• 한국미생물·생명공학회지
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• 제27권3호
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• pp.230-235
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• 1999

This study was intended to develop a new rice product by the fermentation of saccharified rice solution using Bifidobacterium and to select an appropriate reducing agent to provide the anaerobic condition for the growth of Bifidobacterium during fermentation. The enhancement of the growth of Bifidobacterium in saccharified rice solution was achieved by the treatment of reducing agents such as ascorbic acid and cysteine. The physical and chemical properties of the fermented product were evaluated, and the effect of the reducing agents were compared between ascorbic acid and cysteine. The fermented product with the addition of ascorbic acid shows the lower pH and the higher titratable acidity comparing the product with the addition of cysteine. This indicated that ascorbic acid was more appropriate reducing agent than cysteine for the fermentation of the saccharified rice solution. The number of viable Bifidobacterium in the fermented product with the addition of ascorbic acid(2.2$\times$108~3.4$\times$108CFU/ml) was greater than that with the addition of cysteine (8$\times$107~2.8$\times$108CFU/ml). Ascorbic acid supplement also contributed better sensory properties, such as flavor, taste and overall acceptibility than cysteine supplement did.

• 한국건축시공학회:학술대회논문집
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• 한국건축시공학회 2013년도 추계 학술논문 발표대회
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• pp.66-67
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• 2013

Replacing a large amount of ground granulated blast furnace slag is limited because early age strength is low due to latent hydraulic property despite excellence of long-term strength. This study aimed to examine produceableness of high-activated ground granulated blast furnace slag using slag by-product from steel process. As experimental variable, the properties of strength development were analyzed by setting fineness and replacement ratio of slag by-product, curing conditions, and W/B. The results of study showed that high-activated ground granulated blast furnace slag using slag by-product as an activator improve the compressive strength of mortar. It is expected to be used as binder for secondary product of concrete considering curing and mixing conditions because high-activated ground granulated blast furnace slag can be hydrated by itself.

• Journal of Astronomy and Space Sciences
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• 제27권4호
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• pp.353-357
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• 2010

In general, the information of inertia properties is required to control a spacecraft. The inertia properties are changed by some activities such as consumption of propellant, deployment of solar panel, sloshing, etc. Extensive estimation methods have been investigated to obtain the precise inertia properties. The gyro-based attitude data including noise and bias needs to be compensated for improvement of attitude control accuracy. A modified estimation method based on the law of conservation of angular momentum is suggested to avoid inconvenience like filtering process for noise-effect compensation. The conventional method is modified and beforehand estimated moment of inertia is applied to improve estimation efficiency of product of inertia. The performance of the suggested method has been verified for the case of STSAT-3, Korea Science Technology Satellite.

• 한국소성가공학회:학술대회논문집
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• 한국소성가공학회 2002년도 춘계학술대회 논문집
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• pp.21-24
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• 2002

One of the factors influences on microstructure of semi-solid product is forging pressure. Generally, the more forging pressure makes the more fine microstructure in semi-solid compression test. The microstructure and mechanical properties were investigated according to the forging pressure. The applied pressure is 110MPa, 140MPa and 170MPa, respectively. Heat treatment conditions also influence to the microstructure and mechanical properties of semi-solid product. T6 heat treatment was performed and the evaluation of microstructure and mechanical properties was investigated according to the aging time in T6 heat treatment.

• Journal of applied mathematics & informatics
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• 제42권3호
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• pp.583-605
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• 2024

This paper discusses the properties of attractors of Type 1 IFS which construct self similar fractals on product spaces. General results like continuity theorem and Collage theorem for Type 1 IFS are established. An algebraic equivalent condition for the open set condition is studied to characterize the points outside a feasible open set. Connectedness properties of Type 1 IFS are mainly discussed. Equivalence condition for connectedness, arc wise connectedness and locally connectedness of a Type 1 IFS is established. A relation connecting separation properties and topological properties of Type 1 IFS attractors is studied using a generalized address system in product spaces. A construction of 3D fractal images is proposed as an application of the Type 1 IFS theory.

• 한국축산식품학회지
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• 제37권5호
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• pp.708-715
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• 2017

The acid pretreatment of collagen molecules disrupts their crosslinks and assists in the release of acid-soluble proteins, fats, and other components. Generally, to achieve optimum extraction efficiency, strong acids may be used at a lower acid concentration compared to weak acids. This study aimed to determine the yield and physicochemical properties of gelatins extracted from buffalo hides pretreated with different acids. Hides were extracted with hydrochloric, citric, and acetic acids at concentrations of 0.3, 0.6, 0.9, 1.2, and 1.5 M. A completely randomized design and the least significant difference test were used in the experimental design, and all measurements were performed in triplicate. The highest yield (29.17%) was obtained from pretreatment with 0.9 M HCl. The gel strength did not differ significantly (p>0.05) according to acid type (280.26-259.62 g Bloom), and the highest viscosity was obtained from the 0.6 M citric acid pretreatment. All the gelatins contained ${\alpha}$- and ${\beta}$-chain components and several degraded peptides (24-66 kDa). The color and Fourier-transform infrared spectrum of the gelatin extracted using 0.9 M HCl were similar to those of commercial bovine skin gelatin. In general, the physicochemical properties of the gelatin complied with the industry standard set by the Gelatin Manufacturers Institute of America, revealing that buffalo hide could serve as a potential alternative source of gelatin.

• 대한기계학회논문집A
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• 제39권8호
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• pp.773-780
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• 2015

적층조형(additive manufacturing, AM)은 액체, 고체 상태인 폴리머, 금속 등의 재료를 층층이 쌓아서 3 차원 형상을 제조하는 기술이다. AM 기술은 제품 개발 초기단계에서 시제품 제작에 주로 사용되었으나, 최근 들어 이를 실제 제품제작에 적용하는 것에 대한 관심이 높아지고 있다. 한편 AM 기술에서 적층방향은 최종성형품의 기계적 물성에 영향을 줄 수 있다. 따라서 본 연구에서는 폴리머 재료를 사용하는 대표적인 AM 기술인 FDM, PolyJet 그리고 SLA 방식으로 제작되는 재료의 기계적 물성을 실험을 통해 파악하여 보았다. 이때 시험편의 형상은 ASTM D 638 을 참고하였고 적층방향을 달리하여 성형하였다. 시험편의 인장시험으로부터 얻은 응력-변형률 선도를 바탕으로 기계적 물성을 조사하였다. 또한 시험편의 파단부를 SEM 촬영하여 물성차이의 결과를 분석하였다.

• Journal of the Korean Wood Science and Technology
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• 제50권6호
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• pp.392-403
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• 2022

Currently, composite board manufacturing using natural fibers has the potential to expand owing to environmental awareness. To produce a composite board, treatment is required to improve the mechanical and physical properties of the natural fibers. In this study, sodium chloride (NaCl) was used for the chemical treatment. However, studies on chemical treatments using NaCl are limited. This study aimed to investigate the characteristics of kenaf fibers after NaCl treatment. The NaCl treatment concentrations were 1, 3, and 5 wt.% at room temperature, with soaking durations of 1, 2, and 3 h. The tensile strength, strain, and Young's modulus were measured to evaluate the mechanical properties of the fibers. The fiber bundle diameter, weight change owing to treatment, and contact angle were determined to analyze the effect of NaCl treatment. The kenaf fiber bundle treated with 5 wt.% NaCl for 3 h exhibited the highest tensile strength, Young's modulus, reduction in fiber bundle diameter, weight change, and decrease in contact angle compared to those of untreated fiber bundles. The tensile properties of the fiber bundle exhibited a tendency to decrease with increasing fiber bundle diameter. Increasing the soaking duration from 1 to 2 h did not result in a significant decrease in the fiber bundle diameter or an increase in tensile strength. However, a further increase in the soaking duration from 2 to 3 h resulted in a considerable decrease in the fiber bundle diameter and an increase in the tensile strength.

• 대한수학회보
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• 제51권3호
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• pp.863-881
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• 2014

Many differential geometric properties of a submanifold of a Kaehler manifold are conceived via canonical structure tensors T and F on the submanifold. For instance, a CR-submanifold of a Kaehler manifold is a CR-product if and only if T is parallel on the submanifold (c.f. [2]). Warped product submanifolds are generalized version of CR-product submanifolds. Therefore, it is natural to see how the non-triviality of the covariant derivatives of T and F gives rise to warped product submanifolds. In the present article, we have worked out characterizations in terms of T and F under which a contact CR- submanifold of a Kenmotsu manifold reduces to a warped product submanifold.

• 한국정밀공학회:학술대회논문집
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• 한국정밀공학회 1997년도 추계학술대회 논문집
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• pp.115-120
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• 1997

Environmental Product Life Cycle Management is an activity for defining and describing the product, process or activity environmentally. Especially, the main responsibility for the environmental impact of products lies in the design phase of product. Designers cany a heavy responsibility to determine technical, economic and ecological properties of the product. So in order to help designers, structured understanding and application of treating large amount of data and infonnation should be considered. This paper presents a methodological approach for decision supporting to build Product Life Cycle Management system and show a set of database modeling. Additionally, a key issue for databases is the quality of the provided information.