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  • AIP Publishing  (44)
  • 1
    Online Resource
    Online Resource
    Design, analysis, and testing of Petrel acoustic autonomous underwater vehicle for marine monitoring
    AIP Publishing ; 2022
    In:  Physics of Fluids Vol. 34, No. 3 ( 2022-03-01)
    Details
    In: Physics of Fluids, AIP Publishing, Vol. 34, No. 3 ( 2022-03-01)
    Abstract: Autonomous underwater vehicles (AUVs) provide a unique and cost-effective platform for conducting ocean acoustic measurements and surveys such as marine mammal monitoring, extensive area seafloor topography survey, and fish stock survey. The small and medium-sized AUVs combine load-carrying capability, motion, and range and allow for timescale observations that are difficult to achieve with traditional acoustic observation platforms. However, self-noise is still an unavoidable challenge for AUVs when applied in passive acoustic monitoring. This paper presents the acoustic observation application of the Petrel acoustic AUV in marine monitoring. The layout design of a Petrel acoustic AUV and acoustic sensor integration are described in detail, and the self-noise characteristics of Petrel acoustic AUVs are evaluated by simulation and testing. The results showed that the self-noise level of Petrel acoustic AUVs is effectively controlled with its optimized design, and the maximum noise of the propulsion system is only 75 dB in the low-frequency band. Therefore, the Petrel acoustic AUV can be used as an ideal acoustic observation platform to carry out diverse observation tasks. Finally, a solution of fixed-depth motion is proposed to address the problem that frequent attitude adjustment affects the quality of acoustic data in fixed-depth navigation. According to a sea trial in the South China Sea, the method can significantly reduce the attitude adjustment frequency and, thus, provide an ideal environment for acoustic observation. This method also applies to other underwater mobile observation platforms. This study provides a reference for the acoustic integration design of underwater equipment such as long-range AUVs or hybrid-driven underwater gliders.
    Type of Medium: Online Resource
    ISSN: 1070-6631 , 1089-7666
    URL: Article
    DOI: 10.1063/5.0083951
    Language: English
    Publisher: AIP Publishing
    Publication Date: 2022
    detail.hit.zdb_id: 1472743-2
    detail.hit.zdb_id: 241528-8
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  • 2
    Online Resource
    Online Resource
    Numerical study of period multiplication and chaotic phenomena in an atmospheric radio-frequency discharge
    AIP Publishing ; 2010
    In:  Physics of Plasmas Vol. 17, No. 4 ( 2010-04-01)
    Details
    In: Physics of Plasmas, AIP Publishing, Vol. 17, No. 4 ( 2010-04-01)
    Abstract: In this paper, a computational study of period multiplication and chaotic behavior of radio-frequency (rf) dielectric-barrier discharge (DBD) in atmospheric argon using an one-dimension fluid model was reported. These complex nonlinear behaviors are closely associated with the current-voltage characteristics of rf DBD, and mainly occur in γ-mode of rf DBD with relatively larger negative differential conductivity. With varying the discharge parameter rf DBD in γ-mode undergoes a transition from single-period discharge to chaos through period doubling bifurcation. When period multiplication and chaos take place, the sheath electric field bifurcates to cause the regular or irregular fluctuation in sheath thickness, consequently resulting in the period multiplication or chaotic behavior of the discharge current density. The spatial characteristics of rf period multiplication or chaotic discharges are also investigated.
    Type of Medium: Online Resource
    ISSN: 1070-664X , 1089-7674
    URL: Article
    DOI: 10.1063/1.3392291
    Language: English
    Publisher: AIP Publishing
    Publication Date: 2010
    detail.hit.zdb_id: 1472746-8
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  • 3
    Online Resource
    Online Resource
    Radial behavior of the pulsed dielectric-barrier discharge in atmospheric helium
    AIP Publishing ; 2012
    In:  Physics of Plasmas Vol. 19, No. 12 ( 2012-12-01)
    Details
    In: Physics of Plasmas, AIP Publishing, Vol. 19, No. 12 ( 2012-12-01)
    Abstract: The radial behavior of the pulsed dielectric-barrier discharge in atmospheric helium is studied by a two-dimensional, self-consistent fluid model. It is found that the two discharges ignited during one voltage pulse can possess different radial behaviors, and the discharge behavior is determined by the electron density distribution right before this discharge is ignited. The electron density distributions before the two discharges start depend on the time intervals between two discharges and their previous discharge processes. If the electron density distribution is radially uniform at the end of the previous discharge, the shorter the time interval between two discharges is, the more uniform the electron density distribution before the next discharge is, and thus the more homogenous the subsequent discharge becomes. In pulsed discharge, the time intervals between two discharges are mainly determined by the duration and repetition frequency of applied voltage pulse. These results are further supported by the investigation of the discharge behaviors under different pulse durations and repetition frequencies.
    Type of Medium: Online Resource
    ISSN: 1070-664X , 1089-7674
    URL: Article
    DOI: 10.1063/1.4773044
    Language: English
    Publisher: AIP Publishing
    Publication Date: 2012
    detail.hit.zdb_id: 1472746-8
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  • 4
    Online Resource
    Online Resource
    Simulation study of one-dimensional self-organized pattern in an atmospheric-pressure dielectric barrier discharge
    AIP Publishing ; 2015
    In:  Physics of Plasmas Vol. 22, No. 4 ( 2015-04-01)
    Details
    In: Physics of Plasmas, AIP Publishing, Vol. 22, No. 4 ( 2015-04-01)
    Abstract: A two-dimensional fluid model is developed to simulate the one-dimensional self-organized patterns in an atmospheric-pressure dielectric barrier discharge (DBD) driven by sinusoidal voltage in argon. Under certain conditions, by changing applied voltage amplitude, the transversely uniform discharge can evolve into the patterned discharge and the varied self-organized patterned discharges with different numbers and arrangements of discharge channels can be observed. Similar to the uniform atmospheric-pressure DBD, the patterned discharge mode is found to undergo a transition from Townsend regime, sub-glow regime to glow regime with increasing applied voltage amplitude. In the different regimes, charged particles and electric field display different dynamical behaviors. If the voltage amplitude is increased over a certain value, the discharge enters an asymmetric patterned discharge mode, and then transforms into the spatially chaotic state with out-of-order discharge channels. The reason for forming the one-dimensional self-organized pattern is mainly due to the so-called activation-inhibition effect resulting from the local high electron density region appearing in discharge space. Electrode arrangement is the reason that induces local high electron density.
    Type of Medium: Online Resource
    ISSN: 1070-664X , 1089-7674
    URL: Article
    DOI: 10.1063/1.4919623
    Language: English
    Publisher: AIP Publishing
    Publication Date: 2015
    detail.hit.zdb_id: 1472746-8
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  • 5
    Online Resource
    Online Resource
    Two-dimensional simulation of discharge channels in atmospheric-pressure single dielectric barrier discharges
    AIP Publishing ; 2015
    In:  Physics of Plasmas Vol. 22, No. 11 ( 2015-11-01)
    Details
    In: Physics of Plasmas, AIP Publishing, Vol. 22, No. 11 ( 2015-11-01)
    Abstract: A two-dimensional fluid model is developed to study the filaments (or discharge channels) in atmospheric-pressure discharge with one plate electrode covered by a dielectric layer. Under certain discharge parameters, one or more stable filaments with wide radii could be regularly arranged in the discharge space. Different from the short-lived randomly distributed microdischarges, this stable and thick filament can carry more current and have longer lifetime. Because only one electrode is covered by a dielectric layer in the simulation, the formed discharge channel extends outwards near the dielectric layer and shrinks inwards near the naked electrode, agreeing with the experimental results. In this paper, the evolution of channel is studied, and its behavior is like a streamer or an ionization wave, but the propagation distance is short. The discharge parameters such as voltage amplitude, electrode width, and N2 impurities content could significantly influence the number of discharge channel, which is discussed in the paper.
    Type of Medium: Online Resource
    ISSN: 1070-664X , 1089-7674
    URL: Article
    DOI: 10.1063/1.4935902
    Language: English
    Publisher: AIP Publishing
    Publication Date: 2015
    detail.hit.zdb_id: 1472746-8
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  • 6
    Online Resource
    Online Resource
    Characterization of complementary patterned metallic membranes produced simultaneously by a dual fabrication process
    AIP Publishing ; 2010
    In:  Applied Physics Letters Vol. 97, No. 19 ( 2010-11-08)
    Details
    In: Applied Physics Letters, AIP Publishing, Vol. 97, No. 19 ( 2010-11-08)
    Abstract: An efficient technique is developed to fabricate optically thin metallic films with subwavelength patterns and their complements simultaneously. By comparing the spectra of the complementary films, we show that Babinet’s principle nearly holds for these structures in the optical domain. Rigorous full-wave simulations are employed to verify the experimental observations. It is further demonstrated that a discrete-dipole approximation can qualitatively describe the spectral dependence of the metallic membranes on the geometry of the constituent particles as well as the illuminating polarization.
    Type of Medium: Online Resource
    ISSN: 0003-6951 , 1077-3118
    URL: Article
    DOI: 10.1063/1.3504664
    RVK:
    UA 1000
    Language: English
    Publisher: AIP Publishing
    Publication Date: 2010
    detail.hit.zdb_id: 211245-0
    detail.hit.zdb_id: 1469436-0
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  • 7
    Online Resource
    Online Resource
    Period-two discharge characteristics in argon atmospheric dielectric-barrier discharges
    AIP Publishing ; 2009
    In:  Physics of Plasmas Vol. 16, No. 6 ( 2009-06-01)
    Details
    In: Physics of Plasmas, AIP Publishing, Vol. 16, No. 6 ( 2009-06-01)
    Abstract: Period multiplication and chaos behaviors in atmospheric glow discharges are important to understand atmospheric glow plasma stability and to optimize its applications. In this paper, we study the period-two discharge characteristics in argon atmospheric dielectric-barrier discharges using a one-dimension fluid model. Under certain conditions, period-two discharges can occur at different excitation frequencies and exhibit different current and voltage behaviors. When the discharge current becomes highly symmetrical the period-two discharge can reach to a steady state, which sustains over a broad frequency range. At the sufficiently high excitation frequency, the period-two discharge in atmospheric argon shows noticeably different behaviors from the discharges generated at kilohertz frequency. The spatial characteristics of period-two discharge as well as the influence of driving frequency on period-two discharge behaviors are also investigated.
    Type of Medium: Online Resource
    ISSN: 1070-664X , 1089-7674
    URL: Article
    DOI: 10.1063/1.3155447
    Language: English
    Publisher: AIP Publishing
    Publication Date: 2009
    detail.hit.zdb_id: 1472746-8
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  • 8
    Online Resource
    Online Resource
    Two-dimensional numerical study of a period-two dielectric-barrier discharge in atmospheric argon
    AIP Publishing ; 2012
    In:  Physics of Plasmas Vol. 19, No. 4 ( 2012-04-01)
    Details
    In: Physics of Plasmas, AIP Publishing, Vol. 19, No. 4 ( 2012-04-01)
    Abstract: A two-dimensional fluid simulation is performed on an atmospheric dielectric barrier discharge (DBD) in pure argon to explore the formation mechanism and spatiotemporal evolution of period-two DBD at atmospheric pressure. The results show that the formation of the period-two discharge is directly correlated to the spatial distribution of electron density. It is found that when under certain conditions, a local high electron density region occurs before a new discharge is ignited, and the discharge current varies in magnitude depending on whereabouts of the local high electron density region. When the local high electron density region appears near the momentary anode, it barely affects the discharge current. In contrast, when the high electron density region appears in the vicinity of the cathode, it reduces the discharge current greatly, since it restrains the growth of the electric field. The local high electron density region disappears completely before the two voltage cycles end, and thus the discharge exhibits the appearance of period-two state. The radial current and electron density distributions at different times indicate that different discharge events within one oscillation period of period-two discharge possess different radial behaviors. The causes for these radial behaviors are further analyzed and discussed in this paper.
    Type of Medium: Online Resource
    ISSN: 1070-664X , 1089-7674
    URL: Article
    DOI: 10.1063/1.3700176
    Language: English
    Publisher: AIP Publishing
    Publication Date: 2012
    detail.hit.zdb_id: 1472746-8
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  • 9
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    Online Resource
    Beam optics analysis on magnetic-state-selected atomic clocks with optical detection
    AIP Publishing ; 2022
    In:  Journal of Applied Physics Vol. 131, No. 11 ( 2022-03-21)
    Details
    In: Journal of Applied Physics, AIP Publishing, Vol. 131, No. 11 ( 2022-03-21)
    Abstract: In traditional cesium beam clocks, cesium atoms are deflected by strong inhomogeneous magnetic fields. The distribution of the detectable atoms, which is critical to the short-term frequency stability, is hard to describe with analytical functions. In this paper, we numerically analyze the beam optics performance of cesium beam tubes based on the magnetic-state-selected and fluorescence detection scheme. To accurately model the cesium beam tube, we apply the Monte Carlo sampling directly inside the collimator. The finite element method is also applied to model the magnetic field. Upon the high dimensional distribution space, two key parameters are selected as indicators of the short-term performance of the cesium beam tube, the effective velocity distribution, and the normalized density difference of atoms in |F=3,mF=0⟩ and |F=4,mF=0⟩. The influence of the configuration of the collimator is analyzed. Experiments are carried out with two manufactured beam tubes. The results show good agreement with the simulation model. We also discuss limitations of the simulation method when applied to designing cesium beam tubes.
    Type of Medium: Online Resource
    ISSN: 0021-8979 , 1089-7550
    URL: Article
    DOI: 10.1063/5.0083473
    Language: English
    Publisher: AIP Publishing
    Publication Date: 2022
    detail.hit.zdb_id: 220641-9
    detail.hit.zdb_id: 3112-4
    detail.hit.zdb_id: 1476463-5
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  • 10
    Online Resource
    Online Resource
    Improving the short-term frequency stability of a magnetic-state-selected cesium beam clock with optical detection
    AIP Publishing ; 2021
    In:  Review of Scientific Instruments Vol. 92, No. 7 ( 2021-07-01)
    Details
    In: Review of Scientific Instruments, AIP Publishing, Vol. 92, No. 7 ( 2021-07-01)
    Abstract: The microwave spectrum line shape and the signal-to-noise ratio of a compact optically detected magnetic-state-selection cesium beam clock are analyzed in this paper. As the noise analysis shows, the performance is related to the atomic utilization ratio and locking parameters when the laser frequency noise is the dominant noise source. Methods are adopted for realizing better short-term frequency stability of the clock, including using a highly efficient state-selection cesium beam tube, optimizing the locking parameters, and stabilizing the microwave power to maximize the error signal. After optimization, the signal-to-noise ratio of the clock reaches 7.0 × 103 in a bandwidth of 1 Hz and the clock demonstrates a short-term stability of 4.1 × 10−12 τ−1/2. The five-day Allan standard deviation reaches 7.7 × 10−15.
    Type of Medium: Online Resource
    ISSN: 0034-6748 , 1089-7623
    URL: Article
    DOI: 10.1063/5.0046575
    Language: English
    Publisher: AIP Publishing
    Publication Date: 2021
    detail.hit.zdb_id: 209865-9
    detail.hit.zdb_id: 1472905-2
    SSG: 11
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