• KSBB Journal
• /
• v.11 no.2
• /
• pp.193-200
• /
• 1996

In molecular biology, type-II restriction endonuclease, which specifically recognize and cleave DNA at a limited number of sites, have been exploited as a means of characterizing DNA fragments, DNA mapping for genetic engineering. Type-II restriction endonucleases have been found to modulate their substrate specificity under modified conditions such as extreme pH, ionic strength, high enzyme concentration, substitution of metallic cofactors or addition of organic solvents. This study was initiated to investigate the modification of recognition specificity of BamHI according to the different pH and organic solvent under the given buffer condition. The specificity of BamHI is highly depends on the presence of hydrophobicity (LogP: partition coefficient) and pH of reaction solution. The specificity of BamHI is changed in range of LogP -1.03∼-1.35(at pH 7.5), -1.03∼-2.5 (at pH 8.0), -0.75∼-0.25(at pH 8.5), 0.32∼-2.5(at pH 8.9), respectively. Alteration of specificity appears in lower concentration of organic solvent when the reaction occurs in more alkali pH. For example, in DMSO solution, alteration of specificity appears in 20% concentration at pH 7.5 but in 4% concentration at pH 8.9.

• Journal of the Korean Society for Library and Information Science
• /
• v.39 no.3
• /
• pp.139-163
• /
• 2005

Various corpus-based approaches, rhetorical roles of discourse structure, and unifications of similar sentences were applied to construct the automatic Ext/Sums(extracts and summaries). Rhetorical roles of sentences like objective, method, background, result, conclusion, etc. for making elastic Ext/Sums were established and extraction engines according to respective role were prepared. The $90\%$ of Success rate in extracting the important sentences of sample articles was accomplished. Rearranging the selected sentences, it used unification of similar sentences using the cosine coefficient equation, deletion of unnecessary modification and insertion clauses, junction of short sentences, and connection of sentences able to link. They suggest the methods applying rhetorical roles of sentences, meaning and signature of noun and verb in clauses, and cue words and location will be researched to construct the more effective Ext/Sums.

• Tribology and Lubricants
• /
• v.36 no.4
• /
• pp.244-252
• /
• 2020

Materials manufactured by powder metallurgy (PM) are widely used in various applications such as water pump, shock absorber, and airplane components due to the reduction in the cost and weight. In this study, tribological properties of carbon steel subjected by surface treatment were investigated. The main purpose is to increase the strength and improve the tribological properties by reducing pores that formed by PM. Moreover, the surface treatment was carried out at room and high temperatures (RT and HT). The surface roughness of the untreated (NON) and treated (AFTER) samples was measured. It was found that the surface roughness was reduced after both the RT AFTER and HT AFTER compared to RT NON sample. The tribological properties of the samples were performed against bearing steel ball under dry conditions. The friction coefficient of the RT NON samples was reduced by 22% and 56% RT AFTER and HT AFTER, respectively. The wear volume of the RT NON sample was also reduced by 43% and 87% RT AFTER and HT AFTER, respectively. Tribocorrosion tests were also performed and it was found that the surface of the RT AFTER, HT AFTER samples was less corroded compared to RT NON sample. The HT AFTER sample demonstrated a relatively higher corrosion potential in comparison with the RT AFTER samples. Hence, it was confirmed that after surface modification the surface roughness and hardness of the samples were significantly improved resulting in improvement in tribological and tribocorrosion behaviors of PM carbon steel.

• Journal of Korean Society of Coastal and Ocean Engineers
• /
• v.17 no.1
• /
• pp.41-46
• /
• 2005

The seismic response characteristics of a port structure were investigated by the earthquake analyses of the structure subjected to high-, low-frequency component, and Uljin earthquakes. In the Fluid-Structure-Soil Interaction(FSSI) analysis, the fluid is modeled by the 4-node quadrilateral element which is a modification of a structural plane element, and the port structure and foundation is modelled by the plane strain element. Since the present method directly models the fluid-structure-soil interaction system using finite element method, it can be easily applied to the dynamic analysis of a 2-D fluid-port-soil system with complex geometry. The results of the seismic coefficient. added mass, and FSSI methods are compared. The results showed that the earthquake with high frequency components more affects the seismic response of the structure than that of low frequency components.

• Journal of the Korean Society for Marine Environment & Energy
• /
• v.15 no.3
• /
• pp.163-169
• /
• 2012

In this paper, model test on the Tapdong's revetment at Jeju-si has been conducted to figure out the causes of frequent occurrence of wave overtopping and to suggest the action plan. In the model test, the reflection coefficients were measured according to the change of wave periods for with and without armor stones. Also, the wave overtopping rate and the wave pressures inside revetment structure for 4 types of upper block were estimated for various wave heights and wave periods, which are chosen based on the NE design wave with 50 year return period. It is found that the increase of the upper structure's height and the modification of the curved protruding shape are effective in reducing the overtopping rate.

• The Transactions of the Korea Information Processing Society
• /
• v.6 no.4
• /
• pp.1112-1119
• /
• 1999

Digital watermarking is to embed imperceptible mark into image, video, audio and text data to prevent the illegal copy of multimedia data, arbitrary modification, and also illegal sales of the copes without agreement of copyright ownership. The DCT(discrete Cosine Transforms) transforms of original image is conducted in this research and these DCT coefficients are expanded by Fourier series expansion algorithm. In order to embed the imperceptible and robust watermark, the Fourier coefficients(lower frequency coefficients) can be calculated using sine and cosine function which have a complete orthogonal basis function, and the watermark is embedded into these coefficients, In the experiment, we can show robustness with respect to image distortion such as JPEG compression, bluring and adding uniform noise. The correlation coefficient are in the range from 0.5467 to 0.9507.

• Tribology and Lubricants
• /
• v.30 no.1
• /
• pp.59-63
• /
• 2014

Laser Surface Texturing(LST) is a surface engineering process used to improve tribological characteristics of materials by creating patterned microstructures on the mechanical contact surface. In LST technology, a pulsated laser beam is used to create arranged dimples on a surface by a material ablation process, which can improve such as load capacity, wear resistances, lubrication lifetime, and reduce friction coefficients. In the present study, the effect of multi-scale LST on lubricant regime was investigated. A pulsed Nd:YAG laser was applied on the bearing steel(AISI 52100) to create arranged dimples. To optimize the surface texturing effect on friction, multi-scale texture dimples with some specific formula arrays were fabricated by combining circles, ellipses and the laser ablation process. The tribological testing of multi-scale textured surface was performed by a flat-on-flat unidirectional tribometer under lubrication and the results compared with that of the non-textured surface. Through an increase in sliding speed, the beneficial effect of multi-scale LST performance was achieved. The multi-scale textured surface had lower friction coefficient performances than the non-textured surface due to the hydrodynamic lubrication effect.

• Journal of Environmental Health Sciences
• /
• v.13 no.1
• /
• pp.47-57
• /
• 1987

Owing to the modification of testing methods of disinfectants or antiseptics, variations of bacteria according to characteristics of regions and resistance changes of bacteria, it is necessary that the bactericidal activities of disinfectants or antiscptics should be reevaluated nowadays. This study was carried out to reevaluate in the vitro bactericidal activity of Chlorhexidine gluconate solution. The results of experiment were summarized as follows. 1. For Chlorhexidine gluconate solution, minimal inhibitory concentrations of total bacteria taken from sewage water and Legionella bozemanii were $2.0\times 10^{-3}$%, $1.0\times 10^{-2}$%, respectively and were comparatively high. Minimal inhibitory concentration of Shigella flexneri was $1.6\times 10^{-4}$%, and was comparatively low. 2. For total bacteria taken from sewage water, it was killed within 15 minute in 0.1% Chlorhexidine gluconate solution when number of cells was $1.6\times 10^7$/ml. 3. For 0.0125% Chlorhexidine gluconate solution, decimal reduction times of Ps. aeruginosa, S. typhi, E. Coli were 45 sec, 25 sec, 18 sec repectively. For 1%, 0.125% Chlorhexidine gluconate solution, decimal reduction times of Legionella bozemanii were 10 sec, 45 sec respectively. 4. There was significant difference in the bactericidal activity of Chlorhexidine gluconate solution according to temperattire. Phenol coefficient of Chlorhexidine gluconate solution as using Staph. aureus was 100 and comparatively higher than that of other disinfectants. In comparison with other disinfectants, Legionella bozemanii was killed within 5 minutes in 0.02% KMnO$_4$ and 0.125% Chlorhexidine giuconate solution but was not killed within 3 minutes in 1% 0-cresol, 1% Phenol.

• The Journal of the Institute of Internet, Broadcasting and Communication
• /
• v.12 no.4
• /
• pp.15-22
• /
• 2012

This paper deals with the performance comparison and evaluation of blind adaptive equalizer, the PMCMA-MDD and DW-MCMA, that is used for compensation of the amplitude and phase distortion which occurs in the time dispersive channel. Basically, these algorithms are modification of MCMA cost function in order to obtain the fast convergence speed and reduced residual isi by taking the parallel and serial double structured and the combination of the concept of RCA for the updating the tap coefficient. We implements the algorithm of it and compare the recovered constellation, residual isi, MSE characteristics curve and SER in the signal to noise ratio given the time dispersive channel. As a result of simulation, the PMCMA-MDD has a good in recovered constellation than DW-MCMA. But in the SER, the DW-MCMA has a good than PMCMA-MDD.

• Aerospace Engineering and Technology
• /
• v.8 no.2
• /
• pp.140-148
• /
• 2009

MOV(Main Oxidizer shut-off Valves) control the combustion of launch vehicle systems by the supply and the isolation of liquid oxygen to a main combustion chamber in launch vehicle systems. Moreover, in the steady operational state, the MOV should secure a constant flow rate of liquid oxygen for combustion instability in the combustion chamber. Concerning the development of MOV, TM(Technology Model) has been manufactured and normal operations of the valve have been verified. However, the Cv of TM has been proved to be too low as compared with a design specification value. Therefore, CFD analysis have been performed by modification of the configurations of TM in order to increase sufficiently Cv of EM(Engineering Model), which is the following model of TM. The modifications of TM configurations such as partial scale-up of valve, increase of stroke length, and outlet angle of 120o would result in a considerable augmentation of Cv. It has been verified by flow capacity tests that the improved Cv of EM is min. 212, which is higher than Cv of TM, 161 by about 32%.