Kyushu University Academic Staff Educational and Research Activities Database
List of Papers
Oishi-Tomiyasu Ryoko Last modified date:2023.11.22

Professor / Division for Intelligent Societal Implementation of Mathmatical Computation / Institute of Mathematics for Industry


Papers
1. Ryoko Oishi-Tomiyasu, On some algebraic properties of CM-types of CM-fields and their reflexes, Journal of Number Theory, 10.1016/j.jnt.2010.03.021, 130, 11, 2442-2466, 2010.11, The purpose of this paper is to show that the reflex fields of a given CM-field K are equipped with a certain combinatorial structure that has not been exploited yet.The first theorem is on the abelian extension generated by the moduli and the b-torsion points of abelian varieties of CM-type, for any natural number b. It is a generalization of the result by Wei on the abelian extension obtained by the moduli and all the torsion points. The second theorem gives a character identity of the Artin L-function of a CM-field K and the reflex fields of K. The character identity pointed out by Shimura (1977) in [10] follows from this.The third theorem states that some Pfister form is isomorphic to the orthogonal sum of TrK*(Φ)/Q(a{topbar}a) defined on the reflex fields ⊕Φ∈ΛK*(Φ). This result suggests that the theory of complex multiplication on abelian varieties has a relationship with the multiplicative forms in higher dimension. For a video summary of this paper, please click here or visit http://www.youtube.com/watch?v=IIwksVYV5YE. © 2010 Elsevier Inc..
2. R. Oishi-Tomiyasu, Rapid Bravais-lattice determination algorithm for lattice parameters containing large observation errors, Acta Crystallographica Section A: Foundations of Crystallography, 10.1107/S0108767312024579, 68, 5, 525-535, 2012.09, A new Bravais-lattice determination algorithm is introduced herein. For error-stable Bravais-lattice determination, Andrews & Bernstein [Acta Cryst. (1988), A44, 1009-1018] proposed the use of operations to search for nearly Buerger-reduced cells. Although these operations play an essential role in their method, they increase the computation time, in particular when lattice parameters obtained in (powder) auto-indexing are supposed to contain large errors. The new algorithm requires only several permutation matrices in addition to the operations that are necessary when the lattice parameters have exact values. As a result, the computational efficiency of error-stable Bravais-lattice determination is improved considerably. Furthermore, the new method is proved to be error stable under a very general assumption. The detailed algorithms and the set of matrices sufficient for error-stable determination are presented. © 2012 International Union of Crystallography Printed in Singapore-all rights reserved..
3. R. Oishi-Tomiyasu, M. Yonemura, T. Morishima, Application of matrix decomposition algorithms for singular matrices to the Pawley method in Z-Rietveld, Journal of Applied Crystallography, 10.1107/S0021889812003998, 45, 2, 299-308, 2012.02, Z-Rietveld is a program suite for Rietveld analysis and the Pawley method; it was developed for analyses of powder diffraction data in the Materials and Life Science Facility of the Japan Proton Accelerator Research Complex. Improvements have been made to the nonlinear least-squares algorithms of Z-Rietveld so that it can deal with singular matrices and intensity non-negativity constraints. Owing to these improvements, Z-Rietveld successfully executes the Pawley method without requiring any constraints on the integrated intensities, even in the case of severely or exactly overlapping peaks. In this paper, details of these improvements are presented and their advantages discussed. A new approach to estimate the number of independent reflections contained in a powder pattern is introduced, and the concept of good reflections proposed by Sivia [J. Appl. Cryst. (2000), 33, 1295-1301] is shown to be explained by the presence of intensity non-negativity constraints, not the intensity linear constraints. © 2012 International Union of Crystallography Printed in Singapore-all rights reserved..
4. R. Oishi-Tomiyasu, Reversed de Wolff figure of merit and its application to powder indexing solutions, Journal of Applied Crystallography, 10.1107/S0021889813018773, 46, 5, 1277-1282, 2013.10, Two new figures of merit for powder indexing solutions are proposed: the reversed figure of merit M n Rev and the symmetric figure of merit M n Sym. These are naturally suggested by the theory underlying the de Wolff figure of merit M n. Nevertheless, M n Rev has characteristics opposite to those of M n with regard to sensitivity to impurity peaks and extinct reflections. M n Sym has intermediate properties between M n and M n Rev. Applications of the new figures of merit to powder indexing solutions and zero-point shift estimation are introduced. All of the figures of merit are available from the powder auto-indexing software Conograph (http://sourceforge.jp/projects/conograph/; http://research.kek.jp/people/rtomi/ ConographGUI/web-page.html). © 2013 International Union of Crystallography Printed in Singapore - all rights reserved..
5. R. Oishi-Tomiyasu, Distribution rules of systematic absences on the Conway topograph and their application to powder auto-indexing, Acta Crystallographica Section A: Foundations of Crystallography, 10.1107/S0108767313021740, 69, 6, 603-610, 2013.11, This paper presents several general properties of systematic absences that are available before unit-cell parameters and the space group have been determined. The properties are given in the form of distribution rules of Miller indices corresponding to systematic absences on a topograph. A topograph is a graph whose edges are associated with a set of four lattice vectors satisfying Ito's equation 2(|l 1 *|2 + |l 2 *|2) = |l 1 * + l 2 *|2 + |l 1 *-l 2 *|2. It is possible to integrate global information about extinct reflections by using topographs. As an example of the application of these rules, a new powder auto-indexing algorithm is introduced, focusing on its theoretical aspects. © 2013 International Union of Crystallography Printed in Singapore - all rights reserved..
6. R. Oishi-Tomiyasu, Robust powder auto-indexing using many peaks, Journal of Applied Crystallography, 10.1107/S1600576714000922, 47, 2, 593-598, 2014.04, A new powder auto-indexing method for the CONOGRAPH software [Oishi-Tomiyasu (2013). Acta Cryst. A69, 603-610] can carry out exhaustive powder auto-indexing in a short time, even if the q values of many peaks are used, with sufficient consideration given to their observational errors. This article explains that the use of many q values is essential to make powder auto-indexing robust against dominant zones and missing or false peaks in the input. Results from CONOGRAPH for 25 real diffraction patterns, including difficult cases, are presented. Owing to a sorting criterion for zones defined in the previous article, the computation times were reduced by a factor of between 18 and 250, and exhaustive powder auto-indexing was completed in 5 min at most. © 2014..
7. R. Oishi-Tomiyasu, Method to generate all the geometrical ambiguities of powder indexing solutions, Journal of Applied Crystallography, 10.1107/S1600576714023620, 47, 6, 2055-2059, 2014.12, © 2014 International Union of Crystallography. A new algorithm is reported that returns all the lattices with the same set of d spacings as that of a given lattice. The algorithm is useful for quickly checking lattice parameters obtained for a considered powder diffraction pattern and assessing the reliability of the results of powder indexing. The proposed algorithm was implemented as a new function in the powder indexing software Conograph (http://sourceforge.jp/projects/conograph/; http://research.kek.jp/people/rtomi/ConographGUI/web-page.html). Examples of real cases are reported to explain how the algorithm can be used..
8. Ryoko Oishi-Tomiyasu, Distribution rules of systematic absences on the Conway topograph and their application to powder auto-indexing (vol A69, pg 603, 2013), ACTA CRYSTALLOGRAPHICA A-FOUNDATION AND ADVANCES, 10.1107/S2053273315015065, 71, 628-628, 2015.11.
9. A. Esmaeili, T. Kamiyama, R. Oishi-Tomiyasu, New functions and graphical user interface attached to powder indexing software CONOGRAPH, JOURNAL OF APPLIED CRYSTALLOGRAPHY, 10.1107/S1600576717001145, 50, 651-659, 2017.04, The present status of powder indexing software CONOGRAPH as an integrated system with a graphical user interface is reported. The improvements to the peak search method and the other available functions are introduced. Computational results and times for CONOGRAPH are compared with those for ITO13, N-TREOR and DICVOL14 to clarify their differences..
10. K Tomiyasu, R Oishi-Tomiyasu, M Matsuda, K Matsuhira, A new mathematical approach to finding global solutions of the magnetic structure determination problem., Scientific reports, 10.1038/s41598-018-34443-2, 8, 1, 16228-16228, 2018.11, Determination of magnetic structure is an important analytical procedure utilized in various fields ranging from fundamental condensed-matter physics and chemistry to advanced manufacturing. It is typically performed using a neutron diffraction technique; however, finding global solutions of the magnetic structure optimization problem represents a significant challenge. Generally, it is not possible to mathematically prove that the obtained magnetic structure is a truly global solution and that no solution exists when no acceptable structure is found. In this study, the global optimization technique called semidefinite relaxation of quadratic optimization, which has attracted much interest in the field of applied mathematics, is proposed to use as a new analytical method for the determination of magnetic structure, followed by the application of polarized neutron diffraction data. This mathematical approach allows avoiding spurious local solutions, decreasing the amount of time required to find a tentative solution and finding multiple solutions when they exist..
11. Ryoko Oishi-Tomiyasu, Tomohito Tanaka, Junichi Nakagawa, Distribution rules of systematic absences and generalized de Wolff figures of merit applied to electron backscatter diffraction ab initio indexing, Journal of Applied Crystallography, 10.1107/S1600576721002120, 54, 624-635, 2021.04, A new method for electron backscatter diffraction ab initio indexing is reported that adopts several methods originally invented for powder indexing. Distribution rules of systematic absences and error-stable Bravais lattice determination are used to eliminate the negative influence of non-visible bands and erroneous information from visible bands. In addition, generalized versions of the de Wolff figures of merit are proposed as a new sorting criterion for the obtained unit-cell parameters, which can be used in both orientation determination and ab initio indexing from Kikuchi patterns. Computational results show that the new figures of merit work well, similar to the original de Wolff Mn. The ambiguity of the indexing solutions is also pointed out, which happens in particular for low-symmetry cells and may generate multiple distinct solutions even if very accurate positions of band centre lines and the projection centre are given. It is supposed that this is the reason why indexing was successful in an orthorhombic case but not in a triclinic cell..
12. Ramanujam Kamaraj, Ben Kane, Ryoko Oishi-Tomiyasu, Universal sums of generalized heptagonal numbers, JOURNAL OF NUMBER THEORY, 10.1016/j.jnt.2023.02.003, 249, 500-536, 2023.08, In this paper, we consider representations of integers as sums of heptagonal numbers with a prescribed number of repeats of each heptagonal number appearing in the sum. In particular, we investigate the classification of such sums which are universal, i.e., those that represent every positive integer. We prove an explicit finite bound such that a given sum is universal if and only if it represents positive integer up to the given bound. (c) 2023 Elsevier Inc. All rights reserved..
13. Oishi-Tomiyasu, R., Tanaka, T., Nakagawa, J., Distribution rules of systematic absences and generalized de Wolff figures of merit applied to electron backscatter diffraction ab initio indexing, Journal of Applied Crystallography, https://doi.org/10.1107/S1600576721002120, 54, 2, 624-635, 2021.04.
14. Ryoko Oishi-Tomiyasu, Positive-definite ternary quadratic forms with the same representations over ℤ, International Journal of Number Theory, 10.1142/S1793042120500785, 16, 7, 1493-1534, 2020.08, Kaplansky conjectured that if two positive-definite ternary quadratic forms have perfectly identical representations over ℤ, they are equivalent over ℤ or constant multiples of regular forms, or is included in either of two families parameterized by ℝ2. Our results aim to clarify the limitations imposed to such a pair by computational and theoretical approaches. First, the result of an exhaustive search for such pairs of integral quadratic forms is presented in order to provide a concrete version of the Kaplansky conjecture. The obtained list contains a small number of non-regular forms that were confirmed to have the identical representations up to 3,000,000 by computation. However, a strong limitation on the existence of such pairs is still observed, regardless of whether the coefficient field is ℚ or ℝ. Second, we prove that if two pairs of ternary quadratic forms have the identical simultaneous representations over ℚ, their constant multiples are equivalent over ℚ. This was motivated by the question why the other families were not detected in the search. In the proof, the parametrization of quartic rings and their resolvent rings by Bhargava is used to discuss pairs of ternary quadratic forms..
15. R. Oishi-Tomiyasu, Mathematical Tools that Connect Different Indexing Analyses, MDPI Proceedings (IOCC2020 proceedings), https://doi.org/10.3390/proceedings2020062008, 62, 1, 1-8, 2020.12.
16. K. Tomiyasu, Ryoko Tomiyasu, M. Matsuda, K. Matsuhira, A new mathematical approach to finding global solutions of the magnetic structure determination problem, Scientific reports, 10.1038/s41598-018-34443-2, 8, 1, 2018.12, Determination of magnetic structure is an important analytical procedure utilized in various fields ranging from fundamental condensed-matter physics and chemistry to advanced manufacturing. It is typically performed using a neutron diffraction technique; however, finding global solutions of the magnetic structure optimization problem represents a significant challenge. Generally, it is not possible to mathematically prove that the obtained magnetic structure is a truly global solution and that no solution exists when no acceptable structure is found. In this study, the global optimization technique called semidefinite relaxation of quadratic optimization, which has attracted much interest in the field of applied mathematics, is proposed to use as a new analytical method for the determination of magnetic structure, followed by the application of polarized neutron diffraction data. This mathematical approach allows avoiding spurious local solutions, decreasing the amount of time required to find a tentative solution and finding multiple solutions when they exist..
17. Yoshihisa Ishikawa, Junrong Zhang, Ryoji Kiyanagi, Masao Yonemura, Takeshi Matsukawa, Akinori Hoshikawa, Toru Ishigaki, Shuki Torii, Ryoko Tomiyasu, Takashi Kamiyama, Z-MEM, Maximum Entropy Method software for electron/nuclear density distribution in Z-Code, Physica B: Condensed Matter, 10.1016/j.physb.2018.03.034, 551, 472-475, 2018.12, Maximum Entropy Method (MEM) is one of powerful tools for material science. We developed the program Z-MEM for evaluation of electron and nuclear density distribution by MEM analysis and Fourier synthesis. This code is designed by the multi-threading library OpenMP, so that the calculation performance is significantly improvements for MEM analysis. Z-MEM is bundled in Z-Rietveld, which is Rietveld software for X-ray and neutron powder diffraction, via the application programming interface (API). Since Z-MEM have equipped with the graphical user interface operations, users can perform from Rietveld refinement to MEM analysis seamlessly..
18. Ryoko Tomiyasu, Application of convex optimization to identification of atomic species from diffraction patterns, Powder Diffraction, 10.1017/S0885715616000804, 32, S1, S179-S185, 2017.09, Computational methods and a program to obtain crystal structures that have the perfectly identical diffraction patterns, i.e. structure factors with the same absolute values and the same lattice symmetry are discussed. This is directly related to the uniqueness of solutions in crystal structure determination of single-crystal/powder-crystal samples from diffraction data. In order to solve the problem, it is necessary to solve a system of quadratic equations. The framework of positive-semidefinite programming is used herein to solve the system efficiently..
19. A. Esmaeili, T. Kamiyamaa, Ryoko Tomiyasu, New functions and graphical user interface attached to powder indexing software, Journal of Applied Crystallography, 10.1107/S1600576717001145, 50, 651-659, 2017.01, The present status of powder indexing software CONOGRAPH as an integrated system with a graphical user interface is reported. The improvements to the peak search method and the other available functions are introduced. Computational results and times for CONOGRAPH are compared with those for ITO13, N-TREOR and DICVOL14 to clarify their differences..
20. Ryoko Tomiyasu, A table of geometrical ambiguities in powder indexing obtained by exhaustive search, Acta Crystallographica Section A: Foundations and Advances, 10.1107/S2053273315021725, 72, 73-80, 2016.01, Geometrical ambiguity means the cases in which more than one powder indexing solution exists. Using a new function implemented in the powder indexing software CONOGRAPH, unit cells that involve geometrical ambiguity are exhaustively searched. As a result, many unknown cases are obtained, although the number of such unit cells is still rather limited. It is also proven that the number of solutions in powder auto-indexing is not always unique, but generally finite..
21. Ryoko Tomiyasu, Erratum
Distribution rules of systematic absences on the Conway topograph and their application to powder auto-indexing (Acta Crystallographica Section A: Foundations and Advances (2013) A69 (603-610)), Acta Crystallographica Section A: Foundations and Advances, 10.1107/S2053273315015065, 71, 2015.01.
22. Ryoko Tomiyasu, Method to generate all the geometrical ambiguities of powder indexing solutions, Journal of Applied Crystallography, 10.1107/S1600576714023620, 47, 6, 2055-2059, 2014.12, A new algorithm is reported that returns all the lattices with the same set of d spacings as that of a given lattice. The algorithm is useful for quickly checking lattice parameters obtained for a considered powder diffraction pattern and assessing the reliability of the results of powder indexing. The proposed algorithm was implemented as a new function in the powder indexing software Conograph (http://sourceforge.jp/projects/conograph/; http://research.kek.jp/people/rtomi/ConographGUI/web-page.html). Examples of real cases are reported to explain how the algorithm can be used..
23. S. Torii, M. Yonemura, Y. Ishikawa, P. Miao, Ryoko Tomiyasu, S. Satoh, Y. Noda, T. Kamiyama, Improvement of instrument devices for super high resolution powder diffractometer at J-PARC, 1st Conference on Light and Particle Beams in Materials Science 2013, LPBMS 2013 Journal of Physics: Conference Series, 10.1088/1742-6596/502/1/012052, 502, 1, 2014.01, Super High Resolution Powder Diffractometer SuperHRPD [1] at J-PARC have suffered damage by the Great East Japan Earthquake on 11 March 2011. After temporarily restoration work, the general user program has been started since April 2012. Full-fledged restoration of the temporarily restored devices is being carried out in 2013. The absorber materials for two disk choppers were replaced to 10B4C which improved quality of incident spectrum. The new detector system of 8 mm diameter position sensitive detectors was developed, and the test experiments showed excellent results..
24. Ryoko Tomiyasu, Robust powder auto-indexing using many peaks, Journal of Applied Crystallography, 10.1107/S1600576714000922, 47, 2, 593-598, 2014.01, A new powder auto-indexing method for the CONOGRAPH software [Oishi-Tomiyasu (2013). Acta Cryst. A69, 603-610] can carry out exhaustive powder auto-indexing in a short time, even if the q values of many peaks are used, with sufficient consideration given to their observational errors. This article explains that the use of many q values is essential to make powder auto-indexing robust against dominant zones and missing or false peaks in the input. Results from CONOGRAPH for 25 real diffraction patterns, including difficult cases, are presented. Owing to a sorting criterion for zones defined in the previous article, the computation times were reduced by a factor of between 18 and 250, and exhaustive powder auto-indexing was completed in 5 min at most..
25. Ryoko Tomiyasu, Distribution rules of systematic absences on the Conway topograph and their application to powder auto-indexing, Acta Crystallographica Section A: Foundations of Crystallography, 10.1107/S0108767313021740, 69, 6, 603-610, 2013.11, This paper presents several general properties of systematic absences that are available before unit-cell parameters and the space group have been determined. The properties are given in the form of distribution rules of Miller indices corresponding to systematic absences on a topograph. A topograph is a graph whose edges are associated with a set of four lattice vectors satisfying Ito's equation 2(|l 1 *|2 + |l 2 *|2) = |l 1 * + l 2 *|2 + |l 1 *-l 2 *|2. It is possible to integrate global information about extinct reflections by using topographs. As an example of the application of these rules, a new powder auto-indexing algorithm is introduced, focusing on its theoretical aspects..
26. Ryoko Tomiyasu, Reversed de Wolff figure of merit and its application to powder indexing solutions, Journal of Applied Crystallography, 10.1107/S0021889813018773, 46, 5, 1277-1282, 2013.10, Two new figures of merit for powder indexing solutions are proposed: the reversed figure of merit M n Rev and the symmetric figure of merit M n Sym. These are naturally suggested by the theory underlying the de Wolff figure of merit M n. Nevertheless, M n Rev has characteristics opposite to those of M n with regard to sensitivity to impurity peaks and extinct reflections. M n Sym has intermediate properties between M n and M n Rev. Applications of the new figures of merit to powder indexing solutions and zero-point shift estimation are introduced. All of the figures of merit are available from the powder auto-indexing software Conograph (http://sourceforge.jp/projects/conograph/; http://research.kek.jp/people/rtomi/ ConographGUI/web-page.html)..
27. Ryoko Tomiyasu, Rapid Bravais-lattice determination algorithm for lattice parameters containing large observation errors, Acta Crystallographica Section A: Foundations of Crystallography, 10.1107/S0108767312024579, 68, 5, 525-535, 2012.09, A new Bravais-lattice determination algorithm is introduced herein. For error-stable Bravais-lattice determination, Andrews & Bernstein [Acta Cryst. (1988), A44, 1009-1018] proposed the use of operations to search for nearly Buerger-reduced cells. Although these operations play an essential role in their method, they increase the computation time, in particular when lattice parameters obtained in (powder) auto-indexing are supposed to contain large errors. The new algorithm requires only several permutation matrices in addition to the operations that are necessary when the lattice parameters have exact values. As a result, the computational efficiency of error-stable Bravais-lattice determination is improved considerably. Furthermore, the new method is proved to be error stable under a very general assumption. The detailed algorithms and the set of matrices sufficient for error-stable determination are presented..
28. Ryoko Tomiyasu, M. Yonemura, T. Morishima, Application of matrix decomposition algorithms for singular matrices to the Pawley method in Z-Rietveld, Journal of Applied Crystallography, 10.1107/S0021889812003998, 45, 2, 299-308, 2012.02, Z-Rietveld is a program suite for Rietveld analysis and the Pawley method; it was developed for analyses of powder diffraction data in the Materials and Life Science Facility of the Japan Proton Accelerator Research Complex. Improvements have been made to the nonlinear least-squares algorithms of Z-Rietveld so that it can deal with singular matrices and intensity non-negativity constraints. Owing to these improvements, Z-Rietveld successfully executes the Pawley method without requiring any constraints on the integrated intensities, even in the case of severely or exactly overlapping peaks. In this paper, details of these improvements are presented and their advantages discussed. A new approach to estimate the number of independent reflections contained in a powder pattern is introduced, and the concept of good reflections proposed by Sivia [J. Appl. Cryst. (2000), 33, 1295-1301] is shown to be explained by the presence of intensity non-negativity constraints, not the intensity linear constraints..
29. Shuki Torii, Masao Yonemura, Teguh Yulius Surya Panca Putra, Junrong Zhang, Ping Miao, Takashi Muroya, Ryoko Tomiyasu, Takahiro Morishima, Setsuo Sato, Hidenori Sagehashi, Yukio Noda, Takashi Kamiyama, Super high resolution powder diffractometer at J-PARC, journal of the physical society of japan, 10.1143/JPSJS.80SB.SB020, 80, SUPPL. B, 2011.12, Super High Resolution Powder Diffractometer, SuperHRPD, is located at about 100 m from a thin side of a decoupled poisoned moderator at the Materials and Life Science Experimental Facility in the Japan Proton Accelerator Research Complex. The first neutron was produced successfully from a spallation neutron source in J-PARC in the end of May of 2008, and SuperHRPD has achieved the world best resolution Δd/d = 0.035% in June using the existing Sirius
1
) chamber. In the summer of 2009, a new SuperHRPD chamber was installed aiming at increasing the detector solid angle and expanding d-range / Q-range, with at most 1500 one-dimensional
3
He position-sensitive detectors of 1/2 inch in diameter. The on-beam commissioning of the new SuperHRPD was started in the autumn of 2009..
30. Ryoko Tomiyasu, On some algebraic properties of CM-types of CM-fields and their reflexes, Journal of Number Theory, 10.1016/j.jnt.2010.03.021, 130, 11, 2442-2466, 2010.11, The purpose of this paper is to show that the reflex fields of a given CM-field K are equipped with a certain combinatorial structure that has not been exploited yet.The first theorem is on the abelian extension generated by the moduli and the b-torsion points of abelian varieties of CM-type, for any natural number b. It is a generalization of the result by Wei on the abelian extension obtained by the moduli and all the torsion points. The second theorem gives a character identity of the Artin L-function of a CM-field K and the reflex fields of K. The character identity pointed out by Shimura (1977) in [10] follows from this.The third theorem states that some Pfister form is isomorphic to the orthogonal sum of TrK*(Φ)/Q(a{topbar}a) defined on the reflex fields ⊕Φ∈ΛK*(Φ). This result suggests that the theory of complex multiplication on abelian varieties has a relationship with the multiplicative forms in higher dimension. For a video summary of this paper, please click here or visit http://www.youtube.com/watch?v=IIwksVYV5YE..
31. Ryoko Tomiyasu, M. Yonemura, A. Hoshikawa, T. Ishigaki, K. Mori, S. Torii, T. Morishima, T. Kamiyama, New approach to the indexing of powder diffraction patterns using topographs, Zeitschrift fur Kristallographie, Supplement, 10.1524/zksu.2009.0002, 30, 15-20, 2009.12, A new indexing algorithm is proposed that searches solutions thoroughly and quickly. The algorithm is well established for poor quality data e.g. for data containing some false peaks, or for those cases that peak positions coincide with two or more different lattices. It has succeeded for any lattice symmetry by carrying out the thorough search in several minutes at most. A graph structure called topograph, first introduced by the mathematician Conway, plays an important role in our method. In this paper, we introduce the algorithm and give some preliminary results..
32. T. Ishigaki, A. Hoshikawa, M. Yonemura, T. Morishima, T. Kamiyama, Ryoko Tomiyasu, K. Aizawa, T. Sakuma, Y. Tomota, M. Arai, M. Hayashi, K. Ebata, Y. Takano, K. Komatsuzaki, H. Asano, Y. Takano, T. Kasao, IBARAKI materials design diffractometer (iMATERIA)-Versatile neutron diffractometer at J-PARC, Nuclear Instruments and Methods in Physics Research, Section A: Accelerators, Spectrometers, Detectors and Associated Equipment, 10.1016/j.nima.2008.11.137, 600, 1, 189-191, 2009.02, Ibaraki prefecture, the local government of the area for J-PARC site, was decided to build a versatile neutron diffractometer (IBARAKI Materials Design Diffractometer, iMATERIA) to promote an industrial application for neutron beam in J-PARC. iMATERIA is planned to be a high throughput diffractometer so that materials engineers and scientists can use it like the chemical analytical instruments in their materials development process. It covers in d range 0.18
33. Ryoko Tomiyasu, M. Yonemura, Y. Nishimaki, S. Torii, A. Hoshikawa, T. Ishigaki, T. Morishima, K. Mori, T. Kamiyama, Rietveld analysis software for J-PARC, Nuclear Instruments and Methods in Physics Research, Section A: Accelerators, Spectrometers, Detectors and Associated Equipment, 10.1016/j.nima.2008.11.056, 600, 1, 94-96, 2009.02, A new analysis software suite, Z-Code, is under development for powder diffraction data analyses in the Materials and Life Science Facility (MLF) of the Japan Proton Accelerator Research Complex (J-PARC). This software suite comprises data processing, data analyses, graphical user interface and visualization software. As a part of Z-Code, a Rietveld analysis program for neutron (TOF and angle dispersive) and X-ray data, Z-Rietveld, has been developed. Here we report the basic traits and some significant features of Z-Rietveld..