An experimental setup for precision processing of composite materials based on nanosecond pulsed and continuous ytterbium fiber lasers with a wavelength of 1.06 μm and a radiation power up to 1 kW with an optical scanning systems based on galvanic drives with a beam velocity of up to 17 m/s has been developed. The setup provides a power density in a focused light spot with a diameter of ≃100 μm using a continuous laser of 107 W/cm2 and a pulsed laser of 109 W/cm2, which is one order of magnitude higher than the threshold values necessary for removing carbon fiber in the evaporation mode. The focus depth of the focused radiation allows for high-quality processing of sheet blanks.
The paper describes a developed sample of a mobile (helicopter) laser spectroscopic system, provides diagrams, and presents discussion of the results of experimental studies of fluorescence and Raman spectra of model objects, simulating the presence of heavy hydrocarbons in various concentrations.
A set of output characteristics of copper vapor lasers with an average power level of 30-100 watts is considered. The radiation parameters of active media have been optimized for power consumption, buffer gas pressure of neon and hydrogen, repetition rate, and pump pulse parameters. A thyratron version of the switch was used as a pump generator; its high-voltage modulator has been made according to the capacity voltage doubling scheme with magnetic compression of the current pulses. We shall also discuss the issues of modifying the design of laser tubes (diameter is 4.5 cm, active length is 1520 cm) and the relationship with their lifetime. The issues of modern applications of high-power laser systems based on copper vapor are considered.
Experiments were carried out on model objects to study the fluorescence and Raman spectra, simulating the presence of heavy hydrocarbons in various concentrations. The use of several sensing wavelengths and a wide spectrum of recording wavelengths potentially makes it possible to identify the yield of such hydrocarbons, which create a concentration of saturated vapors of 0.02-10 ppm at a temperature of 20± 5 °С.
The results of comparative studies of laser cutting of glass are represented, which show that at high laser radiation powers it is possible to achieve the glass cutting speeds of 0.5 m/s or more. Such high speeds of laser cutting of glass with a thickness of more than 3 mm open up the possibility of using the modern powerful lasers in the glass industry.
The development of the electronic industry, with the further miniaturization of electronic components and the use of new materials puts forward increasingly stringent requirements for the quality, reliability and competitiveness of products. All this, in turn, dictates the creation of new technologies and technological processes. The microprocessing laser technologies at R&D production facility "Istok" named after Shokin " for the period 2003-2018, a series of modern automated laser technological installations of the "Caravel" type was created on the basis of industrial lasers and laser systems based on copper vapors and precision three-coordinate tables. This equipment with the diameter of the processing light spot of 10–20 μm and the peak power density of 109-1011 W/cm2 allows for efficient and high quality processing of foil (0.01-0.2 mm) and thin-sheet (0.2-1 mm) metal and the large range of non-metallic materials of microwave products.
The mechanism of mechanical ablation of nanoparticles during the interaction with a high-power laser radiation pulse is proposed. A particle is polarized under a laser electric field, and electric forces acting on field-induced oppositesign charges cause rupture stresses. Upon reaching the stresses exceeding the maximum allowable values for a given material, a nanoparticle decays into two ones. This effect can be used for narrowing the size distribution of nanoparticles produced by the laser ablation method.
We present new results on numerical investigation of characteristics of pulse-periodic inductive copper vapour lasers. In these lasers pump pulses are trains of high-frequency (~ 30 MHz) current oscillations repeated at a frequency of 2-17 kHz. An inductive laser with an annular working volume of 1.7 l was considered and its possible output parameters were studied. We analyze specific features of working medium excitation in an HF-discharge; diversity of the obtained laser pulse shapes and possible applications are discussed as well.
In the present paper we present the results of a comparative analysis of pulsed copper vapour lasers with visible emission wavelengths of 510.6 and 578.2 nm and pulse duration of 10-30 ns and known types of technological lasers as well as the prospects for using the copper vapor laser for microprocessing of materials.
The possibility of the Gadolinium nuclei energy levels population inversion under neutron bombardment is theoretically shown. In the process two isotopes of gadolinium take part. Light isotope Gd155 capturing neutron transforms to heavy isotope Gd156 at that heavy nucleus is in an excited metastable state. The population inversion is investigating during several tens of second when the neutron flux intensity is 1013 cm-2 · s-1.
Research on CVL installations with an average power of 20–25 W of cutting and drilling has shown wide range of applications of these lasers for micromachining of metals and a wide range of non-metallic materials up to 1–2 mm. From the analysis indicated that peak power density in the focused light spot of 10–30 μm diameter must be 109 –1012 W/cm2 the productivity and quality micromachining, when the treatment material is preferably in the evaporative mode micro explosions, followed by the expansion of the superheated vapor and the liquid. To achieve such levels of power density, a minimum heat affected zone (5– 10 μm) and a minimum surface roughness of the cut (1–2 μm), the quality of the output beam of radiation should be as high. Ideally, to ensure the quality of the radiation, the structure of CVL output beam must be single-beam, diffraction divergence and have at duration pulses τi = 20–40 ns. The pulse energy should have low values of 0.1–1 mJ at pulse repetition rates of 10–20 kHz. Axis of the radiation beam instability of the pattern to be three orders of magnitude smaller than the diffraction limit of the divergence. The spot of the focused radiation beam must have a circular shape with clear boundary, and a Gaussian intensity distribution.
N. Labin, A. Chursin, V. Paramonov, V. Klimenko, G. Paramonova, I. Kolokolov, K. Vinogradov, L. Betina, N. Bulychev, Yu. Dyakov, R. Zakharyan, M. Kazaryan, K. Koshelev, O. Kosheleva, A. Grigoryants, I. Shiganov, V. Krasovskii, V. Sachkov, P. Plyaka, I. Feofanov, C. Chen
The paper revealed the using of industrial production equipment ALTI "Karavella-1", "Karavella-1M", "Karavella-2" and "Karavella-2M" precision components of IEP production [1–4]. The basis for the ALTI using in the IEP have become the positive results of research and development of technologies of foil (0.01–0.2 mm) and thin sheets (0.3–1 mm) materials micromachining by pulsed radiation CVL [5, 6]. To assess the micromachining quality and precision the measuring optical microscope (UHL VMM200), projection microscope (Mitutoyo PV5100) and Carl Zeiss microscope were used.
This work scales the present globalism of ecological and energetic problems. The ecological problem is connected with environment pollution by polymeric waste. The energetic problem - with traditional approaches of modern energetic, in particular, use of fossil fuel for energy production and concentration of capacities for ensuring overall performance of global power supply systems that doesn't guarantee a sustainable development of power for long prospect, doesn't provide power safety of the country. The second part of work is devoted to a choice of the most effective solutions of the present global problems. The authors have proposed the plasma-chemical method of the polymer waste processing and developed a schematic diagram of the reactor. The paper contains the results of the theoretical calculation of the polymer waste processing products. The reagents, allowing to obtain hydrogen and other liquid products from polymer waste are selected. It is proposed to use rare elements for increasing the efficiency of hydrogen production from polymer waste. The results of the calculation of the efficiency of hydrogen production from polymer waste using molybdenum are revealed in the paper.
The aim of study is to demonstrate that separation of solvated ions in solution of mix of salts under the action of external periodic electric field happens because of around ions there are formed clusters consisting of molecules of solvent and the sizes of such clusters have dimensions ~ 0.1 μm.
In investigations the sizes of clusters theoretically were defined and experimentally value of frequency of external electric field which action excites the effect of separation of the solvated ions was defined.
Experiments were done in the Technical Physics Chair of the National Research Tomsk Polytechnic University.
At theoretical determination of the dimensions of clusters Poisson's equation was solved and was considered that polar molecules of solvent are oriented under the action of electric field of an ion. The chemical composition of samples of solutions was determined by means of the spectrophotometry and he X-ray excited fluorescent radiation analysis method.
Theoretical estimates and results of experiments confirmed the assumption that clusters which are formed around ions in solutions have the dimensions ~ 0.1 μm.
Results of investigation testify that placing of volume distributed electric charge of ion in dielectric liquid is accompanied by formation of the supramolecular particles, which we called "clusters", linear sizes of which is significantly more than first and second radiuses of solvation (~ 1 Angstrom) and reach size ~ 0.1 μm. At such sizes inertial properties of clusters and their natural frequencies give the chance to operate their movement by means of action of external electric field on solution.
New materials with prescribed isotopic composition could open good possibilities of functional characteristics
needed for the progress in science and technology. [1]. It have been shown, that the thermal conductivity of the
monocrystallic 70Ge (99,99 %) at 15 K was as much as 8.1 higher than the corresponding parameter of the natural
isotopic structure [2]. Applications of the single isotopes compositions are restricted by their high cost. That's why
it is very promising to find out new and less expensive methods of isotope separation and characterization of new
materials [1].
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