The major limiting factor of the reproductive performance on many farms is the failure to detect estrus in a timely and accurate manner. The estrus detection for Hanwoo cows (Bos taurus coreanea) is generally performed by the visual observation which is estimated at about 40% detection rate only. This recurring problem among farmers has motivated the development of various estrus detection aids. The mounting event duration threshold, standing heat event frequency threshold, estrus detection algorithm and so on, are necessarily needed in order to detect the estrus of Hanwoo cows accurately when using some automatic devices. However, they are not yet investigated for Hanwoo cows. Therefore, the objective of this study was to establish a mounting event duration threshold and standing heat event frequency threshold more specifically for Hanwoo breed by discriminating the duration of standing heat mounting from shorter duration spurious mountings which routinely occur in cattle herds. One hundred and fifty Hanwoo cows with an age between 2 to 5 years were used in this study. Cows that were expected to come into estrus within 3days were randomly assigned to each compartment for the estrus group (EG). The heated cows were video recorded for about 24 hours until after post estrus. The results showed that Hanwoo cows can be considered on estrus when it stand immobile during mounted by any other cow in more than or equal to 3.15s and 3.22s in chest-tail head mount (CTM) and head-above back mount (HBM) and that occurs consecutively at least three times within 876.4s interval. The algorithm was also developed using the thresholds of the mount duration, mount interval and consecutive occurrence number.

In present work, amorphous TiCuNi powders were fabricated by mechanical alloying process. Amorphization and crystallization behaviors of the TiCuNi powders during high-energy ball milling and subsequent microstructure changes were studied by X-ray diffraction and transmission electron microscope. TEM samples were prepared by the focused ion beam technique. The morphology of powders prepared with different milling times was observed by field-emission scanning electron microscope and optical microscope. The powders developed a fine, layered, homogeneous structure with milling times. The crystallization behavior showed that glass transition, , onset crystallization, , and super cooled liquid range were 628, 755 and 127K, respectively. The as-prepared amorphous TiCuNi powders were consolidated by spark plasma sintering process. Full densified TiCuNi samples were successfully produced by the spark plasma sintering process. Crystallization of the MA powders happened during sintering at 733K.

본 연구에서는 불과 함께 에스테르화 반응물 및 생성물 일부가 친수성 막을 투과하는 비완전 분리를 고려한 투과증발-촉진 에스테르화 반응모델을 확립하였으며, 이 모사모델에 막 분리 효율 및 물 제거능력을 설명하는 항들을 포함시킴으로써 막 투과분리가 에스테르화 반응에 어떻게 영향을 끼치는가를 공정모사를 통해서 체계적으로 살펴보았다. 모사결과 막을 통한 비완전 분리 즉, 분리막을 통한 반응물의 투과는 역반응을 유발시켜 전체 반응을 지연시키며 그 결과 반응 전 환율은 투과증발 공정을 사용하지 않은 반응보다는 높으나 물에 대한 완전한 투과선택도를 갖는 투과증발 공정을 사용하는 반응시스템보다는 낮음을 알 수가 있었다. 반응 시스템 내에서 장착된 막을 통한 투과로 인한 반응부피의 변화가 반응 속도에 끼치는 영향을 살펴보았는데 반응 초기에는 반응물 농축효과가 지배적이어서 반응을 촉진시키며, 반응이 진행되어 생성물이 형성됨에 따라 생성물 농축효과가 점점 중요해지고 이 효과가 반응의 속도를 감소시킴을 알 수가 있었다. 에스테르화 반응공정 중에 투과증발공정을 적용하는 시점에 따라 반응속도, 반응 전화율이 달라짐을 공정모사를 통해 관찰하였다. 반응 모델 식으로부터 분리막의 성능과 반응 인자들 간의 상관관계는 확립하고 이 상관관계를 주어진 막 분리능력 하에서 반응 인자 조건 설정, 혹은 주어진 반응조건 하에서 막 분리능력을 설계하는 도구로 사용할 수 있다.

We compare the results of the surveys of starless cores performed with CS (2-1) and (3-2) lines to study inward motions in the cores. The velocity shifts of the CS(3-2) and (2-1) lines with respect to N2H+ are found to correlate well with each other and to have similar number distributions, implying that, in many cores, systematic inward motions of gaseous material may occur over a range of density of at least a factor ~ 4. Fits of the CS spectra to a 2-layer radiative transfer model in ten infall candidates suggest that the median effective line-of-sight speed of the inward-moving gas is ~ 0.07 km s-l for CS (3-2) and ~ 0.04 km s-l for CS(2-1). Considering that the optical depth obtained from the fits is usually smaller in CS(3-2) than in (2-1) line, this may indicate that CS(3-2) usually traces inner, denser gas with greater inward motions than CS(2-1) implying that many of the infall candidates have faster infall toward the center. However, this conclusion may not be representative of all starless core infall candidates, due to the statistically small number analyzed here. Further line observations will be useful to test this conclusion.