The biodiesel production characteristics in a pulsed-corona plasma reactor has been investigated through parametric tests. Transesterification of rapeseed oil together with camelina oil was done with the change of such variables as voltage of power, molar ratio, KOH catalyst and temperature. The energetic electrons emitted from pulsed-corona plasma has contributed to the enhancement of yield on rapeseed oil in short time (15 min). The higher yield on camelina oil was observed in 5 min. The optimal parameters were shown as the voltage of 23 kV, the molar ratio of 5/1, the content of KOH catalyst of 0.6 wt% and the temperature of 28℃ under the rotating rate of spark gap of 900 rpm.
Catharanthus roseus로부터 생산되는 빈카알칼로이드는 암을 치료하는 데에 사용되는 가장 중요한 천연물 중의 하나이다. 이러한 항암제는 두 단량체 인돌 알칼로이드인 catharanthine과 vindoline의 결합으로 합성될 수 있다. 이 중 vindoline의 생합성에 관계하는 경로를 조사하기 위해서 tabersonine의 메틸기에 중수소를 치환한 전구체인 tabersonine-CD3 1a를 합성하였다. 이는 중수소의 질량 증가로 인해 자연에서 발생하는 tabersonine과 뚜렷이 구별될 수 있도록 해 준다. 우리는 이 중소소가 치환된 tabersonine 1a가 성공적으로 vindoline 생합성경로에 편입되어 중수소가 치환된 3개의 새로운 vindoline 중간체(2a, 3a와 4a)를 생성함을 보였다. 세포현탁배양액에 tabersonine-CD3 1a를 주입한 5일과 13일째에 생성된 대사물인 16-Hydroxytabersonine-CD3 (m/z 356) 2a, 16-Methoxytabersonine-CD3 (m/z 370) 3a와 16-Methoxy-2,3-dihydro-3- hydroxytabersonine-CD3 (m/z 388) 4a의 생성량을 UPLC/MS를 사용하여 측정하였다. 출발물 1a에서 생성물 2a, 그리고 2a에서 3a로의 전환은 빨랐던 반면 3a에서 4a로의 전환은 상대적으로 훨씬 느렸다. 따라서 각 대사물들의 상대적 전환속도를 서로 비교해 보았을 때 vindoline 생합성 과정의 첫 세 단계 중에서 가장 느린 마지막 단계가 속도결정단계임을 암시한다. 즉 대사물 3a에서 4a로의 느린 전환속도의 결과, 배양 후 13일까지도 3a의 축적률이 현저히 증가됨을 보였다. 배양 5일째의 대사물 2a, 3a와 4a의 축적비는 각각 1, 2와 0.1이었다. 그러나 desacetoxyvindoline-CD3 5a, deacetylvindoline-CD3 6a와 vindoline-CD3 7a의 피크는 배양 13일 후에도 발견되지 않아 세포현탁 배양액에 각 생합성단계와 관련된 효소들이 존재하지 않음을 알 수 있었다.
자성유체 유체씰에 사용할 수 있는 마그네타이트를 공침법에 의하여 합성하였다. 마그네타이트의 평균입자크기는 동적광산란 측정장치(DLS)에 의해 약 10-12 nm 로 측정되었다. XRD 측정결과, NH4OH 의 농도가 증가함에 따라 마그네타이트의 결정화도가 증가하였다. 수중 분산된 자성유체의 제타전위는 -49.3 mV 에서 -26.2 mV 까지 DLS에 의하여 측정되었다. 입자의 형상은 구형이었고, 수상과 유상 자성유체에서 스파이킹 효과를 확인하였다.
본 실험에서는 투명비누를 만드는데 사용되는 폴리올의 최적 농도를 실험계획법을 이용하여 결정하였다. 짧은 사슬을 보유한 디프로필렌글리콜과 1,3 부틸렌글리콜은 비누의 투명도를 증가시켰으나 폴리에틸렌글리콜 400, 글리세린과 디글리세린은 비누를 불투명하게 하였다. 프로필렌글리콜, 디글리세린, 디프로필렌글리콜 및 폴리에틸렌글리콜의 농도를 증가시키면 비누의 경도는 증가하였다. 경도, 투명도, 물의 흡수성 및 마찰 용해도는 디프로필렌글리콜, 폴리에틸렌글리콜, 설탕과 트리에탄올아민의 농도를 조절하여 최적화할 수 있었다.
유화제만을 사용하는 것 보다 더 좋은 유화특성을 갖는 유화보조제에 관한 연구이다. 그 화합물들은 숙신산과 프로필렌글리콜과의 에스테르화 반응에 의하여 합성되었다. 그 구조는 FT-IR과 1H-NMR 분석으로 확인하였다. 표면장력, 임계미셀농도(cmc), 유화력 등 계면특성을 각각 주어진 조건하에서 시험하였다. 그 수용액의 표면장력은 33-35 dyne/cm 이었고, cmc는 표면장력법에 의하여 산정하였다. 그리고, 유화력은 호호바오일의 경우 우수하였다. 결과적으로 합성한 디프로필렌글리콜 숙시네이트는 O/W 유화에서의 유화보조제로서 응용이 기대된다.
In vivo nicotine is associated with Alzheimer's, Parkinson's and lung cancer. Diagnostic assays of these diseases depend on very low analytical detection limits. In this study, a sensitive analytical method was examined using a voltammetric graphite pencil electrode (GPE) and a modified carbon nanotube paste electrode (CNE). The optimum analytical conditions for both electrodes were compared using square wave anodic stripping voltammetry (SW) and cyclic voltammetry (CV) obtaining 400 sec accumulation time and oxidation peak. Under optimum parameters, the stripping working range of GPE was 5.0-40.0μg/L, CNE: 0.1-0.8 and 5-50μg/L. Quantification limits were 5.0μg/L for GPE and 0.1μg/L for CNE, while detection limits were 0.6μg/L for GPE and 0.07μg/L for CNE. A standard deviation of 10.0μg/L was observed for 0.064 GPE and 0.095 CNE (n = 12) using 400 sec accumulation time. The results obtained can be applied to non.treated urine and ex vivo biological diagnostics.
A numerical simulation of plume from a stack into atmospheric cross flow is investigated using a two-dimension model. The simulation is based on the k~ε turbulence model and a finite volume method. In this paper, it mostly researches how the wind velocity affects the flue gas diffusion from an 80 m high stack. Wind velocity is one of the most important factors for flue gas diffusion. The plume shape size, the injection height, the NO pollutant distribution and the concentration at the near ground are presented with two kinds of wind velocities, 1 m/s and 5 m/s. It is found that large wind velocity is better for flue gas diffusion, it generates less downwash. Although the rise height is lower, the pollutant dilutes faster and more sufficient.
가교에 관한 리뷰논문으로 특허의 다수는 의료용이다. 조직공학용 지지체나 약물전달용 매체로 쓰이는 고분자의 가교는 세포 무독성, 제 자리 겔 형성성이 있는 가교반응을 중시하고 있다. 가교를 탄성률, 내약품성, 내열성의 증대 목적 외에 가교부위에 금속 흡착성, 방오성, 항균성, 이온교환성 등의 기능을 부여하고 있다. 환경의 자극에 응답하는 스마트 가교, 환경을 고려한 광 가교, 물리적 가교, 효소가교, 천연물 가교, 수성가교가 연구되고 있다. 120세 수명을 목표로 의용재료의 발전에 고분자 소재의 개발도 필수적이다. 가교를 통한 고분자의 기능성 부여 및 물성 강화도 더욱 섬세하게 될 것이다. 고분자 가교물 중의 중요한 분야를 점하는 히드로젤은 주사용 제자리 겔 형성성의 개선 방향으로 전개될 것이다. 코팅용 고분자 가교제는 작업자, 작업환경을 고려하여 저독성-무독성의 가교제, 낮은 에너지에서 가교되는 에너지 절약형 가교제가 개발될 것이다.
금속 주조시 사용되는 탄소이형제를 카본블랙과 점증제 겸 알데하이드 화합물의 경화제로 사용될 수 있는 수용성 고분자인 잔탄검(X-gum), 카르복시메틸셀룰로오스(CMC)을 혼합하여 제조하였다. 이 때 카본블랙의 안정한 분산을 위하여 0.25 wt%의 X-gum 또는 1.0 wt%의 CMC가 적당하였다. 1.0 wt% 보다 낮은 농도의 CMC를 사용했을 경우 카본블랙이 매우 쉽게 층분리되었다. 유리판에 대한 부착력은 경화제와, 구르탈알데하이드 및 사슬연장제인 올리고당의 양에 비례하였으며. X-gum으로 제조된 탄소 이형제는 CMC를 이용해 제조된 것보다 유리에 대한 부착력이 우수하였다. 결과적으로 본 실험의 최적 조건에서 제조된 탄소이형제는 친환경적으로 주조시에 적용할 수 있을 것으로 판단된다.
본 논문은 다양한 시설내에 적은 농도의 CO2 제거를 위한 선택적 CO2 흡수능력을 향상시킨 흡착제의 효율평가에 관한 것이다. 직경 4mm의 구형 흡착제는 시판용 제올라이트에 첨가제, 물, 바인더, LiOH를 섞어 제조하였다. 칼럼테스트에서 400분 이내에 90% 이상의 CO2흡착효율을 나타내었고, 흡착필터모듈 흡착능력을 평가하기 위해 회분식과 연속식타입의 챔버테스트가 시행되었다. 회분식테스트에서 30분 이내에 약 92%의 CO2가 제거되는 것을 확인하였다. 연속식테스트에서 30분 이내 70%의 CO2가 제거효율을 보였으며, 2,500ppm 이상의 CO2가 제거되는 것을 확인하였다. 재현성테스트를 수차례 수행한 결과 15일동안 1,000ppm 이상의 CO2가 연속적으로 제거됨을 보였다. TGA 분석법을 이용한 흡착량 분석에서 흡착제 g당 5.0mmol의 CO2를 흡착하는 것으로 나타났다. 본 연구에서 개발된 흡착제는 상온에서 저농도 CO2 실내환경에 적용가능한 것으로 판단된다.
Squid ink was added to the low salt fermented squid by 4% of concentration and ripened at 10℃ for 6 weeks and at 20℃ for 28 days. The effect of the squid ink on the titrable acidity and free amino acids of low salt fermented squid were investigated. The results are as follows; The titrable acidity in the salt fermented squid without addition of the squid ink was continuously decreased except for the salt fermented squid with 9% salt content till the latter stage of the ripening, had larger decreasing range than treatment groups. Seeing the composition of free amino acid, the major amino acids are proline, arginine, glutamic acid. leucine and glycine.
Hydrotreated biodiesel(HBD) is paraffinic bio-based liquid, with the chemical structure CnH2n+2, originating from vegetable oil(the process can also be applied to animal fat). The oil or fat is treated in a number of process, the most important being hydrogenation, in order to create a bio-based liquid diesel fuel. During the hydrogenation, oxygen is removed from the triglyceride and converted into water. Propane is formed as a by product and can be combusted and used for energy production. HBD can be used in conventional diesel engines, pure or blended with conventional diesel, due to its similar physical properties to diesel. This study reports the quality characteristics with chemical and physical properties as an alternative diesel fuel. Especially, HBD showed higher cetane value and number than FAME, and it is consisted of C15 - C18 n-paraffinic compounds. We also describes quality characteristics of HBD blends(2, 5, 10, 20, 30, 40, 50 vol%) in automotive diesel. HBD blends(max. 20 vol%) were the limit by the Korean specification due to poor low temperature characteristics.
A voltammetric assay of phenol ions was investigated using three electrode systems of graphite pencil working, reference and counter electrodes. Under optimum analytical parameters, square wave stripping working ranges were attained at a mili range of 10~80 mg/L and a micro range of 20~90 ug/L using seawater electrolyte. The developed sensor was applied to tap water and the human body system of a smoker. It was found that the methods can be applied to in vivo fluid or medicinal diagnosis.
Polymer electrolyte membrane fuel cell (PEMFC) performance degrade when sulfur dioxide is present in the fuel hydrogen gas, this is referred as SO2 poisoning. This paper reveals SO2 poisoning on PEMFC cathode part by measuring electrical performance of single cell under 1 ppm and 5 ppm on SO2 gas operating. The security of SO2 poisoning depended on SO2 concentration under the best operating conditions(65℃ of cell temperature and 100% of relative humidity between anode and cathode). SO2 adsorption occured on the surface of catalyst layer on membrane electrode assembly (MEA), In addition, MEA poisoning by SO2 was cumulative but reversible. After poisoning within 5 ppm SO2 for 1hr, the electrical performance of PEMFC was found to recover up to about 93% by cyclic voltametry scan.
N-(fluorodichlomethylthio) phthalimide-silver complexes were prepared and investigated the antimicrobial activity on rubber mat manufactured with waste rubber. We are exposed to harmful bacteria and fungi all the time. We manufactured antimicrobial mat to be imposed to mats that it can prevent generation of bacteria and microorganisms, and restrict their reproduction. Infection of medical devices causes significant morbidity and mortality. For aim of this study, we measured the antimicrobial mat manufactured with N-(fluorodichlomethylthio) phthalimide-Ag complex by CCD, FT-IR and NMR. The effect of mole ratio of N-(fluorodichlomethylthio) phthalimide-Ag complex on antibacterial activity to bacteria and fungi is investigated. Reduction rate is evaluated using the Quinn method. Escherichia Coli is effectively inhibited than Staphylococcus aureus by antimicrobial mat.
In this study, the antioxidative effects and inhibitory effects on tyrosinase and elastase of Sorbus commixta (S. commixta) twig extracts were investigated. The aglycone fraction of S. commixta twig extract showed the prominent free radical (1,1-diphenyl-2-picrylhydrazyl, DPPH) scavenging activity(FSC50, 13μg/mL). Reactive oxygen species (ROS) scavenging activities of S. commixta twig extracts on ROS generated in Fe3+-EDTA/H2O2 system were investigated by the luminol-dependent chemiluminescence assay. The 50 % ethanol extract among extracts showed the most prominent ROS scavenging activity (OSC50, 0.189μg/mL). The cellular protective effects of extract/fractions of S. commixta twig on the rose-bengal sensitized photohemolysis of human erythrocytes were investigated. The 50 % ethanol extract and ethyl acetate fraction showed the cellular protective effects against ROS in a concentration dependent manner (5~50μg/mL). The inhibitory effect of S. commixta twig extract on tyrosinase was investigated to assess the whitening efficacy. The ethyl acetate (IC50, 113.2μg/mL) and aglycone fraction(IC50, 105.3μg/mL) on tyrosinase showed more remarkable inhibitory effect than arbutin(IC50, 226.88μg/mL), known as the whitening agent. The inhibitory effect of aglycone fraction (IC50, 6.9μg/mL) on elastase was simillar to quercetin(IC50, 6.1μg/mL), flavonoid known as reference compound. These results indicate that extract/fractions of S. commixta twig can function as antioxidants in biological systems, particularly skin exposed to UV radiation by scavenging 1O2 and other ROS, and protect cellular membranes against ROS. S. commixta twig extracts can be applicable to new functional cosmetics for anti-aging products.
It is known that the content of saturated fatty acids methyl ester (SFAME) affect the pour point of biodiesel at low temperature. In this study, biodiesel (BD) was produced from beef tallow (TAL) by alkali catalyst. To reduce the saturation in BD, acetone fractionation was applied. Besides, TAL was also solvent-fractionated to reduce the saturated fatty acid (SFA) content for further producing BD. With acetone, TAL or TAL methyl ester (5:1 v/w) were fractionated at 10, 0, -10, and -15℃, respectively. At -10℃, 17.35% of SFA was observed in fractionated TAL (liquid part, -10TAL) when 5:1 solvent ratio was used for 24 hr. Under the same condition, fractionated BD (liquid part, -10BD) showed SFA (33.14%) with 78wt % yield. Also, fractionation of BD with different concentration of crystallizer 209 (0.1, 0.5, and 1%) along with different time (2, 6, 12, and 24 hr.) was observed. The best condition for reducing the SFA was 0.5% of crystallizer 209 addition for 12 hr of fractionation time at -10℃, in which 30.14% of SFA content was observed in BD (liquid part). Among different crystallizer, ps 66 showed the least content of SFA content (23.28%) in BD after fractionation (-10℃ and 24 hr) with 0.5wt% addition.
Sesame oil is a simple pressed oil as unrefined oil. During manufacturing process of roasting-expression, benzo(a)pyrene[B(a)P] formed as a strong carcinogenic substance is cause a social problem. In manufacturing process of sesame oil, it had following the forming pathway of benzo(a)pyrene[B(a)P] as well as minimizing plan of B(a)P formation. Suitable roasting condition by roaster was during 15~20min at 220℃, B(a)P content in sesame oil was 1.35~1.57μg/kg. Between roasting temperature and/or roastingtime and forming amount of B(a)P was showed a linear correlation. As a point of view the turbidity and yield of final product, roasting process of the more regular level was required.
The average sulfur content of crude oil is 2.2%. Coal is about 0.3 to 4.0 percent of the sulfur gases or particles being discharged into the atmosphere through the chimney as 1 to 2% SO3(Sulfur trioxide) and about 95% of the SO2 is reported. SO3 gas, which has many different causes of, as the combustion of sulfur containing fuel during the air due to the excess SO2 gas is oxidized to SO3 gas. Sulfur trioxide emitted from high sulfur heavy oil fired boiler caused white plume in stack and high temperature and cold end corrosion of facilities. So, in order to control sulfur trioxide concentration of Fuel gas in boiler, various of additives are used in other foreign. They are injected to Fuel Oil and consumed in boiler and reduce ash and the conversion rate of sulfur trioxide. In domestic, MgO compounds are used as additives but the total volume of them are made from other foreign company. In this study, MgO compounds were developed with liquid MgO compounds and field application was accomplished. The effect of newly developed chemicals and process were nearly equal to foreign products. In Consequent, the chemicals and process produced by newly developed technology can be substituted for foreign products and reduce the cost of plant operation.
This surfactant can be used as a cosmetics and chemical dispersants. The variation of critical micelle concentration(CMC) with temperature for N-eicosyl pyridinium bromide over the range 40℃ to 60℃ has been measured by drop methods. Thermodynamic quantities for micellization of N-eicosyl pyridinium bromide in water have been calculated by polynominal equation.