On the Polygonal Wear Evolution of Heavy-Haul Locomotive Wheels due to Wheel/Rail Flexibility and Its Mitigation Measures

Wheel polygonal wear can immensely worsen wheel/rail interactions and vibration performances of the train and track,and ultimately,lead to the shortening of service life of railway components.At present,wheel/rail medium-or high-frequency frictional interactions are perceived as an essential reason of the high-order polygonal wear of railway wheels,which are potentially resulted by the flexible deformations of the train/track system or other external excitations.In this work,the effect of wheel/rail flexibility on polygonal wear evolution of heavy-haul locomotive wheels is explored with aid of the long-term wheel polygonal wear evolution simulations,in which different flexible modeling of the heavy-haul wheel/rail coupled system is implemented.Further,the mitigation measures for the polygonal wear of heavy-haul locomotive wheels are discussed.The results point out that the evolution of polygonal wear of heavy-haul locomotive wheels can be veritably simulated with consideration of the flexible effect of both wheelset and rails.Execution of mixed-line operation of heavy-haul trains and application of multicut wheel re-profiling can effectively reduce the development of wheel polygonal wear.This research can provide a deep-going understanding of polygonal wear evolution mechanism of heavy-haul locomotive wheels and its mitigation measures.

凸F-多边形内部的F-点数

An F-polygon is a simple polygon whose vertices are F-points, which are points of the set of vertices of a tiling of R~2 by regular triangles and regular hexagons of unit edge. Let f(v) denote the least possible number of F-points in the interior of a convex F-polygon K with v vertices. In this paper we prove that f(10) = 10, f(11) = 12,f(12) = 12.

Investigation on influencing factors of wheel polygonization of a plateau high-speed EMU train

Purpose–This study aims to investigate the cause of high-order wheel polygonization in a plateau high-speed electric multiple unit(EMU)train.Design/methodology/approach–A series of field tests were conducted to measure the vibration accelerations of the axle box and bogie when the wheels of the EMU train passed through tracks with normal rail roughness after re-profiling.Additionally,the dynamic characteristics of the track,wheelset and bogie were also measured.These measurements provided insights into the mechanisms that lead to wheel polygonization.Findings–The results of the field tests indicate that wheel polygonal wear in theEMUtrain primarily exhibits 14–16 and 25–27 harmonic orders.The passing frequencies of wheel polygonization were approximately 283–323 Hz and 505–545 Hz,which closely match the dominated frequencies of axle box and bogie vibrations.These findings suggest that the fixed-frequency vibrations originate from the natural modes of the wheelset and bogie,which can be excited by wheel/rail irregularities.Originality/value–The study provides novel insights into the mechanisms of high-order wheel polygonization in plateau high-speed EMU trains.Futher,the results indicate that operating the EMU train on mixed lines at variable speeds could potentially mitigate high-order polygonal wear,providing practical value for improving the safety,performance and maintenance efficiency of high-speed EMU trains.

A novel compensation method for polygonized mesa structures on(100) silicon substrate

A theoretical compensation method for polygonized mesa structures on（100） silicon substrate during the anisotropic etching process has been developed,which contains four stages as follows：prepare the information of the etching condition;predict the structure＇s undercutting profile;construct the topological structure of compensation patterns; and generate practical compensation patterns from the topological structure.The reasoning process is clearly stated,and detailed steps for the undercutting prediction and topological structure construction are summarized.Conclusions are also drawn about the rules which must be obeyed during the pattern generation process.The simulation and experimental results of some polygon structures are finally given to prove this method＇s validity and reliability.

基于Polygon-Nurbs混合建模的汽车造型数字化设计

文章阐述了汽车造型数字化设计中Polygon建模与Nurbs建模的特点与适用情境。提出了一种基于Polygon-Nurbs混合建模的汽车造型数字化设计方法。该建模方法的核心流程是先采用多边形确定形体,再使用Nurbs建模构建稳定的曲面。基于该混合建模思路,进行了汽车造型设计实践,证明了该建模方法能够发挥两种建模方式的优点,快速准确构建形体,并能生成高质量的曲面模型。

Differences of Polygonal Faults with Irregularly Polygonal Geometries: A Case Study from the Changchang Sag of Qiongdongnan Basin, Northern South China Sea

Polygonal faults(PFs)generally have a classic polygonal geometry in map view.However,under the influence of tectonic faults,diapirs,channels,and slopes,the classic polygonal geometry of PFs is not preserved,demonstrating differences(different characters)in map-view 3D seismic data covering an area of 334km^(2) of the Changchang(CC)sag,are used to document the mapview and cross-sectional characteristics of PFs.These data also help investigate the irregularly polygonal geometries of PFs due to the presence of influence factors,such as transtensional faults,submarine fans,channels,diapirs/gas chimneys,and the basal slope within the lower-middle Miocene strata.Results show that various irregularly polygonal geometries of PFs can be classified into enechelon and arcuate PFs,channel-segmenting and-bounding PFs,radial PFs,and rectangular PFs in map-view.En-echelon and arcuate PFs are induced by transtensional faults and exhibit a unique‘flower’structure in NE-and SE-trending cross-sections in the NW area of the study area.This finding is documented for the first time.Channel-segmenting PFs occur in the(northwest)low-amplitude muddy channel and are inhibited in the(southeast)high-amplitude sandy channel in the SW area.Radial PFs are radially aligned around a gas chimney/diapir containing some high-amplitude anomalies(HAAs)in the middle area.The presence of intrusive sandstones with HAAs along the periphery of the diapirs restricts the occurrence of PFs.Two high-amplitude submarine fans act as a mechanical barrier to the propagation of PFs.Meanwhile,the(moderate)slope in the NE area induces rectangular PFs.Additionally,the geneses of the PFs in the current study are comprehensively discussed.This study adds to our understanding of the differences between PFs with irregularly polygonal geometries.

Differences of polygonal faults related to upper Miocene channels:a case study from the Beijiao sag of Qiongdongnan basin,South China Sea

Deep-water coarse-grained channels are embedded within a polygonal fault tier,and the polygonal faults(PFs)present non-polygonal geometries rather than classic polygonal geometry in plan view.However,PFs present differences when they encounter deep-water(coarse-grained vs.fine-grained)channels with different lithology,which has not been further studied to date.Three-dimensional(3D)seismic data and a drilling well from Beijiao sag of Qiongdongnanbasin,South China Sea were utilized to document the plan view and cross-sectional properties of the PFs and their differences and genetic mechanism were investigated.Results show that,first,PFs can be divided morphologically into channel-segmenting PFs and channel-bounding PFs in plan view.The former virtually cuts or segments the axes of channels in highand low-amplitudes,and the latter nearly parallels the boundaries of the channels.Both are approximately perpendicular to each other.Secondly,channel-bounding PFs that related to low-amplitude channels are much longer than those of high-amplitude ones;channel-segmenting PFs related to low-amplitude channels are slightly longer than the counterparts related to high-amplitude channels.Lastly,the magnitudes(e.g.,heights)of the PFs are proportional to the scales(e.g.,widths and heights)of low-amplitude channels,whereas the magnitudes of the PFs are inversely proportional to the scales of high amplitude channels.Coarse-grained(high amplitude)channels act as a mechanical barrier to the propagation of PFs,whereas fine-grained(low-amplitude)channels are beneficial to the propagation and nucleation of PFs.Additionally,the genetic mechanism of PFs is discussed and reckoned as combined geneses of gravitational spreading and overpressure hydrofracture.The differences of the PFs can be used to reasonably differentiate coarse-grained channels from fine-grained channels.This study provides new insights into understanding the different geometries of the PFs related to coarse-grained and fine-grained channels and their genetic mechanism.

Drag Coefficient of a Non-Convex Polygonal Plate during Free Fall

Waterside creatures or aquatic organisms use a fin or web to generate a thrust force. These fins or webs have a non-convex section, referred to as a non-convex shape. We investigate the drag force acting on a non-convex plate during unsteady motion. We perform the experiment in a water tank during free fall. We fabricate the non-convex plate by cutting isosceles triangles from the side of a convex hexagonal plate. The base angle of the triangle is between 0° to 45°. The base angle is 0 indicates the convex hexagonal thin plate. We estimate the drag coefficient with the force balance acting on the model based on the image analysis technique. The results indicate that increasing the base angle by more than 30° increased the drag coefficient. The drag coefficient during unsteady motion changed with the growth of the vortex behind the model. The vortex has small vortices in the shear layer, which is related to the Kelvin-Helmholtz instabilities.

Results of Geomagnetic Studies on the Problem of Forecasting Strong Earthquakes in Uzbekistan

The article is devoted to the problem of forecasting strong earthquakes by the geomagnetic method. The geomagnetic method is widely used on this problem in seismically active regions of the world as one of the promising, informative and operational geophysical methods. The results of long-term geomagnetic studies on the problem of forecasting strong earthquakes in Uzbekistan are presented. Geomagnetic studies were carried out on the territories of the Tashkent, Ferghana, and Kyzylkum geodynamic polygons in the epicentral zones of strong earthquakes that occurred. Long-term, medium- and short-term precursors of earthquakes have been identified. Anomalous changes in the geomagnetic field associated with the decline in aftershock activity were also revealed. The dependence between the duration of the manifestation of long-term magnetic precursors and the magnitude of earthquakes is determined. Absolute proton magnetometers MMP-1, MV-01 (Russia), and G-856 (USA) were used to measure the geomagnetic field.

3D Fractals, Axiom of Algebra (Δn)n = +1

After having laid down the Axiom of Algebra, bringing the creation of the square root of -1 by Euler to the entire circle and thus authorizing a simple notation of the nth roots of unity, the author uses it to organize homogeneous divisions of the limited development of the exponential function, that is opening the way to the use of a whole bunch of new primary functions in Differential Calculus. He then shows how new supercomplex products in dimension 3 make it possible to calculate fractals whose connexity depends on the product considered. We recall the geometry of convex polygons and regular polygons.

Radio-Anatomical Study of Anterior Variants of the Polygon of Willis

The anterior system of the polygon of Willis plays an anastomotic role between the carotid territories and communicates with the posterior system. It ensures adequate cerebral blood flow in the event of internal occlusion. Its ability to redistribute blood flow depends on its morphology, the presence and size of the vessels that constitute it and their variants, knowledge of which is essential. The morphology of the carotid system is not constant and a number of variants are well recognized with greater hemodynamic importance. In this context, we undertook this work which aims to seek the anatomical variants of the anterior part of the PW;to determine the diameters of the vessels of the latter and to correlate these results with epidemiological data. We carried out a retrospective, descriptive and analytical study over a period of 4 months at Fann University Hospital, targeting patients who had undergone brain MRI with a 3D TOF sequence whatever the indication. Patients with lesions of cerebrovascular pathologies such as ischemia, hemorrhage, aneurysm, arteriovenous malformations or presenting a limited analysis examination due to the presence of kinetic or other artifact, were not included. Demographic data and anatomical variants were studied as well as the measurements of any continuous arterial segment greater than 0.8 mm in diameter. Those less than 0.8 mm in diameter were considered hypoplastic. The C3 segment of the internal carotid arteries, the A1 segment of the anterior cerebral arteries, the anterior communicating artery, constituted our main measurement sites. The sex ratio was 1.06, the mean age of the patients was 43 years ± 17.9 with extremes of 11 and 85 years. The anterior configuration of the polygon was complete in 57.5% representing 50% of men and 65.5% of women, in 56% of subjects under 40 years old and 58% in subjects over 40 years old. We noted a predominance of type a in 47% of patients followed by type g found in 35% of patients. The morphology of the anterior system of the Willis polygon is a function of its variants, some of which have greater hemodynamic importance than others. Its knowledge is essential for the management of cerebrovascular diseases.

一种汽车3D UI中带光影贴图车模的制作方法

汽车界面经历了从机械按键到液晶大屏的演进,最新车型采用3D UI和智能驾辅技术,打造沉浸式智能体验。本文详述了3D UI人机交互设计中的车模数据和光影效果优化方法,强调多边形模型在流畅运行和光影效果方面的关键作用。在车模数据量和光影效果优化中,需注意调整精度、贴图,平衡效果和效率。未来,随着车载系统算力提升,车辆有望实现更复杂的3D模型处理,为驾驶者和乘客带来更真实、沉浸的视觉体验。

Effect of surface microstructure of aluminum coating on corrosion properties of magnetic refrigerant gadolinium

AI coatings with different microstructures were prepared on the surface of Gd using the magnetron sputtering technique to improve its corrosion resistance. The corrosion behaviors for the pure Gd and Gd with Al coating in distilled water were studied using the mass loss and electrochemical performance. As a result, pure Gd without coating shows a certain amount of surface cracks under water flow conditions, whereas the polygonal Al coating decreases the path of the corrosive medium to body due to the existence of eroding pits structure. Compared with the polygonal structure Al coating and pure Gd, the lamellar structure of Al coating exhibits a higher electrochemical protection performance （e.g., a lower corrosion current and higher self-corrosion potential） and no occurrence of pitting corrosion. Due to an effective physical shield, the formation of the lamellar structure protected the inner Gd part from being corroded, and prolonged the duration of cathodic protection.

An Algorithm for Partitioning Polygons into Convex Parts

An algorithm for partitioning arbitrary simple polygons into a number of convex parts was presented. The concave vertices were determined first, and then they were moved by using the method connecting the concave vertices with the vertices of falling into its region B,so that the primary polygon could be partitioned into two subpolygons. Finally, this method was applied recursively to the subpolygons until all the concave vertices were removed. This algorithm partitions the polygon into O(l) convex parts, its time complexity is max(O(n),O(l 2)) multiplications, where n is the number of vertices of the polygon and l is the number of the concave vertices.

基于Polygon的雕塑法计算机辅助造型设计方法

计算机辅助设计技术已成为设计表现的必备手段,对于概念造型设计而言,接近传统手工方式的设计方法更易于被艺术设计师理解和接受。在对比目前主要计算机辅助造型方法的基础上,从分析传统手工雕塑造型的方式出发,针对概念设计和艺术造型设计的实际特征,提出了基于Polygon建模的雕塑法建模思路,给出了具体的建模步骤和合理布线的评价方法,并通过民间工艺品-泥塑马的造型实现过程进行了实例验证。实际运用证明,计算机雕塑建模方法对于艺术设计的三维软件建模理念具有较强的实用性,能够充分按照设计师的构思理念进行造型设计,对于创意设计而言更易于被造型设计师理解和运用。

一种实用的点/多面体分类算法

本文基于多面体表面的局部特性,提出了一种新的点/多面体分类算法,该算法适合于用边界表示法表示的任意多面体,可靠性高,具有很强的实用性。

新时代下三维动画专业基础课程设计的探索

目前许多高等院校都开设有三维动画专业,根据应用类型的不同涉及到如3DMax、Maya、Cinema4D等软件。同时,该专业的基础课程都会涉及到建模。三维模型的建模方式有很多种,从Polygon中的基本体扩展到平面图形的三维转换,从Nurbs中的编辑点挤出放样到二者之间的相互转换等。无论是哪一种方法,从布线结构的角度来看都遵守了一定的规律。笔者在多年任教过程中总结了一套关于三维动画基础课程的教学方法,通过具体分析一个模型的不同布线结构出发,来讨论什么样的布线才是最合适模型的。同时,通过分析当下游戏动画行业对模型制作的要求以及未来的发展趋势,衍生出笔者对如何教好三维动画专业课的一点思考。

Design and analysis of modular charge feeding mechanism

Aiming at the turning motion＇s disadvantages,including the instability of charge magazine caused by polygon effect and the disability of synchronously pushing modular charge of the current pushing mechanism,a new type of charge feeding mechanism is designed.It can not only select modular charge rapidly and steadily,but also push a certain amount of modular charge into the tray which is used to receive the charge synchronously.The selection and push principles of feeding mechanism are introduced,and a three-dimensional model is established.ADAMS is applied to simulation analysis of the feeding mechanism.The results show that the feeding mechanism can push the modular charge into the reception tray rapidly and steadily,which provides a theoretical basis for the practical design.

基于地铁轨道交通环控系统的虚拟现实与仿真关键技术研究

本文以地铁轨道交通环控系统项目为例,对虚拟现实与仿真关键技术进行了开发流程论述:提出了符合虚拟现实与仿真项目的模型制作规范;分别介绍了3ds Max和Unfold3D软件制作UV的技巧;针对纹理贴图详细阐述了AO贴图与高真实感的PBR材质制作流程;最后论述了UGUI控件、Unity3D功能组件以及C#脚本语言在地铁轨道交通环控系统项目开发中的作用。本文的研究对于虚拟现实与仿真项目的开发具有较好的理论指导和实际操作借鉴意义。

实事求是选择三维建模方法探讨

随着计算机技术的飞速发展,三维动画也随之越来越广泛,制作速度就显得非常重要。本文就建模这一模块来阐述如何实事求是地选择建模方法来提高建模速度。