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        검색결과 2,116

        1262.
        1999.03 KCI 등재 구독 인증기관 무료, 개인회원 유료
        오하이오 중부에서 풍속이 0.5m.s-1인 경우는 매우 드물었으며, 5년 평균 풍속은 약 2.5 m.s-1인 것으로 나타났다. 최고 기온이 35t인 오하이오주의 대표적인 여름에 온실 내의 여섯 곳에서 측정된 기온의 최대범위는 1.7℃, 온실 내외 기온의 최대차는 3.5℃인 것으로 나타났다. CFD 모델에서의 온도 분포를 분석한 결과, 온실의 환기 회수가 0.9 회/분 이상일 때 실내 공기가 외부 기온을 2.8℃이상 초과하는 경우는 없었던 것으로 예측되었다. 풍향과 풍속에 따라서 각각의 환기구들의 효율성이 영향을 받는 것으로 나타났으며, 특히 환기창을 통해 유입되는 강한 바람에 의하여 발생하는 공기의 소용돌이들은 지붕창들의 효율성에 많은 영향을 미치는 것으로 예측되었다. CFD model은 서쪽에서와 동쪽에서 불어오는 바람이 각각 2.1 m.s-1와 3.5 m.s-1이상일 때 이 연동형 온실은 적정한 자연 환기량을 취할 수 있다고 예측하였다. 측면창 바로 옆에 위치한 식물군과 벤취에 의해 측면창을 통한 자연적인 공기의 유입이 방해를 받기 때문에, 바람이 서쪽에서 불어올 때 식물군이 없을 때보다 평균 12%의 환기량의 감소 결과를 가져오는 것으로 예측되었다. 식물군은 공기의 유입창의 위치보다 약간 낮은 곳에 위치하여야 하며, 유입창을 너무 높이 설치하면 측면창을 통해 유입되는 공기는 가장 근접한 지붕창을 통해 대부분이 배출되는 것으로 예측되었다. 연동형 자연환기식 온실에 있어서 바람이 불어오는 쪽의 측면창들과 바람의 반대쪽을 향한 지붕창들의 혼합형이 가장 효율적인 온실 설계인 것으로 예측되었다.
        4,000원
        1268.
        1998.09 KCI 등재 구독 인증기관 무료, 개인회원 유료
        극심한 고온으로 인해 정상적인 작물의 재배가 어려운 여름철의 온실 내 기온을 억제시키기 위한 방법 중 가장 효율을 인정받고 있는 증발냉각법은 실내 습도의 증가로 인해 그 사용에 제한을 받게 된다. 본 연구에서는 온실에서 증발냉각법의 냉방효율을 높이기 위한 방법으로 냉수파이프를 설치하여, 그 열적 특성을 분석하고, 제습효과를 조사하였으며, 그 결과를 요약하면 다음과 같다. 동파이프와 아연도금스틸파이프의 총열전달량을 비교한 결과, 동파이프가 다소 크게 나타났으나, 유의성이 없었으며, 두 가지 파이프 모두 이론값 보다 실측값이 더 작게 나타났다. 냉수파이프 표면에 응축되어 제거된 수증기의 양은 동파이프와 아연도금스틸파이프 사이에서 큰 차이를 보이지 않았으나, 두 가지 파이프 모두에서 제습효과는 충분히 큰 것으로 나타났다. 냉수파이프를 설치함으로써 증발냉각시스템의 냉방효율을 평균 48%만큼 높일수 있으며, 평균 1.3℃만큼의 실내기온을 추가로 냉각시킬 수 있는 것으로 예측되었다. 또한, 냉수파이프를 이용해 증발냉각시스템의 가동으로 인한 실내의 과습문제를 해결하기 위해서는 파이프표면의 응축된 수분을 효과적으로 제거할 수 있는 장치나 방법에 대한 추가적인 연구가 필요할 것으로 판단된다.
        4,000원
        1269.
        1998.09 KCI 등재 구독 인증기관 무료, 개인회원 유료
        5,500원
        1271.
        1998.09 KCI 등재 구독 인증기관 무료, 개인회원 유료
        Polyoxyethylene monooleate was prepared by addition of ethylene oxide to oleic acid. And also, polyoxyethylene monooleate type oil dispersant was prepared by blending polyoxyethylene monooleate, n-paraffine, sorbitan monooleate, sorbitan monopalmitate, and palm oil. Dispersion efficiency test was carried out by vertical shaking flask and swirling flask methods. Low toxic oil dispersant was prepared with polyoxyethylene monooleate, which has high biodegradability and excellent dispersion efficiency on crude oils and weathered W/O emulsions with high viscosity, and its dispersion efficiency was measured to various crude oils and weathered oils.
        4,000원
        1272.
        1998.08 KCI 등재 구독 인증기관 무료, 개인회원 유료
        This experiment was carried out to investigate the factors affecting superovulation in rabbits and to determine the effect of pFSH and PMSG on ovarian superovulatory responses and embryo production, and the effect of superovulation treatment with a single injection of pFSH dissolved in polyvinylpyrrolidone on the ovarian responses and the embryo quality. The results obtained were suonmerized as follows: Superovulatory response resulted in significantly (P<0.05) higher ovulation rates and more embryos in spring or autumn, compared with summer or winter. Repeated superovulatory treatments with PMSG leaded to a significantly(P<0.05) decreased number of total follicles and recovered ova. Superovulation with pFSH resulted in the higher number of ovulated follicles and recovered ova than with PMSG. A single subcutaneous injection of pFSH dissolved in 25% PVP resulted in the more ovulation points(33.2) and recovered embryos(30.2), which were comparable to the multiple injections of pFSH(44.8 vs 37.7).These results indicated that the treatment with a single injection of FSH dissolved in PVP was an efficient and simple alternative method to the conventional multiple FSH injections for superovulation in rabbits.
        4,200원
        1273.
        1998.08 구독 인증기관 무료, 개인회원 유료
        5,100원
        1276.
        1998.06 KCI 등재 구독 인증기관 무료, 개인회원 유료
        본 논문은 바닥판을 고려한 3차원 골조 구조물의 효율적인 연직 진동 해석법을 제안한다. 바닥판의 영향을 고려하면 구조물의 진동해석을 좀더 정확히 수행할 수 있는 반면, 면요소의 사용에 따른 많은 자유도의 사용으로 많은 해석시간과 기억용량이 필요하게 된다. 따라서, 행렬응축기법을 사용하여 적절한 요소분할 및 주자유도 선택 기법을 제안하였으며, 대형요소를 사용하여 정확화된 일반적인 건물의 동적해석에 적용하여 입력 데이터의 작성을 간단히 하고 동적해석을 빠르고 신뢰할 만한 결과를 얻을 수 있는 기법에 대하여 연구하였다.
        4,300원
        1277.
        1998.04 KCI 등재 구독 인증기관 무료, 개인회원 유료
        This study was carried out to establish an effective system for embryo transfer techniques by analyzing several factors affecting in-vivo embryo transfer in Korean cattle Embryos were transferred into a toral of 301 recipients. The results obtained in studies on the factors affecting pregnancy rate after embryo transfer by condition of transfer time were as follows ; 1. The pregnancy rate by the seasons of transferred fresh and frozen embryos were not different, but the pregnancy rate was slightly higher in summer(80.8%). 2. The pregnancy rate by the days of embryo transfer after estrus were not different when fresh embryos were transferred, but the pregnancy rate was highest at 8 days when frozen embryos were transferred(P<0.01, 40.0%). 3. The pregnancy rate at estrus synchronization was remarkably higher with PGF treated than natural (P<0.05, 70.4%, 43.4%). 4. The pragnancy rate by the degree of estrus synchronization was best when the estrus was synchronized in both fresh and frozen embryos (83.3% and 29.7%, respectively), but the pregnancy rate was not different among 2 days. But the pregnancy rate of frozen embryos were slightly higher when the recipients exhibited estrus earlier than donors.
        4,000원
        1278.
        1998.04 KCI 등재 구독 인증기관 무료, 개인회원 유료
        This study was carried out to establish an effective system for embryo transfer techniques by analyzing several factors affecting in-vivo embryo transfer in Korean cattle. Embryos produced in-vivo were transferred into a total of 301 recipients The results obtained in studies on the factors affacting pregnancy rate after embryo transfer by condition of recipients were as follows ; 1. The pregnancy rate by age and parity of recipients showed high in 5~8 and over 12 years old(72.7~73.9%), and 3rd~4th parity(82.1%) for fresh embryos(P<0.05). The pregnancy rate did not differ by age and parity of recipients in frozen embryos. The pregnancy rate of frozen embryos tended to be similar to that of fresh embryos(38.5% and 25.0~36.7%). 2. The number of observation for normal estrus cycles of recipients did not differ In pregnancy rate between one and 2 times in fresh embryos(64.9%, 69.8%). The pregnancy rate by transferred frozen embryos showed significantly higher after 2 times of observation(P<0.05, 16.3%, 37.5%). The pregnancy rate by days open did not differ between fresh and frozen embryos. But the pregnancy rate was slightly higher in 12 months and 6 months of days open for fresh and frozen embryos, respectively(70.1~71.1% and 24.5%, respectively). 3. The pregnancy rate of transferred fresh and frozen embryos into right and left side of uterine horn did not differ(62.1% : 65.9% 25.0% : 24.3%, respectively). The pregnancy rate by the grade of CL was not different in fresh embryos, but the pregnancy rate was significantly higher in the grade A than B for frozen embryos(P<0.01, 43.2%, 16.2%).
        4,000원
        1279.
        1998.04 KCI 등재 구독 인증기관 무료, 개인회원 유료
        This study was carried out to establish an effective system for embryo transfer techniques by analyzing several factors affecting in-vivo embryo transfer in Korean cattle. Embryos produced in-vivo were transferred into a total of 301 recipients. The results obtained in studies on the factors affecting pregnancy rate after embryo transfer by condition of embryos were as follow ; 1. The pregnancy rate of 301 recipients was 45.2% and higher with fresh embryos than with frozen embryos(63.5% : 21.4%, P<0.01). Embryos superovurated by FSH-P had slightly greater than by SUPER-OV in pragnancy rate, athough these were no difference between two treatments. 2. The pregnancy rates of transferred morulae and blastocysts showed no difference between fresh and frozen embryos(63.5% : 63~6% ; 20.0% : 25.8%). However, the pregnancy rates by quality of flesh and frozen embryos were significantly different(P<0~05). The pregnancy rates were outstandingly high in the grade A, B of fresh embryos(59.0~66.4%), and in the grade A of frozen embryos(43.6%). 3. The number of transferred embryos showed no difference in pregnancy rate, but when frozen embryos transferred, the pregnancy rate was slightly higher with two embryos than that with one embryo.
        4,000원
        1280.
        1998.04 KCI 등재 구독 인증기관 무료, 개인회원 유료
        This study was to determine the effect of ionomycin and 6-dimethylaminopurine (6-DMAP) and/or elcetrical stimulation on the oocyte activation and production of rabbit nuclear transplant embryos. The oocytes were collected from the oviduct of superovulated rabbits at 14 h post hCG injection and cultured in TCM-199 containing 10% FBS until 19 h post hCG injection. To determine the optimum concentration and exposure time of 6-DMAP, some oocytes were activated with 5 M ionomycin for 5 min and then in 2.0 mM 6-DMAP for 0.5 to 3.0 h, or in 1.0 to 3.0 mM 6-DMAP for 2.0 h. Other control oocytes were stimulated electrically(3X, 1.25 kV/cm, 60 sec) in 0.3 M mannitol solution supplemented with 100 M CaCl and MgCl. The nuclear donor embryos of 8-cell stage were synchronized to G phase of 16-cell stage, and the recipient cytoplasms were obtained from removal of the first polar body and a portion of membrane bound cytoplasm of the oocytes collected at 15 h post hCG injection. A separated blastomere was injected into the perivitelline space of the enucleated oocytes. The oocytes injected with nucleus were cultured until 19 h post hCG and then electrofused and activated by electrical stimulation with or without ionomycin and 6-DMAP. These nuclear transplant embryos were cultured in TCM-199 containing 10% FBS in 39˚C, 5% CO2 incubator for 120 h. For the oncytes activated parthenogenetically with electrical stimulation with or with-out ionomycin and the various concentration of exposure time of 6-DMAP, the highest cleavage(92.3%) and development to blastocyst stage(41.0%) were resulted from the oocytes activated by ionomycin and 2.0 mM 6-DMAP for 2.0 h, which were found to be significantly(P<0.05) higher than the cleavage(45.2%) and developement to blastocyst stage(14.3%) from the oocytes activated with electrical stimulation. The significantly(P<0.05) more oocytes(71.4%) developed to 4 cell stage at 24 h post activation by ionomycin and 6-DMAP than those by electrical stimulation(18.9%). For the nuclear transplant embryos, the cleavage rate was similarly high in oocyte activation by electrical stimulation with(79.4%) or without ionomycin and 6-DMAP(70.5%). However, the embryo development to blastocyst stage was significantly(P<0.05) higher in oocyte activation by electrical stimulation with ionomycin and 6-DMAP(44.4%) than by electrical stimulation only(25.0%). The significantly(P<0.05) more nuclear transplant embryos(45.6%) developed to 4 cell stage at 18 h post activation by electrical stimulation with ionomycin and 6-DMAP than those by electrical stimulation only(10.6%). These results indicated that the supplemental oocyte activation by ionomycin and 6-DMAP with electrical stimulation enhanced and accelerated the preimplanted in vitro development of the rabbit nuclear transplant embryos.
        4,000원