Статті в журналах: "Correlated interferometry"

1

Yurke, B. "Interferometry with correlated fermions." Physica B+C 151, no. 1-2 (July 1988): 286–90. http://dx.doi.org/10.1016/0378-4363(88)90179-9.

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2

Ayala-Garcia, Daniella, Andrew Curtis, and Michal Branicki. "Seismic Interferometry from Correlated Noise Sources." Remote Sensing 13, no. 14 (July 9, 2021): 2703. http://dx.doi.org/10.3390/rs13142703.

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It is a well-established principle that cross-correlating seismic observations at different receiver locations can yield estimates of band-limited inter-receiver Green’s functions. This principle, known as Green’s function retrieval or seismic interferometry, is a powerful technique that can transform noise into signals which enable remote interrogation and imaging of the Earth’s subsurface. In practice it is often necessary and even desirable to rely on noise already present in the environment. Theory that underpins many applications of ambient noise interferometry assumes that the sources of noise are uncorrelated in time. However, many real-world noise sources such as trains, highway traffic and ocean waves are inherently correlated in space and time, in direct contradiction to the these theoretical foundations. Applying standard interferometric techniques to recordings from correlated energy sources makes the Green’s function liable to estimation errors that so far have not been fully accounted for theoretically nor in practice. We show that these errors are significant for common noise sources, always perturbing or entirely obscuring the phase one wishes to retrieve. Our analysis explains why stacking may reduce the phase errors, but also shows that in commonly encountered circumstances stacking will not remediate the problem. This analytical insight allowed us to develop a novel workflow that significantly mitigates effects arising from the use of correlated noise sources. Our methodology can be used in conjunction with already existing approaches, and improves results from both correlated and uncorrelated ambient noise. Hence, we expect it to be widely applicable in ambient noise studies.

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3

Pavičić, Mladen. "Spin-correlated interferometry with beam splitters: preselection of spin-correlated photons." Journal of the Optical Society of America B 12, no. 5 (May 1, 1995): 821. http://dx.doi.org/10.1364/josab.12.000821.

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4

Paterova, Anna V., Dmitry A. Kalashnikov, Egor Khaidarov, Hongzhi Yang, Tobias W. W. Mass, Ramón Paniagua-Domínguez, Arseniy I. Kuznetsov, and Leonid A. Krivitsky. "Non-linear interferometry with infrared metasurfaces." Nanophotonics 10, no. 6 (March 22, 2021): 1775–84. http://dx.doi.org/10.1515/nanoph-2021-0011.

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Abstract The optical elements comprised of sub-diffractive light scatterers, or metasurfaces, hold a promise to reduce the footprint and unfold new functionalities of optical devices. A particular interest is focused on metasurfaces for manipulation of phase and amplitude of light beams. Characterisation of metasurfaces can be performed using interferometry, which, however, may be cumbersome, specifically in the infrared (IR) range. Here, we realise a new method for characterising metasurfaces operating in the telecom IR range using accessible components for visible light. Correlated IR and visible photons are launched into a non-linear interferometer so that the phase profile, imposed by the metasurface on the IR photons, modifies the interference at the visible photon wavelength. Furthermore, we show that this concept can be used for broadband manipulation of the intensity profile of a visible beam using a single IR metasurface. Our method unfolds the potential of quantum interferometry for the characterization of advanced optical elements.

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5

Zhang, Shane, Lili Feng, and Michael H. Ritzwoller. "Three-station interferometry and tomography: coda versus direct waves." Geophysical Journal International 221, no. 1 (January 28, 2020): 521–41. http://dx.doi.org/10.1093/gji/ggaa046.

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SUMMARY Traditional two-station ambient noise interferometry estimates the Green’s function between a pair of synchronously deployed seismic stations. Three-station interferometry considers records observed three stations at a time, where two of the stations are considered receiver–stations and the third is a source–station. Cross-correlations between records at the source–station with each of the receiver–stations are correlated or convolved again to estimate the Green’s function between the receiver–stations, which may be deployed asynchronously. We use data from the EarthScope USArray in the western United States to compare Rayleigh wave dispersion obtained from two-station and three-station interferometry. Three three-station interferometric methods are distinguished by the data segment utilized (coda-wave or direct-wave) and whether the source–stations are constrained to lie in stationary phase zones approximately inline with the receiver–stations. The primary finding is that the three-station direct wave methods perform considerably better than the three-station coda-wave method and two-station ambient noise interferometry for obtaining surface wave dispersion measurements in terms of signal-to-noise ratio, bandwidth, and the number of measurements obtained, but possess small biases relative to two-station interferometry. We present a ray-theoretic correction method that largely removes the bias below 40 s period and reduces it at longer periods. Three-station direct-wave interferometry provides substantial value for imaging the crust and uppermost mantle, and its ability to bridge asynchronously deployed stations may impact the design of seismic networks in the future.

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6

Pavičić, Mladen, and Johann Summhammer. "Interferometry with Two Pairs of Spin Correlated Photons." Physical Review Letters 73, no. 24 (December 12, 1994): 3191–94. http://dx.doi.org/10.1103/physrevlett.73.3191.

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7

de Groot, Peter J. "Correlated errors in phase-shifting laser Fizeau interferometry." Applied Optics 53, no. 19 (June 30, 2014): 4334. http://dx.doi.org/10.1364/ao.53.004334.

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8

Lam, M. M., and C. Dewdney. "Locality and nonlocality in correlated two-particle interferometry." Physics Letters A 150, no. 3-4 (November 1990): 127–35. http://dx.doi.org/10.1016/0375-9601(90)90107-y.

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9

Su, Hang, Ruifang Ye, Fang Cheng, Changcai Cui, and Qing Yu. "A Straightness Error Compensation System for Topography Measurement Based on Thin Film Interferometry." Photonics 8, no. 5 (April 30, 2021): 149. http://dx.doi.org/10.3390/photonics8050149.

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Straightness error compensation is a critical process for high-accuracy topography measurement. In this paper, a straightness measurement system was presented based on the principle of fringe interferometry. This system consisted of a moving optical flat and a stationary prism placed close to each other. With a properly aligned incident light beam, the air wedge between the optical flat and the prism would generate the interferogram, which was captured by a digital camera. When the optical flat was moving with the motion stage, the variation in air wedge thickness due to the imperfect straightness of the guideway would lead to a phase shift of the interferogram. The phase shift could be calculated, and the air wedge thickness could be measured accordingly using the image processing algorithm developed in-house. This air wedge thickness was directly correlated with the straightness of the motion stage. A commercial confocal sensor was employed as the reference system. Experimental results showed that the repeatability of the proposed film interferometer represented by σ was within 25 nm. The measurement deviation between the film interferometer and the reference confocal sensor was within ±0.1 µm. Compared with other interferometric straightness measurement technologies, the presented methodology was featured by a simplified design and good environment robustness. The presented system could potentially be able to measure straightness in both linear and angular values, and the main focus was to analyze its linear value measurement capability.

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10

Csörgo, T. "Pion interferometry for strongly correlated spacetime and momentum space." Nuclear Physics A 517, no. 3-4 (October 29, 1990): 588–98. http://dx.doi.org/10.1016/0375-9474(90)90220-g.

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11

Kammerer, J., A. Mérand, M. J. Ireland, and S. Lacour. "Increasing the achievable contrast of infrared interferometry with an error correlation model." Astronomy & Astrophysics 644 (December 2020): A110. http://dx.doi.org/10.1051/0004-6361/202038563.

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Context. Interferometric observables are strongly correlated, yet it is common practice to ignore these correlations in the data analysis process. Aims. We develop an empirical model for the correlations present in Very Large Telescope Interferometer GRAVITY data and show that properly accounting for them yields fainter detection limits and increases the reliability of potential detections. Methods. We extracted the correlations of the (squared) visibility amplitudes and the closure phases directly from intermediate products of the GRAVITY data reduction pipeline and fitted our empirical models to them. Then, we performed model fitting and companion injection and recovery tests with both simulated and real GRAVITY data, which are affected by correlated noise, and compared the results when ignoring the correlations and when properly accounting for them with our empirical models. Results. When accounting for the correlations, the faint source detection limits improve by a factor of up to ∼2 at angular separations > 20 mas. For commonly used detection criteria based on χ2 statistics, this mostly results in claimed detections being more reliable. Conclusions. Ignoring the correlations present in interferometric data is a dangerous assumption which might lead to a large number of false detections. The commonly used detection criteria (e.g. in the model fitting pipeline CANDID) are only reliable when properly accounting for the correlations; furthermore, instrument teams should work on providing full covariance matrices instead of statistically independent error bars as part of the official data reduction pipelines.

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12

Kim, Taesoo, Olivier Pfister, Murray J. Holland, Jaewoo Noh, and John L. Hall. "Influence of decorrelation on Heisenberg-limited interferometry with quantum correlated photons." Physical Review A 57, no. 5 (May 1, 1998): 4004–13. http://dx.doi.org/10.1103/physreva.57.4004.

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13

Shirzaei, M., and R. Bürgmann. "Topography correlated atmospheric delay correction in radar interferometry using wavelet transforms." Geophysical Research Letters 39, no. 1 (January 2012): n/a. http://dx.doi.org/10.1029/2011gl049971.

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14

Lu, Kai, Zhaolun Liu, Sherif Hanafy, and Gerard Schuster. "Noise reduction with reflection supervirtual interferometry." GEOPHYSICS 85, no. 3 (May 1, 2020): V249—V256. http://dx.doi.org/10.1190/geo2019-0571.1.

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To image deeper portions of the earth, geophysicists must record reflection data with much greater source-receiver offsets. The problem with these data is that the signal-to-noise ratio (S/N) significantly diminishes with greater offset. In many cases, the poor S/N makes the far-offset reflections imperceptible on the shot records. To mitigate this problem, we have developed supervirtual reflection interferometry (SVI), which can be applied to far-offset reflections to significantly increase their S/N. The key idea is to select the common pair gathers where the phases of the correlated reflection arrivals differ from one another by no more than a quarter of a period so that the traces can be coherently stacked. The traces are correlated and summed together to create traces with virtual reflections, which in turn are convolved with one another and stacked to give the reflection traces with much stronger S/Ns. This is similar to refraction SVI except far-offset reflections are used instead of refractions. The theory is validated with synthetic tests where SVI is applied to far-offset reflection arrivals to significantly improve their S/N. Reflection SVI is also applied to a field data set where the reflections are too noisy to be clearly visible in the traces. After the implementation of reflection SVI, the normal moveout velocity can be accurately picked from the SVI-improved data, leading to a successful poststack migration for this data set.

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15

Hering, Marco, Klaus Körner, and Bernd Jähne. "Correlated speckle noise in white-light interferometry: theoretical analysis of measurement uncertainty." Applied Optics 48, no. 3 (January 14, 2009): 525. http://dx.doi.org/10.1364/ao.48.000525.

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16

Pavičić, Mladen. "Spin-correlated interferometry for polarized and unpolarized photons on a beam splitter." Physical Review A 50, no. 4 (October 1, 1994): 3486–91. http://dx.doi.org/10.1103/physreva.50.3486.

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17

Varga, J., P. Ábrahám, L. Chen, Th Ratzka, K. É. Gabányi, Á. Kóspál, A. Matter, et al. "VLTI/MIDI atlas of disks around low- and intermediate-mass young stellar objects." Astronomy & Astrophysics 617 (September 2018): A83. http://dx.doi.org/10.1051/0004-6361/201832599.

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Context. Protoplanetary disks show large diversity regarding their morphology and dust composition. With mid-infrared interferometry the thermal emission of disks can be spatially resolved, and the distribution and properties of the dust within can be studied. Aims. Our aim is to perform a statistical analysis on a large sample of 82 disks around low- and intermediate-mass young stars, based on mid-infrared interferometric observations. We intend to study the distribution of disk sizes, variability, and the silicate dust mineralogy. Methods. Archival mid-infrared interferometric data from the MIDI instrument on the Very Large Telescope Interferometer are homogeneously reduced and calibrated. Geometric disk models are used to fit the observations to get spatial information about the disks. An automatic spectral decomposition pipeline is applied to analyze the shape of the silicate feature. Results. We present the resulting data products in the form of an atlas, containing N band correlated and total spectra, visibilities, and differential phases. The majority of our data can be well fitted with a continuous disk model, except for a few objects, where a gapped model gives a better match. From the mid-infrared size–luminosity relation we find that disks around T Tauri stars are generally colder and more extended with respect to the stellar luminosity than disks around Herbig Ae stars. We find that in the innermost part of the disks (r ≲ 1 au) the silicate feature is generally weaker than in the outer parts, suggesting that in the inner parts the dust is substantially more processed. We analyze stellar multiplicity and find that in two systems (AB Aur and HD 72106) data suggest a new companion or asymmetric inner disk structure. We make predictions for the observability of our objects with the upcoming Multi-AperTure mid-Infrared SpectroScopic Experiment (MATISSE) instrument, supporting the practical preparations of future MATISSE observations of T Tauri stars.

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18

Giulietti, A., M. Galimberti, A. Gamucci, D. Giulietti, L. A. Gizzi, P. Koester, L. Labate, et al. "Search for stable propagation of intense femtosecond laser pulses in gas." Laser and Particle Beams 25, no. 4 (December 2007): 513–21. http://dx.doi.org/10.1017/s0263034607000079.

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AbstractWe report and discuss experimental results on the propagation of CPA pulses of moderately relativistic intensity in gas: they evidence the effects of the precursor pedestals of the main pulse. Details of great interest were observed for the first time with high quality femtosecond 90-degree interferometry. The interferometric data are also correlated with imaging and spectroscopy data of laser pulse transmitted through the gas. The most relevant physical features are confirmed by a numerical code which simulates the laser pulse propagation self-consistently with the ionization of the gas. We found that in this regime, the propagation of the intense femtosecond pulse is basically stable apart from very weak refractive effects. In order to allow propagation at fixed intensity along an optical path larger than the Rayleigh range, we performed a first successful attempt at producing hollow plasma channels able to guide the pulse.

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19

Wei Zhen, 韦震, 陆荣华 Lu Ronghua, 喻虹 Yu Hong, 谈志杰 Tan Zhijie, 朱瑞国 Zhu Ruiguo, and 韩申生 Han Shensheng. "Research on Intensity-Correlated Interferometry with Ultra-Weak Light Based on Coincidence Counting." Acta Optica Sinica 40, no. 1 (2020): 0111013. http://dx.doi.org/10.3788/aos202040.0111013.

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20

Cramer, John G., Daniel Ferenc, and Marek Gaździcki. "Using Maximum Likelihood analysis in HBT interferometry: bin-free treatment of correlated errors." Nuclear Instruments and Methods in Physics Research Section A: Accelerators, Spectrometers, Detectors and Associated Equipment 351, no. 2-3 (December 1994): 489–92. http://dx.doi.org/10.1016/0168-9002(94)91379-x.

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21

Lachaume, Régis, Markus Rabus, Andrés Jordán, Rafael Brahm, Tabetha Boyajian, Kaspar von Braun, and Jean-Philippe Berger. "Towards reliable uncertainties in IR interferometry: the bootstrap for correlated statistical and systematic errors." Monthly Notices of the Royal Astronomical Society 484, no. 2 (January 16, 2019): 2656–73. http://dx.doi.org/10.1093/mnras/stz114.

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22

Thapa, S., R. S. Chatterjee, K. B. Singh, and D. Kumar. "LAND SUBSIDENCE MONITORING USING PS-InSAR TECHNIQUE FOR L-BAND SAR DATA." ISPRS - International Archives of the Photogrammetry, Remote Sensing and Spatial Information Sciences XLI-B7 (October 14, 2016): 995–97. http://dx.doi.org/10.5194/isprs-archives-xli-b7-995-2016.

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Differential SAR-Interferometry (D-InSAR) is one of the potential source to measure land surface motion induced due to underground coal mining. However, this technique has many limitation such as atmospheric in homogeneities, spatial de-correlation, and temporal decorrelation. Persistent Scatterer Interferometry synthetic aperture radar (PS-InSAR) belongs to a family of time series InSAR technique, which utilizes the properties of some of the stable natural and anthropogenic targets which remain coherent over long time period. In this study PS-InSAR technique has been used to monitor land subsidence over selected location of Jharia Coal field which has been correlated with the ground levelling measurement. This time series deformation observed using PS InSAR helped us to understand the nature of the ground surface deformation due to underground mining activity.

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23

Hu, Huiqin, Xinyi Ren, Zhaoyang Wen, Xingtong Li, Yan Liang, Ming Yan, and E. Wu. "Single-Pixel Photon-Counting Imaging Based on Dual-Comb Interferometry." Nanomaterials 11, no. 6 (May 24, 2021): 1379. http://dx.doi.org/10.3390/nano11061379.

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We propose and experimentally demonstrate single-pixel photon counting imaging based on dual-comb interferometry at 1550 nm. Different from traditional dual-comb imaging, this approach enables imaging at the photon-counting regime by using single-photon detectors combined with a time-correlated single-photon counter to record the returning photons. The illumination power is as low as 14 pW, corresponding to 2.2 × 10−3 photons/pulse. The lateral resolution is about 50 μm. This technique paves the way for applying dual-comb in remote sensing and imaging.

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24

Sarvandani, Mohamadhasan Mohamadian, Emanuel Kästle, Lapo Boschi, Sylvie Leroy, and Mathilde Cannat. "Seismic Ambient Noise Imaging of a Quasi-Amagmatic Ultra-Slow Spreading Ridge." Remote Sensing 13, no. 14 (July 17, 2021): 2811. http://dx.doi.org/10.3390/rs13142811.

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Passive seismic interferometry has become very popular in recent years in exploration geophysics. However, it has not been widely applied in marine exploration. The purpose of this study is to investigate the internal structure of a quasi-amagmatic portion of the Southwest Indian Ridge by interferometry and to examine the performance and reliability of interferometry in marine explorations. To reach this goal, continuous vertical component recordings from 43 ocean bottom seismometers were analyzed. The recorded signals from 200 station pairs were cross-correlated in the frequency domain. The Bessel function method was applied to extract phase–velocity dispersion curves from the zero crossings of the cross-correlations. An average of all the dispersion curves was estimated in a period band 1–10 s and inverted through a conditional neighborhood algorithm which led to the final 1D S-wave velocity model of the crust and upper mantle. The obtained S-wave velocity model is in good agreement with previous geological and geophysical studies in the region and also in similar areas. We find an average crustal thickness of 7 km with a shallow layer of low shear velocities and high Vp/Vs ratio. We infer that the uppermost 2 km are highly porous and may be strongly serpentinized.

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25

Arbogast, Jannik, Rolf Schaller, Magnus Rohde, and Hans Jürgen Seifert. "Thermal wave interferometry measurements correlated to microstructural properties and bonding behavior of thermally sprayed coatings." Surface and Coatings Technology 402 (November 2020): 126298. http://dx.doi.org/10.1016/j.surfcoat.2020.126298.

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26

Tovmassian, Gaghik H., Jochen Greiner, Stefanie Komossa, Margarita Rosado, and Anabel Arrieta. "The M31-WC6 star MLA 1159 and its ionized nebula BA1-642." Symposium - International Astronomical Union 193 (1999): 501–2. http://dx.doi.org/10.1017/s0074180900206189.

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Aimed at identifying supersoft X-ray sources in ionization nebulae, we have searched for extended optical emission within the X-ray error boxes of the 15 supersoft sources in M31 (Greiner et al. 1996). One optical nebula was found, of which we obtained spectroscopy, narrow-band imaging and FP-interferometry, to determine its relation to the positionally correlated supersoft X-ray source RX J0045.5+4206. M31 has been surveyed several times with different goals. Baade & Arp (1964) compiled a list of 688 emission nebula in M 31. One of these nebulae, BA1-642 (PAV 78915 in the catalog of Pellet et al. 1978), was found by cross-correlation with supersoft X-ray sources. The central object MLA 1159 of this nebula has been classified WR (Meyssonier et al. 1993). Here we confirm this new WR star and discuss the star as well the ring-like nebula around it. We did direct imaging of RX J0045.4+4206 with narrow-band nebular filters, spectroscopy of the central star and surrounding nebulae, and we observed the nebula with the FP-interferometer PUMA. All observations were carried out at OAN SPM, México.

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27

Pradyumna, S. T., E. Losero, P. Traina, I. Ruo-Berrchera, I. Degiovanni, M. Zucco, and M. Genovese. "Quantum enhanced correlated interferometry for quantum gravity tests: the experimental set-up and the locking scheme." Journal of Physics: Conference Series 1275 (September 2019): 012020. http://dx.doi.org/10.1088/1742-6596/1275/1/012020.

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28

Molimard, J., R. Cordero, and A. Vautrin. "A Signal to Noise Optimization Algorithm for Speckle Interferometry Applications." Applied Mechanics and Materials 13-14 (July 2008): 29–38. http://dx.doi.org/10.4028/www.scientific.net/amm.13-14.29.

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Optical Full Field Techniques (OFFT) are more and more utilized by mechanical laboratories. Among these methods, interferometry techniques (mainly composed of Speckle/Grating Interferometry or Speckle/Grating Shearography) are more difficult to use in a mechanical lab context, because of their sensitivity to external vibrations (except shearography), and because of the global lack of optical culture of mechanical engineers. Speckle-based methods are of great practical interest for the users, but their signal to noise ratio (SNR) is affected by the rigid body motion of the specimen. Here, the speckle decorrelation is minimized at local scale directly using the SNR. First, a shearography experiment is modeled to characterize the recorrelation procedure for a rigid body motion, a constant strain map and finally a high degree of localization. The mean noise level is found to be 6 times higher than a fully-correlated phase map for a 1 pixel speckle size. Last, a first application to a single-ply fabric composite lamina is shown. Resulting strain maps are of high quality with a very low spatial resolution (4 pixels). The local bending / global tension coupling effect is clearly put in evidence.

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29

Gipple, K. L., and D. Hoyns. "Measurement of the Out-of-Plane Shear Response of Thick Section Composite Materials Using the V-Notched Beam Specimen." Journal of Composite Materials 28, no. 6 (April 1994): 543–72. http://dx.doi.org/10.1177/002199839402800604.

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The out-of-plane shear response of thick, unidirectional and crossply, AS4/3501-6 and S2 glass/3501-6 laminates was investigated theoretically and experimentally using V-notched beam (Iosipescu) specimens. Strains were monitored in the specimen test sections using conventional strain gages, moiré interferometry and full section strain gages. Crossply laminates exhibited a fairly uniform strain distribution away from the notches, while the unidirectional specimens were characterized by a nonuniform distribution. Measured strains correlated very well with predicted strains from specimen finite element analyses using nonlinear elastic material properties.

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30

Kim, Taesoo, Olivier Pfister, Murray J. Holland, Jaewoo Noh, and John L. Hall. "Erratum: Influence of decorrelation on Heisenberg-limited interferometry with quantum correlated photons [Phys. Rev. A57, 4004 (1998)]." Physical Review A 58, no. 3 (September 1, 1998): 2617. http://dx.doi.org/10.1103/physreva.58.2617.2.

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31

Wittkowski, M., G. Rau, A. Chiavassa, S. Höfner, M. Scholz, P. R. Wood, W. J. de Wit, F. Eisenhauer, X. Haubois, and T. Paumard. "VLTI-GRAVITY measurements of cool evolved stars." Astronomy & Astrophysics 613 (May 2018): L7. http://dx.doi.org/10.1051/0004-6361/201833029.

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Context. Dynamic model atmospheres of Mira stars predict variabilities in the photospheric radius and in atmospheric molecular layers which are not yet strongly constrained by observations. Aims. Here we measure the variability of the oxygen-rich Mira star R Peg in near-continuum and molecular bands. Methods. We used near-infrared K-band spectro-interferometry with a spectral resolution of about 4000 obtained at four epochs between post-maximum and minimum visual phases employing the newly available GRAVITY beam combiner at the Very Large Telescope Interferometer (VLTI). Results. Our observations show a continuum radius that is anti-correlated with the visual lightcurve. Uniform disc (UD) angular diameters at a near-continuum wavelength of 2.25 μm are steadily increasing with values of 8.7 ± 0.1 mas, 9.4 ± 0.1 mas, 9.8 ± 0.1 mas, and 9.9 ± 0.1 mas at visual phases of 0.15, 0.36, 0,45, 0.53, respectively. UD diameters at a bandpass around 2.05 μm, dominated by water vapour, follow the near-continuum variability at larger UD diameters between 10.7 mas and 11.7 mas. UD diameters at the CO 2–0 bandhead, instead, are correlated with the visual lightcurve and anti-correlated with the near-continuum UD diameters, with values between 12.3 mas and 11.7 mas. Conclusions. The observed anti-correlation between continuum radius and visual lightcurve is consistent with an earlier study of the oxygen-rich Mira S Lac, and with recent 1D CODEX dynamic model atmosphere predictions. The amplitude of the variation is comparable to the earlier observations of S Lac, and smaller than predicted by CODEX models. The wavelength-dependent visibility variations at our epochs can be reproduced by a set of CODEX models at model phases between 0.3 and 0.6. The anti-correlation of water vapour and CO contributions at our epochs suggests that these molecules undergo different processes in the extended atmosphere along the stellar cycle. The newly available GRAVITY instrument is suited to conducting longer time series observations, which are needed to provide strong constraints on the model-predicted intra- and inter-cycle variability.

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32

Morris, Kim, Shusun Li, and Martin Jeffries. "Meso- and microscale sea-ice motion in the East Siberian Sea as determined from ERS-1 SAR Data." Journal of Glaciology 45, no. 150 (1999): 370–83. http://dx.doi.org/10.3189/s0022143000001878.

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AbstractSynthetic aperture radar- (SAR-)derived ice-motion vectors and SAR interferometry were used to study the sea-ice conditions in the region between the coast and 75° N (~ 560 km) in the East Siberian Sea in the vicinity of the Kolyma River. ERS-1 SAR data were acquired between 24 December 1993 and 30 March 1994 during the 3 day repeat Ice Phase of the satellite. The time series of the ice-motion vector fields revealed rapid (3 day) changes in the direction and displacement of the pack ice. Longer-term (≥ 1 month) trends also emerged which were related to changes in large-scale atmospheric circulation. On the basis of this time series, three sea-ice zones were identified: the near-shore, stationary-ice zone; a transitional-ice zone;and the pack-ice zone. Three 3 day interval and one 9 day interval interferometric sets (amplitude, correlation and phase diagrams) were generated for the end of December, the begining of February and mid-March. They revealed that the stationary-ice zone adjacent to the coast is in constant motion, primarily by lateral displacement, bending, tilting and rotation induced by atmospheric/oceanic forcing. The interferogram patterns change through time as the sea ice becomes thicker and a network of cracks becomes established in the ice cover. It was found that the major features in the interferograms were spatially correlated with sea-ice deformation features (cracks and ridges) and major discontinuities in ice thickness.

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33

Morris, Kim, Shusun Li, and Martin Jeffries. "Meso- and microscale sea-ice motion in the East Siberian Sea as determined from ERS-1 SAR Data." Journal of Glaciology 45, no. 150 (1999): 370–83. http://dx.doi.org/10.1017/s0022143000001878.

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Анотація:

Abstract Synthetic aperture radar- (SAR-)derived ice-motion vectors and SAR interferometry were used to study the sea-ice conditions in the region between the coast and 75° N (~ 560 km) in the East Siberian Sea in the vicinity of the Kolyma River. ERS-1 SAR data were acquired between 24 December 1993 and 30 March 1994 during the 3 day repeat Ice Phase of the satellite. The time series of the ice-motion vector fields revealed rapid (3 day) changes in the direction and displacement of the pack ice. Longer-term (≥ 1 month) trends also emerged which were related to changes in large-scale atmospheric circulation. On the basis of this time series, three sea-ice zones were identified: the near-shore, stationary-ice zone; a transitional-ice zone;and the pack-ice zone. Three 3 day interval and one 9 day interval interferometric sets (amplitude, correlation and phase diagrams) were generated for the end of December, the begining of February and mid-March. They revealed that the stationary-ice zone adjacent to the coast is in constant motion, primarily by lateral displacement, bending, tilting and rotation induced by atmospheric/oceanic forcing. The interferogram patterns change through time as the sea ice becomes thicker and a network of cracks becomes established in the ice cover. It was found that the major features in the interferograms were spatially correlated with sea-ice deformation features (cracks and ridges) and major discontinuities in ice thickness.

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34

Tapete, Deodato, and Francesca Cigna. "Site-Specific Analysis of Deformation Patterns on Archaeological Heritage by Satellite Radar Interferometry." MRS Proceedings 1374 (2012): 283–95. http://dx.doi.org/10.1557/opl.2012.1397.

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ABSTRACTExploitation of satellite radar interferometry on huge cultural heritage sites can facilitate the recognition of spatially distributed deformation patterns, whose morphology, jointly with the analysis of displacement time series, could clarify the nature of ongoing deterioration phenomena threatening the conservation of exposed archaeological heritage. Radar-interpretation is used on selected case studies located in Southern Italy to demonstrate the feasibility of Persistent Scatterers (PS) analyses for site-specific detection of superficial deformation, correlated to natural and/or human-induced instability processes. Evidence of subsidence for the radar targets identified within the archaeological area of Capo Colonna, Central Calabria, confirms the susceptibility of the entire promontory to ground instability, with potential effects on the ruins. Similarly, the uplift/subsidence patterns on the monumental area of Pozzuoli, W of Naples, testify the exposure of the geologic substratum underneath the archaeological structures to the active dynamics of the Campi Flegrei volcanic complex. Finally, the satellite analysis on the Valley of the Temples in Agrigento, Sicily, exemplifies the capability to distinguish differential displacement trends and seasonal variations within single PS time series.

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Shi, Xuguo, Shaocheng Zhang, Mi Jiang, Yuanyuan Pei, Tengteng Qu, Jinhu Xu, and Chen Yang. "Spatial and temporal subsidence characteristics in Wuhan (China), during 2015–2019, inferred from Sentinel-1 synthetic aperture radar (SAR) interferometry." Natural Hazards and Earth System Sciences 21, no. 8 (August 3, 2021): 2285–97. http://dx.doi.org/10.5194/nhess-21-2285-2021.

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Abstract. Ground subsidence is regarded as one of the most common geohazards, accompanied with the rapid urban expansion in recent years. In the last 2 decades, Wuhan, located in the alluvial Jianghan Plain, has experienced great urban expansion with increased subsidence issues, i.e., soft foundation subsidence and karst collapse. Here we investigated subsidence rates in Wuhan with 2015–2019 Sentinel-1 synthetic aperture radar (SAR) images. We found that the overall subsidence over the Wuhan region is significantly correlated with the distribution of engineering geological subregions (EGSs). We further validated the interferometric SAR (InSAR) measurements with better than 5 mm accuracy by comparing with leveling measurements. Subsidence centers in Qingling–Jiangdi, Houhu, Qingshan, and Dongxihu were identified with displacement rates of approximately 30 mm/yr. Our results demonstrated that the dominant driving factor is ongoing construction, and the fact that the subsidence centers shifted with construction intensities. The Qingling–Jiangdi area in our study is a well-known site of karst collapse. We find that the nonlinear subsidence of this area is correlated with the seasonal rainfall.

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Qu, T., Z. Su, H. Yang, X. Shi, and W. Shao. "LARGE-SCALE SUBSIDENCE GEOHAZARD MONITORING WITH SENTINEL-1 SAR INTERFEROMETRY IN CENTRAL LISHUI (CHINA)." International Archives of the Photogrammetry, Remote Sensing and Spatial Information Sciences XLIII-B3-2021 (June 29, 2021): 873–78. http://dx.doi.org/10.5194/isprs-archives-xliii-b3-2021-873-2021.

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Abstract. Ground subsidence has become a serious problem along with the rapid urban expansions. Compared with traditional point-based ground survey techniques (GPS, levelling measurement and in-situ sensors), SAR Interferometry are quite appreciated for large-scale subsidence monitoring with long term and high accuracy. In this study, we focused on large-scale subsidence geohazard monitoring of central Lishui (China) and extracted subsidence velocity map of Liandu District. 57 Sentinle-1 SAR images from April 2019 to September 2020 are analysed with SBAS-InSAR technique. The overall subsidence of Liandu is significantly correlated with the distributions of construction engineering sites with displacement velocity of approximately 30–60 mm/yr. Various types of urban ground subsidence could be identified, including the overall settlement of large construction site, the slope deformation of construction excavation, significant settlement of refuse landfill and mountain crossing tunnel, and small deformation of highvoltage towers in mountainous areas. Our results indicated that the rapid urban developments are the dominant impact factors of subsidence in Lishui, China.

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Li, Shenglin, Pingsong Zhang, and Chaoqiang Xi. "Impulse Processing Algorithm for Random Source Signals of Roadheaders That Is Based on Compound Interferometry." Journal of Environmental and Engineering Geophysics 26, no. 1 (March 2021): 13–24. http://dx.doi.org/10.32389/jeeg20-026.

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The boom-type roadheader is the main equipment for realizing the mechanization of coal drifting in coal mines, and it is an indispensable production equipment in major coal-producing countries. Substantial vibrations are generated during the operation of a roadheader; these vibrations carry substantial energy and, thus, can be regarded as a potential source and used for seismic advance detection purposes in mine drifts. Compared with a conventional exploration source, a roadheader source produces a complex continuous random signal. The shape of a seismic wavelet is uncertain and its duration is relatively long; thus, it must be processed into a conventional pulse signal before it can be used for subsequent processing and analysis. Therefore, based on the advantages of seismic interferometry in random signal processing, two seismic interference techniques, namely, deconvolution and cross-correlation, are introduced for constructing a compound interference algorithm. On the basis of a theoretically derived formula, a random signal impulse processing experiment is conducted using field-acquired source signals from a roadheader; this approach resolves the problem that cross-correlation alone cannot yield ideal results. Hence, a feasible algorithm for the impulse processing of a random signal, namely, the compound interference algorithm, is proposed. The algorithm deconvolves each seismic trace to obtain the reference trace and other receiver traces after compressing the wavelet. Then, the reference trace and each receiver trace are cross-correlated, and the wavelet time delay information of each correlated wavelet pulse, namely, the wavelet time delay information of the receiver trace relative to the reference trace, is obtained. Accordingly, the direct wave and reflected waves are recognized. To evaluate the performance of the algorithm, an algorithm application experiment is conducted for another group of random source signals that were collected by a roadheader under different coal drift conditions. Again, the algorithm processing results are consistent with the single-shot record characteristics of an explosive source. Consequently, the proposed algorithm can satisfy the requirements for engineering exploration and analysis. A comprehensive analysis further demonstrates that the compound interference algorithm is both feasible and effective and that the processed seismic signals can be used for subsequent processing and interpretation.

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Karl, Sebastian, Andreas Zmija, Stefan Richter, Naomi Vogel, Dmitry Malyshev, Adrian Zink, Thilo Michel, Gisela Anton, Joachim von Zanthier, and Stefan Funk. "Comparing different approaches for stellar intensity interferometry." Monthly Notices of the Royal Astronomical Society 512, no. 2 (February 23, 2022): 1722–29. http://dx.doi.org/10.1093/mnras/stac489.

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ABSTRACT Stellar intensity interferometers correlate photons within their coherence time and could overcome the baseline limitations of existing amplitude interferometers. Intensity interferometers do not rely on phase coherence of the optical elements and thus function without high-grade optics and light combining delay lines. However, the coherence time of starlight observed with realistic optical filter bandwidths ($\gt {0.1}\, {\rm nm}$) is usually much smaller than the time resolution of the detection system ($\gt {10}\, {\rm ps}$), resulting in a greatly reduced correlation signal. Reaching high signal-to-noise ratio in a reasonably short measurement time can be achieved in different ways: either by increasing the time resolution, which increases the correlation signal height, or by increasing the photon rate, which decreases statistical uncertainties of the measurement. We present laboratory measurements employing both approaches and directly compare them in terms of signal-to-noise ratio. A high-time-resolution interferometry setup designed for small-to-intermediate-sized optical telescopes and thus lower photon rates (diameters $\lt \,$some metres) is compared to a setup capable of measuring high photon rates, which is planned to be installed at Cherenkov telescopes with dish diameters of $\gt {10}\, {\rm m}$. We use a xenon lamp as a common light source simulating starlight. Both setups measure the expected correlation signal and work at the expected shot-noise limit of statistical uncertainties for measurement times between 10 min and 23 h. We discuss the quantitative differences in the measurement results and give an overview of suitable operation regimes for each of the interferometer concepts.

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Meyer, Michelle, Bronwyn M. Gunn, Delphine C. Malherbe, Karthik Gangavarapu, Asuka Yoshida, Colette Pietzsch, Natalia A. Kuzmina, et al. "Ebola vaccine–induced protection in nonhuman primates correlates with antibody specificity and Fc-mediated effects." Science Translational Medicine 13, no. 602 (July 14, 2021): eabg6128. http://dx.doi.org/10.1126/scitranslmed.abg6128.

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Although substantial progress has been made with Ebola virus (EBOV) vaccine measures, the immune correlates of vaccine-mediated protection remain uncertain. Here, five mucosal vaccine vectors based on human and avian paramyxoviruses provided nonhuman primates with varying degrees of protection, despite expressing the same EBOV glycoprotein (GP) immunogen. Each vaccine produced antibody responses that differed in Fc-mediated functions and isotype composition, as well as in magnitude and coverage toward GP and its conformational and linear epitopes. Differences in the degree of protection and comprehensive characterization of the response afforded the opportunity to identify which features and functions were elevated in survivors and could therefore serve as vaccine correlates of protection. Pairwise network correlation analysis of 139 immune- and vaccine-related parameters was performed to demonstrate relationships with survival. Total GP-specific antibodies, as measured by biolayer interferometry, but not neutralizing IgG or IgA titers, correlated with survival. Fc-mediated functions and the amount of receptor binding domain antibodies were associated with improved survival outcomes, alluding to the protective mechanisms of these vaccines. Therefore, functional qualities of the antibody response, particularly Fc-mediated effects and GP specificity, rather than simply magnitude of the response, appear central to vaccine-induced protection against EBOV. The heterogeneity of the response profile between the vaccines indicates that each vaccine likely exhibits its own protective signature and the requirements for an efficacious EBOV vaccine are complex.

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40

Punjabi, S., K. Muralidhar, and P. K. Panigrahi. "Buoyancy-induced convection in differentially heated superposed two fluid layers in a rectangular cavity." Proceedings of the Institution of Mechanical Engineers, Part C: Journal of Mechanical Engineering Science 222, no. 6 (June 1, 2008): 919–33. http://dx.doi.org/10.1243/09544062jmes351.

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Buoyancy-driven convection in a differentially heated rectangular cavity containing layers of air—water, air—silicone oil, and silicone oil—water has been experimentally studied using laser-interferometry. The cavity has dimensions 32 × 32 mm2 in the vertical plane and length 447 mm. The layer thicknesses were taken to be equal. Experiments are conducted with three cavity temperature differences of 10, 15, and 18 K. The flow field is mapped in the direction parallel to the cavity length using a Mach-Zehnder interferometer. The flow regimes (such as steady two-dimensional, time-dependent, etc.) established in the individual fluid layers were compared with the published regime diagrams of single fluid layer at different Rayleigh numbers. Quantities such as the interface temperature, average Nusselt number, and the temperature profiles were determined from the interferograms. The interface shapes are recorded in the form of shadowgraphs. These results were also looked upon in terms of the coupling mechanism established at the interface. The major conclusions arrived in this study are as follows. In the experiments involving air, the layers were found to be thermally coupled. The unsteadiness in water could however be transmitted to air in the mechanical coupling mode. The presence of silicone oil over water led to mechanical coupling in the sense that the convective field in water was visibly retarded. The interface temperature determined from the experiments matched those from correlations for a single fluid whenever the coupling was thermal in origin. The differences were higher during mechanical coupling. The interface deformation correlated well with the roll movement visible in the fringes.

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Burnett, Deborah L., Peter Schofield, David B. Langley, Jennifer Jackson, Katherine Bourne, Emily Wilson, Benjamin T. Porebski, et al. "Conformational diversity facilitates antibody mutation trajectories and discrimination between foreign and self-antigens." Proceedings of the National Academy of Sciences 117, no. 36 (August 27, 2020): 22341–50. http://dx.doi.org/10.1073/pnas.2005102117.

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Conformational diversity and self-cross-reactivity of antigens have been correlated with evasion from neutralizing antibody responses. We utilized single cell B cell sequencing, biolayer interferometry and X-ray crystallography to trace mutation selection pathways where the antibody response must resolve cross-reactivity between foreign and self-proteins bearing near-identical contact surfaces, but differing in conformational flexibility. Recurring antibody mutation trajectories mediate long-range rearrangements of framework (FW) and complementarity determining regions (CDRs) that increase binding site conformational diversity. These antibody mutations decrease affinity for self-antigen 19-fold and increase foreign affinity 67-fold, to yield a more than 1,250-fold increase in binding discrimination. These results demonstrate how conformational diversity in antigen and antibody does not act as a barrier, as previously suggested, but rather facilitates high affinity and high discrimination between foreign and self.

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42

Werner, Yehudah L., Petar G. Igić, Merav Seifan, and James C. Saunders. "Effects of age and size in the ears of gekkonomorph lizards: middle-ear sensitivity." Journal of Experimental Biology 205, no. 20 (October 15, 2002): 3215–23. http://dx.doi.org/10.1242/jeb.205.20.3215.

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SUMMARY Previous studies of electrophysiological audiograms in gekkonomorph lizards revealed greater sensitivity in adults than in juveniles. We investigated whether this difference, as far as it is affected by the middle ear, is due to animal age or size. The velocity transfer function of the tympanic membrane(TM) was examined using laser interferometry in nine samples: adults of three large gekkonomorph species, adults of three small species (each related to one of the former), and juveniles of the large species, their sizes matching those of the small-species adults. Each transfer function exhibited an inverted `V'or `U' shape, with the velocity of TM motion peaking in the mid-frequency range and becoming poorer at lower and higher frequencies. Among samples,maximum TM velocity correlated with animal length, perhaps because of a damping change in the larger TM. The frequency at maximum velocity negatively correlated with measurements of TM area. Presumably, with a larger TM area,the best frequency shifted downward because of increased middle-ear mass or decreased stiffness. The bandwidth of the transfer function negatively correlated with animal length, being broader in smaller animals and sharper in larger animals. This effect can be attributed to increased mass, decreased damping, or both. Among the middle-ear morphological measurements, the one most closely correlated with body length was the length of the extracolumellar anchorage at the TM. Among the physiological variables investigated, maximum velocity was negatively correlated with the frequency at which it occurred. The dependence of these transfer function variables on animal and ear size was similar, regardless of whether the comparison was among adults of species of different sizes, or among age classes within a species, so that age differences appear to be largely the result of size differences.

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43

Zhou, Hang, Yue Guan, Meng Feng, Yongfeng Fu, Hiroshi Tachibana, and Xunjia Cheng. "Evaluation on Elongation Factor 1 Alpha of Entamoeba histolytica Interaction with the Intermediate Subunit of the Gal/GalNAc Lectin and Actin in Phagocytosis." Pathogens 9, no. 9 (August 27, 2020): 702. http://dx.doi.org/10.3390/pathogens9090702.

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Entamoeba histolytica is the causative agent of amoebiasis. This disease results in 40,000 to 100,000 deaths annually. The pathogenic molecules involved in the invasion of trophozoites had been constantly being clarified. This study explored the role of elongation factor 1 alpha (EF1a) in E. histolytica pathogenicity. Biolayer interferometry binding and pull-down assays suggest that EF1a and intermediate subunit of lectin (Igl) binding are specific. Submembranous distribution of EF1a closely aligns with the localization of Igl, which appear in abundance on membranes of trophozoites. Messenger RNA (mRNA) expression of EF1a is positively correlated with trends in Igl levels after co-incubation with Chinese hamster ovary (CHO) cells in vitro, suggesting a regulatory linkage between these proteins. Erythrophagocytosis assays also imply a role for EF1a in phagocytosis. Finally, EF1a and actin are collocated in trophozoites. These results indicated elongation factor 1a is associated with E. histolytica phagocytosis, and the relationships between EF1a, Igl, and actin are worth further study to better understand the pathogenic process.

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Dravins, Dainis. "Stellar Surface Convection, Line Asymmetries, and Wavelength Shifts." International Astronomical Union Colloquium 170 (1999): 268–77. http://dx.doi.org/10.1017/s0252921100048661.

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AbstractWavelength positions of photospheric absorption lines may be affected by surface convection (stellar granulation). Asymmetries and wavelength shifts originate from correlated velocity and brightness patterns: rising (blueshifted) elements are hot (bright), and convective blueshifts result from a larger contribution of such blueshifted photons than of redshifted ones from the sinking and cooler (darker) gas. For the Sun, the effect is around 300 m s−1, expected to increase in F-type stars, and in giants. Magnetic fields affect convection and induce lineshift variations over stellar activity cycles. A sufficient measuring precision reveals also the temporal variability of line wavelengths (due to the evolution of granules on the stellar surface). A major future development to come from adaptive optics and optical interferometry will be the study of wavelength variations across spatially resolved stars, together with their spatially resolved time variability. Thus, precise radial velocities should soon open up new vistas in stellar atmospheric physics.

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45

Holley, Brian M., Sandor Becz, and Lee S. Langston. "Measurement and Calculation of Turbine Cascade Endwall Pressure and Shear Stress." Journal of Turbomachinery 128, no. 2 (February 1, 2005): 232–39. http://dx.doi.org/10.1115/1.2137744.

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The complex three-dimensional fluid flow on the endwall in an axial flow turbine blade or vane passage has been extensively investigated and reported on in turbomachinery literature. The aerodynamic loss producing mechanisms associated with the endwall flow are still not fully understood or quantitatively predictable. To better quantify wall friction contributions to endwall aerodynamic loss, low Mach number wind tunnel measurement of skin friction coefficients have been made on one endwall of a large scale cascade of high pressure turbine airfoils, at engine operating Reynolds numbers. Concurrently, predictive calculations of the endwall flow shear stress have been made using a computational fluid dynamics (CFD) code. Use of the oil film interferometry skin friction technique is described and applied to the endwall, to measure local skin friction coefficients and shear stress directions on the endwall. These are correlated with previously reported measured local endwall pressure gradients. The experimental results are discussed and compared to the CFD calculations, to answer questions concerning endwall aerodynamic loss predictive ability.

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46

Uribe-Riestra, Gabriela Carolina, Jorge Andrés Ocampo-Bello, Fidel Gamboa, Fernando Mendoza-Santoyo, Carlos Pérez-López, Edgar A. Franco-Urquiza, Marc Preud’homme, Alejandro Castillo-Atoche, and Francis Avilés. "Influence of electrode configuration on impact damage evaluation of self-sensing hierarchical composites." Journal of Intelligent Material Systems and Structures 31, no. 11 (June 2, 2020): 1416–29. http://dx.doi.org/10.1177/1045389x20919979.

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A technique based on the electrical resistance change of a network of carbon nanotubes within a polymer composite was implemented to assess damage caused by low-velocity impact in multiscale hierarchical composites. The influence of the electrode configuration in 100 mm x 100 mm x 1.7 mm plates is addressed. Three electrode configurations are evaluated, namely, a grid on the impacted surface, a grid on the opposite (non-impacted) surface, and through the thickness of the plate. Upon impact, matrix cracking, delamination, and fiber rupture cause disruption and redistribution of the electrical network of carbon nanotubes, whose electrical resistance changes can be correlated with such damage. It is found that the non-impacted surface exhibits a higher fractional change of electrical resistance and hence higher sensitivity to damage. The results obtained using the electrical technique showed a good correlation with damage detected by independent measurements by digital holographic interferometry and ultrasonic inspections.

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47

Hu, Yao, Shaopu Wang, Xuemin Cheng, Chengqiang Xu, and Qun Hao. "Dynamic Deformation Measurement of Specular Surface with Deflectometry and Speckle Digital Image Correlation." Sensors 20, no. 5 (February 26, 2020): 1278. http://dx.doi.org/10.3390/s20051278.

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The deformation measurement of a specular surface is of great importance during the quality inspection and installation of optical elements or wafers, especially those with large apertures. We propose a deflectometry method with speckle digital image correlation (DeSDIC) to realize the dynamic and high-accuracy measurement of the deformation on specular surfaces, with a simple system structure and robustness to noises and environmental vibrations. Random speckle pattern displayed on liquid crystal display is reflected by the original surface under test (SUT), and the distorted pattern is recorded by a camera. This originally distorted pattern is taken as the reference image, and the patterns captured afterwards are digitally correlated with the reference image to calculate the gradient change and deformation of the SUT. The theoretical relationships and an experimental one-step calibration scheme are proposed. Both static and dynamic deformations of a deformable mirror were experimentally measured to demonstrate the feasibility and accuracy of DeSDIC, which is comparable to phase-measuring deflectometry and interferometry.

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48

Afkhamiardakani, Hanieh, and Jean-Claude Diels. "Mode-Locked Fiber Laser Sensors with Orthogonally Polarized Pulses Circulating in the Cavity." Sensors 23, no. 5 (February 24, 2023): 2531. http://dx.doi.org/10.3390/s23052531.

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Intracavity phase interferometry is a powerful phase sensing technique using two correlated, counter-propagating frequency combs (pulse trains) in mode-locked lasers. Generating dual frequency combs of the same repetition rate in fiber lasers is a new field with hitherto unanticipated challenges. The large intensity in the fiber core, coupled with the nonlinear index of glass, result in a cumulative nonlinear index on axis that dwarfs the signal to be measured. The large saturable gain changes in an unpredictable way the repetition rate of the laser impeding the creation of frequency combs with identical repetition rate. The huge amount of phase coupling between pulses crossing at the saturable absorber eliminates the small signal response (deadband). Although there have been prior observation of gyroscopic response in mode-locked ring lasers, to our knowledge this is the first time that orthogonally polarized pulses were used to successfully eliminate the deadband and obtain a beat note.

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Chen, L. M., G. Qiao, and P. Lu. "SURFACE DEFORMATION MONITORING IN PERMAFROST REGIONS OF TIBETAN PLATEAU BASED ON ALOS PALSAR DATA." ISPRS - International Archives of the Photogrammetry, Remote Sensing and Spatial Information Sciences XLII-2/W7 (September 14, 2017): 1509–12. http://dx.doi.org/10.5194/isprs-archives-xlii-2-w7-1509-2017.

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The permafrost region of Qinghai-Tibet Plateau is widely distributed with the freeze/thaw processes that cause surface structural damage. The differential interferometry synthetic aperture radar (DInSAR) can detect large scale surface deformation with high precision, thus can be used to monitor the freeze/thaw processes of frozen soil area. In this paper, the surface deformation pattern of Qinghai-Tibet railway was analyzed by using the PALSAR 1.0 raw data of the ALOS satellite (L band) and 90m resolution SRTM DEM data, with the help of two-pass DInSAR method in GAMMA software, and the differential interferograms and deformation maps were obtained accordingly. Besides, the influence of temperature, topography and other factors on deformation of frozen soil were also studied. The following conclusions were obtained: there is a negative correlation between deformation and temperature, and there is a delay between the deformation change and that of temperature; deformation and elevation are positively correlated; the permafrost deformation is also affected by solar radiation that could form variable amplitude variation.

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50

Vadlamudi, Sai Raja Gopal, Gulshan Kumar Sinha, Atul Srivastava, and Suneet Singh. "Dynamic interaction of growing bubble and microlayer: Need for reconciliation of experiments and theory in flow boiling." Applied Physics Letters 121, no. 12 (September 19, 2022): 124101. http://dx.doi.org/10.1063/5.0101747.

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The bubble growth and its corresponding microlayer dynamics are strongly coupled from the point of bubble inception to its eventual liftoff. This paper discusses the complex and interesting interaction between a bubble and a microlayer through high-speed photography and thin-film interferometry in vertical flow boiling conditions. We analyzed existing force balance models and bubble growth rate models using experimental data. Our analysis revealed that the existing force balance models show severe limitations in predicting bubble dynamics, and the success of models reported by researchers is mainly due to over-parametrization and over-fitting. We show through our experimental results that the movement of the bubble in the flow direction and depletion of the upstream microlayer are strongly correlated with bubble diameter and growth rate. We discuss a non-dimensional approach based on forces acting on the bubble to predict the bubble movement in the flow direction. Furthermore, we report an interesting stage of the bubble ebullition cycle, where the bubble does neither liftoff nor contact the heater surface.

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