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  • AIP Publishing  (18)
  • 1
    Online Resource
    Online Resource
    Core structures of 〈001〉 {110} edge dislocations in BaTiO3
    AIP Publishing ; 2015
    In:  AIP Advances Vol. 5, No. 7 ( 2015-07-01)
    Details
    In: AIP Advances, AIP Publishing, Vol. 5, No. 7 ( 2015-07-01)
    Abstract: The core structures of two types of & lt;001 & gt; {110} edge dislocations in BaTiO3 have been observed and investigated at the atomic scale by using aberration-corrected transmission electron microscopy (AC-TEM). The edge dislocations are both dissociated into two collinear partial edge dislocations bounding a complex stacking fault (SF). While the partial dislocations have the same Burgers vector, 12[001], the dissociation planes are different for the two types of edge dislocations, with one at the BaO plane and the other at the TiO2 plane. The SF energy has been estimated by measuring the SF width.
    Type of Medium: Online Resource
    ISSN: 2158-3226
    URL: Article
    DOI: 10.1063/1.4927637
    Language: English
    Publisher: AIP Publishing
    Publication Date: 2015
    detail.hit.zdb_id: 2583909-3
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  • 2
    Online Resource
    Online Resource
    Luminescence study of (112̄0) GaN film grown by metalorganic chemical-vapor deposition
    AIP Publishing ; 2003
    In:  Journal of Applied Physics Vol. 93, No. 1 ( 2003-01-01), p. 316-319
    Details
    In: Journal of Applied Physics, AIP Publishing, Vol. 93, No. 1 ( 2003-01-01), p. 316-319
    Abstract: Investigations on photoluminescence properties of (112̄0) GaN grown on (11̄02) Al2O3 substrate by metalorganic chemical-vapor deposition are reported. Several emission lines not reported before are observed at low temperature. The sharp peak at 3.359 eV is attributed to the exciton bound to the neutral acceptor. Another peak at 3.310 eV represents a free-to-bound, probably a free electron-to-acceptor, transition. The 3.241 and 3.170 eV lines are interpreted as phonon replica lines of the 3.310 eV line. The phonon energy is 70 meV, consistent with the energy of transverse optical E1 phonon. The optical properties of the lines are analyzed.
    Type of Medium: Online Resource
    ISSN: 0021-8979 , 1089-7550
    URL: Article
    DOI: 10.1063/1.1529296
    Language: English
    Publisher: AIP Publishing
    Publication Date: 2003
    detail.hit.zdb_id: 220641-9
    detail.hit.zdb_id: 3112-4
    detail.hit.zdb_id: 1476463-5
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  • 3
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    Online Resource
    Integral back-stepping active disturbance rejection control for piezoelectric stick-slip drive nanopositioning stage
    AIP Publishing ; 2023
    In:  Review of Scientific Instruments Vol. 94, No. 7 ( 2023-07-01)
    Details
    In: Review of Scientific Instruments, AIP Publishing, Vol. 94, No. 7 ( 2023-07-01)
    Abstract: Piezoelectric stick-slip driven nanopositioning stage (PSSNS) with nanometer resolution has been widely used in the field of micro-operation. However, it is difficult to achieve nanopositioning over large travel, and its positioning accuracy is affected by the hysteresis characteristics of the piezoelectric elements, external uncertain disturbances, and other nonlinear factors. To overcome the above-mentioned problems, a composite control strategy combining stepping mode and scanning mode is proposed in this paper, and an integral back-stepping linear active disturbance rejection control (IB-LADRC) strategy is proposed in the scanning mode control phase. First, the transfer function model of the system in the micromotion part was established, and then the unmodeled part of the system and the external disturbance were treated as the total disturbance and extended to a new system state variable. Second, a linear extended state observer was used as the core of the active disturbance rejection technique to estimate displacement, velocity, and total disturbance in real time. In addition, by introducing virtual control variables, a new control law was designed to replace the original linear control law and improve the positioning accuracy and robustness of the system. Furthermore, the effectiveness of the IB-LADRC algorithm was verified by simulation comparison experiments and experimentally validated on a PSSNS. Finally, experimental results show that the IB-LADRC is a practical solution for a controller capable of handling disturbances during the positioning of a PSSNS with a positioning accuracy of less than 20 nm, which essentially remains constant under load.
    Type of Medium: Online Resource
    ISSN: 0034-6748 , 1089-7623
    URL: Article
    DOI: 10.1063/5.0150909
    Language: English
    Publisher: AIP Publishing
    Publication Date: 2023
    detail.hit.zdb_id: 209865-9
    detail.hit.zdb_id: 1472905-2
    SSG: 11
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  • 4
    Online Resource
    Online Resource
    Hardness, elastic, and electronic properties of chromium monoboride
    AIP Publishing ; 2015
    In:  Applied Physics Letters Vol. 106, No. 22 ( 2015-06-01)
    Details
    In: Applied Physics Letters, AIP Publishing, Vol. 106, No. 22 ( 2015-06-01)
    Abstract: We report high-pressure synthesis of chromium monoboride (CrB) at 6 GPa and 1400 K. The elastic and plastic behaviors have been investigated by hydrostatic compression experiment and micro-indentation measurement. CrB is elastically incompressible with a high bulk modulus of 269.0 (5.9) GPa and exhibits a high Vickers hardness of 19.6 (0.7) GPa under the load of 1 kg force. Based on first principles calculations, the observed mechanical properties are attributed to the polar covalent Cr-B bonds interconnected with strong zigzag B-B covalent bonding network. The presence of metallic Cr bilayers is presumably responsible for the weakest paths in shear deformation.
    Type of Medium: Online Resource
    ISSN: 0003-6951 , 1077-3118
    URL: Article
    DOI: 10.1063/1.4922147
    RVK:
    UA 1000
    Language: English
    Publisher: AIP Publishing
    Publication Date: 2015
    detail.hit.zdb_id: 211245-0
    detail.hit.zdb_id: 1469436-0
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  • 5
    Online Resource
    Online Resource
    Enhancing the efficiency of the topological phase transitions in spin–orbit photonics
    AIP Publishing ; 2022
    In:  Applied Physics Letters Vol. 120, No. 18 ( 2022-05-02)
    Details
    In: Applied Physics Letters, AIP Publishing, Vol. 120, No. 18 ( 2022-05-02)
    Abstract: A light beam reflected and refracted at a sharp interface can acquire a momentum-dependent Pancharatnam–Berry (PB) phase, which produces a topological phase transition from one kind of spin–orbit interaction (e.g., spin-controlled vortex generation) to another (e.g., photonic spin-Hall effect). However, this process is extremely inefficient and difficult to observe directly in experiments, which also hinders its applications. Here, we propose to enhance significantly the topological phase transitions by c-cut uniaxial crystals. We first give a full-wave theory to describe the spin–orbit interactions of a beam passing through a c-cut uniaxial crystal and experimentally observe the topological phase transition process of the transmitted beam when the angle between the beam propagation direction and the optical axis direction changes. It is found that the efficiency of the spin–orbit interactions caused by the momentum-dependent PB phase can be increased as high as 50%, which is much larger than that at isotropic sharp interfaces. Our findings provide an alternative approach for manipulating the spin and orbital angular momenta of light and exhibit potential applications in the future spin–orbit photonic components.
    Type of Medium: Online Resource
    ISSN: 0003-6951 , 1077-3118
    URL: Article
    DOI: 10.1063/5.0086930
    RVK:
    UA 1000
    Language: English
    Publisher: AIP Publishing
    Publication Date: 2022
    detail.hit.zdb_id: 211245-0
    detail.hit.zdb_id: 1469436-0
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  • 6
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    Online Resource
    Growth of crack-free GaN films on Si(111) substrate by using Al-rich AlN buffer layer
    AIP Publishing ; 2004
    In:  Journal of Applied Physics Vol. 96, No. 9 ( 2004-11-01), p. 4982-4988
    Details
    In: Journal of Applied Physics, AIP Publishing, Vol. 96, No. 9 ( 2004-11-01), p. 4982-4988
    Abstract: GaN epilayers were grown on Si(111) substrate by metalorganic chemical vapor deposition. By using the Al-rich AlN buffer which contains Al beyond stoichiometry, crack-free GaN epilayers with 1 μm thickness were obtained. Through x-ray diffraction (XRD) and secondary ion mass spectroscopy analyses, it was found that a lot of Al atoms have diffused into the under part of the GaN epilayer from the Al-rich AlN buffer, which results in the formation of an AlxGa1−xN layer at least with 300 nm thickness in the 1 μm thick GaN epilayer. The Al fraction x was estimated by XRD to be about 2.5%. X-ray photoelectron spectroscopy depth analysis was also applied to investigate the stoichiometry in the Al-rich buffer before GaN growth. It is suggested that the underlayer AlxGa1−xN originated from Al diffusion probably provides a compressive stress to the upper part of the GaN epilayer, which counterbalances a part of tensile stress in the GaN epilayer during cooling down and consequently reduces the cracks of the film effectively. The method using the Al diffusion effect to form a thick AlGaN layer is really feasible to achieve the crack-free GaN films and obtain a high crystal quality simultaneously.
    Type of Medium: Online Resource
    ISSN: 0021-8979 , 1089-7550
    URL: Article
    DOI: 10.1063/1.1787588
    Language: English
    Publisher: AIP Publishing
    Publication Date: 2004
    detail.hit.zdb_id: 220641-9
    detail.hit.zdb_id: 3112-4
    detail.hit.zdb_id: 1476463-5
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  • 7
    Online Resource
    Online Resource
    Piezoelectric energy harvesting in coupling-chamber excited by the vortex-induced pressure
    AIP Publishing ; 2016
    In:  Applied Physics Letters Vol. 109, No. 7 ( 2016-08-15)
    Details
    In: Applied Physics Letters, AIP Publishing, Vol. 109, No. 7 ( 2016-08-15)
    Abstract: The performance of a piezoelectric energy harvester with a coupling chamber was investigated under vortex-induced pressure. The harvester consisted of a power chamber, a buffer, and a storage chamber. Different types of vortex (i.e., clockwise or counter-clockwise) could be induced by changing the volume ratio between the power chamber and the storage chamber. The peak voltage of the harvester could be tuned by changing the volume ratio. For example, under a pressure of 0.30 MPa, input cycle of 2.0 s, and flow rate of 200 l/min, the peak voltage decreased from 79.20 to 70.80 V with increasing volume ratio. The optimal volume ratio was 2.03, which resulted in the formation of a clockwise vortex. The corresponding effective power through a 600 kΩ resistor was 1.97 mW.
    Type of Medium: Online Resource
    ISSN: 0003-6951 , 1077-3118
    URL: Article
    DOI: 10.1063/1.4961528
    RVK:
    UA 1000
    Language: English
    Publisher: AIP Publishing
    Publication Date: 2016
    detail.hit.zdb_id: 211245-0
    detail.hit.zdb_id: 1469436-0
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  • 8
    Online Resource
    Online Resource
    A stick–slip linear actuator with high speed and nano-resolution by resonance/non-resonance hybrid driving
    AIP Publishing ; 2022
    In:  Review of Scientific Instruments Vol. 93, No. 5 ( 2022-05-01)
    Details
    In: Review of Scientific Instruments, AIP Publishing, Vol. 93, No. 5 ( 2022-05-01)
    Abstract: To achieve high speed, nano-resolution, and large stroke, a resonance/non-resonance hybrid piezoelectric stick–slip actuator with a lever-type flexure hinge (LTFH-PSSA) is proposed in this work. The actuator can achieve high speed and large stroke in the resonance mode by the stick–slip working principle and achieve nano-resolution in the non-resonant mode by the direct drive working principle. The excitation electrical signals used in the two working modes are the sine waveform and half-sine waveform, respectively. Compared with the traditional sawtooth waveform, the excitation signal of the sine and half-sine waveforms have no sudden change of voltage, which are more conducive to reduce the impact and vibration of the system. Moreover, a series of static analysis and modal analysis of the stator are carried out by the finite element method. The experimental system is built to test the output characteristics of the LTFH-PSSA. In the resonance state by the stick–slip working principle, the impedance analysis and frequency characteristic test of the LTFH-PSSA are carried out, which states that the tested resonance frequency agrees well with the simulated ones. When the locking force, the voltage, and the frequency are 2 N, 100 Vp–p, and 1850 Hz, the speed of the LTFH-PSSA is up to 52.71 mm/s, and the backward motion is suppressed completely as well. In the non-resonance state, the resolution can reach 2.19 nm and 2.69 nm in the forward and backward motion, respectively. So far, the proposed actuator ranks first in speed and resolution among all reported LTFH-PSSAs.
    Type of Medium: Online Resource
    ISSN: 0034-6748 , 1089-7623
    URL: Article
    DOI: 10.1063/5.0082660
    Language: English
    Publisher: AIP Publishing
    Publication Date: 2022
    detail.hit.zdb_id: 209865-9
    detail.hit.zdb_id: 1472905-2
    SSG: 11
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  • 9
    Online Resource
    Online Resource
    Performance improvement of smooth impact drive mechanism at low voltage utilizing ultrasonic friction reduction
    AIP Publishing ; 2016
    In:  Review of Scientific Instruments Vol. 87, No. 8 ( 2016-08-01)
    Details
    In: Review of Scientific Instruments, AIP Publishing, Vol. 87, No. 8 ( 2016-08-01)
    Abstract: The smooth impact drive mechanism (SIDM) actuator is traditionally excited by a saw-tooth wave, but it requires large input voltages for high-speed operation and load capacity. To improve the output characteristic of the SIDM operating at low input voltage, a novel driving method based on ultrasonic friction reduction technology is proposed in this paper. A micro-amplitude sinusoidal signal with high frequency is applied to the rapid deformation stage of the traditional saw-tooth wave. The proposed driving method can be realized by a composite waveform that includes a driving wave (D-wave) and a friction regulation wave (FR-wave). The driving principle enables lower input voltage to be used in normal operation, and the principle of the proposed driving method is analyzed. A prototype of the SIDM is fabricated, and its experimental system is established. The tested results indicate that the actuator has suitable velocity and load characteristics while operating at lower input voltage, and the load capacity of the actuator is 2.4 times that of an actuator excited by a traditional saw-tooth driving wave.
    Type of Medium: Online Resource
    ISSN: 0034-6748 , 1089-7623
    URL: Article
    DOI: 10.1063/1.4960392
    Language: English
    Publisher: AIP Publishing
    Publication Date: 2016
    detail.hit.zdb_id: 209865-9
    detail.hit.zdb_id: 1472905-2
    SSG: 11
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  • 10
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    Online Resource
    Breakthrough the physical barrier on spatial resolution in Raman distributed fiber sensing using chaotic correlation demodulation
    AIP Publishing ; 2023
    In:  APL Photonics Vol. 8, No. 7 ( 2023-07-01)
    Details
    In: APL Photonics, AIP Publishing, Vol. 8, No. 7 ( 2023-07-01)
    Abstract: Raman distributed optical fiber temperature sensors possess the unique capability of measuring spatial environmental temperatures, which can be of great interest in several fields of application. The key physics barrier to spatial resolution for most optical time-domain reflection (OTDR) systems is the positioning principle of pulse-time-flight. It obtains the spatial resolution of the existing Raman distributed optical fiber temperature sensor, with the kilometer-level sensing distance being limited to the meter-level. Here, we propose a chaotic laser Raman distributed optical fiber temperature sensing scheme that replaces the traditional OTDR positioning principle used for more than 40 years with the chaotic correlation positioning principle. The proposed scheme possesses the characteristics of the chaos Raman scattering light excited by the chaos signal along the sensing fiber. A novel measurement mechanism based on chaotic time-domain differential reconstruction and chaotic correlation demodulation is developed, and a relationship between the temperature variation information and the chaotic correlation peak is experimentally demonstrated. Importantly, the proposed optics mechanism scheme overcomes the physics limitation of the effect of a wide pulse width on sensing spatial resolution; its spatial resolution is optimized from 50 to 0.3 m under the modulation of a 500 ns pulse width. This scheme provides a new concept for chaos optics and fiber sensing research.
    Type of Medium: Online Resource
    ISSN: 2378-0967
    URL: Article
    DOI: 10.1063/5.0153542
    Language: English
    Publisher: AIP Publishing
    Publication Date: 2023
    detail.hit.zdb_id: 2857268-3
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