• 제목/요약/키워드: External Effect

검색결과 3,428건 처리시간 0.028초

집중방식이 이중과제 수행에 미치는 영향 (The Effect of Attentional Focus on the Performance of Dual Task)

  • 노정석;이충휘;조상현;전혜선;권혁철;김택훈
    • 한국전문물리치료학회지
    • /
    • 제15권2호
    • /
    • pp.11-19
    • /
    • 2008
  • Studies of attentional focus effects, have shown that the performer's attentional focus plays an important role in the performance and learning of motor tasks. We examined the influence of attentional focus on the performance of dual tasks (a postural task and a suprapostural task) and used electromyography (EMG) to examine whether the differences between external and internal focus were also manifest at the neuromuscular level. The subjects (n=40) stood on a balance board (postural task) and held a bar horizontally (suprapostural task). All of the subjects performed under different attentional focus conditions: external (balancer on balance board) or internal (feet) focus on the postural task, and external (balancer on bar) or internal (hand) focus on the suprapostural task. The mean displacement velocity of the bar and the percent reference voluntary contraction (%RVC) of the biceps brachii were reduced when the subjects adopted an external focus on the suprapostural task (p<.05). In addition, the mean displacement velocity of the balance board and %RVC of the tibialis anterior were reduced when the subjects adopted an external focus on the postural task (p<.05). When the subjects adopted an external focus on the suprapostural task, the mean displacement velocity of the balance board and %RVC of the tibialis anterior were also reduced (p<.05). When the subjects' attentional focus was on the postural task, there were no differences in the mean displacement and %RVC of the biceps brachii between attentional focuses. The performance of each task was enhanced when subjects focused on the respective task. The suprapostural task goals had a stronger influence on postural control than vice versa. These results reflect the propensity of the motor system to optimize control processes based on the environmental outcome, or movement effect, that the performer wants to achieve.

  • PDF

UHFPD측정시스템을 이용한 GISPD측정 (GISPD Measurement Using UHFPD Measurement System)

  • 최재구;이상화;김광화
    • 대한전기학회:학술대회논문집
    • /
    • 대한전기학회 2004년도 하계학술대회 논문집 C
    • /
    • pp.1857-1859
    • /
    • 2004
  • It is widely known that the ultra high frequency (UHF) method that detects the electromagnetic wave of the PD pulses in the gas insulated space is one of the most competitive methods for its high sensitivity. From the above point of view, this paper describes the noise suppression methods and the PD measurement results of the in-service substation by the developed UHF PD measurement system which consists of the external UHF coupler, the UWB LNA and the digital storage oscilloscope. As results, it was found that the effect of the noise suppression methods were verified and that the developed external UHF coupler showed a better detection sensitivity than a conventional external coupler.

  • PDF

Design of Tissue-Transfer Container Using Thermoelectric Element Module

  • Park, Yong Pil;Cheon, Min-Woo
    • Transactions on Electrical and Electronic Materials
    • /
    • 제18권2호
    • /
    • pp.66-69
    • /
    • 2017
  • The internal temperature of human-tissue transfers must be steadily maintained regardless of the external environmental changes. An ice pack and dry ice are the coolants for the transfer containers for which heat-insulating materials such as EPP (expended polypeopylene and EPS (expended polystrene) are used; however, changes of the external temperature/pressure and the melting of the coolants that is due to a long carriage result in changes of the internal temperature, and this makes it difficult to maintain the temperature. Accordingly, the thermoelectric element was used to design/manufacture a transfer container to maintain the internal temperature regardless of the external environmental changes. As a result of the measurement of the changes of the internal temperatures of the manufactured thermoelectric-element container and the EPS container over time, the internal temperature of the EPS container was increased, whereas the internal temperature of the thermoelectric-element container was maintained. The temperature of the distilled water that was poured into the containers indicated a pattern identical to that of the internal temperature.

연삭숫돌 주축 및 공작물 회전체 진동을 고려한 원통 연삭 가공의 동특성 해석 (Dynamic Analysis of External Cylindrical Grinding Considering Spindle and Workpiece Vibrations)

  • 최상현;김덕현;안유민
    • 한국정밀공학회지
    • /
    • 제17권6호
    • /
    • pp.192-198
    • /
    • 2000
  • This paper presents multi degree analysis of self-exited vibration of grinding system including spindle and workpiece rotational effect. The governing equations are derived by applying the finite element method to structure of spindle and workpiece rotor and by estimating the grinding force. Vibration analysis is carried out for external cylindrical plunge grinding. Displacement of workpiece and grinding force is simulated with machining time. Using this model, effects of characteristics of spindle bearing and major grinding conditions on chatter growth rate are predicted. Some of results are compared with those of other previous model and show good agreements.

  • PDF

외부 강선 보강의 체계적 분류 연구 (A Study on Systematic Classification for External Prestressing Method)

  • 한만엽;박영훈
    • 한국콘크리트학회:학술대회논문집
    • /
    • 한국콘크리트학회 2002년도 봄 학술발표회 논문집
    • /
    • pp.411-416
    • /
    • 2002
  • With a rapid industrialization, repair and strengthening methods for a damaged bridges are raised a head in face of safety and reduction of physical distribution costs of bridges. Above all, external prestressing method has the high adaptability for concrete structures and the reliable effect of strengthening. Innovative ideas for bridges strengthening were considered along with established methods. That methods are identified, described. However there is not a systematic and categorized manual for external prestressing method. This study will provide a systematic and reliable manual with investigating the arrangement shape of cable and characteristics of brackets. And the key result of this study is an extensive compilation, which can be used by practicing engineers, of the most effective techniques for strengthening existing bridges.

  • PDF

Mathematical Modeling of the Effect of External Radiative Heating on Heat and Mass Transfer Between A Semi-transparent Diesel Fuel Droplet and Quiescent Air

  • Woo In-Sung;Choi Sung-Eul;Stamatov Venelin
    • International Journal of Safety
    • /
    • 제3권1호
    • /
    • pp.20-26
    • /
    • 2004
  • The system considered in this model consists of a single, semi- transparent, diesel fuel droplet, which is immobile in the heating area and surrounded by a quiescent air. A uniform external radiation field surrounds the droplet. Results from mathematical simulation suggest that because of the higher surface temperature, the external radiative heating of the droplet can promote an earlier ignition of the fuel vapour/air mixture. The radiative heating of the droplet increases the mass transfer from the droplet to the surrounding gas-phase, thus, decreasing the heterogeneity of the fuel droplet/air system.

Buckling assessment of dented truncated cones under external pressure

  • Ghazijahani, Tohid Ghanbari;Showkati, Hossein;Jiao, Hui
    • Advances in Computational Design
    • /
    • 제1권4호
    • /
    • pp.345-356
    • /
    • 2016
  • Notwithstanding a considerable body of references in the literature on the buckling response of conical shell structures, it seems imperative to provide further insight on the buckling response of locally imperfect steel cones. This paper contains different simulations including non-linear FE analysis and discusses the influence of dent imperfection on the buckling load of these structures subject to external pressure. Data of the present work are evaluated against available experimental results, codes and recommendations and the effect of the local damages is exhaustively set forth. It is also found that the employed FE program can reliably predict the structural response of locally damaged conical shells.

Block of HERG Channels Expressed in Xenopus Oocytes by External $H^+$

  • Jo, Su-Hyun;Kim, Injune;Yung E. Earm;Lee, Chin-Ok;Ho, Won-Kyung
    • 한국생물물리학회:학술대회논문집
    • /
    • 한국생물물리학회 1998년도 학술발표회
    • /
    • pp.36-36
    • /
    • 1998
  • We reported previously that HERG current, molecular equivalent of I$_{kr}$, expressed in Xenopus oocytes is blocked by external $Ca^{2+}$ and $Mg^{2+}$. In the present study, we have investigated the effect of external H+ on HERG current (I$_{HERG}$) using the two microelectrode voltage clamp.(omitted)ted)

  • PDF

엔진 연결봉 베어링의 운동 궤적 해석 (Analysis of Journal Locus in a Connecting Rod Bearing)

  • 조명래;정진영;한동철
    • 한국윤활학회:학술대회논문집
    • /
    • 한국윤활학회 1997년도 제25회 춘계학술대회
    • /
    • pp.183-189
    • /
    • 1997
  • This paper presents the motion of dynamically loaded journal in the connecting rod bearing of reciprocating internal combustion engine. Journal motions in engine bearings have been composed of two components, which was rotational and translational motion. Early study of journal locus in engine bearing had been performed on each motion. This paper has been considered two motions simultaneously. Reynolds equation including the squeeze effect has been analyzed using the ADI method, and real engine bearing and crankshaft system has been considered to calculate the cyclic external force. The equations of journal motion have been derived and then the numerical integration of these equations performed by 4th order Runge-Kutta method. This paper gives various journal orbits in connecting rod bearing depending on cyclic external forces, rotating speeds, and bearing parameters.

  • PDF

국내원전 단열재 설계특성에 따른 외벽냉각 효과검증 실험 (Experiment on Coolability through External Reactor Vessel Cooling according to RPV Insulation Design)

  • 강경호;박래준;김상백
    • 대한기계학회:학술대회논문집
    • /
    • 대한기계학회 2003년도 춘계학술대회
    • /
    • pp.1578-1583
    • /
    • 2003
  • LAVA-ERVC experiments have been performed to investigate the effect of insulation design features on the coolability in case of the external reactor vessel cooling (ERVC). All the 4 tests have been performed using Alumina iron thermite melt as a corium simulant. Due to the limited steam venting through the insulation, steam binding occurred inside the annulus in the KSNP case simulation. On the contrary, in the tests which were performed for simulating the APR1400 insulation design, sufficient water ingression and steam venting through the insulation lead to effective cool down of the vessel characterized by nucleate boiling. It could be found from the experimental results that modification of the insulation design allowing sufficient ventilation could increase the positive effects of the external reactor vessel cooling.

  • PDF