Unusual absorption “band” in the infrared spectrum of silicon annealed at high temperature and then rapidly cooled

1997 ◽  
Vol 31 (2) ◽  
pp. 143-145
Author(s):  
N. S. Zhdanovich
Keyword(s):  
High Temperature ◽  
Absorption Band ◽  
Infrared Spectrum

Octahedral–tetrahedral equilibria in aqueous cobalt(II) solutions at high temperatures

1980 ◽  
Vol 58 (14) ◽  
pp. 1418-1426 ◽  
Author(s):  
Thomas Wilson Swaddle ◽  
Leonard Fabes
Keyword(s):  
Sulfuric Acid ◽  
High Temperature ◽  
Absorption Band ◽  
High Temperatures ◽  
Intensity Ratio ◽  
Hydrogen Sulfate ◽  
Sulfate Ion ◽  
Acidic Media ◽  
Visible Absorption ◽  
Upper Limits

Evidence is presented to indicate that aqueous Co2+ exists as the hexaaquo-ion in equilibrium with minor amounts (upper limits 0.08% at 298 K, 7% at 625 K, at 16–25 MPa) of tetraaquocobalt(II), with ΔH ~ +17 kJ mol−1. The single visible absorption band of the supposed Co(H2O)42+ has maxima at 552 nm and 486 nm in the intensity ratio 2:1. Hydrogen sulfate ion (up to 0.5 M at least) does not complex Co2+(aq) detectably in acidic media, 290–625 K, and sulfuric acid therefore holds promise as a non-complexing strong monobasic acid for high-temperature aqueous studies. In water containing 2.0 M or more Cl−, the tetrahedral form of cobalt(II) is CoCl42−, ΔH for the octahedral → tetrahedral equilibrium being +62 kJ mol−1; forCoBr42−, the corresponding ΔH is +70 kJ mol−1, the greater endothermicity accounting entirely for the lower stability relative to CoCl42−.

High-temperature terahertz absorption band in rare-earth gallium garnet

2015 ◽  
Vol 91 (8) ◽  
Author(s):  
Masaki Adachi ◽  
Hiroaki Matsui ◽  
Munetoshi Seki ◽  
Hiroyasu Yamahara ◽  
Hitoshi Tabata
Keyword(s):  
Rare Earth ◽  
High Temperature ◽  
Absorption Band ◽  
Terahertz Absorption

High temperature infrared spectrum of the N2O molecule

1994 ◽  
Vol 52 (3-4) ◽  
pp. 439-446 ◽  
Author(s):  
H. Vilanove ◽  
M. Jacon ◽  
J.R. Jevais
Keyword(s):  
High Temperature ◽  
Infrared Spectrum

High-temperature target infrared spectrum radiance study

2013 ◽  
Author(s):  
Feifei Xu ◽  
Yong Hu ◽  
Qiu Yin ◽  
Cailan Gong ◽  
Lingya Zhu ◽  
...  
Keyword(s):  
High Temperature ◽  
Infrared Spectrum

STUDIES OF NEW SUPERCONDUCTING Bi-Sr-Ca-Cu-O SYSTEM BY INFRARED AND RAMAN SPECTROSCOPY

1988 ◽  
Vol 02 (05) ◽  
pp. 707-711 ◽  
Author(s):  
JINGQING LIU ◽  
YIFENG YAN ◽  
TANG ZHOU ◽  
GUANGCAN CHE ◽  
DAWEI CHANG ◽  
...  
Keyword(s):  
Raman Spectroscopy ◽  
Absorption Band ◽  
Infrared Spectrum ◽  
Raman Scattering ◽  
Vibrational Mode ◽  
Raman Scattering Spectrum ◽  
Infrared Transmission ◽  
Phonon Modes ◽  
Scattering Spectrum ◽  
Infrared And Raman Spectroscopy

We report both infrared transmission and Raman scattering results on the new superconducting Bi-Sr-Ca-Cu-O system. Because of its layered structure along c axis, some very thin and transparent slices have been got. In the infrared spectrum there is an absorption band around 500cm−1 with a width of about 300cm−1, and a vibrational mode at 840cm−1, higher frequency than those of phonon modes in Y-Ba-Cu-O system, has also been observed. The Raman scattering spectrum shows similar results, but the scattering signals are very weak because of the strong absorption in visible of this system.

THE INTERACTION OF SILICON TETRAFLUORIDE WITH METHANOL

1963 ◽  
Vol 41 (6) ◽  
pp. 1477-1484 ◽  
Author(s):  
J. P. Guertin ◽  
M. Onyszchuk
Keyword(s):  
Hydrogen Bonding ◽  
Magnetic Resonance ◽  
Absorption Band ◽  
Hydrogen Bonds ◽  
Infrared Spectrum ◽  
Proton Magnetic Resonance ◽  
Methanol Solution ◽  
Silicon Tetrafluoride ◽  
Conductivity Measurements ◽  
Bond Stretching

Silicon tetrafluoride reacts with methanol in a 1:4 mole ratio, forming the complex SiF4.4CH3OH, which freezes to a glass at about −20° and is completely dissociated in the gaseous phase at 25°. Conductivity measurements show clearly that it is a very weak electrolyte in methanol solution. Its infrared spectrum does not contain an Si—O bond stretching absorption band. Proton magnetic resonance measurements provide strong evidence of hydrogen bonding between silicon tetrafluoride and methanol. These results indicate that the structure of the complex requires tetracovalent rather than hexacovalent silicon and strong hydrogen bonds between methanol and each of the four fluorine atoms.

Preparation and Luminescence Properties of ZnO–SiO2–B2O3–Na2O:Sm3+ Glass

2013 ◽  
Vol 750-752 ◽  
pp. 914-918
Author(s):  
Yong Qiang Zhang ◽  
Quan Sheng Liu ◽  
Mei Li
Keyword(s):  
High Temperature ◽  
Infrared Spectrum ◽  
Glass Matrix ◽  
Emission Spectra ◽  
Spectroscopic Properties ◽  
Molar Concentration ◽  
Luminescence Properties ◽  
Melting Method ◽  
Light Excitation ◽  
Temperature Melting

The 40ZnO-30SiO2-20B2O3-10Na2O:Sm3+ glass was prepared by high-temperature melting method. The structure and composition of the glass matrix was investigated by Infrared spectrum (IR). The absorption, excitation and emission spectra of the samples were tested, and the results showed that the glass can emit orange shade under light excitation. The emission peaks at 565nm, 604nm and 650nm wavelength were corresponding to the 4G5/26H5/2, 4G5/26H7/2 and 4G5/26H9/2 transition emission of Sm3+, while the 4G5/26H7/2 transition emission was the strongest. So the best Sm3+-doping molar concentration was 0.4%. The spectroscopic properties indicated that 40ZnO-30SiO2-20B2O3-10Na2O: Sm3+ was expected to become a new conversion material.

scholarly journals Mechanism and Rheological Properties of High-Modulus Asphalt

2020 ◽  
Vol 2020 ◽  
pp. 1-13
Author(s):  
Xinquan Xu ◽  
Guilin Lu ◽  
Jun Yang ◽  
Xinhai Liu
Keyword(s):  
High Temperature ◽  
Fluorescence Microscopy ◽  
Infrared Spectrum ◽  
Dynamic Modulus ◽  
Viscoelastic Properties ◽  
Asphalt Mixture ◽  
Superior Performance ◽  
High Modulus ◽  
Modified Asphalt ◽  
Sbs Modified Asphalt

High-modulus asphalt concrete (HMAC) is considered as an effective paving material for addressing the increasing heavy traffic and rutting problems. Therefore, one high-modulus agent was used in this study to prepare high-modulus asphalt binder with different dosages. The objective of this study is to investigate the performance and modification mechanism of high-modulus asphalt. The effects of high-modulus agent on the viscoelastic properties of asphalt with different dosages were quantified via rheological tests as compared to base binder and styrene-butadiene-styrene- (SBS-) modified asphalt. Moreover, the modification mechanism of the high-modulus agent was examined using fluorescence microscopy and infrared spectrum test. Based on rutting and dynamic modulus tests, the differences of road performances between high-modulus modified asphalt mixture and SBS-modified asphalt mixture were compared. The results demonstrate that the high-modulus agent improves the high-temperature performance and viscoelastic properties of the matrix asphalt. When the dosage increases to 6.67%, the modification effect is better than that of the SBS-modified asphalt. Furthermore, the results of the rutting test show that the high-modulus modified asphalt mixture has better resistance to deformation than the SBS-modified asphalt mixture. The dynamic modulus test further demonstrates that the high-modulus modified asphalt mixture exhibits superior performance in high-temperature range. Fluorescence microscopy shows that the high-modulus agent particles can swell in the asphalt to form polymer links that improve the viscoelastic properties of the asphalt. Based on the results of the infrared spectrum test, it can be concluded that a high-modulus agent changes the asphalt matrix via physical blending modification.

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