Highly Thermal Conductive Graphite Films Derived from the Graphitization of Chemically Imidized Polyimide Films.

With the large-scale application and high-speed operation of electronic equipment, the thermal diffusion problem presents an increasing requirement for effective heat dissipation materials. Herein, high thermal conductive graphite films were fabricated via the graphitization of polyimide (PI) films with different amounts of chemical catalytic reagent. The results showed that chemically imidized PI (CIPI) films exhibit a higher tensile strength, thermal stability, and imidization degree than that of purely thermally imidized PI (TIPI) films.

Preparation of Nitrogen-Doped Cellulose-Based Porous Carbon and Its Carbon Dioxide Adsorption Properties.

Nitrogen-doped cellulose-based porous carbon materials were obtained by hydrothermal method and KOH chemical activation together with melamine as a nitrogen-doping precursor. The effects of hydrothermal temperature on the microstructure and surface morphology of the products were mainly studied. Also, the carbon dioxide adsorption capacity of the prepared porous carbon was investigated.

Preparation and Electrical Properties of Polyacrylonitrile Based Porous Carbon by Different Activation Methods.

Polyacrylonitrile (PAN)-based porous carbon was prepared by different methods of activation with PAN polymer microsphere as precursor. The morphology, structure and electrical properties for supercapacitor of the porous carbon were investigated. It was found that the morphology of PAN nanospheres tended to be destroyed in the process of one-step activation (activation and carbonization were carried out simultaneously, and could only be retained when the amount of activating agent KOH was small).

[Study on the Turning Effect of the Energy Gap of π Electron on Atomic Vibration in Conjugated Linear Polymer].

The Visible absorption and Raman spectra of β-carotene were measured in dimethyl sulfoxide in temperature ranging from 81 to 25 ℃ and in carbon disulfide in pressure range from 0.04 to 0.60 GPa, respectively.

[The Effect of the Phase on Characteristic Energy of All-Trans-β-Carotene].

All-trans-β-carotene has important functions of light collection and light protection, and it is also an important electrooptical material. The Raman spectra of polyenes are a result of the modulation effect of the π electron energy gap on the vibration of CC bonds, which associate with the external field. So it has higher theoretical significance and practical value to study the molecular structure and properties change under the external field.

[Resonance Raman Spectral Properties Studies of Beta-carotene in Solution].

Beta-carotene is an important kind of polyene biomolecules, which has significant applications on researching optoelectronic and functional materials. In-situ high pressure Raman spectra of beta-carotene are measured in CS2 solution and water respectively at pressure range from 0-0.60 GPa.

[Effect of pressure on electron-phonon coupling constants of all-trans-beta-carotene].

The present paper cited that R Tubino and other people introduced a kind of electron-phonon coupling constants with dimension, which can establish the relation with the Huang-Rhys factor and calculate the electron-phonon coupling constants of every C-C bond vibration mode. There are many reports about the visible absorption and Raman spectra of all-trans-beta-carotene with pressure. But the study about the Raman scattering cross section and the Huang-Rhys factor with pressure have not been reported now.

Phase-dominant pressure-induced planar molecular conformation of S-trioxane.

In situ high-pressure Raman spectra of S-trioxane have been measured up to 28 GPa. A first-order phase transition was detected at ~3 GPa from the splitting, newly existing and diminishing of the internal modes and from changes in the slope on plots of frequency versus pressure. The vibrational spectra and theoretical simulation indicate that the isolated molecule structure changes from puckered to very puckered structure at the first phase, while at the beginning of the second phase, S-trioxane goes back to its original puckered structure and loses its C3 axis; then, it changes to planar structure at about ~GPa and keeps its flat structure in the second phase up to the highest pressure studied.

Phase-transition induced changes in the electron-phonon coupling of all-trans-β-carotene.

The resonance Raman spectra of the fundamental, combination, and second harmonic modes around the C-C and C=C stretches of all-trans-β-carotene in 1,2-dichloroethane solution are obtained in the 323-83 K temperature range. The Raman scattering cross-section of the fundamentals in the liquid and solid phases generally increases as the temperature decreases, except for the liquid-solid phase transition, which exhibits a decreasing trend. The relative Raman intensities of the combination and harmonic modes of the CC bonds increase as the temperature decreases.