Fibrillar Elastomeric Micropatterns Create Tunable Adhesion Even to Rough Surfaces

Biologically inspired, fibrillar dry adhesives continue to attract much attention as they are instrumental for emerging applications and technologies. To date, the adhesion of micropatterned gecko‐inspired surfaces has predominantly been tested on stiff, smooth substrates. However, all natural and almost all artificial surfaces have roughnesses on one or more different length scales. In the present approach, micropillar‐patterned PDMS surfaces with superior adhesion to glass substrates with different roughnesses are designed and analyzed. The results reveal for the first time adhesive and nonadhesive states depending on the micropillar geometry relative to the surface roughness profile. The data obtained further demonstrate that, in the adhesive regime, fibrillar gecko‐inspired adhesive structures can be used with advantage on rough surfaces; this finding may open up new applications in the fields of robotics, biomedicine, and space exploration.     

Model Organic Surfaces to Probe Marine Bacterial Adhesion Kinetics by Surface Plasmon Resonance

Understanding how bacteria adhere to a surface is a critical step in the development of novel materials and coatings to prevent bacteria forming biofilms. Here, surface plasmon resonance (SPR) spectroscopy, in combination with self‐assembled monolayers (SAMs) that have different backbone structures and/or functional groups, is used for the first time to study the initial stages of bacterial adhesion to surfaces (i.e., initial interaction of cells with a surface, a process governed by van der Waals, electrostatic, and hydrophobic interactions). The work highlights SPR spectroscopy as a powerful and unique approach to probe bacterial adhesion in real time. SPR spectral data reveal different kinetics of adhesion for the interaction of two marine bacterial species (Marinobacter hydrocarbonoclasticus and Cobetia marina) to a range of organosulfur SAMs. Furthermore, the extent of adhesion is dependent on the backbone structures and functional groups of the SAMs. The role of extracellular polymeric substances (EPS) in bacterial adhesion is also investigated. Pre‐conditioning experiments with cell‐free culture supernatants, containing planktonic EPS, allow quantification of the amount adsorbed onto surfaces and directly account for the impact of EPS adsorption on bacterial adhesion in the assay. While the physicochemical characteristics of the surfaces play a significant role in determining bacterial cell adhesion for low levels of conditioning by planktonic EPS, greater levels of conditioning by EPS reduce the difference between surfaces.     

应用激光侧向散射测量粒径分布的理论研究

提出一种新型的颗粒测量方法，基于Ｍｉｅ散射理论，从另一独特的视角接收大角度的侧向散射光，并建立新的理论模型，可使测量下限扩展，技术要求有所改善。结合目前已经成熟的半导体激光和ＣＣＤ技术，运用此原理可使颗粒测量仪器向更轻便、灵敏发展     

Skin-Inspired Nanofluid-Filled Surfaces with Tunable Icephobic,Photothermal, and Energy Absorption Properties

Ice buildup can significantly and negatively impact system performance in various industrial sectors, and has remained a persistent challenge for decades. Many compliant materials exhibit excellent de-icing performance but are easily eroded by impacts from supercooled water droplets, sand, dust, and debris. A composite panel inspired by animal skin, consisting of a facesheet protecting a nanofluid layer beneath, which exhibits durable anti-icing and tunable photothermal properties is proposed. The viscous liquid layer beneath the facesheet increases flexural rigidity, preventing large deflections and increasing deformation resistance, which alters ice's adhesion to the surface. The non-uniform fluid pressure exerted by the viscous nanofluid-filled composite panels facilitates ice detachment, resulting in ice adhesion strengths as low as τ_ice ≈ 10 kPa. Further, by altering the fluid properties, different additional functionalities can be endowed to the system. Incorporating fumed silica in a fluid-filled composite panel results in rheopectic behavior, and this doubles their impact resistance when the shear thickening properties are properly tuned. Additionally, the combination of a transparent facesheet and a solar light absorbent nanofluid allows for tunable photothermal properties, further enhancing the anti-icing performance of the system. This durable and tunable nanofluid-filled composite panel shows great promise as a multifunctional de-icing material.     

Macrophage Hitchhiking Nanoparticles for the Treatment of Myocardial Infarction: An In Vitro and In Vivo Study

Myocardial infarction (MI) is the leading cause of death worldwide. However, current therapies are unable to restore the function of the injured myocardium. Advanced approaches, such as stimulation of cardiomyocyte (CM) proliferation are promising, but suffer from poor pharmacokinetics and possible systemic adverse effects. Nanomedicines can be a solution to the above-mentioned drawbacks. However, targeting the cardiac tissue still represents a challenge. Herein, a MI-selective precision nanosystem is developed, that relies on the heart targeting properties of atrial natriuretic peptide (ANP) and lin-TT1 peptide-mediated hitchhiking on M2-like macrophages. The system based on pH-responsive putrescine-modified acetalated dextran (Putre-AcDEX) nanoparticles, shows biocompatibility with cultured cardiac cells, and ANP receptor-dependent interaction with CMs. Moreover, treatment with nanoparticles (NPs) loaded with two pleiotropic cellular self-renewal promoting compounds, CHIR99021 and SB203580, induces a 4-fold increase in bromodeoxyuridine (BrdU) incorporation in primary cardiomyocytes compared to control. In vivo studies confirm that M2-like macrophages targeting by lin-TT1 peptide enhances the heart targeting of ANP. In addition, NP administration does not alter the immunological profile of blood and spleen, showing the short-term safety of the developed system in vivo. Overall, the study results in the development of a peptide-guided precision nanosystem for delivery of therapeutic compounds to the infarcted heart.     

超声雾化频率与雾化粒径关系的实验研究

研究建立了超声雾化装置,使用不同频率的压电换能器对抑尘剂进行了雾化,利用welas 2000气溶胶粒径谱仪对雾化产生的雾滴粒径进行了测定。结果表明,相同雾化条件下,雾滴粒径随压电换能器的振动频率增大而减小,减小量与理论计算具有较好的相合性。     

Bioinspired Directional Surfaces for Adhesion,Wetting, and Transport

In Nature, directional surfaces on insect cuticle, animal fur, bird feathers, and plant leaves are composed of dual micro‐nanoscale features that tune roughness and surface energy. Here, experimental and theoretical approaches for the design, synthesis, and characterization of new bioinspired surfaces demonstrating unidirectional surface properties are summarized. The experimental approaches focus on bottom‐up and top‐down synthesis methods of unidirectional micro‐ and nanoscale films to explore and characterize their anomalous features. The theoretical component focuses on computational tools to predict the physicochemical properties of unidirectional surfaces.     

UPF算法及其在目标跟踪中的应用

分析了基于贝叶斯理论的粒子滤波算法的优缺点,研究了一种改进的粒子滤波(PF)算法UPF。将两种算法在目标跟踪中的性能进行了比较。仿真结果表明,改进算法UPF定位精度更高,抗噪声能力更强,实时性更好。     

烟雾浓度及粒径的激光探测实验研究

烟雾是火灾的前兆和伴随产物,是火灾过程中的重要物理现象。烟雾浓度和平均粒径是烟雾的两个重要特性参数,是早期火灾探测的基础。本文对激光与烟雾相互作用进行了具体分析,提出了一种基于激光消光法和角散射法,同时探测烟雾的浓度和平均粒径的方法。本方法可用来进行早期火灾的探测报警,能克服传统的光电感烟探测技术存在的缺点,大大提高火灾探测的可靠性和灵敏度。     

烟幕粒子粒度的分形特征及红外消光性能研究

以分形理论为基础,提出了一种表征烟幕粒子粒度特征的指标——粒度分形维数(D),研究了烟幕粒子粒度的分形特征.研究表明,烟幕粒子的粒度分布是分形的,烟幕中大颗粒占的比例越高,粒度分形维数越小,基于米氏理论的红外消光性能也越好.粒度分形维数(D)可用于表征烟幕粒子粒度分布的特征,为烟幕系统的研究提供了一种新思路.     

基于DirectDraw及粒子系统的飞机水汽尾迹仿真算法研究

利用粒子系统的基本原理,将飞机水汽尾迹定义为一系列具有生命周期的不规则、随机分布的粒子,给出相应的动力学模型和算法,实现飞机水汽尾迹的仿真.针对仿真过程中色彩转换相对困难的问题,采用查询预先存储的RGB颜色分量的各级强度值的方式,结合DirectDraw的换页技术,加快了算法的运行速度.     

纺织厂粉尘净化效率及粒径分布的实验研究

纺织厂在生产运作过程中产生大量的粉尘,这些种类不同的粉尘的粒径差别很大,对纺织厂的生产和人体的健康产生很大影响。对西安某纺织厂细纱车间粉尘浓度进行分析,细纱机工作区的空气粉尘浓度值几乎都在2.0 mg/m3以下,喷水室对粉尘的总净化效率为75%。运用专业粉尘颗粒物分析软件Ima ge-Pro Plus6.0研究粉尘粒径分布规律,得到含尘气流在经过喷水室前后粉尘数量分散度的变化;粒径>15μm的大颗粒粉尘的分级效率达到了83.5%,而粒径≤5μm的微粒分级效率为30.4%,说明喷水室对大颗粒粉尘除尘效果较好,加强对微细颗粒的去除是下一步研究的重点。     

具有量子行为的粒子群优化算法惯性权重研究及应用

在研究惯性权重对基本PSO算法影响的基础上,根据惯性权重对粒子群算法影响的特点,采用4种惯性权重策略对一种新的具有量子行为的粒子群算法的速度进行调节,比较每种算法的性能,从中找到一种新的性能更好的改进算法,将其用于求解0-1背包问题。实验结果表明较好地选择惯性权重参数对算法的性能有很大提高,该改进算法在求解0-1背包问题中具有高效性,提高了最优解的精度,同时具有较快的收敛速度。     

三结构各向同性包覆燃料颗粒相衬CT图像的噪声和伪像抑制方法初探

对三结构各向同性包覆燃料颗粒相衬CT图像的噪声和伪像抑制进行了初步探索,提出了三种方法分别抑制由探测器随机噪声、非线性漂移以及灵敏度非均匀性所导致的图像噪声或伪像.对抑制噪声或伪像前后的图像质量进行了主观评价以及定量分析,结果表明,本文提出的三种方法在有效抑制上述三种类型噪声或伪像的同时仍然能够保证重建图像中不同结构间边缘的清晰度.     

ULSI介质CMP用大粒径硅溶胶纳米研磨料的合成及应用研究

针对超大规模集成电路多层互连结构中介质CMP抛光速率低,急需的大粒径硅溶胶研磨料,本文采用改进的粒径生长控制工艺制备介质CMP用大粒径硅溶胶,并采用TEM、激光粒度分析仪和Zeta电位测试仪等先进手段对其粒径大小、粒径分布和稳定性进行了表征。以低分散度硅溶胶纳米研磨料配制抛光浆料进行了二氧化硅介质的CMP研究,结果表明,平均粒径103．4nm的硅溶胶浆料的去除速率达630nm／min,有效解决了二氧化硅介质CMP低速率的难题。     

Al2O3陶瓷上金刚石膜生长工艺优化及α粒子响应

采用微波等离子体化学气相沉积（MPCVD）法在氧化铝陶瓷衬底上沉积金刚石膜，并制作梳状电极的α粒子探测器．通过优化薄膜生长条件，发现酒精浓度为0.8%、沉积温度为850℃时，金刚石薄膜的介电常数最接近单晶金刚石膜，X射线衍射、喇曼光谱及扫描电子显微镜测试表明金刚石膜的质量较好.探测器的I-V测试结果表明暗电流在1e－8～1e－7A之间，α粒子（241Am 5.5MeV）辐照下电流为1e－5～1e－4A．     

Flexible,Durable, and Unconditioned Superoleophobic/Superhydrophilic Surfaces for Controllable Transport and Oil–Water Separation

Superoleophobic/superhydrophilic surfaces have incomparable advantages for oil–water separation and oil droplet manipulation; however, such surfaces are difficult to obtain on the basis of surface tension theory, and existing attempts are either not fully functional or are nondurable. Here, a solution to achieve the combination of superoleophobicity and superhydrophilicity by emphasizing the polar component of surface tension is proposed. The developed surfaces can be flexibly applied to almost any solid substrate and exhibit superoleophobic and instantaneous superhydrophilic property. The surfaces applied to certain substrates can be used for controllable oil transport, oil–water separation, and emulsion demulsification. Furthermore, a novel ferroconcrete‐like structure to substantially increase the durability of the developed surfaces without affecting the superwettability is developed. The coated steel meshes preserve the ability of the material to separate oil–water mixtures even after over 400 m abrasion, which can be a significant step toward its widespread application.     

Organic Ligands Made Porous: Magnetic and Catalytic Properties of Transition Metals Coordinated to the Surfaces of Mesoporous Organosilica

Inorganic solids with porosity on the mesoscale possess a high internal surface area and a well‐accessible pore system. Therefore, it is a relevant task to equip the surfaces of such materials with a maximum density of various organic functional groups. Among these functions it is the capability of coordinating to metal species as a ligand that is of extraordinary importance in many areas, for example, in catalysis. This paper describes how prominent ligands containing donor functions such as carboxylic, thio, chelating, or amine groups can be obtained in the form of nanoporous organosilica materials. The coordination of metal centers such as Co^II, Mn^II, V^IV, or Pt^IV is studied in detail. The magnetic properties of the corresponding materials and some applications in catalysis are reported. A quantitative determination of the surface density of donor atoms by distance measurements using EPR spectroscopy is shown.     

Characterisation of TiN films prepared by electron shower,arc ion-plating and sputtering methods

It has been found that TiN films with high wear resistance and high adhesion can be prepared by electron shower deposition and arc ion plating on glass and austenitic stainless steel (SUS 316) substrates. The high wear resistance is principally explained by the grain size and surface morphology. Fine {100}-faceted crystals (10–150 nm) grew on the surface. The typical morphology of the crystals was triangular pyramidal. The crystallite size was changed by the bias voltage. Faceted crystals produced by arc ion plating were rounded and smoothed by a change in bias, but were unaltered in samples prepared by the electron shower process. The fine faceted surfaces had higher wear resistance than the granularly rounded ones. When TiO₂ was formed at the interface of the glass substrate, the adhesion was lowered. The high-adhesion film prepared by electron shower deposition contained a small amount of TiO₂ at the interface.     

An Anti-Freezing,Ambient-Stable and Highly Stretchable Ionic Skin with Strong Surface Adhesion for Wearable Sensing and Soft Robotics

Natural living systems such as wood frogs develop tissues composed of active hydrogels with cryoprotectants to survive in cold environments. Recently, hydrogels have been intensively studied to develop stretchable electronics for wearables and soft robots. However, regular hydrogels are inevitably frozen at the subzero temperature and easily dehydrated, and have weak surface adhesion. Herein, a novel hydrogel-based ionic skin (iSkin) capable of strain sensing is demonstrated with high toughness, high stretchability, excellent ambient stability, superior anti-freezing capability, and strong surface adhesion. The iSkin consists of a piece of ionically and covalently cross-linked tough hydrogel with a thin bioadhesive layer. With the addition of biocompatible cryoprotectant and electrolyte, the iSkin shows good conductivity in wide ranges of relative humidity (15–90%) and temperature (−95–25 °C). In addition, the iSkin can adhere firmly to diverse material surfaces under different conditions, including cloth fabric, skin, and elastomers, in both dry and wet conditions, at subzero temperature, and/or with dynamic movement. The iSkin is demonstrated for applications including strain sensing on both human body and winter coat, human–machine interaction, motion/deformation sensing on a soft gripper and a soft robot at extremely cold conditions. This work provides a new paradigm for developing high-performance artificial skins for wearable sensing and soft robotics.