• Membrane Journal
• /
• v.17 no.4
• /
• pp.381-386
• /
• 2007

Hollow fibers were made using the nickel slurry containing nickel particles and polymers by phase inversion method. And then, metallic filters were fabricated by sintering method at $1,150^{\circ}C$ under reduction condition. Metallic microfiltration membranes were prepared by coating nickel particles on the metallic filter. The properties of the metallic hollow fiber filters and microfiltration membranes such as pore size and strength were investigated. The metallic membrane showed good resistance against acid, base and chlorine. It was observed that the membrane exhibited good recovery rate by back washing.

• Structural Engineering and Mechanics
• /
• v.60 no.3
• /
• pp.507-527
• /
• 2016

The use of shape memory alloys (SMAs) has been seriously considered in seismic engineering due to their capabilities, such as the ability to tolerate cyclic deformations and dissipate energy. Five 3-D extended end-plate connection models have been created, including one conventional connection and four connections with Nitinol bolts of four different prestress forces. Their cyclic behaviors have been investigated using the finite element method software ANSYS. Subsequently, the moment-rotation responses of the connections have been derived by subjecting them to cyclic loading based on SAC protocol. The results obtained in this research indicate that the conventional connections show residual deformations despite their high ductility and very good energy dissipation; therefore, they cannot be repaired after loading. However, while having good energy dissipation and high ductility, the connections equipped with Nitinol bolts have good recentering capability. Moreover, a connection with the mentioned specifications has been modeled, except that only the external bolts replaced with SMA bolts and assessed for seismic loading. The suggested connection shows high ductility, medium energy dissipation and very good recentering. The main objective of this research is to concentrate the deformations caused by cyclic loading on the connection in order to form super-elastic hinge in the connection by the deformations of the shape memory alloy bolts.

• Journal of Technologic Dentistry
• /
• v.5 no.1
• /
• pp.27-30
• /
• 1983

This study was undertaken to know the difference that margin fittness in metal bond porcelain crown. When we use porcelain precious metal and non-precious metal as porcelain-fused metal, the results were as following. 1. The precious metal was showed best result in margin fittness and shade. 2. The non-precious metals were showed good results, especially Gemini II was excellent, but that was not good than precious metal. 3. 10k. gold plating on non-precious metal cap showed same result as nonprecious metal in margin fittness, and not good in shade. 4. When we use the non-precious metals at upper part of crown, and using precious metal in 2mm cervical portion, the margin fittness were very good, and the results same as full veneer precious metal.

• Journal of the Korean Society of Environmental Restoration Technology
• /
• v.5 no.3
• /
• pp.31-39
• /
• 2002

The main purpose of this study is to select the appropriate wild plants on the rooftop. For the purpose of the experiments, 14 wild plants(12 korean native wild plants and 2 naturalized wild plants) were chosen. As the results of the experiments, the wild plants growing on the culture soil(perlite) Among the 14 kinds of wild plants, such as Chrysanthemum boreale, Taraxacum mongolicum, Aster Koraiensis, Aster yomena, Oenothera odorata, Oenothera lamarckiana, Patrinia scabiosaefolia showed good effects on growth of above ground parts. Therefore, these plants will effective for the rooftop revegation. Callistephus chinensis and Lotus corniculatus var. Japonicus showed good height growth, wherase covering rate was worst. Chrysanthemum boreale, Platycodon grandiflorum, Patrinia scabiosaefolia were plant height, wherase covering rate was not good. As the results of the experiments, the wild plants growing on the culture soil(vermiculite) Taraxacum mongolicum, Aster Koraiensis, Oenothera lamarckiana, Aster yomena showed good effects on growth of above ground parts. Consequently, korean native wild plants such as Taraxacum mongolicum, Aster Koraiensis, Aster yomena and naturalized wild plants such as Oenothera odorata, Oenothera lamarckiana were effective wild plants for rooftop revegetation.

• International Journal of Concrete Structures and Materials
• /
• v.2 no.1
• /
• pp.49-55
• /
• 2008

The disadvantage of PMM's (polymer-modified mortars) that are currently on the market is the utilization of expensive polymer additives and also the cost of the other components. One of the possibilities how to decrease this price is the effective utilization of waste materials which are very inexpensive in spite of their good properties. The combinations of different degree in polymer adhesiveness and waste secondary raw materials - fly ash - are experimentally verified in the paper. The use of fly ash in adhesive materials for ceramic tiles is limited by unsatisfactory initial adhesiveness to sintered ceramic sherd as a result of a running pozzolanic reaction that lowers the efficiency of polymer additives. On the other hand, the use of adhesive and backfill coating materials for gluing ETICS board insulation materials has brought very good results.

• Earthquakes and Structures
• /
• v.11 no.2
• /
• pp.315-326
• /
• 2016

This paper presents the results of cyclic loading tests on concrete beams reinforced with various reinforcement, including ordinary steel bars, CFRP bars and CFRP prestressed concrete prisms(PCP). The main variable in the test program was the level of prestress and the cross section of PCP. The seismic performance indexes including hysteretic loops, skeleton curve, ductility, energy dissipation capacity and stiffness degradation were analyzed. The results show that the CFRP prestressed concrete prisms as flexural reinforcement of concrete beams has good seismic performance. And the ductility and the energy dissipation capacity were good, the hysteresis loops were full and had large area.

• Proceedings of the Polymer Society of Korea Conference
• /
• 2006.10a
• /
• pp.342-342
• /
• 2006

Atomic force microscope (AFM) enables us to stretch a single polymer chain by picking it at its two modified termini. Using this method called "nanofishing," we have studied statistical properties of single polymer chains. A force-extention curve obtained for a polystyrene with thiol termini in a cyclohexane showed a good agreement with a worm-like chain (WLC) model, and thus gave microscopic information about entropic elasticity. In this report, the experiments were performed at wide-range temperatures, resulting in wide-range solvent qualities from poor to good solvent condition. The temperature dependence of statistical properties of polystyrene was examined. The coil-strand transformation realized in a poor solvent was also discussed.

• Proceedings of the KIEE Conference
• /
• 2001.07c
• /
• pp.1881-1883
• /
• 2001

We manufactured a micro CPL by LlGA process, a new conceptual ultra-fine and precise forming method, using X-ray lithography process. We fabricated a BN X-ray mask having properties of good X-ray transmittance and large mechanical strength. Micro CPL was manufactured by dividing into an upper plate and a low plate. Each of plates was bonded by Ag paste screen printing. The upper plate was fabricated on glass wafer to observe flow and phase transformation of cooling solution. The lower plate was manufactured by Cu electroplating for good heat transmission. Precision of inner Parts, micro pin and micro channel, of manufactured micro CPL is under ${\pm}2{\mu}m$.

• Journal of the Korean Applied Science and Technology
• /
• v.25 no.4
• /
• pp.411-417
• /
• 2008

A group of new N,N-bis(5-acetylpyridin-2-yl)phenylamine derivatives was synthesized in good yield applying an optimized Buchwald-Hartwig amination protocol. The synthesized compounds showed UV absorption maxima in the range of 320-360 nm, and showed good luminescence at dilute concentrations in the blue region of the spectra (in the range of 480-497 nm). They showed also a bathochromic shift associating the increase in solvent polarity. The synthesized compounds could be investigated for use in OLEDs or as potential monomers for PLEDs.

• Proceedings of the Korean Society for Technology of Plasticity Conference
• /
• 2002.02a
• /
• pp.144-147
• /
• 2002

In this study, springback analysis of side rear member is carried out. Side rear member is one of the parts which shows severe springback problems. Forming, trimming, flanging and springback stages can be analyzed successively. From forming analysis, we identified the possible spots in which tearing may occur and can prevent failure. In springback analysis we used the boundary conditions same as applied to the blank on the checker so that the computational result can be compared with experimental one. Form .the comparison, springback analysis can yield relatively good results in a qualitative sense. However, in order to get good deformation result quantitatively, there still remains unsettled tasks in the forming analysis with very small die radius. It is found that we have to develop the element with better bending characteristics and precise contact treatment.