scholarly journals High Stability LED-Pumped Nd:YVO4 Laser with a Cr:YAG for Passive Q-Switching

Crystals ◽  
2019 ◽  
Vol 9 (4) ◽  
pp. 201
Author(s):  
Xiao ◽  
Zhao ◽  
Ge ◽  
Zhong ◽  
Li ◽  
...  
Keyword(s):  
Peak Power ◽  
High Stability ◽  
Continuous Wave ◽  
Light Emitting Diode ◽  
Pump Energy ◽  
Optical Conversion Efficiency ◽  
Sharp Decline ◽  
Light Emitting ◽  
Q Switching ◽  
The Cost

With improvements in light-emitting diode (LED) performance and a sharp decline in price, a light source with the irradiance of a laser and the cost of an LED is worthy of further study. We demonstrated a LED-pumped Nd:YVO4 laser in quasi-continuous-wave (QCW) and passively Q-switched (PQS) regime. With an incident pump energy of 6.28 mJ (150 μs pulses at 1 Hz), the Nd:YVO4 laser has an energy of 206 μJ at 1064 nm in the QCW regime. The optical conversion efficiency of the system is 4.1%, and the slope efficiency is 9.0%. A pulsed energy of 2.5 μJ was obtained with a duration of 897 ns (FWHM) in the PQS regime, which means the peak power is 2.79 W. The output energy stability is 97.54%.

scholarly journals Methods of Disinfecting Stethoscopes: Systematic Review

2020 ◽  
Vol 17 (6) ◽  
pp. 1856 ◽  
Author(s):  
Margherita Napolitani ◽  
Daiana Bezzini ◽  
Fulvio Moirano ◽  
Corrado Bedogni ◽  
Gabriele Messina
Keyword(s):  
Systematic Review ◽  
English Language ◽  
Light Emitting Diode ◽  
Bacterial Load ◽  
Silver Ions ◽  
Light Emitting ◽  
Disinfection Methods ◽  
Mesh Terms ◽  
Healthcare Associated ◽  
The Cost

The aim of this systematic review was to investigate the effectiveness of various disinfection methods available for stethoscopes. In March 2019, we performed a search in PubMed and Scopus using the search terms: “reducing stethoscopes contamination” and “disinfection stethoscopes”; the Mesh terms used in PubMed were “Decontamination/methods” or “Disinfection/methods” and “Stethoscopes/microbiology”. Selection criteria were: English language; at least one disinfection method tested. A total of 253 publications were screened. After title, abstract, and full-text analysis, 17 papers were included in the systematic review. Ethanol at 90%, Ethanol-Based Hands Sanitizer (EBHS), triclosan, chlorhexidine, isopropyl alcohol, 66% ethyl alcohol, sodium hypochlorite, and benzalkonium chloride have been proven to lower the presence of bacteria on stethoscopes’ surfaces. In addition, alcohol wipes show effective results. A wearable device emitting ultraviolet C by Light-Emitting Diode (LED) resulted efficacious against common microorganisms involved in Healthcare Associated Infections. The cover impregnated with silver ions seemed to be associated with significantly higher colony counts. Instead, copper stethoscopes surface reduced bacterial load. The disinfection of stethoscopes appears to be essential. There are many valid methods available; the choice depends on various factors, such as the cost, availability, and practicality.

1.331μm Narrow-Bandwidth Light Source Based on Polymer Micro-Blazed Grating

2008 ◽  
Author(s):  
Hairong Wang ◽  
Xianni Gao ◽  
Guoliang Sun ◽  
Yulong Zhao ◽  
Zhuangde Jiang
Keyword(s):  
Light Source ◽  
Light Emitting Diode ◽  
Low Cost ◽  
Diffraction Order ◽  
Blazed Grating ◽  
Light Emitting ◽  
Led Light ◽  
Narrow Bandwidth ◽  
Narrow Width ◽  
The Cost

In order to detect methane (CH4) accurately and reliably, this paper presents a sensor which consists of infrared diode, fixtures, blazed grating, to realize the extremely narrow-bandwidth light at wavelength of 1.331μm. Based on factors such as compatibility with the transmission characteristics of silica fiber and the cost, a LED (light-emitting diode) with center wavelength of 1.3μm is selected. The LED light is modulated as the parallel light beam. As the light is incident in a micro-blazed grating with certain angle, by diffraction and interference, the light will output the maximum light intensity of its diffraction order at 1.331 μm, which just is an absorption peak of CH4. Micro-blazed grating applied here is low cost and easy replication by various ways, which makes extreme narrow width wavelength possible. Simulation and analysis indicate the designed prototype can output 1.331μm with bandwidth from 1.32907μm to 1.332495μm. With the light source basing on light dividing system, more reliable and higher sensitive measurement of the dangerous gases such as methane and carbon monoxide (CO) can be realized.

Thermal Performance of Domestic Replacement A19 LED Lighting Products

2016 ◽  
Author(s):  
Thomas Storey ◽  
Robin Rackerby ◽  
Heather Dillon ◽  
Lydia Gingerich
Keyword(s):  
Heat Exchanger ◽  
Thermal Performance ◽  
Heat Dissipation ◽  
Cooling System ◽  
Light Emitting Diode ◽  
Research Process ◽  
Light Emitting ◽  
Led Lighting ◽  
Proper Design ◽  
The Cost

In an effort to create a Light Emitting Diode (LED) lighting system that is as efficient as possible, the heat dissipation system must be accurately measured for proper design and operation. Because LED lighting technology is new, little optimization has been performed on typical cooling system required for most A19 replacement products. This paper describes the research process for evaluating the thermal performance of over 15 LED lighting products and compares their performance to traditional lighting sources, namely incandescent and compact fluorescent (CFL). This process uses radiation and convection to model typical cooling mechanisms for domestic A19 type replacement LED products. The A19 products selected for this investigation had input wattages ranging between 7 to 60 Watts, with outputs ranging from 450 to 1100 lumens. The average LED tested dissipated 43% (± 5%) of the total heat generated in the lighting product through the heat exchanger. The best thermal performance was observed in an LED product that dissipated approximately 58% of the total product heat through the heat exchanger. Results indicate that significant improvements to the current LED heat exchanger designs are possible, which will help lower the cost of future LED products, improve performance, and reduce the environmental footprint of the products.

High stability white organic light-emitting diode fabricated with the deposition of solvent premixed sources

2011 ◽  
Vol 131 (10) ◽  
pp. 2106-2109 ◽  
Author(s):  
Su-Hua Yang ◽  
Shih-Fong Huang ◽  
Chien-Hua Chang ◽  
Chi-Hung Chung
Keyword(s):  
High Stability ◽  
Light Emitting Diode ◽  
Light Emitting ◽  
Organic Light Emitting Diode ◽  
Organic Light

Short-Coherence Light Source Digital Holography Imaging Using Light-Emitting Diodes

2013 ◽  
Vol 718-720 ◽  
pp. 2281-2285
Author(s):  
Pu Hui Meng ◽  
Da Yong Wang ◽  
Yun Xin Wang
Keyword(s):  
Light Source ◽  
Digital Holography ◽  
Light Emitting Diode ◽  
Phase Image ◽  
Light Emitting ◽  
Intensity Images ◽  
Different Depths ◽  
Phase Shifting Method ◽  
The Cost ◽  
Gating Effect

Light-emitting diode (LED) is a kind of short-coherence light source, and it can generate time gating effect and reduce the speckle noises in digital holography. Meanwhile, it can cut down the cost of the setup since LED is cheaper than laser. In this paper, an in-line digital holography setup was designed with LED, and the holograms were reconstructed by four-step phase shifting method. Comparing with the phase image obtained by the laser-based setup, results show that the phase image of USAF test target possesses lower speckle noises with the help of LED. Finally, we reconstruct a series of intensity images with different depths of a coin, and these images are fused to get a synthesized image with more information.

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