研究生: |
張瓊云 Chang, Chiung-Yun |
---|---|
論文名稱: |
鑄造與3D列印生醫材料Ti6Al4V合金經氣體氮化及濺鍍CN與Ti-C:H鍍層後的磨潤、電化學性質與生物相容性之研究 The study of tribological, electrochemical properties and biocompatibility of casting and 3D manufacturing Ti6Al4V alloys used gas-nitrided and deposited coatings of CN and Ti-C:H |
指導教授: |
蘇演良
Su, Yen-Liang |
學位類別: |
碩士 Master |
系所名稱: |
工學院 - 機械工程學系 Department of Mechanical Engineering |
論文出版年: | 2017 |
畢業學年度: | 105 |
語文別: | 中文 |
論文頁數: | 154 |
中文關鍵詞: | Ti6Al4V 、3D列印Ti6Al4V 、表面氮化 、碳氮 、含鈦類鑽碳 、磨潤 、生物相容性 、電化學 |
外文關鍵詞: | Ti6Al4V, 3D, wear, corrosion, biocompatibility |
相關次數: | 點閱:96 下載:3 |
分享至: |
查詢本校圖書館目錄 查詢臺灣博碩士論文知識加值系統 勘誤回報 |
本研究使用非平衡磁控濺鍍法披覆碳氮(CN)於氮化熱處理前後的Ti6Al4V及3D列印Ti6Al4V以及披覆含鈦類鑽碳 (Ti-C:H) 於氮化熱處理前後的3D列印Ti6Al4V。實驗中有十二種不同的下試件,Ti6Al4V系列中有六種,分別為 Ti6Al4V (T)、氣體氮化後的Ti6Al4V (NT)、將氣體氮化Ti6Al4V降低粗糙度至原材N-Ti6Al4Vs(NTs)與披覆碳氮於三者(CN-T、CN-NT、CN-NTs);3D列印Ti6Al4V系列六種分別為3D列印Ti6Al4V(3DT)、經氣體氮化處理後的3D列印Ti6Al4V降低粗糙度至原材N-3D-Ti6Al4Vs(N3DTs)以及將前兩者披覆碳氮(CN)及含鈦類鑽碳(DLC):CN-3DT、CN-N3DTs、DLC-3DT、DLC-N3DTs。分析所有試片之微結構、機械性質,並以往復式磨耗試驗機在0.9 wt.% NaCl溶液中進行磨耗試驗,使用316L球、Si3N4球與3D列印Ti6Al4V球(3DT)三種上試件,研究其磨潤性質與磨耗機構;電化學實驗分析評估各種試片之抗腐蝕能力;培養Raw264.7小鼠單核巨噬細胞於所有試片上,探討生物相容性。
表面氮化與被覆上CN、DLC膜能夠提升抗磨耗性質、抗腐蝕性與生物相容性。在Ti6Al4V系列中由CN-NTs擁有最佳抗磨耗性與抗腐蝕性。在3D列印Ti6Al4V系列中DLC-N-3D-Ti6Al4Vs擁有最佳抗磨耗性,披覆DLC膜表現優異抗腐蝕性,鍍上CN或DLC膜之試片皆表現出良好的生物相容性。
The nitriding treatment and CN, DLC doped Ti (Ti-C:H) coatings are used for the casting and 3D manufacturing Ti6Al4V alloy. The high temperature nitriding (900°C) was applied to casting and 3D manufacturing Ti6Al4V alloy. CN and DLC coatings were deposited amorphous carbon nitride (CN) and Ti-C:H (DLC) coating used by Closed Field Unbalanced Magnetron Sputtering (CFUMBS) on unnitrided samples and nitrided specimens. The microstructure, adhesion and hardness of the CN, DLC coatings are measured by using X-ray diffraction, scratch tester and nanoindenter, respectively. The wear tests were performed by SRV tester in 0.9% NaCl solution to simulate human body environment at load of 10N for 24 min as sliding 316L, Si3N4 and 3D-Ti6Al4V balls. The corrosion resistance of all specimens was evaluated by potentiodynamic polarization test. The Purified mouse leukemic monocyte macrophage cells (Raw 264.7) are seeded on the samples for 1 day, 3 day and 5 day to investigate the biocompatibility. The result shows the duplex surface treatment effectively improved the wear, corrosion resistance and biocompatibility.
1. 國際骨質疏鬆症基金會(International Osteoporosis Foundation)12 December,2013,(http://www.iofbonehealth.org/sites/default/files/media/PDFs/Regional%20Audits/2013-Asia_Pacific_Audit-Chinese_Taipei_0_0.pdf).
2. 行政院衛生署統計公布欄,門診主要疾病就診率統計(http://www.doh.gov.tw/CHT2006/DM/DM1_2.aspx?class_no=440&level_no=1) 28 October, 2011.
3. 健保署,人工關節登錄制度
http://www.nhi.gov.tw/Information/newsdetail.aspx?menu=9&menu_id=544&No=1410
4. 林國權/工研院產經中心,材料世界網:由RAPID 2015看全球3D列印在醫療產業之應用發展趨勢。
5. 大紀元-瓷器也能「3D列印」時間人力省一半,
http://www.epochtimes.com/b5/13/5/24/n3878049.htm
6. 從首飾到義肢 3D列印將改變世界,
http://newsblog.tw/showarticle.asp?id=45050&channelid=71&lang=tw
7. P. D’Urso, W. Earwaker, T. Barker, M. Redmond, R. Thompson, D. Effeney, F. Tomlinson. Br J Plast Surg 53 (2000) 200–204.
8. S. Singare, Y. Liu, D. Li, B. Lu, J. Wang, S. He. J Prosthodont 17(2008) 135–140.
9. K. R. Dai, M. N. Yan, Z. A. Zhu, Y. H. Sun, The Journal of Arthroplasty, 22 (2007) 981–986.
10. M. Lee, C. Chang, Y. Ku. J Med Eng Technol 32 (2008) 83–90.
11. J. He, D. Li, B. Lu, Z. Wang, Z. Tao. Proc Inst Mech Eng [H] 220 (2006) 823–830.
12. Z. Wang, Y. Teng, D. Li, Journal of Reparative and Reconstructive Surgery , 18(5) (2004) 347-351.
13. F. Rengier, A. Mehndiratta, H. von Tengg-Kobligk, C. M. Zechmann, R. Unterhinninghofen, H.U. Kauczor, F. L. Giesel, Int J CARS 5(2010) 335–341.
14. I .Gibson, L.K. Cheung, S.P. Chow, W.L. Cheung, S.L. Beh, M. Savalani, S.H. Lee, Rapid Prototyping Journal, 12,1 (2006)53 – 58.
15. Mat Web, ASTM F75 Co-Cr-Mo alloy Material Property, http://www.matweb.com/search/DataSheet.aspx?MatGUID=c9345f75154b46dba09d6191c7288736
16. Mat Web, ASTM F136 Ti6Al4V-Titanium-Alloy Material Property, http://www.matweb.com/search/DataSheet.aspx?MatGUID=cdc9162a3dda4b428b0dea2ce3b105da
17. Mat Web, AISI 316L Material Property,
http://www.matweb.com/search/DataSheet.aspx?MatGUID=a2d0107bf958442e9f8db6dc9933fe31
18. YH Zhu, KY Chiu and WM Tang, Department of Orthopaedic Surgery, The University of Hong Kong, Hong Kong , “Review Article: Polyethylene wear and osteolysis in total hip arthroplasty”, Journal of Orthopaedic Surgery, 9(2001) 91-99.
19. A. Unswotih, “Recent developments in the tribology of artificial joints”, Tribology International, 28 (1995) 485-495.
20. D. Dowson, “A comparative study of the performance of metallic and ceramic femoral head components in total replacement hip joints”, Wear, 190 (1995) 171-183.
21. Bizot P, Banallec L, Sedel L, Nizard R, “Alumina-on-alumina total hip prostheses in patients 40 years of age or younger”, Clin Orthop, 379 (2000) 68-76.
22. P. Boyera, D. Hutenb, P. Loriauta, V. Lestrat a, C. Jeanrota, P. Massina, “Is alumina-on-alumina ceramic bearings total hip replacement the right choice in patients younger than 50 years of age? A 7- to 15-year follow-up study”, Orthopaedics & Traumatology: Surgery & Research, 96(2010) 616-622.
23. D.Q. Peng, T.H. Kim, J.H. Chung, J.K. Park, “Development of nitride-layer of AISI 304 austenitic stainless steel during high-temperature ammonia gas-nitriding”, Applied Surface Science, 256(2010) 7522-7529.
24. Hideaki Shibata, Keiro Tokaji, Takeshi Ogawa, Chiaki Hori, “The effect of gas nitriding on fatigue behaviour in titanium alloys”, International Journal of Fatigue, 16(1994) 370-376.
25. S.K. Wu, H.C. Lin, C.Y. Lee. “Gas nitriding of an equiatomic TiNi shape-memory alloy: Part I: Nitriding parameters and microstructure characterization” Surface and Coatings Technology, 113(1999) 17-24.
26. A.Y. Liu, M.L. Cohen, “Prediction of New Low Compressibility Solids”, Science, 245 (1989) 841-842.
27. A.Y. Liu, M.L. Cohen, “Structural-Properties and Electronic-Structure of Low-Compressibility Materials - Beta-Si3n4 and Hypothetical Beta-C3N4”, Phys. Rev, B41 (1990) 10727.
28. D. Liu, G. Benstetter, E. Lodermeier, I. Akula, I. Dudarchyk, Y. Liu, T. Ma, “SPM investigation of diamond-like carbon and carbon nitride films”, Surf. Coat.Technol, 172 (2003) 194.
29. X.L. Peng, Z.H. Baber, T.W. “Clyne, Surface roughness of diamond-like carbon films prepared using various techniques”, Surf. Coat. Technol, 138 (2001) 23.
30. K. Ogata, J.F.D. Chubaci, F. Fujimoto, “Properties of carbon nitride films with composition ratio C/N= 0.5–3.0 prepared by the ion and vapor deposition method”, J. Appl. Phys, 76 (1994) 3791.
31. A. Bousetta, M. Lu, A. Bensaoula, “Physical properties of thin carbon nitride films deposited by electron cyclotron resonance assisted vapor deposition”, J. Vac. Sci. Technol, A 13 (1995) 1639.
32. D. Li, S. Lopez, Y.W. Chung, M.S. Wong, W.D. Sproul, “Ionized magnetron sputter deposition of amorphous carbon nitride thin films”, J. Vac. Sci”. Technol, A 13 (1995) 1063.
33. A.K.M.S. Chowdhury, D.C. Cameron, M.S.J. Hashmi, M.J. Gregg, “Evidence for continuous areas of crystalline beta-C3N4 in sputter-deposited thin films”, J. Mater. Res, 14 (1999) 2359-2363.
34. T.-A. Yeh, C.-L. Lin, J.M. Sivertsen, J.H. Judy, “Durability and structure of rf sputtered carbon & ndash , nitrogen thin film overcoats on rigid disks of magnetic thin film media”, IEEE Trans. Magn. 27 (6) (1991) 5163.
35. A.K.M.S. Chowdhury, D.C. Cameron, M.S.J. Hashmi, A. Kumar, Y.-W. Chung, R.W.J. Chia (Eds.), “Hard Coatings Based on Borides, Carbides and Nitrides, The Minerals, Metals and Materials Research Society, Warrendale”, PA, 1998, p. 61.
36. M.Y. Chen, X. Lin, V.P. Dravid, Y.W. Chung, M.S. Wong, W.D. Sproul, “Synthesis and Tribological Properties of Carbon Nitride as a Novel Superhard Coating and Solid Lubricant”, Tribology Trans, 36 (3) (1993) 491.
37. R. Arvind Singh, Kyounghwan Na, Jin Woo Yi, Kwang-Ryeol Lee, Eui-Sung Yoon, “DLC nano-dot surfaces for tribological applications in MEMS devices.”Applied Surface Science, Vol. 257 (2011) 3153-3157
38. Bharat Bhushan, “Nanotribology and nanomechanics of MEMS/NEMS and BioMEMS/BioNEMS materials and devices.” Microelectronic Engineering, Vol. 84 (2006) 387-412.
39. A. Leonhardt, H. Gruger, D. Selbmann, B. Arnold, J. Thomas, Thin Solid Films, 332 (1998)69.
40. Dong-Hwan Kim, Hyoun-Ee Kim, Kwang-Ryeol Lee, Chung-Nam Whang, In-Seop Lee, Materials Science and Engineering C, 22 (2002) 9– 14.
41. 56. Morten S. Jellesen, Thomas L. Christiansen, Lisbeth Rischel Hilbert, Per Moller, Wear, 267(2009)1709–1714.
42. W. Xue, B. V. Krishna, A. Bandyopadhyay, S. Bose, Acta Biomaterialia, 3 (2007) 1007–1018.
43. R. Olivares, S.E. Rodilb, H. Arzate, Surf. Coat. Technol., 177 –178 (2004) 758–764.
44. K.G, Budinski, “Surface Engineering for Wear Resistance.” Prentice Hall, New Jersey.
45. Hamid Reza Asgari Bidhendi, Majid Pouranvari, “Corrsion Study Of Metallic Biomaterials In Simulated Body Fluid”, Metalurgija-MJoM, 17(2011) 13-22.
46. M.A. Khan, R.L. Williams, D.F. Williams, “Conjoint corrosion and wear in titanium alloys”, Biomaterials, 20 (1999) 765-772.
47. Daryl L. Roll, P.E. “Passivation and the Passive Layer”, (2010) 1-8.
48. 美國食品藥物管理局網FDA,“Safety Communication: Metal-on-Metal hip implants,(http://www.fda.gov/MedicalDevices/Safety/AlertsandNotices/ucm335775.htm) 2013/01/17.
49. 黃亮潔,“Nogo受體於脂多醣體誘發巨噬細胞移行能力中之角色研究”,台北醫學大學醫學科學研究所,2010年。
50. A. Bloyce, P.-Y. Qi, H. Dong, T. Bell, “Surface modification of titanium alloys for combined improvements in corrosion and wear resistance”, Surface and Coatings Technology, 107 (1998) 125–132.
51. I. Gurappa, “Characterization of different materials for corrosion resistance under simulated body fluid conditions”, Materials Characterization, 49 (2002) 73– 79.
52. Abdullah Shahryari, Sasha Omanovic, Jerzy A. Szpunar, “Electrochemical formation of highly pitting resistant passive films on a biomedical grade 316LVM stainless steel surface”, Materials Science and Engineering C, 28 (2008) 94–106.
53. D. Nolan a, S.W. Huang, V. Leskovsek, S. Braun, “Sliding wear of titanium nitride thin films deposited on Ti–6Al–4V alloy by PVD and plasma nitriding processes”, Surface & Coatings Technology, 200 (2006) 5698–5705.
54. Bruce R. Lanning, Ronghua Wei, “High intensity plasma ion nitriding of orthopedic materials Part II. Microstructural analysis”, Surface & Coatings Technology, 186 (2004) 314– 319.
55. V. Fouquet, L. Pichon1, M. Drouet, A. Straboni, “Plasma assisted nitridation of Ti-6Al-4V”, Applied Surface Science 221 (2004) 248–258.
56. Heajeong Lee, Heejae Kang, Jungmin Kim, Han-Kyun Shin, Junghwan Lee, Seok-Hwan Huh, Janghyun Sung b, Hyo-Jong Lee, “Inward diffusion of Al and Ti3Al compound formation in the Ti–6Al–4V alloy during high temperature gas nitriding”, Surface & Coatings Technology, 240 (2014) 221–225.
57. L. Facchini, A. Molinari, S. Höges, K. Wissenbach, Rapid Prototyping Journal, 16(2010) 450 -459.
58. M. Kanazawa, M. Iwaki, S. Minakuchi, N. Nomura, The Journal of Prosthetic Dentistry,112(2014)1441-1447.
59. M. Shunmugavea, A. Polishettya and G. Littlefaira, Procedia Technology, 20(2015)231–236.
60. D.G. Liu, J.P. Tu, C.F. Hong, C.D. Gu, Y.J. Mai, R. Chen, Appl. Surf. Sci. 257 (2010) 487.
61. Dong Li, Eric Cutiongco, Yip-Wah Chung, Ming-Show Wong, William D. Sproul,“Composition, structure and tribological properties of amorphous carbon nitride coatings”, Surface and Coatings Technology, 68/69 (1994) 611—615.
62. Toshiyuki Hayashi, Akihito Matsumuro, Mutsuo Muramatsu, Masao Kohzaki,
Katsumi Yamaguchi,“Wear resistance of carbon nitride thin films formed by ion beam assisted deposition”, Thin Solid Films 376 2000. 152-158.
63. D.G. Liu, J.P. Tu, R. Chen, C.D. Gu,“Microstructure, corrosion resistance and biocompatibility of titanium incorporated amorphous carbon nitride films”, Surface & Coatings Technology 206 (2011) 165–171.
64. S.E.Rodil, R.Olivares, H.Arzate, S.Muhl,“Properties of carbon films and their biocompatibility using in-vitro tests”, Diamond and Related Materials 12 (2003) 931–937.
65. Yangyi Xiao, Wankai Shin, Jing Luo,Yijian Liao, “The tribological performance of TiN, WC/C and DLC coatings measured by the four-ball test”, Ceramics International, 40(2014) 6919–6925.
66. N. Ueda, N. Yamauchi, T. Sone, A. Okamoto, M. Tsujikawa, “DLC film coating on plasma-carburized austenitic stainless steel”, Surface & Coatings Technology, 201(2007) 5487–5492.
67. Dong-Hwan Kim, Hyoun-Ee Kim, Kwang-Ryeol Lee, Chung-Nam Whang, In-Seop Lee, “Characterization of diamond-like carbon films deposited on commercially pure Ti and Ti–6Al–4V”, Materials Science and Engineering C, 22 (2002) 9– 14.
68. Morten S. Jellesen, Thomas L. Christiansen, Lisbeth Rischel Hilbert, Per Moller, “Erosion–corrosion and corrosion properties of DLC coated low temperature gas-nitrided austenitic stainless steel”, Wear ,267(2009) 1709–1714.
69. P. Wang, X. Wang, Y. Chen, G. Zhang, W. Liu, J. Zhang. “The effect of applied negative bias voltage on the structure of Ti-doped a-C:H films deposited by FCVA.” Applied Surface Science 253 (2007) 3722-3733.
70. R.D. Mansano, R. Ruas, A.P. Mousinho, L.S. Zambom , T.J.A. Pinto, L.H. Amoedo, M. Massi, “Use of diamond-like carbon with tungsten (W-DLC) films as biocompatible material.” Surface & Coatings Technology 202(2008) 2813-2816.
71. Heon Woong Choi, Reinhold H. Dauskardt, Seung-Cheol Lee, Kwang-Ryeol Lee, Kyu Hwan Oh. “Characteristic of silver doped DLC films on surface properties and protein adsorption.” Diamond & Related Materials 17 (2008) 252-257.
72. S. Kukieka,W. Gulbin ski, Y. Pauleau, S.N. Dub, J.J. Grob, “Composition, mechanical properties and friction behavior of nickel/hydrogenated amorphous carbon composite films.” Surf. Coat. Technol. 200 (2006) 6258-6262.
73. N. Ali, Y. Kousar, T.I. Okpalugo, V. Singh, M. Pease, A.A. Ogwu, J. Gracio, E. Titus, E.I. Meletis, M.J. Jackson, “Human micro-vascular endothelial cell seeding on Cr-DLC thin films for mechanical heart valve applications.” Thin Solid Films 515 (2006) 59-65.
74. Hyung Jin Kim, Deok Yong Yun, Won Seok Choi, Byungyou Hong. “Selective assembly of DNA using DLC film as passivation layer for the application to nano-device.” Diamond and Related Materials, 18 (2009) 1015-1018
75. P. Yang a,b, N. Huang , Y.X. Leng , Z.Q. Yao , H.F. Zhou, M. Maitz, Y. Leng , P.K. Chu, “Wettability and biocompatibility of nitrogen-doped hydrogenated amorphous carbon films: Effect of nitrogen.” Nuclear Instruments and Methods in Physics Research, 242 (2006) 22-25.
76. D. Li , S. Guruvenket , M. Azzi , J.A. Szpunar , J.E. Klemberg-Sapieha , L. Martinu , “Corrosion and tribo-corrosion behavior of a-SiCx:H, a-SiNx:H and a-SiCxNy:H coatings on SS301 substrate.” Surface & Coatings Technology, 204 (2010) 1616-1622.
77. R. Hauert, L. Knoblauch-Meyer , G. Francz, A. Schroeder , E. Wintermantel . “Tailored a-C:H coatings by nanostructuring and alloying.” Surface and Coatings Technology, 120-121 (1999) 291-296.
78. P. Vijai Bharathy, D. Nataraja, Paul K. Chub, Huaiyu Wangb, Q. Yangc, M.S.R.N. Kirand, J. Silvestre-Alberoe, D. Mangalaraj. “Effect of titanium incorporation on the structural, mechanical and biocompatible properties of DLC thin films prepared by reactive-biased target ion beam deposition method.” Applied Surface Science 257 (2010) 143-150.
79. Yang Ping , Zhou Hong-fang , Leng Yong-xiang , Wang Jing , Chen Jun-ying , Wan Guo-jiang , Sun Hong , Huang Nan. “Influence on biocompatibility: wettability of the a-C:H film.”35(2004) 2477-2478.
80. Masao Kamiya, Hideto Tanoue , Hirofumi Takikawa , Makoto Taki ,Yushi Hasegawa , Masao Kumagai, “Preparation of various DLC films by T-shaped filtered arc deposition and the effect of heat treatment on film properties.”Vacuum 83 (2009) 510-514.
81. E. P. Butler, M. G. Burke,” Chromium depletion and martensite formation at grain boundaries in sensitized austenitic stainless steel.”, Acta merall, 34 (1986), 557-570.
82. T. Arai, H. Fujita, M. Watanabe, “Evaluation of adhesion strength of thin hard coatings.” Thin Solid Films, Vol.154 (1987) 387-401.
83. Masao Kamiya, Hideto Tanoue , Hirofumi Takikawa , Makoto Taki ,Yushi Hasegawa , Masao Kumagai, “Preparation of various DLC films by T-shaped filtered arc deposition and the effect of heat treatment on film properties”, Vacuum 83 (2009) 510-514.
84. L. Facchini, E. Magalini, P. Robotti, A. Molinari, S. Hoges, K. Wissenbach,“Ductility of a Ti-6Al-4V alloy produced by selective laser melting of prealloyed powders”,Rapid Prototyping J. 16 (2010) 450–459.
85. I. Yadroitsev, P. Krakhmalev, I. Yadroitsava, “Selective laser melting of Ti6Al4V alloy for biomedical applications:Temperature monitoring and microstructural evolution”, Journal of Alloys and Compounds 583 (2014) 404–409.
86. 謝昀庭, “生醫材料 316L不銹鋼與Ti6Al4V合金經離子氮化以及氣體氮化以及濺鍍TiN後的磨耗性質、電化學性質和生物相容性之研究”, (2016), p27 。
87. H. Yoshida, A. Faust, J. Wilckens, M. Kitagawa, J. Fetto, Edmund Y.-S. Chao, “Three-dimensional dynamic hip contact area and pressuredistribution during activities of daily living”, Journal of Biomechanics ,39 (2006) 1996–2004.
88. W. W. Park, E. K. Kim, J. H. Jeon, J. Y. Choi, S. W. Moon,S. H. Lim, S. H. Han,∗ “Wear of UHMWPE against nitrogen-ion-implanted and NbN-coated Co–Cr–Mo alloy formed by plasma immersion ion implantation and deposition for artificial joints”, Applied Surface Science ,258 (2012) 8228– 8233
89. F. Yildiz , A.F. Yetim , A. Alsaran , A. Çelik ,“Plasma nitriding behavior of Ti6Al4V orthopedic alloy”, Surface & Coatings Technology 202 (2008) 2471–2476.
90. E. Celik, A.S. Demirkıran, E. Avcı,“Effect of grit blasting of substrate on the corrosion behaviour of plasma-sprayed Al2O3 coatings”, Surface and Coatings Technology 116–119 (1999) 1061–1064.
91. L. R. Hilbert, Dorthe B.R., J. Kold, L. Gram,“Influence of surface roughness of stainless steel on microbial adhesion and corrosion resistance”, International Biodeterioration & Biodegradation 52 (2003) 175 – 185.
92. C.Wei, W. J. Pan, M. S. Hung , “The effects of substrate roughness and associated surface properties on the biocompatibility of diamond-like carbon films”Surface & Coatings Technology,224 (2013) 8–17.
93. P. Yang, N. Huang, Y.X. Leng, Z.Q. Yao, H.F. Zhou, M. Maitz, Y. Leng, P.K. Chu,“Wettability and biocompatibility of nitrogen-doped hydrogenated amorphous carbon films: Effect of nitrogen”, Nuclear Instruments and Methods in Physics Research B 242 (2006) 22–25.