Journal articles: 'Vertical array'

1

Ma, Qiang, Chengda Pan, Yingxian Xue, Zhiyun Fang, Shiyu Zhang, Botao Wu, and E. Wu. "Plasmon Enhanced Second Harmonic Generation from ZnO Nanofilms on Vertical Au Nanorod Arrays." Nanomaterials 11, no. 10 (October 2, 2021): 2597. http://dx.doi.org/10.3390/nano11102597.

Full text

Abstract:

Vertically aligned gold nanorod arrays have attracted much attention for their fascinating optical properties. Different from longitudinal surface plasmon wavelength (LSPW) and edge-to-edge spacing of gold nanorods, the role of gold nanorod diameter in plasmonic enhancement ability of vertical gold nanorod arrays has rarely been explored. In this work, we selected gold nanorods with similar LSPW but two different diameters (22 and 41 nm), the optical properties of which are dominated by absorption and scattering cross sections, respectively. The vertically aligned arrays of these gold nanorods formed by evaporation self-assembly are coupled with nonlinear ZnO nanocrystal films spin-coated on their surfaces. It was found that the gold nanorod array with a larger diameter can enhance the second harmonic generation (SHG) of ZnO nanofilm by a factor of 27.0, while it is about 7.3 for the smaller gold nanorod array. Theoretical simulations indicate that such stronger enhancement of the larger vertical gold nanorod array compared with the smaller one is due to its stronger scattering ability and greater extent of near-field enhancement at SHG fundamental wavelength. Our work shows that the diameter of gold nanorods is also an important factor to be considered in realizing strong plasmon enhancement of vertically aligned gold nanorod arrays.

APA, Harvard, Vancouver, ISO, and other styles

2

Selvakumar, A., and K. Najafi. "Vertical comb array microactuators." Journal of Microelectromechanical Systems 12, no. 4 (August 2003): 440–49. http://dx.doi.org/10.1109/jmems.2003.811752.

Full text

APA, Harvard, Vancouver, ISO, and other styles

3

Wu, Jinping, Wenxiao Qiao, Xiaohua Che, Xiaodong Ju, Junqiang Lu, and Wenhe Wu. "Experimental study on the radiation characteristics of downhole acoustic phased combined arc array transmitter." GEOPHYSICS 78, no. 1 (January 1, 2013): D1—D9. http://dx.doi.org/10.1190/geo2012-0114.1.

Full text

Abstract:

A new kind of acoustic phased combined arc array transmitter with controllable directivity presented can be used in 3D acoustic image logging. The phased combined arc array is composed of numerous phased arc arrays placed equally along an axis. Each phased arc array contains several array elements arranged around a circumference. The phased combined arc array is considered as the combination of phased arc arrays and linear phased arrays. A directional radiation acoustic beam in the space is generated by simultaneously controlling the phase delay of excitation signals exerted on array elements located in the circumferential and axial directions. To investigate the radiation characteristics, an acoustic transmitter comprising four eight-element phased arc arrays was assembled to conduct physical simulation experiments in a water tank. Experimental results show that the main lobe width of the horizontal radiation energy narrows significantly by exerting phase delayed excitation signals on array elements of phased arc arrays. Adjusting the delay time of excitation signals applied on neighboring-phased arc arrays allows the main lobe direction of the vertical radiation energy to be steered and facilitates the change in the main lobe width of the vertical radiation energy. The phased combined arc array is characterized by controllable horizontal directivity, vertical directivity, and main lobe width of the radiated acoustic beam. More importantly, the acoustic phased combined arc array transmitter is applicable to 3D acoustic image logging, which is helpful in the enhancement of the reliability and accuracy of complex reservoir exploration.

APA, Harvard, Vancouver, ISO, and other styles

4

Liang, Yan, Zhou Meng, Yu Chen, Zemin Zhou, and Mo Chen. "Vertical Correlation and Array Gain Analysis for Vertical Line Array in Deep Water." Applied Sciences 10, no. 14 (July 8, 2020): 4709. http://dx.doi.org/10.3390/app10144709.

Full text

Abstract:

Array gain (AG) is significant in evaluating the detection performance of the vertical line array, which is directly determined by the correlation of signal and noise, respectively. In this paper, we analyze the vertical correlation for a 16-element vertical line array experimented in the deep ocean in 2016. The ray interference theory is utilized to interpret the mechanism of the vertical correlation of the sound field in different zones. In the direct-arrival zone, the direct rays and once-surface-reflected rays are two dominated components, whose arrival time difference for each element are nearly the same, and the vertical correlation is high. In the shadow zone, the sound field is mainly dominated by bottom-reflected rays and the vertical correlation decreases due to different grazing angles and arrival times of each ray. Different from the previous assumption of noise independence, the effect of noise correlation on the AG is analyzed through the measured marine environmental noise. Results indicate that the noise correlation coefficients in two zones are low but not 0. In the direct-arrival zone, AG is about 10 dB, very close to the ideal value of 10 log M . AG even exceeds it when NG is negative. Moreover, AG in the direct-arrival zone is higher than the one in the shadow zone.

APA, Harvard, Vancouver, ISO, and other styles

5

Afshari, Kioumars, Jonathan P. Stewart, and Jamison H. Steidl. "California Ground Motion Vertical Array Database." Earthquake Spectra 35, no. 4 (November 2019): 2003–15. http://dx.doi.org/10.1193/070218eqs170dp.

Full text

Abstract:

We present a data set of ground motion recordings and site information from vertical array sites in California. The recordings include two horizontal components of ground shaking at the ground surface level and from downhole sensors. The availability of both surface and downhole recordings at the same site facilitates direct observations of site response. The site data include measured shear-and compression-wave velocities, and, where available, geotechnical boring logs. We considered 39 vertical array sites in California and chose 21 for inclusion in the database on the basis of having at least four pairs of surface/downhole recordings. The recordings and site data are presented in a data repository, which is accessible at the DesignSafe platform (DOI: 10.17603/146DS2N680). The original digital accelerograms are processed in a manner consistent with NGA-West2 protocols. In this paper, this data set is compared to a similar but larger data set from Japanese vertical arrays compiled by others.

APA, Harvard, Vancouver, ISO, and other styles

6

Nakamura, Hisatsugu. "Vertical array type speaker system." Journal of the Acoustical Society of America 102, no. 3 (September 1997): 1277. http://dx.doi.org/10.1121/1.419987.

Full text

APA, Harvard, Vancouver, ISO, and other styles

7

Roderick, W. I., and W. A. Von Winkle. "Expendable virtual vertical sensing array." Journal of the Acoustical Society of America 92, no. 3 (September 1992): 1794. http://dx.doi.org/10.1121/1.403891.

Full text

APA, Harvard, Vancouver, ISO, and other styles

8

Worcester, Peter F., Matthew A. Dzieciuch, Lloyd L. Green, David D. Horwitt, Jacques C. Lemire, Scott D. Carey, and Matthew Norenberg. "Distributed vertical line array receiver." Journal of the Acoustical Society of America 129, no. 4 (April 2011): 2644. http://dx.doi.org/10.1121/1.3588810.

Full text

APA, Harvard, Vancouver, ISO, and other styles

9

Ahnood, Arman, Hang Zhou, Qing Dai, Yuri Vygranenko, Yuji Suzuki, MR Esmaeili-Rad, Gehan Amaratunga, and Arokia Nathan. "Vertical CNT-Si Photodiode Array." Nano Letters 13, no. 9 (August 7, 2013): 4131–36. http://dx.doi.org/10.1021/nl401636v.

Full text

APA, Harvard, Vancouver, ISO, and other styles

10

Earley, Ray, and David Bradshaw. "4970697 Vertical marine seismic array." Deep Sea Research Part B. Oceanographic Literature Review 38, no. 6 (January 1991): 520. http://dx.doi.org/10.1016/s0198-0254(05)80166-9.

Full text

APA, Harvard, Vancouver, ISO, and other styles

11

He, Tao, Yukun Zhao, Xiaodong Zhang, Wenkui Lin, Kai Fu, Chi Sun, Fengfeng Shi, et al. "Solar-blind ultraviolet photodetector based on graphene/vertical Ga2O3 nanowire array heterojunction." Nanophotonics 7, no. 9 (August 28, 2018): 1557–62. http://dx.doi.org/10.1515/nanoph-2018-0061.

Full text

Abstract:

AbstractIn this paper, a solar-blind ultraviolet photodetector (PD) based on the graphene/vertical Ga2O3 nanowire array heterojunction was proposed and demonstrated. To the best of our knowledge, it is the first time that vertical Ga2O3 nanowire arrays have been realized. Ga2O3 nanowires were obtained by thermally oxidizing GaN nanowires grown by molecular beam epitaxy on n-doped Si substrate. Then, a monolayer graphene film was transferred to Ga2O3 nanowires to form the graphene/vertical Ga2O3 nanowire array heterojunction and transparent electrodes. The fabricated device exhibited a responsivity (R) of 0.185 A/W and rejection ratio (R258 nm/R365 nm) of 3×104 at the bias of −5 V. Moreover, the fast response times of this PD were 9 and 8 ms for the rise and decay times under 254 nm illumination, respectively, which are attributed to the unique properties of nanowire arrays and the graphene/vertical Ga2O3 nanowire array heterojunction structure.

APA, Harvard, Vancouver, ISO, and other styles

12

Darrh, Andréa, Christian Poppeliers, and Leiph Preston. "Azimuthally Dependent Seismic‐Wave Coherence at the Source Physics Experiment Large‐N Array." Bulletin of the Seismological Society of America 109, no. 5 (July 30, 2019): 1935–47. http://dx.doi.org/10.1785/0120180296.

Full text

Abstract:

Abstract We document azimuthally dependent seismic scattering at the Source Physics Experiment (SPE) using the large‐N array. The large‐N array recorded the seismic wavefield produced by the SPE‐5 buried chemical explosion, which occurred in April 2016 at the Nevada National Security Site, U.S.A. By selecting a subset of vertical‐component geophones from the large‐N array, we formed 10 linear arrays, with different nominal source–receiver azimuths as well as six 2D arrays. For each linear array, we evaluate wavefield coherency as a function of frequency and interstation distance. For both the P arrival and post‐P arrivals, the coherency is higher in the northeast propagation direction, which is consistent with the strike of the steeply dipping Boundary fault adjacent to the northwest side of the large‐N array. Conventional array analysis using a suite of 2D arrays suggests that the presence of the fault may help explain the azimuthal dependence of the seismic‐wave coherency for all wave types. This fault, which separates granite from alluvium, may be acting as a vertically oriented refractor and/or waveguide.

APA, Harvard, Vancouver, ISO, and other styles

13

HARRISON, BRIAN F. "BROADBAND MATCHED-FIELD LOCALIZATION PERFORMANCE IN UNCERTAIN ENVIRONMENTS USING A SHORT ARRAY." Journal of Computational Acoustics 09, no. 03 (September 2001): 957–72. http://dx.doi.org/10.1142/s0218396x01000863.

Full text

Abstract:

Typical applications of matched-field localization use low frequency signals received on large aperture vertical-arrays. However, small aperture arrays are much more practical for real-world systems and must be considered. Additionally, any practical localization algorithm must also be robust to environmental mismatch. In this paper, we present the broadband L∞-norm estimator for robust matched-field localization of mid-frequency signals (e.g., 800–4000 Hz) received on very short aperture vertical-arrays. Realistic simulation results are presented using broadband signals in the band of 1000–3000 Hz received on a 3 m vertical array which demonstrate the substantial performance gains in using the L∞-norm estimator over the asymptotically-optimal maximum a posteriori estimator and the conventional Bartlett processor. Experimental data results in an uncertain shallow-water environment using a 2.13 m vertical array in the band of 3000–4000 Hz are also presented.

APA, Harvard, Vancouver, ISO, and other styles

14

Martinez-Ojeda, Edgar, Francisco Javier Solorio Ordaz, and Mihir Sen. "Study of Vertical-Axis Wind Farm Layouts Using a 2D Actuator-Cylinder RANS Model." Journal of Energy 2022 (December 21, 2022): 1–10. http://dx.doi.org/10.1155/2022/7497795.

Full text

Abstract:

The actuator-cylinder RANS (Reynolds-averaged Navier-Stokes equations) model was used to study the performance of two different arrays of wind turbines. The staggered array proved to be more efficient than the fish-school array (grouped in pairs) in most directions; however, the fish-school array outperformed the conventional staggered array when the pairs of turbines were facing the wind. Increases in global power coefficient up to 16% were found when the wind speed was 8 ms-1 and up to 10% when the wind speed was 10 ms-1. Despite the fish-school array being slightly less efficient, this array yielded almost twice as much power density as the staggered array in almost all directions. The current methodology proves to be a fast tool for the estimation of vertical-axis wind turbine farms compared to full RANS simulations.

APA, Harvard, Vancouver, ISO, and other styles

15

Zhang, Ling, and Qiang Zhu. "An Array Design Method and Error Analysis for Terminal Trajectory Measurement." Applied Mechanics and Materials 687-691 (November 2014): 774–78. http://dx.doi.org/10.4028/www.scientific.net/amm.687-691.774.

Full text

Abstract:

This paper introduces the implement method of system ,direction finding array design, time delay estimation of terminal trajectory measurement system. To measure the elevation angle in a vertical plane, discusses the azimuth angle, elevation angle measurement method and error analysis of planar cross array, five element conical array, symmetrical three-dimensional four elements array. After simulation the paper pointed out the last two arrays are better for terminal trajectory measurement based short baseline array.

APA, Harvard, Vancouver, ISO, and other styles

16

Kim, Kangil, Jae Keun Lee, Seung Ju Han, and Sangmin Lee. "A Novel Top-Down Fabrication Process for Vertically-Stacked Silicon-Nanowire Array." Applied Sciences 10, no. 3 (February 8, 2020): 1146. http://dx.doi.org/10.3390/app10031146.

Full text

Abstract:

Silicon nanowires are widely used for sensing applications due to their outstanding mechanical, electrical, and optical properties. However, one of the major challenges involves introducing silicon-nanowire arrays to a specific layout location with reproducible and controllable dimensions. Indeed, for integration with microscale structures and circuits, a monolithic wafer-level process based on a top-down silicon-nanowire array fabrication method is essential. For sensors in various electromechanical and photoelectric applications, the need for silicon nanowires (as a functional building block) is increasing, and thus monolithic integration is highly required. In this paper, a novel top-down method for fabricating vertically-stacked silicon-nanowire arrays is presented. This method enables the fabrication of lateral silicon-nanowire arrays in a vertical direction, as well as the fabrication of an increased number of silicon nanowires on a finite dimension. The proposed fabrication method uses a number of processes: photolithography, deep reactive-ion etching, and wet oxidation. In applying the proposed method, a vertically-aligned silicon-nanowire array, in which a single layer consists of three vertical layers with 20 silicon nanowires, is fabricated and analyzed. The diamond-shaped cross-sectional dimension of a single silicon nanowire is approximately 300 nm in width and 20 μm in length. The developed method is expected to result in highly-sensitive, reproducible, and low-cost silicon-nanowire sensors for various biomedical applications.

APA, Harvard, Vancouver, ISO, and other styles

17

Dikopoltsev, Alex, Tristan H. Harder, Eran Lustig, Oleg A. Egorov, Johannes Beierlein, Adriana Wolf, Yaakov Lumer, et al. "Topological insulator vertical-cavity laser array." Science 373, no. 6562 (September 24, 2021): 1514–17. http://dx.doi.org/10.1126/science.abj2232.

Full text

APA, Harvard, Vancouver, ISO, and other styles

18

Bennetts, Luke G., Malte A. Peter, and Fabien Montiel. "Localisation of Rayleigh–Bloch waves and damping of resonant loads on arrays of vertical cylinders." Journal of Fluid Mechanics 813 (January 20, 2017): 508–27. http://dx.doi.org/10.1017/jfm.2016.855.

Full text

Abstract:

Linear potential-flow theory is used to study loads imposed on finite line arrays of rigid, bottom-mounted, surface-piercing, vertical cylinders by surface water waves. Perturbations in the cylinder locations are shown to damp the resonant loads experienced by the unperturbed array. A relationship is established between the damping and the phenomenon of Anderson localisation. Specifically, the Rayleigh–Bloch waves responsible for the resonant loads are shown to attenuate along the array when perturbations are introduced, resulting in localisation when the attenuation rate is sufficiently large with respect to the array length. Further, an efficient solution method for line arrays is introduced that captures the Rayleigh–Bloch wave modes supported by unperturbed arrays from the scattering characteristics of an individual cylinder.

APA, Harvard, Vancouver, ISO, and other styles

19

Aldridge, David F. "Statistically perturbed geophone array responses." GEOPHYSICS 54, no. 10 (October 1989): 1306–17. http://dx.doi.org/10.1190/1.1442590.

Full text

Abstract:

Seismic‐receiver arrays implemented under typical field conditions are subject to a variety of perturbing influences. The array responses that are actually achieved differ, perhaps substantially, from the nominal response associated with ideal conditions (precise positioning, vertical plants, identical geophones, perfect ground coupling, etc.). Variations in receiver array response may degrade the effectiveness of multichannel processing and analysis schemes that rely upon channel‐to‐channel waveform constancy. In effect, array‐response variation is a form of noise added to recorded waveforms and is thus potentially harmful. A rigorous physical treatment of the response of a geophone array to incident plane‐wave elastic radiation forms the point of departure for assessing the importance of response perturbations. The hard‐wired multiple seismometer group, long transmission line, and recording‐system input impedance are considered an electromechanical system. An individual geophone may have arbitrarily specified position and axial orientation and is modeled as a ground‐motion transducer that incorporates, to first order, the effect of compliant coupling to the earth. Elastic waves (of either vibratory mode) can be incident from any direction. This generality built into the mathematical description of receiver‐array response allows numerous array types (including those designed to record shear waves) to be analyzed. All parameters that determine the response value are then subjected to controlled random perturbations in order to evaluate the statistical variability of the complex valued array‐response function. Transformation of the perturbed responses to the time domain indicates the extent of waveform variability induced by geophone‐array diversity. Computational studies indicate that, for vertical or near‐vertical plane P‐wave incidence, reasonable variations in the controlling parameters do not reduce waveform coherence by any major amount. Peak times of reflection signal recorded on well planted geophone arrays typically vary by up to 4 ms. As the angle of incidence increases or the quality of the field‐array implementation degrades, the wavelets exhibit increasing amplitude loss, wave‐shape alteration, and incoherence that may affect an interpretation.

APA, Harvard, Vancouver, ISO, and other styles

20

Konispoliatis, Dimitrios N., Spyridon A. Mavrakos, and Georgios M. Katsaounis. "Theoretical Evaluation of the Hydrodynamic Characteristics of Arrays of Vertical Axisymmetric Floaters of Arbitrary Shape in front of a Vertical Breakwater." Journal of Marine Science and Engineering 8, no. 1 (January 20, 2020): 62. http://dx.doi.org/10.3390/jmse8010062.

Full text

Abstract:

The present paper deals with the analytical evaluation of the hydrodynamic characteristics of an array of vertical axisymmetric bodies of arbitrary shape, placed in front of a reflecting vertical breakwater, which can be conceived as floaters for wave power absorption. At the first part of the paper, the hydrodynamic interactions between the floaters and the adjacent breakwater are exactly taken into account using the method of images, whereas, the interaction phenomena between the floaters of the array are estimated using the multiple scattering approach. For the solution of the problem, the flow field around each floater of the array is subdivided into ring-shaped fluid regions, in each of which axisymmetric eigenfunction expansions for the velocity potential are made. In the second part of the paper, extensive theoretical results are presented concerning the exciting wave forces and the hydrodynamic coefficients for various arrays’ arrangements of axisymmetric floaters. The aim of the study is to show parametrically the effect that the vertical breakwater has on the hydrodynamic characteristics of each particular floater.

APA, Harvard, Vancouver, ISO, and other styles

21

Dosso, Stan E., Barbara J. Sotirin, and Vincent K. McDonald. "Array element localization for vertical hydrophone arrays in the Arctic ocean." Journal of the Acoustical Society of America 102, no. 5 (November 1997): 3100. http://dx.doi.org/10.1121/1.420503.

Full text

APA, Harvard, Vancouver, ISO, and other styles

22

Levin, Franklyn K. "The effect of geophone arrays on random noise." GEOPHYSICS 54, no. 11 (November 1989): 1466–73. http://dx.doi.org/10.1190/1.1442610.

Full text

Abstract:

For spatially random noise consisting of plane surface waves arriving at a geophone from all directions with equal probability, I compute the noise‐to‐signal ratio (N/S) as a function of the ratio of geophone spacing Δ to noise wavelength λ for linear arrays of 12, 24, 36, and 72 vertical and horizontal geophones. For arrays of M vertical geophones, deviation of N/S from that for pure random noise, [Formula: see text] is marked. As Δ/λ increases, N/S decreases, attaining [Formula: see text] for a value of Δ/λ that defines a coherence distance. As Δ/λ increases beyond the coherence distance, N/S continues to decrease slightly, only to increase again as Δ/λ approaches unity. For linear arrays of 12 to 72 vertical geophones, Δ/λ at the coherence distance is nearly independent of M and is about 0.32. The value of Δ/λ for which N/S = 0.5 changes with M but L/λ, L being the array length defined as MΔ, is independent of M. Introducing a random 14 percent variation into the sensitivities of the individual geophones has a small influence on the coherence distance and the N/S = 0.5 point when the N/S curves for 50 arrays are summed. Introducing a random 14 percent variation into the spatial coordinates of the geophones changes the coherence distance and 0.5 point only slightly but reduces the amount by which N/S fails below [Formula: see text] For arrays of horizontal geophones, there are two N/S curves depending upon whether the horizontal motion is in the plane of incidence of the signal (SV waves) or perpendicular to the plane of incidence (SH waves). Due to the superdirectivity of the array, N/S for SV waves incident on an SV‐wave geophone array is very small for values of Δ/λ greater than about 0.1. The N/S curves for SH waves incident on an SV‐wave array resemble those for the arrays of vertical geophones. Again there is a coherence distance, but the Δ/λ value is twice that for the vertical geophones, indicating the geophones should be separated by about two‐thirds of a wavelength.

APA, Harvard, Vancouver, ISO, and other styles

23

Hsu, Kai, and Shu‐Kong Chang. "Multiple‐shot processing of array sonic waveforms." GEOPHYSICS 52, no. 10 (October 1987): 1376–90. http://dx.doi.org/10.1190/1.1442250.

Full text

Abstract:

Signal processing techniques are needed to estimate the slownesses (inverses of velocities) of compressional, shear, and Stoneley waves from array sonic waveforms recorded by array sonic tools. Existing processing techniques process entire array waveforms, assuming that each wave component has linear moveout (a constant velocity) across the array. The results show poor vertical resolution if the formation spanned by the array aperture is not homogeneous. Multiple‐shot processing is a technique to improve the vertical resolution of slowness logs. The algorithm incorporates redundant information from the multiplicity of overlapping tool locations. Specifically, the method includes four steps: (1) subarrays are selected from full arrays associated with shots from successive sources; (2) subarray waveforms are processed using the semblance statistic; (3) the semblance statistic is projected onto the slowness axis; and (4) the projected semblances of all selected subarrays are combined and the slownesses of the wave components are estimated from the combined statistic. The technique improves the vertical resolution of slowness logs because the subarrays are shorter than the full array. It also increases the accuracy of estimates of slowness because more data are used in the processing. This procedure is applicable to common‐shot subarrays as well as to common‐receiver subarrays. Combining common‐shot and common‐receiver results provides two additional advantages, namely, borehole compensation and measurement enhancement.

APA, Harvard, Vancouver, ISO, and other styles

24

CHANG-HASNAIN, C. J., Y. A. WU, L. E. ENG, and G. S. LI. "VERTICAL CAVITY SURFACE EMITTING LASER ARRAYS FOR WAVELENGTH DIVISION MULTIPLEXING APPLICATIONS." International Journal of High Speed Electronics and Systems 05, no. 04 (December 1994): 569–92. http://dx.doi.org/10.1142/s0129156494000231.

Full text

Abstract:

The capability to fabricate two-dimensional (2D) semiconductor diode laser array is one of the most important steps towards making wafer-scale low-cost lasers. The recent emergence of vertical cavity surface emitting laser (VCSEL) facilitates the fabrication of such large 2D arrays. In this paper, we review the recent progress on a novel largeaperture single-mode VCSEL and a 2D multiple-wavelength VCSEL array for ultra-high bandwidth applications. We demonstrate a passive antiguide region (PAR) VCSEL which emits a stable single mode with very low threshold, a large aperture, and a fixed polarization. We also demonstrate multi-wavelength VCSEL arrays with repeatable wavelength spans over 20 nm, grown by Molecular Beam Epitaxy. The wavelength shift is achieved by varying the GaAs growth rate across the wafer using a patterned backing wafer to induce a temperature profile. Such multiple wavelength laser arrays are promising for ultrahigh bandwidth optical transmission and switching systems using wavelength division multiplexing (WDM).

APA, Harvard, Vancouver, ISO, and other styles

25

Putiška, René, Ivan Dostál, and David Kušnirák. "Determination of dipping contacts using electrical resistivity tomography." Contributions to Geophysics and Geodesy 42, no. 2 (January 1, 2012): 161–80. http://dx.doi.org/10.2478/v10126-012-0007-6.

Full text

Abstract:

Determination of dipping contacts using electrical resistivity tomographyGenerally, all electrode arrays are able to delineate the contact of two lithostratigraphic units especially with very high resistivity contrast. However, the image resolution for the location of vertical and dipping structures is different. The responses of dipole-dipole (DD), Wenner alpha (WA), Schlumberger (SCH) and combined pole-dipole (PD) arrays have been computed using the finite difference method. Comparison of the responses indicates that: (1) The dipole-dipole array usually gives the best resolution and is the most detailed method especially for the detection of vertical structures. This array has shown the best resolution to recognize the geometrical characterisation of the fault. (2) The pole-dipole has shown the second best result in our test. The PD is an effective method for detection of vertical structures with a high depth range, but the deepest parts are deformed. (3) Wenner alpha shows a low resolution, inconvenient for detailed investigation of dip structures. (4) The Schlumberger array gives a good and sharp resolution to assess the contact between two lithological units but gives poor result for imaging geometry of dipping contact.

APA, Harvard, Vancouver, ISO, and other styles

26

Booth, N. O., R. Judd, and H. Bucker. "Measurement of vertical noise directionality with a mixed-polarity vertical array." IEEE Journal of Oceanic Engineering 28, no. 3 (July 2003): 537–43. http://dx.doi.org/10.1109/joe.2003.816674.

Full text

APA, Harvard, Vancouver, ISO, and other styles

27

Luo, Win-Jet, C. Bambang Dwi Kuncoro, Pratikto, and Yean-Der Kuan. "Single-Layer Transmitter Array Coil Pattern Evaluation toward a Uniform Vertical Magnetic Field Distribution." Energies 12, no. 21 (October 31, 2019): 4157. http://dx.doi.org/10.3390/en12214157.

Full text

Abstract:

A uniform magnetic field distribution is a critical aspect in the transmitter array coil design process for achieving a homogenous vertical magnetic field distribution. The free position and orientation features can thus be implemented in the wireless power charging system. This paper presents vertical magnetic field distribution generated by a single-layer circular flat spiral air core transmitter array coil model analysis and evaluation using a numerical analysis method. This method is developed based on the off-symmetry axis magnetic field distribution due to a circular current loop derived from the Biot-Savart law. The proposed evaluation criteria are used to obtain the vertical magnetic field distribution characteristic of the evaluated array coil model. The vertical magnetic field distribution of several circular flat spiral air core coils, in both single and array coil models with different coil geometries were investigated to obtain the relation between the coil parameters and the distance between the adjoining coil centers to generate uniform vertical magnetic field distribution. A case study was also conducted to analyze and evaluate several array coil model patterns (1 × 2 array coil, 1 × 3 array coil, 2 × 2 array coil, 2 × 3 array coil) to meet uniform vertical magnetic field distribution. The array coil model is composed of an identical single circular flat spiral air-core coil. Every single coil has inner coil diameter (Di), outer coil diameter (Do), wire diameter (W), pitch (P) and a number of turns (N) at 25 mm, 47.8 mm, 0.643 mm, 0.03 mm, 17 respectively. The study and evaluation of several array coil pattern models show that the distance between the adjoining coil centers should be defined close to the half of coil outer diameter (1/2Do) to generate close to uniform vertical magnetic field distribution. The vertical magnetic field distribution average and magnetic field effective transmitting areas array coil model with the given coil parameters changing as the effect in variation in distances between the adjoining coil centers.

APA, Harvard, Vancouver, ISO, and other styles

28

Berman, David H. "Sound‐speed profiles from vertical array data." Journal of the Acoustical Society of America 93, no. 4 (April 1993): 2375. http://dx.doi.org/10.1121/1.406132.

Full text

APA, Harvard, Vancouver, ISO, and other styles

29

Yoshida, Kunikazu, and Tsutomu Sasatani. "Seismic vertical array analysis for phase decomposition." Geophysical Journal International 174, no. 2 (August 2008): 707–18. http://dx.doi.org/10.1111/j.1365-246x.2008.03825.x.

Full text

APA, Harvard, Vancouver, ISO, and other styles

30

Chiba, Kohei, Akinobu Yoshida, Katsuhiro Tomioka, and Junichi Motohisa. "Vertical InGaAs Nanowire Array Photodiodes on Si." ACS Photonics 6, no. 2 (February 2019): 260–64. http://dx.doi.org/10.1021/acsphotonics.8b01089.

Full text

APA, Harvard, Vancouver, ISO, and other styles

31

Ruehle, William H. "Directional long array for logging vertical boundaries." Journal of the Acoustical Society of America 78, no. 3 (September 1985): 1152. http://dx.doi.org/10.1121/1.392970.

Full text

APA, Harvard, Vancouver, ISO, and other styles

32

Au, Whitlow W. L., Marc O. Lammers, Adam A. Pack, and Louis Herman. "Vertical array measurements of humpback whale songs." Journal of the Acoustical Society of America 115, no. 5 (May 2004): 2520–21. http://dx.doi.org/10.1121/1.4783263.

Full text

APA, Harvard, Vancouver, ISO, and other styles

33

Molyneaux, D. A., and A. H. Qureshi. "Vertical field quadrature phased array coil system." IEEE Transactions on Magnetics 32, no. 5 (1996): 5124–26. http://dx.doi.org/10.1109/20.539511.

Full text

APA, Harvard, Vancouver, ISO, and other styles

34

Lai, Elaine, Woong Kim, and Peidong Yang. "Vertical nanowire array-based light emitting diodes." Nano Research 1, no. 2 (July 31, 2008): 123–28. http://dx.doi.org/10.1007/s12274-008-8017-4.

Full text

APA, Harvard, Vancouver, ISO, and other styles

35

Marzetta, Thomas L., Marion Orton, Alfred Krampe, Lucian K. Johnston, and Paul C. Wuenschel. "A hydrophone vertical seismic profiling experiment." GEOPHYSICS 53, no. 11 (November 1988): 1437–44. http://dx.doi.org/10.1190/1.1442423.

Full text

Abstract:

To reduce the cost of VSP data acquisition, it is necessary to record the VSP signal from a vertical array of geophones for a single operation of the source. Until a vertical array of clamped three‐component geophones is available, it seems logical to evaluate the capabilities of a vertical array of hydrophones, which is much easier to fabricate. It is well known that elastic waves in the solid couple to pressure waves in the borehole fluid. It is also well known that this coupling excites in the borehole fluid energy known as tube‐wave noise that dominates the borehole pressure signal after the first arrival. (The borehole acts as a waveguide.) In this paper we test the effectiveness of velocity filtering of the borehole pressure signal to attenuate the slowly propagating tube‐wave noise and enhance the faster propagating body‐wave signals. Our initial test satisfactorily extracted from the hydrophone array data a strong reflected event that was also observed in the conventional clamped geophone VSP taken in the same borehole. We were not as successful in recovering subsequent weaker reflected signals from the hydrophone data, because of the strong incoherent ambient tube‐wave noise. This incoherency resulted from instrumental limitations that allowed us to record, for each shot, only three of the twelve hydrophone channels available in the vertical array.

APA, Harvard, Vancouver, ISO, and other styles

36

Kokusho, Takaji, and Tomohiro Ishizawa. "Site Amplification during Strong Earthquakes Investigated by Vertical Array Records." Geosciences 11, no. 12 (December 14, 2021): 510. http://dx.doi.org/10.3390/geosciences11120510.

Full text

Abstract:

A number of vertical array records during eight destructive earthquakes in Japan are utilized, after discussing criteria for desirable requirements of vertical arrays, to formulate seismic amplification between ground surface and outcrop base for seismic zonation. A correlation between peak spectrum amplification and Vs (S-wave velocity) ratio (base Vs/surface Vs) was found to clearly improve by using Vs in an equivalent surface layer wherein predominant frequency or first peak is exerted, though the currently used average Vs in top 30 m is also meaningful, correlating positively with the amplification. We also found that soil nonlinearity during strong earthquakes has only a marginal effect even in soft soil sites on the amplification between surface and outcrop base except for ultimate soil liquefaction failure, while strong nonlinearity clearly appears in the vertical array amplification between surface and downhole base. Its theoretical basis has been explained by a simple study on a two-layered system in terms of radiation damping and strain-dependent equivalent nonlinearity.

APA, Harvard, Vancouver, ISO, and other styles

37

North, William, Nusrat Jahan, Pawel Strzebonski, and Kent D. Choquette. "Modal characteristics of coupled vertical cavity surface emitting laser diode arrays." Journal of Applied Physics 132, no. 17 (November 7, 2022): 173102. http://dx.doi.org/10.1063/5.0119912.

Full text

Abstract:

The modal characteristics of dual-element coupled vertical cavity surface emitting laser (VCSEL) arrays are analyzed numerically and experimentally. A photonic crystal pattern etched into the top mirror optically defines the two elements of the array that are independently electrically biased. Using a two-dimensional complex waveguide analysis, we incorporate the effects of varying temperature and electron plasma-induced index suppression arising from asymmetric injection. The simulations are compared to experimental characterization of output power, lasing spectra, and far-field beam profile as a function of the two independent injection currents. Three distinct operating regimes are identified for the arrays: single independent local mode; a region of two modes that are primarily localized into a specific cavity; and a region of two supermodes whose fields extend across both elements. This analysis provides a physical intuition for the behavior of the dual-element coupled VCSEL array across its full operating range for emerging applications.

APA, Harvard, Vancouver, ISO, and other styles

38

del Moral, A., E. Amat, J. Bausells, and F. Perez-Murano. "Benefits of using arrays of vertical nanowire FETs in integrated circuits to mitigate variability." Semiconductor Science and Technology 36, no. 12 (November 12, 2021): 125017. http://dx.doi.org/10.1088/1361-6641/ac3371.

Full text

Abstract:

Abstract We investigate the benefits of the use of arrays of vertical nanowire (vNW) field-effect transistors (FETs) to implement integrated circuits. By means of technology computer aided design and circuit simulations, the optimal dimensions of the vNWFETs are determined. Device and circuit variability levels have been investigated. The benefits of using array configurations are the decrease of the response time and a significant mitigation of the variability level as the number of the elements in the array increases.

APA, Harvard, Vancouver, ISO, and other styles

39

Harris, D. B., G. D'Spain, and A. Goldner. "Regional observation of a nuclear test from a vertical hydrophone array." Bulletin of the Seismological Society of America 84, no. 4 (August 1, 1994): 1148–53. http://dx.doi.org/10.1785/bssa0840041148.

Full text

Abstract:

Abstract In order to evaluate the potential of water-column vertical hydrophone arrays for the measurement of continental events at regional distances, ocean acoustic data bases were examined for arrivals from these types of events. In 1987, the nuclear test LOCKNEY (mb 5.7, 37.28°N 116.38°W) was observed in the deep-ocean water column at a range of 900 km by the Vertical Line Array (VLA) at 35° N 126° W. Although the hydrophone data were contaminated below 10 Hz by array suspension noise and ocean acoustic noise, adaptive array processing allows us to extract the P and T phases. The root-mean-square (rms) direct P-wave amplitude in the water column is 100.6 dB referenced to 1 μPa in the 4- to 8-Hz band in a 20-sec window, which suggests a detection threshold of mb 5.2 in a deep oceanic environment at this range for a single hydrophone. The arrival time of the T phase [i.e., the portion of seismic energy that has somehow coupled into, and propagated within, the deep ocean sound channel (Aki and Richards, 1980)] is consistent with a P-wave conversion at the continental margin, assuming a velocity of 6 km/sec from NTS to the continental margin and acoustic propagation at 1.5 km/sec in the water column from the continent to the array.

APA, Harvard, Vancouver, ISO, and other styles

40

Zhang, Quan, Guo-an Cheng, and Rui-ting Zheng. "The Internal Buckling Behavior Induced by Growth Self-restriction in Vertical Multi-walled Carbon Nanotube Arrays." MRS Advances 3, no. 45-46 (2018): 2815–23. http://dx.doi.org/10.1557/adv.2018.429.

Full text

Abstract:

ABSTRACTThe internal buckling is a common phenomenon in the as-grown carbon nanotube arrays. It makes the physical properties of carbon nanotube array in experiment lower than that in theory. In this work, we analyzed the formation and evolution mechanism of the internal buckling based on quasi-static compression model, which is different from collective effect of the van der Waals interactions. The self-restriction effect and the different growth rate of carbon nanotubes verify the possibility of the quasi-static compression model to explain the morphology evolution of vertical carbon nanotube arrays, especially the phenomenon of the quasi-straight and bent carbon nanotubes coexisted in the array. We generalized the Euler beam to wave-like beam and explained the mechanism of high-mode buckling combined with the van der Waals interaction. The calculated result about the link between compressive stress and strain confirms with the stage of collective buckling in the quasi-static compression test of carbon nanotube array. Preparation of well-organized carbon nanotube arrays was strong evidence verified the effect of self-restriction in experiment.

APA, Harvard, Vancouver, ISO, and other styles

41

CHO, Chomgun, Hee-Chun Song, and William S. Hodgkiss. "Robust source-range estimation using a vertical array and the array invariant." Journal of the Acoustical Society of America 138, no. 3 (September 2015): 1928. http://dx.doi.org/10.1121/1.4934071.

Full text

APA, Harvard, Vancouver, ISO, and other styles

42

Chen, Zhisheng, Renjun Song, Qiang Huo, Qirui Ren, Chenrui Zhang, Linan Li, and Feng Zhang. "Analysis of Leakage Current of HfO2/TaOx-Based 3-D Vertical Resistive Random Access Memory Array." Micromachines 12, no. 6 (May 26, 2021): 614. http://dx.doi.org/10.3390/mi12060614.

Full text

Abstract:

Three-dimensional vertical resistive random access memory (VRRAM) is proposed as a promising candidate for increasing resistive memory storage density, but the performance evaluation mechanism of 3-D VRRAM arrays is still not mature enough. The previous approach to evaluating the performance of 3-D VRRAM was based on the write and read margin. However, the leakage current (LC) of the 3-D VRRAM array is a concern as well. Excess leakage currents not only reduce the read/write tolerance and liability of the memory cell but also increase the power consumption of the entire array. In this article, a 3-D circuit HSPICE simulation is used to analyze the impact of the array size and operation voltage on the leakage current in the 3-D VRRAM architecture. The simulation results show that rapidly increasing leakage currents significantly affect the size of 3-D layers. A high read voltage is profitable for enhancing the read margin. However, the leakage current also increases. Alleviating this conflict requires a trade-off when setting the input voltage. A method to improve the array read/write efficiency is proposed by analyzing the influence of the multi-bit operations on the overall leakage current. Finally, this paper explores different methods to reduce the leakage current in the 3-D VRRAM array. The leakage current model proposed in this paper provides an efficient performance prediction solution for the initial design of 3-D VRRAM arrays.

APA, Harvard, Vancouver, ISO, and other styles

43

Li, Guangnian, Qingren Chen, and Hanbin Gu. "Study of Hydrodynamic Interference of Vertical-Axis Tidal Turbine Array." Water 10, no. 9 (September 12, 2018): 1228. http://dx.doi.org/10.3390/w10091228.

Full text

Abstract:

The hydrodynamic interference between tidal turbines must be considered when predicting their overall hydrodynamic performance and optimizing the layout of the turbine array. These factors are of great significance to the development and application of tidal energy. In this paper, the phenomenon of hydrodynamic interference of the tidal turbine array is studied by the hydrodynamic performance forecast program based on an unsteady boundary element model for the vertical-axis turbine array. By changing the relative positions of two turbines in the double turbine array to simulate the arrangement of different turbines, the hydrodynamic interference law between the turbines in the array and the influence of relative positions on the hydrodynamic characteristics in the turbine array are explored. The manner in which the turbines impact each other, the degree of influence, and rules for turbine array arrangement for maximum efficiency of the array will be discussed. The results of this study will provide technical insights to relevant researchers.

APA, Harvard, Vancouver, ISO, and other styles

44

Jiang, Yanyu, Boris Katsnelson, and Oleg A. Godin. "Observations of Noise due to Nonlinear Internal Waves in the ASIAEX Experiment in the South China Sea." Journal of the Acoustical Society of America 152, no. 4 (October 2022): A212. http://dx.doi.org/10.1121/10.0016044.

Full text

Abstract:

Large, transient increases in underwater noise intensity (noise bursts) were repeatedly observed during the ASIAEX experiment on a 48-hydrophone array consisting of vertical and horizontal line arrays. The arrays were located in the South China Sea in the area known for exceptionally strong nonlinear internal waves (NIWs). The ASIAEX experiment was intended to study sound propagation in the presence of NIWs and featured extensive, concurrent acoustic and oceanographic observations. The NIWs propagating past the acoustic array site were characterized using water temperature measurements with a nearby thermistor chain. Remarkable correlation is found between noise intensity increases on the vertical array hydrophones and the NIW presence. Intensity of the noise bursts strongly depends on the hydrophone depth. The low acoustic frequencies below 30–40 Hz are primarily responsible for the noise enhancement during the NIW passage. Analysis of the spectral properties and the depth dependence of the noise intensity suggests the flow noise due to NIW-induced currents as the physical mechanism of the noise bursts in the South China Sea. [Work was supported, part, by ISF award 946/20.]

APA, Harvard, Vancouver, ISO, and other styles

45

Zeng, Chunhong, Wenkui Lin, Tao He, Yukun Zhao, Yuhua Sun, Qi Cui, Xuan Zhang, et al. "Ultraviolet-infrared dual-color photodetector based on vertical GaN nanowire array and graphene." Chinese Optics Letters 18, no. 11 (2020): 112501. http://dx.doi.org/10.3788/col202018.112501.

Full text

APA, Harvard, Vancouver, ISO, and other styles

46

Hoffe, Brian H., Gary F. Margrave, Robert R. Stewart, Darren S. Foltinek, Henry C. Bland, and Peter M. Manning. "Analyzing the effectiveness of receiver arrays for multicomponent seismic exploration." GEOPHYSICS 67, no. 6 (November 2002): 1853–68. http://dx.doi.org/10.1190/1.1527085.

Full text

Abstract:

This paper uses an experimental seismic line recorded with three‐component (3C) receivers to develop a case history demonstrating very little benefit from receiver arrays as compared to point receivers. Two common array designs are tested; they are detrimental to the P‐S wavefield and provide little additional benefit for P‐P data. The seismic data are a 3C 2‐D line recorded at closely spaced (2 m) point receivers over the Blackfoot oil field, Alberta. The 3C receiver arrays are constructed by summing five (one group interval) and ten (two group intervals) point receivers. The shorter array emphasizes signal preservation while the longer array places priority on noise rejection. The effectiveness of the arrays versus the single geophones is compared in both the t−x and f−k domains of common source gathers. The quality of poststack data is also compared by analyzing the f−x spectra for signal bandwidth on both the vertical receiver component (P‐P) and radial receiver component (P‐S) structure stacks produced using these two array design philosophies. The prestack analysis shows that the two arrays effectively suppress coherent noise on both the vertical and radial geophone data and perform reasonably as spatial antialias filters. The poststack analysis reveals that, for both the P‐P and P‐S data, neither of the two arrays significantly improves the quality of the final seismic image over that obtained from point receiver data. For the P‐P data there are subtle differences between the final stacked sections, while for the P‐S data there is a significant deterioration in image quality from the application of the arrays. This P‐S image deterioration is attributed to significant variation of shear‐wave statics across the array. For this specific survey area and acquisition parameters, 3C receiver arrays are unnecessary for P‐P data and are detrimental to P‐S data.

APA, Harvard, Vancouver, ISO, and other styles

47

Saribudak, Mustafa, Dale F. Rucker, and Allan Haas. "Electrical Resistivity Imaging near Abandoned Steel Oil Wells: Five Case Studies, USA." Journal of Environmental and Engineering Geophysics 25, no. 4 (December 2020): 545–56. http://dx.doi.org/10.32389/jeeg20-048.

Full text

Abstract:

Abandoned wells may act as conduits for the contamination of groundwater by oil field brines and other pollutants. The steel casings of abandoned wells eventually develop leaks, which if not properly plugged, can allow pollutants to reach freshwater aquifers that supply drinking water. Resistivity surveys were conducted in the vicinity of five abandoned oil wells in order to characterize the near-surface geology and to determine the effects of the steel casings and potential leakage. The arrays consisted of dipole-dipole (DD) and inverse Schlumberger (SLB) arrays. The effects from steel cased wells can manifest as low resistivity anomalies in the vicinity of the casings, depending on proximity of the line to the well, well location along the line, and the specific array used. These features appear as vertical, circular, elliptical, and bell-like anomalies. However, in some instances with the SLB array, the data appear not to be affected by the presence of steel casings. This observation is significant because resistivity surveys utilizing the SLB array can provide reliable information on near-surface geology next to abandoned wells, and horizontal and vertical extension of brine impacted areas due to leaking abandoned oil wells. The DD array, on the other hand, is better at locating potentially hidden abandoned wells but interpreting subsurface structure or contamination with the array is more difficult.

APA, Harvard, Vancouver, ISO, and other styles

48

Szalai, Sándor, László Szarka, Erno˝ Prácser, Frank Bosch, Imre Müller, and Pascal Turberg. "Geoelectric mapping of near‐surface karstic fractures by using null arrays." GEOPHYSICS 67, no. 6 (November 2002): 1769–78. http://dx.doi.org/10.1190/1.1527077.

Full text

Abstract:

The term “null array” is introduced for those electrode configurations where the measured potential difference is zero above a homogeneous half‐space when using a measuring dipole M0N0. Different types of null arrays (three‐electrode, Schlumberger, and dipole axial/equatorial null arrays) and their corresponding traditional arrays are studied. It was shown in a field study carried out in a karstified limestone area covered by thin sediments that it is possible to obtain geologically meaningful results with null‐array techniques. The main features of the null‐array data are as follows. (1) Null‐array data appear to be more spatially variable than the classical data. The spatial variability provides information about the presence of karstic fractures in the subsurface; (2) The null‐array anomalies caused by nearly vertical karstic fractures in the limestone basement do not decay with depth as quickly as the classical array anomalies. (3) The strike direction of the fractures is much less ambiguous than that found by using classical arrays. Nevertheless, the depth variation of the basement is more reliably observed in geoelectric anomalies obtained using traditional arrays. Therefore a joint use of classical arrays and their corresponding null methods is recommended, because the combined methods provide more information about the subsurface structure.

APA, Harvard, Vancouver, ISO, and other styles

49

Karagiozis, A., G. D. Raithby, and K. G. T. Hollands. "Natural Convection Heat Transfer From Arrays of Isothermal Triangular Fins in Air." Journal of Heat Transfer 116, no. 1 (February 1, 1994): 105–11. http://dx.doi.org/10.1115/1.2910842.

Full text

Abstract:

Measurements of the heat transfer to air by natural convection from arrays of isothermal triangular fins on a vertical base plate are reported for several array geometries, for a large range of Rayleigh number, and for two orientations (vertical fins and horizontal fins). The data are believed to be the first available for this important geometry. A single equation is provided that correlates the measured Nusselt numbers for the vertical orientation with an rms error of 4.8 percent. The horizontal fin orientation was shown to have inferior heat transfer performance.

APA, Harvard, Vancouver, ISO, and other styles

50

Chang, Chia-Jui, Lih-Ren Chen, Kuo-Bin Hong, Wei-Chih Weng, Bing-Hong Chuang, Hao-Chung Kuo, and Tien-Chang Lu. "A Simple Method to Build High Power PCSEL Array with Isolation Pattern Design." Crystals 12, no. 10 (October 10, 2022): 1432. http://dx.doi.org/10.3390/cryst12101432.

Full text

Abstract:

Photonic crystal surface-emitting lasers (PCSELs) hold promising properties of both edge emitting lasers (EELs) and vertical-cavity surface-emitting lasers (VCSELs). They possess high output power while radiating light vertically, being thought of as the next generation laser source. One of the main advantages of PCSELs is their scalability of size and power, which makes them applicable to high power applications or long-distance detection. However, due to problems such as current injection and mode competition, there are limits on their dimensions. To further increase the power, the capability of two-dimensional array integration paves the way. In this work, we demonstrate a new method to fabricate PCSEL arrays by defining an isolation pattern. We also investigate the influence of aperture size and array arrangement on lasing performance.

APA, Harvard, Vancouver, ISO, and other styles

Journal articles on the topic 'Vertical array'

Create a spot-on reference in APA, MLA, Chicago, Harvard, and other styles