• Journal of Korean Society of Coastal and Ocean Engineers
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• v.14 no.1
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• pp.8-18
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• 2002

In this paper, wave energy absorption of OWC(oscillating water column) device is analyzed. The analytic model consists of a partially immersed circular vertical cylinder open at its end and an air turbine connected with the air chamber. The boundary value problem is decomposed into scattering problem related to scattering by an incident wave in the absence of a pressure variation and radiation problem describing the flow due to an oscillating pressure in the absence of an incident wave. By invoking the continuity of an air flow inside the chamber, the oscillating pressure in a chamber is derived. With oscillating pressure, the mean power absorbed by OWC device and the capture width are obtained. In numerical calculation, the induced volume flux across the internal free surface of the chamber in the scattering and radiation problem and the maximum capture width are compared with various design parameters such as radius and submergence depth of chamber and wave conditions. The maximum capture width obtained by choosing the optimal value of turbine constant occurs at the first resonant mode (Helmholtz mode) among the natural frequencies of a circular cylinder chamber.

• Journal of the Korean Society for Nondestructive Testing
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• v.19 no.3
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• pp.189-199
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• 1999

The resonance scattering of acoustic waves from the cylindrical shells of nuclear fuel rods coated with oxide layers has been theoretically modeled and numerically analyzed for the propagation characteristics of the circumferential waves. The normal mode solutions of the scattering pressure of the coated shells have been obtained. The pure resonance components have been isolated using the newly proposed inherent background coefficients. The propagation characteristics of resonant circumferential waves for the shells coated with oxide layers are affected by the presence and the thickness of an oxide layer. The characteristics have been experimentally confirmed through the method of isolation and identification of resonances. The change of the phase velocity of the $A_1$ circumferential wave mode for the coated shell is negligible at the specified partial waves in spite of the presence of the oxide layer and the increase in coating thickness. Utilizing the invariability characteristics of the phase velocity of the $A_1$ mode, the oxide layer thickness of the coated shells can be estimated. A new nondestructive technique for the relative measurement of the coating thickness of coated shells has been proposed.

• Korean Journal of Poultry Science
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• v.17 no.4
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• pp.255-268
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• 1990

This study was carried out to investigate the time-trends of genetic parameters of the dosed flock population which selected for improving egg production. Data for two layer pure lines, Line-W (Single Comb White Leghorn) and Line-B (brown layer) which have been maintained at the Mani Breeding Farm were collected from 1980 to 1985 during 5 generations. The effective number of parents per generation ranged from 148 to 366 in Line-W and 85 to 355 in Line-B, and the cumulative expected inbreeding coefficients during 5 generations of selection were 15％ and 1.6％. So inbreeding could not be considered a critical factor on estimating the genetic parameters, heritabilities and genetic correlations Heritabilities of EN 300 and EN 400, primary two selected traits were significantly decreased during 5 generations but the estimates of the other 03its not showed the consistent decreasing pattern significantly. No time trends of probable consequence were evident in the genetic correlation coefficients of the traits studied. The reason for that situation was attributed to the fact that selection was conducted for multiple objectives and the relative importance of selection for the studied traits were not consistent by generations.

• Progress in Medical Physics
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• v.13 no.1
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• pp.37-43
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• 2002

Effect of scatter media materials and thickness, located between radioactivity and small gamma camera, on imaging characteristics was evaluated. The small gamma camera developed for breast imaging was consisted of collimator, NaI(T1) crystal(60$\times$60$\times$6 ㎣), PSPMT(position sensitive photomultimplier tube), NIMs and personal computer. Monte Carlo simulation was performed to evaluate the system sensitivity with different scatter media thickness(0~8 cm) and materials(air and acrylic) with parallel hole collimator and diverging collimator. The sensitivity and spatial resolution was measured using the small gamma camera with the same condition applied to the simulation. Counts was decreased by 10%(air) and 54%(acryl) with the parallel hole collimator and by 35%(air) and 63%(acryl) with the diverging collimator. Spatial resolution was decreased as increasing the thickness of scatter media. This study substantiate the importance of a gamma camera positioning and the minimization of the distance between detector and target lesion in the clinical application of a gamma camera.

• Proceedings of the Korean Society of Fisheries Technology Conference
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• 2001.10a
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• pp.354-355
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• 2001

국내 수산자원은 어선세력의 증가와 어획기술의 발전에 의한 어획합력, 연안역 개발에 의한 산란 성육장의 축소 등으로 1970년대 이후로 자원감소의 현상이 현저하게 나타나고 있다. 효율적 자원조성을 위한 방안으로서 치어방류 사업이 근년 본격적으로 시행되면서 1999년에는 약 2,300만 마리의 치어방류를 하고 있으며, 방류효과에 대한 긍정적 평가가 조사 보고 되고 있다 (Sung, 1998). (중략)

• KOREAN POULTRY JOURNAL
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• v.34 no.5 s.391
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• pp.79-82
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• 2002

육계농장에서는 SE(Salmonella Enteritidis)감염도 있지만, 오히려 SE이외의 여러 가지 요인에 의한 혈청형 살모넬라에 오염되는 경우가 많다. 현재 육계농장에서는 계군을 살모넬라로부터 완전히 차단하는 것은 어렵다고 생각하고 있고, WHO에서도 살모넬라 오염을 가능한 한 감소시키는 쪽으로 살모넬라 대책의 지침으로 정하고 있다. 그러나, SE 및 ST(Salmonella Typhimurium)등 사람에게 병원성을 나타내는 혈청형에 의한 계군의 살모넬라 감염오염은 공중위생의 견지에서 완전히 제거하지 않으면 안되다. 여기에서 출하 및 수송시의 대책, 사료의 살모넬라 오염의 중요성 등 산란계와는 다른 점을 지적하면서 기하고자 한다. 일상의 위생관리에 관한 양계장에서의 대책과 살모넬라 검사법에 대하여는 제외하였다.

• Korean Journal of Poultry Science
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• v.30 no.4
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• pp.259-267
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• 2003

Two experiments were conducted to investigate the effect of betaine on egg production, lipid metabolism, and osmoregulation in 18-to 42-week-old ISA Brown laying hens. In experiment 1, three hundred and sixty one hens were fed a com-soy basal diet contailing 16% crude protein (CP), 2800 kcal/kg metabolizable energy (ME), 0.33% methionine, and 0, 300, 600, or 1200 mg betaine per kg diet. Egg production, egg weight, feed consumption, feed conversion, and egg quality were measured every eight weeks. Betaine concentration in live and egg were determined along with serum cholesterol, abdominal fat, total serum protein and albumin levels. In experiment 2, twenty thirty-three-week-old laying hens were fed the same diets as those used in experiment 1 in individual cages and the amount of feed and water consumption were measured for two weeks. At the end of experiment 2, all birds were killed to determine blood plasma and ileal osmopressure, arginine vasotocin (AVT), and liver moisture content. In experiment 1, egg production between the treatments during the first eight weeks were not different, whereas the significant increment of egg production were noticed in the birds fed more than 600 ppm betaine after reaching the peak egg production stage (p<0.05). The egg weight was reduced significantly by the betaine supplementation for the first 8 weeks (p<0.05). Feed conversion tended to improve by betaine supplement. Egg quality was not enhanced by betaine supplementation. Liver betaine level increased with betaine feeding compared to the control but betaine concentration in eggs decreased with betaine supplementation. Betaine supplementation elevated the level of serum total cholesterol and triglyeerides compared to the control. Abdominal fat content was increased by betaine supplementation, whereas liver fat content decreased. In experiment 2, water consumption significantly increased in hens fed diets containing 300 and 600 mg betaine/kg (p<0.05) and osmotic pressure of ileal digesta increased with betaine supplement. Liver moisture content was not affected by betaine, but AVT increased in hens fed betaine. The overal results suggested the possibility of using betaine as a feed additives in the laying hens beacuse of its positive contribution to improving egg production and other metabolic parameters related to lipid metabolism.

• Proceedings of the Korean Society of Fisheries Technology Conference
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• 2010.05a
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• pp.103-106
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• 2010

• Proceedings of the Korean Society of Fisheries Technology Conference
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• 2010.05a
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• pp.131-134
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• 2010

• Proceedings of the Korea Electromagnetic Engineering Society Conference
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• 2001.11a
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• pp.20-24
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• 2001

Two types of radiative coupling in the 2-dimensional aperture to scatterer coupling problems are described with an emphasis on the main difference between the two types. In particular, detailed comparison is made from the viewpoint of the Quality factor between two types.