Broadband measurements of acoustic attenuation in water-saturated sands

A method for the measurement of acoustic attenuation in water-saturated granular media as a continuous function of frequency is described. Results for a range of water-saturated sands are presented together with acoustic velocity data and discussed in relation with porosity and grain size variations.     

A simplified,miniature TEA-CO2 laser using a semiconductive pre-ionization technique

Using a pre-ionization system based on a silicon carbide compound and a pulse-forming network using a vacuum relay, we have been able to significantly reduce TEA0-CO₂ laser complexity while maintaining high output energy densities. The design and construction are detailed along with the experimentally obtained laser characteristics.     

High density polyethylene/hydrogenated oligo(cyclopentadiene) blends: Phase structure,thermal and mechanical properties

The article discusses the influence of an oligomeric resin, hydrogenated oligo (cyclopentadiene) (HOCP), on the morphology and properties of its blends with high density polyethylene (HDPE). HDPE/HOCP blends after solidification contain three phases: the crystalline phase of HDPE and two amorphous phases, one rich in amorphous HDPE and the other in HOCP. DSC thermograms and the loss modulus behaviors show that the γ transition is influenced by HOCP molecules and, in addition to the α_c transition of HDPE, there is another transition that is attributed to the HOCP-rich phase. The hypothesis of the two amorphous phases is confirmed by the optical microscopy observations performed on isothermally crystallized blend films. © 1994 John Wiley & Sons, Inc.     

DC current singularities in long Josephson tunnel junctions: Approximate solutions of the sine-Gordon equation with loss and bias

We construct approximate analytic solutions of the sine-Gordon equation with loss and bias, which describe the fluxon propagation in long overlap Josephson junctions. By these solutions a qualitative explanation of the main observed features of the DC current singularities can be easily obtained.