RESUMO
Sweet potato virus disease (SPVD) is one of the main virus diseases in sweet potato [Ipomoea batatas (L.) Lam] that seriously affects the yield of sweet potato. Therefore, the establishment of a simple, rapid and effective method to detect SPVD is of great significance for the early warning and prevention of this disease. In this study, the experiment was carried out in two years to compare the grafting method and side grafting method for three sweet potato varieties, and the optimal grafting method was selected. After grafting with seedlings infected with SPVD, the symptomatic diagnosis and serological detection were performed in 86 host varieties, and the differences in SPVD resistance were determined by fluorescence quantitative PCR (qRT-PCR) and nitrocellulose membrane enzyme-linked immunosorbent assay (NCM-ELISA). The results showed that the survival rate of grafting by insertion method was significantly higher than that by side grafting method, and the disease resistance of different varieties to sweet potato virus disease was tested. The detection method established in this study can provide theoretical basis for identification and screening of resistant sweet potato varieties.
RESUMO
A single-longitudinal-mode narrow-linewidth fiber ring laser with stimulated Brillouin scattering (SBS) assisted parity-time (PT) symmetry for mode selection in a single fiber loop is proposed and experimentally demonstrated. When an optical pump is launched into the fiber loop along one direction, an SBS gain for the Stokes light along the opposite direction is produced. For two light waves at the Stokes frequency propagating along the two opposite directions, one will have a net gain and the other will have a net loss. By incorporating a fiber Bragg grating (FBG) with partial reflection in the loop, mutual coupling between the two counterpropagating Stokes light waves is achieved. The SBS gain can be controlled by tuning the angle between the polarization directions of the pump and the Stokes light waves through a polarization controller (PC). Once the gain and loss coefficients between the two counterpropagating light waves are controlled to be identical in magnitude, and that the gain coefficient is greater than the coupling coefficient caused by the FBG, PT symmetry breaking is achieved, making the mainmode to sidemode ratio highly enhanced, single mode lasing is thus achieved. The approach is evaluated experimentally. For a fiber ring laser with a cavity length of 8.02 km, single-mode lasing with a narrow 3-dB linewidth of 368 Hz and a sidemode suppression ratio of around 33 dB is demonstrated. The wavelength tunable range from 1550.02 to 1550.18 nm is also demonstrated.
RESUMO
In this study, a natural rubber (NR) based amphiphilic semi-interpenetrating polymer network (semi-IPN) superabsorbent hydrogel was designed and synthesized with natural rubber-graft-poly (acrylic acid-co-acrylamide) [NR-g-P(AA-co-AM)] network and linear poly (diallyldimethyl ammonium chloride) (PDADMAC). Through a series of characterization and test, the structure, morphology, thermal properties, biodegradation, and swelling properties of NR-g-P(AA-co-AM)/PDADMAC were determined. Subsequently, NR-g-P(AA-co-AM)/PDADMAC was used for ammonium adsorption to remove ammonium nitrogen in aqueous solution. The adsorption behavior of the absorbent was also studied. Results showed that the maximum water absorbency of NR-g-P(AA-co-AM)/PDADMAC was 112.04 ± 6.55 g/g and water retention capacity of soil with the superabsorbent was 115.62 ± 2.08%. The NH4+ adsorption quickly reached equilibrium and the maximum adsorption capacity was 13.02 mmol g-1 calculated from Langmuir isotherm model. The results suggest that the product is efficient for ammonium removal and can be used as water-retaining agents.
