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液压胀形环境下管材的力学行为
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作者 刘建伟 姚馨淇 +1 位作者 李玉寒 杨连发 《锻压技术》 CAS CSCD 北大核心 2019年第2期1-6,36共7页
管材液压胀形技术在轻量化、一体化制造领域具有很好的发展前景和应用价值。为了更好地分析与研究该技术,结合国内外学者的研究进展,对液压胀形下管材的力学行为进行了全面地分析与总结。首先,对金属薄壁管在液压胀形下力学模型的构建... 管材液压胀形技术在轻量化、一体化制造领域具有很好的发展前景和应用价值。为了更好地分析与研究该技术,结合国内外学者的研究进展,对液压胀形下管材的力学行为进行了全面地分析与总结。首先,对金属薄壁管在液压胀形下力学模型的构建方法进行了介绍,并分析了力学模型在塑性本构关系构建和管材成形性等方面的具体应用;然后,分析了双金属复合管液压胀形的成形机理及成形过程中的力学行为;最后,对管材液压胀形技术的发展趋势进行了阐述。通过对近年来管材液压胀形力学行为的分析与总结,为管材液压胀形技术的发展提供了有益参考。 展开更多
关键词 管材 液压胀形 力学行为 成形性 金属薄壁管 双金属复合管
Balloon dilation of Eustachian tube combined with tympanostomy tube insertion and middle ear pressure equalization therapy for recurrent secretory otitis media 预览
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作者 Gendi Yin Jingqian Tan Peng Li 《中华耳科学杂志:英文版》 CSCD 2019年第3期101-105,共5页
Objective: To report outcomes of balloon dilation Eustachian tuboplasty combined with tympanostomy tube insertion and middle ear pressure equalization therapy in treatment of recurrent secretory otitis media. Methods:... Objective: To report outcomes of balloon dilation Eustachian tuboplasty combined with tympanostomy tube insertion and middle ear pressure equalization therapy in treatment of recurrent secretory otitis media. Methods: Fifty one patients with recurrent secretory otitis media (62 ears) underwent balloon dilation of Eustachian tube and tympanic tube insertion under general anesthesia, followed by long term middle ear pressure equalization therapies. The Eustachian tube score (ETS) and Eustachian tube function questionnaire (ETDQ-7) were used for pre- and postoperative (up to 12 months) evaluation of Eustachian tube functions. Results: The mean ETS score was 2.34 ± 0.97 preoperatively, and 6.17 ± 1.54, 7.23 ± 1.62, 8.24 ± 1.97, and 7.63 ± 1.86 at 1, 3, 6 and 12 months postoperatively, respectively (P < 0.05). The ETDQ-7 score was 4.82 ± 1.07 preoperatively, and 2.20 ± 0.54, 2.32 ± 0.68, 2.53 ± 0.79, and 2.67 ± 0.76 at 1, 3, 6 and 12 months postoperatively, respectively (P < 0.05). Conclusion: Balloon dilation of Eustachian tube combined with tympanostomy and catheterization resulted in significant improvement of subjective symptoms and objective evaluation of Eustachian tube functions in most patients with recurrent secretory otitis media, as indicated by the ETS and ETDQ-7 scores, demonstrating high levels of efficacy and patient satisfaction. 展开更多
关键词 Balloon dilation eustachian tuboplasty Positive and negative AURICULAR pressure THERAPY Chronic RECURRENT secretory OTITIS media Eustachian TUBE FUNCTION score Eustachian TUBE FUNCTION questionnaire-7
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Otitis media with effusion in children:Pathophysiology,diagnosis,and treatment.A review 预览
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作者 Pauline Vanneste Cyril Page 《中华耳科学杂志:英文版》 CSCD 2019年第2期33-39,共7页
Otitis media with effusion(OME)is a frequent paediatric disorder.The condition is often asymptomatic,and so can easily be missed.However,OME can lead to hearing loss that impairs the child's language and behaviour... Otitis media with effusion(OME)is a frequent paediatric disorder.The condition is often asymptomatic,and so can easily be missed.However,OME can lead to hearing loss that impairs the child's language and behavioural development.The diagnosis is essentially clinical,and is based on otoscopy and(in some cases)tympanometry.Nasal endoscopy is only indicated in cases of unilateral OME or when obstructive adenoid hypertrophy is suspected.Otitis media with effusion is defined as the observation of middle-ear effusion at consultations three months apart.Hearing must be evaluated(using an age-appropriate audiometry technique)before and after treatment,so as not to miss another underlying cause of deafness(e.g.perception deafness).Craniofacial dysmorphism,respiratory allergy and gastro-oesophageal reflux all favour the development of OME.Although a certain number of medications(antibiotics,corticoids,antihistamines,mucokinetic agents,and nasal decongestants)can be used to treat OME,they are not reliably effective and rarely provide long-term relief.The benchmark treatment for OME is placement of tympanostomy tubes(TTs)and(in some cases)adjunct adenoidectomy.The TTs rapidly normalize hearing and effectively prevent the development of cholesteatoma in the middle ear.In contrast,TTs do not prevent progression towards tympanic atrophy or a retraction pocket.Adenoidectomy enhances the effectiveness of TTs.In children with adenoid hypertrophy,adenoidectomy is indicated before the age of 4 but can be performed later when OME is identified by nasal endoscopy.Children must be followed up until OME has disappeared completely,so that any complications are not missed. 展开更多
关键词 OTITIS media with EFFUSION Tympanostomy TUBE Ventilation TUBE Grommet CHILD
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Comparison of decompression tubes with metallic stents for the management of right-sided malignant colonic obstruction 预览
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作者 Yoshiyuki Suzuki Konosuke Moritani +2 位作者 Yuki Seo Takayuki Takahashi 《世界胃肠病学杂志:英文版》 SCIE CAS 2019年第16期1975-1985,共11页
BACKGROUND Emergency surgical resection is a standard treatment for right-sided malignant colonic obstruction;however, the procedure is associated with high rates of mortality and morbidity. Although a bridge to surge... BACKGROUND Emergency surgical resection is a standard treatment for right-sided malignant colonic obstruction;however, the procedure is associated with high rates of mortality and morbidity. Although a bridge to surgery can be created to obviate the need for emergency surgery, its effects on long-term outcomes and the most practical management strategies for right-sided malignant colonic obstruction remain unclear. AIM To determine the appropriate management approach for right-sided malignant colonic obstruction. METHODS Forty patients with right-sided malignant colonic obstruction who underwent curative resection from January 2007 to April 2017 were included in the study. We compared the perioperative and long-term outcomes of patients who received bridges to surgery established using decompression tubes and those created using self-expandable metallic stents (SEMS). The primary outcome was the overall survival duration (OS) and the secondary endpoints were the diseasefree survival (DFS) duration and the preoperative and postoperative morbidity rates. Analysis was performed on an intention-to-treat basis. RESULTS There were 21 patients in the decompression tube group and 19 in the SEMS group. There were no significant differences in the perioperative morbidity rates of the two groups. The OS rate was significantly higher in the decompression tube group than in the SEMS group (5-year OS rate;decompression tube 79.5%, SEMS 32%, P = 0.043). Multivariate analysis revealed that the bridge to surgery using a decompression tube was significantly associated with the OS (hazard ratio, 17.41;P = 0.004). The 3-year DFS rate was significantly higher in the decompression tube group than in the SEMS group (68.9% vs 45.9%;log-rank test, P = 0.032). A propensity score–adjusted analysis also demonstrated that the prognosis was significantly better in the decompression tube group than in the SEMS group. CONCLUSION The bridge to surgery using trans-nasal and trans-anal decompression tubes for right-sided malignant colonic obstru 展开更多
关键词 Right-sided colon cancer Large bowel OBSTRUCTION Self-expandable metallic stent Trans-anal TUBE Trans-nasal TUBE
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Experimental investigation on flow characteristics in circular tube inserted with rotor-assembled strand using PIV
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作者 Lichen He Weimin Yang +3 位作者 Changfeng Guan Hua Yan Lin Zheng Xiahua Zuo 《中国化学工程学报:英文版》 SCIE EI CAS CSCD 2019年第1期1-9,共9页
Rotor-assembled strand works as a typical tube insert to achieve heat transfer augmentation and scale inhibition in a heat exchanger.In this work, the PIV experiment regarding the flow fields in a circular tube insert... Rotor-assembled strand works as a typical tube insert to achieve heat transfer augmentation and scale inhibition in a heat exchanger.In this work, the PIV experiment regarding the flow fields in a circular tube inserted with rotor-assembled strand was conducted and the flow characteristics on transverse section and longitudinal section were analyzed.The results showed that swirling flow was produced in the tube inserted with rotors and it was particularly strong within the swing diameter of the rotor on the section that contains the rotor;the average turbulence intensity and the radial velocity were improved notably;the velocity vectors on the longitudinal section remained along the direction of a straight line;both the swirling flow and average turbulence intensity were higher for the rotor with three blades than for the rotor with two blades except that the radial velocity was approximate, but they were all reduced by enlarging the lead of the rotor.Characterization of the flow patterns in a circular tube contributes to understanding the heat transfer efficiency and scale inhibition performance of the rotor-assembled strand and provides guidance for its application. 展开更多
关键词 Particle image VELOCIMETRY (PIV) Swirling flow Rotor-assembled STRAND Circular tube
薄壁与厚壁管材力学性能的统一评价方法——广义缺口环法 预览
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作者 聂光临 包亦望 万德田 《陶瓷学报》 CAS 北大核心 2019年第4期524-529,共6页
管材作为一类重要的材料制品结构形式,其力学性能的准确测试对于保障管材构件服役安全性与可靠性至关重要。目前所提出的缺口环法为测试管材力学性能提供了可行方案,但缺口环法测试管材弹性模量与弯曲强度的计算公式仅适用于薄壁管材。... 管材作为一类重要的材料制品结构形式,其力学性能的准确测试对于保障管材构件服役安全性与可靠性至关重要。目前所提出的缺口环法为测试管材力学性能提供了可行方案,但缺口环法测试管材弹性模量与弯曲强度的计算公式仅适用于薄壁管材。为实现厚壁管材力学性能的准确测试,本研究将径向力与切向力对管材试样的变形能考虑在内,基于曲杆分析理论,提出了适用范围更广的广义缺口环法。以三点弯曲法测得的石英玻璃梁试样弹性模量(72.08±1.87GPa)与弯曲强度(73.84±6.67 MPa)作为参比,分别利用缺口环法与广义缺口环法测得了同一批次石英玻璃管材试样的弹性模量与弯曲强度,测试结果表明:随着管材壁厚的增加,缺口环法测试结果与广义缺口环法测试结果的相对偏差逐渐增大;且广义缺口环法测得的石英玻璃弹性模量和弯曲强度值与三点弯曲法的测试结果更接近,即广义缺口环法的测试结果更准确;同时表明了广义缺口环法既适用于薄壁管材的力学性能测试,也适用于厚壁管材的力学性能测试。 展开更多
关键词 管材 弹性模量 弯曲强度 缺口环法 广义缺口环法
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两辊冷轧纯钛管材的工艺研究
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作者 李永林 王璐 +4 位作者 孟鑫 韩伟松 袁红军 蔡国帅 沈立华 《热加工工艺》 北大核心 2019年第17期42-45,共4页
为了探索两辊冷轧成品管的可行性,本文进行了两种加工率的成品管材轧制。观察了成品管材的显微组织,测试了力学性能,检测了内、外表面质量和尺寸公差。结果表明:TA2纯钛中间管材φ25 mm×1.5 mm分别经64%、76%两辊成品轧制,450℃/40... 为了探索两辊冷轧成品管的可行性,本文进行了两种加工率的成品管材轧制。观察了成品管材的显微组织,测试了力学性能,检测了内、外表面质量和尺寸公差。结果表明:TA2纯钛中间管材φ25 mm×1.5 mm分别经64%、76%两辊成品轧制,450℃/40 min真空退火后的切向显微组织为等轴组织。当两辊冷轧的道次加工率为64%时,两辊成品轧制的管材表面质量光滑、平整,无目视可见的微裂纹;当两辊冷轧的道次加工率增大到76%时,管材外表面出现明显的纵向轧制流线和微裂纹。两辊冷轧TA2成品管材的外径和壁厚公差都非常小,外径的偏差范围为0.03 mm,壁厚的偏差只有0.02 mm。 展开更多
关键词 纯钛 两辊冷轧 管材 工艺
制氢转化炉设计探讨 预览
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作者 满晓伟 《山东化工》 CAS 2019年第18期163-164,166共3页
国内某炼厂制氢转化炉,采用LPEC出口管系专利技术,主要介绍该制氢转化炉的主要工艺参数,入口管系的设计方案及应力分析,转化炉管悬吊系统,出口管系的特点以及对流段的设计方案等,并对转化炉常见的一些问题进行探讨,为更大规模的转化炉... 国内某炼厂制氢转化炉,采用LPEC出口管系专利技术,主要介绍该制氢转化炉的主要工艺参数,入口管系的设计方案及应力分析,转化炉管悬吊系统,出口管系的特点以及对流段的设计方案等,并对转化炉常见的一些问题进行探讨,为更大规模的转化炉设计提供参考。 展开更多
关键词 转化炉 入口管系 转化炉管 出口管系 对流段
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某型飞机肘形导管断裂故障分析与改进验证 预览
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作者 舒送 范鑫 +1 位作者 刘峰 韦顺超 《机床与液压》 北大核心 2019年第2期176-180,共5页
针对某型飞机液压四通管路结构中肘形导管根部多次出现裂纹故障进行研究。根据裂纹位置和断口形貌,确定是由于过大弯曲应力和与平管嘴磨损综合作用下的快速疲劳断裂失效。通过模态分析,发现肘形导管的弯曲模态正好与发动机开车频段重叠... 针对某型飞机液压四通管路结构中肘形导管根部多次出现裂纹故障进行研究。根据裂纹位置和断口形貌,确定是由于过大弯曲应力和与平管嘴磨损综合作用下的快速疲劳断裂失效。通过模态分析,发现肘形导管的弯曲模态正好与发动机开车频段重叠,出现了以横向弯曲为主的共振振型,产生了较大弯曲应力,导致管壁磨损,与故障现象吻合。对此提出了3种改进方案:调整浮动卡箍位置、降低初始安装应力以及减小肘形导管长度。经过仿真分析和综合对比,得到了改进方向。基于应变测量方法,对肘形导管进行了机上发动机开车测试,通过试验数据验证了改进方向的可行性与有效性。 展开更多
关键词 导管 疲劳断裂 模态分析 浮动卡箍
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气管镜引导下经硬质气管镜鞘管放置硅酮支架及T型管治疗良性气管狭窄疗效观察 预览
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作者 李晓 马芸 +3 位作者 张晓菊 马利军 张茜茜 潘金兵 《新乡医学院学报》 CAS 2019年第2期143-146,共4页
目的探讨气管镜引导下经硬质气管镜鞘管放置硅酮支架及T型管治疗良性气管狭窄的临床疗效。方法选取河南省人民医院2015年9月至2016年10月收治的10例气管狭窄患者为研究对象。根据患者气管狭窄性质、程度及解剖结构,选取合适的硅酮支架及... 目的探讨气管镜引导下经硬质气管镜鞘管放置硅酮支架及T型管治疗良性气管狭窄的临床疗效。方法选取河南省人民医院2015年9月至2016年10月收治的10例气管狭窄患者为研究对象。根据患者气管狭窄性质、程度及解剖结构,选取合适的硅酮支架及T型管,在电子支气管镜引导下插入硬质支气管鞘管,并进行支架及T型管置入。术后60d内行气管镜动态监测支架位置及气管内分泌物、肉芽组织生长等情况;术前和术后30d行血气分析,并采用卡氏(KPS)评分对患者生活质量进行评估。结果6例患者置入硅酮支架,4例患者置入T型管。硅酮支架及T型管均一次性置入成功,10例患者置入硅酮支架或T型管后呼吸困难症状均即刻缓解。10例患者术后30d氧分压和KPS评分均高于术前(t=-10.585、-15.476,P<0.05)。术后60d内支气管镜下观察,3例患者轻度气管内肉芽组织增生,2例支架移位,2例排痰困难,对症处理后好转。结论气管镜引导下经硬质气管镜鞘管放置硅酮支架及T型管治疗良性气管狭窄技术可行,操作安全,疗效可靠。 展开更多
关键词 硅酮支架 T型管 气管狭窄 硬质支气管镜
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窄间隙焊接工艺在电站锅炉小口径管制造中的应用 预览
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作者 王萍 陈肈宇 《锅炉制造》 2019年第1期43-44,共2页
本文介绍了窄间隙焊接工艺在电站锅炉小口径管制造中的应用,阐述了窄间隙坡口的加工要求、窄间隙热丝TIG焊的参数设定、窄间隙手工氩弧焊的操作要点及窄间隙坡口焊接接头在力学性能方面的优势等。
关键词 窄间隙焊接工艺 小口径管 锅炉
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经T管腔内胆道支架治疗胆道探查术后胆汁漏1例报道并文献复习
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作者 冯渊 杨均均 +1 位作者 杨红春 彭勇 《中国普外基础与临床杂志》 CAS 2019年第6期719-722,共4页
目的探讨经T管腔内行胆道支架置入和肝内胆管置入鼻胆管胆道引流治疗胆道探查术后胆汁漏的临床疗效。方法回顾性分析南充市中心医院肝胆外科于2016年12月收治的1例胆总管探查术后胆汁漏患者的临床资料。结果对该例患者采用经T管腔内置... 目的探讨经T管腔内行胆道支架置入和肝内胆管置入鼻胆管胆道引流治疗胆道探查术后胆汁漏的临床疗效。方法回顾性分析南充市中心医院肝胆外科于2016年12月收治的1例胆总管探查术后胆汁漏患者的临床资料。结果对该例患者采用经T管腔内置入胆道支架和肝内胆管置入鼻胆管行胆道引流。经T管腔内隧道插入导丝至肝门部,向肝门部置入鼻胆管引流;另经T管再置入导丝1根,进入十二指肠,向十二指肠内置入8.5F塑料支架1根,支架一端置于胆总管内,一端于肠腔内,行胆道引流。引流术后患者胆汁漏停止,腹腔感染得到控制,于胆道支架置入术后10d顺利出院,术后20d夹闭T管和鼻胆管,2个月后行T管造影和腹部B超发现胆总管下段支架已脱落,拔除T管。门诊随访2年,患者完全康复。结论经T管腔内行胆总管下段支架置入术和肝门鼻胆管引流术是治疗胆汁漏的有效方法之一,方法简单,易于操作。 展开更多
关键词 胆汁漏 胆道探查 T管 胆道支架
Investigation on Precooling Effects of 4 K Stirling-Type Pulse Tube Cryocoolers
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作者 CAO Qiang LI Zimu +5 位作者 LUAN Mingkai SUN Zheng TANG Xiao LI Peng JIANG Zhenhua WEI Li 《热科学学报:英文版》 SCIE EI CAS CSCD 2019年第4期714-726,共13页
Stirling-type pulse tube cryocoolers(SPTCs)working at liquid-helium temperatures are appealing in space applications because of their promising advantages such as high reliability,compactness,etc.Worldwide efforts hav... Stirling-type pulse tube cryocoolers(SPTCs)working at liquid-helium temperatures are appealing in space applications because of their promising advantages such as high reliability,compactness,etc.Worldwide efforts have been put in to develop SPTCs operating at liquid-helium temperatures especially with helium-4 as the working fluid.Staged structure is essential to reach such low temperatures.Generally,both the regenerator of the last section and the pulse tube together with the phase shifter are precooled by its upper stage or by external cold source to a low temperature of around 20 K.However,the precooling effects on the regenerator and the pulse tube are synthetic in previous studies,and their independent effects have not been studied clearly.In this manuscript,the precooling effects on the regenerator and on the pulse tube together with the phase shifter are tested independently on a unique-designed precooled SPTC.The tested precooling temperature is between 13.3 K and 22 K,and the no-load refrigeration temperature gets down to 3.6 K.Further analyses and numerical calculations have been carried out.It is found that the influence on the regenerator is remarkable,which is different from previous conclusions.It is also found that the precooling effects on the pulse tube are relatively weak because of the large pressure-induced enthalpy flow of a real gas working at the temperatures near to the critical point.Furthermore,the phase shifting capacity is analyzed with two cases and with both helium-4 and helium-3 as working fluids,and it keeps quite constant after optimizing the frequency and the precooling temperature for each case.The investigation on these independent effects will provide valid reference on the precooling mechanism study of SPTCs working down to liquid-helium temperatures. 展开更多
关键词 stirling-type PULSE tube CRYOCOOLER precooling effects liquid-helium TEMPERATURES
Study on Vulnerability of Concrete Filled Steel Tube Frame-Buckling- Resistant Bracing Structure System under Wind and Earthquake Coupling 预览
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作者 Yongjun Xu 《智能建筑研究》 2019年第1期106-118,共13页
Engineering structures will inevitably be affected by various disasters such as wind or earthquake during their whole service life. Taking the concrete-filled steel tube frame-buckling-restrained brace structure syste... Engineering structures will inevitably be affected by various disasters such as wind or earthquake during their whole service life. Taking the concrete-filled steel tube frame-buckling-restrained brace structure system as the research object, the wind speed time histories at different heights of the structure with recurrence periods of 1 year, 10 years and 50 years are simulated. Based on the OpenSees finite element software, the nonlinear dynamic time history analysis of the structure under four working conditions of earthquake single action and wind-earthquake coupling action with recurrence periods of 1 year, 10 years and 50 years respectively is carried out, and the vulnerability curves of the structure under different working conditions are generated based on the seismic demand analysis method. The results show that with the increase of wind action, the structural response and vulnerability have an increasing trend. However, with the increase of ground motion intensity, the influence of wind on structural vulnerability gradually decreases. 展开更多
关键词 COUPLING effect of WIND and EARTHQUAKE Concrete filled steel tube FRAME Buckling prevention support Non linear dynamic time history analysis: VULNERABILITY
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Experimental study of large-amplitude standing-wave field obtained in a standing-wave tube with uniform cross section
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作者 MIN Qi HE Wanquan +2 位作者 WANG Quanbiao GE Shuping WANG Shengyu 《声学学报:英文版》 CSCD 2019年第3期353-368,共16页
A large-amplitude standing-wave field of 182.1 dB is obtained under the excitation at the resonant frequency of the lst-order peak of the sound pressure transfer function in an improved standing-wave tube experimental... A large-amplitude standing-wave field of 182.1 dB is obtained under the excitation at the resonant frequency of the lst-order peak of the sound pressure transfer function in an improved standing-wave tube experimental system,and saturation of harmonics and waveform distortion are investigated experimentally for the large-amplitude standing-wave fields obtained under the excitations at the resonant frequencies of the 1 st-to the 5 th-order peaks.The results show that although the sound pressure level has reached 182.1 dB under the excitation at the resonant frequency of the 1 st-order peak,the waveform distortion is the minimum and the harmonic saturation is not observed.However,the large-amplitude standing-wave field excited at the resonant frequency of the 3 rd-order peak exhibits the trend of the harmonic saturation.Comparison of the large-amplitude standing-wave fields obtained under the excitations at valley resonant frequencies shows that the standing-wave field excited at the resonant frequency of the 1 st-order valley has the largest SPL,but also has the largest waveform distortion.Under the same source-driving voltage,the standing-wave field excited at the resonant frequency of the 1 st-order peak always has greater SPL than the standing-wave field excited at the resonant frequency of the 1 st-order valley.Hence,to obtain a large-amplitude standing-wave field,it’s better to excite at the resonant frequency of the 1 st-order peak of the SPTF by using loudspeaker in a standing-wave tube with uniform cross section. 展开更多
关键词 domain SPL Experimental study of LARGE-AMPLITUDE STANDING-WAVE field obtained in a STANDING-WAVE TUBE with UNIFORM cross section
Response features of nonlinear circumferential guided wave on early damage in inner layer of a composite circular tube
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作者 李明亮 刘良兵 +4 位作者 高广健 邓明晰 胡宁 项延训 朱武军 《中国物理B:英文版》 SCIE EI CAS CSCD 2019年第4期224-229,共6页
A theoretical model to analyze the nonlinear circumferential guided wave(CGW) propagation in a composite circular tube(CCT) is established. The response features of nonlinear CGWs to early damage [denoted by variation... A theoretical model to analyze the nonlinear circumferential guided wave(CGW) propagation in a composite circular tube(CCT) is established. The response features of nonlinear CGWs to early damage [denoted by variations in third-order elastic constants(TOECs)] in an inner layer of CCT are investigated. On the basis of the modal expansion approach, the second-harmonic field of primary CGW propagation can be assumed to be a linear sum of a series of double-frequency CGW(DFCGW) modes. The quantitative relationship of DFCGW mode versus the relative changes in the inner layer TOECs is then investigated. It is found that the changes in the inner layer TOECs of CCT will obviously affect the driving source of DFCGW mode and its modal expansion coefficient, which is intrinsically able to influence the efficiency of cumulative second-harmonic generation(SHG) by primary CGW propagation. Theoretical analyses and numerical simulations demonstrate that the second harmonic of primary CGW is monotonic and very sensitive to the changes in the inner layer TOECs of CCT, while the linear properties of primary CGW propagation almost remain unchanged. Our results provide a potential application for accurately characterizing the level of early damage in the inner layer of CCT through the efficiency of cumulative SHG by primary CGW propagation. 展开更多
关键词 CIRCUMFERENTIAL GUIDED wave(CGW) early damage INNER LAYER of COMPOSITE circular tube secondharmonic generation(SHG)
Optimal timing and route of nutritional support after esophagectomy:A review of the literature 预览
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作者 Richard Zheng Courtney L Devin +3 位作者 Michael J Pucci Adam C Berger Ernest L Rosato Francesco Palazzo 《世界胃肠病学杂志:英文版》 SCIE CAS 2019年第31期4427-4436,共10页
Some controversy surrounds the postoperative feeding regimen utilized in patients who undergo esophagectomy.Variation in practices during the perioperative period exists including the type of nutrition started,the del... Some controversy surrounds the postoperative feeding regimen utilized in patients who undergo esophagectomy.Variation in practices during the perioperative period exists including the type of nutrition started,the delivery route,and its timing.Adequate nutrition is essential for this patient population as these patients often present with weight loss and have altered eating patterns after surgery,which can affect their ability to regain or maintain weight.Methods of feeding after an esophagectomy include total parenteral nutrition,nasoduodenal/nasojejunal tube feeding,jejunostomy tube feeding,and oral feeding.Recent evidence suggests that early oral feeding is associated with shorter LOS,faster return of bowel function,and improved quality of life.Enhanced recovery pathways after surgery pathways after esophagectomy with a component of early oral feeding also seem to be safe,feasible,and cost-effective,albeit with limited data.However,data on anastomotic leaks is mixed,and some studies suggest that the incidence of leaks may be higher with early oral feeding.This risk of anastomotic leak with early feeding may be heavily modulated by surgical approach.No definitive data is currently available to definitively answer this question,and further studies should look at how these early feeding regimens vary by surgical technique.This review aims to discuss the existing literature on the optimal route and timing of feeding after esophagectomy. 展开更多
关键词 ESOPHAGECTOMY Oral FEEDING Early FEEDING Delayed FEEDING ENTERAL nutrition Esophageal cancer JEJUNOSTOMY tube POSTOPERATIVE COMPLICATIONS
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Caval replacement with parietal peritoneum tube graft for septic thrombophlebitis after hepatectomy: A case report 预览
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作者 Charlotte Maulat Léopoldine Lapierre +3 位作者 Isabelle Migueres Xavier Chaufour Guillaume Martin-Blondel Fabrice Muscari 《世界肝病学杂志:英文版(电子版)》 2019年第1期133-137,共5页
BACKGROUND Caval vein thrombosis after hepatectomy is rare, although it increases mortality and morbidity. The evolution of this thrombosis into a septic thrombophlebitis responsible for persistent septicaemia after a... BACKGROUND Caval vein thrombosis after hepatectomy is rare, although it increases mortality and morbidity. The evolution of this thrombosis into a septic thrombophlebitis responsible for persistent septicaemia after a hepatectomy has not been reported to date in the literature. We here report the management of a 54-year-old woman operated for a peripheral cholangiocarcinoma who developed a suppurated thrombophlebitis of the vena cava following a hepatectomy. CASE SUMMARY This patient was operated by left lobectomy extended to segment V with bile duct resection and Roux-en-Y hepaticojejunostomy. After the surgery, she developed Streptococcus anginosus, Escherichia coli, and Enterococcus faecium bacteraemias, as well as Candida albicans fungemia. A computed tomography scan revealed a bilioma which was percutaneously drained. Despite adequate antibiotic therapy, the patient’s condition remained septic. A diagnosis of septic thrombophlebitis of the vena cava was made on post-operative day 25. The patient was then operated again for a surgical thrombectomy and complete caval reconstruction with a parietal peritoneum tube graft. Use of the peritoneum as a vascular graft is an inexpensive technique, it is readily and rapidly available, and it allows caval replacement in a septic area. Septic thrombophlebitis of the vena cava after hepatectomy has not been described previously and it warrants being added to the spectrum of potential complications of this procedure.CONCLUSION Septic thrombophlebitis of the vena cava was successfully treated with antibiotic and anticoagulation treatments, prompt surgical thrombectomy and caval reconstruction. 展开更多
关键词 Bilioma SEPTIC thrombophlebitis SEPTICAEMIA PARIETAL PERITONEUM TUBE GRAFT Complete caval reconstruction Case report
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Utilizing vector hydrophones to achieve an active anechoic terminal in an acoustic tube
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作者 WANG Xiaolin LIU Bilong +2 位作者 YANG Jun LIU Jingwei WANG Ran 《声学学报:英文版》 CSCD 2019年第2期201-214,共14页
A new integrated active sound absorptive terminal using vector hydrophones is developed for the anechoic terminal of impedance tube,with which the reflected and the incident waves can be separated.The method overcomes... A new integrated active sound absorptive terminal using vector hydrophones is developed for the anechoic terminal of impedance tube,with which the reflected and the incident waves can be separated.The method overcomes the limitations imposed by the sensor spacing and measuring frequency range in the traditional two-hydrophone method,and can effectively expand low-frequency sound absorption band of the terminal.The effect of hydrophone sensitivity on the sound absorptive performance of the terminal is evaluated,a correction method is also provided for the reflection and transmission coefficient.The experimental results show that the absorption coefficient in the frequency band of 0.1-2 kHz is over 0.98,which agrees well with the theoretical results. 展开更多
关键词 Utilizing VECTOR HYDROPHONES ACOUSTIC TUBE
CFD–DEM simulation of fine particles in a spouted bed apparatus with a Wurster tube
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作者 Paul Breuninger Dominik Weis +3 位作者 Isabell Behrendt Philipp Grohn Fabian Krull Sergiy Antonyuk 《中国颗粒学报:英文版》 SCIE EI CAS CSCD 2019年第1期114-125,共12页
In this work, a coupled computational fluid dynamics–discrete element method (CFD–DEM) approach was employed to evaluate the spouting behavior of fine, cohesive powders in a cylindrical spouted bed with a conical ba... In this work, a coupled computational fluid dynamics–discrete element method (CFD–DEM) approach was employed to evaluate the spouting behavior of fine, cohesive powders in a cylindrical spouted bed with a conical base and equipped with a Wurster tube. The particle and gas dynamics inside the apparatus were simulated with 1.7 million spherical ZrO2 particles with a particle size of 100 μm. For an accurate prediction of the interactions of cohesive particles in the spouted bed, the adhesion forces according to JKR theory were included in the Hertz–Tsuji contact model. The surface energy of the particles was varied over a wide range to determine the effect of the adhesion on the spouting (the fountain shape and maximum height as well as the distribution of the concentrations and velocities of particles in different zones of the apparatus). A detailed analysis of the collision dynamics was conducted. The spouting behavior of a spouted bed with the same dimensions, particles, and processing parameters was recorded with a high-speed camera. The CFD–DEM simulations showed good agreement with the experimentally captured spouting behavior. 展开更多
关键词 CFD–DEM Spouted BED Wurster TUBE COHESIVE POWDER
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