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Introduction: The Medium Energy X-ray telescope (ME) is a collimated X-ray telescope onboard the Insight hard X-ray modulation telescope (Insight-HXMT) satellite. It has 1728 Si-PIN pixels readout using 54 low noise application-specific integrated circuits (ASICs). ME covers the energy range of 5-30 keV and has a total detection area of 952 cm2. The typical energy resolution of ME at the beginning of the mission is 3 keV at 17.8 keV (Full Width at Half Maximum, FWHM) and the time resolution is 255 us. In this study, we present the in-orbit performance of ME in its first 5 years of operation. Methods: The performance of ME was monitored using onboard radioactive sources and astronomical X-ray objects. ME carries six 241Am radioactive sources for onboard calibration, which can continuously illuminate the calibration pixels. The long-term performance evolution of ME can be quantified using the properties of the accumulated spectra of the calibration pixels. In addition, observations of the Crab Nebula and the pulsar were used to check the long-term evolution of the detection efficiency as a function of energy. Conclusion: After 5 years of operation, 742 cm2 of the Si-PIN pixels were still working normally. The peak positions of 241Am emission lines gradually shifted to the high energy region, implying a slow increase in ME gain of 1.43%. A comparison of the ME spectra of the Crab Nebula and the pulsar shows that the E-C relations and the redistribution matrix file are still acceptable for most data analysis works, and there is no detectable variation in the detection efficiency.

Purpose: The Low-Energy X-ray telescope (LE) is a main instrument of the Insight-HXMT mission and consists of 96 Swept Charge Devices (SCD) covering the 1-10 keV energy band. The energy gain and resolution are continuously calibrated by analysing Cassiopeia A (Cas A) and blank sky data, while the effective areas are also calibrated with the observations of the Crab Nebula. In this paper, we present the evolution of the in-orbit performances of LE in the first 5 years since launch. Methods: The Insight-HXMT Data Analysis Software package (HXMTDAS) is utilized to extract the spectra of Cas A, blank sky, and Crab Nebula using different Good Time Interval (GTI) selections. We fit a model with a power-law continuum and several Gaussian lines to different ranges of Cas A and blank sky spectra to get peak energies of their lines through xspec. After updating the energy gain calibration in CALibration DataBase (CALDB), we rerun the Cas A data to obtain the energy resolution. An empirical function is used to modify the simulated effective areas so that the background-subtracted spectrum of the Crab Nebula can best match the standard model of the Crab Nebula. Results: The energy gain, resolution, and effective areas are calibrated every month. The corresponding calibration results are duly updated in CALDB, which can be downloaded and used for the analysis of Insight-HXMT data. Simultaneous observations with NuSTAR and NICER can also be used to verify our derived results. Conclusion: LE is a well calibrated X-ray telescope working in 1-10 keV band. The uncertainty of LE gain is less than 20 eV in 2-9 keV band and the uncertainty of LE resolution is less than 15eV. The systematic errors of LE, compared to the model of the Crab Nebula, are lower than 1.5% in 1-10 keV., 20 pages, 10 figures, submitted

Purpose Few studies have focused on the impact of conjugal control and non-conjugal control on the innovation capability of family firms. In the context of the relative lack of research on the relationship between family firm heterogeneity and innovation ability, this study aims to focus on the differentiated impact of husband–wife-controlled family listed companies and non-husband–wife-controlled family listed companies on their innovation capabilities, which provides empirical evidence with more Chinese institutional and cultural characteristics for the development of corporate organizational management and innovation theories. Design/methodology/approach Taking all A-share listed family firms from 2007 to 2016 as the research sample, this paper examines the influence of spousal control on firm innovation level by empirical research method. Findings The empirical results show that compared with non-spousal-controlled family enterprises, spousal-controlled family enterprises have significant positive effects on the level of enterprise innovation. Further studies suggest that joint management of spousal-controlled family enterprises improves the level of innovation. Authority difference of the couple will weaken the innovation capacity. However, the wife’s professional skills can promote the innovation level. Originality/value Focusing on the characteristics of family internal structure and embedding marriage relationship in the enterprise organization, this paper investigates the influence of different characteristics of husband and wife and cooperation mode on enterprise innovation, and the conclusion enriches the theory of family business and family science, as well as provides important information reference for the stakeholder groups in the capital market.

Purpose: To assess the anti-neovascularization effect of a novel peptide NT/K-CRS derived from the kringle domain of neurotrypsin in vitro and in vivo. Methods: Primary human umbilical vein endothe...

Anomaly detection in fundus images remains challenging due to the fact that fundus images often contain diverse types of lesions with various properties in locations, sizes, shapes, and colors. Current methods achieve anomaly detection mainly through reconstructing or separating the fundus image background from a fundus image under the guidance of a set of normal fundus images. The reconstruction methods, however, ignore the constraint from lesions. The separation methods primarily model the diverse lesions with pixel-based independent and identical distributed (i.i.d.) properties, neglecting the individualized variations of different types of lesions and their structural properties. And hence, these methods may have difficulty to well distinguish lesions from fundus image backgrounds especially with the normal personalized variations (NPV). To address these challenges, we propose a patch-based non-i.i.d. mixture of Gaussian (MoG) to model diverse lesions for adapting to their statistical distribution variations in different fundus images and their patch-like structural properties. Further, we particularly introduce the weighted Schatten p-norm as the metric of low-rank decomposition for enhancing the accuracy of the learned fundus image backgrounds and reducing false-positives caused by NPV. With the individualized modeling of the diverse lesions and the background learning, fundus image backgrounds and NPV are finely learned and subsequently distinguished from diverse lesions, to ultimately improve the anomaly detection. The proposed method is evaluated on two real-world databases and one artificial database, outperforming the state-of-the-art methods.

HERMES (High Energy Rapid Modular Ensemble of Satellites) is a space-borne mission based on a constellation of nano-satellites flying in a low-Earth orbit (LEO). The six 3U CubeSat buses host new miniaturized instruments hosting a hybrid Silicon Drift Detector/GAGG:Ce scintillator photodetector system sensitive to X-rays and gamma-rays. HERMES will probe the temporal emission of bright high-energy transients such as Gamma-Ray Bursts (GRBs), ensuring a fast transient localization (with arcmin-level accuracy) in a field of view of several steradians exploiting the triangulation technique. With a foreseen launch date in late 2023, HERMES transient monitoring represents a keystone capability to complement the next generation of gravitational wave experiments. Moreover, the HERMES constellation will operate in conjunction with the Space Industry Responsive Intelligent Thermal (SpIRIT) 6U CubeSat, to be launched in early 2023. SpIRIT is an Australian-Italian mission for high-energy astrophysics that will carry in a Sun-synchronous orbit (SSO) an actively cooled HERMES detector system payload. On behalf of the HERMES collaboration, in this paper we will illustrate the HERMES and SpIRIT payload design, integration and tests, highlighting the technical solutions adopted to allow a wide-energy-band and sensitive X-ray and gamma-ray detector to be accommodated in a 1U Cubesat volume., arXiv admin note: substantial text overlap with arXiv:2101.03032

Copyright 2022 Society of Photo‑Optical Instrumentation Engineers (SPIE). One print or electronic copy may be made for personal use only. Systematic reproduction and distribution, duplication of any material in this publication for a fee or for commercial purposes, and modification of the contents of the publication are prohibited. The LAD (Large Area Detector) instrument, onboard the Sino-European mission eXTP (enhanced X-ray Timing and Polarimetry), will perform single-photon, high-resolution timing and energy measurements, in the energy range 2–30 keV, with a large collecting area. Its silicon drift detectors need shielding from NIR/Vis/UV light by astrophysical sources and the bright Earth, to avoid performance degradation. Filters made of an Al coated thin polyimide (PI) membrane will guarantee the needed out-of-band rejection while offering high X-ray transparency. They will be placed between the detectors and the capillary plate plate collimators, open to the external environment. The mission is now in phase B2 and a baseline design for the filters was produced. We describe the filter design and modeling activity, and report the characterization performed so far on X-ray transmission, pinhole and defects, thermo-vacuum cycling endurance, and bright Earth optical load shielding properties.

The 100-m X-ray Test Facility of the Institute of High Energy Physics (IHEP) was initially proposed in 2012 for the test and calibration of the X-ray detectors of the Hard X-ray Modulation Telescope (HXMT) with the capability to support future X-ray missions. The large instrument chamber connected with a long vacuum tube can accommodate the X-ray mirror, focal plane detector and other instruments. The X-ray sources are installed at the other end of the vacuum tube with a distance of 105 m, which can provide an almost parallel X-ray beam covering 0.2∼60 keV energy band. The X-ray mirror modules of the Einstein Probe (EP) and the enhanced X-ray Timing and Polarimetry mission (eXTP) and pay-load of the Gravitational wave high-energy Electromagnetic Counterpart All-sky Monitor (GECAM) have been tested and calibrated with this facility. It has been also used to characterize the focal plane camera and aluminum filter used on the Einstein Probe. In this paper, we will introduce the overall configuration and capability of the facility, and give a brief introduction of some calibration results performed with this facility.

Purpose: To assess the anti-neovascularization effect of a novel peptide NT/K-CFY derived from the kringle domain of neurotrypsin.Materials and Methods: Cell migration, lumen formation and cell proliferation assays were performed to determine the anti-neovascularization effect of NT/K-CFY in primary human umbilical vein endothelial cells (HUVECs). Chick chorioallantoic membrane (CAM) and oxygen-induced retinopathy (OIR) models were established to assess the anti-angiogenic role of NT/K-CFY in vivo. The retinal expression of vascular endothelial growth factor (VEGF) and pigment epithelium-derived factor (PEDF) was examined by western blot and real-time PCR in OIR model.Results: The in vitro results showed that NT/K-CFY effectively and safely decreased VEGF-induced cell migration, cell proliferation and tube formation in HUVECs. In addition, NT/K-CFY showed certain efficacy in angiogenesis inhibition in chicken embryos and oxygen-treated mouse pups. Moreover, the CFY peptide also improved retinal blood perfusion and reversed the abnormal expression of VEGF and PEDF in OIR mouse model.Conclusion: NT/K-CFY peptide strongly inhibits neovascularization in vitro and vivo. This novel peptide may become a promising therapeutic agent for ocular angiogenesis-related diseases.

Charged particles in the space environment can degrade the scientific performances of X-ray detectors in astronomical telescopes. An efficient countermeasure is to place a magnetic diverter at the exit pupil of optics to deflect charged particles away from the sensitive detection area. In this work, we have performed a preliminary design of the magnetic diverter on-board the enhanced X-ray Timing and Polarimetry (eXTP) observatory. It relies on a Monte Carlo method via the GEANT4 toolkit to simulate the mirror responses to charged particles, using the single scattering physics for electrons and the elastic Remizovich physics for protons. It also implements a numerical method to calculate magnetic fields generated by an assembly of permanent magnets and its impact on the trajectories of charged particles. The compact calculation scheme provides efficient access to the background level estimation given the certain radiation environment, which enables the verification of the diverter configuration with the scientific requirements.

The Einstein Probe (EP) focusing mirrors is a main load to focus and image x-rays. A single-layer which adopts Nickel substrates and Gold reflective coatings has been used for the EP focusing mirrors and has excellent performance below 8 keV. It is a possibility to enhance the effective area of higher x-ray regions by using the multilayer design. The multilayer with single block is designed and has excellent reflectance at specific x-ray energies above 8 keV. 54 multilayers are used for all mirror shells with different incident angles. The optimized B/Ir supermirror design for focusing mirrors with short focal length shows an effective area of up to 152 cm2 in 9 keV. And, the method can be used to design supermirror for higher x-ray regions, which will achieve hard x-ray detection with short focal length focusing mirrors and small hard x-ray detection satellite.

A black hole X-ray binary produces hard X-ray radiation from its corona and disk when the accreting matter heats up. During an outburst, the disk and corona co-evolves with each other. However, such an evolution is still unclear in both its geometry and dynamics. Here we report the unusual decrease of the reflection fraction in MAXI J1820+070, which is the ratio of the coronal intensity illuminating the disk to the coronal intensity reaching the observer, as the corona is observed to contrast during the decay phase. We postulate a jet-like corona model, in which the corona can be understood as a standing shock where the material flowing through. In this dynamical scenario, the decrease of the reflection fraction is a signature of the corona's bulk velocity. Our findings suggest that as the corona is observed to get closer to the black hole, the coronal material might be outflowing faster., 11 pages, 5 figures; published in Nature Communications; An artist's impression of Figure 5 is updated here, and the animation is available at http://youbei.work/research/

Computational fluid dynamics (CFD) is a powerful tool for prediction and analysis of complex multiphase flow hydrodynamics and residence time distribution (RTD) in chemical reactors. This study presented the validation and application of a filtered drag model for solid RTD prediction in a pilot-scale fluid catalytic cracking (FCC) circulating fluidized bed (CFB) riser with Geldart A particles. First, the filtered drag model implemented in the open-source MFiX-TFM solver was validated for flow hydrodynamics simulation in a FCC CFB riser. After that, the model was further employed to validate its ability for solid RTD prediction in the same riser by comparing the simulation results with the experimental data. The simulation with the filtered drag model well reproduced the tracer response experiment which is more accurate than that with the Gidaspow drag model. Simulations with both pulse and step tracer injection methods were compared, which reveals the limitation of solid RTD measurement using a pulse tracer injection method in the experiment.

The cigarette detection data contains a large amount of true sample data and a small amount of false sample data. The false sample data is regarded as abnormal data, and anomaly detection is performed to realize the identification of real and fake cigarettes. Binary particle swarm optimization algorithm is used to improve the isolation forest construction process, and isolation trees with high precision and large differences are selected, which improves the accuracy and efficiency of the algorithm. The distance between the obtained anomaly score and the clustering center of the k-means algorithm is used as the threshold for anomaly judgment. The experimental results show that the accuracy of the BPSO-iForest algorithm is improved compared with the standard iForest algorithm. The experimental results of multiple brand samples also show that the method in this paper can accurately use the detection data for authenticity identification.

The segregation of equal volumes of 2-mm and 4-mm particles inside a 14-cm-diameter spherical tumbler is numerically investigated using the Discrete Element Method (DEM). Two types of segregation take place. Initially, radial segregation appears, and then axial segregation occurs. The radial segregation occurs quickly due to percolation, with large particles moving towards the outer layer and forming a shell, while smaller particles remaining in the center and forming a core. Axial segregation is a slow process in which particles segregate into two different patterns and both with three bands. Smaller particles are at the equator and larger particles at two poles (Large–Small–Large, LSL), or vice versa (Small–Large–Small, SLS), depending upon the particles filling level inside the tumbler and/or the rotation speed of the tumbler. The total tangential force between the tumbler wall and the granular particles decreases rapidly as radial segregation occurs and then becomes almost constant as axial segregation occurs. The circulation frequency of the particles is analyzed, and the results show that the average circulation frequency of the smaller particles along the rotation axis is higher than the circulation frequency of the larger particles. Also, the distribution of the average circulation frequency is uneven. The simulations match up well with existing experimental and simulation results. The results are of common interest in applications like process engineering, where polydispersed granular materials are ubiquitous, and drums and tumblers are universally applied.

Background: Radiotherapy has been crucial in the treatment of prostate cancer. However, manual segmentation is labor intensive and highly variable among radiation oncologists, especially for lymph node volumes. Hence, in this study, a deep learning based automated contouring model is constructed with style adaptation algorithm for clinical target volumes (CTVs) of intact and postoperative prostate cancer. Methods: Computed tomography (CT) data sets for 197 prostate cancer patients, treated by one senior physician with more than 15 years of radiation work experience, during the period of November 2012 to January 2020 were selected, retrospectively. Of these patients, 167 cases were used for the training set and 30 for the test set. Two auto-delineation models were built for radical radiotherapy and postoperative radiotherapy of prostate cancer, including CTV1 for pelvic lymph nodes and CTV2 for prostate tumors or prostate tumor beds. In addition, delineation quality and processing time of the artificial intelligence (AI) algorithm were compared with those of a junior oncologist with 3 years of working experience. To further explore the number of patients required for the style adaptation model, to achieve another senior oncologist’s counting style, cases of the style transfer mode were gradually increased, adding ten patients to the training model each time. Results: No significant differences were found for the volumetric dice (VD) coefficients of the two models, CTV1 and CTV2, among DeeplabV3+, Unet++, and 3D U-net (p > 0.05). In the radical radiotherapy model, the VD coefficient of CTV1 calculated by AI, was higher than that of the one delineated by the junior physician (0.85 vs. 0.82, p = 0.018), while the VD coefficients of CTV2 counted by the junior physician and AI were the same (0.84 vs. 0.84, p = 0.958); In the postoperative radiotherapy model, the quantitative parameter of CTV1 and CTV2, counted by AI, was better than that of the junior physician (VD, 0.86 vs 0.83 for CTV1, p = 0.041; 0.79 vs 0.73 for CTV2, p = 0.003, respectively). The median delineation time for AI was 0.23 min in the postoperative model and 0.26 min in the radical model, which were significantly shorter than those of the physician (50.40 min and 45.43 min, respectively, p < 0.001). The correction time of the senior physician for AI was much shorter compared with that of the junior physician in both models (p < 0.001). For style adaptation from one physician to another, approximately 20 cases were required to construct a personal style based on the basic delineation model. Conclusion: Using deep active learning and attention mechanism, a highly consistent and time-saving contouring model was built for CTVs of prostate cancer. It was possible to train the style adaptation mode from one physician’s style to that of another with limited patient samples.

Recently, the system parameters of Cygnus X-1, i.e., the black hole mass M, the orbital inclination i and the source distance D, have been updated. As the input constraints of the continuum-fitting method, it is necessary to refine the spin with these new parameters. The Hard X-ray Modulation Telescope (HXMT, also named Insight) was successfully launched on June 15th, 2017 in China. In this work, we analyzed spectra obtained by the Insight-HXMT during 2017-2018 and re-estimated the spin via the continuum-fitting method. We first re-estimated the spin using old parameters and found the dimensionless spin parameter to be a ⁎ > 0.934 (3σ), which is consistent with previous measurements both from the continuum-fitting and iron-line fitting methods ( Gou et al. 2011 , Gou et al. 2014 ; Fabian et al. 2012 , Walton et al. 2016 , Tomsick et al. 2018 ). Then, when the new parameters were applied, we obtained an increased spin: a ⁎ > 0.967 (3σ), which is also consistent with the recent measurement (Zhao et al. 2020, submitted to ApJ) and also confirms an extreme Kerr black hole lying in this system.

The CsI detectors of the High Energy X-ray Telescope of the Hard X-ray Modulation Telescope (HXMT/CsI) can be used for gamma-ray all sky monitoring and searching for the electromagnetic counterpart of gravitational wave source. The instrumental responses are mainly obtained by Monte Carlo simulation with the Geant4 tool and the mass model of both the satellite and all the payloads, which is updated and tested with the Crab pulse emission in various incident directions. Both the Energy-Channel relationship and the energy resolution are calibrated in two working modes (Normal-Gain mode & Low-Gain Mode) with the different detection energy ranges. The simulative spectral analyses show that HXMT/CsI can constrain the spectral parameters much better in the high energy band than that in the low energy band. The joint spectral analyses are performed to ten bright GRBs observed simultaneously with HXMT/CsI and other instruments (Fermi/GBM, Swift/BAT, Konus-Wind), and the results show that the GRB flux given by HXMT/CsI is systematically higher by 7.0 ± 8.8 % than those given by the other instruments. The HXMT/CsI-Fermi/GBM joint fittings also show that the high energy spectral parameter can be constrained much better as the HXMT/CsI data are used in the joint fittings.

Deadtime is the time period during which a detector processes the previous photon event and any later events will be ignored, thus the calculation of deadtime is of great importance to reconstruct the incident photon flux from the recorded counts. The High Energy X-ray telescope (HE) on-board the Insight-HXMT satellite records the deadtime only for a fixed time bin (i.e. 1 s), therefore it is impossible to directly obtain the deadtime for an arbitrary time interval, especially for high-energy transients much shorter than one second. Based on the electronics model of HE, we establish a deadtime calculation method to derive the deadtime in any time interval. We apply this method to transient sources observed by HE, including Gamma-ray Bursts (GRB) and Terrestrial Gamma-ray Flashes (TGF). Furthermore, since the data processing capacity of HE electronics is limited, HE suffers data saturation for very bright GRBs. During the saturation period, a significant part of counts signal cannot be recorded. We find that the amount of lost counts can be estimated by comparing the recorded 1 s deadtime and the calculated deadtime using the method mentioned above.

Three high energy particle monitors (HPMs) employed onboard the Hard X-ray Modulation Telescope Insight-HXMT) can detect the charged particles from South Atlantic Anomaly (SAA) and hence provide the alert trigger for switch-on/off of the main detectors. Here a typical design of HPM with high stability and reliability is adopted by taking a plastic scintillator coupled with a small photomultiplier tube (PMT). The window threshold of HPM is designed as 1 MeV and 20 MeV for the incident electron and proton, respectively. Before the launch of Insight-HXMT, we performed in details the ground calibration of HPM. The measured energy response and its dependence on temperature are taken as essential input of Geant4 simulation for estimating the HPM count rate given with an incident particle energy spectrum. This serves as a guidance for choosing a reasonable working range of the PMT high voltage once the real SAA count rate is measured by HPM in orbit. So far the three HPMs have been working in orbit for more than two years. Apart from providing reliable alert trigger, the HPMs data are used as well to map the SAA region., Comment: 7 pages,15 figures

We present a detailed timing study of the brightest persistent X-ray source Sco X-1 using the data collected by the Hard X-ray Modulation Telescope ( I n s i g h t -HXMT) from July 2017 to August 2018. A complete Z-track hardness-intensity diagram (HID) is obtained. The normal branch oscillations (NBOs) at ∼ 6 Hz in the lower part of the normal branch (NB) and the flare branch oscillations (FBOs) at ∼ 16 Hz in the beginning part of the flaring branch (FB) are found in observations with the Low Energy X-ray Telescope (LE) and the Medium Energy X-ray Telescope (ME) of I n s i g h t -HXMT, while the horizontal branch oscillations (HBOs) at ∼ 40 Hz and the kilohertz quasi-periodic oscillations (kHz QPOs) at ∼ 800 Hz are found simultaneously above 20 keV for the first time on the horizontal branch (HB) by the High Energy X-ray Telescope (HE) and ME. We find that for all types of the observed QPOs, the centroid frequencies are independent of energy, while the root mean square (rms) increases with energy; the centroid frequencies of both the HBOs and kHz QPOs increase along the Z-track from the top to the bottom of the HB; and the NBOs show soft phase lags increasing with energy. A continuous QPO transition from the FB to NB in ∼ 200 s are also detected. Our results indicate that the non-thermal emission is the origin of all types of QPOs, the innermost region of the accretion disk is non-thermal in nature, and the corona is nonhomogeneous geometrically.

The Large Area Detector (LAD) is the high-throughput, spectral-timing instrument onboard the eXTP mission, a flagship mission of the Chinese Academy of Sciences and the China National Space Administration, with a large European participation coordinated by Italy and Spain. The eXTP mission is currently performing its phase B study, with a target launch at the end-2027. The eXTP scientific payload includes four instruments (SFA, PFA, LAD and WFM) offering unprecedented simultaneous wide-band X-ray timing and polarimetry sensitivity. The LAD instrument is based on the design originally proposed for the LOFT mission. It envisages a deployed 3.2 m2 effective area in the 2-30 keV energy range, achieved through the technology of the large-area Silicon Drift Detectors - offering a spectral resolution of up to 200 eV FWHM at 6 keV - and of capillary plate collimators - limiting the field of view to about 1 degree. In this paper we will provide an overview of the LAD instrument design, its current status of development and anticipated performance.

The 100-m X-ray Test Facility of the Institute of High Energy Physics (IHEP) was initially proposed in 2012 for the test and calibration of the X-ray detectors of the Hard X-ray Modulation Telescope (HXMT) with the capability to support future X-ray missions. The large instrument chamber connected with a long vacuum tube can accommodate the X-ray mirror, focal plane detector and other instruments. The X-ray sources are installed at the other end of the vacuum tube with a distance of 105 m, which can provide an almost parallel X-ray beam covering 0.2$$\sim$$ ∼ 60 keV energy band. The X-ray mirror modules of the Einstein Probe (EP) and the enhanced X-ray Timing and Polarimetry mission (eXTP) and payload of the Gravitational wave high-energy Electromagnetic Counterpart All-sky Monitor (GECAM) have been tested and calibrated with this facility. It has been also used to characterize the focal plane camera and aluminum filter used on the Einstein Probe. In this paper, we will introduce the overall configuration and capability of the facility, and give a brief introduction of some calibration results performed with this facility.