钛钡铬石,钛钾铬石的穆斯堡尔谱研究及晶体化学     

江嘉济  张建洪 《矿物学报》1990,10(4):370-375

本文在结构测定的基础上。应用穆斯堡尔谱技术。确定了钛钡铬石和钛钾铬石中铁离子的价态及结晶学位置。测试结果表明钛钾铬石中Fe的相对含量Fe~(2+)>Fe~(3+),而钛钡铬石中Fe~(2+)相似文献   

水生腐殖酸的可见—紫外光谱特征   总被引：6，自引：1，他引：6  

陶澍  崔军  张朝生 《地理学报》1990,(4)

本文研究了河、湖、海水腐殖酸和河流、湖泊沉积物腐殖酸的可见-紫外光谱特征,结果表明,水样腐殖酸与水体沉积物腐殖酸的可见-紫外吸收曲线显著不同,其差异不仅表现在以E240/E420为代表的紫外/可见吸收比上,也反映在以所有样品在不同波长的吸收值为原始变量进行聚类分析得到的结果中。三种水样腐殖酸中,河水与湖水腐殖酸的单位浓度紫外吸收值(以220nm为代表)十分接近,而海水腐殖酸的该值明显偏低。分别计算淡水和海水腐殖酸数据,则紫外吸收值与腐殖酸浓度之间有很好的线性关系。  相似文献   

含水团山砂岩破裂孕育过程中的Q值变化及声发射     

包一峰  许昭永 《地震研究》1990,13(4):396-401

本文采用滇西地震预报实验场基地团山砂岩浸泡一个月后进行真三轴压缩试验。结果发现:最小主应力轴方向和中间主应力轴方向Q值都有异常峰值,且变化不同。它们分别在破裂应力的40％—70％和50％—70％之间。而异常峰值后,又都在一段正常值,破后又都上升。从谱振幅随压力的变化看出,异常峰值的出现是由于高频成份的增加大于低频成份。峰值后的正常值出现是由于低频成份的增加及高频成份减小所致。而破后Q的上升则是由于低频振幅减小更多所致。声发射率也有峰值—相对平静——第二峰值—缓裂特征。  相似文献   

峨眉山玄武岩的辉石研究   总被引：1，自引：0，他引：1       下载免费PDF全文

黄开年 《地质科学》1988,(1):43-56

本文研究的峨眉山玄武岩的辉石均为单斜辉石。东川碱性火山岩中以透辉石为主,显示碱性岩系辉石的特征,但相对贫 LREE、Ti 等不相容元素,结晶时的 fO₂较高;攀枝花岩带主要是透辉石质普通辉石;其他剖面和地区多为普通辉石,且具拉斑质岩系富钙辉石的成分和演化特点。攀枝花带和西岩区辉石在化学成分上比较原始,而东岩区和中岩区辉石的成分演化程度相对较高。含 Ti 的“其他”阳离子对在各岩区（带）的辉石中均限重要,暗示它们的形成与火山弧环境无关。  相似文献   

Sea-bed characterisation and classification from the power spectra of side-scan sonar data     

Duncan Tamsett 《Marine Geophysical Researches》1993,15(1):43-64

This work is concerned with the automatic characterisation and classification of the sea-bed for side-scan sonar trace power-spectra.A parametric model of side-scan sonar trace power-spectra is developed from the equation for the magnitude frequency response of a Butterworth filter. The model's parameters are optimised to give a least squares fit with observed spectra. Three of the optimised parameters are used to define features.  相似文献   

On the estimation of surface gravity waves from subsurface pressure records for estuarine basins     

C.Ernest Knowles 《Estuarine, Coastal and Shelf Science》1983,17(4):395-404

According to small-amplitude theory, the surface gravity-wave spectrum can be estimated from a subsurface pressure-fluctuation spectrum by applying a factor (K) that compensates for the attenuation of surface-wave amplitude as the depth below the water surface and the wave frequency increase.There are a number of factors, however, that cause K to be inaccurate over a large portion of the spectrum's frequency range. Numerous attempts have been made to derive an empirical correction factor (n) that could be applied to K to provide a better estimate of the surface-wave spectrum. This paper evaluates some of these empirical factors, specifically for use in an estuarine environment, and recommends Graces' (1978) equation for n as a function of the non-dimensional frequency parameter kh (where $\text{k =}\text{2π}\text{L}$ is the local wavenumber, h the local depth and L the wavelength).The paper also evaluates the maximum limit (K_max) on the magnitude of K suggested by Esteva & Harris (1970), where relative depth $\text{d}\text{h}$ (d is the pressure transducer height above the bottom) and k_oh (a parameter directly related for large values of kh to wave frequency by the dispersion relation) are the independent variables. The choice of K_max may be made unimportant if d is selected beforehand using an equation (Knowles, 1981a) for the minimum $\text{d}\text{h}$ limit affected by the choice of K_max.  相似文献   

Question of the pitch-roll buoy response to ocean waves as a simple harmonic oscillator?     

K. E. Steele  D. W. Wang 《Ocean Engineering》2004,31(17-18):2121-2138

The assumption that the East and North deck slopes of a pitch–roll buoy respond to East and North sea slopes as simple harmonic oscillators is routinely made by the National Data Buoy Center (NDBC) and others producing directional wave data. Although directional wave data derived with this assumption usually appear to be of good quality, the validity of the assumption has not previously been more directly demonstrated. In this paper, a method is proposed to judge the validity of the assumption for any set of time series records of buoy angular motion. The proposed method is applied to 200 record sets taken by an NDBC buoy located at ocean station 46024, and to five record sets taken by another NDBC buoy at 46051. For the 46024 data, it was demonstrated that the simple harmonic oscillator assumption was near perfectly valid. For the smaller 46051 data set, the simple harmonic oscillator assumption was shown to be slightly less valid.  相似文献   

扇贝碱性磷酸酶中Zn的作用     

欧阳培  徐培宁  李碧荣 《热带海洋学报》1991,(2)

以华贵栉孔扇贝Chlamys nobilis(Reeve)为材料,获得聚丙烯酰胺凝胶电泳为单一蛋白区带的酶制剂。用凝胶过滤法测得该酶的分子量为159000,由20种氨基酸组成,共1118个氨基酸残基。每个酶蛋白含有4个Zn原子。将该酶的酶制剂制成脱Zn酶后,与相同浓度过度性两价金属离子作用,其活力回升以Zn最强,Co次之。若向脱Zn酶蛋白分别加入一定量Zn原子或Co原子,根据实验结果初步推测:每个酶蛋白的4个Zn原子中有2个Zn原子先与该酶结合,与酶的催化作用有密切关系;另外2个Zn原子与酶结合,则起维持酶结构的作用,与哺乳动物和Eschericha coli来源的碱性磷酸酶研究结果一致。此外,本实验采用可见吸收光谱和圆二色谱(CD)来确证Co能很好地取代该酶蛋白内的Zn,与Simpon报道相比较,得知当Co原子加入脱Zn酶时,先加2个Co~(2 )离子结合到该酶的结构部位,而后加2个Co~(2 )离子才结合到催化部位。  相似文献   

Second-Order Analytic Solutions of Nonlinear Interactions of Edge Waves on A Plane Sloping Bottom     

洪广文  张俞 《中国海洋工程》2010,24(1)

Based on the full water-wave equation,a second-order analytic solution for nonlinear interaction of short edge waves on a plane sloping bottom is presented in this paper.For special case of slope angle β=π/2,this solution can reduced to the same order solution of deep water gravity surface waves traveling along parallel coastline.Interactions between two edge waves including progressive,standing and partially reflected standing waves are also discussed.The unified analytic expressions with transfer functions for kinematic-dynamic elements of edge waves are also given.The random model of the unified wave motion processes for linear and nonlinear irregular edge waves is formulated,and the corresponding theoretical autocorrelation and spectral density functions of the first and the second orders are derived.The boundary conditions for the determination of the parameters of short edge wave are suggested,that may be seen as one special simple edge wave excitation mechanism and an extension to the sea wave refraction theory.Finally some computation results are demonstrated.  相似文献   

Damping modification factors for SDOF systems subjected to near‐fault,far‐fault and artificial earthquakes     

George D. Hatzigeorgiou 《地震工程与结构动力学》2010,39(11):1239-1258

Damping modification factors (DMF) are used in modern seismic codes to adjust elastic response spectral values corresponding to 5% of viscous damping to other higher or lower damping levels. This paper presents a simple and effective procedure to estimate DMF for single‐degree‐of‐freedom systems. Empirical expressions are proposed for displacement, velocity and acceleration response spectra, where four types of soil conditions, from hard rock to soft soil are considered. This study also examines, for the first time, the influence of artificial earthquakes on DMF. Furthermore, natural near‐fault and far‐fault seismic ground motions are considered where it is testified that the fault distance has no impact on DMF. Finally, it confirms that, in contrast to the considerations of many seismic codes, DMF are strongly dependent on the period of structural vibration while there are significant problems of using the same modification factor to estimate maximum displacement, velocity and seismic forces. Copyright © 2010 John Wiley & Sons, Ltd.  相似文献