Structural Determination of the Symmetry-Breaking Parameter intrans-(CH)x

1982 ◽  
Vol 48 (2) ◽  
pp. 100-104 ◽  
Author(s):  
C. R. Fincher ◽  
C. -E. Chen ◽  
A. J. Heeger ◽  
A. G. MacDiarmid ◽  
J. B. Hastings
Keyword(s):  
Symmetry Breaking ◽  
Structural Determination ◽  
Breaking Parameter

Symmetry breaking in convergent-beam diffraction

1989 ◽  
Vol 47 ◽  
pp. 480-481
Author(s):  
D.J. Eaglesham
Keyword(s):  
Symmetry Breaking ◽  
Point Group ◽  
X Ray Diffraction ◽  
Multiple Diffraction ◽  
Space Groups ◽  
Atomic Displacements ◽  
Small Probe ◽  
Phase Sensitive ◽  
Convergent Beam

Convergent Beam Electron Diffraction is now almost routinely used in the determination of the point- and space-groups of crystalline samples. In addition to its small-probe capability, CBED is also postulated to be more sensitive than X-ray diffraction in determining crystal symmetries. Multiple diffraction is phase-sensitive, so that the distinction between centro- and non-centro-symmetric space groups should be trivial in CBED: in addition, the stronger scattering of electrons may give a general increase in sensitivity to small atomic displacements. However, the sensitivity of CBED symmetry to the crystal point group has rarely been quantified, and CBED is also subject to symmetry-breaking due to local strains and inhomogeneities. The purpose of this paper is to classify the various types of symmetry-breaking, present calculations of the sensitivity, and illustrate symmetry-breaking by surface strains.CBED symmetry determinations usually proceed by determining the diffraction group along various zone axes, and hence finding the point group. The diffraction group can be found using either the intensity distribution in the discs

Structural Determination of Certain Novel ER Complexes

2004 ◽  
Author(s):  
Ya-Ling Wu ◽  
Geoffrey L. Greene
Keyword(s):  
Structural Determination

Phytochemical Constituents of Annona reticulata and their Cytotoxic Activity

2020 ◽  
Vol 17 (3) ◽  
pp. 206-210
Author(s):  
Ty Viet Pham ◽  
Thang Quoc Le ◽  
Anh Tuan Le ◽  
Hung Quoc Vo ◽  
Duc Viet Ho
Keyword(s):  
Cytotoxic Activity ◽  
Cell Lines ◽  
Structural Determination ◽  
Phytochemical Investigation ◽  
Ic50 Values ◽  
Phytochemical Constituents ◽  
First Time ◽  
Annona Reticulata

A phytochemical investigation of the leaves of Annona reticulata led to the isolation and structural determination of β-sitosterol (1), ent-pimara-8(14),15-dien-19-oic acid (2), ent-pimara- 8(14),15-dien-19-ol (3), quercetin (4), quercetin 3-O-α-L-arabinopyranoside (5), and a mixture of quercetin 3-O-β-D-galactopyranoside (6a) and quercetin 3-O-β-D-glucopyranoside (6b). Of these, compounds 2 and 3 were isolated from the genus Annona for the first time. Compound 3 showed strong cytotoxicity against SK-LU-1 and SW626 cell lines with IC50 values of 17.64 ± 1.07 and 19.79 ± 1.41 μg mL-1, respectively.

Structural Determination of the Hydrofullerene C60D36 by Neutron Diffraction

1998 ◽  
Vol 54 (3) ◽  
pp. 345-350 ◽  
Author(s):  
L. E. Hall ◽  
D. R. McKenzie ◽  
R. L. Davis ◽  
M. I. Attalla ◽  
A. M. Vassallo
Keyword(s):  
Neutron Diffraction ◽  
Density Function ◽  
Diffraction Data ◽  
Fourier Transformation ◽  
Structural Determination ◽  
Molecular Models ◽  
Reduced Density ◽  
C Nmr

A mixture of C60D36 with 24.5 \pm 4.5% C60 by weight has been analysed by neutron diffraction techniques. The diffraction data was converted to a reduced density function G(r) by Fourier transformation. The C60 component of the G(r) was subtracted out. This enabled a comparison for five molecular models of C60D36, with symmetries T, Th , S 6 and two D 3 d isomers, with the experimental G(r). This specimen of C60D36 was found to be best described by a T symmetry isomer, in agreement with 13C NMR and IR data for C60H36 [Attalla et al. (1993). J. Phys. Chem. pp. 6329–6331].

Structural Determination of High Density, ATRP Grown Polystyrene Brushes by Neutron Reflectivity

2009 ◽  
Vol 42 (24) ◽  
pp. 9523-9527 ◽  
Author(s):  
John R. Ell ◽  
Dennis E. Mulder ◽  
Roland Faller ◽  
Timothy E. Patten ◽  
Tonya L. Kuhl
Keyword(s):  
High Density ◽  
Neutron Reflectivity ◽  
Structural Determination

Structural Determination of a Metastable Ag27 Nanocluster and Its Transformations into Ag8 and Ag29 Nanoclusters

2021 ◽  
Author(s):  
Chen Zhu ◽  
Tenfei Duan ◽  
Hao Li ◽  
Xiao Wei ◽  
Xi Kang ◽  
...  
Keyword(s):  
Structure Determination ◽  
Structural Determination ◽  
To Receive

Research on nanocluster transformation has generally focused on stable nanoclusters, while analysis on structure evolutions of metastable nanoclusters just began to receive attention recently. Herein, we reported the structure determination...

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