国外聚甲醛生产技术现状与发展

综述了国外主要甲醛生产厂商的工艺技术，树脂生产技术的发展和品种开发情况。     

从铁镜公主的扮相看旗装的发展变化

此文以京剧戏衣中的"旗装"为例,探讨了它演变的过程和演变背后的契因,目的在于通过服饰--这种无声的戏曲发展史--反思了京剧的审美进程,也辉映出其在20世纪--京剧真正意义的黄金时代--的发展历程.     

制造任务分解与制造单元级资源配置协同优化

针对网络化制造环境下制造任务分解与资源配置脱节的问题,提出了制造任务逐层分解与制造单元级资源配置协同优化的方法,建立了协同优化流程.在对制造任务特点进行分析的基础上,建立了制造任务模型和制造单元资源模型,建立了多目标优化模型和目标的综合评价体系,利用在遗传算法求解搜索过程中所获得的动态信息进行综合评价,并随着求解搜索过程的深入对变异幅度进行调整,以达到全局优化和加快收敛速度的目的.最后以实例验证了该方法的可行性与有效性.     

储罐地震易损性数值仿真分析

为了研究储罐的抗震性能,忽略储罐罐壁的质量,将储罐中的液体质量简化为三质点体系模型,地基土由两个弹簧和两个阻尼器模拟.考虑罐体的平动和转动,建立了在水平地震激励下储罐的动力方程;给出了随机变量的概率模型和基于易损性理论的失效概率计算方法.通过对大庆某油库2×104 m3和5×104m3两种大型储罐进行数值仿真方法的地震易损性分析.结果表明:随着地震烈度的增大,储罐的易损性逐渐增大;5×104 m3储罐的抗震性能要好于2×104 m3储罐;2×104 m3和5×104 m3储罐的主要失效模式分别是抗失稳和抗提离.由此可见从多个失效模式对储罐进行地震易损性研究比从单一失效模式进行易损性研究更加科学.     

An NMR study of the dissociation of N,N′-(2-propyloximino)-4,4′-methylenebis(phenylcarbamate) and its crosslinking of polymers containing labile hydrogens. II

Nuclear magnetic resonance spectroscopy has been used to study the dissociation and reaction of N,N′-(2-propyloximino)-4,4′-methylenebis(phenylcarbamate), as a crosslinking agent for polymers containing labile hydrogens. The crosslinking of poly(acrylic acid), polyacrylamide, and poly(vinyl alcohol) was found to result upon heating each to 150°C for 10 min with this component at 2–10 wt %.     

专用粉末涂料和涂装发展的新展望

新型专用粉末涂料以其涂膜超薄型化、低温固化和高耐候性等优势,并以预裁割坯料新工艺代替预涂装卷材工艺的新特点,将成为粉末涂料新的增长点。还提出了若干建议和意见。     

Fluorescence of poly(di-n-alkylsilane)s in room-temperature solution

A comprehensive study of the electronic absorption and emission spectra and the fluorescence quantum yield and lifetime of seven poly(di-n-alkylsilane)s and of three isotopically labelled poly(di-n-hexylsilane)s in hydrocarbon solution at room temperature is reported. Also reported are fluorescence polarization and carbon tetrachloride quenching of fluorescence of poly(di-n-hexylsilane). The observed fluorescence spectra, quantum yield, and polarization depend on the selected excitation energy in a very characteristic fashion, whereas the fluorescence lifetime does not; however, it depends on the selected emission energy. These characteristic dependencies are qualitatively accounted for by the previously proposed segment distribution model if one assumes that the photophysical behavior at higher excitation energies is strongly affected by the presence of a low-lying weakly allowed state in short-segment chromophores and the behavior at lower excitation energies is dictated by the selective excitation of emitting long-segment chromophores.     

Infrared reflectance and transmission spectra of semiconducting non-stoichiometric CdGe x As2

The infrared reflectance and transmission spectra of amorphous CdGe _x As₂ were investigated to study the amorphous structure with varying Ge content. The mid-infrared optical absorption edges of amorphous CdGe _x As₂ with 0<x<1.2, were observed in the range 1.6–1.7 m, indicating a structural similarity in short-range order throughout. Comparing the reflectance and transmission spectra of amorphous and devitrified crystalline phases established that the structures of amorphous CdGe _x As₂ transformed from the CdAs₂ basic structure to the chalcopyrite (CdGeAs₂) structure, as one progressed fromx=0 tox=1.2. The infrared spectra were interpreted interactively with radial distribution function, magnetic susceptibility, density measurements, and crystallization studies. The crystallization behaviour of amorphous CdGe _x As₂ that was heat treated at different temperatures was investigated using far-infrared transmission spectra.     

Image super-resolution using supervised multi-scale feature extraction network

Multimedia Tools and Applications - Image super-resolution using deep convolutional networks have recently achieved great successes. However, previous studies have failed to consider the spatial...     

Study of UAV tracking based on CNN in noisy environment

Multimedia Tools and Applications - Recently, there are lots of tracking methods proposed to improve the performance of visual tracking in videos with challenging situations, such as background...