scholarly journals OXIGÊNIO NO CONTEXTO DA COVID-19: O QUE SABEMOS SOBRE A MOLÉCULA QUE RESPIRAMOS E O PAPEL CENTRAL DA QUÍMICA

Química Nova ◽  
2021 ◽  
Author(s):  
Bruna Cerqueira ◽  
Bruna Silva ◽  
Rafael Campos ◽  
Lourenço Santana ◽  
Wilson Lopes ◽  
...  
Keyword(s):  
Light Emitting Diode ◽  
Chemical Characterization ◽  
Point Of View ◽  
Oxygen Production ◽  
Oxygen Saturation Level ◽  
Light Emitting ◽  
Physical Chemical ◽  
Oxygen Cycle ◽  
Oxygen Concentrator

OXYGEN IN THE COVID-19 CONTEXT: WHAT WE KNOW ABOUT THE MOLECULE WE BREATHE AND THE CENTRAL ROLE OF CHEMISTRY. In this work, the role of chemistry in the coronavirus disease 2019 (COVID-19) pandemic is highlighted through the medical oxygen supply crises in Brazil, as an example of oxygen utility in health. Starting from oxygen chemical characterization, the oxygen cycle in nature is discussed to show how oxygen is formed through photosynthesis, followed by the description of the industrial oxygen production from atmospheric air, including physical-chemical aspects. The use of medical oxygen concentrator is presented and how this device works from the chemical point of view. Besides, the noninvasive and painless oximetry is described in terms of how oxygen saturation level in blood is measured using LED - light emitting diode.

Anode modification of polymer light-emitting diode using graphene oxide interfacial layer: The role of ultraviolet-ozone treatment

2013 ◽  
Vol 103 (7) ◽  
pp. 073305 ◽  
Author(s):  
Xiao-Chen Jiang ◽  
Yan-Qing Li ◽  
Yan-Hong Deng ◽  
Qi-Qi Zhuo ◽  
Shuit-Tong Lee ◽  
...  
Keyword(s):  
Graphene Oxide ◽  
Interfacial Layer ◽  
Light Emitting Diode ◽  
Ozone Treatment ◽  
Light Emitting ◽  
Anode Modification ◽  
Polymer Light Emitting Diode

The role of poly(3,4-ethylenedioxythiophene):poly(styrenesulphonate) as a hole injection layer in a blue-emitting polymer light-emitting diode

2008 ◽  
Vol 104 (10) ◽  
pp. 104506 ◽  
Author(s):  
Sebastian Bange ◽  
Andriy Kuksov ◽  
Dieter Neher ◽  
Antje Vollmer ◽  
Norbert Koch ◽  
...  
Keyword(s):  
Light Emitting Diode ◽  
Hole Injection ◽  
Light Emitting ◽  
Hole Injection Layer ◽  
Polymer Light Emitting Diode

Factors affecting the intention to adopt light-emitting diode lighting at home

2020 ◽  
Vol 52 (8) ◽  
pp. 1020-1039 ◽  
Author(s):  
NI Jaafar ◽  
A Sulaiman ◽  
S Moghavvemi ◽  
FP Tajudeen ◽  
F Dehdar
Keyword(s):  
Light Emitting Diodes ◽  
Light Emitting Diode ◽  
Intention To Use ◽  
Factors Affecting ◽  
Light Emitting ◽  
Mediating Role ◽  
Intention To Adopt ◽  
Use Of Technology ◽  
The Relationship

This study investigates the significant factors affecting the adoption of light emitting diode lighting among households in Malaysia by conceptualizing and extending the unified theory of acceptance and use of technology through the adaptation of price value and the anticipated emotions of pride and guilt within the model. This study used the partial least squares technique to validate measurements and to test the research hypotheses. The results obtained from analysing 1075 valid survey questionnaires revealed the effects of performance expectancy, effort expectancy and price value on the intention to use light-emitting diodes among Malaysian households. While the results support the mediating role of attitude between the three variables and intention to use light-emitting diodes, the moderating role of anticipated pride on the relationship between attitude and intention to use light-emitting diodes was not supported. The findings confirm that guilt significantly moderates the relationship between attitude and intention.

scholarly journals Light-emitting diode assessment of dentinal defects: the role of presumed extraction forces

2017 ◽  
Vol 42 (3) ◽  
pp. 232 ◽  
Author(s):  
Marcelo Santos Coelho ◽  
Steven J. Card ◽  
Peter Z. Tawil
Keyword(s):  
Light Emitting Diode ◽  
Light Emitting

High Power 325 Light Emitting Diode Arrays by Flip-Chip Packaging

2002 ◽  
Vol 743 ◽  
Author(s):  
Ashay Chitnis ◽  
Maxim Shatalov ◽  
Vinod Adivarahan ◽  
Jian Ping Zhang ◽  
Shuai Wu ◽  
...  
Keyword(s):  
Thermal Management ◽  
Flip Chip ◽  
Heat Dissipation ◽  
Light Emitting Diodes ◽  
Light Emitting Diode ◽  
Light Emitting ◽  
Flip Chip Packaging ◽  
Ultraviolet Light Emitting Diodes ◽  
Emission Light

ABSTRACTWe report flip-chip 325 nm emission light emitting diodes over sapphire with dc powers as high as 0.84 mW at 180mA and pulse powers as high as 6.68 mW at 1A. These values to date are the highest reported powers for such short wavelength emitters. Our data shows the device output power under dc operation to be limited by the package heat dissipation. A study is presented to determine the role of thermal management in controlling the power output for the reported 325 nm ultraviolet light emitting diodes.

Research Into Irradiation Conditions With Led Phyto-Irradiators in Cucumber Plants Cultivating by Photoculture Technology

2021 ◽  
pp. 56-61
Author(s):  
Alexander E. Kurshev ◽  
Sergey D. Bogatyrev ◽  
Olga E. Zheleznikova ◽  
Kirill A. Chmil
Keyword(s):  
Light Emitting Diode ◽  
Methodological Approach ◽  
Experimental Studies ◽  
Point Of View ◽  
Practical Significance ◽  
State University ◽  
Light Emitting ◽  
White Leds ◽  
Biochemical Processes ◽  
Growing Seasons

The article presents the results of two full vegetation growing seasons for Svyatogor F1 cucumber plants sort in photoculture conditions. The studies were carried out on an experimental research hydroponic installation (ERHI) under photosynthetically active photon irradiance EPPFD = (250 ± 10) μmol/s·m2. In the experiment, we used phyto-irradiators (PI) with high-pressure sodium lamps (HPSL) of the DNaZ type, as well as light emitting diode (LED) phyto-irradiators of the combined spectrum. A methodological approach to photobiological research (PBR) in the artificial climate laboratory at the Ogarev Mordovia State University was developed, which allowed us to determine the effect of the radiation of the LED PI combined spectrum on the productivity of cucumber plants under photoculture conditions. On the basis of the conducted experimental studies, it was found that the quality of seedlings grown under a phyto-irradiator with a HPSL of the DNaZ type is better than under a LED PI of the combined spectrum. From the point of view of the productivity of cucumber plants of this variety, the spectrum created by the radiation of white LEDs and radiation of LEDs with peak wavelengths λ = 660 nm and λ = 730 nm turned out to be more favourable. It was revealed that radiation, acting on the photoreceptors of a plant and thus triggering cascades of physiological and biochemical processes, can cause its ambiguous reaction. The practical significance of the results obtained was shown.

Electrically-Induced Light Emission in Polymer-Stabilized Proton Gradient Systems

2019 ◽  
Author(s):  
Jerzy J. Langer ◽  
Ewelina Frąckowiak
Keyword(s):  
Light Emission ◽  
Light Emitting Diode ◽  
Proton Gradient ◽  
Light Emitting ◽  
New Device ◽  
Polymeric Scaffold ◽  
Proton Current ◽  
The Stability ◽  
Polymer Stabilized

<div>Experiments with the chemically generated proton gradient, have lead to fabricate the system which emits the light, when electrically powered, owing to proton current flow. A polymeric scaffold preserves the stability of the system and, at the same time is playing a role of dopants of water, due to chemical character (acidic or basic) of side groups, which are responsible for gradient formation. The</div><div>results of experiments with the chemical model of the proton gradient, the protonic p-n junction, as a light emitting diode, make a “proof of concept”, which opens the way into new light generating process and new device (protonic LED), but also, to general understanding the proton gradient role in</div><div>the light emission processes.</div>

Photoluminescence and electroluminescence of mono- and dialkyl-substituted soluble polythiophenes

e-Polymers ◽  
2002 ◽  
Vol 2 (1) ◽  
Author(s):  
Luigi Angiolini ◽  
Elisabetta Salatelli ◽  
Alberto Bolognesi ◽  
Chiara Botta
Keyword(s):  
Optical Properties ◽  
Light Emitting Diode ◽  
Structural Parameters ◽  
Single Layer ◽  
Side Chains ◽  
Light Emitting ◽  
Active Film

AbstractWe report a comparison between optical properties (photoluminescence and UV-Vis absorption) and electroluminescence in a series of soluble polyalkylthiophenes with the aim of better understanding the role of different structural parameters, viz. length of side chains and introduction of unsubstituted thiophenes and their position in the backbone, on the electro-optical properties. The potential of these polymers as material for an active film in a single layer light emitting diode is evaluated.

Subjectivity of Lighting Perception and Comfort: The Role of Preferences and Expectations

2016 ◽  
Vol 49 (10) ◽  
pp. 1105-1127 ◽  
Author(s):  
Julia Maier ◽  
Oliver Zierke ◽  
Hans-Juergen Hoermann ◽  
Ivan Windemut
Keyword(s):  
Light Emitting Diode ◽  
Light Emitting ◽  
Organic Light Emitting Diode ◽  
Individual Preferences ◽  
Passenger Rail ◽  
Lighting Conditions ◽  
Organic Light ◽  
Independent Variable ◽  
Research And Design

Lighting in passenger rail cars is designed according to defined standards to implement a safe and healthy as well as comfortable lighting situation for the passengers. However, not every passenger’s demands are met by average lighting conditions; individual preferences are well-known to influence participants’ comfort sensations. To further explain the role of individual preferences and expectations regarded as stable dispositions, sensations of 40 participants were analyzed in a mock-up of a passenger rail car of the Next Generation Train (NGT) using an organic light-emitting diode (OLED) luminaire. Two lighting scenarios (100 lx and 150 lx) were used as levels of the independent variable. Results confirm that individual preferences and expectations have an influence on the perception and evaluation of the lighting situation. Moreover, positive expectations were found to have a somewhat higher impact for subjective reactions than illuminance had and should thus be considered in future lighting research and design.

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