一种新ⅡR分数阶微分滤波器

从频域角度出发,分析了几种基于典型微分算子的ⅡR分数阶微分滤波器的数字实现,提出一种频率响应更接近理想微分的新算子,在此基础上运用连续分数扩充方法实现了分数阶微分滤波器的设计,并详细推导基于新算子的ⅡR分数阶微分滤波器的数字实现。实验证明,基于新算子的ⅡR分数阶微分滤波器频率响应整体上优于Tustin和Simpson等其他ⅡR分数阶滤波器。     

Fractional order model for granular soils under drained cyclic loading

The theory of fractional calculus has been successfully applied to model the triaxial behaviour of soils under static loading conditions. However, limited work has been carried out in using the fractional calculus to describe the cyclic behaviour of granular soils. In this paper, a fractional order constitutive model for granular soils under drained cyclic loading is proposed by incorporating the concept of fractional rate for strain accumulation. The fractional rate for strain accumulation is obtained from the analysis of the experimental data by utilizing the fractional calculus. Comparison between the test results and model predictions is presented. The key feature of the proposed model is that it can reasonably characterise the cyclic deformation of granular soils under both low and high loading cycles. Copyright © 2016 John Wiley & Sons, Ltd.     

A FIC‐based stabilized mixed finite element method with equal order interpolation for solid–pore fluid interaction problems

A new mixed displacement‐pressure element for solving solid–pore fluid interaction problems is presented. In the resulting coupled system of equations, the balance of momentum equation remains unaltered, while the mass balance equation for the pore fluid is stabilized with the inclusion of higher‐order terms multiplied by arbitrary dimensions in space, following the finite calculus (FIC) procedure. The stabilized FIC‐FEM formulation can be applied to any kind of interpolation for the displacements and the pressure, but in this work, we have used linear elements of equal order interpolation for both set of unknowns. Examples in 2D and 3D are presented to illustrate the accuracy of the stabilized formulation for solid–pore fluid interaction problems. Copyright © 2016 John Wiley & Sons, Ltd.     

电子探针微量元素分析的一些思考

电子探针分析具有快速、无损、微区、原位、高精度、高准确度、高分辨率,高灵敏度的技术特征,是现代科学发展研究中非常重要的技术手段。电子探针定量分析结果反映的是物质中原子的个数信息（摩尔含量）,而非原子的“ 重量”或“ 质量”,因此判断数据的合法性及准确度的重要依据应该体现在原子比值上,而非简单的总量值是否在100±2 wt% 范围。物质（矿物）中的微量元素含量大都具有标型意义,能够反映出重要的（地质）成因环境,是物质科学重要的研究分析对象。电子探针分析具有的技术特征是进行（原位）测试微量元素的最佳手段。然而在实际工作中,微量元素的测试往往面临着若干技术上的困难和一些不可回避的缺点,尤其是在采用波谱仪进行定量分析的时候,测量的精度、准确度、可靠性、以及可重复性都需要进行专业的、细致的、全方位的实验条件设置考量,同时进行大量的条件实验来验证。一般来说,除了可以简单地通过增加激发能量（加速电压、束流强度）和延长测量时间来获得较高的检测极限和较低的标准偏差外,还需要注意至少四个方面的内容：（1）波谱仪中分光晶体的选择;（2）元素特征峰峰位重叠的识别与背景值的影响;（3）探测器中PHA 滤波功能的启用;以及（4）标准物质的正确选择和标定。在数据合法性与客观性研判上,面临最小测试样本数量的问题,可以引入统计学中的迭代计算方法来进行评估,对均质样品中某微量元素的平均含量问题给予比较客观的判断。     

基于FPGA的数字多道脉冲幅度分析器设计

数字化多道脉冲幅度分析成为多道分析技术的主流,介绍了一种基于单FPGA芯片的数字脉冲幅度分析器的设计。采用EP3C40Q240作为数字核信号处理器,将ADC采集到的核信号进行数字积分、寻峰、阈值检测等数字处理,并得到能谱。系统通过高速RS485接口实现数字多道与上位机能谱分析软件的通信。最后给出了由NaI(Tl)探测器得到的核信号经数字多道处理后获得的137Cs能谱图。     

Uncertainty relation in viscous hydrodynamics and its effects in collective flow observables

The uncertainty relation is considered to be one of key features of quantum mechanics which distinguishes quantum and classical systems. Recently, we developed a new formulation of the uncertainty relation based on the generalized scheme of variational principle, the stochastic variational method (SVM). In this method, the uncertainty relation is related to the nondifferentiability of observables and thus can be obtained even in classical stochastic systems. This new formulation resolves the famous paradox in quantum mechanics, the angular uncertainty relation without introducing artificial assumptions. In this paper, we show that the fluctuations of position and momentum for a nonrelativistic viscous fluid element satisfies the uncertainty relation analogous to the corresponding quantum mechanical one. Such a fluctuation is sensitive to the temperature gradient at the freezeout surface and can affect the collective flow anisotropy in relativistic heavy-ion collisions.     

CT对肝内胆管结石合伴肝脓肿的研究

目的是研究肝内胆管结石合伴肝脓肿的CT表现及临床特点,并探讨肝内胆管结石合伴肝脓肿发病的因果关系,为临床治疗提供重要依据.     

宇宙分维构造及其数学基础

探讨了宇宙分维构造的形式,给出了分维微积分及分形测度的数学基础,包括分维导数及分维微积分的表述形式、分维微分方程的规整空间积分解、分形测度的分维微积分定义及自相似分形的测度计算方程．作为诠释,探讨了原子核内中子与质子的趋势关系方程,以及其周期解和原子序数极限值。     

基于知识标注的地理信息语义服务框架研究

基于空间语义学基础理论,将传统的地理信息服务技术与新兴的语义服务技术相结合,建立地理信息语义服务框架及知识标注方法体系,并应用于地理空间信息服务处理中,提供智能化、自动化的地理信息服务发现、组合与触发策略;设计基于文本挖掘算法的半自动知识标注引擎,提高服务处理自动化程度,实现包含丰富语义信息的地理空间语义服务的发布;建立基于规则和推理引擎的地理信息服务匹配与发现机制,提高服务发现效率;建立地理信息服务语义标注与服务匹配评价方法,采用基于空间关联规则的标注正确性评估策略,验证知识标注价值。     

-89G634.41H130;F085;17;46;F;H;F085_17;H130

试评价是英语新课程的重要组成部分,是实现新课程标准的重要保证。作为评价的试卷应该难度适中,充分体现教育、教学目标,并能对教学产生最大的正面导向作用,从而真正体现受测试者的英语水平和能力,准确反映教学情况和教学效果。在此问题上,命题者要从命题的方向、内容、原则与方法等几个方面去研究和把握。0山东师范大学外国语学院学报(基础英语教育)Journal of Basic English Education94-97G634.41H130;F085;17;46;F;H;