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Ball Tips of Micro/Nano Probing Systems:A Review

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Chinese Journal of Mechanical Engineering 2017年第2期30卷 222-230页

作者： Ruijun LI Chen CHEN Dandong LI Kuang-Chao FAN Zhenying CHENG Qiangxian HUANG Xueming DANG School of Instrument Science and Opto-electronics Engineering Hefei University of Technology Department of Mechanical Engineering National Taiwan University

To satisfy the measuring demands for the micro components of the industry, micro/nano probing systems with various ball tips have been developed. However, most of them cannot be used to measure the real micro geometrical features high precisely because the parameters of the ball tips are not appropriate. The ball tips with a diameter of less than 100 μm, a sphericity and eccentricity of far less than 1 μm are required urgently. A review on the state-of-the-art of ball tips of micro/nano probing systems is presented. The material characteristics and geometric parameters of now available ball tips are introduced sepa- rately. The existing fabrication methods for the ball tips are demonstrated and summarized. The ball tips＇ future trends, which are smaller diameter, better sphericity and smaller eccentricity, are proposed in view of the practical requirements of high-precision measurement for micro geometrical features. Some challenges have to be faced in future, such as the promotion and high-precision measurement for the small ball tip＇s sphericity and eccentricity. Fusion method without the gravity effect when the molten ball tip solidifying is a more suitable way to fabricate a small diameter ball tip together with a shaft.

关键词： Ball tip · Probe - Micro/nano CMMs · Microcomponents

A semantic vector map-based approach for aircraft positioning in GNSS/GPS denied large-scale environment

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Defence technology（防务技术） 2024年第4期34卷 1-10页

作者： Chenguang Ouyang Suxing Hu Fengqi Long Shuai Shi Zhichao Yu Kaichun Zhao Zheng You Junyin Pi Bowen Xing state key laboratory of precision Measurement technology and instruments Tsinghua UniversityBeijing 100084China School of Mechanical and Information Engineering China University of Mining and Technology(Beijing)Beijing 100083China

Accurate positioning is one of the essential requirements for numerous applications of remote sensing data,especially in the event of a noisy or unreliable satellite *** this end,we present a novel framework for aircraft geo-localization in a large range that only requires a downward-facing monocular camera,an altimeter,a compass,and an open-source Vector Map(VMAP).The algorithm combines the matching and particle filter *** vector and correlation between two building contour vectors are defined,and a coarse-to-fine building vector matching(CFBVM)method is proposed in the matching stage,for which the original matching results are described by the Gaussian mixture model(GMM).Subsequently,an improved resampling strategy is designed to reduce computing expenses with a huge number of initial particles,and a credibility indicator is designed to avoid location mistakes in the particle filter *** experimental evaluation of the approach based on flight data is *** a flight at a height of 0.2 km over a flight distance of 2 km,the aircraft is geo-localized in a reference map of 11,025 km~2using 0.09 km~2aerial images without any prior *** absolute localization error is less than 10 m.

关键词： Large-scale positioning Building vector matching Improved particle filter GPS-Denied Vector map

Preparation of Sulfur-doped PANI/TiO2 Nanowires and Its Sensing Properties to Mercury

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Chemical Research in Chinese Universities 2015年第4期31卷 581-584页

作者： WANG Dong LIU Xiaomeng FANG Zhenxing LI Jian SUN Mojie Department of Chemical Engineering Northeast Dianli University Jilin 132012 P. R. China state key laboratory of Inorganic Synthesis and Preparative Chemistry College of Chemistry Jilin University Changchun 130012 P R China state key laboratory of precision measuring technology and instruments Tianjin University Tianjin 300192 P RChina

TiO2 nanowires were successfully prepared via a simple hydrothermal method and a layer of sulfurized polyaniline（PANI） was loaded onto their surface to prepare a sensor of elemental mercury at room temperature. The sulfurized PANI/TiO2 composite sensor has a high sensitivity to mercury in a range of density from 5.57 mg/m3 to 126.18 mg/m3 at room temperature. The response time and recovery time are relatively short. We also investigated the sensitivity and response time to other interfering gases, such as NO2, SO2 and NH3. And the sulfurized PANI/TiO2 composite material shows a good selectivity for element mercury. The microscopic structure of the sensor was inves- tigated via X-ray diffraction（XRD）, scanning electron microscopy（SEM） and energy dispersive X-ray analysis （EDAX）. The sulfurized PANI/TiO2 composite material shows a high sensitive response, and good selectivity to element mercury, which is promising for the application in the detection of element mercury.

关键词： Hg sensor PANI/TiO2 Hg pollution Mercury emissions monitoring

3D Characteristic Diagram of Acoustically Induced Surface Vibration with Different Landmines Buried

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Transactions of Tianjin University 2016年第4期22卷 367-373页

作者：吴智强张燕丽王驰朱俊徐文文袁志文 Department of precision Mechanical Engineering Shanghai UniversityShanghai 200072China North Automatic Control technology Research Institute Taiyuan 030006China Science and technology on Near-Surface Detection laboratory Wuxi 214035China state key laboratory of precision measuring technology and instruments Tianjin UniversityTianjin 300072China Shanghai Public Utility School Shanghai 200030China

The 3D characteristic diagram of acoustically induced surface vibration was employed to study the influence of different buried landmines on the acoustic detection signal. By using the vehicular experimental system for acoustic landmine detection and the method of scanning detection, the 3D characteristic diagrams of surface vibration were measured when different objects were buried underground, including big plastic landmine, small plastic landmine, big metal landmine and bricks. The results show that, under the given conditions, the surface vibration amplitudes of big plastic landmine, big metal landmine, small plastic landmine and bricks decrease in turn. The 3D characteristic diagrams of surface vibration can be used to further identify the locations of buried landmines.

关键词： acoustic-to-seismic(A/S) coupling acoustic landmine detection acoustic resonance surface vibration velocity

Anomalous Variation of Beat Frequency in a Dual Frequency He-Ne Laser

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Chinese Physics Letters 2016年第2期33卷 51-54页

作者：刘维新孙明哲 Shandong Provincial key laboratory of Optical Astronomy and Solar-Terrestrial Environment Institute of Space SciencesShandong University

The beat frequency in a dual frequency He-Ne laser varies while the resonant cavity length is tuned. As to the laser with two longitudinal modes, the variation amplitude is commonly less than 500 kHz, proven by experiments and theories. This study reveals an anomalous variation of the beat frequency when a piece of element is put into the cavity and is aligned with the laser axis. Consequently the variation amplitude couM reach 22 MHz, several dozen times larger than that without the intra-cavity element. This cannot be explained only by laser mode pulling and pushing effects. Some influencing factors are investigated experimentally, including the tilted angle of the element and the distance between its surface and cavity mirror. The qualitative analysis is discussed, which agrees with the experimental results.

关键词： of on as it or Anomalous Variation of Beat Frequency in a Dual Frequency He-Ne Laser in is

Surface-enhanced Raman scattering on nanodiamond-derived carbon onions

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Nanotechnology and precision Engineering 2019年第1期2卷 35-39页

作者： Ying Song Zongwei Xu Andreas Rosenkranz Mathias Rommel Changkun Shi Fengzhou Fang state key laboratory of precision measuring technology & instruments Centre of MicroNano Manufacturing Technology Tianjin University Department of Chemical Engineering Biotechnology and Materials Universidad de Chile Fraunhofer Institute for Integrated Systems and Device technology (IISB)

Annealing nanodiamonds(ND) at high temperatures up to 1700 ℃ is a common method to synthesize carbon onions. The transformation from NDs to carbon onions is particularly interesting because of carbon onions' potential in the field of tribology and their application in ultra-charge/discharge devices. In this paper, a novel surface-enhanced Raman scattering technique that involves coating the sample with nanoscopic gold particles is proposed to characterize the NDs after different annealing treatments. Conventional Raman and surfaceenhanced Raman spectra were obtained, and the changes of peak parameters as the function of annealing temperature were evaluated. It was found that the widths of the D and the G peaks decreased with increasing annealing temperature, reflecting an improved order in the sp^2-hybridized carbon during the transformation from NDs to carbon onions. After annealing at 1700 ℃, the sp^2?carbon was highly ordered, indicating desirable electrical conductivity and lubricity. With increasing annealing temperature, the D peak showed a blue shift of almost30 cm^(-1), while the G peak merely shifted by 5 cm^(-1). For annealing temperatures above 1100 ℃, an increase of intensity ratio ID/IGwas observed. Compared to the uncoated area, red shifts of 0.5-2 cm^(-1) and of 5-9 cm^(-1) for the G and D peaks, respectively, were detected for the gold-coated area, which was due to the coupling of the plasmons and the phonons of the samples.

关键词： Nanodiamonds Carbon onions Surface-enhanced Raman scattering LOPC mode

Numerical Simulation of Surface Acoustic Wave and Detection of Surface Crack in Steel

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Transactions of Tianjin University 2011年第4期17卷 254-258页

作者：林滨张磊多伦雷.丹特李艳宁傅兴胡小唐 School of Mechanical Engineering Tianjin University state key laboratory of precision measuring technology and instruments Tianjin University

The surface acoustic wave （SAW） propagating in a sample of steel is simulated by using finite element method （FEM）. The waves are excited by a load function with propagation properties such as phase velocity disper- sion and wide bandwidth. A two-dimensional model consisting of surface defects loaded with a wideband 50--200 M Hz and short time 0.1 gs displacement function is investigated in the time and frequency domains. By transient dy- namic analysis, Fourier transform and dispersion calculation, snapshots of propagating wave and responses from sens- ing points are presented. It is indicated that this supervision approach is sensitive to the surface cracks and reflections.

关键词： surface acoustic wave steel numerical simulation displacement load defect

Ramsey-coherent population trapping Cs atomic clock based on lin‖lin optical pumping with dispersion detection

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Chinese Physics B 2019年第7期28卷 174-183页

作者： Peng-Fei Cheng Jian-Wei Zhang Li-Jun Wang Department of Physics Tsinghua University Beijing 100084 China state key laboratory of precision Measurement technology and instruments Tsinghua University Beijing 100084 China Department of precision instruments Tsinghua University Beijing 100084 China

A Cs vapor cell-based atomic clock that uses a lin‖lin pumping scheme with dispersion detection is reported. This atomic clock shows potential for high performance because of its high contrast pumping scheme, and for miniaturization because of its simple architecture. The experimental setup and optimal operating parameters for the clock are *** current fractional frequency stability is measured to be 1.3 × 10^-12/■ up to 20s and reaches 3.1 × 10^-13 at 200 s. We have thoroughly investigated the related noise sources that affect clock frequency stability at the 1s and 100s levels. The investigation shows that the laser frequency noise limits the clock frequency stability significantly. The clock performance can be further improved by technically upgrading the laser frequency stabilization setup.

关键词： Ramsey-coherent population trapping(CPT) atomic clock frequency stability noise analysis

Real-time frequency transfer system over ground-to-satellite link based on carrier-phase compensation at 10-16 level

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Chinese Physics B 2021年第8期30卷 260-268页

作者： Hui-Jian Liang Shi-Guang Wang Yu Bai Si-Chen Sun Li-Jun Wang Department of Electronic Engineering Tsinghua UniversityBeijing 100084China state key laboratory of precision Measurement technology and instruments Tsinghua UniversityBeijing 100084China Department of precision instruments Tsinghua UniversityBeijing 100084China Department of Physics Tsinghua UniversityBeijing 100084China

We demonstrate a novel and stable frequency transfer scheme over ground-to-satellite link based on real-time carrier-phase detection and *** performed a zero-baseline measurement with the designed system,an uninterrupted frequency standard signal is recovered in the reception station without additional post-correction of delay error caused in the route,which is because the phase error of the entire route is tracked and compensated continuously in *** achieve this goal,we employed two carriers in the system and the differential signal is transferred in order to eliminate the instability results from the local oscillator at the satellite transponder as well as the common-mode noise induced in the transfer route and microwave *** stability of 3×10^(-16) with an integration time of 1 day was achieved and the time fluctuation during one day was measured to be about±20 *** sources and possible solutions are *** zero-baseline method shows a promising result for real-time satellite-based time and frequency transfer and deserves further research to find whether it works between long-baseline stations.

关键词： frequency transfer ground-to-satellite link carrier-phase compensation