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61.
A two-stage method for the reconstruction of missing data in the transmission of baseline JPEG coded images in error prone environments is proposed. In the first stage, we estimate the values of the missing DC coefficients. As effects of errors in estimating the missing DC values will appear as a number of stripes across the image, a technique for removing such stripes is also developed. In the second stage, the data of missing blocks is reconstructed by exploiting the correlation between adjacent blocks. Simulation results intricate that our reconstruction method performs very well. The two key contributions of our method are that it does not assume nondifferential encoding of the DC coefficients, and that it performs well in the reconstruction of diagonal edges. 相似文献
62.
Regina Krachler Rudolf F. Krachler Altan Süphandag Shahram Ayromlou Bernhard K. Keppler 《The Science of the total environment》2010,408(11):2402-9557
Peat bogs have the ability to produce strong chelate ligands (humic and fulvic acids) which enhance the weathering rates of iron-silicate minerals and greatly increase the solubility of the essential trace metal iron in river water. Fluvial networks link peat bogs with the ocean, and thus terrestrial-derived fulvic-iron complexes fuel the ocean's biological productivity and biological carbon pump, but understanding this role is constrained by inconsistent observations regarding the behaviour of riverine iron in the estuarine mixing zone, where precipitation reactions remove iron from the water column. We applied a characterization of the colloidal iron carriers in peatland-draining rivers in North Scotland, using field-flow fractionation (FFF), in combination with end-member mixing experiments of river water sampled near the river mouth and coastal seawater using a 59Fe radiotracer method. According to our results, the investigated river contributed “truly dissolved” Fe concentrations of about 3300 nmol L− 1 to the ocean which is nearly two orders of magnitude higher than the dissolved iron contribution of the “average world” river (∼ 40 nmol L− 1). Thus we conclude that peatland-draining rivers are important sources of dissolved iron to the ocean margins. We propose highly electrostatic and sterical stabilized iron-organic matter complexes in the size range of < 2 kDa to be responsible for iron transport across the estuarine mixing zone. 相似文献
63.
ZnO nanoparticles have been prepared successfully by hydrogel decomposition method (HDM). Synthesized ZnO nanoparticles were characterized by X‐ray diffraction (XRD), fourier transforms infrared spectroscopy (FTIR), and transition electron microscopy (TEM) techniques. Narrow distribution of sizes with a 20–30 nm diameter and regular distribution of ZnO nanoparticles are attributed to the application of poly(acrylic acid‐co‐acrylamide) grafted chitosan hydrogel as coating agent. The results show that the polymer thermal decomposition technique is a perfect method for the synthesis of ZnO nanoparticles. © 2010 Wiley Periodicals, Inc. J Appl Polym Sci, 2010 相似文献
64.
Mahdi Pourafshari Chenar Houman Savoji Mohammad Soltanieh Takeshi Matsuura Shahram Tabe 《Korean Journal of Chemical Engineering》2010,27(6):1876-1881
Impurities such as hydrogen sulfide, water vapor and heavy hydrocarbons in natural gas have considerable effects on the membrane
performance. Small amounts of condensable and polymer soluble components in the feed gas cause swelling or plasticization
of glassy membranes, leading to a reduction in membrane selectivity. In the present research the influence of ethane was investigated
on the permeance and selectivity of two commercially available hollow fiber membranes, namely Cardo-type polyimide and PPO
hollow fibers for CO2/CH4 separations. It was concluded that the gas mixture permeation rate was increased in the presence of C2H6. However, the CO2/CH4 separation factors remained almost the same in the presence and absence of the C2H6. 相似文献
65.
Majid Moghadam Valiollah Mirkhani Shahram Tangestaninejad Iraj Mohammadpoor-Baltork Maedeh Moshref Javadi 《Inorganic chemistry communications》2010,13(2):244-249
The hybrid complex consist of molybdenylacetylacetonate complex covalently linked to a lacunary Keggin-type polyoxometalate, K8[SiW11O39] (POM), was synthesized and characterized by elemental analysis, SEM, XRD, diffuse reflectance UV–Vis and FT-IR spectroscopic methods. The hybrid complex, [MoO2(acac)–POM] (1), was used for alkene epoxidation with tert-BuOOH in 1,2-dichloroethane as solvent. The complex (1) can catalyze epoxidation of various olefins including non-activated terminal olefins. The effect of reaction parameters such as oxidant, solvent, and temperature on the epoxidation of cyclooctene was also investigated. This heterogeneous catalyst was reused several times in the oxidation of cyclooctene. 相似文献
66.
In this paper, the compensation advantage of the first-generation current conveyor (CCI) over the second-generation current
conveyor (CCII) in tunable circuits is shown. For this purpose, a new floating frequency dependent negative resistor (FDNR)
simulator using three CCIs is presented and employed in a third-order high-pass filter. The compensation feature of the CCI
is shown for the proposed high-pass filter. As a second example, the presented compensation method is tested in a second-order
band-pass filter constructed with two CCIs. Applying the proposed compensation technique, the CCI-based circuits can operate
in lower biasing currents, which result in lower power consumption. 相似文献
67.
Shahram Minaei Guven Topcu Oğuzhan Çiçekoğlu 《International Journal of Electronics》2013,100(9):581-588
In this paper new active only current-mode integrator and differentiator with electronically tunable time constants are described. They are composed of one operational amplifier (OA) and two operational transconductance amplifiers (OTAs), and are suitable for monolithic implementation either with CMOS or bipolar technologies. No realizability conditions are imposed for the proposed circuits and all of the active sensitivities are low. The performances of the circuits are demonstrated on the PSPICE platform. 相似文献
68.
Shahram Emami Venkatesh Meda Robert T. Tyler 《International Journal of Food Science & Technology》2011,46(2):421-428
The effect of micronisation (high‐intensity infrared heating) and microwave radiation of normal barley (NB), high‐amylose barley (HAB) and waxy barley (WB) on the physical and mechanical properties was studied. Samples were tempered to 42–45% moisture content and then subjected to infrared or microwave radiation to reduce the moisture content to approximately 10%. The grain surface temperature during radiation was maintained at 100 °C. The changes in physical and mechanical properties were compared with unprocessed samples. Thermal radiation increased slightly the volume of the kernels because of the diffusion of water vapour from inside to the outer surface. These changes resulted in a decrease in particle and bulk densities. Thermal radiation affected the Hunter colour values, as well. The mechanical properties including bio‐yield point, modulus of elasticity and breakage susceptibility were affected by micronisation and microwave heating. 相似文献
69.
70.