• Membrane and Water Treatment
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• 제13권2호
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• pp.97-104
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• 2022

With a small particle size, specific surface area and chemical nature, Pd/Cu-Fe nanocomposites can efficiently remove the organic compounds. In order to understand the applicability for in situ remediation of contaminated groundwater, the degradation of p-nitrophenol by Pd/Cu-Fe nanoparticles was investigated. The degradation results demonstrated that these nanoparticles could effectively degrade p-nitrophenol and near 90% of degradation efficiency was achieved by Pd/Cu-Fe nanocomposites for 120 min treatment. The efficiency of degradation increased significantly when the Pd content increased from 0.05 wt.% and 0.10 wt.% to 0.20 wt.%. Meanwhile, the removal percentage of p-nitrophenol increased from 75.4% and 81.7% to 89.2% within 120 min. Studies on the kinetics of p-nitrophenol that reacts with Pd/Cu-Fe nanocomposites implied that their behaviors followed the pseudo-first-order kinetics. Furthermore, the batch experiment data suggested that some factors, including Pd/Cu-Fe availability, temperature, pH, different ions (SO42-, PO43-, NO3-) and humic acid content in water, also have significant impacts on p-nitrophenol degradation efficiency. The recyclability of the material was evaluated. The results showed that the Pd/Cu-Fe nanoparticles have good recycle performance, and after three cycles, the removal rate of p-nitrophenol is still more than 83%.

• 자원환경지질
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• 제25권2호
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• pp.133-143
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• 1992

Ulsan granite is plotted mainly in the region of syeno-granite of the Streckeisen diagram, which consists with those of iron related granites in the area of Kimhae-Mulgum, while Chindong granites and Yucheon-Eonyang granites are plotted in the regions of granodiorite-diorite and monzo-granite, respectively. These granites show a differentiation trend of calc-alkaline magma, and their magmatic evolution from intermediate to acidic rocks is consistant with the general crystallization path of the Cretaceous granitic rocks in the Gyeongsang basin. The difference index (D.I.) is 70~90 for Ulsan granite, which lies between 35~80 of Chindong granites and 85~95 of Yucheon-Eonyang granites. These granites are distinguishable from each other by variation patterns of chemical elements. For instance, there is clear difference in content of some major and trace elements between Ulsan granite and Cu-related Chindong granites: Ulsan granite has high content of K (2.68%) and Ba (636 ppm), and low content of Ca (1.07%), Mg (0.50%) and Sr (185 ppm), whereas Chindong granites has less content of K (1.62%) and Ba (382 ppm), and higher content of Ca (3.75%), Mg (1.42%) and Sr (405 ppm). However, the content of Ulsan granite overlaps partly those of Yucheon-Eonyang granites, which are apparently dividable from Chindong granites. There is an usual trend that Cu content is high in Chindong granites of Cu province and Zn content is higher in Yucheon-Eonyang granites of Pb-Zn province. But it is unusual that Cu and Zn are higher in Ulsan granite (34 ppm, 74 ppm) than in Chindong granites (15 ppm, 22 ppm) and Yucheon-Eonyang granites (14 ppm, 43 ppm). This may be due to the reason that Ulsan granite is productive and Cu-Zn minerals are associated with iron ores. Productive Chindong granites in Haman-Gunbug area and Yuchon-Eonyang granites near ore deposits have higher content of Cu and Zn than Ulsang granite. Therefore, it is expected that chemical variation patterns of granites are applicable to distinguish mineral commodity of ore deposits (iron, copper, or lead-zinc) related with the granites in the Gyeongsasng basin.

• Journal of Animal Science and Technology
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• 제63권2호
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• pp.295-304
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• 2021

This study was aimed to investigate the Cu bioavailability, growth response, digestibility of nutrients, and blood metabolites of broiler chicks fed CuSO4 in nano or common forms. A total of 720 broiler chickens were distributed between eight treatments according to a completely randomized design. There were 8 treatments and 6 replicates in each treatment with 15 birds/replicate. The treatments were divided into common copper sulfate at the doses of 16 ppm, 40 ppm, 80 ppm, and 120 ppm (INO) and hot-melt extruded copper sulfate at the doses of 16 ppm, 40 ppm, 80 ppm, and 120 ppm (HME-Cu). The experiment was operated for 35 days in 2 phases (phase 1, d 0 to 14; and phase 2, d 15 to 35). No significant differences were shown in growth performance, feed intake, FCR, and nutrient digestibility among the treatments. The concentration of Cu in the serum was increased in the HME-Cu broilers compared with the INO broilers at phase 2. A linear increase was observed in the concentration of Cu in the liver in broilers fed INO diets, however, no significant differences were observed by the supplementation of HME-Cu levels. The linear increase was detected in the content of Cu in excreta in the INO and HME-Cu treatments by increasing the dietary Cu content. The HME-Cu treatments showed a lower Cu concentration in the excreta compared with the INO treatments. The higher bioavailability of Cu in HME form can decrease the recommended dose of Cu in broiler diets.

• 한국표면공학회지
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• 제32권6호
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• pp.695-702
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• 1999

We have explored the factors affecting the resistivity of Cu (Mg) alloy, which was prepared by sputtering. The results show that the resistivity is a function of Mg content, annealing temperature, annealing time, and Cu-alloy thickness. Addition of Mg to copper increases the resistivity through solute scattering. In addition, increasing Mg content promotes the interfacial reaction between Mg and SiO$_2$ to produce the free silicon and the generated free silicon dissolves into copper, resulting in a significant increase of resistivity. Furthermore, increasing oxidation temperature rapidly decreases the resistivity at the initial stage of oxidation and then continues to increase the resistivity to the saturation value with increasing oxidation time. The saturation value depends on the residual Mg content and the thickness of the alloy. TEM and AES analyses reveal that dense, uniform MgO grows to the limiting thickness of about $150\AA$. However, interfacial MgO does not show the limiting thickness, instead continues to grow until Mg is completely exhausted. From these facts, we proposed the maximum available Mg content needed to from the dense MgO on the surface and suppress the excessive interfacial reaction.

• 한국주조공학회지
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• 제26권6호
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• pp.249-257
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• 2006

The effects of alloying element and the condition of heat-treatment on the strength of squeeze-cast Al-3.0 wt%Si alloy were investigated. The strength of the alloy without grain refinement was increased with increase Cu content upto 3.0 wt% and rather decreased beyond that. The tensile strength of the alloy with grain refinement increased with Cu content upto 3.0 wt% and not changed beyond that. The strength of the alloy without grain refinement increased with the Mg content. The tensile strength with grain refinement increased with the Mg content upto 0.50 wt% and then decreased beyond that. The strength of the grain refined alloy increased by individual and simultaneous additions of Cu and Mg and the maximum strength was obtained with Al-3.0 wt%Si-4.5 wt%Cu-0.50 wt%Mg alloy. The optimum heat-treatment condition for this alloy was obtained.

• 마이크로전자및패키징학회지
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• 제20권3호
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• pp.53-57
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• 2013

Sn-3.0Ag-0.5Cu 무연솔더에서 Ag 함량의 감소는 기계적 충격 신뢰성 향상에 도움이 되는 반면 솔더링성을 저하시키는 것으로 알려져 있다. 본 연구에서는 저 Ag함유 무연솔더의 솔더링성 향상을 위해 In을 첨가한 Sn-1.2Ag-0.7Cu-0.4In 4원계 조성과 여기에 미량의 Mn 및 Pd을 첨가한 무연솔더 조성에 대하여 솔더 젖음성을 평가하고, 보드 레벨 BGA 패키지의 열싸이클링 및 기계적 충격 신뢰성을 평가하였다. Sn-1.2Ag-0.7Cu 조성에 0.4 wt% In을 첨가한 합금의 젖음성은 Sn-3.0Ag-0.5Cu에 근접한 수준으로 향상되었으나, 패키지의 열싸이클링 신뢰성은 Sn-3.0Ag-0.5Cu에 미치지 못하는 것으로 나타났다. Sn-1.2Ag-0.7Cu-0.4In 조성에 0.03 wt% Pd의 첨가는 솔더 젖음성 및 패키지 신뢰성을 저하시킨 반면에 0.1 wt% Mn을 첨가한 합금은 특히 기계적 충격 신뢰성이 Sn-3.0Ag-0.5Cu는 물론 Sn-1.0Ag-0.5Cu보다도 우수한 수준으로 향상되었는데, 이는 Mn 첨가가 합금의 모듈러스를 감소시킨 데에 기인하는 것으로 생각된다.

• 한국분말재료학회지
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• 제4권3호
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• pp.196-204
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• 1997

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.

• 한국표면공학회지
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• 제4권1호
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• pp.16-23
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• 1971

In this study , fluoborte solution consisting of lead fluoborate, tin fluoborate and cupric acetate was used. By addition of small amount of Cu+= ion to the solution, the Cu content of deposition layer was almost controlled less than 5%. The amount of Cu in deposition layer was almost constant without any influence of Pb++ & Sn++ in the solution, and the amount of Pb was increased by the increase of total concentration of Pb++ +Sn++ in the solution, and the amount of Pb was increased by the increase of total concentration of Pb++ +Sn++ in the solution . Agitation of plating solution & low current density result in the increase of Cu content. Analyzing of microscopic structures and etching tests of the deposited alloy, it was believed that the alloy had a lamellar structure consisting of copper rich lamellar and lead rich layer.

• 한국재료학회:학술대회논문집
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• 한국재료학회 1994년도 춘계 학술발표 강연 및 논문 개요집
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• pp.35-35
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• 1994

• 열처리공학회지
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• 제37권2호
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• pp.79-85
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• 2024

The effects of annealing heat treatment and the addition of Cu element on the shape memory effect of the NiTi-based alloy were investigated by analyzing differential scanning calorimeter results and characterizing recovery rate through 3D scanning after Vickers hardness test. Through 3D scanning of impressions after Vickers hardness test, the strain recovery rates for specimens without annealing treatment and annealed specimens at 400, 450, and 500℃ were measured as 45.96%, 46.76%, 52.37%, and 43.57%, respectively. This is because as the annealing temperature increases, both B19' and NiTi₂ phases, which can impede martensitic transformation, are incorporated within the NiTi matrix. Particularly, additional phase transformation from R-phase to B19' observed in specimens annealed at 400 and 450℃ significantly contributes to the improvement in strain recovery rates. Additionally, the results regarding the Cu element content indicate that when the total content of Ni and Cu is below 49.6 at.%, the precipitation of fine B19' and NiTi₂ phases within the matrix can greatly influence the transformation enthalpy and temperature range, resulting in relatively lower strain recovery rates in NiTi alloys with a small amount of Cu element produced in this study.