• Proceedings of the Korea Concrete Institute Conference
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• 2008.11a
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• pp.369-372
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• 2008

In this research experimentally analyzes the flow characteristics of a combined High flowing Self-Compacting Concrete of which the viscosity agent and defoaming agent addition amount are changed, to make the combined High flowing Self-Compacting Concrete that can secure the required flow performance and air amount. As a result of the experiment, the slump flow of the combined High flowing Self-Compacting Concrete added with viscosity agent increases when the viscosity agent addition amount is 0.2%(${\times}$W %). When viscosity agent addition amount increases, viscosity agent shows that it largely deviates from the regulation value in the flow time of V-funnel, which is presented in the JSCE standards (grade 2). Also, all mixtures, except for mixtures added with viscosity agent, defoaming agent, and AE agent, do not meet a target air amount $4.5{\pm}1.5%$. High flowing Self-Compacting Concrete mixtureadded with defoaming agent shows that although time passes after its first mixture, its air amount reduces a little. Based on the experiment, we can know an optimal polymer amount to obtain the required flow performance

• Journal of Industrial Technology
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• v.21 no.B
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• pp.249-256
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• 2001

The purpose of this study was to remove the excessive air foaming which was produced in mixing the RSLMC(latex-modified concrete with rapid-setting cement) by choosing the best antifoam agent type. A series of RSLMM(latex-modified mortar with rapid-setting cement) experiments were carried out as a basic experiments for RSLMC with the main experimental variables such as antifiamer types(A, B, C, D), antifoamer contents(0, 1, 2, 3%), and latex contents(10, 15%). Air content test and compressive strength tests were carried out to measure the improved properties of RSLMM. SEM analysis, also, was carried to observe the formation of latex film. The results of RSLMM showed that the decrease of 50% air content was obtained by admixturing an antifoam agent by 1%. This made the strength enhanced and the workability be within the purposed. The best properties of compressive strengths was obtained at latex content of 15% and D antifoam agent of 1%. compressive strength increased about 32.6%. The analysis of SEM results no difference in a formation of later film.

• Proceedings of the Korean Institute of Surface Engineering Conference
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• 2018.06a
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• pp.33.2-33.2
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• 2018

현재 업계에서 사용 중인 대부분의 탈지제는 중온 및 고온에서 사용하는 제품이 많으며, 거품의 발생 또한 많으므로 소포제를 넣지 않고서는 사용이 불가능한 약품이 대부분이다. 탈지제 거품의 발생은 탈지제의 세정력을 높이기 위해 주로 사용되는 음이온성 계면활성제의 특성에 의해 나타나게 되는데, 본 연구에서는 음이온성 계면활성제를 사용하지 않음으로 기포의 발생을 억제하고, 동시에 상온에서 사용할 수 있는 약품을 개발함으로써 생산 공정에서의 원가절감과 신뢰성 및 양산성의 향상을 도모하는데 그 목적이 있다.

• Current Research on Agriculture and Life Sciences
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• v.12
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• pp.51-55
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• 1994

Pollen microspores isolated from peony anthers were cultured by agarose embedding method in the MS medium with 2,4-D(1mg/l) or phenylacetic acid(1, 10, 100mg/l), and without plant hormone. It was observed that pollen microspores cultured on hormone-free medium were directly developed into embryos. Callus formation was enhanced from microspores which were cultured on medium supplemented with 1mg/l PAA. Embryos were also formed from the calli transferred into the hormone-free medium.

• Journal of the Korean Applied Science and Technology
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• v.39 no.5
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• pp.720-726
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• 2022

The behavior changes of the lipid bilayer, induced by the hydroxybutyric-acid incorporation, were investigated with respect to each phase of the layer using fluorescence intensity change. Spherical phospholipid bilayers, called vesicles, were prepared using an emulsion technique. Only in the aqueous inside of the vesicles was encapsulated 8-Aminonaphthalene-1,3,6-trisulfonic-acid-disodium-salt(ANTS). p-Xylene-bis-N-pyridinium-bromide(DPX) was included as a quencher only outside of the vesicles. The fluorescence scale was calibrated with the ANTS-encapsulated vesicles in DPX-dispersed-buffer taken as 100% and the mixture of ANTS and DPX in the buffer as 0%. Hydroxybutyric-acid addition into the vesicle solution led the change in the bilayer. The change was found to be related to the phase of each layer according to the ratio of hydroxybutyric-acid to lipid. These results seem to depend on the stability of the vesicles, due to the osmotic and volumetric effects on the arrangement in both head-group and tail-group.

• Microbiology and Biotechnology Letters
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• v.17 no.1
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• pp.24-28
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• 1989

Effect of various fermentation parameter was investigated on the production of prednisolone by microbial $\Delta$'-dehydrogenation of hydrocortisone. The microbial conversion process was conducted by using pseudo-crystallo-fermentation techniques. The optimum temperature for the bioconversion process was found to be 35$^{\circ}C$. It was noted that the production rate of prednisolone was little affected within the initial pH range of 6.5-7.8, and also by the use of surfactant, Tween 80. Production rate of prednisolone was significantly reduced by the use of the antifoam agent, neolin. In a fermentor operation, however, large amount of antifoam agent should be used to remove foams generated by the high aeration rate, which resulted in n lower production rate of prednisolone than that from the shake flask experiment.

• Korean Journal of Food Science and Technology
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• v.10 no.2
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• pp.250-257
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• 1978

Functional additives such as methyl silicone, TBHQ and BHA/BHT have been evaluated for their effects on storage and frying stabilities of the vegetable salad oil. All test results strongly suggest that methyl silicone improved the frying stability and TBHQ improved the storage stability. BHA/BHT improved neither storage stability, nor frying stability of the vegetable saladoil. Based on the test results, it is recommended that methyl silicone in the range of $1.0{\pm}0.5ppm$ and TBHQ in the range of 200ppm be added to the vegetable salad oil for the improvement of frying and storage stabilities.

• KOREAN JOURNAL OF CROP SCIENCE
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• v.57 no.4
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• pp.317-323
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• 2012

For the establishment of an efficient embryogenesis from microspore culture in Brassica napus L. domestic cultivar 'Tammiyuchae', four different factors affecting microspore embryogenesis and plantlet regeneration were investigated. The highest embryogenesis rate was achieved when microspores at late uninucleate to early binucleate stage were isolated from flower buds with a length of 3.0~3.5 mm. On average, 388 embryos generated from 1 ml of microspores media. The highest number of embryos was obtained when microspores were subjected to $32.5^{\circ}C$ for 2 days. Embryogenesis of 'Tammiyuchae' was increased with increasing microspore culture density up to about $5{\times}10^4ea/mL$. Gradually higher culture density repressed embryogenesis of microspores. Regeneration rate of shoots from microspore-derived embryos was observed in MS solid medium supplemented with $0.5mg{\cdot}L^{-1}$ NAA and $1.0mg{\cdot}L^{-1}$ BA, and grew well in MS solid medium without plant growth regulators.

• Journal of the Korean Applied Science and Technology
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• v.27 no.3
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• pp.223-232
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• 2010

The effects of HLB value of nonionic mixed surfactants on the stability and antifoaming ability for silicon oil type emulsions were studied. To obtain a stable silicone emulsions, a higher HLB values and higher content of surfactants were preferred. To obtain a good antifoaming ability, however, a lower HLB value (more hydrophobic) and a lower content of the surfactants were preferred. It was observed, at lower HLB values(8 or 9), that the silicone oil drops were spreaded on the foam surface and effectively reduced the surface tension. And the spreading phenomena presumably acted as an antifoaming mechanism. Therefore, a higher hydrophobicity of the silicone oil emulsion resulted in a higher ability of antifoaming action.

• Journal of the Korean Recycled Construction Resources Institute
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• v.6 no.4
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• pp.304-310
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• 2018

The aim of the research is to provide possibility of quality controlling by rheological properties for lightweight foamed concrete. The lightweight foamed concrete achieves its low density by containing air bubbles (foam) produced during the mixing process. Therefore, containing foamed volume during setting period is critical for the securing the performance as an insulating material. In this research, regarding foam collapse during the setting period, rheolgocial properties of fresh state lightweight foamed concrete were assessed to get its relationship with volume stability, or foam stability. For the experiment regarding foaming factors including mixing time, mix design of contents for materials, rheological properties of fresh state lightweight foamed concrete were tested with its density and settling depth. Based on the settling depth with various factors, relationship with rheological properties was analyzed, and especially, close relationship of plastic viscosity and settling depth was found. Therefore, from the results of this research, it is considered to contribute on suggesting a new approach of quality controlling for lightweight foamed concrete using rheological test method.