Energy efficiency of transmit diversity systems under a realistic power consumption model

We compare the downlink energy efficiency of spatial diversity multiple transmit antenna schemes. We determine the minimum required transmit power for a given outage probability. Our analysis shows that antenna selection is in general the most energy efficient option as it requires a single radio-frequency chain. We also investigate the limiting distances up to which the antenna selection technique outperforms the transmit beamforming scheme for different numbers of transmit antennas

Crystallization of the Glasses in the Li2O-SiO2 System

Heterogeneity of the Li2O—SiO2 glass and the process of crystallization through heating were investigated by using the electron- and ordinary microscopic techniques. Under the electron microscope the separated droplet phases of about 100 Å in diameter were observed comprised in the matrix of the opales-cent glass composed of lithium trisilicate, while the parts of the colorless and transparent glass of lithium disilicate were also found to be slightly heterogeneous. In addition to above, the fact that the interfacial boundaries between two separated phases are not favorable for nucleation of the crystals was also confirmed. As a result of the differential thermal analysis, a small-scaled endothermic phenomenon assumed to be necessary for the atomic rearrangement was recognized just before the remarkable exothermic reaction ascribed to crystallization. Moreover, it is to be noted that devitrification of the glass rod accompanied with crystallization of lithium silicate and lithium metasilicate was markedly promoted in a short period of about two months

9 Å Mineral Included in the Weathered Biotite

A mineral species revealing the basal reflection at about 9 Å was found in some flakes of the altered biotite collected from the weathered granite cropping out in the vicinity of Hiroshima City and mineralogically investigated in detail

Alteration of Plagioclase in Granite during Weathering

Secondary minerals of plagioclase in spheroidally weathered granite of the Seranishi-cho, Hiroshima Prefecture, Japan have been examined by the technique of X-ray diffraction, X-ray fluorescence, DTA, TGA, pH measurements and electron microscopic observation. Spheroidally zoning of A, B and C owing to the difference of appearance at outcrop corresponds to the secondary mineral components, that is, allophane or allophane-like substance is found only in the zone C of core-part of granite and the zone B, metahalloysite and halloysite are predominant in the zones A and B that were intensely weathered parts, and kaolinite exists in the zones A and B, but lacks in the zone C. The crystallinity and grain-size of these kaolin minerals increase gradually from near central core-part toward the outer A zone. The probable al-terating sequence of plagioclase in the weathered granite of this district has been roughly assumed as follows: [Original table is skipped. For more details, please refer to the full text.

Energy efficiency of some non-cooperative, cooperative and hybrid communication schemes in multi-relay WSNs

In this paper we analyze the energy efficiency of single-hop, multi-hop, cooperative selective decode-and-forward, cooperative incremental decode-and-forward, and even the combination of cooperative and non-cooperative schemes, in wireless sensor networks composed of several nodes. We assume that, as the sensor nodes can experience either non line-of-sight or some line-of-sight conditions, the Nakagami-m fading distribution is used to model the wireless environment. The energy efficiency analysis is constrained by a target outage probability and an end-to-end throughput. Our results show that in most scenarios cooperative incremental schemes are more energy efficient than the other methods

Downlink Energy Efficiency Analysis of Some Multiple Antenna Systems

In this paper we compare the energy efficiency of different multiple antenna transmission schemes for long-range wireless networks, assuming a realistic power consumption model. We consider the downlink, between a base station and a mobile station, in which the Alamouti scheme, transmit beamforming, receive diversity, spatial multiplexing, and transmit antenna selection are compared. Our analysis shows that, for different types of base stations, outage probability requirements and spectral efficiencies, the transmit antenna selection scheme is in general the most energy efficient option. Although antenna selection is not the best in terms of outage probability, it becomes the most efficient in terms of overall power consumption as it requires a single radio-frequency chain to obtain spatial diversity

Evaluation of Mobility of Metal Elements in CCA-treated Wood for Efficient Recycling and Safe Disposal

この論文は国立情報学研究所の学術雑誌公開支援事業により電子化されました

Thermal Studies of Some Minerals, No. 3.: On Thermal Transformation of Antigorite in Air

The pulverized specimens of antigorite were subjected to the thermal treatments at various temperatures up to 1000°C in the air, and the effects of dehydration together with recrystallization were pursued by means of DTA, TGA, X-ray diffraction, infrared absorption spectroscopy and electron microscopy. The results obtained evidently suggest that emergence of the shoulder-like endothermic and exothermic peakes on the DTA curve is ascribed to destruction of the super-lattice structure of the original antigorite and production of the "mosaic olivine" during dehydration respectively and that under electron microscopic observation the recrystallized olivines with various shapes showing the specific relationships to orientation of the original mineral, controlled by the position, are discernible

Theoretical studies of the electrochromic response of carotenoids in photosynthetic membranes

Molecular orbital calculations are carried out on a number of carotenoids in the presence of an external charge and a constant electric field. The external charge is used to represent the strong permanent field that is believed to polarize carotenoids in photosynthetic membranes and thus to account for their linear response to the transmembrane potential. Our calculations show that the in vitro leads to in vivo spectral shifts of carotenoids (approximately 25 nm) can be produced by a charge in close proximity to the molecule. The interaction of the induced dipole moment with a constant field accounts for the observed magnitude of the electrochromic response in photosynthetic bacteria. The existence of a second pool of carotenoids that shows a significant (approximately 20 nm) wavelength shift but no electrochromic response can be explained by an external charge positioned near the center of the molecule that affects its absorption maximum while inducing essentially no dipole moment. The spectral shift for this pool is due to the induction of higher multipoles. These also account for discrepancies that arise when one attempts to account quantitatively for available experimental results on carotenoid band shifts in terms of classical electrochromic theory