Work Function Measurement of Er-oxide/W(100) Surface by using of Photoemission Electron Microscope

A cathode material of a low work function is needed to achieve a high performance electron source. We measured the work function of W(100) surface modified with Er2O3 by using of photoemission electron microscope. The work function of Er-oxide/W(100) surface is measured to be 2.86eV. The work function of ZrO/W(100) thermal-field emission cathode has been reported to be 2.7~2.9eV. A work function of a cathode is generally estimated by Fowler-Nordheim plot (F-N plot). However, there are some ambiguities in this method. The work function measured by using of photoemission electron microscope (PEEM) is come from photo-electron emission phenomena. And the sample surface can be observed. These advantages on measurements make search of low work function materials easier. Therefore, we measure the work function of W(100) surface modified with Er2O3 by using of PEEM. The sample used in this experiment is a circular (100) oriented single crystal tungsten plate of 8mm in diameter and 0.1mm in thickness. A small amount of Er2O3 powder was dissolved in ethanol, and it is put on the sample surface. The sample was heated up to 2000K by electron bombardment in PEEM chamber of 10-8 Pa and the low work function surface was realized on the planar surface. The each PEEM images that the sample is irradiated with the light of wavelength from 300nm to 460 nm every 20nm are taken. In this study, the work function was estimated with the Fowler plot for the emission current density. However, the PEEM system cannot measure directly the emission current. Thus, we estimated the emission current density from the local brightness of the photoelectron image.The work function of Er-oxide/W(100) is measured in optical method by using PEEM. Fowler plot is used for estimating the work function of room temperature from PEEM data. The estimated work function of W(100) single crystalline surface modified with Er2O3 is 2.86eV

傾向スコアマッチング解析を用いた、全身麻酔術後の気管抜管後に発生する呼吸数変化を伴わない動脈血酸素飽和度低下の影響

BACKGROUND: It has been suggested that oxygen desaturation may be paradoxically related to the absence of an abnormal respiratory rate (RR) during acoustic respiratory rate (RRa) monitoring in a postoperative setting. We retrospectively compared the incidence of desaruration in patients without an abnormal RR with that in patients with an abnormal RR using propensity scorer matching. We also explored the factors contributing to oxygen desaturation without an RR monitoring alert. METHODS: We used ≤ 8 h postoperative data of the first 935 patients. Outcomes of patients with and without critical RR changes (RR > 30 or 2 min) (critical RR change vs. noncritical RR change) were first compared according to oxygen desaturation levels (SpO₂ 10 s). Multivariate analysis was used to determine oxygen desaturation-associated explanatory factors. RESULTS: Propensity score matching yielded 259 patients without critical RR changes and 259 patients with critical RR changes, respectively. Oxygen desaturation rates were higher in patients without critical RR changes [noncritical RR change vs. critical RR change: 39/220 (15.1%) vs. 16/243 (6.2%)]. An odds ratio and 95% CI for the noncritical RR change was 2.56 (1.38-4.55, P = 0.002). A critical change in the RRa was not observed in 576 patients; of these, oxygen desaturation was observed in 76 (13.2%) patients. Surgery duration (OR, 1.018 per 10 min increase; 95% CI, 1.002 to 1.035) was independently associated with oxygen desaturation without critical RR change. CONCLUSION: Postoperative oxygen desaturation paradoxically occurred more frequently in patients without critical RR changes, whose RR was monitored by the RRa under oxygen therapy. The duration of surgery may explain the possibility of postoperative oxygen desaturation without an RRa device alert.博士（医学）・甲第679号・平成30年3月15日Copyright © 2017 by authors and Via Medica This work is licensed under the Creative Commons Attribution International License (CC BY-NC-ND 4.0). https://creativecommons.org/licenses/by-nc-nd/4.0/The definitive version is available at " http://dx.doi.org/10.5603/AIT.a2017.0038

Statistics of seismic cluster durations

Using the standard ETAS model of triggered seismicity, we present a rigorous theoretical analysis of the main statistical properties of temporal clusters, defined as the group of events triggered by a given main shock of fixed magnitude m that occurred at the origin of time, at times larger than some present time t. Using the technology of generating probability function (GPF), we derive the explicit expressions for the GPF of the number of future offsprings in a given temporal seismic cluster, defining, in particular, the statistics of the cluster's duration and the cluster's offsprings maximal magnitudes. We find the remarkable result that the magnitude difference between the largest and second largest event in the future temporal cluster is distributed according to the regular Gutenberg-Richer law that controls the unconditional distribution of earthquake magnitudes. For earthquakes obeying the Omori-Utsu law for the distribution of waiting times between triggering and triggered events, we show that the distribution of the durations of temporal clusters of events of magnitudes above some detection threshold \nu has a power law tail that is fatter in the non-critical regime $n<1$ than in the critical case n=1. This paradoxical behavior can be rationalised from the fact that generations of all orders cascade very fast in the critical regime and accelerate the temporal decay of the cluster dynamics.Comment: 45 pages, 15 figure

Transport properties of Andreev polarons in superconductor-semiconductor-superconductor junction with superlattice structure

Transport properties of a superconductor-semiconductor-superconductor (S-Sm-S) junction with superlattice structure are investigated. Differential resistance as a function of voltage shows oscillatory behavior under the irradiation of radio-frequency (RF) waves with the specific frequency of 1.77 GHz regardless of the superconducting materials and the junction lengths. Experimental data are quantitatively explained in terms of the coupling of superconducting quasiparticles with long-wavelength acoustic phonons indirectly excited by the RF waves. We propose that the strong coupling causes the formation of novel composite particles, Andreev polarons.Comment: 4 pages, 4 figure

Visual completion of partly occluded grating in infants under 1 month of age

AbstractFour groups of eight infants (3 weeks of age on average) were each habituated to one of four displays consisting of a grating of either low (0.4 cpd) or high (1.2 cpd) spatial frequency, whose central portion was covered up with a horizontal occluder which was either narrow (1.33°) or broad (4.17°). These habituation displays are referred to as LN (low spatial frequency grating and narrow occluder), LB (low and broad), HN (high and narrow), and HB (high and broad) displays. Posthabituation-test displays consisted of a complete grating (CG) of the same frequency as the habituated grating along with a separate grating (SG) whose central portion was replaced with a black gap of the same height as the occluder in the habituation displays. Infants habituated to the LN display looked significantly longer at the SG than the CG display during posthabituation-test trials. Infants habituated to the LB and HN displays looked at the CG and SG displays, almost equally. In contrast, infants habituated to the HB display looked longer at the CG than the SG display. These results show that infants under 1 month of age can perceive the continuation of the grating behind the occluder, and that their visual completion on habituation displays can be evoked according to the interaction between the spatial frequency of the grating and the occluder height

Stereoselective E/Z photoisomerization of oxazolidinone functionalized enecarbamates: direct and triplet sensitized irradiation

Oxazolidinone-functionalized enecarbamates undergo diastereoselective E/Z photoisomerization upon direct and triplet sensitized irradiations with chiral/achiral sensitizers, showing that the enhanced product diastereoselectivity depends on the solvent and temperature

Hierarchical communities in the walnut structure of the Japanese production network

This paper studies the structure of the Japanese production network, which includes one million firms and five million supplier-customer links. This study finds that this network forms a tightly-knit structure with a core giant strongly connected component (GSCC) surrounded by IN and OUT components constituting two half-shells of the GSCC, which we call a\textit{walnut} structure because of its shape. The hierarchical structure of the communities is studied by the Infomap method, and most of the irreducible communities are found to be at the second level. The composition of some of the major communities, including overexpressions regarding their industrial or regional nature, and the connections that exist between the communities are studied in detail. The findings obtained here cause us to question the validity and accuracy of using the conventional input-output analysis, which is expected to be useful when firms in the same sectors are highly connected to each other.Comment: 38 pages, 17 figure