• Proceedings of the Korean Nuclear Society Conference
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• 1999.05a
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• pp.394-394
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• 1999

• Proceedings of the Materials Research Society of Korea Conference
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• 1993.05a
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• pp.141-142
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• 1993

• Journal of the Korean Society of Clothing and Textiles
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• v.29 no.7 s.144
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• pp.997-1007
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• 2005

The textile finishing methods utilizing chitosan have been mostly focused on the applications in the improvement of the dyeing of cotton fabrics, or the improvement of hand of the cotton or wool fabrics. On the other hand, it Is difficult to find the application examples in the synthetic fiber fabrics including polyester and nylon fabrics. The aim of this study is to improve the stiffness and the poor wash fastness of the fabrics treated only with chitosan. We tried to improve the softness by employing chitosan and polyurethane mixture solution and to prevent the detachment of the chitosan from the fabric. The treatment was applied to cotton, polyester, and nylon fabrics. The change of the properties of the treated fabrics were investigated. The optimum finishing condition was sought by changing the mixture ratio of the chitosan/PU(polyurethane) solutions. The adjusted ratios of the chitosan/PU solutions were 1 : 0, 1 : 0.25, 1 : 0.5, and 1 : 2 during the mixture solution preparation. Using the KES(Kawabata Evaluation System), the physical and mechanical properties of the finished fabric specimens were analyzed, and hand values of the specimens were calculated through the use of translational formulas. According to the chemical composition of the fibers, chitosan solution or chitosan/PU mixture exhibited wide range of coating effect. Since the chitosan acid solution has high polarity, the bonding force with the cotton fibers is high. By the appropriate addition of PU in the chitosan treatment of cotton, KOSHI and HARI values of the fabric improved. The air permeability of the chitosan/PU treated cotton fabric specimen improved, resulting in the highest value at the mixture of chitosan : PU=1:0.25.

• Journal of the Korean Chemical Society
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• v.46 no.3
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• pp.233-240
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• 2002

In this work, the cure kinetics and rheological and mechanical properties of diglycidylether of bispheonol A (DGEBA, EP)/polyurethane (PU) blends were investigated. The 1 wt% N-benzylpyrazinium hexafluoroantiminate (BPH) was used as a latent thermal catalyst. Latent properties were performed by measurement of the conversion as a function of reaction temperature using DSC. And the rheological properties of the blend systems were investigated under isothermal conditions using a rheometer. Crosslinking activating energies (Ec) were also determined from the Arrhenius equation based on gel time and curing temperature. The impact strengths were measured as mechanical properties of the casting specimens. The BPH in the blend systems could be an excellent latent thermal catalyst without any co-initiator. The rheological results showed that Ec was highest when PU content was 30 wt% which was in good agreement with the impact strengths. This was probably due to the intermolecular hydrogen bonding between the hydroxyl group in PU and EP, resulting in increasing the crosslinking density.

• Journal of Environmental Science International
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• v.15 no.6
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• pp.513-525
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• 2006

In recent decades, biofiltration has been widely accepted for the treatment of contaminated air stream containing low concentration of odorous compounds or volatile organic compounds (VOCs). In this study, conventional biofilters packed with flexible synthetic polyurethane (PU) foam carriers were operated to remove toluene from a contaminated air stream. PU foams containing various amounts of pulverized activated carbon (PAC) were synthesized for the biofilter media and tested for toluene removal. Four biofilter columns were operated for 60 days to remove gaseous toluene from a contaminated air stream. During the biofiltration experiment, inlet toluene concentration was in the range of 0-150 ppm and EBRT (i.e., empty bed residence time) was kept at 26-42 seconds. Pressure drop of the biofilter bed was less than 3 mm $H_2O/m$ filter bed. The maximum removal capacity of toluene in the biofilters packed with PU-PAC foam was in the order of column II (PAC=7.08%) > column III (PAC=8.97%) > column I (PAC=4.95%) > column IV (PAC=13.52%), while the complete removal capacity was in the order of column II > column I > column III > column IV. The better biofiltration performance in column II was attributed to higher porosity providing favorable conditions for microbial growth. The results of biodegradation kinetic analysis showed that PU-PAC foam with 7.08% of PAC content had higher maximum removal rate ($V_m$=14.99 g toluene/kg dry material/day) than the other PU-PAC foams. In overall, the performance of biofiltration might be affected by the structure and physicochemical properties of PU foam induced by PAC content.

• Journal of Radiation Protection and Research
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• v.16 no.1
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• pp.43-52
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• 1991

A comparison study is performed on dose assessment programs including DOSE, LIMCAL, and PABLM, DOSE is a program developed for preliminary safety assessments of the low- and intermediate- level radioactive waste disposal, and the others are existing programs applicable to similar calculations. The results show acceptable agreement within an order of magnitude(mrem/yr) except for C-14 and Pu-239. PABLM results higher dose for C-14 while lower value for Pu-239 in comparison with those from DOSE or LIMCAL. It is found that the discrepancy in C-14 is due to difference in transport model introduced and that in Pu-239 is from the different value of dose conversion factor to each program.

• Science of Emotion and Sensibility
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• v.19 no.3
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• pp.43-50
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• 2016

The uniform nanofibers of polyurethane with different contents of Juniperus Chinensis extracts were successfully prepared by electrospinning method. Polyurethane is widely used as functional polymers in the industrials, medical field as their properties can be tailor-made by adjusting their compositions. Juniperus Chinensis has been reported for anti-tumor, anti-bacterial, anti-fungal, and anti-viral activities. PU/Juniperus Chinensis extracts composite nanofibers were produced at different Juniperus Chinensis extracts concentrations (0.25, 0.5, 1, 1.5wt.%). The effects of the major parameters in electrospinning process such as tip to collector distance (TCD), voltage, polymer concentration on the average diameter of electrospun nanoweb were investigated. As results, 12wt% PU solution concentration, 8kV applied voltage and 15cm tip to collector distance were identified as optimum conditions for electrospinning the composite nanofibers. The diameter and morphology of the nanocomposite nanofibers were confirmed by a scanning electron microscopy (SEM). The resulting fibers exhibited a uniform diameter ranging from 435nm~547nm. It has been found that the average diameters of fibers decreased by the adding of Juniperus Chinensis extracts. These nanowebs can be used for medical materials, protective clothing, and antimicrobial filters.

• Polymer(Korea)
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• v.31 no.4
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• pp.308-314
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• 2007

A composite film of polyurethane(PU)-graft-poly(acrylic acid) (PAAc)/polyaniline (PU-g-AAc/PANI) was successfully fabricated for the purpose of adding conductivity on the surface of a general purpose polymer and improving adhesive property between the general purpose polymer and conducting polymer layer. The results from ATR-FTIR and XPS analyses also supported the successful synthesis of the composite film by showing characteristic peaks for every step. A low surface resistivity of $2{\times}10^3\;ohm/sq$ proved the surface conductivity of synthesized PU-g-AAc/PANI film and the surface resistance decreased with increasing the amount of grafted AAc, which acted as a dopant for PANI film.

• Journal of Korean Medical classics
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• v.12 no.2
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• pp.166-174
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• 1999

Meridians are often defined as passway of Ki and Blood or something that can control funtions of the body. It is true but I think meridians have something more than that. Meridians are not just passway of Ki and Blood, rather they receive Ki from outside and transform it into Essence-Ki(精氣). If we draw a line in a body, we have Chang-Pu inside and meridians outside. Chang-Pu whim is inside our body hold Essence-Ki and manipulate it. These Chang-Pu also have variation of Ki accumulation-Tai-Yang, Soyang, T'ae$\breve{u}$m, Soum. Nevertheless, their gradients are not great so Ki flow among them are not great either. If there are much Ki flow in our body there will be much Ki consumption resulting in exhaustion of Essence-Ki, which is very hard to acquire. Therefore Chang-Pu keeps less gradient by not moving Ki a lot to preserve Essence-Ki. Chang-Pu, inside, are suitable for storing Ki while meridians, outside, are for producing Ki. Meridinas have great difference in Ki accumulation so there are great flow of Ki. This nature is suitable for producing Ki. For example, roots and limbs of a tree don't have much gradient in Ki. They are concentrated and their shape are not very distinct. On the other hand, leaves are wide and it's easy to tell front from back. It means their Ki gradient is great and their Ki flow is also great. Therefore they suitable for producing Ki. Just like this, meridians in our body are suitable for producing Ki. Areas that meridians cover are much wider than that of Chang-Pu. Four limbs and surface of our body are very distinctive. Ulnar side is high in Ki accumulation but is small in volume so it's better to store Ki there. Radial side is low in Ki accumulation but big in volume so it's better to receive and consume Ki there. Meridians are deeply involved in producing and storing Ki.

• Microbiology and Biotechnology Letters
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• v.32 no.3
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• pp.265-270
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• 2004

To select a promising technologies for removal of odorous gases emitted from a wastewater pump station, four methods such as activated carbon (A/C) adsorption, chemical absorption (acid and alkali scrubber), and two biofilters (polyurethane (PU) and worm cast) were investigated. The average odor removal efficiencies in the PU biofilter and A/C column was over 98%, but in a worm cast biofilter and chemical absorption were below 60-80%. The removal efficiency of PU biofilter was very stable (about 98-99%) in the range of retention times of 4-36s, and a maximum elimination capacity was $1.6${\times}$10^{ 7}$ $OUm^{-3}$$h^{-1}$ Deodorization costs for an activated carbon adsorption and a biofiltration method were investigated. With increasing odor intensity, the operating cost of the A/C column increased linearly, but the operating cost of the biofilteration increased slightly. The capital cost in a biofilter is about two times higher than that in an A/C column, but the operating cost is very lower than that of in A/C column. In conclusion, the biofiltration was evaluated one of the most promising technologies to control odor in a wastewater pump station.