Calcite nucleation on the surface of PNIPAM–PAAc micelles studied by time resolved in situ PXRD

CrystEngComm ◽  
2015 ◽  
Vol 17 (36) ◽  
pp. 6940-6946 ◽  
Author(s):  
Anders C. S. Jensen ◽  
Mogens Hinge ◽  
Henrik Birkedal

Nanocrystalline calcite is formed under the influence of block copolymers containing thermoresponsive PNIPAM and a mineralization controlling block of poly(acrylic acid) and the nanocrystal formation kinetics studied by in situ X-ray diffraction.

1994 ◽  
Vol 9 (2) ◽  
pp. 275-285 ◽  
Author(s):  
V. Milonopoulou ◽  
K.M. Forster ◽  
J.P. Formica ◽  
J. Kulik ◽  
J.T. Richardson ◽  
...  

The YBa2Cu3O7−x formation kinetics from a spray-roasted precursor powder containing Y2O3, BaCO3, and CuO was followed via in situ, time-resolved x-ray diffraction as a function of gas atmosphere and temperature. In inert atmospheres, BaCO3 and CuO form BaCu2O2 which subsequently reacts with Y2O3 to form YBa2Cu3O6. However, YBa2Cu3O6 decomposes at temperatures exceeding 725 °C with Y2BaCuO5 being one of the decomposition products. In oxidizing atmospheres, YBa2Cu3O7−x formation involves the BaCuO2. At high temperatures (800–840 °C), oxygen increases the yield of YBa2Cu3O6. A nuclei growth model assuming two-dimensional, diffusion-controlled growth with second-order nucleation rate fits the experimental data.


Carbon ◽  
2015 ◽  
Vol 87 ◽  
pp. 246-256 ◽  
Author(s):  
Périne Landois ◽  
Mathieu Pinault ◽  
Stéphan Rouzière ◽  
Dominique Porterat ◽  
Cristian Mocuta ◽  
...  

2017 ◽  
Vol 111 (8) ◽  
pp. 082907 ◽  
Author(s):  
Seiji Nakashima ◽  
Osami Sakata ◽  
Hiroshi Funakubo ◽  
Takao Shimizu ◽  
Daichi Ichinose ◽  
...  

2008 ◽  
Vol 72 (1) ◽  
pp. 201-204 ◽  
Author(s):  
A. Sumoondur ◽  
S. Shaw ◽  
I. Ahmed ◽  
L. G. Benning

AbstractIn this study, direct evidence for the formation of magnetite via a green rust intermediate is reported. The Fe(II) induced transformation of ferrihydrite, was quantified in situ and under O2-free conditions using synchrotron-based time-resolved energy dispersive X-ray diffraction. At pH 9 and Fe(II)/Fe(III) ratios of 0.5 and 1, rapid growth (6 min) of sulphate green rust and its subsequent transformation to magnetite was observed. Electron microscopy confirmed these results, showing the initial rapid formation of hexagonal sulphate green rust particles, followed by the corrosion of the green rust as magnetite growth occurred, indicating that the reaction proceeds via a dissolution-reprecipitation mechanism. At pH 7 and Fe(II)/Fe(III) ratio of 0.5, sulphate green rust was the stable phase, with no transformation to magnetite.


1998 ◽  
Vol 21 (4-6) ◽  
pp. 253-262 ◽  
Author(s):  
Dermot O'Hare ◽  
John S.O. Evans ◽  
Robin J. Francis ◽  
P. Shiv Halasyamani ◽  
Poul Norby ◽  
...  

2020 ◽  
Author(s):  
Bikash Garai ◽  
Volodymyr Bon ◽  
Francesco Walenszus ◽  
Azat Khadiev ◽  
Dmitri Novikov ◽  
...  

Variation in the metal centres of M-M paddle-wheel SBU results in the formation of isostructural DUT-49(M) frameworks. However, the porosity of the framework was found to be different for each of the structures. While a high and moderate porosity was obtained for DUT-49(Cu) and DUT-49(Ni), respectively, other members of the series [DUT-49(M); M= Mn, Fe, Co, Zn, Cd] show very low porosity and shapes of the adsorption isotherms which is not expected for op phases of these MOFs. Investigation on those MOFs revealed that those frameworks undergo structural collapse during the solvent removal at the activation step. Thus, herein, we aimed to study the detailed structural transformations that are possibly occurring during the removal of the subcritical fluid from the framework.


2005 ◽  
Vol 37 (1) ◽  
pp. 27-34 ◽  
Author(s):  
S. Paris ◽  
E. Gaffet ◽  
D. Vrel ◽  
D. Thiaudiere ◽  
M. Gailhanou ◽  
...  

The control of Mechanically Activated Field Activated Pressure Assisted Synthesis hereafter called the MAFAPAS process is the main objective to be achieved for producing nanostructure materials with a controlled consolidation level. Consequently, it was essential to develop characterization tools "in situ" such as the Time Resolved X-ray Diffraction (TRXRD), with an X-ray synchrotron beam (H10, LURE Orsay) coupled to an infrared thermography to study simultaneously structural transformations and thermal evolutions. From the 2003 experiments, we took the opportunity to modify the sample-holder in order to reproduce the better synthesis conditions of the MAFAPAS process, but without the consolidation step. The versatility of the setup has been proved and could even be enhanced by the design of new sample holders. In addition, this work clearly shows that this equipment will allow, on the one hand, to make progress of the understanding of MAFAPAS mechanisms and, on the other hand, to adjust reaction parameters (mechanical activation and combustion synthesis) for producing many materials with an expected microstructure.


2013 ◽  
Vol 117 (8) ◽  
pp. 3915-3922 ◽  
Author(s):  
Xianqin Wang ◽  
Jonathan C. Hanson ◽  
Ja Hun Kwak ◽  
Janos Szanyi ◽  
Charles H. F. Peden

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