bluuebunny/crossref_metadata_2025_split huggingface dataset:
Structural and Magnetic Properties of Granular Co-ZrO2 Films
Authors: Konstantinović Z , Muro M García del , Hattink B J , Varela M , Batlle X , Labarta A 
Published: June 2019

AbstractWe present here the growth of Co-ZrO2 granular films by pulsed laser deposition (PLD). Co-ZrO2 prepared with PLD is an ideal system for investigating the properties of magnetic nanoparticle since the Co-ZrO2 interfaces are of high quality with no evidence of intermixing. The average composition of the samples is determined by x-ray photoemission spectroscopy and microprobe exsperiments. High resolution scanning electron microscopy shows existence of a regular distribution of Co nanoparticles embedded in the amorphous ZrO2 matrix. Ferromagnetic correlations among the Co nanoparticules are evident in the field-cooled state. The mean particle size and width of the distribution are determined by fitting the low-field magnetic susceptibility and isothermal magnetization in the paramagnetic regime to a distribution of Langevin functions. Magnetoresistance confirms its origin from the particle magnetization and also validates information about the particle distribution.
Fabrication of Core-shell Type FeCo-Au (Ag) High Moment Magnetic Nanoparticles
Authors: Bai Jianmin , Xu Yunhao , Wang Jian-Ping 
Published: June 2019

AbstractWe developed a physical vacuum deposition technique combining an on-line sputtering/evaporation process with an integrated nanocluster deposition process to prepare core-shell type nanoparticles. High magnetic moment (Fe60Co40)coreAushell and (Fe60Co40)coreAgshell superparamagnetic nanoparticles with controllable particle size of 10 – 20 nm and Au/Ag shell thickness of 1 – 3 nm were prepared successfully by using method. Au shell is not only functional for the potential biocompatibility but also the key to prevent oxidation of FeCo nanoparticles. Saturation magnetization of (Fe60Co40)coreAushell nanoparticles was found three times higher than that of iron oxide nanoparticles. This novel technique enables us to control independently the dimensions of core and shell and select individually materials for core and shell for other core-shell type nanoparticles.
Synthesis of Magnetic Self-Assembled Nickel-Rich Oxide Nanowires Using a Novel Electrochemical Process
Authors: Bhargava Yash V. , Thorne Shawn A. , Mintz Todd S. , Hyams Tzipi Cohen , Radmilovic Velimir , Suzuki Yuri , Devine Thomas M. 
Published: June 2019

AbstractWe present a novel self-assembly nanowire synthesis technique capable of producing nickelrich oxide nanowires of lengths up to 20μm and diameters as small as 5nm. The method was discovered while examining the oxidation of Alloy 600 (nickel- 15.5a/o Cr, 8a/o Fe) in a pressurized water reactor environment. The nanowires have been grown on substrates of Alloy 600 and other nickel-chromium substrates exposed to oxidizing conditions in 1500psi pressurized water with 2ppm lithium and 1200ppm boron at temperatures ranging from 238°C to 288°C. Oxidizing conditions can be controlled in one of two ways: by controlling the aqueous solution's dissolved oxygen concentration, or by use of a potentiostat. Compositional studies performed via energy dispersive spectroscopy (EDS) using a transmission electron microscope (TEM) indicate the content of the nanowires grown on Alloy 600 to be 49a/o oxygen, 47a/o Ni, and 4a/o Fe. Preliminary TEM analysis has revealed the nanowires to be single crystalline with an aspect ratio up to 1000:1. The nickel-rich oxide nanowires are particularly exciting because of their functional properties. The oxide composition of the nanowires gives them an inherent resistance to electrochemically aggressive environments, such as ones found in the body or many other aqueous solutions, in contrast to simple metal nanowires, which are susceptible to corrosion in such environments. Most importantly, analysis with a superconducting quantum interference device (SQUID) magnetometer indicates that the nickel-rich oxide nanowires are ferromagnetic with a coercivity of approximately 850e and a remnant field of 0.032emu/g at 300K.
Attenuation of Protein Adsorption on Static and Vibrating Magnetic Nanowires
Authors: Ainslie Kristy M. , Sharma Gaurav , Dyer Maureen A. , Grimes Craig A. , Pishko Michael V. 
Published: June 2019

AbstractThe research described here investigates the hypothesis that nanoarchitecture contained in a nanowire array is capable of attenuating the adverse host response, biofouling, generated when medical devices, such as sensors, are implanted in the body. This adverse host response generates an avascular fibrous mass transfer barrier between the device and the analyte of interest, disabling the sensor. Numerous studies have indicated that surface chemistry and architecture modulated the host response. These findings lead us to hypothesize that nanostructured surfaces will significantly inhibit the formation of an avascular fibrous capsule. We are investigating whether vibrating magnetostrictive nanowires, formed in nanowire arrays, can prevent protein and cell adhesion. Magnetostrictive nanowires are fabricated by electroplating a ferromagnetic metal alloy into the pores of a nanoporous alumina template. The ferromagnetic nanowires are made to vibrate by altering the magnetic field surrounding the wires. Enzyme-linked immunosorbent assay (ELISA) and other protein assays were used to study protein adhesion on the nanowire arrays. These results display a reduced protein adhesion per surface area of static nanowires. The vibrating nanowires show a further reduction in protein adhesion, compared to static wires. Studies were also preformed to investigate the effects of nanoarchitecture have on cell adhesion. These studies were performed with both static and vibrating nanowires. Preliminary protein adhesion studies have shown that a nanowire arrays modulate protein adhesion in vitro.
Room-Temperature Growth of Carbon Nanofibers
Authors: Vohs Jason K. , Raymond Jeffery E. , Brege Jonathan J. , Rozeveld Steven , Williams Geoffrey L. , Fahlman Bradley D. 
Published: June 2019

AbstractWe describe the growth of amorphous carbon nanofibers (CNFs) from iron-encapsulated dendrimer catalysts at ambient temperature and pressure conditions. Both fourth-generation poly (propyleneimine) (PPI) and poly(amidoamine) (PAMAM) dendrimers were suitable macromolecular hosts for the catalytic species. Average nanofiber diameters range from 10 - 15 nm, with lengths in excess of 20 microns.
Dynamics of Silicon Nanoparticle Synthesis by Pulsed Laser Ablation
Authors: Murray P.T. , Grazulis L. 
Published: June 2019

AbstractSi nanoparticles have been synthesized by ablating a Si target in Ar with 355 nm laser radiation. The nanoparticle size distribution has been determined in real time by laser-induced time of flight mass spectrometry. Under these conditions, nanoparticles that are formed in 1.0 and 2.0 Torr of background Ar gas exhibit log-normal size distributions with most probable diameters of 2.6 and 3.0 nm, respectively. The speed distribution of the nanoparticles has been determined by varying the time delay between the ablation and photoionization lasers. The results indicate that the most probable speed of the nanoparticles, after formation and a 25 mm drift in background Ar, is 100 m/s. Finally, there is a deviation of the size distribution from the log-normal distribution at small nanoparticle sizes. This is attributed to multiple ionization of the nanoparticles. Confirming evidence for multiple ionization is provided by the atomic and mass spectra which show peak broadening due to Coulomb explosion.
Preparation of Free-Standing PZT and Gold Nanoparticles
Authors: Das R. N. 
Published: June 2019

AbstractFree-standing PZT (Lead Zirconate Titanate ) and Gold nanoparticles (ceramic and metal) have been prepared by complex process. In case of PZT, the process involves the preparation of metal ion complex (ligand) solution followed by evaporation. Complete evaporation results in fluffy dried mass. Calcination of dried mass at low temperature produces free-standing PZT nanoparticles. The concept of the process involves choice of correct metal ion complex, stoiochiometry and drying conditions to produce free-standing individual nanoparticles. Similar process has been used to prepare free-standing gold nanoparticles where individual gold form complex with the ligands (complexing agents) to produce free-standing nanoparticles.
Synthesis, Characterization, and Growth Mechanism of Silicon Oxide Nanowires
Authors: Dong Lifeng , Coulter Michael , Ford  , Jiao Jun 
Published: June 2019

AbstractTwo fabrication methods have been investigated to synthesize silicon oxide nanowires. One was catalytic thermal evaporation method in which silicon monoxide was used as the precursor and Au particles served as the catalysts. Using nanosphere lithography, patterned nanowires were obtained and their growth positions were controlled by the locations of Au catalysts. For the second method, without silicon monoxide as the precursor and without the aid of Au catalyst, silicon oxide nanowires directly formed along the <110> direction of the silicon substrate only with the introduction of hydrogen gas. A series of experiments were carried out to study effects of reaction time, temperature, and hydrogen on the growth of the nanowires. Also, various electron microscopy techniques were utilized to characterize their morphologies and internal structures and to analyze their compositional distributions. In this paper, the characterization of different silicon oxide nanowires and their formation mechanisms in relation to both preparation methods are discussed.
Synthesis and Aggregation of BiBi2S3Nanocapsules
Authors: Vega-González Marina , Bokhimi Xim , Aguilar-Franco Manuel , Morales Antonio , García-Ruiz Amado F. 
Published: June 2019

AbstractNanocapsules of Bi2S3 with diameters between 5 and 10 nm and shells with an amorphous atomic distribution were synthesized at room temperature, with bismuth nitrate and thiourea as precursors. Aging the solution for several days a black powder precipitated made of a mixture of one amorphous phase and crystalline Bi2S3. When two capsules interacted between each other, the capsule regions in contact crystallized into bismuth sulfide, which explains the origin of the crystalline phase observed in the X-ray diffraction pattern. At this temperature, aggregation of the small nanocapsules also gave rise to necklaces of capsules, which eventually gave rise to nanotubes; these necklaces ordered forming bundles parallel to their largest dimension. When the solution was annealed at temperatures lower than 100 °C, aggregation gave rise to capsules as large as 1 μm in diameter, and tubes with similar diameters; in this case aggregation occurred between small and large nanocapsules. Because of the monomers aggregating had an external spherical symmetry and the low annealing temperatures, which were not high enough to produce sintering, all capsules and tubes formed during aggregation had porous walls, making these materials interesting for many applications.
Formation of ZnO Doped with Mn Thin Film by Electrodeposition and Magnetic Behaviour.
Authors: Abid M. , Terrier C. , Ansermet J-P , Hjort K. 
Published: June 2019

AbstractFollowing the theory, ferromagnetism is predicted in Mn- doped ZnO, Indeed, ferromagnetism above room temperature was recently reported in thin films as well as in bulk samples made of this material. Here, we have prepared Mn doped ZnO by electrodeposition. The samples have been characterized by X-ray diffraction and spectroscopic methods to ensure that the dopants are substitutional. Some samples exhibit weak ferromagnetic properties at room temperature, however to be useful for spintronics this material need additional carriers provided by others means.
Preparation of Copper Nanowire/Polymer Nanocomposites by Melt Mixing
Authors: Krantz Matthew J. , Gelves Genaro A. , Sundararaj Uttandaraman , Haber Joel A. 
Published: June 2019

AbstractA scaleable synthesis of metal nanowires has been developed using ac electrodeposition into the pores of porous aluminum oxide (PAO) templates, through the resistive barrier layer. Gram quantities of high aspect-ratio Cu nanowires (25 nm in diameter by ∼20,000 nm in length) were liberated by dissolving the PAO film with sodium hydroxide solution. The agglomerated nanowires were dispersed in methanol by ultrasonication and collected by centrifugation or filtration. The nanowires were blended into amorphous polyamide by melt processing. The dispersion and percolation of the nanowires in the polymer was investigated by electron microscopy and conductivity measurements as a function of nanowire loading and processing route. Mechanical properties were evaluated by tensile testing of miniature dog bone specimens.
Synthesis of Silicon Nanowires and their Heterostructures by Thermal Chemical Vapor Deposition
Authors: Jang Woo-Sung , Bae Seung Yong , Park Jeunghee 
Published: June 2019

AbstractThe Si nanowires were synthesized using a novel catalytic thermal reaction under Ar flow. The average diameter is in the range of 50 ∼ 100 nm. They consist of defect-free single-crystalline cubic structure with the [111] growth direction. The thickness of amorphous oxide outer layers was controllable by growth conditions or surface treatment. In order to protect the oxidation, the Si nanowires were coated with boron nitride layer by the reaction of boron oxide mixture with NH3.
Wet Chemical Synthesis of Germanium Nanocrystals
Authors: Lu Xianmao , Korgel Brian A. , Johnston Keith P. 
Published: June 2019

AbstractSupercritical CO2 (sc-CO2) was first time utilized to make germanium (Ge) nanocrystals by thermolysis of diphenylgermane (DPG) or tetraethylgermane (TEG) with octanol as capping ligand at 500°C and 27.6 MPa. A new approach to prepare Ge nanocrystals of high chemical yield by reduction of GeI2 with LiAlH4 in trioctylphosphine (TOP) at 300°C is also presented. In both cases, Ge nanoparticles with high crystallinity were observed with high resolution transmission electron microscopy (HRTEM), and the presence of Ge was confirmed by X-ray diffraction (XRD) pattern. Compared to the supercritical organic solvents investigated in the previous study to make Ge nanoparticles, the reaction in sc-CO2 produced much less organic contaminants and made the removal of by-products and cleaning of the nanocrystals much easier. While Ge nanoparticles were synthesized in sc-CO2 with DPG and octanol, bulk Ge instead of nanoparticles was obtained without the presence of CO2 at the same concentration of DPG and octanol. High chemical yield of up to 75% was achieved for the Ge nanoparticles made from GeI2 with TOP, and only minimal cleaning is required to obtain Ge nanocrystals with high purity.
Depth Profiling of Mechanical Properties on the Nanoscale of Single-Layer and Stepwise Graded DLC Films by Nanoindentation and AFM
Authors: Ziebert C. , Ulrich S. , Stüber M. 
Published: June 2019

AbstractThe strong ion bombardment, applied during sputter deposition of diamond-like carbon films (DLC), which is needed to promote the growth of the sp3-bonded hard phase, inevitably is accompanied by compressive stress generation, thus limiting their maximum thickness. Gradient coatings with gradients in composition, constitution or properties are a well-known concept to manage such stress problems. The stepwise graded layer concept adjusts a graded constitution of the growing carbon film by a stepwise increase of the ion energy, i.e. the substrate bias voltage, during magnetron sputtering. To study the influence of the layer thickness on the expansion of the interface regions between the layers deposited with different bias voltage, samples with increasing deposition time of the top layer and thus thickness ratio were investigated by using the small angle cross-section nanoindentation method (SACS). It was revealed that the thickness of the interface regions is linearly dependent on the thickness ratio of the graded layers, which might be an evidence for stress-induced diffusion and relaxation processes in the carbon network. By using microindentation with a Berkovich indenter and ex-situ AFM-imaging it was found that all graded films exhibited higher Berkovich thresholds for crack development and thus better crack resistance than the hardest single-layer film and kept a high hardness value of about 4000 HV0.005.
Deformation of Highly Loaded Alumina Reinforced Aluminium Composites: Internal Damage and the Size Effect
Authors: Müller Randoald , Mortensen Andreas 
Published: June 2019

AbstractThe pressure infiltration of densely packed alumina particle preforms with molten aluminium produces defect-free composites containing roughly equal proportions of metal and ceramic. The process affords considerable latitude in microstructural design of the resulting composites. In particular, the matrix can be kept microstructurally simple, and the size of the reinforcement can be varied roughly between 3 and 100 μm.Despite their high ceramic loadings, these composites display appreciable plasticity, often deforming in tension to elongations of several percent before breaking. Beyond yield, their flow stress is largely governed by that of the matrix; this matrix, in turn, is a metal deforming between hard inclusions only a few micrometres apart. As is known from the composite literature, the high constraint imposed by the reinforcement on matrix deformation is manifest in a “size-effect”, whereby the matrix flow stress, and hence that of the composite, depend on the microstructural scale of the composite, increasing as the reinforcement size decreases.We present recent results on this phenomenon from an investigation of pressure-infiltrated alumina reinforced aluminium composites. The composites are model materials in that (i) their matrix (high-purity aluminium, or binary aluminium-copper alloys) is kept metallurgically simple, (ii) the matrix/reinforcement interface is mechanically strong and free of interfacial reaction products, and (iii) the reinforcement is monosized and uniformly distributed throughout the composite.We describe a method of data analysis of this effect that takes into account both the complexity of the underlying mechanical problem and the influence of internal damage, which often develops extensively in such materials. Recent results for the non-linear deformation of power-law composites are used in conjunction with measurements of the rate of internal damage in these materials to derive in-situ flow curves of the matrix within such composites. Results show that there is a strong and systematic size effect for yield and plastic flow of highly reinforced pure aluminium; data also show an influence of the particle shape in additional to particle size. With binary Al-Cu alloys, the data show that there is a size effect on yield of the composite, but not on the flow stress upon subsequent deformation.
Mechanical Properties of Textured Alumina Prepared by Colloidal Processing in a Strong Magnetic Field
Authors: Suzuki Tohru S. , Uchikoshi Tetsuo , Morita Koji , Hiraga Keijiro , Sakka Yoshio 
Published: June 2019

AbstractThe development of texture can be controlled by slip casting and EPD in a strong magnetic field followed by heating even for diamagnetic ceramics such as alumina. We mesured the mechanical properties of the textured alulmina and the alumina/alumina laminar composites with different crystalline-oriented layer.
Synthesis and Characterization of Layered Double Hydroxides/Nafion Composites for Fuel Cell Application
Authors: Raghavan Dharmaraj , Abayomi Bolnale , Harewood Miriam , Abudu Sheriff , Williams Elizabeth , Butcher Raymond , Raghavan Dharmaraj 
Published: June 2019

AbstractIn this study, magnesium-aluminum (Mg-Al) based LDHs with different Mg2+/Al3+ ratios were prepared by co-precipitation method and modified with perfluorooctane-sulfonic acid tetraethylammonium salt (PFOSA). X-Ray Diffraction (XRD), Atomic Force Microscopy (AFM), Fourier Transfer Infrared spectroscopy (FTIR) and Thermogravimetric Analysis (TGA) were carried out to obtain the structural and thermal characteristics of resulting materials. The organo-modified LDHs have been used in the formulation of Nafion® nanocomposites. Nanocomposite membranes were prepared by casting of LDH/PFOSA nanoparticles dispersed in Nafion® solution. Then, modified LDH/Nafion composite membranes were evaluated for water retention capability at ambient and elevated temperature.
Uniform Accuracy of the Quasicontinuum Method [PowerPoint Submission]
Authors: Yang Jerry Z. 
Published: June 2019

AbstractThe accuracy of the quasicontinuum method is studied by reformulating the summation rules in terms of reconstruction schemes for the local atomic environment of the representative atoms. The necessary and sufficient condition for uniform first order accuracy and consequently the elimination of the “ghost force” is formulated in terms of the reconstruction schemes.The quasi-nonlocal approach is discussed as a special case of this condition.Examples of reconstruction schemes that satisfy this condition are presented.Transition between atom-based and element-based summation rules are studied.
Computer Simulation of Fracture in Aerogels
Authors: Good Brian 
Published: June 2019

AbstractAerogels are of interest to the aerospace community primarily for their thermal properties, notably their low thermal conductivities. While the gels are typically fragile, recent advances in the application of conformal polymer layers to these gels has made them potentially useful as lightweight structural materials as well. In this work, we investigate the strength and fracture behavior of silica aerogels using a molecular statics-based computer simulation technique. The gels' structure is simulated via a Diffusion Limited Cluster Aggregation (DLCA) algorithm, which produces fractal structures representing experimentally observed aggregates of so-called secondary particles, themselves composed of amorphous silica primary particles an order of magnitude smaller. We have performed multi-length-scale simulations of fracture in silica aerogels, in which the interaction between two secondary particles is assumed to be described by a Morse pair potential parameterized such that the potential range is much smaller than the secondary particle size. These Morse parameters are obtained by atomistic simulation of models of the experimentally-observed amorphous silica “bridges,” with the fracture behavior of these bridges modeled via molecular statics using a Morse/Coulomb potential for silica. We consider the energetics of the fracture, and compare qualitative features of low-and high-density gel fracture.
Void Evolution via Coupled Creep, Diffusion and Electromigration in Confined Nano-interconnects
Authors: Kim Dongchoul , Lu Wei 
Published: June 2019

AbstractA three dimensional electromigration model is presented to account for void evolution in small scale interconnects. The model provides better understanding of the evolution process by considering concurrent kinetics of creep flow and surface diffusion. The multiple kinetics and energetics are incorporated into a diffusive interface model. Simulations show that a shape stable in surface diffusion can become unstable in a creep dominated process, which leads to a quite different void morphology.
Interplay of Shock-induced Melting and Alloying in Nanostructured Multilayer Films
Authors: Zhao Shijin , Germann Timothy C. , Strachan Alejandro 
Published: June 2019

AbstractWe identify a shock-induced melting and great facilities of the melting in accelerating subsequent alloying reactions in nanostructured Ni/Al multilayer films using a novel molecular dynamics technique, which captures the initial shock transit as well as the subsequent long time scale alloying process. We observe a pronounced increase of the pressure in the melting process (i.e., a process of coexistence of solid and liquid phases). As soon as the melting completes, the temperature increases dramatically indicating a start of explosive alloying reactions and the pressure starts to decrease. The pressure going up or down is determined by the competition between melting and alloying reactions.