This paper introduces a practical solving scheme of gradetransition trajectory optimization(GTTO) problems under typical certificate-checking–updating framework. Due to complicated kinetics of polymerization,differen...This paper introduces a practical solving scheme of gradetransition trajectory optimization(GTTO) problems under typical certificate-checking–updating framework. Due to complicated kinetics of polymerization,differential/algebraic equations(DAEs) always cause great computational burden and system non-linearity usually makes GTTO non-convex bearing multiple optima. Therefore, coupled with the three-stage decomposition model, a three-section algorithm of dynamic programming(TSDP) is proposed based on the general iteration mechanism of iterative programming(IDP) and incorporated with adaptivegrid allocation scheme and heuristic modifications. The algorithm iteratively performs dynamic programming with heuristic modifications under constant calculation loads and adaptively allocates the valued computational resources to the regions that can further improve the optimality under the guidance of local error estimates. TSDP is finally compared with IDP and interior point method(IP) to verify its efficiency of computation.展开更多
An algorithm for precisely calculating the inductance of a three-section solenoid is presented, which is based on summing the layer self-inductances and the mutual inductances. A theoretical model with ex plicit expre...An algorithm for precisely calculating the inductance of a three-section solenoid is presented, which is based on summing the layer self-inductances and the mutual inductances. A theoretical model with ex plicit expressions is firstly developed to calculate the self-inductance of a single layer, and then numerical calcu lation of the mutual inductance between two layers is introduced. Using the presented computation method, the inductance of a solenoid designed in the experiment is successfully calculated （4.30 mH）, which has a difference of less than 1% from the experimental data.展开更多
By use of geostrophic momentum approximation,the analytical expressions of the wind distribution within the planetary boundary layer and the vertical velocity at the top of the boundary layer are obtained when the dis...By use of geostrophic momentum approximation,the analytical expressions of the wind distribution within the planetary boundary layer and the vertical velocity at the top of the boundary layer are obtained when the distribution of eddy transfer coefficient k is divided into three sections:k_1z(z_0≤z<h_1),k_2(h_1≤z<h_2), and k_3(h_2≤z).The results are in agreement with the observations.In particular,the wind profile in the surface layer(z_0≤z<h_1)coincides with the logarithmic distribution.The maximum angle between winds near the surface and at the bottom of the free atmosphere is only about 30°.This work improves the work of Wu and Blumen(1982)who introduced the geostrophic momentum approximation to the boundary layer.The solutions in barotropic and neutral conditions have been also extended to the baroclinic and stratified atmosphere.展开更多
目的:探讨子宫肌层3层缝合对剖宫产术后憩室大小的影响及子宫切口憩室(CSD)形成的相关因素。方法:回顾性分析2022年4~11月于华东师范大学附属芜湖医院行剖宫产术的240例产妇的临床资料,根据子宫肌层缝合方式的不同分为3层缝合组(124例)...目的:探讨子宫肌层3层缝合对剖宫产术后憩室大小的影响及子宫切口憩室(CSD)形成的相关因素。方法:回顾性分析2022年4~11月于华东师范大学附属芜湖医院行剖宫产术的240例产妇的临床资料,根据子宫肌层缝合方式的不同分为3层缝合组(124例)和双层缝合组(116例);另根据术后是否形成CSD将产妇分为CSD组(23例)和非CSD组(217例)。对比3层缝合组与双层缝合组产妇的临床特点,采用多因素Logistic回归分析CSD形成的独立影响因素并构建人工神经网络模型;采用受试者工作特征(ROC)曲线、校准曲线和临床决策曲线进行模型验证。结果:①3层缝合组产妇的子宫肌层瘢痕厚度显著高于双层缝合组(7.06±2.09 mm vs.5.68±1.97 mm);而CSD形成情况(4.03%vs.15.52%)和憩室大小(0.36±0.09 ml vs.0.47±0.12 ml)则显著低于双层缝合组,差异均有统计学意义(P<0.05);②多因素分析示,子宫后屈、剖宫产次数≥2次、胎膜早破、围产期感染、剖宫产时机(择期)是影响CSD形成的独立危险因素(OR>1,P<0.05),而子宫肌层3层缝合是保护性因素(OR<1,P<0.05);③人工神经网络预测模型显示剖宫产次数、胎膜早破以及是否进行3层缝合所占权重均较高,经ROC曲线、校准曲线和临床决策曲线验证表明该模型预测能力良好。结论:CSD的形成与子宫后屈、剖宫产次数、胎膜早破、围产期感染、剖宫产时机等指标有关,临床应重点关注,此外,子宫肌层3层缝合可降低CSD的形成概率,在临床上值得推广应用。展开更多
基金Supported by the National Basic Research Program of China(2012CB720500)the National High Technology Research and Development Program of China(2013AA040702)
文摘This paper introduces a practical solving scheme of gradetransition trajectory optimization(GTTO) problems under typical certificate-checking–updating framework. Due to complicated kinetics of polymerization,differential/algebraic equations(DAEs) always cause great computational burden and system non-linearity usually makes GTTO non-convex bearing multiple optima. Therefore, coupled with the three-stage decomposition model, a three-section algorithm of dynamic programming(TSDP) is proposed based on the general iteration mechanism of iterative programming(IDP) and incorporated with adaptivegrid allocation scheme and heuristic modifications. The algorithm iteratively performs dynamic programming with heuristic modifications under constant calculation loads and adaptively allocates the valued computational resources to the regions that can further improve the optimality under the guidance of local error estimates. TSDP is finally compared with IDP and interior point method(IP) to verify its efficiency of computation.
文摘An algorithm for precisely calculating the inductance of a three-section solenoid is presented, which is based on summing the layer self-inductances and the mutual inductances. A theoretical model with ex plicit expressions is firstly developed to calculate the self-inductance of a single layer, and then numerical calcu lation of the mutual inductance between two layers is introduced. Using the presented computation method, the inductance of a solenoid designed in the experiment is successfully calculated （4.30 mH）, which has a difference of less than 1% from the experimental data.
文摘By use of geostrophic momentum approximation,the analytical expressions of the wind distribution within the planetary boundary layer and the vertical velocity at the top of the boundary layer are obtained when the distribution of eddy transfer coefficient k is divided into three sections:k_1z(z_0≤z<h_1),k_2(h_1≤z<h_2), and k_3(h_2≤z).The results are in agreement with the observations.In particular,the wind profile in the surface layer(z_0≤z<h_1)coincides with the logarithmic distribution.The maximum angle between winds near the surface and at the bottom of the free atmosphere is only about 30°.This work improves the work of Wu and Blumen(1982)who introduced the geostrophic momentum approximation to the boundary layer.The solutions in barotropic and neutral conditions have been also extended to the baroclinic and stratified atmosphere.
文摘目的:探讨子宫肌层3层缝合对剖宫产术后憩室大小的影响及子宫切口憩室(CSD)形成的相关因素。方法:回顾性分析2022年4~11月于华东师范大学附属芜湖医院行剖宫产术的240例产妇的临床资料,根据子宫肌层缝合方式的不同分为3层缝合组(124例)和双层缝合组(116例);另根据术后是否形成CSD将产妇分为CSD组(23例)和非CSD组(217例)。对比3层缝合组与双层缝合组产妇的临床特点,采用多因素Logistic回归分析CSD形成的独立影响因素并构建人工神经网络模型;采用受试者工作特征(ROC)曲线、校准曲线和临床决策曲线进行模型验证。结果:①3层缝合组产妇的子宫肌层瘢痕厚度显著高于双层缝合组(7.06±2.09 mm vs.5.68±1.97 mm);而CSD形成情况(4.03%vs.15.52%)和憩室大小(0.36±0.09 ml vs.0.47±0.12 ml)则显著低于双层缝合组,差异均有统计学意义(P<0.05);②多因素分析示,子宫后屈、剖宫产次数≥2次、胎膜早破、围产期感染、剖宫产时机(择期)是影响CSD形成的独立危险因素(OR>1,P<0.05),而子宫肌层3层缝合是保护性因素(OR<1,P<0.05);③人工神经网络预测模型显示剖宫产次数、胎膜早破以及是否进行3层缝合所占权重均较高,经ROC曲线、校准曲线和临床决策曲线验证表明该模型预测能力良好。结论:CSD的形成与子宫后屈、剖宫产次数、胎膜早破、围产期感染、剖宫产时机等指标有关,临床应重点关注,此外,子宫肌层3层缝合可降低CSD的形成概率,在临床上值得推广应用。
