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61.
用矩阵方法,求解McCreary和Fickian铅垂向湍扩散形式下,无界海洋条件时在风应力和深层浮力作用下的线性解。得出不同的湍扩散系数A情况下McCreary与Fickian湍扩散形式的流场结构。指出随湍扩散系数的增加,McCreary和Fickian湍扩散形式下u分量结构及其量值差异增大。在Fickian湍扩散形式下,能量穿越密度跃层的传递能力较强。当A=0.1cm~2s~(-3)时,在风应力和深层浮力作用下两种湍扩散形式造成流场的差异很小。提出在小湍扩散系数下,用McCreary湍扩散形式研究热带海洋环流,其结果和Fickian形式应相当一致。 相似文献
62.
Sequence variation of the first internal transcribed spacer of ribosomal DNA ( ITS - 1 ) was examined and its application to the study of genetic variation was explored in four populations of farter' s scallop Chlamys farreri. ITS - 1 fragments, with a length of about 300 bp,of 78 individuals collected from Dalian, Qingdao, Yantai in China and Korea respectively were amplified via PCR, cloned and sequenced. Intra-genomic variation was examined by sequencing several clones of single individuals. Alignment and polymorphism analysis detected 44 haplotypes and 50 polymorphic sites which consist of 30 substitutions and 20 indels, indicating a high level of polymorphisms. Sequence analysis also showed a very low level of intra-individual variation. All these features validated the feasibility of application of ITS - 1 fragment to population analysis. Polymorphism analysis showed that the Korea sample has the richest genetic variation, followed by Yantai and Qingdao samples. AMOVA (analysis of molecular variance) showed that the majority (96.26%) of genetic variation was distributed within populations and 3.74% resulted from among populations, but with P 〈 0.05 ( = 0.042), indicating that the populations in this study have significant divergence. This output was basically concordant with the result arising from RAPD data and different from that from mitochondrial 16S rDNA sequence data. Discussion on this inconsistency was made accordingly. 相似文献
63.
Non-Simultaneous Failure of Ice in Front of Multi-Leg Structures 总被引:4,自引:1,他引:4
Because the multi-leg jacket structure is the major type of offshore structures in the Bohai Sea, the study of non-si-multaneous failure of i鏴 on multi-leg structures is important. However, the non-simultaneous failure has not been consid-ered in engineering design until now, obviously resulting in costly design and notable waste. To resolve this problem, this paper, by means of analysis of experimental data, calculates the coefficient of the non-simultaneous failure for the double-pile structure, the square four-leg structure, the single-line multi-pile structure, and the conical structure, respectively, and provides some reference criteria for engineering design. 相似文献
64.
Ocean Waves: Half-a-Century of Discovery 总被引:1,自引:0,他引:1
Paul H. LeBlond 《Journal of Oceanography》2002,58(1):3-9
While the nature of most ocean waves has long been known and their basic physics understood since the nineteenth century,
intense study of ocean waves during the second half of the twentieth century has taken the subject from the realm of mathematical
exercises to that of practical engineering. Modern understanding of the generation, propagation and interactions of ocean
waves with each other and with oceanic features has advanced to a quantitative level offering predictive capacity. This paper
presents a brief qualitative review of advances in knowledge of sound waves, wind waves, tsunamis, tides, internal waves and
long-period vorticity waves. The review is aimed at non-specialists who may benefit from an overview of the current state
of the subject and access to a bibliography of general-interest references.
This revised version was published online in August 2006 with corrections to the Cover Date. 相似文献
65.
66.
67.
C.H.K. Williamson 《Applied Ocean Research》1985,7(3):124-127
The present brief paper is intended to show that the fluid forces on a small cylinder can be considerably magnified when it is in the flow field of a larger cylinder. Two cylinders of unequal diameter are oscillated in a tank of fluid, and the lift and in-line forces on the smaller cylinder are measured when the pair of cylinders is placed at various orientations and spacings. 相似文献
68.
A preliminary theoretical and experimental study was conducted on internal wave modes and their weak nonlinear resonant interaction
in a nonlinearly stratified fluid. An asymptotical solution of the modes and a dispersion relation of internal waves in a
stratified fluid with density profile
similar to that in our experiment were obtained theoretically. The resonant-interaction mechanism to 2nd order approximation
is also discussed. The resonant interaction of the 3rd and 4th mode internal waves excited by the unstable 1st mode wave is
analyzed on the basis of data obtained by conductivity probes. The resonant-interaction condition, i.e.,
,k
1+k
3+k
4=0, is examined. It is shown that the resonant instability increases with pycnocline thickness and wave maker driving frequency.
This work is supported by the National Natural Science Foundation of China. 相似文献
69.
70.
某基坑工程土钉支护工作性状试验研究 总被引:1,自引:0,他引:1
通过对广州天河荟雅苑基坑工程土钉支护进行试验和研究,分析了土钉支护体系的工作性状,并为同类工程的设计提供了一定的依据。 相似文献