A new method for Q estimation : the generalized central frequency shift

2018 ◽  
Author(s):  
Ke Yan ◽  
Jinghai Gao ◽  
Bing Zhang ◽  
Jinghai Gao
Keyword(s):  
Frequency Shift ◽  
New Method ◽  
Central Frequency

On a new method in spectroscopy : laser-induced frequency shift of self-excited ion oscillations

1992 ◽  
Vol 2 (7) ◽  
pp. 1367-1372
Author(s):  
R. C. Bobulescu ◽  
M. A. Brǎtescu ◽  
C. Stǎnciulescu ◽  
G. Musa
Keyword(s):  
Frequency Shift ◽  
New Method ◽  
Spectroscopy Laser

scholarly journals Multi-Addressed Fiber Bragg Structures for Microwave-Photonic Sensor Systems

Sensors ◽  
2020 ◽  
Vol 20 (9) ◽  
pp. 2693 ◽  
Author(s):  
Oleg Morozov ◽  
Airat Sakhabutdinov ◽  
Vladimir Anfinogentov ◽  
Rinat Misbakhov ◽  
Artem Kuznetsov ◽  
...  
Keyword(s):  
Frequency Shift ◽  
Microwave Frequency ◽  
Optical Signal ◽  
Electrical Signal ◽  
Infrared Range ◽  
Electromagnetic Spectrum ◽  
Sensor Systems ◽  
Central Frequency ◽  
Bragg Structure ◽  
Microwave Photonic

The new theory and technique of Multi-Addressed Fiber Bragg Structure (MAFBS) usage in Microwave Photonics Sensor Systems (MPSS) is presented. This theory is the logical evolution of the theory of Addressed Fiber Bragg Structure (AFBS) usage as sensors in MPSS. The mathematical model of additive response from a single MAFBS is presented. The MAFBS is a special type of Fiber Bragg Gratings (FBG), the reflection spectrum of which has three (or more) narrow notches. The frequencies of narrow notches are located in the infrared range of electromagnetic spectrum, while differences between them are located in the microwave frequency range. All cross-differences between optical frequencies of single MAFBS are called the address frequencies set. When the additive optical response from a single MAFBS, passed through an optic filter with an oblique amplitude–frequency characteristic, is received on a photodetector, the complex electrical signal, which consists of all cross-frequency beatings of all optical frequencies, which are included in this optical signal, is taken at its output. This complex electrical signal at the photodetector’s output contains enough information to determine the central frequency shift of the MAFBS. The method of address frequencies analysis with the microwave-photonic measuring conversion method, which allows us to define the central frequency shift of a single MAFBS, is discussed in the work.

scholarly journals NEW METHOD FOR FAST IMAGE EDGE DETECTION BASED ON SUBBAND DECOMPOSITION

2011 ◽  
Vol 20 (1) ◽  
pp. 53 ◽  
Author(s):  
Chong-Yang Hao ◽  
Min Qi ◽  
U Heute ◽  
C Moraga
Keyword(s):  
Edge Detection ◽  
Frequency Spectrum ◽  
Spectrum Analysis ◽  
New Method ◽  
Subband Decomposition ◽  
Central Frequency ◽  
Spatial Methods ◽  
Image Edge Detection ◽  
Image Edge ◽  
Simulation Results

A new method of detection the edges of an image is presented in this article. The method uses a kind of twodimensional subband spectrum analysis (2D-SSA) filter that is based on subband decomposition, and it is very convenient to get the edge frequency spectrum of an image after certain preprocessing. Comparing with spatial methods, the method is less sensitive to noise. It is also superior to the conventional frequency methods. In conventional frequency methods, the bandwidth and central frequency of filter are fixed, and it needs to transform the whole image into frequency domain. While in this method, the bandwidth and central frequency can be adjusted flexibly, and it only uses a few pixels to implement FFT. So this method is a fast way to extract the edges of an image. The simulation results show its efficiency.

scholarly journals The Application of Low-Frequency Transition in the Assessment of the Second-Order Zeeman Frequency Shift

Sensors ◽  
2021 ◽  
Vol 21 (24) ◽  
pp. 8333
Author(s):  
Yang Bai ◽  
Xinliang Wang ◽  
Junru Shi ◽  
Fan Yang ◽  
Jun Ruan ◽  
...  
Keyword(s):  
Magnetic Field ◽  
Frequency Shift ◽  
Low Frequency ◽  
Pulse Signal ◽  
Second Order ◽  
Magnetic Field Measurement ◽  
Central Frequency ◽  
Zeeman Frequency ◽  
The Magnetic Field ◽  
Frequency Pulse

Second-order Zeeman frequency shift is one of the major systematic factors affecting the frequency uncertainty performance of cesium atomic fountain clock. Second-order Zeeman frequency shift is calculated by experimentally measuring the central frequency of the (1,1) or (−1,−1) magnetically sensitive Ramsey transition. The low-frequency transition method can be used to measure the magnetic field strength and to predict the central fringe of (1,1) or (−1,−1) magnetically sensitive Ramsey transition. In this paper, we deduce the formula for magnetic field measurement using the low-frequency transition method and measured the magnetic field distribution of 4 cm inside the Ramsey cavity and 32 cm along the flight region experimentally. The result shows that the magnetic field fluctuation is less than 1 nT. The influence of low-frequency pulse signal duration on the accuracy of magnetic field measurement is studied and the optimal low-frequency pulse signal duration is determined. The central fringe of (−1,−1) magnetically sensitive Ramsey transition can be predicted by using a numerical integrating of the magnetic field “map”. Comparing the predicted central fringe with that identified by Ramsey method, the frequency difference between these two is, at most, a fringe width of 0.3. We apply the experimentally measured central frequency of the (−1,−1) Ramsey transition to the Breit-Rabi formula, and the second-order Zeeman frequency shift is calculated as 131.03 × 10−15, with the uncertainty of 0.10 × 10−15.

Raman Scattering Spectroscopy of GeSi/Si Strained Layer Superlattice

1993 ◽  
Vol 298 ◽  
Author(s):  
Zhang Rong ◽  
Zheng Youdou ◽  
Gu Shulin ◽  
Hu Liqun
Keyword(s):  
Raman Scattering ◽  
Frequency Shift ◽  
Raman Spectra ◽  
Strain Distribution ◽  
Phonon Frequency ◽  
New Method ◽  
Raman Scattering Spectroscopy ◽  
Scattering Measurements ◽  
Optic Phonon ◽  
Strained Layer Superlattice

AbstractRaman scattering measurements have been carried out on Si1-xGex/Si SLS. It is found that the Ge–Ge optic phonon frequency shift is proportional to strain in the SiGe film, and the Ge–Ge strain shift coefficient is 408cm−1. Based on these study a new method for analyzing the Raman spectra of SiGe/Si SLS has been proposed. Using the new method we can obtain the composition of the alloy sublayers as well as the strain in SLS. The strain distribution in the SiGe/Si SLS has been discussed, and strain in both SiGe and Si sublayers of the SLS have been calculated.

scholarly journals A robust AFM-based method for locally measuring the elasticity of samples

2018 ◽  
Vol 9 ◽  
pp. 1-10 ◽  
Author(s):  
Alexandre Bubendorf ◽  
Stefan Walheim ◽  
Thomas Schimmel ◽  
Ernst Meyer
Keyword(s):  
Elastic Modulus ◽  
Frequency Shift ◽  
Silicon Oxide ◽  
New Method ◽  
Self Assembled Monolayer ◽  
Contact Mode ◽  
Flexural Mode ◽  
Force Microscopy ◽  
Atomic Force ◽  
Circular Holes

Investigation of the local sample elasticity is of high importance in many scientific domains. In 2014, Herruzo et al. published a new method based on frequency-modulation atomic force microscopy to locally determine the elasticity of samples (Nat. Commun. 2014, 5, 3126). This method gives evidence for the linearity of the relation between the frequency shift of the cantilever first flexural mode Δf 1 and the square of the frequency shift of the second flexural mode Δf 2 2. In the present work, we showed that a similar linear relation exists when measuring in contact mode with a certain load F N and propose a new method for determining the elastic modulus of samples from this relation. The measurements were performed in non-dry air at ambient temperature on three different polymers (polystyrene, polypropylene and linear low-density polyethylene) and a self-assembled monolayer of 1H,1H,2H,2H-perfluorodecyltrichlorosilane (FDTS) on a silicon oxide substrate perforated with circular holes prepared by polymer blend lithography. For all samples the relation was evidenced by recording Δf 1, Δf 2 and F N as a function of the Z-displacement curves of the piezoelectric scanner. The occurence of a plastic deformation followed by an elastic deformation is shown and explained. The necessary load F N for measuring in the elastic domain was assessed for each sample, used for mapping the frequency shifts Δf 1 and Δf 2 and for determining the elastic modulus from Δf 2 2/Δf 1. The method was used to give an estimate of the Young’s modulus of the FDTS thin film.

Ultra-precise time tuning and central frequency shift of optical pulses via small weak values

2018 ◽  
Vol 425 ◽  
pp. 19-23 ◽  
Author(s):  
Changliang Ren ◽  
Jiangdong Qiu ◽  
Jingling Chen ◽  
Haofei Shi
Keyword(s):  
Frequency Shift ◽  
Weak Values ◽  
Optical Pulses ◽  
Central Frequency ◽  
Precise Time

Selective Sampling and Orientation of Non-Homogeneous Tissues

1968 ◽  
Vol 26 ◽  
pp. 98-99
Author(s):  
C. C. Clawson ◽  
L. W. Anderson ◽  
R. A. Good
Keyword(s):  
Electron Microscopy ◽  
Electron Microscope ◽  
Light Microscopy ◽  
Random Sampling ◽  
New Method ◽  
Microscope Examination ◽  
Small Areas ◽  
Selective Sampling ◽  
Large Numbers ◽  
Specific Orientation

Investigations which require electron microscope examination of a few specific areas of non-homogeneous tissues make random sampling of small blocks an inefficient and unrewarding procedure. Therefore, several investigators have devised methods which allow obtaining sample blocks for electron microscopy from region of tissue previously identified by light microscopy of present here techniques which make possible: 1) sampling tissue for electron microscopy from selected areas previously identified by light microscopy of relatively large pieces of tissue; 2) dehydration and embedding large numbers of individually identified blocks while keeping each one separate; 3) a new method of maintaining specific orientation of blocks during embedding; 4) special light microscopic staining or fluorescent procedures and electron microscopy on immediately adjacent small areas of tissue.

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