• Applied Biological Chemistry
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• 제2권
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• pp.45-52
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• 1961

The decomposition of malathion in dust for mulations prepared from four Korean tales as carriers during storage period has been studied. Amberlite CG-120, a cation exchange resin . which has higher cation exchange capacity than tales, was also used as a carrier in hope of finding out the effect of nagative charge upon the decomposition of malathion. Besides the original talc powders obtained directly from the mines, the hydrogen ion saturated forms were also used as carriers for comparisonal study. The saturated ions for the resin were hydrogen, sodium and magnesium. As the physical properties of the tales, colloid content, water adsorption capacity, PH, specific surface, phosphate fixing capacity and exchangeable canons were determined, and these properties were correlated with the amount of the decomposition. Following results were obtained from the experiment. 1. The malathion in the talc in dust was found to decompose around 10-15% ofthe total withina month. About 50% of the decom position that took place after a month was found to occur within a week. 2. The resin which has higher cation exchange capacity than the tales was highly effective in the decomposition of malathion compared with the tales. 3. In every case the saturation of the exchange complexes with hydrogen ion greatly accelerated the decomposition of malathion. 4. The most highly correlated physical properties with the decomposition were colloid content and specific surface of the tales. 5. The water adsorption and phosphate fixing capacities of the tales were found not to correlate with the amount of malathion decomposed. From the experimental results it was concluded that the active negative spots on the colloidal tales or the resin attract the electropositive phosphorus atom in a malathion molecule thereby inducing the decomposition easier. The presence of hydrogen ion nearby might cause a catalytic effect in the decomposition of malathion.

• 제어로봇시스템학회:학술대회논문집
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• 제어로봇시스템학회 2002년도 ICCAS
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• pp.94.5-94
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• 2002

The current study of complex dynamical networks is pervading all kinds of sciences today, ranging from physical to biological, even to social sciences. its impact on modern engineering and technology is prominent and will be far-reaching. Typical complex dynamical networks include the World Wide Web, the Internet, various wireless communication networks, meta-bolic networks, biological neural networks, social connection networks, scientific cooperation and citation networks, and so on. Research on fundamental properties and dynamical features of such complex networks have become overwhelm ing. This talk will provide a brief overview of some basic concepts about com plex dynamical netwo...

• 대한의용생체공학회:의공학회지
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• 제15권3호
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• pp.341-346
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• 1994

To develop an artificial bone substitute that is gradually degraded and replaced by the regenerated natural bone, the authors designed a composite that is consisted of calcium phosphate and collagen. To use as the structural matrix of the composite, collagen was purified from human umbilical cord. The obtained collagen was treated by pepsin to remove telopeptides, and finally, the immune-free atel- ocollagen was produced. The cross linked atelocollagen was highly resistant to the collagenase induced collagenolysis. The cross linked collagen demonstrated an improved tensile strength.

• 농업과학연구
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• 제23권2호
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• pp.233-241
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• 1996

The mechanical properties of biological materials depend on numerous factors. The majority of these relationships are still unknown today, especially with regard to their quantitative characteristics. The reason is that biological materials constitute biomechanical systems of very complex construction, whose behavior cannot be characterized by simple physical constants, as for example can that of engineering materials. The objectives of this investigation were to determine the compression creep and recovery properties of rice stalks at various levels of applied load The compression creep and recovery behavior of the rice stalk could be predicted precisely by rheological model which approached closely to the measured values. But the coefficients of the Burgers recovery model were different from those of the creep model. The Steady state creep behavior occurred at the higher level of force and the logarithmic creep behavior occurred at the lower level of force. The mechanical model being expected the creep behavior in relation with the level of applied load, which was well explained that the rice stalk might be visco-elastic material.

• 펄프종이기술
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• 제38권3호
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• pp.72-78
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• 2006

The extraction properties of the biological waste originated from the Tobacco industry were evaluated. The biological waste have been recycled and transformed into a valuable material, so called a reconstituted tobacco sheet(Recon) by the papermaking process. In this process, The mechanical extraction process, which divides the mixed raw material slurry into the soluble stock and the insoluble stock, could affect not only the quality of final Recon product but also the productivity of whole Recon making process. This study investigated the effects of the extraction process on the slurry properties in detail. In order to quantify the amounts of the solubles which resided in the insoluble fibers, the washing treatment of the stock before and after squeezing process was applied. The amounts of the residual solubles showed little changes according to each stage of the extraction process. The fractionation of the slurry showed the difference in the amount of soluble in the stock depending on the size of the biological waste. After the extraction process, the bigger size fiber portion contained about 19%(by weight) in soluble after pressing but the smaller size fiber portion 9% in soluble. The fractionation ratio of the stocks also was changed by the screw press process, which could demonstrate the physical effects of the mechanical extraction.

• Journal of Pharmaceutical Investigation
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• 제32권3호
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• pp.191-197
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• 2002

Polymer based physical mixtures or solid dispersions containing solubilizing compositions[OA, tween80 and SLS] were prepared using a spray-dryer. Lovastatin(LOS), simvastatin(SIMS), aceclofenac(AFC) and cisapride(CSP) were selected as poorly water-soluble drugs. Dextrin, poly(vinylalcohol) (PVA), poly(vinylpyrrolidone)(PVP) and polyethylene glycol(PEG) were chosen as solubilizing carriers for solid dispersions. The solid dispersions containing solubilizing compositions without drug were prepared without using organic solvents or tedious changes of formulation compositions. This system could be used to quickly screen the dissolution profiles of poorly water-soluble drugs by simply mixing with drugs thereafter. In case of solid dispersion containing drug, organic solvent systems could be used to solubilize model drugs. The dissolution rates of the drugs were higher when mixed with drug and solid dispersions containing solubilizing compositions. However, solid dispersions of LOS, AFC, and CSP simultaneously containing drug and solubilizing compositions in organic solvent systems were more useful than physical mixtures of drug and solid dispersions without drug except SIMS. Based on solubilizing capability of polymer based physical mixtures in gelatin hard capsules, optimal solid dispersion system of poorly water-soluble drugs could be formulated. However, it should be noted that dissolution rate of poorly water-soluble drugs were highly dependent on drug properties, solubilizing compositions and polymeric carriers.

• 유기물자원화
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• 제2권2호
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• pp.77-88
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• 1994

하수오니를 첨기한 토양에서 Orchardgrass 유식물체의 생육과 토양의 이화학적 성질의 변화에 미치는 영향을 조사하였고, 식물체 부위에 집적된 중금속의 농도와 토양 잔류 중금속 농도를 분석하여 유기질 비료자원으로서 하수오니의 이용가능성을 검토하였다. Orchardgrass 유식물체의 생물학적 수량은 하수오니의 혼합비율이 높아짐에 따라서 증가되었고, 하수오니의 혼합비율이 높아짐에 따라서 토양의 이화학적 성질이 크게 개선되었다. Orchardgrass 유식물체는 개체당 경수와 1경중의 증가에 의하여 지상부 건물중이 증가되었고, 지상부 건물중의 증가에 의하여 생물학적 수량이 많아졌다. 식물체내의 전질소량과 생물학적 수량과는 2차곡선적인 증가경향을 나타내어, 하수오니중의 전질소량이 식물체의 생육에 미치는 영향이 컸다. 중금속의 종류에 따라서 식물체내에 집적되는 부위가 달라졌으며, 토양 잔류 중금속중에서 납(Pb)은 하수오니 60% 이상의 혼합비율에서 허용규제치(50ppm) 이상의 높은 농도를 나타내었다.

• Macromolecular Research
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• 제16권2호
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• pp.85-102
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• 2008

The development of reliable synthetic routes to polymer nanomaterials with well-defined size and morphology is a critical research topic in contemporary materials science. The ability to generate nanometer-sized polymer materials can offer unprecedented, interesting insights into the physical and chemical properties of the corresponding materials. In addition, control over shape and geometry of polymer nanoparticles affords versatile polymer nanostructures, encompassing nanospheres, core-shell nanoparticles, hollow nanoparticles, nanorods/fibers, nanotubes, and nanoporous materials. This review summarizes a diverse range of synthetic methods (broadly, hard template synthesis, soft template synthesis, and template-free synthesis) for fabricating polymer nanomaterials. The basic concepts and significant issues with respect to the synthetic strategies and tools are briefly introduced, and the examples of some of the outstanding research are highlighted. Our aim is to present a comprehensive review of research activities that concentrate on fabrication of various kinds of polymer nanoparticles.

• Macromolecular Research
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• 제16권1호
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• pp.36-44
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• 2008

A series of polysiloxanes containing alkylsulfonyl side groups were synthesized using a polymer analogous reaction beginning from poly(methylhydrosiloxane) and the corresponding olefins. These polymers showed a mesomorphic behavior with smectic liquid crystalline phases. The chemical and physical properties of these polymers were examined using nuclear magnetic resonance spectroscopy, gel permeation chromatography, differential scanning calorimetry, optical polarizing microscopy, and X-ray diffraction.

• 한국유기농업학회지
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• 제19권spc호
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• pp.218-221
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• 2011

To improve the soil properties of physical and microbial community rice bran and wood charcoal were applied in the continuously cultivated plastic film house soil. Soil physical properties were improved by application of rice bran and charcoal compared to chemical fertilizer application (control) by 8~14% in bulk density and 5~9% in soil porosity. Changes in the biological ratio indexes of fatty acids in the soils were detected depending on the inputted materials. Especially in application of rice bran including mixture with charcoal, much more fungi and less bacteria were detected and the ratio of fungi to bacteria was increased, suggesting the more organic carbon metabolically active in these treatments. The high ratio of aerobe to anaerobe suggested the better aerobic conditions were in the soil inputted wood charcoal. From these results, it is important and possible to select some materials for the organic pepper cultivation, which may improve the poor condition soil.