• Journal of the Korean Ceramic Society
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• v.31 no.2
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• pp.137-146
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• 1994

This experiments were focused on a modification of mechamical properties and structure in porous aluminum titanate ceramics by new additives which have been not researched yet. These were consisted of four kinds of additives i.e. Bi2O3, FeO, ZnO and NiO by addition amount of 1 wt% and 5 wt% respectively. The addition of Bi2O3 retarded a degree of syntehsis of aluminum titanate and accelerated in FeO, ZnO, NiO additives. Also, the most effective accelerator in synthesis of alunium titanate was FeO. A additives for the most effective of modification of microstructure, sharp distribtion of pore size and mechanical proterties was on ZnO addition and showed the lowest average pore size and narrowed pore size distribution. In order to improve of microstructure and pore size distribution in porous aluminum titanate ceramics was desired the addition amount of 1 wt% compare to 5 wt%.

• BMB Reports
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• v.51 no.5
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• pp.211-218
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• 2018

Chromatin is an intelligent building block that can express either external or internal needs through structural changes. To date, three methods to change chromatin structure and regulate gene expression have been well-documented: histone modification, histone exchange, and ATP-dependent chromatin remodeling. Recently, a growing body of literature has suggested that histone tail cleavage is related to various cellular processes including stem cell differentiation, osteoclast differentiation, granulocyte differentiation, mammary gland differentiation, viral infection, aging, and yeast sporulation. Although the underlying mechanisms suggesting how histone cleavage affects gene expression in view of chromatin structure are only beginning to be understood, it is clear that this process is a novel transcriptional epigenetic mechanism involving chromatin dynamics. In this review, we describe the functional properties of the known histone tail cleavage with its proteolytic enzymes, discuss how histone cleavage impacts gene expression, and present future directions for this area of study.

• BMB Reports
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• v.31 no.2
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• pp.139-143
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• 1998

The catabolic ${\alpha}-acetolactate$ synthase purified from Serratia marcescens ATCC 25419 was rapidly inactivated by the tryptophane-specific reagent, N -bromosuccinimide, and the arginine-specific reagent, phenylglyoxal. The enzyme was inactivated slowly by the cysteine-specific reagent N-ethylmaleimide. The second-order rate constants for the inactivation by N-bromosuccinimide, phenylglyoxal. and N -ethylmaleimide were $114,749M^{-1}min^{-1}$, $304.3M^{-1}min^{-1}$, and $5.1M^{-1}min^{-1}$, respectively. The reaction order with respect to N-bromosuccinimide, phenylglyoxal, and N-ethylmaleimide were 1.5,0.71, and 0.86, respectively. The inactivation of the catabolic aacetolactate synthase by these modifying reagents was protected by pyruvate. These results suggest that essential tryptophane, arginine, and cysteine residues are located at or near the active site of the catabolic ${\alpha}-acetolactate$ synthase.

• Journal of the Korean Society for Precision Engineering
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• v.31 no.5
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• pp.441-449
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• 2014

Thermoplastic fusion bonding is widely used to seal polymer microfluidic devices and optimal bonding protocol is required to obtain a successful bonding, strong bonding force without channel deformation. Besides, UV modification of the PMMA (poly-methyl methacrylate) is commonly used for chemical or biological application before the bonding process. However, study of thermal bonding for the UV modified PMMA was not reported yet. Unlike pristine PMMA, the optimal bonding parameters of the UV modified PMMA were $103^{\circ}C$, 71 kPa, and 35 minutes. A very low aspect ratio micro channel (AR=1:100, $20{\mu}m$ depth and $2000{\mu}m$ width) was successfully bonded (over 95%, n>100). Moreover, thermal bonding of multi stack PMMA chips was successfully demonstrated in this study. The results may applicable to fabricate a complex 3 dimensional microchannel networks.

• Journal of the Korea Safety Management & Science
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• v.9 no.5
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• pp.147-156
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• 2007

With the radical change of business environment, all service companies' employees are forced to provide many customers with high service quality every day, and the extra role(or organizational citizenship behavior) is more imperative than other industry. The purpose of this paper is to introduce Luthans & Kreitner's Organizational Behavior Modification(OB Mod) model to improve organizational citizenship behavior and service quality. With analyzing the relationships among target behavior(service quality), antecedents(OCB), and consequences(customer satisfaction), this paper reviewed OB Mod's 5 stages; identifying, measuring, functional analysis of the behavior, development of an intervention strategy, evaluation. This model has found to be useful in finding and improving troublesome employee behaviors in USA, but not been verified in Korea. Thus it is recommended to review the difference of organizational culture and practices before introducing the model.

• 한국정보통신설비학회:학술대회논문집
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• 2008.08a
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• pp.551-555
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• 2008

In these days, compressed file is useful in internet environment and has many advantages. So a lot of data hiding algorithms works on JPEG compressed file. Of course they know basic rules of transformation and quantization and they utilize those rules to implement their programming. But most of them evaluate the affection of data hiding after data modification. We propose how to predict the affection of data modification in course of data hiding process. Through some kind of experiments, several valuable facts are revealed which used in data hiding in compressed domain such as JPEG. These facts will improve existing data hiding algorithms (F3, F4 and F5 which including Matrix Encoding)[1],[5],[6].

• Journal of Nutrition and Health
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• v.15 no.3
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• pp.202-211
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• 1982

A modification of a microbiological assay of vitamin $B_{12}$ was made and used to determine the vita­min levels during kimchi fermentation. A cyanide-buffer solution of pH 6.0 replaced the metabisufite-buffer specified in the A.O.A.C. method. The vitamin $B_{12}$ activity was decreased by blending kimchi samples for 5 minutes and retained the activity by steaming for 10 minutes before blending. The alkali hydrolysis of kimchi at pH 12.0 for 30 minutes at $121^{\circ}C$ was sufficient to destroy the vitamin $B_{12}$ and permit the detection of analogs with the same assay organism. Vitamin $B_{12}$ reached a maximum of 47ng/100g during the fermentation of kimchi ${15}\;4^{\circ}C.$ Inoculation of the kimchi with Propionibacterium shermanii (ATCC 13673) increased the vitamin production to a maximum of 102ng/100g at 1 week of fermentation. Soy flour (0.5%) or beef extract (0.05%), which were regarded as protein sources, added to the inoculated kimchi further increased the vitamin $B_{12}$ activity to 197 and 203ng/100g.

• Geomechanics and Engineering
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• v.13 no.5
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• pp.757-774
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• 2017

The subgrade reaction modulus of a large mat foundation was investigated by using a numerical analysis and a field case study. The emphasis was on quantifying the appropriate method for determining the subgrade reaction modulus for the design of a flexible mat foundation. A series of 3D non-linear FE analyses are conducted with special attention given to the subgrade reaction modulus under various conditions, such as the mat width, mat shape, mat thickness, and soil condition. It is shown that the distribution of the subgrade reaction modulus is non-uniform and that the modulus of subgrade reaction at both the corners and edges should be stiffer than that at the center. Based on the results obtained, a simple modification factor for the subgrade reaction modulus is proposed depending on the relative positions within the foundation in weathered soil and rocks.

• Journal of the Society of Naval Architects of Korea
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• v.42 no.5 s.143
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• pp.506-515
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• 2005

Novel ships are commonly required iterative hull form modifications until she get reputation for new marine environment. Small FRP boats are manufactured in a identical shape with a mould. It implies that every modification step requires great time and expense which makes it difficult to improve the hull form promptly. Domestic hull form of small fishing boat of force has been evolved from the traditional hull form of developable shape. Utilizing this typical developable characteristics of small boats, ,New mouldless production method for FRP boat has been suggested and it is confirmed that the method is recommendable for a petty order of hull in evolving period of hull form development.

• Membrane and Water Treatment
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• v.10 no.5
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• pp.381-385
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• 2019

Surface modification is very efficient and scalable approach to achieve improved membrane performance. We treated Reverse Osmosis Thin Film Composite (TFC RO) membrane with various concentrations of Polyethylene Glycol (PEG), a hydrophilic polymer after activation with sodium hypochlorite. This treatment resulted in an increment of the water flux by 43% and the salt rejection by 2.36% for the 3000 mg/l PEG-treated membrane. Further, these PEG-treated membranes were exposed to a mixture of 3000 mg/l PEG and 1000 mg/l sodium hypochlorite for 1 hour. Further modification of this membrane by PEG and sodium hypochlorite mixture increased the water permeance up to 133% when compared with the virgin TFC RO membrane. We characterized the treated membranes to understand the changes in wettability by contact angle analysis, changes in surface morphology and roughness by scanning electron microscope (SEM) and atomic force microscope (AFM) analysis.