PEGDA/NIPAM共聚物水凝胶的溶胀性能及体积相变研究

以IRGACURE2959为光引发剂,聚乙二醇双丙烯酸酯(PEGAD)和N-异丙基丙烯酰胺(NIPAM)为单体,通过紫外光引发光聚合合成了PEGDA/NIPAM共聚物水凝胶.研究了不同单体质量比凝胶材料在不同温度和pH值下的溶胀性能,测试凝胶在不同温度水中的体积相变.研究结果表明,水凝胶的平衡溶胀率随着NIPAM质量浓度增大而增大,随着环境温度的升高而减小,随着环境pH的增大而增大;NIPAM引入后,随着温度升高达到凝胶低临界溶解温度(LCST)时,凝胶平衡溶胀率及溶胀比减小明显加快,发生体积相变;随着NIPAM质量浓度的增大,凝胶溶胀饱和率减小,凝胶具备良好的延缓溶胀性能.     

Effect of Sn-doping on the sintering process of MgB<Subscript>2</Subscript> and its superconductive properties

Bulk (Mg_1.02B₂)_1−x Sn _x samples (x = 0.0, 0.01, 0.03 and 0.05) were synthesized by in situ sintering at 850 °C for one hour. Based on the phase identification and microstructure observation, the Mg₂Sn and Sn impurities are found as the main impurities in Sn-doped samples. According to the magnetization measurements, the low doping level of Sn was observed to have small influence on the grain connectivity, and thus a high critical current density was maintained at low field. However, the values of the critical current density at high field in the Sn-doped samples show a little decrease.     

移动在线实时绘制技术研究综述

移动在线实时绘制技术受移动互联网发展的驱动,为3维可视化、计算机视觉、虚拟现实、增强现实、扩展现实和元宇宙等新兴研究领域提供了核心技术的支撑。本文以在线实时绘制技术为切入点,探讨了该技术在移动端、Web端、云端和多端协同这4类平台下的发展重心和研究现状,并深度阐述了工业级在线云平台的实施方案。首先,针对移动端的在线实时绘制,分析了近年来移动端绘制硬件构架设计的优化方向;探讨了在功耗和带宽受到制约的情况下移动端如何对渲染算法进行加速,如何对高功耗的光线跟踪算法进行优化;列举了包括图形应用程序编程接口(application programming interface,API)和游戏引擎在内的移动端渲染工具。然后,针对Web端在线实时绘制,分析了Web端的3D渲染机制,梳理了以3D场景的轻量化预处理、大规模3D场景的细粒度化网络传输、3D场景的对等传输以及Web3D在线特效渲染为代表的Web端在线绘制的关键技术(尤其面向大规模3D场景),列举了国内外知名Web3D引擎并探讨了主流游戏引擎对Web3D应用的支持。再后,针对云端在线实时绘制,从应用托管、资源调度和串流这三大云平台的核心功能入手,调研了以串流应用优化技术为核心的在线云绘制现状。此后,从多端绘制任务分摊机制入手,分析了以“端云”协同和“端边云”协同为目标的在线多端协同绘制的发展。最后,以当前工业级在线云绘制平台为研究对象,分析了包括微软、英伟达、Unity、酷家乐等一线云绘制企业的在线实时云绘制平台方案,验证了移动在线绘制技术在工业界的实用性。     

A paddlewheel dinuclear Cu(II) compound coordinated with TTF-py redox ligand

A new paddlewheel dinuclear complex with a pyridyl-tetrathiafulvalene (TTF-py) ligand has been obtained and characterized crystallographically as [(DMT-TTF-py)₂Cu₂(OAc)₄]·2C₆H₆ (1). Meanwhile a mononuclear compound [(DMT-TTF-py)₂Cu(PhCOO)₂(CH₃OH)₂]·2CH₂Cl₂ (2) was also isolated. UV–vis spectra and cyclic voltammogram of the paddlewheel complex were studied, showing that compound 1 can undergo an oxidization to form a stable cation of [(DMT-TTF-py)₂Cu₂(OAc)₄]²⁺. By this strategy, compound 3, [(DMT-TTF-py)₂Cu₂(OAc)₄](I₃)₂ as a radical salt, has been prepared and its conductivity of powder sample was 1.02 × 10^?3 ohm^?1 cm^?1. Antiferromagnetic coupling of Cu(II)–Cu(II) was found from the results of ESR spectra, but the coupling between the radical–Cu(II) was very weak.     

Strengthening mechanisms of a new 700 MPa hot rolled Ti-microalloyed steel produced by compact strip production

A new hot rolled titanium-microalloyed steel with yield strength of 700 MPa has been developed by CSP (compact strip production) process based on commercial weather resistant steel. EBSD results showed that the average size of its grains with high angle boundaries (>15°) was 3.3 μm. High-density dislocations and large number of nanometer particles were observed in the steel product by TEM. X-ray analysis on the electrolytically extracted phase from the steel indicated that fraction of MX phase was 0.0793 wt%, in which the particles smaller than 10 nm accounted for 33.7%. The contribution of precipitation hardening resulting from nanometer particles was calculated as approximate 158 MPa. The commercial weather resistant steel, reference steel for comparison with 450 MPa yield strength, was also prepared and investigated. It can be concluded that grain refinement is still a major strengthening mechanism in this high strength steel, but precipitation hardening of nanometer TiC precipitates is the dominant factor to increasing the yield strength in new developed steel compared with the reference steel.     

FCC汽油加氢脱硫/降烯烃工艺技术的研究

在分析催化裂化汽油硫和烯烃分布不均匀的基础上,对催化裂化汽油进行分馏,开发出了活性高和稳定性好的重馏分辛烷值改进催化剂和选择性加氢脱硫催化剂及其工艺技术。采用该工艺技术对RFCC汽油进行轻馏分碱洗抽提脱硫醇,重馏分辛烷值改进/选择性加氢脱硫等改质处理,再按分馏比例回调,产品汽油烯烃含量为24.2v%,较原料油降低了16.0v%,芳烃含量为19.2v%,较原料油提高了4.1v%,硫含量为41.5ppm,总脱硫率为85.46%,RON为87.8,较原料油提高0.4个单位,液收99.1%,可生产符合国Ⅳ规范的清洁汽油。     

A holistic integrated dynamic design and modelling approach applied to the development of ultraprecision micro-milling machines

Ultraprecision machines with small footprints or micro-machines are highly desirable for micro-manufacturing high-precision micro-mechanical components. However, the development of the machines is still at the nascent stage by working on an individual machine basis and hence lacks generic scientific approach and design guidelines. Using computer models to predict the dynamic performance of ultraprecision machine tools can help manufacturers substantially reduce the lead time and cost of developing new machines. Furthermore, the machine dynamic performance depends not only upon the mechanical structure and components but also the control system and electronic drives. This paper proposed a holistic integrated dynamic design and modelling approach, which supports analysis and optimization of the overall machine dynamic performance at the early design stage. Based on the proposed approach the modelling and simulation process on a novel 5-axis bench-top ultraprecision micro-milling machine tool – UltraMill – is presented. The modelling and simulation cover the dynamics of the machine structure, moving components, control system and the machining process, and are used to predict the overall machine performance of two typical configurations. Preliminary machining trials have been carried out and provided the evidence of the approach being helpful to assure the machine performing right at the first setup.     

CdS量子点的合成和指纹检测研究

本工作提出以谷胱甘肽(GSH)为修饰试剂合成了高量子产率的硫化镉量子点,并应用其对非渗透性客体玻璃上的潜在指纹进行显现。结果发现,显现出的指纹清晰可辨,且与背景之间的反差好。该方法具有简便、快速、灵敏、安全、经济等特点。     

西北农林科技大学3号教学楼的鉴定与加固

西北农林科技大学3号教学楼建于1934年,钢筋混凝土框架结构,主体部分地上3层,局部塔楼7层。该建筑被列为陕西省文物保护单位。经过70多年的服役,材料的老化和结构的损伤导致承载能力下降、耐久性降低、抗震能力不足,加之汶川地震影响,部分填充墙出现裂缝。校方委托专业检测单位对该建筑进行了检测和评估,并委托设计单位依据评估报告及相应规范对结构进行加固设计。     

水泥电杆参数的估算

介绍了架空线路水泥电杆运行参数的估算口诀。分析了估算口诀、估算公式的来源和物理意义。指出了从电气理论和现场条件约束的角度对口诀加以归纳和总结,将实践经验与理论知识有机结合,有利于普及电工口诀的应用;在供配电作业现场进行水泥电杆的安装、运行和维护工作中运用电工口诀可以达到提高工效的目的。