OASIS
(project started in 1988)
Current version:
OASIS 4.2 - a program of direct-method phasing based on a partial model with or
without SAD/SIR information.
- Operating systems: Linux and MAC OS X
- Features:
- Direct-method breaking the SAD/SIR phase ambiguity
- Incorporating lack-of-closure error in direct-method phasing
- Incorporating partial-structure information in phase derivation
- Dual-space SAD/SIR phasing and fragment extension by the combination of
OASIS with density-modification and model-building programs
- Dual-space partial model completion by the
combination of OASIS with density-modification and model-building
programs in the absence of SAD/SIR information
- Dual-space phase/fragmant extension
- Applications
- Download from Github or Gitee
VEC
(project started in 1994)
A program package for visual computing in electron
crystallography. The program is written in C++ and Fortran.
- Operating systems: Windows95, 98, NT, 2000 and XP
- Functions & Features:
- Preliminary processing of electron microscopy images
- Indexing and diffraction-intensity extracting of electron diffraction patterns
- Direct-method deconvolution of a single electron microscopy image
- Resolution enhancement of electron microscopy images using direct methods
- Simulation of dynamical/kinematical electron diffraction patterns and electron microscopy
images for conventional and modulated crystals
- 2-, 3- and 4-dimensional FFT
- 2-dimensional half-tone-graph display of 2-, 3- and 4-dimensional Fourier maps
- Contour mapping of 2-dimensional patterns
- Ab-initio direct-method solution of incommensurate one-dimensionally modulated structures
and composite structures of two subsystems
- Tutorials
- Applications
- Download from Github or Gitee
DIMS (project started in 1991)
A direct-method program written in Fortran
for solving one-dimensionally modulated structures and composite structures consists of two
sub-systems.
- Operating systems: Unix, Windows95, 98, NT, 2000 and XP
- Features:
- There are two versions of DIMS: the stand-alone version and the VEC version. The latter
forms a part of the program VEC and can only be run under MS Windows.
- The program can derive symmetry generators according to the input two-line symbols of
(3+1)-dimensional superspace groups. Alternatively, it allows also manual input of
symmetry generators. For one-line symbols, the program symbol1to2 can convert
them to the corrsponding two-line symbols (see Tutorials). In VEC,
this will be done automatically.
- For ordinary incommensurate modulated structures, phases of main reflections are assumed
to be known in advance via convensional methods for 3-dimensional periodic structures.
DIMS is used to derive phases of satellite reflections based on the known phases of main
reflections. In this case, DIMS can be used with X-ray-, electron- and neutron-diffraction
data.
- For composite structures, phases of main reflections should be derived first by DIMS.
Then they are input to DIMS as known phases to derive phases of satellites. In this case,
DIMS can be used with only X-ray diffraction data.
For the VEC version only:
- I/O data of DIMS can be displayed and manipulated by the
sophisticated graphic interface of VEC.
- 4D-Fourier maps phased by DIMS can be calculated, displayed and
interpreted within VEC.
- The program MIMS can help with building a 4D-structure model
from the 4D-Fourier map.
- Tutorials
- Applications
- Download from Github or Gitee
SAPI (project started in 1985)
The name SAPI is an abbreviation of
"Structure Analysis Programs with Intelligent control". It may also be read inversely
as "Institute of Physics, Academia Sinica". SAPI is written in Fortran for crystallographic
calculations and C++ for graphic operations. SAPI is based on MULTAN and differs from it
mainly by the ability of resolving phase ambiguities due to pseudo symmetry.
- Operating systems: Windows95, 98, NT, 2000 and XP
- Features:
- The program can automatically detect and handle diffraction data having
pseudo-translational symmetry and lead directly to the superstructure without relying
on an assumed structure model.
- The program can recognize pseudo-centrosymmetric solutions when dealing with
non-centrosymmetric structures. In addition, the program can break the enantiomorphous
ambiguity given the "atomic positions" of both enantiomorphs.
- The program can tune automatically some controlling parameters
according to the feature of the input data.
- The program enables combination of Patterson and direct methods. Besides, subroutines
are provided for automatic Patterson analysis of heavy-atom containing structures.
- Sophisticated graphic interface is provided for data preparation, program control and
for displaying and manipulating output results.
- Tutorials (WinHelp
)
- History
- Download from Github or Gitee