• Journal of the Korean Chemical Society
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• v.42 no.1
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• pp.69-77
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• 1998

(3S,4S)-1-(t-Butoxycarbonylmethyl)-3-[(S)-1-(t-butyldimethylsilyloxy)ethyl]-4-(2-diazo-2-ethoxycarbonyl-1-oxoethyl)-2-azetidinone (14) was prepared from 4-styryl-2-azetidinone 7b via a sequence of reactions involving N-alkylation with bromoacetate, ozonolysis, oxidation, condensation with magnesium ethyl malonate, and diazo transfer reaction. (3S,4S)-3-[(S)-1-(t-Butyldimethylsilyloxy)ethyl]-4-(3-diazo-3-ethoxycarbonyl1-hydroxypropyl)-2-azetidinone (21) was also prepared from 4-formyl-2-azetidinone 5b via a sequence of reactions involving Wittig reaction, 1,3-dipolar cycloaddition with ethoxycarbonylformonitrile oxide, catalytic hydrogenation, and diazotization. However, the final cyclization of 14 or 21 to 1-hydroxycarbapenem or 1-hydroxycarbapenam by treating with $Rh_2(OAc)_4$ was unsuccessful.

• Bulletin of the Korean Chemical Society
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• v.27 no.10
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• pp.1708-1711
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• 2006

• Proceedings of the Optical Society of Korea Conference
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• 1991.06a
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• pp.98-101
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• 1991

The As2S3 thin film has a characteristics of optical modulation in both amplitude and phase. Since the As2S3 thin film can be used as a real-time reconfigurable optical filter, the fSDF filter can be optically fabricated on it. According to the modulation characteristics of the As2S3, the optimal fSDF filter recorded on this thin plate has the form of continuous amplitude and binary phase. Computer simulation and optical experiments on the optical pattern classification show that the As2S3 is suitable for the optical fSDF filter.

• Journal of the Korean Statistical Society
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• v.24 no.2
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• pp.507-518
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• 1995

The ordinary least squares based estiamte $S^2$ of the disturbance variance is considered in the linear regression model when the disturbances follow the first-order moving-average process. It is shown that $S^2$ is weakly consistent estimate for the disturbance varaince without any restriction on the regressor matrix X. Also, simple exact bounds on the relative bias of $S^2$ are given in finite sample sizes.

• Bulletin of the Korean Chemical Society
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• v.30 no.12
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• pp.3069-3072
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• 2009

• Elastomers and Composites
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• v.50 no.2
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• pp.87-91
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• 2015

Cure characteristics of non-oil-extended solution SBR (S-SBR_NO) and oil-extended solution SBR (S-SBR_ EO) compounds reinforced with silica/carbon black were investigated. Minimum and maximum torques of S-SBR_ EO compounds were much smaller than those of S-SBR_NO ones. Delta torques of S-SBR_NO compounds were greater than those of S-SBR_EO ones, and that of S-SBR_NO compound increased with increase in the 1,2-unit content. Optimum cure time ($t_{90}$) of S-SBR compound decreased with increase in the 1,4-unit content, whereas it increased with increase in the 1,2-unit content. Cure rate index of S-SBR compound increased with increase in the 1,4-unit content, whereas it decreased with increase in the 1,2-unit content. Comparing cure characteristics of S-SBR_NO and S-SBR_EO compounds with the same 1,2-unit content, $t_{90}$s of S-SBR_EO compounds were longer than those of S-SBR_NO ones and cure rate indices of S-SBR_EO compounds were smaller than those of S-SBR_NO ones.

• The Transactions of the Korean Institute of Electrical Engineers
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• v.41 no.5
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• pp.502-507
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• 1992

To improve temperature stability, 0.05Pb(SnS11/2TSbS11/2T)OS13T-0.35PbTiOS13T-0.60PbZrOS13T+0.4[wt%]MnO S12T piezoelectic ceramics were manufactured with the addition of CrS12TOS13T by Hot Press method. And the SAW delay line was fabricated and effects of CrS12TOS13T to the propagation characteristics of SAW was investigated, and the SAW filter was fabricated on C4 specimen added by 0.2[wt%] CrS12TOS13T whose propagation characteriatics of surface acoustic wave were the bast and its frequency characteristics was investigated. Electromechancal coupling factor(kS1sTS02T) was 3.11[%] and its temperature coefficient of the center frequency(CS1foT)was -21.27[ppm/$^{\circ}C$] in C4. The 31[MHz]]SAW IF filter of C4 scarcely had diffraction phenomena and therefore it was proper.

• 한국신재생에너지학회:학술대회논문집
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• 2009.06a
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• pp.871-872
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• 2009

본 연구에서는 석탄가스에 함유된 $H_2O/H_2S$ 농도변화에 따른 세가지 종류의 아연계 탈황제의 반응성능을 회분식 유동층반응기에서 분석하였다. 가스화에서 생성되는 가스의 조성은 모사가스를 이용하여 입구의 $H_2O$와 $H_2S$ 농도를 변화시켜 실험을 수행하였다. $H_2O$의 농도는 5%부터 30%까지 $H_2S$의 농도는 0.5%에서 2%로 변화시켜 탈황성능을 분석하였다. 실험 결과 $H_2O$의 농도가 증가할수록 탈황성능이 감소하였다. 입구의 $H_2S$ 농도가 증가할수록 탈황반응기 후단의 $H_2S$ 농도 역시 증가하였으나, 탈황성능은 최저 99.5%로 건식탈황제를 이용하여 99% 이상의 $H_2S$ 제거 성능을 보이는 것을 확인하였다.

• Proceedings of the Korean Society of Broadcast Engineers Conference
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• 2004.11a
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• pp.185-191
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• 2004

이 연구는 DVB-S2 BC(Backward Compatibility) 모드에서 대역폭 효율을 개선하기 위한 새로운 계층적 변조방식을 제안하였다. DVB-S2 표준은 기존 DVB-S 방송 서비스와의 역호환성을 위하여 비대칭 8-PSK를 사용하며, 이 방식은 DVB-S의 경우보다는 대역폭 효율이 개선되나 DVB-S2 NBC(Non Backward Compatibility) 모드보다는 개선도가 미약하다 이러한 문제점을 해결하기 위하여 DVB-S2 NBC에서 사용하는 16APSK 변조방식을 DVB-S2 BC 모드에서 사용할 수 있도록 변형하였으며, 변형된 16-APSK 방식에 대한 수신 성능을 통계적 방법을 통하여 분석하였다.

• Journal of Bio-Environment Control
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• v.31 no.3
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• pp.230-236
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• 2022

This study was carried out to produce two-flowered seedlings, harvest them early in a greenhouse, and extend the harvest period. This study was carried out to effectively produce the second truss blooming seedlings to harvest tomatoes early and extend the harvest period. For production of the second truss blooming seedlings (one stem), the nutrient solution EC was supplied at 1.5, 2.0, 2.5 dS·m^-1, and dynamic management (3.0 → 3.5 → 4.5 dS·m^-1). The seedling period was 60 days, which was 20-40 days longer than conventional seedlings, and 10 days longer than the first truss blooming seedlings (cube seedlings). The plant height was 78 and 77 cm in EC 2.5 dS·m^-1 and dynamic management respectively, which was shorter than EC 1.5 dS·m^-1 with 88 cm. As for the EC in the cube before formulation, dynamic management had the highest EC 5.5 dS·m^-1, and the cube supplied with EC 1.5 dS·m^-1 had the lowest. The production yield by treatment did not a difference among in the second truss blooming seedlings, but the first truss blooming seedlings showed lower productivity than second truss blooming seedlings. The second truss blooming seedling were harvested 35 days after planting on June 4, the first harvest date, and the first truss blooming were harvested in 42 days on June 11th. There was no difference in plant height and root growth due to bending at frequency planting. In the study on the production of the second truss blooming seedlings (two stem), the nutrient solution EC was supplied under 2.0, 2.5, 3.0 dS·m^-1, and dynamic management (3.0 → 3.5 → 4.5 dS·m^-1). The seedling period was 90 days, which was 40-50 days longer than conventional seedlings and 10 days longer than the first truss blooming seedlings (cube seedlings). Plant height was 80 and 81 cm in EC 2.0 dS·m^-1 and 2.5 dS·m^-1 respectively, but was the shortest at 73 cm in dynamic management. EC in the medium increased as the seeding period increased in all treatments. The dynamic management was the highest with EC 5.1 dS·m^-1. There was no difference in yield among EC treatments in the second truss blooming seedlings, which had a longer seeding period of about 10 days, produced 15% more than the first truss blooming seedlings. In order to shorten the plant height of the second truss blooming seedlings, it is judged that the most efficient method is increasing the concentration of nutrient solution.