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91.
1 INTRODUCTIONWith the invention of lasers[1] and the observation of second-harmonic generation in quartz[2], nonlinear optics(NLO), as a cornerstone of photonics, has been booming since 1960's. And intense interest has been aroused to search materials exhibiting appropriate nonlinear optical properties suitable for the construction of practical optical devices for the important techniques such as frequency converting, signal processing and optical computing[3~6]. In order to determine … 相似文献
92.
SABen-Hao CAIXu TAIAn ZHOUDai-Mei 《理论物理通讯》2004,42(3):403-406
We present the simulation results of the net charge fluctuation in Au Au collisions at √Snn=130 GeV from a dynamic model, JPCIAE, and its revisions. The simulations are done for the quark-gluon matter, the directly produced pions, the pion matter, and the hadron matter. The simulated net charge fluctuation of the quark-gluon matter is close to the thermal model prediction for the quark-gluon gas. However, the discrepancy exists comparing the simulated net charge fluctuation for directly produced pions and the pion matter with the thermal model prediction for pion gas and the resonance pion gas, respectively. The net charge fluctuation of hadron matter from default JPCIAE simulations is nearly 3.5 times larger than quark-gluon matter. A discussion is given for the net charge fluctuation as an evidence of QGP phase transition. 相似文献
93.
Mary C. Salazar José L. Paz Antonio J. Hernández Carlos I Manzanares Eduardo V. Ludeña 《Theoretical chemistry accounts》2001,106(3):218-222
In the present contribution we report a study of the weakly bound van der Waals N2–He molecule in the framework of the supermolecule approach by means of the PWPW and mPW1PW exchange–correlation functionals,
using density functional theory local-spin-optimized atom-centered basis sets complemented with bond functions optimized at
the mPW1PW level of theory. Calculations show that the mPW1PW functional using bond functions gives a realistic representation
of the interaction-energy potentials for this van der Waals dimer, comparable to reference M?ller–Plesset perturbation theory
calculations. In contrast, the PWPW functional is unable to describe the bonding properties of this system and all values
of the bonding properties obtained at different geometries with this functional are considered out-of-scale compared with
the rest of the calculations presented in this study.
Received: 30 October 2000 / Accepted: 3 January 2001 / Published online: 3 April 2001 相似文献
94.
Kamantsev A. P. Amirov A. A. Koshkid’ko Yu. S. Mejía C. Salazar Mashirov A. V. Aliev A. M. Koledov V. V. Shavrov V. G. 《Physics of the Solid State》2020,62(1):160-163
Physics of the Solid State - Magnetocaloric effect (MCE) in pulsed magnetic fields up to 50 T was directly studied in alloy Fe49Rh51. An inverse MCE ΔT ≈ –8 K is observed at... 相似文献
95.
Akari Narayama Sosa Israel González Alejandro Trejo Álvaro Miranda Fernando Salazar Miguel Cruz-Irisson 《Journal of computational chemistry》2020,41(31):2653-2662
Recently, the need of improvement of energy storage has led to the development of Lithium batteries with porous materials as electrodes. Porous Germanium (pGe) has shown promise for the development of new generation Li-ion batteries due to its excellent electronic, and chemical properties, however, the effect of lithium in its properties has not been studied extensively. In this contribution, the effect of surface and interstitial Li on the electronic properties of pGe was studied using a first-principles density functional theory scheme. The porous structures were modeled by removing columns of atoms in the [001] direction and the surface dangling bonds were passivated with H atoms, and then replaced with Li atoms. Also, the effect of a single interstitial Li in the Ge was analyzed. The transition state and the diffusion barrier of the Li in the Ge structure were studied using a quadratic synchronous transit scheme. 相似文献
96.
U. Wagner F. E. Wagner A. Stockklauser R. Salazar J. Riederer F. Kauffmann-Doig 《Hyperfine Interactions》1986,29(1-4):1113-1116
A large number of ceramic sherds from Chavin, Peru, as well as recent clay samples from the same region have been studied by Mössbauer spectroscopy. The changes of the Mössbauer spectra of the clay were studied as a function of firing temperature and atmosphere. From a comparison of these data with those form the sherds one can make estimates of the precolumbian firing conditions. 相似文献
97.
In the framework of density functional theory (DFT), the electronic excitations and nonlinear optical (NLO) properties of six binuclear transition metal cluster anions with the formula of [Ch2M-(μ-Ch)2-M'CN]^2- (M = Mo, W; Ch = S, Se; M' = Cu, Ag) have been systemically investigated at both cases of gas phase and DMF solution. The obtained electronic absorption spectra reveal that the element replacements of metals M and ligands Ch have significant influence on the absorptions, especially on the low-lying ones. In addition, the transitions of μ-Ch→M are dominant for the low-lying excitations, whereas the transitions of M'→M as well as Ch→M are mainly responsible for the higher excitations. The calculated molecular first and second hyperpolarizabilities present the remarkable element substitution and solvent effects. The analyses show that the transitions involving μ-Ch→M charge transfer make the critical contributions to the first hyperpolarizability t, and that the charge transfers from the moieties of MCh4 to M'CN as well as those of μ-Ch→M and M'→M are responsible for the second hyperpolarizability y. Moreover, the introduction of solvent leads to the results that the transitions within the moieties of MCh4 and M'CN make larger contributions to the hyperpolarizability, especially to γ. 相似文献
98.
U. Wagner F. E. Wagner B. Marticorena R. Salazar R. Schwabe J. Riederer 《Hyperfine Interactions》1986,29(1-4):1117-1120
To obtain information on the firing of inca ceramics, 7 samples from different locations were studied by Mössbauer spectroscopy including a detailed laboratory refiring procedure. The glaze typical for the surface of this ware was studied by Mössbauer scattering. 相似文献
99.
U. Wagner W. Knorr A. Forster E. Murad R. Salazar F. E. Wagner 《Hyperfine Interactions》1988,41(1):855-858
An illite separated from mylonites from the southern rim of the Bohemian massif was studied by Mössbauer spectroscopy at temperatures between 300 and 1.8 K. The iron is mainly contained in oxides associated with the illite. Only 13% of the iron are structural Fe3+ and Fe2+ within the clay mineral matrix. The transformations of the oxidic iron during heating at temperatures up to 1250°C were followed by Mössbauer measurements at 300 and 4.2 K. 相似文献
100.
Loreto Salazar Julia Rubido Modesta Espada Carmen Pedregal Gregorio Trigo Jos Elguero 《Journal of heterocyclic chemistry》1986,23(2):481-485
N3-Substituted hydantoins have been to undergo lithium aluminum hydride reduction (THF, room temperature, 5 hours) to give 4-hydroxy-2-imidazolidinones in good yields. 相似文献