Proton-irradiation-immune electronics implemented with two-dimensional charge-density-wave devices.

We demonstrate that charge-density-wave devices with quasi-two-dimensional 1T-TaS2 channels show remarkable immunity to bombardment with 1.8 MeV protons to a fluence of at least 1014 H+cm-2. The current-voltage characteristics of these devices do not change as a result of proton irradiation, in striking contrast to most conventional semiconductor devices or other two-dimensional devices. Only negligible changes are found in the low-frequency noise spectra. The radiation immunity of these "all-metallic" charge-density-wave devices is attributed to the quasi-2D nature of the electron transport in the nanoscale-thickness channel, high concentration of charge carriers in the utilized charge-density-wave phases, and two-dimensional device design. Such devices, capable of operating over a wide temperature range, can constitute a crucial segment of future electronics for space, particle accelerator and other radiation environments.

[Preventive abdominal wall repair in high-risk groups of postoperative ventral hernia]. / Preventivnoe éndoprotezirovanie briushnoi stenki v gruppakh riska razvitiia posleoperatsionnykh ventral'nykh gryzh.

AIM: To identify the most important predictors of postoperative hernia and to determine the indications for preventive surgical repair of abdominal wall. MATERIAL AND METHODS: Prospective analysis included 398 medical records of patients who underwent median laparotomy. Experimental tensiometry was applied to determine strength of intact fascia. RESULTS: The main predictors of postoperative hernia are age over 60 years, obesity, upper median laparotomy, connective tissue insufficiency. Combination of factors increases the risk of hernia. The most 'intense' foci of aponeurosis is middle portion of epigastric and initial part of mesogastric areas. You need to consider this features during laparotomy closure. CONCLUSION: Preventive repair may be an effective method for prophylaxis of postoperative hernia after median laparotomy.

Quantum hydrodynamic equations and quantum-hierarchy decoupling scheme.

There is a need to extract the relevant device physics from exact quantum transport formulations, and hence to reduce the complexity of quantum transport simulations for practical applications. We use a Hermite polynomial expansion to drastically reduce the number of degrees of freedom associated with the momentum variables. The result is a quantum hierarchy in real space. We also give a general procedure for the quantum-hierarchy decoupling scheme to derive the quantum hydrodynamic (QHD) and quantum drift-diffusion transport equations. We present some numerical results for the quantum hierarchy. A rigorous foundation of a decoupling procedure is given whereby the lower-order equations are renormalized in terms of a self-consistent effective potential, quantum diffusion coefficient, and moments, endowed with all the quantum corrections to order variant Planck's over h(2). Our decoupling scheme is based on the general expression of Tr H(n) to order variant Planck's over h(2), valid at all temperatures without the need for expansion in terms of the small parameter and high temperature assumption. This is very important conceptually since existing QHD formulations, using expansion to order h(2), are based on a Boltzmann distribution with the restrictive assumption of a small parameter, which is not valid in abrupt heterojunction semiconductor devices. They also fail to account for important quantum nonlinearity in the form of nonequilibrium quantum corrections. These nonequilibrium quantum corrections are expected to play a major role in approximating the coherence manifested by the highly nonlinear current-voltage characteristics of resonant tunneling structures.