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High-accuracy calibration for multi-laser powder bed fusion via in situ detection and parameter identification

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Advances in Manufacturing 2022年第4期10卷 556-570页

作者： Qi Zhong xiao-yong tian xiao-Kang Huang Zhi-Qiang Tong Yi Cao Di-Chen Li State Key Laboratory of Manufacturing Systems Engineering Xi’an Jiaotong UniversityXi’an710049People’s Republic of China

Multi-laser powder bed fusion(ML-PBF)adopts multiple laser-scanner systems to increase the build envelope and build speed,but its calibration is an iterative and time-consuming *** particular,multiple large-scale scan fields have a complex distortion in the overlap area,challenging the calibration *** this study,owing to the enormous workload and alignment problems in the calibration of multiple scan fields,a novel calibration system is designed in this study to realize in situ auto-detection of numerous laser spots in the build chamber to ensure high efficiency and ***,because the detectable area could not cover the entire build area and the detection data still contained errors,a virtual laser-scanner system was established by identifying the assembly defects and galvo nonlinearities of the ML-PBF system from the detection data,which served as the system's controller to improve calibration *** multi-field alignment error was less than 0.012%,which could avoid the intersection and separation of scan paths in multi-laser scanning and therefore meet the requirements for high-precision ***,the reliability of the method was verified theoretically using principal component analysis.

关键词： Powder bed fusion Multi-laser technology Galvo calibration Assembly defects System identification

Real-time process control of powder bed fusion by monitoring dynamic temperature field

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Advances in Manufacturing 2020年第3期8卷 380-391页

作者： xiao-Kang Huang xiao-yong tian Qi Zhong Shun-Wen He Chun-Bao Huo Yi Cao Zhi-Qiang Tong Di-Chen Li State Key Laboratory of Manufacturing Systems Engineering Xi’an Jiaotong UniversityXi’an710049People’s Republic of China

This study aims to optimize the uniformity of the temperature field during sintering to improve part performance.A temperature-field monitoring system is established based on an infrared thermal imager and the temperature field data obtained during the sintering of a part can be measured in real *** relationship among the sintering temperature field,sintering process parameters,and part performance is established ***,a temperature field monitoring and analysis system is constructed,and various sintering temperature-field control strategies are established for various part ***,a dynamic control strategy for controlling the temperature field during sintering is proposed,experimentally validated,and fully integrated into a developed powder bed fusion(PBF)*** eight-shaped standard parts,the range of sintering temperature field is optimized from 44.1℃to 19.7℃,whereas the tensile strength of the parts increased by 15.4%.For large-size H parts,localized over burning is eliminated and the final quality of the part is *** strategy is critical for the optimization of the PBF process for large-sized parts,in particular in the large-sized die manufacturing industry,which offers promise in the optimization of part performance.

关键词： Powder bed fusion(PBF) Sintering temperature field Monitoring system Infrared thermal imager

Calculation Method of Optimal Speed Profile for Hot Plate During Controlled Cooling Process

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Journal of Iron and Steel Research International 2011年第5期18卷 38-41页

作者： WANG Bing-xing CHEN xiao-lin tian yong WANG Zhao-dong WANG Jun ZHANG Dian-hua State Key Laboratory of Rolling and Automation Northeastern UniversityShenyang 110004LiaoningChina

The healthy and rapid development of the controlled cooling technology was hampered by the uneven cooling phenomenon. During the process of hot plate production,the homogeneous cooling along the length direction of plate was constrained by lots of factors. And because the speed was a flexible control parameter,the calculation method of optimal speed profile was developed based on the measured start cooling temperature and its matrix equation was solved by the Cholesky decomposition method. The optimal speed profile was used in online control system. As a result,the temperature distribution along the plate length direction was relatively uniform,and 95% of measured final cooling temperature difference from the target temperature 700 ℃ was controlled within ±20 ℃.

关键词： plate controlled cooling homogeneous cooling speed profile Cholesky decomposition method

Simulation Model for Photosynthetic Production in Oilseed Rape

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Pedosphere 2009年第6期19卷 700-710页

作者： TANG Liang, ZHU Yan 2 , LIU xiao-Jun, tian yong-Chao, YAO Xia and CAO Wei-Xing Jiangsu Key Laboratory for Information Agriculture, Nanjing Agricultural University, Nanjing 210095 (China) Jiangsu Key Laboratory for Information Agriculture Nanjing Agricultural University Nanjing 210095 (China)

Photosynthetic production is a major determinant of final yield in crop plants. A simulation model was developed for canopy photosynthesis and dry matter accumulation in oilseed rape (Brassica napus L.) based on the ecophysiological processes and using a three-layer radiation balance scheme for calculating the radiation interception and absorption by the layers of flowers, pods, and leaves within the canopy. Gaussian integration method was used to calculate photosynthesis of the pod and leaf layers, and the daily total canopy photosynthesis was determined by the sum of photosynthesis from the two layers of green organs. The effects of physiological age, temperature, nitrogen, and water deficit on maximum photosynthetic rate were quantified. Maintenance and growth respiration were estimated to determine net photosynthetic production. Partition index of the shoot in relation to physiological development time was used to calculate shoot dry matter from plant biomass and shoot biomass loss because of freezing was quantified by temperature effectiveness. Testing of the model for dynamic dry matter accumulation through field experiments of different genotypes, sowing dates, and nitrogen levels showed good fit between the observed and simulated data, with an average root mean square error of 10.9% for shoot dry matter. Thus, the present model appears to be reliable for the prediction of photosynthetic production in oilseed rape.

关键词： canopy CO2 assimilation dry matter accumulation N nutrition index radiation

社会资本影响农村生态环境治理的机制与对策分析

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理论探讨 2018年第1期 113-119页

作者：肖永添北京师范大学(珠海)特许经营学院广东珠海519085

在对社会资本影响农村生态环境治理的机制进行分析的基础上,探讨了政府治理机制与社会资本治理机制之间的关系,并提出相应的对策建议。研究发现我国农村地区的社会资本具有如下特性:关系网络的封闭性和同质性;规范的非正式性和道德声誉... 详细信息

在对社会资本影响农村生态环境治理的机制进行分析的基础上,探讨了政府治理机制与社会资本治理机制之间的关系,并提出相应的对策建议。研究发现我国农村地区的社会资本具有如下特性:关系网络的封闭性和同质性;规范的非正式性和道德声誉的重要性;信任的人际性和信任半径的有限性。这三个特征导致社会资本治理机制并不必然带来农村生态环境的治理和保护,但是其在小范围生态环境治理方面的效率要远远高于其在大范围生态环境治理方面的效率。同时,无论是目前主导的政府治理机制还是社会资本治理机制,都存在其自身的局限性,但是这两种治理机制之间并不是矛盾的。社会资本机制可以有效提高政府机制的治理能力,同时拓宽污染关系人的参与渠道;政府机制则可以解决大范围农村生态环境的治理问题,同时在一定程度上缓解社会资本机制所不能应对的新型生态环境治理问题。所以,社会资本机制和政府机制中的治理方式可以相互补充,共同发挥作用,促进农村生态环境的改善。

关键词：社会资本农村生态环境政府治理机制

The Hilbert expansion of the Boltzmann equation in the incompressible Euler level in a channel

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Science China Mathematics 2025年第1期68卷 39-88页

作者： Feimin Huang Weiqiang Wang yong Wang Feng xiao Academy of Mathematics and Systems Science Chinese Academy of Sciences School of Mathematical Sciences University of Chinese Academy of Sciences Key Laboratory of Computing and Stochastic Mathematics (Ministry of Education) School of Mathematics and StatisticsHunan Normal University

The study of the hydrodynamic limit of the Boltzmann equation with physical boundary is a challenging problem due to the appearance of the viscous and Knudsen boundary *** this paper,the hydrodynamic limit from the Boltzmann equation with the specular reflection boundary condition to the incompressible Euler equations in a channel is *** on the multi-scaled Hilbert expansion,the equations with boundary conditions and compatibility conditions for interior solutions,and viscous and Knudsen boundary layers are derived under different scaling,***,some uniform estimates for the interior solutions,and viscous and Knudsen boundary layers are *** the help of the L2-L∞framework and the uniform estimates obtained above,the solutions to the Boltzmann equation are constructed by the truncated Hilbert expansion with multiscales,and hence the hydrodynamic limit in the incompressible Euler level is justified.

关键词： Boltzmann equation incompressible Euler equations hydrodynamic limit Hilbert expansion specular reflection boundary condition viscous boundary layer Knudsen boundary layer

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基于AMBA总线接口的以太网IP核

计算机工程 2007年第22期33卷 252-254,257页

作者：刘虎肖永田章军中国科学院计算技术研究所北京100083

介绍了一款32位SoC芯片中基于AMBA AHB总线接口的以太网IP核的设计。目前该IP核已通过RTL级测试与FPGA验证。通过性能测试,表明该以太网IP核能满足许多实际应用的需求。由于其具有标准的总线接口,因此完全可以作为一个可重用的IP核。

关键词：以太网控制器 SoC AMBA IP核

Separation of the ionospheric and thermospheric contributions in the data from the Triple Ionosophere Photo Meter onboard the Feng-Yun 3E satellite

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Science China Earth Sciences 2025年第1期68卷 172-184页

作者： Fang JIANG tian MAO Jin-Song WANG Xiu-Qing HU xiao-Xin ZHANG Liping FU Nan JIA tianfang WANG National Space Science Center Chinese Academy of Sciences Beijing Key Laboratory of Space Environment Exploration Key Laboratory of Environmental Space Situation Awareness Technology National Satellite Meteorological Center China Meteorological Administration

The Triple Ionosphere Photo Meter （TRIPM） is a far ultraviolet nadir-view photometer that is onboard the secondgeneration,polar-orbiting Chinese meteorological satellite Feng-Yun 3E （FY-3E）,which was launched on July 5,*** has three channels,and each is used to measure different types of emissions:（1） 135.6 nm airglow produced by the recombination of the O+ions and electrons in the absence of sunlight （nighttime channel）;（2） 135.6 nm airglow from the OI when sunlight is present （daytime/dusk-dawn 135.6 nm channel）;and （3） Airglow in the N2LBH of the TRIPM （daytime/dusk-dawn N2LBH channel）.FY-3E is a satellite operating in the early morning ***,the data are mostly distributed on the dawndusk side or at times when the solar zenith angle is relatively *** this study,combined with simulation calculations,the data are *** further explore the application value of the data products,a model is used to separate the ionospheric radiative recombination contribution from the thermosphere photoelectron impact excitation contribution in the data from the daytime/dusk-dawn 135.6 nm *** approach not only improves the accuracy of O/N2derived from the 135.6 nm channel and N2LBH channel but also provides the ionospheric 135.6 nm radiance at the same time as the *** results show that the 135.6 nm radiance originating from the combination of O+and electrons extracted from the measurement data exhibits similar equatorial anomaly peak structure characteristics and seasonal variations as the corresponding GPS total electron content （TEC） *** the other hand,the separated 135.6 nm radiance generated from the thermosphere photoelectron collision excitation does not contain radiative recombination contributions;thus,the ionosphere influence is greatly avoided when the O/N2is obtained.

关键词： Far ultraviolet 135.6 nm emission intensity Photoelectron impact excitation Radiative recombination excitation

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Enhancing m^(6)A modification in the motor cortex facilitates corticospinal tract remodeling after spinal cord injury

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Neural Regeneration Research 2025年第6期20卷 1749-1763页

作者： tian Qin Yuxin Jin Yiming Qin Feifei Yuan Hongbin Lu Jianzhong Hu yong Cao Chengjun Li Department of Spine Surgery and Orthopedics Xiangya HospitalCentral South UniversityChangshaHunan ProvinceChina Key Laboratory of Organ Injury Aging and Regenerative Medicine of Hunan ProvinceChangshaHunan ProvinceChina National Clinical Research Center for Geriatric Disorders Xiangya HospitalCentral South UniversityChangshaHunan ProvinceChina Department of Sports Medicine Xiangya HospitalCentral South UniversityChangshaHunan ProvinceChina

Spinal cord injury typically causes corticospinal tract disruption. Although the disrupted corticospinal tract can self-regenerate to a certain degree, the underlying mechanism of this process is still unclear. N6-methyladenosine(m^(6)A) modifications are the most common form of epigenetic regulation at the RNA level and play an essential role in biological processes. However, whether m^(6)A modifications participate in corticospinal tract regeneration after spinal cord injury remains unknown. We found that expression of methyltransferase 14 protein(METTL14) in the locomotor cortex was high after spinal cord injury and accompanied by elevated m^(6)A levels. Knockdown of Mettl14 in the locomotor cortex was not favorable for corticospinal tract regeneration and neurological recovery after spinal cord injury. Through bioinformatics analysis and methylated RNA immunoprecipitation-quantitative polymerase chain reaction, we found that METTL14 regulated Trib2 expression in an m^(6)A-regulated manner, thereby activating the mitogen-activated protein kinase pathway and promoting corticospinal tract regeneration. Finally, we administered syringin, a stabilizer of METTL14, using molecular docking. Results confirmed that syringin can promote corticospinal tract regeneration and facilitate neurological recovery by stabilizing METTL14. Findings from this study reveal that m^(6)A modification is involved in the regulation of corticospinal tract regeneration after spinal cord injury.

关键词： corticospinal tract remodeling epigenetic regulations locomotor cortex m^(6)A modification methyltransferase 14 protein(METTL14) mitogen-activated protein kinase neural regeneration spinal cord injury syringin TRIB2