• Journal of Korean Society of Environmental Engineers
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• v.28 no.10
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• pp.1024-1030
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• 2006

Genus Nitrospira and Nitrobacter species are the key nitrite-oxidizing bacteria(NOB) in nitrifying wastewater treatment plants. It has been hypothesized that genus Nitrospira are K-strategists(low $K_6$ value) that can exploit low amounts of nitrite more efficiently than Nitrobacter. In contrast, Nitrobacter species are r-strategists(high $V_{max}$) that can grow faster than Nitrospira. It has also been known that the availability of organic compounds and dissolved oxygen as well as nitrite affects the distribution of NOB. In this study, we determined the distribution and competition of NOB in wastewater nitrification systems where nitrite, organic compounds, and dissolved oxygen concentrations were compositively varied. For the purpose, several compounds of the laboratory-scale nitrificaiion bioreactor and full-scale $A_2O$ wastewater treatment plant and their distribution of NOB were analyzed and compared. The analysis showed that Nitrobacter was the dominant NOB in nitrification bioreactor where average nitrite was maintained at 5 mg-N/L with very low organic concentration in aerobic condition, whereas Nitrospira was the dominant NOB in full-scale $A_2O$ plant where nitrite was maintained very low and organic compounds were maintained relatively high in alternating aerobic-anoxic condition. The result indicates that nitrite concentration is more critical factor than organics and dissolved oxygen which determines the dominant NOB in nitrification system and it is confirmed that Nitrospira and Nitrobacter showed the characteristics of r-strategist and K-strategist, respectively.

• The Journal of Korean Philosophical History
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• no.31
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• pp.321-346
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• 2011

This is a preliminary study in order to deal intensively with the overall characteristics of Korean military science in the future days. First off, the history of military science of China based on the precedent studies was recapitulated, and a comparative study on the acceptance process of the books on military art and science, as well as on understanding patterns of literati on the subject through literature searches, ranging from the Three Kingdoms Period to the Goryeo Dynasty in Korean peninsula, was conducted. In case of Korea, the Chinese books on military strategy, including Sun Tzu's the Art of War, had already been passed down during the Three Kingdoms Period, and broadly read by scholarly people. They had utilized diverse methods based on their knowledge of Confucianism. In the reference materials, the authors of Korean military strategy books had greatly relied upon the Chinese books on military strategies, however, they had made the military principles run in their own way. At the end of Goryeo Dynasty, 'Military Science' had been well established as a subject in academia, and this curriculum had been taught not only at the National Confucian Academy, Seonggyun-gwan, in the capital but also at the country public school ("Hyanggyo") in the province together with Confucianism. Because of the limits of reference materials, however, it was difficult to confirm whether or not such strategic experiences were actually led to the publication of the books on military art and science, or how many books on military strategies and tactics had been published up until the end of Goryeo Dynasty. But, the facts that there were not many publications of the books on military strategies during the era of Three Kingdoms and of Goryeo Dynasty don't mean that Korean military science had entirely relied upon the Chinese military art and science. For instance, such strategies, tactics and leaderships as exhibited in the process of the Great Victory at Salsu River ("Salsu Daecheop") achieved by General Eulji Mun-deok, as well as the Great Victory at Gwiju ("Gwiju Daecheop") achieved by General Kang Gam-chan could never happen by chance.