• Korean Journal of Hydrosciences
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• v.3
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• pp.81-96
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• 1992

This study represents the methodology for feasibility analysis of small hydro power SHP plant. Cumulative density function of Weibull distribution and Thiessen method were adopted to decide flow duration curve at SHP candidate site. The perfomance prediction model and construction cost estimation model for tunnel-type SHP plant were developed. Eight tunnel -type SHP candidate sites existing on Han-river were selected and surveyed for actual site reconnaissance. The performance characteristics and economical feasibility for these sites were analyzed by using developed models. As a result, it was found that the optimum design flowrate with the lowest unit generation cost for tunel-type SHP candidate site were the flowrate concerming with between 20% and 30% of time ratio on the flow duration curve. Additionally, primary design specifications such as design flowrate, effective head, capacity, annual averageload factor, annual electricity production were estimated and discussed for eight surveyed SHP candidate sites.

• Proceedings of the Korean Society of Machine Tool Engineers Conference
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• 2003.04a
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• pp.73-78
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• 2003

Ultrasonic measurement is one of important technologies in the lift-time maintenance of nuclear poler plant. Ultrasonic inspection system is consisted of the operator, equipment and procedure. The reliability of ultrasonic inspection system is affected by its ability. The performance demonstration round robin was conducted to quantify the capability of ultrasonic inspection for in-service. The small number of teams who employed procedures that met or exceeded ASME Sec. XI Code requirements detected the piping of nuclear power plant with various cracks to evaluate the capability of detection and sizing. In this paper, the statistical reliability assessment of ultrasonic nondestructive inspection data using Monte Carlo simulation is presented. The results of the probability of detection (POD) analysis using Monte Carlo simulation are compared to these of logistic probability model. In these results, Monte Carlo simulation was found to be very useful to the reliability assessment f3r the small hit/miss data sets.

• Korean Journal Plant Pathology
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• v.14 no.6
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• pp.732-734
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• 1998

Leaf spot of Amelanchier asiatica was observed in Korea.. The major symptoms of the disease were small necrotic spots and severe early defoliation. On the basis of morphological characteristics of the fungus observed from naturally infected leaves, the causal organism was identified as Entomosporium mespili (DC. : Duby) Sacc. The conidial suspension prepared from sporulating lesions was sprayed on healthy leaves with or without wounding to prove pathogenicity of the fungus. Small spots were noticed tow days after inoculation, and acervuli containing numerous conidia were observed 7 and 10 days after inoculation from wounded and unwounded leaves, respectively. This is the first record of the disease on A. asiatica in Korea.

• Solar Energy
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• v.18 no.3
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• pp.153-160
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• 1998

The methodology and feasibility analysis model for small hydropower plant has been studied and developed. It consists of two main part, the performance prediction model to estimate the performance characteristics and economics anaysis model to evaluate economical characteristics for surveyed sites. The performance characteristics and feasibility assessment for surveyed sites were analyzed, using developed models. Also, primary design specifications such as design flowrate, capacity, load factor were estimated and discussed for surveyed sites in Dan-yang and feasibility was suggested through analyzing the investment, unit cost and payback period.

• The Transactions of the Korean Institute of Electrical Engineers
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• v.41 no.8
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• pp.841-849
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• 1992

In power system operation, the stability of synchronous machine has been recognized one of the most important things. AESOPS program developed by EPRI in U.S.A. is a frequency domain analysis program in power system stability and it computes the electro-mechanical oscillation mode. This paper presents how to analyze the power system small signal stability problem efficiently by uusing the AESOPS program and analyze the various factors affecting the damping characteristics of these oscillations in KEPCO power system of 1986 with pumped-storage plant. To reduce the computing time and efforts, selecting the poorly-damped oscillation mode and clustering technique have been used. The characteristics of load, the amount of power flow on the transmission line and the gain of exciter have a significant effects on the damping of the system while the governing system has only a minor one. With the Power System Stabilizers, the stability of the power system has been improved.

• Korean Journal of Plant Resources
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• v.4 no.1
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• pp.5-12
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• 1991

A combination of acerocarininc-Wright C-banding technique was utilized to identify each chromosomes in durum wheat ,Triticum durum var. Hordeiforme (2n=4x=28 AABB), This technique elucidated qualitativr and quantitative traits of the indi-vidual chromosomes In coinplement. Most comspicuous bands were observed at thecentromere of B-genome chronmosomes. Each chromosomes of A-genome had some-what weak centromeric, proximal and terminal bands. Chromosomes 2A and 4A hasa small subterminal bands. 6A is smallest and metacentric chromosome and , has two faint interstitial band. Chromosomes 1B and 6B showed satellite and constriction lage band. Short arm of 3B has three heavily interstitial bands. Both arms of chromosome 4B has a lagc centromeric band and a very lage proximal band. 5B had heavilycentromeric band and the long arm showed prominent two interstitial bands. Chromo-somes 25 and 7B has a small terminal band of both arms.

• Research in Plant Disease
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• v.28 no.2
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• pp.108-111
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• 2022

In December 2020, stem and leaf rot symptoms in small-fruited tomato (Solanum lycopersicum) plants were observed in a farmer's vinyl greenhouse located in Pyeongtaek, Gyeonggi Province, Korea. The incidence of diseased plants in the vinyl greenhouse was 2-6%. Seven single-spore isolates of Phoma sp. were obtained from the diseased stems and leaves. All the isolates were identified as Boeremia linicola based on the cultural, morphological and molecular characteristics. Two isolates of B. linicola were tested for pathogenicity on stems and leaves of small-fruited tomato and large-fruited tomato using artificial inoculation. All the tested isolates caused stem and leaf rot symptoms in the inoculated plants. The symptoms were similar to those observed in plants from the vinyl greenhouse investigated. This is the first report of B. linicola causing stem and leaf rot in tomato.

• Journal of Life Science
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• v.16 no.2 s.75
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• pp.240-244
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• 2006

We present a fast and simple protocol for purification of mitochondria, mitochondrial DNA, and RNA from small amounts of tomato leaves. This method uses a high ionic strength medium to isolate mitochondria and extract mitochondrial DNA and RNA from a single preparation and is easily adaptable to other plant species. Mitochondria was confirmed by MitoTracker. The mitochondrial DNA was not contaminated by plastid DNA, was successfully used for PCR. Similarly, the isolated mitochondrial RNA was not contaminated only slightly contaminated (leaves) by plastid RNA. RNA prepared according to our method was acceptable for RT-PCR analysis

• The Transactions of The Korean Institute of Electrical Engineers
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• v.60 no.6
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• pp.1128-1133
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• 2011

In a wind farm, a large number of small wind turbine generators (WTGs) operate whilst a small number of a large generator do in a conventional power plant. To maintain high quality and reliability of electrical energy, a wind farm should have equal performance to a thermal power plant in the transient state as well as in the steady state. The wind farm shows similar performance to the conventional power plant in the steady state due to the advanced control technologies. However, it shows quite different characteristics during fault conditions in a grid, which gives significant effects on the operation of a wind farm and the power system stability. This paper presents an analysis of response of a wind farm during grid fault conditions. During fault conditions, each WTG might produce different frequency components in the voltage. The different frequency components result in the non-fundamental frequencies in the voltage and the current of a wind farm, which is called by "beats". This phenomenon requires considerable changes of control technologies of a WTG to improve the characteristics in the transient state such as a fault ride-through requirement of a wind farm. Moreover, it may cause difficulties in protection relays of a wind farm. This paper analyzes the response of a wind farm for various fault conditions using a PSCAD/EMTDC simulator.

• Plant Disease and Agriculture
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• v.5 no.1
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• pp.34-40
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• 1999

The virus infection rates and disease symptoms of three major citrus viruses, citrus tristeza virus (CTV), satsuma dwarf virus (SDV), and citrus tatter leaf virus (CTLV), were investigated at 35 citrus orchards in Cheju Island from 1995. The infection rates of CTV, SDV, and CTLV were 69.8%, 8.6%, and 9.3%, respectively. However, depending on cultivars there were significant differences in the infection rates. The infection rates of CTV were highest in early satsuma mandarin (Citrusunshiu) with 80.9% and lowest in very early satsuma mandarin with 51.9%. In SDV, the highest was in very early stasuma mandarin with 23.1% and the lowest was in early satsuma mandarin with 6.3%. And the highest infection rate in very early satsuma mandarin with 17.9% and the lowest in tangors with 7.3% in CTLV. The symptoms of virus-infected citrus were very diverse; small and abnormal shape of fruits, abnormal leaves such as narrow boat and small spoon shapes of leaves, stem-pitting on the twig, bud-union crease and swelling of the graft part, reduction of the plant vigor and poor yields.