• Journal of Microbiology and Biotechnology
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• v.11 no.1
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• pp.17-20
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• 2001

Whole-cell attachment by covalent linkage, thereby simulating natural and specific attachments, improves the osmotolerance of Saccharomyces cerevisiae cells. The enhanced osmoresistance is correlated with a decrease in the intercellular concentration of trehalose and accompanied by membrane compositional changed. The results obtained indicate that yeast cell-support (physical) contact is sensed and responded to.

• Journal of Biomedical Engineering Research
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• v.7 no.2
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• pp.119-132
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• 1986

Poly (2-Hydroxyethyl methacrylate-co-r-methacryloxypropyl triethyl silane) and Poly (2-HydroHyethyl rnettacrylate-co-r-methacrylonypropylmethyl tistrimethyl siloxysilane)

• Bulletin of the Korean Chemical Society
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• v.32 no.7
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• pp.2183-2186
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• 2011

A series of pyrimidoquinoline derivatives was synthesized in good yield and short reaction times by reaction of 3-arylaminoisoxazol-5(2H)-ones with derivatives of 2-chloro-3-formylquinoline in toluene under reflux conditions.

• Bulletin of the Korean Chemical Society
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• v.34 no.11
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• pp.3477-3480
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• 2013

• Applied Chemistry for Engineering
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• v.35 no.1
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• pp.8-15
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• 2024

In this study, nitrogen plasma treatment was performed in 5, 10, and 15 minutes to improve the tetracycline adsorption performance of activated carbon. All nitrogen plasma-treated activated carbons showed improved tetracycline adsorption compared to untreated activated carbons. The nitrogen functional groups in activated carbon lead to chemisorption with tetracycline via π-π interactions and hydrogen bonding. In particular, in the nitrogen plasma treatment at 80 W and 50 kHz, the activated carbon treated for 10 minutes had the best adsorption performance. At this time, the nitrogen content on the surface of the activated carbon was 2.03% and the specific surface area increased to 1,483 m²/g. As a result, nitrogen plasma treatment of activated carbon improved its physical and chemical adsorption capabilities. In addition, since the adsorption experimental results were in good agreement with the Langmuir isotherm and pseudo-second order model, it was determined that the adsorption of tetracycline on the nitrogen plasma-treated activated carbon was dominated by chemical adsorption through a monolayer. As a result, nitrogen plasma-treated activated carbon can be used as an adsorbent to efficiently remove tetracycline from water due to the synergistic effect of physical adsorption and proactive chemical adsorption.

• Applied Chemistry for Engineering
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• v.10 no.7
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• pp.1066-1072
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• 1999

The physical properties of polymer concrete were investigated for development of high-performance construction materials. Various specimens of polymer concrete were prepared using unsaturated polyester resin as the polymer-binder with the various dosage of calcium carbonate as microfiller (5~20 wt %) and fine aggregate(10~50 wt %). For the evaluation of the physical properties of polymer concretes, tests such as compressive strength, flexural strength, water absorption test, hot water immersion test, acid resistance test and pore size distribution analysis were conducted. As a result, it is concluded that compressive and flexural strengths of polymer concretes increased up to 4 times than those of conventional cement concrete. Whereas the compressive and flexural strengths of polymer concretes tested after hot water immersion, compared with those of polymer concretes tested before hot water immersion, decreased about 67%, 47%, respectively. By hot water immersion, total pore volume and porosity(%) of polymer concretes were remarkable increased due to decomposition of polymer binder. And also, it is showed that water absorption(%) and weight loss(%) of polymer concrete specimens by acid immersion, compared with those of ordinary portland cement concrete, decreased about 1/100, 1/27, respectively.

• Korean Journal of Agricultural Science
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• v.46 no.1
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• pp.205-217
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• 2019

The aim of this study was to identify land resources because food production and supply in North Korea have been at risk due to variations in its seasonal climate. More than three-fifths of the soils are locally derived from the weathering of granitic rocks or various kinds of schists developed from crystalline rocks. Well-developed reddish brown soils derived from limestone are found in the North Hwanghae province and in the southern part of the South Pyeongan province. Additionally, a narrow strip of similarly fertile land runs through the eastern seaboard of the Hamgyong and Kangwon Provinces. The loss of clay particles and organic matter are major causes of degradation in the soil physical and chemical properties in North Korea. 75% of the areas converted from forests became croplands, and 69% of the land converted to croplands came from forests. The net forest loss was quite small from the 1990s to the 2000s. However, deforestation in areas with a slightly lower elevation and gentler slope between 1997 and 2014 led to severe soil erosion resulting in a drastic change in the physical and chemical properties of the soil which influenced cropland stability and productivity. Therefore, the drastic changes in land cover as well as in the physical and chemical properties of the soil caused by various geographical features have seriously influenced the productivity of crops in North Korea.

• Elastomers and Composites
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• v.50 no.3
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• pp.196-204
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• 2015

Crosslink density of a rubber vulcanizate determines the chemical and physical properties, while bound rubber is an important factor to estimate reinforcement of a filled rubber compound. Extender oil is added to a raw rubber with very high molecular weight for improving processability of a rubber composite. Influence of extender oil on crosslink density, bound rubber formation, and physical properties of solution styrene-butadiene rubber (SSBR) composites with differing microstructures was investigated. Crosslink densities of non-oil-extended SSBR (NO-SSBR) vulcanizates were higher than those of oil-extended SSBR (OE-SSBR) ones. Bound rubber contents of NO-SSBR compounds were also greater than those of OE-SSBR ones. The experimental results could be explained by interfering of extender oil. The OE-SSBR vulcanizates had low modulus but long elongation at break, whereas the NO-SSBR ones had high modulus but short elongation at break. It was found that the crosslink densities affected the physical properties more than the bound rubber contents. The moduli increased with increase in the crosslink density irrespective of extender oil, while the elongation at break decreased. Each variation of the tensile strengths of NO-SSBR and OE-SSBR vulcanizates with the crosslink density showed a decreasing trend. Tear strength of the OE-SSBR vulcanizate increased with increase in the crosslink density, whereas variation of the tear strength of NO-SSBR vulcanizate with the crosslink density showed a weak decreasing trend.

• Bulletin of the Korean Chemical Society
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• v.30 no.9
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• pp.1946-1950
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• 2009

Tripod-shaped liquid crystals with $sp^3$ nigrogen at the apex were prepared from triethanolamine. Their physical properties were investigated by using optical microscopy, differential scanning calorimetry, and X-ray diffraction measurements. The XRD study suggests that the tripod-shaped molecules show the 2D-ordered phase of either the frustrated smectic layer structure or discotic columnar phases.

• Proceedings of the Korean Society of Potoscience Conference
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• spring
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• pp.40-40
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• 1999