Active Structural Acoustic Control of Interior Noise on a Raytheon 1900D

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国外振动噪声有源控制技术发展现状

国外振动噪声有源控制技术发展现状刘小玲;王旭;郭莹;刘亚凤【摘要】With the development of the economy,noise pollution is more and more realized to be a major concern in modern industrial societies. Traditionally, the reduction of structure-borne sound is achieved by means of passive methods. These methods include using damping materials, vibration isolation,and vibration absorber. Passive techniques give good performance in the mid and high frequency range.Unfortunately ,the added mass or volume required to reduce low frequency noise is often impractical. With the advances in digital computers, active control methods have emerged as practical alternatives to passive methods for reducing unwanted noise in the low frequency range. Active noise control has become a research hotspot in the field of modern vibration and noise control. This paper presents the importance of the active noise control, then analyses the development of active noise control in America, the UK and Australia.%随着经济的发展,噪声污染已成为工业社会主要关心的问题.传统的噪声控制主要采用被动的方法,如使用阻尼材料、隔振、吸振.被动控制在中高频段能起到很好的效果,但在低频段效果很不理想.随着电子技术的发展,作为用来替代被动控制以减少低频段噪声的有源控制方法出现了,并且逐渐成为现代振动噪声控制领域的研究热点.本文主要介绍了有源控制技术的重要性,以及该技术在美国、英国和澳大利亚等国家的发展现状.【期刊名称】《舰船科学技术》【年(卷),期】2011(033)004【总页数】5页(P151-155)【关键词】噪声有源控制;智能弹簧;选择性阻尼【作者】刘小玲;王旭;郭莹;刘亚凤【作者单位】中国船舶信息中心,信息资源部,北京,100192;中国船舶信息中心,信息资源部,北京,100192;中国船舶信息中心,信息资源部,北京,100192;中国船舶信息中心,信息资源部,北京,100192【正文语种】中文【中图分类】U661.440 引言有源控制技术最早起源于20世纪30年代，并在20世纪80年代中期至90年代中期达到高潮。

一般建筑术语英文翻译之一

常见的建筑术语的英文翻译集之一以下是一些常见的建筑术语的英文翻译集合之一：1. 建筑设计- Architectural Design2. 建筑结构- Building Structure3. 建筑材料- Building Materials4. 建筑施工- Building Construction5. 建筑成本- Construction Cost6. 建筑风格- Architectural Style7. 建筑师- Architect8. 建筑规划- Building Planning9. 建筑模型- Architectural Model10. 建筑面积- Building Area11. 建筑高度- Building Height12. 建筑容积率- Plot Ratio13. 建筑法规- Building Codes and Regulations14. 建筑节能- Energy Efficiency in Buildings15. 建筑智能化- Intelligent Buildings16. 绿色建筑- Green Buildings17. 可持续建筑- Sustainable Buildings18. 建筑声学- Architectural Acoustics19. 建筑光学- Architectural Optics20. 室内设计- Interior Design21. 景观设计- Landscape Design22. 结构设计- Structural Design23. 给排水设计- Water Supply and Drainage Design24. 暖通空调设计- HVAC Design25. 电气设计- Electrical Design26. 消防设计- Fire Protection Design27. 智能化系统设计- Intelligent System Design28. 施工组织设计- Construction Organization Design29. 施工图设计- Construction Drawing Design30. 装饰装修设计- Decoration and Finishing Design31. 建筑声学设计- Architectural Acoustics Design32. 建筑光学设计- Architectural Optics Design33. 建筑热工设计- Architectural Thermal Design34. 建筑美学设计- Architectural Aesthetic Design35. 建筑环境设计- Architectural Environment Design36. 建筑风水学- Feng Shui37. 建筑日照分析- Solar Analysis for Buildings38. 建筑通风分析- Ventilation Analysis for Buildings39. 建筑声环境分析- Acoustic Environment Analysis for Buildings40. 建筑光环境分析- Daylighting Environment Analysis for Buildings41. 建筑热环境分析- Thermal Environment Analysis for Buildings42. 建筑面积计算- Building Area Calculation43. 建筑楼层高度- Storey Height44. 建筑消防设计- Fire Protection Design for Buildings45. 建筑结构安全评估- Structural Safety Evaluation for Buildings46. 建筑抗震设计- Seismic Design for Buildings47. 建筑防洪设计- Flood-resistant Design for Buildings48. 建筑工程招标- Building Engineering Tendering49. 建筑工程施工许可- Construction Permission for Building Projects50. 建筑工程造价咨询- Engineering Cost Consulting for Building Projects51. 建筑工程监理- Project Supervision for Building Projects52. 建筑工程验收- Acceptance of Building Projects53. 建筑工程质量检测- Quality Detection of Building Projects54. 建筑工程质量评估- Quality Evaluation of Building Projects55. 建筑工程质量保修- Quality Guarantee of Building Projects56. 建筑工程档案- Construction Project Archives57. 建筑工程安全- Construction Safety58. 建筑工程管理- Construction Project Management59. 建筑工程合同- Construction Contract60. 建筑工程保险- Construction Insurance61. 建筑工程材料- Construction Materials62. 建筑工程机械- Construction Machinery63. 建筑工程劳务- Construction Labor64. 建筑工程施工组织设计- Construction Organization Design for Building Projects65. 建筑工程施工图设计- Construction Drawing Design for Building Projects66. 建筑工程施工进度计划- Construction Progress Plan for Building Projects67. 建筑工程施工质量控制- Construction Quality Control for Building Projects68. 建筑工程施工安全管理- Construction Safety Management for Building Projects69. 建筑工程施工现场管理- Construction Site Management for Building Projects70. 建筑工程施工成本管理- Construction Cost Management for Building Projects71. 建筑工程施工环境保护- Environmental Protection in Building Construction72. 建筑工程施工节能管理- Energy-saving Management in Building Construction73. 建筑工程施工水土保持- Soil and Water Conservation in Building Construction74. 建筑工程施工质量控制要点- Key Points of Construction Quality Control for Building Projects75. 建筑工程施工安全控制要点- Key Points of Construction Safety Control for Building Projects76. 建筑工程施工质量验收规范- Acceptance Specification for Construction Quality ofBuilding Projects77. 建筑立面设计- Façade Design78. 建筑剖面设计- Section Design79. 建筑立面分析图- Façade Analysis Diagram80. 建筑剖面分析图- Section Analysis Diagram81. 建筑结构分析图- Structural Analysis Diagram82. 建筑平面图- Floor Plan83. 建筑立面图- Façade Drawing84. 建筑剖面图- Section Drawing85. 建筑轴测图- Axonometric Drawing86. 建筑渲染图- Architectural Rendering87. 建筑模型制作- Model Making88. 建筑绘画- Architectural Drawing89. 建筑表现图- Architectural Representation90. 建筑动画- Architectural Animation91. 建筑摄影- Architectural Photography92. 建筑信息模型- Building Information Modeling (BIM)93. 建筑环境评估- Building Environmental Assessment94. 建筑节能评估- Building Energy Efficiency Assessment95. 建筑可持续性评估- Building Sustainability Assessment96. 建筑健康评估- Building Health Assessment97. 建筑设备系统设计- Building Equipment System Design98. 建筑电气系统设计- Electrical System Design for Buildings99. 建筑给排水系统设计- Water Supply and Drainage System Design for Buildings 100. 建筑暖通空调系统设计- HVAC System Design for Buildings。

fundamentals of acoustics中文版 -回复

fundamentals of acoustics中文版-回复Fundamentals of Acoustics（声学基础）是一门研究声音行为、传播和控制的学科。

声学是以物理学为基础，探究声音与其产生和传播环境之间相互作用的科学。

在本文中，我将逐步回答有关声学基础的问题，探讨声音行为以及声学的应用。

1. 声音是如何产生的？声音产生于物体或介质的振动。

当物体振动时，其分子也跟着振动，将能量传递给周围的分子。

这种传递的能量以波动形式传播，被我们听到的就是这些波动。

声音的特点包括频率、振幅和声音的复杂性。

2. 频率和振幅对声音的影响是什么？声音的频率决定了我们感知到的音调高低。

频率越高，音调越高；频率越低，音调越低。

振幅则决定了我们感知到的音量大小。

振幅越大，音量越大；振幅越小，音量越小。

3. 什么是声音的复杂性？声音的复杂性是指由多个频率组合而成的声波。

这些频率可以是同频率的正弦波的叠加，也可以是不同频率的波的混合。

复杂音包括音乐、语言和环境声音等。

4. 声音是如何传播的？声音通过介质传播，例如空气、水或固体。

当声音波在介质中传播时，它引起分子的振动，从而传递声音能量。

声音通过在介质中传递的压力变化来传播，这种压力变化形成了声波。

5. 声音传播中遇到的现象有哪些？声音传播中遇到的现象包括折射、吸收、干涉和衍射。

折射是声波穿过不同介质时改变传播方向的现象。

吸收是介质吸收部分声能并减弱声音的现象。

干涉是两个或多个声波相遇时相互增强或相互抵消的现象。

衍射是声波绕过障碍物传播的现象。

6. 如何应用声学？声学在许多领域有重要应用。

在音乐领域，声学帮助我们理解乐器的工作原理和声音的特性，从而改善音乐演奏和音质。

在建筑领域，声学用于设计能够减少噪音传播、改善声学环境的建筑结构。

在医学领域，声学用于诊断和治疗，如超声波医学成像和声波治疗。

此外，声学还应用于环境噪音控制、通信技术和声学工程等领域。

总结起来，声学基础是研究声音行为、传播和控制的学科。

声学超结构在车内低频轰鸣声控制中的应用

2021年第4期【摘要】针对某款轿车在30km/h 匀速行驶过程中产生明显的低频轰鸣声问题，通过测试和分析，确定了车内35Hz 噪声峰值过高是引发该问题的直接原因，并判断出该频率峰值与尾门薄壁件振动密切相关。

基于局域共振原理，设计了具有轻量化、小型化特征的声学超结构，并完成了谐振单元构型的选择与带隙设计、整车布置规划及谐振单元排布与基体框架设计。

实车测试结果表明：贴附声学超结构后，前排和后排35Hz 车内噪声声压级分别降低了4.23dB(A)、5.77dB(A)。

主题词：声学超结构结构声控制局域共振车内低频轰鸣中图分类号：U461.1文献标识码：ADOI:10.19620/ki.1000-3703.20200952The Application of Acoustic Superstructure on Control of LowFrequency Roaring in VehicleTang Jiyou 1,Ding Weiping 1,Wu Yudong 1,Huang Haibo 1,Luo Deyang 2（1.Southwest Jiao Tong University,Chengdu 610031;2.SAIC GM Wuling Automobile Co.,Ltd.,Liuzhou 545000）【Abstract 】Obvious low-frequency roaring sound is produced by a car model during the constant speed of 30km/h.By testing and analysis,it is determined that the high peak of 35Hz noise inside the car is the direct cause of this problem,and it is judged that the peak frequency is closely related to the vibration of thin-wall parts of the tail door.Furthermore,based on the principle of local resonance,a lightweight and miniaturized acoustic superstructure is developed,which involves the selection of its resonant unit configuration,band-gap design,vehicle layout planning,resonant unitarrangement,matrix frame size design.The real vehicle test shows that after attaching the acoustic superstructure,the noise of 35Hz in the car is reduced by 4.23dB(A)and 5.77dB(A)respectively in the front and rear rows.Key words:Acoustic superstructure,Structural sound control,Local resonance,Low frequencyRoaring in vehicle唐吉有1丁渭平1吴昱东1黄海波1罗德洋2（1.西南交通大学，成都610031；2.上汽通用五菱汽车股份有限公司，柳州545000）*基金项目：国家自然科学基金项目（51775451）。

基于模态振型形状优化的结构声辐射控制

第４６卷第９期２０１０年５月机械工程学报ＪＯＵＲＮＡＬＯＦＭＥＣＨＡＮＩＣＡＬＥＮＧ胍ＥＲＩＮＧＶｏＩ．４６ＮＯ．９Ｍａｖ２０１０ＤｏＩ：ｌＯ．３９０１／硼ⅥＥ．２０１０．０９．０７３基于模态振型形状优化的结构声辐射控制水臧献国于德介姚凌云郭建文（湖南大学汽车车身先进设计制造国家重点实验室长沙４１００８２）摘要：针对复杂结构形状难以参数化的问题，建立基于有限元网格的参数化形状优化模型，提出一种基于模态振型的结构形状优化方法以控制结构声辐射功率。

该方法通过有限元法计算结构的振动特性，然后采用瑞利积分进行结构的声辐射分析，在此基础上，用一组模态振型绝对值线性组合定义修改区域的形状优化函数，以每阶模态振型贡献因子为设计变量，通过改变模态振型贡献凶子来优化结构的形状，达到降低结构声辐射功率的目的。

研究简谐激励力下的结构声辐射优化，以结构声辐射分析频率带内的辐射声功率均值为设计目标，结构有限元结构坐标的最大变动值及模态频率为设计约束，利用序列二次规划算法进行优化求解。

以几何平板和复杂曲面为数值算例，研究结果表明该方法可以有效控制结构声辐射。

关键词：模态振型形状优化结构声辐射中图分类号：ＴＢ５３５ＣｏｎｔｒｏｌｏｆＳｔｒｕｃｔｕｒａｌＡｃｏｕｓｔｉｃＲａｄｉａｔｉｏｎＢａｓｅｄｏｎＭｏｄｅＳｈａｐｅＯｐｔｉｍｉｚａｔｉｏｎＺＡＮＧＸｉａｎｇｕｏＹＵＤｅｊｉｅＹＡＯＬｉｎｇｙｕｎＧＵＯＪｉａｎｗｅｎ（ＳｔａｔｅＫｅｙＬａｂｏｒａｔｏｒｙｏｆＡｄｖａｎｃｅｄＤｅｓｉｇｎａｎｄＭａｎｕｆａｃｔｕｒｉｎｇｆｏｒＶｅｈｉｃｌｅＢｏｄｙ，ＨｕｎａｎＵｎｉｖｅｒｓｉｔｙ，Ｃｈａｎｇｓｈａ４１００８２）Ａｂｓｔｒａｃｔ：Ｉｎｖｉｅｗｏｆｔｈｅｄｉｆｆｉｃｕｌｔｐａｒａｍｅｔｅｒｉｚａｔｉｏｎｐｒｏｂｌｅｍｏｆｃｏｍｐｌｅｘｓｔｒｕｃｔｕｒａｌｓｈａｐｅ，ａｐａｒａｍｅｔｅｄｚｅｄｓｈａｐｅｏｐｔｉｍｉｚａｔｉｏｎｍｏｄｅｌｂａｓｅｄｏｎｆｉｎｉｔｅｅｌｅｍｅｎｔｍｅｓｈｅｓｉｓｂｕｉｌｔａｎｄｓｔｒｕｃｔｕｒａｌｓｈａｐｅｏｐｔｉｍｉｚａｔｉｏｎｍｅｔｈｏｄｂａｓｅｄｏｎｍｏｄｅｓｈａｐｅｉｓｐｒｏｐｏｓｅｄｆｏｒｃｏｎｔｒｏｌｌｉｎｇｔｈｅｓｔｒｕｃｔｕｒａｌａｃｏｕｓｔｉｃｒａｄｉａｔｉｏｎｐｏｗｅｒ．Ｉｎｔｈｉｓｍｅｔｈｏｄ，ｓｔｒｕｃｔｕｒａｌｖｉｂｒａｔｉｏｎｃｈａｒａｃｔｅｒｉｓｔｉｃａｎａｌｙｅｄｂＹｕｓｉｎｇｆｉｎｉｔｅｅｌｅｍｅｎｔｍｅｔｈｏｄａｎｄｔｈｅｎｓｔｒｕｃｔｕｒａｌａｃｏｕｓｔｉｃｒａｄｉａｔｉｏｎｉｓａｎａｌｙｚｅｄｂｙｕｓｉｎｇＲａｙｌｅｉｇｈｉｎｔｅｇｒａｌ．Ｏｎｔｈｅｂａｓｉｓ，ｔｈｅｓｈａｐｅｏｐｔｉｍｉｚａｔｉｏｎｆｕｎｃｔｉｏｎｏｆｍｏｄｉｆｉｃａｔｉｏｎｄｏｍａｉｎｉｓｄｅｆｉｎｅｄｂｙｕｓｉｎｇａｌｉｎｅａｒｃｏｍｂｉｎａｔｉｏｎｏｆａｇｒｏｕｐｏｆｍｏｄｅｓｈａｐｅａｂｓｏｌｕｔｅｖａｌｕｅｓ，ａｎｄｅａｃｈｍｏｄｅｓｈａｐｅｃｏｎｔｒｉｂｕｔｉｏｎｆａｃｔｏｒｉｓｔａｋｅｎａｓａｄｅｓｉｇｎｖａｒｉａｂｌｅ．Ｔｈｅｓｔｒｕｃｔｕｒａｌｓｈａｐｅｉｓｏｐｔｉｍｉｚｅｄｂｙｃｈａｎｇｉｎｇｔｈｅｍｏｄｅｓｈａｐｅｃｏｎｔｒｉｂｕｔｉｏｎｆａｃｔｏｒｓｔｏｄｅｃｒｅａｓｅｔｈｅｓｔｒｕｃｔｕｒａｌａｃｏｕｓｔｉｃｒａｄｉａｔｉｏｎｐｏｗｅｒ．Ｓｔｒｕｃｔｕｒａｌａｃｏｕｓｔｉｃｒａｄｉａｔｉｏｎｏｐｔｉｍｉｚａｔｉｏｎｉｓｓｔｕｄｉｅｄｕｎｄｅｒｈａｒｍｏｎｉｃｅｘｃｉｔａｔｉｏｎ，ｔｈｅａｖｅｒａｇｅｖａｌｕｅｏｆａｃｏｕｓｔｉｃｒａｄｉａｔｉｏｎｐｏｗｅｒｉｎｔｈｅａｎａｌｙｓｉｓｆｒｅｑｕｅｎｃｙｂａｎｄａｃｏｕｓｔｉｃｒａｄｉａｔｉｏｎｉｓｔａｋｅｎａｓｄｅｓｉｇｎｏｂｊｅｃｔｉｖｅ，ｔｈｅｍａｘｉｍｕｍｖａｒｉａｂｌｅｖａｌｕｅｏｆｓｔｒｕｃｔｕｒａｌｃｏｏｒｄｉｎａｔｅｓａｎｄｍｏｄｅｆｒｅｑｕｅｎｃｙｔａｋｅｎ豳ｄｅｓｉｇｎｃｏｎｓｔｒａｉｎｔｓ．ａｎｄｔｈｅｐｒｏｂｌｅｍｉｓｓｏｌｖｅｄｂｙｕｓｉｎｇｓｅｑｕｅｎｔｉａｌｑｕａｄｒａｔｉｃｐｒｏｇｒａｍｍｉｎｇ．ＮｕｍｅｒｉｃａｌｅｘａｍｐｌｅｓｏｆａｐｌａｔｅａｎｄｃｏｍｐｌｅｘｓｕｒｆａｃｅａｒｅｐｒｅｓｅｎｔｅｄｔｏｓｈｏｗｔｈａｔｓｔｒｕｃｔｕｒａｌａｃｏｕｓｔｉｃｒａｄｉａｔｉｏｎＣａｎｂｅｃｏｎｔｒｏｌｌｅｄｅｆｆｅｃｔｉｖｅｌｙ．Ｋｅｙｗｏｒｄｓ：ＭｏｄｅｓｈａｐｅＳｈａｐｅｏｐｔｉｍｉｚａｔｉｏｎＳｔｒｕｃｔｕｒａｌａｃｏｕｓｔｉｃｒａｄｉａｔｉｏｎ０前言噪声污染是严重的环境污染之一。

铸铁刹车盘_毂材料摩擦磨损特性研究

铸铁的耐磨性能决定于基体组织与石墨形态 , 在基体组织基本相同的条件下 , 主要取决于石墨形态. 石墨形态影响材料的强韧性能 ,随着石墨形态由片状改变为蠕虫状、球状 , 铸铁的硬度逐渐提高 (见表 2) . 同时 , 减少了石墨尖端对基体造成的应力集中现象 ,使石墨对金属基体的破坏作用得到缓和 ,减缓了摩擦表面及亚表层裂纹萌生、扩展的速度 ,摩擦表面抗塑变能力和抗剪切能力提高 , 耐磨性能随之提高.
(a) 速度与摩擦系数波动范围的关系
(b) 接触压力与摩擦系数波动范围的关系图 3 速度、接触压力对摩擦系数波动范围的影响
(b) 接触压力与摩擦系数达到最大值的时间的关系图 4 不同速度、接触压力下摩擦系数达到最大值的时间
摩擦系数达到最大值的时间随接触压力的变化规律性不明显 ,随速度增加而迅速降低. 灰铁在任何情况下 ,其摩擦系数达到最大值所需的时间最长 ,蠕铁和球铁在高速、高接触压力条件下相近 , 相比较而言 , 蠕铁摩擦系数达到最大值所需的时间最短. 这说明蠕铁的制动效能在制动初始发挥得更为充分.
作为一对摩擦副 , 不仅要求盘试样材料的耐磨性能好 ,而且要求对配副方造成的磨损小. 图 6 为试验中测得的不同石墨形态铸铁盘试样和与之配副的
第 5 期陈跃 ,等 :铸铁刹车盘/ 毂材料摩擦磨损特性研究
83
(a) 速度与磨损率的关系
(a) 盘试样平均磨损率
试验中 ,将镍铬Ο镍硅热电偶置于盘块试样刚脱离接触的盘试样表面 ,与旋转的盘试样保持接触 ,用自动平衡记录仪记录测得的热电势 ,然后换算成温度值.
2 试验结果与分析
2. 1 摩擦特性图 2 为 3 种不同石墨形态铸铁材料在不同速度
v 、不同接触压力 N 下平均摩擦系数μ 的变化规律. 由图可见 ,随着速度、接触压力的增加 ,材料的摩擦系数降低 , 3 种铸铁材料的摩擦系数从大到小依次为灰铁、蠕铁、球铁 , 但在高速、高接触压力条件下 ,蠕铁的摩擦系数与灰铁相当.

在燃烧室燃烧振荡的反馈控制

Short communicationFeedback control of combustion oscillations in combustion chambersWei Wei a,*,Jing Wang a ,Dong-hai Li b ,Min Zhu b ,Ya-li Xue ba School of Information Engineering,University of Science and Technology Beijing,ChinabState Key Lab of Power Systems,Department of Thermal Engineering,Tsinghua University,Beijing,Chinaa r t i c l e i n f o Article history:Received 14November 2009Received in revised form 17December 2009Accepted 18December 2009Available online 28December 2009Keywords:Active control Model freeThermoacoustic instabilities Active compensation Longitudinal oscillationsa b s t r a c tModel-based algorithms are generally employed in active control of combustion oscilla-tions.Since practical combustion processes consist of complex thermal and acoustic cou-plings,their accurate models and parameters may not be obtained in advance economically,a model free controller is necessary for the control of thermoacoustic insta-bilities.Active compensation based control algorithm is applied in the suppression of com-bustion instabilities.Tuning the controller parameters on line,the amplitudes of the acoustic waves can be modulated to desired values.Simulations performed on a control oriented,typical longitudinal oscillations combustor model illustrate the controllers’capa-bility to attenuate combustion oscillations.Ó2009Elsevier B.V.All rights reserved.1.IntroductionCombustion oscillations have been plaguing designers of the propulsion and power generation systems,and oscillations arise more frequent when the combustors are under the operating condition of lean premixed to reduce the nitrous oxide emissions.Oscillations in combustion chambers occur as a result of couplings between the unsteady heat release rate and acoustic pressure.Their self-excited feedback loop can be diagrammed in Fig.1.Unsteady heat release is an efﬁcient acoustic source,and combustor may be high resonant systems [1].In most cases,such oscillations are unwanted since they can cause structural damage.Due to the oscillations’severity,a signiﬁcant multitude of efforts have made to prevent or alleviate them.Traditionally,two approaches are adopted to interrupt the couplings.Passive approaches,such as changing the combustors geometry or installing bafﬂes and acoustic dampers,resort to reduce the sensibility of the combustion process to the acoustic excitation [2–4].The problem is that they may be ineffective when the operating conditions are changed,and the changes of design involved are costly and time consuming.That is,the passive approaches have bad robustness.Active feedback control provides another way of suppressing oscillations in combustors.At ﬁrst,controllers are designed as a way of trial-and-error [5–7],which are empirical and unsuitable for practical instable combustion processes.Such ap-proaches can not provide guarantees of the stability and may excite the amplitude of the thermoacoustic oscillations.A con-troller,which can offer suitable gains and phases in real time,is desirable.Control theories are applied in interrupting the couplings between acoustic waves and unsteady combustion.Consequently,systematic approaches to controllers design are utilized.Model-based control algorithms are designed to decouple the physical processes leading to thermoacoustic instabilities.Adaptive control [8–11],robust control [12–14],LQR control [15,16],State-feedback [17]and PID [18–20]con-trol etc are intensively studied,all of which demonstrate the valid of active feedback control approaches in suppressing com-bustion oscillations.A summary of active control designs for combustion oscillations can be found in Ref.[1].However,the1007-5704/$-see front matter Ó2009Elsevier B.V.All rights reserved.doi:10.1016/sns.2009.12.020*Corresponding author.Address:Mailbox 136,University of Science and Technology Beijing,Beijing 100083,China.E-mail address:weiweiustb@ (W.Wei).Commun Nonlinear Sci Numer Simulat 15(2010)3274–3283Contents lists available at ScienceDirectCommun Nonlinear Sci Numer Simulatjournal homepage:www.else v i e r.c o m /l o c a t e /c n s n sexact models of the combustion processes needed in model-based algorithms are not practical or economical.A control algo-rithm,which does not depend on the precise mathematical models of the physical processes,is of signiﬁcance.In this paper,a controller,based on active compensation,is designed for the control-oriented model of unsteady motions in a combustor [17].The control technology employed here is model free and its parameters can be tuned easily to suppress the instabilities.In what follows,a control-oriented theoretical model of an unsteady combustion chamber is stated in Sec-tion 2.Control algorithm,stability analysis of the closed-loop system and the analysis of ability to suppress oscillations are given in Section 3.In Section 4,simulations are performed on the model stated in Section 2to demonstrate the controller.Section 5concludes the paper.2.Controlled dynamic models of combustion chambersYang et al.[17]developed control-oriented models for combustion processes,a set of linear ordinary differential equa-tions governing the dynamics of the combustor is given for the time-dependent amplitude of each mode [17]€g n þx 2n g n þXK i ¼1ðD ni _g i þE ni g i ÞþF NL n ðg 1;g 2;...;_g 1;_g 2;...Þ¼w n ðt ÞþU n ðt Þ;n ¼1;2;...;K ð1Þwhere w n ðt Þis the noise,D ni and E ni are linear coefﬁcients associated with growth rate and frequency shift,respectively.F NL nrepresents all nonlinear processes.K ,the number of the modes,should be inﬁnite to describe the combustion dynamics com-pletely.As a matter of fact,however,the unsteady motions can be represented by a truncated mode,i.e.K may be large but ﬁnite.The distributed control of the secondary fuel may be provided by M point actuators,each actuator supplies an exci-tation u i ðt Þat a position r i as shown in Fig.2.The control input to the n th mode can be written asU n ðt Þ¼a2 p E 2n X Mi ¼1u i ðt Þw n ðr i Þð2Þwhere E 2n ¼R R R w 2n dV is the Euclidean norm of the mode function,w n ¼cos n p L z is normal mode function,and a is the speed of sound in mixture.The unsteady pressure ﬁeld is measured by P point sensors,the sensor output measured at the position r j ,with the mea-surement noise modeled by a random function v j ðt Þ,in the chamber can be written as followsy j ¼c j pX K n ¼1g n ðt Þw n ðr j Þþv j ðt Þ;j ¼1;2;...;Pð3ÞThe controlled dynamics of combustion chambers are described in Eqs.(1)–(3).We consider the deterministic and linearsystems,i.e.w n ðt Þ¼v j ðt Þ¼0and F NL n ¼0.Nonlinear problems are considered in Ref.[19].According to Ref.[17],the ﬁrst N modes (N <K )are controlled,the state variables can be classiﬁed into controlled and uncontrolled (residual)parts as follows.x ¼½x N ;x R TFig.2.Scheme of active control system with distributed actuators.Fig.1.Thermoacoustic instabilities loop.W.Wei et al./Commun Nonlinear Sci Numer Simulat 15(2010)3274–32833275where,x N ¼½g 1;_g1;g 2;_g 2;...;g N ;_g N T ;x R ¼½g N þ1;_g N þ1;g N þ2;_g N þ2;...;g K ;_g K T .Thus,Eqs.(1)–(3)can be written as following state-space form_x N _x R ¼A N A NRA RN A Rx N x R þB N B R uy ¼C N x N þC R x R8<:ð4Þwhere,A N ;A NR and A R ;A RN are system matrices associated with controlled and uncontrolled modes.Input and output matri-ces are expressed by B N ;B R and C N ;C R ,respectively.u ¼½u 1;u 2;...;u M T 2R M ;y ¼½y 1;y 2;...;y P T 2R P .Similar to Ref.[17],two controlled and two residual modes of longitudinal oscillations are considered.We use one actu-ator and one sensor.Thus,the state variables,system matrices,input matrices,and the output matrices are shown below,respectively.x N ¼½g 1;_g1;g 2;_g 2 T ;x R ¼½g 3;_g 3;g 4;_g 4 T ;u 2R ;y 2R ;A N ¼0100Àðx 21þE 11ÞÀD11ÀE 12ÀD 12001ÀE 21ÀD 21Àðx 22þE 22ÞÀD 22B B B@1C CC A ;A R ¼0100Àðx 23þE 33ÞÀD33ÀE 34ÀD 34001ÀE 43ÀD 43Àðx 24þE 44ÞÀD 44B B B@1C CC AA NR¼0000ÀE 13ÀD 13ÀE 14ÀD 140000ÀE 23ÀD 23ÀE 24ÀD 240B B B @1C CC A ;A RN¼0000ÀE 31ÀD 31ÀE 32ÀD 320000ÀE 41ÀD 41ÀE 42ÀD 42B B B @1C CC A ð5ÞB N ¼0a 2w 1ðr Þ pE 210 a2w 2ðr Þp E 2B B B B B @1CC C C CA ;B R ¼0a 2w 3ðr Þ pE 230 a2w 4ðr Þp E 4B B B B B @1CC C C CA ;C N ¼ðc pw 10c pw 20Þ;C R ¼ðc p w 30c pw 40Þ3.Controller designIn this section,an active compensation based controller is designed to suppress the oscillations in combustion chambers,i.e.to make the amplitudes of the pressure oscillation g n approach zero.3.1.Control law and closed-loop block diagramAn active compensation based controller,proposed by Tornambe and Valigi [21],is employed here.We may call it TC con-troller in this paper.The control law,when relative degree is 1,has the formu ¼Àh 0ðy Ày r ÞÀ^d^d ¼n þk 0ðy Ày r Þ_n ¼Àk 0n Àk 20ðy Ày r ÞÀk 0u8>><>>:ð6Þwhere ^d is the extended state observer,which estimates the uncertainties.y is the output of the system.y ris the desired tra-jectory.n is the intermediate variable.h 0;k 0are tunable variables,and h 0determines,the response speed of the system.The control block diagram is shown in Fig.3.In the diagram,u c is the control output of the controller,u p is the control input of the combustion process.3276W.Wei et al./Commun Nonlinear Sci Numer Simulat 15(2010)3274–32833.2.Stability analysisControl law Eq.(6)can be rewritten as e¼yrÀyu¼ðh0þk0ÞeÀn_n¼Àh0k0e8><>:ð7ÞTo simplify the notation,we have c1¼Àðh0þk0Þ;c2¼h0k0.Under the function of TC controller,the closed-loop state-space description of the system Eq.(5)is given belowx¼½g1;_g1;g2;_g2;g3;_g3;g4;_g4;n T;_x¼Aclxwhere A cl¼010000000Àðx21þE11Þþ a2w1ðrÞp E21c p w1ðrÞc1ÀD11ÀE12þ a2w1ðrÞp E21c p w2ðrÞc1ÀD12ÀE13ÀD13ÀE14ÀD14À a2w1ðrÞp E21000100000ÀE21þ a2w2ðrÞp E22c p w1ðrÞc1ÀD21Àðx22þE22Þþ a2w2ðrÞp E22c p w2ðrÞc1ÀD22ÀE23ÀD23ÀE24ÀD24À a2w2ðrÞp E22000001000ÀE31þ a2w3ðrÞp E23c p w1ðrÞc1ÀD31ÀE32þ a2w3ðrÞp E23c p w2ðrÞc1ÀD32Àðx23þE33ÞÀD33ÀE34ÀD34À a2w3ðrÞp E23000000010ÀE41þ a2w4ðrÞp E24c p w1ðrÞc1ÀD41ÀE42þ a2w4ðrÞp E24c p w2ðrÞc1ÀD42ÀE43ÀD43Àðx24þE44ÞÀD44À a2w4ðrÞp E24c p w1ðrÞc20c p w2ðrÞ20000000 B B B B B B B B B B B B B B B B B B @1 C C C C C C C C C C C C C C C C C C Að8ÞCorollary1.If A cl is Hurwitz,the closed-loop system is asymptotically stable.We note that the characteristic polynomial of closed-loop system Eq.(8)is j k IÀA cl j¼k9þa8k8þÁÁÁþa1kþa0.If all the roots of j k IÀA cl j¼0have negative real parts,the closed-loop system is asymptotically stable.Note that the matrixQ¼a8a6a4a2a000001a7a5a3a100000a8a6a4a2a000001a7a5a3a100000a8a6a4a2a000001a7a5a3a100000a8a6a4a2a000001a7a5a3a100000a8a6a4a2a0B BB BB BB BB BB BB BB B@1C CC CC CC CC CC CC CC CAAccording to the Hurwitz criterion[22],fðkÞis Hurwitz if and only if the matrix Q’s leading principal minors are positive:detq11q12...q1kq21...q2k.........qk1qk2...qkkB BB BB@1C CC CC A>0;k¼1;2;...;9:ð9Þthat is,D1¼a8>0;D2¼a8a61a7>0;D3¼a8a6a41a7a50a8a6>0;D4¼a8a6a4a21a7a5a30a8a6a401a7a5>0;D5¼a8a6a4a2a01a7a5a3a10a8a6a4a201a7a5a300a8a6a4>0;W.Wei et al./Commun Nonlinear Sci Numer Simulat15(2010)3274–32833277D 6¼a 8a 6a 4a 2a 001a 7a 5a 3a 100a 8a 6a 4a 2a 001a 7a 5a 3a 100a 8a 6a 4a 2001a 7a 5a 3>0;D 7¼a 8a 6a 4a 2a 0001a 7a 5a 3a 1000a 8a 6a 4a 2a 0001a 7a 5a 3a 1000a 8a 6a 4a 2a 0001a 7a 5a 3a 100a 8a 6a 4a 2>0;D 8¼a 8a 6a 4a 2a 00001a 7a 5a 3a 10000a 8a 6a 4a 2a 00001a 7a 5a 3a 10000a 8a 6a 4a 2a 00001a 7a 5a 3a 10000a 8a 6a 4a 2a 001a 7a 5a 3a 1>0;D 9¼a 8a 6a 4a 2a 000001a 7a 5a 3a 100000a 8a 6a 4a 2a 000001a 7a 5a 3a 100000a 8a 6a 4a 2a 000001a 7a 5a 3a 100000a 8a 6a 4a 2a 000001a 7a 5a 3a 100a 8a 6a 4a 2a 0>0:are satisﬁed.Thus,the A cl is Hurwitz,or the closed-loop system is asymptotically stable.3.3.Analysis of the ability to suppress oscillationsIn order to illustrate the capable of suppressing oscillations,we make an assumption that y ¼sin ðX t Þ.Substituting y intoEq.(7),we have e ¼Àsin ðX t Þand u ¼c 1sin ðX t Þþc 2cosðX t ÞXþC ,where C is the integral constant.It is obvious that the phase-shift resulting from the control input depends on the term c 1sin ðX t Þþc 2cosðX t Þ.As a matter of fact,c 1sin ðX t Þþc 2cos ðX t ÞX¼1X ½c 1X sin ðX t Þþc 2cos ðX t Þ ¼1X ﬃﬃﬃﬃﬃﬃﬃﬃﬃﬃﬃﬃﬃﬃﬃﬃﬃﬃﬃﬃﬃc 21X 2þc 22q sin X t þarctan c21Xh i ¼1ﬃﬃﬃﬃﬃﬃﬃﬃﬃﬃﬃﬃﬃﬃﬃﬃﬃﬃﬃﬃﬃﬃﬃﬃﬃﬃﬃﬃﬃﬃﬃﬃﬃﬃﬃﬃﬃﬃﬃﬃﬃﬃﬃðh 0þk 0Þ2X 2þh 20k 20q sin X t Àarctan h 0k 000 h iHence,the phase-shift made by control input is arctan h 0k 0h 0X þk 0X,in other words the time delay on account of the control in-put is 1X arctan h 0k 00X 0X.This explains why the TC controller is capable of suppressing the combustion instabilities in combustors.4.Simulations for the modelTo demonstrate the TC controller,we performed simulations for the four modes of longitudinal pressure oscillations.The normalized natural radian frequency of the fundamental mode and the ampliﬁcation factor (c )of the pressure signal are both taken to be unity.The linear parameters D ni and E ni in Eq.(1)are given in Table 1.According to Ref.[17],the optimal locations of actuators and sensors are selected to be at z o ¼L =7:5.L is taken as 76.2cm as in Ref.[18].In this paper,we deﬁne e as the ratio of u cmax to y max .Simulations are performed on system Eq.(5),the results are shown below,respectively (see Figs.4–9).Table 1System parameters.i =1i =2i =3i =4D ni n =1À0.010.007À0.0010.007n =20.010.10.007À0.001n =3À0.010.010.750.008n =40.02À0.0050.01 1.50E ni n =1À0.005À0.0050.00250.016n =2À0.0025À0.0150.010.01n =3À0.0050.0À0.020.02n =40.010.020.02À0.00253278W.Wei et al./Commun Nonlinear Sci Numer Simulat 15(2010)3274–3283W.Wei et al./Commun Nonlinear Sci Numer Simulat15(2010)3274–328332794.1.Simulation results for TCThe parameters and performance indexes of TC controllers are given in Table2.To check whether the closed-loop system is asymptotically stable under the function of TC controller,we verify the Eq.(9)for each system.3280W.Wei et al./Commun Nonlinear Sci Numer Simulat15(2010)3274–3283(1)Under the function of TC1,the characteristic polynomial of closed-loop system Eq.(8)is j k IÀA cl j¼k9þ2:34k8þ8165:7k7þ18846:2k6þ234295:1k5þ264215:2k4þ1714489:6k3þ576571:9k2þ2933414:7kþ12191:5, and D1¼2:34,D2¼261:5,D3¼4264354:8,D4¼5:1079Â1011,D5¼1:7429Â1016,D6¼1:8386Â1022,D7¼4:2955Â1026,D8¼1:0029Â1033,D9¼1:2227Â1037.Eq.(9)is satisﬁed,the closed-loop system is asymptotically stable.W.Wei et al./Commun Nonlinear Sci Numer Simulat15(2010)3274–32833281Table2Parameters and performance indexes of TC.TC k0h0u cmax y max e IAE10.020.00530.00170.06830.0247 3.278620.040.00640.00310.06830.0454 2.553230.050.00450.00360.06830.0533 2.39573282W.Wei et al./Commun Nonlinear Sci Numer Simulat15(2010)3274–3283Table3Parameters and performance indexes of phase-shift control.Phase-shift s c k p u cmax y max e IAE10.3À0.02530.00170.06830.0247 3.398920.2À0.04640.00310.06830.0454 2.606630.3À0.05450.00360.06830.0533 2.4872Table4Comparison of TC and phase-shift controller.e IAETC controller Phase-shift controller0.0247 3.2786 3.39890.0454 2.5532 2.60660.0533 2.3957 2.4872(2)Under the function of TC2,the characteristic polynomial of closed-loop system Eq.(8)is j k IÀA cl j¼k9þ2:34k8þ14949:8k7þ34551k6þ429514:8k5þ484984:4k4þ3144421:4k3þ1061213:2k2þ5381370:2kþ29447, and D1¼2:34,D2¼431:5,D3¼13692874:4,D4¼3:0075Â1012D5¼1:8922Â1017,D6¼3:6443Â1023, D7¼1:6566Â1028,D8¼6:6567Â1034,D9¼1:9602Â1039.Eq.(9)is satisﬁed,the closed-loop system is asymptoti-cally stable.(3)Under the function of TC3,the characteristic polynomial of closed-loop system Eq.(8)is j k IÀA cl j¼k9þ2:34k8þ17554:1k7þ40551:4k6þ504393:7k5þ568912:4k4þ3692469:9k3þ1241233:6k2þ6319299:4kþ25882:3, and D1¼2:34,D2¼525:2,D3¼19866748:8,D4¼5:127Â1012,D5¼3:7695Â1017,D6¼8:5727Â1023, D7¼4:28Â1028,D8¼2:1563Â1035,D9¼5:5811Â1039.According to Eq.(9),the closed-loop system is also asymp-totically stable.The time traces of closed-loop systems are shown in Figs.4–6,respectively.A popular control algorithm utilized for suppressing the combustion oscillations in experimental devices is phase-shift control,and it is independent of exact models of the physical processes.For the reasons above,we choose the standard con-trol algorithm,i.e.phase-shift control,as the benchmark,and make some comparison with TC controller.Simulations are performed on the same system with the same parameters.The results are given in Figs.7–9,respectively.4.2.Simulation results for phase-shiftThe parameters and performance indexes of phase-shift controllers are shown in Table3.The time traces of closed-loop systems are given in Figs.7–9,respectively.From Figs.4-9and IAE values given in Tables2and3,we can see that the TC controller,under the same control cost,is superior to the phase-shift controller.To show the advantages of TC controller over the phase-shift controller more distinct, we have Table4.From Table4,we may see clearly that the IAE values of TC controller,at the same price of control input,is minimal.In contrast to the phase-shift controller,the TC controller parameters has obvious physical interpretation,therefore the param-eter adjustments are more practicable.5.ConclusionIn this paper,a combustor model,which takes account of the inﬂuences of acoustic andﬂame dynamics,is considered and active compensation based controllers are adopted in the suppression of combustion oscillations.Controller employed,by comparison,does not need the prior knowledge of the process models.Tuning the parameters on line,the control action can suppress the amplitudes of oscillations to prespeciﬁed values,which may provide a realistic solution.However,the work in this paper is a necessary preparation for practical applications.With the purpose of verifying the control algorithm employed in this paper,the higher order and nonlinear models describing the combustion dynamics more exactly will be taken into account.Furthermore,the experimental veriﬁcation is of importance in the forthcoming research as well.AcknowledgementThis work is supported by National Basic Research Program of China Grant No.2007CB210106.W.Wei et al./Commun Nonlinear Sci Numer Simulat15(2010)3274–32833283 References[1]Dowling AP,Morgans AS.Feedback control of combustion oscillations.Annu Rev Fluid Mech2005;37:151–82.[2]Culick F.,Combustion instabilities in liquid-fueled propulsion systems:an overview.In:AGA-RD conference on combustion instabilities in liquid-fueled propulsion systems;1988.[3]Steele RC,Cowell LH,Cannon SM,Smith CE.Passive control of combustion instability in lean premixed combustors.J Eng Gas Turbines Power2000;122(3):412–9.[4]Richards GA,Straub DL,Robey EH.Passive control of combustion dynamics in stationary gas turbines.J Prop Power2003;19(5):795–810.[5]Ffowcs Williams JE.Antisound.Proc Roy Soc London1984;A395:63–88.[6]Langhorne PJ,Dowling AP,Hooper N.A practical active control system for combustion oscillations.J Prop Power1990;6:324–33.[7]Seume J,Vortmeyer N,Krause W,Hermann J,Hantschk C,Zangl P.Application of active combustion instability control to a heavy duty gas turbine.J EngGas Turbines Power1998;120:721–6.[8]Billoud G,Galland 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声学双曲构型超材料的负折射特性研究

第53卷第2期2024年2月人㊀工㊀晶㊀体㊀学㊀报JOURNAL OF SYNTHETIC CRYSTALS Vol.53㊀No.2February,2024声学双曲构型超材料的负折射特性研究刘㊀松1,赵仁洁1,杜一帆1,吴㊀芳2,宋和滨3,高㊀鹏3(1.大连理工大学工业装备结构分析优化与CAE 软件全国重点实验室,大连㊀116024;2.大连船舶重工集团有限公司,大连㊀116011;3.中国船级社(CCS)大连分社,大连㊀116013)摘要:声学双曲超材料是具有双曲色散特性的人工材料,具有极强的各向异性,其负折射特性是研究实现高分辨率聚焦型超透镜的理论依据㊂针对远场噪声源识别受制于0.5倍波长声波瑞利衍射识别分辨率问题,结合声学超材料对声波的优异调控效果,引进可以实现亚波长超分辨率成像的双曲超材料,利用其负折射特性设计了一种用于工作频率为2271.5Hz 的声学双曲结构㊂分析了该构型的双曲结构色散特性及负折射特性,结果表明声波在该双曲超材料中传播的群速度方向垂直于波矢,并沿着色散曲线的法线方向㊂本文的研究为实现对声波和弹性波的任意调控,以及噪声源的聚焦定位㊁识别放大等提供了一定的设计参考㊂关键词:声学超材料;声学透镜;弹性波带隙特性;负折射;双曲色散;声聚焦中图分类号:O735;TL375.2㊀㊀文献标志码:A ㊀㊀文章编号:1000-985X (2024)02-0246-06Negative Refraction Characteristics of Acoustic Hyperbolic Configuration MetamaterialsLIU Song 1,ZHAO Renjie 1,DU Yifan 1,WU Fang 2,SONG Hebin 3,GAO Peng 3(1.State Key Laboratory of Structural Analysis,Optimization and CAE Software for Industrial Equipment,Dalian University of Technology,Dalian 116024,China;2.Dalian Shipbuilding Industry Company,Dalian 116011,China;3.China Classification Society (CCS)Dalian Branch,Dalian 116013,China)Abstract :Acoustic hyperbolic metamaterials are artificial materials with hyperbolic dispersion characteristics and strong anisotropy.Their negative refractive properties are the theoretical basis for studying the implementation of high-resolution focused superlenses.In response to the problem that the recognition of far-field noise sources is limited by the resolution of 0.5times wavelength acoustic Rayleigh diffraction recognition,combined with the excellent control effect of acoustic metamaterials on sound waves,a hyperbolic metamaterial that can achieve sub wavelength super-resolution imaging is introduced,and its negative refractive characteristics are used to design an acoustic hyperbolic structure for working at a frequency of 2271.5Hz.The dispersion and negative refraction characteristics of the hyperbolic structure of this configuration were analyzed,and the results show that,the group velocity direction of sound waves propagating in this hyperbolic metamaterial is perpendicular to the wave vector and follows the normal direction of the dispersion curve.The research in this paper provides some design references for realizing arbitrary regulation of sound wave and elastic wave,as well as focusing,locating,identifying and amplifying noise sources.Key words :acoustic metamaterial;acoustic lens;elastic wave bandgap characteristic;negative refraction;hyperbolic dispersion;acoustic focusing㊀㊀收稿日期:2023-08-21㊀㊀基金项目:国家自然科学基金(51609037)㊀㊀作者简介:刘㊀松(1982 ),男,吉林省人,博士,高级工程师㊂E-mail:liusong@0㊀引㊀㊀言负折射率材料是某一特定频段下折射率为负数的新型超材料,当入射波与折射波位于法线的同侧时被称作负折射㊂正常聚焦透镜只聚焦传输波的能量,但是负折射材料可以在聚焦传输波的基础上继续聚焦倏㊀第2期刘㊀松等:声学双曲构型超材料的负折射特性研究247㊀逝波的能量,可以突破衍射极限,形成完美透镜㊂该类材料最早在电磁波领域被提出,前苏联物理学家Veselago[1]通过大量的理论推导设想了一种介电常数和磁导率均为负数的材料,具有负的折射率,当电磁波通过具有该特性的材料后出现负折射效应和声聚焦特性㊂Pendry[2]根据负折射的理论制备出具有等效负介电常数的周期性特性的超材料㊂Smith等[3]与Shelby等[4]设计了一种棱镜,首次从实验角度证实了负折射现象的真实存在,并由此实验证明当光线入射到负折射率介质表面时,折射光线与入射光线分布在分界面一侧㊂声学超材料具有与电磁材料通过周期性结构来调控电磁波传播的相似性[5]㊂声学超材料的特殊属性,尤其是负折射特性研究可为声场聚焦和声源定位提供支撑[6]㊂声学双曲超材料是具有双曲色散特性的人工材料,具有极强的各向异性,通过改变双曲材料结构尺寸㊁分布规律能够完成对声波强度和传播方向的控制[7]㊂对于声场聚焦问题,需要根据声源特性或设定的带宽对超材料进行详细的拓扑优化设计㊂王涵[8]从声学超材料的波衰减特性和双负特性这两个重要性质入手,提出三种新型蜂窝声学超材料均具有双负特性,但并未证实其负折射线现象㊂宋刚永[9]设计了基于变换声学理论的浸没式声学放大透镜,通过实验验证该透镜可在5650~6350Hz实现声场聚焦㊂杨帅等[10]在空气中将工字钢排列为正方形实现了负折射率,但只有在特定的频率范围,如5000Hz左右,声波在Z型线性波导中才能够较好地传播㊂整体来讲,目前双曲超材料的带隙频段较高,随着声源特性频率的降低,需设计可用于中低频段的超材料㊂本文基于拓扑优化方法,设计了一种可用于中低频段声场调控的双曲构型,从平面波入射三角棱镜声场分布研究入手,通过数值模拟方法分析了该构型的双曲结构色散特性及负折射特性㊂1㊀声学双曲构型设计在能够保持晶格对称性的前提下,构成晶体的最小的周期性结构单元称为晶体的单胞㊂本文设计双曲构型单胞示意图如图1所示,晶格常数a=26mm,交错分布的结构臂长d为22.5mm,壁厚t为1mm,尺寸构型由两个对称分形组成,两部分间隔c为2mm㊂图1㊀双曲构型单胞示意图Fig.1㊀Schematic diagram of the acoustic hyperbolic configuration metamaterial 本文设计亮点在于声子晶体内部有交错分布的结构臂,当声波通过此结构后能够延长声波的传递路径,进而延长了声波总的传播时间,最终实现对声波的相位调控㊂2㊀能带图分析结合双曲构型单胞特点,采用正方形晶格计算其能带特性,正方形晶格不可约布里渊区示意如图2所示㊂数值模拟双曲构型能带结构时,边界条件选为Floquet周期,根据Bloch定理可知,将波矢k沿着倒格矢空间内不可约布里渊区边界进行扫掠,即可得到能带结构,同时得到各能带对应的结构振动模态㊂扫掠方向为M-Γ-X-M㊂材料参数为:泊松比σ=0.41㊁弹性模量E=2450MPa㊁波速c1=716m/s,密度ρ1=1300kg/m3㊂空气参数为:密度ρ2=1.21kg/m3,速度c2=343m/s㊂计算得到的能带结构如图3所示㊂图中横坐标为波矢k的扫掠方向,即形成一个完整的扫掠回路;纵坐标为扫掠所对应的频率,频率范围为0~6000Hz㊂通过对所设计构型的能带结构模拟研究,从能带结构图中可以发现,第二能带的带顶较平,并且关于Γ248㊀研究论文人工晶体学报㊀㊀㊀㊀㊀㊀第53卷点附近对称性较好,共振频率为2271.5Hz㊂这表明声学超材料拥有更多的分支㊁更长的传播路径,且在此频率附近将出现负折射现象㊂图2㊀正方形晶格不可约布里渊区示意图[11]Fig.2㊀Schematic diagram of irreducible Brillouin region of a square lattice[11]图3㊀设计的双曲超材料的能带结构图Fig.3㊀Energy band structure diagram of designed hyperbolic metamaterials 3㊀色散特性在二维空间内,声学双曲超材料的等频线分布情况可以用声波色散方程描述:k 2x ρx +k 2y ρy =ω2B (1)式中:k x 为x 方向的波矢分量,k y 为y 方向的波矢分量,ρx 为x 方向的等效密度分量,ρy 为y 方向的等效密度分量,ω为声波波数,B 为等效模量㊂本文设计的双曲构型在2271.5Hz 时的等频线为双曲分布,双曲色散曲线如图4(a)所示,入射波由自由空间入射到双曲媒质,其入射波的传播方向为k i ㊁折射方向为k r 及双曲媒质中的群速度方向为v g ,其中群速度与频率关系式由v g =Δk ω可知其群速度的方向垂直于波矢,即沿着色散曲线的法线方向㊂尽管折射波的相速度为正,但入射波与折射波的能流都在法线同侧,因而此时出现负折射㊂图4(b)为通过COMSOL Multiphysics 软件提取的双曲构型的二维等频色散分布图㊂图4㊀双曲构型色散曲线示意图Fig.4㊀Diagram of hyperbolic configuration dispersion curve 4㊀折射率计算双曲构型超材料折射率计算示意图如图5所示,计算区域由五大部分组成:完美匹配层(perfectly matched layer,PML)-背景压力场-双曲构型-周期性边界-完美匹配层㊂背景压力场区域提供幅值为1Pa 的㊀第2期刘㊀松等:声学双曲构型超材料的负折射特性研究249㊀平面波,模拟声波入射环境;图中四个红点表示提取双曲构型前后声压值的位置点,在声波入射方向布置两个传声器1和2,分别在距离单胞左边界30和0mm 处,在构型右侧同样布置2个传声器3和4,提取四个位置点的声压值便于后续计算㊂在COMSOL Multiphysics 压力声学频域中进行计算㊂进行网格划分时,完美匹配层划分5层网格,其余部分按照四边形网格划分,单元尺寸选为1mm㊂在折射率图中横坐标为扫频频率,范围为2000~3000Hz,纵坐标为各个频率计算得到对应的折射率㊂计算的双曲构型单胞尺寸选为26mm ˑ26mm,背景压力场尺寸选为26mm ˑ150mm,周期性边界尺寸选为26mm ˑ150mm,完美匹配层尺寸选为26mm ˑ130mm,图5中可看到计算域的划分以及各区域的名称㊂为保证超材料出现中低频带隙特性,将构型在2000~3000Hz 的频率范围内在空气场中作扫频分析,计算声场的尺寸为510mm ˑ26mm,随后提取构型左边界的入射声压及左边界的出射声压随之得到该双曲材料的透射系数与反射系数,得到透射系数和反射系数后可以得到折射率的表达式n =-i lg x +2πm ka (2)式中:k =ωC 0为声波波数,ω为圆频率,C 0为声波声速,ω=2πf ,f 为频率;m 为反余弦函数分支,仅能取整数,由于实际声传播方向不存在周期性结构,故m =0;i 为虚数㊂x =1-R 2P +T 2P +r 2T P (3)r =ʃ(R 2P -T 2P -1)-4T 2P(4)式中:T P 为透射系数,R P 为反射系数,n 为折射率,a 为晶格常数,取值为26mm㊂计算得本双曲构型折射率如图6所示,可以清晰看到本构型在2271.5Hz 时的折射率为负数㊂图5㊀COMSOL 计算折射率示意图Fig.5㊀COMSOL calculation of refractive index diagram 图6㊀双曲构型折射率计算示意图Fig.6㊀Schematic diagram for calculating refractive index of hyperbolic configuration 5㊀负折射特性数值仿真验证通过有限元分析方法对双曲构型的负折射特性进行仿真验证㊂将双曲构型排列为边长尺寸为461mm 的三角棱镜(见图7),置于自由场中,四周采用完美匹配层营造良好的吸声效果,避免回波干扰;在棱镜左侧设置介质为空气的背景压力场平面波幅值为1Pa,三角棱镜右侧部分设为空气域,如图8所示㊂为对比双曲构型负折射特性仿真的效果,在保证计算域条件相同的情况下,分别探讨了有无三角棱镜的声场传播特性㊂首先给出平面波在空气域中的传播特性,可以看到平面波在声场中均匀传播,如图9所示㊂然后在声场中添加三角棱镜,在棱镜左侧施加平面波完成激励,平面波的入射方向沿棱镜左侧向右(如图250㊀研究论文人工晶体学报㊀㊀㊀㊀㊀㊀第53卷10)㊂观察平面波穿过声学双曲介质排布而成三角棱镜后的声场分布可以清晰看出,当声波在经过声学双曲超材料三角棱镜的声波调控后,入射波与经过声学双曲超材料调控后的折射波位于法线同侧,即出现了负折射现象㊂为了使负折射效果更加明显,该部分放大了显示倍数,且在完美匹配层的声学边界中对声压进行计算,证明了声压呈现衰减状态,声波传播无反射㊂图7㊀双曲构型棱镜示意图Fig.7㊀Schematic diagram of a hyperbolic configurationprism图8㊀COMSOL负折射验证示意图Fig.8㊀Schematic diagram of negative refractionverification图9㊀平面波无棱镜声场分布示意图Fig.9㊀Schematic diagram of plane wave sound field withoutprism图10㊀平面波入射三角棱镜声场分布示意图Fig.10㊀Schematic diagram of plane wave incidentsound field of triangular prism 从平面波有无三角棱镜耦合的声场分布图对比来看,负折射率的双曲介质对平面波的传播起到了调控作用,当声波穿过透镜后声波的传播方向得到了改变,入射声波经声学双曲超材料调控后的折射波与入射波位于法线的同侧㊂由斯涅耳定律可知,棱镜的折射率为负数,该材料存在负折射现象,经过有限元仿真验证了所设计声学双曲超材料的负折射属性㊂这说明本文所设计的声学双曲超材料单元可以对相应声波进行调控,该双曲构型后续可以用于声学透镜的聚焦㊂6㊀结㊀㊀论本文提出一种声学双曲超材料构型,分析了该构型的负折射特性,基于有限元分析软件对该构型的折射率进行了计算,折射率为负数,该构型满足负折射的条件㊂从能带结构图中可以发现第二能带的带顶较平,并且关于Γ点附近对称性较好,共振频率为2271.5Hz㊂这表明本文设计的声学双曲超材料拥有较多分支,对声波的传播路径可以有效延长,且在此频率附近出现了负折射现象,可用于声波调控及声场聚焦㊂本文的研究为实现对声波和弹性波的任意调控,以及远场噪声源的聚焦定位㊁识别放大等方面提供了一定的设计参考㊂参考文献[1]㊀TANASHYAN M M,LAGODA O V,VESELAGO O V,et al.A pathogeneteic approach to the treatment of vestibular disorders in angioneurology[J].Zhurnal Nevrologii i Psikhiatrii Im S S Korsakova,2019,119(5):32.[2]㊀PENDRY J B.Transfer matrices and conductivity in two-and three-dimensional systems.I.Formalism[J].Journal of Physics:CondensedMatter,1990,2(14):3273-3286.㊀第2期刘㊀松等:声学双曲构型超材料的负折射特性研究251㊀[3]㊀SMITH D R,PADILLA W J,VIER D C,et posite medium with simultaneously negative permeability and permittivity[J].PhysicalReview Letters,2000,84(18):4184-4187.[4]㊀SHELBY R A,SMITH D R,SCHULTZ S.Experimental verification of a negative index of refraction[J].Science,2001,292(5514):77-79.[5]㊀李丽萍.分形声学超材料声学特性研究[D].长沙:湖南大学,2018.LI L P.Study on acoustic characteristics of fractal acoustic metamaterials[D].Changsha:Hunan University,2018(in Chinese).[6]㊀LI J,FOK L,YIN X B,et al.Experimental demonstration of an acoustic magnifying hyperlens[J].Nature Materials,2009,8(12):931-934.[7]㊀SHEN C,XIE Y B,SUI N,et al.Broadband acoustic hyperbolic metamaterial[J].Physical Review Letters,2015,115(25):254301.[8]㊀王㊀涵.蜂窝型声学超材料带隙特性与双负特性的数值模拟研究[D].秦皇岛:燕山大学,2022.WANG H.Numerical simulation study on bandgap and double negative characteristics of honeycomb acoustic metamaterials[D].Qinhuangdao: Yanshan University,2022(in Chinese).[9]㊀宋刚永.声学超材料对声波的调控理论与实验研究[D].南京:东南大学,2019.SONG G Y.Theoretical and experimental study on the regulation of acoustic metamaterials on sound waves[D].Nanjing:Southeast University, 2019(in Chinese).[10]㊀杨㊀帅,李昌清,赖虹君,等.流固混合声子晶体中负折射与导波特性研究[J].哈尔滨工程大学学报,2022,43(9):1370-1375.YANG S,LI C Q,LAI H J,et al.Study on negative refraction and guided wave characteristics in liquid-solid mixed phononic crystals[J].Journal of Harbin Engineering University,2022,43(9):1370-1375(in Chinese).[11]㊀LIU J,LI L P,XIA B Z,et al.Fractal labyrinthine acoustic metamaterial in planar lattices[J].International Journal of Solids and Structures,2018,132/133:20-30.。

jstd035声学扫描

JOINT INDUSTRY STANDARDAcoustic Microscopy for Non-HermeticEncapsulatedElectronicComponents IPC/JEDEC J-STD-035APRIL1999Supersedes IPC-SM-786 Supersedes IPC-TM-650,2.6.22Notice EIA/JEDEC and IPC Standards and Publications are designed to serve thepublic interest through eliminating misunderstandings between manufacturersand purchasers,facilitating interchangeability and improvement of products,and assisting the purchaser in selecting and obtaining with minimum delaythe proper product for his particular need.Existence of such Standards andPublications shall not in any respect preclude any member or nonmember ofEIA/JEDEC or IPC from manufacturing or selling products not conformingto such Standards and Publications,nor shall the existence of such Standardsand Publications preclude their voluntary use by those other than EIA/JEDECand IPC members,whether the standard is to be used either domestically orinternationally.Recommended Standards and Publications are adopted by EIA/JEDEC andIPC without regard to whether their adoption may involve patents on articles,materials,or processes.By such action,EIA/JEDEC and IPC do not assumeany liability to any patent owner,nor do they assume any obligation whateverto parties adopting the Recommended Standard or ers are alsowholly responsible for protecting themselves against all claims of liabilities forpatent infringement.The material in this joint standard was developed by the EIA/JEDEC JC-14.1Committee on Reliability Test Methods for Packaged Devices and the IPCPlastic Chip Carrier Cracking Task Group(B-10a)The J-STD-035supersedes IPC-TM-650,Test Method2.6.22.For Technical Information Contact:Electronic Industries Alliance/ JEDEC(Joint Electron Device Engineering Council)2500Wilson Boulevard Arlington,V A22201Phone(703)907-7560Fax(703)907-7501IPC2215Sanders Road Northbrook,IL60062-6135 Phone(847)509-9700Fax(847)509-9798Please use the Standard Improvement Form shown at the end of thisdocument.©Copyright1999.The Electronic Industries Alliance,Arlington,Virginia,and IPC,Northbrook,Illinois.All rights reserved under both international and Pan-American copyright conventions.Any copying,scanning or other reproduction of these materials without the prior written consent of the copyright holder is strictly prohibited and constitutes infringement under the Copyright Law of the United States.IPC/JEDEC J-STD-035Acoustic Microscopyfor Non-Hermetic EncapsulatedElectronicComponentsA joint standard developed by the EIA/JEDEC JC-14.1Committee on Reliability Test Methods for Packaged Devices and the B-10a Plastic Chip Carrier Cracking Task Group of IPCUsers of this standard are encouraged to participate in the development of future revisions.Contact:EIA/JEDEC Engineering Department 2500Wilson Boulevard Arlington,V A22201 Phone(703)907-7500 Fax(703)907-7501IPC2215Sanders Road Northbrook,IL60062-6135 Phone(847)509-9700Fax(847)509-9798ASSOCIATION CONNECTINGELECTRONICS INDUSTRIESAcknowledgmentMembers of the Joint IPC-EIA/JEDEC Moisture Classiﬁcation Task Group have worked to develop this document.We would like to thank them for their dedication to this effort.Any Standard involving a complex technology draws material from a vast number of sources.While the principal members of the Joint Moisture Classiﬁcation Working Group are shown below,it is not possible to include all of those who assisted in the evolution of this Standard.To each of them,the mem-bers of the EIA/JEDEC and IPC extend their gratitude.IPC Packaged Electronic Components Committee ChairmanMartin FreedmanAMP,Inc.IPC Plastic Chip Carrier Cracking Task Group,B-10a ChairmanSteven MartellSonoscan,Inc.EIA/JEDEC JC14.1CommitteeChairmanJack McCullenIntel Corp.EIA/JEDEC JC14ChairmanNick LycoudesMotorolaJoint Working Group MembersCharlie Baker,TIChristopher Brigham,Hi/FnRalph Carbone,Hewlett Packard Co. Don Denton,TIMatt Dotty,AmkorMichele J.DiFranza,The Mitre Corp. Leo Feinstein,Allegro Microsystems Inc.Barry Fernelius,Hewlett Packard Co. Chris Fortunko,National Institute of StandardsRobert J.Gregory,CAE Electronics, Inc.Curtis Grosskopf,IBM Corp.Bill Guthrie,IBM Corp.Phil Johnson,Philips Semiconductors Nick Lycoudes,MotorolaSteven R.Martell,Sonoscan Inc. Jack McCullen,Intel Corp.Tom Moore,TIDavid Nicol,Lucent Technologies Inc.Pramod Patel,Advanced Micro Devices Inc.Ramon R.Reglos,XilinxCorazon Reglos,AdaptecGerald Servais,Delphi Delco Electronics SystemsRichard Shook,Lucent Technologies Inc.E.Lon Smith,Lucent Technologies Inc.Randy Walberg,NationalSemiconductor Corp.Charlie Wu,AdaptecEdward Masami Aoki,HewlettPackard LaboratoriesFonda B.Wu,Raytheon Systems Co.Richard W.Boerdner,EJE ResearchVictor J.Brzozowski,NorthropGrumman ES&SDMacushla Chen,Wus Printed CircuitCo.Ltd.Jeffrey C.Colish,Northrop GrummanCorp.Samuel J.Croce,Litton AeroProducts DivisionDerek D-Andrade,Surface MountTechnology CentreRao B.Dayaneni,Hewlett PackardLaboratoriesRodney Dehne,OEM WorldwideJames F.Maguire,Boeing Defense&Space GroupKim Finch,Boeing Defense&SpaceGroupAlelie Funcell,Xilinx Inc.Constantino J.Gonzalez,ACMEMunir Haq,Advanced Micro DevicesInc.Larry A.Hargreaves,DC.ScientiﬁcInc.John T.Hoback,Amoco ChemicalCo.Terence Kern,Axiom Electronics Inc.Connie M.Korth,K-Byte/HibbingManufacturingGabriele Marcantonio,NORTELCharles Martin,Hewlett PackardLaboratoriesRichard W.Max,Alcatel NetworkSystems Inc.Patrick McCluskey,University ofMarylandJames H.Moffitt,Moffitt ConsultingServicesRobert Mulligan,Motorola Inc.James E.Mumby,CibaJohn Northrup,Lockheed MartinCorp.Dominique K.Numakura,LitchﬁeldPrecision ComponentsNitin B.Parekh,Unisys Corp.Bella Poborets,Lucent TechnologiesInc.D.Elaine Pope,Intel Corp.Ray Prasad,Ray Prasad ConsultancyGroupAlbert Puah,Adaptec Inc.William Sepp,Technic Inc.Ralph W.Taylor,Lockheed MartinCorp.Ed R.Tidwell,DSC CommunicationsCorp.Nick Virmani,Naval Research LabKen Warren,Corlund ElectronicsCorp.Yulia B.Zaks,Lucent TechnologiesInc.IPC/JEDEC J-STD-035April1999 iiTable of Contents1SCOPE (1)2DEFINITIONS (1)2.1A-mode (1)2.2B-mode (1)2.3Back-Side Substrate View Area (1)2.4C-mode (1)2.5Through Transmission Mode (2)2.6Die Attach View Area (2)2.7Die Surface View Area (2)2.8Focal Length(FL) (2)2.9Focus Plane (2)2.10Leadframe(L/F)View Area (2)2.11Reﬂective Acoustic Microscope (2)2.12Through Transmission Acoustic Microscope (2)2.13Time-of-Flight(TOF) (3)2.14Top-Side Die Attach Substrate View Area (3)3APPARATUS (3)3.1Reﬂective Acoustic Microscope System (3)3.2Through Transmission AcousticMicroscope System (4)4PROCEDURE (4)4.1Equipment Setup (4)4.2Perform Acoustic Scans..........................................4Appendix A Acoustic Microscopy Defect CheckSheet (6)Appendix B Potential Image Pitfalls (9)Appendix C Some Limitations of AcousticMicroscopy (10)Appendix D Reference Procedure for PresentingApplicable Scanned Data (11)FiguresFigure1Example of A-mode Display (1)Figure2Example of B-mode Display (1)Figure3Example of C-mode Display (2)Figure4Example of Through Transmission Display (2)Figure5Diagram of a Reﬂective Acoustic MicroscopeSystem (3)Figure6Diagram of a Through Transmission AcousticMicroscope System (3)April1999IPC/JEDEC J-STD-035iiiIPC/JEDEC J-STD-035April1999This Page Intentionally Left BlankivApril1999IPC/JEDEC J-STD-035 Acoustic Microscopy for Non-Hermetic EncapsulatedElectronic Components1SCOPEThis test method deﬁnes the procedures for performing acoustic microscopy on non-hermetic encapsulated electronic com-ponents.This method provides users with an acoustic microscopy processﬂow for detecting defects non-destructively in plastic packages while achieving reproducibility.2DEFINITIONS2.1A-mode Acoustic data collected at the smallest X-Y-Z region deﬁned by the limitations of the given acoustic micro-scope.An A-mode display contains amplitude and phase/polarity information as a function of time ofﬂight at a single point in the X-Y plane.See Figure1-Example of A-mode Display.IPC-035-1 Figure1Example of A-mode Display2.2B-mode Acoustic data collected along an X-Z or Y-Z plane versus depth using a reﬂective acoustic microscope.A B-mode scan contains amplitude and phase/polarity information as a function of time ofﬂight at each point along the scan line.A B-mode scan furnishes a two-dimensional(cross-sectional)description along a scan line(X or Y).See Figure2-Example of B-mode Display.IPC-035-2 Figure2Example of B-mode Display(bottom half of picture on left)2.3Back-Side Substrate View Area(Refer to Appendix A,Type IV)The interface between the encapsulant and the back of the substrate within the outer edges of the substrate surface.2.4C-mode Acoustic data collected in an X-Y plane at depth(Z)using a reﬂective acoustic microscope.A C-mode scan contains amplitude and phase/polarity information at each point in the scan plane.A C-mode scan furnishes a two-dimensional(area)image of echoes arising from reﬂections at a particular depth(Z).See Figure3-Example of C-mode Display.1IPC/JEDEC J-STD-035April1999IPC-035-3 Figure3Example of C-mode Display2.5Through Transmission Mode Acoustic data collected in an X-Y plane throughout the depth(Z)using a through trans-mission acoustic microscope.A Through Transmission mode scan contains only amplitude information at each point in the scan plane.A Through Transmission scan furnishes a two-dimensional(area)image of transmitted ultrasound through the complete thickness/depth(Z)of the sample/component.See Figure4-Example of Through Transmission Display.IPC-035-4 Figure4Example of Through Transmission Display2.6Die Attach View Area(Refer to Appendix A,Type II)The interface between the die and the die attach adhesive and/or the die attach adhesive and the die attach substrate.2.7Die Surface View Area(Refer to Appendix A,Type I)The interface between the encapsulant and the active side of the die.2.8Focal Length(FL)The distance in water at which a transducer’s spot size is at a minimum.2.9Focus Plane The X-Y plane at a depth(Z),which the amplitude of the acoustic signal is maximized.2.10Leadframe(L/F)View Area(Refer to Appendix A,Type V)The imaged area which extends from the outer L/F edges of the package to the L/F‘‘tips’’(wedge bond/stitch bond region of the innermost portion of the L/F.)2.11Reflective Acoustic Microscope An acoustic microscope that uses one transducer as both the pulser and receiver. (This is also known as a pulse/echo system.)See Figure5-Diagram of a Reﬂective Acoustic Microscope System.2.12Through Transmission Acoustic Microscope An acoustic microscope that transmits ultrasound completely through the sample from a sending transducer to a receiver on the opposite side.See Figure6-Diagram of a Through Transmis-sion Acoustic Microscope System.2April1999IPC/JEDEC J-STD-0353IPC/JEDEC J-STD-035April1999 3.1.6A broad band acoustic transducer with a center frequency in the range of10to200MHz for subsurface imaging.3.2Through Transmission Acoustic Microscope System(see Figure6)comprised of:3.2.1Items3.1.1to3.1.6above3.2.2Ultrasonic pulser(can be a pulser/receiver as in3.1.1)3.2.3Separate receiving transducer or ultrasonic detection system3.3Reference packages or standards,including packages with delamination and packages without delamination,for use during equipment setup.3.4Sample holder for pre-positioning samples.The holder should keep the samples from moving during the scan and maintain planarity.4PROCEDUREThis procedure is generic to all acoustic microscopes.For operational details related to this procedure that apply to a spe-ciﬁc model of acoustic microscope,consult the manufacturer’s operational manual.4.1Equipment Setup4.1.1Select the transducer with the highest useable ultrasonic frequency,subject to the limitations imposed by the media thickness and acoustic characteristics,package conﬁguration,and transducer availability,to analyze the interfaces of inter-est.The transducer selected should have a low enough frequency to provide a clear signal from the interface of interest.The transducer should have a high enough frequency to delineate the interface of interest.Note:Through transmission mode may require a lower frequency and/or longer focal length than reﬂective mode.Through transmission is effective for the initial inspection of components to determine if defects are present.4.1.2Verify setup with the reference packages or standards(see3.3above)and settings that are appropriate for the trans-ducer chosen in4.1.1to ensure that the critical parameters at the interface of interest correlate to the reference standard uti-lized.4.1.3Place units in the sample holder in the coupling medium such that the upper surface of each unit is parallel with the scanning plane of the acoustic transducer.Sweep air bubbles away from the unit surface and from the bottom of the trans-ducer head.4.1.4At aﬁxed distance(Z),align the transducer and/or stage for the maximum reﬂected amplitude from the top surface of the sample.The transducer must be perpendicular to the sample surface.4.1.5Focus by maximizing the amplitude,in the A-mode display,of the reﬂection from the interface designated for imag-ing.This is done by adjusting the Z-axis distance between the transducer and the sample.4.2Perform Acoustic Scans4.2.1Inspect the acoustic image(s)for any anomalies,verify that the anomaly is a package defect or an artifact of the imaging process,and record the results.(See Appendix A for an example of a check sheet that may be used.)To determine if an anomaly is a package defect or an artifact of the imaging process it is recommended to analyze the A-mode display at the location of the anomaly.4.2.2Consider potential pitfalls in image interpretation listed in,but not limited to,Appendix B and some of the limita-tions of acoustic microscopy listed in,but not limited to,Appendix C.If necessary,make adjustments to the equipment setup to optimize the results and rescan.4April1999IPC/JEDEC J-STD-035 4.2.3Evaluate the acoustic images using the failure criteria speciﬁed in other appropriate documents,such as J-STD-020.4.2.4Record the images and theﬁnal instrument setup parameters for documentation purposes.An example checklist is shown in Appendix D.5IPC/JEDEC J-STD-035April19996April1999IPC/JEDEC J-STD-035Appendix AAcoustic Microscopy Defect Check Sheet(continued)CIRCUIT SIDE SCANImage File Name/PathDelamination(Type I)Die Circuit Surface/Encapsulant Number Affected:Average%Location:Corner Edge Center (Type II)Die/Die Attach Number Affected:Average%Location:Corner Edge Center (Type III)Encapsulant/Substrate Number Affected:Average%Location:Corner Edge Center (Type V)Interconnect tip Number Affected:Average%Interconnect Number Affected:Max.%Length(Type VI)Intra-Laminate Number Affected:Average%Location:Corner Edge Center Comments:CracksAre cracks present:Yes NoIf yes:Do any cracks intersect:bond wire ball bond wedge bond tab bump tab leadDoes crack extend from leadﬁnger to any other internal feature:Yes NoDoes crack extend more than two-thirds the distance from any internal feature to the external surfaceof the package:Yes NoAdditional veriﬁcation required:Yes NoComments:Mold Compound VoidsAre voids present:Yes NoIf yes:Approx.size Location(if multiple voids,use comment section)Do any voids intersect:bond wire ball bond wedge bond tab bump tab lead Additional veriﬁcation required:Yes NoComments:7IPC/JEDEC J-STD-035April1999Appendix AAcoustic Microscopy Defect Check Sheet(continued)NON-CIRCUIT SIDE SCANImage File Name/PathDelamination(Type IV)Encapsulant/Substrate Number Affected:Average%Location:Corner Edge Center (Type II)Substrate/Die Attach Number Affected:Average%Location:Corner Edge Center (Type V)Interconnect Number Affected:Max.%LengthLocation:Corner Edge Center (Type VI)Intra-Laminate Number Affected:Average%Location:Corner Edge Center (Type VII)Heat Spreader Number Affected:Average%Location:Corner Edge Center Additional veriﬁcation required:Yes NoComments:CracksAre cracks present:Yes NoIf yes:Does crack extend more than two-thirds the distance from any internal feature to the external surfaceof the package:Yes NoAdditional veriﬁcation required:Yes NoComments:Mold Compound VoidsAre voids present:Yes NoIf yes:Approx.size Location(if multiple voids,use comment section)Additional veriﬁcation required:Yes NoComments:8Appendix BPotential Image PitfallsOBSERV ATIONS CAUSES/COMMENTSUnexplained loss of front surface signal Gain setting too lowSymbolization on package surfaceEjector pin knockoutsPin1and other mold marksDust,air bubbles,ﬁngerprints,residueScratches,scribe marks,pencil marksCambered package edgeUnexplained loss of subsurface signal Gain setting too lowTransducer frequency too highAcoustically absorbent(rubbery)ﬁllerLarge mold compound voidsPorosity/high concentration of small voidsAngled cracks in package‘‘Dark line boundary’’(phase cancellation)Burned molding compound(ESD/EOS damage)False or spotty indication of delamination Low acoustic impedance coating(polyimide,gel)Focus errorIncorrect delamination gate setupMultilayer interference effectsFalse indication of adhesion Gain set too high(saturation)Incorrect delamination gate setupFocus errorOverlap of front surface and subsurface echoes(transducerfrequency too low)Fluidﬁlling delamination areasApparent voiding around die edge Reﬂection from wire loopsIncorrect setting of void gateGraded intensity Die tilt or lead frame deformation Sample tiltApril1999IPC/JEDEC J-STD-0359Appendix CSome Limitations of Acoustic MicroscopyAcoustic microscopy is an analytical technique that provides a non-destructive method for examining plastic encapsulated components for the existence of delaminations,cracks,and voids.This technique has limitations that include the following: LIMITATION REASONAcoustic microscopy has difficulty inﬁnding small defects if the package is too thick.The ultrasonic signal becomes more attenuated as a function of two factors:the depth into the package and the transducer fre-quency.The greater the depth,the greater the attenuation.Simi-larly,the higher the transducer frequency,the greater the attenu-ation as a function of depth.There are limitations on the Z-axis(axial)resolu-tion.This is a function of the transducer frequency.The higher the transducer frequency,the better the resolution.However,the higher frequency signal becomes attenuated more quickly as a function of depth.There are limitations on the X-Y(lateral)resolu-tion.The X-Y(lateral)resolution is a function of a number of differ-ent variables including:•Transducer characteristics,including frequency,element diam-eter,and focal length•Absorption and scattering of acoustic waves as a function of the sample material•Electromechanical properties of the X-Y stageIrregularly shaped packages are difficult to analyze.The technique requires some kind ofﬂat reference surface.Typically,the upper surface of the package or the die surfacecan be used as references.In some packages,cambered packageedges can cause difficulty in analyzing defects near the edgesand below their surfaces.Edge Effect The edges cause difficulty in analyzing defects near the edge ofany internal features.IPC/JEDEC J-STD-035April1999 10April1999IPC/JEDEC J-STD-035Appendix DReference Procedure for Presenting Applicable Scanned DataMost of the settings described may be captured as a default for the particular supplier/product with speciﬁc changes recorded on a sample or lot basis.Setup Conﬁguration(Digital Setup File Name and Contents)Calibration Procedure and Calibration/Reference Standards usedTransducerManufacturerModelCenter frequencySerial numberElement diameterFocal length in waterScan SetupScan area(X-Y dimensions)Scan step sizeHorizontalVerticalDisplayed resolutionHorizontalVerticalScan speedPulser/Receiver SettingsGainBandwidthPulseEnergyRepetition rateReceiver attenuationDampingFilterEcho amplitudePulse Analyzer SettingsFront surface gate delay relative to trigger pulseSubsurface gate(if used)High passﬁlterDetection threshold for positive oscillation,negative oscillationA/D settingsSampling rateOffset settingPer Sample SettingsSample orientation(top or bottom(ﬂipped)view and location of pin1or some other distinguishing characteristic) Focus(point,depth,interface)Reference planeNon-default parametersSample identiﬁcation information to uniquely distinguish it from others in the same group11IPC/JEDEC J-STD-035April1999Appendix DReference Procedure for Presenting Applicable Scanned Data(continued) Reference Procedure for Presenting Scanned DataImageﬁle types and namesGray scale and color image legend deﬁnitionsSigniﬁcance of colorsIndications or deﬁnition of delaminationImage dimensionsDepth scale of TOFDeviation from true aspect ratioImage type:A-mode,B-mode,C-mode,TOF,Through TransmissionA-mode waveforms should be provided for points of interest,such as delaminated areas.In addition,an A-mode image should be provided for a bonded area as a control.12Standard Improvement FormIPC/JEDEC J-STD-035The purpose of this form is to provide the Technical Committee of IPC with input from the industry regarding usage of the subject standard.Individuals or companies are invited to submit comments to IPC.All comments will be collected and dispersed to the appropriate committee(s).If you can provide input,please complete this form and return to:IPC2215Sanders RoadNorthbrook,IL 60062-6135Fax 847509.97981.I recommend changes to the following:Requirement,paragraph number Test Method number,paragraph numberThe referenced paragraph number has proven to be:Unclear Too RigidInErrorOther2.Recommendations forcorrection:3.Other suggestions for document improvement:Submitted by:Name Telephone Company E-mailAddress City/State/ZipDate ASSOCIATION CONNECTING ELECTRONICS INDUSTRIESASSOCIATION CONNECTINGELECTRONICS INDUSTRIESISBN#1-580982-28-X2215 Sanders Road, Northbrook, IL 60062-6135Tel. 847.509.9700 Fax 847.509.9798。

水下圆柱壳低频声辐射特性及有源控制

水下圆柱壳低频声辐射特性及有源控制丁少虎;陈克安;李双【摘要】The radiation characteristics of a submerged finite cylindrical shell at low frequencies were investigated based on its vibration modes and acoustic radiation modes.The contribution of each circumferential vibration mode to the radiated sound was observed.Then,under a certain circumferential mode,axial vibration modes were divided into an axial odd-mode group and an axial even-mode group,and the correspondance relationships between each vibration mode group and acoustic radiation modes at low frequency were inspected.The results show that at low frequencies,only the first few circumferential vibration modes contribute to the sound power radiated from a submerged finite cylindrical shell excited by radial point forces;under a certain circumferential mode,the sound power radiated by the odd (even)axial vibration modes group corresponds to the acoustic radiation mode with the same circumferential mode and even (odd) axial modes.The sound power radiated from a submerged finite cylindrical shell can be restrained by controlling the sound power of the dominant radiation modes.%利用振动模态及声辐射模态分析水下有限长圆柱壳低频模态辐射特性。

Structural Health Monitoring and Control

Structural Health Monitoring and Control Structural health monitoring and control play a critical role in ensuring the safety and longevity of infrastructure such as bridges, buildings, and pipelines. This field involves the use of various sensing technologies to continuously monitor the condition of structures, detect damage or deterioration, and provide real-time data for decision-making. Additionally, structural control systems can be implemented to actively mitigate the effects of external forces or environmental conditions on the structure, thereby enhancing its overall performance and resilience. From a technical perspective, structural health monitoring encompasses a wide range of sensor technologies, including strain gauges, accelerometers, acoustic emission sensors, and non-destructive testing methods such as ultrasound and thermography. These sensors are strategically deployed throughout the structure to capture data on parameters such as strain, vibration, temperature, and corrosion. The data collected from these sensors are then processed and analyzed using advanced algorithms to assess the structural integrity, identify potential issues, and predict the remaining useful life of the infrastructure. Moreover, the integration of structural control systems, such as active vibration control and structural damping devices, allows for the active management of structural response to dynamic loads, thereby reducing the risk of fatigue and failure. These control systems can be designed to adapt to changing environmental conditions and external forces, providing an additional layer of protection for the structure. The combination of monitoring and control technologies offers a comprehensive approach to ensuring the structural safety and reliability of critical infrastructure. Beyond the technical aspects, the importance of structural health monitoring and control extends to broader societal and economic implications. The failure of infrastructure can have devastating consequences, leading to loss of life, disruption of essential services, and significant economic costs. By proactively monitoring and controlling the healthof structures, we can minimize the risks associated with structural failures and ensure the safety and well-being of communities. Furthermore, the implementation of structural health monitoring and control technologies aligns withsustainability and resilience goals, as it enables the optimization of maintenancepractices and the extension of the service life of infrastructure. This, in turn, contributes to the efficient use of resources and reduction of environmental impact associated with the construction and replacement of infrastructure. By embracing these technologies, we can build more sustainable and resilient communities for the future. In conclusion, structural health monitoring and control are indispensable for ensuring the safety, reliability, and longevity of infrastructure. The integration of advanced sensor technologies, data analytics, and structural control systems offers a holistic approach to managing the health of structures, with far-reaching implications for safety, sustainability, and resilience. Embracing these technologies is essential for safeguarding our built environment and ensuring a secure future for generations to come.。

英汉词典

接合座自适应总线-digital data highway to which(almost) any number of inputs 地址-electronic code identifying each part of computer memory,each address bit or information unit being routed to different address adhesion 粘接 adhesive tape 粘胶带 adjacent to 邻近的可调水平安定面-horizontal stabilizer of an airplane which may be adjustable stabilizer adjusted in flight to trim the airplane for hands-off mode in flight admittance 导纳-in AC circui,reciprocal of impedance advance drawing 图纸先行更改通知 change notice(ADCN) advanced 先进的-new sophisticated and typifying latest technology advanced switch 步进电门 adverse effect 不利影响；严重后果 advisory circular(AC) 咨询通报 advisory Message 咨询信息 aerodynamic 空气动力的 aerodynamic smoother 空气动力平滑胶 aeroelastic torsion 气动弹性扭曲 aeronautical 航空的 aerosol 烟雾，浮质-colloid of finely divided solid or liquid disperesed in aft looking forward 从后向前看 afterbody drag 后体阻力 afterburner 加力燃烧室尾喷管喷火-sometimes called torching,a condition resulting from afterfiring unburrnt fuel being ignited in the exhaust nozzle age-hardening 时效，硬化 ageing=aging 时效处理 aging 老龄的 agent 试剂 aileron 付翼 aileron authority 付翼效能付翼传动力限制器-electro-mechanical device for limiting the control aileron force limiter wheel movement by the autopilot during autopilot operation aileron programmer 付翼程序器-convert central lateral control actuator motion to control air bleed valve 放气活门减速板；阻力板-a plate or series of plates that may be projected into air brake airport's slipstream to provide turbulence and drag to slow the air carrier 航空营运者-any company which provides commercial air transportation air conditioning 空调空气循环机；涡轮冷却器-a compressor & turbine on a common shaft for air cycle machine cooling air in an air conditioning system 大气数据计算机-one which produces air data air data computer information(altitude,airspeed ect) based on pressure and temperature 中断飞行-a change from original flight plan due to a known or air interruption suspected malfunction&/ defect during flight air lock 气锁，气塞-a trapped pocket of air that blocks the flow of fluid 空气封严件；气密封圈；气封严-usually thin rotating or staionary rims air seal designed to act as air DAMS to reduce airflow leakage air ground 起落架位置传感器；空地传感器-an electrical device operated by the sensor landing gear for transmitting airport position for systems operation air tapping 抽气管座空中返航-return of airplane to airplane of origin as a result of air turnback malfunction or suspected defect of any item on airplane airborne 空中飞行的；机载的

风电常用英语词..

风电项目常用英语词汇tubular tower 塔筒式塔架lattice tower 桁架式塔架nacelle 机舱gearbox 齿轮箱rotor shaft 转轴generator 发电机yaw base 偏航基座、偏航盘yaw gear 偏航齿轮asynchronous generator 异步发电机turbine 涡轮hub 轮毂grid 电网blade 叶片diameter 直径area swept 扫掠面积speed of revolution 旋转速度operational interval 转速变化范围power regulation 功率调节air brake 空气制动cut-in speed 切入风速nominal wind speed 额定风速cut-out speed 切出风速stop wind speed 停止风速hub controller 轮毂控制器pitch cylinder 桨距调节气缸blade hub 叶片轮毂blade bearing 叶片轴承main shaft 主轴oil cooler 油冷却器parking brake 制动装置service crane 维护吊车transformer 变压器yaw 偏航revolution 旋转anemometer 测风仪vane 风向标planet/parallel axles 行星/平行轴microprocessor 微处理器pitch regulation 桨距调节synchronous 同步的asynchronous 异步的foundation 基础wind turbine generating 风力发电机组power performance 功率特性off-grid 离网grid connected 并网acoustic noise 噪声diameter直径epoxy. 环氧的beam. 梁pitch angle. 桨距角perpendicular正交的humidity 湿度operational interval 转速变化范围corrosion腐蚀cable 电缆grid dropout掉网earthing接地terrain 地形anchor 锚moisture 潮湿pickling 酸洗rinsing 清洗circumferential 圆柱的longitudinal 经度的proportionate 成比例的zinc 锌，涂锌于micron 微米quench 淬火armature 电枢slewing 定位girder 梁，支架polyurethane 聚亚安酯boom 上升luffing 上下摆动counterweight 平衡物sleeper 枕木miscellaneous 混杂的，各式各样的gear box 齿轮箱capacitor 电容reactive power 无功功率lag 滞后FIFO 先进先出Switch cabinet 开关盒Slip 滑动Slewing 定位Aerodynamically 空气动力splash-type lubricating system. 飞溅润滑reduction gearbox 减速箱untwist the cables 电缆解绕jib 臂stator 定子stall 失速upwind 上风向downwind 下风向active stall power control 主动失速控制alternating current (AC) 交流电azimuth angle 方位角Betz' law 贝茨定律dB (A), decibel (A) scale 分贝delta connection Δ连接density of air 空气密度direct grid connection 直接并网efficiency 效率energy balance 能量平衡extreme load 极端负荷fatigue load 疲劳负荷flange 法兰grid frequency 电网频率gust 阵风horizontal axis wind turbine (HAWT) 水平轴风力机hub height 轮毂高度hydraulics system 液压系统Hz (Hertz) Hzinduction generator 感应电机Installation 安装Obstacle 障碍offshore wind energy 海上风能pitch control 桨距控制pole changing generator 变极发电机power curve 功率曲线Rated power, nameplate power 额定功率，铭牌功率Rectifier 整流器renewable energy 可再生能源Roughness 粗糙度site, siting 现场，选址soft start 软起动speed up effect 加速Stall 失速stall control 失速控制star connection 星形连接Stator 定子structural dynamics 结构动力学Three phase alternating current 三相交流电turbulence 紊流(rotor blade) twist 扭曲叶片vertical axis wind turbine (V AWT) 垂直轴风轮机yaw mechanism 偏航装置风电词汇中英文对照表-I abrasive研磨料abrasive disc磨料盘accumulator 储压罐acetone丙酮activation活动，赋活，激活，活化，激励，启用acute angle锐角adhesive 带粘性的, 胶粘, 粘合剂adjustable spanner 活动扳手admixture 混合, 混合物adversely逆地, 反对地adze扁斧aerial航空的, 生活在空气中的, 空气的, 高耸的,天线aerosol 浮质,气溶胶, 气雾剂, 烟雾剂aggregate 合计, 总计, 集合体aggressively 侵略地, 攻势地air inlet通风口air-cushion vehicle气垫船air gap气隙align对准，校直，定位；调,排列, 使结盟, 使成一行alkali-sensitive碱性感测allen key 六方allen wrench 六方扳手alloy 合金alteration变更, 改造alternator 交替符；交流发电机ammeter安培计，电流表anaerobic没有空气而能生活的, 厌氧性的anchor 锚, 抛锚, 锚定aneroid barometer无液气压表, 无液晴雨angle grinder角锉angle plate角盘annealing 退火annulus环面anode阳极, 正极anodization阳极氧化antenna 天线；触角antifriction减低或防止磨擦之物, 润滑剂anvil铁砧approximate近似, 接近, 约计 adjarbor 树阴；凉亭；藤架〈机〉柄轴；心轴arc 弧, 弓形, 拱,电弧arc welding 电弧焊archimedean screw阿基米德螺线arrmature 电枢articulated接合,链接,有关节的assemble集合, 聚集, 装配assorted files分类排列；相匹配(文件)assume假定, 设想, 采取, 呈现attenuation变薄, 稀薄化, 变细, 衰减auger打孔钻，螺丝钻averagen. 平均, 平均水平, 平均数, 海损, 一般的, 通常的awln锥子axe斧, (经费的)大削减axle. 轮轴, 车轴Bback saw背锯backlash反冲，无效行程；间隙，偏移；退ball bearing滚珠轴ball saddle滚珠支撑ball-peen hammerband区；带，波段带子, 镶边, 波段, 队, 乐队. 联合, 结合bandsaw用带锯锯bar magnet磁条barometer气压计；晴雨表battery power drill电池钻beach海滨；湖滨；河滩bead 珠子, 水珠beam compass长臂圆规beam trammel骨架bearer 支架，托架，支座，载体bell crank曲柄belting制带的材料, 带类, 调带装置bessemer酸性转炉钢bessemer converter . 酸性转炉,贝塞麦转炉bevel gear斜角；斜齿轮bevel-edge shisel斜缘薄钢板biconcave lens两面凹镜biconvex lens两面凸镜bifurcated rivetbimetallic双金属的bin二进制；双态bit 位, 比特blade for iron saw剧刃blast 强风，过载blast furnace鼓风炉blast cleaning皮老虎bleed 放出(液体，气体等)；漏出，漏入，泄漏，色料扩散bleeder valve 溢流阀block and tackle滑轮组blowlamp喷灯blowpipe吹风管blowtorch 吹管, 喷灯board 底板，板boiler锅炉；煮器；烧水器bolt螺栓，螺钉，支持，维持bone 骨剔除bonnet软帽,汽车发动机罩bore钻孔,钻bottom dead-centrebow-spring compassbox spanner管钳子box spanner insetbrac支柱, 带子, 振作精神bracket托架, 括弧, 支架brad曲头钉bradawl小锥Brakebrake lining闸, 刹车的衬里, 内层, 衬套brake shoe 闸轨branch of joint连接分支brass黄铜, 黄铜制品,brazing铜焊breast drillbreather 呼吸者, 喘息者, 剧烈的运动bricklayer's hammerbubble 磁泡，水泡，气泡bucket桶, 一桶的量, 铲斗Buffing wheelbulk大小, 体积, 大批, 大多数, 散装bulkhead隔壁, 防水壁bulldozer 推土机bunsen burner 本生灯burr芒刺；刺果植物；针球burstn. 突然破裂, 爆发, 脉冲bursting discbush 矮树丛, (机械)衬套bushing轴衬, 套管Ccabinet screw drivercable bundle 束，光纤束；捆，卷cable reel电缆盘cable shear电缆剪cable shoes电缆靴cable tie电缆带calibration标度, 刻度, 校准caliper测径器, 卡钳, 弯脚器cam凸轮camber 拱形camshaft凸轮轴cantilever伸臂，悬臂；悬臂梁cap帽,罩cap nut螺冒capaciron电容汞弧管capacitance电容；电容量capstan lathe绞盘车床carburettor 汽化器cardan shaft万向轴cartridge额盒式磁盘[带](机)；夹头cast投；掷；抛casting. 铸件, 铸造castle nut城堡螺母catalyst 催化剂，触媒cathode 阴极cathode-ray tube阴极射线管catwalk桥上人行道, 狭小通道caulking 填...以防漏caution小心, 谨慎, 警告cement 水泥, 接合剂, 接合, 用水泥涂, 巩固, 粘牢center puncher中心冲centre bit中心位centrifugal离心centrifugal unit离心单元ceramics 陶瓷；陶瓷技术chain vice链式钳chain wheel 滑轮chain-grate stoker链条炉排加煤机change over 改变成,对调位chaser猎人, 驱逐舰cheese 干酪,垫砖cheese-head screw 有槽凸圆柱头螺钉chisel 凿子砍凿chloride氯化物,漂白粉choke窒息, 阻气门choke valve阻气阀chord弦, 和音, 情绪chrome 铬；铬矿石；氧化铬chuck. 轻拍, 抛掷, 驱逐, 丢弃, 用卡盘夹住circlip环形circular圆形，环；循环circular saw圆锯circulate 循环；流通circulating循环, 流通circumference周线；外围；周围clamp夹子, 夹具, 夹钳clamp ammeter钳形表claw hammer 拔钉锤clearancen清理，清除；出空,间空，间隔；距离cleat夹板clog填塞；塞满close grainedclout nail大帽钉club hammer锤子，榔头clutch离合器，联轴器coarse粗(糙，略)，近似cobalt钴(符号为Co), 钴类颜料, 由钴制的深蓝色coil线圈，绕组coil spring弹圈collar 凸缘；圈，环，套环，轴；卡圈；安装环collar bolt凸缘螺栓combination结合, 联合, 合并, 化合, 化合物combination pliers台钳combustion chamber燃烧室compound 混合物, [化]化合物复合的, 混合, 配合compresso压缩物, 压缩机, 收缩肌comutator 换向器, 转接器concave len凹面镜concave-convex len凸凹镜concrete混凝土；具体concrete drill混凝土钻condenser冷凝器；凝结器，电容器conduit管道, 导管, 沟渠, 泉水, 喷泉cone数、物]锥形物, 圆锥体, (松树的)球果, 使成锥形cone and cup unionconical 圆锥的, 圆锥形的conjunction联合, 关联, 连接词connecting rod连接杆considerably 相当地consistency连结, 结合, 坚固性, 浓度, 密度, 一致性, 连贯性console 安慰, 藉慰,控制台container箱；罐；容器集装箱，货柜contaminate污染，弄污contrast使与...对比, 使与...对照, 和...形成对照, 对比, 对照, (对照中的) Controlconvection传送；运流；对流converter换流器；变换器；变流器convex lens凸透镜cooling冷却；冷却技术core sandcorrespond符合, 协调, 通信, 相当, 相应corrosion腐蚀，浸蚀cotter pincountersink bit装定位countersunk埋头孔, 暗钉眼countersunk rivetcountersunk-head screwcounting计算coupling bolt 联结, 接合, 耦合，耦合性，耦合技术coverage 覆盖；敷层；有效区域crack 裂纹，裂缝cramp 钳位(电路)；压[夹板]；卡子，夹(子)；压[夹]紧crane起重机crank不稳定的，摇晃的,曲柄crankcase曲柄轴箱crankshaft曲轴；机轴criterion标准,判据,准则cross mark十字标记cross slotted screw十字长孔crosshead 小标题, 子题, [机]十字头, 丁字头cross-peen hammer 横头锤cross-section横断面；横切面；截面crosswise斜地, 成十字状地, 交叉地crowbar撬棍；铁棍；起货钩crown wheel 顶圈crucible坩锅, 严酷的考验cupola furnace园顶熔炉current ration电流定值customs 进口税, 海关cutter刀具, 切割机cutting disk切割盘cylinder block缸体cylinder head缸头cylinder-head gasket缸头垫片，垫圈；接合垫cylindrical圆柱形，圆柱体；柱面Ddampen使潮湿, 使沮丧damper风门；节气阀darwing board画图板deactivate释放；去激励；停用；退出工作；使无效debris碎片, 残骸decimal 十进的, 小数的,小数defective有缺陷的,欠缺的deflect (使)偏斜, (使)偏转deflection偏向；偏斜；转向deformation 变形，形变；畸变，失真degrease脱脂, 除油污degree celsius摄氏度deploy展开, 配置deposit 堆积物, 沉淀物, 存款, 押金, 保证金, 存放物depress使沮丧, 使消沉, 压下, 压低depression 沮丧, 消沉, 低气压, 低压depressurizes 使减压, 使降压depth gauge深度计detergent 清洁剂, 去垢剂deviation 偏差，偏移dial gauge量规dial micrometer千分尺dielectric 电介质, 绝缘体diestock螺丝攻differential gear差速齿轮differential protection差动保护diffuser 漫射体；(扬声器)纸盆；扩散器digger挖掘者挖掘机digital clock数字钟digitizing tablet数字面板dilute 冲淡, 变淡, 变弱, 稀释discharge 卸下, 放出, 清偿(债务), 履行(义务), 解雇, 开(炮), 放(枪), 射(箭). 卸货, 流注, 放电dismantle拆除，拆卸dismount 拆卸，卸下disposal 处理, 处置, 布置, 安排, 配置, 支配dissipation 分散, 浪费, 损耗，耗散，消耗distance ring间隔环distributor发行人,分电盘,配电器dividers圆规double phase两相dog clutchdolly洋娃娃 ,移动车,台车,,移动摄影车domed nut 圆顶螺母doubt不确定；疑惑dowel 木钉, 销子, 用暗销接合drain排水沟, 消耗, 排水drain tap排气阀draw bar绘图刀drawing pin图钉drawing point绘图点drift 漂移，偏差drill 训练, 钻孔, 条播, 钻头；锥子；钻孔机；钻床；钻drill gauge钻规driller 钻孔者, 钻孔机drilling machine 钻床drip pan油滴盘drop hammer落锤drum鼓, 鼓声drum brake鼓状刹车dryness干, 干燥duplex双(向，重)，双工，二重durability 耐久性，耐用性duration宽度，持续时间dust 灰尘, 尘土, 尘埃dynamo 发电机dynamometer 测力计, 功率计Eearthmover 重型推土机eccentric古怪的；偏执的不同圆心的,离心的；不正圆的edge刀口, 利刃, 锋, 优势, 边缘, 优势, 尖锐elbow机械肘, 肘electric furnace电熔炉electric plier电气钳electric screw driver电钻electric welding电焊electricalelectrode 电极electrolysis 电解，电蚀electrolyte电解, 电解液electroplating 电镀, 电镀术eliminate消除，删去，排除；切断emery 金刚砂, 刚玉砂emery cloth砂布,金刚砂布emery wheel. 金刚砂旋转磨石, 砂轮endplate终板endwise末端朝前或向上的,向前的energizing使活跃, 给予精力, 加强, 给与...电压激励，赋能；接通epicyclic gear计数齿epoxy 环氧树脂epoxy-glued环氧胶equilateral triangle 等边三角形erection直立, 竖起, 建筑物errorexectric arc电弧exhaust pipe 排气管exhaust valve排气阀expanded metal膨胀金属expander扩展器，扩展电路，扩大器expansion bolt自攻螺丝explanatory quad填充铅块extension tube伸缩管extern外(面)的, 外来的external callipers外卡钳extrusion 挤压，挤压成形eye bolt吊耳eye screw螺丝眼Ffabrication 制造；生产；结构faceplate面板, 花盘facilitate使容易, 使便利, 推动, 帮助, 使容易, 促进fag bolt, 疲劳螺栓fake假货, 欺骗, 伪造, 赝造, 捏造, 假造, 仿造fan belt风扇皮带fan heate风扇加热器feeler gauge触规felling axe外轮轴fetch 接来, 取来, 带来, 售得, 引出, 吸引, 到达, 演绎出filament灯丝；细丝fire extinguisher灭火器firebrick 耐火砖fireman's axe消防斧firmer chisel . 凿子flange 边缘, 轮缘, 凸缘, 法兰flange coupling凸缘联轴器flanged nut凸缘螺母flanged union凸缘连接flank侧面, 军队侧翼, 侧腹, 胁flash welding 闪光焊flashlight 手电筒, 闪光灯flashpoint闪点flat 平坦的, 扁平的, 单调的, 倒下的, 浅的flat nut平螺母flat-head rivet平头铆钉flaw裂缝，缺陷，疵瑕flex弯曲(四肢), 伸缩, 折曲flexure 弯曲，挠曲float chamber浮子floating. 漂浮的, 浮动的, 移动的, 流动的, 不固定的flue烟洞, 烟道, 暖气管, 蓬松的东西flush刷新flux 磁通，通量；焊剂；流动, 熔化, 流出footpump脚泵forge炼炉；熔炉fork 派生(指令)，分叉(指令)，分支fork-lift truck叉架式运货车,铲车formation 构造，结构；形成，建立；形式forming印版foundry铸造, 翻砂, 铸工厂, 玻璃厂, 铸造厂foundation 基础, 根本, 建立, 创立, 地基,four-jaw chuck四爪卡盘four-stroke四冲程frame帧，画面；框架机架，架，机柜fret-saw线剧friction 摩擦, 摩擦力friction grip摩擦盘frictional摩擦的, 摩擦力的frost霜, 霜冻, 严寒, 结霜funnel 漏斗, 烟窗furnace炉子, 熔炉furnish 供应, 提供, 装备, 布置Ggale强风，大风galvanizing. 通电流于, 电镀gang saw 直锯gas burner. 煤气灶, 煤气火焰gas main. 煤气总管gas mask防毒面具gas pedal气体, 煤气, 毒气, 汽油, 瓦斯gas turbine 燃气涡轮gas well 天然气井gas works煤气厂gasket垫片，垫圈；接合垫gaskets垫片，垫圈；接合垫gasometer煤气厂, 气量计gate pole门极gate valve门阀gauge标准尺, 规格, 量规, 量表, 测量gavel 槌gear lever 变速杆gear train齿轮系gear wheel齿轮geiger counter盖格计数器gel-coated胶衣gimbals 平衡环，平衡架gimlet手钻；螺丝锥girder 梁, 钢桁的支架girder bridgegland腺,密封管glass cutter玻璃刀glaze釉料, 釉面, 光滑面, 上釉, 上光globe valve球形阀gloss注释；注解；评注, 光泽的表面, 光彩, 欺人的表面, 假象, gloss paint光滑涂料glossy 平滑的, 有光泽的glove手套glue胶, 胶水, 胶合, 粘贴, 粘合goggle 眼睛睁视, (复数)风镜, 护目镜gold leaf金叶goons细打包麻布gouge弧口凿，半圆凿governor 调节器；控制器grab 抢夺, 攫取, 夺取grader 分类机,分级机grain 颗粒，晶粒，粒度；纹理graph 图表, 曲线图grease油膏；润滑油grease gun注油枪；滑脂枪grease nipple油管grinding磨的, 磨擦的, 碾的grinding disk 磨擦盘grinding machine磨床grinding wheel 砂轮groove凹槽, 惯例, 最佳状态grout. 薄泥浆, 水泥浆grouting给…灌灰浆，给…涂薄胶泥grub screw自攻螺丝guide bars导向棍guide block导向块guide ring导向绳guiding shaft导向轴guillotine闸刀,处斩刑, 切(纸)gumming树胶分泌gyroscope 陀螺仪, 回旋装置, 回转仪, 纵舵调整器Hhacksaw可锯金属的弓形锯, 钢锯hairspring细弹簧, 游丝half shaft半轴half-round file半圆锉halfway中途的, 部分的, 不彻底的,半路地,在中途, 在半途handling 处理(技术，方法)hanging顶端对齐，悬挂hardener 固化剂，硬化剂harder硬的, 坚固的, (问题, 工作等)困难的,艰苦的, 猛烈的, 确实的harness导线，装备；利用harrow耙hatch, 舱口, 舱口盖,开口,. 孵, 孵出,策划, 图谋hatchet. 短柄斧hazard 冒险(性)；相关危险；事故，故障headscrew主轴螺杆headstock主轴箱helical gearing螺旋齿helix. 螺旋, 螺旋状物hemp 大麻, 纤维hereafter. 今后, 从此以后herring-bone gearhexagon screw diehexagon spanner六方hexagonal nut六角螺母hightensile 高强度high-tension cable高压电缆hissing发嘶嘶声, 蔑视hob滚刀, 铁架hoe 锄头,用锄耕地, 锄hoist升起；吊起；推起, 起重机,(台、架等)支持物, 固定器hollow空的，中空的hook bolt吊耳hook spanner 钩,弯脚扳手hook's jointhopper. 单足跳者horizontal地平线的, 水平的horseshoe magnet马蹄形磁铁hose 软管，胶皮管，蛇管hose clip管夹hot-dip热沾hottest. 热的,热烈的housing住房，房屋,护盖，框架hovercraft 水翼船hub rigidity轮毂刚度hubcap. 轮毂罩hull外壳, 船体humidity湿气, 潮湿, 湿度hydraulic水压的；液压的hydraulic block液压块hydraulic ram液压活塞hygrographs 自动湿度记录计hygrometer湿度计hysteresis. 滞后作用, [物]磁滞现象Ii-beamidler gear惰轮齿idler pulley惰轮,空转轮,导轮idling 空载，无载impeller 推进者, 叶轮impinge 撞击，冲击imprint 印记imprison监禁, 关押impulse推动, 刺激, 冲动, 推动力, 脉冲impurity杂质, 混杂物, 不洁, 不纯inductance 感应系数, 自感应,电感induction coil电感线圈inductive 诱导的, 感应的inflammable易燃的, 易怒的ingot条，块，锭initial 最初的, 词首的, 初始的initialize初始化initials缩写injector. 注射器injure 损害, 伤害inlet 进口, 入口inlet valve入口阀inner 内部的, 里面的, 内心的,内部inoperative不起作用的；无效的inspection 审查，检查instance 例图；事[实，范]例，样品,实例, 建议, 要求, 情况, 场合instantaneous瞬间的, 即刻的, 即时的,瞬时,立即insufficient不充足的,不适合的，不能胜任的insulation绝热；绝缘；隔离,绝缘体；绝缘材料intensive强烈的, 精深的, . 加强器interchange 互换，交换；交换机interlock连锁装置, 连锁internal callipers内卡钳internal-combustion engine内燃机inertia switch惯性开关interval 间隔，时间间隔，区间intervene干涉, 干预, 插入, 介入inverter反用换流器, 变极器, 反相器；"非"门irregularity 不规则, 无规律不规则性，不正则性irritation激怒；被激怒疼痛处isolating 孤立的,绝缘的isolation 隔绝, 孤立, 隔离, 绝缘, 离析isometric projection等边体isosceles triangle等边三角形Jjack 插孔，插口，插座；插头，接头；千斤顶jet 喷嘴；射流jib crane挺杆臂,转臂起重机jig 钻模；夹具；定位；模具jointing compound复合填料joist托梁 ,搁栅jubilee clipjumper 跨接线，跨接，跨[短]接片，跳接器，∏型短路线Kkeyhole sawkey-operate键盘操作keyway 键槽king dick spannerking pin大头钉kit成套工具, 用具包, 工具箱, 成套用具knob 按钮；调节器knuckle joint万向接头knurled nut凸螺母knurling多瘤的, 多节的Llabel 标签, 签条, 商标, 标志labyrinth迷路, 迷宫, 难解的事物ladder. 梯子, 阶梯ladle杓子, 长柄杓lager贮藏啤酒lagging绝缘层材料laminate 层压(制品)，迭片，迭层板，绝缘板; 碾压lamp holder 灯座lapjoint搭接lap 盖板；搭接，重迭；研磨，抛光lapping compound研磨，抛光化合物large power drill大型钻latch 锁存器；门闩线路；凸轮；闩锁lathe 车床lathe tool车床工具layout 规划, 设计, 编排, 版面, 配线, 企划, 设计图案,布局图, 版面设计leaf spring叠簧leaflet 小叶, 传单leak漏洞, 漏出, 漏出物, 泄漏, 泄漏leakage 漏, 泄漏, 渗漏left-hand thread左旋螺纹lengthwise纵长的，纵向长的level水平, 水平面, 水准, 标准, 级别leverage杠杆作用liberal自由，丰富，充足lid. 盖子lifting提升light光, 日光, 发光体, 灯轻的, 发光的light metal spirit level光金属水平仪lighting conductor光导体limit gaugelining内衬，衬里link链环, 连结物, 火把, 链接, 连结, 联合lintel楣, 过梁lip. 嘴唇, 唇缘lithium saponify锂基脂litre 升local地方的, 当地的, 局部的, 乡土的,当地居民, 本地新闻, 慢车, 局部locate定位，位置location单元；位置，定位lock 加锁，锁(紧，定)，封闭；自动跟踪locking nut自锁螺母locknut防松螺母，对开螺母locomotive 机车, 火车头log(运行)记录,(系统)日志logging saw伐木锯loom. 织布机, 织机, 隐现, 迫近lorry卡车, 铁路货车lost-head nail断头钉loudspeaker 扩音器, 喇叭lubricant润滑剂lubricate 润滑lug 接线柱；柄，把手；突起Mmachine tools 工作母机magnet 磁体, 磁铁magnetic 磁的, 有磁性的, 有吸引力的magnifier 放大器magnifying glass放大镜main主要部分, 体力, 力量, 大陆, 要点, 干线main spar主梁mallet木槌 ,球棍mandrel 半导体阴极金属心；心轴manhole人孔, 检修孔manner礼貌, 风格, 方式, 样式, 习惯manometer 流体压力计manometric. 压力计的, 用压力计测量的manual 手册，指南,人[手]工，手控，手动marine engine海用引擎masonry 石工术, 石匠职业masonry drill石钻masonry nail 水泥钉master征服,控制,精通master cylinder主液压缸mat 字模，垫块material 物质，材料；资料measureing scale测量刻度measuring 测量measuring tape卷尺mechanical机械的, 机械制的, 机械似的mechanical drawing机械图mechanism 机制；机械学，结构方式；机械装置；技巧；机械论medium媒体；介质；平均值；手段，方法；中(等)；粗略，一般[M]membrane 薄膜；隔板；表层memory记忆, 记忆力, 回忆, 存储(器), 存储器存储器,内存mention 提及, 说起mercury barometer 汞，水银气压计meshing接合；相合；啮合message 消息报文，电文；信息micrometer screw gauge螺旋测位器microprocessing unit 微处理器microscope显微镜microswitch 微动开关middle中间，中型；mill 碾磨, 磨细milling轧齿边milling machine 铣床mineral. 矿物, 矿石minimise 成极小,求最小值minor次要，局部，小minus 减(号)；负missing 故障，损失，遗漏mitre block 斜接，斜面接合块mitre joint 斜接mitring machinemix 混合mixture混合, 混合物, 混合剂Monitoring监控mode方式, 模式, 样式, 时尚modem 调制解调器modification修改，改造，改变 ,变型，变体module 模数, 模块, 登月舱, 指令舱modulus模量，系数，模数moisture 湿气，湿度，潮湿molding塑造；铸型；造型塑造物；铸造物mole wrenchmomentary刹那间的；顷刻的；短暂的mortar 臼, 研钵, 灰泥mortise. 榫眼mortise chisel榫.Motor start马达启动moulding sand沙模multimeter 万用表，多用途计量器multi-meter万用表multiplication乘法, 增加,(动, 植的)繁殖, 增殖multiplier 增加者, 繁殖者,乘数, 增效器, 乘法器multiply 繁殖, 乘, 增加Nnacelle发动机舱，机舱nail指甲, 钉, 钉子needle file 针锉needle valve 针形阀, 针状活门negative 否定, 负数,阴性的；负极的network. 网络, 网状物, 广播网neutralization中立化, 中立状态, [化]中和noise噪声 ,噪音non-shrinking非收缩性normal正常，普通，标准nose cone. 火箭或飞弹之鼻锥体, 头锥体nozzle管口, 喷嘴nut 坚果, 螺母, 螺帽, 难解的问题nut tap自攻螺母nylon 尼龙Oobstruct 阻隔, 阻塞, 遮断(道路、通道等), 阻碍物, 障碍物obtuse angle 钝角obtuse-angled triangle钝角三角形occur 发生, 出现off-shore oil rig海上平台oil ringoil switch油开关oil well 油井oilstone油石oldham coupling欧氏联轴节on-site在场open ring wrench开口扳手open-hearth furnace平炉optimum最佳，最优orifice 孔, 口oscillation摆动, 振动outlet 输出；出口；引出线，电源插座output 产量, 输出, 输出量out yawing外偏航oval nail椭圆钉over speed过速overaging超龄的；老朽的；旧式的over current protection过电流保护overhead-valve engine 顶阀发动机,预置气门发动机overheat加热过度使发展过快，使过热overlap重叠，覆盖overload 超载，过载，过负荷overpressure过压overproduction生产过剩overspeed 超速over voltage过电压oxidation氧化[作用]；氧化层oxyacetylene welding氧乙炔焊风电词汇中英文对照表-IIsaddle. 鞍, 鞍状物safety 安全, 保险, 安全设备, 保险装置sample. 标本, 样品, 例子sand blasting沙暴sander 沙, 沙子, [pl. ] 沙滩, 沙地sandingsandpaper砂纸sandwich夹层，层状[夹心]结构satisfactory符合要求的；合适的saturate. 使饱和, 浸透, 使充满saw 锯sawing machinescaffolding 脚手架scale 刻度，标度；比例尺，标尺；尺度，规模；【动】定标；换算；【WIN,NT】数值，缩放(比例scalene trangle不等边的（三角形）scarringscraper刮器，擦具；鞋刮子；刮刀，刮漆刀scratch 划痕，刻痕；【动】擦除；screen 屏(幕,面),荧光屏；筛选；屏蔽；网screw螺丝钉, 螺旋, 螺杆, 螺孔, 螺旋桨, screw callipersscrew clampscrew driverscrew extractor拉马screw jack 螺旋千斤顶screw pitch gaugescrew tap 螺丝攻screw thread. 螺纹screwdriver 螺丝刀,起子scriber划线器, 描绘标记的用具scribing block划线笔sealing密封seam welding接合焊seat座, 座位, 所在地, 场所, 席位secger plierrsecure安全，可靠，保密securedsecurity 安全(性)，保密(性)，安全措施segregation分离，分凝法self-starter自动点火装置；自动启动器self-tapping screw自攻螺丝sensitivity 敏感, 灵敏(度), 灵敏性sensor 传感器，检测器；读出器，感测器；敏感元件sentsequence 顺序，时序；数列；定序，排序，序列series connectionservice 服务，服务程序；业务；维修，维护set screwset squaresetting设置[定]值；设置settle稳定，固定；调整，调度shackle 手铐, 脚镣, 桎梏, 束缚物shaft 轴, 杆状物shank 胫, 腿骨shaping machineshaping toolsharpness锐利shears 剪, 修剪, 剪切shicknessshield屏蔽，罩；防护，庇护shim 垫片；填隙片shimming 摇动,震颤,晃动shock 冲击；震动shock absorber 减震器，震动吸收器short circuit. 短路shovel 铲, 铁铲shrink缩小，收缩shutdown 停止系统运行，停工[机]，关机shutter 遮挡板，光闸，光阀；快门shuttle 梭；航天飞机，宇宙飞船，空间渡船；往返空间sidelight侧面射进来的光线, 侧灯,舷灯, 拾零, 杂闻, 间接说明side-valve enginesight glasssimultaneous同时的, 同时发生的sine wave正弦波single phase单相singnalsink 散热器，接收器，转接器；吸收(电流等)；沟(半导体耗尽层的)；汇点，收点；宿，汇集sintering烧结siphon 虹吸管site-mixedskew wind 歪斜，偏斜，扭斜[曲，动]；相位偏移；变形，时滞(同一脉冲通过不同电路的时差)；不齐，不齐量，偏离；【修】歪，斜，扭skin-halveskip 跳跃(进位)；跳行[越，过]；空指令slag. 矿渣, 炉渣, 火山岩渣sledge hammer大锤, 有压服力的东西sleeve 套筒，套管slide 滑动触头；【动】使滑动slide caliperrslide rule计算尺slide valve滑阀sliding滑动，活动；可调整slight 轻微的, 微小的slipping clutchslope 斜坡, 斜面, 倾斜slot 插槽，存储槽，(页)槽；槽口；开缝，存取窗口；裂缝[口]，切口，沟；时间段，时间片slow-running screwsmelting熔炼smooth平稳，平滑snips 剪断socket 插座[槽，孔，口]；管座；套接字(报文包的)；【SunOS】网络界面[接口]；【网】报路[SK]socket spanner套筒扳手soft cut in软切入software软件，软设备soldering 焊料，焊锡；焊接，结合soldering iron 烙铁solenoid螺线管solenoid valve电磁阀solitary单独，唯一solvent溶媒, 溶剂, 解决方法spacer. 取间隔的装置, 逆电流器，衬垫，衬套，衬片spade 铲, 铁锹spanner扳手；活络扳手；扳子sparking plug 火花塞spigot 插口；插头，塞子；(水)龙头spindle 主轴，心轴spinner 微调控制项spiral gear螺旋齿spirit level 水平仪spirit varnishsplash. 溅, 飞溅, 斑点spline方栓, 齿条, 止转楔, 花键splined shaftsplint夹板，托板split bearing分离轴承split pinspokeshave辐刀spot 斑点，点；地点；点焊spot welding点焊sprayer 喷出水沫者, 喷雾, 喷雾器sprig图钉spring 弹簧；【动】弹出spring balance弹簧秤spring washer弹垫spring-bow compasssprocket 链轮齿spur gear正齿轮spur wheel gear正齿轮square 平方；方块；【修】矩形[SQ]，正方形的, 四方的,直角的, 正直的, 公平的, 结清的, 平方的, 彻底的square nut 四方螺母, 螺帽square thread矩形螺纹square-head bolt方头螺栓stabilizer稳定器；平衡器；安定剂stable稳定，稳态stage 级；阶段，程度；【动】登台，升级stain 着色，染色；着色剂；污点stainless 纯洁的, 无瑕疵的, 不锈的stall失速，使失速standard标准(型)，规范，准则；【印】常身；正常体standing 直立的, 停滞的, 固定的, 常备的, 标准的, 常设的standstill静止状态；停顿star drillstart up 发动, 开动starter motor马达启动startup 启动steam engine 蒸汽机steam roller蒸汽压路机, 高压手段steam turbine 蒸汽轮机steel sheet scissorsteel wool钢丝线steering box舵盘steering gear方向齿steering wheel舵轮，方向盘step-down(up) transformer降压器stiffen 变粘, 变硬, 变猛烈stillson wrenchstipulate 规定, 保证stock 库存, 股票, 股份, 托盘, 祖先, 血统, 原料stoker 司炉, 烧炉工人, 加煤机stopcock管闩, 活塞, 活栓, 旋塞阀stoppage 中断, 填塞store 存储，存储器straight edge直刃strange陌生的, 生疏的, 前所未知的, 奇怪的, 奇异的, 不惯的strap 短接，跨接strap wrench绑扎带streak 条纹，拖尾strike 打, 打击, 罢工, 抓, 敲, 搏动, 打动, 穿透strip 条，带，(跨接)片；剥离，脱去，去除striplightstructure结构，构造，构件；structure结构，构造，构件；【C】(数据类型)结构，结构体[STRUC]stub axlestudstuffing box填充体sturdy 强健的, 坚定的, 毫不含糊的substantial 坚固的, 实质的, 真实的, 充实的substation变电所，分站，支局subsynchronous 次[再]同步suck 吸, 吮, 吸取suction. 吸入, 吸力, 抽气, 抽气机, 抽水泵, 吸引summation 求和，总和，加法sump润滑油槽；油盘；机油箱superheated 过热supervise监控，监督support 支援，支持(程序，软件)；配套[SU]surface 表面，曲面；【修】表面，外部surplus 过剩，余量surrounding 围绕物, 环境suspension 吊, 悬浮, 悬浮液, 暂停, 中止, 悬而未决, 延迟，挂起；暂停，中止suspension systemsweating. 出汗的, 吃力的swept planeswitch 开关，转[交，切]换，翻转；接线器switch box开关柜switch off 切断switch over 转变symmetry对称，对称性synchronous同时的, [物]同步的synthetic合成的, 人造的, 综合的Ttachometer转速计，转速器tacktailstocktamperproof 防止窜改，可防止乱摆弄tangent 正切；切线，接触的, 切线的, 相切的, 离题的tank 储能电路；槽，箱，容器；油箱tap 分接头，抽头，三通头,, 活栓, 水龙头tap extractortap wrenchtap-drilltapdrill extensiontape 磁带，纸带；【修】带状tape decktape recordertaper 圆锥；递减；【修】分等级tappet 梃杆, 凸子tarmac 停机坪telephoto lens 远摄镜头,长焦镜头telescopic shaft伸缩轴television 电视, 电视机temperature 温度tempering 回火template样板，金属模片temporary暂时的, 临时的, 临时性tenon凸榫，雄榫，榫舌tenon sawtensile可拉长的, 可伸长的, [物]张力的, 拉力的tension压力, 张力, 牵力, 电压terminal point端子terminate 端接；终止test nipple测试嘴test piecetesthose for manomentert-head bolt T形头螺栓T-head bolt T型螺栓theodolite经纬仪thermal热的；热量的；热力的thermistor热敏电阻，热控管thermocouple温差电偶，热电偶thermograph温度记录器, 热录像仪thermometer . 温度计, 体温计thermostat自动调温器，恒温器thinner稀释剂，冲淡剂thread线, 细丝, 线索, 思路, 螺纹，线索；线程three way switch三路开关three-jaw chuckthrottle valve节流阀throttles节流阀；节流圈；风门thrust bearing推力轴承thyristor硅控整流器，半导体闸流管tie beamtime switch定时开关timing chain调速链timing gear调速齿tip尖头，技巧，端头，触点；忠告，提示toggle joint双态元件，触发器；(乒乓)开关；轮转，(来回)切换tolerance公差，容差[限，许]，允许误差；容错度tolerate忍受, 容忍tommy bar撬棒,螺丝钻tongs钳子, 夹具tongue and groovetooqh强硬的tool box工具箱tool post工具站toolbox工具箱top dead-centretopmost最顶层，最高，最上面torch手电筒，火把；火炬torque arm力臂torque spanner力矩扳手torque wrench力矩扳手torsion扭(转)；扭力；挠率；转矩torsion bar力矩杆torus 环形圆纹曲面，(圆)环面touch 触力；【动】按，揿，触toward. 向, 对于, 为了Towertower crane塔式吊车track rod磁棒tractor. 拖拉机， (履带式)输[进]纸器trailing (轨)迹；跟踪；【WIN】指针train 串，列，系列；链；列车trammel 拘束, 阻碍物, 束缚物transformer变压器transistor 晶体管transmission 传输，发送，传送TransmissionTransmitter发射器，变送器transport 运输；运输工具transverse横切的，横轴transverse engine水平机trapezium梯形travelling crane移动式吊车tread踩，踏treadle踏板trestle架，架柱triac 三端双向可控硅开关元件triangle三角(形)trigger触发trimming清理焊缝triple三层的，三倍的triple phase三相tripod三角架trowel泥刀, 小铲子try square曲尺, 检验角尺t-square丁字尺tubular管状的，管形的turbojet涡轮喷气飞机turbongeneratorturning 旋转, 转向, 转弯处turnstile 十字转门turntable转车, 转盘turret lathe 六角车床twist . 盘旋；缠绕twisting缠绕two-handed sawtwo-stroke engine二冲程发动机Uu-bolt U形螺栓ultrasonic超声波unbalance不平衡unconditional. 无条件地uncritical不加批判的, 无批判力的, 不严厉的under load switch底载荷开关under voltage低电压underfeed stokerundershot wheelundulate起伏uniform一样的union联合；联合会，团结unit单元，部件，单位(符号)；装置，设备，器件universal coupling万向联轴节,万向连接器universal joint万向接头,万向节universal pliers万能手钳unloading卸,去载unscrew从...旋出螺丝, 旋开, 旋松unsymmetry不匀称untwisting拆开(搓合的绳,线等), 解开update更新；修改；校正；重新编辑。

2023-2024学年江苏省镇江市高三下学期期初适应性练习英语试题

2023-2024学年江苏省镇江市高三下学期期初适应性练习英语试题Contrary to popular belief, winter is actually a good time to travel. Below, you’ll find recommendations for the best places to visit in winter in the USA.Sequoia (美洲杉) National Park, CaliforniaThis park is famous for its giant sequoia trees. And though it’s impressive to walk among 250-foot sequoias, snowshoeing or cross-country skiing through Giant Forest Grove when the towering trees are dusted with snow is pure magic.Accommodation: The centrally located Visalia Marriott is just 40 minutes from the park gate. Charleston, South CarolinaStart your weekend getaway on a historic carriage ride downtown in cold winter. Clip-clop past the city’s churches, see where they stored all the gunpowder back in the 1700s and learn about Charleston’s past.Accommodation: Located in the city's historic heart, the Charleston Place hotel features plush rooms and excellent dining.Keystone, ColoradoSki report website On the Snow rates it the top resort for families, thanks to free parking; ski-in, ski-out lodgings; a kids-ski-free program; and beginner terrain (地形).Accommodation: Keystone Lodge and Spa has cozy mountain-inspired rooms and lofts, a heated outdoor pool and hot tub.Park City, UtahLocated just 40 minutes from Salt Lake City, the largest ski resort in the United States is known for its light, dry snow, sunny skies and variety of terrain.Accommodation: Marriott’s Summit Watch is an affordable option located right in Park City, and it offers accessible rooms.1. What will travelers do in Charleston?A．Walk along giant sequoia trees. B．Ski through snow-covered forests.C．Explore the historic city. D．Swim in a heated outdoor pool.2. Which destination gives kids a chance to ski for free?A．Sequoia National Park. B．Charleston.C．Keystone. D．Park City.3. What do the four destinations have in common?A．They are located 40 minutes from the nearby city.B．They are famous national parks in the USA.C．They offer carriage rides at weekends.D．They offer a range of cold-weather fun.It’s an unusually calm morning for Jim Smith, owner of Ventura Dive Sport, and lifelong seaman. He’s in charge of the Raptor, carrying a boatload of divers and snorkeling(浮潜) enthusiasts over to the Channel Islands anchored just off the Southern Californian coast, in the remote Channel Islands National Park.On this trip, in particular, Smith is hoping to spot giant black sea bass, a huge underwater creature that grows over seven feet long and can weigh more than 700 pounds. Unsurprisingly, it’s a fish that sits atop the food chain, and the species is an important part of the marine (海洋的) ecosystem.Up until the 1970s, black sea bass were a common sighting in Southern California, but due to overfishing their population dramatically declined. As a result, fishing for giant black sea bass of any kind was banned in California in 1982. In the Channel Island region, thanks to the protected waters of the national park, there is a promising sign-a recent survey found around 50 individuals around the Catalina Island alone.Marine biolo gists’ photos-and indeed anyone else’s-now have a permanent home, on a newly-created database named Spotting Giant Sea Bass. The website, launched and run by the Aquarium of the Pacific in July, is a joint community effort to find out more about these mysterious creatures. Scientists hope to be able to answer how the population is changing over time, how far giant sea bass move, where they spawn (产卵), and how they grow in marine protected areas. With more than 1 million dives recorded annually across the Go lden State’s coastline, researchers hope a joint effort to document this species will aid with its recovery.“One of the main things people want to see when they come out with us during September and October is giant sea bass,” Smith says. “If you’re luck y enough to be on a dive and one swims past you. . . it really is the most incredible experience. ”4. Who is Jim Smith?A．A marine biologist.B．A dive boat captain.C．A founder of a website.D．A guard of a national park.5. What can we infer about black sea bass in the Channel Island region now?A．They are experiencing population growth.B．They are being overfished.C．They are living in terrible conditions.D．They are disappearing due to pollution.6. Which of the following is considered as “a permanent home” in paragraph 4?A．Southern California.B．Spotting Giant Sea Bass.C．Marine protected areas.D．The Aquarium of the Pacific.7. What will be helpful for the recovery of black sea bass according to the researchers?A．Swimming with them in the sea.B．Prohibiting deep-sea diving.C．Working together to record information.D．Discovering more islands.Emotions are like our best friend. They have always been a part of our lives and have been influencing our personalities from the very beginning. However, this begs the question-where do emotions come from?Evolutionary (进化论的) psychologists believe that emotions are adaptations that have evolved in response to the challenges faced by our ancestors. They believe that emotions are innate (先天的), meaning that we are born with them wired into our brains.Some psychologists restrict their claims to a small set of “basic” emotions, which are called the Big Six-happiness, sadness, fear, surprise, anger and disgust.Critics of evolutionary psychology argue that emotions are socially constructed. They reject the evolutionary theory of emotions being involuntary; instead, they believe that emotions are voluntary choices we trick ourselves into treating as involuntary.Defendants of this view believe that our culture influences how we should feel and what we should do in a given situation. When we feel an emotion and act on it, we engage in a behavior that is prescribed by our culture.People argue that our presumption that emotions are involuntary, such as anger, may just be a convenient illusion (幻觉). To be angry, we need to understand something as offensive (冒犯的), which is likely based on culturally informed moral judgments. In that case, how can anger be an animal reflex (本能反应)？Moreover, anger is not seen in all cultures. In Inuit culture, people rarely show any signs of anger, probably since threatening responses would be too risky in a small culture surviving in harsh conditions. The Malay language of Malaysia doesn’t even have a word meaning “anger”!The fact that culture can affect the incidence and intensity of our emotions makes them look less like biological truths and more like the product of social constructs.From my perspective, evolutionary psychologists underestimate the contributions of culture and learning, whereas social constructionists over-emphasize the same. Basically, we need an explanation that can steer between both these extremes.The next time you feel a complex emotion bubbling up (冒出), the key is to determine the underlying basic emotions so you can take action that is the most helpful in keeping you balanced and emotionally under control!8. What do evolutionary psychologists believe?A．We are born with emotions.B．Personalities influence emotions.C．Emotions are learned.D．Humans have six different emotions.9. What does the underlined word “prescribed” in paragraph 5 mean?A．Copied.B．Remembered.C．Translated.D．Required.10. What do the two examples in paragraph 7 mainly explain?A．Emotions play a major role in survival.B．People in poor circumstances have emotions.C．People solve problems with the help of emotions.D．Emotions are socially constructed.11. What is essential when facing the occurrence of a complex emotion?A．Finding out the real core emotions.B．Taking action to ignore basic emotions.C．Striking a balance between life and work.D．Making efforts to build confidence.Active noise control technology is used by noise-canceling headphones to minimize or completely block out outside noise. However, despite the many advancements in technology, people still don't have much control over which sounds their headphones block out and which they let pass.Now, deep learning algorithms (算法) have been developed by a group of academics at the University of Washington that enable users to select which noises to filter (过滤) through their headphones in real-time. The system has been named “semantic hearing” by its creators.The Al-powered headphones remove all background noise by streaming recorded audio (音频) to a smartphone that is linked to the devices. Through this process, the headphone users can choose to strengthen or cancel out 20 types of sounds, using voice commands or a smartphone app. The headphones will then only let through the sounds that have been chosen by the wearer.“The challenge is that the sounds headphone wearers hear need to syne (同步) with their visual senses. This means the neural (神经的) algorithms must process sounds in under a hundredth of a second.” said senior author Shyam Gollakota, a UW professor.Due to this time constraint, the semantic hearing system chooses a process that relies on noises communicated on a device like a linked smartphone. Furthermore, in order for humans to continue to effectively experience sounds in their environment, the system needs to maintain these delays because sounds coming from different directions enter people's ears at different times.Trials were undertaken by the researchers in a variety of settings. The semantic hearing system was able to isolate target sounds, while at the same time removing background noise. In terms of the system's audio output for the desired sounds. 22 participants gave it an average rating higher than they assigned to the original noise recordings.There were, however, a few disadvantages: the Al-powered system occasionally had trouble recognizing sounds that were too similar. The researchers said that the system could produce better results if its machine learning models were trained on more real world data.12. What can deep learning algorithms do?A．Improve users listening ability.B．Help users remove unwanted noise.C．Stop people from entering noisy areas.D．Create communication between users.13. What should the neural algorithms do according to Shyam Gollakota?A．Select headphone users.B．Process data without noticeable delay.C．Follow the way people speak.D．Improve the quality of smartphones.14. What did the researchers find about the system in the trials?A．It has improvement in sound quality.B．It helps them recognize participants' voices.C．It has more disadvantages than advantages.D．It's suitable to strengthen background noise.15. Which is the most suitable title for the text?A．The semantic hearing system still has some drawbacksB．The semantic hearing system can recognize human speechC．Al noise-canceling headphones let you choose what you hearD．AI noise-canceling headphones now have a commercial versionWinter can cause damage to your skin, and it can feel like there’s no escape. 16 . Happily, there are many ways to deal with dry skin and keep yourself comfortable.• Use a humidifier (加湿器) to increase humidity.In the cooler winter months, a humidifier in your home or office will restore moisture to the air, helping to keep your skin hydrated (含水的).Run a humidifier in your entire home or in rooms you spend the most time in, and aim to keep indoor humidity levels between 30 and 50 percent. 17 If you’re unsure of your home’s humidity levels, you can buy a humidity meter.• Keep thermos tat (恒温器) temperatures cool and comfortable.If you’re looking to escape dry, cold outdoor air, you are likely to turn on the heat as soon as you get home. 18 Try a cool yet comfortable setting to prevent your skin from drying further-the American Osteopathic College of Dermatology recommends 68 to 75 degrees F.• 19Long, steamy showers may sound like a great idea when it’s cold, but very hot water can dry out the skin. A 5-to 10-minute warm shower is less likely to worsen dry skin than a hot one.You should also avoid using excessively hot water to wash your hands. Dry skin from exposure to hot water or cool winter air can cause an eczema (湿疹). 20If you still experience dryness, discomfort, and redness after trying these healthy skin tips, experts suggest using an over-the-counter I percent hydrocortisone cream or talking with your doctor.During the final term of my theater and performance degree at the University of Leeds, we planned to _________ some interactive workshops with elderly residents to try to _________ memory and social engagement.I remember being _________, aware that we were working with old people who were almost nonverbal (不能说话的).I had decided to play music at the end of the session. We went with the song My Way _________ those elderly residents would have been listening to the hit song in their late 20s. Once I pressed play, nearly everyone in the room stood up and _________ what seemed like every word. I was so deeply _________. Many of them were communicating much better. It looked and felt like_________.Off I went to drama school, but I thought about that _________ almost daily. So when we were given the opportunity to write a script (剧本) for a _________ festival, I created a love story about __________ and dementia (痴呆), spanning 50 years of a coupl e’s life.And now, 10 years later. the show I __________ is running again in London thanks to the Music for Dementia campaign.I now know that music-based interventions (治疗) __________ the need for antipsychotic medication (抗精神病药物) in more than 60 percen t of people __________ dementia. I don’t know what my My Way would be, but I certainly think we should all try to find our __________ and do our best to stay connected to the people we __________ it with.21.A．hold B．stop C．delay D．suspend22.A．remove B．identify C．inspire D．assess23.A．thrilled B．nervous C．ashamed D．delighted24.A．until B．unless C．if D．because25.A．sang B．said C．heard D．wrote26.A．scared B．moved C．amused D．annoyed27.A．art B．magic C．hope D．mercy28.A．problem B．goal C．policy D．experience29.A．theater B．science C．flower D．sports30.A．water B．fruit C．music D．food31.A．performed B．watched C．recorded D．made32.A．repeat B．protect C．reduce D．ignore33.A．living with B．hearing of C．escaping from D．focusing on34.A．show B．time C．speech D．song35.A．take B．share C．discuss D．learn阅读下面短文，在空白处填入1个适当的单词或括号内单词的正确形式。

鼻声反射和鼻阻力对结构性鼻通气障碍患者的评估价值

• 130 .丨叫¥H：鼻咽喉头颈外科朱忐202丨年5月第45卷第3期Int J Otolaryngol Head Neck Surg, M a y2021, Vol.45, No.3•鼻科学：论著•鼻声反射和鼻阻力对结构性鼻通气障碍患者的评估价值张红蕾王立宏王枫刘鸿毅邓洁龚学晨濮或郭睿空军特色医学中心耳鼻咽喉头颈外科，北京100142通信作者：郭睿，Email:alali626@【摘要】目的鼻声反射和鼻阻力对结构性鼻通气障碍患者的评估价值及与鼻腔结构指标的相关性研究方法选择2018年3月〜2020年1月空军特色医学中心耳鼻咽喉头颈外科收治的结构性鼻通气障碍患者131例作为对象，采用视觉模拟量表评分对患者的鼻堵情况进行评分，根据结果将其分为轻度鼻堵组36例、中度鼻堵组57例、重度鼻堵组38例，另选同期体检者42名作为对照组。

各组均进行鼻声反射测M和鼻阻力测量。

对各组间鼻声反射和鼻阻力测量情况进行比较，并采用Pearson相关性分析对鼻呼气相总阻力、鼻吸气相总阻力与鼻腔结构测M指标的相关性进行分析结果重度鼻堵组鼻声反射指标与其他各组差异更为明显(/><0.05);鼻腔总阻力在对照组与轻度鼻堵组和中度鼻堵组间无统计学差异，与重度鼻堵组间有统计学差异；轻度鼻堵组、中度鼻堵组、重度鼻堵组的鼻腔阻力差异比均高于对照组(P<〇.〇5)，其中重度鼻堵组鼻腔阻力差异比勺其他三组均有统计学差异（P<〇.〇5):鼻吸气相总阻力、鼻呼气相总阻力勹下鼻甲前缘黏膜至鼻中隔之间距离、双侧下鼻甲软组织内侧缘之间最小距离（和双侧下鼻甲骨之间最小距离）呈负相关，数据差异具有统计学意义(P<0.05)结论鼻声反射和鼻阻力检测对结构性鼻通气障碍患者的鼻通气功能貝•有一定的评估价值，鼻腔扩容手术可以显箸改善结构性鼻通气障碍患者的鼻通气功能【关键词】鼻测量，声学；鼻腔测压；鼻阻力；结构性鼻通气障碍；评估；相关性基金项目：军事飞行人员疾病特许医学鉴定指南研究（A K j15J003)DOI: 10.3760/cma.j.issn.l673-4106.2021.03.002Evaluation of nasal acoustic reflex and nasal resistance in patients with structural nasalventilation disordersZhang Honglei, Wang Lihong, Wang Feng, Liu Hongyi, DengJie, Gong Xuechen, Pu Yu, Guo RuiDepartment o f Otorhinolaryngology' Head and Neck Surgery^ the Air Force Medical Center, PLA,Bejing 100142, ChinaCorresponding author: Guo Rui, Email:****************【Abstract】Objective To study the evaluation value of nasal acoustic reflex and nasalresistance in patients with structural nasal ventilation disorders and the correlation between them andnasal structural indexes. Methods From March 2018 to January 2020, 131 patients with structuralnasal obstruction who were admitted to our hospital were selected as the subjects, and the visualanalogue score was used to score the situation of nasal obstruction. According to the results, theywere divided into 36 cases of mild nasal obstruction group, 57 cases of moderate nasal obstructiongroup, 38 cases of severe nasal obstruction group, and 42 cases of physical examination at the sametime were selected as the control group. Nasal acoustic reflex and nasal resistance were measuredin each group. The results of nasal acoustic reflex and nasal resistance were compared among thegroups, and Pearson correlation analysis method was used to analyze the correlation between thetotal expiratory phase resistance, the total inspiratory phase resistance and the measurement indexof nasal structure. Results There was significant difference in the measurement of nasal acousticreflex among the groups(P<0.05); there was no significant difference in the total nasal resistancebetween the control group and the mild and the moderate nasal obstruction groups, and there wassignificant difference between the severe nasal obstruction groups; the difference of right-left nasalresistance ratio between the mild, the moderate and the heavy nasal obstruction groups was higherthan that of the control group(P<0.05), and the severe nasal obstruction group was higher than thatof the control group(尸<0.05); There was a negative correlation between the total inspiratory phaseresistance, the total expiratory phase resistance and the distance of the inferior turbinate front tonasal septum(DTNS), The minimal distance between the inferior turbinate soft tissue(MDTT) andthe minimal distance between the inferior turbinate bone(MDTB). The difference was statisticallysignificant(戶<0.05). Conclusions Nasal acoustic reflex and nasal resistance test can be used toevaluate the nasal ventilation function of patients with structural nasal ventilation disorders. Nasaldilatation surgery can significantly improve the nasal ventilation function of patients with structuralnasal ventilation disorders.【Key words】Rhinometry, Acoustic; Rhinomanometry; nasal resistance; structural nasalventilation disorders; evaluation; correlationFund program: Study on the Medical Identification Guide for Military Pilots(AKJ15J003)DOI: 10.3760/cma.j.issn. 1673-4106.2021.03.002国际浑鼻咽喉头颈外科杂忐202丨年5月第45卷第3期____________Int J Otolaryngol Head Nec k Surg, M a y2021, Vol.45, No.3 . 131 .结构性鼻通气障碍是鼻腔解创结构异常导致的通气障碍，以鼻塞为主要临床表现，鼻腔扩容手术可有效增加鼻腔通气量，降低鼻腔阻力^21。

水库白蚁等害堤动物防治方案

水库白蚁等害堤动物防治方案英文版Reservoir Termite and Other Embankment-damaging Animal Control ProgramIntroductionReservoirs play a vital role in water supply, flood control, and irrigation. However, the integrity ofreservoir embankments can be compromised by various animals, including termites and other burrowing animals. These animals can create tunnels and galleries within the embankment, weakening its structural integrity andincreasing the risk of seepage or failure.ScopeThis program aims to prevent and control theinfestation of termites and other embankment-damaging animals in reservoirs. It includes techniques for monitoring, detection, and eradication of these pests.Monitoring and DetectionRegular inspections of embankments for signs of infestation, such as mud tubes, holes, or activity around vegetation.Use of non-destructive testing methods to identify internal tunnels or galleries.Deployment of acoustic sensors to detect animalactivity within the embankment.EradicationChemical treatment using insecticides specifically formulated for termite control.Physical removal of animals through trapping or excavation.Biological control using predators or parasites.PreventionMaintaining proper vegetation management around embankments to reduce attractants for animals.Sealing cracks and crevices that may provide entry points for pests.Installing physical barriers, such as wire mesh or concrete collars, to prevent burrowing.ImplementationThe program will be implemented through a multi-agency approach, involving reservoir operators, pest control companies, and environmental regulators. Regular monitoring and evaluation will be conducted to assess theeffectiveness of the program and make necessary adjustments.ConclusionBy implementing this comprehensive control program, reservoirs can effectively protect embankments from the damaging effects of termites and other pests, ensuringtheir structural integrity and safety.中文翻译水库白蚁等害堤动物防治方案引言水库在供水、防洪和灌溉中发挥着至关重要的作用。

Vibration and Acoustics

Vibration and AcousticsVibration and acoustics are two interconnected fields of study that have a significant impact on our daily lives. From the hum of a car engine to the soothing sound of waves crashing on the shore, acoustics plays a vital role in our perception of the world around us. Similarly, vibrations can be felt in the rumble of a passing train or the gentle buzz of a smartphone. However, these phenomena can also have negative effects, such as the discomfort caused by a noisy environment or the structural damage resulting from excessive vibrations. In this response, we will explore the various aspects of vibration and acoustics,including their effects on human health, their applications in different industries, and the technologies used to measure and control them. One of the most significant aspects of vibration and acoustics is their impact on human health and well-being. Excessive exposure to noise, whether from traffic, industrial machinery, or construction activities, can lead to hearing loss, sleep disturbances, and increased stress levels. Similarly, vibrations from heavy machinery or transportation vehicles can cause discomfort and even musculoskeletal disorders in individuals who are regularly exposed to them. As a result, there is a growing emphasis on the need to control and mitigate these effects, particularly in urban environments where noise pollution is a significant concern. Researchers and engineers are continuously developing new technologies and materials to reduce noise and vibration levels, with the aim of creating healthier and more comfortable living and working spaces for people. In addition to their impact on human health, vibration and acoustics also play a crucial role in various industries and scientific fields. For example, in the automotive industry, engineers strive to minimize the noise and vibrations produced by vehicles to enhance the comfort of passengers and reduce the impact on the environment. In the field of civil engineering, the study of acoustics and vibrations is essential for designing buildings and infrastructure that can withstand environmental forces and provide a safe and pleasant environment for occupants. Moreover, in the field of music and entertainment, acoustics is a fundamental consideration in the design of concert halls, recording studios, and sound systems, as it directly affects the quality and experience of the music. Technological advancements have played avital role in the study and control of vibration and acoustics. For instance, the development of advanced sensors and measurement devices has enabled researchers to accurately quantify and analyze noise and vibration levels in different environments. This information is crucial for identifying the sources of noise and vibrations and developing effective strategies to mitigate their effects. Furthermore, the use of computer simulations and modeling techniques has allowed engineers to predict and optimize the acoustic and vibrational performance of various systems and structures, leading to more efficient and sustainable designs. Additionally, the use of active control systems, such as noise-canceling headphones and vibration isolation mounts, has provided individuals with practical solutions to reduce the impact of noise and vibrations in their immediate surroundings. In conclusion, vibration and acoustics are complex and interconnected fields that have a profound impact on our daily lives. From their effects on human health and well-being to their applications in various industries and the technologies used to measure and control them, these phenomena continue to be the focus of extensive research and development efforts. As our understanding of vibration and acoustics grows, so does our ability to create healthier, more comfortable, and more sustainable environments for people to live and work in. It is essential for researchers, engineers, and policymakers to continuecollaborating and innovating in these areas to address the challenges posed by noise and vibrations and to harness their potential for positive impact.。

基于速度反馈控制的自激振动特性研究

基于速度反馈控制的自激振动特性研究冯伟;宋汉文【摘要】工程中自激振动常被作为不利因素而加以抑制,然而在振动能量捕获等振动利用研究中,自激振动也有振幅响应大、抗干扰能力强等优点,利用自激振动作为振动驱动将具有极大的优势.以悬臂梁为研究对象,通过模态参数与测点组合条件,导出了基于速度反馈控制下各阶模态的变化模式,得到了产生自激振动的数值判据,并对单模态进入自激振动以后的非线性极限环现象进行了讨论.通过理论建模、数值仿真和控制实验及数据处理,验证了该研究的正确性.%Self-excited vibration is often suppressed as an unfavorable factor in many engineeringfields.However,some special characteristics of self-exited vibration,such as,large amplitude response and strong anti-disturbances capability make it be an ideal driver for vibration utilization study,specifically,vibration energy harvesting.Herer,varying patterns of each mode and numerical criteria of self-excited vibration under control of velocity feedback were derived in studying cantilever beams with constraints of modal parameters and test points.One phenomenon,i.e.,the nonlinear limit-cycle produced by a single mode self-exited vibration was discussed as well.The correctness of this study was verified with theoretical modeling,numerical simulation,control tests and data processing.【期刊名称】《振动与冲击》【年(卷),期】2017(036)007【总页数】6页(P86-91)【关键词】自激振动;反馈控制;模态分析;极限环【作者】冯伟;宋汉文【作者单位】同济大学航空航天与力学学院,上海200092;同济大学航空航天与力学学院,上海200092【正文语种】中文【中图分类】TB53;O323;TB123经典结构动力学主动控制领域的研究始于20世纪50年代，取得了丰富的研究成果[1]，广泛应用在航空航天、高速铁路、土木工程[2]等领域。

nvh效率优化算法

nvh效率优化算法NVH（Noise、Vibration、Harshness）效率优化算法主要针对汽车工程中的噪音、振动和粗糙度问题进行优化。

为了提高NVH性能，研究人员提出了许多算法和方法，以下是一些常见的NVH效率优化算法：1. 主动噪声控制（Active Noise Control，ANC）：主动噪声控制是通过计算目标噪声源的逆傅里叶变换，生成一个与目标噪声相位相反的声波，从而实现噪声消除。

主动噪声控制方法包括前馈控制、反馈控制和自适应控制等。

2. 主动振动控制（Active Vibration Control，AVC）：主动振动控制是通过实时测量系统的振动响应，计算出振动控制信号，然后通过执行器对振动进行抑制。

主动振动控制方法包括频域控制、时域控制和模型预测控制等。

3. 结构优化算法（Structural Optimization，SO）：结构优化算法是通过调整结构参数，使系统的振动特性得到改善。

常见的结构优化方法有有限元优化、遗传算法、粒子群优化等。

4. 声学优化算法（Acoustic Optimization，AO）：声学优化算法主要针对汽车内部和外部的声学环境进行优化。

常见的声学优化方法有边界元法、有限元法、统计能量分析法等。

5. 灵敏度分析法（Sensitivity Analysis，SA）：灵敏度分析法是通过计算各设计变量对目标函数的贡献程度，找出对NVH性能影响较大的设计变量，从而指导设计改进。

6. 神经网络优化算法（Neural Network Optimization，NNO）：神经网络优化算法通过训练神经网络模型，实现对NVH性能的预测和优化。

常见的神经网络模型有feedforward 神经网络、recurrent 神经网络等。

7. 模糊逻辑优化算法（Fuzzy Logic Optimization，FLO）：模糊逻辑优化算法是基于模糊规则进行推理，从而实现对NVH性能的优化。