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BEPCⅡ高频屏蔽波纹管纵向耦合阻抗测量和数值计算 总被引:1,自引:0,他引:1
根据BEPCⅡ工程的需要, 在高能物理研究所搭建了阻抗测量平台, 对BEPCⅡ部分真空部件进行纵向耦合阻抗的测量. 测量平台基于同轴线方法, 使HP/Agilent 8720ES微波网络分析仪在频域进行测量. 在此平台上可以用TRL校准技术和等长比较件两种方法测量真空部件耦合阻抗. 本文介绍BEPCⅡ阻抗测量平台以及对高频屏蔽波纹管(bellows)的阻抗测量和数值计算结果, 并对测量结果和测量平台系统误差进行了分析. 相似文献
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本文介绍一种用脉冲法测量超声波传播时间的装置.该装置使用灵活方便,可用反射、透射、液浸等方法测量.其中用两次回波测量,可自然补偿掉延时,无须修正.它不用手动调节临界点,故最适于需实时快速测量的场合.如有需要,它可与计算机联接进行实时数据处理并打印出测量结果.本装置由普通设备组成,价格不昂贵,而测量精度能满足通常要求.与适当结构的换能器配合,可测量固体、液体或生物软组织的声速、厚度及其变化.也能用于测量声衰减或探伤.本文用实例说明了测量方法. 相似文献
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为测量GNSS天线连接器同轴度误差,构建了连接器分段旋转数学模型,提出了一种水平转台和机器视觉结合的非接触式测量方法,搭建测量装置并进行了测量实验.分析连接器运动方式和同轴度误差测量方法,确定各轴线之间的偏移关系,建立同轴度误差数学模型和测量模型.搭建测量装置,相机安装在水平转台上方,光轴平行于水平转台轴线.旋转水平转台,使用相机捕捉转接螺杆端面圆心位置并拟合轨迹,完成测量装置同轴度误差自标定.将连接器安置在水平转台上,旋转水平转台,测量连接器顶部螺纹杆轴线相对水平转台轴线的偏移.旋转连接器的承载器,测量连接器顶部螺纹杆轴线相对承载器轴线的偏移.最终,综合各轴线的偏移关系得到连接器同轴度误差的最大值.实验结果表明,测量装置对GNSS天线连接器同轴度误差的测量标准差为9μm,单次测量结果的扩展不确定度U=30μm(k=2),满足GNSS天线连接器0.1 mm至1 mm量级的同轴度误差的测量需求,使用连接器同轴度误差修正GNSS超短基线测量结果,可以显著提升基线测量精度. 相似文献
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根据表面波声光效应的原理,实验上建立了固体表面微振动的激光衍射测量系统.当激光斜入射到微振动引起的液体表面波上,观察到了清晰、反衬度非常高的衍射图样.利用MATLAB软件对拍摄的衍射图样进行扫描,得到了衍射光斑的光强分布图,并根据衍射图样宽度与表面波振幅的解析关系式,求出了液体表面波的振幅,其大小在微米量级.改变样品池中液体的深度,测得不同深度下液体表面波的振幅,给出了表面波振幅与液体深度之间的解析关系,并发现了液体对微振动的放大效应.利用液体对微振动的放大效应,求出了固体表面微振动的振幅,实现了固体表面微振动的探测. 相似文献
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根据表面波声光效应的原理,实验上建立了固体表面微振动的激光衍射测量系统.当激光斜入射到微振动引起的液体表面波上,观察到了清晰、反衬度非常高的衍射图样.利用MATLAB软件对拍摄的衍射图样进行扫描,得到了衍射光斑的光强分布图,并根据衍射图样宽度与表面波振幅的解析关系式,求出了液体表面波的振幅,其大小在微米量级.改变样品池中液体的深度,测得不同深度下液体表面波的振幅,给出了表面波振幅与液体深度之间的解析关系,并发现了液体对微振动的放大效应.利用液体对微振动的放大效应,求出了固体表面微振动的振幅,实现了固体表面微振动的探测. 相似文献
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为了研究真空低温环境下定标光学系统光谱反射率测量技术,搭建了小型离轴抛物面反射镜的光谱反射率原位测量试验系统。系统由太阳模拟器、准直镜、折叠镜、离轴抛物面反射镜、光谱仪、数采系统等组成。分别在常温常压和真空低温环境下进行测量,得到350 nm~950 nm谱段光谱反射率及变化规律,常温常压、真空低温、恢复常温常压下系统测量平均值分别为0.882、0.863和0.883,测量重复性1.1%,不确定度优于2.4%。结果表明,反射镜光谱反射率在真空低温环境下有较明显的下降,环境恢复后,反射率随之恢复。 相似文献
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In this study, the conventional plan was compared with the plan that was based on a dose dynamic multi-leaf collimator (MLC), and a dose dynamic MLC was used to evaluate its usefulness. Then, this study examined if it was possible to perform a high-dose radiation therapy by adjusting the dose limit of the spinal cord when the dose dynamic MLC-based plan was used. First of all, linear accelerator was used to compare the conventional plan with the dose dynamic MLC-based plan. Then, the study was conducted in two methods in order to examine the proper range of the shield for the spinal cord when the dose dynamic MLC was used to adjust the dose of the spinal cord. In the first method, X-omat film was used to perform film dosimetry. In the second method, radiation treatment planning (RTP) system was used to find out the proper range among 0, 3, 6, and 9 mm. When film scan was performed in the each range, respectively, from the spinal cord and under the same conditions, it was confirmed to be appropriate to use the range of 3 mm. When the RTP system was used to perform planning in the shield range of each range, respectively, from the spinal cord, dose-volume histogram (DVH) was a slight difference could be found in the region from 25% to 35%. On the contrary, no radiation exposure was found in the region of 35% or higher for all of the each range. Consequently, if MLC is selected in consideration of the planning target volume (PTV), the most proper value can be obtained by selecting the range of 3 mm. Next, the DVH was compared to examine the relationship in PTV when the each range was used for planning. All of the ranges showed the same pattern up to the point of 90%. However, the results were different in the region of higher than 90% because the dose was low for the spinal cord, and a relatively useful dose was used for PTV when the range was 3 mm. 相似文献
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Giovanna Cantarella 《Journal of voice》1988,1(4):353-358
In the past 3 years flexible laryngoscopy was used in the evaluation of 315 patients, ranging in age from 4 months to 86 years (in 136 cases a videorecording was obtained). The technique was especially helpful in cases in which a prolonged visual evaluation of laryngeal motion was required for diagnostic, prognostic, and documentative purposes. The main limitations were lack of image definition and wide angle image distortion. Therefore, accurate evaluation of initial mucosal changes was not possible in some of the cases examined. A stroboscopic light source was used every time the characteristics of the vibratory cycle of the vocal folds had to be studied. This technique was applied mainly to the study of vocal fold vibrations in unilateral laryngeal paralysis. 相似文献
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针对压印过程中两类基本的复型缺陷,从实验分析中得出其主要原因是曝光后阻蚀胶的固化程度难以控制.通过分析紫外曝光光源与阻蚀胶的光谱匹配性,得出使得阻蚀胶固化的有效波长为365nm;对光诱导紫外曝光过程中紫外光的传播分析,建立了阻蚀胶中光强分布的数学模型;用粘度来表征阻蚀胶的固化程度,建立了阻蚀胶中的粘度分布函数.分析了阻蚀胶对365nm紫外光的吸收率以及膜厚对阻蚀胶中光强分布均匀性的影响,得出复型后阻蚀胶凸起处的光强分布均匀性对吸收率及膜厚更为敏感的结论. 相似文献
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《Composite Interfaces》2013,20(5-7):663-675
The thermal behaviour, fire resistance and mechanical properties of jute-reinforced composites with vinylester and resol matrix were studied. Organically modified clay was added to the polymeric matrix in order to enhance the properties of the composites. An inhomogeneous distribution of the nanoreinforcement in the polymer was observed by X-ray diffraction. Thermogravimetric analyses revealed that the addition of clay to the resol resin by sonication enhanced the thermal resistance of the jute-reinforced composite at temperatures higher than 300°C. The fire resistance of the composites was evaluated by means of a cone calorimeter. A diminution in the peak of the heat release rate was observed when clay was added to the polymeric matrix. On the other hand, neither the time to ignition nor the total heat evolved was significantly reduced by the clay addition. Additionally, an increment in the flexural modulus as well as in the flexural strength of the resol composites was observed when the clay was added to the matrix. The fiber–matrix interface of the composites was studied by scanning electron microscopy. It was observed that as the clay dispersion degree was increased the interface quality was diminished in the resol composites. 相似文献