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基于冠状动脉CT血管造影的腔内校正密度参数与血流储备分数在判断冠心病短期预后不良中的价值
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作者 黄小伟 李伟 +1 位作者 陈楠楠 赵琳 《大医生》 2023年第23期103-106,共4页
目的 研究基于冠状动脉CT血管造影(CTA)的腔内校正密度参数与血流储备分数(FFR_(CT))判断冠心病患者短期预后不良的价值,为临床提供参考。方法 选取2022年4月至2023年4月通用环球中铁西安医院收治的140例冠心病患者为研究对象进行回顾... 目的 研究基于冠状动脉CT血管造影(CTA)的腔内校正密度参数与血流储备分数(FFR_(CT))判断冠心病患者短期预后不良的价值,为临床提供参考。方法 选取2022年4月至2023年4月通用环球中铁西安医院收治的140例冠心病患者为研究对象进行回顾性分析,患者均接受规范治疗,根据随访3个月内是否发生主要不良心血管事件(MACE)将患者分为预后不良组(发生MACE,18例)和预后良好组(未发生MACE,122例)。比较两组患者临床特征指标、血清指标、冠状动脉CTA检查相关参数,分析冠心病患者短期预后不良的影响因素,分析腔内校正密度参数与FFR_(CT)判断冠心病患者短期预后不良的临床价值。结果 预后不良组患者高血压发生率高于预后良好组,美国纽约心脏病协会(NYHA)心功能分级高于预后良好组,病变血管多于预后良好组(P<0.05)。预后不良组患者超敏C反应蛋白(hs-CRP)和肌钙蛋白I(cTnI)水平高于预后良好组(P<0.05)。预后不良组患者FFR_(CT)低于预后良好组,校正后密度差值(DCCO)和直接密度值比(R)高于预后良好组(P<0.05)。多因素Logistic分析结果显示,NYHA心功能分级Ⅲ~Ⅳ级、血清cTnI水平、DCCO及R升高是冠心病患者短期预后不良的独立危险因素,FFR_(CT)升高是保护因素(P<0.05)。根据多因素分析结果建立预测模型Y=0.734×(X_(2))+0.962×(X_5)-0.298×(X_6)+0.622×(X_7)+0.768×(X_8),受试者操作特征(ROC)曲线分析结果显示,预测模型判断冠心病患者短期预后不良的曲线下面积(AUC)为0.804(P<0.05)。结论 基于冠状动脉CTA的腔内校正密度参数与FFR_(CT)建立预测模型,可用于判断冠心病患者短期预后不良。 展开更多
关键词 冠状动脉CT血管造影 内校正密度参数 血流储备分数 冠心病 预后不良
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药物经济学评价中Markov模型的周期内校正方法探讨 被引量:9
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作者 沃田 陈磊 席晓宇 《中国药房》 CAS 北大核心 2020年第8期980-984,共5页
目的:为减少药物经济学研究中Markov模型的误差提供参考。方法:参考国外相关文献,解释Markov模型误差产生的原理,并介绍常用的半周期法、梯形法、Simpson’s 1/3法、Simpson’s 3/8法、生命表法及其在Excel、TreeAge软件中的实现方法。... 目的:为减少药物经济学研究中Markov模型的误差提供参考。方法:参考国外相关文献,解释Markov模型误差产生的原理,并介绍常用的半周期法、梯形法、Simpson’s 1/3法、Simpson’s 3/8法、生命表法及其在Excel、TreeAge软件中的实现方法。结果与结论:Markov模型因离散化过程而产生误差,使用周期内校正方法可校正这一误差。半周期法是最常用的校正方法,是通过增加第1周期一半的结果并减去最后1周期一半的结果进行校正;梯形法的校正是以区间首尾端点值的均值代表该区间,以直角梯形的面积作为累计的结果;Simpson’s 1/3法和Simpson’s 3/8法则在梯形法的基础上在区间中插值并以插值点所在的连续曲线代表整个曲线;寿命表法的校正中,生存人年数为该年龄组的组距与该年龄组和下一年龄组尚存人数的均值的乘积,生存人年数则为各年龄组生存总人年数的总和。在Excel中,可根据方法原理设置函数来实现校正;而在TreeAge软件中,可通过设置Init Rwd、Incr Rwd、Final Rwd的函数表达式来实现校正。在使用Markov模型进行药物经济学评价时,对于周期校正方法的选择,若从建模的易用性、适用情形的广泛性等角度出发,建议使用梯形法;从结果的精确性角度出发,则建议使用Simpson’s 1/3法,以提高Markov模型的准确度。 展开更多
关键词 药物经济学 MARKOV模型 周期内校正 半周期法 梯形法 Simpson’s 1/3法 Simpson’s 3/8法 寿命表法
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Ku波段一体化开口脊波导阵列天线
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作者 詹珍贤 《雷达科学与技术》 北大核心 2016年第5期554-557,共4页
设计了一种集成内校正通道的Ku波段一体化开口脊波导阵列天线,由底部的同轴连接器馈电,经渐变阶梯状的过渡匹配段同轴波导变换,并压缩波导截面尺寸以实现宽带二维宽扫性能。在开口脊波导底部设置耦合槽和校正波导,形成内校正通道,并将... 设计了一种集成内校正通道的Ku波段一体化开口脊波导阵列天线,由底部的同轴连接器馈电,经渐变阶梯状的过渡匹配段同轴波导变换,并压缩波导截面尺寸以实现宽带二维宽扫性能。在开口脊波导底部设置耦合槽和校正波导,形成内校正通道,并将馈电连接器偏置,使一条校正波导可以耦合相邻的两列天线单元,实现了高集成度一体化设计。设计制造了8×8单元的天线阵面,实测结果表明,该天线驻波小于2的相对带宽为14%,可实现二维±60°的宽角扫描,天线增益约21.8dB,辐射效率81.7%。该天线具有宽带、二维宽扫、结构紧凑、高集成度等优点,且实现了小单元间距相控阵天线的内校正功能。 展开更多
关键词 相控阵天线 开口波导 一体化设计 内校正
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A predictor-corrector interior-point algorithmfor monotone variational inequality problems 被引量:2
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作者 梁昔明 钱积新 《Journal of Zhejiang University Science》 CSCD 2002年第3期321-325,共5页
Mehrotra's recent suggestion of a predictor corrector variant of primal dual interior point method for linear programming is currently the interior point method of choice for linear programming. In this work t... Mehrotra's recent suggestion of a predictor corrector variant of primal dual interior point method for linear programming is currently the interior point method of choice for linear programming. In this work the authors give a predictor corrector interior point algorithm for monotone variational inequality problems. The algorithm was proved to be equivalent to a level 1 perturbed composite Newton method. Computations in the algorithm do not require the initial iteration to be feasible. Numerical results of experiments are presented. 展开更多
关键词 Variational inequality problems(VIP) Predictor corrector interior point algorithm Numerical experiments
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A novel dense spectrum correction algorithm for extracting vibration signals in internal combustion engine and its application 被引量:3
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作者 张志刚 鄂加强 张桂香 《Journal of Central South University》 SCIE EI CAS 2012年第10期2810-2815,共6页
The algorithm of dense spectrum correction has been raised and proved based on the correction of discrete spectrum by fast Fourier transform.The result of simulation shows that such algorithm has advantages of high ac... The algorithm of dense spectrum correction has been raised and proved based on the correction of discrete spectrum by fast Fourier transform.The result of simulation shows that such algorithm has advantages of high accuracy and small amount of calculation.The algorithm has been successfully applied to the analysis of vibration signals from internal combustion engine.To calculate discrete spectrum,fast Fourier transform has been used to calculate the discrete spectrum by the signals acquired by the sensors on the oil pan,and the signal has been extracted from the mixed signals. 展开更多
关键词 fast Fourier transform discrete spectrum correction dense spectrum correction signal extracting
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Catenary action of restrained steel beam against progressive collapse of steel frameworks 被引量:1
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作者 李国强 王开强 +1 位作者 刘玉姝 陈素文 《Journal of Central South University》 SCIE EI CAS 2012年第2期537-546,共10页
The changing law of internal forces during the whole deformation development process was analyzed. The process was divided into five stages based on the internal force state of the beam and the assumptions of internal... The changing law of internal forces during the whole deformation development process was analyzed. The process was divided into five stages based on the internal force state of the beam and the assumptions of internal force relationship of five stages were proposed. Then, the formulas for determining the midspan deflection of the steel beam under distributed load, which was restrained both in rotational and axial directions, were obtained using restraint coefficient method and rigid-plastic mechanism, thereby the deformation development process was expressed accurately in a quantified way. Priority was given to the analysis of the process from bending to tension-bending, then the final state totally depends on tension to resist the external loads, that is the problem of catenary action of the restrained beam under distributed load. Additionally, finite element analysis was carried out with soitware ABAQUS6.7 on a restrained steel beam under distributed load with different axial and rotational restraint coefficients. The accuracy of the formulas presented was verified by the results of the behavior of the restrained beams. Finally, error analysis was conducted and some formulas were corrected according to the reasons of errors. The calculated results of corrected formulas match the FEM analysis results better, thus the accuracy of these formulas is improve . 展开更多
关键词 restrained steel beam catenary action rigid-plastic mechanism numerical analysis formula correction
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