The overall process, from the pre-treatment of aluminum substrates to the eco-friendly neutral electroless Ni-P plating process, was observed, compared, and analysed. To remove the surface oxide layer on the aluminum substrate and aid Ni-P plating, a zincation process was carried out. After the second zincation treatment, it was confirmed that a mostly uniform Zn layer was formed and the surface oxide of aluminum was also removed. The Ni-P electroless plating films were formed on the secondary zincated aluminum substrate using electroless plating solutions of pH 4.5 and neutral pH 7.0, respectively, while changing the plating bath temperature. When a neutral pH7.0 electroless solution was used, the Ni-P plating layer was uniformly formed even at the plating bath temperature of 50 oC, and the plating speed was remarkably increased as the bath temperature was increased. On the other hand, when a pH 4.5 Ni-P electroless solution was used, a Ni-P plating film was not formed at a plating bath temperature of 50 oC, and the plating speed was very slow compared to pH 7.0, although plating speed increased with increasing bath temperature. In the P contents, the P concentration of the neutral pH 7.0 Ni-P electroless plating layer was reduced by ~ 42.3 % compared to pH 4.5. Structurally, all of the Ni-P electroless plating layers formed in the pH 4.5 solution and the neutral (pH 7.0) solution had an amorphous crystal structure, as a Ni-P compound, regardless of the plating bath temperature.

느타리 ‘흑타리’ 품종의 배양 중 고온스트레스에 의해 발생되는 미발이 현상을 구명하기 위하여 배양온도에 따른 생육차이를 조사하였다. PDA 배지에서‘흑타리’의 적정생육온도는 23~26 ̊C였고, 균사생장속도는 ‘춘추2호’에 비하여 빠른편이었다. 병내 배지온도는 초기에 상승하여 배양 중반에 최고점에 도달한 후 온도가 하강하였다. 배양 온도가 높을수록 배양기간은 짧아졌다. 배양온도 20 ̊C 처리구에서 배양기간은 25일 정도 소요되었으며, 미발이율은 1.8%, 수량은 139.4 g/병을 나타내었다. 배양온도 24 ̊C 처리구에서 배양기간은 20일 정도 소요되었으며, 미발이율은 4.2%, 병당수량은 132.1 g/병을 나타내었다. 배양온도 16 ̊C와 28 ̊C처리구에서는 미발이율이 증가되었고 수량이 감소하였다. 이 결과를 바탕으로 농가에서 배양온도와 미발이율의 관계를 조사하였다. 배양실 온도를 18 ̊C로 설정하고 배지품온을 28 ̊C 미만으로 관리하는 농가는 미발이율이 0.3~0.8%를 나타내었다. 배양실내의 온도가 20 ̊C 이상이며 환기가 잘 이루어지지 않은 농가에서는 미발이율이 3.5% 정도 발생되었다. 배양실 온도가 19 ̊C이며 배지 최고 품온이 31.3 ̊C까지 상승하는 농가는 미발이율이 8.2%로 높게 나타났다. 배양중 병내부 온도가 28 ̊C이상 상승하고 배양실내의 환기가 잘 이루어지지 않을 경우 미발이율이 증가하고 수량이 감소되는 경향을 보였다. 결과적으로, 배양실은 배지품온이 28 ̊C 이상 상승하지 않도록 배양실 내부의 공기를 지속적으로 순환시키고, 배양공간에 맞는 최적의 배양량을 넣어 관리하여야 한다.

As an approach for estimation of the droplet size in the molten salt-liquid metal extraction process, a droplet formation experiment at room temperature was conducted to evaluate the applicability of the Scheele-Meister model with water-mercury system as a surrogate that is similar to the molten salt-liquid metal system. In the experiment, droplets were formed through the nozzle and the droplet size was measured using a digital camera and image analysis software. As nozzles, commercially available needles with inner diameters (ID) of 0.018 cm and 0.025 cm and self-fabricated nozzles with 3-holes (ID: 0.0135 cm), 4-holes (ID: 0.0135 cm), and 2-holes (ID: 0.0148 cm) were used. The mercury penetration lengths in the nozzles were 1.3 cm for the needles and 0.5 cm for the self-fabricated nozzles. The droplets formed from each nozzle maintained stable spherical shape up to 20 cm below the nozzle. The droplet size measurements were within a 10% error range when compared to the Scheele-Meister model estimates. The experimental results show th

The study was conducted to investigate the effects of post-incubation period and temperature treatment conditionsduring incubation on the uniform primordia formation and cultural characteristics of oyster mushroom (Pleurotus ostreatus). Threekinds post-incubation period; 25, 30, 35 days and control were applied for 30 days while two kinds incubation roomtemperature 23oC and 26oC and control were used 20oC. The substrate temperature during pre-incubation was of ‘Suhan No. 1’and ‘Gonji No. 7’. Oyster mushroom varieties tended to increase between 24oC to 26oC at 11 to 15 days after inoculation andthen they were maintained in treatment temperature during post -incubation period. The CO2 occurrence was at the highest at6,500ppm for ‘Suhan No. 1’ and 5,800ppm for ‘Gonji No. 7’ at the time of the highest temperature increase. The ratio of un-uniformal primordia formation and the ratio of non-commercial fruit body were reduced by 40%, 10.5%, respectively comparedto control for ‘Suhan No. 1’ when in the post-incubation temperature was 26oC, and incubated for 10days and 15daystreatment. Also, ‘Gonji No. 7’ was reduced by 19%, 9.5%, respectively when in the post-incubation temperature was 26oC, andincubated for 10 days treatment. Therefore, the higher post-incubation temperature of room and longer post-incubation periodresulted in the higher percentage of primordia formation of two cultivars.

Fe-aluminides have the potential to replace many types of stainless steels that are currently used in structural applications. Once commercialized, it is expected that they will be twice as strong as stainless steels with higher corrosion resistance at high temperatures, while their average production cost will be approximately 10% of that of stainless steels. Self-propagating, high-temperature Synthesis (SHS) has been used to produce intermetallic and ceramic compounds from reactions between elemental constituents. The driving force for the SHS is the high thermodynamic stability during the formation of the intermetallic compound. Therefore, the advantages of the SHS method include a higher purity of the products, low energy requirements and the relative simplicity of the process. In this work, a Fe-aluminide intermetallic compound was formed from high-purity elemental Fe and Al foils via a SHS reaction in a hot press. The formation of iron aluminides at the interface between the Fe and Al foil was observed to be controlled by the temperature, pressure and heating rate. Particularly, the heating rate plays the most important role in the formation of the intermetallic compound during the SHS reaction. According to a DSC analysis, a SHS reaction appeared at two different temperatures below and above the metaling point of Al. It was also observed that the SHS reaction temperatures increased as the heating rate increased. A fully dense, well-bonded intermetallic composite sheet with a thickness of 700 μm was formed by a heat treatment at 665˚C for 15 hours after a SHS reaction of alternatively layered 10 Fe and 9 Al foils. The phases and microstructures of the intermetallic composite sheets were confirmed by EPMA and XRD analyses.

A long-term in situ observation was carried out in the Ice-valley at Milyang in order to explain the factors and processes associated with the summertime ice formation. The variation of temperature inside Ice-valley in relation with ice formation in summer time was found to depend on precipitation rate in spring and cold air sinking in autumn and winter. The rate of temperature rising tends to correspond to sensible heat release depending on the precipitation amount at the freezing location. The reason of the cold air accumulation in a talus in the Ice-valley is the cold air sinking over the surface of talus due to the occurrence of outside clod air mass and the accumulated cold air from autumn to spring flow outside at the bottom of talus. The out-flowing cold air can result in the ice formation in the hot summer.

발전소 내 방사화 부식생성물의 대부분을 차지하고 있는 니켈 페라이트계 부식생성물을 모사 발생시키기 위한 고온 고압용 장치를 제작하여 연구를 수행하였다. 배관형 포집기를 이용한 부식생성물 발생장치로부터 방사화 부식생성물과 가장 유사한 부식생성물을 얻을 수 있었다. 발전소에서 입자성 부식생성물이 발생되는 원리인 온도에 따른 용해도 차이를 구현하기 위하여 270C에서 부식반응이 일어나 상대적으로 높은 온도를 가진 포집용 장치에 부식생성물이 포집되도록 장치를 제작하였으며 , 발생된 부식생성물은 주사전자현미경 관찰과 EDAX를 통한 조성분석으로 그 특성을 관찰하였다. 부식생성물은 포집 된 위치 에 따라서 침상 형태의 산화물과 결정 형태의 산화물로 나뉘었으며, 조성 분석 결과 결정 형태의 부식생성물이 니켈 페라이트로서 발전소에서 발생되는 입자성 부식생성물과 유사한 것을 알 수 있었다.

Al-Cr-Zr metal powders were prepared by cryo-milling(-75),ambi-milling(25) and warm-milling(200) to investige the effect of milling temperature. The morphogical changes and microstructural evolution of Al-6wt.%Cr-3wt.%Zr metal powder ball milling were investigated by SEM, OM and XRD. The cryo-milling at -75 caused the more refinement of powder particle size than ambi-milling and warm-milling. The partic morpholgy of Al-Cr-Zr metal powders changed changes into spheroidal particles at 25and spherical particles at 200The spherical particles were formed by agglomertion and contiuous wrapping of the spheroidal particles. The calculated Al crystallite size in Al-Cr-Zr metal powders by the Scherer equation were refined rapidly for short milling time -75compared with milling at 25 and 200.

The effect of ripening temperature, pH and salinity on the formation of N-nitrosamine (NA) during Kimchi fermentation and in vitro was studied, respectively. During Kimchi fermentation for six weeks at cold storage temperature (4℃) and room temperature (16 ±2℃), the contents of nitrite and dimethylamine (DMA) showed variation at room temperature but no variation at cold storage temperature. The maximum generation of nitrosodimethylamine (NDMA) resulted low content (2.69 ug/kg) at cold storage temperature but started to increase after one week fermentation and reached to the 18-fold higher generation (49.6 ug/kg) at room temperature. During Kimchi fermentation, no correlation was observed between the variation of nitrite and DMA content and the generation of NDMA. However, pH showed effective relation to NDMA generation such as the highest NDMA generation was obtained at lowest pH 4. During in vitro test, higher temperature and lower pH resulted more NDMA generation and generation amount was affected more by pH. Also, the salinity of Kimchi provided inhibitory effects on the formation of NDMA. NDMA was produced 5.86 ug/kg at normal salinity (2.5%) but 90.9 ug/kg at lower salinity (15%) after three week. The higher salinity showed lower formation of NDMA in vitro test, too.

광 및 온도가 꼬마배나무이의 겨울형성충(월동형) 발생에 미치는 영향을 조사한 결과 수원지역(북위 16') 의 꼬마배나무이 개체군은 광길이가 14시간일 때 부터 겨울형성충이 출현하였으며 광길이가 13시간일 때 9 93% 이상의 겨울형성충이 발생하였다. 또한 , 의 두 온도조건에서 겨울형성충 발생에 차이가 없었다. 꼬마배나무이의 각 발육단계별로 단일조건에 처리한 결과 1,2령기에 처리된 것은 각각 67.2, 54.4%가 겨 울형으로 되었고, 3령기는 9.3% 였으며 4령기부터는 영향을 받지 않았다. 꼬마배나무이의 평균산란수는 겨울형성충이 486.4개, 여름형성충이 387.2개 이었으며, 산란기간은 각각 34일과 24일 이었다.

In this study, an attempt was made to fabricate TiAl as well as its in situ composite via combustion synthesis. The processing variable of the combustion synthesis which include aluminum content and the heating rate were found to affect the combustion temperature. The combustion temperature measured, however, was lower than the melting temperature of TiAl and the reaction product were found to include incomplet reaction products. Carbon was added in order to increase the combustion temperature as well as to form in situ reinforcements. The reaction products showed homogeneous microstructures with carbide phases formed within indicating that the addition of carbon increased the combustion temperature above the melting temperature of TiAl.

본 연구에서는 동일한 농도의 유동파라핀/ Span 80-Tween 80/ 정제수로 구성되는 조성물을 혼합 경 로와 온도에 따라 형성되는 에멀젼 상태를 비교하였다. 3성분계도상에서 최종 조성에 이르는 혼합경로는 세 가 지로 구성하였다. 혼합 경로에 따라서 제조된 에멀젼의 평균 입자크기는 큰 차이를 보였으며 제조 온도가 증가함 에 따라서도 에멀젼의 입자크기가 감소하였다. 그러나 혼합 온도보다는 혼합 경로에 따른 영향이 더욱 컸다.