함금속 산성염료의조합사용시 염액재사용에 관한 연구

학위논문(석사)--서울대학교 대학원 :섬유고분자학과,1998.Maste

Inorganic Nutrient Removal Efficiency of Aquatic Plantsfrom Recirculating Aquaculture System

Inorganic nutrients such as nitrogen and phosphate compounds accumulate in recirculating aquaculture systems. These nutrients must be removed from the system before they affect pH and fish health. For this purpose, aquatic plants are a simple and inexpensive method of removal. There are four commonly used aquatic plants: Eichhornia crassipes (water hyacinth), Pistia stratiotes (water lettuce), Hygrophila angustifolia, and Hydrocotyle leucocephala in freshwater recirculating aquaculture systems in Korea, but their efficiencies are not known. Therefore, removal efficiencies of inorganic nutrients from a freshwater recirculating aquaculture water with four commonly used aquatic plants were tested. Removing efficiencies of TAN, N O2 [−10] -N, and N O3 [−10] -N of the plants in 210 L aquaria for 48-hour period were tested. The removing efficiencies of TAN, N O3 [−10] -N, and P O4 3− -P of the two most effective plants, water hyacinth and water lettuce, were also tested in 690 L (surface area of 1.55 m2 ) tanks under 2 different initial stocking densities, 4 kg and 6 kg, for 22 days. Proximate analysis major nutrients and N and P contents of the all plants were analyzed for calculating net removal weight of N and P by the plants. Water lettuce was the most effective for removing TAN, N O2 [−10] -N, and N O3 [−10] -N from the water for 48-hour period tested followed by water hyacinth and Hygrophila angustifolia. Water lettuce reduced TAN, N O2 [−10] -N, and N O3 [−10] -N concentration from 2.3 mg/L, 0.197 mg/L, and 21.4 mg/L to 0.4 mg/L, 0.024 mg/L and 17.4 mg/L, respectively while water hyacinth reduced them down to 0.6 mg/L, 0.029 mg/L and 17.9 mg/L, respectively. The concentrations of TAN, N O2 [−10] -N, and N O3 [−10] -N in Hydrocotyle leucocephala group were rather increased up to 3.7 mg/L, 5.7 mg/L and 48.2 mg/L, respectively. This is because the creeping stem of Hydrocotyle leucocephala had to be cut to meet stocking weight resulting in decaying of the stem in the aquaria during experiment. The net growth in weight of water hycinth and water lettuce of 4 kg each in the 1.55 m2 tanks for 22 days were 9.768 kg and 10.803 kg respectively, and those at initial weight of 6 kg each were 8.393 kg and 9.433 kg, respectively. The reason of lower net growth in the later group was restricted growth space. Nitrogen and phosphorus contents in water hyacinth were 2.89% and 0.27%, and those in water lettuce were 3.87% and 0.36%, respectively. Average quantities of removed N and P from 1.55 m2 tanks by water hyacinth for 22 days were 18.9 g and 1.75 g, while those by water lettuce were 36.8 g and 3.5 g, respectively. Therefore water lettuce showed much higher efficiencies for removing both N and P from recirculating aquaculture water than water hyacinth.33Nkciothe

Metabolic response of the fasted juvenile cod Gadus macrocephalus subjected to different water temperatures and photoperiods

A study was conducted to investigate the effect of water temperature and photoperiod on the oxygen consumption of the starved juvenile cod, Gadus macrocephalus (mean body weight 79.9±2.0 g) in order to assess metabolic response of this species at given conditions. The oxygen consumption rate (OCR) of G. macrocephalus was measured under&nbsp; the combination of four different water temperatures (7, 10, 13 and 16℃) and three different photoperiods (24L:0D, 12L:12D and 0L:24D) with an interval of 5 minutes for 24 hours using a continuous flow-through respirometer. In each treatment three replicates were set up. The OCRs increased with increase in water temperature under all photoperiod conditions (P<0.001). Mean OCRs at 7, 10, 13 and 16℃ ranged 793.7∼1108.4, 1145.7∼1570.3, 1352.8∼1742.5 and 1458.2∼1818.6 mg O2 kg-1 h-1, respectively. Mean OCRs of G. macrocephalus were the highest in continuous light (24L:0D) followed 12L:12D and 0L:24D photoperiod (P<0.001). Mean OCRs of fish exposed to the 12L:12D photoperiod was significantly higher during the light phase than during the dark phase under all temperature conditions (P<0.001). Q10 values ranged 3.19∼5.13 between 7 and 10℃, 1.41∼1.70 between 10 and 13℃ and 1.15∼1.35 between 13 and 16℃, respectively. Based on overall results, water temperature, photoperiod and their combinations exert a significant influence on the metabolic rate of juvenile cod. This study provides empirical data for estimating the amount of oxygen demand and managing the culture of cod under the given temperatures and photoperiods.2

Effects of Rotational Speed and Hydraulic Residence Time on theAmmonia Removal of a Rotating Biological Contactor (RBC)

Performance of a biological filter, the rotating biological contactor (RBC), is affected by rotational speed and hydraulic residence time (HRT). A RBC with a disc diameter of 62 cm, total surface area of 48.28 m2 , volume of 0.34 ㎥, and submergence ratio of 35.4% was tested for the combinations of five rotational speeds (1, 2, 3, 4 & 5 rpm) and three HRT (0.5, 1.0 & 2.0 hr) to find out the maximum removal efficiencies of total ammonia nitrogen (TAN) and nitrite nitrogen of a simulated recirculating aquaculture system. Ammonia loading rate in the system was 25 g of TAN/ ㎥. day. Removal efficiencies were checked when TAN concentrations in the system stabilized for 3 days in each treatment. The concentration of TAN in the system decreased with increasing rotational speed of the RBC up to 4 rpm in all HRT (P 2 [−10] -N) in the system decreased with increasing rotational speed in all HRT while that in the system increased with increasing HRT in all rotational speeds. The ranges of NO 2 [−10] -N concentrations at HRT of 0.5, 1.0, and 2.0 hr in the system were 0.26~0.32, 0.31~0.56, and 0.43~l.45 mg/L, respectively. The ranges of daily removal rates of TAN in this system were 20.03~23.0 g TAN/㎥ㆍday and those of nitrite nitrogen were 19.65~30.25 g NO 2 [−10] -N/㎥ㆍday.33Nkciothe

Effect of temperature on endogenous and postprandial ammonia excretion of dark-banded rockfish Sebastes inermis

The effect of water temperature on daily pattern and rate of total ammonia nitrogen (TAN) excretion in juvenile dark-banded rockfish Sebastes inermis (mean body weigh: 14.8±0.3 g) under fasting and feeding conditions was investigated. Fish were acclimated over 10 days under three different water temperatures (15, 20 and 25℃). After 72 hours of fasting, fasting TAN excretion was measured at each temperature. And then, to investigate post-prandial TAN excretion, fish were hand-fed with a commercial diet containing 47.7% crude protein for 7 days, two times daily 09:00 and 17:00 h. Water was sampled for both the inlet and outlet of chamber every 2 h over a 24 h period. Both of fasting and post-prandial TAN excretion increased with the increase of water temperature (P<0.05). Mean fasting TAN excretion rates at 15, 20 and 25℃ were 8.1, 9.0 and 9.2 mg TAN kg fish-1 h-1, respectively. The value of 15℃ was lower than those of 20 and 25℃ (P<0.05), but there was no significant difference between 20℃ and 25℃. Mean post-prandial TAN excretion rates at 15, 20 and 25℃ were 20.1, 22.9 and 23.4 mg TAN kg fish-1 h-1, respectively. A peak post-prandial TAN excretion rate occurred after 12 hours from the first feeding at 15℃ (mean 28.7 mg TAN kg fish-1 h-1), 20℃ (33.7 mg TAN kg fish-1 h-1) and 25℃ (36.8 mg TAN kg fish-1 h-1), respectively. The TAN loss for ingested nitrogen at 15℃ (36.2%) was lower than that of 20℃ (40.8%) and 25℃ (41.7%). As overall results, water temperature exerts a profound influence on the nitrogen metabolism of juvenile dark-banded rockfish.2

공동에 포획된 원자를 이용한 양자정보처리

학위논문(박사) - 한국과학기술원 : 물리학과, 2005.2, [ vi, 64 p. ]Quantum information processing has originated from new insight that a quantum state serves as a sort of information. The peculiar nature of the quantum world opens up the way to achieve a number of tasks which have no classical counterparts. They include perfectly secure communication, exponential speedup of some computations, and so on. Despite the fruitful results, quantum information processing is very difficult to be realized with a physical system due to the sensitivity of quantum states and quantum operations. In this dissertation, quantum information processing is briefly introduced, and systems of cavity-trapped single atoms are considered as candidates for physical realization of it. Especially, various single photon input-output processes in the atom-cavity system are presented, and it is shown that they can serve as the essential ingredients for various modes of quantum information processing, such as for conversion and controlled unitary operation between an atomic qubit and a photonic qubit. In that context, new schemes for quantum teleportation of atomic states and for quantum gates between distant atomic qubits are proposed and analyzed both theoretically and numerically concerning various physical and experimental aspects.한국과학기술원 : 물리학과