Polymer-derived preparations of the blue-excited greenish-yellow-emitting calcium-containing β-Si3N4:Eu-like phosphors

2021 ◽  
Vol 47 (11) ◽  
pp. 15415-15423
Author(s):  
Yaomin Deng ◽  
Huifang Xu ◽  
Xuan Cheng ◽  
Ying Zhang ◽  
Jingyu Sun ◽  
...  
Keyword(s):  
Greenish Yellow

Arrheniusite-(Ce), CaMg[(Ce7Y3)Ca5](SiO4)3(Si3B3O18)(AsO4)(BO3)F11, a New Member of the Vicanite Group, from the Östanmossa Mine, Norberg, Sweden

2021 ◽  
Author(s):  
Dan Holtstam ◽  
Luca Bindi ◽  
Paola Bonazzi ◽  
Hans-Jürgen Förster ◽  
Ulf B. Andersson
Keyword(s):  
Structure Refinement ◽  
New Mineral ◽  
X Ray Diffraction ◽  
Unit Cell Parameters ◽  
Calculated Density ◽  
Epma Data ◽  
X Ray ◽  
Cell Parameters ◽  
Greenish Yellow ◽  
The Ideal

ABSTRACT Arrheniusite-(Ce) is a new mineral (IMA 2019-086) from the Östanmossa mine, one of the Bastnäs-type deposits in the Bergslagen ore region, Sweden. It occurs in a metasomatic F-rich skarn, associated with dolomite, tremolite, talc, magnetite, calcite, pyrite, dollaseite-(Ce), parisite-(Ce), bastnäsite-(Ce), fluorbritholite-(Ce), and gadolinite-(Nd). Arrheniusite-(Ce) forms anhedral, greenish-yellow translucent grains, exceptionally up to 0.8 mm in diameter. It is optically uniaxial (–), with ω = 1.750(5), ε = 1.725(5), and non-pleochroic in thin section. The calculated density is 4.78(1) g/cm3. Arrheniusite-(Ce) is trigonal, space group R3m, with unit-cell parameters a = 10.8082(3) Å, c = 27.5196(9) Å, and V = 2784.07(14) Å3 for Z = 3. The crystal structure was refined from X-ray diffraction data to R1 = 3.85% for 2286 observed reflections [Fo > 4σ(Fo)]. The empirical formula for the fragment used for the structural study, based on EPMA data and results from the structure refinement, is: (Ca0.65As3+0.35)Σ1(Mg0.57Fe2+0.30As5+0.10Al0.03)Σ1[(Ce2.24Nd2.13La0.86Gd0.74Sm0.71Pr0.37)Σ7.05(Y2.76Dy0.26Er0.11Tb0.08Tm0.01Ho0.04Yb0.01)Σ3.27Ca4.14]Σ14.46(SiO4)3[(Si3.26B2.74)Σ6O17.31F0.69][(As5+0.65Si0.22P0.13)Σ1O4](B0.77O3)F11; the ideal formula obtained is CaMg[(Ce7Y3)Ca5](SiO4)3(Si3B3O18)(AsO4)(BO3)F11. Arrheniusite-(Ce) belongs to the vicanite group of minerals and is distinct from other isostructural members mainly by having a Mg-dominant, octahedrally coordinated site (M6); it can be considered a Mg-As analog to hundholmenite-(Y). The threefold coordinated T5 site is partly occupied by B, like in laptevite-(Ce) and vicanite-(Ce). The mineral name honors C.A. Arrhenius (1757–1824), a Swedish officer and chemist, who first discovered gadolinite-(Y) from the famous Ytterby pegmatite quarry.

The implications of reworking on the mineralogy and chemistry of Lower Carboniferous K-bentonites

Clay Minerals ◽  
1996 ◽  
Vol 31 (3) ◽  
pp. 377-390 ◽  
Author(s):  
T. Clayton ◽  
J. E. Francis ◽  
S. J. Hillier ◽  
F. Hodson ◽  
R. A. Saunders ◽  
...  
Keyword(s):  
Trace Element ◽  
Volcanic Ash ◽  
Clay Fraction ◽  
Trace Element Content ◽  
Element Content ◽  
Heavy Minerals ◽  
Lower Carboniferous ◽  
Greenish Yellow ◽  
Trace Element Contents ◽  
Plastic Clays

AbstractPotassium-bentonites have been found in the Courceyan Lower Limestone Shales near Burrington Combe and Oakhill, Somerset, consisting of thin, greenish yellow, plastic clays interbedded within a mudrock and limestone sequence. Mineralogically, the clay fraction is composed of virtually monomineralic interstratified illite-smectite containing 7–10% smectite layers. The clay fraction of the surrounding mudrocks, however, consists of an illite-chlorite dominated assemblage. Their mineral composition, trace element content, and the relative abundance of zircon crystals suggest an origin from burial of montmorillonite originally formed from volcanic ash. The presence of anomalously high trace element contents with both euhedral and rounded zircon grains in the Oakhill K-bentonites suggests a secondary or reworked origin for these samples. In contrast, the presence of a non-anomalous trace element content and large (>100 μm) euhedral zircon grains suggests that the Burrington K-bentonite is primary in origin. Modelling of whole-rock rare-earth element (REE) patterns shows that the Oakhill REE pattern can be derived from the Burrington pattern by the addition of small contributions from zircon and monazite, two major heavy minerals present. These K-bentonites probably represent the oldest Carboniferous K-bentonites so far recorded in the British Isles.

scholarly journals Two cases of trichromic vision

1905 ◽  
Vol 76 (508) ◽  
pp. 194-198
Keyword(s):  
Simultaneous Contrast ◽  
Greenish Yellow ◽  
Orange Yellow ◽  
Different Parts

1. One case (Professor J. J. Thomson) sees only three colours in the bright spectrum—red, green, and violet. He can distinguish nothing of the nature of pure yellow, like the sensation given him by the sodium flame in the spectrum. There is no definite colour to him at the portion of the spectrum where the normal sighted see pure blue. Reddish-green would describe the orange and yellow regions and greenish-violet the blue. λ 5950 (orange-yellow) is the point which differs most from red and green. There was no shortening of either end of the spectrum. The point of junction of the red and green differed somewhat in repeating the observations because of his great sensitiveness to simultaneous contrast. It was, however, always in the orange or orange-yellow, never in the yellow of the normal sighted. Difference of Hue Perception .—I then tested him with my apparatus for ascertaining the size of different parts of the spectrum which appear monochromatic, and found that he was defective in distinguishing differences of hue. A portion of the spectrum corresponding to the D lines, and isolated by two shutters in the eye-piece of the spectroscope, was first shown. The shutter on the red side was gradually opened until a difference of hue was seen. The monochromatic patch extended from λ 5889 to λ 6052, being exactly half as large again as that of the normal sighted, which occupies the space from λ 5889 to λ 5998. The monochromatic patch the called greenish-yellow. His monochromatic patch in the centre of the green bore exactly the same proportion to mine as in the case of the orange-yellow, being just half as large again.

scholarly journals IV. On two new vanadium minerals

1877 ◽  
Vol 25 (171-178) ◽  
pp. 109-112 ◽  
Keyword(s):  
Specific Gravity ◽  
San Francisco ◽  
Vanadium Pentoxide ◽  
Gold Mine ◽  
Greenish Yellow ◽  
The Matrix

No. 1.—The first of these remarkable minerals contains 28 per cent. of vanadium pentoxide. It was forwarded to me by Dr. James Blake, of San Francisco, with the following statement:—“I discovered it in a gold-mine, and it serves as the matrix for the gold. It occurs in small bunches, filling cavities in a schistose porphyry." The mineral occurs in radiating and foliated talc-like masses, greenish grey in bulk, and light greenish yellow when seen in fragments, forming a grey powder. Its lustre is subvitreous to fatty. In mass it is opaque, but is translucent in thin splinters. Its hardness is about equal to that of talc; its specific gravity is 2·902.

scholarly journals THE WAVELENGTH SENSITIVITY FUNCTION FOR THE ZEBRA FINCH

1942 ◽  
Vol 25 (3) ◽  
pp. 381-390 ◽  
Author(s):  
W. J. Crozier ◽  
Ernst Wolf
Keyword(s):  
Zebra Finch ◽  
Relative Energy ◽  
Energy Scale ◽  
Sensitivity Function ◽  
Direct Examination ◽  
Flicker Response ◽  
Greenish Yellow ◽  
Wavelength Sensitivity ◽  
General Kind

With lights of different spectral compositions filtered from a white, the flicker response contours for the zebra finch are found to exhibit the same general kind of relationship between flicker excitation and wavelength as is found in the case of man ("cone" contours), with the same filters. The flicker contours for the zebra finch are simplex; the retina contains no rods. On a relative energy scale, with a flash cycle of fixed light-time percentage (10 per cent) the curve for yellow almost coincides with that for the white, the curve for red lies at much higher intensities, and the curves for blue-green and violet fall below that for the white by amounts increasing in that order. The maxima to which the curves rise and the slope constants are very nearly the same for all the spectral regions. For the bird the blue was a little less efficient, the green a little more efficient, and the red very much less efficient than in the case of man. It was deduced that in the retina of this diurnal bird the number of red oil globules should be comparatively small and that most of the globules should be greenish yellow. This was confirmed by direct examination.

New reddish-orange and greenish-yellow light emitting phosphors: Eu3+ and Tb3+/Eu3+ in sodium germanate glass

2014 ◽  
Vol 153 ◽  
pp. 198-202 ◽  
Author(s):  
E. Álvarez ◽  
Ma. E. Zayas ◽  
J. Alvarado-Rivera ◽  
F. Félix-Domínguez ◽  
R.P. Duarte-Zamorano ◽  
...  
Keyword(s):  
Yellow Light ◽  
Germanate Glass ◽  
Light Emitting ◽  
Greenish Yellow ◽  
Reddish Orange

A Study of the Argentaffin (Kultschitzky) Cells in frozen-dried Tissue by Phase-Contrast Microscopy and Ultra-Violet Light

1955 ◽  
Vol s3-96 (35) ◽  
pp. 289-293
Author(s):  
A. C. CHRISTIE
Keyword(s):  
Phase Contrast ◽  
Ultra Violet ◽  
Phase Contrast Microscopy ◽  
Ultra Violet Light ◽  
Violet Light ◽  
Greenish Yellow ◽  
Orange Yellow ◽  
Photographic Evidence ◽  
Absorption Of Light ◽  
Contrast Microscopy

1. The argentaffin cells in guinea-pig intestine have been studied by phase-contrast microscopy and in ultra-violet light. Frozen-dried tissue has been used. 2. One such cell in a section 5-7µ thick was selected and studied throughout. In an unfixed section mounted in nonane, the cytoplasm is packed with fine granules which emit a greenish-yellow fluorescence in ultra-violet light of wavelength 2,750 Å. There is also photographic evidence of absorption of light of this wavelength. 3. After formaldehyde fixation the fluorescence changes to orange-yellow and becomes much weaker. The absorption of light by the granular cytoplasmic contents is also greatly reduced. 4. There is no fluorescence and no photographic evidence of absorption of light of wavelength 2570 Å by the granular cytoplasmic contents, either before or after formaldehyde fixation. 5. The nuclear chromatin pattern in these cells is unaltered by formaldehyde fixation, and is well demonstrated in photographs taken in ultra-violet light of both the wavelengths mentioned above.

Sign in / Sign up

Export Citation Format

Share Document