• Journal of applied mathematics & informatics
• /
• v.28 no.5_6
• /
• pp.1101-1116
• /
• 2010

The aim of this paper is to give some simultaneous approximation properties as well as differential properties, Voronovskaya type theorem, several asymptotic formulae for the partial derivative and the degree of approximation for two dimensional Lupas type operators.

• Journal of applied mathematics & informatics
• /
• v.40 no.5_6
• /
• pp.1117-1128
• /
• 2022

We find several q-differential equations of higher order that has q-tangent polynomials as the solution and obtain its associated symmetric properties.

• Bulletin of the Korean Chemical Society
• /
• v.33 no.11
• /
• pp.3740-3744
• /
• 2012

We synthesized three different derivatives of bis-spiropyran using simple organic reactions with high yields. BSP1, a derivative of bis-spiropyran having a connection at the position 6' and BSP2, a derivative of bis-spiropyran having a connection at the position 5 and BSP3, a derivative of bis-spiropyran containing a dithienylethene group between two spiropyran moieties were synthesized. The optical properties of BSPs were characterized. UV-Vis spectra showed that BSPs exhibit reversible photo-isomerization and the efficiency of photo-isomerization is highly dependent on the position of nitro group. BSPs having nitro group at para position of hydroxy group showed the higher efficiency of photo-isomerization that the one having nitro group at ortho position. The optical microscope images obtained under ultraviolet or visible light exposure demonstrated that the formation of nanorods can be reversibly controlled by optical signal.

• Bulletin of the Korean Chemical Society
• /
• v.28 no.3
• /
• pp.471-473
• /
• 2007

• Journal for History of Mathematics
• /
• v.27 no.5
• /
• pp.329-345
• /
• 2014

CAGD(Computer Aided Geometric Design) is a branch of applied mathematics concerned with algorithms for the design of smooth curves and surfaces and for their efficient mathematical representation. The representation is used for the computation of the curves and surfaces, as well as geometrical quantities of importance such as curvatures, intersection curves between two surfaces and offset surfaces. The $B\acute{e}zier$ curves, B-spline, rational $B\acute{e}zier$ curves and NURBS(Non-Uniform Rational B-Spline) are basically and widely used in CAGD. The definitions and properties of these curves are presented in this paper. And a brief history of study on the bound for derivative of rational curves in CAGD is also presented.

• Food Science and Biotechnology
• /
• v.17 no.3
• /
• pp.683-686
• /
• 2008

$\beta$-Glucans, which were isolated from sangwhang (Phellinus linteus), were subjected to reductive amination and the biological properties of the derivative were investigated. The degree of substitution of the aminated sangwhang $\beta$-glucan was calculated by elemental analysis to be 1.13. Bronchoalveolar lavage (BAL) experiments showed that the aminated derivative increased nitric oxide production. In addition, the amination enhanced in vitro cytotoxic activities against HT1080 and SNU-C2A cell lines. Thus, the aminated derivative is shown to enhance immune systems by the incorporation of amino groups into the polymer structure.

• Journal of applied mathematics & informatics
• /
• v.26 no.5_6
• /
• pp.1101-1121
• /
• 2008

One proposes an approach to fractional Fourier's transform, or Fourier's transform of fractional order, which applies to functions which are fractional differentiable but are not necessarily differentiable, in such a manner that they cannot be analyzed by using the so-called Caputo-Djrbashian fractional derivative. Firstly, as a preliminary, one defines fractional sine and cosine functions, therefore one obtains Fourier's series of fractional order. Then one defines the fractional Fourier's transform. The main properties of this fractal transformation are exhibited, the Parseval equation is obtained as well as the fractional Fourier inversion theorem. The prospect of application for this new tool is the spectral density analysis of signals, in signal processing, and the analysis of some partial differential equations of fractional order.

• Macromolecular Research
• /
• v.14 no.4
• /
• pp.443-448
• /
• 2006

A novel ${\beta}$-cyclodextrin derivative (CCD-C) was synthesized with chitosan and carboxymethyl-${\beta}$-cyclodextrin. Its structure was characterized by elemental analysis, infrared spectra analysis, and X-ray diffraction analysis. The adsorption properties for guanosine 5'-monophosphate, cytidine 5'-monophosphate and uridine 5'-monophosphate were studied. Experimental results demonstrated that CCD-C had higher adsorption capability for guanosine 5'-monophosphate, and that the adsorption capacity for guanosine 5'-monophosphate was 74.20mg/g. The adsorption capacity was greatly influenced by pH, time and temperature. The introduction of chitosan enhanced the adsorption ability and adsorption selectivity of ${\beta}$-cyclodextrin for guanosine 5'-monophosphate. This novel derivative of chitosan is expected to have wide applications in the separation, concentration and analysis of nucleotides in biological samples.

• Proceedings of the Korea Concrete Institute Conference
• /
• 2005.05b
• /
• pp.45-48
• /
• 2005

Self compacting concrete has the strong point in capability of concrete to be uniformly filled and compacted in every corners of formwork by its self-weight without vibration during placing. However, powder type self compacting concrete has the weak point in the heat of hydration, the drying shrinkage and the elastic property of concrete etc. Recently viscosity agent has been developed in order to overcome these weaknesses. In this study, self compacting concrete is made with viscosity agent based on polysaccharide derivative in order to develope the normal strength self compacting concrete. Slump flow, loss of slump flow and setting time are measured for comparison with normal concrete. Compressive strength, freezing and thawing test and carbonation test are conducted on normal and self compacting concrete using viscosity agent. In the experiment, we acquired good results in fresh and hardened self compacting concrete using viscosity agent based on polysaccharide derivative.

• Communications of the Korean Mathematical Society
• /
• v.29 no.1
• /
• pp.51-63
• /
• 2014

In the paper, several properties of geometric-arithmetically s-convex functions are provided, an integral identity in which the integrands are products of a function and a derivative is found, and then some inequalities of Hermite-Hadamard type for integrals whose integrands are products of a derivative and a function whose derivative is of the geometric-arithmetic s-convexity are established.