Phase change and kinetics of vacuum decomposition of molybdenite concentrate

Vacuum ◽  
2015 ◽  
Vol 116 ◽  
pp. 77-81 ◽  
Author(s):  
Lei Wang ◽  
Peimin Guo ◽  
Jianming Pang ◽  
Lingeng Luo ◽  
Pei Zhao
2003 ◽  
Vol 68 (8) ◽  
pp. 1407-1419 ◽  
Author(s):  
Claudio Fontanesi ◽  
Roberto Andreoli ◽  
Luca Benedetti ◽  
Roberto Giovanardi ◽  
Paolo Ferrarini

The kinetics of the liquid-like → solid-like 2D phase transition of adenine adsorbed at the Hg/aqueous solution interface is studied. Attention is focused on the effect of temperature on the rate of phase change; an increase in temperature is found to cause a decrease of transition rate.


2021 ◽  
Vol 135 ◽  
pp. 106094
Author(s):  
Narges Amini ◽  
Julian Pries ◽  
Yudong Cheng ◽  
Christoph Persch ◽  
Matthias Wuttig ◽  
...  

2016 ◽  
Vol 2016 ◽  
pp. 1-6 ◽  
Author(s):  
Luigi Coppola ◽  
Denny Coffetti ◽  
Sergio Lorenzi

The paper focuses on the evaluation of the rheological and mechanical performances of cement-based renders manufactured with phase-change materials (PCM) in form of microencapsulated paraffin for innovative and ecofriendly residential buildings. Specifically, cement-based renders were manufactured by incorporating different amount of paraffin microcapsules—ranging from 5% to 20% by weight with respect to binder. Specific mass, entrained or entrapped air, and setting time were evaluated on fresh mortars. Compressive strength was measured over time to evaluate the effect of the PCM addition on the hydration kinetics of cement. Drying shrinkage was also evaluated. Experimental results confirmed that the compressive strength decreases as the amount of PCM increases. Furthermore, the higher the PCM content, the higher the drying shrinkage. The results confirm the possibility of manufacturing cement-based renders containing up to 20% by weight of PCM microcapsules with respect to binder.


2006 ◽  
Vol 918 ◽  
Author(s):  
Matthias Wuttig ◽  
Wojciech Welnic ◽  
Ralf Detemple ◽  
Henning Dieker ◽  
Johannes Kalb ◽  
...  

AbstractPhase change materials possess a unique combination of properties which include a pronounced property contrast between the amorphous and crystalline state, i.e. a high electrical and optical contrast. In particular the latter observation is indicative for a considerable structural difference between the amorphous and crystalline state. At the same time the crystallization of the amorphous state proceeds on a fast time scale. This raises the question how structure, properties and kinetics are related in phase change alloys. It will be demonstrated that only a small group of covalent semiconductors with octahedral-like coordination has the required property combination. This is related to their thermodynamic properties which govern the kinetics of crystallization.


2009 ◽  
Vol 92 (5) ◽  
pp. 1079-1086 ◽  
Author(s):  
Triplicane A. Parthasarathy ◽  
Robert A. Rapp ◽  
Mark Opeka ◽  
Ronald J. Kerans

2017 ◽  
Vol 31 (4) ◽  
pp. 4245-4254 ◽  
Author(s):  
Bin Chen ◽  
Feng Xin ◽  
Xiaofei Song ◽  
Xingang Li ◽  
Muhammad Zeshan Azam

2003 ◽  
Vol 22 (6) ◽  
pp. 689-697 ◽  
Author(s):  
D.Z. Chen ◽  
P.S. He ◽  
L.J. Pan

2003 ◽  
Vol 803 ◽  
Author(s):  
Sang Youl Kim

ABSTRACTThe recent research works of optical properties and crystallization kinetics of phase change Ge-Sb-Te-(N) alloy by using ellipsometry are reviewed.The complex refractive index spectra of phase-change Ge2Sb2+xTe5 thin films and those of the nitrogen Ge2Sb2Te5 thin films have been determined.The crystallization behavior of amorphous Ge2Sb2Te5 thin films investigated by in situ ellipsometry revealed that the crystallization process of Ge2Sb2Te5 near 140°C is a two-step process. The kinetic exponent of the Johnson-Mehl-Avrami equation was about 4.4 for the first stage and 1.1 for the second stage. Ex situ study confirmed the cascaded crystallization behavior of phase-change Ge2Sb2Te5 films.A passive type single wavelength ellipsometer adopting a DOAP (division-of-amplitude photopolarimeter) configuration with nanosecond time resolution is developed to monitor the phase transformation of Ge2Sb2Te5 caused by a high power nanosecond laser pulse in real time. The two-step process - the fast nucleation-dominant stage followed by the slow anomalous grain growth stage is confirmed.Based on the recent analysis of the ellipsometric isotherm at moderately elevated temperature, we found for the first time that the fast nucleation dominant crystallization of Ge2Sb2Te 5 can be better explained by a modified JMA equation that illustrates the nucleation dominated process where the creation rate of a new nucleus is proportional to the density of preexisting nuclei and growth rate is negligible.


2011 ◽  
Vol 50 (4R) ◽  
pp. 042601
Author(s):  
Sung-Hsiu Huang ◽  
Yu-Jen Huang ◽  
Hung-Chuan Mai ◽  
Tsung-Eong Hsieh

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