• Fire Science and Engineering
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• v.24 no.1
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• pp.122-127
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• 2010

The combustion characteristics of phenol foam were analysed using variable external irradiation level (20, 25, 35, 50, and $70kW/m^2$) and in the mixture gas of oxygen/nitrogen. The oxygen index were carried out from the oxygen index tester (KS M ISO 4589-2) and ignition time, critical heat flux, and mass loss rate were carried out from the mass loss calorimeter (ISO 5660-1). As the results of this study, the critical heat flux and average mass loss rate were $28.99kW/m^2$ and $0.56{\sim}1.77g/m^2s$ respectively at the variable external irradiation level. And the limited oxygen index were 45.1% in mixture gas of oxygen/nitrogen. In conclusion, we knew that phenol foam had the best performance than other foam materials in fire safety from all data of this study.

• Journal of the Korea Computer Industry Society
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• v.3 no.3
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• pp.369-382
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• 2002

The increase of vehicles stagnations leads to the increasing attention to the way customers pay and a large number of Projects on electronic cash system. Tranport system is comprised of a number of advanced technologies, including information processing, communications, control, and electronics. Recently many research on a system which provides contact in order to protect driver's vehicle passage have been carried out. And some potential problems from that system are being reviewed by electronic cash system. In this papers, we suggest RF protocol developing technology using the concept of electronic cash. ATM electronic cash developing is consist of component of pre-developed coin throw, integration of component using its, and production of more requirement-satisfactory ITS solution. Result increase 15-40% pre-type vehicles stagnations. Especially, we expect this proposed concept would be well adapted to our national environments.

• Korean Journal of Plant Resources
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• v.22 no.2
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• pp.111-115
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• 2009

The seeds of Phellodendron amurense have difficulty to obtain because these plants show dioecism with independent distributions. This experiment was conducted to find the effects of soaking and prechilling treatment on the germination of P. amurense seeds. Seeds were soaked for 3, 5 and 10 days (soaking treatment), and placed on petri-dish at $4^{\circ}C$ for 10, 20, 30 and 50 days after soaked at room temperature for 24 hours (prechilling treatment). After the treatments, germination percentage, mean germination time, germination speed and germination performance index were analyzed. As a result of sowing, prechilled seeds for 30 days had the highest percent of germination, whereas all of the soaked seeds showed lower percent of germination than non-treatment (control). In case of mean germination time, only prechilling for 30 days was more effective than control. In germination speed, all of the soaked seeds had lower values than control whereas all prechilled seeds except prechilled seeds for 20 days showed higher values than control. Especially prechilled seeds for 30 days showed the highest rate among the prechilling treatments. Germination performance index was similar to germination speed.

• Journal of the Korean GEO-environmental Society
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• v.12 no.5
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• pp.29-36
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• 2011

In this study, settling experiment was performed about cohesive and sandy soils among representative sample expected to dredge and dump for analysis of settling and consolidation characteristic. The analysis showed the definite difference between cohesive soils and sandy soils of relationships with settling and consolidation coefficient, a water content, interfacial heights. But directly after a dredged reclamation, prediction results about a initial volume change showed that cohesive soil of a water content change was decreased rapidly as time goes by, but sandy soils made no difference in a water content change. Results were compared and analyzed with the settling and consolidation coefficient and a initial settling velocity by real soil amounts for a feasibility check about test conditions applied to these experiment: we judge that test conditions are appropriate, each material by such these analyses suggests the scope of settling and consolidation coefficient, average and the representative relational formula.

• The Journal of the Korea institute of electronic communication sciences
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• v.17 no.4
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• pp.577-586
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• 2022

Detection and classification of steel surface defects are critical for product quality control in the steel industry. However, due to its low accuracy and slow speed, the traditional approach cannot be effectively used in a production line. The current, widely used algorithm (based on deep learning) has an accuracy problem, and there are still rooms for development. This paper proposes a method of steel surface defect detection combining EfficientNetV2 for image classification and YOLOv5 as an object detector. Shorter training time and high accuracy are advantages of this model. Firstly, the image input into EfficientNetV2 model classifies defect classes and predicts probability of having defects. If the probability of having a defect is less than 0.25, the algorithm directly recognizes that the sample has no defects. Otherwise, the samples are further input into YOLOv5 to accomplish the defect detection process on the metal surface. Experiments show that proposed model has good performance on the NEU dataset with an accuracy of 98.3%. Simultaneously, the average training speed is shorter than other models.

• Microbiology and Biotechnology Letters
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• v.26 no.6
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• pp.545-550
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• 1998

Succinic acid, valuable $C_4$-dicarboxylic acid as a renewable alternative feedstock, is currently produced commercially by the petrochemical process, but extensive efforts have been devoted to establish the biological process for mass production of succinic acid. In this study, the bioconversion of fumaric acid to succinic acid was investigated. We isolated an Enterococcus sp. RKY1 KCTC 8890P, facultative bacterium, capable of the bioconversion of fumaric acid to soccinic acid very rapidly and efficiently. At batch fermentation, the amount of succinic acid production increased with increase in initial fumaric acid from 40 to 100 g/L. With fumaric acid of 70 g/L, the average specific and volumetric production rate, molar yield were reached up to 0.64 g/g.h, 4.87 g/g.h, and 96.5%, respectively. Maximum concentration of succinic acid of 88.9 g/L was achieved with molar yield of 89% with fumaric acid of 100 g/L in less than 20 hours.

• Korean Journal of Remote Sensing
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• v.30 no.2
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• pp.161-172
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• 2014

Established in the lower reaches of the Nakdong river in Busan, the Noksan national industrial complex is one of the deepest soft ground areas in Korea. In case of the costal landfill having deep soft ground, there is a significant residual settlement over a long period of time. In this study, there was observed ground subsidence occurred in the Noksan national industrial complex from September 2002 to April 2007 by applying DInSAR and SBAS time series method using RADARSAT-1 and Envisat SAR datasets. As a result, it was calculated that ground subsidence developed at the velocity of about maximum 10 cm/yr and mean 6 cm/yr at the eastern center, west, western center and southern area contiguous on the coastline of the study area during the period from September 2002 to April 2007. In addition, the RADARSAT-1 average displacement map has been compared with the total displacement map observed by accurate magnetic probe extensometer during the period from 2001 to 2002. Since the time series displacement has shown a linear trend mostly, we consider that continuous monitoring should be needed until the ground subsidence of the study area has been stabilized.

• Journal of Energy Engineering
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• v.7 no.1
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• pp.57-64
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• 1998

A neutralized fabric filter of which major raw materials were polyester and stainless steel fibers was developed and its physiochemical properties and basic filter characteristics were investigated. Four finds of dusts generated in the typical domestic industry were used, which were coke dust from a steel manufacturing process, cement dust from a cement manufacturing process, flu ash from a fluidized-bed combustor, and incinerator ash from a waste plastics incinerator. The physicochemical properties of the neutralized fabric filter were analyzed in terms of changes in tensile strength and initial elastic modulus under $SO_2$ and $NO_2$ atmospheres, mean flow pore pressure, bubble point pore diameter, mean flow pore diameter, and pore size distribution. In addition, the pressure drop, dust penetration, and figure of merit for the fabric filter were investigated in a bench-scale filter testing unit. The pressure drop increased as the filtration velocity and dust loading increased, and its increasing shape depended on the type of dust. The dust penetration rapidly decreased as the dust loading increased irrespective of the type of dust. The figures of merit for the fabric filters increased in the early stage of filtration and then showed rapid decreases followed maintaining a constant level.

• Proceedings of the Korean Vacuum Society Conference
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• 2013.02a
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• pp.351-351
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• 2013

한국 전체 에너지 사용량 중약 24%의 에너지가 건축물 부분에 소비되고 있다. 건축물의 벽체나 유리창 등을 통해서 에너지 손실이 이루어지는데 유리창은 벽체에 비해 약 10배 이상 낮은 단열 특성을 가지고 있기 때문에 유리창을 통한 열손실량은 더 크다. 이러한 유리창 부분의 열손실 문제를 해결할 수 있는 방안으로 좋은 단열 특성 및 낮은 방사율을 가지고 있는 Low-e coating 방법을 사용하였다. 본 실험에서는 XG glass 기판 위에 IGZO/Ag/IGZO OMO 구조의 다층 박막을 증착하였다. RF magnetron sputtering방법을 이용하여 OMO 구조의 상부와 하부의 Oxide layer로 IGZO 박막을 증착하였다. 사용된 IGZO 타겟은 $In_2O_3$ (99.99%), $Ga_2O_3$ (99.99%), ZnO (99.99%)의 분말을 각각 1:1:1 mol% 조성비로 혼합하여 소결하여 제작하였다. Thermal Evaporator 장비를 이용하여 OMO 구조의 Metal layer로 Ag (99.999%)를 증착하였다. 실험 기판은 크기 $30{\times}30mm$의 0.7T XG glass를 사용하였다. OMO 구조의 산화층 IGZO 박막은 상/하층 동일 조건으로 기판 온도는 실온으로 고정하였으며, 초기 압력 $3.0{\times}10^{-6}$ Torr, 증착 압력 $3.0{\times}10^{-2}$ Torr, RF 파워 50W, Ar 유량 50 sccm로 고정시키고 증착 시간이 변화하면서 박막을 증착하였다. OMO 구조의 Metal layer로 Ag 증착 조건은 초기 진공도가 약 $6.0{\times}10^{-6}$ Torr 이하로 유지하고 기판을 2 Rpm의 속도로 회전시켰다. 이후 0.3 V로 Ag를 10분간 가열하여 충분히 녹인 후 Film Thickness Monitor로 두께를 확인하였다. OMO 다층 박막의 산화물층 변화에 따라 로이다층 박막의 구조적, 광학적 및 전기적 특성을 분석하였다. XRD 분석결과에 의하여 Bragg's 법칙을 만족하는 피크가 나타나지 않는 비정질 구조임을 확인할 수 있으며, AFM 분석결과에 통해서 최소 1.3 nm의 Roughness를 나타내었다. UV-Visible-NIR 분광광도계를 이용하여 다층 박막은 가시광선 영역에서 평균 80%의 광 투과성을 보여 IR 영역에서 평균 30% 투과하고 좋은 차단 특성을 나왔다. Low-e 특성을 갖는 유리창을 통해서 에너지 절약을 이룰 수 있는 것을 확인할 수 있었다.

• Journal of the Institute of Convergence Signal Processing
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• v.9 no.1
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• pp.10-17
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• 2008

The purpose of this thesis is to reduce of error for source location through acoustic emission(AE) signal, generated elastic wave from crack growth to leak for facility diagnosis. Especially, in order to overcome noise from original signal, this paper proposed enhancement of source location by using noise reduction based on wavelet transform. To evaluate actual performance in experiments, Pencil Lead Break is used crack signal source on the aluminum plate and drain valve of air compressor is used as substitute pressure vessel to generate leak signal. In signal processing, wavelet shrinkage and soft threshold are used to discriminate signal source and then source location techniques have been effectively used with group velocity using material property and time difference between sensor using cross correlation. Source location for crack and leak test have some difference, but the result show that improved 30% with a average length within 10.46mm in crack test and improved 2% compare with average filter in leak test when we applied wavelet transform.