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Wen Shengchang 《海洋学报(英文版)》1988,7(3):325-343
The method developed by Wen et al. (1988 a) for deriving theoretical wind wave frequency spectrum in deep water is extended to the case of water of finite depth, in which a parameter η=H/d is introduced, where H and d represent the average wave height and water depth respectively. The derived spectra reduce to those in deep water when η=0. The case of η=1/2 corresponds to waves impending to break because of the effect of the bottom. Simplified forms of spectra are given. The theoretical results agree with the observed spectra well. 相似文献
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Wen Shengchang 《海洋学报(英文版)》1988,7(1):1-16
In this part ot the paper theoretical wind-wave spectra nave been derived oy (I) expressing the spectrum in series composed of exponential terms; (2) assuming that the spectrum satisfies a high order linear ordinary differential equation; (3) introducing proper parameters in the spectrum; and (4) making use of some known charateristics of wind-wave spectrum, for instance, the law governing the equilibrium range. The spectrum obtained contains the zero order moment of the spectrum m0, the peak frequency ω0 and the ratio R =ω/ω0 (ω being the mean zero-crossing frequency) as parameters. The shape of the nondimensional spectrum S(ω) = ω0S(ω)/m0(ω=ω/ω0) changes with R and theoretically reduces to a Dirac delta function δ(ω-1) when R = 1. A spectrum of simplified form is given for practical uses, in which R is replaced by a peakness factor P=S(1). 相似文献
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Aproposeddirectionalfunctionandwind-wavedirectionalspectrum¥WenShengchang;WuKejian;GuanChanglong;SunShicaiandZhangDacuo(Recei... 相似文献
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Improved form of wind wave frequency spectrum 总被引:5,自引:0,他引:5
Wen Shengchang 《海洋学报(英文版)》1989,8(4):467-483
The lower frequency part of the theoretical wind wave spectrum proposed by the authors (Wen et al. , 1988a, b,c) has been improved and the form of spectrum is appreciably simplified. In addition to the field data collected in the Bohai Sea region and used in the previous papers, those obtained in the Huanghai Sea, the East China Sea and the South China Sea have been employed so that the improved spectra can be verified on a more extensive observational basis. Computed results agree with the observations well. Further comparisons have been made between the proposed spectra and the JONSWAP spectrum. Though the two types of spectrum are close to each other in form, the former shows, as a whole, better agreement with the observation than the latter. By introducing an improved relation between the peak-ness factor and significant wave steepness, the spectrum contains only significant wave height and period as parameters. For spectra given in this form, the computed peak frequencies coincide approximately wit 相似文献
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目的:观察不同剂量的补肝健腰方对大鼠腰椎间盘退变组织碱性成纤维细胞生长因子(bFGF) mRNA表达的干预作用。方法:将130只雄性SD大鼠随机分为正常对照组20只、假手术组20只、造模组90只,采用椎间盘穿刺造模方法制备大鼠腰椎间盘退变模型,将造模成功的80只大鼠随机分为补肝健腰方低、中、高剂量组及模型组,每组各20只,分别采用补肝健腰方低剂量(含生药1.04 g)、中剂量(含生药2.08 g)、高剂量(含生药4.16 g)、0.9%氯化钠注射液灌胃,检测各组干预前及干预2、4、6周后椎间盘退变组织bFGF mRNA的表达,并进行对比分析。结果:1)假手术组与正常对照组比较,2组各时间点bFGF mRNA的表达差异均无统计学意义(P>0.05)。2)模型组与正常对照组比较,2组各时间点bFGF mRNA的表达差异均具有统计学意义(P<0.05)。3)给药组与模型组比较,干预前及干预2周后各给药组与模型组bFGF mRNA的表达差异无统计学意义(P>0.05);干预4、6周后各给药组的bFGF mRNA表达均较模型组降低,差异具有统计学意义(P<0.05)。4)各给药组组间比较,干预4、6周后中、高剂量组较低剂量组bFGF mRNA的表达均下降,差异具有统计学意义(P<0.05或P<0.01)。结论:不同剂量的补肝健腰方均能下调腰椎间盘退变模型大鼠椎间盘中bFGF mRNA的表达,中、高药物剂量组作用更加显著。 相似文献
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measurements by a circular array consisting of 18 wave gauges in a large wave tank, directional spectra of wind-generated waves in deep water are systematically determined by using maximum likelihood method The investigations reveal that the angular spreading of the wave energy is consistent with cos2s(θ/2) proposed by Longuet-Higgins et al.(1963, Ocean Wave Spectra, 111-136), if the bimodal distributions of wave energy are not taken into account. Bimodality occurring on higher frequency than peak frequency is too rare to affect our whole resalts. Surprisingly, a much broader directional spreading than that of the field, which is interpreted by the strongly nonlinear energy transfer because of the very young waves in laboratory, is found. The parameter s depends on frequency in the same way as observed by Mitsuyasu et al.(1975, Journal of Physical Oceanography, 5, 750-760) and Hasselmann et al.(1980, Journal of Physical Oceanography, 10, 1264-1280) in the field, and the relationship between the four nondimensional parameters sm, fo, b1 and b2, determining the directional width, and ū10 (corresponding to the inverse of wave age) are given respectively. The observed distributions are found to agree well with the suggestion of Donelan et al.(1985, Philosophical Transaction of Royal Society of London, A315, 509-562) when applied to field waves. 相似文献
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以东北地区的地学断面及其相关资料为基础,分析了郯庐断裂北带地区的地壳-上地幔结构特征与不同地壳构造单元地震活动性之间的关系.结果表明:郯庐断裂北带两侧的壳幔结构存在明显差异,断裂带本身的发育与壳幔结构变异带关系密切;断裂的活动特点及分段明显受到地壳介质力学特性影响;郯庐断裂北带地区软流层的起伏与地貌形态呈明显的镜像关系,前者还制约着不同地壳构造单元的构造活动性及变形方式;郯庐断裂北带地区南、北两端地震较为活跃地段均与壳内低速 高导层发育地段相对应的事实,证明了刚性地块中壳幔结构较为复杂的活动断裂段是构成中强地震的主要控震构造. 相似文献
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