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Mixtures of nonfullerene acceptors (NFAs) are prepared to fine‐tune bulk heterojunction (BHJ) thin‐film morphologies. The acceptor phase resulting from these mixtures has unique physical properties with excellent optoelectronic processes that dictate the output of organic photovoltaic (OPV) devices. Remarkable short‐circuit current densities (JSC) and fill factors (FFs) are achieved due to the formation of better crystalline fibrils that suppress geminate recombination, leading to improved charge transport with enhanced crystallinity and aligned cascading energy levels confirm efficient exciton diffusion and dissociation, yielding more effective exciton recycling. The decreased Urbach energy and suppressed energetic disorder account for the improvement in the open‐circuit voltage (VOC). A maximum power conversion efficiency of 17.86% is obtained, underscoring the importance of using specific material interactions to produce a suitable morphology and manage energy loss, resulting in ideal organic solar cell (OSC) devices. [ABSTRACT FROM AUTHOR]

Heterojunction device performance has strong dependence on its junction interface. ZnO deposition over GaN to achieve a heterojunction is challenging as it usually requires high temperature and vacuum processing. It is even more demanding to achieve a crystalline interface while making ZnO nanorod based heterojunction. Here we report simple solution process for epitaxial growth of ZnO nanorods over GaN. High resolution x-ray diffraction studies revealed highly crystalline c-axis oriented ZnO nanorod growth by a simple hydrothermal process. ZnO/GaN heterojunction device fabricated using hydrothermally synthesized ZnO nanorods showed superior performance compared to polycrystalline sputter deposited ZnO based heterojunction. [ABSTRACT FROM AUTHOR]

Highlights • Linear scans in reciprocal space are examined for coplanar diffraction geometry. • Concept of linear scans is extended to non-coplanar set-up. • Scans and resolution in asymmetric non-coplanar geometry are analyzed and discussed. Abstract High resolution X-ray diffraction is commonly used for the analysis of single crystalline epitaxial layers exhibiting high degree of crystal perfection. The method enables to resolve fine variations of the measured intensities and therefore is very efficient in the investigation of the structural parameters of single or multilayered epitaxial systems. In this article the method combining the standard HR technique with grazing incidence set-up is outlined. It is shown that in non-coplanar geometry the intensity distribution within the section of reciprocal space perpendicular to the sample surface, standardly scanned in coplanar geometry, can be measured at constant angle of incidence α. For asymmetric diffractions that are not accessible in coplanar geometry the value of α can be decreased to extremely low values close to zero making the method depth-sensitive. The effect of non-coplanar geometry on the angular resolution is analyzed and the possible application of φ scans in asymmetric non-coplanar geometry is discussed. The proposed scans are illustrated by measurements on selected GaN based epitaxial layers and they can be applied also to other types of epitaxial systems with medium crystal quality. [ABSTRACT FROM AUTHOR]

Local atomic structure of liquid and amorphous Al 80 − x T x Si 20 (where T = Fe, Co, Ni and x = 10, 15) alloys has been studied by X-ray diffraction (XRD) and molecular dynamics simulations. Chemical short-range order in the liquid and amorphous alloys has been found to be similar to that in the corresponding crystalline counterparts. Formation and evolution of crystalline phases during heat-treatment of the as-quenched ternary alloys up to liquid state were shown using in-situ XRD. Analysis of the morphology of the as-quenched and annealed Al-T-Si ribbons has been performed by transmission electron microscopy. [ABSTRACT FROM AUTHOR]

Two dimensional (2D) materials with layered lattice structure as nanofluid additives are useful to improve the tribological properties of metallic sliding interfaces. To enhance the tribological efficiency, the bulk crystalline hexagonal boron nitride (h-BN) powder sample was mechanically exfoliated by ball milling, and further processed through ultrasonication for de-aggregation. High resolution X-ray diffraction (HR XRD) and high resolution transmission electron microscopy (HR TEM) results clearly indicate the exfoliation of bulk h-BN into thinner two-dimensional (2D) crystalline sheets without creating noticeable structural defects. The topography of exfoliated nanosheets is well confirmed by atomic force microscopy (AFM). Oxygen functionalization into the h-BN nanosheets after the mechanical exfoliation was investigated by X-ray photoelectron spectroscopy (XPS) and Fourier transform infrared spectroscopy (FTIR). Oxygen functionalization of h-BN improved the cohesive compatibility between h-BN and commercial 10W30 lubricant oil for stable dispersion. Friction coefficient and wear of sliding metallic interfaces were reduced significantly in the presence of few layered exfoliated h-BN nanofluid as compared to neat lubricated oil. Micro- XPS and energy-disperse X-ray spectroscopy (EDX) analysis demonstrated the presence of adsorbed h-BN tribofilm in the metallic wear track. Thin 2D sheets of h-BN nanofluid was effective as an additive for low shear resistance under the tribo stressed condition which is the main reason for significant reduction in friction coefficient. Moreover, the enhanced wear resistance of exfoliated h-BN additives was explained by low shear resistance and high compressive/tensile strength of planer sheets which restricted the mechanical damage and protected the metallic interfaces against deformation and wear. [ABSTRACT FROM AUTHOR]

MIL-101(Cr), one of the best investigated and widely used metal–organic frameworks, has been easily synthesized with particle diameters in the range from 387(28) nm to 90(10) nm by using acetic acid as a modulator. The particle size of MIL-101(Cr) decreased with increasing acetic acid concentration. The decrease of size in high concentration of acetic acid may be explained with the efficient suppression of the framework extension. In a selected condition, MIL-101(Cr) possessing an average diameter of about 90 nm can be prepared easily and reproducibly in gram-scale, with high BET-surface areas (3200–3500 m 2 /g) and fairly good yield (60–75%). [ABSTRACT FROM AUTHOR]

In this paper, effect of emulsification processes on the properties of Pickering emulsions stabilized by organomontmorillonites (OMts) was studied. Results of micro-morphology and X-ray diffraction showed that the structure of OMt in emulsion depended on the emulsification processes and had an effect on the stability of emulsion. We propose a schematic diagram to reveal the relationship between emulsification processes-OMt laminates structure-stability of Pickering emulsion. In emulsion prepared by ultrasonic, OMt showed uniform dispersion, loose structure, and irregular crystalline. In emulsion prepared by vortex mixing method, OMt illustrated stacking and coagulation structure. In emulsion prepared by microwave method, OMt showed interacting structure and had a little interaction with oil/water interface, and thus the properties of emulsion prepared by microwave was weakly related to oil/water ratios. Emulsification processes had a profound effect on the structure of OMt and stability of Pickering emulsion, which can be used as a trigger to prepare emulsion for various applications. [ABSTRACT FROM AUTHOR]

A supramolecular complex was constructed by encapsulation of a 3O2 molecule inside an open-cage C60 derivative. Its single-crystal X-ray diffraction analysis revealed the presence of the 3O2 at the center of the fullerene cage. The CV measurements suggested that unprecedented dehydrogenation was promoted by the encapsulated 3O2 after two-electron reduction. The ESR measurements displayed the triplet character as well as the anisotropy of the 3O2. Additionally, the SQUID measurements also demonstrated the paramagnetic behavior above 3 K without an antiferromagnetic transition. Upon photoirradiation with visible light, three phosphorescent bands at the NIR region were observed, arising from the exited 1O2 generated by self-sensitization with the outer cage, whose lifetimes were not affected by the environments. These studies confirmed that the complex is a crystalline triplet system with incompatible 'high spin density' but 'small interspin interaction' properties. [ABSTRACT FROM AUTHOR]

Near-3:2 mullite crystals have been grown successfully with the optical floating zone technique. The growth direction of mullite crystals is along the c axis and growth rate can be reached 10 mm/h. The effect of growth rates on the crystal quality has been studied. The crystalline phase, crystal quality, microstructure, composition distribution of the grown crystals were characterized by powder X-ray diffraction, single crystal X-ray diffraction, scanning electron microscope, electron probe micro-analyzer and Raman spectra, respectively. The grown mullite crystal is formed by peritectic structure with near 3:2 mullite crystal as main face and lamellar or needle-like SiO 2 -rich aluminosilicate as secondary phase that parallel to the crystal growth direction. The measured dielectric properties show large dielectric anisotropy and good temperature stability in near-3:2 mullite crystals. [ABSTRACT FROM AUTHOR]

Time-resolved x-ray diffraction is a very powerful tool for visualizing transient one-dimensional crystalline strains, ranging from crystal growth to shockwave production. In this work, we use picosecond x-ray diffraction to visualize transient strain formation from nanometer-scaled laser-excited gold films into crystalline substrates. We show that there is a direct correspondence between the measured time-resolved x-ray diffraction pattern and the transient acoustic wave, providing a straightforward method to make a reconstruction of the transient strain. In addition, we discuss real-world experimental constraints that place limits on the validity of the reconstructed transient acoustic wave. [ABSTRACT FROM AUTHOR]

The structural properties of nanoscale Ag, La(OH), CuS (covellite), AgS (acanthite), and ZnO hollow spheres, massive Ag nanoparticles and In-Ag core-shell nanoparticles with outer diameters between 200 and 400 Å, were investigated by X-ray diffraction (XRD), high-resolution transmission electron microscopy (HRTEM), scanning transmission electron microscopy (STEM), dynamic light scattering (DLS), and differential sedimentation (DS). Lognormal size distributions of single-crystalline (quasi)spherical nanoparticles are found in our samples by DLS, STEM, DS, and HRTEM. The lattice parameters of the nanomaterials are determined by XRD line-position analysis, while the volume-averaged size and the microstrain are derived by the average-size and strain approximation in the integral breadth method. A new expression is presented in this work to derive the real average outer diameter $$ \bar{D} $$ of hollow spherical particles. The good agreement between $$ \bar{D} $$ and the corresponding diameter determined by DLS in the case of Ag and La(OH) hollow spheres demonstrates the validity of the approach. The same expression is applied to derive the average wall thickness of CuS and AgS hollow spheres as well as for the Ag shell thickness of In-Ag core-shell nanoparticles. [ABSTRACT FROM AUTHOR]

The paper discusses the wear resistance, friction coefficient, and structure of friction surfaces of submicron crystalline Y-TZP-AlO composite rubbed against a steel disk counterface at a pressure of 5 MPa in a range of sliding speeds from 1 to 20 m/sec. It is shown that, starting at 2 m/sec, the friction surface is subdivided by a crack network into separate regions within which local spalling occurs at the maximum wear rate and a sliding speed of 5 m/sec. X-ray diffraction reveals inversion (with respect to the initial state) of the peak intensities of the tetragonal phase with random crystalline grain orientation. The degree of this inversion increases with sliding speed. These results are discussed in terms of the effects exerted by the reorientation of martensite-free deformation twins in the tetragonal phase and the formation of a quasi-liquid film on the wear resistance of Y-TZP-AlO. [ABSTRACT FROM AUTHOR]

By analyzing with X-ray diffraction and FT-IR spectroscopy, the main effective factors among common culture conditions on crystallinity index and I fraction of cellulose produced by Gluconacetobacter xylinus were examined with Plackett-Burman design experiment. Varying pH value in the medium by adjusting the composition of citrate buffer or by adding HCl/NaOH solution indicates it is the content of citrate buffer rather than its function of pH buffering that gives the influence on crystallinity. Further experiment reveals that Na concentration of 0.174 mol/l in medium with citrate buffer added would decrease the crystallinity index significantly. Comparison of carbon sources shows that fructose leads to a higher crystallinity index than glucose, which suggests a relationship between crystallinity and production speed of bacterial cellulose affected by carbon sources. An interesting phenomenon was that a longer period of cultivation would decrease the crystallinity of bacterial cellulose. The reason is assumed to be the dense network of cellulose formed by bacterial cells that restrict the motion of themselves as the incubation period extends. Though the effect of inoculum age is still unclear, the influence on crystallinity of bacterial cellulose caused by variation of some ordinary culture conditions can be drawn out from data of this work. [ABSTRACT FROM AUTHOR]

Abstract: A successful method to epitaxy GaAsBi layer on (001) GaAs substrate is proposed. During growth, alternated trimethyl bismuth (TMBi) flows were used. These TMBi flashes were switched on for a short time. The growth was monitored in situ by laser reflectometry using a 632.8nm beam. The reflectance signal is found to change significantly during both bismuth flashes and GaAs growth stages. High-resolution X-ray diffraction (HRXRD), secondary ion mass spectroscopy (SIMS) and photoreflectance spectroscopy (PR) have been used to characterize the obtained GaAsBi layer. HRXRD curve shows a diffraction peak that can be attributed to a GaAsBi epilayer. SIMS measurements of GaAsBi layer suggest that bismuth diffuses faster near the interface. The PR spectrum indicates the band-to-band transition in GaAsBi layer. The band gap energy was determined by adjusting the PR spectrum with a multilayer model. [Copyright &y& Elsevier]

Abstract: This study investigated the relationship between the hydrolytic stability and the crystalline regions of cured UF resins with different formaldehyde/urea (F/U) mole ratios to better understand the hydrolysis of cured urea–formaldehyde (UF) resin adhesives responsible for its formaldehyde emission in service. As the F/U mole ratio decreased, the hydrolytic stability of cured UF resins improved, but decreased when the particle size of the resin was reduced. To further understand the improved hydrolytic stability of cured UF resin with lower F/U mole ratios, X-ray diffraction (XRD) was extensively used to examine the crystalline part of cured UF resins, depending on F/U mole ratios, cure temperature and time, hardener type and level. Cured UF resins with higher F/U mole ratios (1.6 and 1.4) showed amorphous structure, while those with lower F/U mole ratios (1.2 and 1.0) showed crystalline regions, which could partially explain the improved hydrolytic stability of the cured UF resin. The crystalline part intensity increased as cure temperature, cure time and hardener content increased. But the 2θ angles of these crystalline regions did not change, depending on cure temperature and time, hardener type and level, suggesting that the crystalline regions of the cured UF resin were inherent. This study indicates that the crystalline regions of cured UF resins with lower F/U mole ratio contribute partially to the improved hydrolytic stability of the cured resin. [Copyright &y& Elsevier]

The article presents research which examined the use of high-resolution X-ray diffraction analysis in determining the effect of dopants on the crystalline perfection of ferroelectric glycine phosphite single crystals. The researchers selected dopants in various categories including rare-earth metals, transition metals and amino acids. They also assessed the concentration of dopants based on their crystallization characteristics during the growth process.

A general and facile approach for tailoring the multicolor output and shapes of lanthanide-ion doped fluoride upconversion nanoparticles (UCNPs) within a given composition is presented. By adjusting the temperature and time in the thermolysis procedure, the color output and shapes of NaYF4:20%Yb, 2%Er UCNPs can be readily manipulated. The nanoparticles were characterized through the use of transmission electron microscopy (TEM), powder X-ray diffraction (XRD) and upconversion luminescence spectroscopy. It is shown that the relative intensities of green emissions gradually increased with the rise of temperature and prolongation of growth time under excitation of 980 nm, which resulted in multicolor output of NaYF4:20%Yb, 2%Er UCNPs. Simultaneously, the shapes for UCNPs can also be controlled. TEM images, estimated micro-stress by Williamson–Hall methodology and a series of control experiments and analyses reveal that crystallinity is mainly responsible for the multicolor output of UCNPs. Based on the above method, the tailoring of color output is also successfully realized in Ho3+and Tm3+ions. It is expected that this method may be used to tune the physical properties of other nanoparticles, and these multicolored UCNPs are promising for applications in multiplexed bioimaging, biodetection, display, other optical technologies, etc. [ABSTRACT FROM AUTHOR]

Abstract: A new photocatalyst, namely single-crystalline Bi5O7NO3 nanofibers, was prepared by a facile hydrothermal method in the presence of Triton X-100 and ammonia. Bi5O7NO3 possessing a crystalline sheet morphology could be dissolved and transformed into nanofibers by controlling the reaction time. Samples were characterized by X-ray diffraction, UV–vis diffuse reflectance spectroscopy, X-ray photoelectron spectroscopy, scanning electron microscopy, transmission electron microscopy and high resolution transmission electron microscopy. The Bi5O7NO3 nanofiber growth mechanism is discussed in detail. The band gap energy of the as-prepared Bi5O7NO3 photocatalyst was about 2.70–2.90eV. Results of first-principle density functional theory calculations confirmed that Bi5O7NO3 had a narrow band gap. They revealed that the conduction band bottom was predominantly composed of Bi 6s, Bi 6p, N 2p and O 2p orbitals, while the valence band (VB) top primarily consisted of Bi 6p, Bi 6s and O 2p orbitals. The as-obtained Bi5O7NO3 nanofibers showed good photocatalytic activity and stability for the degradation of Rhodamine B (RhB) under visible light irradiation, which may be ascribed to the highly mobile conduction band (CB) and VB charge carriers. [ABSTRACT FROM AUTHOR]

Abstract: Eu(BO2)3 nanowires with diameters of 10–20nm were fabricated through direct sintering Eu(NO3)3·6H2O and H3BO3 with Ag as catalyst. The result of X-ray diffraction (XRD) indicated that the nanowire was single-crystalline with body-centered monoclinic structure. Based on the fact that Ag nanoparticles attached to the tips and middles of nanowires, a vapor–liquid–solid (VLS) growth mechanism of the Eu(BO2)3 nanowires is proposed. Three well-defined stages have been clearly identified during the process: Ag–Eu–B–O cluster process, crystal nucleation, and axial growth. The photoluminescence characteristics under UV excitation were investigated. The dominated Eu3+ orange–red emission corresponding to the magnetic dipole transition 5D0 → 7F1 is centered at 591nm, indicating that Eu3+ is located at high symmetry crystal field with inversion center. [ABSTRACT FROM AUTHOR]

The article presents a study on the crystal structure of M2As2O7 diarsenates, a transition metal which is considered as a variant of thortveitite structure. The study used differential scanning calorimetry (DSC), single-crystal X-ray diffraction, and X-ray powder diffraction to analyze its structure. It concludes that the incommensurability of ∝2-Cr2P2O7 and ∝-Zn2As2O7 structures is due to the interplay between metal oxide sequences in diarsenates atoms and X2O7 structure.

The article presents a study which investigates the structure of N-(5-ethyl-[1,3,4]-thiadiazole-2-yl)-toluenesulfonamide compound. The study used X-ray powder diffraction (XRPD) data analysis, direct-space methods, and Carbon (C) cross-polarization magic angle-spinning (CP/MAS) spectrum analysis to determine the structure of the compound. Results showed that C atoms in the compound contains only one molecule in its asymmetric unit and is not a mixture of different form of crystalline elements.

Removal of arsenate (As(V)) from aqueous solution using both nanocrystalline and coprecipitated Mg/Al layered double hydroxides (LDHs) was examined under different sorption/desorption conditions. The surface area, pore volume, and pore size of the nanocrystalline LDH were significantly higher than those of the coprecipitated LDH, thus resulting in a higher As(V) sorption maximum than the coprecipitated LDH. The calculated activation energy (Ea) value was 24.7 kJ/mol, suggesting the occurrence of anion exchange process for As(V) removal by the nanocrystalline LDH. The predominance of anion exchange process was further supported by the investigation of ionic strength effect, and XRD and FTIR analyses. The effect of aqueous matrix on As(V) sorption by the nanocrystalline LDH was found to increase in the order of nitrate < silica < sulfate < carbonate < phosphate. Regeneration study showed that a secondary sorption mechanism might occur concurrently for the As(V) sorption by nanocrystalline LDH besides the predominant anion exchange process. Prospects and challenges for practical application of the nanocrystalline LDH were also discussed in the latter part of this study. [ABSTRACT FROM AUTHOR]

1,3,5,7-Telramethyl-1 ,3,5,7-tetrahydroxycycloletrasiloxane has been synthesized in good yield from tetrapotassium tetramethytcyclotetrasiloxanolate. Methods for isolation of all-cis-somer I and cis-trans-cis-isomer II as Ihe only crystalline product have been developed. Both isomers have been characterized by single-crystal X-ray diffraction analysis (XRD), elemental analysis, NMR (1H, 13C, 13Si), and IR. The stability of these compounds in solutions and the solid state has been investigated. [ABSTRACT FROM AUTHOR]

Nowadays, hard coatings based on transition metal nitrides are extensively used for materials protection and particularly to improve the lifetime and performance of various cutting and forming tools. Practically, hard coatings need to be deposited on different kinds of substrate materials in different application areas. The physical properties, such as hardness, of the substrate may have evident influence on the properties and performance of the hard coatings. In this work, different kinds of hard coatings, including TiN, CrN, TiAlN, and CrAlN, were deposited by a lateral rotating cathode arc technique on two kinds of steel substrates with different hardness. The composition, crystalline structure, mechanical and tribological properties of the as-deposited hard coatings were systematically analyzed by energy dispersive analysis of X-rays, X-ray diffraction, nanoindentation, pin-on-disc tribometer, Rockwell indentation, and scratch test, respectively. The influence of substrate hardness on the properties of the hard coatings was investigated. It was found that the substrate hardness has little influence on the crystalline structure, nano-hardness, and tribological properties (friction coefficient and wear rate). However, it showed a significant effect of the toughness and adhesion of the hard coatings. It can be concluded that hard coatings need to be supported by hard substrates. [ABSTRACT FROM AUTHOR]

Novel bulk glassy samples of the pseudoternary chalcohalide Ge–S–AgI system have been prepared. Glasses have been obtained by monotemperature synthesis in evacuated ampoules and standard melt-quenching technique. The glass-forming region in the system determined by X-ray diffraction is situated in the S-rich region on the Ge–S side (S/Ge = 1.2, 1.5, 2 and 3) with AgI content up to 20 mol.%. Some physicochemical properties of the amorphous materials and their compositional dependence have been investigated. In addition, the theoretical average coordination number (Z), the total constraints per atom (Nco), the radial (Na) and axial (Nb) strength of the bonds have been calculated and related to the experimental results. [ABSTRACT FROM AUTHOR]

'In situ' wide angle (WAXS) and small angle X-ray scattering (SAXS) studies were carried out to characterize the structural changes occurring during the conversion of a polyamic acid into the polyimide in the presence of fullerene, C60. The variations in crystallinity, long period, and the SAXS invariant of the samples are discussed in the light of the various temperature ranges studied. The conversion of the polyamic acid into the polyimide is analyzed according to the different structural steps. Results reveal that C60 affects the degree of order of the composite in the molecular direction, giving rise to slightly smaller crystals than those found in pure polyamic acid. The difference in the SAXS data between the pure PAA and the composite are discussed through the interaction of C60 molecules with the polyamic acid, which seems to hinder the imidization reaction up to 185°C. [ABSTRACT FROM AUTHOR]

Abstract: The crystal structure of the new ternary compound TmCu4−x Sb2 (x =1.065) was determined by direct methods from X-ray powder data (diffractometer DRON-3M, Cu Kα-radiation). It crystallizes with the orthorhombic structure type ErFe4Ge2 (low-temperature modification) and is the first representative of this structure type among known antimonides: space group Pnnm, Pearson code oP14-2.13, a =7.00565(6)Å, b =7.83582(6)Å, c =4.25051(3)Å, Z =2. Investigated structure is an orthorhombically deformed derivative of the ZrFe4Si2 structure type. [Copyright &y& Elsevier]

The effect of heat treatment on the structure, hardness, and electrical resistivity of the crystalline Sn 100- x In x ( x ?=?10?wt.%) solder alloy is studied. The structures of as-casted and heat-treated alloys have been investigated by means of a X-ray diffraction technique. Using X-ray analysis a crystalline ß-Sn and an In phase are detected. The amount of the crystalline phases increases upon increasing the annealing temperature. It is found that the fracture is delayed from 8.6?kg/mm 2 at 50?s and 100?g at room temperature to 4?kg/mm 2 at 90?s and 100?g at 423?K. Differential thermal analysis was used to investigate the melting characteristics of the alloy (m.p. ~214 ° C). The resistivity is also determined for samples thermally and non-thermally treated. [ABSTRACT FROM AUTHOR]

Understanding the effect of overlaps on microstructure and performance of laser treated surface layer is of fundamental importance for the development and application of laser surface treatment of engineering materials. In the present work, laser surface melting of 321 austenitic stainless steel with overlaps and single laser track was carried out using a 2 kW CO2 laser and a 3 kW CW Nd:YAG laser respectively. The crystallization of the melted surface layers and their preferred orientation were characterized by X-ray diffraction. It was found that the heat treatment effect at overlap regions caused not only the transformation of some δ-ferrite formed in previous laser tracks reversed into γ-austenite, but also the increase in the extent of the preferred orientation of γ-austenite along [200] direction. Relationships between phase composition and laser process parameters such as laser power lever, beam size, scanning velocity and overlap ratio have been also studied. [Copyright &y& Elsevier]

The purpose of this study was to determine quantitatively the crystallinity in crystalline/amorphous powder mixtures of lactose, to asses the capability of Near Infrared Spectroscopy (NIRS) for quantitative determination of crystallinity and to compare the accuracy of the NIRS method with that of conventional X-ray powder diffraction (XRPD). Amorphous lactose was prepared by spray drying. Samples with different crystallinity were prepared by physical mixing of 100% amorphous and 100% crystalline materials. The samples were characterized by XRPD and NIRS. Analysis was performed on the data sets by multiple linear regression (MLR). There is a close correlation between the predicted and the actual crystallinity of physical mixtures of crystalline and amorphous lactose, determined by NIRS (R2=0.9994). NIRS results were compared to the XRPD using the same sample sets. The correlation coefficients was 0.9981. The results showed that NIRS is an useful method for accurately determining low quantities of the crystalline lactose in a physical mixture. Therefore, NIRS can be used for the quantitative determination of crystallinity of materials during pharmaceutical procedures. [Copyright &y& Elsevier]

Cubic boron nitride (c-BN) nanocrystals have been synthesized by pulsed laser induced liquid–solid interfacial reaction. It is shown that the diameters of the prepared quasi-spherical c-BN nanocrystals vary from 30 to 80 nm via transmission electron microscopy (TEM). The 2θ values of the X-ray diffraction (XRD) peaks of the resultant c-BN nanocrystals are 43.16°, 74.16°, 90.08° and 136.1°, respectively, corresponding to the (1 1 1), (2 2 0), (3 1 1) and (3 3 1) crystalline planes of a c-BN phase. Fourier transform infrared (FTIR) spectroscopy has also been used to characterize the structure of boron nitride. The formation of c-BN nanocrystals upon pulsed laser ablation at the liquid–solid interface is discussed in detail. [Copyright &y& Elsevier]

Crystalline complex of 1-piperidineacetic acid with perchloric acid, PAAH·ClO4, has been prepared and characterised by X-ray diffraction method at 100 K and refined to the R=0.022 (I>2σ(I)). The crystals are orthorhombic, space group P212121, with a=6.607(1), b=8.171(2), c=18.651(4) A˚, Z=4, V=1006.9(4) A˚3. The N–H proton is in an axial position and the CH2COOH substituent in an equatorial one. The COOH group is involved in two hydrogen bonds; one with the ClO4− anion, O(2)–H(2)⋯O(1′)=2.664(1) A˚, and the second with the N+–H proton of a neighbouring molecule, related by the twofold screw axis parallel to x; O(1)⋯H(11)–N(1)=2.957(1) A˚. The N+–H proton forms a trifurcated (four-centre) hydrogen bond. The two contacts of the N+–H hydrogen atom, an intermolecular with the ClO4− anion and an intramolecular with the O&z.dbnd6;C group are formed. Each ClO4− anion is surrounded by five 1-piperidiniumacetic acid molecules and each oxygen atom interacts electrostatically with three positively charged nitrogen atoms. Powdered spectra of PAAH·ClO4 and its deuterated analogue were measured and assignment of the observed bands to vibrations of the hydrogen bonds and internal vibrations are proposed. The NH⋯O and OH⋯O hydrogen bonds are manifested by superimposition of a broad and smooth absorption in the 3300–2800 cm−1 region with a maximum at 3120 cm−1. [Copyright &y& Elsevier]

The correlation between the vicinal properties of SrTiO[sub 3] (001) substrates and the twinning in YBa[sub 2]Cu[sub 3]O[sub 7-x] thin films grown by pulsed-laser deposition is studied using x-ray diffraction with reciprocal space mapping. The vicinal properties, i.e., angle and in-plane orientation, play a significant role in the anisotropic strain starting at the interface between substrate surface and film, and affect the twin behavior of YBa[sub 2]Cu[sub 3]O[sub 7-x]. On substrates having an [110] in-plane orientation of the step edges, a completely preferred twin pair is observed if the vicinal angle is increased to 0.60°. Whereas on substrates having their step edges oriented along one of the crystallographic axis, the films exhibit a detwinning as the vicinal angle increases. For α=1.10° a maximum detwinned, i.e., monocrystalline film is obtained. At this angle, the diffusion length of YBa[sub 2]Cu[sub 3]O[sub 7-x] during the growth matches the terrace length of SrTiO[sub 3]. Up to this specific angle, the films are grown perpendicular to the optical instead of the crystallographic surface. © 2003 American Institute of Physics. [ABSTRACT FROM AUTHOR]

4H-polytype AlN has been grown on a 4H-SiC substrate with the (1120) face via plasma-assisted molecular-beam epitaxy. The microscopic structure of the AlN/4H-SiC interface was examined using high-resolution transmission electron microscopy, and the polytype replication of the 4H structure from the 4H-SiC(1120) substrate was evidently confirmed. The x-ray rocking curve of (1120) diffraction for the single crystalline 4H-AlN epilayer exhibited a very small linewidth of 90 arc sec, suggesting noticeably small tilting around the [1120] direction. The excellent crystalline quality is probably owing to the polytype matching between the 4H-AlN epilayer and the 4H-SiC substrate, which resulted in remarkable reduction of defects at the interface. © 2003 American Institute of Physics. [ABSTRACT FROM AUTHOR]