Interactions of 1 μm latex particles with pseudomonas aeruginosa biofilms

Fluorescently labelled latex microbeads were used to study the interaction of particles with Pseudomonas aeruginosa biofilms in a continuous flow annular reactor. Beads were readily distinguished and enumerated in both intact and disaggregated biofilm samples. The fraction of beads that attached to biofilm during a 24 h period ranged from 0.001 to 0.01 and was proportional to biofilm cell carbon and to the standard deviation of biofilm thickness. Microbeads added to biofilm of steady state thickness (30 μm) were observed to be located throughout the entire biofilm depth in 24 h. Many of the microbeads that attached to biofilm shortly after bacterial inoculation (thickness of 2 μm) remained near the substratum as cells grew past and covered them. Microbeads were observed near the biofilm-substratum interface for up to 5 days after bead addition. Beads formed aggregates on biofilms, but not in bulk water. Beads captured by biofilm remained in the reactor system longer than beads that never attached to biofilm.     

碳改性SnSbCu_(0.5)/M-MCMB/C负极材料

对中间相炭微球(MCMB)进行改性,以改性MCMB(M-MCMB)为基体、柠檬酸为碳源,由化学还原法、球磨法及热裂解工艺制得Sn Sb Cu0.5/M-MCMB/C复合材料。用XRD、SEM及恒流充放电等方法研究样品、纯Sn Sb Cu0.5合金和Sn Sb Cu0.5/M-MCMB负极材料。Sn Sb Cu0.5/M-MCMB/C复合材料可缓解纯Sn Sb Cu0.5合金的体积膨胀效应,提高循环稳定性。以100 m A/g在0.01~2.00 V循环,首次放电比容量为648.51 m Ah/g,库仑效率为74.55%,第80次循环的容量保持率为80.26%。     

基于NTC微珠状热敏电阻的稳态测量方法

稳态导热系数测量方法的原理和数学模型简单,但热源均温性要求高和测量时间长限制了稳态导热系数测量方法的实际应用。提出一种测量导热系数的新型微球法稳态热测量方法,建立对应的物理模型和试验方法。通过熔融共混法制备不同质量分数的石墨烯 石蜡复合相变材料,并采用微球法对不同质量分数的石墨烯 石蜡复合相变材料的导热系数进行测量。测量得到样品的导热系数分别为0.278 W/(m·K）(0%)、0.330 W/（m·K）(0.5%)、0.402 W/（m·K）(1%)、0.524 W/（m·K）(2%)、0.604 W/（m·K）(3%)、0.654 W/（m·K）(4%)和0.711 W/（m·K）(5%)。该方法具有微球体积小、热源均匀、测量快、样品制备简单等优点,可应用于实际工程中相变材料和液体的原位导热系数测量。     

由中间相炭微球制备高密度各向同性炭

以中间相炭微球（ＭＣＭＢ）为原料，在常温下压制成型。所用ＭＣＭＢ由不同一次吡啶不溶物含量的煤焦油在不同条件下聚合反通过热过滤及吡啶抽提分离而得。考察了不同原料、成型压力、热处理温度及升温速率对炭制品的密度及收缩率的影响。１０００℃下炭化后炭制品的表观密度最高达１．７５ｇ／ｃｍ＾３。     

基于光谱自编码微球的多样品酶联免疫检测混合筛选

将苯乙烯及其同系物共聚合成具有不同特征光谱的光谱自编码微球,应用于酶联免疫检测(ELISA),AP酶标抗体筛选灵敏度达体积稀释比1∶160000。将20种编码微球与20个样品对映包被后混合,进行多样品ELISA混合筛选,分析阳性信号最强微球的光谱编码,得到了阳性反应样品的编号。成功开发了一种多样品的ELISA混合筛选技术。     

Effect of electrode geometry and charge on the production of polymer microbeads by electrostatics

Experimental parameters which are critical for producing small diameter (i.e. 100-300 μm) polymer microbeads, using electrostatic droplet generation, were investigated with three types of electrodes; a parallel plate, a positively charged needle and a grounded needle with alginate as the polymer. Electrode spacing was a critical factor controlling microbead size, but only for the parallel plate set-up. While the applied potential affected droplet size in all three set-ups, the smallest droplet size was produced with the positively charged needle. In some experiments needle oscillation was observed resulting in even smaller microbeads (i.e. < 100 μm). Calculated microbead diameters agreed well with experimental values.     

中间相炭微球的微晶参数随聚合时间的变化

含有3．7wt％PI的煤焦油在450℃下聚合不同的时间，用XRD测试所得到的中间相炭微球的微晶多数，结果发现中间相发微球的微晶结构与炭微球的收率及其中的杂原子含量有密切的联系。     

炭材料用基体前驱体沥青的改性研究

首次以二乙烯基苯为交联剂,在酸性催化剂的作用下对煤沥青进行了改性研究,同时对改性后的煤沥青进行显微结构和耐热性分析。研究结果表明：改性后的煤沥青不仅出现大量的中间相小球,而且耐热性优良,可作为炭材料优质的基体前驱体。     

Development of Micro-Debond Methods for Thermoplastics Including Applications to Liquid Crystalline Polymers

Micro-bead and related debond techniques were used to study adhesion of liquid crystalline copolyesters (LCPs) and other semi-crystalline thermoplastic polymers to glass fibers. For polymers with poor flow even at high temperatures, symmetric beads on fibers were difficult to prepare so an alternative sample preparation method was developed where glass fibers were inserted into thin sections of molten polymer. Glass fibers of widely-varying diameters were used in order to extend the dynamic range of the debond techniques in terms of debonding area, showing a significant improvement in precision over that demonstrated previously with micro debond techniques. The fibers were freshly prepared in our laboratory and silane coated when necessary, which allowed us to minimize fiber surface heterogeneity effects which are believed to influence strongly debond test results. It was found that chemical bonding of the LCPs was quite favorable as was indicated by fracture surface analysis and by comparison with the shear strength of the neat resins. The apparent poor interphase strength in fiber-reinforced LCP composites is proposed to be due to orientation of the LCP molecules near the fiber interface leading to a cohesively weak layer of LCP near the interface. Reactive silane coupling agents lead to no improvement in interface strength as compared with bare glass because chemical reaction occurs on both surfaces. This results in very strong interfaces leading to polymer cohesive failure near the interface of all thermoplastics studied here     

In situ fabrication of carbon nanotube/mesocarbon microbead composites from coal tar pitch

Carbon nanotube/mesocarbon microbead composites have been synthesized from coal tar pitch with carbon nanotubes. How the carbon nanotubes affect the growth and the structure of mesocarbon microbeads are studied. The result shows that the size of beads decreases when more carbon nanotubes are added, and when the ratio of carbon nanotubes is set at 5%, we get the smallest sample with quite uniform shape. Carbon nanotubes exist both on the surface and inside of the samples and they will inhibit the growth and coalescence of these spheres. The addition of carbon nanotubes decreases the graphitization degree of the samples and makes their microtexture tend to be disordered.