• The Transactions of the Korean Institute of Electrical Engineers B
• /
• v.50 no.4
• /
• pp.164-169
• /
• 2001

This paper deals with comparison of characteristics of continuous-sheet type low-Tc superconducting (LTS) power supply and discrete-sheet type LTS power supply. These characteristics have been analyzed through experiments. These power supplies consist of two exciters, a rotor, a stator, and a LTS load. A continuous-sheet type has a single continuous niobium (Nb) sheet attached to the inner surface of on the stator. In the case of discrete-sheet type, four separated Nb sheets are used. this experiment is using 1.81 mH LTS magnet load and maximum 30 A dc exciter current. A discrete-sheet type is expected to produce much better pumping rate than a continuous-sheet type. The experimental observations have been compared with the theoretical predictions. In this experiment, the maximum pumping-current has reached about 926 A.

• Journal of the Korea Academia-Industrial cooperation Society
• /
• v.8 no.1
• /
• pp.103-109
• /
• 2007

A new steel sheet pile of wide hat-type was developed. Advantage of using wide type of sheet pile is reducing steel weight and consequently cutting down construction cost. Field driveability tests were conducted in order to verifying vibro-driveability of wide hat-type sheet pile. As a result of the tests, penetration rates of newly developed sheet piles were less than those of U-type sheet piles. Axial stresses developed in sheet pile during driving were fur less than yield stress of sheet pile. Futhermore, initial penetration rates of sheet piles were much larger than those obtained from WEAP program.

• Journal of Digital Convergence
• /
• v.12 no.8
• /
• pp.303-308
• /
• 2014

In this paper, a ferrite sheet at the back of the smartphone by type, pattern, stars, the thickness of the recognition distance by attaching the NFC optimum ferrite sheet simulation was designed. Characterized by patterns rather than the Full-type I-type communication distance of about 1 ~ 2mm more extended. Ferrite sheet metal by applying the NFC antenna is effective in improving the characteristics were confirmed. In the case of the pattern C, the permeability is 140, a thickness of 0.1mm, Full-type ferrite sheet when applied to NFC communication distance than normal electromagnetic absorber is increased from 45 to 59 was confirmed that.

• Proceedings of the Korean Geotechical Society Conference
• /
• 2000.03b
• /
• pp.325-330
• /
• 2000

In general steel sheet pile use the containment system, vertical barrier systems for waste disposal and landfill purposes, roads in excavation which have a more permanent character or temporary structure. The sheet pile joints between section of the wall are sealed with a filter material arid the resistance to seepage is a function of the type of material employed. The aim of this paper is to review a characteristic of permeability for Z type sheet pile by field test in various condition.

• Bulletin of the Korean Mathematical Society
• /
• v.55 no.1
• /
• pp.9-23
• /
• 2018

In this paper, inspired by the fractional Brownian sheet of Riemann-Liouville type, we introduce the operator fractional Brownian sheet of Riemman-Liouville type, and study some properties of it. We also present an approximation in law to it based on the martingale differences.

• Journal of the Korean Society for Precision Engineering
• /
• v.16 no.7
• /
• pp.210-218
• /
• 1999

Sheet deposition type rapid prototyping system have many advantages : high build speed, low operating cost, large part size, no phase change, no need for support generation, and forth. However, those sheet deposition type rapid prototyping system require an additional post processing to remove excessive material attached to the part. This post processing is time consuming and labor intensive. Moreover, it is difficult for those system to fabricate parts with hollow cores and internal cavities. A new sheet deposition type rapid prototyping system that minimizes the post processing is proposed. The proposed system automatically removes excessive material in a peeling-off process between two cutting processes. In this way, the proposed system can reduce the post-processing time and cost as well as the limitation of the feasible geometric shapes in the conventional sheet deposition system.

• 한국금형공학회:학술대회논문집
• /
• 2008.06a
• /
• pp.31-34
• /
• 2008

The L-bending of inner-structure bonded sandwich sheet metal is examined to reduce springback and defects of bent parts. The specimen is composed of top and bottom layers and a middle layer with dimple type-inner-structure and each layer is bonded by resistance welding. This specimen with hollow type-inner-structure shows different bending characteristics from the conventional sandwich sheet metals with solid type-inner-structure. The experiments were conducted for two kinds of working conditions, that is, clearance and movement of first bent specimen for second bending. The deformed profile, bend angle and springback were investigated and compared and then the proper working conditions for L-bending of sandwich sheet metal were prosed.

• Journal of ILASS-Korea
• /
• v.10 no.4
• /
• pp.32-46
• /
• 2005

The breakup characteristics of liquid sheets formed by the impinging and swirl type injectors were studied as increasing the Weber number (or injection condition) and the ambient gas pressure to 4.0.MPa. In the case of impinging type injector. we compared the changes of breakup lengths between laminar and turbulent sheets. which are formed by the impingement of laminar and turbulent jets. respectively. The results showed that both sheets expand as increasing the injection velocity irrespective of the ambient gas density when the gas based Weber number is low. When the Weber number is high, however, the breakup of turbulent sheet depends on the hydraulic force of jets as well as the aerodynamic force of ambient gas which determines the breakup of laminar sheet. Using the experimental results. we could suggest empirical models on the breakup lengths of laminar and turbulent sheets. In the case of swirl type injector. as $We_l$, and ambient gas density increased, the disturbances on the annular liquid sheet surface were amplified by the increase of the aerodynamic forces. and thus the liquid sheet disintegrated near from the injector exit. Finally, the measured breakup length of swirl type injector according to the ambient gas density and $We_l$, was compared with the result by the linear instability theory. We found that the corrected breakup length relation derived from linear instability theory considering the attenuation of sheet thickness agrees well with our experimental results.

• Proceedings of the Korea Concrete Institute Conference
• /
• 2005.11a
• /
• pp.259-262
• /
• 2005

This paper deals with the shear strengthening effect of RC beams strengthened with carbon fiber sheets. Fifteen strengthened RC beams(including control beam) were experimentally evaluated to determine improvements in shear strength. The major parmeters of experiment variables are fiber sheet strengthening ratios and strengthening methods of fiber sheet(I-S, I-W, U-S, U-W type). Reinforced concrete beams strengthened with carbon fiber sheets were tested under the combined control of load. Considering strengthening ratios and strengthening methods of fiber sheet, shear capacity and failure mode of test specimens were evaluated. The results show that shear capacity of beams strengthened with fiber sheet is about $28.82\%$ in IS type, $20.49\%$ in IW type, $26.04\%$ in US type, $28.70\%$ in UW type higher than the strength of control beam.

• Journal of the Korean Society of Fisheries and Ocean Technology
• /
• v.32 no.4
• /
• pp.457-464
• /
• 1996

The vibration damping of various multilayer damping sheet with different constraining layer and viscoelastic layer were investigated by Rheovibron and vibration test. Damping increased as dynamic loss tangent increased. Constrained type damping sheet showed better damping than extensional type damping sheet. Aluminum foil attached asphalt impregnated paper pad showed best damping.