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Ultra-high molecular weight polyethylene (UHMWPE) possesses distinctive properties, but has an extremely low melt flow rate (MFR) of about zero, which makes it unsuitable for processing by standard methods for polymers. The aim of this paper was to investigate the tribological properties of two-component UHMWPE-based composites with different content of isotactic PP. The composites were fabricated by three methods: a) hot pressing of the powder mixtures; b) hot compression of granules; and c) 3D printing (FDM). It was shown that the UHMWPE-based composites obtained by extrusion compounding (hot compression of granules and 3D printing) in terms of the mechanical and tribological properties (wear resistance, the friction coefficient, Young's modulus, and yield strength) were superior to the ones manufactured by hot pressing of the powder mixtures. The most effective was the ‘UHMWPE+20% PP’ composite in terms of maintaining high tribological and mechanical properties and the necessary melt flow rate (MFR) in a wide range of loads. It was recommended as a feedstock for additive manufacturing of complex-shaped products (joint components) for friction units in orthopedics.

The paper explores the products made of acrylonitrile butadiene styrene (ABS), a common thermoplastic polymer comprising up to 10 wt.% carbon fibers. These products are obtained by extrusion-based 3D printing. The mechanical properties of the obtained specimens are studied by tensile and flexural strength testing with regard to the carbon fiber content. The scanning electron microscopy is used to study the structure of the fracture surface of the tested specimens. The physical-and-mechanical properties of polymer specimens and products produced therefrom are investigated with respect to the different content of carbon fibers. Secondary ABS polymer subjected to natural ageing for 17000 hours is used to prepare the composite material. Described are the production techniques for the composite filament and the filament fabrication process, which is optimum from the viewpoint of achieving the improved properties of physical-and-mechanical properties of the specimens obtained.

We have studied the effect of surface lamp processing on the hydrogen permeability of membrane foil produced by rolling an ingot of a Pd–Cu solid solution. Such processing has been shown to remove sorption products from the membrane surface and to significantly improve the hydrogen permeability of the membranes at temperatures of up to 300°C. The use of a reactor with a cleaned PdCu membrane allows the hydrogen yield in the methanol steam reforming process in the presence of a Ni0.2Cu0.8/Ce0.3Zr0.7O2–δ catalyst to be raised relative to that in a conventional flow reactor owing to the displacement of thermodynamic equilibrium as a result of the removal of hydrogen from the reaction zone. The effect of membrane surface cleaning by lamp processing is most clearly demonstrated by examining the yield of high-purity hydrogen in the permeate zone. Whereas at 360°C the yield of high-purity hydrogen in a reactor containing a membrane with a cleaned surface increased by just 15%, membrane surface cleaning by lamp processing ensured a 15‑fold gain at 260°C. This is due to the considerable difference between the hydrogen permeabilities of the membranes at low temperatures and its gradual decrease at high temperatures.

Surface modification of GaAs in sulfur vapor by different procedures and subsequent annealing and thermal oxidation have an advantageous effect on the properties of heterostructures, ensuring binding of the constituent components of the substrate and the formation of films with a uniform surface, without well-defined defects. The approaches proposed in this work allow films of nanometer thickness with resistivity from ~108 to ~1010 Ω cm to be grown on the surface of GaAs by a simple method.

This contribution deals with the analysis of the positioning accuracy of a new Nano Fabrication Machine. This machine uses a planar direct drive system and has a positioning range up to 100 mm in diameter. The positioning accuracy was investigated in different movement scenarios, including phases of acceleration and deceleration. Also, the target position error of certain movements at different positions of the machine slider is considered. Currently, the NFM-100 is equipped with a tip-based measuring system. This Atomic Force Microscope (AFM) uses self-actuating and self-sensing microcantilevers, which can be used also for Field-Emission-Scanning-Probe-Lithography (FESPL). This process is capable of fabricating structures in the range of nanometres. In combination with the NFM-100 and its positioning range, nanostructures can be analysed and written in a macroscopic range without any tool change. However, the focus in this article is on the measurement and positioning accuracy of the tip-based measuring system in combination with the NFM-100 and is verified by repeated measurements. Finally, a linescan, realised using both systems, is shown over a long range of motion of 30 mm.

X-ray diffraction has been used to study the phase composition and determine the lattice parameter of the β- and α-phases in foil of a Pd–Cu solid solution with a composition that ensures reversibility of the β $$ \rightleftarrows $$ α transformations: with the structure of the β- and α-phases and a two-phase structure. The thermal expansion coefficient of the Pd–Cu solid solution has been determined for the first time.

We have studied the phase composition and texture of a Pd–Cu solid solution with a nearly equiatomic composition in different steps of the preparation of membrane foil by rolling to 300, 175, 100, and 20 μm and 7-μm-thick foil produced by magnetron sputtering of a target having the same composition as the foil. We have identified orientation relationships between the β- and α-phases in the as-prepared two-phase structures and demonstrated that, after heating to 600°C and subsequent cooling, the ordered solid solutions (β-phase) prepared by the two processes, have identical textures, which can be understood in terms of the transformation mechanism.

The effectiveness of flash lamp processing and ion beam sputtering in surface cleaning of membrane foil from a Pd–Cu solid solution produced by rolling has been assessed using cyclic voltammetry and atomic force microscopy. It has been shown that it is reasonable to use cyclic voltammetry for assessing the degree of foil surface cleaning and that combined surface processing of membrane foil is effective in foil surface cleaning. Ion beam processing reproducing the surface elemental composition corresponding to the original composition of the solid solution and increasing surface roughness is a factor of 1.3 more effective than combined surface processing.

The β $$ \rightleftarrows $$ α phase transformations in foil of the Pd–52 at % Cu solid solution prepared by rolling have been studied using X-ray diffractometry and resistivity measurements during thermal heating–cooling cycles or lamp processing (LP) using light from high-power pulsed xenon lamps, followed by cooling. The results demonstrate that complete ordering of the two-phase (α + β) as-prepared (as-rolled) foil follows the sequence (α + β) → β → α → β in the first heating–cooling cycle and β → α → β in the second and subsequent cycles. When a radiative energy critical for a given thickness of foil with an ordered structure is delivered to the foil surface, an irreversible β → α phase transformation occurs, whose rate can be three orders of magnitude higher than the rate characteristic of the disordering process during Joule heating. After LP, the reversibility of the β $$ \rightleftarrows $$ α phase transformations, inherent in the initial, ordered structure, is observed in a second thermal cycle: heating to 700°C and cooling. The sequence of phase transitions is α → β → α → β in the first cycle and β → α → β in the second and subsequent cycles. The localization of light in the skin layer and finite thermal conductivity offer the possibility of producing a structure with a phase composition gradient at subcritical irradiation times. The fact that the LP-stabilized α-phase persists up to 300°C makes it possible to compare the mechanical properties of foil samples having identical elemental compositions but different (ordered and disordered) structures.

—A comparative analysis of the structural, tribological, and mechanical properties of polymer–polymer composites with the optimized composition UHMWPE + 15 wt % HDPE-g-SMA + 15 wt % PP, obtained by FDM (fused deposition modeling) and compressive sintering (hot-pressing) methods has been performed. It is shown that the tribomechanical characteristics (wear resistance, friction coefficient, elasticity modulus, yield limit, strength, elongation at break) of 3D-printed extrudable polymer–polymer UHMWPE composites exceed those of hot-pressed composites due to a more homogeneous supramolecular structure with enlarged crystallinity. Tribotests of extrudable UHMWPE composites in different friction modes (PV) demonstrates their applicability in joints operating in a wide range of loads and sliding rates.

The necessary composition and content of fillers of a multicomponent extrudable composition based on an ultrahigh-molecular polyethylene (UHMPE) with specified mechanical and tribotechnical characteristics are determined. For the purpose of effective and operational development of extrudable composites based on an UHMPE, a minimum amount of experimental data and an algorithm for determining the governing parameters (formulations) is used, which give the needed (restrictive) values for the effective characteristics of multicomponent polymer-polymer compositions. This allows one to secure the tribological, mechanical and technological properties required. The limited amount of experimental data for the relation between the effective properties and the formulation required is supplemented by values calculated using the Lagrange interpolation polynomial. The relations obtained are represented as surfaces and the corresponding level lines. The imposition of level lines allows one to determine the area that meets the requirements specified and to find the formulation necessary for it. On the basis of this algorithm, the optimum formulation of a three-component mixture consisting of an UHMPE, a high-density polyethylene grafted with maleic anhydride, and a polypropylene having tribomechanical properties at the level of an UHMPE, but with a melt flow-behavior index suitable for 3D printing by fused deposition modeling, is determined. According to the formulation found, samples were made and tested, and they completely satisfied the properties prescribed.

The article presents the materials of examinations carried out during a full-scale examination of the process of splicing a steel rope, conducting a magnetic defectoscopy and subsequent observations of the performance of a steel rope at the ski resorts of Krasnaya Polyana. The results of studies of the causes of the formation of “waviness” defects in the splicing section of the steel rope, as well as defects in the form of wire breakage of the steel rope in the splicing section and a defect in reducing and increasing the diameter of the steel rope in the splicing section are presented.

This article is devoted to studying morphological, structural, and orientation transformations and variations of elemental composition during growth of films of Pd–Pb solid solution upon magnetron sputtering of Pd–5 at % Pb target in an Ar environment (10–1 Pa); the initial vacuum is 10–3 Pa; growth rate is 4 nm/s; magnetron power during growth of thin films is 630–650 W and of thick films is 750–790 W. It is established that nucleation and growth of films of Pd–Pb solid solution take place according to the Volmer–Weber growth mode and are accompanied by collective recrystallization. The stage of labyrinth morphology is achieved at an average thickness of 10 nm. This stage is characterized by nanocrystalline structure and uniaxial texture 〈 111〉 . Existence of the second component (Pb) suppresses multiple twinning peculiar to Pd island films. The elemental composition in the film bulk is characterized by a decrease in Pb concentration.

In accordance with the orientation ratio (110), [001]β || (111), [$$1\bar {1}0$$]α established by fast electron diffraction between the ordered (β) and disordered (α) phases in the foil of a Pd + 57 at % Cu solid solution, the atomic structure of the interface is modeled by molecular dynamics. It is found that the structural and size discrepancies are compensated by interfacial dislocations with Burgers vectors a/2〈111〉 in coordinates of the β-phase.

The results related to the application of two-component solid-lubricant coatings — molybdenum disulfide (MoS2 ), tungsten disulfide (WS2 ) under vibration conditions are presented.

transformations in a thin ~4 m foil of PdCu solid solution were investigated by x-ray diffractometry and measurement of electrical resistance in heating-cooling cycles during thermal or rapid photon treatment by radiation of high-power pulsed xenon lamps. It has been found that a single rapid photon treatment for 0,3 s (the energy dose of the radiation entering the sample is 10 j cm‑2) leads to a complete disordering of the solid solution at a rate 400 times greater than in the heat treatment mode used (heating at a rate of 15 K min‑1).

The effects of rock inherent heterogeneity and grain size on hydraulic fracture initiation and propagation for different propagation regimes are investigated through two dimensional discrete element modeling. Random particle assembly is used to mimic rock inherent heterogeneity in the numerical model while regular particle assembly is used as the reference. The rock inherent heterogeneity mainly affects the hydraulic fracture net pressure in the viscosity dominated regime and the effect is more profound in the toughness dominated regime. In the toughness dominated regime, in addition to the increase of net pressure relative to the regular particle sample, the hydraulic fracture profiles in the random particle sample also show larger tortuosity and asymmetry caused by the local heterogeneity, and the fracture growth of one of the wings can be temporarily arrested. Numerical simulations show that the effective toughness of the random particle sample is larger than that of the regular particle sample. This is caused by tortuosity, in which case the net pressure in the random particle sample is also affected by the local geometrical arrangements of the particles. Also, the apparent toughness is influenced by the magnitude of initial stress, which comes in addition to the tensile strength of the contact bond and the particle radius. The effect of stress anisotropy has limited effect on the hydraulic fracture propagation for both the viscosity and toughness dominated regimes.

Предложена методика модифицирования InP в парах серы, методом локального рентгеноспектрального микроанализа подтверждено её наличие на поверхности. Дляплёнок нанометрового диапазона толщины (до 50 нм), выращенных термическим оксидированием InP с предварительно обработанной в парах серы поверхностью, методом Оже-электронной спектроскопии установлено послойное распределение компонентов. По данным атомно-силовой микроскопии модифицирование InP серой приводит к формированию поверхности с зернистой структурой, более упорядоченной по сравнению с эталоном (собственное термооксидирование фосфида индия). Несмотря на то, что в результирующих плёнках сера не обнаружена, они обладают полупроводниковыми свойствами, тогда как для собственных оксидных слоёв на InP характерна омическая проводимость REFERENCES Markov V. F., Mukhamedzyanov Kh. N., Maskaeva L. N. Materialy sovremennoj jelektroniki [Materials of modern electronics]. Ekaterinburg, Publishing Ural. un-one, 2014, 272 p. (in Russ.) Oktyabrsky S. Fundamentals of III-V Semiconductor MOSFETs. Springer Science LCC, 2013, 447 p. Bessolov V. N., Lebedev M. V. Hal’kogenidnaja passivacija poluprovodnikov AIIIBV [Chalcogenide passivation of III–V semiconductor surfaces]. Semiconductors, 1998, v. 32(11), pp. 1141–1156. https://doi.org/10.1134/1.1187580 Mittova I. Ya., Soshnikov M., Terekhov V. A., Semenov V. N. Termicheskoe oksidirovanie geterostruktur V2S5/InP v kislorode [Thermal oxidation of V2S5/InP heterostructures in oxygen]. Inorganic Materials, 2000, v. 36(10), pp. 975–978. https://doi.org/10.1007/BF02757971 Yoshida N., Chichibu S., Akane T., Totsuka M., Uji H., Matsumoto S., Higuchi H. Surface passivation of GaAs using ArF excimer laser in a H2S gas ambient. Applied Physics Letters, 1993, v. 63(22), pp. 3035–3037. https://doi.org/10.1063/1.110250 Liu K. Z., Shimomura M., Fukuda Y. Band Bending of n-GaP(001) and p-InP(001) Surfaces with and without sulfur treatment studied by Photoemission (PES) and Inverse Photoemission Spectroscopy (IPES). Advanced Materials Research, 2011, v. 222, pp. 56–61. https://doi.org/10.4028/www.scientific.net/AMR.222.56 Tian Sh., Wei Zh., Li Y., Zhao H., Fang X. Surface state and optical property of sulfur passivated InP. Materials Science in Semiconductor Processing, 2014, v. 17, pp. 33–37. https://doi.org/10.1016/j.mssp.2013.08.008 Sundararaman C. S., Poulin S., Currie J. F., Leonelli R. The sulfur-passivated InP surface. Canadian Journal of Physics, 2011, v. 69(3–4), pp. 329–332. https://doi.org/10.1139/p91-055 Lau W. M., Kwok R. W. M., Ingrey S. Controlling surface band-bending of InP with polysulfi de treatments. Surface Science, 1992, v. 271(3), pp. 579–586. https://doi.org/10.1016/0039-6028(92)90919-W Tao Y., Yelon A., Sacher E., Lu Z. H., Graham M. J. S-passivated InP (100)-(1×1) surface prepared by a wet chemical process. Applied Physics Letters, 1992, v. 60(21), pp. 2669–2671. https://doi.org/10.1063/1.106890 Chasse T., Peisert H., Streubel P., Szargan R. Sulfurization of InP(001) surfaces studied by X-ray photoelectron and X-ray induced Auger electron spectroscopies (XPS/XAES). Surface Science, 1995, v. 331–333, pp. 434–440. https://doi.org/10.1016/0039-6028(95)00306-1 Maeyama S., Sugiyama M., Heun S., Oshima M. Electron J. (NH4)2Sx-treated InP(100) surfaces studied by soft x-ray photoelectron spectroscopy. Journal of Electronic Materials, 1996, v. 25(5), pp. 593–596. https://doi.org/10.1007/BF02666509 Sugahara H., Oshima M., Klauser R. Bonding states of chemisorbed sulfur atoms on GaAs. Surface Science, 1991, v. 242(1–3), pp. 335–340. https://doi.org/10.1016/0039-6028(91)90289-5 Koebbel A., Leslie A., Dudzik E., Mitchell C. E. J. X-ray standing wave study of wet-etch sulphur-treated InP 100 surfaces. Applied Surface Science, 2000, v. 166(1–4), pp. 196–200. https://doi.org/10.1016/S0169-4332(00)00413-X Nelson A. J., Frigo S. P., Rosenberg R. Soft x-ray photoemission characterization of the H2S exposed surface of p-InP. Journal of Applied Physics, 1992, v. 71(12), pp. 6086–6089. https://doi.org/10.1063/1.350415 Nelson A. J., Frigo S. P., Rosenberg R. Surface type conversion of InP by H2S plasma exposure: A photoemission investigation. Journal of Vacuum Science & Technology A, 1993, v. 11(4), pp. 1022–1027. https://doi.org/10.1116/1.578807 Kwok R. W. M., Lau W. M. X-ray photoelectron spectroscopy study on InP treated by sulfur containing compounds. Journal of Vacuum Science & Technology A, 1992, v. 10(4), pp. 2515–2520. https://doi.org/10.1116/1.578091 Wang X., Weinberg W. H. Structural model of sulfur on GaAs(100). Journal of Applied Physics, 1994, v. 75(5), pp. 2715–2717. https://doi.org/10.1063/1.356203 Berkovits V. L., Paget D. Optical study of surface dimers on sulfur-passivated (001)GaAs. Applied Physics Letters, 1992, v. 61(15), pp. 1835–1837. https://doi.org/10.1063/1.108390 Bessolov V. N., Konenkova E. V., Lebedev M. V. Sulfi dization of GaAs in alcoholic solutions: a method having an impact on effi ciency and stability of passivation. Materials Science and Engineering: B, 1997, v. 44(1–3), pp. 376–379. https://doi.org/10.1016/S0921-5107(96)01816-8 Sladkopevtsev B. V., Mittova I. Ya., Tomina E. V., Burtseva N. A. Growth of vanadium oxide fi lms on InP under mild conditions and thermal oxidation of the resultant structures. Inorganic Materials, 2012, v. 48(2), pp. 161–168. https://doi.org/10.1134/S0020168512020173 Tretyakov N. N., Mittova I. Ya., Sladkopevtcev B. V., Samsonov A. A. Vlijanie magnetronno napylennogo sloja MnO2 na kinetiku termooksidirovanija InP, sostav i morfologiju sintezirovannyh plenok [The effect of the magnetron-deposited MnO2 layer on the InP thermal oxidation kinetics, composition and morphology of the synthesized fi lms]. Inorganic Materials, 2017, v. 53(1), pp. 41–48. https://doi.org/10.7868/S0002337X17010171 (in Russ.)

In order to develop dispensable materials for additive manufacturing technologies, the structural and functional analysis of antifrictional polymer-polymer blends based on ultrahigh-molecular weight polyethylene (UHMWPE) are performed. The problem of the optimal selection of polymer plasticizers from the commercially available thermoplastic is solved in order to improve the extrudability of UHMWPE. It is shown that the effective plasticizing filler for UHMWPE from the standpoint of maintaining its tribological and mechanical characteristics and providing the required melt flow index is a double mixture of 10 wt % HDPE-g-SMA + 10 wt % PP. Using the developed materials will make it possible to manufacture parts of a complex shape for tribojoints, including endoprostheses, by the 3D printing method.

The aim of the paper was to improve the functional properties of composites based on ultra-high molecular weight polyethylene (UHMWPE) by loading with reinforcing fibers. It was achieved by designing the optimal composition for its subsequent use as a feedstock for 3D-printing of guides for roller and plate chains, conveyors, etc. As a result, it was experimentally determined that loading UHMWPE with 17% high density polyethylene grafted with VinylTriMethoxySilane (HDPE-g-VTMS) was able to bind 5% glass fillers of different aspect ratios, thereby determining the optimal mechanical and tribological properties of the composites. Further increasing the content of the glass fillers caused a deterioration in their tribological properties due to insufficient adhesion of the extrudable matrix due to the excessive filler loading. A multi-level approach was implemented to design the high-strength anti-friction ‘UHMWPE+17%HDPE-g-VTMS+12%PP’-based composites using computer-aided algorithms. This resulted in the determination of the main parameters that provided their predefined mechanical and tribological properties and enabled the assessment of the possible load-speed conditions for their operation in friction units. The uniform distribution of the fillers in the matrix, the pattern of the formed supermolecular structure and, as a consequence, the mechanical and tribological properties of the composites were achieved by optimizing the values of the main control parameters (the number of processing passes in the extruder and the aspect ratio of the glass fillers).

This paper focuses on a new Nano Fabrication Machine 100 (NFM-100) with a working range up to 100 mm in diameter and its integrated tip-based system, which can be used as an Atomic Force Microscope (AFM) as well as for Field-Emission-Scanning-Probe-Lithography (FESPL). The combination of both systems offers the possibility to fabricate and analyze micro- and nanostructures with high resolution and precision down to a single nanometer over a large area in one single configuration without tool or sensor change. After the description of the basic machine structure of the NFM-100, the demonstration of long range and large area AFM scans in combination with the NFM-100 will be shown. Additionally, the basic functionality of the FESPL manufacturing process is presented.

The focus of this work lies on investigations on a new Nano Fabrication Machine (NFM-100) with a mounted atomic force microscope (AFM). This installed tip-based measuring system uses self-sensing and self-actuated microcantilevers, which can be used especially for field-emission scanning probe lithography (FESPL). The NFM-100 has a positioning range of Ø 100 mm, which offers, in combination with the tip-based measuring system, the possibility to analyse structures over long ranges. Using different gratings, the accuracy and the reproducibility of the NFM-100 and the AFM-system will be shown.

It is believed that the structure and properties of parts fabricated by additive (i.e., non-stationary) manufacturing are slightly worse compared to hot pressing. To further proceed with improving the quality of Fused Deposition Modeling 3D-printed parts, the &lsquo, UHMWPE + 17 wt.% HDPE-g-SMA + 12 wt.% PP&rsquo, composite feedstock fabrication parameters, by the twin-screw extruder compounding and 3D printing (the Fused Deposition Modeling (FDM) process), were optimized using the Taguchi method. The optimization was carried out over the results of mechanical tests. The obtained results were interpreted in terms of (1) the uniformity of mixing of the polymer components upon compounding and (2) the homogeneity of the structure formed by the 3D printing. The values of the main factors (the processing parameters) were determined using the Taguchi method. Their application made it possible to improve the physical, mechanical, and tribological properties of the samples manufactured by the FDM method at the level of neat UHMWPE as well as the UHMWPE-based composites fabricated by compression sintering. A comparative analysis of the structure, as well as the mechanical and tribological properties of the composite obtained by the FDM method, and the hot pressing from &lsquo, optimized&rsquo, feedstock was performed. The &lsquo, composites fabricated by the optimal compounding and 3D printing parameters can be implemented for the additive manufacturing of complex shape products (including medical implants, transport, mining, and processing industries, in particular, in the Far North).

In this research we introduce a plasmonic nanoparticle based optical biosensor for monitoring of molecular binding events. The sensor utilizes spotted gold nanoparticle arrays as sensing platform. The nanoparticle spots are functionalized with capture DNA sequences complementary to the analyte (target) DNA. Upon incubation with the target sequence, it will bind on the respectively complementary functionalized particle spot. This binding changes the local refractive index, which is detected spectroscopically as the resulting changes of the localized surface plasmon resonance (LSPR) peak wavelength. In order to increase the signal, a small gold nanoparticle label is introduced. The binding can be reversed using chemical means (10 mM HCl). It is demonstrated that multiplexed detection and identification of several fungal pathogen DNA sequences subsequently on one sensor array are possible by this approach.

The phase and structural transformations that Pd–Ru(7 at %) solid solution thin films undergo during thermal oxidation in oxygen in the temperature range 570–1070 K are studied by transmission electron microscopy, high-energy electron diffraction, and reflection high-energy electron diffraction. With increasing oxidation temperature, the phase composition is found to change in the order: Pd–Ru(7 at %) solid solution → Pd–Ru(7 at %) + PdO + RuO2 → PdO + RuO2 → PdO–RuO2 solid solution. We show that the complete oxidation of Pd–Ru(7 at.%) thin films to form single-phase films of the PdO–RuO2 solid solution takes place at a temperature of 100 K higher compared to pure palladium films. The resistance sensor response of the prepared PdO−RuO2 oxide films to ozone in air is studied for the first time. The results suggest that this is a promising material for use in gas-sensing applications.

Although the field of optical lithography is highly investigated and numerous improvements are made, structure sizes smaller than 20 nm can only be achieved by considerable effort when using conventional technology. To cover the upcoming tasks in future lithography, enormous exertion is put into the development of alternative fabrication technologies in particular for micro- and nanotechnologies that are capable of measuring and patterning at the atomic scale in growing operating areas of several hundred square millimetres. Many new technologies resulted in this process, and are promising to overcome the current limitations1, 2, but most of them are demonstrated in small areas of several square micrometers only, using state-of-the-art piezo stages or the like. At the Technische Universitat Ilmenau, the NanoFabrication Machine 100 (NFM-100) was developed, which serves as an important experimental platform for basic research in the field of scale-spanning AFM tip-based and laser-based nanomeasuring and nanofabrication for simultaneous subnanometre measuring and structuring on surfaces up to O100 mm. This machine can be equipped with several probing systems like AFM, laser focus probes and 3D-micro probes as well as tools for different nanofabrication technologies like tip-based technologies, optical technologies and mechanical two-dimensional technologies in a large working range with subnanometre reproducibility and uncertainty. In this paper, the specifics and advantages of the NFM-100 will be described as well as nanofabrication technologies that are currently worked on e.g. advanced scanning proximal probe lithography based on Fowler-Nordheim-electron-field emission, direct laser writing and UV-nanoimprint lithography.

Одним из подходов к формированию функциональных наноразмерных плёнок на поверхности AIIIBV является хемостимулированное термооксидирование. Для получения требуемого результата необходимо обоснованно выбрать объект, который может выступать в роли хемостимулятора процесса или модификатора структуры и свойств формируемых в результате оксидирования плёнок. Использование сложных соединений, способных совмещать обе эти функции, представляется перспективным. Цель статьи – исследование воздействия наноразмерных слоев хемостимулятора-модификатора Mn3(P0.1V0.9O4)2 на процесс термического оксидирования GaAs, состав и морфологиюформируемых пленок.Объект исследования – арсенид галлия (100) с нанесёнными на его поверхность наноразмерными слоями ванадат-фосфата марганца Mn3(P0.1V0.9O4)2. С целью увеличения скорости процесса и обеспечения высокой химической гомогенности продукта предлагается микроволновая активация синтеза хемостимулятора-модификатора Mn3(P0.1V0.9O4)2 и дальнейшее его нанесение на поверхность полупроводника методом spin-coating. Сформированные гетероструктуры Mn3(P0.1V0.9O4)2/GaAs термически оксидировали в интервале температур 490–550 oС в течение 60 минут в потоке кислорода.Осуществляли контроль толщины растущих плёнок (методами лазерной и спектральной эллипсометрии), их состав (рентгенофазовый анализ, Оже-электронная спектроскопия) и морфологию поверхности (атомно-силовая микроскопия).Исследования кинетики термооксидирования гетероструктур Mn3(P0.1V0.9O4)2/GaAs показали, что определяющим процессом является твердофазная реакция, лимитируемая диффузией в твердой фазе, и реализуется транзитный характер действия хемостимулятора без каталитического эффекта. Выявлено, что ванадат-фосфат марганца способствует увеличению прироста формируемой пленки в среднем на 70–220% по сравнению с эталонным оксидированием GaAs, приводит к интенсификации вторичных взаимодействий оксидов компонентов подложки с продуктами термолиза Mn3(P0.1V0.9O4)2 и отсутствию сегрегации мышьяка в плёнке в неокисленном состоянии.При термооксидировании гетероструктур Mn3(P0.1V0.9O4)2/GaAs формируются наноразмерные (50-200 нм) плёнки с достаточно выраженным рельефом. Необходимо дальнейшее исследование электрофизических характеристик плёнок, т. к. данные о составе позволяют предположить их диэлектрический характер. Это может быть использовано на практике для формирования на поверхности AIIIBV плёнок функционального назначения с варьируемыми в широких пределах характеристиками. ЛИТЕРАТУРА Tang M., Park J.-S., Wang Z., Chen S., Jurczak P., Seeds A., Liu H. Integration of III-V lasers on Si for Si photonics. Progress in Quantum Electronics. 2019;66: 1–18. DOI: https://doi.org/10.1016/j.pquantelec.2019.05.002 Torkhov N. A., Babak L. I., Kokolov A. A. On the application of Schottky contacts in the microwave, extremely high frequency, and THz ranges. Semiconductors. 2019;53: 1688–1698. DOI: https://doi.org/10.1134/S1063782619160280 Lutz J., Schlangenotto H., Scheuermann U., De Doncker R. Semiconductor power devices. Physics, characteristics, reliability. Springer-Verlag Berlin Heidelberg; 2018. 714 р. DOI: https://doi.org/10.1007/978-3-319-70917-8 Yadav S., Rajan C., Sharma D., Balotiya S. GaAs-SiGe based novel device structure of doping less tunnel FET. In: Sengupta A., Dasgupta S., Singh V., Sharma R., Kumar Vishvakarma S. (eds.) VLSI Design and Test. VDAT 2019. Communications in computer and information science, vol. 1066. Singapore: Springer; 2019. p. 694–701. DOI: https://doi.org/10.1007/978-981-32-9767-8_57 Klotzkin D. J. Semiconductors as laser materials 1: Fundamentals. In: Introduction to semiconductor lasers for optical communications. Springer, Cham; 2020. p. 31–52. DOI: https://doi.org/10.1007/978-3-030-24501-6_3 Paswan R. K., Panda D. K., Lenka T. R. Dielectric Modulated AlGaAs/GaAs HEMT for label free detection of biomolecules. In: Sharma R., Rawal D. (eds.) The physics of semiconductor devices. IWPSD 2017. Springer proceedings in physics, vol. 215. Springer, Cham; 2017. p. 709–715. DOI: https://doi.org/10.1007/978-3-319-97604-4_109 Eichler H. J., Eichler J., Lux O. Semiconductor lasers. In: Lasers. Springer Series in Optical Sciences, vol. 220. Springer, Cham; 2018. p. 165–203. DOI: https://doi.org/10.1007/978-3-319-99895-4_10 Mikhailova M. P., Moiseev K. D., Yakovlev Y. P. Discovery of III–V semiconductors: physical properties and application semiconductors. Semiconductors. 2019;53(3): 273–290. DOI: https://doi.org/10.1134/S1063782619030126 Анфертьев В. А., Вакс В. Л., Реутов А. И., Баранов А. Н., Teissier R. Изучение частотных характеристик ТГц квантовых каскадных лазеров с использованием открытого оптического резонатора. Журнал радиоэлектроники. 2018;12: 14–24. DOI: https://doi.org/10.30898/1684-1719.2018.12.5 Pawar S. A., Kim D., Kim A., Park J. H., Shin J. C., Kim T. W., Kim H. J. Heterojunction solar cell based on n-MoS2/p-InP. Optical Materials. 2018;86: 576–581. DOI: https://doi.org/10.1016/j.optmat.2018.10.052 Sugiyama H., Uchida K., Han X., Periyanayagam G. K., Aikawa M., Hayasaka N., Shimomura K. MOVPE grown GaInAsP/GaInAsP SCH-MQW laser diode on directly-bonded InP/Si substrate. Journal of Crystal Growth. 2019;507: 93–97. DOI: https://doi.org/10.1016/j.jcrysgro.2018.10.024 Sharma S. K., Singh S. P., Kim D. Y. Fabrication of the heterojunction diode from Y-doped ZnO thin fi lms on p-Si substrates by sol-gel method. Solid State Communications. 2018;270: 124–129. DOI: https://doi.org/10.1016/j.ssc.2017.12.010 Asalzadeh S., Yasserian K. The effect of various annealing cooling rates on electrical and morphological properties of TiO2 thin fi lms. Semiconductors. 2019;53: 1603–1607. DOI: https://doi.org/10.1134/S1063782619160036 Томина Е. В., Миттова И. Я., Сладкопевцев Б. В., Кострюков В. Ф., Самсонов А. А., Третьяков Н. Н. Термическое оксидирование как способ создания наноразмерных функциональных пленок на полупроводниках AIIIBV: хемостимулирующее воздействие оксидов металлов : обзор. Конденсированные среды и межфазные границы. 2018;20(2): 184–203. DOI: https://doi.org/10.17308/kcmf.2018.20/522 Liu H. A short review on thermal vapor sulfurization of semiconductor thin fi lms for optoelectronic applications. Vacuum. 2018;154; 44–48. DOI: https://doi.org/10.1016/j.vacuum.2018.04.050 Миттова И. Я., Сладкопевцев Б. В., Томина Е. В., Самсонов А. А., Третьяков Н. Н., Пономаренко С. В. Синтез диэлектрических пленок термооксидированием MnO2/GaAs. Неорганические материалы. 2018;54(11): 1149–1156. DOI: https://doi.org/10.1134/S0002337X18110106 Housecroft C., Sharpe A. G. Inorganic chemistry (4th ed.). Издательство: Pearson; 2012. 1213 р. Миттова И. Я., Томина Е. В., Лапенко А. А., термическом окислении GaAs с поверхностью, модифицированной ванадием. Неорганические материалы. 2004;40(5): 519–523. Spicer W. E., Lindau I., Skeath P., Su C. Y., Chye P. Unifi ed mechanism for Schottky-barrier formation and III-V oxide inter-face states. Physical Review Letters. 1980;44: 420. DOI: https://doi.org/10.1103/PhysRevLett.44.420 Томина Е. В., Миттова И. Я., Бурцева Н. А., Сладкопевцев Б. В. Способ синтеза люминофора на основе ортованадата иттрия: Патент № 2548089 РФ. Заявл. 12.11.2013. Опубл. 20.05.2015. Бюл. №2013133382/05. Брандон Д., Каплан У. Микроструктура материалов. Методы исследования и контроля. М.: Техносфера; 2004. 384 с. Popielarski P., Mosinska L., Bala W., Paprocki K., Zorenko Yu., Zorenko T., Sypniewska M. Persistent photoconductivity in ZnO thin fi lms grown on Si substrate by spin coating method. Optical Materials. 2019;97: 109343. DOI: https://doi.org/10.1016/j.optmat.2019.109343 Feng C., Zhang Y., Liu J., Qian Y., Bai X. Optimized chemical cleaning procedure for enhancing photoemission from GaAs photocathode. Materials Science in Semiconductor Processing. 2019;91: 41–46. DOI: https://doi.org/10.1016/j.mssp.2018.11.003 Mittova I. Ya., Tomina E. V., Sladkopevtsev B. V., Tret’yakov N. N., Lapenko A. A., Shvets V. A. Highspeed determination of the thickness and spectral ellipsometry investigation of fi lms produced by the thermal oxidation of InP and VXOY/InP structures. Inorganic Materials. 2013;49(2): 179–184. Костюхин Е. М. Синтез наночастиц магнетита в условиях микроволнового и конвекционного нагрева. Журнал физической химии. 2018;92(12): 1875–1878. DOI: https://doi.org/10.1134/S0044453718120233 Черепов В. В., Кропачев А. Н., Будин О. Н. Перспективы развития способов синтеза титанатов перовскитоподобной структуры и допирования их редкоземельными элементами. Известия высших учебных заведений. Цветная металлургия. 2018;6: 31–41. DOI: https://doi.org/10.17073/0021-3438-2018-6-31-41 Kuznetsova V. A., Almjasheva O. V., Gusarov V. V. Infl uence of microwave and ultrasonic treatment on the formation of CoFe2O4 under hydrothermal conditions. Glass Physics and Chemistry. 2009;35(2): 205–209. DOI: https://doi.org/10.1134/S1087659609020138 Третьяков Ю. Д. Развитие неорганической химии как фундаментальной основы создания новых поколений функциональных материалов. Успехи химии. 2004;73(9): 899–914. Красненко Т. И., Самигуллина Р. Ф., Ротермель М. В., Николаенко И. В., Зайцева Н. А., Ищенко А. В., Онуфриева Т. А. Влияние способа синтеза на морфологические и люминесцентные характеристики a-Zn2V2O7. Журнал неорганической химии. 2017;62(3): 263–268. DOI: https://doi.org/10.7868/S0044457X17030114 JCPDC PCPDFWIN: A Windows Retrieval/Display program for Accessing the ICDD PDF – 2 Data base. International Centre for Diffraction Data; 1997. Хорохордина А. О. Твердофазные процессы при

Composite membranes with a thin selective layer based on the Pd–46 at % Cu or Pd–5 at % Pb solid solution on the surface of a bilayer heterostructure with two-level porosity in the form of Kh18N10T steel/nanoporous titanium oxide (steel/rutile) are fabricated. The structure of the selective 4-μm-thick layer is found to have no through pores, and a metal does not penetrate into the nanopores in titanium oxide. The selective layer in both versions has a fine submicrocrystalline granular structure, which is caused by the presence of a second component in the Pd–Pb layer and by a two-phase composition of the Pd–Cu layer. In the temperature range 200–300°C, the hydrogen permeability of the membrane based on the two-phase Pd–Cu solid solution is higher than the membrane based on the Pd–Pb solid solution by a factor of 1.7–2.0.

Three-dimensional distinct element code is utilized to study hydraulic fracture propagation and proppant transport in a two-layer formation with stress drop. The fracture is initiated in the primary layer with high stress and propagates upwards into the low stress layer in the viscosity dominated regime. The hydro-mechanical coupling causes pinching and smaller aperture at the interface between the stress layers. The results indicate that the pinching at the stress interface can greatly affect the proppant transport. Critical proppant size can be defined above which the proppant is blocked and cannot enter the low stress zone. Large sized proppant could further intensify the pinching effect because the screen out leads decreased fluid supply to the low stress zone. Small sized proppant, on the other hand, could ease the pinching by increasing viscosity of the slurry relative to clean fluid. In order to have an ability to determine the critical proppant size, we have developed a relation between the dimensionless pinching aperture and the dimensionless stress for viscosity dominated fractures. This relation can be applied to estimate the pinching aperture for any given injection and rock parameters, and to provide guidelines for selecting optimal proppant size in the field operations for cases of controlling fracture height growth in the vertical direction and optimizing the extent of fracture lateral propagation when carrying out the infill well fracturing.

This study investigates the relation between two approaches for modeling fracture propagation. The first one is the classical approach, in which fracture propagates once the stress intensity factor exceeds a critical value, called fracture toughness. In the second approach, the fracture propagates once the tensile stress ahead of the fracture tip exceeds a critical value, called tensile strength. The purpose of this study is to examine the relation between the two approaches and to determine a methodology to make them equivalent. To address the goal, propagation of a radially symmetric fracture is first analyzed. A universal relation between the tensile strength and fracture toughness is obtained, which is then verified via a series of numerical examples. It is found that in order to capture the fracture toughness the tensile strength should be varied with respect to the mesh size and other material parameters. The developments are then applied to a three-dimensional distinct element code, which can be used in various applications involving modeling of a jointed and blocky material. An additional challenge with the distinct element code lies in the fact that the use of uniform value of tensile strength does not lead to a spatially uniform apparent fracture toughness. The latter is caused by mesh distortions and orientation of the elements relative to the fracture front. This problem is successfully addressed by introducing a variation of the tensile strength relative to local geometry of the mesh in the vicinity of the fracture front. The obtained result develop a procedure to accurately model fracture toughness in numerical methods that use tensile strength as a fracture propagation criterion.

The method of potentiostatic anodic-cathodic chronoamperometry of atomic hydrogen injection into a metal film and its subsequent extraction is theoretically discussed. By combining the methods for studying the phase-structure state and surface morphology with multicycle cathodic-anodic chronoamperometry, the injection (and subsequent extraction) of atomic hydrogen into a 47Pd53Cu (at %) film synthesized by ion-plasma spraying is studied. It is found that the initial stage of hydrogenation proceeds under the mixed diffusion-phase-boundary control and passes to the purely diffusion control in 3–4 s. The main kinetic parameters of the stages of phase-boundary hydrogen penetration and its solid-phase diffusion are found. It is shown that the mass transfer in the film alloy proceeds mainly through the grain bodies rather than along intergrain boundaries. The increase in the β-phase content in the alloy leads to the noticeable increase in the diffusion coefficient of hydrogen, whereas the effective equilibrium constant of the phase-boundary process decreases.

Shales are known to have a finely layered structure, which greatly influences the overall material’s response. Incorporating the effect of all these layers explicitly in a hydraulic fracture simulator would require a prohibitively fine mesh. To avoid such a scenario, a suitable homogenization, which would represent the effect of multiple layers in an average sense, should be performed. We consider a sample variation of elastic properties and minimum horizontal stress versus depth that has more than a hundred layers. We evaluate methodologies to homogenize the stress and the elastic properties. The elastic response of a layered material is found to be equivalent to that of a transversely isotropic material, and the explicit relations for the effective parameters are obtained. To illustrate the relevance of the homogenization procedure for hydraulic fracturing, the propagation of a plane strain hydraulic fracture in a finely layered shale is studied. To reduce the complexity of the numerical model, elastic layering is neglected and only the effect of the stress layers is analyzed. The results demonstrate the ability of the homogenized stress model to accurately capture the hydraulic fracture behavior using a relatively coarse mesh. This result is obtained by using a special asymptotic solution at the tip element that accounts for the local stress variation near the tip, which effectively treats the material at the tip element as nonhomogenized.

We have studied phase transformations of a 20-μm-thick rolled foil of the Pd–57 at % Cu solid solution in a heating–cooling cycle. The as-prepared foil was two-phase, with a nanocrystalline structure. The mutual orientation of the α- and β-phases corresponded to the Nishiyama–Wassermann orientation relationship. Using X-ray diffraction and resistivity measurements, the β ⇆ α phase transformations were shown to be reversible. The effect of the severely deformed initial structure shows up as a shift in the onset temperature and end point of the α → β phase transformation.

The purpose of the investigation carried out is the study of regularities in structural-phase changes and mechanical-chemical processes occurred in a surface layer under the influence of outer and inner technological factors. As experimental equipment there was used a vibration horizontal plant of UVG4x10 type. Working environment consisted of porcelain balls of 4mm diameter, PU-20 zinc powder and an aqueous solution of zinc chloride, and as abrasives – steel plates of 10x10 mm. As a result of the investigations there was determined a mechanism of coating formation, technological regulations for its application were established, surface morphology was investigated. The coating obtained exceeds the electrolytic one by a factor of 1.5 on corrosion resistance due to the absence of a hydrogenated layer.

Thin samples (about 4 μm in thickness) of membrane foil of a Pd–Cu solid solution have been grown on the surface of a SiO2/Si heterostructure by magnetron sputtering. The key features of \(\beta \rightleftharpoons \alpha \) phase transformations have been identified using X-ray diffraction, Auger electron spectroscopy, energy dispersive X-ray microanalysis, and resistivity measurements during a heating–cooling cycle. The results demonstrate that the phase transformations are reversible only in solid solutions containing an excess of copper in the concentration range corresponding to limiting temperatures near the temperature stability limit of the β-phase. Thermal conditions of membrane element operation have been found that ensure stability of the ordered atomic structure of the foil and, accordingly, its high performance. The \(\beta \rightleftharpoons \alpha \) phase transformation has been shown to be reversible after holding the foil at t = 830°C, in a state with a disordered atomic structure, which ensures restoration of its high hydrogen permeability after diffusion bonding to the case of a membrane element.

The goal of this paper is to develop an approximate solution for a propagating plane strain hydraulic fracture, whose behavior is determined by a combined interplay of fluid viscosity, fracture toughness, and fluid leak-off. The approximation is constructed by assuming that the fracture behavior is primarily determined by the three-process (viscosity, toughness, and leak-off) multiscale tip asymptotics and the global fluid volume balance. First, the limiting regimes of propagation of the solution are considered, that can be reduced to an explicit form. Thereafter, applicability regions of the limiting solutions are investigated and transitions from one limiting solution to another are analyzed. To quantify the error of the constructed approximate solution, its predictions are compared to a reference numerical solution. Results indicate that the approximation is able to predict hydraulic fracture parameters for all limiting and transition regimes with an error of under one percent. Consequently, this development can be used to obtain a rapid solution for a plane strain hydraulic fracture with leak-off, which can be used for quick estimations of fracture geometry or as a reference solution to evaluate accuracy of more advanced hydraulic fracture simulators.

Tribomechanical properties of antifriction composites based on the extrudable matrix “UHMWPE + 17 wt. % HDPE-g-VTMS + 12 wt. % PP” with chopped fiberglass formed by three methods: Hot Pressing of Powders (HPP), Hot Pressing of Granules (HPG) and Fused Deposition Modeling (FDM) was studied. It has been found that a composite fabricated by the FDM method possesses the highest strength properties (elastic modulus, yield strength and tensile strength). It is shown that tribological properties (friction coefficient, volumetric wear) of composites fabricated by the three methods are close to each other that is related to impact of the reinforcing filler (fiberglass). The latter takes on compressive and shearing loads during tribo-loading and improves wear resistance of the composite. The studied multicomponent UHMWPE based composite is recommended for use as a feedstock for the manufacturing antifriction products by additive manufacturing.

In this study, a structural and functional analysis was conducted to investigate antifriction multicomponent polymer composites on the basis of ultrahigh-molecular polyethylene (UHMWPE) developed as feedstocks for additive manufacturing of friction parts operating under extreme conditions. The aim was to make UHMWPE extrudable by selecting appropriate polymer plasticizers. An algorithm is proposed for the development of extrudable UHMWPE-based composites with a minimum amount of experimental data available. The algorithm determines the control parameters that provide required characteristics of multicomponent polymer materials and thereby ensure the achievement of desired tribological, mechanical and processing properties. The dependence of the experimentally determined characteristics versus the control parameter values is analyzed, and corresponding response surfaces are constructed in the state space. The surfaces reveal the range of the control parameter values that ensure the achievement of specified properties. The algorithm is applied to select an optimal composition of the ternary “UHMWPE+ 17 wt% HDPE-g-SMA + 12 wt% PP” mixture, whose tribological and mechanical behavior is similar to that of unfilled UHMWPE, but the melt flow is good enough for 3D printing. A comparative study is carried out on structural, mechanical and tribological properties of the multicomponent “UHMWPE+ 17 wt%HDPE-g-SMA+ 12 wt% PP” composites fabricated by FDM printing and hot pressing. It is shown that the tribological and mechanical properties of 3D-printed extrudable UHMWPE-based composites exceed the properties of composites obtained by compression sintering, which is due to the formation of more homogeneous permolecular structure with increased crystallinity. The tribological characteristics of the 3D-printed composites are studied under various friction test conditions (P*V). The composites are proposed as suitable for friction parts operating in a wide range of speeds and loads.

The study results of the zinc coating obtained on the surface of metals in the process of mechanochemical synthesis, implemented in the conditions of vibrowave systems, are presented. The features of coating formation mechanism, an activating role in its formation of free-moving, under the influence of low-frequency vibrations, indenters, are disclosed. The advantages of applying zinc coatings method in comparison with traditional methods are shown.

The article presents materials on the study of mathematical modeling of splicing (binding) of steel rope used to transmit traction by friction. The developed mathematical model splicing (binding) describes the stress-strain state of strands (wires) from quasistatic loads, arising in the cyclic tension process and bending of steel rope on rope sheave, in which the resultant force in steel rope cross section is shifted relative to the central axis, causing it to bend and torsion. Using experimental data, it was found that the steel rope torsion and bending is caused by the linking technology in the nodes where strands are replaced. Experimentally established, that defects on the splicing (binding) site manifested as a result of cyclic tensile and bending loads on rope sheave, which is connected to limited mobility of the strands in nodes due to cross section symmetry violation.

A novel device is presented which is designed for in-process measurements of the variation of the diameter of highly reflective spheres. Silicon spheres have been used for the new definition of the International System of Units (SI). Many spheres have to be processed, and the form of these objects, and thus the manufacturing process’s stability, needs to be controlled every day. Commercially available measurement equipment and even state-of-the-art spherical interferometers have reached their limits in terms of resolution, uncertainty, the complexity of their handling routines, measurement time and even financial investment. A novel setup has thus been designed after considering and selecting a special mechanical setup with a minimal measurement loop, stable optical sensors and a handling strategy which avoids collision and contact with the very valuable, superpolished spherical objects. Thus, the design minimizes the influence of the environment and reduces the measurement time at an equator with sub-nanometre resolution to 3 min. In addition, the analysis time is reduced to less than a minute.