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Detonation product analysis and the paradoxical performance mechanism of TKX-50:High detonation velocity with low metal acceleration
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作者 Kaiyuan Tan Yaqi Zhao +10 位作者 Qin Liu Lixiao Hao Yushi Wen Chunliang Ji Sha Yang Haoxu Wang Luchuan Jia Jiahui Liu Zhuoping Duan Yong Han Fenglei Huang 《Defence Technology(防务技术)》 2025年第4期255-266,共12页
This study investigates the paradoxical detonation behavior of TKX-50,a nitrogen-rich energetic material,exhibiting higher detonation velocities but lower metal acceleration ability compared to HMX.Through experimenta... This study investigates the paradoxical detonation behavior of TKX-50,a nitrogen-rich energetic material,exhibiting higher detonation velocities but lower metal acceleration ability compared to HMX.Through experimental measurements and theoretical calculations,we propose a novel three-factor competition mechanism to explain this phenomenon.TKX-50-based PBX formulations achieved detonation velocities up to 9100 m/s,surpassing HMX-based counterparts.However,cylinder expansion tests revealed a 15%reduction in metal acceleration ability.Thermochemical measurements showed lower detonation heat for TKX-50(4900 J/g)versus HMX(5645 J/g).Our mechanism involves:(1)compositional effects prevailing at high pressures;(2)Energy release becoming essential as pressure drops;(3)Pressure-dependent product composition evolution functioning at low pressure.VLW code calculations unveiled a"crossover"in Hugoniot curves,lending support to this mechanism.This study furnishes a new framework for comprehending the performance of nitrogen-rich energetic materials,with significant implications for the design and optimization of future high-energy density materials. 展开更多
关键词 TKX-50 Nitrogen-rich explosives Detonation velocity Metal acceleration Detonation product
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Radial acceleration estimation of multiple high maneuvering targets 被引量:2
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作者 Shuyi Jia Guohong Wang Shuncheng Tan 《Journal of Systems Engineering and Electronics》 SCIE EI CSCD 2014年第2期183-193,共11页
The acceleration of a high maneuvering target in signal processing is helpful to enhance the performance of the tracker and facilitate the classification of targets. At present, most of the research on acceleration es... The acceleration of a high maneuvering target in signal processing is helpful to enhance the performance of the tracker and facilitate the classification of targets. At present, most of the research on acceleration estimation is carried out in cases of a single target with time-frequency analysis methods such as fractional Fourier transform (FRFT), Hough-ambiguity transform (HAT), and Wigner-Vil e distribution (WVD), which need to satisfy enough time duration and sampling theorem. Only one reference proposed a method of acceleration estimation for multiple targets based on modified polynomial phase transform (MPPT) in the lin-ear frequency modulation (LFM) continuous-wave (CW) radar. The method of acceleration estimation for multiple targets in the pulse Doppler (PD) radar has not been reported so far. Compressive sensing (CS) has the advantage of sampling at a low rate and short duration without sacrificing estimation performance. There-fore, this paper proposes a new method of acceleration estimation for multiple maneuvering targets with the unknown number based on CS with pulse Doppler signals. Simulation results validate the effectiveness of the proposed method under several conditions with different duration, measurement numbers, signal to noise ra-tios (SNR), and regularization parameters, respectively. Simulation results also show that the performance of the proposed method is superior to that of FRFT and HAT in the condition of multiple targets. 展开更多
关键词 radial acceleration compressive sensing (CS) highmaneuvering targets fractional Fourier transform (FRFT) Hough-ambiguity transform (HAT).
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NSHV trajectory prediction algorithm based on aerodynamic acceleration EMD decomposition 被引量:8
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作者 LI Fan XIONG Jiajun +2 位作者 LAN Xuhui BI Hongkui CHEN Xin 《Journal of Systems Engineering and Electronics》 SCIE EI CSCD 2021年第1期103-117,共15页
Aiming at the problem of gliding near space hypersonic vehicle(NSHV)trajectory prediction,a trajectory prediction method based on aerodynamic acceleration empirical mode decomposition(EMD)is proposed.The method analyz... Aiming at the problem of gliding near space hypersonic vehicle(NSHV)trajectory prediction,a trajectory prediction method based on aerodynamic acceleration empirical mode decomposition(EMD)is proposed.The method analyzes the motion characteristics of the skipping gliding NSHV and verifies that the aerodynamic acceleration of the target has a relatively stable rule.On this basis,EMD is used to extract the trend of aerodynamic acceleration into multiple sub-items,and aggregate sub-items with similar attributes.Then,a prior basis function is set according to the aerodynamic acceleration stability rule,and the aggregated data are fitted by the basis function to predict its future state.After that,the prediction data of the aerodynamic acceleration are used to drive the system to predict the target trajectory.Finally,experiments verify the effectiveness of the method.In addition,the distribution of prediction errors in space is discussed,and the reasons are analyzed. 展开更多
关键词 hypersonic vehicle trajectory prediction empirical mode decomposition(EMD) aerodynamic acceleration
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Effects of nano-sized aluminum on detonation characteristics and metal acceleration for RDX-based aluminized explosive 被引量:8
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作者 Dan-yang Liu Pin Zhao +2 位作者 Serene Hay-Yee Chan Huey Hoon Hng Lang Chen 《Defence Technology(防务技术)》 SCIE EI CAS CSCD 2021年第2期327-337,共11页
Nano-sized aluminum(Nano-Al)powders hold promise in enhancing the total energy of explosives and the metal acceleration ability at the same time.However,the near-detonation zone effects of reaction between Nano-Al wit... Nano-sized aluminum(Nano-Al)powders hold promise in enhancing the total energy of explosives and the metal acceleration ability at the same time.However,the near-detonation zone effects of reaction between Nano-Al with detonation products remain unclear.In this study,the overall reaction process of 170 nm Al with RDX explosive and its effect on detonation characteristics,detonation reaction zone,and the metal acceleration ability were comprehensively investigated through a variety of experiments such as the detonation velocity test,detonation pressure test,explosive/window interface velocity test and confined plate push test using high-resolution laser interferometry.Lithium fluoride(LiF),which has an inert behavior during the explosion,was used as a control to compare the contribution of the reaction of aluminum.A thermochemical approach that took into account the reactivity of aluminum and ensuing detonation products was adopted to calculate the additional energy release by afterburn.Combining the numerical simulations based on the calculated afterburn energy and experimental results,the parameters in the detonation equation of state describing the Nano-Al reaction characteristics were calibrated.This study found that when the 170 nm Al content is from 0%to 15%,every 5%increase of aluminum resulted in about a 1.3%decrease in detonation velocity.Manganin pressure gauge measurement showed no significant enhancement in detonation pressure.The detonation reaction time and reaction zone length of RDX/Al/wax/80/15/5 explosive is 64 ns and 0.47 mm,which is respectively 14%and 8%higher than that of RDX/wax/95/5 explosive(57 ns and 0.39 mm).Explosive/window interface velocity curves show that 170 nm Al mainly reacted with the RDX detonation products after the detonation front.For the recording time of about 10 ms throughout the plate push test duration,the maximum plate velocity and plate acceleration time accelerated by RDX/Al/wax/80/15/5 explosive is 12%and 2.9 ms higher than that of RDX/LiF/wax/80/15/5,respectively,indicating that the aluminum reaction energy significantly increased the metal acceleration time and ability of the explosive.Numerical simulations with JWLM explosive equation of state show that when the detonation products expanded to 2 times the initial volume,over 80%of the aluminum had reacted,implying very high reactivity.These results are significant in attaining a clear understanding of the reaction mechanism of Nano-Al in the development of aluminized explosives. 展开更多
关键词 Nano-sized aluminum Detonation reaction zone Explosive metal acceleration Thermodynamic equilibrium calculation Laser interferometry
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Automatic detection of respiratory rate from electrocardiogram,respiration induced plethysmography and 3D acceleration signals 被引量:3
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作者 刘官正 吴丹 +2 位作者 梅占勇 朱青松 王磊 《Journal of Central South University》 SCIE EI CAS 2013年第9期2423-2431,共9页
Respiratory monitoring is increasingly used in clinical and healthcare practices to diagnose chronic cardio-pulmonary functional diseases during various routine activities.Wearable medical devices have realized the po... Respiratory monitoring is increasingly used in clinical and healthcare practices to diagnose chronic cardio-pulmonary functional diseases during various routine activities.Wearable medical devices have realized the possibilities of ubiquitous respiratory monitoring,however,relatively little attention is paid to accuracy and reliability.In previous study,a wearable respiration biofeedback system was designed.In this work,three kinds of signals were mixed to extract respiratory rate,i.e.,respiration inductive plethysmography(RIP),3D-acceleration and ECG.In-situ experiments with twelve subjects indicate that the method significantly improves the accuracy and reliability over a dynamic range of respiration rate.It is possible to derive respiration rate from three signals within mean absolute percentage error 4.37%of a reference gold standard.Similarly studies derive respiratory rate from single-lead ECG within mean absolute percentage error 17%of a reference gold standard. 展开更多
关键词 respiration inductive plethysmography respiratory rate ELECTROCARDIOGRAM 3D acceleration activity
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On the continued acceleration of bomb casing fragments following casing fracture 被引量:4
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作者 Michael D.HUTCHINSON David W.PRICE 《Defence Technology(防务技术)》 SCIE EI CAS 2014年第2期211-218,共8页
It has been said that,once a bomb casing has fractured, "detonation gases will then stream around the fragments or bypass them,and the acceleration process stops there." However,while apparently copious gas ... It has been said that,once a bomb casing has fractured, "detonation gases will then stream around the fragments or bypass them,and the acceleration process stops there." However,while apparently copious gas flow through casing fractures indicates some pressure release,it is also an indication of significant gas drive pressure,post casing fracture.This paper shows two approaches to the problem of calculating the actual loss of drive.One presents first-order analytical calculations,in cylindrical geometry,of pressure loss to the inside surface of a fractured casing.The second shows the modelling of a selected example in the CTH code.Both approaches reveal that gas escape,while occurring at its own soundspeed relative to the adjacent casing fragments,has to compete with rapid radial expansion of the casing.Together with some historic experiments now publicly available,our calculations indicate that post-fracture casing fragment acceleration is,for most systems,unlikely to be reduced significantly. 展开更多
关键词 壳体破裂 外壳 炸弹 气体逸出 压力损失 计算表 加速过程 压力释放
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Uniformity Control of Scanned Beam in 300 MeV Proton and Heavy Ion Accelerator Complex at SESRI 被引量:1
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作者 HOU Lingxiao YUAN Youjin +10 位作者 SHEN Guodong RUAN Shuang LIU Jie ZHU Yunpeng WANG Geng GUO Hongliang LYU Mingbang GAO Daqing XU Zhiguo SHENG Lina YANG Jiancheng 《原子能科学技术》 EI CAS CSCD 北大核心 2024年第4期705-713,共9页
In recent years,heavy ion accelerator technology has been rapidly developing worldwide and widely applied in the fields of space radiation simulation and particle therapy.Usually,a very high uniformity in the irradiat... In recent years,heavy ion accelerator technology has been rapidly developing worldwide and widely applied in the fields of space radiation simulation and particle therapy.Usually,a very high uniformity in the irradiation area is required for the extracted ion beams,which is crucial because it directly affects the experimental precision and therapeutic effect.Specifically,ultra-large-area and high-uniformity scanning are crucial requirements for spacecraft radiation effects assessment and serve as core specification for beamline terminal design.In the 300 MeV proton and heavy ion accelerator complex at the Space Environment Simulation and Research Infrastructure(SESRI),proton and heavy ion beams will be accelerated and ultimately delivered to three irradiation terminals.In order to achieve the required large irradiation area of 320 mm×320 mm,horizontal and vertical scanning magnets are used in the extraction beam line.However,considering the various requirements for beam species and energies,the tracking accuracy of power supplies(PSs),the eddy current effect of scanning magnets,and the fluctuation of ion bunch structure will reduce the irradiation uniformity.To mitigate these effects,a beam uniformity optimization method based on the measured beam distribution was proposed and applied in the accelerator complex at SESRI.In the experiment,the uniformity is successfully optimized from 75%to over 90%after five iterations of adjustment to the PS waveforms.In this paper,the method and experimental results were introduced. 展开更多
关键词 heavy ion accelerator beam uniformity scanning magnet MIC
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Acceleration Feedback Enhanced H_∞Disturbance Attenuation Control for a Class of Nonlinear Underactuated Vehicle Systems 被引量:3
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作者 HE Yu-Qing HAN Jian-Da 《自动化学报》 EI CSCD 北大核心 2008年第5期558-564,共7页
在这篇论文,一个概括加速反馈控制(声频抗流圈) 设计方法,命名声频抗流圈提高了 H ∞控制器,为两个被建议完整激活并且在激活的非线性的自治车辆系统下面。声频抗流圈基于已知的动力学作为柔韧的改进被设计到正常控制。首先,以便拒... 在这篇论文,一个概括加速反馈控制(声频抗流圈) 设计方法,命名声频抗流圈提高了 H ∞控制器,为两个被建议完整激活并且在激活的非线性的自治车辆系统下面。声频抗流圈基于已知的动力学作为柔韧的改进被设计到正常控制。首先,以便拒绝不确定性和外部骚乱,线性 prefilter 在新声频抗流圈设计方法被使用在正常声频抗流圈代替高获得。然后,背走算法被用于 AFC 设计在激活的系统下面。两个的分析在有限获得 L2 稳定性显示出的频率领域和输入产量的骚乱变细新控制器设计方法是适用的。最后,模拟关于无人的模型直升飞机的追踪的控制被进行。结果与没有声频抗流圈,追踪的控制获得验证新方法的可行性的那些相比。 展开更多
关键词 干扰弱化 加速反馈控制 非线性H∞控制 自动控制系统
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Online Minimum-acceleration Trajectory Planning with the Kinematic Constraints 被引量:2
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作者 WANG Ying-Shi 《自动化学报》 EI CSCD 北大核心 2014年第7期1328-1338,共11页
关键词 运动规划 约束规划 机器人系统 充分必要条件 加加速度 自由度 轨迹规划 运动约束
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Experimental study on the accumulative effect of multiple pulses on acceleration sensor
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作者 Jie Shen Yong He +4 位作者 Xu-chao Pan Zhong Fang Hong Chen Wan-li Zhang Yun-lei Shi 《Defence Technology(防务技术)》 SCIE EI CAS CSCD 2022年第5期772-780,共9页
Intentional electromagnetic interference is a serious threat to the safety of electronic devices. Multiple electromagnetic pulses will be coupled and transmitted to electronic devices through the cables.Accumulative e... Intentional electromagnetic interference is a serious threat to the safety of electronic devices. Multiple electromagnetic pulses will be coupled and transmitted to electronic devices through the cables.Accumulative effects are generated, which make it easier for damage to occur in the electronic devices. In this article, the working principle of micro-silicon acceleration sensors is introduced. The accumulative effects of multiple pulses on acceleration sensors is studied by a large number of injection experiments.The accumulation trends of multiple pulses with different pulse numbers and intervals are analyzed. The damaged structures inside abnormal sensor amplifiers were observed via optical microscopy and scanning electron microscopy. The experimental results show that the accumulative effect is strengthened with increased pulse number or decreased pulse interval, and the threshold voltage for multiple pulses on the acceleration sensor decreases. The threshold voltage for a single pulse is 321.57 V. When the pulse interval is 1 μs and the pulse number is 5, the threshold voltage for multiple pulses is 163.42 V,which is reduced by 49.12% compared with a single pulse. These results provide a reference for the damage design of electromagnetic pulse weapons. 展开更多
关键词 Accumulative effect Multiple pulses Injection experiment acceleration sensor Threshold voltage
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Distribution of acceleration and empirical formula for calculating maximum acceleration of rockfill dams
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作者 周晖 李俊杰 康飞 《Journal of Central South University》 SCIE EI CAS 2010年第3期642-647,共6页
To find the distribution patterns of dynamic amplification coefficients for dams subjected to earthquake, 3D seismic responses of concrete-faced rockfill dams with different heights and different shapes of river valle... To find the distribution patterns of dynamic amplification coefficients for dams subjected to earthquake, 3D seismic responses of concrete-faced rockfill dams with different heights and different shapes of river valley were analyzed by using the equivalent-linear model. Statistical analysis was also made to the seismic coefficient, and an empirical formula for calculating the maximum acceleration was provided. The results indicate that under the condition of the same dam height and the same base acceleration excitations, with the increase of the river valley width, the position of the maximum acceleration on the axis of the top of the dam moves from the center to the riversides symmetrically. For the narrow valleys, the maximum acceleration occurs in the middle of the axis at the top of the dam; for wide valleys the maximum acceleration appears near the riversides. The result negates the application of 2D dynamical computation for wide valleys, and shows that for the seismic response of high concrete-faced rockfill dams, the seismic coefficient along the axis should be given, except for that along the dam height. Seismic stability analysis of rockfill dams using pseudo-static method can be modified according to the formula. 展开更多
关键词 concrete-faced rockfill dam 3D dynamical response analysis equivalent-linear method acceleration seismic coefficient statistical analysis
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Relationship between critical seismic acceleration coefficient and static factor of safety of 3D slopes
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作者 SHI He-yang CHEN Guang-hui 《Journal of Central South University》 SCIE EI CAS CSCD 2021年第5期1546-1554,共9页
Many analytical methods have been adopted to estimate the slope stability by providing various stability numbers,e.g.static safety of factor(static FoS)or the critical seismic acceleration coefficient,while little att... Many analytical methods have been adopted to estimate the slope stability by providing various stability numbers,e.g.static safety of factor(static FoS)or the critical seismic acceleration coefficient,while little attention has been given to the relationship between the slope stability numbers and the critical seismic acceleration coefficient.This study aims to investigate the relationship between the static FoS and the critical seismic acceleration coefficient of soil slopes in the framework of the upper-bound limit analysis.Based on the 3D rotational failure mechanism,the critical seismic acceleration coefficient using the pseudo-static method and the static FoS using the strength reduction technique are first determined.Then,the relationship between the static FoS and the critical seismic acceleration coefficient is presented under considering the slope angleβ,the frictional angleφ,and the dimensionless coefficients B/H and c/γH.Finally,a fitting formula between the static FoS and the critical seismic acceleration coefficient is proposed and validated by analytical and numerical results. 展开更多
关键词 static safety of factor critical seismic acceleration coefficient upper-bound limit analysis 3D rotational failure mechanism
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Investigation on the Effect of Lubricating-Oil Temperature on Deceleration Process of the Diesel Engine 被引量:1
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作者 ZHANG Geng-yun WANG Xu-dong CHEN Man-qing HE Lai-long WANG Pu-kai 《Defence Technology(防务技术)》 CAS 2009年第4期251-255,共5页
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基于FPGA的MobileNetV1目标检测加速器设计 被引量:2
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作者 严飞 郑绪文 +2 位作者 孟川 李楚 刘银萍 《现代电子技术》 北大核心 2025年第1期151-156,共6页
卷积神经网络是目标检测中的常用算法,但由于卷积神经网络参数量和计算量巨大导致检测速度慢、功耗高,且难以部署到硬件平台,故文中提出一种采用CPU与FPGA融合结构实现MobileNetV1目标检测加速的应用方法。首先,通过设置宽度超参数和分... 卷积神经网络是目标检测中的常用算法,但由于卷积神经网络参数量和计算量巨大导致检测速度慢、功耗高,且难以部署到硬件平台,故文中提出一种采用CPU与FPGA融合结构实现MobileNetV1目标检测加速的应用方法。首先,通过设置宽度超参数和分辨率超参数以及网络参数定点化来减少网络模型的参数量和计算量;其次,对卷积层和批量归一化层进行融合,减少网络复杂性,提升网络计算速度;然后,设计一种八通道核间并行卷积计算引擎,每个通道利用行缓存乘法和加法树结构实现卷积运算;最后,利用FPGA并行计算和流水线结构,通过对此八通道卷积计算引擎合理的复用完成三种不同类型的卷积计算,减少硬件资源使用量、降低功耗。实验结果表明,该设计可以对MobileNetV1目标检测进行硬件加速,帧率可达56.7 f/s,功耗仅为0.603 W。 展开更多
关键词 卷积神经网络 目标检测 FPGA MobileNetV1 并行计算 硬件加速
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全球变暖加速和气候极端化——2024年中国气候研究重大进展速评 被引量:7
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作者 王会军 孙建奇 +2 位作者 陈活泼 马洁华 段明铿 《大气科学学报》 北大核心 2025年第1期1-7,共7页
全球气候正在加速变暖,2023、2024年连续刷新历史高温纪录,2024年较工业革命前升温达1.55℃。“全球沸腾时代”已至,与之伴随的是极端天气事件频发,2000—2019年气象灾害损失较之前20年翻倍。应对气候变化亟须科学突破,国际学术界聚焦... 全球气候正在加速变暖,2023、2024年连续刷新历史高温纪录,2024年较工业革命前升温达1.55℃。“全球沸腾时代”已至,与之伴随的是极端天气事件频发,2000—2019年气象灾害损失较之前20年翻倍。应对气候变化亟须科学突破,国际学术界聚焦气候预测与极端事件等七大挑战。中国气候研究委员会作为中国-国际气候研究交流的桥梁,评选出了2024年十大气候研究进展:东北亚极端增温机制、气溶胶气候效应复杂性、全球降水变率增强、梅雨特征演变、降水系统扁平化、青藏高原水-热-碳耦合、北太平洋海温影响、大西洋-太平洋盐度差异、深时环流与ENSO、AI气候预测系统等。这些成果突显气候研究的前沿领域、跨学科性与社会价值。未来气候领域的研究热点将聚焦全球变暖加速、气候极端化、新北极和青藏高原新时代、气候系统多圈层耦合、气候系统预测与人工智能、气候变化风险与应对等方面,以更好地为防灾减灾、应对气候变化风险、全球气候治理提供科学支撑。 展开更多
关键词 全球变暖加速 气候极端化 新北极和青藏高原新时代 气候预测与AI
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中国内地及邻区8.0级左右地震周期划分、主体活动区迁移与地球自转加减速的关系
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作者 朱红彬 李红 +1 位作者 胡乐银 陈宇轩 《大地测量与地球动力学》 北大核心 2025年第10期997-1005,共9页
通过研究中国内地及邻近区域M S≥7.8地震周期的划分和主体活动区的迁移,结合地球自转速度的加速与减速变化,探讨研究区8.0级左右地震活动的时空规律及其驱动机制,得出以下结论:1)1879年以来,研究区经历了6个8.0级左右地震的活跃幕,其中... 通过研究中国内地及邻近区域M S≥7.8地震周期的划分和主体活动区的迁移,结合地球自转速度的加速与减速变化,探讨研究区8.0级左右地震活动的时空规律及其驱动机制,得出以下结论:1)1879年以来,研究区经历了6个8.0级左右地震的活跃幕,其中第2活跃幕的主体活动区位于帕米尔-贝加尔湖地震带,第3活跃幕位于青藏高原东北缘,第4活跃幕位于青藏高原东南缘,第5活跃幕位于云南和华北地区,第6活跃幕则位于青藏高原内部的巴颜喀拉地块周边,目前可能正处于一个新的活跃幕起始阶段。2)1867年以来,地球自转日长变化曲线可划分为4个加速-减速幕和16个加速-减速段,构造应力场的S向叠加减速变化有利于帕米尔-贝加尔湖地震带发生8.0级左右地震,而NE向构造应力场叠加加速变化则有利于青藏高原周缘及内部发生8.0级左右地震;地球自转从加速段向减速段的转变导致青藏高原及周边构造应力场从NE向主导转变为局部恢复近NS向,是第3、第4、第6活跃幕在加速段起始至减速段结束的主要驱动因素。3)中国内地及邻近区域百年来的构造应力场经历了从NS向到NE向再到NE偏E向的顺时针偏转,这一过程可能与地球自转在1913年以前的大减速和之后总体加速的过程相关。此外,这一过程尚未结束,目前未出现类似第2活跃幕8.0级左右地震集中爆发的迹象,但应警惕青藏高原构造应力场可能继续向NE偏E向偏转,未来不排除出现新的主体活动区的可能。 展开更多
关键词 中国内地及邻区 8.0级左右地震 地震周期划分 主体活动区 地球自转加速和减速变化
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中国原子能科学研究院核物理加速器设施及技术应用
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作者 唐兵 杨新宇 +13 位作者 阚朝新 陈红涛 何明 吴振东 崔保群 陈立华 马鹰俊 马瑞刚 黄青华 马燮 陈浩南 彭朝华 柳卫平 郭冰 《原子能科学技术》 北大核心 2025年第9期1805-1821,共17页
中国原子能科学研究院长期开展放射性核束产生技术、低能高压加速器技术、串列加速器技术及高频型加速器研究,建立了HI-13串列加速器、超导直线加速器、多粒子可变能量回旋加速器、600 kV高压倍加器、北京放射性核束装置在线同位素分离... 中国原子能科学研究院长期开展放射性核束产生技术、低能高压加速器技术、串列加速器技术及高频型加速器研究,建立了HI-13串列加速器、超导直线加速器、多粒子可变能量回旋加速器、600 kV高压倍加器、北京放射性核束装置在线同位素分离器、锦屏地下强流加速器等核物理研究装置,有力支撑了我国基础核物理事业及相关领域的发展,放射性核束产额、高压加速器性能指标均达到国际先进水平。中国原子能科学研究院还基于核物理加速器技术,开发了小型串列加速器、小型中子发生器、加速器质谱、离子注入机、核孔膜生产等产业项目,并初步实现产品型谱化,其中小型串列加速器实现了国内自主可控。 展开更多
关键词 加速器 在线同位素分离器 中子发生器 加速器质谱 串列加速器 高压倍加器 核孔膜
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技术时代教师的数字压力何以调适 被引量:3
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作者 饶爱京 万昆 李荣辉 《中国电化教育》 北大核心 2025年第3期118-125,共8页
探究技术时代教师的数字压力如何,从而为推进教育数字化转型、提升技术赋能教师工作效能提供有效的循证依据,该研究基于2122名教师的问卷调查数据,对教师数字压力现状、不同维度教师数字压力差异、教师数字压力的影响因素进行了分析。... 探究技术时代教师的数字压力如何,从而为推进教育数字化转型、提升技术赋能教师工作效能提供有效的循证依据,该研究基于2122名教师的问卷调查数据,对教师数字压力现状、不同维度教师数字压力差异、教师数字压力的影响因素进行了分析。研究发现,技术时代教师存在着一定的数字压力,技术时代教师数字压力表现为“内升”和“外载”两种形态,教师工作负担显著正向影响数字压力,且工作负担均能通过数字压力间接影响教师行为意向。为此,调适技术时代的教师压力,需要构建教师数字素养提升的保障体系,从加速理论和驯化理论理解教师在教育数字化转型中的作用,推动构建良好的教育数字化生态。该研究结果为理解技术时代教师的数字压力提供了循证依据,也为推动教育数字化转型提供了新的研究视角。 展开更多
关键词 教师数字压力 调适 教育数字化转型 加速理论
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计及铁心非线性的变压器空间动态磁场加速计算方法 被引量:1
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作者 司马文霞 孙佳琪 +3 位作者 杨鸣 邹德旭 彭庆军 王劲松 《电工技术学报》 北大核心 2025年第5期1559-1574,共16页
快速获得变压器空间磁场动态分布是构建变压器数字孪生体的基础之一,然而现有快速计算方法难以快速、准确地获得铁心饱和工况下的磁场分布特性。因此,该文提出了计及铁心非线性的变压器空间动态磁场加速计算方法。首先,构建变压器电磁... 快速获得变压器空间磁场动态分布是构建变压器数字孪生体的基础之一,然而现有快速计算方法难以快速、准确地获得铁心饱和工况下的磁场分布特性。因此,该文提出了计及铁心非线性的变压器空间动态磁场加速计算方法。首先,构建变压器电磁场路耦合仿真模型,对关键变量进行参数化扫描,仿真获得不同非线性工况下的大量磁场数据,构建涉及铁心非线性工况的主磁通和漏磁通数据集;其次,提出融合卷积神经网络(CNN)和长短期记忆网络(LSTM)的双分支深度学习模型,训练提取磁场数据的空间和时间特征,解决主、漏磁通差异大造成的模型训练难题;最后,利用模型获得输入电压、电流与内部空间磁场分布的非线性映射关系,实现空间动态磁场的加速计算,为变压器数字孪生体的构建提供了快速获得磁场数据的方法。 展开更多
关键词 非线性 卷积神经网络 长短期记忆网络 磁场 加速计算
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结构变形对高超声速可变形减速器的动态稳定性影响分析
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作者 时晓天 张桂茹 +2 位作者 吕蒙 赵渊 高军 《航天返回与遥感》 北大核心 2025年第1期11-20,共10页
文章针对高超声速可变形减速器的飞行稳定性预测及回收着陆需求,研究表面结构变形对减速器气动特性的影响效应,重点分析了高度10~50 km、Ma=0.15~4.6关键速域内的静、动态气动特性变化。文章采用求解雷诺平均Navier-Stokes方程(Reynolds... 文章针对高超声速可变形减速器的飞行稳定性预测及回收着陆需求,研究表面结构变形对减速器气动特性的影响效应,重点分析了高度10~50 km、Ma=0.15~4.6关键速域内的静、动态气动特性变化。文章采用求解雷诺平均Navier-Stokes方程(Reynolds average Navier-Stokes,RANS)的数值模拟方法,获得了有无表面结构变形减速器的流场和气动参数。定常计算结果表明:变形效应导致飞行器迎风面存在局部的小尺度流动分离,变形后外形的气动阻力增加。结合刚性动网格技术的俯仰强迫振动,计算结果表明:减速器的动态稳定性受到迎风面高压及背风面分离涡结构的共同作用,迎风面的高气动压力载荷占主导作用,使得减速器的动态稳定性增强;背风面的涡结构导致动态稳定性减弱;轴对称分布的表面结构变形整体上增强了减速器的动态稳定性。 展开更多
关键词 回收着陆 高超声速可变形减速器 结构变形 动态稳定性 强迫振动 动导数
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