Phonon emission from a discrete sine-Gordon breather

Phonon emission from a large-amplitude discrete sine-Gordon breather was studied numerically for a small degree of discreteness. In contrast to the case of highly discrete system investigated by Boesch and Peyrard (Phys. Rev. B 43 (1991) 8491), it was found that the resonance between the breather's oscillation and the phonons of the lower phonon band edge (κ=0) takes place for a small degree of discreteness.     

Tensile behaviour in 30Ni-30Cu-40Mn-based alloys for a dental application

It was possible to examine the tensile behaviour in experimental 30Ni-30Cu-40Mn-based alloys which were modified by alloying additions of aluminium, indium and tin. Namely, the experimental alloys were developed on the basis of crack formation in a commercial nickel-based alloy and microstructural features in nickel-based alloys investigated. The addition was done by substituting only the manganese content (40 wt%) to 35 and 40 wt%. The results indicated that both changes of tensile strength and elongation were obtained with castability values above 94%. Comparison of tensile properties in experimental Ni-Cu-Mn-based alloys studied here showed that the addition of aluminium to the alloys was appropriate to obtain results similar to those for commercial alloys, indicating that the refining of dendrite arm spacing was obtained by aluminium addition.     

Ethylene carbonate/ether solvents for electrolytes in lithium secondary batteries

An examination has been made of the effectiveness of ethylene carbonate(EC)/2-methyltetrahydrofuran(2-MeTHF) solvents incorporating LiAsF₆ as the solute as electrolytes in secondary lithium batteries. From —10 to 30 °C, the conductivities of EC/2-MeTHF are higher than those of 2-MeTHF and EC/propylene carbonate (PC). For lithium-on-lithium cycling in a half cell, the FOM (figure of merit) of lithium in EC/2-MeTHF has a value 2.2 to 2.7 times higher than that in 2-MeTHF and EC/PC. A coin cell of Li/amorphous V₂O ₅-P₂O₅ with EC/2-MeTHF clearly exhibits higher capacity and longer cycle life than cells with 2-MeTHF or EC/PC. It is concluded that EC/2-MeTHF is a promising electrolyte system for secondary lithium battery applications.     

Denture base materials reinforced with glass fibres

Glass fibres for industrial use were laid on denture base materials such as self-curing and heat-curing resins to reinforce them. The use of heat-curing rather than self-curing resin as a base resin indicated a superior effect on bending properties.     

Robust digital control of a DC–DC buck converter with low frequency samplings

A robust DC?CDC converter which can covers extensive load change and also input voltage changes with one controller is needed. Then the demand to suppress output voltage change becomes still severer. We propose an approximate 2-degree-of-freedom (2DOF) digital controller which realized start-up response and dynamic load response independently. The controller makes a control bandwidth wider, and at the same time makes variations of the output voltage small at sudden changes of a load and an input voltage. In this paper, a new approximate 2DOF digital control system with additional zeros is proposed. Using the additional zeros, the second-order differential transfer characteristics between equivalent disturbances and a output voltage are realized. Therefore, the new controller makes variations of the output voltage smaller and the sudden changes of the load and the input voltage. This controller is actually implement on a DSP and is connected to the DC?CDC converter. Experimental results demonstrate that this type of digital controller can satisfy given severe specifications with low frequency sampling.     

Effect of filler content on mechanical strength in bis-GMA-based resins with urethane linkages

Bis-GMA-based visible-light-cured resins containing urethane linkages exhibited improved hardness and strength by addition of filler to the unfilled resins. The urethane monomers in the resins strengthened the resin matrix, exhibiting an increased Shore hardness value. Urethane monomer derived from 2HEMA and N3500 was more effective than that from 2HEMA and HT. The increased strength in the resin matrix occurred after storage in water at 37°C. Addition of filler to bis-GMA-based resins increased compressive strength (110 MPa as the maximum), while diametral strength values of 20 MPa were obtained.     

Thermoanalytical characteristics of powders in dental cast investment

The present study examined the thermal properties of phosphate-bonded investments, a gypsum-bonded investment and an experimental investment powder when the basic powders were heated to high temperatures by simultaneous differential thermal analysis (DTA) and thermogravimetry (TG). The phosphate-bonded investments showed values of about 59 kcal mol^–1 (247 kJ mol^–1) (thermal decomposition of NH₄H₂PO₄) and about 11 kcal mol^–1 (46 kJ mol^–1) (formation of NH₄MgPO₄). Thermal reactions occurred clearly on the DTA-TG curves for the investment powders, using powders of NH₄H₂PO₄, and MgO with NH₄H₂PO₄/MgO = 1 as main components in the investment.     

Selective Patterning of Gold Surfaces by Core/Shell,Semisoft Hybrid Nanoparticles

The generation of patterned surfaces with well‐defined nano‐ and microdomains is demonstrated by attaching core/shell, semisoft nanoparticles with narrow size distribution to microdomains of a gold‐coated silicon wafer. Near monodisperse nanoparticles are prepared using reversible addition‐fragmentation chain transfer (RAFT) polymerization, initiated from a silica surface, to prepare a polystyrene shell around a silica core. The particles are then used as‐prepared, or after aminolysis of the terminal thiocarbonyl group of the polystyrene shell, to give thiol‐terminated nanoparticles. When gold‐coated silicon wafers are immersed into very dilute suspensions of these particles (as low as 0.004 wt%), both types of particles are shown to adhere to the gold domains. The thiolated particles adhere selectively to the gold microdomains, allowing for microdomain patterning, while particles that contain the trithiocarbonate functionality lead to a much more even coverage of the gold surface with fewer particle aggregations.     

Dynamics of autowaves in a one-dimensional crystal model

A mechanism of the phase transition between two modulated structures with different wave vectors was proposed and investigated numerically. The phase transition occurs through the mechanism of nucleation and growth of the new phase. The role of the nucleus is played by an unstable domain wall and the domain of a new low energy phase grows due to the motion of autowaves.