Magnetic exchange coupling in cuprate-analog d9d^9 nickelates

Motivated by the recent discovery of superconductivity in doped NdNiO$_2$, we study the magnetic exchange interaction $J$ in layered $d^9$ nickelates from first principles. The mother compounds of the high-$T_{\rm c}$ cuprates belong to the charge-transfer regime in the Zaanen-Sawatzky-Allen diagram and have $J$ larger than 100 meV. While this feature makes the cuprates very different from other transition metal oxides, it is of great interest whether layered $d^9$ nickelates can also have such a large $J$. However, one complexity is that NdNiO$_2$ is not a Mott insulator due to carrier doping from the block layer. To compare the cuprates and $d^9$ nickelates on an equal basis, we study RbCa$_2$NiO$_3$ and $A_{2}$NiO$_{2}$Br$_2$ ($A$: a cation with the valence of $2.5+$), which are recently designed theoretically by block-layer engineering. These nickelates are free from the self-doping effect and belong to the Mott-Hubbard regime. We show that these nickelates share a common thread with the high-$T_{\rm c}$ cuprates in that they also have a significant exchange interaction $J$ as large as about 100 meV.Comment: 10 pages, 3 figure

Development of 3-Cylinder Rotary Compressor for Large Capacity

The authors have developed a large capacity rotary compressor with compact size and low vibration. Recently, we have strong requirements for larger capacity without changing the compressor shell diameter. Considering for larger capacity in conventional 2-cylinder rotary compressor inverter type, there are issues such as high vibration, big sound. As the solution for these problems, we have developed 3-cylinder rotary compressor inverter type which have different compression process of 120 ° phase per revolution for each cylinder. The developed compressor achieves a capacity target, proves one-quarter vibration level comparing with 2-cylinder rotary compressor and ensure the improvement of reliability result. We have been manufacturing the world largest capacity of new rotary compressor and have been launching into the market since September 2020. This new model has successfully attained more large capacity with same shell diameter as our previous large capacity of 2-cylinder rotary compressor inverter type. This new model adopt some new technologies such as the 3-cylinder design for balancing rotation torque, the multi discharge valve structure, the integrated bearing with partition plate and the new wide-range motor. By these technologies, the outdoor units of multiple air conditioner for buildings (Variable Refrigerant Flow-VRF) can achieve a large capacity 20 HP (56kW) with applying one compressor unit only

Development of Large Capacity And High Efficiency Rotary Compressor

The authors had studied some elemental technologies to realize the large capacity and high efficiency in rotary compressor in order to achieve energy and material resource savings as well as in weight reduction of heat pump systems. Those elemental technologies are the cylinder dimension optimization, the new discharge structure, the divided vane structure, and the compatibility between sliding loss reduction and securing reliability in journal bearings. The new discharge structure is a structure in which two discharge ports are installed per cylinder. The discharge ports are designed with different in cross-sectional area and the responsiveness of each discharge valve is also optimized. By applying the new discharge structure, discharge losses drastically reduced during compression process. The divided vanes structure which splits the vane in the axial direction to reduce force due to the pressure difference per each vane enables to avoid the increasing risk at local contact surface pressure on vane. The journal bearing designs are optimized by using structural analysis. Enhanced shaft stiffness and appropriate journal bearing design contribute to sliding friction reduction and high reliability assurance. By adopting those technologies, we succeeded in developing a new compressor that can increase to the maximum refrigeration capacity 20 HP [60kW]. Compared to our conventional large model, the new model has 1.7 times larger maximum capacity, and about 6 % higher COP ratio in most operation condition range. Moreover, by the more compact and lighter weight of 38.2 kg, the new one has contributed to resource saving and weight reduction of the heat pump unit system. We commercialized this developed compressor for our latest air-cooled module heat pump unit “Universal Smart X Edge Series” which expanded up to 70HP in rated cooling capacity and achieved “IPLV 6.0” at 60 HP heat pump unit systems

Application of precise neutron focusing mirrors for neutron reflectometry: latest results and future prospects

超精密中性子集束ミラーによる電極界面のナノ構造解析技術の実用化 --測定精度の劇的な向上に向けた大きなマイルストーン--. 京都大学プレスリリース. 2020-10-28.Neutron reflectometry (NR) is a powerful tool for providing insight into the evolution of interfacial structures, for example via operando measurements for electrode–electrolyte interfaces, with a spatial resolution of nanometres. The time resolution of NR, which ranges from seconds to minutes depending on the reflection intensity, unfortunately remains low, particularly for small samples made of state-of-the-art materials even with the latest neutron reflectometers. To overcome this problem, a large-area focusing supermirror manufactured with ultra-precision machining has been employed to enhance the neutron flux at the sample, and a gain of approximately 100% in the neutron flux was achieved. Using this mirror, a reflectivity measurement was performed on a thin cathode film on an SrTiO3 substrate in contact with an electrolyte with a small area of 15 × 15 mm. The reflectivity data obtained with the focusing mirror were consistent with those without the mirror, but the acquisition time was shortened to half that of the original, which is an important milestone for rapid measurements with a limited reciprocal space. Furthermore, a method for further upgrades that will reveal the structural evolution with a wide reciprocal space is proposed, by applying this mirror for multi-incident-angle neutron reflectometry

Optimal Collection of Peripheral Blood Stem Cells By Assessing CD34+ cells in Cancer Patients Administered with G-CSF after Chemotherapy

The mobilization of stem cells from bone marrow to peripheral blood in can-cer patients administered with recombinant human granulocyte colony-stimulat-ing factor (G-CSF) were examined. Eight patients were injected with G-CSF subcutaneously at a dosage of 250 μg/body daily from WBC nadir by chemother-apy. The quantity of peripheral blood stem cells (PBSC) was assessed by the colony assay of CFU-GM, which peaked on the third to fifth day after the com-mencement of daily G-CSF administration. G-CSF significantly amplified the amount of PBSC in five of eight patients. These results suggest that a sufficient amount of stem cells for transplantation (1.7 × 105-5.4 × 105 CFU-GM/Kg) can be obtained in such cases if 5 L of blood was processed by leukapheresis. A flow cytometry analysis revealed that CD34+ cells measured by mononuclear cell gat-ing coincidentaly increased with the peak of CFU-GM and therefore their assess-ment may serve an useful index for rapid monitoring of PBSC. And, days 3-5 after the commencement of G-CSF injection may be the optimal timing for PBSC collection