• Korean Journal of Veterinary Research
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• v.30 no.1
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• pp.59-64
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• 1990

The present study was conducted in order to elucidate the asymptomatic carrier state of dermatophytes on the laboratory rodents in Korea during the period from August 1986 to April 1987. A total of 988 laboratory rodents, comprising 393 albino rats, 285 albino mice, 238 guinea pigs and 72 hamsters, were randomly selected for the isolation of dermatophytes from 6 research institutes and 2 breeding farms. And the mating experiments were performed to identified the perfect states of Trichophyton mextagrophytes isolated from albino rats. Dermatophytes were recovered from 94 of 393(23.9%) albino rats and from 3 of 5 colonies. Isolation rate of each colony was 38.4%, 32.0% and 9.8%, respectively, and the albino rats over 2 months old(28.2%) were higher than below 2 months old(2.9%) in the isolation rate of dermatophytes. Among 94 strains of dermatophytes isolated from albino rats, all the strains were identified T mentagrophytes, except 1 strain of Microsporum gypseum, and its perfect states were Arthroderma $vanbreuseghemii^+$.

• Asian-Australasian Journal of Animal Sciences
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• v.16 no.11
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• pp.1599-1603
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• 2003

The physical feature, physiological character and behavior studies were conducted with fifteen newly collected gayals in Bandarban hill tract area of Bangladesh. Their morphology is different from domestic cattle. The range of pulse rate, body temperature and respiration rate were 47 to 75 per minute, 37.78 to $38.88^{\circ}C$ and 20 to 40 per minute, respectively. These physiological values vary with different age group and seasonal variation. In hematological feature, the average findings were RBC $7.01{\pm}0.52$ million/cu.mm, WBC $14.3{\pm}3.69$ thousand/cu.mm, hemoglobin concentration $9.81{\pm}2.25gm%$, PCV $35.86{\pm}3.68%$. In differential WBC count neutrophils $28.23{\pm}1.75%$, lymphocytes $62{\pm}2.05%$, monocytes $4.4{\pm}1.34%$, eosinophils $5{\pm}2.49%$ and basophils $0.4{\pm}0.51%$. In behavior study, the animal shows browsing nature on hill slopes. They are watchful in new environment, become excited and nervous with strangers. Heated female gayals response for mating with domestic bull.

• Transactions of the Korean Society of Mechanical Engineers
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• v.12 no.3
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• pp.489-496
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• 1988

This paper is studied to know wear mechanism in variation of austempering temperature and holding time of austempered ductile cast iron against mating material SM45C hardened by heat treatment. The wear tests were carried out by rubbing the annular surface of two test pieces in dry sliding friction. The wear mechanism was investigated by scanning electron microscopy and the retained austenite volume fraction was investigated by X-ray diffractometer. The experimental results show that the wear characteristics depend largely on the oxidation of the testing materials which is influenced by the sliding velocity and distance. The retained austenite has a negative effect during frictional contact because it has increased severe wear by softened surface layer. It is shown experimentally that hard metals have lower frictional resistance and hence the resistance to adhesion is increased due to stronger interatomic linking bonds and increase in the surface energy.

• Asian-Australasian Journal of Animal Sciences
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• v.17 no.4
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• pp.569-582
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• 2004

Current growth in the deer industry is 20% per annum as the demand increases for venison in Europe, including the increased use in Asia of antlers as a natural medicine by humans. The deer industry in Australia has developed rapidly, but farm profitability has fluctuated markedly. The knowledge on deer farming has largely been adopted from New Zealand (NZ) and the United Kingdom (UK) although the environmental conditions in these deer growing countries differ markedly from Australia. The practice used for weaning is one of the key factors influencing the profitability of the industry. However, a wide range in weaning dates are practised by farmers leading to the question of whether deer should be weaned after mating to reduce the stress during weaning or should they be weaned in the pre-rut period to allow does to recover their body condition for the next reproduction cycle. This review examines the effect of weaning time on the performance of does and hinds and the subsequent growth rate of the fawns and calves. Gaps in knowledge of weaning procedures and nutritional management for early weaned deer are identified.

• Journal of Embryo Transfer
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• v.25 no.4
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• pp.215-219
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• 2010

The objective of this study was to examine the reproductive characteristics of cloned miniature piglets produced from surrogate domestic pigs. Somatic cell nuclear transfer (SCNT) miniature pig embryos were transferred into domestic pigs. As controls, domestic pigs of the same breed with surrogates for SCNT embryos and miniature pigs of the same breed with the somatic cell donor were bred by artificial insemination and natural mating, respectively. Surrogate domestic pigs that farrowed cloned miniature piglets had a significantly longer gestation length (118.1 days) than conventionally bred domestic (115.4 days) and miniature (115.5 days) pigs. Furthermore, the birth weight of cloned miniature piglets produced from domestic pigs (743 g) was significantly greater than that of miniature piglets produced by natural breeding (623 g). Also, cloned miniature piglets had a significantly lower weaning rate (49.7%) than conventionally produced domestic (91.5%) and miniature (100%) piglets. No differences were observed between female and male cloned piglets in gestation length, litter size, birth weight, or weaning rate. Our results demonstrate that gestation length is extended in domestic pigs that are transferred with SCNT miniature pig embryos and that cloned miniature piglets have increased birth weight and high pre-weaning mortality.

• Transactions of the Korean Society of Mechanical Engineers
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• v.17 no.6
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• pp.1404-1411
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• 1993

This study was undertaken to investigate the corrosive wear charateristics upon various transformation condition of austempered low-alloy ductile cast iron in corrosive environments against mating specimen made of the hardened SM45C. The corrosive wear test was carried out by rubbing the annular surface of two test pieces in distilled water and aqueous solution at constant sliding speed of 0.5m/s. In severe wear region, the corrosive wear rate Wc increased hastily with NaCl concentration owing to intermetallic adhesion but Wc went down slowly in mild wear region due to lubricating effect of the corrosion product. The critical sliding distance decreased with increasing NaCl concentration due to increased generation rate of the corrosion product and the specific corrosive wear rate has maximum in 1% NaCl aqueous solution at mild wear region. With the variation of matrix, the corrosive wear resistance of the fine acicular bainite was higher than that of coarse upper bainite because of reducing the local cell reaction by carbides. A growth in volume fraction of retained austenite in matrix increased the Wc due to soften surface, but has a declining tendency of Wc in mild wear region.

• Development and Reproduction
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• v.1 no.1
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• pp.67-77
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• 1997

Mammalian ovary consists of various growing stages of follicles. Ovarian follicular growth and differentiation, however, can be distinguished into recruitment, growth, selectiona nd ovulation. while only minute of the selected follicles ovulate their oocytes, all the rest follicles disappear by atresia. this atresia is an important event of which physiological mechanism must be resolved. The present study was carried out to investigate the effects of various doses of pregnant mare's serum gonadotropin (PMSG) on the oocyte quality, ovulation rate, and the early embryonic development in immature mice. Immature mice were administrated with 5, 20, or 40 IU PMSG. At every 12 hour up to 72 hour after treatment, body and ovary weights were measured. Oocytes were flushed from the oviducts under the dissecting microscope and observed under the inverted microscope. Late 2-cell embryos were collected from the mice which were superovulated by the same dosage of PMSG followed by 5 IU hCG 47 hours after PMSG-treatment. The percentage of abnormal oocytes was higher in 20 or 40 IU PMSG-treated animals than 5 IU PMSG-treated ones. Ovulation occured at 12 hours afger PMSG injection in all experimental groups. The percentage of retrieved abnormal oocytes increased in the 20 or 40 IU PMSG-treated goups but not in 5 IU PMSG-treated group. There was no significant difference in the mating rate among the groups [52.6% (10/19), 66.7% (10/15), 44.0% (11/25) : 5, 20, 40 IU group respectively] ; however, ther was a significant (p<0.01) increase of embryo retrieval rates in 5 and 20 IU-treated groups compared with that in 40 IU-treated group [89.2% (239-268), 85.5% (224/262), 40.0% (18/45)]. There was significant (p<0.01) increase of embryo development rates in 5 IU-treated group compared with that in 20 and 40 IU-treated group [231/239(96.7), 179/224(79.9), 77.8(14/18)]. In conclusion, higher doses of PMSG injection increased the occurrence of abnormal oocytes ovulation in immature mice. The most of oocytes collected from 5 or 20 IU-PMSG-treated group has fertilizabioity. But in mice injected iwth higher doses of PMSG, their oocytes exhibit less fertilizability and, even fertilized, all oocytes are not fully capable of development.

• Tribology and Lubricants
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• v.32 no.5
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• pp.154-159
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• 2016

This paper presents an experimental study of the leakage performance and endurance performance of a mechanical face seal in the 7-ton-class turbopump of the Korea Space Launch Vehicle 2 third-stage engine. We install a mechanical face seal between the fuel pump and turbine to prevent the mixing of the fuel and turbine gas. We design and manufacture a prototype mechanical face seal, which has two parts, namely, a bellows seal assembly and mating ring. We set up a test facility to measure the leakage and endurance of the mechanical face seal. For the similarity tests, we use water under real operating conditions such as high rotational speed, high temperature, and high pressure. Through investigation of the leakage and carbon wear rate, it is possible to evaluate the performance of the mechanical face seal. The results of the leakage and endurance performance test demonstrate the absence of any leakage from the prototype mechanical face seal after a trial run and clarify that the acceptable wear rate fully satisfies the turbopump requirements. Finally, we install a qualified mechanical face seal in a 7-ton-class turbopump and perform a validation test in the turbopump real-propellant test facility in the Korea Aerospace Research Institute. The test results confirm that the mechanical face seal works well under real operating conditions.

• Korean Journal of Environment and Ecology
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• v.22 no.1
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• pp.59-65
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• 2008

This study is mainly focused on the mating of 9 couples of Eagle Owl Bubo bubo habitating in Paju, Ganghwa Island, Icheon, Sihwa Lake, Chungju. For this study, from 2005 to 2007, regular filming and mornitoring for the breeding ecology and copulation behavior of 9 couples of Eagle Owl in the nest and near area had been done. Clutches ranged in size from one to four eggs but averaged 2.27 eggs(n=15), hatching success rate was 71 %(n=34) and fledgling success rate was 83%(n=23). Through the filming and mornitoring, it was found that Eagle Owl continued to copulate each other even after hatching and kept its copulation until the chicks left their nest($7\sim8$ weeks after hatching). This copulation behaviour without fertilization seems to be done for confirming, maintaining and strengthening of pair-bond by the necessity of both male and female, and to aim at stable breeding of their chicks.

• Asian-Australasian Journal of Animal Sciences
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• v.18 no.4
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• pp.470-474
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• 2005

The efficiency of a short-term treatment with an intravaginal device containing progesterone (CIDR) combined with pregnant mares' serum gonadotrophin (PMSG) and prostaglandin analogue ($PGF_{2\alpha}$) was evaluated for the induction of estrus, initiation of cyclic activity, and fertility in postpartum suckled yak cows. Seventy-five postpartum suckled yak cows were assigned to three treatments: (1) insertion of a CIDR intravaginal progesterone (1.9 g) (day 0), an administration of $PGF_{2\alpha}$ (0.2 mg i.m.) on day 6 and PMSG (1,000 IU i.m.) at the time of CIDR withdrawal on day 7 (CPP group, n=28); (2) an administration of $PGF_{2\alpha}$ (0.2 mg i.m.) on day 6 and PMSG (1,000 IU i.m.) on day 7 (PP group, n=21); (3) untreated animals served as the control (CG group, n=26). Seven yak bulls were placed in pastures with the cows for natural mating. Estrus rate in the CPP group (28/28) was higher (p<0.01) than in the PP group (6/21) and in the CG group (0/26) within 96 h after the end of treatment. The first service conception rate in the CPP group (21/28) was higher (p<0.01) compared with in the PP group (2/9) as judged by serum $P_4$ concentration $\geq$2.35 ng/ml on day 21 after breeding. It is concluded that a short-term progesterone treatment combined with PMSG and prostaglandin increased the proportion of yak cows that exhibited behavioral estrus with more synchronized estrus response and satisfactory conception rate in postpartum suckled yak cows.