CINXE.COM

Just a moment...

<!DOCTYPE html><html lang="en-US"><head><title>Just a moment...</title><meta http-equiv="Content-Type" content="text/html; charset=UTF-8"><meta http-equiv="X-UA-Compatible" content="IE=Edge"><meta name="robots" content="noindex,nofollow"><meta name="viewport" content="width=device-width,initial-scale=1"><style>*{box-sizing:border-box;margin:0;padding:0}html{line-height:1.15;-webkit-text-size-adjust:100%;color:#313131;font-family:system-ui,-apple-system,BlinkMacSystemFont,Segoe UI,Roboto,Helvetica Neue,Arial,Noto Sans,sans-serif,Apple Color Emoji,Segoe UI Emoji,Segoe UI Symbol,Noto Color Emoji}body{display:flex;flex-direction:column;height:100vh;min-height:100vh}.main-content{margin:8rem auto;max-width:60rem;padding-left:1.5rem}@media (width <= 720px){.main-content{margin-top:4rem}}.h2{font-size:1.5rem;font-weight:500;line-height:2.25rem}@media (width <= 720px){.h2{font-size:1.25rem;line-height:1.5rem}}#challenge-error-text{background-image:url(data:image/svg+xml;base64,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);background-repeat:no-repeat;background-size:contain;padding-left:34px}@media (prefers-color-scheme:dark){body{background-color:#222;color:#d9d9d9}}</style><meta http-equiv="refresh" content="390"></head><body class="no-js"><div class="main-wrapper" role="main"><div class="main-content"><noscript><div class="h2"><span id="challenge-error-text">Enable JavaScript and cookies to continue</span></div></noscript></div></div><script>(function(){window._cf_chl_opt={cvId: '3',cZone: "pubs.aip.org",cType: 'managed',cRay: '918253cecbacfdac',cH: 'D73mFbGaxRO6x70SW.soahkzYEm.rrxIo30gFuhD5FI-1740597992-1.2.1.1-IE1T7R79D_qR6ISdPfk0L7dyg_RZTbRWX6QL3dKwhWQHc1mt15C7PsgUGkGbF4Hc',cUPMDTk: "\/physicstoday\/article\/63\/11\/34\/413324\/The-physics-of-boron-nitride-nanotubesAs-synthesis?__cf_chl_tk=f.3LWGoJyTC2ON.9u3pG07NAraCrJ6guWti35YrsDW0-1740597992-1.0.1.1-daTer11HBhXkUE0tiT5FIJI_G_bZQ0iIrRbOuOmQvPI",cFPWv: 'b',cITimeS: '1740597992',cTTimeMs: '1000',cMTimeMs: '390000',cTplC: 0,cTplV: 5,cTplB: 'cf',cK: "",fa: "\/physicstoday\/article\/63\/11\/34\/413324\/The-physics-of-boron-nitride-nanotubesAs-synthesis?__cf_chl_f_tk=f.3LWGoJyTC2ON.9u3pG07NAraCrJ6guWti35YrsDW0-1740597992-1.0.1.1-daTer11HBhXkUE0tiT5FIJI_G_bZQ0iIrRbOuOmQvPI",md: "Gdo.hRuJLJuutpmqD0JFG218k0xfevELzKFeHgWS72s-1740597992-1.2.1.1-LzAMJpU62w1yNe.g5HsHZ0TbXbrSj_GzAIMe6wlMa9fmEiUr6P2Ljzvw78yOwjYp0U38NCdEgyltIcwWlkm08gA3ApjRV9s9jCiAKqpvQi2opxdLVY1qulywHjxPegt0JoDDTo9ZBmypaaViWG0H1BLKqvdzfuMKcOYZfWQtZA7LSs8gY7KAxSqrNe41ZPbMa7Cz7dc1T2.KrcbZBUQtUlyFWahUlumuhv8odESVInHtLDlP1r9vVzqNcLWPPFdLp6zBNtNcrQ.uln0MMRLx.FWz3wJYVqUGs6g1vxlODGoJVqiLMhnqZquwKBPhsAEgfmmxDg7SeiTYYPXZBz12RpKti.pmlX96PDP.w.u04nrrAKoUPotU4d.t7_wKc1QKP0xKQwS5HuwidH11urBch8vUu3mGXXJAt3h9KylbU7oHLzMmf7Xqqkqx0Fu5lvs_4UDphoj81JKJGq1Ua4eL7qBmlSW_qn8wfntvPEuN6UmmHmwXbHoJ2bDTKE9hEnrMQ127pLcx6wdd.iOylAbduZb7DBzYrWHhxo8sb.LzcPzvCxsZBDMJqUfA6tvWXK30eU3POXOr_y1mwOM2SK7oTi6KHvsOXJRUNoxLsAv_A2qA8_1grUQchRQDX6fwj_tnf3GNf8xBaAOzybcjEN1Sneydi42KvmcMI7RANY0GOZz_sQIG2_MrQG41pL2Z9jH_7PZv3sLjmq_1vJd5ysNjlgqMf34pdwloHnbQ1CYMgQMnVurJmIPVr45f4QOQhGb6qOPQAiUl5G.1RJ0pdO3JDtaaRNpBOmvpj3AUXFFcY.JmDP2c8oMiP2FBJGDh.iOeEmuM.n9rg_sSGCgFQ89HDth.d2LUs8sbq770DNn.TOnq6zvzh1Ao9rEDxfv3oB8TtkDP3p1DOebhkaTq_i_S39jXXbwjJaQXYvdUVKcm608t4NhTMi3bNG_Gram.4m_kz._c8rihDwQHeT3GaeCWbXafDFjz0KzyBCvdmfGr.2sNH0gEXa.Zr8_i.q4s9ZWLcATY1vcPaIFOzMv6Y0DoWhpQsxt8cgStWmap5wb2zSfPusmDdaX3oNaI4U8uWReckbrmEm84OPYqZxROm1qVCwJgpl28wQ08_KcHwoSWRNLdnaKu2k9Tic9glxk63a_4MBy6Uu2pdMXEWr6D2LQJgyfnf2Gt9nXx8rLR1VQf0Wm.jDzRI1f2atbV1REvHW4POXcWateBTXXC320h8zVPHM2Xm5mnrCyxslpeqInlgbL4RYs29RjvPwONDgArR_HlW1RJ47s_8Y3.y3y3UihA.o1vkhQ.O8fzWFYcKwzk.TNGRvFL8ldUPiue8rm6sF2KbnV4oeeQ1bL7PT4I5OMwL79YuevExUAijz0nTs8shvQDpx.6050QZB1mCBymVXjDVumeiL65x0XQkM34qA.UTqfkrGFMXTB9Eqw93sNAGutbug71nzt_WsfUvaUH87x5TlewEbxeqa8KoTFQEG.IUeAE3Bv_yd5x0xnquv_g.IKC9vaOVRtSRIstz_wiG7ouKMlIYQeK7R5KsXPGScBA78JZ_MzJzRq4zSzy2kY596GfKgPVuVDoOcCeY1aqVCtfi2SQu99OIKPSluNoq3yEO1POWlgjD4QTzwi4AbjBX36HljTKsi_iK2uNG6XicJshxYjjFWyiPLyWAVLcoAJOiEGWZfx2.x.x6S_e99Ii.zZZsn85sknta5ksJRt5w6qQ0pbmxmUblHmM3565No7DUlOnH5kEIae97Yjl9O95c_63dcVTcV5W9WLLE5Omi79vVv.MTJa6Y72qHPrHVBwRvk7GWouWOT4v3flj1NEpc2hYRCQATzvuqsHwVbBhkGGNL82U57nKnbYWUxlPPo3BP7oveDRcZudpojLaZTo8pdCmxBThdiB4FLUPa_qy50yX8gzV1vdzEQtcxcFKEBLz2Zf1XzLjXuwJ5xGNY2_TTgcnc7q8lbGoMoLwLiv3f99hTnprsZIfh4FlbMpBJCVloTPgYNHtFyt4udye0d8R54KbYzFsLzYuyne.KHzFx1tgkF0J20GRULa9QMdAcv3IEN.c05W9Hx1mdpIHwS93ZeDVDdDn46cO8DVhnSXDFnfxrz0nNw._mgSo8dso7UrlW4RpbIL1597Tp7dff8OQHCwR45T2BF0lEWx9dj.a084L3cwDnCM0Iiy00u._52r107XuWU0S3NXmWrDcBnOlD1k5llu6azpEozQTJwU7S_zoyFnwAB4SEyAc8nhGwc59KXAh6VvZVUR5xPaCC_FTcVseE7Q.6BFxvuDWFfIzQ3E2EBW4PXR8lisp2AN10mTtAmWIELPKXNt7AYqtxZlN1WWjIE5RXevMhcaA1QePfWiQCLgQFsA48TV.cTWblV1d_5BQgbkq7C5GdAU4KMFfegSXlktBDNDyQDY7Y9H5K0VK4BxBa26jIFHtgogDnP4AIax.oOWM5vZeJnZuJ8.Bwk2xZuRftN84BxJlNTDc19UQ2wPC5Yj74L1GL28w5WiESJ0rvb0XNiy0XBJ.9K2.xPeemScX6GiMJMHRaxcyNQfxZgdrEJqyOpcDpnm_UV0VqGqxosrklJ6VwjTotWBChy20FxauzXBTBuQZMVFZaI9s5lnItrFvgoUVFIXqUWru9vqCLnz37eIj8_XkvThUCZfp3AAgGq4a2LjPVy.mqHe0CASlX5g89Ixk5eX7RwA7j1yK2CcedUSpo1H9C69vp3gBAzqwxkE4DcHLqb55FaEu",mdrd: "mr2DPa9EVWwpiKQ3Ql9mJQKZy0Imo4IgzCn8qqc2sSI-1740597992-1.2.1.1-SdYNPPhudUDsnS.Ezu1ONHxSwsKj_QeizMQiXIDl_fg_NRnMKJy1IC2Y4tFRGTfZya8dIlkFA2tfMLV2gO2RJ.SPBZlePseTTxiCCu.3J4c.xzPjf1QoqG2mwlXZ7xOpIB6VjIRMIB78u8bUJ2XCJRzStiUSzgt2k.426uGPi3Op28IzaGsPrK4.47m5uKXdto4NQCcINGs.RHR3rgggQJkq_Py176nIHy3xnewXWxTc8JEObZFKvmI_ffpGPaRKg_lSRhLnJYZsd27JKpf_NhgpYojrtSHgGuuBGhCJqPKarCoWqpN496YN5Cfx3aRMm.FSYlnHrA3OVKWDM14pj.z4H6gKTJdZRfmkex1aKFFaX52lyPVCRTNlQm_G2QjrBkVmf4yP66AZsTi2UjRwuQE8bPPpY9CrUNckQMK2A86fY2XRwBaLxigqp0yvLcWSnkllY8dZu04r1AokUg7tOSUOQt8maQgXstRkMLzQl7GgmR_Q4oKn716hIKk1H9eEGOydop4rZ9WhTZSy20LJJ.VNEprcZZWDDnGQWJpFFZNDTFnXyCcyv_LZEEvXOzpb1FwzB0cgsaZmG7fOC8oQ2dbYdz0QfVKWbhwgxS5q4r4UyA.LohvKyKUS11y8fjFGqPUoimQkjxf1_II44ZRAIsVwM2IyQT8AhPBfsCfGcV2RVs44WD89YH78YhFD1gx4OEkOVrmVWPhKyTMmPHWXsi9mQplFEd.wCAFU3Z8YzVtNqHgoqC7dTSc5nJStnrY273K3bmPq_8RVctvXTBHaT2l_Sq7HHAaplowb.7Q2KxT1FUh7rPAaU2wG0Yw5Dq0Bq8jZSk6ko0CcG5sVBjnVzouR0JcRjtlEgGCVnl1Ymp76x0qPyrtDxt5oZ.ZiixwnGGCvpHCzg2s76HXRZwmvKU2Sdy4OTtIWIiKIMmGEEkH8FdOLNCau4cjaVdQtnoRMGZCcVBWo9zc2u4uqNpze_z.0Vd9JAXZry7LBAnkQqkPCD855.AOh0MfGlxMjZEVpv3V7.Yp50zGO3pivHJWI34UGXSR_z.TSYdpynXeb25VTksEaS8.4mWyr4XFEA2NbvHN3hZleWUbjM6fFe5pIfmc3zvVjCg1KTNZ93B20NkLU.KhI0Ig2V2EM9hIfH_yqw3KhBgdQXdwvuPutIF2Fqxm94egYiK8KDdJAAsNQmcWirdV7iamkUSX5Vw8wFPeM_Y495Nrzh1ZOsVaI63v9EjIwsm40rUOnsIKdKBkHMeRERQ_7L8RjoqmIswO.AdeUtyGUjRU0uzG5SIVZt29WB.ZcxzNOayA_8lqMAiZpqrFU6VwdQF39bLF_lLPVPb8z_Dhx6mbRsrWrHrCmlCB19iFcK8PUyT7fMKNq6cFdXTjixAzcvQt4BZV5sLPvSqjccRSV9TLkc7nRnarAxsmaCeEaAS2TIr6g6vRfW0aibbs0pQqFUPvAIpfPbZzzBT_mtjL0fxI_PKP5871ZxGGumXXB9fdFIBCw1BJJAF6UFvDj4hVIT71lTsUlqn5wqgW1UhWXCvohQNtr6D1f6CGfYwuBq6PQtZbSHWcUtnCMF4y6KW2gMdkyGgJeCzi.iLa5gcx5JzU3gUewkhuySHtLxEe.15zU487PrbXWKAtioVM1imWE8c3GtmDJshl1CXm3q87nmBmc.5Pe3QL0.rXhmB5FEWfXLhwO26fRdI3IYSr6BCrjgpP1zFtRkj2Xuq6j3wvmMtcRn6voSBnchFICNJhOkXlM1zmerSbgI_e6zK7sXC53KRdbbxyvChyXje97D8cBR8fQ.7hRADuRDEB4gcUFX8juipIbVPbPNywq9EkGfXW7qFbym9lUacZXQlnaEwGMN9XZQrJgFsLWAIy8KUntqcLl.zTqYX7xl88vmLrQrAb.3ya0ZTFgn6PkYqXtSRjhAOxzZ1HGYpEMlRzp4MOnjnkMvsRIfDqmL5iw.T7Q_CTAgeLd.VEGgOT3LyQP"};var cpo = document.createElement('script');cpo.src = '/cdn-cgi/challenge-platform/h/b/orchestrate/chl_page/v1?ray=918253cecbacfdac';window._cf_chl_opt.cOgUHash = location.hash === '' && location.href.indexOf('#') !== -1 ? '#' : location.hash;window._cf_chl_opt.cOgUQuery = location.search === '' && location.href.slice(0, location.href.length - window._cf_chl_opt.cOgUHash.length).indexOf('?') !== -1 ? '?' : location.search;if (window.history && window.history.replaceState) {var ogU = location.pathname + window._cf_chl_opt.cOgUQuery + window._cf_chl_opt.cOgUHash;history.replaceState(null, null, "\/physicstoday\/article\/63\/11\/34\/413324\/The-physics-of-boron-nitride-nanotubesAs-synthesis?__cf_chl_rt_tk=f.3LWGoJyTC2ON.9u3pG07NAraCrJ6guWti35YrsDW0-1740597992-1.0.1.1-daTer11HBhXkUE0tiT5FIJI_G_bZQ0iIrRbOuOmQvPI" + window._cf_chl_opt.cOgUHash);cpo.onload = function() {history.replaceState(null, null, ogU);}}document.getElementsByTagName('head')[0].appendChild(cpo);}());</script></body></html>