• Journal of Biosystems Engineering
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• v.14 no.1
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• pp.1-7
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• 1989

This study was carried out to develop a system and methodology to simulate the engine load variation occuring during agricultural field operations for a laboratory engine test. The system consisted of an electric dynamometer, an Apple II microcomputer, and a data acquisition and control system. Several pieces of instruments were utilized to measure various engine performance data. Both engine torque and engine speed were fully controlled by a computer program. The dynamic characteristics of the system were analyzed through a series of tests and the limitations on the load simulation test were presented. The results of the study are summarized as follows: 1. Engine speed and toque were controlled by a computer program. The use of a stepping motor and reduction gears enabled engine speed be controlled within 1 rpm. 2. The natural frequency of the dynamometer-engine system was found to be around 5 Hz, at which the load simulation would be impossible because of resonance. 3. For the harmonic inputs with the frequencies above the natural frequency, the signal attenuated too much and therefore the load simulation was impossible. 4. The step response of the system showed an overshoot of 24.5 percent and the settling time for 5 percent criterion was around 3 seconds. 5. When actual field test data are utilized for load simulation, a low-pass filter should be included to attenuate the frequency components around and above the natural frequency.

• Transactions of the Korean Society of Automotive Engineers
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• v.19 no.2
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• pp.142-147
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• 2011

Compressed natural gas (CNG) is well known as one of the cleanest burning alternative fuels. Bi-fuel CNG vehicle can also run on gasoline or another fuel while dedicated natural gas vehicle is designed to run on natural gas only. Recently, increased attention has been focused on bi-fuel CNG/LPG taxi because of good fuel economy of CNG. A number of LPG taxis modified to CNG Bi-fuel vehicles are running in many cities. In this paper, the emissions characteristics of in-use passenger cars running on CNG and LPG were investigated. Chassis dynamometer test was used to measure exhaust emissions from an in-use fleet of 5 cars. Exhaust emissions were collected for CVS-75 driving mode. The test results showed that for CNG fuel mode, CO, $CO_2$ and NMHC emissions decreased to 9%, 12% and 14% respectively, and $CH_4$ and $NO_x$ emissions increased to 317% and 47% respectively.

• Journal of the Korean Solar Energy Society
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• v.24 no.2
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• pp.25-31
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• 2004

Ventilation through air vent system in a building envelope is expected to be an effective measure to release solar radiation. An external surface of a wall absorbs solar radiation and transfers it to the air in the cavity. The warmed air gets buoyant force. So when openings are provided at the top and bottom of the cavity, the warmed air is released through the top opening and cooler outside air replaces the space in the cavity. This reduces the further heat transmission into the built environment. This natural ventilation effect seems to be steady and strong. So because of the cavity and the openings, the cooling load reduction by natural ventilation is believed to be considerable.

• Corrosion Science and Technology
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• v.6 no.6
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• pp.269-274
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• 2007

The corrosion of steel in concrete is significant in marine environment. Salt damage is one of the most detrimental causes to concrete bridges and port structures. Especially, the splash and tidal zones around water line are comparatively important in terms of safety and life-time point of view. During the last several decades, cathodic protection (cp) has been commonly accepted as an effective technique for corrosion control in concrete structures. Zn-mesh sacrificial anode has been recently developed and started to apply to the bridge column cp in marine condition. The detailed parameters regarding Zn-mesh cp technique, however, have not well understood so far. This study is to investigate how much Zn-mesh cp influences along the concrete column at elevated temperature. About 100 cm column specimens with eight of 10 cm segment rebars have been used to measure the variation of cp potential with the distance from Zn-mesh anode at both $10^{\circ}C$ and $40^{\circ}C$ in natural seawater. The cp potential change and current diminishment along the column specimens have been discussed for the optimum design of cp by Zn-mesh sacrificial anode.

• Journal of the Economic Geographical Society of Korea
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• v.5 no.2
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• pp.157-174
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• 2002

This study aims to examine the structure and meaning of the perception of rural amenity which rural and urban residents have. Many Lickert scaled questions measure how much important the respondents think about the various items related to rural amenity respectively. It reveals that there is not meaningful difference in the relative importance among three upper dimensions composing the construct of rural amenity, historic-cultural dimension, natural environmental dimension and living condition dimension. This means that our respondents are not willing to pursue historic-cultural aspects and natural environmental aspects at the risk of living condition being able to enjoy comfortable and affluent opportunities. And also, this results reveals that people might have a quite different perception compared with academic discourse putting much weight on historic-cultural dimension and natural environmental dimension.

• Journal of Power System Engineering
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• v.12 no.5
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• pp.27-33
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• 2008

Natural gas has been considered one of the most promising alternative fuels for transportation because of its abundance as well as its ability to reduce regulated pollutants. We measured emission characteristics of nanoparticles from lean burn H/D(Heavy-Duty) CNG (Compressed Natural Gas) engine equipped with oxidation catalysts. The experiments were carried out to measure the emission and engine performance according to the ESC test cycle. The CO and THC conversion efficiencies on the best catalyst in the ESC test cycle achieved about 91 % and 83 %, respectively. From the measurement by the SMPS, the number of nanoparticles emitted from H/D CNG engine is reduced by about 99 % which is more than that of 2.5 L diesel engine. The particle number concentrations of H/D CNG engine were almost nanoparticles. Nanoparticles smaller than 30 nm emitted from the H/D CNG engine and diesel engine equipped with a CDPF(Catalyzed Diesel Particulate Filter) were quite similar. However, the particles bigger than 30nm from the CNG engine were smaller than the particles from diesel engine equipped with a CDPF. The higher the CNG engine load, the lower the particle number from engine-out, but it increased slightly at full load.

• The Korean Journal of Emergency Medical Services
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• v.5 no.1
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• pp.89-97
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• 2001

Recently, natural disasters happened to the Korea frequently. Disaster in the present society has been changed and increased it impacts and extent of danger as the society develops. So, Korean people feel uneasy about the unpredictable disaster. Therefore the capability of administration system, and cooperation and support between related organization become more necessary. This study aims to find out better ways of disaster management system which can protect people's lives and fortune from all sort of national disasters. To research policy reform, it is necessary to analyze disaster response organization(national disaster prevention countermeasures headquarters and so on), interorganizational relationship, law system etc. Especially, in this study, role appreciation of government was analyzed to get the rational policy reform measure. Suggestion : First, it is necessary Establishing a consolidated organization for disaster managing and united response organization is necessary such as Federal Emergency Management Agency(FEMA) which controls an over all aspects of disaster management. And it is necessary to develop Integrated Administrative Control System based on comprehensive plan. When the accidents happen, it needs to be many equipments and various specialized personnel. So, to manage a large scale of disaster, it is necessary to have interorganizational network system which many specialized organization including volunteer group are integrated. Also, as soon as the natural disaster happen, many professionals and volunteers are distributed to the spots of disaster in the right man in the right place. Finally, All the citizens have to keep safety rules, and also to take a safe action in ordinary daily life.

• ALGAE
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• v.32 no.3
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• pp.189-197
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• 2017

To quantify the abundance of the harmful dinoflagellate Cochlodinium polykrikoides in natural seawaters, we developed the innovative procedure using a droplet digital PCR (ddPCR) with C. polykrikoides-specific primers targeting the internal transcription sequence (ITS). The abundance of C. polykrikoides was estimated by the specific copy number of target ITS DNA segments per cell in cultures and natural water samples. The copy number per C. polykrikoides cell as acquired by ddPCR was $157{\pm}16$, which was evaluated against known cell numbers through a simplified protocol preparing DNAs. The abundances of C. polykrikoides in the waters of different locations estimated by ddPCR agreed with the number of cells visually counted under a microscope. This protocol was used to measure the abundance of C. polykrikoides close to and further off the southern coast of Korea in August of 2016 and 2017. The practical application showed that this method can reduce time for analysis and increase accuracy.

• Korean Journal of Organic Agriculture
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• v.9 no.4
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• pp.71-93
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• 2001

Within the paper, an overview of organic farming in Europe countries is given and the Principle and skills of organic agriculture is shortly reported with special regard to Germany. The overview information on European organic forming is covered such as \circled1 development of organic farming, \circled2organic farming organizations, \circled3standards and certification, \circled4implementation of EU council regulation, \circled5state support, \circled6implementation of Agenda 2000, \circled7training and education, \circled8advisory service and research situation. In the paper the principle and skills for organic farming which are practiced actually in the German organic farms is also reported. How to maintain and increase the fertility and microbiological activity of the soil by \circled1cultivation of legumes, green manures or deep-rooting crops in multi-annual rotation system, \circled2incorporation in the soil organic material, by-products from livestock farming is one of the major principle to organic crop production. Pest and diseases and weeds are controlled by any one, or a combination of the following measure ; \circled1choice of appropriate species and varieties, \circled2appropriate rotation programs, \circled3mechanical cultivation, \circled4protection of natural enemies of pests through provision of favourable habitat and ecological buffer zone, \circled5diversified ecosystems, \circled6flame weeding, \circled7natural enemies, \circled8bio-dynamic preparations, \circled9mulching and mowing, \circled10grazing of animals, ⑪mechanical controls, ⑫steam sterilization.

• Journal of the Korea Furniture Society
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• v.11 no.1
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• pp.53-59
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• 2000

This study was to measure formaldehyde emission and bonding strength of plywoods manufactured with urea-melamine formaldehyde adhesives, which were made from three different mixing ratios of urea and melamine, and with four different formaldehyde/urea-melamine molar ratios of 1.0,1.1,1.2 and 1.4. The results were as follows 1. Amount of formaldehyde emission was the lowest at the first method of molar ratio(F/(M+U)) 1.0. Amounts of formaldehyde emission of experimental manufactured adhesives were lower than that of commercial adhesive. 2. Bonding strength of dry specimen was the highest at the first method of molar ratio(F/(M+U)) 1.4. Dry bonding strength of molar ratio(F/(M+U)) 1.4 was similar to commercial adhesive. 3. Bonding strength of wet specimen was the highest at the second method of molar ratio(F/(M+U)) 1.4. Bonding strength of wet specimen used by the third method of molar ratio(F/(M+U)) 1.4 was almost equal to commercial adhesive.