• Journal of the Korean Wood Science and Technology
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• 제15권3호
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• pp.1-13
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• 1987

This study was carried out to investigate the variations of dimension and exterior shape of vessel elements, morphology of spiral thickening and ray-vessel pit in korean diffuse-porous woods (56 species, 18 families), The tangential pore diameter and vessel element length was increased, whereas the pore number per unit area($1mm^2$) was decreased from pith outwards. The tangential pore diameter was decreased but the length of vessel element was not changed from earlywood to latewood within an annual ring. However, the dimensional variations of vessel element was not able to be recognized among relative positions in peripheral variation. The exterior shape of vessel element could be classified into four types; Type 1 is without tail, Type 2 with ligulate tail, Type 3 with broad taper tail and Type 4 with the very short length between perforations. The distribution frequency of Type 2 and 3 was relatively high in comparision with the others. According to the prominence, distribution position and branched shape, the spiral thickenings could be divided into five types. The spiral thickenings occurred 52% in the species observed. Thus it was doubtful to consider the simple presence of spiral thickening as diagnostic index in diffuse-porous woods. The morphology of ray-vessel pit could be grouped as reticulate, scalariform, oval, linear and coalescent type. Most of species examined showed oval and linear type.

• 한국세라믹학회지
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• 제41권7호
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• pp.493-496
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• 2004

The chemical etching of sapphire substrates was peformed to produce smooth surfaces on an atomic scale. The sapphire sur-face etched by using a $H_2$S $O_4$ solution showed a pit-free morphology and was yen smooth as much as $\sigma$$_{rms}$=0.13 nm, that etched by using a mixture of $H_2$S $O_4$ and $H_3$P $O_4$ contained large pits with $\sigma$$_{rms}$=0.34 nm. The $\sigma$$_{rms}$’s and the number of the pits increased with increasing etching temperature. The sapphire etched by using $H_2$S $O_4$ at 32$0^{\circ}C$ had the best surface. These results provide important information on the effects of etching treatment on the structural properties of sapphire for the growth of high-quality epilayers.ayers.

• 대한치과기공학회지
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• 제36권3호
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• pp.205-217
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• 2014

Purpose: This study will examine the differences among the college dental morphology textbooks in light of their contents and learning objectives through which we will propose an optimal way of consolidating those differences found. Methods: Five college textbooks adopted in the dental related departments were selected by random and the overview and subdivisions of contents were compared and closely analysed with regards to the learning objectives. Results: Firstly, all of the dental morphology textbooks cover the learning objectives of the dental morphology subject, especially in the area of the overview of dental morphology, the permanent tooth, deciduous tooth. Only the dentistry textbooks explain the learning objective of the occlusion. Secondly, differences in content were found in the area of component tissue and around tissue, dental formula of deciduous teeth, spinous process, buccal pit, enamel projection, curve symbol, tip of cusp position of proximal surface of permanent mandibular canines, buccal cusp position of permanent mandibular second premolars. Conclusion: It is imperative to delineate some meaningful and critical differences in contents among the dental morphology textbooks and reflect this to each and every textbook to be published as a supplementary information guide or index.

• Corrosion Science and Technology
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• 제14권4호
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• pp.184-189
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• 2015

In this study, the combined effect of chloride and thiosulfate ions and the effect of the ratio of the two ions on passivation in 304L, 316L, and the duplex stainless steels 2101 and 2205 are investigated using potentiostatic scratch tests. Cyclic polarization and the scratch tests were used to understand the role of anions on localized corrosion in these systems. It was found that the thiosulfate pitting began at a lower potential for 2101 than 304L in 0.6 M NaCl + 0.03 M $Na_2S_2O_3$ solution. The pit morphologies for 304L, 316L, and 2101 in an 0.6 M NaCl + 0.03 M $Na_2S_2O_3$ solution were very different from each other. The results indicate that the pitting switches from predominately thiosulfate pitting to chloride pitting at approximately 0.1 V.

• 대한기계학회논문집
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• 제3권3호
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• pp.116-123
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• 1979

On the basis of optical microscope and electro microscope observation for the fatigue fracture process of medium corbon martensitic structure produced by rapid heat treatment, mainly the abstracts of the studied results for the morphology of fatigue crack initiation process of high hardened steel are summarized as follows. Fatigue crack initiated from inclusion on the surface or subsurface. Above all the crack which initiated from inclusion exposed on the surface in as follows. (1) fatigue crack initiated from the boundary of the matrix and inclusion. (2) fatigue crack initiated at surrounding of small pit by drop out of inclusion.

• 한국전기전자재료학회논문지
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• 제24권10호
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• pp.779-783
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• 2011

The morphology of etch pits in commercial 4H-SiC epi-wafer were investigated by molten-KOH etching. The etching process was optimized in $525{\sim}570^{\circ}C$ at 2~10 min and the novel type of etch pits was revealed. This type of etch pits have been considered as TED (threading edge dislocation) II, its origin and nature, however, are not reported yet. In this work, the morphology and evolution of etch pits during epitaxial growth were analyzed and the different behavior between TED and TEDII was discussed.

• ALGAE
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• 제37권1호
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• pp.15-32
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• 2022

Inspecting herbaria collections of Laurencia rigida highlighted frequent misidentifications between L. rigida and L. heteroclada f. decussata, two poorly studied taxa from Australia. Recent collections of DNA material, including from topotype material, allowed for re-examination of these two taxa using molecular techniques. Detailed morphological and molecular analyses based on two markers (rbcL and COI-5P) strongly supported these two taxa as being distinct from each other and requiring nomenclatural changes. Comprehensive morphological analyses highlighted features useful for accurate identifications. Interestingly, L. rigida was found to belong to the genus Palisada with evidence from both the morphology and molecular data. Therefore, this study proposed recognizing L. rigida as Palisada rigida comb. nov. Molecular data for L. heteroclada f. decussata on the other hand supported its separation from L. heteroclada, with too great a molecular distance to be considered a variety. Morphological characters that best separated P. rigida from L. decussata included seven characters; number of pericentral cells per vegetative axial segment, the presence of secondary pit connections, the presence of lenticular thickenings, tetrasporangia alignment, the presence of corps en cerise, holdfast morphology, and overall plant shape. Morphologically, L. heteroclada f. decussata was also separated from L. heteroclada, particularly by the following characteristics; ultimate branchlets morphologies, lower order branch lengths, primary axis and holdfast morphologies. Therefore, it was proposed that L. heteroclada f. decussata is recognized at a species level as L. decussata comb. et stat. nov.

• 반도체디스플레이기술학회지
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• 제2권2호
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• pp.5-8
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• 2003

In this study, as Cu diffusion barrier, tantalum nitrides were successfully deposited on Si(100) substrate and $SiO_2$ by plasma assisted atomic layer deposition(PAALD) and thermal ALD, using pentakis (ethylmethlyamino) tantalum (PEMAT) and NH$_3$ as precursors. The TaN films were deposited at $250^{\circ}C$ by both method. The growth rates of TaN films were 0.8${\AA}$/cycle for PAALD and 0.75${\AA}$/cycle for thermal ALD. TaN films by PAALD showed good surface morphology and excellent step coverage for the trench with an aspect ratio of h/w -1.8:0.12 mm but TaN films by thermal ALD showed bad step coverage for the same trench. The density for PAALD TaN was 11g/cmand one for thermal ALD TaN was 8.3g/$cm^3$. TaN films had 3 atomic % carbon impurity and 4 atomic % oxygen impurity for PAALD and 12 atomic % carbon impurity and 9 atomic % oxygen impurity for thermal ALD. The barrier failure for Cu(200 nm)/TaN(10 nm)/$SiO_2$(85 nm)/ Si structure was shown at temperature above $700^{\circ}C$ by XRD, Cu etch pit analysis.

• Steel and Composite Structures
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• 제50권3호
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• pp.363-374
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• 2024

The fatigue life of steel wire is affected not only by fatigue load, but also by corrosion environment in service period. Specially, the corrosion pit will lead to stress concentration on the surface of steel wire inducing the formation of fatigue cracks, and the fatigue cracks will accelerate the corrosion process. Therefore, the corrosion fatigue of steel wire is a coupling effect. In this study, the corrosion-fatigue coupling life curve is derived with considering corrosion-fatigue pitting stage, corrosion-fatigue short crack stage and corrosion-fatigue long crack stage. In addition, the stress concentration factors of different corrosion pits are calculated by COMSOL software. Furthermore, the effect of corrosion environment factors, that is, corrosion rate, corrosion pit morphology, frequency and action factor of fatigue load, on fatigue life of steel wire is analyzed. And then, the corrosion-fatigue coupling life curve is compared with the fatigue life curve and fatigue life curve with pre-corrosion. The result showed that the anti-fatigue performance of the steel wire with considering corrosion-fatigue coupling is 68.08% and 41.79% lower than fatigue life curve and fatigue life curve with pre-corrosion. Therefore, the corrosion-fatigue coupling effect should be considered in the design of steel wire.

• 암석학회지
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• 제20권3호
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• pp.151-159
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• 2011

제주시 봉개동의 고냉이술 일대의 지질은 오래된 것으로부터 영평동현무암, 신안동현무암, 봉개동현무암 및 분석층으로 구성된다. 영평동현무암과 신안동현무암은 고냉이술 오름의 남쪽 중산간 지역에 위치하고, 고냉이술 오름과 그 북부 저지대 일원에는 봉개동현무암이 분포한다. 봉개동현무암은 아아 용암으로 주로 구성되며, 용암 켜 사이에 두터운 클링커를 협재하고 있다. 고냉이술 오름은 화산지형학적으로 하나의 독립된 소화산으로 만들어져 있으며, 고냉이술 오름의 산정부에는 낮은 외륜산릉으로 둘러싸여 있는 넓은 분화구를 가지고, 그 내부에는 분지형 함물지인 여러 개의 피트 분화구(pit carter)를 가지는 용암순상화산이다. 고냉이술 오름의 저면 고도는 295 m에서 300 m (평균 297.5 m)이며, 최고봉의 고도는 304.5 m, 저면의 지름은 평균 597.5 m, 비고는 7.9 m로 사면경사각은 $1.5^{\circ}$이다.