Mahalo iā ʻoe no ke kākau inoa ʻana me Physics World Inā makemake ʻoe e hoʻololi i kāu kikoʻī i kēlā me kēia manawa, e kipa i kaʻu moʻokāki
Hiki i nā kiʻi kiʻi ʻoniʻoni ke pale aku i nā mea uila mai ka radiation electromagnetic (EM), akā ʻo nā ʻenehana i kēia manawa no ka hana ʻana iā lākou e lawe i kekahi mau hola a koi aku i nā mahana hana ma kahi o 3000 °C. Ua hōʻike ʻia kahi hui o nā mea noiʻi mai ka Shenyang National Laboratory for Materials Science ma ka Chinese Academy of Science i kahi ala ʻē aʻe o ka hana ʻana i nā kiʻi kiʻi kiʻi kiʻekiʻe i loko o nā kekona wale nō ma ke kinai ʻana i nā ʻāpana wela o ka nickel foil i loko o ka ethanol. ʻOi aku ka nui o ka ulu ʻana o kēia mau kiʻiʻoniʻoni ma mua o ʻelua mau kauoha o ka nui ma mua o nā ʻano hana e kū nei, a ua like ka conductivity uila a me ka ikaika mechanical o nā kiʻiʻoniʻoni me nā kiʻiʻoniʻoni i hana ʻia me ka chemical vapor deposition (CVD).
Hoʻopuka nā mea uila a pau i kekahi radiation EM. I ka liʻiliʻi ʻana o nā mea hana ma nā alapine kiʻekiʻe a kiʻekiʻe, e ulu aʻe ka hiki ke hoʻopilikia electromagnetic (EMI), a hiki ke hoʻopilikia i ka hana o ka hāmeʻa a me nā ʻōnaehana uila kokoke.
ʻO ka graphite, he allotrope o ka kalapona i kūkulu ʻia mai nā papa o ka graphene i paʻa pū ʻia e nā pūʻali van der Waals, he nui nā mea uila, wela a me nā mea hana mechanical e lilo ai ia i mea pale pono i ka EMI. Eia nō naʻe, pono ia i ke ʻano o kahi kiʻiʻoniʻoni lahilahi no ka mea e loaʻa ai kahi conductivity uila kiʻekiʻe, he mea nui ia no nā noi EMI pono no ka mea ʻo ia ka mea hiki ke hoʻohālikelike a hoʻopaʻa i nā nalu EM i ko lākou launa pū ʻana me nā mea lawe ukana i loko. ia.
I kēia manawa, ʻo nā ala nui o ka hana ʻana i nā kiʻi graphite e pili ana i ka pyrolysis wela kiʻekiʻe o nā polymers aromatic a i ʻole ka hoʻopaʻa ʻana i ka graphene (GO) oxide a i ʻole graphene nanosheets papa ma ka papa. Pono nā kaʻina ʻelua i nā wela kiʻekiʻe ma kahi o 3000 °C a me nā manawa hana o hoʻokahi hola. I loko o CVD, ʻoi aku ka haʻahaʻa o nā mahana i makemake ʻia (ma waena o 700 a 1300 °C), akā pono e hana i kekahi mau hola e hana i nā kiʻiʻoniʻoni nanometre-mānoanoa, ʻoiai i loko o ka vacuum.
He kime i alakaʻi ʻia e Wencai Ren i kēia manawa ua hana ʻia ke kiʻi graphite kiʻekiʻe he ʻumi nanometer mānoanoa i loko o kekahi mau kekona ma o ka hoʻomehana ʻana i ka nickel foil i 1200 °C i loko o ka lewa argon a laila hoʻokomo wikiwiki i kēia pahu i loko o ka ethanol ma 0 °C. ʻO nā ʻātoma kalapona i hana ʻia mai ka hoʻoheheʻe ʻana o ka ethanol e laha a hoʻoheheʻe ʻia i loko o ka nickel mahalo i ke kalapona kiʻekiʻe o ka metala (0.4 wt% ma 1200 °C). Ma muli o ka emi nui ʻana o kēia hoʻoheheʻe kalapona i ka haʻahaʻa haʻahaʻa, hoʻokaʻawale a hoʻoheheʻe nā ʻātoma kalapona mai ka ʻili nickel i ka wā e kinai ana, e hana ana i kahi kiʻi graphite mānoanoa. Ua hōʻike nā mea noiʻi ʻo ka hana catalytic maikaʻi loa o ka nickel e kōkua pū i ka hoʻokumu ʻana i ka graphite crystalline.
Ke hoʻohana nei i ka hui pū ʻana o ka microscopy hoʻouna kiʻekiʻe, X-ray diffraction a me Raman spectroscopy, ua ʻike ʻo Ren a me nā hoa hana ʻo ka graphite a lākou i hana ai he crystalline nui loa ma nā wahi nui, ua hoʻopaʻa maikaʻi ʻia a ʻaʻohe hemahema ʻike ʻia. Ua like ke kiʻekiʻe o ka conductivity electron o ke kiʻiʻoniʻoni e like me 2.6 x 105 S/m, e like me nā kiʻiʻoniʻoni i ulu ʻia e CVD a i ʻole nā ʻenehana wela kiʻekiʻe a me ke kaomi ʻana i nā kiʻi ʻoniʻoni GO/graphene.
No ka hoʻāʻo ʻana i ka maikaʻi o ka mea hiki ke ālai i ka radiation EM, ua hoʻoili ka hui i nā kiʻiʻoniʻoni me ka ʻili o 600 mm2 ma luna o nā substrate i hana ʻia me ka polyethylene terephthalate (PET). A laila ana lākou i ka pono pale pale EMI o ke kiʻiʻoniʻoni (SE) ma ka laina alapine X-band, ma waena o 8.2 a me 12.4 GHz. Ua loaʻa iā lākou kahi EMI SE ma mua o 14.92 dB no kahi kiʻiʻoniʻoni ma kahi o 77 nm mānoanoa. Piʻi kēia waiwai i ʻoi aku ma mua o 20 dB (ka waiwai liʻiliʻi i koi ʻia no nā noi kalepa) i ka hui X holoʻokoʻa i ka wā i hoʻopaʻa pū ai lākou i nā kiʻiʻoniʻoni hou aʻe. ʻOiaʻiʻo, ʻo kahi kiʻiʻoniʻoni i loaʻa i ʻelima mau ʻāpana kiʻi kiʻi ʻoniʻoni i hoʻopaʻa ʻia (ma kahi o 385 nm mānoanoa i ka huina) he EMI SE ma kahi o 28 dB, ʻo ia hoʻi ka mea hiki ke kāohi i ka 99.84% o ka radiation hanana. Ma ke ʻano holoʻokoʻa, ua ana ka hui i kahi pale EMI o 481,000 dB/cm2/g ma o ka X-band, ʻoi aku ka maikaʻi o nā mea synthetic i hōʻike mua ʻia.
'Ōlelo nā mea noiʻi i ka maikaʻi o ko lākouʻike,ʻo kā lākou kiʻi graphite ka mea lahilahi ma waena o nā mea pale i hōʻikeʻia, me kahi hana pale EMI e hiki ai ke hoʻokō i nā koi no nāʻoihana kālepa. He mea maikaʻi nō hoʻi kona ʻano mechanical. ʻOi aku ka kiʻekiʻe o ka ikaika haʻihaʻi o ka mea ma kahi o 110 MPa (unuhi ʻia mai nā ʻāpana koʻikoʻi o ka mea i kau ʻia ma ke kākoʻo polycarbonate) ma mua o nā kiʻi graphite i ulu ʻia e nā ʻano hana ʻē aʻe. Hiki ke hoʻololi ʻia ke kiʻiʻoniʻoni, a hiki ke hoʻopiʻi ʻia i nā manawa 1000 me ka radius kulou o 5 mm me ka nalowale ʻole o kāna mau mea pale EMI. He paʻa nō hoʻi ka thermally a hiki i 550 °C. Ke manaʻoʻiʻo nei ka hui ʻo kēia mau mea a me nā waiwai ʻē aʻe e hiki ke hoʻohana ʻia ma ke ʻano he ultrathin, māmā, maʻalahi a me ka maikaʻi o nā mea pale EMI no nā noi ma nā wahi he nui, me ka aerospace a me ka uila a me ka optoelectronics.
E heluhelu i nā holomua nui loa a me ka hoihoi o ka ʻepekema waiwai ma kēia puke puke puka hou.
Hōʻike ka Physics World i kahi ʻāpana koʻikoʻi o ka misionari a IOP Publishing e kamaʻilio i ka noiʻi honua a me nā mea hou i ka lehulehu ākea. ʻO ka pūnaewele kahi ʻāpana o ka Physics World portfolio, kahi hōʻiliʻili o nā lawelawe ʻike pūnaewele, kikohoʻe a paʻi no ke kaiāulu ʻepekema honua.
Ka manawa hoʻouna: Mei-07-2020