摘要：The effect of porosity on compressive,bending,and tensile properties of the porous tantalum scaffolds fabricated by electron beam powder bed fusion(EB-PBF)was *** porous tantalum scaffolds with porosity from 69%to 77.8%were obtained by varying the designed porosity and adjusting the processing *** is found that the pores and unfused powder decrease with the increase of deposited energy *** decrease of porosity leads to an improvement in mechanical *** relevancy between compressive/bending/tensile yield strength and relative density can be described appropriately by exponential model,while the relationship between elastic modulus and relative density is in good agreement with the Gibson-Ashby *** the porous tantalum scaffolds exhibit good ductility in compressive,bending and tensile *** fragmentation of struts is observed during the compression process,but cracks are formed on the strut surface after 90°bending,mainly due to the high sensibility to defects caused by the oxide.

摘要：“碎片化知识”既不利于学生自主建构认知体系,又影响学生学科核心素养的培育。结构化教学是化解“碎片化教学”的有效措施。在结构化教学基本理念的指导下,历史结构化教学可从以下几个方面开展:一是融通素养内涵,确定整体化目标;二是整合教学内容,建构系列化知识;三是聚焦学习主题,设计逻辑化问题;四是触发学习动力,实施体系化评价。

摘要：为明确板桁结合加劲肋弦杆焊接残余应力分布特征,研究弦杆顶板焊接对腹板高强螺栓应力的影响。以温州瓯江北口大桥为背景,基于ABAQUS软件建立加劲梁下弦杆局部三维有限元模型,结合现场焊接顺序对焊接温度场和应力场进行数值模拟。

摘要：随着第三代红外探测器技术的快速发展,高工作温度红外探测器成为重要的发展方向。本文报道了在高工作温度碲镉汞红外探测器杜瓦结构小型化、低功耗、高可靠性方面的研究进展。通过杜瓦结构的优化设计,搭配旋转整体式低温制冷机K562S short,制备出组件体积为80 mm×61 mm×39 mm,重量为212 g,启动时间为2.5 min,工作温度达到150 K的高工作温度中波碲镉汞红外探测器,并初步完成了组件可靠性试验验证,为高工作温度碲镉汞红外探测器的工程化应用奠定了一定的基础,对高工作温度碲镉汞红外探测器的小型化、低功耗、高可靠性研究具有一定的指导意义。

摘要：冰川作为“固态水库”其融水对我国西北干旱地区区域水资源利用和生态系统可持续发展都具有重要意义,开展冰川科学研究并努力探索冰川研究新技术、新方法至关重要。本文基于机载激光雷达测量技术在冰川科学观测中的应用研究,从航空测量经验、冰川试验区域气象条件及航飞设备三方面开展冰川航测可行性分析及技术方法论证。结果表明,冰川激光雷达数据平面及高程误差绝对值均以≤10 cm为主,占比分别为86.6%(X方向)、86.5%(Y方向)、66.6%(XY方向)、90.0%(Z方向),误差值满足冰川观测要求。此次冰川试验验证了机载激光雷达测量技术在冰川科学观测中的可行性,实现了高海拔、高落差、极端天气地区航空测量技术突破,为促进我国冰川科学研究发展增添新动力。

摘要：将顶空平衡法和气相色谱仪相结合,通过自主设计和优化测试实现了技术升级,建立了可自动化进样并同步测定水中溶解CH_(4)和CO_(2)浓度的新型气相色谱系统及方法.结果表明,本系统线性范围宽且运行稳定,自动化程度更高,运行成本更低.该系统对CH_(4)的测定精密度优于0.16%,准确度优于0.02%,满足水中溶解CH_(4)浓度监测需求.基于本方法,于2022年8月对京杭大运河杭州段水体中溶解CH_(4)开展了试观测研究.结果显示:夏季京杭大运河杭州段水体中溶解CH_(4)浓度平均值为(642.4±423.3)nmol/L,饱和度平均值为(22310±14701)%,水-气界面CH_(4)扩散通量平均值为(548.57±603.70)μmol/(m^(2)·d),是大气CH_(4)的净源.根据该河段的面积,可估算观测期内CH_(4)的日均排放量约为1710mol,相当于大约38.31m^(3)天然气或约82.94kg碳.

摘要：In order to satisfy the requirements of beam measurement in the heavy ion medical machine and other small nuclear physics experiments, we designed and built a nuclear instrumentation module-based data acquisition system. This is composed of a set of functional modules and a purpose-built bus. One of the modules operates as a master, collecting data from the other slave modules. It then sends the data to the back-end computer via *** addition to the hardware, dedicated software has been designed and implemented. In this paper, we provide a detailed description of the architecture of the system, the data frame, and the software. The bus is the central part of the system. It can transmit data from the slave modules to the master at 33 MB/s. The frame used to transmit the data also ensures its integrity and monitors the hardware architecture. The client software is designed to process data in real time and store data on a hard disk for later analysis.

摘要：As an emerging class of crystalline porous materials, covalent organic frameworks（COFs） have been widely used as catalysts or catalyst supports. Flexible regulation of the pores and easy introduction of functional active sites onto the skeleton of COFs make them promising platforms for many catalysis applications. However, only a single function is generally observed in these COFs. Herein, we synthesized a negatively charged ionic COF（I-COF） and successfully incorporated functionalized counter ions, that is, metallic Mn2＋ and a coordination complex of manganese（Ⅱ） bipyridine complexes（[Mn（bpy）2]2＋）, via a simple ion exchange process. The resulting I-COFs can act as effective heterogeneous catalysts for epoxidation reactions. We envisage that with this type of ionic architecture, a variety of other functional cations could be exchanged into the frameworks, thus making the COF a versatile platform for different applications.

摘要：目的 设计一种低频交变磁场发生装置,高效率地去除H62黄铜管内的表面缺陷,提高其表面质量,延长其使用寿命。方法 采用闭合铁芯的方式设计一种低频磁场发生装置,利用EDEM软件对磁场中的磁性磨粒进行运动仿真分析;对电磁线圈的缠绕方式、通电方式进行设计,并利用Ansys软件对不同的线圈缠绕方式和通电方式所产生的磁场进行模拟分析。数控车床夹持管件旋转,并与磁场发生装置相配合,使管件中的磁性磨粒在磁场中磁化,并紧贴管件内表面进行研磨抛光。使用触针式表面粗糙度测量仪和超景深3D电子显微镜,对研磨前后的样品进行检测分析。结果 基于三端缠绕方式,采用2种不同的通电方式对管件进行研磨加工,采用相对型通电方式研磨6min后,H62黄铜管内的表面粗糙度由原始的0.618μm降至0.373μm。采用相邻型通电方式研磨6 min后,H62黄铜管内的表面粗糙度由原始的0.667μm降至0.081μm。结论 利用低频交变磁场能够实现研磨工具(磁性磨粒)的循环更新,提高磁性磨粒的利用率。在采用三端缠绕方式通电时所产生的磁场强度更大,更适合于磁粒研磨加工。采用相邻型通电方式(N-N-S-S磁极排布)加工时,研磨压力更大,大幅缩短了加工时间,去除了管件内壁的原始缺陷。

摘要：基于光纤的大传输带宽、微型传能通道、抗电磁干扰等优势,本文设计了一种光载信息能量同传方案.它基于光纤一体化分布式链路,结合微波光子模拟收发前端,同步实现能量远程配送与高频宽带信号的采集传输.首先,设计并测试了光纤传能(Power over Fiber,PoF)链路:高功率激光经多模光纤链路传输2 km后转换为百毫瓦级电能,为远端模块供电或电池充电.在此基础上,设计并测试了基于PoF的光载无线通信(Radio over Fiber,RoF)和电磁干扰检测链路.RoF链路实现了2.4 GHz频段的16QAM-OFDM宽带信号的2 km单模光纤传输;电磁干扰远程采集与监测链路实现了对高铁GSM-R(Global System for Mobile Communications-Railway)无线频段的带内干扰、邻带干扰和带外干扰的检测与识别等.相关方案和系统在易燃易爆、强电磁干扰、强辐射等特殊场景具有重要应用价值.