Controllable Dynamic Zigzag Pattern Formation in a Soft Helical Superstructure

Zigzag pattern formation is a common and important phenomenon in nature serving a multitude of purposes. For example, the zigzag‐shaped edge of green leaves boosts the transportation and absorption of nutrients. However, the elucidation of this complicated shape formation is challenging in fluid mechanics and soft condensed matter systems. Herein, a dynamically reconfigurable zigzag pattern deformation of a soft helical superstructure is demonstrated in a photoresponsive self‐organized cholesteric liquid crystal superstructure under the simultaneous influence of an applied electric field and light irradiation. The zigzag‐shaped pattern can not only be generated and terminated repeatedly on demand, but can also be easily manipulated by alternating irradiation of ultraviolet and visible light while under the influence of a sustained electric field. This unique behavior results from a delicate balance among the variable experimental parameters. The evolution of the zigzag‐shaped pattern is successfully modeled by numerical simulations and has been monitored through diffraction of a probe laser. Interestingly, this fascinating zigzag‐shaped pattern yields crescent‐shaped diffraction pattern. The reversibly controllable dynamic zigzag pattern could enable the fabrication of novel photonic devices and architectures, besides greatly advancing the fundamental understanding of temporal behavior of ordered soft materials under combined stimuli.     

基础隔震建筑的滑模控制

基于滑模控制理论,提出了地震激励下含有不确定性参数的隔震建筑结构的滑模控制方法。通过优化极点配置,设计了鲁棒滑面和相应的滑模控制器。算例控制模拟的结果表明,该控制方法能有效抑制具有不确定参数的结构响应,受限控制的效果也较好。     

论书籍形态设计要素的创新与发展

书籍是人类表思传知、积累文化的重要载体.书籍形态设计也伴随时代的进步不断发展.分析了书籍形态设计发展演变的进程,并提出了未来书籍设计师的责任,对今后书籍设计发展有一定的意义.     

Metrological Assurance as a Base for Building a Quality System

We consider the role of metrological assurance of quality systems in the initial stage of development, based on the ISO 9000 standards. Most of the quality system elements must be developed with account for the requirements of the standardizing documents for metrological assurance of production. The body of actual standardizing documents of the state measurement traceability system given is expedient for use when developing company quality systems.     

Measurement of the Properties of a Plasma Column Used as a Radiating Element

This paper presents two test benches for the characterization of a plasma column used as a radiating element. In particular, the main parameters to be quantified are the efficiency of the plasma antenna, the turn-on time of the column, and the conductivity of the plasma. The first two parameters are evaluated by measuring the field radiated by the plasma antenna compared with that of an equivalent copper antenna. For the conductivity, a reflectometric technique is used, wherein the plasma column is inserted inside a waveguide. The accuracy of the method is limited by the ill-conditioned relationship between the reflection coefficient and the plasma conductivity; nevertheless, it is sufficient to subdivide the range of the conductivity values into three regions (i.e., low, medium, and high conductivities) to determine the best operating conditions of the antenna.     

包装企业构建绿色管理模式的研究

高价资源、能源和高环保条件下的中国包装企业必须走绿色之路,才能实现其可持续发展,而绿色管理是实现这一目标的根本保证.绿色管理的有效性取决于企业绿色管理模式的构建,文章分析了包装企业绿色管理模式的内容,探讨了构建方法.     

Formation of Sets of Independent Components of a Multidimensional Random Variable Based on a Nonparametric Pattern Recognition Algorithm

Measurement Techniques - We consider the possibility of circumventing the decomposition problem for the range of values of random variables when testing various hypotheses. A brief review of the...     

Glycogen as a Building Block for Advanced Biological Materials

Biological nanoparticles found in living systems possess distinct molecular architectures and diverse functions. Glycogen is a unique biological polysaccharide nanoparticle fabricated by nature through a bottom-up approach. The biocatalytic synthesis of glycogen has evolved over time to form a nanometer-sized dendrimer-like structure (20–150 nm) with a highly branched surface and a dense core. This makes glycogen markedly different from other natural linear or branched polysaccharides and particularly attractive as a platform for biomedical applications. Glycogen is inherently biodegradable, nontoxic, and can be functionalized with diverse surface and internal motifs for enhanced biofunctional properties. Recently, there has been growing interest in glycogen as a natural alternative to synthetic polymers and nanoparticles in a range of applications. Herein, the recent literature on glycogen in the material-based sciences, including its use as a constituent in biodegradable hydrogels and fibers, drug delivery vectors, tumor targeting and penetrating nanoparticles, immunomodulators, vaccine adjuvants, and contrast agents, is reviewed. The various methods of chemical functionalization and physical assembly of glycogen nanoparticles into multicomponent nanodevices, which advance glycogen toward a functional therapeutic nanoparticle from nature and back again, are discussed in detail.     

基于眼动技术的牡丹纹样意象元素识别方法研究

目的 针对目前传统文化意象和现代产品设计之间匹配关系模糊、意象风格难以统一的问题,通过识别传统纹样中表征意象的图像元素,将其应用并服务于现代设计行业.方法 以宋代牡丹纹样的描述词汇为样本,采用多维尺度法归纳出意象维度,根据语义差异法完成对纹样的意象分类;基于眼动跟踪技术得到各意象维度下的注视数据,采用均值漂移算法聚类出具有意象代表性的纹样元素并量化其表征度.结果 得到高雅、祥瑞、素雅、柔润、灵动和精致6个意象维度下的纹样意象元素,并计算得出代表该意象元素在牡丹纹样意象中的贡献程度指标——表征度.结论 实验表明该方法具有可重复性和可行性,识别结果表现出了一定的意象内涵和应用价值,可为传统文化再设计提供参考思路.     

反应准备方式对空间线索作用的影响

采崩反应线索范式，分别探讨了在线索准备反应位置和线索准备反应器条件下的线索效应模式。结果发现：①在双手自然放置时，反应准备方式对线索效应模式没有显著影响。②在双手非自然放置时，当线索准备反应器时，左右手的编码作为反应的空间参照系对于左右线索的加工起到了显著的促进作用；但当线索准备反应位置时，左右手的空间参照作用不显著。     

Finite Element Analysis as a Method to Study Molluscan Shell Mechanics

The clade Mollusca is a highly diverse and disparate group of terrestrial and aquatic invertebrates, the taxon containing over 100 000 known species including some of the most intelligent invertebrate animals. Their shells are exemplar systems in the study of biomechanics, biomineralization, and biomimetics. Research into understanding the superior biomechanical properties of the shell and how these properties relate to the animals ecology have required a diverse range of methods at multiple length scales; one particularly powerful method is finite element analysis. Finite element analysis is a robust engineering method that has a long‐standing history in biomechanical research. This review summarizes the application of finite element analysis in the study of both the mechanical properties of different molluscan shell ultrastructures as well as macro‐scale modeling of the shell. From the calculation of elastic constants to the origins of the strength of nacre and the relationship between shell folding and ecology, this article provides a window into how finite element analysis can further our understanding of mechanics and functional morphology.

     

Formation of a layer of a liquid as it impinges on a horizontal plane

We have conducted a numerical study of the spreading out of a liquid over a horizontal plane, with the liquid, in this case, running off over the surface of a semiinfinite vertical cylinder.Translated from Inzhenerno-Fizicheskii Zhurnal, Vol. 57, No. 6, pp. 896–600, December, 1989.     

有限—离散杂交元岩石爆破漏斗数值模拟研究

为了验证有限—离散杂交元模拟岩石爆破结果的真实性、可靠性,对岩石爆破漏斗产生过程进行了数值模拟。采用联合单一与弥散裂纹模型实现从有限元模拟到离散元模拟的转化,应用等截面管道模型模拟爆破气体对裂缝的扩张作用。模拟结果表明:有限—离散杂交元能够模拟出岩石爆破中应力波的产生、传播及在自由面反射的整个过程,能够再现岩石破碎的产生、裂隙的扩展及碎石的抛掷过程。模拟出的岩石爆破的主要分区,即破碎区、裂隙区、和弹性区,与理论研究相符,监测点的应力时程曲线与文献中的结果具用相同特征。因此有限—离散杂交元能够模拟出爆破漏斗产生的整个动态过程,为岩石爆破理论的研究提供了新的手段。     

纳米铝液的转移方式对图案自动成型效果的模拟

目的 研究利用选择性吸附原理实现纳米图案自动成型的可行性,以及转移方式对自动成型效果的影响。方法 通过分子动力学方法分别研究块体铝和两纳米铝团簇的加热升温过程,得到纳米铝液势能–温度变化曲线,并确定纳米铝液图案自动成型的模拟温度;利用LAMMPS软件建立图案自动成型所需的印版模型;分别以液膜转印和液滴喷印的方式,研究纳米铝液在石墨烯–铜基印版表面上润湿铺展情况。结果 纳米铝液能够在石墨烯–铜基印版表面实现图案自动成型;液膜模型和液滴模型的图案自动成型效果不同,液膜较薄时（双层铝原子）模拟时间为1 200 ps时,整个体系达到动态平衡状态,图案区的铝液厚度约为1.8 nm,图案自动成型效果较好;当液膜较厚时（三层铝原子）,模拟时间为1 200 ps时,整个体系达到动态平衡状态,但图案区的两线条间存在较多铝原子残留,自动成型效果较差;而2种液滴模型均实现了较好的图案成型效果,液滴数量为4滴时,模拟时间为3 000 ps时可形成厚度均匀的图案,当液滴数量为6滴时,模拟运行600 ps时图案区即可形成的稳定均匀的线条。结论 利用选择性吸附原理可实现纳米图案自动成型,成型效果受铝液转移方式的影响...     

Formation of novel thermoplastic composites using bicomponent nonwovens as a precursor

This study focuses on a novel technique to produce thermoplastic composites directly from bicomponent nonwovens without using any resins or binders. Conceptually, the structure of the bicomponent fibers making up these nonwovens already mimics the fiber–matrix structure of fiber reinforced composites. Using this approach, we successfully produced isotropic thermoplastic composites with polymer combinations of polyethylene terephthalate/polyethylene (PET/PE), polyamide-6/polyethylene (PA6/PE), polyamide-6/polypropylene (PA6/PP), and PP/PE. The effects of processing temperature, fiber volume fraction, and thickness of the preform on the formation and structure of the nonwoven composites were discussed. Processing temperatures of 130 and 165 °C for PE and PP matrices, respectively, resulted in intact composite structures with fewer defects, for fiber volume fraction values of up to 51%. Moreover, an insight into the changes on the fine structure of the bicomponent fibers after processing was provided to better explain the mechanics behind the process. It is hypothesized that the composite fabrication process can result in annealing and increases the degree of crystallinity and melting temperature of polymers by thickening lamellae and/or removing imperfections. One of the other outcomes of this study is to establish what combination of mechanical properties (tensile and impact) nonwoven composites can offer. Our results showed that compared to glass mat reinforced thermoplastic composites, these novel isotropic nonwoven composites offer high specific strength (97 MPa/g cm⁻³ for PA6/PE), very high strain to failure (152% for PP/PE), and superior impact strength (147 kJ/m² for PA6/PP) which can be desirable in many critical applications.     

建筑火灾中远程交互模式对寻路绩效的影响

火灾搜救团队在高层建筑火灾中信息交互手段受限且缺乏理论支持。本文根据空间信息的传递方式选取3种交互模式：1） 语音;2） 建筑平面图及规范语音;3） 视频。实地模拟高层建筑火场进行实验,记录并分析参试者逃生时间与路程。结果表明,在语言沟通方式下,逃生时间与逃生所走的总距离最长。在建筑平面图及语音沟通方式下,逃生时间与逃生所走的总距离最短。在动态环境下,建筑平面图及规范语音的交互模式使得寻路更高效且更准确。     

生成项模型在二氧化钛颗粒合成中的应用

为了更好地研究二氧化钛纳米颗粒合成过程中生成项模型以及表面氧化反应对颗粒尺寸的影响,用CFD商业软件Fluent,对湍流扩散火焰中的颗粒合成过程进行了详细的数值模拟。在没有通入TiCl4先驱物的情况下,计算出火焰的温度场。然后通过对五种不同工况的对比,讨论了火焰场温度和浓度对颗粒生长的影响。在此基础上考虑了表面氧化反应对颗粒尺寸变化的影响。结果表明：表面氧化反应对颗粒尺寸的分布具有一定影响,但是温度才是颗粒尺寸变化的最主要影响因素。