组,单数为观察组,双数为对照组,各40例,均进行美容治疗,对照组使用自体中厚皮片移植治疗,观察组使用异体脱...目的探讨烧伤后期瘢痕整形儿复合植皮手术的美容效果。方法选择医院接诊的80例烧伤后期整形患儿作为研究对象,根据就诊顺序分为2组,单数为观察组,双数为对照组,各40例,均进行美容治疗,对照组使用自体中厚皮片移植治疗,观察组使用异体脱细胞真皮基质和自体中薄皮片移植治疗,术后均给予常规输液、止血、抗感染治疗。治疗3个月后,比较两组二次手术率、皮片成活率,以及两组OSAS瘢痕评价量表评分及瘢痕增生程度。结果观察组二次手术率明显低于对照组,成片成活率明显高于对照组(2.50%vs 22.50%,95.00%vs 72.50%)(P<0.05);观察组瘢痕颜色、平整度、弹性程度得分均明显优于对照组(0.47±0.07 vs 0.69±0.11,0.51±0.06 vs 0.78±0.10,0.42±0.05 vs 0.94±0.14)(P<0.05);观察组瘢痕重度增生发生率明显低于对照组(12.50%vs 42.50%(P<0.05)。结论烧伤后期瘢痕患儿使用异体脱细胞真皮基质复合自体中薄皮片的整形治疗效果显著,可有效修复瘢痕颜色、平整度、弹性程度,减轻瘢痕增生程度,恢复皮肤美观,美容效果优异。展开更多
利用VOF(volume of fluid)方法和Lagrangian离散模型模拟了厚度为135 mm中薄板坯连铸结晶器内的钢液流动及钢/渣界面波动行为,分析了结晶器宽度、水口浸入深度、水口侧孔倾角、拉速和吹氩对结晶器内钢液流动和液面波动的影响规律.结果表...利用VOF(volume of fluid)方法和Lagrangian离散模型模拟了厚度为135 mm中薄板坯连铸结晶器内的钢液流动及钢/渣界面波动行为,分析了结晶器宽度、水口浸入深度、水口侧孔倾角、拉速和吹氩对结晶器内钢液流动和液面波动的影响规律.结果表明:钢液从三孔浸入式水口流入结晶器后形成上、下三个回流区;吹氩使结晶器上回流区靠近水口附近形成二次涡流;在一定拉速下,增加水口侧孔倾角和浸入深度均能有效抑制钢/渣界面波动;增加拉速和在一定拉速下增加结晶器宽度均将加剧液面波动.展开更多
基金Item Sponsored by National Natural Science Foundation of China and Baosteel Co(50674020)
文摘The flow field of molten steel and the interfacial behaviour between molten steel and liquid slag layer in medium-thin slab continuous casting mold with argon gas injection were studied by numerical simulation, in which the effects of nozzle submergence depth and port angle, casting speed, and argon gas flow rate on the flow and the level fluctuation of molten steel were considered. The results show that the molten steel is jetted from the submerged en- try nozzle （SEN） with three ports into the mold and forms three recirculation zones including one upper recireulation zone and two lower recirculation zones. Argon gas injection results in a secondary vortex flow in the upper zone near the nozzle. For a given casting speed and argon gas flow rate, increasing the side port angle and submergence depth of nozzle can effectively restrain the steel/slag interracial fluctuation. Increasing the casting speed would prick up the level fluctuation. For a fixed casting speed, argon gas flow rate has a critical value, the interracial fluctuation with argon gas injection are stronger than the case without argon gas injection when the argon gas flow rate is less than the critical value, but when the argon gas flow rate exceeds the critical value, the level fluctuation is calmer than that without argon gas injection.
文摘目的探讨烧伤后期瘢痕整形儿复合植皮手术的美容效果。方法选择医院接诊的80例烧伤后期整形患儿作为研究对象,根据就诊顺序分为2组,单数为观察组,双数为对照组,各40例,均进行美容治疗,对照组使用自体中厚皮片移植治疗,观察组使用异体脱细胞真皮基质和自体中薄皮片移植治疗,术后均给予常规输液、止血、抗感染治疗。治疗3个月后,比较两组二次手术率、皮片成活率,以及两组OSAS瘢痕评价量表评分及瘢痕增生程度。结果观察组二次手术率明显低于对照组,成片成活率明显高于对照组(2.50%vs 22.50%,95.00%vs 72.50%)(P<0.05);观察组瘢痕颜色、平整度、弹性程度得分均明显优于对照组(0.47±0.07 vs 0.69±0.11,0.51±0.06 vs 0.78±0.10,0.42±0.05 vs 0.94±0.14)(P<0.05);观察组瘢痕重度增生发生率明显低于对照组(12.50%vs 42.50%(P<0.05)。结论烧伤后期瘢痕患儿使用异体脱细胞真皮基质复合自体中薄皮片的整形治疗效果显著,可有效修复瘢痕颜色、平整度、弹性程度,减轻瘢痕增生程度,恢复皮肤美观,美容效果优异。
文摘利用VOF(volume of fluid)方法和Lagrangian离散模型模拟了厚度为135 mm中薄板坯连铸结晶器内的钢液流动及钢/渣界面波动行为,分析了结晶器宽度、水口浸入深度、水口侧孔倾角、拉速和吹氩对结晶器内钢液流动和液面波动的影响规律.结果表明:钢液从三孔浸入式水口流入结晶器后形成上、下三个回流区;吹氩使结晶器上回流区靠近水口附近形成二次涡流;在一定拉速下,增加水口侧孔倾角和浸入深度均能有效抑制钢/渣界面波动;增加拉速和在一定拉速下增加结晶器宽度均将加剧液面波动.
