• 한국구조물진단유지관리공학회 논문집
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• 제21권5호
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• pp.12-20
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• 2017

본 연구는 규산나트륨($Na_2SiO_3$)으로 활성화된 고유동 대량치환슬래그 시멘트의 기초특성에 관한 연구이다. 고로슬래그 미분말(GGBFS)은 보통포틀랜드 시멘트(OPC)의 40%에서 80%까지 질량치환하고 칼슘설포알루미네이트(CSA)는 2.5%와 5.0% 치환하였다. 규산나트륨($Na_2SiO_3$)은 전체 결합재(OPC+GGBFS+CSA) 질량의 2%와 4% 추가하였다. 모든 배합의 물-결합재 비(w/b)는 0.35이다. 본 연구에서는 미니슬럼프, V-funnel, 응결시간, 압축강도와 건조수축을 측정하였다. 실험결과 유동화제 양, V-funnel, 응결시간과 건조수축은 CSA와 $Na_2SiO_3$가 증가함에 따라 감소하였다. 그러나 압축강도는 CSA와 $Na_2SiO_3$가 증가함에 따라 증가하였다. 이러한 원인 중 하나는 CSA와 $Na_2SiO_3$가 GGBFS의 활성화를 촉진하였기 때문이다. 최고의 성능을 나타낸 배합은 CSA 5.0% + $Na_2SiO_3$ 4%를 혼합한 시험체이다.

• 농약과학회지
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• 제19권4호
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• pp.345-353
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• 2015

본 연구는 GC/NPD와 GC/MS를 이용하여 농산물 시료에 적용 가능한 MBI propionamide계 살균제 fenoxanil의 잔류 분석법을 확립하였다. 고추, 배추, 사과, 현미 및 콩을 대표 농산물로 설정하여 fenoxanil 단성분의 정량 및 확인 시험법을 개발하였다. 각각 농산물에 대한 추출은 acetone을 이용하였으며, 분배과정은 n-hexane/dichloromethane (80/20, v/v), 정제는 florisil 흡착제를 활용한 정제법을 적용하였다. 정량분석은 DB-5 capillary column을 GC/NPD에 장착하여 수행하였고, 각 농산물에 대한 정량한계는 0.04 mg/kg으로 설정 가능하였다. 회수율은 82.2-109.1%로 조사되었으며 농산물 시료의 종류 및 처리수준에 관계없이 7.2% 미만의 변동계수를 나타냈다. 정성적 확인을 위해 GC/MS를 이용, m/z 125.0, 188.9 및 293.0을 fenoxanil의 정성확인을 위한 선택적 이온으로 설정하였다.

• 대한전자공학회논문지TC
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• 제42권7호
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• pp.71-78
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• 2005

K-Best 알고리듬은 일정한 최대 복잡도를 가지기 때문에 ML (Maximum Likelihood) 수신기나 sphere decoding 수신기에 비해 실시간 구현에 적합한 알고리듬으로 알려져 있다. 그러나 ML 수신기에 가까운 성능을 내기 위해 충분히 큰 K값을 적용할 경우 여전히 높은 복잡도를 가지게 되며, 구현에 좀 더 적합하도록 작은 K값을 적용할 경우, 최대 복잡도는 낮아지는 반면오차 전달(error propagation)에 의해 높은 SNR 영역에서 에러 플로링(error flooring)이 발생하는 문제점이 있다. 본 논문에서는 이러한 오차 전달 문제를 해결하기 위해 각 레벨 별로 K값을 감소시키는 K-reduction 기법을 제안하였으며, 모의 실험을 통해 연산량 및 비트 오차 확률 측면에서 이득이 있음을 확인하였다.

• Advances in concrete construction
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• 제6권4호
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• pp.323-344
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• 2018

The study herein reports the impact of Steel Fiber (SF) and Ground Granulated Blast Furnaces slag (GGBFS) content on the fresh and hardened properties of fly ash (FA) based Self-Compacting Geopolymer Concrete (SCGC). Two series of self-compacting geopolymer concrete (SCGC) were formulated with a constant binder content of $450kg/m^3$ and at an alkaline-to-binder (a/b) ratio of 0.50. Fly ash (FA) was substituted with GGBFS with the replacement levels being 0%, 25%, 50%, 75%, and 100% by weight in each SCGC series. Steel fiber (SF) wasn't employed in the assembly of the initial concrete series whereas, within the second concrete series, an SF combination was achieved by a constant additional level of 1% by volume. Fresh properties of mixtures were through an experiment investigated in terms of slump flow diameter, T50 slump flow time, V-funnel flow time, and L-box height ratio. Moreover, the mechanical performance of the SCGCs was evaluated in terms of compressive strength, splitting tensile strength, and fracture toughness. Furthermore, a statistical analysis was applied in order to judge the importance of the experimental parameters, like GGBFS and SF contents. The experimental results indicated that the incorporation of SF had no vital impact on the fresh characteristics of the SCGC mixtures whereas GGBFS aggravated them. However, the incorporation of GGBFS was considerably improved the mechanical properties of SCGCs. Moreover, the incorporation of SF with the total different quantity of GGBFS replacement has considerably increased the mechanical properties of SCGCs, by close to (65%) for the splitting strength and (200%) for compressive strength.

• Journal of Microbiology and Biotechnology
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• 제30권3호
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• pp.391-397
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• 2020

In this study, we used a novel α-L-arabinopyranosidase (AbpBs) obtained from ginsenoside-converting Blastococcus saxobsidens that was cloned and expressed in Escherichia coli BL21 (DE3), and then applied it in the biotransformation of ginsenoside Rb₂ into Rd. The gene, termed AbpBs, consisting of 2,406 nucleotides (801 amino acid residues), and with a predicted translated protein molecular mass of 86.4 kDa, was cloned into a pGEX4T-1 vector. A BLAST search using the AbpBs amino acid sequence revealed significant homology with a family 2 glycoside hydrolase (GH2). The over-expressed recombinant AbpBs in Escherichia coli BL21 (DE3) catalyzed the hydrolysis of the arabinopyranose moiety attached to the C-20 position of ginsenoside Rb₂ under optimal conditions (pH 7.0 and 40℃). Kinetic parameters for α-L-arabinopyranosidase showed apparent K_m and V_max values of 0.078 ± 0.0002 μM and 1.4 ± 0.1 μmol/min/mg of protein against p-nitrophenyl-α-L-arabinopyranoside. Using a purified AbpBs (1 ㎍/ml), 0.1% of ginsenoside Rb₂ was completely converted to ginsenoside Rd within 1 h. The recombinant AbpBs could be useful for high-yield, rapid, and low-cost preparation of ginsenoside Rd from Rb₂.

• Journal of Microbiology and Biotechnology
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• 제27권1호
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• pp.9-18
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• 2017

Nine bacilli with fibrinolytic activities were isolated from doenjang, a traditional Korean fermented soy food. Among them, RSB34 showed the strongest activity and was identified as Bacillus amyloliquefaciens by 16S rRNA and recA gene sequencing. During growth on LB up to 96 h, RSB34 showed the highest fibrinolytic activity ($83.23mU/{\mu}l$) at 48 h. Three bands of 23, 27, and 42 kDa in size were observed when the culture supernatant was analyzed by SDS-PAGE and 27 and 42 kDa bands by fibrin zymography. The gene encoding the 27 kDa fibrinolytic enzyme AprE34 was cloned by PCR. BLAST analyses confirmed that the gene was a homolog to genes encoding AprE-type proteases. aprE34 was overexpressed in Escherichia coli BL21(DE3) using pET26b(+). Recombinant AprE34 was purified and examined for its properties. The $K_m$ and $V_{max}$ values of recombinant AprE34 were $0.131{\pm}0.026mM$ and $16.551{\pm}0.316{\mu}M/l/min$, respectively, when measured using an artificial substrate, N-succinyl-ala-ala-pro-phe-p-nitroanilide. aprE34 was overexpressed in B. subtilis WB600 using pHY300PLK. B. subtilis transformants harboring pHYRSB34 (pHY300PLK with aprE34) showed higher fibrinolytic activity than B. amyloliquefaciens RSB34.

• Asian-Australasian Journal of Animal Sciences
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• 제21권12호
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• pp.1703-1709
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• 2008

As genetic markers, single nucleotide polymorphisms (SNP) are very appropriate for the development of genetic tests for economic traits in livestock. Several microsatellite markers have been identified as useful markers for the genetic improvement of Hanwoo. Among those markers, ILSTS035 was recently mapped at a similar position with four SNPs (AH1_11, AH1_9, 31465_446, and 12273_165) in a linkage map of EST-based SNP in BAT6. Among the four SNPs, two SNPs (31465_446 and 12273_165) were analyzed using BLAST at the NCBI web site. The sequences including the 12273_165 SNP were identified at the intron region within the LOC534614 gene on the gene sequence map (Bos taurus NCBI Map view, build 3.1). The LOC534614 gene represents a protein similar to myosin heavy chain, fat skeletal muscle, embryonic isoform 1 in the dog, and myosin_1 (Myosin heavy chain D) in Macaca mulatta. In cattle, the myosin heavy chain was associated with muscle development. The phenotypic data for growth and carcass traits in the 415 animals were analyzed by the mixed ANCOVA (analysis of covariance) linear model using PROC GLM module in SAS v9.1. By the genotyping of Hanwoo individuals (n = 415) to evaluate the association of SNP with growth and carcass traits, it was shown that the 12273_165 SNP region within LOC534614 may be a candidate marker for growth. The results of the statistical analyses suggested that the genotype of the 12273_165 SNP significantly affected birth weight, weight of the cattle at 24 months of age, average daily gain and carcass cold weight (p<0.05). Consequently, the 12273_165 SNP polymorphisms at the LOC534614 gene may be associated with growth in Hanwoo, and functional validation of polymorphisms in LOC534614 should be performed in the future.

• 대한전자공학회논문지TC
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• 제42권9호
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• pp.41-48
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• 2005

본 논문에서 장시간 귀환 기법과 단시간 귀환 기법을 결합하는 MIMO 다중 사용자 시스템을 제안하고 성능을 분석하였다 통화 초기에 목표 심볼 오류와 목표 전송를을 고려하여 활성 안테나 수, 성상도, 전송 전력과 같은 장시간 귀환 기법을 수신단에서 전송단에 귀환한다. 이 후에 수신단에서 단시간귀환기법으로서 활성안테나 인덱스를 주기적으로 전송단에 알려준다. 모의실험을 통해 장시간 귀환 기법 또는 단시간 귀환 기법만을 적용하였을 경우보다 장시간 귀환 기법 방법에 단시간 귀환 기법을 적용하였을 경우에 우수한 성능 개선이 있음을 확인할 수 있었다.

• 터널과지하공간
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• 제4권2호
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• pp.132-143
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• 1994

Many methods and techniques to reduce ground vibrations are well known. Some of them are to adopt electric millisecond detonators with a sequential blasting machine or an initiating system with an adequate number of delay intervals. The types of electric detonators manufactured in korea include instantaneous, decisecond and millisecond delays but numbers of delay intervals are only limited from No.1 to No.20 respectively. It is not sufficient to control accurately millisecond time with these detonators in tunnel excavation. Sequential fire time refers to adding an external time delay to a detonators norminal firing time to obtain sequential initiation and it is determined by sequential timer setting. To reduce the vibration level, sequential blasting machine(S.B.M) with decisecond detonators was adopted. A total of 134 blasts was recorede at various sites. Blast-to-structure distances ranged from 20.3 to 42.0 meter, where charge weight varied from 0.24 to 0.75 kg per delay. The results can be summarized as follow: 1. The effects of sequential blasting machine on the vibration level are discussed. The vibration level by S.B.M are decreased approximately 14.38~18.05% compare to level of conventional blasting and cycle time per round can be saved. 2. The empirical equations of particle velocity were obtained in S.B.M and conventional blasting. V=K(D/W1/3)-n, where the values for n and k are estimated to be 1.665 to 1.710 and 93.59 to 137 respectively. 3. The growth of cracks due to vibrations are found but the level fall to within allowable value.

• 농약과학회지
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• 제2권3호
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• pp.45-51
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• 1998

방향족 고리로서 2-pyridyl이나 phenyl group이 치환($R_{1}$)된 비스 방향족 ${\alpha},{\beta}$-불포화 케톤 기질 유도체중 치환($R_{2}$) phenyl backbone의 변화에 따른 벼도열병균(Pyricularia oryzae)과 토마토 역병균(Phytophtora infestans) 및 보리횐가루병균(Erysiphe graminis)에 대한 항균활성과 물리화학 파라미터들 사이의 정량적 구조-활성관계(QSAR)를 검토하였다. phenyl 치환체, $1{\sim}11$의 벼도열병군에 대한 항균활성은 전자밀게에 의한 공명효과(R<0)와 소수성(${\pi}$>0), 토마토역병균의 경우에는 적정값의 STERIMOL 파라미터인 치환기의 길이$((L_{1})_{opt.}=5.69({\AA}))$ 그리고 보리흰가루병균은 적정값의 소수성((${\pi})_{opt.}=0.38$)에 의존적이었다. 또한, 2-pyridyl 치환체, $12{\sim}28$에 있어서 벼도열병균$(M_{R})_{opt.}=39(cm^{3}/mol)$과 토마토 역병$(M_{R})_{opt.}=8.04(cm^{3}/mol)$은 적정값의 분자굴절상수($M_{R}$)와 Taft의 입체효과(Es), 그리고 보리 흰가루병균의 경우에는 Es와 정전위(EP), 그리고 LUMO 에너지(e.v)가 항균활성에 각각 영향을 미치는 요인이었다. 그리고 보리흰가루병균의 경우 두 치환체들의 항균활성 관계는 서로 비례관계를 보이는 경향이었다.