scholarly journals Design of Switchable On/Off Subpixels for Primary Color Generation Based on Molybdenum Oxide Gratings

Physics ◽  
2021 ◽  
Vol 3 (3) ◽  
pp. 655-663
Author(s):  
Gonzalo Santos ◽  
Francisco González ◽  
Dolores Ortiz ◽  
José María Saiz ◽  
Maria Losurdo ◽  
...  

Structural color emerges from the interaction of light with structured matter when its dimension is comparable to the incident wavelength. The reflected color can be switched by controlling such interaction with materials whose properties can be changed through external stimuli such as electrical, optical, or thermal excitation. In this research, a molybdenum oxide (MoOx) reflective grating to get a switchable on/off subpixel is designed and analyzed. The design is based on subpixel on and off states that could be controlled through the oxidation degree of MoOx. A suitable combination of three of these subpixels, optimized to get a control of primary colors, red, green, and blue, can lead to a pixel which can cover a wide range of colors in the color space for reflective display applications.

Materials ◽  
2021 ◽  
Vol 14 (7) ◽  
pp. 1740
Author(s):  
Konrad Jakubowski ◽  
Manfred Heuberger ◽  
Rudolf Hufenus

The increasing interest in luminescent waveguides, applied as light concentrators, sensing elements, or decorative illuminating systems, is fostering efforts to further expand their functionality. Yarns and textiles based on a combination of distinct melt-spun polymer optical fibers (POFs), doped with individual luminescent dyes, can be beneficial for such applications since they enable easy tuning of the color of emitted light. Based on the energy transfer occurring between differently dyed filaments within a yarn or textile, the collective emission properties of such assemblies are adjustable over a wide range. The presented study demonstrates this effect using multicolor, meltspun, and photoluminescent POFs to measure their superimposed photoluminescent emission spectra. By varying the concentration of luminophores in yarn and fabric composition, the overall color of the resulting photoluminescent textiles can be tailored by the recapturing of light escaping from individual POFs. The ensuing color space is a mean to address the needs of specific applications, such as decorative elements and textile illumination by UV down-conversion.


1999 ◽  
Vol 09 (12) ◽  
pp. 2295-2303 ◽  
Author(s):  
S. RIPOLL MASSANÉS ◽  
C. J. PÉREZ VICENTE

We have studied the stochastic behavior of Fitzhugh–Nagumo neuron-like model (FN) induced by subthreshold external stimuli. Our analysis based on three standard measures: the power spectrum, interspike interval distribution (ISI) and autocorrelation function shows that it is possible to define a characteristic time scale which can be identified in the response of the system for a wide range of frequencies. In contrast to previous studies we have focused our attention on high frequency signals which could be of interest for real systems such as nervous fibers in the auditory system. We report behaviors which resemble those of classical deterministic oscillators but never the stochastic resonance phenomenon typical of low frequency signals.


2018 ◽  
Author(s):  
Solly Aryza

It is very challenging to recognize a face from an image due to the wide variety of face and the uncertain of face position. The research on detecting human faces in color image and in video sequence has been attracted with more and more people. In this paper, we propose a novel face detection method that achieves better detection rates. The new face detection algorithms based on skin color model in YCgCr chrominance space. Firstly, we build a skin Gaussian model in Cg-Cr color space. Secondly, a calculation of correlation coefficient is performed between the given template and the candidates. Experimental results demonstrate that our system has achieved high detection rates and low false positives over a wide range of facial variations in color, position and varying lighting conditions.


Nanophotonics ◽  
2018 ◽  
Vol 8 (2) ◽  
pp. 331-338 ◽  
Author(s):  
Tomer Lewi ◽  
Nikita A. Butakov ◽  
Jon A. Schuller

AbstractMetasurfaces exploit optical phase, amplitude, and polarization engineering at subwavelength dimensions to achieve unprecedented control of light. The realization of all dielectric metasurfaces has led to low-loss flat optical elements with functionalities that cannot be achieved with metal elements. However, to reach their ultimate potential, metasurfaces must move beyond static operation and incorporate active tunability and reconfigurable functions. The central challenge is achieving large tunability in subwavelength resonator elements, which requires large optical effects in response to external stimuli. Here we study the thermal tunability of high-index silicon and germanium semiconductor resonators over a large temperature range. We demonstrate thermal tuning of Mie resonances due to the normal positive thermo-optic effect (dn/dT>0) over a wide infrared range. We show that at higher temperatures and longer wavelengths, the sign of the thermo-optic coefficient is reversed, culminating in a negative induced index due to thermal excitation of free carriers. We also demonstrate the tuning of high-order Mie resonances by several linewidths with a temperature swing of ΔT<100 K. Finally, we exploit the large near-infrared thermo-optic coefficient in Si metasurfaces to realize optical switching and tunable metafilters.


2019 ◽  
Vol 10 (3) ◽  
pp. 13-16
Author(s):  
Sumit Maitra ◽  
Diptendu Chatterjee ◽  
Arup Ratan Bandyopadhyay

Background: Skin pigmentation is one of the most variable phenotypic traits and most noticeable of human polymorphisms. Skin pigmentation in humans is largely determined by the quantity and distribution of the pigment melanin. The literature review on skin color variation revealed a few works on skin pigmentation variation has been conducted in India from Southern, Western and Northern part. Aims and Objectives: To best of the knowledge, the present discourse is the first attempt to understand skin color variation from Eastern and North Eastern part of India among three populations. Materials and Methods: The present study consisted of 312 participants from Chakma and Tripuri groups of Tripura, North East India, and participants from Bengalee Hindu caste population from West Bengal. Skin color was measured by Konica Minolta CR-10 spectrophotometer which measures and quantifies the colors with a 3D color space (CIELAB) color space created by 3 axes. All the skin color measurements from each participant were taken from unexposed (underarm) left and right to get a mean and exposed (forehead) to sunlight. Results: The distribution of skin color variation among the three populations demonstrated significant (p<0.05) difference in lightness for unexposed and exposed indicating lightness in unexposed area. Furthermore, the present study revealed significant difference (p<0.05) in skin color among the ethnic groups across the body location and all three attributes (lightness, redness and yellowness). Conclusion: Generally, skin color variation may be elucidated by two main factors: individual differences in lightness and yellowness and by and large due to ethnicity, where diversity in redness is due to primarily due to different body locations. Variation in lightness have more characteristic probability. The present study first time reports the wide range of quantitative skin color variation among the three ethnic groups from Eastern and North East India and highest yellowness (b*) among the population from North East India.


2006 ◽  
Vol 23 (3-4) ◽  
pp. 549-554 ◽  
Author(s):  
J.D. MORELAND ◽  
S. WESTLAND

An earlier modeling study of the effect of changes in macular pigment optical density (MPOD) on a wide range of surface colors is re-examined. That study reported changes in local chromaticity variance and in color spacing, some of which were incompatible with tritan-like confusions in normals associated with high-simulated MPOD. This disagreement might have arisen through the use of the von Kries correction for adaptation. The analysis is repeated, using 1782 reflectance spectra of natural and man-made colors. These colors are segregated into an array of 25 equally populated cells in an analogue of the MacLeod-Boynton cone excitation diagram. Removing the von Kries correction restores compatibility with other experimental data. Differences between the results for normal and anomalous trichromats, noted in the earlier study, are confirmed. An analysis of local chromaticity variance across color space indicates the presence of systematic patterns. The earlier study also reported differences in results across observer types (for example, between normals and protanomals) and this is addressed here by utilizing fundamentals defined by a variable photopigment template. Chromaticities are computed for the same 1782 reflectance spectra for normals and for a set of protanomals (for whom the anomalous L pigment is shifted between the normal L and M spectral locations). Colors are segregated into an array of 100 cells in an analogue of the MacLeod-Boynton cone excitation diagram. Changes in chromaticity variance with MPOD for these cells are mapped for normals and protanomals. Variance along the L/(L + M) axis is sensitive to the number of cells used for segmentation. It also increases with MPOD for normal observers but this trend reverses as the wavelength of maximum sensitivity of the L cone shifts towards shorter wavelengths (protanomalous locations).


2008 ◽  
Vol 51 (2) ◽  
pp. 263-269 ◽  
Author(s):  
Silmara R. Bianchi ◽  
Mario Miyazawa ◽  
Edson L. de Oliveira ◽  
Marcos Antonio Pavan

The quantity of soil organic matter (SOM) was estimated through the determination of soil organic carbon (SOC) times a factor, which assumes that 58% of the SOM was formed by carbon. A number of soil samples with wide range of SOC content collected in the state of Paraná, Brazil were evaluated in the laboratory. SOC was measured by Walkley-Black method and the total SOM by loss on ignition. The SOC was positively correlated with SOM. The SOM/SOC ratio varied from 1.91 to 5.08 for the soils. It shows that Brazilian SOM has greater oxidation degree. Although, the SOM and SOC decreased with soil depth the SOM/SOC ratio increased. It showed that SOM in the subsoil contained more oxygen but less carbon than the SOM in the upper soil surface. The CEC/SOC also increased with depth indicating that the functional groups of the SOM increased per unity of carbon.


2014 ◽  
Vol 633-634 ◽  
pp. 116-119
Author(s):  
Hong Ming Wang ◽  
Xiao Jian Fan ◽  
Gui Rong Li ◽  
Wei Wen Chen ◽  
Lei Cao ◽  
...  

Based on the direct reduction alloying theory, experiments on chromium molybdenum alloy prepared through the direct reduction and alloying reactions between the high-carbon ferrochrome and molybdenum oxide were conducted in a laboratory scale. The critical factors that would impact the reduction rate of molybdenum oxide and the yield rate of molybdenum were analyzed. The results indicate that the reduction rate of molybdenum oxide can exceed 90%, meanwhile, the yield rate of molybdenum is affected by many factors and fluctuates in a wide range. As temperature rising, the reduction rate of molybdenum oxide is increased whereas the yield rate of molybdenum is decreased. With the amount of molybdenum oxide added increasing, the reduction rate of molybdenum oxide and yield rate of molybdenum are decreased simultaneously. Making slag during melting process and molybdenum oxide roasted by addition of lime are effective measures to improve the yield rate of molybdenum.


Homeopathy ◽  
2021 ◽  
Author(s):  
Raj Kumar Manchanda ◽  
Meeta Gupta ◽  
Ankit Gupta ◽  
Robbert van Haselen

Abstract Background Signaling molecules such as cytokines and interleukins are key mediators for the immune response in responding to internal or external stimuli. Homeopathically prepared signaling molecules have been used therapeutically for about five decades. However, these types of products are not available in many countries and their usage by homoeopaths is also infrequent. The aim of this scoping review is to map the available pre-clinical and clinical data related to the therapeutic use of homeopathically prepared signaling molecules. Methods We conducted a scoping review of clinical and pre-clinical studies of therapeutically used signaling molecules that have been prepared in accordance with an officially recognized homeopathic pharmacopoeia. Articles in peer-reviewed journals reporting original clinical or pre-clinical research of homeopathically prepared signaling molecules such as interleukins, cytokines, antibodies, growth factors, neuropeptides and hormones, were eligible. Non-English language papers were excluded, unless we were able to obtain an English translation. An appraisal of eligible studies took place by rating the direction of the outcomes on a five-point scale. The quality of the papers was not systematically assessed. Results Twenty-eight eligible papers, reporting findings for four different manufacturers' products, were identified and reviewed. Seventeen papers reported pre-clinical studies, and 11 reported clinical studies (six experimental, five observational). A wide range of signaling molecules, as well as normal T-cell expressed specific nucleic acids, were used. A majority of the products (21 of 28) contained two or more signaling molecules. The most common clinical indications were psoriasis, vitiligo, rheumatoid arthritis, respiratory allergies, polycystic ovary syndrome, and herpes. The direction of the outcomes was positive in 26 papers and unclear in two papers. Conclusion This scoping review found that there is a body of evidence on the use of homeopathically prepared signaling molecules. From a homeopathy perspective, these substances appear to have therapeutic potential. Further steps to explore this potential are warranted.


2020 ◽  
Vol 2020 (28) ◽  
pp. 1-6
Author(s):  
Rafał K. Mantiuk ◽  
Minjung Kim ◽  
Maliha Ashraf ◽  
Qiang Xu ◽  
M. Ronnier Luo ◽  
...  

We model color contrast sensitivity for Gabor patches as a function of spatial frequency, luminance and chromacity of the background, modulation direction in the color space and stimulus size. To fit the model parameters, we combine the data from five independent datasets, which let us make predictions for background luminance levels between 0.0002 cd/m2 and 10 000 cd/m2, and for spatial frequencies between 0.06 cpd and 32 cpd. The data are well-explained by two models: a model that encodes cone contrast and a model that encodes postreceptoral, opponent-color contrast. Our intention is to create practical models, which can well explain the detection performance for natural viewing in a wide range of conditions. As our models are fitted to the data spanning very large range of luminance, they can find applications in modeling visual performance for high dynamic range and augmented reality displays.


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