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991.
Doo-Hee Chang Seung-Ho Jeong Bong-Guen Hong Kyu-Sun Chung Gon-Ho Kim Jae-Shin Lee 《Current Applied Physics》2001,1(6):497
The radial profiles of KT-1 tokamak (major radius of 27 cm, minor radius of 4.25 cm, two poloidal stainless-steel limiters) edge plasma parameters are measured using single and triple electric probes. The particle transport parameters are calculated from the measured edge plasma parameters, and the results are analyzed by the simple fluid approximations. The cross-field particle diffusion coefficient (D) in the boundary plasma of the KT-1 is calculated from the density scrape-off length (λn) measured by using a triple probe. The particle density and electron temperature fall exponentially in the radial direction with the e-folding length of λn=0.13 cm and λe=0.41 cm, respectively. From the scrape-off layer (SOL) model, the experimental values of scrape-off length (λn) is used to calculate the cross-field diffusion coefficient (D=1.2×103cm2/s), roughly corresponding to one third of the typical Bohm value. A simple SOL model with the contribution of recombination is introduced to evaluate the Bohm diffusion in the KT-1 tokamak edge plasma. Cross-field heat conductivity calculated from these deduced values is 5.2D in the SOL of KT-1 edge plasma. These results provide the finally certain information for edge particle transport in the KT-1 boundary plasmas. 相似文献
992.
Soon-Yeong Chung Dohan Kim Eun Gu Lee 《Proceedings of the American Mathematical Society》2000,128(8):2421-2430
Every periodic hyperfunction is a bounded hyperfunction and can be represented as an infinite sum of derivatives of bounded continuous periodic functions. Also, Fourier coefficients of periodic hyperfunctions are of infra-exponential growth in , i.e., for every and every . This is a natural generalization of the polynomial growth of the Fourier coefficients of distributions.
To show these we introduce the space of hyperfunctions of growth which generalizes the space of distributions of growth and represent generalized functions as the initial values of smooth solutions of the heat equation.
993.
For optimally doped Bi(2)Sr(2)CaCu(2)O(8+delta), scattering rates in the normal state are found to have a linear temperature dependence over most of the Fermi surface. In the immediate vicinity of the (pi, 0) point, the scattering rates are nearly constant in the normal state, consistent with models in which scattering at this point determines the c-axis transport. In the superconducting state, the scattering rates away from the nodal direction appear to level off and become temperature independent. 相似文献
994.
A magnetic field applied parallel to the two-dimensional hole system in the GaAs/AlGaAs heterostructure, which is metallic in the absence of an external magnetic field, can drive the system into insulating at a finite field through a well-defined transition. The value of resistivity at the transition is found to depend strongly on density. 相似文献
995.
R. Unanyan S. Guérin B. W. Shore K. Bergmann 《The European Physical Journal D - Atomic, Molecular, Optical and Plasma Physics》2000,8(3):443-449
In traditional schemes of multilevel multilaser excitation, each laser pulse interacts with only one pair of states, and the
rotating wave approximation (RWA) is applicable. Here we study the population transfer process in a three-state system when
each of the two lasers interacts with each of the pair of states and when the Rabi frequencies characterizing the interaction
strengths of the system are comparable to or larger than the difference of the transition frequencies. We show that complete
and robust population transfer is possible under conditions more general than those hitherto considered necessary for stimulated
Raman adiabatic passage (STIRAP) or for successive π pulses. Using adiabatic Floquet theory we show that successful population transfer can be interpreted as adiabatic passage
by means of a transfer state which connects the initial and final states. The Floquet picture offers a convenient interpretation
of the population transfer as accompanied by multiple absorption of photons from or emission into the laser fields. 相似文献
996.
光声成像结合了光学成像和声学成像的优点,是一种高分辨率,高对比度的无损伤医学成像技术.一种改进的同步迭代算法应用于光声图像重建.仿真和模拟结果表明,与传统的代数迭代算法相比,在90°,135°,180°的有限场光声成像中,此算法对测量误差的校正和迭代次数的收敛上具有较大的优势,图像重建的速度和成像质量都有了明显的提高.实验中,一种圆形扫描结构的光声成像装置,用于180°的有限场扫描,利用改进的同步迭代算法,重建出了高对比度和高分辨率(60μm)的鸡胚胎光声血管图像.实验证明,这种算法的应用,大幅度减少了数据采集时间,为光声成像技术运用于实时监测血流灌注和肿瘤光动力治疗的血管损伤效应提供了潜在的应用价值.
关键词:
光声成像
有限角度
代数迭代算法
光声血管成像 相似文献
997.
998.
999.
1000.
Sub Hur Hodeok Jang Yonghoon Kim Hanlim Lee Seongtaek Hwang Yunje Oh Y. J. Sung Y. S. Kim Jichai Jeong 《Optical and Quantum Electronics》2007,39(7):561-569
We investigate the performance limits of a pico-cell system using the radio- over-fiber technique with an electroabsorption
modulator (EAM) in a 2.4 GHz wireless local area network (WLAN) environment. To understand the performance limits of the system
using an EAM as the optical transceiver, we vary the optical modulation index (OMI) of the transmitter for different bias
voltages to the EAM. Power margins in the links are found to estimate a possible service range, and packet loss rates (PLRs)
in the pico-cell system are measured to evaluate the transmission performance. The total service range can be extended up
to 3 m by adjusting the OMI of the transmitter for different applied bias voltages to the EAM. 相似文献