Hot deformation and processing maps of as-sintered CNT/Al-Cu composites fabricated by flake powder metallurgy

The deformation behaviors of as-sintered CNT/Al-Cu composites were investigated by isothermal compression tests performed in the temperature range of 300?550 °C and strain rate range of 0.001?10 s^?1 with Gleeble 3500 thermal simulator system. Processing maps based on dynamic material model (DMM) were established at strains of 0.1?0.6, and microstructures before and after hot deformation were characterized by scanning electron microscopy (SEM), electron backscatter diffraction (EBSD) and high-resolution transmission electron microscopy (HRTEM). The results show that the strain has a significant influence on the processing maps, and the optimum processing domains are at temperatures of 375?425 °C with strain rates of 0.4?10 s^?1 and at 525?550 °C with 0.02?10 s^?1 when the strain is 0.6. An inhomogeneous distribution of large particles, as well as a high density of tangled dislocations, dislocation walls, and some sub-grains appears at low deformation temperatures and strain rates, which correspond to the instability domain. A homogeneous distribution of fine particles and dynamic recrystallization generates when the composites are deformed at 400 and 550 °C under a strain rate of 10 s^?1, which correspond to the stability domains.     

武汉火神山、雷神山医院污水处理工程设计

火神山、雷神山医院是为集中收治新型冠状病毒肺炎(COVID-19)患者而设立的传染病专科医院,其污水处理系统设计均采用"预消毒接触池+化粪池+提升泵站(含粉碎格栅)+调节池+MBBR生化池+混凝沉淀池+接触消毒池"处理工艺。MBBR工艺实现了低温下污水中污染物的高效去除,两级消毒工艺保障了病毒100%消灭,同时污水站地基下方按垃圾填埋场标准铺设HDPE膜,保障雨水污水全收集并进行消毒后排放,污泥经消毒脱水后按危险废物集中清运处理,废气统一收集经除臭消毒后排放,实现雨污水、污泥、废气的全收集和全处理。当前,火神山、雷神山医院污水处理系统运行稳定,相关出水指标均已达到设计要求,其中COD稳定低于50mg/L,氨氮稳定在2 mg/L以下,余氯稳定在13 mg/L附近,污染物去除与消毒效果均十分稳定。     

石墨烯量子点的制备与表征

介绍了一种改进的溶剂热法制备石墨烯量子点(GQDs)。该方法以N,N-二甲基甲酰胺(DMF)和氧化石墨烯(GO)作为溶剂和原料,过程中会对GO进行微波膨胀预处理,然后进行反应。分别采用紫外可见吸收、光致发光、红外、透射电镜对石墨烯量子点进行结构、形貌以及荧光性能的表征。通过该方法制备的GQDs的荧光发射光谱表明其具有可激发性且具有良好的荧光性能。     

增材制造技术在模具制造中的应用研究

介绍了增材制造技术的优点,阐述了增材制造技术在模具制造中的各种制造方法及特点,叙述了利用增材制造技术实现模具复合材料和梯度功能材料的应用,指出了增材制造技术的应用前景。     

基于非支配遗传算法的自动化仓库动态货位优化

针对存有随机数量货物的机床零部件自动化立体仓库(AS/RS)中存在的货位规划难题,提出了一种基于动态的仓储模式与Pareto遗传算法的AS/RS货位优化方法。该方法以能耗最低和效率最高为基本原则规划库区和优化分配货架,完成货位编号和货品编号;以堆垛机行驶时间和货架稳定性为优化目标,建立货位多目标优化的数学模型;采用第二代非支配排序遗传算法得到动态货位优化的Pareto最优解。仿真实例计算结果表明,该方法使货物的出入库能量消耗、出入库效率以及货架的稳定性等指标得到较大改善。     

Research on the Spatial–Temporal Changes of Regional Morphology of Residential Neighborhoods in County-Level Cities of China: Cases Studies on Qingcheng County,Wu’an City,Changxing County,Lianjiang County,and Jintang County

The extensive growth in most Chinese cities at the expense of local identities of living settlement. Taking the 60 residential neighborhoods in county-level cities of varied climate zones in China as examples, this paper explores their spatial–temporal changes and differences in morphology, based on 12 morphological indicators through Principal Component Analysis and correlation analysis by ArcGIS 10.2, SPSS 22, and Origin 2021. The results show that 1) the construction dating of the 60 sample neighborhoods conforms to the development of China’s housing reform; 2) the spatial morphology of residential neighborhoods in county-level cities of different climate zones could be charaterized by 5 factors, i.e. neighborhood shape, development intensity, neighborhood size, layout order, and aggregation degree; 3) the disparities in the spatial morphology of residential neighborhoods in the same climate zone in different period of time are mostly indicated with 3 morphological indicators, i.e. Building Density, Neighborhood Area, and Green Space Ratio; rather, the morphology of residential neighborhoods built during a same period of time varies largely between climate zones, mainly indicated with Green Space Ratio, Degree of Building Angle Disorder, and Degree of Building Distance Disorder; and 4) China’s housing policies, climatic conditions, residential building patterns, and the urbanization of each city together influence the spatial–temporal changes in the spatial morphology, offering references to policy making, planning, and construction to protect the regional characteristics in the future.     

氢氧化镁有机化改性研究

采用甲基丙烯酸甲酯为改性剂改性氢氧化镁,研究了引发体系的选择、复合乳化剂的用量、MMA与Mg(OH)2的用量、反应温度对吸油值的影响。结果表明,以过氧化苯甲酰为引发剂、复合乳液用量为1.5 g/L、MMA/Mg(OH)2为7/3~6/4、反应时间为3 h、反应温度为70℃时,改性Mg(OH)2吸油值最小,为31%。并对最佳条件下改性样品进行了扫描电镜表征。     

振幅调控双曲余弦高斯涡旋光束的聚焦特性

研究了双曲余弦高斯涡旋光束不同振幅参量对光场分布的影响。在相同光涡旋的情况下改变振幅的大小,在焦平面上场强分布变化明显。涡旋光束的拓扑数对光束的聚焦特性存在明显影响,不同的拓扑数会引起聚焦区域光强分布变化,另外也产生一些新的多焦点阵列和多重菱形聚焦图案。     

蒸压纤维水泥板覆面轻钢龙骨式复合墙体抗剪性能试验研究

为研究采用蒸压无石棉纤维素纤维水泥板(CCA板)覆面的轻钢龙骨式复合墙体的抗剪性能,进行了13片足尺墙体的水平单调加载和低周反复加载试验。试验结果表明,采用CCA板覆面轻钢龙骨式复合墙体的破坏主要表现为自攻螺钉连接处的CCA板拉裂或者螺钉拔出,最终CCA板失去传递剪力的能力而破坏,轻钢龙骨未发生明显破坏。基于试验结果,得到了各类CCA板覆面墙体的屈服荷载、最大荷载、破坏荷载以及位移延性系数等性能指标。最后,分析了CCA板厚度、密度以及加载方式对轻钢龙骨式复合墙体受剪性能的影响,并与OSB板、石膏板覆面墙体进行了比较。     

轻钢龙骨式结构工业化建筑体系

详细介绍了轻钢龙骨式建筑的结构体系组成,对其工业化建筑体系的优点进行了分析,进一步分析了应用推广需要解决的关键技术,指出了其可能成为我国工业化建筑的重要形式之一。