DISCOVERY OF A NEW CLASS OF CORONAL STRUCTURES IN WHITE LIGHT ECLIPSE IMAGES

2014 ◽  
Vol 785 (1) ◽  
pp. 14 ◽  
Author(s):  
Miloslav Druckmüller ◽  
Shadia Rifai Habbal ◽  
Huw Morgan
Keyword(s):  
White Light ◽  
New Class ◽  
Coronal Structures

White-Light Coronal Structures: Streamers and CMEs

1994 ◽  
Vol 144 ◽  
pp. 82
Author(s):  
E. Hildner
Keyword(s):  
Emission Line ◽  
Electron Density ◽  
White Light ◽  
Coronal Mass Ejections ◽  
X Rays ◽  
Solar Cycles ◽  
Temperature Function ◽  
X Ray ◽  
Eclipse Observations ◽  
Coronal Structures

AbstractOver the last twenty years, orbiting coronagraphs have vastly increased the amount of observational material for the whitelight corona. Spanning almost two solar cycles, and augmented by ground-based K-coronameter, emission-line, and eclipse observations, these data allow us to assess,inter alia: the typical and atypical behavior of the corona; how the corona evolves on time scales from minutes to a decade; and (in some respects) the relation between photospheric, coronal, and interplanetary features. This talk will review recent results on these three topics. A remark or two will attempt to relate the whitelight corona between 1.5 and 6 R⊙to the corona seen at lower altitudes in soft X-rays (e.g., with Yohkoh). The whitelight emission depends only on integrated electron density independent of temperature, whereas the soft X-ray emission depends upon the integral of electron density squared times a temperature function. The properties of coronal mass ejections (CMEs) will be reviewed briefly and their relationships to other solar and interplanetary phenomena will be noted.

Periodic Variations in the Coronal Green Line Intensity and their Connection with the White-light Coronal Structures

2000 ◽  
Vol 179 ◽  
pp. 197-200
Author(s):  
Milan Minarovjech ◽  
Milan Rybanský ◽  
Vojtech Rušin
Keyword(s):  
Time Resolution ◽  
White Light ◽  
Short Time Scale ◽  
High Time Resolution ◽  
Green Line ◽  
Periodic Intensity ◽  
Coronal Green Line ◽  
Significant Intensity ◽  
Short Time ◽  
Coronal Structures

AbstractWe present an analysis of short time-scale intensity variations in the coronal green line as obtained with high time resolution observations. The observed data can be divided into two groups. The first one shows periodic intensity variations with a period of 5 min. the second one does not show any significant intensity variations. We studied the relation between regions of coronal intensity oscillations and the shape of white-light coronal structures. We found that the coronal green-line oscillations occur mainly in regions where open white-light coronal structures are located.

scholarly journals Nanophosphors-Based White Light Sources

Nanomaterials ◽  
2019 ◽  
Vol 9 (7) ◽  
pp. 1048 ◽  
Author(s):  
Maura Cesaria ◽  
Baldassare Di Bartolo
Keyword(s):  
Rare Earth ◽  
White Light ◽  
Volume Ratio ◽  
Light Sources ◽  
Co Doping ◽  
New Class ◽  
Luminescence Efficiency ◽  
Metal Doped ◽  
The Individual ◽  
The Impact

Miniaturization requests and progress in nanofabrication are prompting worldwide interest in nanophosphors as white-emission mercury-free lighting sources. By comparison with their bulk counterparts, nanophosphors exhibit reduced concentration quenching effects and a great potential to enhance luminescence efficiency and tunability. In this paper, the physics of the nanophoshors is overviewed with a focus on the impact of spatial confinement and surface-to-volume ratio on the luminescence issue, as well as rare earth-activated multicolor emission for white light (WL) output. In this respect, the prominently practiced strategies to achieve WL emission are single nanophosphors directly yielding WL by means of co-doping and superposition of the individual red, green, and blue emissions from different nanophosphors. Recently, a new class of efficient broadband WL emitting nanophosphors has been proposed, i.e., nominally un-doped rare earth free oxide (yttrium oxide, Y2O3) nanopowders and Cr transition metal-doped garnet nanocrystals. In regard to this unconventional WL emission, the main points are: it is strictly a nanoscale phenomenon, the presence of an emitting center may favor WL emission without being necessary for observing it, and, its inherent origin is still unknown. A comparison between such an unconventional WL emission and the existing literature is presented to point out its novelty and superior lighting performances.

Tunable ultra-uniform Cs4PbBr6 perovskites with efficient photoluminescence and excellent stability for high-performance white light-emitting diodes

2021 ◽  
Author(s):  
Yao Li ◽  
Kaimin Du ◽  
Manli Zhang ◽  
Xuan Gao ◽  
Yu Lu ◽  
...  
Keyword(s):  
White Light ◽  
High Performance ◽  
Light Emitting Diodes ◽  
Metal Halide ◽  
Light Emitting ◽  
New Class ◽  
Halide Perovskites ◽  
White Light Emitting Diodes ◽  
Lead Halide ◽  
Excellent Stability

Metal halide perovskites are a new class of promising materials in optoelectronic applications. As optoelectronic properties of the lead halide perovskites are determined largely by their morphology, the morphology of...

Photoluminescence studies on LiNa5(PO4)2:Dy3+, Sm3+ phosphor

2021 ◽  
Vol 0 (0) ◽  
Author(s):  
Miyapuram Ravi ◽  
Ghanta Pushpa Chakrapani ◽  
Mandava Balachandrika ◽  
Pavuluri Vasudevarao ◽  
Chendela Nageswararao ◽  
...  
Keyword(s):  
White Light ◽  
X Ray Diffraction ◽  
Light Emitting ◽  
New Class ◽  
Light Region ◽  
Crystalline Nature ◽  
Photoluminescence Studies ◽  
White Light Emitting Diodes ◽  
Good Agreement ◽  
Pure White

Abstract This paper describes the preparation, structure and photoluminescence properties of a new class LiNa5(PO4)2:Dy3+, Sm3+-phosphor. Crystalline nature confirmed by X-ray diffraction. The phases obtained are in good agreement with the standard phase. Excitation dependence and concentration effect on luminescence features are investigated. Color purity and optical bandgap are also estimated for the LiNa5(PO4)2:Dy3+, Sm3+ phosphors. The result shows LiNa5(PO4)2:Dy3+, Sm3+-phosphor excited by 374 nm nUV light produces pure white light than others. Admixing of 4f configurations and energy transfer between dopants are identified while varying the concentration of Sm3+. The CIE coordinates for LiNa5(PO4)2:0.05Dy3+, 0.05Sm3+ (x = 0.309, y = 0.332) are positioned well in white light region and very close to pure white light. The present study on LiNa5(PO4)2:Dy3+, Sm3+-phosphor suggests that it is useful for the fabrication of white light emitting diodes.

Simulating White Light Images of Coronal Structures for WISPR/Parker Solar Probe: Effects of the Near-Sun Elliptical Orbit

Solar Physics ◽  
2019 ◽  
Vol 294 (7) ◽  
Author(s):  
P. Liewer ◽  
A. Vourlidas ◽  
A. Thernisien ◽  
J. Qiu ◽  
P. Penteado ◽  
...  
Keyword(s):  
White Light ◽  
Elliptical Orbit ◽  
Coronal Structures

scholarly journals Simulating White-Light Images of Coronal Structures for Parker Solar Probe/WISPR: Study of the Total Brightness Profiles

Solar Physics ◽  
2020 ◽  
Vol 295 (4) ◽  
Author(s):  
Giuseppe Nisticò ◽  
Volker Bothmer ◽  
Angelos Vourlidas ◽  
Paulett C. Liewer ◽  
Arnaud F. Thernisien ◽  
...  
Keyword(s):  
White Light ◽  
Coronal Structures

scholarly journals The White-Light, Far-Red (600-700 nm) and Emission Coronae at the July 11, 1991 Eclipse

1994 ◽  
Vol 154 ◽  
pp. 211-215
Author(s):  
V. Rušin ◽  
M. Rybanský ◽  
M Minarovjech ◽  
T. Pintér
Keyword(s):  
White Light ◽  
Light Emission ◽  
Scattered Light ◽  
White Light Emission ◽  
Small Scale ◽  
Preliminary Results ◽  
Scale Structures ◽  
Small Scale Structures ◽  
Coronal Structures ◽  
Multiwavelength Observations

Preliminary results of the analysis of the white-light, emission (green and red), and far red (600-700 nm) corona during the July 11, 1991 eclipse are given. Even though the corona is of nearly-maximum type, four different principal coronal structures are seen, combined with faint, small-scale structures (loops, arches, cavities, voids or plasmoids). Scattered light is seen up to 10 R⊙ in helmet streamers. The Ludendorff index of the corona shape turns out to be a + b = −0.02, and the estimated brightness of JK = 1.47 × 10–6B⊙. Some aspects of multiwavelength observations are discussed.

White luminescent single-crystalline chlorinated graphene quantum dots

2020 ◽  
Vol 5 (6) ◽  
pp. 928-933 ◽  
Author(s):  
Weitao Li ◽  
Huazhang Guo ◽  
Gao Li ◽  
Zhen Chi ◽  
Hailong Chen ◽  
...  
Keyword(s):  
Quantum Dots ◽  
White Light ◽  
Graphene Quantum Dots ◽  
Luminescent Materials ◽  
Single Crystalline ◽  
Light Emitting ◽  
New Class ◽  
Potential Applications

A new class of white luminescent materials, white-light-emitting graphene quantum dots (WGQDs), have attracted increasing attention because of their unique features and potential applications.

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