We assume implicitly that X-rays interact with atoms in their ground state when we analyze data obtained by X-ray diffractometry or spectroscopy. Now, the success of X-ray free-electron lasers (XFEL) challenges this "common sense." A femtosecond flush of XFEL provides X-ray photons comparable to those generated by SPring-8 undulator beamlines over one second. Such high intensity X-rays may be a...

Gated and streak cameras have been used to look at a high current focused electron beam on a target, and the x-rays produced by that interaction. An optical camera images the optical transition radiation (OTR) from the beam hitting a carbon target to give focused beam profiles. Blackbody radiation from heavy metal targets is experimentally proven to be dominant. The roll bar technique is used a...

Star formation and supermassive black hole growth in galaxies appear to be self-limiting. The mechanisms for self-regulation are known as feedback. Cosmic rays, the relativistic particle component of interstellar and intergalactic plasma, are among the agents of feedback. Because cosmic rays are virtually collisionless in the plasma environments of interest, their interaction with the ambient m...

in this study silver/poly vinyl alcohol (pva) and silver/poly vinyl pyrrolidone (pvp) nanocomposites were prepared via reduction of silver salt by employing dmf (n, n`- dimethyl formamide) as a reducing agent. effects of protective agents such as pva and pvp were also described here. we show that the acidic ph of pvp solution also affects the interaction between protective agents and silver nan...

The effects of stigmasterol, sitosterol, campesterol, and cholesterol on the phase properties of dipalmitoylphosphatidylcholine bilayers have been compared by differential scanning calorimetry and x-ray diffraction. The sterols were equally effective at progressively reducing the cooperativity and the enthalpy of the dipalmitoylphosphatidylcholine phase transition as their concentrations in the...

the output of x-ray, especially in the field of required energy for diagnosing the disease is very low (in diagnosing lamps, it is less than 1%). in this kind of lamps the rest of the electrical energy is transformed to heat. this considerable amount of heat induces a myriad of too many limitations in choosing higher levels of radiation, particularly in specialized techniques. this process is t...

background: social capital causes promoting community members’ participation level as set of norms among community systems. we aimed to determination between perceived social capital with relevant factors among health workers in medical and health network of rey city.   methods: this study was a cross sectional one which assessed determination between social capital and relevant factors among h...

background: panoramic imaging is one of the most common imaging methods in dentistry. regarding the side-effects of ionizing radiation, it is necessary to survey different aspects and details of panoramic imaging. in this study, we compared the absorbed x-ray dose around two panoramic x-ray units: pm 2002 cc proline (planmeca, helsinki, finland) and cranex tome (soredex, helsinki, finland). mat...

We discuss two themes from Chandra cluster observations. First, we describe the interaction of buoyant, radio emitting plasma bubbles with the hot intracluster gas. Second we summarize the Chandra observations of "cold" fronts (sharp discontinuities in gas density and temperature) separating cool, denser gas clouds from the hotter intracluster medium. 1. The Radio — X-ray Interaction or Bubbles...