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991.
本文得到了生灭过程和一维扩散过程满足Nash不等式的判别准则,并证明 了对此二类过程,非常返性蕴含相应半群如下收敛速度||P(t)||1→∞≤Ct-1.同时也给 出一般马氏链满足Nash不等式的充分条件. 相似文献
992.
W
adys
aw Kulpa 《Topology and its Applications》2003,130(3):33-258
If f maps continuously a compact subset X of Rn into Rn and x is a point whose distance from the boundary ∂X is greater than double diameter of the fibres of the points in f(∂X) then f(x) is in the interior of f(X). This theorem extends some results due to Borsuk and Sitnikov. 相似文献
993.
视频图像记录判读系统 总被引:6,自引:0,他引:6
光电经纬仪的摄影胶片图像和CCD摄像机的视频图像的数字化处理是兵器试验靶场中始终未能很好解决的问题。主要源于两个问题:一是视频图像的数字化采集和转换;二是数字图像的自动处理。介绍了根据靶场广泛应用的光学图像记录、判读需求而研制的视频图像记录判读系统,并对所采用的视频图像实时存储技术、字符识别技术、目标识别与定位技术等几项主要的关键技术进行了说明,并给出了应用结果。结果表明,图像采集记录灵活方便,速度快,不丢帧;目标图像处理精度高,实时性强,自动处理能力好,使光测数据处理的精度和效率都有了很大的提高。 相似文献
994.
995.
Jooyeon Hong 《Tetrahedron letters》2007,48(8):1327-1330
The first theoretical study on the conformational features and the complexation behaviors upon ammonium ion binding of tetrahomodioxacalix[4]biscrown-4 has been performed using molecular dynamic simulations and density functional theory. The conformational analyses show that the relative stability and the geometry of the ammonium ion complexes are directly contributed by the number of putative hydrogen bonds between oxygen lone pairs and ammonium hydrogens. 相似文献
996.
A new relation for the density parameter Ω is derived as a function of expansion velocity υ based on Carmeli's cosmology.
This density function is used in the luminosity distance relation D
L. A heretofore neglected source luminosity correction factor (1 − (υ/c)2)−1/2 is now included in D
L. These relations are used to fit type Ia supernovae (SNe Ia) data, giving consistent, well-behaved fits over a broad range
of redshift 0.1 < z < 2. The best fit to the data for the local density parameter is Ωm = 0.0401 ± 0.0199. Because Ωm is within the baryonic budget there is no need for any dark matter to account for the SNe Ia redshift luminosity data. From
this local density it is determined that the redshift where the universe expansion transitions from deceleration to acceleration
is z
t = 1.095+0.264
−0.155. Because the fitted data covers the range of the predicted transition redshift z
t, there is no need for any dark energy to account for the expansion rate transition. We conclude that the expansion is now
accelerating and that the transition from a closed to an open universe occurred about 8.54 Gyr ago. 相似文献
997.
998.
Masakazu Yoshikawa Katsunori Koso Kyoichi Yonetani Satoshi Kitamura Satoshi Kimura 《Journal of polymer science. Part A, Polymer chemistry》2005,43(2):385-396
Molecularly imprinted polymeric membranes were prepared from various oligopeptide tweezers by the adoption of N‐α‐tert‐butoxycarbonyl‐D ‐tryptophan (Boc‐D ‐Trp) or N‐α‐tert‐butoxycarbonyl‐L ‐tryptophan (Boc‐L ‐Trp) as a print molecule. The chiral recognition ability of the formed molecular recognition sites was dependent on the absolute configuration of the print molecule adopted in the membrane preparation (molecular imprinting) process, whereas the candidate oligopeptide tweezers consisted of the L ‐amino acid residues. In other words, the membranes imprinted by the D ‐isomer recognized the D ‐isomer in preference to the corresponding L ‐isomer, and vice versa. The affinity constant between the target molecule and the chiral recognition site from the oligopeptide tweezers was higher than that from a single‐strand oligopeptide derivative. Those membranes selectively transported the enantiomer, which was preferentially incorporated into the membrane by dialysis. The permselectivities for these membranes exceeded their adsorption selectivities. © 2004 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 43: 385–396, 2005 相似文献
999.
1000.
A thiourea-based tripodal colorimetric anion sensor was synthesized. Its binding abilities with AcO^- and halide anions in DMSO were studied by UV-Vis spectra. The sensor showed different color responses to these anions. The association constants and different stoichiometries were deduced by nonlinear least-square curve fitting or linear fitting. 相似文献