• The Journal of the Institute of Internet, Broadcasting and Communication
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• v.16 no.2
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• pp.145-150
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• 2016

In this paper, we proposes a DTV indoor receiving antenna with a gap sleeve monopole structure. The proposed antenna uses a basic structure of a sleeve monopole and gap sleeve. To optimize antenna, we have adjusted the gap between monopole and sleeve, the gap between sleeve and ground. In order to confirm the property of antenna parameters, it was used a commercial software, HFSS. For the antenna fabrication, a FR4 dielectric substrate which has a dielectric constant of 4.7 was used. The size of the antenna was $213mm{\times}40mm{\times}1.6mm$. Frequency band of the fabricated antenna was 432MHz ~ 827MHz, and the bandwidth was 395MHz. The maximum gain of the antenna was 2.19dBi. Consequently, it was confirmed the possibility of practical application of the DTV indoor receiving antenna with a gap sleeve monopole structure.

• Structural Engineering and Mechanics
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• v.66 no.6
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• pp.783-792
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• 2018

This paper presents a detailed theoretical study of the sleeved compression members based on a mechanical model. In the mechanical model, the core protrusion above sleeve and the contact force between the core and sleeve are specially taken into account. Via the theoretical analyses, load-displacement relationships of the sleeved compression members are obtained and verified by the experimental results. On the basis of the core moment distribution changing with the increase of the applied axial load, failure mechanism of the sleeved compression members is assumed and proved to be consistent with the experimental results in terms of the failure modes and the ultimate bearing capacities. A parametric study is conducted to quantify how essential factors including the core protrusion length above sleeve, stiffness ratio of the core to sleeve, core slenderness ratio and gap between the core and sleeve affect the mechanical behaviors of the sleeved compression members, and it is concluded that the constrained effect of the sleeve is overestimated neglecting the core protrusion; the improvement of ultimate bearing capacity for the sleeved compression member is considered to be decreasing with the decrease of the core slenderness ratio and for the sleeved compression member with core of small slenderness ratio, small gap and small stiffness ratio are preferred to obtain larger ultimate bearing capacity and stiffness.

• Journal of the Korean Society for Aeronautical & Space Sciences
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• v.46 no.6
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• pp.487-495
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• 2018

Experimental analysis of the spray characteristics of the movable sleeve injector, which can simultaneously control the area of the annular gap and the pintle gap, has been studied and a method for controlling the uniform performance over a wide thrust range has been studied. It is confirmed that the design flow rate is not satisfied when the constant pressure difference is set regardless of the opening distance of the sleeve. In order to improve this, the differential pressure in the annular gap and the pintle gap was applied differently according to the opening distance. It was confirmed that the design flow rate was satisfied within the operating range and thrust control was linear from 25% to 100% in linear sleeve area.

• The Korean Journal of Community Living Science
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• v.24 no.4
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• pp.457-469
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• 2013

The purpose of this study is to quantitatively analyze the impacts of the distribution of easing contraction of the sleeve on the external appearance of bodice and sleeve through virtual clothing simulation. Virtual clothing is conducted by differentiating the sleeve easing in accordance with the experimental condition of bodice and sleeve that are followed by draping. And then the evaluation is carried out. As a result of an analysis of the similarity between the virtual garment and the actual clothing, the whole external appearance of the bodice and sleeve was expressed similarly. The external appearance according to the distribution of easing contraction got better as the easing contraction of sleeve was concentrated on sleeve cap in front while the appearance was better at the back as it was more gently distributed than in the front. In a comparison of armhole form, the clothing of which the top of it was most similar to S0 was S4 in which the gap between the armhole and the arm was the least and the front and rear silhouette fell relatively well. In a comparison between the position of bust circumference line and that of the sleeve base line, the front of the sleeve matched the bust circumference line as the easing contraction was distributed close to the center of the sleeve cap while in the back, the sleeve base line and the bust circumference line matched when some easing contraction ratio was added close to the armpit point. The cross section figures of garment space of the shoulder, the margin was evenly distributed in S4 or S5 with differing distributions of easing contraction in the front and the back. This study is significant in that it supplies the objective baseline data which makes a novice more able to make a good external appearance of the sleeve.

• The Journal of the Institute of Internet, Broadcasting and Communication
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• v.20 no.5
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• pp.135-141
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• 2020

This paper summarizes the data of a monopole antenna with a sleeve structure that can be applied in various ways. Sleeve monopole antennas have broadband characteristics and are used for multi-frequency applications. The sleeve monopole antenna is composed of a vertical conductor, which is a radiator, and a sleeve having the same structure as a coaxial cable. The sleeve acts as a radiator and an open stub. The length of the sleeve should be 1/3~2/3 of the total length of the antenna. A monopole antenna having a sleeve structure is applicable to a vehicle wiper antenna. In addition, the case of applying this antenna to a broadband sleeve antenna using a loading coil, a broadband printed sleeve monopole antenna for an ISM band, a gap sleeve and a double sleeve, and a UWB planar monopole antenna using half cutting was summarized and analyzed in terms of structure and broadband.

• Journal of Magnetics
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• v.21 no.3
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• pp.405-412
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• 2016

In general, surface mounted PM synchronous motors (SPMSMs) are mainly adopted as a driving motor for high-speed applications, because they have high efficiency and high power density. However, the SPMSMs have some weak points such as the increase of magnetic reluctance and additional losses as a consequence of using a non-magnetic sleeve. Especially, the magneto-motive force (MMF) in the air-gap of the SPMSMs is weakened due to the magnetically increased resistance. For that reason, a large amount of PM is consumed to meet the required MMF. Nevertheless, it cannot help using the sleeve in order to maintain the mechanical integrity of a rotor assembly in high-speed rotation. Thus, in this paper, a multi-layer interior PM synchronous motor (IPMSM) not using the sleeve is presented and designed as an alternative of a SPMSM. Both motors are evaluated by test results based on a variety of characteristics required for an air blower system of a fuel cell electric vehicle.

• The Journal of the Institute of Internet, Broadcasting and Communication
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• v.16 no.1
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• pp.215-220
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• 2016

In this paper, a wideband antenna accomplished by adding a double sleeve of a rectangular planar monopole structure is proposed. In order to impedance matching of proposed antenna, the antenna performance was improved by adding two gap sleeves and outer sleeve for double sleeve structure. HFSS simulator of ANSYS corp. was used in order to confirm the antenna parameter characteristic. According to the simulation results, the VSWR was less than 2 for the range of 2.5GHz~10.5GHz. The frequency bandwidth is 8GHz. The frequency range of the actual fabricated antenna was 2.92GHz~10.32GHz, the frequency bandwidth is 7.4GHz. The measured radiation pattern frequency is 3GHz, 6GHz and 9GHz. The results are similar with dipole antenna pattern in all frequency. The antenna size is $40{\times}40mm^2$. The utilization possibility of the ultra-wideband planar monopole antenna could be confirmed according to compare and analyze the simulation and measurement data.

• The Journal of the Institute of Internet, Broadcasting and Communication
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• v.17 no.2
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• pp.257-262
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• 2017

In this paper, we proposed a rectangular planar monopole antenna with a double sleeve that applied to a half-cut and a discontinuous feed structure. A rectangular planar monopole antenna with a double sleeve was cut in half along the magnetic symmetry line, and impedance matching was achieved by a discontinuous structure was applied to a feeder and by adjusting the double sleeve gap. We used the HFSS simulator of ANSYS company to confirm the antenna parameter property, and the antenna size was $21{\times}40mm^2$. In the proposed antenna, the simulation frequency range with VSWR of 2 or less was 2.6GHz to 10.25GHz. The bandwidth was 7.65GHz. The frequency range of the fabricated antenna was 3.3GHz to 9.75GHz, and the bandwidth was 6.45GHz. The measured radiation pattern frequencies were 3.5GHz, 5.5GHz, 7.5GHz, and 9.5GHz. A radiation pattern similar to the dipole antenna pattern was obtained at all frequencies.

• Computers and Concrete
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• v.12 no.2
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• pp.131-149
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• 2013

Various types of reinforcement splicing methods have been developed and implemented in reinforced concrete construction projects for achieving the continuity of reinforcements. Due to the complicated reinforcement arrangements and the difficulties in securing bar spacing, the traditional lap splicing method, which has been widely used in reinforced concrete constructions, often shows low constructability and difficulties in quality control. Also, lap spliced regions are likely to be over-reinforced, which may not be desirable in seismic design. On the other hand, mechanical splicing methods can offer simple and clear arrangements of reinforcement. In order to utilize the couplers for the ribbed-deformed bars, however, additional screw processing at the ends of reinforcing bars is typically required, which often lead to performance degradations of reinforced concrete members due to the lack of workmanship in screw processing or in adjusting the length of reinforcing bars. On the contrary, the use of screw-ribbed reinforcements can easily solve these issues on the mechanical splicing methods, because it does not require the screw process on the bar. In this study, the mechanical coupler suitable for the screw-ribbed reinforcements has been developed, in which any gap between the reinforcements and sleeve device can be removed by grouting high-flow inorganic mortar. This study presents the uniaxial tension tests on the screw-ribbed reinforcement with the mechanical sleeve devices and the cyclic loading tests on RC columns with the developed coupler. The test results show that the mechanical sleeve connection developed in this study has an excellent splicing performance, and that it is applicable to reinforced concrete columns with a proper confinement by hoop reinforcement.

• Proceedings of the KIEE Conference
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• 2000.07c
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• pp.2020-2022
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• 2000

The cross-linked polyethylene(herein after XLPE) insulated power cable emit the methane($CH_4$)gas in the course of chemical cross-linking process. The general stranded conductor easily discharge this methane gas through the gap of each stranded wires. But the special stranded conductor that filled with semi-conducting rubber compound to prevent water penetration which is applied to water proof type of cable(22.9kV CN/CV-W), disturb the methane gas emission. The pre-mold type cable joint shall be expanded gradually by emit of gas left in XLPE insulation. For example, sometimes the corona problem outbreak on a new power distribution line, resulted from the gap between the sleeve and semi-conductive layer of cable joint. If above mentioned problem especially happened on the way of operating. We have to shut down the line and try to discharge the methane gas in cable joint. In this point, we would like to explain the mechanism of methane gas & cable joint and our test result briefly. At last, we are pleased to introduce the solution for preventing reoccurrence of this problem.