bluuebunny/crossref_metadata_2025_split huggingface dataset:
The SPM study of oligonucleotides consisting of repeated nucleotide sequences
Authors: Sharipov T I , Garafutdinov R R , Amangulova I T , Bakhtizin R Z 
Published: December 2019

Abstract
Recently, the study of the dependence of the physical characteristics of DNA molecules on their structure has become of considerable interest. Various methods are used to conduct such research, among which scanning probe microscopy (SPM) is becoming increasingly important. In this work, the short single-stranded DNA molecules consisting of dC nucleotides are visualized and their conductivity is investigated by SPM methods. It has turned out that the distribution of DNA molecules on the surface of the substrates is uniform. The measured current-voltage characteristics have made it possible to estimate the differential electrical resistance of individual d(C)12 molecules.
Conductive AFM study of the electronic properties of individual epitaxial GaN nanowires
Authors: Sharov V , Bolshakov A , Fedorov V , Shugurov K Yu , Mozharov A M , Sapunov G A , Mukhin I S 
Published: December 2019

Abstract
In this work, we use conductive atomic force microscopy (CAFM) to study the impact of substrate surface preparation and buffer layer composition on the electrical transport properties of GaN nanowires (NWs). I-V curves of single NWs from seven differently prepared samples were obtained. The tip of atomic force microscope (AFM) was used as a top conductive electrode to create stable electric contact to NW free upper grain, while the bottom contact was established between the highly doped Si substrate and a grounded sample holder of the AFM device. Single NW I-V curves were compared to those of NW arrays. The difference between them was discussed.
SEM and SPM investigations of the surface of antifriction aluminium alloys of the system Al-5%Si-4%Cu-6%Sn
Authors: Shcherbakova O O , Muravyeva T I , Zagorskiy D L , Shkalei I V , Lapitskaya V A , Kuznetsova T A 
Published: December 2019

Abstract
Two antifriction alloys based on the Al–5%Si–4%Cu–4%Sn system with the addition of bismuth, lead, and cadmium were investigated. The effect of these elements on the change in surface topography and the tribological properties of the samples was studied. Tribological tests simulating the work of the friction unit were carried out using “shoe-roller” scheme. After heat treatment in both alloys, the phase components acquired a globular shape. Mass transfer between the shoe and the roller led to the formation of a film of secondary structures of variable thickness on the roller surface. SEM and EBSD allowed observing a near-surface layer (50-100 μm thick) with a modified structure and grain shape. SPM made it possible to evaluate the difference in the mechanical properties of the surface layer at the nanoscale level. It was shown that the material was strengthened in the process of friction.
Formation of the maze domain structures in lithium niobate as a result of multiple pulse irradiation by infrared laser
Authors: Shur V Ya , Mingaliev E A , Kosobokov M S , Makaev A V 
Published: December 2019

Abstract
The formation of the maze domain structures in the plates of congruent lithium niobate single crystal caused by multiple irradiation of infrared pulsed laser at different plate temperatures was studied. Four stages of domain evolution with increasing pulse number were distinguished. The dependence of the formed self-organizing domain structures on pulse number and sample temperature was revealed. Suppression of the domain formation at the elevated temperatures was attributed to increasing ionic conductivity, which led to decreasing the switching field.
Forming-free resistive switching in nanocrystalline hafnium oxide films
Authors: Smirnov V A , Tominov R V , Avilov V I , Avakyan A A , Ageev O A 
Published: December 2019

Abstract
This work presents the results of the investigations of resistive switching effect in Si(100)/HfO2 structure. It was shown that resistive switching from HRS to LRS occurred at 0.4±0.1 V, and from LRS to HRS at -0.5±0.1 V. An increase in the sweep voltage from 1 to 5 V led to a decrease in the HRS/LRS ratio from 606±36 to 204±11. Thus, it was shown that the nanocrystalline HfO2 film resistance varied within two orders of magnitude at a sweep voltage of 1 V within 15 measurements. The results can be useful for manufacturing neuromorphic systems based on forming-free nanocrystalline HfO2 films.
Microstructure of barium strontium titanate based glass-ceramics doped by Ce and La
Authors: Turygin A P , Chezganov D S , Baturin I S , Song X , Zhang Y , Shur V Ya 
Published: December 2019

Abstract
The microstructure and surface morphology of (Ba0.8,Sr0.2)TiO3 based glass-ceramics with different amounts of La and Ce were studied. It was shown that the addition of the 1.5% La and >2%Ce led to formation of dendrite-like structures. The isolated clusters of ferroelectric phase were found in all investigated samples. Fraction of ferroelectric phase was about 0.75% for La addition and 0.25% for Ce addition.
Polyurethane foam modified with borohydride: preparation and possibilities of using for synthesis of gold nanoparticles and their nanocomposites
Authors: Isachenko A I , Apyari V V , Melekhin A O , Garshev A V , Volkov P A , Dmitrienko S G 
Published: December 2019

Abstract
The present work describes preparation of polyurethane foam modified with borohydride. Adsorption of borohydride from alkaline solutions in presence of a cationic surfactant is discussed. The polyurethane foam modified with borohydride possesses reductive ability with respect to Au(III). Possibilities of the new material for synthesis of gold nanoparticles are described. This solid reducting agent is convenient for use in the synthesis of nanoparticles, since it ensures precise dosing of a reductant while desorbed from polymer. Gold nanoparticles can be synthesized both in solution and on the polymer surface by varying reagents concentrations during the preparation of modified polyurethane foam.
Synthetic analogues of natural titanosilicate mesoporous minerals as potential functional materials. Synthesis and application
Authors: Nikolaev A I , Gerasimova L G , Maslova M V , Shchukina E S 
Published: December 2019

Abstract
Phase formation upon hydrothermal crystallization in the Na2O-TiO2-SiO2-H2SO4- H2O system has been studied in depth. The obtained results provided the basis for the development of technology for new types of ion-exchangers with the structure of the mineral ivanyukite - Na4(TiO)4(SiO4)34-6 H2O. It was shown that an excessive amount of Na and Si with respect to Ti (mol) and an alkaline medium up to pH 12 affect the rate of the ivanyukite crystallization. The optimal conditions producing the pure ivanyukite phase with designed structure, chemical composition and morphology have been found. The framework composes corner-sharing SiO4 tetrahedra and TiO6 octahedra linked through bridging oxygen atoms and provide pore system with channels containing H2O molecules and exchangeable Na+cations. The synthetic ivanyukite with wide-pore microporous framework is considered to be perspective cation-exchanger.
Morphological study of PM2.5 by SEM-EDS in Ulaanbaatar
Authors: Tuvjargal N , Enkhtsetseg L , Shagjjamba D , Zuzaan P 
Published: December 2019

Abstract
A morphological and elemental composition of PM2.5 in air pollution of Ulaanbaatar by Scanning Electron microscopy (SEM) combined X-ray Energy Dispersive Spectrometry (EDS) were investigated. The morphological parameters were measured using the 5k magnification picture of SEM and analyzed the 752 individual particles of the 25 days (winter-10, summer-15) sample of the PM2.5. The size distribution shown the ~45% of particles were most harmful fraction of particulate matters for human health (less 0.4μm). These fraction particles increased up to 92% in winter. It was shown that ultrafine and irregular PM2.5 results from the combustion. The results of determining the elemental composition of these individual particles are presented.
Dispersed-colloidal fuel systems
Authors: Baranova M , Grishina I , Damdinov B , Gomboev R 
Published: December 2019

Abstract
A substantiation of the action mechanism of alkaline additives on the rheological characteristics of binary fuel systems is proposed, which will allow us to proceed to numerical methods for studying the technological processes of production. The possibility of increasing the stability of the suspension by using a nanomodifier obtained by ultradispersing to a submicron size of a portion of the same suspension is shown.
Numeric Modeling of Phononic Crystal with Time-Dependent Properties
Authors: Demin A , Damdinov B , Baloshin Y 
Published: December 2019

Abstract
The research is devoted to numeric modeling of phononic crystals with time-depended properties of periodic structure. There are many works describing phononic crystal with a tunable bandgap. The mechanism of restructuring can have a different physical nature. In this turn, we developed model of phonon crystal with fast-changing properties, where frequency of changing and propagating wave have the same order. The influence of time-dependent characteristics on propagation of wave packets, waves with different initial phase is shown in this work. Parameters of the crystal cell are given by time-dependent; signal propagation has significant differences from the static case. It was shown that under certain conditions a phononic crystal acquires the properties of a phase filter.
Wire electro spark machining and characterization studies on Ti50Ni49Co1, Ti50Ni45Co5 and Ti50Ni40Co10 alloys
Authors: Soni Hargovind , Mashinni P M 
Published: December 2019

Abstract
The wire electrical discharge machining process (WEDM) is high demand and influenced by various input process parameters namely pulse duration, voltage, wire diameters and wire material. In this research, a smart material made of TiNiCo alloy is investigated to study the machinability using WEDM process. The pulse duration and servo voltage varied to perform the experiments on Ti50Ni49Co1 Ti50Ni45Co5 and Ti50Ni40Co10 smart materials for bone staple applications which were designed by ELCAM software and generated G-code for machining with same software. L-25 orthogonal array used for machining of selected alloys, which is created (L-25 orthogonal array) through Taguchi design of experiment. From the experiments, an analysis was made to study the amount of material removal and average roughness as a response. Further machined areas were subjected to metallurgical characterization techniques such as surface topography, EDS analysis, residual stress calculation and wear mechanism. Tensile residual stress was noticed at higher values of outputs while lower values of residual stress at lower values of outputs which were also confirmed through microstructure and surface topography that smoother surface has been found at lower values of outputs. Moreover, the higher value of residual stress has been noticed on the machined surface of Ti50Ni40Co10 alloy while lower on the machined surface of Ti50Ni49Co1 alloy. Copper (Cu), Zinc (Zn), Carbon (C) and Oxygen (O) were found as additional elements on the machined surface during the EDS analysis of machined components for each alloy.
Rice husk-derived carbon@SnO2@graphene anode with stable electrochemical performance used in lithium-ion batteries
Authors: Liang Shuqi , Yu Kaifeng , Li Yi , Liang Ce 
Published: December 2019

Abstract
In this study, we adopted a novel method to synthesize a rice husk-derived carbon@SnO2@reduced graphene oxide (rGO)composite with a multi-level structure as an anode electrode for lithium-ion batteries. The carbon source of composite was cellulose extracted from RH. The material exhibits excellent performance of LIBs with large reversible capacity and outstanding cycle performance. It shows a reversible capacity of 1206.9 mAhg−1 at a current density of 0.2C after 100 cycles. Excellent cycle performance is due to unique multi-level structure, which increases active site of lithium ion. Furthermore, SnO2 nanoparticles (SnO2 NPs) and carbon skeleton have strong chemical bonds to prevent SnO2 NPs from falling out of the three-dimensional network during cycling., thereby making material a promising anode material for LIBs.
A comparative study of dry sliding wear behaviour of sillimanite and rutile reinforced LM27 aluminium alloy composites
Authors: Gupta Rahul , Sharma Sandeep , Nanda Tarun , Pandey O P 
Published: December 2019

Abstract
The present work compares the dry sliding wear characteristics of sillimanite reinforced and rutile reinforced LM27 aluminium alloy based composites prepared by stir casting process. Particles in the size range of 1–32 μm were added in 5, 10, and 15 wt%. Microstructure, nanohardness, coefficient of friction, and wear rate characteristics were evaluated. Optical microscopy revealed uniform distribution of both sillimanite and rutile particles in the matrix. The hardness of sillimanite reinforced composites was higher than rutile reinforced composites. Further, the wear resistance of sillimanite reinforced composites was superior to rutile reinforced composites. However, coefficient of friction values of sillimanite particle reinforced composites were higher than the rutile particle reinforced composites. SEM-EDS analysis of wear track and wear debris revealed that abrasive wear and adhesion/delamination mechanisms were responsible for the wear of composites at low and high applied load conditions respectively.
Influences of Mg and Mn doping on structure, B-site ordering and microwave dielectric properties of Ba(Co1/3Nb2/3)O3 ceramics
Authors: Cui Xuejiao , Liu Liang , Li Hao , Liu Fei , Cheng Lijing , Liu Shaojun 
Published: December 2019

Abstract
Influence of Mg and Mn doping on structure and microwave dielectric properties of Ba(Co1/3Nb2/3)O3 (BCN) ceramics with complex perovskite structure is investigated systematically. X-ray diffraction and Raman spectrum investigations show that doping Mg and Mn into BCN ceramics is helpful for improving the quality factor (Q · f value) resulted from enhanced B-site 1:2 ordering degree. Mg- doped samples show higher ordering degrees and larger Q · f values than Mn- doped counterparts. The sintering density, grain size, 1:2 B-site ordering structure and microwave dielectric properties of BCN ceramics show a strong dependence on Mg and Mn doping content. The sintering density of BCN ceramics can be increased significantly by doping a small amount of Mg and Mn. However, further increase in doping content results in the decrease of sintering density. τ

f
value of BCN ceramics can be tailored by doping of Mg into Co sites. The near-zero τ

f
value (∼0.64 ppm °C−1) is obtained when the Mg doping content is at x = 0.1. The ordering degree and Q · f value of Mg- and Mn- doped BCN ceramics increase significantly with increasing annealing time.
Theoretical study on the structural, electronic, and optical properties of BnCn (n = 1–13) clusters
Authors: Chen Xiaojie , Zhang Chen , Song Bin , He Pimo 
Published: December 2019

Abstract
We applied density functional theory (DFT) calculations to investigate the low-energy geometries and electronic characteristics of stoichiometric BnCn (n = 1–13) clusters. We performed harmonic vibration frequency analysis to ensure that the ground-state isomers are the real local minima. BnCn clusters tend to evolve from planar and annular structures to quasiplanar bowl structures to maintain the lowest structural energy as cluster size n increases. The clusters with even n have large HOMO–LUMO gaps and high stability. We used the time-dependent DFT (TDDFT) calculations to acquire the optical absorption spectra for the lowest-energy BnCn (n = 4, 6, 8, 10, 12) clusters. The clusters exhibit strong absorption in the ultraviolet region. With the increasement of n, the absorption of clusters, particularly that of the B8C8 cluster, intensifies in the visible region. Therefore, the clusters investigated in this work can be used to fabricate novel two-dimensional materials for visible-light absorption and have potential applications in various fields, such as catalysis.
Enhanced drug efficiency of doped ZnO–GO (graphene oxide) nanocomposites, a new gateway in drug delivery systems (DDSs)
Authors: Afzal H , Ikram M , Ali S , Shahzadi A , Aqeel M , Haider A , Imran M , Ali S 
Published: December 2019

Abstract
Graphene oxide (GO) nanosheets were doped to zinc oxide (ZnO) nanoparticles using a facile chemical deposition method. X-ray diffraction (XRD) confirmed the presence of hexagonal structure and increased peaks broadening upon doping. Undoped and ZnO doped GO sheets showed morphology like nanoparticles, nanorods and flakes were observed under transmission and field emission electron microscopies respectively. An increase in absorption was observed in absorption spectra upon doping recorded via UV-visible spectroscopy. The hydrogen bonding between functional groups of GO and ZnO is responsible for limiting maximum drug loading efficiency. GO doped ZnO has higher drug loading efficiency of about 89% compared to ZnO (82%) and this trend reverse in drug releasing process. This study will provide an efficient design of the drug delivery system for dissolution enhancement according to the required drug release.
Effect of sodium chloride as a porogen agent in mechanical properties of PLGA/HA nanocomposite scaffolds
Authors: Mokhtarzadegan M , Zebarjad S Mojtaba , Bahrololoom M E , Modarres M 
Published: December 2019

Abstract
In this study, the novel poly (lactic-co-glycolic acid)-Hydroxyapatite nanoparticles (PLGA/HA) nanocomposite scaffolds were fabricated with solvent casting and particulate leaching (SCPL) method. The role of sodium chloride (NaCl) particles with diameters of 250-400 μm as porogen agent in the mechanical strength of the produced scaffolds was evaluated. The prepared scaffolds were characterized using Fourier transform infrared (FT-IR), X‐ray diffraction (XRD), scanning electron microscopy (SEM), thermal gravimetric analysis (TGA) and compressive tests. The results showed the high compressive strength and homogenous porous structures for PLGA/HA nanocomposite scaffolds compared to pure PLGA due to the presence of HA nanoparticles in nanocomposites. Furthermore, the compressive strength of nanocomposite scaffolds increased by varying the weight ratio of hydroxyapatite nanoparticles to polymer (0, 20, 40 wt%) at constant salt ratio and decreased by increasing the weight ratio of salt particles to polymer from 1 to 3 wt% due to more porosity in nanocomposite scaffolds. These results confirmed that not only the nanocomposite scaffolds exhibited high mechanical properties, homogenous structures, as well as good porosity but also, they could be useful for bone tissue application.
Strong-field-induced single and double ionization dynamics from single and double excitations in a two-electron atom
Authors: Borisova Gergana D , Stooß Veit , Dingeldey Andreas , Kaldun Andreas , Ding Thomas , Birk Paul , Hartmann Maximilian , Heldt Tobias , Ott Christian , Pfeifer Thomas 
Published: December 2019

Abstract
Two-electron dynamics of an excited model atom interacting with moderately strong laser fields is analyzed in the time domain. We solve the time-dependent Schrödinger equation (TDSE) for two electrons confined to the same one-dimensional configuration space, accounting also for the electron-electron interaction. The computational method allows direct access to the time-dependent population of the relevant atomic states during and right after the interaction with a near-infrared (NIR) laser pulse. We compare the ionization dynamics of singly excited states and doubly excited states. We find that doubly-excited initial states exhibit enhanced double ionization yield, with non-trivial dynamics including contributions from direct and sequential processes, while the electrons leave the atom either back-to-back or in the same direction.
Social Support and Positive Coping Skills as Mediators Buffering the Impact of Childhood Maltreatment on Psychological Distress and Positive Mental Health in Adulthood: Analysis of a National Population-Based Sample
Authors: Su Yingying , D’Arcy Carl , Meng Xiangfei 
Published: December 2019

Abstract
There is little research on how childhood maltreatment influences the use of resilience mechanisms that are key to mental health outcomes in the face of adversity. We assessed the mediating roles of social support and positive coping skills in the relationships between childhood maltreatment and both psychological distress and positive mental health. We analyzed data from a national population survey, the 2012 Canadian Community Health Survey—Mental Health (CCHS-MH 2012, n = 25,113). Confirmatory factor analysis and structural equation modeling were used to model the relationships between childhood maltreatment, social support, and positive coping skills and their direct and mediated effect on psychological distress and positive mental health. Childhood maltreatment was found to be negatively associated with social support, positive coping skills, and positive mental health but positively associated with psychological distress. Social support and positive coping skills predicted higher rates of positive mental health but lower rates of psychological distress. Social support and positive coping skills partially mediated the negative consequences of childhood maltreatment on mental health outcomes. Surprisingly, no sex differences were observed among these associations. This research clearly demonstrates that social support and positive coping skills can mediate the negative impact of childhood maltreatment on mental health.
Neighborhood Privilege, Preterm Delivery, and Related Racial/Ethnic Disparities: An Intergenerational Application of the Index of Concentration at the Extremes
Authors: Shrimali Bina Patel , Pearl Michelle , Karasek Deborah , Reid Carolina , Abrams Barbara , Mujahid Mahasin 
Published: December 2019

AbstractWe assessed whether early childhood and adulthood experiences of neighborhood privilege, measured by the Index of Concentration at the Extremes (ICE), were associated with preterm delivery and related racial/ethnic disparities using intergenerationally linked birth records of 379,794 California-born primiparous mothers (born 1982–1997) and their infants (born 1997–2011). ICE measures during early childhood and adulthood approximated racial/ethnic and economic dimensions of neighborhood privilege and disadvantage separately (ICE-income, ICE-race/ethnicity) and in combination (ICE–income + race/ethnicity). Results of our generalized estimating equation models with robust standard errors showed associations for ICE-income and ICE–income + race/ethnicity. For example, ICE–income + race/ethnicity was associated with preterm delivery in both early childhood (relative risk (RR) = 1.12, 95% confidence interval (CI): 1.08, 1.17) and adulthood (RR = 1.07, 95% CI: 1.03, 1.11). Non-Hispanic black and Hispanic women had higher risk of preterm delivery than white women (RR = 1.32, 95% CI: 1.28, 1.37; and RR = 1.11, 95% CI: 1.08, 1.14, respectively, adjusting for individual-level confounders). Adjustment for ICE–income + race/ethnicity at both time periods yielded the greatest declines in disparities (for non-Hispanic black women, RR = 1.23, 95% CI: 1.18, 1.28; for Hispanic women, RR = 1.05, 95% CI: 1.02, 1.09). Findings support independent effects of early childhood and adulthood neighborhood privilege on preterm delivery and related disparities.