• Journal of fish pathology
• /
• v.25 no.2
• /
• pp.103-109
• /
• 2012

The objective of this study was to investigate the effects of exposured $Cu^{2+}$ on growth and bioaccumulation of abalone Haliotis discus hannai. Abalone were exposed to various concentration of $Cu^{2+}$ (0, 5, 10, 20, $40{\mu}g/L$). Bioaccumulation of tissues, hepatopancreas, muscles and gills were measured. hepatopancreas and gills $Cu^{2+}$ concentration of abalone increases to extent during the 4 weeks accumulation time. But muscles showed no significant changes, with respect to control. These data indicate that abalone Haliotis discus hannai hepatopancreas and gills can be considered adequate target tissues for waterborne exposured of $Cu^{2+}$. Weight growth rate of abalone exposed to $Cu^{2+}$ was significantly decreased in 20 and $40{\mu}g/L$ groups compared to control. This study revealed that high $Cu^{2+}$ concentration (${\geq}20{\mu}g/{\ell}$) reduced growth of abalone. These data indicate that excessive waterborne $Cu^{2+}$ can affect the toxicity of xenbiotics to abalone through alterations in growth rate. Thus, environmental standard of $Cu^{2+}$ $20{\mu}g/L$, should be considered a potential source of variation in toxicological studies with abalone.

• Journal of Environmental Science International
• /
• v.30 no.1
• /
• pp.57-67
• /
• 2021

Photocatalytic green energy H2 production utilizing inexhaustible solar energy has been considered as a potential solution to problems of energy scarcity and environmental contamination. However, the design of a cost-effective photocatalyst using simple synthesis methodology is still a grand challenge. Herein, a low-cost transition metal, Cu-loaded one-dimensional TiO2 nanorods (Cu/TNR) were fabricated using an easy-to-use synthesis methodology for significant H2 production under simulated solar light. X-ray photoelectron spectral studies and electron microscopy measurements provide evidence to support the successful formation of the Cu/TNR catalyst under our experimental conditions. UV-vis DRS studies further demonstrate that introducing Cu on the surface of TNR substantially increases light absorption in the visible range. Notably, the Cu/TNR catalyst with optimum Cu content, achieved a remarkable H2 production with a yield of 39,239 µmol/g after 3 h of solar light illumination, representing 7.4- and 27.7-fold enhancements against TNR and commercial P25, respectively. The notably improved H2 evolution activity of the target Cu/TNR catalyst was primarily attributed to its excellent separation and efficiently hampered recombination of photoexcited electron-hole pairs. The Cu/TNR catalyst is, therefore, a potential candidate for photocatalytic green energy applications.

• Journal of Radiopharmaceuticals and Molecular Probes
• /
• v.8 no.2
• /
• pp.139-150
• /
• 2022

Theranostics, a composite word of therapy and diagnosis, is known as personalized medicine and the concept of diagnosis and treatment at the same time. In nuclear medicine, it means performing both therapeutic and diagnostic radioisotope therapy using the same target molecule. The increased production and utilization of ⁶⁴Cu opens a new era of theranostics. The studies introduced here have shown that ⁶⁴CuCl₂ and various compounds or biomolecules labeled with ⁶⁴Cu are unique radiopharmaceuticals with physiological properties suitable for use as diagnostic and therapeutic agents. So far, these two abilities have been described only for radioactive iodine. Although ⁶⁴Cu has complex chemical properties compared to other PET radioisotopes such as ⁶⁸Ga, it has an appropriate half-life and enables high-quality PET images similar to ¹⁸F, which is an advantage in terms of diagnosis. In addition, since it also has therapeutic properties through the release of β^- particles and Auger electrons by electron capture, radiopharmaceuticals using ⁶⁴Cu stand for innovative radiopharmaceuticals for theranostic purposes. Therefore, based on the initial results obtained using ⁶⁴Cu as a therapeutic agent, it is expected that additional research on the application of ⁶⁴Cu will lead to a new era in the theranostics field.

• Journal of the Korean Applied Science and Technology
• /
• v.32 no.2
• /
• pp.232-239
• /
• 2015

In this paper, we study the dry transfer technology utilizing PDMS (Polydimethylsiloxane) stamp of a large single-layer graphene grown on Cu-foil as catalytic metal by using Chemical Vapor Deposition (CVD). By changing the surface property of the target substrate through $UV/O_3$ treatment, we can transfer the graphene on the target substrate while minimizing mechanical damages of graphene layer. Multi-layer (1~4 layers) graphene was stacked on $SiO_2/Si$ wafer successfully by repeating thetransfer method/process and then optical transmittance and sheet resistance of graphene layers have been measured as a quality assessment.

• Journal of Powder Materials
• /
• v.18 no.6
• /
• pp.552-561
• /
• 2011

This study attempted to manufacture a Cu-15 at.%Ga coating layer via the cold spray process and investigated the effect of heat treatment environment on the properties of cold sprayed coating material. Three kinds of heat treatment environments, $5%H_2$+argon, pure argon, and vacuum were used in this study. Annealing treatments were conducted at $200{\sim}800^{\circ}C$/1 hr. With the cold sprayed coating layer, pure ${\alpha}$-Cu and small amounts of $Ga_2O_3$ were detected in the XRD, EDS, EPMA analyses. Porosity significantly decreased and hardness also decreased with increasing annealing temperature. The inhomogeneous dendritic microstructure of cold sprayed coating material changed to the homogeneous and dense one (microstructural evolution) with annealing heat treatment. Oxides near the interface of particles could be reduced by heat treatment especially in vacuum and argon environments. Vacuum environment during heat treatment was suggested to be most effective one to improve the densification and purification properties of cold sprayed Cu-15 at.%Ga coating material.

• Proceedings of the Korean Institute of Surface Engineering Conference
• /
• 2001.06a
• /
• pp.13-13
• /
• 2001

현재 초고속 가공 공구의 국내 시장은 150억원이며 향후 3년 내에 1500억원으로 급성 장활 전망이다. 무윤활 초고속 가공을 실현하기 위해서는 윤활특성이 우수한 초고경도 코팅의 개발이 필요하며 이를 통해 기계설비의 수명향상과 폐유문제 해결을 기대할 수 있다. 기존의 고체윤활 코팅은 초고경도 코팅의 상부에 $MoS_2$, Graphite 등 윤활성 박막을 합성하였으나, 이들은 Hexagonal 구조의 연질 박막이며 수분이 존재하는 대기중에서는 윤활 및 내마모 특성이 급격히 저하된다. 환경친화 대체소재 개발의 일원으로 TiN, ZrN 박막 등이 이미 개발되었고 기계적 특성이 우수하여 널리 응용되고 있으나 아직 경도(약 20GPa 내외) 및 윤활성의 한계 (마찰계수 $\mu=O.6$)를 극복하지 못하고 있다. TiN박막 위의 Cu의 첨가는 TiN의 구조와 성질을 크게 변화시키는 것으로 알려져 있다. 따라서 본 연구에서는 TiN 기지 위에 Cu를 도핑함으로써 경도의 상승을 통환 내구력의 향상과 마찰계수의 감소를 통한 윤활성의 향상을 보고자하였다. TiN합성의 안정화를 위하여 magnetron sputtering과 arc ion pIatingd을 병용한 hybrid 공정을 이용하였다. Cu첨가에 따른 결정 성장 거동의 변화를 보기 위해 XRD 분석을 실행하였고, EDS 분석을 통해 Cu target 전류밀도에 의한 기지내의 Cu의 함량변화를 고찰하였으며, 경도 및 윤활특성을 고찰하기 위해서 경도 시험과 마모 시험(ball-on disc type test)를 하였다.

• 한국신재생에너지학회:학술대회논문집
• /
• 2007.11a
• /
• pp.270-273
• /
• 2007

In this report, Indium-free and Indium-reduced thin film materials for solar absorber were studied in order to search alternative materials for thin film solar cell. The films of $Cu_2ZnSnSe_4$ and $Cu_2ZnSnSe_2$ were deposited using mixed binary chalcogenides powders. From the film bulk analysis result, it is observed that Cu concentration is a function of substrate temperature as well as CuSe mole ratio in the target. Under optimized conditions, $Cu_2ZnSnSe_4$ and $Cu_2ZnSnSe_2$ thin films grow with strong (112), (220/204) and (312/116) reflections. Films are found to exhibit a high absorption coefficient of $10^4$ $cm^{-1}$. $Cu_2ZnSnSe_4$ film shows a 1.5 eV band gap. On the other side, an increasing of optical band gap from 1.0 eV to 1.25 eV ($CuInSnSe_2$) is found to be proportional with an increasing of Zn concentration. All films have a p-type semiconductor characteristic with a carrier concentration in the order of $10^{14}$ $cm^{-3}$, a mobility about $10^1$ $cm^{2{\cdot}-1.}S^{-1}$ and a resistivity at the range of $10^2-10^6$ ${\Omega}{\cdot}m$.

• Proceedings of the KIEE Conference
• /
• 2000.07c
• /
• pp.1488-1490
• /
• 2000

ZnO:Cu thin films are deposited by using an RF magnetron co-sputtering system with Cu chips attached on ZnO target. Structural and electrical properties are analyzed as a function of deposition conditions, such as Cu chip areas, $O_2/(Ar+O_2)$ ratios, and working pressures, The results show that a higher electrical resistivity above $10^{10}$ ${\Omega}cm$ along with an excellent c-axial growth can be easily achieved by Cu-doping. SAW filters based on the ZnO:Cu films are also fabricated to estimate the electric-mechanical coupling coefficient($K^{2}_{eff}$). Higher $K^{2}_{eff}$ and lower insertion losses are observed for ZnO:Cu films, compared with those for ZnO films.

• Journal of Distribution Science
• /
• v.15 no.8
• /
• pp.55-64
• /
• 2017

Purpose - PB products at convenience stores take up about 20% of all products, and strategies for differentiation from other companies and brand image building are very important. This study would investigate the strategy for differentiating PB products and successful brand building strategy, focusing on BGF Retail that is operating 'CU', the leader in the convenience store industry in Korea. Research design, data, and methodology - This study would attempt to make an exploratory approach to PB products limited to those in convenience stores. As a research subject, this study chose BGF Retail, the operator of CU, which is the leader in the convenience store industry in Korea and chose the case study method in order to examine the strategy for differentiating PB products in convenience stores more in depth. For this purpose, this study collected materials such as papers, newspaper articles and various reports on convenience store-related PB products and conducted an in-depth study including more practical contents through an interview with CU workers. Results - CU pursued the diversity of PB products and has had the diversity of products, more than 120 kinds. It founded a product research institute and has been in charge of the differentiation strategy from planning products to launching them. Changing the target layer of consumers to those in middle age of the 40s-50s, it succeeded in the strategy expanding the consumer class. In the long run, despite it changed the name of the company, it has built a successful image, and both revenue and operating profit have continuously grown up. Conclusions - In results, CU has reset the changing main target population, and the product research institute succeeded in the innovation of products, reflecting new trends the customers want. Through this study, the practical implications could be provided for competitors.

• Journal of the Korean Magnetics Society
• /
• v.18 no.1
• /
• pp.32-35
• /
• 2008

Thermally stable diffusion barrier of tungsten carbon nitride(W-C-N) and of tungsten boron carbon nitride(W-B-C-N) thin films have studied to investigate the impurity behaviors of boron and nitrogen. In this paper we newly deposited tungsten boron carbon nitride(W-B-C-N) thin film for various $W_2B$ target power on silicon substrate. The impurities of the 100nm-thick W-C-N and W-B-C-N thin films provide stuffing effect for preventing the inter-diffusion between W-C-N or W-B-C-N thin films and silicon during the high temperature($700^{\circ}C{\sim}1000^{\circ}C$) annealing process.