• Electronics and Telecommunications Trends
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• v.21 no.6 s.102
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• pp.179-189
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• 2006

정보의 바다라고 널리 알려진 인터넷은 클라이언트-서버 커뮤니케이션 모델을 기반으로 하여 패킷의 송/수신자가 정해져 있는 단방향 통신을 사용하고 있다. 하지만, 실제사람들 사이의 맨투맨 커뮤니케이션에서는 송신과 수신이 정해져 있는 경우보다 대화에 참여하는 모든 사람들이 송/수신의 역할을 동시에 수행하는 양방향의 형태가 대부분이며, 이러한 불일치는 인터넷을 통해 제공되는 서비스의 가능성을 제한하는 요소가 되고 있다. 이에 따라, 각각의 단말이 송신과 수신의 역할을 동시에 수행할 수 있는 양방향 통신이 가능한 P2P 커뮤니케이션 방법이 고안되었고, 현재, 이러한 P2P를 이용한 다양한 서비스 모델이 제안되고 있다. 본 고에서는 이러한 P2P 네트워크의 구현 기술 중 하나인 분산 해시 테이블을 바탕으로 한 연구의 동향과 그 응용 현황에 대해서 살펴 보고자 한다.

• Journal of the Korean Institute of Illuminating and Electrical Installation Engineers
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• v.17 no.6
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• pp.77-82
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• 2003

In this paper, as the new type of multi-lines electrode which can formulate strong non-uniform electric field was installed in strong electrolytic water generator, shapes of pre-discharge in bubble and effects of bubble discharge on pH and oxidation/reduction potential change were intended to investigate. Consequently, as multi-lines electrode was installed in side of anode, pre-discharges generated from anode electrode could be observed. This pre-discharge was generated from differences of permittivities between bubble and water in strong non-uniform electric field. And ion concentration in electrolytic water generator was increased by dissolving of ions generated from bubble discharge. So, as generated high concentration ions were separated and assembled to each electrode and reaction of oxidation/reduction was increased, it was shown that strong electrolytic water could be generated.

• Journal of Korean Society of Environmental Engineers
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• v.30 no.7
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• pp.683-687
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• 2008

When suspended solids are removed by natural sedimentation, it is necessary to use mainly huge equipments and waste great cost. This is a problem that must be solved certainly as soon as possible. In this study, suspended solids of yellow soil water were rapidly removed by controlling pH and amounts of magnetic powder, organic and inorganic flocculants. In the case of the suspended solids of 0.3% yellow soil water, the most excellent turbidity was achieved at pH between 7 and 7.5.

• KSBB Journal
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• v.22 no.4
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• pp.244-248
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• 2007

The treatment of a model wastewater containing high concentration, 10 $g/{\ell}$, of phenol in an integrated wet oxidation-aerobic biological treatment was investigated. Partial wet oxidation under mild operating conditions was capable of converting the original phenol to biodegradable organic acids such as maleic acid, formic acid and acetic acid, the solution of which was subjected to the subsequent aerobic biological treatment. The wet oxidation was carried out at 150$^{\circ}C$ and 200$^{\circ}C$ and the initial pH of 1 to 12. The high temperature of 200$^{\circ}C$ and the acidic initial condition in the wet oxidation led to effluents of which biodegradability was higher in the subsequent biological oxidation process, as assessed by chemical oxygen demand (COD) removal. Homogeneous catalyst of $CuSO_4$ was also used for increasing the oxidation rate in the wet oxidation at 150$^{\circ}C$ and initial pH of 3.0. However, the pretreatment with the catalytic wet oxidation resulted in effluents which were less biodegradable in the aerobic biological process compared to those out of the non-catalytic wet oxidation at the same operating conditions.

• Journal of the Korean Vacuum Society
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• v.20 no.2
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• pp.127-134
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• 2011

We investigate the crystallographic orientation and strain states of the Ni/Ag ohmic contacts on p-type GaN. The Ag film in the Ni/Ag contact was severely agglomerated during high temperature annealing in air ambient. As a results, after annealing for 24 h, the Ni/Ag contact shows non-linear I-V curve and low light reflectance of ~21% at 460 nm wavelength. High-resolution X-ray diffraction results show that the interplanar spacing of Ag (111) planes is almost same to that of bilk Ag after annealing for 24 hrs, indicating that the in-plane tensile strain in the Ag film was fully relaxed due to the Ag agglomeration.

• Polymer(Korea)
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• v.35 no.6
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• pp.558-564
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• 2011

The biocompatibility and biodegradability of poly(amino acid) make them ideal candidates for many bio-related applications. Poly(aspartic acid), PASP, is one of synthetic water-soluble polymers with proteinlike structure, and has been extensively explored for the potential industrial and biomedical applications due to its biodegradable, biocompatible and pH-responsive properties. In this work, amino acid-conjugated PASPs were prepared by aminolysis reaction onto polysuccinimide (PSI) using ${\gamma}$-aminobutylic acid(GABA) and ${\beta}$-alanine methyl ester and a subsequent hydrolysis process. Their chemical gels were prepared by crosslinking reaction with ethylene glycol diglycidyl ether (EGDE). The hydrogels were investigated for their basic swelling behavior, hydrolytic degradation and morphology. The crosslinked gels showed a responsive swelling behavior, which was dependent on pH and salt concentration in aqueous solution, and relatively fast hydrolytic degradation.

• Journal of the Korean GEO-environmental Society
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• v.12 no.4
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• pp.17-24
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• 2011

For the purpose of cut off and ground stabilization, water glass chemical grouting method using sodium silicate has problems of weakening durability and ground water pollution because leaching was conducted when the homogel is exposed to the ground water as time elapses. The purpose of this study is to identify the effect of alkali silica sol ground injection materials, it was compared with the sodium silicate ground injection materials using water glasses. For sodium silicate and alkali silica sol by mixing each case is divided into four different specimens were made and tested. The characteristic of alkali silica sol ground injection material was analyzed by unconfined compression test and environmental impact statement of ordinary portland cement and blast furnace slag cement. Alkali silica sol specimens were made mixing A-solution and B-solution in the proportion of one on one. Through this study, alkali silica sol ground injection mixing blast furnace slag cement has excellent strength and environment-friendly.

• Journal of Korean Society of Environmental Engineers
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• v.31 no.8
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• pp.673-678
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• 2009

High-rate phosphorous removal by PAC (poly aluminum chloride) coagulation of A2O effluent was investigate to meet the stringent requirement of wastewater discharge from municipal wastewater treatment plant. A series of jar tests were conducted to find optimum coagulation condition and to enhance removal efficiency. The optimum volumetric concentration of PAC was 30 ppm (2.81mol Al/mol P by mol ratio). Only 17.2% of soluble P was removed for 30 minutes' settling without PAC addition, while this increased to 30.3% by dosing 10ppm PAC. It even increased conspicuously from 49.3% to 88.4% by increasing PAC dose from 20 ppm to 30 ppm. 92.4% of total P was removed by 30 ppm PAC, and the effluent concentration (0.3 mg/L) was acceptable for discharge. The optimum value of coagulation time, settling time, and pH were 4minutes, 20 minutes, and 7.0, respectively. It was not necessary to control pH of raw sample whose pH was 7.0. Soluble P removal was remarkably enhanced at pH 7.0. This implied that sweep floc formation by $Al(OH)_3$ was the main mechanism of coagulation for soluble P removal. Influent and effluent of secondary clarifier were tested for coagulation, and the effluent was better for high-rate P removal. It resulted in 0.18 mg/L of P and 95.4% of P removal by coagulation. It was favorable to recycle the treated water to coagulation tank and the optimum recycle ratio was 0.3.

• Journal of Industrial Convergence
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• v.19 no.4
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• pp.65-74
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• 2021

The purpose of this study was to investigate the effect of bicarbonate intake on blood variables during high-intensity training of sprinters. 30 male/female elites with more than 3 years of experience that are registered to S city as a sprinter was categorized into three groups: control group, training group, and HCO₃^- and training group. Training group and HCO₃^- and training group went through a high-intensity exercise program (80-90% HR max) which escalated every 2-3 weeks, for 90 minutes at a time, 5 days a week, 8 weeks in total. HCO₃^- and Training group took in 300mg of bicarbonate per one kilogram of body weight, in 90 minutes before the start of the high-intensity exercise program, once a day for 8 weeks. As a result of the study, the effect of bicarbonate intake on blood variables during high-intensity training of sprinters showed a positive effect on the increase of pH and the decrease of lactic acid in HCO₃^- and training group. Also, the increase of Ca²⁺, Na⁺, K⁺ was shown in training group and HCO₃^- and training group, whereas there were no indications of significant change in Mg²⁺ in all three groups. It can be confirmed that the intake of bicarbonate during high-intensity training shows effective changes in the increase of pH and the decrease in lactic acid among changes in blood variables. Therefore, it can be seen that the intake of bicarbonate during high-intensity exercise is effective in improving exercise capacity.

• KSBB Journal
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• v.15 no.2
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• pp.174-180
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• 2000

Pichia pastoris and Hansenula polymorpha, the methylotrophic yeasts have been widely used as a host for the production of e eudaryotic proteins due to the advantages related to their inherited characters. This paper describes the method to enhance t the productivity of recombinant proteins by P. pastoris and H. po$\psi$morpha. In the production of recombinant proteins using a f fed batch fermentation system, the effects of specific growth rate on the specific expression rate of re$\infty$mbinant proteins w were studied. In both species, the expression system of recombinant proteins using the fed batch fermentation was optimezed.