A fluid of spheroids, ellipsoids of revolution, is among the simplest models of the disordered matter, where positional and rotational degrees of freedom of the constituent particles are coupled. However, while highly anisometric rods, and hard spheres, were intensively studied in the last decades, the structure of a fluid of spheroids is still unknown. We reconstruct the structure of a simple fluid of spheroids, employing direct confocal imaging of colloids, in three dimensions. The ratio t between the polar axis and the equatorial diameter for both our prolate and oblate spheroids is not far from unity, which gives rise to a delicate interplay between rotations and translations. Strikingly, the measured positional interparticle correlations are significantly stronger than theoretically predicted, indicating that further theoretical attention is required, to fully understand the coupling between translations and rotations in these fundamental fluids.

We employ real-time three-dimensional confocal microscopy to follow the Brownian motion of a fixed helically shaped Leptospira interrogans (LI) bacterium. We extract from our measurements the translational and the rotational diffusion coefficients of this bacterium. A simple theoretical model is suggested, perfectly reproducing the experimental diffusion coefficients, with no tunable parameters. An older theoretical model, where edge effects are neglected, dramatically underestimates the observed rates of translation. Interestingly, the coiling of LI increases its rotational diffusion coefficient by a factor of 5, compared to a (hypothetical) rectified bacterium of the same contour length. Moreover, the translational diffusion coefficients would have decreased by a factor of ~1.5, if LI were rectified. This suggests that the spiral shape of the spirochaete bacteria, in addition to being employed for their active twisting motion, may also increase the ability of these bacteria to explore the surrounding fluid by passive Brownian diffusion.

We describe the preparation of high-temperature PbTe diodes. Satisfactory rectification was observed up to 180-200 K. Two types of diodes, based on a p-PbTe single crystal, were prepared: (1) by In ion-implantation, and (2) by thermodiffusion of In. Measurements were carried-out from ~ 10 K to ~ 200 K. The ion-implanted diodes exhibit a satisfactorily low saturation current up to a reverse bias of ~ 400 mV, and the thermally diffused junctions up to ~ 1 V. The junctions are linearly graded. The current-voltage characteristics have been fitted using the Shockley model. Photosensor parameters: zero-bias-resistance x area product, the R0C time constant and the detectivity D* are presented

We describe here the characteristics of two types of high-quality PbTe p-njunctions, prepared in this work: (1) by thermal diffusion of In 4 Te 3 gas (TDJ), and (2) by ion implantation (implanted junction, IJ) of In (In-IJ) and Zn (Zn-IJ).The results, as presented here, demonstrate the high quality of these PbTe diodes.Capacitance-voltage (C-V) and current-voltage (I-V) characteristics have been measured.The measurements were carried out over a temperature range from ~ 10 K to ~ 180 K.The latter was the highest temperature, where the diode still demonstrated rectifying properties. This maximum operating temperature is higher than any of the earlier reported results.The saturation current density, J 0 , in both diode types, was ~ 10 -5 A/cm 2 at 80 K, while at 180 K J 0 ∼ 10 -1 A/cm 2 in TDJ and ~ 1 A/cm 2 in both ion-implanted junctions. At 80 K the reverse current started to increase markedly at a bias of ~ 400 mV for TDJ, and at ∼ 550 mV for IJ. The ideality factor n was about 1.5 -2 for both diode types at 80 K. 2The analysis of the C-V plots shows that the junctions in both diode types are linearly graded. The analysis of the C-V plots allows also determining the height of the junction barrier, the concentrations and the concentration gradient of the impurities, and the temperature dependence of the static dielectric constant.The zero-bias-resistance×area products (R 0 A e ) at 80 K are: 850 Ω⋅cm 2 for TDJ,

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