• Membrane Journal
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• v.16 no.2
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• pp.159-166
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• 2006

MFI(Mobil Five) structured hydrophobic ZSM-5 zeolite membrane was used for selective pervaporation of trichlorinated organic compounds(trichloromethane, trichloroethane, trichloroethylene) from their aqueous solutions. ZSM-5 zeolite membrane was hydrothermally synthesized on the inside of a porous stainless steel tube by secondary growth employing ZSM-5 seed powders. Separation factors for each binary mixtures were observed $16{\sim}66$ for trichloromethane/water, $3.3{\sim}4.6$ for trichloroethane/water and $1.4{\sim}8$ for trichloroethylene/water at the experimental conditions of the feed mole fraction from 0.0001 to 0.001 with temperature ranged $25{\sim}35^{\circ}C$.

• Journal of the Korean Society of Radiology
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• v.6 no.6
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• pp.477-481
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• 2012

An X-ray diffractometer which has various X-ray optics can give qualitative and quantitative information for a sample using a nondestructive analysis method. A parallel beam optic passes the parallel beam and removes divergent beam generated from an X-ray tube. The parallel beam optic used in the X-ray diffractometer was fabricated by wire cut and grading of stainless steel plates and was evaluated its performance using an X-ray imaging system. The measured parallelization of 6.6 mrad for the fabricated the parallel beam optic was a very close to the expected value of 6 mrad. An X-ray imaging technique for evaluating the parallel beam optics can estimate parallelization for each plate and can be used to other X-ray optics.

• Journal of Korea Foundry Society
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• v.29 no.5
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• pp.220-224
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• 2009

In order to investigate the microstructural morphology of the sulfide expected from the Fe-FeS phase diagram, a vacuum-sealed quartz tube where pure iron (99.9%) and sulfur (99.99%) powders were charged was heated upto $1000^{\circ}C$ in the electric resistance furnace, held for 96 hours and quenched in cold water and then, rod specimen was produced. Compositional difference of the sulfur between upper and lower parts of the rod was 7.5wt.% and segregation of the sulfur was gradually increased from the lower part to the upper one of the rod. The rod specimen was divided into three parts by the microstructural morphology of the sulfide. The upper part of the rod specimen revealed single phase FeS intermetallic. In the middle part of the specimen, hyper-eutectic microstructure where primary FeS was precipitated first and then, eutectic of $\alpha$-Fe and FeS was formed in the inter-dendritic region of the FeS. Especially, hypo-eutectic microstructure was appeared in the lower part of the specimen. After primary dendrite of $\alpha$-Fe solidified, FeS dendrite which included small amount of $\alpha$-Fe and FeS eutectic in the inter-dendritic region was formed.

• Journal of the Korean Geotechnical Society
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• v.28 no.11
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• pp.53-67
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• 2012

In this research, stainless steel and heat-shrinkage tube were used for new TDR sensing line to solve the problems of ordinary TDR system. The new TDR line improved the sensitivity of water content and endurance, and reduced the data noise. The saturation degree test and acryl model test were done by revised TDR sensor. From the results, without additional data filtering and quantitative analysis, the raw data were separated into 3 zones; saturated, unsaturated and dried zones easily. In addition, the revised TDR sensor was installed in large-scale embankment model to perform the seepage test. The raw data of the model tests showed the distributed seepage behaviors and separated zones clearly, which were almost the same tendencies as the lab test results.

• International Journal of High-Rise Buildings
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• v.7 no.1
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• pp.17-32
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• 2018

This paper explores the function of a structural skin with an embossed surface applicable to use for tall building structures. The major diagrid system with a secondary embossed surface structure provides an enhanced perimeter structural system by increasing tube section areas and reduces aerodynamic loads by disorienting major organized structure of winds. A parametric study used to investigate an optimized configuration of the embossed structure revealed that the embossed structure has a structural advantage in stiffening the structure, reducing lateral drift to 90% compared to a non-embossed diagrid baseline model, and results of wind load analysis using computational fluid dynamics, demonstrated the proposed embossed system can reduce. The resulting undulating embossed skin geometry presents both opportunities for incorporating versatile interior environments as well as unique challenges for daylighting and thermal control of the envelope. Solar and thermal control requires multiple daylighting solutions to address each local façade surface condition in order to reduce energy loads and meet occupant comfort standards. These findings illustrate that although more complex in geometry, architects and engineers can produce tall buildings that have less impact on our environment by utilizing structural forms that reduce structural steel needed for stiffening, thus reducing embodied $CO^2$, while positively affecting indoor quality and energy performance, all possible while creating a unique urban iconography derived from the performance of building skin.

• Proceedings of the Korea Institute of Applied Superconductivity and Cryogenics Conference
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• 2003.10a
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• pp.301-303
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• 2003

The KSTAR(Korea Superconducting Tokamak Advanced Research) superconducting magnet system consist of 16 TF(Toroidal Field) and 14 PF(Poloidal Field) coils. Internally-cooled cabled superconductors will be used for the magnet system. The magnet system adopt a superconducting CICC (Cable-In-Conduit Conductor) type. The KSTAR PF 6, 7 CICCs use NbTi Superconducting cable with stainless steel 316LN conduit while the other PF CICC use Incoloy 908 conduit. For the fabrication of PF CICC, superconducting cables have been fabricated and the cable has the diameter of 22.3mm. A continuous CICC jacketing system is developed for the CICC jacketing and the jacketing system uses the tube-mill process, which consists of forming, welding, sizing and squaring procedures. The cabling and the jacketing process is described. The welding condition and design specification of CICCs are also discussed. The fabrication results including the geometrical specification and the void fraction will be discussed.

• Journal of the Computational Structural Engineering Institute of Korea
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• v.21 no.3
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• pp.287-294
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• 2008

This study proposes a novel method for in service evaluation of tension force of a prestressed 7-wire strand which is frequently employed for retrofitting bridge superstructure. The smart strand is made by replacing the straight king wire of the strand with an instrumented steel tube in which the FBG sensor is embedded. Since the strain of the smart strand can easily be measured using the sensor, it is possible to monitor tension force of the strand during the service. For the sake of demonstrating effectiveness of the proposed strand, we came up with a 7.0m long prototype with 2 FBG sensors, and it is applied as an external tendon to a 6.4m long and 0.6 high RC T-shaped beam. A loading-unloading test has been carried out, and estimated tension forces using the smart strand are compared with measured forces by load cell. The comparison showed that the proposed smart tendon is useful and accurate for monitering tension force of the prestressed tendon.

• Corrosion Science and Technology
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• v.9 no.6
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• pp.331-337
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• 2010

This study compared the macro and micro electrochemical characteristics at the local area of welding metal on dissimilar welding parts for type 304 stainless steel (SS) and type 316L SS. The materials are used for double wall gas pipe of duel fuel engine for a ship. The various potentiodynamic experiments were performed several times in 10% ${H_2C_2O_2}{\cdot}{H_2O}$ solution using macro and micro methods, respectively. The micro electrochemical experiments conducted to resolve at local area on cross-section of dissimilar welding materials by micro-droplet cell device. The micro-droplet cell techniques can be used almost electrochemical experiments to resolve corrosion characteristics of the limited electrode area of the metallic surface between wetted spot of working electrode and tip of sharpened capillary tube. The results of macro electrochemical experiments show that resistance of active dissolution reaction at welding zone was high due to low current density by formation of passivation protection film at passive region. According to the micro electrochemical experiment, the corrosion current density of welding zone and bond zone were relatively high.

• Journal of the Korean GEO-environmental Society
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• v.9 no.2
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• pp.61-65
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• 2008

In this study, a newly modified soil nailing technology named as the PGSN (Pressurized Grouting Soil Nailing) system is proposed. Effects of various factors related to the design of the pressurized grouting soil nailing system, such as the length of re-bars and type of reinforcement materials, were examined throughout a series of the displacement-controlled field pull-out tests. 9 displacement-controlled field pull-out tests were performed and the ratio of injected grout volume to grout hole volume were also evaluated based on the measurements. In addition, short-term characteristics of pull-out deformations of the newly proposed PGSN system were analyzed and compared with those of the ordinary soil nailing system by carrying out field pull-out tests. The test results were shown that the displacements of pressurized grouting soil nailing system were decreased 30~36% in comparison with using gravity grouting soil nailing system by the pressurized effect. The displacements of steel tube were diminished 31~32% comparison with using deformed bar by the reinforcement type change from the field pull-out tests.

• Journal of the Korean Ceramic Society
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• v.44 no.7
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• pp.362-367
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• 2007

Stent is a tiny structure made with either ceramic coating and/or bare metal. Being approximately $1{\sim}2 mm$ in diameter, it consists of holes, slots, or void space and is designed to cover entire medical lesions. Stent implantation into patients' arteries has been practiced for a little more than a decade in order to widen the blocked artery. The adoption of the stent has significantly improved the efficacy when compared with the previous medical practice by balloon angioplasty alone. Yet better biomedical performance of the stent is being demanded in order to eliminate the still existing problem of artery restenosis, which means the artery becomes narrowed again. Recent literature survey shows researches on ceramic coatings onto the stent surface, or material design to improve the mechanical response of the stent. This study focuses more on the material design and mechanical analysis. The results showed that the void configuration within the stent affects the mechanical response significantly. The rectangular shape was found to yield expansion at a relatively lower pressure than the elliptical slot for a slotted tube stent. The present results, when combined with research on coating at the stent surface, may provide stents with improved bio-medical performance.