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An array of patch-antennas with meandering-gaps on an optical modulator is proposed for wireless millimeter-wave beam-steering through high-speed radio-over-fiber systems. Wireless millimeter-wave can be received by the array of patch-antennas and directly modulated to lightwave by the optical modulator. The wireless millimeter-wave can be steered using the meandering-gaps at the patch-antennas by controlling interaction between millimeter-wave and lightwave electric fields in electro-optic modulation. The basic operation and analysis of the proposed device are discussed. In the experiment, 5 × 5 antenna array in 40 GHz millimeter-wave bands was designed and realized for device characterization and demonstration to wireless millimeter-wave beam-steering. There were five variations of wireless millimeter-wave beam-steering for one-dimensional in xz- or yz-planes that can be obtained with wireless millimeter-wave steerable beams of about ±30°. Additionally, 25 variations of wireless beam-steering can be obtained for two dimension in xyz-space through orthogonal optical modulation. The proposed device is promising to be applied in millimeter-wave/tera-hertz bands for future directional wireless communication and sensing with high-speed and high-resolution operation.
We present an improved AC (Alternating Current) method for the determination of the Thomson coefficient, which can be used for obtaining the absolute Seebeck coefficient. While previous work has focused on DC (Direct Current) methods, we analyze the influence of an AC current in order to derive the Thomson coefficient of a thin wire from measurable quantities. Our expression requires five parameters including AC current, resistance, temperature gradient, and the temperature changes due to the Thomson and Joule effects. Thus, a prior determination of thermal conductivity and sample geometry is not required, unlike DC methods. In order to validate our analysis, the Thomson coefficient of a thin Pt wire has been measured at several frequencies. The results agree with those obtained from a conventional DC method.
Many sacoglossan sea slugs utilize chloroplasts ingested from food algae for photosynthesis (functional kleptoplasty), and the extent and duration of kleptoplast retention differs greatly among sacoglossan species. Although most recent studies focus on the genetic, microscopic, or physiological mechanisms responsible for this unique phenomenon, its effects on the life history traits of sacoglossans have not been fully explored. To study the effects of light conditions on survival and weight retention, adult individuals of two sacoglossan species, Elysia trisinuata and Plakobranchus ocellatus (‘black type'), were reared under light conditions (a 14-hour light: 10-hour dark photoperiod with an irradiance level of 28 µmol m−2s−1) or complete darkness for 21 days. There was no significant difference in the survival rate between the light and dark treatments for E. trisinuata, and its wet weight relative to the initial weight was smaller in the light than in the dark. However, both the survival and relative weights were greater in the light than dark for P. ocellatus. Based on the fluorescent yield measurement using pulse-amplitude-modulated fluorometry, the retention duration of functional chloroplasts was longer (>17 days) for P. ocellatus than E. trisinuata (<4 days). These results indicate that P. ocellatus benefits from photosynthesis for survival and growth, whereas E. trisinuata does not under starved conditions. This interspecific difference is likely related to the period of functional chloroplast retention.
Titanium oxide thin films were deposited at 250 – 400 °C on amorphous SiO2 prepared on n-type Si substrates by chemical vapor deposition (CVD) using a novel precursor, ethene-1,2-diylbis(tert-butylaminido)diisopropoxotitanium [Ti[N(tBu)C=CN(tBu)](OiPr)2 , Ti-DOT], with oxygen gas as an oxidant. Deposition characteristics of thin films were compared with those using titanium tetraisopropoxide [Ti(OiPr)4, TTIP]. As a result, the deposition amount of TiO2 thin films using Ti-DOT was larger than that of TTIP because of the shorter incubation time in the case of Ti-DOT. Smaller surface roughness was observed for the films using Ti-DOT. In addition, a good conformability was obtained on amorphous SiO2 hole prepared on n-type Si substrate substrate with aspect ratio of 5.
Crevice-corrosion tests were performed in gamma-ray irradiated high-temperature water of 288 °C on Type 316L stainless steel. The gamma-ray dose rate was about 30 kGy h−1. Tested specimen surfaces were analyzed using SEM, laser Raman spectroscopy and TEM/EDX. Experimental data were presented in order to show the differences made by the irradiation and crevice-shape simulated structure. Both gamma-ray irradiation and crevice-shape simulated structure changed the corrosion phenomena. On the gamma-ray irradiated crevice-shape simulated surface, α-Fe2O3 particles more than 5 μm in diameter were observed. It suggested that corrosion environment on the crevice-shape simulated surface became severer by gamma-ray irradiation.
We have studied the temperature dependence of thermoelectric properties of amorphous InN thin films prepared by reactive radio-frequency sputtering. We fabricated 60-pair and 120-pair InN-chromel films, which were deposited on polyimide films. For the 120-pair device, the maximum open output voltage and the maximum output power were 210 mV and 65 nW, respectively, at temperature difference of 168 K.
Nanostructured and thick SiC coatings have been successfully deposited on Si and graphite substrates by thermal plasma physical vapor deposition (TPPVD) using ultrafine SiC powder as a starting material. The control of processing parameters such as substrate temperature, composition of plasma gases, permits to the deposition of SiC coatings with a variety of microstructures and with various morphologies from dense to columnar. The maximum deposition rate reached 200 nm/s. Seebeck coefficient up to −480 μV/K was obtained for the non-doped coatings with stoichiometric composition. Nitrogen doping to the coatings made it possible to decrease the electrical resistivity from 10-2∼10-3 to 10-4∼10-5 Ωm and showing the maximum power factor of 1.0×10-3 Wm-1K-2 at 973 K.
In this paper we describe a new attempt of high-throughput screening of thermoelectric materials by combining the use of the “bulk composition-spread (CS)” or “bulk diffusion multiples (DM)” and the “scanning thermal probe microanalyzer (STPM).” The (Bi2Te3)1-x(Sb2Te3)x (0<x<1) and Ni1-xCux (0<x<1) bulk CS samples were prepared by conventional powder metallurgy method by using mechanical alloying and spark plasma sintering process. The Ni-Cu-X (X=Sn, In, Bi.) DM sample was prepared by post-heating of the CS samples in a molten metal. The two dimensional distributions of Seebeck coefficient and the thermal conductivity of the cross section of the CS and DM samples which composed of graded composition were visualized by using STPM at room temperature. The composition variation was checked by EDX. The relationship between composition and the thermoelectric properties was successfully determined by using the mapping results. The time required for mapping out the 100x100 pixel image was 8 to 11 hours. The total time required for this set of the screening experiment, from sample preparation to the final conclusion, was within 24 hours. For samples Ni-Cu-X DM the diffusion length of the elements at the interface can be large as 1mm and it was found that STPM is applicable to visualize the thermoelectric properties at the region of interest.
The thermoelectric properties of Ni1-xCux (0<x<1) alloy are measured from 323K to 950K. The sample with optimized composition, Ni70Cu30 is found to possess large power factor value of 0.012 Wm−1K−2 at around 950K. Estimated figure of merit value ZT is 0.21 for Ni50Cu50 and 0.18 for Ni70Cu30 at the same temperature. A novel attempt of high-throughput parallel synthesis using multiple-wells is carried out to test the feasibility of combinatorial approach in this material system. The Seebeck coefficient is visualized over the multiple-wells combinatorial library and the other Ni-Cu composition-spread, and it is proved that further enhancement of throughput could be possible by conducting systematic experiments based on the combinatorial approaches performed in this study.
In this paper, we demonstrate the use of thermal probe method that is capable of mapping Seebeck coefficient, thermal conductivity and contact resistance on a micrometer scale. We show the successful screening example on pseudo binary (Bi1−xSbx)2Te3 (0.5<x<1) bulk composition-spread sample prepared by conventional powder metallurgy process. Another demonstration is a novel attempt to combine the combinatorial PLD and the thermal probe method. A pseudo ternary diagram of nickel-copper-manganese oxides fabricated on Nb doped STO substrate was used for the screening. The mapping of electrical resistance over the ternary diagram yields a lot of information, which is essential for materials researches on complex, multi-composition systems.
The thermal oxidation kinetics of Si(110) surface up to oxide layer thickness of 1 ML has been investigated by real-time monitoring of chemical shifted in the Si 2p core-level photoemission using synchrotron radiation. The uptake profiles of every Si oxidation states (Sin+: n = 1 − 4) indicate that the top surface Si(110) oxidation proceeds through a two-step oxidation pathway via Si2+ state, just like the Si(001) surface. In contrast to the Si(001) oxidation, however, Si3+ state is always more abundant than Si4+ state during oxidation. This is related to occurrence of imperfect oxidation of this surface, most probably due to accumulation of compressive strain during oxidation.
The initial oxidation of Si(110)-16×2 clean surface has been investigated by using real-time synchrotron-radiation photoemission spectroscopy and scanning tunneling microscopy. The Si(110) initial oxidation is characterized by its unique rapid oxidation right after the introduction of oxygen molecules, which is most likely attributed to the preferential reactions at the pentagon pairs of the 16×2 reconstruction.
Bi2Te3-based thin films were fabricated on glass substrates by the pulsed laser deposition (PLD) method. The vapor pressures of Bi and Te are significantly different, so controlling the stoichiometric composition is difficult when using conventional physical vapor deposition techniques, and the thermoelectric properties of Bi2Te3 films are sensitive to the film composition. PLD is a promising technique for the fabrication of telluride-based films such as Bi2Te3 due to its superior capability for controlling the film composition. Another advantage of PLD is the flexibility that it allows in terms of atmosphere in the reaction chamber; high concentrations of gases such as oxygen or argon can be introduced. We have measured various compositions of Bi2Te3 based films, and have identified the optimal compositions for both n-type and p-type material. The thermal conductivities of these Bi2Te3 films were evaluated by an exact measuring system, and the results were twice as low as those of conventional bulk materials. These results suggest that PLD has significant advantages for the deposition of in-plane Bi2Te3-based thin films.
We propose multi-layer near-field recording with using inner focus mode. The restricted conditions for multi-layer near-field recording are discussed from the viewpoint of both media structure and optical setup. One solution is presented for dual layer recording with a numerical aperture (NA) of 1.5 and a wavelength of 405 nm as a light source of GaN laser diode.
In the proposed layer structure, a Nb2O5 material has been adopted as the intermediate layer because of its high refractive index, n = 2.4, in order to prevent the decrease of beam propagation that corresponds to NA>1. Almost the same signal characteristics can be obtained from both recording layers at the air gap of 40 nm. The adjustment of focusing position and the compensation of spherical aberrations have been implemented by the combination of an expander lens unit and a liquid crystal (LC) panel in the optical setup.
High-energy protons are generated by focusing an ultrashort pulsed
high intensity laser at the Advanced Photon Research Center, JAERI-Kansai
onto thin (thickness <10 μm) Tantalum targets. The laser
intensities are about 4 × 1018 W/cm2. The
prepulse level of the laser pulse is measured with combination of a PIN
photo diode and a cross correlator and is less than 10−6.
A quarter-wave plate is installed into the laser beam line to create
circularly polarized pulses. Collimated high energy protons are observed
with CH coated Tantalum targets irradiated with the circularly polarized
laser pulses. The beam divergence of the generated proton beam is measured
with a CR-39 track detector and is about 6 mrad.
Past history of mass casualties related to international football games brought the importance of practical planning, preparedness, simulation training, and analysis of potential patient presentations to the forefront of emergency research.
The Japanese Ministry of Health, Labor, and Welfare established the Health Research Team (HRT-MHLW) for the 2002 FIFA World Cup game (FIFAWC). The HRT-MHLW collected patient data related to the games and analyzed the related factors regarding patient presentations.
A total of 1,661 patients presented for evaluation and care from all 32 games in Japan. The patient presentation rate per 1,000 spectators per game was 1.21 and the transport-to-hospital rate was 0.05. The step-wise regression analysis identified that the patient presentations rate increased where access was difficult. As the number of total spectators increased, the patient presentation rate decreased. (p <0.0001, r = 0.823, r2 = 0.677).
In order to develop mass-gathering medical-care plans in accordance with the types and sizes of mass gatherings, it is necessary to collect data and examine risk factors for patient presentations for a variety of events.
We systematically studied the temperature and time dependence of phase formation of HgBa2Can−1CunO2(n+1)+δ [Hg-12(n − 1)n, n = 1, 2, 3, 4] superconductors by a single step firing method. All samples were synthesized from high-purity HgO, BaO, CaO, and CuO in a sealed quartz tube. The phase formation of Hg-12(n − 1)n was examined by both x-ray diffraction (XRD) analysis and dc susceptibility measurement. A single-phase HgBa2CuO4+δ (Hg-1201) was obtained in a relatively wide temperature range (600–850 °C), while single-phase HgBa2CaCu2O6+8 (Hg-1212) and HgBa2Ca2Cu3O8+δ (Hg-1223) were obtained only in narrow temperature and time ranges for the synthesis. The optimum temperatures for Hg-1212 and Hg-1223 were found to be 665 and 710 °C, respectively, when the sintering time was fixed for about 50 h. The HgBa2Ca3Cu4O10+δ (Hg-1234) phase was obtained as a mixture with Hg-1223.
We report a case of recurrent laryngeal papillomatosis which developed into laryngeal squamous cell carcinoma 11 years after the first diagnosis. Interestingly, we could identify HPV type 18 DNA in the carcinoma tissue using the polymerase chain reaction (PCR). Other known risk factors of irradiation, smoking, exposure to chemical agents, or a hereditary tendency to malignant tumours were not present in this case. Our finding suggests that HPV type 18 is another aetiological agent for laryngeal carcinoma.
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