基于BIM的公路工程标准化EBS分解方法

工程结构分解(EBS)是公路工程全寿命周期信息化管理的基础。为了提高公路工程建设期信息化水平,基于BIM技术应用,提出了公路工程标准化EBS分解方法。标准化分解方法根据工程中不同路段,梳理专业划分以及空间位置划分原则,并依据行业标准,确定标准化EBS结构的叶子节点,提供公路工程EBS结构树模板示例。研究结果旨在提高高速公路数字化交付中的数据处理标准建设,为实施公路工程数字化提供基础支持。

Microstructures and micromechanical behaviors of high -entropy alloys investigated by synchrotron X-ray and neutron diffraction techniques: A review

High-entropy alloys(HEAs)possess outstanding features such as corrosion resistance,irradiation resistance,and good mechan-ical properties.A few HEAs have found applications in the fields of aerospace and defense.Extensive studies on the deformation mech-anisms of HEAs can guide microstructure control and toughness design,which is vital for understanding and studying state-of-the-art structural materials.Synchrotron X-ray and neutron diffraction are necessary techniques for materials science research,especially for in situ coupling of physical/chemical fields and for resolving macro/microcrystallographic information on materials.Recently,several re-searchers have applied synchrotron X-ray and neutron diffraction methods to study the deformation mechanisms,phase transformations,stress behaviors,and in situ processes of HEAs,such as variable-temperature,high-pressure,and hydrogenation processes.In this review,the principles and development of synchrotron X-ray and neutron diffraction are presented,and their applications in the deformation mechanisms of HEAs are discussed.The factors that influence the deformation mechanisms of HEAs are also outlined.This review fo-cuses on the microstructures and micromechanical behaviors during tension/compression or creep/fatigue deformation and the application of synchrotron X-ray and neutron diffraction methods to the characterization of dislocations,stacking faults,twins,phases,and intergrain/interphase stress changes.Perspectives on future developments of synchrotron X-ray and neutron diffraction and on research directions on the deformation mechanisms of novel metals are discussed.

Direct visualization of laser-driven dynamic fragmentation in tin by in situ x-ray diffraction

We present a novel method for investigating laser-driven dynamic fragmentation in tin using in situ X-ray diffraction.Our experimental results demonstrate the feasibility of the method for simultaneously identifying the phase and temperature of fragments through analysis of the diffraction pattern.Surprisingly,we observe a deviation from the widely accepted isentropic release assumption,with the temperature of the fragments being found to be more than 100 K higher than expected,owing to the release of plastic work during dynamic fragmentation.Our findings are further verified through extensive large-scale molecular dynamics simulations,in which strain energies are found to be transferred into thermal energies during the nucleation and growth of voids,leading to an increase in temperature.Our findings thus provide crucial insights into the impact-driven dynamic fragmentation phenomenon and reveal the significant influence of plastic work on material response during shock release.

Intensity correlation properties of x-ray beams split with Laue diffraction

Beam splitting is one of the main approaches to achieving x-ray ghost imaging, and the intensity correlation between diffraction beam and transmission beam will directly affect the imaging quality. In this paper, we investigate the intensity correlation between the split x-ray beams by Laue diffraction of stress-free crystal. The analysis based on the dynamical theory of x-ray diffraction indicates that the spatial resolution of diffraction image and transmission image are reduced due to the position shift of the exit beam. In the experimental setup, a stress-free crystal with a thickness of hundredmicrometers-level is used for beam splitting. The crystal is in a non-dispersive configuration equipped with a double-crystal monochromator to ensure that the dimension of the diffraction beam and transmission beam are consistent. A correlation coefficient of 0.92 is achieved experimentally and the high signal-to-noise ratio of the x-ray ghost imaging is anticipated.Results of this paper demonstrate that the developed beam splitter of Laue crystal has the potential in the efficient data acquisition of x-ray ghost imaging.

Dispersion Relations in Diffraction in Time

In agreement with Titchmarsh’s theorem, we prove that dispersion relations are just the Fourier-transform of the identity, g(x′)=±Sgn(x′)g(x′), which defines the property of being a truncated functions at the origin. On the other hand, we prove that the wave-function of a generalized diffraction in time problem is just the Fourier-transform of a truncated function. Consequently, the existence of dispersion relations for the diffraction in time wave-function follows. We derive these explicit dispersion relations.

Surface diffraction beamline at the SSRF

BL02U2 of the Shanghai Synchrotron Radiation Facility is a surface diffraction beamline with a photon flux of 5.5×10^(12) photons/s at 10 keV and a beam size of 160µm×80µm at the sample site.It is dedicated to studying surfaces(solid-vacuum,solid-gas)and interfaces(solid-solid,solid-liquid,and liquid-liquid)in nanoscience,condensed matter,and soft matter systems using various surface scattering techniques over an energy range of 4.8-28 keV with transmission and reflection modes.Moreover,BL02U2 has a high energy resolution,high angular resolution,and low beam divergence,which can provide excellent properties for X-ray diffraction experiments,such as grazing incident X-ray diffraction,X-ray reflectivity,crystal truncation rods,and liquid X-ray scattering.Diversity of in situ environments can also be provided for the samples studied.This paper describes the setup of the new beamline and its applications in various fields.

Tailoring electron vortex beams with customizable intensity patterns by electron diffraction holography

An electron vortex beam(EVB) carrying orbital angular momentum(OAM) plays a key role in a series of fundamental scientific researches, such as chiral energy-loss spectroscopy and magnetic dichroism spectroscopy. So far, almost all the experimentally created EVBs manifest isotropic doughnut intensity patterns. Here, based on the correlation between local divergence angle of electron beam and phase gradient along azimuthal direction, we show that free electrons can be tailored to EVBs with customizable intensity patterns independent of the carried OAM. As proof-of-concept, by using computer generated hologram and designing phase masks to shape the incident free electrons in the transmission electron microscope, three structured EVBs carrying identical OAM are tailored to exhibit completely different intensity patterns. Furthermore, through the modal decomposition, we quantitatively investigate their OAM spectral distributions and reveal that structured EVBs present a superposition of a series of different eigenstates induced by the locally varied geometries. These results not only generalize the concept of EVB, but also demonstrate an extra highly controllable degree of freedom for electron beam manipulation in addition to OAM.

Numerical Study on the Effect of Gap Diffraction on the Hydrodynamic Performance of A Floating Breakwater

Two-dimensional(2D)flume experiments are useful in investigating the performances of floating breakwaters(FBs),including hydrodynamic performances,motion responses,and mooring forces.Designing a reasonable gap between the flume wall and the FBs is a critical step in 2D flume tests.However,research on the effect of the gap on the accuracy of 2D FB experimental results is scarce.To address this issue,a numerical wave tank is developed using CFD to estimate the wave-FB interaction of a moored dual-cylindrical FB,and the results are compared to experimental data from a previously published work.There is good agreement between them,indicating that the numerical model is sufficiently accurate.The numerical model is then applied to explore the effect of gap diffraction on the performance of FBs in2D experiments.It was discovered that the nondimensional gap length L_(Gap)/W_(Pool)should be smaller than 7.5%to ensure that the relative error of the transmission coefficient is smaller than 3%.The influence of the gap is also related to the entering wave properties,such as the wave height and period.

Diffraction deep neural network-based classification for vector vortex beams

The vector vortex beam(VVB)has attracted significant attention due to its intrinsic diversity of information and has found great applications in both classical and quantum communications.However,a VVB is unavoidably affected by atmospheric turbulence(AT)when it propagates through the free-space optical communication environment,which results in detection errors at the receiver.In this paper,we propose a VVB classification scheme to detect VVBs with continuously changing polarization states under AT,where a diffractive deep neural network(DDNN)is designed and trained to classify the intensity distribution of the input distorted VVBs,and the horizontal direction of polarization of the input distorted beam is adopted as the feature for the classification through the DDNN.The numerical simulations and experimental results demonstrate that the proposed scheme has high accuracy in classification tasks.The energy distribution percentage remains above 95%from weak to medium AT,and the classification accuracy can remain above 95%for various strengths of turbulence.It has a faster convergence and better accuracy than that based on a convolutional neural network.

电解铜箔截面微观组织的EBSD分析

目的通过树脂包埋结合离子截面抛光的制备方法,实现铜箔样品的截面EBSD分析,进而利用截面EBSD分析方法探究电流密度对铜箔组织性能的影响。方法通过使用热固性树脂对铜箔进行包埋,使用加热平台使胶体凝固,对得到的包埋好的铜箔试样在砂纸上进行截面打磨,放入截面离子抛光仪中进行离子切割,样品制备完成后,将样品取下。使用电子背散射(EBSD)作为电镜附件,进行晶体学取向的表征。结果结合截面微观组织的EBSD分析方法,分析了电流密度对铜箔组织性能的影响,结果表明,随着电流密度的增大,电解铜箔的晶粒尺寸呈现出先减小后增大的趋势,孪晶密度和位错密度呈现出先增大后减小的趋势,抗拉强度在45 A/dm^(2)时达到最大547.05 MPa。结论该方法可以利用EBSD分析软件自动分析铜箔截面的晶粒粒度分布、孪晶密度等,并将这些微观结构特征与力学性能结果进行详细对比分析,验证了电流密度对铜箔组织和性能的显著影响。

The Crystal Structure Study of CaSrFe0.75Co0.75Mn0.5O6−δ by Neutron Diffraction

The crystal structure of CaSrFe0.75Co0.75Mn0.5O6−δ is investigated through neutron diffraction techniques in this study. The material is synthesized using a solid-state synthesis method at a temperature of 1200˚C. Neutron diffraction data is subjected to Rietveld refinement, and a comparative analysis with X-ray diffraction (XRD) data is performed to unravel the structural details of the material. The findings reveal that the synthesized material exhibits a cubic crystal structure with a Pm-3m phase. The neutron diffraction results offer valuable insights into the arrangement of atoms within the lattice, contributing to a comprehensive understanding of the material’s structural properties. This research enhances our knowledge of CaSrFe0.75Co0.75Mn0.5O6−δ, with potential implications for its applications in various technological and scientific domains.

基于WBS和EBS体系的铁路项目路基工程分解探索与实践

项目分解是将复杂项目具体化的惯用管理方法,在工程精细化管理中起着重要的作用,而项目分解方式往往因项目类别和管理要求的不同呈现出多样性的特点。本文基于当前铁路行业数字化、智能化的发展要求,综合利用Uni FormatⅡ体系(EBS)和Master FormatⅡ(WBS)体系分解原理,结合铁路工程项目管理惯例,以铁路工程施工质量验收标准、铁路工程工程量清单计价指南为基础,提出一种可用于BIM模型参数化创建及项目全周期质量、进度、验工计价管理的路基工程分解方法,即以工作单元分解和工程结构分解为核心的两阶段综合分解方法,并选取某项目路基工程进行了实践,实践结果表明,该方法可满足建设数字工程的需要,可为同类型铁路项目分解提供经验借鉴。

基于EBS-YOLOv5的钢铁表面缺陷检测

随着人工智能在工业检测领域的应用日益增加,如何快速准确地检测缺陷成为了一个热点问题。钢铁是一种重要的工业原材料,针对钢铁表面缺陷的检测问题,提出了一种基于YOLOv5的改进模型。该模型主要有2点改进:一是在头部加入SENet(压缩和激励网络)注意力机制,增强全局检测能力,使模型能够学习不同通道的权重信息;二是加入EVC(显性视觉中心)模块,使得模型在关注全局信息的同时,也不忽略层内局部特征和角部信息。使用了公开的数据集NEU-DET(东北大学缺陷检测任务)验证了其可行性,试验结果表明,EBS-YOLOv5模型比起YOLOv5s的准确率有了较明显的提升,mAP50(平均精度指标)提高了6.2%,仍然保持了154的检测帧率,满足工业场景下对钢铁表面的检测需求。

Analysis of Orange Peel Defect in St14 Steel Sheet by Electron Backscattered Diffraction (EBSD)

In this paper, the orange peel defect in the surface range of the st14 steel sheet has been investigated using the electron backscattered diffraction (EBSD) technique. It has been found that the orange peel defect in the st14 steel sheet was resulted from the local coarse grains which were produced during hot-rolling due to the critical deformation in dual-phase zone. During deep drawing, the coarse grains with {100}<001> microtexture can slip on the {112}<111> slip system to form bulging and yields orange peel defects, while the coarse grains with {112}<110> orientation do not form the defect as the Schmid factor of {112}<111> slip system in it equals zero.

Analysis of surface orange peel of aluminum-alloy automobile sheet by using of EBSD and X-ray diffraction

The formation cause of orange peel of aluminum-alloy automotive sheet after tensile deformation was analysed by using X-ray diffraction and electron back-scattered diffraction(EBSD).The test results showed that formation cause of surface orange peel after tensile deformation related to product texture and nonuniform deformation during the tensile process.The grain size has significant effect on deformation uniform and texture formation.Coarse grains were easy to produce nonuniform deformation and texture,which would produce surface orange peel after tensile deformation.

EBSD技术及其在金属材料中的研究应用

电子背散射衍射技术(EBSD)作为分析材料晶体结构、物相分布、织构以及取向差的新型研究方法,通过介绍EBSD的系统构成以及基本原理,对比其与传统分析技术之间的优缺点,结合具体实例说明EBSD在金属材料中织构、取向和晶粒尺寸等方面的应用。

Tracking the phase transformation and microstructural evolution of Sn anode using operando synchrotron X-ray energy-dispersive diffraction and X-ray tomography

Tin(Sn)holds great promise as an anode material for next-generation lithium(Li)ion batteries but suffers from massive volume change and poor cycling performance.To clarify the dynamic chemical and microstructural evolution of Sn anode during lithiation and delithiation,synchrotron X-ray energydispersive diffraction and X-ray tomography are simultaneously employed during Li/Sn cell operation.The intermediate Li-Sn alloy phases during de/lithiation are identified,and their dynamic phase transformation is unraveled which is further correlated with the volume variation of the Sn at particle-and electrode-level.Moreover,we find that the Sn particle expansion/shrinkage induced particle displacement is anisotropic:the displacement perpendicular to the electrode surface(z-axis)is more pronounced compared to the directions(x-and y-axis)along the electrode surface.This anisotropic particle displacement leads to an anisotropic volume variation at the electrode level and eventually generates a net electrode expansion towards the separator after cycling,which could be one of the root causes of mechanical detachment and delamination of electrodes during long-term operation.The unraveled chemical evolution of Li-Sn and deep insights into the microstructural evolution of Sn anode provided here could guide future design and engineering of Sn and other alloy anodes for high energy density Li-and Na-ion batteries.

基于EBS+WBS的公路桥梁检测系统构建与应用

为推动公路桥梁检测方式由传统检测向数字化检测转变,力争实现公路桥梁检测从数据采集、数据传输、数据分析计算到成果输出的全过程数字化,以EBS+WBS为核心,采用SOA设计理念构建出一套基于B/S架构的公路桥梁检测系统。实践结果表明,系统以检测数据为载体串联公路桥梁检测业务,应用功能完整覆盖了桥梁多要素、全周期检测业务,并以此实现了BIM+GIS在桥梁检测中的应用。

基于EBSD系统的工业纯铁微观结构观测方法

简述了电子背散射衍射(EBSD)的技术原理和试样的制备工艺,简要说明了工业纯铁EBSD试样的制备过程和测试参数选择等。利用EBSD技术分析表征了未发生塑性变形的工业纯铁、发生塑性变形的工业纯铁以及塑性变形后回复再结晶的工业纯铁。通过数据处理分析,研究讨论了三种不同处理条件下的工业纯铁的组织变化规律,包括晶粒尺寸、晶粒取向、晶粒取向差和晶界特征等信息。通过实例进一步表明EBSD是材料微观组织结构表征中一种非常有效的分析手段。

Thermal expansivity of geikielite and ilmenite utilizing in-situ synchrotron X-ray diffraction at high temperature

The unit-cell parameters and volumes of geikielite(MgTiO_(3))and ilmenite(FeTiO_(3))were investigated at high temperatures up to 700 K and ambient pressure,using in-situ angle-dispersive synchrotron X-ray diffraction.No phase transition was detected over the experimental temperature range.Using(Berman in J Petrol29:445-522,1988.10.1093/petrology/29.2.445)equations to fit the temperature-volume data,the volumetric thermal expansion coefficients at ambient conditions(α_(V0))of MgTiO_(3) and FeTiO_(3) were obtained as follows:2.55(6)×10^(-5)K^(-1)and 2.82(10)×10^(-5)K^(-1),respectively.We infer that the larger effective ionic radius of Fe^(2+)(Ⅵ)(0.78 A)than that of Mg^(2+)(Ⅵ)(0.72?)renders FeTiO_(3)has a larger volumetric thermal expansivity than MgTiO_(3).Simultaneously,the refined axial thermal expansion coefficients under ambient conditions areα_(a0)=0.74(3)×10^(-5)K^(-1)andα_(c0)=1.08(5)×10^(-5)K^(-1)for the aaxis and c-axis of MgTiO_(3),respectively,andα_(a0)=0.95(5)×10^(-5)K^(-1)andα_(c0)=0.92(12)×10^(-5)K^(-1)for the aaxis and c-axis of FeTiO_(3),respectively.The axial thermal expansivity of MgTiO_(3) is anisotropic,but that of FeTiO_(3) is nearly isotropic.We infer that the main reason for the different axial thermal expansivity between MgTiO_(3) and FeTiO_(3) is that the thermal expansion mode of the Mg-O bond in MgTiO_(3) is different from that of the Fe-O bonds in FeTiO_(3).