Analytic Solutions of Teukolsky Equation in Kerr-de Sitter and Kerr-Newman-de Sitter Geometries

The analytic solution of Teukolsky equation in Kerr-de Sitter and Kerr-Newman-de Sitter geometries is presented and the properties of the solution are examined. In particular, we show that our solution satisfies the Teukolsky-Starobinsky identities explicitly and fix the relative normalization between solutions with the spin weight $s$ and $-s$.Comment: 24 pages, LaTe

Separation and recovery of carbon dioxide by a membrane flash process utilizing waste thermal energy

AbstractThe membrane flash process utilizing waste thermal energy was developed to realize an energy-saving technology and to substitute it for a conventional regenerator. The operating conditions of a membrane flash at high temperature were studied. The DEA concentration and the flashing pressure had optimum values to improve the performance and reduce the energy consumption for CO2 recovery. The petroleum refinery process and iron manufacturing process were proposed for candidate processes that actually had waste energy sources. Energy consumption and costs for CO2 recovery in the membrane flash and chemical absorption were estimated by custom-made program and discussed under the same conditions. The membrane flash was suitable for the CO2 emission sources that had high CO2 concentration independently of the plant scale. The chemical absorption was suitable for large-scale sources, even if the CO2 concentration was low

四肢の先天性麻痺・欠損を有する小児の四肢認知に関する研究

学位の種別: 課程博士審査委員会委員 : （主査）東京大学教授 水口 雅, 東京大学講師 篠田 裕介, 東京大学特任教授 井川 靖彦, 東京大学講師 武冨 修治, 東京大学講師 辛 正廣University of Tokyo(東京大学

Interplay between thermoelectric and structural properties of type-I clathrate K8Ga8Sn38 single crystals

We report structural, transport, and thermal properties of type-I clathrate K8Ga8Sn38 single crystals grown by the self-flux method. Single-crystal x-ray diffraction analysis confirmed that the guest K+ ion locates on the center in the tetrakaidecahedron composed of Ga and Sn atoms. The thermopower is largely negative,-200μ V/K at room temperature, irrespective of the flux used during growth Ga or Sn . The thermal conductivity κ(T) exhibits a large peak at 14 K. These observations in K8Ga8Sn38 are ontrasting with the splitting of the guest site and the glasslike behavior in κ(T) reported for type-I Ba8Ga16Sn30 although the free space for the guest is almost the same in both compounds. The electrostatic potential for the tetrakaidecahedron was calculated using the occupation probabilities of Ga ions in the three sites on the cage. It is found that the off-centered state is stabilized for the Ba2+ ions in Ba8Ga16Sn30 by the partial occupation of Ga anion in the 16i site while the on-center state for K8Ga8Sn38 is stabilized by the strongly preferred occupation of Ga anions in the 6c site. We conclude that the charge distribution on the cage is crucial for the splitting of the guest site into off-center positions in the tetrakaidecahedron of the type-I clathrate

Millimeter-wave communication system using photonic-based remote antennas for configurable network in dense user environment

Photonic-based millimeter-wave communication systems combined with conventional wireless systems have been proposed for the application in dense user environments like a large football stadium. By utilizing a narrow beam antenna for millimeter-wave asymmetric links, effective communication channels can be obtained

Public Field Trial of a Multi-RAT (60 GHz 5G/LTE/WiFi) Mobile Network

A public field trial showcasing an operational multi-Radio Access Technology (RAT) mobile network that was implemented in one of the largest shopping mall in Warsaw, Poland. The network supports novel 60 GHz 5G mobile access as well as legacy LTE and WiFi services All mobile access services of the network are interconnected via optical fiber to the data centers of a mobile network operator and an internet service provider. Fronthauling for the 60 GHz 5G hotspot radio access unit (RAU) and for LTE is realized by analog Radio-over-Fiber (RoF) via a fiber-optic distributed antenna system (DAS). The 60 GHz 5G radio access units (RAUs) for the enhanced mobile broadband (eMBB) use case and the WiFi access point (AP) are both backhauled via optical Gigabit Ethernet. The 60 GHz RAUs for the eMBB and hotspot use case feature 2D beam-switching and 1D beam-steering, respectively. Inter-RAT switching between the different mobile services with seamless user experience is achieved using a Mobile IP system with Fast Initial Link Setup (FILS)

Multi RAT (WiFi/ LTE/ 5G) Mobile Network featuring RoF Fronthaul, 60 GHz Beam-Switching and Mobile IP

We report on a public field trial demonstrating seamless handover in a multi Radio Access Technology mobile network supporting WiFi, LTE, and new 5G radio access in the 60 GHz band for full-duplex enhanced mobile broadband and 5G broadcast hotspots