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.     

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.     

叶片厚度仪原理误差的研究

建立了叶片厚度仪的实际传动特性方程,通过与理论的线性模型比较,获得了仪器的原理误差函数式。并且分析了测量时接触变形误差对测量结果的影响问题,在此基础上提出了减小原理误差的方案,并以增加测量臂长为例论述了减小原理误差的方法.     

Ultra strong polymer fibers: Ab initio calculations on polyethylene

The Car-Parrinello technique is used to study the electronic structure of orthorhombic polyethylene as well as the elastic modulus. The theoretical band structure and density of states are in very good agreement with experiments. The best experimentally realized elastic modulus is better than 86% of the presented theoretical value.     

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。     

Calculations of theoretical strength: State of the art and history

Current state and historical evolution of theoretical strength calculations is presented as a brief overview completed by a database of selected theoretical and experimental results. Principles of a sophisticated analysis of mechanical stability of crystals are elucidated by means of a schematic example. Stability conditions and Jacobian matrixes are presented for selected crystalline symmetries and deformation paths. The importance of this analysis for understanding micromechanics of fracture is shown against the background of the influence of crystal defects. Differences between theoretical and experimental theoretical strength (TS) values are discussed and some challenging tasks are outlined for the near future.     

拉压不同模量的缝合三明治夹芯结构梁弯曲性能

为了建立具有不同拉伸和压缩弹性模量的缝合三明治夹芯结构梁的中性层位置和弯曲刚度的理论预测方法,并进行相关试验验证。首先,将缝合三明治夹芯结构梁看成准层状结构,考虑其拉压不同模量及材料上下面板几何尺寸不同的特点,基于修正的Reissner层板理论,建立了弯曲刚度和中性层位置的理论预测方法;其次,开展了缝合三明治夹芯结构梁的三点弯曲试验,并采用数字图像相关(DIC)法测试了中性层位置;最后,对弯曲刚度和中性层位置进行了理论预测。结果表明:理论预测值与试验结果吻合较好,证明了该理论预测方法的有效性。     

Analysis of the influence of the two types of the journal articles; theoretical and empirical on the impact factor of a journal

The study discusses the necessity to analyze the influence of theoretical and empirical types of journal articles on the citation impact of Spanish psychology journals. Three of the most representative Spanish psychology journals were selected for the purposes of this study: Papeles del Psicólogo, Análisis y Modificación de Conducta and Psicothema. Twenty-three psychology journals in Spanish were used as source journals. Altogether, there were sixty-seven issues reviewed for the references and ninety-three issues for the articles. The bibliometricanalysis was conducted by six highly trained psychologists. The results demonstrated differences regarding the percentages of empirical and theoretical articles published in the three examined journals and the number of citations received by them based on the article type. When normalizing the results according to the number of theoretical and empirical articles that were published, it becomes evident that the theoretical articles receive on average twice as many references as the empirical ones. We discuss the importance of this effect on the comparison of journals based on their citation impact and show the evidence that it is only valid to compare journals which publish a similar percentage of theoretical and empirical articles.     

Collaboration patterns in theoretical population genetics

The paper points out that the characteristic properties of general social networks are reflected in co-authorship patterns of theoretical population genetics as studied from 1900 to 1980. The results are consistent with the analyses of bibliographies where the co-authorship networks in invisible colleges probably have shown the same behavioural patterns as the non-scientific populations. The patterns of behaviour are portrayed in two-dimensional as well as three-dimensional representations of co-authorship data in theoretical population genetics.     

The significance of theoretical concepts in activity theory for applied research in aviation

This paper considers theoretical issues in Activity Theory (AT) as applied to pilot performance, with a focus on the inter-relationship of theoretical and applied research in psychology. This paper will discuss the significance of theoretical psychological research for the resolution of applied problems using the examples in aviation. Special attention will be given to the spatial orientation of the pilot during flight in non-standard and accidental conditions.     

A poroelastic bone model for internal remodeling

In this paper a theoretical analysis of the internal bone remodeling process induced by a medullary pin is presented. Bone is treated as a poroelastic material using Biot's formulation. Based on the theory of small-strain adaptive elasticity, a new theoretical approach for internal remodeling is proposed. Our results show that the rate of internal remodeling decreases as the porosity of the bone increases.     

Einstein制冷系统气泡泵理论模型修正验证研究

基于漂移流模型理论建立了气泡泵理论模型,对Einstein制冷系统中气泡泵在绝热弹状流下的提升特性进行理论分析,并以饱和纯水为工质对气泡泵稳态性能进行实验研究。根据气泡泵性能参数的实验值和理论计算值,采用最小二乘法对气泡泵阻力损失系数进行拟合,对气泡泵理论模型进行修正并得到相应的实验关联式,并对该关联式的可信度进行验证。结果表明：实验结果与理论修正结果吻合性较好,误差在5.3%以内,修正结果具有较强准确性和可行性,完善了气泡泵理论模型。为气泡泵的优化设计提供理论指导,对进一步研究Einstein制冷系统气泡泵性能具有重要参考价值。     

Proximity Effect From an Andreev Perspective

The current understanding of the superconducting proximity effect is reviewed taking into account recent experimental and theoretical results obtained for mesoscopic normal metal-superconductor junctions as well as superconducting weak links. Although known for 40 years the phenomenon remained poorly understood. Current insights are the result of theoretical developments leading to the nonequilibrium quasiclassical theory, getting experimental access to proximity structures on a submicron scale as well as by combining it with the knowledge developed in the 80s on quantum transport in disordered and ballistic systems.     

环形调频液体阻尼器（TLD）的计算模型

本文建立了液体在刚性环形容器内晃动的计算模型，这一模型可以用于调频液体阻尼器（ＴＬＤ）及结构─ＴＬＤ相互作用的研究。为了验证计算模型，进行了一系列的振动台试验，研究液体晃动第一振型的频率和动力反应。用模型计算的结果与试验结果符合良好，计算模型基本合理。     

Single-cell stochastic modelling of the action of antimicrobial peptides on bacteria

Antimicrobial peptides (AMPs) produced by multi-cellular organisms as their immune system’s defence against microbes are actively considered as natural alternatives to conventional antibiotics. Although substantial progress has been achieved in studying the AMPs, the microscopic mechanisms of their functioning remain not well understood. Here, we develop a new theoretical framework to investigate how the AMPs are able to efficiently neutralize bacteria. In our minimal theoretical model, the most relevant processes, AMPs entering into and the following inhibition of the single bacterial cell, are described stochastically. Using complementary master equations approaches, all relevant features of bacteria clearance dynamics by AMPs, such as the probability of inhibition and the mean times before the clearance, are explicitly evaluated. It is found that both processes, entering and inhibition, are equally important for the efficient functioning of AMPs. Our theoretical method naturally explains a wide spectrum of efficiencies of existing AMPs and their heterogeneity at the single-cell level. Theoretical calculations are also consistent with existing single-cell measurements. Thus, the presented theoretical approach clarifies some microscopic aspects of the action of AMPs on bacteria.     

Investigation of the Pulsed Heterodyne of an Electro-Optically Q-Switched Radio-Frequency-Excited CO(2) Waveguide Laser with Two Channels

We present the results of our theoretical and experimental investigation of the pulsed heterodyne of an electro-optically Q-switched radio-frequency-excited CO(2) waveguide laser with two channels. We used a six-temperature model for CO(2) lasers to describe the process of dynamic emission in an electro-optically Q-switched laser. The calculated pulse waveforms are in good agreement with the experiment, which we used as the basis for our theoretical study of a pulsed laser heterodyne and its Fourier transform frequency spectrum. The experimental results are consistent with the theoretical analyses.     

形状记忆高分子材料记忆行为机理的理论分析

形状记忆高分子材料(SMP)具有优良的形状记忆功能,是继形状记忆合金(SMA)之后的又一热点研究领域.形状记忆机理的理论分析在SMP的研发与应用过程中起着至关重要的作用,理论分析往往对实验研究起着指导性的作用.目前对于形状记忆高分子材料记忆行为机理的理论研究还比较少.本文综述自形状记忆高分子材料发现20多年以来众多学者在形状记忆机理的理论方面的进展,并且对于今后理论研究的方向提出一些见解.     

熟制板栗蒸煮袋包装的设计

采用高温蒸煮袋技术,围绕蒸煮袋的结构及蒸煮袋材料的选择、材料厚度的确定、理论保质期的计算等内容对熟制板栗进行蒸煮袋袋装设计.通过理论分析计算,确定所设计的熟制板栗高温蒸煮袋的透明阻隔层材料为PET12/PVDC15/CPP50、不透明阻隔层材料为:PET12/Al9/CPP50;根据熟制板栗的最大允许透水量、所设计材料透湿系数和厚度,理论估算该高温蒸煮袋的保质期为4年,符合设计要求.     

金属材料静电起电理论分析及实验验证

目的减小包装材料在运输过程中产生的静电对周围或包装内电子产品的影响。方法对金属包装材料与空间粒子的摩擦起电机理进行理论分析,以固体接触分离起电为基础推导出摩擦起电电位的计算公式。为验证理论分析的正确性,以铝系金属材料为例进行摩擦起电实验。结果通过理论推导得到材料静电电位随时间以负指数规律增加,并逐步趋近饱和值,该饱和值与材料的性质有关,并与摩擦速度和接触面积成正比。在材料摩擦起电电位测试实验中,所得的静电电位变化曲线与理论分析相同,且连续测试后发现材料起电电位逐次降低;根据不同材料和不同摩擦速度时静电电位饱和值的变化情况,证实了金属材料摩擦起电电位与材料摩擦系数和接触面积的对应关系。结论通过理论分析和材料摩擦起电实验,得到了摩擦起电电位的增长规律,对减小静电危害起到指导意义。     

Effect of beam sizes on the amplitude and phase of photothermal deflection signals for both uniform and nonuniform heating

A detailed theoretical treatment of a one- (1D) and three-dimensional (3D) photothermal deflection (PTD) technique is presented. Important effects of the probe beam size occur in PTD experiments when the radius of this beam is of the order of magnitude of the thermal diffusion length. The calculation of this effect is checked by experiments in paraffin oil at low modulation frequency as well as for 1D and for 3D. In this last case, we have considered two kinds of deflection: normal and transverse, and we have studied their variation for different values of the pump beam radius. The coincidence between theoretical and experimental curves confirms the validity of our theoretical model.