It is very important to calculate natural frequency of the observatory tower correctly because it is keenly affected by wind response vibration due to its large slenderness ratio, weight and small damping ratio. Additionally, suggestion equation of natural frequency being used in the design phase has considerable difference between actual measured value thereby making it inappropriate to be used in the serviceability design of the observatory tower. Therefore, this paper conducted an ambient vibration measuring on 10 observatory towers through mobile-phone application thereby calculating the natural frequency and comparing the result with the domestic and foreign standards and that of the eigen-value analysis. This paper suggested approximate equation of the natural frequency of the observatory tower; T=0.0266H. The square of the corelation coefficient is 0.940, which is high.

The cases of conducting the vibration measurement using the mobile phone with regard to the building's horizontal vibration are very rare in Korea and foreign countries. Therefore, this study analyzed the horizontal vibration nature of the building using the mobile phone targeting 5 tall buildings, and reviewed about the applicability of the mobile phone vibration measuring instrument through the comparison/verification with the data of the existing vibration measuring instrument. The peak of the measured time series waveform was measured clearly and it showed a similar value to the existing natural frequency.

In Seoul, total 27 places of foot-bridges were chosen to evaluate the damping ratio through vibration measurement by mobile-phone application. Model vibration test was performed to compare the natural frequency and damping ratio between the conventional accelerometer and mobile-phone application. Measured average damping was compared with the one of Bachmann. The relation between the damping ratio and span was also investigated. Measured average damping ratio was greater than that of Bachmann. It was shown that there is no distinct trend between damping and span.

2두의 삼원교잡 모돈(L.×LW×D)으로부터 정상분만시켜 얻은 총 16두의 신생자돈에 Lactobacillus casei YS 생균 분말을 4주동안 경구 투여하여 얻은 성적을 요약하면 다음과 같다. 시험구의 증체량이 대조구에 비해 우수하였으며 투여후 1주일만에 하리예방 효과도 나타났다. 소장상부의 내용물당 유산균 수는 g당 시험구와 대조구모두 10^6cfu 정도로 비슷하였으나 시험구의 coliform수는 뚜렷하게 감소하였다. 분변중의 유산균 및 coliform수는 유산균 투여에도 불구하고 크게 변화하지 않으며 10^6-10^7 cfu/g 정도였다. 소화관 내용물의 pH는 소장상부에서 감소경향이 유의적으로 나타났다. 소장상부에 우세한 균종은 시험구가 L. salivarius, L. fermentum, L. casei였고 대조구는 L. salivarius, L. acidophilus 그리고 L. curvatus였다. 한편, 하리자돈으로부터 분리한 대장균은 Streptomycin, Ampicillin에는 내성을 보였고, Nalidixic acid, Gentamycin, Neomycin에는 감수성이 있었다.

폐 처리된 스토론튬(Sr) 페라이트를 사용하여 GHz 대역용 전파흡수체를 개발하였다. 도전손실재인 카본의 첨가에 따른 전파흡수능의 변화와 시편 제작시 제작온도 변화에 따른 전파흡수능의 변화를 조사하였다. 이와 같은 실험을 실시하여 스토론튬(Sr) 페라이트 : 실리콘 (slicone)고무 : 카본 (carbon)=80 : 13.6 : 6.4 wt%인 시편을 70℃에서 제작하여 두께 2mm인 시편에 대하여 9.4 GHz에서 -24 dB, 두께 3mm인 시편에 대하여 5.5 GHz에서 -23 dB인 우수한 전파흡수체를 개발하였다.