scholarly journals A Real-Time Measurement Method of Air Refractive Index Based on Special Material Etalon

2018 ◽  
Vol 8 (11) ◽  
pp. 2325 ◽  
Author(s):  
Guo-Ying Ren ◽  
Xing-Hua Qu ◽  
Shuang Ding
Keyword(s):  
Refractive Index ◽  
Real Time ◽  
Direct Measurement ◽  
Measurement Method ◽  
Measurement Accuracy ◽  
Laser Interferometry ◽  
Measurement Technology ◽  
Measurement Principle ◽  
Environmental Responses ◽  
Realization Process

In the precise displacement measurement based on laser interferometry, the measurement technology for the refractive index of air is widely used to improve the measurement accuracy. However, the existing measurement method of the refractive index of air based on direct measurement is not easy to realize in practical work because of its complex measurement principle and the huge volume of the measurement device; while the measurement accuracy and speed based on the indirect method cannot adapt to the real-time, fast and accurate measurement requirements of industrially changing environments, resulting in distortion of the results. In this study, a measurement method of the refractive index of air based on a special material etalon is proposed. The method enables rapid and direct measurement of the air refractive index when the environment changes and it is given the realization process. Finally, the experimental results show that the deviation between this method and the modified Edlen formula is about 2.5 × 10−7, and that this method can quickly reflect the changes of the environment, which prove the correctness of this method and its ability manage rapid environmental responses. This method is worth popularizing in industrial measurement.

Laser Diode Self-Mixing Interference Based on Phase Measurement Method

2008 ◽  
Vol 381-382 ◽  
pp. 247-250
Author(s):  
Ming Wang ◽  
Dong Mei Guo
Keyword(s):  
Laser Diode ◽  
Phase Modulation ◽  
Signal Analysis ◽  
Measurement Method ◽  
Measurement Accuracy ◽  
Phase Measurement ◽  
External Cavity ◽  
Experimental System ◽  
Measurement Results ◽  
Measurement Principle

In order to improve the displacement measurement accuracy of the laser diode self-mixing interference (SMI), phase measurement method is introduced in the SMI signal analysis. In this paper, three modulation technique have been proposed: injection current modulation, external cavity length modulation and sinusoidal phase modulation. Measurement principle of the three modulation techinque are briefly explained. Design of the experimental system, measurement results of micro-displacement will be reported.

REAL-TIME MEASUREMENT OF ICE CONCENTRATIONS IN ICE SLURRY FLOW

2010 ◽  
Vol 18 (02) ◽  
pp. 157-164
Author(s):  
JONG HYEON PECK ◽  
HIKI HONG ◽  
CHAEDONG KANG
Keyword(s):  
Refractive Index ◽  
Real Time ◽  
Measurement Method ◽  
Density Measurement ◽  
Good Resolution ◽  
Ice Slurry ◽  
Refractive Index Measurement ◽  
The Real ◽  
Error Range ◽  
Index Measurement

An experimental study was performed to measure the ice concentration of an ice slurry pipe flow in real time. In the present work, we suggest a refractive index measurement method and compare it to freezing point and density measurement methods. To measure the refractive index of the solution, ice particles in the ice slurry should be completely removed and a hydro-cyclone was used in this study instead of a mesh. The results from the measurement method by the refractive index coincided with those by the density within a ±5% error range when the real-time solution density was used. Even though the density measurement method showed good resolution, the results using the initial density of the solution were more than 10% in error compared to those using the real-time density. And the density measurement method has an error range 1.5 times greater than the refractive index measurement method.

Research on Aero-Engine Lubricating Real-Time Oil Measurement Method

2014 ◽  
Vol 644-650 ◽  
pp. 840-844
Author(s):  
Bao Feng Shan ◽  
Fan Chen Mo ◽  
Jing Chun Li ◽  
Zhi Ping Tian
Keyword(s):  
Real Time ◽  
Measurement System ◽  
Measurement Method ◽  
Spatial Databases ◽  
Rapid Development ◽  
Time Measurement ◽  
Lubricating Oil ◽  
Measurement Technology ◽  
Real Time Measurement ◽  
Aero Engine

With the rapid development of aviation technology, the performance of aero-engine continues to increase in China. However, Chinese Aero-engine lubricating oil real-time measurement technology is not mature, active airplane almost have no Aero-engine lubricating oil real-time measurement system, It requires further in-depth study.By research on Aero-engine lubricating oil measurement technology. First, it outlined the method and principles of measurement, and based on UG Open the analysis of Aero-engine lubricating oil system was developed. Through which an analysis of the model of Aero-engine lubricating oil, the spatial databases about sensor depth of immersion oil, aircraft attitude and fuel volume were built.,which can provide the data for the subsequent lubricating real-time oil measuring analysis .

Research of Non-Contact Stiffness Measurement Technology

2014 ◽  
Vol 621 ◽  
pp. 331-336
Author(s):  
Wen Xuan Liu ◽  
Hui Feng Wang ◽  
Guang Lin Wang ◽  
Dong Xiang Shao
Keyword(s):  
Measurement System ◽  
Elastic Element ◽  
Measurement Method ◽  
Measurement Accuracy ◽  
Contact Stiffness ◽  
Test System ◽  
Measurement Technology ◽  
Servo Valve ◽  
Stiffness Measurement ◽  
Definition Of

This article describes the elastic element of the servo valve, elaborates the definition of the stiffness of elastic element, analyzes the characteristics of existing rigidity measurement system, points out the limitations of the existing rigidity measurement system when it measures the large-stiffiness elastic element, utilizes a new measuring principle based on the existing stiffness test systems, uses the more accurate laser displacement measurement method to overcome the weaknesses of the existing stiffness test system, improves the measurement accuracy, makes stiffness measurements more accurate and promotes the stiffness measurement technology of the servo valve elastic element.

scholarly journals High-Resolution Multi-Channel Frequency Standard Comparator Using Digital Frequency Measurement

Sensors ◽  
2021 ◽  
Vol 21 (16) ◽  
pp. 5626
Author(s):  
Bo Xiao ◽  
Ya Liu ◽  
Xiaohui Li ◽  
Zhifeng Deng ◽  
Yanrong Xue
Keyword(s):  
Measurement Method ◽  
Measurement Accuracy ◽  
Frequency Standard ◽  
Frequency Measurement ◽  
Low Noise ◽  
Measurement Technology ◽  
Zero Crossing ◽  
Noise Floor ◽  
Digital Frequency ◽  
Atomic Frequency

The rapid improvement accuracy of the atomic frequency standard puts forward higher requirements for the measurement resolution of the atomic frequency standard comparison system. To overcome the defect that the single zero-crossing point detection is sensitive to noise in the traditional dual mixer time difference measurement method, a digital frequency measurement method is proposed. This method combines sinusoidal beat technology, multi-channel synchronous acquisition technology, and digital frequency measurement technology, and uses differential compensation of system error to realize the precision measurement of atomic frequency standard. The frequency measurement accuracy is less than 2.5 × 10−14 and the noise floor is better than 6.5 × 10−15/τ = 1 s. The system has a high frequency measurement accuracy and a low noise floor, which can realize the precise measurement of a highly stable frequency source.

Refractive Index by Direct Measurement

1972 ◽  
Vol 13 (2) ◽  
pp. 78-81
Author(s):  
F. S. H. Tisdall
Keyword(s):  
Refractive Index ◽  
Direct Measurement

scholarly journals Non-Contact Respiration Measurement Method Based on RGB Camera Using 1D Convolutional Neural Networks

Sensors ◽  
2021 ◽  
Vol 21 (10) ◽  
pp. 3456
Author(s):  
Hyeon-Sang Hwang ◽  
Eui-Chul Lee
Keyword(s):  
Measurement Method ◽  
Respiratory Diseases ◽  
Region Of Interest ◽  
Average Error ◽  
Measurement Technology ◽  
Altman Analysis ◽  
Clinical Scenarios ◽  
Actual Environment ◽  
Error Bias ◽  
Robust To Noise

Conventional respiration measurement requires a separate device and/or can cause discomfort, so it is difficult to perform routinely, even for patients with respiratory diseases. The development of contactless respiration measurement technology would reduce discomfort and help detect and prevent fatal diseases. Therefore, we propose a respiration measurement method using a learning-based region-of-interest detector and a clustering-based respiration pixel estimation technique. The proposed method consists of a model for classifying whether a pixel conveys respiration information based on its variance and a method for classifying pixels with clear breathing components using the symmetry of the respiration signals. The proposed method was evaluated with the data of 14 men and women acquired in an actual environment, and it was confirmed that the average error was within approximately 0.1 bpm. In addition, a Bland–Altman analysis confirmed that the measurement result had no error bias, and regression analysis confirmed that the correlation of the results with the reference is high. The proposed method, designed to be inexpensive, fast, and robust to noise, is potentially suitable for practical use in clinical scenarios.

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