目的分析采用耳内镜下鼓膜置管并CBCT(Cone beam CT,即锥形束CT)术前术后评估小儿分泌性中耳炎25例的疗效。方法采用CBCT术前评估分泌性中耳炎25例,男11例,女14例,双耳20例,单耳5例,平均年龄5.52岁,单纯行耳内镜下鼓膜切开置管2例(4耳)...目的分析采用耳内镜下鼓膜置管并CBCT(Cone beam CT,即锥形束CT)术前术后评估小儿分泌性中耳炎25例的疗效。方法采用CBCT术前评估分泌性中耳炎25例,男11例,女14例,双耳20例,单耳5例,平均年龄5.52岁,单纯行耳内镜下鼓膜切开置管2例(4耳),腺样体切除术后3月以上行耳内镜下鼓膜切开置管7例(9耳,单纯鼓膜切开1耳),腺样体等离子消融术同期耳内镜下鼓膜切开置管16例(30耳,单纯鼓膜切开1耳)。结果术后3月复查CBCT:乳突蜂房发育良好,未见积液及软组织充满乳突24例拔管,1例双耳脱管后复发再次置管并球囊扩张,半年后脱管再次置管中,复查纯音测听0.5、1.0、2.0 k Hz气骨导差15 d B,1例拔管3月后再次鼓室积液再次置管并球囊扩张未找到咽鼓管咽口3月后脱管未再手术。其余23例纯音测听均回复正常,2例出现鼓室负压,声阻抗C型曲线,咽鼓管吹张1月后恢复致A型曲线。结论CBCT因辐射小,又可实现中耳薄扫,评估分泌性中耳炎术前术后情况更精准有效。耳内镜下鼓膜置管术治疗儿童分泌性中耳炎安全有效,不仅提高患儿的听力,还能缩短中耳积液时间,降低复发率及感染的发生率,值得推广应用,腺样体切除同时应评估是否需要鼓膜切开置管,避免二次手术。展开更多
Ignition timing control is of great importance in homogeneous charge compression ignition engines. The effect of hydrogen addition on methane combustion was investigated using a CHEMKIN multi-zone model. Results show ...Ignition timing control is of great importance in homogeneous charge compression ignition engines. The effect of hydrogen addition on methane combustion was investigated using a CHEMKIN multi-zone model. Results show that hydrogen addition advances ignition tim- ing and enhances peak pressure and temperature. A brief analysis of chemical kinetics of methane blending hydrogen is also performed in order to investigate the scope of its appli- cation, and the analysis suggests that OH radical plays an important role in the oxidation. Hydrogen addition increases NOx while decreasing HC and CO emissions. Exhaust gas recir- culation （EGR） also advances ignition timing; however, its effects on emissions are generally the opposite. By adjusting the hydrogen addition and EGR rate, the ignition timing can be regulated with a low emission level. Investigation into zones suggests that NOx is mostly formed in core zones while HC and CO mostly originate in the crevice and the quench layer.展开更多
目的:研究深慢波睡眠剥夺对大鼠睾丸组织氧化应激反应的影响。方法:36只5周龄健康雄性Wistar大鼠,随机分为深慢波睡眠时相剥夺组(SD1组)、深慢波睡眠时相及时长剥夺组(SD2组)和空白对照组(CC组),每组12只,利用小平台水环境建立深慢波睡...目的:研究深慢波睡眠剥夺对大鼠睾丸组织氧化应激反应的影响。方法:36只5周龄健康雄性Wistar大鼠,随机分为深慢波睡眠时相剥夺组(SD1组)、深慢波睡眠时相及时长剥夺组(SD2组)和空白对照组(CC组),每组12只,利用小平台水环境建立深慢波睡眠剥夺模型。SD1组每间隔24 min干扰1次,SD2组每间隔24min剥夺睡眠8 min;夜间都进行12 h的完全睡眠剥夺。CC组模拟正常的12 h光照、12 h黑暗时间。28 d后,大鼠股动脉放血,留取睾丸组织进行称重,测定睾丸组织中蛋白含量、丙二醛(MDA)、谷胱甘肽过氧化物酶(GSH-Px)、超氧化物岐化酶(SOD)水平,显微镜下观察睾丸病理结构的改变。结果:SD1、SD2组大鼠的终末体质量[(248.1±25.1)g、(232.9±10.1)g]均下降,与CC组[(268.5±1.6)g]相比差异有统计学意义(P均<0.05);与CC组相比,SD2组睾丸相对质量明显升高[(54.9±3.5)×10^(-2)vs(50.0±1.3)×10^(-2),P<0.05]。与CC组相比,SD2组睾丸组织蛋白含量、MDA含量、SOD活性和GSH-Px均有显著差异[蛋白含量:(4.5±0.9)g pro/L vs 6.3±1.4)g pro/L;MDA含量:(1.3±0.3)nmol/mg pro vs(1.1±0.1)nmol/mg pro;SOD活性:(135.2±26.9)U/mg pro vs(104.3±33.1)U/mg pro;GSH-Px活性:(21.7±4.3)U/mg pro vs(15.6±4.0)U/mg pro,P均<0.05],而与SD1组比较差异无统计学意义。SD1组睾丸病理学改变不明显,但SD2组睾丸生精小管管腔变小,周围间质部分增加,间质充血水肿明显。结论:长期深慢波睡眠剥夺对大鼠睾丸组织结构产生损伤并引起氧化应激反应。展开更多
文摘目的分析采用耳内镜下鼓膜置管并CBCT(Cone beam CT,即锥形束CT)术前术后评估小儿分泌性中耳炎25例的疗效。方法采用CBCT术前评估分泌性中耳炎25例,男11例,女14例,双耳20例,单耳5例,平均年龄5.52岁,单纯行耳内镜下鼓膜切开置管2例(4耳),腺样体切除术后3月以上行耳内镜下鼓膜切开置管7例(9耳,单纯鼓膜切开1耳),腺样体等离子消融术同期耳内镜下鼓膜切开置管16例(30耳,单纯鼓膜切开1耳)。结果术后3月复查CBCT:乳突蜂房发育良好,未见积液及软组织充满乳突24例拔管,1例双耳脱管后复发再次置管并球囊扩张,半年后脱管再次置管中,复查纯音测听0.5、1.0、2.0 k Hz气骨导差15 d B,1例拔管3月后再次鼓室积液再次置管并球囊扩张未找到咽鼓管咽口3月后脱管未再手术。其余23例纯音测听均回复正常,2例出现鼓室负压,声阻抗C型曲线,咽鼓管吹张1月后恢复致A型曲线。结论CBCT因辐射小,又可实现中耳薄扫,评估分泌性中耳炎术前术后情况更精准有效。耳内镜下鼓膜置管术治疗儿童分泌性中耳炎安全有效,不仅提高患儿的听力,还能缩短中耳积液时间,降低复发率及感染的发生率,值得推广应用,腺样体切除同时应评估是否需要鼓膜切开置管,避免二次手术。
文摘为提高星载电子器件热分析的模拟分辨率和精度以及被动热控装置的控温效果,本文建立系统多尺度模型获得不同尺度下卫星内部电子器件的温度场和热流信息.结果表明:系统多尺度模型在系统级尺度模拟精度与实际模型相对误差小于9%,并且可消耗较少的计算资源获得器件级尺度芯片微小结构的热信息.系统级模型可从宏观尺度评估星载被动热控材料的控温隔热性能,采用复合相变隔热材料可将载荷舱室温度波动幅值降至2.43 K,相比平台舱室温度波动幅值降低约69.43%,通过复合相变隔热材料隔热后的温度波动信号呈现向高频域部分转移的特征.基于多元回归分析选定需要进行重点隔热控温的舱室后,采用器件级简化模型得到不同热控装置布局下的温度场信息形成训练数据集,采用神经网络遗传算法在器件尺度预测被动热控装置的最佳安装位置,并得到减小器件最大温度波动的热控布局方案,最大温度波动降低2.74 K.
基金This work was supported by the Natural Science Foundation of Anhui Province （No.090412030）.
文摘Ignition timing control is of great importance in homogeneous charge compression ignition engines. The effect of hydrogen addition on methane combustion was investigated using a CHEMKIN multi-zone model. Results show that hydrogen addition advances ignition tim- ing and enhances peak pressure and temperature. A brief analysis of chemical kinetics of methane blending hydrogen is also performed in order to investigate the scope of its appli- cation, and the analysis suggests that OH radical plays an important role in the oxidation. Hydrogen addition increases NOx while decreasing HC and CO emissions. Exhaust gas recir- culation （EGR） also advances ignition timing; however, its effects on emissions are generally the opposite. By adjusting the hydrogen addition and EGR rate, the ignition timing can be regulated with a low emission level. Investigation into zones suggests that NOx is mostly formed in core zones while HC and CO mostly originate in the crevice and the quench layer.
文摘目的:研究深慢波睡眠剥夺对大鼠睾丸组织氧化应激反应的影响。方法:36只5周龄健康雄性Wistar大鼠,随机分为深慢波睡眠时相剥夺组(SD1组)、深慢波睡眠时相及时长剥夺组(SD2组)和空白对照组(CC组),每组12只,利用小平台水环境建立深慢波睡眠剥夺模型。SD1组每间隔24 min干扰1次,SD2组每间隔24min剥夺睡眠8 min;夜间都进行12 h的完全睡眠剥夺。CC组模拟正常的12 h光照、12 h黑暗时间。28 d后,大鼠股动脉放血,留取睾丸组织进行称重,测定睾丸组织中蛋白含量、丙二醛(MDA)、谷胱甘肽过氧化物酶(GSH-Px)、超氧化物岐化酶(SOD)水平,显微镜下观察睾丸病理结构的改变。结果:SD1、SD2组大鼠的终末体质量[(248.1±25.1)g、(232.9±10.1)g]均下降,与CC组[(268.5±1.6)g]相比差异有统计学意义(P均<0.05);与CC组相比,SD2组睾丸相对质量明显升高[(54.9±3.5)×10^(-2)vs(50.0±1.3)×10^(-2),P<0.05]。与CC组相比,SD2组睾丸组织蛋白含量、MDA含量、SOD活性和GSH-Px均有显著差异[蛋白含量:(4.5±0.9)g pro/L vs 6.3±1.4)g pro/L;MDA含量:(1.3±0.3)nmol/mg pro vs(1.1±0.1)nmol/mg pro;SOD活性:(135.2±26.9)U/mg pro vs(104.3±33.1)U/mg pro;GSH-Px活性:(21.7±4.3)U/mg pro vs(15.6±4.0)U/mg pro,P均<0.05],而与SD1组比较差异无统计学意义。SD1组睾丸病理学改变不明显,但SD2组睾丸生精小管管腔变小,周围间质部分增加,间质充血水肿明显。结论:长期深慢波睡眠剥夺对大鼠睾丸组织结构产生损伤并引起氧化应激反应。
