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Penetration-deflagration coupling damage performance of rod-like reactive shaped charge penetrator impacting thick steel plates 被引量:1
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作者 Tao Sun Haifu Wang +3 位作者 Shipeng Wang Jie Gong Wenhao Qiu Yuanfeng Zheng 《Defence Technology(防务技术)》 2025年第7期152-164,共13页
The penetration-deflagration coupling damage performance of rod-like reactive shaped charge pene-trator(RRSCP)impacting thick steel plates is investigated by theoretical analysis and experiments.A penetration-deflagra... The penetration-deflagration coupling damage performance of rod-like reactive shaped charge pene-trator(RRSCP)impacting thick steel plates is investigated by theoretical analysis and experiments.A penetration-deflagration coupling damage model is developed to predict the penetration depth and cratering diameter.Four type of aluminum-polytetrafluoroethylene-copper(Al-PTFE-Cu)reactive liners with densities of 2.3,2.7,3.5,and 4.5 g·cm^(-3) are selected to conduct the penetration experiments.The comparison results show that model predictions are in good agreement with the experimental data.By comparing the penetration depth and cratering diameter in the inert penetration mode and the penetration-deflagration coupling mode,the influence mechanism that the penetration-induced chemical response is unfavorable to penetration but has an enhanced cratering effect is revealed.From the formation characteristics,penetration effect and penetration-induced chemical reaction be-haviors,the influence of reactive liner density on the penetration-deflagration performance is further analyzed.The results show that increasing the density of reactive liner significantly increases both the kinetic energy and length of the reactive penetrator,meanwhile effectively reduces the weakened effect of penetration-induced chemical response,resulting in an enhanced penetration capability.However,due to the decreased diameter and potential energy content of reactive penetrator,the cratering capa-bility is weakened significantly. 展开更多
关键词 Reactive materials Al-PTFE composites Penetration model Damage effect
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Highly Stable,Antiferromagnetic MnN Films Grown by Molecular Beam Epitaxy
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作者 JI Zhuang XIAO Dongdong +2 位作者 GU Minghui MENG Meng GUO Jiandong 《真空科学与技术学报》 北大核心 2025年第8期664-672,共9页
High-quality antiferromagnetic(AFM)θ-phase manganese nitride(MnN)films were successfully grown on MgO(001)substrates by plasma-assisted molecular beam epitaxy.Structural analysis confirms the high-quality MnN film ha... High-quality antiferromagnetic(AFM)θ-phase manganese nitride(MnN)films were successfully grown on MgO(001)substrates by plasma-assisted molecular beam epitaxy.Structural analysis confirms the high-quality MnN film has a tetragonal distortion with a c/a ratio of~0.98.The film exhibits exceptional stability in both aqueous and ambient conditions,which is a crucial factor for practical applications.Electrical transport reveals its metallic behavior with an upturn at low temperatures,which could be attributed to the Kondo effect originated from nitrogen vacancy-induced magnetic impurities.Room temperature exchange bias has been demonstrated in a MnN/CoFeB heterostructure,verifying the AFM ordering of MnN.Considering its high Néel temperature~650 K,superior stability,and low-cost,this work highlights the epitaxial MnN films as a promising candidate for AFM spintronic applications. 展开更多
关键词 Molecular beam epitaxy Antiferromagnetic MnN thin film Stability Kondo effect Exchange bias
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趋磁细菌Magnetospirillum gryphiswaldense MSR-1对镉的生物吸附初步研究
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作者 曹振宇 涂晨 +3 位作者 刘颖 韩军超 邢倩雯 骆永明 《生态环境学报》 北大核心 2025年第1期99-107,共9页
趋磁细菌由于其独有的趋磁运动能力,展现出成为新型可回收生物吸附材料的潜力。但有关趋磁细菌对Cd(Ⅱ)的吸附去除应用研究仍非常有限,趋磁细菌对Cd(Ⅱ)的吸附特征与机理尚不明确。选用趋磁细菌模式菌株Magnetospirillum gryphiswaldens... 趋磁细菌由于其独有的趋磁运动能力,展现出成为新型可回收生物吸附材料的潜力。但有关趋磁细菌对Cd(Ⅱ)的吸附去除应用研究仍非常有限,趋磁细菌对Cd(Ⅱ)的吸附特征与机理尚不明确。选用趋磁细菌模式菌株Magnetospirillum gryphiswaldense MSR-1,采用扫描电子显微镜(SEM)对MSR-1吸附Cd(Ⅱ)前后的形态进行了表征;通过批吸附实验研究了不同溶液pH值、Cd(Ⅱ)初始浓度、细菌生物量和温度等反应条件对MSR-1吸附Cd(Ⅱ)的影响;利用动力学模型、等温吸附模型模拟了吸附过程;采用傅里叶变换红外光谱(FTIR)、顺序洗脱法等方法初步探究了MSR-1对Cd(Ⅱ)吸附的机理。结果表明,吸附Cd后的MSR-1菌体表面形貌改变并出现破损。MSR-1对Cd(Ⅱ)的吸附效率主要受pH、初始Cd(Ⅱ)浓度和细菌生物量等因素影响。当pH为8.0、Cd(Ⅱ)初始浓度为1mg·L^(-1)、温度为30℃、吸附时间为1h、细菌生物量(湿质量)为3.33g·L^(-1)时,MSR-1对Cd(Ⅱ)的吸附效率可达87.8%。Cd(Ⅱ)浓度在0.5-20mg·L^(-1)时,随着Cd(Ⅱ)浓度的升高,MSR-1对Cd(Ⅱ)的吸附量逐渐增大,最大吸附量达1.20 mg·g^(-1)。MSR-1对Cd(Ⅱ)的吸附过程遵循准二级动力学方程和Langmuir等温模型。羟基、酰胺I基团和羧基等基团参与了MSR-1吸附Cd(Ⅱ)的过程。MSR-1对Cd(Ⅱ)吸附机制可涉及物理吸附、离子交换、络合作用和胞内积累,其中离子交换作用为最主要的吸附机制,贡献占比为74.9%。综上,趋磁细菌MSR-1对Cd(Ⅱ)有较好的吸附去除能力,为未来作为有潜力的可回收生物吸附材料,用于Cd污染水体和土壤的生物修复提供数据支持和理论依据。 展开更多
关键词 趋磁细菌 生物吸附作用 离子交换 影响因子
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基于改进U-Net++模型的油菜pol TCMS温敏两系育性等级鉴定及温度育性关系的量化研究
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作者 李世鹏 陈才武 +3 位作者 张晶 吕恬 傅廷栋 易斌 《作物学报》 北大核心 2025年第6期1423-1434,共12页
油菜(Brassica napus L.)是全球重要的油料作物,其杂种优势的利用在提升产量与环境适应能力方面发挥了关键作用。温敏型波里马细胞质雄性不育系(pol TCMS)因其育性受温度影响,具备一系两用的独特优势,已成功应用于两系育种。雄蕊、雌蕊... 油菜(Brassica napus L.)是全球重要的油料作物,其杂种优势的利用在提升产量与环境适应能力方面发挥了关键作用。温敏型波里马细胞质雄性不育系(pol TCMS)因其育性受温度影响,具备一系两用的独特优势,已成功应用于两系育种。雄蕊、雌蕊长度是生产实践中进行育性等级划分的主要依据,然而育性等级的主观划分方法易受人为因素干扰,最终影响表型考察及精细定位的结果。为此,本研究提出了一种育性等级鉴定的新方法,即基于改进U-Net++深度学习模型的图像语义分割法。以pol TCMS温敏两系及pol CMS稳定不育系构建F2分离群体,首先,获取分离群体中不同育性等级花器官的图像,标注构建数据集;其次,选取U-Net++图像语义分割方法,通过优化编码器和解码器结构并引入通道注意力模块,提升模型的分割精度;最后,以不同育性等级的图像进行训练和测试。结果表明,改进后的模型在不同育性等级花器官的分割任务中,平均交并比为92.02%,精确率为98.94%,召回率为98.84%,F1分数为98.87%,优于其他分割模型方法,该模型能很好识别出不同育性等级的花器官。基于分割结果获得原位实际长度,与人工测量的长度相比,预测值与实测值的决定系数R^(2)为0.989,均方根误差(RMSE)为0.142 mm,Spearman相关系数为0.983,可以实现不同育性等级表型参数的准确测量。此外,通过分析量化温度与育性(雄蕊/雌蕊比值)的关系发现,育性随单花开花前9 d的温度变化而波动。本研究验证了温度对油菜育性的关键影响,为深入解析油菜温敏特性及相关基因定位研究提供了新方法和技术支持。 展开更多
关键词 油菜 Pol TCMS U-net++分割模型 温度 育性等级 基因定位
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Design and implementation of a high-performance miniaturized multi-layer magnetic shielding spherical shell with minimal pores based on target magnetic field
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作者 Wanqing Li Wei Li +2 位作者 Shaotao Qu Shuyi Zhang Jingyang Xu 《Defence Technology(防务技术)》 2025年第3期99-108,共10页
Achieving the spin-exchange relaxation-free(SERF)state in atomic comagnetometers(ACMs)necessitates a stable and weak magnetic environment.This paper presents the design of a miniaturized permalloy magnetic shielding s... Achieving the spin-exchange relaxation-free(SERF)state in atomic comagnetometers(ACMs)necessitates a stable and weak magnetic environment.This paper presents the design of a miniaturized permalloy magnetic shielding spherical shell(MSSS)with minimal apertures,tailored to meet these requirements.By employing a combination of analytical solutions and finite element analysis(FEA),we achieved superior magnetic shielding while maintaining a compact form factor.The analytical solution for the shielding factor indicated that a four-layer permalloy sphere shell with optimized air gaps was necessary.A numerical analysis model of the MSSS was developed and validated using COMSOL software,confirming the suitability of the air gaps.The size,shape,and orientation of the openings in the perforated sphere shell were meticulously designed and optimized to minimize residual magnetism.The optimal structure was fabricated,resulting in triaxial shielding factors of 47619,52631,and 21739,meeting the anticipated requirements.A comparison of simulation results with experimental tests demonstrated the efficacy of the design methodology.This study has significant implications for ultrasensitive magnetic field detection devices requiring weak magnetic field environments,such as atomic gyroscopes,magnetometers,atomic interferometers,and atomic clocks. 展开更多
关键词 Magnetic shielding Spherical shield Finite element analysis(FEA) Shielding effectiveness Spin-exchange relaxation-free(SERF) comagnetometer
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基于OneNET的棉田水肥一体化温湿度监测系统设计
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作者 杜婵婵 周润猛 李传戈 《新疆农机化》 2025年第3期25-27,38,共4页
水肥一体化技术在新疆棉花种植中应用广泛,但新疆地区降水分布严重不均,自动化施肥系统易发生水肥浪费现象,造成巨大的损失。为实现根据棉田温湿度状况进行水肥施用的要求,本文设计了一套棉田水肥一体化温湿度监测系统,系统运用数字温... 水肥一体化技术在新疆棉花种植中应用广泛,但新疆地区降水分布严重不均,自动化施肥系统易发生水肥浪费现象,造成巨大的损失。为实现根据棉田温湿度状况进行水肥施用的要求,本文设计了一套棉田水肥一体化温湿度监测系统,系统运用数字温湿度传感器SHT20采集棉田温湿度,搭配32位微控制器STM32F103RET6处理数据,通过OneNET云平台实现棉田温湿度数据可视化。试验结果表明,系统可以实现实时监测温湿度数据,并实现数据存储、历史数据查询及设备上云功能。 展开更多
关键词 棉田温湿度 设备云连接 Onenet云平台 实时监测
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基于PI-DeepONet模型的IGBT模块结温估算方法
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作者 项江鑫 霍思佳 +2 位作者 乐应波 杨程 崔昊杨 《半导体技术》 北大核心 2025年第7期746-755,共10页
时变高功率工况下,IGBT模块结温的实时准确估算是高效实施热管理策略的基础。但现有方法中,有限元分析(FEA)法难以实时响应,热网络模型法估算准确率低,两者均无法满足结温估算实时性和准确率的均衡性需求。针对这些问题,提出了一种基于... 时变高功率工况下,IGBT模块结温的实时准确估算是高效实施热管理策略的基础。但现有方法中,有限元分析(FEA)法难以实时响应,热网络模型法估算准确率低,两者均无法满足结温估算实时性和准确率的均衡性需求。针对这些问题,提出了一种基于物理约束深度算子网络(PI-DeepONet)模型的IGBT模块结温实时准确估算方法。首先,在算子网络的损失函数中引入物理约束,设计了具有物理约束的PI-DeepONet模型;随后,将FEA计算的IGBT模块热特性参数与时空位置信息作为输入对模型进行训练;最后,利用训练所得的最优算子估算模块结温。仿真结果表明,该模型兼顾了结温估算的准确率和实时性,能够适应复杂工况,为IGBT模块热管理策略的高效实施提供了可靠的理论支持与技术保障。 展开更多
关键词 IGBT 结温估算 物理约束深度算子网络(PI-DeepOnet)模型 有限元分析(FEA)法 热网络模型 热管理策略
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基于U-net神经网络的油浸式变压器绕组流-热耦合快速计算 被引量:4
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作者 刘云鹏 高艺倩 +4 位作者 刘刚 胡万君 王文浩 王博闻 高成龙 《中国电机工程学报》 EI CSCD 北大核心 2024年第7期2897-2909,I0032,共14页
该文针对采用传统数值方法进行大型油浸变压器绕组温升仿真时间较长的问题,提出一种基于U-net神经网络训练的快速计算方法,可以迅速地预测变压器绕组温升及热点。首先,根据流热耦合原理筛选输入变量,并运用流热耦合方法计算不同工况下... 该文针对采用传统数值方法进行大型油浸变压器绕组温升仿真时间较长的问题,提出一种基于U-net神经网络训练的快速计算方法,可以迅速地预测变压器绕组温升及热点。首先,根据流热耦合原理筛选输入变量,并运用流热耦合方法计算不同工况下的输出结果,并将之制作成训练集和测试集。同时,详细讨论3个对网络训练影响最显著的超参数;其次,将归一化后的训练集输入U-net神经网络进行训练,并设置超参数最佳组合;最后,将预测集输入训练好的模型进行预测计算及反归一化操作,预测绕组热点与Fluent仿真结果相差仅0.44 K,单次仿真时间从200 s缩短为0.07 s。预测结果与实验温度平均误差最大为2.31 K,最小为0.98 K,预测方差为0.31左右。结果表明:该方法可用于快速获得油浸式变压器绕组的温度及热点,可满足变压器温度热点数字孪生的实时性仿真要求。 展开更多
关键词 U-net神经网络 流热耦合 绕组温升 快速计算 数字孪生
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光伏型红外焦平面探测器NETD的理论计算和测试分析
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作者 毛京湘 孔金丞 +3 位作者 孔令磊 龚晓丹 黄俊博 马颖婷 《红外技术》 CSCD 北大核心 2024年第8期872-878,共7页
噪声等效温差(NETD)是表征红外焦平面探测器灵敏度的重要参数,除了器件本身的因素以外,与实际应用条件及测试条件密切相关。从红外焦平面探测器NETD的测试方法和流程出发,对光伏型红外焦平面探测器NETD的理论计算公式进行了推导,分析了... 噪声等效温差(NETD)是表征红外焦平面探测器灵敏度的重要参数,除了器件本身的因素以外,与实际应用条件及测试条件密切相关。从红外焦平面探测器NETD的测试方法和流程出发,对光伏型红外焦平面探测器NETD的理论计算公式进行了推导,分析了影响器件NETD的主要因素,对典型红外焦平面探测器在不同积分时间、不同电荷存储量、不同F数及半阱输出条件下的背景限NETD进行了理论计算及分析。在固定背景温度下,通过理论公式可从某一温差的NETD推算出不同温差的NETD,选择典型器件进行验证,从常规NETD测试结果推算出的一组NETD与相应温差下的实测结果符合较好,其中1 K温差的NETD推算结果已非常接近实际情况,可为热像仪系统应用提供参考。 展开更多
关键词 红外焦平面探测器 噪声等效温差(netD) 背景温度 积分时间 电荷存储量 半阱输出
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Self-organizing fuzzy clustering neural network and application to electronic countermeasures effectiveness evaluation 被引量:6
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作者 Li Zhisheng Li Junshan +1 位作者 Feng Fan Zhao Xin 《Journal of Systems Engineering and Electronics》 SCIE EI CSCD 2008年第1期119-124,共6页
A self-organizing fuzzy clustering neural network by combining the self-organizing Kohonen clustering network with the fuzzy theory is proposed. This network model is designed for the effectiveness evaluation of elect... A self-organizing fuzzy clustering neural network by combining the self-organizing Kohonen clustering network with the fuzzy theory is proposed. This network model is designed for the effectiveness evaluation of electronic countermeasures, which not only exerts the advantages of the fuzzy theory, but also has a good ability in machine learning and data analysis. The subjective value of sample versus class is computed by the fuzzy computing theory, and the classified results obtained by self-organizing learning of Kohonen neural network are represented on output layer. Meanwhile, the fuzzy competition learning algorithm keeps the similar information between samples and overcomes the disadvantages of neural network which has fewer samples. The simulation result indicates that the proposed algorithm is feasible and effective. 展开更多
关键词 fuzzy clusteringself-organizing neural network effectiveness evaluation
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IUKF neural network modeling for FOG temperature drift 被引量:4
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作者 Feng Zha Jiangning Xu +1 位作者 Jingshu Li Hongyang He 《Journal of Systems Engineering and Electronics》 SCIE EI CSCD 2013年第5期838-844,共7页
A novel neural network based on iterated unscented Kalman filter (IUKF) algorithm is established to model and com- pensate for the fiber optic gyro (FOG) bias drift caused by temperature. In the network, FOG tempe... A novel neural network based on iterated unscented Kalman filter (IUKF) algorithm is established to model and com- pensate for the fiber optic gyro (FOG) bias drift caused by temperature. In the network, FOG temperature and its gradient are set as input and the FOG bias drift is set as the expected output. A 2-5-1 network trained with IUKF algorithm is established. The IUKF algorithm is developed on the basis of the unscented Kalman filter (UKF). The weight and bias vectors of the hidden layer are set as the state of the UKF and its process and measurement equations are deduced according to the network architecture. To solve the unavoidable estimation deviation of the mean and covariance of the states in the UKF algorithm, iterative computation is introduced into the UKF after the measurement update. While the measure- ment noise R is extended into the state vectors before iteration in order to meet the statistic orthogonality of estimate and mea- surement noise. The IUKF algorithm can provide the optimized estimation for the neural network because of its state expansion and iteration. Temperature rise (-20-20℃) and drop (70-20℃) tests for FOG are carried out in an attemperator. The temperature drift model is built with neural network, and it is trained respectively with BP, UKF and IUKF algorithms. The results prove that the proposed model has higher precision compared with the back- propagation (BP) and UKF network models. 展开更多
关键词 fiber optic gyro (FOG) temperature drift neural net- work iterated unscented Kalman filter (IUKF).
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Application of fiber Bragg grating sensor network in aluminum reduction tank shell temperature monitoring 被引量:5
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作者 姜明顺 隋青美 +2 位作者 苗飞 贾磊 彭蓬 《Journal of Central South University》 SCIE EI CAS 2013年第4期924-930,共7页
A fiber Bragg grating temperature sensor network was designed to implement the real-time health monitoring of the aluminum reduction cell. The heat transfer process was simulated using software ANSYS, and an on-line s... A fiber Bragg grating temperature sensor network was designed to implement the real-time health monitoring of the aluminum reduction cell. The heat transfer process was simulated using software ANSYS, and an on-line shell monitoring system was established based on optical sensing technology. According to aluminum reduction cell heat transfer theory, the 2D slice finite element model was developed. The relationship between shell temperature and cell status was discussed. Fiber Bragg grating (FBG) was chosen as the temperature sensor in light of its unique advantages. The accuracy of designed FBG temperature sensors exceeds 2 ~C, and good repeatability was exhibited. An interrogation system with 104 sensors based on VPG (volume phase grating) filter was established. Through the long-term monitoring on running state, the status of the aluminum reduction cell, including security and fatigue life could be acquired and estimated exactly. The obtained results provide the foundation for the production status monitoring and fault diagnosis. Long-term test results show good stability and repeatability which are compatible with electrolysis process. 展开更多
关键词 aluminum reduction cell fiber Bragg grating numerical simulation shell temperature production status
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Flux-measuring approach of high temperature metal liquid based on BP neural networks 被引量:1
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作者 胡燕瑜 桂卫华 李勇刚 《Journal of Central South University of Technology》 2003年第3期244-247,共4页
A soft-measuring approach is presented to measure the flux of liquid zinc with high temperature andcausticity. By constructing mathematical model based on neural networks, weighing the mass of liquid zinc, the fluxof ... A soft-measuring approach is presented to measure the flux of liquid zinc with high temperature andcausticity. By constructing mathematical model based on neural networks, weighing the mass of liquid zinc, the fluxof liquid zinc is acquired indirectly, the measuring on line and flux control are realized. Simulation results and indus-trial practice demonstrate that the relative error between the estimated flux value and practical measured flux value islower than 1.5%, meeting the need of industrial process. 展开更多
关键词 FLUX high temperature METAL LIQUID flux-measuring NEURAL netWORKS
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Development of magnetocaloric materials in room temperature magnetic refrigeration application in recent six years 被引量:2
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作者 刘敏 俞炳丰 《Journal of Central South University》 SCIE EI CAS 2009年第1期1-12,共12页
Some magnetocaloric materials were used successfully in magnetic refrigeration application and became one of the critical parts of magnetic refrigeration technology whose delightful progresses were made worldwide in t... Some magnetocaloric materials were used successfully in magnetic refrigeration application and became one of the critical parts of magnetic refrigeration technology whose delightful progresses were made worldwide in the past 30 years. At the same time, the research on giant magnetocaloric materials will accelerate the development of room temperature magnetic refrigeration. In this paper, the new theoretical and experimental investigations on magnetic materials in room temperature application were described, including Gd and its binary and ternary intermetallic compounds, Mn-based compounds, La(Fe13-xMx)-based compounds and manganites. Based on the analysis of hysteresis, corrosion, cost and heat process, the comparison between different families of magnetic materials was discussed. Further research of room temperature magnetic refrigerant was suggested. 展开更多
关键词 magnetic material REFRIGERATION magnetocaloric effect magnetic resistance
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Genetic variability predicting breeding potential of upland cotton(Gossypium hirsutum L.)for high temperature tolerance 被引量:2
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作者 FAROOQ Amjad SHAKEEL Amir +5 位作者 SAEED Asif FAROOQ Jehanzeb RIZWAN Muhammad CHATTHA Waqas Shafqat SARWAR Ghulam RAMZAN Yasir 《Journal of Cotton Research》 CAS 2023年第2期81-97,共17页
Background High temperature stress at peak flowering stage of cotton is a major hindrance for crop potential.This study aimed to increase genetic divergence regarding heat tolerance in newly developed cultivars and hy... Background High temperature stress at peak flowering stage of cotton is a major hindrance for crop potential.This study aimed to increase genetic divergence regarding heat tolerance in newly developed cultivars and hybrids.Fifty cotton genotypes and 40 F1(hybrids)were tested under field conditions following the treatments,viz.,high temperature stress and control at peak flowering stage in August and October under April and June sowing,respectively.Results The mean squares revealed significant differences among genotypes,treatments,genotype×treatment for relative cell injury,chlorophyll contents,canopy temperature,boll retention and seed cotton yield per plant.The genetic diversity among 50 genotypes was analyzed through cluster analysis and heat susceptibility index(HSI).The heat tolerant genotypes including FH-Noor,NIAB-545,FH-466,FH-Lalazar,FH-458,NIAB-878,IR-NIBGE-8,Weal-AGShahkar,and heat sensitive,i.e.,CIM-602,Silky-3,FH-326,SLH-12 and FH-442 were hybridized in line×tester fashion to produce F1 populations.The breeding materials’populations(40 F1)revealed higher specific combining ability variances along with dominance variances,decided the non-additive type gene action for all the traits.The best general combining ability effects for most of the traits were displayed by the lines,i.e.,FH-Lalazar,NIAB-878 along with testers FH-326 and Silky-3.Specific combining ability effects and better-parent heterosis were showed by the crosses,viz.,FH-Lalazar×Silky-3,FH-Lalazar×FH-326,NIAB-878×Silky-3,and NIAB-878×FH-326 for seed cotton yield and yield contributing traits under high temperature stress.Conclusion Heterosis breeding should be carried out in the presence of non-additive type gene action for all the studied traits.The best combiner parents with better-parent heterosis may be used in crossing program to develop high yielding cultivars,and hybrids for high temperature stress tolerance. 展开更多
关键词 High temperature Upland cotton Peak flowering HETEROSIS Gene action Combining ability
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Assessing target optical camouflage effects using brain functional networks:A feasibility study
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作者 Zhou Yu Li Xue +4 位作者 Weidong Xu Jun Liu Qi Jia Jianghua Hu Jidong Wu 《Defence Technology(防务技术)》 SCIE EI CAS CSCD 2024年第4期69-77,共9页
Brain functional networks model the brain's ability to exchange information across different regions,aiding in the understanding of the cognitive process of human visual attention during target searching,thereby c... Brain functional networks model the brain's ability to exchange information across different regions,aiding in the understanding of the cognitive process of human visual attention during target searching,thereby contributing to the advancement of camouflage evaluation.In this study,images with various camouflage effects were presented to observers to generate electroencephalography(EEG)signals,which were then used to construct a brain functional network.The topological parameters of the network were subsequently extracted and input into a machine learning model for training.The results indicate that most of the classifiers achieved accuracy rates exceeding 70%.Specifically,the Logistic algorithm achieved an accuracy of 81.67%.Therefore,it is possible to predict target camouflage effectiveness with high accuracy without the need to calculate discovery probability.The proposed method fully considers the aspects of human visual and cognitive processes,overcomes the subjectivity of human interpretation,and achieves stable and reliable accuracy. 展开更多
关键词 Camouflage effect evaluation Electroencephalography(EEG) Brain functional networks Machine learning
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Mission-oriented capability evaluation for combat network based on operation loops
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作者 Yang Wang Junyong Tao +2 位作者 Xiaoke Zhang Guanghan Bai Yunan Zhang 《Defence Technology(防务技术)》 SCIE EI CAS CSCD 2024年第12期156-175,共20页
With continuous growth in scale,topology complexity,mission phases,and mission diversity,challenges have been placed for efficient capability evaluation of modern combat systems.Aiming at the problems of insufficient ... With continuous growth in scale,topology complexity,mission phases,and mission diversity,challenges have been placed for efficient capability evaluation of modern combat systems.Aiming at the problems of insufficient mission consideration and single evaluation dimension in the existing evaluation approaches,this study proposes a mission-oriented capability evaluation method for combat systems based on operation loop.Firstly,a combat network model is given that takes into account the capability properties of combat nodes.Then,based on the transition matrix between combat nodes,an efficient algorithm for operation loop identification is proposed based on the Breadth-First Search.Given the mission-capability satisfaction of nodes,the effectiveness evaluation indexes for operation loops and combat network are proposed,followed by node importance measure.Through a case study of the combat scenario involving space-based support against surface ships under different strategies,the effectiveness of the proposed method is verified.The results indicated that the ROI-priority attack method has a notable impact on reducing the overall efficiency of the network,whereas the O-L betweenness-priority attack is more effective in obstructing the successful execution of enemy attack missions. 展开更多
关键词 Combat network Operation loop identification Mission-oriented network reliability network effectiveness evaluation Strike strategies
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Effect and mechanism of on-chip electrostatic discharge protection circuit under fast rising time electromagnetic pulse
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作者 Mao Xinyi Chai Changchun +3 位作者 Li Fuxing Lin Haodong Zhao Tianlong Yang Yintang 《强激光与粒子束》 CAS CSCD 北大核心 2024年第10期44-52,共9页
The electrostatic discharge(ESD)protection circuit widely exists in the input and output ports of CMOS digital circuits,and fast rising time electromagnetic pulse(FREMP)coupled into the device not only interacts with ... The electrostatic discharge(ESD)protection circuit widely exists in the input and output ports of CMOS digital circuits,and fast rising time electromagnetic pulse(FREMP)coupled into the device not only interacts with the CMOS circuit,but also acts on the protection circuit.This paper establishes a model of on-chip CMOS electrostatic discharge protection circuit and selects square pulse as the FREMP signals.Based on multiple physical parameter models,it depicts the distribution of the lattice temperature,current density,and electric field intensity inside the device.At the same time,this paper explores the changes of the internal devices in the circuit under the injection of fast rising time electromagnetic pulse and describes the relationship between the damage amplitude threshold and the pulse width.The results show that the ESD protection circuit has potential damage risk,and the injection of FREMP leads to irreversible heat loss inside the circuit.In addition,pulse signals with different attributes will change the damage threshold of the circuit.These results provide an important reference for further evaluation of the influence of electromagnetic environment on the chip,which is helpful to carry out the reliability enhancement research of ESD protection circuit. 展开更多
关键词 fast rising time electromagnetic pulse damage effect electrostatic discharge protection circuit damage location prediction
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Temperature influences of the recoil characteristics for aluminum honeycomb buffer in the tether-net launcher 被引量:1
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作者 Wen-hui Shi Shuai Yue +5 位作者 Chun-bo Wu Zhou Liu Zhi Liu Bei-bei Zhao Zhong-hua Du Guang-fa Gao 《Defence Technology(防务技术)》 SCIE EI CAS CSCD 2023年第11期39-54,共16页
Fluctuations in outer space's temperature would affect the spacecraft's regular operation.This paper aims to study the temperature influences of the aluminum honeycomb buffer in the tether-net launcher.Firstly... Fluctuations in outer space's temperature would affect the spacecraft's regular operation.This paper aims to study the temperature influences of the aluminum honeycomb buffer in the tether-net launcher.Firstly,a buffer structure was designed to attenuate the pyroshock generated by the pyrotechnic device.Secondly,the mechanical properties of aluminum honeycomb at different temperatures were obtained through quasi-static compression experiments.Then,the internal ballistic responses of the launcher were gained by the closed bomb tests and the equivalent classical interior ballistic model.Finally,the recoil performance of the launcher with aluminum honeycomb buffer at different temperatures was studied.It is revealed that the aluminum honeycomb crushing force gradually decreases with the temperature increases.The peak pressure,burning rate coefficient and velocity increase while the peak time decreases with the temperature increase for the interior ballistics.For the launcher recoil responses,the average launch recoil decreases if the aluminum honeycomb doesn't enter the dense stage.The impact acceleration,projectile velocity and displacement increase as the temperature increase.The paper spotlights the temperature's influence on the recoil characteristics of the aluminum honeycomb buffer,which provides a new idea for buffering technology of pyrotechnic devices in a complex space environment. 展开更多
关键词 Tether-net launcher temperature Aluminum honeycomb buffer Interior ballistic responses Launch recoil characteristics
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ADC-GERT network parameter estimation model for mission effectiveness of joint operation system 被引量:6
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作者 FANG Zhigeng WU Shuang +1 位作者 ZHANG Xiaoli SUN Yunke 《Journal of Systems Engineering and Electronics》 SCIE EI CSCD 2021年第6期1394-1406,共13页
Effectiveness evaluation of the joint operation system is an important basis for the demonstration and development of weapon equipment.With the consideration that existing models of system effectiveness evaluation sel... Effectiveness evaluation of the joint operation system is an important basis for the demonstration and development of weapon equipment.With the consideration that existing models of system effectiveness evaluation seldom describe the structural relationship among equipment clearly as well as reflect the dynamic,the analog-to-digital converter-graphical evaluation and review technique(ADC-GERT)network parameter estimation model is proposed based on the ADC model and the joint operation system structure.Firstly,analysis of the joint operation system structure and operation process is conducted to build the GERT network,where equipment subsystems are nodes and activities are directed arches.Then the mission effectiveness of equipment subsystems is calculated by the ADC model.The probability transfer parameters are modified by the mission effectiveness of equipment subsystems based on the Bayesian theorem,with the ADC-GERT network parameter estimation model constructed.Finally,a case study is used to validate the efficiency and dynamic of the ADC-GERT network parameter estimation model. 展开更多
关键词 joint operation system system mission effectiveness analog-to-digital converter(ADC)model graphical evaluation and review technique(GERT) parameter estimation
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