Preparation of Mn-Co-Ni mono-phase spinel oxide by oxidation of rock salt-type oxide

Preparation of a mono-phase spinel from a ternary system Mn-Co-Ni oxide with a molar ratio of 3.01.91.1 was investigated. It was found that the oxidation profile of a rock salt-type oxide, which was formed at 1400 °C, was the most significant factor. As a result, the perfect mono-phase specimen was obtained by water quenching the rock salt-type oxide and then heat treating to oxidize it for more than 3 h at 1000°C.     

Numerical plate testing for linear two‐scale analyses of composite plates with in‐plane periodicity

A method of numerical plate testing (NPT) for composite plates with in‐plane periodic heterogeneity is proposed. In the two‐scale boundary value problem, a thick plate model is employed at macroscale, while three‐dimensional solids are assumed at microscale. The NPT, which is nothing more or less than the homogenization analysis, is in fact a series of microscopic analyses on a unit cell that evaluates the macroscopic plate stiffnesses. The specific functional forms of microscopic displacements are originally presented so that the relationship between the macroscopic resultant stresses/moments and strains/curvatures to be consistent with the microscopic equilibrated state. In order to perform NPT by using general‐purpose FEM programs, we introduce control nodes to facilitate the multiple‐point constraints for in‐plane periodicity. Numerical examples are presented to verify that the proposed method of NPT reproduces the plate stiffnesses in classical plate and laminate theories. We also perform a series of homogenization, macroscopic, and localization analyses for an in‐plane heterogeneous composite plate to demonstrate the performance of the proposed method. Copyright © 2015 John Wiley & Sons, Ltd.     

An Efficient Boundary Handling with a Modified Density Calculation for SPH

We propose a new boundary handling method for smoothed particle hydrodynamics (SPH). Previous approaches required the use of boundary particles to prevent particles from sticking to the boundary. We address this issue by correcting the fundamental equations of SPH with the integration of a kernel function. Our approach is able to directly handle triangle mesh boundaries without the need for boundary particles. We also show how our approach can be integrated into a position‐based fluid framework.     

High Mobility WS2 Transistors Realized by Multilayer Graphene Electrodes and Application to High Responsivity Flexible Photodetectors

The electrical contact is one of the main issues preventing semiconducting 2D materials to fulfill their potential in electronic and optoelectronic devices. To overcome this problem, a new approach is developed here that uses chemical vapor deposition grown multilayer graphene (MLG) sheets as flexible electrodes for WS₂ field‐effect transistors. The gate‐tunable Fermi level, van der Waals interaction with the WS₂, and the high electrical conductivity of MLG significantly improve the overall performance of the devices. The carrier mobility of single‐layer WS₂ increases about a tenfold (50 cm² V^?1 s^?1 at room temperature) by replacing conventional Ti/Au metal electrodes (5 cm² V^?1 s^?1) with the MLG electrodes. Further, by replacing the conventional SiO₂ substrate with a thin (1 µm) parylene‐C flexible film as insulator, flexible WS₂ photodetectors that are able to sustain multiple bending stress tests without significant performance degradation are realized. The flexible photodetectors exhibited extraordinarily high gate‐tunable photoresponsivities, reaching values of 4500 A W^?1, and with very short (<2 ms) response time. The work of the heterostacked structure combining WS₂, graphene, and the very thin polymer film will find applications in various flexible electronics, such as wearable high‐performance optoelectronics devices.     

Asymmetric polymerization of N-substituted maleimides with organolithium — bisoxazolines complex

Asymmetric anionic polymerizations of achiral N-substituted maleimide (RMI) (N-cyclohexyl (CHMI), N-phenyl (PhMI), N-tert-butyl (TBMI)) by n-butyllithium (n-BuLi) or fluorenyllithium (FlLi) complexes of chiral bisoxazoline derivatives in toluene gave optically active polymers ([α]²⁵ ₄₃₅− 2.9° to − 8.2°). The polymers prerared with initiator of n-BuLi – 2,2′-bis(4,4′-isopropyl-,3-oxazoline) showed negative specific rotations (poly(RMI), [α]²⁵ ₄₃₅− 5.8° to − 8.2°) which were greater than those ([α]²⁵ ₄₃₅− 2.9° to − 5.9°) with other chiral 2,2′-bis(4,4′-alkyl-1,3-oxazoline) (alkyl group = iso-butyl and benzyl). Received: 29 July 1997/Revised: 27 August 1997/Accepted: 1 September 1997     

Syntheses of chemical‐modified cellulose obtained from waste pulp

Chemical‐modified pulps were synthesized from four types of waste pulps (Pulp1–4) and succinic anhydride (SAn) or maleic anhydride (MAn). The solubility of the modified pulps was evaluated in common organic solvents, and their thermal properties were investigated by DSC measurement. The solubility of the modified pulps increased with an increasing degree of substitution (DS). However, no T_g or T_m of these modified pulps was confirmed. Pulps and modified pulps were graft‐polymerized with ε‐caprolactone (CL) in bulk and in DMAc/LiCl. Although the solubility of the graft copolymers was similar to modified pulps, some graft copolymers showed a T_g by the introduction of CL units. In the bulk, graft copolymers obtained from modified pulps and nonmodified pulps showed a T_g of about 75°C and no T_g, respectively. In DMAc/LiCl, the obtained graft copolymers from both modified and nonmodified pulps exhibited a T_g of 95–110°C. © 2003 Wiley Periodicals, Inc. J Appl Polym Sci 90: 2059–2065, 2003     

Carbonization properties of hydrogenated aromatic hydrocarbons—III: Modifying activities of hydrogenated pryene and its oxidized derivatives in the co-carbonization of coals and coal liquids

The modifying activities of hydrogenated pyrene (HP) and its oxidized derivatives were examined in co-carbonization with solvent refined coal, solvent treated coal, a fusible and a non-fusible coal. The present additives all showed a significant activity, with HP oxidized at 150°C exhibiting the highest activity. The activity of the additive is discussed from its structural indices and coke yield in relation to its dissolving and hydrogen donating abilities. The modifying susceptivility of the carbonizing substance is rated in the order described above, being correlated with its single carbonization properties, such as fusibility and potential for anisotropic development. A consecutive treatment of partial hydrogenation and oxidation is emphasized as a useful technique for producing active additive and an excellent coking substance from the pitch material.     

Carbonization of pitch: Compatibility of components in carbonization

The carbonization of four kinds of solvent-refined-coal (SRC) pitches was investigated in order to determine the properties required for the formation of needle coke. Although the pitches were free from Ql materials, two of them gave needle cokes, whereas the other two gave mosaic cokes. The BS fractions of all pitches formed needle cokes, and all Bl fractions were infusible and isotropic. A combination of suitable BS and Bl fractions gave a needle coke, whereas another mixture formed a mosaic coke, indicating that the BS and the Bl fractions can be compatible to yield a needle coke. Cocarbonization of the BS fractions from other pitch sources with the Bl from the SRC pitches was further studied to evaluate the compatibility, which has been discussed from the structural viewpoint. Trials to improve the properties were proposed, based on the structural information.     

Syntheses and biodegradability of benzylated waste pulps and graft copolymers from PBzs and L‐lactic acid

Benzylated waste pulps (PBzs) were synthesized from treated waste pulp (Pulp), and benzyl chloride with phase transfer catalyst (PTC), and graft copolymers (PBz‐g‐LA) were synthesized from PBzs and L‐lactic acid (LA). Thermal properties, solubility, crystallinity, and biodegradability of the obtained PBzs and graft copolymers were investigated. PBzs with the degree of substitution (DS) higher than 1.5 showed T_g and T_m in DSC measurement. All PBz‐g‐LA exhibited no T_m. However, the graft copolymers obtained from lower DS PBzs having no T_g, exhibited T_g. The solubility of PBzs enhanced with increasing DS, and the crystallinity of PBzs reduced with increasing DS because of hydrophobicity and steric effect of benzyl groups. The solubility of graft copolymers was similar to that of original PBzs. Biodegradation tests for PBzs, Pulp, and graft copolymers were performed using cellulase in 0.1 M acetate buffer solution (pH 5.5) at 37°C. All samples showed biodegradability though the biodegradation rate decreased with increasing DS of PBz. In PBz‐g‐LA, the initial biodegradation rate was faster than that of original PBz because of hydrolysis of LA units. © 2004 Wiley Periodicals, Inc. J Appl Polym Sci 92: 2658–2664, 2004