• International journal of advanced smart convergence
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• v.5 no.1
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• pp.59-65
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• 2016

In this paper, we're compared network protocol which is network lifetime longer when using LEACH Protocol, SEP, and TEEN in a heterogeneous Wireless Sensor Network with a Large Sensor Area. Also, we propose a method of divided layer the wide-area sensor filed and transmitting a multi-hop to improve the network lifetime. And we're compared network protocol which is network lifetime more improved apply the proposed method to LEACH Protocol, SEP, and TEEN. We tried to compare results, TEEN showed the best network lifetime. Apply the proposed method to divided the sensor field, L-TEEN (Layered TEEN)'s network lifetime rates of improvement is highest.

• Korean journal of applied entomology
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• v.54 no.2
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• pp.63-71
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• 2015

A taxonomic review of Korean Laccophilus Leach is presented. Five species are recognized, three of which [L. hyalinus (De Geer), L. lewisius Sharp and L. minutus ($Linn{\acute{e}}$)] previously recorded in Korea are incorrect identification of L. vagelineatus Zimmermann, L. lewisioides Brancucci and L. difficilis Sharp, respectively. Habitus and SEM photographs, key and diagnoses of the species are provided.

• The Journal of Natural Sciences
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• v.13 no.1
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• pp.83-96
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• 2003

Effect of Nutrient Concentrations, fertigation frequency, and learching percentage on crop growth and nutrient concentrations in root media were evaluated. The treatment of each irrigation with $50 mg.L^{-1}$ of nitrogen in stage 2 and increase to $80 mg.L^{-1}$ nitrogen in stage 3 had the highest crop growth at 34 days after sowing among treatments tested. Feeding with low nutrient concentrations and elevated frequency decreased crop growth. In treatments of each leaching percentage, feeding with low nutrient concentrations and elevated frequency resulted in increased tissue nutrient contents. The less tissue potassium content and higher calcium and magnesium contents were observed in treatment of 50% leach than those in 0% leach. All treatment tested had soil solution pH higher than 6.8. Electrical conductivity in treatments of 50% leach were lower than those of 0% leach. Feeding with low nutrient concentrations and elevated feeding frequency in each leaching percentage resulted in increased electrical conductivity in soil solution of root media. Trends of medium nutrient concentrations were similar to those of electrical conductivity.

• Resources Recycling
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• v.20 no.3
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• pp.48-54
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• 2011

Sulphuric acid leaching was conducted to extract the metal values from spent refinery catalyst. More than 95% of Ni and V and 30% of Mo could be leached out in 1 M sulphuric acid and 1 hr of leaching time. The decrease in Mo leaching was due to typical characteristic of Mo matrix. The activation energies of the leaching reactions showed the dissolution process follows a diffusion control mechanism. In order to leach out all Mo, further the leaching experiments were conducted with sulfur free spent refinery catalyst. For sulfur free spent refinery catalyst, a two step process of leaching with 1 M sulphuric acid followed by sodium carbonate washing showed better leaching than a two step leaching process with sodium carbonate followed by sulphuric acid washing, with almost 99% leaching of Ni, Mo and V. Solvent extraction using LIX 841 were conducted for a leach liquor containing Ni, 2 g/L; V, 9 g/L, Mo, 0.6 g/L. More than 98% of Mo was extracted from the leach liquor at A:O ratio of 5:2 in a 2 stage process. Similarly V was extracted at A:O ratio of 5:3 in a 2 stage process with 82% of total V extraction.

• Korean journal of applied entomology
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• v.59 no.2
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• pp.129-131
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• 2020

Lissodema plagiatum Lewis is newly recorded and L. laevipennis Marseul is removed from the Korean fauna. A habitus photograph and taxonomic note of the newly recorded species are provided, with a key to Korea species of the family Salpingidae Leach.

• Transactions on Electrical and Electronic Materials
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• v.7 no.4
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• pp.196-203
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• 2006

An air-gap type FBAR was designed using Leach equivalent model for analyzing a vertical structure of the FBAR. For the top electrode, Pt, and the bottom electrode, Au, of $1.2{\mu}m$ thickness and the piezoelectric of 0.8,urn thickness, the resonance and anti-resonance occurred at 2.401 GHz and 2.460 GHz, respectively. $S_{11}$ was increased and $S_{21}$ was decreased as the resonance area of FBAR was widened. We observed the characteristics of insertion loss, bandwidth and out-of-band rejection of ladder-type FBAR BPF by changing resonance areas of series and shunt resonators and by adding stages. As the resonance area of series resonator was increased, insertion loss was improved but out-of-band rejection was degraded. And as the resonance area of shunt resonator was increased, insertion loss was degraded a little but out-of-band rejection was improved even without adding stages. We, also, changed the shape of the resonance area from square shape to rectangle shape to examine the effects of the resonator shape on the characteristics of the BPF. The best performances were observed when the sizes of series and shunt resonator are $150{\mu}m{\times}l50{\mu}m\;and\;5{\mu}m{\times}50{\mu}m$, respectively. Out-of-band rejection was improved about 10dB and bandwidth was broadened from 30MHz to 100MHz utilizing inductor tuning on $2{\times}2\;and\; 4{\times}2$ ladder-type BPFs.

• Proceedings of the Korean Institute of Resources Recycling Conference
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• 2005.05a
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• pp.214-223
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• 2005

In order to recover valuable metals from fine-grained electronic waste, bioleaching of Cu, Zn, Al, Co, Ni, Sn and Pb were carried out using Aspergillus niger as a leaching microorganism in a shaking flask. Aspergillus niger was able to grow in tile presence of electronic scrap. The formation of organic acids(citric and oxalic acid) from Aspergillus niger caused the mobilization of metals from waste electronic scrap. In a preliminary study, in order to obtain the data on the leaching of Cu, Zn, Al, Co and Ni, the metal leaching behaviours were accomplished using Organic acid(Citric acid and Oxalic acid) instead of Aspergillus niger. At the electronic scrap concentration of 50g/L, Aspergillus niger were able to leach more than 95% of the available Cu, Co. But Al, Zn, Pband Sn were able to leach about 15-35%. Ni and Fe were detected in the leachate less than 10%.

• Resources Recycling
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• v.2 no.4
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• pp.27-32
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• 1993

A process has been studied to recover gallium from steelmaking dust which had several hundreds ppm of gallium. Aqueous solution containing 38 mg/l gallium was obtained by leaching of dust with 2.25 mol/l sulfuric acid. The leach liquor contained iron and zinc about 1,000 times greater than gallium. Gallium was then concentrated by ion exchanger of chelating resin with functional group of amino carboxylic acid after reduction of ferric ion to ferrous ion and pH adjustment. Gallium was concentrated to be 13 g/l in the resulting eluate by double ion exchanges. The liquor was further treated to remove impurities by solvent extraction technique empolying TOMAC as extractant. The galluim with 99% purity was finally obtainable.

• Resources Recycling
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• v.25 no.3
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• pp.11-19
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• 2016

A fundamental study to recycle a Si-Sludge and waste copper nitrate solution acid solution generated by domestic electronic industries was carried out. The waste copper nitrate solution was used as the lixiviant to leach the metals like Cu, Ca, Fe, etc. from the sludge leaving Si in the residues. The effect of reaction temperature, time and pup density on the metals leaching from the sludge was investigated. To enhance the extractability of Fe, the effect of HCl, $HNO_3$ and $H_2O_2$ introduced additionally during the leaching was also examined. Considering the leaching efficiency of Fe along with Cu, the leaching conditions comprising of 200 ~ 225 g/L pulp density and $90^{\circ}C$ temperature for 30 min were optimized. Under this condition, 98.27 ~ 99.17% Cu could be dissolved in the leach liquor with the obtained purity of Si in the residues as 98.69 ~ 98.86 %. The study revealed that the leaching of Cu contained in the Si-Sludge with the waste copper nitrate solution is a plausible approach by which the obtained leach liquor can further be treated suitably to recover Cu as the high pure value-added products.

• Resources Recycling
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• v.14 no.6 s.68
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• pp.28-36
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• 2005

A hydrometallurgical process to leach cobalt from the waste cathodic active material, $LiCoO_{2}$, and subsequently to separate it by solvent extraction was developed. The optimum leaching conditions for high recovery of colbalt and lithium were obtained: 2.0 M sulfuric acid, 5 $vol.\%$ hydrogen peroxide, $75^{\circ}C$ leaching temperature, 30 minutes leaching time and an initial pulp density of 100 g/L. The respective leaching efficiencies for Co and Li were $93\%$ and $94.5\%$. About $85\%$ Co was extracted from the sulfuric acid leach liquor containing 44.72 g/L Co and 5.43 g/L Li, using 1.5 M Cyanex272 as an extractant at the initial pH 5.0 and in organic to aqueous phase ratio of 1.6:1 under the single stage extraction conditions. The Co in the raraffinate was completely extracted by 0.5 M Na-Cyanex272 at the inital pH 5.0, and an organic to aqueous phase ratio of 1;1. The cobalt sulfate solution of higher than $99.99\%$ purity could be recovered from waste $LiCoO_{2}$, using a series of hydrometallurgical processes: sulfuric acid leaching of waste $LiCoO_{2}$- solvent extraction of Co by Na-Cyanex 271 - scrubbing of Li by sodium carbonate solution - stripping of Co by sulfuric acid solution.