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多体分离回追现象与方案验证
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作者 李晓轩 杨依峰 +2 位作者 张利嵩 秦绪国 戈庆明 《导弹与航天运载技术》 CSCD 北大核心 2021年第6期69-72,共4页
在高超声速底流区内进行分离时,由于底流区内流动动压极低,分离体分离后具有极大的回追风险。为了解决分离体回追问题,提出了“后抛+侧抛”的分离方案,并对该分离方案进行了数值仿真分析,仿真结果表明该方案可以有效解决底流区分离时的... 在高超声速底流区内进行分离时,由于底流区内流动动压极低,分离体分离后具有极大的回追风险。为了解决分离体回追问题,提出了“后抛+侧抛”的分离方案,并对该分离方案进行了数值仿真分析,仿真结果表明该方案可以有效解决底流区分离时的分离体回追问题。 展开更多
关键词 高超声速 底流区 分离 回追
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改进的BFGS算法在一种新搜索下的收敛性 被引量:1
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作者 王海滨 《河北理工学院学报》 2006年第2期103-106,共4页
李正峰提出了一类改进的BFGS算法,并在目标函数为一致凸的条件下,证明了带有Wolf线搜索的该算法具有全局收敛性。刘光辉提出了一种与回追搜索(backtracking linesearch)有关的可行线性搜索。证明在这种新搜索下,改进的BFGS算法亦县有全... 李正峰提出了一类改进的BFGS算法,并在目标函数为一致凸的条件下,证明了带有Wolf线搜索的该算法具有全局收敛性。刘光辉提出了一种与回追搜索(backtracking linesearch)有关的可行线性搜索。证明在这种新搜索下,改进的BFGS算法亦县有全局收敛性。 展开更多
关键词 改进的BFGS算法 改变的回追搜索 全局收敛性
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Transcutaneous cervical esophagus ultrasound in adults: Relation with ambulatory 24-h pH-monitoring and esophageal manometry
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作者 Sabite Kacar Selma Uysal +4 位作者 Sedef Kuran Ulku Dagli Yasemin Ozin Erdem Karabulut Nurgul Sasmaz 《World Journal of Gastroenterology》 SCIE CAS CSCD 2007年第39期5245-5252,共8页
AIM: To determine the gastroesophageal refl uxate in the cervical esophagus (CE) and measure transcutaneous cervical esophageal ultrasound (TCEUS) f indings [anterior wall thickness (WT) of CE, esophageal luminal diam... AIM: To determine the gastroesophageal refl uxate in the cervical esophagus (CE) and measure transcutaneous cervical esophageal ultrasound (TCEUS) f indings [anterior wall thickness (WT) of CE, esophageal luminal diameter (ELD), esophageal diameter (ED)]; to compare TCEUS findings in the patient subgroups divided according to 24-h esophageal pH monitoring and manometry; and to investigate possible cut-off values according to the TCEUS f indings as a predictor of gastroesophageal refl ux (GER). METHODS: In 45/500 patients, refl uxate was visualized in TCEUS. 38/45 patients underwent esophagogastroduo denoscopy (EGD), 24-h pH monitoring and manometry. RESULTS: The 38 patients were grouped according to 24-h pH monitoring as follows: Group A: GER-positive (n = 20) [Includes Group B: isolated proximal refl ux (PR) (n = 6), Group C: isolated distal reflux (DR) (n = 6), and Group D: both PR/DR (n = 8)]; Group E: no refl ux (n = 13); and Group F: hypersensitive esophagus (HSE) (n = 5). Groups B + D indicated total PR patients (n = 14), Groups E + F refl ux-negatives with HSE (n = 18), and Groups A + F refl ux-positives with HSE (n = 25). When the 38 patients were grouped according to manometry fi ndings, 24 had normal esophageal manometry; 7 had hypotensive and 2 had hypertensive lower esophageal sphincter (LES); and 5 had ineffective esophageal motility disorder (IEM). The ELD measurement was greater in group A + F than group E (P = 0.023, 5.0 ± 1.3 vs 3.9 ± 1.4 mm). In 27/38 patients, there was at least one pathologic acid refl ux and/or pathologic manometry fi nding. The cut-off value for ELD of 4.83 mm had 79% sensitivity and 61% specificity in predicting the PRbetween Groups B + D and E (AUC = 0.775, P = 0.015). CONCLUSION: Visualizing refluxate in TCEUS was useful as a pre-diagnostic tool for estimating GER or manometric pathology in 71.1% of adults in our study, but it was not diagnostic for CE WT. 展开更多
关键词 Ambulatory 24-h pH monitoring Cervical esophageal ultrasound Gastroesophageal reflux Esophageal manometry Esophageal refluxate
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