Big Chemical Encyclopedia

Chemical substances, components, reactions, process design ...

Articles Figures Tables About

Excitability-inducing material

EM (excitability-inducing material) and BWSV (black widow spider venom)... [Pg.9]

In the continuum domain, we now understand [25] that control over multiply degenerate states, leading to the final products of interest, can be attained only if we can establish an entanglement between the photons used to excite a material system and the material system itself. Entanglement in this context means that light-induced transition amplitudes cannot be factorized into products of material and radiative matrix elements. The usefulness of CC and AP is that these are general methods that can be applied to an entire... [Pg.129]

Structure defects decrease conductivity of the studied material, and then the intensity of the induced magnetic field is small and the signal received by the probe Hp is big (Fig.2). Low conductivity of austenite is a defects of the structure in case of residual austenite in the martensite structure, which with regard to the magnesite structure is as 1 5. Eddy currents produced in the studied area are subject to excitation in effect of small conductivity of austenite grains in the structure of the studied material. [Pg.20]

The higher-order bulk contribution to the nonlmear response arises, as just mentioned, from a spatially nonlocal response in which the induced nonlinear polarization does not depend solely on the value of the fiindamental electric field at the same point. To leading order, we may represent these non-local tenns as bemg proportional to a nonlinear response incorporating a first spatial derivative of the fiindamental electric field. Such tenns conespond in the microscopic theory to the inclusion of electric-quadnipole and magnetic-dipole contributions. The fonn of these bulk contributions may be derived on the basis of synnnetry considerations. As an example of a frequently encountered situation, we indicate here the non-local polarization for SFIG in a cubic material excited by a plane wave (co) ... [Pg.1279]

In photoluminescence one measures physical and chemical properties of materials by using photons to induce excited electronic states in the material system and analyzing the optical emission as these states relax. Typically, light is directed onto the sample for excitation, and the emitted luminescence is collected by a lens and passed through an optical spectrometer onto a photodetector. The spectral distribution and time dependence of the emission are related to electronic transition probabilities within the sample, and can be used to provide qualitative and, sometimes, quantitative information about chemical composition, structure (bonding, disorder, interfaces, quantum wells), impurities, kinetic processes, and energy transfer. [Pg.29]

Three techniques involving the use of X-ray emission to obtain quantitative elemental analysis of materials are described in this chapter. They are X-Ray Fluorescence, XRF, Total Reflection X-Ray Fluorescence, TXRF, and Particle-Induced X-Ray Emission, PIXE. XRF and TXRF use laboratory X-ray tubes to excite the emission. PIXE uses high-energy ions from a particle accelerator. [Pg.335]

The intrinsic drawback of LIBS is a short duration (less than a few hundreds microseconds) and strongly non-stationary conditions of a laser plume. Much higher sensitivity has been realized by transport of the ablated material into secondary atomic reservoirs such as a microwave-induced plasma (MIP) or an inductively coupled plasma (ICP). Owing to the much longer residence time of ablated atoms and ions in a stationary MIP (typically several ms compared with at most a hundred microseconds in a laser plume) and because of additional excitation of the radiating upper levels in the low pressure plasma, the line intensities of atoms and ions are greatly enhanced. Because of these factors the DLs of LA-MIP have been improved by one to two orders of magnitude compared with LIBS. [Pg.234]

The last problem of this series concerns femtosecond laser ablation from gold nanoparticles [87]. In this process, solid material transforms into a volatile phase initiated by rapid deposition of energy. This ablation is nonthermal in nature. Material ejection is induced by the enhancement of the electric field close to the curved nanoparticle surface. This ablation is achievable for laser excitation powers far below the onset of general catastrophic material deterioration, such as plasma formation or laser-induced explosive boiling. Anisotropy in the ablation pattern was observed. It coincides with a reduction of the surface barrier from water vaporization and particle melting. This effect limits any high-power manipulation of nanostructured surfaces such as surface-enhanced Raman measurements or plasmonics with femtosecond pulses. [Pg.282]

The chemistry and physics of dendritic compounds started a decade ago [1-5]. Today, this science of uniquely shaped molecules, namely, dendrite-shaped molecules, is one of the most exciting topics of contemporary interdisciphnary research. The dendrimers and their related molecules have been investigated widely not only from the viewpoints of synthetic, physical, and material chemistries but also from that of mathematics. Accompanying the development of the science in this decade, research interest has shifted from the mere challenge of preparing molecules with unique shapes, via their excited state chemistries involving inter- and/or intramolecular photo-induced electron and/or energy transfer, to the nanoscience. [Pg.66]


See other pages where Excitability-inducing material is mentioned: [Pg.109]    [Pg.388]    [Pg.109]    [Pg.388]    [Pg.283]    [Pg.284]    [Pg.270]    [Pg.73]    [Pg.214]    [Pg.224]    [Pg.370]    [Pg.183]    [Pg.183]    [Pg.486]    [Pg.146]    [Pg.94]    [Pg.265]    [Pg.393]    [Pg.1204]    [Pg.288]    [Pg.125]    [Pg.126]    [Pg.114]    [Pg.428]    [Pg.433]    [Pg.28]    [Pg.322]    [Pg.221]    [Pg.132]    [Pg.585]    [Pg.227]    [Pg.314]    [Pg.93]    [Pg.199]    [Pg.99]    [Pg.92]    [Pg.402]    [Pg.138]    [Pg.161]    [Pg.58]   
See also in sourсe #XX -- [ Pg.99 ]




SEARCH



© 2024 chempedia.info