• Journal of the Korean Ceramic Society
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• v.30 no.11
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• pp.897-904
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• 1993

CdS doped SiO2 glass coating films which are good candidates for the nonlinear optical materials were prepared by the Sol-Gel method. TEOS, C2H5OH, H2O and HCl were used as starting materials to obtain SiO2 matrix solutions. Then Cd(NO3)2.2H2O and CS(NH2)2 were dissolved into the SiO2 matrix solutions. Coating was performed several times in order to increase the thickness of coated film by the dip-coating method. Then heat treatments were carried out to control the size of CdS microcrystals doped in SiO2 glass matrix with respect to temperatures and times. CdS-doped SiO2 transparent coating films were successfully obtained. CdS crystals were changed from cubic to hexagonal type about $600^{\circ}C$.

• The Journal of Korean Institute of Communications and Information Sciences
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• v.22 no.11
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• pp.2512-2520
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• 1997

The classes of Reverse Jacket matrix [RJ]$_{N}$ and the corresponding Restclass Reverse Jacket matrix ([RRJ]$_{N}$) are defined;the main property of [RJ]$_{N}$ is that the inverse matrices of them can be obtained very easily and have a special structure. [RJ]$_{N}$ is derived from the weighted hadamard Transform corresponding to hadamard matrix [H]$_{N}$ and a basic symmertric matrix D. the classes of [RJ]$_{2}$ can be used as a generalize Quincunx subsampling matrix and serveral polygonal subsampling matrices. In this paper, we will present in particular the systematical block-wise extending-method for {RJ]$_{N}$. We have deduced a new orthorgonal matrix $M_{1}$.mem.[RRJ]$_{N}$ from a nonorthogonal matrix $M_{O}$.mem.[RJ]$_{N}$. These matrices can be used to develop efficient algorithms in IMT2000 signal processing, multidimensional subsampling, spectrum analyzers, and signal screamblers, as well as in speech and image signal processing.gnal processing.g.

• 한국초전도학회:학술대회논문집
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• 2009.07a
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• pp.123-123
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• 2009

• Journal of the Institute of Electronics and Information Engineers
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• v.49 no.10
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• pp.181-186
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• 2012

In this paper, we describe the synthesis of robust and non-fragile Kalman filter design for a class of uncertain linear system with polytopic uncertainties and filter gain variations. The sufficient condition of filter existence, the design method of robust non-fragile filter, and the measure of non-fragility in filter are presented via LMIs(Linear Matrix Inequality) technique. And the obtained sufficient condition can be represented as PLMIs(parameterized linear matrix inequalities) that is, coefficients of LMIs are functions of a parameter confined to a compact set. Since PLMIs generate infinite LMIs, we use relaxation technique, find the finite solution for robust non-fragile filter, and show that the resulting filter guarantees the asymptotic stability with parameter uncertainties and filter fragility. Finally, a numerical example will be shown.

• Communications for Statistical Applications and Methods
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• v.12 no.3
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• pp.653-657
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• 2005

Eigenstructure of a spatial design matrix of Matheron's variogram estimator in $R^1$ is derived. It is shown that the spatial design matrix in $R^1$ with n/2$\le$h < n has a nice spectral decomposition. The mean, variance, and covariance of this estimator are obtained using the eigenvalues of a spatial design matrix. We also found that the lower bound and the upper bound of the normalized Matheron's variogram estimator.

• Kyungpook Mathematical Journal
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• v.59 no.2
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• pp.233-240
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• 2019

In the present paper, absolute matrix summability of infinite series is studied. A new theorem concerning absolute matrix summability factors, which generalizes a known theorem dealing with absolute Riesz summability factors of infinite series, is proved using almost increasing and ${\delta}$-quasi-monotone sequences. Also, a result dealing with absolute $Ces{\grave{a}}ro$ summability is given.

• Advanced Composite Materials
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• v.18 no.4
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• pp.351-364
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• 2009

The thermal stability and elevated temperature mechanical properties of $SiC_P$/Al-11.7Fe-1.3V-1.7Si (Al-11.7Fe-1.3V-1.7Si reinforced with SiC particulates) composites sheets prepared by spray deposition (SD) $\rightarrow$ hot pressing $\rightarrow$ rolling process were investigated. The experimental results showed that the composite possessed high ${\sigma}_b$ (elevated temperature tensile strength), for instance, ${\sigma}_b$ was 315.8 MPa, which was tested at $315^{\circ}C$, meanwhile the figure was 232.6 MPa tested at $400^{\circ}C$, and the elongations were 2.5% and 1.4%, respectively. Furthermore, the composite sheets exhibited excellent thermal stability: the hardness showed no significant decline after annealing at $550^{\circ}C$ for 200 h or at $600^{\circ}C$ for 10 h. The good elevated temperature mechanical properties and excellent thermal stability should mainly be attributed to the formation of spherical ${\alpha}-Al_{12}(Fe,\;V)_3Si$ dispersed phase particulates in the aluminum matrix. Furthermore, the addition of SiC particles into the alloy is another important factor, which the following properties are responsible for. The resultant Si of the reaction between Al matrix and SiC particles diffused into Al matrix can stabilize ${\alpha}-Al_{12}(Fe,\;V)_3Si$ dispersed phase; in addition, the interface (Si layer) improved the wettability of Al/$SiC_P$, hence, elevated the bonding between them. Furthermore, the fine $Al_4C_3$ phase also strengthened the matrix as a dispersion-strengthened phase. Meanwhile, load is transferred from Al matrix to SiC particles, which increased the cooling rate of the melt droplets and improved the solution strengthening and dispersion strengthening.

• Journal of Animal Science and Technology
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• v.62 no.4
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• pp.533-542
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• 2020

The objective of this study was to observe the interactions between salt-soluble proteins extracted from beef and elephant foot yam (Amorphophallus campanulatus) flour in heat-induced gel matrix development. The effect of salt concentration; 0.5%, 1.0%, 1.5%, and 2.0% in weight/weight basis (w/w), during protein extraction on pH, salt-soluble protein concentration and myofibril fractions of beef extract was determined firstly, and no significant effect was found. The beef salt-soluble proteins extracted using salt solution at different concentrations were then added with elephant foot yam flour at 5%, 10%, and 15% w/w, gelatinized at 90℃ for 20 min, and cooled down at 4℃ for 12 h. The interactions between beef salt-soluble proteins and elephant foot yam flour resulted in an improved gel strength (p < 0.01) and the addition level of elephant foot yam flour affected the pH, instrumental color, moisture, crude protein, and ash content significantly. The addition of elephant foot yam flour also reduced the size of the pores in the gel matrix as shown by scanning electron microscope (SEM) photographs. These suggest that elephant foot yam flour well interacts with beef salt-soluble proteins to form gel matrix.

• Transactions of the Korean Society for Noise and Vibration Engineering
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• v.14 no.12
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• pp.1330-1337
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• 2004

In this study, the equations of motion of a rigid rotor supported by magnetic bearings are derived via Hamilton's principle, and transformed to a state-space form for control purpose. The optimal motion control of rotor magnetic bearing system based on the LQR(linear quadratic regulator) theory is addressed. New schemes related to the selection of the state weighting matrix Q and the control weighting matrix R involved in the quadratic functional to be minimized are proposed. And the robust control of the system with an LMI(linear matrix inequality) based H$_{\infty}$ theory is dealt with in this paper. Loop shapings of TFM (transfer function matrix) are used to increase the performance of control capability of the system. The control abilities of LQR and H$_{\infty}$ controller are compared by simulation and experimental tests and show that the capability of H$_{\infty}$ controller is superior to that of LQR.

• Korean Journal of Materials Research
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• v.15 no.12
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• pp.809-813
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• 2005

A copper matrix composite reinforced by turbulent in-situ $TiB_2$ nanoparticle was Prepared by reactions of boron ana titanium. The microstructure, mechanical and electrical properties of the as-drawn composites were investigated. The results showed that the formed $TiB_2$ particles, which had a size of about from 50 to 200nm, exhibited a homogeneous dispersion in the copper matrix. Due to their reinforcement, the hardness and Young's modulus of $Cu-TiB_2$ composites were enhanced with increasing the cooling rate. Moreover, the electrical conductivity of the composites were improved with increasing the cooling rate.