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超声波气升式反应器内声压的测定 被引量:2
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作者 汤立新 吕效平 《化学工业与工程技术》 CAS 2002年第6期24-26,共3页
测定了在空气—水和空气—羧甲基纤维素水溶液体系中 (羧甲基纤维素含量 :2g/L)超声波气升式反应器声压随轴向位置、表观气速、黏度和超声电功率的变化。测定结果表明 ,小气速下声压在气升式反应器内的轴向分布与离开超声探头的距离有... 测定了在空气—水和空气—羧甲基纤维素水溶液体系中 (羧甲基纤维素含量 :2g/L)超声波气升式反应器声压随轴向位置、表观气速、黏度和超声电功率的变化。测定结果表明 ,小气速下声压在气升式反应器内的轴向分布与离开超声探头的距离有关 ,距离越远 ,声压越小 ;与气速的大小有关 ,气速越大 ,声压越小 ;与液体的黏度有关 ,黏度越大 ,声压越小 ;超声电功率越大 ,声压越大。 展开更多
关键词 波气升式反应器 内声压 测定 轴向位置
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模态及尺寸参数对封闭腔内声压的影响研究
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作者 董红亮 高书娜 《西南大学学报(自然科学版)》 CAS CSCD 北大核心 2021年第2期138-145,共8页
为掌握影响车内低频声压的关键参数及其影响规律,以快速有效控制车内低频噪声,基于封闭腔内声压的计算公式,对模态参数、尺寸参数与声压响应的关系进行了分析.首先获得腔内声压可直接用公式计算的研究对象和计算公式;其次通过分析公式... 为掌握影响车内低频声压的关键参数及其影响规律,以快速有效控制车内低频噪声,基于封闭腔内声压的计算公式,对模态参数、尺寸参数与声压响应的关系进行了分析.首先获得腔内声压可直接用公式计算的研究对象和计算公式;其次通过分析公式中的可变输入量,找出影响腔内声压的主要模态参数、尺寸参数,采用仅改变某一参数而保持其余参数为初始值的方法,逐个计算分析这些参数对腔内声压的影响规律,找出影响腔内声压的关键参数及其影响规律,并通过试验进行了验证;最后利用关键参数及其影响规律对某型轿车的车内低频噪声进行控制,快速、成功将其车内低频声压降低到目标范围内.研究结果表明:腔内声压的关键参数是结构振型的节线数、结构板厚;增加1条节线,即结构增加1个“+”加强筋或加强梁,或增加结构板厚,可降低腔内声压;以此研究结论为指导,在某型轿车的车身薄弱位置添加加强筋后,原超出目标范围的峰值声压降低了约10 dB,快速降低到目标范围以内,从而为车内低频噪声的快速控制提供一条新思路. 展开更多
关键词 车辆工程 封闭腔内声压 模态参数 尺寸参数 节线数 结构板厚
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ANALYSIS OF INTERNAL WAVERIDER INLET AND TYPICAL SIDEWALL COMPRESSION INLET PERFORMANCE 被引量:4
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作者 黄国平 朱呈祥 +1 位作者 尤延铖 周淼 《Transactions of Nanjing University of Aeronautics and Astronautics》 EI 2011年第1期120-128,共9页
A new internal waverider inlet with a rectangular shape of entrance and exit in front view is designed at Ma=6.0.The design is based on a better basic flowfield ICFC than traditional one and derived with the technolog... A new internal waverider inlet with a rectangular shape of entrance and exit in front view is designed at Ma=6.0.The design is based on a better basic flowfield ICFC than traditional one and derived with the technology of stream tracing and shock cutting.Comparison between the newly designed inlet and a typical sidewall compression inlet is given.The design Mach number and entrance shape of this new inlet are chosen according to the sidewall compression inlet.Numerical results show that most of the performance parameters of the internal waverider inlet are a bit higher than the sidewall inlet,such as the flow capture coefficient,total pressure recovery and the kinetic efficiency.The performances of these two inlets at off-design points are compared.The internal waverider inlet can capture more than 91% of incoming flow under all simulated conditions.Results show that internal waverider inlet using 3-D compression and high flow capture coefficient is a kind of fixed-geometry inlet with better performance. 展开更多
关键词 HYPERSONIC PERFORMANCE internal waverider inlet sidewall compression inlet
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Referral for anorectal function evaluation is indicated in 65% and beneficial in 92% of patients
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作者 Maria M Szojda Erik Tanis +1 位作者 Chris JJ Mulder Richelle JF Felt-Bersma 《World Journal of Gastroenterology》 SCIE CAS CSCD 2008年第2期272-277,共6页
AIM: To determine the indicated referrals to a tertiary centre for patients with anorectal symptoms, the effect of the advised treatment and the discomfort of the tests.METHODS: In a retrospective study, patients refe... AIM: To determine the indicated referrals to a tertiary centre for patients with anorectal symptoms, the effect of the advised treatment and the discomfort of the tests.METHODS: In a retrospective study, patients referred for anorectal function evaluation (AFE) between May 2004 and October 2006 were sent a questionnaire, as were the doctors who referred them. AFE consisted of anal manometry, rectal compliance measurement and anal endosonography. An indicated referral was defined as needing AFE to establish a diagnosis with clinical consequence (fecal incontinence without diarrhea, 3rd degree anal sphincter rupture, congenital anorectal disorder, inflammatory bowel disease with anorectal complaints and preoperative in patients for re-anastomosis or enterostoma, anal fissure, fistula or constipation). Anal ultrasound is always indicated in patients with fistula, anal manometry and rectal compliance when impaired continence reserve is suspected. The therapeutic effect was noted as improvement, no improvement but reassurance, and deterioration.RESULTS: From the 216 patients referred, 167 (78%) returned the questionnaire. The referrals were indicated in 65%. Of these, 80% followed the proposed advice. Improvement was achieved in 35% and a reassurance in 57% of the patients, no difference existed between patient groups. On a VAS scale (1 to 10) symptoms improved from 4.0 to 7.2. Most patients reported no or little discomfort with AFE. CONCLUSION: Referral for AFE was indicated in 65%. Beneficial effect was seen in 92%: 35% improved and 57% was reassured. Advice was followed in 80%. Better instruction about indication for AFE referral is warranted. 展开更多
关键词 Anorectal function evaluation Fecal incontinence Anal endosonography Anal manometry
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