The effect of RF excitation frequency on the spectrum characteristics of rubidium electrodeless lamp

2020 ◽  
Author(s):  
Weiwei Wang ◽  
Lijun Du ◽  
Rongyan Zhang ◽  
Yansong Meng ◽  
Jun Xie
Keyword(s):  
Excitation Frequency ◽  
Spectrum Characteristics ◽  
Electrodeless Lamp ◽  
Rf Excitation

A new method of fluxgate signal extraction

2017 ◽  
Vol 2017 (45) ◽  
pp. 83-89
Author(s):  
A.A. Marusenkov ◽  
Keyword(s):  
High Frequency ◽  
Second Harmonic ◽  
Excitation Frequency ◽  
Low Noise ◽  
Measuring System ◽  
Signal Extraction ◽  
Fluxgate Magnetometer ◽  
New Approach ◽  
Average Value ◽  
The Time Domain

Using dedicated high-frequency measuring system the distribution of the Barkhausen jumps intensity along a reversal magnetization cycle was investigated for low noise fluxgate sensors of various core shapes. It is shown that Barkhausen (reversal magnetization) noise intensity is strongly inhomogeneous during an excitation cycle. In the traditional second harmonic fluxgate magnetometers the signals are extracted in the frequency domain, as a result, some average value of reversal magnetization noises is contributed to the output signals. In order to fit better the noise shape and minimize its transfer to the magnetometer output the new approach for demodulating signals of these sensors is proposed. The new demodulating method is based on information extraction in the time domain taking into account the statistical properties of cyclic reversal magnetization noises. This approach yields considerable reduction of the fluxgate magnetometer noise in comparison with demodulation of the signal filtered at the second harmonic of the excitation frequency.

Chloroplast Ultrastructure and Emission Fluorescence Spectrum Characteristics for Stems of Phyllostachys pubescens

2014 ◽  
Vol 48 (6) ◽  
pp. 635-642
Author(s):  
Chen Dengju ◽  
Gao Peijun ◽  
Wu Xingbo ◽  
Gao Yan ◽  
Wen Guosheng ◽  
...  
Keyword(s):  
Fluorescence Spectrum ◽  
Chloroplast Ultrastructure ◽  
Phyllostachys Pubescens ◽  
Spectrum Characteristics

Cold plasma technique as a pretreatment for drying fruits: evaluation of the excitation frequency on drying process and bioactive compounds

2021 ◽  
pp. 110462
Author(s):  
Andria da C. Loureiro ◽  
Francisca das C. do A. Souza ◽  
Edgar A. Sanches ◽  
Jaqueline de A. Bezerra ◽  
Carlos Victor Lamarão ◽  
...  
Keyword(s):  
Bioactive Compounds ◽  
Cold Plasma ◽  
Excitation Frequency ◽  
Drying Process ◽  
Plasma Technique

scholarly journals Stereo-DIC Measurements of a Vibrating Bladed Disk: In-Depth Analysis of Full-Field Deformed Shapes

2021 ◽  
Vol 11 (12) ◽  
pp. 5430
Author(s):  
Paolo Neri ◽  
Alessandro Paoli ◽  
Ciro Santus
Keyword(s):  
Single Point ◽  
Excitation Frequency ◽  
Phase Variation ◽  
Operating Conditions ◽  
Image Correlation ◽  
Response Analysis ◽  
Full Field ◽  
Low Speed ◽  
Bladed Disk ◽  
Depth Analysis

Vibration measurements of turbomachinery components are of utmost importance to characterize the dynamic behavior of rotating machines, thus preventing undesired operating conditions. Local techniques such as strain gauges or laser Doppler vibrometers are usually adopted to collect vibration data. However, these approaches provide single-point and generally 1D measurements. The present work proposes an optical technique, which uses two low-speed cameras, a multimedia projector, and three-dimensional digital image correlation (3D-DIC) to provide full-field measurements of a bladed disk undergoing harmonic response analysis (i.e., pure sinusoidal excitation) in the kHz range. The proposed approach exploits a downsampling strategy to overcome the limitations introduced by low-speed cameras. The developed experimental setup was used to measure the response of a bladed disk subjected to an excitation frequency above 6 kHz, providing a deep insight in the deformed shapes, in terms of amplitude and phase distributions, which could not be feasible with single-point sensors. Results demonstrated the system’s effectiveness in measuring amplitudes of few microns, also evidencing blade mistuning effects. A deeper insight into the deformed shape analysis was provided by considering the phase maps on the entire blisk geometry, and phase variation lines were observed on the blades for high excitation frequency.

scholarly journals Complex response analysis of a non-smooth oscillator under harmonic and random excitations

2021 ◽  
Vol 42 (5) ◽  
pp. 641-648
Author(s):  
Shichao Ma ◽  
Xin Ning ◽  
Liang Wang ◽  
Wantao Jia ◽  
Wei Xu
Keyword(s):  
Excitation Frequency ◽  
System Stability ◽  
Response Analysis ◽  
External Excitation ◽  
Stochastic Response ◽  
Impact Oscillator ◽  
Nonlinear Parameters ◽  
Bifurcation Phenomena ◽  
Mc Simulation ◽  
Smooth System

AbstractIt is well-known that practical vibro-impact systems are often influenced by random perturbations and external excitation forces, making it challenging to carry out the research of this category of complex systems with non-smooth characteristics. To address this problem, by adequately utilizing the stochastic response analysis approach and performing the stochastic response for the considered non-smooth system with the external excitation force and white noise excitation, a modified conducting process has proposed. Taking the multiple nonlinear parameters, the non-smooth parameters, and the external excitation frequency into consideration, the steady-state stochastic P-bifurcation phenomena of an elastic impact oscillator are discussed. It can be found that the system parameters can make the system stability topology change. The effectiveness of the proposed method is verified and demonstrated by the Monte Carlo (MC) simulation. Consequently, the conclusions show that the process can be applied to stochastic non-autonomous and non-smooth systems.

Radiofrequency Exposure in Schools' Environment Reveals Spectrum Characteristics: The Role of Public Information

2020 ◽  
Vol 41 (7) ◽  
pp. 558-564
Author(s):  
Charilaos Tyrakis ◽  
Georgios A. Gourzoulidis ◽  
Yiannis Kiouvrekis ◽  
Aris Alexias ◽  
Mohammed Alkhorayef ◽  
...  
Keyword(s):  
Public Information ◽  
Spectrum Characteristics
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