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The X-ray satellite “Einstein Probe” of the Chinese Academy of Sciences (CAS) was successfully launched on 9 January 2024 at 15:03 Beijing Time from the Xichang Satellite Launch Center in China with a “Long March-2C” rocket. The Einstein Probe is equipped with two scientific X-ray telescopes. One is the Wide-field X-ray Telescope (WXT), which uses lobster-eye optics. The other is the Follow-up X-ray Telescope (FXT), a Wolter-I type telescope. These telescopes are designed to study the universe for high-energy X-rays associated with transient high-energy phenomena. The FXT consists of two modules based on 54 thin X-ray Wolter-I grazing incidence Ni-replicated mirrors produced by the Italian Media Lario company, as contributions from the European Space Agency and the Max Planck Institute for Extraterrestrial Physics (MPE), which also provided the focal-plane detectors. Meanwhile, the Institute of High Energy Physics (IHEP), together with the Harbin Institute of Technology and Xi’an Institute of Optics and Precision Mechanics, has also completed the development and production of the structural and thermal model (STM), qualification model (QM) and flight model (FM) of FXT mirrors for the Einstein Probe (EP) satellites for demonstration purposes. This paper introduces the precision manufacturing adopted in China of Wolter-I X-ray mirror mandrels similar to those used for the EP-FXT payload. Moreover, the adopted electroformed nickel replication process, based on a chemical nickel–phosphorus alloy, is reported. The final results show that the surface of the produced mandrels after demolding and the internal surface of the mirrors have been super polished to the roughness level better than 0.3 nm RMS and the surface accuracy is better than 0.2 μm, and the mirror angular resolution for single mirror shells may be as good as 17.3 arcsec HPD (Half Power Diameter), 198 arcsec W90 (90% Energy Width) @1.49 keV (Al-K line). These results demonstrate the reliability and advancement of the process. As the first efficient X-ray-focusing optics manufacturing chain established in China, we successfully developed the first focusing mirror prototype that could be used for future X-ray satellite payloads.

The reactions between MoS 2 and several metallic powders, including Ni, Al, and Ni 3 Al, were studied by differential scanning calorimetry (DSC) and X-ray diffraction (XRD). The DSC results revealed that MoS 2 started to react with Ni and Al at 630 and 560 °C, respectively, but did not react with Ni 3 Al even at 1200 °C. The XRD results indicated that the reaction products of MoS 2 and Ni were a series of new sulfides and molybdenum compounds, including Ni 3 S 2 , Ni 7 S 6 , and Ni 4 Mo, and those of MoS 2 and Al were Al 2 S 3 and various aluminides. Additionally, the compositions of the products varied with the reaction temperature. Because these new sulfides did not possess self-lubricating properties, the consumption of MoS 2 should be avoided. According to these reactions, a synthetic route for the Ni 3 Al/MoS 2 composite using Ni, Al, and MoS 2 composite powders was proposed and demonstrated. During the synthesis process, the composite powders were first compressed under a pressure of 180 MPa. The resulting green compacts were heated to 500 °C with a heating rate of 20 °C/min, and then to 530 °C with a heating rate of 1 °C/min. The holding time at 530 °C was 4 h. The phase composition and microstructure of the as-synthesized composite were studied by XRD and SEM. The results showed that MoS 2 remained stable during the synthesis process. Friction and wear tests demonstrated that the composite exhibited good self-lubricating properties with a low friction coefficient of about 0.2 and a small wear rate of 1.04 × 10 − 5  mm 3  N − 1  m − 1 .

Reflectivity is a key topic in soft X-ray optics research and serves as the foundation for studying the performance of the optics for X-ray astronomical satellites. Since its establishment, the 100-m X-ray Test Facility (100XF) has been continuously developing various testing functionalities, including calibration of timing, imaging, and energy response. This paper provides a detailed description of the X-ray optics reflectivity test method based on the 100XF, which can be applied to various grazing incident X-ray optics, including Wolter-I and lobster-eye types, significantly expanding the application scope of the 100XF. A flat mirror sample (SiO 2 coated on a Si wafer) is tested. Results of the variation of reflectivity with angle @ C-K α (0.28 keV), Al-K α (1.49 keV), and Ti-K α (4.50 keV) are presented in the description. The reflectivity test method has also been applied to the coating reflectivity study of the enhanced X-ray Timing and Polarimetry Mission (eXTP) mirror. At the same time, a new method utilizing the continuum spectrum of bremsstrahlung was carried out to study the continuous variation of reflectivity with energy, greatly improving efficiency compared to traditional methods, and all the results show a good agreement with the theoretical values. The deviation between the test and theoretical values in the low-energy range (1.5-8.0 keV) is less than 10%.

The Einstein Probe (EP) mission is a science mission designed for the time domain astronomy, which is approved by the Chinese Academy of Sciences (CAS) in 2017 and is to be launched in 2023 with a duration time of more than 3 years. The Follow-up X-ray Telescope (FXT) is an important payload onboard EP, which employs the Wolter I focusing mirror as the X-ray collection unit and the PNCCD as the focal plane detector. The Phase C study has been finished in 2021. During the Phase C, the structural and thermal model (STM) of the mirror assembly of FXT, provided by the European Space Agency (ESA), a mirror assembly developed by the Institute of High Energy Physics (IHEP), a qualification model (QM) PNCCD and other components, are integrated and tested in IHEP. All optical performances meet the goal requirement of EP, such as the field of view of 60 arcmins, the angular resolution of less than 30 arcsec HEW on-axis, and the focal length of ab. 1600 mm. After that, the FXT is assembled, integrated, and tested on the EP satellite platform. Furthermore, these performances are not changed after the mechanical and thermal tests on the spacecraft platform.

To fabricate high-quality polycrystalline VO2 thin film with a metal–insulator transition (MIT) temperature less than 50 °C, high-power impulse magnetron sputtering with different discharge currents was employed in this study. The as-deposited VO2 films were characterized by a four-point probe resistivity measurement system, visible-near infrared (IR) transmittance spectra, X-ray diffraction (XRD), X-ray photoelectron spectroscopy (XPS), and scanning electron microscopy. The resistivity results revealed that all the as-deposited films had a high resistance change in the phase transition process, and the MIT temperature decreased with the increased discharge current, where little deterioration in the phase transition properties, such as the resistance and transmittance changes, could be found. Additionally, XRD patterns at various temperatures exhibited that some reverse deformations that existed in the MIT process of the VO2 film, with a large amount of preferred crystalline orientations. The decrease of the MIT temperature with little deterioration on phase transition properties could be attributed to the reduction of the preferred grain orientations.

Loess slopes with steep gradients are particularly prone to vertical tension cracks at the crest, resulting from unloading and other factors. These cracks significantly affect the spatiotemporal distribution of moisture infiltration during rainfall, potentially leading to slope instability. This study investigates the impact of crest-tension cracks on moisture infiltration in loess slopes under extreme rainfall conditions, focusing on crack position, depth, and width. Soil moisture content and the dynamics of wetting fronts were monitored to assess how these tension cracks influence infiltration patterns. The results indicate that tension cracks at the slope crest act as preferential infiltration pathways, causing water retention within the cracks and forming a “U-shaped” preferential infiltration zone. The extent of this “U-shaped” wetting front is influenced by the crack’s width, depth, and proximity to the slope shoulder; wider, deeper cracks closer to the shoulder result in a more pronounced wetting front. Over time, as rainfall persists, the influence of preferential infiltration decreases, and the infiltration patterns of slopes with crest cracks begin to resemble those of homogeneous slopes. In both cases, wetting fronts exhibit intersecting patterns: one parallel to the slope crest and the other parallel to the slope surface. During the initial stages of rainfall, the migration speed of wetting fronts in slopes with crest-tension cracks was significantly higher than in homogeneous slopes. However, after prolonged rainfall, the migration speeds of wetting fronts in both scenarios converged. A strong linear correlation was observed between the average migration depth of the horizontal wetting front at the slope crest and the parallel wetting front on the slope surface, for both slope types. These findings deepen our understanding of moisture migration dynamics in loess slopes with crest-tension cracks, providing insights for developing effective slope hazard mitigation strategies.

Background Hutchinson–Gilford progeria syndrome (HGPS) is a rare genetic disorder characterized by accelerated aging, impaired growth, disrupted lipid metabolism, and reduced lifespan. Methods Prior research has primarily focused on cardiovascular manifestations, our research sheds light on multiple organs that underwent significant age-related changes validated by tissue cross-sections H&E, Masson's trichrome, and β-galactosidase staining. Results Among these pathologies tissues, the lung was severely affected and substantiated by clinical data of pulmonary anomalies from our HGPS patients. Biochemical and histological analyses of lung tissue from the HGPS mouse model revealed elevated Progerin expression, abnormal NAD metabolism, cellular senescence markers (higher level of p16 and p27, lower level of ki67), and various age-related morphology changes, including fibrosis, inflammation, and thickening of alveolar walls. Transcriptomic analyses of lung tissue indicated that down-regulated genes ( Thy1 , Tnc , Cspg4 , Ccr1 ) were associated with extracellular space, immune response, calcium signaling pathway, osteoclast differentiation, and lipid binding pathway. Conclusions This study unveiled the previously overlooked organs involved in HGPS pathogenesis and suggested a specific emphasis on the lung. Our findings suggest that pulmonary abnormalities may contribute to disease progression, warranting further investigation into their role in HGPS monitoring and management. Graphical abstract

Objective Evidence of therapy for dysfunctional coronary circulation in patients with ST-segment elevation myocardial infarction (STEMI) undergoing primary percutaneous coronary intervention (pPCI) is limited. This study was performed to compare the effects of atorvastatin and rosuvastatin on dysfunctional coronary circulation. Methods This retrospective study enrolled 597 consecutive patients with STEMI who underwent pPCI in 3 centers from June 2016 to December 2019. Dysfunctional coronary circulation was defined by the thrombolysis in myocardial infarction (TIMI) grade and the TIMI myocardial perfusion grade (TMPG). Logistic regression analysis was used to evaluate the impact of different statin types on dysfunctional coronary circulation. Results The incidence of TIMI no/slow reflow did not differ between the two groups, but the incidence of TMPG no/slow reflow was significantly lower in the atorvastatin than rosuvastatin group (44.58% vs. 57.69%, respectively). After multivariate adjustment, the odds ratio with 95% confidence interval of rosuvastatin was 1.72 (1.17–2.52) for after pretreatment TMPG no/slow reflow and 1.73 (1.16–2.58) for after stenting TMPG no/slow reflow. Atorvastatin and rosuvastatin showed no significant differences in clinical outcomes during hospitalization. Conclusions Compared with rosuvastatin, atorvastatin was associated with better coronary microcirculatory perfusion in patients with STEMI who underwent pPCI.

Tree species recognition accuracy greatly affects forest remote sensing mapping and forestry resource monitoring. The multispectral and texture features of the remote sensing images from the ZiYuan-3 (ZY-3) satellite at two phenological phases of autumn and winter (September 29th and December 7th) were selected for constructing and optimizing sensitive spectral indices and texture indices. Multidimensional cloud model and support vector machine (SVM) model were constructed by the screened spectral and texture indices for remote sensing recognition of Quercus acutissima ( Q. acutissima ) and Robinia pseudoacacia ( R. pseudoacacia ) on Mount Tai. The results showed that, the correlation intensities of the constructed spectral indices with tree species were preferable in winter than in autumn. The spectral indices constructed by band 4 showed the superior correlation compared with other bands, both in the autumn and winter time phases. The optimal sensitive texture indices for both phases were mean, homogeneity and contrast for Q. acutissima , and contrast, dissimilarity and second moment for R. pseudoacacia. Spectral features were found to have a higher recognition accuracy than textural features for recognizing on both Q. acutissima and R. pseudoacacia, and winter showing superior recognition accuracy than autumn, especially for Q. acutissima. The recognition accuracy of the multidimensional cloud model (89.98%) does not show a superior advantage over the one-dimensional cloud model (90.57%). The highest recognition accuracy derived from a three-dimensional SVM was 84.86%, which was lower than the cloud model (89.98%) in the same dimension. This study is expected to provide technical support for the precise recognition and forestry management on Mount Tai.

This study addresses the challenge of quantifying spatially differential vertical surface deformation (SDVSD). Traditional approaches using persistent scatterer interferometry (PSI) data often focus on bulk vertical surface deformation (VSD) but overlook directional variability and struggle with irregularly distributed persistent scatterer (PS) points, limiting comprehensive SDVSD analysis. This study proposes a regular triangle network (RTN)-based framework that tessellates the study area into uniform triangular units, enabling the systematic quantification of the SDVSD direction, magnitude and rate while mitigating spatial biases from uneven PS distributions. Applied to the Shixi area in China’s Northwest Xuzhou Coalfield, the RTN-based framework revealed that (1) the SDVSD directionality aligned with the coal strata dip and working face distribution, contrasting with VSD’s focus on the magnitude and rate alone; (2) SDVSD exhibited seasonal rate fluctuations suggesting environmental influences, and, unlike VSD, it has a non-additivity property in temporal evolution; (3) there was spatial divergence between SDVSD and VSD, i.e., high VSD rates did not necessarily correlate with high SDVSD rates, emphasizing the need for an independent spatial gradient analysis. This study demonstrates that the RTN-based framework effectively disentangles the directional and magnitude (rate) components of SDVSD, offering a robust tool for the identification of deformation hotspots and linking surface dynamics to subsurface processes. By formalizing the quantification of PSI-derived SDVSD, this study advances InSAR deformation monitoring, providing actionable insights for infrastructure risk mitigation and sustainable land management in mining regions and beyond.