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31.
A novel method to map high dynamic range scenes to low dynamic range images utilizing the concept of color characterization,
enhancement, and balancing is described in this letter. Each pixel of the image is first characterized by extracting the relationship
of the red, green, and blue components along with its corresponding neighbors using a nonlinear line attractor network to
form an associative memory. Then, the illumination enhancement process is performed using a hyperbolic tangent function to
provide dynamic range compression to each pixel in the image. The slope of the hyperbolic tangent function is controlled using
a parameter that is determined by the local and global statistics of the image to facilitate the change of the intensity level.
A color balancing process restores the original color characteristics of the image based on learned associative memory matrices
which eliminate image distortion due to improper recombination of red, green and blue components after enhancement. Experiments
conducted on images captured at extremely uneven lighting environments show that the proposed method outperforms other image
enhancement algorithms. 相似文献
32.
The electron spin resonance spectrum of the nitroxide label 2,2,6,6 – TetraMethyl – 4 – Piperidone – Oxide (TEMPO) has been investigated in aqueous solutions of a purified and commercially available impure samples of sodium lauryl sulphate (NaLS) for a wide range of concentrations. The spectra were recorded at 24°C as a function of surfactant concentration. The reorientational correlation times Tθ of the TEMPO label in aqueous solutions were calculated using the Kivelson's theory. Using the Tθ data qualitative analysis has been carried out in an attempt to understand the microscopic effects produced by the hydrophobic part of the surfactant on the water structure and the hydrophobic-hydrophobic interactions in water. Four major discontinuities in the τθ results have been identified with the purified NaLS system. They are found to occur at NaLS concentrations of 0.008 wt.%, 0.015 wt.%, 0.23 and 1.73 wt.%. The latter two concentrations represent the first and the second critical micelle concentration (CMC) of the surfactant while the first two concentrations reveal the existence of premicellar association and dissociation processes, respectively. These discontinuities have been also confirmed by the pH data and by surface tension results from the du Noüy ring method. The effect of addition of lauryl alcohol and sodium chloride on τθ values was also studied. The additive action has been found to produce an additional discontinuity, corresponding to the mixture CMC, in the τθ versus concentration plot. Analysis of other effects such as solution aging and hydrolysis of NaLS are also included. The applicability of the spin labelling technique for the study of aqueous solution behavior of NaLS is discussed by comparing data reported in the literature. 相似文献
33.
An extracellular lipase derived from Bacillus circulans, isolated from marine macroalga, Turbinaraia conoides, was used to prepare n-3 polyunsaturated fatty acid (PUFA) concentrates from sardine oil triglycerides. The enzyme was purified 132-fold with specific activity of 386 LU/mg. The purified lipase was able to enrich sardine oil with 37.7 ± 1.98% 20:5n-3 and 5.11 ± 0.14% 18:3n-3 in the triglyceride fraction after 3 h of hydrolysis. Lower hydrophobic constants of n-3 fatty acids (18:3n-3logP = 5.65; 20:5n-3logP = 5.85, respectively) than n-6 (20:4n-6logP = 6.16) resulted in higher hydrolytic resistance of the former toward lipase, leading to their enrichment in the triglyceride fraction. Lipase-catalysed hydrolysis of sardine oil for 3 h, followed by urea complexation, provided free fatty acids containing 51.3 ± 4.65% 20:5n-3. The purified methyl ester of 20:5n-3 (68.29 ± 2.15%) from the urea concentrate was attained by chromatography on argentated neutral alumina. 相似文献
34.
Direct incorporation of vanadium into three-dimensional KIT-6: 1. Optimization of synthesis conditions 总被引:1,自引:0,他引:1
Balasamy Rabindran Jermy Sang-Yun Kim Kanattukara Vijayan Bineesh Manickam Selvaraj Dae-Won Park 《Korean Journal of Chemical Engineering》2009,26(5):1235-1240
Three dimensional (3-D) cubic KIT-6 with directly incorporated vanadium was hydrothermally synthesized by using Pluronic P123
and n-butanol as the structure-directing mixture, tetraethyl orthosilicate (TEOS) as the silica source and NH4VO3 as the vanadium source. The molar composition was varied in the range of 0.017 P123/0.08–2.4 V/1.0–2.0 TEOS/1.31–1.70 BuOH/1.83–3.00
HCl/195 H2O. The orderness of mesopore structure was estimated by X-ray diffraction, N2 adsorption, and TEM analysis. The effects of the amount of HCl, TEOS and BuOH on the structure of KIT-6 were discussed. The
time and temperature for the synthesis of KIT-6 were also optimized. The amount of vanadium content influenced the framework
structure and crystallinity of the Ia3d phase significantly. 相似文献
35.
Balasamy Rabindran Jermy Sang-Yun Kim Kanattukara Vijayan Bineesh Manickam Selvaraj Seung-Kug Song Jong-Woo Ryu Dae-Won Park 《Korean Journal of Chemical Engineering》2009,26(5):1241-1245
The direct incorporation of vanadium into the three-dimensional (3-D) cubic Ia3d mesostructure designated as V-KIT-6 was prepared,
and the material obtained therein showed a very high specific surface area of ∼1,000 m2/g with tunable pore diameters in a narrow distribution of sizes, ∼5.7 to 6.0 nm. The coordination and nature of the V sites
in V-KIT-6 were characterized by 51V-spin-echo NMR analysis. It shows that after calcination, the V4+ species are totally oxidized to the V5+ state with 4- and 6-coordinated V-O environments in a highly dispersed state with much less crystalline V2O5 formation. The calcined V-KIT-6 materials showed excellent catalytic activity in the direct oxidation of styrene using tert-butyl
hydroperoxide (TBHP) as an oxidant. 相似文献
36.
Amanat Ali Elizabeth K. M. Johnstone Bincy Baby Heng B. See Angela Song K. Johan Rosengren Kevin D. G. Pfleger Mohammed Akli Ayoub Ranjit Vijayan 《International journal of molecular sciences》2021,22(1)
Hemorphins are known for their role in the control of blood pressure. Recently, we revealed the positive modulation of the angiotensin II (AngII) type 1 receptor (AT1R) by LVV-hemorphin-7 (LVV-H7) in human embryonic kidney (HEK293) cells. Here, we examined the molecular binding behavior of LVV-H7 on AT1R and its effect on AngII binding using a nanoluciferase-based bioluminescence resonance energy transfer (NanoBRET) assay in HEK293FT cells, as well as molecular docking and molecular dynamics (MD) studies. Saturation and real-time kinetics supported the positive effect of LVV-H7 on the binding of AngII. While the competitive antagonist olmesartan competed with AngII binding, LVV-H7 slightly, but significantly, decreased AngII’s kD by 2.6 fold with no effect on its Bmax. Molecular docking and MD simulations indicated that the binding of LVV-H7 in the intracellular region of AT1R allosterically potentiates AngII binding. LVV-H7 targets residues on intracellular loops 2 and 3 of AT1R, which are known binding sites of allosteric modulators in other GPCRs. Our data demonstrate the allosteric effect of LVV-H7 on AngII binding, which is consistent with the positive modulation of AT1R activity and signaling previously reported. This further supports the pharmacological targeting of AT1R by hemorphins, with implications in vascular and renal physiology. 相似文献
37.
38.
A current transformer (CT)-based sensor has been developed to detect poor discharge conditions in copper vapour laser. The optoelectronic-based pulsed current sensor architecture involves the optical transmitter–receiver HFBR, high-frequency current transformer, and fiber optic link. The CT has been designed and calibrated to ensure generation of an optical signal at the current threshold crossover. Bandwidth analysis of the CT is carried out using the bode plot. The optoelectronic inter-conversion of the pulsed voltage of the CT and transmission via fiber optic link provides the non-contact current sensing and remote signal processing of the signal. This study discusses the details of the sensor. 相似文献
39.
A simple technique is presented to obtain normalized photoacoustic (PA) spectra corrected for the spectral variation of the source in a single scan. The input light beam is passed through the center of a dual slot chopper, which splits it into two chopped output beams at two different frequencies at a fixed ratio. The beams fall on the sample and the reference kept side-by-side in the same sample chamber. The PA signals are detected by a microphone and processed by two lock-in amplifiers tuned at two different frequencies. The technique is tested by recording the PA spectra of standard samples. 相似文献
40.
K S Divy Athulya K Madhu T U Umadevi T Suprabh P. Radhakrishnan Nair Suresh Mathew 《半导体学报》2017,38(6):063002-8
In this paper an improvement in the photocatalytic performance of TiO2 was carried out via hybridizing with graphene. Graphene-TiO2 (GR-TiO2)nanocomposites with different weight addition ratios of graphene oxide (GO) have been prepared via a facile microwave irradiation of GO and tetrabutyl titanate in isopropyl alcohol. Raman spectroscopy (RS), X-ray diffraction (XRD), scanning electron microscopy (SEM), transmission electron microscopy (TEM), UV-visible spectroscopy (UV-vis), Fourier transform infrared spectra (FTIR), energy dispersive X-ray spectroscopy (EDX) and photoluminescence spectra (PL) are employed to determine the properties of the samples. Microwave irradiation can heat the reactant to a higher temperature in a short time, simultaneously GO is reduced to graphene and TiO2 nanoparticles grown on the surface of GR. GR-TiO2 nanocomposites synthesized via this approach have efficient electron conductivity in GR, resulting in a reduced electron-hole recombination rate. Among the synthesized nanocomposites, GT-8wt% exhibited the best photocatalytic activity toward photocatalytic degradation of MB. Our current work provides a new insight for the fabrication of GR-TiO2 nanocomposites within a short reaction time and also explains the mechanism of photocatalysis employing radical and hole scavengers. 相似文献