• Proceedings of the Korea Society of Poultry Science Conference
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• 2004.11a
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• pp.107-108
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• 2004

산란계 육성기 제한시기 및 제한강도가 육성기 발육형태 및 산란생산성 반응을 구명하고자 1일령 갈색 산란 실용계 Isa-brown 1,000수를 공시하여 70주간 사양시험을 실시하였다. 사료급여 방법은 자유채식구와 제한급이구 9처리를 두었는데, 제한시기는 4, 6 및 8주령으로 하였고 제한강도는 각 시기별 70 %, 85 % 및 12주령 기준으로 70 %에서 85 %로 하는 처리를 두었다. 육성기 사료섭취량은 제한급이시기가 빠를수록 제한강도가 강할수록 자유채식구에 비하여 유의적으로 낮게 나타났다(P<0.05). 산란생산성은 4주령, 85 %구와 6주령 70 % 및 6주령 70 $\longrightarrow$ 85 % 전환구가 가장 우수한 것으로 나타났다. 계란 난각의 품질은 제한급이구가 산란후기에 자유채식구 대비 양호한 것으로 나타났다. 이상의 결과에서 육성기 제한급이는 육성기 사료섭취량을 절감할 수 있으며 생산성과 난각질 향상에 기여할 것으로 판단된다.

• The Korean Journal of Malacology
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• v.9 no.1
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• pp.33-38
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• 1993

강원도 춘천군, 명주군, 평창군에서 채집한 산골조개(pisidium (Neopisidium) coreanum)의 발생형태 및 산란시기에 대한 조직학적 결과는 다음과 같다. 산골조개는 난태생이고 아가미를 보육장으로 이용하여 발생을 하였다. 유패는 한 개체의 성패내에서 최고 19마리까지의 유패를 보유하였으며 방출 즉시 독깁 생활을 하였지만 수관의 구별은 어려웠다. 산란은 일년내내 할 수 있으며 생식소내에서 난소와 정소의 배우자 발생 시기가 다른 것으로 보아 자가수정을 하지 않는것으로 관찰되었다.

• Journal of the Korean Data and Information Science Society
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• v.22 no.5
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• pp.903-910
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• 2011

The von Bertalanffy growth function (VBGF) is the result of the antagonistic effects of anabolism and cataboliem. However VGBF has limitations for describing the growth of continuous spawning fishes. In the present work, a new equation is proposed where the growth parameter Kis substituted by a function related to the sea surface temperature of spawning period. Examples for natural population of Pacific Anchovy are presented.

• Korean journal of applied entomology
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• v.44 no.3 s.140
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• pp.231-235
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• 2005

This study was conducted to obtain the optimal spray time for Pseudaulacaspis prunicota (Maskell) (Homoptera: Diaspididae) in early seaon in Jeju. Oviposition time of overwintered females and activity of hatched nymphs of P. prunicola were monitored, and the phenology data were compared with the outputs estimated by a degree-days model of P. pentagona (Targioni-Tozzetti)). Overwintered females of P. prunicola began to lay eggs from mid to late April, and the eggs started to hatch from early May followed by the active migration of the hatched nymphs during mid May. The phenological events of P. prunicola in early season were likely comparable with those of P. pentagona reported in southern Korea and in central Japan. A degree-day model, which predicts the proportion of >50% hatched egg batches of P. pentagona (y=1[exp(-(-a+bx))]; y, proportion; x, degree-days based on $10.5^{\circ}C$ from 1 January; a=-18.80 and b=0.073), accurately described the migration time of P. prunicola hatched nymphs. Thus, it is considered that the degree-day model can be used for predicting the optimal spray time for P. prunicola in early season.

• Korean Journal of Soil Science and Fertilizer
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• v.45 no.4
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• pp.503-510
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• 2012

Microwave radar can penetrate cloud cover regardless of weather conditions and can be used day and night. Especially a A ground-based polarimetric scatterometer operating at multiple frequencies can continuously monitor the crop conditions. We analyzed scattering characteristics of rice and soybean using pauli decomposition method. Surface scattering (${\alpha}$) is the dominant component over the entire stages for all bands and pauli decomposition value was the highest for L-band. Double bounce scattering (${\beta}$) and volume scattering (${\gamma}$) were approximately equal for C-band and volume scattering was higher than double bounce scattering for X-band in rice field. In soybean, double bounce scattering becomes higher than volume scattering during the R2 stage (DOY 224) and there was a significant difference between the two components after the R4 stage (DOY 242) for L-band. The maximum growth stage of soybean can also be detected using L-band double bounce scattering. The peak of double bounce effect coincides with the peak of growth biophysical variables on DOY 271. We found that pauli decomposition can provide insight on the relative magnitude of different scattering mechanisms during the rice and soybean growth cycle.

• Korean Journal of Soil Science and Fertilizer
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• v.43 no.3
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• pp.374-383
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• 2010

Microwave radar can penetrate cloud cover regardless of weather conditions and can be used day and night. Especially a ground-based polarimetric scatterometer has advantages of monitoring crop conditions continuously with full polarization and different frequencies. Kim et al. (2009) have measured backscattering coefficients of paddy rice using L-, C-, X-band scatterometer system with full polarization and various angles during the rice growth period and have revealed the necessity of near-continuous automatic measurement to eliminate the difficulties, inaccuracy and sparseness of data acquisitions arising from manual operation of the system. In this study, we constructed an X-band automatic scatterometer system, analyzed scattering characteristics of paddy rice from X-band scatterometer data and estimated rice growth parameter using backscattering coefficients in X-band. The system was installed inside a shelter in an experimental paddy field at the National Academy of Agricultural Science (NAAS) before rice transplanting. The scatterometer system consists of X-band antennas, HP8720D vector network analyzer, RF cables and personal computer that controls frequency, polarization and data storage. This system using automatically measures fully-polarimetric backscattering coefficients of rice crop every 10 minutes. The backscattering coefficients were calculated from the measured data at a fixed incidence angle of $45^{\circ}$ and with full polarization (HH, VV, HV, VH) by applying the radar equation and compared with rice growth data such as plant height, stem number, fresh dry weight and Leaf Area Index (LAI) that were collected at the same time of each rice growth parameter. We examined the temporal behaviour of the backscattering coefficients of the rice crop at X-band during rice growth period. The HH-, VV-polarization backscattering coefficients steadily increased toward panicle initiation stage, thereafter decreased and again increased in early-September. We analyzed the relationships between backscattering coefficients in X-band and plant parameters and predicted the rice growth parameters using backscattering coefficients. It was confirmed that X-band is sensitive to grain maturity at near harvesting season.

• Journal of the Korean Society of Fisheries and Ocean Technology
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• v.33 no.2
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• pp.97-108
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• 1997

Variation of the catches and fishing grounds, and spawning ecology of Lophius litulon caught by large staw net were investigated from following as ; L. litulon caught through the year, and the peak in catches showed on January in winter, and the lowest catches showed on August in summer. The fishing grounds of L. litulon were located in the Yellow Sea and the East China Sea. And the main fishing ground was formed in the adjacent waters of Ilhyang-cho, where catches and CPUE were more than 50 M/T, 5 kg/haul, respectively, and the range of coefficient of variation(C.V) was 0.6~0.7. The spawning season of L. litulon was on March and April, when spawning area was formed in waters between Ilhyang-Cho and Cheju-Do. The fishing grounds distribution of L. litulon was obviously different with seasonal variation. Namely, in winter, the fishing grounds were mainly formed in the western waters of Cheju-Do, and on March and April( in spawning season), the fishing grounds were densely formed in the adjacent waters of Ilhyang-Cho, and after May, the fishing grounds were widely dispersed towards in the Yellow Sea and the East China Sea with temperature upgrade.

• Korean Journal of Fisheries and Aquatic Sciences
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• v.23 no.6
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• pp.425-438
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• 1990

Acoustic and ichthyoplankton data collected from Shelikof Strait in 1981, 1984 and 1985 were examined to determine spawning ground and period of walleye pollock, Theragra chalcogramma. Walleye pollock in the Gulf of Alaska migrated into Shelikof Strait for spawning during late winter and early spring. They entered Shelikof Strait via the warm and saline deep layer (continental slope water mass) in the southwestern channel, and major fish schools concentrated for spawning along the deep trough (250~300m) in the western part of the central strait. Peak spawning activity occurred there from late March to early April. Peak spawning time and area in Shelikof Strait varied little between years, despite difference in hydrography. Geographical advantages together with some oceanographic phenomena (reduced water transport and reduced mixed layer depth in spring) made that area an optimal spawning ground in the Gulf of Alaska during early April. After early April, spawning intensity decreased rapidly and the spawning area tended to expand to the northeast and southwest.

• Proceedings of the Korean Aquaculture Society Conference
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• 2003.10a
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• pp.60-60
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• 2003

릿테르개멍게는 척색동물문 해초강에 속하는 멍게류로서 고착생활을 하며, 보통 해조류나 히드라 등으로 덮여 있어 눈으로 식별하기가 어렵고, 생태 및 분류에 관한 연구만이 있을 뿐이다. 이 연구는 제주도 연안에 서식하는 릿테르개멍게의 번식생태에 대한 기초자료를 얻고자 배우자형성과정 및 생식소 발달 단계 등을 조직학적으로 조사하였다. 실험 재료는 제주도 용담 연안에서 2001년 11월부터 2003년 1월까지 매월 20개체씩 총 300개체를 채집하여 생식소의 조직학적 변화를 관찰하였다. 릿테르개멍게는 자웅동체로서 생식소는 체벽부에 붙어 있고, 성숙시기에 난소는 적색을, 정소는 유백색을 띠고 있다. 생식소와 체벽부를 포함해 절단된 조직표본에서 보면 외측체벽은 근섬유를 포함한 섬유성결합조직이 발달해 있고 여기에 이어진 방형의 난소낭과 그 주변부에 자리 잡고 있는 여러 개의 정소낭을 식별할 수 있었다. 생식소 발달 및 배우자형성과정, 월별 생식소변화를 토대로 생식주기를 구분하면 성장기 (3-5월),난황기 (5-7월), 성숙기 (7-11월), 방출기 (11-2월), 회복기 (1-3월)로 구분되었으며, 주 산란시기는 11-1월로, 연중 1회의 산란시기를 갖는다.

• Proceedings of the Korean Society of Fisheries Technology Conference
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• 2003.05a
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• pp.380-381
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• 2003

석패과 종의 발생은 체내수정을 하며 산란시기는 계절에 따라 차이가 나는 것으로 알려져 있다 이들 종들은 아가미내에서 피면자 시기에 해당되는 유생인 글로키디움까지 발생 시기를 거친 후 유생이 체외로 방출되면 물고기 둥 수서생물에 부착하여 일정기간 기생생활을 거쳐 유패로 탈락하면서 독립생활을 하게 된다. 또한 석패과 유생의 발달과 분산의 형태는 곧 종의 수명과 지리적 분산의 중요한 역할을 하는 것으로 알려져 있다 (Jackson, 1974). (중략)