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signal-to-noise ratio of Raman signal measured by multichannel detectors

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Chinese Physics B 2021年第9期30卷 31-44页

作者： Xue-Lu Liu Yu-Chen Leng Miao-Ling Lin Xin Cong Ping-Heng Tan State Key Laboratory of Superlattices and Microstructures Institute of SemiconductorsChinese Academy of SciencesBeijing 100083China Center of Materials Science and Optoelectronics Engineering&CAS Center of Excellence in Topological Quantum Computation University of Chinese Academy of SciencesBeijing 100049China

Raman spectroscopy has been widely used to characterize the physical properties of two-dimensional materials(2DMs).The signal-to-noise ratio(SNR or S/N ratio)of Raman signal usually serves as an important indicator to evaluate the instrumental performance rather than Raman intensity *** detectors with outstanding sensitivity,rapid acquisition speed and low noise level have been widely equipped in Raman instruments for the measurement of Raman *** this mini-review,we first introduce the recent advances of Raman spectroscopy of *** we take the most commonly used CCD detector and IGA array detector as examples to overview the various noise sources in Raman measurements and analyze their potential influences on SNR of Raman signal in *** overview can contribute to a better understanding on the SNR of Raman signal and the performance of multichannel detector for numerous researchers and instrumental design for industry,as well as offer practical strategies for improving spectral quality in routine measurement.

关键词： multichannel detectors signal-to-noise ratio dark noise shot noise

High signal-to-noise ratio Hall Devices with a 2D Structure of Dual δ-Doped GaAs/AlGaAs for Low Field Magnetometry

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Chinese Physics Letters 2015年第12期32卷 167-170页

作者：陈笛赵柏秦张新 Institute of Semiconductors Chinese Academy of Sciences Beijing 100083 Shangdong Wave of Huaguang Photonics LTD dinan 250101

Single arid dual δ-doped GaAs/AlGaAs two-dimensional electron gas （2DEG） Hall devices for low magnetic field detection at room temperature are prepared. The sensitivity and noise spectrum of the Hall devices are measured for evaluating the signal-to-noise ratio performance. It is observed that the dual δ-doped Hall devices achieve a minimum detectable magnetic field as low as 303 n T, which is better than the single δ doped Hall device prepared under the same growth condition.

关键词： GALLIUM arsenide ALUMINUM gallium arsenide lasers signal-to-noise ratio DOPING profiles (Semiconductors) MAGNETOMETERS HALL effect MAGNETIC field effects

Long scan depth optical coherence tomography on imaging accommodation: impact of enhanced axial resolution, signal-to-noise ratio and speed

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Eye and Vision 2018年第1期5卷 151-162页

作者： Yilei Shao Aizhu Tao Hong Jiang Meixiao Shen Dexi Zhu Fan Lu Carol LKarp Yufeng Ye Jianhua Wang Bascom Palmer Eye Institute University of MiamiMiamiFLUSA School of Ophthalmology and Optometry Wenzhou Medical UniversityWenzhouZhejiangChina Hangzhou First People’s Hospital HangzhouChina Electrical and Computer Engineering University of MiamiMiamiFLUSA Bascom Palmer Eye Institute University of MiamiMiller School of Medicine1638 NW 10th AvenueMcKnight Building-Room 202AMiamiFL 33136USA

Background:Spectral domain optical coherence tomography(SD-OCT)was a useful tool to study accommodation in human eye,but the maximum image depth is limited due to the decreased signal-to-noise ratio(SNR).In this study,improving optical resolutions,speeds and the SNR were achieved by custom built SD-OCT,and the evaluation of the impact of the improvement during accommodation was ***:Three systems with different spectrometer designs,including two Charge Coupled Device(CCD)cameras and one Complementary Metal-Oxide-Semiconductor Transistor(CMOS)camera,were *** measured the point spread functions of a mirror at different positions to obtain the axial resolution and the SNR of three OCT systems powered with a light source with a 50 nm bandwidth,centered at a wavelength of 840 *** normal subjects,aged 26 and 47,respectively,and one 75-year-old patient with an intraocular lens implanted were ***:The results indicated that spectrometers using cameras with 4096 camera pixels optimized the axial resolutions,due to the use of the full spectrum provided by the light *** CCD camera system with 4096 pixels had the highest SNR and the best image *** system with the CMOS camera with 4096 pixels had the highest speed but had a compromised SNR compared to the CCD camera with 4096 ***:Using these three OCT systems,we imaged the anterior segment of the human eye before and after accommodation,which showed similar results among the different *** system using the CMOS camera with an ultra-long scan depth,high resolution and high scan speed exhibited the best overall performance and therefore was recommended for imaging real-time accommodation.

关键词： Optical coherence tomography Axial resolution signal-to-noise ratio Accommodation Anterior segment

Enhancement of signal-to-noise ratio of ultracold polar NaCs molecular spectra by phase locking detection

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Chinese Physics B 2017年第12期26卷 231-235页

作者：王文浩刘文良武寄洲李玉清王晓锋刘艳艳马杰肖连团贾锁堂 State Key Laboratory of Quantum Optics and Quantum Optics Devices Institute of Laser Spectroscopy Shanxi University Collaborative Innovation Center of Extreme Optics Shanxi University

We report a method of high-sensitively detecting the weak signal in photoassociation(PA) spectra of ultracold NaCs molecules by phase sensitive-demodulated trap-loss spectra of Na atoms from a photomultiplier tube. We find that the signal-to-noise ratio(SNR) of the PA spectra is strongly dependent on the integration time and the sensitivity of the lockin amplifier, and our results show reasonable agreement with the theoretical analyses of the SNR with the demodulation parameters. Meanwhile, we investigate the effect of the interaction time of the PA laser with the colliding Na–Cs atom pairs on the SNR of the PA spectra. The atom loss rate is dependent on both the PA-induced atom loss and the loading of the MOT. The high-sensitive detection of the excited ultracold NaCs molecules lays a solid foundation for further study of the formation and application of ultracold NaCs molecules.

关键词： ultracold NaCs molecules photoassociation high-resolution spectroscopy signal-to-noise ratio

Mean-square Stabilizability vs. signal-to-noise ratio,Channel Induced Delay and Packet Dropout

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Mean-square Stabilizability vs. Signal-to-Noise Ratio,Channe...

The simulation of the signal-to-noise ratio of the optical detector in passive rubidium frequency standards

第32届中国控制与决策会议

作者： Jieying Lu Weizhou Su School of Automation Sci.and Eng. South China University of Technology

The mean-square stabilizability via output feedback is studied for a discrete-time networked linear feedback system over an unreliable communication *** is additive white noise with zero mean and constant variance in the communication *** average power of its input signal is ***,in the data transmission process,there are fixed delay and random packet dropout induced by the *** channel uncertainty is modeled as a multiplicative noise,and its variance is characterized by the random packet dropout rate and signal-to-noise ratio（SNR） between the channel input and the additive *** is assumed that the plant of the networked system is minimum *** analytic necessary and sufficient condition is presented for the mean-square stabilizability via output feedback of the networked feedback *** describes the trade-off among the SNR,the packet dropout rate,the channel delay and unstable poles of the plant in the mean-square stabilizability.

关键词： Networked feedback system mean-square stabilizability random transmission delay signal-to-noise ratio relative degree output feedback

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The simulation of the signal-to-noise ratio of the optical d...

Using Pearson’s System of Curves to Approximate the Distributions of the Difference between Two Correlated Estimates of signal-to-noise ratios: The Cases of Bivariate Normal and Bivariate Lognormal Distributions

2011年全国压电和声波理论及器件应用研讨会

作者： Dong Liu Xian-he Huang~* Yan Wang School of Automation,University of Electronic Science and Technology of China,Chengdu 610054

＜正＞Vanier has pointed out that the signal-to-noise ratio（SNR） of the optical detector has a significant impact on the short-term stability of passive rubidium frequency *** this Article,the harmonic content of th... 详细信息

关键词： Rubidium frequency standards signal-to-noise ratio Reverse

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Open Journal of Statistics 2024年第3期14卷 207-227页

作者： Mohamed M. Shoukri Department of Epidemiology and Biostatistics Schulich School of Medicine and Dentistry University of Western Ontario London Ontario Canada

Background: The signal-to-noise ratio (SNR) is recognized as an index of measurements reproducibility. We derive the maximum likelihood estimators of SNR and discuss confidence interval construction on the difference between two correlated SNRs when the readings are from bivariate normal and bivariate lognormal distribution. We use the Pearsons system of curves to approximate the difference between the two estimates and use the bootstrap methods to validate the approximate distributions of the statistic of interest. Methods: The paper uses the delta method to find the first four central moments, and hence the skewness and kurtosis which are important in the determination of the parameters of the Pearsons distribution. Results: The approach is illustrated in two examples;one from veterinary microbiology and food safety data and the other on data from clinical medicine. We derived the four central moments of the target statistics, together with the bootstrap method to evaluate the parameters of Pearsons distribution. The fitted Pearsons curves of Types I and II were recommended based on the available data. The R-codes are also provided to be readily used by the readers.

关键词： signal-to-noise ratio Bivariate Distributions Bootstrap Methods Delta Method Pearson System of Curves

To improve robustness of mechanical properties of semi-solid cast A356 alloy using taguchi design method

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China Foundry 2024年第2期21卷 175-184页

作者： Yi-wu Xu Hong-yi Zhan Wei Tong Jin-ping Li Le-peng Zhang De-jiang Li Xiao-qin Zeng School of Materials Science and Engineering Shanghai Jiao Tong UniversityShanghai 200240China China Science Lab General Motors Global Research&DevelopmentShanghai 201206China General Motors(China)Investment Co. Ltd.Shanghai 201206China China International Intellectech Corporation(CIIC) Beijing 100004China

Mechanical properties of semi-solid casting are dependent on multiple processing parameters,and improper processing parameters will not only reduce mean data but also increase *** present study investigated the impact of parameters in slurry preparation and heat treatment on the yield strength and ductility of T6 heat-treated A356 Al-Si alloy using rapid slurry forming(RSF)semi-solid *** focus was primarily on the robustness of mechanical properties based on Taguchi design *** analyzing signal-to-noise ratio and minimum value calculated from-3S,the optimum slurry preparation parameters and heat treatment parameters were determined to be no quench,enthalpy exchange material(EEM)temperature of 140℃,EEM-to-melt ratio of 6mass%,stirring time of 18 s,solution heat treated at 520℃ for 2 h,and ageing heat treated at 190℃ for 6 *** a small batch validation,the-3S yield strength and-3S elongation reach 256.1 MPa and 5.03% respectively,showing a satisfactory *** hardness and microstructure of heat-treated samples with the best and worst properties were characterized to gain insight into the underlying mechanisms affecting the mean value and variations of mechanical properties.

关键词： semi-solid casting taguchi design method signal-to-noise ratio mechanical property microstructure

Analytical and NumericalMethods to Study the MFPT and SR of a Stochastic Tumor-Immune Model

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Computer Modeling in Engineering & Sciences 2024年第3期138卷 2177-2199页

作者： Ying Zhang Wei Li Guidong Yang Snezana Kirin School of Mathematics and Statistics Xidian UniversityXi’an710071China Innovation Center of Faculty of Mechanical Engineering Belgrade11100Serbia

The Mean First-Passage Time (MFPT) and Stochastic Resonance (SR) of a stochastic tumor-immune model withnoise perturbation are discussed in this paper. Firstly, considering environmental perturbation, Gaussian whitenoise and Gaussian colored noise are introduced into a tumor growth model under immune surveillance. Asfollows, the long-time evolution of the tumor characterized by the Stationary Probability Density (SPD) and MFPTis obtained in theory on the basis of the Approximated Fokker-Planck Equation (AFPE). Herein the recurrenceof the tumor from the extinction state to the tumor-present state is more concerned in this paper. A moreefficient algorithmof Back-Propagation Neural Network (BPNN) is utilized in order to testify the correction of thetheoretical *** the existence of aweak signal, the functional relationship between signal-to-noiseratio (SNR), noise intensities and correlation time is also studied. Numerical results show that both multiplicativeGaussian colored noise and additive Gaussian white noise can promote the extinction of the tumors, and themultiplicative Gaussian colored noise can lead to the resonance-like peak on MFPT curves, while the increasingintensity of the additiveGaussian white noise results in theminimum of MFPT. In addition, the correlation timesare negatively correlated with MFPT. As for the SNR, we find the intensities of both the Gaussian white noise andthe Gaussian colored noise, as well as their correlation intensity can induce SR. Especially, SNR is monotonouslyincreased in the case ofGaussian white noisewith the change of the correlation *** last, the optimal parametersin BPNN structure are analyzed for MFPT from three aspects: the penalty factors, the number of neural networklayers and the number of nodes in each layer.

关键词： Stochastic tumor-immune model mean first-passage time stochastic resonance signal-to-noise ratio back-propagation neural network