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基于注意力Seq2Seq模型的终端区航空器航迹预测

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科学技术与工程 2024年第9期24卷 3882-3895页

作者：卢婷婷刘博李纯柱中国民航大学空中交通管理学院天津300300 中国民用航空华北地区空中交通管理局天津分局天津300300

为充分挖掘机场终端区航空器航迹时间依赖性,解决中长期、多步长航迹预测精度不稳定的问题,引入注意力机制(attention mechanism)和教师监督(teacher forcing)中的指数衰减(exponential decay)采样方法,提出了一种基于序列到序列框架的... 详细信息

为充分挖掘机场终端区航空器航迹时间依赖性,解决中长期、多步长航迹预测精度不稳定的问题,引入注意力机制(attention mechanism)和教师监督(teacher forcing)中的指数衰减(exponential decay)采样方法,提出了一种基于序列到序列框架的机场终端区航迹预测模型(Seq2Seq-attention mechanism-exponential decay,SAE)。序列到序列框架实现了多步长预测,注意力机制提高解码器预测精度,指数衰减采样方法加速了训练阶段模型收敛,在一定程度上提高了模型的泛化性。最后,为了验证提出方法的有效性,利用天津终端区28架次、90 d ADS-B航迹数据构建原始数据集,以平均绝对误差(mean squared error,MAE)和均方根误差(root mean squared error,RMSE)作为模型性能评价指标,进行了航迹预测实验,实验结果表明:高度、经度和纬度在序列到序列框架中的循环神经网络分别采用LSTM、GRU和LSTM可以获得最好预测性能;以4种预测长度1、3、5和10 min进行建模,与基线模型中预测性能最好的结果比较,所提出方法在验证集上的高度、经度和纬度指标表现最优,10 min预测窗口下的平均绝对误差分别降低了66.30%、54.62%和36.59%,均方根误差分别降低了65.45%、38.16%和20.57%,同时,上述4种预测时长下所提出方法预测结果的均值和方差最小,表明随着预测时长的增加,模型预测结果的稳定性最好。此外,引入的注意力机制与指数衰减采样方法对有效捕捉航迹时间依赖性、提高模型泛化性均具有积极的贡献。

关键词：航空运输航迹预测终端区序列到序列框架注意力机制

Effect of magnetic field on elements segregation in electroslag ingot

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Journal of Iron and Steel Research International 2022年第3期29卷 434-444页

作者： Gang Gao chun-li zhu Xiao-fang Shi li-zhong Chang School of Metallurgy Engineering Anhui University of TechnologyMa’anshan243002AnhuiChina SINO STEEL Ma’anshan Institute of Mining Research Co. Ltd.Ma’anshan243000AnhuiChina

In order to improve the production efficiency of electroslag remelting process and the solidification quality of electroslag ingot,a novel electroslag furnace with electromagnetic stirring was designed and the effects of external magnetic field and different electrical parameters on electroslag remelting process were *** distribution of carbon,chromium,phosphorus and compactness in electroslag ingot was analyzed through original position analysis *** show that the external magnetic field accelerates the remelting of consumable *** the condition of remelting voltage of 34 V and current of 1500 A,the remelting rate of metal consumable electrode increases from 20 to 27 mm min−1 when the magnetic induction intensity of 62×10^(−4) and 108×10^(−4) T is ***,the remelting current decreases from 1500 to 1100 A under the condition of constant remelting rate and remelting voltage,thereby reducing the energy *** effect of external magnetic field on the segregation of different elements in electroslag ingot is *** the experimental conditions,the carbon segregation is unremarkable,but the phosphorus segregation is improved when the electromagnetic force generated by the interaction between the external magnetic field and the remelting current is ***,the excessive electromagnetic force aggravates the segregation of carbon and *** the increase in electromagnetic force,the chromium segregation gradually increases.

关键词： Electroslag remelting Magnetic field Solidification Segregation Remelting rate

Recognition of FAST reflector nodes based on Canny operator

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Research in Astronomy and Astrophysics 2020年第8期20卷 230-236页

作者： Wei Tang li-chun zhu Qi-Ming Wang National Astronomical Observatories Chinese Academy of SciencesBeijing 100101China Key Laboratory of Radio Astronomy Beijing 100101China University of Chinese Academy of Sciences Beijing 100049China

The reflector system of Five-hundred-meter Aperture Spherical radio Telescope(FAST)is designed as 4450 rigid panels a flexible cable-net *** use 10 total stations to measure2225 nodes of the cable-net and then control the shape of the *** time,it takes at least 35 minutes to finish the calibration of the whole cable-net *** is indeed far too ***,we developed a set of highly efficient instrument CRRS(CCD Rotation Ranging System).It is based on photogrammetry and can finish the measurement in 1 ***,the target we used in CRRS is active target,and it has serious electromagnetic interference problems to affect the use of *** the above reasons into consideration,we plan to identify the nodes by taking the gap between the reflector panels as the feature *** new method can take the place of active targets to finish the measuring *** present work focuses on the following ***,combined with the characteristics of FAST reflector images,the representative algorithms of image edge detection are ***,the process of node extraction is introduced in detail so that we know that it *** addition,experimental results are given to draw a conclusion so that Canny algorithm was used for continuous research of reflector edge detection.

关键词： telescopes Astronomical Instrumentation Methods and Techniques methods:data analysis

Differential correction method applied to measurement of the FAST reflector

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Research in Astronomy and Astrophysics 2016年第8期16卷 25-32页

作者： Xin-Yi li li-chun zhu Jin-Wen Hu Zhi-Heng li National Astronomical Observatories Chinese Academy of Sciences Beijing 100012 China University of Chinese Academy of Sciences Beijing 100049 China

The Five-hundred-meter Aperture Spherical radio Telescope （FAST） adopts an active deformable main reflector which is composed of 4450 triangular panels. During an observation, the illuminated area of the reflector is deformed into a 300-m diameter paraboloid and directed toward a source. To achieve accurate control of the reflector shape, positions of 2226 nodes distributed around the entire reflector must be measured with sufficient precision within a limited time, which is a challenging task because of the large scale. Measurement of the FAST reflector makes use of stations and node targets. However, in this case the effect of the atmosphere on measurement accuracy is a significant issue. This paper investigates a differen- tial correction method for total stations measurement of the FAST reflector. A multi-benchmark differential correction method, including a scheme for benchmark selection and weight assignment, is proposed. On- site evaluation experiments show there is an improvement of 70%-80% in measurement accuracy compared with the uncorrected measurement, verifying the effectiveness of the proposed method.

关键词： telescopes -- FAST -- measurement -- differential correction

Unit panel node detection by CNN on FAST reflector

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Research in Astronomy and Astrophysics 2019年第1期19卷 113-122页

作者： Zhi-Song Zhang li-chun zhu Wei Tang Xin-Yi li National Astronomical Observatories Chinese Academy of Sciences University of Chinese Academy of Sciences

The Five-hundred-meter Aperture Spherical radio Telescope(FAST) has an active *** observations, the reflector will be deformed into a paraboloid 300 meters in diameter. To improve its surface accuracy, we propose a scheme for photogrammetry to measure the positions of 2226 nodes on the reflector. The way to detect the nodes in the photos is the key problem in this application of photogrammetry. This paper applies a convolutional neural network(CNN) with candidate regions to detect the nodes in the photos. Experimental results show a high recognition rate of 91.5%, which is much higher than the recognition rate for traditional edge detection.

关键词： telescopes FAST photogrammetry nodes detect convolutional neural network

Transformation of chlorine in NaCl-loaded Victorian brown coal during the gasification in steam

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燃料化学学报 2012年第12期40卷 1409-1414页

作者： ZHANG Shu Mohammad Asadullah Rosalie Hocking liN Jian-ying li chun-zhu Department of Chemical Engineering Monash University Fuels and Energy Technology Institute Curtin University of Technology Chemical Engineering Universiti Teknologi MARA Monash Centre for Synchrotron Science and School of Chemistry Monash University College of Chemistry and Chemical Engineering Taiyuan University of Technology

This study is to examine the changes in Cl volatilizations and chemical forms in NaCl-loaded Victorian brown coal during gasification in steam at 800 ℃ using Cl K-edge X-ray absorption near-edge structure(XANES) *** char samples were prepared in a novel one-stage fluidised-bed / fixed-bed quartz reactor at a fast heating *** samples were then collected and sealed in an argon-filled bag in order to minimise possible oxidation of char and Cl by air prior to analysis by ***-steam reactions were found to significantly affect the transformation of Cl,including the possible formation of chlorine-containing organic *** the other hand,volatile-char interactions during the gasification appeared to enhance the Cl retention and prevent the formation of organic chlorine compounds in chars.

关键词：气化理论燃料化学研究发展

Influence of coal blending on mineral transformation at high temperatures

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Mining Science and Technology 2009年第3期19卷 300-305页

作者： BAI Jin li Wen li chun-zhu BAI Zong-qing li Bao-qing State Key Laboratory of Coal Conversion Institute of Coal Chemistry Chinese Academy of Science Taiyuan Shanxi 030001 China Department of Chemical Engineering Monash University Monash Vic 3800 Australia

Transformation of mineral matter is important for coal utilization at high *** is especially true for blended *** and FTIR were employed together to study the transformation of mineral matter at high temperature in blended *** was found that the concentration of catalytic minerals, namely iron oxides, increases with an increasing ratio of Shenfu coal, which could improve coal *** transformation characteristics of the minerals in blended coals are not exactly predictable from the blend *** was proved by comparing the iron oxide content to the blending *** results from FTIR are comparable with those from *** is an effective method for examining variation in mineral matter.

关键词： coal blending high temperature mineral matter transformation

Cross-polymerization between the model furans and phenolics in bio-oil with acid or alkaline catalysts

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Green Energy & Environment 2021年第1期6卷 138-149页

作者： Qing Xu Xun Hu lijun Zhang Kai Sun Yuewen Shao Zhiran Gao Qing liu chun-zhu li School of Material Science and Engineering University of JinanJinan250022China Key Laboratory of Low Carbon Energy and Chemical Engineering College of Chemical and Environmental EngineeringShandong University of Science and TechnologyQingdao266590China Fuels and Energy Technology Institute Curtin UniversityGPO Box U1987PerthW16845Australia

Polymerization is a major challenge for the upgrading of bio-oil to biofuels,but is preferable for the production of carbon material from *** the mechanism for polymerization is of importance for tailoring property of carbon *** study investigated the characteristics for the polymerisation of furfural,vanillin,their cross-polymerization and the impacts of catalysts on their *** results indicated that the organic acids like acetic acid and formic acid could catalyze the polymerisation of furfural,while H_(2)SO_(4)or NaOH as catalyst could drastically enhance the degree of polymerization of *** showed a higher tendency towards polymerization than furfural and H_(2)SO_(4)or NaOH significantly facilitated the polymerization of vanillin via shifting the pasty product to solid *** crosspolymerization between furfural and vanillin occurred even in the absence of catalyst,while the presence of H_(2)SO_(4)or NaOH catalyst resulted in the formation of more solid polymer via *** polymerisation reactions were accompanied with the consumption of–C¼O via aldol addition/condensation *** addition,the morphology and thermal stability of the polymers formed were affected by both the type of the catalysts employed,which can in turn enhance the cross-polymerization between furfural and vanillin.

关键词： Furfural Vanillin Cross-polymerization Catalysts Polymers

不同煤阶热解半焦的FT-Raman光谱研究(英文)

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燃料化学学报 2005年第4期33卷 385-390页

作者： Xiao-jiang li chun-zhu li CRC for Clean Power from lignite Department of Chemical Engineering PO Box 36 Monash University Victoria 3800 Australia

在热天平上采用慢速升温制备了褐煤、高挥发分烟煤和低挥发分烟煤的半焦。采用FTRaman光谱对半焦进行了分析。半焦800cm-1至1800cm-1的Raman光谱可分解为10个谱带,以表征高度无序炭材料中的典型结构。光谱和谱带的强度比都可用来描述半... 详细信息

在热天平上采用慢速升温制备了褐煤、高挥发分烟煤和低挥发分烟煤的半焦。采用FTRaman光谱对半焦进行了分析。半焦800cm-1至1800cm-1的Raman光谱可分解为10个谱带,以表征高度无序炭材料中的典型结构。光谱和谱带的强度比都可用来描述半焦的结构特征。在600℃低温热解时,三种煤半焦的结构差异明显。随热解温度升至800℃或900℃,这种差别消失。褐煤中可交换的钠离子影响热解过程中的成焦反应。

关键词：半焦 Raman光谱热解煤煤阶