• 국제학술발표논문집
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• The 1th International Conference on Construction Engineering and Project Management
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• pp.796-801
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• 2005

Time management is one of the critical tasks in project management. Based on the theories of total quality management, this authors presented a project time management method, total time management (TTM), so as to facilitate highway project time management. This paper discussed the four fundamental characteristics of TTM: total factors management, staff management, project life cycle management, and Plan-Do-Check-Action (PDCA) cycle management. Now, most managers use computer software to manage the project. In order to make the theory of TTM more executable, the authors develop a project time management system suitable for TTM. This paper presents this time management system's analysis processes including system requirement, key functions etc..

• 한국환경농학회지
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• 제25권4호
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• pp.346-351
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• 2006

시설 유기농 토마토 생산을 위한 녹비 토양환원 효과를 조사하기 위하여 여름 휴한기 동안 페레니얼라이그라스, 수단그라스, 콩 등 3종의 녹비를 재배한 후 토양에 환원 하였다. 녹비 토양환원 후, 후작물로서 토마토를 재배하였으며, 녹비토양환원에 따른 토마토 생육 및 수량, 양분이용율, 양분수지량을 조사하였다. 녹비 토양환원 후 토마토의 생육 및 생산성은 콩과 같은 두과작물을 녹비로 활용 시 현저히 증가하였다. 반면에 페레니얼라이그라스는 여름철 고온에 따른 하고 현상으로 생육이 부진하였고, 수단그라스는 녹비 수확량은 많았으나 높은 C/N율로 인해 토마토의 수량을 감소시켰다. 콩을 녹비로 토양환원 시 후작물 토마토의 수량은 화학비료를 처리한 관행과 비교할 때 현저한 차이가 없었고, 토양 내 질소 수지량은 양의 값을 보였다. 결과적으로 수단그라스 녹비는 후작물 토마토의 생산성을 크게 감소시킨 반면, 콩 녹비는 관행수준의 토마토 수량을 얻을 수 있을 뿐 아니라 토마토 재배에 필요한 양분수지를 충족시킬 수 있어 수단그라스에 비해 우수한 녹비로 판단된다.

• The Korean Journal of Physiology and Pharmacology
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• 제2권4호
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• pp.493-501
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• 1998

The most significant direct role of estrogen in vivo is its ability to elicit receptor-mediated cellular proliferation in mammalian target tissues. However, the mechanism by which exogenously added estrogen causes the neoplastic transformation of renal cortical cells is yet to be uncovered. The present study was designed to evaluate interaction of $17{\beta}-estradiol\;(E_2)$ with epidermal growth factor (EGF) and insulin-like growth factor-I (IGF-I) on proliferation and $P_i$ uptake in primary cultured rabbit renal proximal tubular cells in phenol red-free, hormonally defined-medium. $[^3H]-thymidine$ incorporation increased markedly by about 133% and 141% more in the presence of $10^{-9}\;and\;10^{-6}\;M\;E_2$, respectively, than that of control. Cell count was 162% and 143% greater in the presence of $10^{-9}\;and\;10^{-6}\;M\;E_2$ , respectively, compared with control. Among all time points examined, there was an increase in $[^3H]-thymidine$ incorporation in the presence of $10^{-9}\;M\;E_2$ at day 9 or 13, respectively. However, $E_2$ ($10^{-9}\;M$) significantly drove up cell count to 160% of that of control at day 13, while it had a slight but statistically insignificant effect at day 9. $E_2-induced$ stimulation of $[^3H]-thymidine$ incorporation was completely reversed by $E_2$ antagonists (progesterone or tamoxifen). $E_2$ ($10^{-9}\;M$) or EGF ($10^{-8}\;M$) significantly stimulated $[^3H]-thymidine$ incorporation by 144% and 154% of control. $E_2$ plus EGF was synergistic on $[^3H]-thymidine$ incorporation (204% of control), while $E_2$ plus IGF-I showed a slight but no significant synergistic effect. Cell number also displayed similar pattern. $E_2$ ($10^{-9}\;M$) significantly stimulated $P_i$ uptake to 134% of control. $E_2$-induced stimulation of $P_i$ uptake was partially reversed by $E_2$ antagonists. EGF or IGF-I ($10^{-8}\;M$) significantly also increased $P_i$ uptake to 132% or 129% of control. $E_2$ plus EGF had synergistic effect on $P_i$ uptake, while $E_2$ plus IGF-I did not. In conclusion, $E_2$ may act not only directly interaction with its receptors but also indirectly as a modulator of EGF in proliferation and $P_i$ uptake of primary cultured rabbit renal proximal tubular cells.

• Restorative Dentistry and Endodontics
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• 제18권1호
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• pp.156-172
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• 1993

The purpose of this study was to evaluate for the cytotoxicity of root canal sealers - Tubliseal, N2, AH26, and Sealapex - on fibroblasts cultivated from human periodontal ligament. Succinate dehydrogenase activity test and $^{51}Cr$ release test were performed to evaluate the shortterm cytotoxicity. According to l,3 and 6 days vital cell count and $^{14}C$-leucine incorporation rate to fibroblasts were evaluated. The results of this study were as follows: 1. In the test of SDH activity by millipore filter method, Sealapex showed mild cytotoxicity but Tubliseal, N2 and AH26 showed severe cytotoxicity. 2. In $^{51}Cr$ release test, Tubliseal was the most cytotoxic sealer tested, and rank ordered the relative cytotoxicity of the other sealers tested as follows: AH26, N2, Sealapex. 3. In the test of viable cell count, cytotoxicity in Tubliseal was continued because vital cell number reduced with time. Because vital cell was not showed in N2 and AH26 at 1 day, it was recognized that N2 and AH26 exhibited severe cytotoxicity. In Sealapex, vital cell number increased remarkably with time, so it showed that cytotoxicity decreased with time. 4. In $^{14}C$-leucine incorporation rate test, protein sythesis was not produced in Tubliseal, N2 and AH26 after 3 days, it showed that cytotoxicity in Tubliseal, N2 and AH26 was severe. Although protein synthesis in Sealapex decreased with time, it continued after 6 days. Therefore Sealapex has been exhibited mild cytotoxicity.

• 콘크리트학회논문집
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• 제11권4호
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• pp.3-11
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• 1999

The creep characteristics of concrete under tensile stress has been usually assumed to have the same characteristics as that under compressive stress in the time-dependent analysis of concrete structures. However, it appears from the recent experimental studies that tensile creep behavior is much different from compressive one. In particular, high sustaining tensile stress may cause time-dependent cracking and thus lead to tensile failure. It is, therefore, necessary to model the tensile creep behavior accurately for realistic time-dependent analysis of concrete structures. The present paper to have been focused to suggested more realistic model for the tensile creep behavior of concrete. The models are compared with tensile creep test data available in the literature. The proposed model may allow more refined analysis of concrete structures under time-dependent loading.

• Ecology and Resilient Infrastructure
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• 제3권1호
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• pp.1-7
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• 2016

최근 하천복원 사업은 하천의 이수 및 치수 기능과 함께 생태적 기능을 고려한 방향으로 진행되고 있다. 생태적 건강성과 다양성이 증대된 하천으로의 복원을 위해서는 하천 내 제방과 같은 종적구조물로 의해 차단된 공간에서의 수리수문 연결성 회복이 중요하다. 본 연구에서는 차단된 공간에서의 생태적 연결성 분석에 필요한 수리수문자료의 제공을 위한 첫번째 단계로써 강우에 의한 유역유출 및 하도흐름 해석이 동시에 가능한 1차원 수치모형을 개발하였고, 이를 청미천 유역에 적용하였다. 수치해석 결과는 실측 자료 및 타 모형의 수치해석 결과와 비교하였고, 그 결과 잘 일치함을 알 수 있었다. 본 연구의 결과는 생태적 변화를 예측할 수 있는 자료의 제공을 위해 장기적인 수리수문분석이 가능하도록 보완될 예정이다.

• 한국결정학회지
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• 제7권1호
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• pp.81-87
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• 1996

석영 boat를 반응용기로 쓰는 수평 Bridgman 법에서, GaAs 단결정에 유입되는 Si 농도를 Ga-As 계의 상평형에 근거한 열역학적 평형을 가정하여 성장방법 별로 계산하였고, Hall 측정에 의한 전자 농도 측정치와 비교하였다. 단일 온도대역 수평 Bridgman(1-T HB) 법의 경우 Si 농도의 계산치가 5.3 ×10 15(atoms/cm3)인데 비해 실험치는 9.8 ×10 15(/cm3) 이었고, 이중 온도대역 수평 Bridgman(2-T HB) 법에서는 계산치가 1.1 ×10 16(atoms/cm3), 측정치가 1.5 ×10 16(/cm3) 인 것으로 각각 나타났다. 한편 1-T나 2-T HB 법에 비하여 성장시간이 절반 정도인 VGF(vertical gradient freeze) 방법의 경우 이론치와 실험치가 비교적 일치 하였고 그 값은 (6∼8) ×10 15 (atoms/cm3)인 것으로 나타났다.

• 한국자원식물학회지
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• 제28권2호
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• pp.271-278
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• 2015

생강연작재배지 토양에 녹비작물의 재배가 토양 양분의 변화와 뿌리썩음병원균 경감효과를 알기위해 헤어리베치, 크림손클로버, 오차드글라스를 80일간 재배 후, 토양에 환원하여 토양분석 및 real-time PCR 분석한 결과는 다음과 같다. 녹비작물의 생육은 크림손클로버가 가장 좋았으며, 질수흡수량은 크림손클로버가 가장 높게 나타났으며, 토양의 인산함량은 오차드글라스가 가장 낮게 나타났다. T-N 함량은 헤어리벳치 > 크림손클로버 > 오차드글라스 순으로 나타났다. 또한 토양 내 뿌리썩음 병원균 밀도분석을 위해 Pythium zingiberum 균 특이 5.8S rDNA를 이용하여 real-time PCR 분석한 결과 헤어리베치, 오차드그라스 및 크림손클로버 처리의 Ct값은 대조구보다 낮게 나타났다. 이상의 결과를 요약해볼 때 생강연작재배지에서 녹비처리 후 토양은 대조구에 비해 EC가 감소되고, 몇 몇 무기성분은 증가하였으며, 뿌리썩음 병원균 밀도는 감소하였다.

• Animal cells and systems
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• 제1권2호
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• pp.341-344
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• 1997

Receptor-mediated endocytosis has been suggested for a stage-specific transport mechanism of vitellogenin into the oocytes of a sabellid poly chaete, Pseudopotamilla occelata. Membrane proteins of oocytes of three size classes, including small (30-70 $\mu\textrm{m}$ in diameter), intermediate (70-140 $\mu\textrm{m}$ in diameter) and large (180-200 $\mu\textrm{m}$ in diameter), showed a atage-specific variation. Coelomic fluid proteins (CP), ass$\mu\textrm{m}$ed to be vitellogenin, consists of several proteins, which showed quite a different pattern from that of yolk proteins. Incorporation of $^{125}I$-CP into the oocytes of the intermediate size class almost linearly increases with time, showing a contrast to the pattern of the large size class, in which the incorporation is low and approaches a plateau, suggesting the vitellogenin transports by a regulated process only in the intermediate size class. Vitellogenin receptor proteins were identified to be 60 kDa and 68 kDa only in the intermediate size class by a ligand blotting test.

• 한국자기공명학회논문지
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• 제15권2호
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• pp.115-127
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• 2011

A newly developed cost-effective approach to prepare $^{15}N/^{13}C$-labeled protein for NMR studies is presented. This method has been successfully applied to isotopically labeling of PTK6 SH2 domain and MTH 1880 protein. The production method generates cell density using a growing media containing $^{15}NH_4Cl$, $^{12}C_6$-D-glucose. Following a doubling time period for unlabeled metabolite exhaustion and then addition $^{13}C_6$-D-glucose into a M9 growing media, the cells are induced. Our results demonstrate that in order to get full incorporation of $^{13}C$, the isotopes are not totally required during the initial growth phase before induction. The addition of small amounts of $^{13}C_6$-D-glucose to the induction phase is sufficient to obtain more than 95% incorporation of isotopes into the protein. Our optimized protocol is two-thirds less costly than the classical method using $^{13}C$ isotope during the entire growth phase.