Investigation of discharge channel wall material influence on lifetime of hall effect thruster with high specific impulse

Results of 500-hour life tests of the 900-watt Hall-thruster laboratory model with the specific impulse of 2000 s are presented. The thruster discharge channel walls were manufactured from 60% BN + 40% SiO2 and >90% BN hot-pressed ceramics. The predicted total lifetime was ∼3000 h for both wall materials in spite of greater erosion resistance of pure BN in comparison with BN-SiO2 mixture. To clarify the accompanying phenomena, the following diagnostics were carried out. The surface microstructure and composition insulators were investigated by means of electron microscopy and X-ray fluorescence analysis and nearwall plasma parameters were measured with flat Langmuir probes. The obtained distributions of plasma parameters were compared with the results of stationary one-dimensional (1D) hydrodynamic modeling of discharge channel

20.9 Efficient bifacial isotype solar cell

The optimization ways and related photovoltaic parameters of the mono and bi facial solar cells based on n ITO SiO2 nSi isotype structures are presented. A technique for texturing the surface of silicon wafers oriented in 100 plane to form a regular pattern of inverted pyramids as well as irregular topography patterns was developed. The efficiency of the solar cells with monofacial sensitivity from silicon wafers with the surface patterned in the form of inverted pyramids was increased from 10.1 to 15.8 , which is by more than 5 higher compared to the efficiency of the solar cells with unstructured silicon surface. For solar cells with bifacial sensitivity, the total efficiency was increased from 12.6 to 15.7 for the case of irregular patterned silicon surface and up to 20.9 in the case of the regular patterned silicon surface. The developed and applied technique for the structurization of the surface of silicon wafers for solar cell devices resulted in an efficiency increase to up to 15.8 for monofacial and up to 20.9 for bifacial solar cells. Keywords ITO, Interface, Bifacial, Silicon Solar Cell, Optical Losses, Spray Pyrolysis, Texturizatio

Structural Lability of <i>Barley Stripe Mosaic Virus</i> Virions

<div><p>Virions of <i>Barley stripe mosaic virus</i> (BSMV) were neglected for more than thirty years after their basic properties were determined. In this paper, the physicochemical characteristics of BSMV virions and virion-derived viral capsid protein (CP) were analyzed, namely, the absorption and intrinsic fluorescence spectra, circular dichroism spectra, differential scanning calorimetry curves, and size distributions by dynamic laser light scattering. The structural properties of BSMV virions proved to be intermediate between those of <i>Tobacco mosaic virus</i> (TMV), a well-characterized virus with rigid rod-shaped virions, and flexuous filamentous plant viruses. The BSMV virions were found to be considerably more labile than expected from their rod-like morphology and a distant sequence relation of the BSMV and TMV CPs. The circular dichroism spectra of BSMV CP subunits incorporated into the virions, but not subunits of free CP, demonstrated a significant proportion of beta-structure elements, which were proposed to be localized mostly in the protein regions exposed on the virion outer surface. These beta-structure elements likely formed during virion assembly can comprise the N- and C-terminal protein regions unstructured in the non-virion CP and can mediate inter-subunit interactions. Based on computer-assisted structure modeling, a model for BSMV CP subunit structural fold compliant with the available experimental data was proposed.</p></div

Structural component composition of CP BSMV aggregation forms from far-UV CD spectra (as predicted by Dichroprot).

<p>Structural component composition of CP BSMV aggregation forms from far-UV CD spectra (as predicted by Dichroprot).</p