New method of controlling structural changes in glass-crystalline materials

1964 ◽  
Vol 21 (3) ◽  
pp. 131-133 ◽  
Author(s):  
A. F. Borisov ◽  
V. I. Zadumin
Keyword(s):  
Structural Changes ◽  
New Method ◽  
Crystalline Materials

Site-specific incorporation of multiple units of functional nucleotides into DNA using a step-wise approach with polymerase and its application to monitoring DNA structural changes

2019 ◽  
Vol 55 (15) ◽  
pp. 2158-2161 ◽  
Author(s):  
Binh Huy Le ◽  
Van Thang Nguyen ◽  
Young Jun Seo
Keyword(s):  
Secondary Structure ◽  
Structural Changes ◽  
New Method ◽  
Site Specific ◽  
Structure Dynamics ◽  
Hairpin Secondary Structure ◽  
Multiple Units

We have developed a new method, a step-wise approach with polymerase, for site-specific incorporation of multiple units of functional nucleotides into DNA for monitoring hairpin secondary structure dynamics.

The Measurement of Thermally Induced Structural Changes by High Temperature (900°C) Guinier X-Ray Powder Diffraction Techniques

1982 ◽  
Vol 26 ◽  
pp. 171-180 ◽  
Author(s):  
T. G. Fawcett ◽  
P. Moore Kirchhoff ◽  
R. A. Newman
Keyword(s):  
High Temperature ◽  
Structural Transformation ◽  
Powder Diffraction ◽  
Structural Changes ◽  
New Method ◽  
Internal Standards ◽  
Thermally Induced ◽  
X Ray

AbstractA new method for the collection and analysis of high temperature Guinier x-ray data has been devised at The Dow Chemical Co. This technique can be used to monitor various types of structural transformation and thermal expansions up to 900°C. The thermal expansions of α-Al2O3 and two TiO2 structures, anatase and rutile, have been characterized for their use as high temperature internal standards.

scholarly journals Nanoscale strength distribution in amorphous versus crystalline metals

2010 ◽  
Vol 25 (12) ◽  
pp. 2251-2263 ◽  
Author(s):  
C.E. Packard ◽  
O. Franke ◽  
E.R. Homer ◽  
C.A. Schuh
Keyword(s):  
Yield Point ◽  
Metallic Glasses ◽  
Structural Changes ◽  
Thermal Fluctuations ◽  
Strength Distribution ◽  
Future Research ◽  
Transformation Zone ◽  
Crystalline Materials ◽  
Plastic Yield

Low-load nanoindentation can be used to assess not only the plastic yield point, but the distribution of yield points in a material. This paper reviews measurements of the so-called nanoscale strength distribution (NSD) on two classes of materials: crystals and metallic glasses. In each case, the yield point has a significant spread (10–50% of the mean normalized stress), but the origins of the distribution are shown to be very different in the two materials classes. In crystalline materials the NSD can arise from thermal fluctuations and is attended by significant rate and temperature dependence. In metallic glasses well below their glass-transition temperature, the NSD is reflective of fluctuations in the sampled structure and is not very sensitive to rate or temperature. Computer simulations using shear transformation zone dynamics are used to separate the effects of thermal and structural fluctuations in metallic glasses, and support the latter as dominating the NSD of those materials at low temperatures. Finally, the role of the NSD as a window on structural changes due to annealing or prior deformation is discussed as a direction for future research on metallic glasses in particular.

Photoinduced structural dynamics of polar solids studied by femtosecond X-ray diffraction

2010 ◽  
Vol 66 (2) ◽  
pp. 168-178 ◽  
Author(s):  
Thomas Elsaesser ◽  
Michael Woerner
Keyword(s):  
Real Time ◽  
Structural Changes ◽  
Bragg Diffraction ◽  
X Ray Diffraction ◽  
Crystalline Materials ◽  
X Ray ◽  
Density Maps ◽  
Diffraction Patterns ◽  
Superlattice Structures ◽  
Work Done

Femtosecond X-ray diffraction allows for real-time mapping of structural changes in condensed matter on atomic length and timescales. Sequences of diffraction patterns provide both transient geometries and charge-density maps of crystalline materials. This article reviews recent progress in this field, the main emphasis being on experimental work done with laser-driven hard X-ray sources. Both Bragg diffraction techniques for bulk and nanostructured single crystals as well as the recently implemented powder diffraction from polycrystalline samples are discussed. In ferroelectric superlattice structures, coherent phonon motions and the driving stress mechanisms are observed in real time. In molecular crystals charge-transfer processes and the concomitant changes of the lattice geometry are analyzed.

scholarly journals Chiral Conducting Me-EDT-TTF and Et-EDT-TTF-Based Radical Cation Salts with the Perchlorate Anion

Crystals ◽  
2020 ◽  
Vol 10 (11) ◽  
pp. 1069
Author(s):  
Nabil Mroweh ◽  
Pascale Auban-Senzier ◽  
Nicolas Vanthuyne ◽  
Elsa B. Lopes ◽  
Manuel Almeida ◽  
...  
Keyword(s):  
Radical Cation ◽  
Structural Changes ◽  
Crystal Packing ◽  
Tight Binding ◽  
Molecular Conductors ◽  
Temperature Conductivity ◽  
Room Temperature Conductivity ◽  
Crystalline Materials ◽  
Metallic Conductivity ◽  
Radical Cation Salts

Introduction of chirality in the field of molecular conductors has received increasing interest in recent years in the frame of modulation of the crystal packing, and hence conducting properties, with the number of stereogenic centers and absolute configuration, e.g., racemic or enantiopure forms. Here, we describe the preparation by electrocrystallization of chiral radical cation salts, based on the donors methyl-ethylenedithio-tetrathiafulvalene (Me-EDT-TTF) 1 and ethyl-ethylenedithio-tetrathiafulvalene (Et-EDT-TTF) 2 containing one stereogenic center, with the perchlorate anion. Donor 1 provided the series of crystalline materials [(rac)-1]ClO4, [(S)-1]2ClO4 and [(R)-1]2ClO4, while for donor 2 only the 1:1 salts [(rac)-2]ClO4 and [(R)-2]ClO4 could be prepared as suitable single crystals for X-ray analysis. The enantiopure salts of 1 show β-type packing and metallic conductivity in the high temperature regime, with room temperature conductivity values of 5–10 S cm−1, whereas compound [(rac)-2]ClO4 is a very poor semiconductor. Tight-binding extended Hückel band structure calculations support the metallic conductivity of the enantiopure salts of 1 and suggest that small structural changes, possibly induced by thermal contraction or pressure, could lead to a pseudo-elliptic closed Fermi surface, typical for a 2D metal.

X-ray induced structural changes in organic and biological crystalline materials

2007 ◽  
Vol 63 (a1) ◽  
pp. s282-s282
Author(s):  
F. Camus ◽  
C. Besnard ◽  
A. Dahlström ◽  
I. Margiolaki ◽  
P. Pattison ◽  
...  
Keyword(s):  
Structural Changes ◽  
Crystalline Materials ◽  
X Ray
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