• Journal of Magnetics
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• v.20 no.2
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• pp.110-113
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• 2015

Two kinds of magnetic fluids with different volume fractions are symmetrically filled into the W0.9 photonic crystal waveguide structure. The 2D plane-wave expansion method is used to investigate the slow light properties numerically. The constant group index criterion is employed to evaluate the slow light performance. The wavelength bandwidth ${\Delta}{\lambda}$ centering at ${\lambda}_0=1550nm$ varies from 32.4 to 44.2 nm when the magnetic field factor ${\alpha}_{\parallel}$ changes from 0 to 1. And the corresponding normalized delay bandwidth product can be tuned from 0.221 to 0.258. For comparison and optimization, two infiltration cases are investigated and the more advantageous infiltration scheme is found.

• Analytical Science and Technology
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• v.8 no.4
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• pp.843-848
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• 1995

A sensitive method for the determination of trace amounts of phosphate by fluorescence-quenching detection / FIA is proposed. The fluorescence of Rhodamine B(RB) was quenched with the formation of the ion associate of molybdophosphate with RB;${\lambda}_{ex}$ and ${\lambda}_{em}$ were 560nm and 580nm, respectively. A calibration graph was linear over the ranges from $10^{-8}$ to $3{\times}10^{-6}M$ of phosphate (~0.3~93ppb of phosphorus). The relative standard deviation was 1.2% with $8{\times}10^{-7}M$ phosphate solution and sampling rate was 15 samples / h. The proposed method was applied to the determination of phosphate in sea and river water samples.

• Journal of the Korean Society of Fisheries and Ocean Technology
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• v.40 no.4
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• pp.360-366
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• 2004

This paper presents a method analyzing the motion of cylindrical buoy moored at 2 points and tensions action on each mooring line under the action of periodic waves. It was found that submersible buoy was more effective than floating one in the severe conditions considering its dynamic motions, wave forces, and mooring line tensions. The wave induced its dynamic responses and mooring line tensions peak when the ratio d/${\lambda}$ of the buoy length d to the waves length ${\lambda}$ was 0.66 due to its natural frequency. The results of this study were in agreement with the existing measurement ones, however, further verifications are needed considering resonance of cylindrical buoy and its displacements to wave height by a series of model tests.

• The Proceeding of the Korean Institute of Electromagnetic Engineering and Science
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• v.6 no.3
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• pp.3-14
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• 1995

The broadband input impedance, the input power and the radiation pattern of the monopole antenna attached to the handy phone operated at 800MHz are calculated by using the Finite Difference Time Domain(FDTD) Method. For the FDTD analysis of frequency characteristics of monopole antenna, the handy phone is modeled with the geometry that the monopole antenna is connected to a conducting box, and the modified FDTD algorithm[11] used the thin wire appproximation method and the Maxwell's integral equation from the original Yee algorithm is applied for the analysis of the wire structure. Also, by means of finding the current distribution directly from circumferencial magnetic filelds around the monopole antenna and the conducting box, the radiation pattern is calculated to observe the influence of the conducting box, and is compared with the results of the known mothod for the FDTD calculation of radiation pattern, For the experiments, the handy phone of which full length including antenna is .lambda. $\lambda$/2 is manufactured and we confirm that all computation results are agree well with the mea- sured values.

• Journal of applied mathematics & informatics
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• v.32 no.1_2
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• pp.113-128
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• 2014

Consider a class of p(x)-Kirchhoff type equations of the form $$\left\{-M\left({\int}_{\Omega}\;\frac{1}{p(x)}{\mid}{\nabla}u{\mid}^{p(x)}\;dx\right)\;div\;({\mid}{\nabla}u{\mid}^{p(x)-2}{\nabla}u)={\lambda}V(x){\mid}u{\mid}^{q(x)-2}u\;in\;{\Omega},\\u=0\;on\;{\partial}{\Omega},$$ where p(x), $q(x){\in}C({\bar{\Omega}})$ with 1 < $p^-\;:=inf_{\Omega}\;p(x){\leq}p^+\;:=sup_{\Omega}p(x)$ < N, $M:{\mathbb{R}}^+{\rightarrow}{\mathbb{R}}^+$ is a continuous function that may be degenerate at zero, ${\lambda}$ is a positive parameter. Using variational method, we obtain some existence and multiplicity results for such problem in two cases when the weight function V (x) may change sign or not.

• Journal of the Korean Vacuum Society
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• v.9 no.1
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• pp.48-59
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• 2000

Electrochromic NiO films were prepared by using an electron-beam deposition method. The influence of the preparation conditions, especially the substrate temperature, on the electrochemical stability of film was investigated. The optical properties and stability of as-deposited films strongly depended on the substrate temperature during deposition. The NiO film prepared at a substrate temperature of 150~$200^{\circ}C$ was found to be the stabel when subjected to 5000cycles in a 0.5M solution of KOH between -6.0 and +0.8V. The best electrochromic parameters after 5000cycles were obtained for samples with substrate temperature of $150^{\circ}C$. The obtained electrochromic parameters are CE=-0.049($\lambda$=550nm), $\Delta$OD=0.88($\lambda$=550nm)$\textrm{cm}^2$/mC, Qin=-18.11mC/$\textrm{cm}^2$ and Qleft= 14.8mC/$\textrm{cm}^2$.

• Transactions of the Korean Society of Mechanical Engineers
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• v.15 no.1
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• pp.120-126
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• 1991

An expanded scheme of a direct numerical solution method for solving the Navier-Stokes equation considering the modified boundary conditions for gas lubrication with ultra low clearance at high .LAMBDA. region is presented. Many examples are calculated by this scheme and their results are compared to the previous solutions using P$^{2}$H$^{[-992]}$ . This scheme has the advantages of fast calculation time and stable convergence in high .LAMBDA. region, and gives very good results in the case of fluid film thickness discontinuity.

• Journal of Advanced Marine Engineering and Technology
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• v.37 no.1
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• pp.105-113
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• 2013

In this work, using a ${\pi}$-type multiple coupled microstrip line structure (MCMLS) and RCR (Resistor Capacitor Resistor) structure, we fabricated ultra-compact and high isolation Wilkinson power divider on GaAs MMIC (Monolithic Microwave Integrated Circuit). The line length of the Wilkinson power divider was reduced to about ${\lambda}$/46, and its size was 0.304 [$mm^2$], which is 12.1 % of conventional one. Compared with conventional Wilkinson power divider, isolation characteristic of the proposed Wilkinson power divider was highly improved by using RCR insertion method. The proposed Wilkinson power divider showed good RF performances in C/X band.

• Journal of the Korea Society for Simulation
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• v.24 no.3
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• pp.27-35
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• 2015

We analyze an M/G/1/K queueing system with queue-length dependent service and arrival rates. There are a single server and a buffer with finite capacity K including a customer in service. The customers are served by a first-come-first-service basis. We put two thresholds $L_1$ and $L_2$($${\geq_-}L_1$$ ) on the buffer. If the queue length at the service initiation epoch is less than the threshold $L_1$, the service time of customers follows $S_1$ with a mean of ${\mu}_1$ and the arrival of customers follows a Poisson process with a rate of ${\lambda}_1$. When the queue length at the service initiation epoch is equal to or greater than $L_1$ and less than $L_2$, the service time is changed to $S_2$ with a mean of $${\mu}_2{\geq_-}{\mu}_1$$. The arrival rate is still ${\lambda}_1$. Finally, if the queue length at the service initiation epoch is greater than $L_2$, the arrival rate of customers are also changed to a value of $${\lambda}_2({\leq_-}{\lambda}_1)$$ and the mean of the service times is ${\mu}_2$. By using the embedded Markov chain method, we derive queue length distribution at departure epochs. We also obtain the queue length distribution at an arbitrary time by the supplementary variable method. Finally, performance measures such as loss probability and mean waiting time are presented.

• Journal of the Korean Geosynthetics Society
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• v.15 no.2
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• pp.1-12
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• 2016

In this study, laboratory mixture design test and field test were performed to evaluate applicability of eco-friendly binder material (CMD-SOIL) using desulfurized dust in deep cement mixing method (DCM). As a result of laboratory mixture design test, the uniaxial compressive strength of CMD-SOIL was up to 1.136 times bigger than slag cement by changing the water content, mixing rate, and W/B. Also, it had shown the strength up to 1.222 times bigger in shell content and up to 1.363 times in mixing of floating soil. As a result of field test, field strength/laboratory design criterion strength ratio (${\lambda}$) is shown 0.77. And this result was similar to earlier studies. From this result, CMD-SOIL can show the same efficiency compared with existing binder.