scholarly journals Long-term Brillouin imaging of live cells with reduced absorption-mediated damage at 660nm wavelength

2019 ◽  
Author(s):  
Miloć Nikoliš ◽  
Giuliano Scarcelli
Keyword(s):  
Brillouin Scattering ◽  
Signal To Noise Ratio ◽  
Incident Light ◽  
Live Cells ◽  
Signal To Noise ◽  
Lasing Medium ◽  
Optimal Wavelength ◽  
Improved Accuracy ◽  
532 Nm

AbstractIn Brillouin microscopy, absorption-induced photodamage of incident light is the primary limitation on signal-to-noise ratio in many practical scenarios. Here we show that 660 nm may represent an optimal wavelength for Brillouin microscopy as it offers minimal absorption-mediated photodamage at high Brillouin scattering efficiency and the possibility to use a pure and narrow laser line from solid-state lasing medium. We demonstrate that live cells are ~80 times less susceptible to the 660 nm incident light compared to 532 nm light, which overall allows Brillouin imaging of up to more than 30 times higher SNR. We show that this improvement enables Brillouin imaging of live biological samples with improved accuracy, higher speed and/or larger fields of views with denser sampling.

A compact guided-wave EMAT with pulsed electromagnet for ferromagnetic tube inspection

2020 ◽  
Vol 64 (1-4) ◽  
pp. 951-958
Author(s):  
Tianhao Liu ◽  
Yu Jin ◽  
Cuixiang Pei ◽  
Jie Han ◽  
Zhenmao Chen
Keyword(s):  
Power Plants ◽  
Signal To Noise Ratio ◽  
Small Diameter ◽  
Performance Testing ◽  
Guided Wave ◽  
High Signal ◽  
Receiver Coil ◽  
Signal To Noise ◽  
Corrosion Defects

Small-diameter tubes that are widely used in petroleum industries and power plants experience corrosion during long-term services. In this paper, a compact inserted guided-wave EMAT with a pulsed electromagnet is proposed for small-diameter tube inspection. The proposed transducer is noncontact, compact with high signal-to-noise ratio and unattractive to ferromagnetic tubes. The proposed EMAT is designed with coils-only configuration, which consists of a pulsed electromagnet and a meander pulser/receiver coil. Both the numerical simulation and experimental results validate its feasibility on generating and receiving L(0,2) mode guided wave. The parameters for driving the proposed EMAT are optimized by performance testing. Finally, feasibility on quantification evaluation for corrosion defects was verified by experiments.

scholarly journals Assessing Stability of Crutch Users by Non-Contact Methods

2021 ◽  
Vol 18 (6) ◽  
pp. 3001
Author(s):  
Achilles Vairis ◽  
Suzana Brown ◽  
Maurice Bess ◽  
Kyu Hyun Bae ◽  
Jonathan Boyack
Keyword(s):  
Signal To Noise Ratio ◽  
Time Derivative ◽  
Assistive Devices ◽  
Signal To Noise ◽  
Physically Disabled ◽  
Significant Difference ◽  
Novice Users ◽  
Noise Ratio ◽  
Physically Disabled People

Enhancing gait stability in people who use crutches is paramount for their health. With the significant difference in gait compared to users who do not require an assistive device, the use of standard gait analysis tools to measure movement for temporary crush users and physically disabled people proves to be more challenging. In this paper, a novel approach based on video analysis is proposed as non-contact low-cost solution to the more expensive alternative with the data collected from processed videos, two values are calculated: the Signal to Noise Ratio (SNR) of acceleration, and the Signal to Noise Ratio of the jerk (time derivative of acceleration), to assess the user’s stability while they walk with crutches. The adopted methodology has been tested on a total of 10 participants. Five are temporary users of assistive devices with one being a long-term user and the other four novice users, and five are disabled participants who use those assistive devices permanently. Preliminary results show differences between novice users, long-term users, and physically disabled users. The approach is promising and could improve the assessment of crutch user stability, allowing for the correction of gait for individuals while using an inexpensive non-contact setup and preventing unnecessary falls.

scholarly journals High Signal-to-Noise Ratio Stimulated Brillouin Scattering Gain Spectrum Measurement

2018 ◽  
Author(s):  
Flavien Gyger ◽  
Zhisheng Yang ◽  
Marcelo A. Soto ◽  
Fan Yang ◽  
Kenny Hey Tow ◽  
...  
Keyword(s):  
Brillouin Scattering ◽  
Signal To Noise Ratio ◽  
Stimulated Brillouin Scattering ◽  
Gain Spectrum ◽  
High Signal ◽  
Signal To Noise ◽  
Spectrum Measurement ◽  
Noise Ratio ◽  
Stimulated Brillouin

All polarization-maintaining Er:fiber-based optical frequency comb for frequency comparison of optical clocks

2021 ◽  
Author(s):  
Zhang Pan ◽  
Zhang Yan-Yan ◽  
Li Ming-Kun ◽  
Rao Bing-Jie ◽  
Yan Lu-Lu ◽  
...  
Keyword(s):  
Frequency Comb ◽  
Signal To Noise Ratio ◽  
Frequency Instability ◽  
Optical Frequency Comb ◽  
Optical Frequency ◽  
Thermal Drift ◽  
Signal To Noise ◽  
Frequency Comparison ◽  
Polarization Maintaining

Abstract In this research, we demonstrate an optical frequency comb (OFC) based on a turnkey mode-locked laser with a figure-9 structure and polarization-maintaining fibers for frequency comparison between optical clocks with wavelengths of 698 nm, 729 nm, 1068 nm and 1156 nm. We adopt a multi-branch approach in order to produce high power OFC signals at these specific wavelengths, enabling the signal-to-noise ratio of the beatnotes between the OFC and the clock lasers beyond 30 dB at a resolution bandwidth of 300 kHz. This approach makes the supercontinuum spectra generating process much easier in comparison to a single branch OFC; however, more out-of-loop fibers degrade the long term frequency instability due to thermal drift. To minimize the thermal drift effect, we set the fiber lengths of different branches to be similar, and we stabilize the temperature as well. The out-of-loop frequency instability of the OFC due to the incoherence of the multi-branch is about 5.5×10-19 @ 4000 s, while the in-loop frequency instability of f ceo and that of f beat are 7.5×10-18 @1 s and 8.5×10-18 @1 s, respectively. The turnkey OFC meets the requirement of frequency comparison between the best optical clocks.

scholarly journals BIT ERROR RATE ANALYSIS IN DIFFERENT TERRAINS FOR LTE

2019 ◽  
Vol 7 (7) ◽  
pp. 331-339
Author(s):  
Dilshad Mahjabeen ◽  
Moshiur Rahman Tarafder ◽  
T Saikat Ahmed
Keyword(s):  
Rural Area ◽  
Bit Error Rate ◽  
Error Rate ◽  
Signal To Noise Ratio ◽  
Signal To Noise ◽  
Rate Analysis ◽  
Receiving Antenna ◽  
Noise Ratio ◽  
Clear Idea

Focus of this paper is mainly evaluating the performance of Long Term Evolution (LTE) system in different terrains such as urban, suburban and rural area. The performance parameters such as, Bit Error Rate (BER) and the Data Throughput are reported in terms of Signal to Noise Ratio (SNR). The system parameters taken into consideration are signal to noise ratio (SNR), number of receiving antenna (RxAn), reference channel and duplex mode. All of the simulations were performed in MATLAB, version 2014a simulink. The results are presented in table and graph which gives clear idea of the effect of environment on signal and receiver sensitivity. Also bit-error-rate, an important parameter in case of receiving signal, is analyzed with respect to SNR values. A comparative analysis of bit-error-rate is performed between three areas for same conditions which proves that LTE signal is well suited in a rural area than that of a suburban and urban area.

Prospective Evaluation of Cognitive Functions After Rehabilitation With Cochlear Implant or Hearing Aids: Preliminary Results of a Multicentric Study on Elderly Patients

2019 ◽  
Vol 28 (3S) ◽  
pp. 762-774 ◽  
Author(s):  
Roberta Anzivino ◽  
Guido Conti ◽  
Walter Di Nardo ◽  
Anna Rita Fetoni ◽  
Pasqualina Maria Picciotti ◽  
...  
Keyword(s):  
Executive Functions ◽  
Cochlear Implant ◽  
Cognitive Decline ◽  
Hearing Aids ◽  
Cognitive Functions ◽  
Signal To Noise Ratio ◽  
Signal To Noise ◽  
Speech In Noise

Objective Recent literature has shown a growing interest in the relationship between presbycusis and cognitive decline, but significant evidence about the long-term benefit of rehabilitation on cognitive functions has not been reported yet. The aim of the study was to analyze audiological and neuropsychological performances in patients with cochlear implant (CI) or hearing aids (HAs) over time. Materials and Method Forty-four bilaterally deaf patients aged more than 60 years (25 with CI candidacy and 19 with HA candidacy) were enrolled. Patients were subjected to audiological evaluation, to a battery of neuropsychological tests (Mini-Mental State Examination [MMSE], Rey Auditory Verbal Learning Task [RAVLT], Rey–Osterreith Complex Figure Test, Digit/Corsi Span Forward and Backward, Multiple Features Target Cancellation, Trail-Making Test, Stroop Test, and Phonological and Semantic Word Fluency), and to a quality of life assessment (Short Form 36, Glasgow Benefit Inventory, Glasgow Health Status Inventory) at the baseline and after a long-term follow-up (6–12 months). Results Speech recognition scores in quiet and in noise were significantly improved even 6 months after auditory rehabilitation. Significant differences between pre- and post-rehabilitation scores were reported in physical and emotional impacts in life, general global health, vitality, and social activities. MMSE and RAVLT scores were significantly improved in both groups after 6 months of follow-up, suggesting a global involvement of memory domain. Mnesic performances remained unchanged between the first and second follow-up, but a further significant improvement in executive functions (Stroop Test) was detected in patients with CI reevaluated 12 months after implantation. A significant correlation of the RAVLT with signal-to-noise ratio at +10 dB speech-in-noise scores and the MMSE with signal-to-noise ratio at 0 dB speech-in-noise scores suggests the pivotal role of executive functions in recognition in noisy environment. Conclusions Our preliminary data confirm that hearing deprivation in aged patients represents a truly modifiable risk factor for cognitive decline, which can be positively faced by acoustic rehabilitation. The improvement of short- and long-term memory performances and the amelioration of executive and attentive functions suggest that hearing restoration with both HAs and CI may provide a recovery of superior cognitive domains probably through a reallocation of cortical resources altered by hearing deprivation.

scholarly journals A MODWT-Based Algorithm for the Identification and Removal of Jumps/Short-Term Distortions in Displacement Measurements Used for Structural Health Monitoring

IoT ◽  
2021 ◽  
Vol 3 (1) ◽  
pp. 60-72
Author(s):  
Davi V. Q. Rodrigues ◽  
Delong Zuo ◽  
Changzhi Li
Keyword(s):  
Structural Health Monitoring ◽  
Health Monitoring ◽  
Signal To Noise Ratio ◽  
Structural Condition ◽  
Signal To Noise ◽  
Short Term ◽  
Structural Health ◽  
Noise Ratio ◽  
Displacement Measurements

Researchers have made substantial efforts to improve the measurement of structural reciprocal motion using radars in the last years. However, the signal-to-noise ratio of the radar’s received signal still plays an important role for long-term monitoring of structures that are susceptible to excessive vibration. Although the prolonged monitoring of structural deflections may provide paramount information for the assessment of structural condition, most of the existing structural health monitoring (SHM) works did not consider the challenges to handle long-term displacement measurements when the signal-to-noise ratio of the measurement is low. This may cause discontinuities in the detected reciprocal motion and can result in wrong assessments during the data analyses. This paper introduces a novel approach that uses a wavelet-based multi-resolution analysis to correct short-term distortions in the calculated displacements even when previously proposed denoising techniques are not effective. Experimental results are presented to validate and demonstrate the feasibility of the proposed algorithm. The advantages and limitations of the proposed approach are also discussed.

scholarly journals First-Arrival Picking for Microseismic Monitoring Based on Deep Learning

2021 ◽  
Vol 2021 ◽  
pp. 1-14
Author(s):  
Xiaolong Guo
Keyword(s):  
Deep Learning ◽  
High Efficiency ◽  
Signal To Noise Ratio ◽  
Microseismic Monitoring ◽  
Signal To Noise ◽  
Short Term ◽  
Real Time Processing ◽  
Monitoring Process ◽  
First Arrival

In microseismic monitoring, achieving an accurate and efficient first-arrival picking is crucial for improving the accuracy and efficiency of microseismic time-difference source location. In the era of big data, the traditional first-arrival picking method cannot meet the real-time processing requirements of microseismic monitoring process. Using the advanced idea of deep learning-based end-to-end classification and the prominent feature extraction advantages of a fully convolution neural network, this paper proposes a first-arrival picking method of effective signals for microseismic monitoring based on UNet++ network, which can significantly improve the accuracy and efficiency of first-arrival picking. In this paper, we first introduced the methodology of the UNet++-based picking method. And then, the performance of the proposed method is verified by the experiments with finite-difference forward modeling simulated signals and actual microseismic records under different signal-to-noise ratios, and finally, comparative experiments are performed using the U-Net-based first-arrival picking algorithm and the Short-Term Average to Long-Term Average (STA/LTA) algorithm. The results show that compared to the U-Net network, the proposed method can obviously improve the first-arrival picking accuracy of the low signal-to-noise ratio microseismic signals, achieving significantly higher accuracy and efficiency than the STA/LTA algorithm, which is famous for its high efficiency in traditional algorithms.

The Enhancement of a Chronically Implanted Microwire Electrode Performance

2014 ◽  
Vol 960-961 ◽  
pp. 689-694
Author(s):  
Li Shi ◽  
Jian Wei Chen ◽  
Song Wei Wang
Keyword(s):  
Surface Modification ◽  
Signal To Noise Ratio ◽  
Low Cost ◽  
Signal Acquisition ◽  
Key Factors ◽  
Signal To Noise ◽  
Factors Affecting ◽  
Fabrication Cost ◽  
Electrode Fabrication

Electrodes are expensive consumables of electrophysiological experiments. Cheap and homemade microwire electrodes have been widely applied, but their implantation performance is not good. To fabricate low cost and acceptable performance of microwire electrode, first, we analyzed the key factors affecting the long-term recording performance and determined the direction of the enhancement of electrode. We improved the existing fabrication process through electrode fabrication and the electrode tip surface modification, and systematically evaluated its properties, signal acquisition ability and biocompatibility. The result shows that the improved electrode tip surface is smooth and tidy, and its impedance decreased by 56.1% on average; record signal-to-noise ratio is higher; recording longevity reached 45 days; biocompatibility is better. It can meet the use of the general electrophysiological experimental, and electrode fabrication cost is less than 58 yuan.

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