A molten salt reactor (MSR) has considerably attracted attention due to its several advantages for the safety and efficiency over the light water reactors. Because the structural material in MSR is contacted with high-temperature liquid fuel during long-term, the excellent material for corrosion resistance is required to be applied in MSR. In this study, we evaluated the corrosion resistance for alloy 600 and 617, which are the nickel-based materials, in KCl molten salt at 800ºC for 100 h under Ar atmosphere containing less than 1 ppm of moisture and oxygen. After the corrosion experiments of alloy 600 and 617, the amount of the weight loss for them caused by the KCl molten salt were determined. In addition, the variation in the crystal structure, surface morphology, and elemental distribution was examined using X-ray diffraction and scanning electron microscopy equipped with energy dispersive X-ray spectroscopy.

Cordyceps militaris is a entomopathogenic ascomycetous fungus and cultivated as a medicinal mushroom having many valuable biological and pharmaceutical activities. It was cultivated on five different grain media which were compared with silkworm pupa medium for the artificial fruiting body production. C/N ratio of pupa and bean media was low at 5.9 and 5.8 respectively, which was attribute to low nitrogen contents compared to others. The various media had a significant effect on mycelial growth, cordycepin contents, fruiting body production. The mycelial growth were greatest at barley and wheat media but least at pupa medium. The cordycepin contents were highest at bean and pupa media with 2.9 and 2.6 mg/g, respectively. This was followed by wheat, corn, barley and brown rice media. The yield of fruiting body was greatest at barley and wheat media but the yield and days to harvest were least at silkworm pupa medium.

The Monokaryotic isolates of two strains collected from two different strains 'SH' and 'MS of P. ostreatus were used to estimate the compatibility of matings. They were crossed in all combinations and dikaryon formation was assayed by the presence of clamp connections. All 134 dikaryotic F1 hybrids were obtained out of 144 monokaryotic crosses derived from two parent strains. The growth and density of the F1 hybrid mycelia differed considerably and the morphological characteristics of mycelial colony of F1 hybrids varied from cottony, feathery, puffy to streak. When the 12 monokaryons of 'SH' crossed with 12 monokaryons of 'MS', 122 strains were capable of normal fruiting and 12 were not fruited among 134 strains tested indicating 91% success rate. The reason for failure of fruiting body formation in 12 combinations may be not because of the incompatibility of mating types but unfavorable environmental condition for fruiting initiation and development. The pileus of F1 hybrids were varied with funnel 68.0%, hemispherical 25.4%, plane 6.6% in the shape and gray 59.8%, blue 35.3%, white 3.3%, brown 1.6% in the color.

Maintaining and preserving mushroom mycelial cultures for ensuring the genetic, morphological, physiological traits and viability over time are essential elements in mushroom production. A number of different mushroom species can be preserved by many means, such as cryopreservation, freeze-drying, and placement in preservation solutions like mineral oil, distilled water, or glycerol. This study tested simple and low-cost preservation methods of the mushroom strains from various species, namely Pleurotus ostreatus, Agaricus bisporus, Cordyceps militaris. Each mycelium was cultured and preserved in different storage temperatures and methods. Temperature were differed at 4, 14, 24, 34°C at agar slants. Different storage methods were cryobial tube with sterile water, cryobial tube + 10% glycerol, agar slant of test tube, and agar slant + mineral oil at 4°C for 2 years. The mushroom cultures were better in the viability and recovery at 4°C than those of preservation at higher temperatures. Result showed that all the mushroom strains tested remained viable without any contamination under all different storage methods over two year duration of the experiment. However, all the strains studied could be best stored in sterile water with 10% glycerol for the viability.

The effects of environmental and nutritional requirement such as temperature, pH, different media, carbon, nitrogen, and carbon-to-nitrogen ratio on the mycelial growth of Cordyceps militaris strain ‘Yedang 3’ were studied. The optimum temperature and pH for the growth of mycelium were 20-25oC and pH 6-7, respectively. Out of ten media tested, mushroom complete media (MCM) was the best medium for fast mycelial growth, and Sabouraud’s dextrose agar yeast extract (SDAY), malt extract yeast extract agar (YMA) also were favored. The color and shape of colonies varied in different media. The best carbon sources for mycelial growth were fructose, mannitol, and sucrose, whereas the best nitrogen sources were tryptone and peptone. However, mycelia grew slowly in inorganic nitrogen compounds such as NH4Cl, (NH4)2SO4, NH4NO3, and NaNO3. The optimum C:N ratio observed on the culture media was 30-40 range. These results provided basic information on cultural characteristics of vegetative growth and might be useful for spawn production in Cordyceps militaris.

Two different schemes were adopted to fabricate ordered macroporous structures with face centered cubic lattice of air spheres. Monodisperse polymeric latex suspension, which was synthesized by emulsifier-free emulsion polymerization, was mixed with metal oxide ceramic nanoparticles, followed by evaporation-induced self-assembly of the mixed hetero-colloidal particles. After calcination, inverse opal was generated during burning out the organic nanospheres. Inverse opals made of silica or iron oxide were fabricated according to this procedure. Other approach, which utilizes ceramic precursors instead of nanoparticles was adopted successfully to prepare ordered macroporous structure of titania with skeleton structures as well as lithium niobate inverted structures. Similarly, two different schemes were utilized to obtain disordered macroporous structures with random arrays of macropores. Disordered macroporous structure made of indium tin oxide (ITO) was obtained by fabricating colloidal glass of polystyrene microspheres with low monodispersity and subsequent infiltration of the ITO nanoparticles followed by heat treatment at high temperature for burning out the organic microspheres. Similar random structure of titania was also fabricated by mixing polystyrene building block particles with titania nanoparticles having large particle size followed by the calcinations of the samples.

Aqueous gold nanoparticle dispersion was synthesized by chemical reduction method using diethanolamine as reducing agent and polyethyleneimine as dispersion stabilizer. The synthesis conditions for the stable dispersion of the gold nanoparticle suspension were determined by changing the amount of the reducing agent and dispersant during the wet chemical synthesis procedures. The face centered cubic lattice structure of the gold nanoparticles was confirmed by using X-ray diffraction and the morphologies of the nanoparticles were observed by transmission electron microscope. The synthesized gold nanoparticle dispersion was concentrated by evaporating the dispersion medium at room temperature followed by the addition of ethyleneglycol as humectant for the increase of the elastic properties to obtain gold nanoparticle inks for direct ink writing process. The line patterns were obtained with the gold nanoparticle inks during the writing procedures and the morphologies of the fine patterns were observed by scanning electron microscope.

기존의 번데기동충하초의 자실체 생산은 자연계에서 채집된 버섯의 조직을 분리하거나 다중의 포자를 이용하는 방법이 대표적이었으나 본 연구를 수행한 결과, 단포자를 선발한 후 교배조합에 의한 F1균주를 이용한 배양이 안정적임을 확인 할 수 있었다. 단포자의 특성으로는 자실체의 형성이 양호하며 균주의 안정성이 우수한 균주를 선발하고 조합형성능이 우수한 균주를 선발하여야 한다. 본 연구를 통하여 06S05의 단포자를 획득하였으며 06S05x06S01, 06S05x06S33균주를 선발하였으며 06S05x06S33균주를 예당 3호로 명명하여 국립종자원에 품종보호 등록되었다.