It is argued that the cosmic X-ray background (CXB) is not dominated by sources that are usual active galaxies or quasars. A comparable number of objects, young galaxies at z < 4 containing massive black holes surrounded by hot optically thin accretion disks, constitute the precursor active galaxies (PAG) postulated here for producing the thermal type spectrum required for the CXB. An evolution...

In relativistic strongly magnetized winds outflowing from the fast-rotating compact progenitors of gamma-ray bursts (GRBs) there are three regions where powerful high-frequency emission may be generated: (i) the thermal photosphere, (ii) the region of the internal wind instability and (iii) the region of the wind interaction with an ambient gas. This results in a multicomponent structure of GRB...

Recent observations suggest that long-duration γ-ray bursts and their afterglows are produced by highly relativistic jets emitted in core-collapse explosions. As the jet makes its way out of the stellar mantle, a bow shock runs ahead and a strong thermal precursor is produced as the shock breaks out. Such erupting fireballs produce a very bright γ-ray precursor as they interact with the thermal...

The fabrication process of ceramic yttria-stabilized zirconia (YSZ) and nickel oxide nanofibers by electrospinning is reported. The preparation of hollow YSZ nanofibers and aligned nanofiber arrays is also demonstrated. The influence of the process parameters of the electrospinning process, the physicochemical properties of the spinning solutions, and the thermal treatment procedure on spinnabi...

The controlled synthesis of Mg(OH)(2) nanowires and microflowers composed of nanoplates was successfully achieved by a template-free hydrothermal synthetic method. It was found that the reaction medium played a crucial role in the morphological control of the precursor nanostructures. The high polarity of water molecules favored the polar growth of the precursor, resulting in the formation of n...

When tailored to make durable thermal barrier coatings (TBCs), the Solution Precursor Plasma Spray (SPPS) process produces a microstructure containing uniformly vertical cracks. These cracks provide a high degree of strain tolerance to the ceramic top coat. In order to understand the formation of vertical crack in SPPS process, coatings of various thicknesses were deposited on a variety of subs...

To explain the existence and observations of prebiotic molecules in interstellar and protostellar environments, it is first necessary to evaluate the chemical and physical processes that govern the generation, behavior, and destruction of precursor molecules, from which complex prebiotic species are probably formed. In interstellar and protostellar environments, many of these precursor species,...

Received December 30, 2001 A neuropeptide nociceptin or orphanin FQ (Noc/OFQ) was previously identified as an endogenous ligand for the orphan opioid receptor-like receptor. Studies on the analysis of the precursor of Noc/OFQ, we identified another novel neuropeptide and named it “nocistatin”. Noc/OFQ is involved in a broad range of pharmacological actions in various tissues from the central ne...

Solar cells consisting of an extremely thin In2S3/CuInS2 buffer/absorber layer uniformly covering planar ZnO were prepared entirely by chemical spray pyrolysis. Au nanoparticles (Au-NPs) were formed via thermal decomposition of a gold(III) chloride trihydrate (HAuCl4·3H2O) precursor by spraying 2 mmol/L of the aqueous precursor solution onto a substrate held at 260 °C. Current-voltage scans and...

Porous metallic copper was successfully prepared by a simple thermal decomposition strategy. A coordination compound of Cu(BTA)2 with the morphology of micro-rod crystal was synthesized as the precursor. The precursor to copper transformation was performed and annealed at 600°C with the shape preserved. The copper micro-rods are assembled from unique thin lamellar layers, each with the thicknes...