scholarly journals IMAGING DIAGNOSTICS OF COMBUSTION INSTABILITY IN PREMIXED SWIRLING COMBUSTION

2020 ◽  
Vol 4 ◽  
pp. 80-93
Author(s):  
Yao Yang ◽  
Gaofeng Wang ◽  
Yuanqi Fang ◽  
YIfan Xia ◽  
Liang Zhong
Keyword(s):  
Visible Light ◽  
Near Infrared ◽  
Combustion Instability ◽  
Infrared Light ◽  
Imaging Method ◽  
Near Infrared Light ◽  
Stable Combustion ◽  
Significant Difference ◽  
Unstable Combustion ◽  
Swirling Flames

An experimental study on combustion instability is presented with focus on propane-air premixed swirling flames. Swirling flames under self-excited oscillation are studied by imaging of visible light and OH* chemiluminescence filter under several typical conditions. The dynamical characteristics of swirling flames were analysed by Dynamic Mode Decomposition (DMD) method. Three types of unstable modes in the combustor system were observed, which correspond to typical acoustic resonant modes (LF mode, C1/4 mode and P1/2 mode) of the combustor system. The combustion instability is in the longitudinal mode. Furthermore, the structure of downstream hot burnt gas under stable combustion and unstable combustion is studied by imaging of visible light and near-infrared light. Results show that there is a significant difference in the downstream flow under stable combustion and unstable combustion. The DMD spectrum of the flame and the downstream hot burnt gas obtained is the same, which is close to the characteristic frequency of acoustic pressure captured by the microphone signal. The visible light and near-infrared light imaging observation method adopted in this paper provides a new imaging method for the investigation of thermo-acoustic instability.

scholarly journals Effects of Linear-Polarized Near-Infrared Light Irradiation on Chronic Pain

2012 ◽  
Vol 2012 ◽  
pp. 1-4 ◽  
Author(s):  
Dong Huang ◽  
Yong-Hong Gu ◽  
Qin Liao ◽  
Xue-Bin Yan ◽  
Shai-Hong Zhu ◽  
...  
Keyword(s):  
Chronic Pain ◽  
Pain Intensity ◽  
Near Infrared ◽  
Light Irradiation ◽  
Pain Clinic ◽  
Infrared Light ◽  
Controlled Study ◽  
Near Infrared Light ◽  
Group I ◽  
Significant Difference

In order to study the efficacy of linear-polarized near-infrared light irradiation (LPNIR) on relieving chronic pain in conjunction with nerve block (NB) or local block (LB), a 3-week prospective, randomized, double-blind, controlled study was conducted to evaluate the pre- and post-therapy pain intensity. Visual analogue scales (VASs) were measured in all patients before and 6 months after therapy visiting the pain clinic during the period of August 2007 to January 2008. A total of 52 patients with either shoulder periarthritis or myofascial pain syndrome or lateral epicondylitis were randomly assigned into two groups by drawing lots. Patients in Group I were treated with NB or LB plus LPNIR; Group II patients, for their part, were treated with the same procedures as in Group I, but not using LPNIR. In both groups, the pain intensity (VAS score) decreased significantly immediately after therapy as compared to therapy. There was a significant difference between the test and control groups immediately after therapy (P<0.05), while no effect 6 months later. No side effects were observed. It is concluded that LPNIR is an effective and safe modality to treat various chronic pains, which has synergic effects with NB or LB.

Detection of Wavelength in the Range from Ultraviolet to Near Infrared Light Using Two Parallel PtSe2/Thin Si Schottky Junctions

2021 ◽  
Author(s):  
Wenhua Yang ◽  
Xinyuan Jiang ◽  
Yutian Xiao ◽  
Can Fu ◽  
Jiankun Wan ◽  
...  
Keyword(s):  
Visible Light ◽  
Image Recognition ◽  
Medical Diagnosis ◽  
Near Infrared ◽  
Visible Light Communication ◽  
Optoelectronic Device ◽  
Infrared Light ◽  
Sensitive Detector ◽  
Near Infrared Light ◽  
Schottky Junctions

Wavelength sensor as a representative optoelectronic device plays an important role in many fields including visible light communication, medical diagnosis, and image recognition. Herein, a wavelength-sensitive detector with a new...

scholarly journals Near-infrared light harvesting of upconverting NaYF4:Yb3+/Er3+-based amorphous silicon solar cells investigated by an optical filter

2018 ◽  
Vol 9 ◽  
pp. 2788-2793 ◽  
Author(s):  
Daiming Liu ◽  
Qingkang Wang ◽  
Qing Wang
Keyword(s):  
Solar Cells ◽  
Visible Light ◽  
Amorphous Silicon ◽  
Near Infrared ◽  
Light Harvesting ◽  
Optical Filter ◽  
Solar Irradiation ◽  
Infrared Light ◽  
Near Infrared Light ◽  
Pmma Layer

The wastage of near-infrared light seriously restricts the photoelectric conversion efficiency of hydrogenated amorphous silicon (a-Si:H) thin film solar cells. Spectral upconversion is of great significance in reducing the wastage. Herein, the upconverting compound NaYF4:Yb3+/Er3+ was synthesized via a hydrothermal method. SEM and XRD results revealed the morphology and a phase transition from cubic to hexagonal NaYF4. Photoluminescence spectra indicated that the hexagonal NaYF4:Yb3+/Er3+ nanorods convert near-infrared light of 980 nm to the visible light with wavelength peaks at 654, 541 and 522 nm. Hence, the upconverting rods were incorporated in a polymethylmethacrylate (PMMA) layer on the rear side of a-Si:H solar cell. Under AM1.5 solar irradiation, a facile optical filter was used to scrutinize the effect of upconversion on the cell performance. Compared with a bare cell, the NaYF4:Yb3+/Er3+-based a-Si:H cell exhibited an 25% improved short-circuit current and an appreciable improvement of the near-infrared response of the external quantum efficiency. Moreover, because the size of the nanorods is comparable to the wavelength of visible light, the rods effectively scattered light, thus enhancing the visible light harvesting.

Using low-energy near infrared light and upconverting nanoparticles to trigger photoreactions within supramolecular assemblies

2016 ◽  
Vol 52 (56) ◽  
pp. 8636-8644 ◽  
Author(s):  
Tuoqi Wu ◽  
Neil R. Branda
Keyword(s):  
Visible Light ◽  
Near Infrared ◽  
High Energy ◽  
Photochemical Reactions ◽  
Supramolecular Assemblies ◽  
Supramolecular Structures ◽  
Low Energy ◽  
Infrared Light ◽  
Near Infrared Light ◽  
Trivalent Lanthanide

This overview highlights how the high-energy ultraviolet or visible light required to drive photochemical reactions can be overcome by integrating the chromophores into supramolecular structures containing upconverting nanoparticles with trivalent lanthanide dopants (such as Tm3+ and Er3+).

scholarly journals Upconversion in photodynamic therapy: plumbing the depths

2018 ◽  
Vol 47 (26) ◽  
pp. 8571-8580 ◽  
Author(s):  
Michael R. Hamblin
Keyword(s):  
Photodynamic Therapy ◽  
Transition Metal ◽  
Visible Light ◽  
Metal Nanoparticles ◽  
Near Infrared ◽  
Infrared Light ◽  
Multiphoton Absorption ◽  
Near Infrared Light ◽  
Transition Metal Nanoparticles

Upconversion photodynamic therapy uses sequential multiphoton absorption by transition metal nanoparticles (NaYF4/Yb3+/Er3+) to allow FRET excitation of traditional visible light-absorbing photosensitizers by deeply penetrating near infrared light (810 nm or 980 nm).

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