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171.
M. R. Beghoul B. Fougere A. Boudrioua C. Darraud S. Latreche R. Kremer P. Moretti J. C. Vareille 《Optical and Quantum Electronics》2007,39(4-6):333-340
In this work, we report the investigation of 2D photonic crystals in lithium niobate associated with waveguiding structures
fabricated by He+ implantation. From the material point of view, the investigation of PBG structures in lithium niobate is of great interest
for optoelectronics technology since this crystal is one of the most important materials widely used in integrated and non
linear optics. The choice of the implantation technique to produce the waveguide is motivated by the possibility of having
both Transverse Electric (TE) and Transverse Magnetic (TM) guided modes in order to obtain a total photonic band gap (PBG). 相似文献
172.
173.
Stefano Moretti 《Zeitschrift fur Physik C Particles and Fields》1997,75(3):465-469
Irreducible background effects due to e + e ? → W ± + bbjj and e + e ? → W ± + jjjj events produced via QCD in top-antitop production and heavy Higgs searches in the bremsstrahlung channel are studied at the Next Linear Collider. Various distributions relevant to phenomenological analyses are given and compared to those expected from top and Higgs signals in the decay channel bb?W + W ? → bb?W ± jj. This analysis follows similar ones previously carried out for the case of the irreducible background proceeding via electroweak interactions 相似文献
174.
The polarity of carbon layer open tubular (CLOT) columns coated with a layer of non-porous graphitized carbon black (Carbopack B) modified with an appropriate amount of polar polyglycol liquid phase has been evaluated and compared with that of standard polar (Supelcowax-10) and non-polar (SPB-1) bonded phase open tubular columns. The efficiency and selectivity were measured at various temperatures and the polarity of the columns was evaluated by use of McReynolds' constants and the difference in apparent carbon number, ΔC of linear alkanes and alcohols. The polarity of the CLOT column was found to depend on temperature, and changing the analytical conditions therefore enabled the separation of compounds of different polarity whose reciprocal position and resolution were affected by temperature. The application of calculation methods which enable programmed temperature retention times to be predicted from isothermal data was also found to be possible when the polarity of the CLOT column changes with temperature. 相似文献
175.
E. M. Telles J. C. S. Moraes A. Scalabrin D. Pereira A. Moretti F. Strumia 《Applied physics. B, Lasers and optics》1991,52(1):36-41
In this work we report new FIR laser lines from CD3OD optically pumped by a CO2 waveguide laser. The wide tunability of this laser (290 MHz) makes it possible to pump absorption lines with large frequency offset relative to the CO2 laser line center, which are not possible by using conventional CO2 lasers. As a consequence 19 new laser lines have been discovered, ranging from 38.0 m to 455.2 m in wavelength. For all lines, precise frequency offset measurements between the CO2 line center and the center of the absorber CD3OD line were performed using the transferred Lamb-dip technique. We also present direct Doppler-free offset measurements of infrared absorption, obtained within the FIR laser cavity itself, using optoacoustic detection.Work supported by FAPESP, CNPq, FAP-Brasil and CNR-Italy 相似文献
176.
Valter?Moretti Nicola?PinamontiEmail author 《Communications in Mathematical Physics》2012,309(2):295-311
Tunnelling processes through black hole horizons have recently been investigated in the framework of WKB theory, discovering
an interesting interplay with Hawking radiation. In this paper, we instead adopt the point of view proper of QFT in curved
spacetime, namely, we use a suitable scaling limit towards a Killing horizon to obtain the leading order of the correlation
function relevant for the tunnelling. The computation is done for a certain large class of reference quantum states for scalar
fields, including Hadamard states. In the limit of sharp localization either on the external side or on opposite sides of
the horizon, the quantum correlation functions appear to have thermal nature. In both cases the characteristic temperature
is referred to the surface gravity associated with the Killing field and thus connected with the Hawking one. Our approach
is valid for every stationary charged rotating non-extremal black hole. However, since the computation is completely local,
it covers the case of a Killing horizon which just temporarily exists in some finite region, too. These results provide strong
support to the idea that the Hawking radiation, which is detected at future null infinity and needs some global structures
to be defined, is actually related to a local phenomenon taking place even for local geometric structures (local Killing horizons),
existing just for a while. 相似文献
177.
The evaluation and prediction of the shape of asymmetric gas chromatographic peaks is important as the knowledge of the amount of tailing permits to foresee the resolution between closely eluting peaks and to select the best analytical conditions for an efficient and rapid separation. A model function was tested in order to approximate the true peak shape obtained on non-polar column by injecting different compounds. The trend of the parameters involved in the used equation has been investigated as a function of column temperature and inlet pressure. The reproduction of the symmetrical or asymmetrical shape of gas chromatographic peaks is satisfactory and the method also permits to predict the shape of peaks obtained in different conditions of temperature and pressure. 相似文献
178.
N. Ioli A. Moretti G. Moruzzi F. Strumia F. D'Amato 《International Journal of Infrared and Millimeter Waves》1985,6(10):1017-1029
8 new large offset FIR laser lines of CH2F2 have been discovered by pumping with a high tunability waveguide CW CO2 laser. Optoacoustic measurements of CH2F2 have also been performed and the pump offsets of the new and of previously known lines have been measured and checked. Some assignments are proposed and a few assignments found in literature are checked 相似文献
179.
We show how the LHC potential to detect a rather light CP-even Higgs boson of the NMSSM, H1 or H2, decaying into CP-odd Higgs states, A1A1, can be improved if Higgs-strahlung off W bosons and (more marginally) off top–antitop pairs are employed alongside vector boson fusion as production modes. Our results should help extracting at least one Higgs boson signal over the NMSSM parameter space. 相似文献
180.
We implement matrix-element corrections to HERWIG parton shower simulations for Standard Model Higgs boson production at hadron colliders. We study the Higgs transverse momentum distribution and compare different versions of HERWIG and resummed calculations. The HERWIG results exhibit a remarkable improvement as many more events are generated at large transverse momentum after the inclusion of matrix-element corrections. 相似文献