• 한국수산과학회지
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• 제8권2호
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• pp.47-60
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• 1975

자원해석은 일반적으로 시계열적 견지에 입각하고 있으나, 본 연구에서는 단면적인 견지에서, 2년간의 자원변동을 극수적인 관계에서 파악하여 자원해석을 하였으며, 이것으로 각년의 가입량을 추정하는 방법 시도하였다. 이를 요약하면 다음과 같다. 1. 단일 population에 있어서 t 시기(년 또는 어기)와 t+1 시기와의 초기자원량(미수)의 관계는 $N_{0,\;t+1}=N_{0,\;t}(1-m_t)-C_t+R_{t+1}$ 단, $N_0$ : 초기자원량 (미수), C : 어획미수, R : 가입미수, m : 자연사망률 이다. 위의 식에서 다음의 관계가 성립된다. $\phi_{t+1}=\frac{(1-\varrho^{-z}{t+1})Z_t}{(1-\varrho^{-z}t)Z_{t+1}}-\frac{1-\varrho^{-z}t+1}{Z_{t+1}}\phi_t-a'\frac{1-\varrho^{-z}t+1}{Z_{t+1}}C_t+a'\frac{1-\varrho^{-z}t+1}{Z_{t+1}}R_{t+1}$ 단, $\phi$ : 밀도지수, M : 자연사망계수, Z : 감소계수, a' : 평균자원량에 대한 밀도지수 이 식에서 $\phi$ 및 $C_t$를 독립변수, $\phi_{t+1}$를 종속변수라해서 중회귀분석하여 $\phi_t$ 및 $C_t$ 의 각 계수를 구하고, 이 각 계수로서 저연사망계수 M, 단위노력당 어획계수 a'을 구하여 t+1연의 가입량추정치 $\hat{R}_{t+1}$를 구할 수 있다. 중회귀분석하는 데 있어서는 $R_{t+1}$이 거의, 같으며 $X_{t+1}$에 심한 차이가 없는 시기를 선정하여 취급할 수 있다. 2. 각 시기의 추정된 가입량은 가입량의 상대치로서 인정하는 것이 안전하다. 3. 밀도지수 대신으로 자원량지수를 사용하여도 같은 추정방법으로 가입량이 추정된다. 단, 어장면적을 고려해야 한다. 4. 변동관계를 미수로서 취급할 때는 이론적으로 가입량의 절대치를 구할 수 있으나, 중량으로 취급할 때는 이론적으로 가입량의 상대치를 구하게 된다. 그러나 어느 경우나 같은 추정방법이 적용된다. 5. 인도양의 bigeye tuna에 대하여 수전(1970)의 자료를 이용하여 본 추정방법에 적용시켜 보았다. 수전(1970)가 구한 M,q(단위노력당 어획계수)로서 계산된 각년의 가입량의 변화와 본연구에서 구한 각년의 가입량의 변화와는 극히 비례적이었다(Table 2, Fig.2). 6. 한국동안의 꽁치에 있어서 해황어황 주간예보 ($1964.3\~1974.8$ : 국립수산진흥원 포항지원)의 자료를 이용하여 어느 해의 춘하기의 밀도지수와 그해의 추동기의 밀도지수와의 관계에서 각년의 추기의 가입량을 추정하고 어느 해의 추동기의 밀도지수와 다음해의 춘하기의 밀도지수와의 관계에서 각년의 춘하기의 가입량을 추정하였다(Table4, Fig.5, Fig.7). 그 결과, 년금의 폭이 좁은 이 꽁치 군단에 있어서 각년의 밀도지수와 가입량이 상당히 비례적이었다.

• 대한전기학회:학술대회논문집
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• 대한전기학회 1995년도 하계학술대회 논문집 C
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• pp.1081-1084
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• 1995

Internal voids located within an insulation will arise partial discharge that causes local breakdown and even the entire insulation breakdown. For HV apparatuses, it is usual case that several voids are formed within non-uniform electric field condition rather than single void within uniform field, which can be solved analitically. The purpose of this work is to study partial discharge and breakdown characteristics of an insulation according to the distribution pattern of two disc-type voids that are located within non-uniform field. The results from numerical field analysis and experiments show that the electric field within the voids decreases as they are arranged more serially, which accordingly results in the increase of partial discharge inception field(PDIF) much higher than that of single void model. With parallel arranged voids, PDIF is almost the same as that of single void model. On the other hand, AC breakdown strength decreases as voids are arranged more serially, which is a natural result considering the reduction of effective insulation thickness. For parallel voids, this effect cannot he noticed where as they show different pattern compared with single void and serial void models in $\Phi$-Q-N analysis. Considering these results may leads us to the conclusion that, in the evaluation of insulating products through PD test, it is not sufficient to determine only PDIV or existence of PD at predetermined voltage level. We could evaluate more accurately by considering all the available data such as PDIV, PD magnitude, PD occurring phase, number of PD pulses, and etc.

• 대한전기학회논문지:전기물성ㆍ응용부문C
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• 제51권5호
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• pp.213-221
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• 2002

In order to improve the reliability of XLPE cables, it is necessary to find the useful diagnostic parameter according to long term aging. This paper described the change of partial discharge(PD) phase Properties of XLPE cable insulation with branch type electrical tree degradation. for long term aging. To understand the PD Properties with $\phi$ -q-n distributed shape of XLPE insulation, specimens were prepared by 22.9㎸ distribution cable and made in a type of block(16${\times}$16${\times}$3[mm]). Ogura needles having tip radius of l0${\mu}{\textrm}{m}$ were inserted into each block pieces. The measuring system was consisted of PD detector, digitizer for digital conversion, VXI system for signal processing. The PD properties of the specimens were measured from initiation of tree to breakdown and their characteristics were analyzed. We analyzed the relationship between electrical properties(PD Quantity, PD initiation angle, PD extinction angle, PD occurrence angle : (PD extinction angle - PD initiation angle)) and the normalized aging rate. We found PD parameter, PD initiation angle and occurrence angle, which are a useful diagnostic parameter in estimating the branch type electrical tree for XLPE insulation condition.

• Journal of Photoscience
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• 제8권3_4호
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• pp.105-112
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• 2001

Susceptibility to low temperature photoinhibition in photosynthetic apparatus was compared among three cucumber cultivars, Gahachungjang (GH), Banbaekjijeo (BB) and Gaeryangsymji (GR). By chilling in the light for 6 h, a sustained decrease in the potential quantum yield (Fv/Fm) and the oxidizable P700 contents was observed, and the decrease was less in GH than in BB and GR. Although the difference was small, some $\Phi_{PSII}$ remained in GH after light-chilling for 6 h indicating that a few electrons can flow around photosystem II(PSII). As a consequence, the primary electron acceptor of PSII, $Q_{A}$, was reduced slowly and was not fully reduced after light-chilling for 6 h in GH. Although the amplitude was small, the development of NPQ was also faster in GH, indicating a higher capacity for non-photochemical energy dissipation. The relative fraction of a fast relaxing component of NPQ (qf) was higher in GH. After light-chilling for 5 h, the values of qf in BB and GR became much smaller than that in GH, indicating BB and GR suffered more significant uncoupling of ATPase and/or irreversible damages in PSII. When fluorescence induction transients were recorded after chilling, significant differences in quenching coefficients (qQ and qN) were observed among the three cultivars.

• 대한수학회보
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• 제55권2호
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• pp.533-543
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• 2018

Under the symbol ${\Omega}$ is a combination of ${\phi}_i$ ($i=1,2,3,{\ldots},n$) which has a suitable growth condition, for dimension n = 2 and $n{\geq}3$, when the initial data f belongs to homogeneous Sobolev space, we obtain the global $L^q$ estimate for maximal operators generated by operators family $\{S_{t,{\Omega}}\}_{t{\in}{\mathbb{R}}}$ associated with solution to dispersive equations, which extend some results in [27].

• KIEE International Transactions on Electrophysics and Applications
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• 제11C권2호
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• pp.12-17
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• 2001

In this work, the correlation between the PD Patterns and the electrical tree propagation has been investigated by use of the specimen removed from the insulation of the real 154 kV XLPE underground power cables. As a result, it could be deduced that the PD pattern regarding electrical trees depends on their type which could be classified into three different distinct groups such as branch-bush mixed. Considering the results of our investigation, if the partial discharge magnitude is only considered for the diagnosis of the cable system, it is possible to draw a wrong decision. Therefore, it is possible to propose that the time characteristics of PD pattern should be taken into account for the diagnosis of the cable system in addition to the conventional $\Phi$-q-n characteristics.

• Nuclear Engineering and Technology
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• 제3권3호
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• pp.148-154
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• 1971

원자로를 여러가지 불연속적 방법으로 가동시킬 때 얻어지는 방사성동위원소의 생성량을 구하는 식을 안출하였다. 특히 현재 우리나라 원자로의 가동조건인 월요일부터 목요일까지 매일 평균 8.2시간을 가동하고 금요일과 일요일은 가동치 않고 토요일은 평균 3.2시간으로 가동하는 조건을 중점적으로 다루었다. 이 경우의 activity를 구하는 식은 생성동위원소가 제 2의 핵반응으로 소실되지 않을 경우에는 (equation omitted) 가 된다. 여기서 A: activity (dps), $\Phi$: 중성자속(n $cm^{-2}$ sec$^{-1}$), No: 조사되기전 원자수, $\sigma$: 방사화단면적($\textrm{cm}^2$), λ: 생성방사성동위원소의 붕괴상수($hr^{-1}$), t： 조사하기 시작해서 끄집어낼 때까지의 시간(hr), n: 조사일수, m:금요일이 처음 나타날 때까지의 조사일 수, s, r, q: 조사기간중 금요일, 토요일 및 일요일이 나타난수를 각각 뜻한다. 윗식은 거의 고정항들로 구성되 있으므로 각 동위원소에 대해 이 고정항들을 계산하여 그 값을 구해 도표를 만들어 이 식이 보다 편리하게 이용되도록 하였다.

• The Korean Journal of Ecology
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• 제14권1호
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• pp.25-38
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• 1991

Berchemia berchemiaefolia is a native a native rare plant which has been designating as the Natural Monument, No. 266, since 1980. The floristic composition, population structure and maintenance mechanism of the Berchemia berchemiaefolia forest were investigated in conjunction with the habitat consisted of the block field or screes. Through the present study, the authors found a new habitat of Berchemia berchemiaefolia in the northeastern slope on Mt. Kumdansan located at Hajeok-ri, Cheongcheon-myeon, Koesan-gun, chungbuk province. Gravels consisted of the block field belonged to granule, pebble and cobble as the range of grain size, $\Phi$=-1.5~6.6 values. The tree layer of Berchemia berchemiaefolia community was mainly composed of Quercus variabilis, Pinus densiflora and Q. serrata including Berchemia berchemiaefolia and of this community were similar to that of Q. variabilis. By the age distribution, it was considered that the community was a discontinued one as the pattern of distribution was a normal distribution type(N type). Phenological cycle including leafing, blooming and seed-bearing period between both sites of block field and valley or close canopy showed some differences. The seed production of Berchemia berchemiaefolia was 8, 655, 000 seeds/ha/year, but only 406, 000 seeds/ha/year of them were developed as saplings, and only 4 saplings were developed to mature trees.

• 한국전기전자재료학회:학술대회논문집
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• 한국전기전자재료학회 2003년도 제5회 학술대회 논문집 일렉트렛트 및 응용기술연구회
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• pp.29-32
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• 2003

Recently, the development of diagnosis technique with high confidence is important on power equipment, for this reason is to use for measurement and analysis of PD with prior appearance of insulation breakdown In this paper, we presents the analysis of trouble signal to use both method of general analysis of $\Phi$-Q-N in PD and statistical parameter by this interpretation Equipment of simulation has made independently DS for 170kV GIS of one phase with same on field. The detected signal through the sensor of Induction and Acoustic Emission is classified which used to characteristic neural network algorithm and then it is analysis.

• 한국전기전자재료학회:학술대회논문집
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• 한국전기전자재료학회 2001년도 하계학술대회 논문집
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• pp.481-484
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• 2001

High voltage induction motors are widely used in industrial factory because have many benefits. But the insulated materials of induction motor are aged by using time, electrical, thermal, circumstantial stresses and so on. Motor failures are occurred by these deterioration phenomena and give rise economic problems to user. In many motor failures, insulated material problems of stator winding happen frequently and occupy high percentages in the failure source. In this paper, the testing specimen(motorette) is manufactured by modeling of stator winding of high voltage induction motor and accelerating test is carried out. Partial discharge signals detected by RF sensor are used to analyze deterioration condition of stator windings. According to aging time, the 3D ( ${\Phi}$-Q-N) distribution and skewness of partial discharge signals are changed.