High‐accuracy differential measurement of ultrasonic velocity in liquids

1979 ◽  
Vol 50 (10) ◽  
pp. 1299-1302 ◽  
Author(s):  
John G. Elias ◽  
Don Eden
Keyword(s):  
Ultrasonic Velocity ◽  
High Accuracy ◽  
Differential Measurement

scholarly journals A Differential Measurement System for Surface Topography Based on a Modular Design

2020 ◽  
Vol 10 (4) ◽  
pp. 1536
Author(s):  
Fang Cheng ◽  
Jingwu Zou ◽  
Hang Su ◽  
Yin Wang ◽  
Qing Yu
Keyword(s):  
Surface Topography ◽  
Measurement System ◽  
Modular Design ◽  
Measurement Range ◽  
High Accuracy ◽  
The Novel ◽  
Large Area ◽  
Differential Measurement ◽  
Motion Error ◽  
Novel Concept

In this paper, a novel design of a surface topography measurement system is proposed, to address the challenge of accurate measurement in a relatively large area. This system was able to achieve nanometer-scale accuracy in a measurement range of 100 mm × 100 mm. The high accuracy in a relatively large area was achieved by implementing two concepts: (1) A static coordinate system was configured to minimize the Abbe errors. (2) A differential measurement configuration was developed by setting up a confocal sensor and a film interferometry module to separate the motion error. In order to accommodate the differential measurement probes from both sides of the central stage and ensure the system rigidity with balanced supports, separate linear guides were introduced in this system. Therefore, the motion Degree of Freedom (DoF) was analyzed in order to address the challenge of an over-constrained mechanism due to multiple kinematic pairs. An optimal configuration and a quick assembly process were proposed accordingly. The experimental results presented in this paper showed that the proposed modular measurement system was able to achieve 10 nm accuracy in measuring the surface roughness and 100 nm accuracy in measuring the step height in the range of 100 mm × 100 mm. In summary, the novel concept of this study is the build of a high-accuracy system with conventional mechanical components.

scholarly journals Creation of Pulse Method for Measurement of Ultrasonic Velocity with High Accuracy

2021 ◽  
Vol 19 (2) ◽  
pp. 13
Author(s):  
V V Muravyov ◽  
D V Zlobin ◽  
T I Zemskov ◽  
G V Bezruchenkov ◽  
V V Syaktereva
Keyword(s):  
Ultrasonic Velocity ◽  
Pulse Method ◽  
High Accuracy

В статье обсуждаются способы высокоточного определения скорости ультразвука в твердых материалах. Описана методика проведения точных измерений временных интервалов ультразвуковых импульсов, приведена блок-схема экспериментальной установки. Установка построена на широкодоступных компонентах, возможна ее простая модернизация. Предложено использование датчика на основе сегнетоэлектрического полимера поливинилиденфторида в качестве источника излучения и приема продольных волн. В качестве объектов контроля используются концевые меры длины и ступенчатый образец из стали, изготовленный с использованием плоскошлифовального станка. Представлены результаты определения скорости, подтвержденные многократными измерениями на ступенчатом объекте с разницей по толщине ступеней 10 мкм. Проведен эксперимент при изменяемой температуре образцов концевых мер длины, подтверждающий точность измерений и разницу в рассчитанной скорости, свидетельствующий о разном структурном составе объектов. Определен химический состав образцов концевых мер длины с использованием рентгено-флуоресцентного анализатора. Представлен график зависимости плотности объектов от скорости ультразвука. Описаны погрешности измерений, способы их расчета, в частности временная задержка при использовании пленочного датчика. Абсолютная погрешность определения скорости ультразвуковых продольных волн не превышает 2 м/с, что позволяет фиксировать крайне малые отклонения скорости ультразвука в образцах.

A New 1,000 kV Electron Microscope

1967 ◽  
Vol 25 ◽  
pp. 260-261
Author(s):  
M. Nishigaki ◽  
S. Katagiri ◽  
H. Kimura ◽  
B. Tadano
Keyword(s):  
Electron Microscope ◽  
High Voltage ◽  
Basic Research ◽  
Chromatic Aberration ◽  
High Accuracy ◽  
Biological Specimen ◽  
Voltage Electron ◽  
High Voltage Electron Microscope ◽  
High Voltage Electron

The high voltage electron microscope has many advantageous features in comparison with the ordinary electron microscope. They are a higher penetrating efficiency of the electron, low chromatic aberration, high accuracy of the selected area diffraction and so on. Thus, the high voltage electron microscope becomes an indispensable instrument for the metallurgical, polymer and biological specimen studies. The application of the instrument involves today not only basic research but routine survey in the various fields. Particularly for the latter purpose, the performance, maintenance and reliability of the microscope should be same as those of commercial ones. The authors completed a 500 kV electron microscope in 1964 and a 1,000 kV one in 1966 taking these points into consideration. The construction of our 1,000 kV electron microscope is described below.

Application Of BIM-Technology In The Restoration Of Buildings

2020 ◽  
pp. 42-48
Keyword(s):  
Chinese Communist Party ◽  
Laser Scanning ◽  
High Accuracy ◽  
Information Environment ◽  
Information Modeling ◽  
Structural Scheme ◽  
Traditional Design ◽  
Information Interaction ◽  
Heritage Buildings ◽  
Effective Organization

The paper describes the main trends in the development of BIM technologies in the field of restoration and reconstruction of historical and cultural heritage buildings. The practical part of the paper presents the experience in using information modeling technologies when restoring the building, where the VI Congress of the Chinese Communist Party in Moscow took place. The use of laser scanning technologies made it possible to reproduce with high accuracy in the information model the original appearance of the building using Autodesk RevitR software. It is shown, how the use of information modeling technologies affects the duration of restoration process, taking into account the calculation of the structural scheme and bearing structures of the building, ensuring the identity of the decoration and the effective organization of electromechanical installation. Operating in a single BIM information environment makes it possible to continuously obtain reliable information on the project, which provides more effective information interaction and communication of participants compared to using traditional design methods.

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