메뉴 건너뛰기




Volumn 133, Issue 2, 2011, Pages

Synthesis and tribological properties of S- and P-free borate esters with different chain lengths

Author keywords

borate ester; lubricating additive; synthesis; tribological properties

Indexed keywords

ALKYL CHAIN LENGTHS; ANTIWEAR ABILITY; ANTIWEAR PERFORMANCE; ATOMIC RADIUS; BORATE ESTERS; BORIC ACIDS; CHEMICAL COMPONENT; CHEMICAL STRUCTURE; ELECTRON-DEFICIENT; ELEMENTAL ANALYSIS; ETHANOLAMINES; FOUR-BALL; FOURIER TRANSFORMATIONS; FRICTION AND WEAR; INFRARED SPECTROMETRY; LIQUID PARAFFINS; LOW CONCENTRATIONS; LUBRICATING ADDITIVE; LUBRICATING OIL ADDITIVES; REDUCING WEAR; SCANNING ELECTRON MICROSCOPE; STARTING MATERIALS; STEEL BALLS; STEEL SURFACE; SYNTHESIS; THERMAL STABILITY; TRIBOLOGICAL PROPERTIES; WORN SURFACE;

EID: 79953108223     PISSN: 07424787     EISSN: 15288897     Source Type: Journal    
DOI: 10.1115/1.4003304     Document Type: Article
Times cited : (25)

References (38)
  • 1
    • 42549133926 scopus 로고    scopus 로고
    • Low- and zero-sulphated ash, phosphorus and sulphur anti-wear additives for engine oils
    • DOI 10.1002/ls.57
    • Spikes, H., 2008, "Low-and Zero-Sulphated Ash, Phosphorus and Sulphur Anti-Wear Additives for Engine Oils, " Lubr. Sci., 20(2), pp. 103-136. (Pubitemid 351578622)
    • (2008) Lubrication Science , vol.20 , Issue.2 , pp. 103-136
    • Spikes, H.1
  • 2
    • 3042697466 scopus 로고    scopus 로고
    • The tribochemical study of some N-containing heterocyclic compounds as lubricating oil additives
    • DOI 10.1023/A:1020100631716
    • He, Z., Rao, W., Ren, T., Liu, W., and Xue, Q., 2002, "The Tribochemical Study of Some N-Containing Heterocyclic Compounds as Lubricating Oil Additives, " Tribol. Lett., 13(2), pp. 87-93. (Pubitemid 41450854)
    • (2002) Tribology Letters , vol.13 , Issue.2 , pp. 87-93
    • He, Z.1    Rao, W.2    Ren, T.3    Liu, W.4    Xue, Q.5
  • 4
    • 33745800042 scopus 로고    scopus 로고
    • Tribochemistry and antiwear mechanism of organic-inorganic nanoparticles as lubricant additives
    • DOI 10.1007/s11249-005-9002-7
    • Li, B., Wang, X., Liu, W., and Xue, Q., 2006, "Tribochemistry and Antiwear Mechanism of Organic-Inorganic Nanoparticles as Lubricant Additives, " Tribol. Lett., 22(1), pp. 79-84. (Pubitemid 44018837)
    • (2006) Tribology Letters , vol.22 , Issue.1 , pp. 79-84
    • Li, B.1    Wang, X.2    Liu, W.3    Xue, Q.4
  • 5
    • 33947134312 scopus 로고    scopus 로고
    • 2 nanocrystals as grease additives
    • DOI 10.1016/j.triboint.2006.12.003, PII S0301679X06003677
    • Wang, L., Wang, B., Wang, X., and Liu, W., 2007, "Tribological Investigation of CaF2 Nanocrystals as Grease Additives, " Tribol. Int., 40(7), pp. 1179-1185. (Pubitemid 46412622)
    • (2007) Tribology International , vol.40 , Issue.7 , pp. 1179-1185
    • Wang, L.1    Wang, B.2    Wang, X.3    Liu, W.4
  • 6
    • 15844385989 scopus 로고    scopus 로고
    • Recent achievements in the synthesis and application of inorganic nanoparticles as lubricant components
    • Bakunin, V. N., Suslov, A. Yu., Kuzmina, G. N., and Parenago, O. P., 2005, "Recent Achievements in the Synthesis and Application of Inorganic Nanoparticles as Lubricant Components, " Lubr. Sci., 17(2), pp. 127-145.
    • (2005) Lubr. Sci. , vol.17 , Issue.2 , pp. 127-145
    • Bakunin, V.N.1    Suslov, A.Y.2    Kuzmina, G.N.3    Parenago, O.P.4
  • 7
    • 0037300172 scopus 로고    scopus 로고
    • Tribological properties of P-and N-containing organic compounds as potential extreme-pressure and antiwear additives
    • Xia, Y., Liu, W., and Xue, Q., 2003, "Tribological Properties of P-and N-Containing Organic Compounds as Potential Extreme-Pressure and Antiwear Additives, " Lubr. Sci., 15(2), pp. 173-183.
    • (2003) Lubr. Sci. , vol.15 , Issue.2 , pp. 173-183
    • Xia, Y.1    Liu, W.2    Xue, Q.3
  • 8
    • 0027578807 scopus 로고
    • The effect of molecular structure of N-containing heterocyclic compounds on their wear properties
    • Ren, T., Liu, W., Xue, Q., and Wang, H., 1993, "The Effect of Molecular Structure of N-Containing Heterocyclic Compounds on Their Wear Properties, " Lubr. Sci., 5(3), pp. 205-212.
    • (1993) Lubr. Sci. , vol.5 , Issue.3 , pp. 205-212
    • Ren, T.1    Liu, W.2    Xue, Q.3    Wang, H.4
  • 9
    • 0036771957 scopus 로고    scopus 로고
    • Tribological evaluation of S-(1H-benzotriazole-1-yl) methyl N,N-dialkyldithiocarbamates as additives in rapeseed oil
    • DOI 10.1016/S0043-1648(02)00227-2, PII S0043164802002272
    • Li, J., Zhang, Y., Ren, T., Liu, W., and Fu, X., 2002, "Tribological Evaluation of S-(1H-Benzotriazole-1-yl) Methyl N, N-Dialkyldithiocarbamates as Additives in Rapeseed Oil, " Wear, 253 (7-8), pp. 720-724. (Pubitemid 35274046)
    • (2002) Wear , vol.253 , Issue.7-8 , pp. 720-724
    • Li, J.1    Zhang, Y.2    Ren, T.3    Liu, W.4    Fu, X.5
  • 10
    • 43249131604 scopus 로고    scopus 로고
    • Tribological evaluation of α, ω-diimidazoliumalkylene hexafluorophosphate ionic liquid and benzotriazole as additive
    • Yu, B., Zhou, F., Pang, C., Wang, B., Liang, Y., and Liu, W., 2008, "Tribological Evaluation of α, ω-Diimidazoliumalkylene Hexafluorophosphate Ionic Liquid and Benzotriazole as Additive, " Tribol. Int., 41(8), pp. 797-801.
    • (2008) Tribol. Int. , vol.41 , Issue.8 , pp. 797-801
    • Yu, B.1    Zhou, F.2    Pang, C.3    Wang, B.4    Liang, Y.5    Liu, W.6
  • 11
    • 0032989155 scopus 로고    scopus 로고
    • A tribological study of an S, P-containing benzotriazole derivative as an additive in pentaerythritol ester
    • Tianhui R., Jian, X., and Longzhen, Z., 1999, "A Tribological Study of an S, P-Containing Benzotriazole Derivative as an Additive in Pentaerythritol Ester, " Synth. Lubr., 15(4), pp. 263-269.
    • (1999) Synth. Lubr. , vol.15 , Issue.4 , pp. 263-269
    • Tianhui, R.1    Jian, X.2    Longzhen, Z.3
  • 12
    • 0028532408 scopus 로고
    • The tribological study of S-(1H-benzotriazol-1-yl) methyl N, N-dialkyldithiocarbamates as additives in synthetic lubricants
    • Ren, T., Xue, Q., and Wang, H., 1994, "The Tribological Study of S-(1H-Benzotriazol-1-yl) Methyl N, N-Dialkyldithiocarbamates as Additives in Synthetic Lubricants, " Synth. Lubr., 11(3), pp. 207-214.
    • (1994) Synth. Lubr. , vol.11 , Issue.3 , pp. 207-214
    • Ren, T.1    Xue, Q.2    Wang, H.3
  • 13
    • 0034238125 scopus 로고    scopus 로고
    • The performance and antiwear mechanism of (2-sulfurone-benzothiazole)-3- methyl esters as additives in synthetic lubricant
    • Huang, W., Dong, J., Li, F., and Chen, B., 2000, "The Performance and Antiwear Mechanism of (2-Sulfurone-Benzothiazole)-3-Methyl Esters as Additives in Synthetic Lubricant, " Tribol. Int., 33(8), pp. 553-557.
    • (2000) Tribol. Int. , vol.33 , Issue.8 , pp. 553-557
    • Huang, W.1    Dong, J.2    Li, F.3    Chen, B.4
  • 14
    • 0033237670 scopus 로고    scopus 로고
    • Tribological properties of the film formed by 2-(n-Dodecyldithio)- benzothiazole as additive in liquid paraffin
    • DOI 10.1016/S0043-1648(99)00258-6, PII S0043164899002586
    • Zhang, J., Liu, W., and Xue, Q., 1999, "Tribological Properties of the Film Formed by 2-(n-Dodecyldithio)-Benzothiazole as Additive in Liquid Paraffin, " Wear, 236 (1-2), pp. 34-38. (Pubitemid 30087152)
    • (1999) Wear , vol.236 , Issue.1-2 , pp. 34-38
    • Zhang, J.1    Liu, W.2    Xue, Q.3
  • 15
    • 0035543922 scopus 로고    scopus 로고
    • A tribological study of (2-sulphurone-benzothiazole)-3-methyl-dibutyl borate
    • Weijiu, H., Junxiu, D., Fenfang, L., Guoxu, C., and Boshui, C., 2001, "A Tribological Study of (2-Sulphurone-Benzothiazole)-3-Methyl-Dibutyl Borate, " Lubr. Sci., 14(1), pp. 73-81.
    • (2001) Lubr. Sci. , vol.14 , Issue.1 , pp. 73-81
    • Weijiu, H.1    Junxiu, D.2    Fenfang, L.3    Guoxu, C.4    Boshui, C.5
  • 16
    • 3042779752 scopus 로고    scopus 로고
    • Study of the tribological behaviors of S, P-containing triazine derivatives as additives in rapeseed oil
    • DOI 10.1016/j.wear.2004.01.013, PII S0043164804000031
    • He, Z., Lu, J., Zeng, X., Shao, H., Ren, T., and Liu, W., 2004, "Study of the Tribological Behaviors of S, P-Containing Triazine Derivatives as Additives in Rapeseed Oil, " Wear, 257 (3-4), pp. 389-394. (Pubitemid 38870682)
    • (2004) Wear , vol.257 , Issue.3-4 , pp. 389-394
    • He, Z.1    Lu, J.2    Zeng, X.3    Shao, H.4    Ren, T.5    Liu, W.6
  • 17
    • 1242310572 scopus 로고    scopus 로고
    • The tribological behaviour of some triazine-dithiocarbamate derivatives as additives in vegetable oil
    • DOI 10.1016/S0043-1648(03)00372-7
    • Zhan, W., Song, Y., Ren, T., and Liu, W., 2004, "The Tribological Behaviour of Some Triazine-Dithiocarbamate Derivatives as Additives in Vegetable Oil, " Wear, 256 (3-4), pp. 268-274. (Pubitemid 38285900)
    • (2004) Wear , vol.256 , Issue.3-4 , pp. 268-274
    • Zhan, W.1    Song, Y.2    Ren, T.3    Liu, W.4
  • 18
    • 33748973382 scopus 로고    scopus 로고
    • The tribological behaviors of hydroxyl-containing dithiocarbamate- triazine derivatives as additives in rapeseed oil
    • DOI 10.1016/j.triboint.2006.05.005, PII S0301679X06002027
    • Zeng, X., Li, J., Wu, X., Ren, T., and Liu, W., 2007, "The Tribological Behaviors of Hydroxyl-Containing Dithiocarbamate-Triazine Derivatives as Additives in Rapeseed Oil, " Tribol. Int., 40(3), pp. 560-566. (Pubitemid 44442575)
    • (2007) Tribology International , vol.40 , Issue.3 , pp. 560-566
    • Zeng, X.1    Li, J.2    Wu, X.3    Ren, T.4    Liu, W.5
  • 19
    • 33846296613 scopus 로고    scopus 로고
    • Tribological behavior of three novel triazine derivatives as additives in rapeseed oil
    • DOI 10.1016/j.wear.2006.08.004, PII S0043164806003097
    • Zeng, X., Wu, H., Yi, H., and Ren, T., 2007, "Tribological Behavior of Three Novel Triazine Derivatives as Additives in Rapeseed Oil, " Wear, 262 (5-6), pp. 718-726. (Pubitemid 46123440)
    • (2007) Wear , vol.262 , Issue.5-6 , pp. 718-726
    • Zeng, X.1    Wu, H.2    Yi, H.3    Ren, T.4
  • 20
    • 14644404319 scopus 로고    scopus 로고
    • A study of the synergistic effect of a triazine-dithiocarbamate derivative with TCP in vegetable oil
    • He, Z., Song, Y., Shao, H., Zhan, W., and Ren, T., 2005, "A Study of the Synergistic Effect of a Triazine-Dithiocarbamate Derivative With TCP in Vegetable Oil, " Synth. Lubr., 21(4), pp. 287-297.
    • (2005) Synth. Lubr. , vol.21 , Issue.4 , pp. 287-297
    • He, Z.1    Song, Y.2    Shao, H.3    Zhan, W.4    Ren, T.5
  • 21
    • 33645098823 scopus 로고    scopus 로고
    • Alkyloxy-S-Triazine derivatives with and without fluorine-containing substituents as lubricants for steel-steel contact
    • Zeng, X., Wang, Y., Wu, X., Ren, T., and He, Z., 2006, "Alkyloxy-S-Triazine Derivatives With and Without Fluorine-Containing Substituents as Lubricants for Steel-Steel Contact, " Synth. Lubr., 23(1), pp. 1-10.
    • (2006) Synth. Lubr. , vol.23 , Issue.1 , pp. 1-10
    • Zeng, X.1    Wang, Y.2    Wu, X.3    Ren, T.4    He, Z.5
  • 22
    • 0041763415 scopus 로고    scopus 로고
    • The friction and wear behavior of 2-(n-alkyldithio)-benzimidazole as additives in liquid paraffin
    • Xue, Q., Zhang, J., Liu, W., and Yang, S., 1999, "The Friction and Wear Behavior of 2-(n-Alkyldithio)-Benzimidazole as Additives in Liquid Paraffin, " Tribol. Lett., 7(1), pp. 27-30.
    • (1999) Tribol. Lett. , vol.7 , Issue.1 , pp. 27-30
    • Xue, Q.1    Zhang, J.2    Liu, W.3    Yang, S.4
  • 23
    • 68149179812 scopus 로고    scopus 로고
    • The tribological chemistry of the oil blends of zinc dialkyldithiophosphate with 2-mercaptobenzothiazole derivatives
    • Wu, H., Ren, T., and Zuo, G., 2009, "The Tribological Chemistry of the Oil Blends of Zinc Dialkyldithiophosphate With 2-Mercaptobenzothiazole Derivatives, " Tribol. Lett., 35(3), pp. 171-179.
    • (2009) Tribol. Lett. , vol.35 , Issue.3 , pp. 171-179
    • Wu, H.1    Ren, T.2    Zuo, G.3
  • 24
    • 55249084394 scopus 로고    scopus 로고
    • Tribological study of novel S-N style 1, 3, 4-thiadiazole-2-thione derivatives in rapeseed oil
    • Zhu, F., Fan, W., Wang, A., and Zhu, Y., 2009, "Tribological Study of Novel S-N Style 1, 3, 4-Thiadiazole-2-Thione Derivatives in Rapeseed Oil, " Wear, 266 (1-2), pp. 233-238.
    • (2009) Wear , vol.266 , Issue.1-2 , pp. 233-238
    • Zhu, F.1    Fan, W.2    Wang, A.3    Zhu, Y.4
  • 25
    • 0036465468 scopus 로고    scopus 로고
    • Lubrication potential of boron compounds: An overview
    • Choudhary, R. B., and Pande, P. P., 2002, "Lubrication Potential of Boron Compounds: An Overview, " Lubr. Sci., 14(2), pp. 211-222. (Pubitemid 34239890)
    • (2002) Lubrication Science , vol.14 , Issue.2 , pp. 211-222
    • Choudhary, R.B.1    Pande, P.P.2
  • 26
    • 64749102402 scopus 로고    scopus 로고
    • Tribological properties and action mechanism of N, N-dialkyl dithiocarbamate-derived S-hydroxyethyl borate esters as additives in rapeseed oil
    • Sun, Y., Hu, L., and Xue, Q., 2009, "Tribological Properties and Action Mechanism of N, N-Dialkyl Dithiocarbamate-Derived S-Hydroxyethyl Borate Esters as Additives in Rapeseed Oil, " Wear, 266 (9-10), pp. 917-924.
    • (2009) Wear , vol.266 , Issue.9-10 , pp. 917-924
    • Sun, Y.1    Hu, L.2    Xue, Q.3
  • 27
    • 0036525604 scopus 로고    scopus 로고
    • The tribological behaviour and mechanism of action of sulphur-containing borate esters in rape seed oil
    • Gong, Q., Yu, L., and Ye, C., 2002, "The Tribological Behavior and Mechanism of Action of Sulphur-Containing Borate Esters in Rape Seed Oil, " Synth. Lubr., 19(1), pp. 19-30. (Pubitemid 34523409)
    • (2002) Journal of Synthetic Lubrication , vol.19 , Issue.1 , pp. 19-30
    • Gong, Q.1    Yu, L.2    Ye, C.3
  • 28
    • 34047217328 scopus 로고    scopus 로고
    • Synthesis and performance of nitrogen-containing borate as lubricant additive
    • Chinese
    • Tan, X., Liu, J., and Guo, Y., 2005, "Synthesis and Performance of Nitrogen-Containing Borate as Lubricant Additive, " Applied Science and Technology, 32(2), pp. 59-61 (in Chinese).
    • (2005) Applied Science and Technology , vol.32 , Issue.2 , pp. 59-61
    • Tan, X.1    Liu, J.2    Guo, Y.3
  • 29
    • 0032216370 scopus 로고    scopus 로고
    • Synthesis, hydrolytic stability and tribological properties of novel borate esters containing nitrogen as lubricant additives
    • DOI 10.1016/S0043-1648(98)00323-8, PII S0043164898003238
    • Zheng, Z., Shen, G., Wan, Y., Cao, L., Xu, X., Yue, Q., and Sun, T., 1998, "Synthesis, Hydrolytic Stability and Tribological Properties of Novel Borate Esters Containing Nitrogen as Lubricant Additives, " Wear, 222(2), pp. 135-144. (Pubitemid 29099470)
    • (1998) Wear , vol.222 , Issue.2 , pp. 135-144
    • Zheng, Z.1    Shen, G.2    Wan, Y.3    Cao, L.4    Xu, X.5    Yue, Q.6    Sun, T.7
  • 30
    • 0035384859 scopus 로고    scopus 로고
    • Preparation of Ni nanoparticles and evaluation of their tribological performance as potential additives in oils
    • Qiu, S., Zhou, Z., Dong, J., and Chen, G., 2001, "Preparation of Ni Nanoparticles and Evaluation of Their Tribological Performance as Potential Additives in Oils, " ASME J. Tribol., 123(3), pp. 441-443. (Pubitemid 32696571)
    • (2001) Journal of Tribology , vol.123 , Issue.3 , pp. 441-443
    • Qiu, S.1    Zhou, Z.2    Dong, J.3    Chen, G.4
  • 31
    • 79953107696 scopus 로고    scopus 로고
    • The tribological study of organic borate esters as additives in rapeseed oil
    • Li, J., Feng, Y., and Ren, T., 2004, "The Tribological Study of Organic Borate Esters as Additives in Rapeseed Oil, " Lubricating Oil, 19(2), pp. 32-34.
    • (2004) Lubricating Oil , vol.19 , Issue.2 , pp. 32-34
    • Li, J.1    Feng, Y.2    Ren, T.3
  • 32
    • 47949116049 scopus 로고    scopus 로고
    • Tribological characteristics of ashless dithiocarbamate derivatives and their combinations with ZDDP as additives in mineral oil
    • Fan, K., Li, J., Ma, H., Wu, H., Ren, T., Kasrai, M., and Bancroft, G. M., 2008, "Tribological Characteristics of Ashless Dithiocarbamate Derivatives and Their Combinations With ZDDP as Additives in Mineral Oil, " Tribol. Int., 41(12), pp. 1226-1231.
    • (2008) Tribol. Int. , vol.41 , Issue.12 , pp. 1226-1231
    • Fan, K.1    Li, J.2    Ma, H.3    Wu, H.4    Ren, T.5    Kasrai, M.6    Bancroft, G.M.7
  • 33
    • 71549137806 scopus 로고    scopus 로고
    • Friction and wear behavior of diamond-like carbon coating on plasma nitrided mild steel under boundary lubrication
    • Jia, Z., Xia, Y., Li, J., Pang, X., and Shao, X., 2010, "Friction and Wear Behavior of Diamond-Like Carbon Coating on Plasma Nitrided Mild Steel Under Boundary Lubrication, " Tribol. Int., 43 (1-2), pp. 474-482.
    • (2010) Tribol. Int. , vol.43 , Issue.1-2 , pp. 474-482
    • Jia, Z.1    Xia, Y.2    Li, J.3    Pang, X.4    Shao, X.5
  • 34
    • 10844264313 scopus 로고    scopus 로고
    • Tribological properties and tribochemical mechanism of lanthanum and boron compounds in oil
    • Jiang, S., Wei, Y. L., Cheng, X. Y., and Chen, B. S., 2004, "Tribological Properties and Tribochemical Mechanism of Lanthanum and Boron Compounds in Oil, " Lubr. Sci., 17(1), pp. 63-73. (Pubitemid 40002913)
    • (2004) Lubrication Science , vol.17 , Issue.1 , pp. 63-73
    • Jiang, S.1    Wei, Y.L.2    Cheng, X.Y.3    Chen, B.S.4
  • 35
    • 4143110076 scopus 로고    scopus 로고
    • The synthesis and tribological behaviour of boron-nitrogen-modified fatty acid water-based lubricant additives
    • Hua, F. J., Bo-Shui, C., Lin, D., Jiu, W., and Wei-Jiu, H., 2004, "The Synthesis and Tribological Behaviour of Boron-Nitrogen-Modified Fatty Acid Water-Based Lubricant Additives, " Synth. Lubr., 21(2), pp. 129-137.
    • (2004) Synth. Lubr. , vol.21 , Issue.2 , pp. 129-137
    • Hua, F.J.1    Bo-Shui, C.2    Lin, D.3    Jiu, W.4    Wei-Jiu, H.5
  • 36
    • 65349101705 scopus 로고    scopus 로고
    • Tribological performances of heterocyclic-containing ether and/or thioether as additives in the synthetic diester
    • Liang, P., Wu, H., Zuo, G., and Ren, T., 2009, "Tribological Performances of Heterocyclic-Containing Ether and/or Thioether as Additives in the Synthetic Diester, " Lubr. Sci., 21(3), pp. 111-121.
    • (2009) Lubr. Sci. , vol.21 , Issue.3 , pp. 111-121
    • Liang, P.1    Wu, H.2    Zuo, G.3    Ren, T.4
  • 37
    • 65449164146 scopus 로고    scopus 로고
    • Synthesis of ultrathin carbon films by direct current filtered cathodic vacuum Arc
    • Zhang, H.-S., and Komvopoulos, K., 2009, "Synthesis of Ultrathin Carbon Films by Direct Current Filtered Cathodic Vacuum Arc, " J. Appl. Phys., 105(8), p. 083305.
    • (2009) J. Appl. Phys. , vol.105 , Issue.8 , pp. 083305
    • Zhang, H.-S.1    Komvopoulos, K.2
  • 38
    • 77955264739 scopus 로고    scopus 로고
    • Tribological behavior of plasma nitrided 1Cr18Ni9Ti austenitic stainless steel under the effect of lubricant additives
    • Fang, J., Xia, Y., Lin, Y., and Liu, W., 2009, "Tribological Behavior of Plasma Nitrided 1Cr18Ni9Ti Austenitic Stainless Steel Under the Effect of Lubricant Additives, " ASME J. Tribol., 131(3), p. 031603.
    • (2009) ASME J. Tribol. , vol.131 , Issue.3 , pp. 031603
    • Fang, J.1    Xia, Y.2    Lin, Y.3    Liu, W.4


* 이 정보는 Elsevier사의 SCOPUS DB에서 KISTI가 분석하여 추출한 것입니다.