• Korean journal of food and cookery science
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• v.15 no.3
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• pp.203-209
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• 1999

The effect of several hydrocolloids on the rheological behavior of wheat flour was investigated. The influence of the selected hydrocolloids (alginate, carrageenan, CMC, guar, locustbean and xanthan) on wheat flour was tested by using two different techniques; amylograph and texture analyzer. In order to have a general overview of their effects hydrocolloids were chosen from different sources implying a broad diversity of chemical structures. The hydrocolloid addition decreased the brightness(L) but increased yellowness(b). The interaction between hydrocolloid and flour produces a slight modification of the amylogram parameters, being the most clearly affected parameter breakdown, which is increased by carrageenan, guar and xanthan. Hardness and cutting force were augmented by hydrocolloid addition, while springeness was decreased except guar and locustbean. In summary, when looking for the improvement of the noodle texture, guar, locustbean are the best candidate additives due to their effects on pasting and texture properties. These hydrocolloids increase the hardness, cutting force, gumness, chew-ness, so were thought to increase the eating quality. So, each tested hydrocolloid affected in a different way the rheological properties of wheat flour, the results obtained are important for the appropriate use of these hydrocolloid as ingredients in the noodle making process.

• Journal of the Korean Society of Food Science and Nutrition
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• v.21 no.3
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• pp.279-285
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• 1992

Cytidine deaminase (EC 3.5.4.5) from Aspergillus fumigatus IFO 5840, which was the first cytidine deaminase to be found in a mold, was fractionated with ammonium sulfate (35-60%). When the enzyme solution in 0.25M of Tris-HCI buffer (pH 7.2) was preincubated at $37^{\circ}C$ for 25min, the enzyme activity was reached to maximum state. The optimum pH and temperature for the enzyme activity were found to be 6.8 to 7.2 and near $37^{\circ}C$, respectively. The enzyme was stable in a pH 7.2 to 9.0, and was generally stable at 4$0^{\circ}C$, but after treating at 6$0^{\circ}C$ for 20min at the optimal pH, 17% of the enzyme activity was inactivated, and disappeared completely by treating at 1$0^{\circ}C$ for 25min. Activation energy (Ea) of fungal cytidine deaminase was calculated as 14.190 Kcal /mol by the Arrhenius plot, and temperate coeffient ($Q_{10}$ ) of the enzyme was calculated as 2.163.

• Journal of the Korean Magnetics Society
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• v.9 no.1
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• pp.1-6
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• 1999

The crystallographic and magnetic properties of the ferrimagnetic $CoFe_{1.9}Ga_{0.1}O_4$ have been studied by X-ray, M$\"{o}$ssbauer measurements. The crystal structure is found to be inverse spinel structure with the lattice constant $a_0=8.386{\pm}0.005{\AA}$. M$\"{o}$ssbauer spectra of $CoFe_{1.9}Ga_{0.1}O_4$ have been taken at various temperatures ranging from 13 to 840 K. The isomer shifts indicate that the valence states of the Fe ions for tetrahedral (A) and octahedral (B) sites have ferric character. Debye temperatures for the A and B sites are found to be 882$\pm$5 K and 209$\pm$5 K, respectively. Atomic migration form the A to the B sites starts near 350 K and increases rapidly with increasing temperature to such a degree that 73% of the ferric ions at the A sites have moved over to the B sites by 700 K. by 700 K.

• Korean Journal of Materials Research
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• v.7 no.7
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• pp.618-622
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• 1997

상온에서 측정한 Cd$_{x}$Ni$_{1-x}$Fe$_{2}$O$_{4}$의 Mossbauer 스펙트럼은 조성비에 따라 x값이 0.4이하인 시료에서는 준강자성에 의한 여섯개의 공명 흡수선, x값이 0.5인 시료에서는 이완된 형태의 공명흡수선, 그리고 x값이 0.6시료인 상자성에 의한 두개의 공명 흡수선이 나타났다. Cd$_{x}$Ni$_{1-x}$Fe$_{2}$O$_{4}$의 x값이 0.4이하인 시료의 초미세 자기장(H$_{hf}$)과 x값이 0.6 이상인 시료의 사중극자 분열치 (Q.S.)는 Cd농도가 증가함에 따라 감소한다. 시료의자기적 성질에 따른 이성질체 이동치(I.S.)의 차이는 있으나, Ni와 Cd이온의 농도에 따른 뚜렷한 의존성은 나타나지 않았다.다.

• Applied Biological Chemistry
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• v.10
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• pp.23-31
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• 1968

We have obtained the following results, at the production of cellulase of Chaetomium globosum and its properties of crude enzyme. 1. At the production of enzyme, wheat bran solid culture was more active than surface or shaking culture. 2. The production of enzyme was maximum between the eighth and the tenth days, but slightly decreased thereafter. 3. The optimum condition of the reactions in saccharification with CMC were obtained the following results. 1) The optimum pH was within the range of from 4.0 to 5.0 and stable pH range was within 3.5 to 6.5. 2) The optimum temperature was $40^{\circ}C$ and thermal stability was below $50^{\circ}C$ and completely inactivated at $70^{\circ}C$ 4 Dialyzed crude enzyme was activated by $Mn^{++}\;Mg^{++}\;Fe^{++}\;and\;Mo^{++}\;respectively\;but\;Hg^{++}$ was inhibited its enzyme action.

• Korean Journal of Materials Research
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• v.6 no.9
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• pp.905-918
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• 1996

초전도 마그네트 구조용 부재로 최근 개발된 오스테나이트계 스테인레스강 JN1 모재, GTA 용접부 및 열처리재에 대한 기계적 성질을 조사하기 위해 실온(293K)에서 극저온(4K)까지의 온도에서 소형펀치(Small Punch)시험을 실시하였다. GTA 용접부의 용융선 근방의 극저온 기계적 성질은 모재와 용접금속에 비해 크게 저하하였다. 4K에서 실험된 용융선 시험편으로 얻어진 하중-변위곡선상에서 부하의 초기 단계에 보통의 서레이션과 다른 pop-in이 관찰되었고, 이때 시험편 표면의 용융선 근처에서 약 0.1-1mm 정도의 크랙이 발생하였다. 열처리재의 기계적 성질은 열처리 시간과 온도의 증가 또는 시험온도의 저하에 따라 크게 저하되었다. 위의 결과에 기초하여 본 연구에서 실시한 소형 시험편을 사용하는 SP 시험법은 극저온에서 JN1 강의 모재와 열처리재뿐 만 아니라 GTA 용접부의 기계적 성질을 평가할 수 있는 유용한 시험법이었다.

• Proceedings of the Materials Research Society of Korea Conference
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• 2003.03a
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• pp.213-213
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• 2003

저온소성 가능하며 저 융점유리인 고 투과율의 Pb-free 조성으로서 PDP(Plasma Display panel)의 투명유전체에 응용하고자 P$_2$O$_{5}$-ZnO-RO 계인 인산염 유리의 열적, 광학적성질을 연구하였다. 이 삼원계인 인산염유리계를 PDP의 투명 유전체에 응용하기에는 열적특성에서 문제점이 제기되어, (30-50)P$_2$O$_{5}$ - (20-50)ZnO - (15-45) RO (mol%)계에 유리망목형성제인 A1$_2$O$_3$, SiO$_2$, B$_2$O$_3$등을 첨가하여 열적성질 및 소성후 투광성 등을 조사하였다. 열적특성은 DTA와 TGA를 이용하여 유리전이점(Tg) 및 선팽 창계수(CTE)와 연하점(Ts) 을 측정하였으며, 투광성은 500-58$0^{\circ}C$에서 1시간동안 소성하여 UV-visible spectrometer을 이용하였다 그 결과로, 380-46$0^{\circ}C$의 Tg와 8-$10^{-6}$K의 CTE 및 70-80%의 광투과율을 나타내었다. 이러한 결과는 P$_2$O$_{5}$-ZnO-RO계는 PDP의 투명유전체에 적용하기에는 상당히 높거나 낮은 Tg를 형성하였지만 유리형성제를 수 mol%을 첨가함으로써 적절한 Tg점과 높은 투과율을 얻을 수 있었다.수 있었다.

• Applied Biological Chemistry
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• v.37 no.2
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• pp.77-84
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• 1994

Sweetpotatoes were baked (BK), microwaved (MW), microwaved/baked (MWBK), and microwaved/hold/microwaved (MWHO). Sugars, Huntercolors, compression and shear forces, sensory scores, moisture content, starch, and alcohol insoluble solids (AIS) were determined for each treatment. The BK roots contained higher (p<0.05) amount of sugars and less (p<0.05) starch. The MW roots contained higher (p<0.05) amount of starch, AIS, and less (p<0.05) sugar. The BK product resulted in the least (p<0.05) compression and shear forces needed to break it. The MW product demanded the greatest (p<0.05) force. The MWHO showed very similar results to the BK. Sensory scores for the BK and the MWHO sweetpotatoes were very acceptable. In color scores, the MWHO products were very acceptable and similar to the BK in flavor.

• Korean Journal of Food Science and Technology
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• v.15 no.3
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• pp.215-219
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• 1983

Rheological properties of the dough made from milled wheat products of various particle size, i.e., wheat shorts, girls and flour, and their effect on the loaf-volume potential of whole wheat bread were investigated in this study. One Korean wheat variety 'Cho-Kwang' was tested for suitability in whole wheat bread. The percent ash and protein content of the milled wheat products were 2.3% and 13.7% respectively. Ranges of 7.3, 5.6 and 4.8 mixograph peak-height were observed in Fraction 1(wheat flours), Fraction 2 (wheat girts) and Fraction 3(wheat shorts), respectively. Dought stability of Fraction 1 did not decreased appreciably as compared to that of commercial first grade baker's flour. Bread-baking test employing a standard formula showed that the wheat grits (0.2-0.5 mm in diameter) appeared to be the limit beyond which a rapid decrease in loaf-volume potential was noted. Optimum loaf volume and crumb characteristics were obtained in 80% wheat grits/20% wheat flour blend.

• Communications of Mathematical Education
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• v.15
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• pp.293-298
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• 2003

0은 인류 문명의 발전에 가장 큰 영향을 미친 숫자이다. 그러나 0은 일반적인 숫자의 역할을 넘어 철학적인 의미를 가지고 있다. 이러한 철학적인 의미 때문에 그리스인들에게 알려져 있었지만 받아들여지지는 않았다. 수의 추상적 개념(抽象的槪念)은 구체적인 물체의 취급에서 얻어지는 것이다. 따라서 산술적인 진리인 2+1=3 과 같은 것은 구체적인 물체를 조작하는 경험에서 얻어질 수 있는 반면, 우리의 경험상 존재하지 않는 0(영)의 개념은 쉽게 발견될 수 있는 성질이 아니었던 것이다. 그러나 모든 수학적 발견 중에서 0 이란 숫자만큼 인간 지성의 일반적 진전에 공헌한 것은 없다고 해도 과언이 아니다. 초기에는 0이 산술 계산의 편리성으로 인하여 널리 보급되었으나, 그 의미를 깨닫고 난 후 미적분과 무한의 개념과도 동전의 양면과 같다는 사실을 알게 되었다. 본 논문은 수학뿐만 아니라 인류문명에 거대한 진보를 이루게 한 0의 역사를 살펴보고, 이것이 왜 인도에서 나타나게 되었는가를 살펴보았다.