Most static mixers are designed to maximize radial mixing to achieve compositional and thermal homogeneity. Flow inverters maximize heat transfer. Axial mixers that closely approximate an exponential distribution of residence times have been devised as well. More recent papers describe static mixers for surge dampening in industrial swing-cycle processes (Smith, Graham, and Palamara, 2006). An ...

ÐThe ps optical response of ultrathin NbN photodetectors has been studied by electro-optic sampling. The detectors were fabricated by patterning ultrathin (3.5 nm thick) NbN ®lms deposited on sapphire by reactive magnetron sputtering into either a 5 10 mm microbridge or 25 1 mm wide, 5 mm long strips connected in parallel. Both structures were placed at the center of a 4 mm long coplanar wavegu...

We have fabricated and tested submillimeter-wave superconductor–insulator–superconductor ~SIS! mixers using very high-current-density Nb/AlN/Nb tunnel junctions (Jc'30 kA cm ). The junctions have low-resistance-area products (RNA'5.6 V mm ), good subgap-to-normal resistance ratios Rsg /RN'10, and good run-to-run reproducibility. From Fourier transform spectrometer measurements, we infer that vR...

Waveguide SIS mixers are presented in which Nb/Al-AlOx/Nb tunnel junctions are integrated with both NbTiN/SiO2/NbTiN and NbTiN/SiO2/Al tuning circuits. The mixers with a NbTiN/SiO2/NbTiN tuning circuit yield relatively low receiver noise temperatures between 700 and 830 GHz, but their sensitivity drops significantly above ~ 850 GHz. In contrast, low-noise heterodyne mixing near 1 THz is observe...

In this paper we derive two rigorous properties of residence-time distributions for flows in pipes and mixers motivated by computational results of Khakhar et al. [Chem. Eng. Sci. 42, 2909 (1987)], using some concepts from ergodic theory. First, a curious similarity between the isoresidence-time plots and Poincare maps of the flow observed in Khakhar et al. is resolved. It is shown that in long...