scholarly journals Selective, Room-Temperature Transformation of Methane to C1 Oxygenates by Deep UV Photolysis over Zeolites

2011 ◽  
Vol 133 (43) ◽  
pp. 17257-17261 ◽  
Author(s):  
Francesc Sastre ◽  
Vicente Fornés ◽  
Avelino Corma ◽  
Hermenegildo García
Keyword(s):  
Room Temperature ◽  
Uv Photolysis ◽  
Temperature Transformation ◽  
Deep Uv

Evidence for ordered Fe3Ni

1987 ◽  
Vol 45 ◽  
pp. 216-217
Author(s):  
K.B. Reuter ◽  
D.B. Williams ◽  
J.I. Goldstein
Keyword(s):  
Experimental Data ◽  
Martensitic Transformation ◽  
Electron Diffraction ◽  
Room Temperature ◽  
Direct Evidence ◽  
Transformation Product ◽  
Iron Meteorites ◽  
X Ray ◽  
Ni Content ◽  
Temperature Transformation

In the Fe-Ni system, although ordered FeNi and ordered Ni3Fe are experimentally well established, direct evidence for ordered Fe3Ni is unconvincing. Little experimental data for Fe3Ni exists because diffusion is sluggish at temperatures below 400°C and because alloys containing less than 29 wt% Ni undergo a martensitic transformation at room temperature. Fe-Ni phases in iron meteorites were examined in this study because iron meteorites have cooled at slow rates of about 10°C/106 years, allowing phase transformations below 400°C to occur. One low temperature transformation product, called clear taenite 2 (CT2), was of particular interest because it contains less than 30 wtZ Ni and is not martensitic. Because CT2 is only a few microns in size, the structure and Ni content were determined through electron diffraction and x-ray microanalysis. A Philips EM400T operated at 120 kV, equipped with a Tracor Northern 2000 multichannel analyzer, was used.

Intrinsic n- and p-Type MgZnO Nanorods for Deep-UV Detection and Room-Temperature Gas Sensing

2015 ◽  
Vol 119 (52) ◽  
pp. 29186-29192 ◽  
Author(s):  
Ruey-Chi Wang ◽  
Yu-Xian Lin ◽  
Jia-Jun Wu
Keyword(s):  
Room Temperature ◽  
Gas Sensing ◽  
Uv Detection ◽  
Deep Uv ◽  
P Type

scholarly journals 157-nm pellicles for photolithography: mechanistic investigation of the deep-UV photolysis of fluorocarbons

2004 ◽  
Author(s):  
Kwangjoo Lee ◽  
Steffen Jockusch ◽  
Nicholas J. Turro ◽  
Roger H. French ◽  
Robert C. Wheland ◽  
...  
Keyword(s):  
Uv Photolysis ◽  
Mechanistic Investigation ◽  
Deep Uv

The structural behaviour of the nepheline family: (1) Sr and Ba aluminates (MAl2O4)

1982 ◽  
Vol 45 (337) ◽  
pp. 111-127 ◽  
Author(s):  
C. M. B. Henderson ◽  
D. Taylor
Keyword(s):  
Solid Solutions ◽  
Room Temperature ◽  
Martensitic Transformations ◽  
Hexagonal Symmetry ◽  
Structural Behaviour ◽  
Cell Parameters ◽  
High Transformation ◽  
Temperature Transformation ◽  
Ray Methods ◽  
Expansion Behaviour

AbstractThe structural relations of solid solutions in the series (Sr1−xBax)Al2O4 were studied using room- and high-temperature X-ray methods, infra-red spectroscopy, and DTA. At room temperature, SrAl2O4 and solid solutions with x up to 0.31 are monoclinic, between x = 0.31 and 0.43 monoclinic and hexagonal forms coexist, and between x = 0.43 and 1.0 only hexagonal forms occur. On heating, a member of the monoclinic series of solid solutions transforms to hexagonal symmetry over a range of temperature within which both monoclinic and hexagonal forms coexist. The proportion of the hexagonal form increases instantaneously as the temperature is raised. The transformation temperature decreases with increasing BaAl2O4 in solid solution and, in addition, the temperature width of the region of coexistence is markedly enlarged. SrAl2O4 transforms over the range 665–705 °C and (Sr0.7Ba0.3)Al2O4 over 170–405 °C. The DTA trace for SrAl2O4 shows a peak at 677 °C. On cooling, the transformations show hysteresis of 15 to 25 °C.The coexisting monoclinic and hexagonal forms are believed to be isochemical, and discontinuities in cell parameters occur within the region of coexistence both in the compositional series at room temperature and in the elevated temperature transformation experiments. The low-to-high transformation is accompanied by a volume change of −0.2 to −0.3 %, and is believed to be first-order displacive with additional characteristics similar to those of martensitic transformations.The thermal expansion behaviour of structures in the (Sr,Ba)Al2O4, series indicates that two tilt systems are operative: co-operative rotation of tetrahedra about the c-axis, and tilting of tetrahedra relative to the 0001 plane.The results for the (Sr,Ba)Al2O4 series are shown to be invaluable in reinterpreting the structural behaviour of members of the nepheline and leucite groups of minerals.

scholarly journals The High-Temperature Transformation from 1T- to 3R-LixTiS2 (x = 0.7, 0.9) as Observed in situ with Neutron Powder Diffraction

2015 ◽  
Vol 229 (9) ◽  
Author(s):  
Dennis Wiedemann ◽  
Suliman Nakhal ◽  
Anatoliy Senyshyn ◽  
Thomas Bredow ◽  
Martin Lerch
Keyword(s):  
High Temperature ◽  
Powder Diffraction ◽  
Electrode Material ◽  
Room Temperature ◽  
Lithium Ion ◽  
Neutron Powder Diffraction ◽  
Titanium Disulfide ◽  
Temperature Transformation

AbstractLayered titanium disulfide is used as lithium-ion intercalating electrode material in batteries. The room-temperature stable trigonal 1T polymorphs of the intercalates Li

Optically pumped room temperature low threshold deep UV lasers grown on native AlN substrates

2019 ◽  
Author(s):  
Akhil Raj Kumar Kalapala ◽  
Dong Liu ◽  
Sang June Cho ◽  
Jeongpil Park ◽  
Deyin Zhao ◽  
...  
Keyword(s):  
Room Temperature ◽  
Optically Pumped ◽  
Low Threshold ◽  
Deep Uv ◽  
Uv Lasers

Examination of CaO-Dy2O3 for potential use as a high-temperature transformation toughening System

1988 ◽  
Vol 46 ◽  
pp. 790-791
Author(s):  
M. M. Fleming ◽  
W. M. Kriven
Keyword(s):  
High Temperature ◽  
Room Temperature ◽  
Transformation Toughening ◽  
Stabilized Zirconia ◽  
Two Phase ◽  
Volume Increase ◽  
Partially Stabilized Zirconia ◽  
Temperature Transformation ◽  
Fast Quenching ◽  
Potential Use

Similarities exist between the tetragonal to monoclinic transformation of ZrO2 and the monoclinic (B) to cubic (C) transformation of Dy2O3. On cooling the transformation occurs at 1950°C and is accompanied by an 8 % volume increase which causes shattering of bulk specimens. The transformation can be suppressed, however, by minor additions of CaO. An attempt was made to fabricate a “PSD” analogue to partially stabilized zirconia (PSZ).As-received and chemically precipitated powders of pure Dy2O3 were mixed with CaO (0 to 25 mol%), uniaxially and cold isostatically pressed, sealed in small Mo crucibles and sintered at various temperatures (1900° or 1650°C) and times before cooling or subsequent annealing treatments. Some pellets were annealed in the two phase (B + C) region at 1700°C for 2 hours before quenching. Specimens were examined by XRD, TEM, EDS, HVEM, and STEM.A fast quenching in combination with the =8 mol% CaO additions were found to be essential for retention of the high temperature B phase down to room temperature.

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