• Clean Technology
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• v.25 no.2
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• pp.114-122
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• 2019

The synthesis of bio polyol from renewable resources has attracted attention in recent years. In particular, it is important to take advantage of bio polyols in the synthesis of polymers. In this study, a series of dimethylformamide (DMF) based polyurethanes were synthesized using polycarbonate polyol/bio polyol (PO3G: polytrimethylene ether glycol prepared from 1, 3-propanediol produced by fermentation from corn sugar), methylene diphenyl diisocyanate (MDI) and 1,4-butandiol (BD). The properties of prepared polyurethane films and the cell structure of wet type artificial leather were investigated. As the bio polyol content increased, the tensile strength of polyurethane films decreased, however, the elongation at break increased significantly. As a result of thermal characteristics analysis, the glass transition temperature of polyurethanes increased when increasing the content of polycarbonate polyol. As a result of comparing the cell characteristics of wet type artificial leathers prepared in this study, it was found that the number and uniformity of cells formed in the artificial leather samples increased when increasing the content of polycarbonate polyol in polycarbonate polyol/bio polyol. From these results, it was found that DMF-based polyurethane containing an appropriate amount of bio polyol could be used for wet type artificial leather. The bio textile analysis system according to ASTM standard was used to measure the bio carbon content of polyurethane. The content of bio carbon increased proportionally with the increase of bio polyol content used in polyurethane synthesis.

• Fashion & Textile Research Journal
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• v.23 no.6
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• pp.844-851
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• 2021

Due to the increase in consumers' interest about well-being, interest in eco-friendly products has been increasing due to the harmful effects of various harmful substances contained in textile products and environmental issues. As a result, natural dyes of less potential risk than synthetic dyes and digital textile printing(DTP) textile products with less environmental pollution are drawing attention. However, due to the lack of evaluation criteria for DTP textile products with natural ink and the nature of many colors are stacked layer by layer for dying, the need for simultaneous analysis is emerging. To evaluate whether the natural dye is derived from natural ingredients, the biocarbon content is analyzed. However, in the case of ink made using natural dyes and DTP textile products using natural ink, it is difficult to analyze the biocarbon content due to the limitation of the presence of a small amount of dye contained therein. In this study, we were shown the possibility of natural derived verification by cross-checking the analytes of natural dyes (Persicaria tinctoria, an indigo dye; Dactylopius coccus, a light red; and Curcum longa L., i.e., turmeric) and natural ink with HPLC-MS/MS. The coefficient of determination was 0.999 or higher, the limit of quantification was 0.647-3.664 ㎍/L and a %RSD of each indicator material was less than 10. Then, the extraction amount of natural dyes for five patterned fabrics was analyzed.

• Korean Chemical Engineering Research
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• v.47 no.6
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• pp.655-668
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• 2009

The principle and applications of quartz crystal sensors based on the three basic concepts for mass, viscosity, and viscoelastic changes are reviewed. In the general discussion the basic principle of quartz crystal and realization of a resonant frequency-resonant resistance diagram are described in detail. As examples of their applications, gas sensing with a carbon-coated quartz crystal, determination of the blood coagulation factor, an electrochemical analysis and crystallization analysis are reported. The possibility of developing new biosensors and chemical sensors is discussed on the basis of these results.

• Journal of Korea Foresty Energy
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• v.22 no.2
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• pp.54-59
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• 2003

Recently, densified pellet fuel from wood biomass is widely used at North America and Europe as a regenerable and clean carbon neutral bioenergy. High-pressure compaction of sawdust of Hyunsasi-poplar (Populus alba ${\times}$ P. glandulosa) to form a densified fuel was studied. Calorific and elemental analysis were carried out to assess Hyunsasi-poplar clones as fuels. Hot-press process was adopted for compaction of sawdust and compaction was performed under temperature from 100 to 180$^{\circ}C$, at pressure of 250 to 1000 kgf/$\textrm{cm}^2$, and for 2.5 to 10 minutes. Densified fuels were evaluated by its oven-dry density and fines after 5-minute shaking test. The target density and fines of densified fuels were over 1.2 g/$\textrm{cm}^2$ and below 0.5%, respectively. When the press-temperature is over 160$^{\circ}C$, densified fuels with density eve. 1.2 g/$\textrm{cm}^2$ and with fines below 0.5% can be produced. And the pressure over 750 kgf/$\textrm{cm}^2$ was effective for this production. It was found that the optimum press condition for preparation of densified fuel was 180$^{\circ}C$ -1000 kgf/$\textrm{cm}^2$ minutes.

• Analytical Science and Technology
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• v.21 no.2
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• pp.129-134
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• 2008

Cyclic voltammetry (CV) and square wave stripping voltammetry (SW) analysis of hexahydro-1,3,5-trinitro-1,3,5-triazine (RDX) using the double-stranded ds calf thymus (DNA) mixed in carbon nanotube paste electrode (PE) were provided. The optimum analytical conditions were determined and the peak potential was 0.2 V vs. Ag/AgCl. The linear working ranges of CV (50-75 ug/L) and SW (5-80 ng/L) were obtained. The precisions of RSD in the 10 ug/L was 0.086% (n=15) and the detection limit was 0.65 ng/L ($2.92{\times}10^{-12}M$) (S/N=3) with 300 s adsorption time at the optimum condition. The method was used to determine the presence of explosive chemicals in contaminated soil samples.

• Science of Emotion and Sensibility
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• v.24 no.4
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• pp.129-138
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• 2021

This study aimed to determine the effects of the shape and attachment position of stretchable textile sensors coated with carbon nanotube on their performance when used to measure children's joint movements. Moreover, the child-safe requirements for fabric motion sensors are established. The child participants were advised to wear integrated clothing equipped with the sensors of various shapes (rectangular and boat-shaped) and attachment positions (at the knee and elbow joints or 4 cm below the joints). The voltage change induced by the elongation and contraction of the fabric sensors was determined for arm and leg flexion-extension motions at 60 deg/s (three measurements of 10 repeats each for 60°and 90°angles, for a total of 60 repetitions). Their dependability was determined by comparing the fabric motion sensors to the associated acceleration sensors. The experimental results indicate that the rectangular-shaped sensor affixed 4 cm below the joint is the most effective fabric motion sensor for measuring children's arm and leg motions. In this study, we designed a textile sensor capable of tracking children's joint motion and analyzed the sensor shape and attachment position on motion sensing clothing. We demonstrated that flexible fabric sensors integrated into garments may be used to detect the joint motions of the human body.

• Analytical Science and Technology
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• v.29 no.1
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• pp.35-42
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• 2016

A new nano-composite carbon ink for the development of disposable dopamine (DA) biosensors based on screen-printed carbon electrodes (SPCEs) is introduced. The method developed uses SPCEs coupled with a tyrosinase modified nano-composite carbon ink. The ink was prepared by an “in-house” procedure with reduced graphene oxide (rGO), Pt nanoparticles (PtNP), and carbon materials such as carbon black and graphite. The rGO-PtNP carbon composite ink was used to print the working electrodes of the SPCEs and the reference counter electrodes were printed by using a commercial Ag/AgCl ink. After the construction of nano-composite SPCEs, tyrosinase was immobilized onto the working electrodes by using a biocompatible matrix, chitosan. The composite of nano-materials was characterized by X-ray photoelectron spectroscopy (XPS) and the performance characteristics of the sensors were evaluated by using voltammetric and amperometric techniques. The cyclic voltammetry results indicated that the sensors prepared with the rGO-PtNP-carbon composite ink revealed a significant improvement in electro-catalytic activity to DA compared with the results obtained from bare or only PtNP embedded carbon inks. Optimum experimental parameters such as pH and operating potential were evaluated and calibration curves for dopamine were constructed with the results obtained from a series of amperometric detections at −0.1 V vs. Ag/AgCl. The limit of detection was found to be 14 nM in a linear range of 10 nM to 100 µM of DA, and the sensor’s sensitivity was calculated to be 0.4 µAµM⁻¹cm⁻².

• Journal of the Korean Wood Science and Technology
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• v.46 no.1
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• pp.17-28
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• 2018

In this study, catalytic activation using sulfuric acid lignin (SAL), the condensed solid by-product from saccharification process, with potassium hydroxide at $750^{\circ}C$ for 1 h in order to investigate its potential to nanoporous carbon In this study, catalytic activation using sulfuric acid lignin (SAL), the condensed solid by-product from saccharification process, with potassium hydroxide at $750^{\circ}C$ for 1 h in order to investigate its potential to nanoporous carbon material. Comparison study was also conducted by production of activated carbon from coconut shell (CCNS), Pinus, and Avicel, and each activated carbon was characterized by chemical composition, Raman spectroscopy, SEM analysis, and BET analysis. The amount of solid residue after thermogravimetric analysis of biomass samples at the final temperature of $750^{\circ}C$ was SAL > CCNS > Pinus > Avicel, which was the same as the order of activated carbon yields after catalytic activation. Specifically, SAL-derived activated carbon showed the highest value of carbon content (91.0%) and $I_d/I_g$ peak ratio (4.2), indicating that amorphous large aromatic structure layer was formed with high carbon fixation. In addition, the largest changes was observed in SAL with the maximum BET specific surface area and pore volume of $2341m^2/g$ and $1.270cm^3/g$, respectively. Furthermore, the adsorption test for three kinds of organic pollutants (phenol, 2,4-Dichlorophenoxyacetic acid, and carbofuran) were conducted, and an excellent adsorption capacity more than 90 mg/g for all activated carbon was determined using 100 ppm of the standard solution. Therefore, SAL, a condensed structure, can be used not only as a nanoporous carbon material with high specific surface area but also as a biosorbent applied to a carbon filter for remediation of organic pollutants in future.