• Proceedings of the Korean Society of Medical Physics Conference
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• 2002.09a
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• pp.367-369
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• 2002

We have designed ramp profile excitation pulse based on the Shinnar-Le Roux (SLR) algorithm. The algorithm provides many advantages to pulse designers. The first advantage is the freedom of deciding the amplitudes, frequencies, and ripple sizes of stopband, passband, and transition band of pulse profile. The second advantage is the freedom of deciding the pulse phase, more specifically, minimum phase, linear phase, maximum phase, and any phase between them. The minimum phase pulse is the best choice in the case of 3D TOF, because it minimizes the echo time, which implies the best image quality in the same MR examination condition. In addition, the half echo technique is slightly modified in our case. In general, using the half echo technique means that the acquired data size is half and the rest part can be filled with complex conjugate of acquired data. But in our case, the echo center is just shifted to left, which implies the reduction of echo time, and the acquired data size is the same as the one without using the half echo technique. In this case, the increase of right part of data leads to improvement of the resolution and the decrease of left part of data leads to decrease of signal to noise ratio. Since in the case of 3D TOF, the signal to noise ratio is sufficiently high and the resolution is more important than signal to noise ratio, the proposed method appears to be significantly affective and gives rise to the improved high resolution angiograms.

• Journal of the Institute of Electronics Engineers of Korea SP
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• v.38 no.6
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• pp.684-691
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• 2001

In this paper, we design and implement a system which recognizes and tracks a human head on a sequence of images. In this paper, the color of the skin and ellipse modeling is used as feature vectors to recognize the human head. And the modified time-varying edge detection method and the vertical projection method is used to acquire regions of the motion from images with very complex backgrounds. To select the head from the acquired candidate regions, the process for thresholding on the basis of the I-component of YIQ color information and mapping with ellipse modeling is used. The designed system shows an excellent performance in the cases of the rotated heads, occluded heads, and tilted heads as well as in the case of the normal up-right heads. And in this paper, the combinational technique of motion-based tracking and recognition-based tracking is used to track the human head exactly even though the human head moves fast.

• Journal of the Korean Institute of Gas
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• v.4 no.4 s.12
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• pp.42-49
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• 2000

Due to their size and complexity, it is very difficult to make diagnostic system for the whole chemical processes. Therefore, a systematic approach is required to decompose larpge-scale process into sub-processes and then diagnose them. This paper suggests a method for the minimization of knowledge base and flexible diagnosis to be used in qualitative fault diagnosis based on Fault-Effect Tree model. The system can be decomposed for flexible diagnosis, size reduction of knowledge base, and consistent construction of complex knowledge base. The new node, gate-variable, is introduced to connect the cause-effect relationships of each sub-process. For on-line diagnosis, off-line analysis is performed to construct Fault-Effect Trees of gate-variables as well as activation conditions of gate-variables. On-line diagnosis strategy is modified to get the same diagnosis result without system decomposition. The proposed method is illustrated with a fault diagnosis system for a large-scale boiler plant.

• The Journal of the Acoustical Society of Korea
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• v.32 no.3
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• pp.208-213
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• 2013

To get vibration responses, a camshaft is modelled as an unbalanced multiple rotor bearing system. Because of complex geometry and complicated load conditions, the finite element method is used. After the finite element equation of the system is constructed, Newmark's method is used to get the vibration responses. Whirl vibration responses of a V-8 engine camshaft are estimated and compared with measured responses. After the fluctuating stresses are obtained, fatigue analysis is performed based upon the modified Goodman's equation. Stress concentration effects are considered. In the whirl vibration of camshafts, the bending effect is dominant, and the bending deformation is dependent upon the span length between the adjacent bearing journals. For high speeds, the fluctuations of excitation forces are large, and it is known that nonlinear time varying bearing coefficients should be used for analysis.

• The Plant Pathology Journal
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• v.27 no.1
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• pp.59-67
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• 2011

A bacterial strain CH-67 which exhibits antagonism towards several plant pathogenic fungi such as Botrytis cinerea, Fulvia fulva, Rhizoctonia solani, Sclerotinia sclerotiorum, Colletotrichum sp. and Phytophthora sp. was isolated from forest soil by a chitin-baiting method. This strain was identified as Burkholderia cepacia complex (Bcc) and belonging to genomovar IX (Burkholderia pyrrocinia) by colony morphology, biochemical traits and molecular method like 16S rRNA and recA gene analysis. This strain was used to develop a bio-fungicide for the control of tomato leaf mold caused by Fulvia fulva. Various formulations of B. pyrrocinia CH-67 were prepared using fermentation cultures of the bacterium in rice oil medium. The result of pot experiments led to selection of the wettable powder formulation CH67-C containing modified starch as the best formulation for the control of tomato leaf mold. CH67-C, at 100-fold dilution, showed a control value of 85% against tomato leaf mold. Its disease control efficacy was not significantly different from that of the chemical fungicide triflumidazole. B. pyrrocinia CH-67 was also effective in controlling damping-off caused by Rhizoctonia solani PY-1 in crisphead lettuce and tomato plants. CH67-C formulation was recognized as a cell-free formulation since B. pyrrocinia CH-67 was all lethal during formulation process. This study provides an effective biocontrol formulation of biofungicide using B. pyrrocinia CH-67 to control tomato leaf mold and damping-off crisphead lettuce and tomato.

• Analytical Science and Technology
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• v.30 no.6
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• pp.405-410
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• 2017

High energetic materials (HEMs) have been used in fuels, civil engineering and architecture as well as military purposes such as explosives and propellants. The essential process for the development of new energetic compounds is to accurately calculate its detonation performances. The most typical equation for calculating the explosive performance is the Kamlet-Jacobs (K-J) equation. In the K-J equation, the parameter such as the number of moles of gaseous products at the explosion, the average molar mass of gas products, and the explosion heat greatly affect the explosion performance. These depend on the product composition for the detonation reaction. In this study, detonation products of 65 high energetic molecules (HEMs) were calculated from the various rules such as Kamlet-Jacobs, Kistiakowsky-Wilson, modified Kistiakowsky-Wilson, Springall-Roberts rules to calculate more accurate detonation velocity (Dv). In addition, they were applied to five kinds of detonation velocity equations proposed by K-J, Rothstein, Xiong, Stine and Keshavarz. The mean absolute error and root mean square error of HEMs were obtained from experimental and calculated velocity value for each method. The K-J and Xiong equation that is slightly complex showed a lower mean absolute error than the simple Rothstein and Keshavarz equation. When the mod-KW rule was applied to the Xiong equation, the detonation velocities were the most accurate. This study compared the various method of calculating the detonation velocity of HEMs to obtain accurate HEMs performance.

• Applied Biological Chemistry
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• v.29 no.1
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• pp.51-56
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• 1986

Using milled barley of four varieties Olbori, Youngsan-bori, Sacheon 6, and Suwon 228, the barley proteins were fractionated by the Osborne method and the modified Osborne method. Two fractionation methods were compared. There was a steady increase in the amount of nitrogen extracted as NaCl concentration increased, reaching a maximum at 0.5M NaCl and the extraction of nitrogen by 0.5M NaCl reached a maximum at $22^{\circ}C$. Alcohol-soluble fraction was least extracted by 70% (v/v) ethanol at $4^{\circ}C$ and most by sequential extraction with 50% (v/v) propan-1-ol alone followed by 50% (v/v) propan-1-ol plus 3% (v/v) 2-mercaptoethanol. Nitrogen was least extracted between pH 4 and 6 and most extracted at higher pH than 10. The modified Osborne fractionation of the protein complex in the four barleys showed that the salt-soluble nitrogen accounted for 21,4% to 24.1%, hordein-I varied from 30.4% to 43.4%, hordein-II varied widely from 9.3% to 19.5% and borate buffer-soluble glutelin content ranged from 17.1% to 23.7%.

• Journal of the Society of Cosmetic Scientists of Korea
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• v.42 no.1
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• pp.65-73
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• 2016

Korea Food and Drug Administration (KFDA) has officially announced 2,4-dinitrophenylhydrazine (DNPH) derivatization - high performance liquid chromatography (HPLC) methods for analysis of formaldehyde. This study was conducted to develop a convenient derivatization method for cosmetics by improving complex pre-treatment procedures included in KFDA method. To simplify pre-treatment procedures of KFDA method, reaction conditions including pH, time and temperature were optimized. This pre-treatment method does not require complicate pre-treatment steps of KFDA method such as pH adjustment of test solution with acetate buffer (pH 5.0), solvent-solvent partitioning with dichloromethane and concentrating procedure with vacuum evaporator. Formaldehyde-dinitrophenylhydrazone (formaldehyde-DNP) product produced by derivatization reaction was separated and quantified with a reversed-phase HPLC, which was slightly modified with KFDA method. The linearity test showed good results with 0.9999 of correlation coefficient ($r^2$) in the range of 2 ~ 40 ppm of standard solutions. In this method, limit of detection (LOD) and limit of quantitation (LOQ) values for formaldehyde were 0.2 ppm and 0.5 ppm, respectively. In addition, recovery test demonstrated that the method was also accurate and reproducible. Therefore, the proposed method can be applicable to rapid analysis of formaldehyde in cosmetics.

• Journal of Adhesion and Interface
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• v.24 no.4
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• pp.136-142
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• 2023

In this study, TEOS was used as a silica source, and a triblock copolymer (P123) was used as a template to produce mesoporous silica with a well-ordered hexagonal mesopore array through a self-assembly method and hydrothermal process under acidic condition. (Surfactant-extracted SBA-15). Surfactant-extracted SBA-15 showed the particle shape of a short rod with a size of approximately 980 nm. The surface area and pore diameter were 730 m²g^-1 and 70.8 Å, respectively. Meanwhile, aminosilane (3-aminopropyltriethoxysilane, APTES) was grafted into the mesopores using a post-synthesis method. Mesoporous silica (APTES-SBA-15) modified with aminosilane had a well-ordered pore structure (p6mm) and well-maintained the particle shape of short rods. The surface area and pore diameter of APTES-SBA-15 decreased to 350 m²g^-1 and 60.7 Å, respectively. APTES-modified mesoporous silica was treated with a solution of rare earth metal ions (Eu³⁺, Tb³⁺) to synthesize a mesoporous silica material in which rare earth metal complexes were introduced into the mesopores. (Eu/APTES-SBA-15, Tb/APTES-SBA-15) These materials exhibited characteristic photoluminescence spectra by λ_ex=250 nm. (⁵D₄→⁷F₅ (543.5 nm), ⁵D₄→⁷F₄ (583.5 nm), ⁵D₄→⁷F₃ (620.2 nm) transitions for Tb/APTES-SBA-15; ⁵D₀→⁷F₀ (577.7 nm), ⁵D₀→⁷F₁ (592.0 nm), ⁵D₀→⁷F₂ (614.9 nm), ⁵D₀→⁷F₃ (650.3 nm) and ⁵D₀→⁷F₄ (698.5 nm) transitions for Eu/APTES-SBA-15)

• The Transactions of the Korean Institute of Power Electronics
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• v.7 no.2
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• pp.205-213
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• 2002

This paper deals with the implementation of three-phase VSI systems which can control the power regenerated from DC bus line to AC supply. The overall system consists of the line-to-line voltage and line current sensors, an actual power calculator using d-q transformation method, a complex power controller with PI control scheme, a gating signal generator for modified ｑ-conduction mode, a DPLL for frequency followup, and Power circuits. Control board is constructed by using a 32-bit DSP TMS32C32, two EFLDs , six ADCs, and a DAC. To verify the performance of the proposed system, we designed and constructed the propotype with the power rating of 5kVA at AC 220V. Experimental results show that the regenerated active power is well controlled to its command vague and the regenerated reactive power still remained at nearly zero through all operating modes.