Study and performance test of 10 kW molten carbonate fuel cell power generation system

The use of high-temperature fuel cells as a power technology can improve the efficiency of electricity generation and achieve near-zero emissions of carbon dioxide.This work explores the performance of a 10 kW high-temperature molten carbonate fuel cell.The key materials of a single cell were characterized and analyzed using X-ray diffraction and scanning electron microscopy.The results show that the pore size of the key electrode material is 6.5 lm and the matrix material is a-LiAlO_(2).Experimentally,the open circuit voltage of the single cell was found to be 1.23 V.The current density was greater than 100 mA/cm^(2)at an operating voltage of 0.7 V.The 10 kW fuel cell stack comprised 80 single fuel cells with a total area of 2000 cm^(2)and achieved an open circuit voltage of greater than 85 V.The fuel cell stack power and current density could reach 11.7 kW and 104.5 mA/cm2 at an operating voltage of 56 V.The influence and long-term stable operation of the stack were also analyzed and discussed.The successful operation of a 10 kW high-temperature fuel cell promotes the large-scale use of fuel cells and provides a research basis for future investigations of fuel cell capacity enhancement and distributed generation in China.

Endurance Test of Biodiesel Fueled Tractor Engine

A diesel engine for tractor was tested for 250 hours of durability with biodiesel fuel of 100%. An engine test cycle was designed based on the ISO test code of off-road vehicle. Eight test conditions, combination of three engine speeds and eight engine loads, were applied to the engine endurance test, and the engine was operated for eight hours in a day. Power output, fuel consumption rate, exhaust gas quality and particulate matter （PM） were measured and discussed. For the extensive 250 hours of the tractor diesel engine endurance test no significant changes of power output, fuel consumption rate, exhaust gas quality and PM were monitored and authors could not find any difference in the engine patterns of the two fuels of BDF100 and light oil. During all the engine endurance test conditions, no abrupt stopping was encountered but because of temperature down by the cold season the endurance test could not carried out for some periods. PMs were collected and the average F＇M was 0.027 g/kw which was far below than Tier 4 diesel engine PM of 0.3 g/kw h defined by US EPA PM of the diesel engine clas,;. Overall even 100% biodiesel can be an alternative fuel for light oil for diesel engine operation with some considerations for cold sea：son use.

Quantitative evaluation of DNA damage caused by atmospheric and room-temperature plasma (ARTP) and other mutagenesis methods using a rapid umu-microplate test protocol for microbial mutation breeding

Mutagenesis is an important technique for microbial mutation breeding.As the source of mutations,DNA damage extent is a key indicator for the effectiveness of mutagenesis.Therefore,a rapid and easy DNA damage quantification method is required for the comparison of mutagenesis effects and development of mutagenesis tools.Here,we used the umu-microplate test system to quantitatively compare the DNA damage strength caused by atmospheric and room-temperature plasma(ARTP)and other traditional mutagenesis methods including:ultraviolet radiation(UV),diethyl sulfate(DES)and 4-nitroquinoline-1-oxide(4-NQO).The test strain of Salmonella typhimurium TA1535/pSK1002 was used to monitor the time-course profile of b-galactosidase activity induced by DNA damage caused by different mutagenesis methods using a microplate reader.The umu-microplate test results showed that ARTP caused higher extent of DNA damage than UV and chemical mutagens,which agrees well with the result obtained by SOS-FACS-based quantification method as reported previously.This umu-microplate test is accessible for broad researchers who are lack of the expensive FACS instruments and allows the quick quantitative evaluation of DNA damage among living cells for different mutagenesis methods in the study of the microbial mutation breeding.

Accelerated life-time test of MEA durability under vehicle operating conditions in PEM fuel cell

In this paper, a novel accelerated test method was proposed to analyze the durability of MEA, considering the actual operation of the fuel cell vehicle. The proposed method includes 7 working conditions： open circuit voltage （OCV）, idling, rated output, overload, idling-rated cycle, idling-overload cycle, and OCV-idling cycle. The experimental results indicate that the proposed method can effectively destroy the MEA in a short time （165 h）. Moreover, the degradation mechanism of MEA was analyzed by measuring the polarization curve, CV, SEM and TEM. This paper may provide a new research direction for improving the durability of fuel cell.

Preparation and Optimization of Porous Membrane Electrodes via Gradient Coating in Hydrogen Fuel Cell

Fuel cells are considered to be one of the ideal alternatives to traditional fossil energy conversion devices.Membrane electrodes are the core components in the hydrogen fuel cells.Our work reported the synthesis of the Pt/C catalysts with different Pt loading,and by changing the Nafion content,hot pressing temperature and hot pressing pressure,the catalyst coated membrane(CCM)spraying process was optimized.Moreover,the three-dimensional structure model of the single battery membrane electrode was studied quantitatively,and the porous membrane electrode with gradient distribution was fabricated under optimized processing conditions,with excellent electrical performance.

Graphene/carbon structured catalyst layer to enhance the performance and durability of the high-temperature proton exchange membrane fuel cells

In this study,nitrogen doped electrochemically exfoliated reduced graphene oxide and carbon black supported platinum(Pt/Nr EGO_(2)-CB_(3))has been prepared to enhance the performance and durability of hightemperature PEMFCs with lower Pt loading.On the one hand,Pt/Nr EGO_(2)-CB_(3)with the strong interaction between the Pt and nitrogen(N)prevent agglomeration of Pt particles and Pt particles is 5.46±1.46 nm,which is smaller than that of 6.78±1.34 nm in Pt/C.Meanwhile,ECSA of Pt/Nr EGO_(2)-CB_(3)decrease 13.65%after AST,which is much lower than that of 97.99%in Pt/C.On the other hand,the Nr EGO flakes in MEAac act as a barrier to mitigate phosphoric acid redistribution,which improves the formation of triple-phase boundaries(TPBs)and gives stable operation of the MEAacwith a lower decay rate of 0.02 mV h^(-1)within100 h.After steady-state operation,the maximum power density of Pt/Nr EGO_(2)-CB_(3)(0.411 W cm^(-2))is three times higher than that of conventional Pt/C(0.134 W cm^(-2))in high-temperature PEMFCs.After AST,the mass transfer resistance of Pt/Nr EGO_(2)-CB_(3)electrode(0.560Ωcm^(2))is lower than that in Pt/C(0.728Ωcm^(2)).

A Reliability-Based Strategy for the Analysis of Single Proton Exchange Membrane Fuel Cells

The development of power conversion systems based on fuel cells has been demanding reliability studies since the requirements associated with cost and durability of these technological products have become fundamental to their acceptance by the energy market. The experimental part of the reliability study presented in this work consisted of performing life tests with single proton exchange membrane fuel cells (PEMFCs). The proposed reliability analysis methodology covered the application of qualitative and quantitative techniques. In the qualitative approach, a Failure Mode and Effect Analysis was developed in order to identify and evaluate all potential failures associated with the operation of fuel cells. In the quantitative approach, a statistical analysis was applied to the sample data generated in long-term steady-state tests of these devices. A two-parameter exponential distribution was fitted to data and the maximum likelihood estimate for the mean time to failure (MTTF) of the fuel cells was calculated. It is important to point out that the tests performed under the scope of this study were the first long-term experiments performed with the fuel cells produced in the laboratories of IPEN-CNEN/SP, Brazil. Although the results indicated that fuel cell performance and durability were still at a level below the targets normally established for similar commercial devices, the improvement of the main components of PEMFCs has been the objective of several projects developed at the institute. Thus, the main benefit brought by this study is the proposed methodology, which can be implemented as part of a reliability growth analysis of the fuel cells and can be integrated into the design process of these devices.

Comparative In Vitro Osteoinductivity Study of CaP Ceramics (HA, α-TCP, β-TCP) using 10T1/2 Cells with Different Controls and Possible Correlations with Other Systems

In this study, we use a pluripotent mesenchymal stem cell (MSC) model, C3H/10T1/2, to evaluate three calcium phos-phate (CaP) materials, namely the hydroxyapatite (HA), α-tricalcium phosphate (α-TCP) and β-tricalcium phosphate (β-TCP). 10T1/2 cell was chosen as it has advantages over its counterparts in terms of ease of maintenance, free of ethical concerns and also more reproducible results. ALP enzymatic assay, RT-qPCR, DAPI staining and SEM were employed to assess the osteoinductivity of these materials. A good reference material which also acts as a scientific control is necessary for comparisons of results from different experimental batches and hence other materials such as titanium, Nunclon plastic surface, BD Falcon plastic surface and gold coated porous HA were also tested. The results show that ceramics induce a more sustained osteo-differentiation state as compared with plastics. Inductivity was found to be acting in descending order of strength with HA > β-TCP > α-TCP, which is reversed in terms of their impact on proliferation rate (HA TCP) and in vivo osteoinductivity in terms of incidence and quality of bone described previously (HA > β-TCP > α-TCP). These confirm the suitability of using 10T1/2 cells in cell culture assay of osteoinductivity.

细胞外囊泡在口腔鳞状细胞癌诊疗中的作用

背景:细胞外囊泡在不同的生理和病理生理条件下由多种细胞类型(包括肿瘤细胞)分泌到细胞外环境中,存在着广泛的生物学信号及细胞之间的信号传导。肿瘤衍生的细胞外囊泡可能会加剧癌症的进展、存活、侵袭和促进血管生成。目的:综述细胞外囊泡在口腔鳞状细胞癌诊疗中的研究进展。方法:由第一作者在Pub Med、万方和中国知网数据库中进行文献检索,关键词为“EVs,Oral squamous cell carcinoma,Diagnosis and treatment,Biopsy,Tissue engineering”及“细胞外囊泡,口腔鳞状细胞癌,诊疗,活检,组织工程”,最终纳入63篇文献进行分析。结果与结论:(1)在口腔鳞状细胞癌唾液活检中,细胞外囊泡作为肿瘤细胞与周围微环境间的信息传递工具,携带包括可溶性蛋白、脂质、DNA和RNA在内的多种生物分子,对口腔鳞状细胞癌的进展起着至关重要的作用,这些微小囊泡不仅在肿瘤的生长和扩散中扮演着关键角色,还提供了有关肿瘤生物学特性的重要信息。(2)唾液活检作为一种非侵入性诊断方法,通过分析其中的细胞外囊泡,可以为口腔鳞状细胞癌的早期诊断和靶向治疗开辟新的可能性。(3)研究发现,细胞外囊泡内含的生物活性分子,如micro RNAs(mi RNAs)和特定蛋白质,能作为口腔鳞状细胞癌的生物标志物,提高早期诊断的准确性。细胞外囊泡中的特定蛋白质如EHD2,CAVIN1,PF4V1和CXCL7等显示了作为新型预测性生物标志物的潜力。(4)此外,文章还强调了细胞外囊泡在口腔鳞状细胞癌治疗中的应用潜力,通过工程化改造,细胞外囊泡可以作为新一代纳米级药物输送系统,增强肿瘤靶向治疗的效率和特异性。(5)未来的研究将进一步深入探索细胞外囊泡在口腔鳞状细胞癌治疗中的作用及其机制,有望改善患者的生存率和生活质量。

Vehicles PEMFC Power System Mathematical Model for Integrated Design

In this paper, the mathematical dynamical model of a PEMFC （proton exchange membrane fuel cells） stack, integrated with an automotive synchronous electrical power drive, developed in Matlab environment, is shown. Lots of simulations have been executed in many load conditions. In this paper, the load conditions regarding an electrical vehicle for disabled people is reported. The innovation in this field concerns the integration, in the PEMFC stack mathematical dynamic model, of a synchronous electrical power drive for automotive purposes. Goal of the simulator design has been to create an useful tool which is able to evaluate the behaviour of the whole system so as to optimize the components choose. As regards the simulations with a synchronous electrical power drive, the complete mathematical model allows to evaluate the PEMFC stack performances and electrochemical efficiency.

面向个性化需求的燃料电池测试台价值评估方法

针对不同个性化需求的燃料电池测试台(fuel cell test bench,FCTB)难以评价和量化评估的问题,提出一种基于改进和声搜索算法的FCTB价值评估方法.针对不同FCTB的个性化需求,建立了FCTB综合评估指标体系;结合用户的个性化需求,采用模糊层次分析法分配指标权重,构建价值定量评估模型,将权重求取问题转换为约束优化问题;提出一种改进和声搜索算法对问题进行求解,通过设计解向量生成机制和参数自适应调整策略,用于提高传统和声搜索算法的求解效率和搜索能力.仿真结果表明,本文方法在计算效率和精度方面具有优势,并能够根据不同的需求特性实现对FCTB方案做出定量的价值评估.

活动门试验中土压力盒标定方法

为确保活动门试验结果的准确性,根据试验填土深度的不同,对一批相同型号的电阻式土压力盒进行了垂直方向上的分级加载和卸载标定,并考虑标定装置内壁摩擦力影响,修正了作用在土压力盒上的有效加载和卸载应力。通过对加卸载过程进行离散元模拟,证明有效加载和卸应力修正方法较为合理。标定试验结果表明,加载过程中微应变量-有效应力曲线呈线性变化,可使用线性函数拟合;卸载过程中微应变量-有效应力曲线存在明显的滞后现象,且滞后程度随有效加载应力的增大而增大,可使用单指数曲线拟合。标定土压力盒后,开展了填土试验,结果表明土压力盒不宜在压力过小或填土深度过小时使用。

不同气氛热处理对连续管道微波技术制备Pt/C催化剂氧还原性能的影响

车用质子交换膜燃料电池作为解决能源危机和环境恶化问题的重要能源转换装置,成本高、阴极氧还原反应动力学慢和长时间运行阴极催化剂稳定性差等问题成为制约其发展的主要原因。为解决质子交换膜燃料电池阴极催化剂长期稳定性差的问题,运用连续管道微波制备技术,制备铂载量为50%(质量分数)的催化剂,并分别采用氮氢混合气(20%H_(2))和空气两种不同气氛对Pt/C催化剂进行退火处理,通过表征和测试研究两种气氛热处理对其氧还原性能的影响。制备的Pt/C-300(20%H_(2))催化剂30000圈衰减测试后仍能保持71.4m^(2)/g和243mA/mg的高活性,实现了兼具高活性和高耐久性,为高氧还原性能催化剂的生产提供了一条有效可行的途径。

高温质子交换膜燃料电池动态性能测试教学实验设计

该文结合科研热点,设计了具有创新性和研究性的“高温质子交换膜燃料电池动态性能测试实验”。实验研究了阳极流动和死端模式下高温质子交换膜燃料电池在阶跃电流条件下的动态响应。从实验理论基础、实验平台搭建、性能测试方法及内容、实验结果探讨分析等方面,展示了科学研究的全过程。该实验旨在培养和提升学生的实验素养、科研能力、创新能力和实践能力。

燃料电池在无人机高压输电线路验电系统中的应用展望

随着无人机技术的不断发展,其在高压输电线路验电领域中的应用也日益广泛。燃料电池作为无人机飞行器的主要动力供能装置,具有续航能力强、能量密度高等多项应用优势。基于上述背景,针对燃料电池在无人机高压输电线路验电系统中的应用进行研究。分析燃料电池组成及其工作原理,并分别探讨其正、负极材料的储能特性,深入研究燃料电池结构模型。在此基础上,分别从效率高、污染性小两方面,分析燃料电池在无人机高压输电线路验电系统中的实际应用情况。

考虑时变效应的织构缸套润滑性能分析及试验研究

内燃机缸孔内的时变效应和气压变化对活塞环受力影响不可忽略,而织构形貌参数对发动机油耗性能的影响也有待深入研究。为此,构建考虑时变效应和缸内气体压力变化的织构化缸套-活塞环摩擦副的流体动压润滑模型,采用多重网格法求解模型获得润滑油膜压力分布规律,进而获得缸套-活塞环间的最小油膜厚度和摩擦力,并针对装配织构缸套的发动机开展台架试验。计算结果表明:缸内气体压力变化影响活塞环径向受力,时变效应使缸套-活塞环受挤压效应的影响;织构化缸套能够增加润滑油膜厚度、减少摩擦力,当微凹坑深度为4~7μm,织构面积密度较小如为5%、10%时,能够获得较佳的最小油膜厚度与摩擦力值。台架试验表明,与原发动机相比,装配织构缸套的发动机油耗性能明显改善,在中高转速下燃油耗降幅较为显著,油耗最大下降14.5%,而24 h机油耗减少26.48%。

基于反应状态原位测试的空冷型燃料电池运行参数分析

空冷型质子交换膜燃料电池内部反应状态是影响电池输出性能和稳定性的关键因素.通过研制空冷燃料电池反应状态的原位测试装置,实现电池温度和电流密度的实时测量,揭示氢气出口脉排间隔、氢气入口气压和阴极风速对电池性能的影响机制.研究表明:空冷电池中温度和电流密度分布不均,平均电流密度为500 mA/cm^(2)时,电池内温度极差达到20℃,电流密度极差达到400 mA/cm^(2).氢气出口脉排间隔越短、入口气压越大,氢气出口区域性能越好,分布均匀性越好,电流密度波动也越小,输出稳定性提高.如果阴极风速过低,电池局部温度高,温度分布均匀性降低;风速过高则导致生成水被吹走,质子膜含水量下降,电流密度分布均匀性变差.

应用于氢燃料电池的均温板传热性能多因素优化研究

为提升氢燃料电池温度的一致性以及散热效能,以均温板作为研究对象,基于理论计算和试验验证搭建均温板计算模型。选取影响均温板传热性能的冷凝段长度、布置角度、冷却工质类型和充液率4个重要因素进行4因素3水平正交试验,并利用极差分析得到各因素各水平对均温板热阻和蒸发段工作面最大温差影响的权重关系。结果显示:在均温板热阻方面,冷却工质类型影响最为显著,冷却工质充液率次之,冷凝段长度对其影响最弱;在均温板蒸发段工作面最大温差方面,冷却工质充液率影响最为显著,冷凝段长度次之,冷却工质类型对其影响最弱。结合分析得到全组最佳组合方案,其热阻值为0.175 K/W,蒸发段最大温差为1.2 K,传热性能表现最佳。

燃料电池耐久性优化方法研究

耐久性无疑是考量燃料电池工作性能的重要技术指标。本文介绍了目前燃料电池耐久测试的技术方法,分析了燃料电池耐久性的影响因素(燃料电池系统本体老化的影响和外部环境的影响),提出了从运行工况优化、系统控制策略优化两个方面改善燃料电池系统耐久性的实施路径,为燃料电池系统耐久性的提高提供了改进思路。

基于固态储氢与燃料电池耦合的车载氢能源系统建模与特性分析

探讨了一种使用金属氢化物储氢罐和质子交换膜燃料电池的车载氢能源系统,旨在通过数学建模和工况测试评估氢能源系统内部的热量耦合效应。基于热交换系统结构和换热特性提出了氢能源系统多物理场模型,又基于增程式燃料电池物流车运行工况进行了数值模拟和试验验证。结果表明,所提出的数学模型能准确表征车载氢能源系统的动态特性,功率响应与温度动态变化具有显著的一致性。借助热交换系统提供热量补充,低温条件下固态储氢罐释氢速度加快,提高氢能源系统的动态响应速度和能源利用效率。研究结果可用于基于固态储氢与燃料电池耦合的氢能源系统最优尺寸设计、温度控制和能量管理策略设计。