Search

An on‐ground observation program for high‐energy atmospheric phenomena in winter thunderstorms along the Japan Sea has been performed via measurements of gamma ray radiation, atmospheric electric field, and low‐frequency radio band. On 11 February 2017, the radiation detectors recorded gamma ray emission lasting for 75 s, and then abruptly terminated with a nearby lightning discharge. The gamma ray spectrum extended up to 20 MeV and was reproduced by a cutoff power law model with a photon index of 1.36−0.04+0.03, being consistent with Bremsstrahlung radiation from a thundercloud (known as a gamma‐ray glow or a thunderstorm ground enhancement). The low‐frequency radio monitors, installed ∼50 km away from the gamma ray observation site recorded leader development of an intracloud/intercloud discharge spreading over ∼60 km area with a ∼300‐ms duration. The timing of the gamma ray termination coincided with the moment when the leader development of the intracloud/intercloud discharge passed 0.7 km horizontally away from the radiation monitors. The intracloud/intercloud discharge started ∼15 km away from the gamma ray observation site. Therefore, the glow was terminated by the leader development, while it did not trigger the lightning discharge in the present case. This study presents high‐energy radiation, atmospheric electric field and low‐frequency radio measurements of winter thunderstorms in Japan. Long‐duration gamma ray bursts, called “gamma ray glows,” are thought to originate from electrons accelerated and multiplied by strong electric fields in thunderclouds. There are unsolved questions such as electron‐acceleration mechanisms, position of the acceleration site, lifetime, and life cycle of the bursts. We observed a gamma ray burst lasting for ∼75 s from a thundercloud abruptly terminated with a lightning discharge. The gamma ray source was destroyed by a cloud‐to‐cloud discharge over the gamma ray observation site but not related to the triggering of the discharge in the present case. A gamma ray glow and its termination with a lightning discharge was observed in a Japanese winter thunderstormThe glow was terminated by leader development of a horizontally long intracloud/intercloud discharge passing nearby overheadThe intracloud/intercloud discharge was not triggered by the glow in the present case because it started far from the gamma ray glow site

AbstractLaser–plasma interaction and hot electrons have been characterized in detail in laser irradiation conditions relevant for direct-drive inertial confinement fusion. The experiment was carried out at the Gekko XII laser facility in multibeam planar target geometry at an intensity of approximately $3\times {10}^{15}$ W/cm2. Experimental data suggest that high-energy electrons, with temperatures of 20–50 keV and conversion efficiencies of $\eta <1\%$ , were mainly produced by the damping of electron plasma waves driven by two-plasmon decay (TPD). Stimulated Raman scattering (SRS) is observed in a near-threshold growth regime, producing a reflectivity of approximately $0.01\%$ , and is well described by an analytical model accounting for the convective growth in independent speckles. The experiment reveals that both TPD and SRS are collectively driven by multiple beams, resulting in a more vigorous growth than that driven by single-beam laser intensity.

Aims.Understand the shape and implications of the multiband ligth curve of GRB 050408, an X-ray rich (XRR) burst.

Context.The origin of X-ray Flashes (XRFs) is still a mystery and several models have been proposed. To disentangle among these models, an important observational tool is the measure of the XRF distance scale, so far available only for a few of them.

Context. As a result of the numerous missions dedicated to the detection of Gamma-ray bursts (GRBs), the observed properties of these events are now well known. However, studying their parameters in the source frame is not simple since it requires having measurements of both the bursts' parameters and of their distances.Aims. Taking advantage of the forthcoming Catalog of the High Energy Transient Explorer?2 (HETE-2) mission, the aim of this paper is to evaluate the main properties of HETE-2 GRBs?? the peak energy (Epeak), the duration?(T90) and the isotropic energy (Eiso) ? in their source frames and to derive their unbiased distribution.Methods. We first construct a complete sample containing all the bursts localized by the Wide-Field X-ray Monitor (WXM) on-board HETE-2, which are selected with a uniform criterion and whose observed parameters can be constrained. We then derive the intrinsic?Epeak, T90and Eiso? distributions using their redshift when it is available, or their pseudo-redshift otherwise. We finally compute the ?volume of detectability??Vmaxof each GRB, i.e. the volume of the universe in which the burst is bright enough to be part of our sample, and the corresponding number of GRB within their visibility volume?NVmax, in order to derive a weight for each detected burst accounting both for the detection significance and the star formation history of the universe.Results. We obtain unbiased distributions of three intrinsic properties of HETE-2 GRBs: Epeakintr, T90intrand the isotropic energy of the burst. These distributions clearly show the predominence of X-ray flashes (XRFs) in the global GRB?population. We also derive the rate of local GRBs: R0H2?? 11?Gpc-3?yr-1, which is intermediate between the local rate obtained by considering only the ?high-luminosity? bursts (~1?Gpc-3?yr-1) and that obtained by including the ?low-luminosity? bursts (?200?Gpc-3?yr-1).Conclusions. This study shows that the XRFs are predominent in the GRB population and are closely linked to the ?classical? GRBs. We show that HETE-2 detected no low-luminosity GRB like GRB?980425 or XRF?060218, due to the small size of its detectors, excluding this type of burst from our statistical analysis. The comparison of the GRB?rate derived in this study with the known rate of type?Ib/c supernovae clearly shows that the progenitors of SNe?Ib/c must have some special characteristics in order to produce a gamma-ray burst or an X-ray flash.

Abstract: The condensation experiments of zinc vapor on the solid media in Zn(g)-CO-CO2-Ar mixtures were conducted in a flow reactor at 800 C to 1000 C under a zinc partial pressure of 0.6 to 7.9 kPa. The condensates were weighed, and the zinc contents and their morphology were analyzed to investigate the effects of various factors on the condensation. It was found that the initial temperature of the media should be as low as possible in liquid condensation for the efficient recovery of zinc. The condensation is enhanced with zinc partial pressure of the gases. The medium made of silica with a smooth surface is favorable for the efficient condensation. In the gases not oxidizing to zinc vapor, metallic zinc can be obtained on the medium with an initial temperature over the range of 120 C to 400 C. For obtaining metallic zinc, it is necessary to raise the temperature of the gases, appropriately limit the zinc partial pressure, or maintain a sufficient CO/CO2 ratio to avoid the oxidation of zinc vapor.

A three-stage fluidizing-bed process consisting of chlorination, selective oxidation and sulfur chloride conversion was tested for processing chalcopyrite concentrate. It was found that the use of excess oxygen was essential for the stable operation of the oxidation reactor. The excess-oxygen gas inevitably causes the oxidation of the sulfide concentrate in the chlorination and sulfur chloride conversion reactors. A new flowsheet is proposed to separate the chlorination and selective oxidation steps with separate flow paths of the fluidizing gases, thereby, preventing the passage of excess-oxygen gas in the chlorination and sulfur chloride conversion reactors. The feasibility of the proposed flowsheet was demonstrated in a laboratory-scale fluidizing bed setup.

Abstract: In this work, we grew lead titanate (PbTiO3) and La-modified PbTiO3 thin films on platinized silicon (Si(100)) substrates under controlled substrate temperature and ambient by a modified jet-vapor deposition (JVD) process described in this paper. The x-ray diffraction patterns obtained from these films showed a single-phase perovskite structure. We examined locally homogeneity and thickness of these films through the comparative use of laser Raman spectroscopy. We also collected Raman and x-ray data on pure PbTiO3, as well as prepared lead zirconate titanate (PZT) (54/46), and PZT (50/50) films using the JVD process. This paper discusses the temperature variations of the pyroelectric and dielectric properties of three compositions of La-modified PbTiO3 films containing 5.2% to 15% of La, respectively, with a view toward studying the effect of La in place of Pb on these electrical properties. We detected significant pyroelectric currents on all three La-modified PbTiO3 films before performing poling treatments, and observed pyroelectric coefficeints as high as 84 nC/cm2·°C in the poled La-doped PbTiO3 films containing 5.2% La. The pyroelectric coefficient and dielectric constant varied significantly with La content. We compared the calculated figures of merit, which were based on the measured physical properties, with pure PbTiO3 as well as PZT and lead lanthanide zirconate titanate (PLZT) films. These properties just described illustrate that these films would be suitable for IR detectors.

A gaseous chlorination process for the hydrometallurgical treatment of a chalcopyrite concentrate was investigated. The overall process is visualized to consist of low-temperature chlorination-selective oxidation, followed by aqueous chloride leaching and SX-EW for producing electrolytic copper, elemental sulfur and ferric oxide. In this article, the chlorination phase of the process is described. Initially, the chlorination behavior of chalcopyrite concentrate micropellets was investigated using a small batch-type fluidized bed reactor. The optimum conditions thereby established were used in continuous chlorination tests. The chlorinated products thus prepared were used in the selective oxidation phase of the investigation.

A low-temperature-chlorination selective oxidation followed by aqueous chloride leaching and SX-EW for producing electrolytic copper, elemental sulfur and ferric oxide was investigated for hydrometallurgical processing of a chalcopyrite concentrate. In this article, the selective oxidation phase of the process is described. The selective oxidation requires a temperature well above the CuCl-FeCl3eutectic points. The test procedure was developed with a batch reactor and then tested with a continuous reactor. The process was initiated by adding small amounts of chlorinated samples to a fluidizing bed of dead-roasted sulfide concentrate micropellets. The selectively oxidized samples thus prepared were shown to fully dissolve copper, while virtually all the iron remained undissolved.

Experiments E866 and E917 at the AGS have measured the differential invariant yields of positive and negative charged kaons from Au+Au collisions at beam kinetic energies in the laboratory of 2, 4, 6, 8, and 10.8 A·GeV. At each beam energy, a multiplicity array is used to select on the centrality of the collision.

Not Available

Ferroelectric thin films have been integrated with silicon micromechanical structures in the fabrication of microsensor and microactuator structures. Both the piezoelectric and pyroelectric effects in thin films of lead zirconate titanate (Pb(ZrxTi1_x)O3) and lead titanate (PbTiO3) have been used for physical force sensing (pressure sensor), thermal heat sensing (pyroelectric infrared detector) and microactuation (mechanical positioner). Solid-state micromachining is used to form mechanical membranes on a silicon wafer for implementing easily deformable membranes or structures with a low thermal mass. This paper demonstrates the compatible simultaneous integration of 1) sol-gel deposited ferroelectric thin films, 2) surface-machined micromechanical structures and 3) n-well CMOS integrated circuit technologies.

We studied the effects of adrenoceptor antagonists and imidazoline derivatives on endogenous adrenaline-induced inhibition of insulin release in anesthetized rats. The intracerebroventricular injection of neostigmine increased plasma levels of catecholamines and glucose but not insulin. Pretreatment with an i.p. injection with phentolamine caused a dose-dependent increase in insulin secretion. When atropine was coadministered with phentolamine, the phentolamine-induced increase in insulin secretion was inhibited. Neither phentolamine nor atropine affected plasma levels of catecholamine. Yohimbine and idazoxan, which are @a"2-adrenoceptor antagonists, and tolazoline, a non-selective @a-adrenoceptor antagonist, also reversed adrenaline-induced inhibition of insulin secretion. Phenoxybenzamine, prazosin, propranolol, and antazoline, an imidazoline without @a"2-adrenoceptor activity, did not affect insulin levels. When agents were preinjected i.p. in rats that were given saline into the third cerebral ventricle, phentolamine and antazoline, but not yohimbine and idazoxan, increased plasma levels of insulin. The results suggest that the inhibition of insulin release induced by adrenaline was reversed by antagonism of @a"2-adrenoceptors. Phentolamine and antazoline, both of which are imidazoline derivatives, induced insulin secretion independently of the adrenoceptors only under the resting conditions.

Roles of Ca/calmodulin-dependent protein kinase II (Ca/CaM kinase II) and myosin light chain kinase (MLCK) in insulin release from rat pancreatic islets were investigated. Western blotting using polyclonal antibody to Ca/CaM kinase II suggested the presence of this kinase in the pancreatic islets. Extracts of pancreatic islets phosphorylated exogenous myosin light chain, which was inhibited by ML-9, an inhibitor of MLCK. KN-62 and KN-93, inhibitors of Ca/CaM kinase II, and ML-9 at μM concentrations inhibited insulin release stimulated by glucose or high K+. KN-62 and KN-93, but not ML-9, inhibited insulin release increased by glucose and forskolin, an activator of adenylate cyclase. These inhibitors had no effect on insulin release evoked by 12-O-tetradecanoyl phorbol-13-acetate, an activator of Ca2+-sensitive, diacylglycerol-dependent protein kinase. These results suggest that Ca/CaM kinase II and MLCK may participate in the control of insulin release.

Magnesium, the most abundant intracellular divalent cation, is an essential cofactor for many enzyme systems1, but it remains unknown as to whether variations in the cytoplasmic concentration of ionized Mg2+directly control cellular processes. Experiments with adrenal medullary cells made ‘leaky’ by exposure to high electric fields provided evidence that Mg2+could influence hormone release not only by competing with Ca2+for entry into the cell, but also at intracellular sites controlling exocytosis2,3. A similar conclusion was reached for insulin release in a study4using isolated rat islets also subjected to high voltage discharges. There is no experimental evidence, however, that physiological stimuli influence Mg2+movements in intact secretory cells. We report here that 28Mg2+fluxes in pancreatic islet cells are markedly modified by glucose, the physiological stimulus of insulin release, but not by its non-insulinotropic analogue, 3-O-methylglucose.

is performed using CF2Cl2/Ar gas mixtures.