Understanding cellulose pyrolysis under hydrogen atmosphere

2022 ◽  
Vol 254 ◽  
pp. 115195
Author(s):  
Tan Li ◽  
Kai Miao ◽  
Zhigang Zhao ◽  
Yuqing Li ◽  
Huiyuan Wang ◽  
...  
Keyword(s):  
Hydrogen Atmosphere ◽  
Cellulose Pyrolysis

Diffusion model for deposition of epitaxial GaAs layers prepared by the MOCVD method

1991 ◽  
Vol 56 (10) ◽  
pp. 2020-2029
Author(s):  
Jindřich Leitner ◽  
Petr Voňka ◽  
Josef Stejskal ◽  
Přemysl Klíma ◽  
Rudolf Hladina
Keyword(s):  
Experimental Data ◽  
Growth Rate ◽  
Kinetic Model ◽  
Gas Phase ◽  
Substrate Surface ◽  
Deposition Process ◽  
Hydrogen Atmosphere ◽  
Epitaxial Gaas ◽  
Kinetics Of ◽  
Good Agreement

The authors proposed and treated quantitatively a kinetic model for deposition of epitaxial GaAs layers prepared by reaction of trimethylgallium with arsine in hydrogen atmosphere. The transport of gallium to the surface of the substrate is considered as the controlling process. The influence of the rate of chemical reactions in the gas phase and on the substrate surface on the kinetics of the deposition process is neglected. The calculated dependence of the growth rate of the layers on the conditions of the deposition is in a good agreement with experimental data in the temperature range from 600 to 800°C.

Structural reconstruction of germanosilicate frameworks by controlled hydrogen reduction

2019 ◽  
Vol 55 (13) ◽  
pp. 1883-1886 ◽  
Author(s):  
Yue Ma ◽  
Hao Xu ◽  
Xue Liu ◽  
Mingming Peng ◽  
Wenting Mao ◽  
...  
Keyword(s):  
Metal Clusters ◽  
Hydrogen Reduction ◽  
Hydrogen Atmosphere ◽  
Water Washing

Calcined UTL-type germanosilicate was firstly reduced in a hydrogen atmosphere at an appropriate temperature. Then, air-calcination and water-washing procedures were performed to remove the Ge metal clusters or crystals originated from the reduction of skeleton germanium(iv) to yield pure zeolite phase of two daughter structures analogous to IPC-2 and IPC-6.

Low-Temperature Post-Oxidation Annealing Using Atomic Hydrogen Radicals Generated by High-Temperature Catalyzer for Improvement in Reliability of Thermal Oxides on 4H-SiC

2006 ◽  
Vol 527-529 ◽  
pp. 999-1002
Author(s):  
Junji Senzaki ◽  
Atsushi Shimozato ◽  
Kenji Fukuda
Keyword(s):  
High Temperature ◽  
Low Temperature ◽  
Atomic Hydrogen ◽  
High Reliability ◽  
Hydrogen Atmosphere ◽  
Exposed Sample ◽  
New Apparatus ◽  
Hydrogen Radical ◽  
Hydrogen Radicals ◽  
Sic Wafer

Low-temperature post-oxidation annealing (POA) process of high-reliability thermal oxides grown on 4H-SiC using new apparatus that generates atomic hydrogen radicals by high-temperature catalyzer has been investigated. Atomic hydrogen radicals were generated by thermal decomposition of H2 gas at the catalyzer surface heated at high temperature of 1800°C, and then exposed to the sample at 500°C in reactor pressure of 20 Pa. The mode and maximum values of field-to-breakdown are 11.0 and 11.2 MV/cm, respectively, for the atomic hydrogen radical exposed sample. In addition, the charge-to-breakdown at 63% cumulative failure of the thermal oxides for atomic hydrogen radical exposed sample was 0.51 C/cm2, which was higher than that annealed at 800°C in hydrogen atmosphere (0.39 C/cm2). Consequently, the atomic hydrogen radical exposure at 500°C has remarkably improved the reliability of thermal oxides on 4H-SiC wafer, and is the same effect with high-temperature hydrogen POA at 800°C.

scholarly journals Robust and efficient hydrogenation of carbonyl compounds catalysed by mixed donor Mn(I) pincer complexes

2021 ◽  
Vol 12 (1) ◽  
Author(s):  
Wenjun Yang ◽  
Ivan Yu. Chernyshov ◽  
Robin K. A. van Schendel ◽  
Manuela Weber ◽  
Christian Müller ◽  
...  
Keyword(s):  
Noble Metal ◽  
Crucial Role ◽  
Carbonyl Compounds ◽  
Catalytic Performance ◽  
Hydrogen Atmosphere ◽  
Pincer Complexes ◽  
Catalyst Activation ◽  
Hydrogenation Catalysts ◽  
Induction Times

AbstractAny catalyst should be efficient and stable to be implemented in practice. This requirement is particularly valid for manganese hydrogenation catalysts. While representing a more sustainable alternative to conventional noble metal-based systems, manganese hydrogenation catalysts are prone to degrade under catalytic conditions once operation temperatures are high. Herein, we report a highly efficient Mn(I)-CNP pre-catalyst which gives rise to the excellent productivity (TOF° up to 41 000 h−1) and stability (TON up to 200 000) in hydrogenation catalysis. This system enables near-quantitative hydrogenation of ketones, imines, aldehydes and formate esters at the catalyst loadings as low as 5–200 p.p.m. Our analysis points to the crucial role of the catalyst activation step for the catalytic performance and stability of the system. While conventional activation employing alkoxide bases can ultimately provide catalytically competent species under hydrogen atmosphere, activation of Mn(I) pre-catalyst with hydride donor promoters, e.g. KHBEt3, dramatically improves catalytic performance of the system and eliminates induction times associated with slow catalyst activation.

scholarly journals GJ 436b and the stellar wind interaction: simulations constraints using Lyα and Hα transits

2020 ◽  
Author(s):  
Carolina Villarreal D’Angelo ◽  
Aline A Vidotto ◽  
Alejandro Esquivel ◽  
Gopal Hazra ◽  
Allison Youngblood
Keyword(s):  
Mass Loss ◽  
Stellar Wind ◽  
Planetary System ◽  
Neutral Hydrogen ◽  
Hydrogen Atmosphere ◽  
Planetary Atmosphere ◽  
Hydrodynamic Simulations ◽  
Stellar Disc ◽  
Planetary Mass ◽  
Best Fit

Abstract The GJ 436 planetary system is an extraordinary system. The Neptune-size planet that orbits the M3 dwarf revealed in the Lyα line an extended neutral hydrogen atmosphere. This material fills a comet-like tail that obscures the stellar disc for more than 10 hours after the planetary transit. Here, we carry out a series of 3D radiation hydrodynamic simulations to model the interaction of the stellar wind with the escaping planetary atmosphere. With these models, we seek to reproduce the $\sim 56\%$ absorption found in Lyα transits, simultaneously with the lack of absorption in Hα transit. Varying the stellar wind strength and the EUV stellar luminosity, we search for a set of parameters that best fit the observational data. Based on Lyα observations, we found a stellar wind velocity at the position of the planet to be around [250-460] km s−1 with a temperature of [3 − 4] × 105 K. The stellar and planetary mass loss rates are found to be 2 × 10−15 M⊙ yr−1 and ∼[6 − 10] × 109 g s−1, respectively, for a stellar EUV luminosity of [0.8 − 1.6] × 1027 erg s−1. For the parameters explored in our simulations, none of our models present any significant absorption in the Hα line in agreement with the observations.

scholarly journals DEPOSITION AND CHARACTERISATION OF SPUTTERED MOLYBDENUM OXIDE THIN FILMS WITH HYDROGEN ATMOSPHERE

2021 ◽  
pp. 150285
Author(s):  
Nicolau Lopez-Pinto ◽  
Thomas Tom ◽  
Joan Bertomeu ◽  
Jose Miguel Asensi ◽  
Eloi Ros ◽  
...  
Keyword(s):  
Thin Films ◽  
Molybdenum Oxide ◽  
Hydrogen Atmosphere ◽  
Oxide Thin Films

Preparation and Performance of Ni-YSZ/YSZ Co-Ceramic Using Multiple Gel-Tape Casting

2012 ◽  
Vol 512-515 ◽  
pp. 1555-1558
Author(s):  
Zhong Zhou Yi ◽  
Feng Rui Zhai ◽  
Hong Tian ◽  
Zhi Peng Xie
Keyword(s):  
Expansion Coefficient ◽  
Tape Casting ◽  
Composite Ceramic ◽  
Hydrogen Atmosphere ◽  
Intermediate Temperature ◽  
Layer Composite ◽  
Ceramic Disk ◽  
Sem Micrograph ◽  
And Performance ◽  
Fuel Cell Anode

Use starch, corn meal and activated carbon as pore-making agent, Ni-YSZ/YSZ composite ceramic green body was prepared by multiple gel-tape casting with acryloyl ammonium-polyvinyl alcohol. The specimen was sintered at 1450°C for 4h, then reduced in hydrogen atmosphere at 800°C for 4h, Ni-YSZ/YSZ composite ceramic disk was obtained, the porosity, thermal expansion coefficient, electrical properties and microstructures of the specimen was tested. The results showed that the porosity of Ni-YSZ/YSZ composite ceramic disk reaches about 30% when use starch as pore-making agent, expansion coefficient is proportional to porosity, both of them reduced with the temperature increased. The YSZ is continued and compact with network structure, Ni particulates are well distributed in it, suitable for intermediate temperature solid oxide fuel cell anode materials. Image analysis of SEM micrograph showed that the structure is loose, porous, uniform and compact in Ni/YSZ/YSZ multi-layer composite ceramics, which meet the requirement of intermediate temperature SOFC.

Synthesis of high-purity Li8ZrO6 powder by solid state reaction under hydrogen atmosphere

2016 ◽  
Vol 109-111 ◽  
pp. 1739-1743 ◽  
Author(s):  
Kiyoto Shin-mura ◽  
Yu Otani ◽  
Seiya Ogawa ◽  
Eiki Niwa ◽  
Takuya Hashimoto ◽  
...  
Keyword(s):  
Solid State ◽  
High Purity ◽  
Solid State Reaction ◽  
Hydrogen Atmosphere
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