Yuki Chiba

Fabrication of proton conducting thin films of SrZrO3 and SrCeO3 and their fundamental characterization

Abstract Proton conducting thin films of SrZrO 3 and SrCeO 3 were fabricated by the pulsed laser ablation method using ArF excimer laser. The thin films of SrCeO 3 and SrZrO 3 were grown in the [100] direction on the SrTiO 3 (100) substrate and in the [211] direction on the MgO(100) substrate and on the Al 2 O 3 substrate. The Raman scattering spectra show that the thin films grown in the low P O 2 contain lots of oxygen ion vacancies compared to bulk crystals.

Raman scattering of single-crystal SrZrO3

Single-crystal SrZrO3 with perovskite-type structure was grown by a floating-zone method. The polarized Raman scattering spectra were measured at room temperature. The observed Raman spectra were interpreted on the basis of a factor group analysis for the group D2h. Although 24 Raman active modes were expected, 15 bands were observed and the mode assignments were made by using D2h symmetry. Vibrational mode frequencies calculated using a rigid-ion model were helpful for the assignment of B1g and B3g modes and the interatomic potentials were estimated.

Program transformation by templates based on term rewriting

Huet and Lang (1978) presented a framework of automated program transformation based on lambda calculus in which programs are transformed according to a given program transformation template. They introduced a second-order matching algorithm of simply-typed lambda calculus to verify whether the input program matches the template. They also showed how to validate the correctness of the program transformation using the denotational semantics.We propose in this paper a framework of program transformation by templates based on term rewriting. In our new framework, programs are given by term rewriting systems. To automate our program transformation, we introduce a term pattern matching problem and present a sound and complete algorithm that solves this problem.We also discuss how to validate the correctness of program transformation in our framework. We introduce a notion of developed templates and a simple method to construct such templates without explicit use of induction. We then show that in any program transformation by developed templates the correctness of the transformation can be verified automatically. In our framework the correctness of the program transformation is discussed based on the operational semantics. This is a sharp contrast to Huet and Langs framework.

Constructor-Based Inductive Theorem Prover

Constructor-based Theorem Prover (CITP) is a tool for proving inductive properties of software systems specified with constructor-based logics. CITP is equipped with a default proof strategy for the automated verification of Observational Transitional Systems (OTS), but the area of applications is not restricted to OTS. The proof strategy can be customised by the user, or the basic tactics can be applied step-by-step. The tool features are exhibited on concrete examples, showing how to perform verification with CITP.

Local structures in Y3+-doped SrCeO3 crystals studied by site-selective spectroscopy

Abstract We have measured site-selective luminescence spectra of Eu 3+ in the perovskite proton conductors Y 3+ -doped SrCeO 3 single crystals. A strong red shift of the 5 D 0 - 7 F 0 transition of Eu 3+ is observed with H 2 O-treatment. The site-selective spectra of these reveals that (i) four different sites of Eu 3+ ions exist in protonated SrCeO 3 system at low Y 3+ concentration and (ii) that the relative intensity among these sites strongly depends on the dopant concentration.

SMT-Based Bounded Model Checking for OSEK/VDX Applications

With the growing demands for automotive auxiliary functions, more and more complex applications have been developed based on OSEK/VDX OS. However, how to check the developed applications is becoming a challenge for developers. Although some invaluable formal methods have been proposed to check actual software, these methods cannot be directly employed to check OSEK/VDX applications. In this paper, we describe and develop an approach to check OSEK/VDX applications using SMT-based bounded model checking. We also implement a prototype tool and conduct many experiments on several examples. The experiment results show that our approach can completely check the properties associated with (i) variables, (ii) mutual exclusion, (iii) service API, and (iv) tasks execution sequences of developed applications.

A Spin-Based Approach for Checking OSEK/VDX Applications

OSEK/VDX, a standard of automobile OS, has been widely adopted by many manufacturers to design and develop a vehicle-mounted OS. With the increasing functionalities in vehicles, more and more applications are developed based on the OSEK/VDX OS. However, how to ensure the reliability of the developed OSEK/VDX applications is becoming a challenge for developers. As to ensure the reliability of the developed OSEK/VDX applications, model checking as an exhaustive checking technique can be applied to verify the developed OSEK/VDX applications. In our previous work, we have proposed a bounded model checking approach to verify the OSEK/VDX applications. In this paper, we describe and develop an alternative approach to verify the OSEK/VDX applications based on the Spin. There are two motivations in this paper, one is to show how to use Spin to verify the OSEK/VDX applications, and the other is to investigate the effectiveness of our bounded model checking approach and Spin-based approach based on the experiments.

Local structure around Yb in SrZr1-xYbxO3

Local structures around Yb ions in the proton conductor Yb-doped SrZrO3 have been investigated at room temperature by the EXAFS (extended x-ray absorption fine structure) technique. The radial structure functions from the Zr K edge in SrZrO3, SrZr0.95Yb0.05O3 and SrZr0.9Yb0.1O3 and the Yb LIII edge in Yb2O3 show clear contributions by next-nearest ions at 3.0-4.0 A, while those from the Yb LIII edge in SrZr0.95Yb0.05O3 and SrZr0.9Yb0.1O3 are mainly constructed by a first-nearest signal. Moreover, the nearest Yb-O distributions at 1.0-2.0 A have a side peak with a strong intensity in both SrZr0.95Yb0.05O3 and SrZr0.9Yb0.1O3. It is shown from the analyses of the side peak that the nearest Yb-O bonds consist of two distances (1.96 and 2.18 A). Two structural models around the Yb ion have been suggested and discussed from these results.

Far-Infrared Reflectivity Spectra of the Hydrogen-Bonded Ferroelectric KH2PO4 Measured by Synchrotron Radiation

Far infrared reflectivity spectra of hydrogen-bonded ferroelectric KH 2 PO 4 are measured by using synchrotron radiation in the photon-energy region from 5 to 250 cm -1 . The strong relaxational mode is found in the infrared spectra. This result is consistent with the results which have been obtained by the hyper-Raman and Raman scattering, but inconsistent with the results which have been observed by the ordinary infrared light source.

Yes! You Can Use Your Model Checker to Verify OSEK/VDX Applications

OSEK/VDX, a standard of automobile OS, has been widely adopted by many manufacturers to design and develop a vehicle-mounted OS. With the increasing functionalities in vehicles, more and more complex applications are developed based on the OSEK/VDX OS. However, how to ensure the reliability of developed applications is becoming a challenge for developers. As to ensure the reliability of developed applications, model checking as an exhaustive technique can be applied to verify the OSEK/VDX applications. There exist many model checkers that have been successfully applied to verify sequential software and general multi-threaded software. However, it is hard to directly use existing model checkers to precisely verify OSEK/VDX applications, since the execution characteristics of OSEK/VDX applications are different from the sequential software and general multi-threaded software. In this paper, we describe and develop an approach to translate OSEK/VDX applications into sequential programs in order to employ existing model checkers to precisely verify OSEK/VDX applications. The value of our approach is that it can be considered as a front-end translator for enabling existing model checkers to verify OSEK/VDX applications.