• Proceedings of the Korean Society of Developmental Biology Conference
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• 2003.10a
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• pp.132-132
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• 2003

멸종위험성이 높은 재래돼지를 유전자원으로서 안전하게 보존하고 유전적 다양성을 유지하기 위해 체내수정란의 동결보존 방법을 수행하였다. 재래돼지의 과배란유기는 altrenogest를 1일 20mg씩 18일 경구투여하고 PMSG 500~l,000IU 근육주사후 80시간에 hCG 500~750IU를 근육주사하였다. 발정이 관찰된 개체는 발정개시후 12시간과 24시간에 자연교배 또는 액상정액을 이용하여 2회씩 수정시켰다. 최종 수정후 5일째에 외과적으로 개복수술하여 FBS가 5% 첨가된 D-PBS 관류액으로 자궁으로부터 수정란을 회수하여 상실기, 배반포기, 확장배반포기의 수정란으로 구분하였다. 회수된 수정란은 FBS가 20% 첨가된 D-PBS의 0.4, 0.8, 1.4M glycerol 항동해제에 각 단계별로 10분씩 평형시킨후 수정란동결기(CL863, Australia)를 이용하여 18$^{\circ}C$부터 -7$^{\circ}C$까지 2$^{\circ}C$/min의 냉각속도와 -7$^{\circ}C$부터 -35$^{\circ}C$까지 0.5$^{\circ}C$/min의 동결속도(실험1), 1$^{\circ}C$/min의 냉각속도와 0.3$^{\circ}C$/min의 동결속도(실험 2)로 동결시켰다. 또한 FBS가 20% 첨가된 D-PBS의 ethylene glyco1(EG) 1.8M의 항동제에 15분간 평형시킨후 실험 1과 동일한 방법으로 동결시켰다(실험 3). 동결수정란의 융해는 37$^{\circ}C$의 항온수조에서 30초간 실시하였다. 항동해제로 glycerol을 이용한 수정란은 융해후 3가지 농도로 0.3M sucrose, 0.8M glycerol, 0.4M glycerol을 첨가한 D-PBS에 각각 10분씩 단계적으로 정치시킨 다음, 10% FBS 첨가 mNCSU-23으로 3회 세척했다. 항동해제로 EG를 이용한 수정란은 융해후 즉시 D-PBS에 각각 10분간 정치시킨 다음, 10% FBS 첨가 mNCSU-23으로 3회 세척했다. 항동해제가 제거된 수정란은 FBS가 10% 첨가된 mNCSU-23 배양액에서 39$^{\circ}C$, 5% $CO_2$ 배양기에 48시간 배양하면서 생존여부를 판단하였다. 실험 2에서 확장배반포배 수정란이 25.3%의 생존율을 나타내었으며, 실험 1과 실험 3에서는 수정란의 형태와 관계없이 생존성을 확인할 수 없었다. 이상의 결과로 보아 glycerol 완만동결에서는 확장배반포기 수정란 이상이 보존가능한 것으로 추정되나 더 추가적인 연구가 요구된다.

• Proceedings of the Korean Information Science Society Conference
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• 2006.06c
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• pp.274-276
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• 2006

e-seal은 RFID(Radio Frequency IDentification) 기술을 사용하여 원격에서 자동으로 봉인상태를 확인할 수 있는 컨테이너 봉인 장치를 말한다. RFID의 특징상 반도체 칩에 기록된 정보를 제 삼자가 쉽게 판독 및 변조할 수 있다는 취약점으로 인하여 활성화되지 못하고 있는 실정이다. ISO에서는 RFID의 취약점을 보안하기 위한 표준작업(ISO 18185)을 진행 중이다. 이 중, ISO 18185-4는 e-seal에 저장되는 자료나 리더와의 RF통신에서 데이터 보호를 위한 표준이다. 이와 관련된 연구로는 인증 프로토콜과 ISO 18185-4를 위한 보고서로 제출된 보안 프로토콜이 있다. 제안된 e-seal 보안 프로토콜을 적용하기 위해서는 e-seal과 리더 간의 데이터를 암/복호화할 키가 필요하지만, 키 서버를 통해 전달받은 마스터 키를 데이터 암/복호화 키로 바로 사용하는 것은 보안 상의 문제점을 야기할 수 있기 때문에 PRF(Pseudo Random Function)을 이용하여 마스터 키로부터 MTK(Mutual Transient Key)를 유도하고, MTK를 암/복호화 키로 사용해야 한다. 기존의 PRF는 일방향 해시 함수(MD5, SHA 등)를 기반으로 하는 HMAC[2. 3]을 일반적으로 사용하였다. 그러나 일방향 해시 함수는 e-seal과 같은 제한된 자원을 갖는 환경에 적합하지 않다. 따라서, 본 논문에서는 e-seal 보안 프로토콜을 위한 효율적인 PRF을 제안한다. 기존의 일방향 해시 함수 기반이 아닌 블록 암호화 알고리즘을 기반으로 하는 MAC을 이용하여 PRF을 보다 효율적으로 구현하였고, 블록 암호화 알고리즘은 AES를 선택 합성체 $GF((2^4)^2)$을 통해 하드웨어 모듈을 최적화 하였다. AES를 기반으로 하는 MAC은 HMAC에 비해 면적 및 처리율에서 뛰어난 결과를 보여주었다.<0.01).이상의 연구 결과, cook-chill생산 시 녹차 추출물의 첨가가 미생물적 품질유지에 효과가 있다고 사료되는 바 본 연구결과를 기초로 급식소에서 음식 생산 시 녹차 추출물 및 천연 항균성 물질 첨가에 따른 미생물적 품질 및 관능적 품질검사를 통한 레시피 개발에 관한 지속적인 연구가 수행되어야 하겠다.다.다리다보니 점심시간을 활용할 수 없게 되는 문제점에 대한 재검토가 필요하다. 따라서 차후 학교급식의 안전성 확보를 위한 급식환경 개선의 일환으로 식당공간 확보 시 신속한 시간 내에 급식이 가능하도록 넓은 공간과 쾌적한 환경의 식당 조성에 대해 관심을 기울여야 할 것으로 사료된다. 이상 여부를 반영하는 임상증상의 빈도가 높은 청소년기 남녀 중학생의 경우 아침과 저녁의 결식빈도 및 외식과 간식의 빈도가 높았고, 아침식사의 질과 체형만족도가 낮은 것으로 나타나 청소년의 건강과 식습관 및 체형만족도가 상호 관련성이 높은 것으로 나타났다. 따라서 본 연구 결과는 성장기 청소년의 건강 유지를 위하여 바람직한 식습관의 중요성을 재인식할 수 있었으며, 올바른 식습관 확립을 위한 영양교육의 중요성이 재확인되었다.경제적일 것으로 판단된다.er 90 % of good relative dynamic modulus of elasticity due to fineness of formation caused by the increase of the unit powder content and the improvement of flowability, without regard to the replacement of crushed stone fines. Therefore, it can be said that the usage of crushed stone fines can control the strength of super flowing concrete by replacement and re

• Applied Biological Chemistry
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• v.6
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• pp.33-36
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• 1965

1. The extraction of securine, an alkaloid, from Securinega suffruticosa Rehder growing in Korea was investigated. 2. The distribution of the source plant in Korea is considered to be most intense among the Fareast countries. 3. The extracted material was identified to be genuine securinine viewing from melting point and microscopic observation. 4. The yield of the substance in this study was 0.075% in average. The less amount of recovery may be due to the collection of the plant in October instead of that in the prime season. 5. There should be more efficient way in the separation of resinous impurities from the crude product. Application of Chromatographic technique and selection of more efficient solvent will be investigated hereafter.

• Journal of Nuclear Fuel Cycle and Waste Technology(JNFCWT)
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• v.16 no.4
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• pp.479-490
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• 2018

The granite melting concept, which was suggested by Gibb's group for the closing of a deep borehole, was experimentally checked for KURT granite. The granite melting experiments were performed in two pressure conditions of atmospheric melting with certain inorganic additives and high pressure melting formed by water vaporization. The results of atmospheric tests showed that KURT granite started to melt at a lower temperature of $1,000^{\circ}C$ with NaOH addition and that needle shaped crystals were formed around partially melted crystals. In high pressure tests, vapor pressure was increased by adding water with maximum pressure of about 400 bars. KURT granite was partially melted at $1,000^{\circ}C$ when vapor pressure was low. However, it was not melted at vapor pressures higher than 200 bars. Therefore, it was determined that high pressure with a small amount of water vapor more effectively decreased the melting point of granite. Meanwhile, high temperature and high pressure vapor caused severe corrosion of the reactor wall.

• The Korean Journal of Mycology
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• v.27 no.1 s.88
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• pp.10-14
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• 1999

A single phase composter was constructed by modifying the conventional mixer of sawdust for the cultivation of oyster mushroom Pleurotus ostreatus. The machine was designed on the basis of 3-phase-1 system which was controlled in prewetting, pasteurization and fermentation processes. In composting 200 kg of straw and cotton waste in the machine, it took 20 minutes in prewetting step and also to hours at $65^{\circ}C$ in pasteurization process. Postfermentation by aerothermophiles was completed by treating the compost at $45^{\circ}C-50^{\circ}C$ for 48 hours which was shorten 24 hours from the conventional method. In the postfermentation at high temperature, forced aeration and/or vigorous mixing process(es) played a great role in the improvement of spawn quality. The growth of mycelium of oyster mushroom was excellent in the culture combinated with 3 parts of surface inoculation and 7 parts of mechanical mixing.

• Korean Chemical Engineering Research
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• v.56 no.4
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• pp.585-591
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• 2018

Characteristics of nano-structured $SiO_2:Zn$ hollow powders prepared in the micro drop fluidized reactor process were investigated with respect to bandgap energy and surface activity. The $SiO_2:Zn$ hollow powders were successfully prepared continuously in the one step process with reasonable production efficiency, with varying the amount of THAM (tris(hydroxymethyl)-aminomethane) additive and concentration of $Zn^{2+}$ ions. The doping of $Zn^{2+}$ ions into $SiO_2$ lattice led to the reduction of bandgap energy by forming the acceptor level of $Zn^{2+}$ below the conduction band of $Si^{4+}$ ions. The hollow shape also contributed to reduce the bandgap energy of $SiO_2:Zn$ powders. The doping of $Zn^{2+}$ ions into $SiO_2$ hollow powders could enhance the surface activity by forming SiO-H stretching and oxygen vacancies at the surface of $SiO_2:Zn$ powders.

• Analytical Science and Technology
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• v.18 no.1
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• pp.27-34
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• 2005

$Li_2B_4O_7$ and $Na_2B_4O_7$ were synthesized with boron isotopic standard material for the measurement of boron isotopes of positive ions (PTIMS) such as $Li_2BO_2{^+}$ (mass 56, 57) and $Na_2BO_2{^+}$ (mass 88, 89) instead of boron mass 10 and 11. The negative ions (NTIMS) such as $^{10}BO_2{^-}$ and $^{11}BO_2{^-}$(mass 42와 43) were also measured with the same boron isotopic standard material. The precision and accuracy were compared between each method, and prescan of isobaric effect was studied. Good result was obtained from NTIMS method which provided the stable and enough peak intensities with good precision and accuracy. The measurement of boron isotopes were performed in ground water sample with about 8 ng-B ($5{\mu}L$ sample solution) obtained from IAEA for international inter-comparison analysis. The standard deviation was found to be 0.03%. Boron content of this ground water was measured using the NTIMS-IDMS. The result was $1.65{\pm}0.003ug-B/mL$ which was better precision compared to the ICP-AES result.

• The Korean Journal of Pesticide Science
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• v.20 no.3
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• pp.264-270
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• 2016

This study was conducted to compare of the pesticide residue amounts in fruit trees applied by different sprayers and spray volumes. Apple tree was used as a sample tree, and speed sprayer, power sprayer and knapsack motorized sprayer were tested. For similar sprayer and spray volume, the concentration of fluquinconazole and flusilazole in apple leaves were obtained respectively, for speed sprayer 8.33 and 2.15 mg/kg, for power sprayer 4.56 and 1.10 mg/kg, and for knapsack 4.55 and 1.12 mg/kg. The results showed that the treatment using speed sprayer had highest efficiency. The pesticide residues in apple leaves sprayed by 3 different spray volumes (560, 336 and 230 L/10a) using speed sprayer were 10.76 mg/kg, 8.32 mg/kg, 6.04 mg/kg on fluqinconazle and 3.04 mg/kg, 2.14 mg/kg and 1.47 mg/kg on flusilazole, respectively, indicating that the higher the volume, the higher the residues. The results from this study can be used as scientific basis for evaluating the field trial data for pesticide registration and the spray volume setting for fruit trees in Korea.

• Applied Chemistry for Engineering
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• v.8 no.4
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• pp.575-581
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• 1997

UDs were synthesized from two different polyols(PTMG, PBEAG), ionic chain extender(DMPA), EDA with $H_{12}-MDI$. PU/PMMA hybrids were prepared with free radical polymerization of MMA monomer in MMA-swelled PUD. PUD particle size and film properties were investigated ionic content and polyol type. Mechanical and thermal properties of PU/PMMA hybrid film were studied in terms of PU's ionic content and the venation of PU/PMMA compositions. As DMPA content increased from 2wt% to 10wt% in PUD, particle size of PUD decreased. PUD's particle size with ester type polyol was found to be smaller then ether type polyol used. Phase separation between hard segment(HS) and soft segment(SS) with ionic contents in PU was shown by the thermal, mechanical property measurement. Although the composition of MMA was changed from 0 to 40 wt% in PU/PMMA hybrid, the particle size of the hybrid did not increase. Using the ester type polyol, tensile strength of hybrid was found to increase by 2wt% - 6wt% DPMA content, but as higher content the strength of hybrid decreased. Moreover with the ether type polyol, tensile strength of hybrid was observed to increase by 2wt% - 4wt% DMPA content, while decreasing at higher content. PU and PMMA polymer molecule being mixed in molecular level was confirmed from the pattern of $T_g$ in DSC thermogram.

• Applied Chemistry for Engineering
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• v.29 no.2
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• pp.215-224
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• 2018

Influences of the magnetic field on 5, 10 and 15 wt% (1.5, 3 and 4.5 M) HCl solution behaviour, which has widespread applications in petroleum well acidizing, were investigated in various conditions. Differences in the pH of magnetized hydrochloric acid compared to that of normal hydrochloric acid were measured. Taguchi design of experimental (DoE) method were used to model effects of the magnetic field intensity, concentration, velocity and temperature of acid in addition to the elapsed time. The experimental results showed that the magnetic field decreases [$H^+$] concentration of hydrochloric acid up to 42% after magnetization. Increasing the magnetic field intensity (with 28% contribution), concentration (with 42% contribution), and velocity of acid increases the effect of magnetic treatment. The results also demonstrated that the acid magnetization was-not influenced by the fluid velocity and heating. It was also displayed that the acid preserves its magnetic memory during time. The optimum combination of factors with respect to the highest change of [$H^+$] concentration was obtained as an acid concentration of 10% and an applied magnetic field of 4,300 Gauss. Due to the reduction of HCl reaction rate under the magnetization process, it can be proposed that the magnetized HCl is a cost effective and reliable alternative retarder in the matrix acidizing of hydrocarbon (crude oil and natural gas) wells.