SCIENCE & EDUCATION

pp. 534-549

pp. 409-426

pp. 427-443

pp. 444-457

pp. 458-481

pp. 482-496

pp. 209-229

pp. 230-243

pp.132-147

pp.148-161

pp.177-192

The paper demonstrates the characteristic features of images registered at quite low fluxes of optical radiation, in which each element (pixel) of the photosensitive matrix has one photon in average. It also considers noise characteristics of the image detector of the newest type i.e. CCD with internal electronic multiplication (Electron Multiplying CCD, EMCCD). It is shown that the internal electron multiplication can significantly improve the signal-to- noise ratio of CCD detector and approach to the theoretical limit of sensitivity, limited by photon noise.Based on the EMCCD sensor TV device has been designed and created. It enables a record of images at ultra-low light levels of the order of 10e-4 lx.

Generator type magnetoelastic transducers are considered as fuze contact target sensors and as means of dynamic force measuring. It is shown that the transducer may have a nontraditional scheme containing only one output coil which is capable of integrating the input force signal. The generating effect in magnetically soft materials is characterized by “piezomagnetodynamic” hysteresis curves as a result of shock loading of the magnetic conductor. The results of experimental evaluation of the dynamic force function of contact target sensor are presented. The magnetoelastic transducer may also be used for the evaluation of bullet-proof vest efficiency.

The paper presents estimation of a sounding range of the airborne lidar in ultraviolet, visible, and near infrared spectral bands to solve a problem of wind shear detection for different altitude levels in the troposphere. It is shown that with the flying altitude rise there is a decrease of the sounding range, most of all, within the altitude of 5-10 km. This dependence is explained by the fact that in this range of altitudes there is a substantial decrease of aerosol scattering and extinction coefficients in the earth atmosphere with the increase of altitude. In  the lowest atmospheric layer the sounding range reaches maximum for  the wavelengths of 0.532 µm. With increase of flying altitude a difference between the sounding ranges for the wavelengths of 0.355, 9.532, and 1.54 µm decreases.

Application of adhesives and sealants in assembly technology of modern vacuum electro-mechanical devices allows connecting parts of different materials and significantly reduces the cost of products. However, outgassing of the adhesive joints deteriorates the vacuum inside the devices and limits their service life. Prolonged vacuum outgassing adhesive joints at elevated temperatures solves this problem but labor intensity of this operation prevents its use in mass production. For devices which are switched on relatively rare or once the desired vacuum level can be achieved by switching the getter directly before use. A short-time heating of the getter removes the main residual gas component - the hydrocarbons from the inner atmosphere of a vacuum device and provide the its functionality for a long time interval. An additional internal outgassing adhesive joints in the process of manufacturing the device is not required.

The article presents a developed laser rangefinder-speedometer (LRS) to replace the hand-held laser rangefinders on board transport spacecraft. Using the generalized function of efficiency, the LRFSM characteristics were estimated to show that the LRS has the highest efficiency as compared with existing analogues. As a result of relationship analysis of measuring speed accuracy and reliability of LRS laser source, Pareto sets are obtained, which enable providing the optimal operation conditions of a device. Energy calculations are performed for 5 km range measurements on space complex with a complicated configuration such as the International Space Station. The article considers the use of a geometric factor to protect a photo-detector from the overload when receiving a signal from the nearby angular reflector. The paper presents the results of efficiency evaluation using a generalized function for different types of laser sources that can be used in the LRS.

Existing shock sensors for car protection using the sensitive elements (SE) of piezoelectric, microphone and electromagnetic types and the analogue circuits of signal processing, have a number of essential shortcomings, such as "false" operations, instable temperature characteristics, nonlinear adjusting characteristic, and inconvenient control via variable resistors. The article considers issues to design the two-zone digital shock sensors with a SE of electromagnetic type. It offers a SE design, a circuitry solution, and algorithms of signal processing, which allow a remote control of prevention and alarm zones (with 16 gradations of sensitivity) and an algorithm for self-adapting to repeating external impacts. The method has been developed to form the basic levels of digital comparators for each gradation of sensitivity. Using this method enables the sensor to have the straight-line adjusting characteristic. Prospects for using the 3-axial micromechanical accelerometers as a SE of the shock sensors are proved.

The paper concerns a laser fluorescence method for vegetation monitoring. It presents the experimental study results of laser-induced fluorescence spectra of plants in stress situations caused by improper watering. It is shown that at 532 nm wavelength of fluorescence excitation a stress factor impact may cause both a magnification of fluorescent signal and a deformation of fluorescence spectrum profile.  An identifying factor to characterize deformation of laser-induced fluorescence spectrum profile can be a relationship of fluorescence intensities at two wavelengths, i.e. 685 and 740 nm. Measurement of fluorescent signal intensity and fluorescence spectrum profile can be a basis of the laser fluorescence method to detect the plant stress situations.

The mechanical heart support/replacement system - ventricular assist device (VAD) design task is considered in this article. Relevance of research in this area is due to high percentage of people suffering from heart diseases. The cause of every 5th death in the world is heart failure. Currently, a number of VAD models have been created some of which are successfully used in medical practice. Over years of research in this area the general concept of VAD development has been formed: requirements to systems have been established, approaches to the tasks solution have been developed, certain results have been received and existing lacks of VAD systems have been revealed. Rapidly developing technologies give more and more opportunities for solving the existing problems. This work presents an analysis of the problem of VAD systems development today. Biomedical and technical requirements to VAD systems are systematized, classification of the problems arising in the design process is carried out, finally, trends and new developments in this area are discussed.

One of the most important and challenging tasks of constructing the effective recognition systems is to select a working dictionary containing the most informative features. The successful solution of this problem provides both a reduced dimensionality of the feature vector and an improved efficiency of the recognition system as a whole. The article concerns the problem of reducing the feature space in pattern recognition algorithms using the object contours and proposes a method for its solution based on the search of the most essential features. It follows from the experimental results that the proposed method enables to abridge substantially the dimension of features dictionary and improve the efficiency of pattern recognition algorithm using the object contours on the basis of Fourier-descriptors.