Magnesium-Based Materials for Hydrogen Storage: Microstructural Properties

Magnesium (Mg) is hydrogenated as core-shell-type hydride. Therefore, increase of absorption capacity to the theoretical hydrogen capacity is still one of the most important issues for the hydrogen storage materials. In this study, the procedure of the core-shell structure as well as effect of Al concentration in Mg on the growth MgH2 in Mg were investigated. MgH2 was formed on the surface as well as inside of unreacted Mg core. The inside MgH2 was formed in a granular form on Mg grain boundary and its size increased by applying plastic deformation. Thickness of the surface MgH2 and size of the internal MgH2 increased with an increase in hydrogenation time until the hydride surface was completely covered with MgH2. However, the growth of the surface and internal MgH2 came to a halt after the surface was covered with MgH2. From these results, supplying H from metal side was dominantly contributed for growth of the surface and internal MgH2 because diffusion rate of H in Mg was much higher than that in MgH2. In addition, the growth of internal MgH2 as well as control of surface MgH2 can contribute to the promotion of the complete hydrogenation of Mg-based hydrogen storage materials

Improving the Cycle-life of Naphthoquinone-based Active Materials by Their Polymerization for Rechargeable Organic Batteries

AbstractTo increase the cycle-stability of rechargeable batteries using an organic positive-electrode material, we synthesized a polymer from a 5,8-dihydroxy-1,4-naphthoquinone (DHNQ) skeleton, which potentially undergoes a four-electron transfer redox reaction. The polymeric material (PDHNQ) was synthesized by the condensation reaction between DHNQ and formaldehyde under acidic media conditions. The initial capacity of the electrode using the monomer (DHNQ), 193 mAh/g, quickly decayed to 56 mAh/g after 100 cycles. On the other hand, the electrode incorporating the prepared PDHNQ showed the higher initial discharge capacity of 256 mAh/g and a longer cycle-life, retaining about 133 mAh/g after 100 cycles

Ti–Pd Alloys as Heterogeneous Catalysts for Hydrogen Autotransfer Reaction and Catalytic Improvement by Hydrogenation Effects

Ti−Pd alloys were investigated as heterogeneous catalysts for hydrogen autotransfer reactions. This is the first reported study of alloys as catalysts for hydrogen‐borrowing reactions using alcohols. We improved the catalytic activities of alloys by increasing their specific surface areas via a hydrogenation−powdering process. The reactivities and selectivities of hydrogenated Ti−Pd alloys [Ti−Pd (Hy) ] were higher than those of non‐hydrogenated alloy catalysts in N‐alkylation by hydrogen autotransfer using alcohols. A plausible catalytic cycle is proposed based on control studies and deuterium labelling experiments

β-Catenin asymmetry is regulated by PLA1 and retrograde traffic in C. elegans stem cell divisions

Asymmetric division is an important property of stem cells. In Caenorhabditis elegans, the Wnt/β-catenin asymmetry pathway determines the polarity of most asymmetric divisions. The Wnt signalling components such as β-catenin localize asymmetrically to the cortex of mother cells to produce two distinct daughter cells. However, the molecular mechanism to polarize them remains to be elucidated. Here, we demonstrate that intracellular phospholipase A1 (PLA1), a poorly characterized lipid-metabolizing enzyme, controls the subcellular localizations of β-catenin in the terminal asymmetric divisions of epithelial stem cells (seam cells). In mutants of ipla-1, a single C. elegans PLA1 gene, cortical β-catenin is delocalized and the asymmetry of cell-fate specification is disrupted in the asymmetric divisions. ipla-1 mutant phenotypes are rescued by expression of ipla-1 in seam cells in a catalytic activity-dependent manner. Furthermore, our genetic screen utilizing ipla-1 mutants reveals that reduction of endosome-to-Golgi retrograde transport in seam cells restores normal subcellular localization of β-catenin to ipla-1 mutants. We propose that membrane trafficking regulated by ipla-1 provides a mechanism to control the cortical asymmetry of β-catenin

Intracellular Phospholipase A1 and Acyltransferase, Which Are Involved in Caenorhabditis elegans Stem Cell Divisions, Determine the sn-1 Fatty Acyl Chain of Phosphatidylinositol

Phosphatidylinositol (PI) is unique in the abundance of stearic acid at the sn-1 position. This fatty acid is thought to be incorporated through fatty acid remodeling. Here, we identified a phospholipase and acyltransferases involved in the fatty acid remodeling at the sn-1 position of PI and provide a link between the sn-1 fatty acid of PI and asymmetric cell division

Research and Design of a Routing Protocol in Large-Scale Wireless Sensor Networks

无线传感器网络，作为全球未来十大技术之一，集成了传感器技术、嵌入式计算技术、分布式信息处理和自组织网技术，可实时感知、采集、处理、传输网络分布区域内的各种信息数据，在军事国防、生物医疗、环境监测、抢险救灾、防恐反恐、危险区域远程控制等领域具有十分广阔的应用前景。 本文研究分析了无线传感器网络的已有路由协议，并针对大规模的无线传感器网络设计了一种树状路由协议，它根据节点地址信息来形成路由，从而简化了复杂繁冗的路由表查找和维护，节省了不必要的开销，提高了路由效率，实现了快速有效的数据传输。 为支持此路由协议本文提出了一种自适应动态地址分配算——ADAR（AdaptiveDynamicAddre...As one of the ten high technologies in the future, wireless sensor network, which is the integration of micro-sensors, embedded computing, modern network and Ad Hoc technologies, can apperceive, collect, process and transmit various information data within the region. It can be used in military defense, biomedical, environmental monitoring, disaster relief, counter-terrorism, remote control of haz...学位：工学硕士院系专业：信息科学与技术学院通信工程系_通信与信息系统学号：2332007115216