石墨烯的制备与应用

简要回顾了石墨烯的历史及性质,着重介绍了石墨烯的制备和表征方法,概述了石墨烯在锂电池、计算机芯片及减少纳米元件的噪声等领域的应用,并展望了其未来发展前景。     

Economic evaluation of alternative wastewater treatment plant options for pulp and paper industry

Excessive water consumption in pulp and paper industry results in high amount of wastewater. Pollutant characteristics of the wastewater vary depending on the processes used in production and the quality of paper produced. However, in general, high organic material and suspended solid contents are considered as major pollutants of pulp and paper industry effluents. The major pollutant characteristics of pulp and paper industry effluents in Turkey were surveyed and means of major pollutant concentrations, which were grouped in three different pollution grades (low, moderate and high strength effluents), and flow rates within 3000 to 10,000 m³/day range with 1000 m³/day steps were used as design parameters. Ninety-six treatment plants were designed using twelve flow schemes which were combinations of physical treatment, chemical treatment, aerobic and anaerobic biological processes. Detailed comparative cost analysis which includes investment, operation, maintenance and rehabilitation costs was prepared to determine optimum treatment processes for each pollution grade. The most economic and technically optimal treatment processes were found as extended aeration activated sludge process for low strength effluents, extended aeration activated sludge process or UASB followed by an aeration basin for medium strength effluents, and UASB followed by an aeration basin or UASB followed by the conventional activated sludge process for high strength effluents.     

Foldable Printed Circuit Boards on Paper Substrates

This paper describes several low‐cost methods for fabricating flexible electronic circuits on paper. The circuits comprise i) metallic wires (e.g., tin or zinc) that are deposited on the substrate by evaporation, sputtering, or airbrushing, and ii) discrete surface‐mountable electronic components that are fastened with conductive adhesive directly to the wires. These electronic circuits—like conventional printed circuit boards—can be produced with electronic components that connect on both sides of the substrate. Unlike printed circuit boards made from fiberglass, ceramics, or polyimides, however, paper can be folded and creased (repeatedly), shaped to form three‐dimensional structures, trimmed using scissors, used to wick fluids (e.g., for microfluidic applications) and disposed of by incineration. Paper‐based electronic circuits are thin and lightweight; they should be useful for applications in consumer electronics and packaging, for disposable systems for uses in the military and homeland security, for applications in medical sensing or low‐cost portable diagnostics, for paper‐based microelectromechanical systems, and for applications involving textiles.     

基于ASP与SQL Server 2000的在线考试系统的设计与实现

为了完成一次高质量的在线考试,该系统采用B/S模式,以ASP为网页架构支持,与SQL Server 2000数据库连接,实现对试题数据库的添加、查询和修改等操作。系统在网页上成功地组建了一份高质量的试卷,并对考试过程中可能出现的问题做了深入的分析,完成了一次完整的考试过程。另外,还把自动组卷和在线考试两个子系统新颖地组合起来,实现教师和学生两个入口在一个系统简单登陆和操作。     

Membrane evaluation for the treatment of acidic clear filtrate

The total effluent load of a paper mill can be significantly decreased by recycling of purified clear filtrate (CF) back to paper-making process. The CF treated with membranes can be reused, for instance, as wire section shower water and in the dilution of chemicals. The main requirements for a membrane in CF treatment are high filtration capacity, high retention of turbidity and low fouling tendency. Previous studies have shown that the regenerated cellulose (RC) ultrafiltration (UF) membrane C30F (current trade name UC030T) is especially suitable for the treatment of paper mill process waters. Every paper-making process is, however, different. Thus, filtration experiments are required in order to find the most optimal membrane for the treatment of a certain process water. In this study the best membrane for the treatment of acidic clear filtrate (ACF) was searched. The performance of the C30F membrane was compared with five UF and three microfiltration (MF) membranes. The results revealed that in addition to the C30F membrane, also some other membranes produced high filtration capacity with ACF (approximately 200 L/(m²h bar)). All the tested membranes also retained over 90% of turbidity. The extremely hydrophilic C30F membrane had, however, lower fouling tendency compared to the other tested membranes. Therefore, it was concluded that the C30F membranes were the best possible membrane for the ACF treatment.     

Self‐Assembled Graphene–Enzyme Hierarchical Nanostructures for Electrochemical Biosensing

The self‐assembly of sodium dodecyl benzene sulphonate (SDBS) functionalized graphene sheets (GSs) and horseradish peroxidase (HRP) by electrostatic attraction into novel hierarchical nanostructures in aqueous solution is reported. Data from scanning electron microscopy, high‐resolution transmission electron microscopy, and X‐ray diffraction demonstrate that the HRP–GSs bionanocomposites feature ordered hierarchical nanostructures with well‐dispersed HRP intercalated between the GSs. UV‐vis and infrared spectra indicate the native structure of HRP is maintained after the assembly, implying good biocompatibility of SDBS‐functionalized GSs. Furthermore, the HRP–GSs composites are utilized for the fabrication of enzyme electrodes (HRP–GSs electrodes). Electrochemical measurements reveal that the resulting HRP–GSs electrodes display high electrocatalytic activity to H₂O₂ with high sensitivity, wide linear range, low detection limit, and fast amperometric response. These desirable electrochemical performances are attributed to excellent biocompatibility and superb electron transport efficiency of GSs as well as high HRP loading and synergistic catalytic effect of the HRP–GSs bionanocomposites toward H₂O₂. As graphene can be readily non‐covalently functionalized by “designer” aromatic molecules with different electrostatic properties, the proposed self‐assembly strategy affords a facile and effective platform for the assembly of various biomolecules into hierarchically ordered bionanocomposites in biosensing and biocatalytic applications.     

纸厂回收淀粉用于纸张施胶剂的制备与应用

以纸厂回收并经过处理的废淀粉作为聚合物的主链,通过接枝苯乙烯(St)、丙烯酸丁酯(BA)及甲基丙烯酸甲酯(MMA)等单体,合成出一种稳定的苯丙乳液施胶剂。结果表明:当w(引发剂)=2.5%~4%、反应温度为70~80℃和m(总单体)∶m(废淀粉)=1∶1.5时,废淀粉接枝共聚物乳液施胶剂的综合性能最好;该施胶剂能有效提高原纸张的各项性能,在同等条件下其性能略低于市售施胶剂;废淀粉回收价格较低,将其用于纸张施胶剂的制备,可达到降低污染、节约成本等目的。     

透明纳米纤维纸的性能与制备方法

透明纳米纤维纸采用与传统纸张相同的化学组成和相似的制备过程。纤维素作为这种纸的主要成分,当纤维素的尺寸减小到15 nm时,纳米纤维纸便显示出了优良的特性,如透明度好,高模量(13 GPa),高强度(223 MPa),还有极低的热膨胀系数(8.5×10-6 K-1)。文章综述了透明纳米纤维纸的性能与制备方法。     

纳米尺寸壳核型苯丙乳液的合成及应用

以苯乙烯(ST)为硬单体,丙烯酸丁酯(BA)为软单体,N-羟甲基丙酰胺(NMA)为交联剂,选用十二烷基硫酸钠(SDS)和辛基酚聚氧乙烯醚(OP-10)复合体系为乳化剂,过硫酸铵(APS)为引发剂,采用半连续乳液聚合法合成了苯丙乳液。通过对浸渍后汽车工业滤纸的性能检测,确定了最佳反应条件。最佳反应条件为:m(丙烯酸丁酯)/m(苯乙烯)=0.49,乳化剂3.5 g,引发剂2.394 g,N-羟甲基丙烯酰胺20.14 g,反应温度88~90℃。所得乳液胶粒呈球形,粒径分布范围小,粒径约为50 nm。浸渍后滤纸的性能指标为耐破度大于350 kPa,耐水性大于300 min,透气度大于510 L.m-2.s-1,挺度大于4.03 mN.m。     

纤维水镁石在造纸中的应用研究

天然纤维水镁石呈纤维集束状,经剥离处理后,集束打开分散成许多细小单束纤维,可与植物纤维复合造纸替代部分植物纤维,降低生产成本。通过实验,在保证纸张质量的情况下,纤维水镁石的添加量可达30％。