• Korean Journal of Environment and Ecology
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• v.24 no.4
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• pp.406-425
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• 2010

The flora for resource plants in Hapcheon-gun were investigated 10 times from March to October, 2009. Based on collected voucher specimens, the flora of this area consisted of 489 taxa in total; 82 families, 292 genera, 427 species, 4 subspecies, 49 varieties and 9 forms. The resources plants in the area were categorized by usage into 9 groups including an unknown group: 187 edible, 126 pasturing, 137 medicinal, 112 dyeing, 52 ornamental, 16 timber, 9 fiber, 2 industrial taxa and 134 unknown resource plants were recorded respectively. In addition, there were 18 taxa of Korean endemic plants, 33 taxa of specific plants which were designated by the Ministry of Environment, and 2 taxa of rare plants. Furthermore, 44 taxa of naturalized plants were observed in this investigated area. The vegetation status of the investigated area was well conserved, but it is likely that the contaminated area could be rapidly increased and exacerbated by the climbers and development of forest roads. Therefore, the systems for conservation need to be prepared for the effective management of forests, and there must be special rules to control the number of climbers and visitors.

• Journal of the Korea Society of Computer and Information
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• v.17 no.8
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• pp.107-114
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• 2012

We have developed a textile capacitive pressure sensor for smart gait analysis. The proposed system can convert sensor signal into step counts and pressure levels by different posture. To evaluate the performance of insole type textile capacitive sensor, we measured capacitance change by increment of weights from 10 kg to 100 kg with 10 kg increment using M1 class rectangular weights (four 20 kg weights and two 10 kg weights) which have ${\pm}10%$ tolerance. The result showed non-linearity characteristic of a general capacitive pressure sensor. The test was performed according to a test protocol for four different postures (sitting, standing, standing on a left leg and standing on a right leg) and different walking speeds (1 km/h and 4 km/h). Five healthy male subjects were participated in each test. As we expected, the pressure level was changed by pressure distribution according to posture. Also, developed textile pressure sensor showed higher recognition rate (average 98.06 %) than commercial pedometer at all walking speed. Therefore, the proposed step counts and posture monitoring system using conductive textile capacitive pressure sensor proved to be a reliable and useful tool for monitoring gait parameters.

• Polymer(Korea)
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• v.34 no.3
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• pp.282-288
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• 2010

The porcine small intestinal submucosa (SIS) has been widely used as a biomaterial without immuno rejection responses and hyalunonic acid (HA) can be used as biocompatible materials to regenerate tissue. We developed the SIS sponge and HA loaded SIS sponges (SIS/HA) for the possibility of the application of the tissue engineering using annulus fibrosus (AF). SEM observation shows that SIS and SIS/HA sponges have interconnected and open pores. We demonstrated the presence of HA in SIS/HA sponge from C-O functional group observed by the FTIR analysis. In conclusion, we suggest that SIS/HA sponge may be useful to tissue engineering using AF cell. This may be due to the enhanced biocompatibility and higher water retention capacity of HA.

• Polymer(Korea)
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• v.27 no.2
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• pp.106-112
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• 2003

Poly(trimethylene terephthalate)(PTT) fibers were treated by passing on the plate heater to study the annealing effect on the change of morphological structure and physical properties. In the X-ray diffraction curves of PTT annealed, a sharp peak at 2$\theta$=15.6$^{\circ}$ appeared and the peak intensity became stronger with the increase of annealing temperature and time. This peak was based on the (010) plane of PTT crystals. The crystallinity determined by density measurement was also increased by annealing. With the increases of temperature and time, the dynamic viscoelastic behaviors were shown to be a large reduction in T(tan $\delta$$_{max}$). The birefringence and $T_g$ were also reduced, but the melting temperature was the same. These results mean that the molecular chains in armorphous region are transfered into the crystalline legion, making the remained chains relaxed during annealing at tensionless state.

• Journal of the Korean Ceramic Society
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• v.38 no.10
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• pp.928-935
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• 2001

In this study, two kinds of activated carbon fibers were prepared from PAN-based stabilized fibers by physical activation with steam. The variations in specific surface area, amount of iodine adsorption and pore size distribution of the activated carbon fibers after the activation process were discussed. The activated carbon fibers were prepared by two different methods, namely a 1- and 2-step method. For the 2-step method, carbonization of fibers in $N_2$ atmosphere was carried out to make carbon fibers and then activated by steam. In normal two step steam activation, BET surface area of about $1019m^2/g$ was obtained in the study. In the 1-step steam activation process, the carbonization and activation were simultaneously carried out. In the one step steam activation, BET surface area of $1635m^2/g$ was obtained after heat-treatment at $990^{\circ}C$. However, nitrogen adsorption isotherms for oxidized PAN based activated carbon fibers that were prepared by both methods were type I in the Brunauer-Deming-Deming-Teller (BDDT) classification even though they have different BET surface areas, amounts of iodine adsorption and pore size distributions.

• Food Science of Animal Resources
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• v.33 no.1
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• pp.119-124
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• 2013

This study was conducted to investigate meat quality and sensory characteristics between castrated and non-castrated dairy goats. Dairy goat of Saanen breeds was slaughtered at an age of 6 mon. Then, characteristics of dairy goat meat were analyzed to chemical compositions, collagen content, pH, meat color, cooking loss, water-holding capacity, shear force, protein solubility, and myofibrillar protein fractions by sodium dodecyl sulfate polyacrylamide gel electrophoresis (SDS-PAGE). Also, odor from dairy goat meats was analyzed by sensory evaluation and volatile substances by gas chromatography-mass spectrometry (GC-MS). As a result, the chemical compositions and physicochemical characteristics were not significantly different between castrated and non-castrated dairy goats meat. Also, there is no difference protein solubility (sarcoplasmic, myofibrillar and total protein) and protein fraction by SDS-PAGE. Sensory evaluation results in odour scores are highly (p<0.05) non-castration dairy goat meat better than castration. As a result, overall palatability was higher (p<0.05) in castrated goat meat when compared with non-castrated one. The indole and octadecanoic acid by GC-MS based on sensory evaluation results were only detected in non-castrated dairy goat meat. Therefore, distribution for goat meats castrated compared to non-castrated dairy goat meat is expected to be able to get a good response to the Korean consumer.

• Journal of the Korean Recycled Construction Resources Institute
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• v.2 no.1
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• pp.120-127
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• 2006

The hammer-milled characteristics of waste wood materials such as lumber, plywood, particleboard(PB), MDF and railroad tic were investigated in this study. The physical and mechanical properties of recycled boards according to types of recycled particle and the mixing ratios were also studied. The hammer-milled, waste wood materials had the dimensional distributions suitable for the core layer panicle. Bending strengths of recycled boards (one layer) were shown in order of plywood, PB(laboratory-fabricated with particles used in the PB factory), lumber, tego film-overlaid plywood, MDF, waste railroad tie, PB(factory-made) and LPL-overlaid PB. Cured resin and creosote containing waste wood contributed to dimensional stability of reconstituted boards. Considering the mixing effects between lumber and plywood with recycled PB particle, lumber particle was contributive to bending strength, MOE and internal bond(IB) strength, whereas plywood particle was contributive to dimensional stability. The bending and IB strength of 3 layer boards composing only recycled waste wood particles in core layer of board were in order of lumber, plywood, PB and MDF. On the other hand, the thickness swelling was in order of PB, lumber, plywood and MDF. Bending strength of the 3 layer boards mixed with recycled PB-particle in the core layer had a decreasing tendency, as the mixing ratios of recycled PB-particles increased. The dimensional stability of 3 layer recycled board was improved as the mixing ratio of recycled PB-particle increased same as in one layer. Formaldehyde emission of boards fabricated with recycled PB-particles in the core layer of the PB was in the range of E2 grade (below 5.0mg/l).

• Journal of Korean Society of Forest Science
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• v.60 no.1
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• pp.45-50
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• 1983

According to the worldwide decreasing tendency in raw materials and increase in wood demands since 1970, the efficient utilization of raw materials was required internationally. Therefore this study dealt with the dimensional characteristics of branchwood fiber of Quercus serrata Thunb for the complete utilization of whole tree. According to the branch individuals, parts and positions within a tree, fiber length, width and wall-thickness were measured. The results obtained are as follows: 1) As the height of individual branchwood increases from ground toward, fiber length and width, and wall-thickness decreased linearly and their regression equations obtained, were Y=770.03-22.643X, Y=27.444-0.71385X and Y=12.308-0.57320X respectively 2) From the main stem to branch in distal direction, fiber length, width and wall-thickness linearly decreased and their regression equations obtained were Y=752.70-0.6724X, Y=26.152-0.0084867X and Y=11.258-0.006205X, respectively. 3) As the radial direction from pith to hark increases, fiber length, width and wall-thickness increased linearly and their regression equations obtained were Y=679.73+11.231X Y=25.382+0.0925X and Y=10.521+0.11787X, respectively. 4) Mean value of fiber length, width and wall-thickness were 625-765, 26 and $11{\mu}m$, respectively.

• Korean Journal of Food Science and Technology
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• v.28 no.1
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• pp.169-178
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• 1996

Target parameters such as water solubility index (WSI), intrinsic viscosity (IV), water holding capacity (WHC), oil holding capacity (OHC), soluble dietary fiber (SDF) and microstructure were investigated on three different screw configurations during twin-screw extrusion of wheat bran. WSI of raw wheat bran (RWB) was 13.7%, while that of extrudates ranged $16.3{\sim}23.2%$ when extruded using screw configurations with 5 reverse screw elements (RSE). It was found that the moisture content of RWB greatly affected WSI of extrudates. IV of wheat bran extrudates increased from 10.6 ml/g of RWB to $37.86{\sim}44.37\;ml/g$ of extrudates extruded using 3, 4 and 5 RSE, whose trend was highly related to the moisture content of RWB and the extrusion pressure. Multiplication of IV and soluble solid (SS) content exhibited good correlation $(R^2=0.85)$ with specific mechanical energy (SME). The results suggested that SS and molecular size are an important factor governed by the SME in solubilization of wheat bran. WHC increased with increasing feed rate and moisture content, while OHC decreased. SDF increased from 2.68% of RWB to $4.32{\sim}6.48%$ of extruded wheat bran, indicating the significant breakdown of cell wall components. Microstructure of the extrudates showed the distinct patterns of degradation and solubilization of cell wall structure, depending on the moisture content of RWB.

• Journal of Aerospace System Engineering
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• v.13 no.6
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• pp.52-59
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• 2019

The rotor blade is a key component that generates the lift, thrust, and control forces required for helicopter flight by the torque transmitted through the hub and the blade pitch angle control, and should be designed to factor vibration characteristics so that there is no risk of resonance with structural safety. In this study, the structural design of the main rotor blade for MPUH(Multi-Purpose Unmanned Helicopter) was conducted and the sectional stiffness measurement of the fabricated blade was performed. The evaluation of the vibration characteristics of the main rotor system was then conducted factoring the measured stiffness distribution. The interior of the rotor blade comprised of the skin, spar, and torsion box, and carbon and glass fiber composites were applied. The Ksec2D program was applied to predict the stiffness of blade, and the results were compared to the measured data. CAMRADII, a comprehensive rotorcraft analysis program, was applied to investigate the natural frequency trends and resonance risks due to the rotor rotation.