在计算大规模介质-金属复合周期结构的电磁散射时,传统积分方程方法存在未知量大、存储占用多和计算时间长等问题。本文采用广义PMCHWT(Poggio-Miller-Chang-Harrington-Wu-Tsai)-电场积分方程(electric field integral equation,EFIE)...在计算大规模介质-金属复合周期结构的电磁散射时,传统积分方程方法存在未知量大、存储占用多和计算时间长等问题。本文采用广义PMCHWT(Poggio-Miller-Chang-Harrington-Wu-Tsai)-电场积分方程(electric field integral equation,EFIE)方法计算均匀介质-金属复合结构的电磁响应。该方法通过在分界面处设置区域连接模型(contact-region modeling,CRM)来保证边界处的连续性。为加速子阵列阻抗矩阵填充,采用快速偶极子方法(fast dipole method,FDM)来提高计算效率并降低内存占用。结合子全域(sub-entire-domain,SED)基函数方法,子阵列的电流分布特征可被推广到大规模介质-金属复合周期结构的电磁场计算中。数值算例表明,本文方法能够在保证计算精度的同时大幅度降低计算代价,内存占用降低至商业软件Altair FEKO(使用多层快速多极子方法)的1/10,计算误差在2.6 dB以内。展开更多
将食用植物油中的脂肪酸转化为相应的脂肪酸甲酯,并采用立体结构参数Steric and Electronic Descriptors(SEDs)表征其分子结构,然后运用多元线性回归(MLR)方法,建立了预测食用植物油中脂肪酸(甲酯)的定量结构-色谱保留相关(QSRR)模型,...将食用植物油中的脂肪酸转化为相应的脂肪酸甲酯,并采用立体结构参数Steric and Electronic Descriptors(SEDs)表征其分子结构,然后运用多元线性回归(MLR)方法,建立了预测食用植物油中脂肪酸(甲酯)的定量结构-色谱保留相关(QSRR)模型,同时采用内部及外部双重验证的方法对所建模型的稳定性能和预测能力进行了分析和验证。建模计算值、留一法(LOO)交互检验(CV)预测值和外部样本预测值的相关系数R、R LOO、Q2ext分别为0.9990、0.9970、0.9860。结果表明,SEDs参数能较好地表征食用植物油中的脂肪酸甲酯分子的结构信息,所建立的QSRR模型具有良好的稳定性和预测能力,为间接分析鉴定食用植物油中脂肪酸提供了一种方便有效的新途径。展开更多
BACKGROUND Although critically ill pediatric patients can benefit from the use of sedation,it can cause side effects and even iatrogenic complications.Since pediatric patients cannot adequately express the intensity o...BACKGROUND Although critically ill pediatric patients can benefit from the use of sedation,it can cause side effects and even iatrogenic complications.Since pediatric patients cannot adequately express the intensity or location of the pain,discriminating the cause of their irritability and agitation can be more complicated than in adults.Thus,sedation therapy for children requires more careful attention.AIM To evaluate the association of the internal parental care protocol and the reduction in pediatric intensive care unit(PICU)postoperatively.METHODS This retrospective cohort study was carried out in the PICU of the tertiary medical center in Kazakhstan.The internal parental care protocol was developed and implemented by critical care team.During the pandemic,restrictions were also placed on parental presence in the PICU.We compare two groups:During restriction and after return to normal.The level of agitation was evaluated using the Richmond Agitation-Sedation Scale.Univariate and multivariate logistic regression analyses were performed to examine associations of parental care with sedation therapy.RESULTS A total of 289 patients were included in the study.Of them,167 patients were hospitalized during and 122 after the restrictions of parental care.In multivariate analysis,parental care was associated with lower odds of prescribing diazepam(odds ratio=0.11,95%confidence interval:0.05-0.25),controlling for age,sex,cerebral palsy,and type of surgery.CONCLUSION The results of this study show that parental care was associated only with decreased odds of prescribing sedative drugs,while no differences were observed for analgesics.展开更多
文摘在计算大规模介质-金属复合周期结构的电磁散射时,传统积分方程方法存在未知量大、存储占用多和计算时间长等问题。本文采用广义PMCHWT(Poggio-Miller-Chang-Harrington-Wu-Tsai)-电场积分方程(electric field integral equation,EFIE)方法计算均匀介质-金属复合结构的电磁响应。该方法通过在分界面处设置区域连接模型(contact-region modeling,CRM)来保证边界处的连续性。为加速子阵列阻抗矩阵填充,采用快速偶极子方法(fast dipole method,FDM)来提高计算效率并降低内存占用。结合子全域(sub-entire-domain,SED)基函数方法,子阵列的电流分布特征可被推广到大规模介质-金属复合周期结构的电磁场计算中。数值算例表明,本文方法能够在保证计算精度的同时大幅度降低计算代价,内存占用降低至商业软件Altair FEKO(使用多层快速多极子方法)的1/10,计算误差在2.6 dB以内。
文摘将食用植物油中的脂肪酸转化为相应的脂肪酸甲酯,并采用立体结构参数Steric and Electronic Descriptors(SEDs)表征其分子结构,然后运用多元线性回归(MLR)方法,建立了预测食用植物油中脂肪酸(甲酯)的定量结构-色谱保留相关(QSRR)模型,同时采用内部及外部双重验证的方法对所建模型的稳定性能和预测能力进行了分析和验证。建模计算值、留一法(LOO)交互检验(CV)预测值和外部样本预测值的相关系数R、R LOO、Q2ext分别为0.9990、0.9970、0.9860。结果表明,SEDs参数能较好地表征食用植物油中的脂肪酸甲酯分子的结构信息,所建立的QSRR模型具有良好的稳定性和预测能力,为间接分析鉴定食用植物油中脂肪酸提供了一种方便有效的新途径。
文摘BACKGROUND Although critically ill pediatric patients can benefit from the use of sedation,it can cause side effects and even iatrogenic complications.Since pediatric patients cannot adequately express the intensity or location of the pain,discriminating the cause of their irritability and agitation can be more complicated than in adults.Thus,sedation therapy for children requires more careful attention.AIM To evaluate the association of the internal parental care protocol and the reduction in pediatric intensive care unit(PICU)postoperatively.METHODS This retrospective cohort study was carried out in the PICU of the tertiary medical center in Kazakhstan.The internal parental care protocol was developed and implemented by critical care team.During the pandemic,restrictions were also placed on parental presence in the PICU.We compare two groups:During restriction and after return to normal.The level of agitation was evaluated using the Richmond Agitation-Sedation Scale.Univariate and multivariate logistic regression analyses were performed to examine associations of parental care with sedation therapy.RESULTS A total of 289 patients were included in the study.Of them,167 patients were hospitalized during and 122 after the restrictions of parental care.In multivariate analysis,parental care was associated with lower odds of prescribing diazepam(odds ratio=0.11,95%confidence interval:0.05-0.25),controlling for age,sex,cerebral palsy,and type of surgery.CONCLUSION The results of this study show that parental care was associated only with decreased odds of prescribing sedative drugs,while no differences were observed for analgesics.
