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We present recent observation results of Sgr A* at millimeter obtained with VLBI arrays in Korea and Japan.
7 mm monitoring of Sgr A* is part of our AGN large project. The results at 7 epochs during 2013-2014, including high resolution maps, flux density and two-dimensional size measurements are presented. The source shows no significant variation in flux and structure related to the G2 encounter in 2014. According to recent MHD simulations by kawashima et al., flux and magnetic field energy can be expected to increase several years after the encounter; We will keep our monitoring in order to test this prediction.
Astrometric observations of Sgr A* were performed in 2015 at 7 and 3.5 millimeter simultaneously. Source-frequency phase referencing was applied and a combined ”core-shift” of Sgr A* and a nearby calibrator was measured. Future observations and analysis are necessary to determine the core-shift in each source.
The nearby radio galaxy M87 offers a unique opportunity for exploring the connection between γ-ray production and jet formation at an unprecedented linear resolution. However, the origin and location of the γ-rays in this source is still elusive. Based on previous radio/TeV correlation events, the unresolved jet base (radio core) and the peculiar knot HST-1 at >120 pc from the nucleus are proposed as candidate site(s) of γ-ray production. Here we report our intensive, high-resolution radio monitoring observations of the M87 jet with the VLBI Exploration of Radio Astrometry (VERA) and the European VLBI Network (EVN) from February 2011 to October 2012. During this period, an elevated level of the M87 flux is reported at TeV with VERITAS. We detected a remarkable flux increase in the radio core with VERA at 22/43 GHz coincident with the VHE activity. Meanwhile, HST-1 remained quiescent in terms of its flux density and structure at radio. These results strongly suggest that the TeV γ-ray activity in 2012 originates in the jet base within 0.03 pc (projected) from the central supermassive black hole.
We present VLBI maps of the 6.7 GHz methanol maser emission in 32 sources obtained using the Japanese VLBI Network (JVN) and the East-Asian VLBI Network (EAVN). All of the observed sources provide new VLBI maps, and the spatial morphologies have been classified into five categories similar to the results obtained from European VLBI Network observations (Bartkiewicz et al. 2009). The 32 methanol sources are being monitored to measure the relative proper motions of the methanol maser spots.
We present the internal proper motion of 6.7-GHz methanol masers in S269, an Ultra Compact HII region. The maser distribution in S269 consists of several maser groups, and the spatial structure of the main groups A and B are consistent with the past VLBI image. The remarkable result of comparing the two VLBI maps is that 6.7-GHz methanol maser distribution and velocity range within each group have been kept for eight years. Angular separation between the two groups A and B increases by 3.6 mas, which corresponds to a velocity of 11.5 km s−1.
We present VLBA observation towards the nucleus of a nearby radio galaxy NGC 1052. In NGC 1052, two-sided jet structure and a dense plasma circumnuclear torus with a radius of 0.7 pc have been found around the central mass. It emits a H2O megamaser, which is redshifted with respect to the systemic velocity of the galaxy (1491 kms−1) with a large velocity width of 100 kms−1 (FWHM). The maser gas is found at the inner jet components of both the approaching and receding jets. The maser gas is positionally coincident with a plasma torus. The maser gas in NGC 1052 could be explained as a circumnuclear torus or disk, as found for the nucleus of NGC 4258.
The impact of the conduction band offset (CBO) between window/Cu(In,Ga)Se2 (CIGS) layers on the light soaking (LS) effect in CIGS solar cells has been studied with continuous CBO control using a (Zn,Mg)O (ZMO) window layer. Two types of CIGS solar cells with different window/buffer/absorber layers configurations were fabricated, i.e., ZMO/CIGS (without buffer layer) and ZMO/CdS/CIGS structures. The CBO values between ZMO and CIGS layers were controlled to -0.15~0.25 eV. Plus and minus signs of CBO indicate the conduction band minimums of ZMO above and below that of CIGS, respectively. Current-voltage (J-V) characteristics of the solar cells with different LS durations revealed that a positive CBO value higher than 0.16 eV induces J-V curve distortion, i.e., LS effect, and all the J-V characteristics stabilized in 30 min. The degrees of the LS effect were dominated by the CBO value between ZMO and CIGS layers in the both structure regardless of the existence of CdS buffer layers. These results indicate that the LS effect is dominated by the highest barrier for photo-generated electrons in the conduction band diagram, i.e., the CBO between ZMO and CIGS layers, and quantitatively the LS effect emerges the CBO value higher than 0.16 eV.
The sheet resistance and sheet carrier concentration for Si ion implanted GaN have been investigated as a function of Si ion dosages and ion's energy using van der Pauw method and Hall effect measurement. Si ion implanted GaN is annealed at 1200 °C for 10 sec in N2 gas flow with 50 nm-thick SiNx cap layer to avoid dissociation of GaN. For Si ion energy of 30 keV, the sheet resistance is decreased from 103 to 56 ohm/sq. for the dose ranging from 1 × 1014 to 2 × 1015/cm2. For the Si dose larger than 2 × 1015/cm2, the sheet carrier concentration is saturated around 1 ×s 1015/cm2. Si ion implanted GaN with energy of 50, 80, and 120 keV at a dose of 2 × 1015/cm2 also reveal the sheet carrier concentration of about 1 × 1015/cm2 with the decrease of electron mobility. It is suggested that the implanted Si donors are strongly compensated by the residual implantation-induced defects.
Background and objectives: Sodium bicarbonate is the most physiological alkalinizing agent. The effect of a new bicarbonated Ringer's solution (BRS) containing Mg2+, on metabolic acidosis and serum magnesium abnormality were evaluated and compared with those of acetated Ringer's (ARS), lactated Ringer's (LRS) and Ringer's (RS) solutions in an experimental haemorrhagic shock model with dogs. Methods: Animals were randomly divided into six groups (n = 6 in each group), a sham-operated group, an operated group without infusion, and 4 operated groups with infusion (BRS, ARS, LRS and RS groups). Each RS was intravenously administered at 60 mL kg−1 h−1 for 1.5 h. Arterial blood gases, plasma electrolytes and cardiovascular parameters were analysed. Results: BRS significantly improved blood base excess values, which were decreased by blood-letting, faster and more markedly than did LRS and RS (BRS −6.3 ± 0.5 mEq L−1; LRS −9.2 ± 1.1 mEq L−1; RS −12.4 ± 1.0 mEq L−1 at the end of infusion). The alkalinizing effect of BRS tended to be better than that of ARS but not significantly so. The serum Mg2+ concentration was well-maintained by BRS as compared to other RS (BRS 1.5 ± 0.0 mg dL−1; ARS 1.2 ± 0.0 mg dL−1; LRS 1.1 ± 0.0 mg dL−1; RS 1.3 ± 0.1 mg dL−1, at the end of infusion). Conclusions: These results suggest that BRS is a suitable perioperative solution for metabolic acidosis and serum electrolyte balance among RS tested.
Background and objective: The effects of bicarbonated Ringer's solution were evaluated and compared with those of acetated Ringer's, lactated Ringer's and Ringer's solutions in partially hepatectomized rabbits. Method: Animals were randomly divided into six groups (n = 6 in each group): a sham-operated group, an operated group without infusion, and four operated groups with infusions of each of the four Ringer's solutions. Each Ringer's solution was intravenously administered at 40 mL kg−1 h−1 for 1.5 h. Arterial blood gases, plasma magnesium concentrations and cardiovascular parameters were analysed. Results: The partial hepatectomy-induced decrement of base excess was inhibited by bicarbonated Ringer's solution more remarkably than by either lactated or plain solutions (P < 0.01). The alkalinizing effect of bicarbonated Ringer's solution tended to be more marked than that of the acetated solution but not significantly so. Plasma magnesium concentrations were well maintained by bicarbonated solution as compared to the other solutions (P < 0.01). Conclusions: These results suggest that bicarbonated Ringer's solution is the most suitable perioperative solution for metabolic acidosis and plasma electrolyte balance among the Ringer's solutions tested.
Amphibole in the Larvik alkaline plutonic complex in the Oslo rift, Norway, has Ti-rich compositions from edenite through pargasite to kaersutite, and has a large H+ deficiency (0.7–1.1 atoms per formula unit: a.p.f.u.) with a large oxy component in the amphibole OH– site (O2– = 2 – (OH + F + Cl) = 0.2–0.9 a.p.f.u.), similar to the mantle-derived kaersutites. Their compositions reveal a characteristically low Fe3+/(Fe3++Fe2+) ratio (<0.23) and a high F concentration (0.3–0.9 a.p.f.u.). Correlation with the Fe3+ ratio caused by Fe2+ + OH– = Fe3+ + O2– + 1/2H2 substitution is negligible, which is supported by H and O isotope compositions. A possible substitution, Al3+ + OH– = Ti4+ + O2– may be operative for Larvik kaersutites when the O2–/Ti is 1.0. A relatively larger O2–/Ti ratio (1.2—2.0) suggests an another kaersutite substitution mechanism, R2+ + 2OH– = Ti4+ + 2O2–, where R2+ = Fe2+ + Mg + Mn. These effects might result in the limited O2–/Ti ratio value from 1.0 to 2.0.
A negative correlation between Ti and F, suggesting F incorporation into kaersutite may diminish the O2–/Ti ratio, not only due to the occupation of this non-oxy species in the O3 site, but also due to F—Ti avoidance. Composition-dependent H and O isotope variations (δD = –106 to –71% and δ18O = 4.6–5.2%) suggest equilibrium in the closed-system magma with differentiation. The mineral chemistry of Larvik oxy-kaersutitic amphibole could reflect the crystallization in a closed-system magma during rifting with passive crustal thinning at the Oslo palaeorift.
We fabricated a DC inorganic electroluminescent (EL) device whose structure is ITO electrode / ZnS:Mn / ZnO (Mn) nanorods / p−/p++-Si(111) / Au electrode. ZnO nanorods were grown by chemical vapor deposition method combined with laser ablation. ZnS:Mn and ITO were deposited by electron-beam-deposition. We studied on annealing effects of ZnO nanorods on the electrical and electroluminescent characteristics of this device. The device without annealing showed a low breakdown voltage, and any EL emission could not be observed. On the other hand, the device with annealing showed higher impedance and higher breakdown voltage, and the EL emission from the ZnS:Mn layer was observed. An intense EL emission was observed from a peripheral of ITO electrode. An EL emission from the inside area of ITO electrode was very weak.
Co-doped ZnS:(Mn, Si) films were fabricated. The ZnS was synthesized by a low-pressure thermal chemical vapor deposition. Metal Zn vapor and H2S gas were used as the CVD-precursors. Mn and Si were doped using a laser ablation technique during the ZnS growth. A solid MnSi alloy (Mn:Si = 1:1) was used as the laser ablation target. The films were deposited at the range from 650°C to 750°C. At the deposition temperature of 650°C, only a EL emission peak at 585 nm same as conventional ZnS:Mn films appeared, i.e., the Si co-doping had no effects on the EL spectrum. At the deposition temperature of 700°C, the Si co-doping to ZnS:Mn film caused the shift of the EL emission peak at 585 nm to shorter wavelength by 15 nm and provided new EL emission at 760 nm. The film deposited at 750°C exhibited new UV and blue EL emissions at 390 nm and 450 nm, respectively, although the host material of the film differed from usual ZnS.
We investigated the effect of a small dose of midazolam, ketamine, droperidol or lidocaine on the propofol dose required for hypnosis during induction of general anaesthesia. These drugs were randomly administered to 100 patients about to undergo scheduled surgery. Propofol was then infused at a rate of 250 μg kg−1 min−1 and the hypnotic dose to produce hypnosis was evaluated. Midazolam (20 μg kg−1) and droperidol (20 μg kg−1) significantly reduced the mean hypnotic dose of propofol (mean) S.D.) compared with the placebo (43.7 ± 17.8 mg, 61.9 ± 10.6 mg and 72.5 ± 27.7 mg after pretreatment with midazolam, droperidol and placebo, respectively), whereas ketamine (0.1 mg kg−1) and lidocaine (1 mg kg−1) did not significantly affect the hypnotic dose of propofol (63.1 ± 25.6 mg and 65.1 ± 24.8 mg, respectively). Only midazolam when compared with saline administration, (176 ± 66s and 298 ± 126s, respectively), shortened the time to achieve hypnosis. The changes in blood pressure (non-invasive) and heart rate were not significantly different in all groups during the induction of anaesthesia and oro-tracheal intubation. These results raise the possibility that new combinations of central nervous system drugs, such as droperidol and propofol, have a potential to reduce the dose of intravenous anaesthetics, including propofol, that produce hypnosis without significant adverse effects.
Much attempts of statistical approach have been made to study the origin of heavy elements, distribution of dark matter and evolution of clusters of galaxies. Henry et al.(1991) reported a power-law relation; LX ∝ kTγ, γ ~ 2.7. Edge and Stwert(1991) found significant scatter in the correlation using 45 clusters. David at al.(1993) reported γ ~ 3.4 using 104 clusters.
We present multi-frequency observations towards the nucleus of NGC 3079 using both Japan VLBI Network (J-Net) and the VLBA including phased VLA and Effelsberg. We detected two continuum components at 1.4 and 8.4 GHz, and determined the spectral indices for each component. Further, we found several H ɪ absorption features towards the continuum components whose velocity gradient is opposite to the galaxy rotation. Assuming rotation, the central mass is estimated to be 3 × 106M⊙. The water maser distribution extends in North-South direction along the galactic disk, while no clear indication of a Keplerian rotating disk was found.
To study immunological responses in filarial infections, interleukin-2
receptor α (IL-2Rα) expression in the peripheral blood lymphocytes
(PBL) of Lewis rats infected with Brugia pahangi was observed
by flow cytometry. During infection, no increase in IL-2Rα was observed
in either microfilaraemic or amicrofilaraemic rats. The PBL of rats were
stimulated with phytohaemagglutinin (PHA) and the frequency of IL-2Rα-positivity
was examined. After microfilariae appeared, the increase in the rate of
IL-2Rα-positivity in microfilaraemic rats was less than in amicrofilaraemic
rats. The anergy of IL-2Rα expression in microfilaraemic rats was
restored when their lymphocytes were cultured with normal rat serum. IL-2Rα
expression in normal uninfected rats decreased when cultured with serum
from microfilaraemic rats. These results suggest that microfilariae-related
factors in rat serum suppress PHA-induced IL-2Rα expression in PBL
and thus inhibit cell proliferation and host immunity.
We have succeeded in preparing a conductive polyaniline (PAn) with improved thermal stability from a chemical oxidative polymerization of aniline by using an oxidant and a novel protonic acid, m-xylylenedisulfonic acid (XDSA). The acid was synthesized from dibromoxylene and characterized by elemental analysis, IR and NMR spectroscopies. The polymer which is doped with XDSA shows a high conductivity of 5 S/cm. The conductivity does not change with annealing at 125°C in air for over 1000 hours. This polymer exhibits good thermal stability, and this stability is attributed to XDSA dopant, which consists of a bi-functional sulfonic group bonded to a polymer chain. By immersing an anodized tantalum pellet into a reactive solution, PAn doped with XDSA film is formed on the dielectric surface. The tantalum capacitor using PAn doped with XDSA as a counter electrode shows the improved characteristics: high apparent capacitance (90%), and small series resistance (<200mΩ at 100kHz). The capacitor demonstrates an excellent thermal stability due to because of the exceptional heat-resistance of PAn doped with XDSA formed in the capacitor.