scholarly journals Direct measurement of X-ray induced heating of microcrystals

2019 ◽  
Author(s):  
Anna J Warren ◽  
Danny Axford ◽  
Robin L Owen
Keyword(s):  
Glass Transition ◽  
Transition Temperature ◽  
Glass Transition Temperature ◽  
Temperature Control ◽  
Macromolecular Crystallography ◽  
Temperature Dependent ◽  
Temperature Changes ◽  
X Ray ◽  
Dose Rates ◽  
Validation Tool

AbstractTemperature control is a key aspect of macromolecular crystallography, with the technique of cryocooling routinely used to mitigate X-ray induced damage. Beam induced heating could cause the temperature of crystals to rise above the glass transition temperature, greatly increasing the rate of damage. X-ray induced heating of ruby crystals 20-40 microns in size has been quantified non-invasively by monitoring the emission wavelengths of X-ray induced fluorescence during exposure to the X-ray beam. For beamsizes and dose-rates typically used in macromolecular crystallography the temperature rises are of order 20 K. The temperature changes observed are compared with models in the literature and can be used as a validation tool for future models.SynopsisX-ray induced heating of micro-crystals is quantified through the temperature-dependent shift in X-ray induced fluorescence from ruby crystals.

scholarly journals Direct measurement of X-ray-induced heating of microcrystals

2019 ◽  
Vol 26 (4) ◽  
pp. 991-997 ◽  
Author(s):  
Anna J. Warren ◽  
Danny Axford ◽  
Robin L. Owen
Keyword(s):  
Glass Transition ◽  
Transition Temperature ◽  
Glass Transition Temperature ◽  
Direct Measurement ◽  
Temperature Control ◽  
Macromolecular Crystallography ◽  
Temperature Changes ◽  
X Ray ◽  
Dose Rates ◽  
Validation Tool

Temperature control is a key aspect of macromolecular crystallography, with the technique of cryocooling routinely being used to mitigate X-ray-induced damage. Beam-induced heating could cause the temperature of crystals to rise above the glass transition temperature, greatly increasing the rate of damage. X-ray-induced heating of ruby crystals of 20–40 µm in size has been quantified non-invasively by monitoring the emission wavelengths of X-ray-induced fluorescence during exposure to the X-ray beam. For the beam sizes and dose rates typically used in macromolecular crystallography, the temperature rises are of the order of 20 K. The temperature changes observed are compared with models in the literature and can be used as a validation tool for future models.

Glass transition temperature control by poly(norbornene-dicarboximide) copolymers

2014 ◽  
Vol 72 (3) ◽  
pp. 503-521 ◽  
Author(s):  
Andrew M. Spring ◽  
Daisuke Maeda ◽  
Masaaki Ozawa ◽  
Keisuke Odoi ◽  
Feng Qiu ◽  
...  
Keyword(s):  
Glass Transition ◽  
Transition Temperature ◽  
Glass Transition Temperature ◽  
Temperature Control

scholarly journals Determination of glass transition temperature using temperature dependent signal from a cryogenic photopyroelectric instrument

2019 ◽  
Vol 676 ◽  
pp. 7-12 ◽  
Author(s):  
Allen Mathew ◽  
Fabrice Goutier ◽  
Benoit Escorne ◽  
Abdelaziz Elass ◽  
Gérard Louis ◽  
...  
Keyword(s):  
Glass Transition ◽  
Transition Temperature ◽  
Glass Transition Temperature ◽  
Temperature Dependent ◽  
Dependent Signal

PREPARATION AND PROPERTIES OF A NOVEL EPOXIDIZED CASTOR OIL/CLAY NANOCOMPOSITES

2004 ◽  
Vol 03 (04n05) ◽  
pp. 663-669 ◽  
Author(s):  
S.-J. PARK ◽  
F.-L. JIN ◽  
J.-R. LEE
Keyword(s):  
Glass Transition ◽  
Transition Temperature ◽  
Glass Transition Temperature ◽  
Mechanical Analysis ◽  
Clay Nanocomposites ◽  
X Ray Diffraction ◽  
X Ray ◽  
Tearing Energy ◽  
And Storage ◽  
Epoxidized Castor Oil

A novel nanocomposites of modified clay in a glassy epoxy were prepared using a direct melt intercalation technique. The contents of oganoclay were varied with 0, 1, 2, and 3 wt% and N-benzylpyrazinium hexafluoroantimonate (BPH) was used for curing of epoxy matrix as a cationic latent catalyst. Dynamic mechanical analysis (DMA) measurement was performed to examine the glass transition temperature of the nanocomposites. As a result, X-ray diffraction indicated the intercalation of the epoxy chains happening inside the gallery of clay. The nanocomposites showed a higher glass transition temperature and storage modulus than those of the pristine epoxy. The mechanical interfacial properties of the nanocomposites were also investigated and the improvement in tearing energy of 160% over pristine epoxy was obtained.

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