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101.
102.
The solution behaviour of a new mesogenic side group polyacrylate in tetrahydrofuran and toluene has been investigated by static and dynamic light scattering. In the dilute regime the polymer behaves as typical polydisperse linear chains in good solvent and the dynamics is dominated by a single fast mode. Cluster formation was detected starting at a concentration around 50 g l−1. It seems to be independent of the solvent as well as of polymer molecular weight. In the semidilute regime, the behaviour of the reduced osmotic modulus leads to the conclusion that repulsion between the chains is stronger than in linear macromolecules. The appearance of larger clusters was revealed above a characteristic concentration and is slightly dependent on the polyacrylate molecular weight. The dynamics was generally characterised by a fast mode related to the cooperative diffusion and by a slow mode associated with large clusters. The existence of a network of multiconnected clusters is envisaged with increasing solution concentration. 相似文献
103.
Oils in Jinghu sag are abundant with high content of polar compounds and have a low ratio of saturate to aromatic hydrocarbons and a high ratio of resin to asphaltene. The gross composition of oils in the Jinghu sag suggests typical immature to low mature characteristics. Some compounds with low thermal stability were identified. Light hydrocarbons, a carbon preference index, an odd even index, n-alkane and hopane maturity parameters show mature features and little differences in the maturity level among oils. Sterane isomerization parameters indicate an immature to low mature status of oil. Transfer of the sedimentary center during sedimentation has led to different thermal histories among subsags and thus generated oils with different maturities. On the basis of source analyses, four migration and accumulation patterns with different maturity can be classified. Combined with available information on mergers of source, reservoir and long distance oil lateral migration, mixing conditions were present in the Jinghu sag. Experimental results indicate that maturity variations are caused by mixtures of hydrocarbons with different maturity. 相似文献
104.
Evaluation of rainfall networks using entropy: II. Application 总被引:2,自引:0,他引:2
This paper, the second in the series, applies the entropy approach to space and time evaluation of rainfall networks in Louisiana. The evaluation is made for five sampling intervals: daily, 2-day, weekly, monthly, and yearly, and for two separate seasons. In each case, the best combination of raingages is suggested and the lines of equal information (isoinformation contours) are constructed showing the areas of greater or less information transfer. The isoinformation lines are especially suitable in decisions concerning the expansion of the existing network or deleting the unnecessary raingages. 相似文献
105.
R. S. Fyath K. N. Darraj M. S. Alam M. N. Islam M. M. Alkhatib 《Optical Memory & Neural Networks》2007,16(3):125-135
A new joint transform correlation (JTC) technique, named two-channel JTC (TJTC), is proposed in this paper for optical pattern
recognition applications. The TJTC technique independently evaluates the autocorrelation and crosscorrelation values of the
reference and the target images and employs a modified decision algorithm. In addition, optical threshold operation and fringe-adjusted
filter are incorporated in the proposed technique to enhance the correlation output and to improve the discrimination performance.
The proposed technique shows better recognition performance compared to existing JTC techniques. Computer simulation are presented
to investigate the salient features of the proposed TJTC technique with noise-free as well as noisy input scenes.
The text was submitted by the authors in English. 相似文献
106.
万安水利枢纽底孔坝段中隔墙流激振动响应分析 总被引:3,自引:0,他引:3
研究了万安水利枢纽底孔坝段中隔墙在水流脉动壁压作用下的结构随机振动问题,进行了一种泄流工况下的隔墙结构流激振动响应统计量的理论计算,模拟计算了隔墙-水流-基础耦合系统固有频率对流激振动响应的影响,并对水流脉动壁压随机荷载作用下的结构动力可靠度进行了理论分析。 相似文献
107.
V. M. Kravtsov 《Cybernetics and Systems Analysis》2007,43(1):25-33
It is proved that, for any r ∈ { 2n, 2n + 1,…, 3n−2} and only for such r, the polytope of a three-index axial assignment problem
of order n, n ≥ 2, contains completely r-noninteger vertices (r-CNVs), i.e., vertices such that all their positive components
are fractional and their number equals r. For each r ∈ {2n, 2n + 1,…, 3n −2}, all the types of r-CNVs are characterized and
the combinatorial properties of completely r-noninteger vertices of the polytope are studied.
__________
Translated from Kibernetika i Sistemnyi Analiz, No. 1, pp. 33–44, January–February 2007. 相似文献
108.
Gordon J.R. Povey 《Wireless Personal Communications》1998,8(2):151-164
A hybrid correlator architecture is described which combines the serial structure of an active correlator with the parallel structure of a matched filter correlator. The mean PN code acquisition time performance of this hybrid serial-parallel correlator structure is analysed. Results are shown which compare the acquisition performance of the serial, parallel, and serial-parallel structures. The results are for a PN code length of 64 code chips and assumes a Gaussian channel with the receiver detection threshold set to obtain a constant false alarm rate. An enhancement to the serial-parallel acquisition algorithm is also described which can increase the acquisition time performance by about 15% for typical operating conditions. Overall the results demonstrate that the hybrid correlator can provide rapid code acquisition with a limited receiver complexity. 相似文献
109.
110.
巡航导弹机动地形相关系统 总被引:1,自引:0,他引:1
研究了一种适用于巡航导弹辅助导航的机动地形相关系统(MTCS)。介绍了 MTCS的工作原理、相关定位算法以及提高定位概率的技术途径,指出了系统设计中的关键技术。另外还讨论了 MTCS 的计算机运算,研究结论对地形辅助系统的设计有参考价值。 相似文献