RESUMO
We propose a scheme for realizing nonreciprocal microwave photon routing with two cascaded magnon-cavity coupled systems, which work around the exceptional points of a parity-time (PT)-symmetric Hamiltonian. An almost perfect nonreciprocal transmission can be achieved with a broad bandwidth, where the transmission for a forward-propagating photon can be flexibly controlled with the backpropagating photon being isolated. The transmission or isolated direction can be reversed via simply controlling the magnetic field direction applied to the magnons. The isolation bandwidth is improved by almost three times in comparison with the device based on a single PT-symmetric system. Moreover, the effect of intrinsic cavity loss and added thermal noises is considered, confirming the experimental feasibility of the nonreciprocal device and potential applications in quantum information processing.
RESUMO
A previously unknown, water-soluble polysaccharide, named DOTP-B, was isolated from the roots of the plant Dioscorea opposita Thunb, a well-known edible and medicinal plant in China. DOTP-B was found to be neutral in charge, with an average molecular weight of 5623â¯Da. Monosaccharide composition analysis by GC-MS revealed that DOTP-B was a hetero-polysaccharide consisting of glucose and galactose at a molar ratio of 14.6:1.0. Structural features of DOTP-B were investigated with a combination of chemical and instrumental methods, including complete acid hydrolysis, periodate oxidation, methylation, GC-MS, FTIR and several NMR spectra. Highly correlated results demonstrated that the main chain of DOTP-B consisted of â4)-α-d-glc(1â¯ââ¯residues, with about 6% internal â6)-ß-d-gal(1â¯ââ¯residues. The antioxidant activity of DOTP-B was also evaluated as the EC50 values against DPPH and PTIO radicals were 2.1⯱â¯0.1â¯mg/mL and 1.6⯱â¯0.1â¯mg/mL, respectively. Therefore, the polysaccharide DOTP-B could be possibly developed as a promising natural antioxidant for application in medical and food industries.
