• 한국군사과학기술학회지
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• 제14권6호
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• pp.1186-1191
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• 2011

Composition which was used as a white smoke grenade consists of Aluminium(Al), Hexachloroethane(HCE) and Zinc Oxide(ZnO), etc. there is a possibility of misfire due to long term storage and there are very few reports on the mechanism behind misfire. In this study, an experimental method known as accelerated degradation testing is used to investigate the chemical mechanism resulting in misfire. The mechanism of chemical change during long term storage was analyzed with XRD and FT-IR. Analysis results suggest that a part of HCE consisting of the white smoke grenade disappeared and the other part was combined into $ZnCl_2$, $AlCl_3$, as a recycled intermediate product under closed system.

• 한국산학기술학회논문지
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• 제18권10호
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• pp.178-184
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• 2017

본 연구는 2007년 1월부터 2015년 12월까지 본원에서 쯔쯔가무시병으로 진단을 받고 치료 중인 상태에서 뇌경색이 발생하거나, 뇌경색이 생겨 입원 치료를 받던 중 쯔쯔가무시병이 발견된 16명의 환자를 대상으로 하였다. 급성기 뇌경색의 진단은 뇌자기공명영상 및 뇌자기공명혈관영상으로 하였으며 쯔쯔가무시병의 진단은 PCR (Polymerase chain reaction)로 하였다. 일반적인 뇌경색과 쯔쯔가무시병을 동반한 뇌경색의 차이점을 구별하기 위해 내원시 혈압과 체온을 측정하여 보았다. 일반적으로 급성기 뇌경색에서는 혈압이 올라가는데 흥미롭게도 본 연구에서는 수축기 혈압이 130mmHg 미만인 환자가 12명으로 급성기 뇌경색에서 흔히 보이는 혈압 양상과는 다른 모습을 보였다. 쯔쯔가무시병을 동반한 뇌경색의 특징을 알아보기 위해 발병 위치 및 단일 혹은 다발성 뇌경색 여부를 확인하여 보았는데, 앞순환 동맥 영역의 뇌경색 발생 환자가 13명이었으며 뒤순환 동맥 영역의 뇌경색 발생 환자는 3명이었다. 응고장애를 진단하기 위해 트롬보플라스틴시간(Prothrombin Time, PT), 활성화부분트롬보플라스틴시간(activated partial thromboplastin time, aPTT), D-dimer, 섬유소원(fibrinogen), 섬유소분해산물(fibrin degradation product, FDP)를 기록하였다. 뇌경색시 일반적으로 수치가 증가하는 것으로 알려진 D-dimer의 경우 13명의 환자에서 큰 폭의 증가 소견을 보였다. 섬유소분해산물(FDP)는 15명의 환자에서 큰 폭의 증가 소견을 보였다. 쯔쯔가무시병의 병태생리학적 기전은 혈관염으로 알려져 있는데 이로 인한 대뇌혈관의 내피세포 손상 및 증식이 있을 수 있고 그 과정에서 응고장애가 동반되어 뇌경색이 발생할 수 있다. 또는 내피세포 손상 및 증식이 없더라도 혈관염으로 인한 혈관연축이 발생하여 혈관수축이 오며 뇌경색이 발생 할 수도 있다.

• KSBB Journal
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• 제23권6호
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• pp.546-550
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• 2008

본 연구에서는 아스타잔틴의 각종 유기용매와 물에 대한 용해도와 산화, 빛, 온도 및 pH에 의한 아스타잔틴의 안정성을 검토하였다. 아스타잔틴은 유기용매인 아세톤과 아세트산에 비교적 용해도가 높았으며 물에는 거의 용해되지 않았다. 아스타잔틴의 용해도에 미치는 pH의 영향을 검토한 결과, 산성 조건 (pH 2)에서는 중성이나 염기성 조건에 비하여 용해도가 10-20배 증가하였다. 아스타잔틴은 산화와 빛에 대한 안정성이 매우 낮았으며, pH 3에서도 안정성이 급격히 떨어지는 것으로 조사되었다. 온도에 대한 영향을 조사한 결과, 상온 보관시에도 아스타잔틴이 쉽게 분해되었으며, 특히 $100^{\circ}C$에서 5초 동안 가열할 경우 아스타잔틴이 90% 이상 분해되었다. 결론적으로 아스타잔틴을 식품이나 화장품 등의 산업적 활용을 위해서는 안정성과 용해도 개선이 요구되는 것으로 판단되었다.

• 한국환경과학회지
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• 제29권1호
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• pp.69-77
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• 2020

Oxidative degradation of phenol, three monochlorophenols (2-chlorophenol, 2-CP; 3-chlorophenol, 3-CP; 4-chlorophenol, 4-CP), four dichlorophenols (2,3-dichlorophenol, 2,3-DCP; 2,4-dichlorophenol, 2,4-DCP; 2,5-dichlorophenol, 2,5-DCP; 2,6-dichlorophenol, 2,6-DCP), and two trichlorophenols (2,4,5-trichlorophenol, 2,4,5-TCP; 2,4,6-trichlorophenol, 2,4,6-TCP) was conducted with heat activated persulfate. As the number of chlorinations increased, the reaction rate also increased. The reaction rate was relatively well fitted to the zero-order kinetic model, rather than the pseudo-first order kinetic model for the reactions at 60 ℃, which can be explained by insufficient activation of the persulfate at 60 ℃, and the oxidation reaction of 2,4,6-TCP at 70 ℃ was relatively well fitted to the pseudo-first order kinetic model. The oxidation reaction rate generally increased with increase of persulfate concentration in the solution. 2,6-dichloro-2,5-cyclohexadiene-1,4-dione was found as a degradation product in a GC/MS analysis. This compound is a non-aromatic compound, and one chlorine was removed. This result is similar to the result of previous studies. The current study proved that heat activated persulfate activation could be an alternative remediation technology for phenol and chlorophenols in soil and groundwater.

• 한국미생물·생명공학회지
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• 제18권6호
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• pp.607-612
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• 1990

생분해성 고분자로서 중요한 poly-$\beta$-hydroxybutyrate(PHB)의 생합성에 있어서 포도당과 암모늄농도의 영향을 규명하기 위하여 Alcaligenes eutrophus를 회분식으로 배양하였다. PHB는 질소원이 고갈되면서 생성되었고 건조세포무게의 약 80까지 축적되었다. 초기 포도당농도가 높을수록 세포성장과 PHB 합성은 억제되었지만 최종 세포농도와 건조세포무게에 대한 PHB 축적비는 증가하였다. 초기 암모늄농도가 낮을수록 최종 세포와 PHB 농도가 낮았지만 건조세포무게에 대한 PHB 축적비는 증가하였다. 배양도중 산소공급을 중단했을 때 세포성장과 PHB 합성이 중단되었다.

• 산업경영시스템학회지
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• 제43권1호
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• pp.26-33
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• 2020

The plastic waste problem is deepening all over the world. Plastic wastes have serious impacts on our lives as well as environ- mental pollution. The production and use of plastics increases every year, but once they are produced, they usually roam the earth for hundreds or thousands of years to pollute the environment. Although there is growing interest in plastic issues around the world and environmental regulations are being tightened, but no clear solution has yet been found. This study suggests Environmental degradation index (EDI). EDI can help raise consumers' attention to plastic wastes. In addition, EDI will contribute to reduce them in the future. As far as we know, this is the first study. We developed EDI for the confectionery packaging. This study defines four factors that may affect the environment of confectionery packaging: greenhouse gas emissions, energy consumption, methane emissions, and packaging space ratio. Then we quantify the value of each element and compute EDI as the sum of the four component values. In order to evaluate the feasibility of EDI proposed in this study, confectionery-packaging materials distributed in Korea were collected and analyzed. First, the types of confectionery are classified into pies, biscuits, and snacks and basic data was collected. Then the values of the four components were calculated using existing research data on the environment. We can use the proposed EDI to determine how much a product packing affects the environment.

• 한국환경과학회지
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• 제26권7호
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• pp.859-868
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• 2017

In this study, the reductive dechlorination of triclosan using zero-valent iron (ZVI, $Fe^0$) and modified zero-valent iron (i.e., acid-washed iron (Aw/Fe) and palladium-coated iron (Pd/Fe)) was experimentally investigated, and the reduction characteristics were evaluated by analyzing the reaction kinetics. Triclosan could be reductively decomposed using zero-valent iron. The degradation rates of triclosan were about 50% and 67% when $Fe^0$ and Aw/Fe were used as reductants, respectively, after 8 h of reaction. For the Pd/Fe system, the degradation rate was about 57% after 1 h of reaction. Thus, Pd/Fe exhibited remarkable performance in the reductive degradation of triclosan. Several dechlorinated intermediates were predicted by GC-MS spectrum, and 2-phenoxyphenol was detected as the by-product of the decomposition reaction of triclosan, indicating that reductive dechlorination occurred continuously. As the reaction proceeded, the pH of the solution increased steadily; the pH increase for the Pd/Fe system was smaller than that for the $Fe^0$ and Aw/Fe system. Further, zero-order, first-order, and second-order kinetic models were used to analyze the reaction kinetics. The first-order kinetic model was found to be the best with good correlation for the $Fe^0$ and Aw/Fe system. However, for the Pd/Fe system, the experimental data were evaluated to be well fitted to the second-order kinetic model. The reaction rate constants (k) were in the order of Pd/Fe > Aw/Fe > $Fe^0$, with the rate constant of Pd/Fe being much higher than that of the other two reductants.

• 펄프종이기술
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• 제33권1호
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• pp.73-79
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• 2001

Stricter environmental demands have increased the need to replace conventional C/D bleaching sequence by chlorine-free sequence. Permanganate is well known as a powerful oxidant and have been used industrially in variable fields. However, it has considered to be difficult to use permanganate as a bleaching reagent because of its strong oxidative effect decreasing the viscosity of pulps extremely. We have tried to use permanganate as a bleaching reagent for KP under the mild condition and it was clear that pernanganate oxidized lignin remained in pulps selectively and increased pulp brightness decreasing K number of pulps with small degradation of cellulose. We have employed the neutral condition in the permanganate bleaching process in this study. In this case, permanganate was converted to manganese dioxide after bleaching reaction. The manganese dioxide is remained in the treated pulp fibers because of its insolublity in water. So it was required to reduction the manganese oxide to manganese ion by using reductants with acid. In this paper, we proposed to use oxalic acid as a reducing reagent converting manganese oxide to manganese ion after bleaching reaction. Oxalic acid plays the role as a reductant and a acid, so post-treatment after bleaching became to be easy by using oxalic acid. On the study using lignin model compounds, it was clear that permaganate react with phenols firstly, after that oxalic acid reduce the manganese oxide to manganese ion in the mixture of permanganate, phenols and oxalic acid. Several lignin model compounds ($\textit{p}$-hydroxybenzaldehyde, vanillin, syringaldehyde, veratraldehyde) are selected to elucidate the effect of substituents on reaction rate and its mechanism with permanganate including oxalic acid in this study. Except for veratraldehyde, the rate of oxidative degradation of phenolic compounds by permanganate with oxalic acid are higher than neutral condition. Especially, the degradation rate of $\textit{p}$-hydroxybenzaldehyde are strongly dependent on pH of reaction mixture. On the other hand, the degradation rate of veratraldehyde are decreased with decreasing pH and main degradation product is veratric acid. This result indicate that pH of bleaching liquor should be kept over 2 to degrade of non-phenolic lignin in the pulps effectively in permanganate bleaching.

• 한국자원식물학회지
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• 제33권4호
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• pp.271-278
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• 2020

이상의 연구 결과로 먹넌출 열매 추출물은 GSK3β 의존성 Cyclin D1 단백질의 분해를 통해 대장암세포의 생육 억제와 관련이 있는 것으로 확인된다. 본 결과는 대장암의 항암제 개발을 위한 소재로 먹넌출 열매의 활용이 가능할 것으로 판단된다.

• Journal of the Korean Wood Science and Technology
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• 제43권3호
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• pp.344-354
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• 2015

이온성 액체를 이용한 거대억새의 전처리 특성을 알아보기 위하여 1-ethyl-3-methylimidazolium acetate ([Emim][OAc])와 1-butyl-3-methylimidazolium acetate ([Bmim][OAc]) 두 종류의 이온성 액체로 $90^{\circ}C$, $110^{\circ}C$, $130^{\circ}C$ 세 온도조건에서 전처리를 진행하였다. 반응 온도가 높아짐에 따라 cellulose-rich product (CP)의 수율은 87.2%에서 67.6%로 점차 감소하였으며 ionic liquid lignin (ILL)의 수율은 2.2%에서 9.9%로 증가하였다. CP는 ILL에 비해 탄소함량은 낮았지만, 산소함량은 높게 나타났다. CP의 효소당화 결과 $110^{\circ}C$에서 [Emim][OAc]로 전처리하여 얻은 CP의 당화율이 56.7%로 가장 높게 나타났다. ILL의 열중량 분석 결과에 의하면 전처리 온도가 증가함에 따라 최대분해율은 점차 감소하였으며, 최대분해온도는 [Emim][OAc]로 처리한 ILL이 $274{\sim}279^{\circ}C$로 [Bmim][OAc]의 $2701{\sim}294^{\circ}C$보다 낮은 경향을 나타내었다. 전처리 온도가 $90^{\circ}C$에서 $130^{\circ}C$로 증가함에 따라 ILL 내 ${\beta}$-O-4 결합빈도는 [Emim][OAc]의 경우 $2315{\mu}mol/g$에서 $591{\mu}mol/g$으로, [Bmim][OAc]의 경우 $1936{\mu}mol/g$에서 $2478{\mu}mol/g$으로 감소하였다. ILL의 S/G ratio는 [Bmim][OAc]용액으로 $110^{\circ}C$에서 처리하였을 때 1.2로 가장 높게 나타났다.