Study on the friction and wear behavior of surface‐modified carbon nanotube filled carbon fabric composites

The functionalization of multi‐walled carbon nanotubes (MWNTs) was achieved by grafting furfuryl amine (FA) onto the surfaces of MWNTs. Furthermore, the functional MWNTs were incorporated into carbon fabric composites and the tribological properties of the resulting composites were investigated systematically on a model ring‐on‐block test rig. Friction and wear tests revealed that the modified MWNTs filled carbon fabric composite has the highest wear resistance under all different sliding conditions. Fourier transform infrared spectroscopy (FTIR), X‐ray photoelectron spectroscopy (XPS), and thermal gravimetric analysis (TGA) revealed that MWNTs were successfully functionalized and the modification led to an improvement in the dispersion of MWNTs, which played an important role on the enhanced tribological properties of carbon fabric composites. It can also be found that the friction and wear behavior of MWNTs filled carbon fabric composites are closely related with the sliding conditions such as sliding speed, load, and lubrication conditions. Copyright © 2010 John Wiley & Sons, Ltd.     

Diffraction grating interferometers for mechanical characterisations of advanced fabric laminates

It is demonstrated that two grating interferometers with high spatial resolutions can successfully be applied for the mechanical characterisation of the advanced fabric composite materials. Based on these two techniques, the mechanical properties of two kinds of fabric laminates are obtained without assumption of uniform strain fields to be used in the characterisation approaches using the local strain sensors. The degree of the yarn crimp effects of the two laminates is compared in terms of the out-of-plane displacement derivatives. Especially, it is shown that the grating shearing interferometer is appropriate for the crimped fabric structure requiring a three-dimensional analysis. The modification from moiré interferometer to grating shearing interferometer is performed by introducing a Michelson interferometer modified for image shearing.     

Implementing minimal clock skew Directed Logic

Although the physics of computing allows the possibility of logic operations with no energy dissipation, over 40 years of work by brilliant scientists in many fields has not achieved it. The solution described here required breaking from the tacit assumptions that logic gates had to be electronic. The system is implemented entirely with passive optical components. Also needed was a logic that could utilize those passive components. Hardy and Shamir showed how to map a Boolean logic problem into a form suitable to be implemented by light flowing through various paths and cascaded as needed. This paper examines a modular approach to implementing their approach (called Directed Logic) in an integrated optical system. We start from unit cells, implementing a dynamic flip-flop principle and combine the cells in a network or “logic fabric.” Contrary to proofs by the founders of this field, speed is limited only by the message bandwidth of the optical signal, and, of course, no energy is dissipated. There are still aspects that need additional work on issues like accuracy using analog components and size relative to electronics. But the basic problem is solved at last and paths toward solving the remaining problems have been identified.     

颗粒材料三维应力路径下的接触组构特性

颗粒材料的宏观应力变形特征与其微观接触力、组构等紧密相关.一般而言,强接触系统属于颗粒内部体系的传力结构,其对应的组构张量是影响宏观应力性质的重要因素.细观数值方法(如离散单元法)能够反映物理试验的基本规律,并且可以方便地提取宏微观数据来研究颗粒体系的应力变形机制.采用离散单元法(discrete element method,DEM)进行一系列等$p$等$b$应力路径下颗粒材料的真三轴试验,在此基础上研究了三维应力路径下颗粒材料的宏微观力学参数的演化过程、三维组构张量与应力张量多重联系以及强接触体系反映的宏观应力特征.研究表明:颗粒体系偏应力峰值状态和临界状态均存在与加载路径无关的宏微观特征;三维应力路径下组构张量与应力张量存在非共轴性,但其联合不变量演化过程表现出加载路径无关的特征;与弱接触系统的组构张量相比,强接触系统的组构张量更能反映宏观应力张量的特征;强弱接触体系的组构张量对颗粒体系宏观响应的贡献不同,其分界点存在一定取值范围,但采用平均接触力较为简单合理.      

燃煤电站布袋除尘器和静电除尘器脱汞性能比较

采用国际上通用的Ontario Hydro方法（OHM）对中国五个燃煤电站布袋除尘器（FF）/静电除尘器（ESP）前、后的烟气进行采样,应用美国EPA标准方法测定了烟气中Hg0、Hg2+和HgP的浓度。应用DMA80测定固体样品（煤、底灰、ESP飞灰）中的汞浓度。由汞平衡得出各个环节中汞所占的份额。由此得到FF和ESP脱除烟气中汞的性能。安装FF的电站1和2的综合脱除效率约为80%和20%,安装ESP的电站3、4和5的综合脱除效率分别为6%、20%和4%左右。这说明FF比ESP有更加优良的脱汞性能,而且FF/ESP脱除烟气中的汞受到很多因素的影响。     

Citronellol-Based Long-Lasting Antibacterial Cotton Fabrics without Bacterial Resistance

Antibacterial cotton helps prevent the growth and spread of harmful microorganisms, reduces the risk of infection, and has a prolonged service life by reducing bacterial degradation. However, most antibacterial agents used are toxic to humans and the environment. Citronellol-poly(N,N-dimethyl ethyl methacrylate) (CD), a highly effective antibacterial polymer, is synthesized from natural herbal essential oils (EOs). CD exhibited efficient, rapid bactericidal activity against Gram-positive, Gram-negative, and drug-resistant bacteria. Citronellol's environmental benignity makes CDs less hemolytic. Notably, negligible drug resistance developed after 15 bacterial subcultures. The CD-treated cotton fabric displayed better antibacterial performance than AAA-grade antibacterial fabric, even after repeated washing. This study extends the practical application of EOs to antibacterial surfaces and fabrics, which is promising for use in personal care products and medical settings.     

布料的太赫兹波透射特性研究

为获得太赫兹波对常见衣物布料的穿透特性,基于布料的物理结构以及太赫兹波传输的影响因素,建立了常见布料的太赫兹波传输模型,计算获得了不同相对湿度条件下典型太赫兹波长对布料的透过率。随后,利用太赫兹时域光谱系统对棉质布料样品进行透射实验测试,获得了布料在0.1~2 THz范围内不同相对湿度条件下的透过率。通过理论计算结果与实验测试结果的对比分析,验证了该传输模型的有效性,获得了太赫兹波对常见棉质布料的穿透特性。此外,在30%相对湿度条件下,实验研究了多层棉质布料的太赫兹透射特性。研究结果表明,在可见光波段"不透明"的衣物布料,利用太赫兹波可实现良好的"透视",但其对布料的穿透特性一定程度上受到环境相对湿度的影响,该研究对于衣物内隐藏危险物品的快速检测具有重要意义。     

聚酯织物表面耐用超疏水涂层的制备及在油水分离中的应用

使用在含有甲基MQ(M:单官能团Si-O单元R₃SiO_1/2, Q:四官能团Si-O单元SiO₂)硅树脂与疏水SiO₂的二甲苯溶液中浸渍的方法,在聚酯织物表面制备了耐用超疏水涂层。经过处理后,微米级聚酯纤维表面被紧密的疏水纳米颗粒包裹,通过这种方法降低了纤维的表面能。聚酯织物展现出良好的超疏水特性,与水滴的静态接触角为156°,滚动角为5°。得到的超疏水聚酯织物在机械磨损、酸碱环境及紫外线照射条件下,表现出了良好的稳定性。此外,用超疏水聚酯织物作为过滤材料得到的油水分离效率达99%以上。该方法为大面积工业制备超疏水织物提供了新的思路。     

光子晶体结构色织物研究进展

针对结构色织物难以产业化的现状,从光学效应和能够产生结构色的周期性结构两个角度系统介绍了结构色织物生色机理。随后,按照结构色织物表面光子晶体结构特征、所用光子晶体基元种类及结构色制备方法,对结构色织物进行了系统分类归纳,并指出了各自的优缺点。此外,现有结构色织物研究均为基于已有纳米粒子尺寸来表征对应结构色颜色,缺乏根据实际颜色需求选取光子晶体尺寸的研究。我们根据现有文献报道的光子晶体基元尺寸与所得结构色织物颜色种类的对应关系,通过计算得到了根据所需织物颜色种类确定光子晶体基元尺寸的公式。最后总结了结构色织物制备存在的问题,并给出了合理建议。     

Combined ultrasonic and gamma-irradiation to prepare TiO2@PET-g-PAAc fabric composite for self-cleaning application

The grafting of polyacrylic acid (PAAc) onto the fabric of Poly(ethyleneterephthalate) (PET) was loaded with TiO₂ by a mixture sonication of TiO₂ dispersed in AAc dissolved in acetone solvent. Ultrasonic irradiation was utilized as a tool for a good dispersion of TiO₂ onto the PET fabric. The grafted PET fabrics with acrylic acid AAc monomer were successfully obtained using gamma-ray induced graft polymerization, the degree of grafting PET-g-PAAc fiber was 105%. The chemical compositions and crystal structure of grafted TiO₂@PET-g-PAAc fabrics were characterized by ATR-FTIR and XRD. It was found that loading of PET fiber with in TiO₂ particles showing the formation of anatase and rutile as performed by XRD. The thermal property of TiO₂@PET-g-PAAc was investigated by differential thermal analysis (DTA). The obtained result indicated the thermal property of the grafted TiO₂@PET-g-PAAc was increased. Image of scanning electron microscope (SEM) indicated the good adherent and good distribution of PAAc and TiO₂ with PET fabric. The self-cleaning property of TiO₂@PET-g-PAAc has been evaluated by using three kinds of dyes as models.