Digital economy, green technology innovation, and productivity improvement of energy enterprises.

This study aims to address the important question of whether the digital economy can be deeply integrated with the energy sector to break through the resource and environmental constraints and thus enhance the productivity of energy companies. Using a sample of Chinese energy-listed companies, we comprehensively investigate the impact of the digital economy on the productivity of energy firms using the OLS method, mediated effects model, instrumental variables method, and difference-in-differences model. Research shows that the development of digital economy can significantly improve the productivity of energy enterprises. This effect is more obvious in eastern cities, non-resource-based cities, state-owned enterprises, and enterprises with high cash holdings. Green technological innovation in alternative energy production, transportation, and administrative supervision and design is an important channel for improving productivity in the digital economy. Internet development and digital inclusive finance can also improve the productivity of energy enterprises. "National Big Data Pilot Zone" and "Broadband China" pilot cities can play a policy role in improving the productivity of energy enterprises. The findings provide important insights for promoting the integration of the digital revolution with the energy technology revolution and accelerating the green development and digital transformation of the energy sector.

Quantification of Photosynthetic Pigments in Neopyropia yezoensis Using Hyperspectral Imagery.

Phycobilisomes and chlorophyll-a (Chla) play important roles in the photosynthetic physiology of red macroalgae and serve as the primary light-harvesting antennae and reaction center for photosystem II. Neopyropia is an economically important red macroalga widely cultivated in East Asian countries. The contents and ratios of 3 main phycobiliproteins and Chla are visible traits to evaluate its commercial quality. The traditional analytical methods used for measuring these components have several limitations. Therefore, a high-throughput, nondestructive, optical method based on hyperspectral imaging technology was developed for phenotyping the pigments phycoerythrin (PE), phycocyanin (PC), allophycocyanin (APC), and Chla in Neopyropia thalli in this study. The average spectra from the region of interest were collected at wavelengths ranging from 400 to 1000 nm using a hyperspectral camera. Following different preprocessing methods, 2 machine learning methods, partial least squares regression (PLSR) and support vector machine regression (SVR), were performed to establish the best prediction models for PE, PC, APC, and Chla contents. The prediction results showed that the PLSR model performed the best for PE (R Test 2 = 0.96, MAPE = 8.31%, RPD = 5.21) and the SVR model performed the best for PC (R Test 2 = 0.94, MAPE = 7.18%, RPD = 4.16) and APC (R Test 2 = 0.84, MAPE = 18.25%, RPD = 2.53). Two models (PLSR and SVR) performed almost the same for Chla (PLSR: R Test 2 = 0.92, MAPE = 12.77%, RPD = 3.61; SVR: R Test 2 = 0.93, MAPE = 13.51%, RPD =3.60). Further validation of the optimal models was performed using field-collected samples, and the result demonstrated satisfactory robustness and accuracy. The distribution of PE, PC, APC, and Chla contents within a thallus was visualized according to the optimal prediction models. The results showed that hyperspectral imaging technology was effective for fast, accurate, and noninvasive phenotyping of the PE, PC, APC, and Chla contents of Neopyropia in situ. This could benefit the efficiency of macroalgae breeding, phenomics research, and other related applications.

Loss calculation and thermal analysis of ultra-high speed permanent magnet motor.

The ultra-high speed permanent magnet motor (UHSPM) for hydrogen fuel cell air compressor is characterized by high speed, high motor power density, small size, and high reliability. Compared to the conventional motor, the loss per unit volume is increased and therefore the calculation of the temperature field is more important than that of conventional motors. In this paper, a UHSPM with a rated speed of 90000 r/min is designed. Firstly, a finite element (FE) model of the UHSPM is established and the losses of each part of the high-speed motor are calculated, and the calculated losses are introduced into the fluid field in the form of a heat source for motor temperature analysis. The calculated losses were introduced into the fluid field in the form of a heat source and used in the motor temperature analysis. The temperature rise was then calculated for the unidirectional and bidirectional magneto-thermal coupling (MTC) respectively. The results show that the bidirectional magneto- thermal coupling (BMTC) simulation results are about 2-3 °C smaller than the experimental measured values, which can more accurately predict the motor temperature. The measurement results verify the accuracy of BMTC, and provide basic theoretical support for the subsequent cooling optimization scheme of high-speed motor.

Digital economy development and haze pollution: evidence from China.

The development of the digital economy radiates to national ecological protection and resource utilization, holding the key to haze governance. However, as the largest developing country, the impact of China's digital economy on haze pollution has received little attention. Based on the panel data of 275 prefecture-level cities in China from 2011 to 2018, this paper studies the impact and mechanism of digital economy development on haze pollution. The results of fixed effect model show that the development of digital economy has a significant negative impact on urban haze pollution in China. The results of heterogeneity analysis show that the development of digital economy has a more significant inhibitory effect on the haze pollution of resource-based cities, non-resource-based cities, eastern cities, and large cities. The quasi-natural experimental results show that the establishment of the "national big data comprehensive experimental area" is conducive to haze pollution control, which proves the conclusion that the digital economy can significantly reduce haze pollution. The development of digital economy can significantly reduce haze pollution by promoting technological innovation and optimizing resource allocation.

Adsorption behavior and mechanism of Lead (Pb2+) by sulfate polysaccharide from Enteromorpha prolifera.

Lead (Pb2+) pollution poses severe healthy and ecological risks to humans. In this work, sulfate polysaccharide from Enteromorpha prolifera (SPE) was utilized for Pb2+ adsorption from simulated intestinal fluid. In order to evaluate its adsorption behaviors comprehensively, batch adsorption of Pb2+ was investigated under different conditions. Results showed that SPE presents high adsorption ability for Pb2+ through chemical adsorption process and the maximum adsorption capacity for Pb2+ was 278.5 mg/g. And SPE exhibited higher removal efficiency (≥60%) for trace Pb2+ (<10 mg/L) compared to that of other adsorbents based on polysaccharide. Besides, its adsorption can be described by Langmuir isotherm and pseudo-second-order kinetic models. Further, XRD, FTIR, and XPS were used to characterize the possible interaction of Pb2+ with SPE, and the results showed that carboxyl and hydroxyl groups in SPE play more important role than that of sulfate group. Our work represents the first assessment of Pb2+ adsorption properties of SPE. This investigation highlights the potential application of SPE to protect the body from hazard of food-derived heavy metals.

Discrepancy in photosynthetic responses of the red alga Pyropia yezoensis to dehydration stresses under exposure to desiccation, high salinity, and high mannitol concentration.

Macroalgae that inhabit intertidal zones are exposed to the air for several hours during low tide and must endure desiccation and high variations in temperature, light intensity, and salinity. Pyropia yezoensis (Rhodophyta, Bangiales), a typical intertidal red macroalga that is commercially cultivated in the northwestern Pacific Ocean, was investigated under different dehydration stresses of desiccation, high salinity, and high mannitol concentration. Using chlorophyll fluorescence imaging, photosynthetic activities of P. yezoensis thalli were analyzed using six parameters derived from quenching curves and rapid light curves. A distinct discrepancy was revealed in photosynthetic responses to different dehydration stresses. Dehydration caused by exposure to air resulted in rapid decreases in photosynthetic activities, which were always lower than two other stresses at the same water loss (WL) level. High salinity only reduced photosynthesis significantly at its maximum WL of 40% but maintained a relatively stable maximum quantum yield of photosystem II (PSII) (Fv/Fm). High mannitol concentration induced maximum WL of 20% for a longer time (60 min) than the other two treatments and caused no adverse influences on the six parameters at different WL except for a significant decrease in non-photochemical quenching (NPQ) at 20% WL. Illustrated by chlorophyll fluorescence images, severe spatial heterogeneities were induced by desiccation with lower values in the upper parts than the middle or basal parts of the thalli. The NPQ and rETRmax (maximum relative electron transport rate) demonstrated clear distinctions for evaluating photosynthetic responses, indicating their sensitivity and applicability. The findings of this study indicated that the natural dehydration of exposure to air results in stronger and more heterogeneous effects than those of high salinity or high mannitol concentration.

Diuron effects on photosynthesis and vertical migration of microphytobenthos: Potential rapid bioassessment of herbicide toxicity in coastal sediments.

The effects of herbicide diuron on photosynthesis and vertical migration of intertidal microphytobenthos (MPB) assemblages were investigated using chlorophyll fluorometry. The results shown diuron ≤ 60 µg L-1 had no obvious effect on MPB vertical migration during 24 h indicated by consistent rhythm. Low concentration of 10 µg L-1 diuron had no significant influence on MPB photosynthesis throughout, however, high concentrations of 40, 50, and 60 µg L-1 had significant impacts exhibited by decreased parameters of maximum relative electron transport rate (rETRmax), maximal PS II quantum yield (Fv/Fm) and non-photochemical quenching (NPQ). For middle concentrations of 20 and 30 µg L-1, above decreased 3 parameters recovered sooner or later after 2 h or 16.5 h. Comparatively, rETRmax, Fv/Fm and NPQ are concentration dependent and more sensitive than other parameters in assessing diuron toxicity. This study revealed the potential of using MPB assemblages and chlorophyll fluorometry for rapid assessing diuron toxicity in coastal sediments.

Biomass estimation of cultivated red algae Pyropia using unmanned aerial platform based multispectral imaging.

BACKGROUND: Pyropia is an economically advantageous genus of red macroalgae, which has been cultivated in the coastal areas of East Asia for over 300 years. Realizing estimation of macroalgae biomass in a high-throughput way would great benefit their cultivation management and research on breeding and phenomics. However, the conventional method is labour-intensive, time-consuming, manually destructive, and prone to human error. Nowadays, high-throughput phenotyping using unmanned aerial vehicle (UAV)-based spectral imaging is widely used for terrestrial crops, grassland, and forest, but no such application in marine aquaculture has been reported. RESULTS: In this study, multispectral images of cultivated Pyropia yezoensis were taken using a UAV system in the north of Haizhou Bay in the midwestern coast of Yellow Sea. The exposure period of P. yezoensis was utilized to prevent the significant shielding effect of seawater on the reflectance spectrum. The vegetation indices of normalized difference vegetation index (NDVI), ratio vegetation index (RVI), difference vegetation index (DVI) and normalized difference of red edge (NDRE) were derived and indicated no significant difference between the time that P. yezoensis was completely exposed to the air and 1 h later. The regression models of the vegetation indices and P. yezoensis biomass per unit area were established and validated. The quadratic model of DVI (Biomass = - 5.550DVI2 + 105.410DVI + 7.530) showed more accuracy than the other index or indices combination, with the highest coefficient of determination (R2), root mean square error (RMSE), and relative estimated accuracy (Ac) values of 0.925, 8.06, and 74.93%, respectively. The regression model was further validated by consistently predicting the biomass with a high R2 value of 0.918, RMSE of 8.80, and Ac of 82.25%. CONCLUSIONS: This study suggests that the biomass of Pyropia can be effectively estimated using UAV-based spectral imaging with high accuracy and consistency. It also implied that multispectral aerial imaging is potential to assist digital management and phenomics research on cultivated macroalgae in a high-throughput way.

Analysis of Preload of Three-Stator Ultrasonic Motor.

The pre-pressure device of the ultrasonic motor plays a vital role in the design of the entire motor structure, the contact state of the stator and rotor of the motor, dynamic properties of the stator, friction and wear characteristics of the rotor; even the mechanical behaviors of the entire electric machinery have a profound impact. Appropriate pre-pressure is conducive to the smooth operation of the ultrasonic motor, so that the output performance remains excellent, reducing wear and effectively extend the service life of the motor. Therefore, the research on pre-stress is of great significance, as it can better optimize the structure of the three-stator ultrasonic motor and lay the foundation for the stable operation of the motor. First, this paper introduces the construction of the motor as a whole and the pre-pressure device briefly described the working mechanism of the motor, and then introduces the influence of the pre-pressure on the stator and rotor contact models, the position of the constant velocity point, and the modal frequency. Finally, the motor output under different pre-pressures is discussed. The performance experiment has determined the optimal pre-pressure interval, which provides help for its subsequent optimization.

Effects of three products from Antarctic krill on the nitrogen balance, growth, and antioxidation status of rats.

A few studies conducted over the past few decades have demonstrated the health benefits of a diet rich in marine products, but limited studies have investigated the effects of different krill products on the nitrogen balance and their potential health benefits. In our study, after a 14-day acclimation period, 50 female Sprague-Dawley rats were randomly assigned to five groups, each of which was fed a different diet, for 28 days. We then evaluated the effect of krill protein complex (KPC), krill powder, and defatted krill powder on the nitrogen balance, growth, and antioxidant activity through analyses of MDA, CAT, GSH-Px, and T-SOD. An in vivo analysis suggested that the nitrogen retention rate, protein digestibility, and bioutilization of krill products were equal to those of casein. Moreover, the KPC diet resulted in the highest nitrogen intake and retention among the groups, and the biological value and net protein utilization obtained with KPC were higher than those obtained with defatted krill powder, which was consistent with the weight gains observed for these two groups. The hematological test also showed that KPC contributed to the production of functional proteins in the body. The antioxidant activity analysis indicated that higher GSH-Px and T-SOD activities were obtained with krill products and KPC, respectively, compared with casein. The results from this study suggested that krill proteins could promote growth and improve the antioxidant status of an organism. Although further studies on the safety of krill products for human consumption are needed, this work provides insights into the use of krill proteins as a potential substitute for other proteins and restructured foods.

Evaluating the efficacy of a ferrous-ion-chelating peptide from Alaska pollock frame for the improvement of iron nutritional status in rats.

This study aimed to investigate the effects of ferrous-ion-chelating peptides from Alaska pollock frames (APFP-Fe) on iron deficiency in anaemic rats. We hydrolysed the Alaska pollock frames to obtain a peptide with an average molecular weight of 822 Da. The bioavailability of APFP-Fe was tested using animal experiments. Wistar rats were randomly divided into six groups: an iron deficiency control group, a normal control group, and iron deficiency groups treated with ferrous sulfate (FeSO4) or low-, medium-, or high-dose APFP-Fe. Rats in the iron deficiency groups were fed an iron-deficient diet to establish the iron deficiency anaemia (IDA) model. After the model was established, different iron supplements were given to rats once per day via intragastric administration for 21 days. The results showed that APFP-Fe had restorative effects, returning the body weight, weight gain, height, and haematological parameters in IDA rats to normal levels. In addition, compared with FeSO4, APFP-Fe promoted significant weight gain and effectively improved haemoglobin, serum iron and transferrin levels, and recovery of the capacity of iron binding with transferrin, especially at the medium and high doses. These findings suggest that APFP-Fe is an effective source of iron for improving the iron nutritional status in IDA rats and shows promise as a new source of iron supplementation.

Using one waste to tackle another: preparation of a CO2 capture material zeolite X from laterite residue and bauxite.

In this work, zeolite X, a benchmark adsorbent for carbon capture, has been successfully prepared from low cost waste minerals namely laterite residue and bauxite using alkali fusion process followed by hydrothermal treatment. The structure and morphology of the as-synthesized zeolite X were verified and characterized with a range of experimental techniques such as X-ray diffraction, scanning electronic microscopy and infrared spectroscopy. The surface area and (N2 and CO2) gas adsorption isotherms of this product were found comparable to that of commercial ones, demonstrating the effectiveness of synthesizing zeolite X from laterite and bauxite. Further improvement of the product purity was also accomplished by optimizing the process conditions.

Complete Genome Sequence of Antarctic Bacterium Psychrobacter sp. Strain G.

Here, we report the complete genome sequence of Psychrobacter sp. strain G, isolated from King George Island, Antarctica, which can produce lipolytic enzymes at low temperatures. The genomics information of this strain will facilitate the study of the physiology, cold adaptation properties, and evolution of this genus.

Response of heat-shock protein (HSP) genes to temperature and salinity stress in the antarctic psychrotrophic bacterium Psychrobacter sp. G.

Temperature and salinity fluctuations are two of the most important factors affecting the growth of polar bacteria. In an attempt to better understand the function of heat-shock proteins (HSPs) in the adaptive mechanisms of the Antarctic psychrotrophic bacterium Psychrobacter sp. G to such conditions, genes Hsp845, Hsp2538, Hsp2666, and Hsp2667 were cloned on the basis of the draft genome. The expression characteristics of these HSP genes under different stress conditions were analyzed by the qRT-PCR method. Expression of Hsp845 and Hsp2667 was inhibited significantly by low temperature (0 and 10 °C, respectively). There was no difference of expression when Hsp2538 and Hsp2666 were exposed to 0 °C but the expression of Hsp2666 was inhibited when exposed to 10 °C. Expression of Hsp2538 and Hsp2667 was not sensitive but expression of Hsp845 and Hsp2666 was increased at low salinity (0 and 15, respectively). Expression of the four HSP genes was enhanced at high salinity (90 and 120) and at high temperature independent of salinity. By contrast, low temperature had no significant effect independent of salinity.

Identification of regulatory sequences and expression analysis of OmpR gene under different stress conditions in the antarctic bacterium Psychrobacter sp. G.

An OmpR gene, named OmpR503, was cloned from the Antarctic psychrotrophic bacterium Psychrobacter sp. G according to its genomic draft. The deduced amino acid sequences of OmpR503 were highly conserved with other known protein members of OmpR family. qRT-PCR analysis showed that the expression of OmpR503 gene was significantly enhanced by high salinity (90, 120). The expression of OmpR503 gene was also significantly increased at low temperature (0, 10 °C), whereas depressed at high temperature (30 °C). When the strain was subjected to combined stress (0 °C with a salinity of 90), the expression of OmpR503 gene was increased significantly, which was up to 3.0-fold. In Antarctica, freezing tolerance of psychrotrophic bacteria is often accompanied by tolerance to osmotic stress caused by a lack of free water, thus the cold inducibility of OmpR503 gene might help the strain adapt to the harsh environment more efficiently.