The rapid penetration of generative artificial intelligence (Generative AI) in higher education has sparked widespread debate over whether it is an empowering tool or a substitute for thinking. This study collected 785 original posts from the Zhihu platform, cleaned and retained 740 valid samples, and used SnowNLP sentiment analysis and LDA topic modeling to depict the perception of college students regarding the use of AI to complete coursework. The results show a significant differentiation and polarization in emotional attitudes: 84.7% of the posts held a positive attitude $(\mathrm{N}=627)$, 12.2% held a negative attitude $(\mathrm{N} = 90)$, and only 3.1% were neutral $(\mathrm{N}=23)$. The LDA topic model further revealed five core discourses, ranging from “assistance in essay writing” to “avoidance of academic detection”. Word cloud and TF-IDF keyword analysis indicated that positive discourses focused on “ideas”, “frameworks”, and “efficiency”, while negative discourses were strongly associated with “dependence”, “laziness”, and “plagiarism reduction”. The core finding of this study is that students' perception contradictions are essentially the result of differentiated AI usage patterns - when AI is used for knowledge construction, it is regarded as a “catalyst for thinking”, but when it is used for content substitution and subsequently leads to deceptive behaviors, it becomes an “academic crutch”. This finding provides new evidence for the development of cognitive load theory in the AI era and offers direct empirical support for universities to formulate AI usage guidelines for different scenarios.

Promoting the development of deep-sea mineral exploration instrumentation can help alleviate the global resource shortage faced by mankind. X-ray fluorescence (XRF) spectrometry has been widely used in the in situ analysis of deep-sea minerals owing to its fast analytical speed, nondestructive nature, and wide analytical range. This study focused on the structural safety and detection efficiency of X-ray fluorescence in situ measurement equipment under high pressure for deep-sea XRF analysis. This study first combined finite element analysis and experiments to design and optimize the structure of an X-ray probe tube required for deep-sea mineral exploration and to determine the Be window thickness to ensure stress safety. Subsequently, the Monte Carlo method was used to analyze and optimize the Be window thickness on the X-ray probe tube to improve the accuracy of the elemental analyses. Finally, the effect of seawater thickness between the transmitter outer tube and rock wall was also considered. The results show that based on ocean depth in different detection environments, Be windows with a thickness of 1.5 mm or 2.0 mm can be selected to improve the detection efficiency of the device while ensuring the structural safety of the instrument. According to the design features and detection requirements of the device, in deep-sea exploration of minerals with characteristic peak energies below 10 keV, the transmitter outer tube should be as close as possible to the rock wall inside the logging. When the characteristic peak energy of the minerals is more than 10 keV, the distance between the transmitter outer tube and rock wall inside the logging should be controlled to approximately 2 mm. This study provides feasible solutions for future deep-sea mineral resource development and a useful reference for elemental analysis of minerals in the deep-sea or other extreme working environments.

在核辐射探测中针对输出微电流的探测器，普遍采用美国ADI公司设计生产的ADA4530芯片搭建跨阻放大电路来进行微电流信号的测量。目前国内暂无ADA4530的国产替代，为解决该芯片的卡脖子问题，基于分离的场效应管和常规运算放大芯片搭建I-V跨阻转换电路，实现纯国产器件的弱电流放大电路设计。该电路的输出电压范围在0到10V之间，经过测试，当反馈电阻为100GΩ，输入电流为0.1~100pA时，其线性拟合优度为0.99998，相对偏差为0.235%，噪声峰峰值为0.057pA。当反馈电阻为10GΩ，输入电流为1pA时，在-10℃~80℃的温度变化范围内，其温漂小于0.042pA/℃。当反馈电阻为10GΩ，输入端悬空时，在室温6小时的稳定性测试中，输出漂移小于0.2662pA。

As China strives to build world-class universities, discipline competitions have been employed to foster innovative talents and have been given attention by higher education institutions. In this study, we explored the impact of discipline competitions on the quality of undergraduate education. Using competition data and related teaching indicators collected from multiple universities in China, the following hypothesis was tested: "The development of discipline competitions significantly improves students' continuous learning capabilities". Linear regression and support vector regression (SVR) models were employed to test the hypothesis. The results showed that the competitions play a vital role in developing students' capabilities and practical skills, although their influence on students' postgraduate admission rates is modest. The results can be used for educational reform and policy adjustments, advocating for the integration of discipline competitions into educational strategies.

This paper proposes an innovative detector to measure the radioactivity of water based on ZnS(Ag)-coated plastic scintillating fibers. The system includes an internal cavity for measuring the total alpha and total /3 activities in the test water sample and an external cavity for excluding muons from external background radiation and reducing gamma rays in the internal water sample through anti-coincidence measurement. Geant4 simulations modeled radiation interaction, scintillation light generation, and its propagation within the detector. Simulation results are used to determine the optimal thickness of the ZnS(Ag) coating, length of the plastic scintillating fibers in the inner cavity, and thickness of the aluminum cylinder between the inner and outer cavities. When the ZnS(Ag) layer thickness is 14 mu m, fiber length is 400 mm, and 353 fibers are arranged in parallel, the minimum detection limit for alpha particles is 0.5 Bq/L within 1.65 hours of detection time, and within 4.82 hours, the detection limit for /3 particles reaches 1 Bq/L.

The fixed effects model is a widely used statistical method in panel data analysis as it eliminates the heterogeneity that cannot be observed at the individual or temporal level. The model is used to evaluate the effect of independent variables on dependent variables accurately. The model also reduces the bias caused by omitted variables by introducing individual fixed effects, temporal fixed effects, or a combination to capture individual and temporal characteristics that do not change over time or by individuals. We applied the fixed effect model to the nuclear technology course to conduct panel data analysis. We controlled the interference of individual heterogeneity and time-invariant characteristics to effectively separate the inter-individual differences (between effect) and the internal changes (within effect). By assessing the differences among influencing factors accurately, the fixed-effect model is fitted to the nonlinear laws of complex factors (especially subjective individual evaluations), which is important for the formulation of educational and teaching reform strategies.

The quadratic polynomial regression model with L2 regularization is developed by combining the nonlinear fitting ability of polynomial regression and the regularization feature of ridge regression. The model is widely used in regression in machine learning as it captures the nonlinear relationship of data by introducing quadratic terms, such as x2, and at the same time, uses L2 regularization (weight decay) to prevent overfitting and improve the generalization ability of the model. The model solves the common overfitting problem in traditional polynomial regression. We applied L2 regularization in quadratic polynomial regression to analyze the nonlinear relationship between the employment rate of graduates and factors, including entrance scores, student-teacher ratio, and library collection volume, in higher education. L2 regularization constrains the model weights by adding a penalty term to the loss function, avoiding overfitting caused by high-order polynomials. In addition, the developed model maintains an analytical solution (closed-form solution), which is appropriate for small to medium-sized datasets, with relatively good fitting performance.

Identifying the pulse shape is a crucial step in detecting the contamination of surfaces by α/β radioactive isotopes. In this study, the authors propose a self-adaptive method to identify the pulse shape by applying the Gaussian mixture model and the constant-fraction timing algorithm to a ZnS(Ag) and plastic scintillator to improve its accuracy of detection of low-energy particles, and realize automatic calibration to reduce the operational difficulty of the process and improve its stability. The proposed method comprises a feature extraction algorithm running on an FPGA as well as a classifier and a training machine running on an embedded processor. The feature extraction algorithm forms the core of the proposed method, is independent of the amplitude of the pulse signal, and can extract important information (pulse width and rise time) from the pulse signals to simplify the probabilistic model. The proposed method was tested on a ZnS(Ag) plastic scintillator, and the results showed that the feature extraction algorithm was more robust against errors in the amplitude of the pulse signal than the method that involves using a fixed threshold. The error in its results compared with those of measurements could be controlled to within 4% during mixed radiation field tests involving a single source of radiation. Moreover, we have deployed a complete program to train the model on the platform to support onboard model training and self-adaptive parameter estimation without requiring human intervention.

The research of controlled nuclear fusion is not a simple process. The upcoming accomplishment of ITER means the beginning of a new phase of controlled nuclear fusion, which is building a fusion reactor. The operating electronics related to fusion reactors need to adapt to harsh environment and minimize the risk of any possible irradiation. Pre-amplifiers are widely used for signal conditioning in various diagnostic systems. And if not shielded, they would be easily damaged in a environment with strong radiation. In this study, a kind of Radiation Resistant Pre-amplifier (RRP) has been designed and manufactured. To verify its performance under radiation, tests in both gamma and neutron fields were carried out. And the performance of RRP is compared with that of an Ordinary Pre-amplifier (OP). The RRP was irradiated with gammas from a Co-60 source up to an accumulated dose of 1MGy, and was also irradiated with neutrons under a tandem accelerator up to a total neutron flux of 1013 n/cm2. The test results prove a performance improvement of radiation hardness on the RRP. And shielding optimization has been discussed with the circumstances of ITER port cell area in this paper. The RRP could better adapt to the complex irradiation environment of fusion reactors and possibly reduce shielding in the future.

Radioactive material inspection in public is important to nuclear safety, and it is also the key security for holding large-scale events, while fast and efficient means of detecting radioactive materials are an important technical guarantee for nuclear safety. In this paper, energy and time distribution characteristics information of the natural background and target nuclide gamma particles are used to improve the sequential background comparison method. By using those energy and time distribution characteristics information, with the half-life and characteristic gamma-ray energy and branching ratio information of the nuclide, the response time and the identification accuracy of extremely low radioactive nuclides detected under natural-radiation background can be improved. Based on the theoretical research, the particle event acquisition device with the LaBr3(Ce) detector was used to carry out the experimental verification, and the results show that, this method can identify 137Cs (characteristic energy of 0.662 MeV，8700 Bq，the position relative to the detector is 30 cm) in 6.2 s, and identify 60Co (characteristic energy of 1.173 MeV and 1.332 MeV, 4500 Bq, the position relative to the detector is 15 cm) in 5.9 s. Experiments prove that the improved background comparison-based sequential Bayesian method can identify low radioactivity radionuclides under natural-radiation background rapidly.

To assess hadronic and electromagnetic components from extensive air shower events (EAS), 16 6Li-based ZnS (Ag) scintillator detectors combine into a thermal neutron detector array. After a shower event, each scintillator screen can concurrently catch neutrons and electrons, producing a succession of electrical signals with different pulse shapes. These signals are sampled by 16 oscilloscope-like circuits and sent over a single serial link, where EAS-related sampling results may fill each channel's memory. However, there are presently no specific studies to address data congestion in such random signal digitizers. Here, we demonstrate that decreasing the sampling rate on the trailing edge can compress data size while preserving pulse shapes and that optimizing the read/write time of memories can enhance transmission speed between asynchronous clock domains. According to test results, the 100 MHz serial transceiver can send 1996 pulses per second when only receiving data from one channel at 50 MHz rates, and it can send 242 pulses per second when simultaneously receiving data from 32 channels (16 × 2). This method increases transmitting speeds 2.3 times over previously employed algorithms, and the compressed rate reaches 97.74%. In addition, we found that the total error rate is lower than 10–10. Our findings also show how memory controllers would probably operate in data flows of 32 channels, predicting the slower writing time and the faster reading time that can complete sending a packet of one channel in the shortest time. We anticipate that our assay can help more detector arrays that require waveform transmission.

In this study, an online detector system based on plastic scintillators is designed to monitor the activity of tritiated water in the liquid effluents of nuclear power plants. The feasibility of the detector is verified via simulation on Geant4, and the optimal detector structure size is determined. A back-end electronics system is designed, and an experimental measurement platform for β-rays based on a 40KCl solution is constructed. Thirteen 40KCl solutions with different activities ranging from 10 to 4500 Bq/L are measured, and 1300 V is determined as the optimal operating high voltage of the photomultiplier tubes. A linear fit is performed in 10-min counts, and the maximum linear goodness of fit (R2) achieved is 0.9992. Long-term stability measurements are performed for two detectors, one filled with air and the other with a 40KCl solution exhibiting an activity of 2000 Bq/L. The relative deviation of the counts of the detector system every 10 min is 0.998% when the 40KCl solution is used, and the maximum Gaussian R2 of the counts is 0.9849.

Due to possible nuclear accidents as a radioactive source loss as happened in Nanjing, China, there is demand for rapid identification of nuclides. This paper proposes a new recognition algorithm based on sequential Bayes that reduces the time required for that identification. A nuclide identification system was built by appropriate detector selection, electronic design, and software programming. Experiments show that the radioactive sources Cs-137 (with an activity of 46500 Bq) and Co-60 (with an activity of 39000 Bq) at a distance of 40 cm from the detection system can be distinguished rapidly within 3.0 and 4.1 s respectively with a detection rate reaching 100%.

A measuring circuit is designed based on the transimpedance amplifier. The methods of reducing parasitic capacitance and improving amplifier performance are introduced in detail. The influence of the parasitic capacitance generated by the feedback resistors on the bandwidth in the transimpedance amplification circuit is discussed. The circuit can measure the wide-dynamic-range low current ranging from 10 -13 A to 10 -5 A in four ranges. The circuit's bandwidth is up to 500 Hz when the circuit can normally work to measure a wide-range low current. The peak-to-peak amplitude of circuit noise is less than 0.22 pA. The current drift is less than 1.06 fA/ ∘ C over a temperature range of 0 ∘ C to 85 ∘ C, and the integral nonlinearity is less than 0.25%.

Portable gamma spectrometer is widely used in many fields, such as field prospecting, environmental radiation monitoring and scientific experiments. In order to further reduce the volume of portable energy spectrometer and improve its energy spectrum performance, so as to extend its application field. Based on the latest scintillation crystal materials, semiconductor photoelectric converters and high performance microprocessors, we have developed a new generation of portable gamma spectrometer. In terms of detector design, GAGG: Ce crystal coupled SIPM array is used to successfully design and manufacture a compact energy spectrum probe with high efficiency and high energy resolution; in terms of data acquisition circuit, high performance ARM processor and its own ADC peripheral are used to replace the traditional circuit architecture of FPGA + ADC, and a special signal processing ARM program is designed to realize online energy spectrum measurement, which greatly reduce the circuit Size and system power consumption. To sum up, based on GAGG: Ce crystal coupled SIPM and ARM processor, a pocket type energy spectrometer with low cost, small volume, low power consumption and high performance has been successfully developed. The volume of the whole spectrometer is only 80 mm × 40 mm × 40 mm, and the weight is 200 g. The tested power of the spectrometer is 481mW, and it can work for 26 hours with its own power supply. The linear goodness of fit of the spectral response is 0.996, and the energy resolution is 5.2% (@ 662 keV).

EN-detectors (Electron-Neutron Detector) can provide detection of both electrons and thermal neutrons generated in ground by secondary hadrons of extensive air shower (EAS). The 400 EN-detector array, so called ENDA (Electron-Neutron Detector Array), was proposed to add into the LHAASO (Large High Altitude Air Shower Observatory) project to improve its capability of EAS hybrid detection. ENDA will be located at the center of the first 1/4 of the KM2A surface scintillator array. Supported by Tibet University, Institute of High Energy Physics of Chinese Academy of Sciences (IHEP CAS) and Institute for Nuclear Research of Russian Academy of Science (INR RAS), 64 EN-detectors of so called ENDA-64 have been produced at Hebei Normal University and pulse shapes are sampled with FADCs made by Sichuan University, networked with the White Rabbit precise clock system. We expect to deploy ENDA-64 (64 EN-detectors) at LHAASO site in 2019. In this paper, we report the results of ENDA-16 (16 EN-detectors) testing run at Yangbajing (YBJ) together with YBJHA offering electrons and muons. It is the first time to obtain the high altitude hybrid detection results between neutrons, electrons and muons in EAS.

Currently, the liquid scintillation method is widely used to measure the activity of tritiated water in the primary circuit of nuclear power plants, which leads to the continuous production of radioactive waste during measurement. In addition, the real-time activity information of tritiated water cannot be obtained. To solve this problem, herein we present an online tritiated water measurement method based on plastic scintillators that used the optical transport process in the Geant 4 software toolkit to build a model of plastic scintillation detection for tritiated water. Through simulation, the basic geometric dimensions of the detector were determined. In this dimension, using one detector to measure for 3 h, when the tritiated water activity was 100 Bq/L, its resolution was 16% (16 Bq/L). In addition, calculations were performed for the presence of other background signals to obtain the minimum detectable concentration.

The Dynamic Range Expansion System of the Water Cherenkov Detector Array (WCDA++) is an important component of the Large High Altitude Air Shower Observatory (LHAASO). We have designed an electronic readout system for it. Using a multi-channel scheme, the electronic system can process multiple detector signals. High and low gains of the system have been included to process the output signals from the photomultiplier tube (PMT) anode and dynode, respectively, and photo-electrons, p.e., with energies ranging from 1 p.e. to 3000 p.e. have been covered. Using multistage resistor-capacitor (RC)(m) filtering circuit, the electronic resolution is better than 10%@1 p.e. and 2%@3000 p.e., while the relative deviation of integral linear is better than 5%@1 p.e. and 2%@3000 p.e. At 50 MHz clocked frequency, the measurement accuracy of the electronic jitter is better than 20 ns. The system uses four pairs of differential lines with a 50 Mbps transmission limit per line pair to transmit data in parallel, thus enabling the system to acquire and transmit signal at 10 kHz.

Field programmable gate arrays (FPGAs) are attractive for a digital spectrometer due to its advantages of digital signal processing. However, how to improve the versatility of the spectrometer and increase the operating frequency of the digital shaper has gradually become a limitation that needs to be resolved in the FPGA-based spectrometer. A solution to improve the universality of the FPGA-based digital spectroscopy system is presented in this work, and the implementation of the real-time digital signal processing unit is improved to obtain a higher operating frequency, and then the optimal parameters of the digital trapezoidal shaper and the processing unit are also discussed through a series of experiments; finally, a FPGA-based digital spectrometer is developed. With the HPGe detector, the spectrometer achieves excellent energy resolution performance of 0.35% at 662 keV, 0.25% at 1173.2 keV, and 0.23% at 1332.5 keV.

现有便携式谱仪无法同时对α-β-γ射线进行测量,这使得相关人员对α-β-γ混合场景的评估与处理存在不便,因此我们研制了一套便携式α-β-γ谱仪以解决上述问题.谱仪采用PIPS探测器和LaBr3(Ce)探测器分别对α-β粒子和γ射线进行测量,获取高分辨的能谱.经测试,谱仪的α能量分辨率小于140 keV(5.486 MeV,0.1 atm),α表面发射率响应67.34％(241Am),β表面发射率响应19.13％(90Sr-90Y),γ能量分辨率小于3.4％(662 keV).因此谱仪可同时测量α-β-γ射线并获取高分辨的能谱,有助于相关人员对测量现场做出快速准确的评估与处理.