The influence of the preparation methods on the properties of SnO_2 and ZrO_2 powders,especially the specific surface area and the stability upon calcination was investigated.SnO_2 and ZrO_2 prepared by chemical preci...The influence of the preparation methods on the properties of SnO_2 and ZrO_2 powders,especially the specific surface area and the stability upon calcination was investigated.SnO_2 and ZrO_2 prepared by chemical precipitation using reflux-digestion process with NaOH possess high surface area at the calcination temperature of 500℃～1000℃.A novel solvothermal process in the presence of urea was used to synthesize nanocrystalline SnO_2 powders excluding the adulteration of Si.As increasing the concentration of urea,the grain size of the as-prepared powders reduced and the surface area increased. SnO_2 nanocrystals with a grain size of ca.1 nm and a high surface area of 331 m^2g^(-1) were obtained by this method.These high-surface-area powders are favorable for gas-sensing and catalysis applications,and the development of an advanced material for structural engineering ceramics.展开更多
目的:通过超声监测评估在妇科腹腔镜手术中应用Ⅰ-gel喉罩对患者胃内进气以及术后转归的影响。方法:选取全身麻醉下行妇科腹腔镜手术且手术时间不超过3 h的60例患者,年龄20~65岁,BMI<35 kg/m2,美国麻醉医师协会(American Society of ...目的:通过超声监测评估在妇科腹腔镜手术中应用Ⅰ-gel喉罩对患者胃内进气以及术后转归的影响。方法:选取全身麻醉下行妇科腹腔镜手术且手术时间不超过3 h的60例患者,年龄20~65岁,BMI<35 kg/m2,美国麻醉医师协会(American Society of Anesthesiologists,ASA)Ⅰ~Ⅱ级。根据手术中使用的通气工具将患者随机分为Ⅰ-gel喉罩组(Ⅰ组)和气管导管组(T组)。静脉推注咪达唑仑、舒芬太尼、依托咪酯、顺式阿曲库铵进行麻醉诱导,待意识消失后,容量控制下面罩通气120 s,按照分组分别插入喉罩或气管导管。记录基础值(T0)、插管/喉罩前(T1)、插管/喉罩时(T2)、手术结束(T3)、拔管/喉罩时(T4)的血流动力学参数(血压、心率),使用超声在麻醉诱导前(T5)、诱导后(T6)及手术结束(T7)时采集胃窦部横径、纵径计算其横截面积(cross sectional area,CSA)以及术后患者恶心、呕吐、咽痛、声嘶的发生率。结果:与Ⅰ组比较,T组在T2和T4时的SBP,DBP和HR均显著增加(P<0.05)。与T0时比较,两组SBP,DBP和HR均显著降低(P<0.05);与T1时比较,T组T2时SBP,DBP和HR明显增加(P<0.05);与T3时比较,T组T4时SBP,DBP和HR明显增加(P<0.05)。T组的胃窦CSA在手术结束时(T7)明显少于Ⅰ组(P<0.05)。与Ⅰ组比较,T组术后咽痛、声嘶的发生率明显增加(P<0.01)。结论:Ⅰ-gel喉罩的应用可能会导致少量气体进入胃内,但未引起返流误吸等严重并发症的发生,可以安全应用于妇科腹腔镜手术患者。展开更多
文摘The influence of the preparation methods on the properties of SnO_2 and ZrO_2 powders,especially the specific surface area and the stability upon calcination was investigated.SnO_2 and ZrO_2 prepared by chemical precipitation using reflux-digestion process with NaOH possess high surface area at the calcination temperature of 500℃～1000℃.A novel solvothermal process in the presence of urea was used to synthesize nanocrystalline SnO_2 powders excluding the adulteration of Si.As increasing the concentration of urea,the grain size of the as-prepared powders reduced and the surface area increased. SnO_2 nanocrystals with a grain size of ca.1 nm and a high surface area of 331 m^2g^(-1) were obtained by this method.These high-surface-area powders are favorable for gas-sensing and catalysis applications,and the development of an advanced material for structural engineering ceramics.
文摘目的:通过超声监测评估在妇科腹腔镜手术中应用Ⅰ-gel喉罩对患者胃内进气以及术后转归的影响。方法:选取全身麻醉下行妇科腹腔镜手术且手术时间不超过3 h的60例患者,年龄20~65岁,BMI<35 kg/m2,美国麻醉医师协会(American Society of Anesthesiologists,ASA)Ⅰ~Ⅱ级。根据手术中使用的通气工具将患者随机分为Ⅰ-gel喉罩组(Ⅰ组)和气管导管组(T组)。静脉推注咪达唑仑、舒芬太尼、依托咪酯、顺式阿曲库铵进行麻醉诱导,待意识消失后,容量控制下面罩通气120 s,按照分组分别插入喉罩或气管导管。记录基础值(T0)、插管/喉罩前(T1)、插管/喉罩时(T2)、手术结束(T3)、拔管/喉罩时(T4)的血流动力学参数(血压、心率),使用超声在麻醉诱导前(T5)、诱导后(T6)及手术结束(T7)时采集胃窦部横径、纵径计算其横截面积(cross sectional area,CSA)以及术后患者恶心、呕吐、咽痛、声嘶的发生率。结果:与Ⅰ组比较,T组在T2和T4时的SBP,DBP和HR均显著增加(P<0.05)。与T0时比较,两组SBP,DBP和HR均显著降低(P<0.05);与T1时比较,T组T2时SBP,DBP和HR明显增加(P<0.05);与T3时比较,T组T4时SBP,DBP和HR明显增加(P<0.05)。T组的胃窦CSA在手术结束时(T7)明显少于Ⅰ组(P<0.05)。与Ⅰ组比较,T组术后咽痛、声嘶的发生率明显增加(P<0.01)。结论:Ⅰ-gel喉罩的应用可能会导致少量气体进入胃内,但未引起返流误吸等严重并发症的发生,可以安全应用于妇科腹腔镜手术患者。
