Oxygen plasma treatment for reducing hydrophobicity of a sealed polydimethylsiloxane microchannel

Rapid prototyping of polydimethylsiloxane (PDMS) is often used to build microfluidic devices. However, the inherent hydrophobic nature of the material limits the use of PDMS in many applications. While different methods have been developed to transform the hydrophobic PDMS surface to a hydrophilic surface, the actual implementation proved to be time consuming due to differences in equipment and the need for characterization. This paper reports a simple and easy protocol combining a second extended oxygen plasma treatments and proper storage to produce usable hydrophilic PDMS devices. The results show that at a plasma power of 70 W, an extended treatment of over 5 min would allow the PDMS surface to remain hydrophilic for more than 6 h. Storing the treated PDMS devices in de-ionized water would allow them to maintain their hydrophilicity for weeks. Atomic force microscopy analysis shows that a longer oxygen plasma time produces a smoother surface.     

Circadian rhythms in Neurospora crassa on a polydimethylsiloxane microfluidic device for real-time gas perturbations

Racetubes, a conventional system employing hollow glass tubes, are typically used for monitoring circadian rhythms from the model filamentous fungus, Neurospora crassa. However, a major technical limitation in using a conventional system is that racetubes are not amenable for real-time gas perturbations. In this work, we demonstrate a simple microfluidic device combined with real-time gas perturbations for monitoring circadian rhythms in Neurospora crassa using bioluminescence assays. The developed platform is a useful toolbox for investigating molecular responses under various gas conditions for Neurospora and can also be applied to other microorganisms.     

中国经济稳步进入新一轮景气状态

本文讨论了目前中国经济通货紧缩的国内外经济主导力量及其近期显著的演化趋势。在此基础上,我们对中国宏观经济包括经济增长,通货膨胀以及国际收支等变量的近期演变进行了分析,并给出了今明两年的相关预测结果。     

Nano-islands integrated evanescence-based lab-on-a-chip on silica-on-silicon and polydimethylsiloxane hybrid platform for detection of recombinant growth hormone

Integration of nano-materials in optical microfluidic devices facilitates the realization of miniaturized analytical systems with enhanced sensing abilities for biological and chemical substances. In this work, a novel method of integration of gold nano-islands in a silica-on-silicon-polydimethylsiloxane microfluidic device is reported. The device works based on the nano-enhanced evanescence technique achieved by interacting the evanescent tail of propagating wave with the gold nano-islands integrated on the core of the waveguide resulting in the modification of the propagating UV-visible spectrum. The biosensing ability of the device is investigated by finite-difference time-domain simulation with a simplified model of the device. The performance of the proposed device is demonstrated for the detection of recombinant growth hormone based on antibody-antigen interaction.     

Bochner-Riesz空间估计生成的对称复矩阵稳定解

采用Bochner-Riesz矩阵构造对称复矩阵,根据极大熵准则,利用强度离散性微分边界方程不稳定的边界平衡点,动态描述Bochner-Riesz空间中多复变微分方程的线性初值解,用一种鲁棒非平衡的ELM方法,求解一类由Bochner-Riesz空间估计生成的对称复矩阵稳定解,提高系统的稳定性能。     

Low cost fabrication and assembly process for re-usable 3D polydimethylsiloxane (PDMS) microfluidic networks

A method to easily manufacture and assemble a polydimethylsiloxane (PDMS) based microfluidic device is described. The method uses low cost materials and re-usable laser cut polymethyl methacrylate (PMMA) parts. In addition, the thickness of PDMS layers can be controlled and both PDMS layer surfaces are flat, which allows for multi-layer PDMS structures to be assembled. The use of mechanical clamping to seal the structure allows for easy cleaning and re-use of the manufactured part as it can be taken apart at any time. In this way, selected layers can be re-used or replaced. The process described can be easily adopted and utilised without the need for any costly clean room facilities or equipment such as oxygen bonders, making it ideal for laboratories, universities, and classrooms exploring microfluidics applications.     

钢结构防火涂料发展现状研究

简要介绍了钢结构防火涂料的防火原理,分析了当前厚涂型、薄涂型,超薄型及室外钢结构防火涂料的研究和应用,及其在使用过程中存在的主要问题,并提出了具体的改进措施,对我国钢结构防火涂料今后的发展进行了展望并提出建设性的意见.     

纤维素磁性高分子微球的制备方法研究进展

文章从纤维素的应用价值出发,分别介绍了纤维素微球和的纤维素磁性高分子微球的特点及应用范围,详细综述了纤维素及纤维素磁性微球的制备方法。     

对大气污染防治科研工作给予长期稳定支持的思考

目前我国的大气污染形势非常严峻,短期内难以取得明显的治理效果。治理大气污染需要科研工作在基础研究、技术研发等方面提供强有力的支撑。尽管我国对相关的科研工作有多年的长期支持,但未按照长期稳定支持的思路进行设计,导致目前的科研产出成果难以满足治理大气污染的需求。建议借鉴国际经验,突破现有科研支持方式,在大气污染重点方向上建立长期稳定的财政投入机制,加大对重点优秀研发团队持续稳定的支持,建立绩效评估和调整机制,以服务于长期大气污染防治的科技需求。     

时齐马氏链渐进性双曲方程稳定解存在性分析

双曲方程的稳定解分析方法在现代数学应用中具有广泛的意义。采用时齐马氏链进行双曲方程稳定解存在性分析具有模型匹配度高的优点。构建时齐马氏链的双曲波动方程,设计自组织非光滑时滞的双曲系统,结合时齐马氏链渐进性条件下的Lyapunov-Krasovskii泛函算法,对时齐马氏链渐进性条件临界阈值确定,以有效分析双曲方程的稳定解存在性,提高并行算法处理效率,在一阶非光滑时滞系统中得到方向性时齐马氏链函数的分解特征。研究证明,时齐马氏链渐进性条件下,双曲方程存在稳定性解,解向量在有限时间内收敛。     

基于关联度分析的动态稳健高速磨削成屑工艺

传统稳健性高速磨削成屑工艺设计方法仅能对动态特性的个别实例进行分析,缺乏理论的系统性和应用的广泛性。提出一种基于关联度分析的动态稳健高速磨削成屑工艺设计方法,通过一个描述高速磨削成屑产品质量的关联度序列,分析高速磨削成屑工艺响应变量和信号因子间的线性关系,采用灰色关联度评估响应变量与信号因子间的关联程度,基于方差分析表中的百分比对每个因素的重要性进行排序,获取一组确保关联度最大的可控因子水平组合,采用所提方法进行了高速磨削成屑的实例分析,最终得到稳健的高速磨削成屑工艺设计结果。实验结果说明,所提方法能够对高速磨削成屑工艺进行合理的设计,方法的样品废品率和制作效率优于传统方法。     

Researchers Propose AFM-based Virtual Nano-hand for Stable Nanomanipulation

<正>The atomic force microscopy(AFM)is a promising tool for manipulating nano-objects to fabricate nano-structures or nano-devices.However,there are still some challenges facing the development of an AFM-based robotic nanomanipulation system,such as the     

防火涂料在古建筑中的应用研究

我国古建筑是世界上最古老的建筑体系之一,在建造技术和装饰艺术以及布置格局等方面具有悠久的历史传统和辉煌的成就,对我国现代建筑的设计、建造和装饰工艺的发展有着重要而深远的影响。本文分析了我国在古建筑保护上存在的不足之处,然后介绍了防火涂料的类别和阻燃机理,探索了防火涂料在古建筑中的应用。     

浆细胞性乳腺炎研究现状

浆细胞性乳腺炎是乳腺无菌性炎症反应,在中青年女性中发病率较高。近年来,浆细胞性乳腺炎的发病率呈逐年升高的趋势。由于PCM临床症状及实验室检测结果常无明显特异性,因此易被误诊。笔者就PCM的发病原因、病理表现、分型、细菌学表现、影像学表现和治疗的研究进展进行综述,为浆细胞性乳腺炎的临床研究及治疗提供帮助。     

应对外需减弱，保持出口平稳增长——基于SWOT模型的分析

2008年中国外贸增长较为平稳,贸易顺差下降、商品结构优化、多元化战略稳步推进、外商投资规模扩大。但是,由于金融危机将进一步恶化,世界经济发展继续放缓,外贸领域也出现了一些新问题与新情况,如出口增速大幅下降、贸易环境不断恶化等。2009年外部需求将进一步收缩,中国对主要经济体出口将全面放缓,出口企业经营压力继续加大。如何保持出口平稳增长将是我国外贸面临的主要课题。     

Acoustic fabrics enabled by piezoelectric polymer fibersOA

<正>Some 15 years ago,Prof.Yoel Fink at MIT inspired the world by proposing multimaterial fibers that can see,hear,sense and communicate [1] by integrating microelectronic devices into single thermally drawn fiber or fiber assembly.Since then,great progress has been made around the globe [2] to impart these functions into fabrics with such fiber-based devices.