Search

Saponins are the main active components in Panax ginseng C. A. Mey. (PG), Panax quinquefolius L. (PQ), and Panax japonicus C. A. Mey. (PJ), which belong to the genus Panax in the Araliaceae family. Because the chemical components in the three species are similar, they are often mixed and misused in functional foods and pharmaceuticals applications. Therefore, it is urgent to establish a method to quickly distinguish among PG, PQ, and PJ. Ultraperformance liquid chromatography quadrupole time-of-flight mass spectrometry (UPLC-Q-TOF/MS) was combined with data postprocessing to identify the main characteristic fragments (CFs) and the related neutral losses (NLs) of protopanaxadiol (PPD), protopanaxatriol (PPT), oleanolic acid (OLE), and ocotillol- (OCO-) type saponins. By comparing the mass spectral data, it was possible to rapidly classify and identify saponins in PG, PQ, and PJ. A total of twenty-three chemical components were identified in the PG samples, twenty-three components were identified in the PQ samples, and twenty-seven components were identified in the PJ samples. Among them, OCO-type saponins were characteristic of PQ and PJ. Ginsenoside Rf, which was absent from PQ, allowed for differentiation between PQ and PJ. The CFs and NLs in the mass spectra of the characteristic components of PG, PQ, and PJ allowed for the rapid classification and identification of these species. Additionally, these results provide technical support for the quality evaluation of Chinese herbal medicine and for constructing a scientific regulatory system.

This study investigated how enhanced video captioning types affected comprehension and vocabulary acquisition regarding form recognition, meaning recall and meaning recognition. 158 low-intermediate Chinese EFL undergraduates were randomly assigned to English captions (EC), English captions with highlighted target words and L1 gloss (ECL1), Chinese and English captions (CEC), Chinese and English captions with highlighted target words (CECGW), and no captions (NC). For listening comprehension, results revealed the CECGW scored higher than CEC, EC and NC while the NC performed lower than other groups with statistical significance. Captioned videos and videos bilingually captioned with glossed target words aided listening comprehension. For form recognition in vocabulary tests, no statistically significant differences were detected across the caption types. ECL1 was the most effective in meaning recall and recognition. Pedagogical implications are proposed for teachers' adoption of L1 in captioned videos for learners' optimal learning.

Numerical analysis of the sediment erosion of the balance valve in a buoyancy regulation system was performed. A numerical model for the two-phase flow inside the balance valve was constructed based on the discrete phase model. The sediment erosion rate on the balance valve was discussed, and the effects of five parameters were considered. The effects of the sediment concentration and valve opening were found to be significant, while the effects of the pressure difference, sediment density, and size were found to be moderate. The erosion rate, according to the numerical results, increased linearly with the sediment concentration, so long-term operation of a buoyancy regulation system in high-concentration areas should be avoided. The erosion rate was the highest when the valve opening was 46.3%, so half-open operating conditions are not recommended. The erosion rate was proportional to the square root of the pressure difference. However, adjusting the pressure difference may not be an effective method for regulating the total erosion. The superposition of the secondary flow and the main stream caused particles to spiral along with the fluid, resulting in asymmetric erosion at the working edge. The erosion rate on the working edge decreased with the increase in the sediment size. Conversely, the erosion rate on the valve ball surface increased with the sixth power of the sediment size. Considering that large particles are more likely to cause a blockage, it is recommended to install a seawater pretreatment device at the inlet to prevent large sediments from entering the valve and to improve the working life of the buoyancy regulation system. [ABSTRACT FROM AUTHOR]

Molybdenum disulfide (MoS2) is a promising anode material for lithium-ion batteries (LIBs) due to its distinctive graphene-like structure and high specific capacity. However, its commercial application is hindered by the severe volume expansion during lithiation/delithiation and poor conductivity. In this paper, we report a facile one-pot enhanced hydrothermal synthesis strategy to prepare high-performance MoS2/C composite materials. The results indicate that the as-prepared MoS2/C composite is a subspheroidal core–shell structure material, with uniform coating, good particle dispersion, and an average grain size of approximately 80 nm. The morphology of the composite remained unchanged even after annealing at 500 °C for 2 h. The addition of glucose can accelerate the nucleation and growth of MoS2, and higher hydrothermal temperatures can improve the product yield. The addition of PVP has little effect on the yield, but significantly reduces the particle size. The XPS analysis reveals that the MoO3 may be generated as an intermediate product during the hydrothermal process. The electrochemical test results show that the unannealed MoS2/C samples exhibit discharge-specific capacities of 705.2 mAh·g−1 and 625.7 mAh·g−1 after the first cycle and the 100th cycle, respectively, at a current density of 500 mA·g−1, with a capacity retention rate of 88.7%. In contrast, the specific capacity of the MoS2/C specimens after annealing at 500 °C for 2 h shows a tendency to decrease and then slowly increase during the cycles, and the discharge specific capacity is 582.3 mAh·g−1 after the 100th cycle, which is lower than that of the unheated sample. The impedance analysis reveals that the lithium-ion diffusion coefficient of the MoS2/C material without calcination is 2.11 × 10−18 cm·s−2, which is superior to that of the annealed MoS2/C and pristine MoS2 samples. This characteristic is favorable for lithiation/delithiation during the charge/discharge process. [ABSTRACT FROM AUTHOR]

We propose a multidimensional reconciliation encoding algorithm based on a field-programmable gate array (FPGA) with variable data throughput that enables quantum key distribution (QKD) systems to be adapted to different throughput requirements. Using the circulatory structure, data flow in the most complex pipeline operation in the same time interval, which enables the structural multiplexing of the algorithm. We handle the calculation and storage of eight-dimensional matrices cleverly to conserve resources and increase data processing speed. In order to obtain the syndrome more efficiently, we designed a simplified algorithm according to the characteristics of the FPGA and parity-check matrix, which omits the unnecessary operation of matrix multiplication. The simplified algorithm could adapt to different rates. We validated the feasibility and high speed of the algorithm by implementing the multidimensional reconciliation encoding algorithm on a Xilinx Virtex-7 FPGA. Our simulation results show that the maximum throughput could reach 4.88 M symbols/s. [ABSTRACT FROM AUTHOR]