• Journal of the Korean Crystal Growth and Crystal Technology
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• v.32 no.5
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• pp.199-204
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• 2022

A new three-dimensional Gd-MOF, [Gd(p-XBP4)₄(H₂O)]·W(CN)₈; (1; p-XBP4 = N,N'-p-phenylenedimethylenbis (pyridin-4-one)) has been synthesized by slow-evaporation and its crystal structure was characterized by single-crystal X-ray diffraction (SCXRD) analysis. For each Gd^III ion, there are seven coordination sites, which are occupied by six oxygen atoms of six p-XBP4 ligands and one oxygen atom from the water molecule. The [W(CN)₈]^3- anion exists for charge balance with cationic framework. The Gd^II ions are interconnected by the p-XBP4 ligand to form the three-dimensional structure. Considering the magnetic property of lanthanide ions, magnetic studies of Gd-MOF were investigated by direct-current (DC) magnetic susceptibilities measurements.

• Textile Coloration and Finishing
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• v.34 no.3
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• pp.135-145
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• 2022

In this study, the dyeability of 0.06-denier-per-filament (dpf) ultrafine sea-island-type nylon knitted fabric was investigated and compared with that of 1.0-dpf general nylon with respect to four types of dyes. In particular, leveling, milling, half-milling, and metal-complex dyes were compared at concentrations of 0.5%, 1.0%, 2.0%, 4.0%, and 8.0% on-weight-fabric (o.w.f). In each case, staining was performed at 100 ℃. The dyeabilities of the materials were compared in terms of the depth of color as defined by the ratio of the absorption coefficient (K) to the scattering coefficient (S). Results indicated generally low K/S values for both the 0.06-dpf ultrafine sea-island-type nylon and 1.0-dpf general nylon. In terms of the dye type, the milling and half-milling dyes exhibited K/S values of ≥20 for all colors of yellow, red, and blue for the 0.06-dpf ultrafine yarn sea-island-type nylon, which were superior to those of the other dye types. Hence, the milling and half-milling dyes are considered more suitable than the other dyes. Further, a comparison of dye fastness and compatibility revealed that the half-milling dye was the most suitable dye for the 0.06-dpf ultrafine sea-island-type nylon.

• Journal of the Korean Wood Science and Technology
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• v.32 no.5
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• pp.45-50
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• 2004

Currently, structural design of wood structure has been based on ASD (Allowable Structural Design) in Korea. However, the results from this method was known as greater than real value because variations of materials and various conditions were not considered sufficiently. So the study about the design method with probabilistic approach is being performed to overcome this problem. And the standard design method of RBD (Reliability Based Design) has been established and applied. In this study, to apply this method on the domestic wood, the distribution property of the lumber and Glulam was analyzed from the previous report and the basis of the standardized design method was established as soft conversion method from allowable stress used in ASD into reference resistance used in RBD. And through the additional study about the sample size as a important factor to effect on soft conversion, condition to be required in more accurate conversion was evaluated.

• Journal of Software Assessment and Valuation
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• v.16 no.2
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• pp.25-35
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• 2020

In the Korean litigation system, structural maldistribution of evidence still remains a conundrum. Numerous solutions have been discussed so far and, today, few people deny the need for adopting a system similar to the discovery procedure in the United States. In the intellectual property (IP) domain, a wide range of legislative attempts have been made to improve the litigation system, especially for patent litigation. However, the adoption of discovery in copyright litigation is seldom discussed, despite the fact that copyright infringement lawsuits increasingly involve highly technical issues, especially in case of copyrightable computer programs. The lack of discussion on discovery adoption forms a stark contrast with the active attempts to adapt and adopt discovery procedure for patent litigation. In copyright infringement lawsuits, especially for copyrighted computer programs, securing evidence takes on crucial importance. However, in reality, there are numerous obstacles. Some lawsuits proceed even without properly securing the infringed work. To address this issue, the current litigation system needs to be improved by adopting a procedure similar to discovery. This paper reviews what solutions are being utilized today, and how we should approach the issue.

• Structural Engineering and Mechanics
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• v.82 no.3
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• pp.295-312
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• 2022

This study investigates the effects of nano silica (NS) and micro steel fiber on the properties of ultra-high-performance concrete (UHPC). The experimental consists of three groups, each one with five percentages of NS content (0%, 2%, 4%, 6% and 8%) in addition to the 20% silica fume and 20% quartz powder proportioned according to the weight of cement added to the mixtures. In addition, three percentages of micro steel fibers (0%, 1% and 2%) were considered. Different mixtures with varying percentages of NS and micro steel fibers were prepared to set the water-to-binder ratio, such as 0.16% and 1.8% superplasticizer proportioned according the weight of the binder materials. The fresh properties, mechanical properties and elevated temperatures of the mixtures were calculated. Then, the results from the microstructure analyses were compared with that of the reference mixtureand it was found that 6% replacement of cement with NS was optimum replacement level. When the NS content was increased from 0% to 6%, the air content and permeability of the mixture decreased by 35% and 39%, the compressive and tensile strength improved by 21% and 18% and the flexural strength and modulus of elasticity increased by 20% and 11.5%, respectively. However, the effect of micro steel fibres on the compressive strength was inconclusive. The overall results indicate that micro steel fibres have the potential to improve the tensile strength, flexure strength and modulus of elasticity of the UHPC. The use of 6% NS together with 1% micro-steel fiber increased the concrete strength and reduce the cost of concrete mix.

• Composites Research
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• v.36 no.1
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• pp.32-36
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• 2023

Recently, as global environmental issues for sustainable development, such as carbon neutrality, have emerged, disposal methods of glass fiber composites, a material of existing wind turbines, have become a problem. To solve this problem, in this study, 30kW wind turbine blades were manufactured using flax fiber-based composites, which are eco-friendly natural fiber composites that can replace existing glass fiber composites, and their suitability was evaluated. First, mechanical strength tests were conducted to verify the feasibility of using eco-friendly natural flax fiber composites as a wind turbine blade material, and as a result, better strength were confirmed compared to previous studies on the properties of flax fiber composites. In addition, the suitability was confirmed through a static strength performance evaluation test to measure the static strength of the flax fiber composite blade using the manufactured 30kW class flax fiber composite blade.

• The Journal of Advanced Prosthodontics
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• v.15 no.4
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• pp.189-201
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• 2023

PURPOSE. The aim of this study was to investigate the mechanical properties of three-dimensional (3D) printed denture base resin incorporating microcapsules containing plant essential oils. MATERIALS AND METHODS. Denture base specimens containing up to 3% w/v essential oil microcapsule powders (MCPs), i.e., eucalyptus, geranium, lavender, menthol, and tea tree, in two resins (Detax and NextDent 3D+) were 3D printed using two printers (Asiga and NextDent 5100). The dispersion and interaction of the MCPs in the resin were assessed by SEM while the mechanical properties of the incorporated denture base including flexural strength (MPa), flexural modulus (MPa), Vickers hardness (VHN), and surface roughness (Ra) were also subsequently evaluated. Statistical analysis of any differences in mean values was determined using a two-way ANOVA with Tukey's post hoc testing (α = .05). RESULTS. The spherical shape of the MCPs was maintained during the mixing and polymerization/printing process. However, the Detax-Asiga group showed significant agglomeration of the MCPs even at the lowest MCP concentration levels (0.5% w/v). Overall, as the microcapsule concentration increased, the mean flexural strength decreased, though the menthol MCP groups remained compliant with the ISO standard. The flexural modulus and harness remained relatively unchanged, and the flexural modulus complied with the ISO standard regardless of the MCP concentration. Surface roughness increased with the addition of the MCPs but also remained below that required for clinical acceptance. CONCLUSION. Incorporation of microencapsulated plant essential oils into 3D printed denture base resin was successfully achieved. While incorporation negatively influenced flexural strength and surface roughness, little effect on flexural modulus and Vickers hardness was demonstrated.

• Journal of Practical Agriculture & Fisheries Research
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• v.10 no.1
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• pp.169-181
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• 2008

The purpose of this study was to produce Pleurotus ostreatus using fermenter with bag cultivation. These results are as follows. 1. While mushroom composts were being fermented in a fermenter, the physical property of the fermented composts was getting better when there isn't any screw or revolving flies in the fermenter and the strength of pressing the composts was getting less. 2. The composts were fermented well as slaked lime of 1% density added to the composts. 3. According to the result of examining our fermenting ways, composts were in the best condition after being fermented for 48 hours since the temperature in a fermenter has come to 60℃, which could be reached by heating the fermenter by 40℃ after putting compost materials and water into it. 4. The good condition of fermenting could be maintained by controlling the speed of revolving flies, therefore the speed be down when the temperature is above 60℃ and up bellow 60℃. 5. Since the composts had been added with 1.5~2% of cottonseed meal or rice bran, the fermented composts were in good condition and also the quantity and quality of the mushroom produced on the fermented composts were satisfied. 6. There were needed 7 hours of labour for 3days from the first day of putting composts into a fermenter for fermenting 3.5M/T(10,000~12,000bags of 750~800g per bag) of composts to the third day of finishing the fermenting work, and also the cost was 112,066￦(130$) including 52,066￦(60$) of electric charge and fuel expense.

• Clean Technology
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• v.15 no.3
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• pp.180-185
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• 2009

The ethylene-propylene rubber (EPDM) scrap generated from automobile weatherstrip manufacturing process was used to make a thermoplastic elastomer through blending with polypropylene. The surface activated EPDM powder was obtained by the high temperature and shear pulverizer. The addition of surfactant resulted in more surface activated EPDM powder and the optimum loading amounts of surfactant was 1.5 phr. Maleic anhydride was grafted onto polypropylene by reactive blending to give functionalized polypropylene. The wetting property between EPDM scrap and polypropylene was improved by the addition of poly (ethylene-co-acrylic acid) as a compatibilizing agent. Poly(ethylene-co-acrylic acid) decreased the surface tension of polypropylene and thus would contribute to the wettability with EPDM powder.

• Journal of the Korean Geosynthetics Society
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• v.22 no.1
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• pp.1-7
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• 2023

This study has utilized self-assembled monolayers technology to improve electrical property of graphene-oxide, which has been seperated graphine powder through a chemical exfoliation. Aluminum sulfate (Al₂(SO₄)₃) was applied on graphene-oxide as a reactant, and the fundamental research was carried out to apply on the self-sensing of cement-based construction structures. Electric resistance measurement result has shown that cement-composites with GO and Al-GO can be used as a conductor, electric resistance of GO and Al-GO contained composites improved by 10.2% and 15.9% respectively when compared to the standard cement-composite. Microstructure analyzation shown the formation of Al(OH)₃ gel when Al-GO was added, which is speculated to result the smooth flow of current by improving the density of cement-composite. This implies that graphene-oxide has a possibility to be utilized as smart building materials and construction structure itself rather than just a structure.