• Journal of Astronomy and Space Sciences
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• 제1권1호
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• pp.67-74
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• 1984

Photoelectric UBV light curves of AR lacertae made in one season during 1981-82 are presented. Although the shape of the light curves in the outside eclipses shows a strong distortion, the scatter of observations as well as phase coverage are better than those previously available. Fourier coefficients are derived from the V-light curve and the observed curve successfully rectified to the Russell model. Light curve solutions are computed and the geometrical and physical parameters of AR Lac are derived as $a_s$=0.182, $a_g$=0.341, j=$86^{circ}$3, $L_s$=0.372, $L_g$=0.628, k=0.53, $X_s$=0.85, $X_g$=0.4.

• Computers and Concrete
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• 제4권6호
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• pp.425-436
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• 2007

This study is mainly focused on applying Fuller's ideal gradation curve to theoretically design blended ratio of all solid materials of a reactive powder mortar (RPM), also known as reactive powder concrete (RPC), with the aid of error function, and then to study the effect of fly ash/slag on the performance of RPM. The solid particle is assumed to be spherical particles. Then, the void volume of paste ($V_{\nu}$) and the paste content with specific quality can be obtained. As conclusion, under Fuller's ideal grading curve, the amount of fly ash/slag mixture is higher than that with silica fume along due to it better filled the void within solid particle and obtains higher packing density.

• 대한치과교정학회지
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• 제23권4호
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• pp.485-492
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• 1993

Multiloop Edgewise Archwire(MEAW) is effective in relief the Curve of Spee in mandibular arch but up Sl down orthodontic elastics must be used with it. The purpose of this study was to analyse the effect of orthodontic elastics, like as up & down elastics, Class II elastics, and Class III elastics, and the effect of L loop in Multioop Edgewise Archwire. 1. Intrusive force of MEAW in anterior teeth was reduced and uprighting force in premolars was increased by up & down elastics. 2. Uprighting force was significintly increased with Class III elastics in multiple L loop arch wire. 3. The force of Class II elastics made molars tip mesially and Curve of Spee deep.

• 한국환경보건학회지
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• 제47권4호
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• pp.320-329
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• 2021

Background: Smoking exposure may be objectively assessed through specific biomarkers. The most common biomarker for smoking is cotinine concentration in urine, and setting an optimal cut-off point can accurately classify smoking status. Such a cut-off point for Korean adolescents has never been studied. Objectives: The aim of this study was to determine a cut-off point for urinary cotinine concentration for the discrimination of smoking in adolescents. Methods: Participants were adolescents aged 13~18 years who participated in the third cycle of the Korean National Environmental Health Survey. We used urine samples to confirm the level of cotinine concentrations. Smoking status was determined by self-reported questionnaire. We identified the optimal cotinine cut-off point for discriminating smoking status using receiver operating characteristic curve analysis. Results: Of the 904 participants, 28 (3.1%) were smokers, among whom 20 (71.4%) were male. The median urinary cotinine concentrations in smokers was 218 ㎍/L (male: 215 ㎍/L, female: 303 ㎍/L), and that in non-smokers was 1.31 ㎍/L (male: 1.46 ㎍/L, female: 1.18 ㎍/L). We found significant differences in urinary cotinine concentration according to smoking status and sex (p<0.001). Urinary cotinine concentrations performed well for identifying smoking adolescents [area under the curve: 0.954 (male: 0.963, female: 0.908)]. The cut-off that optimally distinguished smokers from non-smokers was 39.85 ㎍/L (sensitivity: 89.3%, specificity: 97.4%). Male [39.85 ㎍/L (sensitivity: 90.0%, specificity: 94.9%)] had a different optimal cut-off point than female [26.26 ㎍/L (sensitivity: 87.5%, specificity: 99.6%)]. Conclusions: This study determined a cut-off point for urinary cotinine of 39.85 ㎍/L (male: 39.85 ㎍/L, female: 26.26 ㎍/L) to distinguish smokers from non-smokers in adolescents.

• 대한수학회지
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• 제58권1호
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• pp.123-132
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• 2021

Let K be a number field and L a finite abelian extension of K. Let E be an elliptic curve defined over K. The restriction of scalars ResKLE decomposes (up to isogeny) into abelian varieties over K $$Res^L_KE{\sim}{\bigoplus_{F{\in}S}}A_F,$$ where S is the set of cyclic extensions of K in L. It is known that if L is a quadratic extension, then AL is the quadratic twist of E. In this paper, we consider the case that K is a number field containing a primitive third root of unity, $L=K({\sqrt[3]{D}})$ is the cyclic cubic extension of K for some D ∈ K×/(K×)3, E = Ea : y2 = x3 + a is an elliptic curve with j-invariant 0 defined over K, and EaD : y2 = x3 + aD2 is the cubic twist of Ea. In this case, we prove AL is isogenous over K to $E_a^D{\times}E_a^{D^2}$ and a property of the Selmer rank of AL, which is a cubic analogue of a theorem of Mazur and Rubin on quadratic twists.

• 수산해양기술연구
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• 제29권3호
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• pp.177-182
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• 1993

In order to estimate the mesh selectivity master curves and the optimum mesh size, experiments were made by the cover net method with the cod-ends of the five different the opening mesh sizes(51.2mm, 70.2mm, 77.6mm, 88.0mm and 111.3mm). After that 163 hauling were performed and there by investigated, on the training vessel Saebada in the Southern Korean Sea and East China Sea from June 1991 to August 1992. In this report, the mesh selectivity master curves were fitted by using logistic function(S=1/(1+exp super(-(aR+b))), R=(L-L sub(0))/(M-M sub(0)) and the optimum mesh sizes were estimated from each master curve. In this case, a and b are the selection parameters, M is the mesh size of each experimental cod-end. L is body length, L sub(0) and M sub(0) is the distance from the coordinate origine to intersection of linear regression between 25% and 50% selection length. The results obtained are summarized as follows; 1. Trachurus japonicus: Mesh selectivity master curve parameters: a and b were 2. 25, -4.73 respectively and optimum mesh size was estimated to be 79.3mm. 2. Trichiurus lepturus: Mesh selectivity master curve parameters: a and b were 0.81, -3.17 respectively and optimum mesh size was estimated to be 64.5mm. 3. Photololigo edulis: Mesh selectivity master curve parameters: a and b were 1.30m, -4.10 respectively and optimum mesh size was estimated to be 89.9mm. 4. Todarodes pacificus: Mesh selectivity master curve parameters: a and b were 1. 35, -3.45 respectively and optimum mesh size was estimated to be 89.4mm.

• 대한수학회지
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• 제37권3호
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• pp.359-369
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• 2000

Let X be an integral Gorenstein projective curve with g:=pa(X) $\geq$ 3. Call $G^r_d$ (X,**) the set of all pairs (L,V) with L$\epsilon$Pic(X), deg(L) = d, V $\subseteq$ H^0$(X,L), dim(V) =r+1 and V spanning L. Assume the existence of integers d, r with 1 $\leq$ r$\leq$ d $\leq$ g-1 such that there exists an irreducible component, , of $G^r_d$(X,**) with dim($\Gamma$) $\geq$ d - 2r and such that the general L$\geq$$\Gamma$ is spanned at every point of Sing(X). Here we prove that dim( ) = d-2r and X is hyperelliptic.

• 대한수학회논문집
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• 제33권1호
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• pp.237-245
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• 2018

For every interval [a, b], we denote by $({\bar{x}}_A,{\bar{y}}_A)$ and $({\bar{x}}_L,{\bar{y}}_L)$ the geometric centroid of the area under a catenary curve y = k cosh((x-c)/k) defined on this interval and the centroid of the curve itself, respectively. Then, it is well-known that ${\bar{x}}_L={\bar{x}}_A$ and ${\bar{y}}_L=2{\bar{y}}_A$. In this paper, we fix an end point, say 0, and we show that one of ${\bar{x}}_L={\bar{x}}_A$ and ${\bar{y}}_L=2{\bar{y}}_A$ for every interval with an end point 0 characterizes the family of catenaries among nonconstant $C^2$ functions.

• 대한기계학회논문집A
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• 제38권3호
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• pp.329-335
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• 2014

U 자형 전자석 하나로 부상력과 안내력을 동시에 얻는 중 저속 자기부상열차는 안내제어기 없이 곡선을 주행한다. 때문에 곡선, 특히 곡률반경이 매우 작은 곡선 주행 시에 차량이 레일과 물리적 접촉을 방지하기 위해서는 곡선형상의 결정이 세심하게 이루어져야 한다. 특히 완화곡선의 형상이 중요하다. 본 논문에서는 완화곡선 선로를 구성하는 형상 매개변수들의 차량 안내 성능에의 영향도를 분석하는데 목적이 있다. 이를 위하여 차량, 전자석, 부상제어기, 곡선가이드웨이가 통합된 3 차원 자기부상열차 다물체 동역학 모델을 개발하였고, 개발된 모델을 이용하여 곡선형상을 구성하는 매개변수 연구를 수행하였다. 연구 결과는 곡선형상의 결정이나 차량의 대차구조를 설계하는데 이용이 가능하다고 할 수 있다.

• 한국환경과학회지
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• 제23권3호
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• pp.511-520
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• 2014

The MFFn(Mass first flush), EMCs(Event mean concentrations) and runoff loads were analyzed for various rainy events(monitoring data from 2011 to 2012) in transportation area(rail road in station). The pollutant EMCs by volume of stormwater runoff showed the BOD5 9.6 mg/L, COD 29.9 mg/L, SS 16.7 mg/L, T-N 3.271 mg/L, T-P 0.269 mg/L in the transportation areas(Railroad in station). The average pollutant loading by unit area of stormwater runoff showed the BOD5 $27.26kg/km^2$, COD $92.55kg/km^2$, SS $50.35kg/km^2$, T-N $10.13kg/km^2$ and T-P $10.13kg/km^2$ in the transportation areas. Estimated NCL-curve(Normalized cumulated-curve) was evaluated by comparison with observed MFFn. MFFn was estimated by varying n-value from 10% to 90% on the rainy events. The n-value increases, MFFn is closed to '1'. As time passed, the rainfall runoff was getting similar to ratio of pollutants accumulation. The result of a measure of the strength of the linear relationship between observed data and expected data under model was good.