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排序方式: 共有513条查询结果,搜索用时 570 毫秒
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Marcos Eduardo Valle Raul Ambrozio Valente 《Journal of Mathematical Imaging and Vision》2017,57(2):183-201
Mathematical morphology is a theory with applications in image processing and analysis. This paper presents a quantale-based approach to color morphology based on the CIELab color space in spherical coordinates. The novel morphological operations take into account the perceptual difference between color elements by using a distance-based ordering scheme. Furthermore, the novel approach allows for the use of non-flat structuring elements. An illustrative example reveals that non-flat dilations and erosions may preserve more features of a color image than their corresponding flat operations. Furthermore, the novel non-flat morphological operators yielded promising results on experiments concerning the detection of the boundaries of objects on color images. 相似文献
24.
Comprehensive design schemes and specifications have progressively shaped Master-Planned Communities (MPCs). The market largely predetermines these outcomes, with background input from communities. Therefore, this paper endeavours to define the fundamental structures that generate differences between market actors and residents within the North Lakes MPC. This study employs ‘habitus theory’, which is a sociological phenomenon describing the divergence of personal outlooks and expertise. The application of this theory is thus illustrative of the evolution of distinct observations within MPCs. Contemporary studies have under-researched these inherent gaps between communities, authorities, and critics, and these frictions could be exacerbated within restrictive developmental contexts. Epistemic and objectified content analyses collated over many years and sources will uncover the underlying differences between the relevant groups. These analyses will enable the progression of a framework for understanding power relation biases and how reflexivity can enhance current consultative methods. 相似文献
25.
Summary
Novel hyperbranched amino-terminated polyglycidoles have been synthesized and tested as macromolecular ligands in the oxidative
coupling reaction of phenylacetylene. Amino-terminated polyglycidoles-CuCl complexes showed to be more effective catalysts
than the reference monomeric tertiary amines-CuCl ones, but less effective than the most efficient N,N,N'N'-tetramethylethylenediamine-(TMDA)
CuCl complex. The difference in performance of monomeric and hyperbranched ligands is probably due to two factors. The first
one is better complexation abilities and the second is the local increase of reagent concentration.
Received: 28 April 2001/Revised version: 29 August 2001/Accepted: 5 September 2001 相似文献
26.
Emmanuel Vázquez-Mayorga ángel G. Díaz-Sánchez Ruben K. Dagda Carlos A. Domínguez-Solís Raul Y. Dagda Cynthia K. Coronado-Ramírez Alejandro Martínez-Martínez 《International journal of molecular sciences》2016,17(8)
Mutations the in human DJ-1 (hDJ-1) gene are associated with early-onset autosomal recessive forms of Parkinson’s disease (PD). hDJ-1/parkinsonism associated deglycase (PARK7) is a cytoprotective multi-functional protein that contains a conserved cysteine-protease domain. Given that cysteine-proteases can act on both amide and ester substrates, we surmised that hDJ-1 possessed cysteine-mediated esterase activity. To test this hypothesis, hDJ-1 was overexpressed, purified and tested for activity towards 4-nitrophenyl acetate (pNPA) as µmol of pNPA hydrolyzed/min/mg·protein (U/mg protein). hDJ-1 showed maximum reaction velocity esterase activity (Vmax = 235.10 ± 12.00 U/mg protein), with a sigmoidal fit (S0.5 = 0.55 ± 0.040 mM) and apparent positive cooperativity (Hill coefficient of 2.05 ± 0.28). A PD-associated mutant of DJ-1 (M26I) lacked activity. Unlike its protease activity which is inactivated by reactive oxygen species (ROS), esterase activity of hDJ-1 is enhanced upon exposure to low concentrations of hydrogen peroxide (<10 µM) and plateaus at elevated concentrations (>100 µM) suggesting that its activity is resistant to oxidative stress. Esterase activity of DJ-1 requires oxidation of catalytic cysteines, as chemically protecting cysteines blocked its activity whereas an oxido-mimetic mutant of DJ-1 (C106D) exhibited robust esterase activity. Molecular docking studies suggest that C106 and L126 within its catalytic site interact with esterase substrates. Overall, our data show that hDJ-1 contains intrinsic redox-sensitive esterase activity that is abolished in a PD-associated mutant form of the hDJ-1 protein. 相似文献
27.
Francisco Payri Jose Vicente Pastor Raul Payri Julien Manin 《Journal of Mechanical Science and Technology》2011,25(1):209-219
The optical depth is responsible of limiting the optical diagnostic using visible wavelength in the sprays. This paper proposes
to measure the optical depth directly in a real Diesel spray through line-of-sight laser extinction measurements. This easily
reproducible method which does not require expensive or complex optical techniques is detailed and the measurement procedure
is presented in this paper. As diesel sprays are mostly optically thick, the measurements in the denser region are not reliable
and a fuel concentration model has been used to derive the results to the entire spray. This work provides values of SMD at
different distance from the nozzle tip depending on the specific parameters like injection pressure or discharge density.
The values extracted from a combined experimental/computational approach have been compared to PDPA measurements under the
same testing conditions. The results have shown that the maximum optical depth was higher than 10 and that an increase of
the injection pressure led to higher τ values. The SMD values appeared to be below the results measured by the PDPA and the
droplet diameter showed to be the main responsible of the optical depth of the jet under the tested conditions. 相似文献
28.
Matthieu Picher Hugo Navas Raul Arenal Etienne Quesnel Eric Anglaret Vincent Jourdain 《Carbon》2012,50(7):2407-2416
The influence of the temperature and precursor pressure on the defect density of single-walled carbon nanotubes (SWCNTs) grown by catalytic chemical vapor deposition was studied for several catalyst–precursor couples. The SWCNT defect density was assessed by studying the Raman D band. In situ Raman monitoring was used to determine experimental conditions allowing the preparation of samples free of pyrolytic carbon and not altered by air exposure. The most striking feature is that the Arrhenius plots of the IG/ID ratio systematically display a convex shape, i.e. the apparent activation energy decreases with increasing temperature. From HRTEM observations and oxidation experiments, this evolution of the D band features is ascribed to the catalytic growth of long SWCNTs with few defects at high temperature and of short and defective SWCNTs and carbon structures at low temperature. The convex Arrhenius behavior is well accounted by two kinetic models: (i) a model considering a change of intermediate states as a function of the temperature (for instance due to a phase transition of the catalyst particle or a change of intermediate carbon species) and (ii) a model considering a high-temperature process of defect creation (for instance by reaction with reactive gas species). 相似文献
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30.
Vicente Pacheco Raul Cardoso-Gil Lorenzo Tepech-Carrillo Yuri Grin 《Corrosion Science》2011,(7):2368-2373
The corrosion of thermoelectric clathrates α- and β-Eu8Ga16−xGe30+x is studied under static air (DSC/TG) up to 650 °C. Oxidation product layers with thicknesses of 10.5 μm (α-Eu8Ga16−xGe30+x) and 4.5 μm (β-Eu8Ga16−xGe30+x) are formed. The oxidation begins at 360 and 380 °C, respectively. XRD pattern of the β-Eu8Ga16−xGe30+x oxidized layer shows Ge and four Eu2O3 reflections; while α-Eu8Ga16−xGe30+x data (sample crushed and grinded) shows α-Eu8Ga16−xGe30+x reflections (majority phase), two EuGa2±xGe4?x strongest reflections and Ge (minority phases). These results indicate the amount of oxides is very small or they are amorphous. High temperature powder XRD measurements on α-Eu8Ga16−xGe30+x under air confirm the oxidation onset temperature determined in DSC studies. 相似文献