• Computational Structural Engineering
• /
• v.9 no.2
• /
• pp.173-182
• /
• 1996

The present study proposes a detection technique for delaminations in a laminated compoiste structure. the proposed technique optimizes the spatial distribution of harmonic excitation so as to magnify the difference in response between the delaminated and intact structures. The technique is evaluated by numerical simulation of two-layered aluminum beams. Effects of measurement and geometric noises are included in the analysis. A finite element model for a delaminated beam, based on the layer-wise laminated plate theory in conjunction with a step function to simulate ddelaminations, is used.

• Korean Journal of Optics and Photonics
• /
• v.12 no.4
• /
• pp.320-326
• /
• 2001

In this paper, we have fabricated asymmetric Y-branch optical power splitters with various optical power splitting ratios by changing the width of one of the output waveguides using $Ag^+-Na^+$ ion change method in BK7 glass. The transmission characteristics of asymmetric Y-branch optical power splitters with different output waveguide width have been investigated using the finitedifference beam propagation method (FD-BPM). We have found the index of the channel waveguide formed by Ag+-Na+ ion change method in BK7 glass and have fabricated channel waveguides to examine the transmission characteristics of channel waveguide. And we have fabricated asymmetric Y-branch optical power splitters with output waveguide width from TEX>$4{\mu}m$ to $6{\mu}m$. /TEX>.

• Journal of Aquaculture
• /
• v.18 no.3
• /
• pp.142-146
• /
• 2005

In this study, the reattachment processes of small and medium size of spot of Mytilus coruscus and M. edulis were observed. The small spats (Shell length, SH, $3{\sim}7mm$) of hard shelled mussel, M. coruscus showed 100% reattachment rate within 7 minutes after the detachment of byssus thread and 100% survival rate. While large spats (SH 25 mm) showed 85% reattachment rate within 5 hours and 100% survival rate for 24 hours. The reattachment rate of M. edulis (SH 30 mm) was higher than that of M. coruscus (SH, 28 mm). The thread consisted of three identifiable structures; adhesive disc, adhesive thread and adhesive root. The adhesive disk and adhesive thread of M. coruscus were larger and thicker than those of M. edulis, whereas the thickness of adhesive root was the other way round. Further studies are required to identify the relationship between the structure of byssus thread and attachment ability. This study suggests that the sizes of spats could be an important factor in determining the timing of removing and reattaching mussel seedling for aquaculture or releasing to the sea.

• Journal of the Korean GEO-environmental Society
• /
• v.18 no.2
• /
• pp.53-58
• /
• 2017

In this paper, we propose a new method to debond between mixed finite elements for porous media in ABAQUS (2014). ABAQUS just provides debonding algorithm for the u-p model using cohesive elements in standard version. However, this approach has a drawback that it is hard to simulate complex debonding problems like element separation, rigid body motion, and contact between separated elements in standard version. ABAQUS-explicit can resolve these complex problems, but cohesive elements for the u-p model cannot be applied. We introduce a new algorithm for debonding for porous media instead of using cohesive elements. In this method, subroutines VUMAT to apply constitutive models and VDISP to separate elements in ABAQUS are used to simulate debonding problems. In addition, a simple 2-D example is demonstrated in the ABAQUS-explicit solver.

• Proceedings of the Korean Society of Postharvest Science and Technology of Agricultural Products Conference
• /
• 2003.10a
• /
• pp.194.2-195
• /
• 2003

본 연구는 수출방법의 개선과 절임 가공식품의 개발하고자 일본 수출용으로 재배하고 있는 축양종의 절임가지의 저장방법과 저장 중에 당류, 유기산 및 아미노산의 변화를 분석하였다. 총당 함량과 환원당 함량은 저장방법에 관계없이 저장기간이 길어질수록 조금씩 감소하였고, 침지 저장한 것보다는 진공포장하여 저장한 것이 변화가 적었다. 가지에서 분리 정량된 유기산은 acetic acid, citric acid, lactic acid, malic acid 그리고 succinic acid 총 5종이었으며 acetic acid와 malic acid의 함량이 가장 높았으며, 저장기간이 길어질수록 저장 초기에 비해 acetic acid의 함량은 증가하였는데 반해 malic acid의 함량은 감소하였다. 가지의 주요한 구성아미노산은 valine, aspartic acid, glutamic acid, glycine, alanine 등이었으며, 총아미노산 함량은 진공포장하여 저장한 경우에는 저장 20 일째 1488.14mg/100g으로 생가지보다도 증가하였는데 반해 침지하여 저장한 경우에는 총 아미노산 함량이 745.42mg/100g으로 서 저장 초기에 비해 감소함을 나타내었다. 유리아미노산은 aspartic acid, alanine, cystine과 proline 등의 함량이 높았고, 저장 기간이 길어질수록 저장초기에 비해 유리아미노산의 함량이 증가하였는데, 특히 진공 포장하여 저장한 가지에 비해 침지 저장 한 가지에서 그 함량이 높았다. 또한 아미노산 유도체의 함량은 phosphoserine, taurine, ${\gamma}$-aminoisobutyric acid 및 hydroxyproline의 함량이 높았고, 저장중에 phosphoserine의 함량은 감소하였는데 반해 ${\gamma}$-aminoisobutyric acid는 증가하였다. 축양품종의 절임가지의 저장방법과 저장기간에 따른 성분의 변화를 고려할 때 진공포장하는 것이 절임가지의 품질 유지할 수 있는 것으로 생각된다.

• Proceedings of the Korean Society of Postharvest Science and Technology of Agricultural Products Conference
• /
• 2003.10a
• /
• pp.195-195
• /
• 2003

본 연구는 수출방법의 개선과 절임 가공식품의 개발하고자 일본 수출용 시키부(Shikibu) 염절임 가지의 저장방법과 저장중에 당류, 유기산 및 아미노산의 변화를 분석하였다. 총당 및 환원당 함량은 저장방법에 관계없이 저장기간이 길어질수록 조금씩 감소하였고, 침지 저장한 것보다는 진공포장하여 저장한 것이 변화가 적었다. 가지에서 분리 정량된 유기산은 acetic acid, citric acid, lactic acid, malic acid 그리고 succinic acid 총 5종이었으며 acetic acid와 malic acid의 함량이 가장 높았으며, 저장기간이 길어질수록 저장 초기에 비해 acetic acid의 함량은 증가하였는데 반해 malic acid의 함량은 감소하였다. 가지의 주요한 구성아미노산은 valine, leucine, aspartic acid, glutamic acid, proline, alanine 등이었으며, 필수아미노산 함량은 저장기간이 길어질수록 저장 초기에 비해 진공포장하여 저장한 방법에서는 감소하였다가 증가하였는데 반해 침지하여 저장한 방법에서는 계속 증가하였고 저장 20일째에는 진공포장한 방법보다 l00mg/100g 정도의 차이를 나타내었다. 유리아미노산은 aspartic acid, alanine, cystine과 proline등의 함량이 높았고, 저장 기간이 길어질수록 저장초기에 비해 유리아미노산의 함량이 증가하였는데, 특히 진공 포장하여 저장한 가지에 비해 침지 저장 한 가지에서 그 함량이 높았다. 또한 아미노산 유도체의 함량은 phosphoserine, taurine, ${\gamma}$-aminoisobutyric acid 및 hydroxyproline의 함량이 높았고, 저장중에 phosphoserine의 함량은 감소하였는데 반해 ${\gamma}$-aminoisobutyric acid는 진공포장하여 20일 동안 저장하였더니 생가지 보다 5배 이상의 증가를 보였다. 스키부품종의 절임가지의 저장방법과 저장기간에 따른 성분의 변화를 고려할 때 축양품종과 동일하게 진공포장하는 것이 절임가지의 품질유지할 수 있는 것으로 생각된다.

• Journal of the Korea Society of Computer and Information
• /
• v.11 no.4 s.42
• /
• pp.283-289
• /
• 2006

The present image segmentation is what user want to segment image and has been studied for technology in composition of segment object with other images. In this paper, we propose a method of novel semi-automatic image segmentation using gradual region merging and genetic algorithm. Proposed algorithm is edge detection of object using genetic algorithm after selecting object which user want. We segment region of object which user want to based on detection edge using watershed algorithm. We separated background and object in indefinite region using gradual region merge from Segment object. And, we have applicable value which user want by making interface based on GUI for efficient perform of algorithm development. In the experiments, we analyzed various images for proving superiority of the proposed method.

• Journal of the Institute of Electronics Engineers of Korea SD
• /
• v.37 no.11
• /
• pp.43-49
• /
• 2000

In this paper, we have modeled and fabricated $1{\times}5$ equal power splitter for 1.55${\mu}m$ wavelength using finite-difference beam propagation method and $Ag^+-Na^+$ ion-exchanged method in BK7 glass, respectively. The power splitting ratio could be controlled by changing the center waveguide gap and the inner Y-branch angle. As a result, the power splitting ratio shows 0.46dB when the waveguide width, the inner Y-branch angle and the center waveguide gap are 4.5${\mu}m$, 0.3 degree and 575${\mu}m$, respectively.

• Journal of the Korea Organic Resources Recycling Association
• /
• v.23 no.4
• /
• pp.86-94
• /
• 2015

Torrefaction is a thermochemical process proceeded at the temperature around $250^{\circ}C$ in an inert gas condition. By torrefaction, the hemicellulose portions contained in biomass are broken down to change into the volatile gas which is removed from biomass eventually. The main purpose of biomass torrefaction is to improve the energy density of the biomass to minimize the transport energy consumption, though the flammability can be elevated for transportation. In this study two types of solid biomass fuel, waste wood and rice straw, were torrefied at various temperature range from $200^{\circ}C$ to $300^{\circ}C$ to evaluate the torrefied biomass characteristics. In addition torrefied biomass were tested to evaluate the combustion characteristics using TGA (Thermogravimetric Analysis). After the torrefaction of biomass, the C/H (carbon to hydrogen ratio) and C/O (carbon to oxygen ratio) were measured for aquisition of bio-stability as well as combustion pattern. Generally C/H ratio implies the soot formation during combustion, and the C/O ratio for bio-stability. By torrefaction temperature at $300^{\circ}C$, C/H ratio and C/O ratio were increased by two times for C/H and three times for C/O. The torrefied biomass showed similar TGA pattern to coal compared to pure biomass; that is, less mass decrease at lower temperature range for torrefied biomass than the pure biomass.

• KSBB Journal
• /
• v.18 no.6
• /
• pp.461-465
• /
• 2003

Five denitrifying bacteria, which were identified as Pseudomonas sp., were isolated by the enrichment culture technique. The most effective denitrifying bacterium was named as Pseudomonas DWS, which was cultivated at anoxic condition. The optimal growth temperature and pH were 30$^{\circ}C$ and 7-8, respectively. Cell growth almost revealed a stationary phase at 18 hours after cultivation and nitrate was degrade 99.9％ during this period. Therefore, it is suggested that Pseudomonas DWS could be effectively used for the biological treatment of wastewater containing nitrogen compounds.