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Abstract—This article discusses spatial brightness and visual clarity to
question whether these are similar or different phenomena of visual
perception. A review of the descriptions reported in past articles suggests
that some re...
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Abstract—This article discusses spatial brightness and visual clarity to
question whether these are similar or different phenomena of visual
perception. A review of the descriptions reported in past articles suggests
that some researchers consider spatial brightness and visual clarity to
be different, although this is not a universal opinion. In contrast, analyses
of the results of brightness and clarity judgments given by na?ve test
participants to lighting of different spectral power distribution in previous
work suggests that similar judgments are given for brightness and clarity
when the meanings of these items are undefined in the test procedure
and this is the more frequent situation. This review demonstrates the
need for care in defining and interpreting category rating scales.
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The Al coatings were electrodeposited on the Cu substrate from AlCl3-EMIC ionic liquid (AlCl3:EMIC = 2:1 molar ratio) containing three cyanopyridine additives with different positions of the substituent group on the pyridine ring,...
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The Al coatings were electrodeposited on the Cu substrate from AlCl3-EMIC ionic liquid (AlCl3:EMIC = 2:1 molar ratio) containing three cyanopyridine additives with different positions of the substituent group on the pyridine ring, which were 2-cyanopyridine, 3-cyanopyridine, and 4-cyanopyridine. The effects of cyanopyridine additives on the deposition potential, morphology, brightness, and corrosion properties of Al coatings were investigated. It was considered that the deposition potential of Al shifted to more negative overpotentials, the quality of Al coatings was promoted, and the corrosion property was improved by the cyanopyridine additives to a varying degree. Especially in the presence of 4-cyanopyridine, the flattest mirror bright Al coating was obtained, which had the smallest homogeneous nanocrystal grain size and strongest Al (200) crystallographic orientation. The average roughness Ra value was as low as 31 nm compared to that in the absence of cyanopyridine additives, which was 417 nm. Furthermore, the corrosion current density of the bright Al coating was three orders of magnitude lower than the rough Al coating, which resulted from the dense nanocrystal structure.
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IN MARCH 2007, MEMBER GOVERNMENTSof the European Union signed a bindingagreement to source 20 per cent of their energyfrom renewable resources by 2020. Whilebiofuels look set to become a popular choice offuel to help countries ach...
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IN MARCH 2007, MEMBER GOVERNMENTSof the European Union signed a bindingagreement to source 20 per cent of their energyfrom renewable resources by 2020. Whilebiofuels look set to become a popular choice offuel to help countries achieve these targets,concerns over the environmental impacts ofdedicating yet more land to agriculture mean thatwe will also need to investigate other, oldertechnologies that have yet to realise their initialpotential fully. One such technology is the solar cell. Butwhile, on the surface, it appears to be an idealsource of energy by making using of an (almost)universally available resource – the Sun – mostof us have yet to see the benefits in anything moreenergy consuming than a solar-powered hand-held calculator.
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In this Letter, a new strategy for the spectral beam com-bining (SBC) of an individual laser diode (LD) bar based on a polarization multiplexing external cavity is proposed and demonstrated. The maximum combining elficiency is up ...
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In this Letter, a new strategy for the spectral beam com-bining (SBC) of an individual laser diode (LD) bar based on a polarization multiplexing external cavity is proposed and demonstrated. The maximum combining elficiency is up to 95.51%, which leads to an output power of 76.6 W and an electro-optic conversion elficiency of 48.33% under continuous wave operation at a current of 100 A. Com-pared to the conventional SBC, the combining elficiency, the output power, and the electro-optical conversion elficiency present improvements of 12%, 10W, and 6%, respectively. The results show that this novel SBC method is a prospec-tive technique for increasing the combining elficiency of LD bars.
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The fundamental goal of color appearance research is to establish a correlation between the optical properties of stimuli and their corresponding perceptual attributes. Stimuli seen on a self-luminous background occur frequently i...
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The fundamental goal of color appearance research is to establish a correlation between the optical properties of stimuli and their corresponding perceptual attributes. Stimuli seen on a self-luminous background occur frequently in everyday situations when viewing lamps and luminaires, luminous panels with light emitting diodes (LEDs) and organic light emitting diodes (OLEDs), traffic signals, and advertisements. In this article, the impact of the luminance of a neutral self-luminous background on the brightness perception of neutral self-luminous stimuli was investigated in a series of magnitude estimation experiments. A brightness model has been developed with the spectral radiance from stimulus and background as input. The cone excitations are calculated using the CIE 2006 10 degrees cone fundamentals. Luminance adaptation to the background is included by adopting a background-dependent semisaturation constant in the Michaelis-Menten function modeling cone response compression. The performance of the model is very good if negative and positive contrast scenes are modeled independently.
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We study the “color weight” for a number of rather different paradigms. In well researched heterochromatic photometry methods we find that the “weights” determined by settings of naive observers are closely determined by the C...
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We study the “color weight” for a number of rather different paradigms. In well researched heterochromatic photometry methods we find that the “weights” determined by settings of naive observers are closely determined by the CIE luminance functional. This is very different for tasks that involve mid- and high-level aspects of perception. In several cases we find equipollence for the display red, green and blue channels. Moreover, in such cases the very nonlinear maximum-rule fits the data rather better than a linear functional. These findings are of interest when photometry needs to be applied for stimuli that are different from the high temporal and low spatial frequency gratings typical for flicker photometry. These results are relevant for science, ergonomics and art.
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The chromophore release and identification method isolates well-defined chromophoric substances from different cellulosic matrices, such as highly bleached pulps, cotton linters, bacterial cellulose, viscose or lyocell fibers, and...
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The chromophore release and identification method isolates well-defined chromophoric substances from different cellulosic matrices, such as highly bleached pulps, cotton linters, bacterial cellulose, viscose or lyocell fibers, and cellulose acetates. The chromophores are present only in extremely low (ppm to ppb) concentrations. The concept of primary and secondary chromophores is introduced, with primary chromophores arising only from the polysaccharides inherent to cellulosic materials. Secondary chromophores also include atoms from the chemicals used to process the cellulose. Most primary chromophores belong to one of three compound classes: hydroxy-[1,4]-benzoquinones, hydroxy-[1,4]-naphthoquinones, and hydroxyacetophenones. Among them, three individual compounds dominate: 2,5-dihydroxy-[1,4]-benzoquinone, 5,8-hydroxy-[1,4]-naphthoquinone, and 2,5-dihydroxyacetophenones, amounting to more than 80 % of the total isolated chromophores in most cases. In lignin-free cellulosics, these three compounds can thus be regarded as key chromophores. The prevalence of these molecules is due to both exceptionally strong resonance stabilization, as reflected in delocalized double bonds, and their ready reformation from carbohydrate degradation products by recondensation reactions. The findings that (a) most chromophores in lignin-free cellulosic materials belong to only three compound classes and that (b) three chromophore compounds make up the bulk of the chromophore mixtures are foundational for future bleaching research: Based on this knowledge, specific searches for optimized bleaching conditions can now concentrate on these compounds and still cover the vast majority of chromophores.
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Recently, research has been done from various directions to evaluate the brightness of spaces. However, no studies have been conducted regarding quantitative measurements of the brightness at different positions in a visual field....
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Recently, research has been done from various directions to evaluate the brightness of spaces. However, no studies have been conducted regarding quantitative measurements of the brightness at different positions in a visual field. That is, a model for evaluating the brightness of spaces and lighting design techniques have not been considered much regarding the brightness at different positions in the visual field. Therefore, in this study, the sensitivity to brightness at different positions in the visual field was investigated in order to quantify brightness perception throughout the entire visual field. The experimental results show the tendency for Lm/Lt rises as the visual angle increases. Moreover, they show the Lm/Lt in the vertical lower direction is higher than that in other directions, especially at 20 degrees or more.
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Stretching 134 feet long and 55 feet high and weighing 52 tons, the Scoreboard is the largest high-definition video display in the world, delivering crisp instant replays and ad messages plus game timing, player stats and, of cour...
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Stretching 134 feet long and 55 feet high and weighing 52 tons, the Scoreboard is the largest high-definition video display in the world, delivering crisp instant replays and ad messages plus game timing, player stats and, of course, animation to whip the home crowd into a frenzy. For the University of Texas at Austin, it's the crown on a $164 million face-lift to its football stadium. For Daktronics of Brookings, S.D., it meant $6 million of revenue and one of the most challenging assignments in its 38 years. The usual lag time between signed contract—in this case, May 8—and game time is 12 months. Daktronics had to be good to go in 4: Opening day for the national champion Longhorns was Sept. 2. "You have to see it to appreciate it," says Chief Executive James Morgan, 59. An understatement.
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Stretching 134 feet long and 55 feet high and weighing 52 tons, the Scoreboard is the largest high-definition video display in the world, delivering crisp instant replays and ad messages plus game timing, player stats and, of cour...
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Stretching 134 feet long and 55 feet high and weighing 52 tons, the Scoreboard is the largest high-definition video display in the world, delivering crisp instant replays and ad messages plus game timing, player stats and, of course, animation to whip the home crowd into a frenzy. For the University of Texas at Austin, it's the crown on a $164 million face-lift to its football stadium. For Daktronics of Brookings, South Dakota, it meant $6 million of revenue and one of the most challenging assignments in its 38 years. The usual lag time between signed contract—in this case, May 8—and game time is 12 months. Daktronics had to be good to go in 4: Opening day for the national champion Longhorns was Sept. 2. "You have to see it to appreciate it," says Chief Executive James Morgan, 59. An understatement.
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