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某混动皮卡进气空滤的辐射噪声分析及结构优化
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作者 金栋 申一方 《汽车实用技术》 2023年第24期115-120,共6页
进气声压导致空滤壳体振动,从而产生辐射噪声,因此,可以通过优化空滤的结构来抑制辐射噪声。一辆混动皮卡车在试验过程中发现,发动机在2000 r/min时车内存在明显轰鸣声。针对该轰鸣声进行排查,发现进气系统空滤壳体辐射噪声大是主要贡... 进气声压导致空滤壳体振动,从而产生辐射噪声,因此,可以通过优化空滤的结构来抑制辐射噪声。一辆混动皮卡车在试验过程中发现,发动机在2000 r/min时车内存在明显轰鸣声。针对该轰鸣声进行排查,发现进气系统空滤壳体辐射噪声大是主要贡献源。为解决该问题,首先进行空滤模态分析和进气声压谱计算,结果表明,进气系统声压激励与空滤壳体面板的模态频率耦合共振,导致车辆噪声增加;其次,通过对空滤上壳体的拓扑优化,找出了加强筋的最佳布置位置,使空滤上壳体模态频率得到大幅提高,避开了声压激励频谱最大值的频率,消除共振;再次,通过辐射噪声的计算,确认了优化后的空滤上壳体的总声功率级降低了8 dB(A),噪声改进效果非常明显;最后,通过实车验证,证明该研究方法可以有效地解决此类似问题。 展开更多
关键词 混动皮卡 学响应 气空滤 形貌优化 辐射噪
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发动机进气消声元件设计与声学数值模拟的研究 被引量:6
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作者 陈达亮 顾灿松 +1 位作者 王务林 李洪亮 《汽车工程》 EI CSCD 北大核心 2011年第3期246-249,261,共5页
提出了以声压级差值作为评价发动机进气系统消声性能的指标,并应选择入射声波声压级进行计算,同时施加全吸声截面声阻抗,以反映进气系统真实的声学特性。考虑到开口端的影响,给出了谐振腔和1/4波长管共振频率理论计算的修正公式,使计算... 提出了以声压级差值作为评价发动机进气系统消声性能的指标,并应选择入射声波声压级进行计算,同时施加全吸声截面声阻抗,以反映进气系统真实的声学特性。考虑到开口端的影响,给出了谐振腔和1/4波长管共振频率理论计算的修正公式,使计算误差降至2%以内。最后对消声元件安装位置的选择进行了相关研究。 展开更多
关键词 发动机 气消元件 谐振腔 共振频率
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国内第一个压气机进气消声实验室在北京航空航天大学建成 被引量:2
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作者 王同庆 鲍国良 史伟 《航空动力学报》 EI CAS CSCD 北大核心 2003年第4期574-576,共3页
介绍了北航压气机进气消声实验室的性能,以及建成后进行的实验,并与国外同类实验室进行了对比。
关键词 北京航空航天大学 压气机 气消 实验室 航空发动机
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发动机进气歧管对进气系统声品质的影响 被引量:1
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作者 王若平 洪森 《重庆理工大学学报(自然科学)》 CAS 北大核心 2018年第5期27-31,共5页
发动机进气系统是动力总成的关键组成部分,其声品质对动力总成的声品质具有重要的影响。进气歧管的结构对调节进气系统的声品质具有至关重要的作用。利用GEM-3D软件和GT-POWER软件相结合,对某直列四缸汽油机进行了仿真,采集了虚拟发动... 发动机进气系统是动力总成的关键组成部分,其声品质对动力总成的声品质具有重要的影响。进气歧管的结构对调节进气系统的声品质具有至关重要的作用。利用GEM-3D软件和GT-POWER软件相结合,对某直列四缸汽油机进行了仿真,采集了虚拟发动机进气噪声,通过GT-POST对2种不同进气歧管所形成的发动机进气噪声的声品质进行分析,总结出一般规律:中心进气歧管的发动机进气噪声听觉舒适感更佳,旁支进气歧管的发动机进气噪声听觉运动感更强。为发动机进气系统的设计与开发提供了理论支持。 展开更多
关键词 气歧管 气系统品质 GT-POWER
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基于正交试验的进气消声元件优化设计
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作者 程市 钱叶剑 罗琳 《内燃机与动力装置》 2015年第6期60-65,共6页
论文分析了进气噪声的产生机理,针对原机各阶次噪声出现的噪声尖点,找出了对应的振动频率。利用正交试验对空滤器的扩张比(容积恒定)、Helmholtz谐振腔和1/4波长管消声元件的结构参数进行综合优化设计,最大限度降低进气噪声。结果表明:... 论文分析了进气噪声的产生机理,针对原机各阶次噪声出现的噪声尖点,找出了对应的振动频率。利用正交试验对空滤器的扩张比(容积恒定)、Helmholtz谐振腔和1/4波长管消声元件的结构参数进行综合优化设计,最大限度降低进气噪声。结果表明:基于正交试验得到的消声元件组合方案的进气插入损失最大(61.45d B),各阶次噪声均在阶次噪声限值以下,提升了进气消声系统的开发效率。 展开更多
关键词 气消元件 阶次噪 插入损失 正交试验
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智能型非接触超声浓度计的研制 被引量:1
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作者 高德群 《仪器仪表用户》 2016年第9期1-4,17,共5页
本文介绍一种通用型超声波浓度计,通过浓度、温度、声时三者的相互关系来进行溶液浓度测量。通过实验,精确地测定多种溶液在不同温度、不同浓度时的声速,给出相应的浓度。
关键词 非接触超波浓度计 温度 声进
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汽车空气滤清器声学性能数值计算及分析 被引量:19
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作者 朱廉洁 季振林 《噪声与振动控制》 CSCD 北大核心 2007年第2期55-58,共4页
发动机进气系统设计除了满足进气和空气滤清要求外,通常还要求能够有效地降低进气噪声。设计消声效果良好的空气滤清器是控制发动机进气噪声的有效措施之一。由于一维平面波理论只适于低频分析,为了扩大分析的频率范围,采用了三维有限... 发动机进气系统设计除了满足进气和空气滤清要求外,通常还要求能够有效地降低进气噪声。设计消声效果良好的空气滤清器是控制发动机进气噪声的有效措施之一。由于一维平面波理论只适于低频分析,为了扩大分析的频率范围,采用了三维有限元数值方法分析空气滤清器的声学特性。同时,空气滤清器中的滤纸大多是纤维材料,可以作为吸声材料来处理,所以在考虑滤纸的情况下分析空气滤清器的消声性能,其中以纤维吸声材料的经验公式来模拟滤纸的声学特性。通过比较不带滤纸和带有滤纸的空气滤清器的声学性能结果表明,滤纸的考虑与否对空滤器的中高频消声性能有很大影响。 展开更多
关键词 空气滤清器 气消 滤纸 有限元分析
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浅谈城市综合体冷却塔消声降噪深化设计及施工工艺 被引量:2
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作者 曾勇 邓国良 《中国住宅设施》 2011年第10期55-58,共4页
针对城市建筑趋于空间高度发展和集住宅、办公、酒店及商场综合性发展,现城市综合体的招标基本按照方案招标,施工单位需要自己进行深化设计及施工;此外城市综合体集中的特性对噪音控制要求高,因此空调系统冷却塔设置及消声降噪问题突出... 针对城市建筑趋于空间高度发展和集住宅、办公、酒店及商场综合性发展,现城市综合体的招标基本按照方案招标,施工单位需要自己进行深化设计及施工;此外城市综合体集中的特性对噪音控制要求高,因此空调系统冷却塔设置及消声降噪问题突出。本文主要对城市综合体冷却塔消声降噪设计及施工工艺进行总结,以便后续类似城市综合体冷却塔深化设计及施工给各建筑施工企业技术人员及深化设计人员进行参考。 展开更多
关键词 城市综合体 深化设计 排风消装置 内外风消装置 屏障 阻力计算 学计算 施工工艺
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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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Principle and Analysis of Novel Gate-Induced Noise in Pixel MOSFET of CMOS Imagers
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作者 金湘亮 陈杰 仇玉林 《Journal of Semiconductors》 EI CAS CSCD 北大核心 2003年第9期921-926,共6页
A detailed principle and a rigorous analysis of a new noise,the gate-induced noise,in pixel MOSFET of CMOS imagers are provided.The gate-induced noise of the MOSFET is more notable in the strong reversion region than... A detailed principle and a rigorous analysis of a new noise,the gate-induced noise,in pixel MOSFET of CMOS imagers are provided.The gate-induced noise of the MOSFET is more notable in the strong reversion region than that in the subthreshold region when the applied gate voltage is low.However,the applied gate voltage being up to 3V,the gate-induced noise is more notable with the ω/ω T increasing when the MOSFET operates in the subthreshold region than that in the strong reversion region.Between the photocurrent I D and the root mean square value of the gated-induced noise,current i 2 d presents the relation of i 2 d∝I D in the saturation region of the strong reversion and approximately i 2 d∝I D in the subthreshold region.A deta iled and rigorous study of the gate-induced noise in the reset MOSFET for the p hotodiode APS and improved photodiode APS are provided.The improvement of logari thmic response APS is analyzed and the simulation results show that the gate-in duced noise can be reduced. 展开更多
关键词 gate-induced noise pixel MOSFET improved photodiode APS CMOS imagers
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进气歧管对汽车进气声品质影响研究 被引量:1
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作者 周晓杰 刘志恩 +1 位作者 颜伏伍 杜松泽 《数字制造科学》 2019年第1期6-10,16,共6页
针对提升车辆的运动感,即提高进气半阶次噪声的问题,以某款4缸发动机的等长进气歧管为研究对象,改变间隔发火缸的歧管长度,研究整阶次及半阶次噪声的变化规律;改变等长进气歧管的管长,研究进气管口及整阶次噪声的变化规律。得出了进气... 针对提升车辆的运动感,即提高进气半阶次噪声的问题,以某款4缸发动机的等长进气歧管为研究对象,改变间隔发火缸的歧管长度,研究整阶次及半阶次噪声的变化规律;改变等长进气歧管的管长,研究进气管口及整阶次噪声的变化规律。得出了进气歧管间隔发火缸的歧管长度相差越大,进气半阶次噪声越大和通过改变等长进气歧管的歧管长度可以增加或减少某些特定频率噪声的结论。以此为依据,正向设计一款进气歧管,使进气半阶次噪声较原方案整体提高,进而改善进气声品质。最后设计声学试验进行验证。 展开更多
关键词 气歧管 半阶次 品质
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Constructing Non-binary Asymmetric Quantum Codes via Graphs 被引量:2
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作者 马智 冷日光 +1 位作者 魏正超 钟淑琴 《China Communications》 SCIE CSCD 2013年第2期33-41,共9页
The theory of quantum error correcting codes is a primary tool for fighting decoherence and other quantum noise in quantum communication and quantum computation. Recently, the theory of quantum error correcting codes ... The theory of quantum error correcting codes is a primary tool for fighting decoherence and other quantum noise in quantum communication and quantum computation. Recently, the theory of quantum error correcting codes has developed rapidly and been extended to protect quantum information over asymmetric quantum channels, in which phase-shift and qubit-flip errors occur with different probabilities. In this paper, we generalize the construction of symmetric quantum codes via graphs (or matrices) to the asymmetric case, converting the construction of asymmetric quantum codes to finding matrices with some special properties. We also propose some asymmetric quantum Maximal Distance Separable (MDS) codes as examples constructed in this way. 展开更多
关键词 asymmetric quantum codes quantum MDS codes graph construction
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Evolutionary Game Dynamics in a Fitness-Dependent Wright-Fisher Process with Noise 被引量:3
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作者 全吉 王先甲 《Communications in Theoretical Physics》 SCIE CAS CSCD 2011年第9期404-410,共7页
Evolutionary game dynamics in finite size populations can be described by a fitness-dependent Wright- Fisher process. We consider symmetric 2×2 games in a well-mixed population. In our model, two parameters to de... Evolutionary game dynamics in finite size populations can be described by a fitness-dependent Wright- Fisher process. We consider symmetric 2×2 games in a well-mixed population. In our model, two parameters to describe the level of player's rationality and noise intensity in environment are introduced. In contrast with the fixation probability method that used in a noiseless case, the introducing of the noise intensity parameter makes the process an ergodic Markov process and based on the limit distribution of the process, we can analysis the evolutionary stable strategy (ESS) of the games. We illustrate the effects of the two parameters on the ESS of games using the Prisoner's dilemma games (PDG) and the snowdrift games (SG). We also compare the ESS of our model with that of the replicator dynamics in infinite size populations. The results are determined by simulation experiments. 展开更多
关键词 evolutionary games Wright-Fisher process evolutionary stable strategy noise
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Numerical Investigation of an Active Jet Control Method for Hypersonic Inlet Restart
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作者 JIN Yichao YAO Wei 《Transactions of Nanjing University of Aeronautics and Astronautics》 EI CSCD 2022年第6期651-662,共12页
A flow control method based on an active jet is developed to restart hypersonic inlets. The dynamic restarting process is numerically reproduced by unsteady Reynolds averaged Navier-Stokes(RANS) modeling to verify the... A flow control method based on an active jet is developed to restart hypersonic inlets. The dynamic restarting process is numerically reproduced by unsteady Reynolds averaged Navier-Stokes(RANS) modeling to verify the effectiveness and reveal the influence of jet conditions. The active jet improves the inlet unstart status by drawing the high-pressure separation bubble from the internal compression duct and performing a full expansion to alleviate the adverse pressure gradient. Moreover, the favorable pressure gradient in the inlet caused by jet expansion allows for a successful restart after turning off the jet. The influence of the jet momentum ratio is then analyzed to guide the design of the active jet control method and choose the proper momentum ratios. A low jet momentum does not eliminate the high-pressure separation bubble, whereas an excessive jet momentum causes severe momentum loss due to the induced shock. The general rule in restarting the inlet using an active jet is to allow a full jet expansion downstream of the jet slot while avoiding excessive momentum loss upstream and preventing the thick low-speed layer. 展开更多
关键词 hypersonic inlet UNSTART RESTART active jet flow control
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Optimization of Sonication Process for High Newcastle Disease Virus (NDV) Titer
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作者 Jaafar Nuhu Ja'afar Maizirwan Mel +2 位作者 Mohd. Ismail Abdul Karim Aini Ideris Sharifah Syed Hassan 《Journal of Chemistry and Chemical Engineering》 2010年第4期49-54,共6页
Cell disruption focuses on obtaining a desired bioproduct within a cell, and it is the cell wall that must be disrupted to allow access to the contents of the cell. In animal cells, the plasma membrane is the only bar... Cell disruption focuses on obtaining a desired bioproduct within a cell, and it is the cell wall that must be disrupted to allow access to the contents of the cell. In animal cells, the plasma membrane is the only barrier separating cell contents from the environment. Sound waves from sonication, a mechanical technique for cell disintegration, have been used to disrupt as well as to aggregate cells as a step towards purification of a desired bioproduct. In the present study, an improved sonication process for the high yield of Newcastle disease virus (NDV) propagated in tissue culture was described. DF-I cell was cultured in 25cm^2 T flask. When cells were about 80% confluent, a lentogenic strain of NDV (F strain) was used to infect the cell monolayer. With evident cytopathic effect, cells were subjected to cycles of freeze-thaw before sonicating with varying combinations of amplitude, temperature and time. Cells were sonicated using a water bath Sonicator, Jac Ultrasonic 1505 JEIO TECH 4 KHz. From ANOVA analysis, a significant interaction between sonication time and amplitude was observed. This also corresponds to the highest F value observed. 展开更多
关键词 Sonication TITER NDV DFI freeze-thaw.
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Noise properties in breaking and loose contacts and their effect on quality degradation of digital signal
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作者 TAKAGI Tasuku 《Journal of Zhejiang University-Science A(Applied Physics & Engineering)》 SCIE EI CAS CSCD 2007年第3期357-360,共4页
Electric contact discharge is subject closely related to digital information transmission, and integrity of digital signals for realizing high reliablility transmission. This kind of problem is a part of EMC (electrom... Electric contact discharge is subject closely related to digital information transmission, and integrity of digital signals for realizing high reliablility transmission. This kind of problem is a part of EMC (electromagnetic compatibility). From such a viewpoint, contact noise problems will be mentioned which disturb and degrade digital signals. The induction noise and radiation noise from discharge, electrostatic discharge (ESD), and connector related fundamental subject will be mentioned. 展开更多
关键词 EMC (electromagnetic compatibility) Electric contacts DISCHARGE Induction noise Radiation noise ESD (electrostatic discharge) CONNECTOR
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Diagnostic value of gadobenate dimeglumine-enhanced hepatocyte-phase magnetic resonance imaging in evaluating hepatic fibrosis and hepatitis 被引量:10
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作者 Xiu-Mei Li Zhu Chen +2 位作者 En-Hua Xiao Quan-Liang Shang Cong Ma 《World Journal of Gastroenterology》 SCIE CAS 2017年第17期3133-3141,共9页
AIM To evaluate the diagnostic value of gadobenate dimeglumine(Gd-BOPTA)-enhanced hepatocyte-phase magnetic resonance imaging(MRI) in evaluating hepatic fibrosis and hepatitis.METHODS Hepatocyte-phase images of Gd-BOP... AIM To evaluate the diagnostic value of gadobenate dimeglumine(Gd-BOPTA)-enhanced hepatocyte-phase magnetic resonance imaging(MRI) in evaluating hepatic fibrosis and hepatitis.METHODS Hepatocyte-phase images of Gd-BOPTA-enhanced MRI were retrospectively evaluated in 76 patients with chronic liver disease. These patients were classified into five groups according to either the histopathological fibrosis stage(S0-S4) or the histopathological hepatitis grade(G0-G4). The relative enhancement ratio(RE) of the liver parenchyma in the T1-vibe sequence was calculated by measuring the signal intensity before(SI pre) and 90 min after(SI post) intravenous injection of Gd-BOPTA using the following formula: RE =(SI post-SI pre)/SI pre. One-way analysis of variance was used to compare the difference between the relative RE in the hepatocyte phase(REh) and the stage of hepatic fibrosis and the grade of hepatitis. Pearson's productmoment correlation analysis was used to evaluate the relationship between the REh and the levels of serologic liver functional parameters.RESULTS According to histopathological hepatic fibrosis stage, the 76 patients were classified into five groups: 16 in S0, 15 in S1, 21 in S2, 9 in S3, and 15 in S4 group. According to histopathological hepatitis grade, the 76 patients were also classified into five groups: 0 in G0, 44 in G1, 22 in G2, 8 in G3, and 2 in G3 group. With regard to the stage of hepatic fibrosis, REh showed significant differences between the S2 and S3 groups and between the S2 and S4 groups(P < 0.05), but no significant difference was observed between the other groups. With regard to the grade of hepatitis, REh showed significant differences between the G1 and G2 groups and between the G1 and G4 groups(P < 0.05), but no significant difference was observed between the other groups. Increased REh showed correlations with decreased serum levels of TB, ALT and AST(P < 0.05). CONCLUSION To some extent, measuring the REh using Gd-BOPTAenhanced MRI might be a noninvasive technique for assessing the stage of hepatic fibrosis. This method is able to differentiate no/mild hepatitis from advanced hepatitis. TB, ALT and AST levels can predict the degree of liver enhancement in the hepatocyte phase of Gd-BOPTA-enhanced MRI. 展开更多
关键词 GD-BOPTA Magnetic resonance imaging Hepatocyte phase Relative enhancement Hepatic fibrosis
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Advanced imaging and visualization in gastrointestinal disorders 被引量:2
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作者 Odd Helge Gilja Jan G Hatlebakk +5 位作者 Svein φdegaard Arnold Berstad Ivan Viola Christopher Giertsen Trygve Hausken Hans Gregersen 《World Journal of Gastroenterology》 SCIE CAS CSCD 2007年第9期1408-1421,共14页
Advanced medical imaging and visualization has a strong impact on research and clinical decision making in gastroenterology. The aim of this paper is to show how imaging and visualization can disclose structural and f... Advanced medical imaging and visualization has a strong impact on research and clinical decision making in gastroenterology. The aim of this paper is to show how imaging and visualization can disclose structural and functional abnormalities of the gastrointestinal (GI) tract. Imaging methods such as ultrasonography, magnetic resonance imaging (MRI), endoscopy, endosonography, and elastography will be outlined and visualization with Virtual Reality and haptic methods. Ultrasonography is a versatile method that can be used to evaluate antral contractility, gastric emptying, transpyloric flow, gastric configuration, intragastric distribution of meals, gastric accommodation and strain measurement of the gastric wall. Advanced methods for endoscopic ultrasound, three-dimensional (3D) ultrasound, and tissue Doppler (Strain Rate Imaging) provide detailed information of the GI tract. Food hypersensitivity reactions including gastrointestinal reactions due to food allergy can be visualized by ultrasonography and MRI. Development of multi-parametric and multi-modal imaging may increase diagnostic benefits and facilitate fusion of diagnostic and therapeutic imaging in the future. 展开更多
关键词 ULTRASONOGRAPHY Medical imaging Functional imaging ELASTICITY
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Magnetic resonance elastography is accurate in detecting advanced fibrosis in autoimmune hepatitis 被引量:15
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作者 Jin Wang Neera Malik +4 位作者 Meng Yin Thomas C Smyrk Albert J Czaja Richard L Ehman Sudhakar K Venkatesh 《World Journal of Gastroenterology》 SCIE CAS 2017年第5期859-868,共10页
AIM To assess the value of magnetic resonance elastography (MRE) in detecting advanced fibrosis/cirrhosis in autoimmune hepatitis (AIH). METHODS In this retrospective study, 36 patients (19 treated and 17 untreated) w... AIM To assess the value of magnetic resonance elastography (MRE) in detecting advanced fibrosis/cirrhosis in autoimmune hepatitis (AIH). METHODS In this retrospective study, 36 patients (19 treated and 17 untreated) with histologically confirmed AIH and liver biopsy performed within 3 mo of MRE were identified at a tertiary care referral center. Liver stiffness (LS) with MRE was calculated by a radiologist, and inflammation grade and fibrosis stage in liver biopsy was assessed by a pathologist in a blinded fashion. Two radiologists evaluated morphological features of cirrhosis on conventional magnetic resonance imaging (MRI). Accuracy of MRE was compared to laboratory markers and MRI for detection of advanced fibrosis/cirrhosis. RESULTS Liver fibrosis stages of 0, 1, 2, 3 and 4 were present in 4, 6, 7, 6 and 13 patients respectively. There were no significant differences in distribution of fibrosis stage and inflammation grade between treated and untreated patient groups. LS with MRE demonstrated stronger correlation with liver fibrosis stage in comparison to laboratory markers for chronic liver disease (r = 0.88 vs -0.48-0.70). A trend of decreased mean LS in treated patients compared to untreated patients was observed (3.7 kPa vs 3.84 kPa) but was not statistically significant. MRE had an accuracy/sensitivity/specificity/positive predictive value/negative predictive value of 0.97/90%/100%/100%/90% and 0.98/92.3%/96%/92.3%/96% for detection of advanced fibrosis and cirrhosis, respectively. The performance of MRE was significantly better than laboratory tests for detection of advanced fibrosis (0.97 vs 0.53-0.80, p < 0.01), and cirrhosis (0.98 vs 0.58-0.80, p < 0.01) and better than conventional MRI for diagnosis of cirrhosis (0.98 vs 0.78, p = 0.002). CONCLUSION MRE is a promising modality for detection of advanced fibrosis and cirrhosis in patients with AIH with superior diagnostic accuracy compared to laboratory assessment and MRI. 展开更多
关键词 autoimmune hepatitis advanced fibrosis magnetic resonance elastography liver stiffness CIRRHOSIS
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Determination of Hg in soil by ultrasonic slurry sampling hydride generation atomic fluorescence spectrometry
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作者 LIANG Shu-xuan LV Tian-feng ZHOU Wei-jing SUN Han-wen 《Journal of Environmental Science and Engineering》 2008年第5期9-13,共5页
Ultrasonic aided slurry sampling hydride generation atomic fluorescence spectrometry (USS-HG-AFS) was developed for the determination of Hg in soil samples from a sewage-irrigated farm. 500 mg grounded soil was susp... Ultrasonic aided slurry sampling hydride generation atomic fluorescence spectrometry (USS-HG-AFS) was developed for the determination of Hg in soil samples from a sewage-irrigated farm. 500 mg grounded soil was suspended in agar solution by an ultrasound water bath before the HG-AFS determination. The results for the reference material of soil (serial number GBW-07411) agreed satisfactorily with the certified values. Results obtained by the developed procedure compared well with those after traditional acid digestion of samples. The detection limit are 6.7ngL-1 for Hg respectively, with average relative standard deviation values of 6.4% for analysis of a series of soil samples of different origin. The recoveries of the anatytes varied in the range from 95 to 107%. This observation has stimulated interest in fast, accurate and sensitive analytical methods for determination of metals in soil. 展开更多
关键词 hydride generation ultrasonic slurry sampling atomic fluorescence spectrometry SOIL trace element
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