• 제목/요약/키워드: stabilizer-free

검색결과 30건 처리시간 0.088초

차량용 스테빌라이져 링크의 유격과 이상소음 발생의 상관관계 (Relationships between Free Gaps and Abnormal Noises of Vehicle Stabilizer Links)

  • 한창완;김한종;유영재;박성훈
    • 한국자동차공학회논문집
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    • 제25권1호
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    • pp.28-34
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    • 2017
  • The vehicle stabilizer link is one of the suspension components that reduces the bumping and rolling during vehicle driving. However, this stabilizer link could be a source of the abnormal noises when its free gaps have higher than normal values. Therefore, the current study aims at investigating the quantitative relationships between the abnormal noises and free gaps of the vehicle stabilizer links, as well as the length of time that the vehicle stabilizer links could be used without generating abnormal noises. In this study, the abnormal noises were measured based on the magnitude of the stabilizer link vibration, while the free gaps were quantified through the force-displacement curves of the stabilizer links. Harsh durability tests were also conducted in order to quantify the operating cycles of the stabilizer links before generating the abnormal noises, along with the concomitant measurements of the free gaps. The current results showed that the abnormal noises of the stabilizer links were detected when its free gaps were larger than 0.12 mm. However, the free gaps of the stabilizer links, which are bigger than 0.1 mm, produced the abnormal noises at 1.5 million cycles under harsh durability test conditions. A parametric study in the future that would reflect the different shapes and sizes of the stabilizer links for diverse vehicles could determine more generalized relationships between the abnormal noises and free gaps of the vehicle stabilizer links.

Stabilizer-free 초전도 선재를 이용한 한류 소자 제작 및 특성 시험 (Fabrication and characterization of fault current limiting devices made of stabilizer-free coated conductors)

  • 임성우;박충렬;유승덕;김혜림;현옥배
    • 한국전기전자재료학회:학술대회논문집
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    • 한국전기전자재료학회 2009년도 하계학술대회 논문집
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    • pp.371-371
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    • 2009
  • For the application of superconducting wires to fault current limiting devices, it is required that they have a high rated voltage when a fault occurs. Stabilizer-free coated conductors, particularly, shows a good performance for the high rated voltage, which is beyond 0.6 V/cm. In this study, using the stabilizer-free coated conductors, we made fault current limiting devices and examined their characteristics. Fault current limiting devices were fabricated with a shape of the cylinder of a mono-filar coil winding. Stabilizer-free coated conductors were wound along the mono-filar coil line and the terminal parts between the wire and metal were soldered using In solder. Two kinds of devices were fabricated by a different method in the terminal joint, one was made by a soldering and the other was made by a soldering-free joint. Critical currents and resistance at the joint parts were measured. In addition, long-time current flowing tests were also carried out for the characterization of the fault current limiting devices.

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Dispersion Polymerization of Styrene Employing Lyophilic Comonomer in the Absence of Stabilizer: Synthesis of Impurity-free Microspheres

  • Han, Hye-Kyung;Lee, Jeong-Woo;Hong, Jin-Ho;Shim, Sang-Eun
    • Macromolecular Research
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    • 제17권7호
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    • pp.469-475
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    • 2009
  • We investigated the feasibility of dispersion polymerization without any stabilizer, which has been considered essential for ensuring colloidal stability. By employing small amounts of a lyophilic comonomer, 4-vinyl pyridine, styrene was successfully polymerized by dispersion polymerization in aqueous alcohol without stabilizer to afford stable poly(styrene-co-4-vinyl pyridine) copolymer microspheres. The stable microspheres were produced in the 4-vinyl pyridine range of 2-15 wt% to styrene. Without 4-vinyl pyridine, severely coagulated particles were obtained, implying that the poly(4-vinyl pyridine) moiety endowed colloidal stability. The polymerization kinetics, behavior, and properties of the ultimate particles showed general features of dispersion polymerization. The study results suggest that stabilizer- tree dispersion polymerization is possible, thereby facilitating the synthesis of impurity(stabilizer)-tree polymer particles.

자세제어장비 성능시험을 위한 자유항주 모형선 개발 (Development of Free Running Model Ship for Evaluation of the Performance of Anti-Rolling Devices)

  • 윤현규;이경중;손남선;양영훈
    • 한국항해항만학회:학술대회논문집
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    • 한국항해항만학회 2004년도 추계학술대회
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    • pp.33-39
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    • 2004
  • 파랑중을 운항하는 선박은 항상 파도의 영향을 받아 운동을 하게 된다. 여러방향의 운동형태 중에서 횡동요가 화물의 안전 및 선원의 피로도에 가장 큰 영향을 미친다. 따라서 횡동요가 문제가 되는 선박에는 횡동요 저감 장치의 장착이 늘어나고 있는 추세이다. 본 연구에서는 핀 스태빌라이저(Fin stabilizer)와 이동질량 감요장치(Moving weight stabilizer)의 성능시험을 위하여 자유항주 모형선을 개발하였다. 또한 자세제어장비 성능시험 절차를 정립하고, 개발한 자유항주 모형선올 통하여 성능시험을 수행하였다.

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FGC계 고화재를 이용한 Soilcrete 배합설계에 관한 연구 (A Study on the mix design for the Soilcrete by Using FGC Soil Stabilizer)

  • 천병식;고갑수;김진춘;하상욱
    • 한국지반공학회:학술대회논문집
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    • 한국지반공학회 1999년도 가을 학술발표회 논문집
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    • pp.293-300
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    • 1999
  • Soilcrete has been the traditional material for the paving and soft ground improvement techniques. But because the durability is not excellent and the quality is not homogeneous, it has not been used for the various purposes up to date. And because the quality of soilcrete is apt to be changed by the content of water and soil stabilizer, and the kind of soil and soil stabilizer, it is not free of cares. But with the increase of naturally oriented needs for the light traffic road such as pedestrian roads of the garden, golf courses and sidewalks, the cases of soilcrete paving has been increased recently. This study aims at making the reference table of the mix design in accordance with the required design specifications for the soilcrete admixtures by the FGC soil stabilizer by using the statistical experiment method. The treated soil is the clay which are widely spreaded in Korea. As the results of this study we can derive the effective reference mix design table for the clay soil treated by the FGC soil stabilizer in accordance with the compressive strength of 50∼200kg/$\textrm{cm}^2$ soilcrete with respect to the contents of water, soil stabilizer and fine sand.

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Power System Stabilizer using the Free Model

  • Kim, Ho-Chan;Oh, Seong-Bo;Lee, Kwang-Yeon
    • 제어로봇시스템학회:학술대회논문집
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    • 제어로봇시스템학회 2001년도 ICCAS
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    • pp.139.3-139
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    • 2001
  • The free-model concept is introduced as an alternative intelligent system technique to design a controller with input and output data only. The idea of free model comes from the Taylor series approximation, where an output can be estimated when such data as position, velocity, and acceleration are known. The parameters in the free model can be estimated using the input-output data and a controller can be designed based on the free model. The free model thus developed is shown to be controllable, observable, and robust. The accuracy of the free-model approximation can be improved by increasing the observation window and the order of the free model. The LQR method is applied to the free model to design power system stabilizers ...

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MULTIPLICITY-FREE ACTIONS OF THE ALTERNATING GROUPS

  • Balmaceda, Jose Maria P.
    • 대한수학회지
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    • 제34권2호
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    • pp.453-467
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    • 1997
  • A transitive permutation representation of a group G is said to be multiplicity-free if all of its irreducible constituents are distinct. The character corresponding to the action is called the permutation character, given by $(1_H)^G$, where H is the stabilizer of a point. Multiplicity-free permutation characters are of interest in the study of centralizer algebras and distance-transitive graphs, and all finite simple groups are known to have such characters. In this article, we extend to the alternating groups the result of J. Saxl who determined the multiplicity-free permutation representations of the symmetric groups. We classify all subgroups H for which $(1_H)^An, n > 18$, is multiplicity-free.

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타입에 따른 무유도 권선형 코일의 한류 특성연구 및 자장해석 (A study on the current limiting characteristics and magnetic analysis of the non-inductively wound coil)

  • 장재영;박동근;장기성;나진배;김원철;정윤도;고태국
    • 한국초전도ㆍ저온공학회논문지
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    • 제11권1호
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    • pp.25-29
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    • 2009
  • To reduce the power loss in normal state, non-inductively wound high temperature superconducting (HTS) coils are used for fault current limiter (FCL) application. Non-inductively wound coils can be classified into two types: solenoid type and pancake type. These two types have different electrical and thermal and mechanical characteristics due to their winding structure difference. This paper deals with the current limiting characteristics, magnetic field analysis of the two coils. Simulation using finite element method (FEM) was used to analyze the magnetic field distribution and inductance of the coils. Short circuit test using stabilizer-free coated conductor (CC) was also carried out. We can compare the characteristics of the two types of coil by using the data obtained from simulation and short circuit test. We confirmed the feasibility of FCL application by the analysis about the characteristics of non-inductively wound coil using CC.

A Simultaneous Perturbation Stochastic Approximation (SPSA)-Based Model Approximation and its Application for Power System Stabilizers

  • Ko, Hee-Sang;Lee, Kwang-Y.;Kim, Ho-Chan
    • International Journal of Control, Automation, and Systems
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    • 제6권4호
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    • pp.506-514
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    • 2008
  • This paper presents an intelligent model; named as free model, approach for a closed-loop system identification using input and output data and its application to design a power system stabilizer (PSS). The free model concept is introduced as an alternative intelligent system technique to design a controller for such dynamic system, which is complex, difficult to know, or unknown, with input and output data only, and it does not require the detail knowledge of mathematical model for the system. In the free model, the data used has incremental forms using backward difference operators. The parameters of the free model can be obtained by simultaneous perturbation stochastic approximation (SPSA) method. A linear transformation is introduced to convert the free model into a linear model so that a conventional linear controller design method can be applied. In this paper, the feasibility of the proposed method is demonstrated in a one-machine infinite bus power system. The linear quadratic regulator (LQR) method is applied to the free model to design a PSS for the system, and compared with the conventional PSS. The proposed SPSA-based LQR controller is robust in different loading conditions and system failures such as the outage of a major transmission line or a three phase to ground fault which causes the change of the system structure.

Efficacy of genotype-matched Newcastle disease virus vaccine formulated in carboxymethyl sago starch acid hydrogel in chickens vaccinated via different routes

  • Mahamud, Siti Nor Azizah;Bello, Muhammad Bashir;Ideris, Aini;Omar, Abdul Rahman
    • Journal of Veterinary Science
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    • 제23권4호
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    • pp.25.1-25.14
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    • 2022
  • Background: The commercially available Newcastle disease (ND) vaccines were developed based on Newcastle disease virus (NDV) isolates genetically divergent from field strains that can only prevent clinical disease, not shedding of virulent heterologous virus, highlighting the need to develop genotype-matched vaccines Objectives: This study examined the efficacy of the NDV genotype-matched vaccine, mIBS025 strain formulated in standard vaccine stabilizer, and in carboxymethyl sago starch-acid hydrogel (CMSS-AH) following vaccination via an eye drop (ED) and drinking water (DW). Methods: A challenge virus was prepared from a recent NDV isolated from ND vaccinated flock. Groups of specific-pathogen-free chickens were vaccinated with mIBS025 vaccine strain prepared in a standard vaccine stabilizer and CMSS-AH via ED and DW and then challenged with the UPM/NDV/IBS362/2016 strain. Results: Chickens vaccinated with CMSS-AH mIBS025 ED (group 2) developed the earliest and highest Hemagglutination Inhibition (HI) NDV antibody titer (8log2) followed by standard mIBS025 ED (group 3) (7log2) both conferred complete protection and drastically reduced virus shedding. By contrast, chickens vaccinated with standard mIBS025 DW (group 5) and CMSS-AH mIBS025 DW (group 4) developed low HI NDV antibody titers of 4log2 and 3log2, respectively, which correspondingly conferred only 50% and 60% protection and continuously shed the virulent virus via the oropharyngeal and cloacal routes until the end of the study at 14 dpc. Conclusions: The efficacy of mIBS025 vaccines prepared in a standard vaccine stabilizer or CMSS-AH was affected by the vaccination routes. The groups vaccinated via ED had better protective immunity than those vaccinated via DW.