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Avihai Ron Sandeep Kumar Kalva Vijitha Periyasamy Xosé Luís Deán-Ben Daniel Razansky 《Laser u0026amp; Photonics Reviews》2021,15(3):2000484
Tracking of biodynamics across entire living organisms is essential for understanding complex biology and disease progression. The presently available small-animal functional and molecular imaging modalities remain constrained by factors including long image acquisition times, low spatial resolution, limited penetration or poor contrast. Here flash scanning volumetric optoacoustic tomography (fSVOT), a new approach for high-speed imaging of fast kinetics and biodistribution of optical contrast agents in whole mice that simultaneously provides reference images of vascular and organ anatomy with unrivaled fidelity and contrast, is presented. The imaging protocol employs continuous overfly scanning of a spherical matrix array transducer, accomplishing a 200 µm resolution 3D scan of the whole mouse body within 45 s without relying on signal averaging. This corresponds to an imaging speed gain of more than an order of magnitude compared with existing state-of-the-art implementations of comparable resolution performance. Volumetric tracking and quantification of gold nanoagent and near infrared (NIR)-II dye kinetics and their differential uptake in various organs are demonstrated. fSVOT thus offers unprecedented capabilities for multiscale imaging of pharmacokinetics and biodistribution with high contrast, resolution, and speed. 相似文献
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Z. Kalva 《Czechoslovak Journal of Physics》1969,19(4):488-493
The appearance of two resonant modes of spin waves with different non-zero wave vectors is theoretically predicted for a magnetic arrangement of the type of an antiferromagnetic spiral combined with weak antiferromagnetism in the direction of the spiral axis. A study is made of the question of the Hamiltonian suitable for possible applications of the chosen magnetic arrangement, and the possibility of energetic stability of the considered magnetic structure for two concrete realistic forms of the Hamiltonian is pointed out.The author expresses his sincere thanks for valuable discussions and stimulating comments to Dr. S. Krupika and Dr. J. Loos, P. Novák and I. Veltruský of the Institute of Solid State Physics of the Czechoslovak Academy of Sciences, and to Assoc. Prof. J. Morkowski and Assoc. Prof. L. Kowalewski of the Polish Academy of Sciences and Poznan University. 相似文献
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VC-1 is a new video coding standard developed by Microsoft and standardized by the SMPTE. VC-1 is one of the three video compression algorithms standardized for high definition DVD. With high definition DVD players expecting to support MPEG-2, H.264, and VC-1, end users do not have to be concerned about the coding formats. The VC-1 standard offers a competitive quality-complexity tradeoff compared to H.264, especially for high-definition services. With a diverse digital video market, we can expect to see VC-1 co-existing with H.264 in the next generation of broadband and broadcast video services. 相似文献
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Grandhi Venkata Subrahmanyam;Kalva Sri Rama Krishna; 《International Journal of Communication Systems》2024,37(1):e5632
A compact and novel ultrawideband (UWB) antenna integrated with Ku band for microwave imaging applications is reported. The reported antenna consists of a novel patch structure along with a tapered feed structure on top of FR-4 substrate having a compact dimension of 16 × 22 mm2 and novel semicircular defected ground structure (SC-DGS) etched below the substrate. The proposed antenna covers a wide impedance bandwidth of 15.07 GHz spanning from 3.51 to 18.58 GHz with a fractional bandwidth (FBW) of 136%. The intended antenna performance is analyzed for S11, peak gain, efficiency, and radiation patterns in frequency domain, and group delay, isolation (S21), and linear phase response in time domain. The simulated and measured results of reported antenna are well matched for the usage in practical portable UWB applications. More importantly, the proposed antenna system is simulated for the detection of breast cancer tissue by comparison of S21 results, current densities, and specific absorption rate with and without tumor conditions. These findings show that the radiator and the whole system work well in detecting the breast tumor. 相似文献
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The modeling of magnetocaloric effect (MCE) based on quasiparticle formalism was used to show a possibility to increase our
knowledge of diffusion and phase transitions by a transdisciplinary scientific approach. Generalized understanding of diffusion
and of some phase transitions was suggested. New relations between MCE and elastic parameters of materials, obtained from
modeling procedure, were presented. The paper contains also the short discussion of a necessity to use hypercomplex mathematics
in modeling of magnetic processes and specifically in a modeling of MCE. Some remarks concerning nanomaterials are added.
This revised version was published online in August 2006 with corrections to the Cover Date. 相似文献
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Z. Kalva 《Czechoslovak Journal of Physics》1972,22(11):1056-1066
The contribution of this work is the extension of Green's function formalism to the case of noncollinear, canted, 6-sublattice magnetic structure. The external magnetic field was considered. The selfconsistent procedure for calculation of renormalized spin-wave energies and the mean value of the Hamiltonian was discussed on the basis of both Tyablikov's and Callen's decoupling approximations and it was shown that the use of Callen's decoupling requires a preliminary solution of the problem on the basis of simpler decoupling. The equations are analogous to the Callen's equation but the temperature dependent factor has a more general form and instead of an explicit equation for energy there is an implicit equation. 相似文献
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Computer studies are made illustrating the similarities of the interesting change of sign in the magnetocaloric effect between the vortex lattice in superconductors and a system of interacting magnons and phonons in ferromagnetic materials. This change happens in the superconducting system when the external magnetic field approaches a critical value, while the critical point in the ferromagnetic system is where the external magnetic field turns the direction of magnetization from the easy to the hard direction. The usefulness for the study of high-temperature superconductors is suggested. 相似文献
10.
The H.264 video coding standard, also known as MPEG AVC, represents the state of the art in video compression. This article provides an overview of the H.264 standard. To help the reader understand the similarities and differences between it and MPEG-2 (and other hybrid video coding standards), the author describes the H.264 features and compare them to functionally similar MPEG-2 features 相似文献