Chromatic refraction in the lower atmosphere associated with refractive index gradient features

2019 ◽  
Author(s):  
Mohammad Abdullah-Al-Mamun ◽  
David Voelz
Keyword(s):  
Refractive Index ◽  
Lower Atmosphere ◽  
Refractive Index Gradient ◽  
Index Gradient

scholarly journals Comparisons between high-resolution profiles of squared refractive index gradient <i>M</i><sup>2</sup> measured by the Middle and Upper Atmosphere Radar and unmanned aerial vehicles (UAVs) during the Shigaraki UAV-Radar Experiment 2015 campaign

2017 ◽  
Vol 35 (3) ◽  
pp. 423-441 ◽  
Author(s):  
Hubert Luce ◽  
Lakshmi Kantha ◽  
Hiroyuki Hashiguchi ◽  
Dale Lawrence ◽  
Masanori Yabuki ◽  
...  
Keyword(s):  
Refractive Index ◽  
Convective Cloud ◽  
Upper Atmosphere ◽  
Refractive Index Gradient ◽  
Very High Frequency ◽  
Range Resolution ◽  
Mu Radar ◽  
Radar Echo ◽  
Index Gradient ◽  
Complex Features

Abstract. New comparisons between the square of the generalized potential refractive index gradient M2, estimated from the very high-frequency (VHF) Middle and Upper Atmosphere (MU) Radar, located at Shigaraki, Japan, and unmanned aerial vehicle (UAV) measurements are presented. These comparisons were performed at unprecedented temporal and range resolutions (1–4 min and  ∼  20 m, respectively) in the altitude range  ∼  1.27–4.5 km from simultaneous and nearly collocated measurements made during the ShUREX (Shigaraki UAV-Radar Experiment) 2015 campaign. Seven consecutive UAV flights made during daytime on 7 June 2015 were used for this purpose. The MU Radar was operated in range imaging mode for improving the range resolution at vertical incidence (typically a few tens of meters). The proportionality of the radar echo power to M2 is reported for the first time at such high time and range resolutions for stratified conditions for which Fresnel scatter or a reflection mechanism is expected. In more complex features obtained for a range of turbulent layers generated by shear instabilities or associated with convective cloud cells, M2 estimated from UAV data does not reproduce observed radar echo power profiles. Proposed interpretations of this discrepancy are presented.

scholarly journals Label-Free Digital Holo-tomographic Microscopy Reveals Virus-Induced Cytopathic Effects in Live Cells

mSphere ◽  
2018 ◽  
Vol 3 (6) ◽  
Author(s):  
Artur Yakimovich ◽  
Robert Witte ◽  
Vardan Andriasyan ◽  
Fanny Georgi ◽  
Urs F. Greber
Keyword(s):  
Refractive Index ◽  
Vaccinia Virus ◽  
Virus Type ◽  
Live Cells ◽  
Refractive Index Gradient ◽  
Label Free ◽  
Virus Infections ◽  
Cytopathic Effects ◽  
Infected Cells ◽  
Index Gradient

ABSTRACTCytopathic effects (CPEs) are a hallmark of infections. CPEs are difficult to observe due to phototoxicity from classical light microscopy. We report distinct patterns of virus infections in live cells using digital holo-tomographic microscopy (DHTM). DHTM is label-free and records the phase shift of low-energy light passing through the specimen on a transparent surface with minimal perturbation. DHTM measures the refractive index (RI) and computes the refractive index gradient (RIG), unveiling optical heterogeneity in cells. We find that vaccinia virus (VACV), herpes simplex virus (HSV), and rhinovirus (RV) infections progressively and distinctly increased RIG. VACV infection, but not HSV and RV infections, induced oscillations of cell volume, while all three viruses altered cytoplasmic membrane dynamics and induced apoptotic features akin to those caused by the chemical compound staurosporine. In sum, we introduce DHTM for quantitative label-free microscopy in infection research and uncover virus type-specific changes and CPE in living cells with minimal interference.IMPORTANCEThis study introduces label-free digital holo-tomographic microscopy (DHTM) and refractive index gradient (RIG) measurements of live, virus-infected cells. We use DHTM to describe virus type-specific cytopathic effects, including cyclic volume changes of vaccinia virus infections, and cytoplasmic condensations in herpesvirus and rhinovirus infections, distinct from apoptotic cells. This work shows for the first time that DHTM is suitable to observe virus-infected cells and distinguishes virus type-specific signatures under noninvasive conditions. It provides a basis for future studies, where correlative fluorescence microscopy of cell and virus structures annotate distinct RIG values derived from DHTM.

Diffusion coefficient measurement in a microfluidic analyzer using dual-beam microscale-refractive index gradient detection

2003 ◽  
Vol 1013 (1-2) ◽  
pp. 77-91 ◽  
Author(s):  
Colin D. Costin ◽  
Roy K. Olund ◽  
Bethany A. Staggemeier ◽  
Ana Kristine Torgerson ◽  
Robert E. Synovec
Keyword(s):  
Refractive Index ◽  
Diffusion Coefficient ◽  
Refractive Index Gradient ◽  
Dual Beam ◽  
Coefficient Measurement ◽  
Index Gradient

Investigation on the Reversed Spin Hall Effect of Light Caused by the Refractive-Index Gradient

2012 ◽  
Vol 32 (8) ◽  
pp. 0826001
Author(s):  
赵桂平 Zhao Guiping ◽  
周新星 Zhou Xinxing ◽  
李瑛 Li Ying ◽  
罗海陆 Luo Hailu ◽  
文双春 Wen Shuangchun
Keyword(s):  
Refractive Index ◽  
Hall Effect ◽  
Spin Hall Effect ◽  
Refractive Index Gradient ◽  
Index Gradient ◽  
Effect Of Light
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