• Environmental Engineering Research
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• 제14권1호
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• pp.48-52
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• 2009

Solubilization of sewage sludge creates favorable conditions for anaerobic microorganisms to produce biogas. In this paper, we quantify the effect of heating pretreatment on the degree of solubilization of sewage sludge. The pretreatment process was carried out using a lab-scale industrial microwave unit (2450 MHz frequency). Response surface analysis was applied to determine the combination of temperature-increase rate (ramp rate) (2.9 to 17.1 ${^{\circ}C}$/min) and terminal temperature (52 to 108${^{\circ}C}$). Both ramp rate and temperature significantly affected the solubilization degree of sludge. Within the design boundaries, the conditions predicted to maximize the solubilization degree of 15.8% were determined to be 2.9 ${^{\circ}C}$/min and 104${^{\circ}C}$.

• 한국세라믹학회지
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• 제36권9호
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• pp.946-953
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• 1999

The etching characteristics of Er-doped sodium borosilicate glass film for the planar optical waveguides were investigated using reactive ion etching. The etch rate decreased as the pressure in creased but increased as the RF power increased. The etch rate increased as the flow rate C2F gas and the amount of O2 addition increased but decreased over critical point (C2F6 7,5 accm O2 20%) The etch rate was 180${\AA}$/min under C2F6 7.5 sccm O2 20% RF power 270 W, pressure 150 mTorr. With this optimum etching condition and subsequent heat treatment at 975$^{\circ}C$ for 30 minutes planar optical waveguides having improved sidewall roughness were fabricated successfully.

• 전력전자학회:학술대회논문집
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• 전력전자학회 2019년도 추계학술대회
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• pp.194-195
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• 2019

배터리는 사용 기간과 회수가 증가함에 따라 수명이 점차 감소한다. SOH(State-Of-Health)는 배터리의 초기 상태와 현재 상태를 비교하여 배터리의 수명 상태를 나타내는 지표이며, 이는 배터리를 사용함에 있어서배터리의 현재 충전상태를 나타내는 SOC(State-Of-Charge)와 함께 정확한 추정을 필요로 한다. 본 논문에서는 리튬이온 배터리를 C-rate에 따라 노화시키며 각 C-rate별 SOH 추정 경향성을 분석하였다. 배터리의 SOC와 SOH는 확장 칼만 필터를 병렬적으로 사용하는 이중 확장 칼만 필터를 활용하여 추정한다. 배터리의 노화실험은 완전충전과 완전충전을 반복하는 전류 프로파일을 인가하였으며, 실험은 상온(25℃)에서 실행하였다.

• 한국철도학회:학술대회논문집
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• 한국철도학회 2000년도 춘계학술대회 논문집
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• pp.399-406
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• 2000

In this study, using the CRS consolidation tests on reconstituted marine clay, the characteristics of C$\sub$v/, k, e and $\varepsilon$, the anisotropic characteristics of specimen according to the rate of strain were estimated. Also, the validity of the Wissa et al.(1971) consolidation theory on CRS(Constant Rate of Strain) consolidation tests were reviewed. From that results, it was shown that the value of C$\sub$v/, k and u$\sub$b/ was increased as the rate of strain was increased. While the difference of the value( C$\sub$v/, k and u$\sub$b/) between vertically reconstituted specimen and horizontally reconstituted specimen became small as the rate of strain was increased. It is known that k is different due to the hydraulic gradient(i) during the CRS consolidation tests. The subject of this study is to distinguish steady state from transient state in CRS consolidation tests. Consequently, the difference of the value(C$\sub$v/ and k) is higher in case of vertically reconstituted specimen than horizontally reconstituted specimen.

• 한국환경과학회지
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• 제11권10호
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• pp.1103-1108
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• 2002

In order to evaluate the degradation organophosphorus pesticide, EPN, in water environment, the effects of water temp.(10$^{circ}C,\;30^{\circ}C$), pH(3-11) and sunlight on its degradation were investigated during 10 days. The degradation rate of EPN(200 rpm) was faster at higher water temp. and higher pH, i.e., its degradation rate at pH 3, 5, 7, 9, 11 was 57, 63, 66, 69, 75%(1$0^{\circ}C$), and 70, 74, 79, 91, 97%(3$0^{\circ}C$) after 10 days, respectively. The effect of water temp. on its degradation was little in acidic condition, but was rather great in alkaline condition, with time. EPN was degraded fast at the alkaline condition by photolysis. At the condition of pH 11, EPN was degraded fast at the early stage in the first 2 days, but after that the degradation rate was weakened.

• 전력전자학회:학술대회논문집
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• 전력전자학회 2012년도 전력전자학술대회 논문집
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• pp.413-414
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• 2012

본 논문에서는 C-rate, 온도, SOC (State-of-Charge, 잔존용량)를 고려하여 NiMH 배터리를 모델링하였고, 시뮬레이션 결과를 배터리 실험 결과와 비교하였다. 제안한 배터리 모델은 1차 테브난 등가회로를 기반으로 구성하였으며 Matlab/Simulink 환경에서 구현하였다. 모델을 구현하기 위한 실험으로는 정전류, 펄스전류 실험을 하여 가변온도와 다양한 C-rate에서 변하는 파라미터를 도출하였고, 도출한 파라미터는 룩업 테이블을 이용하여 배터리 모델에 적용하였다. 제안된 배터리 모델을 짧은 시간동안 불규칙하게 변하는 전류 패턴에 대한 시뮬레이션과 실험 파형을 통하여 배터리 모델의 성능을 검증하였다.

• 한국물환경학회지
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• 제23권3호
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• pp.367-370
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• 2007

Numerous sets of simulation were conducted in order to find out the optimum operational conditions of the existing BNR process using GPS-X program. The model of ASM3 and modified Bio-P module were applied for simulations. From the result of this study, effluent quality was closely related with the step feeding rate and influent C/N ratio. The effluent TN concentration seemed to be significantly affected by step feeding rate at the low C/N condition. But at the high C/N condition, the effluent concentration of TP rather than that of TN was affected by the control of step feeding rate.

• Journal of Plant Biology
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• 제8권1_2호
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• pp.5-10
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• 1965

The effect of radioactive sulfur-35 on the growth and tissue respiration in rye, Secale cereale L., seedlings were studied in this investigation. The growth and respiration rate of the materials treated with the different intensities of radioactivity, represented by the different concentration(${\mu}c$) of radioactive sulfur were shown similar effects in treated groups as those of Gamma-ray or X-ray irradiation on plant materials. However, in the groups of ($0.1{\mu}c$ and ($0.4{\mu}c$ S35-solution, the growth and respiration rate were stimulated somewhat more clearly than in case of control. And the higher concentration groups, $1.6{\mu}c$, $6.4{\mu}c$, and $25.6{\mu}c$ were depressed of the growth and tissue respiration rate. The present data could be explained on the basis that the higher concentration treatments with the radioactive isotope did produce injury to the plant metabolism generally, but the moderate treatment would stimulate to the plant growth and tissue respiration.

• 한국주조공학회지
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• 제5권3호
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• pp.13-18
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• 1985

Decarburization phenomena were investigated at $800^{\circ}C$ by the $PH_2O/PH_2$ + Ar gas mixture in the case iron range which contains Si, Mn and Cr as an alloying elements. Dissociation of cementite in a matrix which contains graphitizer as Si begins at the carbon rich cementite dendrite arms. Several primary austenite $({\gamma})$ skeletons are surrounded by those nucleated graphite nodules, and that forms a limited area of nucleation region. Decarburization reactions at $800^{\circ}C$ in Fe-C, Fe-Mn-C and Fe-Cr-C alloy are followed by parabolic rate law under the gas mixture of $PH_2O/PH_2=0.01$ and the modified rate const. ${\kappa}$ were in the range of $1{\sim}6{\times}10^{-10}cm^2/s$.

• 대한전기학회:학술대회논문집
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• 대한전기학회 2006년도 추계학술대회 논문집 전기물성,응용부문
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• pp.30-31
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• 2006

To improve the mean-life and the reliability of power cable, we have investigated specific heat (Cp). Specific-heat measurement temperature ranges of XLPE insulator were from $20[^{\circ}C]$ to $90[^{\circ}C]$, and the heating rate was $1[^{\circ}C/min]$. In case of semiconducting materials, the measurement temperature ranges of specific heat were from $20[^{\circ}C]$ to $60[^{\circ}C]$ and the heating rate was $1[^{\circ}C/min]$. From these experimental results, both specific heat were increased by heating rate because volume of materials was expanded according to rise in temperature. We could know that a small amount of CNT has a excellent thermal properties.