• 제목/요약/키워드: Back Spin

검색결과 58건 처리시간 0.025초

탁구 포핸드 카운터 드라이브 동작의 운동학적 변인 및 지면 반력 분석 (Kinematic and Ground Reaction Force Analyses of the Forehand Counter Drive in Table Tennis)

  • 이용식;이종훈
    • 한국운동역학회지
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    • 제20권2호
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    • pp.155-165
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    • 2010
  • The purpose of this study was to analyze kinematic quantitative factors required of a forehand counter drive in table tennis through 3-D analysis. Four national table tennis players participated in this study. The mean of elapsed time for total drive motion was $1.009{\pm}0.23\;s$. At the phase of impact B1 was the fastest as 0.075 s. This may affect efficiency in the initial velocity and spin of the ball by making a powerful counter drive. The pattern of center of mass showed that it moved back and returned to where it was then moved forward. At the back swing, lower stance made wide base of support and a stronger and safer stance. It may help increasing the ball spin. Angle of the elbow was extended up to $110.75{\pm}1.25^{\circ}$ at the back swing and the angle decreased by $93.75{\pm}3.51^{\circ}$ at impact. Decreased rotation range of swinging arm increased linear velocity of racket-head and impulse on the ball. Eventually it led more spin to the ball and maximized the ball speed. Angle of knee joint decreased from ready position to back swing, then increased from the moment of the impact and decreased at the follow thorough. The velocity of racket-head was the fastest at impact of phase 2. Horizontal velocity was $7796.5{\pm}362\;mm/s$ and vertical velocity was $4589.4{\pm}298.4\;mm/s$ at the moment. It may help increase the speed and spin of the ball in a moment. The means of each ground reaction force result showed maximum at the back swing(E2) except A2. Vertical ground reaction force means suggest that all males and females showed maximum vertical power(E2), The maximum power of means was $499.7{\pm}38.8\;N$ for male players and $519.5{\pm}136.7\;N$ for female players.

이중 후방 응력 경화 모델을 이용한 주기 하중에서의 래쳐팅 거동 현상 연구 (Simulation of Ratcheting Behavior under Stress Controlled Cyclic Loading using Two-Back Stress Hardening Constitutive Relation)

  • 홍성인;황두순;윤수진
    • 소성∙가공
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    • 제17권1호
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    • pp.19-26
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    • 2008
  • In the present work, the ratcheting behavior under uniaxial cyclic loading is analyzed. A comparison between the published and the results from the present model is also included. In order to simulate the ratcheting behavior, Two-Back Stress model is proposed by combining the non-linear Armstrong-Frederick rule and the non-linear Phillips hardening rule based on kinematic hardening equation. It is shown that some ratcheting behaviors can be obtained by adjusting the control material parameters and various evolutions of the kinematic hardening parameter can be obtained by means of simple combination of hardening rules using simple rule of mixtures. The ultimate back stress is also derived for the present combined kinematic hardening models.

Comparative Evaluation of Mn(II) Framework Substitution in MnAPSO-34 and Mn-impregnated SAPO-34 Molecular Sieves Studied by Electron Spin Resonance and Electron Spin Echo Modulation Spectroscopy

  • Gernho Back;Kim, Yanghee;Cho, Young-Soo;Lee, Yong-Ill;Lee, Chul-Wee
    • 한국자기공명학회논문지
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    • 제6권1호
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    • pp.20-37
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    • 2002
  • MnAPSO-34 and Mn-impregnated SAPO-34(Mn-SAPO-34) sample were prepared with various manganese contents and studied by electron spin resonance(ESR) and electron spin echo modulation(ESEM). Electron spin echo modulation analysis of 0.07mo1 % Mn(relative to p) in MnAPSO-34 with adsorbed D$_{2}$O shows two deuteriums at 0.26 nm and two at 0.36 nm from Mn. This suggests that two waters hydrate an MnO$_{4}$ configuration with a D-O bond orientation for the waters as expect for a negatively charged site at low manganese content (0.1 mol%), the ESR spectra of MnAPSO-34 and MnH-SAPO-34 exhibit the same parameters(g 2.01 and A 89 G), but the spectra obtained from MnAPSO-34 samples are better resolved. The decomposition temperature of as-synthesized MnAPSO-34 were in the range of 200-600 $^{\circ}C$ of the morpholine which is 12 $^{\circ}C$ higher than that in as-synthesized MnH-SAPO-34. Infrared spectra showed that the position of a band at 3450 $cm^{-1}$ / shifted about 15 $cm^{-1}$ / toward higher energy in MnAPSO-34 versus MnH-SAPO-34. The modulation depth of the two-pulse ESE of MnAPSO-34 with adsorbed D$_{2}$O is deeper than that of MnH-SAPO-34 with adsorbed D$_{2}$O. Three-pulse ESEM of MnAPSO-34 and MnH-SAPO-34 with adsorbed deuterium oxide shows that the local environments of manganese in the hydrated samples are different, suggesting that Mn(II) is framework substituted in MnAPSO-34 since it obviously occupies an extraframework position in MnH-SAPO-34.

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Comparative Evaluation of Mn Substitution in a Framework Site in MnAPSO-34 and Mn-impregnated SAPO-34 Molecular Sieves Studied by Electron Spin Resonance and Electron Spin-Echo Modulation Spectroscopy

  • Gernho Back;Cho, Young-Soo
    • 한국자기공명학회:학술대회논문집
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    • 한국자기공명학회 2002년도 International Symposium on Magnetic Resonance
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    • pp.80-80
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    • 2002
  • MnPSO-34 and Mn-impregnated SAPO-34 (Mn-SAPO-34) sample were prepared with various manganese contents and studied by electron spin resonance (ESR) and electron spin-echo modulation (ESEM). Electron spin-echo modulation analysis of 0.07mol % Mn(relative to p) in MnAPSO-34 with adsorbed D$_2$O shows two deuteriums at 0.25 nm and two at 0.36 nm from Mn. This suggests that two waters hydrate an MnO4 configuration with a D-O bond orientation for the waters as expect for a negatively charged site at low manganese content (0.07 mol%), the ESR spectra of MnAPSO-34 and MnH-SAPO-34 exhibit the same parameters (g 2.02 and A 87 G), but the spectra obtained from MnAPSO-34 samples are better resolved. TGA of as-synthesized MnAPSO-34 shows that the decomposition temperature in the range 200-$600^{\circ}C$ of the morpholine is 12$^{\circ}C$ higher than that in as-synthesized MnH-SAPO-34. Infrared spectra shows that the position of a band at about 15 cm-1 toward higher energy in MnAPSO-34 versus MnH-SAPO-34. The modulation depth of the two-pulse ESE of MnAPSO-34 with absorbed D$_2$O is deeper than that of MnH-SAPO-34 with absorbed D$_2$O. Three-pulse ESEM of MnAPSO-34 and MnH-SAPO-34 with absorbed deuterium oxide shows that the local environments of manganese in the hydrated samples are different, suggesting that Mn(II) is framework substituted in MnAPSO-34 since it obviously occupies an extra-framework position in MnH-SAPO-34

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염료감응형 태양전지 투명전도성 막의 표면처리를 통한 계면 접촉 향상 및 재결합 방지 연구 (A Study on the Improvement of the Interface Contact and the Prevention of the Charge Recombination by the Surface Treatment of Transparent Conductive Oxide in Dye-sensitized Solar Cell)

  • 서현웅;홍지태;손민규;김진경;신인영;김희제
    • 전기학회논문지
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    • 제58권11호
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    • pp.2214-2218
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    • 2009
  • Dye-sensitized solar cell (DSC) has been considered as a possible alternative to current silicon based p-n junction photovoltaic devices due to its advantages of high efficiency, simple fabrication process and low production cost. Numerous researches for high efficient DSC in the various fields are under way even now. Among them, the compact layer, which prevents the back electron transfer between transparent conductive oxides and the redox electrolyte, is fabricated by various methods such as a ZnO dip-coating, $TiCl_4$ dip-coating, and Ti sputtering. In this study, we tried to fabricate the $TiO_2$ compact layer by the spin-coating method using aqueous $TiCl_4$ solution. The effect of the spin-coating method was checked as compared with conventional dip-coating method. As a result, DSC with a spin-coated compact layer had 33.4% and 6% better efficiency than standard DSC and DSC with a dip-coated compact layer.

A NOTE ON INVARIANT PSEUDOHOLOMORPHIC CURVES

  • Cho, Yong-Seung;Joe, Do-Sang
    • 대한수학회보
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    • 제38권2호
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    • pp.347-355
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    • 2001
  • Let ($X, \omega$) be a closed symplectic 4-manifold. Let a finite cyclic group G act semifreely, holomorphically on X as isometries with fixed point set $\Sigma$(may be empty) which is a 2-dimension submanifold. Then there is a smooth structure on the quotient X'=X/G such that the projection $\pi$:X$\rightarrow$X' is a Lipschitz map. Let L$\rightarrow$X be the Spin$^c$ -structure on X pulled back from a Spin$^c$-structure L'$\rightarrow$X' and b_2^$+(X')>1. If the Seiberg-Witten invariant SW(L')$\neq$0 of L' is non-zero and $L=E\bigotimesK^-1\bigotimesE$ then there is a G-invariant pseudo-holomorphic curve u:$C\rightarrowX$,/TEX> such that the image u(C) represents the fundamental class of the Poincare dual $c_1$(E). This is an equivariant version of the Taubes' Theorem.

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통계적 실험계획법을 이용한 SOG 평탄화 공정의 최적화 (Optimization of Spin-On-Glass Planarization Process Using Statistical Design of Experiments)

  • 임채영;박세근
    • 한국진공학회지
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    • 제1권1호
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    • pp.198-205
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    • 1992
  • 고집적 회로제작에 필수적인 평탄화 기술을 SOG를 이용하여 개발하였다. 1.5 micron double metal 기술의 공정변수들을 통계적 실험계획법을 적용하여 주요변수들을 찾 아내고 그들을 최적화하였다. 최적공적 조건은 SOG 도포 횟수는 2회, hot plate bake는 $300^{\circ}C$에서 충분히, 그리고 furnace curing은 $400^{\circ}C$ 이하에서 40분간 진행하는 것이었다.

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$Mn^{II}$ Location and Adsorbate Interactions in (M)MnH-SAPO-34 and (W)MnH-SAPO-34 studied by EPR and Electron Spin Echo Modulation Spectroscopies

  • Back, Gern-Ho;Kim, Yang-Hee;Cho, Young-Soo;Lee, Yong-Ill
    • 한국자기공명학회논문지
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    • 제6권2호
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    • pp.118-131
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    • 2002
  • Manganese-doped H-SAPO-34 samples were prepared by an ion-exchanged reaction between H-SAPO-34 and paramagnetic Mn(II) species in methanol media and characterized by ESR and Electron Spin-Echo Modulation(ESEM) studies. In the hydrated (W)MnH-SAPO-34 measured in water, the Mn(II) ion was octahedrally coordinated with four framework oxygens and two water molecules at a displaced site IV of the eight membered ring window in the ellipsoidal cavity, while the Mn(II) ion was octahedrally coordinated to three framework oxygens and three water molecules at a displaced site I' of the six membered ring window in the ellipsoidal cavity in hydrated(M)MnH-SAPO-34 measured in methanol. The similar result was found in the experiments with methanol adsorbents except ethanol.

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