• The Journal of Engineering Geology
• /
• v.29 no.4
• /
• pp.565-578
• /
• 2019

Basic friction angles of Hwangdeung granite, Berea sandstone, Jeongsun marble, Hongcheon gneiss, Pungam shale and Eumseong sandy shale were measured by direct shear test, tilt test and pull test. Characteristics of basic friction angle and the accuracy of test methods were compared and the optimal method in measuring basic friction angle was suggested. Although basic friction angles might be measured accurately by direct shear test, the test apparatus is expensive and procedures are complicated. Tilt tests which is the suggested method for measuring basic friction angle by International Association for Rock Mechanics also provided similar basic friction angles measured by direct shear test. However, the error measured for the same rock type is higher than 7° and values by repeated measurements in one sample show different trends, such as increasing or decreasing or almost constant as measurements continued. The difference measured in one gneiss sample is higher 12°, indicating that tilt test may be not a reliable method for measuring basic friction angle. Not only pull test provided accurate and consistent results under low normal stresses, but also test apparatus is simple and inexpensive and procedure is not complicated, indicating that pull test may be the optimal method for measuring basic friction angle.

• Journal of Preventive Medicine and Public Health
• /
• v.21 no.2 s.24
• /
• pp.340-350
• /
• 1988

This study was carried out to clarify the effect of dietary calcium, casein, and suet on the accumulation of cadmium in mice. It was performed for 30 days, from April 11 to May 10 1988.90 mice were divided into 4 experimental groups and control group with 6 mice each dietary group, and measured survival rate, body weight, and weight ratio of organ to body. The contents of cadmium in liver, kidney, spleen, muscle and skin with hair, and feces were analyzed by atomic absorption spectrophotometer after sacrifice by anesthesia. After 30 days, the survival rate of control group was loot,, but 66.7% in group IV(basal diet+Cd+Ca) with single dose of $100{\mu}g$ cadmium and with free-intake of water containing 50ppm cadmium, and group V(basal diet+Cd+suet) with free-intake of water containing 50ppm cadmium. The rate of weight gain in the case of single dose of $100{\mu}g$ cadmium was highest in group IV as 42.3% and lowest in group V as 26.0%, whereas in the cases of free intake group W was highest as 24.0% and group II(basal diet+Cd) was lowest as 11.6%. The body weight, in the case of single dose of $100{\mu}g$ cadmium showed no increase until 5th day after acute poisoning. But in the case of free intake group, it showed very slight increase through all the breeding period. The weight ratio of organ to body were lowest in the liver of group II in both occasions. The most of cadmium adminstered. were excreted through feces within 2 days after single dose of $100{\mu}g$ cadmium. The contents of cadmium in each group were significantly higher than those of control group. In the liver, kidney, spleen and muscle, group II showed the highest level in both occasions of $100{\mu}g$ single dose and free intake of water containing 50ppm cadmium. In the skin with hair, group ll of the occasion with single dose of $100{\mu}g$ and group V with free intake showed the highest level. And the contents of cadmium in tissue were markedly higher in the occasion of free intake of water containing 50ppm cadmium. From the above results I would conclude that the addition of casein and calcium are effective in the inhibition of intesitnal absorption of cadmium esp. by calcium.

• Digital Contents
• /
• no.5 s.48
• /
• pp.16-17
• /
• 1997

한국정보보호센터(KISA)가 3월 14일 방화벽 시스템의 평가기준안에 대한 설명회를 개최했다. 국내 방화벽 관련 업체 관계자들이 참석한 이 설명회에서 KISA는 보안기능과 보증에 대한 요구사항을 기본 구조로 평가등급을 7단계로 분류하여 현재 시장에 유통되고 있는 방화벽에 등급을 부여하겠다는 것을 확실히 했다. 이러한 세부적인 평가기준안이 나옴에 따라 그동안 외산방화벽을 수입ㆍ공급해왔던 업체들은 이 평가기준안에 따른 보다 나은 평가등급을 받기 위한 대책마련에 고심하고 있다.