Analytical results for the superflow of spin-orbit-coupled Bose-Einstein condensates in optical lattices

In this paper, we show that for sufficiently strong atomic interactions, there exist analytical solutions of current-carrying nonlinear Bloch states at the Brillouin zone edge to the model of spin-orbit-coupled Bose-Einstein condensates (BECs) with symmetric spin interaction loaded into optical lattices. These simple but generic exact solutions provide an analytical demonstration of some intriguing properties which have neither an analog in the regular BEC lattice systems nor in the uniform spin-orbit-coupled BEC systems. It is an analytical example for understanding the superfluid and other related properties of the spin-orbit-coupled BEC lattice systems.Comment: 9 pages, 6 figure

Parameter Matching Method of a Battery-Supercapacitor Hybrid Energy Storage System for Electric Vehicles

To satisfy the high-rate power demand fluctuations in the complicated driving cycle, electric vehicle (EV) energy storage systems should have both high power density and high energy density. In order to obtain better energy and power performances, a combination of battery and supercapacitor are utilized in this work to form a semi-active hybrid energy storage system (HESS). A parameter matching method of battery-supercapacitor HESS for electric vehicles (EVs) is proposed. This method can meet the performance indicators of EVs in terms of power and energy for parameter matching. The result shows that optimized parameter matching is obtained by reducing the weight and cost

Characterization of the mitochondrial genome of parupeneus indicus (perciformes, mullidae)

Parupeneus indicus, a species in the family Mullidae, inhabits the coastal and inner lagoon reefs of the Indian and Pacific oceans. The mitochondrial genome of P. indicus is 16,566 base pairs in length and contains 13 protein-coding genes (PCGs), 22 transfer RNA (tRNA) genes, two ribosomal RNA (rRNA) genes, and a D-loop control region. The overall base composition is 26.58% A, 24.83% T, 30.39% C, and 18.19% G, indicating an AT-rich profile (51.41%). Phylogenetic analysis based on the 13 PCGs revealed a close evolutionary relationship between P. indicus and P. barberinus. The data obtained in this study represent a valuable mitogenomic resource for population studies in the family Mullidae and will contribute to gaining a better understanding of the conservation genetics and environmental DNA of these fish

Experimental Study on Drop-Weight Impact Response of Basalt Fiber Aluminum Laminates (BFMLs)

The basalt fiber-reinforced polymer (epoxy resin), which has even better mechanical properties than glass fiber-reinforced polymer, is a good choice for making FML (fiber-metal laminate) composite. Herein, drop-weight impact tests of basalt fiber-based FMLs (called BFMLs) were conducted in the INSTON 9520HV testing machine to investigate the low-velocity impact properties of BFMLs. The specimens were of two diameters. And the impactors had two sizes of nose, dropping from different heights. The load-deflection behavior of aluminum sheet, BFRP (basalt fiber-reinforced polymer) panel, and BFML plate and their energy dissipation patterns during impact perforation were obtained. The test results showed that aluminum alloy sheet and BFMLs had no strain rate effect, while BFRP did. It was also concluded that the behavior of the thick BFML plate was clearly affected by debonding between aluminum sheet and BFRP panel, while the behavior of the thin BFML plate was controlled by membrane force. In failure analysis, it was found that the deformation and breakage of BFRP are the main contributions to energy absorption of BFMLs which counts for more than 75%. The energy absorbed by the aluminum sheet through plastic deformation and petaling is about 20%, while the energy absorbed in debonding can be ignored. In addition, with the help of ABAQUS simulation, it was found that decreasing the value of MVF (metal volume fraction) can increase the specific energy absorption of BFMLs, but the ductility of BFMLs may decrease

Characterization of the complete mitochondrial genome of the coral reef fish, Hemigymnus melapterus (Pisces: Labridae) and its phylogenetic implications

Hemigymnus melapterus belongs to the family Labridae, which inhabit in coastal and continental shelf waters. The entire mitochondrial genome of H. melapterus is 16,527 base pairs (bp) in length and contained 13 protein-coding genes, two rRNA genes, and 22 tRNA genes. The overall base composition is 27.56% A, 25.58% T, 30.02% C, and 16.85% G, showing AT-rich feature (53.14%). Phylogenetic analysis based on 13 protein-coding genes shows the H. melapterus has the closest evolutionary relationship with Stethojulis strigiventer. This work provides valuable genome variation information, which will be useful for phylogenetic analysis and population genetics research

A new record of Upeneus pori (Actinopterygii: Syngnathiformes: Mullidae) from the South China Sea: Integrating morphology and DNA barcoding

This study constitutes the first record of the Por’s goatfish, Upeneus pori Ben-Tuvia et Golani, 1989, from the South China Sea. This fish had formerly only been reported in the western Indian Ocean. Six specimens of U. pori collected from the South China Sea were identified through comparisons of morphology and molecular analysis. Upeneus pori and Upeneus tragula Richardson, 1846 are very similar. The difference is that the former has seven spines in the first dorsal fin, lacks any spots or blotches on its body, and exhibits white or creamy white barbels. The latter has eight spines in the first dorsal fin, exhibits black spots on its body, and displays orange-colored barbels, along with different caudal fin patterns. Pairwise genetic distance computation demonstrated that U. pori exhibits a very low genetic distance from sequences of the other three recorded U. pori species found in the type locality of Israel, Red Sea, as documented in GenBank. These findings provide compelling evidence of the Por’s goatfish’s presence in the South China Sea

Physics of manipulation of spin dynamics in a driven double well made transparent

We study the coherent manipulation of quantum spin dynamics via simple analytic solutions for a spin–orbit (SO) coupled ultracold atom held in a driven double well. In the high-frequency regime, we analytically obtain the quasienergies, the Floquet states, and the non-Floquet state of this system. When the system parameters are properly selected, the non-Floquet state reduces to special quantum states of simple forms which can provide a more intuitive understanding of some interesting quantum spin dynamical phenomena, such as the intrawell spin–flipping, the interwell spin-conserving tunneling, and the interwell spin–flipping tunneling. Specially, for the interwell spin–flipping tunneling, we surprisingly find that the selective coherent destruction of tunneling (SCDT) can occur at the anti-crossing (non-collapse) points of quasienergy spectrum, which breaks the conventional understanding that the SCDT is associated with the crossing of quasienergy levels. Further, we reveal the interwell spin–flipping tunneling strongly depends on the initial spin direction and the initial position of the SO-coupled atom. These novel results can be readily tested by the current experimental setups and may be useful for the design of spintronic devices

Feeding Ecology of Nemipterus japonicus in Beibu Gulf

The Beibu Gulf is the fourth largest Chinese fishing ground, with rich fishery resources and a significant role in marine fishery production. The feeding ecology of fish is important to explain the structure and function of marine ecosystems. As one of the most important fish species in the Beibu Gulf, Nemipterus japonicus plays an essential role in energy flow and other aspects of the marine ecosystem. Understanding its feeding ecology could provide a basic theoretical basis for the rational utilization and protection of this resource. A total of 248 N. japonicus specimens were collected from Beibu Gulf from January to April and August to December in 2018. The food content composition, feeding intensity, and feeding niche of N. japonicus were analyzed using stomach contents to reflect feeding habits. Combined with carbon and nitrogen stable isotopes, the food source and trophic structure characteristics were analyzed, the trophic level was determined, and the feeding ecology of N. japonicus in the Beibu Gulf was discussed. The stomach content analysis revealed that N. japonicus is a broad-feeding benthic carnivore, which feeds on a large number of species, including eight prey groups, including fish, shrimp, and crab, among which fish and shrimp are the dominant food groups, with a relative importance index of 92.92%. The proportion of food species varied with the season and growth. Fish were an important prey group across all seasons. Moreover, N. japonicus preyed on shrimp in spring, crab in summer, shrimp and polychaetes in autumn, and shrimp and sipunculoidea in winter. With an increase in body length, the feeding habits of N. japonicus gradually change from primarily feeding on shrimp and fish to mainly feeding on fish, and the body length node of feeding transition was approximately 130 mm. There were clear seasonal variations in feeding intensity, with the highest intensity in autumn, followed by that in spring and summer, and the lowest in winter. N. japonicus had a high prey diversity; the Shannon-Wiener diversity index (H') was 1.77, and the Pielou evenness index (J') was 0.64. From spring to winter, the H' and J' values tended to increase and then decrease, and the highest value occurred in autumn, which meant that the feeding niche was the highest in autumn. The number of prey species increased with individual growth, and H' and J' showed an increasing trend with body length. The group with a body length ≥ 160 mm had the largest niche width, which suggested that the food diversity increased with individual growth, and the diet changed to broad-feeding.Based on stable isotope analysis, δ13C was positively correlated with the body length of N. japonicus (P < 0.05), indicating that the trophic source changed with growth. The span of the δ13C (CR) range was 2.86%, indicating extensive basic food sources. The span of the δ15N (NR) range was 4.23%, and the trophic span was more than one trophic level, indicating considerable differences in feeding among individuals. A significant positive correlation was found between body length and δ15N (P < 0.01), which indicated that the trophic level increased with an increasing body length. The trophic level of N. japonicus ranged from 3.21 to 4.46, with an average value of 3.97, indicating that N. japonicus species were middle-high carnivorous animals, and were at a high trophic level in the fish food web of the Beibu Gulf. The trophic level obtained in this study is higher than that obtained in other studies, which may be related to the changes in the composition of the prey, N. japonicus has shifted from feeding mainly on the low trophic level (crustaceans) to the high trophic levels (fish).In terms of trophic structure, the CR value of N. japonicus in the Beibu Gulf in spring and winter was lower than that in summer and autumn, indicating that the basic food source diversity in spring and winter is lower than that in summer and autumn, however, there are fewer prey species in summer, which might be caused by the feeding preference of N. japonicus. Simultaneously, the NR values in spring and summer were greater than those in summer and autumn, indicating that the span of the main trophic sources in the feed was higher than that in summer and autumn, consistent with the seasonal variation of dominant prey. Although the standard ellipse area (SEA) overlaps to different degrees among seasons, the total niche (TA) had clear seasonal differences, signifying that there were certain similarities and specific differences in prey resource utilization, which is beneficial for alleviating the seasonal pressure on the dominant prey. Furthermore, the CR value in different body length groups of N. japonicus showed an overall upward trend with individual growth, indicating that the food source diversity increased with growth. The NR value decreased when body length was greater than 130 mm, which indicates that the average trophic level of the population was concentrated when individuals grew to a certain stage. The SEA overlap rate was higher among length groups, implying that the trophic source components were similar at different growth stages; however, TA tended to increase and then decrease with body length, which may reduce food competition within species by niche differentiation