Том 61, № 4 (2018)

A method for evaluation of the performance of the disk subsystem of a data buffering and transmission system and results of experimental studies of the performance of the disk subsystem according to the developed method are presented. A conclusion is drawn on the reasonability of the use of hard-disk drives that provide the required read/write rates with a sufficiently high level of reliability in prospective development of the modern high-capacity NearLine SAS (NL-SAS).

The functional diagram and the automation system of a CVD-reactor for the synthesis of vertically oriented carbon nanotube arrays on silicon substrates are described. The system is intended predominantly for recording the physical parameters of the CVD-reactor in real time, generating the instructions for the operator on the selected synthesis-process flow, on-screen display of the selected parameters, and management of the automatic protection of the reactor units and assemblies against contingencies or unspecified actions of the operator. The structure of the system for data acquisition, visualization of synthesis variables, and the CVD process control that allows the synthesis of vertically oriented carbon nanotube arrays is presented.

An FPGA-based acoustic time-delay meter with the post-detection correlation processing of pseudo-noise signals is proposed. The measurement method is based on the real-time computation of the mutual correlation function between the reference signal that follows the modulation law and the received signal. The experimental results obtained using a prototype of the developed system are presented. The results validated the viability of the developed software and hardware solutions as applied to acoustic-, radio-, and hydroacoustic-location systems.

The results of investigations of silicon diodes in the mode of switching by nanosecond pulses, which initiate an impact-ionization wave, are presented. It is shown that the switching process is significantly influenced by dislocations that are formed in the surface layers of diode structures during their manufacture.

The stable operation of pulse sequence generators at high temperatures (200°C) has been an important issue for some time in the application of nuclear magnetic resonance (NMR) apparatus for oil exploration. The application of system-in-package (SiP) technology was used to improve the temperature-resist grade of the hardware platform. A pulse sequence generator that meets the requirements of accurate phase and adjustable frequency during NMR apparatus in high temperature environments was designed and implemented. At ambient temperatures of up to 200°C, experimental results show that the delay times of the rising and falling edges of the pulse are 3.2 and 3.35 ns. respectively. The eye diagram Q factor of the critical path is not less than 15, and the Bit Error Rate (BER) is not more than 10^–50. The experimental results show that a pulse sequence generator can meet the requirements of high temperature NMR apparatus, and can also provide a template for the design of an NMR pulse sequence generator for special fields of application, such as deep sea surveys and aviation.

Coherent summation was performed for the wave fields of pairs of X-band nanosecond Gunn oscillators based on 3A762 diodes. Each oscillator was excited by its own modulator. The initial phase of the microwave pulse of each oscillator was fixed by the leading edge of the electrical pulse from the respective modulator. The modulators were triggered by a common sync pulse. The total microwave-radiation patterns of antenna pairs connected to the Gunn oscillators were in good agreement with the total radiation patterns of these antennas excited in phase by a standard oscillator.

A method for increasing the sensitivity of mass-spectrometric measurements in the analysis of small amounts of gases, which are insufficient for organizing a stationary flow through an ion source, is considered. Measurements are carried out upon a single injection of a portion of a gas. The use of this method for increasing the sensitivity in isotope helium analyses on MI9303 magnetic-resonance mass spectrometers allowed the sensitivity of the spectrometer to be increased to ~10⁵ atoms in a sample, i.e., it allowed measurements for a helium volume in a sample of up to ~10⁻¹⁴ cm³. The experience of carrying out isotope analyses in samples of inert gases of various origins using different methods for evacuating chambers of mass analyzers was generalized.

A device for forming an ion beam in a plasma-optic mass separator was developed on the basis of a two-chamber plasma accelerator—thruster—with anodic layers (TAL). The anode of the second chamber in the TAL is replaced with an azimuthator of the mass separator. Functionally, the azimuthator plays the role of the cathode for both the first and second accelerator chambers. This becomes possible after a potential that is negative with respect to the TAL anode is applied to the azimuthator–cathode. The ion source has been tested as a part of the POMS-E-3 mass separator. The ion density at the output of the source is 2–4 times higher than the density at the output of the “classical” two-chamber TAL.

The problems of introducing automation into experimental studies required for the development of an atomic vapor laser isotope separation method are considered. The investigations are carried out at a facility consisting of a vacuum module and a set of wavelength-tunable dye lasers pumped with copper vapor lasers. The vacuum module contains an atomic beam source, a quadrupole mass spectrometer, and a luminescence detection system. The approaches used to stabilize the laser wavelength and to scan the laser wavelength with the simultaneous recording of the mass-spectrometer and luminescence signals in strong high-frequency electromagnetic fields accompanying the operation of copper vapor lasers are also considered. Examples of experimental results are presented.

The results of tests of a new fiber-optic probe–objective for measuring both IR diffuse-reflection spectra and other types of spectra of solids at various temperatures are presented. In comparison with the conventional devices, the new scheme for measuring diffuse-reflection spectra has such advantages as the minimum distortion of spectra by the specular and Fresnel diffuse components of the reflection from surface irregularities and the linearity of the concentration dependences. The use of a fiber-optic probe–objective provides the ability for the simultaneous analysis of the solid phase and outgoing gases with increasing temperature and calibration of the spectral methods using the thermogravimetric-analysis data. An example of monitoring the process of drying catalysts in laboratory studies when analyzing composite and other materials is used to consider the prospects for using the probe–objective.

The types of astronomical-spectrum calibrations in the wavelengths used in spectroscopy of stars at the 6-m BTA optical telescope are listed. A device has been developed for simultaneous recording of a star spectrum and a reference emission spectrum.

Experimental studies of the operating modes of a laser photo-acoustic SF₆ gas analyzer that were aimed at reducing its energy consumption were carried out. It was shown in the experiments that an average power of CO₂ laser radiation of at least 100 mW is required for the assured detection of low SF₆ concentrations (less than 100 ppb). To reduce the energy consumption of the gas analyzer, it is proposed to decrease the repetition frequency of CO₂ laser pulses by several times and operate on subharmonics of the resonance frequency of the photo-acoustic detector. The experimental results made it possible to reduce the energy consumption of the gas analyzer to ~15 V A and use a Li-ion battery from a laptop to power it. The duration of the continuous operation of the gas analyzer on one battery charge was at least 6 h.

Designs of piezoelectric pressure gauges based on PZT-19 ceramics and equipment for testing and calibration of piezoelectric gauges are described. Tests of the developed piezoelectric transducers in a shock tube showed that their characteristics are stable in time, the sensitivity ranges from 5 to 50 mV/bar, the operating pressure range is up to 100 bar, and the frequency range with a high-resistivity matching amplifier is 10–5 × 10⁵ Hz. The level of errors in measurements of pulse and oscillatory pressures is estimated as 5%.

Based on passive and wireless surface acoustic wave (SAW) sensing technology, a sensor terminal was designed to measure the contact stress in a cramped metallic slit with less than 0.5 mm in width. A layered structure of force-sensitive element with 0.5 mm in total thickness was put forward to package SAW resonator. Thin films with elasticity and flexibility were adopted to transfer load effectively between rigid surfaces. A flexible transmission line with double-stub structure and a patch microstrip antenna were used to realize the wireless interrogation to the sensor. The force-sensitive element model was built and simulated with FEA software (COMSOL Multiphysics). The sensor prototype exhibited significant linear and repeatable frequency shifts for the loads in the range of 0–4 MPa. The linearity error was ±3% of full-scale output (FSO), and the accuracy was ±1.25% FSO. The usage of elastic films in force-sensitive element caused hysteresis in output, but the hysteresis error was controlled in an acceptable range of ±3.8% FSO.

A new experimental setup for studying various phenomena in both cryogenic helium plasma and dusty plasma structures in a low-pressure gas discharge within the temperature range of 1.6–300 K is described. The setup is equipped with a modern data-acquisition system and high-speed video cameras to observe processes in dusty plasma structures. For the first time, dusty plasma structures were observed and studied at temperatures below 4 К.