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Acta Metallurgica Sinica(English Letters) 2022年第3期35卷 425-438页

作者： yujian wang Shuo Chu Zhijun wang Junjie Li Jincheng wang State Key Laboratory of Solidification Processing Northwestern Polytechnical UniversityXi'an 710072China

Electron beam additive manufacturing is an effective method for the fabrication of complex metallic *** rapid solidification,the characteristics of microsegregation within the interdendritic region are interesting and important for the subsequent phase transformation and final mechanical ***,in view of the microsecond lifetime and the small length scale of the molten pool,experimentally investigating microsegregation is challenging,even with electron probe *** this study,a multiphase-field model coupled with the real thermodynamic data of Ti6Al4V alloy was successfully developed and applied to simulate the rapid solidification of columnarβgrains via electron beam additive *** thermal gradient(G)and cooling rate(R)were obtained from a 3D powder-scale multiphysics simulation and provided as inputs to a multiphase-field *** eff ects of the electron beam process parameters and thermal conditions on the columnarβgrains were *** films and droplets were observed to have solute enrichment in the intercellular *** size of the liquid film increased at a lower scanning speed and energy *** the scanning speed and energy power refined the columnarβgrains and decreased the liquid film *** extent of microsegregation considerably increased at lower energy power,whereas the change in scanning speed had little eff ect on the *** results also indicate that solute vanadium results in significant solute trapping and microsegregation during the rapid solidification of the Ti6Al4V alloy.

关键词： Ti6Al4V alloy Microsegregation Electron beam additive manufacturing Multiphase-field model

A Facial Expression Recognition Method Integrating Uncertainty Estimation and Active Learning

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Computers, Materials & Continua 2024年第10期81卷 533-548页

作者： yujian wang Jianxun Zhang Renhao Sun School of Computer Science and Engineering Chongqing University of TechnologyChongqing400054China Data Space Research Institute of Hefei Comprehensive National Science Center Hefei230088China

The effectiveness of facial expression recognition(FER)algorithms hinges on the model’s quality and the availability of a substantial amount of labeled expression ***,labeling large datasets demands significant human,time,and financial *** active learning methods have mitigated the dependency on extensive labeled data,a cold-start problem persists in small to medium-sized expression recognition *** issue arises because the initial labeled data often fails to represent the full spectrum of facial expression *** paper introduces an active learning approach that integrates uncertainty estimation,aiming to improve the precision of facial expression recognition regardless of dataset scale *** method is divided into two primary ***,the model undergoes self-supervised pre-training using contrastive learning and uncertainty estimation to bolster its feature extraction ***,the model is fine-tuned using the prior knowledge obtained from the pre-training phase to significantly improve recognition *** the pretraining phase,the model employs contrastive learning to extract fundamental feature representations from the complete unlabeled *** features are then weighted through a self-attention mechanism with rank ***,data from the low-weighted set is relabeled to further refine the model’s feature extraction *** pre-trained model is then utilized in active learning to select and label information-rich samples more *** results demonstrate that the proposed method significantly outperforms existing approaches,achieving an improvement in recognition accuracy of 5.09%and 3.82%over the best existing active learning methods,Margin,and Least Confidence methods,respectively,and a 1.61%improvement compared to the conventional segmented active learning method.

关键词： Expression recognition active learning self-supervised learning uncertainty estimation

VIDEO OBJECT SEGMENTATION BY 2-D MESH-BASED MOTION ANALYSIS

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Journal of Electronics(China) 2007年第5期24卷 668-673页

作者： wang yujian Gao Jianpo Yang Hao Wu Zhenyang School of Information Science and Engineering Southeast University Nanjing 210096 China

Video object extraction is a key technology in content-based video coding.A novel video object extracting algorithm by two Dimensional (2-D) mesh-based motion analysis is proposed in this ***,a 2-D mesh fitting the original frame image is obtained via feature detection algorithm. Then,higher order statistics motion analysis is applied on the 2-D mesh representation to get an initial motion detection *** post-processing,the final segmenting mask is quickly *** hence the video object is effectively *** results show that the proposed algorithm combines the merits of mesh-based segmenting algorithms and pixel-based segmenting algorithms,and hereby achieves satisfactory subjective and objective performance while dramatically increasing the segmenting speed.

关键词： Video object extraction 2-D mesh Higher order statistics

Comprehensive performance improvement of a water hydraulic high-speed on/off valve for underwater hydraulic manipulators using a multi-objective optimization method

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Frontiers of Mechanical Engineering 2024年第6期19卷 33-52页

作者： Lingkang MENG Hao ZHANG Fengwei XU yujian wang Defa WU School of Mechanical Science and Engineering Huazhong University of Science and TechnologyWuhan 430074China China Ship Scientific Research Center Wuxi 214082China

In ocean exploration,underwater hydraulic manipulators(UHMs)driven by water hydraulics may become favored over oil-based systems because of their eco-friendliness and ability for continuous operation.A water hydraulic high-speed on/off valve(WHSV),with good sealing and fast response,may be used as a core control component of *** comprehensive performance of the WHSV needs to be improved to enhance the accuracy,continuity,and reliability of *** this study,the relationship between the negative voltage and the WHSV characteristics,including dynamic performance,power losses,and impact performance,is studied by finite element ***,a multi-objective optimization method is proposed to improve the comprehensive performance of the *** method integrates the optimal Latin hypercube sampling method,universal Kriging surrogate model,non-dominated sorting genetic algorithm II,and Technique for Order Preference by Similarity to Ideal Solution methods to optimize the equivalent amplitude and duration of the negative *** findings reveal that the closing time decreases with the increase in the equivalent amplitude and duration of the negative voltage,while the opposite is observed in the power losses and maximum impact equivalent stress of the valve *** results show a slight 3.3%increase in closing time of the WHSV but significant reductions in total power loss(9.8%),maximum impact equivalent stress(14.5%),and maximum total deformation(19.8%).This study provides a practical optimization approach for enhancing the comprehensive performance of the WHSV for improved UHM operation.

关键词： water hydraulic high-speed on/off valve dynamic response power loss impact characteristics multiobjective optimization underwater hydraulic manipulator

Analysis of Electromagnetic Environment Effect Using TDIE-FDTD-MNA Hybrid Algorithm

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高电压技术 2013年第10期39卷 2383-2391页

作者： QIN yujian wang Wei LIU Peiguo ZHOU Dongming College of Electronic Science and Engineering National University of Defense Technology Changsha 410073 China

It is important but difficult to analyze the electromagnetic environment effect(E3) in the designing of modern airborne,sea,space,and ground *** a hybrid algorithm of time domain integral equation,finite difference time domain and modified nodal analysis(TDIE-FDTD-MNA) is developed to analyze the E3 of complex systems with cables and nonlinear circuit *** plane wave time domain(PWTD) enhanced TDIE method is adopted to solve field *** higher order FDTD(2,4) is adopted to solve cable *** MNA is adopted to obtain the response of complex circuits(with nonlinear structures).Numerical examples demonstrate the effectiveness of the proposed algorithm.

关键词：电磁环境效应算法分析混合时域积分方程非线性结构时域有限差分调制解调器地面系统

Determination of 24 Allergens in Perfume with High Performance Liquid Chromatography Tandem Mass Spectrometry

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China Detergent & Cosmetics 2019年第1期4卷 40-46页

作者： wang yujian Liang Zhengang Fu Lingmei Dong Cunzhu Technology Center of Hainan Entry-Exit Inspection and Quarantine Bureau China China College of Environment and Plant Protection Hainan UniversityChina

A method of 24 allergens determination in cosmetics were established with high performance liquid chromatography tandem mass spectrometry. The targeted compounds were extracted with acetonitrile and determined with LC-MS/MS (MRM mode) with external method. The linearity between concentrations and peak area ratio was obtained from 1.0~5.0 mg/L. The limits of detection were 1.0 mg/L for the instrument and 5.0 mg/kg for the method respectively. The LOQ was 15.0 mg/L. The average recoveries of 24 allergens were between 85.9% and 110.0% at spiked levels of 5, 10 and 20 mg/kg with relative standard derivation (RSDs) of 5.5%~12.0%(n=10). The method could be used as a reliable means for simultaneous quantitative determination of allergens in cosmetics.

关键词： perfume allergens flavor high performance liquid chromatography tandem mass spectrometry

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细粒级钛精矿烧结试验研究

钢铁钒钛 2020年第4期41卷 24-29页

作者：王禹键攀钢集团研究院有限公司钒钛资源综合利用国家重点试验室四川攀枝花617000

针对钛精矿粒度细,电炉冶炼损耗高的问题,着重对细粒级钛精矿烧结造块工艺进行了试验探索与研究。细粒级钛精矿烧结存在制粒效果差,燃耗高,生产效率低的问题。通过理化检测及物相分析,确定了钛精矿烧结的固结机理、烧结基本规律及制粒... 详细信息

针对钛精矿粒度细,电炉冶炼损耗高的问题,着重对细粒级钛精矿烧结造块工艺进行了试验探索与研究。细粒级钛精矿烧结存在制粒效果差,燃耗高,生产效率低的问题。通过理化检测及物相分析,确定了钛精矿烧结的固结机理、烧结基本规律及制粒效果差的原因。优化制粒试验表明,通过添加熔剂,优化燃料配比及水分,并对钛精矿进行磨制处理后,钛精矿烧结混合料制粒效果得到改善。通过降低烧结料层,对磨制后的钛精矿造球并采用在料面分加燃料的方式进行烧结,烧结技术经济指标得到显著改善,钛精矿烧结+1 mm比例由50.3%提高至89.4%,利用系数由0.177 t/(m2·h)提高至0.712 t/(m2·h)。从烧结试验结果看,采用该方法进行钛精矿烧结,烧结过程钛精矿硫脱除率在40%左右,影响TiO2品位约3~4个百分点。

关键词：钛精矿烧结细粒级脱硫效率

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分布式内存管理系统的研究与设计

计算机工程 2006年第19期32卷 111-113页

作者：王育坚刘辰田星北京联合大学信息学院北京100101 北京邮电大学计算机科学与技术学院北京100876

针对中小型企业数据处理的特点,提出了一种基于局域网的分布式内存管理系统,介绍了系统的数据组织方式、设计原理和各功能实体的具体实现。系统利用局域网内存资源存储数据,解决了磁盘输入/输出的性能瓶颈问题。把数据分成包,通过包管... 详细信息

针对中小型企业数据处理的特点,提出了一种基于局域网的分布式内存管理系统,介绍了系统的数据组织方式、设计原理和各功能实体的具体实现。系统利用局域网内存资源存储数据,解决了磁盘输入/输出的性能瓶颈问题。把数据分成包,通过包管理实体对内存资源进行管理,利用同步协议机制保持主包和备包的同步。测试结果表明,利用系统对数据进行处理的效率是本机硬盘的5到7倍。

关键词：分布式计算内存管理包开放最短路径优先

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盘式制动器闭环耦合模型耦合刚度的优化

汽车工程 2016年第11期38卷 1357-1361,1375页

作者：高普杜永昌王宇健北京理工大学机械与车辆学院北京100081 清华大学汽车安全与节能国家重点实验室北京100084

为确定盘式制动器关键耦合界面的耦合刚度,首先进行制动器静态加压加载工况下的模态试验得到其模态参数,然后运用非线性优化方法使模型计算与试验结果间的误差达到最小,从而得到与实际使用工况尽量一致的耦合刚度。最后将优化后的模型... 详细信息

为确定盘式制动器关键耦合界面的耦合刚度,首先进行制动器静态加压加载工况下的模态试验得到其模态参数,然后运用非线性优化方法使模型计算与试验结果间的误差达到最小,从而得到与实际使用工况尽量一致的耦合刚度。最后将优化后的模型和原模型计算结果与台架试验结果进行对比。结果表明,利用本文优化后的耦合刚度计算得到的不稳定模态结果与台架制动噪声试验结果更接近,验证了本文方法的合理性和有效性。

关键词：盘式制动器制动噪声闭环耦合模型耦合刚度优化

A Gray Fingerprint Image Compression Scheme Using Wavelet Transform

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Systems Science and Systems Engineering 1998年第2期8卷 75-83页

作者： TANG Jinshan Beijing University of Posts and Telecommunication,100876 China wang yujian Vocational And Technical Teacher’s College,Beijing Union University,100011 China

In this paper, an adaptive quantizer is proposed for gray fingerprint image compression based on biorthogonal wavelet *** quantization scheme is implemented by optimization method: try to find an optimized quntization table to minimize the overall distortion while keeping the compression ratio close to desired value. Since the l 2 norm of the quantization error is not preserved through the biorthogonal transform, a quantization error estimation formula considering the characteristic value of reconstruction filters is derived to incorporate the adaptive quantization *** scheme includes the calculation of q in as its special case. Simulation results demonstrate the efficiency of our scheme.

关键词： Fingerpint compression Biorthogonal Optimization Quantization