• 한국정밀공학회지
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• 제25권12호
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• pp.125-131
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• 2008

In the past, precision optical glass lenses were produced through multiple processes such as grinding and polishing, but mass production of aspheric lenses requiring high accuracy and having complex profile was rather difficult. In such a background, the high-precision optical GMP processes were developed with an eye to mass production of precision optical glass parts by molding press. Generally because the forming stage in a GMP process is operated at high temperature above $570^{\circ}C$, thermal stresses and deformations are generated in the aspheric glass lens mold that is used in GMP process. Thermal stresses and deformations have negative influences on the quality of a glass lens and mold, especially the height of the deformed glass lens will be different from the height of designed glass lens. To prevent the problems of a glass lens mold and the glass lens, it is very important that the thermal stresses and deformations of a glass lens mold at high forming temperature are considered at the glass molds design step. In this study as a fundamental study to develop the molds used in an aspheric glass lens fabrication, a heat transfer and a thermal stress analysis were carried out for the case of one cavity glass lens mold used in progressive GMP process. Finally using analysis results, it was predicted the height of thermally deformed guide ring and calculated the height of the guide ring to be modified, $64.5{\mu}m$. This result was referred to design the glass lens molds for GMP process in production field.

• 한국주조공학회지
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• 제18권6호
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• pp.578-585
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• 1998

A multi-purpose code MAGMA was employed for mold design and process control in producing Al wheel by lowpressure die casting. Three-dimensional solid modeling was followed by mesh generation of casting and molds(top, bottom and side). The simulation of stability of casting cycle time, mold filling simulation with pressure variation from P1 to P2, solidification simulation by solidification time and feeding criteria, and temperature distribution of molds during processes were studied in this research. The thermal stability of molds was attained after 5 cycles when molds were preheated at $400^{\circ}C$. The pressure increase from P1 to P2 for mold filling was evaluated as slightly higher, and 6 seconds were taken for the mold filling. The cycle time was believed to be designed properly judged from the solidification time of casting and open/close time of molds.

• Preventive Nutrition and Food Science
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• 제3권1호
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• pp.43-47
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• 1998

The incidence of total molds, Fusarium species, and the estrogenic mycotoxin,zearalenone, in Korean grain samples were investigated . The majority of molds infecting grain were identified as belonging to the genus Alternaria , with an average infection rate of kernels of 43% and 32% in rice and baley, respectively. Fusarium speciens were less common, with average infection rates of 13% and 19% in reice and barley, respectively. A number of field fungi including Curvularia and Dactylaria were also observed. Among the Fusarium speices, 71 of 94 Fusarium isolates were identified as F.semitectum. A few F. moniliforme and F. equiseti were observed linked immunosorbent assay (ELISA) or high-performance liquid chromatography(HPLC). In addition, deoxynivalenol was not deteted by ELISA . However, thepresence of molds, including Fusarium species, may pose possbile health hazards to persons consuming those grains.

• 한국기계가공학회지
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• 제20권2호
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• pp.120-125
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• 2021

Phylon molds are widely used for injection molding of foams used in shoe outsoles. Injection pylon molds are usually prepared by first casting the aluminum alloy and then applying an anodized coating to improve durability. This study was carried out to examine the durability of aluminum phylon molds. The aluminum materials used in this study were A771, A6061, and AC4C, and their mechanical properties were compared. Specimens for anodic oxidation tests were prepared with coating thicknesses of approximately 10 and 40 ㎛. We tried to select the optimum material and coating thickness suitable for fabricating phylon injection molds. Among the three materials, A6061 exhibited the best tensile, wear, and impact properties. The difference in the wear resistance between the soft- and hard-anodized coatings was insignificant.

• Design & Manufacturing
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• 제2권5호
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• pp.11-15
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• 2008

A micro-injection mold for ultra-thin-walled plate was considered in this work. The proposed mold system is for the fabrication of ultra-thin walled plastic plate with micro features by injection molding. As the injection molding of thin-walled plastic, which has the thickness under $400{\mu}m$, itself is not easy, the injection molding of the micro-features in the thin-walled structure is more complicated and difficult. To investigate the basic phenomenon of the ultra-thin walled part during the injection molding process, design of the part and mold system were performed in the present study. The injection molding and structural analysis of the suggested part and mold system were also performed. Consequently, injection molding system for ultra-thin walled plate with micro features were manufactured and presented.

• 산업경영시스템학회지
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• 제41권4호
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• pp.248-255
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• 2018

Ensuring the quality of molds is one of the major issues in mass production. In general, securing the quality of the molds is achieved by repeating grinding and die spotting after machining the molds based on engineer's decision. However, this heuristic method is affected by the engineer's skill and working environment. Therefore, a lot of time and resources are needed in order to ensure quality. In this study, ensuring the quality of molds using grinding map which is generated using automatic measurement is proposed. An automatic measuring system based on CMM (Coordinate Measuring Machine) is developed for measuring the molds. This system generates the measurement path automatically using the 3D CAD model of products. CAD (ComputerAided-Design), CAM (Computer-Aided-Manufacturing), and CAQ (Computer-Aided-Quality) technology is integrated using DMIS (Dimensional Measuring Interface Standard) format in the automatic measuring system. After measuring the molds, a grinding map is generated using the gap between the CAD model and measured values of mold. The grinding map displays the machining tendency and the required amount of grinding with values on a 3D map. Therefore, the quality of molds can be ensured with exactness and quickness based on the grinding map. This study shows that integrating the planning, measuring, and analyzing based on computer technology can solve the problem of quality assurance of mold using the proposed method, therefore the productivity can be increased.

• Applied Biological Chemistry
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• 제42권4호
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• pp.356-360
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• 1999

감귤저장 방법의 개선과 감귤 껍질의 효율적인 활용을 위해서 시판 중인 농약제제와 감귤정유의 감귤부패 관련 사상균에 대한 살균 작용을 조사하였다. Alternaria alternata, Rhizopus sp., Botrytis cinerea, Monilia candida, Penicillium italicum, Penicillium digitatum 등 6종의 사상균에 대한 시판 합성 농약제제 11종의 생육저해 효과를 조사한 결과, mancozeb 또는 fluazinam을 함유한 제제의 활성 범위가 가장 넓었고, conazole 계통의 화합물이 중간 정도의 활성 범위를 나타내었으며, iprodione, benomyl, azoxtrobin 또는 thiophanate을 함유한 제제의 항균활성 범위가 가장 좁은 것으로 나타났다. 농약제제의 생육저해 효과는 대상 균주에 따라 달랐으며, Penicillium italicum과 Alternaria alternata는 각종 살균제의 처리에 대한 생존력이 비교적 강하였다. 감귤정유를 상기 6개 균주의 포자와 각각 접촉시켰을 때는 그 어느 균주의 생존 포자도 검출되지 않았으며, 감귤정유의 살균력은 paper disk법과 현미경 관찰로도 증명되었다. 이는 감귤정유가 광범위한 살균력을 지니고 있음을 제시한다. 따라서 감귤 정유를 감귤저장에 활용하는 방법을 검토할 필요가 있다.

• Design & Manufacturing
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• 제1권1호
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• pp.1-5
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• 2007

Double injection molding process is very efficient molding-method for molding the products which is consist of multi-materials. Fuel-tube holder which is necessary for automobil power train and circulation systems is composed of plastic and rubber materials to minimize the vibration and pulsation noises. In existing process, fuel-tube holder was made by the insert molding process or assembly process after molding. If fuel-tube holder is manufactured by double injection molding process, it may be realize to improve the product quality, efficiency of molding-process and retrenchment of manufacturing cost. In this study, for manufacturing fuel-tube holder by double injection molding process, the analysis of joining characteristics between PA6(polyamide 6) and TPE(thermoplastic elastomer) was executed and the double injectin mold for molding fuel-tube holder with core toggle mechanism was fabricated. Finally, fuel-tube holder was molding using fabricated double injection mold.

• 한국주조공학회지
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• 제2권1호
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• pp.2-11
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• 1982

In order to investigate the relationship between the thermal characteristics of the various molds as green sand mold, dry sand mold, $CO_2$ mold and shell mold, and the solidification characteristics of molten metal, the thermal analysis of rarious molds and melt were performed. The structure of Al-Castings was a/so observed. Results obtained in this experiment were as follows : 1) The heating rate of the molds was increased in the order of green sand mold, $CO_2$ mold, dry sand mold and shell mold, On the other hand the solidification time of the melts was shortened in the order of dry sand mold castings, $CO_2$ mold castings, green sand mold castings and shell mold castings. 2) The arrest temperature period in the heating curve of the green sand mold was resulted from the eraporation of moisture contained in mold, which was transfered to the outer side of the mold. 3) The temperature fluctuation of the melt in the shell mold was considered to be resulted from the combution heat of resin contained in the mold. 4) The amounts of heat absorption of the molds were increased in the order of dry sand mold, $CO_2$ mold, green sand mold and shell mold. 5) The higher the solidification rate was, the longer was its shrinkage pipe and the finer its grain size.

• 아시안잔디학회지
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• 제10권3호
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• pp.195-211
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• 1996

Dictyostelids cellular slime molds were isolated from the soils of Gokneung and Anyang streamside in Korea. The fifteen species including two undescrihed species were identified. These were as follows ; Dictyostelium macrocephalurn D. sphaerocephalum, D. aureum var. aureum, D.mucoroides, D. minutum, Polyspondyium pallidum. D. giganteum, P. violaceum. D. purpureum. D.brefeldianum, D. flavidum, D. mucoroides var. storoniferum, D. septentrionalis, D. aureum var. luteolum,D. aureo-stipes var. aureo-stipes. D. macrocephalum was the dominant species. and D. sphaerocephalum. D. aureum var. avreum were relatively common. D. mucoroides var. storoniferum, D. septentrionalis were the undescrihed species in Korea. In the soils of streamside, dominant species was shifted by D. macrosephalum, D. sphaerocephalum. which were rare in the forest soils. The total clones per gram of streamside soils were greater than that of forest soils, whereas the number of species in streamside was smaller than the in forest soils. As a result, the ratio of the number of clones to species was very high in the soils of streamside, Environmental factors of soil pH, water content, organic content, total nitrogen and total phosphorus made a effect differently on the cellular slime molds community. Key words: Cellular slime molds, D. macrocephalum, D. sphaerocephalum, Shift of dominant species, Environmental factors.