Effect of molecular structure of phenolic resin on solder dip resistance and peel strength of printed circuit adhesives

Phenolic resins were synthesized by using various kinds and amounts of catalyst and changing the mole ration of formaldehyde and phenol. The solder dip resistance and the peel strength were measured for two-component printed circuit adhesives mixed with poly(vinyl acetal) resin, and the relation between these properties and the molecular structure of the phenolic resins were studied. Catalysts such as ammonia, amines having low boiling points, and alkaline earth metal oxide and hydroxides give resins with good properties. When the mole ratios of ammonia to phenol and formaldehyde to phenol are respectively 0.05–0.10 and 1.5, the resins obtained have good characteristics. The solder dip resistance is improved by aging the resin solution at moderate temperature.     

Mechanical properties and superstructure of high-modulus and high-strength nylon-6 fibre prepared by the zone-annealing method

The relationships between mechanical properties and superstructure of nylon-6 fibre prepared by a new annealing method, called the zone-annealing method, were investigated in comparison with three other annealing methods, namely, annealing under release, annealing at constant length, and annealing under tension. It was found that the very high modulus and strength of the zone-annealed fibre were directly attributed to the large number of tie molecules connecting the crystallites and to the high orientation of the amorphous chains.     

Prediction of the excess enthalpies of mixing of mixtures using the UNIFAC method

The UNIFAC model, developed for binary systems alkanes with n-alcohols, ketones, esters and ethers, and for ternary n-alcohol—n-alcohol—n-alkane systems, gives satisfactory predictions of excess enthalpies of mixing for the systems studied.     

Electron transport in Si nanochains/nanowires

Electronic transport properties of a bundle of Si nanochains/nanowires were investigated. Si nanochains and nanowires were grown via a self-organized vapor-liquid-solid process and located on a pair of electrodes with a gap of several hundred nanometers. Unstable and a variety of current-voltage (I-V) characteristics were observed and some of those were Coulomb staircase-like. In addition, fluctuations which were seemingly random but partly and partially reproducible were observed in I-V curves of a parallel junction of a nanochain and a nanowire.     

Stable expression and characterization of human PN1 and PN3 sodium channels

Nociceptive transduction in inflammatory and neuropathic pain involves peripherally expressed voltage-gated sodium channels, such as tetrodotoxin (TTX)-sensitive PN1 and TTX-resistant PN3. We generated recombinant cell lines stably expressing the human PN1 and PN3 sodium channels in Chinese hamster ovary (CHO) cells using inducible expression vectors. The PN1 and PN3 cDNAs were isolated from human adrenal gland and heart poly(A)+ RNAs, respectively. The recombinant human PN1 currents exhibited rapid activation and inactivation kinetics and were blocked by TTX with a half-maximal inhibitory concentration (IC50) of 32.6 nM. The human PN3 channel expressed in stable transfectants showed TTX-resistant inward currents with slow inactivation kinetics. The IC50 value for TTX was 73.3 microM. The voltage-dependence of activation of the PN3 channel was shifted to the depolarizing direction, compared to that of the PN1 channel. Lidocaine and mexiletine exhibited tonic and use-dependent block of PN1 and PN3 channels. The PN1 channel was more susceptible to inhibition by mexiletine than PN3. These results suggest that stable transfectants expressing the human PN1 and PN3 sodium channels will be useful tools to define subtype selectivity for sodium channel blockers.     

Nanodiamond Glass with Rubber Bond in Natural Rubber

Nanodiamond glass is an amorphous solid consisting of nanodiamond as a nanoparticle. The several‐nm‐space between the nanodiamonds is filled with a medium that reversibly deforms and recovers. Hence, nanodiamonds linked in the medium are arranged in several‐nm intervals. To prepare the nanodiamond glass, nanodiamonds are dispersed as inorganic nanoparticles with highly reactive functional groups into natural rubber as an incompressible medium exhibiting reversible deformation and recovery. Nanodiamond glass can be distinguished from nanodiamond‐filled rubber, which exhibits ordinary entropic elasticity. Natural rubber particles dispersed in water (i.e., latex) are used to prepare nanodiamond glass, chemically embed nanodiamonds onto the surface of the natural rubber particles, and subsequently attach the surfaces together to achieve close packing of the nanodiamonds. Increasing the modulus of natural rubber constrained in the nanospaces ensures the energetic elasticity of nanodiamond glass. This work demonstrates that nanodiamond glass with energetic elasticity is a new research field.     

A polydimethylsiloxane diaphragm integrated with a sputtered thin film NdFeB magnet

Microsystem Technologies - In this paper we propose a MEMS fabrication process that enables a polydimethylsiloxane (PDMS) diaphragm to be integrated with a sputtered thin film permanent magnet...     

CBED study of grain misorientations in AlGaN epilayers

Large angle convergent beam electron diffraction (LACBED) has been used to examine AlGaN epilayers grown by facet-controlled epitaxial lateral overgrowth on GaN/(0001) sapphire substrates in prototype UV laser structures. The substrates, defined by masks with seed openings along a <10-10> stripe direction, had GaN seed columns with {11-22} surfaces. Studies were carried out on cross-sectional samples cut perpendicular to the stripe axis. An LACBED analysis of the orientation of (000 2) planes, and of the (11-20) planes parallel to the stripe axis, revealed that the AlGaN wings were both rotated by angles of 1-2 x 10(-2)radians about the 10-10 stripe axis with respect to the underlying GaN, and distorted due to misfit strains. It is shown that the results are consistent with the observed structure of the AlGaN/GaN and the wing/wing boundaries, and with a new model for the generation of a-type misfit dislocations at the AlGaN/GaN interface.