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221.
222.
223.
We construct functions Mα which are piecewise homogeneous polynomials on the (d+1)-dimensional torus Ud+1. These functions possess complete symmetry with respect to the independent variables. The symmetry and homogeneous relations
for these functions are exploited to obtain a recurrence relation and explicit representations. Furthermore, we show that
, where ω=e12x/k, 0≤jt≤k−1, are linearly independent. By restricting Mα to Ud, we obtain the complex analogue of polynomial box splines on a (d+1)-direction mesh on Ud, which is a multivariate analogue of B-splines on the circle studied by I.J. Schoenberg[8]. 相似文献
224.
Karen A. Lee Margaret A. Frerking 《Journal of Infrared, Millimeter and Terahertz Waves》1989,10(7):789-802
A quasi-optical reflection cavity intended to be used as the resonant load of a submillimeter wavelength oscillator has been designed, constructed, and tested. The resonator consists of three elements in cascade: a high Q, high finesse folded Fabry-Perot resonator, a lower Q, low finesse Fabry-Perot resonator, and a Littrow mounted diffraction grating. The resonator exhibits a Q of 6600 and 2.5 dB of loss at 63 GHz. The design can be scaled to 1 THz, where waveguide structures become impractical, to serve as the resonator for high frequency quantum well resonant tunneling device oscillators. 相似文献
225.
226.
Lee SH 《Physical review D: Particles and fields》1989,40(7):2484-2486
227.
The neutron irradiated potassium hexacyanoferrate(III) solutions were analyzed for Fe(CN)64?, Fe(CN)63?, and Prussian blue. The retention values (1.1%) were constant throughout the pH and concentration ranges studied, and did not change with the length of irradiation. The complex behavior of the radiochemical yield of the Fe(CN)64? and Prussian blue was attributed to the competition of the various reactions involved in the irradiation. 相似文献
228.
Wright RC Riederer SJ Lee JN Farzaneh F De Castro JB 《IEEE transactions on medical imaging》1987,6(2):165-168
This work presents methods for estimating relaxation times T1 and T2 and proton density using a real time digital video processor. This device performs each mathematical step of the fitting algorithms in one video frame interval (1/30 s). Two-point fits of T1 and T2 may be generated in approximately 15 video frame intervals or about 0.5 s; generation of a T2 image from four acquired images requires about 30 video frame intervals or about 1 s. The hardware is common to many commercial MR scanners and requires no array processor. Such high-speed techniques can expedite the clinical use of computed images and facilitate the implementation of image synthesis. 相似文献
229.
230.
It is conceivable that the high-T
c
superconducting perovskites are conventional electronphonon superconductors. In this case one expects significant strong-coupling effects because of the unusually high ratiok
B
T
c
/ of the order 0.1 and greater. We use a set of reasonable models for the Eliashberg function 2
F() (which takes into account available information on the phonon spectra and which fit the measuredT
c
's) and calculate strong-coupling effects in the specific heatc
s
(T)/T
c
, the ratio 0/k
B
T
c
, the critical fieldsH
c
(T) andH
c2
(T) including Pauli limiting, and other measurable quantities. Strongcoupling corrections turn out to be in the range of 0 to about 100%, depending on the quantity of interest. We discuss the perspectives of using strong-coupling effects as indicators for conventional electron-phonon superconductivity in the new materials. 相似文献