Development of the constraint equation method with theoretical coefficients in X-ray fluorescent analysis

Questions on increasing the accuracy and expanding the application field of calibration equations with calculated theoretical coefficients used in X-ray spectral analysis are discussed. We consider basic versions of the classical method of theoretical corrections [1] and their further development based on the use of intensity ratios of analytical lines as the analytical signal and also the use of absorption factors as theoretical coefficients. The methodic approaches developed are tested on a spectrometer of the SPECTROSCAN MAX series by the example of analysis of alloy steels.     

叠层板型燃料堆芯元件模型的流固耦合振动

叠层板状结构是新型核反应堆设计中所采用的一种堆芯元件，具有结构合理、比功率高和传热性能好等显著特点。提出了单梁与多梁对接的力学模型，以干模态振型函数序列作为试函数对复模态振型方程进行变分求解，研究了叠层板状元件在湿模态下的固有频率与振型，发现叠层板状结构的流致振动具有复模态特性，文中初步找到一些规律性的结果，为设计和安全分析提供一些有用的方法和数据。     

刚柔耦合包装系统动态特性分析的逆子结构方法

目的以三级刚柔耦合包装系统为研究对象,推导由系统水平传递函数反向预测部件水平传递函数的逆向子结构分析公式。方法结合刚性和柔性系统特点,分别将三级刚柔耦合系统转化为二级刚性和二级柔性结构,经过理论推导得出结果,并用集总参数模型进行验证,对理论公式进行误差分析。结果验证了理论公式的正确性,获得了各测量传函对预测传函的影响规律。结论为刚柔耦合包装系统动态力学分析提供了理论依据。     

Diffraction efficiency analysis of a parallel-aligned nematic-liquid-crystal spatial light modulator

An optically addressed parallel-aligned nematic-liquid-crystal spatial light modulator is developed for applications in optical information processing and interferometry. Its performance, including diffraction efficiency, is measured, and a theoretical analysis of diffraction efficiency is performed. A comparison between the experimental results and the theoretical analysis shows good agreement. The diffraction efficiency of near-sinusoidal gratings written on the device is of the order of 30%, which is close to theoretical maximum.     

Fatigue analysis of offshore platforms subject to sea wave loadings

The fatigue damage calculation for random loading on offshore platforms takes the form of a rainflow analysis of the dynamic response of individual members to various sea states. This procedure is lengthu and consequently this paper attempts to provide a theoretical method for determining random load fatigue damage. This dynamic response for many joints leads to a broad band random loading but despite this, previous theoretical methods have simplified the loading to narrow band. This has not been done in the present case; instead, an analysis based on broad band random loading has been produced. This theoretical approach gives a fatigue life estimate which is slightly (6.6%) more conservative, for a typical example, than a rainflow analysis.     

木托盘受力性能理论分析及有限元模拟

目的对木托盘静载堆码时的力学性能进行理论分析和有限元模拟。方法建立木托盘顶铺板和纵梁板的力学模型,通过理论计算获得选用松木和杨木LVL 2种不同材料时的最大应力和最大挠度;按国家标准建立木托盘有限元模型,进行网格划分、施加载荷和约束后,获得选用松木和杨木LVL 2种不同材料时的最大等效应力值和最大变形量,并与理论分析结果进行对比。结果理论分析和有限元分析结果规律一致,最大应力均出现在中间纵梁板上,最大变形均发生在顶铺板上,且数值差距较小,2种分析方法均合理可行。结论该研究为木托盘的性能分析提供了有效的方法。     

A theoretical analysis for oxidation of titanium carbide

The oxidation kinetics of titanium carbide (TiC) powder has been studied based on the experimental data summarized as well as theoretical analysis in terms of our model. The effects of temperature, especially the oxygen partial pressure on the oxidation kinetics, are discussed not only qualitatively but also quantitatively in the light of our special theoretical approach. The calculated results show that our theoretical analysis is reasonable.     

离心力场中电动振动台的建模

本文用多刚体分析的方法建立了在复合振动环境试验中离心机上电动振动台的数学模型,推导出了理论解,并对其进行了全面的仿真分析,仿真结果验证了理论解的正确性,从而为控制系统的设计提供了依据     

神经心理学下的潜意识交互设计方法

目的探析在神经心理学为指导理论下的潜意识与交互设计结合所能产出的设计方法。方法通过对原有的潜意识理论指导下的设计方法的研究,得出潜意识理论与设计学科结合的理论和实践意义。通过对交互设计和神经心理学下的潜意识理论研究,得出该理论与交互设计结合的可能性及应用方向,通过对神经心理学的理论研究和对现有案例的分析,得出应用新潜意识理论的设计方法。结论在理论研究和案例解读的基础上,提出了神经心理学下的潜意识交互设计的两个方法,即习惯导向式设计和预期对话式设计。     

Investigation of current distribution conditions in multiwire superconducting cables under the influence of self-magnetic field

The current distribution in a multi-wire round cable subjected to self-magnetic field is considered in this paper. A theoretical analysis of the current distribution process was made. The influence of layer parameters on the current distribution between the layers was determined. The theoretical analysis showed that it was necessary to twist two external layers into different directions with a minimum pitch to increase the current in the internal layers. It was shown that manufacturing round cable with more than two superconducting layers was unnecessary. Formulae are given allowing determination of the current in all layers. The theoretical conclusions were confirmed by the experimental results.     

Strain Measurement on Composites: Errors due to Rosette Misalignment

Abstract: Electrical resistance strain gauges are increasingly used for the determination of the strain field in composite components. The effect of the angular misalignment of a strain gauge rosette on the determination of the strains in a composite material is investigated in this paper. The theoretical analysis shows that the strain error along the principal material directions depends on the difference of principal strains, on the angular misalignment of the rosette and on the angle between the maximum principal strain and the fibre direction. The paper also shows experimental evidence for the theoretical analysis.     

On the Buckling Response of Offshore Pipelines under Combined Tension,Bending, and External Pressure

In this paper, the buckling and collapse analysis of offshore pipeline under combined tension, bending moment, and external pressure has been presented with theoretical analysis and FE (finite element) simulation method respectively. Based on the model initially proposed by Kyriakides, a 2-D theoretical model has been further developed. To verify the correctness and accuracy of the model proposed in this paper, numerical simulations have been conducted with 3-D FE model using ABAQUS software. Good consistency has been shown between the calculation results which validate the availability of the theoretical analysis. On this basis, the influence of load path, material properties, and diameter-to-thickness ratio on the buckling behaviors of the pipes have been discussed. Based upon the discussion mentioned above, some significant conclusions have been drawn.     

Dynamic response of a grillage under mass impact

An approximate theoretical analysis is presented in this paper for the dynamic plastic response of a clamped beam grillage when struck transversely by a mass at the centre which produces large transverse displacements. The theoretical rigid-plastic predictions are compared with some recent experimental results on grillages struck by large masses and the predictions of a quasi-static method of analysis. The influence of inertia is explored for the behaviour of a grillage when struck by a small striker travelling with a high velocity.     

旋转超声内圆磨削砂轮变幅器的设计与试验研究

砂轮变幅器是旋转超声内圆磨削谐振系统的关键部件,其设计质量直接影响超声磨削的工艺效果。但目前内圆磨削砂轮变幅器缺乏较为完善的理论分析模型。为提高砂轮变幅器理论分析模型的通用性,基于非谐振设计理论建立了纵向谐振砂轮变幅器的理论分析模型,并利用砂轮变幅器各振动单元间的力、位移连续条件与边界条件推导了其频率方程。然后,针对频率方程进行编程求解,并通过ANSYS有限元仿真分析进行验证。最后,加工制作了纵向谐振砂轮变幅器,并开展阻抗特性分析试验、超声谐振试验和振动位移测量试验,分析了其谐振特性。试验结果表明,所研制的砂轮变幅器的谐振试验频率与理论设计频率一致,其输出端振动位移的试验值与仿真值的相对误差为7.83%,符合旋转超声内圆磨削的要求,验证了理论分析模型求解的正确性。研究结果为旋转超声内圆磨削砂轮变幅器的设计提供了便捷且有效的方法。     

半导体制冷最优工况的理论分析与实验研究

传统极限工况有最大制冷量工况和最大制冷系数工况,在此其间,必存在一特殊工况,使得既具有较大的制冷量,又具有较小的功耗,此工况即为“最优工况”。本文首先对半导体最优工况进行了理论分析,推导出最优电流的理论公式;再对一小型半导体制冷箱进行实验,通过调节电流改变工况,分析了8种工况实验下的性能参数变化情况,对实验数据进行回归分析,得出回归方程,从而找出最优电流对应的最优工况。在此工况下进行工作,即可获得较大的制冷量,又可消耗较小的功率,从而提高了半导体制冷器的制冷性能。实验结果与理论分析结果基本吻合。     

Stress–strain curve for concrete in circular columns based on elastoplastic analysis

This paper presents a stress–strain curve that describes the axial behavior of concrete in circular columns with lateral reinforcement. As opposed to most studies on this subject, which used semiempirical methods, the proposed stress–strain relations are based on a theoretical derivation. They have been derived from analysis of the problem’s full range according to the theories of elasticity and plasticity. Based on these theories, the current study analytically examines the influence of the main variables, such as the volumetric lateral reinforcement ratio and the material properties, on the behavior of circular confined concrete columns and proposes theoretical expressions that describe their stress–strain relations. Application of the proposed curve shows good agreement with published test results. Since these expressions were derived from a theoretical analysis, they can be considered as an analytical verification of existing empirical curves, yet they are also simple enough for practical applications.     

石墨烯谐振特性研究进展

石墨烯具有优异的谐振特性, 相关研究对谐振式传感器的未来发展和应用具有重要意义。目前石墨烯谐振特性的研究方法主要包括实验测量方法和理论分析方法, 后者又分为基于纳米力学的分析方法和基于经典力学的分析方法。由于利用实验精确获取石墨烯的谐振特性比较困难, 相关的理论研究和总结十分重要。本文就石墨烯谐振特性的研究进展进行综述, 包括谐振式石墨烯传感器的实验和理论分析方法的分类、现状、优缺点以及发展趋势等。     

制动振动噪声研究的回顾、发展与评述

由于制动振动噪声问题的重要性和复杂性,许多研究者对此问题从各方面进行了研究。以近期的研究工作为重点对制动振动噪声的研究工作进行了较为系统的回顾。重点阐述了各种制动噪声机理研究以及对制动噪声的理论建模和分析工作;对各种机理解释、理论分析方法及其他相关问题进行了分析和评述;最后,进行了总结并对未来的研究工作提出了一些展望与建议。     

钢框架极限承载力的有限变形理论分析和试验研究

本文为钢框架极限承载力的全过程分析提供了一种有效的方法。该法基于非线性连续介质力学理论,导出了结构的几何刚度矩阵,它不仅包含了轴力对结构刚度的影响,而且还包含了剪力和弯矩的影响。根据内力屈服面塑性流动理论,把经典的塑性铰概念加以推广,既考虑了塑铰性处内力之间的相互影响,也考虑了弹性卸载的影响。进行了四榀钢框架极限承载力的试验,试验与理论分析结果符合良好。     

一种修正的基于混沌预测误差的目标检测算法

基于混沌预测误差的目标检测算法是检测混沌背景下目标的算法.本文对该算法的检测结果进行了分析,分析结果表明其检测到的目标区域比实际的目标区域大.针对这个问题,对基于混沌预测误差的目标检测结果进行了修正,修正后的结果更接近于目标的真实大小.用Lorenz混沌系统产生的仿真数据和实测的机载海面合成孔径雷达(Synthetic Aperture Radar,SAR)图像进行了实验.实验结果与理论分析的结果一致,从而证明了理论分析的正确性.