• Journal of the Korean Wood Science and Technology
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• 제51권3호
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• pp.173-182
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• 2023

Color is an attribute of visual perception and can be an important factor that affects the preference of customers toward bamboo and wood products. Solar radiation can discolor bamboo surfaces and initiate cracking. The purpose of this study is to investigate the effects of an ultraviolet (UV)-protective coating on the photodiscoloration of untreated and heat-treated Phyllostachys bambusoides bamboo surfaces. Artificial UVA radiators are set at a UVA irradiance of 2,000 W/m² to accelerate the aging of the outer surfaces of hot-air-dried and heat-treated bamboo samples. Half of the samples are coated with transparent UV-protective paint. As the UVA radiation progresses, the discoloration prevention efficiency (DPE) of the UV-protective coating on all samples decreases gradually. The DPEs of the hot-air-dried samples are estimated to be 31.4% and 18.8% after 21 and 72 hours of artificial UVA radiation, respectively. The heat-treated samples exhibit similar trends (29.0% after 21 hours and 10.3% after 72 hours). Recoating the UV-protective paint periodically every six months is expected to minimize the discoloration of the bamboo's outer surface.

• 한국환경보건학회지
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• 제25권3호
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• pp.36-43
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• 1999

The present study was performed to investigate biodegradation rate of dichlorvos and methidathion. In the biodegradation test of two pesticides by the modified river die-away method from June 17 to August 22, 1998, the biodegradation rate constants and half-life were determined in Nakdong(A) and Kumho River(B). Biodegradation rate of dichlorvos was 4.51% in A sampling point, 6.88% in B sampling point after 7 days. Biodegradation rate constants and half-life of dichlorvos were 0.0066 and 105 days in A sampling point, 0.0102 and 67.9 days in B sampling point, respectively. Biodegradation rate of methidathion was 23% in A sampling point, 36% in B sampling point after 7 days. Biodegradation rate constants and half-life of methidathion were 0.0377 and 18.4 days in A sampling point, 0.0641 and 10.8 days in B sampling point, respectively. Biodegradation rate of methidathion was faster than that of dichlorvos. This suggested that the difference in biodegradation of pesticides was due to difference in the water quality and standard plate counts in the Nackdong and Kumho Rivers. The result of correlation analysis between biodegradation rate constants of the pesticides and water quality(DO, BOD, SS, ABS, NH$_3$-N, and NO$_3$-N) showed significant correlation with BOD, SS and NH$_3$-N at the 5% significant level. A significant linear equation was obtained from regression analysis at the 5% significant level, whereas, dependent variables were BOD, SS and NH$_3$-N, and the biodegradation rate constant was independent variable. It is suggested that dichlorvos will be mainly degraded by hydrolysis, and for methidathion was both hydrolysis and biodegradation. A significant QSAR equation was obtained from regression analysis at the 10% significant level, whereas, dependent variable is biodegradation rate constants of BPMC, chlorothalonil, dichlorvos and methidathion, vapor pressures, partition coefficients and water solubilities of the pesticides are independent variables. Also, a significant linear equation was obtained from regression analysis at the 1% significant level, whereas, dependent variable is biodegradation rate constants of BPMC, chlorothalonil, dichlorvos and methidathion, hydrolysis rate constants of the pesticides are independent variables. It is suggested that the pesticides will be degraded by main degradation factor when the pesticides was affected both hydrolysis and biodegradation.

• 농약과학회지
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• 제17권1호
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• pp.6-12
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• 2013

복숭아 재배 중 methoxyfenozide와 novalruon을 1회 처리와 3회 처리로 구분하여 살포하고, 살포 후 0, 2, 4, 6, 8, 10, 12, 14일까지 복숭아 시료를 채취하였다. Methoxyfenozide와 novaluron은 acetone으로 추출, dichloromethane으로 분배하여 HPLC/DAD로 분석하였다. 분석결과 정량분석한계는 모두 0.005 mg/kg이었고, 0.05 및 0.25 mg/kg 수준에서 methoxyfenozide의 평균 회수율은 각각 $92.7{\pm}2.9%$와 $102.8{\pm}3.1%$, novaluron은 $98.2{\pm}4.8%$와 $96.7{\pm}9.0%$이었다. 복숭아에서 methoxyfenozide의 생물학적 반감기는 4.41일(1회)과 4.24일(3회)이었고, novaluron은 14.81일(1회)과 14.50일(3회)이었으며, 복숭아의 증체율에 따른 희석효과가 잔류량 감소에 영향을 주었으며, methoxyfenozide와 novaluron을 농약안전사용기준에 따라 처리 시 최종잔류농도는 MRL 이하로 떨어질 것으로 예측된다.

• 한국수소및신에너지학회논문집
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• 제31권1호
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• pp.132-137
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• 2020

Lithium secondary batteries have become an important power source for portable electronic devices such as cellular phones, laptop computers. Presently, commercialized lithium-ion batteries use a LiCoO₂ cathode. However, due to the high cost and environmental problems resulting from cobalt, an intensive search for new electrode materials is being actively conducted. Recently, solid solution LiMn_1-xNi_xO₂ have become attractive because of high capacity and enhanced safety at high voltages over 4.5 V. The Li_1.6Ni_0.35Mn_0.65O₂ compounds were conventionally prepared by a sol-gel method, which can produce the layered Li-Ni-Mn-O compounds with a high homogeneity. And by adding a graphene 2wt% the first charge-discharge voltage profiles was increased over Li_1.6Ni_0.35Mn_0.65O₂ compound. Also, the variation s of the discharge capacities with cycling showed a higher capacity retention rater. In this study, material lifecycle evaluation was performed to analyze the environmental impact characteristics of Li_1.6Ni_0.35Mn_0.65O₂ & graphene 2wt% half-cell manufacturing process. The software of material life cycle assessment was Gabi. Through this, environmental impact assessment was performed for each process. The environmental loads induced by Li_1.6Ni_0.35Mn_0.65O₂ & graphene 2wt% synthesis process were quantified and analyzed, and the results showed that the amount of power had the greatest impact on the environment.

• 정보관리학회지
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• 제28권2호
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• pp.97-115
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• 2011

국내 과학기술 분야 연구자들의 인용행태를 종합적으로 파악하고 분석하기 위해서는 대규모의 신뢰할 수 있는 인용색인 데이터베이스가 필요하다. KISTI는 한국 과학기술 인용색인 데이터베이스인 KSCD를 구축하고 한국과학기술인용보고서(KJCR) 및 한국과학기술인용색인서비스(KSCI)를 제공하고 있다. 본 논문에서는 국내 핵심 학술지 459종의 학술지를 커버하는 KSCD를 활용하여 국내 과학기술분야 연구자들의 한국 학술지 인용행태를 분석 연구를 수행하였다. 연구 범위로는 첫째, 대상 DB 수록 학술지의 통계적 주요 수치정보를, 둘째, 인용문헌의 형태별 분석을, 셋째, 인용문헌의 국내와 해외비율 및 타분야 인용비율을, 넷째, 국내 인용문헌의 즉시인용, 인용절정기, 반감기를 마지막으로 KJCR 인용지표를 통한 학술지의 영향력 분석이다. 국내학술지 인용분석을 통한 연구의 주요 성과로는 국내 인용 학술지의 즉시인용률(평균 2.36%), 인용절정기(평균 1.7년), 반감기(평균 5.2년)의 규명과 모든 주제분야에서 자기학술지 인용률이 평균 50%를 넘는다는 것을 밝힌 것이다. 본 연구를 통해 국내 과학자들의 국내 학술지 인용행태를 과학기술 전분야에 걸쳐 종합적으로 파악할 수 있었다.

• 한국식품위생안전성학회지
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• 제14권3호
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• pp.249-254
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• 1999

Modified river die-away 법으로 1998년 6월 17일부터 7월 22일 까지 낙동강(A)과 금호강(B)에서 채수한 강물로 BPMC와 chlorothalonii의 생분해 시험을 한 결과는 다음곽 kx다. BPMC의 경우 A지점의 실험군에서는 배양 7일 경과후 27%의 생분해를 나타냈으며 B지점의 실험군에서는 배양 7일 경과 후 40%의 생분해를 나타냈다. 생분해 속도상수와 반감기는 A지점에서 0.0460 및 15.1일 이었고, B지점에서 0.0749 및 9.3일로 조사되었다. Cholorothalonii의 경우 A지점의 실험군과 B지점의 실험군에서 배양 24시간 경과 후 모두 100%의 빠른 생분해를 나타내었다. 생분해속도상수와 반감기는 A지점에서 0.1416 및 4.9시간이었고, B지점에서 0.1803 및 3.8시간으로 조사되었다. Chlorothalonil이 BPMC보다 생분해속도가 빨랐으며, 수질오염이 심한 지역일수록 생분해율이 높은 것은 두 지점의 수질오염 및 종속영양세균수의 차이가 영향을 미치는 것으로 추정된다. 두 가지 농약의 생분해속도와 실험수의 DO, BOD, SS, ABS, $NH_3-N$와의 상관성을 구한 결과 각각 5% 유의수준에서 PMC의 경우 BOD, SS 및 $NH_3-N$이었고 chlorothalnil의 경우 SS, BOD 및 $NH_3-N$를 독립변수로, 생분해속도를 종속변수로 회귀분석을 실시한 결과는 5% 유의수준에서 각각의 농약에 대해 유의한 회귀식을 구할 수 있었다. BPMC는 실제 환경 중에서 생분해에 의한 영향을 더 받을 것으로 생각되며 chlorothalonil은 주요한 분해경로가 생분해인 것을 알 수 있었다.

• Environmental Analysis Health and Toxicology
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• 제19권1호
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• pp.33-40
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• 2004

Benzoyl peroxide is a High Production Volume Chemical, which is produced about 1,371 tons/year in Korea as of 2001 survey. The substance is mainly used as initiators in polymerization, catalysts in the plastics industry, bleaching agents for flour and medication for acne vulgaris. In this study, Quantitative Structure-Activity Relationships (QSAR) are used for getting adequate information on the physical -chemical properties of this chemical. And hydrolysis in water, acute toxicity to aquatic and terrestrial organisms for benzoyl peroxide were studied. The physical -chemical properties of benzoyl peroxide were estimated as followed; vapor pressure=0.00929 Pa, Log $K_{ow}$ = 3.43, Henry's Law constant=3.54${\times}$10$^{-6}$ atm-㎥/mole at $25^{\circ}C$, the half-life of photodegradation=3 days and bioconcentration factor (BCF)=92. Hydrolysis half-life of benzoyl peroxide in water was 5.2 hr at pH 7 at $25^{\circ}C$ and according to the structure of this substance hydrolysis product was expected to benzoic acid. Benzoyl peroxide has toxic effects on the aquatic organisms. 72 hr-Er $C_{50}$ (growth rate) for algae was 0.44 mg/1.,48 hr-E $C_{50}$ for daphnia was 0.07mg/L and the 96hr-L $C_{50}$ of acute toxicity to fish was 0.24mg/L. Acute toxicity to terrestrial organisms (earth worm) of benzoyl peroxide was low (14 day-L $C_{50}$ = > 1,000 mg/kg). Although benzoyl peroxide is high toxic to aquatic organisms, the substance if not bioaccumulated because of the rapid removal by hydrolysis (half-life=5.2 hr at pH 7 at $25^{\circ}C$) and biodegradation (83% by BOD after 21 days). The toxicity observed is assumed to be due to benzoyl peroxide rather than benzoic acid, which shows much lower toxicity to aquatic organisms. One can assume that effects occur before hydrolysis takes place. From the acute toxicity value of algae, daphnia and fish, an assessment factor of 100 was used to determine the predicted no effect concentration (PNEC). The PNEC was calculated to be 0.7$\mu\textrm{g}$/L based on the 48 hr-E $C_{50}$ daphnia (0.07 mg/L). The substance shows high acute toxicity to aquatic organisms and some information indicates wide-dispersive ore of this substance. So this substance is, a candidate for further work, even if it hydrolysis rapidly and has a low bioaccumulation potential. This could lead to local concern for the aquatic environment and therefore environmental exposure assessment is recommended.

• 한국잡초학회지
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• 제4권2호
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• pp.154-162
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• 1984

유기물(有機物)의 종류(種類)와 첨가수준(添加水準), 석탄시용수준(石炭施用水準), 수분(水分), 살균제(殺菌劑) 및 살충제(殺蟲劑)와의 혼용(混用)에 의(依)한 Butachlor와 Nitrofen의 토양중(土壤中) 분리양상(分離樣相)을 구명(究明)하기 위하여 실내시험(室內試驗)을 실시(實施)하였던 바 다음과 같은 결과(結果)를 얻었다. 1. 토양(土壤)의 살균처리(殺菌處理)는 제초제(除草劑)의 분해(分解)를 현저(顯著)히 저해(沮害)하였고 무균상태하(無菌狀態下)에서의 Nitrofen 반감기(半減期)는 Butachlor 보다 길었다. 2. 토양(土壤)의 담수처리(湛水處理)는 포장용수량상태(圃場容水量狀態)에서 보다 제초제(除草劑)의 분해효과(分解效果)가 컸으며 특(特)히 Nitrofen의 분해(分解)에 미치는 담수(湛水)의 효과(效果)는 현저(顯著)하였다. 포장용수량조건하(圃場容水量條件)에서의 Nitrofen 반감기(半減期)는 Butachlor 보다 2배정도(培程度) 길었다. 3. 유기물급원(有機物給源)으로서 볏짚은 벼그루터기에 비(比)하여 토양중(土壤中) 제초제(除草劑) 분해촉진효과(分解促進效果)가 높았으나 볏짚첨가수준(添加水準)이 1,000kg/10a를 상회(上廻)할 때 토양중(土壤中) Butachlor 분해(分解)는 지연(遲延)되었다. 4. 석탄시용(石炭施用)은 토양중(土壤中) 제초제(除草劑)의 분해(分解)를 촉진(促進)하였으나 pH와의 직접적(直接的)인 관계(關係)는 없었다. 5. 살균제(殺菌劑) 및 살충제(殺蟲劑)와의 혼용(混用)에 의한 담수토양중(湛水土壤中) Butachlor의 반감기(半減期)는 단용(單用)에 비(比)하여 단축(短縮)되는 경향(傾向)이었으나 Nitrofen은 영향(影響)이 없었다.

• 대한수의학회지
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• 제32권4호
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• pp.671-675
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• 1992

This experiment was carried out to establish a proper method of indocyanine green(ICG) excretion test for a applicable liver function test in dogs. The half life(T1/2), fractional clearance rate(KICG) and retention rate after injection of ICG with or without administred carbon tetrachloride($CCl_4$) were also invested. The results obtained were as follows ; 1. The maximum absorbance of ICG in plasma was at 810nm. 2. Half life and fractional clearance rate when administered 0.25 and 0.50mg of ICG per Kilogram body weight were $6.33{\pm}0.58$ minutes and $0.11{\pm}0.99$/minute in the former, $10.01{\pm}1.0$ minutes and $0.07{\pm}0.007$/minute in the latter, respectively. The ICG removal rate was exponentially linear for the first 15 minutes after injection both, of 0.25 and 0.50mg of ICG. 3. One day following the administration of $0.0042m{\ell}\;CCl_4$ kilogram body weight which injected 0.50mg of ICG, half life was more longer and fractional clearance rate was significantly reduced than that of ICG single injection. 4. Plasma retention rate when 15, 30, 45 minutes after injection dose of 0.25 and 0.50mg ICG per Kilogram body weight, $14.7{\pm}4.8$, $5.1{\pm}3.1$, $2.6{\pm}1.6%$ in the former, $26.9{\pm}1.8$, $11.1{\pm}2.4$, $4.8{\pm}1.3%$ in the latter, respectively. However, after administration of $CCl_4$, plasma retention rate of ICG at a dose of 0.50mg, it was $39.3{\pm}0.9$, $16{\pm}2.9$, $10.7{\pm}0.1%$, respectively. 5. Plasma enzyme(AST, ALT, r-GTP) activities administered with $CCl_4$ were increased, but there was no change which injected any dose of single ICG injection. From these results, ICG excretion test to dog is applicable to evaluation of liver function in both clinical and research.

• 한국환경농학회지
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• 제12권3호
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• pp.209-218
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• 1993

토양(土壤)중에 있어서 살충제(殺蟲劑) ethoprophos의 행동특성(行動特性)을 조사(調査)한 결과(結果)를 요약(要約)하면 다음과 같다. 실내조건(室內條件)중의 토양(土壤)중 ethoprophos분해(分解)는 일차반응식(一次反應式)에 따랐으며, 반감기(半減期)는 10, 18, $25^{\circ}C$ 에서 각각 12.4, 5.5, 2.5일이었고, Arrhenius activation energy는 73.8 KJ/mol이었다. 수분함량(水分含量)이 7, 14, 19%인 토양(土壤)에서 ethoprophos의 반감기(半減期)는 각각 46.4, 17.6, 6.9일이었으며 Empirical방정식에서 수분의존도(水分依存度)(B)값은 1.67이었다. Ethoprophos의 토양(土壤)중 흡착등온선(吸着等溫線)은 Freundlich식(式)에 따랐으며 흡착분배계수(吸着分配係數)(Kd)값은 0.27이었다. Mini-lysimeter를 이용한 실외조건(室外條件)하의 이동실험(移動實驗)에서 ethoprophos는 대부분이 $0{\sim}2cm$층위(層位)에 분포(分布)되었으며 6cm층위(層位)까지 이동(移動)되었다. 실외포장(室外圃場)에서 ethoprophos의 분해(分解)는 기상변화(氣象變化)와 밀접한 관계를 보였으며, 3월과 10월의 처리에서 반감기(半減期)는 각각 17일과 5일 정도이었고, 처리 후 약 37일에는 90%까지 분해(分解) 소실(消失)되었다. 토양(土壤)중 농약(農藥)의 행동(行動) 예측(豫測) computer model에 의한 ethoprophos의 이동성(移動性)과 잔유성(殘留性)의 예측치(豫測値)는 분석치(分析値)와 유사(類似)하였다.