The silver nanofluids were synthesized by the pulsed wire evaporation (PWE) method in a liquid-gas mixture. The size and microstructure of nanoparticles in the deionized water were investigated by a particle size analyzer (PSA), transmission electron microscope (TEM), and scanning electron microscope (SEM). Also, the synthesized nanofluids were investigated in order to assess the stability of dispersion of nanofluid by the zetapotential analyzer and dispersion stability analyzer. The results showed that the spherical silver nanoparticle formed in the deionized water and mean particle size was about 50 nm. Also, when explosion times were in the range of 20~200 times, the absolute value of zeta potential was less than -27 mV and the dispersion stability characteristic of low concentration silver nanofluid was better than the high concentration silver nanofluid by turbiscan.

About 50,000 hives of Bombus terrestris are used for pollination of tomato and other economical crops (fruit vegetables and fruit trees) in Korea. Therefore this study was conducted to find out the effective use of B. terrestris and its economic effect in the major beefsteak-tomato cultivation areas from February to August in 2008. The pollinating activities, rate of bite-mark and lifespan of B. terrestris"s hive according to all beefsteak-tomato varieties (Super Momotaro, Zeus42, Mascara and Super Sunroad, 500 ㎡, 9,600～12,000plants) were apparent by regular supplement of pollen (5～6g/3 days) to the hive of B. terrestris. Especially, Super Momotaro and Super Sunroad variety were most distinctive in the effects by regular pollen supplement.

본 연구에서는 정서 유발 프로토콜을 이용하여 유발된 다섯 가지 정서(기쁨, 슬픔, 분노, 스트레스와 무료함)에 따른 아동의 심혈관계 반응의 차이를 밝히고자 하였다. 아동에게 음악, 색채, 심상을 유발하는 이야기, 인형으로 구성된 복합자극을 제시하는 동안 이들의 심혈관계 반응을 측정하고, 자극에 대한 적합성(유발된 정서의 유형)과 효과성(유발된 정서의 강도)을 정서평가척도 상에 평정하도록 하였다. 분석에 사용된 심혈관계 생리반응 변수는 심박수, 호흡주기 관련 심박률 변화, 심박률 분산, 심박률 분산의 고주파수 성분, 저주파수 성분과 혈류량이었다. 연구 결과, 스트레스 유발하는 자극을 제외한 네 가지 정서 유발 자극은 아동에게 각 정서(기쁨, 슬픔, 분노와 무료함)를 적절하고 효과적으로 유발시킨 것으로 나타났다. 또한 호흡주기 관련 심박률 변화를 제외한 모든 심혈관계 지표에서 정서에 따른 유의한 차이가 나타났다. 정서에 따라 특징적인 심혈관계 반응이 나타났으며, 이는 심혈관계 반응을 이용하여 아동정서를 구분하는 것이 가능함을 의미한다.

Safety is totally established through not only legal regulations and system but the establishment of safety culture. As a foundation of safety culture, safety and health communication is the essential condition. Therefore, in the case of researching safety culture the communication network of a organization is a crucial factor. This study has analysed the structure of occupational safety and health communication between domestic and foreign corporations comparatively by the statistical analysis. The occupational safety and health communication is composed of four sub-dimensions: general communication in working site, using safety information communication, communication with the board of directors, and communication with labor union. The nationality of corporations influences the safety communication significantly except for communication with labor union. Consequently it is possible to infer that the nationality of corporations is a significant factor for safety communication network.

Due to change of various marine environments according to seawater temperature rising, Japanese common squid(Todarodes pacificus), which was distributed in East Sea, was recently caught in Yellow Sea during a summer season from 2006. The fishery resources density research was carried out in Korea-China Provisional Water Zone using trawl fishing gear and acoustics in National Fisheries Research & Development Institute in Korea. This paper showed the analysis on the acoustical backscattering strength by two frequencies(38kHz, 120kHz) for Japanese common squid by acoustical scattering theoretical model based on size distribution for survey period, and estimate the density distribution for squid s integrated layer which was extracted from any scatterers distributed in water column using two frequency difference method which has been used to distinguish fish shoals or specific target scatterers from sound scattering layer which is composed of various zooplankton. Furthermore, the entire range of their density estimation was suggested using by Monte Carlo simulation under considering each uncertainty such as size distributions or swimming angle and so on in survey area.

This study shows that the distribution density of snow crab, Chionoecetes opilio, was estimated using an underwater video monitoring system attached on the towing sledge. The field experiments were carried out at the coastal waters around Chuksan, East Sea, where ranged from 110 to 130m depth during September and October 2007. The sledge was towed for 40 minutes and the towing speed was controlled between 1.5 to 1.7 knot and each research areas were calculated to multiply towed distance by the detection width of the video monitoring system(1.2m), and then, distribution density of snow crab in each observations were estimated as a counted number of crab per 1,000m2. The result shows that their survey, taken between two months, reflected similar results during survey period, and the maximum and mean distribution densities in September estimated to be 77.0(number/1,000m2) and 19.9, respectively, and those of October were 36.0 and 21.8, respectively.

본 연구에서는 원전 주제어실의 층 지진격리시스템에 대한 지진동 저감성능과 적용성을 평가하기 위해서 실험연구를 수행하였다. 층 지진격리시스템에 적용하기 위해서 납-고무 베어링(LRB)과 마찰진자장치(FPS)를 설계하고 제작하였다. 제어 캐비닛과 액세스 플로어로 구성된 원전 주제어실 부분 실험모형을 제작하여 납-고무 베어링과 마찰진자장치를 각각 설치하여 진동대 실험을 수행하여 지진응답특성을 비교, 평가하였다. 실험을 위해서 원전 주제어실의 운전기준지진(OBE)과 안전정지지진(SSE)의 수평방향 층응답 스펙트럼을 이용하여 인공지진 시간이력을 만들어서 진동대 실험에 사용하였다. 입력지진에 대한 실험모형의 지진응답은 마찰진자장치를 적용한 경우 상대적으로 우수한 지진동 저감특성을 나타냈다.

본 연구의 목적은 충남 오서산지역 소나무림을 대상으로 전반적인 수고생장 패턴과 지위지수식을 추정하고자 한다. 조사대상 지역은 충남 보령시와 청양군 일대의 소나무림을 대상으로 총 7개소의 조사지를 선정하여 매목조사를 실시하였으며, 이 중에서 총 21본의 표본목을 벌도하여 원판을 채취하였다. 채취한 원판들은 1/100mm의 정밀도를 가진 정밀연륜분석기(Model : DTRS-2000)를 사용하여 1년 단위의 수고, 직경, 재적 등의 생장량을 계산하였다. 본 연구에서는 총 181개의 수고-수령 관측치를 사용하여 Schnute의 생장함수식에 적용하였고 일반적인 수고생장의 패턴을 추정하였으며, 또한 이를 이용하여 기준임령을 30년으로 한 동형의 지위지수 추정식을 유도하였다. 본 연구에서 제시된 수고 및 지위지수 추정식은 충남지역에서 소나무림이 가장 많이 분포하고 있는 오서산지역 소나무림의 생장을 파악하는데 중요한 정보를 제시해 줄 것으로 사료된다.

The pressureless sintering behavior of /Cu powder mixtures, prepared from /CuO and /Cu-nitrate, has been investigated. Microstructural observation revealed that powders with nano-sized Cu particles could be synthesized by hydrogen reduction method. The specimens, pressureless-sintered at for 4 min using infrared heating furnace with the heating rate of /min, showed the relative density of above 90%. Maximum hardness of 16.1 GPa was obtained in /MgO/Cu nanocomposites. The nanocomposites exhibited the enhanced fracture toughness of 4.3-5.7 , compared with monolithic . The mechanical properties were discussed in terms of microstructural characteristics

Kimchi and soup/stew samples were collected from Korean restaurants in the Jeonju area and their salinity levels were analysed. Restaurant owners were also surveyed to assess their salt acceptability and attitudes. The average salinity of the Kimchi samples was 2.0±0.4% and that of the soup/stew samples was 1.0±0.3%. The average salinity of the soup samples was 0.9±0.2% and that of the stew samples was 1.1±0.3%, and the average salinity of the stews was significantly higher than that of the soups (p〈0.001). The average salinity of bean-paste soups was 0.9±0.2% and that of clear soups was 0.8±0.2%, in which the average salinity of the bean-paste soups was significantly higher than that of the clear soups (p〈0.05). When asked about the saltiness of their side dishes, soups/stews, and Kimchi, the largest number of owners answered 'ordinary'. About 50.4% of the owners also answered 'ordinary' for their salt acceptability, and 59.8% answered that their customers have 'ordinary' salt acceptability. However, a significantly higher ratio of owners in the group whose Kimchi samples had low salinity answered that their customers' salt acceptability was for 'flat' foods as compared to the group whose Kimchi was of high salinity (p〈0.05). About 45.7% of the owners answered that 'they participated in controlling the saltiness of all their dishes', and 40.2% answered that 'they considered the traditional saltiness of their menu items as more important than the saltiness acceptability of their customers.' Also, 82.7% of the owners answered 'they made the Kimchi themselves.' The types of frequently served soup were clear soup, such as bean-sprout soup and seaweed soup, followed by bean-paste soup and thick beef soup, in order. The types of frequently served stews were Gochujang stew with frozen pollack or croaker, bean-paste stew, and clear stew.

외부환경 변화와 천이의 영향으로 쇠퇴현상이 나타나고 있는 서울시 소나무림의 식생환경을 개선하고자 교목층 우점종의 경쟁관계, 하층식생내 경쟁종 출현 유무, 관리정도 등에 근거하여 유형을 구분하고 생태적 관리방안을 제안하였다. 서울시 소나무림을 생태적 특성에 따라 분류하면 소나무순림에 속하는 토지극상림(26.1%)과 소나무순림(21.5%), 소나무와 타 수종이 경쟁하는 소나무-신갈나무림(28.0%), 소나무-리기다소나무림(13.1%), 소나무-상수리나무림(4.2%)등으로 구분되었다. 이들 유형에 대한 정밀한 식생조사 결과, 토지극상, 답압피해, 식생관리로 인해 교목층과 하층에 경쟁종이 출현하지 않아 소나무림 유지가 가능한 4개 군집은 하층식생 보완 등 소극적인 관리가 필요하였다. 반면 교목층과 하층에 소나무와 경쟁수종인 낙엽성 참나무류와 외래종이 출현하는 4개 군집은 생태적 지위가 동일한 경쟁종관리, 하층식생 도입 등 적극적인 관리기법을 적용해야 소나무군집을 유지할 수 있을 것이다.

Temperature effects on diapause termination of Paratlanticus ussuriensis eggs were studied by measuring embryonic development and hatching rates at various conditions of indoor chilling and overwintering temperatures. Diapausing eggs of P. ussuriensis did not hatch at continued incubation at 25℃ and even after chilling for once at either 5℃ or 10℃ for 30, 45 and 60 days. In addition, double chillings at 5℃ with a 90 days interval at 25℃ did not induce hatching of diapausing eggs. However, double chillings at 10℃ induced hatching at 3.6~26.7%. When eggs were incubated at 25℃ after chilling for once at 5℃ for various periods, those weights were not changed but those chilled at 10℃ gradually increased to approximately 1.5 times. When 60-days-old eggs were artificially deposited under the soil at three different mountain sites in September 2007, the hatching rates of the first-overwintered eggs were 11.3, 3.5 and 4.1% and those of the second-overwintered eggs were 25.1, 21.6 and 0.4% at Hoepori, Bitanri and Hwasanri, respectively. Most eggs were hatched from mid-March to mid-April but little bit earlier in southern regions. During the hatching period soil temperatures in three tested locations were around 8 to 12℃. In overall, diapausing eggs of P. ussuriensis were greatly influenced by chilling temperature conditions and those repeated cycles, and may required overwintering for one or two times to hatch for the post-embryonic development.

A survey of total aflatoxin levels was conducted on 145 samples(carthamiflos, thujae semen, giycyrrhizae radix et rhizoma) collected in Yakyeang markets in Seoul. Aflatoxin levels were quantified by the immunoaffinity column clean-up method followed by performance liguid chromatography(HPLC)-fluorescence detector(FLD). Aflatoxins were found in 10(6.9%)samples including 5 Arecae semen, 4 Thujae semen, 1 Zizyphi semen with a range of 0.45~79.15 μg/kg. Generally These results show that the contamination level of aflatoxins in Herb Medicines consumed in Korea is high compared with the standard in Korea Herb Medicine Code(10 μg/kg as aflatoxin B1). It is considered that aflatoxin concentration was increased in herb medicines during a storage and drying in herb medicines examined