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The Advanced X-ray Imaging Satellite (AXIS) promises revolutionary science in the X-ray and multi-messenger time domain. AXIS will leverage excellent spatial resolution (<1.5 arcsec), sensitivity ( 80 × that of Swift), and a large collecting area (5–10× that of Chandra) across a 24-arcmin diameter field of view at soft X-ray energies (0.3–10.0 keV) to discover and characterize a wide range of X-ray transients from supernova-shock breakouts to tidal disruption events to highly variable supermassive black holes. The observatory's ability to localize and monitor faint X-ray sources opens up new opportunities to hunt for counterparts to distant binary neutron star mergers, fast radio bursts, and exotic phenomena like fast X-ray transients. AXIS will offer a response time of <2 h to community alerts, enabling studies of gravitational wave sources, high-energy neutrino emitters, X-ray binaries, magnetars, and other targets of opportunity. This white paper highlights some of the discovery science that will be driven by AXIS in this burgeoning field of time domain and multi-messenger astrophysics. This White Paper is part of a series commissioned for the AXIS Probe Concept Mission; additional AXIS White Papers can be found at the AXIS website. [ABSTRACT FROM AUTHOR]

The paper presents the results of experimental studies of the operation of hybrid X-pinches on a modified high-current KING generator. The KING generator is a portable pulse current generator based on four low-inductive pulse capacitors. The output assembly of the generator was modified for greater diagnostic access to the load, which led to an increase in the inductance of the entire circuit and an increase in the duration of the current rise. A series of experiments with hybrid X-pinches with Al, Cu, and Mo wires with a diameter of 25 μm was carried out on the modified KING generator (200–260 kA, 220–280 ns, 45 kV). In experiments, it was shown that such a modification of the generator led to the stable formation of bright soft x-ray sources in X-pinches, suitable for use in point-projection radiography with a spatial resolution of about 10–15 μm. [ABSTRACT FROM AUTHOR]

A plane-symmetric optical system with a two-dimensional field light source, such as a soft X-ray and vacuum ultraviolet optical system, is widely used for synchrotron radiation source devices, microscopes and so on. Therefore, this paper studied third-order intrinsic aberration modification with second-order accuracy transfer of pupil coordinates and extrinsic aberration of these kinds of optical systems. First, we discuss the extrinsic aberration calculation method and derive the corresponding aberration expressions; in addition, we apply optical geometric relations and the polynomial fitting method to obtain a second-order accuracy transfer relationship expression of the pupil coordinates between adjacent optical surfaces and derived the modification calculation expressions of the intrinsic aberration caused by the above factor. Finally, the third-order intrinsic aberration modification with second-order accuracy transfer of pupil coordinates and extrinsic aberration expressions derived in this paper are applied to calculate ray spot diagrams of two soft X-ray and vacuum ultraviolet optical systems with meridional and sagittal field angle light sources, and these results are compared with those obtained from the ray-tracing software Shadow; this showed that the calculation accuracy of the aberration expressions is sufficient. [ABSTRACT FROM AUTHOR]

This paper proposes an array structure with multidirectional remanent magnetization based on hard-magnetic soft materials, which can be used as a soft switch array on planar and curved surfaces. We firstly investigate the displacement response of a hard-magnetic soft switch which is excited by a magnetic field, and related to the magnitude and direction of the magnetic field. When the remanent magnetization direction of the soft switch is opposite to the horizontal component of the magnetic field, the displacement response is greater than that of the driving magnetic field in other directions. The maximum displacement of the soft switch can reach 4.5 mm under a 6 V driving voltage applied to the Helmholtz coil. We further design 2 × 2 and 3 × 3 switch arrays and the circuit structures of the switch arrays. The switch arrays are fabricated, and the displacement responses of the switch arrays under different driving magnetic fields on planar and curved surfaces are finally demonstrated. When the Z-axis displacement of the device reaches more than 3 mm, the LED light can be switched on. The hard-magnetic soft switch array structure designed in this paper can enable the application of soft switches in curved environments, verifying the feasibility of the application of hardmagnetic soft switch arrays. It is expected to provide a guidance for the design and manufacturing of multi-functional hard-magnetic soft switches in the future and the application of hard-magnetic soft switch arrays in planar and curved environments. [ABSTRACT FROM AUTHOR]

Large-bandwidth pulses produced by cutting-edge X-ray free-electron lasers (FELs) are of great importance in research fields like material science and biology. In this paper, a new method to generate high-power ultrashort FEL pulses with tunable spectral bandwidth with spectral coherence using a dielectric-lined waveguide without interfering operation of linacs is proposed. By exploiting the passive and dephasingless wakefield at terahertz frequency excited by the beam, stable energy modulation can be achieved in the electron beam and large-bandwidth high-intensity soft X-ray radiation can be generated. Three-dimensional start-to-end simulations have been carried out and the results show that coherent radiation pulses with duration of a few femtoseconds and bandwidths ranging from 1.01% to 2.16% can be achieved by changing the undulator taper profile. [ABSTRACT FROM AUTHOR]

In this paper, we report on a systematic study of a soft X-ray Gas Electron Multiplier (GEM) detector built with aluminium-clad kapton GEM foils. The primary objective of this research is to comprehend the performance of this type of detector when irradiated with soft energy photons. The results are analysed and discussed with a particular focus on the long-term detector stability, as well as its gas gain and energy resolution uniformity across the detector area. Presented results lead us to the conclusion that the aluminium based GEM detector is a promising device to suppress the X-ray Fluorescence (XRF) background, simultaneously providing very good stability during long-term measurement campaigns. [ABSTRACT FROM AUTHOR]

In the present paper, we apply a blind fitting algorithm to model two-dimensional energy-incidence angle maps of soft x-ray resonant reflectivity measured in nanoscale epitaxial multilayers of multiferroic ε-Fe2O3 grown by pulsed laser deposition. The possibility of fitting the spectral shape of the complex refraction index across the Fe L3 absorption edge without having an initial guess about the optical constants has been demonstrated. The spectral shape fitting of the real (f1) and imaginary (f2) parts of the atomic scattering factor has been carried out by using a specially designed software utilizing OpenCL fast calculations on graphical processing units. The Kramers-Kronig relations between f1 and f2 are automatically taken into account by the fitting algorithm. A reasonable agreement between blindly generated and reference scattering factor spectra derived independently from an x-ray absorption spectroscopy experiment has been demonstrated. The blind fitting has been compared with the alternative refinement routines, in which small free variations of the reference spectral shapes (or no variations at all) have been allowed. The presented approach to the resonant x-ray reflectometry modeling makes it unnecessary to acquire the optical constant spectral shapes in advance and, thus, is especially helpful when such spectra cannot be physically measured, e.g., for a buried layer of a multilayer system. [ABSTRACT FROM AUTHOR]

Since the discovery of the cosmic X-ray background (CXB), astronomers have strived to understand the accreting supermassive black holes (SMBHs) contributing to its peak in the 10-40 keV band. Existing soft X-ray telescopes could study this population up to only 10 keV, and, while NuSTAR (focusing on 3-24 keV) made great progress, it also left significant uncertainties in characterizing the hard X-ray population, crucial for calibrating current population synthesis models. This paper presents an in-depth analysis of simulations of two extragalactic surveys (deep and wide) with the High-Energy X-ray Probe (HEX-P), each observed for 2 Ms. Applying established source detection techniques, we show that HEX-P surveys will reach a flux of ~10-15 erg s-1 cm-2 in the 10-40 keV band, an order of magnitude fainter than current NuSTAR surveys. With the large sample of new hard X-ray detected sources (~2000), we showcase HEX-Ps ability to resolve more than 80% of the CXB up to 40 keV into individual sources. The expected precision of HEX-Ps resolved background measurement will allow us to distinguish between population synthesis models of SMBH growth. HEX-P will leverage accurate broadband (0.5-40 keV) spectral analysis and the combination of soft and hard X-ray colors to provide obscuration constraints even for the fainter sources, with the overall objective of measuring the Compton-thick fraction. With unprecedented sensitivity in the 10-40 keV band, HEX-P will explore the hard X-ray emission from AGN to flux limits never reached before, thus expanding the parameter space for serendipitous discoveries. Consequently, it is plausible that new models will be needed to capture the population HEX-P will unveil. [ABSTRACT FROM AUTHOR]

When first introduced, single-photon counting detectors reshaped crystallography at synchrotrons. Their fast readout speed enabled, for example, shutter-less data collection and fine slicing of the rotation angle and boosted the development of new experimental techniques like ptychography. Under optimal conditions, single-photon counting detectors provide an unlimited dynamic range with image noise only limited by the Poisson statistics of the incoming photons. Counting the pulses from individual photons, essentially what made the detectors so successful, also causes the main drawback, which is the loss of efficiency at high photon fluxes due to pulse pileup in the analog front end. To fully take advantage of diffraction-limited light sources, the next-generation single-photon counters need to improve their count rate capabilities in the same order of magnitude as the increased flux. Moreover, fast frame rates (a few kHz) are required to cope with the shorter dwell time achievable, thanks to the higher flux. Detector architecture with multiple comparators and counters can open new possibilities for energy-resolved imaging, while interpixel communication can overcome the issues arising from charge sharing and reduce the loss of efficiency at the pixel corners. Coupling single-photon counting detectors to high-Z sensors for hard X-ray detection (> 20 keV) and to low-gain avalanche diodes (LGADs) for soft X-rays is also necessary to make use of the increased coherence of the new light sources over the full radiation spectrum. In this paper, we present possible strategies to improve the performance of single-photon counting detectors at the fourth-generation synchrotron sources and compare them to charge integrating detectors. [ABSTRACT FROM AUTHOR]

Multimodal imaging and spectroscopy like concurrent scanning transmission X-ray microscopy (STXM) and X-ray fluorescence (XRF) are highly desirable as they allow retrieving complementary information. This paper reports on the design, development, integration and field testing of a novel in situ atomic force microscopy (AFM) instrument for operation under high vacuum in a synchrotron soft X-ray microscopy STXM–XRF end-station. A combination of μXRF and AFM is demonstrated for the first time in the soft X-ray regime, with an outlook for the full XRF–STXM–AFM combination. [ABSTRACT FROM AUTHOR]

The launch of the IXPE telescope in late 2021 finally made polarization measurements in the 2– 8 keV band a reality, more than 40 years after the pioneering observations of the OSO-8 satellite. In the first two years of operations, IXPE targeted more than 60 sources, including four magnetars, neutron stars with magnetic fields in the petaGauss range. In this paper we summarize the IXPE main findings and discuss their implications for the physics of ultra-magnetized neutron stars. Polarimetric observations confirmed theoretical predictions, according to which X-ray radiation from magnetar sources is highly polarized, up to ≈ 80 % , the highest value detected so far. This provides an independent confirmation that magnetars are indeed endowed with a super-strong magnetic field and that the twisted magnetosphere scenario is the most likely explanation for their soft X-ray emission. Polarization measurements allowed us to probe the physical conditions of the star's outermost layers, showing that the cooler surface regions are in a condensed state, with no atmosphere on top. Although no smoking-gun of vacuum QED effects was found, the phase-dependent behavior of the polarization angle strongly hints that vacuum birefringence is indeed at work in magnetar magnetospheres. [ABSTRACT FROM AUTHOR]

Hybrid pixel detectors have become indispensable at synchrotron and X-ray free-electron laser facilities thanks to their large dynamic range, high frame rate, low noise, and large area. However, at energies below 3 keV, the detector performance is often limited because of the poor quantum efficiency of the sensor and the difficulty in achieving single-photon resolution due to the low signal-to-noise ratio. In this paper, we address the quantum efficiency of silicon sensors by refining the design of the entrance window, mainly by passivating the silicon surface and optimizing the dopant profile of the n+ region. We present the measurement of the quantum efficiency in the soft X-ray energy range for silicon sensors with several process variations in the fabrication of planar sensors with thin entrance windows. The quantum efficiency for 250 eV photons is increased from almost 0.5% for a standard sensor to up to 62% as a consequence of these developments, comparable to the quantum efficiency of backside-illuminated scientific CMOS sensors. Finally, we discuss the influence of the various process parameters on quantum efficiency and present a strategy for further improvement. [ABSTRACT FROM AUTHOR]

The Pohang-Accelerator-Laboratory X-ray free-electron laser (PAL-XFEL) emits intense, ultra-short X-ray pulses, enabling studies on ultra-small and -fast dynamics in various fields. We designed and fabricated silicon p-intrinsic-n photo-diodes (PDs) to detect strong X-ray pulses. Four types of PDs were fabricated with different metal shapes on the P- and N-sides. The fabrication process was split into two parts, based on the thickness of the Al metal and anti- reflective coating (ARC) layers, to evaluate the fabrication process feasibility and the detection performance. A beam test was performed with X-ray pulses at the soft X-ray beamline of the PAL-XFEL using the proposed PDs and a commercial PD. The test was designed to evaluate the effects of the metal and ARC layers and compare the detection efficiency depending on the X-ray entrance side and signal readout side. The waveforms were saved during the test and integrated to obtain the charges. Thereafter, they were analyzed and normalized, and compared. This paper presents the preparation, setup, and procedure of the beam test, and the test results are described. [ABSTRACT FROM AUTHOR]

The Shanghai Soft X-ray Free-Electron Laser (SXFEL) is the first X-ray freeelectron laser facility in China. The SASE beamline, which consists of a pinkbeam branch and a mono-beam branch, is one of the two beamlines in the Phase-I construction. The pink-beam branch opened for users in 2023 after successful first-round beamline commissioning. In this paper, the design of the beamline is presented and the performance of the pink-beam branch is reported. The measured energy-resolving power of the online spectrometer is over 6000 @ 400 eV. The focusing spot size of the pink beam is less than 3 μm in both the horizontal and vertical at the endstation. [ABSTRACT FROM AUTHOR]

In order to understand the nature of super-Eddington accretion we must explore both the emission emerging directly from the inflow and its impact on the surroundings. In this paper, we test whether we can use the optical line emission of spatially resolved, ionized nebulae around ultraluminous X-ray sources (ULXs) as a proxy for their X-ray luminosity. We choose the ULX NGC 6946 X-1 and its nebula, MF16, as a test case. By studying how the nebular optical line emission responds to assumed irradiation, we can infer the degree to which we require the UV or X-ray emission from the inflow to be collimated by optically thick winds seemingly ubiquitously associated with ULXs. We find that the nebula is highly sensitive to compact UV emission but mostly insensitive to hard X-rays. Our attempts to quantify the beaming of the soft and hard X-rays therefore strongly depends on the UV luminosity of the ULX in the centre of the nebula. We find that it is not possible to conclude a lack of geometrical beaming of hard X-rays from such sources via nebula feedback. [ABSTRACT FROM AUTHOR]

A systematic comparison of the models of the circumgalactic medium (CGM) and their observables is crucial to understanding the predictive power of the models and constraining physical processes that affect the thermodynamics of CGM. This paper compares four analytic CGM models: precipitation, isentropic, cooling flow, and baryon pasting models for the hot, volume-filling CGM phase, all assuming hydrostatic or quasi-hydrostatic equilibrium. We show that for fiducial parameters of the CGM of a Milky Way (MW)-like galaxy (⁠|$M_{\rm vir} \sim 10^{12}~{\rm M}_{\odot }$| at |$z\sim 0$|⁠), the thermodynamic profiles – entropy, density, temperature, and pressure – show most significant differences between different models at small (⁠|$r\lesssim 30$|  kpc) and large scales (⁠|$r\gtrsim 100$|  kpc) while converging at intermediate scales. The slope of the entropy profile, which is one of the most important differentiators between models, is |$\approx 0.8$| for the precipitation and cooling flow models, while it is |$\approx 0.6$| and 0 for the baryon pasting and isentropic models, respectively. We make predictions for various observational quantities for an MW mass halo for the different models, including the projected Sunyaev–Zeldovich effect, soft X-ray emission (0.5–2 keV), dispersion measure, and column densities of oxygen ions (O  vi , O  vii , and O  viii) observable in absorption. We provide Python packages to compute the thermodynamic and observable quantities for the different CGM models. [ABSTRACT FROM AUTHOR]

A series of nine new soft salts based on two platinum(II) complexes, namely ([Pt(C^N)(CN)2]−[Pt(C^N)(en)]+) (en = ethane-1,2-diamine), has been developed and synthesized. Their photophysical properties in both solution and the solid state were described. All soft salt complexes exhibit phosphorescence emission with PLQY in the solid state up to 0.36. Most of these materials displayed aggregation-induced emission (AIE) or aggregation-induced emission enhancement (AIEE) in water/DMSO solutions as the water ratio increased. Structure–property relationships were analyzed in relation to emission properties. The presence of the free nitrogen atoms in soft salt complexes with a C^N pyrimidine-based ligand allowed for reversible sensitivity to acidic vapors, resulting in the quenching of phosphorescence emission. Additionally, for selected soft salts, we described reversible vapochromism behaviour, making these new materials interesting for multi-detection purposes in anti-counterfeiting applications. [ABSTRACT FROM AUTHOR]

High quantum efficiency (QE) X-ray absorbers are needed for future X-ray astrophysics telescopes. The Advanced Telescope for High ENergy Astrophysics (ATHENA) mission requirements for the X-ray Integral Field Unit (X-IFU) instrument dictate, at their most stringent, that the absorber achieve vertical QE > 90.6% at 7 keV and low total heat capacity, 0.731 pJ/K. The absorber we have designed is 313 µm square composed of 1.05 μm Au and 5.51 μm electroplated Bi films (Barret et al. in Exp Astron 55:373–426, 2023). Overhanging the TES, the absorber is mechanically supported by 6 small legs whose 5 μm diameter is tuned to the target thermal conductance for the device. Further requirements for the absorber for X-IFU include a > 40% reflectance at wavelengths from 1 to 20 μm to reduce shot noise from infrared radiation from higher temperature stages in the cryostat. We meet this requirement by capping our absorbers with an evaporated Ti/Au thin film. Additionally, narrow gaps between absorbers are required for high fill fraction, as well as low levels of fine particulate remaining on the substrate and zero shorts between absorbers that may cause thermal crosstalk. The Light Element Mapper (LEM) is an X-ray probe concept optimized to explore the soft X-ray emission from 0.2 to 2.0 keV. These pixels for LEM require high residual resistance ratio (RRR) thin 0.5 µm Au absorbers to thermalize uniformly and narrow < 2 μm gaps between pixels for high areal fill fraction. This paper reports upon technology developments required to successfully yield arrays of pixels for both mission concepts and presents first testing results of devices with these new absorber recipes. [ABSTRACT FROM AUTHOR]

This article presents a demonstration of the improved performance of an X‐ray free‐electron laser (FEL) using the optical klystron mechanism and helical undulator configuration, in comparison with the common planar undulator configuration without optical klystron. The demonstration was carried out at Athos, the soft X‐ray beamline of SwissFEL. Athos has variable‐polarization undulators, and small magnetic chicanes placed between every two undulators to fully exploit the optical klystron. It was found that, for wavelengths of 1.24 nm and 3.10 nm, the required length to achieve FEL saturation is reduced by about 35% when using both the optical klystron and helical undulators, with each effect accounting for about half of the improvement. Moreover, it is shown that a helical undulator configuration provides a 20% to 50% higher pulse energy than planar undulators. This work represents an important step towards more compact and high‐power FELs, rendering this key technology more efficient, affordable and accessible to the scientific community. [ABSTRACT FROM AUTHOR]

The origins of quasi-periodic eruptions (QPEs) are poorly understood, although most theoretical explanations invoke an accretion disc around a supermassive black hole. The gas and stellar environments in the galactic nuclei of these sources are also poorly constrained. In this paper, we present an analysis of archival Hubble Space Telescope (HST) images to study the narrow-line [O  iii ] emission in the QPE source GSN 069. We find strong evidence for a compact nuclear [O  iii ] emission region of size ≲ 35 pc, overlaid on top of extended [O  iii ] emission up to 1 kpc away from the nucleus. The age of the accretion system is estimated to be between 10 and 100 yr. The [O  iii ] luminosity of the compact region was measured to be |$(2.1 \pm 0.3) \times 10^{40}\, \rm erg\, s^{-1}$|⁠. Based on cloudy simulations, we constrain that the [O  iii ] emitting gas has a hydrogen number density in the range |$2 \times 10^{3} \lt n_{\rm H} \lesssim 10^{8}\, \rm cm^{-3}$| and volume filling factor f V < 4 × 10−3. We suggest that the dense gas in the nuclear region of GSN 069 originates from molecular clouds (with total mass |$\gtrsim 3 \times 10^{3}\, {\rm M}_{\odot }$|⁠), which are freshly ionized by the soft X-ray photons from the accretion disc. We predict possible evolution of the compact narrow-line region on emission-line diagnostic diagrams, and hence future HST or integral-field unit observations can be used to further pin down the age of this puzzling system. [ABSTRACT FROM AUTHOR]

This paper presents a correlation between time evolution of ions and electrons with soft and hard x-rays emitted from argon plasma. The plasma setup comprises of two copper electrodes connected with a dc power supply. Faraday cups were used to monitor time evolution of ions, to extract their energy, temperature, and flux. Double Langmuir probe was employed to determine electron temperature, energy, and density. To explore time-resolved emission of soft x-rays, PIN photodiodes filtered with 24 μm aluminum, 90 μm Mylar, 80 μm copper, and 10 μm silver have been used. To evaluate temporal evolution of hard x-rays, a scintillator–photomultiplier system was utilized. The plasma was generated using argon gas at atmospheric pressure 760 Torr and constant flow rate 5 L/min at 7, 9, and 11 kV. The flux, energy, and temperature of Ar ions increase with the increase in the operating potential. Soft x-ray signals last much longer (3000 ns) than those of electrons' and ions' signals (300 ns). The plasma operated at 11 kV permits highest emission of ions, electrons, and x-rays. The ions, electrons, and hard and soft x-ray irradiation on silicon wafer exhibited the presence of damaged trails. Ion irradiation showed the presence of latent damaged trails. Electron irradiation caused more damage to the Si surface compared to ion irradiation due to higher flux and density. Soft x-rays had a lesser effect as compared to Si exposed to hard x-rays due to higher energy of the hard x-rays. In the case of hard x-rays irradiated Si, erupted volcano-like structure is formed. [ABSTRACT FROM AUTHOR]

Calculations and measurements of polarization-dependent soft X-ray scattering intensity are presented during a magnetic hysteresis cycle. It is confirmed that the dependence of the intensity on the magnetic moment can be linear, quadratic or a combination of both, depending on the polarization of the incident X-ray beam and the direction of the magnetic moment. With a linearly polarized beam, the scattered intensity will have a purely quadratic dependence on the magnetic moment when the magnetic moment is parallel to the scattering plane. However, with the magnetic moment perpendicular to the scattering plane, there is also a linear component. This means that, when measuring the hysteresis with linear polarization during a hysteresis cycle, the intensity will be an even function of the applied field when the change in the magnetic moment (and field) is confined within the scattering plane but becomes more complicated when the magnetic moment is out of the scattering plane. Furthermore, with circular polarization, the dependence of the scattered intensity on the moment is a combination of linear and quadratic. With the moment parallel to the scattering plane, the linear component changes with the helicity of the incident beam. Surprisingly, in stark contrast to absorption studies, even when the magnetic moment is perpendicular to the scattering plane there is still a dependence on the moment with a linear component. This linear component is completely independent of the helicity of the beam, meaning that the hysteresis loops will not be inverted with helicity. [ABSTRACT FROM AUTHOR]

Synchrotron light sources can provide the required spatial coherence, stability and control to support the development of advanced lithography at the extreme ultraviolet and soft X-ray wavelengths that are relevant to current and future fabricating technologies. Here an evaluation of the optical performance of the soft X-ray (SXR) beamline of the Australian Synchrotron (AS) and its suitability for developing interference lithography using radiation in the 91.8 eV (13.5 nm) to 300 eV (4.13 nm) range are presented. A comprehensive physical optics model of the APPLE-II undulator source and SXR beamline was constructed to simulate the properties of the illumination at the proposed location of a photomask, as a function of photon energy, collimation and monochromator parameters. The model is validated using a combination of experimental measurements of the photon intensity distribution of the undulator harmonics. It is shown that the undulator harmonics intensity ratio can be accurately measured using an imaging detector and controlled using beamline optics. Finally, the photomask geometric constraints and achievable performance for the limiting case of fully spatially coherent illumination are evaluated. [ABSTRACT FROM AUTHOR]

We analyse the X-ray spectrum of the black hole (BH) X-ray binary MAXI J1820 + 070 using observations from XMM-Newton and NuSTAR during 'hard' states of its 2018–2019 outburst. We take a fully Bayesian approach, and this is one of the first papers to present a fully Bayesian workflow for the analysis of an X-ray binary X-ray spectrum. This allows us to leverage the relatively well-understood distance and binary system properties (like inclination and BH mass), as well as information from the XMM-Newton RGS data to assess the foreground X-ray absorption. We employ a spectral model for a 'vanilla' disc-corona system: the disc is flat and in the plane perpendicular to the axis of the jet and the BH spin, the disc extends inwards to the innermost stable circular orbit around the BH, and the (non-thermal) hard X-ray photons are up-scattered soft X-ray photons originating from the disc thermal emission. Together, these provide tight constraints on the spectral model and, in combination with the strong prior information about the system, mean we can then constrain other parameters that are poorly understood such as the disc colour correction factor. By marginalizing over all the parameters, we calculate a posterior density for the BH spin parameter, a. Our modelling suggests a preference for low or negative spin values, although this could plausibly be reproduced by higher spins and a modest degree of disc truncation. This approach demonstrates the efficacy and some of the complexities of Bayesian methods for X-ray spectral analysis. [ABSTRACT FROM AUTHOR]

Multiaxial neutron/x-ray imaging and three-dimensional (3D) reconstruction techniques play a crucial role in gaining valuable insights into the generation and evolution mechanisms of pulsed radiation sources. Owing to the short emission time (∼200 ns) and drastic changes of the pulsed radiation source, it is necessary to acquire projection data within a few nanoseconds in order to achieve clear computed tomography 3D imaging. As a consequence, projection data that can be used for computed tomography image reconstruction at a certain moment are often available for only a few angles. Traditional algorithms employed in the process of reconstructing 3D images with extremely incomplete data may introduce significant distortions and artifacts into the final image. In this paper, we propose an iterative image reconstruction method using cylindrical harmonic decomposition and a self-supervised denoising network algorithm based on the deep image prior method. We augment the prior information with a 2D total variation prior and a 3D deep image prior. Single-wire Z-pinch imaging experiments have been carried out at Qin-1 facility in five views and four frames, with a time resolution of 3 ns for each frame and a time interval of 40 ns between adjacent frames. Both numerical simulations and experiments verify that our proposed algorithm can achieve high-quality reconstruction results and obtain the 3D intensity distribution and evolution of extreme ultraviolet and soft x-ray emission from plasma. [ABSTRACT FROM AUTHOR]

This work investigates the performance of the electrospray aerosol generator at the European X-ray Free Electron Laser (EuXFEL). This generator is, together with an aerodynamic lens stack that transports the particles into the X-ray interaction vacuum chamber, the method of choice to deliver particles for single-particle coherent diffractive imaging (SPI) experiments at the EuXFEL. For these experiments to be successful, it is necessary to achieve high transmission of particles from solution into the vacuum interaction region. Particle transmission is highly dependent on efficient neutralization of the charged aerosol generated by the electrospray mechanism as well as the geometry in the vicinity of the Taylor cone. We report absolute particle transmission values for different neutralizers and geometries while keeping the conditions suitable for SPI experiments. Our findings reveal that a vacuum ultraviolet ionizer demonstrates a transmission efficiency approximately seven times greater than the soft X-ray ionizer used previously. Combined with an optimized orifice size on the counter electrode, we achieve >40% particle transmission from solution into the X-ray interaction region. These findings offer valuable insights for optimizing electrospray aerosol generator configurations and data rates for SPI experiments. [ABSTRACT FROM AUTHOR]

This paper presents a compact source of soft X-ray radiation for operation in the wavelength range of 2–5 nm with a pulse repetition frequency of more than 500 Hz. The source parameters were optimized to reduce the intensity of ablation of the discharge volume wall and obtain the maximum intensity of the spectral lines of multicharged ions CV—4 nm and Ar IX—4.87 nm. The obtained results can be used in the development of a microscope for the tasks of cell transmission microscopy with nanometer resolution. [ABSTRACT FROM AUTHOR]

In this paper, we study the dynamics of heating the matrix of anode nodes membrane with a transmission-type target under the action of a field emission current generated in the electronic system of a maskless X-ray nanolithograph. The promising membrane materials that provide the most efficient heat removal from the matrix have been determined, among which diamond-like films have shown the best thermal stability. At the calculated power of soft X-ray radiation PX= 2.5 nW, scattered by a pixel with a size of 20 nm and an X-ray resist irradiation dose D = 100 J/m2, the exposure time was 25 µs. It is shown that during the exposure of a 150 mm plate, a diamond-like anode membrane with a size of 300 × 300 elements heats up from 20 to 62°C, which is 15–25 times lower than the heating temperature of alternative anode materials (Cu, Fe, Ni, Si, Al). The technological route for the fabrication of the matrix of anode nodes is described, taking into account the proposed methods for optimizing its design, aimed at reducing the thermal effects of heating during X-ray nanolithography processes. The results obtained can be applied in the development of a thermostable system of microfocus X-ray tubes as part of a maskless X-ray nanolithograph. [ABSTRACT FROM AUTHOR]

In this work, we present the results of the analysis performed with near edge absorption fine structure spectroscopy of barium edges in a B+BaF2 optical filter. The radiation was generated by a laser-plasma soft X-ray source based on a double-stream gas puff target. The use of a flat-field spectrometer based on a diffraction grating allowed us to collect the absorption spectra of the radiation transmitted by the analyzed optical filter. The results demonstrate the appearance of clear M-edges of barium (M4 and M5). [ABSTRACT FROM AUTHOR]

• A soft topological insulator system with imperfect interfaces is modeled. • Tunable phase transitions through finite deformation and adjusting imperfect interfaces' stiffness are studied. • Stiffness of soft imperfect interfaces under finite deformations is given. • Enhancing the stiffness of imperfect interfaces transfers the system from a resonance type to a dispersion type. Acoustic metamaterials, especially the topological insulators, have garnered substantial research attention due to their unique wave properties. Recent research emphasizes the crucial role of imperfect interfaces in accurately simulating and understanding wave propagation within these metamaterials. This paper studies the mechanical properties of soft imperfect interfaces and derives the effects of finite deformations on their stiffness. We present a comprehensive model of a soft Rayleigh beam system that incorporates these interfaces, allowing for the observation of the topological phase transition by altering the distance between them. Our investigation into the impacts of finite deformations and interface stiffness adjustment reveals that longitudinal waves' phase transition points are mainly influenced by interface stiffness. In contrast, transverse waves are predominantly affected by finite deformations. The decisive parameters driving these phenomena are also identified theoretically. The transmission studies of supercells further confirm the presence of topologically protected interface modes and their extensive tunability. Overall, this study offers a novel methodology and framework for managing topological phase transition in composite and soft topological insulator systems. This paper models a soft topological insulator system that integrates the Rayleigh beams with imperfect interfaces. Several methods are utilized to calculate the band structure. The topological phase diagrams are used to investigate the phase transition process. Finally, tunable topologically protected interface modes are studied. [Display omitted] [ABSTRACT FROM AUTHOR]

The Soochow University Beamline, located at the National Synchrotron Radiation Laboratory in China, is a Soft X-ray beamline designed for studying energy-related materials and devices. It operates in the energy range of 45 eV–1100 eV and is specifically tailored for investigating Li, B, C, N, O, F K-edges, and most L-edges of transition metals. The beamline offers various capabilities, including X-ray absorption, photon in photon out, and in situ/operando studies of energy materials and devices in gas/liquid environments. It has been successful in producing high-quality research papers and is open to users worldwide. The beamline is a collaborative effort between Soochow University and the National Synchrotron Radiation Laboratory, with funding from Soochow University. It is the first synchrotron radiation beamline in China to be funded by a university. [Extracted from the article]

• Resonant soft x-ray reflectometry 2D maps are modeled for iron oxide multilayers. • Iron oxidation from top/bottom side can be distinguished by reflectance 2D patterns. • Polymorphic Fe 2 O 3 multilayers can be uniquely identified by interference signatures. In the present paper we discuss applicability of the synchrotron method of resonant x-ray reflectometry to non-destructive depth profiling of multilayer heterostructures with low optical contrast between the sublayers. The two-dimensional mapping approach comprising evaluation and measurement of reflectance as a function of photon energy and grazing angle is shown to provide a convenient way to effectively utilize the enhancement of optical contrast between the sublayers that exists at the absorption edges of chemical elements due to particular spectral shape peculiarities related to oxidation state, crystallographic environment and magnetization. In the present study the evaluation of the resonant X-ray reflectivity maps is performed using a specially developed modeling and fitting software. Estimation of the photon energy / grazing angle combinations at which the reflectance is most sensitive to the minor changes in the physical properties of the sublayers is illustrated by the example of ferroic-on-semiconductor nanoscale heterostructures composed of nanoscale film of metallic iron oxidized from either top or bottom side. The subtle differences in resonant soft x-ray reflectance caused by variation of the oxide film thickness, oxidation state and crystallographic environment are discussed. The presented approach is applicable to a large class of heterostructures composed of sublayers that can be distinguished only by the differences in their near edge X-ray absorption fine structure. [ABSTRACT FROM AUTHOR]

EUV light optics are either reflective or diffractive due to the substantial absorption characteristics by almost all materials. Despite great successes in manufacturing integrated circuit chips, reflective EUV optics are still unfriendly to small-to-medium enterprise (SME) because of the enormous costs. Recently, diffractive EUV optics has come to the light in hopes to be able to establish manufacturing nanoscale products and inspecting nanoscale structures. Diffractive zone plates with high resolution in EUV wavelengths are urgently needed. This paper reports our latest success in developing 20 nm resolution zone plates for focusing and imaging in the EUV and soft X-ray regions. It firstly discusses the diffraction efficiency of FZPs tailored for 13.5 nm wavelength to decide the essential height of the zone plate. Then, Monte Carlo simulation method was used to figure out the achievable zone plate parameters by high-resolution electron beam lithography (EBL). Finally, this work systematically explored the viability of nanofabricating top-tier 20 nm resolution hydrogen silsesquioxane (HSQ) zone plates with the duty cycle ratio nearing 1:1 and the aspect ratio approaching 13:1 on 50 nm thick Si 3 N 4 membranes. [Display omitted] • 20 nm resolution Fresnel zone plates (FZPs) for EUV were successfully fabricated. • 50-nm thick silicon nitride substrate can improve FZPs' diffraction efficiency. • Hydrogen silsesquioxane (HSQ) FZPs only require a one-step exposure process. • Simulated and experimental results show the 20-nm designed width is the optimal. [ABSTRACT FROM AUTHOR]

The origin of X-ray emission from the resolved kiloparsec-scale jets and hotspots of many active galactic nuclei remains uncertain, particularly where the X-ray emission is separate from the radio-optical synchrotron component. Possible explanations include synchrotron emission from a second electron population and external Compton or synchrotron self-Compton processes—alternatives which imply very different physical conditions within the jet. Until recently, X-ray studies of resolved jets and hotspots have been restricted to below ∼10 keV, often showing a hard spectral index indicating a spectral peak beyond this energy range. Here we present NuSTAR observations of the nearby powerful radio galaxy Pictor A, in which we clearly detect the western hotspot at approximately 4′ from the host galaxy, the most significant detection of hotspot emission above 10 keV to date. The NuSTAR spectrum is best fit by a single power law of index Γ = 2.03 ± 0.04; an exponential cutoff gives a 1 σ lower limit on the cutoff energy of 40.7 keV. We confirm previous findings of variations in the soft X-ray flux detected by Chandra over the 2000 to 2015 period, at a significance of 6.5 σ. This rises to >8 σ in the common 3–8 keV band using the combined 22 yr span of Chandra and NuSTAR observations. The variability of the western Pictor A hotspot strongly confirms the previously argued synchrotron nature of the X-ray emission for the hotspot, while the lower bound to the spectral cutoff energy implies electron energies in the hotspot reach up to at least a few TeV. [ABSTRACT FROM AUTHOR]

A fraction of the active supermassive black holes at the centers of galaxies in our Universe are capable of launching extreme kiloparsec-long relativistic jets. These jets are known multiband (radio to γ-ray) and multimessenger (neutrino) emitters, and some of them have been monitored over decades at all accessible wavelengths. However, several open questions remain unanswered about the processes powering these highly energetic phenomena. These jets intrinsically produce soft-to-hard X-ray emission that extends from E > 0.1 keV up to E > 100 keV, and simultaneous broadband X-ray coverage, combined with excellent timing and imaging capabilities, is required to uncover the physics of jets. Indeed, truly simultaneous soft-to-hard X-ray coverage, in synergy with current and upcoming high-energy facilities (such as IXPE, COSI, CTAO, etc.) and neutrino detectors (e.g., IceCube), would enable us to disentangle the particle population responsible for the high-energy radiation from these jets. A sensitive hard X-ray survey (F20-80 keV < 10-15erg cm-2 s-1) could unveil the bulk of their population in the early Universe. Acceleration and radiative processes responsible for the majority of their X-ray emission would be pinned down by microsecond timing capabilities at both soft and hard X-rays. Furthermore, imaging jet structures for the first time in the hard X-ray regime could unravel the origin of their high-energy emission. The proposed Probe-class mission concept High Energy X-ray Probe (HEX-P) combines all these required capabilities, making it the crucial next-generation X-ray telescope in the multi-messenger, time-domain era. HEX-P will be the ideal mission to unravel the science behind the most powerful accelerators in the Universe. [ABSTRACT FROM AUTHOR]

Recently developed sixth-order wave aberration expressions of soft X-rays and a vacuum ultraviolet optical system are first extended to plane-symmetric refractive optical systems, and then, applying the transformation relations between plane-symmetric and paraxial refractive optical system, the sixth-order intrinsic and extrinsic wave aberration coefficient expressions of a paraxial refractive optical system are derived. In addition, the corresponding fifth-order aberration expressions are also obtained. Finally, the resultant aberration expressions are applied to calculate the aberration on the image plane of one design example of a paraxial refractive optical system with a large aperture, and these calculation results are compared with ones obtained by ray-tracing software Zemax to prove that they have satisfactory calculation accuracy. [ABSTRACT FROM AUTHOR]

We report for the first time the detection of thermal free–free emission from post-flare loops at 34 GHz in images from the Nobeyama Radioheliograph. We studied eight loops, seven of which were from regions with an extremely strong coronal magnetic field reported by Fedenev et al. Loop emission was observed in a wide range of wavelength bands, up to soft X-rays, confirming their multitemperature structure and was associated with noise storm emission in metric λ. The comparison of the 17 GHz emission with that at 34 GHz, after a calibration correction of the latter, showed that the emission was optically thin at both frequencies. We describe the structure and evolution of the loops and we computed their density, obtaining values for the top of the loops between 1 and 6 × 1010 cm−3, noticeably varying from one loop to another and in the course of the evolution of the same loop system; these values have only a weak dependence on the assumed temperature, 2 × 106 K in our case, as we are in the optically thin regime. Our density values are above those reported from EUV observations, which go up to about 1010 cm−3. This difference could be due to the fact that different emitting regions are sampled in the two domains and/or due to the more accurate diagnostics in the radio range, which do not suffer from inherent uncertainties arising from abundances and non-LTE excitation/ionization equilibria. We also estimated the magnetic field in the loop tops to be in the range of 10–30 G. [ABSTRACT FROM AUTHOR]

The dynamics of Earth's magnetopause, driven by several different external/internal physical processes, plays a major role in the geospace energy budget. Given magnetopause motion couples across many space plasma regions, numerous forms of observations may provide valuable information in understanding these dynamics and their impacts. In-situ multi-point spacecraft measurements measure the local plasma environment, dynamics and processes; with upcoming swarms providing the possibility of improved spatiotemporal reconstruction of dynamical phenomena, and multi-mission conjunctions advancing understanding of the "mesoscale" coupling across the geospace "system of systems." Soft X-ray imaging of the magnetopause should enable boundary motion to be directly remote sensed for the first time. Indirect remote sensing capabilities might be enabled through the field-aligned currents associated with disturbances to the magnetopause; by harnessing data from satellite mega-constellations in low-Earth orbit, and taking advantage of upgraded auroral imaging and ionospheric radar technology. Finally, increased numbers of closely-spaced ground magnetometers in both hemispheres may help discriminate between high-latitude processes in what has previously been a "zone of confusion." Bringing together these multiple modes of observations for studying magnetopause dynamics is crucial. These may also be aided by advanced data processing techniques, such as physics-based inversions and machine learning methods, along with comparisons to increasingly sophisticated geospace assimilative models and simulations. [ABSTRACT FROM AUTHOR]

Stellar-mass black holes in x-ray binary systems are powered by mass transfer from a companion star. The accreted gas forms an accretion disk around the black hole and emits x-ray radiation in two distinct modes: hard and soft state. The origin of the states is unknown. We perform radiative plasma simulations of the electron-positron-photon corona around the inner accretion flow. Our simulations extend previous efforts by self-consistently including all the prevalent quantum electrodynamic processes. We demonstrate that when the plasma is turbulent, it naturally generates the observed hard-state emission. In addition, we show that when soft x-ray photons irradiate the system—mimicking radiation from an accretion disk—the turbulent plasma transitions into a new equilibrium state that generates the observed soft-state emission. Our findings demonstrate that turbulent motions of magnetized plasma can power black-hole accretion flow coronae and that quantum electrodynamic processes control the underlying state of the plasma. Physical origin of accretion states in black hole X-ray binary systems is an open question. Here, the authors perform self-consistent radiative plasma simulations of the corona around the inner accretion flow and demonstrate natural generation of the observed hard and soft state X-ray emission when the plasma is turbulent. [ABSTRACT FROM AUTHOR]

The BL Lacertae (BL Lac) object OJ 287 underwent an intense X-ray activity phase, exhibiting its brightest recorded X-ray flare in 2016–2017, characterized by much softer X-ray spectra and, concurrently, its first-ever recorded very-high-energy (VHE) emission (100–560 GeV), reported by the VERITAS observatory. Broadband spectral energy distribution reveals a new jet emission component similar to high-synchrotron-peaked BL Lac objects, thereby implying the soft X-ray spectrum for the synchrotron emission. Using the advantage of simultaneous X-ray and VHE spectral information, as well as the source being a low-synchrotron-peaked BL Lac object, we systematically explored the extragalactic background light (EBL) spectrum by demanding that the VHE spectrum cannot be harder than the X-ray spectrum. We used three different phenomenological forms of the EBL spectral shape (power-law, parabola, and polynomial) motivated by current constraints on the EBL with the Bayesian Monte Carlo approach to infer the credible EBL range. Our study favors an almost flat power-law spectral shape and is consistent with previous studies. The other spectral forms capable of capturing curvature though result in a better statistics value; the improvement is statistically insignificant given the additional parameters. [ABSTRACT FROM AUTHOR]

In this paper, we propose a novel soft origami tripod structure and mechanism capable of multimodal motions based on electrohydraulic actuators. The tripod structure consists of top and bottom plates connected by three origami legs in parallel. The three electrohydraulic actuators are located at the connecting points between the bottom plate and legs. The actuators are independently swelled by the applied voltage and utilized for extending the soft legs from unfolding. A high degree of freedom (DOF) of the tripod is realized by applying the classic origami pattern waterbomb to the legs, which serve as a spherical joint. The soft tripod has linear and tilting motions while the legs are stretched by independently operated actuators. Basically, the three extended legs achieve linear movement of the top plate. When only one leg is straightened, the other legs become asymmetrical and cause the tripod to tilt. The structure exhibits a linear strain of 122.15% and a tilting angle of 22.25°. In addition, we predict the trajectory of the tripod structure via kinematic modeling and analyze the results based on validation. As a result, the soft origami tripod using electrohydraulic actuators is scalable and controllable with the advantages of multimodal motion and light structure. [Display omitted] • Soft origami tripod had multimodal motions based on electrohydraulic actuators. • Actuators simultaneously utilized electrostatic force and hydraulic pressure. • Tripod structure comprised three origami legs connecting top and bottom plates. • Each leg was self-unfolding by actuator, which could control position of top plate. • Tripod exhibited a linear strain of 122.15% and tilting angle of 22.25°. [ABSTRACT FROM AUTHOR]

Although sodium‐ion batteries (SIBs) offer promising low‐cost alternatives to lithium‐ion batteries (LIBs), several challenges need to be overcome for their widespread adoption. A primary concern is the optimization of carbon anodes. Graphite, vital to the commercial viability of LIBs, has a limited capacity for sodium ions. Numerous alternatives to graphite are explored, particularly focusing on disordered carbons, including hard carbon. However, compared with graphite, most of these materials underperform in LIBs. Furthermore, the reaction mechanism between carbon and sodium ions remains ambiguous owing to the structural diversity of disordered carbon. A straightforward mechanical approach is introduced to enhance the sodium ion storage capacity of graphite, supported by comprehensive analytical techniques. Mechanically activated graphite delivers a notable reversible capacity of 290.5 mAh·g−1 at a current density of 10 mA·g−1. Moreover, it maintains a capacity of 157.7 mAh·g−1 even at a current density of 1 A·g−1, benefiting from the defect‐rich structure achieved by mechanical activation. Soft X‐ray analysis revealed that this defect‐rich carbon employs a sodium‐ion storage mechanism distinct from that of hard carbon. This leads to an unexpected reversible reaction on the solid electrolyte surface. These insights pave the way for innovative design approaches for carbon electrodes in SIB anodes. [ABSTRACT FROM AUTHOR]

In nature, coenzyme-independent oxidases have evolved in selective catalysis using isolated substrate-binding pockets. Single-atom nanozymes (SAzymes), an emerging type of non-protein artificial enzymes, are promising to simulate enzyme active centers, but owing to the lack of recognition sites, realizing substrate specificity is a formidable task. Here we report a metal-ligand dual-site SAzyme (Ni-DAB) that exhibited selectivity in uric acid (UA) oxidation. Ni-DAB mimics the dual-site catalytic mechanism of urate oxidase, in which the Ni metal center and the C atom in the ligand serve as the specific UA and O2 binding sites, respectively, characterized by synchrotron soft X-ray absorption spectroscopy, in situ near ambient pressure X-ray photoelectron spectroscopy, and isotope labeling. The theoretical calculations reveal the high catalytic specificity is derived from not only the delicate interaction between UA and the Ni center but also the complementary oxygen reduction at the beta C site in the ligand. As a potential application, a Ni-DAB-based biofuel cell using human urine is constructed. This work unlocks an approach of enzyme-like isolated dual sites in boosting the selectivity of non-protein artificial enzymes. Single-atom nanozymes are a type of non-protein artificial enzymes and promising for mimicking enzyme active centers, but lack recognition sites to confer substrate specificity. Here, the authors report on a metal-ligand dual-site single-atom nanozyme (Ni-DAB) that mimics the dual-site catalytic mechanism of urate oxidase and has high selectivity in uric acid (UA) oxidation. [ABSTRACT FROM AUTHOR]

We explore the impact of initial state soft gluon radiations on the azimuthal angle asymmetries in photo-production of hard di-jet via coherent diffraction in ultraperipheral heavy ion collisions, as well as in electron-proton (ep) and electron-nucleus (eA) collisions. The primary production mechanism is identified as the diffractive production of two hard jets, accompanied by a collinear gluon emission along the beam direction. In contrast, the diffractive exclusive di-jet production, where the initial state radiation is absent, is suppressed due to color transparency. Our analysis shows that azimuthal asymmetries, traditionally attributed to final state gluon emissions, are reduced by the presence of initial state radiations. The sensitivity of azimuthal asymmetries to both initial and final state radiations suggests that they could provide novel insights into the mechanisms of di-jet production in diffractive processes. [ABSTRACT FROM AUTHOR]

Pulsar halos (also termed "TeV halos") are a new class of γ -ray sources in the Galaxy, which manifest as extended γ -ray emission around middle-aged pulsars, as discovered around the Geminga pulsar, the Monogem pulsar, and PSR J0622+3749 by the High-Altitude Water Cherenkov Observatory and the Large High-Altitude Air Shower Observatory. A consensus has been reached that the teraelectronvolt emission comes from the inverse Compton scattering of escaping electrons/positrons from the pulsar wind nebula of the soft background radiation field, while the particle transport mechanism in the halo is still in dispute. Currently, there are mainly three interpretations: the isotropic, suppressed diffusion model; the isotropic, unsuppressed diffusion model that considers the ballistic propagation of newly injected particles; and the anisotropic diffusion model. While the predicted γ -ray surface brightness profiles of all three models can be more or less consistent with the observations, the implications of the three models for cosmic-ray transport mechanisms and the properties of the interstellar magnetic field are quite different. In this study, we calculate the anticipated X-ray emission of pulsar halos under the three models. We show that the synchrotron radiation of these escaping electrons/positrons can produce a corresponding X-ray halo around the pulsar and that the expected surface brightness profiles are distinct in the three models. We suggest that sensitive X-ray detectors of a large field of view (such as eROSITA and the Einstein Probe) with a reasonably long exposure time are crucial to understanding the formation mechanism of pulsar halos and can serve as a probe of the properties of interstellar turbulence. [ABSTRACT FROM AUTHOR]

A fundamental goal of modern-day astrophysics is to understand the connection between supermassive black hole (SMBH) growth and galaxy evolution. Merging galaxies offer one of the most dramatic channels for galaxy evolution known, capable of driving inflows of gas into galactic nuclei, potentially fueling both star formation and central SMBH activity. Dual active galactic nuclei (dual AGNs) in late-stage mergers with nuclear pair separations <10 kpc are thus ideal candidates to study SMBH growth along the merger sequence since they coincide with the most transformative period for galaxies. However, dual AGNs can be extremely difficult to confirm and study. Hard X-ray (>10 keV) studies offer a relatively contamination-free tool for probing the dense obscuring environments predicted to surround the majority of dual AGN in late-stage mergers. To date, only a handful of the brightest and closest systems have been studied at these energies due to the demanding instrumental requirements involved. We demonstrate the unique capabilities of HEX-P to spatially resolve the soft and -- for the first time -- hard X-ray counterparts of closely-separated (~2" -- 5") dual AGNs in the local Universe. By incorporating physically-motivated obscuration models, we reproduce realistic broadband X-ray spectra expected for deeply embedded accreting SMBHs. Hard X-ray spatially resolved observations of dual AGNs -- accessible only to HEX-P -- wiU hence transform our understanding of dual AGN in the nearby Universe. [ABSTRACT FROM AUTHOR]

Background: Post-radiation fractures are a significant complication of cancer treatment, often being challenging to manage and impacting patients' quality of life. This study systematically reviews the literature on fractures in irradiated bones, focusing on risk factors, treatment modalities, and prevention strategies. Factors increasing fracture risk include exposure to high doses of radiation of at least 50 Gy, female gender, menopausal age, and periosteal stripping. Additionally further risk factors are the size of the original tumor and osteoporosis. Methods: A search of PubMed yielded 541 articles, with 4 were ultimately included in the review. These retrospective studies focused on patients undergoing Combined Limb-Sparing Surgery and Radiation Therapy for soft tissue sarcoma. Results: Results show post-radiation fractures affect approximately 4% of patients, with the femur being the most frequently affected site. Intramedullary nailing emerges as the gold standard treatment, with prosthetic replacement or megaprostheses used in the metaepiphyseal region and as salvage procedures. Non-union and infection remain formidable complications. Conclusions: This study highlights the importance of prophylactic nailing in fracture prevention and the efficacy of free vascularized fibular flaps to achieve bone union during revision surgeries. Limited case availability and patient follow-up hinder comprehensive studies, impacting treatment outcomes. [ABSTRACT FROM AUTHOR]

Ni–Fe‐based oxides are among the most promising catalysts developed to date for the bottleneck oxygen evolution reaction (OER) in water electrolysis. However, understanding and mastering the synergy of Ni and Fe remain challenging. Herein, we report that the synergy between Ni and Fe can be tailored by crystal dimensionality of Ni, Fe‐contained Ruddlesden–Popper (RP)‐type perovskites (La0.125Sr0.875)n+1(Ni0.25Fe0.75)nO3n+1 (n = 1, 2, 3), where the material with n = 3 shows the best OER performance in alkaline media. Soft X‐ray absorption spectroscopy spectra before and after OER reveal that the material with n = 3 shows enhanced Ni/Fe–O covalency to boost the electron transfer as compared to those with n = 1 and n = 2. Further experimental investigations demonstrate that the Fe ion is the active site and the Ni ion is the stable site in this system, where such unique synergy reaches the optimum at n = 3. Besides, as n increases, the proportion of unstable rock‐salt layers accordingly decreases and the leaching of ions (especially Sr2+) into the electrolyte is suppressed, which induces a decrease in the leaching of active Fe ions, ultimately leading to enhanced stability. This work provides a new avenue for rational catalyst design through the dimensional strategy. [ABSTRACT FROM AUTHOR]

The flexible distribution network presents a promising architecture to accommodate highly integrated distributed generators and increasing loads in an efficient and cost-effective way. The distribution network is characterised by flexible interconnections and expansions based on soft open points, which enables it to dispatch power flow over the entire system with enhanced controllability and compatibility. Herein, we propose a multi-resource dynamic coordinated planning method of flexible distribution network that allows allocation strategies to be determined over a long-term planning period. Additionally, we establish a probabilistic framework to address source-load uncertainties, which mitigates the security risks of voltage violations and line overloads. A practical distribution network is adopted for flexible upgrading based on soft open points, and its cost benefits are evaluated and compared with that of traditional planning approaches. By adjusting the acceptable violation probability in chance constraints, a trade-off between investment efficiency and operational security can be realised. Flexible distribution networks with soft open points present a promising way to accommodate distributed generators and increasing loads. Here, authors present a multi-resource dynamic coordinated planning method, allowing allocation strategies to be determined over long-term planning periods. [ABSTRACT FROM AUTHOR]

The interplay of electron-electron and electron-lattice interactions plays an important role in determining exotic properties in strongly correlated electron systems. Of particular interest is quasi-one-dimensional SrNbOx metals, which are perovskite-related layered Carpy-Galy phases. Quasi-one-dimensional metals often exhibit a charge density wave (CDW) accompanied by lattice distortion; however, to date, the presence of a CDW in a quasi-one-dimensional metallic Carpy-Galy phase has not been detected. Here, we report the discovery of two distinct and simultaneous commensurate CDWs in Sr0.95NbO3.37 using resonant soft X-ray scattering (RSXS), namely, an electronic-(001) superlattice below ~ 200 K and an electronic-(002) Bragg peak. We also observe a non-electronic-(002) Bragg peak showing lattice distortion below ~ 150 K. Through the temperature dependence and resonance profile of these CDWs and the lattice distortion, as well as the relationship between the wavelength and charge density, these CDWs are determined to be Wigner crystals and Peierls-like instabilities, respectively. The electron‒electron interaction is strong and dominant even up to 350 K, and upon cooling, it drives the electron–lattice interaction. The correlation length of the electronic-(001) superlattice is surprisingly larger than that of the electronic-(002) Bragg peak, and the superlattice is highly anisotropic. Supported by theoretical calculations, the CDWs are determined by the charge anisotropy and redistribution between the O-2p and Nb-4d orbitals, and the strength of the electronic-(001) superlattice is within the strong coupling limit. Groundbreaking Discovery: Electron–Electron Interaction Dominates in Sr0.95NbO3.37 Understanding how electrons interact in materials is vital for fundamental research and creating new technologies. However, the connection between different CDWs and their impact on materials, particularly inorganic systems, is unclear. The study, led by Andrivo Rusydi, aimed to understand CDWs in a specific crystal type, a quasi-one-dimensional metal. Rusydi and his team used resonant soft X-ray scattering to identify two distinct CDWs in one crystal. Their results showed that the Wigner crystal appeared without any crystal structure changes, while the Peierls-like instability was associated with a crystal distortion. These findings suggest that strong electron-electron interactions can drive changes in the crystal lattice, leading to different CDWs. This research offers new insights into the complex relationship between electron interactions and CDWs in inorganic materials. The advancements made in this study could impact future electronic devices development and understanding superconductivity. This summary was initially drafted using artificial intelligence, then revised and fact-checked by the author. The interplay of electron-electron and electron-lattice interactions plays an important role in determining exotic properties in strongly correlated electron systems. Here, we report the discovery of two distinct and simultaneous commensurate CDWs, Wigner crystal and Peierls-like instabilities, in Sr0.95NbO3.37 using resonant soft X-ray scattering. These CDWs arise from charge anisotropy and redistribution in Nb 4d – O 2p hybridization and influence transport and optical gaps. The strength of Wigner crystal is within the strong coupling limit. This study paves the way for utilizing RSXS to distinguish CDWs and calls for further investigation of electron‒electron and electron–lattice interactions in inorganic systems [ABSTRACT FROM AUTHOR]