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Fourier transform infrared (FTIR) was exploited to measure terahertz (THz) spectra in the wave number range of 30-300 cm(-1) for saturated straight chain organic molecules at room temperature. The results reveal that different organic functional groups exhibit different THz spectral characteristics. The absorption peaks of vibration modes of organic crystal lattice locate in high frequency range of THz, while those of vibration modes of intermolecular hydrogen (H) bonds appear in low frequency range of THz. Moreover, a typical absorption peak of intermolecular H bonds caused by saturated straight-chain monohydric alcohol hydroxyl functional groups locates at 57 cm(-1), while a characteristic absorption peak of intermolecular hydrogen bonds caused by triacontanoic acid carboxyl functional groups appears at 74 cm(-1). The intermolecular H bonds not only result in that the THz absorbing abilities of triacontanol and triacontanoic acid are significantly stronger than that of triacontane, but also cause regular red-shift and blue-shift of the THz absorption peaks of triacontanoic acid, as compared with those of triacontanol. In addition, density functional theory (DFT) B3LYP/6-311G(d,p) basis set was employed to simulate the THz spectra of saturated straight-chain alkane, alkanol and acid, respectively. The simulation results indicate that for the organic molecules with stronger intermolecular H bonds, lower consistent degree of the THz spectrum simulated from monomer molecule with the THz spectrum experimentally measured will occur. Moreover, the simulation results of dimer structures agree well with the measured spectra as compared to those simulated from monomer molecule structures. The results presented in this work are of great significance not only to the study of the THz spectral characteristics of other organic functional groups, but also to the clarification of the vibration modes of organic molecules. Particularly, our results are also helpful for clarifying the THz response theory of organics, and for exploiting the applications of organic materials in THz devices.

Objective: To investigate the existing different gene sequences of hepatitis E virus (HEV) in the southern areas of China., Methods: Eight acute-phase sera of sporadic patients with hepatitis E in Xiamen were tested by reverse transcription--polymerase chain reaction(RT-PCR). Two cases of them were positive. The fifth passage culture of Guangzhou G93-2 strain of HEV was also detected by RT-PCR. The positive RT-PCR products underwent cloning and nucleotide sequencing., Results: The homology of nucleotide and the amino acid between Xiamen X-S1 and Guangzhou G93-2 strain are 99.2% and 97.5%. The homology of nucleotide and the amino acid sequences of Xiamen strain and Guangzhou strain are 79.9% and 86.3% compared with the Burmese strain (Bur-121) and our country Xinjiang strain (87A), and are 77.4% and 86.3% against Mexican strain., Conclusion: The results suggest that there is a different genotype of HEV in the southern areas of China.