• Journal of Korea Technical Association of The Pulp and Paper Industry
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• v.48 no.1
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• pp.53-60
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• 2016

Abiotic-stressed tobacco stems as a non-wooden biomass were analyzed for their chemical characteristics. Light-stressed tobacco stems (LST) have a relatively high nitrogen concentration, much more extractive content, and a similar amount of lignin and higher contents of acid sugars than those of Non stressed tobacco (NST). It also has low cellulose crystallinity and a high degree of condensation. Guaiacyl units having a lower molecular weight distribution consist of rich lignin. Tension stressed tobacco (TST) growth differentiation under tensile stress was significantly different between normal tissue and cell walls, with the exception of the slightly higher cellulose crystallinity observed for.

• Journal of Korea Technical Association of The Pulp and Paper Industry
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• v.45 no.5
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• pp.56-63
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• 2013

In this study, paper mill applicability of two kinds of cotton pulps which have different initial freeness, fiber length and intrinsic fiber strength were investigated. Basic properties such as CED viscosity, fiber length, and crystallinity of major two kinds of cotton pulps were analyzed, and beatability of cotton pulps and physical properties of handsheet made from two kinds of cotton pulps were compared. Laboratory beating was performed at different refining conditions such as refining loads and freenesses. Relationship between beating degree and physical properties of handsheet were compared to seek optimum condition of refining for different cotton pulps application to paper mill.

• Journal of the Korean Society of Industry Convergence
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• v.2 no.1
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• pp.27-33
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• 1999

Effects of spinning speed and draw ratio on structure and mechanical properties of PP filament. A The crystalline structure and mechanical properties of uniaxially deformed polypropylene filament has been examined by XRD, birefringence, UTM and density method. Uniaxially deformed PP filament was prepared of various spinning speeds (300, 600, 900m/min.) and draw ratio(x2, x3, x4). From the results of these studies, it found the following facts. Firstly, it was found that the crystallinity and crystallite size (110plane) of the samples were increased with increasing of spinning speed and draw ratio, especially, it was rapidly increased between as spun yarn and 2 times draw ratio. Secondly, birefringence value was increased with increasing of spinning speed and draw ratio. The mechanical properties of initial modulus, tensile strength were increased with increasing of spinning speed and draw ratio also, but the degree of elongation decreased as spinning speed and draw ratio.

• Journal of Korea Foresty Energy
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• v.20 no.2
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• pp.20-27
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• 2001

An effective method for production of glucose was developed using enzymatic hydrolysis of Suwon poplar by the cellulase. Enzymatic hydrolysis of wood is the reaction to produce glucose from wood using enzyme which derives from microorganism. Glucose can be transferred easily to ethanol by fermentation. Ethanol is the starting material for producing acetone, butanol, citric acid and lactic acid. The mechanism of the enzymatic hydrolysis of cellulose are reasonably explained in terms of the sequential action of three different types of enzymes, endo-cellulase, ex-cellulase, and $\beta$ -glucosidase. The goal of this work was to investigate the cellulose hydrolysis pretreated polar with various concentration NaOH, the crystallinity of cellulose, lignin contents and the degree of hydrolysis.

• The Journal of Engineering Research
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• v.3 no.1
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• pp.235-242
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• 1998

Hydrosilylation and vromination of vacterial poly($\beta$-Hydroxyalkanoates) containing carbon-carbon double bond or triple bond were carried out. The produced polymers were characterized by IR-spectroscopy and differential scnning calorimetry. Hydrosilylated polymers were characterized crystallinity while brominated polymers had lower degree of crystallinity with increased glass transition temperatures. Mixing polymers containing carbon-carbon triple bonds with Co(II) AND Pt(II) resulted crosslinked polymers.

• Polymer(Korea)
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• v.24 no.1
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• pp.113-123
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• 2000

Poly(p-hydroxybenzoate) (PHB)/poly(ethylene terephthalate) (PET) 8/2 thermotropic liquid crystalline copolyester, poly(ethylene 2,6-naphthalate) (PEN) and PET were mechanically blended to obtain the pseudo liquid crystalline (LC) phase of ternary blends. The torque values of blends with increasing PHB content were abruptly decreased above 40 wt% of PHB content, because the melt viscosity of ternary blends decreased. Tensile strength and initial modulus of blends containing above 30 wt% PHB were improved with increasing PHB content. Tensile strength and modulus of fiber were increased with PHB contents and take-up speed. Degree of transesterification and randomness of blends were increased with blending time. The blend of 40 wt% PHB was shown pseudo LC phase in the polarized optical photographs. Crystallinity of PHB/PEN/PET ternary blend were increased with PHB content.

• 전기의세계
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• v.23 no.5
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• pp.54-60
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• 1974

Proposals were mode on how to differentiate radiation effects in morphological phases of polyethylene and discussions were developed with the results obtained on a low density polyethylene, SOCAREX, specified by number average molecular weight; overbar Mn=5,400, density; 0.92, and degree of branch; 3.4/100 carbon atom, which was irradiated to Co$^{60}$ .gamma. ray at the dose rate of 0.5 Mrad/hr in ambient temperature under the pressure of 10$^{-5}$ Torr. or 1 atm. respectively. The effect to crystalline phase in possibly deduced from dose dependent variation of relative area between (110) and (200) peaks on X ray diffraction spectrum and that, the effects to amorphous phase can be understood through dose dependent relaxation behaviours of .betha. peak on internal friction characteristics of the specimen. The results obtained thus far indicate that, in crystalline phase, relative crystallinity shows a rather rapid decrease up to 20 Mrad with increasing dose, however, little change of crystallinity can be observed in the region between 20-200 Mrad, and degradation appears to be more predominant than crosslinking up to 60 Mrad. While in amorphous phase the indication also shows that degradation is only predominant up to 20 Mrad. Furthermore several correlations can be seen with amenable explanation between dose dependent behaviours observed in both phases.

• Macromolecular Research
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• v.12 no.1
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• pp.112-118
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• 2004

With the goal of enhancing the creep resistance of ultra-high molecular weight polyethylene (UHMWPE), we performed gamma irradiation and post-irradiation annealing at a low temperature, and investigated the crystalline structures and mechanical properties of the samples. Electron spin resonance spectra reveal that most of the residual radicals are stabilized by annealing at 100$^{\circ}C$ for 72 h under vacuum. Both the melting temperature and crystallinity increase after increasing the dose and by post-irradiation annealing. When irradiated with the same dose, the quenched sample having a higher amorphous fraction exhibits a lower swell ratio than does the slow-cooled sample. The measured tensile properties correlate well to the crystalline structure of the irradiated and annealed samples. For enhancing creep resistance, high crystallinity appears to be more critical than a high degree of crosslinking.

• KOREAN JOURNAL OF CROP SCIENCE
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• v.68 no.2
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• pp.35-46
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• 2023

The transplanting period limit considering the rice yield in the Dague region, the inland plains of Gyeongsangbuk-do, was estimated to be July 15^th for early and mid-maturing rice and July 5^th for mid-late maturing rice. However, as the transplanting time was delayed, the characteristics of rice starch changed significantly. In the case of early and mid-maturing rice varieties, the starch granule size increased as the transplanting time was delayed; the opposite tendency was observed for mid-late maturing varieties. In all mature rice types, the late transplanting resulted in a longer pasting time and a higher pasting temperature. In addition, the peak viscosity, breakdown, and gelatinization temperature were significantly lowered, the relative crystallinity degree decreased, and the setback was significantly increased. In the case of Ilpum, a mid-late maturing rice variety, the distribution of amylopectin short chains tended to increase when rice was transplanted on June 30^th.

• Economic and Environmental Geology
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• v.57 no.2
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• pp.263-270
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• 2024

In this study, impact factors for dehydration with KOMIR-Tube system using flocculant and dewatering tube were evaluated for mine drainage sludges. The experiments were conducted on semi-active facility sludges with water contents above 90 % using KOMIR-Tube system. The flocculant and input amount were determined from laboratory experiment and the dewatering efficiency was verified onsite experiment. The sludge characteristics were identified by instrumental analysis such as zeta potential measurement, particle size analysis, XRD, XRF and SEM-EDS. Selection of flocculants for sludge dewatering treatment need to consider not only precipitated rate but also filterated rate. Floc size has to keep at least 0.7 mm. From on-site experiments, sludge dewatering using KOMIR-Tube system suggests to carry out April and May that is low rainfall and humidity considering to climate conditions. Also, dewatering rate depends on the crystal degree of mineral that mainly makes up sludges. Particularly, goethite of the iron hydroxides has better dewatering rate than ferrihydrite. Ferrihydrite is low degree of crystallinity and uncleared or broad shaped crystal, goethite is good crystallinity with needle shaped crystal so that the effect of flocculation and dewatering showed to depend on the crystal. In results, impact factors of dewatering for mine drainage sludges are related to flocculant, climate, crystallinity and shape of iron hydroxides.