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141.
Pure and Cobalt doped zinc oxide were deposited on glass substrate by Ultrasonic spray method. Zinc acetate dehydrate, Cobalt chloride, 4-methoxyethanol and monoethanolamine were used as a starting materials, dopant source, solvent and stabilizer, respectively. The ZnO samples and ZnO:Co with Cobalt concentration of 2 wt.% were deposited at 300, 350 and 400 °C. The effects of substrate temperature and presence of Co as doping element on the structural, electrical and optical properties were examined. Both pure and Co doped ZnO samples are (0 0 2) preferentially oriented. The X-ray diffraction results indicate that the samples have polycrystalline nature and hexagonal wurtzite structure with the maximum average crystallite size of ZnO and ZnO:Co were 33.28 and 55.46 nm. An increase in the substrate temperature and presence doping the crystallinity of the thin films increased. The optical transmittance spectra showed transmittance higher than 80% within the visible wavelength region. The band gap energy of the thin films increased after doping from 3.25 to 3.36 eV at 350 °C. 相似文献
142.
We investigate the decay property of a Timoshenko system of thermoelasticity in the whole space for both Fourier and Cattaneo laws of heat conduction. We point out that although the paradox of infinite propagation speed inherent in the Fourier law is removed by changing to the Cattaneo law, the latter always leads to a solution with the decay property of the regularity‐loss type. The main tool used to prove our results is the energy method in the Fourier space together with some integral estimates. We derive L2 decay estimates of solutions and observe that for the Fourier law the decay structure of solutions is of the regularity‐loss type if the wave speeds of the first and the second equations in the system are different. For the Cattaneo law, decay property of the regularity‐loss type occurs no matter what the wave speeds are. In addition, by restricting the initial data to with a suitably large s and γ ∈ [0,1], we can derive faster decay estimates with the decay rate improvement by a factor of t?γ/2. Copyright © 2011 John Wiley & Sons, Ltd. 相似文献
143.
Mahdi Shahrokhi Fatemeh Rostami Md Azlin Md Said Saeed Reza Sabbagh Yazdi Syafalni 《Applied Mathematical Modelling》2012
In this study, the effect of different numbers of baffles is investigated using computational simulation. Laboratory measurements using different numbers of constant height baffles in a rectangular primary sedimentation tank are conducted. The velocity fields measured by an Acoustic Doppler Velocimeter (ADV) are used to verify the results of the computational model. The effects of the number of baffles arrangement on the hydraulic performance of primary settling tanks are studied by using two different ways: the parameters of flow pattern and the Flow Through Curves (FTCs) method. The results of both the experimental and computational investigations indicate that increasing the number of baffles in suitable positions provides minimum volume of the recirculation region, dissipates the kinetic energy, creates a uniform flow field in the tank and finally the hydraulic efficiency of the sedimentation tank will be improved. 相似文献
144.
Taib N Aimé A Houmadi S Castano S Barthélémy P Laguerre M Bestel I 《Langmuir : the ACS journal of surfaces and colloids》2012,28(19):7452-7460
Nucleolipids are currently under investigation as vectors for oligonucleotides (ON) delivery thanks to their supramolecular organization properties and their ability to develop specific interactions (i.e., stacking and potential Watson and Crick hydrogen bonds) for lipoplexes formation. To investigate the factors that govern the interaction events at a molecular level and optimize nucleolipid chemical structures, physicochemical experiments (tensiometry, AFM, BAM, and ellipsometry) combined with molecular dynamics simulation were performed on a series of zwitterionic nucleolipids (PUPC, DPUPC, PAPC) featuring a phosphocholine chain (PC). After construction and initial equilibration, simulations of pure nucleolipid bilayers were run for 100 ns at constant temperature and pressure, and their properties were compared to experimental data and to natural dipalmitoylphosphatidylcholine (DPPC) bilayers. Nucleolipid-based membranes are significantly more ordered and compact than DPPC bilayers mainly due to the presence of many intermolecular interactions between nucleoside polar heads. The hydrophilic phosphocholine moieties connected to the 5' hydroxyls are located above the bilayers, penalizing nucleic bases accessibility for further interactions with ON. Hence, a neutral nucleolipid (PUOH) without hydrophilic phosphocholine was inserted in the membranes. Simulations and experimental analysis of nucleolipid membranes in interaction with a single strand RNA structure indicate that PUOH interacts with ON in the subphase. This study demonstrates that molecular modeling can be used to determine the interactions between oligonucleotide and nucleolipids. 相似文献
145.
Ertekin E Winkler MT Recht D Said AJ Aziz MJ Buonassisi T Grossman JC 《Physical review letters》2012,108(2):026401
Hyperdoping has emerged as a promising method for designing semiconductors with unique optical and electronic properties, although such properties currently lack a clear microscopic explanation. Combining computational and experimental evidence, we probe the origin of sub-band-gap optical absorption and metallicity in Se-hyperdoped Si. We show that sub-band-gap absorption arises from direct defect-to-conduction-band transitions rather than free carrier absorption. Density functional theory predicts the Se-induced insulator-to-metal transition arises from merging of defect and conduction bands, at a concentration in excellent agreement with experiment. Quantum Monte Carlo calculations confirm the critical concentration, demonstrate that correlation is important to describing the transition accurately, and suggest that it is a classic impurity-driven Mott transition. 相似文献
146.
MC Galan AT Tran K Bromfield S Rabbani B Ernst 《Organic & biomolecular chemistry》2012,10(35):7091-7097
A new N-benzenesulfonyl-based ionic-liquid mass spectroscopy label (I-Tag2) for covalent attachment to substrates has been prepared. I-Tag2 was used to monitor oligosaccharide elongation and serve as a purification handle. Starting from chemically synthesized I-Tag2-labelled N-acetyl glucosamine (GlcNAc) 1, I-Tag2-LacNAc (Galβ(1-4)GlcNAc) 2 and I-Tag2-Lewis(X) (Galβ(1-4)[Fucα(1-3)]GlcNAc) 3, which are oligosaccharides of biological relevance, were enzymatically prepared. The apparent kinetic parameters for the enzyme catalysed transformations with β-1,4-galactosyltransferase (β-1,4-GalT) and fucosyltransferase VI (FucT VI) were measured by LC-MS demonstrating the applicability and versatility of the new I-Tags in enzymatic transformations with glycosyltransferases. 相似文献
147.
A general method for the synthesis of polyhydroxylated stilbene monofluorinated on the central double bond based on the Suzuki reaction between a bromofluoroolefin and a phenylboronic acid is described. Synthesis of fluorinated analogues of resveratrol and pterostilbene was achieved using this strategy. 相似文献
148.
High‐energy‐resolution diced spherical quartz analyzers for resonant inelastic X‐ray scattering 下载免费PDF全文
Ayman H. Said Thomas Gog Michael Wieczorek XianRong Huang Diego Casa Elina Kasman Ralu Divan Jung Ho Kim 《Journal of synchrotron radiation》2018,25(2):373-377
A novel diced spherical quartz analyzer for use in resonant inelastic X‐ray scattering (RIXS) is introduced, achieving an unprecedented energy resolution of 10.53 meV at the Ir L3 absorption edge (11.215 keV). In this work the fabrication process and the characterization of the analyzer are presented, and an example of a RIXS spectrum of magnetic excitations in a Sr3Ir2O7 sample is shown. 相似文献
149.
Said R. Grace John R. Graef Ercan Tunc 《Journal of Applied Analysis & Computation》2019,9(4):1305-1318
The authors present conditions under which every positive solution $x(t)$ of the integro--differential equation $x^{\prime \prime }(t)=a(t)+\int_{c}^{t}(t-s)^{\alpha-1}[e(s)+k(t,s)f(s,x(s))]ds, \quad c>1, \ \alpha >0,$ satisfies $x(t)=O(tA(t))\textrm{ as }t\rightarrow \infty,$ i.e, $\limsup_{t\rightarrow \infty }\frac{x(t)}{tA(t)}<\infty, \textrm{where} \ A(t)=\int_{c}^{t}a(s)ds.$ From the results obtained, they derive a technique that can be applied to some related integro--differential equations that are equivalent to certain fractional differential equations of Caputo type of any order. 相似文献
150.
In this paper, we will consider the higher‐order functional dynamic equations of the form on an above‐unbounded time scale , where and , . The function is a rd‐continuous function such that . The results extend and improve some known results in the literature on higher order nonlinear dynamic equations. 相似文献