2016년 경주지진(규모 5.8) 및 2017년 포항지진(규모 5.4)은 1978년 대한민국 지진 관측 이래 국내 에서 발생한 지진 중 가장 큰 피해가 발생한 지진으로 기록되었다. 지진의 피해사례는 다양한 분야에 서 발생되었으며, 그중 교량 구조물에도 부분적인 피해가 다수 발생하였다. 국내에서는 교량구조물에 대한 내진보강 사업을 지속적으로 진행하고 있으며, 내진 보강의 공법 중 면진받침을 적용하여 구조물 의 내진성능을 확보하는 사례는 지속적으로 증가하고 있는 추세이다. 펜들럼 교량받침은 중간판의 기 하학적인 곡률과 고강도 마찰재를 이용하여 감쇠 기능뿐 아니라 복원 기능을 구비하고 있는 면진받침 으로써 제품 크기가 작아 시공성, 경제성이 우수하여 국내에서 가장 많이 사용되고 있는 대표적인 면 진장치이다. 펜들럼 받침의 경우 지진력 감쇠 및 회전, 이동량 수용을 위하여 2면의 곡면 구조로 진자 운동을 하므로 수평 변위 발생 시 필수적으로 수직 단차가 발생하는 구조이다. 또한 면압에 따라 마찰 계수가 달라지는 마찰재의 특성을 고려한 특성치 산출이 필요한 제품이다. 이 연구에서는 펜들럼 받침 의 다양한 면압에 따른 동적 시험을 실시하여 실제 거동과 일치하는 설계 특성치 산출법을 정립하였 다. 또한 펜들럼 면진받침의 진자 운동을 반영한 모양의 가이드와 프리세팅 전, 후에도 받침 상판의 수평을 유지할 수 있는 장치를 실물 크기로 제작하여 공인기관에 의뢰하여 프리세팅 시험 및 완제품 성능 시험을 실시하여 그 성능을 검증하였다. 성능 시험 결과 곡률에 따른 프리세팅이 가능함을 확인 하였다. 또한, 곡률형 프리세팅을 적용한 펜들럼 면진받침이 구조적으로 안전함을 확인하였다.

본 연구는 유색과 백색품종 토종오리의 성별에 따른 생산능력과 도체특성을 평가하고자 실시하였다. 1일령 토종오리 총 480수를 2개 품종(유색과 백색)×2개 성별(암컷과 수컷)로 총 4처리구의 4반복으로 반복 당 30수씩 평사에 나누어 8주간 사양실험을 진행하였다. 본 연구결과, 전체 사양실험기 간에서 토종오리의 체중, 증체량 및 사료섭취량은 품종(유색과 백색) 간 차이는 없었으나 수컷이 암컷보다 유의적으로 높았다(p<0.05). 이와 유사하게, 사료요구율은 유색품종과 백색품종의 차이가 없었으나 수컷이 암컷에 비해 유의적으로 개선됨을 확인하였다(p<0.05). 토종오리의 머리, 가슴육, 다리육 및 간의 무게는 처리구간 통계적 차이를 나타내지 않았다. 도체중량은 처리구간 차이가 없었으나, 도체율은 백색품종이 유색품종과 비교해 현저히 높았다(p<0.05). 또한 복강지방 무게는 수컷이 암컷에 비해 높았으며(p<0.05) 백색품종이 유색품종보다 높았다(p<0.05). 폐사율은 토종오리 의 품종과 성별에 따른 유의적 차이가 없었다. 본 연구결과는 토종오리의 육성기 단계에서 사육성적에 대한 기초자료로 이용될 것으로 사료된다.

Taguchi method is one of the most popular approaches for design optimization such that performance characteristics become robust to uncontrollable noise variables. However, most previous Taguchi method applications have addressed a single-characteristic problem. Problems with multiple characteristics are more common in practice. The multi-criteria decision making(MCDM) problem is to select the optimal one among multiple alternatives by integrating a number of criteria that may conflict with each other. Representative MCDM methods include TOPSIS(Technique for Order of Preference by Similarity to Ideal Solution), GRA(Grey Relational Analysis), PCA(Principal Component Analysis), fuzzy logic system, and so on. Therefore, numerous approaches have been conducted to deal with the multi-characteristic design problem by combining original Taguchi method and MCDM methods. In the MCDM problem, multiple criteria generally have different measurement units, which means that there may be a large difference in the physical value of the criteria and ultimately makes it difficult to integrate the measurements for the criteria. Therefore, the normalization technique is usually utilized to convert different units of criteria into one identical unit. There are four normalization techniques commonly used in MCDM problems, including vector normalization, linear scale transformation( max-min, max, or sum). However, the normalization techniques have several shortcomings and do not adequately incorporate the practical matters. For example, if certain alternative has maximum value of data for certain criterion, this alternative is considered as the solution in original process. However, if the maximum value of data does not satisfy the required degree of fulfillment of designer or customer, the alternative may not be considered as the solution. To solve this problem, this paper employs the desirability function that has been proposed in our previous research. The desirability function uses upper limit and lower limit in normalization process. The threshold points for establishing upper or lower limits let us know what degree of fulfillment of designer or customer is. This paper proposes a new design optimization technique for multi-characteristic design problem by integrating the Taguchi method and our desirability functions. Finally, the proposed technique is able to obtain the optimal solution that is robust to multi-characteristic performances.

항만 내 선박과 부두의 사고를 예방하기 위하여 통항 및 접안 안전성 평가를 통하여 안전한 부두가 건설되어 관리하고 있으나, 선 박의 접안 및 계류 과정에서 선박이 부두에 충돌하거나 로프로 인한 인명사고의 발생 등 예측할 수 없는 사고들이 종종 발생한다. 자동계류장 치는 선박의 신속하고 안전한 계류를 위한 자동화된 시스템으로 로봇 매니퓰레이터와 흡착 패드로 구성된 탈/부착 메커니즘을 가지고 있다. 본 논문은 자동계류장치의 흡착 패드의 위치 및 속도제어에 필요한 선체와의 변위 및 속도 측정 시스템을 다룬다. 자동계류장치에 적합한 측 정 시스템을 설계하기 위하여, 본 논문은 우선 센서의 성능 및 실외 환경적 특성 분석을 수행한다. 다음으로 이러한 분석 결과를 토대로 실외 부두환경에서 설치되는 자동계류장치에 적합한 변위 및 속도 측정시스템의 구성 및 설계 방법에 대해 기술한다. 또한 센서의 측정상태 감지 및 속도 추정을 위한 알고리즘을 제시한다. 제안된 방법은 다양한 속도 구간에서의 변위 및 속도 측정 실험을 통해 그 유용성을 검증한다.

This study investigated the changes in the cyanogenic glycoside (CN-Glc) content of maesil chung (MC) prepared according to its preparation conditions (i.e., maesil part, sugar type, maesil-sugar mixing ratio, liquid separation) and sugaring-ripening period and the quality characteristics of their products finalized through filtration and heat treatment (85oC, 30 min) with the 6-month ripened MC. The CN-Glc content dramatically decreased when the maesil flesh, isomaltooligosaccharide, maesil:sugar ratio of 5:5, and liquid separation after the 4-month sugaring were applied to the MC production. The CN-Glc content decreased with the ripening period. There was no effect of filtration and heat treatment on the CN-Glc reduction of the MC product. The sugar type predominantly affected the soluble solid and total carbohydrate content of the MC products, and their contents increased in the order of high-fructose corn syrup > sucrose > isomaltooligosaccharide. The MC product at a maesil:sugar ratio of 6:4 exhibited the higher organic acid content. There was no direct association between the total polyphenolic compound content and the preparation conditions of the MC product. Overall, the use of maesil flesh as a maesil ingredient and more than 6-month ripening after liquid separation may be a pivotal factor in producing the cyanogenic glycoside-reduced maesil chung.

The objective of this study was to investigate changes in the cyanogenic glycoside (CN-Glc) content of apricot and plum chungs over the sugaring-ripening period and to evaluate their quality characteristics. The whole and flesh parts of the apricot and plum were mixed with sugar to a mixing ratio of 1:1 (w/w) to prepare their chungs, after which the fruit-sugar mixtures were stored for 13 months. The CN-Glc content dramatically increased within 3-4 months, reached the maximum, and gradually decreased over storage by 13 months. The apricot and plum chungs with seeds exhibited much higher CN-Glc contents than those without seeds. All chungs stored for 10 months were filtrated and treated for 30 min at 85oC to measure their quality characteristics. Similar soluble solid contents (53.4- 53.6oBx) were found in all chungs. The apricot and plum chungs without seeds exhibited the higher concentrations of total carbohydrate, organic acid, and total polyphenolic compounds than those with seeds. In addition, the color of the apricot and plum chungs without seeds was darker and deeper yellow than those with seeds. Overall, the apricot and plum flesh may be better for producing the stone fruit chungs with minimal CN-Glc content and better nutrition.

전기자동차의 빠른 확산은 지구온난화와 자연재해 대응을 위해 국제적으로 중요한 과제이다. 대중화를 위해 “캐즘(Chasm) 극복”은 필수적이나, 선행연구들은 전기차 초기시장 분석이 대부분이며 캐즘 단계의 연구는 다소 제한적이다. 본 연구는 전기차 초기 단계를 벗어나는 국내시장에서 소비자의 전기차 구매 주요 저해 요인과, 이에 영향을 주는 소비자의 인구통계학적 특성 및 자동차 관련 경험을 설문과 통계 기법을 통해 심층 분석하였다. 연구 결과, 한국 전기차 시장은 캐즘 전 단계로 판단되며, 전기차의 “기술에 대한 낮은 신뢰성”, “경제성에 대한 의문”, “충전-운전 불편성”이 전기차의 주요 수용 저해 요인으로 확인되었다. 지역에 따른 고속/완속 충전 인프라의 적절한 구축, 교육과 홍보를 통한 전기차의 인식개선, 전기차 수용에 우호적인 얼리어답터(Early adopter)의 전기차 수용 촉진은 캐즘을 극복하는 과정에서 중요한 역할을 할 것으로 판단된다.

Radioactive contamination distribution in nuclear facilities is typically measured and analyzed using radiation sensors. Since generally used detection sensors have relatively high efficiency, it is difficult to apply them to a high radiation field. Therefore, shielding/collimators and small size detectors are typically used. Nevertheless, problems of pulse accumulation and dead time still remain. This can cause measurement errors and distort the energy spectrum. In this study, this problem was confirmed through experiments, and signal pile-up and dead time correction studies were performed. A detection system combining a GAGG sensor and SiPM with a size of 10 mm × 10 mm × 10 mm was used, and GAGG radiation characteristics were evaluated for each radiation dose (0.001~57 mSv/h). As a result, efficiency increased as the dose increased, but the energy spectrum tended to shift to the left. At a radiation dose intensity of 400 Ci (14.8 TBq), a collimator was additionally installed, but efficiency decreased and the spectrum was distorted. It was analyzed that signal loss occurred when more than 1 million particles were incident on the detector. In this high-radioactivity area, quantitative analysis is likely to be difficult due to spectral distortion, and this needs to be supplemented through a correction algorithm. In recent research cases, the development of correction algorithms using MCNP and AI is being actively carried out around the world, and more than 98% of the signals have been corrected and the spectrum has been restored. Nevertheless, the artificial intelligence (AI) results were based on only 2-3 overlapping pulse data and did not consider the effect of noise, so they did not solve realistic problems. Additional research is needed. In the future, we plan to conduct signal correction research using ≈10×10 mm small size detectors (GAGG, CZT etc.). Also, the performance evaluation of the measurement/analysis system is intended to be performed in an environment similar to the high radiation field of an actual nuclear facility.

At domestic nuclear power plant, concrete containers are stored to store waste generated before waste acceptance criteria (WAC) was established. Concrete container store concentrated waste liquid and waste resin. In order to disposal radioactive waste to a disposal site, it is necessary to conduct a characteristic evaluation inside the waste to check whether it satisfies the WAC. Two types of concrete containers are stored: round and square. The round type is filled with one 200-liter drum, and the square type is filled with four 200-liter drums. In the case of a round shape, the top lid is fastened with bolts, so it is possible to collect samples after opening the top lid without the need for additional equipment. However, in the case of a square shape, there is no top lid, and concrete is poured to cure the lid, so the separate equipment for characteristic evaluation is required. It is necessary to install a workstation for sample collection on the top of the concrete container, equipment for coring the top of the concrete container, and a device to prevent concrete dust scattering. Currently, the design of equipment for evaluating the characteristics of concrete containers has been completed, and equipment optimization through mock-up test will be performed in the future.

Dry active wastes (DAWs) are combustible waste generated during the operation and decommissioning of nuclear facilities, and are known to be generated in the amount of approximately 10,000 to 40,000 drums (based on 200 L) per unit. It consists of various types of protective clothing, paper, and plastic bags, and is stored in radioactive waste storage facilities. Therefore, reducing the volume of DAWs is an important issue in order to reduce storage costs and utilize the limited space of waste storage facilities. Heat treatment such as incineration can dramatically reduce the volume of waste, but as the waste is thermally decomposed, CO2, a global warming gas, is generated and there is a risk of emissions of harmful gases including radionuclides. Therefore, a heat treatment process that minimizes the generation of CO2 and harmful gases is necessary. One of the alternatives to incineration is to carbonize DAWs, dispose of carbonized materials below the release standard as non-radioactive waste, and selectively separate and stabilize inorganic components, including radionuclides, from carbonized DAWs. In this study, 13 types of DAWs generated from nuclear power plants were selected and their thermal decomposition characteristics were investigated to design a heat treatment process that replaces incineration. As a result of TGA analysis, the temperature at which thermal decomposition of each waste begins is 260-300°C for cotton, 320-330°C for paper, 315-420°C for synthetic fiber, 350°C for latex gloves. The mass of most samples decreased to less than 1 % of the initial weight after heat treatment, and dust suit and latex gloves had residues of 13.83% and 13.71% of the initial mass, respectively. The metal components of the residue produced after heat treatment of the sample were analyzed by EDS. According to the EDS results, cotton contains Ca and Al, paper contains Ca, Al and Si, synthetic fiber contains Ca, Cu and Ti, latex gloves contain Ca and Mg. Additionally, ICP analysis was performed to quantify the inorganic components. These results are expected to be applicable to the processing of DAW generated at nuclear facilities in the future.

A lot of CANDU Spent Fuels (CSFs) have been stored in spent nuclear fuel pools and dry storage facilities. In accordance with the enhanced nuclear regulations, the initial characteristics of CSF should be inspected to ensure the integrity of CSF and the reliable operation of storage system before loading it into a cask for long-term dry storage. For the inspections, an initial characteristics measurement equipment was designed, which is used for Pool-Side Examination (PSE) in the spent fuel pool of the pressurized heavy water reactor nuclear power plant. Measurements using the equipment consist of non-contact inspections and contact inspections. The non-contact inspections do not affect CSF integrity, whereas the integrity of CSF can be reduced during the contact inspections under abnormal operating conditions because the probe of equipment may apply specific loads to the CSF. Therefore, the structural integrity evaluations of equipment and CSF are performed using Finite Element (FE) analyses for four combinations based on two abnormal conditions and two probe positions. The used abnormal conditions are the pressing load condition and the scratching load condition, and two probe positions are the center and bottom of the fuel rod in the longitudinal direction, respectively. In this evaluation, the bottoms of the fuel rod or CSF are defined as the regions facing the bottom surface of equipment. The analysis of the pressing load condition is performed by pressing the probe of the equipment in radial direction of the CSF fuel rod. That of the scratching load condition is carried out by applying a specific radial load to the CSF fuel rod using the probe and then applying the load to the surface of the fuel rod while moving axially along the surface. All combinations are analyzed considering geometric, boundary and material non-linearity under the dynamic load, which is dependent on the equipment operating velocity. The stresses of CSF and equipment components were obtained from these analyses. The maximum stress of each component was generated at the combination on the scratching load condition for the bottom position among the four combinations. The obtained maximum stresses are lower than the yield stress for each component material. Also, the CSF is not overturned due to the support plate of the equipment in all analyses. Therefore, the structural integrity and safety of the equipment and the CSF are maintained under abnormal operating conditions during the inspection using the initial characteristic measurement equipment.

In this study, Sparassis crispa(cauliflower mushroom), which is rich in beta-glucan, was pulverized using ultrafine grinding technology for its potential utilization as a diverse food ingredient. The physical and antioxidant properties of cauliflower mushroom powder were evaluated at various grinding times. The results showed that as the grinding time of cauliflower mushroom increased, the average particle size significantly decreased (p<0.05). Additionally, the water-holding capacity, swelling capacity, and water solubility index of cauliflower mushroom increased significantly(p<0.05). Based on the analysis mentioned above, cauliflower mushroom prepared as a superfine powder for 5 minutes exhibited superior physical and chemical properties as well as antioxidant characteristics and is expected to be widely used in various foods.

Recently, universities of fisheries and institutions related to fisheries are actively carrying out a project to build new fisheries training ships. These new fisheries training ships are significantly larger in size and longer in length than the previous ships. In addition, these new ships basically have space that can accommodate more than 100 crew and passenger. On the other hand, they are excluded from IMO maneuverability evaluation since the size of these ships are still less than 100 m in length (LBP). These results have had an impact on the study of maneuverability of fishing vessels including the fisheries training ships. Against these backgrounds, the authors conducted a study to estimate the maneuvering characteristics of fisheries training ship Baek-Kyung according to depth in order to prepare a maneuvering characteristic index that enables the large fisheries training ships to navigate more safely using a modified empirical formula. It was confirmed that the maneuvering characteristics of Baek-Kyung changed significantly as the values of the hydrodynamic force coefficients changed as the water depth gradually decreased from around 1.5 (approx. 8 m in depth) of the ratio of the water depth to the ship draft. The results of this study will not only help navigators understand the maneuvering characteristics of Baek-Kyung, but also serve as an indicator when navigating in shallow water. In addition, the accumulation of these results will serve as a basis for future study on maneuverability of fishing vessel types.

We investigated an emerging magnetic loop dynamically formed on the Sun, which has the effective footpoint heating source that may play a key role in heating a solar atmosphere with free magnetic energy in it. It is suggested that the heating source could be related to local compression of a plasma in the emerging loop by means of Lorentz force, which converts the magnetic energy to the internal energy of the plasma that is used to reaccelerate a decelerated downflow along the loop, eventually generating the source when the kinetic energy of the downflow is thermalized. By analyzing very high-cadense data obtained from a magnetohydrodynamic simulation, we demonstrate how the local compression is activated to trigger the generation of the heating source. This reveals a characteristic of the emerging loop that experiences a dynamic loop-loop interaction, which causes the local compression and makes the plasma gain the internal energy converted from the magnetic energy in the atmosphere. What determines the characteristic that could distinguish an illuminated emerging loop from a nonilluminated one is discussed.

An all-perovskite oxide heterostructure composed of SrSnO3/Nb-doped SrTiO3 was fabricated using the pulsed laser deposition method. In-plane and out-of-plane structural characterization of the fabricated films were analyzed by x-ray diffraction with θ-2θ scans and φ scans. X-ray photoelectron spectroscopy measurement was performed to check the film’s composition. The electrical transport characteristic of the heterostructure was determined by applying a pulsed dc bias across the interface. Unusual transport properties of the interface between the SrSnO3 and Nb-doped SrTiO3 were investigated at temperatures from 100 to 300 K. A diodelike rectifying behavior was observed in the temperature-dependent current-voltage (IV) measurements. The forward current showed the typical IV characteristics of p-n junctions or Schottky diodes, and were perfectly fitted using the thermionic emission model. Two regions with different transport mechanism were detected, and the boundary curve was expressed by ln I = -1.28V - 13. Under reverse bias, however, the temperature- dependent IV curves revealed an unusual increase in the reverse-bias current with decreasing temperature, indicating tunneling effects at the interface. The Poole-Frenkel emission was used to explain this electrical transport mechanism under the reverse voltages.

본 연구에서는 공정 간소화, 균일한 나노 입자 형성, 백금 저감 및 활용도를 높이기 위하여 원자층 증착법 (Atomic Layer Deposition, ALD)을 통하여 양이온 교환막 연료전지용 촉매를 제조하고 증착 온도에 따른 백금 입자 형성 거동 을 확인하였다. 증착 온도는 250 °C, 300 °C, 350 °C로 조절하여 백금 촉매를 형성하였으며 각 각의 촉매의 증착 양 상을 확인하기 위하여 Thermogravimetric analysis, X-ray diffraction 및 Transmission electron microscopy를 도입하여 담지량, 백금 입자 분포, 크기 및 결정구조 등을 확인하였다. 합성된 백금 촉매를 연료전지에 적용하기 위해서 Cyclic Voltammetry 기법을 통해서 전기화학적 활성 표면적를 구하고, Membrane Electrode Assembly 셀을 제작하여 전지 특성을 확보하였다. 최종적으로, 백금 촉매 제조 시 ALD 증착 온도는 300 °C 이하에서 합성해야 됨을 밝혀냈으며, ALD으로 제작된 백금 촉매가 기존 습식 촉매보다 더 우수한 특성을 보임을 확인하였다. 해당 연구는 ALD을 통하여 다양한 접근법으로 촉매를 제조할 시, 기본적인 ALD 공정 정보 및 ALD 촉매 합성 방향성을 제공할 수 있다.