Design of a semiconductor ferromagnet in a quantum dot artificial crystal

We present the theoretical design of quantum dot (QD) artificial ferromagnetic crystals. The electronic structure calculations based on local spin density approximation (LSDA) show that our designed QD artificial crystal from a structure comprising the crossing 0.104-micrometer-wide InAs quantum wires (an effective Kagome lattice) has flat band characteristics. Our examined QD artificial crystal has the ferromagnetic ground state when the flat band is half-filled, even though it contains no magnetic elements. The ferromagnetic and the paramagnetic state can be freely switched by changing the electron filling via a gate voltage.Comment: 12 pages, 3 figures included. For related information, visit http://www.brl.ntt.co.jp/people/tamura

On Precipitation Phenomena in Magnesium-Zinc Alloys

The ageing characteristics of magnesium-zinc alloys in the composition range from 3.2 to 19.0 wt.% zinc were studied at temperatures from 70° to 200°C mainly with X-ray diffraction methods and electron-microscopic observations with thin foils. The G.P. zones were confirmed to exist on the {1011} matrix planes. The transition phase on the {1010} matrix planes is MgZn´ indistinguishable from the hexagonal Laves phase MgZn₂. The effects of plastic deformation were examined with direct observations by thin foils. The formation of G.P. zones on the {1011} matrix plane was hindered by cold working after water quenching, while the rates of precipitation of the transition phase β´ and equilibrium phase β were accelerated

Aging Characteristics and Effects of Plastic Deformation on Precipitation in Al-4% Cu and Al-20% Ag Alloys with or without Trace Elements

The experiments have been carried out to examine the effects of plastic deformation and addition of small amounts of third elements on the aging process in Al-4%Cu and Al-20%Ag alloys by the X-ray Laue method, micro-hardness measurements, transmission electron microscopic studies and resistivity measurements. In binary Al-4% Cu alloys, the plastic deformation immediately after quenching retards the growth of G.P. (1) and G.P. (2), and accelerates the nucleation of the θ′ phase. In Al-20% Ag alloys, similar results are obtained. In undeformed ternary Al-Cu alloy, the retarding effects of third elements on aging become stronger in the order Be<Ti<Zr. In Al-Cu-Zr alloys, the plastic deformation much accelerates the growth of G.P. (1). The role of excess vacancies on aging and the interaction between dislocation and precipitates are discussed

Transmission Electron Microscopic Investigation on Recrystallization and Precipitation of Magnesium and Magnesium Alloys

Experiments have been carried out to examine aging characteristics, recrystallization phenomena and effects of plastic deformation after water-quenching on the precipitation of Mg-Th alloys in the composition range from 1.7 to 4.0 w/t% thorium as compared with pure magnesium, Mg-Zn and Mg-Al alloys mainly with electron microscopic observations in thin foils. In Mg-4.0% Th alloys, G. P. zones were confirmed to exist before the appearance of the transition phase Mg2Th in accordance with the result of measurements of electrical resistance. The presence of thorium in a magnesium alloy greatly retarded such processes as recovery and recrystallization. This slowing up process seems to be reflected in the slow precipitation rate of Mg-Th compounds. The effects of cold working on precipitation in these alloys are not simple but complex

Electron-Microscopic Investigation on Precipitation Phenomena in Aluminium-Zinc Alloys

The precipitation process, its relation with lattice defects and the effect of cold working on precipitation and grain boundary reaction in the aluminium alloys containing ll.2, 17.4, 28.3 and 40.8% zinc respectively were investigated by means of X-ray diffraction, hardness measurements and transmission electron microscopy. It was found that face-centered cubic transition precipitates were formed in granular shape in ll.2% or 17.4% zinc alloys and were plate-like in 28.3% zinc alloys. The plate-like transition precipitates were formed on {110} matrix planes, perhaps preferentially on the prismatic dislocation loops. The results are shown to be consistent with the hypothesis that in the quenched alloys precipitation occurs on prismatic dislocation loops that result from the condensation of quenched-in vacancies. In Al-28.3 and 40.8% Zn alloys, the grain boundary reaction is predominant at lower aging temperatures

An Improved DDS Tool with Versatile Cell-targeting Ability

Background/Aim: The aim of this study was to develop an improved drug delivery system (DDS) tool with enhanced versatility in the cell-targeting step using as Z-domain, a modified IgG binding domain of protein A from Staphylococcus aureus, as an IgG adapter domain. Materials and Methods: The chimera protein expression system composed of the Z-domain and chimeric cholesterol-dependent cytolysin mutant named His-Z-CDC(ss)IS was constructed in Escherichia coli. His-Z-CDC(ss)IS was purified by Ni-affinity chromatography, and its abilities for controlled pore formation, membrane binding, IgG binding, and target cell-specific delivery of liposomes carrying medicine were investigated. Results and Discussion: His-Z-CDC(ss)IS purified by Ni-affinity chromatography indicated pore-forming activity only under disulfide bond reducing conditions. His-Z-CDC(ss)IS also demonstrated an ability to bind both IgG and cholesterol-embedded liposomes via its Z-domain and domain 4, respectively. Furthermore, anticarcinoembryonic antigen (CEA) IgG-bound His-Z-CDC(ss)IS indicated effective delivery of liposomes carrying drugs to CEA-expressing cells. Conclusion: His-Z-CDC(ss)IS was revealed to be an improved DDS tool with enhanced versatility in cell targeting

農泊と観光 岡山県吉備中央町実践事例とともに

　「農泊」という言葉がツーリズムの世界で多用されるようになった。一般的には農家民宿のことではあるが、農林水産業に従事する家庭に滞在し、農山漁村の生活を体験することで日本の歴史・文化、民俗や食について深く学びながら地域住民との交流を楽しむものである。働き方改革の考え方が先行する西欧諸国で始まったグリーン・ツーリズムの発想の中で、リーズナブルな料金で利用できることからバカンスの中心的な役割を果たしてきた。これが今や日本においても教育旅行や訪日外国人旅行者のニーズにマッチし、全国的な展開が始まっている。その将来性について岡山県吉備中央町の例を参照しながら考察してゆく