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31.
May Lee Low Cheang Wei Chan Pei Ying Ng Ing Hong Ooi Mohd Jamil Maah Soi Moi Chye 《Journal of Coordination Chemistry》2017,70(2):223-241
Three ternary copper(II) complexes, [Cu(phen)(L-phe)Cl]·2H2O, [Cu(phen)(L-leu)Cl]·4½H2O, and [Cu(phen)(L-tyr)Cl]·3H2O, and four binary copper(II) complexes, [Cu(phen)Cl2], Cu(L-phe)2·½H2O, Cu(L-leu)2·½H2O, and Cu(L-tyr)2·H2O (where phen = 110-phenanthroline, L-phe = L-phenylalanine, L-tyr = L-tyrosine, L-leu = L-leucine and Cl- = chloride), were synthesized and characterized by elemental analysis, spectroscopic techniques (FTIR, UV–visible, fluorescence spectroscopy), magnetic susceptibility, molar conductivity, and lipophilicity measurement. X-ray diffraction determination of a single crystal of [Cu(phen)(L-tyr)Cl] showed two independent molecules in the asymmetric unit, each with the same distorted square pyramidal geometry about copper(II). p-Nitrosodimethylaniline assay revealed that the three ternary complexes were better inducers of reactive oxygen species over time than binary complexes, CuCl2, and free ligands. All the copper(II) complexes in this series inhibited the three proteolytic activities in the order Trypsin-like > Caspase-like > Chymotrypsin-like. In terms of anticancer properties, the copper(II)-phen complexes had GI50 values of less than 4 μM against MCF-7, HepG2, CNE1 and A549 cancer cell lines, more potent than cisplatin. 相似文献
32.
Recently one of us derived the action of modified gravity consistent with the holographic and new-agegraphic dark energy.
In this paper, we investigate the stability of the Lagrangians of the modified gravity as discussed in (Setare in Int J Mod
Phys D 17:2219, 2008; Setare in Astrophys Space Sci 326:27, 2010). We also calculate the statefinder parameters which classify
our dark energy model. 相似文献
33.
Mubasher Jamil K. Karami A. Sheykhi 《International Journal of Theoretical Physics》2011,50(10):3069-3077
Motivated by recent works (Saridakis in Phys. Lett. B 660:138, 2008; Sheykhi in Int. J. Mod. Phys. D 19(3):305, 2010), we investigate the new agegraphic model of dark energy in the framework of RS II braneworld. We also include the case of
variable gravitational constant G in our model. Moreover, we reconstruct the potential and the dynamics of the quintessence, tachyon, K-essence and dilaton
scalar field models according to the evolutionary behavior of the new agegraphic dark energy model in RS II braneworld cosmology
including varying G. 相似文献
34.
A study of the effect of laser beam geometries on laser bending of sheet metal by buckling mechanism
Laser beam forming has emerged as a new and very promising technique to form sheet metal by thermal residual stresses. The objective of this work is to investigate numerically the effect of rectangular beam geometries, with different transverse width to length aspect ratio, on laser bending process of thin metal sheets, which is dominated by buckling mechanism. In this paper, a comprehensive thermal and structural finite element (FE) analysis is conducted to investigate the effect that these laser beam geometries have on the process and on the final product characteristics. To achieve this, temperature distributions, deformations, plastic strains, stresses, and residual stresses produced by different beam geometries are compared. The results suggest that beam geometries play an important role in the resulting temperature distributions on the workpiece. Longer beam dimensions in the scanning direction (in relation to its lateral dimension) produce higher temperatures due to longer beam–material interaction time. This affects the bending direction and the magnitude of the bending angles. Higher temperatures produce more plastic strains and hence higher deformation. This shows that the temperature-dependent yield stress plays a more dominant role in the deformation of the plate than the spread of the beam in the transverse direction. Also, longer beams have a tendency for the scanning line to curve away from its original position to form a concave shape. This is caused by buckling which develops tensile plastic strains along both ends of the scanning path. The buckling effect produces the opposite curve profile; convex along the tranverse direction and concave along the scanning path. 相似文献
35.
Mg-doped ZnO nanoparticles were synthesized by a simple chemical method at low temperature with Mg:Zn atomic ratio from 0
to 7%. The synthesis process is based on the hydrolysis of zinc acetate dihydrate and magnesium acetate tetrahydrate were
heated under refluxing at 65 °C using methanol as a solvent. X-ray diffraction analysis reveals that the Mg-doped ZnO crystallizes
in a wurtzite structure with crystal size of 5–12 nm. These nanocrystals self-aggregated themselves into hollow spheres of
size of 800–1100 nm. High resolution transmission electron microscopy images show that each sphere is made up of numerous
nanoparticles of average diameter 5–11 nm. The XRD patterns, SEM and TEM micrographs of doping of Mg in ZnO confirmed the
formation of hollow spheres indicating that the Mg2+ is successfully substituted into the ZnO host structure of the Zn2+ site. Furthermore, the UV–Vis spectra and photoluminescence (PL) spectra of the ZnO nanoparticles were also investigated.
The band gap of the nanoparticles can be tuned in the range of 3.36–3.55 eV by the use of the dopants. 相似文献
36.
We study the coupling of a tetraquark system to an exchanged meson-meson channel, using a pure gluonic theory based four-quark
potential matrix model which is known to fit well a large number of data points for lattice simulations of different geometries of a four-quark
system. We find that if this minimal-area-based potential matrix replaces the earlier used simple Gaussian form for the gluon
field overlap factor f in its off-diagonal terms, the resulting T -matrix and phase shifts develop an angle dependence whose partial-wave analysis reveals D wave and higher angular-momentum components in it. In addition to the obvious implications of this result for the meson-meson
scattering, this new feature indicates the possibility of orbital excitations influencing properties of meson-meson molecules
through a polarization potential. We have used a formalism of the resonating group method, treated kinetic energy and overlap
matrices on model of the potential matrix, but decoupled the resulting complicated integral equations through the Born approximation.
In this exploratory study we have used a quadratic confinement and not included the spin dependence; we also used the approximation
of equal constituent quark masses. 相似文献
37.
In this paper, we explored the conservation laws of cylindrically symmetric non-static space–times by using direct integration technique. This classification also covers non-static plane symmetric space–times, static cylindrically symmetric space–times and plane symmetric static space–times. In this paper, we will only present the results of non-static cylindrically symmetric and non-static plane symmetric space–times. The results of static cylindrically symmetric space–times and plane static space–times can be found in Shabbir and Khan (Mod Phys Lett A 25:525, 2010). It turns out that the non-static cylindrically symmetric space–times admit four, five, or seven conservation laws. It is important to note that the above space–times admit at least one or at the most four extra conservation laws. 相似文献
38.
The velocity field and the associated shear stress corresponding to the longitudinal oscillatory flow of a generalized second grade fluid, between two infinite coaxial circular cylinders, are determined by means of the Laplace and Hankel transforms. Initially, the fluid and cylinders are at rest and at t = 0+ both cylinders suddenly begin to oscillate along their common axis with simple harmonic motions having angular frequencies Ω1 and Ω2. The solutions that have been obtained are presented under integral and series forms in terms of the generalized G and R functions and satisfy the governing differential equation and all imposed initial and boundary conditions. The respective solutions for the motion between the cylinders, when one of them is at rest, can be obtained from our general solutions. Furthermore, the corresponding solutions for the similar flow of ordinary second grade fluid and Newtonian fluid are also obtained as limiting cases of our general solutions. At the end, the effect of different parameters on the flow of ordinary second grade and generalized second grade fluid are investigated graphically by plotting velocity profiles. 相似文献
39.
40.
The velocity field and the adequate shear stress corresponding to the flow of a generalized Burgers’ fluid model, between two infinite co-axial cylinders, are determined by means of Laplace and finite Hankel transforms. The motion is due to the inner cylinder that applies a time dependent torsional shear to the fluid. The solutions that have been obtained, presented in series form in terms of usual Bessel functions J1( ? ), J2( ? ), Y1( ? ) and Y2( ? ), satisfy all imposed initial and boundary conditions. Moreover, the corresponding solutions for Burgers’, Oldroyd-B, Maxwell, second grade, Newtonian fluids and large-time transient solutions for generalized Burgers’ fluid are also obtained as special cases of the present general solutions. The effect of various parameters on large-time and transient solutions of generalized Burgers’ fluid is also discussed. Furthermore, for small values of the material parameters, λ2 and λ4 or λ1, λ2, λ3 and λ4, the general solutions corresponding to generalized Burgers’ fluids are going to those for Oldroyd-B and Newtonian fluids, respectively. Finally, the influence of the pertinent parameters on the fluid motion, as well as a comparison between models, is shown by graphical illustrations. 相似文献