43 research outputs found
Lipase‐Palladium Co‐catalyzed Dynamic Kinetic Resolution of Racemic Allylic Esters
No full textThis is the accepted version of the following article: Oono Masato, Yamada Akane, Kimura Masanari, et al. Lipase‐Palladium Co‐catalyzed Dynamic Kinetic Resolution of Racemic Allylic Esters. Chemistry – A European Journal, e202404406, which has been published in final form at https://doi.org/10.1002/chem.202404406. This article may be used for non-commercialpurposes in accordance with the Wiley Self-ArchivingPolicy [https://authorservices.wiley.com/author-resources/Journal-Authors/licensing/self-archiving.html]Dynamic kinetic resolution (DKR) by combining lipase-catalyzed esterification of racemic sec-alcohols and in situ racemization has been widely studied; however, reports on DKR involving lipase-catalyzed hydrolysis of racemic esters are scarce. This problem is probably due to the lack of more effective and general racemization methods. Herein, we report the enhanced hydrolytic DKR of racemic allylic esters. The discovery of the monodentate ligand P[C6H3-2,6-(OMe)2]3, which in situ generates Pd complex(es) highly reactive to racemization and the NaOAc-mediated acceleration of racemization, are notable breakthroughs. Consequently, the DKR of racemic allylic esters can be completed in a few hours at 40 °C in most cases, yielding optically active allylic alcohols (93% to >99% ee) in 58%–91% isolated yields with minimal side reactions
Some problems on spatial patterns in nonequilibrium systems
No full textIn this thesis, we study the evolution of spatial patterns in two nonequilibrium systems."In Chapter 1, we study the steady state of a 1-d cellular automata (CA) model of chemical turbulence. Empirically there are two interesting types of space-time patterns (depending on model parameters): a S phase which seems to contain solitons and a T phase which seems to be turbulent. We show that the macroscopic phases can be predicted from the microscopic dynamics. We define the thermodynamic limit of the steady state of CAs and show that the steady state of the S phase is trivial and the T phase exhibits a Gibbs state. We explicitly calculate the T phase steady state and find an approximate form for the energy functional which generates the Gibbs state. We show that there is no adequate characterization of turbulent behavior in CAs and introduce a quantity the ""P-entropy"" which is positive if the CA patterns are turbulent and zero otherwise. We show the P-entropy for the T phase is positive."In Chapter 2, we consider the consequences of the dynamical scaling hypothesis in phase ordering dynamics. We assume that the dynamics are governed by the Cahn-Hilliard-Cook (CHC) and time-dependent Ginzburg-Landau equations and show that the scaling hypothesis restricts the asymptotic growth rate of the length-scale of the patterns and the small wavevector behavior of the form factor. Specifically, if the form factor S\sb{k}() grows as k\sp{\delta} for small , then 4 (for the CHC dynamics). We find that experimental data indicates = 4. We also show that the CHC equation is sometimes inadequate for describing phase ordering dynamics. An alternative to the CHC model by Oono, Kitahara and Jasnow is examined. We find that many features of phase ordering dynamics are robust with respect to changing the dynamics.Made available in DSpace on 2011-05-07T14:08:14Z (GMT). No. of bitstreams: 2
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Cell dynamical system approach to block copolymers
No full textIn this thesis we discuss a mesoscale model of block-copolymer (BCP) microphase separation dynamics based on a cell dynamics system (CDS) model. The model suggests a partial differential equation (PDE) model that allows us to find a close relation between the block copolymer and spinodal decomposition problems. A detailed numerical study of the CDS model is given, which indicates that hydrodynamic effects are crucial for very late time ordering processes. The strong segregation regime is studied analytically with the aid of exactly solvable PDE model, which is suggested by the universality supported by the CDS simulations. The results obtained show that dimensional analysis gives the correct exponent for the block copolymer lamellar thickness.Made available in DSpace on 2011-05-07T13:14:45Z (GMT). No. of bitstreams: 2
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Some problems on nonequilibrium systems
No full textIn this thesis, we study the evolution of two nonequilibrium systems: one is of practical significance for present technologies, and the other is of conceptual importance for future theoretical research.In chapter one, we model the -\delta\sp\prime two-phase region in the Al-Li binary alloy system utilizing a coarse-grained phenomenological free energy. Mesoscopic phenomenology provides a natural setting for studying the system at high temperatures and allows for efficient and realistic computer simulations. From general empirical observations, we construct a bulk free energy and identify universal features of the free energy form. We find that our model is able to sufficiently account for both the effects of structural ordering and spinodal decomposition.In chapter two, we investigate the classical XY magnetic spin system subject to time-dependent magnetic fields as an example of a simple but non-trivial system that is far from equilibrium. Infinite-range coupling between the spin systems is assumed. We limit our investigation to elliptical magnetic fields, giving special attention to the limiting cases of AC and rotating fields.Additionally, we investigate the discotic-biaxial phase transition of the homeotropically aligned nematic liquid crystals, since this system has many features in common with the XY magnetic system, and appears to be experimentally accessible.Made available in DSpace on 2011-05-07T12:17:11Z (GMT). No. of bitstreams: 2
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Some Observations on the Organization of History Curriculua : A Case Study of History Learning among Six Graders at the Wako Elementary School in Tsurukawa, Tokyo
No full textapplication/pdfThis paper focuses on History Education. There are three types how to construct educational contents, namely a chronological approach to history, an approach to concentrate on modern and contemporary history and an approach to focus certain topics or events. The author reviewed recent trends of History Education. As a case study, the author took up practice by Mr.Yuichi Oono, targeted at sixth grade children in Wako Tsurukawa elementary school, and the author characterized Mr. Oono’s practice as a type of concentrating to modern and contemporary history. The author investigated his educational method from the viewpoints of cognitive development of children and educational values. The author paid attention to his sense of the time, such as "an era of parents", "an era of grand parents" and also his narrative materials which were found and arranged by himself.departmental bulletin pape
MODELING THE TORSION-STRETCH COUPLING IN THE OH SPECTRUM OF cis-cis HOONO USING A THREE DIMENSIONAL POTENTIAL SURFACE
No full textAuthor Institution: Arthur Amos Noyes Laboratory for Chemical Physics, California Institute; of Technology, Pasadena, CA 91125; Department of Chemistry, The Ohio State University, Columbus, OH 43210; Arthur Amos Noyes Laboratory for Chemical Physics, California Institute; of Technology, Pasadena, CA 91125\maketitle The lowest energy conformer of HOONO, the \textit{cis-cis} isomer, forms a ring structure with an internal hydrogen bond. Because of this hydrogen bond, the OH stretch frequency and band intensity are dependent on the dihedral angles HOON and OONO. The torsional motions about these angles have comparable frequencies and are coupled. Previous calculations used two dimensional models that explicitly treated the OH stretch and the HOON torsion (rotation of the OH out of the ring plane)} \textbf{122}, 104311 (2005).}} \textbf{123}, 134318 (2005).}} \textbf{123}, 134318 (2005).}, or three dimensional models that also explicitly treat the OOH bond angle} \textbf{109}, 1810 (2005).}. These models were used to compute the 2D or 3D energies, and v transition intensities. In this work, we extended the previous 2D treatments in order to examine the importance of the remaining OONO torsional mode. The minimum energy path along the two dihedral angles of HOONO was computed at the CCSD(T)/cc-pVTZ level. The three dimensional potential energy surface was then computed as a function of the HOON and OONO dihedral angles, and of the OH bond length. Vibrational levels were obtained by solving the three dimensional Hamiltonian in the vibrationally adiabatic approximation. The potential surface shows coupling of the two torsional angles and the OH stretch. This coupling is harmonic at small torsional angles, and anharmonic at large torsional angles. The effects of the coupling on the torsional energy levels are compared to previous coupling treatments
The International Atomic Energy Agency International Doubly Labelled Water Database : Aims, Scope and Procedures
No full textFunding Sources The database is generously supported by the IAEA and by the companies Taiyo Nippon Sanso, SERCON and ISOTEC. We are grateful to these companies for their support and especially to Takashi Oono for his tremendous efforts at fund raising on our be half. The authors also gratefully acknowledge funding from the US National Science Foundation (BCS-1824466) awarded to Herman Pontzer. The funders played no role in the content of this manuscript. Open access provided with a grant from the International Atomic Energy Agency. Author Contributions All authors contributed to the drafting and editing of the manuscript and to construction of the IAEA DLW database.Peer reviewe
The Nonlinear World: Conceptual Analysis and Phenomenology
No full textThe most important characteristic of the “world filled with nonlinearity” is the existence of scale interference: disparate space–time scales interfere with each other. Thus, the effects of unknowable scales invade the world that we can observe directly. This leads to various peculiar phenomena such as chaos, critical phenomena, and complex biological phenomena, among others. Conceptual analysis and phenomenology are the keys to describe and understand phenomena that are subject to scale interference, because precise description of unfamiliar phenomena requires precise concepts and their phenomenological description. The book starts with an illustration of conceptual analysis in terms of chaos and randomness, and goes on to explain renormalization group philosophy as an approach to phenomenology. Then, abduction is outlined as a way to express what we have understood about the world. The book concludes with discussions on how we can approach genuinely complex phenomena, including biological phenomena. The main target of this volume is young people who have just started to appreciate the world seriously. The author also wishes the book to be helpful to those who have been observing the world, but who wish to appreciate it afresh from a different angle
Tensile properties of Co-based oxide dispersion strengthened superalloys
No full textTensile properties of a novel Co-20Cr-5Al-2.4Hf-1.5Y(2)O(3) (wt%) oxide dispersion strengthened (ODS) superalloy were studied through a comparing investigation with Co-20Cr-5Al (wt%) alloy. Both the Co-based alloys (with and without oxide particles) were fabricated by mechanical alloying (MA), spark plasma sintering (SPS), hot rolling and the final annealing at 1200 degrees C. Due to the ultrafine grains of 500 nm in the ODS superalloy and 1.2 mu m in the ODS free alloy, the metastable fcc structure predominates at room temperature. Tensile testing was conducted at room temperature and 1000 degrees C. Strain-induced twinning deformation was evidenced by transmission electron microscopy and was found to significantly enhance the ultimate tensile strength (UTS) of the two alloys at room temperature. The Co-based ODS superalloy exhibits a superior tensile strength of 2.85 GPa at room temperature, which is associated with the distribution of twins and fine Y-Hf oxides. At 1000 degrees C, since the ultrafine grain size in the ODS superalloys, an easy grain boundary deformation occurred and resulted in a significant reduction in the UTS value. (C) 2017 Elsevier B.V. All rights reserved
