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The conventional X-ray diffraction (XRD) methods probe for the presence of long-range order towards a solution of theaveragecrystal structure. Experimentally, structural information about long-range, periodic atomic ordering is reflected in the Bragg scattering while local atomic structural deviations from the average structure mainly affect the diffuse scattering intensities. In order to obtain structural information about both average and local atomic structures, a technique that takes in account both Bragg and diffuse scattering needs to be employed, such as the total scattering atomic pair distribution function (PDF) technique. This article introduces a PDF-based methodology that can be applied to extract precise structural information about nanoparticles such as the size of the crystalline core region, the degree of crystallinity, the atomic structure of the core region, local bonding, and the degree of the internal disorder, as a function of the nanoparticle diameter. This article sheds light on a new PDF-based methodology that can yield precise quantitative structural information about small nanocrystals from XRD data, and also describes the essential aspects of this proposed methodology as well as its great potential. This method is generally applicable to the characterisation of the nanoscale solid, many of which may exhibit complex disordered structure. [ABSTRACT FROM AUTHOR]

The approach of the atomic pair distribution function (PDF) technique to determine the atomic-scale structure of nanocrystalline materials is introduced and illustrated with results of studies on V 2 O 5 nanotubes and clusters of Cs atoms intercalated inside the pores of the zeolite ITQ-4. We find that V 2 O 5 nanotubes are built of double layers of V-O 5 and V-O 4 units. Inside the channels in ITQ-4 Cs atoms are found to assemble in short-range ordered zigzag chains. [ABSTRACT FROM AUTHOR]

Raney Pd and Rh fine particles were prepared from decagonal Al75Pd25 and Al9Rh2 with an Al9Co2-type structure, respectively, by leaching with NaOH aqueous solution. The atomic pair distribution functions (PDFs) for the Raney Pd and Rh fine particles indicate structural features similar to an fcc structure, suggesting atomic rearrangement toward the closest packing of constituents during the leaching process. Transmission electron micrographs indicate that Raney Pd and Rh are aggregates of fcc-structured nano-crystallites with a diameter of 5-6 nm. [ABSTRACT FROM AUTHOR]

Strontium doped bismuth ferrite is prepared by the customary solid-state route. Rietveld refinement analysis using GSAS – II shows that the X-ray diffraction pattern crystallizes in Pm-3m phase. Maximum entropy method (MEM) is used to fabricate the electron density mapping to determine the type of bonding between Fe - O and Bi/Sr - O ions in Bi0.6Sr0.4FeO3 system. The localized structure deviating the long-range ordering of Bi0.6Sr0.4FeO3 is analyzed using atomic pair distribution function (PDF). The interaction between the chemical bonding and the magnetoelectric effect is unveiled using crystal chemistry method. [ABSTRACT FROM AUTHOR]

The real-space total scattering atomic Pair Distribution Function (PDF) method has been used to study the effect of temperature (T) on the structural features of the manganite N d 0.5 S r 0.5 M n O 3 . The powder X-ray diffraction data were collected as a function of T ranging from 92 to 300 K. The PDF data were analyzed at a Q max value of 28 Å − 1 and a room temperature model was used for the refinement of the data at two different refinement ranges (r-ranges): 1.7–10 and 1.7–30 Å for all the temperatures. Good agreements between the model and the PDF data were obtained with good agreement factor ( R w ) values and a possible evidence for a structural phase transition (mainly from an orthorhombic Imma to a monoclinic P 2 1 / m phase) was observed at T = 145 K through the variation of the lattice parameters a, b, and c, and of R w as T decreases. [ABSTRACT FROM AUTHOR]

High-energy X-ray diffraction study was performed on lead titanate (PbTiO3). Short-range order structure was revealed using atomic pair-distribution function (PDF) method. In the high-temperature cubic phase, there is a large deviation between local and average structure. Especially, Pb atoms deviated from the cubic lattice framework, but establish Pb-O-Pb random network. [ABSTRACT FROM AUTHOR]

The local structure of apatite-type lanthanum silicates of general formula La9.33+x(SiO4)6O2+3x/2 has been investigated by combining the atomic pair distribution function (PDF) method, conventional X-ray and neutron powder diffraction (NPD) data and density functional theory (DFT) calculations. DFT was used to build structure models with stable positions of excess oxide ions within the conduction channel. Two stable interstitial positions were obtained in accordance with literature, the first one located at the very periphery of the conduction channel, neighbouring the SiO4 tetrahedral units, and the second one closer to the channel axis. The corresponding PDFs and average structures were then calculated and tested against experimental PDFs obtained by X-ray total scattering and NPD Rietveld refinements results gathered from literature. It was shown that of the two stable interstitial positions obtained with DFT only the second one located within the channel is consistent with experimental data. This result consolidates one of the two main conduction mechanisms along the c-axis reported in the literature, namely the one involving cooperative movement of O4 and Oi ions. [ABSTRACT FROM AUTHOR]

The atomic-scale structure of Ti-related perovskite materials, ATiO3(A= Sr, Ba, Pb), has been studied using high-energy X-ray diffraction, Rietveld refinement, and the atomic pair-distribution function technique. It was found that the local structures of BaTiO3and PbTiO3deviate from their average structures. We also found the tetragonal distortion in their middle-range-order structures (∼ 7 Å). The temperature dependence of the middle-range-order structures showed that an order-disorder character exists in BaTiO3and a displacive-type character exists in PbTiO3. [ABSTRACT FROM AUTHOR]

The local structure of any condensed matter is accessible via an atomic pair distribution function (PDF) analysis. Here, the local atomic structure of the well-ordered face-centred icosahedral (fci)-Mg 25 Y 11 Zn 64 , fci-Ho 9 Mg 26 Zn 65 and simple icosahedral Ho 11 Mg 15 Zn 74 quasicrystals have been investigated by PDFs obtained from in-house X-ray and synchrotron powder data. Least-squares refinements using periodic 1/1 and 2/1 approximants as models for the local atomic structure have been performed. They reveal predominantly Frank–Kasper-type coordination polyhedra. The basic building block is a Bergman cluster of about 100 atoms of 14?Å diameter. RE 8 cubes of edge length 5.4?Å are part of the cluster occupying pentagon dodecahedral positions. The cluster connection scheme follows in general that of Henley's canonical cell tiling. However, according to our results, overlapping clusters are likely to be present in the quasicrystalline structure. Thus interpenetration seems to be a general feature for clusters in quasicrystals, which complicates the ongoing discussion on their nature. [ABSTRACT FROM AUTHOR]

MXenes are recently advanced two-dimensional layered nanomaterials that have various characteristic properties for developing electrochemical sensors for bioanalytical applications, such as hydrophilicity, good biocompatibility, electrical conductivity, heightened ion transportation, and ease of functionalization. MXenes are revealed to be having applications in various other fields including energy storage, and catalysis. The combination of a layered structure, biocompatibility, and high surface functionalities makes MXene a highly versatile material for electrochemical sensing applications. The effect of various synthesis and functionalization strategies on tuning the properties of MXenes toward improving sensing abilities has been comprehensively discussed. This review article also discusses the relevance of early diagnosis of various biomarkers of chronic diseases via MXene modified electrochemical sensor for gaining a better understanding of their early diagnosis, disease progression, and risk assessment. Modification with MXenes improves the electrocatalytic functionality of the electrodes thereby improving their applicability in health and biomedical fields. [ABSTRACT FROM AUTHOR]

BaTiO3-based materials are used as the replacement for lead-based perovskite materials for its wide dielectric applications. But the substitution of different doping elements in pure BaTiO3 drastically affects the microstructure, phase transition behavior and electrical properties. In the present work, local structure, phase transformation and dielectric behavior of BaCexTi1-xO3 (BCT) ceramics were studied for compositions x = 0.02, 0.05 and 0.1. A diffuse phase transition from orthorhombic to cubic via tetragonal in BCT with increasing Ce content was observed. An increase in particle size with Ce doping concentration was observed in FESEM images. Spherical and cuboid-shaped particle in the order of 80–150 nm was observed in transmission electron microscopic (TEM) images. RAMAN spectra confirm the tetragonal to cubic phase transition. Local structural and phase transformation behavior was obtained from laboratory-based PDF and XRD, respectively. Change in PDF was observed due to an increase in Ce doping. Dielectric properties decreased for Ce mole fraction of x = 0.1. [ABSTRACT FROM AUTHOR]

We performed local structure analyses of relaxor ferroelectric of lead magnesium niobate (PMN) by combining an extended X-ray absorption fine structure (EXAFS) and atomic pair-distribution function (PDF) methods. EXAFS study revealed that Pb atoms of PMN are disordered largely compared with those of PbTiO3, though the local environment of the Nb atoms is not significantly different from that for NaNbO3and AgNbO3. The PDF analysis also revealed the short-range order structure of Pb, which is deviated from the perovskite framework. [ABSTRACT FROM PUBLISHER]

Limestone Calcined Clay Cements, LC3, allows CO2 emissions savings up to 40%. The resulting binders have competitive mechanical performances after a week. However, the reactivity of LC3 at early ages is slow and should be improved. Here, we use a multitechnique approach to help in the understanding of early age reactivities which were measured by calorimetry, Frattini assay, and mechanical strengths. The disorder in the kaolinites was quantified by powder diffraction. Some footprints of the local disorder in the resulting metakaolin have been investigated by synchrotron pair distribution function (sPDF). It is concluded that Al-O interatomic correlation position and intensity in the sPDF of the calcined kaolinitic clays could be an additional good descriptor to follow early age reactivity. The results were complemented by 27Al MAS-NMR studies. The rate of the pozzolanic reaction at early ages is governed by the particle size, surface area, and local disorder of metakaolin. [ABSTRACT FROM AUTHOR]

MXene, a novel class of 2-dimensional transition metal carbides has evolved as a promising material for various applications owing to its outstanding characteristics such as hydrophilicity, high electrical conductivity, surface area, and attractive topological structure. MXenes can form dispersion in common solvents and constitute composite with other nanomaterials, which can be utilized as effective transducers for molecular sensing. MXene-modified support materials, thus provide an intriguing platform for immobilization of target molecules onto their surface. The literature reveals that it has been increasingly utilized in the sensing of diverse types of analytes including glucose, pharmaceuticals, metals and dyes, cancer markers, pesticides, neurotransmitters, small valuable molecules, and so on. In this review, we summarize the recent updates in the MXene modified materials for sensing. For the convenience of our audience, we have distributed the analytes into categories and discussed them comprehensively. Not only we present the synthesis approach, electrochemical properties and surface chemistry of MXenes but also discussed briefly the current challenges and an outlook for future research in the related area. [ABSTRACT FROM AUTHOR]

This paper elucidates recently emerging trends in fabrication of conducting polymers (CP)/MXene (MX) hybrid nanoarchitectures for energy storage electrodes/gadgets. Special emphasis is given to recently emerging trends in MX/polyaniline (PAN), MX/polypyrrole (PPy), and MX/Poly (3, 4-ethylenedioxythiophene) polystyrene sulfonate (PEDOT: PSS) nanoarchitectures for energy storage applications. Further insight is given to the emerging horizons and challenges confronting these gadgets for efficient energy storage functions, in addition to the prospects of boosting their performances, for outstanding energy storage applications [ABSTRACT FROM AUTHOR]

The diffuse scattering signal of amorphous or liquid systems contains information on the local atomic structure, and this can be related to the density, compressibility, thermal expansion and other thermoelastic properties. However, the analysis and full exploitation of the diffuse scattering signal, in particular for systems under extreme conditions of high pressures and temperatures are difficult to handle. Amorpheus is a Python-based software allowing the determination of the structure factor and the radial distribution function of amorphous and liquid systems. Based on previously reported methodologies, Amorpheus stands out for the implementation of automatic algorithms allowing the user to choose the most suitable parameters for the data treatment and making possible systematic analysis of datasets collected in experiments carried out in Paris-Edinburgh press, multi-anvil apparatus or diamond anvil cell. [ABSTRACT FROM AUTHOR]

A total scattering neutron instrument is simulated using a ray-tracing package to evaluate the technique and data reduction algorithms. The neutron guide and chopper system were first optimized to obtain the highest neutron flux with satisfactory angular divergence. Next, a series of virtual experiments were conducted using heavy water and calibration vanadium samples. Data analysis algorithms were also developed. The resultant simulated sample static structure factor was in excellent agreement with the experimental measurements. Additionally, analytical and Monte Carlo methods are applied to account for multiple scattering in a variety of sample sizes. The effectiveness of this method and possible improvements are discussed. [ABSTRACT FROM AUTHOR]

The structural properties of water confined in two silica matrices characterised by well-controlled organised porosity with a narrow pore size distribution: i) a new mesoporous bioactive glass (MBG 92S6) and ii)SiO2 MCM-41 were studied using laboratory total X-ray scattering coupled to molecular pair distribution function (PDF). The PDF analysis shows that the hydrophilic/hydrophobic character of the water-bioglass interface affects the structural properties of the confined water in the same way as water confined in different mesoporous matrices presenting an intermediate hydrophilic and hydrophobic interface regardless of their pore size and distribution. We also compare the effect of the confinement inside MBG 92S6 and different mesoporous hydrophilic and hydrophobic silica matrices. We show that the pore surface properties have a stronger influence on the structural organisation of the confined water than the pore size distribution. [ABSTRACT FROM AUTHOR]

The article discusses the highlights of the workshop entitled "Advanced Simulation Techniques for Total Scattering Data," held in Santa Fe, New Mexico on October 16-19, 2012, for integrating total energy simulation techniques in experimental atomic pair distribution function (PGF) data modeling. Hsiu-Wen Wang of Oak Ridge National Laboratory discussed experimental work that explore the surface hydration of SnO2 nanoparticles.

This article deals with the structural and optical properties of zinc oxide and zinc sulfide nanoparticles synthesized by chemical precipitation method. X-ray diffraction study confirmed the wurtzite structure of zinc oxide and the cubic structure of zinc sulfide. The average crystallite size, the lattice constant, and unit cell volume were calculated from the x-ray diffraction study. The ultraviolet-visible absorption spectra and the Tauc's plot were confirmed the energy gap of zinc sulfide and zinc oxide samples to be 5.1 eV and 3.73 eV, respectively. Fourier Transformation Infrared spectra confirmed the formation of zinc oxide and zinc sulfide through the appearance of peaks between 618 cm−1- 439 cm−1. The photoluminescence spectra confirmed the violet emission from ZnO and UV from ZnS. The transmission electron microscope study also confirmed the existence of particles in nanometer size. Composition analysis confirmed the existence of zinc, sulfur, and oxygen. The vibrating sample magnetometer results depict that the zinc sulfide and zinc oxides are ferromagnetic at room temperature. Electron paramagnetic resonance spectra also confirmed the ferromagnetic nature of zinc sulfide and zinc oxide samples. [ABSTRACT FROM AUTHOR]

CdTe nanoparticles capped with a cationic thiolate ligand were stably dispersed in ionic liquids, 1-alkyl-1-methyl-pyrrolidinium bis(trifluoromethanesulfonyl)amides with an alkyl group of n-propyl, butyl and octyl-chain, and in an ionic plastic crystal, 1-ethyl-1-methylpyrrolidinium bis(trifluoromethanesulfonyl)amide. Dispersion behavior of CdTe nanoparticles in these ionic media was evaluated, in which the solvation of nanoparticles by the ionic components was particularly interested. The ionic media showed alkyl-chain length-dependent solvation behavior, which was suggested by the thermal analysis of nanocomposites. The longer alkyl-chains led to the greater decrease in the thermal melting enthalpy of ionic media with the introduction of nanoparticles. The ionic liquid with an octyl-chain, which is considered to form a thicker solvation layer, afforded better emission durability of CdTe nanoparticles compared to the ionic liquid with a shorter alkyl chain. [ABSTRACT FROM AUTHOR]

Neutron diffraction studies were performed on xSrO-(100-x)TeO2 (x = 5, 7.5 and 10 mol%) glass, anti-glass and crystalline samples. For the structural modeling, Fourier transformation, Reverse Monte Carlo (RMC) simulations and Rietveld refinement were used. The pair distribution functions show the nearest neighbor peaks of Sr—O, Te—O and O—O correlations at 2.64, 1.95 and 2.70 Å, respectively. RMC analysis was used to determine the partial pair distributions, cation-oxygen bond lengths, co-ordination numbers and three-particle bond-angle distributions. The glass sample with 7.5 mol% SrO was transformed into the anti-glass phases by annealing at 350°C and into the crystalline phases by annealing of the anti-glass sample at 450°C. The crystal structure parameters of the anti-glass and crystalline samples were determined by Rietveld analysis and it was found that the anti-glass sample contains disordered SrTe5O11 and SrTeO3 phases, while the crystalline sample contains monoclinic SrTeO3 and orthorhombic TeO2 phases. [ABSTRACT FROM AUTHOR]

The importance of total scattering and its Fourier transform, the pair distribution function, in crystallography was understood soon after it was shown that crystals diffract X-rays. However for the next fifty years or so other techniques based more firmly on the crystal lattice came to the fore and total scattering measurements were largely the domain of those studying liquid and amorphous structure. In the late 1980s it was 'rediscovered' as a way to uncover disorder within crystal structures and since then the combination of improved instrumentation and analysis has led to a resurgence of the total scattering method. This review sets out this journey, highlighting both the early origins and – more importantly – the ways that total scattering and pair distribution functions are routinely used within crystallography today. [ABSTRACT FROM AUTHOR]

Non-centrosymmetric to centrosymmetric structural transformation of BaZrxTi1−xO3 (x = 0, 0.05, 0.1, 0.3) as prepared by soilid state reaction was investigated from X-ray diffraction (XRD), X-ray photoelectron spectroscopy (XPS), pair distribution function (PDF) and Raman spectra. Tetragonal BaTiO3 transformed to orthorhombic phase for lower Zr concentration (x = 0.05) and changed to tetragonal to cubic with increasing Zr concentration at room temperature. Dielectric constant changed with the addition of Zr due to the change in local atomic arrangement and achieved highest value 1444 for mole fraction x = 0.1. Change occurred in the intensity for the first Ti–O pair in the PDF pattern due to the incorporation Zr in barium titanate lattice. An extra shoulder due to addition of Zr for the cubic phase of BZT has appeared at 5.64 Å in the PDF pattern. Structural and electrical properties of BZT were influenced by additions of Zr due to the change in local atomic arrangement. [ABSTRACT FROM AUTHOR]

Hydrous ruthenium dioxide, RuO2·xH2O, is a material of active investigation as an electrode material for supercapacitors. A combination of elastic and inelastic neutron scattering together with thermal gravimetric studies and DFT calculations have provided new insight into the nature of the surface species present on RuO2·xH2O. Our results confirm that hydrous ruthenium oxide is a nanocrystalline material consisting of a core of RuO2. We show that the surface consists largely of Ru–OH with small amounts of water hydrogen-bonded to the surface. The hydroxyls are stable up to ∼200°C, i.e. over the composition range x = 0.2–2. The optimal supercapacitor material has x = 0.5–0.7, and in this range, the surface is fully hydroxylated. This provides a route for the proton transport: a proton can attach to a surface hydroxyl to generate coordinated water, proton transport then occurs along the hydrogen-bonded chain by a Grotthuss mechanism. [ABSTRACT FROM AUTHOR]

A time-of-flight neutron total scattering instrument for the China Spallation Neutron Source (CSNS) was designed. The instrument is designed for disordered macromolecular systems with characteristic lengths below 10 nm. The coupled hydrogen moderator of CSNS was selected to ensure the favorable statistics at the smallest scattering vector of 0.01 Å−1. The optics and geometry of the instrument were optimized to cover a wide range of scattering vectors from 0.01 to 70 Å−1. The performance of the instrument was examined using a series of Monte Carlo simulations, which demonstrate that the flux on the sample, the resolution, and the range of the scattering vectors are comparable to those of other advanced neutron total instruments. Finally, a virtual experiment was performed with silica powder. The resulting scattering pattern is consistent with both the numeric calculation and the estimated resolution of the instrument. The designed total scattering instrument at CSNS allows the simultaneous observation of both atomic and nanometer scale structures, having the potential to become a powerful tool for studying the structure of disordered materials in the fields of polymers, biology, and condensed matter physics. [ABSTRACT FROM AUTHOR]

Core-shell structure nanocomposites have been of interest, as they can exhibit unique properties arising from the combination of peculiar characteristics of each component. In this research, core-shell structured nanocomposites, comprising barium titanate (BaTiO3; BT) nanoparticles as the core and titanate (TiO2) nanosheets as the shell, were prepared. The surface of barium titanate (BT) nanoparticles was modified chemically by hydrogen peroxide (H2O2) to create hydroxyl groups. TiO2 nanosheets were deposited on the surface of the functionalized BT core, via alternate adsorption with oppositely charged polyelectrolyte poly(diallyl dimethylammonium) (PDDA) cations to produce an ultrathin TiO2 shell layer that encapsulates BaTiO3 nanoparticles. The structure of the core-shell particles was investigated in order to illustrate their formation mechanisms. Furthermore, this work reported the advance in utilizing a core-shell nanostructure to enhance relative permittivity and maintaining a low loss of polymer nanocomposites. A significant improvement in relative permittivity is attributed to the TiO2 shell, which acts as polarizable dipoles and consequently enhances interfacial polarization. The results indicated that the structure of core-shell nanocomposites is attractive as a novel structural building block for fabricating novel materials and electronic devices. [ABSTRACT FROM AUTHOR]

High-pressure torsion (HPT) is widely used as a severe plastic deformation technique to create ultrafine-grained structures with promising mechanical and functional properties. Since 2007, the method has been employed to enhance the hydrogenation kinetics in different Mg-based hydrogen storage materials. Recent studies showed that the method is effective not only for increasing the hydrogenation kinetics but also for improving the hydrogenation activity, for enhancing the air resistivity and more importantly for synthesizing new nanostructured hydrogen storage materials with high densities of lattice defects. This manuscript reviews some major findings on the impact of HPT process on the hydrogen storage performance of different titanium-based and magnesium-based materials. [ABSTRACT FROM AUTHOR]

In order to study chemical complexity-induced lattice distortion in high-entropy alloys, the static Debye-Waller (D-W) factor of NiCoFeMnCr solid solution alloy is measured with low temperature neutron diffraction, ambient X-ray diffraction, and total scattering methods. The static atomic displacement parameter of the multi-element component alloy at 0 K is 0.035-0.041 Å, which is obvious larger than that of element Ni (~ 0 Å). The atomic pair distance between individual atoms in the alloy investigated with extended X-ray absorption fine structure (EXAFS) measurements indicates thatMn has a slightly larger bond distance (~0.4%) with neighbor atoms than that of others. [ABSTRACT FROM AUTHOR]

The Correlated Debye model for the mean square relative displacement of atoms in near-neighbour coordination shells has been extended to include the effect of finite crystal size. This correctly explains the increase in Debye-Waller coefficient observed for metal nanocrystals. A good match with Molecular Dynamics simulations of Pd nanocrystals is obtained if, in addition to the phonon confinement effect of the finite domain size, proper consideration is also given to the static disorder component caused by the undercoordination of surface atoms. The new model, which addresses the analysis of the Pair Distribution Function and powder diffraction data collected at different temperatures, was preliminarily tested on recently published experimental data on nanocrystalline Pt powders. [ABSTRACT FROM AUTHOR]

High-pressure torsion (HPT) is widely used as a severe plastic deformation technique to create ultrafine-grained structures with promising mechanical and functional properties. Since 2007, the method has been employed to enhance the hydrogenation kinetics in different Mg-based hydrogen storage materials. Recent studies showed that the method is effective not only for increasing the hydrogenation kinetics but also for improving the hydrogenation activity, for enhancing the air resistivity and more importantly for synthesizing new nanostructured hydrogen storage materials with high densities of lattice defects. This manuscript reviews some major findings on the impact of HPT process on the hydrogen storage performance of different titanium-based and magnesium-based materials. [ABSTRACT FROM AUTHOR]

Pressure and temperature dependence of the structure of liquid Sn has been measured up to 5.3 GPa and 1373 K using multi-angle energy-dispersive X-ray diffraction in Paris–Edinburgh cell. Under nearly isobar condition at ∼1 GPa, liquid Sn displays a normal behavior with gradual structural changes with temperature up to 1373 K. Under isothermal compressions at 850 and 1373 K, however, the structure factors of liquid Sn both show a turn-over at ∼3 GPa in the height of the first diffraction peak. According to the hard sphere cluster model, the structure of liquid Sn may be viewed as two different types of clusters. Below ∼3 GPa, it is shown that the packing fraction of the dominant cluster (occupying ∼0.94 fraction) changes with compression, while above ∼3 GPa, the packing fractions and the hard sphere diameters of both clusters start to influence the structure, causing significant changes with increasing pressure. Our results suggest that the compression behavior of liquid Sn changes from localized densification only in one cluster below ∼3 GPa to homogeneous structural changes in both clusters above ∼3 GPa. [ABSTRACT FROM AUTHOR]

The article offers information on several and applications and developments of pair distribution function (PDF) and total scattering analysis to novel complex materials. Topics include obtaining total scattering structure function from a powder diffraction pattern, utilization of novel experimental setups like high flux-high data throughput neutron instruments and image-plate detector coupled with high energy synchrotron x-ray radiation, and understanding of conventional bulk materials.

This article provides, in tutorial style, a review of X-ray scattering methods commonly used to characterise nanoparticles and gives numerous case studies of basic science and industrial applications right up to the present. It is divided into two major sections, broadly covering X-ray diffraction and small-angle X-ray scattering. Each section begins with a brief introduction to the technique and the information that can be obtained by using it, followed by a discussion on experimental considerations, with a particular focus on nanoparticle characterisation. The techniques and analysis methods are demonstrated by way of examples of a wide variety of nanoparticle materials and synthesis methods. Recent advances in related techniques such as anomalous scattering and pair distribution function analysis are also described and discussed. [ABSTRACT FROM PUBLISHER]

The article announces the winners of the 2014 Neutron Scattering Society of America (NSSA) prizes, including neutron scattering researchers Sunil K. Sinha, Emil Bozin, and Kate A. Ross.

In situ synchrotron X-ray measurements were performed on the isothermal annealed Zr48Cu36Al8Ag8 bulk metallic glass (BMG). The crystallisation behaviour and structural evolution during the isothermal annealing were investigated by pair distribution function (PDF) analyses. The results indicate that the crystallization behaviour of the samples annealing at 743 K can be well described by the PDF data. The crystallisation process starts from 12 min and finishes at 54 min, with a rapid transforming period within 24–42 min. Dramatic structural changes take place in short, medium and long atomic range during crystallization. It is found that atoms closely pack in short range, while loosely pack in medium range, indicating the short and medium range ordering in BMG. Furthermore, atoms pack more and more closely during crystallisation process, and finally form the closely packing shells. [ABSTRACT FROM AUTHOR]

Most materials expand upon heating. However, although rare, some materials contract upon heating. Such negative thermal expansion (NTE) materials have enormous industrial merit because they can control the thermal expansion of materials. Recent progress in materials research enables us to obtain materials exhibiting negative coefficients of linear thermal expansion over -30 ppmK-1. Such giant NTE is opening a new phase of control of thermal expansion in composites. Specifically examining practical aspects, this review briefly summarizes materials and mechanisms of NTE as well as composites containing NTE materials, based mainly on activities of the last decade. [ABSTRACT FROM AUTHOR]

To set the context for the annual CHESS Users Meeting, it is useful to recall the history of CHESS as a synchrotron radiation facility. It started operating 29 years ago as a parasitic source and one of the first hard X-ray sources. As of the past year, the high energy physics program of experimental data collection at CESR (the Cornell Electron-positron Storage Ring) is over. However, the ring still operates with two beams, electrons and positrons, serving both CHESS and R&D for a future international linear collider. Embedded beneath the central campus of Cornell University, and deliberately preserving an atmosphere responsive to special requests and unusual ideas, CHESS attracts scientists with innovative research programs who need hardware flexibility and attentive technical support, sometimes on very short notice. This highlights the three missions of the Wilson Synchrotron Laboratory complex, and its distinctions as a university-based laboratory: (1) user X-ray service; (2) training of accelerator physicists and beamline scientists; and (3) a laboratory for new techniques and instrumentation development. [ABSTRACT FROM AUTHOR]

Currently, catalysis research is focusing on nanosized catalysts since they often show an improved activity. It is believed that the improvement is due to their greatly increased surface to volume ratio [1-31, 3]. Evidence is mounting, however, that nanosized catalysts exhibit a good deal of structural diversity and this too may affect their activity substantially [4]. Clearly, future progress in catalysis research depends critically on the ability to obtain precise knowledge about the atomic-scale structure of nanosized catalysts. Here we show how high-energy X-ray diffraction (XRD) can accomplish this task with success. [ABSTRACT FROM AUTHOR]

The literature data on the smallest unit cells as well as on the smallest single crystals studied by X-ray diffraction are reviewed. Different types of phase diagrams “temperature—grain size” are presented and discussed. The literature data on the grain-size driven structural phase transitions occurring in nanocrystals (quantum dots) are presented in the form of a database. It was found that there were no reports on phase transitions occurring for nanocrystalline grains with a linear dimension smaller than 7 unit cells. The grain-size driven phase transitions for some nanocrystalline double tungstates, molybdates and phosphates are also described. [ABSTRACT FROM AUTHOR]

The symmetry of the antiferroelectric phase of PbZrO3 was mainly regarded as C2v8 or D2h9 in the previous literatures. Both of them belong to the orthorhombic system. It is reinvestigated in this paper by symmetry element analysis based on the projective figures given in the related literatures. We find that the symmetry group of this antiferroelectric (AFE) phase is C2h1, and the antiferroelectric crystal PbZrO3 belongs to the monoclinic system. The dielectric tensor measurement was proposed to distinguish the space group C2h1 from C2v8 and D2h9. [ABSTRACT FROM AUTHOR]

The article discusses the highlights of the 2006 United States-China Workshop Series on Neutron Science and Technology. The event took place in Beijing China from Noevmber 12-15, 2006 with moer than 150 participants. This event was sponsored by the National Science Foundation and other concerned organizations. The workshop involved several discussions about the issues and the future of neutron science and technology. It concluded with a panel discussion led by facility leaders covering research and development, neutronics and instrumentation development.

We investigated crystal structure and ferroelectric properties of bismuth layered-structure compounds prepared by alloying Ce substituted Sr1- xCexBi2Ta2O9 (SCBT) with Bi3Si4O12 (BSO) using a solid state reaction method. From the P-E hysteriesis measurement, the SCBT has larger Pr and Ec compared with SBT. Pr increased and Ec decreased by adding BSO to SCBT. The crystal structure was determined by the Rietveld analysis using neutron powder diffraction data. The results of analysis indicated that the SCBT and that added with BSO had a larger spontaneous polarization, and a smaller tilting angle (αa) in comparison with those of SBT. Moreover, the distortion of TaO6 octahedron was changed in the SCBT and that added with BSO. [ABSTRACT FROM AUTHOR]

High-energy synchrotron X-ray measurements (HEXRD) and pair-distribution function (PDF) analysis were carried out to investigate the local structure in ferroelectric Cd 1-x Zn x Te alloy. The Cd 1-x Zn x Te crystallizes in the zinc-blende structure and the PDF analysis revealed that the zinc-blende lattice of the Cd 1-x Zn x Te alloy distorts locally to accommodate the distinct Cd-Te and Zn-Te alloy bond lengths. The local disorder correlate in the <111> direction and it is the origin of macroscopic ferroelectricity in the Cd 1- x Zn x Te alloy. [ABSTRACT FROM AUTHOR]

We use the term “virtual porous carbon” (VPC) to describe computer-based molecular models of nanoporous carbons that go beyond the ubiquitous slit pore model and seek to engage with the geometric, topological and chemical heterogeneity that characterises almost every form of nanoporous carbon. A small number of these models have been developed and used since the early 1990s. These models and their use are reviewed. Included are three more detailed examples of the use of our VPC model. The first is concerned with the study of solid-like adsorbate in nanoporous carbons, the second with the absolute assessment of multi-isotherm based methods for determining the fractal dimension, and the final one is concerned with the fundamental study of diffusion in nanoporous carbons. [ABSTRACT FROM AUTHOR]

Vanadium xerogels intercalated by n -hexadecylamine were prepared in the presence of hexane. The interlayer spacing of the vanadium xerogel was saturated by n -hexadecylamine at a composition of ( n -hexadecylamine) 2.2 V 2 O 5 · 0.6 H 2 O. The space between the n -hexadecylamine molecules in the layer was available for adsorption of dye molecules. Large amounts of rhodamine 6G (2.9 wt%), pyrene (1.8 wt%), and p -terphenyl (3.6 wt%) were monomerically intercalated. The I 1 /I 3 ratios of the emission peak for pyrene in the intercalation compounds were approximately 0.9, suggesting a nonpolar environment of the interlayer space. The N , N -diethlaminoazobenzene molecules in intercalation compounds were highly confined between n -hexadecylamine molecules. [ABSTRACT FROM AUTHOR]

The six-dimensional (6D) low density elimination method (LDEM) has been applied to solve the p-type icosahedral Zn 75 Mg 16 Ho 9 quasicrystal. The reconstructed electron density distribution by the LDEM exhibits three large occupation domains (ODs) centred at (0,?0,?0,?0,?0,?0), (,?,?,?,?,?), and (,?0,?0,?0,?0,?0) in the 6D primitive unit cell, and the OD at (,?,?,?,?,?) contains Ho atoms, which mainly distribute around the threefold directions. A geometrical analysis confirms that a rhombic triacontahedron cluster which includes a Bergman-type cluster is a basic building unit of the structure. [ABSTRACT FROM AUTHOR]

Ceramic solid solutions of PbZr 1- x T x O 3 (PZT) with compositions x ? 0.50 are well-known for their extraordinarily large piezoelectric responses. The latter are highly anisotropic, and it was recently shown that, for the rhombohedral compositions ( x ? 0.5), the piezoelectric coefficients were largest away from the polar direction, contrary to common belief. Shortly afterwards a low-symmetry monoclinic phase was observed by synchrotron X-ray diffraction at around x ?=?0.50. Similar behavior and features are also present in a number of related lead-based strongly-piezoelectric single crystals, such as Pb(Mg 1/3 Nb 2/3 ) 1- x Ti x O 3 , Pb(Zn 1/3 Nb 2/3 ) 1- x Ti x O 3 , and Pb(Sn 1/2 Nb 1/2 ) 1- x Ti x O 3 , with piezoelectric coefficients of about 2500?pm?V -1 , the highest values recorded to date. Recent experimental and theoretical work has greatly improved our understanding of these technologically important systems, but there are still some open questions. In this review, we summarize the most recent progress in the field. [ABSTRACT FROM AUTHOR]