• Journal of Plant Biology
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• v.37 no.1
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• pp.53-67
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• 1994

The opal phytolith types in Oryza sativa L. were examined with light and scanning electron microscope, and we suggested the standard tenninoligies based on original cells of the phytoliths in situ. The distinctive fonus of opal phytoliths were observed in all plant parts such as leaf blade, leaf sheath, culm, root, glume, lemma, and palea. The phytolith fonus originated from long cell, short cell, and dennal appendages were different from part to part. The opal phytoliths derived from the long cells showed the most various form: twelve types were identified based on side wall shape. The results showed that the leaf blade did include almost all types of opal phytolith observed in the other parts of rice.f rice.

• Korean Journal of Plant Taxonomy
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• v.35 no.4
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• pp.313-335
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• 2005

Many plants take up soluble silica from the soil, and they deposit in plant tissues. Silica bodies are most commonly found in the leaf epidermis. Silica body is important factor in growth and development of plant. It help to maintain rigidity in stem and linear leaves, and its content may be correlated with resistance to fungal disease. In this study, several morphologically distinctive forms of silica bodies on Cyperaceae in Korea are recognized, which are eventually classified into two groups. Silica body type of first group (Rhynchospora, Fuirena, Scleria, Carex, Eriophorum) is A-type, which is conical in shape. Silica body type of second group (Cyperus, Scirpus, Eleocharis, Fimbristylis, Kyllinga, Bulbostylis, Lipocarpha) is B-type, which is conical in shape with numerous satellite body. These types are consistent enough to use as characters in taxonomic studies within genus. Silica body type may be associated with habitat: the species in dry region have A-type, whereas the species in wet region have B-type. These results suggested that shapes and presence or absence of silica body might be valuable to systematic analysis.

• 한국신재생에너지학회:학술대회논문집
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• 2005.11a
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• pp.446-461
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• 2005

본 연구에서는 반응소결 탄화규소 다공질 지지체 개발을 위하여 SiC/C로 이루어진 성형체를 사용한 Si melt infiltration 공정 및 SiC/C/Si으로 이루어진 성형체를 사용하는 Si embedding 공정 개발이 이루어졌다. 개발된 반응소결 탄화규소 다공질 지지체의 기공률은 38% 이상이었으며 평균기공은 130 ${\mu}m$ 크기이었다. Si melt infiltration 방법으로 제조된 반응소결 탄화규소 다공질 지지체의 파괴강도는 상용 반응소결 탄화규소 지지체의 파괴강도보다 최대 200% 이상 높게 나타났다. 본 연구에서는 용융 Si의 침윤공정을 이용하여 반응소결 탄화규소 여과층을 갖는 반응소결 탄화규소 필터 및 그 제조공정이 개발되었다. 개발된 반응소결 탄화규소 필터의 필터 특성은 상용 탄화규소 필터의 필터 특성과 대체적으로 대등한 것으로 조사되었다.

• Korean Journal of Plant Taxonomy
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• v.39 no.3
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• pp.199-215
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• 2009

Phytoliths formed on the leaf-blades of the seventeen Oryza species were examined using back-scattered electron imaging. The resulting descriptions of the phytoliths became the basis for a new key to the species of the genus. This key includes features useful for specific identification related to the silica bodies originating from epidermal cells upon both the mid-vein and bulliform cell, as well as of phytoliths originating from papillae, prickle hairs, large and small trichomes, and stomatal apparatus. These detailed phytolith descriptions, back-scattered electron images, and keys to both adaxial and abaxial sides of leaves, can now be used in identifying phytoliths from archaeological samples as well as extant species of Oryza.

• Journal of Plant Biology
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• v.35 no.3
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• pp.283-305
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• 1992

Phytoliths (plant stones) mean all types of mineral deposition formed in or between plant cells. However, most of the researches on the phytoliths so far have been focused on the opaline silica bodies (silicified phytoliths) formed by grasses. Therefore, the phytolith is usually refered to opaline silica body in a narrow sense. Phytoliths are very useful in grass classification, and their usefulness as microfossils is also proved in several other fields, including soil science, paleoecology, and archaeology. Recently attention has been paid to the possibility that they might function as carcinogen. The purpose of this review is to present an overview of the nature and analysis of phytoliths and their applications in botany as well as other fields of sciencess.encess.

• Journal of The Geomorphological Association of Korea
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• v.17 no.3
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• pp.1-16
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• 2010

Phytoliths, silica microfossil that produced within and between cells and tissues of plants are especially yielded in Gramineae with many different forms and can attribute to the reconstruction of climatic and environmental changes and agriculture activity of the Quaternary. The phytoliths in soil can remain for long periods of time, because of strong resistance to physical and chemical weathering. The spatial range of study is too small due to deposition of phytoliths directly to the soil. There are difficulties of phytoliths identification because of multiplicity and redundancy, so far uniform and exact classification scheme has not been adopted. Therefore we attempted phytolith classification system applied to Korea. The paleoenvironmental reconstruction research using phytholith are applicated in many parts of studies. Also high-resolution paleoclimatic reconstruction expected to be possible using phytolith indices of Iph and Ic as well as climatic indicator of phytolith morphology.

• Journal of the Korean Ceramic Society
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• v.13 no.3
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• pp.55-62
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• 1976

순수한 닉켈과 금 박막을 (III)규소 단 결정위에 진공 증착시켰다. Ni/Au/Si나 Au/Ni/Si시료를 진공중에서 약 55$0^{\circ}C$로 가열하였을 때 육방정 혹은 변형된 육방정의 미소 결정들이 규소 기질위에 형성되었다. 이들 미소 결정들의 형성과정 및 조성은 X-선 회절법, scanning electron microscopy 및 scanning Auger microprobe 법을 사용하여 결정하였다. 이들 미소 결정은 NiSi2임이 확인되었다. Ni/Au/Si 시료에서는 Au-Si 공융점(37$0^{\circ}C$) 이상으로 온도가 증가됨에 따라 닉켈과 규소가 Au-Si 공융체 속으로 이동한 후 반응하여 NiSi2를 형성하였다. Au/Ni/Si 시료에 있어서의 Au-Si 공융체 형성은 닉켈 박막에 있는 바늘구멍형의 표면 결함과 관련 지을 수 있겠다. 금이 닉켈 박막의 grain boundary를 통하여 Ni/Si 계면으로 확산되어 그 계면을 습윤시킨 다음 Au-Si 공융체를 형성하였다. 이런 Au-Si 공용체는 닉켈과 규소 원자에 대한 높은 확산 매질로서 작용하여 NiSi2 형성을 촉진시켰다. 표면에 평행한 (III)규소면 위의 NiSi2 미소 결정은 유사한 육방정으로 나타났으며, 경사진 미소결정은 부등변 사변형과 유사하였다. Auger 스펙트럼 및 Ni, Au 및 Si에 대한 내층조성(indepth Composition Profiles)은 NiSi2 미소 결정이 Au-Si 공융체의 matrix에 미소 부분으로 나타났음을 보여주었다.

• Korean Journal of Plant Taxonomy
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• v.31 no.4
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• pp.321-341
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• 2001

Phytoliths of leaf blades of Oryza were studied by light and scanning electron microscopy in order to assign the diagnostic character and taxonomic key for the genus. Some phytoliths such as stomatal apparatus, long-cell and short-cell, existing at the same position on the abaxial side of leaf blade, were intensively investigated because of their various forms documented in a previous study. These characters have value either for testing infrageneric classification or for identifying taxa within the genus. Stomatal phytolith is formed by integration of several kinds of sources, such as the guard and subsidiary cell and the papillae. The stomatal phytolith, characterized by not only the absence and presence of phytolith originated by the papillae developed on the guard and subsidiary cell but also their pattern of arrangement, shows various morphologies, and these features have congruent with the infrageneric classification such as section and/or series. Long-cell phytolith is characterized by the absence/presence, arrangement and morphology of phytoliths originated by the papillae on the cell surface. These features may hardly have any systematic relevance within the genus, but contain some informations for identifying of species. All of short-cell phytoliths found are silica body. They form various shapes like cross, bilobate, saddlelike and trilobate, and these features are consistent with infrageneric classification such as section and/or series. Also, some characters, the absence/presence of band of short cell phytolith within costal strip, the absence/presence of saddlelike phytolith within intercostal strip and the number of band of short cell phytolith within costal strip are various according to taxa, but these features do not fall into infrageneric classification. Some taxonomic keys on the phytoliths of stomatal, long-cell and short-cell were developed by their features, and the agreement between these characters and infrageneric classifications was also discussed.

• Korean Journal of Heritage: History & Science
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• v.42 no.3
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• pp.48-65
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• 2009

In order to understand the local vegetation history and the origin of rice cultivation, a phytoliths analysis was performed with sediments collected from archaeological site at Ga-dong in Gijang, Busan. From the analysis with the sediments of three sampling sites, fan-shape phytoliths of Oryza sativa were detected: sediment 8 ~ sediment 29 of sampling site 1, sediment 6 ~ sediment 20 of sampling site 2 and sediment 7 ~ sediment 33 of sampling site 3. On the bottom layers or near the bottom layers from the three sampling sites, high densities of Arundinoideae and Andropogoneae were detected. It indicates that these layers were wet soil environment when they were sedimented. From near bottoms up to surfaces, the densities of Arundinoideae and Andropogoneae were abruptly decreased, while the density of Oryza sativa was sharply increased. With these results, it should be considered that the rice cultivation was started from the Bronze Age on this region.

• Korean Journal of Materials Research
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• v.5 no.4
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• pp.468-475
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• 1995

활성금속 브레이징 방법으로 스테인레스 스틸과 질화규소를 접합하여 기계적 특성 및 유한요소법을 사용하여 접합체에서 발생되는 잔류응력의 크기를 조사하였다. 고강도 접합체를 제조하기 위하여 연성금속인 Cu 및 Cu/Mo 적층체를 중간재로 사용하였으며, 중간재의 두께 및 구조에 따라 접합체에서 발생되는 잔류응력의 크기 및 분포가 접합강도에 미치는 영향에 관하여 조사하였다.중간재인 Cu의 두께가 0.2mm 일대 세라믹스에 발생되는 최대 잔류응력의 크기가 급격히 감소하였으며, 최대 접합강도가 나타났다. Cu/Mo 다층 중간재를 사용한 접합체에서는 Cu/Mo 두께비가 감소할수록 접합강도는 증가되었다. 스테인레스 스틸/질화규소 접합체에서 Cu/Mo 중간재의 사용은 Cu 중간재 사용보다 접합강도를 증가시키는데 효과적이었으며, 최대 접합강도는 450Mpa 정도이었다. Cu/Mo 중간재를 사용한 접합체에서는 Mo에 최대 인장방향의 잔류응력이 발생하여 강도 측정시 Mo의 지배적인 소성변형으로 잔류응력이 감소되어 접합체의 접합강도를 향상시키는 것으로 생각된다.