Zeitschriftenartikel: „Fresnel transformation“

1

Xie, Chuan-Mei, und Hong-Yi Fan. „The Fresnel—Weyl complementary transformation“. Chinese Physics B 21, Nr. 10 (Oktober 2012): 100302. http://dx.doi.org/10.1088/1674-1056/21/10/100302.

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2

Fan, Hong-Yi, und Li-yun Hu. „Optical Fresnel transformation and quantum tomography“. Optics Communications 282, Nr. 18 (September 2009): 3734–36. http://dx.doi.org/10.1016/j.optcom.2009.06.031.

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3

Xie, Chuan-Mei, und Hong-Yi Fan. „Fresnel–Hadamard complementary transformation in quantum optics“. Journal of Modern Optics 57, Nr. 7 (10.04.2010): 582–86. http://dx.doi.org/10.1080/09500341003789934.

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4

Krasnopevtsev, E. A. „The Fourier-Fresnel transformation in holographic interferometry“. Journal of Optical Technology 73, Nr. 2 (01.02.2006): 96. http://dx.doi.org/10.1364/jot.73.000096.

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5

WANG, SHUAI, HONG-CHUN YUAN und HONG-YI FAN. „FRESNEL OPERATOR, SQUEEZED STATE AND WIGNER FUNCTION FOR CALDIROLA–KANAI HAMILTONIAN“. Modern Physics Letters A 26, Nr. 19 (21.06.2011): 1433–42. http://dx.doi.org/10.1142/s0217732311035778.

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Based on the technique of integration within an ordered product (IWOP) of operators, we introduce the Fresnel operator for converting a kind of time-dependent Hamiltonian into the standard harmonic oscillator Hamiltonian. The Fresnel operator with the parameters A, B, C, D corresponds to classical optical Fresnel transformation, these parameters are the solution to a set of coupled partial differential equations set up in the above-mentioned converting process. In this way, the Caldirola–Kanai Hamiltonian has been easily converted into the standard harmonic oscillator Hamiltonian. And then the exact wave function solution of the Schrödinger equation governed by the Caldirola–Kanai Hamiltonian is obtained, which represents a squeezed number state. The corresponding Wigner function is derived by virtue of the Weyl ordered form of the Wigner operator and the order-invariance of Weyl ordered operators under similar transformations.

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Wang, Huai Sheng. „A No Interference Optical Image Encryption by a Fresnel Diffraction and a Fourier Transformation“. Advanced Materials Research 459 (Januar 2012): 461–64. http://dx.doi.org/10.4028/www.scientific.net/amr.459.461.

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A no interference optical image encryption is put forward in this paper. The encrypting process is composed of a Fresnel diffraction and a Fourier transformation. A digital image coded with a random phase plate first takes a Fresnel diffraction. The diffraction function is enlarged and coded with another random phase mask. At last the enlarged function undergoes a Fourier transformation. The real part of the transformed function is defined as an encrypted image. In decrypting process, first the encrypted image takes an inverse Fourier transformation. Then the upper left corner of the transformed function is intercepted. According to the space inversion of the transformed function, if the intercepted function takes an inverse Fresnel diffraction, the original digital image can be restored from the final diffraction function. Because there is no interference process in encryption and decryption, the optical system is relatively simple and the quality of restored image is very good

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Yang, Rui, Zhaoxu Wang, He Su, Yinan Yang und Zhenya Lei. „Bi-functional Fresnel zone plate from transformation optics“. Journal of Optics 17, Nr. 7 (10.06.2015): 075602. http://dx.doi.org/10.1088/2040-8978/17/7/075602.

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8

Xie, Chuan-mei, und Hong-yi Fan. „The generalized Fresnel–Hadamard complementary transformation for asymmetric beamsplitter“. Optik 123, Nr. 9 (Mai 2012): 784–87. http://dx.doi.org/10.1016/j.ijleo.2011.04.025.

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9

Xie, Chuan-mei, und Tong-tong Wang. „The Fresnel–fractional Hadamard combinatorial transformation for symmetric beamsplitter“. Optik 124, Nr. 6 (März 2013): 477–82. http://dx.doi.org/10.1016/j.ijleo.2012.02.004.

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10

Wang, Huai Sheng. „The Temporal Diffraction Characteristic of a Femtosecond Laser Pulse by a Serrated Aperture“. Applied Mechanics and Materials 268-270 (Dezember 2012): 1353–56. http://dx.doi.org/10.4028/www.scientific.net/amm.268-270.1353.

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Based on Fresnel diffraction theory we give out the light field distribution for the definite frequency component of a femtosecond laser pulse when the laser pulse passes through a serrated aperture. Through an inverse Fourier transformation, we get the temporal diffraction field function of the femtosecond laser pulse at any distance. The temporal diffraction field function is related to the width of the laser pulse, the structure of the serrated aperture, the Fresnel number at central frequency and time. Number calculation shows when the width of the laser pulse is within a few tens of femtoseconds and Fresnel number at central frequency is much, the temporal diffraction intensity is not a Gaussian distribution. Nevertheless when Fresnel number at central frequency is less than ten, the temporal diffraction intensity can be approximately regarded as a Gaussian distribution and has a time delay effect.

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Sun, Jianguo. „3-D crosswell transmissions: Paraxial ray solutions and reciprocity paradox“. GEOPHYSICS 60, Nr. 3 (Mai 1995): 810–20. http://dx.doi.org/10.1190/1.1443819.

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Transmission of seismic waves through a 3-D earth model is of fundamental importance in seismology. If the model consists of many layers separated by curved interfaces, the only feasible solution to the transmitted waves is the one given by the geometrical optics approximation. Transmitted rays, transmitted wavefield, and the first Fresnel zone associated with a transmission point can be expressed by four 2 × 2 constant matrices constituting the 4 × 4 linearized ray transformation matrix. Generally, the ray transformation matrix can be constructed by dynamic ray tracing. However, if the layers are homogeneous, it can be formulated in closed form by using elementary vector calculus and coordinate transformations. Using the symplecticity of the ray transformation matrix, transmissions in opposite directions can be formulated by the ray transformation matrix for only one direction, and a reciprocity relation can be established. After the decomposition theorem for the ray transformation matrix, the transmitted wavefield in a model with many curved interfaces can be computed in a cascaded way. Using the [Formula: see text]‐matrix decomposition theorem, the normalized geometrical spreading factor can be expressed by means of the area of the first Fresnel zone of a transmission point. If seismic waves propagate through a locally spherical interface, the reciprocity relation may not hold. Using ray theory, this fact is shown by formulating the transmitted wavefield with the two principal radii of curvature of the transmitted wavefront at the transmission point under consideration. Using wave theory, this fact is shown by analyzing the Debye integral with the method of stationary phase.

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Oh, Soon-Soo, Woo-Su Kim und Young-Hwan Lee. „EIRP Characterization of Electrically Large Wireless Equipment with Integrated Signal Generator in a Compact Environment“. International Journal of Antennas and Propagation 2015 (2015): 1–5. http://dx.doi.org/10.1155/2015/383925.

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We describe a measurement technique to characterize the equivalent isotropically radiated power (EIRP) of electrically large wireless equipment in a compact environment. A modified phase-measurement method was proposed and, thus, the separation of the signal generator and radiating element was not required during the measurement. A Fresnel-to-far-field transformation was used for the fast measurement time in a compact anechoic chamber. An experimental verification of the method was carried out in a compact anechoic chamber, where the source-detector separation was approximately 1/5 of the far-field distance. The measured magnitude and phase pattern exhibited only a small error. The EIRP obtained using a Fresnel-to-far-field transformation was compared with a reference value, and the error was within 0.5 dB.

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FAN, HONG-YI, und HAI-LIANG LU. „CLASSICAL OPTICAL TRANSFORMS STUDIED IN THE CONTEXT OF QUANTUM OPTICS VIA THE ROUTE OF DEVELOPING DIRAC'S SYMBOLIC METHOD“. International Journal of Modern Physics B 19, Nr. 05 (20.02.2005): 799–856. http://dx.doi.org/10.1142/s0217979205029389.

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Via the route of developing Dirac's symbolic method and following Dirac's assertion: "⋯ for a quantum dynamic system that has a classical analogue, unitary transformation in the quantum theory is the analogue of contact transformation in the classical theory", we find the generalized Fresnel operator (GFO) corresponding to the generalized Fresnel transform (GFT) in classical optics. We derive GFO's normal product form and its canonical coherent state representation and find that GFO is the loyal representation of symplectic group multiplication rule. We show that GFT is just the transformation matrix element of GFO in the coordinate representation such that two successive GFTs is still a GFT. The ABCD rule of the Gaussian beam propagation is directly demonstrated in quantum optics. With the aid of entangled state representation the entangled Fresnel transform is proposed; new eigenfunctions of the complex fractional Fourier transform and fractional Hankel transform are obtained; the two-variable Hermite eigenmodes of light propagation are used in studying the Talbot effect in quadratic-index media; the complex wavelet transform and the condition of mother wavelet are studied in the context of quantum optics too. Moreover, quantum optical version of classical z-transforms is obtained on the basis of the eigenvector of creation operator. Throughout our discussions, the coherent state, squeezing operators and the technique of integration within an ordered product (IWOP) of operators are fully used.

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Ivanka, Ján, und Hana Chudá. „Theory of Near–Zone Measurement with Transformation to Aerial Surface and Gain Measurement“. Journal of Electrical Engineering 66, Nr. 2 (01.03.2015): 85–90. http://dx.doi.org/10.1515/jee-2015-0013.

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Abstract The paper presents an analysis study of the theory of measurement in the near, Fresnel and Fraunhofer zone with transformation to aerial surface as well as real measurements of the gain of aerial system of electromagnetic fields of devices and components used in the safety industry in an aneochoic chamber.

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Moon, Inkyu, und Bahram Javidi. „Three-dimensional identification of stem cells by computational holographic imaging“. Journal of The Royal Society Interface 4, Nr. 13 (21.11.2006): 305–13. http://dx.doi.org/10.1098/rsif.2006.0175.

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We present an optical imaging system and mathematical algorithms for three-dimensional sensing and identification of stem cells. Data acquisition of stem cells is based on holographic microscopy in the Fresnel domain by illuminating the cells with a laser. In this technique, the holograms of stem cells are optically recorded with an image sensor array interfaced with a computer and three-dimensional images of the stem cells are reconstructed from the Gabor-filtered digital holograms. The Gabor wavelet transformation for feature extraction of the digital hologram is performed to improve the process of identification. The inverse Fresnel transformation of the Gabor-filtered digital hologram is performed to reconstruct the multi-scale three-dimensional images of the stem cells at different depths along the longitudinal direction. For recognition and classification of stem cells, a statistical approach using an empirical cumulative density function is introduced. The experiments indicate that the proposed system can be potentially useful for recognizing and classifying stem cells. To the best of our knowledge, this is the first report on using three-dimensional holographic microscopy for automated identification of stem cells.

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Волосюк, Валерий Константинович, Семён Сергеевич Жила, Глеб Сергеевич Черепнин und Эдуард Алексеевич Цернэ. „ВОССТАНОВЛЕНИЕ КОГЕРЕНТНЫХ ИЗОБРАЖЕНИЙ ПОВЕРХНОСТЕЙ В ЗОНЕ ФРЕНЕЛЯ МЕТОДАМИ МНОГОКАНАЛЬНОЙ ОБРАБОТКИ СИГНАЛОВ“. RADIOELECTRONIC AND COMPUTER SYSTEMS, Nr. 3 (30.10.2018): 97–102. http://dx.doi.org/10.32620/reks.2018.3.10.

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The generalized structure of the electromagnetic field in the registration area is considered in the case of the solution of problems of remote sensing of the underlying surfaces. Examples of the existing radar and optical coherent devices are given. Analytical expressions for the electromagnetic field in the reception area when sounding is carried out in a near-field Fresnel region, in the assumption that the size of the field of registration and radiation is considerably less than a distance between them, are concretized. It is shown the main operations that are necessary for the recovery of coherent images in a near-field Fresnel region by the methods of multichannel signal processing. Research shows that as the amplitude-phase distribution of the registration field is necessary to choose the classical basic function of Fresnel transformation with the reversed sign in the exponent power. Formally, in an infinite range, the Fresnel transform is invertible, i.e. in the ideal case, the function can be completely restored. However physically to Fresnel's region satisfies area with finite sizes. From the analysis of the obtained operations over the received field, it follows that the radar or optical system forms an estimate of the coherent image in the form of a convolution of a true image of the underlying surface with an ambiguity function. Generally, this function contains two multipliers, one of which determines the resolution of recovery of the coherent image. In that specific case, when the linear sizes of the field of registration go to infinity, ambiguity function takes a form of delta function and the required image can be restored without distortions. It is offered to determine resolution by the width between first zeros of ambiguity function. For rectangular area ambiguity function has the form of two sinc functions which width is directly proportional to wavelength, to the height of sounding and is inversely proportional to the linear sizes of receiving area on the corresponding coordinates. Finally, it is mentioned that for the higher-quality coherent imaging with good resolution by the same receiving area it is necessary to perform scanning and movement in space

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Ganci, S. „Diffracted wavefield by an arbitrary aperture from Maggi–Rubinowicz transformation: Fresnel approximation“. Optik 122, Nr. 3 (Februar 2011): 241–46. http://dx.doi.org/10.1016/j.ijleo.2009.09.017.

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18

Wang, Huai Sheng. „Research on Applied Technology with the Characteristic of the Spatial Fresnel Diffraction Field of a Circle Aperture Illuminated by a Hyperbolic Secant Optical Pulse“. Advanced Materials Research 859 (Dezember 2013): 473–76. http://dx.doi.org/10.4028/www.scientific.net/amr.859.473.

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Based on the Fresnel diffraction theory and the principle of Fourier transformation, an equation is put forward to analyze the spatial diffraction intensity distribution of a circle aperture illuminated by a hyperbolic secant optical femtosecond pulse. The spatial diffraction intensity distributions are determined by the distance, the radius of the circle aperture, the Fresnel number, the width and the central wavelength of the hyperbolic optical pulse. Number calculation shows that when the radius of the circle aperture is definite, the spatial diffraction intensity is a function of the distance z. If the distance is definite, the spatial diffraction intensity is a function of the radius of the circle aperture. In a definite extent the spatial diffraction intensity remains approximately a constant. A constant spatial intensity distribution is good for optical imaging and laser fusion.

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Fan, Hong-Yi, und Li-Yun Hu. „Relation between optical Fresnel transformation and quantum tomography in two-mode entangled case“. Journal of Modern Optics 58, Nr. 1 (10.01.2011): 45–51. http://dx.doi.org/10.1080/09500340.2010.543293.

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Du, Jian-Ming, und Hong-Yi Fan. „New decomposition of the Fresnel operator corresponding to the optical transformation inABCD-systems“. Chinese Physics B 22, Nr. 6 (Juni 2013): 060302. http://dx.doi.org/10.1088/1674-1056/22/6/060302.

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Yu, Yan Xin, Chun Yang Wang, Yu Chen und Hong Yan Sun. „A Fast Algorithm of Linear Canonical Transformation for Radar Signal Processing System“. Advanced Materials Research 1049-1050 (Oktober 2014): 1245–48. http://dx.doi.org/10.4028/www.scientific.net/amr.1049-1050.1245.

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Linear canonical transformation is a new signal processing tools developing in recent years. As a unified multi-parameter linear integral transform, linear canonical transformation has its unique advantages when dealing with non-stationary signal. However, from the existing literatures, the basic theoretical system is not perfect, some of the theories associated with signal processing needs to be further established or strengthened, the research of linear canonical transformation has important theoretical significance and practical significance, but linear canonical transformation needs a lot of calculation, it is not like Fourier transform, fractional Fourier transform, Fresnel transform and scale operator, they have already been widely used in various fields of expertise, in order to reduce the amount of calculation, this paper puts forward a fast algorithm which uses duality theorem of linear canonical transformation to reduce the amount of calculation, it can quickly complete the operation when we use linear canonical transformation to process the signal during radar signal processing, the time for normal algorithm is 5s, the fast algorithm needs only 0.2s.

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Wang, Huai Sheng. „A No Interference Optical Image Encryption by a Fresnel Diffraction and a Fourier Transformation“. Advanced Materials Research 459 (Januar 2012): 461–64. http://dx.doi.org/10.4028/scientific5/amr.459.461.

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23

Xu, Xing-Lei, Shi-Min Xu, Hong-Qi Li und Ji-Suo Wang. „A Generalized Hadamard-Fresnel Complementary Transformation Derived by Virtue of New Coherent-Entangled State“. International Journal of Theoretical Physics 50, Nr. 2 (27.10.2010): 385–94. http://dx.doi.org/10.1007/s10773-010-0540-x.

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SOLOOKINEJAD, GH, A. S. H. ROZATIAN und M. H. HABIBI. „INVESTIGATION OF SOL-GEL GROWN ZnO THIN FILM: WAVELET ANALYSIS AND SIMULATED ANNEALING OPTIMIZED X-RAY REFLECTIVITY“. International Journal of Modern Physics B 26, Nr. 10 (20.04.2012): 1250070. http://dx.doi.org/10.1142/s0217979212500701.

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In this study ZnO thin film was fabricated by sol-gel spin coating method on glass substrate. X-ray reflectivity (XRR) and its optimization by simulated annealing (SA) technique have been used for characterization and extracting physical parameters of the film. The model independent information was needed to establish data analyzing process for XRR before optimization process. This independent information was extracted from wavelet transform of Fresnel reflectivity normalized XRR. This transformation yields thickness of each coated layer. This information was a keynote for constructing optimization process. Specular XRR optimization yielded structural parameters such as thickness, roughness of surface and interface and electron density profile of the film. Acceptable agreement exists between results obtained from wavelet transformation and XRR fitting.

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Mousavizadeh, Farhood, Keivan Maghooli, Emad Fatemizadeh und Mohammad Shahram Moin. „Liveness Detection in Face Identification Systems: Using Zernike Moments and Fresnel Transformation of Facial Images“. Indian Journal of Science and Technology 8, Nr. 8 (05.04.2015): 523. http://dx.doi.org/10.17485/ijst/2015/v8i8/55787.

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ITO, Satoshi, Hirotoshi ARAI und Yoshifumi YAMADA. „Compressed Sensing in Magnetic Resonance Imaging Using the Multi-step Fresnel Domain Band Split Transformation“. Magnetic Resonance in Medical Sciences 11, Nr. 4 (2012): 243–52. http://dx.doi.org/10.2463/mrms.11.243.

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Soon-Soo Oh und Jae-Hoon Yun. „New Method for Predicting the Electromagnetic Field at a Finite Distance Using Fresnel Field Transformation“. IEEE Antennas and Wireless Propagation Letters 7 (2008): 291–93. http://dx.doi.org/10.1109/lawp.2008.921373.

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Wang, Zhi-long, Shan-jun Ma, Fang Jia und Hong-yi Fan. „Quantum Fresnel Transformation Responsible for Squeezing Mechanism and Squeezed State of a Degenerate Parametric Amplifier“. International Journal of Theoretical Physics 54, Nr. 5 (30.10.2014): 1720–25. http://dx.doi.org/10.1007/s10773-014-2373-5.

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Hirose, Chiaki, Naotoshi Akamatsu und Kazunari Domen. „Formulas for the Analysis of the Surface SFG Spectrum and Transformation Coefficients of Cartesian SFG Tensor Components“. Applied Spectroscopy 46, Nr. 6 (Juni 1992): 1051–72. http://dx.doi.org/10.1366/0003702924124385.

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Comprehensive expressions have been presented to facilitate the analysis of the surface sum-frequency generation (SFG) spectrum. The electric field components of the SFG beam for a given experimental setup have been related via appropriately defined Fresnel coefficients to the nonlinear source polarization, which in turn has been related to the electric fields of exciting visible and infrared beams through the macroscopic SFG susceptibility tensor. The coefficients of transformation have been given to relate the laboratory-fixed Cartesian components of the SFG tensor to the components described in a surface-fixed axis system. The tensor components have been further related to the components of the microscopic hyperpolarizability tensor of surface species, and the explicit expressions (in terms of the Euler angles defining molecular orientation) of the transformation coefficients are presented to describe the Cartesian tensor components described in a surface-fixed axis system by the molecule-fixed components.

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Goel, Navdeep, und Kulbir Singh. „A modified convolution and product theorem for the linear canonical transform derived by representation transformation in quantum mechanics“. International Journal of Applied Mathematics and Computer Science 23, Nr. 3 (01.09.2013): 685–95. http://dx.doi.org/10.2478/amcs-2013-0051.

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Abstract The Linear Canonical Transform (LCT) is a four parameter class of integral transform which plays an important role in many fields of signal processing. Well-known transforms such as the Fourier Transform (FT), the FRactional Fourier Transform (FRFT), and the FreSnel Transform (FST) can be seen as special cases of the linear canonical transform. Many properties of the LCT are currently known but the extension of FRFTs and FTs still needs more attention. This paper presents a modified convolution and product theorem in the LCT domain derived by a representation transformation in quantum mechanics, which seems a convenient and concise method. It is compared with the existing convolution theorem for the LCT and is found to be a better and befitting proposition. Further, an application of filtering is presented by using the derived results.

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Fan, Hong-Yi, und Li-Yun Hu. „ABCD rule involved in the product of general SU(1,1) squeezing operators and quantum states’ Fresnel transformation“. Optics Communications 281, Nr. 6 (März 2008): 1629–34. http://dx.doi.org/10.1016/j.optcom.2007.11.033.

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Bahar, Ezekiel. „Transformation of Rice’s small perturbation solution for rough surface scattering into the high frequency reciprocal physical and geometric optics solutions“. Canadian Journal of Physics 90, Nr. 6 (Juni 2012): 557–64. http://dx.doi.org/10.1139/p2012-053.

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A step by step transformation of the low frequency small height and slope perturbation solution into the high frequency reciprocal and dual, physical and geometrical optic solutions is presented. The familiar Kirchhoff approximations for the fields impressed by the incident plane wave upon the rough surfaces results in nonreciprocal solutions. It is shown that the surface element scattering coefficients based on the Kirchhoff approximations agree with the corresponding reciprocal physical optics solutions only at the stationary phase, specular points on the rough surfaces. While the Kirchhoff approximations and physical optics approximations are based on the characterization of the surface fields by Fresnel reflection coefficients, the corresponding surface element scatter coefficient derived for the small perturbation solution and the full wave solutions are based on the imposition of boundary conditions for the tangential components of the electric and magnetic fields. A flow graph schematically depicting the relationships between these solutions for the scattered fields is also presented.

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Hirano, Keiichi, Yoshiki Yamashita, Yumiko Takahashi und Hiroshi Sugiyama. „Development of variable-magnification X-ray Bragg optics“. Journal of Synchrotron Radiation 22, Nr. 4 (25.06.2015): 956–60. http://dx.doi.org/10.1107/s1600577515008802.

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A novel X-ray Bragg optics is proposed for variable-magnification of an X-ray beam. This X-ray Bragg optics is composed of two magnifiers in a crossed arrangement, and the magnification factor,M, is controlled through the azimuth angle of each magnifier. The basic properties of the X-ray optics such as the magnification factor, image transformation matrix and intrinsic acceptance angle are described based on the dynamical theory of X-ray diffraction. The feasibility of the variable-magnification X-ray Bragg optics was verified at the vertical-wiggler beamline BL-14B of the Photon Factory. For X-ray Bragg magnifiers, Si(220) crystals with an asymmetric angle of 14° were used. The magnification factor was calculated to be tunable between 0.1 and 10.0 at a wavelength of 0.112 nm. At various magnification factors (M≥ 1.0), X-ray images of a nylon mesh were observed with an air-cooled X-ray CCD camera. Image deformation caused by the optics could be corrected by using a 2 × 2 transformation matrix and bilinear interpolation method. Not only absorption-contrast but also edge-contrast due to Fresnel diffraction was observed in the magnified images.

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Zapata-Rodrı́guez, Carlos J., Pedro Andrés, Manuel Martı́nez-Corral und Laura Muñoz-Escrivá. „Gaussian imaging transformation for the paraxial Debye formulation of the focal region in a low-Fresnel-number optical system“. Journal of the Optical Society of America A 17, Nr. 7 (01.07.2000): 1185. http://dx.doi.org/10.1364/josaa.17.001185.

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Padilla, Isabel, Aurora López-Delgado, Sol López-Andrés, Marta Álvarez, Roberto Galindo und Alfonso J. Vazquez-Vaamonde. „The Application of Thermal Solar Energy to High Temperature Processes: Case Study of the Synthesis of Alumina from Boehmite“. Scientific World Journal 2014 (2014): 1–7. http://dx.doi.org/10.1155/2014/825745.

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The aim of this paper is to evaluate the feasibility of obtaining alumina from boehmite using a free, clean, and unlimited power source as the solar energy. Boehmite was obtained by hydrothermal treatment of a hazardous waste coming from aluminum slag milling. The waste is considered as a hazardous substance because of it releasing toxic gases (hydrogen, ammonia, methane, and hydrogen sulfide) in the presence of water. The as-obtained boehmite was transformed into alumina, in air atmosphere, using a solar energy concentrator (Fresnel lens). The solar installation provides a power density of 260 W·cm−2which allows reaching temperatures upper than 1000°C at few minutes of exposure. Tests were performed at different periods of time that ranged between 5 and 90 min. The percentage of transformation of boehmite into alumina was followed by the water content of samples after solar radiation exposure. Samples were characterized by X-ray diffraction, infrared spectroscopy, and thermogravimetry. Metastable aluminas started to appear at 5 min and the crystalline and stable phase corundum at 10 min of solar radiation exposure.

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Kozlov, A. I., und V. Yu Maslov. „THE INVERSE-SCATTERING PROBLEM SOLUTION AND SHAPE FROM THE REFLECTED ELECTROMAGNETIC WAVE FIELD STRUCTURE“. Civil Aviation High TECHNOLOGIES 21, Nr. 3 (03.07.2018): 160–68. http://dx.doi.org/10.26467/2079-0619-2018-21-3-160-168.

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The reflected field calculation from the object can be described with the set of point reflectors with the coordinates in electromagnetic wave plane of incidence corresponding to two-dimensional grid nodes with rather small-sized step. At the same time, the single scattering model which does not consider the re-reflection and point elements cross impact is used in the reflected field calculations. The rapid direct and inverse transformation algorithm is used. The numerical solution algorithms of the direct and inverse scattering problems on the object are offered. The method uses the ray representations scattering fields which are based on the Huygens-Fresnel principle. The graphic diagram of the reciprocal object positioning and the observation plane from the reflected electromagnetic field object is represented. The double reflecting Gaussian surface is graphically figured. The figures of the module and the complex amplitude electric field strength of the reflected wave from a double Gaussian surface argument are provided. To shape the surface of the unknown object the recovery shape algorithm is used, by means of reflected wave phase. This algorithm is based on finding the complex matrix elements in dependence on absolute phase, which is proportional to the appropriate point object distance.

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Ma, Jian Ling. „Design of Dual-Wavelength High Precision Achro-Matic Phase Retarder“. Advanced Materials Research 586 (November 2012): 409–14. http://dx.doi.org/10.4028/www.scientific.net/amr.586.409.

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In order to meet the demand of precise measurement and applications, based on the total-reflection phase transformation theory of the phase retardation, the principle of phase retardation with oblique incident angle is expounded. Spectral characterization of the phase retardation varing with refractive index is analyzed to high precision achromatic phase retarder to oblique incidence aided design. The result indicates that there is a maximum to dispersion curve of achromatic phase retarder with oblique incident in the center of the design refractive index department. The phase-delay drops on both sides to the center of the refractive index and can pass through a definite retardance value twice at two specified wavelength values. Accordingly, based on the detailed design of Fresnel rhomb, The new achromatic retarder with the specific incident angle and high precision is designed by choosing suitable meterial .It is shown at the achromatic property curve within the range of 500 nm to 1150 nm theoretically that the maximum deviation of the retardance from 90° is 0.006°, whereas at λR1R=532 nm and λR2R=1064 nm the retardance is approximately 90°±0.001°. and the corresponding calculation to the size of the devices indicates that the size of the devices for the same aperture will decrease for higher refractive index values.So optical materials with higher refractive indices are more convenient for this type of oblique incidence retarder .

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Monzón, Juan José, und Luis L. Sánchez-Soto. „Fresnel formulas as Lorentz transformations“. Journal of the Optical Society of America A 17, Nr. 8 (01.08.2000): 1475. http://dx.doi.org/10.1364/josaa.17.001475.

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39

Волосюк, Валерий Константинович, Семён Сергеевич Жила, Эдуард Алексеевич Цернэ und Александр Иванович Стороженко. „МАТЕМАТИЧЕСКОЕ ОПИСАНИЕ ПРОЦЕДУР ПОСТРОЕНИЯ КОГЕРЕНТНЫХ ИЗОБРАЖЕНИЙ ПРИРОДНЫХ СРЕД В ЗОНЕ ФРАУНГОФЕРА МНОГОКАНАЛЬНЫМИ РАДИОТЕХНИЧЕСКИМИ СИСТЕМАМИ“. Aerospace technic and technology, Nr. 4 (14.10.2018): 92–97. http://dx.doi.org/10.32620/aktt.2018.4.11.

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The structure of the electromagnetic field in the domain of its registration is considered in the case of the solution of problems of remote sensing of the underlying surfaces on the basis of the phenomenological approach. This approach is mainly based on the theory of ray optics and the Huygens-Fresnel principle. It allows to determine the radiated and scattered fields for complex types of surfaces. Analysis of the structure of the electromagnetic field shows that it can be regarded as a mathematical transformation over the true image of the surface. In this case, the basic procedures for the coherent imaging in the far-field Fraunhofer region by multichannel radio-engineering systems should be based on the inverse transformation. For incomplete restoration of the desired image, without the phase and attenuation due to propagation, the basic operation is the inverse Fourier transform on the angular coordinates. The quality of the imaging in the Fraunhofer zone is determined by the ambiguity function. In a simple case of a rectangular receiving domain, ambiguity function has the form of two sinc functions which width is proportional to wavelength, to height of sounding and the linear sizes of receiving domain. If the distance to each point of the surface is known, then it is possible to completely reconstruct the coherent image. In this case, it is necessary to apply sliding short-scale Fourier transform to the received electromagnetic field. Obtained results correspond to the classical theory of resonance scattering. While ambiguity function is constant in the infinite limits of integration for a specific fixed value of the direction, only one spectral component (spatial harmonic) can be extracted from the desired image. it Is possible to allocate an ever wider range of spatial frequencies with the narrowing of the ambiguity function. In the limit, when the ambiguity function is a delta function, the full spectrum of frequencies of the desired image can be extracted, i.e. this function can be completely restored. If it is not possible to create a system with narrow ambiguity function then the higher-quality coherent image can be obtained by the same receiving domain by scanning or movement in space

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Abe, Sumiyoshi, und John T. Sheridan. „Almost-Fourier and almost-Fresnel transformations“. Optics Communications 113, Nr. 4-6 (Januar 1995): 385–88. http://dx.doi.org/10.1016/0030-4018(94)00521-u.

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41

Rougeot, R., und C. Aime. „Theoretical performance of serrated external occulters for solar coronagraphy“. Astronomy & Astrophysics 612 (April 2018): A80. http://dx.doi.org/10.1051/0004-6361/201732512.

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Context. This study is made in the context of the future solar coronagraph ASPIICS of the ESA formation-flying mission Proba-3. Aims. In the context of solar coronagraphy, we provide a comparative study of the theoretical performance of serrated (or toothed) external occulters by varying the number and size of the teeth, which we compare to the sharp-edged and apodized disks. The tooth height is small (a few centimeters), to avoid hindering the observation of the solar corona near the limb. We first analyze the diffraction pattern produced by such occulters. In a second step, we compute the umbra profile by integration over the Sun. Methods. We explored a few methods to compute the diffraction pattern. Two of them were implemented. The first is based on 2D fast Fourier transformation (FFT) routines and a multiplication by the Fresnel filter of the form exp(−iπλzu2). Simple rules were derived and discussed to set the sampling conditions. The Maggi–Rubinowicz representation is then proposed as an alternative method, and is proven to be very efficient for this study. Results. Serrated occulters tend to create a two-level intensity pattern, the inner being the darker, which perfectly matches a previously reported geometrical prediction. The diffraction in this central region is lower by two to four orders of magnitude when compared to the sharp-edged disk. The achieved umbra level at the center ranges from 10−4 to below 10−7, depending on the geometry of the teeth. Conclusions. Our study shows that serrated occulters can achieve a high rejection and can almost reach the performance of the apodized disk when very many teeth are used. We prove that shaped occulters must be preferred to simple disks in solar and stellar coronagraphy.

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Koroliov, Anton, Genyu Chen, Kenneth M. Goodfellow, A. Nick Vamivakas, Zygmunt Staniszewski, Peter Sobolewski, Mirosława El Fray et al. „Terahertz Time-Domain Spectroscopy of Graphene Nanoflakes Embedded in Polymer Matrix“. Applied Sciences 9, Nr. 3 (23.01.2019): 391. http://dx.doi.org/10.3390/app9030391.

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The terahertz time-domain spectroscopy (THz-TDS) technique has been used to obtain transmission THz-radiation spectra of polymer nanocomposites containing a controlled amount of exfoliated graphene. Graphene nanocomposites (1 wt%) that were used in this work were based on poly(ethylene terephthalate-ethylene dilinoleate) (PET-DLA) matrix and were prepared via a kilo-scale (suitable for research and development, and prototyping) in-situ polymerization. This was followed by compression molding into 0.3-mm-thick and 0.9-mm-thick foils. Transmission electron microscopy (TEM) and Raman studies were used to confirm that the graphene nanoflakes dispersed in a polymer matrix consisted of a few-layer graphene. The THz-radiation transients were generated and detected using a low-temperature–grown GaAs photoconductive emitter and detector, both excited by 100-fs-wide, 800-nm-wavelength optical pulses, generated at a 76-MHz repetition rate by a Ti:Sapphire laser. Time-domain signals transmitted through the nitrogen, neat polymer reference, and 1-wt% graphene-polymer nanocomposite samples were recorded and subsequently converted into the spectral domain by means of a fast Fourier transformation. The spectral range of our spectrometer was up to 4 THz, and measurements were taken at room temperature in a dry nitrogen environment. We collected a family of spectra and, based on Fresnel equations, performed a numerical analysis, that allowed us to extract the THz-frequency-range refractive index and absorption coefficient and their dependences on the sample composition and graphene content. Using the Clausius-Mossotti relation, we also managed to estimate the graphene effective dielectric constant to be equal to ~7 ± 2. Finally, we extracted from our experimental data complex conductivity spectra of graphene nanocomposites and successfully fitted them to the Drude-Smith model, demonstrating that our graphene nanoflakes were isolated in their polymer matrix and exhibited highly localized electron backscattering with a femtosecond relaxation time. Our results shed new light on how the incorporation of exfoliated graphene nanoflakes modifies polymer electrical properties in the THz-frequency range. Importantly, they demonstrate that the complex conductivity analysis is a very efficient, macroscopic and non-destructive (contrary to TEM) tool for the characterization of the dispersion of a graphene nanofiller within a copolyester matrix.

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VanderLugt, A., C. S. Anderson und P. J. W. Melsa. „Time-delay detection of short pulses by Fresnel and Fourier transformations“. Applied Optics 32, Nr. 20 (10.07.1993): 3761. http://dx.doi.org/10.1364/ao.32.003761.

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Fan, Hong-Yi, und Hai-Liang Lu. „Wave-function transformations by general SU(1,1) single-mode squeezing and analogy to Fresnel transformations in wave optics“. Optics Communications 258, Nr. 1 (Februar 2006): 51–58. http://dx.doi.org/10.1016/j.optcom.2005.07.044.

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Fan, Hong-Yi, und Jun-Hua Chen. „On the core of the fractional Fourier transform and its role in composing complex fractional Fourier transformations and Fresnel transformations“. Frontiers of Physics 10, Nr. 1 (Februar 2015): 1–6. http://dx.doi.org/10.1007/s11467-014-0445-x.

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Sakata, Hironobu, und Yuji Sakamoto. „Fast computation method for a Fresnel hologram using three-dimensional affine transformations in real space“. Applied Optics 48, Nr. 34 (11.11.2009): H212. http://dx.doi.org/10.1364/ao.48.00h212.

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47

Thompson, Ian. „An improved uniform approximation for diffraction integrals“. Proceedings of the Royal Society A: Mathematical, Physical and Engineering Sciences 462, Nr. 2069 (17.01.2006): 1341–53. http://dx.doi.org/10.1098/rspa.2005.1623.

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A saddle point formula for integrals whose integrands possess a multi-valued exponent, and one or more poles is derived. The result includes a number of error (or Fresnel) functions, which is equal to the product of the number of poles and the number of sheets possessed by the exponent's Riemann surface. Such formulae have previously been suggested on the basis of known exact results and transformations, both of which are specific to a particular exponent. In general, the multi-valuedness can be taken into account by a straightforward modification to a standard procedure, which would ordinarily yield only a single error function for each pole. In the context of diffraction theory, this type of approximation remains valid in the vicinity of an optical boundary, even in some cases where a wavefield is incident in a direction almost or exactly parallel to a sharp obstacle (grazing incidence).

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Deeley, George M., Martin Reinhard und Stephen M. Stearns. „Transformation and Sorption of 1,2‐Dibromo‐3‐Chloropropane in Subsurface Samples Collected at Fresno, California“. Journal of Environmental Quality 20, Nr. 3 (Juli 1991): 547–56. http://dx.doi.org/10.2134/jeq1991.00472425002000030008x.

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Portela, Esther, Nicolas Kolodziejczyk, Christophe Maes und Virginie Thierry. „Interior Water-Mass Variability in the Southern Hemisphere Oceans during the Last Decade“. Journal of Physical Oceanography 50, Nr. 2 (Februar 2020): 361–81. http://dx.doi.org/10.1175/jpo-d-19-0128.1.

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AbstractUsing an Argo dataset and the ECCOv4 reanalysis, a volume budget was performed to address the main mechanisms driving the volume change of the interior water masses in the Southern Hemisphere oceans between 2006 and 2015. The subduction rates and the isopycnal and diapycnal water-mass transformation were estimated in a density–spiciness (σ–τ) framework. Spiciness, defined as thermohaline variations along isopycnals, was added to the potential density coordinates to discriminate between water masses spreading on isopycnal layers. The main positive volume trends were found to be associated with the Subantarctic Mode Waters (SAMW) in the South Pacific and South Indian Ocean basins, revealing a lightening of the upper waters in the Southern Hemisphere. The SAMW exhibits a two-layer density structure in which subduction and diapycnal transformation from the lower to the upper layers accounted for most of the upper-layer volume gain and lower-layer volume loss, respectively. The Antarctic Intermediate Waters, defined here between the 27.2 and 27.5 kg m−3 isopycnals, showed the strongest negative volume trends. This volume loss can be explained by their negative isopyncal transformation southward of the Antarctic Circumpolar Current into the fresher and colder Antarctic Winter Waters (AAWW) and northward into spicier tropical/subtropical Intermediate Waters. The AAWW is destroyed by obduction back into the mixed layer so that its net volume change remains nearly zero. The proposed mechanisms to explain the transformation within the Intermediate Waters are discussed in the context of Southern Ocean dynamics. The σ–τ decomposition provided new insight on the spatial and temporal water-mass variability and driving mechanisms over the last decade.

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Waas, Florian, Robert Wrembel, Tobias Freudenreich, Maik Thiele, Christian Koncilia und Pedro Furtado. „On-Demand ELT Architecture for Right-Time BI“. International Journal of Data Warehousing and Mining 9, Nr. 2 (April 2013): 21–38. http://dx.doi.org/10.4018/jdwm.2013040102.

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In a typical BI infrastructure, data, extracted from operational data sources, is transformed, cleansed, and loaded into a data warehouse by a periodic ETL process, typically executed on a nightly basis, i.e., a full day’s worth of data is processed and loaded during off-hours. However, it is desirable to have fresher data for business insights at near real-time. To this end, the authors propose to leverage a data warehouse’s capability to directly import raw, unprocessed records and defer the transformation and data cleaning until needed by pending reports. At that time, the database’s own processing mechanisms can be deployed to process the data on-demand. Event-processing capabilities are seamlessly woven into our proposed architecture. Besides outlining an overall architecture, the authors also developed a roadmap for implementing a complete prototype using conventional database technology in the form of hierarchical materialized views.

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