yellow region
Recently Published Documents


TOTAL DOCUMENTS

32
(FIVE YEARS 9)

H-INDEX

6
(FIVE YEARS 1)

Author(s):  
V.G. Shevchuk ◽  
N.I. Poletaev ◽  
А.V. Nimich ◽  
G.L. Shyngarov

In this work we studied the emission spectra of the combustion products of low-volume dust clouds (V = 5 L) from aluminum (ASD-4), as well as clouds from mixed compositions of aluminum with inorganic powdery oxidizing agents (NaNO3, NaCl, Na2CO3·10H2O, Sr(NO3)2, Ba(NO3)2, KNO3, CuSO4, CuSO4·10H2O) and combustible (B, AlB2, Cu). This article discusses the possibilities of purposeful modification of the emission spectrum of the base composition using various inert and optically active dispersed additives that shift the maximum of the emission spectrum of the fuel composition to the region of longer waves or cause a local change in the emission spectrum in the corresponding spectral regions. In the course of the experiments, it was revealed that the introduction of additives into the basic composition of dispersed fuel does not significantly change the dynamic characteristics of the suspension. However, the additives lead to a decrease in temperature (by about 100–200°K in the presence of an additive up to 25% by weight) and to a corresponding shift in the maximum of the radiation spectrum. The possibility of a significant local modification of the spectrum in the yellow region with the help of inorganic additives to the fuel of sodium salts with a low decomposition temperature (additives Na2CO3·10H2O) was shown experimentally. Boron additives and boron compounds (B, AlB2) leads to a significant increase in the luminosity of the flame in the green region of the spectrum with a maximum radiation in the range Δλ = 530 ÷ 580 nm. The article presents the lighting characteristics (luminous intensity, light sum) of large clouds (V ≥ 10 m3) of mixed compositions based on PAP-2 aluminum powder. It was found that the introduction of inorganic additives to the base fuel does not lead to a noticeable change in the lighting characteristics, but somewhat increases the time of the cloud glow both in the visible and infrared parts of the spectrum.


2021 ◽  
Vol 1039 ◽  
pp. 382-390
Author(s):  
Arej Kadhim ◽  
Mustafa Kadhim ◽  
Haslan Abu Hassan

In this research, Zn1-xCdxSe alloys (x from 0 to 1) were synthesized by solid-state microwave (SSM) method of producing thermally evaporated thin films. The cubic structure and the elemental ratios of the films were studied using X-ray diffraction, scanning electron microscopy, and energy dispersive X-ray spectroscopy. The optical characterizations of the as-deposited film in terms of the energy band gap (Eg), photoluminescence (PL), and Raman shift spectra were conducted at the room temperature. The Eg values for the thin films from ZnSe to CdSe were 3.4 to 1.7 eV, respectively. The PL orange emission for ZnSe thin film at 565 nm, whereas 590 nm in the yellow region for CdSe thin film. From Raman shift spectra, the two longitudinal-optical phonon modes (1LO and 2LO) at 240, and 490 cm-1 are assigned for the ZnSe and CdSe thin films.


Author(s):  
Yuya Oyama ◽  
Masashi Mamada ◽  
Akihiro Kondo ◽  
Chihaya Adachi

Organic laser dyes exhibiting very low amplified spontaneous emission (ASE) thresholds in green and yellow region were developed based on a stilbene structure which is often used for the blue...


2021 ◽  
Vol 7 (2) ◽  
pp. eabd6475
Author(s):  
Shinichi Yoda ◽  
Kousuke Sakakura ◽  
Tasuku Kitamura ◽  
Yûsuke KonDo ◽  
Kazuki Sato ◽  
...  

In a Batesian mimic butterfly Papilio polytes, mimetic females resemble an unpalatable model, Pachliopta aristolochiae, but exhibit a different color pattern from nonmimetic females and males. In particular, the pale-yellow region on hind wings, which correspondingly sends important putative signals for mimicry and mate preference, is different in shape and chemical features between nonmimetic and mimetic morphs. Recently, we found that mimetic-type doublesex [dsx (H)] causes mimetic traits; however, the control of dimorphic pale-yellow colors remains unclear. Here, we revealed that dsx (H) switched the pale-yellow colors from UV-excited fluorescent type (nonmimetic) to UV-reflecting type (mimetic), by repressing the papiliochrome II synthesis genes and nanostructural changes in wing scales. Photoreceptor reactivities showed that some birds and butterflies could effectively recognize mimetic and nonmimetic pale-yellow colors, suggesting that a genetic switch in the UV response of pale-yellow colors may play essential roles in establishing the dimorphic female-limited Batesian mimicry.


Processes ◽  
2020 ◽  
Vol 9 (1) ◽  
pp. 49
Author(s):  
Thomas Nigl ◽  
Mirjam Baldauf ◽  
Michael Hohenberger ◽  
Roland Pomberger

Increasing occurrences of waste fires that are caused by improperly discarded lithium-based portable batteries threaten the whole waste management sector in numerous countries. Studies showed that high quantities of these batteries have been found in several municipal solid waste streams in recent years in Austria. This article reveals the main influence factors on the risk of lithium-based batteries in their end-of-life and it focuses on the quantification of damages to portable batteries during waste treatment processes. Hazards are identified and analysed and potential risks in waste management systems are comprehensively assessed. In two scenarios, the results showed that the potential risks are too high to maintain a sustainable form of waste management. According to the assessment, a small fire in a collection vehicle is located in the risk graph’s yellow region (as low as reasonably practicable, ALARP), while a fully developed fire in a treatment plant has to be classified as an unacceptable risk (red region of risk graph). Finally, basic recommendations for action were made.


2020 ◽  
Vol 1 (1) ◽  
pp. 11-15
Author(s):  
A. S. Dalhatu ◽  
R. Hussin ◽  
B. Ibrahim ◽  
Y. A. Yamusa ◽  
A. Baballe

Several studies showed the interesting properties of trivalent lanthanide ions when doped in various types of phosphor. Magnesium sulfoborate phosphor doped with different concentrations of Dy3+ were synthesized using solid-state reaction method at 850 °C for 4 hours. The samples were characterized by X-ray Diffraction (XRD). The excitation and luminescence properties of MgO-SO4-B2O3:Dy3+ were determined. The emission spectrum of Dy3+ ion doped MgO-SO4-B2O3 phosphor exhibit three bands at 480 nm, 573 nm and 660 nm with excitation of 386 nm due to 4F9/2 →6H15/2, 6H13/2 and 6H11/2 of Dy3+ transitions, respectively. The excitation spectrum of Dy3+ ion doped MgO-SO4-B2O3 phosphor display several bands at 347 nm, 362 nm, 386 nm, 426 nm, 449 nm and 469 nm with emission of 573 nm, which is in agreement with the ultraviolet LED (349.9–410 nm) and blue LED (450–470 nm). An intense in the emission peak at 573 nm in the yellow region was observed with the 0.5 Dy2O3. The luminescence properties of phosphor show that MgO-SO4-B2O3:Dy3+ phosphor could be potentially used as white LEDs. Dalhatu, A. S. | Department of Physics, Bauchi State University Nigeria, 65 Gadau, Bauchi, Nigeria


2019 ◽  
Vol 12 (05) ◽  
pp. 1950072
Author(s):  
Shubhra Mishra ◽  
D. S. Kshatri

Undoped and Dy[Formula: see text]-doped SrS nano-powders were synthesized by a solid-state diffusion method (SSDM). The nano-powders are then examined by the use of characterization tools as X-ray diffraction (XRD), field emission scanning electron microscopy (FESEM) and high resolution transmission electron microscopy (HRTEM) including selected area electron diffraction (SAED). The emission spectra of SrS: Dy[Formula: see text] powders are composed of a broadband and the characteristic emission of Dy[Formula: see text] peaking at 482[Formula: see text]nm (blue region), 581[Formula: see text]nm (yellow region), 676[Formula: see text]nm (light red region) and 750[Formula: see text]nm (dark red region) bands corresponding to the transitions of 4F[Formula: see text]-6H[Formula: see text], 4F[Formula: see text]-6H[Formula: see text], 4F[Formula: see text]-6H[Formula: see text] and 4F[Formula: see text]-6H[Formula: see text], respectively. The resultant nano-powders can be used to fabricate thin films for the applications of efficient optoelectronic devices.


2019 ◽  
Vol 116 (14) ◽  
pp. 6884-6890 ◽  
Author(s):  
Masafumi Inaba ◽  
Ting-Xin Jiang ◽  
Ya-Chen Liang ◽  
Stephanie Tsai ◽  
Yung-Chih Lai ◽  
...  

Animal skin pigment patterns are excellent models to study the mechanism of biological self-organization. Theoretical approaches developed mathematical models of pigment patterning and molecular genetics have brought progress; however, the responsible cellular mechanism is not fully understood. One long unsolved controversy is whether the patterning information is autonomously determined by melanocytes or nonautonomously determined from the environment. Here, we transplanted purified melanocytes and demonstrated that melanocytes could form periodic pigment patterns cell autonomously. Results of heterospecific transplantation among quail strains are consistent with this finding. Further, we observe that developing melanocytes directly connect with each other via filopodia to form a network in culture and in vivo. This melanocyte network is reminiscent of zebrafish pigment cell networks, where connexin is implicated in stripe formation via genetic studies. Indeed, we foundconnexin40(cx40) present on developing melanocytes in birds. Stripe patterns can form in quail skin explant cultures. Several calcium channel modulators can enhance or suppress pigmentation globally, but a gap junction inhibitor can change stripe patterning. Most interestingly, in ovo, misexpression of dominant negativecx40expands the black region, while overexpression ofcx40expands the yellow region. Subsequently, melanocytes instruct adjacent dermal cells to express agouti signaling protein (ASIP), the regulatory factor for pigment switching, which promotes pheomelanin production. Thus, we demonstrate Japanese quail melanocytes have an autonomous periodic patterning role during body pigment stripe formation. We also show dermal agouti stripes and how the coupling of melanocytes with dermal cells may confer stable and distinct pigment stripe patterns.


Microscopy ◽  
2019 ◽  
Vol 68 (4) ◽  
pp. 289-300
Author(s):  
Monalisa Mishra ◽  
Varsha Rathore ◽  
Swetapadma Sahu ◽  
Harekrushna sahoo

Abstract Polyphenism, an adaptation to survive throughout the year, is shown by many butterflies including Catopsilia pomona. With the variation of seasons, different morphs were found. Among all the morphs, lime exists throughout the year whereas the yellow one is available only in the winter season. The current study deciphers the colouration mechanism of yellow morph using various microscopic and spectroscopic techniques. The scanning electron microscopy analysis reveals various types of scales on the dorsal as well as the ventral side. The shape of the cover scale varies from region to region. The fine structural arrangement of the scale like window, ridge, microrib, crossrib and pigments vary throughout the wing. The pigment present in the wing is pterin as evidenced from the shape and its isolation technique. Absorption spectroscopy further confirms the presence of various types of pterin within the wing. Scanning electron microscopy discloses the dense amount of pigments within the wing. The fine structural arrangement of the wing of yellow C. pomona is compared with the yellow region of the lime C. pomona. All together, the current study describes the fine structural arrangement of the wing of yellow C. pomona and the various types of pterin which contribute towards the wing colouration. The advantage of yellow morph over lime is also discussed in this paper.


2018 ◽  
Vol 5 (7) ◽  
pp. 172010 ◽  
Author(s):  
Jonathan E. Barnsley ◽  
Elliot J. Tay ◽  
Keith C. Gordon ◽  
Daniel B. Thomas

Variation in animal coloration is often viewed as the result of chemically distinct pigments conferring different hues. The role of molecular environment on hue tends to be overlooked as analyses are mostly performed on free pigments extracted from the integument. Here we analysed psittacofulvin pigments within parrot feathers to explore whether the in situ organization of pigments may have an effect on hue. Resonance Raman spectra from a red region of a yellow-naped amazon Amazona auropalliata tail feather show frequency dispersion, a phenomenon that is related to the presence of a range of molecular conformations (and multiple chromophores) in the pigment, whereas spectra from a yellow region on the same feather do not show the same evidence for multiple chromophores. Our findings are consistent with non-isomeric psittacofulvin pigments behaving as a single chromophore in yellow feather barbs, which implies that psittacofulvins are dispersed into a structurally disordered mixture in yellow feathers compared with red feathers. Frequency dispersion in red barbs may instead indicate that pigments are structurally organized through molecule–molecule interactions. Major differences in the hues of parrot feathers are thus associated with differences in the organization of pigments within feathers.


Sign in / Sign up

Export Citation Format

Share Document