transition metals(Cu, Co)/ZSM-5 catalyst was made by mechanical alloying method, and their microstructures and repeated usage-properties were investigated by scanning electron microscopy, transmission electron microscopy and X-ray diffraction. The conversions ability of NO in the catalyst was measured. A part of ZSM-5 in CO/ZSM-5 composite powders was amorphous and the amorphous phase became less stable with increasing Co content. Conversion ability of NO in 10Cu/ZSM-5 powders decreased from 89% to 12% and that in 10Co/ZSM-5 decreased from 22% to 17% by 7 times conversion tests.

Joining of AIN ceramics to W and Cu by active-metal brazing method was tried with use of (Ag-Cu)-Ti alloy as insert-metal. Joints were produced under various conditions of temperature, holding time and Ti-content in (Ag-Cu) alloy Reaction and microstructural development in bonded interface were investigated through observation and analysis by SEM/EDS, EPMA and XRD. Joint strengths were measured by shear test. Bonded interface consists of two layers: an insert-metal layer of eutectic Ag- and Cu-rich phases and a reaction layer of TiN. Thickness of reaction layer increases with bonding temperature, holding time and Ti-content of insert-metal. It was confirmed that the growth of reaction layer is a diffusion-controlled process. Activation energy for this process was 260 KJ/mol which is lower than that for N diffusion in TiN. Maximum shear strength of 108 MPa and 72 MPa were obtained for AIN/W and AIN/Cu joints, respectively. Relationship between processing variables, joint strength and thickness of reaction layer was also explained.

폐광산(廢鑛山) 주변(周邊)의 토양(土壤) 및 식물체(植物體)에 존재(存在)하는 중금속(重金屬)과 그들의 토양(土壤)에서의 존재형태(存在形態)에 따른 분포(分布)를 조사(調査)하였다. 토양(土壤) 중(中) 중금속(重金屬) 함량(含量)은 Mn을 제외(除外)하고 A토양(土壤)에서 제일 많았고, Mn은 B토양(土壤)에서 함량(含量)이 제일 높았다. 존재형태(存在形態)에 따른 각 중금속(重金屬)의 함량(含量)은 각 원소별(元素別)로 차이가 있었는데, 즉 Cd와 As는 유기태(有機態), Cu와 Pb 및 Mn은 Carbonate태(態), Fe와 Zn은 잔사태(殘渣態)가 다른 형태(形態)보다 더 높게 나타났다. 참억새와 골풀은 각각 75%와 15% 정도(程度)로 서식(棲息)하고 있었으며, 이는 이들 식물(植物)들이 중금속(重金屬)에 대해 내성(耐性)을 가지고 있음을 보여주었다. 참억새와 골풀에 분포(分布)되어 있는 중금속(重金屬)은 Mn을 제외하고 줄기보다는 뿌리에 더 많이 함유(含有)되어 있었다. 참억새의 경우 Zn은 줄기와 뿌리에 비슷하게 분포(分布)하는 것으로 나타났다. 주변(周邊) 용수(用水)의 분석(分析) 결과(結果) 침출수(浸出水)에서 중금속(重金屬) 함량(含量)이 높게 나타났으며, Fe와 Mn 및 Zn이 많이 검출(檢出)되었다.

In this paper, the behaviour of cavitation erosion, influence of corrosion and corrosion control on slide bearing metals for internal combustion engine were investigated, and this experiment was done by the vibratory cavitation erosion tester. The main results obtained are as follows: 1. With decreasing the space between horn and specimen, the weight loss and its rate increased step by step. But the weight loss and its rate of 0.2mm space decreased conversely more than that of 0.4mm space at early stage. 2. The weight loss and its rate with change of pH were appeared to the order of pH2>pH12>pH7>pH4. And the weight loss and its rate at pH 4 decreased at best. 3. The weight loss and its rate by cavitation erosion for bearing metals were shown to the order of W.M7>W.M1>K.M4. 4. There appeared mainly small pit hole at pH2, and appeared the pit of netting thread type at pH12 by the results of the damaged surfaces at pH2 and pH12 environments that were sensitive to cavitation erosion. 5. With increasing the viscosity of lubricating oil, the weight loss rate by cavitation erosion became dull at the space below 0.5mm. 6. The protective efficiency of cavitation erosion-corrosion is superior inhibitor of chormate(25 ppm) to cathodic protection.

This paper reports on the investigation of the distributions of sediments and heavy metals in Sooyoung River and its mouth, carried out during the period from July 1990 and August 1991. Since the samples were saline, water analysis was performed by the method of alkaline KMnO₄ and sediment analysis by acidic KMnO₄. Mercury was digested with both nitric and sulfuric acids, and then determined by dithizone CCl4 method. Cadmium, Zinc, Copper, Lead and Chronium were determined by atomic absorption spectroscopy after aliquots of samples were digested with nitric acid and hydrogen peroxide. Mineral components of sediments were identified by XRD and microscopic analysis. The result are as follows : 1. The ranges of COD of water and sediments were 10.6-54.6ppm and 63-26000ppm respectively. 2. The ranges of concentrations of Cadmium, Lead, Copper and Zinc for water were 0.002 -0.024ppm, 0. 013-0.060ppm, 0.013-0.736ppm, 0.003-0.012ppm, respectively. 3. The ranges of concentration of Mercury, Cadmium, Lead, Copper, Zinc and Chromium for sediments were N.D - 0.09ppm, 0 .1-2.07ppm, 0.32-5 2.35 ppm, 1.04 - 20.67 ppm, 7.1-52.50 ppm and 0.23-5.22 ppm, respectively. 4. The mineral components of the sediments were mainly quartz and feldspar.

Experiments of quenching were made with cylindrical specimens of carbon steel S45C of diameters from 12 to 30mm were performed. The specimens were heated by electric furnace and quenched by immersion method. In order to analyze the temperature profile(cooling curves) of carbon steel including the latent heat of phase transformation, nonlinear heat conduction problem was calculated by the numerical method of inverse heat conduction problem using the apparent heat capacity method. The difference between the calculated and the experimented cooling curves was caused by the latent heat of phase transformation, and the effects of the latent heat were especially manifest at the cooling curves of center of specimens. The temperature and the quantity of the latent heat of phase transformation depend on the cooling speed at A sub(1) transformation point, and the region for cooling speed to become zero was caused by the latent heat of phase transformation.

젓갈류 및 젓갈류외 원료(原料)가 되는 어패류(魚貝類), 식염중의 중금속(重金屬) 함량(含量)과 젓갈류의 중금속(重金屬) 함유요인(含有要因)에 대하여 조사(調査)한 결과(結果)는 다음과 같았다. 젓갈류중(中) 중금속(重金屬)의 평균함량(平均含量)은 Hg 0.076ppm, Pb 0.677ppm, Cd 0.112ppm, As 1.025ppm, Cu 3.540ppm, Zn 11.23ppm, Mn 2.041ppm이었으며 어패류(魚貝類)는 Hg 0.051ppm, Pb 0.425ppm, Cd 0.071ppm, As 0.632ppm, Cu 2.516ppm, Zn 8.052ppm, Mn 1.178ppm으로서 어패류(魚貝類)가 젓갈류에 비(比)해 낮은 함량(含量)이었다. 식염중의 중금속(重金屬) 함량(含量)은 Hg ND, Pb 0.05ppm, Cd 0.01ppm, As 0.02ppm, Cu 0.087ppm, Zn 0.068ppm으로 매우 낮은 함량(含量)이었다. 용기(容器)에 따른 멸치젓의 숙성시험(熟成試驗) 결과(結果) Hg, Cd는 대조구(對照區)와 차이(差異)를 보이지 않았으나 Pb는 옹기 및 철제용기(鐵製容器), As는 철제용기(鐵製容器) 및 재생(再生)플라스틱 용기(容器)에서 높은 함량(含量)을 보였다. 철제용기(鐵製容器)에서 멸치젓을 숙성(熟成)시킨 결과(結果) Hg, Cd를 제외한 다른 중금속(重金屬)은 함량(含量)이 증가(增加)하였으며, 숙성초기(熟成初期)에 비(比)해 후기(後期)에서 그 증가폭(增加幅)이 크게 나타났다. 용기(容器) 용출시험(溶出試驗) 결과(結果) Hg, Cd는 모든 용기(容器)에서 검출(檢出)되지 않았으나 그 외 중금속(重金屬)은 용출시간(溶出時試)에 따라 증가(增加)하였으며, 식염농도에 따른 중금속(重金屬) 용출(溶出)은 차이(差異)가 없었다.