• Title/Summary/Keyword: 산란형

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Acoustic Scattering Analysis of a Spherical Shell using a coupled FE-BE Method (결합형 유한요소-경계요소 기법을 사용한 구형체의 음향 산란 해석)

  • Jarng, Soon-Suck
    • Journal of Sensor Science and Technology
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    • v.7 no.1
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    • pp.9-16
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    • 1998
  • This paper describes how the directivity pattern of the scattered sound pressure is distributed when a plane acoustic wave is incident on a rigid or soft spherical shell underwater. A coupled Finite Element-Boundary Element method is developed as a numerical technique. The result of the coupled FE-BE method is agreed with theoretical solution for algorithmic confirmation.

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Preference, Development and Fecundity of the Brown Planthopper(Nilaparvata lugens St${\aa}$l) Biotypes Fed on Different Cultivars of Rice with Various Resistance Gence (벼의 품종저항성이 벼멸구 각 생태형의 선호성, 발육 및 증식능력에 미치는 영향)

  • 박영도;송유한
    • Korean journal of applied entomology
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    • v.27 no.2
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    • pp.87-93
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    • 1988
  • Some attempts were made to investigate the biological characteristics of the brown planthopper(BPH), Nilaparvata lugens St${\aa}$l, biotypes in terms of perference in feeding oviposition on rice field, egg and nymphal periods, egg hatchability, emergemce ratio, growth index, adult lingevity and gecundity fed on 60-day-old rece cultivaes with different resistance genes. Feeding and oviposition perference of the three BPH biotypes on Dongjinbyeo with no resistance gene were shown very higher than on rice cultivars with resistance genes. Those of biotype-2 on Cheongcheongbyeo with bph 1 gene and bitype-3 on Milyang 63 with bph 2 gene were relatively high, however, they were still remarkably lower than those of Dongjibyeo. The egg and nymphal periods of the three BPH biotyes on Milyang 23 were shorter than on the other rice cultivars. The periods of biotype-2 on Cheongcheongbyeo and biotype-3 on Milyang 63 were as short as those of the three BPH biotypes on Milyang 23. The egg hachability, emergence ratio, and growth index of the three BPH bioyoes on Milyang 23 were higher than on the other rice cultivars and those of biotype-2 on Cheongcheongbyeo and biotyoe-3 on Milyang 63 were as high as on Milyang 23. The female adult longevity of the BPH biotype-1 on Milyang 23 was longer than on the other cultivaes, and that of biotype-2 on Cheongcheongbyeo and bioty-3 an Milyang 63 were as ling as on Milyang 23. The number of egg laid by a female of the three BPH biotypes were greatly increased on Milyang 23. Those of biotype-2 on Cheongcheongbyeo and biotype-3 an Milyang 63 were also greatly increased.

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A Study of Analysis on Comparison of Laying Performance and Disease Occurrence of Welfare Approved Farms of Laying Hens with Housing Type (산란계 동물복지 인증농가의 사육형태와 품종별 생산성 및 질병발생 비교 분석 연구)

  • Hong, Eui-Chul;Kang, Hwan-Ku;Park, Ki-Tae;Jeon, Jin-Joo;Kim, Hyun-Soo;Park, Sung-Bok;Kim, Chan-Ho;Suh, Sang-Won;Kim, Sang-Ho
    • Korean Journal of Poultry Science
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    • v.44 no.2
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    • pp.143-149
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    • 2017
  • This study was carried out to collect basic data on the egg laying performance and disease occurrence on animal welfare-approved farms (AWAF) for laying hens with different housing types (windowless, open, and free-range house) and strains (Hy-line, Lohmann). Age at first egg laying was 151 d in the windowless house and 141 d in both the open and free-range houses, and the percentage peaks of each farm were 91.8%, 92.9%, and 86.3%. Average egg production according to housing types were 70.9%, 77.4%, and 65.6% at 18~38 wk old and 91.1%, 90.1%, and 76.2% at 32~36 wk. The average dirty and cracked egg ratio of the windowless, open, and free-range houses was 2.84%, 1.15%, and 0.23%, respectively. Mortality in the open house was lower than the other house types. Age of first egg laying for the Hy-line strain was 155 d and that for the Lohmann strain was 157 d, and the percentage peaks of the two strains were 92.9% (252 d) and 87.2% (237 d), respectively. Average egg production of the strains was 83.7% and 76.9%, respectively. The average dirty and cracked egg ratio of the Hy-Line and Lohmann strains was 3.85% and 2.97%, respectively. Mortality of the Hy-Line strain was lower than that of the Lohmann strain. There were significant differences (P<0.05) in the egg weight, HU, and egg yolk color of chickens raised in the open house compared with those of chickens raised in the other house types. In terms of antibody titer, that for Newcastle disease in open house chickens was lower than that of chickens raised in windowless and free-range houses. The antibody titer for low pathogenic avian influenza, avian infectious bronchitis, and avian pneumovirus was high at over 3.0 in all three farms. SG, Salmonella enteritidis, Salmonella pullorum, fowl adenovirus infection, and infectious laryngotrachitis were not detected in any of the three house types. The number of AWAF for laying hens has continuously increased in Korea, but there is currently little data on the housing types used on the AWAF for laying hens. Therefore, the results of the present study, in which analyzed the laying performance and disease occurrence on AWAF for laying hens, can use as basic data for the improvement of performance and prevention of disease on further AWFA for laying hens.