In this paper, the fundamental attributes, phase composition of three pre-alloyed powders for diamond tools by water atomization were investigated. The density, hardness, bend strength and bending modulus of their hot pressing samples were examined. The results showed that the three pre-alloyed powders have excellent low temperature sintering characteristics. The physical and mechanical properties of the samples were found to be nearly the same as those of fine cobalt powders.
This paper described the state of art of porous metal materials, the typical manufacturing technologies and performances of sintered metal porous materials, with emphasis on the recent research achievements of CISRI in development of porous metal materials. High performance porous metal materials, such as metallic membrane, sub-micron asymmetric composite porous metal, large dimensional and structure complicated porous metal aeration cones and tube, metallic catalytic filter elements, lotus-type porous materials, etc, have been developed. Their applications in energy industry, petrochemical industry, clean coal process and other industrial fields were introduced and discussed.
Gas filtration at high temperature from industrial processes offers various advantages such as increasing process efficiency, improving heat recovery and materials resource recovery, etc. At the same time, it is an advanced environment protection technology. This paper describes a newly developed metallic filter element. The manufacturing process of sintered metallic powder and the mechanical and filtration characteristics of this filter element were investigated. In this work, the phase constituent changes of the powder during sintering were studied. The newly developed filter elements were found to have excellent corrosion resistance, good thermal resistance, high strength and high filtration efficiency.
This paper reports a part of research work on earthquake resistance consideration in regions of moderate seismicity, which is being carried out in the Department of Civil Engineering, Hong Kong University of Science & Technology. The possible seismic hazard in Hong Kong, which is located in a region of moderate seismicity, is described. A case study is presented to compare the wind and earthquake effects on Hong Kong buildings and to assess whether seismic analysis and desing is necessary for building structure. Potential problems of reinforced concrete buildings under earthquake effects in regions of moderate seismicity are discussed.
엽장, 엽폭, 엽의 크기와 엽형지수 등 소엽(leaflet) 형질의 변이와 8개 농업형질과의 관계를 구명하기 위하여 1992년도 대만에서 가을에 재배된 콩 유전자원 884 품종의 특성조사 자료를 분석하였던 바 주요 결과를 요약하면 다음과 같다. 1. 콩 유전자원들의 소엽 형질들의 변이를 보면 엽장은 4.3~14.7cm, 엽폭은 2.8~9.7cm에 분포하였으며, 엽의 크기(엽장 엽폭)는 12.1~124.6cm2 였다. 2. 엽장, 엽폭과 엽의 크기의 절대적 변이는 단일에 따른 영양생장량의 제한 때문에 크지 않았다. 또한 국제식물유전자원위원회(IBPGR)의 기준에 따른 분류시 엽의 크기가 대에 속하는 것은 없었다. 3. 엽형지수는 1.21~3.06의 변이를 보였으며 3품종은 피침형에 속하였고 나머지는 모두 난형 또는 중간형에 속하였다. 4. 엽장, 엽폭, 엽의 크기, 엽형지수의 범위와 평균은 온대품종군과 열대품종군간과 품종군내에서 차이가 있었다. 5. 엽장, 엽폭, 엽의 크기와 엽형지수는 100립중을 제외한 7개 형질과 고도로 유의한 정상관을 보였고 100립중과는 엽장, 엽의 크기 및 엽형지수와 고도로 유의한 부상관을 보였다. 6. 소엽 형질들의 농업형질과의 상관관계를 보면 소엽 형질간에 변이가 컸으며 엽장, 엽폭과 엽의 크기는 개화일수, R1 기 와 R8 기의 경장, 개체당협수와 밀접한 관계가 있었고 엽형지수는 다른 형질보다 100립중과 밀접한 관계가 있었다.