• Proceedings of the IEEK Conference
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• 2001.10a
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• pp.448-452
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• 2001

An Experimental study was carried out to develop a simple method of processing copper waste sludge which is produced by PBC manufacturing. The procedure is based on leaching of wet sludge in 2N H$_2$SO$_4$, and the solid / liquid ratio is controlled approximately at 1/10. The recovery of copper is 85.4%, and pH of the leachate is 3.20. Adding ammonia solution into leachate forms ammine, and hydroxide compounds derived from other impurities in leachate at pH 10. The hydroxide compound can be treated by ferrite process, and the product is a stable oxide compound. Then the ammine solution is heated to evaporate ammonia, and the copper hydroxide is formed. Heating at 8$0^{\circ}C$by aeration, copper hydroxide is transformed into copper oxide with a purity of 98.4%. This process can recover most copper from sludge and the residue can be stabilized by the formation of a stable oxide compound which is not hazardous to environment.

• Proceedings of the KIEE Conference
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• 2007.04a
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• pp.433-435
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• 2007

Geographic wireless sensor networks use position information for Greedy routing. Greedy routing works well in dense network where as in sparse network it may fail and require the use of recovery algorithms. Recovery algorithms help the packet to get out of the communication void. However, these algorithms are generally costlier for resource constrained position based wireless sensor type networks. In the present work, we propose a Void Avoidance Algorithm (VAA); a novel idea based on virtual distance upgrading that allows wireless sensor nodes to remove all stuck nodes by transforming the routing graph and forward packet using greedy routing only without recovery algorithm. In VAA, the stuck node upgrades distance unless it finds next hop node which is closer to the destination than itself. VAA guarantees the packet delivery if there is a topologically valid path exists. NS-2 is used to evaluate the performance and correctness of VAA and compared the performance with GPSR. Simulation results show that our proposed algorithm achieves higher delivery ratio, lower energy consumption and efficient path.

• Proceedings of the IEEK Conference
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• 2001.10a
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• pp.719-724
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• 2001

The objective of this investigation was to separate silicon and silica for recycling by the liquid-liquid separation technique. In the preparation of silicon (Si) single crystal, a small amount of silicon is fixed on the surface of silica (quartz, $SiO_2$) crucible. The used crucible is crushed for recycling both silicon and silica in a high purity from the mixed powder. Zeta-potential of silicon and silica are almost the same at pH higher than 3. Their separation by simple flotation is ruled out. However, their hydrophobic characteristics are different in several different organic solvent from the measurement of contact angle. Therefore, the liquid-liquid extraction is employed to separate silicon and silica. The result indicates that the organic solvent mixed with dodecyl ammonium acetate could extracted the silicon powder at high purity (97-100%) with high recovery from the silica powder in the water phase.

• The Korean Journal of Pesticide Science
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• v.18 no.4
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• pp.321-329
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• 2014

This experiment was conducted to establish an analytical method for residues of amisulbrom, as recently developed an oomycete-specific fungicide showing inhibition of fungal respiration, in crops using HPLC-UVD/MS. Amisulbrom residue was extracted with acetonitrile from representative samples of five raw products which comprised apple, green pepper, kimchi cabbage, potato and hulled rice. The extract was diluted with 50 mL of saline water and directly partitioned into dichloromethane to remove polar co-extractives in the aqueous phase. For the hulled rice sample, n-hexane/acetonitrile partition was additionally employed to remove non-polar lipids. The extract was finally purified by optimized Florisil column chromatography. On an octadecylsilyl column in HPLC, amisulbrom was successfully separated from sample co-extractives and sensitively quantitated by ultraviolet absorption at 255 nm with no interference. Accuracy and precision of the proposed method was validated by the recovery test on every crop samples fortified with amisulbrom at 3 concentration levels per crop in each triplication. Mean recoveries ranged from 85.3% to 105.6% in five representative agricultural commodities. The coefficients of variation were all less than 10%, irrespective of sample types and fortification levels. Limit of quantitation (LOQ) of amisulbrom was 0.04 mg/kg as verified by the recovery experiment. A confirmatory method using LC/MS with selected-ion monitoring technique was also provided to clearly identify the suspected residue. The proposed method was sensitive, reproducible and easy-to-operate enough to routinely determine the residue of amisulbrom in agricultural commodities.

• Korean System Dynamics Review
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• v.5 no.2
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• pp.89-123
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• 2004

Using materials recovered from the waste stream instead of virgin resources as a raw material in manufacturing has great environmental and economic benefits. However, there is lack of public interest in needs for integrated waste management and its relevant facilities, because of NIMBY syndrome, This article has proposed a system dynamics model for the study of the potential and systemic consequences of resource circulation management system(RCMS) policy for a Sudokwon landfill site in Korea. The results of the study indicate that the effects of RCMS are seen continuously to increase in term with both the community welfare level and the resource and energy level. Moreover the effects of RCMS appear sharply in the first half of the simulation period.

• Journal of the Korea Institute of Military Science and Technology
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• v.9 no.3
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• pp.123-131
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• 2006

This paper reports the apparatus and method for the safe treatment of pentachlorophenol(PCP)-treated ammunition box by solvent extraction. Experimental variables were chosen as the composition of solvents, types of substance(chips and sawdust), temperatures and sonication to obtain maximum PCP removal from wood samples of the dismantled ammunition box. Up to 99% of PCP in the wood chip was extracted within 2 hours at room temperature when using methanol as the solvent. The extraction volume ratio of methanol per dried sample was about 10. Type of samples, extraction temperature and sonification showed little effects on PCP extraction. Based on this study, a resource recycling system for the treatment of ammunition boxes was recommended.

• Journal of Korea Society of Digital Industry and Information Management
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• v.9 no.1
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• pp.1-7
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• 2013

The cloud computing is technology which gives flexible and solid infrastructure to IT environment. With this technology multiple computing environment can be consolidated in to a single server so that maximize system resource utilization. Better processing power can be achieved with less system resource. IT manager can cope with increasing unnecessary cost for additional server and management cost as well. This means a enterprise is able to provide services with better quality and create new services with surplus resource. The time required for recovery from system failure will be reduced from days to minutes. Enhanced availability and continuity of enterprise business minimize the codt and the risk produced by service discontinuity. In this paper, we propose framework architecture that is strong against denial-of-service attack.

• Korean Journal of Veterinary Service
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• v.36 no.2
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• pp.127-132
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• 2013

An 11-year-old poodle bitch was presented for investigation of multicentric mammary masses. Abdominal sonography and radiography demonstrated abnormal enlargement of uterus and ovaries. Blood analysis revealed high progesterone concentration. The ovariohysterectomy and mastectomy were performed. Histopathologically, the mammary masses revealed complex carcinoma-tubulopapillary carcinoma with papillary pattern and tubule pattern. In the uterus, cystic endometrial hyperplasia was observed. Scattered inflammatory cells were observed in the endometrial stroma and mucinous material was protruded from endometrial surface. Also, in the ovaries, bilateral ovary granulosa cell tumor was detected. The bitch made a complete recovery following the ovariohysterectomy and mastectomy. This case was a very rare multiple tumor occurrence with bilateral ovary granulosa cell tumor and mammary complex carcinoma. High progesterone concentration was characterized clinically in the bitch.

• Membrane Journal
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• v.22 no.2
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• pp.77-94
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• 2012

Amorphous ceramic membranes have been developed for gas phase separation and liquid phase separation (water treatment, wastewater treatment and separation of organic solvent or compounds) because of their thermal stability and solvent resistance. In this paper, ceramic membranes were categorized by membrane pore size and materials, and summarized for hydrogen separation, carbon dioxide separation, membrane reactor, pervaporation and water treatment with membrane structure and properties.

• ETRI Journal
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• v.38 no.6
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• pp.1153-1162
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• 2016

This paper addresses the resource allocation (RA) problem in multi-cell cognitive radio networks. Besides the interference power threshold to limit the interference on primary users PUs caused by cognitive users CUs, a proportional fairness constraint is used to guarantee fairness among multiple cognitive cells and the impact of imperfect spectrum sensing is taken into account. Additional constraints in typical real communication scenarios are also considered-such as a transmission power constraint of the cognitive base stations, unique subcarrier allocation to at most one CU, and others. The resulting RA problem belongs to the class of NP-hard problems. A computationally efficient optimal algorithm cannot therefore be found. Consequently, we propose a suboptimal RA algorithm composed of two modules: a subcarrier allocation module implemented by the immune algorithm, and a power control module using an improved sub-gradient method. To further enhance algorithm performance, these two modules are executed successively, and the sequence is repeated twice. We conduct extensive simulation experiments, which demonstrate that our proposed algorithm outperforms existing algorithms.