Kong Xiang-He

Optical and Electrical Properties Evolution of Diamond-Like Carbon Thin Films with Deposition Temperature

Optical and electrical properties of diamond-like carbon (DLC) films deposited by pulsed laser ablation of graphite target at different substrate temperatures are reported. By varying the deposition temperature from 400 to 25° C, the film optical transparency and electrical resistivity increase severely. Most importantly, the transparency and resistivity properties of the DLC films can be tailored to approaching diamond by adjusting the deposition temperature, which is critical to many applications. DLC films deposited at low temperatures show excellent optical transmittance and high resistivity. Over the same temperature regime an increase of the sp3 bonded C content is observed using visible Raman spectroscopy, which is responsible for the enhanced transparency and resistivity properties.

The problems of the nonlinear unsymmetrical bending for cylindrically orthotropic circular plate (II)

In this paper, the problems of nonlinear unsymmetrical bending for cylindrically orthotropic circular plate are studied by using “the method of two-variable”[1], and the uniformly valid asymptotic solutions of Nth-order for ε1 and Mth-order for ε2 are obtained

One-colour resonant two-photon ionization spectrum of the 1-fluoronaphthalene dimer and ab initio calculation

The one-colour resonant two-photon ionization (R2PI) spectrum of the 1-∞uoronaphthalene (1FN) dimer has been studied in the wavelength range of 304 to 322 nm by using a supersonic molecular beam and time-of-∞ight mass spectrometry. Compared with the original band 0 0 (at 313.8 nm) of the S1 ˆ S0 transition of the 1FN monomer, a red-shifted band was observed in the 1FN dimer spectrum at about 315 nm with a relatively large linewidth, nearly 2 nm. Based on the consideration of inductive efiect and ab initio calculations, this red-shifted band is assigned to the flrst electronic excited transition of the 1FN dimer. A possible geometric structure of the 1FN dimer is also obtained with calculations that the two 1FN molecules are combined through two hydrogen bonds which are formed between the hydrogen atom of a molecule and the ∞uorine atom of a neighbouring molecule. A time-dependent calculation was also carried out and the results are consistent with the experimental data.

Multiphoton Ionization Mass Spectrum of Methanol Clusters and Ab Initio Calculations

Multiphoton ionization mass spectrum of methanol clusters was studied by using pulsed 355 nm laser to ionize supersonic molecular beam.Besides some fragment ions of methanol,protonated methanol cluster ions(CH3OH)nH+(n=1-16)were observed and the clusters intensity distribution was not affected by laser delay time relative to pulsed molecular beam,which implied that the ions species and intensity were determined only by clusters inherent geometric stability.Possible stable geometry structures of(CH3OH)n and(CH3OH)nH+(n=1-4)were obtained by using ab initio calculation at B3LYP/6-31G(d)basis level.Comparing clusters infrared vibrational spectrum with related atomic motion image,it was found that the main contribution to the strongest IR mode came from the H stretch vibration of the hydrogen bond.Proton transfer reaction occurred within clusters after ionization possibly corresponded with the excitation of vibrational mode which is related to hydrogen bond.