نتایج جستجو برای: absorption phase
تعداد نتایج: 722003 فیلتر نتایج به سال:
X-ray diffraction showed that an La7.0Mg75.5Ni17.5 alloy prepared via inductive melting was composed of an La2Mg17 phase, an LaMg2Ni phase, and an Mg2Ni phase. After the first hydrogen absorption/desorption process, the phases of the alloy turned into an La–H phase, an Mg phase, and an Mg2Ni phase. The enthalpy and entropy derived from the van’t Hoff equation for hydriding were −42.30 kJ·mol−1 ...
Phase retrieval extracts quantitative phase information from x-ray propagation-based phase-contrast images. Notwithstanding inherent approximations, phase retrieval using a single sample-to-detector distance (SDD) is very attractive, because it imposes no setup complications or additional radiation dose compared to absorption-based imaging. Considering the phase-attenuation duality (ε=δ/β, wher...
We report quantitative measurement of the relative proportion of δ- and β-D-mannitol crystalline phases inserted into polyethylene powder pellets, obtained by time-domain terahertz spectroscopy. Nine absorption bands have been identified from 0.2 THz to 2.2 THz. The best quantification of the δ-phase proportion is made using the 1.01 THz absorption band. Coherent detection allows using the spec...
We report on the detection of Ne viii in an intervening multiphase absorption line system at z = 0.32566 in the FUSE spectrum of the quasar 3C 263 (zem = 0.646). The Ne viii λ770 Å detection has a 3.9 σ significance. At the same velocity we also find absorption lines from C iv, O iii, O iv and N iv. The line parameter measurements yield log [N(Ne viii) cm] = 13.98 −0.13 and b = 49.8± 5.5 km s ....
PURPOSE Small-animal studies require images with high spatial resolution and high contrast due to the small scale of the structures. X-ray imaging systems for small animals are often limited by the microfocus source. Here, the authors investigate the applicability of liquid-metal-jet x-ray sources for such high-resolution small-animal imaging, both in tomography based on absorption and in soft-...
The pressure–composition (PC) behavior of deuterium in single crystal Pd has been measured over a temperature range extending from room temperature to 393 K. These data allow the determination of (i) relative partial molar enthalpy and entropy, without the contribution of the configuration entropy, for the dilute solid solution phase, (ii) enthalpy and entropy change characterizing the a→a9 pha...
The accurate, quantitative analysis of absorption and scattering properties in tissue is a central problem in biochemical optics, in particular for the determination of hemoglobin and oxyhemoglobin concentrations. Because of light scattering, the absolute concentrations of these chromophores (i.e., the absorption coefficient) cannot easily be inferred. A new method for the estimation of the abs...
Kinetics of P absorption were investigated in mycorrhizal (Glomus fasciculatus) and nonmycorrhizal tomato (Lycopersicon esculentum) roots to determine why increased ion absorption by mycorrhizae occurs. Initial rates of absorption of (32)P were measured at 1 to 100 micromolar KH(2)PO(4) (pH 4.6). Absorption rates of mycorrhizae were about twice those of control roots. Augustinsson-Hofstee analy...
Absorption cross-sections and quantum yields for NO2 production (ΦNO2) are reported for gaseous methyl, ethyl, n-propyl, and isopropyl nitrate at 294 K. Absorption cross-sections in the wavelength range of 240-320 nm agree well with prior determinations. NO2 quantum yields at photoexcitation wavelengths of 290, 295, and 315 nm are unity within experimental uncertainties for all of the alkyl nit...
this new method which is worked out in isfahan university of technology, makes it possible to analyze the phases quantitatively in minerals and powdered materials by x ray diffraction and without any reference material. to identify n unknown phases, n different combinations of phases, from fine and coarse fractions, or etc., must be obtained. amorphous phases should not exist. intensity ratios ...
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