• Geomechanics and Engineering
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• 제25권2호
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• pp.123-134
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• 2021

In this paper, the carbon fiber reinforced plastic (CFRP) grids embedded in polymer cement mortar (PCM) shotcrete (CFRP-PCM method) was conducted to repair the degraded tunnel linings with a cavity. Subsequently, the reinforcing effect of the CFRP-PCM method under different degrees of lining deterioration was quantitatively evaluated. Finally, the limit state design method of the M-N interaction curve was conducted to determine whether the structure reinforced by the CFRP-PCM method is in a safe state. The main results indicated that when the cavity is at the shoulder, the lining damage rate is more serious. In addition, the remarkably reinforcing effect on the degraded tunnel linings could be achieved by applying a higher grade of CFRP grids, whereas the optimization effect is no longer obvious when the grade of CFRP grids is too high (CR8); Furthermore, it is found that the M-N numerical values of the ten reinforcing designs of the CFRP-PCM method are distributed outside the corresponding M-N theoretical interaction curves, and these designs should be avoided in the corresponding reinforcing engineering.

• 한국방재학회 논문집
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• 제7권5호
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• pp.19-25
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• 2007

본 연구에서는 전주의 공칭강도를 계산하기 위해 이론적 방법에 의해 P-M상관도 프로그램을 개발하였다. 그리고 이를 바탕으로 기존 연구와 검증하고 전주의 공칭강도$(M_n)$를 산정하였다. 설계기준에 제시된 파괴강도$(M_r)$와 본 연구에서 산정한 전주의 공칭강도$(M_n)$를 비교 분석한 결과 현재 사용하고 있는 전주의 공칭강도가 설계기준$(M_r)$보다 작게 산정되었다. 따라서 공칭강도 증대를 위해 인장근/보강근의 지름 증가, 보강근의 개수 증가, 인장근의 위치변화, 전주의 두께 변화 등의 매개변수를 선정하여 선정된 매개변수를 고려한 전주의 공칭강도$(M_n)$를 설계기준의 공칭강도$(M_n)$와 비교 분석하였다.

• Earthquakes and Structures
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• 제22권3호
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• pp.219-230
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• 2022

Knowing that the variability of soil properties is an important source of uncertainty in geotechnical analyses, we will study in this paper the effect of this variability on the seismic response of a structure within the framework of Soil Structure Interaction (SSI). We use the proposed and developed model (N2-ISS, Mekki et al., 2014). This approach is based on an extension of the N2 method by determining the capacity curve of the fixed base system oscillating mainly in the first mode, then modified to obtain the capacity curve of the system on a flexible basis using the concept of the equivalent nonlinear oscillator. The properties of the soil that we are interested in this paper will be the shear wave velocity and the soil damping. These parameters will be modeled at first, as independent random fields, then, the two parameters will be correlated. The results obtained showed the importance of the use of random field in the study of SSI systems. The variability of soil damping and shear wave velocity introduces significant uncertainty not only in the evaluation of the damping of the soil-structure system but also in the estimation of the displacement of the structure and the base-shear force.

• 한국정밀공학회지
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• 제24권3호
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• pp.140-146
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• 2007

To understand adhesive phenomena, we need to get force curve between two surfaces. And it is said that high stiffness force analysis system is needed to get precise force curve and more information of the surfaces. Usually the stiffness of the force measurement system is under the order of 10N/m. The stiffer force measurement system, however, results in more information on the surface, because higher stiffness lead to the wider range of force curves, secondly because the force curve obtained through the stiffer one describes more precise relationship between relative tip-sample separation and interaction force. In this paper, considering for stiffness and resolution, the cantilever was designed and we made adhesion force measurement apparatus with high stiffness and high resolution, so we measured adhesive force between Ag-ball and wafer.

• 한국자기학회지
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• 제11권5호
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• pp.232-238
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• 2001

Nano결정립 N $d_2$F $e_{14}$B+F $e_3$B 복합상 자성 압분체의 탈자화 현상을 자기특성 변화 및 $\delta$M측정에 의해 분석하였다. 초기 조성 N $d_4$F $e_{73.5}$ $Co_3$H $f_{0.5}$G $a_{0.5}$ $B_{18.5}$의 최대자기에너지적은 리본상태에서 14 MGOe, 분말 압분체에서 6.5 MGOe로 크게 감소하였다. 이러한 현상은 복합상의 리본상태에서 존재하는 교환상호작용력이 분말 압분체에서는 나타나지 않고, 정자장 작용에 의한 탈자화로 인해 잔류자속밀도가 크게 감소한 결과이다. 이는 급냉리본(bulk) 보다 압분체상태에서 정자장 상호작용력이 교환상호작용력보다 더 크게 작용하는 결과로 해석된다. 또한, 자성체 리본을 분쇄하는 과정에서 발생한 응력도 자기특성을 감소시키는 요소임을 확인하였다.하였다.하였다.

• 약학회지
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• 제34권4호
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• pp.224-237
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• 1990

A single uniform population of specific, saturable, high affinity binding site of $[^3H]QNB$ guinuclidinyl benzilate(QNB) was identified in the rat cerebral microsomes. The Kd value(37.2 pM) for $[^3H]QNB$ calculated from the kinetically derived rate constants was in agreement with the Kd value(48.9 pM) determined by analysis of saturation isotherms at various receptor concentrations. Dimenhydrinate(DMH), histamine $H_1-blocker$, increased Kd value for $[^3H]QNB$ QNB without affecting the binding site concentrations and this effect resulted from the ability of DMH to slow $[^3H]QNB-receptor$ association. Pirenzepine inhibition curve of $[^3H]QNB$ binding was shallow(nH = 0.52) indicating the presence of two receptor subtypes with high ($M_1-site$) and low($M_2-site$) affinity for pirenzepine. Analysis of these inhibition curves yielded that 68% of the total receptor populations were of the $M_1-subtype$ and the remaining 32% of the $M_2-subtype$. Ki values for the $M_1-$ and $M_2-subtypes$ were 2.42 nM and 629.3 nM, respectively. Ki values for $H_1-blockers$ that inhibited $[^3H]QNB$ binding varied with a wide range ($0.02-2.5\;{\mu}M$). The Pseudo-Hill coefficients for inhibition of $[^3H]QNB$ binding by most of $H_1-blockers$ examined except for oxomemazine inhibition of $[^3H]QNB$ binding were close to one. The inhibition curve for oxomemazine in competition with $[^3H]QNB$ was shallow(nH = 0.74) indicating the presence of two receptor populations with different affinities for this drug. The proportion of high and low affinity was 33:67. The Ki values for oxomemazine were $0.045{\pm}0.016\;{\mu}M$ for high affinity and $1.145{\pm}0.232\;{\mu}M$ for low affinity sites. These data indicate that muscarinic receptor blocking potency of $H_1-blockers$ varies widely between different drugs and that most of $H_1-blockers$ examined are nonselective antagonist for the muscarinic receptor subtypes, whereas oxomemazine might be capable of distinguishing between subclasses of muscarinic receptor.

• 콘크리트학회논문집
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• 제29권4호
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• pp.353-360
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• 2017

PHC말뚝을 보강한 CFP말뚝의 P-M 상관도를 통한 휨 모멘트 예측과 휨 실험 결과를 통해 P-M 계산법의 타당성과 CFP말뚝의 휨 성능을 평가한 실험 연구이다. 시험체는 PHC말뚝과 링형 합성 전단연결재 그리고 속채움 콘크리트를 기본으로 한 CFP말뚝과 1차 보강(말뚝 보강철근 H13-8ea), 2차 보강(내부 보강철근 H19-8ea)으로 제작된 시험체의 휨 실험 결과 CFP-N-N 시험체 대비 최고 하중이 46.4%, 103.9% 증대되었으며, 보강 철근량에 따른 연성능력 증대가 이루어졌다. 또한 CFP말뚝 설계법의 극한한계상태 예측값과 실험 결과값을 비교해 볼 때, 각 보강 단계별 1.23, 1.40배의 안전율을 확보하여 본 연구에서 제시한 설계법이 합리적인 것으로 판단된다.

• The Korean Journal of Physiology and Pharmacology
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• 제21권4호
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• pp.385-395
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• 2017

Vasoconstrictive properties of sympathomimetic drugs are the basis of their widespread use as decongestants and possible source of adverse responses. Insufficiently substantiated practice of combining decongestants in some marketed preparations, such are those containing phenylephrine and lerimazoline, may affect the overall contractile activity, and thus their therapeutic utility. This study aimed to examine the interaction between lerimazoline and phenylephrine in isolated rat aortic rings, and also to assess the substrate of the obtained lerimazoline-induced attenuation of phenylephrine contraction. Namely, while lower concentrations of lerimazoline ($10^{-6}M$ and especially $10^{-7}M$) expectedly tended to potentiate the phenylephrine-induced contractions, lerimazoline in higher concentrations ($10^{-4}M$ and above) unexpectedly and profoundly depleted the phenylephrine concentration-response curve. Suppression of NO with NO synthase (NOS) inhibitor $N^w$-nitro-L-arginine methyl ester (L-NAME; $10^{-4}M$) or NO scavanger $OHB_{12}$ ($10^{-3}M$), as well as non-specific inhibition of $K^+$-channels with tetraethylammonium (TEA; $10^{-3}M$), have reversed lerimazoline-induced relaxation of phenylephrine contractions, while cyclooxygenase inhibitor indomethacin ($10^{-5}M$) did not affect the interaction between two vasoconstrictors. At the receptor level, non-selective 5-HT receptor antagonist methiothepin reversed the attenuating effect of lerimazoline on phenylephrine contraction when applied at $3{\times}10^{-7}$ and $10^{-6}M$, but not at the highest concentration ($10^{-4}M$). Neither the 5-$HT_{1D}$-receptor selective antagonist BRL 15572 ($10^{-6}M$) nor 5-$HT_7$ receptor selective antagonist SB 269970 ($10^{-6}M$) affected the lerimazoline-induced attenuation of phenylephrine activity. The mechanism of lerimazoline-induced suppression of phenylephrine contractions may involve potentiation of activity of NO and $K^+$-channels and activation of some methiothepin-sensitive receptors, possibly of the 5-$HT_{2B}$ subtype.

• 대한화학회지
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• 제42권2호
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• pp.190-196
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• 1998

셀룰로스시료를 치환체로 만들지 않고 분자량 및 분자량분포를 결정하기 위한 새로운 시료처리 및 크기배제크로마토그래피방법을 확립하였다. 먼저 셀룰로스시료를 N-methylmorpholine N-oxide (NMMO)에 녹인 후 dimethyl sulfoxide (DMSO)에 희석함으로써 50/50(w) NMMO/DMSO에 녹은 약 0.1%의 시료용액을 만들었다. 컬럼으로는 글루코오스를 입힌 polydivinylbenzene 겔을 채운 크기배제크로마토그래피용 컬럼을 이용하였으며 용리액으로는 0.05M의 LiBr와 2.5%의 바탕용액을 포함하는 DMSO를 이용하였다.유속은 1 mL/min로 일정하게 유지하였고, DMSO의 점도를 낮추기 위해 컬럼을 포함하는 전체 시스템을 80$^{\circ}C$ 로 유지하였다. 0.05M의 LiBr를 가함으로써 SEC바탕선의 표류를 방지할 수 있었고 2.5%의 바탕용액을 가함으로써 시료와 컬럼충진물질 사이의 상호작용을 감소시키는 효과를 얻었다. 좁은 분포를 가지는 pullulan표준물질로부터 얻은 컬럼보정곡선을 이용하여 두 개의 I 펄프시료와 두 개의 셀룰로스 스펀지 시료의 평균분자량을 결정함으로써 펄프로부터 스펀지를 만드는 서로 다른 두 가지 공정에서의 셀룰로스 분자들의 분해정도를 결정, 비교할 수 있었다.

• 한국생물공학회:학술대회논문집
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• 한국생물공학회 2001년도 추계학술발표대회
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• pp.231-234
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• 2001

Biacore 바이오센서를 이용하여 재조합 HBsAg 를 정량분석하기 위해 CM5 칩 위에 anti-HBsAg polyclonal antibody를 저밀도 (2,304.2 RU)와 고밀도(17635.9 RU)로 고정화한 후 다양한 농도의 HBsAg를 흘려주어 각 농도별 sensorgram을 얻었다. 각 sensorgram으로부터 결합된 HBsAg의 질량을 구하여 액체 시료 내의 HBsAg의 농도 대 칩에 결합된 HBsAg의 질량 사이의 상관관계를 구한 결과 Langmuir 단일층 흡착 등온선과 매우 유사한 형태의 calibration curve를 얻었다. 약 40 ${\mu}g/m{\ell}$ 까지 선형 관계가 유지되었다. 이 calibration curve를 double-reciprocal plotting 하여 $RU_{max}$ 값을 각각 구한 뒤, 단위 질량의 고정화된 항체 당 결합된 HBsAg의 질량을 구한 결과 저밀도 칩에서 0.024, 고밀도 칩에서 0.023 으로 매우 유사한 결과를 나타내었다.