pi Ace of Swords Reversed: Symbolism and Spiritual Implications By entertainment.howstuffworks.com Published On :: Tue, 12 Nov 2024 05:00:03 -0500 Discover the meaning of the Ace of Swords reversed in tarot. Explore its insights on clarity, communication, and inner conflicts in love, career, and personal growth. Full Article
pi What Reversed Compatibility Reveals About Pisces and Cancer Pairing By entertainment.howstuffworks.com Published On :: Tue, 12 Nov 2024 05:30:03 -0500 Explore reversed Pisces and Cancer compatibility! Learn how these water signs bond emotionally, support each other deeply, and thrive together in relationships. Full Article
pi KOSPI Up 0.04% on Thursday By world.kbs.co.kr Published On :: Thu, 07 Nov 2024 15:42:26 +0900 [Economy] : The benchmark Korea Composite Stock Price Index rose one-point-12 points, or zero-point-04 percent, on Thursday to close at two-thousand-564-point-63. The tech-heavy KOSDAQ slid nine-point-79 points, or one-point-32 percent, to close at 733-point-52.[more...] Full Article Economy
pi KOSPI Slips 0.14% on Friday By world.kbs.co.kr Published On :: Fri, 08 Nov 2024 15:52:04 +0900 [Economy] : The benchmark Korea Composite Stock Price Index shed three-point-48 points, or zero-point-14 percent, on Friday to close at two-thousand-561-point-15. The tech-heavy KOSDAQ gained nine-point-86 points, or one-point-34 percent, to close at 743-point-38.[more...] Full Article Economy
pi KOSPI Down 1.15% on Monday By world.kbs.co.kr Published On :: Mon, 11 Nov 2024 15:47:09 +0900 [Economy] : The benchmark Korea Composite Stock Price Index dipped 29-point-49 points, or one-point-15 percent, on Monday to close at two-thousand-531-point-66. The tech-heavy KOSDAQ slid 14-point-54 points, or one-point-96 percent, to close at 728-point-84.[more...] Full Article Economy
pi KOSPI Down 1.94% on Tuesday By world.kbs.co.kr Published On :: Tue, 12 Nov 2024 15:39:55 +0900 [Economy] : The benchmark Korea Composite Stock Price Index dipped 49-point-09 points, or one-point-94 percent, on Tuesday to close at two-thousand-482-point-57. The tech-heavy KOSDAQ slid 18-point-32 points, or two-point-51 percent, to close at 710-point-52.[more...] Full Article Economy
pi KOSPI Slips below 2,500 Threshold for First Time since Black Monday in August By world.kbs.co.kr Published On :: Tue, 12 Nov 2024 17:55:50 +0900 [Economy] : South Korea’s benchmark Korea Composite Stock Price Index(KOSPI) slipped below the two-thousand-500 threshold on Tuesday for the first time since August’s “Black Monday.” The KOSPI dipped 49-point-09 points, or one-point-94 percent, on Tuesday to close at two-thousand-482-point-57. In the ...[more...] Full Article Economy
pi KOSPI Plunges 2.64% on Wednesday By world.kbs.co.kr Published On :: Wed, 13 Nov 2024 15:45:45 +0900 [Economy] : The benchmark Korea Composite Stock Price Index tumbled 65-point-49 points, or two-point-64 percent, on Wednesday to close at two-thousand-417-point-08. The tech-heavy KOSDAQ sank 20-point-87 points, or two-point-94 percent, to close at 689-point-65.[more...] Full Article Economy
pi BGS completes first mapping expedition to Ascension Island - British Geological Survey By news.google.com Published On :: Mon, 11 Dec 2023 08:00:00 GMT BGS completes first mapping expedition to Ascension Island British Geological Survey Full Article
pi The Geography Olympiad: Bandung, Indonesia - British Geological Survey By news.google.com Published On :: Fri, 22 Dec 2023 08:00:00 GMT The Geography Olympiad: Bandung, Indonesia British Geological Survey Full Article
pi Structural insights into 1,4-bis(neopentyloxy)pillar[5]arene and the pyridine host–guest system By journals.iucr.org Published On :: The crystal structure of a neopentyloxypillar[5]arene with two pyridine molecules encapsulated in the macrocyclic cavity is reported. Full Article text
pi A contribution to the crystal chemistry and topology of organic thiosulfates: bis(1-methylpiperazinium)·S2O3·H2O versus 1-methylpiperazinediium·S2O3·3H2O By journals.iucr.org Published On :: Crystal structure and topology of two new thiosulfates formed with mono- and diprotonated species of 1-methylpiperazine is reported. Full Article text
pi From `crystallographic accuracy' to `thermodynamic accuracy': a redetermination of the crystal structure of calcium atorvastatin trihydrate (Lipitor®) By journals.iucr.org Published On :: The crystal structure of calcium atorvastatin trihydrate was redetermined from previously published synchrotron powder diffraction data to give a much-improved agreement with two independent density-functional theory calculations. Full Article text
pi Spin reorientation and the interplay of magnetic sublattices in Er2CuMnMn4O12 By journals.iucr.org Published On :: We show that the interplay of multiple magnetic sublattices in Er2CuMnMn4O12 leads to four magnetic phase transitions characterized by the onset of ferrimagnetic order, spin-reorientation, spin canting, and the polarization of Er ions. While we elucidate numerous features of this complex magnetic system, the exact nature of the low-temperature coupling between erbium and manganese, and the origin of a k = (0, 0, ½) modulation, remain intriguing topics for future studies. Full Article text
pi Atypical phase transition, twinning and ferroelastic domain structure in bis(ethylenediammonium) tetrabromozincate(II) bromide, [NH3(CH2)2NH3]2[ZnBr4]Br2 By journals.iucr.org Published On :: A unique phase transition, twinning and ferroelastic domain structure in [NH3(CH2)2NH3]2[ZnBr4]Br2 is found. The new additional domain structure is observed at the phase transition on heating, which is preserved after cooling to room temperature. Full Article text
pi Coordination geometry flexibility driving supramolecular isomerism of Cu/Mo pillared-layer hybrid networks By journals.iucr.org Published On :: The hydrothermal synthesis and structural characterization of four novel 3D pillared-layer metal–organic frameworks are studied, revealing how the malleability of copper coordination geometries drives diverse supramolecular isomerism. The findings provide new insights into designing advanced hybrid materials with tailored properties, emphasizing the significant role of reaction conditions and metal ion flexibility in determining network topologies. Full Article text
pi Seed layer formation by deposition of micro-crystallites on a revolving substrate: modeling of the effective linear elastic, piezoelectric, and dielectric coefficients By journals.iucr.org Published On :: The rotating substrate method of crystallite deposition is modeled, allowing computation of effective material coefficients of the layers resulting from the averaging. A worked numerical example particularized to 6mm ZnO is provided. Full Article text
pi Selective Acceleration and Inhibition of Crystal Growth of Glass Carbamazepine by Low-Concentration Poly(ethylene oxide):Effects of Drug Polymorph By journals.iucr.org Published On :: Low-concentration poly(ethylene oxide) exhibit the polymorph-dependent effects on both the surface and bulk crystal growth of carbamazepine polymorphs. These polymorph-dependent effects of PEO were mainly attributed to the polymer enrichment at the interface and different crystal surface-polymer interactions. Full Article text
pi Atypical phase transition, twinning and ferroelastic domain structure in bis(ethylenediammonium) tetrabromozincate(II) bromide, [NH3(CH2)2NH3]2[ZnBr4]Br2 By journals.iucr.org Published On :: 2024-11-04 Single-crystal growth, differential thermal analysis (DTA), derivative thermogravimetry (DTG), differential scanning calorimetry (DSC), X-ray structural studies and polarized microscopy observations of bis(ethylenediammonium) tetrabromozincate(II) bromide [NH3(CH2)2NH3]2[ZnBr4]Br2 are presented. A reversible phase transition is described. At room temperature, the complex crystallizes in the monoclinic system. In some cases, the single crystals are twinned into two or more large domains of ferroelastic type with domain walls in the (100) crystallographic plane. DTA and DTG measurements show chemical stability of the crystal up to ∼538 K. In the DSC studies, a reversible isostructural phase transition was revealed at ∼526/522 K on heating/cooling run, respectively. Optical observation on the heating run reveals that at the phase transition the plane of twinning (domain wall) does not disappear and additionally the appearance of a new domain structure of ferroelastic type with domain walls in the planes (101), (101), (100) and (001) is observed. The domain structure pattern is preserved after cooling to the room-temperature phase and the symmetry of this phase is unchanged. Full Article text
pi From `crystallographic accuracy' to `thermodynamic accuracy': a redetermination of the crystal structure of calcium atorvastatin trihydrate (Lipitor®) By journals.iucr.org Published On :: 2024-10-08 With ever-improving quantum-mechanical computational methods, the accuracy requirements for experimental crystal structures increase. The crystal structure of calcium atorvastatin trihydrate, which has 56 degrees of freedom when determined with a real-space algorithm, was determined from powder diffraction data by Hodge et al. [Powder Diffr. (2020), 35, 136–143]. The crystal structure was a good fit to the experimental data, indicating that the electron density had been captured essentially correctly, but two independent quantum-mechanical calculations disagreed with the experimental structure and with each other. Using the same experimental data, the crystal structure was redetermined from scratch and it was shown that it can be reproduced within a root-mean-square Cartesian displacement of 0.1 Å by two independent quantum-mechanical calculations. The consequences for the calculated energies and solubilities are described. Full Article text
pi Spin reorientation and the interplay of magnetic sublattices in Er2CuMnMn4O12 By journals.iucr.org Published On :: 2024-10-21 Through a combination of magnetic susceptibility, specific heat, and neutron powder diffraction measurements we have revealed a sequence of four magnetic phase transitions in the columnar quadruple perovskite Er2CuMnMn4O12. A key feature of the quadruple perovskite structural framework is the complex interplay of multiple magnetic sublattices via frustrated exchange topologies and competing magnetic anisotropies. It is shown that in Er2CuMnMn4O12, this phenomenology gives rise to multiple spin-reorientation transitions driven by the competition of easy-axis single ion anisotropy and the Dzyaloshinskii–Moriya interaction; both within the manganese B-site sublattice. At low temperature, one Er sublattice orders due to a finite f-d exchange field aligned parallel to its Ising axis, while the other Er sublattice remains non-magnetic until a final, symmetry-breaking phase transition into the ground state. This non-trivial low-temperature interplay of transition metal and rare-earth sublattices, as well as an observed k = (0, 0, ½) periodicity in both manganese spin canting and Er ordering, raises future challenges to develop a complete understanding of the R2CuMnMn4O12 family. Full Article text
pi Room-temperature serial synchrotron crystallography structure of Spinacia oleracea RuBisCO By journals.iucr.org Published On :: 2024-05-29 Ribulose-1,5-bisphosphate carboxylase/oxygenase (RuBisCO) is the enzyme responsible for the first step of carbon dioxide (CO2) fixation in plants, which proceeds via the carboxylation of ribulose 1,5-biphosphate. Because of the enormous importance of this reaction in agriculture and the environment, there is considerable interest in the mechanism of fixation of CO2 by RuBisCO. Here, a serial synchrotron crystallography structure of spinach RuBisCO is reported at 2.3 Å resolution. This structure is consistent with earlier single-crystal X-ray structures of this enzyme and the results are a good starting point for a further push towards time-resolved serial synchrotron crystallography in order to better understand the mechanism of the reaction. Full Article text
pi Mapping domain structures near a grain boundary in a lead zirconate titanate ferroelectric film using X-ray nanodiffraction By journals.iucr.org Published On :: Direct measurements have been taken of nanoscale domain structure in ferroelectric lead zirconate titanate around a grain boundary. Characterizing the evolution of this structure under an electric field is critical for predicting dielectric and piezoelectric response. Full Article text
pi Improving the reliability of small- and wide-angle X-ray scattering measurements of anisotropic precipitates in metallic alloys using sample rotation By journals.iucr.org Published On :: Rotations of small- and wide-angle X-ray scattering samples during acquisition are shown to give a drastic improvement in the reliability of the characterization of anisotropic precipitates in metallic alloys. Full Article text
pi The effects of low boron incorporation on the structural and optical properties of BxGa1−xN/SiC epitaxial layers By journals.iucr.org Published On :: The effect of boron in BxGa1−xN/SiC heteroepitaxy was established by X-ray diffraction reciprocal-space maps on symmetric 0002 and asymmetric 11 {overline 2} 4 reflections. The density of screw and edge threading dislocations was quantified in the framework of the mosaic model. Full Article text
pi Characterization and calibration of DECTRIS PILATUS3 X CdTe 2M high-Z hybrid pixel detector for high-precision powder diffraction measurements By journals.iucr.org Published On :: The performance of a high-Z photon-counting detector for powder diffraction measurements at high (>50 keV) energies is characterized, and the appropriate corrections are described in order to obtain data of higher quality than have previously been obtained from 2D detectors in these energy ranges. Full Article text
pi Modulating phase segregation during spin-casting of fullerene-based polymer solar-cell thin films upon minor addition of a high-boiling co-solvent By journals.iucr.org Published On :: Combined 100 ms resolved grazing-incidence small/wide-angle X-ray scattering and optical interferometry reveal that the additive diiodooctane can significantly double the solvent evaporation rate, thereby effectively suppressing the rapid spinodal decomposition process in the early stage of spin-coasting, favouring slow phase segregation kinetics with nucleation and growth. Full Article text
pi RAPID, an ImageJ macro for indexing electron diffraction zone axis spot patterns of cubic materials By journals.iucr.org Published On :: RAPID (RAtio method Pattern InDexing) is an ImageJ macro script developed for the quick determination of sample orientation and indexing of calibrated and uncalibrated zone axis aligned electron diffraction patterns from materials with a cubic crystal structure. In addition to SAED and NBED patterns, the program is also capable of handling zone axis TEM Kikuchi patterns and FFTs derived from HR(S)TEM images. The software enables users to rapidly determine whether materials are cubic, pseudo-cubic, or non-cubic, and to distinguish between P, I, and F Bravais lattices. It can also provide lattice parameters for material verification and aid in determining the camera constant of the instrument, thus making the program a convenient tool for on-site crystallographic analysis in the TEM laboratory. Full Article text
pi Synthesis, crystal structure and Hirshfeld surface analysis of N-(4-methoxyphenyl)picolinamide By journals.iucr.org Published On :: The molecular and crystal structure of N-(4-methoxyphenyl)picolinamide were studied and Hirshfeld surfaces and fingerprint plots were generated to investigate various intermolecular interactions. Full Article text
pi The effects of low boron incorporation on the structural and optical properties of BxGa1−xN/SiC epitaxial layers By journals.iucr.org Published On :: 2024-11-04 BGaN epilayers with boron contents up to 5.6% were grown on SiC substrates by metal–organic chemical vapor deposition. The effects of boron incorporation on the structural and optical properties were studied by high-resolution X-ray diffraction (XRD), atomic force microscopy (AFM), Raman spectroscopy and photoluminescence (PL) spectroscopy. XRD reciprocal-space maps around the symmetric 0002 and asymmetric 11 {overline 2} 4 reflections allowed evaluation of the lattice constants and lattice mismatch with respect to the underlying substrate. XRD rocking curves and AFM measurements indicated the mosaic microstructure of the epilayer. The impact of boron content on crystallite size, tilt and twist is evaluated and the correlation with threading dislocation density is discussed. The deterioration of optical properties with increasing boron content was assessed by Raman and PL spectroscopy. Full Article text
pi Improving the reliability of small- and wide-angle X-ray scattering measurements of anisotropic precipitates in metallic alloys using sample rotation By journals.iucr.org Published On :: 2024-11-04 Nanometric precipitates in metallic alloys often have highly anisotropic shapes. Given the large grain size and non-random texture typical of these alloys, performing small- and wide-angle X-ray scattering (SAXS/WAXS) measurements on such samples for determining their characteristics (typically size and volume fraction) results in highly anisotropic and irreproducible data. Rotations of flat samples during SAXS/WAXS acquisitions are presented here as a solution to these anisotropy issues. Two aluminium alloys containing anisotropic precipitates are used as examples to validate the approach with a −45°/45° angular range. Clear improvements can be seen on the SAXS I(q) fitting and the consistency between the different SAXS/WAXS measurements. This methodology results in more reliable measurements of the precipitate's characteristics, and thus allows for time- and space-resolved measurements with higher accuracy. Full Article text
pi Mapping domain structures near a grain boundary in a lead zirconate titanate ferroelectric film using X-ray nanodiffraction By journals.iucr.org Published On :: 2024-10-29 The effect of an electric field on local domain structure near a 24° tilt grain boundary in a 200 nm-thick Pb(Zr0.2Ti0.8)O3 bi-crystal ferroelectric film was probed using synchrotron nanodiffraction. The bi-crystal film was grown epitaxially on SrRuO3-coated (001) SrTiO3 24° tilt bi-crystal substrates. From the nanodiffraction data, real-space maps of the ferroelectric domain structure around the grain boundary prior to and during application of a 200 kV cm−1 electric field were reconstructed. In the vicinity of the tilt grain boundary, the distributions of densities of c-type tetragonal domains with the c axis aligned with the film normal were calculated on the basis of diffracted intensity ratios of c- and a-type domains and reference powder diffraction data. Diffracted intensity was averaged along the grain boundary, and it was shown that the density of c-type tetragonal domains dropped to ∼50% of that of the bulk of the film over a range ±150 nm from the grain boundary. This work complements previous results acquired by band excitation piezoresponse force microscopy, suggesting that reduced nonlinear piezoelectric response around grain boundaries may be related to the change in domain structure, as well as to the possibility of increased pinning of domain wall motion. The implications of the results and analysis in terms of understanding the role of grain boundaries in affecting the nonlinear piezoelectric and dielectric responses of ferroelectric materials are discussed. Full Article text
pi Lattice symmetry relaxation as a cause for anisotropic line broadening and peak shift in powder diffraction By journals.iucr.org Published On :: 2024-10-03 In powder diffraction, lattice symmetry relaxation causes a peak to split into several components which are not resolved if the degree of desymmetrization is small (pseudosymmetry). Here the equations which rule peak splitting are elaborated for the six minimal symmetry transitions, showing that the resulting split peaks are generally broader and asymmetric, and suffer an hkl-dependent displacement with respect to the high-symmetry parent peak. These results will be of help in Rietveld refinement of pseudosymmetric structures where an exact interpretation of peak deformation is required. Full Article text
pi An alternative method to the Takagi–Taupin equations for studying dark-field X-ray microscopy of deformed crystals By journals.iucr.org Published On :: 2024-09-26 This study introduces an alternative method to the Takagi–Taupin equations for investigating the dark-field X-ray microscopy (DFXM) of deformed crystals. In scenarios where dynamical diffraction cannot be disregarded, it is essential to assess the potential inaccuracies of data interpretation based on the kinematic diffraction theory. Unlike the Takagi–Taupin equations, this new method utilizes an exact dispersion relation, and a previously developed finite difference scheme with minor modifications is used for the numerical implementation. The numerical implementation has been validated by calculating the diffraction of a diamond crystal with three components, wherein dynamical diffraction is applicable to the first component and kinematic diffraction pertains to the remaining two. The numerical convergence is tested using diffraction intensities. In addition, the DFXM image of a diamond crystal containing a stacking fault is calculated using the new method and compared with the experimental result. The new method is also applied to calculate the DFXM image of a twisted diamond crystal, which clearly shows a result different from those obtained using the Takagi–Taupin equations. Full Article text
pi An active piezoelectric plane X-ray focusing mirror with a linearly changing thickness By journals.iucr.org Published On :: 2024-01-01 X-ray mirrors for synchrotron radiation are often bent into a curved figure and work under grazing-incidence conditions due to the strong penetrating nature of X-rays to most materials. Mirrors of different cross sections have been recommended to reduce the mirror's slope inaccuracy and clamping difficulty in order to overcome mechanical tolerances. With the development of hard X-ray focusing, it is difficult to meet the needs of focusing mirrors with small slope error with the existing mirror processing technology. Deformable mirrors are adaptive optics that can produce a flexible surface figure. A method of using a deformable mirror as a phase compensator is described to enhance the focusing performance of an X-ray mirror. This paper presents an active piezoelectric plane X-ray focusing mirror with a linearly changing thickness that has the ability of phase compensation while focusing X-rays. Benefiting from its special structural design, the mirror can realize flexible focusing at different focusing geometries using a single input driving voltage. A prototype was used to measure its performance under one-dimension and two-dimension conditions. The results prove that, even at a bending magnet beamline, the mirror can easily achieve a single-micrometre focusing without a complicated bending mechanism or high-precision surface processing. It is hoped that this kind of deformable mirror will have a wide and flexible application in the synchrotron radiation field. Full Article text
pi PINK: a tender X-ray beamline for X-ray emission spectroscopy By journals.iucr.org Published On :: 2024-04-25 A high-flux beamline optimized for non-resonant X-ray emission spectroscopy (XES) in the tender X-ray energy range has been constructed at the BESSY II synchrotron source. The beamline utilizes a cryogenically cooled undulator that provides X-rays over the energy range 2.1 keV to 9.5 keV. This energy range provides access to XES [and in the future X-ray absorption spectroscopy (XAS)] studies of transition metals ranging from Ti to Cu (Kα, Kβ lines) and Zr to Ag (Lα, Lβ), as well as light elements including P, S, Cl, K and Ca (Kα, Kβ). The beamline can be operated in two modes. In PINK mode, a multilayer monochromator (E/ΔE ≃ 30–80) provides a high photon flux (1014 photons s−1 at 6 keV and 300 mA ring current), allowing non-resonant XES measurements of dilute substances. This mode is currently available for general user operation. X-ray absorption near-edge structure and resonant XAS techniques will be available after the second stage of the PINK commissioning, when a high monochromatic mode (E/ΔE ≃ 10000–40000) will be facilitated by a double-crystal monochromator. At present, the beamline incorporates two von Hamos spectrometers, enabling time-resolved XES experiments with time scales down to 0.1 s and the possibility of two-color XES experiments. This paper describes the optical scheme of the PINK beamline and the endstation. The design of the two von Hamos dispersive spectrometers and sample environment are discussed here in detail. To illustrate, XES spectra of phosphorus complexes, KCl, TiO2 and Co3O4 measured using the PINK setup are presented. Full Article text
pi Developing an in situ LED irradiation system for small-angle X-ray scattering at B21, Diamond Light Source By journals.iucr.org Published On :: 2024-05-31 Beamline B21 at the Diamond Light Source synchrotron in the UK is a small-angle X-ray scattering (SAXS) beamline that specializes in high-throughput measurements via automated sample delivery systems. A system has been developed whereby a sample can be illuminated by a focused beam of light coincident with the X-ray beam. The system is compatible with the highly automated sample delivery system at the beamline and allows a beamline user to select a light source from a broad range of wavelengths across the UV and visible spectrum and to control the timing and duration of the light pulse with respect to the X-ray exposure of the SAXS measurement. The intensity of the light source has been characterized across the wavelength range enabling experiments where a quantitative measure of dose is important. Finally, the utility of the system is demonstrated via measurement of several light-responsive samples. Full Article text
pi Mapping of lithium ion concentrations in 3D structures through development of in situ correlative imaging of X-ray Compton scattering-computed tomography By journals.iucr.org Published On :: 2024-06-05 Understanding the correlation between chemical and microstructural properties is critical for unraveling the fundamental relationship between materials chemistry and physical structures that can benefit materials science and engineering. Here, we demonstrate novel in situ correlative imaging of the X-ray Compton scattering computed tomography (XCS-CT) technique for studying this fundamental relationship. XCS-CT can image light elements that do not usually exhibit strong signals using other X-ray characterization techniques. This paper describes the XCS-CT setup and data analysis method for calculating the valence electron momentum density and lithium-ion concentration, and provides two examples of spatially and temporally resolved chemical properties inside batteries in 3D. XCS-CT was applied to study two types of rechargeable lithium batteries in standard coin cell casings: (1) a lithium-ion battery containing a cathode of bespoke microstructure and liquid electrolyte, and (2) a solid-state battery containing a solid-polymer electrolyte. The XCS-CT technique is beneficial to a wide variety of materials and systems to map chemical composition changes in 3D structures. Full Article text
pi TomoPyUI: a user-friendly tool for rapid tomography alignment and reconstruction By journals.iucr.org Published On :: 2024-06-26 The management and processing of synchrotron and neutron computed tomography data can be a complex, labor-intensive and unstructured process. Users devote substantial time to both manually processing their data (i.e. organizing data/metadata, applying image filters etc.) and waiting for the computation of iterative alignment and reconstruction algorithms to finish. In this work, we present a solution to these problems: TomoPyUI, a user interface for the well known tomography data processing package TomoPy. This highly visual Python software package guides the user through the tomography processing pipeline from data import, preprocessing, alignment and finally to 3D volume reconstruction. The TomoPyUI systematic intermediate data and metadata storage system improves organization, and the inspection and manipulation tools (built within the application) help to avoid interrupted workflows. Notably, TomoPyUI operates entirely within a Jupyter environment. Herein, we provide a summary of these key features of TomoPyUI, along with an overview of the tomography processing pipeline, a discussion of the landscape of existing tomography processing software and the purpose of TomoPyUI, and a demonstration of its capabilities for real tomography data collected at SSRL beamline 6-2c. Full Article text
pi PEPICO analysis of catalytic reactor effluents towards quantitative isomer discrimination: DME conversion over a ZSM-5 zeolite By journals.iucr.org Published On :: 2024-06-25 The methanol-to-hydrocarbons (MTH) process involves the conversion of methanol, a C1 feedstock that can be produced from green sources, into hydrocarbons using shape-selective microporous acidic catalysts – zeolite and zeotypes. This reaction yields a complex mixture of species, some of which are highly reactive and/or present in several isomeric forms, posing significant challenges for effluent analysis. Conventional gas-phase chromatography (GC) is typically employed for the analysis of reaction products in laboratory flow reactors. However, GC is not suitable for the detection of highly reactive intermediates such as ketene or formaldehyde and is not suitable for kinetic studies under well defined low pressure conditions. Photoelectron–photoion coincidence (PEPICO) spectroscopy has emerged as a powerful analytical tool for unraveling complex compositions of catalytic effluents, but its availability is limited to a handful of facilities worldwide. Herein, PEPICO analysis of catalytic reactor effluents has been implemented at the FinEstBeAMS beamline of MAX IV Laboratory. The conversion of dimethyl ether (DME) on a zeolite catalyst (ZSM-5-MFI27) is used as a prototypical model reaction producing a wide distribution of hydrocarbon products. Since in zeolites methanol is quickly equilibrated with DME, this reaction can be used to probe vast sub-networks of the full MTH process, while eliminating or at least slowing down methanol-induced secondary reactions and catalyst deactivation. Quantitative discrimination of xylene isomers in the effluent stream is achieved by deconvoluting the coincidence photoelectron spectra. Full Article text
pi TEMPUS, a Timepix4-based system for the event-based detection of X-rays By journals.iucr.org Published On :: 2024-07-23 TEMPUS is a new detector system being developed for photon science. It is based on the Timepix4 chip and, thus, it can be operated in two distinct modes: a photon-counting mode, which allows for conventional full-frame readout at rates up to 40 kfps; and an event-driven time-stamping mode, which allows excellent time resolution in the nanosecond regime in measurements with moderate X-ray flux. In this paper, the initial prototype, a single-chip device, is introduced, and the readout system described. Moreover, and in order to evaluate its capabilities, some tests were performed at PETRA III and ESRF for which results are also presented. Full Article text
pi Vibrational stability improvement of a mirror system using active mass damping By journals.iucr.org Published On :: 2024-08-08 Addressing the demand for high stability of beamline instruments at the SHINE facility, a high stability mirror regulating mechanism has been developed for mirror adjustments. Active mass damping was adopted to attenuate pitch angle vibrations of mirrors caused by structural vibrations. An internal absolute velocity feedback was used to reduce the negative impact of spillover effects and to improve performance. The experiment was conducted on a prototype structure of a mirror regulating mechanism, and results showed that the vibration RMS of the pitch angle was effectively attenuated from 47 nrad to 27 nrad above 1 Hz. Full Article text
pi 1-Ethyl-3,3-dimethylspiro[indoline-2,8'-phenaleno[1,9-fg]chromene] By journals.iucr.org Published On :: 2024-02-13 The title pyrene-fused spiropyran derivative, C30H25NO, crystallizes with two molecules in the asymmetric unit with dihedral angles between their fused-ring sub units of 76.20 (8) and 89.38 (9)°. In the crystal, weak C—H⋯π interactions link the molecules into a three-dimensional network. Full Article text
pi 6-[4-(tert-Butyldimethylsilyloxy)phenyl]-1-oxaspiro[2.5]heptane By journals.iucr.org Published On :: 2024-06-21 The title compound, C19H30O2Si, has triclinic (Poverline{1}) symmetry at 100 K. The O atom of the epoxide group has a pseudoaxial orientation and the dihedral angle between the cyclohexyl and benzene rings is 85.80 (8)°. The C—O—Si—Ct (t = tert-butyl) torsion angle is −177.40 (14)°. In the crystal, pairwise C—H⋯O links connect the molecules into inversion dimers featuring R22(8) loops. Full Article text
pi Pinaverium bromide By journals.iucr.org Published On :: 2024-08-06 The structure of pinaverium bromide (systematic name: 4-[(2-bromo-4,5-dimethoxyphenyl)methyl]-4-{2-[2-(6,6-dimethyl-2-bicyclo[3.1.1]heptanyl)ethoxy]ethyl}morpholin-4-ium bromide; C26H41Br2NO4), was determined at 110 K. It has monoclinic (P21) symmetry. It is of interest with respect to its anti-inflammatory properties. The asymmetric unit contains two independent molecules, one of which exhibits disorder of the bicyclo terminal group (occupancy factors: 0.78 and 0.22). Full Article text
pi Redetermined structure of methyl 3-{4,4-difluoro-2-[2-(methoxycarbonyl)ethyl]-1,3,5,7-tetramethyl-4-bora-3a,4a-diaza-s-indacen-6-yl}propionate By journals.iucr.org Published On :: 2024-09-17 In the title compound, C21H27BF2N2O4, a highly fluorescent boron–dipyrromethene dye, the methylpropionate moieties have different conformations. In the crystal, weak C—H⋯F and C—H⋯O interactions link the molecules. Some optical properties are presented. Full Article text
pi 1,4-Dimethylpiperazine-2,3-dione By journals.iucr.org Published On :: 2024-10-04 In the title compound, C6H10N2O2, the piperazine-2,3-dione ring adopts a half-chair conformation. In the crystal, the molecules are linked by weak C—H⋯O hydrogen bonds, forming (010) sheets. Full Article text
pi Structural insights into 1,4-bis(neopentyloxy)pillar[5]arene and the pyridine host–guest system By journals.iucr.org Published On :: 2024-11-08 The crystal structure of 1,4-bis(neopentyloxy)pillar[5]arene, C95H140N2O10 (TbuP), featuring two encapsulated pyridine molecules, reveals significant host–guest interactions. Interestingly, the pyridine guests are positioned near the neopentyloxy substituents instead of the electron-rich aromatic core of the pillar[5]arene. This spatial arrangement suggests a preference for the pyridine molecules to engage with the aliphatic regions of the host. Detailed analysis of the structural characteristics of this host–guest system (TbuP·2Py), as well as its packing pattern within the crystal network, is presented and discussed. Full Article text
pi Borotropic shifting of the hydrotris[3-(2-furyl)pyrazol-1-yl]borate ligand in high-coordinate lanthanide complexes By journals.iucr.org Published On :: 2024-04-16 The coordination of hydrotris[3-(2-furyl)pyrazol-1-yl]borate (Tp2-Fu, C21H16BN6O3) to lanthanide(III) ions is achieved for the first time with the complex [Ln(Tp2-Fu)2](BPh4)·xCH2Cl2 (1-Ln has Ln = Ce and x = 2; 1-Dy has Ln = Dy and x = 1). This was accomplished via both hydrous (Ln = Ce) and anhydrous methods (Ln = Dy). When isolating the dysprosium analogue, the filtrate produced a second crop of crystals which were revealed to be the 1,2-borotropic-shifted product [Dy(κ4-Tp2-Fu)(κ5-Tp2-Fu*)](BPh4) (2) {Tp2-Fu* = hydrobis[3-(2-furyl)pyrazol-1-yl][5-(2-furyl)pyrazol-1-yl]borate}. We conclude that the presence of a strong Lewis acid and a sterically crowded coordination environment are contributing factors for the 1,2-borotropic shifting of scorpionate ligands in conjunction with the size of the conical angle with the scorpionate ligand. Full Article text
pi Crystal structures, electron spin resonance, and thermogravimetric analysis of three mixed-valence copper cyanide polymers By journals.iucr.org Published On :: 2024-05-01 The crystal structures of three mixed-valence copper cyanide alkanolamine polymers are presented, together with thermogravimetric analysis (TGA) and electron spin resonance (ESR) data. In all three structures, a CuII moiety on a crystallographic center of symmetry is coordinated by two alkanolamines and links two CuICN chains via cyanide bridging groups to form diperiodic sheets. The sheets are linked together by cuprophilic CuI–CuI interactions to form a three-dimensional network. In poly[bis(μ-3-aminopropanolato)tetra-μ-cyanido-dicopper(I)dicopper(II)], [Cu4(CN)4(C3H8NO)2]n, 1, propanolamine bases have lost their hydroxyl H atoms and coordinate as chelates to two CuII atoms to form a dimeric CuII moiety bridged by the O atoms of the bases with CuII atoms in square-planar coordination. The ESR spectrum is very broad, indicating exchange between the two CuII centers. In poly[bis(2-aminopropanol)tetra-μ-cyanido-dicopper(I)copper(II)], [Cu3(CN)4(C3H9NO)2]n, 2, and poly[bis(2-aminoethanol)tetra-μ-cyanido-dicopper(I)copper(II)], [Cu3(CN)4(CH7NO)2]n, 3, a single CuII atom links the CuICN chains together via CN bridges. The chelating alkanolamines are not ionized, and the OH groups form rather long bonds in the axial positions of the octahedrally coordinated CuII atoms. The coordination geometries of CuII in 2 and 3 are almost identical, except that the Cu—O distances are longer in 2 than in 3, which may explain their somewhat different ESR spectra. Thermal decomposition in 2 and 3, but not in 1, begins with the loss of HCN(g), and this can be correlated with the presence of OH protons on the ligands in 2 and 3, which are not present in 1. Full Article text