目的:探讨慢性阻塞性肺疾病(chronic obstructive pulmonary diseases,COPD)病人压力支持通气(pressure support ventilation,PSV)时呼吸力学线性分析和非线性分析拟合效率的比较。方法:以本院英东重症医学监护中心于2004年1月至2005年...目的:探讨慢性阻塞性肺疾病(chronic obstructive pulmonary diseases,COPD)病人压力支持通气(pressure support ventilation,PSV)时呼吸力学线性分析和非线性分析拟合效率的比较。方法:以本院英东重症医学监护中心于2004年1月至2005年1月收治的14例COPD患者为研究对象,将PSV水平调到大于或等于20cmH2O,通气15min,使病人达到"接近放松"状态。分别以呼吸力学线性和非线性模型分析此状态下的压力(P)、流量(V′)和容量(V)数据,比较二者的拟合效率指标决定系数(R2)和根均方差(root mean squaredifference,RMSD)。结果:非线性分析所得RMSD值(1.95±0.93)cmH2O小于线性分析所得RMSD值(3.29±1.31)cmH2O,非线性分析所得R2值(0.96±0.03)大于线性分析所得R2值(0.84±0.05),差异均有统计学意义(P<0.05)。结论:呼吸力学的非线性模型比线性模型更加适合COPD病人压力支持通气呼吸力学分析。展开更多
To theoretically research the influence of a varied Al component on the active layer of AlGaN photocathodes,the first principle based on density functional theory is used to calculate the formation energy and band str...To theoretically research the influence of a varied Al component on the active layer of AlGaN photocathodes,the first principle based on density functional theory is used to calculate the formation energy and band structure of AlxGa（1-x）N with x at 0,0.125,0.25,0.325,and 0.5.The calculation results show that the formation energy declines along with the Al component rise,while the band gap is increasing with Al component increasing.AlxGa（1-x）N with x at 0,0.125,0.25,0.325,and 0.5 are direct band gap semiconductors,and their absorption coefficient curves have the same variation tendency.For further study,we designed two kinds of reflection-mode AlGaN photocathode samples.Sample 1 has an AlxGa（1-x）N active layer with varied Al component ranging from0.5 to 0 and decreasing from the bulk to the surface,while sample 2 has an AlxGa（1-x）N active layer with the fixed Al component of 0.25.Using the multi-information measurement system,we measured the spectral response of the activated samples at room temperature.Their photocathode parameters were obtained by fitting quantum efficiency curves.Results show that sample 1 has a better spectral response than sample 2 at the range of short-wavelength.This work provides a reference for the structure design of the AlGaN photocathode.展开更多
目的比较选择性最小平方拟合法(SLSF)与非选择性最小平方拟合法(NSLSF)应用于压力支持通气(pres-sure support ventilation,PSV)时的拟合效率。方法12例机械通气病人,将PSV水平调节到大于或等于20 cm HO2通气15 m in达到“接近松弛”状...目的比较选择性最小平方拟合法(SLSF)与非选择性最小平方拟合法(NSLSF)应用于压力支持通气(pres-sure support ventilation,PSV)时的拟合效率。方法12例机械通气病人,将PSV水平调节到大于或等于20 cm HO2通气15 m in达到“接近松弛”状态。分别以SLSF法和NSLSF法分析“接近松弛”状态时的气道压力(Paw)、流量(V')和容积(V)数据,比较SLSF法与NSLSF法拟合效率指标根均方差(RMSD)和决定系数(R2)的大小。结果SLSF法所得之RMSD值小于NSLSF法,SLSF法所得之R2值大于NSLSF法,差异均有显著性(P<0.05)。结论当应用于较高PSV水平通气时,SLSF法的拟合效率比NSLSF法高,SLSF法更适合于拟合PSV通气“接近松弛”状态时的呼吸力学参数。展开更多
文摘目的:探讨慢性阻塞性肺疾病(chronic obstructive pulmonary diseases,COPD)病人压力支持通气(pressure support ventilation,PSV)时呼吸力学线性分析和非线性分析拟合效率的比较。方法:以本院英东重症医学监护中心于2004年1月至2005年1月收治的14例COPD患者为研究对象,将PSV水平调到大于或等于20cmH2O,通气15min,使病人达到"接近放松"状态。分别以呼吸力学线性和非线性模型分析此状态下的压力(P)、流量(V′)和容量(V)数据,比较二者的拟合效率指标决定系数(R2)和根均方差(root mean squaredifference,RMSD)。结果:非线性分析所得RMSD值(1.95±0.93)cmH2O小于线性分析所得RMSD值(3.29±1.31)cmH2O,非线性分析所得R2值(0.96±0.03)大于线性分析所得R2值(0.84±0.05),差异均有统计学意义(P<0.05)。结论:呼吸力学的非线性模型比线性模型更加适合COPD病人压力支持通气呼吸力学分析。
基金supported by the National Natural Science Foundation of China(Nos.61308089,6144005)the Public Technology Applied Research Project of Zhejiang Province(No.2013C31068)
文摘To theoretically research the influence of a varied Al component on the active layer of AlGaN photocathodes,the first principle based on density functional theory is used to calculate the formation energy and band structure of AlxGa（1-x）N with x at 0,0.125,0.25,0.325,and 0.5.The calculation results show that the formation energy declines along with the Al component rise,while the band gap is increasing with Al component increasing.AlxGa（1-x）N with x at 0,0.125,0.25,0.325,and 0.5 are direct band gap semiconductors,and their absorption coefficient curves have the same variation tendency.For further study,we designed two kinds of reflection-mode AlGaN photocathode samples.Sample 1 has an AlxGa（1-x）N active layer with varied Al component ranging from0.5 to 0 and decreasing from the bulk to the surface,while sample 2 has an AlxGa（1-x）N active layer with the fixed Al component of 0.25.Using the multi-information measurement system,we measured the spectral response of the activated samples at room temperature.Their photocathode parameters were obtained by fitting quantum efficiency curves.Results show that sample 1 has a better spectral response than sample 2 at the range of short-wavelength.This work provides a reference for the structure design of the AlGaN photocathode.
文摘目的比较选择性最小平方拟合法(SLSF)与非选择性最小平方拟合法(NSLSF)应用于压力支持通气(pres-sure support ventilation,PSV)时的拟合效率。方法12例机械通气病人,将PSV水平调节到大于或等于20 cm HO2通气15 m in达到“接近松弛”状态。分别以SLSF法和NSLSF法分析“接近松弛”状态时的气道压力(Paw)、流量(V')和容积(V)数据,比较SLSF法与NSLSF法拟合效率指标根均方差(RMSD)和决定系数(R2)的大小。结果SLSF法所得之RMSD值小于NSLSF法,SLSF法所得之R2值大于NSLSF法,差异均有显著性(P<0.05)。结论当应用于较高PSV水平通气时,SLSF法的拟合效率比NSLSF法高,SLSF法更适合于拟合PSV通气“接近松弛”状态时的呼吸力学参数。
