Competing Effects of Radio Frequency Fields on Carbon Nanotube/Resin Systems: Alignment versus Heating

This work shows that radio-frequency (RF) fields can simultaneously align carbon nanotubes (CNTs) dispersed in a resin and induce Joule heating to cure the resin. The timescales of alignment and curing using RF heating are numerically computed and compared at different field strengths in order to determine a temperature where alignment happens before the matrix crosslinks. Composites are experimentally fabricated at the desired target temperature and are optically analyzed and quantified; the CNT network is successfully aligned in the direction of the applied electric field. This methodology can be used to create composites where the local alignment can be varied across the sample. Composites fabricated using RF fields have higher electrical conductivity in the direction of the aligned CNTs than an oven-cured, randomly aligned sample. Also, RF-cured nanocomposites exhibit higher tensile strength and modulus in the direction of alignment compared to an oven-cured sample. Finally, it is further demonstrated how this methodology can be coupled with a direct ink writing additive manufacturing process to induce alignment in any desired direction, even orthogonal to the shear forces in the extrusion direction.     

A comparison of various rheological properties for modelling the kinetics of thermal softening of potato tissue (c.v. Monalisa) by water cooking and pressure steaming

The kinetics which can be used to describe thermal softening of potato tissue by water cooking and pressure steaming were established and the temperature dependence of rheological and textural properties, using six different instrumental objective methods as firmness indicators, was determined within the temperature range of 100–122 °C. In water cooking at 100 °C and in steaming at 100, 112 and 117 °C, the thermal softening was best expressed by one simple pseudo first-order kinetic mechanism, which was considered to be the response to the changes in the pectic material in the cell wall and interlamellar region. Tension energy was the best rheological property for establishing the kinetics of softening of potato by water cooking, whereas maximum shear force was the best method of representing the tissue softening by steaming, using first-order models. Steaming at 122 °C caused overcooking of the tissue, even for short times. At this high temperature, rheological parameters (compression, tension and creep compliance) and textural properties from Texture Profile Analysis (TPA) fitted second-order models. When second-order models were used, the Arrhenius equation was significant for chewiness, indicating that this textural property can be useful for detecting overcooking caused by prolonged pressure steaming in the experimental temperature range.     

刨花板生产中热压工艺理论的研究

介绍了刨花板热压过程中板坯的物理变化和化学变化,分析了热压温度、时间、压力在热压过程中的作用,阐明了热压工艺是刨花板生产中产品质量保证的重要环节。     

How micro-phase separation alters the heating rate effects on globular protein gelation

This study was conducted to determine how the combination of heating rate and pH can be used to alter viscoelastic properties and microstructure of egg white protein and whey protein isolate gels. Protein solutions (1% to 7% w/v protein, pH 3.0 to 8.5) were heated using a range of heating rates (0.2 to 60 °C/min) to achieve a final temperature of 80 °C. The gelation process and viscoelastic properties of formed gels were evaluated using small strain rheology. Single phase or micro-phase separated solution conditions were determined by confocal laser scanning microscopy. In the single phase region, gels prepared by the faster heating rates had the lowest rigidity at 80 °C; however, a common G' was achieved after holding for 4 h at 80 °C . On the other hand, under micro-phase separation conditions, faster heating rates allowed phase separated particles to be frozen in the network prior to precipitation. Thus, gels produced by slower heating rates had lower rigidities than gels produced by faster heating rates. The effect of heating rate appears to depend on if the solution is under single phase or micro-phase separated conditions. PRACTICAL APPLICATION: The effect of heating rate and/or time on protein gel firmness can be explained based on protein charge. When proteins have a high net negative charge and form soluble aggregates, there is no heating rate effect and gels with equal firmness will be formed if given enough time. In contrast, when electrostatic repulsion is low, there is a competition between protein precipitation and gel formation; thus, a faster heating rate produces a firmer gel.     

清洁型油炸设备多烧嘴燃烧加热系统的研制

介绍了一种适合于清洁型油炸设备的多烧嘴燃烧加热系统。该加热系统具有结构紧凑、热强度大、热效率高、安全环保、成本低廉的特点。具有很强的推广应用价值。     

基于静稳极限阻抗圆的新型自适应失磁保护研究

提出了一种基于静稳极限阻抗圆的新型失磁保护判据,新判据能自适应负荷的变化。再综合一些防止非失磁工况影响的闭锁措施,提出了新的自适应失磁保护方案。新保护方案能在各种失磁和非失磁工况下正确、可靠动作。仿真结果证明了新的自适应失磁保护方案的有效性。     

离子筛型锂离子吸附剂的制备

采用高温固相法制备锂离子吸附剂。采用正交实验法对影响吸附率的灼烧时间,温度和水热时间等诸因素进行了讨论,确定了最佳制备条件。实验结果显示:用该吸附剂在室温24℃,液相pH=7.2,锂的初始浓度为6mg/L,对锂的吸附率可达93.2%,吸附量为3.78mg/g。     

对棒多晶硅还原炉高频加热系统研究

介绍了一种新型多晶硅还原炉加热电源的工作原理、系统构成和实验结果。该型加热电源采用相控整流和高频逆变技术。根据多晶硅硅棒在生长过程中的伏安特性,设计了与工频加热电源交互的控制逻辑以及逆变电流控制方法。通过实验验证了硅棒中交变电流的趋肤效应在多晶硅硅棒加热过程中的作用,并对比了工频加热电流与高频加热电流的幅值差异。实验表明,该型多晶硅还原炉高频加热电源在节电率、单炉生产时间和产出硅棒直径上,均比传统的工频加热电源有较大提升。     

厚度横向控制系统在纸机上的应用

<正>牡丹江恒丰纸业抄纸一分厂有一台可以生产多样纸种的纸机,如:卷烟纸、烟用接装纸原纸、圣经纸等。其中,圣经纸是印刷圣经和字典的一种纸页,因此,要求其纸页厚度的均匀、平整。所以,恒丰纸业在2011年3月引进了Honeywell公司的厚度横向控制系统(Calcoil CW),安装在纸机的1#软压光和2#软压光之间。安装使用后,纸页经过厚度横向控制系统,其纸页的均匀性有了明显的改善。     

加热模式对添加葡萄糖氧化酶鲢鱼糜凝胶特性的影响

研究两段法加热模式对添加葡萄糖氧化酶鲢鱼糜凝胶特性的影响。结果表明,在凝胶化阶段,高温短时（40 ℃、1 h）模式下,鱼糜凝胶强度、持水性、白度和不易流动水含量最高,且自由水含量最低,凝胶网络结构最致密;十二烷基硫酸钠-聚丙烯酰胺凝胶电泳（sodium dodecyl sulfate-polyacrylamide gel electrophoresis,SDS-PAGE）图谱显示,在高温短时（40 ℃、1 h）模式下,肌球蛋白重链（myosin heavy china,MHC）条带强度降低,说明此时蛋白降解较多。在熟化阶段时,微波加热鱼糜凝胶的凝胶强度、持水性和白度最高,三氯乙酸-溶解肽含量、自由水含量和孔隙当量直径最小,形成了有序致密的三维网络结构;SDS-PAGE图谱显示,相比水浴加热,微波加热下MHC条带强度更高,说明微波加热促进了二硫键的形成。因此,适宜的加热模式能改善鱼糜凝胶的品质。