Physicochemical Environment during the Formation of the Mozumi Skarn-type Pb–Zn–Ag Deposit at the Kamioka Mine, Central Japan: A Thermochemical Study

Abstract: The physicochemical environment during the ore formation of the Mozumi skarn-type Pb–Zn–Ag deposit, Kamioka mine, Central Japan is discussed with silicate phase equilibria using calculated phase diagrams. The mineral assemblages, mineral chemistry, and fluid inclusion data are coupled with thermodynamic calculation to estimate the stability fO2–XCO2condition of the mineral assemblages at each ore formation stage. The skarn was approximated by the model system CaO–A12O3–FeO–SiO2–O2–CO2–H2O including grossular-andradite garnet and clinozoisite-epidote solid solutions. The solid solutions are combined into the calculation using "pseudocompound approximation", and real boundary of the mineral assemblages other than simple activity corrected diagram was provided. The diagrams also show isoplethal contour for garnet and epidote.     

Secular variations ing 1 0 component of geomagnetic field and its origin

The secular variations (SV) ing ₁ ⁰ of geomagnetic field, caused by the interaction between the geomagnetic field and the radial fluid-flow of the outer-core, are discussed with both statistical and analytic methods. When the value ofg ₁ ⁰ s ₂ ⁰ is relatively high compared with other terms, SV ing ₁ ⁰ is characterized by exponential change. When the effect of non-dipole field is notable, SV ing ₁ ⁰ shows complex features. Especially when the value of g ₁ ⁰ is close to zero, SV ing ₁ ⁰ is completely determined by the random process of non-dipole fields. Project supported by the National Natural Science Foundation of China (Grant No. 49429405) and by the Chinese Academy of Sciences.     

基于半参数回归的DDM内插方法

提出了一种基于半参数回归的数字水深模型(DDM)内插方法。将原始水深数据误差和内插函数的逼近误差分别视作数字水深模型的偶然误差和系统误差部分,构建DDM内插的半参数回归模型;基于距离法与L曲线法,分别确定正规化矩阵R与平滑因子α;采用按方位取点的加权平均法,估计内插函数在任意节点处的逼近误差。实验结果表明:所提方法提高了DDM的构建质量;海底地形复杂程度越大,所提方法对DDM构建质量的提高程度越大。     

An explicit approximation to the wavelength of nonlinear waves

An explicit and concise approximation to the wavelength in which the effect of nonlinearity is involved and presented in terms of wave height, wave period, water depth and gravitational acceleration. The present approximation is in a rational form of which Fenton and Mckee's (1990, Coastal Engng 14, 499–513) approximation is reserved in the numerator and the wave steepness is involved in the denominator. The rational form of this approximation can be converted to an alternative form of a power-series polynomial which indicates that the wavelength increases with wave height and decreases with water depth. If the determined coefficients in the present approximation are fixed, the approximating formula can provide a good agreement with the wavelengths numerically obtained by Rienecker and Fenton's (1981, J. Fluid Mech. 104, 119–137) Fourier series method, but has large deviations when waves of small amplitude are in deep water or all waves are in shallow water. The present approximation with variable coefficients can provide excellent predictions of the wavelengths for both long and short waves even, for high waves.     

大型稀疏正定法方法非零动态存储三角分解法

本文针对具有正定性质的大型稀疏法方法,提出了大型烯疏正定法方程的非零动态存储三角分解法,动用复式链表来动态存储稀疏矩阵。这种解法规律性强,简单直观,更易于计算机上实现,很好的解决了大型稀疏法方程所遇到的困难,极大提高了数据处理的效率。     

热带大气能量频散波射线的低频动力学特征

首先在非零频波条件下采用有、无辐散两类数学模型 ,讨论热带大气低频波传播动力特征 ,研究结果表明 ,非零频的波频率参数是热带大气低频振荡源能量频散波路径及其波振幅的关键影响因子 ,且热带地区低频振荡的经向传播与其伴随着的强对流云团有显著相关 ,并与热带低纬 β因子等相关。文中还进一步揭示了低纬大气低频振荡经向传播伴随的积云对流现象及向高中纬传播机理 ,描述了 WKB近似方法数学模型及其波射线方程解模态对大气低频动力特性及其水汽分布垂直结构、不稳定层结等因子的响应特征。     

基于GIS的任意发生元Voronoi图逼近方法

许多地理问题的空间分析中需要采用Voronoi图,但是目前我们尚缺乏一些简单的易于实现的构建任意发生元Voronoi图的方法,也缺乏一个能直接生成任意发生元Voronoi图的软件,为此我们提出了一种基于GIS的构建任意发生元的未加权Voronoi图的逼近方法。首先用有限点来逼近原始发生元,然后构建这些点发生元Voronoi图,最后消除那些属于同一发生元的顶点和边,即得到原始发生元的逼近的Voronoi图。在该算法的具体实现过程中,充分利用了现有GIS软件可以生成点发生元Voronoi图的特性和处理空间数据的能力。试验结果表明,这种方法可以生成未加权的任意形状发生元的逼近Voronoi图,能满足地理问题空间分析的需要。如地理客体可以是点状地理客体(城市、县城、交通枢纽、商业中心和金融中心等)、线状地理客体(交通运输线、经济地带和河系等)、面状地理客体(经济区、公园和绿地等)或者它们的组合,它们的空间影响范围或空间服务范围都可以采用Voronoi图来界定。     

稀疏天然植被对输沙量的影响

在内陆沙漠和海滨沙丘地区,均生长着不同类型低密度的天然植被,它对风沙流活动和风成地貌形态的形成与演变都具有一定的影响,但在大多数情况下是不足以防止风沙危害的。因此,为了达到防沙的要求,其中就存在着一个稀疏天然植被的有效临界密度问题。为此,通过对3个不同类型植物种、10组植株密度的风洞模拟研究表明,当平均输沙率减少到流沙表面的50%左右时,其相应的植物株密度为:呈紧密结构半球状植株密度为6株·m^-2;呈漏斗形上密下疏者为7株·m^-2和呈线状具有弯曲弹性的植株介于6~10株·m^-2之间。在各种植株密度的影响下,输沙率与有效起沙风呈正比关系,即q=a×(V_L-V_t)^b。     

长期GPS精密星历分析与轨道参数的函数逼近

以力学模型为基础,只能分析GPS卫星在短时间内的变化规律,而利用IGS提供的精密星历可以分析卫星在长时间段内的变化规律。基于精密星历研究了计算GPS卫星轨道参数的方法,然后对轨道参数在长时间段内的变化情况进行了分析,给出了分析的主要结果,并提出用正弦函数对轨道参数进行逼近,以得到GPS轨道的解析模型。