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计算机视觉技术赋能大学英语课堂展示中的学习投入研究

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新疆师范大学学报（哲学社会科学版） 2025年第2期46卷 144-151页

作者：谭苏燕王晋军广州大学外国语学院广东广州510010

学习投入是预测学习者学习效果的重要指标,学术界对其与课堂展示间的相关性研究鲜有涉猎。文本以某综合性大学303名非英语专业本科生为研究对象,采用人工智能与计算机视觉技术模型YOLOv7对大学英语课堂中的课堂展示实录进行学习投入多... 详细信息

学习投入是预测学习者学习效果的重要指标,学术界对其与课堂展示间的相关性研究鲜有涉猎。文本以某综合性大学303名非英语专业本科生为研究对象,采用人工智能与计算机视觉技术模型YOLOv7对大学英语课堂中的课堂展示实录进行学习投入多模态数据分析,并辅以问卷调查,形成双向印证。研究发现,学生课堂展示中的行为投入、认知投入和情感投入值均等于或高于3.78,投入结果均值达4.01,说明学生在课堂展示中的学习投入情况良好。此外,不同时段课堂展示对学生行为投入的影响显著,学生专注度及参与度在课堂前10分钟的课堂展示中效果最佳。文本为课堂展示的有效性提供了智能化、多模态、多维度的实证支持,为课堂教学的数智技术应用提供了新视角。

关键词：大学英语课堂展示学习投入计算机视觉技术展示时段

沉积温度对氮化铝压电薄膜性能影响及机制分析

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光电子·激光 2025年第1期36卷 107-112页

作者：郭燕刘小军王进南京理工大学泰州科技学院天津三安光电有限公司

高频光电通信器件对压电材料特性要求越来越高，氮化铝（AlN）薄膜由于其优异的压电特性而备受关注，高取向高压电AlN薄膜沉积工艺优化成为其应用拓展的瓶颈技术之一，众多制备工艺参数中温度是影响AlN薄膜晶格取向的关键参数之一。本... 详细信息

高频光电通信器件对压电材料特性要求越来越高，氮化铝（AlN）薄膜由于其优异的压电特性而备受关注，高取向高压电AlN薄膜沉积工艺优化成为其应用拓展的瓶颈技术之一，众多制备工艺参数中温度是影响AlN薄膜晶格取向的关键参数之一。本文采用磁控溅射的方法沉积AlN薄膜，研究了沉积温度对AlN薄膜晶体取向及压电性能的影响，X射线衍射（X-ray diffraction, XRD）测试结果表明，250℃下可获得（100）取向AlN,300℃下AlN则优先（002）取向；压电测试结果表明，250℃下压电常数d*33达最大值0.79 V,表现出较优的压电特性。基于原子力显微镜（atomic force microscopy, AFM）结果及温度对价键稳定性影响分析探索了温度对其生长的影响机制。

关键词：氮化铝(AlN) 衬底温度取向生长压电特性

Nonlinear Inverse Relations of the Bell Polynomials via the Lagrange Inversion Formula (Ⅱ)

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Journal of Systems Science & Complexity 2023年第1期36卷 96-116页

作者： MA Xinrong wang jin Department of Mathematics Soochow UniversitySuzhou 215006China Department of Mathematics Zhejiang Normal UniversityJinhua 321004China

In this paper,by means of the classical Lagrange inversion formula,the authors establish a general nonlinear inverse relation as the solution to the problem proposed in the paper[***,Nonlinear inverse relations for the Bell polynomials via the Lagrange inversion formula,*** Seq.,Vol.22(2019),Article 19.3.8].As applications of this inverse relation,the authors not only find a short proof of another nonlinear inverse relation due to Birmajer,et al.(2012),but also set up a few convolution identities concerning the Mina polynomials.

关键词： Bell polynomial convolution identity formal power series Lagrange inversion formula Mina polynomial nonlinear inverse relation recurrence relation

New SI and precision measurements:an interview with Tianchu Li

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National Science Review 2020年第12期7卷 1837-1840页

作者： jin wang the Wuhan Institute of Physics and Mathematics Chinese Academy of Sciences

On 13–16 November 2018,the 26 th General Conference of Weights and Measures（CGPM） was held in *** conference adopted Resolution A on ’Revision of the International System of Units（SI）.’ According to Resolution A:four of the SI basic units,namely kilograms,amps,kelvin and mole,are defined by the Planck constant h,the basic charge constant e,the Boltzmann constant k and the Avogadro constant N;,

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Instability of roll nonlinear system with structural clearance in rolling process

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Journal of Iron and Steel Research International 2023年第1期30卷 112-125页

作者： jin-xing Cui Yan Peng jin wang National Engineering Research Center for Equipment and Technology of Cold Rolled Strip School of Mechanical EngineeringYanshan UniversityQinhuangdao 066004HebeiChina

The vibration instability of the nonlinear dynamic system of the rolls considering the structural clearance was theoretically investigated,which is caused by the roll assembly accuracy deviation in the hot rolling ***,the dynamic rolling force model was established based on the Wekbrod model under the influence of the roll grinding deviation and the stability of the deformation ***,the horizontal and vertical direction coupling dynamic model of the work roll was established considering the structural clearance between the roll and mill ***,the nonlinear dynamic equation was solved by the Runge-Kutta *** simulation results show that the dynamic system presents the nonlinear vibration characteristics,which shows that the instability of the system is a slowly varying response process with the characteristics of self-excited vibration and forced ***,the comparison results show the consistency between the simulation and the test.

关键词： Roll grinding accuracy Dynamic rolling force Structural clearance Collision Rolling mill instability

Impact Analyses of Wind Farm on Performances of Transmission Line Relay Protection

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电力系统自动化 2012年第8期36卷 148-153页

作者： wang, jin Zhang, Baohui School of Electrical Engineering Xi'an Jiaotong University Xi'an 710049 China

A simulation system for power grid with concentrated large-scale wind farm integration is established based on the electro-magnetic transient model of wind turbine equipped with doubly-fed induction generator (DFIG),which is built by real-time digital simulator (RTDS).Using the hardware communication interface of RTDS,a closed-loop testing experiment is accomplished to study the impacts of large-scale wind farms on the existing relay protection devices for wind farm outgoing transmission *** paper points out problems existing in current relay protection devices as follows:fault phase selector can select unwanted phase due to the changes of fault features caused by special network connection of wind farms;blocking condition for distance protections needs to be re-examined due to the weak power-feed characteristics of wind farms;and power frequency parameter based relay protection devices cannot accurately operate due to the special transient voltage and current characteristics of wind farms during fault *** lay the foundation for improving the performances of the existing relay protection device and developing new principle relay protection.

关键词：继电保护装置大型风电场保护性能输电线路双馈风力发电机双馈感应发电机实时数字仿真线路保护装置

Ultrafiltration with in-line coagulation for the removal of natural humic acid and membrane fouling mechanism

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Journal of Environmental Sciences 2006年第5期18卷 880-884页

作者： wang jin wang Xiao-chang Department of Municipal and Environmental Engineering Beijing Jiaotong University Beijing 100044 China School of Environmental and Municipal Engineering Xi＇an University of Architecture and Technology Xi＇an 710055 China

Experimental and theoretical analysis were made on the natural humic acid removal and the membrane fouling of ultrafiltration （UF） with in-line coagulation. The results showed dissolved organic carbon （DOC） and UV254 removals by the UF with in-line coagulation at pH 7 were increased from 28% to 53% and 40% to 78% in comparison with direct UF treatment respectively. At the same time, the analysis of high performance liquid chromatography showed that UF with coagulation had significant improvement of removal of humic acid with molecular weights less than 6000 Da in particular. Compared to direct UF, the in-line coagulation UF also kept more constant permeate flux and very slight increase oftransmembrane pressure during a filtration circle. Two typical membrane fouling models were used by inducing two coefficients Kc and Kp corresponding to cake filtration model and pore narrowing model respectively. It was found that membrane fouling by pore-narrowing effect was effectively alleviated and that by cake-filtration was much decreased by in-line coagulation. Under the condition of coagulation prior to ultrafiltration at pH 7, the cake layer formed on the membrane surface became thicker, but the membrane filtration resistance was lower than that at pH 5 with the extension of operation time.

关键词： natural humic acid ultrafiltration (UF) in-line coagulation high performance liquid chromatography (HPLC) membrane fouling

Ferroelectric materials for vibrational energy harvesting

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Science China(Technological Sciences) 2016年第7期59卷 1012-1022页

作者： SONG JunDong wang jin Division of Energy and Environment in Graduate School at Shenzhen Tsinghua University

Energy harvesting is an appealing technology that makes use of the ambient energy which is otherwise wasted. Piezoelectric materials directly convert the elastic energy to the electric energy, and thus have a great advantage in scavenging vibrational energy for simplicity in device structure with relatively high power density. This paper provides an overview on the research of piezoelectric materials in energy harvesting in recent decades, from basics of piezoelectricity and working principle of energy harvesting with piezoelectric materials, to the progress of development of high-performance piezoelectrics including ceramics, single crystals and polymers, then to experimental attempts on the device fabrication and optimization, finally to perspective applications of piezoelectric energy harvesting(PEH). The criteria for selection of materials for PEH applications are introduced. Not only the figure of merit but also maximum allowable stress of materials are taken into account in the evaluation of their potential in achieving high energy density and output power density. The influence of the device configuration on the performance is also acknowledged and discussed. The magnitude and distribution of induced stress in the piezoelectric unit upon excitation by the vibration source play an important role in determining the output power density and can be tuned via proper design of device configuration without changing its resonant frequency. Approaches to address the issue of frequency match accompanying with the resonant mode are illustrated with literature examples. Usage of PEH devices can be extended to a variety of vibration sources in everyday life as well as in nature. Some appealing applications of PEH, such as in implantable and wearable devices, are reviewed.

关键词： energy harvesting ferroelectric materials piezoelectricity figure of merit applications

Transient performance and intelligent combination control of a novel spray cooling loop system

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Chinese Journal of Aeronautics 2013年第5期26卷 1173-1181页

作者： wang jin Li Yunze wang Jun School of Aeronautic Science and Engineering Beihang University

Effective thermal control systems are essential for the reliable working of insulated gate bipolar transistors （IGBTs） in many applications. A novel spray cooling loop system with integrated sintered porous copper wick （SCLS-SPC） is proposed to meet the requirements of higher device level heat fluxes and the harsh environments in some applications such as hybrid, fuel cell vehicles and aerospace. Fuzzy logic and proportional-integral-derivative （PID） policies are applied to adjust the electronic temperature within a safe working range. To evaluate the thermal control effect, a mathematical model of a 4-node thermal network and pump are established for predicting the dynamics of the SCLS-SPC. Moreover, the transient response of the 4 nodes and vapor mass flowrate under no control, PID and Fuzzy-PID are numerically investigated and discussed in detail.

关键词： Fuzzy logic Insulated gate bipolar transistor (IGBT) Sintered porous copper Spray cooling Thermal control