• Title/Summary/Keyword: Contact Stability

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Effects of Emphasized Initial Contact Auditory Feedback Gait Training on Balance and Gait in Stroke Patients (뇌졸중 환자의 초기 접지기를 강조한 청각적-피드백 보행훈련이 균형능력과 보행기능에 미치는 영향)

  • Kim, Jung-Doo;Cha, Yong-Jun;Youn, Hye-Jin
    • Journal of the Korean Society of Physical Medicine
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    • v.10 no.4
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    • pp.49-57
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    • 2015
  • PURPOSE: This study aimed to investigate the effect of emphasized initial contact gait training on balance and gait ability in hemiplegia patients. METHODS: Twenty-four hemiplegic patients were randomly allocated to an experimental group or control group. All participants received 30-min neurodevelopmental treatment. Furthermore, the experimental group received initial contact-emphasized auditory feedback gait training, whereas the control group received gait training without auditory feedback. The intervention was performed 3 times per week, 20 min per each time, for a total of 6 weeks. Balance was assessed using the center of pressure path length, center of pressure velocity, and limitation of stability path length, whereas gait ability was assessed using the 10-m walking test and functional gait assessment. RESULTS: In both groups, center of pressure path length and center of pressure velocity significantly decreased after training. Compared to the control group, the experimental group showed a 10% significant improvement (p<.05). In the limitation of stability path length of both sides, the experimental group showed a significant increase compared to that before intervention. Compared to the control group, the experimental group showed a 7% significant improvement in results of the 10-m walking test and functional gait assessment (p<.05). CONCLUSION: Emphasized Initial contact gait training is considered an effective treatment for improving gait ability and balance ability in stroke patients.

The study on a mobile robot for going up and down stairs in nuclear facilities (원전시설용 이동로보트의 계단승하강에 관한 연구)

  • 김병수;김창회;황석용;김승호;이종민
    • 제어로봇시스템학회:학술대회논문집
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    • 1990.10a
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    • pp.731-735
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    • 1990
  • The mobile robot, named as KAEROT, is designed to go up and down stairs in nuclear facilities. To get a proper stable motion, kinematic modeling and analysis are seriously considered and new climbing algorithm is proposed focused on the stability. A couple of small wheels of one planetary wheel have to contact the surface ol stairs all the time to give the guarantee for stability and safety. To confirm the validity of the proposed algorithm, simulation is carried out. The results make evident of feasibility for the algorithm.

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Formation of Ohmic Contact in P-Type CdTe Using Cu2 Te Electrode and Its Effect on the Photovoltaic Properties of CdTe Solar Cells (Cu2Te 배면 전극을 이용한 p-type CdTe 태양전지의 ohmic contact 형성 및 CdTe 태양전지의 광전압 특성)

  • Kim, Ki-Hwan;Yun, Jae-Ho;Lee, Doo-Youl;Ahn, Byung-Tae
    • Korean Journal of Materials Research
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    • v.12 no.12
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    • pp.918-923
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    • 2002
  • In this work, CdTe films were deposited on CdS/ITO/glass substrate by a close spaced sublimation (CSS) method. A $Cu_2$Te layer was deposited on the CdTe film by evaporating $Cu_2$Te powder. Then the samples were annealed for p+ ohmic contact. TEM and XRD analysis showed that $CdTe/Cu_2$Te interface exhibited different forms with various annealing temperature. A good p+ ohmic contact was achieved when the annealing temperature was between $180^{\circ}C$ to $200^{\circ}C$. Best cell efficiency of 12.34% was obtained when post annealing temperature was $200^{\circ}C$ for 5 min. Thermal stress test of the CdS/CdTe cells with carbon back contact showed that the $Cu_2$Te contact was stable at $50^{\circ}C$ in $N_2$ and was slowly degraded at $100^{\circ}C$ in $N_2$. In comparison to the conventional carbon contact, the $Cu_2$Te contact showed a better thermal stability.

Analysis of Suspension State Matrix to Improve L/UL Performance (로드/언로드 성능향상을 위한 서스펜션 상태행렬의 해석)

  • Kim, Ki-Hoon;Lee, Young-Hyun;Park, Kyung-Su;Park, No-Cheol;Park, Young-Pil
    • Proceedings of the Korean Society for Noise and Vibration Engineering Conference
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    • 2007.11a
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    • pp.1272-1275
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    • 2007
  • The HDD (hard disk drive) using Load/Unload (L/UL) technology includes the benefits which are increased areal density, reduced power consumption and improved shock resistance than those of contact-start-stop (CSS). Dynamic L/UL has been widely used in portable hard disk drive and will become the key technology for developing the small form factor hard disk drive. Main design objectives of the L/UL mechanisms are no slider-disk contact or no media damage even with contact during L/UL, and a smooth and short load and unload process. In this paper, we focus on state matrix, pitch static attitude (PSA), roll static attitude (RSA), loading/unloading contour (LC/ULC), impact force and contact. Stability of slider is mainly determined by PSA and RSA. State matrix by PSA and RSA is also important indicator. Therefore we analyze state matrix of SFF HDD suspension through the LC/ULC.

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Design and Experiment investigation of disk bump to improve unload performance in HDD (HDD에서 언로드 성능향상을 위한 디스크 범프의 설계 및 실험 연구)

  • Lee, Hyung-Jun;Lee, Yong-Hyun;Park, Gyeong-Su;Park, No-Cheol;Park, Young-Pil
    • Proceedings of the Korean Society for Noise and Vibration Engineering Conference
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    • 2007.05a
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    • pp.833-836
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    • 2007
  • Load/Unload technology has more benefits than the conventional CSS technology. However, it remains unsolved technical problem on the unloading process. While the slider climbs up the ramp at the outer edge of the disk, the possibility of the slider-disk contact by lift-off force and rebound of the slider increases. This paper focuses on no slider-disk contact. To prevent the slider-disk contact, we apply the disk bump on disk outer edge proceeding unload. Firstly, in the simulation, the bump dimension is determined by changing bump design parameters. Secondly, dynamic stability of slider have to be checked on disk bump before unload analysis, and unload analysis is performed by applying stable bump shapes to unload simulation. Thirdly, we select optimal bump shape to improve unload performance by unload analysis. Finally, in the experiment, the disk bump is mechanically manufactured by pressing disk surface using diamond tip. That is variously processed by changing pressing pressure. After confirming bump shape by nano-scanner, proper bump shape is applied to real experimental unload process. Through this investigation, we propose the optimal bump design to prevent the slider-disk contact, and then we can realize improved unloading performance.

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Analysis of the DC Resistance of the Butt Joint using the Random Contact Patterns of Strands

  • Lee, Ho-Jin;Lee, Sang-Il;Lee, Bong-Sang
    • Progress in Superconductivity and Cryogenics
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    • v.6 no.4
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    • pp.17-21
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    • 2004
  • The butt joint was verified to satisfy the thermal stability of the ITER magnet system through the ITER CS model coil test. Since the contact area in the butt joint is limited to the cross section of the cable, it is necessary to analyze and control the joining parameters precisely for improving the DC resistance. It is difficult to simulate the cables, which are composed of a lot of strands, as three-dimensional models using the commercial code. The random numbers were used to simulate many kinds of contact patterns of the strands on the bonding surface for calculating the bonding area and the DC resistance of the butt joint. The calculated DC resistance decreases with an increase of cable filling factor in terminal. The calculated DC resistance of a 0.9 cable filling factor is about 0.48 n-Ohm, which is about one-tenth of that in the CS model coil test when not considering the electrical contact resistance. From this difference, the electrical contact resistance between the strands and copper sheet was calculated.

Analysis on Fitting Characteristics of a Metal-Sealing Pipe of the Hydrogen Fuel Tank for FCEV (FCEV용 고압연료탱크 메탈씰링 파이프의 체결특성 해석)

  • Lee, J.M.;Jeong, J.H.;Chon, M.S.;Lee, H.W.
    • Transactions of Materials Processing
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    • v.27 no.1
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    • pp.54-59
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    • 2018
  • In connecting parts of a hydrogen fuel cell vehicle, since the rubber ring is permeable to hydrogen, it is necessary to use a metal sealing structure which ensures leakage stability. Finite element analysis was performed to verify the fitting characteristics of the metal sealing structure, which is used to connect the pipe to a high pressure hydrogen FCEV tank. Deformation shape, contact distance and axial load were compared experimentally and these values were in agreement with each other. In the contact surface, between the pipe and the fitting body, the stress at the edge of the contact surface was higher than the center point, which was considered to be a good characteristic in view point of the leakage. The location of the contact points has almost no change in the upper part of the fitting, but that of the lower parts move downward as the fastening amount increases. The contact pressure at the lower part is maintained at the same constant level.

A Case of Occupational Allergic Contact Dermatitis Caused by Mortar (모르타르로 인한 직업성 알레르기성 접촉성 피부염 치험 1례)

  • Eom, Ye-Jin;Hong, Chul-Hee
    • The Journal of Korean Medicine Ophthalmology and Otolaryngology and Dermatology
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    • v.27 no.4
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    • pp.209-220
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    • 2014
  • Objectives : The purpose of this study is to report the effect of Korean medicine treatment on occupational allergic contact dermatitis caused by mortar. Methods : The patient treated by herbal medicine, acupuncture, pharmacopuncture and external therapy. The progress is evaluated by Numerical Rating Scale(NRS) and Dermatology Life Quality Index(DLQI). Results : NRS and DLQI score were significantly decreased as a result of Korean medicine treatment. Conclusions : Korean medicine treatment should be effective for the occupational allergic contact dermatitis caused by mortar. More studies are needed to confirm stability of these treatment.

Microstructure and Characteristics of Ag-SnO2-Bi2O3 Contact Materials by Powder Compaction (분말성형법으로 제조된 Ag-SnO2-Bi2O3 접점소재의 미세조직 및 특성)

  • Lee, Jin Kyu
    • Journal of Powder Materials
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    • v.29 no.1
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    • pp.41-46
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    • 2022
  • In this study, we report the microstructure and characteristics of Ag-SnO2-Bi2O3 contact materials using a controlled milling process with a subsequent compaction process. Using magnetic pulsed compaction (MPC), the milled Ag-SnO2-Bi2O3 powders have been consolidated into bulk samples. The effects of the compaction conditions on the microstructure and characteristics have been investigated in detail. The nanoscale SnO2 phase and microscale Bi2O3 phase are well-distributed homogeneously in the Ag matrix after the consolidation process. The successful consolidation of Ag-SnO2-Bi2O3 contact materials was achieved by an MPC process with subsequent atmospheric sintering, after which the hardness and electrical conductivity of the Ag-SnO2-Bi2O3 contact materials were found to be 62-75 HV and 52-63% IACS, respectively, which is related to the interfacial stability between the Ag matrix, the SnO2 phase, and the Bi2O3 phase.

The Effect on Launching Stability Due to the Initial Missile Detent Force (유도탄의 초기 구속력이 발사안정에 미치는 영향)

  • 심우전;임범수;이우진
    • Journal of the Korean Society for Precision Engineering
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    • v.14 no.4
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    • pp.22-29
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    • 1997
  • This paper presents results on dynamic analysis of the missile initial motion arising from the missile detent force. Using ADAMS (Automatic Dynamic Analysis of Mechanical Syatem) software, a non- linear46-DOF (Degree of Freedom) model is developed for the launcher system including missile and lunch tube contact problem. From the dynamic analysis, it is found that initial angular velocity of the missile incre- ases when the missile detent force increases and also when rocket exhaust plume is taken into account. To achieve the missile launching stability, it needs to reduce the missile initial detent force and exhaust plume area of the lancher. Results of the dynamic analysis on the system natural frequency agree well with those obtained from experimental modal tests. The overall results suggest that the proposed method is a useful tool for prediction of initial missile stability as well as design of the missile launcher system.

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