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Microstructural Analysis Of Insoluble Polyolefins By Melt-State13c Nmr At Very High Temperatures, Toshikazu Miyoshi
Microstructural Analysis Of Insoluble Polyolefins By Melt-State13c Nmr At Very High Temperatures, Toshikazu Miyoshi
Toshikazu Miyoshi
No abstract provided.
Dynamic Geometry And Kinetics Of Polymer Confined In Self-Assembly Via Cooperative Hydrogen Bonding: A Solid-State Nmr Study Under Paramagnetic Doping, Toshikazu Miyoshi
Dynamic Geometry And Kinetics Of Polymer Confined In Self-Assembly Via Cooperative Hydrogen Bonding: A Solid-State Nmr Study Under Paramagnetic Doping, Toshikazu Miyoshi
Toshikazu Miyoshi
No abstract provided.
Slow Chain Dynamics In Isotactic-Poly (4-Methyl-1-Pentene) Crystallites Near The Glass Transition Temperature Characterized By Solid-State 13c Mas Exchange Nmr, Toshikazu Miyoshi
Slow Chain Dynamics In Isotactic-Poly (4-Methyl-1-Pentene) Crystallites Near The Glass Transition Temperature Characterized By Solid-State 13c Mas Exchange Nmr, Toshikazu Miyoshi
Toshikazu Miyoshi
The chain dynamics for isotactic-poly(4-methyl-1-pentene) (iP4M1P) crystallites near the glass transition temperature (Tg = 304 K) is characterized by solid-state 13C MAS NMR methods at natural abundance. The 13C line width under high-power proton decoupling and the 13C spin−lattice relaxation time in the rotating frame (T1ρc) detect the segmental motions in the amorphous and crystalline regions with correlation times of about 0.2 × 10-5 s at 360−382 K and about 448 K, respectively. Centerband-only detection of exchange (CODEX) with an additional T1ρc filter is applied to investigate the motional geometry and kinetic parameters for the main- and side-chain dynamics in …
Slow Dynamics Of Polymer Crystallites Revealed By Solid-State Mas Exchange Nmr, Toshikazu Miyoshi
Slow Dynamics Of Polymer Crystallites Revealed By Solid-State Mas Exchange Nmr, Toshikazu Miyoshi
Toshikazu Miyoshi
No abstract provided.
Molecular Ordering And Molecular Dynamics In Isotactic-Polypropylene Characterized By Solid State Nmr, Toshikazu Miyoshi
Molecular Ordering And Molecular Dynamics In Isotactic-Polypropylene Characterized By Solid State Nmr, Toshikazu Miyoshi
Toshikazu Miyoshi
The order−disorder phenomenon of local packing structures, space heterogeneity, and molecular dynamics and average lamellar thickness, , of the α form of isotactic polypropylene (iPP) crystallized at various supercooling temperatures, ΔT, are investigated by solid-state (SS) NMR and SAXS, respectively. increases with lowering ΔT, and extrapolations of −1 versus averaged melting point, , gives an equilibrium melting temperature, Tm0 = 457 ± 4 K. High-power TPPM decoupling with a field strength of 110 kHz extremely improves 13C high-resolution SS-NMR spectral resolution of the ordered crystalline signals at various ΔT. A high-resolution 13C SS-NMR spectrum combined with a conventional spin−lattice relaxation …
Formation Of Crosslinked Ptfe By Radiation-Induced Solid-State Polymerization Of Tetrafluoroethylene At Low Temperatures, Toshikazu Miyoshi
Formation Of Crosslinked Ptfe By Radiation-Induced Solid-State Polymerization Of Tetrafluoroethylene At Low Temperatures, Toshikazu Miyoshi
Toshikazu Miyoshi
Tetrafluoroethylene monomer (TFE) was polymerized with gamma rays at various temperatures. The thermal properties of product were measured by using a differential scanning calorimeter (DSC) and the structure was analyzed by means of 19F high speed magic angle spinning nuclear magnetic resonance (19F NMR). It was found that, the PTFE obtained by the solid-state polymerization has been made clear to be crosslinked.
Chemical Characteristics Of Dissolved Organic Matter In An Oligotrophic Subtropical Wetland/Estuarine Ecosystem, Toshikazu Miyoshi
Chemical Characteristics Of Dissolved Organic Matter In An Oligotrophic Subtropical Wetland/Estuarine Ecosystem, Toshikazu Miyoshi
Toshikazu Miyoshi
Fluorescence properties of whole water samples and molecular characteristics of ultrafiltrated dissolved organic matter (UDOM 1,000 D) such as lignin phenol and neutral sugar compositions and 13 C nuclear magnetic resonance (NMR) spectra were determined along a freshwater to marine gradient in Everglades National Park. Furthermore, UDOM samples were categorized by hierarchical cluster analysis based on their pyrolysis gas chromatography/mass spectrometry products. Fluorescence properties suggest that autochthonous DOM leached/exuded from biomass is quantitatively important in this system. 13 C NMR spectra showed that UDOM from the oligotrophic Taylor Slough (TS) and Florida Bay (FB) ecosystems has low aromatic C (13% …
Chain Folding In Polymer Crystals Detected By Solid-State Nmr, Toshikazu Miyoshi
Chain Folding In Polymer Crystals Detected By Solid-State Nmr, Toshikazu Miyoshi
Toshikazu Miyoshi
Polymer crystallization induces transitions from random coils in the melt states to bilayer structures consisting of chain-folded crystals and disordered amorphous regions. Although the concept of chain folding is well recognized, there have been continuous debates about adjacent re-entry fractions of polymer chains crystallized at different physical conditions. To understand chain-folding structures in complex systems, spatial selectivity to access short-range polymer-polymer interactions is necessary. In this talk, we will propose a novel approach using solid-state NMR and selective isotope labeling for characterizing chain-folding of polymer chains. Spatial selectivity in double quantum NMR reveals adjacent re-entry fractions in the bulk crystals …
Dynamics Property Of Poly (3-Methyl-1-Butene) Characterized By Solid-State Nmr And Dma, Toshikazu Miyoshi
Dynamics Property Of Poly (3-Methyl-1-Butene) Characterized By Solid-State Nmr And Dma, Toshikazu Miyoshi
Toshikazu Miyoshi
No abstract provided.
Development Of Active Filter With Mos-Fet For 15 Mw Dc Power Source, Toshikazu Miyoshi
Development Of Active Filter With Mos-Fet For 15 Mw Dc Power Source, Toshikazu Miyoshi
Toshikazu Miyoshi
A MOS-FET dropper was developed in place of a transformer coupled regulator in the active filter system of the 15 MW DC power supply to reduce the fluctuation to be lower than 10ppm at the Tsukuba Magnet Laboratory, National Institute for Materials Science.
Fast Dynamics And Conformations Of Polymer In A Conformational Disordered Crystal Characterized By H-1-C-13 Wise Nmr, Toshikazu Miyoshi
Fast Dynamics And Conformations Of Polymer In A Conformational Disordered Crystal Characterized By H-1-C-13 Wise Nmr, Toshikazu Miyoshi
Toshikazu Miyoshi
No abstract provided.
Large-Amplitude Motions Of Form Iii Of Isotactic Poly (4-Methyl-1-Pentene) Crystallites Prior To Crystal-Crystal Transformation, Toshikazu Miyoshi
Large-Amplitude Motions Of Form Iii Of Isotactic Poly (4-Methyl-1-Pentene) Crystallites Prior To Crystal-Crystal Transformation, Toshikazu Miyoshi
Toshikazu Miyoshi
No abstract provided.
Self-Assembly Of The Mesoporous Electrode Material Li3fe2 (Po4) 3 Using A Cationic Surfactant As The Template, Toshikazu Miyoshi
Self-Assembly Of The Mesoporous Electrode Material Li3fe2 (Po4) 3 Using A Cationic Surfactant As The Template, Toshikazu Miyoshi
Toshikazu Miyoshi
Mesoporous Li3Fe2(PO4)3 battery electrode materials (see Figure) with a discharge capacity of 140 mAh g–1 at 20 mA g–1 self-assemble under aqueous conditions using a cationic surfactant as the template. Mössbauer spectroscopy results are characteristic of Fe3+ ions in oxides, while the interaction of lithium with Fe and O in mesoporous Li3Fe2-(PO4)3 is verified by 7Li NMR. This synthetic strategy may be applied to the production of other multi-metal phosphate ordered mesoporous structures.
Dynamics Aspect Of Supramolecular Peo-Urea Crystal Revealed By Solid-State'13'C Mas Nmr, Toshikazu Miyoshi
Dynamics Aspect Of Supramolecular Peo-Urea Crystal Revealed By Solid-State'13'C Mas Nmr, Toshikazu Miyoshi
Toshikazu Miyoshi
No abstract provided.
Radiation-Induced Synthesis Of Low Molecular Weight Of Ptfe And Their Crosslinking In Acetone Medium, Toshikazu Miyoshi
Radiation-Induced Synthesis Of Low Molecular Weight Of Ptfe And Their Crosslinking In Acetone Medium, Toshikazu Miyoshi
Toshikazu Miyoshi
Polytetrafluoroethylene was obtained by radiation-induced polymerization of tetrafluoroethylene in acetone at 195 K. An average diameter of the products was very small compared with the commercial one; it was about 0.2 μm. The yield was reached to 100% with a dose of 4 kGy. The crystallinity of the products is decreasing with increasing dose. The crystallinity becomes low, for higher irradiation doses. It was found that PTFE obtained by irradiation of TFE in acetone at 195 K has Y-type crosslinking structure. This was demonstrated by means of 19F MAS NMR.
Solid-State Nmr Characterization Of Polymer Materials, Toshikazu Miyoshi
Solid-State Nmr Characterization Of Polymer Materials, Toshikazu Miyoshi
Toshikazu Miyoshi
No abstract provided.
Chain Packing And Trajectory Of Isotactic Polypropylene $$Backslash$ Alpha $ Crystals Studied By Solid-State Nmr, Toshikazu Miyoshi
Chain Packing And Trajectory Of Isotactic Polypropylene $$Backslash$ Alpha $ Crystals Studied By Solid-State Nmr, Toshikazu Miyoshi
Toshikazu Miyoshi
No abstract provided.
Local Packing Disorders In A Polymer Crystal By Two Dimensional Solid-State Nmr, Toshikazu Miyoshi
Local Packing Disorders In A Polymer Crystal By Two Dimensional Solid-State Nmr, Toshikazu Miyoshi
Toshikazu Miyoshi
No abstract provided.
Molecular Motions Of Crystalline Polymers By Solid-State Mas Nmr, Toshikazu Miyoshi
Molecular Motions Of Crystalline Polymers By Solid-State Mas Nmr, Toshikazu Miyoshi
Toshikazu Miyoshi
Chain dynamics in the crystalline region of semicrystalline polymers play an important role for bulk material properties such as mechanical strength, creep, drawability, crystallization process, and crystal transformation. Therefore, it is important to characterize chain dynamics in detail. 2D exchange NMR is a reliable tool for polymer dynamics analysis, because this method provides motional geometry and time-kinetic parameters quantitively. However, it is difficult to apply this sophisticated method for polymers with chemically complicated polymers in natural abundance. ID-MAS exchange NMR method is possible to give the same information, and has a great advantage of characterizing molecular dynamics for multi-functional groups …
Quantitative And Qualitative Aspects Of Dissolved Organic Carbon Leached From Senescent Plants In An Oligotrophic Wetland, Toshikazu Miyoshi
Quantitative And Qualitative Aspects Of Dissolved Organic Carbon Leached From Senescent Plants In An Oligotrophic Wetland, Toshikazu Miyoshi
Toshikazu Miyoshi
We conducted a series of experiments whereby dissolved organic matter (DOM) was leached from various wetland and estuarine plants, namely sawgrass (Cladium jamaicense), spikerush (Eleocharis cellulosa), red mangrove (Rhizophora mangle), cattail (Typha domingensis), periphyton (dry and wet mat), and a seagrass (turtle grass; Thalassia testudinum). All are abundant in the Florida Coastal Everglades (FCE) except for cattail, but this species has a potential to proliferate in this environment. Senescent plant samples were immersed into ultrapure water with and without addition of 0.1% NaN3 (w/ and w/o NaN3, respectively) for 36 days. We replaced the water every 3 days. The amount …