Size-dependent inclusion of organic molecules into elastic pillared carbons

Size selective inclusion of organic molecules into pillared carbons accompanied by large interlayer expansions was observed for the first time. In order to achieve this, the distance between two adjacent pillars should be between 0.36 and 0.40 nm and they should align in the same direction.     

Polynomial solutions of q-Heun equation and ultradiscrete limit

We study polynomial-type solutions of the q-Heun equation, which is related with quasi-exact solvability. The condition that the q-Heun equation has a non-zero polynomial-type solution is described by the roots of the spectral polynomial, whose variable is the accessory parameter E. We obtain sufficient conditions that the roots of the spectral polynomial are all real and distinct. We consider the ultradiscrete limit to clarify the roots of the spectral polynomial and the zeros of the polynomial-type solution of the q-Heun equation.     

In situ measurement of crystallization of oxide thin films during irradiation with pulsed UV laser in chemical solution deposition process

The epitaxial and polycrystalline growth of lanthanum strontium manganite films on single crystalline strontium titanate and lanthanum aluminate substrates, respectively, under the irradiation with XeCl lasers in the excimer laser-assisted metal organic deposition (ELAMOD) process have been previously reported. In order to investigate the growth phenomena, we monitored the thermal radiation from the sample surfaces irradiated with a pulsed ultraviolet laser in situ with near-infrared sensors. The cooling of the lanthanum strontium manganite films on strontium titanate substrates was significantly slower than that of films on lanthanum aluminate substrates. A similar behavior was also observed by the numerical simulation study. This difference in the cooling decay curves may play an important role in the mode by which crystal growth occurs in the ELAMOD process.     

Synthesis of well‐defined polymers end‐functionalized with crosslinkable aziridine groups by living anionic polymerization

Well‐defined end‐functionalized polystyrene, poly(α‐methylstyrene), and polyisoprene with polymerizable aziridine groups were synthesized by the termination reactions of the anionic living polymers of styrene, α‐methylstyrene, and isoprene with 1‐[2‐(4‐chlorobutoxy)ethyl]aziridine in tetrahydrofuran at ?78 °C. The resulting polymers possessed the predicted molecular weights and narrow molecular weight distributions (weight‐average molecular weight/number‐average molecular weight < 1.1) as well as aziridine terminal moieties. The cationic ring‐opening polymerization of the ω‐monofunctionalized polystyrene having an aziridinyl group with Et₃OBF₄ gave the polymacromonomer, whereas the α,ω‐difunctional polystyrene underwent crosslinking reactions to afford an insoluble gel. Crosslinking products were similarly obtained by the reaction of the α,ω‐diaziridinyl polystyrene with poly(acrylic acid)‐co‐poly(butyl acrylate). © 2005 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 43: 4126–4135, 2005     

Influence of the loading rate on liquid‐crystalline epoxy resin systems

The fracture toughness of liquid‐crystalline epoxy systems, which had a nematic polydomain structure (domain size about 40 μm), with an increasing loading rate was evaluated. In this system, the fracture toughness dramatically decreased from 1.96 to 0.22 MN/m^3/2 with an increasing loading rate (0.1–5 mm/min). The network orientation near the fracture surface of different loading rate systems was investigated with polarized optical microscopy and polarized infrared spectroscopy. As a result, a large oriented region of mesogenic groups was observed near the fracture surface in the relatively low loading rate (0.1 and 0.5 mm/min) systems, but such a phenomenon was not observed in the high loading rate (2 and 5 mm/min) systems. These results showed that the high fracture toughness of the system at the low loading rate was due to the magnitude and region of the reorientation of the mesogenic groups in the fracture process and that high toughness could not be achieved at a high loading rate because the loading rate was too fast to allow orientation of the networks containing the mesogenic groups. © 2005 Wiley Periodicals, Inc. J Polym Sci Part B: Polym Phys 43: 1296–1302, 2005     

Synthesis of polyester dendrimers and dendrons starting from Michael reaction of acrylates with 3-hydroxyacetophenone

A new AB₂ type building block for synthesis of dendritic compounds is made starting from Michael addition of 2 equiv of 3-hydroxyacetophenone to acrylate, followed by decarboxylation and deprotection of either carboxyl or hydroxyl protecting groups. [G1]-[G4] dendrons and [G2] dendrimer were synthesized by the reiterative [hydrogenolysis then DCC/DPTS coupling] sequence using a combination of convergent and divergent growth methods.     

Separation of microamounts of fluoride coexisting with large amounts of aluminium and silica by improved trimethylsilylating distillation

The previously reported distillation method for the separation of fluoride as trimethyl- fluorosilane is much improved. When hexamethyldisilazane serves as the silylating agent, interference of silica can be avoided and distillation is rapid at room temperature. Aluminum is effectively masked by pyrophosphoric acid. Almost all ions tested can be tolerated in 1000-fold molar amounts to fluoride. Over 98% recovery is obtained for 49 μg of fluoride in the presence of 80 mg of aluminum plus 200 mg of silica. Concentration of fluoride from very dilute (μg l^-1) solutions is easily achieved. Satisfactory results were obtained for standard rocks.     

Tunneling time based on the quantum diffusion process approach in multichannel and optical potential cases

We analyze the effects of inelastic scattering on the tunneling time theoretically, using generalized Nelson’s quantum mechanics. This generalization enables us to describe quantum system with channel couplings and optical potential in a real time stochastic approach, which seems to give us a new insight into quantum mechanics beyond Copenhagen interpretation