Dynamical observation of structural transition of polymers using an X‐ray diffraction system with imaging plates. II. Crystalline transition of poly(butylene terephthalate)

Poly(butylene terephthalate) has two crystalline forms of α and β. The α form is more stable and is transformed into the β form by stretching. The α↔β transition stress was measured at various temperatures with the use of an X‐ray diffraction system with imaging plates, and the relationship between the transition stress and temperature was obtained. Further, using the X‐ray diffraction system, the drawing behavior of the nearly amorphous, undrawn polymer film was observed by taking up dynamically a series of X‐ray diffraction patterns while a film was being drawn. The α form never occurred during drawing at any temperature because the stress to draw the film exceeded the α→β transition stress. © 2000 John Wiley & Sons, Inc. J Polym Sci B: Polym Phys 38: 838–845, 2000     

Total Synthesis of Terprenin,a Highly Potent and Novel Immunoglobulin E Antibody Suppressant

Regioselective halogenations and Suzuki reactions ensure proper linkage of the aromatic rings in two total syntheses of terprenin ( 1 ). Both routes make it possible to prepare 1 efficiently and in large quantity.     

Exploring novel poly(thiophene‐3‐yl‐amine) through facile self acid assisted‐polycondensation

Aromatic moieties of benzene and pyridine as side chains for poly(thiophene‐3‐yl‐amine) are rationally designed and synthesized by facile self acid‐assisted polycondensation (SAAP). Nitrogen atom is the key atom to form ammonium cation which guarantees SAAP success while other aromatic moieties are chosen carefully to attach on N atom to functionalize poly(thiophene‐3‐yl‐amine) matrix. Our results indicate that thiophene‐3‐yl‐amine is an excellent platform to construct plenty of functionalized monomers candidates for SAAP. Our study would push SAAP or AAP scope forward and pave the way to explore much more polythiophene derivatives. Furthermore, DFT calculation is carried out to deep understand AAP mechanism. © 2017 Wiley Periodicals, Inc. J. Polym. Sci., Part A: Polym. Chem. 2017 , 55, 4003–4012     

Cluster fluctuation in two-dimensional lattices with local interactions

It is known that under the local interactions of agents, we find cluster formations of states of agents, but few works exist on the changes (fluctuations) of clusters. This paper deals with the analysis of fluctuations of clusters with respect to states of agents placed on two-dimensional lattices having local interactions. We use two models; first we use Model S that consists of agents producing goods, whose states denote the activity of agents, as well as the accompanying multiple states. An agent decides the states in the subsequent time period by monitoring the states of neighboring agents. Then, we introduce Model P to cope with cases that are more realistic. In Model P, we assume that there exists a group of agents comprising a pool of labor agents and several firm agents collaborating in production, where the labor agents are free to move neighborhoods seeking better incomes. We find cluster formation and equilibrium in both models after the passage of time, but these cluster formations deform and become other formations by changing certain states of agents into random states, or by changing parameters to be random. In simulation studies, we show the conditions for the fluctuations of clusters and possible real applications.     

Molecular dynamics simulation of the pressure-induced phase transition in BaFCl

The structural phase transition in BaFCl under high-pressure up to 30 v GPa has been studied using molecular dynamics (MD) method. It was found that BaFCl transforms from a tetragonal structure to a monoclinic structure in the upstroke process and then the tetragonal structure is recovered upon releasing the pressure. The atomistic mechanisms of the transformation have been examined using the pair-correlation functions and the coordination numbers for the lattices with or without vacancies in the MD cell. It was also demonstrated that the Cl atoms between the adjacent weakly bonded Cl layers shift in the compressed direction and move to positions with a 2-fold coordination number at a nearest-neighbour site after the transition.     

Preparation of nano-sized YAG:Eu3+ particles by a microwave-assisted polyol process and their luminescence properties

Phases of yttrium-aluminum binary oxide have been selectively prepared by selecting a polyol solvent in a microwave-assisted polyol process. Using 1,4-butanediol as a polyol solvent, nano-sized particles of a pure phase of YAG have been prepared. Furthermore, Eu³⁺-doped YAG has been synthesized by applying this method. We have demonstrated that 8 at% Eu³⁺-doped YAG (replacement of Y³⁺) gave the strongest emission when the content of Eu³⁺ was varied.     

Simulation of the nonlinear vibration of a string using the cellular automation method

In this study, the nonlinear dynamic responses of a string were simulated using the cellular automaton (CA) method. The local rules were set for the amplitude of vibration and the decay rate of amplitude. In the case of nonlinear systems, the velocity of wave propagation is not constant and depends on the amplitude. Thus, a new treatment of the time step was proposed, i.e., the time step in the CA method is adjusted to real time by considering the effect of the propagation velocity. As numerical examples, first, the dynamic responses of a string with linear characteristic were simulated and a typical resonance curve could be obtained. Secondly the dynamic responses of a string with nonlinear characteristic were simulated. Some characteristic types of vibration could be obtained. It was concluded that the linear and nonlinear dynamic responses of a string could be simulated using the CA method.