Effects of Antimony Oxide on the Characteristics of ZnO Varistors

The breakdown voltage, the upturn voltage, and the nonlinearity of the ZnO varistors are significantly influenced by the Sb₂O₃ and SiO₂ contents, as well as by the β→γ transition of the Bi₂O₃ phase. The lattice parameter of spinel is influenced by the coexisting Bi₂O₃ phase. Antimony oxide disperses into the powders of ZnO and other additives in the early stage of sintering, and finally gathers again as particles of spinel which may play an important role in the improvement of the nonlinearity by stressing the interfaces of two ZnO grains.     

Scanning electron microscopic structure of the prismatic layer in the Bivalvia

The shell structure of the Bivalvia has been observed with the use of optical and electron microscopes since the early 1900’s. The prismatic structure is one of the more attractive shell structures in bivalved mollusks. This structure is composed of the aggregation of polygonal prisms arranged densely. Each prism is made of small calcite crystallites arranged perpendicular to a growth shell surface. Organic materials, named organic sheaths, accumulate around prisms and stain well with heamatoxylin-eosin. The Bivalvia, which make prismatic structures, are divided into two groups. One group has the inner shell layer made up of a nacreous structure, and the other has the inner shell layer made up of a foliated structure. The aragonite prismatic layer and the prismatic layer are closely related to each other, as is the aragonite prismatic layer to the composite prismatic one.     

松油烯与马来酸酐的Diels-Alder反应的研究

研究了松油烯与马来酸酐的分子间Diels-Alder环加成反应和松油烯的异构转化行为。使用相对于α-松油烯过量的马来酸酐,相对于α-松油烯而言,在65～70℃二时有大约15％,在100～105℃下有38％,在135～140℃时有69％的松油烯异构转化率。同样在65～70℃和100～105℃温度下,矾土、活性白土、硅胶、离子交换树脂、对甲基苯磺酸催化下,大约有20％～77％的异构转化率。用异核远距离关联(HMBC)等核磁共振测试手法解析了环加成产物的结构,归属了各原子的化学位移。     

有机朗肯循环的研究进展

有机朗肯循环是一种被认为能有效利用低温热能的技术。科研工作者在不同方面（包括工质、膨胀机、换热器的影响、系统的优化）对有机朗肯循环系统效率的影响进行了大量的研究。本文针对不同热源的工质筛选、膨胀机的特点、系统循环优化以及换热器的影响方面进行了讨论和总结,为有机朗肯循环系统的实际应用提供参考。     

化学蓄热材料的开发与应用研究进展

作为化学能与热能相互转换的核心技术,化学反应蓄热是21世纪最为重要的储能技术之一。与传统的潜热储能方式相比较而言,化学反应蓄热的能量储存密度有着数量级的提升,其在工作温度范围以及材料稳定性上的优势显著。本文针对金属氢氧化物、金属氢化物、金属碳酸盐、结晶水合物、金属盐氨合物等几种当前主要的化学蓄热材料,重点阐述了各自的应用机制和工作条件,分析了各种材料的研究现状和亟需解决的科学及应用问题,指出复合以及掺杂型材料的优化制备是化学蓄热技术未来发展的主要方向。     

Co-Al基三元系中B2相的溶解度间隙与稳定性

Information on phase equilibria in the Co-Al based systems which are related to some magnetic and heat resistance materials is important for their microstructural control. Recently, it was proposed with a theoretical calculation on electronic band structure that some Heusler-type alloys Co2 XAl (X: Cr and Mn) should be a new type of spinelectronic materials so-called half-metallic ferromagnet. In the case of the Co2CrAl, however, magnetic properties expected from the theoretical work can not been experimentally obtained and the reason has been still unknown. On the other hand, a tunne- ling magnetoresistance (TMR) effect due to the half-metallic properties was reported in Co2 (Cr0.6 Fe0.4 ) Al alloy, but not the Co2CrAl alloy. In the present paper, it is reported that this discrepancy with the theoretical work in the Co2CrAl alloy is bought about by phase separation between A2 and B2 phases, and that the substitution of Fe for Cr can suppress the precipitation of A2 phase in the B2 phase. Such a phase separation is originally due to the miscibility gap between CoAl and Cr formed in the Co-Al-Cr ternary system as well as that reported by Hao et al. in the Ni-Co-Al-Fe system.     

Influence of casting surfaces on fatigue strength of ductile cast iron

Quantitatively evaluating the fatigue strength of ductile iron (DI) with casting surfaces involves several complicated factors such as surface roughness, transition of microstructures from surface to interior, several types of defects and residual stresses. Tension–compression fatigue tests have been performed using DI having casting surfaces composed of a ferritic structure, a ferrite‐pearlitic structure and a pearlitic structure. Residual stresses were relieved by annealing in order to separately evaluate each factor. The parameter model was applied for quantitative evaluation of fatigue strength. Surface roughness was considered to be mechanically equivalent to a defect, and the effective defect size due to the interaction between the surface roughness and a defect was defined. The present study proposes a method of evaluating the maximum defect size using statistics of extremes and the lower bound of the scatter of fatigue strength, for practical design.     

Comparative study of behavior of inhaled samarium and cerium in mice

Distribution of Sm and Ce in mice was investigated after inhalation exposure to their oxide particles of 5 μm diameter and 15 mg/m3.Sm and Ce were mainly distributed in lung,their concentrations decreased with passing time,and their concentrations in lung were correlated with exposure periods.Concentrations of Ce were lower than that of Sm in each point.Sm was also distributed in the other organs and bone but Ce was scarcely detected.These results suggest that the behaviors of Sm and Ce inhaled were different,although their chemical properties are similar.     

含有回收材料的GRC的性能

由于对环境的关注和废料的处理问题,近些年对工业废料进行了积极的回收.回收废料作为混合材被广泛应用在GRC混凝土中.本文对使用了工业废料混合材的GRC的基本物理性能和耐久性所进行了研究.我们的结论是:粉煤灰、矿渣和硅灰的使用可以提高GRC的耐久性.在这些结论的基础上,提出将耐久性好的GRC配合比与回收废料结合在一起.经加速老化试样的抗折强度相当于暴露在日本室外10年时间的试件的强度,高于最初的强度,等于传统GRC的强度.由于火山灰反应消耗了基体中的Ca(OH)2,分别通过热分析和X射线衍射分析,在加速老化的含有矿渣和硅灰的砂浆中没有发现Ca(OH)2.     

Description and Phylogenetic Position of Dinosaur Eggshells from the Luanchuan Area of Western Henan Province, China

Here, we examine 145 dinosaur eggshells from a new fossil locality in the Qiupa Formation (Upper Cretaceous) of the Luanchuan area in western Henan Province, China. The eggshells display elongatoolithid macro- and microstructures, including ridges and nodes on the outer surface, two ultrastrncturai layers, and an undulatory boundary between the mammiilary and continuous layers.A phylogenic analysis shows that the Luanchuan eggshells belong to the ooclade Eiongatoolithidae.Within Elongatoolithidae, the thickness ratio of the mammillary layer to the entire eggshell, and the porosity of the Luanchuan eggshells are comparable to the oogenera Macroolithus and Elongatoolithus. There is no direct evidence for the taxonomic identity of the Luanchuan eggshells;however, they were likely laid by oviraptorids based on their phyiogenetic position and their similarities with known oviraptorid eggs.