• Journal of Life Science
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• v.21 no.2
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• pp.221-226
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• 2011

The gene encoding 4-$\alpha$-glucanotransferase (mgtA) from Thermotoga neapolitana was cloned and expressed in Escherichia coli in order to investigate whether this enzyme was capable of producing cycloamylose for industrial applications. MgtA was purified to homogeneity by HiTrap Q HP and Sephacryl S-200 HR column chromatographies. The size of the enzyme as determined by SDS-PAGE was about 52 kDa, which was in good agreement with its deduced molecular mass of 51.9 kDa. The optimal temperature and pH for the activity of the 4-$\alpha$-glucanotransferase was found to be $85^{\circ}C$ and 6.5, respectively. The enzyme hydrolyzed the 1,4-$\alpha$-glucosidic bonds in oligomeric 1,4-$\alpha$-glucans and transferred oligosaccharides (maltotriose being the shortest one) to acceptor maltodextrins. However, the enzymes had no activity against pullulan, glycogen, and other di- or trioligosaccharides with rare types of $\alpha$-bond. MgtA is distinguished from 4-$\alpha$-glucanotransferase from Thermotoga maritima in that it can convert maltotriose into maltooligosaccharides. The treatment of glucoamylase after the reaction of MgtA with maltotriose, maltotetraose, maltopentaose, or maltohexaose as sole substrate revealed that MgtA yielded linear maltooligosaccharides instead of cycloamylose.

• Journal of the Korean Society for Marine Environment & Energy
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• v.16 no.4
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• pp.255-262
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• 2013

The boltzmann equation is based on the particle distribution function while the Navire-Stokes equation based on the continuum theory. In order to simulate free surface flow, this paper used the Lattice Boltzmann Method of which is the discretized form. The detail study on the characteristics of the Lattice Boltzmann Method for the free surface simulation was investigated. The developed code was validated with the traditional dam breaking problem by tracking the front position of the water. A basic roles of density functions in the Lattice Boltzmann Method is discussed. To have an engineering applications, the simulation is also conducted the free surface behavior with an arbitrary wall geometry.

• The Journal of Korean Institute of Communications and Information Sciences
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• v.24 no.12A
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• pp.2002-2007
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• 1999

In this paper, the n-channel poly-Si thin-film transistors (poly-Si TFT's) formed by solid phase crystallization (SPC) on glass were investigated by measuring the electrical properties of poly-Si films, such as I-V characteristics, mobility, leakage current, threshold voltage, and subthreshold slope. It is done to decide to be applied on TFT-LCD with large-size and high density. In n-channel poly-Si TFT with 2, 10, 25$\mu\textrm{m}$ of channel length, the field effect mobilities are 111, 126 and 125 $\textrm{cm}^2$/V-s and leakage currents are 0.6, 0.1, and 0.02 pA/$\mu\textrm{m}$, respectively. Low threshold voltage and subthreshold slope, and good ON-OFF ratio are shown, as well. Thus, the poly-Si TFT’s used by SPC are expected to be applied on TFT-LCD with large-size and high density, which can integrate display panel and peripheral circuit on a large glass substrate.

• Journal of the Korean Child Neurology Society
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• v.26 no.4
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• pp.284-287
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• 2018

Tuberous sclerosis complex (TSC) is an autosomal dominant disorder caused by mutation of one of two genes, TSC1 (encoding hamartin, 9q34) and TSC2 (encoding tuberin, 16p13). It invades the central nervous system and various parts of the body, causing various symptoms. Crohn's disease (CD) is a chronic immune-mediated disease that has not been clearly elucidated. It is thought to be caused by an excessive immune response of the body to bacteria that normally exist in the digestive tract with genetic factors. No cases have been reported in which both of the above-mentioned diseases occurred simultaneously. We report a case of CD in a patient with TSC. A 12-year-old boy was brought to our hospital because of abdominal pain. Skin lesions were observed in the TSC. Fundus examination revealed a hamartoma in the right retina. Brain magnetic resonance imaging revealed a subendothelial giant cell astrocytoma (SEGA). On the basis of these findings, he was diagnosed as having TSC. Blood test results showed increased levels of inflammatory markers. On abdominal ultrasonography, his colon walls were observed to be thickened with increased vascularity of the proximal ascending colon, ileocecal valve, and terminal ileum. Colonoscopy revealed discontinuous ulcerations and inflammations of the ileum, IC valve, and cecum, similar to those found in CD. Everolimus was administered orally for the SEGA but was discontinued frequently owing to the exacerbation of CD. The possibility of CD should be kept in mind in patients with TSC considering to undergo treatment for SEGA.

• Journal of the Korean Magnetics Society
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• v.19 no.3
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• pp.113-119
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• 2009

$^{57}Fe_xCu_{1-x}O$(x = 0.0, 0.02) powders were prepared by sol-gel method and their crystallographic and magnetic hyperfine properties have been studied using X-ray diffraction and $M{\ddot{o}}ssbauer$ spectroscopy (MS). The crystal structure of the samples is found to be monoclinic without any secondary phases and their lattice parameters increase with increasing annealing temperature ($T_A$), which is attributed to an increase in oxygen-vacancy content. MS measurements at room temperature indicate that $Fe^{3+}$ ions substitute $Cu^{2+}$ sites and ferromagnetic phase grow with increasing $T_A$. Magnetic hyperfine and quadrupole interactions of $^{57}Fe_{0.02}Cu_{0.98}O$ ($T_A=500^{\circ}C$) in the antiferromagnetic state at 17 K have been studied, yielding the following results: $H_{hf}=426.94\;kOe$, ${\Delta}E_Q=-3.67\;mm/s$, I.S.=0.32 mm/s, ${\theta}=65^{\circ}$, ${\phi}=0^{\circ}$, and ${\eta}=0.6$.

• Proceedings of KOSOMES biannual meeting
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• 2004.05b
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• pp.107-112
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• 2004

In order to improve the safety r! ship berthing and the efficiency r! berth operation in the harbour, the berthing energy acting on a ship in berthing maneuver need to be estimated properly. The berthing energy is used as one q the criteria to determine the maximum permissible load of fender as well as important factors to establish the berthing speed and the required power r! tug-beat for pilot and ship operator. In this study, some problems r! present the method of berthing energy are discussed on the basis of the hydrodynamic aspects. Then, series calculations of berthing energy are carried out considering the effect of water depth on added mass and the ship shape for container series from 1,600TEU to 12,000TEU.

• Korean Journal of Optics and Photonics
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• v.10 no.2
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• pp.162-168
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• 1999

A new design of four-pass dye laser amplifier affording a narrow-bandwidth pulsed output is demonstrated to suppress the amplified spontaneous emission(ASE) carried by the amplifier output and reduce the possibility of parasitic oscillation in the amplifier. By the direct pulsed amplification of a cw 100 mW dye laser under a Q-switched doubled Nd:YAG laser pumping with energy of 5.6 mJ/pulse, high-peak-power pulsed output with 1.5-mJ energy in 130-MHz bandwidth is obtained corresponding to a power gain greater than $2{\times}10^6$ and an energy efficiency of 27%. The ASE ratio in the four-pass amplifier output is dramatically reduced by using a diffraction grating in the amplifier. Compared with the results obtained from the normal operation of the amplifier with no frequency-selective device, the ASE ratio is reduced by a factor in excess of 10 to remain under 1.5% of the amplifier output whereas the total output energy is slightly increased by ~4%.

• KIISE Transactions on Computing Practices
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• v.21 no.1
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• pp.94-99
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• 2015

With the recent machine learning paradigm of using nonparametric Bayesian statistics and statistical inference based on random sampling, the Dirichlet distribution finds many uses in a variety of graphical models. It is a multivariate generalization of the gamma distribution and is defined on a continuous (K-1)-simplex. This paper presents a sampling method for a Dirichlet distribution for the problem of dividing an integer X into a sequence of K integers which sum to X. The target samples in our problem are all positive integer vectors when multiplied by a given X. They must be sampled from the correspondingly gridded simplex. In this paper we develop a Markov Chain Monte Carlo (MCMC) proposal distribution for the neighborhood grid points on the simplex and then present the complete algorithm based on the Metropolis-Hastings algorithm. The proposed algorithm can be used for the Markov model, HMM, and Semi-Markov model for accurate state-duration modeling. It can also be used for the Gamma-Dirichlet HMM to model q the global-local duration distributions.

• Journal of Navigation and Port Research
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• v.29 no.8 s.104
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• pp.673-678
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• 2005

In order to improve the safety of ship berthing and the efficiency of berth operation in the harbour, the berthing energy acting on a ship in berthing maneuver need to be estimated properly. The berthing energy is used as one of the criteria to determine the maximum permissible load q{ fender as well as important factors to establish the berthing speed and the required power of tug-boat for pilot and ship operator. Some problems of berthing energy are discussed on the basis of the hydrodynamic aspects. Then, series calculations of berthing energy are carried out considering the effect of water depth on added mass and the ship shape for container series from 1,600TEU to 12,000TEU.

• Journal of The Korean Association of Information Education
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• v.11 no.1
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• pp.79-89
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• 2007

Considering the continuous increase of teenagers' Internet use and the high rate of their participation in online communities, educators need to devote efforts to minimize the negative function of teenagers' Internet use and to guide them to experience positive aspects of Internet. Through activities in online communities, teenagers can experience various socialities and explore their self-consciousness. However, on the other hand many communities do not provide teenagers with considerate care. This may cause conflict in their sense of value and mislead them. Through this study, online learning community is designed and developed, which can reflect teenagers' various needs and connect their needs with learning experiences. The community consists of the following categories: 'about e-Tivity'(community vision, general information, list of activities, Q&A), 'activity space for teens'(event hall, data park, e-Tivity center), 'administrative space for teachers and managers'(research room, management room), and 'teen's private space'(my room, my avatar).