• Transactions of the Korean hydrogen and new energy society
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• 제17권3호
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• pp.286-292
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• 2006

Chlamydomonas reinhardtii is a green algae that can use light energy and water to produce hydrogen under anaerobic condition. This work reports the effect of limiting factors on hydrogen production in sulfur deprived anaerobic C. reinhardtii culture. In order to confirm the relationship between hydrogen production and limiting factors such as residual PSII activity and endogenic substrate degradation, the increase in chlorophyll concentration and the decrease in starch concentration was investigated during sulfur deprivation. The overall hydrogen production increased depending on cell density in range of $0.4{\sim}0.96\;g$ DCW/l. At this time, the increase in chlorophyll concentration during 24 h after sulfur deprivation increased in proportion to hydrogen production, however, the decrease in starch concentration was not proportional to that. Therefore, hydrogen production under sulfur deprivation using green alga was closely associated with the residual PSII activity than the endogenic substrate degradation.

• Journal of the Korean Society of Environmental Restoration Technology
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• 제27권4호
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• pp.29-43
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• 2024

The purpose of this study was to analyze the soil on two waste areas that lack plants to find out the limiting factors of plant introduction, and to find out the possibility of plant introduction through plant growth experiments by mixing the two waste soil. In the case of tungsten waste soil, insufficient organic matter, water content, effective phosphoric acid, and nitrogen content were the limiting factors for plant introduction, and in the case of coal waste soil, low pH of the soil acted as the limiting factors for natural introduction. Growth experiments showed that the number of leaves of Ipomoea nil grown in soil mixed with both waste soil was 2.7 times greater than that of Ipomoea nil grown in tungsten waste soil, and 2.29 times greater than that of Ipomoea nil grown in coal waste soil. The fresh weight comparison showed that Ipomoea nil grown in soil mixed with the two waste soil had a fresh weight of 2.64 times higher than that of tungsten waste soil and 2.45 times higher than that of coal waste soil. There was no significant difference in the fresh weight of Ipomoea nil grown in soil mixed with the two waste soil and in general soil. Therefore, when the two waste soil are mixed, it can be judged that the components unfavorable to growth complement each other, improving the soil and being effective in plant growth.

• Asian-Australasian Journal of Animal Sciences
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• 제6권3호
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• pp.347-360
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• 1993

The project was undertaken to provide information on the present system of traditional pig farming in the South Pacific region, to identify the problems currently limiting productivity of such pigs and to offer practical strategies which could be used for increasing productivity of the animals. The problems were identified by surveying some 220 subsistence pig farms in eleven island countries in the South Pacific region using a prepared questionnaire. The units were found to be generally small, consisting of about 2-4 sows per herd. The productivity of the units as assessed in terms of sow reproductive efficiency was rather low, being only about 7.5. Feed, housing, breeding, disease, marketing, lack of capital, technical know-how and existing social traditions were identified as current constraints. Based on three of the most limiting factors identified namely feed, housing and breeding, strategies for improvement were developed on the basis of better and more effective use of locally available feed resources, better housing and genetic improvement through crossbreeding programmes. These improvement strategies were tested as a package model on some ten farms in two of the island countries. The results of these on-farm trials indicated that using the improvement strategies increased sow reproductive efficiency by approximately 60 percent, to nearly 12. The significance of these findings in the overall management of traditionally raised pigs in the South Pacific region is discussed.

• Korean Journal of Air-Conditioning and Refrigeration Engineering
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• 제16권11호
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• pp.1013-1020
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• 2004

The hybrid system of gas turbine and fuel cell is expected to produce electricity more efficiently than conventional methods, especially in small power applications such as distributed generation. The solid oxide fuel cell (SOFC) is currently the most promising fuel cell for the hybrid system. To realize the conceptual advantages resulting from the hybridization of gas turbine and fuel cell, optimized construction of the whole system must be the most important. In this study, parametric design analyses for pressurized GT/SOFC systems have been peformed considering probable practical limiting design factors such as turbine inlet temperature, fuel cell operating temperature, temperature rise in the fuel cell and soon. Analyzed systems include various configurations depending on fuel reforming type and fuel supply method.

• 제어로봇시스템학회:학술대회논문집
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• 제어로봇시스템학회 1996년도 한국자동제어학술회의논문집(국내학술편); 포항공과대학교, 포항; 24-26 Oct. 1996
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• pp.577-580
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• 1996

LQ-servo is a stability-robustness guaranteed multivariable controller design method based on the LQR structure to improve command following performance with output feedback. In this paper, a new type of PI controller based on LQ-servo is introduced. Then, Command following performance is improved using the limiting behavior of the control gain and weighting factors on the low frequency part of design parameter Q that is the state weighting matrix in the cost function.

• 전기의세계
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• 제14권5호
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• pp.8-14
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• 1965

Because of the flat slope of the magnetic characteristic curves at high saturation, the transformer inrush current peakes may assume an extreme magnitude. Even though such is rarely any danger to the transformer itself, the currents can cause serious problems in associated apparatus. This paper has analyzed various limiting factors of excess inrush currents, and then has suggested how to determine the frequency of encountering the inrush current peaks higher than an arbitrarily chosen value by deriving the probability equations of inrush current occurrence.

• The Korean Journal of Ecology
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• 제8권2호
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• pp.89-98
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• 1985

Correlations between horizontal distributions of bamboos (Bambusaceae) in the Korean peninsula and environmental factors were studied using taxanomic and geographical literatures, both old and current. The vertical distributions of bamboos on Mt. Chiri were also studied, and environmental factors limiting horizontal and vertical distributions were compared. There are 18 species of bamboos (belonging to 5 genera) distributed in the Korean peninsula. The distributional range of each genus were distinct, although overlapped. Northern limit of bamboos of any species was marked by the line connecting Paikryung Island (124。40'E, 38。00'N), Mt. Changsoo, Mt. Myungji, Mt. Myohyung and Myungchum (129。40'E, 41。10'N). The optimum range of bamboos was concluded to be restricted to several southern province, with annual precipitation over 1,200 mm. The limiting factors on the distribution were inferred to be low temperature and duration of it. Mean daily minimum temperature of January and the number of days with daily mean temperatures below zero during January showed close associations with the distributional range, and an environmental factors favouring the distributrion of bamboos appeared to be vicinity of warm sea current, deep and extended snow acculation and southern exposure. The vertical distribution of bamboos on Mt. Chiri was limited by low temperature, unfavorable topographic and edaphic conditions caused by steep slope. Difference in the vertical limits between SE and NW slopes are caused by the differences in temperature and precipitation between the slopes. Bamboos were more abundant in valleys than on the ridge, apparently because the deeper snow in the valleys protected the plants from low temperature, heavy winter winds and desiccation.

• Proceedings of the Korean Society for Agricultural Machinery Conference
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• 한국농업기계학회 2000년도 하계 학술대회 논문집
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• pp.281-286
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• 2000

• Proceedings of the SAREK Conference
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• 대한설비공학회 2004년도 하계학술발표 논문집
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• pp.177-177
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• 2004

• 한국정보디스플레이학회:학술대회논문집
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• 한국정보디스플레이학회 2009년도 9th International Meeting on Information Display
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• pp.1129-1129
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• 2009

Here the improved performance of polymer/polymer solar cells, which are of importance to achieve real plastic solar cells in the near future, is reported. First, the progress in polymer/polymer solar cells is briefly reviewed and then the limiting factors are discussed in terms of charge transport.