利用支持向量机和高斯过程回归测定水库诱发的地震(英文)

水库诱发地震震级(M)的预测是在地震工程中的一项重要任务。本文采用支持向量机(SVM)和高斯过程回归(GPR)模型根据水库的参数预测了水库诱发地震震级(M)。综合参数(E)和最大的水库深度(H)作为支持向量机和高斯过程回归模型的输入参数。我们给出一个方程确定水库诱发地震震级(M)。将本文开发的支持向量机和建立的高斯过程回归方法与人工神经网络(ANN)方法相比。结果表明,本文研发的支持向量机和高斯过程回归方法是预测水库诱发地震震级(M)的有效工具。     

超高阶次勒让德函数递推计算中的压缩因子和Horner求和技术

摘要：超高阶次（如2000阶次）缔合勒让德函数值的递推计算,在接近两极时达到极大的数量级（超过10的数千次方）,这导致现有递推方法在计算缔合勒让德函数值及其导数值时失效。我们通过插入压缩因子技术,提出一个修改的递推算法,并结合使用Horner求和技术计算球谐级数的部分和。试验表明,该算法至少可以计算到3600完全阶次的球谐级数式,优于现有结果。     

Preliminary study of lateral variation in crustal structure of Northeast China from teleseismic receiver functions

We conducted comprehensive receiver function analyses for a large amount of high-quality broadband teleseismic waveforms data recorded at 19 China National Digital Seismic Network (CNDSN) stations deployed in Northeast China.An advanced H-κ domain search method was adopted to accurately estimate the crustal thickness and vP/vS ratio.The crust has an average thickness of about 34.4 km.The thinnest crust occurs in the central region of Northeast China,while the thickest crust is beneath the Yanshan belt.The v...     

Morlet小波显著性检验和精度分析在地磁场和地震活动性周期分析中的应用

首先通过对加入随机噪声的合成信号进行Morlet小波变换并进行显著性检验, 分析所得信号的周期成分的显著性和非显著性, 然后研究信号周期长短、 信号观测时间段长短与精度之间的关系．在此基础上,以活动周期比较稳定的太阳黑子活动作为实例分析,结果显示本文的精度分析和显著性检验方法对于周期谱的精度和显著性研究是可行的．最后将该方法应用于全球地震活动周期谱的分析,求出全球地震活动周期谱及其显著性与精度．研究结果表明,在利用Morlet小波分析地磁场和地震活动性周期时引入显著性检验,并结合本文给出的精度, 可以从数据中提取出周期谱及其显著性和精度．      

Acidities of confined water in interlayer space of clay minerals

The acid chemistry of confined waters in smectite interlayers have been investigated with first principles molecular dynamics (FPMD) simulations. Aiming at a systematic picture, we establish the model systems to take account of the three possible controlling factors: layer charge densities (0 e, 0.5 e and 1.0 e per cell), layer charge locations (tetrahedral and octahedral) and interlayer counterions (Na⁺ and Mg²⁺). For all models, the interlayer structures are characterized in detail. Na⁺ and Mg²⁺ show significantly different hydration characteristics: Mg²⁺ forms a rigid octahedral hydration shell and resides around the midplane, whereas Na⁺ binds to a basal oxygen atom and forms a very flexible hydration shell, which consists of five waters on average and shows very fast water exchanges. The method of constraint is employed to enforce the water dissociation reactions and the thermodynamic integration approach is used to derive the free-energy values and the acidity constants. Based on the simulations, the following points have been gained. (1) The layer charge is found to be the direct origin of water acidity enhancement in smectites because the neutral pore almost does not have influences on water dissociations but all charged pores do. (2) With a moderate charge density of 0.5 e per cell, the interlayer water shows a pKa value around 11.5. While increasing layer charge density to 1.0 e, no obvious difference is found for the free water molecules. Since 1.0 e is at the upper limit of smectites’ layer charge, it is proposed that the calculated acidity of free water in octahedrally substituted Mg²⁺-smectite, 11.3, can be taken as the lower limit of acidities of free waters. (3) In octahedrally and tetrahedrally substituted models, the bound waters of Mg²⁺ show very low pKa values: 10.1 vs 10.4. This evidences that smectites can also promote the dissociations of the coordinated waters of metal cations. The comparison between the two Mg²⁺-smectites reveals that different layer charge locations do not lead to obvious differences for bound and free water acidities.     

Comparison of Results of Recent Seismic Profiles with Tectonic Models of the North China Craton

The geometry and timing of amalgamation of the North China craton(NCC) have been controversial,with three main models with significantly different interpretations of regional structure,geochronology,and geological relationships.The model of Zhao G C et al.suggests that the eastern and western blocks of the NCC formed separately in the Archean,and an active margin was developed on the eastern block between 2.5 and 1.85 Ga,when the two blocks collided above an east dipping subduc-tion zone.The model of Kusky ...     

基于BP神经网络的复合污染体系中沉积物吸附阿特拉津的规律

建立了Cu2+和阿特拉津(AT)复合污染体系中沉积物各活性组分及其交互作用对AT吸附量影响的BP神经网络模型,模型预测值和实验值的相关系数达到0.97,各集合的平均偏差均小于10%。模型显示,AT在沉积物上的主要吸附位是铁氧化物。沉积物吸附AT时铁氧化物、锰氧化物、有机质之间存在显著的交互作用,铁氧化物、锰氧化物交互作用贡献率为-130%～80%,铁氧化物、有机质交互作用贡献率为5%～28%,锰氧化物、有机质交互作用贡献率为-200%～-70%。各活性组分吸附AT的能力及其交互作用受Cu2+的影响较大,其中:Cu2+对AT在铁氧化物上的吸附表现为拮抗作用,对AT在锰氧化物上的吸附表现为协同作用,而对AT在有机质上的吸附影响不显著,同时Cu2+减弱了铁氧化物-锰氧化物和锰氧化物-有机质的交互作用影响,增强了铁氧化物-有机质的交互作用影响。     

滇东地区煤田构造格局与煤系赋存规律的研究

滇东地区位于特提斯和环太平洋构造体系的交接部位,煤田构造格局的总体特征是呈NNE向条带状展布。区内断层以NNE、NE向为主,受主要断裂影响,煤田在南北向呈带状,东西向呈段状展布,各煤矿区在平面上呈NE向带状分布。研究区煤系赋存受基底主干断裂的控制作用明显,变形强度由北向南逐渐增强,北部地区以褶皱构造为主,断层较少,煤层多保存于向斜构造中,保存较完整,煤层埋藏较深;南部受弥勒-师宗断裂带影响,断裂构造极为发育,对煤层破坏严重,煤系赋存不稳定。     

Effect of nitrogen to phosphorus ratios on cell proliferation in marine micro algae

The ratio of nitrogen/phosphorus (N/P) is known to affect cell proliferation of some marine micro algae. We evaluated the effect of N/P ratios on the proliferation and succession of phytoplankton using five marine micro algae species. We used two sources of nitrogen, NH4Cl (N1) and urea (N2), and a single source of phosphorous, NaH2PO4(P). The optimal N/P ratio that differed among the five species was affected by the source of nitrogen, being as follows (N1/P, N2/P in order): Thalassiosira sp. (30/1, 20/1),...