Terahertz time-domain spectroscopy has been used to measure the characteristic spectra of the similarly structured mono-saccharides D-glucose and D-galactose in the polycrystalline state at room temperature. A number of wellresolved absorption peaks were observed in the frequency range 0.2-3.0THz, which are interpreted as originating from inter-and intra-molecular vibrational modes. In parallel with the experimental study, density functional theory (DFT) was first applied to obtain structure and vibrational frequencies of the isolated galactose molecule in terahertz region. The calculated results are fitted reasonable with the experimental data. Observed vibrational frequencies have been interpreted using DFT. The comparison between experimental and theoretical study shows that far-infrared absorption features are highly sensitive to the structure and spatial arrangement of the molecules. This work also demonstrated that THz-TDS is a potentially important tool in understanding the collective vibrational modes and conformational structures of molecules.
This paper describes hybrid-redundant design of monitoring systems with proprietary industrial-control computer boards. Input channels use three-mode redundancy, host controllers two-mode redundancy and output channels use warm redundancy. Experiments and analysis of system reliability by the Markov model indicate that the reliability of normal operation for 5 years is above 0.9.
This paper describes a system comprising two heaters closely located, whose characteristics such as temperature-coupling and long adjustment time cause unsatisfactory performance when using conventional control methods. A modeling and control method has been developed for this system, that is: a decoupling compensator is designed to diagonalize the transfer function matrix of the controlled object so that each controller only acts on the relative controlled object, and the interaction between the circuits is eliminated as a result. Some recursive difference equation algorithms are introduced based on the PID concept, as well as a decoupling compensation algorithm and a twin-screw extruder heater model. Research results show that the temperature adjustment time is decreased from 17 minutes to 8 minutes using this new method. Overshoot is also reduced from 15% to 7%, while steady-state error from 2ºC to 1ºC, all of which are significant improvements over previous methods.
scite is a Brooklyn-based organization that helps researchers better discover and understand research articles through Smart Citations–citations that display the context of the citation and describe whether the article provides supporting or contrasting evidence. scite is used by students and researchers from around the world and is funded in part by the National Science Foundation and the National Institute on Drug Abuse of the National Institutes of Health.