碳纤维增强热塑性树脂基复合材料的研究现状

综述了国内碳纤维增强聚酰胺（PA6）、聚醚砜（PES）、聚碳酸酯（PC）、聚苯硫醚（PPS）、聚醚砜酮（PPESK）,聚醚醚酮（PEEK）、热塑性聚酰亚胺（PI）等热塑性树脂基复合材料研究现状,对比了热固性树脂基复合材料与热塑性树脂基复合材料性能及成型工艺方面的差异,并对碳纤维增强热塑性树脂基复合材料的成型方法,碳纤维...     

苯乙炔苯酐型热固性聚酰亚胺的合成与表征

热固性聚酰亚胺是一类先进复合材料基体树脂,相对于热塑性聚酰亚胺具有更高的耐温等级和更好的加工性能,因而作为树脂基复合材料和黏结剂在航空航天等领域应用更为成功。4-苯乙炔苯酐及其衍生物兼具有聚酰亚胺所必需的黏结性、耐热性和机械强度,其利用价值极高,是航空航天用复合材料母体树脂的原料。     

长纤维和连续纤维增强热塑性塑料

近年来,人们成功地研制出复合材料用的高性能热塑性塑料基体,如:聚亚苯基硫醚(PPS)、聚醚醚酮(PEEK)、聚砜(PS)、聚醚砜(PES)和线型芳香族聚酰亚胺(LARC-TPI)等。用这些高性能的热塑性树脂制成的复合材料,其性能超过热固性复合材料的性能,增加了复合材料的韧性、抗冲性、可修复性、抗湿性能和再成型能力等,使热塑性复合材料的应用更加广泛。本文主要介绍新型长纤维和连续纤维增强热塑性塑料。     

面向空天动力用聚酰亚胺树脂基复合材料介尺度结构与调控

基于面向空天动力用聚酰亚胺树脂基复合材料的背景,分析了复合材料面临的介尺度结构设计与调控的关键科学问题及研究思路。综述了国内外热塑性聚酰亚胺构-效设计、复合材料微/纳复合界面强化以及健康结构动态监测的基础研究,并提出了未来的发展趋势。     

高性能聚酰亚胺复合材料的研究进展

综述了国内外高性能聚酰亚胺复合材料的研究进展,主要包括以双马来酰亚胺树脂、反应型聚酰亚胺（PMR型聚酰亚胺）树脂及乙炔基封端聚酰亚胺树脂作为基体材料的复合材料,也包括以聚酰亚胺纤维作为增强体的复合材料,针对结构与性能的关系以及材料的性能优化进行了介绍,并对聚酰亚胺复合材料的发展方向进行了展望。     

复合材料用高性能纤维及热塑性树脂发展现状

介绍了芳纶、碳纤维和超高相对分子质量聚乙烯等3种纤维的基本性能、国内外生产及应用情况,还介绍了聚酰胺、聚醚醚酮、聚苯硫醚及聚酰亚胺等4种热塑性树脂的性能及在研发和生产方面与国外的差距,由此提出了加强研究机构与企业充分合作、国产材料应用及原材料质量控制的建议,并对今后热塑性复合材料的发展进行了展望。     

树脂基泡沫复合材料研制成功

以不饱和聚酯树脂、环氧树脂、聚酰亚胺树脂以及各种高性能热塑性树脂为基体,以空芯玻璃微珠,陶瓷微珠、塑料微珠等为填充料,以特定的成型工艺所制得的泡沫复合材料在航空航天部637所研制成功。 这种泡沫复合材料的密度是由加入到树脂基体     

树脂基复合材料在汽车上的应用分析

轻量化、绿色环保和舒适安全性将成为我国汽车用材料未来发展方向,树脂基复合材料将是实现汽车轻量化、塑料化的材料之一.介绍了玻璃纤维毡增强热塑性复合材料(GMT)、长纤维增强热塑性复合材料(LET)、天然纤维增强热塑性复合材料(NMT)和碳纤维增强复合材料(CFRP)等的特点和应用实例分析.树脂基复合材料的应用是汽车轻量化设计和选材的发展趋势.     

耐磨自润滑热塑性聚酰亚胺复合材料研究

采用双螺杆共混挤出的方法,在热塑性聚酰亚胺中加入有机或无机填料进行改性研究,通过加入(1)PTFE、石墨、二硫化钼等填料;(2)碳纤维、玻璃纤维、金属晶须等填料;(3)其他高分子树脂,制备具有耐磨、自润滑特性的高性能聚酰亚胺复合材料。并对不同配方体系进行熔指、拉伸及弯曲性能、缺口冲击强度等表征,以获得综合性能优越、成本低廉、工艺性能优秀的耐磨自润滑热塑性聚酰亚胺复合材料。     

高性能热塑性树脂基复合材料的研究进展

近些年来,纤维增强热塑性树脂基复合材料已逐步发展成为复合材料中一个高性能、低成本的新型材料家族。本文主要介绍了各种高性能工程塑料和增强纤维的发展,连续纤维增强热塑性树脂的浸渍工艺及成型工艺,最后还介绍了热塑性纤维复合材料的发展趋势。     

Design and optimization of the gel solar pond

The gel pond concept is a unique modification of the conventional salt gradient solar pond. It replaces the salinity gradient zone by a transparent polymer gel and thereby eliminates all problems of instability associated with the former. A framework for the preliminary design of a gel pond to serve different purposes has been presented here. Heat extraction at constant pond storage zone temperatures of 40°–80°C at storage zone depths of 2–5 m has been considered and optimum pond dimensions have been predicted depending upon maximum and minimum heat load constraints. The computer simulations are carried out with the meteorological conditions for Albuquerque, New Mexico. For example, the simulations show that the gel pond can provide an average heat load of 107 W/m², a typical domestic water heating requirement, at a constant pond temperature of 40°C with a storage zone depth of 4.0 m and gel thickness of 0.6 m. For the case of power generation, the pond can provide a minimum of 32 W/m² at a constant pond temperature of 80°C with a storage zone depth of 4 m and gel thickness of 0.6 m. These factors combined with the easy operation and maintenance of the gel pond seem to make it a better alternative compared with the conventional salt gradient pond.     

Energy–exergy–ANN analyses of solar-assisted fluidized bed dryer

In this study, a temperature-controlled solar air collector was designed and tested for drying. Solar drying systems have two disadvantages. First one is the lack of ability to store energy and the second one is the lack of temperature control. This study presents the experimental analysis of an air collector that is able to keep the drying air temperature at 40°C even in cases where the level of solar radiation received by the collectors changes. Most of the tests were performed at a solar radiation level ranging from 500 to 900?W/m² and at an air flow of 3 to 5?m/s. The system tested for drying three different crops separately performed 21?h of a total of 27-h drying period at or above the temperature set of 40°C. The thermodynamic analysis of the relationship between solar radiation, air temperature, flow, and the produced energy was performed. The relationship between productivity, energy produced, and set temperature was analyzed using distribution charts. Moreover, an artificial neural network model was used to estimate outlet air temperature from the solar collectors based on air flow, solar radiation, and outside air temperature.     

Mass flow rate prediction of a thermosiphon solar air-heater

A flat-plate solar air-heater was analyzed and tested. A model was proposed to predict air mass-flow rate at any operating condition. The model showed good agreement with experimental data.     

Integrated performance of stepped and single basin solar stills with mini solar pond

An attempt is made to enhance the productivity of the solar stills by connecting a mini solar pond, stepped solar still and a single basin solar still in series. Experiment is also carried out by replacing the single basin solar still into a wick type solar still. For further augmentation of the yield, baffle plate, pebble, fins, wicks and sponges are added. Day and night productivity of the solar stills for these modifications is studied. Daily efficiency and percentage increase in productivity for these modifications are also studied. Industrial effluent water is used as feed. Theoretical analysis gives very good agreement with experimental results.     

太阳能海水淡化新技术综述

依据太阳能的光效应和热效应对传统的海水淡化进行分类,列举了太阳能与传统蒸馏法与渗析法的结合形式,指出了传统蒸馏法效率不高的原因,重点介绍利用冷凝潜热和提升换热效率的新型高效海水淡化技术以及反渗透的能量回收装置,认为将太阳能与传统海水淡化技术有机结合起来前景广阔,并简述了太阳能收集器的研究现状及先进技术,为太阳能海水淡化技术的进一步研究和发展提供了参考与依据.     

TECHNICO-ECONOMICAL FEASIBILITY OF SOLAR-ASSISTED VIRGINIA TOBACCO CURING

The technical and economical feasibility of using solar energy for curing Virginia tobacco in the bulk barn is investigated. The results illustrate that the energy saving obtained by each type of the system studied is limited because of the nature of the tobacco curing energy requirement. From the technical point of view, the system using water as a heat transfer fluid with an evacuated solar collector shows the best performance. To be economically competitive, the systems need to be multi-purpose: for example, they can be used for space and water heating or for drying other crops during the off-season for tobacco.     

太阳能海水淡化与空调装置控制系统研究

阐述了太阳能海水淡化与组合式空调系统的原理,该系统具有高效的海水淡化功能和空调除湿能力.比较了多个现有的控制器,对该装置的控制系统做出了初步设计并进行了实验验证.最终的实验结果证实该控制器完全可行.     

DRYING OF MEDICINAL PLANTS WITH SOLAR ENERGY UTILISATION

ABSTRACT

In the paper, a potential of solar energy for drying of medicinal plants in Polish conditions is estimated and development of solar drying technologies is presented. The results of economic assessment of flat-plate solar collectors applied for drying of medicinal plants on a farm are promising. In some specific conditions, e.g. drying of wild grown medicinal plants in remote areas, even application of photovoltaic modules for driving of a fan of a solar dryer is a profitable option and enables easy control of the drying air temperature.     

Synthesis and photovoltaic properties of donor–acceptor polymers incorporating a structurally-novel pyrrole-based imide-functionalized electron acceptor moiety

A structurally-novel pyrrole-based imide-functionalized electron accepting monomer unit, 4,6-dibromo-2,5-dioctylpyrrolo[3,4-c]pyrrole-1,3(2H,5H)-dione (DPPD), was prepared. The new DPPD unit was copolymerized with pyrrole-based electron rich monomers, such as thiophene-(N-alkyl)pyrrole-thiophene (TPT) and fused thiophene-(N-alkyl)pyrrole-thiophene (DTP) derivatives, to afford two new polymers, namely P(TPT-DPPD) and P(DTP-DPPD), respectively. The two polymers showed a strong absorption band at 300–600 nm and 300–650 nm, respectively, and their calculated optical band gaps were 2.09 eV and 1.89 eV, respectively. The electrochemical analysis reveals that the highest occupied molecular orbital (HOMO) energy levels of P(TPT-DPPD) and P(DTP-DPPD) were positioned at −5.55 eV and −5.24 eV, respectively, whereas their lowest unoccupied molecular orbital (LUMO) energy levels were positioned at −3.46 eV and −3.35 eV, respectively. The preliminary photovoltaic properties of the polymers, P(TPT-DPPD) and P(DTP-DPPD), were examined by fabricating polymer solar cells (PSCs) with each polymer as an electron donor and PC₇₁BM as an electron acceptor. The PSCs fabricated with the configuration of ITO/PEDOT:PSS/P(TPT-DPPD) or P(DTP-DPPD):PC₇₁BM/LiF/Al showed maximum power conversion efficiency (PCE) of 0.73% and 1.64%, respectively.     

DESIGN AND CONTINUOUS OPERATION OF A SOLAR CONVECTION DRIER WITH AN AUXILIARY HEATING SYSTEM

A solar drier of the through-draft type (4 trays at 0.5 m² surface area) with natural air convection and an auxiliary gas heating system was constructed. General relationships between the climatic conditions of the ambient air, product load and drying characteristics were established. Test runs with the drier as continuous equipment were carried out over a period of 24 h, using carrot dice as experimental material. Air flow rates through the dryer between 100 and 140 kg/h and overall drying rates between 1.5 and 2 kg/h were reached. The overall energy efficiency coefficient for the hybrid heating system amounted to 27 % as compared to 31 to 37 % for the solar energy heating alone and to 22 to 27 % for gas heating energy alone. A combination of continuous drying in the first stage with subsequent batch-wise finish drying in the same or a supplementary drier seems to be advantageous.