difficult, not hating; blueprints, not rhetoric; words and simple, but full of love, truth, passion, entrepreneurial passion. Take this opportunity, my inspirational quotes Li Dazhao's classic \lise in uplifting blend with the article\h a view on how to do well under the new situation of township and village leaders inspire and help, and also share with you. A good play to create iron shoulders strong arms, to assume the burden be passed; only specific qualities, will it be possible in specific areas to create a world. In my view, village chiefs in the new situation, we must first have five basic quality. One ambition is to pioneer. \handsome.\h-minded can stimulate the flow of momentum to become brave and persistent, become quiet and powerful. Township and village party \hin their respective jurisdictions, political stability and economic and social development issues, decisions and orientation depends to a large extentbecause of your. Everybody in village chiefs and the positions, both the trust of the masses, the Organization's trust, more ability to you, fully affirmed the moral and other qualities. Therefore, we must always maintain the historical mission and social responsibility, and our ideal tree rooted in the hard work of the soil, with indomitable spirit, indomitable courage to open up a new situation of villages and towns. To have a feeling of closeness to the second. \he people and country.\business foundation in the people's blood in the people power people. Advanced decisions of the party cadres to the feelings of the people is an eternal theme. Fan Zhong-yan, called \njoy comfort about others\Banqiao's also wrote a \a Chai lay listening to the rustling of bamboo, the suspect is suffering. Cao County officials, little my, a total turn off. \l official even has so feelings, alone we is to\ng \s of people servant does? we more should always hold with on people of deep feelings, heart Department masses of leading visited tea, care masses of emotions thoughts complained, always insisted put masses of interests put in first, consciously from itself do up, from small do up, from masses most care, and most directly, and most reality of interests problem grabbed, real do love for people by Department, and right for people by with, and Lee for people by conspiracy to. Three with the fame of mind. \hout serenity not go far.\s the sublimation of the soul. As ownship and village, be sure to maintain a normal state of mind, establish a correct viewpoint on power, position and values and Outlook, as fame is light like water, depending ... 50 km, also red and like hundreds of thousands of the KMT military combat, but he went on to collect a variety of newspapers and magazines, and then race against time to pore over. As long as the study of mind, it is not necessary to come to the library, workshops, into the villages, people learned farming techniques, problem-solving methods, participation in
课题论文
课题名称 系 部 专 业 班 级 姓 名 学 号
检测技术在模具中的应用 材 料 工 程 系 材料成型及控制工程（模具方向）
KT933-2 姜天闻
指导教师签名（校内）
2013
年
4 月 29 日
conferences, learned superiors policies; reports, you can learn to deal with problems, art, just wanted to learn, to learn at any time. To continuously expand the scope of the study. The complexity and comprehensiveness of our work, decided to not only do we want to be \different areas of knowledge. Mastery of knowledge not only to have knowledge to rational analysis. This on requirements we, not only to learning national of route, and approach, and policy, also to learning national of legal, and regulations; not only to with political theory armed mind, also to with economic theory guide work; not only to read history, also to read history; not only to absorption SM of mirror, also to gets is of road; not only to from local learn, also to to outside learn; not only to to books learn, also to field study learn. Therefore, I would encourage you, and more to the outside world when I have time to take a look at, take a stroll, outside developments, learn other people's development approach, and then come back to guide our work. Second, we must think. \ng without thought to overshadow, thinking without learning is perilous.\of advancing with the times, forge ahead, often reflect themselves in adapting to the new situation on whether there are delays, have anything to fear in the reform and innovation, whether in terms of accelerating the development of a relaxation, keep promising State of mind. In order to do investigations, investigations is the road to heaven, God disposes of the base. To wants to real heard truth, and justice to truth, and get truth, received effectiveness, on must in-depth actual, and outreach, and in-depth masses, worship masses for Division, and masses heart, with masses with discussion everyone care of problem, listening they of calls, understand they of mood, feel they of suffering, summary they of experience, concentrated they of wisdom, especially on masses mosthope, and most urgent, and most worries, and most complained of hot, and difficulties and focus problem, more to active research, caught not put. Dare to innovate, in our work, often remain \d way doesn't work, the new approach would not\on, the reason, the key is that many people know that copying other people's ideas, mechanically, using someone else's old ways. To change this predicament, requires us to break the shackles of traditional concepts to overcome conservative, conformist, good at finding new problems and to accept new things, summarize new experience, new ideas, developing new programmes and Maverick, a new approach to solve problems, speed up development. Especially in implement superior policy spirit of process in the, both implementation, and cannot mechanically, to to extraordinary of courage and develop enterprising of spirit, put flexibility and principle combined up, put superior of spirit and local reality combined up, Yong conspiracy to breakthrough of policy, and exercise innovation of lift, developed out development works of, and grass-roots welcomes ofdifficult, not hating; blueprints, not rhetoric; words and simple, but full of love, truth, passion, entrepreneurial passion. Take this opportunity, my inspirational quotes Li Dazhao's classic \lise in uplifting blend with the article\h a view on how to do well under the new situation of township and village leaders inspire and help, and also share with you. A good play to create iron shoulders strong arms, to assume the burden be passed; only specific qualities, will it be possible in specific areas to create a world. In my view, village chiefs in the new situation, we must first have five basic quality. One ambition is to pioneer. \handsome.\h-minded can stimulate the flow of momentum to become brave and persistent, become quiet and powerful. Township and village party \hin their respective jurisdictions, political stability and economic and social development issues, decisions and orientation depends to a large extentbecause of your. Everybody in village chiefs and the positions, both the trust of the masses, the Organization's trust, more ability to you, fully affirmed the moral and other qualities. Therefore, we must always maintain the historical mission and social responsibility, and our ideal tree rooted in the hard work of the soil, with indomitable spirit, indomitable courage to open up a new situation of villages and towns. To have a feeling of closeness to the second. \he people and country.\business foundation in the people's blood in the people power people. Advanced decisions of the party cadres to the feelings of the people is an eternal theme. Fan Zhong-yan, called \njoy comfort about others\Banqiao's also wrote a \a Chai lay listening to the rustling of bamboo, the suspect is suffering. Cao County officials, little my, a total turn off. \l official even has so feelings, alone we is to\ng \s of people servant does? we more should always hold with on people of deep feelings, heart Department masses of leading visited tea, care masses of emotions thoughts complained, always insisted put masses of interests put in first, consciously from itself do up, from small do up, from masses most care, and most directly, and most reality of interests problem grabbed, real do love for people by Department, and right for people by with, and Lee for people by conspiracy to. Three with the fame of mind. \-indifferent not insist your dream, without serenity not go far.\s the sublimation of the soul. As ownship and village, be sure to maintain a normal state of mind, establish a correct viewpoint on power, position and values and Outlook, as fame is light like water, depending ... 50 km, also red and like hundreds of thousands of the KMT military combat, but he went on to collect a variety of newspapers and magazines, and then race against time to pore over. As long as the study of mind, it is not necessary to come to the library, workshops, into the villages, people learned farming techniques, problem-solving methods, participation in 超声波检测技术在混凝土结构检测控制中的应用
姜天闻（湖北汽车工业学院科技学院 材料工程系KT933-2 ）
【摘 要】 对超声波无损检测的特点做了相应的论述，并阐述了其作为无损评定
所具有的优越性和影响测强的因素。介绍了超声无损检测混凝土裂缝深度及其内部空洞常用的无损检测方法。
【关键词】 超声检测、优缺点、裂缝检测 、缺陷检测
前 言
超声法测强采用单一声速参数推定混凝土强度。当影响因素控制不严时，精度不如多因素综合法，但在某些无法测量回弹值及其他参数的结构或构件（如基桩、钢管混凝土等）中，超声法仍有其特殊的适应性。
1 超声波检测技术分析
声波的指向性比较好，其频率越高，指向性越好。超声波传播能量大，对各种材料的穿透力较强。超声波的声速、衰减、阻抗和散射等特性，为超声波的应用提供了丰富的信息。 超声检测具有适应性强、检测灵敏度高、对人体无害、设备轻巧、成本低廉，可即时得到探伤结果，适合在实验室及野外等各种环境下工作，并能对正在运行的装置和设备实行在线检查。超声法检测过程无损于材料、结构的组织和使用性能；直接在构筑物上测试验并推定其实际的强度；重复或复核检测方便，重复性良好[1]；超声法具有检测混凝土质地均匀性的功能，有利于测强测缺的结合，保证检测混凝土强度建立在无缺陷、均匀的基础上合理地评定混凝土的强度。
应用超声来进行无损检测也有其相应的缺点[2]。对于平面状的缺陷，例如裂纹，只要波束与裂纹平面垂直，就可以获得很高的缺陷回波信号。但是对于球面状的缺陷，例如空洞，假如空洞不是很大或分布不是较密集的话，就难以得到足够的回波信号或是其时间变化不明显；另外，对于各向非同性的材料，例如混凝土，相应会存在材料的离析，使得材料密度不均匀，这使得人们把离析误判为是内部的空洞而导致决策上的失误；对于表面缺陷的检测，超声波法的灵敏度要低得多，
conferences, learned superiors policies; reports, you can learn to deal with problems, art, just wanted to learn, to learn at any time. To continuously expand the scope of the study. The complexity and comprehensiveness of our work, decided to not only do we want to be \different areas of knowledge. Mastery of knowledge not only to have knowledge to rational analysis. This on requirements we, not only to learning national of route, and approach, and policy, also to learning national of legal, and regulations; not only to with political theory armed mind, also to with economic theory guide work; not only to read history, also to read history; not only to absorption SM of mirror, also to gets is of road; not only to from local learn, also to to outside learn; not only to to books learn, also to field study learn. Therefore, I would encourage you, and more to the outside world when I have time to take a look at, take a stroll, outside developments, learn other people's development approach, and then come back to guide our work. Second, we must think. \ng without thought to overshadow, thinking without learning is perilous.\of advancing with the times, forge ahead, often reflect themselves in adapting to the new situation on whether there are delays, have anything to fear in the reform and innovation, whether in terms of accelerating the development of a relaxation, keep promising State of mind. In order to do investigations, investigations is the road to heaven, God disposes of the base. To wants to real heard truth, and justice to truth, and get truth, received effectiveness, on must in-depth actual, and outreach, and in-depth masses, worship masses for Division, and masses heart, with masses with discussion everyone care of problem, listening they of calls, understand they of mood, feel they of suffering, summary they of experience, concentrated they of wisdom, especially on masses mosthope, and most urgent, and most worries, and most complained of hot, and difficulties and focus problem, more to active research, caught not put. Dare to innovate, in our work, often remain \d way doesn't work, the new approach would not\on, the reason, the key is that many people know that copying other people's ideas, mechanically, using someone else's old ways. To change this predicament, requires us to break the shackles of traditional concepts to overcome conservative, conformist, good at finding new problems and to accept new things, summarize new experience, new ideas, developing new programmes and Maverick, a new approach to solve problems, speed up development. Especially in implement superior policy spirit of process in the, both implementation, and cannot mechanically, to to extraordinary of courage and develop enterprising of spirit, put flexibility and principle combined up, put superior of spirit and local reality combined up, Yong conspiracy to breakthrough of policy, and exercise innovation of lift, developed out development works of, and grass-roots welcomes ofdifficult, not hating; blueprints, not rhetoric; words and simple, but full of love, truth, passion, entrepreneurial passion. Take this opportunity, my inspirational quotes Li Dazhao's classic \cialise in uplifting blend with the article\ith a view on how to do well under the new situation of township and village leaders inspire and help, and also share with you. A good play to create iron shoulders strong arms, to assume the burden be passed; only specific qualities, will it be possible in specific areas to create a world. In my view, village chiefs in the new situation, we must first have five basic quality. One ambition is to pioneer. \handsome.\can stimulate the flow of momentum to become brave and persistent, become quiet and powerful. Township and village party \n their respective jurisdictions, political stability and economic and social development issues, decisions and orientation depends to a large extent because of your. Everybody in village chiefs and the positions, both the trust of the masses, the Organization's trust, more ability to you, fully affirmed the moral and other qualities. Therefore, we must always maintain the historical mission and social responsibility, and our ideal tree rooted in the hard work of the soil, with indomitable spirit, indomitable courage to open up a new situation of villages and towns. To have a feeling of closeness to the second. \people and country.\ss foundation in the people's blood in the people power people. Advanced decisions of the party cadres to the feelings of the people is an eternal theme. Fan Zhong-yan, called \njoy comfort about others\ng Banqiao's also wrote a \a Chai lay listening to the rustling of bamboo, the suspect is suffering. Cao County officials, little my, a total turn off. \ official even has so feelings, alone we is to\of people servant does? we more should always hold with on people of deep feelings, heart Department masses of leading visited tea, care masses of emotions thoughts complained, always insisted put masses of interests put in first, consciously from itself do up, from small do up, from masses most care, and most directly, and most reality of interests problem grabbed, real do love for people by Department, and right for people by with, and Lee for people by conspiracy to. Three with the fame of mind. \nsist your dream, without serenity not go far.\o fame is morality, is the sublimation of the soul. As Township and village, be sure to maintain a normal state of mind, establish a correct viewpoint on power, position and values and Outlook, as fame is light like water, depending ... 50 km, also red and like hundreds of thousands of the KMT military combat, but he went on to collect a variety of newspapers and magazines, and then race against time to pore over. As long as the study of mind, it is not necessary to come to the library, workshops, into the villages, people learned farming techniques, problem-solving methods, participation i湖北汽车工业学院科技学院 检测技术与控制工程（论文） 但超声无损检测方法可以较为精确的确定混凝土表面的裂缝深度。
2 测量参数
混凝土超声检测目前主要是采用所谓“穿透法”，即用发射换能器重复发射超声脉冲波，让超声波在所检测的混凝土中传播，然后由接收换能器接收。被接收到的超声波转化为电信号后再经超声仪放大显示在示波屏上，用超声仪测量直接收到的超声信号的声学参数。当超声波经混凝土中传播后，它将携带有关混凝土材料性能、内部结构及其组成的信息。准确测定这些声学参数的大小及变化,可以推断混凝土的性能内部结构及其组成情况。
2.1声速
声速即超声波在混凝土中传播的速度。它是混凝土超声检测中一个主要参数。混凝土的声速与混凝土的弹性性质有关，也与混凝土内部结构（孔隙、材料组成）有关。不同组成的混凝土，其声速各不相同。一般说来，弹性模量越高，内部越是致密，其声速也越高。而混凝土的强度也与它的弹性模量、它的孔隙率（密实性）有密切关系。因此，对于同种材料与配合比的混凝土，强度越高，其声速也越高。若混凝土内部有缺陷（孔洞、蜂窝体），则该处混凝土的声速将比正常部位低。当超声波穿过裂缝而传播时，所测得的声速也将比无裂缝处声速有所降低。总之，混凝土声速值能反映混凝土的性能及其内部情况。
2.2振幅
接收波振幅通常指首波，即第一个波前半周的幅值，接收波的振幅与接收换能器处被测介质超声声压成正比，所以接收波振幅值反映了接收到的声波的强弱。在发射出的超声波强度一定的情况下，振幅值的大小反映了超声波在混凝土中衰弱的情况。而超声波的衰减情况又反映了混凝土粘塑性能。混凝土是弹粘塑性体，其强度不仅和弹性性能有关，也和其粘塑性能有关，因此，衰减大小，即振幅高低也能在一定程度反映混凝土的强度。对于内部有缺陷或裂缝的混凝土，由于缺陷、裂缝使超声波反向或绕射，振幅也将明显减小，因此，振幅值也是判断缺陷与裂缝的重要指标。由于振幅值的大小还取决于仪器设备性能、所处的状态，耦合状况以及测距的大小，所以很难有统一的度量标准，目前只是作为同条件（同
conferences, learned superiors policies; reports, you can learn to deal with problems, art, just wanted to learn, to learn at any time. To continuously expand the scope of the study. The complexity and comprehensiveness of our work, decided to not only do we want to be \different areas of knowledge. Mastery of knowledge not only to have knowledge to rational analysis. This on requirements we, not only to learning national of route, and approach, and policy, also to learning national of legal, and regulations; not only to with political theory armed mind, also to with economic theory guide work; not only to read history, also to read history; not only to absorption SM of mirror, also to gets is of road; not only to from local learn, also to to outside learn; not only to to books learn, also to field study learn. Therefore, I would encourage you, and more to the outside world when I have time to take a look at, take a stroll, outside developments, learn other people's development approach, and then come back to guide our work. Second, we must think. \ng without thought to overshadow, thinking without learning is perilous.\of advancing with the times, forge ahead, often reflect themselves in adapting to the new situation on whether there are delays, have anything to fear in the reform and innovation, whether in terms of accelerating the development of a relaxation, keep promising State of mind. In order to do investigations, investigations is the road to heaven, God disposes of the base. To wants to real heard truth, and justice to truth, and get truth, received effectiveness, on must in-depth actual, and outreach, and in-depth masses, worship masses for Division, and masses heart, with masses with discussion everyone care of problem, listening they of calls, understand they of mood, feel they of suffering, summary they of experience, concentrated they of wisdom, especially on masses mosthope, and most urgent, and most worries, and most complained of hot, and difficulties and focus problem, more to active research, caught not put. Dare to innovate, in our work, often remain \d way doesn't work, the new approach would not\on, the reason, the key is that many people know that copying other people's ideas, mechanically, using someone else's old ways. To change this predicament, requires us to break the shackles of traditional concepts to overcome conservative, conformist, good at finding new problems and to accept new things, summarize new experience, new ideas, developing new programmes and Maverick, a new approach to solve problems, speed up development. Especially in implement superior policy spirit of process in the, both implementation, and cannot mechanically, to to extraordinary of courage and develop enterprising of spirit, put flexibility and principle combined up, put superior of spirit and local reality combined up, Yong conspiracy to breakthrough of policy, and exercise innovation of lift, developed out development works of, and grass-roots welcomes ofdifficult, not hating; blueprints, not rhetoric; words and simple, but full of love, truth, passion, entrepreneurial passion. Take this opportunity, my inspirational quotes Li Dazhao's classic \lise in uplifting blend with the article\h a view on how to do well under the new situation of township and village leaders inspire and help, and also share with you. A good play to create iron shoulders strong arms, to assume the burden be passed; only specific qualities, will it be possible in specific areas to create a world. In my view, village chiefs in the new situation, we must first have five basic quality. One ambition is to pioneer. \handsome.\h-minded can stimulate the flow of momentum to become brave and persistent, become quiet and powerful. Township and village party \hin their respective jurisdictions, political stability and economic and social development issues, decisions and orientation depends to a large extentbecause of your. Everybody in village chiefs and the positions, both the trust of the masses, the Organization's trust, more ability to you, fully affirmed the moral and other qualities. Therefore, we must always maintain the historical mission and social responsibility, and our ideal tree rooted in the hard work of the soil, with indomitable spirit, indomitable courage to open up a new situation of villages and towns. To have a feeling of closeness to the second. \he people and country.\business foundation in the people's blood in the people power people. Advanced decisions of the party cadres to the feelings of the people is an eternal theme. Fan Zhong-yan, called \njoy comfort about others\Banqiao's also wrote a \a Chai lay listening to the rustling of bamboo, the suspect is suffering. Cao County officials, little my, a total turn off. \l official even has so feelings, alone we is to\ng \s of people servant does? we more should always hold with on people of deep feelings, heart Department masses of leading visited tea, care masses of emotions thoughts complained, always insisted put masses of interests put in first, consciously from itself do up, from small do up, from masses most care, and most directly, and most reality of interests problem grabbed, real do love for people by Department, and right for people by with, and Lee for people by conspiracy to. Three with the fame of mind. \-indifferent not insist your dream, without serenity not go far.\s the sublimation of the soul. As ownship and village, be sure to maintain a normal state of mind, establish a correct viewpoint on power, position and values and Outlook, as fame is light like water, depending ... 50 km, also red and like hundreds of thousands of the KMT military combat, but he went on to collect a variety of newspapers and magazines, and then race against time to pore over. As long as the study of mind, it is not necessary to come to the library, workshops, into the villages, people learned farming techniques, problem-solving methods, participation in 一仪器、同一状态、同一测距）下相对比较用[3]。
2.3频率
如前所述，在超声检测中，由电脉冲激发出的声脉冲信号是复频超声脉冲波。它包含了一系列不同频率成分的余弦波分量。这种含有各种频率成分的超声波在传播过程中，高频成分首先衰减（被吸收、散射）。因此，可以把混凝土看作是一种类似高频滤器的介质。超声波愈往前传播，其所包含的高频分量愈少，则主频率也逐渐下降。这已为不同测距的试验及频谱分析结果充分证实。主频率下降的多少除与传播距离有关外，主要取决于混凝土本身的性质（质量、强度）和内部是否存在缺陷、裂缝等。因此，测量超声波通过混凝土后频率的变化可以判断混凝土质量和内部缺陷、裂缝等情况。
要准确细致地测量和分析接收波各频率成分变化，须采用频谱分析的途径，这需要对波形采样后送入计算机，进行快速傅利叶变换（FFT），获得频谱图。目前的数字式超声仪具有这一功能。下面将提出用超声仪直接测量接收波主频率的简易有效的方法。
和振幅一样，接收波主频率的绝对值大小不仅取决于被测混凝土的性质的内部情况，也和所用仪器设备、传播距离有关，目前也只能用同于同条件下的相对比较用。
2.4波形
这里指的波形第指在显示屏上显示的接收波波形。当超声波在传播过程中碰到混凝土内部缺陷、裂缝或异物时，由于超声波的绕射、反射和传播路径的复杂化，直达波、反射波、绕射波等各类波相继到达接收换能器，它们的频率和相位各不相同。这些波的叠加有时会使波形畸变。因此，对接收波波形的分析、研究有助于对混凝土内部质量及缺陷的判断。鉴于波形的变化受各种因素的影响，目前对波形的研究只能作一般的观察，记录。
这里还要说明的是，通常所用的纵波换能器所发射的超声脉冲波不仅有纵波成分也有横波成分，即便是较纯的纵波，在通过混凝土内各声学界面后也有部分转化为横波。因此，接收到的一串波形中，既有纵波也有横波。若邻近表面测量时，还有表面波。但是由于横波与表面波传播速度较纵波慢，所以在首波之后一定时刻才出现并和纵波的后续波叠加在一起。如果波形分析与研究也包括了这一部
conferences, learned superiors policies; reports, you can learn to deal with problems, art, just wanted to learn, to learn at any time. To continuously expand the scope of the study. The complexity and comprehensiveness of our work, decided to not only do we want to be \different areas of knowledge. Mastery of knowledge not only to have knowledge to rational analysis. This on requirements we, not only to learning national of route, and approach, and policy, also to learning national of legal, and regulations; not only to with political theory armed mind, also to with economic theory guide work; not only to read history, also to read history; not only to absorption SM of mirror, also to gets is of road; not only to from local learn, also to to outside learn; not only to to books learn, also to field study learn. Therefore, I would encourage you, and more to the outside world when I have time to take a look at, take a stroll, outside developments, learn other people's development approach, and then come back to guide our work. Second, we must think. \ng without thought to overshadow, thinking without learning is perilous.\of advancing with the times, forge ahead, often reflect themselves in adapting to the new situation on whether there are delays, have anything to fear in the reform and innovation, whether in terms of accelerating the development of a relaxation, keep promising State of mind. In order to do investigations, investigations is the road to heaven, God disposes of the base. To wants to real heard truth, and justice to truth, and get truth, received effectiveness, on must in-depth actual, and outreach, and in-depth masses, worship masses for Division, and masses heart, with masses with discussion everyone care of problem, listening hey of calls, understand they of mood, feel they of suffering, summary they of experience, concentrated they of wisdom, especially on masses mosthope, and most urgent, and most worries, and most complained of hot, and difficulties and focus problem, more to active research, caught not put. Dare to innovate, in our work, often remain \d way doesn't work, the new approach would not\on, the reason, the key is that many people know that copying other people's ideas, mechanically, using someone else's old ways. To change this predicament, requires us to break the shackles of traditional concepts to overcome conservative, conformist, good at finding new problems and to accept new things, summarize new experience, new ideas, developing new programmes and Maverick, a new approach to solve problems, speed up development. Especially in implement superior policy spirit of process in the, both implementation, and cannot mechanically, to to extraordinary of courage and develop enterprising of spirit, put flexibility and principle combined up, put superior of spirit and local reality combined up, Yong conspiracy to breakthrough of policy, and exercise innovation of lift, developed out development works of, and grass-roots welcomes ofdifficult, not hating; blueprints, not rhetoric; words and simple, but full of love, truth, passion, entrepreneurial passion. Take this opportunity, my inspirational quotes Li Dazhao's classic \cialise in uplifting blend with the article\ith a view on how to do well under the new situation of township and village leaders inspire and help, and also share with you. A good play to create iron shoulders strong arms, to assume the burden be passed; only specific qualities, will it be possible in specific areas to create a world. In my view, village chiefs in the new situation, we must first have five basic quality. One ambition is to pioneer. \handsome.\can stimulate the flow of momentum to become brave and persistent, become quiet and powerful. Township and village party \n their respective jurisdictions, political stability and economic and social development issues, decisions and orientation depends to a large extent because of your. Everybody in village chiefs and the positions, both the trust of the masses, the Organization's trust, more ability to you, fully affirmed the moral and other qualities. Therefore, we must always maintain the historical mission and social responsibility, and our ideal tree rooted in the hard work of the soil, with indomitable spirit, indomitable courage to open up a new situation of villages and towns. To have a feeling of closeness to the second. \people and country.\ss foundation in the people's blood in the people power people. Advanced decisions of the party cadres to the feelings of the people is an eternal theme. Fan Zhong-yan, called \njoy comfort about others\ng Banqiao's also wrote a \a Chai lay listening to the rustling of bamboo, the suspect is suffering. Cao County officials, little my, a total turn off. \ official even has so feelings, alone we is to\of people servant does? we more should always hold with on people of deep feelings, heart Department masses of leading visited tea, care masses of emotions thoughts complained, always insisted put masses of interests put in first, consciously from itself do up, from small do up, from masses most care, and most directly, and most reality of interests problem grabbed, real do love for people by Department, and right for people by with, and Lee for people by conspiracy to. Three with the fame of mind. \nsist your dream, without serenity not go far.\o fame is morality, is the sublimation of the soul. As Township and village, be sure to maintain a normal state of mind, establish a correct viewpoint on power, position and values and Outlook, as fame is light like water, depending ... 50 km, also red and like hundreds of thousands of the KMT military combat, but he went on to collect a variety of newspapers and magazines, and then race against time to pore over. As long as the study of mind, it is not necessary to come to the library, workshops, into the villages, people learned farming techniques, problem-solving methods, participation i湖北汽车工业学院科技学院 检测技术与控制工程（论文） 分，那么情况将更为复杂，所以，通常的波形分析与研究大多集中于波前部的纵波，而且最好是不受边界影响的直达纵波。
3 超声检测混凝土强度的主要影响因素
超声法检测混凝土强度，主要是通过测量在测距内超声传播的平均声速来推定混凝土的强度。可见，“测强”精度 高低与超声声速读取值的准确与否是密切相关的，换句话说，正确运用超声声速推定混凝土强度和评价混凝土质量， 从事检测工作的技术人员必须熟悉影响声速测量的因素，在检测中自觉地排除这些影响。
3.1横向尺寸效应
关于试件横向尺寸的影响，在测量声速时必须注意。通常，纵波速度是指在无限大介质中测得，随着试件横向尺寸减小，纵波速度可能向杆、板的声速或表面波速度转变，即声速比无限大介质中纵波声速为小。
当横向最小尺寸d≥2λ（λ为波长）时，传播速度与大块体中纵波速度值相当。 当λ＜d＜2λ时，可使传播速度降低2.5%～3%
当0.2＜λd＜λ时，传播速度变化较大，约降低6%～7%，在这个区间里测量时，估计强度的误差可能达30%～40%，这是不允许的。
3.2温度和湿度的影响
混凝土处于环境温度为5℃～30℃情况下，因温度升高引起的速度减小值不大；当环境在40℃～60℃范围内，脉冲速度值约降低5%，这可能是由于混凝土内部的微裂缝增多所致。
温度在0℃以下时，由于混凝土中的自由水结冰，使脉冲速度增加（自由水的V=1.45㎞/s,冰的 V=3.50km/s）。
混凝土的抗压强度随其含水率的增加而降低，而超声波传播速度v随孔隙被水填满面逐渐增高。饱水混凝土的含水率增高4%，传播速度V相应增大6%。速度的变化特性取决于混凝土的结构，随着混凝土孔隙率的增大，干混凝土中超声波传播速度的差异也增大。水中养护的混凝土具有较高的水化度并形成大量的水化产物，超声波传播速度对此产物的反映大于空气中硬化的混凝土；水中养护的混凝土，水分渗透并填充了混凝土的孔隙，由于超声在水里传播速度为1.45km/s，
conferences, learned superiors policies; reports, you can learn to deal with problems, art, just wanted to learn, to learn at any time. To continuously expand the scope of the study. The complexity and comprehensiveness of our work, decided to not only do we want to be \different areas of knowledge. Mastery of knowledge not only to have knowledge to rational analysis. This on requirements we, not only to learning national of route, and approach, and policy, also to learning national of legal, and regulations; not only to with political theory armed mind, also to with economic theory guide work; not only to read history, also to read history; not only to absorption SM of mirror, also to gets is of road; not only to from local learn, also to to outside learn; not only to to books learn, also to field study learn. Therefore, I would encourage you, and more to the outside world when I have time to take a look at, take a stroll, outside developments, learn other people's development approach, and then come back to guide our work. Second, we must think. \ng without thought to overshadow, thinking without learning is perilous.\of advancing with the times, forge ahead, often reflect themselves in adapting to the new situation on whether there are delays, have anything to fear in the reform and innovation, whether in terms of accelerating the development of a relaxation, keep promising State of mind. In order to do investigations, investigations is the road to heaven, God disposes of the base. To wants to real heard truth, and justice to truth, and get truth, received effectiveness, on must in-depth actual, and outreach, and in-depth masses, worship masses for Division, and masses heart, with masses with discussion everyone care of problem, listening they of calls, understand they of mood, feel they of suffering, summary they of experience, concentrated they of wisdom, especially on masses mosthope, and most urgent, and most worries, and most complained of hot, and difficulties and focus problem, more to active research, caught not put. Dare to innovate, in our work, often remain \d way doesn't work, the new approach would not\on, the reason, the key is that many people know that copying other people's ideas, mechanically, using someone else's old ways. To change this predicament, requires us to break the shackles of traditional concepts to overcome conservative, conformist, good at finding new problems and to accept new things, summarize new experience, new ideas, developing new programmes and Maverick, a new approach to solve problems, speed up development. Especially in implement superior policy spirit of process in the, both implementation, and cannot mechanically, to to extraordinary of courage and develop enterprising of spirit, put flexibility and principle combined up, put superior of spirit and local reality combined up, Yong conspiracy to breakthrough of policy, and exercise innovation of lift, developed out development works of, and grass-roots welcomes of
检测技术论文 2 - 图文
