In this study, ultra-fine soft-magnetic micro-powders are prepared by high-pressure gas atomization of an Fe-based alloy, Fe-Hf-B-Nb-P-C. Spherical powders are successfully obtained by disintegration of the alloy melts under high-pressure He or N2 gas. The mean particle diameter of the obtained powders is 25.7 μm and 42.1 μm for He and N2 gas, respectively. Their crystallographic structure is confirmed to be amorphous throughout the interior when the particle diameter is less than 45 μm. The prepared powders show excellent soft magnetic properties with a saturation magnetization of 164.5 emu/g and a coercivity of 9.0 Oe. Finally, a toroidal core is fabricated for measuring the magnetic permeability, and a μr of up to 78.5 is obtained. It is strongly believed that soft magnetic powders prepared by gas atomization will be beneficial in the fabrication of high-performance devices, including inductors and motors.

The objective of this study was to investigate the effect of sample presenting types on the sensory characteristics of chilled buckwheat noodle soup (Naeng-myeon). Generic descriptive analysis was performed for evaluating only stock (system 1), only noodle (system 2) and stock with noodle (system 3). Eight kinds of commercially available Naeng-myeon were samples of interest. Ten female descriptive panelists participated. ANOVA and regression analysis were used for data analysis. In the training sessions, ten sensory properties were developed for system 1, four were additionally established for noodle. In each system, the 8 products showed significantly different intensities in almost all sensory attributes like darkness of stock, overall flavor, sweetness, saltiness, sourness. When integrating the two systems, sample presenting types showed significant difference for the seven sensory attributes, especially saltiness, sourness, beef flavor tended to be rated more strongly in system 1 than system 3.

The study analyzed performance assessment factors of VOCs odor sensors from 3 different manufacturers, such as minimum detection limit, humidity stability and temperature stability. Through the minimum detection limit assessment, it was found that a VOCs sensor was able to detect TVOCs at the concentration of 5 ppb. The standard deviation ratio was over 10%, and it increased as humidity rose. The range of temperatures in which the VOCs odor sensor using photoionization could operate was between 25oC and 40oC, and the sensor output values were unstable at low temperatures. In terms of the temperature stability of the metal oxide semiconductor sensor for measuring complex odors, the sensor output values dropped considerably to 0~10oC, and were similar to the concentrations of odorous gases generated at 25oC. The results of the test of VOCs odor sensor outputs after temperature and humidity pre-treatment revealed that the respective stable output values at 50% humidity and 25oC were similar to the concentrations of manufactured odors. In terms of temperature and humidity stability of the VOCs odor sensors, all target VOCs substances had stable output values at 25oC to 40oC and at 50% to 65% relative humidities, and unstable values at low temperatures and high humidities. Therefore, the implementation of pre-treatment systems including temperature and humidity correction (25~40oC, 50~65% RH) is required for the stable use of VOCs odor sensors.

Silver nanomaterials have been intensively applied in consumer products of diverse industrial sectors because of their strong biocidal properties and reported to be hazardous to aquatic organisms once released in the environment. Nanomaterials including sliver, are known to be different in toxicity according to their physicochemical characteristics such as size, shape, length etc. However studies comparing toxicity among silver nanomaterials with different physicochemical characteristics are very limited. Here, toxicities of silver nanomaterials with different size (50, 100, 150 nm), length (10, 20 μm), shape (wire, sphere), and coating material (polyvinylpyrrolidone, citrate) using OECD test guidelines were evaluated in aquatic species (zebrafish, daphnia, algae) and compared. On a size property, the smaller of silver nanomaterials, the more toxic to tested organisms. Sphered type of silver nanomaterials was less toxic to organisms than wired type, and shorter nanowires were less toxic than longer ones. Meanwhile the toxic effects of materials coated on silver nanomaterials were slightly different in each tested species, but not statistically significant. To the best of our knowledge, it is first investigation to evaluate and compare ecotoxicity of silver nanomaterials having different physicochemical characteristics using same test species and test guidelines. This study can provide valuable information for human and environmental risk assessment of silver nanomaterials and guide material manufacturers to synthesize silver nanomaterials more safely to human and environment.

White button mushroom (Agaricus bisporus) is the most widely consumed mushroom in the world, and domestic consumption is increasing owing to expansion of the westernized diet in recent years. Before 2000, most Korean mushroom farmers cultivated foreign varieties, but recently, Korean breeders are developing hybrid strains using molecular breeding tools. To produce a better mushroom cultivar, we evaluated some traits of button mushroom Agaricus bisporus strains. Mycelial growth rate at different culture temperatures was investigated by 25>20>15>30>10oC. Recently developed domestic varieties had superior mycelial growth rate compared to the traditionally grown species. In particular, the ASI1338 strain showed excellent mycelial growth rate at different temperatures. Further, we confirmed that ASI1007, ASI1085, ASI1310, ASI1339 were strongly resistant to bacterial brown blotch, whereas ASI1053, ASI1103, ASI1140, ASI1146, ASI1177, ASI1183, ASI1195, ASI1321, ASI1331, ASI1336 were relatively weakly resistant. The average number of days for 16.5, and that for harvest was 5.7; the average yield was 142.7 g/2-kg bag. Mycelial growth rates at 10, 15, 20, 25oC were similar, but that at 30? was lower. The mushroom yield was highly correlated with the number of days for pinheading and harvest.

CFRP hardened by carbon fiber and resin has the property of high strength and low weight. Specifically, the strong feature against the external vibration environment is shown as CFRP is designed with the structure of multi-axes. So, CFRP in place of metal has been used at the various fields. CFRP specimens for mode Ⅱ are applied with the repetitive fatigue load in this study. These specimens have the fiber layer angles of 30°, 45° and 60°. The material properties of specimens are investigated with the result of fatigue fracture due to this load. As the study result, the smallest and largest reaction forces of 500 N and 540 N are shown at the layer angle of 30° and 60° respectively among these specimens. The separation of adhesive interface at 4000 fatigue cycles is happened earliest in case of the layer angle of 60°. But the separation of adhesive interface at 11000 fatigue cycles is happened latest in case of the layer angle of 45°. Through the result of fatigue property, it is thought that the basis data can be applied to evaluate the safety at CFRP structure applied with fatigue.

Ag nanoparticles are extensively studied and utilized due to their excellent catalysis, antibiosis and optical properties. They can be easily synthesized by chemical reduction methods and it is possible to prepare particles of uniform size and high purity. These methods are divided into vapor methods and liquid phase reduction methods. In the present study, Ag particles are prepared and analyzed through two chemical reduction methods using solvents containing a silver nitrate precursor. When Ag ions are reduced using a reductant in the aqueous solution, it is possible to control the Ag particle size by controlling the formic acid ratio. In addition, in the Polyol process, Ag nanoparticles prepared at various temperatures and reaction time conditions have multiple twinned and anisotropic structures, and the particle size variation can be confirmed using field emissions scanning electron microscopy and by analyzing the UV-vis spectrum.

The hydrogen embrittlement of two austenitic high-manganese steels was investigated using tensile testing under high-pressure gaseous hydrogen. The test results were compared with those of different kinds of austenitic alloys containing Ni, Mn, and N in terms of stress and ductility. It was found that the ultimate tensile stress and ductility were more remarkably decreased under high-pressure gaseous hydrogen than under high-pressure gaseous argon, unlike the yield stress. In the specimens tested under high-pressure gaseous hydrogen, transgranular fractures were usually observed together with intergranular cracking near the fracture surface, whereas in those samples tested under high-pressure gaseous argon, ductile fractures mostly occurred. The austenitic high-manganese steels showed a relatively lower resistance to hydrogen embrittlement than did those with larger amounts of Ni because the formation of deformation twins or microbands in austenitic highmanganese steels probably promoted planar slip, which is associated with localized deformation due to gaseous hydrogen.

Finite Element analysis were carried out to investigate the deformation behaviours of a buckled automotive seat frames made of three different types of materials, i.e., SAPH440, Al6082-T6 and Al7021-T7, when they were subject to external load, based on the ECE R14 regulation to achieve lightweight structure. Also, several thicknesses were applied to the seat frame structures of each material for characterising deformations. It was found that light weight seat frame structure was obtained compared to conventional steel structure when it was made of aluminium under the condition of satisfying ECE R14 regulation. Interpretation result, when changing from SAPHH440 material has a thickness of 1.5mm to Al material has a thickness of 3.0mm, that could checking weight lightening about 47%.

Damages of large embankment dams by recent strong earthquakes in the world highlight the importance of seismic security of dams. Some of recent dam construction projects for water storage and hydropower are located in highly seismic zone, hence the seismic performance evaluation is an important issue. While state-of-the-art numerical analysis technology is generally utilized in practice for seismic performance evaluation of large dams, physical modeling is also carried out where new construction technology is involved or numerical analysis technology cannot simulate the behavior appropriately. Geotechnical centrifuge modeling is widely adopted in earthquake engineering to simulate the seismic behavior of large earth structures, but sometimes it can’t be applied for large embankment dams due to various limitations. This study proposes a dynamic centrifuge testing method for large embankment dams and evaluated its applicability. Scaling relations for a case which model scale and g-level are different could be derived considering the stress conditions and predominant period of the structure, which is equivalent to previously suggested scaling relations. The scaling principles and testing method could be verified by modified modeling of models using a model at different acceleration levels. Finally, its applicability was examined by centrifuge tests for an embankment dam in Korea.

국내 양송이 재배품종의 다양성을 확보하기 위하여 육성되었던 ‘새도’ 등 5개 품종을 양송이 주산단지 5개 재배지역에서 농가현장시험을 통하여 품종의 특성을 평가하였다. 공시품종의 재배적 특성을 종합해보면 버 섯발생 및 버섯생육에 관련한 부분은 거의 비슷한 특성을 보였다. 전반적으로 균사세력은 비슷하였으나 재배 시험농가의 평가에서는 ‘새도’가 강한 편이며, ‘새한’이 약한 것으로 평가하고 있다. 자실체 개체중 특성은 품 종특성 보다는 퇴비의 영양 성분함량 및 발생량이 관여하였으며, 품종 중에서 갈색종이 가장 개체중이 높고, 백색종은 품종간의 차이를 구별할 수 없었다. 자실체 경도 특성은 품종 및 주기별 변화가 일정하지 않았고, 주기가 진행되면서 감소 또는 2주기에서는 증가하였다가 감소되였다. 자실체 부위별 경도는 대부분 갓이 대 보다 높은 편이었다. 자실체 색특성에서 갓이 대보다 명도가 높으며, 품종 간에 약간의 차이가 있었었으나 육안적으로 차이를 구분할 수 없었다. 채도 값은 황색 보다는 적색에 의해 좌우되며, 갓과 대가 유사하였다. 자실체 형태적 특성은 주기별 형태적 특성과 수확시기에 따른 차이가 클 것으로 추정되었다.

버섯 생산시설의 자동화와 규모화로 재배면적은 감소하나 생산량은 꾸준한 증가 추세이고 느타리, 큰 느타리, 팽이버섯 중심으로 특정품목에 편중 재배되고 있는 시점에 농가소득을 창출할 수 있는 새로운 유망버섯 발굴이 요구되고 있다. 따라서 전북농업기술원은 봉지재배에 적합한 버들송이 신품종을 육성 하고자 유전자원을 수집하고 유전적 다형성 분석과 자실체 특성평가를 한 결과는 다음과 같다. 수집균 주 43종의 5.8s rDNA의 ITS 영역의 총 염기수는 667~712bp 수준이었고, 염기서열 분석에 의한 계통분 류는 총 3그룹으로 분류되었다. 수집 유전자원 간 5.8s rDNA의 ITS 영역 상동성은 90~100% 수준이었는 데 97% 이상이 41 계통이었고 90% 상동성은 JB08030 등 2계통으로 평가되었으며, Agrocybe cylindracea (JB08001 등 24계통)등 3종류로 분류되었다. 특이사항은 백색의 자실체 특성을 가진 JB08018 계통이 갈 색 자실체 특성인 JB08010 등 다른 계통들과 rDNA 유사도에 있어서 100%의 유사도로 분석되었다. 이 는 자실체 갓 색깔을 결정하는 유전자의 위치는 5.8s rDNA 밖에 위치할 것으로 판단된다. 수집 유전자 원의 유전적 다양성과 자실체 품질특성(재배일수, 갓 색, 다수성)을 기준으로 단포자 교잡육종을 실시 하기 위해 JB08010 등 5계통을 선발하였고 교잡육종을 수행하였다.

팽이버섯 포장필름의 국산화 및 동남아시아 지역을 대 상으로 한 수출용 필름을 개발하기 위하여, 개발된 포장 필름을 현재 시중에 유통 중인 포장필름 및 수입산 포장 필름과 함께 저장 중 팽이버섯의 저장 온도별 품질변화에 이어 유리당, 유리아미노산, 구성아미노산 등에 대한 영양 학적 특성변화를 검토하였다. 유리당 함량을 분석한 결과, 저장 온도가 높아질수록 유리당 함량이 약간씩 증가하는 경향을 보였으나, 포장 필름의 종류에 따라서는 큰 차이 를 나타내지 않았다. 유리아미노산의 경우 저장온도가 올 라감에 따라 methionine은 증가하는 반면, tyrosine은 감 소하였다. Polyphenol oxidase의 활성 확인결과 본 과제 로 인해 개발된 포장지가 우수함을 확인하였다. 베타글루 칸 함량은 건강 기능성 식품의 표준 지표로 사용되는 성 분이나 버섯 저장성을 판단하는 지표로 사용하기에는 적 당하지 않을 것으로 여겨진다.

노후 콘크리트의 보수 방법에는 교량상판의 덧씌우기나 노후된 도로의 보수처럼 바닥판 또는 기존 콘 크리트를 보호함과 동시에 공용기간 중 콘크리트의 내구성 증진을 위하여 복합 구조체로 형성된 접착식 콘크리트 덧씌우기 포장이 일반적으로 사용되고 있으며, 이와 같은 복합 구조체는 신･구 콘크리트 간 부 착력에 따라 공용 중 차량하중, 환경하중 하에서 일체화된 역학적 거동과 장기공용성 확보에 커다란 영향 을 받게 된다. 이처럼 공용성 확보를 위한 중요인자인 부착강도를 평가하는 대표적 시험방법으로는 쪼갬 인장시험, 경사전단시험, Pull-out시험 및 니플 파이프 직접인장시험 등 다양한 시험법으로 사용되고 있 으나, 실내시험에 국한된다는 한계성을 지니고 있어 실내 및 현장평가에 동시 적용이 가능한 직접인발 시 험법이 가장 널리 사용되고 있다. 직접인발 시험법에 있어 실내 부착강도 평가의 경우 KS F 2762 「콘크 리트 보수보호재의 접착 강도 시험방법」을 준용하고 있으나, 현장 부착강도 평가의 경우는 유일하게 한국 도로공사에서 시행하고 있는 품질성능평가(QPI)에 의거하여 시행되고 있다. 실내 부착강도 시험에서는 규정된 밑판과 시험체를 사용할 경우 세장비(포설두께/코어직경)를 일정하게 유지하여 정량적 평가를 할 수 있으나, 구조물에 대한 유지보수공사 시 열화정도 및 구조물 특성 상 포설두께를 전 구간에 걸쳐 일정 하게 유지할 수 없어 현장 부착강도 평가 시 실내와 달리 세장비를 일정하게 유지하는 것이 어려운 실정 이다. 압축강도 및 인장강도의 경우 많은 연구를 통하여 시편의 세장비에 따른 강도변화와 이를 보정하기 위한 보정계수가 제안되어 사용되고 있으나 현장 부착강도의 경우 세장비의 편차가 압축강도 및 인장강도 시편보다 매우 큼에도 불구하고 현장 부착강도 시편의 세장비 차이에 따른 영향을 고려하지 못하고 있는 실정이다. 따라서 본 연구에서는 압축강도 및 인장강도에서와 같이 시편의 세장비가 부착강도에 미치는 영향을 분석하고자 실내 및 현장 부착강도를 다양한 조건하에 실시하였으며 이를 통해 부착강도 평가 시 세장비에 따른 보정계수를 도출하고자 하였다. 세장비 효과 및 보정계수를 산출하기 위하여, 실내 부착강도 시험법의 포설두께 및 코어직경을 표준비 율(1.0)로 선정하여 세장비 0.5, 1.0, 1.5, 2.0 등 총 4가지 변수에 대한 시험을 진행하였다.