Proton exchange membrane fuel cells modeling based on artificial neural networks

To understand the complexity of the mathematical models of a proton exchange membrane fuel cell (PEMFC) and their shortage of practical PEMFC control, the PEMFC complex mechanism and the existing PEMFC models are analyzed, and artificial neural networks based PEMFC modeling is advanced. The structure, algorithm, training and simulation of PEMFC modeling based on improved BP networks are given out in detail. The computer simulation and conducted experiment verify that this model is fast and accurate, and can be used as a suitable operational model for PEMFC real-time control.     

Variable stoichiometry of proton pumping by the mitochondrial respiratory chain

The proton/oxygen stoichiometry and the mechanism of the proton pumping respiratory complexes in the mitochondrial respiratory chain have been central issues in bioenergetics for several years. Recently, a number of disagreements about stoichiometry have been resolved, and H+/O ratios of 6 (refs 1-3) or perhaps 8 (refs 4 and 5) for succinate oxidation are now accepted. Suggestions that the stoichiometry in mitochondria is intrinsically variable ('slip' in the pumps) have been made but the evidence has been neither strong nor direct. We now show by direct measurement in steady-state conditions that the H+/O ratio (measured as the charge/O ratio) for isolated mitochondria respiring on succinate varies from 6 at low membrane potential to 2.5-3 at membrane potentials of about 170 mV.     

盐酸羟氨参与的普鲁士蓝膜上质子掺杂行为

循环伏安法研究了氢离子对于普鲁士蓝修饰电极的普鲁士蓝膜具有掺杂作用,获得了掺杂过程的扩散控制的质子迁移可逆阳极和阴极电化学行为。盐酸羟氨具有一价正离子,与普鲁士蓝膜相互作用,抑制了质子的电化学行为。初始电位下,盐酸羟氨吸附量随静止时间的增加而增加,随富集时间的增加由于盐酸羟氨与质子的相互作用,呈现增加-平衡-降低的趋势。溶液pH对此过程的影响,峰电流表现为指数关系,峰电位表现为单个一价离子的能斯特响应。由于盐酸羟氨与质子相互作用,质子的迁移峰电流与盐酸羟氨浓度在2.08×10-3mol/l-8.33×10-8mol/l范围内对数呈直线关系,但由于受到多种因素干扰,不适合盐酸羟氨的分析测定。     

固体氧化物燃料电池电解质用离子导体

固体氧化物燃料电池以其高的能量转换效率和清洁的发电而被广泛研究.其中电解质—离子导体材料是影响固体燃料电池的效率和热力学稳定性的关键.作为所期望的电解质材料应满足以下要求(1)高的离子导电,(2)低的电子导电,(3)在使用条件一热力学稳定,(4)好的综合力学性能.在一些荧石相关结构和钙钛矿塑结构的氧化物中通过掺杂和取代形成氧空位可得到高的氧离子导电性.本文介绍了一些这类离子导体材料,并讨论了它们的特性.     

Pomeron和质子低Q^2结构函数

该文假定ｐｏｍｅｒｏｎ是质子的一种组分,并假定了南子和ｐｏｍｅｒｏｎ的线度尺寸。在双线度情况下讨论了ｅｐ深度非弹散射的作用机制,认为在小ｘ和０．３≤Ｑ＾２≤１ＧｅＶ＾２区域,ｅｐ深度非弹散射过程包括两个相互作用过程,一是虚光子和质子中夸克的相互作用,另一是虚光子以乔一介子的形式和ｐｏｍｅｒｏｎｅ及ｒｅｇｇｅｏｎ进行相互作用,并由此给质子结构函数在小ｘ和０．３≤Ｑ＾２≤１ＧｅＶ＾２区域的描述。     

质子交换膜中质子传递机理的分子模拟研究进展

利用分子模拟手段来解析质子交换膜中质子的传递规律,对于深化质子传递机理研究,指导高效质子交换膜的开发工作,从根本上提升燃料电池性能有着重要的意义。根据质子载体的不同类型,介绍了质子传递机理的分子模拟研究现状,指出了适用于分析Vehicle机理和Grotthuss机理的常用模拟方法,通过各模拟方法的比较,阐述了单一方法在模拟尺度和计算量方面的局限性,认为多尺度模拟法能够有效地解析影响质子传递的多重因素。在此基础上,指出开发高效、适用面广的多尺度模拟法是今后全面深入研究质子传递机理的有效途径。     

Evidence for spin-charge separation in quasi-one-dimensional organic conductors

Interacting conduction electrons are usually described within Fermi-liquid theory, which states that, in spite of strong interactions, the low-energy excitations are electron-like quasiparticles with charge and spin. In recent years there has been tremendous interest in conducting systems that are not Fermi liquids, motivated by the observation of highly anomalous metallic states in various materials, most notably the copper oxide superconductors. Non-Fermi-liquid behaviour is generic to one-dimensional interacting electron systems, which are predicted to be Luttinger liquids. One of their key properties is spin-charge separation: instead of quasiparticles, collective excitations of charge (with no spin) and spin (with no charge) are formed, which move independently and at different velocities. However, experimental confirmation of spin-charge separation remains a challenge. Here we report experiments probing the charge and heat current in quasi-one-dimensional conductors--the organic Bechgaard salts. It was found that the charge and spin excitations have distinctly different thermal conductivities, which gives strong evidence for spin-charge separation. The spin excitations have a much larger thermal conductivity than the charge excitations, which indicates that the coupling of the charge excitations to the lattice is important.     

带电导体之间的相互作用规律分析

从静电平衡状态下的导体性质出发,详细分析了导体与导体和导体与点电荷之间的相互作用规律,指出了并非同性带电导体一定相互排斥、异性带电导体一定相互吸引的客观规律;利用镜像法详细推证了点电荷与导体球之间的相互作用随距离的变化规律.