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101.
Yoshinori Namihira Md. Anwar Hossain Taito Koga Md. Ashraful Islam S. M. Abdur Razzak Shubi F. Kaijage Yuki Hirako Hiroki Higa 《Optical Review》2012,19(2):78-81
In this paper, we propose a highly nonlinear dispersion flattened hexagonal photonic crystal fiber (HNDF-HPCF) with nonlinear
coefficients as large as 57.5W−1 km−1 at 1.31 μm wavelength for dental optical coherence tomography (OCT) applications. This HNDF-HPCF offers not only large nonlinear
coefficient but also very flat dispersion slope and very low confinement losses. Using these characteristics of our proposed
PCF, it is shown through simulations by using finite difference method with an anisotropic perfectly matched boundary layer
that this PCF offers the efficient supercontinuum (SC) generation for dental OCT applications at 1.31 μm wavelength using
a picosecond pulse easily produced by commercially available less expensive laser sources. Coherent length of light source
using SC is found 10 μm and the spatial resolutions in the depth direction for dental applications of OCT are found about
6.1 μm for enamel and 6.5 μm for dentin. 相似文献
102.
Nida Iqbal Rabia NazirAnila Asif Aqif Anwar ChaudhryMuhammad Akram Goh Yi FanAftab Akram Rashid AminSung Ha Park Rafaqat Hussain 《Current Applied Physics》2012,12(3):755-759
Polyvinyl alcohol (PVA) coated hydroxyapatite was deposited onto a 316L stainless steel substrate by electrophoretic deposition. Deposition was carried out in a methanol suspension at pH 5.5 using a graphite rod as an anode. Parameters such as PVA concentration, deposition voltage and time were optimized to achieve a homogeneous, crack-free adhesive coating. Techniques such as X-ray diffraction and Fourier transform infrared spectroscopy were used to study the phase composition of the coated materials and the stability of hydroxyapatite in the presence of PVA. 相似文献
103.
Sajid ZI Anwar F Shabir G Rasul G Alkharfy KM Gilani AH 《Molecules (Basel, Switzerland)》2012,17(4):3917-3932
This study appraises the antioxidant and antimicrobial attributes of various solvent extracts (absolute methanol, aqueous methanol, absolute ethanol, aqueous ethanol, absolute acetone, aqueous acetone, and deionized water) from bark, leaves and seeds of Pongamia pinnata (L.) Pierre. Maximum extraction yield of antioxidant components from bark (16.31%), leaves (11.42%) and seeds (21.51%) of P. pinnata was obtained using aqueous methanol (20:80). Of the extracts tested, the bark extract, obtained with aqueous methanol, exhibited greater levels of total phenolics [6.94 g GAE/100 g dry weight (DW)], total flavonoids (3.44 g CE/100 g DW), inhibition of linoleic acid peroxidation (69.23%) and DPPH radical scavenging activity (IC(50) value, 3.21 μg/mL), followed by leaves and seeds extracts. Bark extract tested against a set of bacterial and fungal strains also revealed the strongest antimicrobial activity with the largest inhibition zone and lowest minimum inhibitory concentration (MIC). HPLC analysis of aqueous methanol extracts from bark, leaves and seeds indicated the presence of protocatechuic, ellagic, ferulic, gallic, gentisic, 4-hydroxybenzoic and 4-hydroxycinnamic acids in bark (1.50-6.70 mg/100 g DW); sorbic, ferulic, gallic, salicylic and p-coumaric acids in leaves (1.18-4.71 mg/100 g DW); vanillic, gallic and tannic acids in seeds (0.52-0.65 mg/100 g DW) as the main phenolic acids. The present investigation concludes that the tested parts of P. pinnata, in particular the bark, have strong potential for the isolation of antioxidant and antimicrobial agents for functional food and pharmaceutical uses. 相似文献
104.
105.
Mazaahir Kidwai Anwar Jahan Ritika Chauhan Neeraj Kumar Mishra 《Tetrahedron letters》2012,53(14):1728-1731
A new green protocol has been developed for the synthesis of 2H-indazolo[2,1-b]phthalazine-triones via one-pot, three-component condensation reaction of aromatic aldehydes with 1,3-dicarbonyl compounds and phthalhydrazide using reusable dodecylphosphonic acid (DPA) as heterogeneous solid acid catalyst under solvent-free conditions. This protocol provides a novel and improved method for obtaining 2H-indazolo[2,1-b]phthalazine-triones in terms of good yields with little catalyst loading. 相似文献
106.
A set W of the vertices of a connected graph G is called a resolving set for G if for every two distinct vertices u, v ∈ V (G) there is a vertex w ∈ W such that d(u, w) ≠ d(v, w). A resolving set of minimum cardinality is called a metric basis for G and the number of vertices in a metric basis is called the metric dimension of G, denoted by dim(G). For a vertex u of G and a subset S of V (G), the distance between u and S is the number min s∈S d(u, s). A k-partition Π = {S 1 , S 2 , . . . , S k } of V (G) is called a resolving partition if for every two distinct vertices u, v ∈ V (G) there is a set S i in Π such that d(u, Si )≠ d(v, Si ). The minimum k for which there is a resolving k-partition of V (G) is called the partition dimension of G, denoted by pd(G). The circulant graph is a graph with vertex set Zn , an additive group of integers modulo n, and two vertices labeled i and j adjacent if and only if i-j (mod n) ∈ C , where CZn has the property that C =-C and 0 ■ C. The circulant graph is denoted by Xn, Δ where Δ = |C|. In this paper, we study the metric dimension of a family of circulant graphs Xn, 3 with connection set C = {1, n/2 , n-1} and prove that dim(Xn, 3 ) is independent of choice of n by showing that dim(Xn, 3 ) ={3 for all n ≡ 0 (mod 4), 4 for all n ≡ 2 (mod 4). We also study the partition dimension of a family of circulant graphs Xn,4 with connection set C = {±1, ±2} and prove that pd(Xn, 4 ) is independent of choice of n and show that pd(X5,4 ) = 5 and pd(Xn,4 ) ={3 for all odd n ≥ 9, 4 for all even n ≥ 6 and n = 7. 相似文献
107.
S.Nadeem Anwar Hussain M.Y.Malik T.Hayat 《应用数学和力学(英文版)》2009,30(10):1255-1262
This study derives the analytic solutions of boundary layer flows bounded by a shrinking sheet. With the similarity transformations, the partial differential equations are reduced into the ordinary differential equations which are then solved by the homotopy analysis method (HAM). Two-dimensional and axisymmetric shrinking flow cases are discussed. 相似文献
108.
Numerical investigations of asymmetric flow of a micropolar fluid between two porous disks 总被引:1,自引:0,他引:1
Numerical solution is presented for the two- dimensional flow of a micropolar fluid between two porous coaxial disks of different permeability for a range of Reynolds number Re (-300≤ Re 〈 0) and permeability parameter A (1.0≤A ≤2.0). The main flow is superimposed by the injection at the surfaces of the two disks. Von Karman's similarity transformations are used to reduce the governing equations of motion to a set of non-linear coupled ordinary differential equations (ODEs) in dimensionless form. An algorithm based on the finite difference method is employed to solve these ODEs and Richardson's extrapolation is used to obtain higher order accuracy. The results indicate that the parameters Re and A have a strong influence on the velocity and microrotation profiles, shear stresses at the disks and the position of the viscous/shear layer. The micropolar material constants cl, c2, c3 have profound effect on microrotation as compared to their effect on streamwise and axial velocity profiles. The results of micropolar fluids are compared with the results for Newtonian fluids. 相似文献
109.
An exact solution is presented for the hydromagnetic natural convection boundary layer flow past an infinite vertical flat
plate under the influence of a transverse magnetic field with magnetic induction effects included. The transformed ordinary
differential equations are solved exactly, under physically appropriate boundary conditions. Closed-form expressions are obtained
for the non-dimensional velocity (u), non-dimensional induced magnetic field component (B
x
) and wall frictional shearing stress i.e. skin friction function (τ
x
) as functions of dimensionless transverse coordinate (η), Grashof free convection number (G
r
) and the Hartmann number (M). The bulk temperature in the boundary layer (Θ) is also evaluated and shown to be purely a function of M. The Rayleigh flow distribution (R) is derived and found to be a function of both Hartmann number (M) and the buoyant diffusivity parameter (ϑ
*). The influence of Grashof number on velocity, induced magnetic field and wall shear stress profiles is computed. The response
of Rayleigh flow distribution to Grashof numbers ranging from 2 to 200 is also discussed as is the influence of Hartmann number
on the bulk temperature. Rayleigh flow is demonstrated to become stable with respect to the width of the boundary layer region
and intensifies with greater magnetic field i.e. larger Hartman number M, for constant buoyant diffusivity parameter ϑ
*. The induced magnetic field (B
x
), is elevated in the vicinity of the plate surface with a rise in free convection (buoyancy) parameter G
r
, but is reduced over the central zone of the boundary layer regime. Applications of the study include laminar magneto-aerodynamics,
materials processing and MHD propulsion thermo-fluid dynamics. 相似文献
110.
YIN Xue-feng~ 《高等学校化学研究》2001,17(3):264-270
The suitability of 1-nitroso-2-naphthol(NN) as a complexing agent for on-line preconcentration of cobalt eluted on the C_(18) microcolumn by means of the FI-FAAS system was tested. Various parameters affecting the complex formation and its elution were optimized. A 2.3×10~(-3) mol/L reagent solution and the aqueous sample solution acidified with 0.1% (volume fraction) nitric acid were on-line mixed (6.4 mL/min) on a reaction coil set at (65±1)℃ and flowed through the microcolumn for 30 s. The pH of the mixed solution was adjusted to 3—4 with HNO_3(1 mol/L) or NaOH(1 mol/L). The adsorbed complexes in the microcolumn were eluted into the nebulizer of FAAS in 10 s with ethanol acidified with 1% HNO_3(3.0 mL/min). A good precision(1.6% for 100μg/L Co(Ⅱ), n=10), a high enrichment factor 17.2, with detection limit (3σ) 3.2μg/L, and sample throughput (90 h~(-1)) were obtained. The method was applied to the certified reference materials(CRMs), NBS-362 and NBS-364, for the determination of cobalt and the results were in good agreement with the certified values. 相似文献