仿生蜘蛛丝微纳米复合材料的集水性能

水是自然界大多数生物生存的必要条件,而动植物界存在着诸多奇妙的浸润现象。仿生微纳米复合材料浸润性相关研究是近年来国内外发展迅速的前沿热点,涉及跨领域、交叉领域。本文对仿生工程领域拥有集水性能的类蜘蛛丝微纳米复合材料的研究进展进行了评述,简要分析了材料的微纳米复合结构及其控制浸润性/液滴行为的机制,总结了类蜘蛛丝微纳米复合材料及集成蜘蛛网的制备技术发展(包括提拉法、静电纺丝法、微流体技术、三维编织技术、3D打印技术等),展示了不同微纳米复合材料及相应集水性能。本文重点分析并对比了仿生蜘蛛丝微纳米复合材料的仿生结构设计、材料制备技术、集水性能等,并展望了拥有集水性能的微纳米复合材料在微流体芯片、天气预报、海水淡化、药物缓释、微反应器、能量储运与转换等多领域的进一步新兴、多功能化应用。     

天然铠甲高效防护的材料学机理

总结了天然铠甲材料的三种共性组织结构特征及其内在强韧化机理,归纳出三种典型的生物力学效应,包括梯度结构取向效应、原位结构再取向效应和多级"缝合"界面效应,并提出了相应的仿生材料结构优化设计原则.生物力学理论的完善和多种仿生结构的综合应用,有利于使用新型仿生材料更好地解决实际工程问题.     

结构仿生材料的研究进展

自然界中生物体的优异结构和特性给人类研究材料带来了灵感和启发.借鉴这些生物体的优秀结构特征是结构仿生材料的主要设计思想和方法.重点阐述了仿生增韧陶瓷材料、仿生粘附材料、仿生减阻材料、仿生减振材料和仿生系统应用在设计和制备方面的研究进展,并展望了结构仿生材料的发展前景,强调了多学科协作的重要性.     

交叠增韧仿生复合材料的研究进展

仿生设计方法为制备结构与功能一体化材料提供了重要的思路和途径,已成为各国研究的重点,贝壳的分层结构和高强韧性能仿生制造是其中较为典型的一类,据此可开发出具有优异的防护性能和抗裂纹扩展能力的层状复合材料。对层状复合材料制备工艺、界面扩散及结合强度、增韧机制、弹道防护性能的研究现状进行了简要综述,评价和总结了目前存在的问题,并对仿生制造的应用前景进行了展望,指出应加强层状复合材料变形的理论研究,进一步拓展层状复合材料的应用领域。     

从低维到高维的仿生材料制备及其应用进展

经过数十亿年的进化,自然界中的生物材料表现出许多卓越的性质和独特的功能。这些生物材料通常是由生物体内的有限组分在温和条件下组装而成,其优异的性能在很大程度上来源于复杂的多级结构,例如含邻苯二酚单元的贻贝粘附蛋白具有普适的强粘附力,珠-线结构的蜘蛛丝具有优异机械性能和集水能力,空心结构的北极熊毛发具有隔热保温作用,规则微纳结构的蝴蝶翅膀显示多彩的颜色,梯度多孔结构的柚子皮具有优异的阻尼减震效果等。以自然界的设计原理为灵感制造人工材料在材料科学和工程领域受到了极大关注,过去数10年,这方面的研究成果不胜枚举。总结了仿生材料在结构仿生方面的研究进展,选取了几个从低维到高维尺度上的典型例子概述了仿生材料的结构和功能之间的关系。     

仿生超疏水表面的制备与应用研究进展

近年来,人们受到自然界产生的超疏水现象的影响和启发,通过仿制生物表面结构制备出各种超疏水材料。超疏水材料因其表面独特的性质,在工业与军事领域得到了广泛应用。介绍了仿生超疏水材料表面的4种制备方法——模板法、溶胶-凝胶法、静电纺丝法和电沉积法,也涉及了其他制备方法,同时结合各种制备方法对仿生超疏水材料的最新研究成果进行了阐述。最后,总结了超疏水材料研究过程中存在的问题,并展望了其未来的发展方向。     

仿生结构材料的研究进展

综述了贝壳珍珠层、蛛丝结构、毛竹外密内疏结构、骨骼哑铃型结构、植物的根部网状结构以及木材的年轮结构等天然生物材料的结构特征及其相应的仿生材料近年来的研究进展；展望了结构仿生材料的前景，认为应对现有生物体的结构特征与其性能的相关性进行进一步的研究，并对已经解析的结构从不同的角度构筑模型，在实际应用中寻找模型和仿生材料设计的结合点，以推动仿生材料学的发展．     

可降解高分子聚合物在仿生骨膜中的应用进展

骨膜是骨骼生长的重要组成部分,覆盖在大多数骨骼的外表面,在骨缺损修复中起着中至关重要的作用。然而,由意外事故引起的骨折会引发骨膜的损伤,且由于自体骨膜和异体骨膜移植的免疫排斥反应、来源有限等问题使其在临床应用中受到极大的限制。因此,研究人员致力于开发一种与原生骨膜结构性能相似的仿生骨膜。文中综述了近年来可降解高分子聚合物在仿生骨膜中的研究进展,分别从仿生骨膜所用的可降解高分子聚合物材料、仿生骨膜的性能及制备方法3个方面进行综述,最后提出了一些当前的问题并进行了展望。     

仿生无机材料在石质文物保护中的应用

90年代,出现了一种模拟生物矿化中无机物在有机物调制下形成过程的合成技术-仿生合成.仿生无机材料是一种具有特殊化学和物理性能的新型材料,现已越来越广泛地应用于医学材料、纳米材料、薄膜材料和多孔材料等领域.由于仿生无机材料潜在广阔的应用空间,使得仿生合成无机材料技术成为材料化学研究的热点.本文介绍了仿生合成技术的基础理论和目前仿生无机材料的应用领域.分析了仿生无机材料在石质文物保护应用中的可行性及优越性,表明是一种很有潜力的新型保护材料.     

仿生与生物启发膜的研究进展

仿生与生物启发的思想和策略在众多基础与工程科学领域取得了重要进展。研究者们通过借鉴和模仿自然界中生物材料多样的组成、精巧的结构、温和的形成过程以及强大的功能,设计制备了多种高性能膜材料,并将其应用于水处理、气体分离、有机小分子液体混合物分离等领域,显示出良好的应用前景。仿生和生物启发膜主要是以细胞膜、荷叶和贻贝等为仿生原型,以生物矿化、生物黏合和自组装等为工具,以绿色、高效、节能为目标,在资源、能源高效利用和可持续发展等方面会发挥越来越大的作用,并逐步发展成为膜和膜过程领域的重要分支。本文将对仿生和生物启发膜的研究进展进行简要总结,重点介绍抗污染膜、杂化膜和复合膜的制备与应用。     

An unusual superhydrophilic/superoleophobic sponge for oil--water separation

Development of porous materials with anti-fouling and remote control- lability is highly desired for oil–water separation application yet still challenging. Herein, to address this challenge, a sponge with unusual superhydrophilicity/superoleophobicity and magnetic property was fabricated through a dip-coating process. To exploit its superhydrophilic/superoleophobic property, the obtained sponge was used as a reusable water sorbent scaffold to collect water from bulk oils without absorbing any oil. Owing to its magnetic property, the sponge was manipulated remotely by a magnet without touching it directly during the whole water collection process, which could potentially lower the cost of the water collection process. Apart from acting as a water-absorbing material, the sponge can also be used as affiliation material to separate water from oil–water mixture and oil in water emulsion selectively, when fixed into a cone funnel. This research provides a key addition to the field of oil–water separation materials.     

Fog water as an alternative and sustainable water resource

As the world’s population and demand for fresh water increases, new water resources are needed. One commonly overlooked aspect of the water cycle is fog, which is an important part of the hydrology of coastal, high-altitude, and forested regions. Fog water harvesting is being investigated as a sustainable alternative water resource for drinking water and reforestation. Fog water harvesting involves using mesh nets to collect water as fog passes through them. The materials of these nets, along with environmental factors such as wind speed, influence the volume of water collected. In this article, a review of current models for fog collection, designs, and applications of fog water harvesting is provided. Aspects of fog water harvesting requiring further research and development are identified. In regions with frequent fog events, fog water harvesting is a sustainable drinking water resource for rural communities with low per capita water usage. However, an analysis of fog water harvesting potential for the coastal areas of northern California (USA) showed that fog yields are too small for use as domestic water in areas with higher household water demands. Fog water shows particular promise for application in reforestation. Fog water irrigation can increase growth rates and survivability of saplings in reforestation efforts in regions with frequent fog events. Using fog collectors, denuded areas once dependent on natural fog drip can be restored, benefiting local hydrology and ecosystem recovery. Improvement in fog collector designs, materials, and models to increase collection efficiency, perhaps by inclusion of ideas from natural systems, will expand the regions where fog harvesting can be applied.     

Ultrasonic collection of small particles by a tapered metal strip

A pi-shaped ultrasonic actuator can collect small particles by its two sharp edges. However, the collection of particles is weak in air and not very stable in water. In this paper, a refinement to the pi-shaped ultrasonic actuator is made for a more efficient collection of small particles in air and water. In the refined structure, an ultrasonic actuator with a metal strip is used to collect small particles. The metal strip is mechanically driven by one corner of a rectangular, sandwich-shaped ultrasonic transducer operating in the thickness mode vibration. The metal strip is tapered along its length and has a strong vibration at its tip. Small particles in air and water can be attracted to the radiation surface near the end of the metal strip. The dependence of the number of collected particles on driving frequency and voltage is investigated for shrimp eggs, mint seeds, and grass seeds. For a given driving voltage and particle type, the number of collected particles reaches a maximum value at some driving frequency. Increasing driving voltage increases this maximum number to some extent; but too large a driving voltage decreases it. The maximum number also depends on the weight per particle. It increases as the weight per particle decreases for the particles with close densities. Furthermore, the relationship between the number of collected particles and vibration amplitude at the end of the metal strip is investigated for shrimp eggs, mint seeds, and grass seeds. The number is approximately linearly proportional to the vibration amplitude when the vibration amplitude is not too large. In addition to the application in which the length of the metal strip is parallel to gravitation, the actuator also can be used with its length perpendicular to gravitation. However, the latter has a weaker capability of collecting small particles. It is also found that the actuator has a stronger capability to collect particles in water than in air.     

Planning for hazardous campus waste collection

This study examines a procedure developed for planning a nation-wide hazardous campus waste (HCW) collection system. Alternative HCW plans were designed for different collection frequencies, truckloads, storage limits, and also for establishing an additional transfer station. Two clustering methods were applied to group adjacent campuses into clusters based on their locations, HCW quantities, the type of vehicles used and collection frequencies. Transportation risk, storage risk, and collection cost are the major criteria used to evaluate the feasibility of each alternative. Transportation risk is determined based on the accident rates for each road type and collection distance, while storage risk is calculated by estimating the annual average HCW quantity stored on campus. Alternatives with large trucks can reduce both transportation risk and collection cost, but their storage risks would be significantly increased. Alternatives that collect neighboring campuses simultaneously can effectively reduce storage risks as well as collection cost if the minimum quantity to collect for each group of neighboring campuses can be properly set. The three transfer station alternatives evaluated for northern Taiwan are cost effective and involve significantly lower transportation risk. The procedure proposed is expected to facilitate decision making and to support analyses for formulating a proper nation-wide HCW collection plan.     

Excellent Fog‐Droplets Collector via Integrative Janus Membrane and Conical Spine with Micro/Nanostructures

Inspired by a cactus spine and trichomes integrated fog collection system, a strategy is presented to design a micro/nanostructured conical spine and Janus membrane integrative system (MNCS+JM). In this strategy, the surface of conical spine can be covered with rough micro and nanostructure (MNCS), so that the tiny fog‐droplets can be captured, coalesced, and transported. Janus membrane (JM) with inside hydrophobic surface and outside hydrophilic surface is further used to control the water collection in process of droplet transport when the Janus membrane is vertically placed with different positions on the MNCS, thus MNCS+JM propel the droplet continuously for transport–coalescence–transport in a circle of droplet transport and collection. It is demonstrated that a higher fog collection rate can be achieved effectively, which is attributed to a cooperation effect between the Laplace pressure in difference and the released surface energy in droplet coalescence, in addition to wettability force of superhydrophobic–hydrophilic difference in the Janus membrane. This strategy of MNCS+JM offers an insight into the surface of materials to control the droplet transport for water collection in efficiency, which is significant to be extended into the realms of applications such as high‐efficiency water collection systems, microfluidics devices, and others.     

Portable Low‐Pressure Solar Steaming‐Collection Unisystem with Polypyrrole Origamis

Solar steaming has emerged as a promising green technology that can address the global issue of scarcity of clean water. However, developing high‐performance, cost‐effective, and manufacturable solar‐steaming materials, and portable solar steaming‐collection systems for individuals remains a great challenge. Here, a one‐step, low‐cost, and mass‐producible synthesis of polypyrrole (PPy) origami‐based photothermal materials, and an original portable low‐pressure controlled solar steaming‐collection unisystem, offering synergetic high rates in both water evaporation and steam collection, are reported. Due to enhanced areas for vapor dissipation, the PPy origami improves the water evaporation rate by at least 71% to 2.12 kg m^?2 h^?1 from that of a planar structure and exhibits a solar–thermal energy conversion efficiency of 91.5% under 1 Sun. When further controlling the pressure to ≈0.17 atm in the steaming‐collection unisystem, the water collection rate improves by up to 52% systematically and dramatically. Although partial energy is utilized toward obtaining low‐pressure, evaluations show that the overall energy efficiency is improved remarkably in the low‐pressure system compared to that in ambient pressure. Furthermore, the device demonstrates effective decontamination of heavy metals, bacteria, and desalination. This work can inspire new paradigms toward developing high‐performance solar steaming technologies for individuals and households.     

Precise Manipulation and Patterning of Protein Crystals for Macromolecular Crystallography Using Surface Acoustic Waves

Advances in modern X‐ray sources and detector technology have made it possible for crystallographers to collect usable data on crystals of only a few micrometers or less in size. Despite these developments, sample handling techniques have significantly lagged behind and often prevent the full realization of current beamline capabilities. In order to address this shortcoming, a surface acoustic wave‐based method for manipulating and patterning crystals is developed. This method, which does not damage the fragile protein crystals, can precisely manipulate and pattern micrometer and submicrometer‐sized crystals for data collection and screening. The technique is robust, inexpensive, and easy to implement. This method not only promises to significantly increase efficiency and throughput of both conventional and serial crystallography experiments, but will also make it possible to collect data on samples that were previously intractable.     

全自动废水坐便器的设计

从水资源开发保护成本及其使用的经济性角度出发,介绍一种全自动废水坐便器,着重阐述了其工作原理和内部结构特点.该坐便器的冲洗功能、节水效率、环保性、可靠性和使用寿命等性能指标均超过目前的节水坐便器,而自动化程度和方便使用等方面已达到国际领先水平.其自动化特征表现为:冲便时自动优先选择废水;若废水不足时,自动补充"最低需要量"的自来水;废水回收装置自动保持"最大废水存储容量";自动识别废水量,并据此自动选择排水水箱;自动收集废水.应用结果表明,该坐便器自动化程度高、性价比高、可靠性好、使用灵活方便,具有广阔的应用前景.     

Materials and design of solar heating systems for domestic hot water

Solar heating systems for domestic hot water in moderate climates such as the U.K. are only marginally cost-effective over their life-times. As such, the cost of durable high quality materials must be balanced by long-lasting efficient collection of energy, which is provided by optimising design and careful selection of materials.     

远程心音采集识别系统的研发

为实现心音的采集与远程传输,完成远程心音采集识别系统整体方案设计。采集终端基于LPC2214搭建硬件平台,设计液晶模块OCM240128-7和网络控制芯片RTL8019AS等接口电路,实现心音采集、存储、传输和查询等功能。服务器软件基于Visual studio 2005平台开发,采用Windows Socket实现网络通信,调用SQL Server实现数据的管理。