• Journal of the Korea Concrete Institute
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• v.28 no.5
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• pp.593-600
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• 2016

The paper presented investigates the effects of kaolinite on strength properties of alkali-activated multi-component cement. The binders of this study was blended of ground granulated blast furnace slag (GGBFS), fly ash (FA), silica fume (SF) and kaolinite (KA). In this study, the specimens of combination of 20%~70% GGBFS, 10%~60% FA, 10% SF (constant ratio) and 10%~50% KA binder were used for strength properties tests. The water/binder ratio was 0.5. The binders (GGBFS + FA + SF + KA) was activated by sodium hydroxide (NaOH) and sodium silicate ($Na_2SiO_3$) was 10% by total binder weight (10% NaOH + 10% $Na_2SiO_3$). The research carried out is on the compressive strength, water absorption, ultrasonic pulse velocity (UPV) and X-ray diffraction (XRD). The compressive strength decreased as the contents of KA increase. One of the major reason for this is the low reactivity of KA compared with other raw materials used as precursors such as GGBFS or FA. The presence of remaining KA indicates that the initially used quantity has not fully reacted during hydration. Moreover, the results have indicated that increased of KA contents decreased UPV under all experimental conditions. The drying shrinkage and water absorption increased as the content of KA increase. Test result clearly showed that the strength development of multi-component blended cement were significantly dependent on the content of KA and GGBFS.

• Economic and Environmental Geology
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• v.37 no.2
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• pp.245-253
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• 2004

The 36km-long Daebo-Campo coast has a well-developed marine terraces divided to six steps by elevation of paleoshoreline : 0.5 m(T1), 10 m(T2), 30 m(T3), 40 m(T4), 60 m(T5) and 75 m(T6). The 2$^{nd}$ and 3$^{nd}$ platforms in Daebo to Guryongpo are wider and more distinctive than those of Guryongpo to Gampo. The 3$^{nd}$ terrace of 30 m high is subdivided to two flights as lower(T3b) and upper(T3a) by old sea cliff. Platform age is unclear because of coral fossil free. However, the terrace age could be determined with convergent OSL ages from beach sediments on 2$^{nd}$ step(T2). OSL ages of the terrace of 10 m high range in 60-70 ka. It reveals that the 2$^{nd}$ -step platform correlates to Oxygen Isotope Time scale, substage 5a(ca. 80 ka), and that uplift rate is ca. 0.19 m/ka for 2$^{nd}$ terrace at Daebo-Campo coast. If considering equivalent uplift rate for all terraces since the Late Pleistocene, the 3$^{rd}$ and 4$^{th}$ terraces would be 5e substage and 7 stage. The 30 m-high terrace provides a good indicator for uplift at Daebo-Gampo coast since 125,000 yrs(MIS 5e). It suggests that the local neotectonic deformation might cause an optional uplift rate of ca. 0.19 m/ka along the SE coast of Korea.

• Horticultural Science & Technology
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• v.29 no.5
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• pp.456-460
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• 2011

This study was carried out to compare the pattern of mutant variation and to evaluate the characteristics of mutants obtained by gamma irradiation in rose 'Kardinal'. Forty four rooted cuttings of 'Kardinal' were irradiated at 70 Gy gamma-ray dose from a $^{60}Co$ source to induce mutants in 2002. The irradiated plants were planted in field, and observed spotting of petal color mutants from 2002 to 2004. Four different kinds of mutant twigs with each different color flower were obtained from the irradiated 'Kardinal' with red petal. After being identified to be a stable mutant from 2004 to 2008, each mutant line propagated by cutting was hydroponic-cultured to evaluate the characteristics in the greenhouse from 2008 to 2009. Four mutant lines obtained from 'Kardinal' with red petal (Red group, 44A, 45B) include KA1 with light pink petal (Red group, 55B-55D), KA2 with pink petal (Red group, 63A-63B), KA3 with deep pink (Red purple, N57A-N57C), and KA4 with orange red (Red group, 43A-43B). Diameters of each flower in four mutant lines were different from 'Kardinal'. The line KA1 was 9.5 cm wide, and it showed the smallest diameter when compared to other mutants. While the line KA2 was the largest one with 12.5 cm 'Kardinal'. Petal number per flower was also variable among the mutants. The line KA2 had 39.8 petals being the largest number among the mutants, while the line KA1 was the lowest one compared to 35.5 petals of 'Kardinal'. Petal color was measured by using colorimeter. Brightness (L) measured at each petal of four mutants increased more than 'Kardinal'. CIE Lab values, a and b decreased more than 'Kardinal' at the petal color of three mutants except the line KA4. Characteristics of shoot, leaf, etc. from four mutants were also different from the ones of 'Kardinal'. The line KA1 was shortest in shoot, node and peduncle length, and lowest in prickle number. The reverse side of leaves was reddish green color in 'Kardinal' as well as the line KA4, but green color in the line KA1, KA2, and KA3.

• Korean Journal of Microbiology
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• v.29 no.4
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• pp.238-242
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• 1991

Extracellular laccase secreted from Pleurotus ostreatus was activated by $Cu^{2+}$ and $Cu^{+}$ . The enzyme was strongly inactivated by 8-hydroxyquinoline, potassium cyanide, sodium azide, sodium bisulfite and 2-mercaptoethanol. The two ionogenic groups, which have pKa values of 5.60-5.70 and 6.70-6.85 respectively, were found to relate with the active site of this enzyme. The oxidation reactions were brought about by initial single electron transfer process on the active site. The enzyme was found to be a metalloprotein which had about 3.9 cupric ions per molecule of protein as a prosthetic group. The enzyme showed a strong peak at 605 nm and a weak shoulder at 330 nm in UV-Visible absorption spectrum. Both signals disappeated upon treatment of the enzyme with 4 electron equivalent ascorbate. These results indicate that type I Cu peak and type III Cu shoulder are present in laccase.

• Journal of the Korean Chemical Society
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• v.23 no.4
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• pp.243-247
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• 1979

Kinetics of the reaction of phenethyltosylate with substituted pyridines at 50, 60 and 70$^{\circ}C$ in acetonitrile were investigated by an electric conductivity method. The effects of substituents on the reaction of phenethyltosylate with pyridines were discussed. The rates of reaction were increased with electron donating power of substituents of pyridines. The isokinetic relationship was shown $E_{\alpha}$ and ${\Delta}S^{\neq}$, it's temperature was 240$^{\circ}$K. Bronsted plots were excellent linear except for 4-amino pyridine given by the following equation, logk=O. 22pKa-3.71 (r=O. 986). According to a plot of log k against Hammett substituent constants, the Iinearity was good except for bamino pyridine too, log k= -1.330${\sigma}$+0.08 (r= -0.987). In both cases, deviation of 4-amino pyridine from linearity was considered to solvent effect, resonance effect and ${\sigma}$ value itself. From all the above results, this reaction was found typical $S_N2$ reaction which the rates of reaction was determined by C…N bond formation at transition state.

• Current Industrial and Technological Trends in Aerospace
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• v.5 no.1
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• pp.39-55
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• 2007

인류는 달을 보며 우주개발에 대한 꿈을 꾸어왔다. 60년대에서 70년대 중반까지 미 소간의 우주경쟁으로 달 탐사에 큰 예산을 들여 마침내 인류를 달에 착륙시켜 달 탐사를 실현할 수 있었다. 이젠 화성에 인류를 보내기 위한 전초기지를 달에 구축하려고 다시금 미국이 달 탐사를 가동시켰다. 이에 따라 세계 여러 나라가 달에 대해 다시 관심을 고조 시키고 있다. 그래서 이 논문에서는 90년대와 최근에 재 시작된 달 탐사위성의 개발동향을 조사하여 기술하였다. 대상 위성 프로젝트는 미국의 클레멘타인과 루나 프로스펙터, 유럽연합의 스마트-1호, 일본의 셀레네, 중국의 창어-1호, 인도의 찬드라얀-1호, 미국의 LRO 달 탐사 궤도선, 러시아의 루나-글로브 위성들의 주요특성과 탑재체, 지상국, 임무궤적 및 달 임무 궤도에 대해 개괄적으로 기술하였다. 기술 특징으로는 위성 제작기술 발전에 따라 경량화에 중점을 두어 위성을 소형화 하였으며, 통신방식에 있어서는 X 및 Ka대역을 사용하여 데이터 전송속도를 현저히 증가 시켰으며, 위성 및 지상의 안테나의 크기를 줄일 수 있었으며, 전기추력기를 사용하여 소형위성으로도 달 탐사를 실현시켰다. 그리고 다른 나라에서 개발되는 달 탐사위성의 개발 예산을 살펴보면 약 1억불 정도이면 소형 급의 위성을 개발하여 달 궤도에 진입시켜 달 과학탐사 임무를 수행할 수 있다고 할 수 있겠다. 따라서 우리나라도 지난 15년 이상 지구궤도 위성을 성공적으로 개발하며 구축한 기술을 바탕으로 달 탐사 위성의 개발에 대한 가능성을 가지고 있다고 본다. 이제 우리나라도 인류의 미래우주개발의 일익을 담당하고자 달 탐사위성 프로젝트를 준비해야한다

• Proceedings of the Korean Vacuum Society Conference
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• 2000.02a
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• pp.179-179
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• 2000

음극의 크기에 따라 발생된 전자빔 전류가 도파관 영역에서 공간 전하 한계 전류를 초과할 경우 형성되는 가상 음극 (Virtual Cathode)을 이용한 축 방향으로의 고출력 마이크로파 발생 및 진단에 관한 연구를 수행하였다. 먼저 실험에 앞서 전산모사를 통해 결과를 예측하고 실험을 통해 확인하는 순으로 하였다. 전산 모사는 2-1/2차원 Partical-In-Cell(PIC) 코드인 "MAGIC"을 사용하여 축 방향으로 진행하는 새로운 개념의 가상 음극발진기를 모사하고, 정확한 경과를 얻기 위해 강렬한 상대론적 전자빔 발생 장치인 "천둥"( 최대 전압 600kV, 최대 전류 70KA, 60ns)을 사용하여 전산 모사에 넣어줄 전류값을 얻었다. 음극의 반지름이 2.5cm 일 때 전파되는 최대 출력이 약 800MW인 마이크로파가 발생되었고, 이때 출력변환 효율이 약 30%임을 전산모사를 통하여 알 수 있었다. 또한 전파하는 전기장의 축방향 성분(Ez)의 반지름 방향에 대한 분포 특성을 통하여 주된 전파 모드가 TM01와 그 상위모드의 조합으로 이루어졌음을 알았고 이때 기대되는 동작 진동수는 5~7 GHz임을 전산 모사 결과로부터 알 수 있었다. 실험을 통해서도 음극의 크기가 2.5cm 때, 최대 출력이 약 520MW인 마이크로파를 발생하였고, 이 때 출력 변환 효율은 약 8%이고, 방전 사진을 통해서 주된 동작 모드가 TM01와 그 상위모드의 조합으로 이루어졌음을 알았고, 이때 주된 출력 진동수는 5~6 GHz임을 알 수 있었다.는 5~6 GHz임을 알 수 있었다.

• Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
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• 2008.11a
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• pp.20-21
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• 2008

Ferroelectric vinylidene fluoride-trifluoroethylene ($VF_2$-TrFE) copolymer films were directly deposited on degenerated Si ($n^+$, 0.002 $\Omega{\cdot}cm$) using by dip coating method. A 1 ~ 3 wt% diluted solution of purified vinylidene fluoride-trifluoroethylene ($VF_2$:TrFE=70:30) in a dimethylformamide (DMF) solvent were prepared and deposited on silicon wafers using dip coating method for 10 seconds. After Post-Annealing in a vacuum ambient at 100~200 $^{\circ}C$ for 60 min, upper aluminum electrodes were deposited by thermal evaporation through the shadow mask to complete the MFS structure. The ferroelectric $\beta$-phase peak of films, depending on the annealing temperature, started to show up around $125^{\circ}C$, and the intensity of the peak increased with increasing annealing temperature. Above $175^{\circ}C$, the peak started to decrease. The C-V characteristics were measured using a Precision LCR meter (HP 4284A) with frequency of 1MHz and a signal amplitude of 20 mV. The leakage-current versus electric-field characteristics was measured by mean of a pA meter/DC voltage source (HP 4140B).

• Archives of Plastic Surgery
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• v.47 no.1
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• pp.9-14
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• 2020

Background Eyelids vary in morphology and structure depending on age, sex, and race. Usually, one-dimensional measurements are used to evaluate blepharoplasty outcomes. However, in recent years, three- or four- directional enlargements of the eyelid have been used for blepharoplasty in Asian patients, and the outcomes of techniques such as lateral canthoplasty or canthotomy and medial epicanthoplasty with increased scleral area cannot be analyzed using marginal reflex distance 1 or the area of corneal exposure. Therefore, we describe the use of a measurement method based on the eyeball exposure area (EEA). Methods To obtain normal EEA values by age and sex, 320 individuals were recruited. The participants were divided into eight age groups (n=40 in each group: female subjects, n=20; male subjects, n=20): 10-19, 20-29, 30-39, 40-49, 50-59, 60-69, 70-79, and 80-89 years. The EEA value was obtained by dividing the exposed area by the total eyeball area. The normal EEA values and differences in EEA according to age and sex were calculated. Results The mean EEA values for male and female subjects were 66.86% ±9.20% and 71.48%±10.48%, respectively. In each age group, the EEA values of females were higher than those of males. EEA decreased significantly with age in both male and female subjects (P<0.05). Conclusions We determined normal EEA values according to age and sex. EEA can be used as an indicator of the outcome of blepharoplasty.

• Food Science and Preservation
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• v.16 no.6
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• pp.991-998
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• 2009

We used pears to manufacture wine, and analyzed changes in pH, acidity and ethanol and sugar content during fermentation. Pear wine with added ginger (to improve quality) did not differ from ginger-free wine in pH or acidity level. The ethanol content of pear wine was the highest (13.0%, v/v) inpear wine with 0.1% (w/v) added ginger compared to pear wine with no ginger, and sensory tests examining taste and color yielded the highest scores for pear wine with 0.2% (w/v) ginger. To assess storage stability, pear wine was treated for 30 minutes at $55^{\circ}C$, $60^{\circ}C$, $65^{\circ}C$, or $70^{\circ}C$. Unheated pear wine showed rapid changes in pH and acidity level after 30 days of storage, whereas pear wine treated for 30 minutes at $60^{\circ}C$ did not show such changes. Total organic acid levels in pear wine increased by 0.71% and 0.89% (v/v), respectively. The free sugar level in pear wine decreased from 12.05% to 3.13% (w/v). Turning to phenolic compounds, caffeic acid, catechin, and epicatechin contents in pears were 1.64, 1.40, and 0.23 mg/100mL, respectively, with diverse compositions. Caffeic acid levels in pear wine decreased sharply to 0.12 mg/100 mL upon fermentation, whereas free catechin inpear wine increased to 1.16 mg/100 mL compared with 0.28 mg/100 mL in pears. Free arbutin increased from 8.34 mg/100 mL in pears to 10.39 mg/100 mL in pear wine. The free amino acid content of pear wine was 118.5 g/100 mL, but the levels of serine, alanine, glutamic acid, and aspartic acid decreased sharply upon fermentation, with corresponding increases in tyrosine, GABA, lysine, and arginine.