The effect of depressurizing speed on mold filling behavior and entrainment of oxide film of A356 alloy was studied. Themold filling behavior and velocity fields were recorded by water simulation with particle image v...The effect of depressurizing speed on mold filling behavior and entrainment of oxide film of A356 alloy was studied. Themold filling behavior and velocity fields were recorded by water simulation with particle image velocimetry. The results show thatthe gate velocity first increased dramatically, then changed with the depressurizing speed: the gate velocity increased slowly atrelatively high depressurizing speed; at reasonable depressurizing speed, the gate velocity kept unchanged; while at lowerdepressurizing speed, the gate velocity decreased firstly and then kept unchanged. High gate velocity results in melt falling backunder gravity at higher speed. The falling velocity is the main factor of oxide film entrainment in vacuum suction casting. The designcriterion of depressurizing rate was deduced, and the A356 alloy castings were poured to test the formula. The four-point bend testand Weibull probability plots were applied to assessing the fracture mechanisms of the as-cast A356 alloy. The results illuminate amethod on designing suitable depressurizing speed for mold filling in vacuum suction casting.展开更多
目的探讨Kiwi胎头真空吸引器在阴道助产分娩中的应用价值。方法选取2020年7月至2023年3月于扬州大学临床医学院使用Kiwi胎头真空吸引器实施胎头吸引的初产孕妇30例为胎吸组,同时选取计划阴道分娩而后因特殊原因行剖宫产终止妊娠的孕妇2...目的探讨Kiwi胎头真空吸引器在阴道助产分娩中的应用价值。方法选取2020年7月至2023年3月于扬州大学临床医学院使用Kiwi胎头真空吸引器实施胎头吸引的初产孕妇30例为胎吸组,同时选取计划阴道分娩而后因特殊原因行剖宫产终止妊娠的孕妇23例为剖宫产组。比较2组术中及术后情况及新生儿相关指标。结果2组第二产程时间、产时出血量、产后24 h出血量、产后住院时间及软产道损伤、产后会阴水肿发生情况比较,差异无统计学意义(P>0.05)。2组产后尿潴留发生率比较,差异有统计学意义(P<0.05)。2组新生儿出生体重及头皮血肿、颅内出血发生情况比较,差异无统计学意义(P>0.05)。胎吸组新生儿中,3例娩出后1 min Apgar评分分别为8、9、6分。剖宫产组新生儿中,仅1例娩出后1 min Apgar评分为7分。胎吸组新生儿中,有9例(30.00%)因黄疸、呼吸急促、窒息等原因转至新生儿科;剖宫产组新生儿中,有4例(17.39%)因黄疸、新生儿低血糖、鼻塞等原因转至新生儿科。胎吸组转科新生儿中,2例(15.38%)出现高总胆红素血症,剖宫产组未出现高总胆红素血症。胎吸组、剖宫产组新生儿动脉血pH值分别为(7.38±0.02)、(7.45±0.02),二者比较差异有统计学意义(P<0.05)。结论Kiwi胎头真空吸引器操作简便,适用范围广,其应用于阴道助产中有效缩短产程,降低剖宫产率、产妇及新生儿相关并发症发生率。展开更多
目的探讨自制测压吸石输尿管扩张鞘联合负压吸引器在输尿管软镜治疗肾结石术中的应用价值。方法2015年3~5月,使用自制测压吸石输尿管扩张鞘(专利号:201520062247.6)配合负压吸引装置,对33例肾结石行输尿管软镜钬激光碎石治疗。术前设定...目的探讨自制测压吸石输尿管扩张鞘联合负压吸引器在输尿管软镜治疗肾结石术中的应用价值。方法2015年3~5月,使用自制测压吸石输尿管扩张鞘(专利号:201520062247.6)配合负压吸引装置,对33例肾结石行输尿管软镜钬激光碎石治疗。术前设定灌注泵流量0.2 L/min,灌注压力上限设定为100 mm Hg,吸引负压为10 k Pa,通过自制测压吸石输尿管扩张鞘副通道监测肾内压力,使用蚕食法边碎石边吸石,尽量将结石击碎至0.2 mm,术中根据视野清晰情况及肾内压力大小对灌注流量、压力及时进行调整。结果术中初始肾内压力为(14.7±3.2)mm Hg(9~22 mm Hg),灌注时间(29.3±2.5)min(25~37 min),术中视野清晰,无肾脏出血、破裂,术后生命体征平稳,无发热、尿源性脓毒血症等并发症,出院前1天复查腹部平片提示残留结石最大直径约1 cm 9例,0.5 cm 15例,<0.3 cm 9例,术后住院时间均为2天。术后1个月均返院取出双J管。术后2个月复查腹部平片及泌尿系B超,28例未见结石残留,5例见结石碎片残留于肾下极,直径<0.3 cm。结论本研究初步表明,使用自制测压吸石输尿管扩张鞘,手术过程安全,正负压力、进出流量可控,吸石效果良好。展开更多
基金Project(51375110)supported by the National Natural Science Foundation of Chain
文摘The effect of depressurizing speed on mold filling behavior and entrainment of oxide film of A356 alloy was studied. Themold filling behavior and velocity fields were recorded by water simulation with particle image velocimetry. The results show thatthe gate velocity first increased dramatically, then changed with the depressurizing speed: the gate velocity increased slowly atrelatively high depressurizing speed; at reasonable depressurizing speed, the gate velocity kept unchanged; while at lowerdepressurizing speed, the gate velocity decreased firstly and then kept unchanged. High gate velocity results in melt falling backunder gravity at higher speed. The falling velocity is the main factor of oxide film entrainment in vacuum suction casting. The designcriterion of depressurizing rate was deduced, and the A356 alloy castings were poured to test the formula. The four-point bend testand Weibull probability plots were applied to assessing the fracture mechanisms of the as-cast A356 alloy. The results illuminate amethod on designing suitable depressurizing speed for mold filling in vacuum suction casting.
文摘目的探讨Kiwi胎头真空吸引器在阴道助产分娩中的应用价值。方法选取2020年7月至2023年3月于扬州大学临床医学院使用Kiwi胎头真空吸引器实施胎头吸引的初产孕妇30例为胎吸组,同时选取计划阴道分娩而后因特殊原因行剖宫产终止妊娠的孕妇23例为剖宫产组。比较2组术中及术后情况及新生儿相关指标。结果2组第二产程时间、产时出血量、产后24 h出血量、产后住院时间及软产道损伤、产后会阴水肿发生情况比较,差异无统计学意义(P>0.05)。2组产后尿潴留发生率比较,差异有统计学意义(P<0.05)。2组新生儿出生体重及头皮血肿、颅内出血发生情况比较,差异无统计学意义(P>0.05)。胎吸组新生儿中,3例娩出后1 min Apgar评分分别为8、9、6分。剖宫产组新生儿中,仅1例娩出后1 min Apgar评分为7分。胎吸组新生儿中,有9例(30.00%)因黄疸、呼吸急促、窒息等原因转至新生儿科;剖宫产组新生儿中,有4例(17.39%)因黄疸、新生儿低血糖、鼻塞等原因转至新生儿科。胎吸组转科新生儿中,2例(15.38%)出现高总胆红素血症,剖宫产组未出现高总胆红素血症。胎吸组、剖宫产组新生儿动脉血pH值分别为(7.38±0.02)、(7.45±0.02),二者比较差异有统计学意义(P<0.05)。结论Kiwi胎头真空吸引器操作简便,适用范围广,其应用于阴道助产中有效缩短产程,降低剖宫产率、产妇及新生儿相关并发症发生率。
文摘目的探讨自制测压吸石输尿管扩张鞘联合负压吸引器在输尿管软镜治疗肾结石术中的应用价值。方法2015年3~5月,使用自制测压吸石输尿管扩张鞘(专利号:201520062247.6)配合负压吸引装置,对33例肾结石行输尿管软镜钬激光碎石治疗。术前设定灌注泵流量0.2 L/min,灌注压力上限设定为100 mm Hg,吸引负压为10 k Pa,通过自制测压吸石输尿管扩张鞘副通道监测肾内压力,使用蚕食法边碎石边吸石,尽量将结石击碎至0.2 mm,术中根据视野清晰情况及肾内压力大小对灌注流量、压力及时进行调整。结果术中初始肾内压力为(14.7±3.2)mm Hg(9~22 mm Hg),灌注时间(29.3±2.5)min(25~37 min),术中视野清晰,无肾脏出血、破裂,术后生命体征平稳,无发热、尿源性脓毒血症等并发症,出院前1天复查腹部平片提示残留结石最大直径约1 cm 9例,0.5 cm 15例,<0.3 cm 9例,术后住院时间均为2天。术后1个月均返院取出双J管。术后2个月复查腹部平片及泌尿系B超,28例未见结石残留,5例见结石碎片残留于肾下极,直径<0.3 cm。结论本研究初步表明,使用自制测压吸石输尿管扩张鞘,手术过程安全,正负压力、进出流量可控,吸石效果良好。
