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Liu X.,Key Laboratory of Micro Nano Measurement Manipulation and Physics | Liu X.,Science and Technology on Inertial Laboratory | Liu X.,Beihang University | Dong Q.,Key Laboratory of Micro Nano Measurement Manipulation and Physics | And 4 more authors.
Guangxue Jishu/Optical Technique | Year: 2015

Based on the TDX-200 transmission electron microscope (TEM), the axial magnetic field distribution of objective lens is simulated using ANSYS software while magnetic circuit has gap defect, hollow defect and bulge defect. Forth more the objective lens incentive and coefficient of spherical aberration are simulated by MEBS software, and the influence of magnetic circuit defect on resolution of objective lens is analyzed. The results show that, the effect of hollow defect on objective lens resolution is greater than gap defect and bugle defect. 200 kV acceleration voltage, the change of actual resolution to the ideal resolution can reach 9.68% when the objective lens has a diameter of 0.5 mm semicircle concave ring flaw. ©, 2014, Editorial Board of Optical Technique. All right reserved.


Lian Z.,Beihang University | Fang X.,Key Laboratory of Micro Nano Measurement Manipulation and Physics | Han W.,Beihang University | Yu J.,Beihang University | And 3 more authors.
Fusion Engineering and Design | Year: 2016

Tungsten coatings were prepared using pulse electrodeposition on the molybdenum substrates. Effects of variations in current density on surface morphology, thickness distribution and crystal orientation of the coatings were investigated. The results indicate that with the current density increasing, the grain size of tungsten coatings first decreases, then increases; while the deposited thickness increases all the time. And all of tungsten coatings exhibit the preferred orientation of (200) plane. Moreover, the polished tungsten coating and bulk tungsten were exposed to low energy (80 eV) and high flux (7.2 × 1020 D/m2/s) deuterium plasma in a linear plasma device (Simulator of Tokamak Edge Plasma, STEP). Deuterium (D) retention was measured by thermal desorption spectroscopy (TDS). It is found that blisters on the tungsten coating are much fewer than that on the bulk tungsten. TDS spectroscopy of the tungsten coating reveals one D2 release peak at 740 K, while the bulk tungsten has two D2 release peaks at 500 K and 660 K. The amount of deuterium retention in the tungsten coating is lower. © 2016 Elsevier B.V.


Liu X.-P.,Beihang University | Liu X.-P.,Science and Technology on Inertial Laboratory | Liu X.-P.,Key Laboratory of Micro nano Measurement Manipulation and Physics | Dong Q.-L.,Beihang University | And 8 more authors.
Jiliang Xuebao/Acta Metrologica Sinica | Year: 2015

The magnetic field distribution varies with the dislocation of multiple coaxial coils. The basic Biot-Savart Law and the superposition theorem is applied to work out the calculation formulas of the magnetic field. Furthermore, the numerical solution of the variation magnetic induction were calculated using MATLAB, and the field plots were drew. Based on these, the effects of the coil winding rules on the magnetic field distribution is judged and reasonable theory suggests about the magnetic field incentive is given. Calculation results show that the variation of axial magnetic induction is the order of 10-11T, and the relative change of magnetic field on center plan is less than 1%, while the ration of coil offset and average radius is not more than 0.04. ©, 2015, Chinese Society for Measurement. All right reserved.


Yu H.-Y.,Beihang University | Zhang C.-X.,Beihang University | Zhang C.-X.,Key Laboratory of Micro nano Measurement Manipulation and Physics | Feng L.-S.,Beihang University | And 3 more authors.
Guangdianzi Jiguang/Journal of Optoelectronics Laser | Year: 2012

The scheme of silicon-based integrated optical gyroscope is proposed firstly, and the curve radius and transmission loss of the curve waveguide are calculated theoretically. The essential parameters which are the width and length, are simulated with the relationship with transmission loss, and the "K" shape coupler is designed by the R-soft simulation based on the theoretical analysis result. The experimental setup is constructed, and the loss and the optical mode are tested, respectively. The loss measurement results show that the loss is 0.014 dB/cm, which validates the theoretical calculation result that the transmission can be neglected when the ratio of l 2/h is greater than 5000. Finally, the optical mode is tested by beam-scan, which shows the perfect fitting result with the ideal Gauss mode curve.


Peng L.,Beihang University | Peng L.,Key Laboratory of Micro Nano Measurement Manipulation and Physics | Feng L.,Beihang University | Feng L.,Key Laboratory of Micro Nano Measurement Manipulation and Physics | And 4 more authors.
Proceedings of SPIE - The International Society for Optical Engineering | Year: 2011

Polarization-maintaining fiber (PMF) has attracted great attentions not only due to its ability to realize coherent optic communication with ultrahigh-capacity, but also because it can be widely employed in high-precise fiber-optic sensors and optic information processors, e.g., fiber-optic gyroscope and fiber-optic amperemeter. Distinct with common monomode optic fibers, additional birefringence is introduced in the PMF, minimizing the effect of mode coupling between two orthogonal polarization modes in optic fibers. Thus, light polarization can be maintained after long distance transmission in the PMF. However, beat-length, which reflects the characteristic of induced birefringence and evaluates the ability of polarization maintaining, is one of the most important parameters for PMF. Accurate measurement of PMF beat length becomes more and more important along with the expanding of its application field. The uniqueness of the measurement results determines the identity of PMF fabrication and the resolution of fiber-optic sensors. The existing measurement methods for PMF beat length are introduced first. Most testing setups are established by several individual components, which lead to complicated setup, inconvenient testing, and unsteady measurement. In this paper, a novel all fiber beat length measurement system is presented, where optic source, integrated optic modulator, stress apply structure, polarization detector, and polarization indicator of output light are included. The configuration and working principle of the whole system, and the designing and realization of each components, are addressed in the paper. Furthermore, the influence on measurement results by the relative direction between applied stress and principal axis of the optic fiber is analyzed. Moreover, optimized designs, including polarized light incidence, pressure apply, and precise movement systems, are performed, which ensure the identical pressure apply direction in the moving process. Finally, measurement of PMF samples is carried out on experimental setup. In comparison with the other existing system, due to its all fiber light incidence structure, the novel beat length measurement system represents great stability and high reliability. © 2011 SPIE.


Dong Q.-L.,Beihang University | Dong Q.-L.,Science and Technology on Inertial Laboratory | Dong Q.-L.,Key Laboratory of Micro nano Measurement Manipulation and Physics | Liu X.-P.,Beihang University | And 6 more authors.
Jiliang Xuebao/Acta Metrologica Sinica | Year: 2013

The magnetic field distribution varies with the dislocation of coaxial drive coils. The basic Biot-Savart law and the superposition theorem is applied to work out the calculation formulas of the magnetic field, and with the help of MATLAB the numerical solution of the variation magnetic induction is calculated and the field plots is drawn. Based on these, the effects of the coil winding rules on the magnetic field distribution were judged and reasonable theory suggests is given about the magnetic field incentive and maintenance calculation results show that the effect of dislocation of a double coaxial coil on magnetic field is less than the order of 10-6 that is acceptable to actual application currently.


Liu H.-L.,Science and Technology on Inertial Laboratory | Liu H.-L.,Key Laboratory of Micro nano Measurement Manipulation and Physics | Liu H.-L.,Beihang University | Wang Y.,The Aerospace Corporation | And 4 more authors.
Zhongguo Guanxing Jishu Xuebao/Journal of Chinese Inertial Technology | Year: 2013

Spatial resonator is the key element of MOEMS gyroscope. Adjustment of the micro-mirrors of spatial resonator is important for realization of the resonator. An adjustment method based on coupling theory for the vertical micro-mirrors in the spatial resonator was presented. For the production of the vertical micro-mirror by micro-processing technology, the principle of the regulation based on coupling was used to complete the space-conditioning as a useful means, rather than avoiding the coupling volume. The basic structure of regulation and the method of implementation were introduced, and the spatial resonator made up of this structure was simulated and analyzed by MATLAB and ANSYS respectively. The results show that the structure based on the method could implement the micro-mirror's spatial regulation with high precision. For the adjustments of the MOEMS gyroscope spatial resonator, this method has its own reliable stability and higher integration, which provide a new method for realization of the spatial resonator MOEMS gyroscope.


Li Y.,Beihang University | Zhang L.,Key Laboratory of Micro Nano Measurement Manipulation and Physics | Shan G.,Key Laboratory of Micro Nano Measurement Manipulation and Physics | Song Z.,Beihang University | And 4 more authors.
American Journal of Physics | Year: 2016

Atomic force microscopes are a key tool in nanotechnology that overcome the limitations of optical microscopes and provide imaging capabilities with nanoscale resolution. We have developed an atomic force microscope that uses an inexpensive quartz tuning fork as a micro cantilever. Because of its ease of operation and its open structure, it can be easily customized by students. Due to its low costs, it is possible that every student in the course has access to one setup, allowing all students to obtain deep insights into nanotechnology and to understand the principles of atomic force microscopy. © 2016 American Association of Physics Teachers.


Zhou Y.,Beihang University | Shang G.,Beihang University | Cai W.,Beihang University | Yao J.-E.,Key Laboratory of Micro nano Measurement Manipulation and Physics
Review of Scientific Instruments | Year: 2010

A cantilevered bimorph-based resonance-mode scanner for high speed atomic force microscope (AFM) imaging is presented. The free end of the bimorph is used for mounting a sample stage and the other one of that is fixed on the top of a conventional single tube scanner. High speed scanning is realized with the bimorph-based scanner vibrating at resonant frequency driven by a sine wave voltage applied to one piezolayer of the bimorph, while slow scanning is performed by the tube scanner. The other piezolayer provides information on vibration amplitude and phase of the bimorph itself simultaneously, which is used for real-time data processing and image calibration. By adjusting the free length of the bimorph, the line scan rate can be preset ranging from several hundred hertz to several kilohertz, which would be beneficial for the observation of samples with different properties. Combined with a home-made AFM system and a commercially available data acquisition card, AFM images of various samples have been obtained, and as an example, images of the silicon grating taken at a line rate of 1.5 kHz with the scan size of 20 μm are given. By manually moving the sample of polished Al foil surface while scanning, the capability of dynamic imaging is demonstrated. © 2010 American Institute of Physics.

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