• 전기의세계
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• 제19권4호
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• pp.12-17
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• 1970

BaO.nFe$_{2}$O$_{3}$ Powder ferrite magnet was made by sintering process. The purity of the powder were 99.6% far BaO. 99.5% for Fe$_{2}$O$_{3}$, and the grain size 1-3 micron. The Optimum mixing ratio n=4.4 the optimum density 4.8gr/cm$^{3}$ and the optimum second sintering temperature 1260.deg. C was found. The theoretical bloch wall, dimension of domain and energy per unit volume of BaFe$_{12}$O$_{19}$ were compared with pure Fe. Also, the saturation magnetization and maximum energy product were computed.d.d.

• 펄프종이기술
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• 제31권4호
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• pp.69-75
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• 1999

This study was performed to investigated the application of mixed resins for corrugated container board. The corrugated container board yields a sandwich structure in which a linerboard material is glued to a corrugated medium . Now, manufacturing corrugated container boards don't provide sufficient strength, and result in box failure during shipping . Therefore improvement of box strength is necessary . In this study, we intend to improve box strength by improving corrugated medium strength with mixed resins and to find the optimum treatment condition of this resins. First, we tried to mixed resins as Starch+CMC, Starch_Irea, CMC+Urea, Second, investigated to applicability of this resins for corrugated medium , and the third, measured tensile index, burst index, and edgewise compression index on liner, medium paper, and single faced corrugated container board. In this test results, we obtained that the improvement ratios of tensile index in liner and medium paper were approximately 80-185%, 60-118% , respectively. The respecting improvement ratios of edgewise compression index of single faced corrugated container board was approximately 91-124%, relatively. In addition, we concluded that optimum condition in mixing ratio was 1 :3 with CMC + Urea and the ap[plication amounts was 9% on materials. Fro manufacture of corrugated container board, optimum condition in mixing ratio was 1 : 3 with 5% CMC +Urea , because of considering to improvement of strength on cost.

• 한국식생활문화학회지
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• 제19권2호
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• pp.193-199
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• 2004

The purpose of this study was to determine the organoleptic charateristics of cauliflower pickles made in various compounding ratio according to central conposite design for optimum organoleptic characteristics of the cauliflower pickles. The optimum mixing condition of cauliflower pickles were optimized, using central composite design with 3 variables and 3 levels, by response surface methodology. The various kinds of cauliflower pickle were made in various compounding ratio of vinegar, salt and sucrose - critical ingredients of pickle recipe - and were presented to reliable panels, who graded the subjects in 7 degrees for 4 items : color, flavor, hardness and overall quality. The optimum mixing conditions of cauliflower pickle were 603.50g of vinegar, 80.13g of salt and 251.07g of sucrose in the maximum point of overall quality.

• 동아시아식생활학회지
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• 제4권3호
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• pp.147-169
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• 1994

This study was conducted to ivestigate the quality of modeled chinese-cabbage Kimchi. The mutual action of sub-ingredients and optimum mixing conditions were examined by analyses of pH, acidity, content of vitamins, carotenes, number of total microorganism, and Lactobacilli, the activities of softening related to enzymes (polygalacturonase and ${\beta}$-galactosidase), and sensory quality during fermentation. The result about the mutual action of red pepler powder and garlic showed that the pH was decresed as concentration of garlic was higher and that of red peppler powder became lower. Kimchi had unpleasant taste and undesirable odor when the adding ratio of the peper powder and garlic was unbalanced. As the concentration of garlic became higher, the content of vitamin C in Kimchi tissue decreased while that of vitamin C in Kimchi juice increased. The contents of vitamin B1, B2 and carotene increased as the concentration of garlic became lower. The optimum mixing ratio of red pepper powder and garlic evaluated by overall eating quality was 4.66% and 3.45%, respectively. The result about the mutual action of ginger and green onion was that pH became higher as the concentration of ginger was 1.84% and that of green onion was 5.96%. The intensity of fresh taste and odor became stronger as the concentration of ginger increaed to 2.76% and that of green onion decreased to 2.98%. The balance of sour, salty and hot taste became better as the concentration of ginger increased and that of green onion decreased. The optimum mixing condition evaluated by overall eating quality was 2.94% in ginger ＋ 2.78% in green onion. The contents of vitamin B1, B2 and C were high in this condition. The result about the mutual action of leek and salted anchovy juice was that pH became lower as the concentration of leek increased and that of salted anchovy juice decreased. Sour, hot and sweet tastes were good in the condition of leek 12%, salted anchovy juice 4.69%. Palatable, fresh taste and odor became weaker when the one of both sub-ingredients was too much little. The optimum mixing condition evaluated by overall easting quality was 9.76% in leek ＋ 7.32% in salted anchovy juice. The contents of vitamin B1, B2, C and carotene were high in this condition and other sensory qualities were good. The result about the mutual action of salt and sugar was that pH became lower as the concentration of sugar became higher and that of salt became lower. The sweet taste was reduced of hot taste than salty taste. Palatable and fresh tastes were desirable when Kimchi fermented with less salt and more sugar. The optimum mixing condition evaluated by overall eating quality was 3.29% in sugar ＋ 4.80% in salt. The contents of vitamin B1, B1, C and carotene were high in this condition. The result of model Kimchi fermented at 20$^{\circ}C$ was that the number of Lactobacilli in model Kimchi was higher than that of in control Kimchi. The fermentation period was extended under pH 4.0 and the contents of vitamin B1, B1,C and carotene were high through the whole edible period. The activity of polygalacturonase was low, but that of ${\beta}$-galactosidase was high during fermentation.

• Journal of Biosystems Engineering
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• 제28권5호
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• pp.411-420
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• 2003

Physical and cultural properties were investigated on the rice-seed pellets made by the pelleting machine(Yu, 2003) as the changes with mixing ratios of soil to rice seed of 6 : 1, 7 : 1, and 8 : I, and rotating speeds of forming rolls of 7, 10, and 13 rpm. Average weight, average diameter, and average sphericity of the pellets were 1.70 g, 12.0 ㎜, and 99.1 ％, respectively. Average number of seeds per pellet was more than 3, and almost all pellets had more than 3 seeds in the cases of mixing ratios of 6 : 1, and 7 : 1 at the forming rolls' speed of 7 rpm. Gradual drying was needed because rapid drying caused cracks on surface of the pellets. Compression strength of the pellets dried in shady room was in the range of 132 ∼ 152 N, which was enough for handling. Comparing with the previous pellets(Park, 2002), average number of seeds per pellet, ratio of pellets including more than 3 seeds, and compression strength increased due to the effects of pressure feed of pellet materials, and improvements of the forming rolls. Emergence ratio of the pellets made at the mixing ratio of 6 : 1 and the forming rolls' speed of 7 rpm, was 100 % on dry paddy and was 97 % on flooded paddy surface. Good growth characteristics, and yield except number of seedling stand and ratio of missing plant were shown in planting of the pellets made at the mixing ratio of 7 : 1 and the forming rolls' speed of 7 rpm on flooded paddy surface field. Considering the cultural results, the mixing ratio of 6 : 1, and the forming rolls' speed of 7 rpm seems to be optimum operating condition for the improved pelleting machine.

• 한국지반환경공학회 논문집
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• 제25권6호
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• pp.5-12
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• 2024

현재 저수지 제체의 차수성 및 안전성 확보를 위해 약액을 저압으로 주입하여 제체 손상을 최소화하는 그라우팅 공법이 보편적으로 사용되고 있으나, 내구성 확보와 체계적인 고화재의 배합비 결정방법이 정립되어 있지 않은 문제들이 있다. 본 연구에서는 원지반과 고화재를 다양한 중량비율로 교반·혼합하였을 경우 혼합체의 투수계수와 강도를 실내시험을 통해 확인하였으며, 시험결과들의 분석을 통해 최적 배합비를 제안하였다. 실내실험을 위한 공시체는 고화재의 배합량을 고려하여 제작하였다. 투수시험용 공시체는 사질토와 점성토 별 고화재 배합량 1.5kN/m³에 대해 제작하였으며, 투수시험 결과 차수 성능이 확보되어 각종 설계기준을 만족하는 것을 확인하였다. 강도시험을 위한 공시체는 점성토의 경우 5가지, 사질토는 3가지 배합비로 각각 3개 총 24개의 시편을 제작하였으며, 시험 결과 사질토와 점성토 모두 배합량 2.0kN/m³ 이하에서는 일축압축강도가 재령일이 증가함에 따라 선형적으로 증가하는 경향을 나타냈다. 따라서 현장에 적용되는 최적의 배합비는 고화재 배합량을 1.5kN/m³ 및 2.0kN/m³으로 결정하였다. 또한 현재 운영 중인 노후 저수지 개보수사업 설계사례를 대상으로 실험성과를 반영한 수치해석을 실시한 결과 저수지 제체의 차수 및 안전성 증대 효과를 확인하였다.

• 한국지반공학회:학술대회논문집
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• 한국지반공학회 1999년도 연약지반처리위원회 학술세미나
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• pp.84-95
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• 1999

Laboratory experiments were performed to evaluate the strength characteristics of solidified sandy soils by portland cement with mixing conditions. Factors considered in the experiments were the fine content(<#200, %), cement content(%) and water-cement ratio and unconfined compressive strength tests were performed on samples at 7 and 28 cured day. Results of tests showed that for a low cement content(7%∼10%) the fine content was very important while for a high cement content the water-cement ratio was very important. For 7%∼10% cement content, the optimum fine content which gained maximum strength was about 30%. But for 13% cement content, low fine content and water-cement ratio were more useful than others. In the multi regression analysis, significant equation was gained.

• 한국콘크리트학회:학술대회논문집
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• 한국콘크리트학회 1996년도 가을 학술발표회 논문집
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• pp.283-289
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• 1996

In this paper, the mix design of the super flowing concrete is described with respcet to basic concept, confined water ratio($\beta_p$), volume ratio of water-binder(w/b), volume ratio of fine aggregates($S_r$) and coarse aggregates($G_v$). The primary purposes of this study are to evaluate the effects of cementitious materials(fly ash, slag cement, portland cement), mixing factors ($\beta_p$, w/b, $S_r$, $G_v$)., and to propose the mix design method of the super flowing concrete. As results of this study, confined water ratio($\beta_p$) of cementitious materials is very high (0.99~1.1), and then the ranges of the optimum mixing factors to be satisfied with the super flowing concrete are $S_r$ 47$\ell$ 2%, $G_v$ 52$\ell$ 1%.

• 한국물환경학회지
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• 제26권2호
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• pp.225-230
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• 2010

Dumping of waste sludge to ocean will be prohibited in Jananuary, 2012. Thus, various methods of sludge recycling are intensively studied. To present new way of sewage sludge recycling method, feasibility of making porous biological support media was investigated. Porous biological support media was made of sludge cake from sewage treatment plant and loess. They were mixed in varying ratio and burnt in high temperature to ensure sufficient mechanical strength. It was evaluated that about 67% of sewage sludge were ignitible. The ignitible portion play an important role in making pore in biomedia during ignition process. It was evaluated that optimum mixing ratio of loess to sludge cake was 25% in respect of compressive strength. In results of observation using scanning electron microscope (SEM), inner structure of biomedia become simple when the contents of loess are increased.

• 한국콘크리트학회:학술대회논문집
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• 한국콘크리트학회 2008년도 추계 학술발표회 제20권2호
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• pp.593-596
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• 2008

콘크리트의 블리딩은 재료분리의 일종으로서 콘크리트 품질뿐만 아니라 내구성을 저하시키는 원인으로 작용한다. 본 연구에서는 콘크리트 블리딩에 영향을 미칠 것으로 예상되는 시멘트 및 믹싱시간의 두 요인의 변화에 따른 특성을 파악하여 블리딩 제어기술 확보를 위한 기초자료를 제공하고자 한다.연구결과에 의하면, 믹싱시간이 증가할수록 블리딩율도 증가하는 추세를 나타내고 있었다. 블리딩양(믹싱시간 90초)은 시멘트 특성에 의한 차이가 뚜렷하게 나타나고 있었으며, 콘크리트 특성값(블리딩율, 슬럼프 및 재령 3일 압축강도)은 믹싱시간과 비례적인 관계가 있었다. 또한, 슬럼프 손실율과 믹싱시간은 반비례적인 관계가 존재하였고, 압축강도값은 초기재령에서만 믹싱시간에 의한 영향을받고 있었다.향후, 최적 믹싱시간 도출을 위한 다양한 검토가 필요할 것으로 판단된다.