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The safety injection system (RIS)is a large and complex fluid system in a nuclear power plant. Its central role is to ensure the safety of the core in the event of a breach event in the first circuit of the nuclear power plant. In order to investigate the timing of the safe injection system at the time of a Small-Break Loss-Of-Coolant Accident (SBLOCA), this paper uses the GO-FLOW method to model seven time points in the three operational phases of the safe injection system. The calculation is completed in conjunction with the failure rate of each component to give the reliability of the RIS at each point in time at SBLOCA. The final analysis yielded low reliability at the beginning of the direct cold section injection phase, which is of great reference for subsequent equipment maintenance and the safe operation of nuclear power.

As a new non-destructive testing technology, near-infrared spectroscopy has broad application prospects in agriculture, food, and other fields. In this paper, an intelligent near-infrared diffuse reflectance spectroscopy scheme (INIS) for the non-destructive testing of the sugar contents in vegetables and fruits was proposed. The cherry tomato were taken as the research object. The applicable objects and features of the three main methods of near-infrared detection were compared. According to the advantages and disadvantages of the three near infrared (NIR) detection methods, the experiment was carried out. This experiment involved the near-infrared diffuse reflection detection method, and the back propagation (BP) network model was established to research the sugar content of the cherry tomatoes. We used smoothing and a principal component analysis (PCA) to extract the final spectrum from the experimental spectrum. Taking the preprocessed spectral data as the input of the network and the measured sugar content of the cherry tomatoes as the output, the 80-12-1 network model structure was established. The cross-validation coefficient of determination was 0.8328 and the mean absolute deviation was 0.5711. The results indicate that the BP neural network can quickly and effectively detect the sugar content in cherry tomatoes. This intelligent near-infrared diffuse reflectance spectroscopy (INIS) scheme can be extended and optimized for almost all sugar-containing fruits and vegetables in the future.

Amid the COVID-19 pandemic, prevention and control measures became normalized, prompting the development of campuses from digital to intelligent, eventually evolving to become wise. Current cutting-edge technologies include big data, Internet of Things, cloud computing, and artificial intelligence drive campus innovation, but there are still problems of unintuitive scenes, lagging monitoring information, untimely processing, and high operation and maintenance costs. Based on this, this study proposes the use of digital twin technology to digitally construct the physical campus scene, fully digitally represent it, accurately map the physical campus to the virtual campus with real-time sensing, and remotely control it to achieve the reverse control of the twin virtual campus to the physical campus. The research is guided by the theoretical model proposed by the digital twin technology, using UAV tilt photography and 3D modelling to collaboratively build the virtual campus scene. At the design stage, the interactive channel of the system is developed based on Unity3D to the realize real-time monitoring, decision making and prevention of dual spatial data. A design scheme of the spiral optimization system life cycle is formed. The modules of the smart campus system were evaluated using a system usability scale based on student experience. The experimental results show that the virtual-real campus system can enhance school management and teaching, providing important implications for promoting the development and application of campus intelligent systems.

Application of micro-pattern gaseous detectors to gaseous photomultiplier tubes has been widely investigated over the past two decades. In this paper, we present a double micro-mesh gaseous structure that has been designed and fabricated for this application. Tests with X-rays and UV laser light indicate that this structure exhibits an excellent gas gain of > 7 × 1 0 4 and good energy resolution of 19% (full width at half maximum) for 5.9 keV X-rays. The gas gain can reach up to 1 0 6 for single electrons while maintaining a very low ion-backflow ratio down to 0.0005. This structure has good potential for other applications requiring a very low level of ion backflow.

In ongoing attempts to generate thermonuclear neutrons with the Z-pinch dynamic hohlraum concept at an 8-MA pulsed power facility, it has become possible to determine an upper limit for the neutron yield. The neutron time-of-flight diagnostic uses thick Pb shields and a specifically formulated fast liquid scintillator coupled to gated photomultiplier tubes to mitigate the hard bremsstrahlung x-ray (HXR) background that would otherwise overwhelm a potential neutron signal, and its suppression gives an upper-limit estimation for the neutron yield. A slow-neutron detector in the form of a BF3 counting system suggests a lower limit to the neutron yield although the early HXR pulse interference requires further confirmation as to whether the subsequent multiple pulses are induced by neutrons. Together, these measurements suggest a neutron-yield upper limit of 1.1×107.

The CSR External-target Experiment (CEE) will be the first large-scale nuclear physics experiment device at the Cooling Storage Ring (CSR) of the Heavy-Ion Research Facility in Lanzhou (HIRFL) in China. A new T0 detector has been proposed to measure the multiplicity, angular distribution and timing information of charged particles produced in heavy-ion collisions at the target region. Multi-gap resistive plate chamber (MRPC) technology was chosen as part of the construction of the T0 detector, which provides precision event collision times (T0) and collision geometry information. The prototype was tested with hadron and heavy-ion beams to study its performance. By comparing the experimental results with a Monte Carlo simulation, the time resolution of the MRPCs are found to be $\sim$ 50 ps or better. The timing performance of the T0 detector, including both detector and readout electronics, we found to fulfil the requirements of the CEE., Comment: 12 pages, 36 figures

Human identification using finger vein has been adopted in number of fields due to its high accuracy of recognition. However, image degradation caused by the strong scattering of finger tissues inevitably reduces the recognition rate. In this paper, we propose a new method to address the skin scattering problems in finger vein imaging. Firstly, a novel diffusion Point Spread Function (diffusion-PSF) model is proposed to precisely describe light scattering in finger tissues. Secondly, the blur-SURE (Stein's unbiased risk estimate) method is utilized to yield accurate estimation of the diffusion-PSF model's parameters. Finally, we adopt the multi-Wiener SURE-LET (Linear expansion thresholds) approach to improve the robustness of restoration performance. The experimental results illustrate that the proposed method significantly improves the clarity of finger vein images and enhances the venous network.

Application of micro-pattern gaseous detectors (MPGD) to photon detection has been widely investigated over the past decades. A double micro-mesh gaseous structure (DMM) prototype is developed with a thermal bonding technique for this application. Excellent performance for detecting single photon has been demonstrated in various tests with X-ray and ultra-violet (UV) laser light. The gain of the DMM prototype can reach up to >106 for single electrons while maintaining a very low ion-backflow (IBF) ratio down to

The Compressed Baryonic Matter spectrometer (CBM) is expected to be operational in the year 2024 at the Facility for Anti-proton and Ion Research (FAIR) in Darmstadt, Germany. CBM aims to study strongly interacting matter under extreme conditions. The key element providing hadron identification is the Time-Of-Flight (TOF) wall at incident energies between 2 and 10 AGeV . The TOF-wall covers the polar angular range from 2.5o–25o and full azimuth. According to the simulation results, the TOF system is required to reach a time resolution of better than 80 ps for the particle identification (PID) under high rate. The existing conceptual design foresees a 120 m2 TOF-wall composed of Multi-gap Resistive Plate Chambers (MRPC) which is subdivided into a high rate region, a middle rate region and a low rate region. The flux in the low rate region is around 1 kHz/cm2. For this region, we developed a Multistrip-MRPC using thin float glass as the resistive electrode. In this paper, we present the design of these MRPC prototypes and the results obtained during the beam test at the E3 line at Beijing Electron-Positron Collider (BEPC).

An improved self-stretching technique is introduced to construct gaseous electron multiplier (GEM) chamber with size larger than 1 meter. This new assembly method, called as ``sliding self-stretching'', gives more uniform stretching force and better performance compared to its original version.

A new T0/Trigger detector based on multi-gap resistive plate chamber (MRPC) technology has been constructed and tested for the external target experiment (ETE) at HIRFL-CSR. It measures the multiplicity and timing information of particles produced in heavy-ion collisions at the target region, providing necessary event collision time (T0) and collision centrality with high precision. Monte-Carlo simulation shows a time resolution of several tens of picosecond can be achieved at central collisions. The experimental tests have been performed for this prototype detector at the CSR-ETE. The preliminary results are shown to demonstrate the performance of the T0/Trigger detector.

A Gas Electron Multiplier (GEM) detector with an effective area of 300 mm×300 mm has been constructed using a novel self-stretching technique, which allows a highly flexible and efficient GEM detector assembly free of glue or spacers. This makes the re-opening and repair of the GEM detectors possible and significantly reduces the scrap rate in the mass production of large-area GEM detectors. With the technique, the assembly time can be limited to a few hours, a factor of ten improvement compared to that using gluing techniques. The details of design and assembly procedure of the 300 mm×300 mm GEM detector are described in this paper. This detector was tested with 8 keV X-rays for the effective gain, energy resolution and performance uniformity. The results show that the typical energy resolution is 20% at an effective gain of about 104, with fairly good uniformity.