• 농업과학연구
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• 제48권4호
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• pp.935-944
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• 2021

It has been suggested that bisphenol A (BPA), a known endocrine disruptor, interferes with the endocrine system, causing reproductive dysfunction. Recently, BPA has been found in waste water due to incomplete sewage purification, possibly threatening health through its ingestion via tap water. In this study, young male mice (6 - 7 weeks old) were administered water containing BPA (50 mg·kg^-1) for four weeks, while control mice consumed water without BPA. Serum, epididymal spermatozoa and testicular sections were assessed after sacrificing the mice on day 28. No significant differences were obtained between the groups in the body, testis and seminal vesicle weights. However, the epididymal sperm motility and count levels were significantly reduced in BPA-fed mice. Significantly higher hepatotoxicity levels were also observed in mice ingesting BPA as compared to the control mice. The level of serum testosterone was reduced, and testicular sections revealed incomplete and irregular spermatogenesis in BPA-ingested mice. The sperm proteasomal-proteolytic activity level has been implicated in sperm function and is measured in motile spermatozoa using fluorometric substrates. High ubiquitin C-terminal hydrolase activity levels were observed in the control mice without BPA. During a mating trial, a low pregnancy rate (71.4%) was observed in females mated with males who had consumed BPA (100% in the control mice). Overall, BPA adversely affected spermatogenesis and quality, as indicated by decreased sperm motility, concentration and serum testosterone levels, resulting in reduced fertility competence.

• 한국환경농학회지
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• 제13권2호
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• pp.231-239
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• 1994

축산폐수의 경제적 정화기술을 개발하고자 사상여과조(砂床濾過漕)(모래층 20cm+자갈층 30cm)에 갈대를 재배한 뒤 혐기발효된 양돈폐수의 투입 1, 3, 5, 7일 후 정화 효과를 계절별로 분석한 결과는 다음과 같다. 1. 축산폐수 처리일수가 길수록 갈대에 의한 질소 및 인산의 흡수 이용량이 많아지고 근부에서 발생된 산소로 BOD, COD도 낮아져서 정화 효과가 향상되었다. 2. 갈대의 건물생산량은 7일 처리가 가장 높았고 양분흡수량도 처리기간이 경과할수록 중가하는 경향이었다. 3. 갈대사상여과조는 사상여과조 보다도 오염 물질제거율이 높아 여름의 경우 T - N : 30%, $PO_4^{-3}$: 37%, COD : 42%, 부유물은 30% 더 높은 정화율을 나타내었다. 4. 계절별 축산폐수정화율은 여름철이 가장 높고 가을, 봄 순이었다.

• 미생물학회지
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• 제47권3호
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• pp.194-199
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• 2011

알칼리성 protease를 생산하는 호알칼리성 균주를 분리하여 Bacillus pseudofirmus HS-54로 동정하였고, HS-54가 생산하는 알칼리성 protease를 ammonium sulfate 침전, DEAE cellulose chromatography, sephadex G-100 gel filtration을 통과시켜 정제하였는데, 정제된 protease의 분자량은 27 kDa이었다. 정제된 효소의 반응최적 pH는 10.0이었고 pH 7.0-11.0에서 비교적 안정하였다. 또한 정제된 효소의 반응최적 온도는 $50^{\circ}C$이었고 $10-55^{\circ}C$에서 안정하였다. 금속이온에 대한 영향은 $Ca^{2+}$와 $Mg^{2+}$ 등에 의해 효소활성이 촉진되었으나, $Hg^{2+}$, $Zn^{2+}$, $Cu^{2+}$, $Al^{3+}$ 등에 의해서 효소활성이 저해되었다. 본 효소는 PMSF에 의해 강하게 저해를 받는 것으로 보아 serine protease에 속하는 것으로 판단된다.

• Journal of Microbiology
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• 제40권2호
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• pp.129-133
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• 2002

The fungus, Emericellopsis minima W2, capable of degrading poly(3-hydroxybutyrate) (PHB) was isolated from a waste water sample. Production of the PHB depolymerase from E. minima W2 (PhaZ/ sub Emi/) was significantly repressed in the presence of glucose. PhaZ/ sub Emi/ was purified by column chromatography on Octyl-Sepharose CL-4B and Sephadex G-100. The molecular mass of the PhaZ/ sub Emi/), which consisted of a single polypeptide chain, was estimated to be 48.0 kDa by SDS-PAGE and its pI vague was 4.4. The maximum activity of the PhaZ/ sub Emi/ was observed at pH 9.0 and 55$\^{C}$. It was significantly inactivated by 1mM dithiothreitol, 2mM diisopropyl fluorphosphate, 0.1mM Tween 80, and 0.1 mM Triton X-l00, but insensitive to phenylmethylsulfonyl fluoride and N-ethylmaleimide. The PhaZ/ sub Emi/ efficiently hydrolyzed PHB and its copolyester with 30 mol% 3-hydroxyvalerate, but did not act on poly(3-hydroxyoctanoate). It also hydrolyzed p-nitrophenylacetate and p-nitrophenylbutyrate but hardly affected the longer-chain forms. The main hydrolysis product of PHB was identified as a dimer of 3-hydroxybutyrate.

• 한국방사성폐기물학회:학술대회논문집
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• 한국방사성폐기물학회 2005년도 춘계 학술대회
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• pp.145-150
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• 2005

방사성 폐기물을 처분장에 처분하기 위해서는 처분 안전성을 확보하여야 한다. 본 연구는 간접측정 방법 중 하나인 물질수지 기법을 이용하여 방사성폐기물의 핵종재고량 평가 프로그램을 개발하였다. 개발 기법의 현장 적용평가를 위하여 고리4호기(9차계획예방정비)를 대상으로 선정하였다. 개발한 평가방법의 검증을 위해 정지수화학처리시 정화계통 내 핵종 제거량 평가자료를 바탕으로 비교평가를 수행하였다. 평가대상 핵종은 Co-60이며, 평가결과 상대오차 $1\%$미만으로 나타났다. 이와 같은 평가결과를 바탕으로 상용원전에서 제시하고 있는 해당기간 발생된 폐기물의 직접 측정 결과와 비교하였고, 그 결과 직접측정 방법에 의한 Co-60의 함유량은 본 연구의 개발기법에서 산출한 값보다 약 $50\%$ 작은 것으로 평가 하였다.

• 한국환경과학회지
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• 제8권1호
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• pp.75-81
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• 1999

In recent years increasing production and disposal of wastewater have caused an accelerated eutrophication of receiving waters. Therefore, in order to alleviate the detrimental impact of wastewater discharge, there is an increasing demand for removing the main nutrients, nitrogen and phosphorus, as well as the organic content of the waste water prior to disposal. This is effectively achieved by extended conventional treatment technology. However, the working expenses and energy requirements of such advanced treatment systems are rather high. So in a sparsely populated rural community is required development of wastewater treatment system combined with the regional characteristics. In this study, the systems are planted with Reeds and Amaryllis In A.C and estimated purification potential of system. The results obtained are as follows. BOD removal rate is 20% in the early stage, the last removal rate is 35% in A.C process and is 65% in Amaryllis+A.C process and is 50% in Reed+A.C process. T-N removal rate by Amaryllis is average 2.6g/$m^3$ㆍd, T-N removal rate by Reed is average 1.76g/$m^3$ㆍd. T-P removal rate by Amaryllis is average 0.27g/$m^3$ㆍd, T-P removal rate by Reed is average 0.25g/$m^3$ㆍd. BOD removal rate constant with retention time is 1.4494(1/d), T-N removal rate constant is 0.5428(1/d), T-P removal rate constant is 0.5287(1/d).

• Environmental Sciences Bulletin of The Korean Environmental Sciences Society
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• 제10권S_2호
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• pp.79-88
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• 2001

Humic acids react with chlorine to produce Trihalomethanes(THMs), known as carcinogens, during disinfection, the last stage in water purification. Currently, the removal of organic humic acids is considered the best approach to solve the problem of THM formation. Accordingly, the current study examined the adsorption of organic compounds of humic acids onto an inorganic carrier prepared from oyster shell waste. The adsorbent used was activated oyster shell powder(HAP) and silver ion-exchanged oyster shell powder(HAP-Ag), with CaCO$_3$ as the control. The adsorbates were phthalic acid, chelidamic acid, catechol, dodecylpyridinium chloride(DP), and 2-ethyl phenol(2-EP). The adsorption experiments were carried out in a batch shaker at $25^{\circ}C$ for 15 hours. The equilibrium concentration of the adsorbate solution was analyzed using a UV spectrophotometer and the data fitted to the Langmuir isotherm model. Since the solution pH values were found to be greater than the pKa values of the organic compounds used as adsorbates, the compounds apparently existed in ionic form. The adsorptive affinities of the organic acid and phenolic compounds varied depending on the interaction of electrostatic forces, ion exchange, and chelation. More carboxylic acids and catechol, rather than DP and 2-EP, were adsorbed onto HAP and HAP-Ag. HAP and HAP-Ag exhibited a greater adsorptive affinity for the organic compounds than CaCO$_3$, used as the control.

• 분석과학
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• 제13권1호
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• pp.96-100
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• 2000

제올라이트를 사용하여 폐수로부터 중금속 원소들을 제거하기 위하여 조건을 변화시키며 흡착 특성을 조사하였다. 시험한 원소는 독성이 강하여 중금속 오염과 관련이 많은 Cd, Cr, Cu, Pb의 네 가지 중금속 원소들을 선택하였다. 흡착에 영향을 주는 요소로서 제올라이트의 양, 흡착 시간 그리고 pH를 변화시키며 흡착에 의한 제거 효율을 측정하였다. 중금속 용액 50 mL에 대하여 투입된 제올라이트는 2 g 정도가 경제적인 분량이며, 흡착 시간은 30분 정도 반응시키면 최대 흡착을 얻을 수 있었다. Cr과 Cu는 전반적으로 높은 흡착율을 나타내며 낮은 pH 영역에서는 흡착효율이 보다 증가하였다. Cd와 Pb는 95% 내외의 약간 낮은 흡착율을 보이며, Cd는 pH가 낮으면 흡착율이 감소하는 특이한 경향을 보였다.

• Membrane and Water Treatment
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• 제11권1호
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• pp.41-48
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• 2020

Lead is a highly toxic heavy metal that causes serious health problems. Nonetheless, it is increasingly being used for industrial applications and is often discharged into the environment without adequate purification. In this study, Pb(II) was removed by powdered waste sludge (PWS) based on the biosorption mechanism. Different PWSs were collected from a submerged moving media intermittent aeration reactor (SMMIAR) and modified Ludzack-Ettinger (MLE) processes. The contents of extracellular polymeric substances were similar, but the surface area of MLE-PWS (2.07 ㎡/g) was higher than that of SMMIAR-PWS (0.82 ㎡/g); this is expected to be the main parameter determining Pb(II) biosorption capacity. The Bacillaceae family was dominant in both PWSs and may serve as the major responsible bacterial group for Pb(II) biosorption. Pb(II) biosorption using PWS was evaluated for reaction time, salinity effect, and isotherm equilibrium. For all experiments, MLE-PWS showed higher removal efficiency. At a fixed initial Pb(II) concentration of 20 mg/L and a reaction time of 180 minutes, the biosorption capacities (q_e) for SMMIAR- and MLE-PWSs were 2.86 and 3.07 mg/g, respectively. Pb(II) biosorption using PWS was rapid; over 80% of the maximum biosorption capacity was achieved within 10 minutes. Interestingly, MLE-PWS showed enhanced Pb(II) biosorption with salinity values of up to 30 g NaCl/L. Linear regression of the Freundlich isotherm revealed high regression coefficients (R² > 0.968). The fundamental Pb(II) biosorption capacity, represented by the K_F value, was consistently higher for MLE-PWS than SMMIAR-PWS.

• 조명전기설비학회논문지
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• 제12권1호
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• pp.78-84
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• 1998

발전소나 화학플랜트의 급수 및 순환수 계통은 물론 건물의 공조설비 유체계통, 정수 또는 폐수설비에서의 원수유량 및 약품 주입제어 등과 같은 유체계통은 대부분 밸브와 동력 펌프를 이용해 유량 제어를 한다. 따라서 이들 유체계통의 제어방법 및 정밀도에 따라 그 시스템의 성능 및 에너지 절약에 많은 영향을 미치게 된다. 지금까지 이들 계통은 주로 PI제어기를 이용하였으나 이 제어 방법으로는 루프간의 간섭현상으로 정밀하게 유량부하를 제어 할수 없는 문제점이 있다. 본 논문에서는 유체계통 동력부하 설비를 다변수로 구성하여 2-자유 PID제어를 적용하고 신경망을 이용해 튜우닝함으로서 효과적으로 정밀하게 제어 할수 있는 방법을 제시하고 시뮬레이션을 통해 그 방법의 우수성을 입증하였다. 시뮬레이션 결과 설정치를 잘 추종하고 외란에 대해서는 강인성을 갖는 것으로 나타났다.