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171.
虽然整数规划中经典的Lagrange对偶方法是一个有效的方法,但是由于对偶缝隙的原因它经常不能求出原问题的最优解。该文提出一个用于有界整数规划的指数对偶公式。此公式具有渐进强对偶的特性并且可以保证找到原问题的最优解。它的另一个特性是当参数选择的合适时不需要进行实际的对偶搜索。 相似文献
172.
Quasi-interpenetrating network (IPN) formed by polyacrylamide and poly(N,N-dimethylacrylamide) was designed, synthesized, and tested as a high-performance DNA separation medium by capillary electrophoresis. The performance of quasi-IPN on DNA sequencing was determined by the acrylamide to dimethylacrylamide molar ratio, polyacrylamide molecular weight, and its size distribution. Under optimal operating conditions, quasi-IPN was able to achieve one-color DNA sequencing up to 1000 bases in 39 min, or 1200 bases in 60 min. Its performance was compared with some of the existing commercialized products, such as POP6 from Applied Biosystems and MegaBACE matrix from Amersham Biosciences. By using the ABI 310 Genetic Analyzer, even without optimized base-calling software, quasi-IPN yielded a read length of up to 700 bases of contiguous sequence (50-750 bases) in 35 min with 99.6% accuracy, or 750 bases of contiguous sequence (50-800 bases) in 37 min with 98.0% accuracy. 相似文献
173.
We analyze quasi-phase-matched (QPM) conversion efficiency of the five possible types of periodic two-dimensional nonlinear
structures: Hexagonal, square, rectangular, centered-rectangular, and oblique. The frequency conversion efficiency, as a function
of the two-dimensional quasi-phase-matching order, is determined for the general case. Furthermore, it is demonstrated for
two basic feasible motifs, a circular motif and a rectangular motif. This enables to determine the optimal motif dimensions
for achieving the highest conversion efficiency. We find that a rectangular motif is more efficient than a circular motif
for quasi-phase-matched processes that rely on a single reciprocal lattice vector (RLV), and that under optimal choice of
motif dimensions, it converges into a one-dimensional periodic structure. In addition, in a few specific cases we found that
higher order QPM can be significantly more efficient than lower order QPM. 相似文献
174.
We demonstrate stochastic decomposition structures of the queue length and waiting time in an M/M/1/WV queue, and obtain the distributions of the additional queue length and additional delay. Furthermore, we discuss the relationship between the stochastic decomposition properties of the working vacation queue and those of the standard M/G/1 queue with general vacations. 相似文献
175.
The velocity of an incompressible flow in a bounded three‐dimensional domain is represented by its vorticity with the help of an apparently new representation formula. Using this formula we prove a quasi‐Lipschitz estimate for in dependence of the supremum norm of . Our quasi‐Lipschitz bound extends to the case where is represented by any continuous ≠ rot 相似文献
176.
This paper elaborates a nonlinear fluidic low frequency vibration isolator designed with the characteristics of quasi-zero stiffness (QZS). The existing
model of QZS vibration isolator enhances amplitude of vibration and attenuating
vibration frequencies. This concern with displacement plays a vital role in the performance and instability of oblique spring setup reduces the isolator performance
in horizontal non-nominal loads, in this accordance; this paper associates double
acting hydraulic cylinder (fluidic actuators in short) in oblique and helical coil
spring. An approximate expression of unique analytical relationship between
the stiffness of vertical spring and bulk modulus of the fluid is derived for Quasi
– Zero Stiffness Non-Linear Vibration Isolator with Fluidic Actuators (NLVIFA in
short) system and the force transmissibility is formulated and damping ratio are
discussed for characteristic analysis. Modal analysis carried out and compared
with analytical results and an experimental prototype is developed and investigated. The performance of the NLVIFA reduces the external embarrassment more
at low frequencies and the series of experimental studies showing that the soft
nonlinearity causes limitation in the resonant frequency thereupon the isolation
will be enhanced and NLVIFA greatly outperform some other type of nonlinear
isolators. 相似文献
177.
178.
邓方文 《数学物理学报(A辑)》2000,20(Z1):699-701
定义了拟有理映照的Fatou集,将有理映照的部分结果推广到拟有理映照,并提出了供进一步研究的问题. 相似文献
179.
Antje Brucks 《Archive of Applied Mechanics (Ingenieur Archiv)》2008,78(1):33-47
Experimental results are presented on natural convection in a spherical shell of inner and outer radii r
1 = 14 mm and r
2 = 35 mm, with the inner sphere cooled and the outer sphere heated. The fluids filling the shell are two different silicon
oils having Prandtl numbers 39 and 233. Both spheres are fixed together and can be rotated. In the studied regime, both Coriolis
and centrifugal forces become significant. For sufficiently small Rayleigh numbers the resulting flow pattern is axisymmetric
and steady, consisting of a plume descending from the south pole of the inner sphere, and returning in the equatorial regions.
For greater Rayleigh numbers the flow becomes non-axisymmetric, with azimuthal modes m = 2 to 4 arising. We map out the critical Rayleigh number for the onset of these different modes, and consider how they vary
with increasingly rapid overall rotation. Detailed flow measurements are done by converting a standard 2D particle image velocimetry
system into a scanning quasi-3D PIV system. 相似文献
180.