Acta Crystallographica Section A

Foundations of Crystallography

Volume 67, Part 6 (November 2011)



[Issue Author Index][Volume Author Index]
[Cover illustration] Cover illustration: Polar mode GM6 (left) and antiferrodistortive mode M3-1q (right) present in the monoclinic structure of SrAl2O4, together with a graph of maximal subgroups showing their isotropy subgroups. The amplitude of mode GM6 is much larger, and ab initio calculations confirm its soft character, while distortion M3-1q is a hard mode frozen as an induced secondary distortion [Perez-Mato et al. (2010). Acta Cryst. A66, 558-590]. The mode figures were drawn using FullProf Studio [Rodriguez-Carvajal (1993). Physica B, 192, 55-69].

research papers


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Acta Cryst. (2011). A67, 491-506  [ doi:10.1107/S0108767311029825 ]

A Fourier transform method for powder diffraction based on the Debye scattering equation

N. W. Thomas

Synopsis: A novel fast Fourier transform method is described for calculating powder diffraction patterns from crystal structural data. By also taking the Patterson symmetry of crystal structures into account, computational times can be reduced by an order of magnitude, thereby facilitating the application of the Debye scattering equation to microcrystallites.

Online 13 October 2011


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Acta Cryst. (2011). A67, 507-511  [ doi:10.1107/S0108767311034039 ]

Structure of ice Ih and ice Ic as described in the language of Delaunay simplices

Y. I. Naberukhin and V. P. Voloshin

Synopsis: A full classification of the Delaunay simplex forms has been performed which involve the structure of ice Ih and ice Ic.

Online 13 October 2011


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Acta Cryst. (2011). A67, 512-516  [ doi:10.1107/S0108767311034350 ]

Some Beq are more equivalent than others

E. A. Merritt

Synopsis: Beq is a well defined entity that represents one property, mean-square displacement, of the anisotropic atomic displacement parameter tensor from which it is derived. Beq is not, however, the best estimate of the B factor that would result from isotropic model refinement. A new entity Best is proposed to serve this purpose.

Online 13 October 2011


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Acta Cryst. (2011). A67, 517-520  [ doi:10.1107/S0108767311035513 ]

Form, symmetry and packing of biomacromolecules. IV. Filled capsids of cowpea, tobacco, MS2 and pariacoto RNA viruses

A. Janner

Synopsis: The molecular crystallographic properties of four RNA viruses are discussed.

Online 13 October 2011


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Acta Cryst. (2011). A67, 521-532  [ doi:10.1107/S010876731103577X ]

Form, symmetry and packing of biomacromolecules. V. Shells with boundaries at anti-nodes of resonant vibrations in icosahedral RNA viruses

A. Janner

Synopsis: Periodic shells in icosahedral RNA viruses are interpreted in terms of a resonator model.

Online 13 October 2011


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Acta Cryst. (2011). A67, 533-543  [ doi:10.1107/S0108767311036269 ]

Common arc method for diffraction pattern orientation

G. Bortel and M. Tegze

Synopsis: An orientation method based on the intersection arcs of continuous diffraction patterns is described and is shown to perform well on simulated patterns of single-particle diffraction experiments performed at X-ray free-electron laser sources.

Online 13 October 2011


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Acta Cryst. (2011). A67, 544-549  [ doi:10.1107/S0108767311037469 ]

A multi-dataset data-collection strategy produces better diffraction data

Z.-J. Liu, L. Chen, D. Wu, W. Ding, H. Zhang, W. Zhou, Z.-Q. Fu and B.-C. Wang

Synopsis: Theoretical analysis and experimental validation prove that a multi-dataset data-collection strategy produces better diffraction data. The readiness test is a simple and sensitive method for X-ray data-collection system evaluation and a benchmark.

Online 18 October 2011


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Acta Cryst. (2011). A67, 550-556  [ doi:10.1107/S0108767311037238 ]

Polarization-dependent X-ray six-beam pinhole topographs for a channel-cut silicon crystal

K. Okitsu, Y. Yoda, Y. Imai and Y. Ueji

Synopsis: Experimentally obtained and computer-simulated X-ray six-beam pinhole topographs based on the n-beam Takagi-Taupin (T-T) equation are reported for a channel-cut silicon crystal. It has been clarified that the algorithm to integrate the n-beam T-T equation can calculate the X-ray wavefield in a crystal of complex shape.

Online 18 October 2011


short communications


 

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Acta Cryst. (2011). A67, 557-558  [ doi:10.1107/S010876731103724X ]

On the polarization state of X-rays generated using a rotating four-quadrant X-ray phase retarder system

K. Okitsu

Synopsis: A method of calculating the polarization state of X-rays transmitted through a rotating four-quadrant X-ray phase retarder system is described using Jones calculus.

Online 18 October 2011


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Acta Cryst. (2011). A67, 559-560  [ doi:10.1107/S0108767311037251 ]

Computer-simulated X-ray three-beam pinhole topographs for spherical silicon crystals

K. Okitsu

Synopsis: Computer-simulated pinhole topographs for spherical silicon crystals are reported and compared with those for parallel-plate crystals.

Online 18 October 2011


book reviews


 

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Acta Cryst. (2011). A67, 561-563  [ doi:10.1107/S0108767311039523 ]

Fundamentals of Crystallography

Online 18 October 2011


international union of crystallography


 

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Acta Cryst. (2011). A67, 564-565  [ doi:10.1107/S010876731104298X ]

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Online 18 October 2011


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