• Proceedings of the Korea Concrete Institute Conference
• /
• 1998.04a
• /
• pp.231-236
• /
• 1998

In general, the drying shrinkage of polymer-modified mortars using redispersible polymer powders is much higher than that of unmodified mortar. The purpose of this study is to reduce the drying shringkage of polymer-modified mortars using a redispersible poly(ethylene-vinyl acetate) (EVA) powder, which is widely used for the manufacture of prepackaged-type polymer-modified mortar products at present. Polymer-modified mortars using the redispersible EVA powder with powdered shrinkage-reducing agent were prepared with various polymer-cement ratios and shrinkage-reducing agent contents, and tested for drying shrinkage and strength. From the test results, the drying shrinkage of the redispersible EVA powder-modified mortars with a powdered shrinkage agent is remarkably reduced with increasing shrinkage-reducing agent content, and becomes approximately a half of that of the redispersible EVA powder-modified mortars with the same polymer-cement ratios and without the shrinkage-reducing agent at a shrinkage-reducing agent content of 6%.

• 한국생물공학회:학술대회논문집
• /
• 2002.04a
• /
• pp.239-242
• /
• 2002

We have synthesized branched oligosaccharides (BOS) by the mixed-culture fermentation (MBOS), fructosyltransferase (FBOS) or glucosyltransferase (GBOS) with high concentration of sucrose (3M). MBOS was further modified as iron and sulfate-oligosaccharides. The modified MBOS were stable at high temperatures (up to $140^{\circ}C$) and low pHs (2 to 4). Most highly branched and modified oligosaccharide (0.34%, w/v) effectively inhibited fructose release from sucrose by Streptococcus mutans 6715 mutansucrase. FBOS, GBOS, iron-MBOS inhibited the mutansucrase activities from Streptococcus sobrinus about 46.8%, 49.2% and 43.1%, respectively. Most highly branched and modified oligo- saccharides (0.5%, w/v) effectively inhibited the fonnation of insoluble glucan and adherence of S. mutans or S. sobrinus cell in the presence of sucrose. Modified oligosaccharides affected the growth and acid production of oral pathogens. Cytotoxicity test showed that highly branched and modified oligosaccharides was non-toxic.

• Korean Journal of Air-Conditioning and Refrigeration Engineering
• /
• v.16 no.8
• /
• pp.683-690
• /
• 2004

A modified rectangular fin is analyzed by two-dimensional analytic method and finite difference method. Relative error of heat loss from the modified rectangular fin between analytic method and finite difference method is presented. Comparisons of fin effectiveness and heat loss between a modified rectangular fin and a plane rectangular fin are made as a function of the non-dimensional fin length and wing height for different positions of wings by using analytic method. The ratio of the incremental rate of heat loss to that of the area of a modified rectangular fin is shown as a function of the wing height. One of the results shows that performance of a modified fin is more improved as the wing approaches the fin root.

• Journal of the Society of Disaster Information
• /
• v.6 no.1
• /
• pp.28-43
• /
• 2010

This paper presents the field applications of polymer-modified warm asphalt mixture which can reduce the temperature during the production and field constructions. The amount of fuel consumptions and $CO_2$ diffusions can be reduced by much using the polymer-modified warm asphalt mixture instead of the conventional polymer-modified asphalt mixture. According to the research results, the polymer-modified warm asphalt mixture can be utilized without additional temperature increasement and performance sacrifice during the plant production and public service, respectively. As a result, it is considered that the application of the polymer-modified warm asphalt mixture has the potential of convenience in constructions management and reducing the environmental damages.

• Proceedings of the Korean Vacuum Society Conference
• /
• 2010.02a
• /
• pp.472-472
• /
• 2010

The tomography has played a key role in tokamak plasma diagnostics for image reconstruction. The Phillips-Tikhonov (P-T) regularization method was attempted in this work to reconstruct cross-sectional phantom images of the plasma by minimizing the gradient between adjacent pixel data. Recent studies about the comparison of the several tomographic reconstruction methods showed that the P-T method produced more accurate results. We have studied existing Laplacian matrix used in Phillips-Tikhonov regularization method and developed modified Laplacian matrix (Modified L). The comparison of the reconstruction result by the modified L and existing L showed that modified L produced more accurate result. The difference was significantly pronounced when a portion of plasma was reconstructed. These results can be utilized in the Edge Plasma diagnostics; especially in divertor diagnostics on tokamak a large impact is expected. In addition, accurate reconstruction results from received data in only one direction were confirmed through phantom test by using P-T method with modified L. These results can be applied to the tangentially viewing pin-hole camera diagnostics on tokamak.

• Food Science and Biotechnology
• /
• v.15 no.3
• /
• pp.385-391
• /
• 2006

In Korea, different kinds of genetically modified (GM) crops are under development, including GM-rice expressing insecticidal crystal (Cry) proteins of Bacillus thuringiensis (Bt) modified to change a single amino acid. In this study, amino acid (aa) sequences of modified Cry proteins were compared to that of known allergens, and Cry proteins expressed in GM-rice were identified by using Cry protein specific polyclonal antibody. The antigen-antibody reactions were compared between GM and commercial rice to assess the allergic risk of Cry proteins. This analysis showed no known allergen to have more than 35% aa sequence homology with modified Cry proteins in Bt rice over an 80 aa window or to have more than 8 consecutive identical aa. Sera from allergic patients showed some IgE reactivity via immunoblotting and enzyme-linked immunosorbent assay (ELISA), although no differences were seen between GM and commercial rice. Based on these results we conclude that GM rice with modified Cry proteins has no differences in its protein composition or allergenicity relative to commercial rice.

• Bulletin of the Korean Chemical Society
• /
• v.20 no.12
• /
• pp.1394-1398
• /
• 1999

The structures of modified Ti$(OPr^i)_4$ with chelating ligands (L) such as ethylacetoacetate (Etac), acetylacetone (Acac) and methylacetoacetate (Mtac) were identified by using IR, ¹H NMR and $^13C$ NMR spectroscopies, and the octahedral structure was confirmed after modification. The pre-edge peaks of XANES spectra of modified metal alkoxides also denoted the mixture of five-fold and six-fold structures. The EXAFS fitting results showed the local structure around Ti atom after alkoxide modification. The hydrolysis-condensation rates of modified Ti alkoxide with organic additives were investigated by ¹H NMR spectroscopy. The Ti$(OPr^i)_4$ modified by Acac was less reactive toward hydrolysis-condensation reaction than those modified by the other alkoxides, which can be attributed to the stable ligand structure between Ti$(OPr^i)_4$ and Acac. The small particle size of modified Ti$(OPr^i)_4$ sol was obtained when Acac was employed.

• Honam Mathematical Journal
• /
• v.43 no.3
• /
• pp.453-463
• /
• 2021

In this study, tubular surfaces that play an important role in technological designs in various branches are examined for the case of the base curve is not satisfying the fundamental theorem of the differential geometry. In order to give an alternative perspective to the researches on tubular surfaces, the modified orthogonal frame is used in this study. Firstly, the relationships between the Serret-Frenet frame and the modified orthogonal frame are summarized. Then the definitions of the tubular surfaces, some theorems, and results are given. Moreover, the fundamental forms, the mean curvature, and the Gaussian curvature of the tubular surface are calculated according to the modified orthogonal frame. Finally, the properties of parameter curves of the tubular surface with modified orthogonal frame are expressed and the tubular surface is drawn according to the Frenet frame and the modified orthogonal frame.

• Journal of the Korean Statistical Society
• /
• v.34 no.2
• /
• pp.153-160
• /
• 2005

In this paper, modified second order slope rotatable designs are introduced and modified slope rotatable central composite designs (SRCCD) are constructed for $2 {\le} v {\le} 17$ (v: the number of factors). Further, it can be shown for certain values of 'v', the modified SRCCD can be viewed as SRCCD constructed as with the technique of augmentation of second order rotatable design (SORD) using central composite design to SRCCD. These designs are useful in parts to estimate responses and slopes with spherical variance functions.

• Proceedings of the KIEE Conference
• /
• 2006.10c
• /
• pp.312-314
• /
• 2006

This paper describes performance of the modified gain scheduling controller by speed control of a DC motor. The modified gain scheduling controller can perform tracking at more than one equilibrium points. The modified gain scheduling controller which considers transient response according to added zero shows better result of tracking performance than the unmodified gain scheduling controller shows.