메뉴 건너뛰기




Volumn 17, Issue 4, 2009, Pages

Shear response of the Σ11, 〈1 1 0〉{1 3 1} symmetric tilt grain boundary studied by molecular dynamics

Author keywords

[No Author keywords available]

Indexed keywords

COUPLED SHEAR DEFORMATION; COUPLING FACTOR; DEFORMATION BEHAVIOR; EMBEDDED-ATOM METHOD; INTERATOMIC POTENTIAL; PLASTIC STRAIN; PURE SHEAR; SHEAR DIRECTION; SHEAR RESPONSE; SIMULATED RESULTS; TILT GRAIN BOUNDARY;

EID: 67650727935     PISSN: 09650393     EISSN: 1361651X     Source Type: Journal    
DOI: 10.1088/0965-0393/17/4/045008     Document Type: Article
Times cited : (33)

References (59)
  • 2
    • 34249944526 scopus 로고    scopus 로고
    • Toward a quantitative understanding of mechanical behavior of nanocrystalline metals
    • Dao M, Lu L, Asaro R J, De Hosson J T M and Ma E 2007 Toward a quantitative understanding of mechanical behavior of nanocrystalline metals Acta Mater. 55 4041
    • (2007) Acta Mater. , vol.55 , Issue.12 , pp. 4041
    • Dao, M.1    Lu, L.2    Asaro, R.J.3    De Hosson, J.T.M.4    Ma, E.5
  • 3
    • 24044554945 scopus 로고
    • Observations of creep of the the grain boundary in high purity aluminum
    • Chang H C and Grant N J 1952 Observations of creep of the the grain boundary in high purity aluminum Trans. AIME 194 619
    • (1952) Trans. AIME , vol.194 , pp. 619
    • Chang, H.C.1    Grant, N.J.2
  • 4
    • 0008776462 scopus 로고
    • Grain boundary shear in aluminum
    • Weinberg F 1958 Grain boundary shear in aluminum Trans. AIME 212 808
    • (1958) Trans. AIME , vol.212 , pp. 808
    • Weinberg, F.1
  • 5
    • 0000920234 scopus 로고
    • Grain boundary sliding, migration and deformation in high-purity aluminum
    • Walter J L and Cline H E 1968 Grain boundary sliding, migration and deformation in high-purity aluminum Trans. AIME 242 1823
    • (1968) Trans. AIME , vol.242 , pp. 1823
    • Walter, J.L.1    Cline, H.E.2
  • 7
    • 0000860083 scopus 로고
    • Boundary defects and atomistic aspects of boundary sliding and diffusion creep
    • Ashby M F 1972 Boundary defects and atomistic aspects of boundary sliding and diffusion creep Surf. Sci. 31 498
    • (1972) Surf. Sci. , vol.31 , pp. 498
    • Ashby, M.F.1
  • 9
    • 0017907396 scopus 로고
    • On the role of grain boundary dislocations in high temperature creep
    • Pond R C, Smith D A and Southerden P W J 1978 On the role of grain boundary dislocations in high temperature creep Phil. Mag. A 37 27
    • (1978) Phil. Mag. , vol.37 , Issue.1 , pp. 27
    • Pond, R.C.1    Smith, D.A.2    Southerden, P.W.J.3
  • 10
    • 0020090594 scopus 로고
    • Step heights associated with grain boundary dislocations in cubic crystals
    • King A H 1982 Step heights associated with grain boundary dislocations in cubic crystals Acta Metall. 30 419
    • (1982) Acta Metall. , vol.30 , Issue.2 , pp. 419
    • King, A.H.1
  • 11
    • 0028526998 scopus 로고
    • Dislocations, steps and disconnections at interfaces
    • Hirth J P 1994 Dislocations, steps and disconnections at interfaces J. Phys. Chem. Solids 55 985
    • (1994) J. Phys. Chem. Solids , vol.55 , Issue.10 , pp. 985
    • Hirth, J.P.1
  • 12
    • 0030408955 scopus 로고    scopus 로고
    • Steps, dislocations and disconnections as interface defects relating to structure and phase transformations
    • Hirth J P and Pond R C 1996 Steps, dislocations and disconnections as interface defects relating to structure and phase transformations Acta Mater. 44 4749
    • (1996) Acta Mater. , vol.44 , Issue.12 , pp. 4749
    • Hirth, J.P.1    Pond, R.C.2
  • 13
    • 0041919523 scopus 로고    scopus 로고
    • Special interfaces: Military transformations
    • Pond R C and Celotto S 2003 Special interfaces: military transformations Int. Mater. Rev. 48 225
    • (2003) Int. Mater. Rev. , vol.48 , Issue.4 , pp. 225
    • Pond, R.C.1    Celotto, S.2
  • 14
    • 0000067042 scopus 로고
    • Crystal dislocation: Elementary concepts and definitions
    • Frank F C 1951 Crystal dislocation: elementary concepts and definitions Phil. Mag. 42 809
    • (1951) Phil. Mag. , vol.42 , pp. 809
    • Frank, F.C.1
  • 16
    • 0022011222 scopus 로고
    • Grain boundary sliding-migration of aluminium 〈110〉Σ11(1 1 3) symmetric tilt coincidence grain boundary and its interpretation based on the motion of perfect DSC dislocations
    • Fukutomi H and Kamijo T 1985 Grain boundary sliding-migration of aluminium 〈110〉Σ11(1 1 3) symmetric tilt coincidence grain boundary and its interpretation based on the motion of perfect DSC dislocations Scr. Metall. 19 195
    • (1985) Scr. Metall. , vol.19 , Issue.2 , pp. 195
    • Fukutomi, H.1    Kamijo, T.2
  • 17
    • 0031200467 scopus 로고    scopus 로고
    • On the contribution of extrinsic grain boundary dislocations to grain boundary sliding in bicrystals
    • Sheikh-Ali A D 1997 On the contribution of extrinsic grain boundary dislocations to grain boundary sliding in bicrystals Acta Mater. 45 3109
    • (1997) Acta Mater. , vol.45 , Issue.8 , pp. 3109
    • Sheikh-Ali, A.D.1
  • 18
    • 0026187128 scopus 로고
    • Sliding behavior of coincidence grain boundaries deviating from ideal symmetric tilt relationship
    • Fukutomi H, Iseki T, Endo T and Kamijo T 1991 Sliding behavior of coincidence grain boundaries deviating from ideal symmetric tilt relationship Acta Metall. Mater. 39 1445
    • (1991) Acta Metall. Mater. , vol.39 , Issue.7 , pp. 1445
    • Fukutomi, H.1    Iseki, T.2    Endo, T.3    Kamijo, T.4
  • 19
    • 0032048209 scopus 로고    scopus 로고
    • Sliding behavior of symmetric tilt near boundary in zinc bicrystals
    • Sheikh-Ali A D and Szpunar J A 1998 Sliding behavior of symmetric tilt near boundary in zinc bicrystals Mater. Sci. Eng. A 245 49
    • (1998) Mater. Sci. Eng. , vol.245 , Issue.1 , pp. 49
    • Sheikh-Ali, A.D.1    Szpunar, J.A.2
  • 20
    • 33745640516 scopus 로고    scopus 로고
    • Duality of dislocation content of grain boundaries
    • Cahn J W, Mishin Y and Suzuki A 2006 Duality of dislocation content of grain boundaries Phil. Mag. 86 3965
    • (2006) Phil. Mag. , vol.86 , Issue.25-26 , pp. 3965
    • Cahn, J.W.1    Mishin, Y.2    Suzuki, A.3
  • 21
    • 33750008736 scopus 로고    scopus 로고
    • Coupling grain boundary motion to shear deformation
    • Cahn J W, Mishin Y and Suzuki A 2006 Coupling grain boundary motion to shear deformation Acta Mater. 54 4953
    • (2006) Acta Mater. , vol.54 , Issue.19 , pp. 4953
    • Cahn, J.W.1    Mishin, Y.2    Suzuki, A.3
  • 22
    • 30944440750 scopus 로고    scopus 로고
    • Atomistic sliding mechanisms of the Σ = 5 symmetric tilt grain boundary in bcc iron
    • Hyde B, Farkas D and Caturla M J 2005 Atomistic sliding mechanisms of the Σ = 5 symmetric tilt grain boundary in bcc iron Phil. Mag. 85 3795
    • (2005) Phil. Mag. , vol.85 , Issue.32 , pp. 3795
    • Hyde, B.1    Farkas, D.2    Caturla, M.J.3
  • 23
    • 0018999889 scopus 로고
    • On the mechanisms of grain boundary migration
    • Rae C M F and Smith D A 1980 On the mechanisms of grain boundary migration Phil. Mag. A 41 477
    • (1980) Phil. Mag. , vol.41 , Issue.4 , pp. 477
    • Rae, C.M.F.1    Smith, D.A.2
  • 24
    • 0020172026 scopus 로고
    • Computer molecular-dynamics studies of grain-boundary structures: I. Observations of coupled sliding and migration in a three-dimensional simulation
    • Bishop G H Jr, Harrison R J, Kwok T and Yip S 1982 Computer molecular-dynamics studies of grain-boundary structures: I. Observations of coupled sliding and migration in a three-dimensional simulation J. Appl. Phys. 53 5596
    • (1982) J. Appl. Phys. , vol.53 , Issue.8 , pp. 5596
    • Bishop, G.H.1    Harrison, R.J.2    Kwok, T.3    Yip, S.4
  • 25
    • 0020169377 scopus 로고
    • Computer molecular-dynamics studies of grain-boundary structures: II. Migration, sliding and annihilation in a two-dimensional solid
    • Bishop G H Jr, Harrison R J, Kwok T and Yip S 1982 Computer molecular-dynamics studies of grain-boundary structures: II. Migration, sliding and annihilation in a two-dimensional solid J. Appl. Phys. 53 5609
    • (1982) J. Appl. Phys. , vol.53 , Issue.8 , pp. 5609
    • Bishop, G.H.1    Harrison, R.J.2    Kwok, T.3    Yip, S.4
  • 26
    • 0024739361 scopus 로고
    • Grain boundary kinetics: I. in situ observations of coupled grain boundary dislocation motion, crystal translation and boundary displacement
    • Babcock S E and Balluffi R W 1989 Grain boundary kinetics: I. In situ observations of coupled grain boundary dislocation motion, crystal translation and boundary displacement Acta Metall. 37 2357
    • (1989) Acta Metall. , vol.37 , Issue.9 , pp. 2357
    • Babcock, S.E.1    Balluffi, R.W.2
  • 27
    • 4544344914 scopus 로고    scopus 로고
    • Direct observation of deformation-induced grain growth during nanoindentation of ultrafine-grained Al at room temperature
    • Jin M, Minor A M, Stach E A and Morris J W 2004 Direct observation of deformation-induced grain growth during nanoindentation of ultrafine-grained Al at room temperature Acta Mater. 52 5381
    • (2004) Acta Mater. , vol.52 , Issue.18 , pp. 5381
    • Jin, M.1    Minor, A.M.2    Stach, E.A.3    Morris, J.W.4
  • 28
    • 11144236598 scopus 로고    scopus 로고
    • The influence of time, temperature and grain size on indentation creep in high-purity nanocrystalline and ultrafine grain copper
    • Zhang K, Weertman J R and Eastman J A 2004 The influence of time, temperature and grain size on indentation creep in high-purity nanocrystalline and ultrafine grain copper Appl. Phys. Lett. 85 5194
    • (2004) Appl. Phys. Lett. , vol.85 , pp. 5194
    • Zhang, K.1    Weertman, J.R.2    Eastman, J.A.3
  • 29
    • 23944457361 scopus 로고    scopus 로고
    • Rapid stress-driven grain coarsening in nanocrystalline Cu at ambient and cryogenic temperatures
    • Zhang K, Weertman J R and Eastman J A 2005 Rapid stress-driven grain coarsening in nanocrystalline Cu at ambient and cryogenic temperatures Appl. Phys. Lett. 87 061921
    • (2005) Appl. Phys. Lett. , vol.87 , Issue.6 , pp. 061921
    • Zhang, K.1    Weertman, J.R.2    Eastman, J.A.3
  • 30
    • 33645961888 scopus 로고    scopus 로고
    • Stress-assisted discontinuous grain growth and its effect on the deformation behavior of nanocrystalline aluminum thin films
    • Gianola D S, Van Petegem S, Legros M, Brandstetter S, Van Swygenhoven H and Hemker K J 2006 Stress-assisted discontinuous grain growth and its effect on the deformation behavior of nanocrystalline aluminum thin films Acta Mater. 54 2253
    • (2006) Acta Mater. , vol.54 , Issue.8 , pp. 2253
    • Gianola, D.S.1    Van Petegem, S.2    Legros, M.3    Brandstetter, S.4    Van Swygenhoven, H.5    Hemker, K.J.6
  • 31
    • 33846272092 scopus 로고    scopus 로고
    • Strain-induced coarsening in nano-grained films
    • Jin M, Minor A M and Morris J W 2007 Strain-induced coarsening in nano-grained films Thin Solid Films 515 3202
    • (2007) Thin Solid Films , vol.515 , Issue.6 , pp. 3202
    • Jin, M.1    Minor, A.M.2    Morris, J.W.3
  • 32
    • 47349089088 scopus 로고    scopus 로고
    • In situ TEM observations of fast grain-boundary motion in stressed nanocrystalline aluminum films
    • Legros M, Gianola D S and Hemker K J 2008 In situ TEM observations of fast grain-boundary motion in stressed nanocrystalline aluminum films Acta Mater. 56 3380
    • (2008) Acta Mater. , vol.56 , Issue.14 , pp. 3380
    • Legros, M.1    Gianola, D.S.2    Hemker, K.J.3
  • 33
    • 38049089299 scopus 로고    scopus 로고
    • Deformation-induced grain rotation and growth in nanocrystalline Ni
    • Wang Y B, Li B Q, Sui M L and Mao S X 2008 Deformation-induced grain rotation and growth in nanocrystalline Ni Appl. Phys. Lett. 92 011903
    • (2008) Appl. Phys. Lett. , vol.92 , Issue.1 , pp. 011903
    • Wang, Y.B.1    Li, B.Q.2    Sui, M.L.3    Mao, S.X.4
  • 34
    • 33846376270 scopus 로고    scopus 로고
    • Grain boundary migration during room temperature deformation of nanocrystalline Ni
    • Farkas D, Froseth A and Van Swygenhoven H 2006 Grain boundary migration during room temperature deformation of nanocrystalline Ni Scr. Mater. 55 695
    • (2006) Scr. Mater. , vol.55 , Issue.8 , pp. 695
    • Farkas, D.1    Froseth, A.2    Van Swygenhoven, H.3
  • 35
    • 14644414229 scopus 로고    scopus 로고
    • Mechanical behavior of Σ tilt grain boundaries in nanoscale Cu and Al: A quasicontinuum study
    • Sansoz F and Molinari J F 2005 Mechanical behavior of Σ tilt grain boundaries in nanoscale Cu and Al: A quasicontinuum study Acta Mater. 53 1931
    • (2005) Acta Mater. , vol.53 , Issue.7 , pp. 1931
    • Sansoz, F.1    Molinari, J.F.2
  • 36
    • 33746221382 scopus 로고    scopus 로고
    • Increased strain rate sensitivity due to stress-coupled grain growth in nanocrystalline Al
    • Gianola D S, Warner D H, Molinari J F and Hemker K J 2006 Increased strain rate sensitivity due to stress-coupled grain growth in nanocrystalline Al Scr. Mater. 55 649
    • (2006) Scr. Mater. , vol.55 , Issue.7 , pp. 649
    • Gianola, D.S.1    Warner, D.H.2    Molinari, J.F.3    Hemker, K.J.4
  • 37
    • 77958077695 scopus 로고    scopus 로고
    • Effect of normal loading on grain boundary migration and sliding in copper
    • Warner D H and Molinari J F 2008 Effect of normal loading on grain boundary migration and sliding in copper Modelling Simul. Mater. Sci. Eng. 16 075007
    • (2008) Modelling Simul. Mater. Sci. Eng. , vol.16 , Issue.7 , pp. 075007
    • Warner, D.H.1    Molinari, J.F.2
  • 38
    • 84925711387 scopus 로고
    • Hoover NPT dynamics for systems varying in shape and size
    • Melchionna S, Ciccotti G and Holian B L 1993 Hoover NPT dynamics for systems varying in shape and size Mol. Phys. 78 533
    • (1993) Mol. Phys. , vol.78 , Issue.3 , pp. 533
    • Melchionna, S.1    Ciccotti, G.2    Holian, B.L.3
  • 41
    • 0034905673 scopus 로고    scopus 로고
    • Structural stability and lattice defect in copper: Ab initio, tight-binding and embeded-atom calculations
    • Mishin Y, Mehl M J, Papaconstantopoulos D A, Voter A F and Kress J D 2001 Structural stability and lattice defect in copper: Ab initio, tight-binding and embeded-atom calculations Phys. Rev. B 63 224106
    • (2001) Phys. Rev. , vol.63 , Issue.22 , pp. 224106
    • Mishin, Y.1    Mehl, M.J.2    Papaconstantopoulos, D.A.3    Voter, A.F.4    Kress, J.D.5
  • 42
    • 0000484342 scopus 로고    scopus 로고
    • Interatomic potentials for monoatomic metals from experimental data and ab initio calculations
    • Mishin Y, Farkas D, Mehl M J and Papaconstantopoulos D A 1999 Interatomic potentials for monoatomic metals from experimental data and ab initio calculations Phys. Rev. B 59 3393
    • (1999) Phys. Rev. , vol.59 , Issue.5 , pp. 3393
    • Mishin, Y.1    Farkas, D.2    Mehl, M.J.3    Papaconstantopoulos, D.A.4
  • 43
    • 0000494238 scopus 로고
    • Molecular dynamics study of melting and freezing of small Lennard-Jones clusters
    • Honeycutt J D and Andersen H C 1987 Molecular dynamics study of melting and freezing of small Lennard-Jones clusters J. Phys. Chem. 91 4950
    • (1987) J. Phys. Chem. , vol.91 , Issue.19 , pp. 4950
    • Honeycutt, J.D.1    Andersen, H.C.2
  • 44
    • 0000554678 scopus 로고
    • Structural changes accompanying densification of random hard-sphere packings
    • Clarke A S and Jonsson H 1993 Structural changes accompanying densification of random hard-sphere packings Phys. Rev. E 47 3975
    • (1993) Phys. Rev. , vol.47 , Issue.6 , pp. 3975
    • Clarke, A.S.1    Jonsson, H.2
  • 45
    • 0000544511 scopus 로고
    • The symmetry and interfacial structure of bicrystals
    • Pond R C and Bollmann W 1979 The symmetry and interfacial structure of bicrystals Phil. Trans. R. Soc. Lond. A 292 449
    • (1979) Phil. Trans. R. Soc. Lond. , vol.292 , Issue.1395 , pp. 449
    • Pond, R.C.1    Bollmann, W.2
  • 46
    • 0000276257 scopus 로고    scopus 로고
    • 〈1 1 0〉 symmetric tilt grain-boundary structures in fcc metals with low stacking-fault energies
    • Rittner J D and Seidman D N 1996 〈1 1 0〉 symmetric tilt grain-boundary structures in fcc metals with low stacking-fault energies Phys. Rev. B 54 6999
    • (1996) Phys. Rev. , vol.54 , Issue.10 , pp. 6999
    • Rittner, J.D.1    Seidman, D.N.2
  • 47
    • 0036555633 scopus 로고    scopus 로고
    • The relation between grain-boundary structure and sliding resistance
    • Hoagland R G and Kurtz R J 2002 The relation between grain-boundary structure and sliding resistance Phil. Mag. A 82 1073
    • (2002) Phil. Mag. , vol.82 , Issue.6 , pp. 1073
    • Hoagland, R.G.1    Kurtz, R.J.2
  • 48
    • 0036856338 scopus 로고    scopus 로고
    • Thermally activated step motion observed by high-resolution electron microscopy at a (1 1 3) symmetric tilt grain-boundary in aluminium
    • Merkle K L, Thompson L J and Phillipp F 2002 Thermally activated step motion observed by high-resolution electron microscopy at a (1 1 3) symmetric tilt grain-boundary in aluminium Phil. Mag. Lett. 82 589
    • (2002) Phil. Mag. Lett. , vol.82 , Issue.11 , pp. 589
    • Merkle, K.L.1    Thompson, L.J.2    Phillipp, F.3
  • 49
    • 0018483075 scopus 로고
    • Gliding of boundary dislocations on coincidence boundaries
    • Mori T and Tangri K 1979 Gliding of boundary dislocations on coincidence boundaries Metall. Trans. A 10 733
    • (1979) Metall. Trans. , vol.10 , Issue.6 , pp. 733
    • Mori, T.1    Tangri, K.2
  • 50
    • 0039442682 scopus 로고    scopus 로고
    • Effect of extrinsic grain-boundary defects on grain-boundary sliding resistance
    • Kurtz R J, Hoagland R G and Hirth J P 1999 Effect of extrinsic grain-boundary defects on grain-boundary sliding resistance Phil. Mag. A 79 665
    • (1999) Phil. Mag. , vol.79 , Issue.3 , pp. 665
    • Kurtz, R.J.1    Hoagland, R.G.2    Hirth, J.P.3
  • 51
    • 0037174668 scopus 로고    scopus 로고
    • Ideal pure shear strength of aluminum and copper
    • Ogata S, Li J and Yip S 2002 Ideal pure shear strength of aluminum and copper Science 298 807
    • (2002) Science , vol.298 , Issue.5594 , pp. 807
    • Ogata, S.1    Li, J.2    Yip, S.3
  • 52
    • 34347356411 scopus 로고    scopus 로고
    • Stick-slip behavior of grain boundaries studied by accelerated molecular dynamics
    • Mishin Y, Suzuki A, Uberuaga B P and Voter A F 2007 Stick-slip behavior of grain boundaries studied by accelerated molecular dynamics Phys. Rev. B 75 224101
    • (2007) Phys. Rev. , vol.75 , Issue.22 , pp. 224101
    • Mishin, Y.1    Suzuki, A.2    Uberuaga, B.P.3    Voter, A.F.4
  • 53
    • 34548674407 scopus 로고
    • The structure of high-angle grain boundaries
    • Brandon D G 1966 The structure of high-angle grain boundaries Acta Metall. 14 1479
    • (1966) Acta Metall. , vol.14 , Issue.11 , pp. 1479
    • Brandon, D.G.1
  • 54
    • 54249123390 scopus 로고    scopus 로고
    • What does it mean to be special? the significance and application of the Brandon criterion
    • King A H and Shekhar S 2006 What does it mean to be special? The significance and application of the Brandon criterion J. Mater. Sci. 41 7675
    • (2006) J. Mater. Sci. , vol.41 , Issue.23 , pp. 7675
    • King, A.H.1    Shekhar, S.2
  • 55
    • 34247234615 scopus 로고    scopus 로고
    • Multiscale modelling of dislocation/grain-boundary interactions: I. Edge dislocations impinging on Σ11(1 1 3) tilt boundary in Al
    • Dewald M P and Curtin W A 2007 Multiscale modelling of dislocation/grain-boundary interactions: I. Edge dislocations impinging on Σ11(1 1 3) tilt boundary in Al Modelling Simul. Mater. Sci. Eng. 15 S193
    • (2007) Modelling Simul. Mater. Sci. Eng. , vol.15 , Issue.1 , pp. 193
    • Dewald, M.P.1    Curtin, W.A.2
  • 56
    • 34548591347 scopus 로고    scopus 로고
    • Multiscale modelling of dislocation/grain-boundary interactions: II. Screw dislocations impinge on tilt boundary in Al
    • Dewald M P and Curtin W A 2007 Multiscale modelling of dislocation/grain-boundary interactions: II. Screw dislocations impinge on tilt boundary in Al Phil. Mag. 87 4615
    • (2007) Phil. Mag. , vol.87 , Issue.30 , pp. 4615
    • Dewald, M.P.1    Curtin, W.A.2
  • 57
    • 0002467378 scopus 로고
    • Fast parallel algorithms for short-range molecular dynamics
    • Plimpton S J 1995 Fast parallel algorithms for short-range molecular dynamics J. Compt. Phys. 117 1
    • (1995) J. Compt. Phys. , vol.117 , Issue.1 , pp. 1
    • Plimpton, S.J.1
  • 58
    • 67650763351 scopus 로고    scopus 로고
    • Software available at http://lammps.sandia.gov.
  • 59
    • 0037341159 scopus 로고    scopus 로고
    • Atomeye: An efficient atomistic configuration viewer
    • Li J 2003 Atomeye: an efficient atomistic configuration viewer Modelling Simul. Mater. Sci. Eng. 11 173
    • (2003) Modelling Simul. Mater. Sci. Eng. , vol.11 , Issue.2 , pp. 173
    • Li, J.1


* 이 정보는 Elsevier사의 SCOPUS DB에서 KISTI가 분석하여 추출한 것입니다.