• 한국환경과학회지
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• 제2권2호
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• pp.29-29
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• 1993

Shingal reservoir is a relatively small (211ha) and shallow impoundment, and approximately 25 ha of its sediment is exposed after spring drawdown. At least 14 vascular p13n1 species germinate on the exposed sediment, but Persimria vulgaris Webb et Moq. quickly dominates the vegetation. In order to estimate the role of the vegetation in the dynamics of heavy metal pollutants in the reservoir, Cu concentration of water, fallout particles, exposed sediment, and tissues of p. vulgaris, Ivas analyzed. Cu content in reservoir water decreased from $13.10mg/m^2$ on May 15 (before dralvdown) to $3.08mg/m^2$ in June 1 (after drawdown), mainly due to the loiwering of water level. Average atmospheric deposition of Cu by fallout particles was $10.84 {\mu}g/m^2/day$. Cu content in the surface 15cm of exposed sediment decreased from $5.094g1m^2$ right after drawdown, to $0.530g/m^2$ in 41 days, which is a 89.6% decrease. Therefore up to 99.7% of Cu in the reservoir appears to exist in the sediment. only 0.3% in water If the rate of atmospheric Input by fallout particles is assumed to have been the same since 1958, when the reservoir was completed, cumulative input of Cu during the 38 years would have been $150.35mg/m^2$, which is only 3.0% of Cu content in sediment right after drawdown. Therefore, most of Cu in the Shingal reservoir must have been transported by the Shingal-chun flowing into the reservoir, Standing crop of vegetation on the exposed sediment 41 days after drawdown was $730.67g/m^2$, of which 630.91g/m2 was p. vulgaris alone, and Cu content in P vulgaris at this time was $6.612mg/m^2$. This was only 0.13% of Cu in the exposed sediment, but was 50.5% of Cu in water before drawdown, or 167% of the average annual input of Cu by atmospheric deposition. If other plants were assumed to absorb Cu to the same concentration as p. vulgaris, total amount of Cu absorbed in 41 days by vegetation on the exposed sediment is estimated to be 1913.3 g, which is a considerable contribution to the purification of the reservoir water.

• Asian-Australasian Journal of Animal Sciences
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• 제19권4호
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• pp.582-586
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• 2006

This experiment was conducted to investigate the dietary effect of garlic powder (GP) and copper (Cu) on laying performances and the cholesterol content and quality characteristics of eggs during storage in laying hens. A total of one hundred and eighty, 50-wk-old, Hy-Line Brown layers were divided into 6 groups with 3 replicates per group (10 layers per replicate) and fed one of six diets containing GP 0%, GP 1%, GP 3%, GP 5%, Cu 200 ppm, or GP 3%-Cu 200 ppm for 5 wks. There were no differences in the laying performances and feed intakes bertween treatments. Eggshell strength, eggshell thickness and yolk color were also not affected by feeding of GP and Cu. With increasing dietary GP, Haugh unit was linearly increased after 2 wk of storage (p<0.05). The levels of serum total cholesterol in hens fed diets containing GP or Cu were lower than that of the control (p<0.05), but high density lipoprotein-cholesterol was not influenced by dietary GP or Cu. The content of egg yolk cholesterol from hens fed diets containing GP or Cu was significantly decreased from that of the control, except for the GP 1% group. Based on the results of this experiment, the decrease of Haugh unit during storage was alleviated by feeding of GP. The feeding of GP or Cu alone and in combination altered the cholesterol fractions in serum and reduced the content of egg yolk cholesterol in laying hens.

• 한국재료학회지
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• 제11권4호
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• pp.312-318
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• 2001

다발체 형성과 인발 공정으로 제조된 Cu-Nb 필라멘트 미세복합재료의 기계적 전기적 특성에 대하여 연구하였다. Nb의 함량이 증가함에 따라 강도는 점차 증가하였으나 연성은 Nb의 함량에 무관하였다. 293K와 75K에서의 항복강도의 비율은 Cu-Nb 미세복합재료의 Young의 계수 비율과 비슷하게 관찰되었다. 이러한 사실은 주로 장범위 방해물(athermal obstacles)들이 Cu-Nb 마세복합재료의 강도에 영향을 미친다는 것을 의미한다. 파면 조직관찰 결과는 Cu-Nb 미세복합재료는 Nb의 함량에 판관계없이 연성파괴의 특성을 나타내었으며, 부전선재 (subelematal wires)사이의 계면을 따라 발생하는 2차크랙 (secondary crack) 의 양은 Nb 함량이 증가함에 따라 증가하였다. 전기 전도도와 비저항비 (${\rho}_{293k}/{rho}_{75k}$)는 Nb 함량이 증가할수록 감소하였다. 이와 같은 Nb함량에 따른 전기전도도와 비저항비의 감소는 계면산란의 기여도가 증가하였기 때문이다.

• 열처리공학회지
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• 제14권1호
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• pp.17-21
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• 2001

The effects of Cr content above its solubility limit and thermomechanical treatment on tensile strength and electrical conductivity of Cu-Cr alloys were studied to obtain optimum Cr content exhibiting a high tensile strength without degradation of electrical conductivity. The increase in Cr content above the solubility limit increased tensile strength of Cu-Cr alloys without deterioration of the electrical conductivity. The electrical conductivity was not affected by cold rolling. The electrical conductivity of a Cu-3.5%Cr alloy subjected to cold rolling ${\rightarrow}$ aging treatment ($450^{\circ}C{\times}1hr$) ${\rightarrow}$ cold rolling was equal to that of the alloy subjected to cold rolling ${\rightarrow}$ aging treatment. However, the tensile strength of the alloy subjected to the former thermomechanical treatment was superior to that of the alloy subjected to the latter thermomechanical treatment at all the deformation degrees.

• 열처리공학회지
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• 제5권3호
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• pp.149-156
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• 1992

Transformation behavior and reversible shape memory effct of Ti-Ni-Cu alloys with various Cu content has been investigated by means of electrical resistivity measurement, differential scanning calorimetry. X-ray diffraction and strain gage sensor. The transformation sequence in Ti-Ni-Cu alloys substituted by Cu for Ni up to 5at.% occurs to $B2{\leftrightarrow}B19^{\prime}$ and it proceeds in two stages by addition of 10 at.%Cu. i.e. $B2{\leftrightarrow}B19{\leftrightarrow}B19^{\prime}$. But the content of Cu increases up to 20at.%, it has been transformed in one stage ; $B2{\leftrightarrow}B19$. The shape change of Ti-40Ni-10Cu alloy which was constrain aged in circular form bended in $B2{\leftrightarrow}B19$ transformation but it spreaded out in $B19{\leftrightarrow}B19^{\prime}$ transformation. The amount of reversible shape change (${\Delta}{\varepsilon}$) of Ti-47Ni-3Cu alloy constrain aged at $400^{\circ}C$ after solution treatment has a maximum value of about $5.6{\times}10^{-3}$, but that of cold rolled and constrain aged specimens exhibits a little value independent of Cu concentrations.

• 대한치과기공학회지
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• 제23권1호
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• pp.9-19
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• 2001

Microstructure and phase transformation of Ti-Ni-Cu alloy powders produced by using attrition milling method were studied. Mixed powders of Ti-(50-X)Ni-XCu ($X=0{\sim}20$ at%) in composition range were mechanically alloyed for maximum 20 hours by using SUS 1/4" ball in argon atmosphere. Ball to powder ratio was 50: 1 and impeller speed was 350rpm. Mechanically alloyed with attrition millimg method. powder was heat treated at the temperature up to $850^{\circ}C$ for 1 hour in the $10^{-6}$ torr vacuum. Ti-Ni-Cu alloy powders have been fabricated by attrition milling method. and then phase transformation behaviours and microstructual properties of the alloy powders were investigated to assist in improving the the high damping capacity of Ti-Ni-Cu shape memory alloy powders. The results obtained are as follows: 1. After heat treating of fully mechanically alloyed powder at $850^{\circ}C$ for 1hour. most of the B2 and B 19' phases was formed and $TiNi_3$ were coexisted. 2. The B 19' martensite were formed in Ti-Ni-Cu alloy powders whose Cu-content is less than 5a/o. where as the B19 martensite in those whose Cu-content is more than 10at%. 3. The powders of as-milled Ti-Ni-Cu alloys whose Cu-contents is less than 5at% are amorphous. whereas those of as-milled Ti-Ni-Cu alloys whose Cu-content is more than 10at% are crystalline. This means that Cu addition tends to suppress amorphization of Ti-Ni alloy powders.

• 한국토양비료학회지
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• 제31권2호
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• pp.107-113
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• 1998

퇴비, 석회, 규산 등 개량제 장기연용이 논 토양 및 현미중 중금속함량에 미치는 영향을 밝히기 위해 토양중 Cu 및 Zn의 연속침출($H_2O$, $KNO_3$, NaOH, $Na_2{^-}$, EDTA, $HNO_3$)을 수행하고 현미중 함량 및 토양의 화학성을 조사 분석한 결과는 다음과 같다. 퇴비, 석회, 규산 등을 장기연용한 토양의 Cu및 Zn에 대한 연속침출 결과 주된 형태는 각각 NaOH 침출성(유기태) 및 $HNO_3$ 침출성(황화물 및 잔류태)이였으며, 퇴비 장기연용으로 NaOH 침출성 및 EDTA 침출성(탄산염태) Cu함량은 증가하였고, 특히 Zn함량은 3요소 단용구보다 모든 형태에서 증가하였는데 상대적으로 증가폭이 적은 $KNO_3$ 침출성(치환태) Zn의 분포비율은 감소하였다. 개량제의 병용으로 $KNO_3$침출성 Zn함량 및 분포는 감소하였고 Cu는 일정한 경향이 없었다. NaOH 침출성 Cu함량은 유기물과 정의 상관을 보였고. 특히 Zn의 경우 모든 형태에서 유기물 및 치환성 K함량과 높은 정의 상관을 보였다. 토양의 O.M, CEC 및 양이온함량이 증가함에 따라 현미중 Cu함량은 감소하였으나 토양중 Cu 및 Zn의 모든 형태별함량과는 일정한 관련성이 없었다.

• 공업화학
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• 제16권6호
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• pp.737-741
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• 2005

본 연구에서는 제조한 MCM-41에 Cu의 함량에 따른 NO의 전환율을 고찰하였다. MCM-41은 실리카 원으로 colloid silica를 사용하였고, template로 cetyltrimethylammonium chloride (CTMACl)를 사용하여 수열 합성하였으며, Cu/MCM-41은 Cu(II) acetylacetonate를 사용해서 Cu의 농도를 5, 10, 20 그리고 40%로 변화시켜 제조하였다. 표면 특성은 pH, FT-IR로 분석하였고, 육방배열의 1차원 기공 구조는 XRD로 고찰하였다. $N_2/77K$ 등온흡착 특성은 BET식과 t-plot을 이용하여 확인하였으며, NO 제거 효율은 가스크로마토그래프를 이용하여 측정하였다. 실험 결과, Si-OH와 Si-O-Si의 stretching vibration peak가 관찰되었으며, (100), (110), (200) 그리고 (210)의 육방배열의 1차원 구조를 확인하였다. Cu 금속이 도입된 MCM-41은 Cu 도입량이 증가할수록 비표면적과 미세기공부피는 감소한 반면에 NO 제거 효율은 증가하였다. 결과적으로 Cu/MCM-41의 Cu의 함량이 증가함에 따라 전체 촉매작용 반응과 NO 제거율이 증가하였다.

• 한국토양비료학회지
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• 제41권3호
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• pp.199-205
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• 2008

본 연구는 제주지역 토양에서 Ni 함량이 높은 원인을 밝히고 인위적인 함량증가가 우려되는 Cu와 Zn의 함량 특성을 구명하기 위해 수행되었다. 토양시료는 Alfisols 4개통, Andisols 35개통, Endisols 9개통, Inceptisols 16개통, Ultisols 1개통에서 채취하였으며, 동일한 지점에서 모암(자갈) 시료를 채취하였다. 토양색별 Ni, Cu 및 Zn의 함량은 통계적인 유의성은 보이지 않았으나 Ni 평균함량은 $79.2mg\;kg^{-1}$으로 토양색으로 분류한 토양별 평균함량이 토양오염우려기준을 초과하였다. Cu 함량은 $40mg\;kg^{-1}$ 내외, Zn은 $108mg\;kg^{-1}$ 내외로 토양오염우려기준에 비해 낮았으며, 토양색간 함량 차이가 크지 않았다. 토양목별 Ni 함량은 Entisols에서 특이하게 높았으며, 그 외의 토양목에서는 비슷한 함량을 보였다. Cu와 Zn은 토양목과 무관하게 비슷한 경향을 나타내었다. Ni 함량이 많은 암석은 성산층, 신더어콘 및 침상장석 감람석현무암에서 높았으며, 장석현무암 및 조면질 안산암에서 낮았다. Ni은 경작지에 비해 비경작지 함량이 높았으나, Cu와 Zn 함량은 비경작지에 비해 경작지에서 높은 현상이 뚜렷하였다. Ni은 총 시료 중에서 표토/심토 비가 1보다 낮은 토양이 대부분이었으나 Cu와 Zn은 전함량의 표토/심토 비는 1보다 높은 토양이 많아 인위적인 요인에 의해 표토에 Cu가 집적되는 것으로 보인다.

• 열처리공학회지
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• 제23권1호
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• pp.10-16
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• 2010

The microstructure of Cu-Mg-P alloy sheet consisted of Cu matrix and very fine MgP precipitate, and it has been observed that the microstructure remains virtually unchanged by Ag additions up to 2%. Ag solutes were dissolved into the matrix and hardly found in the precipitates. The hardness increased with increase of the Ag content, while the conductivity slightly decreased. Strain hardening through cold rolling was found to be effective in improving the hardness, especially in high-Ag alloys. Aging treatment was conducted either before the first cold rolling or between the first and the final cold rolling, and the conductivity was significantly higher at the former case, regardless of the Ag content. Softening of Cu-Mg-P alloy sheet was remarkable above $400^{\circ}C$ and the Ag content did not show any significant effect on it.