Laser emitter of ultrashort pulses with controllable duration for robotics

This paper presents the analysis and experimental research of an original scheme of the solid-state laser resonator, capable of emitting subnanosecond radiation pulses with controllable duration. For this purpose, it is proposed to use the controllable Michelson interferometer, containing an electro optical phase modulator as a composed output resonator mirror. In this case, the interferometer provides the active resonator mode locking as well as the fast resonator Q-switching mode for effective generation of the output radiation pulses with variable duration.

NEODYMIUM LASER IN LARINGOTRACHEOSTENOSIS TREATMENT AFTER TRACHEOSTOMY IN CHILDREN

Objective. To evaluate the effect of neodymium laser application for successful decannulation in infants with a congenital and acquired tracheal stenosis and tracheostomy. Methods. 6 children were being treated in the 1^st City Clinical Hospital of Minsk in 2011-2014. All children underwent tracheostomy with a prolonged tracheal intubation and subsequent development of tracheostenosis. The children were examined using X-ray, esophagogastroscopy (PentaxEG-16K10), and bronchoscopy (Olympus MAF TYPE GM). Tracheal stenosis was treated using a medical multifunctional laser complex Multiline (“Linline Medical systems” Ltd, Belarus) equipped with a high-energy neodymium laser emitter. Children with excessive growth of granulations in thelumenof thetrachea underwent vaporization of granulations by means of a bulbous probe with a neodymium laser emitter (wavelength of 1340 nm, power: 15 W, 2 sec. exposure). In cicatricial tracheal stenosis, incisions were made with a laser scalpel (the wavelength of 1064 nm, power of 20 W). Results. Effective decannulation was observed in 5 children, including 4 children who underwent3-5 treatment sessions. In 1 child with the congenital subglottic larynx stenosis, to perform the decannulation became possible after 2 years and 24 sessions of laser recanalizationofstenosis and ablation of granulations. One child, after 9 treatment sessions, dropped out of observation, the result has not been defined. Conclusion. Tracheostomy in children promotes the formation of granulations in the tracheal lumen with the formation of stenosis, which subsequently hinders a successful decannulation. The neodymium laser application with the endoscopic access provides the visual direct approach to the focus of impact with the aim of laser-induced vaporization of soft tissues and recanalization of the trachealmass in children with short tracheal stenosis leads to successful decannulation. What this paper adds Firstly the neodymium laser for the treatment of congenital and acquired tracheal stenosis in children after tracheotomy has been used. The method has been developed for restoring the tracheal lumen by laser-inducedvaporization of excessive tracheal granulation and making scalpel incisions in the scar area. It is shown the neodymium laser application with the endoscopic access provides the visual direct approach to the focus of impact. Laser-induced vaporization of soft tissues and recanalization of the tracheal lumen in children with short tracheal stenosis leads to successful decannulation.

Анализ пороговых условий и эффективности генерации замкнутых мод в больших прямоугольных резонаторах на основе лазерных гетероструктур AlGaAs/GaAs/InGaAs

Threshold conditions and efficiency analsis of a semiconductor laser emitter with a large (1x1mm) rectangular resonator based on AlGaAs/GaAs/ InGaAs heterostructures for high-power strip lasers operating on high-Q internally circulating structures is presented. Two designs of emitters with different laser radiation propagation region characteristics are proposed, and the possibility of differential efficiency characteristic as high as high-power broad lasers (70% and more) is demonstrated.

Shooting Simulator «Inhibitor»: Mathematical Support for Ballistics of 7.62 Caliber Weapons

The software for support of external ballistics calculation for weapons of 7.62 mm caliber is described taking into account external factors for the optical-electronic tactical exercise machine for small arms "Inhibitor" developed at the Institute of Mechanics UdmFRC UB RAS and at Computer facilities department of Kalashnikov ISTU jointly with JSC «Kalashnikov» Concern». A tactical and technical task is given for ballistic calculation of the trajectory up to 2 km of range of weapon simulators with a laser emitter of the targeting point taking into account external factors: types of sights, especially optical, ballistic scattering of bullets, deflection of the bullet from the side wind and derivation, which have a significant impact on the ballistic trajectory. The implemented differential mathematical model of external ballistics relying on the aiming angle of the weapon simulator depending on the sight readings, the initial speed and ballistic coefficient of various types of ammunition in real time builds a ballistic trajectory with adjustments for the air temperature and pressure and dependence on lateral wind and random dispersion of bullets to further solve the "problem of meeting" with obstacles. The given results of software tests for the error in calculating the coordinates of the ballistic trajectory showed full compliance with the requirements and adequacy of mathematical models. It was concluded that further research and development of electronic shooting simulators were promising thanks to the improvement of computing tools and the development of software libraries in order to increase the accuracy of simulating external ballistics of simulators taking into account many external factors, expand functional networks and reduce cost and, therefore, increase competitiveness.

Shooting Simulator «Inhibitor»: Mathematical Support for Subsonic Weapon Ballistics

The mathematical support for calculation of external ballistics for subsonic weapons is described taking into account external factors for the tactical optical-electronic simulator for small arms "Inhibitor" developed at the Institute of mechanics UdmFRC UB RAS and at Computer facilities department of Kalashnikov ISTU jointly with JSC «Kalashnikov» Concern». The tactical and technical assignment is given for ballistic calculation of the trajectory and point of hit of subsonic simulators of PM weapon and GP-25 with the laser emitter of the targeting point taking into account external factors: position of the sighting bar of all types of sights (mechanical, optical, night) with the procedure of their preliminary sighting (transformation of coordinates of the laser spot into coordinates of the visual targeting point), features of the mounted trajectories of the GP-25 (air pressure drop with the height of the trajectory), air temperature and pressure, wind force, ballistic scattering minus the hardware error of the sighting point recorder (geometric subtraction of independent random errors). Mathematical models of external ballistics implemented in the software relying on the aiming angle of the weapon simulator, the initial speed and ballistic coefficient of various types of ammunition in real time in the simulator coordinate system make up a ballistic trajectory in order to solve the “meeting problem”. Results of software tests for the error in the calculation of ballistic trajectory characteristics are given. It was concluded that further research and development of electronic shooting simulators were promising thanks to the improvement of computing tools and the development of software libraries in order to increase the accuracy of simulating external ballistics of simulators taking into account many external factors, expand functional networks and reduce cost and, therefore, increase competitiveness.

Study of methods for measuring distances in scanning range

Recently, the market for scanning rangefinders, in other words, LIDARS, has begun to develop rapidly due to the new course for unmanned vehicles and the need for high-precision positioning of objects in construction, geodesy, military Affairs, navigation, etc. The leading manufacturers of such scanning devices are currently Velodyne, Ouster and Luminar. Each company has its own unique approach to creating LIDAR, which has both pros and cons. LIDAR itself is a scanning device designed to receive and process information about remote objects using active optical systems that use the phenomena of light absorption and scattering in optically transparent media. In other words, a LIDAR is a device that uses a laser emitter to detect an object, after which the beam from the object is reflected and hits the photodetector, which, in turn, generates a signal and transmits it to the time interval meter. The output is a two-or three-dimensional image of the scanned object in the form of dots, depending on the type of LIDAR. The more of them, the clearer the picture we have, their number directly depends on the number of lasers and the processing speed of the system. This work is devoted to a comparative analysis of methods for constructing LIDAR systems. The analysis is carried out in order to identify the most accurate method of measuring the distance to an object under various conditions, and a new self-oscillating principle of distance measurement is proposed, which allows you to bring the measurement accuracy to a new level.

Prediction of the color variation of moso bamboo during CO2 laser thermal modification

Thermal modification is widely used for bamboo materials as an efficient modification method. CO2 laser with the advantages of high energy density, short process period, non-pollution, etc. could be applied as a novel thermal treatment for wooden and bamboo materials processing. The laser intensity argumentation of power, motion arguments of feed rate, and sweep width for laser emitter were selected as input arguments for treating the Moso bamboo surface. The lightness variation and total color variation (∆L* and ∆E*) were collected using a portable colorimeter to describe the bamboo surface color variation after laser irradiation. Response surface methodology was chosen for designing experiments and modeling. The results showed that the increase of laser power had a positive influence on increasing the absolute values of ∆L* and ∆E*, but the feed rate of laser emitter and sweep width increasing had opposite effects on absolute values of ∆L* and ∆E*. The quadratic models of ∆L* and ∆E* created by response surface methodology were competent for describing the relationship between laser processing arguments and color indexes of ∆L* and ∆E*. This approach will be useful for selecting suitable and desirable processing arguments to get the surface color of bamboo productions.