bluuebunny/crossref_metadata_2025_split huggingface dataset:
Investigation of spectrally-dependent phonon relaxation mechanism in Yb:YAG gain media and its consequences for thin disk laser performance
Authors: Severová P , Nagisetty S S , Chyla M , Miura T , Endo A , Smrž M , Mocek T 
Published: January 2020

Abstract
Nonlinear phonon relaxation in Yb:YAG gain media has previously been investigated, and a hypothesis correlating photo-induced free electrons and heat generation in crystals pumped at a wavelength of 940 nm was established (Brandt et al 2011 Appl. Phys. B 102 765–8). Later, we demonstrated efficient suppression of nonlinear phonon relaxation by zero-phonon line (ZPL) pumping of Yb:YAG (969 nm). However, no hypothesis has yet been tested that correlates the heat load and the free electrons in Yb:YAG media. We investigate, both theoretically and experimentally, the behaviour of an Yb:YAG slab pumped by a high-power laser diode at a conventional broadband line (absorption maximum at 941 nm) and a ZPL (absorption maximum at 969 nm), and we compare the generated photocurrent, temperature, and absorbed pump power for those two pump wavelengths. Although the hypothesis established by Brandt et al (2011 Appl. Phys. B 102 765–8) was not confirmed, and the measured photocurrent was identical for the two pump wavelengths, our measurement contributes to the knowledge of the inner processes in Yb:YAG active media. In the following steps we characterized an Yb:YAG thin disk laser, measured the spectrally-resolved absorption and disk surface temperature, and optimised our predictive model of thin disk behaviour. All the experimental and theoretical results are reported.
Surface traps-related nonvolatile resistive switching memory effect in a single SnO2:Sm nanowire
Authors: Zhou Huiying , Shi Haiping , Cheng Baochang 
Published: January 2020

Abstract
For nanostructure SnO2, it is very difficult for its electric properties to accurately control due to the presence of abundant surface states. The introduction of Sm can improve the traps in surface space charge region of SnO2 nanowires, resulting in a controllable storage charge effect. For the single nanowire-based two-terminal device, two surface state-related back-to-back diodes are formed. At a relatively large voltage, electrons can be injected into the traps in surface space charge region from negative electrode, resulting in a decrease of surface barrier connected with negative electrode, and contrarily electrons can be extracted from the traps in surface space charge region into positive electrode, resulting in an increase of surface barrier connected with positive electrode. The reversible injection and extraction induce a nonvolatile resistive switching memory effect.
Nano-sphere surface arrays based on GaAs solar cells
Authors: Peng Yinsheng , Gong Shufeng , Liu Kai , Yao Minghai 
Published: January 2020

Abstract
In this paper, we present our efforts on simulating and analyzing the effect of two-dimensional nano-sphere surface array on the characteristic of GaAs solar cells. Based on the scattering and diffraction theory of the photonic crystals, the simulation results show that the distance of adjacent nano-spheres (D) has the pronounced influence on the conversion efficiency and exhibits much poor tolerance, the absolutely conversion efficiency is reduced by exceeding of 2% as the D varies from 0 to 1 μm, in addition, the lower conversion efficiency (< 18%) is exhibited and almost remains unaltered when theD is of > 2 μm. The radius (R) of nano-spheres demonstrates much great tolerance. For D = 0, the solar cells exhibit high conversion efficiency (> 20%) and the efficiency is only varied by less than 1% whenR is varied in a very wide region of 0.3–1.2 μm. One can also find out that there is good tolerance for efficiency around the optimal value of refractive index and there is only about 0.2% decrease in final cell efficiency for around ±24% variation in the optimal values, which implys that it does not demand high precision processing equipment and the whole nano-sphere array could be fully complemented using self-assembled chemical methods.
Evaluation of an integrated wood-burning stove with water tank system for heating rural homes in the Andean highlands of Peru
Authors: Soria L S G , Cabana-Hancco W R , Montoya L A , Palo-Tejada E 
Published: January 2020

Abstract
In this work, we study an improved wood-burning stove with a water tank placed in the flue gas outlet for use as a heater. This system takes advantage of the waste heat of the gases that pass through the chimney to heat the water contained in the tank. The evaluations were carried out in a house located in the district of San Antonio de Chuca (Imata), province of Caylloma, department of Arequipa, Peru, located above 4500m above sea level, where temperatures decrease to -20 °C during winter.
A method is proposed to measure the power input of the integrated tank, which consists of finding the maximum power that the flue gas delivers to the water in the tank when the stove is turned on. Once this power has been identified, the wood-burning stove is replaced by an electric heating system that delivers the same power to heat the water. Once the electrical system has been calibrated, the water in the tank is heated to different temperatures, and the following are calculated: the accumulated energy, the time needed to reach the desired temperature and the amount of wood that would be used if the kitchen were used for heating. The power that the heater can deliver to the test house is thus determined.
If the water in the tank is heated to 70 °C, this heating system can deliver an average power value of 450 W from 20:00 to 5:00 the next day.
Solar energy and the Energy Institute of the National University of Engineering (1962-1969)
Authors: Amaya E 
Published: January 2020

Abstract
This article examines one of the first institutional initiatives that promoted the study of solar energy in Peru. For this purpose, the case of the Energy Institute, a unit attached to the Faculty of Mechanical and Electrical Engineering (FIME) of the National University of Engineering, is analyzed during the 1960s. The Institute concentrated its efforts on the location of the regions with the highest solar incidence and in the development of devices that could use successfully this kind of energy. Through the hermeneutic analysis of journals, bulletins, theses, interviews and the use of specialized bibliography, we build a historical account in which the role of the Institute and its exponents for the promotion and research of solar energy is highlighted. With this objective, the article is divided into three sections, the first one details the context in which there was a greater awareness of the role that energy played in national development. Secondly, the changes that FIME went through and that allowed for the creation of the Energy Institute are described. Finally, the works undertaken by the Institute in the field of solar energy and the profile they take over time are exposed.
Mathematical model of the polymeric composition melt flow in the middle layer extruder of the coextrusion equipment
Authors: Dyadichev V V , Kolesnikov A V , Dyadichev A V , Menyuk S G , Melnik A Yu , Dyadicheva E A , Chornobay S Ye , Dyadicheva I V 
Published: January 2020

Abstract
The paper analyzes the urgency of using coextrusion technology while recycling the secondary polymeric raw material. The balance equation in the melt flow tensions is obtained. The connection between the tensor of tensions and tensor of deformation rates components is determined. The generalized power law is used as a rheological equation of state. The energy balance equation is worked out for the stable regime of the melt flow. The limiting conditions for the complete differential model of extrusion are determined. The equation for determining the effective output of the middle layer extruder is worked out based on the efficiency of the whole extrusion machinery which depends on the characteristics of the rest four extruders and the head’s characteristics.
Research of the effect of preliminary preparation on characteristics of powders for modification of nickel superalloys
Authors: Eremin E N , Filippov Yu O 
Published: January 2020

Abstract
To improve the mechanical and operational properties of nickel alloys, complex modification has become widespread, in which refractory compound powders are used as inoculants. However, industrial powders are distinguished by a significant scatter of the specific surface and particle dispersion values. The aim of the work was to study the effect of the preliminary preparation of powders on their dispersity and dimensional stability. A method is proposed for preparing ultradispersed powders of plasma chemical synthesis for introduction into a liquid metal, including high-temperature purification of particles using ultrasonic vibrations of 17·103 Hz with an input power of 20 W/cm3 in the melt of alkali metal halides. It is established that the preliminary preparation of powders provides activation of particles and increases their dispersion by five times, dimensional stability by seven times, and the number of particles of nano-sized level increases to eight times.
Corrosion properties of metal deposited by chromium flux-cored wire with boride-nitride-intrmetallic alloyng
Authors: Eremin E N , Losev A S , Borodikhin S A , Ponomarev I A 
Published: January 2020

Abstract
The corrosion properties of the metal deposited with chromium flux-cored wire with boride-nitride-intermetallic alloying are investigated. It was established that the metal deposited with wire PP-Kh15+0.5%BN+1.25%TiB2+0.5%ZrB2 at the initial stage of corrosion behavior, estimated by the time until the first signs of corrosion appear, exceeds the metal welded with standard wire Sv-20Kh13 in 3.6 times, and long-term corrosion resistance 2.22 times. In this case, only a slight degree of etching of the matrix is observed in such a deposited metal, there is practically no dissolution of the boundaries of the boride eutectic, and the hardening phases do not undergo any changes, which determines the lower corrosion rate of such a coating. The powder wire PPKh15+0.5% BN+1.25% TiB2+0.5% ZrB2 can be recommended for surfacing wear-resistant coatings on parts of petrochemical equipment operating in an aggressive environment under abrasive wear.
Long-range action effects in the formation of nanostructured topocomposites under the impact of combined ion-plasma flows
Authors: Korotaev D N , Poleschenko K N , Orlov P V , Vershinin G A , Tarasov E E , Ivanova E V 
Published: January 2020

Abstract
The article updates the long-range action effect in the formation of nanostructured topocomposites under the conditions of the ion-plasma impact. The authors study the features of the concentration dependences of the distribution of elements in the boundary layers in the formation of the two-layer system "film-base". They determine that under the conditions of the implementation of the cascade cross-effect at considerable depths in the material of the hard-alloy base, locally inhomogeneous areas are formed, resulting in an increase in the microhardness of the material. Within the framework of the worked out simulation model, the study of factors contributing to the manifestation of the long-range action effect is undertaken. The contribution to the change of concentration dependences of the temperature, different diffusion mechanisms and the pressure gradient is established and differentiated. Based on the synthesis and analysis of the dynamics of the competing processes of "deceleration - acceleration" of the diffusion, the explanation to the formation of the hardened sublayers in the hard-alloy base of topocomposites and their role in the manifestation of the long-range action effect is offered.
Calculation of Phase Trajectories for Microstructural Analysis in Liquidus Fields of Cristobalite and Tridymite for System FeO-SiO2-Fe2O3
Authors: Lutsyk V , Zelenaya A , Lamueva M 
Published: January 2020

Abstract
Two spatial models of the phase diagram (PD) of system FeO-SiO2-Fe2O3 have been developed based on the method of computer assembly from phase regions. The first variant presents the simplified phase diagram for system FeO-SiO2-Fe2O3 without taking into account the immiscibility surface and without separation of tridymite field on the liquidus of silicon dioxide. Such model includes five liquidus surfaces corresponding to the initial components and two binary compounds fayalite and magnetite. The second model is more accurate and takes into account the presence of a two-phase region of liquid immiscibility, which divides the cristobalite field into two parts. It includes eight liquidus surfaces: two parts of cristobalite, iron, hematite, tridymite, fayalite, wustite, magnetite. The liquidus field of Fe is hypothetical. The surfaces of solidus, solvus, ruled surfaces are constructed and the phase regions are formed. Based on the complete computer model, the possibility of microstructural composition analyzes for system FeO-SiO2-Fe2O3 in the crystallization fields of cristobalite and tridimite is demonstrated using the diagrams of vertical mass balance, calculated for a given mass center in all temperature range of crystallization. Two-, one-, and zero-dimensional concentration fields with coincided and individual sets of micro-constituents are shown.
Physico-chemical properties of V1-XFeX O2 and FeV2O6
Authors: Semenyuk N A , Kuznetsova Y V , Surikov Vad I , Surikov Val I , Prokudina N A , Yanchij S V 
Published: January 2020

Abstract
The article presents the results of a study of the heat capacity of V1-XFeXO2, temperatures of phase transformations in the semiconductor phase have been determined. The phase transition diagram of the V1-XFeXO2 system is presented. Values of the change in the entropy of phase transformations for V1-XFeXO2 materials are determined. It was determined that the values of the change in the entropy of the metal-semiconductor phase transition decrease with iron concentration increasing. The results of differential thermal analysis, temperature dependences of electrical resistivity, magnetic susceptibility, and thermoelectric coefficient are presented for the FeV2O6 compound. It was determined that the FeV2O6 compound is a semiconductor in the temperature range from 100 К up to 400 К.
Growth of conjugated semiconductor monocrystals based on benzothienobenzothiophenes from solutions
Authors: Shubenkova E G 
Published: January 2020

Abstract
Organic semiconductors are actively used for numerous applications, their use in flexible electronics technologies is especially promising. The mobility of current carriers is a determining parameter whose value is strongly influenced by the crystallinity and arrangement of molecules in the crystal lattice of the synthesized semiconductor materials. The goal of this work was to obtain thin monocrystal films of conjugated oligothiophene-phenylenes (OTP) structures from solutions and their characterization. In this work, the solvent vapor annealing method was adapted to obtain conjugated structures based on dihexyl- and dioctylbenzothienobenzothiophene (C6-BTBT and C8-BTBT) from dichlorobenzene and toluene solutions with a concentration of 0.06 to 0.80 g / l. Solutions of various concentrations were applied to silicon substrates by centrifugation and droplet method. According to microscopic studies, C8-BTBT single crystals of the required geometry and size of about 1 mm were grown from solutions in toluene with a concentration of less than 0.06 g / l by centrifugation at a speed of 800 rpm. Electrophysical measurements showed that the obtained crystals have hole conductivity with a fairly high carrier mobility up to 0.047 cm2 / V · s (average 0.03 cm2 / V · s), which makes it possible to use these materials for the manufacture of field effect transistors and other electronic devices based on them.
Dynamics of apatite and calcium silicate hydrate composites resorption in Tris-buffer
Authors: Solonenko A P , Blesman A I , Polonyankin D A 
Published: January 2020

Abstract
Composites based on several biocompatible inorganic compounds present oneself a class of promising materials that can be used to repair damaged areas of hard tissue. Development of these composites and their bioactivity establishing is paid a significant attention. Investigation of processes occurring at composite powder materials soaking based on poorly crystallized carbonate substituted hydroxyapatite and calcium silicate hydrate in Tris-buffer was performed in this work. Chemical composition analysis of solutions contacted with composites with varying calcium phosphate and calcium silicate contents was carried out. Examination of undissolved solid phases was performed by SEM, FTIR and LDA. The obtained results indicate that materials components gradually dissolve in Tris-buffer. Moreover, the samples resorption rate increases with the growth of calcium silicate hydrate content in materials composition. Precipitation of the apatite was repeatedly detected in experimental conditions; it designates a potentially high bioactivity of investigated synthetic mixtures.
The effect of boron nitride on the properties of rubber compounds
Authors: Zhansakova K S , Eremin E N , Russkikh G S , Kropotin O V 
Published: January 2020

Abstract
The work is devoted to research of vulcanization characteristics of mixtures and revealing of features of change of technological, dynamic and physical-mechanical properties of elastomers on the basis of isoprene rubber filled with carbon black N330 and boron nitride (BN). It has been established that with a gradual increase in the concentration of the inert filler BN a decrease in the curing rate by 33% and the density of the polymer cross-linking by 26% is observed, as well as an increase in the curing start time by almost 300% and the optimal curing time by 200%. At the same time, there is a 26% decrease in the "Payne effect", a 50% increase in the relative elongation at rupture and a 30% decrease in the tensile strength.
Mathematical Description of Solution of the Three-Dimensional Boundary Value Problem for the Stationary Magnetic Field in the Cylindrical Coordinate System
Authors: Andreeva E G , Tatevosyan A A 
Published: January 2020

Abstract
The paper proposes a method of forming a numerical projection-grid algorithm on a regular triangulation network for the calculation of three-dimensional models of the magnetic field of synchronous magnetoelectric generators with excitation from permanent magnets, using recurrent expressions obtained for the "regular element". The use of the" regular element "allows to automate the process of formation of a global system of linear algebraic equations in the projection-grid Galerkin method in combination with the finite element method, bypassing the stage of construction of" element " systems of equations.
Heat-mass exchange processes dynamics forecasting in fires in typical multistorey apartment buildings
Authors: Bedrina E A , Rekin A S , Khrapsky S F , Bokarev A I , Denisova E S 
Published: January 2020

Abstract
Heat-mass exchange dynamics forecasting in fires in typical multistorey buildings allows to prove the need and determine organizational and technical solutions parameters aimed to increasing such buildings residents safe evacuation probability, which is an urgent problem according to statistics on the deceased persons number of this population category as a result of fires. On the numerical studies results basis, the characteristic time changes regularities of critically dangerous fire factors for humans are established; the most dangerous factor according to the people safe evacuation possibility from these buildings is the optical smoke concentration level. A method for determining the critical smoke time for safe evacuation has been proposed. It is proposed to equip mass construction 5–9 storey apartment buildings with early fire detection and warning systems.
About the election strength criteria in calculations for long-term strength for non-isothermal processes of loading
Authors: Belov A V , Polivanov A A , Neumoina N G 
Published: January 2020

Abstract
In the paper the research methods of axially symmetric elastic - plastic stress strain state of structures in the form of thin single and multiple layer shells of rotation with an account of material damage at creep is represented. The long-term strength criterion definition, on the basis of which the time to failure of the structure is calculated, is one of the important task. There are multiple long-term strength criteria, but very little detail recommendations on their usage and concretizing, which is what makes this problem so difficult to solve. The authors proposed a simple and easy-to-use method for concretizing the Pisarenko–Lebedev generalized long-term strength criterion. To verify the reliability of the proposed method of concretizing the long-term strength criterion, the calculations of time to failure a cylindrical shell under the action of internal pressure and a thin lamina with a round hole stretched by external radial forces are carried out. The calculation results obtained by the proposed method differ from the experimental ones by 1.8% and 3.1%. These results are the most reliable. Therefore, proposed method for calculating the long-term strength criterion enables more accurate damage and time-to-rupture predictions, compared with other calculation methods.
Electro Steam Thermal Complex Powered by Wind-Driven Generator for the Treatment of the Oil Formation’s Bottomhole Area
Authors: Belsky A A , Dobush V S , Malarev V I 
Published: January 2020

Abstract
In this article authors propose application of the wind-driven power units as power source of bottomhole electric steam generator for the thermal high-viscosity oil reservoir stimulation. The structure of the electro steam thermal complex is proposed. An analysis of the wind energy potential in the areas where the largest high-viscosity oil deposits in Russia are located is carried out. As part of the complex under consideration, the type of the dependence of the bottomhole electric steam generator’s power on the formation depth has been established. The calculation of the required installed capacity of wind power plants for placement as part of the electro steam thermal complex at the largest high-viscosity oil deposits in Russia has been performed.
Electrical Complex for Autonomous Power Supply of Oil Leakage Detection Systems in Pipelines
Authors: Dobush V S , Belsky A A , Skamyin A N 
Published: January 2020

Abstract
The authors proposed a scheme of autonomous power supply for oil leakage detection systems in pipelines by applying the photovoltaic modules and thermoelectric generators as a power source. Laboratory experimental studies were carried out, the operating energy characteristics of the complex were obtained. A sufficient number of generating units has been determined for uninterrupted power supply to the data collection point of the oil leakage detection system.