Artículos de revistas: "Coherence technique"

1

Palato, Samuel, Hélène Seiler, Parmeet Nijjar, Oleg Prezhdo y Patanjali Kambhampati. "Atomic fluctuations in electronic materials revealed by dephasing". Proceedings of the National Academy of Sciences 117, n.º 22 (14 de mayo de 2020): 11940–46. http://dx.doi.org/10.1073/pnas.1916792117.

Texto completo

Resumen

The microscopic origin and timescale of the fluctuations of the energies of electronic states has a significant impact on the properties of interest of electronic materials, with implication in fields ranging from photovoltaic devices to quantum information processing. Spectroscopic investigations of coherent dynamics provide a direct measurement of electronic fluctuations. Modern multidimensional spectroscopy techniques allow the mapping of coherent processes along multiple time or frequency axes and thus allow unprecedented discrimination between different sources of electronic dephasing. Exploiting modern abilities in coherence mapping in both amplitude and phase, we unravel dissipative processes of electronic coherences in the model system of CdSe quantum dots (QDs). The method allows the assignment of the nature of the observed coherence as vibrational or electronic. The expected coherence maps are obtained for the coherent longitudinal optical (LO) phonon, which serves as an internal standard and confirms the sensitivity of the technique. Fast dephasing is observed between the first two exciton states, despite their shared electron state and common environment. This result is contrary to predictions of the standard effective mass model for these materials, in which the exciton levels are strongly correlated through a common size dependence. In contrast, the experiment is in agreement with ab initio molecular dynamics of a single QD. Electronic dephasing in these materials is thus dominated by the realistic electronic structure arising from fluctuations at the atomic level rather than static size distribution. The analysis of electronic dephasing thereby uniquely enables the study of electronic fluctuations in complex materials.

Los estilos APA, Harvard, Vancouver, ISO, etc.

2

McNutt, Marcia. "Basis of the coherence technique". Nature 343, n.º 6259 (febrero de 1990): 596. http://dx.doi.org/10.1038/343596b0.

Texto completo

Los estilos APA, Harvard, Vancouver, ISO, etc.

3

YAKOVLEV, D. R., A. GREILICH, M. BAYER y I. A. YUGOVA. "ELECTRON SPIN COHERENCE IN SINGLY CHARGED QUANTUM DOTS". International Journal of Modern Physics B 23, n.º 12n13 (20 de mayo de 2009): 2813–25. http://dx.doi.org/10.1142/s0217979209062396.

Texto completo

Resumen

Electron spin coherence is examined experimentally and theoretically in singly charged ( In , Ga ) As / GaAs quantum dots. Time-resolved pump-probe Faraday rotation technique is used to examine fine structure and Zeeman splitting of excitons and resident electrons. Spin dephasing and spin coherence times of resident electrons have been measured in the regime of mode-locking of spin coherency.

Los estilos APA, Harvard, Vancouver, ISO, etc.

4

Qin, Lei, Frank L. Vernon, Christopher W. Johnson y Yehuda Ben‐Zion. "Spectral Characteristics of Daily to Seasonal Ground Motion at the Piñon Flats Observatory from Coherence of Seismic Data". Bulletin of the Seismological Society of America 109, n.º 5 (27 de agosto de 2019): 1948–67. http://dx.doi.org/10.1785/0120190070.

Texto completo

Resumen

Abstract We investigate coherences of seismic data recorded during three years (2015–2017) at the Piñon Flats Observatory (PY) array and a collocated 148 m deep borehole station B084, along with oceanic data from a buoy southwest of the PY array. Seismic and barometric recordings at PY stations are analyzed with a multitaper spectral technique. The coherence of signals from seismic sources is >0.6 at 0.05–8 Hz between closely spaced (<65 m) surface stations and decreases to ∼0.2 in frequency bands in which the wavelengths are smaller than interstation distances. There are several local coherence increases at 1–8 Hz between nearby (<65 m) surface stations, whereas large coherence values between a surface and 148 m deep borehole stations are only present at the secondary microseism (∼0.14 Hz). These points to significant modification of seismic recordings in the top crust, and those continual near‐surface failures might produce shallow rapidly attenuating signals at surface stations. Incoherent local atmospheric effects induce incoherent seismic signals in low‐ and high‐frequency ranges through different coupling mechanisms. Between 0.003 and 0.05 Hz, atmospheric loadings generate ground tilts that contaminate the two horizontal seismic recordings and decrease their coherence, whereas the vertical component is less affected. At 1–8 Hz, coupling of atmospheric pressure with surface structures transmits incoherent signals into the ground, degrading the seismic coherence in all three components. The two horizontal coherences show seasonal variations with extended coherent frequency bands in winter and spring, likely to be produced by seasonal variations in microseisms and local ground tilts. The coherences also contain high anomalies between 2 and 4 Hz resulting from anthropogenic activities. The results provide useful information on instrument characteristics and variations in the shallow crustal response to earthquakes, seasonal and ambient sources of seismic energy, along with atmospheric pressure–temperature changes and anthropogenic activities.

Los estilos APA, Harvard, Vancouver, ISO, etc.

5

DOLAN, KEVIN T. "SURROGATE ANALYSIS OF MULTICHANNEL DATA WITH FREQUENCY DEPENDANT TIME LAG". Fluctuation and Noise Letters 04, n.º 01 (marzo de 2004): L75—L81. http://dx.doi.org/10.1142/s0219477504001677.

Texto completo

Resumen

Recently a new technique for generating linear surrogates of multichannel data was introduced. This technique, referred to as the coherent digitally filtered surrogate method, preserves both the individual power spectra, and the coherence function, of the original data. This method is somewhat limited in that it can only be applied to multichannel data in which the cross-spectrum is real. We present here an alteration to this algorithm that can be used to test any linear-correlation model, with arbitrary complex cross-spectra. This is of particular interest for experiments in which two channels are coupled with some time lag, and it is necessary to determine if the coupling is linear. We also demonstrate that this algorithm can be used along with the synchronization to provide a much better estimate for the degree of phase-locking between two signals than the coherence analysis techniques traditionally used in neuroscience.

Los estilos APA, Harvard, Vancouver, ISO, etc.

6

Lokhande, Prakash. "A NEW AND MODERN DIGNOSTIC TECHNIQUE: SWEPT-SOURCE OPTICAL COHERENCE TOMOGRAPHY (SS-OCT)". CODS Journal of Dentistry 5, n.º 2 (2013): 31–33. http://dx.doi.org/10.5005/cods-5-2-31.

Texto completo

Resumen

ABSTRACT Innovative technique has been introduced in the field of dentistry for the purpose of diagnosis and treatment. Technologies like laser, composite curing techniques, optical imaging have been utilized in the field of dentistry. OCT(optical coherence tomography) is a recent. technique which creates cross-sectional high resolution images. SS-OCT(Swept -Source optical coherence tomography) is a variant of optical coherence tomography, which provides instant imaging with high resolution, non-invasive and ease of handling. This article provides a overview of Swept -Source OCT and its application in the field of dentistry.

Los estilos APA, Harvard, Vancouver, ISO, etc.

7

Abdushkour, Hesham, Toufique A. Soomro, Ahmed Ali, Fayyaz Ali Jandan, Herbert Jelinek, Farida Memon, Faisal Althobiani, Saleh Mohammed Ghonaim y Muhammad Irfan. "Enhancing fine retinal vessel segmentation: Morphological reconstruction and double thresholds filtering strategy". PLOS ONE 18, n.º 7 (19 de julio de 2023): e0288792. http://dx.doi.org/10.1371/journal.pone.0288792.

Texto completo

Resumen

Eye diseases such as diabetic retinopathy are progressive with various changes in the retinal vessels, and it is difficult to analyze the disease for future treatment. There are many computerized algorithms implemented for retinal vessel segmentation, but the tiny vessels drop off, impacting the performance of the overall algorithms. This research work contains the new image processing techniques such as enhancement filters, coherence filters and binary thresholding techniques to handle the different color retinal fundus image problems to achieve a vessel image that is well-segmented, and the proposed algorithm has improved performance over existing work. Our developed technique incorporates morphological techniques to address the center light reflex issue. Additionally, to effectively resolve the problem of insufficient and varying contrast, our developed technique employs homomorphic methods and Wiener filtering. Coherent filters are used to address the coherence issue of the retina vessels, and then a double thresholding technique is applied with image reconstruction to achieve a correctly segmented vessel image. The results of our developed technique were evaluated using the STARE and DRIVE datasets and it achieves an accuracy of about 0.96 and a sensitivity of 0.81. The performance obtained from our proposed method proved the capability of the method which can be used by ophthalmology experts to diagnose ocular abnormalities and recommended for further treatment.

Los estilos APA, Harvard, Vancouver, ISO, etc.

8

Bennett, Michael y Simon Christie. "Application of a Doppler optical coherence technique to boundary layer sounding". Meteorologische Zeitschrift 16, n.º 5 (26 de octubre de 2007): 469–77. http://dx.doi.org/10.1127/0941-2948/2007/0219.

Texto completo

Los estilos APA, Harvard, Vancouver, ISO, etc.

9

Li, Yandong, Wenkai Lu, Huanqin Xiao, Shanwen Zhang y Yanda Li. "Dip-scanning coherence algorithm using eigenstructure analysis and supertrace technique". GEOPHYSICS 71, n.º 3 (mayo de 2006): V61—V66. http://dx.doi.org/10.1190/1.2194899.

Texto completo

Resumen

The eigenstructure-based coherence algorithms are robust to noise and able to produce enhanced coherence images. However, the original eigenstructure coherence algorithm does not implement dip scanning; therefore, it produces less satisfactory results in areas with strong structural dips. The supertrace technique also improves the coherence algorithms’ robustness by concatenating multiple seismic traces to form a supertrace. In addition, the supertrace data cube preserves the structural-dip information that is contained in the original seismic data cube; thus, dip scanning can be performed effectively using a number of adjacent supertraces. We combine the eigenstructure analysis and the dip-scanning supertrace technique to obtain a new coherence-estimation algorithm. Application to the real data set shows that the new algorithm provides good coherence estimates in areas with strong structural dips. Furthermore, the algorithm is computationally efficient because of the small covariance matrix [Formula: see text] used for the eigenstructure analysis.

Los estilos APA, Harvard, Vancouver, ISO, etc.

10

Nagpal, Manish y Gujarat India. "Optical Coherence Tomography Angiography". US Ophthalmic Review 11, n.º 2 (2018): 91. http://dx.doi.org/10.17925/usor.2018.11.2.91.

Texto completo

Resumen

Optical coherence tomography angiography (OCTA) is a new revolutionary non-invasive imaging modality, built on the platform of optical coherence tomography (OCT). This technique works on the principle of ‘decorrelation’ and is still a nascent technology in its infancy with tremendous potential applicability for diagnosing retinal and choroidal vascular diseases. Its non-invasive nature, and the ability to generate images of retinal and choroidal vasculature, allows it to replace and/or supplement the current angiographic gold standards, fluorescein angiography (FA) and indocyanine green angiography (ICGA), if not in all but certainly in most retinal and choroidal pathologies. Still, there exists a major challenge in terms of its wide-scale availability, equipment and processing techniques, presence of artifacts, limitations of imaging capability, and lack of common vocabulary among retinal specialists for interpretation. In this review we intend to describe this novel technique by highlighting its key features, and comparing it with FA and ICGA. We will also discuss its applicability in various clinical scenarios such as diabetic retinopathy, age-related macular degeneration, retinal venous occlusion, choroiditis, and in routine practice. Further studies are needed to more definitively determine OCTA’s utility in the clinical setting and to establish if this technology may offer a non-invasive option of visualizing the retinal vasculature in detail.

Los estilos APA, Harvard, Vancouver, ISO, etc.

11

James, Daniel F. V. "The effect of spatial coherence of sources on synthetic aperture mapping". International Astronomical Union Colloquium 131 (1991): 10–14. http://dx.doi.org/10.1017/s0252921100012999.

Texto completo

Resumen

The interferometric mapping of astronomical objects relies on the van-Cittert Zernike theorem, one of the major results of the theory of partially coherent light [see, Bom and Wolf (1980), chapter 10]. This theorem states that the degree of spatial coherence of the field from a distant spatially incoherent source is proportional to the Fourier transform of the intensity distribution across the source. Measurement of the degree of spatial coherence, by, for example, measuring the visibility of interference fringes, allows the object to be mapped by making an inverse Fourier transform. (For a full description of this technique see Thompson, Moran and Swenson, 1986.)In this paper I present a summary of the results an investigation into what happens when the distant source is not spatially coherent (James, 1990). Using a heuristic model of a spherically symmetric partially coherent source, an analytic expression for the error in the measurement of the effective radius, expressed as a function of coherence area, can be obtained.

Los estilos APA, Harvard, Vancouver, ISO, etc.

12

Barreiro, J. C. y J. Ojeda-Castañeda. "Degree of coherence: a lensless measuring technique". Optics Letters 18, n.º 4 (15 de febrero de 1993): 302. http://dx.doi.org/10.1364/ol.18.000302.

Texto completo

Los estilos APA, Harvard, Vancouver, ISO, etc.

13

Vaidya, P. G. "Applications of the trans‐spectral coherence technique". Journal of the Acoustical Society of America 98, n.º 5 (noviembre de 1995): 2951. http://dx.doi.org/10.1121/1.414094.

Texto completo

Los estilos APA, Harvard, Vancouver, ISO, etc.

14

Yan, Xin y Yuanyuan Wang. "A submatrix spatial coherence approach to minimum variance beamforming combined with sign coherence factor for coherent plane wave compounding". Technology and Health Care 30 (25 de febrero de 2022): 11–25. http://dx.doi.org/10.3233/thc-228002.

Texto completo

Resumen

BACKGROUND: The coherent plane wave compounding (CPWC) is a promising technique to enhance the imaging quality while maintaining the high frame rate in the plane wave ultrasound imaging. Recently, the spatial-coherence-based method has been specially designed to process echo matrix required by the minimum variance (MV) method. OBJECTIVE: In this paper, a novel beamforming method that integrates the submatrix-spatial-coherence-based MV with the sign coherence factor (SCF) is proposed to further improve the imaging quality. METHOD: The submatrix smoothing technique is modified to smooth and de-correlate signals of the receiving array dimension. Then, the SCF is used to modify the input vector of the beamformer, which can reduce side lobe noises with almost no increase in the amount of calculation. Simulation, phantom, in vivo, and sound velocity error experiments have been performed to verify the superiority of the proposed beamformer. RESULTS: The imaging results show that the proposed approach performs better in the imaging resolution and contrast compared to the traditional CPWC method. CONCLUSION: The robustness of the proposed method is enhanced, and the over-suppression phenomenon can be alleviated, which is a phenomenon that occurs in the original spatial-coherence and SCF methods.

Los estilos APA, Harvard, Vancouver, ISO, etc.

15

Arvianto, Faizal, Deden Ahmad Supendi y Tanti Agustiani. "HUBUNGAN ANTARA MINAT MENULIS DENGAN PENGUASAAN PERANTI KOHESI DAN KOHERENSI DALAM PEMBELAJARAN BAHASA INDONESIA PADA SISWA KELAS X SMK SEKOTA SUKABUMI TAHUN PELAJARAN 2016/2017 (CORRELATION BETWEEN THE INTEREST IN WRITING AND THE MASTERY OF COHESION AND COHERENCE TOOLS IN INDONESIAN LANGUAGE LEARNING OF CLASS X VOCATIONAL HIGH SCHOOL IN SUKABUMI CITY)". Metalingua: Jurnal Penelitian Bahasa 16, n.º 1 (2 de octubre de 2018): 7. http://dx.doi.org/10.26499/metalingua.v16i1.127.

Texto completo

Resumen

This study aims to determine whether or not the relationship between interest in writing with the mastery of tools of cohesion and coherence in learning Indonesian language in the students of class X SMK Se-Kota Sukabumi. Interest is a great desire for something. Interests can affect the quality of student learning outcomes in accordance with the particular field of study. This makes researchers interested in conducting research on the relationship between interest in writing with the mastery of tools of cohesion and coherence considering the tools of cohesion and coherence is an important part in the formation of discourse. This study is devoted to the interest in writing and mastery of cohesion and coherence tools in Indonesian language learning, because in Indonesian language learning writing skills and tools of cohesion and coherence are widely studied. This research uses quantitative research method with correlational approach. The researcher collected data with questionnaire instruments for interest data of menuls and multiple choice test instruments for cohesion and coherency tool mastery data. Determination of the sample using random sampling technique because the sampling was chosen randomly without considering the strata in the population. Data analysis technique used product moment correlation technique with 5% significance level. Based on the results of data analysis revealed that interest in writing students average-average 74.8% and well-categorized. Mastery of cohesion tools and student coherence averaging 70% of good categorized. Based on the results of data analysis of each variable stated that there is a positive relationship between the interest of writing with the mastery of tools of cohesion and coherence in students of class X SMK Se-Kota Sukabumi in learning Indonesian language lesson 2016/2017. From the calculation results there is a correlation of 0.290 and included in the correlation coefficient of low category. From the results of t-test significance, there is a score of t count of 3.248> from the table t score of 1.980. So it can be concluded that there is a positive and significant relationship between the interest of writing with the mastery of tools of cohesion and coherence in the students of class X SMK Se-Kota Sukabumi academic year 2016/2017.

Los estilos APA, Harvard, Vancouver, ISO, etc.

16

Li, Meng-Lin, Sheng-Wen Huang, Kutay Üstüner y Pai-Chi Li. "Adaptive Imaging Using an Optimal Receive Aperture Size". Ultrasonic Imaging 27, n.º 2 (abril de 2005): 111–27. http://dx.doi.org/10.1177/016173460502700205.

Texto completo

Resumen

Sidelobe contribution from off-axis targets degrades image quality in a coherent array imaging system. In ultrasound imaging, focusing errors resulting from sound-velocity inhomogeneities in human tissue — also known as phase aberrations — reduce the coherence of the received signals and elevate the sidelobe level. This paper proposes an adaptive receive-aperture technique based on thresholding of the coherence factor (CF). The CF describes the coherence of the received array signals and can be used as an index of focusing quality. This paper demonstrates that thresholding of the CF allows the mainlobe-dominated signals to be distinguished from the sidelobe-dominated signals, after which the receive-aperture size at each imaging position can be optimally determined so as to enhance the mainlobe-dominated signals and suppress the sidelobe-dominated signals. Thus, image quality degradation resulting from sound-velocity inhomogeneities can be reduced. Simulations and measured ultrasound data are used to evaluate the efficacy of the proposed technique. The characteristics of the proposed technique including the effects of the signal-to-noise ratio (SNR) and the transmit focal depth, and speckle reduction are discussed. The proposed technique is also compared with the parallel adaptive receive compensation algorithm and shown to produce a better improvement in image quality.

Los estilos APA, Harvard, Vancouver, ISO, etc.

17

Su, Zhe y Chun Fan. "Adaptive Weighted Coherence Ratio Approach for Industrial Explosion Damage Mapping: Application to the 2015 Tianjin Port Incident". Remote Sensing 16, n.º 22 (14 de noviembre de 2024): 4241. http://dx.doi.org/10.3390/rs16224241.

Texto completo

Resumen

The 2015 Tianjin Port chemical explosion highlighted the severe environmental and structural impacts of industrial disasters. This study presents an Adaptive Weighted Coherence Ratio technique, a novel approach for assessing such damage using synthetic aperture radar (SAR) data. Our method overcomes limitations in traditional techniques by incorporating temporal and spatial weighting factors—such as distance from the explosion epicenter, pre- and post-event intervals, and coherence quality—into a robust framework for precise damage classification. This approach effectively captures extreme damage scenarios, including crater formation in inner blast zones, which are challenging for conventional coherence scaling. Through a detailed analysis of the Tianjin explosion, we reveal asymmetric damage patterns influenced by high-rise buildings and demonstrate the method’s applicability to other industrial disasters, such as the 2020 Beirut explosion. Additionally, we introduce a technique for estimating crater dimensions from coherence profiles, enhancing assessment in severely damaged areas. To support structural analysis, we model air pollutant dispersal using HYSPLIT simulations. This integrated approach advances SAR-based damage assessment techniques, providing rapid reliable classifications applicable to various industrial explosions, aiding disaster response and recovery planning.

Los estilos APA, Harvard, Vancouver, ISO, etc.

18

Setya Nugraha, Alfian y Alfaza Safira. "ANALISIS KOHESI dan KOHEREN PADA WACANA CERPEN KEUTAMAAN SEDEKAH KARYA HABIBURRAHMAN EL SHIRAY". Jurnal Disastri (Jurnal Pendidikan Bahasa dan Sastra Indonesia) 1, n.º 01 (26 de agosto de 2019): 7–15. http://dx.doi.org/10.33752/disastri.v1i01.477.

Texto completo

Resumen

this study will analyze cohesion and coherence in short stories entitled the primacy of alms the work of Habiburrahman El Shirazy to find out the use of chesion and coherence in the short stor. In this case cohesion and coherence are one of the important compenents in the formation of a dicourse or text. This study will discuss lexical cohesion and gramaical cohesion and coherent. This research hopes that better writing can be useful for the reader. With that reader can take the mandate conveyed by the author. The menthod of qualitative description is seen in terms of words, phrase sentences or paragraphs. The technique used is to read and take notes.

Los estilos APA, Harvard, Vancouver, ISO, etc.

19

Vasudevan, Kris, William G. Wilson y William G. Laidlaw. "Simulated annealing statics computation using an order‐based energy function". GEOPHYSICS 56, n.º 11 (noviembre de 1991): 1831–39. http://dx.doi.org/10.1190/1.1442996.

Texto completo

Resumen

The residual statics problem in seismic data analysis is treated by introducing an optimization function that emphasizes the coherence of neighboring common depth point (CDP) gathers within a nonlinear simulated annealing technique. This optimization criterion contrasts with stack power optimization which only considers the coherence between traces within a single CDP. Emphasizing coherence between CDPs removes many of the phase space degeneracies that result from stack‐power based optimization techniques. We have applied the method to both synthetic and real data sets, and initial results display significant improvement over the input data in the coherence of reflections, even in structurally complex areas.

Los estilos APA, Harvard, Vancouver, ISO, etc.

20

Wiyatasari, Reny y Mahardita Hideko. "Koherensi pada Video Blog Berbahasa Jepang". IZUMI 11, n.º 2 (14 de noviembre de 2022): 135–42. http://dx.doi.org/10.14710/izumi.11.2.135-142.

Texto completo

Resumen

The aim of this research is to describe the elements of coherence in the discourse of Japanese video blog. The data of this research is taken from a video blog entitled ‘[Chōkai | Nihongo Kaiwa] Daigaku No Tomodachi to Hanasu Toki <Nihongo Joukyuushamuke>’ uploaded to YouTube on January 22, 2020. The data retrieval method used the referral method, using the tapping technique as its advanced technique. Furthermore, in the data analysis phase, using the ‘Agih’ method with the direct element sharing techniques. Then in presenting the data, using informal presentation methods.The results showed that there were 5 coherence data that showed interconnected discourse, seen from the use of cohesion markers. That way, the five datas can represent discourse coherence.

Los estilos APA, Harvard, Vancouver, ISO, etc.

21

Hyde, Milo. "Controlling the Spatial Coherence of an Optical Source Using a Spatial Filter". Applied Sciences 8, n.º 9 (26 de agosto de 2018): 1465. http://dx.doi.org/10.3390/app8091465.

Texto completo

Resumen

This paper presents the theory for controlling the spectral degree of coherence via spatial filtering. Starting with a quasi-homogeneous partially coherent source, the cross-spectral density function of the field at the output of the spatial filter is found by applying Fourier and statistical optics theory. The key relation obtained from this analysis is a closed-form expression for the filter function in terms of the desired output spectral degree of coherence. This theory is verified with Monte Carlo wave-optics simulations of spatial coherence control and beam shaping for potential use in free-space optical communications and directed energy applications. The simulated results are found to be in good agreement with the developed theory. The technique presented in this paper will be useful in applications where coherence control is advantageous, e.g., directed energy, free-space optical communications, remote sensing, medicine, and manufacturing.

Los estilos APA, Harvard, Vancouver, ISO, etc.

22

Mehrotra, S. C. "Collision Induced Transitions of Molecular Systems of Interstellar Interest through Microwave Pulse Techniques". Symposium - International Astronomical Union 120 (1987): 43–46. http://dx.doi.org/10.1017/s0074180900153768.

Texto completo

Resumen

Microwave pulse techniques have proved to be very useful to obtain informations about coherence decay rates and population transfer rates in gas phase. the coherence decay rates have been measured by a technique which involves the detection of the transient emission signal of the molecular sample following an intense microwave pulse. the (π-τ-π/2) pulse sequence technique has been used to extract informations about population transfer rates. the experimental results on 1-doublet transitions of HCN and HCCCN perturbed by H2,D2and He are given. the theoretical results obtained from the perturbative approach to collision dynamics have also been computed, and compared with the experimental results. for the 1-doublet transitions of HCN, the population decay rates have found to be considerably less than the corresponding coherence decay rates.

Los estilos APA, Harvard, Vancouver, ISO, etc.

23

Cao, Chun Yan, Shui Dong Xiong, Zheng Liang Hu y Yong Ming Hu. "Suppression of Double Rayleigh Scattering Induced Coherent Noise in a Remote Fiber Sensor System Using PGC Technique". Advanced Materials Research 571 (septiembre de 2012): 185–89. http://dx.doi.org/10.4028/www.scientific.net/amr.571.185.

Texto completo

Resumen

Double Rayleigh scattering (DRS) induces coherent noises in remotely interrogated optical fiber sensor systems especially when high coherence laser sources are used. Phase generation carried (PGC) technique has been used in optical fiber sensors to overcome bias induced signal fading and eliminated incoherent noises at low frequency. In this paper we demonstrated that PGC technique can also suppress DRS induced coherent noises. In an experimental setup with total 50-km input and output lead fibers, we achieved maximum 7dB of intensity noise suppression and maximum 10dB of phase noise suppression. With PGC technique, DRS induced phase noise has been suppressed to the sensor self-noise level.

Los estilos APA, Harvard, Vancouver, ISO, etc.

24

Lin, Rongzhi y Mauricio D. Sacchi. "Separation of simultaneous sources acquired with a high blending factor via coherence pass robust Radon operators". GEOPHYSICS 85, n.º 3 (1 de mayo de 2020): V269—V282. http://dx.doi.org/10.1190/geo2019-0692.1.

Texto completo

Resumen

We have developed an iterative method for simultaneous source separation (deblending) suitable for data acquired with a high blending factor. Our technique adopts the robust sparse Radon transform to define a coherence pass operator that is used in conjunction with the steepest-descent method to guarantee solutions that honor simultaneous source records. We find that an important improvement in convergence is attainable when the coherence pass projection is derived from a robust sparse Radon transform. This is a consequence of having an iterative deblending algorithm that applies intense denoising to erratic blending noise in its initial iterations. The coherence pass robust Radon operator acts as a data projection operator that preserves coherent signals and annihilates incoherent blending noise right from the start of the iterative process. We compare the algorithm with its nonrobust version and find that a coherence pass nonrobust Radon operator will only achieve high-quality results for acquisitions with a moderate blending factor.

Los estilos APA, Harvard, Vancouver, ISO, etc.

25

Aristama, Dio, Rokhmat Basuki y Bambang Djunaidi. "PENGGUNAAN PERANTI KOHESI DAN KOHERENSI PADA NASKAH DRAMA KARANGAN SISWA KELAS VIII SMPN 7 KOTA BENGKULU". Jurnal Ilmiah KORPUS 2, n.º 1 (6 de agosto de 2018): 8–21. http://dx.doi.org/10.33369/jik.v2i1.5544.

Texto completo

Resumen

The purpose of this study is to see and describe how the use of cohesion and coherency tools in the drama text of students of class VIII SMPN 7 Kota Bengkulu. The method used in this research is descriptive qualitative method. The data in this research is in the form of drama written by students. The source of this research data is the inter-faith dialogue in the student's drama script. Technique of collecting data using documentation method. Data analysis technique in this research is done through steps. Test the validity of the data used is credibility test done by increasing persistence, supervisors during the process of guidance takes place, and discussion with colleagues. The result of the research is found that the cohesion device contained in the student's drama script is pronoun (pronoun) consisting of (1) the first single person pronoun who is saya, and Aku (2) the first person plural pronomina kami, and kita, (3) The second individual pronoun is kamu, and kau (4) the pronoun of your second plural, (5) the singular third person pronoun dia, (6) the third person's plural pronouns they are, (7) the guidance pronoun there, that, and this, (8) The pronouns are mu, ku, and dia. (9) Substitution devices are so, that, that, and the same. (10) The ellipsis device contains the removed part. (11) The conjunction device consists of the adversative conjunction that is but, the casual conjunction that is because, the coordinating conjunction adalah and / or, the subordinate conjunction is that, if, the correlative conjunction is either / or, the temporal conjunction is before. (12) Lexical devices consist of repetition (repetition) following the race, synonyms or maternal / parent, antonym or friendlike and hostile counterparts. There are ten types of means of coherence in the student's drama text are: (1) Coherence means of addition, and, also, (2) Coherence means of repetition or repetition of speech, (3) Coherence means of contrast or contradiction ie but (4) Coherence means (5) Coherence means the result or conclusion is so, (7) Synonym or synonyms coefficient of the word mother / parent, (8) Coherence of suppression means that even , (9) The means of coherence of causal relations is due, and (10) The time coherence means is that time. With the intensity of the use of means of coherence different from each other.Keywords: cohesion, coherence, drama by student essay

Los estilos APA, Harvard, Vancouver, ISO, etc.

26

S, Alqahtani Saeed, Toufique A. Soomro, Nisar Ahmed Jandan, Ahmed Ali, Muhammad Irfan, Saifur Rahman, Waleed A. Aldhabaan, Abdulrahman Samir Khairallah y Ismail Abuallut. "Impact of Retinal Vessel Image Coherence on Retinal Blood Vessel Segmentation". Electronics 12, n.º 2 (12 de enero de 2023): 396. http://dx.doi.org/10.3390/electronics12020396.

Texto completo

Resumen

Retinal vessel segmentation is critical in detecting retinal blood vessels for a variety of eye disorders, and a consistent computerized method is required for automatic eye disorder screening. Many methods of retinal blood vessel segmentation are implemented, but these methods only yielded accuracy and lack of good sensitivity due to the coherence of retinal blood vessel segmentation. Another main factor of low sensitivity is the proper technique to handle the low-varying contrast problem. In this study, we proposed a five-step technique for assessing the impact of retinal blood vessel coherence on retinal blood vessel segmentation. The proposed technique for retinal blood vessels involved four steps and is known as the preprocessing module. These four stages of the pre-processing module handle the retinal image process in the first stage, uneven illumination and noise issues using morphological operations in the second stage, and image conversion to grayscale using principal component analysis (PCA) in the third step. The fourth step is the main step of contributing to the coherence of retinal blood vessels using anisotropic diffusion filtering and testing their different schemes and get a better coherent image on the optimized anisotropic diffusion filtering. The last step included double thresholds with morphological image reconstruction techniques to produce a segmented image of the vessel. The performances of the proposed method are validated on the publicly available database named DRIVE and STARE. Sensitivity values of 0.811 and 0.821 on STARE and DRIVE respectively meet and surpass other existing methods, and comparable accuracy values of 0.961 and 0.954 on STARE and DRIVE databases to existing methods. This proposed new method for retinal blood vessel segmentations can help medical experts diagnose eye disease and recommend treatment in a timely manner.

Los estilos APA, Harvard, Vancouver, ISO, etc.

27

Sassaroli, Angelo, Kristen Tgavalekos y Sergio Fantini. "The meaning of “coherent” and its quantification in coherent hemodynamics spectroscopy". Journal of Innovative Optical Health Sciences 11, n.º 06 (noviembre de 2018): 1850036. http://dx.doi.org/10.1142/s1793545818500360.

Texto completo

Resumen

We have recently introduced a new technique, coherent hemodynamics spectroscopy (CHS), which aims at characterizing a specific kind of tissue hemodynamics that feature a high level of covariation with a given physiological quantity. In this study, we carry out a detailed analysis of the significance of coherence and phase synchronization between oscillations of arterial blood pressure (ABP) and total hemoglobin concentration ([Hbt]), measured with near-infrared spectroscopy (NIRS) during a typical protocol for CHS, based on a cyclic thigh cuff occlusion and release. Even though CHS is based on a linear time invariant model between ABP (input) and NIRS measurands (outputs), for practical reasons in a typical CHS protocol, we induce finite “groups” of ABP oscillations, in which each group is characterized by a different frequency. For this reason, ABP (input) and NIRS measurands (output) are not stationary processes, and we have used wavelet coherence and phase synchronization index (PSI), as a metric of coherence and phase synchronization, respectively. PSI was calculated by using both the wavelet cross spectrum and the Hilbert transform. We have also used linear coherence (which requires stationary process) for comparison with wavelet coherence. The method of surrogate data is used to find critical values for the significance of covariation between ABP and [Hbt]. Because we have found similar critical values for wavelet coherence and PSI by using five of the most used methods of surrogate data, we propose to use the data-independent Gaussian random numbers (GRNs), for CHS. By using wavelet coherence and wavelet cross spectrum, and GRNs as surrogate data, we have found the same results for the significance of coherence and phase synchronization between ABP and [Hbt]: on a total set of 20 periods of cuff oscillations, we have found 17 coherent oscillations and 17 phase synchronous oscillations. Phase synchronization assessed with Hilbert transform yielded similar results with 14 phase synchronous oscillations. Linear coherence and wavelet coherence overall yielded similar number of significant values. We discuss possible reasons for this result. Despite the similarity of linear and wavelet coherence, we argue that wavelet coherence is preferable, especially if one wants to use baseline spontaneous oscillations, in which phase locking and coherence between signals might be only temporary.

Los estilos APA, Harvard, Vancouver, ISO, etc.

28

Tahara, Hirokazu y Yoshihiko Kanemitsu. "(Invited, Digital Presentation) Photocurrent Detection of Cooperative Exciton Quantum Interference in Nanocrystal Thin Films". ECS Meeting Abstracts MA2022-02, n.º 20 (9 de octubre de 2022): 922. http://dx.doi.org/10.1149/ma2022-0220922mtgabs.

Texto completo

Resumen

Colloidal semiconductor quantum dots (QDs) are excellent materials for studying the photophysics of exciton complexes such as biexcitons, triexcitons, and charged excitons (trions). Dynamics of exciton complexes usually determines the performance of optoelectronic devices [1]. For example, trions reduce the optical gain threshold in QD lasers and multiexcitons increase photon-to-current conversion efficiencies via carrier multiplication processes in QD solar cells. In addition, unconventional properties of multiexcitons emerge in coherent processes in QD systems. We recently discovered the high-frequency coherent oscillations with integer multiples of the exciton resonance frequency, which is called multiexciton harmonic quantum coherence [2,3]. The multiexciton coherent properties have been investigated using optical methods. However, to clarify their roles in optoelectronic devices, it is necessary to conduct the electrical detection of multiexciton coherence. Here, we performed photocurrent detection of exciton quantum interference signals in QD thin films. The samples used in this study were closely packed PbS QD thin films. The QD films were sandwiched between the electron and hole transport layers to extract photogenerated carriers. Multiexcitons were generated by phase-locked femtosecond laser pulses, and then their photocurrent quantum interference signals were measured by using a quantum interference technique [4]. The photocurrent interference signal in the weak excitation shows a single sinusoidal oscillation originating from single excitons, while the interference signal changes to the profile involving multiple sinusoidal oscillations with increasing excitation intensity. This means that the multiexciton quantum coherence exhibiting harmonic oscillations is successfully detected in a photocurrent technique [5]. Furthermore, the amplitudes of harmonic quantum coherent signals in coupled QDs are significantly larger than those in isolated QDs. We clarified that the enhancement of the amplitudes is caused by cooperative processes in coupled QDs, where excitons in adjacent QDs interact with each other through their inter-QD coherent coupling. This cooperative effect can provide a new way to use inter-QD coherent coupling in advanced optoelectronic applications, e.g., amplifiers of coherent signals. Part of this work was supported by JSPS KAKENHI (JP19H05465 and JP22H01990) and JST CREST (JPMJCR21B4). References [1] Kanemitsu, Y. Trion dynamics in lead halide perovskite nanocrystals. J. Chem. Phys. 151, 170902 (2019). [2] Tahara, H.; Sakamoto, M.; Teranishi, T.; Kanemitsu, Y. Harmonic Quantum Coherence of Multiple Excitons in PbS/CdS Core-Shell Nanocrystals. Phys. Rev. Lett. 119, 247401 (2017). [3] Tahara, H.; Sakamoto, M.; Teranishi, T.; Kanemitsu, Y. Quantum coherence of multiple excitons governs absorption cross-sections of PbS/CdS core/shell nanocrystals. Nat. Commun. 9, 3179 (2018). [4] Tahara, H.; Kanemitsu, Y. Quantum Interference Measurements and Their Application to Analysis of Ultrafast Photocarrier Dynamics in Semiconductor Solar Cell Materials. Adv. Quantum Technol. 3, 1900098 (2020). [5] Tahara, H.; Sakamoto, M.; Teranishi, T.; Kanemitsu, Y. Collective enhancement of quantum coherence in coupled quantum dot films. Phys. Rev. B 104, L241405 (2021).

Los estilos APA, Harvard, Vancouver, ISO, etc.

29

Sabuncu, Metin y Hakan Özdemir. "Recognition of Weave Patterns of Striped Fabrics Using Optical Coherence Tomography". Fibres and Textiles in Eastern Europe 26, n.º 3(129) (30 de junio de 2018): 98–103. http://dx.doi.org/10.5604/01.3001.0011.7311.

Texto completo

Resumen

The recognition of woven fabric repeat by conventional techniques is labour intensive. In general, woven fabric repeat identification is accomplished automatically by employing complex algorithms and techniques. These algorithms may, however, occasionally fail, especially when dealing with high complexity texture patterns, structures, figures and colours. Optical coherence tomography (OCT) has the capability of taking high resolution images via contactless measurements. In this paper we apply the spectral domain optical coherence tomography imaging technique for identifying striped woven fabric repeat automatically. OCT scans corresponding to four different fabrics, from which the weave matrixes were recognised, are reported in this study. Automatic identification of weave patterns of striped fabrics was accomplished non-destructively by employing optical coherence tomography.

Los estilos APA, Harvard, Vancouver, ISO, etc.

30

Rude, S. "Optical coherence tomography (OCT) as a radiographic technique". Applied Optics 34, n.º 32 (10 de noviembre de 1995): Z1. http://dx.doi.org/10.1364/ao.34.0000z1.

Texto completo

Los estilos APA, Harvard, Vancouver, ISO, etc.

31

King, Willie Tan. "Technique for Reduction of Coherence Function Bias Error". IEEE Transactions on Nuclear Science 32, n.º 1 (1985): 1041–43. http://dx.doi.org/10.1109/tns.1985.4336994.

Texto completo

Los estilos APA, Harvard, Vancouver, ISO, etc.

32

Rolland, Jannick P., Panomsak Meemon, Supraja Murali, Kevin P. Thompson y Kye-sung Lee. "Gabor-based fusion technique for Optical Coherence Microscopy". Optics Express 18, n.º 4 (4 de febrero de 2010): 3632. http://dx.doi.org/10.1364/oe.18.003632.

Texto completo

Los estilos APA, Harvard, Vancouver, ISO, etc.

33

Haouchine, B. y A. Gaudric. "Technique et interprétation de l'« optical coherence tomography »". EMC - Ophtalmologie 5, n.º 2 (enero de 2008): 1–12. http://dx.doi.org/10.1016/s0246-0343(08)29994-6.

Texto completo

Los estilos APA, Harvard, Vancouver, ISO, etc.

34

Andrews, J. T., H. S. Patel y P. K. Gupta. "A Novel Scanning Technique for Optical Coherence Tomography". Journal of Optics 30, n.º 4 (diciembre de 2001): 151–57. http://dx.doi.org/10.1007/bf03354735.

Texto completo

Los estilos APA, Harvard, Vancouver, ISO, etc.

35

Nugent, K. A. y J. E. Trebes. "Coherence measurement technique for short‐wavelength light sources". Review of Scientific Instruments 63, n.º 4 (abril de 1992): 2146–51. http://dx.doi.org/10.1063/1.1143130.

Texto completo

Los estilos APA, Harvard, Vancouver, ISO, etc.

36

Kim, H. C., M. G. Cho, J. Kim, J. H. Park y J. Shim. "Coherence technique for noise reduction in rotary compressor". Journal of Mechanical Science and Technology 26, n.º 7 (julio de 2012): 2073–76. http://dx.doi.org/10.1007/s12206-012-0517-1.

Texto completo

Los estilos APA, Harvard, Vancouver, ISO, etc.

37

Cao, Haitao y Roohollah Askari. "Comparison of seismic interferometry techniques for the retrieval of seismic body waves in CO2 sequestration monitoring". Journal of Geophysics and Engineering 16, n.º 6 (7 de octubre de 2019): 1094–115. http://dx.doi.org/10.1093/jge/gxz079.

Texto completo

Resumen

Abstract Ambient noise seismic interferometry performed by cross-correlation has been proven to be a potential cost-effective technique for geological studies. To improve the resolution of images created by interferometry, additional techniques using deconvolution and cross-coherence have been introduced. While all three methods have previously been evaluated using surface wave data for shear-wave imaging of the near surface, comparatively little study has been devoted to assess the three methods for the retrieval of body waves in reflection surveys for time-lapse application. Moreover, although the application of seismic interferometry to CO2 sequestration by cross-correlation has been investigated by many researchers, to our knowledge, similar time-lapse studies have not been conducted using deconvolution and cross-coherence methods. We evaluate the three methods of cross-correlation, deconvolution and cross-coherence for the retrieval of phase information contained in virtual seismic records by applying seismic interferometry to synthetic data, using a model reservoir before and after CO2 injection. By examining two approaches of regularization and smoothing factors to suppress spurious reflection events observed on the deconvolution and cross-coherence results, we note that both approaches provide similar results. We investigate noise effects by adding random noise independently at each geophone. Finally, we apply these techniques to field data recorded near the CO2 storage site in Ketzin, Germany. For both our numerical and field data studies, we find that the cross-coherence technique retrieves the phase information of body-wave data more effectively than the cross-correlation and deconvolution techniques, and is less sensitive to uncorrelated noise from shallow sources.

Los estilos APA, Harvard, Vancouver, ISO, etc.

38

Tomić, Miloš C. y Zoran V. Đinović. "Position Measurement over Wide Range by Simultaneous Use of Low and High Coherence Light Source". Electronics ETF 19, n.º 2 (15 de julio de 2016): 74. http://dx.doi.org/10.7251/els1519074t.

Texto completo

Resumen

In this paper we propose and experimentally demonstrate a new technique for position/displacement measurement using fiber optic interferometry. We simultaneously employ a low- and a high- coherence light source in the same opto-mechanical configuration. The low coherence signal was obtained using a Fizeau receiving interferometer, implemented as an optical glass wedge, accompanied by a linear CCD array. Combining low- and high-coherence parts was possible because we showed that the accuracy of low-coherence based position measurement was better than 50 nm, less than the high coherence signal periodicity. We verify the method in the dynamic range of low-coherence measurement of about 100 m, while the accuracy of the high-coherence part was about ±1 nm. Thus, the method provides more than 100,000 measuring points. The advantages of this sensing technique include absolute position/displacement measurement in a large dynamic range with nanometer accuracy.

Los estilos APA, Harvard, Vancouver, ISO, etc.

39

Yoo, Kookhyun y Un-Chang Jeong. "Identification of Automotive Seat Rattle Noise Using an Independent Component Analysis-Based Coherence Analysis Technique". Applied Sciences 10, n.º 20 (10 de octubre de 2020): 7027. http://dx.doi.org/10.3390/app10207027.

Texto completo

Resumen

This study proposed a contribution evaluation through the independent component analysis (ICA) method. The necessity of applying ICA to the evaluation of contribution was investigated through numerical simulation. Moreover, the estimation of the number of input sources, the labeling of signals, and the restoration of the signal amplitude were considered to perform the ICA-based coherence evaluation. The contribution evaluation was performed using the coherence evaluation method and by applying the established ICA-based coherence evaluation method to the seat rattle noise of the vehicle. According to the result of the evaluation, with the coherence evaluation technique it was difficult to calculate the contribution in identifying noise sources that overlap in both spatially and in frequency, because it was challenging to distinguish between the two measured signals. By contrast, the ICA-based coherence evaluation was able to restore the original source and investigate the contribution.

Los estilos APA, Harvard, Vancouver, ISO, etc.

40

Bock, Markus, Alexander Ulrich Brandt, Jan Dörr, Caspar F. Pfueller, Stephanie Ohlraun, Frauke Zipp y Friedemann Paul. "Time domain and spectral domain optical coherence tomography in multiple sclerosis: a comparative cross-sectional study". Multiple Sclerosis Journal 16, n.º 7 (29 de marzo de 2010): 893–96. http://dx.doi.org/10.1177/1352458510365156.

Texto completo

Resumen

Conventional time domain optical coherence tomography has been established for the in vivo assessment of retinal axonal loss in multiple sclerosis. The innovative spectral domain imaging is superior to the conventional technique with respect to data acquisition speed, resolution and reproducibility. However, until now comparability of the two techniques has not been investigated in multiple sclerosis. In this study involving 55 multiple sclerosis patients, data obtained using both techniques (Stratus time domain optical coherence tomography and Cirrus spectral domain optical coherence tomography, Carl Zeiss Meditec) showed an excellent correlation (Pearson’s r = 0.926, p < 0.001). However, owing to considerable differences in absolute retinal nerve fibre layer measurements (mean ± standard deviation 8.1 µm ± 6.2, range -12 to 23 µm), results from the two devices are not interchangeable.

Los estilos APA, Harvard, Vancouver, ISO, etc.

41

Wati, Ismi Isma, Sri Mulyati Mulyati y Khusnul Khotimah Khotimah. "KOHESI DAN KOHERENSI DALAM NOVEL KKN DI DESA PENARI KARYA SIMPLEMAN DAN IMPLIKASINYA TERHADAP PEMBELAJARAN BAHASA INDONESIA DI SMA". Jubindo: Jurnal Ilmu Pendidikan Bahasa dan Sastra Indonesia 5, n.º 3 (26 de enero de 2021): 123–31. http://dx.doi.org/10.32938/jbi.v5i3.612.

Texto completo

Resumen

Cohesion and coherence have an important role in writing essays, both those that will write or those that have become essays. Therefore this study aims to determine the use of cohesion and coherence in the KKN novel in Penari Village. The object of this research is the KKN novel in Penari Village by Simpleman. The subject of this research is the sentence which contains the type of cohesion and coherence in the KKN novel in Penari Village by Simpleman. The approach used is a qualitative approach. A qualitative approach is an approach that presents data in the form of sentences. The design of this research is by collecting data, then the data is grouped according to the use of cohesion and coherence types, then the data is analyzed and presented in an informal form. Data collection techniques using reading techniques and note taking techniques. The technique of presenting the results of the analysis using informal techniques. Informal techniques are techniques that present data in the form of common words that are easily understood by the reader. The results of this study are grammatical cohesion, lexical cohesion and coherence types. Grammatical cohesion includes: reference, substitution, ellipsis, and conjunction. The use of lexical cohesion are of two types namely, repetition and collocation. The use of coherence there are five relationships, namely: the sum relationship, the sequential relationship, the resistance relationship, the causal relationship, and the time relationship.

Los estilos APA, Harvard, Vancouver, ISO, etc.

42

Garcia-Escartin, J. C. y P. Chamorro-Posada. "Quantum multiplexing with optical coherent states". Quantum Information and Computation 9, n.º 7&8 (julio de 2009): 573–93. http://dx.doi.org/10.26421/qic9.7-8-2.

Texto completo

Resumen

In this paper, we propose a novel quantum multiple access technique based on optical coherent states. The information of several coherent state optical qubits is combined into a single qudit, which is the superposition of almost orthogonal coherent states. The original information is encoded into a new Hilbert space with the help of a quantum multiplexer (QMUX) and then recovered at the other end with a quantum demultiplexer (QDEMUX). We introduce the optical tools that complete the coherence state quantum computation model and give the desired circuits. The proposed system can admit a number of users above the optimal limit at the cost of a degradation of the transmitted data. In this and some other aspects, it can be regarded as a quantum analogue of classical Code Division Multiple Access techniques.

Los estilos APA, Harvard, Vancouver, ISO, etc.

43

Shreedhar Bhat, Gautam, Nikhil Shankar y Issa Panahi. "Real-time joint dereverberation and speech enhancement for hearing aid applications using edge devices". Journal of the Acoustical Society of America 150, n.º 4 (octubre de 2021): A348. http://dx.doi.org/10.1121/10.0008541.

Texto completo

Resumen

In this work, we propose a joint dereverberation and speech enhancement technique for real-time applications. Speech dereverberation is based on the coherent-to-diffuse energy ratio (CDR) measured from the direction-of-arrival (DOA) dependent complex spatial coherence function. A personalized speech enhancement (SE) technique based on joint maximum a posteriori probability (JMAP) estimation that inherently accounts for the effects of changes in acoustic path and reverberation is used. The combination of these masking functions is used to enhance the speech corrupted by reverberation and noise in a frame-by-frame process. The proposed method is implemented on the smartphone (edge device), to illustrate real-time usability. The efficiency of the proposed method is evaluated using speech quality and intelligibility measures and compared with that of other benchmark techniques.

Los estilos APA, Harvard, Vancouver, ISO, etc.

44

Chopra, Satinder y Kurt J. Marfurt. "Coherence attribute applications on seismic data in various guises — Part 2". Interpretation 6, n.º 3 (1 de agosto de 2018): T531—T541. http://dx.doi.org/10.1190/int-2018-0007.1.

Texto completo

Resumen

We have previously discussed some alternative means of modifying the frequency spectrum of the input seismic data to modify the resulting coherence image. The simplest method was to increase the high-frequency content by computing the first and second derivatives of the original seismic amplitudes. We also evaluated more sophisticated techniques, including the application of structure-oriented filtering to different spectral components before spectral balancing, thin-bed reflectivity inversion, bandwidth extension, and the amplitude volume technique. We further examine the value of coherence computed from individual spectral voice components, and alternative means of combining three or more such coherence images, providing a single volume for interpretation.

Los estilos APA, Harvard, Vancouver, ISO, etc.

45

Ushakov, N. A., T. A. Makovetskaya, A. A. Markvart y L. B. Liokumovich. "Theoretical Foundations of Quantum Spectral-Domain Optical Coherence Tomography with Frequency Scanning". JETP Letters 117, n.º 1 (enero de 2023): 24–31. http://dx.doi.org/10.1134/s0021364022602871.

Texto completo

Resumen

A quantum spectral-domain optical coherence tomography technique based on the control of the joint spectral amplitude of a biphoton has been developed. An analytical expression for a quantum spectral-domain optical coherence tomography signal has been obtained in the case of a Gaussian joint spectral amplitude. The effect of the shape of the joint spectral amplitude of the biphoton on the resulting interference signal has been analyzed. The possibility of improving the quality of the interference signal by controlling the parameters of the joint spectral amplitude has been considered. It has been shown theoretically that the proposed approach provides a higher longitudinal spatial resolution than other optical coherence tomography techniques.

Los estilos APA, Harvard, Vancouver, ISO, etc.

46

Wang, Xiaofan, Chao Feng, Tao Liu, Zhen Zhang, Cheng-Ying Tsai, Juhao Wu, Chuan Yang y Zhentang Zhao. "Angular dispersion enhanced prebunch for seeding ultrashort and coherent EUV and soft X-ray free-electron laser in storage rings". Journal of Synchrotron Radiation 26, n.º 3 (12 de abril de 2019): 677–84. http://dx.doi.org/10.1107/s1600577519002674.

Texto completo

Resumen

Prebunching is an effective technique to reduce the radiation saturation length and to improve the longitudinal coherence and output stability in storage-ring-based free-electron lasers (FELs). A novel technique is proposed which uses angular dispersion to enhance the high-harmonic bunching with very small laser-induced energy spread. This technique can effectively reduce the radiation saturation length without significantly reducing the peak power of the FEL. Numerical simulations demonstrate that this technique can be used for the generation of 100 MW scale level, fully temporal coherent femtosecond extreme-ultraviolet and soft X-ray radiation pulses through a 10 m-long undulator based on a diffraction-limited storage ring.

Los estilos APA, Harvard, Vancouver, ISO, etc.

47

Alexandrov, Sergey A., Hrebesh M. Subhash, Azhar Zam y Martin Leahy. "Nano-sensitive optical coherence tomography". Nanoscale 6, n.º 7 (2014): 3545–49. http://dx.doi.org/10.1039/c3nr06132a.

Texto completo

Los estilos APA, Harvard, Vancouver, ISO, etc.

48

Lockwood, Michael D. "Proprioceptive Coherence: An Expanded View of the Mechanics Behind the Indirect Method and the Introduction of an Innovative Variation". AAO Journal 31, n.º 1 (1 de marzo de 2021): 15–31. http://dx.doi.org/10.53702/2375-5717-31.1.15.

Texto completo

Resumen

Abstract Proprioceptive coherence is proposed as a novel osteopathic treatment technique whereby the desired technique response is rapid, resulting from the sensory integration of multiple diverse proprioceptive, somatosensory, nociceptive, neuroendocrine elements contributing to focal somatic dysfunction. Volitional components involving the cerebral cortex, emotional contributions from the limbic system as well as prioritization of the motor responses to dysfunction contribute to mechanisms putatively involved with the technique. The technique has a unique obligatory focus on a temporal element. To better comprehend this treatment approach, diverse determinants of somatic dysfunction such as altered proprioceptive input, muscular influences, nociception, spinal cord processing and higher level central processing are discussed including muscular, aspects of mechanical transduction and tensegrity, nociception, spinal cord, and central processing. The diagnostic component of this technique involves identification of primarily interoceptive, proprioceptive and somatosensory related tissue alterations and considers a secondary exteroceptive contribution. The treatment phase is dictated by perception of precise balancing of localized forces on the area of dysfunction. A mandatory physician participation is dictated by the feed forward unique chronoception component. At the completion of the technique, rapid therapeutic effects are perceived by both the physician and the patient. This paper is intended to appeal to the scientist in all of us; the lover of osteopathic manipulative techniques, and the healer we embrace as practicing osteopathic physicians. To help establish proprioceptive coherence as a novel technique, a comparison to common forms of osteopathic treatment based upon the indirect method is presented. It is proposed that proprioceptive coherence is a novel technique with unique mechanisms however others may consider the technique as a refinement of existing indirect methods.

Los estilos APA, Harvard, Vancouver, ISO, etc.

49

Aditiawarman, Mac y Riski Rahmadanil Putra. "Semiotic Analysis of Carving Symbol on Minangkabau Traditional House Rajo Mulie in South Solok". Jurnal Ilmiah Langue and Parole 8, n.º 1 (2 de diciembre de 2024): 9–16. https://doi.org/10.36057/jilp.v8i1.684.

Texto completo

Resumen

This research aims to describe the relationship between the form of cohesion and the meaning of coherence in the discourse analysis of Sandiaga Uno's Speech in the High Level Thematic Debate On Tourism United Nation General Assembly 2022. The frequency of use of cohesion markers and coherence varies in their use, in The subject of this study focused on sentences in speech texts. The theoretical research used in this research is Tarigan's theory which discusses aspects of cohesion and coherence. This research is the researcher himself with based on knowledge of theories regarding aspects of cohesion and coherence. This study used qualitative descriptive method Data were collected through observation methods. Then, the data is analyzed through the method of interpretive findings with the technique of collecting data taking notes techniques. The results showed that markers of cohesion and coherence were used in the script of Sandiaga Uno's speech. Shows the element of grammatical cohesion consists of elements of reference, subtitution, ellipsis, and conjuction. Then The lexical cohesion element consists of repetition, synonymy, antonymy, collocation. From the aspect of coherence observed through contradiction, contrast, and temporal coherence.

Los estilos APA, Harvard, Vancouver, ISO, etc.

50

Moxham, Thomas E. J., Aaron Parsons, Tunhe Zhou, Lucia Alianelli, Hongchang Wang, David Laundy, Vishal Dhamgaye, Oliver J. L. Fox, Kawal Sawhney y Alexander M. Korsunsky. "Hard X-ray ptychography for optics characterization using a partially coherent synchrotron source". Journal of Synchrotron Radiation 27, n.º 6 (16 de octubre de 2020): 1688–95. http://dx.doi.org/10.1107/s1600577520012151.

Texto completo

Resumen

Ptychography is a scanning coherent diffraction imaging technique which provides high resolution imaging and complete spatial information of the complex electric field probe and sample transmission function. Its ability to accurately determine the illumination probe has led to its use at modern synchrotrons and free-electron lasers as a wavefront-sensing technique for optics alignment, monitoring and correction. Recent developments in the ptychography reconstruction process now incorporate a modal decomposition of the illuminating probe and relax the restriction of using sources with high spatial coherence. In this article a practical implementation of hard X-ray ptychography from a partially coherent X-ray source with a large number of modes is demonstrated experimentally. A strongly diffracting Siemens star test sample is imaged using the focused beam produced by either a Fresnel zone plate or beryllium compound refractive lens. The recovered probe from each optic is back propagated in order to plot the beam caustic and determine the precise focal size and position. The power distribution of the reconstructed probe modes also allows the quantification of the beams coherence and is compared with the values predicted by a Gaussian–Schell model and the optics exit intensity.

Los estilos APA, Harvard, Vancouver, ISO, etc.

Artículos de revistas sobre el tema "Coherence technique"

Crea una cita precisa en los estilos APA, MLA, Chicago, Harvard y otros