• Journal of the Korean Society for Precision Engineering
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• v.14 no.3
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• pp.41-49
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• 1997

Laser spot welding offers a unique combination of high speed. precision and low heat distortion, compared with conventional resistance spot welding. This combinatin of advantages is especially attractive for the automotive industry. Until now automobile fabrication is widely used resistance spot welding, however, because of geometric and structural problem, spot welding is required many welding machine in that reason by substituting spot welding with laser welding, it save the equipment cost. In the present study we measured ultimate strength and observed bead cross section of laser welded specimen and compared with that of the resistance spot welding results in order to adapt laser welding in automobile industry. Also for strength esti- mation we calculated the residual stress of laser welded zone. All calculations are performed with the ABAQUS code on a workstation.

• Transactions of the Korean Society of Mechanical Engineers A
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• v.27 no.3
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• pp.387-392
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• 2003

The mechanical behavior of two rectangular spot-welded plates under bending is investigated in detail. The equivalent thickness of spot-welded plates is introduced in this study and used in explaining the results. The focus of the analysis is to evaluate the effect of spot-welding from the view point of equivalent thickness. The investigation of deflection has been performed as comparing the result from finite element analysis with the measured data of the spot-welded plates for various parameters, such as aspect ratio, area ratio, and distance ratio of spot-welding points. The effect of spot-welding is as large as 62%(at r=1.0) when the area ratio of spot-welding point is just 4.52%.

• Proceedings of the KSME Conference
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• 2001.06a
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• pp.175-180
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• 2001

In real structure, multi-point spot welded joints are more frequently used than a single-point spot welded joint. Most researches, however, have been focused to a single-point spot welded joint until now. In this paper, the fatigue behavior of multi-point spot welded joints are investigated both experimentally and analytically using the finite elements. The local strain approach is used rather than the stress intensity factor approach to estimate the fatigue life since the former is quite simple and straightforward. It is found that the fatigue behavior of multi-point spot welded joints is different from that of single-point spot welded joints. The local strain approach is still applicable to multi-point spot welded joints.

• Korean Journal Plant Pathology
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• v.14 no.5
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• pp.473-483
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• 1998

This paper is the sixth report about the fungal diseases of economic resource plants observed newly in Korea. It contains short descriptions on symptoms, occurrence conditions, pathogens, and some phytopathological notes for each of 10 fungal plant diseases. They are identified as circular leaf spot of Ligustrum ovalifolium by Cercospora adusta, leaf spot of Viola spp. by c. violae, leaf spot of Trifolium repens by C. zebrina, hypophyllous leaf sot of Angelica gigas by Passalora depressa, brown leaf spot of Euonymus japonicus by Pseudocercospora destructiva, brown leaf spot of Lonicera japonica by P. lonicericola, brown leaf spot of Parthenocissus tricuspidata by P. vitis, black spot of Echinops latifolius by Ramularia cynarae, leaf spot of Petasites japonicus by R. major, and leaf spot of Plantagoasiactica by R. plantaginis, respectively.

• International Journal of Industrial Entomology and Biomaterials
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• v.12 no.1
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• pp.35-39
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• 2006

Fifty-six indigenous and twenty nine exotic mulberry varieties were screened against powdery mildew, Myrothecium leaf spot, Pseudocercospora leaf spot, sooty mold and bacterial leaf spot for a period of three years under field condition. The percent disease index (PDI) was recorded during peak season of the foliar diseases. Out of eighty-five varieties studied, ten varieties were highly resistant and eight were resistant to powdery mildew; six varieties were immune and seventy-eight varieties were highly resistant to Myrothecium leaf spot; sixty varieties were highly resistant and 21 were resistant to Pseudocercospora leaf spot; forty four varieties were highly resistant to sooty mold and two varieties were immune and fifty-eight were highly resistant to bacterial leaf spot. Lowest cumulatative disease index was observed in M. multicaulis (7.28) followed by Thailand lobed (7.85) and Italian mulberry (8.06).

• Journal of the Korean Society of Surveying, Geodesy, Photogrammetry and Cartography
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• v.9 no.2
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• pp.103-113
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• 1991

The accuracy of input coordinates of ground control points and check points affects great influences to the results of ground coordinate computation in using SPOT digital image data. The original SPOT images displayed on CRT are not usually adequate for identifying the object features and determining the point positioning. Hence, appropriate image processing techniques such as contrast enhancement, subpixel interpolation, edge enhancement, and spatial filtering are needed. In this study, the principles of digital image processing needed for accurate three dimensional positioning and spectral characteristic analysis are investigated. The algorithms for the actual applications are developed and programmed. And using the developed image processing software, some SPOT P-mode and XS-mode images are merged into the SPOT P＋XS, the high-resolution color composite image.

• The Journal of Korean Medicine Ophthalmology and Otolaryngology and Dermatology
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• v.9 no.1
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• pp.16-24
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• 1996

In order to satisfy the demand of good treatment of Oriental medicine, I investigated many books mentioned about Liver spot. The results were as follows: 1. They have called the Liver spot many other terms in the oriental medicine. 2.. The Liver spot is facial disease, so it is deeply related with yang-myong kyong(陽明經) 3. As the external cause of the Liver spot, wind and fire evil have been emphasized. 4. Intoxication of bud of banha(半夏) poison and alcohol absorption can be one of the causes. 5. As the internal cause of the Liver spot, each other vapour asthenia fever from constipation seven modes of emotion, asthenia of the spleen and stomach and insufficiency of kidney-yin(腎陰) 6. Nowadays, the deficiency of kidney-yang(腎陽) is also included as the cause of the Liver spot. 7. Many oriental doctors have talked about the relationship between the Liver spot and women, but I can't find any concrete talking about the relationship between menstration and the Liver spot, pregnancy and the Liver spot. 8. They have administrated many other herb medicines for the treatment the Liver spot.

• Journal of the Korean Ceramic Society
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• v.43 no.10 s.293
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• pp.619-625
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• 2006

The study was intended to investigate production tools and conditions of oil spot following calculating optimal composition of oil spot tenmoku glaze which can be produced at 1250$\sim$l260$^{\circ}C$. Since oil spot is influenced by the viscosity of glaze, viscosity of various glazes fit for oil spot production was determined by an SciGlass 6.0-based calculating method. Applied amount and calcinating conditions of the resulting substance of oil spot, $Fe_2O_3$, were analyzed. As a result, the viscosity of the glaze durable at 1260$^{\circ}C$ was found to range from 4.2 to 4.4, natural cooling was used after oxidizing calcinations at 1260$^{\circ}C$ for an hour, and the best oil spot tenmoku was produced by the natural cooling process after 1 h calcinations at 1150$^{\circ}C$ in the middle of natural cooling. Also, the study showed that thickness of glaze was found to have an effect on the production of oil spot and resulting oil spot was filled mostly with $Fe_2O_3$.

• Transactions of Materials Processing
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• v.23 no.5
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• pp.282-288
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• 2014

It is difficult to control welding variables during spot welding of non-ferrous metals like aluminum because of the low electrical resistance of the material. It has been suggested that a solid state welding process such as friction stir spot welding or extru-spot welding can be used to spot weld aluminum plates. In the extru-spot welding, there is a need to increase the weld strength by improving the shape of the welding die. The current study shows that the weld strength for an extru-spot welding can be increased by using a pin placed on the inside of the upper electrode in the welding die. In the current study, the deformed shape of the insert rivet and the stress distribution in the welding zone were analyzed by simulation. Extru-rivet spot welding experiments were performed by changing the height of pin on the inside of the upper electrode. From the experimental result, it is shown that the weld strength for an extru-rivet spot welding can be increased by adjusting the height of the pin. The optimal shape of the deformed rivet after the extru-rivet spot welding can be observed from the simulation results. The deformed shape of the insert rivet can also be controlled by the height of pin.

• KSCE Journal of Civil and Environmental Engineering Research
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• v.12 no.1
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• pp.151-158
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• 1992

Topographic mapping from economic SPOT stereo imagery than aerial photographs has become possible. Many of authors have studied the possibility of base map revisions and the accuracy of results. They have concluded that the SPOT image is suitable for 1/50,000 to 1/100,000 topographic map. For topographic map, orthophoto and DTM generation from SPOT imagery, accurate exterior orientation parameters are needed. But since the geometric characteristic of SPOT image is dynamic linear array imagery, the conventional bundle adjustment for photogrammetry can not be directly applied. Reliability is the ability to detect gross error, which is called the internal reliability, and the effect of non-detectable gross error on the results of exterior orientation, which is called the external reliability. This paper shows how the reliability of SPOT imagery depends on the different coordinate systems, presentations of coordinate for flight direction, orders of exterior orientation parameters and distribution of control points, and thus analyses the theoretical reliability of the exterior orientation, which can provide a basis for the planning of SPOT projects.