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Software Platform for European XFEL: Towards Online Experimental Data Analysis
摘要： Large amount of data being generated at large scale facilities like European X-ray Free-Electron Laser (XFEL) requires new approaches for data processing and analysis. One of the most computationally challenging experiments at an XFEL is single-particle structure determination. In this paper we propose a new design for an integrated software platform which combines well-established techniques for XFEL data analysis with High Performance Data Analysis (HPDA) methods. In our software platform we use streaming data analysis algorithms with high performance computing solutions. This approach should allow analysis of the experimental dataflow in quasi-online regime.
关键词： single particle imaging,X-ray Free-Electron Laser,High Performance Data Analysis,X-ray Cross-Correlation Analysis,Expectation-Maximization
更新于2025-09-23 15:22:29
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Modeling of Short-Range Ultraviolet Communication Channel Based on Spherical Coordinate System
摘要： The study on short-range ultraviolet (UV) communication (UVC) channel modeling is often based on prolate-spheroidal coordinate system in previous studies. In this letter, we propose a single scattering coplanar model based on spherical coordinate system, where the transmitter beam and receiver field of view (FOV) can point arbitrarily under the limitation that the sum of transceiver elevation angles and half of their own FOV is less than 180°, and the transmitter beam and receiver FOV are above ground. We utilize the number of intersections between a special ray on the transmitter cone and the receiver conical surface to distinguish the UVC scenarios, which makes the analysis of UVC channel modeling comprehensible. Meanwhile, we validate the proposed model in comparison with the single scattering model and the Monte Carlo simulation model through numerical calculations. The results show that the proposed model agrees well with the both models. This work presents a new method to estimate the path loss of short-range UVC and provides guidelines for the experimental system design.
关键词： ultraviolet communications,Atmospheric propagation,free-space optical communication
更新于2025-09-23 15:22:29
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-Distribution Dual-Hop RF/FSO Systems
摘要： In this correspondence, we investigate the physical-layer security of a mixed radio frequency/free space optical (RF/FSO) dual-hop communication system for both fixed- and variable-gain relaying schemes. More specifically, we only assume that the eavesdropping happens at the RF link because the optical link has high security. We assume that all RF channels suffer from η–μ fading, while the FSO link experiences M-distributed fading. Then, we derive some analytical results for the average secrecy rate and the secrecy outage probability.
关键词： secrecy outage probability,Average secrecy rate,radio frequency-free space optical,M-distributed fading,η-μ fading,physical-layer security
更新于2025-09-23 15:22:29
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Angular and Spectral Bandwidth of Extreme UV Multilayers Near Spacer Material Absorption Edges
摘要： High resolution imaging systems for EUV range are based on multilayer optics. Current generation of EUV lithography uses broadband Sn LPP sources, which requires broadband mirrors to fully utilize the source power. On the other hand, there always remains a possibility to use FEL or synchrotron as EUV source. FEL can produce very bright narrowband EUV light of a tunable wavelength, and the spectral bandwidth of the mirror is no longer a restriction. In this paper we look at the consequences of switching to different wavelengths if FEL source is used. For instance, it is known that the reflectance of Mo/Si multilayers increases when approaching Si L-edge, and the spectral bandwidth drops. But the behavior of an angular bandwidth (and its relation with the spectral bandwidth) is usually left out. It is also sometimes assumed that these bandwidths are correlated. For a large aperture EUV optical system with diffraction-limited resolution angular acceptance of a mirror is also a very important parameter. We show that the angular bandwidth of several multilayer systems (Mo/Si, Mo/Be, Ru/Si, Ru/B, La/B) actually increases close to spacer absorption edges, opposite to what occurs with the spectral bandwidth. We study this effect and show that it is caused by an interplay of changing optical constants of respective materials used in these multilayer combinations. We also provide an experimental check of the angular bandwidth of Mo/Si multilayers at 13.5 and 12.6 nm, which confirms our calculations.
关键词： Multilayer,Free Electron Laser,EUV Photolithography
更新于2025-09-23 15:22:29
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Loophole-Free Bell Tests and the Falsification of Local Realism
摘要： Quantum mechanics is strictly incompatible with local realism. It has been shown by Bell and others that it is possible, in principle, to experimentally differentiate between local realism and quantum mechanics. Numerous experiments have attempted to falsify local realism; however, they have consistently failed to close the detection loophole under strict locality conditions, thereby allowing local realistic explanations for their observations. In 2015, three experiments took place that tested local realism without the impediments of these significant loopholes. Between these three experiments, a substantial data set was collected. All of the collected data show a strong violation of local realism and strong support for quantum mechanics. This article reviews the theoretical basis of Bell tests and the affiliated loopholes, as well as the methods employed by these recent experiments and the implications of the results they observed.
关键词： Local Realism,CHSH Inequality,Loophole-Free Bell Test,CH Inequality,Quantum Mechanics
更新于2025-09-23 15:22:29
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Diagnostic performance of free-breathing coronary computed tomography angiography without heart rate control using 16-cm z-coverage CT with motion-correction algorithm
摘要： Objectives: To evaluate the feasibility of coronary computed tomography angiography (CCTA) in patients with free-breathing using 16-cm z-coverage CT with motion correction algorithm. Methods: 616 patients underwent CCTA without heart rate control. 325 examinations were performed during breath-holding (group A), and the remaining 291 were performed during free-breathing (group B). The image quality scores were defined as 1 (excellent), 2 (good), 3 (adequate), and 4 (poor). 22 patients in group A and 24 in group B underwent invasive coronary angiography (ICA) after CCTA within two weeks. The image quality score, diagnostic accuracy using ICA as reference, signal-to-noise ratio (SNR), and effective dose (ED) were compared between the two groups. Results: Mean heart rate during scanning was 70.8±13.8bpm in group A and 70.7±13.2bpm in group B (P=0.950). No significant differences were observed in SNR and image quality score (1.49±0.62 vs. 1.53±0.67; P=0.647) between the breath-holding and free-breathing groups. ED (1.99±0.83mSv vs. 2.01±0.88mSv) was not significantly different between the two groups (P=.975). In a segment-based analysis, the sensitivity, specificity and diagnostic accuracy in the detection of coronary stenosis of more than 50% were 82.1%, 96.8% and 92.2%, respectively in the breath-holding group and 82.2%, 96.6% and 92.2%, respectively in the free-breathing group with no significant differences for these parameters between the two groups. Conclusions: CCTA for patients without heart rate control and during free-breathing using 16-cm z-coverage CT with motion correction algorithm showed no significant difference in image quality and diagnostic performance compared with CCTA during breath-holding.
关键词： X-ray computed,Free breathing,Breath holding,Coronary vessel,Tomography
更新于2025-09-23 15:22:29
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Ni doped noble-metal-free CdZnNiS photocatalyst for high-efficient photocatalytic hydrogen evolution reduction by visible light driving
摘要： In this paper, we report a method that the transition element nickel is doped into the interstitial position of CdZnS (CZS) nanoparticles for their photocatalytic hydrogen evolution activity boosting. It is demonstrated that CdZnNiS nanocrystalline materials (with 0.5 wt% of Ni) could achieve the highest photocatalytic H2-evolution activity of 25.4 mmol·g?1·h?1 in sulfide and sulfite solution under visible light which value is 1.16 times higher than that of Pt modified CdZnS particles (with 3 wt% of Pt). This work evidences the possibility of substitution of noble metal cocatalyst by adding a suitable inexpensive Ni to achieve high-efficient visible light driven water splitting hydrogen production.
关键词： Semiconductors,CdZnNiS nanocrystalline materials,Noble-metal-free cocatalyst,Gap doping,Nanocomposites,Water splitting
更新于2025-09-23 15:22:29
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ZnO/porous carbon composite from a mixed-ligand MOF for ultrasensitive electrochemical immunosensing of C-reactive protein
摘要： Carbon-based nano-composite materials obtained via simple thermolysis of metal-organic framework (MOF) have competitive virtues in accordance of layered porosity, controllable morphologies, and easily functionalizing with other metal/metallic oxides or hetero atoms. These make them directly as high activity catalysts or supports for various electrochemical sensor. Herein, we developed a novel ZnO/porous carbon matrix (ZnO/MPC)-based electrochemical immunosensing through thermolysis of a mixed-ligand MOF (Zn-BDC-TED) for real sample analysis of C-reactive protein. The ZnO/MPC and ionic liquid (IL) composite membrane modified electrode displayed prominent conductivity and biocompatibility for ultrasensitive detection of C-reactive protein (CRP). Subsequently, the step-by-step assembly process of the CRP immunosensor was monitored by electrochemical measurements including cyclic voltammogram (CV) and electrochemical impedance spectra (EIS). After the parameter optimization, the differential pulse voltammetry (DPV) response decreased linearly with the logarithm of CRP levels in an extensive range of 0.01–1000 ng·mL?1, and the detection limit was as low as 5.0 pg·mL?1. Meanwhile, the lable-free immunosensor also showed excellent selectivity, reproducibility and stability. We believe that ZnO/MPC composite and many carbon-based nano-composite materials obtained via simple thermolysis of MOF will be a prospective platform for sensitive detecting other biomarkers.
关键词： ZnO/MPC,C-reactive protein,Electrochemical immunosensor,Pyrolysis,Lable-free
更新于2025-09-23 15:22:29
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Red-Free Light for Measurement of Intraocular Pressure Using Goldmann Applanation Tonometer without Fluorescein
摘要： Purpose: To evaluate the use of red-free light for the measurement of intraocular pressure (IOP) using a Goldmann applanation tonometer without fluorescein. Methods: This cross-sectional study was carried out on 500 eyes in 250 patients attending the Ophthalmology Outpatient Clinic at Suez Canal University Hospital. The IOP was measured using a Goldmann applanation tonometer mounted on a Haag-Streit slit-lamp. The measurements were performed first using red-free light without fluorescein. Then the measurements were repeated with cobalt blue light and topical fluorescein on the same eyes. Results: The mean IOP was 15.23 ± 3.3 (SD) mm Hg using the red-free light without fluorescein, whereas it was 15.78 ± 3.7 (SD) mm Hg when measured using cobalt blue light after the application of fluorescein to the conjunctival sac. This difference was not statistically significant. Conclusions: Measurement of IOP with a Goldmann applanation tonometer with red-free light and without the use of fluorescein is simple, saves time, and gives an accurate IOP measurement relative to the traditional measurement technique with cobalt blue light and topical fluorescein.
关键词： Red-free light,Intraocular pressure,Goldmann applanation tonometer
更新于2025-09-23 15:22:29
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Novel Porous Boron Nitride Nanosheet with Carbon Doping: Potential Metal-Free Photocatalyst for Visible-Light-Driven Overall Water Splitting
摘要： The band gap of hexagonal boron nitride (h-BN) is far too wide for efficiently utilizing visible light, limiting its application in photocatalysis. The present study employs first principles calculations to demonstrate that the band gap energies of porous h-BN (p-BN) can be tuned by carbon doping to levels appropriate for the absorption of visible-light, and that the conduction band and valence band match well with the potentials of both hydrogen and oxygen evolution reactions. Importantly, a strategy of carbon doping to improve the energy level of valence band maximum is also proposed. Moreover, the carbon-doped p-BN exhibits good separation between photogenerated electrons/holes and structural stability at high temperatures. The DFT results help the design of high-performance two-dimensional photocatalysts that avoid the use of metals.
关键词： metal-free catalysts,photocatalyst,porous boron nitride nanosheets,overall water splitting,band structure engineering
更新于2025-09-23 15:22:29