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509 results on '"Umezawa, T."'

6. Intense Lyman-alpha light source for ultra-slow muon generation

Author

Oishi, Y, primary, Adachi, T, additional, Saito, N, additional, Ikedo, Y, additional, Ishida, K, additional, Kanda, S, additional, Umezawa, T, additional, Kamioka, S, additional, Teshima, N, additional, Nakamura, J, additional, Nakamura, S, additional, Miyake, Y, additional, Iwasaki, M, additional, Wada, S, additional, and Shimomura, K, additional

Published
2023
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16. Study of DyBaCuO DC SQUIDs for low noise and high flux focusing

Author

Higashino, Y. and Umezawa, T.

Subjects
Superconducting quantum interference devices -- Research, Flux pinning -- Research, Josephson junction -- Usage, Business, Electronics, Electronics and electrical industries
Abstract

Molecular beam epitaxy is used to fabricate DyBaCuO direct current superconducting quantum interference devices (DC-SQUIDs) on MgO substrates containing step-edge Josephson junctions. The DC-SQUIDs exhibit RSJ-like current-voltage characteristics and periodic voltage modulation in the presence of an applied magnetic field at 77 degrees Kelvin. They also show excellent flux resolution.

Published
1995

27. CGC perpendicular recording media with CoCrPt-Si[O.sub2] alloy as granular layer

Author

Sonobe, Y., Tham, K.K., Wu, L., Umezawa, T., Takasu, C., Dumaya, J.A.H., Onoue, T., Leo, P., and Liau, M.

Subjects
Magnetic recorders and recording -- Analysis, Granular materials -- Magnetic properties, Thermal analysis, Business, Electronics, Electronics and electrical industries
Abstract

We investigated a new class of coupled granular/continuous (CGC) perpendicular media consisting of CoCrPt-Si[O.sub.2] granular layer with magnetically decoupled small grains. By changing the number of Co/Pd bi-layers in the continuous layer, the degree of exchange coupling can be systematically controlled. The introduction of Co/Pd multilayer improved the nucleation field ([H.sub.n) from -570 to--1670 Oe and [K.sub.u]V/[k.sub.B] T values from 67 to 97. Compared to the base granular media, the CGC media had 1 dB gain in signal-to-noise ratio (SNR) as well as 14 dB gain in write-ability (OW). Moreover, the output decay was reduced from -0.11 to -0.035 dB per decade. In CGC approach, a more appropriate strength of exchange coupling can be introduced that yields the significant improvement in both SNR and thermal stability. Index Terms--Continuous layer, exchange coupling, granular layer, perpendicular coupled granular/continuous (CGC) media, signal-to-noise ratio, thermal stability.

Published
2006

29. Interlaboratory comparison of delta 13C and deltaD measurements of atmospheric CH4 for combined use of data sets from different laboratories

Author

Umezawa, T., Brenninkmeijer, C., Röckmann, T., van der Veen, C., Tyler, S., Fujita, R., Morimoto, S., Aoki, S., Sowers, T., Schmitt, J., Bock, M., Beck, J., Fischer, H., Michel, S., Vaughn, B., Miller, J., White, J., Brailsford, G., Schaefer, H., Sperlich, P., Brand, W., Rothe, M., Blunier, T., Lowry, D., Fisher, R., Nisbet, E., Rice, A., Bergamaschi, P., Veidt, C., and Levin, I.

Published
2018

36. Improvement of flux density uniformity in giant magnetostrictive material foracoustic vibration element

Author

Wakiwaka, H., Umezawa, T., Yamada, H., Kobayashi, K., and Yoshikawa, T.

Subjects
Magnetic induction (Electromagnetic induction) -- Research, Magnetic materials -- Research, Finite element method -- Usage, Business, Electronics, Electronics and electrical industries
Abstract

This paper analyzes the magnetic circuit of acoustic vibration element using giant magnetostrictive material (AVEG). Such elements are used as the vibration source for undersea acoustic propagation of over 1000km. The analysis uses the finite element method. This paper also discusses two magnetic circuits (an initial and an improved model), developed to obtain an even flux density distribution in both the axial and radial directions of the vibrator. For both the initial and improved models, the paper defines, compares, and examines the flux density variations in the axial and radial directions within the vibrator.

Published
1993

37. カナダ・チャーチルにおける炭素・水素同位体比の観測から推定された大気中CH4濃度変動に対する北方湿地の寄与

Author

Prabir, K. Patra, Douglas, E. J. Worthy, Fujita, R., Morimoto, S., Umezawa, T., Ishijima, K., K. Patra, P., E. J. Worthy, D., Goto, D., Aoki, S., and Nakazawa, T.

Abstract

第7回極域科学シンポジウム/横断セッション:[IA] ニーオルスン観測拠点設立25周年記念横断セッション—北極域の科学（ニーオルスン、GRENE、ArCS)—12月2日（金）国立極地研究所1階交流アトリウム

Published
2016

42. Simulation of atmospheric N[subscript 2]O with GEOS-Chem and its adjoint: evaluation of observational constraints

Author

Wells, K. C., Millet, D. B., Bousserez, N., Henze, D. K., Chaliyakunnel, S., Griffis, T. J., Luan, Y., Dlugokencky, E. J., O'Doherty, Simon, Weiss, R. F., Dutton, G. S., Elkins, J. W., Krummel, P. B., Langenfelds, R. L., Steele, L. P., Kort, E. A., Wofsy, S. C., Umezawa, T., Prinn, Ronald G., Massachusetts Institute of Technology. Center for Global Change Science, and Prinn, Ronald G.

Abstract

We describe a new 4D-Var inversion framework for nitrous oxide (N[subscript 2]O) based on the GEOS-Chem chemical transport model and its adjoint, and apply it in a series of observing system simulation experiments to assess how well N[subscript 2]O sources and sinks can be constrained by the current global observing network. The employed measurement ensemble includes approximately weekly and quasi-continuous N[subscript 2]O measurements (hourly averages used) from several long-term monitoring networks, N[subscript 2]O measurements collected from discrete air samples onboard a commercial aircraft (Civil Aircraft for the Regular Investigation of the atmosphere Based on an Instrument Container; CARIBIC), and quasi-continuous measurements from the airborne HIAPER Pole-to-Pole Observations (HIPPO) campaigns. For a 2-year inversion, we find that the surface and HIPPO observations can accurately resolve a uniform bias in emissions during the first year; CARIBIC data provide a somewhat weaker constraint. Variable emission errors are much more difficult to resolve given the long lifetime of N[subscript 2]O, and major parts of the world lack significant constraints on the seasonal cycle of fluxes. Current observations can largely correct a global bias in the stratospheric sink of N[subscript 2]O if emissions are known, but do not provide information on the temporal and spatial distribution of the sink. However, for the more realistic scenario where source and sink are both uncertain, we find that simultaneously optimizing both would require unrealistically small errors in model transport. Regardless, a bias in the magnitude of the N[subscript 2]O sink would not affect the a posteriori N[subscript 2]O emissions for the 2-year timescale used here, given realistic initial conditions, due to the timescale required for stratosphere–troposphere exchange (STE). The same does not apply to model errors in the rate of STE itself, which we show exerts a larger influence on the tropospheric burden of N[subscript 2]O than does the chemical loss rate over short (< 3 year) timescales. We use a stochastic estimate of the inverse Hessian for the inversion to evaluate the spatial resolution of emission constraints provided by the observations, and find that significant, spatially explicit constraints can be achieved in locations near and immediately upwind of surface measurements and the HIPPO flight tracks; however, these are mostly confined to North America, Europe, and Australia. None of the current observing networks are able to provide significant spatial information on tropical N[subscript 2]O emissions. There, averaging kernels (describing the sensitivity of the inversion to emissions in each grid square) are highly smeared spatially and extend even to the midlatitudes, so that tropical emissions risk being conflated with those elsewhere. For global inversions, therefore, the current lack of constraints on the tropics also places an important limit on our ability to understand extratropical emissions. Based on the error reduction statistics from the inverse Hessian, we characterize the atmospheric distribution of unconstrained N[subscript 2]O, and identify regions in and downwind of South America, central Africa, and Southeast Asia where new surface or profile measurements would have the most value for reducing present uncertainty in the global N[subscript 2]O budget., United States. National Oceanic and Atmospheric Administration (Grant NA13OAR4310086), Minnesota Supercomputing Institute

Published
2015

44. Expression analysis of cellulose synthases that comprise the Type II complex in hybrid aspen.

Author

Osako, Y., Takata, N., Nuoendagula, Ishikawa, S., Umezawa, T., Taniguchi, T., Kajita, S., and Peter Mock, H.

Subjects
CELLULOSE synthase, CHROMOSOME duplication, ARABIDOPSIS thaliana, GENE expression in plants, PLANT cell walls, REVERSE transcriptase polymerase chain reaction
Abstract

Gene duplication in plants occurs via several different mechanisms, including whole genome duplication, and the copied genes acquire various forms and types. The cellulose synthase (CesA) family functions in cellulose synthesis complex (CSC) formation, which is involved in the synthesis of primary and secondary cell walls in plants. In the genome of Populus, 17 CesA have been annotated, and some of them appeared through whole genome duplication. The nucleotide sequence of the duplicated genes changed during subsequent evolution, and functional differentiation of genes might have occurred.To gain insight into the evolutionary fate of the duplicated CesA, expression analysis with quantitative reverse transcription polymerase chain reactions and promoter–reporter assays was performed on three duplicated gene pairs whose products have been reported to form a single CSC.Changes in expression of each gene at different developmental stages were detected and divergent expression patterns in different organs and tissues observed between the gene pairs. Among the tested genes, expression of PttCesA3‐C was apparently lower than that of its counterpart, PttCesA3‐D.The results suggest that the six CesA are approaching sub‐functionalisation or non‐functionalisation. Furthermore, the level of functionalisation may vary among the three pairs of genes, and functional specialisation of each CesA should have been achieved, at least partially, through differences in expression of genes. [ABSTRACT FROM AUTHOR]

Published
2019
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