• 대한가정학회지
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• 제19권2호
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• pp.165-174
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• 1981

The survey was conducted through circulating questionares to three hundred sampled college students in Seoul. the findings are as follows. 1. 52% of MS (Male Students) and 25% of FS(Female Students) brought home-made lunches with them, while 39.2% of MS and 51.6% of FS used food services in campus. 2. Contents of home-made lunches were steamed rice(57%) or steamed ricebarley mix(24%) as a major diet, and Kimchi (Korean style pickled vegetable), fried eggs, soy-sauced sardins as side-dish. The favorite eating places for the students with home-made lunches were found to be campus dining hall for MS, classrooms for FS. 3. The primary reason for not having home-made lunches are the difficulties for handing. 4. The preference for the food served in campus dining hall was the traditional Korean food for MS and western style Snack (bakery and soft drinks) for the FS. 5. Costs spent for lunches were in the range of 200~600 won. 6. Followings are the comparison table for each ingredient compared with recommended daily requirement (RDR).

• 대한원격탐사학회지
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• 제19권3호
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• pp.201-208
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• 2003

Much effort has been made in the radiometric calibration of the ocean scanning multispectral imager (OSMI) since after the successful launch of KOMPSAT-1 in 1999. A series of calibration coefficients for OSMI detectors were obtained in collaboration with the NASA Sensor Intercomparison and Merger for Biological and Interdisciplinary (SIMBIOS) project office. In this study, we ompare the OSMI level-2 products (e.g., chorophyll-a concentration) calculated from the NASA cross-calibration coefficients with the SeaWiFS counterparts. Sample study areas are some of diagonostic data sites recommended by the SIMBIOS working group. Results of this study show that the OSMl-derived chlorophyll-a concentration agrees well with the SeaWiFS counterpart in Case 1 water; however, differences become larger in Case 2 water.

• 전자공학회논문지B
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• 제31B권7호
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• pp.129-140
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• 1994

In this paper we investigate the hardware implementation of block matching algorithms (BMAs) for moving sequences. Using systolic arrays we propose a hardware architecture of a two-stage BMA using integral projections which reduces greatly computational complexity with its performance comparable to that of the full search (FS). Proposed hardware architecture is faster than hardware architecture of the FS by 2~15 times. For realization of the FS and two stage BMA modeling and simulation results using SPW and VHDL are also shown.

• 한국소성가공학회:학술대회논문집
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• 한국소성가공학회 1997년도 춘계학술대회논문집
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• pp.77-80
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• 1997

The torsion tests in the range of 900~110$0^{\circ}C$, 5.0$\times$10-2~5.0$\times$100/sec were performed to study the recry stallization behavior of 304 stainless steel in the high temperature multistage deformation. The no-recrystallization temperature(Tnr) and fractional softening(FS) were determined by the change of flow curves. The inflection points of stress slope were moved to lower temperature area as the strain rate and the interrupt time were increased. From the multipass flow curve, the intersection between pass stress and FS curve was corresponding to the pass which the FS dropped abruptly and it was shown that the recrystallization area could be determined by the FS measurement in multipass deformation.

• 한국토양비료학회지
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• 제45권4호
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• pp.515-523
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• 2012

본 연구는 메탄생성에 직접적으로 관여하는 혼합 메탄균과 셀롤로스 등의 고분자 물질의 가수분해 반응에 활성이 뛰어난 반추위 내 혐기성 섬유소분해균 중에서 대표적인 Fibrobacter succinogenes, Ruminococcus flavefaciens 및 Ruminococcus albus를 biochemical methane potential (BMP) 시험에 첨가하였을 때 메탄 발생에 미치는 영향을 조사하고자 수행되었다. BMP시험은 멸균증류수를 첨가한 control과 각각의 미생물 배양액을 첨가한 혼합 메탄균 첨가구 (M), F. succinogenes 첨가구 (FS) R. flavefaciens 첨가구 (RF), R. albus 첨가구 (RA) 및 RA+FS 혼합첨가구와 M+RA+FS 혼합 첨가구로 총 7개 처리구로 각 처리구별 3반복으로 진행되었다. 미생물 배양액의 첨가량은 식종액과 기초혐기배지 (anaerobic basic medium) 혼합액 50 mL에 1% (0.5 mL), 3% (1.5 mL) 및 5% (2.5 mL) 씩 첨가 하였고 배양을 위한 기질로는 cellulose ($2.0g\;VS\;L^{-1}$)이 이용되었다. BMP 시험을 위해 40일간 배양이 지속되었고 중온소화를 위해 $38^{\circ}C$의 배양기에서 수행되었다. 실험의 결과 총 바이오가스 및 메탄 발생량은 5% FS에서 다른 처리구와 비교하여 각각 10.4~22.7% 및 17.4~27.5% 높았다 (p<0.05). 총고형물 (TS) 분해율도 가스발생 결과와 유사하였는데, 전반적으로 FS가 높게 나타났으며, 5% FS에서 64.2%로 가장 높았다. 휘발성 고형물 (VS) 분해율은 5% FS와 5% RF가 각각 68.4 및 71.0%로 가장 높았다. BMP 종료시 배양액내 pH는 모든 처리구가 6.4이상으로 메탄발효에 큰 영향을 주지 않았음을 알 수 있었다. 결론적으로 본 실험의 결과 혐기소화에 대한 회분식 배양에서는 메탄생성단계보다는 가수분해단계에서 특히, F. succinogenes 배양액의 첨가량이 증가할수록 메탄의 생성량을 증가시킴을 알 수 있었다.

• Geomechanics and Engineering
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• 제21권6호
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• pp.513-525
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• 2020

Slopes stabilised with piles are seldom analysed considering uncertainties in the parameters of the pile-slope system. Reliability analysis of the pile-slope system quantifies the degree of uncertainties and evaluates the safety of the system. In the present study, the reliability analysis of a slope stabilised with piles is performed using the first-order reliability method (FORM) based on Hasofer-Lind approach. The implicit performance function associated with the factor of safety (FS) of the slope is approximated using the response surface method. The analyses are carried out considering the design matrices formulated based on both the 2^k factorial design augmented with a centre run (2^k fact-centred design) and face-centered cube design (FCD). The finite element method is used as the deterministic model to compute the FS of the pile-slope system. Results are compared with the results of the Monte Carlo simulation. It is observed that the optimum location of the row of piles is at the middle of the slope to achieve the maximum FS. The results show that the reliability of the system is not uniform for different pile configurations, even if the system deterministically satisfies the target factor of safety (FS_t) criterion. The FS_t should be selected judiciously as it is observed that the reliability of the system changes drastically with the FS_t level. The results of the 2^k fact-centred design and FCD are in good agreement with each other. The procedure of the FCD is computationally costly and hence the use of 2^k fact-centred design is recommended, provided the response of the system is sufficiently linear over the factorial space.

• 한국세라믹학회지
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• 제31권8호
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• pp.861-868
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• 1994

CaO-Al2O3 glass is a good candidate as optical fiber amplifier and laser. In this study, optical properties for 4I13/2longrightarrow4I15/2 transition of Er3+ ions doped in CaO-Al2O3 glasses were investigated. Optical absorptions, radiative transition probabilities and lifetimes for 4I13/2 level were evaluated by using Judd-Ofelt theory. Also, induced- emmision cross-sections of 4I13/2longrightarrow4I15/2 transition were calculated. Radiative transition probability and lifetime of 4I13/2 level were 144.6s-1, 690$mutextrm{s}$ respectively for 60CaO.40Al2O3 glass(FS0) and 152.6s-1, 660 $mutextrm{s}$ for 54 CaO.36Al2O3.10SiO2 glass (FS10). Each induced-emission cross sections for FS0 and FS10 was 0.749$\times$10-20 $\textrm{cm}^2$, 0.892$\times$10-20 $\textrm{cm}^2$. Obtained values were comparable with those of ZBLA glass studied as optical fiber amplifier and laser material.

• Restorative Dentistry and Endodontics
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• 제39권3호
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• pp.180-186
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• 2014

Objectives: The purpose of this in vitro study was to evaluate the microleakage and penetration of fissure sealant in permanent molar teeth with fluorosis after pretreatment of the occlusal surface. Materials and Methods: A total of 120 third molars with mild dental fluorosis were randomly divided into 6 groups (n = 20). The tooth surfaces were sealed with an unfilled resin fissure sealant (FS) material. The experimental groups included: 1) phosphoric acid etching (AE) + FS (control); 2) AE + One-Step Plus (OS, Bisco) + FS; 3) bur + AE + FS; 4) bur + AE + OS + FS; 5) Er:YAG laser + AE + FS; and 6) Er:YAG laser + AE + OS + FS. After thermocycling, the teeth were immersed in 0.5% fuchsin and sectioned. Proportions of mircoleakage (PM) and unfilled area (PUA) were measured by digital microscope. Results: Overall, there were significant differences among all groups in the PM (p = 0.00). Group 3 showed the greatest PM, and was significantly different from groups 2 to 6 (p < 0.05). Group 6 showed the lowest PM. Pretreatment with Er:YAG with or without adhesive led to less PM than bur pretreatment. There were no significant differences among groups in PUA. Conclusions: Conventional acid etching provided a similar degree of occlusal seal in teeth with fluorosis compared to those pretreated with a bur or Er:YAG laser. Pretreatment of pits and fissures with Er:YAG in teeth with fluorosis may be an alternative method before fissure sealant application.

• Steel and Composite Structures
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• 제42권2호
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• pp.277-288
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• 2022

A novel flat steel plate-concrete-corrugated steel plate (FS-C-CS) sandwich panel was proposed for resisting impact load. The failure mode, impact force and displacement response of the FS-C-CS panel under impact loading were studied via drop-weight impact tests. The combined global flexure and local indentation deformation mode of the FS-C-CS panel was observed, and three stages of impact process were identified. Moreover, the effects of corrugated plate height and steel plate thickness on the impact responses of the FS-C-CS panels were quantitatively analysed, and the impact resistant performance of the FS-C-CS panel was found to be generally improved on increasing corrugated plate height and thickness in terms of smaller deformation as well as larger impact force and post-peak mean force. The Finite Element (FE) model of the FS-C-CS panel under impact loading was established to predict its dynamic response and further reveal its failure mode and impact energy dissipation mechanism. The numerical results indicated that the concrete core and corrugated steel plate dissipated the majority of impact energy. In addition, employing end plates and high strength bolts as shear connectors could prevent the slip between steel plates and concrete core and assure the full composite action of the FS-C-CS panel.

• 분석과학
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• 제19권3호
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• pp.263-271
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• 2006

변압기 절연유 중 PCBs, Co-PCBs 및 PCDD/Fs를 GC/ECD와 HRGC/HRMS를 이용하여 정량한 결과 각각 N.D.~77.3 ppm, 0.0863~2.49 ppm과 N.D.~0.00241 ppm으로 검출되었다. WHO-TEQ 농도는 Co-PCBs가 23.3~600 pgTEQ/g, PCDD/Fs가 N.D.~128 pgTEQ/g (${\Sigma}Co$-PCBs+PCDD/Fs은 24.4~728 pgTEQ/g)으로 검출되어, 총 TEQ 농도 중 PCDD/Fs가 차지하는 비율은 12% 이하였으나, 변압기 절연유 중에 미량의 다이옥신이 존재하는 것으로 나타났다. 총 10개의 시료 중 4개의 시료에서 현행 기준인 2 ppm을 초과하였으며, 시료에 따라서 Aroclor 1242, 1248, 1254 및 1260이 단품 혹은 혼합품의 형태로 포함되어 있었다. 또한 Co-PCBs와 PCDD/Fs의 농도사이에 상관성이 나타났으나 (P<0.003), 변압기의 제작년도와 농도사이에 상관성은 나타나지 않았다. Co-PCBs 이성체 분포에 있어서 non-ortho 치환 이성체에 비해 mono-ortho 이성체가 높은 비율을 차지하였으며, PCB-118 이성체가 모든 시료에서 42% 이상으로 가장 높은 비율을 차지하였다. PCDD/Fs 이성체 분포에 있어서는 OCDD가 53% 이상으로 다른 이성체에 비해 높은 비율을 차지했다. 또한 일부 시료 중 Co-PCBs의 이성체패턴은 환경 대기시료 뿐만 아니라 PCBs 제품인 Aroclor와 유사한 패턴을 나타내어, 변압기 절연유가 대기 중 PCBs의 오염원 중 하나라는 것이 시사되었다.