载荷对D2车轮钢滑动磨损表层微观组织和性能影响

目的研究滑动磨损条件下,载荷变化对D2车轮钢表层微观组织和磨损性能的影响。方法利用MRH-30(环块)滑动摩擦磨损试验机进行滑动磨损试验。使用金相显微镜(OM)、场发射扫描电镜(SEM)、X射线衍射仪(XRD)和场发射透射电镜(TEM)等设备,分析滑动磨损后表层微观组织、表面磨损形貌和硬度变化。结果不同载荷条件下,随着磨损时间的增加,轮轨试样磨损量逐渐增加。200 N载荷条件下,(环状)车轮试样的磨损量大于100 N车轮试样磨损量,但200 N钢轨(块状)试样的磨损量却低于100 N钢轨试样。滑动磨损后,在不同载荷条件下,车轮试样表面主要形成长条状白层和不连续的月牙状白层。在200 N载荷条件下,由于车轮试样的磨损量较高,其白层厚度和表面白层硬度都小于100 N载荷条件下的车轮试样。在200 N载荷条件下,车轮试样表面更易形成不连续的月牙状白层。由于轮轨试样表面存在微凸体,高载荷会加速车轮试样表面局部微凸体发生严重塑性变形,导致月牙状白层的形成。在白层内片状渗碳体发生明显溶解和铁素体晶粒显著细化。结论车轮表面白层对磨损性能有明显影响。滑动磨损过程中,高载荷条件下,月牙状白层和周边微观组织界面易形成裂纹,裂纹会逐渐沿着界面向内部扩展,导致不连续月牙状白层发生剥落,降低车轮试样表面的硬度,加速车轮试样磨损。另一方面,高载荷会加速无白层区域塑性变形,导致其形成棘轮失效,从而加速磨损。

技术进步对建筑业能源利用效率的影响研究--基于C-D函数

近年来,环境保护与碳排放问题一直是世界关注的焦点,如何降低碳排放量,提高碳排放效率是世界各国需要克服的科学技术难关。建筑业作为碳排放占比较大的行业之一,是实现“双碳”目标的重要突破口,而技术进步已成为建筑业碳减排的重要途径。本研究基于2010—2020年中国建筑业发展情况,运用C-D函数分析技术进步对能源利用效率的影响机理。研究发现建筑业固定资产净值投入、建筑材料消耗对能源利用效率的增长影响最为显著,而自2015年起,建筑业技术进步逐渐对能源利用效率起正向作用。本研究以宏观视角分析技术进步对能源利用效率的影响,丰富了建筑业碳排放研究的理论方法,为我国建筑业减碳工作提出针对性的建议。

Process,Material,and Regulatory Considerations for 3D Printed Medical Devices and Tissue Constructs

Three-dimensional(3D)printing is a highly automated platform that facilitates material deposition in a layer-by-layer approach to fabricate pre-defined 3D complex structures on demand.It is a highly promising technique for the fabrication of personalized medical devices or even patient-specific tissue constructs.Each type of 3D printing technique has its unique advantages and limitations,and the selection of a suitable 3D printing technique is highly dependent on its intended application.In this review paper,we present and highlight some of the critical processes(printing parameters,build orientation,build location,and support structures),material(batch-to-batch consistency,recycling,protein adsorption,biocompatibility,and degradation properties),and regulatory considerations(sterility and mechanical properties)for 3D printing of personalized medical devices.The goal of this review paper is to provide the readers with a good understanding of the various key considerations(process,material,and regulatory)in 3D printing,which are critical for the fabrication of improved patient-specific 3D printed medical devices and tissue constructs.

K·U·D模式下基于通感理念体验的初中音乐单元作业设计路径探究

本文根据对K·U·D模型进行概念内涵进行分析,并据此设定具体的目标导向。通过与通感理念相结合的方式丰富教学体验形式,探讨不同的体验方式类型。教学实践部分围绕创设情境活动和设计单元作业进行阐述,包括多维度定制作业框架、多感官联动体验学习、多层次协作合作交流、多角度构建评价反馈以及多视角反思作业设计。每个环节都不仅反映了对音乐教育深度的追求,也体现了争取在学生群体中实现个性化作业设计和全面发展的教育理念。

A Building Information Modeling-Life Cycle Cost Analysis Integrated Model to Enhance Decisions Related to the Selection of Construction Methods at the Conceptual Design Stage of Buildings

Life Cycle Cost Analysis (LCCA) provides a systematic approach to assess the total cost associated with owning, operating, and maintaining assets throughout their entire life. BIM empowers architects and designers to perform real-time evaluations to explore various design options. However, when integrated with LCCA, BIM provides a comprehensive economic perspective that helps stakeholders understand the long-term financial implications of design decisions. This study presents a methodology for developing a model that seamlessly integrates BIM and LCCA during the conceptual design stage of buildings. This integration allows for a comprehensive evaluation and analysis of the design process, ensuring that the development aligns with the principles of low carbon emissions by employing modular construction, 3D concrete printing methods, and different building design alternatives. The model considers the initial construction costs in addition to all the long-term operational, maintenance, and salvage values. It combines various tools and data through different modules, including energy analysis, Life Cycle Assessment (LCA), and Life Cycle Cost Analysis (LCCA) to execute a comprehensive assessment of the financial implications of a specific design option throughout the lifecycle of building projects. The development of the said model and its implementation involves the creation of a new plug-in for the BIM tool (i.e., Autodesk Revit) to enhance its functionalities and capabilities in forecasting the life-cycle costs of buildings in addition to generating associated cash flows, creating scenarios, and sensitivity analyses in an automatic manner. This model empowers designers to evaluate and justify their initial investments while designing and selecting potential construction methods for buildings, and enabling stakeholders to make informed decisions by assessing different design alternatives based on long-term financial considerations during the early stages of design.

基于物联网的建设工程施工安全D-S诊断研究

针对建筑业生产安全事故频发且传统施工安全诊断方法准确率不高的问题,基于物联网技术在建设工程施工安全应用的优势,构建了建设工程施工安全诊断指标体系,采取AHP-熵权法组合赋权的方式确定了诊断指标权重。建立了基于D-S证据理论的施工安全诊断模型,并经案例分析验证了模型的有效性,为建筑企业安全管控和事故预防提供依据。

Advances in 3D printing scaffolds for peripheral nerve and spinal cord injury repair

Because of the complex nerve anatomy and limited regeneration ability of natural tissue,the current treatment effect for long-distance peripheral nerve regeneration and spinal cord injury(SCI)repair is not satisfactory.As an alternative method,tissue engineering is a promising method to regenerate peripheral nerve and spinal cord,and can provide structures and functions similar to natural tissues through scaffold materials and seed cells.Recently,the rapid development of 3D printing technology enables researchers to create novel 3D constructs with sophisticated structures and diverse functions to achieve high bionics of structures and functions.In this review,we first outlined the anatomy of peripheral nerve and spinal cord,as well as the current treatment strategies for the peripheral nerve injury and SCI in clinical.After that,the design considerations of peripheral nerve and spinal cord tissue engineering were discussed,and various 3D printing technologies applicable to neural tissue engineering were elaborated,including inkjet,extrusion-based,stereolithography,projection-based,and emerging printing technologies.Finally,we focused on the application of 3D printing technology in peripheral nerve regeneration and spinal cord repair,as well as the challenges and prospects in this research field.

3D printing of functional bioengineered constructs for neural regeneration: a review

Three-dimensional(3D)printing technology has opened a new paradigm to controllably and reproducibly fabricate bioengineered neural constructs for potential applications in repairing injured nervous tissues or producing in vitro nervous tissue models.However,the complexity of nervous tissues poses great challenges to 3D-printed bioengineered analogues,which should possess diverse architectural/chemical/electrical functionalities to resemble the native growth microenvironments for functional neural regeneration.In this work,we provide a state-of-the-art review of the latest development of 3D printing for bioengineered neural constructs.Various 3D printing techniques for neural tissue-engineered scaffolds or living cell-laden constructs are summarized and compared in terms of their unique advantages.We highlight the advanced strategies by integrating topographical,biochemical and electroactive cues inside 3D-printed neural constructs to replicate in vivo-like microenvironment for functional neural regeneration.The typical applications of 3D-printed bioengineered constructs for in vivo repair of injured nervous tissues,bio-electronics interfacing with native nervous system,neural-on-chips as well as brain-like tissue models are demonstrated.The challenges and future outlook associated with 3D printing for functional neural constructs in various categories are discussed.

香港地区D&B模式经验分析及对内地EPC模式优化建议研究

工程总承包(EPC)模式及设计与建造(D&B)模式已成为内地及港澳大型或复杂工程项目的主要实施模式。对比香港地区D&B模式与内地EPC模式异同,并以香港地区儿童医院项目为例,深入分析D&B项目在组织架构模式、业主要求、设计管理、精细化管理及现场施工管理等方面先进经验。为促进内地EPC工程总承包模式可持续发展及工程项目高质量交付,提出发包节点选择、项目组织形式、业主要求文件、计价模式、总承包商管理等方面建议。

3D Model Construction and Ecological Environment Investigation on a Regional Scale Using UAV Remote Sensing

The acquisition of digital regional-scale information and ecological environmental data has high requirements for structural texture,spatial res-olution,and multiple parameter categories,which is challenging to achieve using satellite remote sensing.Considering the convenient,facilitative,and flexible characteristics of UAV(unmanned air vehicle)remote sensing tech-nology,this study selects a campus as a typical research area and uses the Pegasus D2000 equipped with a D-MSPC2000 multi-spectral camera and a CAM3000 aerial camera to acquire oblique images and multi-spectral data.Using professional software,including Context Capture,ENVI,and ArcGIS,a 3D(three-dimensional)campus model,a digital orthophoto map,and multi-spectral remote sensing map drawing are realized,and the geometric accuracy of typical feature selection is evaluated.Based on a quantitative remote sensing model,the campus ecological environment assessment is performed from the perspectives of vegetation and water body.The results presented in this study could be of great significance to the scientific management and sustainable development of regional natural resources.

联合改进U-Net模型和D-InSAR技术采矿沉陷提取方法

矿产资源开采导致的地表沉陷不仅是矿区国土空间开发利用需要考虑的重要因素,而且对地下非法开采的区域具有明显的指征作用。矿产资源开采一般具有分布范围较广、分布不均且较分散的特点,因此快速、准确地识别并提取大区域内采矿沉陷的空间分布非常必要。本研究基于合成孔径雷达差分干涉测量技术(differential interferometric synthetic aperture Radar,D-InSAR)得到矿区多时相差分干涉相位图,并使用深度学习FCN-8s,PSPNet,Deeplabv3和U-Net模型训练网络开展采矿沉陷智能识别,结果显示U-Net模型具有较高的检测精度且用时较短。为提高采矿沉陷的语义分割提取精度,在传统U-Net模型中引入高效通道注意力模块进行训练。结果表明改进的U-Net模型与传统模型相比,在测试集上采矿沉陷对应的交并比提升2.54百分点,为大范围采矿沉陷时空分布提取问题提供新的解决方法。

Enhanced Constructability Using 4D Plus Modelling in Brownfield Sites

In the oil and gas industry, operations in greenfield sites are straightforward. However, there are increased risks, such as damage to existing facilities, unknown site conditions, and other complexities in brownfield sites. In addition to these physical risks, task scheduling is also complex, as vessels need to be replaced during a turnaround. To mitigate the risks of site conditions and realize a truncated schedule for Saudi Aramco’s operations, 3D laser scanning was combined with 3D modeling, clash detection, and time. This integrated approach minimized the shutdown period, which resulted in cost savings, heightened safety, and enhanced stakeholder communications.

南京市新型研发机构建设探索——以南京建邺区为例

新型研发机构作为南京市推动科技创新和成果转化的重要举措,在成果转化、人才集聚、企业孵育等方面取得了积极成效。文章以南京市建邺区新型研发机构为例,探讨新型研发机构建设的发展现状、取得成效、存在问题及下一步发展建议,为南京市新型研发机构的发展建设提供参考。

U-G-S模式下现代大学附属学校建设的路径思考

U-G-S(大学-政府-学校)三方联动是上海师范大学近年来建设现代大学附属学校的主要模式,上海师范大学、各区政府与中小学校高效协同合作,发挥各方优势,主动服务上海市政府建设“五个新城”的城市战略,办老百姓家门口的好学校。大学附属学校分为挂牌学校和新建学校两种类型,研究从内在机制、实践路径和建设成效三个方面对两类学校的变革发展进行深度剖析,以期为大学附属学校建设提供宝贵经验。

平煤十矿曲面D型钢管混凝土支架支护技术

U型钢支架作为一种传统的巷道支护方式,在围岩破碎和复杂地应力条件下并不能起到很好的支护作用。以平煤十矿-320开采水平专用回风下山支护为工程背景,研发了曲面D型钢管混凝土支架,通过设置与U型钢支架支护的对比试验巷道,观测巷道围岩动态及矿压显现规律,对曲面D型钢管混凝土支架支护技术进行观测研究。现场观测表明:曲面D型钢管混凝土支架支护的巷道顶板在初期经一段时间较明显下沉后,支架的支护作用逐渐显现,巷道表面位移速率明显降低,最终巷道相对位移量趋于稳定,能够有效控制围岩变形,取得了显著的支护效果。

ERK抑制剂U0126通过下调cyclin D1与survivin蛋白表达抑制乳腺癌细胞增殖

目的 研究ERK通路抑制剂U0126对乳腺癌细胞增殖的抑制作用,并探讨其调控机制。方法培养人乳腺癌细胞株MCF-7、MDA-MB231,将细胞分组干预,MTT法检测各组细胞增殖情况;流式细胞仪检测各组细胞周期及细胞凋亡;Western blot检测细胞中p-ERK/ERK、cyclin D1、survivin及cleaved caspase-3蛋白表达。结果 MTT结果显示,U0126干预24、48 h后,MCF-7、MDA-MB231细胞抑制率明显增加(P<0.01);MCF-7、MDA-MB231细胞经U0126干预24 h后,检测细胞周期及细胞凋亡,G 0/G 1期细胞比例较对照组明显增加,S及G 2期细胞比例下降(P<0.05);而干预组细胞凋亡率较未干预组明显增多(P<0.01);U0126处理人乳腺癌细胞2 h后,可阻断ERK的磷酸化,减少cyclin D1的蛋白表达,抑制survivin而上调cleaved caspase-3的表达,与对照组相比差异有显著性(P<0.01)。结论 U0126通过阻断MCF-7、MDA-MB231细胞中ERK信号通路,调控cyclin D1,将细胞周期阻断在G 0/G 1期,抑制survivin而增加cleaved caspase-3表达,增加细胞凋亡,继而使乳腺癌细胞MDA-MB231、MCF-7的增殖受到抑制。

Joint 3D traveltime calculation based on fast marching method and wavefront construction

3D traveltime calculation is widely used in seismic exploration technologies such as seismic migration and tomography. The fast marching method （FMM） is useful for calculating 3D traveltime and has proven to be efficient and stable. However, it has low calculation accuracy near the source, which thus gives it low overall accuracy. This paper proposes a joint traveltime calculation method to solve this problem. The method firstly employs the wavefront construction method （WFC）, which has a higher calculation accuracy than FMM in calculating traveltime in the small area near the source, and secondly adopts FMM to calculate traveltime for the remaining grid nodes. Due to the increase in calculation precision of grid nodes near the source, this new algorithm is shown to have good calculation precision while maintaining the high calculation efficiency of FMM, which is employed in most of the computational area. Results are verified using various numerical models.

建筑3D打印数字建造技术研究应用综述

3D打印技术起源于20世纪80年代末,也称为"增材制造"或"快速原型"技术。21世纪以来,随着3D打印技术的引入,数字建造成为了建筑领域数字化发展的趋势。本文对国内外现有建筑3D打印技术相关研究及应用情况进行了分析,依据使用材料和打印工艺将目前主要建筑3D打印技术归纳为三类:基于混凝土分层喷挤叠加的增材建造方法、基于砂石粉末分层粘合叠加的增材建造方法和大型机械臂驱动的材料三维构造建造方法。文章对未来建筑3D打印的研究方向提出了若干展望,包括材料理论及新材料研发、机械设备及工艺改良、软硬件协同和智能化控制研究、3D打印构件及结构力学性能研究、技术适用性及工作模式研究、技术标准体系研究、社会经济效益评价研究等方面。

基于U3D的航空发动机涡轮装配模拟器开发

通过设计开发航空发动机涡轮装配模拟器,旨在改变传统教学实习的方式,改善实习条件和更新实习内容。文章系统地介绍了航空发动机涡轮装配模拟器的设计原理和组成,阐述了设计中的关键技术,并给出了模拟器的实现方案。模拟器采用CATIA和Acrobat 3D完成,发动机三维模型采用U3D格式,通过JavaScript实现了对U3D图形的控制。模拟器已经在本科教学中得到应用,实践表明该模拟器有很好的实用性和创新性。

基于3D数字路面的整车耐久性能评价方法研究

鉴于传统的路谱采集方法受限于样车试验,开发周期长,且无法有效预测后期参数变化和评估全新车型,本文中在传统整车动力学载荷分析的基础上,建立了轮胎高频模型和试验场3D数字路面模型,提出了路面-轮胎-悬架-车身的这一完整传递路径的整车虚拟路谱动态响应分析和耐久性能评价方法。通过生成基于3D数字路面的动态载荷,可在项目开发早期进行汽车结构耐久性能评估。结果表明,用此方法获得的数据与传统轮心力传感器采集的路谱数据相当接近,能有效识别零件的风险位置和逐步免除开发阶段的路谱数据采集,在开发早期实现结构耐久性精确评估。