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Dengue fever (DF) and leptospirosis are serious public problems in tropical regions, especially in Manila, the Philippines. In attempting to understand the causes of DF and leptospirosis seasonality, meteorological factors have been suspected, but quantitative correlation between seasonality and meteorological factors has not been fully investigated. In this study, we investigated correlation of temporal patterns of reported numbers of laboratory-confirmed cases of both DF and leptospirosis with meteorological conditions (temperature, relative humidity, rainfall) in Manila. We used time-series analysis combined with spectral analysis and the least squares method. A 1-year cycle explained underlying variations of DF, leptospirosis and meteorological data. There was a peak of the 1-year cycle in temperature during May, followed by maxima in rainfall, relative humidity and number of laboratory-confirmed DF and leptospirosis cases. This result suggests that DF and leptospirosis epidemics are correlated not only with rainfall but also relative humidity and temperature in the Philippines. Quantifying the correlation of DF and leptospirosis infections with meteorological conditions may prove useful in predicting DF and leptospirosis epidemics, and health services should plan accordingly.
Seyfert galaxies often have extended emission line regions around their nucleus. We started an observation program of optical tridimensional spectroscopy for circumnuclear regions of nearby Seyfert galaxies to investigate the ionization source of the gas of just vicinity(typically several hundred pc) of nucleus.
A narrow-band imaging observation of the Seyfert galaxy NGC1068 was made in the Fabry-Perot mode of the Kyoto 3D Spectrograph attached to the 188cm telescope of the Okayama Astrophysical Observatory. We observed at wavelengths of Hα, [S ii]λ6716, [S ii]λ6731 and adjacent continua of the respective lines with a “tunable filter”, i.e. a gap-scanning etalon with a spectral resolution of 20 Å.
Infrared Imaging Surveyor (IRIS, officially Astro-F) is a satellite which will be launched in the winter of 2003. The main purpose of the IRIS mission is an all sky survey in the mid- and far-IR with a flux limit much deeper than that of IRAS. In order to examine the performance of the survey and to find a suitable set of bandpasses for tracing galaxy evolution and picking up protogalaxy candidates as effective as possible using IRIS, we estimated the FIR galaxy counts based on a simple model with various sets of cosmological parameters and evolution types.
The aim of this study was to evaluate the dosimetric aspects of whole brain radiotherapy (WBRT) using an irregular surface compensator (ISC) in contrast to conventional radiotherapy techniques.
Treatment plans were devised for 20 patients. The Eclipse treatment planning system (Varian Medical Systems) was used for dose calculation. For the ISC, a fluence editor application was used to extend the range of optimal fluence. The treatment plan with the ISC was compared with the conventional technique in terms of doses in the planning target volume (PTV), dose homogeneity index (DHI), three-dimensional (3D) maximum dose, eye and lens doses and monitor unit (MU) counts required for treatment.
Compared with conventional WBRT, the ISC significantly reduced the DHI, 3D maximum dose and volumes receiving 105% of the prescription dose, in addition to reducing both eye and lens doses (p<0·05 for all comparisons). In contrast, MU counts were higher for the ISC technique than for conventional WBRT (828 versus 328, p<0·01).
The ISC technique for WBRT considerably improved the dose homogeneity in the PTV. As patients who receive WBRT have improved survival, the long-term side effects of radiotherapy are highly important.
The Kyoto 3-D Spectrograph was commissioned successfully at the 188-cm telescope of the Okayama Astrophysical Observatory in the spring of 1996. This instrument has four distinct modes (Ohtani et al. 1994): (1) narrow-band imager, which is an ordinary focal-reducer camera; (2) Spectro-NebulaGraph (long-slit spectrograph; Kosugi et al. 1995); (3) imaging Fabry-Perot interferometer, using either of two Fabry-Perot etalons from Queensgate Instruments (a tunable filter with R = 300 and another with R = 7000 for velocity-field observations. Broad-band (400–700 nm) coatings are deposited on both etalons. During observations, the etalon temperature is stabilized within 0.5°C); and (4) integral-field spectrograph of the TIGER-type (Bacon et al. 1995). In this mode, the spectra of 7 × 11 objects can be recorded simultaneously, along with 7 × 2 spectra of the sky 4′ away. The spatial resolution is 1″.3 and the field of view is 9″ × 14″.
Depth profiles of thermal donors introduced by heat treatment at 450°C in Czochralski-grown n-type silicon have been studied through capacitance-voltage measurements of Au Schottky diodes in the oxygen concentration range 8.1×1017 to 15.3×1017 cm3 Thermal donor concentrations increase with depth and their depth profiles are fitted to the error function equation. The obtained diffusivity decreases with annealing time and is higher for samples with the lower initial oxygen concentrations. Combining with the infrared absorption measurements, it is found that the curves of the diffusivity as a function of loss of interstitial oxygen coincide with each other. The similar tendency is observed on the oxygen diffusivity evaluated with secondary ion mass spectrometry. These results indicate that the oxygen diffusivity at 450°C is related to both the outdiffusion and clustering of oxygen. Depth profiles of thermal donors formed at 650°C are also reported.
Using the Subaru telescope and its FOCAS spectrograph in multi-object mode, we have obtained spectra of a selection of bright PNs in two galaxies: the Virgo giant elliptical M 60 (NGC 4649), and the starburst spiral M 82. We report on individual extinctions, as determined from the Balmer decrement, and also on the intensities of [O III] 4959 and 5007 relative to Hβ.
Newly designed abrasives with various particle morphology and component have been prepared and evaluated in terms of polish efficiency for CMP application. Polymer sphere with uniformed particle size and special functional group were prepared by soap-free emulsion polymerization. CMP slurry including polymer abrasives indicated characteristic properties such as dishing, erosion and low defectivity for metal and dielectric surface. This study has been also conducted on the preparation of composite particles consisting of polymer core covered with inorganic composition such as zirconium compound, titanium compound, SiO2 and Al2O3. The controlled hydrolysis and heterocoagulation systems were proposed as preparation methods of composite particles. 1st step Cu-CMP Slurry with composite particles as abrasion indicated an excellent dishing, erosion and their over-polish-margin. Particularly these composite particles were useful to prevent increasing scratch on the TEOS and low-k dielectric materials surface in 2nd step CMP process.
CMP slurry with inorganic/resin abrasive was investigated for the Al/low k damascene wiring.  The slurry showed less scratching, higher polishing rate and better planarity. These advantages are attributable to the elasticity of the resin. The soft resin particle behaves as a cushion and prevents the scratching caused by agglomerated inorganic particles and foreign material. The springy feature of the resin particle increases the selectivity of removal rate at convex portions and concave portions. Furthermore, the pressure is loaded to the Al film surface effectively through the resin particle and higher CMP rate can be achieved even without chemicals such as oxidizers and acids.  This chemical free polishing would be the advantageous for preventing the corrosion of Al.
The processes of phase transformation in individual nanoparticles of FePt and FePtCu synthesized by the reverse micelle method, which are chemically homogeneous and monodisperse, have been investigated by an in-situ HREM observation in a FE-TEM. Polycrystalline FePt particles, initially of chemically disordered face-centered cubic phase (A1) were reconstructed into A1 single crystals between 25 °C and 650 °C, followed by phase transformation from A1 to chemically ordered face-centered tetragonal phase (L10) which began between 650 °C and 680 °C. The coalescence began concurrently with phase transformation, i. e., between 650 °C and 680 °C. They turned to be a round-shaped L10 particle between 680 °C and 720 °C. The single crystal formation, the phase transformation from A1 to L10, the coalescence and the round-shaped particle formation were also observed in the FePtCu nanoparticles. The temperatures of single crystal formation, phase transformation (and coalescence) and round-shaped particle formation of the FePtCu nanoparticles were between 25 °C and 500 °C, between 550 °C and 600 °C and between 600 °C and 650 °C, respectively. These temperatures were substantially lower than those for the FePt nanoparticles.
The activation of phosphorus implanted into n-type silicon (100) substrate by followed hydrogen ion(H +) implantation was studied by means of spreading resistance technique(SR), secondary ion mass spectroscopy(SIMS) and transmission electron microscopy(TEM).
“The activation ratio” defined by carrier concentration divided by phosphorus concentration was used as a measure of activation of phosphorus. The H + energy, dose and dose rate dependence of activation ratio of phosphorus was investigated.
In the case of thermal annealing at 400 °C for 200 minutes the phosphorus atoms were not activated, on the other hand in the case of H + implantation at 400 °C the phosphorus atoms were activated and the activation ratio was increased almost proportionally with the dose. The SIMS data suggested that the depth profile of phosphorus atoms was not changed after activation by H + implantation. The activation ratio was increased with decreasing the dose rate. The TEM data suggested that the density of residual defects was reduced in the case of lower dose rate. The depth profile of activation ratio was similar to that of hydrogen atoms implanted at 20 °C. From these results the activation and recrystalization mechanism is discussed in the view of contribution of elastic collision process between H + ions and substrate atoms.
The degradation mechanism of the Schottky contact of Al/Ti/n-GaAs and Al/Pt/Ti/n-GaAs under the heat treatment of 300°C has been investigated. Barrier height of the Al/Ti/n-GaAs Schottky contact degrades drastically after the heat treatment, in which Ti-Al alloy and Ga out-diffusion have been observed. On the other hand, the barrier height of Al/Pt/Ti/n-GaAs contacts is stable under the heat treatment and, Al-Ti alloying as well as Ga out-diffusion in the metals could not be noticed. From these results, it is presumably concluded that the degradation of the Schottky contacts under the heat treatment is closely correlated with the Ga atom out-diffusion from GaAs surface into the metal films after Al-Ti alloy reach to the GaAs surface. The barrier height reduction after the heat treatment can be explained by the formation of the donor type level at the interface due to the Ga vacancy pile-up arose from the Ga out-diffusion. Pt layer was proved to be an effective barrier suppressing the intermetallic alloying and preventing out-diffusion of Ga.
Photocurrent multiplication has been observed in a-Si based p−i/SiNx/i−n junction cells under reverse biased high electric field. An apparent external quantum efficiency exceeds 20. A systematic investigation on electric and optoelectronic properties has been made to clarify the mechanism of photocarrier multiplication. The results indicate the possibility of inter-band tunneling via localized states in the a-SiN layer, which is induced by field-redistribution due to the built-up of trapped charges at the a-SiN/a-Si interface.
Electron traps in Czochralski–grown n-type (100) silicon with and without donor annihilation annealing have been studied by deep–level transient spectroscopy. A total of eight electron traps are observed in the concentration range 1010 –1011 cm −3. It is thought that these are grown–in defects during crystal growth cooling period including donor annihilation annealing. It is suggested that two electron traps labelled A2 (Ec–0.34 eV) and A3 (Ec–0.38 eV) of these traps are correlated with oxygen–related defects. It is shown that traps A2 and A3 are formed around 400 ° C and disappear around 500–600 ° C.
We investigated the initial oxidation of MBE-grown Si (100) surfaces with atomic flatness using x-ray photoemission spectroscopy (XPS) and reflection high energy electron diffraction (RHEED). It was found that the MBE-grown surfaces are inert and hardly oxidized even after exposure to molecular oxygen up to 1500 Langmuir (L) at room temperature. At elevated temperatures, the surface oxidation was substantially promoted. On the contrary, the surface oxidation was found to be substantiated on a deliberately corrugated Si surface prepared by low temperature MBE growth, even at room temperature.
The initial stages of SiO2/Si interface formation on hydrogen-terminated n-type and p-type Si(111) surfaces, which are obtained by the treatment in 40% NH4F solution, were investigated in details at 300°C in dry oxygen with a pressure of 1 Torr up to nearly two molecular layers of silicon oxide. It was found that the oxidation proceeds more uniformly on p-type Si than on n-type Si. However, even on p-type Si the oxidation does not proceed uniformly.
A series of experimental investigations has been made on the a-Si // poly-Si tandem solar cell which is one of the most promised candidate of high cost-performance photovoltaic cell, e.g., high efficiency, low cost with almost no light induced degradation. Employing high conductivity with wide optical band gap p type microcrystalline SiC (μ-SiC) as a window material together with a-SiC as an interface buffer layer and also n type μc-Si as a back ohmic contact layer in the poly-Si based bottom cell, the conversion efficiency of 17.2 % has been obtained. Combining an optically transparent a-Si p-i-n cell as a top cell with an optical coupler between the top and the poly-Si bottom cell, a total efficiency of 20.3 % has been obtained so far on the four-terminal stacked mode structure. A systematic technical data for the optimization of cell structure variation on the developed tandem solar cells are presented and further possibility to improving the performance are discussed.
We report on the free carrier Mobilities Measured by polarized electroabsorption Method. The result shows that the electron mobility reaches about 11.2cm2/Vs for device quality undoped a-Si:H, while the hole mobility is about 20% of the electron Mobility. Alloying with carbon leads to a continuous reduction of Mobility, with the largest drop (15%) for a carbon concentration of about 10 at.%, this being in sharp contrast to a less-pronounced effect by germanium alloying.