• Korean Chemical Engineering Research
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• 제54권5호
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• pp.698-705
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• 2016

부틸 아세테이트는 반응증류탑에서 초산과 부탄올의 에스테르 교환반응에 의해 제조된다. 기존의 반응증류 공정은 생성물인 부틸 아세테이트가 내부 공비첨가제로 사용되는데, 이 경우 부틸 아세테이트가 물과 함께 탑상으로 제거된 후 상 분리를 거쳐 반응증류탑으로 환류된다. 이는 생성물인 부틸 아세테이트가 반응영역에 많이 분포하게 하여 반응의 평형 전환율이 낮아지고 이에 따라 생성물의 수율이 저하되는 단점이 있다. 이러한 문제를 외부 공비첨가제를 사용하여 해결하였다. 외부 공비첨가제는 물과 새로운 공비를 형성하여 기존 공정에 비해 탑의 반응영역에서 부틸 아세테이트의 농도를 낮게한다. 본 연구에서는 싸이클로헥산을 외부 공비첨가제로 사용하였을 때와 내부 공비첨가제를 사용하였을 때 부틸 아세테이트의 수율과 생성 속도를 실험과 모사를 통하여 비교하였다. 이를 위하여 파일럿 규모의 반응증류탑으로 실험을 진행하였으며, 실험 및 모사 결과를 통하여 외부 공비첨가제를 사용한 공정이 내부 공비첨가제를 사용한 경우보다 같은 에너지에서 보다 높은 부틸 아세테이트 수율을 나타냄을 보였다.

• 대한한의학회지
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• 제20권2호
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• pp.108-120
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• 1999

In this study, body weight levels of glucose, insulin and triglyceride in blood and glucosidase activity of the small intestine were investigated to determine the effect of Sangbaegpitang and Supungsungiwhan on the glucose metabolism of db/db mice. The GLUT4 mRNA of muscle tissue and the Acetyl CoA Carboxylase and the activation rate of GLUT2 mRNA of liver tissue were measured by the reverse transcription-polymerase chain reaction method and by the vitro transcription. The results were obtained as follows: 1. In the Sangbaegpitang administration group, (1) The level of triglyceride was decreased significantly and the glucosidase activity of the small intestine was inhibited remarkably, (2) The amounts of the GLUT4 mRNA in muscle tissue and Acetyl CoA Carboxylase mRNA in liver tissue were increased significantly. (3) Though glucose level in both fasting and non-fasting, were decreased and the insulin level in blood was increased, the results showed no statistical significance. 2. In the Supungsungiwhan administration group, (1) The levels of glucose and triglyceride were decreased significantly in the blood of non-fasting animals. (2) The glucosidase activity of small intestine was inhibited markedly and the amounts of GLUT4 mRNA of muscle tissue and GLUT2 mRNA of liver tissue were increased significantly. (3) The glucose levels in the fasting group were reduced, while insulin level was increased but showed no statistical significance, Based on the above results, our conclusions are as follows: Sangbaegpitang & Supungsungiwhan are thought to be capable of inhibiting the activity glucosidase, the enzyme which influences carbohydrate metabolism in the small intestine of db/db mice(the experimental diabetic model) and delaying the absorption of carbohydrate, thus proving effective on inhibiting the increase of non-fasting glucose level effectively. Futhermore Sangbaegpitang and Supungsungiwhan are though: to be capable of preventing the composition of free fatty acids by restoring the production of GLUT4 mRNA of muscle tissues and GLUT2 mRNA of liver tissues. Those results suggests that above prescriptions can be applied to non-insulin dependent diabetes mellitus in order to improve insulin resistance.

• 한국추진공학회:학술대회논문집
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• 한국추진공학회 2011년도 제36회 춘계학술대회논문집
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• pp.1-2
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• 2011

Hybrid rockets have lately attracted attention as a strong candidate of small, low cost, safe and reliable launch vehicles. A significant topic is that the first commercially sponsored space ship, SpaceShipOne vehicle chose a hybrid rocket. The main factors for the choice were safety of operation, system cost, quick turnaround, and thrust termination. In Japan, five universities including Hokkaido University and three private companies organized "Hybrid Rocket Research Group" from 1998 to 2002. Their main purpose was to downsize the cost and scale of rocket experiments. In 2002, UNISEC (University Space Engineering Consortium) and HASTIC (Hokkaido Aerospace Science and Technology Incubation Center) took over the educational and R&D rocket activities respectively and the research group dissolved. In 2008, JAXA/ISAS and eleven universities formed "Hybrid Rocket Research Working Group" as a subcommittee of the Steering Committee for Space Engineering in ISAS. Their goal is to demonstrate technical feasibility of lowcost and high frequency launches of nano/micro satellites into sun-synchronous orbits. Hybrid rockets use a combination of solid and liquid propellants. Usually the fuel is in a solid phase. A serious problem of hybrid rockets is the low regression rate of the solid fuel. In single port hybrids the low regression rate below 1 mm/s causes large L/D exceeding a hundred and small fuel loading ratio falling below 0.3. Multi-port hybrids are a typical solution to solve this problem. However, this solution is not the mainstream in Japan. Another approach is to use high regression rate fuels. For example, a fuel regression rate of 4 mm/s decreases L/D to around 10 and increases the loading ratio to around 0.75. Liquefying fuels such as paraffins are strong candidates for high regression fuels and subject of active research in Japan too. Nakagawa et al. in Tokai University employed EVA (Ethylene Vinyl Acetate) to modify viscosity of paraffin based fuels and investigated the effect of viscosity on regression rates. Wada et al. in Akita University employed LTP (Low melting ThermoPlastic) as another candidate of liquefying fuels and demonstrated high regression rates comparable to paraffin fuels. Hori et al. in JAXA/ISAS employed glycidylazide-poly(ethylene glycol) (GAP-PEG) copolymers as high regression rate fuels and modified the combustion characteristics by changing the PEG mixing ratio. Regression rate improvement by changing internal ballistics is another stream of research. The author proposed a new fuel configuration named "CAMUI" in 1998. CAMUI comes from an abbreviation of "cascaded multistage impinging-jet" meaning the distinctive flow field. A CAMUI type fuel grain consists of several cylindrical fuel blocks with two ports in axial direction. The port alignment shifts 90 degrees with each other to make jets out of ports impinge on the upstream end face of the downstream fuel block, resulting in intense heat transfer to the fuel. Yuasa et al. in Tokyo Metropolitan University employed swirling injection method and improved regression rates more than three times higher. However, regression rate distribution along the axis is not uniform due to the decay of the swirl strength. Aso et al. in Kyushu University employed multi-swirl injection to solve this problem. Combinations of swirling injection and paraffin based fuel have been tried and some results show very high regression rates exceeding ten times of conventional one. High fuel regression rates by new fuel, new internal ballistics, or combination of them require faster fuel-oxidizer mixing to maintain combustion efficiency. Nakagawa et al. succeeded to improve combustion efficiency of a paraffin-based fuel from 77% to 96% by a baffle plate. Another effective approach some researchers are trying is to use an aft-chamber to increase residence time. Better understanding of the new flow fields is necessary to reveal basic mechanisms of regression enhancement. Yuasa et al. visualized the combustion field in a swirling injection type motor. Nakagawa et al. observed boundary layer combustion of wax-based fuels. To understand detailed flow structures in swirling flow type hybrids, Sawada et al. (Tohoku Univ.), Teramoto et al. (Univ. of Tokyo), Shimada et al. (ISAS), and Tsuboi et al. (Kyushu Inst. Tech.) are trying to simulate the flow field numerically. Main challenges are turbulent reaction, stiffness due to low Mach number flow, fuel regression model, and other non-steady phenomena. Oshima et al. in Hokkaido University simulated CAMUI type flow fields and discussed correspondence relation between regression distribution of a burning surface and the vortex structure over the surface.

• Tuberculosis and Respiratory Diseases
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• 제46권2호
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• pp.195-203
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• 1999

연구배경: 염색체의 안전성을 유지시켜 주며 DNA 복제의 완성에 필수적인 역할을 하는 telomere는 RNA를 포함하는 핵 단백질 복합체인 telomerase에 의해 반복 서열을 덧붙임으로써 안정화 되고, 이러한 telomere 의 안정화에 의해 세포들은 불멸성을 획득하게 된다. 폐암에서 telomerase의 활성이 조기에, 높은 빈도에서 검출됨이 여러 연구에서 확인된 바 있다. 본 연구는 조직학적으로 확진된 소세포암 및 비소세포암 환자들을 대상으로 기관지 내시경적 생검 조직으로 telomerase 활성을 측정함으로써 폐암에 있어서 telomerase 활성이 악성 종양의 유용한 지표가 되는지 확인함과 동시에 기관지 내시경 생검의 telomerase 활성 검출의 유용성을 평가하고자 하였다. 방 법: 폐암으로 추정되어 내시경적 생검사 동시에 채취한 조직 중 조직학적 진단이 이루어진 폐암 33례를 대상으로 하였다. Polymerase chain reaction에 기초한 TRAP assay를 이용하여 telomerase 활성을 측정하였다. 결 과: 총 33례의 폐암 조직 중 28례에서 telomerase 활성 양성을 보였다. 비소세포암에 있어서 telomerase 활성은 85%(27례 중 23례)에서 양성을 보였고, 소세포암에 있어서는 83%(6례 중 5례)에서 양성을 보였다. 소세포암 중 l례, 비소세포암 중 4례에서 telomerase 활성이 검출되지 않았다. 폐암 조직에서 검체간에 telomerase 활성의 정도는 다양하였다. Telomerase 활성은 임상 병기 II 에서 50% 에서 양성을 보였고, III에서 93%에서 양성을 보였고, IV에서는 100%에서 양성을 보였다. 임상 병기 III 이나 IV의 경우 임상 병기 II에 비해 telomerase 활성 양성률이 의미있게 높았다(p<0.05). 결 론: 소세포암 및 비소세포암 모두에서 telomerase가 활성화 되어 있음을 확인 할 수 있었고, 수술적 절제나 세포주 배양을 통해 얻어진 조직을 이용한 이전의 연구와 비교하였을 때, 기관지 내 병변을 가진 폐암에서 기관지 내시경적 생검 조직에서 telomerase 활성 검출이 유용성을 가질 수 있음을 확인 할 수 있었다. 폐암에 있어서 진행된 병기에서 조기의 폐암에 비해 telomerase 양성률이 더 높음을 확인할 수 있었다.

• Asian-Australasian Journal of Animal Sciences
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• 제19권9호
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• pp.1257-1261
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• 2006

Pleiomorphic adenoma gene-like1 (PLAGL1) encodes a zinc-finger (ZF) protein with seven ZFs of the C2H2-type which is a regulator of apoptosis and cell cycle arrest, and also regulates the secretion of insulin. In both human and mouse, PLAGL1 is a candidate gene for tumor suppressor and transient neonatal diabetes mellitus (TNDM). In this study, a 2,238 bp fragment covering the complete coding region was obtained and deposited to GenBank (accession number: DQ288899). The reverse transcriptase-polymerase chain reaction (RT-PCR) indicated that PLAGL1 was expressed almost equally in heart, liver, spleen, lung, kidney, stomach, small intestine, skeletal muscle, fat, uterus and ovary. Comparing the sequences of Large White and Meishan pigs, a C-T transition in exon 6 was found. The polymorphism could be detected by TaqI and was genotyped in five purebreds (Large White, Landrace, Meishan, Tongcheng and Bamei). Association analysis was performed between the polymorphism and carcass traits in 276 pigs of a "Large White${\times}$Meishan" F2 resource population. As a consequence, significant associations of the genotypes with shoulder backfat thickness (SFT) and internal fat rate (IFR) were observed. Pigs with TT genotype had low SFT and high IFR compared with TC or CC genotypes.

• 한국수산과학회지
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• 제42권1호
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• pp.15-19
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• 2009

A simple and sensitive method for erythromycin quantification by liquid chromatography electrospray mass spectrometry (LC-MS/MS) in fishery products was developed. Samples were extracted by liquid-liquid extraction using 70% acetonitrile. Lipids were removed by acetonitrile saturated hexane. LC separation was performed on a Shiseido UG C-18 column ($150\;mm{\times}2.0\;mm$ internal diameter.) with a gradient system of 0.2% acetic acid-acetonitrile containing 0.2% acetic acid as a mobile phase at flow rate of 0.2 mL/min. The mass spectrometer was operated in selected reaction monitoring with positive electro-spray interface. Transitions were monitored a m/z $734{\to}577$ and $734{\to}158$, with m/z $734{\to}577$ chosen for quantification. Recovery of erythromycin from fish and shrimp fortified at the 10 ng/mL, 50 ng/mL and 100 ng/mL were 91.6-109.4%, 84.4-111.2% and 98.8-109.6% with high precision, respectively. Limits of quantification and limits of detection of erythromycin in both fish and shrimp were 10.0 ng/mL and 1.0 ng/mL, respectively. This analysis method for erythromycin has been proposed for registration in the Korean Official Methods of Food Analysis and has been utilized for fishery products analysis by the Korea Food and Drug Adminstration and the National Fisheries Products Quality Inspection Service.

• 한국동물위생학회지
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• 제14권1호
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• pp.19-26
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• 1991

A considerably high rate of abnormal deliveries of unknown etiology was observed among dairy cattles from November 1988 to February 1989 and Korean native tattles from January to April 1990. The abnormal deliveries consisted of abortions, stillbirths and calf deformities refers to as congenital arthrogryposis hydranencephaly (AH )syndrome. In order to know the level of Akabane antibody of dairy cattle raised in Kyungbuk province, serum neutralization test was conducted with Akabane virus(OBE-1 strain) and HmLu(Hamster lung) cell line. The results were summarized as follows. 1. During 4 months(Nov. 1988-Feb. 1989), abortion (3 heads), stillbirth(1 head) and congenital abnormalities(13 heads) of newborn were occurred in 17 dairy cattles raised in Kyungbuk province. 2. During 4 months(Jan.-Apr.1990), stillbirth(2 heads) and congenital deformities (13 heads) of newborn were occurred in 15 Korean native tattles raised in Kyungbuk province. 3. In Fev, and Apr. 1990, 1,005 dairy cattles at 99 farms were investigated on the actual condition of possessing Akabane antibody. The result was that 1,000 heads (99.9%) in 1,005 dairy cattles reacted as positive condition in Akahane antibody. The antibody titer was from 4 to over 256. 4. 189 heads (18.8%) of 1,005 dairy cattles werw below antibody titer 8 and 816 heads (81.2%) were over 16. 5. Akabane antibody titer of east coast legions(Pohang Yeongil etc) was all over 16, that of internal legions (Yeongiu, Andong. etc) was relatively low, The result suggest that the vaccination for Akabane disease will be unnecessary for the time being because of possessing higher antibody titer reaction except the newly introduced cattle and Akabane virus was widely disseminated in kyungbuk province during the summer months in 1987 or 1988.

• 한국결정성장학회지
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• 제30권4호
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• pp.123-130
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• 2020

AGM 연축전지(Absorbent Glass Mat Lead-Acid Battery)의 수명 특성을 결정짓는 양극 활물질(Active Material)의 주요 구성 결정인 4BS(Tetrabasic lead Sulfate)의 입자 크기를 제어하기 위해 4BS Nano Seed(NS)를 적용 중에 있다. 4BS NS 적용 시, 나노 입자 특성상 분산 안정성이 저하되어 제 기능을 다하지 못한다. 이를 개선하기 위해 기존 첨가제인 광명단(Red Lead)에 나노 입자의 4BS seed가 포함된 Incorporated Nano Seed(INS)를 함량별로 첨가하여 양극판 분석과 제품 성능을 평가하였다. INS 함량이 증가할수록 4BS 입자 크기는 작아지면서 균일해지는 특성을 확인할 수 있었으며, 반응 비표면적 증가에 따른 고율 방전 특성도 향상되는 것을 알 수 있었다. 극판 제조 공정에서의 개별 극판에 대한 입도 분포의 편차를 확인하기 위해, AGM 연축전지 200 대 대한 내부 저항 및 전압 검사를 진행하였으며 제품 제조 공정 품질 편차가 감소하는 것을 확인하였다.

• 한국자동차공학회논문집
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• 제14권3호
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• pp.178-185
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• 2006

This paper investigates the steady-state combustion characteristics of the Homogeneous charge compression ignition(HCCI) engine with variable valve timing(VVT) and dimethyl ether(DME) direct injection, to find out its benefits in exhaust gas emissions. HCCI combustion is an attractive way to lower carbon dioxide($CO_2$), nitrogen oxides(NOx) emission and to allow higher fuel conversion efficiency. However, HCCI engine has inherent problem of narrow operating range at high load due to high in-cylinder peak pressure and consequent noise. To overcome this problem, the control of combustion start and heat release rate is required. It is difficult to control the start of combustion because HCCI combustion phase is closely linked to chemical reaction during a compression stroke. The combination of VVT and DME direct injection was chosen as the most promising strategy to control the HCCI combustion phase in this study. Regular gasoline was injected at intake port as main fuel, while small amount of DME was also injected directly into the cylinder as an ignition promoter for the control of ignition timing. Different intake valve timings were tested for combustion phase control. Regular gasoline was tested for HCCI operation and emission characteristics with various engine conditions. With HCCI operation, ignition delay and rapid burning angle were successfully controlled by the amount of internal EGR that was determined with VVT. For best IMEP and low HC emission, DME should be injected during early compression stroke. IMEP was mainly affected by the DME injection timing, and quantities of fuel DME and gasoline. HC emission was mainly affected by both the amount of gasoline and the DME injection timing. NOx emission was lower than conventional SI engine at gasoline lean region. However, NOx emission was similar to that in the conventional SI engine at gasoline rich region. CO emission was affected by the amount of gasoline and DME.

• Journal of Advanced Marine Engineering and Technology
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• 제35권5호
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• pp.566-575
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• 2011

LPG 연료공급방식은 배출가스를 저감시킬 수 있는 유용한 시스템으로 연구가 지속적으로 진행되고 있다. LPG는 경유와 휘발유보다 높은 증기압과 낮은 점도와 표면장력을 유지하므로 고무류와 화학 반응에 따른 연료펌프의 기계적인 손상으로 내구성이 저하되고 있는 실정이다. 본 연구에서는 이러한 문제점을 해결하기 위해 LPLi 시스템에서 유지보수의 편리함과 가격경쟁을 위해 개발된 외장형 펌프를 사용하여 LPG 연료의 조성 및 온도에 따른 특성을 평가하고자 실험을 하였다. 그 결과로서, 내장형 펌프와 외장형 펌프의 성능차이는 거의 없으며 프로판 함유율이 높고, 연료온도가 높아짐에 따라 유량은 많아지나 펌프효율은 거의 차이가 없었다. 또한 LPG 자동차 연료공급장치의 특성상 연료조성 및 온도변화에 따른 차압도 거의 일정하게 나타내었다.