Laʻana o nā nīnau kūkākūkā infrared
Pendahuluan
He ʻano nalu electromagnetic ka infrared me ka lōʻihi o ka nalu ma mua o ka mālamalama ʻike ʻia akā pōkole ma mua o nā nalu lekiō. He ākea nā noi o nā nalu infrared, mai ka ʻenehana a me ka lāʻau lapaʻau a hiki i ke kelepona a me ka palekana. Ma kēia ʻatikala, e kūkākūkā mākou i kekahi mau pilikia hoʻohālike e pili ana i ka infrared a me kā lākou wehewehe ʻana e hāʻawi i kahi ʻike hohonu o kēia manaʻo.
Kumumanaʻo Infrared Kumu
He nalu ko ka infrared mai 700 nanometers (nm) a i 1 millimeter (mm). Ua ʻike ʻia kēia nalu e William Herschel i ka makahiki 1800 i ka wā e hana ana i nā hoʻokolohua e ana i ka mahana o nā kala like ʻole i loko o ka spectrum mālamalama. Ua ʻike ʻo ia he kiʻekiʻe aʻe ka mahana o nā wahi ma waho o ka spectrum ʻulaʻula, ʻike ʻole ʻia e ka maka kanaka.
Ua māhele ʻia ka infrared i kekahi mau ʻāpana e pili ana i kona nalu:
1. Kokoke-Infrared (NIR): 700 nm – 1.4 µm
2. ʻĀlohilohi Waena (ʻĀlohilohi Waena, MIR): 1.4 µm – 3 µm
3. ʻĀlohilohi mamao loa (FIR): 3 µm – 1 mm
Hoʻohana nā mea hana e like me nā kāmela infrared a i ʻole thermography, nā mana mamao, a me nā kamaʻilio fiber-optic i ka ʻenehana infrared no nā kumu like ʻole. Hiki ke hoʻohana ʻia ke kukui infrared e kālailai i ka haku mele ʻana o nā mea ma o ka spectroscopy infrared.
Nā Nīnau Laʻana a me ke Kūkākūkā
Nīnau 1
Nīnau:
Hoʻohana kahi mea mamao TV i ka infrared e hoʻouna i nā hōʻailona i ke TV. Inā ʻo ka nalu o ka infrared i hoʻohana ʻia he 950 nm a ʻo ka wikiwiki o ke kukui he \(3 \times 10^8 \) m/s, he aha ke alapine (frequency) o ka nalu infrared?
Kūkākūkā:
Hiki ke helu ʻia ke alapine (frequency) o nā nalu electromagnetic me ka hoʻohana ʻana i ke ʻano kumu o ka pilina ma waena o ka nalu (\(\lambda\)) a me ke alapine (f):
\[ f = \frac{c}{\lambda} \]
me:
– \( f \) = alapine (Hz)
– \( c \) = ka wikiwiki o ka mālamalama (\(3 \times 10^8 \) m/s)
– \( \lambda \) = ka nalu (m)
Ma kēia nīnau, ua hāʻawi ʻia ka nalu (\(\lambda\)) ma nā nanometers (nm), no laila pono ka hoʻololi ʻana i nā mika (m):
950 nm = 950 manawa 10^{-9} m
I kēia manawa, hoʻololi mākou i kēia mau waiwai i loko o ke ʻano:
\[ f = \frac{3 \times 10^8 \, m/s}{950 \times 10^{-9} \, m} = 3.16 \times 10^{14} Hz \]
No laila, ʻo ke alapine (frequency) o ka nalu infrared he \(3.16 \times 10^{14} \) Hz.
Nīnau 2
Nīnau:
Hoʻohana ʻia kahi kāmela infrared e ʻike i ka radiation wela mai kahi mea. Loaʻa i ke kāmela kahi mea ʻike i nā nalu ma waena o 8 micrometers (µm) a me 14 µm. He aha ka laulā alapine (frequency) o ka radiation hiki i ke kāmela ke ʻike?
Kūkākūkā:
No ka helu ʻana i nā alapine kiʻekiʻe a me ka liʻiliʻi loa, hoʻohana mākou i ke ʻano like me ka nīnau ma mua:
\[ f = \frac{c}{\lambda} \]
ʻO ka mea mua, e hoʻololi i ka nalu mai nā micrometers (µm) i nā mika (m):
\[ 8 \, µm = 8 \times 10^{-6} \, m \]
\[ 14 \, µm = 14 \times 10^{-6} \, m \]
I kēia manawa, e helu i ke alapine kiʻekiʻe loa (\( f_{max} \)) a me ke alapine haʻahaʻa loa (\( f_{min} \)):
\[ f_{max} = \frac{3 \times 10^8 \, m/s}{8 \times 10^{-6} \, m} = 3.75 \times 10^{13} Hz \]
\[ f_{min} = \frac{3 \times 10^8 \, m/s}{14 \times 10^{-6} \, m} = 2.14 \times 10^{13} Hz \]
No laila, ʻo ka laulā alapine (frequency) i hiki ke ʻike ʻia e ke kāmela infrared ʻo \(2.14 \times 10^{13} \) Hz a i \(3.75 \times 10^{13} \) Hz.
Nīnau 3
Nīnau:
Hoʻopuka kahi mea i ka radiation infrared me ka ikaika loa ma kahi nalu o 10 µm. Ma muli o ke kānāwai neʻe ʻana o Wien, e hoʻoholo i ka mahana o ka mea. E hoʻohana i ke kūpaʻa o Wien (\(b\)) o \(2.898 \times 10^{-3} \, m \cdot K\).
Kūkākūkā:
ʻŌlelo ke kānāwai hoʻoneʻe o Wien ʻo ka huahana o ka nalu lōʻihi kahi e loaʻa ai ka ikaika radiation kiʻekiʻe loa (\(\lambda_{max}\)) a me ka mahana paʻa (T) o ka mea he mau:
\[ \lambda_{max} \cdot T = b \]
me:
– \(\lambda_{max}\) = ka nalu o ka ikaika loa (m)
– T = ka mahana o ka mea (K)
– \(b\) = ke kūpaʻa o Wien (\(2.898 \times 10^{-3} \, m \cdot K\))
Ua ʻike ʻia ʻo \(\lambda_{max}\) he 10 µm, pono e hoʻololi ʻia i mau mika:
\[ 10 \, µm = 10 \times 10^{-6} \, m \]
I kēia manawa, e pani i kēia mau waiwai i loko o ke ʻano:
\[ 10 manawa 10^{-6} \, m \cdot T = 2.898 manawa 10^{-3} \, m \cdot K \]
ʻO ka hopena no T penei:
\[ T = \frac{2.898 \times 10^{-3} \, m \cdot K}{10 \times 10^{-6} \, m} = 289.8 \, K \]
No laila, ʻo ka mahana o ka mea he 289.8 K.
Nīnau 4
Nīnau:
Nānā ʻoe i kahi spectrum infrared o kahi hui kemika organik a loaʻa kahi piko absorbance ma 3 µm. Inā ʻoe e hoʻohana ana i ka spectroscopy infrared, he aha ke ʻano o ka pilina kemika e kuleana no kēia piko?
Kūkākūkā:
Hoʻohana ka spectroscopy infrared i ka ʻoiaʻiʻo e omo nā molekala kemika i nā nalu infrared ma nā nalu kikoʻī e pili ana i nā alapine haʻalulu kūloko o nā molekala. Hiki ke hoʻopili ʻia nā nalu infrared kikoʻī me nā ʻano pili kemika kikoʻī:
– ʻO ka maʻamau, omo nā pilina CH i loko o nā hui organik i nā nalu ma kahi o 3 µm.
– ʻO ka maʻamau, omo nā mea paʻa OH i loko o nā ʻalekohola a me nā waikawa carboxylic ma kahi o 2.7-3.5 µm.
– ʻO ka maʻamau, omo nā pilina NH i loko o nā amines ma kahi o 3.1-3.3 µm.
Mai ka ʻike i hāʻawi ʻia, ʻo ka piko absorbance ma 3 µm ka mea paha ma muli o nā haʻalulu CH.
No laila, ʻo ia paha ka mea nāna e kuleana no ka piko absorbance ma 3 µm ka pilina CH i loko o ka hui kemika organik.
Ka hopena
Ma kēia ʻatikala, ua kūkākūkā mākou i kekahi mau pilikia hoʻohālike a me nā kūkākūkā e pili ana i nā nalu infrared. Ma o kēia mau hoʻohālike, hiki iā mākou ke hoʻomaopopo hou aku i nā manaʻo kumu o ke alapine (frequency), ka nalu (wavelength), a me ka mahana i loko o ka pōʻaiapili o ka radiation infrared, a me kā lākou noi ʻana i ka spectroscopy. He ʻāpana koʻikoʻi ka Infrared o ka spectrum electromagnetic a he nui nā noi ma nā ʻano like ʻole, no laila hiki i ke aʻo ʻana iā ia ke hāʻawi i nā ʻike pono i nā hanana kūlohelohe a me ka ʻenehana.
