• Journal of Convergence Society for SMB
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• v.4 no.1
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• pp.55-62
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• 2014

Wireless capsule endoscopy (WCE) was one of the most influential bio-medical electronic technologies to be developed at the beginning of the century. In comparison to traditional endoscopic diagnosis, this application is characterized as non-invasive and low-risk, thereby providing surgeons with a new alternative for inspecting the entire gastrointestinal (GI) track in a much more user friendly way. Apart from regular hardware upgrades, the frontier of WCE research basically lies in the miniaturization of the capsule and in active locomotion. In order to overcome the intrinsic drawback of current commercialized WCE products, which is that locomotion is generally a function of natural peristalsis, active locomotion is proposed as a series of strategies used to effectively navigate the device into different organs and conduct therapeutic functions within targeted human tissues. Reviews of several novel designs with respect to this aspect of research will be discussed in this article.

• Resources Recycling
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• v.16 no.3 s.77
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• pp.44-49
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• 2007

In the present work, the high temperature oxygen pressure leaching behavior of chalcopyrite was studied in sulfuric acid solution. The influence of leaching time, temperature and oxygen partial pressure on leaching process were examined. Leaching rate of copper increased significantly with increasing leaching temperature. Copper recovery reached 87.1% within 2 hours at $200^{\circ}C$ and 10 atm oxygen pressure, while most of the solubilized iron readily re-precipitates as hematite($Fe_2O_3$). It was confirmed that e main leach reaction of chalcopyrite occurred through oxidation with oxygen under oxygen pressure and high temperature(above $150^{\circ}C$). Because sulfur was oxidized entirely to sulfate, passivating elemental sulfur layer was not formed.

• Journal of the Korean GEO-environmental Society
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• v.7 no.1
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• pp.29-39
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• 2006

Recently, Korea brings to remarkable levels about industrialization, modernization, population and development of technology. Especially, the rapidly growing from this technology has increased the burden on existing industrial waste landfills. The purpose of this research is to existing knowledge base of landfill cover liner behavior during periods freeze/thaw. Although these tests have been invaluable in clarifying the problem of freeze/thaw, extending the results of such experimental studies to prototype landfills are questionable. For this investigation, the author utilized a large scale laboratory simulation allowing inclusion of the field depth of the cover systems, layered soil profiles, rainfall simulation, a cold climate and boundary conditions similar to those encountered in the landfill. And the soil materials used stabilized soils (mixed clays, cements, and minerals) instead of clays. The bottom liners are made up of drainage layer (30cm), stabilized layer (75cm), and leach collection layer (60cm). The stabilized layers are made up of supporting layer (45cm) and impermeable layer (30cm) - consisted of $P_A$ and $P_B$ layer.

• Journal of the Korea Institute of Information and Communication Engineering
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• v.17 no.2
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• pp.495-502
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• 2013

In the mobile Ad hoc Network(MANET), improving technique for management and control of topology is recognized as an important part of the next generation network. In this paper, we proposed an efficient node life time management of ATICC(Adaptive Time Interval Clustering Control) in Ad-hoc Networks. Ad-hoc Network is a self-configuration network or wireless multi-hop network based on inference topology. This is a method of path routing management node for increasing the network life time through the periodical route alternation. The proposed ATICC algorithm is time interval control technique depended on the use of the battery energy while node management considering the attribute of node and network routing. This can reduce the network traffic of nodes consume energy cost effectively. As a result, it could be improving the network life time by using timing control method in ad-hoc networks.

• Resources Recycling
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• v.17 no.2
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• pp.30-35
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• 2008

Mixed acidophilic bacteria were approached for leaching of cobalt and lithium from wastes of lithium ion battery industries. The growth substrates for the mixed mesophilic bacteria are elemental sulfur and ferrous ion. Bioleaching of the metal was due to the protonic action of sulfate ion on the metals present in the waste. It was investigated that bioleaching of cobalt was faster than lithium. Bacterial action could leach out about 80 % of cobalt and 20 % of lithium from the solid wastes within 12 days of the experimental period. Higher solid/liquid ratio was found to be detrimental for bacterial growth due to the toxic nature of the metals. At high elemental sulfur concentration, the sulfur powder was observed to be in undissolved form and hence the leaching rate also decreased with increase of sulfur amount.

• Journal of the Korean Society of Environmental Restoration Technology
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• v.4 no.4
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• pp.56-63
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• 2001

This paper presents treatment efficiency and plant growth of a subsurface-flow constructed wetland system (23 m in length, 6.5 m in width, 0.65 m in depth) over one year after its establishment on floodplain of a stream in June 2000. An upper layer of 10 cm in depth was filled with course sand and the main biological layer of 50 cm depth with crushed stone with 8 - 15 mm in diameter. The system was planted with common reeds (Phragmites australis) grown on pots. Effluent discharged from a secondary-level treatment plant was funneled into it. Reed stems emerging in April 2001 grew up to 145.9cm until July 2001. The number of reed stems in July 2001 increased by about 11 times compared with that just after planting. The system was inundated seven times by storms over the monitoring period. Reeds were slightly bent after flooding, however they returned to almost upright standing in a couple of weeks. Small portion of inside slope of berm was eroded and the system surface had a sedimentation of 2 - 3 mm in depth. The average removal rates for SS, $BOD_5$, T-N and T-P was 73%, 70%, 53%, and 72%, respectively. The purification efficiencies for SS and $BOD_5$ were fairly good. The reduction rates for T-N was relatively low for the period of late fall through winter until early spring due to lower water temperature which retarded microbial nitrification and denitrification mechanisms. Reduction in the concentration of T-P during fall and winter was relatively higher than that during spring. Leach of phosphorous from plant litters lying on system surface and slight resuspension of precipitated phosphorous in substrates resulted in lower reduction for T-P in spring.

• Journal of Nuclear Fuel Cycle and Waste Technology(JNFCWT)
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• v.3 no.3
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• pp.201-211
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• 2005

In this study, conventional head-end processes of spent TRISO fuel have been reviewed to develope more effective treatment methods. The main concerns in the TRISO treatment are to effectively separate the carbon and SiC contained in the TRISO particles. The crush-burn scheme which was considered in the early stages of the development has been replaced by the crush-leach process because of $^{14}C$ problems as a second waste being generated during the process. However, there are still many obstacles to overcome in the reported processes. Hence, innovative thermomechanical concepts and a molten salt electrochemical approach to breach the coating layers of the TRISO particle with a minimized amount of second waste are proposed in this paper and their principles are described in detail.

• Resources Recycling
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• v.12 no.6
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• pp.57-63
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• 2003

In this study, the separation of neodymium was investigated from NdFeB permanent magnet scrap. Decomposition and leach-ing process of NdFeB permanent magnet scrap by oxidation roasting and sulfuric arid leaching were examined. Neodymium could be separated from iron by double salt precipitation using sodium sulfate. The optimum conditions established for decom-position and leaching are as follows: oxidation roasting temperature is $500^{\circ}C$ for sintered scrap and $700^{\circ}C$ for bonded scrap, concentration of sulfuric acid in leaching solution is 2.0 M, leaching temperature and time is $50^{\circ}C$ and 2 hrs, and pulp density is 15%. The leaching yield of neodymium and iron was 99.4% and 95.7% respectively. The optimum condition for separation of neodymium by double-salt precipitation was 2 equivalents of sodium sulfate and $50^{\circ}C$ The yield of neodymium was above 99.9%.

• Tribology and Lubricants
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• v.26 no.6
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• pp.317-321
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• 2010

Thin films of tin sulphide (SnS) have been formed by a novel 2-stage process where-in D.C. magnetron sputtering was used to deposit to thin films of tin (Sn) and the layers then sulphidised using 5% hydrogen sulphide ($H_2S$) gas in Argon. Although it was not found possible to deposit high quality thin films of tin directly onto glass substrates, excellent layers of tin were produced by using molybdenum (Mo) coated glass as the substrate material. The chemical and physical properties of the SnS layers formed were determined using scanning electron microscopy, energy dispersive x-ray analysis, x-ray diffraction studies and using reflectance versus wavelength measurements and these related to the conditions of synthesis. The data shows that it should be possible to produce conventional "substrate structure" devices based on the use of this technology.

• Ocean and Polar Research
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• v.31 no.2
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• pp.167-176
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• 2009

Cobalt-rich manganese crusts on seamounts have received an increasing amount of attention as future resources for Co, Ni, Cu, and Mn. A dearth of detailed information regarding the relevant distribution characteristics, mining technologies, and ore processing technologies, however, has precluded potential evaluations of the technical and economic advantages of these crusts. In the past 4 years, Korea has undertaken a survey of the cobalt-rich manganese crusts in and around the Magellan Seamount and Mid-Pacific Mountains. This paper introduces the preliminary feasibility study of the distribution features and R&D results centered around the development of the cobalt-rich manganese crusts. The evaluation model was developed by modifying the model for the manganese nodules. In addition to considering the geological and geophysical differences between the manganese nodules and the cobalt-rich manganese crusts, an ore dressing subsystem was installed in the model. The mining subsystem is composed of a self-propelled collector--a pipeline with submersible hydraulic pumps for crust lifting. The smelting and chlorine leach method was selected for metallurgical processing. The production scales were established at 2,500t/y of cobalt metal. The production of three metals--cobalt, nickel, and copper--was considered in terms of metallurgical processing. The economic feasibility analyses demonstrated that the payback period was 11.4 years, the NPV was 36M$, and the IRR was 9.6% with the economic factors in the case of a cobalt price of US$ 25/lb. It was also demonstrated in this study that the payback period was 8.6 years, the NPV was 154M$, and the IRR was 14.0% in the case of a cobalt price of US$ 30/lb. This indicates that the approach under consideration appears to offer greater potential given the predicted metal prices.