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991.
Nanotemplated materials have significant potential for applications in energy conversion and storage devices due to their unique physical properties. Nanostructured materials provide additional electrode surface area beneficial for energy conversion or storage applications with short path lengths for electronic and ionic transport and thus the possibility of higher reaction rates. We report on the use of controlled growth of metal and alloy electrodeposited templated nanostructures for energy applications. Anodic aluminium oxide templates fabricated on Si for energy materials integration with electronic devices and their use for fuel cell and battery materials deposition is discussed. Nanostructured Pt anode catalysts for methanol fuel cells are shown. Templated CuSn alloy anodes that possess high capacity retention with cycling for lithium microbattery integration are also presented. 相似文献
992.
Sayed Hasan Razi Abdi Young Jin Kim Yong-Ki Park Songhun Yoon Won Choon Choi Hee Young Kim Mijeong Han Chul Wee Lee 《Korean Journal of Chemical Engineering》2011,28(2):396-401
A simple synthesis protocol to prepare egg-like carbon-silica hybrids was developed where the size of a silica ball housed
inside a carbon shell was tunable. An egg-tray type of carbon-silica hybrid was also made by the oxidation of egg-like carbon-silica
hybrids. This oxidized hybrid has shown high ammonia adsorption capacity that is about 30 times more than the standard commercial
adsorbent H-ZSM-5 (SiO2/Al2O3=128). 相似文献
993.
Hadi AI-Saadi Reyad Al-Sayed Mohammad Al-Sheikh Hasan Hussein Al-Bahadili 《能源与动力工程:英文版》2014,(4):741-748
A PV (photovoltaic) solar panels exhibit non-linear current--voltage characteristics, and according to the MPT (maximum power transform) theory, it can produce maximum power at only one particular OP (operating point); namely, when the source impedance matches with the load impedance, a match which cannot be guaranteed spontaneously. Furthermore, the MPP (maximum power point) changes with temperature and light intensity variations. Therefore, different algorithms have been developed for finding MPPT (maximum power point tracking) based on offline and online methods. Evaluating the performance of these algorithms for various PV systems operating under highly dynamic environments are essentials to ensure producing reliable, efficient, cost-effective and high performance systems. One possible approach for system evaluation is to use computer simulation. This paper addresses the use of Matlab software as a simulation tool for evaluating the performance of PV solar systems and finding the MPPT. 相似文献
994.
995.
Hasan Ahmad Mohammad Abu‐Waesmin Mohammad Mahbubor Rahman Mohammad Abdul Jalil Miah Klaus Tauer 《应用聚合物科学杂志》2013,127(1):620-627
The application potential of hydrophobic polymer is numerous. Lauryl methacrylate (LMA) having long alkyl chain is a commercially available hydrophobic monomer. In this investigation, poly‐LMA (PLMA) latex particles were prepared by suspension polymerization in aqueous media using 2,2′‐azobis(isobutyronitrile) (AIBN) in presence of poly(vinyl alcohol) (PVA) as steric stabilizer. The preparation kinetics was studied in detail in terms of percentage yield and particle size variation. Low glass transition temperature (~ ?65°C) associated with high flexibility did not allow electron micrographic observation though 1H‐NMR and particle size measurement confirmed the formation of PLMA latex. To improve the glass transition temperature, aqueous emulsion copolymerization of LMA with methyl methacrylate (MMA) was carried out. The solubility of LMA was improved by adding ethanol to the aqueous phase. Two types of polymeric stabilizers, PVA and poly(vinyl pyrrolidone) (PVP) were used to stabilize the colloidal particles. The nature of the stabilizer affected both morphology and final rate of polymerization. The hydrophobic P(LMA‐MMA) copolymer particles were subsequently modified by nanosized magnetic (Fe3O4) particles by two different methods. The in situ formation of Fe3O4 particles in presence of P(LMA‐MMA) was found to be suitable for the preparation of magnetic latex particles. Scanning electron microscope (SEM), FTIR, transmission electron microscope (TEM), X‐ray diffraction (XRD) and energy‐dispersive X‐ray spectroscopy (EDX) were used for the characterization of magnetically doped particles. © 2012 Wiley Periodicals, Inc. J. Appl. Polym. Sci., 2013 相似文献
996.
A mathematical model was constructed and solved to quantitatively describe the dynamic behavior of the potassium sorbate diffusion through whey protein films. The model results were compared with the experimental data of the potassium sorbate diffusion through whey protein films, and excellent agreements between the experimental data and the model results are observed. The experimental data for potassium sorbate diffusion through whey protein films were used for mathematical model of potassium sorbate diffusion through whey protein films and the determination of both potassium sorbate and solvent diffusion coefficients. The diffusivities of potassium sorbate at 25°C ranged from 4.12 to 9.34 × 10?11 m2/s, while that of the solvent was between 1.38 and 8.74 × 10?10 m2/s, depending on the film composition. 相似文献
997.
In this study, grain drying in a spherical-based spouted bed (SBSB), a cone-based spouted bed (CBSB), and a paraboloid-based spouted bed (PBSB) with and without draft tube was investigated. Spouted-bed bases with the same volume in different shapes—spherical, cone, and paraboloid—were used for the drying experiments to investigate the effect of the spouted-bed base shape on drying. The drying experiments were carried out with perforated and solid draft tubes. The effects of the distance between the gas inlet nozzle and the bottom of the draft tube (entrainment zone height) and the draft tube diameter as geometric parameters on drying were also investigated. It was seen that the geometrical shape of the contactor base influenced the drying time. The highest drying rate was achieved for drying in a paraboloid-based spouted bed. The results also showed that using a draft tube caused a significant increase in drying time. Because the perforated draft tube allows a higher gas flow rate through the annulus, it decreases the drying time when compared with the solid draft tube. Drying time decreased slightly with the decreasing height of the entrainment zone but draft tube diameter did not have a considerable effect on drying. 相似文献
998.
The effects of strontium doping on the structural properties and magnetic ordering of Nd1?xSrxFeO3 orthoferrite system have been studied by employing macroscopic and microscopic structural techniques like X-ray diffraction, scanning electron microscopy and 57Fe Mössbauer spectroscopy. X-ray diffraction confirmed that single phase materials have been synthesized. It has been observed that orthorhombic distortion, density and porosity have decreased; whereas, grain size, tolerance factor and symmetry have increased with increase in the strontium concentration. Mössbauer results showed an increase in the Fe4+/Fe3+ ratio, sagging and local octahedral distortions while decrease in the magnetic ordering with increase in the strontium content. The origin behind anomalous octahedral distortions in this system has been attributed to the decrease in the oxidation state and mismatch in the ionic radii of A-site cations and increase in the concentration of Fe4+, due to Sr2+ doping at Nd3+ sites. The collapse of magnetic ordering has been ascribed to the weakening of super-exchange interactions, dilution of strong long range magnetic sub-lattice of high spin Fe3+ (five unpaired electrons) by relatively lower spin of high spin Fe4+ (four unpaired electrons) and increase in the spin–spin relaxation frequency. 相似文献
999.
Abstract Softwood species generally have been found very recalcitrant to enzymatic hydrolysis of the carbohydrate fractions to monomeric sugars. To solve this problem, loblolly pine chips were pretreated with green liquor at 12–20% Total Titratable Alkali (TTA) (as Na2O on wood) at 170°C for 800 H-factor. The yield of resulting pulp was 76.5–78.6% and the lignin content decreased from 29.2 to 20.2–22.4% and the total polysaccharide decreased from 62.6 to 53.8–55.0%, all based on the weight of original wood. When the pulp was subjected to enzymatic hydrolysis using 40 Filter Paper Unit (FPU)/g pulp, only 41% of the polysaccharides in wood were converted to monomeric sugars. This conversion figure is much lower than that of mixed southern hardwoods (80%) treated under similar conditions. If the green liquor treated pulp was further subjected to either oxygen delignification or mechanical refining prior to the enzymatic hydrolysis, the conversion rate increased to around 55% and 60%, respectively. Furthermore, combination of oxygen delignification and refining further increased the total sugar conversion to 78% of the total sugar in wood, approximately equal to that of the mixed southern hardwoods. 相似文献
1000.
Hasan Metin Aktulga Chao Yang Esmond G. Ng Pieter Maris James P. Vary 《Concurrency and Computation》2014,26(16):2631-2651
We describe an efficient and scalable symmetric iterative eigensolver developed for distributed memory multi‐core platforms. We achieve over 80% parallel efficiency by major reductions in communication overheads for the sparse matrix‐vector multiplication and basis orthogonalization tasks. We show that the scalability of the solver is significantly improved compared to an earlier version, after we carefully reorganize the computational tasks and map them to processing units in a way that exploits the network topology. We discuss the advantage of using a hybrid OpenMP/MPI programming model to implement such a solver. We also present strategies for hiding communication on a multi‐core platform. We demonstrate the effectiveness of these techniques by reporting the performance improvements achieved when we apply our solver to large‐scale eigenvalue problems arising in nuclear structure calculations. Because sparse matrix‐vector multiplication and inner product computation constitute the main kernels in most iterative methods, our ideas are applicable in general to the solution of problems involving large‐scale symmetric sparse matrices with irregular sparsity patterns. Copyright © 2013 John Wiley & Sons, Ltd. 相似文献