• Korean Journal of Weed Science
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• v.16 no.2
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• pp.108-113
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• 1996

The experiment was conducted to obtain basic information on occurrence ecology system of Aneilema japonica and to establish its effective control systems in dry seeded rice at National Yeongnam Agricultural Experiment Station in 1995. Total amount of weed in dry seeded rice in the following year('95) as affected by control of barnyardgrass at 70 days after seeding(DAS) in previous year('94) was reduced 47.7% at 30 DAS and 7.8% at 60DAS and also exhibited different weed occurrence as compared with no control plot. Especially in control plot at 60 DAS, occurrence of Echinochloa crus-galli was reduced by 46.9%, But the growth of Aneilema japonica which is one of the problems in weed species was drastically increased by 231 % and Persicaria hydropiper by 11.8%, respectively. Suppressed tillering of rice plant as affected by occurring of A. japonica(300-750 plants/$m^2$) occurred from about 40 DAS and rice grain reduced 74-93% compared with hand weeding due to reduced panicle number. Soil applied Butachlor(EC) at 5 DAS, foliar applied Propanil -Butachlor(EC) at 13 DAS and Lgc 40863+Pendimethalin at 20 DAS were very effective for Aneilema japonica. As considering both weed suppression of Aneilema japonica and yield capacity, middle late foliar application of Lgc 40863+Pendimethalin and systematic application of Butachlor at 5 DAS followed by Propanil/Molinate at 25 DAS were the most effective control systems.

• Journal of the Korean Institute of Illuminating and Electrical Installation Engineers
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• v.18 no.2
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• pp.68-74
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• 2004

This paper presents a novel hybrid multilevel inverter using DC-Link voltage combination in order to improve the waveshape of output voltage and reduce harmonics. The proposed multilevel inverter can generate an 11-level output voltage. It employs three H-bridge cell, which consists of single phase full-bridge inverter module. Among them, two modules are used for level generation, and one module performs PWM switching. Nine levels are synthesised by the level inverter, and two levels are added to output by the PWM inverter. As a result, it generates an 11-level. The operational principles are explained in depth, and the validity of the proposed system is verified through the PSpice simulation and experimental results based on a prototype.

• The Transactions of the Korean Institute of Power Electronics
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• v.7 no.2
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• pp.165-170
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• 2002

In order to solve the problem of system efficiency reduced on account of two stage power conversion, we propose a series resonant full bridge Inverter circuit for battery-fed microwave oven. This circuit has both a compact size and a light weight comparing with the conventional HVT(High Voltage Transformer) method. Also, it may be adjusted power levels of the microwave oven by a frequency control. In this paper, operational principles are explained in detail in order to understand the circuit operation. Also, a proto-type Inverter circuit with 1[kW] Power consumption is built and tested for verifying the operation.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.7 no.2
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• pp.157-162
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• 2006

In this paper, power supply for ozone generating system is explained. Output voltage and frequency are controlled by phase displacement control of single phase inverter using ATmega128. The values of desired output voltage and frequency set using keypad and displayed using LCD. Actually, power supply is designed and manufactured. Through the experiments, the performance of output voltage and frequency control is verified.

• Proceedings of the KIPE Conference
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• 2012.07a
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• pp.397-398
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• 2012

현재 단상 태양광 인버터 분야에서는 고효율을 달성하는 것과 태양전지의 기생 커패시터에 의해 발생하는 지전류를 저감하는 기술이 큰 이슈가 되고 있다. 대중에게 알려진 단상 태양광 인버터 토폴로지로는 풀브릿지, H5, H6, HERIC (high efficiency and reliable inverter concept)등이 있다. 본 논문에서는 풀 브릿지 회로의 바이폴라, 유니폴라 및 하이브리드 변조방식과 H5, H6, HERIC 회로에 대해서 시뮬레이션과 시제품 제작을 통하여 작동원리를 파악하고, 효율과 지전류를 비교하도록 하겠다.

• Journal of IKEEE
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• v.26 no.4
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• pp.584-589
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• 2022

For DC-AC power conversion from a high-voltage photovoltaic panel to a single-phase grid, the two-stage transformerless inverter with a buck-boost converter followed by a full-bridge inverter is widely used. To avoid an excessive leakage current due to the large parasitic capacitance of the photovoltaic panel, the full-bridge inverter can only adopt the bipolar PWM which results in much higher power loss compared to the unipolar PWM. In order to overcome such a poor efficiency, this paper proposes a new topology in which an IGBT and a diode for circuit isolation are added to the buck-boost converter. The proposed circuit isolation method allows the unipolar PWM in the full-bridge inverter without any increase in the leakage current so that the overall efficiency can be improved. The validity of the proposed solution is verified by computer simulation and power loss calculation.

• 한국해양학회지
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• v.25 no.3
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• pp.145-150
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• 1990

An analysis of collected data on components of dissolved organic phosphorus (DOP) and DOP is made to search for important components of DOP pool and their implications in phosphorus (P) cycling. The significance of dissolved nucleic acids (D-NA) apparently tends to increase with increasing trophic status of oceanic waters. Interestingly the sum of all 5-nucleotide and D-NA seems to dominate the DOP pool. Thus, materialization of D-NA could be a significant pathway of P cycling in surface oceanic waters and it might be of great importance in lakes where P limits primary production. Processes related to death of Microbes are responsible for D-NA and DOP production in surface waters, and incomplete digestion of preys by grazers seems to be an important mechanism in D-NA production.

• Journal of the Korean Institute of Illuminating and Electrical Installation Engineers
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• v.19 no.8
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• pp.56-61
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• 2005

The induction heating is widely used not only in the industrial fields but also in the home appliances. But the conventional induction heating systems have shortcoming that it use only magnetic utensil, in this paper, heating of Aluminum sheet by full-bridge series resonant high-frequency inverter is proposed. Also, the principle of induction heating and operations of full-bridge inverter equivalent circuit are explained. The proposed inverter controls the output voltage using phase-shift irrespective of the switching frequency using phase-shift. As a result the proposed induction heating system by full-bridge resonant inverter shows the possibility that make up for the shortcoming of the conventional existing induction heating systems.

• 한국생태학회:학술대회논문집
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• 1998.05a
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• pp.106-106
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• 1998

• Korean journal of food and cookery science
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• v.14 no.2
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• pp.201-206
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• 1998

This study was conducted to determine the changes in the contents of vitamin C and reducing sugars of wheat flour and glutinous rice pastes added Kimchi during fermentation. Kimchi was fermented at 10$^{\circ}C$ for 14 days. Sensory evaluation of various Kimchi samples were also conducted. During fermentation, pH decreased in the order of wheat flour paste added Kimchi (WHFP-Kimchi), glutinous rice paste added Kimchi (GLRP-Kimchi) and control. Total acidity increased in the same order The contents of total vitamin C of all Kimchi samples decreased. Total reducing sugar contents of Kimchi juices from various samples decreased in the order of WHFP-Kimchi, GLRP-Kimchi and control. In sensory evaluation, the red color of Kimchi juice decreased in the order of control>WHFP-Kimchi>GLRP-Kimchi. Off flavor decreased control>WHFP-Kimchi>GLRP-Kimchi. Firmness decreased control> GLRP-Kimchi>WHFP-Kimchi. Sour tate decreased WHFP-Kimchi>Control>GLRP-Kimchi. But there were no significant difference in crispiness, ans salty taste. Overall prefernce decreased GLRP-Kimchi>control>WHFP-Kimchi.