• 한국패류학회지
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• 제17권2호
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• pp.71-78
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• 2001

1995년 4월부터 1996년 3월까지 충청남도 보령시 연안에 서식하는 키조개를 총 701마리 채집하여 성장을 조사하였다. 1. 키조개의 패각에 나타나는 윤문은 년1회 형성되며 주 윤문형성시기는 6월에서 7월로 조사되었다. 2. 초륜 형성기간은 12개월(만 1년)로 나타났다. 3. 각고 (SH)와 총중량 (TW)간의 관계는 TW=5.906$\times$$10^{-3}$S $H^{3.3844}$이었으며, 각장 (SL)과 각고(SH)간의 관계는SL=0.5277SH+0.0934이고, 각장 (SL)과 각폭(SW)간의 관계는 SW=0.2681SH-1.3757였다. 4. 연령(t)에 대한 각고 (SH)와 총중량 (TW)의 Bertalanffy 성장식은 SHt=30.99(1-e-$^{0.321}$2(t+0.9653)/이고 (Fig.11) TWt=657.94(1-e-$^{0.321}$2(t+0.9653/)$^{3.3844}$(Fig. 12)였다.)였다.

• 한국패류학회지
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• 제23권1호
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• pp.17-23
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• 2007

2004년 10월부터 2005년 11월까지 전라북도 고창군 주진천에 서식하는 쇄방사늑조개의 서식지 환경과 성장을 조사하였다. 서식지의 월별 수온은 $4.6-29.3^{\circ}C$로 나타났으며, 1월에 가 장 낮았고, 8월에 가장 높았다. 지온은 $2.6-29.4^{\circ}C$로 나타났으며 수온과 비슷하게 1월과 2월에 낮았고 8월에 가장 높았다. 월별 염분은 2.3-20.2 psu로 평균 $8.21\;{\pm}\;4.77\;psu$였다. 쇄방사늑조개의 패각에 나타나는 윤문은 년 1회 형성되며, 주된 윤문 형성 시기는 10-12월임을 확연할 수 있었다. 초륜의 형성 기간은 약 5개월 (0.42년) 으로 나타났으며, 각장 (SL) 과 각고 (SH) 간의 관계는 SH = 0.4352 SL + 0.5642 ($R^2\;=\;0.978$) 이고, 각장과 각폭 (SW) 간의 관계는 SW = 0.4352 SL - 0.5675 ($R^2\;=\;0.957$) 이며, 각장과 전중량 (TW) 간의 관계는 $TW\;=\;6.999\;{\times}\;10^{-5}\;SL^{3.2542}\;(R^2\;=\;0.975)$ 로 나타났다. 연령 (t) 에 대한 각장 (SL) 의 Bertalanffy 성장식은 $SL_t\;=\;30.77\;[1-e^{-0.4572(t+0.7371)}]$였으며, 전중량 (TW) 의 Bertalanffy 성장식은 $TW_t\;=\;4.87\;[1-e^{-0.4572(t+0.7371)}]^{3.2542}$로 추정되었다.

• 한국해양학회지:바다
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• 제11권4호
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• pp.152-157
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• 2006

2004년 4월부터 2005년 3월까지 전라북도 김제시 심포면 갯벌에 서식하는 백합의 연령과 성장을 조사하였다. 백합의 패각에 나타나는 윤문은 년 1회 형성되며, 주된 윤문 형성시기는 2월$\sim$4월임을 확인할 수 있었다. 초륜의 형성기간은 약 6개월(0.5년)로 나타났으며, 각장(SL)과 각고(SH)간의 관계는 SH=0.8103 SL + 0.5145$(R^2=0.991)$이고, 각장과 각폭(SW)간의 관계는 SW=0.4897 SL + 0.0315 $(R^2=0.976)$이며, 각장과 전중량(TW)간의 관계는 $TW=2.9195\times10^{-4}\;SL^{2.9547}\;(R^2=0.991)$로 나타났다. 연령 (t)에 대한 각장(SL)의 Bertalanffy 성장식은 $SL_t=104.9(l-e^{-0.2235(t+0.7677)})$였으며, 전중량(TW)의 Bertalanffy 성장식은 $TW_t=280.8(l-e^{-0.2235(t+0.7677)})^{2.9547}$로 추정되었다.

• 한국수자원학회:학술대회논문집
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• 한국수자원학회 2005년도 학술발표회 논문집
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• pp.792-796
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• 2005

The methods of times series analysis have been recognized as important tools for assisting in solving problems related to the management of water resources. Especially, After more than 40 years the so-called Hurst effect remains an open problem in stochastic hydrology. Until now, its existence has been explained fly R/S analysis that roots in early work of the British hydrologist H.E. Hurst(1951). Today, the Hurst analysis is mostly used for the hydrological studies for memory and characteristics of time series and many methodologies have been developed for the analysis. So, there are many different techniques for the estimation of the Hurst exponent(H). However, the techniques can produce different characteristics for the persistence of a time series each other. We found that DFA is the most appropriate technique for the Hurst exponent estimation for both the shot term memory and long term memory. We analyze the SOI(Southern Oscillations Index) and 6 tree-ring series for USA sites by means of DFA and the BDS statistic is used for nonlinearity test of the series. From the results, we found that SOI series is nonlinear time series which has a long term memory of H=0.92. Contrary to earlier work of Rao(1999), all the tree- ring series are not random from our analysis. A certain tree ring series show a long term memory of H=0.97 and nonlinear property. Therefore, we can say that the SOI and tree-ring series may show long memory and nonlinearity.

• 한국제4기학회지
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• 제17권2호
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• pp.157-159
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• 2003

Much of northern Asia is lacking in high-resolution palaeoclimatic data coverage. This vast region thus represents a sizeable gap in data sets used to reconstruct hemispheric-scale temperature trends for the past millennium. To improve coverage, we present a regional-scale composite of four tree-ring width records of Siberian pine and Siberian larch from temperature-sensitive alpine timber-line sites in Mongolia. The chronologies load closely in principal components analysis (PCA) with the first eigenvector accounting for over 53% of the variance from ad 1450 to 1998. The 20-year interval from 1974 to 1993 is the highest such growth period in this composite record, and 17 of the 20 highest growth years have occurred since 1946. Thus these trees, unlike those recently described at some northern sites, do not appear to have lost their temperature sensitivity, and suggest that recent decades have been some of the warmest in the past 500 years for this region. There are, however, comparable periods of inferred, local warmth for individual sites, e.g., in 1520-1580 and 1760-1790. The percent common variance between chronologies has increased through time and is highest (66.1%) in the present century. Although there are obvious differences among the individual chronologies, this result suggests a coherent signal which we consider to be related to temperature. The PCA scores show trends which strongly resemble those seen in recent temperature reconstructions for the Northern Hemisphere, very few of which included representation from Eurasia east of the Ural Mountains. The Mongolia series therefore provides independent corroboration for these reconstructions and their indications of unusual wanning during the twentieth century.

• Nuclear Engineering and Technology
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• 제48권2호
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• pp.533-544
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• 2016

This paper provides a reference to determine the seal performance of metallic O-rings for a reactor pressure vessel (RPV). A nonlinear elastic-plastic model of an O-ring was constructed by the finite element method to analyze its intrinsic properties. It is also validated by experiments on scaled samples. The effects of the compression ratio, the geometrical parameters of the O-ring, and the structure parameters of the groove on the flange are discussed in detail. The results showed that the numerical analysis of the O-ring agrees well with the experimental data, the compression ratio has an important role in the distribution and magnitude of contact stress, and a suitable gap between the sidewall and groove can improve the sealing capability of the O-ring. After the optimization of the sealing structure, some key parameters of the O-ring (i.e., compression ratio, cross-section diameter, wall thickness, sidewall gap) have been recommended for application in megakilowatt class nuclear power plants. Furthermore, air tightness and thermal cycling tests were performed to verify the rationality of the finite element method and to reliably evaluate the sealing performance of a RPV.

• 한국초전도ㆍ저온공학회논문지
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• 제11권1호
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• pp.49-54
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• 2009

This paper presents the numerical simulation results on the moving type electrodynamic suspension (EDS) simulator and static type EDS simulator using high-Tc superconducting (HTS) levitation magnet. The levitation force of the EDS system is formed by the reaction between the moving magnet and the fixed ground conductor. The possible two ways to simulate the EDS system were simulated in this paper by using finite element method (FEM). The first way was the moving type simulator which consists of the fixed HTS magnet and the moving ground conductor. The second way was the static type simulator which consists of the fixed magnet, the fixed ground conductor and the ac current supply system. To verify the characteristics of high speed EDS system with the moving type simulator heavy, large and fast moving ground conductor is needed. The static type simulator can get the characteristics of the high speed EDS system by applying equivalent ac current to velocity, therefore it does not need large moving part. The static type EDS simulator, which can consist of an HTS magnet, the fixed ground conductor(s), an AC power supply and the measuring devices, also test the effect of the shape of the ground conductor easily. The plate type ground conductor made stronger levitation force than ring type ground conductor. Although the outer diameter 335 mm ring type ground conductor (Ring3) was larger than the outer diameter 235 mm ground conductor (Ring2), the levitation force by Ring2 was stronger than that by Ring3. From the calculation results on this paper, the consideration of the magnetic flux distribution according to the levitation height should be included in the process of the ground conductor design.

• 대한화학회지
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• 제9권3호
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• pp.134-141
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• 1965

니코틴 二沃化水素酸鹽의 結晶은 直角非等軸結晶係(料方晶係)에 屬하며 空間群은 $p2_12_12_1$이다. 單位格子의 크기는 a=7.61, b=11.01 및 e=17.27${\AA}$이며 單位格子안에 들어있는 化學單位의 水는 4이다. 이 結晶의 構造를 X-線廻折法에 依하여 解析하였으며 R 値 ${\sum}{\mid}{\mid}F_{\circ}{\mid}-{\mid}F_c{\mid}{\mid}{\div}{\sum}{\mid}F_{\circ}{\mid}$ 가 $F_{orl}$와 $_{kol}$에 關하여 各各 0.16및 0.14의 값을 이룰 때까지 精密化 하였다. 原子間距離의 精密化를 試圖하지는 않았지만 피리딘 고리 안의 C-C 및 C-N의平均距離는 各各 1.40 및 $1.35{\AA}$의 값을 가진다. 피리딘 고리 內의 各原子는 實驗誤差內에서 同一平面上에 있으며 피롤리딘 고리에서는 $C_6,\;C_7,\;C_8$및$N_2$原子는 大略 同一平面上에 있으나 $C_9$는 이 平面으로 부터 約0.22${\AA}$ 떨어져있다. 피리딘 고리의 平面과 $C_6,\;C_7,\;C_8$및 $N_2$가 이루는 平面의 各法線은 約 $94^{\circ}$를 이루고 있다. 이코틴 二沃化水素酸鹽의 한 分子內의 두個의 요오드 原子中 한개는 피리딘 고리의 窒素原子와 $3.55{\AA}$의 距離로 連結되여 있으며 다른 한개는 피콜리딘 고리의 窒素原子 와 $3.58{\AA}$의 距離로 連結되여 있다. 結晶內에서 各 分子는 Van der Waals force로 서로 接燭되여 있다.

• 대한수학회논문집
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• 제39권1호
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• pp.31-43
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• 2024

Let $R_e\,=\,\frac{{\mathbb{F}}_{p^m}[u]}{{\langle}u^e{\rangle}}$, where p is a prime number, e is a positive integer and u^e = 0. In this paper, we first characterize the structure of cyclic codes of length p^s over R_e. These codes will be classified into 2^e distinct types. Among other results, in the case that e = 4, the torsion codes of cyclic codes of length p^s over R₄ are obtained. Also, we present some examples of cyclic codes of length p^s over R_e.

• Progress in Superconductivity
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• 제2권2호
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• pp.86-91
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• 2001

Temperature dependences of the unloaded Ｑ(Ｑ$_{0}$) and the resonant frequency ( $f_{0}$) of YB $a_2$C $u_3$ $O_{7-{\delta}}$ (YBCO) microstrip ring resonators and rutile-loaded cylindrical cavity resonators were measured at low temperatures. Dc magnetron-sputtered YBCO films grown on Ce $O_2$-buffered r-cut sapphire (CbS) substrates were used fur this purpose. The surface resistances ( $R_{s}$) of YBCO films measured by both a microstrip ring resonator and a TE $01\delta$/ mode rutile-loaded cylindrical cavity resonator are compared with each other. It turned out that the values of $R_{s}$ measured by the microstrip resonator technique are comparable to those by the rutile-loaded resonator technique at temperatures lower than ~50 K. However, above 50 K, the $R_{s}$ measured by the microstrip resonator technique appeared higher according to the temperature. Our results show that the current crowding effects near the edge of a microstrip resonator become more significant at temperatures near the critical temperature.emperature.e.e.e.e.e.e.