Intrinsic Spin Decay Length in Antiferromagnetic Insulator

We report intrinsic spin decay length of an antiferromagnetic insulator. We found that at an antiferromagnetic/ferromagnetic interface, a spin current generated by spin pumping is strongly suppressed by two-magnon scattering. By eliminating the two-magnon contribution, we discovered that the characteristic length of spin decay in NiO changes by two-orders of magnitude through the paramagnetic to antiferromagnetic transition. The spin decay length in the antiferromagnetic state is longer than 100 nm, which is an order of magnitude longer than previously believed. These results provide a crucial piece of information for the fundamental understanding of the physics of spin transport

Universal platform of point-gap topological phases from topological materials

Whereas point-gap topological phases are responsible for exceptional phenomena intrinsic to non-Hermitian systems, their realization in quantum materials is still elusive. Here we propose a simple and universal platform of point-gap topological phases constructed from Hermitian topological insulators and superconductors. We show that (d-1)-dimensional point-gap topological phases are realized by making a boundary in d-dimensional topological insulators and superconductors dissipative. A crucial observation of the proposal is that adding a decay constant to boundary modes in d-dimensional topological insulators and superconductors is topologically equivalent to attaching a (d-1)-dimensional point-gap topological phase to the boundary. We furthermore establish the proposal from the extended version of the Nielsen-Ninomiya theorem, relating dissipative gapless modes to point-gap topological numbers. From the bulk-boundary correspondence of the point-gap topological phases, the resultant point-gap topological phases exhibit exceptional boundary states or in-gap higher-order non-Hermitian skin effects.Comment: 6+6 pages, 4+4 figures, 1+0 tabl

Attempt to Generate Uniform Magnetic Field by Face-to-Face Magnet System Containing HTS Bulk Magnets

In order to develop small-scale nuclear magnetic resonance devices, the authors have been developing uniform magnetic fields in the space between the face-to-face settled magnetic poles which contain HTS bulk magnets. Since the NMR magnets in general require highly uniform field, it was expected to be difficult to form such homogeneous magnetic-field distribution with use of HTS bulk magnet, because the bulk magnets is characterized by its inhomogeneous magnetic field showing steep gradient. The authors modified the shape of the field distribution from convex to concave by attaching an iron plate on the pole surface. Then, the magnets were then settled face-to-face with various gaps, and the magnetic-field uniformity was estimated in the space. In order to detect the NMR signals, the field uniformity less than 1,500 ppm should be required after the former results on the hollow-type magnets. When we combined the concave and convex field distributions to compensate the uneven field distributions, the best uniformity reached 358 ppm in the 30 mm gaps, which exceeded the target value. In addition, we numerically simulated the feasible performance in this configuration, which resulted in obtaining the best uniformity of 30 ppm at 1.1 T at 7 mm distant from the pole surface in the gap of 30 mm. This result suggested that the concave and convex magnetic field distributions compensate the field uniformity with each other with keeping the magnetic field strength in the gap

Effective data collection scheme for real-spatial group communication over hybrid infra-ad hoc wireless networks

This paper presents an effective data collection scheme to provide group communications among appropriate members selected by each user’s geographic situation and preference (real-spatial information). When each user directly notifies central servers of user’s information via wireless network infrastructure (Wi-infra), message delivery latency and losses drastically increase due to the network congestion. Therefore, we employ representative nodes (RNs) selected in a distributed manner. The RN first collects the real-spatial information from neighboring nodes via an ad hoc network and then notifies the server via Wi-infra. From simulation experiments, our scheme can drastically reduce both message delivery latency and losses

Solar thermophotovoltaic using Al2O3/Er3 Al5O12 eutectic composite selective emitter

科研費報告書収録論文(課題番号:11555057・基盤研究(B)(2)・H11～H13/研究代表者:湯上, 浩雄/太陽熱光起電力による高温輻射-電力直接変換システムの開発

胎盤抽出物がヒト骨肉腫細胞株Saos-2の細胞増殖、I型コラーゲン産生およびALP分泌に及ぼす効果

Porcine placenta extract (P-placenta) is widely applied in medicine and cosmetics. However, few studies have examined the effect of the extract on the cellular behavior of the osteoblastic cell line Saos-2. Here, we demonstrated that P-placenta enhances the proliferation, collagen type I production, and alkaline phosphatase (ALP) secretion of Saos-2 in vitro. Proliferation of Saos-2 was assessed by MTT and DNA synthesisassays. Type I collagen production and ALP secretion were evaluated using enzyme-linked immunosorbent assay and ALP assays. The cells were treated with/without 20, 200 and 2000 g/ml of P-placenta for 24 h. We found that 200 g/ml P-placenta significantly induced the proliferation of Saos-2 and enhanced type I collagen production and ALP secretion. The results indicate that P-placenta controls the cellular behavior of osteoblasts,resulting in the secretion of early bone-related biomarkers

Feline Host Range of Canine parvovirus: Recent Emergence of New Antigenic Types in Cats

Since the emergence of Canine parvovirus (CPV-2) in the late 1970s, CPV-2 has evolved consecutively new antigenic types, CPV-2a and 2b. Although CPV-2 did not have a feline host range, CPV-2a and 2b appear to have gained the ability to replicate in cats. Recent investigations demonstrate the prevalence of CPV-2a and 2b infection in a wide range of cat populations. We illustrate the pathogenic potential of CPV in cats and assesses the risk caused by CPV variants