Study on the Phase Diagram of CsCl-CeCl3-HCl(11%)-H2O System and the Properties of the Compounds

The equilibrium solubility of CsCl-CeCl3-HCl(11%)-H2O qua-ternary system at 25℃ has been determined by the physicchemical analysis method ,and the phase diagram was plotted, Two new double salts 3CsCl.CeCl3.3H2O and CsCl.CeCl3.4H2O obtained from the complicated system were identified and characterized by XRD,TG-DTA ,DSC,UV and fluorescence spectroscopy, Studies on the fluorescence excitation and emission show that 3CsCl.CeCl3.3H2O and CsCl.CeCl3.4H2O have upconversion luminescence of infrared-visible range,and the upconversion emission intensity increases with the increase of ratio of CeCl3 in CsCl.     

The Effect of Vibrational Excitation of Molecules on Plasmachemical Reactions Involving Methane and Nitrogen

An experimental study of plasmachemical reaction involving CH₄ and N₂ molecules in rf discharge was studied in order to know the effect of vibrational excitation of N₂ molecules. When the relative nitrogen concentration was greater than 0.8, the main product of CH₄ decomposition was HCN, and the rate of methane decomposition at this condition was faster than that one in pure methane. These results could be confirmed through the mass spectroscopic method. The reason for these results is the vibrational energy of N₂ excited by rf discharge. The chain reaction mechanisms of producing HCN by vibrational excitation of N₂ were examined closely through numerical simulation. The rate-controlling step was the dissociation reaction of excited nitrogen molecule to the atomic nitrogen, so the process of HCN synthesis was limited by the value of reaction constant, k^N.     

Surface-enhanced Raman scattering studies on the adsorption of p-nitrobenzoic acid at Au electrode under different potential with ultraviolet excitation

The potential-dependent surface-enhanced Raman spectrum of adsorbed p-nitrobenzoic acid (PNBA) on the roughened Au electrode has been obtained by using ultraviolet (UV) excitation at 325 nm. The surface-enhanced Raman spectra of PNBA intensely changed when the voltage was in the rang of negative value, and the electrode potential at which the resonance (potential of maximum intensity) occurs varied when the vibrational mode changes, indicating that the PNBA molecules were chemisorbed on the roughened Au surface. The charge transfer (CT) mechanism could probably explain the experiment results in the present work.     

The relative importance of temperature and isotope effects on the dipole oscillator strength distribution of H2

Summary The calculation of the effects of temperature and isotopic composition on the energy weighted moments of the dipole oscillator strength distribution of H₂ in the random phase approximation to the polarization propagator are reported. It is seen that the effect of isotopic composition is small, while that of temperature is of an order accessible to experiment. We find that all the mean excitation energiesI , for =–1, 0, 1, decrease with temperature as does the dipole oscillator strength momentS() for >0, while the opposite is true for <0. These effects are interpreted in terms of the bond length dependence of the excitation energies.     

Spectro-streak picosecond studies of intramolecular charge-transfer fluorescence

A spectro-streak photometer, an instrument for simultaneously measuring fluorescence intensity, time, and wavelength,I(t, ), with a single picosecond excitation pulse, has been constructed. Two typical and currently highly topical examples of mesurements are discussed. (1) the temporal development of the fluorescence form the intramolecular charge-transfer (ICT) state of the rigid aromatic compound 4,5-(1-methylindolino)3,4-naphthanthracene is studied in the protic solvent hexanol. (2) Propyl chain-linked pyrene/N,N-dimethylaniline is used as the model compound to study conformational changes associated with the transition from a contact ion pair to a sandwich exciplex.     

一种新型的无刷同步电动机

改进逆序串激式无刷同步电动机在结构上和电气上的缺点,提出一种新型的励磁方式,以获得结构和电气性能更优的无刷同步电动机。方法应用 自控和斩波技术,实现励磁电流的自动调节。     

A recording phase lag between ocean and continent climate changes: Constrained by the Matuyama/Brunhes polarity boundary

The Matuyama/Brunhes polarity boundary (MBPB) is recorded in Chinese loess L8, which is associated with the glacial period. It is proved that loess L8 is capable of recording earth’s secular variation, and the lock-in depth in Chinese loess is no more than that of marine sediments. Comparison with the location of MBPB in Chinese loess and marine sediments, it is put forward that there is a recording phase lag between ocean and continent climate changes.     

一种线性化与变结构相混合的发电机励磁控制器

以电力系统的非线性数学模型为基础,根据直接反馈线性化与滑模变结构控制理论,提出了一种旨在提高电力系统稳定性的由直接反馈线性化与滑模变结构混事控制完成的电力系统同步发电机励磁控制器,仿真研究表明,所提出的励磁控制器不仅可以有效地改善系统的动态品质,而且在提高电力系统的稳定性,尤其是大干扰稳定性方面有明显的作用。     

MULTIPHOTON EXCITATION OF A WATER MOLECULE IN INTENSE LASER FIELDS

A stretch vibration Hamiltonian of H_2O has been derived by using the second quantization, unitary transformations and the optimization of coefficients. The energy spectrum obtained from this Hamiltonian is in good agreement with that of experiments. The multiphoton excitation and the energy absorption of H_2O in intense laser fields have been calculated.     

Design of a new molecule that exhibits observable CD spectra under σ-σ* excitation: 2,6-Disilyl-2,6-disilaspiro[3.3]heptanes

Abstract

We previously designed and prepared the first molecules to exhibit observable CD spectra by n-σ* excitation, 2,6-dithiaspiro[3.3]heptane 2,6-dioxide. Spiro[3.3]heptane frameworks possess axial asymmetry due to puckering of 2 four-membered rings; the ring bonds are rich in p-character due to acute bond angles, which lowers the σ* energy levels. In contrast, the lone pairs are rich in s-character, which results in a good donor with conformational fixation. We expected that, instead of lone pairs as donating orbitals, the use of σ-electron-donating Si-Si bonds should result in UV absorption in the observable range (>180?nm), so that the Cotton effect could appear, at least partially, in that range. We designed 2,6-disilyl-2,6-disilaspiro[3.3]heptanes as models, and performed theoretical calculations to confirm our idea.