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961.
A series of Zn(II)-Schiff bases I, II and III complexes were synthesized by reaction of o-phenylenediamine with 3-methylsalicylaldehyde, 4-methylsalicylaldehyde and 5-methylsalicylaldehyde. These complexes were characterized using FT-IR, UV-Vis, Diffuse reflectance UV-Vis, elemental analysis and conductivity. Complex III was characterized by XRD single crystal, which crystallizes in the triclinic system, space group P-1, with lattice parameters a?=?9.5444(2) Å, b?=?11.9407(2) Å, c?=?21.1732(3) Å, V?=?2390.24(7) Å3, D c ?=?1.408 Mg m?3, Z?=?4, F(000)?=?1050, GOF?=?0.981, R1?=?0.0502, wR2?=?0.1205. Luminescence property of these complexes was investigated in DMF solution and in the solid state. Computational study of the electronic properties of complex III showed good agreement with the experimental data. 相似文献
962.
Loredo A Plessy A El Hafidi A Hamzaoui N 《The Journal of the Acoustical Society of America》2011,129(4):1905-1918
A numerical vibroacoustic model that can manage multilayered plates locally covered with damping patches is presented. All the layers can have an on-axis orthotropic viscoelastic behavior. Continuity of displacements and transverse shear stresses at each interface is enforced, which permits to write the entire displacement field in function of the displacements of the--common--first layer, leading to a two-dimensional plate model. The problem is then discretized by Rayleigh-Ritz's method using a trigonometric basis that includes both sine and cosine functions in order to treat various boundary conditions. The excitation can be of mechanical kind (concentrated or distributed forces) or of acoustic kind (plane wave of any incidence, diffuse field, etc.). The model permits to compute different vibroacoustic indicators: the mean square velocity of the plate, the radiation efficiency, and the transmission loss. Comparisons between the present model and numerical results from literature or finite element computations show that the model gives good results in both mechanical and acoustical aspects. Then, a comparison of the effects of different distributions of patches is presented. The role of the surface covering rate is first discussed, followed by a study involving different geometries for the same surface covering rate. 相似文献
963.
Seyed Ali Salehizadeh Dariush Souri 《Journal of Physics and Chemistry of Solids》2011,72(11):1381-1385
The glass transition temperature dependence to heating rate and therefore the activation energy (ΔH?) of the glass transition of (60-x)V2O5–xNiO–40TeO2 oxide glasses with 0≤x≤20 (in mol%) were investigated at heating rates φ (=3 6, 9, 10 and 12 K/min) using differential scanning calorimetry (DSC). The heating rate dependence of Tg was used to investigate the applicability of different theoretical models describing the glass transition. Using the application of Moynihan and Kissinger et al. models to the present data, different values of (ΔH?) at each different heating-rate regions were obtained. The fragility parameter (m=ΔH?/R Tg) was ∼24.98 for x=10 mol%, suggesting that this glass may be considered as a rather strong glass (fragility index m∼>20 is an indication of fragile glass). Also the compositional dependence of Tg and ΔH? was investigated. 相似文献
964.
The generation of aerodynamic sound by the interaction of flow at a Reynolds number of 150 and a Mach number of 0.2 with a rigid square cylinder attached to a rigid thin flat plate is numerically investigated. When the length of the plate is varied from L=0.5D to 6D, where D is the side length of the square cylinder, the results can be grouped into three distinct regimes. For the first regime (L?D), the sound levels decrease with increasing plate length. A 3 dB sound reduction is obtained when the length of the plate is D. For the second regime (1.25D?L?4.75D), the sound levels increase with increasing plate length. For the third regime (5D?L?6D), the sound levels decrease as the length of the plate increases but the levels are higher than for the other regimes. Results also show that the lift fluctuation is the dominant sound source. These acoustic results can be explained in terms of the fluid mechanics occurring in the near wake of the cylinder. 相似文献
965.
Yang TY Balakrishnan J Volmer F Avsar A Jaiswal M Samm J Ali SR Pachoud A Zeng M Popinciuc M Güntherodt G Beschoten B Özyilmaz B 《Physical review letters》2011,107(4):047206
We report on the first systematic study of spin transport in bilayer graphene (BLG) as a function of mobility, minimum conductivity, charge density, and temperature. The spin-relaxation time τ(s) scales inversely with the mobility μ of BLG samples both at room temperature (RT) and at low temperature (LT). This indicates the importance of D'yakonov-Perel' spin scattering in BLG. Spin-relaxation times of up to 2 ns at RT are observed in samples with the lowest mobility. These times are an order of magnitude longer than any values previously reported for single-layer graphene (SLG). We discuss the role of intrinsic and extrinsic factors that could lead to the dominance of D'yakonov-Perel' spin scattering in BLG. In comparison to SLG, significant changes in the carrier density dependence of τ(s) are observed as a function of temperature. 相似文献
966.
967.
Nanoplates of the three-dimensional coordination polymer, {[Cd(3)(3-pyc)(4)(N(3))(2)(H(2)O)](n) (1), 3-pyc(-)=pyridine-3-carboxylate), have been synthesized by a sonochemical process and characterized by scanning electron microscopy, X-ray powder diffraction, IR spectroscopy and elemental analyses. Cadmium(II) oxide nanoparticles were prepared from thermal decomposition in oleic acid and direct calcination of compound 1 at different temperatures. The thermal stability of nano-sized compound 1 was studied by thermal gravimetric (TG) and differential thermal analyses (DTA). Results show that the size and morphology of the CdO nanoparticles are dependent upon the particles size of compound 1 and the thermolysis temperature. A decrease in the particle size of compound 1 leads to a decrease in the particle size of the CdO, while an increase in the processing temperature leads to an increase in the particle size of the produced cadmium(II) oxide nano-particles. 相似文献
968.
Malek Taher Maghsoodlou Ghasem Marandi Nourallah Hazeri Sayyed Mostafa Habibi-Khorassani Ali Akbar Mirzaei 《Molecular diversity》2011,15(1):227-231
5-Aryl-6-(alkyl- or aryl-amino)-1,3-dimethylfuro [2,3-d]pyrimidine derivatives were obtained by in situ reaction alkyl or aryl isocyanides and pyridinecarbaldehyde derivatives in
the presence of 1,3-dimethylbarbituric acid in dichloromethane without any prior activation or modifications. 相似文献
969.
The aim of this review is to provide an overview of the contributions and recent advances made by Iranian scientists in the
field of isocyanide-based reactions between 1999 and 2009. With over 100 publications during this period, Iranians are responsible
for approximately 10% of all publications in the world involving isocyanide-based multicomponent reactions (IMCRs). Some important
aspects of these IMCRs include the execution of reactions in green reaction mediums like water or ethanol, high atom economies,
mild reaction conditions, high yields, and catalyst-free processes. On the other hand, in most of these reactions, new classes
of heterocyclic compounds with potential biological and medicinal activities have been reported. 相似文献
970.
Ali M. Soltani Seyed H. Tabatabaeian Payam Hanafizadeh Jahanyar Bamdad Soofi 《Journal of nanoparticle research》2011,13(12):7303-7312
Dozens of countries are executing national nanotechnology plans. No rigorous evaluation scheme for these plans exists, although
stakeholders—especially policy makers, top-level agencies and councils, as well as the society at large—are eager to learn
the outcome of these policies. In this article, we recommend an evaluation scheme for national nanotechnology policies that
would be used to review the whole or any component part of a national nanotechnology plan. In this scheme, a component at
any level of aggregation is evaluated. The component may be part of the plan’s overarching policy goal, which for most countries
is to create wealth and improve the quality of life of their nation with nanotechnology. Alternatively, the component may
be a programme or an activity related to a programme. The evaluation could be executed at different times in the policy’s
life cycle, i.e., before the policy is formulated, during its execution or after its completion. The three criteria for policy
evaluation are appropriateness, efficiency and effectiveness. The evaluator should select the appropriate qualitative or quantitative
methods to evaluate the various components of national nanotechnology plans. 相似文献