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折叠特征的低频Helmholtz共振器的数值计算与实验研究

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噪声与振动控制 2024年第3期44卷 289-294页

作者：付天宇陈长征张大成孙鲜明沈阳工业大学机械工程学院沈阳110870 宁波坤博测控有限公司浙江宁波315200

Helmholtz共振器可有效抑制共振频率处噪声。提出一种具备折叠特征的Helmholtz共振器。基于有限元分析,计算共振器在100至800 Hz频带内传输损失曲线,并根据传递函数法进行实验,验证数值计算的准确性。结果表明,在等体积条件下,具备折叠... 详细信息

Helmholtz共振器可有效抑制共振频率处噪声。提出一种具备折叠特征的Helmholtz共振器。基于有限元分析,计算共振器在100至800 Hz频带内传输损失曲线,并根据传递函数法进行实验,验证数值计算的准确性。结果表明,在等体积条件下,具备折叠特征Helmholtz共振器有效频率更低,且在共振频率处传递损失达35 dB。使用响应面法对该共振器结构参数进行相关性分析,并获取结构参数对声学特征的影响。研究表明具备折叠特征的Helmholtz共振器能够有效降低共振频率,在低频降噪控制工程领域中具有广阔应用前景。

关键词：振动与波有限元分析折叠特征低频降噪 Helmholtz共振器

An electrical-coupling-suppressing MEMS gyroscope with feed-forward coupling compensation and scalable fuzzy control

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Science China(Information Sciences) 2017年第4期60卷 180-190页

作者： Chunhua HE Jimeng zhang Qiancheng ZHAO Qinwen HUANG Zhenchuan YANG dacheng zhang Guizhen YAN National Key Laboratory of Science and Technology on Micro/Nano Fabrication Institute of Microelectronics Science and Technology on Reliability Physics and Application of Electronic Component Laboratory No.5 Electronics Research Institute of the Ministry of Industry and Information Technology

This paper proposes a novel electrical coupling suppressing and drive closed loop control method for a MEMS gyroscope with feed-forward coupling compensation(FCC) and scalable fuzzy control. Theoretical analysis of the novel method is described in detail, and it is very simple to realize. Experimental results demonstrate that the electrical anti-resonant peaks located at the amplitude-frequency and phase-frequency responses are both eliminated by FCC control, and the height of the amplitude resonant peak increases more than 24 d B over 1800 Hz span. In addition, the overshoot of the transient response with scalable fuzzy control is smaller than 5%, and the settling time is less than 15 ms. The stabilities of the resonant amplitude and phase of the drive-mode velocity with scalable fuzzy control are about 15 ppm and 11 ppm, respectively. The scale factor of the gyroscope is measured to be 33.98 m V/deg/s with nonlinearity about 0.08%. Furthermore, the bias instability of the gyroscope with wavelet analysis is improved to be about 6.3 deg/h from 25.2 deg/h of the gyroscope without wavelet analysis.

关键词： MEMS gyroscope electrical coupling suppressing anti-resonance feed-forward coupling compen sation scalable fuzzy control

基于超短脉冲激光刻蚀的双解耦MEMS陀螺仪调频技术研究

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传感器与微系统 2024年第7期43卷 39-42页

作者：刘玉县侯帅康赵前程崔健张大成北京大学集成电路学院北京100871 郑州大学电气与信息工程学院河南郑州450001

以双解耦双质量硅微陀螺仪为主要研究对象,从微观结构入手,分析其工作原理和双解耦运动模型,并提出影响模态特征频率的因素。提出一种改变陀螺仪弹性梁结构厚度来调整其特征频率的方法,建立模型通过Comsol软件仿真陀螺仪梁厚度变化对特... 详细信息

以双解耦双质量硅微陀螺仪为主要研究对象,从微观结构入手,分析其工作原理和双解耦运动模型,并提出影响模态特征频率的因素。提出一种改变陀螺仪弹性梁结构厚度来调整其特征频率的方法,建立模型通过Comsol软件仿真陀螺仪梁厚度变化对特征频率的影响关系,并选择皮秒激光刻蚀系统刻蚀陀螺弹性梁厚度,测试其两模态特征频率。测试结果表明:对应频率变化符合理论推导和仿真趋势。

关键词：微机械陀螺结构解耦频率调节短脉冲激光

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Electrochemical reduction of graphene oxide films:Preparation,characterization and their electrochemical properties

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Chinese Science Bulletin 2012年第23期57卷 3045-3050页

作者： zhang Xiong zhang dacheng CHEN Yao SUN XianZhong MA YanWei Institute of Electrical Engineering Chinese Academy of Sciences Beijing 100190 China

Graphene oxide (GO) film was electrochemically reduced by a cyclic voltammetry technique in 6 mol L-1 KOH aqueous *** reduced graphene oxide (ER-GO) film was characterized by X-ray diffraction,X-ray photoelectron spectroscopy,atomic force microscopy,and Raman *** oxygen content (with the O/C atomic ratio of 1.29%) was significantly decreased after electrochemical *** ER-GO film exhibited a specific capacitance of 152 F g-1 at the current density of 5 A g-1 and a good rate ***,the ER-GO film showed an excellent cycling *** capacitance retention remained 99% after 3000 cycles at the current density of 10 A g-1.

关键词： graphene, electrochemical reduction, electrochemical double-layer capacitor, electrode material

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陶瓷碎片的激光诱导击穿光谱快速鉴别方法

量子电子学报 2024年第3期41卷 543-552页

作者：王韶仪冯中琦许文忠侯佳佳路智勇张勇剑张大成西安电子科技大学光电工程学院陕西西安710071 陕西历史博物馆陕西西安710061 馆藏壁画保护修复与材料科学研究国家文物局重点科研基地陕西历史博物馆陕西西安710061 陕西省考古研究院陕西西安710054

对陶瓷碎片进行在线、快速分类检测在考古学中有着重要的意义。激光诱导击穿光谱技术(LIBS)具有非接触、快速、无需样品制备等特点,非常适用于陶瓷碎片的在线分类检测。实验利用自主研制的微型纳秒激光器搭建了微型LIBS系统,对陶瓷碎片... 详细信息

对陶瓷碎片进行在线、快速分类检测在考古学中有着重要的意义。激光诱导击穿光谱技术(LIBS)具有非接触、快速、无需样品制备等特点,非常适用于陶瓷碎片的在线分类检测。实验利用自主研制的微型纳秒激光器搭建了微型LIBS系统,对陶瓷碎片进行快速检测,并使用主成分分析(PCA)提取出陶瓷光谱数据的主成分与载荷从而对古代陶瓷碎片样品进行分析。分析结果表明利用PCA可以对陶瓷碎片进行识别,但相近的元素组成不能被准确区分。进一步使用线性判别分析(LDA)进行分类后发现,古代陶瓷碎片样品的光谱均被正确分类。最后应用LDA分类算法对全部18块陶瓷碎片样品进行分类鉴别,总分类正确率达到98.15%。研究结果表明,利用微型LIBS装备可快速、准确识别文物碎片,可为文物碎片的保护与修复提供有效帮助。

关键词：光谱学激光诱导击穿光谱陶瓷碎片主成分分析线性判别分析

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A novel robust design method for the sense mode of a MEMS vibratory gyroscope based on fuzzy reliability and Taguchi design

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Science China(Technological Sciences) 2017年第2期60卷 317-324页

作者： HE ChunHua ZHAO QianCheng HUANG QinWen LIN LongTao YANG ZhenChuan zhang dacheng YAN GuiZhen National Key Laboratory of Science and Technology on Micro/Nano Fabrication Institute of MicroelectronicsPeking University Science and Technology on Reliability Physics and Application of Electronic Component Laboratory No.5 Electronics Research Institute of the Ministry of Industry and Information Technology

This paper proposes a novel robust design method for the sense mode of a MEMS vibratory gyroscope based on fuzzy reliability and Taguchi design. The principles of fuzzy reliability and Taguchi design are both introduced and described in detail. Experimental results demonstrate that the signal to noise ratio of the robust design scheme is better than those of the other experimental *** the full temperature range from -40 to 80°C, the temperature sensitivities of phase margin, gain margin, sensitivity margin,the maximum amplitude of open loop system, bandwidth of closed loop system, and the performance function of the robust design system are all smaller than those of the original design system. Meanwhile, the temperature sensitivity of the bandwidth of the robust design system is improved to 126 from 1075 ppm/°C. Moreover, the bias drift over the full temperature range of the robust design system is improved to 61°/h from 179°/h.

关键词： MEMS gyroscope fuzzy reliability Taguchi design force rebalance control mode-matching

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四种稻米中镉检测方法比较研究

粮食科技与经济 2024年第1期49卷 93-96页

作者：张大诚李发启彭灿胡丽谭小文常德市粮油食品质量检测中心湖南常德415000

采用石墨炉原子吸收法、固体直接进样电热蒸发原子吸收光谱法、电化学阳极溶出伏安法和X射线荧光光谱法测定稻米中镉含量,对4种定量检测方法的准确度、精密度以及相对误差进行了比较分析。研究结果表明,固体直接进样电热蒸发原子吸收光... 详细信息

采用石墨炉原子吸收法、固体直接进样电热蒸发原子吸收光谱法、电化学阳极溶出伏安法和X射线荧光光谱法测定稻米中镉含量,对4种定量检测方法的准确度、精密度以及相对误差进行了比较分析。研究结果表明,固体直接进样电热蒸发原子吸收光谱法操作简单,无需化学前处理,单样检测时间在3 min左右,快速高效,精密度良好,可信度高。通过4种检测方法对比,固体直接进样电热蒸发原子吸收光谱法的测试结果准确度高,与国家标准方法相比相对误差多数在±10%以内,重复6次测定的RSD为3.9%,可作为一种新型快速检测稻米中镉的方法,具备方便快速、准确度高、重复性好等优点,在基层可广泛应用。

关键词：稻米镉固体直接进样石墨炉原子吸收法 X射线荧光光谱法电化学阳极溶出伏安法

On Robust Cross-view Consistency in Self-supervised Monocular Depth Estimation

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Machine Intelligence Research 2024年第3期21卷 495-513页

作者： Haimei Zhao Jing zhang Zhuo Chen Bo Yuan dacheng Tao School of Computer Science University of SydneySydney2008Australia Shenzhen International Graduate School Tsinghua UniversityShenzhen518055China School of Information Technology&Electrical Engineering University of QueenslandBrisbane4072Australia

Remarkable progress has been made in self-supervised monocular depth estimation (SS-MDE) by exploring cross-view consistency, e.g., photometric consistency and 3D point cloud consistency. However, they are very vulnerable to illumination variance, occlusions, texture-less regions, as well as moving objects, making them not robust enough to deal with various scenes. To address this challenge, we study two kinds of robust cross-view consistency in this paper. Firstly, the spatial offset field between adjacent frames is obtained by reconstructing the reference frame from its neighbors via deformable alignment, which is used to align the temporal depth features via a depth feature alignment (DFA) loss. Secondly, the 3D point clouds of each reference frame and its nearby frames are calculated and transformed into voxel space, where the point density in each voxel is calculated and aligned via a voxel density alignment (VDA) loss. In this way, we exploit the temporal coherence in both depth feature space and 3D voxel space for SS-MDE, shifting the “point-to-point” alignment paradigm to the “region-to-region” one. Compared with the photometric consistency loss as well as the rigid point cloud alignment loss, the proposed DFA and VDA losses are more robust owing to the strong representation power of deep features as well as the high tolerance of voxel density to the aforementioned challenges. Experimental results on several outdoor benchmarks show that our method outperforms current state-of-the-art techniques. Extensive ablation study and analysis validate the effectiveness of the proposed losses, especially in challenging scenes. The code and models are available at https://***/sunnyHelen/RCVC-depth.

关键词： 3D vision depth estimation cross-view consistency self-supervised learning monocular perception

The classification of plants by laser-induced breakdown spectroscopy based on two chemometric methods

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Plasma Science and Technology 2020年第7期22卷 92-97页

作者： Zhongqi FENG dacheng zhang Bowen WANG Jie DING Xuyang LIU Jiangfeng ZHU School of Physics and Optoelectronic Engineering Xidian UniversityXi’an 710071People’s Republic of China

The applications of laser-induced breakdown spectroscopy(LIBS) on classifying complex natural organics are relatively limited and their accuracy still requires *** this work,to study the methods on classification of complex organics,three kinds of fresh leaves were measured by LIBS.100 spectra from 100 samples of each kind of leaves were measured and then they were divided into a training set and a test set in a ratio of 7:*** algorithms of chemometric methods including the partial least squares discriminant analysis(PLS-DA) and principal component analysis Mahalanobis distance(PCA-MD) were used to identify these *** using 23 lines from 16 elements or molecules as input data,these two methods can both classify these three kinds of leaves *** classification accuracies of training sets are both up to 100% by PCA-MD and *** classification accuracies of the test set are 93.3% by PCA-MD and 97.8% by *** means that PLS-DA is better than PCA-MD in classifying plant *** the components in PLS-DA process are more suitable for classification than those in PCA-MD *** think that this work can provide a reference for plant traceability using LIBS.

关键词： laser-induced breakdown spectroscopy principal component analysis Mahalanobis distance partial least squares discriminant analysis classification of complex organics