• Proceedings of the Korean Society for Technology of Plasticity Conference
• /
• 2005.10a
• /
• pp.389-392
• /
• 2005

Sandwich structures, which are composed of a thick core between two thin faces, are commonly used in many engineering applications because they combine high stiffness and strength with low weight. In this paper, through the FLD analysis according to the pattern changes, we have confirmed the deformed shape and formability distribution. Also, we have fabricated the dimple press mold according to the pattern changes, and obtained the dimple inner structure the forming experiments.

• Proceedings of the Korean Society for Technology of Plasticity Conference
• /
• 1997.10a
• /
• pp.65-71
• /
• 1997

Computer simulations and test trials are carried out to get the optimal conditions about the stamping die design of the tailor laser welded automotive door inner. Firstly, the stamping process including gravity deflection, bead calibration, binder wrap, forming and spring back, are analyzed by the computer simulation. The results of simulation shows good correspondance with those of test trial under the same conditions. The variables of parametric study which will be investigated in the simulation and test trials, are determined form the results of the first run. The formability under the various conditions is evaluated, which are the initial postion of blank, blank holding force, corner radius and the shape of drawbead. Finally, well controled sound product without fracture, wrinkling and excessive weldline movement is obtained.

• Korean Institute of Interior Design Journal
• /
• v.16 no.3 s.62
• /
• pp.111-118
• /
• 2007

Using effective light, which is physical experiences by its control and manner of adaption, and make human to recognize the shape and give the meaning, so that approaching against perception experimental method which plays a role in basic clue, is regarded crucial highly among human sensory organ. this study consider the perception conception, its feature and necessity against eyes' adaption among human perception experimental experiences which has been discussed indifferently for inner space. Also, we looked over the problems among actual examples of inner spaces which should be considered as to adaption conception of human beings. Furthermore, this study aims at basic studying, which searching for enable to adapt in case of planning for inner space planning and distributing the quality evaluation by using effective light.

• Journal of the Korean Institute of Illuminating and Electrical Installation Engineers
• /
• v.30 no.2
• /
• pp.71-77
• /
• 2016

The dielectric barrier discharge (DBD) has low efficiency due to about 70% input power is consumed as thermal energy in the discharge space. However, because of the usage of DBD ozone generator is easier than other methods. The DBD ozone generator has been widely applied for high concentration ozone generation in the industrial application. But, the low-capacity compact DBD ozone generator is not applied so far. Therefore, the DBD ozone generator is necessary to improve ozone production efficiency and reduce the capacity. In this paper, the stainless steel pipe inner electrode was designed with hall type and screw type to improve the ozone production yield. The manufactured two inner electrodes were experimented with normal type for comparison of the discharge characteristics and the ozone generating characteristics. As the experimental results, the discharge current effective value of designed inner electrodes with hall type and screw type are higher than the normal type, due to unequal electric field is formed at the boundary. However, the difference of designed and original electrodes is less than 0.1mA that has no effect on the discharge characteristic. On the other hand, the screw type inner electrode increased higher than original model about 7 times when the flow rate of the oxygen source gas was increased from $0.6{\ell}/min$ to $1.0{\ell}/min$ The reason was assumed by the flow rate of the raw gas through the inner electrode was became fast that has a cooling effect. The designed hall type and screw type inner electrodes have shown good performances in ozone generation and ozone production that better than normal type in the same electrode surface area.

• Journal of Plant Biology
• /
• v.38 no.2
• /
• pp.181-193
• /
• 1995

Cuticle micromorphology of four families of Korean gymnosperms, Cycadaceae, Ginkgoaceae, Taxaceae, and Cephalotaxaceae, were studied with scanning electron microscopy. The outer and inner features of abaxial and adaxial cuticles were described in details; the absent or present of Florin ring, orifice, trichome, and plug and their shape, the shape and periclinal and anticlinal wall sculpture of epidermal cells, the shape of cuticular flange of epidermal cell, guard cell, and subsidiary cell, the number of stomatal bands and rows, and stomatal apparatus including the shape of polar extension, number of subsidiary cells, the sculpture of guard cell and subsidiary cell. Most of these features have not been sufficiently substantiated by the previous reprots. Furthermore, all the species investigated showed distinctive cuticle morphology with morphological and taxonomical informations.

• Journal of the Korea Institute of Military Science and Technology
• /
• v.3 no.2
• /
• pp.244-249
• /
• 2000

Thermal gradient chemical vapor infiltration (TG-CVI) process, which is one of the CVI techniques to densify a porous fiber preform, requires for a heater to have uniform surface temperature distribution. Thus, it is essential to design the shape of the heater and to predict the temperature distribution when the heater has a profile which is not a simple cylinder. In this study, an analytical method has been used to design the inner profile of a conical heater showing uniform temperature distribution, if its outer shape is specified. Temperature distribution on the heater surface has been calculated with the finite difference method and compared with the experimental results. When a heater had a combined profile with a large cone and a small cylinder, temperature was higher in the cylindrical part. To reduce the temperature difference between these areas, a hole-machining method has been proposed including other possible ones. A shape design and optimization program has been made to improve the temperature uniformity of the TG-CVI heater better than that designed with the analytical method.

• Transactions of Materials Processing
• /
• v.10 no.3
• /
• pp.193-199
• /
• 2001

Forming more than two parts of sheet metal in a single stamping operation lowers production costs, reduces weight, and heightens dimensional accuracy. The tailored blank (TB) is a laser-welded or mash-seam-welded sheet metal with different thicknesses, different strengths, or different coatings. Recently, automotive manufacturers have been interested in tailored blanks because of their desire to improve the rigidity, weight reduction, crash durability, and cost savings. Therefore the application to auto-bodies has increased. However, as tailored blanks do not behave like un-welded blanks in press forming operations, stamping engineers no longer rely on conventional forming techniques. Field try-outs are very important manufacturing processes for an economic die-making. In the field try-outs, the rounded geometries of tool and the drawbead shape and size in die face are generally modified when the forming defects can not be removed by the adjustment of forming process parameters. In this study, the field try-outs of tailored door inner panel are introduced and evaluated. The behaviours of laser tailored blank associated with different thickness combinations in the forming process of door inner panel are described focusing on terms of experimental investigations on the formability.

• Korean Journal of Environmental Biology
• /
• v.40 no.4
• /
• pp.374-386
• /
• 2022

Phytoplankton communities, with emphasis on picoplankton and nanoplankton, were investigated in Gamak Bay, South Korea, where freshwater input and coastal water intrusion shape ecosystem functions. Shellfish farms and fish farms are located in the inner bay and outer bay, respectively, and tides translocate uneaten food and urine production from aquaculture farms toward the inner bay. Water masses were distinctly different based on a significantly different density between the surface and bottom layer and among three water masses, including the inner bay, outer bay, and Yeosu Harbor. Phytoplankton communities were quantified using flow cytometry and size-fractionated chlorophyll-a (chl-a) was measured. Salinity was a principal variable separating phytoplankton communities between the surface and bottom layer, whereas Si(OH)₄ controlled the communities in the inner bay, and NH₄⁺ and PO₄^3- governed the outer bay communities. While phycocyanin-containing (PC) cyanobacteria dominated in the outer bay, phycoerythrin-containing (PE) cyanobacteria dominance occurred with cryptophyte dominance, indicating that nutrients affected the distribution of pico- and nanoplankton and that cryptophytes potentially relied on a mixotrophic mode by feeding on PE cyanobacteria. Interestingly, picoeukaryotes and eukaryotes larger than 10 ㎛ were mostly responsible for the ecological niche in the western region of the bay. Given that chl-a levels have historically declined, our study highlights the potential importance of increased small phytoplankton in Gamak Bay. Particularly, we urge an examination of the ecological role of small phytoplankton in the food supply of cultivated marine organisms.

• Conservation Science in Museum
• /
• v.25
• /
• pp.1-8
• /
• 2021

This study investigated White Porcelain Water Dropper with Openwork Lotus Scroll Design and Eight Trigram Design in Cobalt-blue Underglaze (hereinafter, the "water dropper") in the collection of the National Museum of Korea using computed tomography (CT). A replica was produced to examine both the structure and its original production method. The CT scanning identified no joint lines or pores in the clay, which suggests that the body (the lower part of the water dropper) was shaped in a single piece using a mold and was then matched with a mold-formed lid (the upper part of the water dropper). The inner container of the body portion was roughly trimmed with a bamboo knife so that its upper surface could be securely attached to the bottom of the lid and prevent any leakage in the joined surface. It appears that the inner container for storing water was made first in a cylindrical shape that met the unit of quantity used at the time and could be easily formed by molding. It was transformed into a trapezoid shape during the process of combining it with the lid. A cylindrical inner container was reproduced using silicon 3D printing to compare its capacity with that of the original inner container. The comparison revealed that the reproduced container had a capacity of 152.5㎖, whereas the original container holds approximately 168.6㎖, a figure similar to three hop (around 174㎖) in Joseon-period units of quantity. Since the capacity of the cylindrical inner container corresponds to a known measure from the late Joseon dynasty, it is likely that the water dropper was originally produced to contain a cylindrical inner container.

• Journal of the Korean Society of Safety
• /
• v.31 no.6
• /
• pp.93-98
• /
• 2016

This study analyzed the inflow characteristics of debris flow according to shape of defensive structure and computed risk index. In order to simulate debris flow, two shapes of defensive structure were considered. Initial mass distribution was set with a rectangular shape and defensive structures were set semi-circular shape and rectangular shape, respectively. It was found that a defensive structure with semicircular shape was more vulnerable to debris impact compared with rectangular shape because the flow mass became concentrated in quadrant part of the inner circle. If the velocity of the debris flow was less than 1 m/s, the risk assessment by FII (Flood Intensity Index) was much appropriate. However, when the movement of debris runout was faster than 1 m/s, the risk index of FHR (Flood Hazard Rating) provided improved classification due to its subdivided hazardous range.