Mesoporous Multicomponent Nanocomposite Colloidal Spheres: Ideal High-Temperature Stable Model Catalysts

2011 ◽  
Vol 50 (16) ◽  
pp. 3725-3729 ◽  
Author(s):  
Chen Chen ◽  
Caiyun Nan ◽  
Dingsheng Wang ◽  
Qiao Su ◽  
Haohong Duan ◽  
...  
Keyword(s):  
High Temperature ◽  
Model Catalysts ◽  
Stable Model ◽  
Colloidal Spheres

Mesoporous Multicomponent Nanocomposite Colloidal Spheres: Ideal High-Temperature Stable Model Catalysts

2011 ◽  
Vol 123 (16) ◽  
pp. 3809-3813 ◽  
Author(s):  
Chen Chen ◽  
Caiyun Nan ◽  
Dingsheng Wang ◽  
Qiao Su ◽  
Haohong Duan ◽  
...  
Keyword(s):  
High Temperature ◽  
Model Catalysts ◽  
Stable Model ◽  
Colloidal Spheres

scholarly journals Pt/ceria thin film model catalysts after high-temperature reduction: a (HR)TEM study

Vacuum ◽  
2003 ◽  
Vol 71 (1-2) ◽  
pp. 71-76 ◽  
Author(s):  
S. Penner ◽  
G. Rupprechter ◽  
H. Sauer ◽  
D.S. Su ◽  
R. Tessadri ◽  
...  
Keyword(s):  
Thin Film ◽  
High Temperature ◽  
Model Catalysts ◽  
Film Model ◽  
Temperature Reduction ◽  
Thin Film Model

Titania-Encapsulated Hybrid Nanocatalysts as Active and Thermally Stable Model Catalysts

2014 ◽  
Vol 145 (3) ◽  
pp. 930-938 ◽  
Author(s):  
Brundabana Naik ◽  
Song Yi Moon ◽  
Sunyoung Oh ◽  
Chan-Ho Jung ◽  
Jeong Young Park
Keyword(s):  
Model Catalysts ◽  
Stable Model ◽  
Thermally Stable

scholarly journals High-temperature Fischer-Tropsch synthesis over FeTi mixed oxide model catalysts: Tailoring activity and stability by varying the Ti/Fe ratio

2017 ◽  
Vol 533 ◽  
pp. 38-48 ◽  
Author(s):  
Vera P. Santos ◽  
Liam Borges ◽  
Sina Sartipi ◽  
Bart van der Linden ◽  
A. Iulian Dugulan ◽  
...  
Keyword(s):  
High Temperature ◽  
Mixed Oxide ◽  
Tropsch Synthesis ◽  
Model Catalysts ◽  
Fischer Tropsch ◽  
Fischer Tropsch Synthesis

XRPD/TEM studies of model high-temperature shift catalysts

2006 ◽  
Vol 39 (4) ◽  
pp. 519-526 ◽  
Author(s):  
Rune E. Johnsen ◽  
Alfons M. Molenbroek ◽  
Kenny Ståhl
Keyword(s):  
High Temperature ◽  
Iron Oxide ◽  
Crystallite Size ◽  
Rietveld Method ◽  
Temperature Shift ◽  
Average Crystallite Size ◽  
Model Catalysts ◽  
Crystallite Sizes ◽  
Scherrer Equation

The combination of transmission electron microscopy (TEM) andin situX-ray powder diffraction (XRPD) for the investigation of four model high-temperature shift catalysts makes it possible to obtain and compare information concerning the crystallite and particle shapes and sizes before, during and after the reduction of the synthesized hematite-based model catalyst to the active magnetite-based catalyst. Two chromium-containing iron oxide model catalysts and two pure iron oxide model catalysts were synthesized from hydrated chloride or nitrate salts, resulting in particles with different shapes and sizes. The average crystallite sizes of four model catalysts were determined by XRPD using the Scherrer equation before and after the reduction. The crystallite sizes determined before the reduction were compared with particles sizes determined from TEM images of the same samples. These sizes were generally in good agreement. By using the Rietveld method combined with the Scherrer equation and the Lorentzian Scherrer broadening parameters, the development of the average crystallite size during thein situreduction was demonstrated. This showed that the average crystallite size of the remaining hematite increases when the reduction begins. Additionally, the average crystallite sizes of the reduced samples showed that the chromium-containing model catalysts have the smallest increase in the overall crystallite size.

High Temperature Stability of Ceria-Zirconia Supported Pd Model Catalysts

1998 ◽  
Author(s):  
Jean-Pierre Cuif ◽  
Steve Deutsch ◽  
Mike Marczi ◽  
Hung-Wen Jen ◽  
George W. Graham ◽  
...  
Keyword(s):  
High Temperature ◽  
Temperature Stability ◽  
Model Catalysts ◽  
High Temperature Stability ◽  
Supported Pd

scholarly journals Pathophysiological Changes in Female Rats with Estrous Cycle Disorder Induced by Long-Term Heat Stress

2020 ◽  
Vol 2020 ◽  
pp. 1-10
Author(s):  
GaiHong An ◽  
XueWei Chen ◽  
Chao Li ◽  
Li Zhang ◽  
MengFan Wei ◽  
...  
Keyword(s):  
Heat Stress ◽  
High Temperature ◽  
Estrous Cycle ◽  
Underlying Mechanism ◽  
Female Rats ◽  
Stable Model ◽  
Sprague Dawley ◽  
Pathological Characteristics ◽  
The Impact

High-temperature exposure is detrimental to women’s reproductive health; however, the impact caused by long-term high temperature is not comprehensive, and a stable model of estrous cycle disorder induced by a high temperature is yet lacking. Herein, we aimed to establish a stable and effective model of estrous cycle disorder in female rats induced by long-term heat stress to study its physiological and pathological characteristics and explore the underlying mechanism. In the present study, female Sprague-Dawley rats with normal estrous cycles were exposed to the temperature of 38±0.5°C, relative humidity (RH) of 55±5% (2 h/d, 1 time/d) hot cabin at more than 90 days. Consequently, after long-term heat stress, no difference was detected in body weight and rectal temperature, but the estrus cycle was prolonged, the uterine organ index was increased, pathological changes occurred, the increase latitude of stress hormones heat shock protein 70 (Hsp70) and corticosterone (CORT) decreased, estradiol (E2) and luteinizing hormone (LH) levels decreased, follicle stimulating hormone (FSH) and prolactin (Prl) levels increased, gonadotropin-releasing hormone (GnRH) and thyroid hormone (T4) showed no difference, and insulin (INS) decreased significantly. Moreover, the mRNA expression of the sex hormone receptor in the uterus and ovary was altered. Therefore, the estrous cycle disorder in female rats can be induced by regular heat stress for 90 days, which can be considered the pioneer method. Subsequently, prominent physiological and pathological characteristics and disruption in the hypothalamic-pituitary-gonadal (HPG) axis were noted.

Influence of Thermo-Mechanical Processing on the Microstructure of Beryllia Dispersed Nickel Alloys

1973 ◽  
Vol 31 ◽  
pp. 184-185
Author(s):  
M.S. Grewal ◽  
S.A. Sastri ◽  
N.J. Grant
Keyword(s):  
High Temperature ◽  
Nickel Alloys ◽  
Thermomechanical Processing ◽  
Cold Work ◽  
High Temperature Strength ◽  
Strengthening Effect ◽  
Mechanical Processing ◽  
Uniform Dispersion ◽  
Oxide Particles ◽  
Nickel Base

Currently there is a great interest in developing nickel base alloys with fine and uniform dispersion of stable oxide particles, for high temperature applications. It is well known that the high temperature strength and stability of an oxide dispersed alloy can be greatly improved by appropriate thermomechanical processing, but the mechanism of this strengthening effect is not well understood. This investigation was undertaken to study the dislocation substructures formed in beryllia dispersed nickel alloys as a function of cold work both with and without intermediate anneals. Two alloys, one Ni-lv/oBeo and other Ni-4.5Mo-30Co-2v/oBeo were investigated. The influence of the substructures produced by Thermo-Mechanical Processing (TMP) on the high temperature creep properties of these alloys was also evaluated.

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