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61.
Chiral SU2 × SU2 breaking, Cabibbo angle, non-electromagnetic isospin breaking, η → 3π decay rate, and pion and kaon mass differences are related to one another in a nonlinear Lagrangian model of broken chiral SU3 × SU3 symmetry. The agreement with experiment is very good. 相似文献
62.
Transmittance measurements were carried out for LiF thin films directly after preparation, then one day, one week, four weeks
and six weeks later. The aging effect on the optical properties of the film was thus studied. This showed that the aged LiF
films have refractive indices larger than those of fresh films. 相似文献
63.
Jamal Aalaie Ebrahim Vasheghani-Farahani Mohammad Ali Semsarzadeh Ali Rahmatpour 《Journal of Macromolecular Science: Physics》2013,52(5):1017-1027
Novel semi-Interpenetrating Polymer Network (semi-IPN) hydrogels based on partially Hydrolyzed Polyacrylamide (HPAM) and Poly(Vinyl Alcohol) (PVA) were prepared by solution crosslinking using chromium triacetate. Effects of PVA content on the gelation process and swelling behavior in tap water and different electrolyte solutions were investigated. Study of the gelation behavior using dynamic rheometery showed that the limiting storage modulus of the semi-IPN gels decreased with increasing PVA content. It was also found that increasing the PVA content increases the loss factor, indicating that the viscous properties of this gelling system increase more strongly than the elastic properties. The swelling ratio of the semi-IPN gels in tap water decreased as the concentration of the PVA increased. However, the semi-IPN gels showed lower salt sensitivity factor in synthetic oil reservoir water as compared with HPAM gels. Therefore, they are potentially good candidates for enhanced oil recovery applications. 相似文献
64.
65.
Ebrahim Hashemi 《Mediterranean Journal of Mathematics》2013,10(1):111-121
For a monoid M, we introduce nil-Armendariz rings relative to M, which are a generalization of nil-Armendariz and M-Armendariz rings, and investigate their properties. First we show that semicommutative rings are nil-Armendariz relative to every unique product monoid M. Also it is shown that for a strictly totally ordered monoid M and an ideal I of R, if I is a semicommutative subrng of R and R/I nil-Armendariz relative to M, then R is nil-Armendariz relative to M. Then we show that if R is a semicommutative ring and nil-Armendariz relative to M, then R is nil-Armendariz relative to M × N, where N is a unique product monoid. As corollaries we obtain some results of [2] and [10]. 相似文献
66.
S. Tavakol M. R. Nikpour A. Amani M. Soltani S. M. Rabiee S. M. Rezayat P. Chen M. Jahanshahi 《Journal of nanoparticle research》2013,15(1):1-16
Surface morphology, surface wettability, and size distribution of biomaterials affect their in vitro and in vivo bone regeneration potential. Since nano-hydroxyapatite has a great chemical and structural similarity to natural bone and dental tissues, incorporated biomaterial of such products could improve bioactivity and bone bonding ability. In this research, nano-hydroxyapatite (23 ± 0.09 nm) and its composites with variety of chitosan content [2, 4, and 6 g (45 ± 0.19, 32 ± 0.12, and 28 ± 0.12 nm, respectively)] were prepared via an in situ hybridization route. Size distribution of the particles, protein adsorption, and calcium deposition of powders by the osteoblast cells, gene expression and percentage of new bone formation area were investigated. The highest degree of bone regeneration potential was observed in nano-hydroxyapatite powder, while the bone regeneration was lowest in nano-hydroxyapatite with 6 g of chitosan. Regarding these data, suitable size distribution next to size distribution of hydroxyapatite in bone, smaller size, higher wettability, lower surface roughness of the nano-hydroxyapatite particles and homogeneity in surface resulted in higher protein adsorption, cell differentiation and percentage of bone formation area. Results obtained from in vivo and in vitro tests confirmed the role of surface morphology, surface wettability, mean size and size distribution of biomaterial besides surface chemistry as a temporary bone substitute. 相似文献
67.
Ebrahim Kianmehr Narges Shamsaei Zafarghandi Mohammad Ghanbari 《Molecular diversity》2013,17(2):383-388
Novel $N$ -alkyl-2-(alkylthio)-1 $H$ -imidazole derivatives were synthesized in a single step by an efficient and simple method in high yields. Readily available starting materials, mild reaction conditions, operational simplicity and novelty are the key advantages of this method. Besides their novel structures, these compounds may have important biological activities and industrial applications. 相似文献
68.
69.
The improvement of numerical modeling in the solution of incompressible viscous flow problems using finite element method based on spherical Hankel shape functions
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In this paper, the finite element method with new spherical Hankel shape functions is developed for simulating 2‐dimensional incompressible viscous fluid problems. In order to approximate the hydrodynamic variables, the finite element method based on new shape functions is reformulated. The governing equations are the Navier‐Stokes equations solved by the finite element method with the classic Lagrange and spherical Hankel shape functions. The new shape functions are derived using the first and second kinds of Bessel functions. In addition, these functions have properties such as piecewise continuity. For the enrichment of Hankel radial basis functions, polynomial terms are added to the functional expansion that only employs spherical Hankel radial basis functions in the approximation. In addition, the participation of spherical Bessel function fields has enhanced the robustness and efficiency of the interpolation. To demonstrate the efficiency and accuracy of these shape functions, 4 benchmark tests in fluid mechanics are considered. Then, the present model results are compared with the classic finite element results and available analytical and numerical solutions. The results show that the proposed method, even with less number of elements, is more accurate than the classic finite element method. 相似文献
70.
The behavior of composite coated Al electrodes fabricated by surface mechanical alloying ‘SMA’ was studied. The work was accomplished using Cyclic voltammetry and electrochemical impedance spectroscopy (EIS) techniques in alkaline media were done at room temperature. Results show hydroxyl ions accumulate on the surface due to Al deformation micro cavities filling with until full charge blockage reached. A barrier cover layer development causing an increase of both resistance and capacitance as it becomes more stable and thinner with exposure time increase. Migrating hydroxyl ion inside micro cavity changed its composition from Al2O3 to stable tetrahedral aluminate ions. Therefore future benefits could be reached by developing such surfaces having charge accumulation that enables environmental interaction. 相似文献