• Korean Chemical Engineering Research
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• v.54 no.4
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• pp.487-493
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• 2016

The moment analysis of lysozyme was implemented using chromatograms that were obtained from weak cation exchange column in high performance liquid chromatography system. Three elution sodium phosphate buffers containing 1.0, 0.75, 0.5M sodium chloride were used. Experiments were conducted by varying flow rate, elution sodium chloride concentration, and lysozyme solute concentration. The general rate (GR) model was employed to calculate the first moment and the second moment. By plotting $L/u_0$ vs. $({\mu}_1-t_0)/(1-{\varepsilon}_e)(1-{\varepsilon}_i)$] equilibrium constants (K) were obtained from first moment analysis. Intra-particle diffusivity was obtained from theoretical plate number data. Based on the results of moment analysis, van Deemter plots were drawn in order to investigate the contributions of $H_{ax}$, $H_f$, and $H_d$ to total Height Equivalent to a Theoretical Plate (HETP, $H_{total}$). The effect of intra-particle diffusion ($H_d$) was the most dominant factor contributing to HETP while external mass transfer ($H_f$) was negligible factor.

• Korean Journal of Microbiology
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• v.28 no.4
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• pp.345-350
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• 1990

In order to ferment D-xylose directly to ethanol, Yeasts capable of utilizing D-xylose as a sole carbon source and energy source were isolated from soil, sawdust and rotten woods. Among them, the yeast strain, which showed the best ability to produce ethanol, was identified as Candida sp. L-16 isolated from rotten woods. The optimal conditions for production of ethanol were 60rpm of agitation speed, 28j.deg.C of temperature, 4.5 of initial pH and 5% of D-xylose concentration. Ethanol production was reached to maximum state for 4 days culture. Under these optimal conditions, the maximum ethanol concentration and theoretical ethanol yield were 2.4%(v/v) and 74.4% of theoretical value, respectively.

• Journal of the Korean Chemical Society
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• v.45 no.5
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• pp.401-412
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• 2001

The geometrical parameters, vibrational frequencies, and dissociation energies for $H_{2n+1}^+$ (n=1~6) clusters have been investigated using high level ab initio quantum mechanical techniques with large basis sets. The equilibrium geometries have been optimized at the self-consistent field (SCF), the single and double excitation configuration interaction (CISD), the coupled cluster with single and double excitation (CCSD), and the CCSD with connected triple excitations [CCSD(T)] levels of theory. The highest levels of theory employed in this study are TZ2P+d CCSD(T) up to $H^+_g$ and TZ2P CCSD(T) for $H_{11}^+$ and $H_{13}^+$. Harmonic vibrational frequencies are also determined at the SCF level of theory with various basis sets and confirm that all the optimized geometries are true minima. The dissociation energies, $D_e$, for $H_{2n+1}^+$ (n=26) have been predicted using energy differences at each optimized geometry and zero-point vibrational energies(ZPVEs) have been considered to compare with experimental dissociation energies, $D_0$.

• Journal of the Korean Institute of Gas
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• v.19 no.5
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• pp.104-111
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• 2015

The technology development of pipeline transportation of natural gas at artic and northern ice environments should be considered with unique characteristics of permafrost territory as a very interesting and challenging area. This work is to investigate bottleneck techniques and major impact factors through a literature search to figure out the core technology of the transport pipeline. Especially, theoretical approach themes could be determined to develop the technology flow assurance for permafrost regions through documentary survey on the considerations of thermo-fluid. Also, basic results through theoretical approaches could be achieved.

• Journal of IKEEE
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• v.17 no.3
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• pp.385-392
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• 2013

In this paper, microstrip antenna to enhance the isolation between transmitting port and receiving port under the proximity objects is proposed, and applied to the Doppler radar sensor working at 5.8GHz ISM band which detects vital signals of a human body. Two 3dB quadrature hybrids are placed around radiation patch to form a balanced structure between transmitting port and receiving port, such that it consistently provides enhanced Tx/Rx isolation and excellent return loss over nearby objects. It is theoretically analyzed and simulated to verify the validity of the proposed application. The fabricated antenna that is 2mm away from the human body, has more than 16 dB return loss and at least 30dB isolation over ISM frequency band of 5.8GHz.

• The Journal of Korean Institute of Electromagnetic Engineering and Science
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• v.21 no.4
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• pp.408-416
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• 2010

A study on the calibration of an X-band HPS(Hongik Polarimetric Scatterometer) system for ground-based operation is presented in this paper. In order to calibrate the scatterometer system, the degree of its distortions are analyzed by comparison between theoretical- and measured-values using the theoretically well-known calibration targets such as a metal sphere, a trihedral corner reflector(CR) and a metal cylinder. The calibration works in the field conditions depend on the precise and stable measurements of those calibration target. we present a measurement technique, so-called, an automatic 2-D target-scanning technique, using the incidence-angle(${\xi}-$ and ${\phi}-$ directions) control of HPS system. Then, we used STCT(Single-Target Calibration Technique) and GCT(General Calibration Technique) to calibrate a distortion of the scatterometer system, and measured the polarimetric RCS(Radar Cross Section) and phase-difference of a trihedral-CR as a test-target to verify the accuracy of the calibration technique. Then, three different types(i.e., 10, 20, 30 cm) of trihedral-CR were used. we obtained the error ranges about ${\pm}1.0$dB, ${\pm}0.5$ dB in a polarimetric RCS and about $-20^{\circ}{\sim}0^{\circ}$ and ${\pm}5^{\circ}$ in the co-polarized phase-difference by using the GCT and STCT, respectively.

• Proceedings of the Korea Water Resources Association Conference
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• 2006.05a
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• pp.1037-1041
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• 2006

본 연구에서는 수질자료에 내재되어 있는 주기성 및 경향성 등을 파악하기 위해 웨이블렛 변환을 적용하였으며 비선형 시계열자료에 대한 예측력이 우수한 인공신경망을 적용하여 예측모형을 개발하였다. 대상자료는 섬진강 유역의 주암호 수질자동측정망 지점에서 측정되고 있는 수질자료 중 2002년 1월 1일 ${\sim}$ 2004년 12월 31일까지의 일 TOC 수질자료를 이용하였다. 웨이블렛 변환을 위해 사용한 기저함수로는 Daubechies의 10번 웨이블렛 함수('db10')를 사용하였으며, 각 스케일링 및 웨이블렛 함수를 이용하여 5단계까지 변환하였다. 최종 변환된 근사성분과 D5, D4, D3, D2의 상세성분 자료를 이용하여 1시간후 TOC 예측 모형을 구성하였으며 그 결과 은닉층의 노드의 수가 17개인 모형인 Model_5_17 모형이 가장 우수한 예측력을 보였다.

• Journal of the Korean Institute of Telematics and Electronics
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• v.26 no.5
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• pp.32-37
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• 1989

The design method of the center-fed resonant type slotted waveguide antenna using the Dolph-Tschebyscheff array is presented. Slot admittances are obtained by empirical and theoretical method since the effect of mutual coupling between slots is included. We design a slotted waveguide antenna which has 1.8ft. length and operates on 9.4GHz. The experimental results of the antenna show that its gain, maximum sidelobe level and half power beam-width are 25.5dB, -22dB and 3.6deg., respectively.

• The Transactions of the Korean Institute of Electrical Engineers C
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• v.53 no.11
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• pp.577-582
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• 2004

In this paper, lumped equivalent circuits for a conventional parallel directional coupler are proposed. This equivalent circuits only have self inductance and self capacitance, so we can design exact lumped equivalent circuit. The equivalent circuit and design formula for the presented lumped element coupler is derived based on the even- and odd-mode properties of parallel-coupled line. By using the derived design formula, we have designed the 3dB and 4.7dB MMIC couplers at the center frequency of 3.4GHz and 5.6GHz respectively. Measurements for the designed MMIC directional couplers show at 4dB and 5.2dB-coupling value at the center frequency of 3.4GHz and 5.6GHz. Excellent agreements between simulation results and measurement results on the designed directional couplers show the validity of this paper

• Transactions of the Korean Society of Mechanical Engineers A
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• v.40 no.8
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• pp.711-719
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• 2016

In this study, we derived an theoretical equation, using a simplified spring-mass model for the rolling stock, to obtain the overriding behavior of a leading vehicle, which is considered as the main factor in train accidents. To verify the derived equation, we created a simple 2D model based on the theoretical model, and a simple 3D model considering the characteristics of the power bogie. We then compared the theoretical results with the simulation results obtained using LS-DYNA. The maximum relative derivations in the vertical displacements at the first end-buffer, which is the most important point in overriding, were 3.5 [%] and 1.7 [%] between the two results. Further, we evaluated collision-induced overriding displacements using the theoretical equation for a rubber draft gear, a hydraulic buffer under various collision conditions. We have suggested a theoretical approach for the realization of overriding collision accidents or the energy absorption design of the front end of trains.