排序方式: 共有33条查询结果,搜索用时 390 毫秒
1.
Cyriac Vipin Ismayil Noor I. M. Mishra Kuldeep Chavan Chetan Bhajantri Rajashekhar F. Masti Saraswati P. 《Cellulose (London, England)》2022,29(6):3271-3291
Cellulose - In this paper, we report the effect of doping sodium iodide (NaI) salt into a polymer blend matrix of sodium carboxymethyl cellulose (NaCMC) and poly(vinyl alcohol) (PVA). Solution... 相似文献
2.
J. D. Sudha Subrata Pradhan Heera Viswanath Jisha Unnikrishnan Priyanka Brahmbhatt M. S. Manju 《Journal of Thermal Analysis and Calorimetry》2014,115(1):743-750
Thermosetting blend system of co-cured cyanate ester with epoxy resin is receiving importance for high technological applications because of its wide range of thermo-mechanical, rheological, and electrical properties. However, processing of these system warrant proper knowledge of the rheological behavior of the blend during the curing process. This article discusses the rheological behavior of the blend systems with respect to the pot life, gel time, gelation temperature and also evaluated fitting parameters for the prediction of gelation time and viscosity during the entire curing process from the isothermal rheological measurements. 相似文献
3.
J. Barzola-Quiquia R. Höhne M. Rothermel A. Setzer P. Esquinazi V. Heera 《The European Physical Journal B - Condensed Matter and Complex Systems》2008,61(2):127-130
In this work we have investigated the changes of the magnetic
properties of highly oriented pyrolytic graphite samples after
irradiation either with ~3×1014 protons or 3.5×1013 ... 3.5×1014 iron ions with energies in
the MeV range. Our results show that iron and proton irradiations can
produce similar paramagnetic contributions depending on the
implantation temperature. However, only protons induce a
ferromagnetic effect. 相似文献
4.
Tiffany Abitbol Heera S. Marway Stephanie A. Kedzior Xuan Yang Anne Franey Derek G. Gray Emily D. Cranston 《Cellulose (London, England)》2017,24(3):1287-1293
Carboxylated cellulose nanocrystals (CNCs) were decorated with CdSe/ZnS quantum dots (QDs) using a carbodiimide chemistry coupling approach. The one-step covalent modification was supported by nanoscale imaging, which showed QDs clustered on and around the CNCs after coupling. The QD–CNC hybrid nanoparticles remained colloidally stable in aqueous suspension and were fluorescent, exhibiting the broad excitation and narrow emission profile characteristic of the QDs. QD–CNCs in nanocomposite films imparted strong fluorescence within CNC-compatible matrices at relatively low loadings (0.15 nmol QDs/g of dry film), without altering the overall physical properties or self-assembly of the CNCs. The hybrid QD–CNCs may find applications in nanoparticle tracking, bio-imaging, optical/sensing devices, and anti-counterfeit technologies. 相似文献
5.
Nitrogen doped TiO2 (TiO2−xNx) with a homogenous anatase phase was synthesized, using β-alanine as a nitrogen precursor and ethanol as a oxygen depriving
agent in the concentration range of 0.05, 0.10, 0.15 and 0.2 at% and were characterized by Powder X-ray Diffraction (PXRD),
X-ray Photoelectron Spectra (XPS), Scanning Electron Microscope (SEM), Fourier Transform Infrared (FT-IR) and UV–visible Diffused
Reflectance Spectroscopic (DRS) techniques. Ethanol deprives the surface oxygen, thereby generating oxygen defects whose concentration
was evaluated by FTIR, Photoluminescence (PL) and Electron Spin Resonance (ESR) studies. FTIR analysis reveal that concentration
of oxygen vacancies/defects (Vo) decreases as the nitrogen concentration increases leading to the reduction in the Ti–O bond length. This results in a shift
of the IR absorption peak towards a low wave number as predicted by simple physical harmonic oscillator model. The Ti 2p3/2 XPS spectra of TiO2−xNx shifts to lower binding energies due to the increase in the electron densities around the Ti atoms indicating the formation
of Ti3+ in the doped samples. N2 adsorption–desorption isotherms measurements show a slight increase in the Brunner–Emmet–Teller (BET) surface area, pore
diameter, mesopore volume, while the crystallite size and the morphology were also effected by the nitrogen doping. The equilibrium
adsorption of Toluene molecules on the photocatalyst surface follows Langmuir theory and the rate controlling step could be
the surface reaction of the adsorbed Toluene molecules. 相似文献
6.
The kinetics of copper ion (Cu(II)) removal from aqueous solution by pyrolytic tire char was modeled using five different conventional models. A modification to these models was also developed through a modified equation that accounts for precipitation. Conventional first- and second-order reaction models did not fit the copper sorption kinetics well, indicating a lack of simple rate-order dependency on solute concentration. Instead, a reversible first-order rate reaction showed the best fit to the data, indicating a dependence on surface functional groups. Due to the varying solution pH during the sorption process, modified external and internal mass transfer models were employed. Results showed that the sorption of copper onto oxygenated chars was limited by external mass transfer and internal resistance with and without the modification. However, the modification of the sorption process produced very different results for unoxygenated chars, which showed neither internal nor external limitation to sorption. Instead, its slow sorption rate indicates a lack of surface functional groups. The sorption of Cu(II) by oxygenated and unoxygenated chars was also found to occur via three and two distinct stages, respectively. 相似文献
7.
Ilyas Suhaib Umer Pendyala Rajashekhar Narahari Marneni 《Journal of Thermal Analysis and Calorimetry》2019,135(2):1197-1209
Journal of Thermal Analysis and Calorimetry - The carbon nanotubes are considered as one of the highest thermal conductive material which is having a variety of heat transfer applications. The... 相似文献
8.
Krishna H Krishnamurthy SS Nethaji M Murugavel R Prabusankar G 《Dalton transactions (Cambridge, England : 2003)》2007,(27):2908-2914
The reactivity of (eta(3)-allyl)palladium chloro dimers [(1-R-eta(3)-C(3)H(4))PdCl](2) (R = H or Me) towards a sterically hindered diphosphazane ligand [EtN{P(OR)(2)}(2)] (R = C(6)H(3)(Pr(i))(2)-2,6), has been investigated under different reaction conditions. When the reaction is carried out using NH(4)PF(6) as the halide scavenger, the cationic complex [(1-R-eta(3)-C(3)H(4))Pd{EtN(P(OR)(2))(2)}]PF(6) (R = H or Me) is formed as the sole product. In the absence of NH(4)PF(6), the initially formed cationic complex, [(eta(3)-C(3)H(5))Pd{EtN(P(OR)(2))(2)}]Cl, is transformed into a mixture of chloro bridged complexes over a period of 4 days. The dinuclear complexes, [(eta(3)-C(3)H(5))Pd(2)(mu-Cl)(2){P(O)(OR)(2)}{P(OR)(2)(NHEt)}] and [Pd(mu-Cl){P(O)(OR)(2)}{P(OR)(2)(NHEt)}](2) are formed by P-N bond hydrolysis, whereas the octa-palladium complex [(eta(3)-C(3)H(5))(2-Cl-eta(3)-C(3)H(4))Pd(4)(mu-Cl)(4)(mu-EtN{P(OR)(2)}(2))](2), is formed as a result of nucleophilic substitution by a chloride ligand at the central carbon of an allyl fragment. The reaction of [EtN{P(OR)(2)}(2)] with [(eta(3)-C(3)H(5))PdCl](2) in the presence of K(2)CO(3) yields a stable dinuclear (eta(3)-allyl)palladium(I) diphosphazane complex, [(eta(3)-C(3)H(5))[mu-EtN{P(OR)(2)}(2)Pd(2)Cl] which contains a coordinatively unsaturated T-shaped palladium center. This complex exhibits high catalytic activity and high TON's in the catalytic hydrophenylation of norbornene. 相似文献
9.
The effect of rotation and anisotropy on the onset of double diffusive convection in a horizontal porous layer is investigated
using a linear theory and a weak nonlinear theory. The linear theory is based on the usual normal mode technique and the nonlinear
theory on the truncated Fourier series analysis. Darcy model extended to include time derivative and Coriolis terms with anisotropic
permeability is used to describe the flow through porous media. The effect of rotation, mechanical and thermal anisotropy
parameters, and the Prandtl number on the stationary and overstable convection is discussed. It is found that the effect of
mechanical anisotropy is to allow the onset of oscillatory convection instead of stationary. It is also found that the existence
of overstable motions in case of rotating porous medium is not restricted to a particular range of Prandtl number as compared
to the pure viscous fluid case. The finite amplitude analysis is performed to find the thermal and solute Nusselt numbers.
The effect of various parameters on heat and mass transfer is also investigated. 相似文献
10.
M. S. Malashetty Ioan Pop Rajashekhar Heera 《Continuum Mechanics and Thermodynamics》2009,21(4):317-339
Double diffusive convection in a fluid-saturated rotating porous layer is studied when the fluid and solid phases are not
in local thermal equilibrium, using both linear and nonlinear stability analyses. The Brinkman model that includes the Coriolis
term is employed as the momentum equation. A two-field model that represents the fluid and solid phase temperature fields
separately is used for the energy equation. The onset criterion for stationary, oscillatory, and finite amplitude convection
is derived analytically. It is found that small inter-phase heat transfer coefficient has significant effect on the stability
of the system. There is a competition between the processes of thermal diffusion, solute diffusion, and rotation that causes
the convection to set in through either oscillatory or finite amplitude mode rather than stationary. The effect of solute
Rayleigh number, porosity modified conductivity ratio, Lewis number, diffusivity ratio, Vadasz number, and Taylor number on
the stability of the system is investigated. The nonlinear theory based on the truncated representation of Fourier series
method predicts the occurrence of subcritical instability in the form of finite amplitude motions. The effect of thermal non-equilibrium
on heat and mass transfer is also brought out. Some of the convection systems previously reported in the literature is shown
to be special cases of the system presented in this study. 相似文献