Energy flux characteristics of seismic waves at the interface between soil layers with different saturations

Based on the multiphase poroelasticity theory describing the propagation of waves in the unsaturated fluid-saturated porous medium, the reflection and transmission coefficients of the seismic waves at the interface between soil layers with different saturations are obtained. Our unsaturated model consists of a deformable skeleton in which two compressible and viscous fluids (i.e., water and gas) flow in the interstices. Three compressional waves (i.e., P1, P2, and P3 waves) and one shear (i.e., S wave) wave exist in the unsaturated soils. The expressions for the energy ratios of the various reflected and transmitted waves at the interface during the transmission and reflection processes are presented in explicit forms accordingly. At last, numerical computations are performed and the results obtained are respectively depicted graphically. The variation of the energy ratios with the incident angle, wave frequency and saturation degrees of the upper and lower soil layers is illustrated in detail. The calculation results show that the allocation of incident seismic waves at the interface is influenced not only by the angle and frequency of the incident seismic waves, but also by the saturations of the upper and lower soil layers. It is also verified that, at the interface, the sum of energy ratios of the reflected and transmitted waves is approximately equal to unity as was expected. This study is of importance to several fields such as geotechnical engineering, seismology, and geophysics.     

Influence of sugar filter mud on formation of portland cement clinker

To explore the mechanisms of filter mud (FM) in the portland cement clinker formation, and to make effective use of FM in the cement production as lime-based raw materials, the influences of FM on the apparent activation energy of calcium carbonate decomposition, liquid phase amount, crystalline phase and tricalcium silicate polymorphism were investigated by TA, SEM and XRD. The experimental results show that FM can reduce apparent activation energy of calcium carbonate decomposition, and increase liquid phase amount. Appropriate FM replacement ratios are useful to promoting the C₃S formation and heightening the C₃S content. New phases of α-C₂S and C₂S·0.5Ca₃ (PO₄)₂ can be found in the clinkers while the ratios are above 15%. In addition, impurities in FM can induce the C₃S polymorph to transform.     

The influence of oleic acid on the hydration and mechanical properties of portland cement

To investigate the effects of OA on the portland cement using oleic acid （OA） as grinding aid and the effects of OA on the portland cement, we characterized the different perfermances of the cement, discussed the characteristics of properties. The results reveal that the OA can reduce the water requirement of normal consistency. With the content of OA added, setting time was extended. The OA can significantly improve the rheological properties of cement-based materials, while the compressive strength decreases.     

The oxidation state of sulfur detected in Na2O-CaO-SiO2 float glass by X-ray absorption near edge structure spectra

The oxidation state of sulfur is detected in Na2O-CaO-SiO2 float glass by synchrotron radiation X-ray absorption near edge structure (XANES) spectra at the sulfur K edge. The measured spectra show the only presence of S6+ in the Na2O-CaO-SiO2 float glass and the oxidation state of sulfur do not change with the increase of glass depth. It is also found that, after the melt has gone through the molten tin bath, the S6+ is the dominant species, but S2- is also present on both surfaces. It is not certain whether cation bonds to S2- or not, because there are many cations dissolved in the melted tin which makes the spectrum complicated.     

Model study of IPMC beam electroactive response based on root deformation

Ionic polymer-metal composite (IPMC) is a type of electroactive polymer (EAP). In this paper, based on Nemat-Nasser model, an improved model is developed to explain the initial nonlinear response of electric actuation on the fixed end deformation. Three IPMC strip samples with different surface resistance are chosen for analysis. Further, from simulation and experiment results, it is found that the root deformation made the tip movement of the IPMC strip with little surface resistance, but this effect was less and less when the surface resistance reduced. The calculation results of this model for the fixed end show a more accurate simulation for the actual deformation of IPMC strips.     

基于物联网与3G整合的电子商务应用资金流探析

文章在简要介绍物联网与3G网络的基础上,阐述了物联网与3G整合背景下电子商务资金流所具备的特点,进而论述了此背景下资金流的优化和作用,最后重点分析了整合背景下电子商务资金流的两个应用案例。     

砂土的剪胀方程及其塑性势(Ⅰ):发展现状

以能量守恒原理为主线,在各向同性前提下,对Taylor剪胀方程、Cam-clay剪胀方程、修正Cam-clay剪胀方程、Rowe剪胀方程和扩展的Rowe剪胀方程等进行了较全面的综述.论证了剪胀方程和塑性势函数之间的相互转化关系.指出了Lade-Kim塑性势函数和Nova塑性势函数的缺陷之处,即这两个塑性势函数均没有合理耦合临界状态这一概念.     

高校辅导员队伍专业化建设的实践

高校辅导员是大学生思想政治教育的一线工作者。从生态学和心理学视角切入,以校本培训理念和发展性理念为基础,从辅导员职责体系构建、辅导员培训体系构建以及辅导员专业化保障体系构建等层面,探索高校辅导员队伍专业化建设的路径。     

基于小包规律分析的BT流量识别技术

为提高在采样环境中Bernaille等的早识别技术对BT(BitTorrent)流量识别的准确性,通过分析BT协议和BT实际传输数据,找出其中BT传输过程前期有效载荷低于70个字节的小包出现的规律,并以此为基础来识别BT流量。实验表明,对比早识别技术,该方法能够提高在采样环境中识别的准确性,克服了早识别技术对BT流中前几个数据包的依赖的不足。     

中文问句分类特征的研究

针对"不同的问句分类特征对问句分类的影响不相同,提取和处理这些特征的时间复杂度也不相同"的问题,提取问题疑问词、核心关键词(疑问词的一二级依存词和问句中心语)的主要义原、核心关键词的首义原、问句主谓宾的主要义原、命名实体、名词单(复)数等六种分类特征,采用支持向量机分类算法,对事实疑问句进行不同特征组合的分类对比实验,发现采用词义消岐技术提取的主要义原不仅对分类的准确率影响明显,而且大幅降低特征向量的维数,减少了处理时间。