bluuebunny/crossref_metadata_2025 huggingface dataset:
The effect of curing temperature on phase separation, morphology, fracture toughness and impact resistance of epoxy-polysulfone blends and fiber reinforced plastics based on them
Authors: Solodilov V I , Shapagin A V , Korokhin R A , Gorbatkina Yu A
Published: December 2019

The influence of the curing temperature of epoxy - polysulfone compositions on crack and impact resistance of matrices and unidirectional reinforced plastics was studied. It was shown that the structure of cured material depends on the content of PSK-1 and the curing temperature. Stable effect of increasing fracture toughness, as a rule, is observed for matrices with an extended structure of thermoplastic, which is typical for the phase structures of the type "interpenetrating phases". Energy of destruction of fiber reinforced plastics is determined by the fracture toughness of the matrix and its resistance to impact, which depend on the type of structure formed in the curing process.
Increase of composite structures strength by carbon fiber surface modification with spray deposited carbon nanotubes
Authors: Levin D D , Romashkin A V , Polikarpov Yu A , Struchkov N S , Kireynov A V , Komarov I A
Published: December 2019

The possibility of carbon fiber and the polymer matrix interfacial interface improvement by modification carbon fiber surface with functionalized carbon nanotubes. Nanotubes were deposited to carbon fiber surface by aerosol spray deposition, to increase the tensile strength of composite structures. The relationship between the tensile strength of the composite structure with the epoxy matrix and the uniformity of carbon nanotube coating was investigated.
Fabrication of samples and study on mechanical properties of metal matrix composites with system “Al-nanoAl2O3”
Authors: Chen Y , Kurganova Yu A , Shcherbakov S P , Gaaze V K
Published: December 2019

Experimental samples of aluminum matrix composite materials filled with discrete Al2O3 fibers with a diameter of 10–20 nm were obtained by liquid-phase mechanical mixing. Copper powder with a diameter of 10 μm used as a transport component for the introduction of a light nanosized fraction. A comparative analysis of the hardness and microhardness of the experimental samples demonstrated the presence of a modifying effect from the introduction of discrete Al2O3 fibers.
Studying the Structure of Products Made of Titanium Carbide Hardened by the Impregnation Method
Authors: Kulikov V Yu , Kvon Sv S
Published: December 2019

The paper presents the results of studying the structure of products made of titanium carbide hardened by the impregnation method. As a bonding alloy a high-temperature alloy of the Fe-Cr-Ni-Co system was used. Samples of different porosity were impregnated with that alloy, then their structure was investigated by the methods of mercury porosimetry and electron microscopy. The data of the parameters of porosity and some mechanical properties are given. It was found that there is a correlation between the average size of open pores and the tensile strength and the ultimate strength limit. It is shown that this relationship is logical if to consider the resulting structure as a composite material: the matrix of titanium carbide which pores are filled with a metal bond. It is shown at what parameters of the porous structure the impregnation process proceeds most fully.
Multiscale modeling of deformation and damage of elasticplastic particle reinforced composites
Authors: Dimitrienko Yu I , Yurin Yu V , Sborschikov S V
Published: December 2019

A model is proposed for the deformation of elastic-plastic particle reinforced composite materials of a periodic structure with allowance for the damage. The model is based on a variant of the deformation theory of plasticity under active loading, in which the damage parameter is introduced, taking into account the difference in the accumulation of damage in phases during shear, tension and compression. The method of asymptotic homogenization of periodic structures was used to model the effective characteristics of elastic-plastic composites. Examples of numerical calculation are carried out for particle-reinforced metal composite - aluminum matrix filled with SiC particles.
Structure and properties of the composite material based on heat-resisting VKNA-4U alloy with oxide stiffening fillers, designed for additive manufacturing technologies of power fasteners for gas turbine engines (GTE)
Authors: Unchikova M V , Rodionov A I , Golovlev N A
Published: December 2019

The influence of the structure and concentration of the stiffening component on the physicomechanical properties of the heat-resisting intermetallic alloy VKNA-4U was investigated. The dependence of the strength properties of the alloy on the composition and ratio of the hardeners α-Al2O3, Y2O3, HfO2, ZrO2 was experimentally determined. Using scanning electron microscopy (SEM), it was found that when the alloy is reinforced with hafnium, yttrium and aluminum oxides, the dispersed hardener does not dissolve in the matrix. These compositions are considered as the most promising for the stiffening of VKNA-4U alloy.

It is shown in this paper that the required content of the oxide reinforcing filler in the VKNA-4U matrix is 2%, at which a balance is reached between the maximum value of strength and ductility. In the future, VKNA-4U powder composition mechanically alloyed with β-Al2O3, Y2O3, HfO2 oxides can be used as a building material for additive synthesis technologies for power fasteners of gas turbine engines (GTE).
Mapping hole mobility in PTB7 films at nanoscale
Authors: Alekseev A M , Yedrissov A T , Ilyassov B R , Hedley G J , Samuel I D W , Kharintsev S S
Published: December 2019

The nanoscale hole mobility in organic semiconducting polymer PTB7 is quantified by using conductive-AFM (C-AFM) measurements in space charge limited (SCLC) regime. The obtained current map of the neat PTB7 film is explained in terms of non-uniform built-in voltage and variations of hole mobility. For mobility estimation, the semi-empirical model of SCLC, known from previous works, was modified and applied. It is found that the values of built-in voltage in C-AFM measurements are usually several times larger than ones derived from macroscopic measurements. It is also shown that value of hole mobility in PTB7 film depends on location and varies in more than two times. These mobility variations are connected with nanoscale film structure revealed by other methods.
Phase composition investigation of titanium oxide nanostructures obtained by the local anodic oxidation
Authors: Avilov V I , Smirnov V A , Tominov R V , Sharapov N A , Polupanov N A , Ageev O A
Published: December 2019

The paper presents the results of a phase composition study of titanium oxide nanostructures obtained by local anodic oxidation. A mathematical model was presented, which made it possible to calculate the distribution of oxide phases in the nanostructure volume. The results of the X-ray photoelectron spectroscopy (XPS) spectrum analysis are presented, which are consistent with theoretical calculations.
Investigation of resistive switching by non-stationary signals in ZrO2(Y) films by atomic force microscopy
Authors: Filatov D O , Koriazhkina M N , Antonov D A , Antonov I N , Liskin D A , Ryabova M A , Gorshkov O N
Published: December 2019

Resistive switching in the yttria stabilized zirconia films on the conductive substrates has been studied using Conductive Atomic Force Microscopy. Switching was performed by triangle voltage pulses with superimposed high-frequency sinusoidal signal applied between the probe and the sample. The performance of the resistive switching was characterized quantitatively by the ratio of the electric current flowing through the contact of the probe to the dielectric film surface (together constituting a nanometre-sized virtual memristor) in the low resistance state and in the high resistance one (ON/OFF ratio). The increase in this ratio when applying the sinusoidal signal as compared to the switching by the triangle pulses has been observed. Also, the long-time scale stability of the mean values of the probe current in both states was found to improve when applying the sinusoidal signal. The effect of the high frequency sinusoidal signal on the performance of the virtual memristor was attributed to the resonant activation of the oxygen ion migration via the oxygen vacancies by the alternating external electric field.
Creation of thin superconducting MoCN thin film by cathode sputtering technique as a basic material for functional cryogenic nanoelements
Authors: Goncharov B V , Gurovich B A , Dementyeva M M , Prikhodko K E , Olshansky E D , Kutuzov L V
Published: December 2019

Thin MoCN films were synthesized by a method of cathode sputtering of mosaic Mo-C targets by nitrogen ions at temperature of 800°C on substrates of the oxidized silicon. The temperature dependences of electrical resistance of the films in the range of 4.2–300°K were measured. Volt-ampere characteristics of the films and critical current density vs film thickness were obtained at a temperature of 4.2°K. The microstructure and film-depth chemical composition profiles of thin films were investigated by analytical techniques of the transmission electron microscopy (HRTEM, EELS) on a cross-section samples made by the focused ion beam (FIB). It was established that MoCN thin film at a thickness of 8 nm contained MoC and Mo5N6 layers. The high density of critical current in these films indicated prospects of their application in the field of cryogenic nanotechnologies.
Integrated cryogenic resistors formed from NbN thin film under ion beam irradiation
Authors: Gurovich B A , Goncharov B V , Dementyeva M M , Prikhodko K E , Kutuzov L V , Komarov D A , Domantovsky A G
Published: December 2019

Niobium nitride ultrathin films were synthesized by cathode sputtering technique. The cryogenic resistors built in the superconducting nanowire were formed using the radiation technology developed in National Research Centre “Kurchatov Institute”. This technique was based on the transformation of NbN superconducting film to a normal state (at 4.2K) under the composite ion beam irradiation through the resistive mask. The formation of the cryogenic resistors in the broad range of values was demonstrated.
Dependence of pyroelectric response on inter-electrode capacitance for integrated-optical circuits utilizing x-cut LiNbO3 chips
Authors: Kostritskii S M , Yatsenko A V , Korkishko Yu N , Fedorov V A
Published: December 2019

Experimental study of the pyroelectric effect has been made for multi-function integrated-optical circuits (MIOC) utilizing x-cut LiNbO3 chips. It has been experimentally established that pyroelectric voltage is proportional to the temperature scanning rate, and a voltage magnitude depends significantly on capacitances of chip parts between the MIOC electrodes. The pyroelectric effect is considered by us to be an important source of the thermal instability of MIOC. The model of the pyroelectric contribution to the MIOC thermal instability is used to suggest the new methods reducing this instability.
Kinetics of photo-stimulated adsorption of enzyme molecules onto n- and p-type silicon
Authors: Kozlowski A V , Stetsyura S V
Published: December 2019

We report on a change in the surface density of glucose oxidase (GOx) molecules on surface of Si/SiO2/polyethyleneimine structures depending on type of Si conductivity, adsorption time and white-light illumination of a substrate during GOx adsorption. It is clearly shown by AFM images that the dependence of GOx adsorption on adsorption time and illumination is different for n-Si and p-Si substrates. The results can be explained by the electrostatic interaction between GOx molecules and the surface charge of Si, which depends on illumination.
Charge injection into the Ni-phyllosilicate nanoscrolls with reduced Ni nanoparticles using Kelvin force probe microscopy
Authors: Kunkel T S , Krasilin A A , Khrapova E K , Straumal E A , Nomine A , Ghanbaja J , Ankudinov A V
Published: December 2019

The evolution of the electrical charge injected into Ni-doped phyllosilicate nanoscrolls composites deposited on a conductive substrate was studied by Kelvin probe force microscopy. The nanoscrolls were synthesized by hydrothermal method and then annealed in H2/Ar flow at 400-900°C in order to reduce Ni up to metal. A typical agglomerate of the Ni3Si2O5(OH)4 nanoscrolls accumulated the charge on one nanoscroll followed by a subsequent partial destruction of the agglomerate. For the Ni2MgSi2O5(OH)4 nanoscrolls, the whole agglomerate could be charged, and the injected charge was retained for hours. The shortest charge relaxation time was revealed for the nanoscrolls annealed at the highest temperature, when Ni was completely reduced.
In-situ Raman mapping during indentation
Authors: Maslenikov I I , Useinov A S
Published: December 2019

Transparent diamond tip described elsewhere allows combining mechanical indentation measurement with optical methods, including not only surface observation, but also spectroscopy measurements, in particular, Raman spectroscopy. Current work considers the possibilities of creating Raman maps, which give an information about the pressure distribution and ratio of material phases. Corresponding maps are presented for the case of indentation of DLC film on a silicon sample.
Structural-mechanical AFM study of inhomogeneous stiff nanocoating of soft polymer substrate
Authors: Morozov I A , Kamenetskikh A S
Published: December 2019

Modification of polymer with low-energy gas plasma is used to change the wettability of the surface and, as a consequence, to improve the interactions with biological objects. As a result of such treatment, a nanolayer, which is stiffer than the initial surface, is formed on a broad class of polymers. Elastic polyurethane is one of the widely used polymers. This is two-phase material consisting of soft and hard blocks. Its surface was treated by low-energy argon plasma and studied by an atomic force microscopy (AFM): the structure becomes rough and mechanically inhomogeneous depending on the part of the surface treated (hard or soft blocks of the material). The average value of elastic modulus increases with the treatment time, but the average thickness of the coating does not change, having a wide dispersion. All these features are related with the heterogeneous surface peculiarities of the initial polymer.
Microscopy of composite materials based on carbon fibre
Authors: Muravyeva T I , Shcherbakova O O , Shpenev A G , Zagorskiy D L
Published: December 2019

The work is devoted to a composite material consisting of carbon fibres in a carbon pitch-based matrix. Due to its high wear and heat resistance, this material is widely used in aviation brake systems. Two samples with different impregnation of fibres were studied. It is shown that their tribological properties are different. A complex method of microscopy (optical, scanning electron, and scanning probe microscopies) was used to study the friction surface and inner structure of the samples. In the sample with the best properties, the fibres have a regular ribbed side surface, fibre bundles are located parallel to the friction surface, matrix around the fibres has a denser structure. It is also shown that in this sample wear rates of the fibres and the matrix are the same. Thus, a small change in the production process leads to a noticeable change in the structure, which determines the operational properties.
Optimization of the photonic crystal colloidal films deposition by means of atomic force microscopy
Authors: Panfilova E V , Syritskii A B , Ibragimov A R
Published: December 2019

This article describes the results of optimization of the colloidal photonic crystal opal films deposition by means of atomic force microscopy investigation. The main factors affecting the quality of the colloidal opal films are studied. Bragg diffraction occurs in the periodic distribution of colloidal microspherical particles, and ordered structure is critical for formation of the photonic band gap. It is found that polystyrene opal structures obtained in optimal conditions have a good periodicity, uniformity, and high packing density.
Morphological and kinetic consequences of scratching of the growing crystal surface
Authors: Piskunova N N
Published: December 2019

Using the atomic-force microscopy (AFM) it is shown that even a minor local contact of an AFM probe with a growing crystal surface at the nanoscale leads to important crystallogenetic (morphological and kinetic) consequences. These non-linear effects are the thickening of steps, the huge fluctuations, and a loss of morphological stability of the surface even at the distance of dozens of micrometres from the contact area. Near the equilibrium state, we observed the phenomenon of simultaneous growth and dissolution at the neighbouring points of one step.
Determination of rate of epitaxial growth by means of combined usage of atomic force microscopy and light scattering data
Authors: Rassadin A E
Published: December 2019

In the paper, a method of experimental estimation of epitaxial growth rate has been suggested. A corner stone of this method is obtaining image of initial shape of solid state surface by means of atomic force microscopy before the start of the process of epitaxial growth. These experimental data should be completed by measurements of special bistatic cross-section of visible light scattering on the sample surface both before the beginning of technological process and after its end. Mathematical model of epitaxial growth is based on simplification of the Kardar-Parisi-Zhang equation. The method of characteristics has been applied to solve this equation.
Heterogeneous ferromagnetic state in small particles and its connection with ferroelectricity
Authors: Shaposhnikova T S , Mamin R F
Published: December 2019

PTs in spherical particles of a cubic ferromagnetic was considered in the framework of the Ginzburg-Landau phenomenological theory. Concentrating on depolarizing field effects, we study the competition between states with homogeneous magnetization and vortex structures. For large sphere radii (R>Rc), a PT to a vortex state is possible, while for R<Rc it can be a homogeneous state. We obtain the inhomogeneous distribution of the ferromagnetic order parameter in the form of 2D and 3D vortices, for which the absolute value of the local magnetization depends on the distance from the centre of the vortex. This approach can be used for nano-sized particles. In our work, we compute the polarization caused by ferromagnetic 2D and 3D vortices within the phenomenological approach.
Tip-induced domain growth in the non-polar cuts of SBN:Ce single crystals
Authors: Shikhova V A , Neradovskaia E A , Turygin A P , Fedorovyh V V , Anikin V A , Ivleva L I , Ya Shur V
Published: December 2019

The local switching by conductive tip of scanning probe microscope was studied in the non-polar cuts of Ce-doped Sr0.61Ba0.39Nb2O6 single crystals after creation of the single-domain state. The switched domains possessed the egg-shaped heads and wedge-like tails. The dependences of lengths of the domain head and tail and width of the domain head on the voltage and pulse duration were derived. The start voltage for growth of the domain tail was revealed. The fast relaxation of the domain head and slow relaxation of the domain tail were observed. The model of the forward domain growth by step generation and kink motion was used for explanation of the experimental results. The obtained knowledge can be used for the domain engineering in ferroelectrics.
Creation of nanoparticles and surface nanostructures of alumina by hot water treatment
Authors: Shur V Ya , Mingaliev E A , Makaev A V , Chezganov D S , Kozheletova I Y , Pryakhina V I
Published: December 2019

In this report, we present a detailed study of the formation of alumina nanostructures at the surface of aluminium plate by hot water treatment (HWT) at various temperatures. The nanostructures were studied by scanning electron microscopy. The superhydrophilic property of the treated surface was revealed and its stability was investigated. It was shown that HWT could be used also for synthesis of the aqueous suspensions of alumina nanoparticles. It is proposed that the method can be applied for production of surface nanostructures and nanoparticles of various metal oxides.
Organism’s responses to a long-term inhalation of silica-containing submicron particles of an industrial aerosol
Authors: Solovyeva S N , Katsnelson B A , Sutunkova M P , Privalova L I , Gurvich V B , Minigalieva I A , Slyshkina T V , Valamina I E , Shur V Ya , Zubarev I V , Kuznetsov D K
Published: December 2019

Female white rats were exposed during up to 6 months 5 times a week, 4 hr per day in a “nose only” inhalation device to an aerosol containing predominantly submicron (nanoscale included) particles of amorphous silica in the concentration 2.6±0.6 or 10.6±2.1 mg/m3. In an auxiliary experiment with a single-shot intratracheal instillation of these particles, it was shown that they induced a pulmonary cell response comparable with that to highly cytotoxic and fibrogenic standard quartz powder DQ12. However, in the long-term inhalation test, the studied aerosol proved to be of very low systemic toxicity and fibrogenicity. This paradox may be explained by low SiO2 retention in lungs and other organs due to a relatively high in vivo solubility of these nanoparticles. Nevertheless, their genotoxic action and transnasal penetration into the brain should make one give a cautious overall assessment of this aerosol as an occupational or environmental hazard.
PFM studies of ferroelectric phase transition in superprotonic (K0.43(NH4)0.57)3H(SO4))2 crystals
Authors: Tolstikhina A L , Gainutdinov R V , Selezneva E V , Makarova I P
Published: December 2019

The new superprotonic crystal (K0.43(NH4)0.57)3H(SO4))2 is investigated by the scanning probe microscopy and X-ray diffraction. It is shown by piezoresponse force microscopy (PFM) that the crystal is in paraelectric phase at room temperature. The ferroelectric phase transition in the crystal at the temperature decreasing from 296 to 282 K is revealed by PFM. The thin nanorelief is observed at the natural cleavage surface of the crystals by studying its topology with atomic force microscopy. The pits and hills of the nanorelief demonstrate the stable depth (height) of about 0.7 nm, which corresponds to 1/3 unit cell in c axis direction.
Fabrication of superhydrophobic and superoleophilic teflon surfaces using irradiation by nanosecond infrared laser
Authors: Volchetskaya K V , Kuznetsov D K , Ya Shur V
Published: December 2019

Polytetrafluoroethylene (PTFE, teflon) possesses excellent stability and low surface energy, which enables its extensive use in the manufacture of biomimetic superhydrophobic surfaces. We proposed a simple and fast method for producing superhydrophobic surfaces by treating the teflon plate by nanosecond pulse infrared irradiation by means of CO2 laser. The surface relief was visualized by scanning electron microscope. The surface wettability was estimated by measuring the contact angle. The treated teflon superhydrophobic surfaces with static contact angle up to 154°demonstrated self-cleaning properties. The creation of regular two-dimensional structures leading to super-adhesive property of the teflon surface was shown. Thus, it was shown that the surface treating of teflon by nanosecond infrared laser could be used for creation of the super-hydrophobic surfaces for various applications such as self-cleaning, microfluidic devices, and the laboratory-on-chip systems.
Nonlinear viscoelastic properties of nanosuspensions
Authors: Dembelova T S , Badmaev B B , Makarova D N , Vershinina Ye D
Published: December 2019

This paper studies the dependence of the shear elasticity modulus and the coefficient of dynamic viscosity of the suspensions on the magnitude of the shear strain of nanoparticle suspensions in a polymer liquid. As the dispersion medium, polyethylsiloxane liquid PES-2 was used, the solid dispersed phase - silica nanoparticles and fullerenes. We used the acoustic resonance method for determining the complex shear modulus of liquids using a piezoquartz resonator. Studies have shown nonlinear behavior of viscoelastic parameters of suspension samples depending on shear stress.
The temperature coefficient delay time of the Rayleigh waves
Authors: Simakov I G , Gulgenov Ch Zh , Bazarova S B
Published: December 2019

The effect of variation of temperature of adsorbing surface and humidity of gas medium on velocity of surface acoustic waves in layered system "adsorbed water - lithium niobate" has been investigated. The dependence of temperature coefficient delay time of the Rayleigh waves in system "adsorbed water - lithium niobate" on degree of moisture content of gas medium was considered.
Periodic temperature field in a composite plate
Authors: Abiduev P L , Darmaev T G , Buldaev A S
Published: December 2019

The temperature fields in two-layer plates under periodic temperature effects on one of the surfaces are considered. The transition to a steady-state temperature field is investigated. For numerical calculations, a program based on the implementation of the finite element method was used. The same steady-state periodic temperature field was obtained asymptotically and was compared with the results of a numerical experiment. Numerical tests showed that for loads close to explosion during detonation of gas mixtures in thermodynamic treatment measures, the periodic temperature field is established after 5-6 cycles of heat flow exposure. Also after analysis of temperature field in single-layer and double-layer plates it is shown that introduction of thermal protection allows to significantly lower temperature of surface under influence of heat flow.
Magnesium thermal nano-sized powders of the chromium subgroup metals
Authors: Kolosov V N , Orlov V M , Miroshnichenko M N , Prokhorova T Yu
Published: December 2019

A method for magnesium vapor reduction of the double oxides of chromium subgroup metals at low static pressure and dynamical vacuum was used. The study results of the production and investigation of tungsten, molybdenum, chromium, W-Cr mix and Mo-W alloy powders are presented. The specific surface area of the resulting powders was in the range from 14 to 41 m2·g−1. The average crystalline grain size estimated from the value of the range of coherent X-ray scattering was 8-40 nm.
A method to determine uranium compounds in drinking water
Authors: Tegshbayar N , Tsookhuu Kh , Bolormaa O
Published: December 2019

In this paper we have studied the possibility of determining the forms of uranium ions and minerals dissolved in water by using the Pourbaix diagram. Uranium in water with low uranium content exists in the form of uraninite or uranium dioxide UO2+ and with higher uranium content in the form of ions UO2(CO3). By selecting carbonate minerals and calculating the saturation index, it is shown that uranium in the water of Eastern region of Mongolia dissolved in the forms of minerals such as quartzite CaMgUO2(CO3)3(H2O)12, andersonite (Na2CaUO2(CO3)3(H2O)6), bayleyite (Mg2UO2(CO3)3(H2O)18), liebigite (Ca2UO2(CO3)3(H2O)10).
Assessment of optical, mechanical and nonlinear properties of potassium acid phthalate single crystal: a potential candidate for optoelectronic applications
Authors: Kumari Manju , Vijayan N , Nayak Debabrata , Kumar Mahesh , Gupta Govind , Pant R P
Published: December 2019

A good optical quality semi-organic single crystal of Potassium Acid Phthalate (KAP) was harvested from aqueous solution by using slow evaporation solution growth technique (SEST) at ambient condition. The defect free single crystal of KAP was analyzed by different instrumentation techniques, for checking its compatibility for different applications. Its unit cell dimensions and phase purity was examined by powder X-ray diffraction (PXRD) and found that it crystallizes in orthorhombic with non-centrosymmetric in nature. The quality of the grown ingot was assessed by high resolution X-ray diffraction (HRXRD) technique and found that, the crystalline quality is better with less grain boundaries. Its optical properties were scrutinized by UV–vis., photoluminescence (PL) and time resolved photoluminescence (TRPL) measurements respectively. The mechanical stability of the grown crystal was tested by Vickers microhardness method and found that the grown crystal shows indentation size effect (ISE) which was explained using different theoretical models. Its third order nonlinear optical properties were studied by Z-scan measurement by using Ti:Sapphire laser as a source and determined its nonlinear absorption coefficient (β) and it was found that the KAP crystal is one of the preferable choices for optical limiting applications.
Synthesis of PLA-based thermoplastic elastomer and study on preparation and properties of PLA-based shape memory polymers
Authors: Ji Fan , Li Jianbo , Weng Yunxuan , Ren Jie
Published: December 2019

As a new functional polymer material, shape memory polymer (SMP) has many advantages, and can be widely used in medical devices, textiles, aerospace and other fields. For thermal response SMPs, temporary deformation can be stored under external force above Tg with a rapid cooling down to below Tg or Tm, and when heated again to the critical temperature point, they return to their original shape. In this paper, shape memory poly (lactic acid) (PLA) block copolymers were prepared from a chain extension reaction of PLA with poly(ε-caprolactone) diol (PCL-OH). Using hexamethylene diisocyanate (HDI) as a chain extender, the molecular weight of the prepolymer could be greatly increased by melt chain extension. Polylactic acid thermoplastic elastomer (PLAE) synthesized by chain extension reaction is soft and tough, similar to thermoplastic polyurethane (TPU). Polylactic acid-based shape memory polymers with good shape memory properties can be obtained by blending PLAE with PLA. The shape memory property test showed that the polylactic acid-based shape memory polymer was successfully prepared, and the recovery rate of the polylactic acid-based shape memory polymer could reach to approximately 80%. Besides, we also did thermal and microstructural analysis of the blend material. Due to their good biocompatibility and biodegradability, PLAE and PLA/PLAE will have potential applications in biomedical implant materials, engineering plastics, and textiles.
Oxygen annealing effect on resistive switching characteristics of multilayer CeO2/Al/CeO2 resistive random-access memory
Authors: Ismail Muhammad , Khan Sobia Ali , Rahmani Mehr Khalid , Choi Junhyeok , Batool Zahida , Rana Anwar Manzoor , Kim Sungjun
Published: December 2019

Cerium oxide-based memristors have been extensively studied because of their compatibility with CMOS technology. Yet, inconsistency of resistive switching parameters is one of the main contests in development of nonvolatile memory for commercialization. Owing to filamentary nature of the resistive switching devices, variability of the resistive switching characteristics can be reduced by doping, where conductive filaments can easily grow due to reduction in the formation energy of oxygen vacancies. In this work, multilayer CeO2/Al/CeO2 films were prepared through radio-frequency (rf) sputtering at room temperature to study the effect of oxygen annealing on the resistive switching characteristics. Device with CeO2/Al/CeO2 multilayer structure after annealing exhibits reduction of defects and improved switching endurance, good data retention, and uniformity in operational parameters. The resistive switching characteristics have been simulated using space charge limited conduction and Schottky emission at high field region of the high resistance state, which is well fitted by linear curve fitting analysis. Improvement in the switching characteristics revealed that Al charge trapping layer has diffused into the CeO2 matrix, which might have resulted in lower density of oxygen vacancies due to oxygen annealing. Experimental I–V analysis indicate that oxygen annealing is an effective approach to enhance the switching characteristics of RRAM devices.
Erosion behaviour of boiler component materials at room temperature and 400 °C temperature
Authors: Singh Prashant Kumar , Mishra S B
Published: December 2019

Degradation of boiler tube components in Indian thermal power plants is mainly done through solid particle erosion due to exposure in erosive ash environment. Some important parameter such as hardness, erodent velocity, temperature, impact angle, shape and size are majorly affected the erosion wear. In this study, the erosion wear behaviour of SAE 208 grade steel, SAE213-T12 boiler steel, SAE213-T91 boiler steel and IS 2062 structural steel were investigated using an air jet erosion test rig. The erosion tests were carried out at the impact angles of 30° and 90°, impact velocity of 42.3 m/s at room temperature and 400 °C. The position of sample holder was adjusted in such a way that erosion wear scar occur at the central region of the samples. For each experiment, the erosion test was continued until the steady state erosion rate was achieved as per ASTM standard. The variation in erosion rate data has been plotted against cumulative mass of erodent for boiler and structural steel samples. The steady state erosion rates for different steel samples are calculated and compared. The surfaces of tested samples are analyzed using scanning electron microscopy to understand the erosion mechanism. The results showed that the ductile behaviour of erosion mechanism is dominated at both room temperature and 400 °C temperature. Mechanism involved at 90° impact angle is plastic deformation with formation of craters and at 30° impact angle is cutting and ploughing.
US Migration Status of Adult Children and Cognitive Decline Among Older Parents Who Remain in Mexico
Authors: Torres Jacqueline M , Sofrygin Oleg , Rudolph Kara E , Haan Mary N , Wong Rebeca , Glymour M Maria
Published: December 2019

Low- and middle-income countries (LMICs) are experiencing rapid aging, a growing dementia burden, and relatively high rates of out-migration among working-age adults. Family member migration status may be a unique societal determinant of cognitive aging in LMIC settings. We aimed to evaluate the association between adult child US migration status and change in cognitive performance scores using data from the Mexican Health and Aging Study, a population-based, national-level cohort study of Mexico adults aged ≥50 years at baseline (2001), with 2-, 12-, and 14-year follow-up waves (2003, 2012, and 2015). Cognitive performance assessments were completed by 5,972 and 4,939 respondents at 11 years and 14 years of follow-up, respectively. For women, having an adult child in the United States was associated with steeper decline in verbal memory scores (e.g., for 9-year change in immediate verbal recall z score, marginal risk difference (RD) = –0.09 (95% confidence interval (CI): −0.16, −0.03); for delayed verbal recall z score, RD = –0.10 (95% CI: −0.17, −0.03)) and overall cognitive performance (for overall cognitive performance z score, RD = –0.04, 95% CI: −0.07, −0.00). There were mostly null associations for men. To our knowledge, this is the first study to have evaluated the association between family member migration status and cognitive decline; future work should be extended to other LMICs facing population aging.
Correlations Between Interleukin-11 Expression and Hypertensive Kidney Injury in a Rat Model of Renovascular Hypertension
Authors: Menendez-Castro Carlos , Cordasic Nada , Dambietz Thomas , Veelken Roland , Amann Kerstin , Hartner Andrea , Hilgers Karl F
Published: December 2019

BACKGROUND

Interleukin-11 (IL-11) is a pleiotropic cytokine of the interleukin-6 family. Recent studies revealed its crucial role in the development of cardiovascular fibrosis. In this study we examined IL-11 expression levels in the heart and the kidney exposed to high blood pressure in renovascular hypertensive rats and their correlations to fibrotic markers and kidney injury.

METHODS

Two-kidney, one-clip renovascular hypertension (2K1C) was induced in rats. IL-11 expression was measured by real-time polymerase chain reaction in the left ventricle and the right kidney. The correlation of cardiac IL-11 expression with biomarkers of renal fibrosis was assessed. We further investigated IL-11 expression in 2K1C rats grouped into rats with malignant vs. nonmalignant hypertension (distinguishing criteria: weight loss, number of fibrinoid necrosis, and onion skin lesions).

RESULTS

Thirty-five days after clipping, mean arterial pressure was significantly increased in 2K1C. Renal IL-11 expression was elevated in 2K1C. In the heart there was only a trend toward higher IL-11 expression in 2K1C. IL-11 in the kidney in 2K1C correlated with the expression of transforming growth factor (TGF)-β1/2, collagens, fibronectin, osteopontin, as well as tissue inhibitors of metalloprotease 1/2. There were also correlations of IL-11 with tissue collagen expansion, number of activated fibroblasts and serum creatinine, but no correlation with mean arterial pressure. Renal expression of IL-11 was highest in rats with malignant hypertension.

CONCLUSIONS

Renal IL-11 expression of renovascular hypertensive rats is markedly increased and correlates with profibrotic markers and loss of function and might therefore serve as a biomarker for the severity of hypertensive nephrosclerosis.
Extrapolating the Applicability of Measurement Data on Worker Inhalation Exposure to Chemical Substances
Authors: Franken Remy , Shandilya Neeraj , Marquart Hans , McNally Kevin , Fransman Wouter
Published: December 2019

Measured data are generally preferred to modelled estimates of exposure. Grouping and read-across is already widely used and accepted approach in toxicology, but an appropriate approach and guidance on how to use existing exposure measurement data on one substance and work situation for another substance and/or work situation is currently not available. This study presents a framework for an extensive read-across of existing worker inhalable exposure measurement data. This framework enables the calculation of read-across factors based on another substance and/or work situation by first evaluating the quality of the existing measurement data and then mapping its similarity or difference with another substance and/or work situation. The system of read-across factors was largely based on the determinants in ECETOC TRA and ART exposure models. The applicability of the framework and its proof of principle were demonstrated by using five case studies. In these case studies, either the 75th percentiles of measured exposure data was observed to lie within the estimated 90% confidence intervals from the read-across approach or at least with the increase in the geometric mean of measured exposure, geometric mean of estimated exposure also increased. Testing and re-evaluation of the present framework by experts in exposure assessment and statistics is recommended to develop it further into a tool that can be widely used in exposure assessment and regulatory practices.
Female Assamese macaques bias their affiliation to paternal and maternal kin
Authors: De Moor Delphine , Roos Christian , Ostner Julia , Schülke Oliver
Published: December 2019

Forming strong social bonds can lead to higher reproductive success, increased longevity, and/or increased infant survival in several mammal species. Given these adaptive benefits, understanding what determines partner preferences in social bonding is important. Maternal relatedness strongly predicts partner preference across many mammalian taxa. The role of paternal relatedness, however, has received relatively little attention, even though paternal and maternal kin share the same number of genes, and theoretically similar preferences would therefore be expected for paternal kin. Here, we investigate the role of maternal and paternal relatedness in female affiliation in Assamese macaques (Macaca assamensis), a species characterized by a relatively low male reproductive skew. We studied a wild population under natural conditions using extensive behavioral data and relatedness analyses based on pedigree reconstruction. We found stronger affiliative relationships and more time spent grooming between maternal kin and paternal half-sisters compared with nonkin, with no preference of maternal over paternal kin. Paternally related and nonrelated dyads did not form stronger relationships when they had less close maternal kin available, but we would need a bigger sample size to confirm this. As expected given the low reproductive skew, affiliative relationships between paternal half-sisters closer in age were not stronger than between paternal half-sisters with larger age differences, suggesting that the kin bias toward paternal kin was not mediated by age similarity. An alternative way through which paternal kin could get familiarized is mother- and/or father-mediated familiarity.
Disrupted basal ganglia–thalamocortical loops in focal to bilateral tonic-clonic seizures
Authors: He Xiaosong , Chaitanya Ganne , Asma Burcu , Caciagli Lorenzo , Bassett Danielle S , Tracy Joseph I , Sperling Michael R
Published: December 2019

Focal to bilateral tonic-clonic seizures are associated with lower quality of life, higher risk of seizure-related injuries, increased chance of sudden unexpected death, and unfavourable treatment outcomes. Achieving greater understanding of their underlying circuitry offers better opportunity to control these seizures. Towards this goal, we provide a network science perspective of the interactive pathways among basal ganglia, thalamus and cortex, to explore the imprinting of secondary seizure generalization on the mesoscale brain network in temporal lobe epilepsy. Specifically, we parameterized the functional organization of both the thalamocortical network and the basal ganglia–thalamus network with resting state functional MRI in three groups of patients with different focal to bilateral tonic-clonic seizure histories. Using the participation coefficient to describe the pattern of thalamocortical connections among different cortical networks, we showed that, compared to patients with no previous history, those with positive histories of focal to bilateral tonic-clonic seizures, including both remote (none for >1 year) and current (within the past year) histories, presented more uniform distribution patterns of thalamocortical connections in the ipsilateral medial-dorsal thalamic nuclei. As a sign of greater thalamus-mediated cortico-cortical communication, this result comports with greater susceptibility to secondary seizure generalization from the epileptogenic temporal lobe to broader brain networks in these patients. Using interregional integration to characterize the functional interaction between basal ganglia and thalamus, we demonstrated that patients with current history presented increased interaction between putamen and globus pallidus internus, and decreased interaction between the latter and the thalamus, compared to the other two patient groups. Importantly, through a series of ‘disconnection’ simulations, we showed that these changes in interactive profiles of the basal ganglia–thalamus network in the current history group mainly depended upon the direct but not the indirect basal ganglia pathway. It is intuitively plausible that such disruption in the striatum-modulated tonic inhibition of the thalamus from the globus pallidus internus could lead to an under-suppressed thalamus, which in turn may account for their greater vulnerability to secondary seizure generalization. Collectively, these findings suggest that the broken balance between basal ganglia inhibition and thalamus synchronization can inform the presence and effective control of focal to bilateral tonic-clonic seizures. The mechanistic underpinnings we uncover may shed light on the development of new treatment strategies for patients with temporal lobe epilepsy.
Neutralizing and Neuraminidase Antibodies Correlate With Protection Against Influenza During a Late Season A/H3N2 Outbreak Among Unvaccinated Military Recruits
Authors: Weiss Carol D , Wang Wei , Lu Yun , Billings Monisha , Eick-Cost Angelia , Couzens Laura , Sanchez Jose L , Hawksworth Anthony W , Seguin Peter , Myers Christopher A , Forshee Richard , Eichelberger Maryna C , Cooper Michael J
Published: December 2019

Background

Antibodies that inhibit hemagglutination have long been considered a correlate of protection against influenza, but these antibodies are only a subset of potentially protective antibodies. Neutralizing and neuraminidase antibodies may also contribute to protection, but data on their associations with protection are limited.

Methods

We measured preoutbreak hemagglutinin pseudovirus neutralization (PVN) and neuraminidase inhibition (NAI) antibody titers in unvaccinated military recruits who experienced an H3N2 influenza outbreak during training. We conducted a case-control study to investigate the association between titers and protection against influenza illness or H3N2-associated pneumonia using logistic regression.

Results

With every 2-fold increase in PVN titer, the odds of medically attended polymerase chain reaction–confirmed H3N2 infection (H3N2+) decreased by 41% (odds ratio [OR], 0.59; 95% confidence interval [CI], .45 to .77; P < .001). Among those who were H3N2+, the odds for pneumonia decreased by 52% (OR, 0.48; CI, .25 to .91; P = .0249). With every 2-fold increase in NAI titer, the odds of medically attended H3N2 infection decreased by 32% (OR, 0.68; 95% CI, .53 to .87; P = .0028), but there was no association between NAI titers and H3N2-associated pneumonia. There was also no synergistic effect of PVN and NAI antibodies.

Conclusions

PVN and NAI titers were independently associated with reduced risk of influenza illness. NAI titers associated with protection had greater breadth of reactivity to drifted strains than PVN titers. These findings show that PVN and NAI titers are valuable biomarkers for assessing the odds of influenza infection.
Inter-industry wage inequality: persistent differences and turbulent equalisation
Authors: Mokre Patrick , Rehm Miriam
Published: December 2019

The empirical stylised fact of persistent inter-industry wage differentials is an enduring challenge to economic theory. This paper applies the classical theory of ‘real competition’ to the turbulent dynamics of these inter-industrial wage differentials. Theoretically, we argue that competitive wage determination can be decomposed into equalising, dispersing and turbulently equalising factors. Empirically, we show graphically and econometrically for 31 US industries in 1987–2016 that wage differentials, like regulating profit rates, are governed by turbulent equalisation. Furthermore, we apply a fixed-effects OLS as well as a hierarchical Bayesian inference model and find that the link between regulating profit rates and wage differentials is positive, significant and robust.
Active-absorbing phase transition and small-world behaviour in Ising model on finite addition type networks in two dimensions
Authors: Mullick Pratik , Sen Parongama
Published: December 2019

We consider the ordering dynamics of the Ising model on a square lattice where an additional fixed number of bonds connect any two sites chosen randomly from a total of $N$ lattice sites. The total number of shortcuts added is controlled by two parameters $p$ and $\alpha$ for fixed $N$. The structural properties of the network are investigated which show that the small-world behaviour is obtained along the line $\alpha=\frac{\ln (N/2p)}{\ln N}$, which separates regions with ultra-small world like behaviour and short-ranged lattice like behaviour. We obtain a rich phase diagram in the $p-\alpha$ plane showing the existence of different types of active and absorbing states to which the Ising model evolves to and their boundaries.