• Korean Journal of Plant Taxonomy
• /
• v.42 no.2
• /
• pp.141-149
• /
• 2012

To clarify some ambiguous diagnostic characters of Callicarpa japonica Thunb. and Callicarpa dichotoma (Lour.) K. Koch in Korea (Verbenaceae), the external morphology and micromorphology (leaf, anther, pollen, fruit, in particular endocarp surface and structure) of two taxa are studied and described in detail. It is confirmed that the following characteristics (e.g., the stem outline in a cross-section, the bud shape and length, the corolla tube length and the lobe length, the pattern of the anther dehiscence and length, and the endocarp morphology) are useful for distinguishing these two taxa. In particular, following three characteristics are most useful for an identification: (1) the corolla tube length of C. japonica (2.5-4.6 mm) is longer than that of C. dichotoma (0.7-1.0 mm); (2) the anther is dehiscing by an apical pore at the anthesis of C. japonica, while it is opening by a long fissure from the apex to the base in C. dichotoma; and (3) the edge of the endocarp (lateral view) in C. japonica is concave, while in C. dichotoma it is shown to be flat. On the other hand, the teeth state on the leaf margin and the position of inflorescence are not good diagnostic characteristics for identification. Additionally, the keys for all known Callicarpa taxa in Korea are provided.

• Journal of Oral Medicine and Pain
• /
• v.36 no.3
• /
• pp.161-167
• /
• 2011

Sialolith is one of the most common pathologic conditions found in the salivary glands. The mechanisms responsible for the formation of sialoliths have not been elucidated so far. In this article, the chemical composition and micromorphology of a sialolith of a 58-year old female patient suffering from chronic sialoadenitis of the submandibular gland was analyzed using scanning electron microscopy (SEM) and energy-dispersive X-ray spectroscopy (EDX). In a SEM evaluation, the highly mineralized amorphous core surrounded by lamellar and concentric structures was revealed, however no foreign body, organic material, or signs of microorganism were observed in the core of the sialolith. EDX analysis showed the central core was composed of only Ca, O and P, and that a high level of C was detected near the central area as well. These results indicated that the inorganic composition of the sialolith was hydroxyapatite crystals, and that inorganic and organic substances existed around the central cores. This study suggests that the sialolith was composed mainly of hydroxyapatite crystals and the formation of the nucleus of the sialolith in the submandibular gland duct was secondary to sialadenitis, which favors the growth of an inorganic crystalline nucleus.

• KSCE Journal of Civil and Environmental Engineering Research
• /
• v.43 no.1
• /
• pp.21-32
• /
• 2023

Interrill erosion dominates in forest areas, and the erosion rate in surface-disturbed areas is significantly increased by the development and expansion of rill. In this study, soil erosion experiments using simulated rainfall and inflow were performed to understand the development and the micromorphological changes of rill on steep slopes. The characteristic factors of the micromorphology, such as the rill cross section, rill volume, rill density, rill order, and rill sharpness, were analyzed according to steepness and location (upper or lower) of slope. The head-cut of the simultaneous incised rills by rainfall simulation moved rapidly upslope, and the randomly developed rills expanded deeply and widely with their connection. The rill cross section evolved to downslope gradually increased. The rill volume occupied about 78 % of the sediment volume, confirming that the contribution of the sediment from the rill erosion is greater than that of the interrill erosion. Although the rate of increase in rill order slowed as the slope increased, the total length and density of the rill generally increased. As the slope increased from 15° to 20°, the bed incision of rills became larger than the sidewall expansion, and the rill sharpness increased by 1.6 times. The runoff coefficient on the lower slope decreased by 12.3 % than that on the upper slope. It was evaluated that the subsoil exposures and formation changes by the rill expansion increased the infiltration rate. Although the sediment accompanying the rills generally increased with slope increase, it was directly influenced by the hydraulic velocity of enhanced rill with the local convergence and expansion in the process of the rill evolution.

• Journal of the Korean institute of surface engineering
• /
• v.41 no.5
• /
• pp.199-204
• /
• 2008

Indium tin oxide (ITO) has been commonly used as an anode for organic light emitting diode (OLED), because of its relatively high work function, high transmittance, and low resistance. The ITO was mostly deposited by capacitive type DC or RF sputtering. In this study we introduced a new facing target sputtering method. On applying this new sputtering method, the effect of fundamental deposition parameters such as substrate heating and post etching were investigated in relation to the resultant I-V-L characteristics of OLED. Three kinds of ITOs deposited at room temperature, at $400^{\circ}C$ and at $400^{\circ}C$ with after surface modification by $O_2$ plasma etching were compared. The OLED on ITO deposited with substrate heating and followed by etching showed better I-V-L characteristics, which starts to emit light at 4 volts and has luminescence of $65\;cd/m^2$ at 9 volts. The better I-V-L characteristics were ascribed to the relevant surface roughness with uniform micro-extrusions and to the equi-axed micromorphology of ITO surface.

• Journal of radiological science and technology
• /
• v.31 no.1
• /
• pp.49-54
• /
• 2008

After x-ray 5Gy radiation on the whole body of a mouse using a linear accelerator, its leucocyte, erythrocyte, and platelet were observed by SEM. Also, after injecting propolis into the abdominal cavity, the radio-protective effect of blood corpuscles was studied. The observation of micromorphology in blood corpuscles revealed that the number of leukocyte, erythrocyte, and thrombocyte decreased in the experimental group and the lump got together in blood corpuscles after 10 and 20 days. In RBC, crack or break on the surface and poikilosperocytes were observed. In the irradiation group, the size of leucocytes was smaller than that in control group and the number of villus at the verge substantially decreased. The blood corpuscles in the propolis group, however, had the similar results to control group.

• The Korean Journal of Mycology
• /
• v.46 no.3
• /
• pp.249-254
• /
• 2018

Nannizziopsis mirabilis (KNU17-67) was isolated from a field soil sample collected from Jejudo in 2017. This fungal isolate was identified and described by its morphological characters and the internal transcribed spacer rDNA gene sequencing. Potato dextrose agar medium was used to study its macro and micromorphology. In addition, a molecular phylogenetic tree was constructed for its precise confirmation as N. mirabilis. This fungal isolate has not officially been reported previously in Korea.

• Journal of Korean Society on Water Environment
• /
• v.30 no.3
• /
• pp.292-297
• /
• 2014

We synthesized the self-organized nanoporous oxide with potentiostatic anodization of iron foil. The iron oxide nanocomposite (INCs) were fabricated in 1M $Na_2SO_4$ containing 0.5wt% NaF electrolyte holding the potential at 20, 40 and 60 V for 20min, respectively. Field Emmision Scanning Electron Microscopy (FESEM) and X-ray Diffractometer (XRD) were used to evaluate the micromorphology and crystalline structure of INC film. Also, this study was performed to evaluate the fenton reaction using INC film with hydroperoxide for degradation of cyanide dissolved in water. In case of INC-40V in the presence of $H_2O_2$ 3%, the first-order rate constant was found to be $1.7{\times}10^{-2}min^{-1}$, and indicated to be $1.2{\times}10^{-2}min^{-1}$ on commercial hematite powder. This result is shown to be good performance enough to replace the powder type for treatment of wastewater.

• Korean Journal of Plant Taxonomy
• /
• v.37 no.3
• /
• pp.255-273
• /
• 2007

The morphological characters for 4 taxa of Korean Symplocaceae were examined. Based on morphological examination, numerical analysis was performed to clarify the taxonomic relationships among the taxa. It was found that epidermal characters of leaves, cellular deposition of petals, cellular boundary of petioles, growth of stigmas and pollen grains and their surfaces were useful diagonostic characters. From the results of PCA analysis, four taxa were grouped as species clusters including each populations. Four species of Symplocos were clustered as species groups with clear delimitation. Morphological, numerical, and palynological analyses supported the previous morphological studies on this family.

• Korean Journal of Plant Taxonomy
• /
• v.48 no.2
• /
• pp.134-142
• /
• 2018

The achene morphology of 21 taxa of Persicaria sect. Cephalophilon including the related taxa of Koenigia (Polygonaceae) was examined using stereo microscopy and scanning electron microscopy to evaluate its diagnostic values and taxonomic implications. The outlines of achene were narrowly ovoid to broadly ovoid in general, and elliptic achenes were observed in Koenigia taxa, with the achene shape being biconvex or trigonous. The size of the P. sect. Cephalophilon taxa ranged from $0.93-3.55{\times}0.80-2.31mm$ and the size of examined Koenigia taxa ranged from $1.10-1.84{\times}0.79-1.02mm$. The smallest achenes in P. sect. Cephalophilon were observed in P. humilis and the largest achenes were found in P. chinensis var. chinensis. Furthermore, infraspecific taxa of P. chinensis had relatively large achenes compared to other taxa within the section. Most taxa of P. sect. Cephalophilon had dull achenes, while four taxa had glossy achenes (P. capitata, P. runcinata var. runcinata, P. runcinata var. sinensis, and P. sinuata). Four types of surface patterns (smooth, tubercles, small pits, and irregular ridge) were observed, and the tubercles were divided into two subtypes according to the grouping and distribution pattern. The achene morphology of P. sect. Cephalophilon is described and compared, and its taxonomic implications are also discussed.

• Advances in concrete construction
• /
• v.10 no.6
• /
• pp.515-526
• /
• 2020

Cold-mixed asphalt mixture is a widely recommended asphalt pavement materials with potentially economic and environmental benefits. Due to the reduction of natural non-renewable mineral resources, powder minerals with similar properties are considered as new mineral fillers in asphalt mixtures. This study explored the feasibility of using cement to replace natural limestone powder (LP) in emulsified asphalt concrete modified by styrene-butadiene styrene copolymer. The experimental tests, including compressive strength, Marshall stability as well as moisture susceptibility test, were used to investigate the mechanical properties, the Marshall stability, flow value, as well as the moisture damage. In addition, the influence of material composition on the performance of asphalt concrete is explained by the microstructure evolution of the pore structure, the interface transition zone (ITZ), and the micromorphology. Due to mineralogical reactivity of cement, its replacement part of LP improved the mechanical properties, Marshall stability, but it will reduce the moisture susceptibility and flow value. This is because with the increase of the cement substitution rate, the pore structure of the asphalt concrete is refined, the width of ITZ becomes smaller, and the microstructure is more compact. In addition, asphalt concrete with a larger nominal particle size (AC-16) has relatively better performance.