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排序方式: 共有473条查询结果,搜索用时 15 毫秒
91.
Martin Ziegler Karlheinz Ochs Mirko Hansen Hermann Kohlstedt 《Applied Physics A: Materials Science & Processing》2014,114(2):565-570
In nature, the capability of memorizing environmental changes and recalling past events can be observed in unicellular organisms like amoebas. Pershin and Di Ventra have shown that such learning behavior can be mimicked in a simple memristive circuit model consisting of an LC (inductance capacitance) contour and a memristive device. Here, we implement this model experimentally by using an Ag/TiO2?x /Al memristive device. A theoretical analysis of the circuit is used to gain insight into the functionality of this model and to give advice for the circuit implementation. In this respect, the transfer function, resonant frequency, and damping behavior for a varying resistance of the memristive device are discussed in detail. 相似文献
92.
Lo Giudice A Re A Angelici D Calusi S Gelli N Giuntini L Massi M Pratesi G 《Analytical and bioanalytical chemistry》2012,404(1):277-281
Broad beam ionoluminescence (IL) microscopy is a promising technique for the non-destructive characterisation of rocks and stone objects. Luminescence imaging by means of broad ion beams has been sporadically used by other authors but, to our knowledge, its potential has not yet been fully investigated, neither in geological science nor in other fields. The in-air broad beam IL microscope was developed and installed at the INFN-LABEC external microbeam in Florence. Similar to the cathodoluminescence (CL) microscope, the apparatus exploits a CCD colour camera collecting images (few square millimetres wide, with ~10-μm spatial resolution) of the luminescence emitted by the sample hit by a defocused megaelectron volt (MeV) proton beam. The main differences with the well-established and widespread CL are the possibility of working in air (no sampling or conductive coatings required) and the possibility of combining the analysis with microbeam analysis, such as, for example, μ-IL and μ-PIXE (particle-induced X-ray emission). To show the potential of the technique, IL images of thin sections of lapis lazuli are compared with those obtained by means of an in-vacuum cold CL. An application to the study of stone artworks is also reported. This technique and apparatus will provide a valuable help for interdisciplinary applications, e.g. in geological sciences and in the cultural heritage field. 相似文献
93.
94.
Adrenocortical carcinoma (ACC) is a rare malignancy with an incompletely understood pathogenesis and a poor prognosis. The adrenalytic activity of mitotane has made it the most important single drug in the treatment of ACC. Unfortunately, the exact mechanism of mitotane action is still unknown. It is believed that mitotane belongs to the class of drugs that require metabolic transformation by cytochrome P450 for therapeutic action; therefore determination of plasma levels of not only mitotane but also its metabolites would help in carrying out the treatment. The objective of this work was to develop and validate an SPE‐HPLC method for simultaneous determination of mitotane and its metabolites in different biological fluids. The sample preparation consisted of a solid‐phase extraction on a Discovery DSC18 cartridge, while analysis of extracts was performed on a Symmetry C18 column. The usefulness of the proposed method was confirmed by analysis of plasma, red cell and urine samples from patient chronically treated with 1.5 g of mitotane. The patient involved in this study had a high plasma concentration of mitotane and none of the investigated metabolites were found. In order to investigate whether the polymorphism of CYP2C9 and CYP2C19 enzymes could be related to the metabolism of mitotane, RT‐PCR analysis was performed. Copyright © 2012 John Wiley & Sons, Ltd. 相似文献
95.
Christian Fiebig J?rg Fricke Mirko Uebernickel Daniel Jedrzejczyk Alexander Sahm Katrin Paschke 《Optical Review》2012,19(6):405-408
Large-area high-resolution displays, using a flying-spot to create the picture, require light sources in the red, green and blue wavelength range with a high optical output power and nearly diffraction limited beam. In this paper we present experimental results of high-brightness distributed Bragg reflector tapered diode lasers at 106x nm that can be used for single-pass second harmonic generation into the green. Based on these lasers we developed compact (2.5 cm3) green laser modules with an output power of 1W at 53x nm and an electro-optical conversion efficiency of about 5%. The output power stability is better than 2% and the wavelength stability is ±10 pm. The excellent beam quality M ?? 2 < 2 of the green light allows operation in flying spot application systems. Furthermore, we estimate that our concept allows power scaling up to 2W by using nonlinear planar waveguide crystals and into the multi-watt level by spectral beam combining. 相似文献
96.
Bonneau D Lobino M Jiang P Natarajan CM Tanner MG Hadfield RH Dorenbos SN Zwiller V Thompson MG O'Brien JL 《Physical review letters》2012,108(5):053601
We demonstrate fast polarization and path control of photons at 1550?nm in lithium niobate waveguide devices using the electro-optic effect. We show heralded single photon state engineering, quantum interference, fast state preparation of two entangled photons, and feedback control of quantum interference. These results point the way to a single platform that will enable the integration of nonlinear single photon sources and fast reconfigurable circuits for future photonic quantum information science and technology. 相似文献
97.
Jerković I Gašo-Sokač D Pavlović H Marijanović Z Gugić M Petrović I Kovač S 《Molecules (Basel, Switzerland)》2012,17(2):2058-2072
GC and MS were used for the analysis of Croatian Centaurium erythraea Rafn essential oil (obtained by hydrodistillation) and headspace (applying headspace solid-phase microextraction). The headspace contained numerous monoterpene hydrocarbons (the major ones were terpinene-4-ol, methone, p-cymene, γ-terpinene and limonene). Oxygenated monoterpenes were present in the headspace and oil, while 1,8-cineole, bornyl acetate and verbenone were present only in the headspace. High headspace percentages of toluene and naphthalene were found, followed by hemimellitene. Lot of similarities were observed with Serbian C. erythraea oil [neophytadiene (1.4%), thymol (2.6%), carvacrol (6.1%) and hexadecanoic acid (5.7%)], but different features were also noted such as the presence of menthol, menthone and phytone. The oil fractionation enabled identification of other minor compounds not found in total oil such as norisoprenoides, alk-1-enes or chromolaenin. The essential oil showed antimicrobial potential on Escherichia coli, Salmonella enteritidis, Staphylococcus aureus and Bacillus cereus. On the other hand, no antibacterial activity of the oil was observed on Pseudomonas fluorescens and Lysteria monocytogenes. 相似文献
98.
The goal of this work is the simulation of concentration and temperature distributions insides fluidized bed with a uniform liquid distribution. Further, a physically based 2D model is developed for the heat and mass transfer processes in fluidized beds with a spray nozzle. The model is a coupled and semi-linear system of convection-reaction-diffusion equations. We considered the numerical solution of these semi-linear partial differential equations with discrete boundary conditions using linear finite elements on an adaptive triangular grid in space and implicit methods in time. We present calculations using, semi implicit and implicit methods in time, and different solvers for solving the linear systems. The complex correlations of mass and liquid flow rates, mass transfer, heat transfer, drying, and transient two dimensional air humidity, air temperature, degree of wetness, liquid film temperature and particle temperature were simulated. (© 2006 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim) 相似文献
99.
100.
JPC – Journal of Planar Chromatography – Modern TLC - Experiments and calculations show the importance of analytical management to reliable analytical results. A method with a... 相似文献