• Journal of the Korea Academia-Industrial cooperation Society
• /
• v.10 no.6
• /
• pp.1164-1169
• /
• 2009

In this study, the bracket for car was designed in 3D using Cimatron Die Design, one of the automatic modules. To facilitate the stamping of the product, the layout of the strip was adjusted slightly. The blank layout of the double-width, 2-line, 2-pull out inner carrier was then optimized as a single arrangement. 3D design was completed in 11 processes.

• Journal of Information Display
• /
• v.2 no.4
• /
• pp.57-62
• /
• 2001

Green-emitting $Zn_2SiO_4$:Mn phosphor particles having a spherical shape and high luminescence intensities under VUV were prepared by spray pyrolysis process under severe preparation conditions. The type of precursor solutions affected the morphology and luminescence characteristics of the prepared particles. The particles prepared from the clear solution by laboratory-scale process had spherical shape and dense morphology, while the particles prepared from the severe preparation conditions had rough surface and collapsed structure. However, the particles prepared from the colloidal solution utilizing fumed silica were spherical in shape and filled morphology at the severe preparation conditions of high flow rate of carrier gas, high concentration of solution, and large reactor size. The prepared $Zn_2SiO_4$:Mn phosphor particles with complete spherical shape had higher photoluminescence intensity than that of the commercial product prepared by solid state reaction.

• Journal of the Korean Chemical Society
• /
• v.55 no.6
• /
• pp.978-982
• /
• 2011

In order to enhance the target action of chitosan-based drug, this paper firstly prepared phenylalanyl-glycylchitosan (Phe-Gly-CS) by grafting the key intermediate, bromoacetyl-phenylalanine (BA-Phe) onto chitosan. Then the target sugar molecule, lactobionic acid (LA), was grafted to Phe-Gly-CS and the topic compound lactobionic acid grafted phenylalanyl-glycyl-chitosan (Phe-Gly-CS-LA) was finally obtained in a yield of 78.8%. The product were characterized by FTIR, MS and 1H NMR. The preparing condition of BA-Phe was optimized as follows: the best pH was 10-11, the optimum temperature was $-4^{\circ}C$, the reaction time was 1.5 h.

• KIEE International Transactions on Electrophysics and Applications
• /
• v.5C no.6
• /
• pp.246-250
• /
• 2005

The forward voltage drop of IGBT is studied numerically and analytically as a function of gate length. An analytical expression is presented for the first time for the surface potential variation along the channel layer under the gate of IGBT. The surface potential drop and the carrier density near the surface allow calculation of the forward voltage drop of IGBT analytically as a function of the gate length. The voltage-drop in the drift region near the gate decreases exponentially, whereas that on the surface increases linearly with increasing the gate length, the sum of which exhibits an optimum gate length, resulting in a minimum forward voltage drop. Based on the surface potential drop, a remodelling of the forward voltage drop of IGBT is also proposed.

• Proceedings of the KIEE Conference
• /
• 1996.07b
• /
• pp.1301-1303
• /
• 1996

A new automatic frequency control(AFC) tracking algorithm, which we call a rotational decision directed AFC(RDDAFC) is proposed for QPSK demodulation at the digital direct broadcasting satellite(DBS). In order to prevent the presence of the residual phase difference between symbols received at k and k-l by the CPAFC[1] as well as the AFC based on $tan^{-1}$ circuit[2], the RDDAFC rotates the decision boundary for the kth received symbol by the frequency detector output of the (k-1)th received symbol before passing through the cross product discriminator. Test results show that the total pull-in time of the RDDAFC and PLL was 0.13msec under a carrier frequency offset of 2.4MHz when S/N equals 2dB.

• Proceedings of the KAIS Fall Conference
• /
• 2011.12a
• /
• pp.330-333
• /
• 2011

Allomatrix (Wright Medical Tech, Inc., USA), is a newly designed, injectable putty with a reliable demineralized bone matrix(DBM), derived from human bone. The compound contains 86% DBM and other bone growth factors such as bone morphogenic protein (BMP)-2, BMP-4, insulin-like growth factor (IGF)-1, and transforming growth factor (TGF)-${\beta}1$. It has excellent os-teoinduction abilities. In addition, DBM is known to have osteoconduction capacity as a scaffold due to its collagen matrix. This product contains a powder, which is a mix of DBM and surgical grade calcium sulfate as a carrier. A practitioner can blend the powder with calcium sulfate solution, making a putty-type material which has the advantages of ease of handling, better fixation, and no need for a membrane, because it can function as membrane itself. This study reports the clinical and radiographic results of various guided bone regeneration cases using Allomatrix, demonstrating its strong potential as a graft material.

• Proceedings of the Korean Institute of Navigation and Port Research Conference
• /
• 2010.10a
• /
• pp.180-181
• /
• 2010

An estimation algorithm of collision risk among multiple ships has been developed in order to reduce human error and prevent collision accidents. The algorithm is designed to calculate the collision risk among ships based on Fuzzy theory by using AIS data as traffic information. In this paper, to validate the algorithm, the AIS data of actual collision accident, which occurred between a product carrier and a cargo carrier in Busan harbor in 2009 are collected. The replay simulation is carried out on the actual AIS data and the collision risk is calculated in real time. In this paper, the features of the estimation algorithm of collision risk and the results of replay simulation based on AIS data of actual collision accident are discussed.

• Journal of Periodontal and Implant Science
• /
• v.39 no.sup2
• /
• pp.269-278
• /
• 2009

Purpose: The aim of this study was to investigate matrix metalloproteinase 1 (MMP-1) gene polymorphism (1G/2G at -1607 and A/G at -519) in Korean subject and to assess the association between polymorphism and periodontal status. Methods: Forty nine generalized aggressive periodontitis (GAP) patients and 57 periodontally healthy children were recruited and genomic DNA was extracted from buccal swab. The polymorphisms of MMP-1 promoter genes were determined by polymerase chain reaction and restriction fragment length product (PCR-RFLP) method. The distribution of genotype and allele frequency was compared between 2 groups by ${\chi}^2$ test. Results: There was a significant difference in the distribution of genotypes and frequency of alleles between the GAP and reference groups at the position - 519 of MMP-1 gene promoter (P<0.05). Allele G carrier rate was significantly lower in GAP group than that of the reference group (P< 0.001). At the position -1607 of MMP-1 gene promoter, genotype distribution and allele frequency showed no statistically significant difference between the groups. However, in the female group, a significant difference was observed between the groups for the genotype distribution, allele frequency and allele 1G carrier rate (P< 0.05). Conclusions: The DNA polymorphism at the MMP-1 gene promoter might be associated with GAP in Korean.

• Journal of Navigation and Port Research
• /
• v.34 no.10
• /
• pp.727-733
• /
• 2010

An estimation algorithm of collision risk among multiple ships has been developed in order to reduce human error and prevent collision accidents. The algorithm is designed to calculate the collision risk among ships based on Fuzzy theory by using AIS data as traffic information. In this paper, to validate the algorithm, the AIS data of actual collision accident, which occurred between a product carrier and a cargo carrier in Busan harbor in 2009 are collected. The replay simulation is carried out on the actual AIS data and the collision risk is calculated in real time. In this paper, the features of the estimation algorithm of collision risk and the results of replay simulation based on AIS data of actual collision accident are discussed.

• Journal of Pharmaceutical Investigation
• /
• v.41 no.3
• /
• pp.125-142
• /
• 2011

Solid dispersion, defined as the dispersion of one or more active ingredient in a carrier or matrix at solid state, is an efficient strategy for improving dissolution of poorly water-soluble drugs for enhancement of their bioavailability. Compared to other conventional formulations such as tablets or capsules, solid dispersion which can be prepared by various methods has many advantages. However, despite numerous studies which have been carried out, limitations for commercializing these products remain to be solved. For example, during the manufacturing process or storage, amorphous form of solid dispersion can be converted into crystalline form. That is, the dissolution rate of solid dispersion would continuously decrease during storage, resulting in a product of no value. To resolve these problems, studies have been conducted on the effects of excipients. In fact, modification of the solid dispersions to overcome these disadvantages has progressed from the first generation to the recent third generation products. In this review, an overview on solid dispersions in general will be given with emphasis on the various manufacturing processes which include the use of polymers and on the stabilization strategies which include methods to prevent crystallization.