• 한국패류학회지
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• 제26권1호
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• pp.1-18
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• 2010

자연에 존재하는 생명체들은 유기-무기 성분들이 포함된 미세구조로 이루어진 계층학적으로 복잡한유-무기 나노 복합재를 합성한다. 자연에서 진행되는 유기-무기 나노복합재의 생성 및 재생 과정은 생광물화과정으로서 생물학적 환경에서 진행되는 생광물화과정의 연구는 신물질 합성에 대한 단서를 제공할 뿐만 아니라 산업적으로 중요한공정의 개발에 있어 귀중한 지침으로 활용될 수 있다. 연체동물 역시 생광물화과정을 수행하는 다른 생명체들과 마찬가지로 단백질과 다당류로 이루이진 유기매트릭스와 무기물의 상호작용을 통하여 패각을 설계하고 합성한다. 본 고찰에서는 이매패류의 패각 형성 과정 연구를 기반으로 아울러 생광물화과정 연구를 기반으로 한 소재합성과 관련된 생체모방공학 기술을 고찰하였다.

• 자원리싸이클링
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• 제15권2호
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• pp.32-36
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• 2006

마그네슘은 자동차 엔진 경량화재료 및 휴대폰과 노트북 PC케이스 등 기능성 경량재료로서의 용도개발과 함께 수요가 증가하고 있다. 마그네슘 제련법은 원료광의 특성에 따라 달라지는데 크게 용융염전해법과 열환원법 두가지로 구분할 수 있다. 본 연구에서는 염화마그네슘을 사용하여 용융염전해법에 의해 전해 마그네슘을 얻고자 하였다. 흑연양극의 침지깊이를 일정하게 하고 전해전압 7V로 두가지 조성의 염욕을 비교 실험하였다. $760^{\circ}C$에서 전해 실험한 결과 $KCl/NaCl/MgCl_2$ 혼합염욕이 $KCl/NaCl/CaCl_2/CaF_2/MgCl_2$ 혼합염욕보다 전류효율 면에서 더 효과적이었다. 회수된 전해 마그네슘의 순도는 98% 이상이었다. 본 연구를 통하여 용융염 전해장치를 Scale-up 하거나 상용화시 장치설계 등에 필요한 기초자료들을 축적할 수 있었다.

• Korean Chemical Engineering Research
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• 제48권2호
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• pp.205-211
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• 2010

상 하수 응집제인 폴리염화알루미늄(polyaluminumchloride, PAC)과 가성소다(NaOH)를 이용하여 수산화알루미늄을 합성하고, 가성소다(NaOH) 첨가량 변화에 따른 합성물 특징을 고찰하였다. 이 때 합성된 수산화알루미늄의 특징을 XRD, SEM, PSA로 분석하였다. XRD 분석 결과, NaOH 15g에서는 비정질 수산화알루미늄로, NaOH 20g에서는 깁사이트(gibbsite)(37%), 바이어라이트(bayerite)(35%), 보헤마이트(boehmite)(28%)의 혼합상(mixed phase)으로 나타났으며, NaOH 25g에서는 깁사이트(gibbsite)(67%), 바이어라이트(bayerite)(33%)로, NaOH 30g에서는 깁사이트(gibbsite) (83%), 바이어라이트(bayerite)(17%)로 나타났다. SEM 분석 결과, NaOH 25, 30g에서 판형 형태로 분석되었다. PSA 분석 결과, 수산화알루미늄의 입자 크기는 NaOH 첨가량이 증가할수록 감소하였다.

• 한국콘크리트학회:학술대회논문집
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• 한국콘크리트학회 2002년도 가을 학술발표회 논문집
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• pp.527-530
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• 2002

In the present study, immersion test using artificial seawater was performed to evaluate the resistance of mortar specimens with or without ground granulated blast-furnace slag (SG) and fly ash (FA). Another variable was the fineness levels of SG (4,450, 6,000 and 8,000 ㎠/g). From the results of the immersion test for 270 days of exposure, the excellent resistance to seawater attack for SG mortar mixtures, especially in a high fineness levels, was confirmed. However, the reductions in compressive strength of FA mortar specimens was similar to those of OPC mortar specimens irrespective of replacement of FA.. In order to understand the deterioration mechanism due to seawater attack, X-ray diffraction (XRD) analysis were also carried out. Some reactants such as ettringite, gypsum, brucite and Friedel's salt were possibly detected through XRD technique.

• KSBB Journal
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• 제13권5호
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• pp.615-620
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• 1998

The readily fermentable carbon sources in swine were acetic acid, propionic acid and butyric acid at the average concentrations of 7.2 g/L, 2.2 g/L and 2.7 g/L, respectively. The swine waste also contained excess nitrogen and other mineral sources. In shake flask experiments, the optimal range of cell growth for Azotobacter vinelandii UWD were 1.0∼3.5 g/L of acetic acid, 0.7∼2.0 g/L of propionic acid and 0.5∼2.0 g/L of butyric acid. A mixture of these three acids simulating two times diluted swine waste supported the best cell growth but the amount of carbon sources was limited. In shake flask and fermentor experiments, an addition of 30 g/L of glucose increased the final cell dry weight 8 times while the final poly (3-hydroxybutyrate-co-3-hydroxyvalerate) (PHBV) concentration increased 86 times compared with using acid mixture only. A. vinelandii UWD preferred organic acids in the sequence of acetic acid, propionic acid, butyric acid, and valeric acid.

• 한국콘크리트학회:학술대회논문집
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• 한국콘크리트학회 2002년도 봄 학술발표회 논문집
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• pp.545-550
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• 2002

Concrete is one of the essential structural materials in the construction. But, concrete consists of many materials and is affected by many factors such as properties of materials, site environmental situations, and skill of constructor. Therefore, concrete mixes depend on experiences of experts. However, it is more and more difficult to determine concrete mixes design by empirical means because more ingredients like mineral and chemical admixtures are included. Artificial Neural Networks(ANN) are a mimic models of human brain to solve a complex nonlinear problem. They are powerful pattern recognizers and classifiers, also their computing abilities have been proven in the fields of prediction, estimation and pattern recognition. Here, among them, the back propagation network and radial basis function network are used. Compositions of high-performance concrete mixes are eight components(water, cement, fine aggregate, coarse aggregate, fly ash, silica fume, superplasticizer and air-entrainer). Compressive strength and slump are measured. The results show that neural networks are proper tools to minimize the uncertainties of the design of concrete mixtures.

• 한국독성학회:학술대회논문집
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• 한국독성학회 2001년도 International Symposium on Signal transduction in Toxicology
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• pp.134-134
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• 2001

Cutting oils are complex mixtures of hydrocarbons, comprising of certain fractions of mineral oil, which are being frequently used as lubricating and heat transferring agents in various machine and tool industries. We investigated an acute and 2 weeks repeated irritation studies of two cutting oils (Cimperial 1010 as water-soluble cutting oil, and MSN 120 as insoluble cutting oil) using guinea pigs.(omitted)

• 한국콘크리트학회:학술대회논문집
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• 한국콘크리트학회 2006년도 춘계 학술발표회 논문집(II)
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• pp.53-56
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• 2006

To develop more durable concrete deck, performance characteristic test of HPC(High Performance Concrete) mixtures was carried out. The parameters used in this project were ; the mineral admixture details were 4 types such as ordinary portland cement(OPC), 20% fly ash (FA), 20% fly ash and 4% silica fume(FS), and 40% ground granulated blast-furnace slag(BS). Their design compressive strengths were 27MPa and 35MPa respectively. The results showed the compressive strength of concrete did not much affect the durability of concrete. HPC with blast-furnace slag(BS) showed the good durability but was prone to crack. HPC with fly ash(FA) or with fly ash and silica fume(FS) had the good durability and crack resistance.

• 한국콘크리트학회:학술대회논문집
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• 한국콘크리트학회 2003년도 가을 학술발표회 논문집
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• pp.74-77
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• 2003

This paper investigated the apparent chloride diffusivity of various concretes. Ten mixtures of concrete were initially prepared and tested to estimate diffusion property. The penetration depth and concentration of chloride ion were examined at the same water-binder ration. The binders were composed of normal portland cement, fly ash, ground granulated blast-furnace slag, and silica fume. From the results, it was concluded that using the mineral admixtures had a filling effect on the pore structure of cements matrix due to those pozzoanic reaction with the hydrates of cement, which increases the tortuosity of pore and makes large pore finer. And diffusivity of chloride is following: NPC100 > F10N90 > F30N70 > F20N80 > F20S05 > G30N70 > F10S05 > G30S05 > G30F15 > G50N50.

• 대한기계학회:학술대회논문집
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• 대한기계학회 2000년도 춘계학술대회논문집B
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• pp.90-95
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• 2000

Condensation heat transfer experiments for R-22 and R-407C refrigerants mixed with mineral oil and POE oil respectively were performed in straight and U-bend sections of a microfin tube. Experimental parameters were an oil concentration from 0 to 5%, a mass flux from 100 to $400 kg/m^2s$ and an inlet quality from 0.5 to 0.9. The enhancement factors for R-22 and R-407C refrigerants at the first straight section decreased continuously as the oil concentration increased. They decreased rapidly as the mass flux decreased and inlet quality increased. The heat transfer coefficients in the U-bend were the maximum at the $90^{\circ}$ position. The heat transfer coefficients at the second straight section within the dimensionless length of 48 were larger by a maximum of 33% than the average heat transfer coefficients at the first straight section.