검색결과

검색조건
좁혀보기
검색필터
결과 내 재검색

간행물

    분야

      발행연도

      -

        검색결과 14

        1.
        2024.02 KCI 등재 구독 인증기관 무료, 개인회원 유료
        By developing molds and facilities to horizontally mold the functional part of the dry-cast concrete block, We intend to develop molds and a series of facilities to horizontally mold the functional part of the dry-cast concrete block to increase production per cycle while maintaining existing production methods and major facilities. In order to do so, CAE analysis is first required to develop molds and facilities for horizontally molding the functional part of the drycast concrete block in the horizontal direction. The procedure will be carried out by reviewing the validity of boundary conditions and physical properties, 3D modeling, grid generation, construction of analysis models, model validity, analysis according to frequency changes, and analysis according to physical properties. First, through the comparison of two-point support, three-point support, and two-point and three-point support in the constraint conditions, We would like to compare it with the actual molded product in the horizontal direction. But first of all, it is considered two-point support in the constraint conditions in this paper.
        4,300원
        3.
        2022.12 KCI 등재 SCOPUS 구독 인증기관 무료, 개인회원 유료
        In existing ceramic mold manufacturing processes, inorganic binder systems (Si-Na, two-component system) are applied to ensure the effective firing strength of the ceramic mold and core. These inorganic binder systems makes it possible to manufacture a ceramic mold and core with high dimensional stability and effective strength. However, as in general sand casting processes, when molten metal is injected at room temperature, there is a limit to the production of thin or complex castings due to reduced fluidity caused by the rapid cooling of the molten metal. In addition, because sodium silicate generated through the vitrification reaction of the inorganic binder is converted into a liquid phase at a temperature of 1,000 °C. or higher, it is somewhat difficult to manufacture parts through high-temperature casting. Therefore, in this study, a high-strength ceramic mold and core test piece with effective strength at high temperature was produced by applying a Si-Na-Ti three-component inorganic binder. The starting particles were coated with binary and ternary inorganic binders and mixed with an organic binder to prepare a molded body, and then heat-treated at 1,000/1,350/1,500 °C to prepare a fired body. In the sample where the two-component inorganic binder was applied, the glass was liquefied at a temperature of 1,000 °C or higher, and the strength decreased. However, the firing strength of the ceramic mold sample containing the three-component inorganic binder was improved, and it was confirmed that it was possible to manufacture a ceramic mold and core via high temperature casting.
        4,000원
        4.
        2018.12 KCI 등재 구독 인증기관 무료, 개인회원 유료
        Mold grows more easily when humidity is higher in indoor spaces, and as such is found more often on wetted areas in housing such as walls, toilets, kitchens, and poorly managed spaces. However, there have been few studies that have specifically assessed the level of mold in the indoor spaces of water-damaged housing in the Republic of Korea. We investigated the levels of airborne mold according to the characteristics of water damage types and explored the correlation between the distribution of mold genera and the characteristics of households. Samplings were performed from January 2016 to June 2018 in 97 housing units with water leakage or condensation, or a history of flooding, and in 61 general housing units in the metropolitan and Busan area, respectively. Airborne mold was collected on MEA (Malt extract agar) at flow rate of 100 L/min for 1 min. After collection, the samples were incubated at 25oC for 120 hours. The cultured samples were counted and corrected using a positive hole conversion table. The samples were then analyzed by single colony culture, DNA extraction, gene amplification, and sequencing. By type of housing, concentrations of airborne mold were highest in flooded housing, followed by water-leaked or highly condensed housings, and then general housing. In more than 50% of water-damaged housing, the level of airborne mold exceeded the guideline of Korea's Ministry of Environment (500 CFU/m3). Of particular concern was the fact that the I/O ratio of water-damaged housing was greater than 1, which could indicate that mold damage may occur indoors. The distribution patterns of the fungal species were as follows: Penicillium spp., Cladosporium spp. (14%), Aspergillus spp. (13%) and Alternaria spp. (3%), but significant differences of their levels in indoor spaces were not found. Our findings indicate that high levels of mold damage were found in housing with water damage, and Aspergillus flavus and Penicillium brevicompactum were more dominant in housing with high water activity. Comprehensive management of flooded or water-damaged housing is necessary to reduce fungal exposure.
        4,000원
        5.
        2013.12 KCI 등재 구독 인증기관 무료, 개인회원 유료
        An accident from machine work is often fatal to the worker. This accident is mostly preventable through perfect process jig. In case of this machine work, however, the disaster frequently occurred because of the design which is not considered the beginning of product design, post-process and mass process of production. As for sand casting method, this has the merits of the production; the product is easily produced by manual labor. On the other hand, this method has the demerits of a bigger dimensional error contrary to other mass process of production. When the sand casting product is in machine work, there are various problems such as unsafe fix and excessive cutting, product desorption and rapid life depreciation of equipment and tools. Considering the characteristics of sand casting method, it is accepted as difficulty to improve the problems. In this study, it suggests shell mold method for mold instead of the machine work after the sand casting of the circle shape container product. And the surface accomplishes the following average of surface roughness Ra9.94 ㎛ of machine work with the casting of flask mold by shell mold method. In accordance with the simplification of processing process and reducing the average thickness variation by mass production of product with detailed appearance, it has a good influence on safety accident prevention caused by production and damaged product. It is confirmed that making higher degree of size precision of all machine work product is possible to increase the safety and productivity, reduce the processing process and improve environment.
        4,000원
        6.
        2013.12 KCI 등재 구독 인증기관 무료, 개인회원 유료
        This study addresses the relationship between individual differences regarding self-concept, measured by Self Concept Clarity (SCC) scale and Relational-Interdependent Self-Construal and relationships (RISC) scale, and diverse affective consequences after choice behavior. We hypothesized that lower self-concept clarity and higher relational interdependence would be related to increased susceptibility to choice context–for example, how a choice set is constructed based on one’s initial preference. We examined how variations in a choice set can produce different affective consequences after making choices, and investigated the underlying neural mechanism using fMRI. In this experiment, participants first rated their preferences for art posters, and made a series of choices from a presented set. After the choice task, they completed post-choice measures including preferences for the chosen posters, as well as measures of their self-concept clarity and relational interdependence. Our behavioral results demonstrated that when participants faced more conflicting choice context, self-concept clarity was related to more positive affective consequences after choice, whereas relational interdependence was correlated with a lower second-rated attractiveness of the chosen option. The neuroimaging analysis of choice-making revealed that self-concept clarity and the degree of their relational interdependence served as modulators in shaping how one perceives and experiences the same decision-making process. These results have theoretical and practical importance in that it is one of the first studies investigating the influence of the individual differences regarding self-concept on value-based decision making process among diverse choice set contexts.
        4,300원
        7.
        2013.11 구독 인증기관 무료, 개인회원 유료
        기계가공으로 인한 사고는 작업자에게 치명적인 경우가 많다. 이러한 사고는 완벽한 가공지그을 통해 대부분 예방이 가능하지만 제품설계초기 후가공과 양산 공정은 고려되지 않고 설계되어 기계가공 시 재해로 연결되는 경우가 빈번히 발생하고 있다. 사형 주조법은 수작업으로 손쉽게 제품을 생산하는 장점을 가지는 반면 치수오차가 다른 양산공정 보다 크다는 단점을 가진다. 이런 사형 주조품을 기계 가공할 때 제품의 치수편차로 인해 불안전한 고정및 과다한 절삭, 제품이탈, 공구파손, 장비와 공구의 빠른 수명감소 등의 다양한 문제가 발생 하지만 사형주조의 특성상 개선하기 어려운 문제로 인식되고 있다. 본 연구에서는 원형의 용기형태의 제품을 사형주조 후 기계가공 하는 것을 금형으로 대체하기 위한 셸몰드법을 제시하고 셸몰드로 만든 셸주형으로 주조함으로서 표면조도 평균 Ra9.94㎛의 기계가공에 준하는 표면을 구현하였다. 외형의 정밀한 제품을 대량 생산하여 가공공정의 간소화 및 평균 두께 편차를 줄임으로서 제품파손 및 제작 시 발생할 수 있는 안전사고예방에 긍정적인 영향을 주었다. 기계가공전 제품의 치수정밀도를 높여 안전성, 생산성향상, 가공 공정단축, 환경개선 등을 이 가능함을 확인하였다.
        4,000원
        8.
        2008.09 KCI 등재 구독 인증기관 무료, 개인회원 유료
        Mycotoxins produced by molds isolated from discolored sun-dried red pepper fruits were determined and the toxicity to animals was also tested by feeding mold-grown unpolished rice to rats. Among the mold species tested, only Alternaria alternata was toxic to experimental animals, while other mold species belonging to the genera of Colletotrichum, Diaporthe, Diaporthopsis, Botryosphereia, Aspergillus and Fusarium were not. Rats fed Alternaria-grown rice lost weight and died within two weeks of feeding period. Succumbed rats during the process of feeding study showed extreme cases of enlargements of stomach, small intestine and liver. Among the 17 Alternaria isolates, 8 species produced considerable amount of tenuazonic acid along with small amounts of other toxins including alternariol and monomethyl ether derivative of alternariol in both red pepper homogenate and unpolished rice. It is therefore advised that red pepper fruits infested by molds during the sun-drying process be discarded to avoid unnoticeable health hazards.
        4,000원
        10.
        1999.09 KCI 등재 SCOPUS 구독 인증기관 무료, 개인회원 유료
        지르콘 쉘 몰드를 제조하여 소결 온도 및 시간에 따른 소결거동이 기계적특성에 미치는 영향을 관찰하였다. 1000˚C에서 1.5시간동안 소결 한 쉘 몰드의 1차 코팅 표면층에서 미세균열의 크기 및 수가 극대화되었으며 소결온도 및 시간이 증가할수록 상온강도와 기공의 비표면은 감소하였다. 1차 소결 후 1500˚C에서 4시간동안 소결 처리한 주형의 고온변형거동은 백업층과 하중의 역방향으로 스터코와 지르콘 슬러리의 경계면을 따라 변형이 발생하였다. 1차 코팅층에서 알루미나 스터코와 지르콘 슬러리의 열팽창계수 차이와 백업 코팅층에서 지르콘 슬러리간의 입도 차이가 고온변형시험 중 역변형을 일으킨 것으로 판단된다.
        4,000원
        11.
        1996.12 KCI 등재 SCOPUS 구독 인증기관 무료, 개인회원 유료
        고온용 세라믹 쉘 몰드를 용융 알루미나와 콜로이달 실리카를 사용하여 제조한 후, 세라믹 쉘 몰드의 강도에 영향을 주는 요인을 분석하였다. 세라믹 쉘 몰드의 강도는 바인더의 실리카 입자의 크기가 작을수록 크며 또한 실리카 농도에 비례하여 증가함을 보이며 저온에서의 강도 발현은 콜로이달 실리카의 필름 형성에 의한 입자들의 결합임을 알 수 있었다. 세라믹 쉘 몰드의 소성 강도는 부착 스타코의 크기가 작을수록 크며 소성 온도에 비례하여 증가함을 보였다. 고온에서의 강도 발현은 알루미나 입자와 콜로이달 실리카 바인더의 결합뿐만 아니라 알루미나 입자사이의 결합도 영향을 줌을 알 수 있었다. 쉘 몰드의 결정상은 1300˚C이하에서 소성한 경우 α-알루미나만 존재함을 보여 실리카는 비정질로 계속 남아 있음을 알 수 있고 1400˚C 이상에서 소성한 경우 뮬라이트가 생성됨을 보였다.
        4,000원
        12.
        1987.11 KCI 등재 구독 인증기관 무료, 개인회원 유료
        Effect of initial PH on the lipid accumulation and fatty acid composition of some species of mold were investigated. The maximum lipid content content produced by Aspergillus niger var. macrosporus was 17.5% at PH 3.5, by Aspergillus fumigatus 23.5% at PH 3.5 by Penicillium spinulosum 12.0% at PH 4.0 and by Penicillium notatum 7.3% at PH 4.0. The major fatty acids were palmitic, stearic, oleic and linoleic acid in all experimental molds. At PH from 4.5 to 6.0, the proportion of linoleic acid was increased and those of palmitic and oleic acid were decreased with rising in PH, therefore, degree of lipid unsaturation was increased in all experimental molds.
        3,000원
        13.
        1985.11 KCI 등재 구독 인증기관 무료, 개인회원 유료
        Influence of vitamins on the felt and lipid production of Aspergilus niger var. macrosporus, Aspergillus fumigatus and penicillium notatum were investigated after 10 days of incubation at 30℃ under static culture condition. The felt of molds were lower in the media containing vitamins than control medium. The lipids produced by each strains were highest yields in media containing vitamins. Among of these Aspergillus niger var. macrosporus and Aspergillus fumigatus produced. 4.6g and 5.28g in medium containing inositol 2.5mg/l and 0.5mg/l, respectively; while Penicillium notatum produced 1.51g in a medium containing thiamine 10mg/l. The major fatty acid of lipids were palmitic acid, stearic acid, oleic acid and linoleic acid. Aspergillus niger var. macrosporus was lower palmitic acid in media containing vitamins than control medium, While linoleic acid was higher in media containing thiamine and inositol. Aspergillus fumigatus was lower oleic acid in media containing vitamins than control medium, While linoleic acid was higher in media containing vitamins. Peniillium notatum was lower palmitic acid, oleic acid and stearic acid in media containing vitamins but linoleic acid was higher. The composition of fatty acid of lipids changed depending on the media containing vitamins but hardly found a certain tendency except linoleic acid which was higher in a media containing thiamines and inositols. The degree of unsaturation of fatty acids in the lipids were comparatively higher in media containing vitamins than control medium.
        4,000원
        14.
        1974.06 KCI 등재 구독 인증기관 무료, 개인회원 유료
        1. 쌀바구미류는 성충>유충>용의 순으로 체내에 곰팡이를 많이 갖고 있었다. 2. 무균소맥에서 사육하면서 체내 균류의 잔존상황을 조사한 바 10일후에는 완전히 제거할 수 있었고, 가장 오래 잔류하는 것은 A. candidus였다. 3. 곰팡이류의 산난수에 미치는 영향은 A. candidus 구가 가장 많았고 A. ruber 그리고 대조구의 순이고 A. niger구가 가장 적었다. 4. 유충의 생육은 A. candidus>A. ruber>대조구의 순으로 양호하였고 A. niger구에서는 2-3령까지 밖에 발육을 하지 못하였다. 5. 생육이 가장 빠른 것은 A. candidus구로 제3주에용화개체를 볼 수 있었고 제4편에 성충 우화를 볼 수 있었다. 대조구에서도 동일한 경향을 볼 수 있었으나 생육은 약간 늦었다. 6. A. niger구에서 생육이 불량한 것은 왕성한 균생장으로 쌀바구미의 활동이 저해되는 것과 동시에 불명의 원인이 있는 듯 하였다. 7. 저곡중의 쌀바구미와 곰팡이류간에는 진화과정을 통하여 원시적 협동작용이 있었다.
        4,000원