To meet the application demand for simultaneous structure inspection and elemental analysis, research on neutron imaging-driven prompt gamma activation analysis instrument is of great significance. Relying on the China Mianyang Research Reactor, the China Academy of Engineering Physics proposed the physical design of the PGAA -NT apparatus, carried out Monte Carlo simulations, signal commissioning and experimental tests, and successfully established an experimental facility that couples PGAA with neutron imaging. In terms of characterisation, the beam parameters, background features, Compton-suppression performance, wide-energy-range detection efficiency, and imaging spatial resolution of the instrument were accurately measured. The instrument exhibits the low background (full spectrum <200 cps at 1.5 x 108 ncm-2s-1), high energy resolution (2 keV at 1.332 MeV), high imaging spatial resolution ( <10 m) and millimetre-scale activated analysis volume. It provides a neutron measurement platform that combines three-dimensional structure detection with position-sensitive elemental analysis. This instrument fills the gap in China's PGAA-NT field, with performance reaching the international advanced level.

The fault diagnosis of T0 chopper bearings presents a significant challenge due to strong background noise and complex operating conditions. To address this, this paper proposes a novel diagnostic method by fusing Neural Blind Deconvolution (NNBD) and Sparse-Domain Kalman Filtering. The framework first employs NNBD to enhance incipient fault impulses from signals heavily corrupted by strong noise. Subsequently, features are extracted via sparse representation and then temporally optimized using a Kalman Filter in the sparse domain (SR-KF) to improve robustness and effectively track dynamic changes. Finally, a Bidirectional Long Short-Term Memory (Bi-LSTM) network classifies the optimized feature sequences for a precise diagnosis. Validated on the T0 chopper bearing experimental dataset, the proposed method achieves $99.96 \%$ accuracy, significantly outperforming standard deep learning models and providing an effective solution for high-precision rotating machinery.

The China Spallation Neutron Source (CSNS) is designed and constructed by the Institute of High Energy Physics, Chinese Academy of Sciences. The construction of CSNS includes an 80-MeV Linac, a 1.6-GeV Rapid Cycling Synchrotron (RCS), two beam transport lines, a solid target station of 100 kW, three initial neutron instruments and other utility facilities. Based on limited funding and lack of experience in the high-power proton accelerator and the spallation target, the CSNS design was optimized to an advanced user faculty to fulfill the urgent user demand, with a high performance/cost ratio, and to have the capability for the CSNS phase two project (CSNS-II) to increase the beam power to 500 kW with less investment. The CSNS construction started in October 2011, and finished in March 2018 on schedule, and reached the acceptance parameters. Since then, CSNS has been operating efficiently and stably. In March 2024, the proton beam power on the target was increased to 160 kW. More than 1700 user experiments have been carried out so far, indicating a strong user demand. The design, construction and commissioning of CSNS are presented in this paper.

The T0 chopper has the ability to remove the fast neutrons and high-energy gamma rays emitted at time zero of each pulse cycle. The multi-physics instrument of the China Spallation Neutron Source requires high epithermal neutron flux to obtain large momentum transfer, and the traditional single T0 chopper is a disadvantage for the transmission of epithermal neutrons in the long focusing guide. To solve this problem, the two counter-rotating T0 chopper design is proposed that can greatly improve the transmission efficiency of epithermal neutrons. The results of the beam experiment show that compared with the single T0 chopper operating at 50 Hz, the two counter-rotating T0 choppers at the same speed significantly improves the transmission efficiency of epithermal neutrons (especially the shorter wavelength neutrons). For example, when the two blades partially overlap, the transmission efficiencies of 0.05 & Aring;, 0.1 & Aring;, and 0.2 & Aring; wavelength neutrons are increased by 9.4, 4.7, and 4.6 times, respectively, which fully proves that the two counter-rotating T0 chopper design is reasonable, and the experimental results are in line with expectations. The design and application of two counter-rotating T0 choppers at the China Spallation Neutron Source is the first example of this in the world and can be applied to neutron spectrometers with high epithermal neutron flux requirements, and can also be extended to fields such as the energy selection of high-energy particles.

介绍了在新工科背景下利用大型仪器平台开展仪器分析实验教学的实践.以大型仪器平台为依托开设仪器分析实验,旨在提高学生动手能力,为后续的科研、就业打下坚实的基础.从师资队伍、运行机制、安全管理方面入手,建设高水平、智能化的大型仪器实践教学平台.在此基础上开展仪器分析实验,构建多学科交叉融合式课程体系,采用渗透式、智慧型教学方法,完善考核机制.实践表明,以大型仪器实践教学平台为依托开展仪器分析实验,可大大提高课程的教学质量,也锻炼了学生的动手能力,激发了学生的创新思维.

空间频域成像(spatial frequency domain imaging,SFDI)作为一种新颖的光学成像技术,主要采用结构光与特定的光传输模型相结合,在检测组织形态结构的同时能够提供组织的光学和生理参数信息,具有快速、宽场、无创、非接触、定量检测等特点,广泛应用于生物医学基础研究和临床诊疗等多个领域.本文就SFDI技术的基本原理和方法,以及其在临床常见疾病中的应用现状与研究进展作一综述,旨在为临床相关疾病的诊疗提供一种科学、新颖、可靠的评估方法.

引力波暴高能电磁对应体全天监测器(Gravitational wave high-energy Electromagnetic Counterpart All-sky Monitor,GECAM)是专门针对引力波伽马暴的研究机遇而提出的中国科学院空间科学(二期)先导专项卫星任务.GECAM卫星通过数传、遥测和北斗短报文3个通道下行触发、事例、并道、工程以及短报文等多种类型的数据,数据预处理过程需要对这些数据进行快速正确处理,以满足科学家对天文事件数据正确性和时效性的要求.针对GECAM卫星数据处理时效性要求高、数据连续完整、多信道数据融合处理以及触发事件数据切分等特点,对科学数据处理流程和天文警报信息处理流程进行了设计,概述了关键核心算法的思路与实现方法.卫星发射入轨后,数据预处理软件运行良好,正确性和及时性指标满足要求,为后续爱因斯坦探针(Einstein Probe,EP)卫星、中法天文卫星(Space-based multi-band astronomical Variable Objects Monitor,SVOM)等空间天文卫星开展数据预处理工作提供了参考.

A bandwidth chopper system was analytically designed in detail for a high-pressure neutron diffractometer at China spallation neutron source . A chopper system with two single-disk choppers and one double-disk chopper was proposed for this diffractometer based on the analysis of neutron time-of-flight method. Two modes, serving two scattering rooms, can be obtained by adjusting the rotational frequencies and the phase angles of the double-disk chopper. These analytically obtained parameters were further assessed by Monte-Carlo simulations via a package of Vitess, and the simulated results were in good agreement with theoretical expectations.

BackgroundBandwidth limiting (BWL) neutron chopper is one of the important devices installed on the time-of-flight neutron scattering spectrometer. The BWL chopper can select the wavelength range of neutrons and filter the pulse period overlapping background by means of the periodically rotating disk, so as to improve the signal-to-noise ratio.PurposeThis study aims to verify whether the performance of the BWL choppers installed on the neutron scattering spectrometer of China Spallation Neutron Source (CSNS) meets the engineering requirements; on the other hand, it can provide reference for the design of BWL chopper on to be constructed.MethodsFirst of all, based on the BWL chopper system installed on the general purpose powder diffractometer (GPPD) of CSNS, the performances of the BWL chopper were systematically studied by theoretical calculation. Then, Monte Carlo simulation software McStas was employed to calculate the performance of BWL with the physical parameters of neutron choppers. Finally, neutron beam experiments were carried out to measure the actual working performance of the BWL choppers.ResultsThe results show that the actual wavelength bandwidth is about 0.478 nm with less than 0.5% relative error to the target bandwidth of 0.48 nm. The BWL chopper has a significant effect on the filtering long-wave neutron background.ConclusionsThe BWL neutron chopper installed on GPPD of CSNS satisfies engineering needs, and can provide a reference for the design and improvement of the BWL in the neutron scattering spectrometer to be built in the future.

为了提升无人机机载光电侦察设备的目标识别距离,本文结合实际工程项目研制了适用于机载光电侦察设备的高速微扫描超分辨核心组件,在嵌入式平台GPU-TX2i上实现了图像实时超分辨重建.首先让微扫描核心组件按照预先设定的步长和频率进行微位移,获取四帧具有亚像素偏差的连续的低分辨率图像,然后使用基于概率分布的图像超分辨重建算法,将这四帧图像处理成一帧高分辨率的图像.实验结果表明,探测器输出的帧频为120 FPS、分辨率为640×512的低分辨图像序列经超分辨重建后,变成帧频为30 FPS、分辨率为1280×1024的图像序列,有效空间分辨率提升了78.2％,目标识别距离提升了43.3％.重建一帧高分辨率图像耗时约为33 ms,微扫描核心组件的微扫描响应时间小于1.0 ms,到位精度小于0.3μm(对应约0.03个像素)满足机载光电侦察设备对实时性和精度的要求.

固体浮力材料是现代深潜技术的重要组成部分之一,是深潜器设计装备的六大关键技术之一,也是海洋勘察及深海工程中最普遍应用的一种材料.这种材料主要是为深海装置提供浮力,以实现深海装置的悬浮定位,无动力上浮下潜,增大有效载荷,减少外型尺寸.固体浮力材料在应用到深水装备之前,需要对其关键性能指标进行检验,包括密度、高压吸水率和体积弹性模量等,以保证深水装备的安全使用.其中,体积弹性模量的检验则是一个技术难点.鉴于此,本文综述国内外固体浮力材料体积弹性模量的测试方法,包括仿真计算法、超声测量法和高压原位测试法,为水下装备设计开发人员提供参考.

BackgroundFermi chopper is the key equipment for monochromating the neutron beam in an inelastic neutron scattering spectrometer, and its performance will affect the resolution and counting rate of the spectrometer. The core component of Fermi chopper is neutron slit package, which is composed of neutron absorbing material and transparent material, and selects multiple single wavelength pulsed neutrons by high-speed rotation.PurposeThe study aims to design suitable slit packages for Fermi chopper prototype of China spallation neutron source (CSNS).MethodsAccording to the common experimental conditions of inelastic scattering, the development target of the Fermi chopper prototype was determined, then three typical slit packages were designed, and the feasibility of the design was verified by MCStas software simulation.ResultsThe simulation results show that: (1) the three kinds of slits can achieve a resolution of 2%~10% in the wavelength range of 0.02~0.50 nm, and the neutron decay rate and the slit packet transmittance meets the requirements; (2) the optimal incident wavelengths of the three kinds of slit packets at 600 Hz operating frequency are 0.165 nm, 0.040 nm and 0.023 nm respectively, which can be used in different wavelength ranges; (3) in the long wavelength band with better resolution, the slit packet can be used to reduce the velocity and improve the neutron pass rate.ConclusionsThe physical parameters for the prototype development of CSNS Fermi chopper are given by this study, it provides a reference for the slit package performance test of the future prototype, as well as the design of the neutron slit package of the Fermi chopper of the inelastic scattering spectrometer.

光学遥感图像海面舰船目标检测易受云雾,海岛,海杂波等复杂背景的干扰.本文提出了一种适用于复杂背景的舰船目标检测方法.首先为了克服目标尺度多变问题,利用视觉显著性生成多尺度显著图,然后使用基尼指数自适应选择最优显著图.考虑到全局阈值分割算法带来的漏检测问题,提出一种新的方案来分离目标和背景像素点.利用图像膨胀原理获取显著图的局部极大值点,然后使用k-means算法判断极大值点属于目标像素点还是背景像素点.接着对目标点邻近区域进行精细分割.最后引入基于径向梯度变换的旋转不变特征来进一步剔除虚警.实验结果表明,该算法能够成功检测出不同尺寸和方向的舰船目标,有效克服复杂背景的干扰.算法检测正确率93％,虚警率4％,优于其他舰船检测方法.

带宽限制中子斩波器是中国散裂中子源上飞行时间中子散射谱仪不可缺少的关键设备之一,谱仪获得的中子能谱波段范围由带宽斩波器决定,其主要原理是通过转盘的机械式阻挡来对中子束流进行斩波,选择到达样品的中子波长范围,从而起到降低背底、提高信噪比的作用.本文介绍了带宽限制中子斩波器的基本原理及其设计要求,重点阐述了带宽限制中子斩波器系统的设计方法,提出了斩波器系统配置布局的基本原则,并给出了带宽斩波器各物理参数的计算公式.带宽斩波器的配置数量应满足谱仪背底要求,去除背底的斩波器应放置在束线前端并使谱仪所需波段的中子无损失通过,带宽选取的斩波器则尽可能放置在束线后端.另外,满足同相位、同转速、同开口角和转动方向相反等条件的双盘斩波器可以在一定程度上提高中子通量.本文的工作可为中国散裂中子源二十台中子散射谱仪斩波器系统的物理设计提供指导和参考.

为研究材料的微观力学性能,设计了一套压痕测试装置.首先对关键零部件柔性铰链进行仿真分析,在最大量程时柔性铰链所受应力为49.85MPa,远小于柔性铰链的屈服强度;之后进行了整机仿真分析,装置固有频率达到527.71Hz,装置在实验过程中不会发生共振.然后校准了传感器的线性度,其线性度都达到0.99以上,满足精度要求.最后利用校准后的仪器开展铝合金研究工作,验证了铝合金在预拉力下材料微观力学性能的变化趋势.

针对工业机器人控制系统开放性较差、成本较高的问题,采用“DSP+FPGA+PC”的架构设计一个开放的、高性价比的工业机器人控制系统,其中以PC作为人机交互设备,以DSP和FPGA作为运动控制器.在完成控制系统的软硬件基础上,控制系统成功应用于自主设计的五自由度工业机器人,实现了注塑机的下料任务.具有较高的开放性、较低的成本、良好的性能和可操作性.

To soive the problem that the traditional electric-optical reconnaissance platform which is the exposed spherical structure increases the radar cross section of airplane dramatically, we propose a method using double reflectors rotating along the pitch axis and the azimuth axis to achieve wide-angle scanning. The conformal design with aircraft can be realized because of the small exposed size of this structure, and the cloaking performance of the aircraft is ensured. Based on the light reflection vector theory, we firstly study the imaging characteristics of the scanning system, and quantitatively analyze image rotation induced by the two reflectors rotating along the pitch axis and azimuth axis. The exact relationship between the degree and direction of the image rotation angle and the rotation angle and direction of the two reflectors is concluded. According to the above image rotation compensation theory, a bilateral control technique to eliminate the image rotation is put forward when the image de-rotation prism is controlled, and exactly cooperative motion of the scanning mirror and the de-rotation structure can be realized. Finally, imaging experiments are carried out to validate the proposed technique, and the results indicate that the image rotation is eliminated after de-rotation and high-precision optical image despun with root mean square less than 8' is achieved.

Dual field-of-view camera of 100mm and 400mm focal length was designed based on the given aerial camera optical design index,and the transfer function of long focal distance and full field is more than 0.3.In order to reduce the mass and improve the dynamic rigidity of aerial camera,the wall thickness and rib width of the main supporting structure in aerial camera were taken as the design variables.The natural frequency was ensured no less than a specific value,which was the constraint condition.The NX7.5 software was used to do the structure optimization design for the camera.The optimization result shows that the weight of zoom lens is reduced by 0.7 kg and the first-order natural frequency increases by 13 Hz.Modal analysis and thermal analysis were performed for the optimized camera,and the analysis results verify the correctness of the optimization design.Finally,the validity of the design was verified by the test.The optic-mechanical design of dual FOV aerial camera can efficiently ensure the performance of the whole system and can satisfy the requirement.

Aiming at the problem that the nonlinear load simulation algorithm of power electronic load is complex and low accuracy,a novel digital implementation method was presented.According to the rela-tions between the input voltage instantaneous value of three-phase uncontrolled rectifier bridge and DC voltage,as well as diode conduction conditions,the decision conditions of seven working stages were got. The differential equation of different working stages was solved using backward difference method to get the input current of three-phase uncontrolled rectifier bridge.The results were as the command signals of the current loop control of simulation converter inαβcoordinate and resonant controller was used to track the reference current in the static coordinate.Simulation and experimental results show that the proposed method simulates three-phase uncontrolled rectifier bridge with the characteristics of simple calculation, fast response and high accuracy.