Fault Analysis and Structure Optimization of Traveling Transmission System of Shuttle Car

This paper firstly introduces the common faults of traveling transmission system of shuttle car.Secondly,by analyzing the characteristics of shuttle car structure,the layout of traveling transmission system and the common faults on shuttle car,this paper concludes that"internal holding torque"is the main cause of faults.Finally,this paper proposes a corresponding optimization design scheme to reduce the impact of"internal torque",and calculates the relevant results through the finite element simulation analysis method.Through these analyses and calculations,it is shown that the method can effectively reduce the probability of failure of traveling transmission system of shuttle car.

Data-Driven Structural Design Optimization for Petal-Shaped Auxetics Using Isogeometric Analysis

Focusing on the structural optimization of auxetic materials using data-driven methods,a back-propagation neural network(BPNN)based design framework is developed for petal-shaped auxetics using isogeometric analysis.Adopting a NURBSbased parametric modelling scheme with a small number of design variables,the highly nonlinear relation between the input geometry variables and the effective material properties is obtained using BPNN-based fitting method,and demonstrated in this work to give high accuracy and efficiency.Such BPNN-based fitting functions also enable an easy analytical sensitivity analysis,in contrast to the generally complex procedures of typical shape and size sensitivity approaches.

Study of the Porosity of the Tiles out of Vibrated Mortar by Microstructural Analysis

The promotion and the popularization of the micro concrete tiles in any locality obligation with a will of durable development pass by a standard of quality, which is based on the results of scientific and technical research taking account of local specificities. This work proposes to study the porosity of the micro concrete by micro structural analysis. From this study, it comes out that the variation of porosity compared to the ratio of the fine gravels (s/(s + g)) is decreasing. Indeed more the granular ratio increases less low is the density of pores of material. The decrease of porosity according to the granular rate is not infinite;it tends towards a minimum starting from a rate of fine gravel close to 50%. The results obtained justify well the ratio of fine gravel practised by tileries.

The Structural,Dielectric,Lattice Dynamical and Thermodynamic Properties of Zinc-Blende CdX(X=S,Se,Te) from First-Principles Analysis

The structural, dielectric, lattice dynamical and thermodynamic properties of zinc-blende CdX （X=S, Se, Te） are studied by using a plane-wave pseudopotential method within the density-functional theory. Our calculated lattice constants and bulk modulus are compared with the pubfished experimental and theoretical data. In addition, the Born effective charges, electronic dielectric tensors, phonon frequencies, and longitudinal opticaltransverse optical splitting are calculated by the linear-response approach. Some of the characteristics of the phonon-dispersion curves for zinc-blende CdX （X= S, Se, Te） are summarized. What is more, based on the lattice dynamical properties, we investigate the thermodynamic properties of CdX （X= S, Se, Te） and analyze the temperature dependences of the Helmholtz free energy F, the internal energy E, the entropy S and the constant-volume specific heat Cv. The results show that the heat capacities for CdTe, CdSe, and CdS approach approximately to the Petit-Dulong limit 6R.

Structural Analysis and Improved Design of the Gearbox Casing of a Certain Type of Tracked Vehicle

Loads on a gearbox casing of a certain type of tracked vehicle were calculated according to the engine＇s full load characteristic curve and the worst load condition where the gearbox operated while the tracked vehicle was running, and then stiffness and strength of the casing were analyzed by means of Patran/Nastran software. After a- nalysis, it was found that the casing satisfied the Mises ＇ yield condition; however, the stress distribution was hetero- geneous, and stresses near the bearing saddle bores of the casing were higher while those in other regions were much less than the allowable stress. For this reason, thicknesses of the casing wall on bearing assembling holes needed in- creasing, while those in other places can decrease. After much structural improving and re-analysis, the optimal casing design was found, and its weight decreased by 5% ; the casing still satisfied the Mises yield criterion and the stress distribution was more homogeneous.

Analysis of the Structure of Shakespeare's Sonnets

The sonnet is a kind of lyrics with restrict forms which cannot depart from the contents. Shakespeare's sonnets are like a valuable flower blossoming in the England poetry garden during the age of Renaissance and a bright pearl sparkling in the world's poetry treasury. This paper will analyze his sonnets from the perspective of the structure and then interpret the meanings behind those words, which can demonstrate the importance of the connection between the forms and the contents.

全国市场VS区域市场:碳市场有效性的差异、成因及其对策

对碳市场有效性进行测度、把握碳市场运行效率,有利于进一步推动碳交易机制优化和效率提升。本文以全国碳排放权交易市场及8个区域试点碳市场为研究对象,以2021年7月16日至2023年6月16日碳配额成交均价为样本,运用结构突变检验法与重标极差分析法对各个碳市场整体与阶段运行效率进行测度。研究结果表明:全国碳市场整体运行效率偏低,仅第一阶段达到了弱式有效水平;在区域试点碳市场中北京碳市场达到弱式有效,若考虑结构突变点时,则上海、广东、湖北、深圳和重庆碳市场达到阶段性弱式有效。在此基础上,进一步剖析了全国碳市场有效性较低的影响因素,并有针对性地提出对策建议。

A search for evidence of small-scale inhomogeneities in dense cores from line profile analysis

In order to search for intensity fluctuations on the HCN（1-0） and HCO＋（1-0） line pro- files, which could arise due to possible small-scale inhomogeneous structure, long-term observations of high-mass star-forming cores S140 and S199 were carried out. The data were processed by the Fourier filtering method. Line temperature fluctuations that exceed the noise level were detected. Assuming the cores consist of a large number of randomly moving small thermal fragments, the total number of frag- ments is - 4 × 106 for the region with linear size - 0.1 pc in S140 and - 106 for the region with linear size - 0.3 pc in S 199. Physical parameters of fragments in S 140 were obtained from detailed modeling of the HCN emission in the framework of the clumpy cloud model.

S环形无碳小车结构设计与分析

依据全国大学生工程训练综合能力竞赛S环形赛道挑战赛要求,实现无碳小车完成S环形轨迹路径并通过设置障碍桩,详细设计了一辆利用斜推杆凸轮控制转向的无碳小车。文中对小车的整体结构进行了设计,基于设计尺寸模拟仿真出轨迹重合度最高的凸轮,设计出的无碳小车具有结构简单、可靠性高及成本低等优点。为此,利用SolidWorks软件建立三维模型,利用Creo规划轨迹图,利用MATLAB仿真小车行走路线并生成凸轮。文中设计的无碳小车对初次设计的人员具有指导意义。

基于ANSYS-Workbench的4BM-250型苎麻剥麻机机架有限元分析与结构优化

剥麻机的机架对剥麻机的整机性能有重要的影响。为避免剥麻机工作过程中机架出现结构强度不足和共振问题,采用solidworks软件建立4BM-250型苎麻剥麻机机架的三维模型,基于ANSYS-Workbench软件对剥麻机机架进行静力学分析与模态分析。静力学分析结果表明:机架在静载荷下的最大位移为0.14 mm,最大应力为23.71 Mpa,最大应力小于机架材料结构钢的屈服强度极限,因此机架结构在条件载荷下的强度和刚度满足设计要求。模态分析结果表明:机架前6阶的固有频率为0,7~12阶模态的频率为25.28~89.58 Hz,柴油机转子的运动频率与机架的第8阶固有频率在同一区间范围。对照第8阶频率的振动类型及变形特点对机架模型进行改进优化,并对优化后的模型进行模态分析,结果表明:机架的前1~6阶模态的振动频率为0,第7~12阶模态的频率分别为17.92、35.56、44.56、53.94、57.41、70.25 Hz。对比改进前,改进后模型的各模态频率均有所下降,平均下降15.81%,且各阶模态下的变形均较小,主要部件变形量均在10 mm以下,改进后的结构综合力学性能有明显提升。该研究可为机械结构部件的研发设计提供参考。

Convergent Neuroimaging and Molecular Signatures in Mild Cognitive Impairment and Alzheimer’s Disease:A Data-Driven Meta-Analysis with N=3,118

The current study aimed to evaluate the susceptibility to regional brain atrophy and its biological mechanism in Alzheimer’s disease(AD).We conducted data-driven meta-analyses to combine 3,118 structural magnetic resonance images from three datasets to obtain robust atrophy patterns.Then we introduced a set of radiogenomic analyses to investigate the biological basis of the atrophy patterns in AD.Our results showed that the hippocampus and amygdala exhibit the most severe atrophy,followed by the temporal,frontal,and occipital lobes in mild cognitive impairment(MCI)and AD.The extent of atrophy in MCI was less severe than that in AD.A series of biological processes related to the glutamate signaling pathway,cellular stress response,and synapse structure and function were investigated through gene set enrichment analysis.Our study contributes to understanding the manifestations of atrophy and a deeper understanding of the pathophysiological processes that contribute to atrophy,providing new insight for further clinical research on AD.

能量分辨质谱区分与检测人参皂苷同分异构体20(S)-Rf和Rg_(1)

将连续变化的碰撞能量与串联质谱相结合,建立了能量分辨质谱(Energy-resolved mass spectrometry,ERMS)分析方法用以区分和检测人参皂苷同分异构体20(S)-Rf和Rg_(1).ERMS将子离子与母离子强度的比值定义为强度分数(Intensity fraction,IF),两个子离子强度的比值定义为强度比(Intensity ratio,IR),并通过IF和IR分别对连续变化的碰撞能量作图建立特征碎片离子的IF和IR曲线.虽然20(S)-Rf和Rg_(1)的串联质谱图无明显差异,但是多元统计分析结果显示其特征碎片离子[M-Glc-H]-,[M-2Glc-H]-和[M-2Glc-C_(6)H_(12)-H]-的IF和IR曲线差异显著,有明显的区分边界,可以直接区分20(S)-Rf和Rg_(1).进一步利用ERMS实时分析了原人参三醇型皂苷生物转化产物中20(S)-Rf和Rg_(1)的相对摩尔含量.结果表明,ERMS不需液相色谱分离即可实现20(S)-Rf和Rg_(1)的快速区分和相对含量检测.

水下采油树S密封结构优化与试验研究

S密封作为水下采油树的非金属密封圈,是水下安全生产的关键部件之一。以S密封为研究对象,进行了结构和密封机理的研究并对其结构参数进行优化。通过建立有限元仿真模型,研究了密封圈截面长度、截面宽度、弹簧直径及圆弧半径等参数对密封圈性能的影响规律,并根据影响显著性采用响应面法对密封圈的关键结构参数进行优化分析,以最小等效应力与最大接触应力为目标,对密封圈结构参数进行优化。将优化后的S密封与优化前进行对比,结果得出在安全性能和密封性能上S密封均有显著的提升;最后通过静压试验对S密封进行了密封性能测试,试验结果表明S密封满足密封性能要求。研究方法和结果可为S密封以及其他类似结构密封圈的结构优化提供理论依据及数据参考。

基于Solidworks的汽车搬运器结构设计及有限元分析

文章介绍了一种汽车搬运器,该装置主要适用于停车区,主要用于解决当前日常生活中停车难、挪车难的问题。该汽车搬运器利用连接机构、支撑机构和夹持机构三部分核心结构,可实现对不同轴距的汽车进行搬运。文章基于Solidworks完成汽车搬运器结构装配设计及simulation插件的有限元分析,对该汽车搬运器结构分别进行应力应变有限元分析。验证了文章中汽车搬运器的强度、刚度和稳定性。

汽车车身造型设计与气动力分析

为研究车身造型对气动力的影响,根据人机工程相关参数,运用Rhino软件的非统一有理B样条(non-uniform rational B-splines, NURBS)建模技术,构建车身外形,并采用计算流体动力学方法对其外流场进行仿真,得到气动力特性。流场中气流始终附着在车身表面没有出现分离,表明车身造型合理,有利于减小气动阻力。针对尾部结构进行曲线再造,改进后的模型的气动阻力明显减小;附加尾翼和鸭尾造型气动升力减小,侧倾力矩减弱,有利于提高汽车对地面的附着力,提高稳定性,更适合于赛车。文中采用的方法可为设计符合汽车空气动力学特性的车身造型方案及风洞试验提供理论参考。

基于CoMFA方法对氟喹啉-4-酮衍生物的分子建模与设计

基于比较分子力场分析法(CoMFA),建立了16个已知活性的氟喹啉-4-酮衍生物抗肝癌活性(K_(S))的三维定量构效关系(3D-QSAR)模型,并研究该类结构与生物活性之间的关系.CoMFA模型的交叉验证系数(Q^(2))为0.338,拟合验证系数(R^(2))是0.987.此3D-QSAR模型的预测值与实验值基本一致,表明该模型具有显著的统计学可靠性和预测能力.该模型中立体场、静电场贡献率依次为41.9%、58.1%.根据3D-QSAR模型分析结果进行分子设计并完成活性预测,预测结果印证了分析的合理性,为该系列化合物的结构优化提供了合理建议.

B/S结构下基于Web Services技术的空间分析方法的研究

文本重点研究了B/S体系结构下WebServices技术在GIS中的应用,分析了其中的关键技术,包括B/S体系结构、WebServices技术,进行了基于WebServices技术的GIS空间分析技术的研究,最后指出了基于WebServices技术的WebGIS发展前景。

基于ANSYS的智能换电小车底盘结构静态分析

基于有限元分析软件ANSYS Workbench,以结构静态分析理论为基础,对乘用车电池快换系统的关键设备智能换电小车底盘结构进行静态学分析,包括模型简化、模型导入、网格划分、施加载荷和约束等过程,得出不同型号工字钢的等效应力及总变形云图,并对优化后的结构进行分析验证,为系统整体开发和优化提供参考,推动对与电动汽车产业相配套的乘用车电池快换系统关键设备的快速发展。

MIBS深度差分故障分析研究

给出了MIBS算法及故障分析原理,基于不同深度的故障模型,提出了3种针对MIBS差分故障分析方法,并进行实验验证。实验结果表明,由于其Feistel结构和S盒差分特性,MIBS易遭受深度差分故障攻击,最好的结果为在第30轮左寄存器导入1次4bit故障,故障位置和故障差分值未知,可将64bit主密钥搜索空间降低到224,经1min暴力破解恢复完整主密钥。此外,该故障分析方法也可为其他使用S盒的分组密码差分故障分析提供一定思路。

北京沙尘暴的干盐湖盐渍土源——单颗粒物分析和XPS表面结构分析

2002年3月20日北京特大沙尘暴565个单颗粒物分析结果表明,S和Cl是唯一呈现显著正相关的一对元素.同时含有S和Cl的单颗粒物检出率高达82.5%,其中S和Cl的含量还高于所有颗粒物平均值.同时含有S、Cl和Na的颗粒物检出率为62.0%,其中Na的含量更比所有颗粒物平均值高出1.4倍.PMF因子分析显示NaCl和Na2SO4是北京沙尘暴S和Cl显著相关的那些单颗粒物的主要成分.沙尘暴样品中SO42-和Cl-浓度呈高度线性相关.X射线光电子谱对气溶胶表面结构分析显示,Na和S在沙尘暴颗粒物表面的百分含量比北京非沙尘暴和内蒙古地区气溶胶样品高.这些同时含有S、Cl和Na,且S和Cl显著正相关,Na相对富集的颗粒物多数来自于沙尘暴途中所经过的其表层土成分富含氯化物和硫酸盐的干盐湖盐渍土地区.证明了北京沙尘暴不仅来自于其源头沙漠,沙尘暴所经过的包括干盐湖盐渍土的大范围干旱、半干旱地区的表层土也是其主要来源.