• Fibers and Polymers
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• v.5 no.3
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• pp.230-233
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• 2004

The optimum conditions for durable press treatment of cotton fabrics using glyoxal as a nonformaldehyde crosslinking agent were investigated. Crosslinking reaction was conducted in the presence of different catalysts such as aluminum sulfate, magnesium chloride, or magnesium chloride-citric acid mixture at various mole ratios of catalyst to glyoxal. Aluminum sulfate was proven the most effective one among those used. Glycol addition into a glyoxal padding bath increased the wrinkle recovery angle(WRA) and whiteness of treated fabrics. The optimum mole ratio of glycol to glyoxal was 1:1. Diethylene glycol addition produced better overall performance to the glyoxal-crosslinked fabric compared to ethylene glycol addition.

• Journal of the Korean Institute of Electrical and Electronic Material Engineers
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• v.16 no.11
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• pp.1001-1007
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• 2003

The silicone fluids have been generally used as processing agent in silicone rubber(SIR) compounding. The addition of hydroxy silicone (HS) fluids to SIR for insulator housing material is required to meet the good electrical performance and the good processability. In this study, SIR with HS fluids was evaluated to investigate how the kinds of them affect insulation properties. The contact angle of the virgin sample of 40-HS SIR was low and its recovery rate was also slow. The recovery rate of 50-HS SIR was the highest being decreased with the viscosity increase of HS fluids. The tracking resistances and the corona aging resistance of 70-HS SIR and 1,040-HS SIR were excellent Tracking resistance depended largely on heat resistance of silicone fluids. But arc resistance didn't depend merely on the kind of silicone fluids.

• Journal of Institute of Control, Robotics and Systems
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• v.15 no.2
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• pp.240-248
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• 2009

Modem version of supersonic jet fighter aircraft must have been guaranteed appropriate controllability and stability in HAoA(High Angle of Attack). The HAoA flight control law have two parts, one is control law of departure prevention and the other is control law of departure recovery support. The control laws of departure prevention for advanced jet trainer consist of HAoA limiter, roll command limiter and rudder fader. The control laws of departure recovery support are consist of yaw-rate limiter and MPO(Manual Pitch Override) mode. The guideline of pitch rocking using MPO mode is simple, but operating skill of pitch rocking is very difficult by the pilot with inexperience of departure situation. Therefore, automatic deep stall recovery system is necessary. The system called the "Automatic Pitch Rocker System" or APRS, provided a pilot initiated automatic maneuver capable of an aircraft recoveries in situations of deep stall, speed and altitude. This paper addresses the design and validation for APRS to recovery of an deep stall without manual pitch rocking by the pilot. Also, this system is designed to recovery of speed, attitude and altitude after deep stall recovery using ATCS (Automatic Thrust Control System) and autopilot. Finally, this system is verified by real-time pilot evaluation using HQS (Handling Quality Simulator).

• The Transactions of the Korean Institute of Electrical Engineers B
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• v.48 no.8
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• pp.431-439
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• 1999

Among the variable-speed AC motor drive systems, the static slip power recovery system has been widely adopted in large power drives because a high efficiency drive can be obtained by recovering the slip power to the AC line. Although many improvements have been made in this system, several problems also remain such as the need of transformer in inverter AC side, which results in limiting speed control range and increasing the losses, production of reactive power by the control of inverter firing angle, harmonics in line currents, and so on. This paper presents the novel high performance slip power recovery system using the boost converter and small size filter in the rotor circuit, which recovers slip power of a wound rotor induction machine to AC supply efficiently with the aid of the boost converter, in which most of the problems in conventional system can be solved. The speed can be controlled by the duty ratio of the converter switch, not by inverter firing angle. As a results, the proposed system can operate in high power factor and the harmonic currents caused by the inverter and rectifier can be considerably suppressed. The validity of the proposed system verified by demonstrating the good agreement in the simulation and experimental results.

• Journal of the Korean Association of Oral and Maxillofacial Surgeons
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• v.33 no.4
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• pp.397-400
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• 2007

In an open reduction of the mandibular angle fracture, it is crucial to approximate each fracture segment as closer as possible for the reduction of the healing period. In this case report, we proposed a new technique for the mandibular angle fracture. This was designed to minimize the gap between two separated segments using mini-implants and surgical wires. Mini-implants were placed around the fracture line, followed by wire ligation to minimize the fracture gap. And then internal fixation was easily employed with plates and screws. The advantages of this technique were reduced time for operation, the promotion of healing, rapid functional recovery, and few complications.

• KOREAN JOURNAL OF CROP SCIENCE
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• v.51 no.5
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• pp.440-444
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• 2006

This study was carried out to compare the grain quality under lodging time and grade at ripening. Ripened grain ratio and 1000-grain weight were higher with lodging of plants at $45^{\circ}$ angle from the ground and increased with crop development. The number of spikelets, as well as the protein and amylose content of the grains, were higher in plants under severe or complete lodging than those under lodging at $45^{\circ}$ angle from the ground. Palatability and sensory evaluation values were higher in plants under lodging at $45^{\circ}C$ angle from the ground than those under complete lodging. Brown rice: rough rice ratio was higher with lodging of plants at $45^{\circ}C$ angle from the ground and increased with crop growth. Milling recovery and milled rice recovery were higher with lodging of plants at $45^{\circ}C$ angle from the ground, whereas chalky grain, cracked grain and damage grains were higher at complete lodging.

• Journal of the Korean Society for Aeronautical & Space Sciences
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• v.38 no.3
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• pp.207-212
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• 2010

This paper presents a spiral descending path and a landing guidance law for net-recovery of a fixed-wing unmanned aerial vehicle. The net-recovery landing flight is divided into two phases. In the first phase, a spiral descending path is designed from an arbitrary initial position to a final approaching waypoint toward the recovery net. The flight path angle is controlled to be aligned to the approaching direction at the end of the spiral descent. In the second phase, the aircraft is guided from the approaching waypoint to the recovery net using a pseudo pursuit landing guidance law. Six degree-of-freedom simulation is performed to verify the performance of the proposed landing guidance law.

• Journal of Ocean Engineering and Technology
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• v.11 no.3
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• pp.132-143
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• 1997

Removal of spilled oil over the sea and the river has become one of the urgent problem in these days. Removing oil using mechanical devices are recommended because chemical dispersion can cause the secondary contamination in the environment. In the present study a series of experiments were carried out to study the effect of working conditions of a belt type skimmer on the rate of recovery for the spilled oil. The oil chosen for the present experiment was diesel oil. Three different situations, namely, upward, downward, up-and-downward pickup have been investigated for various contact angles, belt speeds and oil thicknesses. The results show that the rate of oil recovery for the case of downward pickup with a contact angle of 45.deg. shows the highest among all the conditions. For the removal of spilled diesel oil the optimal belt speed can be found as the critical value to reach the saturated pickup rate for a given oil thickness. The recovery rate of bunker C oil shows 4-6 times higher than that for diesel oil. And the optimal belt speed for bunker C oil can be found less than that for diesel oil for the same slick thickness.

• Elastomers and Composites
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• v.46 no.1
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• pp.45-53
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• 2011

The effect of the silane coupling agent, bis(triethoxysilypropyl)tetrasulfide (TESPT), on mechanical properties of a silica-filled NBR compound for oilseal was investigated. Curing behavior and crosslinking density of the compounds were measured using ODR (oscillating disk rheometer) and swelling ratio in toluene. UTM (universal testing machine) and shore A hardness tester were used in order to study the characteristics of mechanical properties of original vulcanizates and aged ones with heated air and ASTM No. 3. oil. Recovery of elasticity which influences the performance and service life of oilseal was investigated by giving bending deformation to vulcanizates in aging condition. After bending aging test, recovery distance was measured and calculated angle of recovery from it. TR (temperature retraction) test was performed on these vulcanizates to determine the low temperature recovery behavior. Wear resistance was measured by Taber type abrasion tester. In addition, SEM was used to characterize the morphology of the worn surface of vulcanizates. The result showed that addition of TESPT into silica-filled compound improves not only compound flow-ability, interaction between NBR and silica and crosslinking density, but also hardness, 100% modulus, recovery of elasticity, wear resistance, heat resistance and ASTM No.3 oil resistance of vulcanizates.

• Journal of Advanced Marine Engineering and Technology
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• v.26 no.4
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• pp.450-456
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• 2002

Die desig for manufacturing hooks from steel wires has been depended on empirical procedures based on trial and error method. To design die, at first the curvature and bending angle of hook are computed by using AutoCAD and developed program which is composed of Visual Basic. Then spring back should be considered because the elastic recovery of material is very important in bending process. In this study, bending analysis of elastic-plastic materials is applied to predict curvature of hook and spring back. Therefore, systematic procedure of die design for bending hook is achieved to consider elastic recovery in terms of hook shapes. Experimental results are good agreement with calculated results.