• Journal of Plant Biology
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• v.4 no.1
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• pp.13-15
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• 1961

1. This study was made on the flora of Hepaticae in the crater of Mt. Hanla ($33^{\circ}$20' N. Lat. $126^{\circ}$4' E. Long), Isl. Quelpart. 2. the total fo the occurring species of the crater are twelve, out of which the following 6 species are new to the Korean flora. (1) Bazzania tricrenata (Wahlenb.) Trev. (2) Plagiochila satoi Hatt. (3) Scapania ampliata St. (4) Radula boryana (Web.) Nees. (5) Cololejeunea kodamae Kamimura. (6) C. macounii (Spruce) Evans. 3. The hepaticae flora of the crater consists of the following elements: Holarctic element. 4 species (33%), East Asiatic element. 2. species (16%), Korean-Japan element. 5. species (41%), North-Pacific element. 1 species (8%).

• Journal of Forest and Environmental Science
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• v.33 no.2
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• pp.136-146
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• 2017

We selected 6 plots ($100m^2$) located 2.2-3.8 km from Minamidake Crater on the north flank of Sakurajima Volcano. We conducted a field study to investigate the effects of volcanic activity on vegetation succession and surface erosion rate. The results showed that trees growing in plots further from the crater had a greater diameter at breast height (DBH), total height, and age. In addition, these plots had a greater number of woody plants and species, as well as a greater total cross-sectional area at breast height. The Fisher-Williams index of diversity (${\alpha}$) and the proportion of evergreen broad-leaved trees were higher in plots located further from the crater. Vegetation succession in these plots was not at the level of a climax forest. From 1972 to 2015, the timing for active volcano, the depth of volcanic ash layer, the dry density, and the pH of ground surface were lower for plots located further from the crater. Furthermore, the average annual sheet erosion from 1972 to 2015 was also lower for plots located further away from the crater. Overall, plots further away from the crater have a better environment for vegetation growth and a lower dry density of the volcanic ash surface layer. It is thought that lower dry density results in increased soil permeability, which impedes surface flow. In order to prevent debris-flow disasters, caused by mud and rock flow resulting from impaired soil penetrability, it is essential to promote soil development and restore penetrability by artificial vegetation restoration.

• Journal of Welding and Joining
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• v.34 no.6
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• pp.62-68
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• 2016

Laser welding has superior characteristic such as low distortion, high welding speed, easy automation and real time control. But it is easy to occur weld defects such as porosity, crater, humping bead in the area of welding start and end. These weld defects can be suppressed by applying the wave shape control. In this study CW fiber laser was used for welding of $0.5mm^t$ pure titanium. Penetration properties were evaluated with the time of slope up and down. After then the bead shape was observed, and the maximum depth and the area of crater were measured. The bead shape of welding start area changed to be sharp with increase of slope up time and non-weld area of welding start increased. The crater and humping bead were suppressed with slope down time. The cooling rate of crater area was understood through measure of the hardness. Also, The distribution tendency of alloying elements was observed by EPMA and EDS. When wave shape control didn't applied to weld, the hardness of end weld increased due to rapid cooling rate and the hardness of rear part in the crater was higher than that of fore part. On the other hand, when the wave shape control was used for end weld, the increase of hardness in the end weld couldn't be found due to gradual cooling rate.

• Proceedings of the Korean Powder Metallurgy Institute Conference
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• 2001.11a
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• pp.46-46
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• 2001

The microstructure of the 1020 mild steel target in the region ahead of craters, made by colliding against Cu and W-Cu shaped-charge jets. has been investigated in the present work. The region ahead of the crater impacted by the Cu shaped-charge jet reveals grain refinement implying the formation of sub-grains, while that of W-Cu one leads to martensitic transformation indicating that the region was heated up to an austenitic region which was followed by rapid cooling. The pressure of W-Cu shaped-charge jet impacting against the target when calculated is higher than that of Cu one. The microhardness of the region ahead of the crater impacted by the W-Cu shaped-charge jet is also higher than that of the Cu one. The microstructure of W-Cu slug that remains inside of the crater depicts the occurrence of the remarkable elongation of W particles during the liner collapse. The microstructural evolution of the region ahead of the crater is discussed on the basis of the pressure dependency of the ferrite/austenite transformation in the steel.

• Journal of Environmental Science International
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• v.11 no.7
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• pp.669-677
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• 2002

This study was conducted to investigate the characteristics of role of transport on aerosol concentration at Crate Lake, Oregon USA for 1988.3~1999. 5. The IMPROVE program is a cooperative measurement effort governed by a steering committee composed of representatives from USA federal and regional-state organizations. Also IMPROVE sampler is designed to obtain a complete signature of the composition of the airborne particles affecting visibility. According to 10-day backward isentropic trajectory analysis, the frequency of local, marine and Asian trajectory showed 33.1%(335 cases), 47%(478 cases), 5.2%(53 cases) respectively. The monthly variation of nss $SO_4^{2-}$, nss S, $NO_3^-$, K and C showed the double peak pattern, high in April~May and August~september and showed the lowest concentration in Winter. The other constituents concentration except for Cl$^{[-10]}$ , Na, Mg was high in local trajectory than marine trajectory. A ratio nss $SO_4^{2-}$ to $SO_4^{2-}$ was 90.5% in marine trajectory and 98% in local trajectory. It suggest that the aerosol in Crater Lake was effected by salt. The annual mean concentration of nss $SO_4^{2-}$ and nss S decreased but the springtime concentration increased.

• Korean Journal of Remote Sensing
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• v.32 no.5
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• pp.403-412
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• 2016

Compact Reconnaissance Imaging Spectrometer for Mars(CRISM) is 489-band hyperspectral camera of Mars Reconnaissance Orbiter(MRO) that provided data used on many mineral researches over Martian surface. For the detection of minerals in planet, mineral index using a few spectral bands have been used. In this study, we applied Matched Filter and Adaptive Cosine Estimator(ACE) target detection algorithm on CRISM data over Gusev Crater: landing site of Spirit(Mars Exploration Rover A) to investigate its mineral distribution. As a result, olivine, pyroxene, magnetite, etc. is detected at Gusev Crater's Columbia Hills. These results are corresponding to the Spirit rover's field survey result. It is expected that hyperspectral target detection algorithms can be used as effective and easy to use method for the detection and mapping of surface minerals in planet.

• Proceedings of the Korean Society of Precision Engineering Conference
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• 1996.11a
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• pp.3-8
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• 1996

To enhance the cutting performance of the tool, single or multilayer coating is applied on the substrate of the tool. Coating material reduces cutting force and heat generation in tool-chip contact zone and enhances resistance against abrasive wear. This paper presents that the effect of different coatings on abrasive wear resistance varies with work material and the flank wear rate is different with depth of cut. Crater wear rate is also found to decrease with higher thermal diffusivity of coating material. It is verified that the estimated thermal diffusivity of multilayer coating has consistent effect on the crater wear.

• Proceedings of the Korean Society of Precision Engineering Conference
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• 2002.10a
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• pp.709-712
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• 2002

For the electro-discharge machining of an electro-conductive anisotropic composite, an unsteady state formulation was established and solved by Galerkin's finite element method. The distribution of temperature on work piece, the shape of the crater and the material removal rate were obtained in terms of the process parameters. As the spark was initiated the workpiece immediately started to melt and the heat affected zone was formed. The moving boundary of the crater was also identified with time. When the radial and axial conductivities were increased separately the temperature distribution and the shape of the crater were shifted in the same direction respectively and the material removal rate was found to be higher in the case of increasing radial conductivity rather than the axial conductivity.

• Journal of the Optical Society of Korea
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• v.18 no.1
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• pp.50-54
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• 2014

In this paper we studied the laser-induced crater depth, mass, and emission spectra of laser-ablated high-density polyethylene (HDPE) polymer using the laser-induced plasma spectroscopy (LIPS) technique. This study was performed using a Nd:YAG laser with 100 mJ energy and 7 ns pulse width, focused normal to the surface of the sample. The nanoscale change in ablated depth versus number of laser pulses was studied. By using scanning electron microscope (SEM) images, the crater depth and ablated mass were estimated. The LIPS spectral intensities were observed for major and minor elements with depth. The comparison between the LIPS results and SEM images showed that LIPS could be used to estimate the crater depth, which is of interest for some applications such as thin-film lithography measurements and online measurements of thickness in film deposition techniques.

• Transactions of the Korean Society of Mechanical Engineers A
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• v.20 no.12
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• pp.3759-3766
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• 1996

In this paper a new gefchmique to measaure the creater wear using image processing and automatic focusing is presented. The contour detection algorithm, which can adopt ina noisy image, is suggested. It is suitable for eliminating high frequency noses with lower processing time and without blurring. An automatic focusing technique is applied to measure a createrwear depth with a one-dimensional search algorithm for finding the bestfocus. This method is implemented in the tool microscope driven by a servo motor. The results show that the countour and depth of crater wear can be measured reliably.