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分数阶傅里叶变换的快速计算新方法 被引量:23
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作者 赵兴浩 陶然 +1 位作者 邓兵 王越 《电子学报》 EI CAS CSCD 北大核心 2007年第6期1089-1093,共5页
本文提出了一种分数阶傅里叶变换(FRFT)高分辨(Zoom-FRFT)算法,通过设置谱区间和输出点数M,可实现任意局部谱的高分辨计算.随后,针对M很小时Zoom-FRFT运算效率低的问题,提出了基于Horner的单点快速计算(SP-FRFT)方法,并针对零点计算做... 本文提出了一种分数阶傅里叶变换(FRFT)高分辨(Zoom-FRFT)算法,通过设置谱区间和输出点数M,可实现任意局部谱的高分辨计算.随后,针对M很小时Zoom-FRFT运算效率低的问题,提出了基于Horner的单点快速计算(SP-FRFT)方法,并针对零点计算做出进一步简化.利用SP-FRFT可提高少量点输出时的计算效率,也可用于非均匀采样点计算.仿真结果验证了算法的有效性. 展开更多
关键词 分数阶傅里叶变换(FRFT) 分解型算法 高分辨计算 单点快速计算
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支气管哮喘合并慢性阻塞性肺疾病患者HRCT肺气肿容积测定及其与肺功能的相关性 被引量:22
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作者 黄爱霞 姚国相 +5 位作者 金崇武 刘宏伟 刘温娟 张华伟 张燕 鲁立文 《中国医药导报》 CAS 2019年第2期113-116,共4页
目的分析支气管哮喘合并慢性阻塞性肺疾病(ACO)患者胸部高分辨CT(HRCT)所示肺气肿程度并探讨其与肺功能的相关性。方法收集2013年3月~2015年3月上海健康医学院附属第六人民医院南院呼吸科就诊的初步诊断为支气管哮喘和/或慢性阻塞性肺... 目的分析支气管哮喘合并慢性阻塞性肺疾病(ACO)患者胸部高分辨CT(HRCT)所示肺气肿程度并探讨其与肺功能的相关性。方法收集2013年3月~2015年3月上海健康医学院附属第六人民医院南院呼吸科就诊的初步诊断为支气管哮喘和/或慢性阻塞性肺疾病(COPD)患者69例,根据慢性阻塞性肺疾病全球创议(GOLD)及全球哮喘防治创议(GINA)指南诊断标准将患者分为三组:哮喘组(18例),COPD组(37例),ACO组(14例)。所有患者均接受肺功能测定及胸部HRCT扫描。由Myrian软件对CT图像进行三维重建,辨识肺组织及低密度区,并计算CT值小于-950 Hu的低密度区比例(LAA%)。结果哮喘组和COPD组及ACO组比较,左肺LAA%、右肺LAA%及全肺LAA%差异有高度统计学意义(P <0.01),ACO组和COPD组比较,左肺LAA%、右肺LAA%及全肺LAA%差异无统计学意义(P> 0.05)。ACO组左肺LAA%、右肺LAA%及全肺LAA%与FEV1%预计值(r=-0.611、-0.635、-0.672)及FEV1/FVC%(r=-0.699、-0.673、-0.745)均呈负相关(均P <0.05),而与第1秒用力呼气容积占肺活量的比值(RV/TLC%)呈正相关(r=0.451、0.381、0.446,均P <0.05)。结论 ACO患者HRCT所示肺气肿与COPD患者相似,较哮喘患者严重;ACO患者HRCT所示肺气肿可在一定程度反映肺通气功能情况。 展开更多
关键词 支气管哮喘合并慢性阻塞性肺疾病 高分辨计算机体层成像 肺气肿 肺功能
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COVID-19不同时间段CT影像学动态变化及临床相关性
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作者 舒恩芬 杨伟斌 +3 位作者 周刚 舒锦尔 徐浩侃 纪建松 《浙江临床医学》 2020年第7期979-981,共3页
目的探讨新型冠状病毒肺炎(COVID-19)不同时间阶段CT影像学动态变化特征及其临床相关性.方法回顾性分析2020年1月至2月69例经核酸检查确诊的COVID-19患者的临床资料和CT平扫图像,最终入组60例,记录并分析患者不同阶段(1~4d、5~13d)的病... 目的探讨新型冠状病毒肺炎(COVID-19)不同时间阶段CT影像学动态变化特征及其临床相关性.方法回顾性分析2020年1月至2月69例经核酸检查确诊的COVID-19患者的临床资料和CT平扫图像,最终入组60例,记录并分析患者不同阶段(1~4d、5~13d)的病变部位、分布、形态、数目、密度、细网格征、结节伴晕征、反晕征、支气管空气征、血管增粗征等影像特征的动态变化过程.结果CT影像显示,疾病好发于左肺下叶、右肺下叶以及外带胸膜下,23.3%的患者累及5个肺叶,当疾病进展到第二阶段时,病灶进展迅速,病灶数量快速增加,且双肺受累患者明显增加,且50%的患者出现累及5个肺叶;在第一阶段病灶多沿支气管血管束生长,最常见的形态为小斑片状或条状影,大片状影相对较少,进展至第二阶段,病灶呈大片的患者数量明显增多,且实变病灶也显著增加;在第一阶段63.3%患者呈现细网格征,40%出现血管增粗征象,33.3%患者出现空气支气管征,进展至第二阶段后,发现患者细网格征和空气支气管征显著增多.进展至第三阶段时,81.6%的患者出现病灶吸收,病情逐渐恢复,但其中13.3%的患者变化不大,3例患者(5%)疾病进展为重型COVID-19肺炎,双肺弥漫性病变,呈"白肺"表现.结论CT动态影像学征象可以准确反映病变演变及转归过程,客观评估病程进展,在新冠肺炎的病情监测、治疗和出院判断中起至关重要的作用. 展开更多
关键词 新型冠状病毒肺炎 高分辨计算机断层扫描 动态变化
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Clinical Features and Prognosis in 21 Patients with Extrinsic Allergic Alveolitis 被引量:5
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作者 Ping Wang Zuo-jun Xu +4 位作者 Wen-bing Xu Ju-hong Shi Xin-lun Tian Rui-e Feng Yuan-jue Zhu 《Chinese Medical Sciences Journal》 CAS CSCD 2009年第4期202-207,共6页
Objective To assess the spectrum of causes, clinical features, differences between disease phases, and prognosis of extrinsic allergic alveolitis (EAA). Methods Patients with EAA diagnosed at Peking Union Medical C... Objective To assess the spectrum of causes, clinical features, differences between disease phases, and prognosis of extrinsic allergic alveolitis (EAA). Methods Patients with EAA diagnosed at Peking Union Medical College Hospital from August 1983 to May 2007 were analyzed retrospectively. Their medical records were examined to gather clinical, laboratorial, radiological, and histopathological data. Patients were divided to three phases (acute, subacute, and chronic) according to clinical presentations. Follow-up data regarding treatment response, subsequent radio- logical and pulmonary function studies, and clinical outcomes were collected. Results A total of 21 cases were enrolled. Among them, 11 were subacute, 10 were chronic. The most common exposure was pet birds (6 cases, 28.6%). The primary abnormality of pulmonary function was restriction and/or reduction in diffusing capacity (12 cases, 63.2%). The most common findings on high-resolution computed tomography (HRCT) were ground-glass opacities (13 cases, 68.4%) and centri- lobular nodules (8 cases, 42.1%). Airway obstruction in pulmonary function test, emphysema, hmg cysts, and fibrosis on HRCT were more frequently seen in chronic than in subacute patients, though the differences were not statistically significant. Bronchoalveolar lavage fluid (BALF) showed lymphocytosis. The total'cell count and the percentage of neutrophils were significantly higher in subacute than in chronic patients (P〈0.05). Nonnecrotizing granulomas were seen in 8 (47.1%) cases. Improvement or normalization in symptoms, radiography, and pulmonary function test after treatment were seen in all 18 patients with avail- able follow-up data. Five patients recurred. Conclusions The characteristic abnormalities of pulmonary function, findings on HRCT, and pa- thology are essential for all phases of EAA, and the atypical manifestations such as obstruction and fibrosis can also be present frequently, particularly in chronic cases. Differential cell counts of BALF are related to the phase of the disease. The treatment response and prognosis of EAA are good. 展开更多
关键词 extrinsic allergic alveolitis bronchoalveolar lavage fluid RADIOGRAPHY HISTOPATHOLOGY PROGNOSIS
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Finite Space Complete Basis Method: Precision Computation of High-Resolutior Spectrum near Ionization Threshold
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作者 高翔 陈少豪 李家明 《Chinese Physics Letters》 SCIE CAS CSCD 2009年第1期81-83,共3页
A new method is proposed to describe quantum dynamical processes in finite space by using of a set ofdiscretized complete bases. In this method, the finite space complete basis is obtained by solving the self-consiste... A new method is proposed to describe quantum dynamical processes in finite space by using of a set ofdiscretized complete bases. In this method, the finite space complete basis is obtained by solving the self-consistent field equation with reflecting boundary conditions. Hence, both negative and positive orbital energies can be obtained. Such method can be used in systems which involve dynamics only in the reaction zone, i.e., in a finite space. To illustrate the validity of the method, we present two examples: theoretical calculation of the high excited states spectra including the continuum of sodium and barium. 展开更多
关键词 量子动力学 分辨光谱 有限空间 精密计算
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