High performance polymeric bipolar plate based on polypropylene/graphite/graphene/nano-carbon black composites for PEM fuel cells

In the present study, the effect of the addition of electrically conductive additives such as graphite, graphene, and high structure nano-carbon black on the manufacturing of polypropylene bipolar plates was studied. Furthermore, for achieving better dispersion of graphene in the matrix, maleic anhydride grafted polypropylene, as a compatibilizer, was utilized. An internal mixing device was used in order to mix additives with polypropylene matrix. Additionally, molding procedure was performed via the compression molding method. In-plane electrical conductivity as well as the flexural strength of various compositions were studied. The best composition of such composites possessed the electrical conductivity of 104.63 S/cm and flexural strength of 44.28 MPa. These values are higher than those designated by the United States Department of Energy for construction of bipolar plates.     

原位沉淀-焙烧法制备NiO/P-CNT复合材料及其电容性质

以聚吡咯衍生的碳纳米管作为载体,通过原位沉淀-焙烧相结合,合成了新型的氧化镍/聚吡咯衍生碳纳米管(NiO/P-CNT)复合材料。采用粉末X射线衍射、热重、能谱、扫描电镜、透射电镜、循环伏安以及恒流充放电测试对样品进行表征和分析。结果表明,须状NiO均匀地负载在聚吡咯衍生的碳管表面,构成了具有三维网络结构的复合物。基于这种特殊结构的优势,该复合物在电流密度为2A/g下的比电容为382F/g,NiO在复合物中电容贡献为441F/g,而NiO的比电容为351F/g。经过400圈充放电后,复合物的比电容保持在90%以上,而NiO的容量保持率为82.6%。因此,该复合电极材料较NiO具有更高的比电容和更好的循环特性。     

Tritium Isotope Separation by Multiphoton Dissociation of CF3CTCIF

A conception of the advanced water chemistry diagnosis system for detection of anomalies and preventive maintenance of system components is proposed. Extension of anomaly diagnosis knowledge and more reliable water chemistry data are indispensable to the advanced system. Then, correlations between water chemistry (conductivity and pH) change in reactor water and anomaly occurrence in the components of the feed water line are analyzed theoretically. These correlations are verified as applicable to extension of the diagnosis knowledge for anomalies in the components of the feed water line, such as resin intrusion, sea water Leakage at the condenser, and a breakdown in ion exchange capacity of resin at the condensate demineralizer.     

Recent advances in mapping environmental microbial metabolisms through 13C isotopic fingerprints

After feeding microbes with a defined ¹³C substrate, unique isotopic patterns (isotopic fingerprints) can be formed in their metabolic products. Such labelling information not only can provide novel insights into functional pathways but also can determine absolute carbon fluxes through the metabolic network via metabolic modelling approaches. This technique has been used for finding pathways that may have been mis-annotated in the past, elucidating new enzyme functions, and investigating cell metabolisms in microbial communities. In this review paper, we summarize the applications of ¹³C approaches to analyse novel cell metabolisms for the past 3 years. The isotopic fingerprints (defined as unique isotopomers useful for pathway identifications) have revealed the operations of the Entner–Doudoroff pathway, the reverse tricarboxylic acid cycle, new enzymes for biosynthesis of central metabolites, diverse respiration routes in phototrophic metabolism, co-metabolism of carbon nutrients and novel CO₂ fixation pathways. This review also discusses new isotopic methods to map carbon fluxes in global metabolisms, as well as potential factors influencing the metabolic flux quantification (e.g. metabolite channelling, the isotopic purity of ¹³C substrates and the isotopic effect). Although ¹³C labelling is not applicable to all biological systems (e.g. microbial communities), recent studies have shown that this method has a significant value in functional characterization of poorly understood micro-organisms, including species relevant for biotechnology and human health.     

低碳混凝土的技术理念与途径思考

从全球碳中和与可持续混凝土发展角度阐述了低碳混凝土的基本概念及全生命周期的减碳与碳汇核心技术理念.从原材料、混凝土设计、制备、施工、服役及再生利用等全生命周期过程提出了低碳混凝土的三大技术途径——直接减碳、间接减碳及碳汇技术，并分析了每个技术途径下的具体减碳技术路线.综述了混凝土的碳排放评价方法和准则，阐释了混凝土碳排放的生命周期评价方法 .提出了低碳混凝土未来的重点研究方向——开发新型胶凝材料以及碳汇技术.     

对中国碳纤维及其复合材料产业链发展现状的反思

简介了国际碳纤维及其复合材料的最新发展概况,并对中国从聚丙烯腈到碳纤维复合材料整个产业链和各关键链段的发展现状做了分析和反思。提出并论述了以下观点：要以系统论的思想发展碳纤维及其复合材料产业链;需从复合材料系统性降低成本来实现低成本化;深入了解与借鉴国际碳纤维行业的发展经验,调整我们的发展理念与方向;充分整合国际优质资源,建立较高水平的技术装备平台;转变观念,提升产学研的合作效益;借鉴国外成功经验,加强我国复合材料共享数据库建设;强化行业宏观管理,强力推进整个产业链的突破。最后提出创建碳纤维及其复合材料产业链联合会建议。     

水源水质受DEHP污染的粉末活性炭吸附处理工艺

采用含邻苯二甲酸二(2-乙基己基)酯(DEHP)的试验水样模拟城市取水水源发生DEHP水污染事故,测定粉末活性炭(PAC)对水样中DEHP的吸附性能,考察PAC炭种、吸附时间、DEHP初始浓度和PAC投加量等因素对DEHP的吸附量和脱除率的影响。试验结果表明:木屑PAC具有较大的比表面积,对DEHP具有良好的吸附效果,适用于DEHP水污染的应急处理。应急处理一般的DEHP水污染事故,DEHP污染浓度超标10～30倍时,PAC吸附DEHP的最佳条件为:吸附时间120 min,PAC投加量为20～80 mg/L,PAC对DEHP的吸附过程符合Henry等温式。     

我国高性能碳纤维产业发展现状与展望

对我国碳纤维产业的技术现状、主要生产厂家和市场需求进行了分析,就我国碳纤维产业发展面临的机遇与挑战进行了探讨,并针对碳纤维产业的未来发展提出了意见和建议.     

Low Temperature Hall Effect Investigation of Conducting Polymer-Carbon Nanotubes Composite Network

Polypyrrole (PPy) and polypyrrole-carboxylic functionalized multi wall carbon nanotube composites (PPy/f-MWCNT) were synthesized by in situ chemical oxidative polymerization of pyrrole on the carbon nanotubes (CNTs). The structure of the resulting complex nanotubes was characterized by transmission electron microscopy (TEM) and X-ray diffraction (XRD). The effects of f-MWCNT concentration on the electrical properties of the resulting composites were studied at temperatures between 100 K and 300 K. The Hall mobility and Hall coefficient of PPy and PPy/f-MWCNT composite samples with different concentrations of f-MWCNT were measured using the van der Pauw technique. The mobility decreased slightly with increasing temperature, while the conductivity was dominated by the gradually increasing carrier density.     

Combined generation and separation of hydrogen in an electrochemical water gas shift reactor (EWGSR)

Hydrogen rich gas, originating from fossil fuel reforming processes or biomass gasification, contains a significant amount of CO. Typically, the yield of H₂ is increased with subsequent water gas shift units, converting CO to CO₂ and additional H₂. This study describes a new reactor concept enabling the water gas shift reaction and the separation of the generated hydrogen in one process step by using electrical energy. This electrochemical water gas shift reactor applies a H₃PO₄-doped Poly(2,5-benzimidazole) membrane as electrolyte and carbon supported Pt or PtRu as anode catalyst. The reactor operation was investigated at 130 °C and 150 °C with a H₂ free anode feed stream of humidified CO and N₂. The experimental results show the feasibility of the reactor concept, as H₂ was generated at the cathode according to Faradays Law. Anodic PtRu led to lower power demands than Pt. The operation at the two temperatures showed that 130 °C results in a lower electrical power demand while generating an equal amount of H₂. The feasibility of the reactor was assessed using exergy efficiency analysis.