彩色电子纸研究最新进展

Amazon Kindle的出现在全球掀起了电子纸的热潮,黑白电子纸显示技术正在不断完善.随着电子纸市场需求的增加,研制新型彩色电子纸显示技术成为众多科研人员关注的焦点.本文介绍了日本千叶大学北村研究室在彩色电子纸显示技术研发上所取得的最新进展,针对基于电泳显示和色粉移动方式的彩色电子纸技术做了详细说明.     

Flaking failure originating from a single surface crack in silicon nitride under rolling contact fatigue

Flaking failure caused by surface cracks of silicon nitride ceramic bearings has been investigated from the viewpoint of the ring crack model. However, the relation between surface and subsurface cracks under rolling contact fatigue is not fully understood. In this investigation subsurface cracks branching from an initial surface crack were observed in detail, and the process of flaking failure was investigated. The specimens were observed prior to the separation of the surface layers and it was found that the initial surface cracks grew vertically to the surfaces and did not curve as predicted by the ring crack model. Subsurface cracks branched from the single surface cracks and grew in a direction parallel to the surface. They grew in both the same and the opposite directions to the ball movement, with small upward and downward branches. These subsurface cracks grew prior to the semi‐circular surface cracks. From these observations it was concluded that the flaking failures are not caused directly by the surface cracks, but by the subsurface cracks that branch from them.     

Effects of homogenisation conditions on the physical properties of high-fat ice cream

The effect of homogenisation pressure on the physical properties of high-fat ice cream was investigated. Nonhomogenised ice cream was hard, with low resistance to meltdown, and ice crystals grew rapidly therein. Fat globule networks were not formed in the nonhomogenised ice cream. The ice cream homogenised at 5 MPa or more was harder and showed a higher resistance to meltdown. Ice crystals in the ice cream homogenised at 5 MPa or more grew slowly. The physical properties of each ice cream varied with homogenisations from 5 to 25 MPa and could be controlled by homogenisation pressure.     

Phase Equilibrium in the System PbO-TiO2–ZrO2

Phase equilibrium relations in the system PbO–TiO₂–ZrO₂ were studied by quenching in the range where the PbO content is 50 mole % and more. Isotherms were examined at 1100°, 1200°, and 1300°C and tie lines were determined between the liquid and solid solution in equilibrium. The incongruent melting point of PbZrO₃ was 1570°C and the equilibrium between liquid, PbO-type solid, and PbZrO₃ is peritectic. Pb(Zr,Ti)O₃ solid solutions containing more than 14 mole % PbZrO₃ decomposed to liquid, ZrO₂, and Pb(Zr,Ti)O₃ and the decomposition temperature rises from 1340° to 1570°C with increasing PbZrO₃ content. The system PbTiO₃–PbZrO₃ should not be treated as a binary, but as a section of the ternary system.     

An analysis of land use/cover change in Indonesia

The phenomena of land use/ change were evaluated by using a remote sensing approach in a case study in Yogyakarta, Indonesia. The index of changes, which was calculated by the superimposition of land use/ images of 1972, 1984, and land use maps of 1990, were introduced to analyse the pattern of change in the area. The results demonstrated that the pattern of land use/ change in the study area was that of paddy coverage to open/ land to settlement. The annual growth ratios of new settlements to absorb paddy coverage, mixed vegetation, and open/ land were 16 per cent, 20 per cent, and 64 per cent respectively. The larger the percentage of the paddy coverage, the higher the tendency for settlement growth to absorb the paddy coverage, and the larger the percentage of open/ land, the higher the tendency for settlement growth to absorb open/ land. Settlement growth had a high correlation with road accessibility. The highest settlement growth was distributed mostly in suburban areas between 200 and 400 m from secondary roads. Without intelligent intervention by the government and public awareness, the loss of these agricultural land cannot be stopped and will jeopardize the local and regional economy.     

Correct self-consistent small signal analysis of peniotron mode in rotating electron-beam devices

In this paper, we make clear that already reported self-consistent small signal analyses of gyrotron and peniotron modes in rotating electron devices is applicable only for a gyrotron mode, and not for a peniotron mode. Here, we propose the new correct self-consistent small signal analysis of the peniotron mode and show some of our numerical results which indicate the distinct characteristics of the peniotron modes from those of the gyrotron ones     

Mesenchymal stem cells-derived extracellular vesicles as ‘natural’ drug delivery system for tissue regeneration

Mesenchymal stem cells (MSCs) have abilities to mediate tissue protection through mechanisms of anti-apoptosis, anti-oxidative stress and anti-fibrosis as well as tissue regeneration through mechanisms of cell proliferation, differentiation and angiogenesis. These effects by MSCs are mediated by a variety of factors, including growth factors, cytokines and extracellular vesicles (EVs). Among these factors, EVs, containing proteins, mRNA and microRNAs (miRNA), may carry their contents into distant tissues with high stability. Therefore, the treatment with MSC-derived EVs may be promising as ‘natural’ drug delivery systems (DDS). Especially, the treatment of MSC-derived EVs with the manipulation of specific miRNAs expression has been reported to be beneficial under a variety of diseases and tissue injuries. The overexpression of specific miRNAs in the EVs might be through pre-loading method using the gene editing system by plasmid vector or post-loading method to load miRNA mimics into EVs by electroporation or calcium chloride-mediated transfection. Despite current several challenges for clinical use, it should open the next era of regenerative medicine for a variety of diseases. In this article, we highlight the therapeutic potential of MSC-derived EVs as ‘natural’ DDS and current challenges.     

利用选择性浸出和沉淀从高磷钢渣中提取磷

摘要：使用高磷铁矿石冶炼所产生的高磷钢渣被视为一种磷资源。为了回收高磷钢渣中的磷,研究采用了选择性浸出和沉淀的方法,对不同P2O5含量的高磷钢渣进行了研究。结果表明：高磷钢渣中P2O5主要富集在2CaO·SiO2-3CaO·P2O5固溶体中;pH值为5.0时高磷钢渣中大部分固溶体被溶解分离,磷溶出率超过81.0%,而铁溶出率低于6.0%,实现了选择性浸出;浸出后的低磷残渣可作为冶金熔剂循环使用;升高浸出液pH值后,磷酸根离子形成沉淀;回收的沉淀物中P2O5质量分数达到23.9%,可作为磷肥使用。通过本工艺,高磷钢渣中磷能被有效分离及提取,实现了资源化利用。