多壁碳纳米管对正十八烷相变性能的影响

采用几种不同类型的多壁碳纳米管与正十八烷混合,从官能团种类、多壁碳纳米管的直径和长度及含量等多方面来考察多壁碳纳米管对正十八烷相变性能的影响.实验中将高导热系数的多壁碳纳米管添加入正十八烷中后,混合物的相变温度变化不大,而热焓效率明显降低,且多壁碳纳米管含量越高,热焓效率降低幅度越大.当多壁碳纳米管的含量相同时,含有官能团化多壁碳纳米管的正十八烷的热焓效率低于常规多壁碳纳米管体系.并且混合物的热焓效率随多壁碳纳米管直径的降低迅速下降,而多壁碳纳米管的长度对热焓效率影响不大.结果表明,多壁碳纳米管表面对于正十八烷的吸附是造成热焓效率下降的主要原因.     

多壁碳纳米管对单质硫正极材料电化学性能的改性

为增强单质硫电极的导电性能和抑制活性硫在电解液中的溶解,选用高比表面积、强吸附能力的多壁碳纳米管作为非活性添加剂,通过密封分段加热的方式与单质硫形成复合材料。X射线衍射(XRD)、扫描电子显微镜(SEM)和比表面积(BET)测试均表明单质硫均匀分散到碳纳米管基体中。电化学测试显示添加碳纳米管的硫电极首次放电比容量高达1 487.0mAh.g-1,硫的利用率达到了88.9%,循环50次后比容量还保持在913.7mAh.g-1,较之普通硫电极其电化学性能得到显著改善。     

聚氨酯/多壁碳纳米管抗静电涂料的制备与性能研究

为研究采用多壁碳纳米管在聚氨酯清漆中的抗静电效果,制备了一系列抗静电涂料,结果表明聚氨酯/多壁碳纳米管涂料可以满足抗静电需要(即表面电阻率在105～109Ω范围).碳纳米管含量与电性能曲线为典型渗流曲线,其渗流阈值为2wt％.在较低的添加量(2wt％)时,碳纳米管表电性能优于炭黑,当添加量较高(5wt％)时,其电性能反而比炭黑差,采用适当的酸处理的方法可以进一步提高聚氨酯/多壁碳纳米管的导电性能.     

原位复合聚芳硫醚砜/多壁碳纳米管复合材料的制备及性能初探

采用原位复合法制备了聚芳硫醚砜/多壁碳纳米管(MWCNTs)复合材料,先将酸化前后的多壁碳纳米管与聚芳硫醚砜各自进行原位复合,发现未酸化处理的碳纳米管在聚芳硫醚砜基体中的相容性很差,在基体内部不能有效地分散;此外,还发现随着碳纳米管添加量的增加,其体积电阻率由1013.9Ω.m降到104.3Ω.m,同时其热稳定性也随之逐渐升高。     

多壁碳纳米管的分散性研究

以多壁碳纳米管为原料,添加十二烷基苯磺酸钠进行表面活化,并溶于乙醇中,用超声震荡法分散多壁碳纳米管,采用扫描电镜（SEM）对其进行粒子表征。结果表明,运用超声振荡法分散的多壁碳纳米管分散情况良好,碳纳米管直径在30--50nm之间,能够达到较好的分散效果。     

多壁碳纳米管增强铝基复合材料的高温力学性能EI北大核心CSCD

采用搅拌摩擦加工技术制备不同含量多壁碳纳米管增强铝基复合材料,并对复合材料高温力学性能进行研究。结果表明:多壁碳纳米管的添加使得铝基体材料微观组织更加细小,并形成了少量纳米晶;铝基体中有较高密度位错,并在局部呈位错缠结状分布。与未添加多壁碳纳米管的铝基体相比,复合材料的高温拉伸强度明显增强,且随着碳纳米管含量的增加,复合材料强度逐渐提高,而高温塑性不断降低,350℃时,6.6%(体积分数)MWCNTs/Al复合材料的抗拉强度达到78MPa,为未添加多壁碳纳米管铝基材强度的3.9倍;断口分析表明,随着测试温度的提高,韧窝逐渐变小,呈脆性断裂特征。     

多壁碳纳米管的超声处理对PtRu／MWCNTs电催化性能的影响

多壁碳纳米管的表面官能团化对其在催化领域的应用有重要意义.在硫酸和硝酸混合液中超声处理多擘碳纳米管,在使其纯化的同时,纳米管的长度变短,端口被打开,并在碳纳米管表面和端口处修饰上大量的含氧官能团,有利于催化剂活性组分在碳纳米管表面均匀沉积.利用透射电镜.红外光谱和拉曼光谱表征了碳纳米管及其催化剂的表观织构.通过交流阻抗谱对催化剂进行电化学性能测试,并发现经过超声处理的碳纳米管负载的PtRu双金属催化剂对甲醇有较好的电催化活性.     

多壁碳纳米管复合材料在8 mm 波段的吸波性能

将相同厚度不同碳纳米管含量, 以及不同厚度相同碳纳米管含量的多壁碳纳米管加入玻璃纤维增强复合材料中, 并研究了其在26. 5～40. 0 GHz 频段的吸波性能。结果发现, 多壁碳纳米管具有吸波性能, 而且吸波性能随着多壁碳纳米管含量的增加而提高。多壁碳纳米管/ 玻璃纤维/ 环氧树脂复合材料层板在26. 5～40. 0 GHz频段表现出较好的吸收效果, 其吸波性在于碳纳米管本身具有吸波性能, 此外还与吸波材料的谐振吸波原理有关。通过对该复合材料的电磁参数的测定并计算, 证明实验结果与吸波原理相符合。      

功能化多壁碳纳米管的抗菌行为研究

分别以十二烷基苯磺酸钠、十八烷基三甲基溴化铵及两者的复配体系为分散剂对多壁碳纳米管进行非共价功能化处理,并考察了它们对多壁碳纳米管的分散能力。TG、FT-IR、UV-Vis吸收光谱和TEM分析结果表明,表面活性剂分子已成功吸附在多壁碳纳米管表面且复配体系对多壁碳纳米管的分散能力高于单一表面活性剂。另外,以金黄色葡萄球菌为实验菌种,通过考察功能化多壁碳纳米管悬浮液处理该菌2h后的光密度生长曲线和平板计数结果可知,复配体系功能化的多壁碳纳米管具有良好的抗菌活性。     

多壁碳纳米管的表面乙烯基功能化

本文采用浓硫酸/浓硝酸(3:1,v/v)组成的混酸体系在140℃时对多壁碳纳米管进行了氧化处理,并通过氧化后在多壁碳纳米管表面生成的羟基官能团与丙烯酰氯进行反应,制备了表面乙烯基功能化的多壁碳纳米管.强酸氧化后多壁碳纳米管的表面形貌通过透射电子显微镜进行了观察,结果表明氧化时间为60分钟时所得多壁碳纳米管的长度比较均匀,长径比较大,具有明显的两端开口结构.氧化后多壁碳纳米管表面的官能团通过核磁共振波谱仪进行了表征,结果表明混酸氧化处理60分钟后的多壁碳纳米管的管壁和管端生成了羟基等官能团.氧化后的多壁碳纳米管与丙烯酰氯充分反应后的产物的核磁共振氢谱图表明,反应产物为乙烯基功能化的多壁碳纳米管.     

三维碳/碳复合材料板件拉伸强度预报

针对三维碳/碳复合材料板件开孔敏感性问题进行了试验与有限元分析。建立了三维碳/碳复合材料代表体积单元(RVE)和完好板件、开孔板件的有限元模型,给出了宏观应力到细观应力的转换方法,并基于此方法,实现了完好板件、开孔板件拉伸破坏过程的数值模拟。进行了三维碳/碳复合材料完好板件和开孔板件的单向拉伸试验,模拟计算结果与试验结果吻合良好。分析了不同宽径比(WTDR)对开孔板件拉伸强度的影响,其中当宽径比达到6时,开孔板拉伸极限强度相比完好板下降11.5%,可以认为如果宽径比不低于6,开孔对板件拉伸极限强度影响较小。该结论可以为碳/碳复合材料开孔板件设计提供指导。     

Investigations on the corrosion of flash chamber floor plates in a multistage flash desalination plant

This article presents the results of an investigation on the corrosion of flash chamber floor plates in a multistage flash (MSF) desalination plant. In an MSF plant, desalinated water is produced by flashing deaerated seawater in successive flash chambers under reduced pressure. The flash chamber floor plates were made of carbon steel with AISI type 317L stainless steel (UNS S31703) internal cladding. The thickness of the carbon steel and cladding was 8.5 and 3 mm, respectively. Approximately four years after the plant was commissioned, indications of corrosion processes, in the form of numerous red-colored spots, were noticed on the floor plates. The cause of corrosion was determined by examining the operating history, conducting an on-site visual examination coupled with an in situ material analysis of the floor plates (through the use of a portable alloy analyzer), and analyzing the corrosion products with energy-dispersive X-ray analysis. The corrosion was attributed to frequent shutdowns and fairly long periods of stagnant high-chloride water on the floor plates during shutdown. Recommendations are given to prevent/minimize such failures.     

Prediction of debonding strength of tensile steel/CFRP joints using fracture mechanics and stress based criteria

In this paper, the debonding strength of axially loaded double shear lap specimens between steel plates and carbon fibre reinforced plastic plates is investigated from the analytical, numerical and experimental point of view. Two steel plates were joined together by two carbon fibre reinforced plastic (CFRP) plates and epoxy adhesive in order to realize double shear lap specimens of different length. Failure of the steel-adhesive interface was identified as the dominant failure mode and fracture mechanics and stress based approach are presented in order to estimate the relevant failure load. A good agreement between the analytical-numerical results and experimental data is achieved.     

CFRP板加固含裂纹受拉钢板的疲劳性能研究

根据线弹性断裂力学理论,采用“三维块体-弹簧-板”有限元模型对裂纹尖端的应力强度因子幅值进行计算,并基于Paris-Erdogan裂纹扩展模型,提出了CFRP板加固含裂纹受拉钢板的疲劳寿命预测方法。然后对4个CFRP板加固含初始疲劳裂纹钢板的受拉疲劳性能进行了试验研究,考察了碳纤维板加固量、单面和双面加固方式对疲劳性能的影响。试验结果表明,CFRP板加固钢板的疲劳寿命比未加固钢板显著提高,疲劳裂纹扩展的试验结果与预测结果符合较好。     

炭纤维增强聚合物复合材料骨折内固定板的研究进展

综述了用于骨折内固定板的炭纤维增强聚合物复合材料（包括可吸收和不可吸收的基体）的最新研究进展,重点介绍了炭纤维增强聚合物复合材料的力学性能和生物相容性,另外,还介绍了炭纤维的生物相容性和可吸收性。     

Vibration analysis of laminated composite plates: TV-holography and finite element method

An experimental and numerical investigation into the structural behaviour of symmetrically laminated carbon fibre-epoxy composite rectangular plates subjected to vibration. The laminated composite plates are composed on layers of Grafil XAS carbon fibres preimpregnated in 914C Fibredux epoxy resin and each plate was vibrated by a piezoelectric transducer (PZT) attached onto its surface. The specimens tested were of two different length to width ratios and of symmetric stacking sequence. In this study the short edges of the plate were of various combinations of clamp and free support conditions, and the long edges of the plate were of various combinations of free and simple support conditions. Experimental and finite element studies were carried out in parallel. The experimental vibrational response of the test plates were obtained using a TV-holography technique. The comparison between experimental results and finite element results are reasonably good in all the cases studied.     

循环加载条件下复合材料层板的剩余刚度试验研究

对玻璃纤维／环氧和碳纤维／环氧复合材料层板进行了循环拉伸加载试验，研究了纤维铺设角度对复合材料层板力学性能的影响。通过对多种复合材料层板循环拉伸加载，观察复合材料的剩余刚度变化的一般规律，为复合材料的优化设计提供必要的理论依据。     

Finite element analysis using interfragmentary strain theory for the fracture healing process to which composite bone plates are applied

The present paper deals with finite element analyses to estimate the healing efficiency of fractured long bones to which various composite bone plates are applied. To estimate the callus modulus according to the healing period, interfragmentary strain theory was used, and the iterative process for updating the newly determined callus properties in every finite element was implemented by a user-defined sub-routine constructed by the Python code. The results of analysis revealed that a composite bone plate made of a plain weave carbon/epoxy composite whose Young’s modulus was in the range of 30–70 GPa produced a positive effect on the healing efficiency relieving stress-shielding effect. This result can be used in the detailed design of high-performing composite bone plates to determine more effective shapes and stacking sequences for better healing efficiency.     

缠绕成型混杂纤维复合材料静态拉伸性能研究

研究了T700碳纤维/玻璃纤维、T700碳纤维/玄武岩纤维不同纤维配比混杂材料的层合板拉伸性能。结果表明,混杂纤维层合板的拉伸性能随着碳纤维含量提高而提高;高断裂位移的纤维可以提高混杂纤维复合材料的断裂伸长率。复合材料模量混杂公式得到的理论值与实际测量值比较接近;加入玻璃纤维或玄武岩纤维可以提高复合材料的韧性,同时节省成本。     

铝合金裂纹板的阳极化处理与复合材料补片胶接修理效果

采用磷酸阳极化方法对胶接修理铝合金裂纹板的粘接表面进行了处理,并用单向碳纤维/环氧复合材料补片对铝合金进行了修补.测试了阳极化铝合金的粘接性能、修补结构的静态力学性能和疲劳性能,考察了粘接表面的阳极化处理对修补结构的静态力学性能和疲劳性能的影响.结果表明,磷酸阳极化在铝合金表面形成多孔膜,复合材料补片修补胶接时胶粘剂能渗透进入阳极化铝合金表面的多孔膜,在粘接界面上形成一层过渡层,该过渡层的形成能有效提高其与复合材料的粘接性能,其粘接副的拉剪强度提高了104%;铝合金裂纹板胶接修理前的粘接表面的阳极化处理能大幅度地提高修复结构的静态强度和疲劳寿命,当用单向碳纤维/环氧复合材料补片单面修补时,修补结构的破坏强度为418.13MPa,恢复到完好板的93.42%;修补结构的疲劳寿命相对裂纹板延长了1.42倍,比未阳极化的修补板的疲劳寿命增加了27.59%.修补前的阳极化处理也使修补结构在一定周次疲劳后的剩余强度有所提高.