This paper presents a study of the tensile properties of austenitic high-manganese steel specimens with different grain sizes. Although the stacking fault energy, calculated using a modified thermodynamic model, slightly decreased with increasing grain size, it was found to vary in a range of 23.4 mJ/m2 to 27.1 mJ/m2. Room-temperature tensile test results indicated that the yield and tensile strengths increased; the ductility also improved as the grain size decreased. The increase in the yield and tensile strengths was primarily attributed to the occurrence of mechanical twinning, as well as to the grain refinement effect. On the other hand, the improvement of the ductility is because the formation of deformation-induced martensite is suppressed in the high-manganese steel specimen with small grain size during tensile testing. The deformationinduced martensite transformation resulting from the increased grain size can be explained by the decrease in stacking fault energy or in shear stress required to generate deformation-induced martensite transformation.

Small-size buildings are not designed by professional structural engineers in Korea. Therefore, their seismic performance can not be exactly estimated because their member sizes and reinforcement may be over- or under-designed. A prescriptive design criteria for the small-size buildings exists, but it also provides over-designed structural members since structural analysis is not incorporated, so it is necessary to revise the prescriptive criteria. The goal of this study was to provide an information for the revision, which is seismic performance and capability of small-size reinforced concrete moment frame buildings. For the study, the state of existing small-size reinforce-concrete buildings such as member size and reinforcement was identified by investigating their structural drawings. Then, over-strength, ductility and response modification factor of the small-size reinforced concrete moment frame buildings were estimated by analytical approach along with seismic performance check. The result showed that they possess moderate over-strength and ductility, and may use slightly increased response modification factor.

This study aims to estimate the species, size and shape of fish using a non-contact 3 dimensional pattern laser so that this preliminary test was carried out to understand the structural feature and length of goldfish according to water turbidity and depth in the aquacultural tank. 3-D pattern laser could clearly detect its morphological shape except the caudal fin due to soft tissue. Since the sensing strength of line laser light according to depth has sufficient power, it is possible to measure its depth and structural feature in the detected range. The result showed that the measured error of individual’s fork length was less than ±1% in the water using 3-D pattern laser, when compared with the measured value in the air.

The multi-layer combination provides a very narrow pore size distribution in a specific pore size range. By utilizing the multi-layer design equations developed for each individual layer of known pore properties, it is possible to design the multi-layer microfiltration media precisely to a tailor pore size distribution.

ZIF-8은 제올라이트형 이미다졸레이트 골격체(Zeolitic Imidazolate Framework, ZIF) 중 하나로 마이크로 기공이 잘 발달된 구조체이며, 기공의 크기는 3.4 Å 으로 기체 흡착 및 분리 소재로 연구되어지고 있다. 본 연구에서는 입자 형성에 용매가 미치는 영향에 대하여 알아보기 위하여 다양한 종류의 용매 조건에서 ZIF-8 입자를 제조하였으며 다공성의 α-알루미나 지지체 위에 나노 크기의 ZIF-8 입자를 코팅한 후 용매열합성법으로 분리막을 제조하였다. SEM, XRD, TGA, DLS 등의 분석을 통해 각 용매에서 합성된 ZIF-8 입자의 특성을 평가 및 기체 흡착 성능을 측정하였으며, 용매의 종류에 따른 분리막 형성에 대하여 SEM, XRD, 기체투과특성 등을 관찰하였다.

P-type ternary Bi0.5Sb1.5Te3 alloys are fabricated via mechanical alloying (MA) and spark plasma sintering (SPS). Different ball sizes are used in the MA process, and their effect on the microstructure; hardness, and thermoelectric properties of the p-type BiSbTe alloys are investigated. The phases of milled powders and bulks are identified using an X-ray diffraction technique. The morphology of milled powders and fracture surface of compacted samples are examined using scanning electron microscopy. The morphology, phase, and grain structures of the samples are not altered by the use of different ball sizes in the MA process. Measurements of the thermoelectric (TE) transport properties including the electrical conductivity, Seebeck coefficient, and power factor are measured at temperatures of 300- 400 K for samples treated by SPS. The TE properties do not depend on the ball size used in the MA process.

Most Korean companies in the fashion industry are SMEs, and the role of the CEO and management ownership is important for enhancing the firm’s competence and developing strategies. The study aims to examine the effect of management ownership on company financial growth. In particular, the study focuses on the moderating effect of company age and size on Korean fashion SMEs’ financial outcomes. Financial data based on company financial statements from 2012 to 2014 was collected by the Data Analysis, Retrieval and Transfer System of Korea’s Financial Supervisory Service. A total of 295 companies’ (domestic fashion businesses) data was analyzed by the bootstrap method. The median sales value in the financial year 2014 was 47,492,403,958 KRW, and the company size was divided by it. The companies were in business for an average of 20 years. According to the results, the management ownership had a negative effect on Compound Annual Growth Rate (CAGR) for the three-years, and the relationship between the two variables was moderated by company age. Additionally, the interaction effect of management ownership and company age on 3-CAGR was also moderated by company size. When the companies had spent only a few years in business, a negative effect of management ownership for small firms and a positive effect of management ownership on financial growth for medium firms were found. These results suggest that small companies starting business need to manage their company governance structure to make flexible decisions, and after retaining financial growth, the companies can expand their businesses based on strong ownership.

본 연구에서는 개별요소해석 프로그램인 PFC3D를 이용하여 지오그리드와 재료입자 사이의 상관관계를 지오그리드 반복인장 시험 및 전단시험을 통해 확인 하고자 한다. 재료의 입도 유효입경 D50 (누과통과율 50%)을 기준으로 40mm, 30mm, 20mm, 15mm, 10mm 로 비교 하였고, 합성수지로 제작된 지오그리드 개별요소를 미시 물성치 보정을 통해 형성하였다. 반복인장에서는 변형률 0.5%를 최대 인장 변형률로 설정하여 반복인장을 500회 실시 하였으며, 전단 시험에서는 지오그리드 생성위치를 전단면으로 설정하였고 횡방향으로 변형률 10%까지 전단시켰다. 해석 결과 유효입경 20mm에서 가장 큰 보강효과를 확인 하였고, 40mm 및 30mm에서 보강효과가 감소되는 것을 확인하였다. 지오그리드의 격자 크기를 고려하였을 때, 재료의 유효입경의 크기는 격자의 내접원 직경의 60% 정도 확보 시 보강효과가 가장 좋은 것으로 확인하였다.

Nanoparticles are widely used in various fields such as electronics, medicines and getting focus on the application in food industry for developing intelligent delivery system with bioactive ingredients or functional nutrients. Basic study on possible toxicological effect of food applicable nanoparticles is required for a practical application in food industry. In this study, size-controlled bovine serum albumin (BSA) nanoparticles were prepared by a desolvation method and their cytotoxicity was investigated. BSA nanoparticles were prepared with mean diameters as 115, 137, 159, and 299 nm, then cytotoxicity was evaluated with RAW 264.7 macrophages as in vitro model. Cell viabilities were significantly affected as increasing nanoparticle concentration. Smaller the sizes of nanoparticles, LD50 values were significantly reduced. LD50 values of BSA nanoparticles were 50, 65, 126, and 170 μg/ml, respectively. Nanoparticle was supposed to induce the apoptosis of RAW 264.7 marcrophages and underlying mechanism will be investigated in future. These findings will be used as valuable basement for nanofood development with BSA nanoparticles.

The objective of this study was to evaluate size-different chitosan nanoparticles as a CO2 indicator. CO2 gas is dissolved to form H2CO3 which makes the solution acidic. Chitosan is acid soluble and its appearance (turbidity) changes depending on pH in aqueous solution. Two size-different chitosan nanoparticles were fabricated by ionic gelation between chitosan (0.30 and 0.50%, w/v) and 0.07% sodium tripolyphosphate (TPP) solution. The sizes of chitosan nanoparticles were 630.77 and 1194.87 nm, respectively. To investigate the effect of chitosan nanoparticles as CO2 indicator, the initial pH of chitosan nanoparticle suspension was adjusted to 8.0. Thereafter, 100% CO2 gas was injected into the chitosan nanoparticle suspension, and the changes of pH and absorbance (600 nm of absorption wavelength) of the suspension over time were measured for 28 min. Absorbance at the appearance transition and its corresponding time was calculated using logistic function (R2> 0.99).As a result, pH of chitosan nanoparticle suspension decreased rapidly under CO2 gas injection for 10 min and finally reached around 6.0. In addition, there was significant difference in appearance transition time which was6.62 and 12.45 min for small- and large-sized chitosan nanoparticle suspensions, respectively. This study suggests that chitosan nanoparticle suspension might be useful as a food quality indicator for CO2 emitting foods such as fermented foods.

Most ectotherms mature at a larger body size in colder conditions. This negative relationship between developmental temperature and final body size is termed the temperature-size rule. In this study, we investigated how dietary protein:carbohydrate (P:C) balance modulates the fundamental relationship between temperature and body size in the final-instar caterpillars of Spodoptera litura. The magnitude and sign of the thermal reaction norm for body size were altered by the dietary P:C balance of the food eaten by caterpillars. The slope of the reaction norm was flat for caterpillars raised on a nutritionally balanced food (P:C = 1:1) but was negative for those on imbalanced foods (1:5 or 5:1). When allowed to self-compose their preferred diet, caterpillars preferred carbohydrate-rich food at higher temperatures. The negative impact of high temperature on body size was mitigated by such a temperature-driven shift in nutrient preference. This study highlights the importance of macronutrient balance as a key factor modulating the relationship between temperature and body size in insects.

목 적: 동공크기가 일정하게 증가할 때 나타나는 굴절력 변화를 측정하여 분석하였다. 방 법: 백내장이나 안질환 및 시력교정수술 등의 경력이 없는 근시 50명(100안), 원시 9명(17안)을 대상 으로 하였다. 암순응상태의 동공크기 검사는 Colvard pupillometer(OASIS medical, USA)를 사용하였다. 굴절력은 Zywave(Baush & Lomb, USA)를 사용하여 측정하였다. 동공크기가 3.0mm에서 6.0mm까지 0.5mm씩 증가할 때 굴절력 값을 분석하였다. 동공크기에 따른 굴절력 변화는 ANOVA를 사용하였고, 상관 분석을 하여 변수들 간의 연관성을 보았다. 결 과: 평균연령은 44.05±11.91세(25~64세), 암순응상태의 동공크기는 6.57±0.52mm로 나타났다. 나 이가 증가할수록 암순응상태의 동공크기가 작았다(p=0.000). 동공크기(3.0~6.0mm)에 따른 등가구면굴절 력의 변화는 근시의 경우 -0.52±0.48 D로 근시의 증가를 보였고, 원시의 경우 0.81±0.34 D로 원시의 감 소를 보였다. 근시의 경우 동공크기에 따라 등가구면굴절력이 -0.23±0.23D(3.0mm에서 4.5mm)와 -0.29±0.30 D(4.5mm에서 6.0mm)로 변하였다. 근시에 있어서 등가구면굴절력 변화량은 나이가 증가할수 록 많았다(p=0.008). 결 론: 동공 크기의 증가로 인해 안구 굴절력은 근시안의 근시를 증가시키고 원시안의 원시는 감소하는 것으로 나타났다. 상관분석 결과 나이가 증가할수록 암소시일 때의 동공크기 변화가 작아지고 근시일 때의 굴절력 변화가 많은 것으로 나타났다

This study was conducted the comparative analysis on quality and rice bread process suitability properties by four particle size classification of dry-milled flours for four rice varieties. Dry-milled rice flours were prepared by dry milling and classified according to particle size using 100, 150, 200, and 250 mesh sieves. The mean particle size by four particle size classification of 60 ~ 100 mesh, 100 ~ 150 mesh, 150 ~ 200 mesh, 200 ~ 250 mesh exhibited 118.9 μm, 87.4 μm, 65.3 μm, 46.1 μm, respectively. The particle size of dry-milled rice flours was the finer, the damaged starch content was the higher (r = − 0.570*). The particle size also had significant negative correlation with the water absorption index (r = − 0.533*, r = − 0.593*), and water solubility index (r = − 0.857**, r = − 0.584*). Dry-milled rice flours with particle size of 60 ~ 70 μm, passed through 150 and 200 mesh sieves exhibited the highest specific volume of rice bread. Whereas, the dry-milled rice flour with finer particle size above 200 mesh showed the lowest specific volume of rice bread. These results will be applied as a quality standard to aid in the selection of the most suitable dry-milled rice flour for baking.

This study was conducted to analyze fishing capacity and bycatch by mesh size and entrance size of spring net pot conductedby water tank and field experiment. The water tank experiments were conducted by using traps with mesh size of 22 mm and entrance size of 120 mm and 140 mm, respectively in the water tank of NIFS. The field experiment was conducted using 5 kinds of spring net pot with mesh sizes of 20 mm, 22 mm, 35 mm and entrance size of 120 mm, 130 mm, 140 mm, 360 mm by coastal trap fishery vessel operating around the area of Geoje island. In the result of water tank experiments, the catch of conger eel was 1.5 times higher when using trap with entrance size of 140 mm than that of 120 mm. In the field experiment, when using same mesh size, the larger the entrance size, the higher amount of conger eel catch, bycatch and number of bycatch species. When using the same entrance size, the larger the mesh size, the lower amount of conger eel catch and number of bycatch species, whereas the amount of bycatch showed increasing trend.

PURPOSES : This study primarily focused on evaluating the performance characteristics of 4.75-mm nominal maximum aggregate size (NMAS) asphalt mixtures for their more effective implementation to a layered flexible pavement system. METHODS: The full-scale pavements in the FDOT’s accelerated pavement testing (APT) program, including 4.75-mm mixtures at the top with different thicknesses and asphalt binder types, were considered for the faster and more realistic evaluation of the rutting performance. The results of superpave indirect tensile (IDT) tests and hot-mix asphalt fracture mechanics (HMA-FM) based model predictions were used for cracking performance assessments. RESULTS: The results indicated that the rutting performance of pavement structures with 4.75-mm mixtures may not be as good as to those with the typical 12.5-mm mixtures, and pavement rutting was primarily confined to the top layer of 4.75-mm mixtures. This was likely due to the relatively higher mixture instability and lower shear resistance compared to 12.5-mm mixtures. The energy ratio (ER) and HMA-FM based model performance prediction results showed a potential benefit of 4.75-mm mixtures in enhanced cracking resistance. CONCLUSIONS : In relation to their implementation, the best use of 4.75-mm mixtures seem to be as a surface course for low-trafficvolume applications. These mixtures can also be properly used as a preservation treatment that does not necessarily last as long as 12.5-mm NMAS structural mixes. It is recommended that adequate thicknesses and binder types be considered for the proper application of a 4.75-mm mixture in asphalt pavements to effectively resist both rutting and cracking.

목 적 : 확산강조영상은 뇌신경계에서 ischemia, infarction, inflammation, infection, tumor등 다양한 병변을 진단하는데 유용하다. 하지만 척추 확산강조영상은 심장의 운동, 호흡이나 연하에 의한 움직임과 척추체가 가깝게 있어 자기화율의 급격한 변화 등의 이유로 distortion과 artifact가 많이 발생하여 좋은 영상을 획득하기 어려웠다. 확산강조영상에서 영상의 distortion과 artifact를 변화시킬 수 있는 인자는 SENSE factor와 voxel size이다. 따라서 본 논문에서는 흉추 확산강조영상에서 SENSE factor와 voxel size를 변화시켜 영상을 획득 후 이를 비교평가 하고, 영상의 distortion, artifact 줄여 진단적 가치를 높이는 것이 본 논문의 목적이다. 대상 및 방법 : 척추질환이 없는 건강한 지원자 10명(남자: 7, 여자: 3, 평균연령: 29.6세)을 대상으로 하였다. 검사장비는 Ingenia 3.0T MRI (philips medical system, Netherlands)를 사용하였고, 신호수집 코일은 DS posterior coil을 사용하였다. FOV 240×184, B-factor 0, 1000 s/mm², slice thickness 4 mm, NEX: 10, TR과 TE는 장비에서 제공하는 가장 짧은 값을 사용하고 SENSE factor를 1, 2, 3으로 설정 후각 SENSE factor에서 voxel size를 1×1, 2×2, 3×3 mm로 변화시켜 영상을 획득하였다. 정량적 평가는 T2/SAG영상을 기준으로 Thoracic Spine 6th body에서 spinal cord까지의 거리를 각각 측정하여 distortion을 평가 하였고, 정성적 평가는 영상의학과 교수 1명, MRI 전문 방사선사 2명이 5점 척도로 영상의 artifact, distortion, 병변 검출 능력 등 전체적인 영상의 질을 비교평가 하였다. 통계적 유의성은 Wilcoxon signed rank test(SPSS 18.0K for windows)를 통해 검정하였고 p-value는 0.01미만인 경우에 통계적으로 유의하다고 판정하였다. 결 과 : 고정된 SENSE factor에서 voxel size 변화에 따른 distortion의 정량적 평가결과 SENSE factor 1에서 voxel size가 1×1, 2×2, 3×3으로 변화할 때 기준점에서 측정한 10명의 지원자의 평균길이는 6.54 mm, 5.33 mm, 4.79 mm, SENSE factor 2에서 평균 4.22 mm, 3.33 mm, 3.14 mm, SENSE factor 3에서 평균 3.04 mm, 2.63 mm, 2.29 mm로 측정 되었다. 동일한 SENSE factor에서 voxel size가 3×3일 때 영상의 distortion이 가장 많이 감소되었으며 동일한 voxel size에서는 SENSE factor가 3일 때 영상의 distortion이 가장 많이 감소되었다. 정성적 평가에서는 distortion, artifact의 발생정도와 척추체와 척수에서의 병변 검출 능력을 5점 척도(평가 불가: 1, 나쁨: 2, 보통: 3, 좋음: 4, 아주 좋음: 5)로 평가하였다. SENSE factor 1, voxel size 1×1, 2×2, 3×3으로 변화할 때 평균 2.23점, 2.30점, 2.33점으로 비교적 낮은 점수를 받았고 SENSE factor 2, voxel size 1×1, 2×2, 3×3으로 변화할 때 평균 2.86점, 4.20점, 4.13점, SENSE factor 3, voxel size 1×1에서 3.10점, 2×2, 3×3에서 평균 4.66점으로 가장 진단 가치가 높은 영상으로 평가되었다. 각각의 SENSE factor와 voxel size의 변화에 따른 영상의 distortion의 감소의 통계적 유의성을 알아보기 위해 Wilcoxon signed rank test로 검정한 결과 모두 p<0.01 로 나타났다. 결 론 : 확산강조영상은 뇌 질환에서 뿐만 아니라 척추와 spinal cord lesion을 감별하는데 매우 유용하다. 임상에서 Thoracic spine 확산강조영상 검사 시 본 논문에서 실험하여 얻은 결과처럼 SENSE factor: 3, voxel size: 2×2 또는 3×3을 선택하여 영상을 획득한다면 영상의 artifact, distortion이 감소되어 진단적 가치가 높은 영상을 만들 수 있을 것으로 사료된다.