振动测试的教学实验设计分析论文

振动测试的教学实验设计分析论文（通用6篇）

篇1：振动测试的教学实验设计分析论文

机械测试技术实验

实 验 报 告

机械转子试验台的振动和噪声测试及分析综合实验

班级：机自04

西安交通大学机械基础实验教学中心

机械转子试验台的振动和噪声测试及分析综合实验

一实验目的：

针对机械转子实验台，能够较熟练地掌握机械动态信号（振动、噪声等）测试系统设计、测试系统搭建、数据采集及信号处理的方法和技术。

二 实验要求：

要求学生自行设计和构建机械转子实验台在工作条件下的动态信号（振动、噪声等）测试方法，利用计算机测试系统采集实验台的振动和噪声动态信号，并且通过对测量的动态信号处理，分析转子实验台在工作中的动态特性。

三 实验过程：

实验分为四个部分通过对轴心轨迹的测量来观察转子不平衡引起的回转运动；测量转子转动引起的振动的时域和频域分析；测量转动噪声的时域和频域；最后进行噪声和振动的相干性分析，判断实验的在一定频率下的噪声是否由转子的振动引起。

四 实验内容：

a.针对转子实验台对象，按照机械动态特性测试要求，完成机械振动和噪声的计算机测试系统设计；

b.选用合适的振动和噪声测试传感器及其信号调理装置；

c.构建计算机测试系统，掌握振动和噪声信号分析软件使用方法； d.自主完成转子实验台振动和噪声的测量、信号采集；

e.通过信号分析，得出转子实验台在不同转速下的振动和噪声的时域波形、频谱；并对转子实验台的动态特性进行分析评价。

五提供的主要仪器：

机械动态信号测量与信号采集分析系统机械转子实验台 加速度传感器

电涡流位移传感器光电传感器 噪声测量仪计算机

速度传感器 六 实验数据及分析 6.1转子轴心轨迹测试实验

轴轨迹是指转子轴心相对于试验台在与轴垂直的平面内的运动轨迹，通过两个互为的90度垂直的电涡流传感器测出在X轴和Y轴的振动矢量的叠加。若转子各方向的弯曲刚度和支承刚度相同，则轴心轨迹为圆；若不相等，则为椭圆或其他复杂的图形。以下是实验所得图像：

通过图像可知，轴心轨迹图不是圆，而是一个光滑的曲线，可知轴正在各个方向振动的幅值不一样，也即转子转动不平衡。

6.2转子振动分析

反映转子振动的幅值在一定转速下随时间变化的规律，我们在不同的两个转 速下测出转子在振动时的幅值关系，如下图 6.2.1时域分析图像如下

n=1500rpm

n=2018rpm

6.3.2转子振动的频谱分析 n=3012

由图看出，振动信号表现出明显的谐波特性。主要的峰值出现在工频处（3000/60=50Hz）及二倍工频处，其他峰值所对应的频率也基本为工频的谐波，振动信号的这种的谐波特性，说明引起转子振动的主要激励源为以工频为工作周期运动的机构或部件，对于此实验来说即为转子在转速3000rpm下的由于转子转动的不平衡引起的。

6.3机械转子噪声分析

6.3.1机械转子噪声的时域分析

由于噪声是一种随机信号，即无法用确定的时间函数来表示的信号。在时域图中，它的大小随时间随机变化，加上环境噪声的不规律影响，得到噪声随时间的变化时很不稳定的随机信号。

6.3.机械转子振动噪声的频域分析

由噪声的频域分析图像可以看出，噪声信号在低频段的能量交大，在中频段和高频段能量较小。由此，我们假设低频段的噪声主要是由机械转子的振动引起，而中频段和高频段主要是由于环境噪声引起。

低频段噪声信号是由环境噪声和转子振动噪声叠加起来的，因此应该具有比较大的能量。

6.4 机械转子振动和噪声的相干性分析

图为横坐标为不同的频率，纵坐标为相干系数表征在不同频率下的振动和噪声的相干性，由图可知，在整个分频带内，有许多频率对应的相干系数都较大，在大概35Hz（转速为2018rpm,工频为34Hz）的时候我们看到相干函数值0.95，说明振动和噪声的相干性很好。故可知该噪声和机械转子的振动在工频处有很大程度的相关程度，因此若要降低噪声，应从抑制转子的振动方面考虑。而转子振动由于其不平衡引起。七实验总结

由于本次实验没有很多的指导，不像之前的实验，我们需要自己做出实验方案，搭建实验测试系统，这对我们温习课本中的知识很是重要；通过本次实验，更加熟悉了解电涡流传感器、光电传感器等的原理及其在工业控制中的实际应用； 通过测试系统各部分的搭建，对于信号的采集、调理、分析有了进一步的认识； 通过对机械转子的研究，深入了解转子轴心的震动、转子噪声信号的产生机理，并通过相关分析研究噪声和震动的相干关系；

篇2：振动测试的教学实验设计分析论文

1、引言在传统的实验教学中，实验教师要求学生在每次实验前对将要做的实验进行预习，并完成实验预习报告。在实际教学中教师发现，有很多同学虽然预习报告写得很好，但对实验的基本知识和内容并不了解，原因是部分学生的实验预习报告是抄袭实验讲义或其它同学而来的。那么如何有效地督促学生进行实验前的预习，达到真正的实验预习目的就是一个急需解决的难题。笔者提出了一个利用现代网络技术，进行网上预习测试的方法来解决这一难题。具体的做法是：在每次实验前，学生通过IE浏览器验证登录到网上实验预习测试系统中，完成网上测试并由计算机立即给出成绩。这样就能轻松完成测试任务。

2、网上实验预习测试系统的设计

网上实验预习测试系统设计时必须考虑以下因素：一是系统要简单易操作。该系统只是考查学生的实验预习情况，如是否了解本次实验所需仪器、实验的基本原理、基本概念等，所以考题要求简单、明了，系统也要简单易操作。二是要进行时间限定。要求每位学生的考试不超过二十分钟;三是要求计算机能够立即自动评卷;四是要求考试系统能随机组题，并产生多套试卷;五是考试系统要有一定的安全性、平台通用等。

2.1系统设计

本系统在体系结构上采用了基于B/S方式的Web三层模型：在此模型中，客户机上运行的应用程序是IE浏览器，中间层是Web服务器和服务器扩展程序，底层是数据库服务器。当用户通过浏览器向网络上的服务器发出请求时，Web服务器将其转换成数据库服务器能够接受的形式，再通过数据网关与数据库进行数据交换，对数据库的访问和应用程序的执行在服务器上完成。在B/S三层体系结构下,表示层、应用逻辑层、数据服务层被分为三个相对独立的单元，如图1所示。

表示层(Presentation)即Web浏览器。该层位于客户端，它的任务是向Web服务器提出服务请求， Web服务器对用户进行身份验证后用HTTP协议把所需的主页传送给客户端，并把它显示在Web浏览器上。

应用逻辑层(BusinessLogic)即具有应用程序扩展功能的Web服务器。该层中包含系统的事务处理逻辑，位于Web服务器端。它的任务是接受用户的请求。其过程是：首先执行相应的扩展应用程序与数据库进行连接，通过SQL等方式向数据库提出数据处理申请，然后等待数据库服务器将数据处理的结果提交给Web服务器，最后由Web服务器传送回客户端。

数据服务层(DataService)即数据库服务器。该层位于数据库服务器端。它的任务是接受Web服务器对数据库操作的请求，实现对数据库查询、修改、更新等操作，把运行结果提交给Web服务器。

2.2功能设计

本系统在功能上要求简单方便，系统分为学生和教师两个模块。学生模块完成学生登录验证、密码修改、网上考试的功能。教师模块由用户管理、题库管理、随机组卷、修改密码四个模块构成。系统功能结构如图2所示。主要模块功能介绍如下：

学生模块是考试系统的一个核心模块，其功能对登录的学生进行验证，验证后允许其参加考试，并由系统自动进行倒计时，时间一到立即锁定计算机，不允许考生继续答题;另一个重要功能是实现考生的考试结果的提交功能，在这个功能中，考生只要确定自己答卷完毕，按一个确定键即可完成提交和自动评分功能。自动评分过程是：系统收到考生提交的答卷后，根据题目在试题库中的编号找出其标准答案，对照标准答案对考生答卷进行批改并计分，把成绩返回给考生。

教师模块中的重要模块有题库管理、随机组卷、用户管理三个模块。用户管理模块主要实现用户的添加、查询、浏览、编辑、删除功能。题库管理模块是教师模块中的核心模块之一，主要由试题检索、知识点管理、选择题管理和填空题管理模块组成。完成试题检索功能，知识点的添加、删除、编辑、浏览功能，选择题和填空题的添加、删除、编辑、浏览功能等。随机组卷功能经过设定考试名称、总分、题型分布、分值分布、知识点范围、考试时间和试卷有效期，再设定参加考试的.学生就可以为每个考生随机组出一套试卷。

2.3数据库设计

考试系统中数据库设计是考试系统开发成功关键。根据前面提出的要求，在分析考试系统的数据流后，经过认真的数据库设计，得出了一系列高效的、明确的数据表。其中对于题库的设计是按一种题型一个表的方案来设计的，由于自动评分、考试时间等条件的限制以及功能简化的要求，本系统中只采用了答案唯一的选择题和填空题表。本系统中用到的重要的数据表有：题库表、试卷表、考生表、知识点表、试卷考生表、教师表等六种数据表。主要数据表字段意义及关联关系如图3所示：

该图中表1中的知识点字段关联不同题型的数据表如表2中的知识点字段，通过该字段，对考题抽取范围的知识点进行限制;表3试卷表中不同题型的知识点范围字段也分别与不同题型表中的知识点字段字段进行关联，系统出卷时受这些关联字段的条件限制。表3中试卷号字段与表4中试卷号字段关联，将抽取的试卷分配给不同考生。表4试卷考生表中的学号字段与表5学生表中的学号字段关联，以此获得学生信息。

2.4安全设计

考试系统安全设计十分重要，在设计时从以下几个方面考虑了系统的安全性。

登录验证。本系统在考生登录和管理员登录时都必须经过密码验证，只有验证通过方可登录，否则不允许登录。用户登录后，系统会自动记录用户的登陆时间、IP地址，以及离线时间等信息。

数据库安全考虑。为了防止题库文件被非法下载，采用数据库改名方法来控制。

页面安全控制。每一个页面通过一个会话级变量session(“logon”)验证是否为合法用户，如果不合法，则自动转到登陆页面。通过程序控制服务器缓存页面的读取，这样保证用户离开考试后，非法用户不能利用服务器缓存的页面非法进入系统。另外，还进行响应时间控制等。

3、网上预习测试系统的实现技术

网上预习测试系统主要采用ASP加数据库技术来实现。系统采用动态网站编程语言ASP内嵌VBScript、JavaScript脚本，查询语言采用通用SQL查询语句。后台数据库选用了微软的ACCESS，因为本系统数据量不大，ACCESS数据库可以满该系统需要。可视化网站制作工具采用流行的Dreamweaver4.0软件。

ASP技术是目前网站开发中常用的并为编程者所熟知的一种技术，通过使用ASP的组件和对象技术，用户可以直接使用ActiveX组件调用对象方法和属性，以简单的方式实现强大功能、动态、交互的高性能WEB应用程序。并且ASP程序运行在服务器端，安全性好。运用ASP提供的对象,可轻松实现服务器与客户端的信息交换、客户端之间的信息交换等。在ASP程序中，使用ADO组件来访问后台数据库。运用结构化查询语言SQL(Structured Query Language)来对数据库进行各种编辑、插入、更新、创建等操作。

4、结束语

篇3：振动测试的教学实验设计分析论文

关键词：结构动力学,振动测试,有限元分析

为适应向职业教育转型, 成为应用型技术人才, 实践学习对于当前大学生尤为重要。结构力学是土木工程专业的核心课程。由于课时、实验条件等限制, 结构力学[1]课程没有设置相应的结构试验环节。针对结构动力学部分计算繁琐的特点, 采取理论与实践结合的教与学的方式, 可以提高学生的积极性和创造性。对工程结构而言, 结构实验是研究和发展结构计算理论不可缺少的重要环节。

1 实验手段在课程中的必要性

结构的动力特性包括结构的自振频率、阻尼系数和振型等一些基本参数或振动模态参数, 是反映结构本身所固有的动力性能。由结构形式、质量分布、结构刚度、材料性质、构造连接等因素决定, 与外荷载无关。

对结构进行动力分析的目的是保证结构在整个使用周期, 在可能发生的动荷载作用下能够正常工作, 并保持一定的可靠度。这就要求我们寻找结构在任意动荷载作用下随时间而变化的响应。然而多自由度体系的计算相对比较复杂, 因而也就不可避免地要涉及到结构动力实验的测试技术[2]。

2 设计结构力学振动测试实验的目的

在结构力学课程中, 关于动力特性的计算属于动力学中的核心内容。然而该部分内容涉及到一系列的简化和推导, 内容涵盖了线性代数、高等数学中的知识, 计算过程比较复杂。采用实验的方法作为辅助的实践性手段, 可以达到更好的教学及学习效果。

本次设计的振动测试实验要求达到以下目的:

1) 了解测定结构动力特性的基本原理, 掌握通过人工激振法和环境随机振动法测试不同自由度系统的动力特性 (固有频率、阻尼及振型) 的方法;2) 熟悉常用结构动力特性测试系统的组成和相关仪器的使用方法;3) 通过实验测定三层框架结构的前三阶频率及阻尼比;4) 掌握ETABS建模及时程分析的运用;5) 掌握DASP分析软件, 并对实测数据进行结构动力特性分析。

3 振动测试实验设计

3.1 实验设计

试验主要仪器及设备:1) 力锤:用来发生激振信号。2) 加速度传感器:将被测系统的机械振动量 (加速度) 转换成电量。3) 电荷放大器:将加速度传感器输出的较小的电荷信号放大成可供检测的电压信号。4) 数据采集与分析系统 (DASP) :记录和分析结构振动的各个参数。5) 实验模型:空气动力学试验台。

3.2 实验实施

1) 自振频率的测定。a.打开DASP专业版, 选择使用采集仪1:[v618]INV306DF。b.点击采样进入计算机监视状态, 在此界面点击示波进入示波状态。c.设置参数:基本参数:试验名设置为三层框架模型, 试验号设置为1, 自动增加;采样频率取125;数据路径按照自定义文件夹设置。通道参数:通道Ch01;工程单位g;标定值根据所用传感器设置为206;增益倍数设置为4, 根据所采数据是否出现削峰选择合适增益倍数;虚拟扩展通道, 增加通道一的二次积分, 以得到时间位移曲线。开始条件:选择信号触发, 触发电平设置为400 m V。结束条件:采样结束方式按时间20 s。d.观察显示器上测点波形的幅值及频率变化现象, 并用手轻轻触摸结构进行体验。e.由测量数据可以绘制出幅频曲线 (计算机自动绘制) 。f.根据幅频曲线进行自谱分析确定三阶固有频率。

2) 阻尼的测定。在自由振动法下测定结构自振频率的同时数据分析采集仪器通过半功率带宽法可以对结构的阻尼进行计算, 得到阻尼比。

3) 对比数据。在用实验仪器测得结构各动力特性后再用ETABS建立三层框架模型, 对其进行时程分析, 得出动力特性指标, 将两者得到的数据进行对比。

3.3 试验数据处理及分析

1) 实验测得三层框架模型的频率曲线及阻尼比见表1。

2) ETABS[3]分析频率结果。将模型简化为框架模型参数建模:由ETABS分析结果得该三层框架结构的第一自振频率为6.402, 第二自振频率为17.212, 第三自振频率为23.753。

3) 阻尼比的计算。利用自由振动法一般只能得到结构基本阻尼, 计算公式如下:

由实验数据自由振动时程曲线得相邻一个周期的振幅α1=2 878.87, α2=-1 069.41。

代入公式得ζ=0.100 4与实验结果ζ=0.110 0对比结果相近。

4) 结果对比 (见表1) 。

5) 实验分析。根据实验目的, 需要理论计算结果与实验实测结果匹配, 以达到实验目的。在理论分析过程中, 在ETABS软件建立模型过程中, 模型的参数的设置正确与否直接影响着实验结果的准确性。例如模型中框架柱弹性模量设置和结构体系的选择非常重要, 结构自振频率与结构的质量和刚度密切相关。结构体系的选择直接影响实验结果, 当按照实际结构建立模型, 分析得出的结果与实测结果相差很大, 经过分析, 可能是由于软件分析中将结构视为板柱模型所致。将模型中板简化为同质量梁, 以简化为框架结构, 通过分析得出的结果与实测结果近似。

4 结语

在结构力学课程中设置实验实践, 提高了学生理论应用到实践的能力, 并使得对专业知识的认识起到很大的提高作用, 锻炼了学生提出问题, 分析问题, 解决问题的能力, 对学生的综合素质起到很大提高作用。通过实验与理论分析的对比, 使学生对基本概念有更深的理解, 对专业软件的运用也更加熟练。在理论性强的力学课程中设计实验课程, 提高了学生学习兴趣, 教与学的效果得到大幅度提高。

参考文献

[1]龙驭球.结构力学Ⅱ[M].北京:高等教育出版社, 2001.

[2]熊仲明.土木工程结构试验[M].北京:中国建筑工业出版社, 2006.

篇4：振动测试的教学实验设计分析论文

关键词：桥梁桩基　复合地层　施工振动　测试分析

中图分类号：　文献标识码：A　文章编号：1674-098X(2012)1(c)-0104-02

1　复合地层及桥梁桩基施工振动测试的作用

1.1　复合地层特性

复合地层由两种或两种以上不同地层组成，且这些地层的岩土力学、工程地质和水文地质等特征相差悬殊的地层组合。复合地层的组合形式是非常复杂多样的，但总的来说可分为三种：一种是在断而垂直方向上不同地层的组合；一种是在纵向方向上不同地层的组合；第三种是上述两者交叉出现。最典型的垂直方向上的复合地层就是所谓“上软下硬”地层。及上部是松软的土层，而下部是坚硬的岩石地层。本文的研究主要针对上软下硬方式组合的复合地层。

1.2　桥梁桩基施工振动测试的作用

桥梁桩基冲击钻孔施工往往是一个强迫振动过程，振动波向四周辐射，形成了振动影响场，对邻近建构筑物以及人们的正常工作、生活造成影响。因此，在桥梁桩基施工过程中，应加强对桩基施工振动进行综合、系统的测试，为工程的顺利进行保价护航。对桥梁桩基施工振动测试具有以下几方面的作用：(1)依靠现场测试提供动态信息反馈来指导施工全过程；(2)对周围建构筑物的破坏评估提供可靠的数据；(3)可及时发现和预报险情的发生及发展程度，为及时有效地采取安全补救措施充当耳目。(4)积累数据资料，为类似工程提供参考。

2　复合地层桥梁桩基施工振动特性分析

在桥梁桩基冲击钻孔时，地下某处会产生间隔较短的瞬间激振，地层中各质点因受迫振动而以波动的形式从振源经地层半空间向外传播，在振源区以体波为主，到达一定的距离后而波变成了主导波。在各地层质点受追振动时，土体单元承受蓿正应力应变和剪应力应变，实际体系可视为具有单位截面积高度的土柱所构成的离散体系。假定整个土体质量集中于该层中自上而下的若干离敞点，当土体中某一单元激振时产生能量不同的振动，其地下振动的工程特性常以振动振幅、频谱和持时来表示，它与地层结构、振源机制及介质的动力特性有关。当振动超过某一限制时，地层土体所受的瞬间地振动荷载超过其本身的极限值，而使地基基础失稳，从而危及周围建构物的安全，甚至直接危及生命和财产安全，因此，必须对桥梁桩基复合地层中施工产生的振动进行强有力的测试。

3　工程实例分析

3.1　工程概况及地质条件

本文振动试验选择在地处复合地层的某高速公路一座主线桥进行。该桥梁基础设计为钻孔灌注桩基础；设计桩长24m，桩直径1.8m，采用CZ60冲击钻钻孔施工。CZ60冲击钻钻机，锤重5.3吨，震动影响半径为7m。

该桥址场区属河床阶地区，地形略有起伏，河床堆积亚砂土，卵石土、漂石土，厚度9～24.5m。下伏燕山期花岗岩，节理裂隙较发育，岩石较完整，场区内无不良地质现象。其地质情况如表1所示。

3.2　测试方案及测点布置

本次试验采用的仪器为中科院成都中科测控公司生产的TC-4850型测振仪和与之相配套的传感器，并经过我国计量部门标定验证。

根据现场情况，在离桩基同一水平位置布置6个传感器，测试竖直方向的振动速度。布置时，将地表的浮土清除，形成一个体积约为0.05m(深)×0.1m×0.1m的正方体形土坑，然后打入约80cm的钢筋，再灌注水泥使之结合牢固，最后用石膏布置好传感器。测点实际现场布置如图I所示，振动测点布置示意图如图2所示。

图2中坐标原点为桩基中心，测点沿桩基同一水平布置，沿x正向测点编号为1，2，3，4，5，6，测点间距离为2m。

3.3　测试结果分析

(1)地层结构对地面质点振动速度影响分析

影响桥梁桩基冲击钻孔振动的因素很多，诸如冲击锤提升高度，桩基掘进深度，地面环境，地层结构等。本文主要分析对振动速度产生影响的两个关键因素，即地层结构、冲击锤提升高度。在试验中，对桥梁桩基不同深度处岩渣进行了取样。如下图3，图4所示。

结合该桥梁场区地质结构情况以及对岩土试样进行分析可知，桥梁桩基掘进深度为8.5m时听处地层为卵石土地层，厚度约5.3～7.9m；14.0m时为强风化花岗岩地层，厚度约1.3～5.7m；17.7m时为弱风化花岗岩地层，厚度约5.6～7.0m；22.5m时为微风化花岗岩地层，厚度约3.1～6.8m。

在上述四种不同地层中进行振动试验时，桩基冲击钻孔施工参数控制如下：冲击锤提升高度约0.5m，冲击钻锤击频率约15～20次／min。测得各测点振动速度随桩基掘进深度变化曲线如图5所示，测点1实测波形如图6、图7，图8，图9所示。

从图5可以看出，桩基掘进深度不同，即桩基所处的地层不同时，地面质点振动速度由近及远的衰减规律相似，都是在10m范围之内衰减较快，10m之外衰减相对较慢，但在卵石土、强风化花岗岩地层中整个振动速度均比在弱风化花岗岩、微风化花岗岩地层中衰减快。当桩基从强风化花岗岩地层(H=14.0m)掘进到弱风化花岗岩地层(H=17.7m)中时。测点的振动速度出现了明显波动，产生了较大衰减。

(2)冲击能量对地面质点振动影响分析

通过在四种不同地层中冲击施工时，改变冲击锤提升高度来获得不同的冲击能量，分析冲击能量的变化对测点振动速度的影响。由于在四种地层中，不同冲击能量施工时，测点振动速度变化规律均相似，本文选择在强风化花岗岩地层中即桩基掘进深度14.0m时进行試验，分析不同冲击能量下，测点振动速度变化规律，在试验中每组试验分别测试了5-8组数据，取其平均值，得到各测点振动速度如表2所示，振动速度随冲击锤提升高度变化曲线如图10所示。

从上图可以看出，冲击锤提升高度不同，即冲击能量不同时，同一测点振动速度随冲击能量的增加而增加，整个衰减规律相似，在近距离范围内测点的振动速度衰减较快，到10m左右，振动速度衰减变缓。

4　结语

篇5：振动测试的教学实验设计分析论文

I. 第一部分 听力（30分）

第一节 听下面5段对话。每段对话读一遍

1. How much did the man pay in fact?

A $47 B.$49 C.$51

2. What made the man tired?

A. He played football last night

B .He took a lot of pictures last night.

C .He didn’t sleep until midnight.

3．Which country is the woman going to visit with her family?

A. Spain B .Greece C. France

4. What is the man’s attitude towards stopping smoking?

A .He is joking. B .He is careful. C. He is serious

5. What does the woman mean?

A. She’d like to lend her bicycle to the man.

B. She doesn’t have a bicycle.

C .She doesn’t want to lend her bicycle to the man.

第二节 听下面5段对话或独白 。每段对话或独白读两遍

听第6段材料，回答第6－8题

6 .What did Dick think of the English and math papers?

A. The questions were very easy.

B .The questions were quite difficult.

C. He thought he may fail the exam.

7. What did Dick think of the Intelligence Test(智力测试)?

A. He thought he failed it. B. He thought he passed it. C. He thought it’s very easy.

8. What did Mary think of the English and math papers?

A. The questions were very easy. B .The questions were difficult. C. She didn’t know it.

听第7段材料，回答第9－11题

9．What kind of man is described by the man speaker?

A. A teenager B. A young man C.A very old man

10. What color are the man’s eyes ?

A. black B. blue C. brown

11. What is the man wearing?

A. a big white sweater, white shorts and an open-necked shirt。

B. a big black sweater, white shorts and an open-necked shirt.

C. a big white sweater, black shorts and an orange shirt.

听第8段材料，回答第12－14 题

12. What is the probable relationship between the two speakers?

A. mother and son B .teacher and student C .boss and secretary

13. Why does the woman want to talk with the man?

A. Because the man failed in the exam.

B .Because the woman is a serious person.

C .Because the man often misses class.

14. How many courses does the man feel very boring?

A. Two B .Six C .Eight

听第9段材料，回答第15－17 题

15．What do you know about the man’s neighbor?

A .He’s sleeping B. He is leaving soon C. He’s making noise

16. What were the man and his friends about to do?

A. End their activity.

B. Leave where they were.

C. Apologize to their neighbor.

17. Where does the conversation take place?

A. At a hotel B. In a flat building C. In the manager’s office

听第10段材料，回答第18－20 题

18. Which sentence best describe the accident?

A. The accident was a result of drunken driving

B .Poor weather conditions led to the accident.

C. A moving truck hit a stopped school bus.

19. About what time did the accident happen?

A .Shortly before 3 p.m

B. Shortly after 3 p.m

C. Shortly before 5 p.m

20.How many traffic accidents have happened in the city this month

so far as we know?

A. 3 B. 5 C.7

II. 单项选择 (15分)

21. ------Is your headache getting______?

------No, it’s worse.

A. better B. bad C. less D. more

22. -----Will you do me a favor?

------With pleasure.________

------Go and ask John to return the money he owes me.

A. I beg your pardon? B. What’s that? C. No problem D. At your service

23.The young man was determined to leave,_________ his parents’ disagreement.

A. by means of B. regardless of C. due to D. in favor of

24. -----My boy, you’d better _______ what you have been treated.

-----Why? I’m almost killed.

A. put down B. put up with C. put up D. put away

25. I’m going to the supermarket this afternoon. Do you have anything _______?

A. to be buying B. to buy C. for buying D. bought

26. ________ the meeting himself gave them a great deal of encouragement.

A. The president will attend B. The president to attend

C. The president attended D. The president’s attending

27. With a lot of difficult problems ________, the newly-elected president is having a hard time.

A. settled B. settling C. to settle D. being settled

28. The wound might ______ if it can’t be treated properly.

A. get infecting B. get infect C. get infected D. get to infect

29. The building project _______ next month is, I think, not easy _______ on time.

A. being carried out; to complete B. carried out; to be completely

C. to be carried out; to complete D. to be carried out; complete

30. Because of his poor English, the boy couldn’t make himself _________.

A. understand B. understood C. understanding D. to understand

31. Alice returned from the manger’s office, _______ me that the boss wanted to see me at once.

A. having told B. tells C. to tell D. telling

32. _________in the queue for half an hour, Tom suddenly realized that he had left his wallet at home.

A. To wait B. Have waited C. Having waited D. To have waited

33. ----There is a story here in the paper about a 110-year-old man.

----My goodness! I can’t imagine_______ that old.

A. being B. to have been C. to be D. having been

34. _________ your essay carefully before you hand in, some mistakes can surely be avoided, I think.

A. Having checked B. As long as you check C. Check D. While checking

35. All the attention of the fans _______ the China’s nationwide youth singing competition these days.

A. has concentrated to B. was paid to C. has been focused on D. was fixed on

III.完形填空（30分）

The child in the hospital bed was just waking up after a throat (喉咙) operation. His throat 36 , and he was afraid. However, the young nurse 37 by his bed smiled so 38 that the little boy smiled back. He 39 to be afraid. The young nurse was May Paxton 40 she was deaf (聋的). May Paxton gratuaded 41 the Missouri School for the Deaf near the year 1909. Three years 42 ，she went to see Dr Richardson about 43 a nurse. Dr Richardson was one of the founders of Mercy Hospital of Kansas City. 44 had never heard of a deaf nurse. She told May that her 45 would be very low and that the work would be 46 . However, May said that did not frighten her. Dr Richardson was 47 her, and accepted May as a student nurse.

Dr Richardson never 48 her decision. 49 , she was so pleased with May’s work that she later accepted two other deaf women as student nurses. The 50 was Miss Marian Finch, who was hard of 51 . The second was Miss Lillie Bessie. These three were 52 “ the silent angels (天使) of Mercy Hospital” during the 53 they worked there.

Dr Richardson often 54 her faith in the girls’ ability to learn nursing. She wrote to May, “For three years, you have been with us--- It is wonderful to me that no man, 55 or child ever, to my knowledge, made a complaint (投诉) against you---”

36. A. damaged B. cut C. hurt D. wounded

37. A. lying B. standing C. crying D. jumping

38.A. cheerfully B. sadly C. shyly D. weakly

39. A. began B. forgot C. continued D. stopped

40. A. but B. so C. for D. and

41. A. as B.in C. with D. from

42. A. ago B. later C. then D. before

43.A. becoming B. hiring C. seeking D. changing

44. A. You B. We C. She D. He

45. A. money B. check C. pay D. price

46. A. easy B. difficult C. joyful D. disappointing

47. A. satisfied with B. ashamed of C. sorry for D. angry with

48. A. liked B. thought of C. regretted D. believed

49. A. In public B. In a hurry C. In surprise D. In fact

50. A. first B. one C. other D. others

51. A. reading B. listening C. hearing D. writing

52. A.told B. called C. chosen D. offered

53. A. year B. month C. term D. time

54. A. spoke of B. said C. heard of D. noticed

55. A. boy B. person C. woman D. girl

IV. 阅读理解（40分）

A

Geena David knew she wanted to be a movie star when she was very young. She was not sure what gave her the idea, but she wanted to look like a movie star. “I have a lot of pictures from my childhood of me wearing sunglasses,” she says. “I used to wear them to watch TV.”

Early movie actors started wearing sunglasses not because they looked good, but because their eyes hurt. The lights used on movie sets were extremely bright and could cause a painful problem known as “Klieg eyes”. It was named after the Klieg brothers who invented the lights. Actors wore sunglasses to give their eyes a rest. But when movie stars began wearing their sunglasses in public, they quickly became a must.

Eventually actors started wearing sunglasses in their movies as well as on the street. Audrey Hephburn wore ultra-cool Ray-Ban sunglasses in the 1961 movie, Breakfast at Tiffany’s. As a result, Ray-Ban sunglasses started to appear more and more in the movies. In 1979, Ray-Ban “Wayfarers” were worn by Jake and Elwood in The Blue Brothers. Tom Cruise wore Ray-Ban “Aviator” sunglasses in the 1986 hit, Top Gun. Then in , Will Smith and Tommy Lee Jones made Ray-Ban “Predator” sunglasses famous in Men in Black.

Of course sunglasses aren’t just a fashion statement. The main reason to wear sunglasses is to protect our eyes against UV radiation. UV radiation can damage our eyes, so people now choose their sunglasses carefully. But you don’t have to give up style for safety. The choice of frames and lenses available these days is huge. So you can protect your eyes and still be the coolest person on the beach..

56. What is mainly discussed in this passage?

A. The use of sunglasses.

B. The history of sunglasses.

C. The sunglasses wearing.

D. Why movie stars like to wear sunglasses.

57. Why did Geena David like to wear sunglasses?

A. She was a movie star.

B. She wanted to follow a movie star.

C. Wearing sunglasses was good to her eyes.

D. It was good to wear sunglasses when watching TV.

58.Early actors’ eyes hurt because ______.

A. they wore sunglasses

B. they went out in the sun too much

C. the lights on movie sets were too bright

D. their scripts were written in very small writing

59. Now people wear sunglasses ______.

A. just to protect their eyes

B. for fashion and to protect their eyes

C. because of bright lights

D. because movie stars wear them

B

It looks like a mobile phone, but the service is much cheaper. It acts like a mobile phone, but only in your own city. Beyond the city walls, it’s useless.

“Little Smart”, also called “xiaolingtong”, has always been compared to mobile phones. But actually, it is more like one of those cordless phones(无绳电话) used around the home. The only difference is that this one reaches much further than from the bathroom to the living room. It can travel across an entire city.

Cheap costs are the main reason for the success of Little Smart. It costs 25 yuan a month for the line and about 0.1 yuan per minute to use. A mobile phone, on the other hand, can cost four or five times as much. What’s more, unlike mobile phones, there’s no fee(费) for incoming calls. So these low charges have attracted many users.

But, Little Smart is not really that smart. Users often complain about its bad voice quality. And there are not as many stations to pick up its signals as there are for mobiles. “I couldn’t receive a phone call if I was on a bus,” said Li Ping, a user in Hangzhou. “It worked fine when I stood still, but there were breaks in signal when I was moving.”

Scientists are trying to make Little Smart more user-friendly. Messaging and Internet access(接入) have been added to the service. And the latest Little Smart handset even has color screen..

60. Why is Little Smart popular in China?

A. It looks like a mobile phone.

B. The service is much cheaper.

C. There is no fee for incoming calls.

D. All of the above.

61. Why are users not satisfied with Little Smart?

A. They can’t hear each other clearly out of the city.

B. There are so few stations for Little Smart to pick up its signals.

C. When you use it, you must stand up.

D. The charges are low.

62. The underlined word “handset” in the last paragraph means “______”.

A. the hand bag B. telephone

C. service D. mobile phone

63. What can we infer from the passage?

A. It’s wrong to say that Little Smart is smart.

B. Scientist are trying to make Little Smart smaller.

C. Little Smart will be better than today.

D. People will change Little Smart into a mobile phone.

C

Shopping for clothes is not the same experience for a man and a woman. A man goes shopping because he needs something. He knows what he wants, and his purpose is to find it and buy it, the price is the less consideration. All men simply walk into a shop and ask the assistant for what they want. If the shop has it, the salesman immediately produces it, and the business of trying it on is done at once. All being well, the bargain can be and often completed in less than five minutes, with hardly any chat and to everyone’s satisfaction.

For a man slight problems may begin when the shop does not have what he wants. Then the salesman tries to sell the customer something else. He usually says,“I know the jacket is not the style. But would you like to try it on? It happens the color what you wanted.”Few men have patience with this treatment, and usually the reply is,“This is the right color and maybe the right size, but I should be wasting my time and yours trying it on.”

Now how does a woman go about buying clothes? She does so in the opposite way. She has never fully made up her mind what she wants and she is only having a look around. She is always open to persuasion, indeed she considers of great importance what the saleswoman tells her, even what her friends tells her. She will try a number of things. Highest in her mind is the thought of finding something that everyone thinks suits her. Most women have excellent sense of value when they buy clothes. They are always trying to find an unexpected bargain. Faced with a roomful dresses, a woman may easily spend an hour going from one counter to another before selecting the dress she wants to try on. It takes a great deal of time but gives great joy. Most dress shop supply chairs for the waiting husbands.

64. When a man is buying clothes, he _______________.

A. puts price before quality

B. chooses things that others think suitable for him.

C. does not mind the price he has to pay for the right things.

D. buys good quality things, so long as they do not cost too much.

65. When a man cannot get what he wants, he ________________________.

A. buy something of the same color in a slightly different style.

B. usually does not buy anything.

C. will try on some other clothes of the same style.

D. waste time in buying something else.

66. What does the passage tell us about women’s shopping for clothes?

A. They welcome suggestion from anyone.

B. Women seldom consider buying cheap cloths.

C. Women often buy things without thinking.

D. They listen to advice but never take it.

67. The most obvious difference between men and women shopper is___________

A. that men do not try clothes on in a shop while women do.

B. that women bargain for their clothes and men don’t.

C. that women do their shopping standing up while men do theirs sitting down.

D. the time they take over buying clothes.

D

The medical world is gradually realizing that the quality of the environment in hospitals may play an important role in helping patients to be better.

As part of a nationwide effort in Britain to bring art out of the museum and into public places, some of the country’s best artists have been called in to change older hospitals and to soften the hard edges of modern buildings. Of the 2,500 national health service hospitals in Britain, almost 100 now have valuable collections of present art in passages, waiting areas and treatment rooms.

These recent movements were first started by one artist, Peter Senior, who set up his studio at a Manchester hospital in northeastern England during the early 1970s.

He felt the artist had lost his place in modern society, and that art should be enjoyed by a wider audience.

A common hospital waiting room might as many as 5,000 visitors each week. What a better place to hold regular exhibitions of art! Senior held the first exhibition of his own paintings in the outpatients waiting area of the Manchester Royal Hospital in 1975, believed to be Britain’s first hospital artist . Senior was so much in demand that he was soon joined by a team of six young art school graduates.

The effect is striking. Now in the passages and waiting rooms the visitors experience a full view of fresh colors ,playful images, restful courtyards.

The quality of the environment may reduce the need for expensive drugs when a patient is recovering from an illness. A study has shown that patient who had a view onto gardens needed half the number of strong painkillers compared with patients who had no view at all or only a brick wall to look at.

68. Some best artists have been called to_______________________.

A. pull down older hospitals and build up new ones.

B. make the corners of the hospital’s building round.

C. bring art into hospitals.

D. help patients recover from illness.

69. Peter Senior is ________________________________.

A. one of the best artists in Britain.

B. A pioneer in introducing art into hospital.

C. One of the young art school graduates.

D. A kind painter who brings only his paintings into hospitals.

70. From this text, we’ve learnt that _____________.

A. artists in Britain have completely lost their places in modern society.

B. patients should be encouraged to learn art

C. hospitals in Britain should be charged into art hospitals

D. art should be encouraged in British museums.

71. After the improvement of the hospital environment ____________

A. patients no longer need drugs to kill their pains.

B. patients needn’t buy any expensive drugs.

C. patients need fewer painkillers when they are getting better after illness.

D. Patients can take fewer pills each time

E

An American study has examined the effects of a low-fat diet on the health of woman. The study has found that such a diet does not reduce the risk of at least one kind of cancer, heart disease or stroke.

For years, medical experts have thought that a diet that is low in fat helps reduce the risk of cancer and heart disease. Researchers with America’s National Institutes of Health created a study to test this theory. It is one of the largest studies ever done on this subject.

The researchers have studied the health of almost50,000 women for eight years. These women were between the ages of 50 and 79. The women in one group reduced the fat in their diet to twenty percent of their total daily food supply. They also increased their daily servings of vegetables, fruits and grains. The other group of women did not make any dietary changes. The researchers compared the two groups.

The result of the study show the different diets have little effect on the health of the women. Both groups had the same rates of heart disease and colorectal cancer（直肠）. The researchers said the women who followed the low-fat diet might have less risk of breast cancer. But the difference was so small that it was not considered important.

Experts say the results are important for both men and women. Some critics of the study fear many people will think that diet is not important. Other studies have shown that a healthful diet is still important, but so are other choices. For example, exercising, avoiding smoking, and keeping a normal body weight are also necessary for good health.

Other experts noted the study called for reducing total fat instead of the kinds of fats that are not healthful. For example, fats in some foods like fish and nuts are considered good for human health. Unhealthful fats include saturated（含饱和脂肪酸的） fats and trans-fats. The study did not note differences between these two kinds of fats. Experts also said that dietary changes might need to begin earlier in life to have a greater effect on disease and cancer prevention. Some researchers suggested the study would have shown better results if the women had eaten even less fat.

72. Studies show that a low-fat diet probably reduces the risk of __________.

A. heart disease B. stroke C. colorectal cancer D. breast cancer

73. The following statements are true about the last paragraph EXCEPT that_______________.

A. the results of the study are also important for men.

B. some experts think that we should reduce total fat including healthful kinds.

C. the studied women should have taken much less fat

D.. change your diet now and you’ll have a quick effect on disease prevention

74.Which of the following is NOT mentioned to keep healthy?

A. Keeping a healthy diet B. Being in a good mood.

C. Avoiding smoking. D. Keeping a normal body weight.

75. What is the conclusion drawn by the study?

A. Keeping a diet is not necessary. B.. Taking more fat if necessary.

C.There are differences between fats. D. Low-fat diets alone do not reduce health risks.

第Ⅱ卷

V. 对话填空题（10）

W: Tom you are learning English in an evening school, 76a _______ you?

M: Yes, English is very important, you know.

W: Didn’t you 77e________learn it when you were a college student?

M: Yes. But I have found my English is too 78l_________ since I 79b________

to work in this company.

W: Don’t you think you are too old to learn it?

M: Oh, no. I’m much 80y__________ compared with Karl Marx ; he began to

learn Russian in his fifties. He 81n__________ stopped learning foreign

languages in his 82l___________.

W: So he knew many foreign languages, didn’t he?

M: Yes. He 83c___________ read all the leading European languages and 84w__________

in three – German, French and English. He was a man of a great

talent 85f____________ language.

VI. 单词拼写 （10）

86. I don’t like her unhelpful a_________.

87. The car crash wasn’t an accident; it was a d________ attempt to kill him.

88. You should a________ to her for stepping on her foot.

89. The discovery e________ his reputation.

90. He was arrested because he has done something i_________.

91. It’s a _________(辩论) about the punishment for criminals.

92. She was in a __________(进退两难) as to whether to stay at school or get a job.

93. This country is wasting its _________(资源) on building old-fashioned ships.

94. He is a _________(固执的) child who won’t obey his mother.

95.The government has promised to take __________(措施) to help the unemployed.

VII. 书面表达（15）

近日，你班在“知荣明耻”教育活动，召开了一次关于学生荣辱观的主题班会。请你根据下表中的内容，用英语写一篇短文，给校报“八荣八耻大家谈”栏目投稿。

存在的问题 1．不尊敬老师、家长等；

2．学习散漫，考试作弊等；

3．乱仍垃圾，污损环境等；

对荣辱观的认识 1．以遵纪守法关心集体、勤奋学习等为荣

2．以违反校规、自私自利、不思进取等为耻

将认识落实在行动中的打算 …………

注意：

1． 词数：120左右。短文的开头已为你写好，不计入总字数。

2． 内容可适当发挥，注意行文连贯。

Recently we have had a class meeting to discuss what is considered to be honorable behavior and what is shameful. ________________________________________________________________

_______________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________ _

________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________

全部答案：

听力答案：

1---5 CCBAB

6---10 AABBB

11---15 ABCAB

16---20 AACBC

单选答案：

21-25 ABBBB 26-30 DCCCB 31-35 DCABC

完形填空：

36-40 CBABD 41-45 DBACC 46-50 BACDA 51-55 CBDAC

阅读理解：

56-59 CBCB

60-63 DBBC

64---67 CBAD

68---71 CBDC

72-75 DDBD

对话填空：

76.aren’t 77.ever 78.limited 79.began 80.younger

81.never 82.life 83.could 84.write 85.for

单词拼写：

86．attitude 87.deliberate 88.apologize 89. established 90. illegal

91. debate 92. dilemma, 93.resources, 94.stubborn, 95. measures

One possible version:

To be frank, some students don’t respect their teachers or parents, and some don’t take their studies seriously and cheat in exams. Even there are some students who litter around, making the school dirty.

It is really a pity to see these things in our school. We think it honorable to obey the rules and regulations of school and care much about our class . It is also worthy of praise for studying hard. On the other hand, it is shameful to break school rules, to be selfish or to make little effort to achieve success.

篇6：大气压强的创新实验设计分析论文

分析了大学生宿舍空间以及微收纳家具的概念和发展现状，探讨了大学生宿舍和微收纳家具之间的关系，研究了大学生宿舍微收纳家具的设计功能要求、表现形式及理念。指出，微收纳家具营造宿舍空间带来的空间的灵活性，解决了大学生宿舍中空间不足的问题，为大学生提供更大的生活空间。

关键词：大学生宿舍；空间；微收纳家具；设计研究验证

大气压的存在是“大气的压强”一节教学的重要内容，这对帮助学生认识大气压的相关知识有不可缺或的作用．虽然大气压与我们的生活密切相关，但由于空气不像固体和液体那样可以直接视觉或有直接的触觉感受，大气压的存在又不为我们所觉察，这对于刚接触物理的学生来说，认识大气压有一定的难度或疑惑，必须有足够实验和事例来演示说明．因此在“大气的压强”的教学中，通过演示实验和自主性学习体验到大气压强的存在是这节课的重点，也是引导学生体会到大气压强存在的关键．而教材中的演示实验是有限的，能够演示大气压强的实验也不少，但是有些演示实验不是实验过程复杂、效果差，就是成本高，或者费时等等，如马德堡半球模拟演示实验，将两个半球对在一起，然后用抽气机将中间的空气抽出，这就需要较长的时间;由于仪器老化，半球的密封性变差，使得球内的空气也不易抽尽，导致学生在拉球时不用费很大的力就把半球拉开，不能反映大气压有很大压力的物理事实．因此，需要物理教师挖掘实验资源，引导学生到生活中去找原型，用创新的教学手段，展示生动、有趣、明了、简洁的气压应用实例，以加强学生运用所学知识解决实际问题的能力，培养他们的观察能力、动手能力及创新思维．下面介绍几例大气压强的创新实验．

1敞口气球

你看到过气球吹大后，敞着口不变小的情景吗?许多学生不相信是真的，当看到真实情景时，又百思不得其解．实验器材大的饮料瓶(如5升雪碧瓶)、气球等．首先对饮料瓶作一个简单的处理(其处理方法不说同行们一定能从下面的介绍中明白)，然后在气球未吹之前，把气球的顶部向饮料瓶的瓶口灌进去，使气球的大部分进入饮料瓶，再把气球的口反套到饮料瓶的瓶口上．用手握住饮料瓶，现在用嘴对着饮料瓶的瓶口吹气，等气球吹大后，停止吹气．一个气球敞着口不变小的气球就出现在你的面前．学生看了非常好奇，气球吹起来后，必须把气球的口扎紧，气球才能在较长一段时间内不明显变小．现在气球敞着口为什么不变小呢?原来这里巧妙的借助饮料瓶和大气压共同发挥作用，才出现奇特的现象．而学生看到这个演示现象既疑惑又兴奋，这是一个既有知识性，又有趣味性、娱乐性的演示实验，容易形成学生的激情和师生互动，由此产生的课堂教学效果，不言而喻．更令学生疑惑的是，学生并没有发现老师有其他的操作动作，但是，当老师说气球变小，气球真的逐渐变小;当老师说气球停止变小，气球果然停止变小，敞着口保持一定形状鼓着．气球能够膨胀，必须克服橡胶皮的束缚力．因此，吹气就比较吃力．同样，吹大的气球，敞着口不变小，也必须克服橡胶皮的束缚力．靠什么来克服橡胶皮的束缚力，从实验中发现，只有靠负压来实现．怎样产生这么大的负压呢?你应该发现其中的奥秘了吧．不要把这个实验的奥秘直接告诉学生，而是引导他们探究，这有利于调动学生的积极性和创新思维．这个演示实验对讲授高一理想气体变化规律知识点也有一定辅助说明作用．吹大的气球敞着口不变小，其实质是一个平衡问题．密闭在气球与饮料瓶之间的气体遵守玻意尔马略特定律:在密闭容器中的定量气体，在恒温下，气体的压强和体积成反比关系．用玻意尔马略特定律就能轻松的解释，敞着口的气球为何不变小．因为气球虽然敞着口鼓着，但是气球内腔的气体是恒定的一个大气压保持不变，假设气球缩小，那么根据玻意尔马略特定律，密闭在气球与饮料瓶之间的气体体积就要变大，而温度几乎是不变的，则气球外围的气压就会变小，因此气球内、外的气压差就会阻止气球变小，所以在这种情形敞着口的气球不会变小，除非使气球与饮料瓶之间的气体与外界连通．这样把初中物理向高中物理适当延伸，有利于满足不同层次学生的发展需求．

2飞球吸壁

许多玩具是根据物理原理设计生产的，能呈现物理现象和显现物理规律，其巧妙的设计使外观很精美、色彩很鲜艳，呈现的现象非常神奇，对学生很有吸引力，把玩具功能扩展为教学功能，使学生在好奇中学习物理知识．例如，用吸壁球演示大气压的作用．实验器材吸壁球(玩具市场可以买到)．吸壁球的彩色很有吸引力，因为这种球的表面非常特殊，由多种不同颜色的塑料小吸盘组成，塑料小吸盘的弹性非常好．实验方法在讲授大气压强和摩擦力知识点时，用吸壁球做演示实验，对学生也很有吸引力．有些学生可能没有看过这个玩具，先把它向学生展示一下它的外貌，学生对它比较陌生，更不知道是做什么用的．突然把它向黑板抛去，它稳稳地吸在黑板上(如图1所示);再向窗户的玻璃上抛去，它就稳稳地吸在玻璃上，向天花板抛去，它就吸在天花板上．只要是光滑的平面，可以用力直接推上去，也可以向平面抛去(稍有点撞击速度即可)，都能吸在竖直的平面上，吸在竖直平面上的时间跟撞击速度和平面的光滑程度有关．在其他条件相同的情况下，撞击速度较大，吸在平面上的时间较长．这个演示实验学生都能积极参与，便于探究、体验．然后引导学生一起分析实验现象的原理，学生对大气压强知识的消化也就不难了．让学生在“玩”中学，教师指导得轻松，学生学得也轻松．实验现象剖析:当用力把吸壁球抛到竖直的平面上时，由于撞击力的作用，使其中的一个塑料小吸盘内的空气挤出了一部分，塑料小吸盘在恢复形变的弹力作用下，试图恢复原状而使空腔欲变大，这样塑料小吸盘内的气压就要减小为p1，而它的外部大气压p0不变(如图2所示)，内外气压差使塑料小∥盘受到垂直于竖直平面的压力F=(p0－p1)S．设吸壁球与竖直平面的静摩擦因数为μ，那么吸壁球与竖直平面之间的最大静摩擦力为FM=μF=μ(p0－p1)S．刚开始时FM=G(G为吸壁球所受的重力)，由于吸壁球与竖直平面之间总是存在缝隙，外面的空气会不断地通过缝隙进入到塑料小吸盘内，使小吸盘内的气压p1不断变大，随着p1的增大，最大静摩擦力FM逐渐减小，最终当FM接近G时，吸壁球掉落下来．

3一张报纸的力量