• Title/Summary/Keyword: Pad structure

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Field Test on the Rigidities of Substructures of High Speed Railway Bridges (고속철도교량 하부구조 강성도에 관한 현장실험)

  • Chin Won-Jong;Choi Eun-Suk;Kwark Jong-Won;Kang Jae-Yoon;Cho Jeong-Rae;Kim Byung-Suk
    • Journal of the Korean Society for Railway
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    • v.9 no.1 s.32
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    • pp.118-124
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    • 2006
  • SThe rigidities of bridge substructures are the important data in the rail-bridge interaction analysis in Korean High -Speed Railway. This experimental study is being performed because of followings. 1) More correct longitudinal stiffness of the structure including substructure should be considered in the calculation of stresses in rails. 2) There are many uncertainties in the design and construction of the piers and foundations. 3) Actual guideline for the rigidities of piers and foundations in the design is necessary. 4) Measurement on the rigidity of pier according to the types of piers, foundations and soil-conditions is needed. Curve for estimating the total rigidity of substructure will be obtained through this and further experimental studies. It may be used in the analysis of Korean High-Speed Railway bridge and then, longitudinal stresses in the rails can be estimated more accurately. One pair of piers, which consist of pot-bearing for fixed support and pad-bearing for movable support, are loaded by steel frame devices with steel wire ropes and hydraulic jack. The responses which are measured at each loading stages in those field tests are displacements and tilted angles on the top and bottom of piers. This study is being performed testing and analysis about several piers in the construction field.

The Anti-hyperlipidemic Effect and Constituents of the 19${\alpha}$-Hydroxyursane-type Triterpenoid fraction Obtained from the Leaves of Rusus crataegifolius

  • Nam, Jung-Hwan;Jung, Hyun-Ju;Tapondjou, Leon Azefack;Lee, Kyung-Tae;Choi, Jong-Won;Kim, Won-Bae;Park, Hee-Juhn
    • Natural Product Sciences
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    • v.13 no.2
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    • pp.152-159
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    • 2007
  • To demonstrate anti-hyperlipidemic activity of the 19${\alpha}$-hydroxyursane-type triterpenoid (19${\alpha}$-HUT)-rich fraction, this fraction was prepared from the extract of Rubus crataegifolius leaves. This fraction was found to have anti-hyperlipidemic effect in a high fat diet-induced rat model from the observation of reduction of abdominal fat pad weights, atherogenic index and hypercholesterolemia at 30 and 60 mg/kg (p.o.) The 19${\alpha}$-HUT fraction was subjected to SiO$_2$, ODS, and/or Sephadex LH-20 column chromatography to yield a new triterpenoid (1) called pomolic acid ester along with nine known triterpenoids which are all 19${\alpha}$-HUTs: euscaphic acid (2), tormentic acid (3), 23-hydroxytormentic acid (4), kaji-ichigoside F$_1$ (5), rosamultin (6), niga-ichigosides F$_1$ (7) and F$_2$ (8), suavissimoside F$_1$ (9) and coreanoside F$_1$ (10). The structure of compound 1 was established as 28-O-formyl-3,19-dihydroxyurs-12-en-28-oic acid on the basis of 2D-NMR spectroscopic data and mass spectrum. Compound 1 was isolated for the first time from natural sources.

Effect of Space Fabric Type Air Insole Pressure difference on Balance to Normal Adults (공간직물형 에어 인솔의 공기압 차이가 젊은 성인의 균형 능력에 미치는 영향)

  • Kim, Gi-Chul;Lee, Jeon-Hyeong;Kim, Sang-Su;Nam, Hue-Hyeong
    • PNF and Movement
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    • v.13 no.1
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    • pp.47-53
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    • 2015
  • Purpose: This study examined the effects of space fabric type air insole pressure differences on young adults' dynamic balance ability. Method: The subjects of this study were 17 young female adults without musculoskeletal system disease. Balance ability was measured by dividing the subjects into three groups: an experimental group which did not wear an air insole (insole-off group), an experimental group which wore an air insole to which air pressure of $0.55kg/cm^2$ was applied (insole-0.55 group), and an experimental group which wore an air insole to which air pressure of $0.75kg/cm^2$ was applied (insole-0.75 group). For dynamic balance, the subjects stood on a balance pad, and perimeter length and medium speed were measured three times. The averaged values were recorded and statistically processed. Result: There were significant differences in average speed, and the insole-0.75 group's average speed decreased compared to the insole-off group and the insole-0.55 group. Although the total movement distance did not statistically differ, the insole-75 group's movement distance decreased compared to the insole-off group and the insole-0.55 group. Conclusion: Application of a space fabric type air insole, in particular insole-0.75, was helpful in improving balance ability. This is considered to occur because the space fabric structure was conducive to decreasing sway and producing balance.

Analysis of Integration Factor Effect in Dynamic-Structure-Fluid-Heat Coupled Time Transient Staggered Integration Scheme for Morton Effect Analysis (모튼이펙트 해석을 위한 동역학-구조-유체-열전달 시간과도응답 연성해석 시차적분법에서 시상수 효과 분석)

  • Suh, Junho;Jeung, Sung-Hwa
    • Tribology and Lubricants
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    • v.35 no.1
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    • pp.77-86
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    • 2019
  • The present study focuses on the effect of staggered integration factor (SIF) on Morton effect simulation results. The Morton effect is a synchronous rotordynamic instability problem caused by the temperature differential across the journal in fluid film bearings. Convection and conduction of heat in the thin film displaces the hot spot, which is the hottest circumferential position in the thin film, from -20 to 40 degrees ahead of the high spot, where the minimum film clearance is experienced. The temperature differential across the journal causes a bending moment and the corresponding thermal bow in the rotating frame acts like a distributed synchronous excitation in the fixed frame. This thermal bow may cause increased vibrations and continued growth of the synchronous orbit into a limit cycle. The SIF is developed assuming that the response of the rotor-lubricant-bearing dynamic system is much quicker than that of the bearing-journal thermal system, and it is defined as the ratio between the simulation time of the thermal system and the rotor-spinning period. The use of the SIF is unavoidable for efficient computing. The value of the SIF is chosen empirically by the software users as a value between 100 and 400. However, the effect of the SIF on Morton effect simulation results has not been investigated. This research produces simulation results with different values of SIF.

Ka-Band Variable-Gain CMOS Low Noise Amplifier for Satellite Communication System (위성 통신 시스템을 위한 Ka-band 이득제어 CMOS 저잡음 증폭기)

  • Im, Hyemin;Jung, Hayeon;Lee, Jaeyong;Park, Sungkyu;Park, Changkun
    • Journal of the Korea Institute of Information and Communication Engineering
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    • v.23 no.8
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    • pp.959-965
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    • 2019
  • In this paper, we design a low noise amplifier to support ka-band satellite communication systems using 65-nm RFCMOS process. The proposed low noise amplifier is designed with high-gain mode and low-gain mode, and is designed to control the gain according to the magnitude of the input signal. In order to reduce the power consumption, the supply voltage of the entire circuit is limited to 1 V or less. We proposed the gain control circuit that consists of the inverter structure. The 3D EM simulator is used to reduce the size of the circuit. The size of the designed amplifier including pad is $0.33mm^2$. The fabricated amplifier has a -7 dB gain control range in 3 dB bandwidth and the reflection coefficient is less than -6 dB in high gain mode and less than -15 dB in low gain mode.

The Design of a Crutch as Mobility Aids for the Handicapped in the Lower Extremity (하지 장애인의 보행보조를 위한 목발 디자인 연구)

  • Yang, Sung Ho;Oh, Kwang Myung
    • Design Convergence Study
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    • v.17 no.3
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    • pp.55-70
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    • 2018
  • This study was conducted as a part of long-term project on the development of a set of design guidelines for a crutch as mobility aids for the handicapped in the lower extremity and the suggestion a practical solution for a crutch design. The purpose of this study is to develop a design of a crutch and a set of prototypes that reflects the characteristics of crutch-gait and has a realistic possibility for mass production-based industry. TOGO, a axillary crutch as the result of this study, shows a number of characteristics distinguished from ordinary crutches. These are (1)Minimize the shock associated with planting of the crutch tips by improving the form and structure of crutch tip and axillary pad, (2)Ergonomically designed crutch in accordance with users' body movement while walking on crutches, (3)Easy length control to maximize mobility and maneuverability by changing the cross section of the crutch revolutionary, (4)Minimize possibilities of safety hazards, and (5)Attractive shape of the crutch to keep user self-esteem. The revolutionary crutch derived from this study results has been patented, and the company is seeking to mass-produce and find ways to commercialize it after reviewing the potential problems that may arise in the mass production environment.

Development of the 3D Knee Protector for Yoga (요가용 3차원 무릎보호대 개발 및 평가)

  • Jung, Hyunju;Lee, Heeran;Chung, Ihn Hee
    • Journal of the Korean Society of Clothing and Textiles
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    • v.46 no.4
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    • pp.657-671
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    • 2022
  • This study aims to develop three dimensional (3D) yoga knee protectors that provide excellent wearing comfort. Three types of pads were modeled using 3D human data: two types of 3.0-cm-wide pads separated into top and bottom with thicknesses of 0.1 cm (TPU-1: A) and 0.2 cm (TPU-2: B); and one type with three 0.2-cm-thick separated panels (TPU-S: C). Based on these models, five knee protectors were developed using 3D patterning and 3D printing. Types A, B, and C were integrated with 0.6-cm neoprene pads. Type D was fabricated with a donut-shaped 0.6-cm neoprene pad inserted, while Type E consisted of two discrete 0.6-cm neoprene pads embedded in the protector's upper and lower sides. Wearing comfort was evaluated in terms of fit, pressure, and cushioning while in a standing and kneeling position and while in motion. The findings suggest that the fabricated knee protectors were evaluated as comfortable to the individuals with knee pain, rather than those without knee pain. The individuals with knee pain preferred the soft pads made of neoprene positioned around the knee (NEO-S: E), while those without knee pain favored the cushioned pads with a pattern structure maintained by thin 3D-printed pads (TPU-1: A).

Fine Structural Analysis of the Attachment Devices in the Jumping Spider Plexippus setipes (깡충거미 표면 접착장치의 미세구조 분석)

  • Moon, Myung-Jin;Park, Jong-Gu
    • Applied Microscopy
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    • v.39 no.2
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    • pp.149-156
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    • 2009
  • Fine structure of the dry adhesion system in the tarsal appendages of the jumping spider Plexippus setipes (Araneae: Salticidae) with examined using field emission scanning electron microscope (FESEM). The jumping spiders have the distinctive attachment apparatus for adhesion on smooth dry surface without sticky fluids. They attach to rough substrates using tarsal claws, however attachment on smooth surfaces is achieved by means of a tuft-like hair called a scopula. All eight legs have the scopulae with a pair of claws on the tip of feet, and each scopula is composed of two groups of setae that are capable of dry adhesion on smooth surface. The apex of each seta is flattened pad bearing many specialized adhesive setules on one side. The cuticular sensillae are interspersed at the dorsal surface of the seta. It has been revealed by this research that the contact area of the setule is always a triangular shape, and these cuticular surfaces are connected by the elongated stalks from the underlying setae. Moreover, adhesion between the numerous setules and the setae was prevented by the microscopic hairs, since these were interspersed on the upper side of the setae.

Fabrication of MEMS Test Socket for BGA IC Packages (MEMS 공정을 이용한 BGA IC 패키지용 테스트 소켓의 제작)

  • Kim, Sang-Won;Cho, Chan-Seob;Nam, Jae-Woo;Kim, Bong-Hwan;Lee, Jong-Hyun
    • Journal of the Institute of Electronics Engineers of Korea SD
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    • v.47 no.11
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    • pp.1-5
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    • 2010
  • We developed a novel micro-electro mechanical systems (MEMS) test socket using silicon on insulator (SOI) substrate with the cantilever array structure. We designed the round shaped cantilevers with the maximum length of $350{\mu}m$, the maximum width of $200{\mu}m$ and the thickness of $10{\mu}m$ for $650{\mu}m$ pitch for 8 mm x 8 mm area and 121 balls square ball grid array (BGA) packages. The MEMS test socket was fabricated by MEMS technology using metal lift off process and deep reactive ion etching (DRIE) silicon etcher and so on. The MEMS test socket has a simple structure, low production cost, fine pitch, high pin count and rapid prototyping. We verified the performances of the MEMS test sockets such as deflection as a function of the applied force, path resistance between the cantilever and the metal pad and the contact resistance. Fabricated cantilever has 1.3 gf (gram force) at $90{\mu}m$ deflection. Total path resistance was less than $17{\Omega}$. The contact resistance was approximately from 0.7 to $0.75{\Omega}$ for all cantilevers. Therefore the test socket is suitable for BGA integrated circuit (IC) packages tests.

Analytical study to the Brake Lever in Basic Brake System for Railway Vehicle (철도차량용 기초제동장치의 제동레버 강도에 대한 해석적 연구)

  • Park, Su-Myung;Park, Jae-young
    • Journal of the Korea Academia-Industrial cooperation Society
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    • v.17 no.8
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    • pp.624-629
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    • 2016
  • A brake lever in a basic railway brake system is an important safety device that delivers braking force from the brake cylinder to the brake pad. The safety guidelines for designing rolling stock only qualitatively describe that the brake lever should have sufficient strength. Each train has a different type of brake lever. One brake lever that was designed with a factor of safety of 1.27 has failed, so the material was changed to increase the strength. Therefore, the stress distribution and weak points of the lever were identified by theoretical analysis. and structural analysis. Different brake lever designs were examined for KTX high-speed trains, which have a split-type structure, as well as for electric locomotives, which use an electric multiple unit (EMU) with a unity-type structure. A fracture test was also done to look at the relationship between the vertical stress and the bending stress during braking. The results were used to find a safety factor to apply to each train and suggest quantitative minimum guidelines. We also looked at changing the unity-type EMU brake lever to the split type under the same conditions and analyzed how much the design change affected the factor of safety.