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激光熔覆温度场模拟计算和测量

上海有色金属 2001年第3期22卷 110-114页

作者：平志纲严彪徐政同济大学材料科学与工程学院上海200092

本文从热传导方程出发 ,描述了国内外近期激光熔覆温度场模型 ,主要方法有解析法、有限单元法和有限差分法 ;在此基础上提出了适合本实验的温度场模型 ,并利用红外热成像技术实际测量了Zn Al合金表面等离子喷涂Al2 O3 陶瓷层后激光熔覆... 详细信息

本文从热传导方程出发 ,描述了国内外近期激光熔覆温度场模型 ,主要方法有解析法、有限单元法和有限差分法 ;在此基础上提出了适合本实验的温度场模型 ,并利用红外热成像技术实际测量了Zn Al合金表面等离子喷涂Al2 O3 陶瓷层后激光熔覆的表面温度场。

关键词：激光熔覆温度场模型红外热成像

Preparation and characterization of Fe_2O_3-CeO_2-TiO_2/γ-Al_2O_3 catalyst for degradation dye wastewater

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Journal of Environmental Sciences 2006年第6期18卷 1189-1192页

作者： LIU yan SUN De-zhi CHENG Lin LI yan-ping School of Municipal and Environmental Engineering Harbin Institute of Technology Harbin 150090 China

In order to develop a catalyst with high activity for catalytic wet oxidation （CWO） process at room temperature and atmospheric pressure, Fe2O3-CeO2-TiO2/γ-Al2O3 catalyst was prepared by consecutive impregnation method and the prepared parameters were optimized. The structure of the catalyst was characterized by BET, XRF, SEM and XPS technologies, and the actual wastewater was used to investigate the catalytic activity of Fe2O3-CeO2-TiO2/γ-Al2O3 in CWO process. The experimental results showed that the prepared catalyst exhibited good catalytic activity when the doping amount of Ti was 1.0 wt% （the weight ratio of Ti to carriers）, and the middle product, Fe2O3-CeO2-TiO2/γ-Al2O3, was calcined in 450℃ for 2 h. The CWO experiment for treating actual dye wastewater indicated that the COD, color and TOC of actual wastewater were decreased by 62.23%, 50.12% and 41.26% in 3 h, respectively, and the ratio of BOD5/COD was increased from 0.19 to 0.30.

关键词： catalytic wet oxidation (CWO) Fe2O3-CeO2-TiO2/γ-Al2O3 catalyst dye wastewater treatment

从教学技能掌握到教学素养发展:新时代好教师的核心追求

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黑龙江高教研究 2025年第1期43卷 22-30页

作者：单妍李志厚广东药科大学广东广州510006 广州华商学院广东广州511300 华南师范大学广东广州510631

教学素养是教育者经过专业学习和课堂教学实践培养和磨炼之后所表现出来的专业化教学素质与涵养,是教师专业所特有的内在素质和外在表现。它与教学技能、教学能力不同,在其基础上还包括教育信念、专业知能、教学眼光、通化意识、教育思... 详细信息

教学素养是教育者经过专业学习和课堂教学实践培养和磨炼之后所表现出来的专业化教学素质与涵养,是教师专业所特有的内在素质和外在表现。它与教学技能、教学能力不同,在其基础上还包括教育信念、专业知能、教学眼光、通化意识、教育思维、创新追求以及教育家精神等方面的素养。通过对教学素养与教学技能、教学能力异同的比较分析,探讨教育者教学素养发展的影响因素、形成条件、发展机制及其相关的问题,为有效促进新时代教师教学素养的发展以及新质教育力的探索提供有力参考。

关键词：教学技能教学能力教学素养教学创新新质教育力通化意识

Channel pruning on frequency response

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Science China(Information Sciences) 2025年第1期68卷 159-170页

作者： Hang LIN Yifan PENG Lin BIE Chenggang yan Xibin ZHAO Yue GAO School of Software Tsinghua University School of Automation Hangzhou Dianzi University

Network pruning has a significant role in reducing network parameters and accelerating the inference time of the network. Some existing methods prune the network based on the frequency of the data, and finally obtain a sub-network with high accuracy. However, according to our experimental analysis, different frequencies of information in the data contribute differently to the accuracy of the model, and using this information directly for pruning without making a selection will lead to incorrect results. We believe that pruning should retain the convolutional kernels in the network that process important information, while those kernels that process unimportant information should be removed. In this paper, we first investigate the meaning of each frequency band information in the spectrum and their contribution to the prediction accuracy of the network,and according to these results, we propose a new pruning method based on frequency response(PFR). Our PFR finds and removes the convolutional kernels in the network that specialize in processing unimportant information, resulting in a compact neural network model. PFR obtains significant experimental results on different datasets, for example, a 56.0% raduction of float points operations(FLOPs) on Res Net-50 and only 0.37% of Top-1 accuracy degradation on the Image Net dataset.

关键词： deep learning model compression filter pruning channel pruning frequency response

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Revealing and predicting the long-term biomechanical response of orthokeratology by developing a patient-specific computational model

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Science China(Physics,Mechanics & Astronomy) 2025年第1期Mechanics & Astronomy) .卷 156-168页

作者： Yifeng Li Zhuoran yang Ziming yan Huibin Shi Zhanli Liu Kaijie Wang Department of Engineering Mechanics School of Aerospace Engineering Tsinghua University Beijing Tongren Eye Center Beijing Tongren Hospital Capital Medical University Beijing Ophthalmology & Visual Sciences Key Lab

Orthokeratology(OK) is widely used for effective myopia correction and control. However, the incomplete understanding of its biomechanical mechanisms makes OK lens fitting rely heavily on clinician judgment, complicating accurate predictions of treatment outcomes. In this paper, we performed clinical experiments and numerical analysis to study corneal deformation modes and long-term changes in central corneal thickness. Clinical experiments were conducted on 194 Chinese myopic patients under OK treatment for 3 months. Based on the experimental data, a patient-specific computational biomechanical model for OK was established and validated. Specifically, the anisotropic mechanical properties of the cornea were incorporated into the model to describe the significant difference between its shear modulus(29.5 kPa) and tensile modulus(768.4 kPa). Additionally, a viscohyperelastic material model with a prolonged corneal relaxation time of 5.6 h was developed to capture the long-term deformation response. The results show that corneal thickness reduction in OK is primarily due to out-of-plane shear deformation,influenced by the cornea's low shear resistance. Modeling the extended corneal relaxation time is crucial for predicting long-term biomechanical responses. The computational model effectively captures long-term changes in central corneal thickness, potentially improving OK lens fitting accuracy.

关键词： orthokeratology computational biomechanical model long-term viscoelasticity myopia correction

Phase-Division-Based Dynamic Optimization of Linkages for Drawing Servo Presses

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Chinese Journal of Mechanical Engineering 2017年第6期30卷 1426-1437页

作者： zhi-Gang Zhang Li-ping Wang yan-Ke Cao JIER Machine-Tool Group Co. Ltd Department of Mechanical Engineering Tsinghua University

Existing linkage-optimization methods are designed for mechanical presses; few can be directly used for servo presses, so development of the servo press is limited. Based on the complementarity of linkage opti- mization and motion planning, a phase-division-based linkage-optimization model for a drawing servo press is established. Considering the motion-planning principles of a drawing servo press, and taking account of work rating and efficiency, the constraints of the optimization model are constructed. Linkage is optimized in two modes： use of either constant eccentric speed or constant slide speed in the work segments. The performances of optimized link- ages are compared with those of a mature linkage SL4- 2000A, which is optimized by a traditional method. The results show that the work rating of a drawing servo press equipped with linkages optimized by this new method improved and the root-mean-square torque of the servo motors is reduced by more than 10%. This research pro- vides a promising method for designing energy-saving drawing servo presses with high work ratings.

关键词： Drawing servo press Linkage optimization Phase-division Motion planning

Comparison between the surface defects caused by Al_2O_3 and TiN inclusions in interstitial-free steel auto sheets

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International Journal of Minerals,Metallurgy and Materials 2019年第2期26卷 178-185页

作者： Rui Wang yan-ping Bao zhi-jie yan Da-zhao Li yan Kang School of Materials Science and Engineering North University of China State Key Laboratory of Advanced Metallurgy University of Science and Technology Beijing

Al_2O_3 and TiN inclusions in interstitial-free(IF) steel deteriorate the properties of the steel. To decrease the defects of cold-rolled sheet, it is important to clearly distinguish between the degrees of damage caused by these two inclusions on the surface quality of the steel. In this study, a nanoindenter was used to test the mechanical properties of the inclusions, and the distribution and size of the inclusions were obtained by scanning electron microscopy(SEM). It was found that when only mechanical properties are considered, TiN inclusions are more likely to cause defects than Al_2O_3 inclusions of the same size during the rolling process. However, Al_2O_3 inclusions are generally more inclined to cause defects in the rolling process than TiN inclusions because of their distribution characteristic in the thickness direction. The precipitation of Al_2O_3 and TiN was obtained through thermodynamical calculations. The growth laws of inclusions at different cooling rates were calculated by solidification and segregation models. The results show that the precipitation regularity is closely related to the distribution law of the inclusions in IF slabs along the thickness direction.

关键词： interstitial-free steel inclusions nanoindenter inclusion precipitation

PERSISTENCE, EXTINCTION AND STABILITY FOR NONLINEAR PLANKTON ALLELOPATHY MODEL WITH DELAYED NEGATIVE FEEDBACKS

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International Journal of Biomathematics 2012年第2期5卷 157-196页

作者： yan-ping LIU zhi-XUE LUO College of Science Gansu Agricultural University Lanzhou 730070P.R.China Department of Mathematics Lanzhou Jiaotong University Lanzhou 730070P.R.China

By the techniques of comparison argument and Lyapunov-like functionals, some criteria about persistence and extinction of the species are obtained. And then, with the help of constructing Lyapunov functionals and some new analysis method, sufficient conditions, provided with the form of average value of a function, to guarantee the stability of the system are derived. Finally, some examples together with their numerical simulations show the feasibility of these main results. Our conclusions are different from many existing forms for nonlinear competitive systems.

关键词： Persistence extinction stability toxicant Lyapunov functional delay.

Integration of Electrical Properties and Polarization Loss Modulation on Atomic Fe–N‑RGO for Boosting Electromagnetic Wave Absorption

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Nano-Micro Letters 2025年第2期17卷 517-532页

作者： Kaili Zhang Yuefeng yan Zhen Wang Guansheng Ma Dechang Jia Xiaoxiao Huang Yu Zhou State Key Laboratory of Precision Welding&Joining of Materials and Structures Harbin Institute of TechnologyHarbin 150001People’s Republic of China School of Materials Science and Engineering Harbin Institute of TechnologyHarbin 150001People’s Republic of China MIIT Key Laboratory of Advanced Structural‑Functional Integration Materials&Green Manufacturing Technology Harbin Institute of TechnologyHarbin 150001People’s Republic of China

Developing effective strategies to regulate graphene’s conduction loss and polarization has become a key to expanding its application in the electromagnetic wave absorption(EMWA)*** on the unique energy band structure of graphene,regulating its bandgap and electrical properties by introducing heteroatoms is considered a feasible ***,metal-nitrogen doping reduced graphene oxide(M–N-RGO)was prepared by embedding a series of single metal atoms M–N_(4) sites(M=Mn,Fe,Co,Ni,Cu,Zn,Nb,Cd,and Sn)in RGO using an N-coordination atom-assisted *** composites had adjustable conductivity and polarization to optimize dielectric loss and impedance matching for efficient EMWA *** results showed that the minimum reflection loss(RL_(min))of Fe–N-RGO reaches−74.05 dB(2.0 mm)and the maximum effective absorption bandwidth(EAB_(max))is 7.05 GHz(1.89 mm)even with a low filler loading of only 1 wt%.Combined with X-ray absorption spectra(XAFS),atomic force microscopy,and density functional theory calculation analysis,the Fe–N_(4) can be used as the polarization center to increase dipole polarization,interface polarization and defect-induced polarization due to d-p orbital hybridization and structural ***,electron migration within the Fe further leads to conduction loss,thereby synergistically promoting energy *** study demonstrates the effectiveness of metal-nitrogen doping in regulating the graphene′s dielectric properties,which provides an important basis for further investigation of the loss mechanism.

关键词： Electromagnetic wave absorption Fe-N-RGO Dipole polarization Conduction loss Impedance matching