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星载光子计数激光测距雷达的实时去噪方法

红外与毫米波学报 2024年第2期43卷 242-253页

作者：谭崇涛于文博向雨琰李少辉余婧王倩莹李松武汉大学电子信息学院湖北武汉430072 中国空间技术研究院北京100098 武汉量子技术研究院湖北武汉430010

星载光子计数体制激光测距雷达系统具有高重频、高精度等显著优势,但也面临原始数据量大且噪声数据占比过高的问题。为适应星上数据通道的传输能力,需压缩原始数据量并保障信号光子的查全率,因此必须发展以硬件为主体的实时去噪算法。... 详细信息

星载光子计数体制激光测距雷达系统具有高重频、高精度等显著优势,但也面临原始数据量大且噪声数据占比过高的问题。为适应星上数据通道的传输能力,需压缩原始数据量并保障信号光子的查全率,因此必须发展以硬件为主体的实时去噪算法。本文提出一种粗精结合的快速去噪算法,首先基于激光器发射脉宽、系统噪声率、目标特性以及接收光子事件的局部密度信息进行粗去噪,剔除部分噪声光子;再利用直方图统计,对保留的光子事件进行精去噪,确定信号光子区间及最终的信号光子及其时间信息。通过蒙特卡洛仿真和ICESat-2实测数据对算法进行验证,测试结果表明,本算法查全率大于94%、查准率大于93%、调和平均值大于94%,运行效率提高了10%。算法可以实现光子事件的快速实时去噪,为星上硬件实时去噪处理提供了理论基础。

关键词：光子计数激光测距粗精去噪数据密度直方图统计

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一种新型先导式安全阀的设计

阀门 2024年第7期 846-855页

作者：胡锐朱崇涛何海涛赵承卓罗庶航天科工火箭技术有限公司湖北武汉430040

用于液体火箭动力系统的传统先导式安全阀一般由弹簧膜片式指挥阀和主阀组成,是一种全自动式被动泄压安全阀。本文根据安全阀的工作原理,将原弹簧膜片式指挥阀改为两位三通电磁阀,结合贮箱压力传感器,设计了一种主动泄压式的新型先导式... 详细信息

用于液体火箭动力系统的传统先导式安全阀一般由弹簧膜片式指挥阀和主阀组成,是一种全自动式被动泄压安全阀。本文根据安全阀的工作原理,将原弹簧膜片式指挥阀改为两位三通电磁阀,结合贮箱压力传感器,设计了一种主动泄压式的新型先导式安全阀。本文主要介绍了新型安全阀的工作原理和特性,针对新型安全阀的关键参数进行设计计算和仿真,生产出了符合动力系统要求的安全阀;并对实物产品进行试验验证,试验结果表明新型安全阀具有更小的启闭压差。

关键词：主动泄压安全阀两位三通电磁阀工作原理计算试验

Artificial Neural Network to Predict Leaf Population Chlorophyll Content from Cotton Plant Images

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Agricultural Sciences in China 2010年第1期9卷 38-45页

作者： SUO Xing-mei JIANG Ying-tao YANG Mei LI Shao-kun WANG Ke-ru WANG chong-tao College of Information Engineering Minzu University of China Beijing 100081 P.R.China Department of Electrical and Computer Engineering University of Nevada Las Vegas NV 89154 U.S.A Institute of Crop Sciences Chinese Academy of Agricultural Sciences Beijing 100081 P.R.China

Leaf population chlorophyll content in a population of crops, if obtained in a timely manner, served as a key indicator for growth management and diseases diagnosis. In this paper, a three-layer multilayer perceptron （MLP） artificial neural network （ANN） based prediction system was presented for predicting the leaf population chlorophyll content from the cotton plant images. As the training of this prediction system relied heavily on how well those leaf green pixels were separated from background noises in cotton plant images, a global thresholding algorithm and an omnidirectional scan noise filtering coupled with the hue histogram statistic method were designed for leaf green pixel extraction. With the obtained leaf green pixels, the system training was carried out by applying a back propagation algorithm. The proposed system was tested to predict the chlorophyll content from the cotton plant images. The results using the proposed system were in sound agreement with those obtained by the destructive method. The average prediction relative error for the chlorophyll density （μg cm^-2） in the 17 testing images was 8.41%.

关键词： artificial neural network image processing cotton plant leaf population chlorophyll content prediction

In-situ observation on the deformation behaviors of Fe-Mn-C TWIP steel

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International Journal of Minerals,Metallurgy and Materials 2009年第6期16卷 646-649页

作者： Zhen-li Mi Di Tang Yong-juan Dai Hai-tao Jiang Jian-chong Lu National Engineering Research Center for Advanced Rolling Technology University of Science and Technology Beijing Beijing 100083 China

The microstructure and crack behaviour of twinning induced plasticity （TWIP） steel during tensile deformation was investigated with in-situ scanning electron microscopy （SEM）. The results show that there are two modes of plastic deformation during tensile test in the Fe-Mn-C TWIP steel： dislocation gliding and deformation twins. During the process of tensile deformation, secondary deformed twins are found. Inclusions have played a role in the course of ductile fracture, and microcracks initiate from inclusions and twin-twin intersections.

关键词： TWIP steel in-situ observation deformation microstructure twinning induced plasticity

Effects of Chronic Stress and Phenytoin on the Long-term Potentiation (LTP) in Rat Hippocampal CA1 Region

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Acta Biochimica et Biophysica Sinica 2004年第5期36卷 375-378页

作者： Hui ZHENG*, Quan YANG, and chong-tao XU Mental Health Center, Shantou University Medical College, Shantou 515063, China Mental Health Center Shantou University Medical College Shantou 515063 China

To investigate the changes of LTP in hippocampal CA1 region induced by chronic stress and the effect of phenytoin on them, thirty-two adult male Sprague-Dawley rats were randomly divided equally into four groups: control group, control-phenytoin group, stress-saline group and stress-phenytoin group. Isolated hippocampal slices of rats were used to observe the changes of long-term potentiation (LTP) in hippocampal CA1 field using electrophysiological technique. Amplitude of population spike (PS) and field excitatory postsynaptic potentials (fEPSPs) slope were used to indicate the changes of LTP. High-frequency stimulation (HFS) was applied to Schaffer collaterals of hippocampal CA3 field, and the changes of PS amplitude and fEPSPs slope in CA1 field were observed. The results showed that the LTP induction rate, the increases of PS amplitude and fEPSPs slope after HFS in control and stress-phenytoin groups were significantly greater than those in stress-saline group (P0.05). It is suggested that chronic stress can damage the development of LTP in hippocampal CA1 field, while phenytoin can protect the LTP of stressed hippocampal slices in normal state.

关键词： phenytoin long-term potentiation hippocampus stress

Damage characteristics of YAG transparent ceramics under different loading conditions

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Defence Technology（防务技术） 2022年第8期18卷 1394-1404页

作者： Kuo Bao Xian-feng Zhang Gui-ji Wang Jia-jie Deng tao chong Dan Han Bing-qiang Luo Meng-ting Tan School of Mechanical Engineering Nanjing University of Science&TechnologyNanjing210094China Institute of Fluid Physics CAEPMianyang621900China Shanghai Institute of Ceramics Chinese Academy of SciencesShanghai200050China

YAG (Y_(3)Al_(5)O_(12)) transparent ceramics have attractive application prospects for transparent armor protection modules because of their excellent light transmittance and anti-ballistic capability. Understanding the fracture behavior and damage mechanism of YAG is necessary for armor design. To explore the damage characteristics of YAG under compression and tension, shock compression and shockless spalling experiments with soft recovery technique are conducted. The spall strength of YAG is obtained and the recovered samples are observed by CT and SEM. It is shown that the macroscopic damage characteristic of YAG under compression is vertical split cracks with oblique fine cracks distributed in the entire sample, while that under tension is horizontal transgranular cracks concentrated near the main spall surface. The cracks generated by macroscopic compression, tension and shear stress extend in similar tensile form at the microscale. The proportion of transgranular fractures on spall surfaces is higher than that of cracks induced by macroscopic compression. Meanwhile, higher loading rate and longer loading duration increase the transgranular fracture percentage.

关键词： YAG transparent Ceramics Damage characteristics Impact loading Shock compression Spall strength

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附加式声学黑洞对悬臂板振动寿命影响研究

振动工程学报 2024年第10期37卷 1669-1678页

作者：邹宇琪朱沈延王超炎陶翀骢张超吴义鹏季宏丽裘进浩南京航空航天大学航空航天结构力学及控制全国重点实验室江苏南京210016 南京信息技术研究院江苏南京210016

结构在振动条件下的疲劳破坏对其自身的使用寿命以及使用者的人身安全均带来了隐患,目前对于解决结构振动疲劳有添加加强筋、敷设大量阻尼材料等方法,但往往效率较低,附加质量过大。为解决上述问题,提出将附加式声学黑洞(ABH)安装在结构... 详细信息

结构在振动条件下的疲劳破坏对其自身的使用寿命以及使用者的人身安全均带来了隐患,目前对于解决结构振动疲劳有添加加强筋、敷设大量阻尼材料等方法,但往往效率较低,附加质量过大。为解决上述问题,提出将附加式声学黑洞(ABH)安装在结构上,通过降低结构响应达到降低应力幅值,延长使用寿命的目的。以悬臂板为基准结构,利用有限元方法进行了稳态动力学分析。结果表明,在附加矩形声学黑洞(RABH)后,悬臂板缺口处的应力响应明显降低。通过应力实验以及疲劳实验,验证了附加RABH可以降低结构危险点处应力响应,并延长悬臂板结构的振动疲劳寿命。

关键词：声学黑洞悬臂板振动疲劳

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Facile molybdenum and aluminum recovery from spent hydrogenation catalyst

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Chinese Journal of Chemical Engineering 2024年第5期69卷 72-78页

作者： Zhenhui Lv Jianan Li Dong Xue tao Yang Gang Wang chong Peng State Key Laboratory of Fine Chemicals School of Chemical EngineeringDalian University of TechnologyDalian 116024China Dalian Research Institute of Petroleum and Petrochemicals SINOPECDalian 116041China

Industrial catalyst waste has emerged as a hazardous pollutant that requires safe and proper disposal after the unloading *** a valuable and sustainable strategy for its treatment is a significant challenge compared to traditional *** this study,we present a facile method for the recovery of molybdenum and aluminum contents from spent Mo-Ni/Al_(2)O_(3) hydrogenation catalysts through crystallization separation and ***,the recovered molybdenum and aluminum are utilized as active metals and carriers for the preparation of new *** properties were thoroughly analyzed and investigated using various characterization *** hydrogenation activity of these newly prepared catalysts was evaluated on a fixed-bed small-scale device and compared with a reference catalyst synthesized from commercial raw ***,the hydrogenation activity of the catalysts was further assessed by using the entire distillate oil of coal liquefaction as the raw oil,specifically focusing on denitrogenation and aromatic *** work not only offers an effective solution for recycling catalysts but also promotes sustainable development.

关键词： Waste treatment Alumina Hydrogenation Catalyst Crystallization Precipitation

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可调汽蚀管式调节阀的仿真与试验研究

阀门 2024年第8期 969-976页

作者：何海涛朱崇涛胡锐陈苗赵承卓罗庶胡兆华航天科工火箭技术有限公司湖北武汉430040

可调汽蚀管式调节阀采用汽蚀文氏管原理,能有效实现推进剂流量的大范围调节,是液体火箭发动机推力调节的关键部件。本文针对不同锥度的两种阀杆,通过仿真和试验对其调节性能进行了分析研究,获得了阀杆不同行程下的有效流通面积和相对压... 详细信息

可调汽蚀管式调节阀采用汽蚀文氏管原理,能有效实现推进剂流量的大范围调节,是液体火箭发动机推力调节的关键部件。本文针对不同锥度的两种阀杆,通过仿真和试验对其调节性能进行了分析研究,获得了阀杆不同行程下的有效流通面积和相对压力损失。结果表明:两种阀杆的仿真结果和试验数据吻合较好,均能满足流量线性调节的要求,阀杆B的流量可调范围更大,但在满足流量调节范围的要求下,阀杆A的调节精度会更高。两种阀杆的相对压力损失试验结果相差不大,但阀杆A仿真得到的相对压力损失更大。通过仿真结果和试验数据的对比,验证了仿真模型的正确性,为相关设计提供重要参考。

关键词：调节阀火箭发动机变推力汽蚀仿真与试验研究