Relationships between the J-integral and the crack opening displacement for stationary and extending cracks

Relationships between the J-integral and the crack opening displacement δ_t are obtained by exploiting the dominance of the Hutchinson-Rice-Rosengren singularity in the crack-tip region. The coefficient d_n that relates J to δ_t, is dependent on the material deformation properties and is independent of crack configuration under small-scale yielding conditions. For low hardening materials, d_n appears to be configuration dependent in the fully yielded state. Similarly, the slope of the J-resistance curve is relatable to an operationally defined crack opening angle if J-controlled crack growth conditions are met. These relationships are corroborated by finite element results for the complete regime of elastic-plastic deformation and experimental data for A533B steels, HY-80 steels and several other ductile metals.     

Author index for volume 81

Certain types of integral inequalities which were established by LaSalle, Gollwitzer, Langenhop, Bondge, and Pachpatte are reviewed and unified. The bounds provided by these inequalities can be used in the study of the theory of partial differential and integral equations.     

Kinetics of the Ruthenium-Catalyzed Hydrogenation of Acetic Acid to Ethanol

The ruthanium-catalyzed hydrogenation of acetic acid to ethanol was conducted at 140–230° under hydrogen pressure of 40.8–81.6 atm with a catalyst loading of 4 g/L. The best rate expression to fit the experimental results is Kinetic data at 230° were obtained with an average error of 7%. It is concluded that the rate limiting step is the first addition of hydrogen to acetic acid to produce aldehyde and water as the intermediates. The activation energy is 12.7 kcal/mole.     

Photo-induced complex permittivity measurements of tellurium at 9 GHz

A microwave transmission method to determine the photo-induced complex relative permittivity of semiconductors (photodielectric effect and photoconductive effect) has been investigated. Measurements have been made on single crystal tellurium samples at a temperature of 100 K, at a microwave frequency of 9 GHz in optical frequencies between about 0.7×10¹⁴ and 2.0×10¹⁴ Hz (i.e. wavelengths between 1.5 and 4.2 μm). From the measured data, the relaxation time of the free carriers in the tellurium samples was calculated.     

All-optical image processing with a supranonlinear dye-doped liquid-crystal film

We demonstrate a dynamic all-optical image-intensity-inversion technique that uses self- and mutual-phase-modulation effects with a highly nonlinear nematic liquid-crystal film placed in an intermediate focal plane. This process requires submilliwatt optical power, responds in a few milliseconds, and can be realized over a very broad spectral range.     

Quantum teleportation of a polarization state with a complete bell state measurement

We report a quantum teleportation experiment in which nonlinear interactions are used for the Bell state measurements. The experimental results demonstrate the working principle of irreversibly teleporting an unknown arbitrary polarization state from one system to another distant system by disassembling into and then later reconstructing from purely classical information and nonclassical EPR correlations. The distinct feature of this experiment is that all four Bell states can be distinguished in the Bell state measurement. Teleportation of a polarization state can thus occur with certainty in principle.     

Dynamic soliton-like modes

Incoherent optical spatial solitons require noninstantaneous nonlinearity, i.e., the local intensity fluctuation of the solitons must be faster than the medium can respond. Observing partially incoherent bicomponent solitons, we find that there exists a threshold speed. When the fluctuation of the soliton intensity, resulting from the time-varying interference of its constituent modes, is below the threshold, the soliton beam and its induced waveguide oscillate violently. Just above the threshold, the soliton-induced waveguide is observed to be dragged by the soliton beam.