• Nuclear Engineering and Technology
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• 제52권4호
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• pp.755-763
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• 2020

The critical flow phenomenon has been studied because of its significant effect for design basis accidents in nuclear power plants. Transition points from thermal non-equilibrium to equilibrium are different according to the geometric effect on the critical flow. This study evaluates the uncertainty parameters of the critical flow model for analysis of DBA (Design Basis Accident) with the MARS-KS (Multi-dimensional Analysis for Reactor Safety-KINS Standard) code used as an independent regulatory assessment. The uncertainty of the critical flow model is represented by three parameters including the thermal non-equilibrium factor, discharge coefficient, and length to diameter (L/D) ratio, and their ranges are determined using large-scale Marviken test data. The uncertainty range of the thermal non-equilibrium factor is updated by the MCDA (Model Calibration through Data Assimilation) method. The updated uncertainty range is confirmed using an LBLOCA (Large Break Loss of Coolant Accident) experiment in the LOFT (Loss of Fluid Test) facility. The uncertainty ranges are also used to calculate an LBLOCA of the APR (Advanced Power Reactor) 1400 NPP (Nuclear Power Plants), focusing on the effect of the PCT (Peak Cladding Temperature). The results reveal that break flow is strongly dependent on the degree of the thermal non-equilibrium state in a ruptured pipe with a small L/D ratio. Moreover, this study provides the method to handle the thermal non-equilibrium factor, discharge coefficient, and length to diameter (L/D) ratio in the system code.

• Journal of the Korean Wood Science and Technology
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• 제43권5호
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• pp.682-690
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• 2015

The bonding performance of two types of wood adhesives, namely phenol-resorcinol-formaldehyde (PRF) resin and melamine-urea-formaldehyde (MUF) resin for glued laminated timber manufactured by high frequency (HF) heating was evaluated. The HF heating system consists of HF oscillator with dielectric heating system for curing adhesives, and hydraulic press system for clamping glued laminated timber. The designed frequency and output power of the HF system was as 5 MHz and 60 kW, respectively. To verify dielectric heating mechanism under HF oscillation, the heat loss factors of laminae and adhesives were measured. The results show that it is possible to selectively heat adhesives for their curing due to the remarkably higher loss factor of the adhesives than those of wood laminae. The temperature of adhesive in the bonding line reached up to the set temperature within a few seconds by high frequency oscillating, which advanced the curing of adhesive afterwards. The bonding performance, such as shear strength of bonding line, water soaking delamination, and boiling water soaking delamination of PRF resin met the requirement of Korean Standard (KS), however the MUF resin did not meet the KS requirement of boiling water soaking delamination. These results indicate that the HF heating system is successful to manufacture glued laminated timbers with PRF resins to meet the bonding requirements.

• Applied Biological Chemistry
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• 제35권4호
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• pp.281-285
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• 1992

시판 쇠고기 맛 복합조미료를 PE/Al/PE/PET의 적층포장재로 포장저장중 온도인자에 의한 $Q_{10}$값은 2.54였으며 이로부터 $35^{\circ}C$, $25^{\circ}C$ 및 $15^{\circ}C$에서의 shelf-life는 각각 29주, 73주 및 185주로 예측되었다. 색상중 L값은 $50^{\circ}C$ 저장중 다소 감소하였으나 a 및 b값은 큰 변화가 없었으며 색상과 기호도와의 상관계수는 대체로 낮게 나타났다. 갈변도와 카르보닐값은 저장중온도가 높을수록 증가하는 경향이었으며 기호도와의 상관계수는 비교적 높게 나타났다. 수분, 염도 및 총당은 저장 전기간중 KS-규격기준에 적합하였다.

• 한국건축시공학회지
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• 제23권1호
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• pp.45-56
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• 2023

본 연구는 PC공법에 적용되는 실링재를 대상으로 수밀성 측면의 내구성 평가방안 마련의 타당성을 검토하기 위하여 진행하였다. 이를 위해 관련 KS표준의 품질기준에 동일하게 만족하는 실링재 5종을 선정하여 시험을 진행하였으며, 시험결과 5종의 실링재 중 3개 실링재가 바탕면과의 탈락 및 균열 등 수밀성 저하를 나타냈으며, 2종의 경우 육안관찰 상 큰 변화는 없었으나, 추가분석을 통해 소재의 응력 저하율의 차이가 크게 발생하는 것을 확인할 수 있었다. 이에 상기 결과를 근거로 향후 실링재 간 수밀성 측면의 성능검토 필요성을 확인하였으며, 이를 기반하여 제품 선정 시 활용 가능한 수밀성 평가방안의 타당성을 정량적으로 확인하였다.

• 대한토목학회논문집
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• 제35권6호
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• pp.1431-1438
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• 2015

최근 경제협력개발기구(OECD)보고서에 따르면 세계 교역량의 80%가 표준의 영향을 받고 있으며, 유럽연합(EU) 무역의 50%는 강제규격 인증을 요구하고 있다. 이로인해 각 기업과 국가들은 산업별 신기술에 대한 연구개발(R&D)과 연계하여 자신들의 신기술에 대한 표준창출과 이를 국제 표준화하는데 사활을 건 경쟁을 벌이고 있다. 즉, 기술표준은 생산비용 절감에서 시장지배 수단으로서 전 산업분야에 걸쳐 표준을 주도하는 집단이 시장을 지배하는 경쟁시대 관점에서 보다 적극적인 개념으로 이해할 필요성이 있다. 건설표준화는 건설R&D 성과 확산에 있어 중요한 역할을 수행하는 분야로 예측되며, 건설공사기준, KS표준 등에 반영되어 향후 글로벌 시장에서 경쟁력 강화를 위해 필수적인 전략이 된다. 그럼에도 국내 건설산업은 제조업에 비해 표준화 관련연구 및 정책적 관점의 분석이 상대적으로 미흡하였다. 이에 본 연구에서는 건설R&D사업과 표준화의 연계 관점에서 성과에 따른 효과를 분석하기 위한 기준을 정립하고자 한다. 또한, 이를 기반으로 기 종료된 건설R&D과제 성과로부터 도출된 표준 산출물(Output)의 특성과 그에 따른 파급효과 분석을 통해 국내 건설기술표준화의 가치를 제고할 수 있는 기반을 제시하고자 한다.

• 한국ITS학회 논문지
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• 제8권5호
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• pp.71-84
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• 2009

교통신호제어기의 표준규격에서 센터시스템과 지역제어기 간 통신방식은 전용선을 기준으로 한 모뎀방식의 시리얼통신으로 규정되어 있어, 지방도시에서 구축 운영되는 TCP/IP의 ITS 통신망에 내에 교통신호제어시스템에 대한 통신규격을 수용하지 못하고 있는 실정이다. 또, ITS 부문에서 데이터 교환을 위한 국내외 표준으로 이더넷 통신망을 기반으로 한DATEX-ASN 데이터 교환기술이 채택되고 있다. 따라서 본 연구는 교통신호제어시스템이 ITS 통신망 내에 구성이 가능하도록, TCP/IP 프로토콜을 기반으로 한 교통신호제어기 통신규격(안)을 개발을 목적으로 한다. 제어, 상태정보와 데이터 베이스 정보 등 표준규격 교통신호제어기의 23개 통신항목에 대한 통신규격(안)이 DATEX-ASN 통신처리 절차 및 구조 (KS ISO X 14827 Part1, 2, ISO/ DIS 15784 Part-3)를 적용하여 개발하였다. 실험을 위하여 통신항복별로 응용프로그램을 개발하였으며, 실험결과 통신항목 모두 인코딩 및 디코딩처리가 가능하였다.

• Journal of the Korean Wood Science and Technology
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• 제44권4호
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• pp.607-615
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• 2016

The delamination along the annual ring on the cross-section of laminae and the bonding strength according to the tangential angle between laminae were evaluated for the production of 3-ply cross-laminated timber (CLT) using domestic larch. Since there is no standard for CLT in Korea, the production and test of specimens for bonding strength followed the standard procedure of "Structural glued laminated timber" (KS F 3021). The standard specifies to exclude any measurement from the cracks of timbers resulted from drying or knots during delamination test of the glued laminated timbers. However, the failure of cross-sectional tissues along the annual rings was observed near the glue-line of all specimens during the delamination test. Because this phenomenon can generate defects in the CLT that may be exposed to various temperatures and relative humidities after the actual construction, the delamination percentage was measured by including this wood failure. As a result, the delamination percentage of the CLT which had been combined in such a way that the annual rings of outer lamina were directed inward was the lowest, which was around 13%, regardless of the annual ring direction of the middle lamina. On the other hand, the delamination percentage of the CLT which had been combined in such a way that the annual rings of outer lamina were directed outward was the highest, which was around 26%. Furthermore, end-split occurred in the outer lamina during the drying process of the boiling delamination test, which affected the delamination percentage. Therefore, the soaking delamination test was found to be more appropriate for evaluating the delamination strength of CLT. The block shear strength of larch CLT was $3.9{\pm}0.9$ MPa on average, which was 46% lower than the block shear strength requirement (7.1 MPa) of the standard, but satisfied the criteria of the block shear strength (3.5 MPa) of the European Standard (prEN 16351: 2013).

• 수산해양교육연구
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• 제26권4호
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• pp.823-830
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• 2014

This study conducted to investigate the quality of commercial fish sauce and determine the grade of them by measuring the chemical compositions and biogenic amines. The commercial salt-fermented anchovy sauce contained 65.84-70.94% (mean : 68.39%) of moisture, 22.19-25.43% (24.22%) of salinity, 5.4-6.1 (5.8) of pH, 0.76-1.61%(1.18%) of total nitrogen, 478.52-924.66 mg/100 g (702.05 mg/100 g) of amino nitrogen and 584.59-1593.52 mg/kg of histamine. Whereas commercial salted-fermented sand lance sauces contained 66.63-71.99% (68.73%) of moisture, 23.9-25.5% (24.57%) of salinity, 5.5-6.4(6.16) of pH, 0.64-1.46% (1.07%) of total nitrogen, 433.51-1006.67 mg/100 g (665.36 mg/100 g) of amino nitrogen and 194.01-1839.68 mg/kg of histamine. Correlation of TN, AN and VBN containing nitrogen was high, but there was no significant correlation between these results and histamine. In total nitrogen content, 6 of the 20 fish sauces were less than Korea Food Standard. The eight samples were less than the amino nitrogen regulation of Korean Industrial Standard (KS). And 14 fish sauce were exceeded by 68% for moisture content standard of Korean Industrial Standard.

• 한국콘크리트학회:학술대회논문집
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• 한국콘크리트학회 2004년도 춘계 학술발표회 제16권1호
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• pp.28-31
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• 2004

This paper discusses the role of micro and macrofibers in the workability, compressive strength, and failure of cementitious composites. Workability(flow), compressive strength, splitting strength and fracture mechanism of hybrid fiber reinforced cement composites(HFRCC) have been investigated by means of Korean Standard (KS). The specific blend pursued in this investigation is a combination of polyvinyl alcohol(PVA) and steel cord. It was demonstrated that a hybrid combination of steel and PVA enhances fiber dispersion compared to only steel cord reinforced cement composites and that the brittle and wide cracking was much reduced in HFRCC as expected because in the matrix containing the PVA fiber around the steel cord, a multiple microcracking occurred and the steel cord could sufficiently work for bridging the cracked surface.

• 한국콘크리트학회:학술대회논문집
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• 한국콘크리트학회 2006년도 춘계 학술발표회 논문집(II)
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• pp.141-144
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• 2006

In this study, evaluation of physical and chemical properties of crushed sand was performed to establish optimal mix proportion standard for concrete using crushed sand afterward. Most of properties of crushed sand were satisfied with KS F 2527. Especially, chemical stabilities such as alkali-aggregate reaction were fairly good. However, considerable attention would be required in using crushed sand from lime stone judging from the result that weight loss of it was more than 23.8%. There were some differences in the properties with production region, stone type and capacity of facility, therefore it is thought that quality should be controled by optimal regulations for corresponding items.