• Asian-Australasian Journal of Animal Sciences
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• 제12권3호
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• pp.348-353
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• 1999

Ten Australian Stock Horses colts (five yearling and five 3-year old colts) of which 2 yearlings and 2 three year old colts served as control animals while 3 yearlings and 3 three year old colts received two GnRH immunizations within 4 weeks interval were used in this study. By the 5th to 6th week after immunization, the GnRH antibody titres in the plasma rose above 1:1000 and attained peak levels of 1:6500 by the 8th week and gradually declined to about 1:3000 by the 10th week in both the age groups. The testosterone and androstenedione concentrations of the control colts in both age groups were significantly greater (p<0.05) than that of the vaccinated groups. During the immunosuppression period, the vaccinated colts behaved like geldings. Semen could not be collected from 2 of the 3 three-year old vaccinated colts. The testicular dimensions, testicular weight, parenchymal weight, seminiferous tubule volumes, interstitial space volumes, Leydig cell volume, seminiferous tubule % of the control colts were significantly greater than those of the vaccinated colts in both the age groups. The 3-year old control colts had a significantly (p<0.05) greater % of Leydig cells than the control and vaccinated 1-year old colts. There was arrest of spermatogenesis with complete absence of sperm in the testes of the vaccinated colts while there was various stages of spermatogenesis in those of the control colts. Morphometric analysis demonstrated that the 3-year old colts had significantly (p<0.05) greater DSP/gm of testis and DSP/testis than those of the 1-year old control colts. This study elucidated that the GnRH immunization could suppress the testicular function of the 3-year old and yearling colts.

• 한국초지조사료학회지
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• 제29권4호
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• pp.365-374
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• 2009

본 연구는 2007년 6월 23일부터 6월 29일까지 제주도에 위치한 말 목장의 방목지에서 말의 연령에 따른 군별 행동양식을 알아보고자 실시하였다. 공시마는 육성마군 3세 11두, 육성마군 1세 12두를 대상으로 행동을 조사하였다. 연령에 따른 행동의 차이가 약간 나타나 육성마(1세) 군에서는 채식이 56%, 기립 23%, 횡와 10%, 보행 5%, 러닝 2.5%, 음수가 3%였다. 육성마 1세의 3두의 개체별 행동발현은 개체차이가 나타났으며 비율의 평균은 채식이 53%, 기립이 29%, 횡와 11%, 보행 5%, 음수 1%, 러닝 1%를 나타내었다. 육성마(3세) 군에서는 채식 54%, 기립 27%, 보행 13%, 러닝과 음수가 1.5%, 횡와가 1% 였다. 육성마 3세의 개체별 발현 비율 평균은 채식이 53%, 기립 32%, 보행 10%, running과 음수행동이 각각 1%였다. 본 연구는 우리나라에서 생산되는 경주마의 방목행동에 관한 최초의 연구라고 생각된다. 이 자료가 충분할 수는 없으나 이를 기반으로 경주마를 생산, 육성할 때 사양관리에 도움이 되고 앞으로 연구의 기초자료가 될 수 있을 것이라 사료된다.

• 대한전자공학회논문지
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• 제13권6호
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• pp.7-11
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• 1976

연산증폭기를 이용한 전압안정부저항회로를 제안하였으며, 전입력전압범위에 걸쳐서 회로를 해석하였다. 부저항영역에서 이 v-i특성이 2가지 구분된 요인에 의해서 이루어짐을 밝혔고, 이 개념에 의해서 역 v-i특성의 꼭지점을 해석하였다. 제안된 회로를 실험하여 얻은 입력 v-i특성의 직선성은 대단히 양호하였으며, 이들의 부저항치는 전압범위 ±1∼±5V에서 -86∼833Ω였다. 그리고 전입력전압범위에서 v-i특성을 검토했다. A voltage-stable negative resistance circuit with operational amplifier is proposed, and circuit analysis is given all the input voltage range. The behavior of the v-i characteristics in the nogative resistance region is devided into two causes, and top points in the input v-i characteristics of the circuit is analyzed with them. Experimental results of the v-i characteristics of the proposed circuit has a good linearity in the negative region with negative resistance, -86Ω∼-833Ω for the input voltage, ± 1∼± 5 colts. The v-i characteristics of the circuit in all the input voltage range is discussed.

• 한국정밀공학회지
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• 제18권1호
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• pp.154-161
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• 2001

A UBET analysis has been carried out to predict the forming load and the extruded length of forward and backward extrusion of hexagonal and trochoidal wrench colts. For the upper bound load and the average length of the extruded billets are determined by minimizing the total energy consumption rate which is a function of unknown velocities and parameters at each element. Experiments are carried out with antimony-lead billets at room temperature using hexagonal and trochoidal shaped punches. The theoretical predictions of the forming load and the extruded length are in good agreement with the experimetal results.

• 한국수정란이식학회지
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• 제28권3호
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• pp.223-227
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• 2013

The objective of the study is to assess temperament of a horse based on general temperament test by a questionnaire survey. Five test criteria were identified: gentleness, patience, aggressiveness, sensitivity, and friendliness, each on a 5-point scale. 114 horses bred at the National Institute of Animal Science (NIAS) in 2010, 2011 and 2012. The horses recorded scores of 3.6~3.9 for gentleness, 3.1~3.6 for patience, 3.4~4.0 for aggressiveness, 2.8~3.2 for sensitivity, and 3.4~3.8 for friendliness, the overall score for sensitivity the lowest. Horses born in 2012 scored lower than the rest in all five areas at a statistically significant level (P<0.05). By gender, the colts scored higher than the fillies in all five areas, but the discrepancy was not statistically significant. Factor analysis yielded only one factor, and the Cronbach's ${\alpha}$ value was 0.980 for standardization of Factor 1, indicating a high reliability of internal consistency. The correlation coefficients among the test criteria ranged between 0.85 and 0.91 (P<0.01). The assessment criteria used in this study are expected to provide a useful basis designing a temperament test horses.

• Journal of Korean Society for Atmospheric Environment
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• 제17권E3호
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• pp.91-99
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• 2001

Plasma reactor was used to generate a high potential difference between two surfaces of concentric pyrex tubes by electrical current. The annular gap of the reactor was calculated by trial and error from the breakdown voltage equation and set at 0.45 cm. The overall objective of this research was to know the effects of the frequency, humidity, and residence time on the formation of nitrogen oxides in a plasma reactor. The primary voltage varied from 50 to 90 volts and the frequency was varied in increments of 10 Hz from 60 to 650 Hz at the primary voltage of 90. The increase in the secondary voltage was not linear but exponential at high frequencies. At a maximum concentration of about 745 ppm, the frequency and secondary voltage was 600 Hz and 4,200 volts, respectively. All tests for the effects of humidity on NO$_{x}$ production were performed at the optimal setting of 90 colts and 600 Hz frequency. Since the NO$_{x}$ production was not an one dimensional phenomenon, competing reactions were assumed to occur in the discharge chamber. The sharp peak concentration of 1,810 ppm was observed at 38% of relative humidity, The enhanced production was choked off, and the production rate rapidly dropped to 3 ppm at above 40% of relative humidity. It is assumed that the corona attacks the most vulnerable molecules in the reaction chamber before attacking other more lightly bonded molecules, possibly at humidities above 38% and the optimized 90 volt setting. Thus, there was not enough energy left after attacking all water molecules to decompose an appreciable amount of $N_2$. If nitrogen breakdown does not occur, then oxides of nitrogen are not likely to be produced.ced.