scholarly journals Spectral analysis of sphygmogram

2019 ◽  
Keyword(s):  
Spectral Analysis ◽  
Optical Sensor ◽  
Light Emitting Diode ◽  
The State ◽  
Low Frequencies ◽  
Light Emitting ◽  
Computer Methods ◽  
Heart Work ◽  
The One ◽  
Methods Of Control

Actuality. The heart system executes the important role in the organism. It is important task of medicine to diagnose of the state of this system. Electrocardiogram is the one of methods of control its state. Cardiointervalgram is another way of study of the state of the heart system. I studies the change of rhythm of heart as reaction of organism on external influences. Sphygmografia is the method of graphic registration of pulses vibrations of vessels, allowing to judge about their resiliently-viscid properties. The method of registration is used by a pair light-emitting diode and photo-diode. A signal, which is forming is due to the change of volume of blood in the place of indication. The most comfortable place for the location of sensor is the finger of Purpose of work. The spectral analysis of the sphygmogram impulses gives the information about heart system. The spectrum of sphygmogram of healthy man is wider. Numeral coefficients, which are characterizing correlation high and low frequencies, are offered. This was offered to analysis the spectrum of signal from the optical sensor, which is containing information by the of impulses and cardiountervals. These signals contain more information, than cardiointervalgram and single impulse of sfigmogram only. Methods. The spectrums of signals from the optics-electronic sensor was analyzed by computer methods. Results. The spectrum of cardiointervalgram contains information about the slow waves of heart work. The spectrum of sphygmogram contains information about frequency of heart work and about higher frequencies also. Conclusion. The analysis of heart work was made by the spectrum of cardiointervalgram and on the spectrum of sphygmogram. The second method allows to obtain more information about health of man.

scholarly journals New wavelength calibration of the HARPS spectrograph

2019 ◽  
Vol 629 ◽  
pp. A27 ◽  
Author(s):  
A. Coffinet ◽  
C. Lovis ◽  
X. Dumusque ◽  
F. Pepe
Keyword(s):  
Radial Velocity ◽  
Frequency Comb ◽  
Light Emitting Diode ◽  
Laser Frequency ◽  
Wavelength Calibration ◽  
Light Emitting ◽  
Before And After ◽  
Doppler Spectroscopy ◽  
One Year ◽  
The One

Context. Doppler spectroscopy has been used in astronomy for more than 150 yr. In particular, it has permitted us to detect hundreds of exoplanets over the past 20 yr, and the goal today of detecting Earth-like planets requires a precision around 0.1 m s−1 or better. Doppler spectroscopy has also been and will be of major importance for other studies such as the variability of fundamental constants and cosmological studies. For all these applications, it is crucial to have the best possible wavelength calibration. Despite the fact that the HARPS spectrograph has been operational at the 3.6-m ESO telescope for more than 15 yr, and that it provides among the most precise Doppler measurements, improvements are still possible. One known problem, for instance, is the non-fully regular block-stitching of the charge-coupled devices (CCDs), which in some cases introduces one-year period parasitic signals in the measured radial velocity. Aims. The aim of the presented work is to improve the wavelength calibration of the HARPS spectrograph to push further its planet-detection capabilities. Methods. The properties of the CCD stitching-induced pixel-size anomalies were determined with light-emitting-diode (LED) flat-field frames, and then a physical, gap-corrected map of the CCDs is used for the fitting model of the spectral orders. We also used a new thorium line list, based on much higher-accuracy measurements than the one used up to now. We derive new wavelength solutions for the 15 yr of HARPS data, both before and after the fibre upgrade that took place in 2015. Results. We demonstrate that we do indeed correct the gap anomalies by computing the wavelength solutions of laser frequency comb exposures, known to have a very low dispersion, both with and without taking the gap correction into account. By comparing the rms of the most stable stars of the HARPS sample, we show that we globally decrease the radial velocity (RV) dispersion of the data, especially for the data acquired after the change of fibres of 2015. Finally, the comparative analysis of several individual systems shows that we manage to attenuate the periodogram power at one year in most cases. The analysis of the RVs derived from individual stellar lines also shows that we indeed correct the stitching-induced RV variation. Conclusions. This improved calibration of the HARPS spectrograph allows to go deeper in the search for low-amplitude radial-velocity signals. This new calibration process will be further improved by combining the thorium calibration spectra with laser frequency comb and Fabry–Perot calibration spectra, and this will not only be used for HARPS but notably also for HARPS-N and the new ESPRESSO spectrograph.

scholarly journals Data Communication Security Issues of Wi-Fi over Li-Fi

2019 ◽  
Vol 8 (3) ◽  
pp. 1977-1981
Keyword(s):  
Light Emitting Diode ◽  
Denial Of Service ◽  
Data Communication ◽  
Electrical Signal ◽  
Visible Light Communications ◽  
Light Emitting ◽  
Security Issues ◽  
The One ◽  
Audio Video ◽  
Led Lights

Visible Light Communications (VLC) system is called Light Fidelity One such example, analog data is passed to a LED (Light-Emitting Diode) bulb (using signal processing technology), after that it transmits data (which is implanted in its beam) to the detector or photodiode. The small commutes in the brisk feeble of LED bulbs is modulated by the receiver circuit into electrical signal. The signal is then reversed into a duplex data runnel that could be recognized in the same way that of audio, video and web programs that run on devices that has internet enabled. Wi-Fi is vulnerable to breaches involving various security issues such as Rouge Access Points, Denial of Service, Wireless Trespasser, Data Interruption, End point attacks etc. To overcome such restrictions, this paper proposes application level substructure for data communication using Li-Fi (Light Fidelity) Technology. By using LED lights as a transmission medium, the indoor wireless communication is achieved in much faster rate than the one WiFi (Wireless Fidelity) can provide.

scholarly journals Lifetime and optical analyses of LED lamps

2021 ◽  
Vol 40 (1) ◽  
Author(s):  
Emerson Roberto Santos ◽  
Hélio Akira Furuya ◽  
Elvo Calixto Burini Junior
Keyword(s):  
Light Emitting Diode ◽  
The Other ◽  
Optical Characteristics ◽  
Integrating Sphere ◽  
Initial Moment ◽  
Direct Relation ◽  
Light Emitting ◽  
Elapsed Time ◽  
The One

In this study, optical and lifetime analyses of commercial light-emitting diode (LED) lamps were carried out with the objective to better understand these characteristics. Lamps of different manufacturers and powers were used: Ourolux of 9 watts, Kian of 9 watts, Black+Decker of 9 watts, FLC of 8 watts, Galaxy of 7 watts and Brilia of 7 watts. These LED lamps remained on by 24 hours/day for 4,291.16 hours. Illuminance measurements were analyzed once a week by each lamp inside the integrating sphere with a sensor of lux meter coupled. Results showed decrease of illuminance by elapsed time, due to the degradation. Results of the illuminance obtained between the initial moment of the experiment and the final one were calculated, revealing degradation of 19% to Ourolux, 20% to FLC, 26% to Black+Decker, 28% to Kian, 29% to Galaxy and 33% to Brilia. This study suggests that the diffusers can have different transmittance values interfering on the illuminance, since the FLC LED lamp presented illuminance with highest values than the other LED lamps tested with similar electrical and optical characteristics. This experiment showed that the nominal power of the LED lamp has no direct relation to the illuminance and, comparing the lifetime, the LED lamp manufactured by Black+Decker was the only one to reach 5,521 hours, that is a lifetime much shorter than the one described at the packages (25,000 hours) for all LED lamps tested

Blue-green light-emitting diode with patterned electrode: Spectral analysis

2019 ◽  
Vol 212 ◽  
pp. 37-41
Author(s):  
Y. Nishidate ◽  
I. Khmyrova ◽  
Yu. Kholopova ◽  
E. Polushkin ◽  
V. Zemlyakov ◽  
...  
Keyword(s):  
Spectral Analysis ◽  
Light Emitting Diode ◽  
Green Light ◽  
Light Emitting

Analysis of Modified Current Controller and its Implementation in Automotive LED

2017 ◽  
Vol 6 (04) ◽  
pp. 01-06
Author(s):  
Prof. Bhushan Thakre, Dr. R.M Thakre
Keyword(s):  
Supply Voltage ◽  
Light Emitting Diode ◽  
Control Voltage ◽  
Process Technology ◽  
Light Emitting ◽  
Led Lighting ◽  
Current Controller ◽  
Dimming Control ◽  
Simulation Purpose ◽  
The One

A novel highly dimmable current controller which is a linear one is employed in the application of low power automotive is discussed here. Light Emitting Diode is the one which drives current that is linearly controlled to decrease the intensity of LED to limit the destruction of the LED and improve its reliability. Although many dimming techniques for LED lighting are available, our proposed method outperforms the existing methods in terms of power consumption and the no. of transistors used in the proposed design. This emits 100mA and decrease the LED current which is going linearly based on the theory of dimming control voltage. Toggling of LED is avoided finally in comparison with the existing system. This circuit is developed in 0.18μm process technology and Cadence ADE with Spectre is employed for simulation purpose. The proposed method utilizes a maximum power of 392.85 mW when the supply voltage is 4V and the control voltage is 4V at the temperature of 27oC.

Thermal Analyses of LED Light Bars and Backlight Modules

2016 ◽  
Vol 33 (3) ◽  
pp. 331-339 ◽  
Author(s):  
M.-Y. Tsai ◽  
C.-Y. Tang ◽  
C.-E. Zheng ◽  
Y.-Y. Tsai ◽  
C.-H. Chen
Keyword(s):  
Heat Dissipation ◽  
Light Emitting Diode ◽  
Thermal Analyses ◽  
Heat Sinks ◽  
Junction Temperature ◽  
Thermal Interface Materials ◽  
Light Emitting ◽  
Led Light ◽  
The One ◽  
Interface Materials

AbstractThe effects of various parameters, such as thermal properties of substrates, thermal interface materials (TIMs) and heat sinks on the thermal performance of the light emitting diode (LED) light bars and backlight module are investigated experimentally and numerically in terms of junction temperature (Tj) and thermal resistances from junction to air (Rj-a). The results show that the measured Rj-a of the light bars by powering-on five LEDs in the test is different from one by powering-on only one LED, resulting from the extra heat coming from the adjacent LED packages affecting the Tj for the case of powering-on five LEDs. For the modules, Rj-a is significantly reduced by using the heat sinks for all backlight modules, and aluminum and iron heat sinks do not show any obvious difference in heat dissipation along with any substrates and TIMs. Furthermore, both experimental and simulation results show that the thermal conductivity of the substrates are more important and dominant than TIM and heat sink for the Rj-a of the backlight modules concerned, and also demonstrate that the thermal field for the local model can represent the one in full-scale backlight module.

Self‐detecting light‐emitting diode optical sensor

1984 ◽  
Vol 56 (3) ◽  
pp. 869-871 ◽  
Author(s):  
Mark Johnson ◽  
Nan Marie Jokerst
Keyword(s):  
Optical Sensor ◽  
Light Emitting Diode ◽  
Light Emitting

scholarly journals Dependence of Irradiated High-Power Electromagnetic Waves on the Failure Threshold Time of Semiconductors Using a Closed Waveguide

Electronics ◽  
2021 ◽  
Vol 10 (16) ◽  
pp. 1884
Author(s):  
Sun-Hong Min ◽  
Jung-Il Kim ◽  
Matlabjon Sattorov ◽  
Seontae Kim ◽  
Dongpyo Hong ◽  
...  
Keyword(s):  
Electric Field ◽  
High Power ◽  
Integrated Circuit ◽  
Electromagnetic Waves ◽  
Light Emitting Diode ◽  
The State ◽  
Light Emitting ◽  
Threshold Time ◽  
The Impact

The failure threshold time of semiconductors caused by the impact of irradiated high-power electromagnetic waves (HPEM) is experimentally studied. A SN7442 integrated circuit (IC) is placed in an emulator with a WR430 closed waveguide and is irradiated by HPEM generated from a magnetron oscillator. The state of the SN7442 component is observed by a light-emitting diode (LED) detector and the voltage measured in the SN7442 component. As the magnitude of the electric field in the HPEM is varied from 24 kV/m to 36 kV/m, the failure threshold time falls from 195 s to 17 s with dependence of the irradiated electric field (E) on the failure threshold time (T) from T~E−12 to a T~E−6.

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