bluuebunny/crossref_metadata_2025_split huggingface dataset:
γ Phase Precipitation Processes in Quenched β Phase Cu-Zn-Al Alloys at an Electron Concentration of 1.53
Authors: Condó Adriana M , Arneodo Larochette Pierre , Tolley Alfredo 
Published: July 2020

Abstract
In the ternary Cu-Zn-Al alloys the bcc β phase is stable at high temperatures at electron concentrations (e/a) in the range from about 1.4 to 1.6 electrons per atom. Cu, Zn and Al atoms contribute with 1, 2 and 3 electrons, respectively. This region of stability is bounded by a β + γ twophase region at the high electron concentration border. If the P phase is retained at room temperature (RT) it transforms martensitically to a close packed structure. This transformation occurs without diffusion and provides information on the relative phase stability of the bcc and close packed structures. A detailed characterization of the microstructure of the parent bcc β phase and the martensite is thus essential for an adequate study of the transformation.
To retain the β phase at RT Cu-Zn-Al alloys must usually be quenched.
A Study on Precipitation in Clean Micro Alloyed Steels
Authors: Wang Yuanli , Liu Delu , Fu Jie , Zhu Jian 
Published: July 2020

Abstract
Much attention has been devoted to develop the new generation of microalloyed steels in recent years to meet the needs of high performance and low cost for the 21st century. The new type of steels is characterized by reduced carbon content, improved cleanness and refined grain size through the phase transformations.11'21 Precipitation of the carbonitrides in the steels is also one of the keypoints for controlling mechanical properties of the steels.
In the present work ultra-low carbon clean microalloyed steels, which contain 0.029∽0.047(wt)%C, 1.48∽1.54(wt)% Mn, 0.044∽0.052(wt)%Nb, 0.025∽0.044Ti(wt)%, 0.0015∽0.0020(wt)%B and 0.0045∽0.0070(wt)%N, were prepared in a vacuum induction furnace in laboratory. The contents of S and P of the steels are 0.0005(wt)% and 0.0010∽0.0024(wt)% respectively. Total amount of the impurity elements O, S, P and H in the steels is 0.0061∽0.0077%. Dominant component of the structure in both casting and as-forged samples is acicular ferrite or bainite.
Solid State Chemistry and the Electron Microscope: an Individual's Journey
Authors: Thomas John Meurig 
Published: July 2020

Abstract
From the late 1960s onwards the author embarked on a series of electron microscopic adventures using progressively more sophisticated techniques which yielded structural information and uncovered physics-chemical phenomena that would have been irretrievable by other methods. Illustrative examples include; (i) proof that photoreactivity and unexpected photoproducts of organic molecular crystals are governed by stacking faults, and that applied stress converts some photostable organic solid to photactive ones; (ii) elucidation of interdependence of photoluminesence and polymorphism in organic crystals; (iii) determination of surface pointdefect-concentration at, and discovery of catalytic channeling by metals in the oxidation of, graphite and molybdenite; (iv) establishing the mechanism of interconversion of “stages” in graphite intercalates, and the discovery of incommensurate guest-hosts-structures (with graphiteiron chloride); (v) rationalization of the structures of the many seemingly unrelated phases of bismuth molybdate catalysts (for oxidation) in terms of a common, defect-fluorite (Bi2O3) archetype;
Fine Structures of Zeolites and Mesoporous Materials
Authors: Terasaki Osamu , Ohsuna Tetsu , Kaneda Mizue , Sakamoto Yasuhiro , Hiraga Kenji , Carlsson Anna , Ryoo Ryong , Alfredsson Viveka , Anderson Michael W 
Published: July 2020

Abstract
Zeolites are crystalline aluminosilicates with frameworks built from corner-sharing TO4- tetrahedra(where T is Si or Al but can also be substituted with P, Ga, Ge, etc.) to produce channels or cavities of molecular dimensions. Owing to these characteristic features, zeolites have attracted much attention not only for catalytic applications but also as containers of confined materials. In most circumstances zeolites can only be synthesized as fine powders, ca. 1 μm, and the additional presence of defects or intergrowths makes structure solution difficult. HREM is therefore one of the most important tools for the investigation of such structures and the early work of Thomas and his group in Cambridge were dedicated to developing such techniques. The advantage of HREM has been subsequently demonstrated especially for characterizing and determining fine structures, e.g. (i) zeolite intergrowths structures such as ERI/OFF and FAU/EMT, (ii) enantiomeric intergrowths of structural units in ETS-10 and structural solution, (iii) surface structures and growth units and (iv) size of clusters and their registry with the framework structures.
Shyntesis and Characterization of Quantum Dot Superlattices
Authors: José-Yacamán M , Gutiérrez-Wing C , Santiago P , Ascencio J , Camacho A 
Published: July 2020

Abstract
The engineering of a new generation of advanced materials based on nanoparticles demands the fabrication of self-assembled arrays of passivated metal, oxide and semiconductor clusters (1 -). In particular the case of self-assembled gold clusters passivated with an organic molecule has attracted the attention of several researchers (2-3). Because its unique properties gold metal is a leading candidate for the fabrication of single electron tunneling devices.
Passivated gold nanoclusters were produced using the method developed by Brust et.al. (4) with the modifications of Whetten et.al (5) n-alkylthiol molecules were used as passivating agent. Carbon chains from C=4 to C=18 were used. It was found that C=12 dodecanethiol was optimum for forming ordered arrays of the clusters. To produce the superlattice crystallization a toluene vapor atmosphere was used. The passivated clusters were deposited on a copper electron microscope grid covered with carbon.
The Nanostructures Of Amorphous Silicas
Authors: Hobbs Linn W , Yuan Xianglong , Qin L C , Pulim Vinay , Coventry Alexander 
Published: July 2020

Abstract
Silicon dioxide is an important catalyst material, a mainstay insulator in microelectronics, and a widely distributed terrestrial and marine skeletal mineral. Geologically, it is found in one of a large number of polymorphic crystalline states, but can also be rendered “amorphous” by rapid cooling from the melt through a glass transition, depositing from a vapor or from solution (in radiolaria skeletons), oxidizing silicon, or irradiating with electrons, ions or neutrons. While the structures of the crystalline polymorphs are well documented, the structure of even the exhaustively studied vitreous silica remains largely enigmatic. Diffraction provides average information about short-range order—which appears to comprise [SiO4] tetrahedral units in all but a high-pressure crystalline polymorph—but is relatively insensitive to alternative medium-range arrangements of these structural units. One sensitive, but little understood, indicator is the position and shape of the first sharp diffraction peak (FSDP).
Aberration Corrected Lattice Imaging With Sub Ångstrom Resolution
Authors: Kisielowski C , Nelson EC , Song C , Kilaas R , Schwartzman A , Thust A 
Published: July 2020

Abstract
In 1999 NCEM's One Ångstrom Microscope (OAM) became fully operational. The OAM is a Philips CM300 FEG/UT field emission microscope with holographic capabilities that is equipped with a Gatan Image Filter (GIF) and operates at 300 kV. It was designed to reach a resolution close to the “magic barrier” around one Ångstrom (100 pm) by combining mid voltage technology with advanced computer processing [1,2]. Ahardware correction of the three-fold astigmatism allows for aberration free imaging down to sub Ångstrom values [3]. In this contribution it will be shown that the instrument's performance exceeded expectations because sub Ångstrom resolution can be achieved by reconstructing electron exit waves from focal series [4].
Figure la depicts a simulated [110] lattice image of a 90° partial dislocation in silicon. Tersoff potentials were used to calculate the exact atomic positions around dislocations with different core structures [5].
Asphaltene Aggregation Studies of Crude Oil Using 3-D Confocal Microscopy
Authors: Johnston Robert J , Mason Thomas G 
Published: July 2020

Abstract
Confocal laser scanning microscopy (CLSM) has been used to generate three dimensional projection maps of less fluorescent domains caused by asphaltene aggregates in the autofluorescent matrix of crude oil. Heavy crude oils contain asphaltene particles resulting in the production of optically observable micron sized asphaltene aggregates. This technique has been employed to determine the volume fraction of aggregated asphaltenes, øagg, and the time evolution of this phenomenon. The measurements cover a range of various concentrations of asphaltene volume fractions of the heavy asphaltenic oil, øm, from øm = 0 to øm = 0.6.
Examining crude oils for asphaltenes aggregates using CLSM presents a challenge due to the strong absorption of the oils. This is because some molecules of the crude oil fluoresce when excited by optical laser light used as a source in the CLSM. Other molecules of the crude oils absorb light at similar wavelengths.
Chemical Compostion Analysis on Sintered Gold and Platinum Nanoparticles
Authors: Lu S , Yao N , Aksay I A 
Published: July 2020

Abstract
Nanoparticles continue to attract interests because they fall into intermediate stage between molecular and macroscopic materials. Due to their large surface-to-volume ratio, nanoparticles exhibit physical and chemical properties that differ markedly from those characterizing the bulk solid state. One example is the phase diagram of a nanomaterial. Because nanocrystals display clear changes in both the thermodynamics and the kinetics of phase transitions, we expect different solubility limits in the nanometer regime. This means that phases unstable or unobserved in extended solids may be prepared as nanocrystals. We synthesized Au and Pt nanoparticles and performed chemical analysis on the sintered agglomerates.
The colloidal Au and Pt particles were synthesized according to Turkevich's method. An aqueous AuCl3 solution (50mg Au/L) was heated to 70°C. A determined amount of lwt% aqueous sodium citrate dihydrate (Na3C6H5O7.2H2O) solution was added such that the citrate-to-Au mass ratio was 10.
In Situ and Ex Situ Microscopic Study of Propylene Polymerization With Heterogeneous Mgcl2-Supported Ziegler-Natta Catalysts
Authors: Oleshko V , Crozier P , Cantrell R , Westwood A 
Published: July 2020

Abstract
The large-scale commercial production of polyolefins by catalytic Ziegler-Natta polymerization have stimulated the development of the third, fourth and fifth generation heterogeneous catalysts comprising high surface area defective MgCl2 with TiCl4, electron donors, and AlR3-co-catalysts. In spite of intensive research over the years, the present level of understanding of the catalysts is still incomplete because of their complex composition leading to a multitude of local active site environments. The aim of this work is to provide a new insight into the process via in situ video microscopy of gas phase propylene polymerization over MgCl2-supported Ziegler-Natta catalysts combined with ex situ characterization by light and electron microscopy techniques (SEM, TEM, HRTEM, STEM, PEELS and windowless EDX). Procedures for catalyst synthesis are described elsewhere. The catalysts were stored in a dry box under a He atmosphere (&lt;lppm H2O/O2). Samples were transferred to specimen holders in the dry box and then transferred into the microscopes under high purge N2 conditions to prevent poisoning of the catalysts by air and moisture.
Image Reconstruction From TEM Diffraction Patterns Using Feinup Algorithm
Authors: Chen Q , Weierstall U , Spence J C H 
Published: July 2020

Abstract
Iterative algorithms, which use diffracted intensities and some a-priori knowledge of an image to solve the phase problem, have been under development for many years. The promised super-resolution images, reconstructed from diffraction information alone, would be of the greatest value for molecular imaging and for the image of nonperiodic structures in materials. Using simulated data it is possible, for example, to reconstruct a complex object from a knowledge of its diffracted intensities with certain known support functions. Some success has recently been achieved reconstructing micrometer-sized non-periodic objects using coherent X-rays by the Feinup method. One favorable support function consists of two holes spanned by the coherence width of the beam, with one or both holes containing an unknown object. Our simulations, which iterate between diffracted intensities and the image, applying the known support (either completely opaque or completely transparent) and intensities in each domain, confirm that image reconstruction is possible for loose supports and noiseless data.
In-Situ Characterization of Carbon Nanotube-Polystyrene Composite Deformation
Authors: Qian D , Dickey E C , Andrews R , Rantell T , Safadi B 
Published: July 2020

Abstract
Carbon nanotubes (NTs) have novel electronic properties and exceptionally high Young's moduli on the order of TPa. so NTs have potential applications in advanced composite materials such as conductive polymers, electromagnetic-radio frequency interference (EMI/RFI) shielding material and opto-electronic materials. The utility of the nanotubes in composite applications depends strongly on the ability to disperse the NTs homogeneously throughout the matrix without destroying the integrity of the NTs. Furthermore, interfacial bonding between the NT and matrix is necessary to achieve load transfer across the interface, which is desirable for improving the mechanical properties of polymer composites.
In this work, aligned multiwalled carbon nanotubes (MWNTs) produced by continuous chemical vapor deposition (CVD) (see Fig.l), were homogeneously dispersed in polystyrene (PS) matrices by a simple solution-evaporation method. Using this procedure, we made uniform MWNT-PS composite films ∼0.4mm thick for ex-situ mechanical tensile test and very thin films, ∼100nm, for in-situ TEM tests, as shown in Fig.2.
CBED Study of Mn3+ Orbital Ordering in LaMnO3
Authors: Jiang B , Zuo JM , Chen Q , Cheong S-W , Spence JCH 
Published: July 2020

Abstract
Mn oxides of pervoskite-related structure containing Mn ions have attracted considerable interest due to the colossal magnetoresistence (CMR) effect. Doping the family of compounds La1-x Cax MnO3 with divalent Ca ion oxidizes Mn+3 to Mn4+, introducing holes in the 3d bond orbital that give rise to a series of interesting physical properties. The parent compound LaMnO3 (Pbnm) with unit cell of a=5.5367Å b=5.7473Å and c=7.6929Å, is an antiferromagnetic insulator in which orbital ordering is established due to the cooperative Jahn-Teller (JT) effect breaking the degeneracy of the electronic configuration of Mn3+ (t2g3eg1). This particular C-type orbital ordering is responsible for the A-type magnetic structure observed by Wollen and Kohler. Theoretical Monte-Carlo simulation has shown that the A-type antiferromagnetic state is stable in a model based on JT phonons, using coupling values physically reasonable for LaMnO3 and considering the small but important effect of octahedral tilting.
As-Quenched ARC Products By bulse - Discharge
Authors: Murooka Y , Maede Y , Ozaki M , Hibino M 
Published: July 2020

Abstract
Since their discovery, steady state arc discharge has been used for fullerenes and nanotubes production. Unfortunately this method intrinsically made it difficult to understand their growth mechanisms since the discharge included many complicated physical processes and the growth happened in the non-equilibrium arc plasma. Processes such as heating of the cathode by cation bombardment, emission of thermal electrons, and heating of the anode by electron bombardment are important in order to follow the mechanism, but it is difficult to study them separately. In the present work, however, it was shown that a pulse-arc discharge with a small current for a short time could simplify the discharge process and provide as-quenched arc products, which should be useful to understand the mechanisms.
Short discharges with a small current were performed on the pulse-arc system, which was developed by the authors.
One, Two, and Three Demisional Gold Nanoparticle Arrays from Reverse Micelles
Authors: Zhou WL , Lin J , O'Connor CJ 
Published: July 2020

Abstract
Nanoparticles (1-100 nm) of semiconductors and metals have shown some unique optical, electric and magnetic and catalytic properties which are greatly different from their bulk materials. Recently the use of these nanoparticles as quantum dots in nanoelectronics requires their arrangement in one, two, and three dimensions (1D, 2D and 3D). Therefore more attention has been paid to the organization of these nanoparticles into ordered arrays in order to achieve novel collective properties. Gold colloids have been well studied for its self-organization in several systems. Here we present 1D, 2D and 3D gold self-organization nanostructure generated from reverse micelles (microemulsion system).
Gold nanoparticles were prepared by the reduction of HAuCU in CTAB (cetyltrimethylammonium bromide)/Octane+l-Butanol/H2O microemusion system using NaBH4 as the reducing agent. Typically, 0.3g of CTAB, 0.148ml of 0.056M HAuCl4 aqueous solution, l.Og octane (surfactant) and 0.25g 1-butanol (cosurfactant) were mixed together and stirred vigorously for 10 min until a homogenous phase was obtained.
SEM and TEM of Metallic Inverse Opals
Authors: Blanford CF , Yan HW , Stein A , Carter CB 
Published: July 2020

Abstract
Drawing on nature, synthetic opals (e.g., gilsonite) consist of uniformly sized ceramic spheres ordered into large close-packed domains. In order to improve the toughness or appearance of these chemically bonded ceramics, a polymer is often infiltrated into the interconnected space between the packed spheres. In a similar fashion, colloidal crystal arrays of submicrometer silica or polymer spheres have been employed as templates for periodic porous solids. All the methods for preparing periodic macroporous materials share a common synthetic thread: first, the colloidal crystals are formed from monodisperse spheres; next, the void spaces are filled and solidified; finally, the template is removed by heat, by refluxing in a solvent such as THF (in the case of polymer spheres), or by soaking in hydrofluoric acid (in the case of silica spheres). The product, which can be thought of as an “inverse opal,” often exhibits the same iridescence as a natural opal due to the similarity between the periodicity of the wall structure and the wavelength of light.
Calcium Release and Spread Within the Sarcomere of Vertebrate Skeletal Muscle Fibers.
Authors: Baylor Stephen M , Hollingworth Stephen 
Published: July 2020

Abstract
Experiments were carried out to investigate excitation-contraction coupling in vertebrate skeletal muscle fibers. Single-dissected twitch fibers of frog muscle were injected with flourescent calcium (Ca) indicators, and fluorescence intensity (F) and changes in intensity (ΔF) were recorded during various stimulation protocols (16-22 °C). In fibers activated by an action potential, the low-affinity indicator furaptra was used to estimate the spatially-averaged change in myoplasmic free calcium concentration (ΔC[a]; peak value, 15-20 μM; time to peak, 4-5 ms). Δ[Ca], in combination with a kinetic model, was used to calculate the change in concentration of calcium bound to the principal myoplasmic Ca buffers (ATP, troponin, parvalbumin). The rate of Ca release from the sarcoplasmic reticulum (SR) was obtained from the time derivative of the estimated change in total myoplasmic calcium concentration, Δ[CaT] (= Δ[Ca] + Δ[CaATP] + Δ[CaTroponin] + Δ[CaParvalbumin]).
New Projects for Superstem
Authors: Brown L M , Bleloch A L 
Published: July 2020

Abstract
It is proposed to build two high-performance general-user instruments at Daresbury, Cheshire, where the present U.K. synchrotron facility is located. The instruments can be used on-site, where accommodation for visitors is already available. They can also be used remotely, via the internet. The features of the instruments are: aberration-corrected optics, voltage-stabilised electron spectrometer, and multi-specimen stages to facilitate rapid throughput of routine work. We anticipate that a sub-Angstrom probe size will be available for incoherent HAADF imaging, and PEELS with an energy resolution better than 0.3V for losses up to 2kV. The operating voltage will be l00kV.
The new instruments will allow better analysis of continuing problems. Anticipated developments are as follows:
1. Study of helium bubbles in reactor materials: Recently, accurate quantification of helium has been achieved and a quantitative explanation has been given for the ‘blue shift’, that is, the increasing threshold energy for the Is to 2p transition due to quantum confinement of the excited state with increasing gas pressure.
Electron Scattering with an Atomic Sized Probe
Authors: Silcox J 
Published: July 2020

Abstract
It is the presence of local variations in atomic and electronic structure that often gives rise to intriguing properties of materials. Control of material properties then rests on detection of the local variations in the materials, determination of the origin of those variations and then understanding how such variations can be controlled to achieve a desired functionality. Recent examples using STEM with an atomic sized probe (∼2.2 Å) include studies of the bonding at grain boundaries in nickel rich Ni3Al doped with boron. EELS measurements revealed changes in the d-hole density-of-states that were used to estimate changes in the electronic contribution to the grain boundary energy. These changes in grain boundary strength correlated with a change in fracture from an intra- to an inter-granular mode. In another example, the observation of metal induced gap states at Cu/MgO interfaces provided evidence that the dipole moment across that interface was relatively low.
Non-Stoichiometry at Tilt Grain Boundaries in SrTiO3
Authors: Duscher G , Kim M , Browning N D , Pantelides S T , Pennycook S J 
Published: July 2020

Abstract
The origin of electrically active grain boundaries in perovskite oxides and related materials remains controversial. The stoichiometry of the grain boundary core structure and the role of oxygen vacancies are the key issues involved. Previous results have given no indications of any non-stoichiometry at SrTiO3 grain boundaries, despite the fact that SrTiO3 is the system where atomic column EELS resolution has been demonstrated [1], and where atomic resolution images of the core structures have been obtained by Z-contrast imaging [2,3]. Here we show EELS spectra from individual dislocation cores in an 8° [100] tilt grain boundary in SrTiO3 that show significant oxygen depletion.
The low angle grain boundary with well-separated dislocation cores makes it possible to study individual cores with high energy resolution in EELS. Previous work either averaged over all structural units in the grain boundary, sacrificing spatial resolution [2,3], or, used a very low probe current to obtain the highest spatial resolution [1].