Photoelectric Parameters of Photodetectors Based on Thin Microcrystalline Films of CH3NH3PbI3 Perovskite

Technical Physics Letters - Photoelectric characteristics of photodetectors of the type of a photoresistor based on microcrystalline films of the organometallic perovskite CH3NH3PbI3 with gold and...     

The ZEUS forward plug calorimeter with lead–scintillator plates and WLS fiber readout

A Forward Plug Calorimeter (FPC) for the ZEUS detector at HERA has been built as a shashlik lead–scintillator calorimeter with wave length shifter fiber readout. Before installation it was tested and calibrated using the X5 test beam facility of the SPS accelerator at CERN. Electron, muon and pion beams in the momentum range of 10–100 GeV/c were used. Results of these measurements are presented as well as a calibration monitoring system based on a ⁶⁰Co source.     

Populations of antibiotic-resistant coliform bacteria change rapidly in a wastewater effluent dominated stream

Incomplete elimination of bacteria and pharmaceutical drugs during wastewater treatment results in the entry of antibiotics and antibiotic-resistant bacteria into receiving streams with effluent inputs. In Mud Creek in Fayetteville, AR, ofloxacin, trimethoprim, and sulfamethoxazole have been detected in water and sediment, and tetracycline has been detected in sediment downstream of treated effluent input. These antibiotics have been measured repeatedly, but at low concentrations (< 1 μg/L) in the stream. To determine if effluent input results in detectable and stable changes in antibiotic resistances downstream of effluent input, antibiotic resistance in Escherichia coli and total coliform bacteria in Mud Creek stream water and sediment were determined using a culture-based method. Isolated E. coli colonies were characterized for multiple antibiotic resistance (MAR) patterns on solid media and to evaluate E. coli isolate richness by amplification of a partial uidA gene followed by denaturant gradient gel electrophoresis (DGGE). Despite temporal variability, proportions of antibiotic-resistant E. coli were generally high in effluent and 640 m downstream. The MAR pattern ampicillin-trimethoprim-sulfamethoxazole was associated with a DGGE profile that was detected in effluent and downstream E. coli isolates, but not upstream. Percent resistance among coliform bacteria to trimethoprim and sulfamethoxazole was higher 640 m downstream compared to upstream sediment and water (with one exception). Resistance to ofloxacin was too low to analyze statistically and tetracycline resistance was fairly constant across sites. Resistances changed from 640 m to 2000 m downstream, although dissolved nutrient concentrations within that stream stretch resembled effluent. Antibiotic resistant bacteria are entering the stream, but resistances change within a short distance of effluent inputs, more quickly than indicated based on chemical water properties. Results illustrate the difficulty in tracking the input and fate of antibiotic resistance and in relating the presence of low antibiotic concentrations to selection or persistence of antibiotic resistances.     

A stabilized pulsed repetition-rate CO<Subscript>2</Subscript> laser for a laser-plasma generator of multiply charged ions

The design of a laser oscillator with a stabilized frequency composition and a stabilized intensity of output radiation is described. The oscillator’s basic component is a TEA CO₂ module pumped by a self-maintained discharge and operating in a repetition-rate mode at a frequency of up to 3 Hz. A circuit for the formation of a self-maintained homogeneous discharge in the working volume of a CO₂ + N₂ + He mixture at atmospheric pressure is the basic component of the gas-discharge module. This circuit is based on the generation of a high-voltage pulse with a special profile, which provides high-reliability excitation of a discharge and pulse-to-pulse reproducibility of the discharge characteristics. The use of a hybrid circuit in the optical oscillator allows selection of a single longitudinal mode in the output radiation spectrum, thus eliminating undesirable interference phenomena, which lead to instability of the instantaneous values of the radiation intensity. During the development of the oscillator, the optimal operating parameters of the hybrid circuit were obtained, which ensure the high quality and reproducibility of the spatiotemporal and energy parameters of laser radiation.     

A nonlinear model of a microstrip transmission line with a ferromagnetic film in the presence of excited magnetostatic waves

A method is proposed for constructing a nonlinear mathematical model of a microstrip line with a ferromagnetic film in the presence of excited magnetostatic surface waves. The method uses multiobjective optimization and regression analysis of the data obtained from a multifactorial designed experiment. The adequacy and accuracy of calculations performed with the model constructed are confirmed by comparison with experimental results. Dependences of the radiation impedance of a line with particular parameters on the power of the input signal are calculated for different values of the external magnetic field and frequency.     

Electron Cooling and Control of Josephson Current at Sub-Kelvin Temperatures

The factors limiting cooling electrons by biased tunnel junctions have been considered. At low temperature range the deviation from equilibrium, superconductor overheating and states within the superconductor gap limit the achievable minimum temperature. Strong increase of electron–phonon coupling at higher temperature limits the temperature range of effective electron cooling to sub-Kelvin region. Control of Josephson coupling in superconductor-normal metal-superconductor weak link by electron cooling in normal electrode has been demonstrated experimentally.     

Water Absorption and Mechanical Properties of Silica Porous Glasses

We have estimated the mechanical properties of silica porous glasses (SPG) using special two-layered structures consisting of a SPG layer on a solid glass substrate. These structures turned curved after keeping them in moist atmosphere. The linear dimensions of dry free-standing SPG wafers with the same pore size distribution increased significantly (up to 1.5%) after water vapour soaking. Bending angles of two-layered structures and the values of linear expansions were used to estimate SPG elastic constants and the mechanical stresses arising in porous glasses as the result of water absorption.     

Development of lightweight respirators using activated carbon fabrics

Conclusions -- Activated carbon materials have been developed for respirators based on Ural or UVK materials for the protection of breathing organs from ammonia or sulfur dioxide, with a protective action life of 2 and 5–6 h, respectively.VNITIUS. Translated from Khimicheskie Volokna, No. 3, pp. 51–52, May–June, 1991.     

Plasma-Sprayed Lead Zirconate Titanate-Glass Composites

A plasma-spray process was used to produce piezoelectric lead zirconate titanate (PZT)-glass composite thick films. The films were found to have the same crystal structure as the PZT (Navy-type V) and lead-based glass starting powder mixture. The films showed good adhesion to stainless steel and silver-coated glass slides and poor adhesion to aluminum substrates. The dielectric constant of the films varied between 58 and 20 with dissipations between 0.019 and 0.032. The films were poled, and their piezoelectric charge coefficient, d ³³, was 1.1 pC/N.