• Korean Chemical Engineering Research
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• v.54 no.5
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• pp.612-620
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• 2016

Aqueous mineral carbonation process, in which $CO_2$ is captured through the reaction with aqueous calcium oxide (CaO) solution, is one of CCU technology enabling the stable sequestration of $CO_2$ as well as economic value creation from its products. In order to enhance the carbon capture efficiency, it is required to maximize the dissolution rate of solid reactants, CaO. For this purpose, the proper design of a reactor, which can achieve the uniform distribution of solid reactants throughout the whole reactor, is essential. In this paper, the effect of internal reactor designs on the solid dispersion quality is studied by using CFD (computational fluid dynamics) techniques for the pilot-scale reactor which can handle 40 ton of $CO_2$ per day. Various combination cases consisting of different internal design variables, such as types, numbers, diameters, clearances and speed of impellers and length and width of baffles are analyzed for the stirred tank reactor with a fixed tank geometry. By conducting sensitivity analysis, we could distinguish critical variables and their impacts on solid distribution. At the same time, the reactor design which can produce solid distribution profile with a standard deviation value of 0.001 is proposed.

• Korean Chemical Engineering Research
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• v.54 no.5
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• pp.698-705
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• 2016

Butyl acetate is produced from acetic acid and butanol via an esterification reaction in reactive distillation (RD). The product, butyl acetate, has been used as an internal entrainer until now. In this case, butyl acetate and water are removed at the top of column and separated into two different phases (organic and aqueous phases) after condensation, and butyl acetate rich organic phase is refluxed into the RD. This method makes butyl acetate remain high at the reactive zone, leading to lower equilibrium conversion and product yield. We introduced an extraneous entrainer to solve the problem. The extraneous entrainer forms a new azeotrope with water. The proposed process provides lower concentration of butyl acetate in the reactive zone than conventional RD processes using an internal entrainer. We compared the yield and production rate of butyl acetate between the proposed and conventional processes through pilot-scale experiments. Experimental and simulation results showed that the proposed process was more efficient than conventional process using internal entrainer.

• The Journal of Korean Medicine
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• v.20 no.2
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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.

• Proceedings of the Korean Society of Propulsion Engineers Conference
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• 2011.04a
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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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• v.46 no.2
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• pp.195-203
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• 1999

Background: Telomerase enzyme activity is not detected in most normal cells, a phonomenon believed to be associated with limitations on cellular proliferation. Since this activity is detected in nearly all human tumor, including lung cancers, it has been suggested that telomerase activation may be coupled to acquisition of malignant phenotype. In this study, we determined whether telomerase activity was associated with tumor pathologic stage. Methods: Primary tumor specimens obtained by bronchoscopic biopsies from 33 patients were analyzed. Telomerase activity was measured by means of a modified Telomeric Repeat Amplication Protocol(TRAP) assay. Results: Telomerase activity was detected in 23 of the 27 non-small-cell lung cancer and 5 of 6 small-cell lung cancer. A few primary tumors did not appear to have detectable telomerase activity. Positive associations were found between the telomerase-positive rate and tumor stage(p<0.05). Conclusion: High telomerase activity is detected frequently in primary lung cancers that exhibit high tumor cell proliferation rates and advanced pathologic stage.

• Asian-Australasian Journal of Animal Sciences
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• v.19 no.9
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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.

• Korean Journal of Fisheries and Aquatic Sciences
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• v.42 no.1
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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.

• Korean Journal of Veterinary Service
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• v.14 no.1
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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.

• Journal of the Korean Crystal Growth and Crystal Technology
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• v.30 no.4
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• pp.123-130
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• 2020

Nano seed incorporated in micro-sized 4BS (Tetrabasic lead Sulfate) seed was applied to the positive electrode active material and compared with Nano 4BS seed (NS). The dispersion of NS decreased due to the aggregation phenomenon, while the nano seed incorporated in micro-sized 4BS seed (INS) could confirm excellent dispersion. As the content of INS increased, the particle size of the active material became small and constant, which was confirmed through SEM and particle size analysis. The specific surface area for the reaction was increased and the high-rate discharge and lifetime characteristics were improved. In order to confirm the variation in particle size distribution in the plate manufacturing process, internal resistance and voltage were measured for 200 AGM lead-acid batteries, and it was confirmed that batteries quality variation decreased.

• Transactions of the Korean Society of Automotive Engineers
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• v.14 no.3
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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.