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Abstract Bend pipe is a common part of long distance pipeline. There is very important to study the flow law of hydrate particles in the bend pipe, and pipeline design will be optimized. In addition, the efficiency and safety of pipeline gas transmission will be improved. With the flow of hydrate particles in a curved pipe as the object of study, the effects of Bend diameter rate and Reynolds number on the velocity distribution, turbulent kinetic energy change, wall shear force, particle motion and pressure drop distribution of the spiral flow carrying hydrate particles were investigated by numerical simulation method. The results show that bend diameter rate is the smaller, and the high speed zone is easier to appear inside the bend. Moreover, the uniformity of the velocity distribution of the fluid flowing through the bend is slower with the smaller the rate of the bend to the diameter. When Re = 20,000, the curve fluctuates more, and the peak speed reaches 4 times that of Re = 10,000. Increasing the Reynolds number of the initial transport can maintain the helical flow strength of the fluid after passing through the bend pipe, so that the flow can obtain higher tangential force. Because the fluid flows into the pipe by spiral flow, the shear force inside the pipe is higher under the combined action of its tangential velocity at the pipe wall and the high speed zone inside the pipe wall. The presence of the twisted tape leads to greater flow resistance, which makes the pressure drop increase at the position of the twisted tape different. At the same position, the Reynolds number is larger, and the pressure drop increases larger, and the Bend diameter rate is larger, and the fluid speed recovers faster, and the velocity is smaller, and the unit pressure drop is smaller, and Unit pressure drop is down 72.9%. The increase of Reynolds number can reduce the resistance coefficient of the Bend part, but the increase of the Bend diameter rate makes the resistance coefficient decrease first and then increase.

The soaking process of glutinous rice allows the growth and reproduction of microorganisms, which can easily cause food safety problems. In this work, the effects of different ultrasonic powers (150 W, 300 W, 450 W, and 600 W) on the bactericidal effect of glutinous rice, the physicochemical properties of starch and the quality characteristics of sweet dumplings were studied. Compared with soaking for 0 and 2 h, sonication of glutinous rice after soaking for 4 h was more effective at reducing the number of microorganisms in soaked glutinous rice, and the bactericidal effect increased with increasing ultrasound intensity. After 30 min, the total number of bacteria decreased by 2.04 log CFU/g. Moreover, ultrasonic treatment destroys the grain structure of glutinous rice starch, resulting in the formation of dents and cracks on the starch surface, increasing the amylose content, improving its expansion, reducing its short-range order and relative crystallinity, and altering its gelatinization characteristics. In addition, ultrasonic treatment increased the soup transparency of sweet dumplings from 51.8 % to 63.95 %, reducing their hardness, chewiness and adhesiveness. In summary, ultrasonic treatment can not only effectively kill microorganisms in soaked glutinous rice but also improve the quality of glutinous rice dumplings by changing the physicochemical properties of glutinous rice starch. The results of this study provide theoretical support for the application of ultrasonic technology in glutinous rice food production.

Precise long-term runoff prediction holds crucial significance in water resource management. Although the long short-term memory (LSTM) model is widely adopted for long-term runoff prediction, it encounters challenges such as error accumulation and low computational efficiency. To address these challenges, we utilized a novel method to predict runoff based on a Transformer and the base flow separation approach (BS-Former) in the Ningxia section of the Yellow River Basin. To evaluate the effectiveness of the Transformer model and its responsiveness to the base flow separation technique, we constructed LSTM and artificial neural network (ANN) models as benchmarks for comparison. The results show that Transformer outperforms the other models in terms of predictive performance and that base flow separation significantly improves the performance of the Transformer model. Specifically, the performance of BS-Former in predicting runoff 7 days in advance is comparable to that of the BS-LSTM and BS-ANN models with lead times of 4 and 2 days, respectively. In general, the BS-Former model is a promising tool for long-term runoff prediction. HIGHLIGHTS The effectiveness of a Transformer model for simulating and predicting long-term daily runoff is explored.; The response of the Transformer model to prior hydrological knowledge in base flow separation is analyzed.; The potential of base flow separation techniques to improve the ability to predict the runoff lead time in deep learning models is explored.;

Abstract Interfacial electronic structure modulation of nickel‐based electrocatalysts is significant in boosting energy‐conversion‐relevant urea oxidation reaction (UOR). Herein, porous carbon nanofibers confined mixed Ni‐based crystal phases of Ni2P and NiF2 are developed via fluorination and phosphorization of Ni coated carbon nanofiber (Ni2P/NiF2/PCNF), which possess sufficient mesoporous and optimized Gibbs adsorption free energy by mixed phase‐induced charge redistribution. This novel system further reduces the reaction energy barrier and improves the reaction activity by addressing the challenges of low intrinsic activity, difficulty in active site formation, and insufficient synergism. A considerably high current density of 254.29 mA cm−2 is reached at 1.54 V versus reversible hydrogen electrode on a glass carbon electrode, and the cell voltage requires 1.39 V to get 10 mA cm−2 in hydrogen generation, with very good stability, about 190 mV less than that of the traditional water electrolysis. The facile active phase formation and high charge transfer ability induced by asymmetric charge redistribution are found in the interface, where the urea molecules tend to bond with Ni atoms on the surface of heterojunction, and the rate‐determining step is changed from CO2 desorption to the fourth H‐atom deprotonation. The work reveals a novel catalyst system by interfacial charge redistribution induced by high bond polarity for energy‐relevant catalysis reactions.

In recent years, mobile payment has gained widespread popularity and has become the main payment method for many consumers in China. With the increase in user scale and usage frequency, the scale of mobile payment transactions will continue to grow in the future. This study aimed at investigating the impact of electronic payment platform service characteristics on customer usage intentions in a user-centered study in China. This study made use of SPSS 22.0 handles basic statistics, while the statistical tool Smart PLS 3.0 handles hypothesis testing. A survey of 70 people who used electronic payment platforms was conducted. Results of the study revealed that between electronic payment platform service characteristics, convenience, security, reliability, and reactivity. The impact on customer usage intention and usage behavior is as follows: characteristics, convenience, security, reliability, and reactivity of electronic payment platform services. The results of the survey showed that users' attitudes towards usage and user behavior had a positive impact.

The galvanic cell is a typical interdisciplinary topic, which is primarily taught in chemistry but its underpinning is closely related to physics. Student learning in galvanic cell has been extensively studied in chemistry education, which has revealed a large number of misconceptions that are difficult to change through traditional instruction. A source of the learning difficulties is that most students lack an explanatory framework to integrate the many complex phenomena and processes into a coherent knowledge system. As a result, students often rely on memorization of terms, laws, and equations in solving problems but without a meaningful understanding of their reasoning. To address the deficit in learning, this study aims to help students develop an explanatory framework for supporting an integrated knowledge structure. Specifically, a conceptual framework model for galvanic cell is developed based on the central idea from physics, which is used as the core concept for mechanistic explanations of the related chemistry concepts. Guided by the conceptual framework, an instrument is developed to assess the knowledge integration in student learning of galvanic cell. A combination of qualitative and quantitative measures was used to assess the levels of knowledge integration in learning galvanic cell with a large number of Chinese high school and college students. The assessment results show that the conceptual framework model can effectively represent the knowledge structures of students at different levels of knowledge integration. The galvanic cell conceptual framework and assessment results can provide useful resources for teachers to develop instruction for promoting knowledge integration.

Liquid-like surfaces have demonstrated immense potential in their ability to resist cell adhesion, a critical requirement for numerous applications across various domains. However, the conventional methodologies for preparing liquid-like surfaces often entail a complex multi-step polymer brush modification process, which is not only time-consuming but also presents significant challenges. In this work, we developed a single-cycle polymer brush modification strategy to build liquid-like surfaces by leveraging high-molecular-weight bis(3-aminopropyl)-terminated polydimethylsiloxane, which significantly simplifies the preparation process. The resultant liquid-like surface is endowed with exceptional slipperiness, effectively inhibiting bacterial colonization and diminishing the adherence of platelets. Moreover, it offers promising implications for reducing the dependency on anticoagulants in microfluidic systems constructed from PDMS, all while sustaining its antithrombotic attributes.

Adopting drought-tolerant (DT) cultivars is an effective strategy to sustain maize (Zea mays L.) production under water shortage. Optimizing plant density is an important management practice for improving maize yield. In a two-year field trial, the response of yield, actual evapotranspiration (ETc act), and water productivity (WP) to plant density (6, 7.5, 9 plants m−2) was assessed under irrigated and rainfed conditions using a DT (ZD958) and a drought-susceptible (DS, ZY309) maize cultivar, and additionally, the comparison of soil water depletion will be conducted among soils growing different DT maize varieties. Under rainfed, average yield, ETc act, and WP were 24.7%, 8.6% and 14.8% greater in ZD958 than ZY309, respectively. When density increased from 6 to 9 plants m−2, for ZD958 and ZY309 ETc act remained relatively constant, whereas their yield and WP first increased and then decreased and ultimately reached their maximum at 7.5 plants m−2. Under irrigation, increasing density (6–9 plants m−2) significantly increased yield and WP for ZD958, but for ZY309, yield and WP were not significantly impacted. Yield across seasons did not differ between cultivars at 6 and 7.5 plants m−2, and ZD958 had a 10.2% yield advantage over ZY309 at 9 plants m−2. The findings imply that DT cultivar showed greater high density tolerance than DS cultivar and thus higher optimal density under irrigation. Under rainfed, both cultivars had similar density tolerance and optimum density, whereas DT cultivar had stronger drought tolerance than DS cultivar, which could explain DT cultivar’s greater yield and WP. This study indicate that DT cultivar showed higher and more stable yields than DS cultivar across rainfed and irrigated conditions when grown at optimal densities. Thus, sustainable maize production could be achieved by adopting DT cultivars and optimizing density for different conditions in the study region.

In seasonal agricultural frozen soil areas, the straw return may influence the freeze–thaw characteristics by changing the soil organic matter and porosity. Monitoring moisture and heat in the freeze–thaw period is significant for preventing spring waterlogging and reasonable planting arrangements. However, the effect of long-term straw return on the soil freeze–thaw process is still unclear. In this study, we investigated the dynamics of soil temperature (ST) and soil moisture (SM) between straw-return cropland (SF) for 29 consecutive years and no-fertilization cropland (NF) during freeze–thaw progress in northeast China. The soil in both sites underwent unidirectional freezing and bidirectional thawing processes. The soil freezing and thawing dates in the NF of the profile occurred earlier than that in the SF. The NF had higher frozen depth and freezing rate than the SF and exhibited a larger range of ST variation and higher heat transmission efficiency. The SM showed a declining trend before the ST started to decrease to a freezing point at different depths in both sites. The migrated SM in most soil layers decreased during monitoring. The relationship between SM and negative ST was a power function at different frozen depths. The SM decreased rapidly in the range of −2–0 °C in both sites. During phase changes, the SF and NF consumed 33.0 and 43.6 MJ m−2, respectively. The results can partially explain the response of straw return to soil hydrothermal variation during the freeze-thaw process. This study may provide an integral theory for effectively utilizing agricultural soil hydrothermal resource in northeast China.

Inducible nitric oxide synthase (iNOS), regulated by nuclear factor kappa B (NF-κB), is crucial for intestinal inflammation and barrier injury in the progression of necrotizing enterocolitis (NEC). The NF-κB pathway is inhibited by S-glutathionylation of inhibitory κB kinase β (IKKβ), which can be restored by glutaredoxin-1 (Grx1). Thus, we aim to explore the role of Grx1 in experimental NEC. Wild-type (WT) and Grx1-knockout (Grx1−/−) mice were treated with an NEC-inducing regimen. Primary intestinal epithelial cells (IECs) were subjected to LPS treatment. The production of iNOS, NO, and inflammation injuries were assessed. NF-κB and involved signaling pathways were also explored. The severity of NEC was attenuated in Grx1−/− mice. Grx1 ablation promoted IKKβ glutathionylation, NF-κB inactivation, and decreased iNOS, NO, and O2·– production in NEC mice. Furthermore, Grx1 ablation restrained proinflammatory cytokines and cell apoptosis, ameliorated intestinal barrier damage, and promoted proliferation in NEC mice. Grx1 ablation protected NEC through iNOS and NO inhibition, which related to S-glutathionylation of IKKβ to inhibit NF-κB signaling. Grx1-related signaling pathways provide a new therapeutic target for NEC.

Age-related hearing loss (ARHL) is a common neurodegenerative disease. Its molecular mechanisms have not been fully elucidated. In the present study, we obtained differential mRNA expression in the cochlea of 2-month-old miR-29a+/+ mice and miR-29a−/− mice by RNA-seq. Gene ontology (GO) analysis was used to identify molecular functions associated with hearing in miR-29a−/− mice, including being actin binding (GO: 0003779) and immune processes. We focused on the intersection of differential genes, miR-29a target genes and the sensory perception of sound (GO:0007605) genes, with six mRNA at this intersection, and we selected Col1a1 as our target gene. We validated Col1a1 as the direct target of miR-29a by molecular and cellular experiments. Total 6 pathways involved in Col1a1 were identified by through Kyoto Encyclopedia of Genes and Genomes (KEGG) pathway enrichment analysis. We selected the focal adhesion pathway as our target pathway based. Their expression levels in miR-29a−/− mice were verified by qRT-PCR and Western blot. Compared with miR-29a+/+ mice, the expression levels of Col1a1, Itga4, Itga2, Itgb3, Itgb7, Pik3r3 and Ptk2 were different in miR-29a−/− mice. Immunofluorescence was used to locate genes in the cochlea. Col1a1, Itga4 and Itgb3 were differentially expressed in the basilar membranes and stria vascularis and spiral ganglion neurons compared to miR-29a+/+ mice. Pik3r3 and Ptk2 were differentially expressed in the basilar membranes and stria vascularis, but not at the s spiral ganglion neurons compared to miR-29a+/+ mice.Our results show that when miR-29a is knocked out, the Col1a1 mediates the focal adhesion pathway may affect the hearing of miR-29a−/− mice. These findings may provide a new direction for effective treatment of age-related hearing loss.

Micro light-emitting diodes (micro-LEDs) are considered crucial for the next-generation display technology. However, the high cost of large-scale transfer technology and the lack of maturity in full-color technology have hindered the availability of mature products. The perovskite quantum dot (PQD) material offers a promising solution for achieving full-color capabilities in micro-LED displays. This review article aims to provide an overview on the latest progresses on PQD full-color technology for micro-LEDs. The review covers a variety of patterning techniques, including photolithography, inkjet printing, microfluidic processing, and laser processing, as well as the research on intrinsic stability of PQDs. Finally, the current drawbacks and solutions of PQD color conversion micro-LEDs are discussed, and the future research prospects in this field are anticipated.

Objectives Previous studies on the mechanism and scope of interosseous membrane injury in Maisonneuve fractures have been inconsistent. In order to better guide clinical treatment, the characteristics and mechanism of interosseous membrane injuries and proximal 1/3 fibular fracture in typical Maisonneuve fracture were investigated. Methods The study comprised 15 patients between January 2019 and June 2021 with Maisonneuve fracture. All patients received X‐ray and MRI examination of the calf and ankle joint, and CT scanning of the ankle joint. The injuries of medial structure, inferior tibiofibular syndesmosis, fibula, posterior malleolus, and interosseous membrane were evaluated. Results MR images of the calf showed that the injury of interosseous membrane (IOM) was from the syndesmosis to the proximal fibular fracture site in two patients, with a range of 32.3 and 29.8 cm, respectively. In the other 13 patients, the IOM rupture was not only confined to the distal third of the calf, but also close to the fibula fracture, and the IOM was intact between the two fracture sites. The range of distal IOM rupture was 3.7–12.2 cm, with an average of 8.06 ± 2.35 cm. The proximal IOM was completely ruptured from the fibular side at the site of the fibular fracture and the range was 4.1–9.1 (average: 6.75 ± 1.64) cm. The average length of the integrate middle segment of the IOM was 14.55 ± 4.11 (5.6–20.3) cm. MR images of the calf also showed partial rupture of the posterior tibial muscle at the ending point on the fibula in 15 cases, partial rupture of soleus muscle and flexor hallucis longus in seven cases. Conclusions The rupture of the IOM was caused by a combination of abduction and external rotation violence. It was manifested in two forms, most of which was not only distal end but also near fibular fracture site ruptures with the middle part intact, and a few were ruptures of the IOM from the ankle to the near fibular fracture site. The tibialis posterior muscle may be related to the location of the fibular fracture.

The takeoff process of a seaplane is different from that of a conventional land-based plane owing to the influence of hydrostatic, hydrodynamic, and aerodynamic forces. As a result, more energy will be consumed by the electric propulsion unit (EPU) of a seaplane during takeoff. Given the limited energy density of contemporary batteries, the energy consumed by the seaplane during its flight mission profile was minimized in this study by improving the efficiency of the EPU using a proposed optimization method. To meet the performance requirements of the seaplane EPU, the pitch angle of the propeller was taken as the optimization variable and the system loss was mathematically modeled. The performance of the EPU was thereby optimized, its consumption during flight was reduced, and the seaplane endurance was increased accordingly. The proposed optimization method was subsequently verified using a prototype test of a two-seat electric seaplane. The results show that the proposed method can reduce the energy consumption of the EPU by more than 5% during a single flight.

Land degradation severely affects soil functions, thereby weakening crop productivity. However, the quantitative effects of the soil organic matter (SOM) composition and soil microbial properties on maize yield remain unclear under different levels of land degradation. Here, a gradient of land degradation was selected for sampling in the Horqin Sandy Land in northeast China. The results show that the relative abundances of aliphatic and aromatic groups decreased by 21.51% and 86.01% with increasing land degradation, respectively, and the considerable increase in polysaccharide groups led to a decrease in stability and resistance to SOM decomposition. Microbial properties, such as microbial biomass carbon, basic respiration, qCO2, and enzyme activities, decreased as a result of land degradation. The phospholipid fatty acid content and the ratio between bacteria and fungi markedly decreased with an increasing level of land degradation, and the ratio of G+ to G− markedly increased. Correlation analysis confirmed that the microbial properties were significantly related to the SOM composition, and the random forest model indicated that fungi were key factors affecting maize yield (7.15%, p < 0.05). Moreover, the results of the structure equation modelling revealed that land degradation reduced the soil physiochemical properties, resulting in a decrease in microorganisms, causing variations in the SOM composition and directly leading to a decrease in crop yield. The effect of microorganisms (β = 0.84 ***) on maize yield was greater than that of the SOM composition (β = 0.53 **). Our investigation can provide a theoretical basis for the conservation of the cropland in Horqin Sandy Land.

Streaming potential is mainly related to electrokinetic energy conversion, which has been considered to show promising potential for advanced technologies, especially sensing. The inherent property of streaming potential is that the energy conversion process is always a continuous state. However, practical applications include many cases of discontinuous states, such as nonlinear sensing. Here, we report a discontinuous streaming potential electrokinetic energy conversion fluid system. Experiments and theoretical calculations reveal that this system exhibits a discontinuous electrokinetic effect and provides a gating liquid slip in micropores, offering the advantages of gating liquid charge coupling and interfacial drag reduction. Moreover, the system is demonstrated in a wearable fall-down alert application. We expect this liquid gating energy conversion system to open up a platform for the design and application of autonomous health monitoring devices, seismic sea wave warning systems, and beyond.

Abstract Sulfur cathodes in Li–S batteries suffer significant volumetric expansion and lack of catalytic activity for polysulfide conversion. In this study, a confined self‐reduction synthetic route is developed for preparing nanocomposites using diverse metal ions (Mn2+, Co2+, Ni2+, and Zn2+)‐introduced Al‐MIL‐96 as precursors. The Ni2+‐introduced Al‐MIL‐96‐derived nanocomposite contains a “hardness unit”, amorphous aluminum oxide framework, to restrain the volumetric expansion, and a “softness unit”, Ni nanocrystals, to improve the catalytic activity. The oxygen‐potential diagram theoretically explains why Ni2+ is preferentially reduced. Postmortem microstructure characterization confirms the suppressive volume expansion. The in situ ultraviolet–visible measurements are performed to probe the catalytic activity of polysulfide conversion. This study provides a new perspective for designing nanocomposites with “hardness units” and “softness units” as sulfur or other catalyst hosts.

The electric seaplane, designed for take-off and landing directly on water, incorporates additional structures such as floats to meet operational requirements. Consequently, during the take-off taxiing phase, it encounters significantly higher aerodynamic and hydrodynamic resistance than other aircraft. This increases energy demand for the electric seaplane during the take-off phase. A mathematical model for energy consumption during this stage was developed by analyzing resistance, using the propeller pitch angle as an optimization variable. This study proposes a coupled energy efficiency optimization method for the take-off phase of an electric seaplane’s electric propulsion unit (EPU). The method aims to determine an optimal propeller pitch angle configuration aligned with the seaplane’s design criteria. This ensures that the propeller output thrust meets minimal requirements during take-off while enhancing energy efficiency. Experimental validation with the two-seater electric seaplane prototype RX1E-S has demonstrated that selecting the optimal propeller pitch angle can effectively reduce energy consumption by approximately 10.4%, thereby significantly enhancing flight efficiency.

Summary Protective efficiency of a combination of four recombinant Brucella abortus (B. abortus) proteins, namely, ribosomal protein L7/L12, outer membrane protein (OMP) 22, OMP25 and OMP31, was evaluated as a combined subunit vaccine (CSV) against B. abortus infection in RAW 264.7 cell line and murine model. Four proteins were cloned, expressed and purified, and their immunocompetence was analysed. BALB/c mice were immunized subcutaneously with single subunit vaccines (SSVs) or CSV. Cellular and humoral immune responses were determined by ELISA. Results of immunoreactivity showed that these four recombinant proteins reacted with Brucella‐positive serum individually but not with Brucella‐negative serum. A massive production of IFN‐γ and IL‐2 but low degree of IL‐10 was observed in mice immunized with SSVs or CSV. In addition, the titres of IgG2a were heightened compared with IgG1 in SSV‐ or CSV‐immunized mice, which indicated that SSVs and CSV induced a typical T‐helper‐1‐dominated immune response in vivo. Further investigation of the CSV showed a superior protective effect in mice against brucellosis. The protection level induced by CSV was significantly higher than that induced by SSVs, which was not significantly different compared with a group immunized with RB51. Collectively, these antigens of Brucella could be potential candidates to develop subunit vaccines, and the CSV used in this study could be a potential candidate therapy for the prevention of brucellosis.

Abstract Otitis media (OM) is a common disease that can cause hearing loss in children. Currently, the main clinical treatment for OM is antibiotics, but the overuse of antibiotics might lead to bacterial resistance, which is a worldwide public health challenge. Studying the pathogenesis of OM will help us develop new effective treatments. Ferroptosis is one type of programmed cell death characterized by the occurrence of lipid peroxidation driven by iron ions. Many studies have shown that ferroptosis is associated with infectious diseases. It is presently unclear whether ferroptosis is involved in the pathogenesis of OM. In this study, we explored the relationship between ferroptosis and OM by PGPS-induced OM in C57BL/6 mice and treating the induced OM with ferroptosis inhibitors deferoxamine (DFO), Ferrostatin-1 (Fer-1), and Liperoxstatin-1 (Lip-1). We examined the expression of ferroptosis-related proteins acyl-CoA synthetase long chain family member 4 (ACSL4) and prostaglandin-endoperoxide synthase 2 (Cox2), glutathione peroxidase 4 (GPX4) protein as well as lipid peroxidation markers 4-hydroxynonenal (4-HNE) and malondialdehyde (MDA). The results showed that in PGPS-induced OM model mice, several ferroptosis-related proteins including ACSL4 and Cox2 were up-regulated compared to mice treated with saline. Meanwhile, a ferroptosis-related protein GPX4 was down-regulated upon PGPS treatment. The DFO treatment in PGPS-inoculated mice effectively inhibited the development of OM. The inhibitors treatment caused a significant decrease in the expression of ACSL4, Cox2, 4 HNE, MDA, reduction in free iron. Meanwhile, the ferroptosis inhibitors treatment caused increase in the expression of inflammation-related factors tumor necrosis factor-α (TNF-α) and antioxidant protein GPX4. Our results suggest that there is a crosstalk between ferroptosis signaling pathway and the pathogenesis of OM. Ferroptosis inhibition can alleviate PGPS-induced OM.

With the development of long-distance power transmission system, the electrochemical corrosion of buried oil and gas pipelines caused by stray current is becoming more serious. In particular, the grounding current interference of High Voltage Direct Current (HVDC) transmission system will cause serious electrochemical corrosion at the defects of pipeline anti-corrosion coating, which threatens the operation safety of pipelines. In this case, the stray current density distribution along the buried pipelines close to the grounding electrode was simulated and analyzed with the COMSOL software. Meanwhile, study was performed for the influence laws of various interference parameters (including the angle between pipeline and cable of HVDC system, the grounding current, the soil conductivity, the distance between pipeline and grounding electrode, and the pipeline radius) on stray current density distribution and interference corrosion along the pipelines. The results indicate that the interference corrosion is enhanced greatly when the distance between the pipeline and any grounding electrode was less than 5 km, and it is the most serious when the angle between the pipeline and the cable is 0°. In addition, other parameters also have great influence on the interference corrosion of pipeline. Therefore, the study results could provide theoretical basis and reference for the interference protection, maintenance and inspection of pipelines.

Shape memory materials with controllable property for harsh condition like high temperature are strongly required. Here, three novel shape memory polyimides (SMPIs) have been realized by bearing various side-chain groups (-H, –CH3 or –OCH3) to study their relationship between structures and shape memory performances. These PIs possess excellent shape memory behaviors in both fixity ratio (Rf > 99.1%) and recovery ratio (Rr > 86.8%). The rheological information revealed different creep and stress relaxation accompanied with the different SMPIs. Meanwhile, fractional free volume (FFV) and simulating of geometry optimized molecule chain via Materials Studio were referred to reveal the inner relationship between shape memory performance and polymer structure. This work provides a design metric to guiding significance to the structure design of shape memory polyimides.

IntroductionSerum Cystatin C level, an indication of kidney function, has been implicated in the pathogenesis of Alzheimer’s disease and cognitive impairment. In this cross-sectional study, we looked into the relation between serum Cystatin C levels and cognition in a group of U.S. older adults.MethodThe data of this study were from the National Health and Nutrition Examination Survey (NHANES) 1999–2002. A total of 4,832 older adults aged ≥60 who met the inclusion criteria were included. The Dade Behring N Latex Cystatin C assay, which is a particle-enhanced nephelometric assay (PENIA), was utilized to assess Cystatin C levels in participants’ blood samples. Participants’ cognition was examined using the digit symbol substitution test (DSST). Z-scores of the DSST were calculated based on sample means and standard deviations (SD). To investigate the relationships between the quartiles of serum Cystatin C level and DSST z scores, multiple linear regression models were developed while controlling for age, sex, race/ethnicity, and education.ResultsThe average age of the participants was 71.1 (SD 7.8). The participants were about half female (50.5%), non-Hispanic White (61.2%), and (36.1%) who had completed at least some college. They had an average serum Cystatin C level of 1.0 mg/dl (SD 0.44). After performing multiple linear regression with a reference group consisting of participants in quartile one of plasma Cystatin C levels, we found that serum Cystatin C levels in quartiles three and four were independently associated with lower DSST z scores (β = −0.059, 95% CI −0.200 to −0.074 and β = −0.108, 95% CI −0.319 to −0.184, respectively).ConclusionHigher serum Cystatin C level is associated with worse processing speed, sustained attention, and working memory in older adults. Cystatin C level may be a biomarker for cognitive decline in older adults.

Age-related hearing loss (ARHL) is the most common sensory degenerative disease and can significantly impact the quality of life in elderly people. A previous study using GeneChip miRNA microarray assays showed that the expression of miR-29a changes with age, however, its role in hearing loss is still unclear. In this study, we characterized the cochlear phenotype of miR-29a knockout (miR-29a–/–) mice and found that miR-29a-deficient mice had a rapid progressive elevation of the hearing threshold from 2 to 5 months of age compared with littermate controls as measured by the auditory brainstem response. Stereocilia degeneration, hair cell loss and abnormal stria vascularis (SV) were observed in miR-29a–/– mice at 4 months of age. Transcriptome sequencing results showed elevated extracellular matrix (ECM) gene expression in miR-29a–/– mice. Both Gene Ontology (GO) annotation and Kyoto Encyclopedia of Genes and Genomes (KEGG) pathway enrichment analysis revealed that the key differences were closely related to ECM. Further examination with a transmission electron microscope showed thickening of the basilar membrane in the cochlea of miR-29a–/– mice. Five Col4a genes (Col4a1-a5) and two laminin genes (Lamb2 and Lamc1) were validated as miR-29a direct targets by dual luciferase assays and miR-29a inhibition assays with a miR-29a inhibitor. Consistent with the target gene validation results, the expression of these genes was significantly increased in the cochlea of miR-29a–/– mice, as shown by RT-PCR and Western blot. These findings suggest that miR-29a plays an important role in maintaining cochlear structure and function by regulating the expression of collagen and laminin and that the disturbance of its expression could be a cause of progressive hearing loss.

Cervical cancer (CC) remains one of the leading causes of cancer-related deaths worldwide. However, cervical cancer is preceded by the pre-malignant cervical intraepithelial neoplasia (CIN) that can last for up to 20 years before becoming malignant. Therefore, early screening is the key to prevent the progression of cervical lesions into invasive cervical cancer and decrease the incidence. The genes, down-regulated and hypermethylated in cancers, may provide potential drug targets for cervical cancer. In our current study, using the datasets from Gene Expression Omnibus (GEO) and the Cancer Genome Atlas (TCGA) databases, we found that endothelin 3 (EDN3) was downregulated and hypermethylated in cervical squamous cell carcinoma (CSCC). The further analysis in GSE63514 (n=128) dataset and in our samples (n=221) found that the expression of EDN3 was decreased with the degree of cervical lesions. Pyrosequencing was performed to evaluate 4 CpG sites of the EDN3 promoter region in our samples (n=469). The data indicated that the methylation level of EDN3 was increased with the degree of cervical lesions. EDN3 silencing mediated by methylation can be blocked by 5-Azacytidine (5-Aza), a DNA methyltransferase 1 (DNMT1) inhibitor, treatment in cervical cancer cell lines. Ethynyldeoxyuridine (EdU) assay, would-healing assay, clone formation assay and transwell assay were conducted to investigate the biological function of EDN3 in cervical cancer cell lines. The results of these experiments confirmed that overexpression of EDN3 could inhibit the proliferation, clone formation, migration and invasion of cervical cancer cells. EDN3 may provide potential biomarker and therapeutic target for CSCC.

The wound healing process is usually susceptible to different bacterial infections due to the complex physiological environment, which significantly impairs wound healing. The topical application of antibiotics is not desirable for wound healing because the excessive use of antibiotics might cause bacteria to develop resistance and even the production of super bacteria, posing significant harm to human well-being. Wound dressings based on adhesive, biocompatible, and multi-functional hydrogels with natural antibacterial agents have been widely recognized as effective wound treatments. Hydrogels, which are three-dimensional (3D) polymer networks cross-linked through physical interactions or covalent bonds, are promising for topical antibacterial applications because of their excellent adhesion, antibacterial properties, and biocompatibility. To further improve the healing performance of hydrogels, various modification methods have been developed with superior biocompatibility, antibacterial activity, mechanical properties, and wound repair capabilities. This review summarizes hundreds of typical studies on various ingredients, preparation methods, antibacterial mechanisms, and internal antibacterial factors to understand adhesive hydrogels with natural antibacterial agents for wound dressings. Additionally, we provide prospects for adhesive and antibacterial hydrogels in biomedical applications and clinical research.

Scientific and accurate estimation of rice yield is of great significance to food security protection and agricultural economic development. Due to the weak penetration of high frequency microwave band, most of the backscattering comes from the rice canopy, and the backscattering coefficient is highly correlated with panicle weight, which provides a basis for inversion of wet biomass of rice ear. To solve the problem of rice yield estimation at the field scale, based on the traditional water cloud model, a modified water-cloud model based on panicle layer and the radar data with Ku band was constructed to estimate rice yield at panicle stage. The wet weight of rice ear scattering model and grain number per rice ear scattering model were constructed at field scale for rice yield estimation. In this paper, the functional area of grain production in Xiashe Village, Xin'an Town, Deqing County, Zhejiang Province, China was taken as the study area. For the first time, the MiniSAR radar system carried by DJI M600 UAV was used in September 2019 to obtain the SAR data with Ku band under polarization HH of the study area as the data source. Then the rice yield was estimated by using the newly constructed modified water-cloud model based on panicle layer. The field investigation was carried out simultaneously for verification. The study results show: the accuracies of the inversion results of wet weight of rice ear scattering model and grain number per rice ear scattering model in parcel B were 95.03% and 94.15%; and the accuracies of wet weight of rice ear scattering model and grain number per rice ear scattering model in parcel C+D+E were over 91.8%. In addition, different growth stages had effects on yield estimation accuracy. For rice at fully mature, the yield estimation accuracies of wet weight of ear and grain number per ear were basically similar, both exceeding 94%. For rice at grouting stage, the yield estimation accuracy of wet weight of ear was 92.7%, better than that of grain number per ear. It was proved that it can effectively estimate rice yield using the modified water-cloud model based on panicle layer constructed in this paper at panicle stage at field scale.

Combining magnetic and semiconducting properties in a single material offers great technological potential, all the more so if these are coupled with good optical properties. Here, Neumann et al. present a Manganese doped Ruddlesden-Popper perovskite with this trifecta of attributes.

Abstract Research on how plant ecological strategies (competitive, stress‐tolerant, or ruderal) vary within species may improve our understanding of plant and community responses to climate warming and also successional changes. With increasing temperature, the importance of ruderal (R) and stress tolerance (S) components is hypothesized to decrease, while the strength of the competitive (C) component should increase. Offshoots and younger plants are predicted to have greater R and smaller S components. Leaf area, leaf dry matter content, and specific leaf area were measured for 1,344 forest plants belonging to 134 species in Liangshui and Fenglin Nature Reserves in Northeastern China, and C, R, and S scores calculated for each. Linear mixed effect models were used to assess how these indicators differed among study sites (n = 2), regeneration types, ontogenetic stages, and plant life forms. The two study sites have an average annual temperature difference of 0.675°C, simulating a temperature increase of 0.630°C due to climate warming. Higher temperatures reduce low‐temperature stress and frost damage, which may explain the observed decrease in R and S scores; at the same time, plant competitive ability increased, as manifested by higher C scores. This effect was most pronounced for herbaceous plants, but nearly negligible as compared to the effect of regeneration type for trees and of ontogeny for woody species. Resprouting trees and younger woody plants had higher R scores and lower S scores, a sign of adaptation to high disturbance. In this study, a small increase in mean annual temperature led to shifts in CSR strategy components for herbaceous species, without altering the vegetation type or community composition. Offshoots and younger plants had higher R and lower S scores, shedding light on similar changes in the ecological strategies of tree communities during secondary succession, such as the transition of Quercus mongolica coppices to forest and age‐related changes in Populus davidiana–Betula platyphylla forests.

Water splitting has been regarded as a sustainable and environmentally-friendly technique to realize green hydrogen generation, while more energy is consumed due to the high overpotentials required for the anode oxygen evolution reaction. Urea electrooxidation, an ideal substitute, is thus received increasing attention in assisting water-splitting reactions. Note that highly efficient catalysts are still required to drive urea oxidation, and the facile generation of high valence state species is significant in the reaction based on the electrochemical-chemical mechanisms. The high cost and rareness make the noble metal catalysts impossible for further consideration in large-scale application. Ni-based catalysts are very promising due to their cheap price, facile structure tuning, good compatibility, and easy active phase formation. In the light of the significant advances made recently, herein, we reviewed the recent advances of Ni-based powder catalysts for urea oxidation in assisting water-splitting reaction. The fundamental of urea oxidation is firstly presented to clarify the mechanism of urea-assisted water splitting, and then the prevailing evaluation indicators are briefly expressed based on the electrochemical measurements. The catalyst design principle including synergistic effect, electronic effect, defect construction and surface reconstruction as well as the main fabrication approaches are presented and the advances of various Ni-based powder catalysts for urea assisted water splitting are summarized and discussed. The problems and challenges are also concluded for the Ni-based powder catalysts fabrication, the performance evaluation, and their application. Considering the key influencing factors for catalytic process and their application, attention should be given to structure−property relationship deciphering, novel Ni-based powder catalysts development and their construction in the real device; specifically, the effort should be directed to the Ni-based powder catalyst with multi-functions to simultaneously promote the fundamental steps and high anti-corrosion ability by revealing the local structure reconstruction as well as the integration in the practical application. We believe the current summarization will be instructive and helpful for the Ni-based powder catalysts development and understanding their catalytic action for urea-assisted hydrogen generation via water splitting technique.

In our study, two popular fragrant rice cultivars (Meixiangzhan 2 and Xiangyaxiangzhan) were conducted by three treatments (CK: conventional tillage; T1: minimum tillage; T2: no-tillage) to assess the effects of conservation tillage on the aroma, yield and quality of mechanical-transplanting fragrant rice. Results depicted that the 2-acetyl-1-pyrroline (2-AP) content in mature grains of mechanical-transplanting fragrant rice remained high level under T1 and T2 treatments. 2-AP accumulation in mature grains was significant associated with the 2-AP, proline and pyrroline-5-carboxylic acid content, proline dehydrogenase and ornithine aminotransferase activity in grains and leaves during the grain-filling period. T1 and T2 treatments improved yield components, increased the photosynthetic matter accumulation, and increased yields. T1 and T2 treatments also resulted in a higher head milled rice rate and significant changes in protein content of mechanical-transplanting fragrant rice. Overall, conservation tillage practices were beneficial to increase the 2-AP content, quality and yield of mechanical-transplanting fragrant rice.

2-acetyl-1-pyrroline (2AP) is recognized as the key aromatic compound in fragrant rice, however, the effect of light quality on rice aroma is not fully understood. In this study, two fragrant rice varieties (Xiangyaxiangzhan and Yuxiangyouzhan) were grown under four light quality treatments (CK: natural light, L1: red light, L2: blue light and L3: combined light). Results depicted that L1, L2 and L3 treatments enhanced the grain yield by 14.24–35.36%, compared to CK whilst L2 and L3 treatments reduced the 2AP content in grains by 17.18–28.68%. Moreover, L1, L2 and L3 treatments enhanced the grain yield owing to improved filled grain percentage and regulation in antioxidant enzyme activities. On the other hand, L2 and L3 reduced the 2AP content in grains by decreasing pyrroline-5-carboxylic acid content and modulating proline and γ-aminobutyric acid content. Overall, this study revealed that light quality substantially affects the grain yield and quality characters of fragrant rice.

IntroductionContrast-enhanced transcranial Doppler (c-TCD) is a noninvasive test with high sensitivity for the detection of a right-to-left shunt (RLS). Currently, there are no reports on the outcomes of unilateral versus bilateral middle cerebral artery (MCA) monitoring. This study compared the positivity rate of bilateral MCA monitoring with unilateral MCA monitoring for RLS using c-TCD.MethodsWe enrolled 239 patients (86 women and 153 men) with a mean age of 48.54 ± 13.25 years (range, 14–79 years), who underwent c-TCD examination in the Department of Transcranial Doppler Ultrasound of our hospital between February 2018 and February 2021, due to suspicion of RLS. Bilateral MCA monitoring of 239 patients was performed using dual-channel and dual-depth c-TCD. The positive rate and shunt classification of RLS were calculated for left, right, and bilateral MCA monitoring. The differences in RLS detected by c-TCD monitoring of the left, right and bilateral MCA were compared.ResultsIn the left middle cerebral artery (LMCA) monitoring, 35.56% (85 of 239) had a positive RLS result, 38 cases were permanent (44.70%), and 47 cases were latent (55.30%). In the right middle cerebral artery (RMCA) monitoring, 36.82% (88 of 239) had a positive RLS result, 38 cases were permanent (43.18%), and 50 cases were latent (56.82%). In the bilateral MCA group, 43.09% (103 of 239) had a positive RLS result, 50 cases were permanent (48.54%) and 53 were latent (51.46%). The positive rate of bilateral MCA monitoring was higher than that of LMCA and RMCA (43.09, 35.56, and 36.82%, respectively), and the difference was not statistically significant (P = 0.193). The positive rate of bilateral MCA monitoring was higher than that of LMCA and RMCA for mild and moderate shunts, but the difference was not statistically significant. The positive rate of bilateral MCA monitoring was equal to that of RMCA, but higher than that of LMCA, with no statistical significance. LMCA monitoring revealed 85 patients with RLS. The sensitivity was 82.52% (85/103). The specificity was 100%. The RMCA monitoring results showed 88 cases with RLS. The sensitivity was 85.44% (88/103). The specificity was 100%.ConclusionsThere was no significant difference in the RLS detection rate between unilateral and bilateral MCA monitoring using c-TCD. Bilateral MCA monitoring may be more advantageous for mild RLS detection.

Herein, we demonstrated that a novel derivative of zeolitic imidazolate framework (ZIF) obtained by direct fluorination (ZIF-67) is an efficient electrocatalyst for Oxygen Evolution Reaction (OER). The obtained catalyst showed the main phase of tetragonal CoF2 from the metal center and the nitrogen-doped carbon from the ligands of ZIF-67. The polyhedral morphology was well kept but with a more rough surface consisting of assembled nanoparticles. Due to the good conductivity and high polarity in the system, this electrocatalyst showed an overpotential of 294 mV required to yield 10 mA cm−2 with good stability.

This paper mainly studied the analytical solutions of three types of Van der Pol-Duffing equations. For a system with parametric excitation frequency, we knew that the ordinary homotopy analysis method would be unable to find the analytical solution. Thus, we primarily used the multi-frequency homotopy analysis method (MFHAM). First, the MFHAM was introduced, and the solution of the system was expressed by constructing auxiliary linear operators. Then, the method was applied to three specific systems. We compared the numerical solution obtained using the Runge–Kutta method with the analytical solution to verify the correctness of the latter. Periodic solutions, with and without time delay, were also compared under the same parameters. The results demonstrated that it was both effective and correct to use the MFHAM to find analytical solutions to Van der Pol-Duffing systems, which were classical systems. By comparison, the MFHAM proved to be effective for time delay systems.

The Erdao Songhua River provides drinking water for 16.82 million people; therefore, ensuring that the water quality adequate is of particular concern. In this study, an improved water pollution index (IWPI) and multiple statistical methods were employed to assess the overall water pollution situation and investigate spatiotemporal variations of seven physicochemical parameters such as the permanganate index (PI), dissolved oxygen (DO), chemical oxygen demand (CODcr), five-day biochemical oxygen demand (BOD5), total nitrogen (TN), total phosphorus (TP) and ammonia nitrogen (NH3-N), which were collected monthly at 20 sites within the mainstream and major tributaries of the Erdao Songhua River Basin (ESRB) from 2015 to 2020. Stepwise regression analysis was conducted to build a minimum improved water pollution index (IWPImin) model consisted of four key elements (PI, DO, CODcr, and BOD5) proposed from seven parameters. The results demonstrated water quality within the ESRB was considered to be “Good” with the mean IWPI values

The aim of this study was to investigate the optimum time for γ-aminobutyric acid (GABA) application to improve the yield and quality in fragrant rice. Pot and field experiments were conducted during 2016–17 with two fragrant rice cultivars (for pot experiment), and five fragrant rice cultivars (for field experiment) which were applied with five GABA levels i.e. no GABA application (CK), application of GABA at 250 mg l−1 with 25 ml pot−1 at tillering stage (S1), panicle initiation stage (S2), heading stage (S3), and at tillering, panicle initiation and heading stages (S4) in the pot experiment. Similarly, the same treatments with 100 ml m−2 were applied to all rice cultivars in the field experiment. The S3 treatment significantly increased the 2-acetyl-1-pyrroline (2AP) contents in Meixiangzhan2 (14.76%) and Yuxiangyouzhan (20.19%) in pot experiment, Meixiangzhan2 (27.27%), Yuxiangyouzhan (40.24%), Basmati (43.07%) and Yungengyou14 (13.66%) in field experiment owing to regulations in the contents of proline, Δ1-pyrroline-5-carboxylic acid (P5C), GABA and the activities of enzymes involved in 2AP formation. The GABA treatments improved yield and modulated the antioxidant enzyme activities. This study provides a reference for the GABA application to improve yield and quality in fragrant rice.

The air-cooled motor controller has been widely used in electric aircraft due to its simple heat dissipation structure and maintenance-free features. Being the main heating component of the electric propulsion system of electric aircraft, the weight and the volume of the air-cooled motor controller need to be strictly controlled. Due to the short power running time of the electric motor controller, there is a large weight and volume allowance margin for the air-cooled radiator-based on the rated power and heat dissipation requirements of the motor controller.This paper proposes an air-cooled radiator design method that can reduce its volume and weight by optimizing its structure based on the operating conditions of the electric aircraft under the heat dissipation requirements.The structure of the air-cooled motor can be optimized by optimizing the structure the minimum structure of the motor controller radiator constrained by the maximum temperature of the Insulated Gate Bipolar Transistor (IGBT) module,which can be determined using an algorithm called the motor controller thermal resistance network model. Experimental results obtained from a prototype test on a two-seat electric aircraft demonstrate the effectiveness of the optimization method. The air-cooled radiator designed using the proposed method can be reduced by 5% in weight while meeting the heat dissipation requirements of the motor controller of the electric aircraft.

With the rising popularity of social networks and service recommendations, research on new methods of friend recommendation have become a key topic, especially when based on quality-driven resource processing in an edge computing environment. Traditional methods seldom systematically combine static attributes (e.g., interests, geographical locations, and common friends), dynamic behaviors (e.g., liking, making comments, forwarding and @), and network structures (e.g., social ties) to recommend a new friend to a target user. Meanwhile, with the advent of deep learning, it has become more challenging to integrate these features into a deep neural network framework for friend recommendation. For example, how do we optimally make use of these features to form a united framework and what type of deep neural network architecture should be introduced into a novel recommendation method in an edge computing environment? In this paper, we propose DFRec++, a hybrid deep neural network framework combining attribute attention and network embeddings to make social friend recommendations with the help of both interactive semantics and contextual enhancement. More specifically, we first utilize the latent dirichlet allocation (LDA) topic model to generate common interest topics between users and compute the similarity of the explicit static attribute vector representation of topics, locations, and common friends. Then we feed dynamic behavior attributes into a convolutional neural network (CNN) to obtain the implicit vector representation of the interactions and context between two users. Subsequently, a multi-attention mechanism is designed to further improve the deep vector representation of the attribute information. Next, the LINE-based network embeddings algorithm is applied to embed the network structure into a low-dimensional vector. Finally, the attribute attention vector and the network embeddings are concatenated to form a deep feature representation, which is subsequently fed to a fully connected neural network (FCNN) to capture the probability of friendship between two users. The output of FCNN indicates the probability of two users becoming friends. We conducted experiments on a real-world Weibo dataset and the results show that DFRec++ outperforms several existing methods.

Summary: Conventional printing is worth revisiting because of its established procedures in meeting the surging demand of manufacturing printed electronics, 3D products, etc. However, one goal in penetrating printing into these is to control pattern transfer with no limitation of wettability. Here we introduce a miscible liquid-liquid transfer printing mechanism that can synchronize material preparation and material patterning with desirable properties including limitless selection of raw materials, corrosion resistance, no wetting constraint, and ability to prepare large-area defect-free materials for multi-function applications. Theoretical modeling and experiments demonstrate that donor liquid could be used to make patterns within the bulk of a receiver material, allowing the obtained intrinsically patterned functional materials to be resistant to harsh conditions. Different from current liquid printing technologies, this printing approach enables stable and defect-free material preparation and is expected to prove useful in flexible display, soft electronics, 4D printing, and beyond. : Interface Science; Surface Property; Materials Property; Materials Design Subject Areas: Interface Science, Surface Property, Materials Property, Materials Design

The density of tar vapor and water vapor produced by coal pyrolysis is different. Different centrifugal forces will be generated when they flow through the hydrocyclone. The water vapor and tar vapor are divided into inner and outer layers. According to this phenomenon, the moisture in the tar can be removed. In this paper, a Eulerian gas–liquid two-phase flow model is established by numerical simulation to study the effect of inlet velocity on the separation effect of a designed hydrocyclone (split ratio 0.2). The results show that the inlet velocity and moisture content have an influence on the volume distribution characteristics, tangential velocity, axial velocity, pressure drop distribution, and separation efficiency of tar vapor and water vapor in the hydrocyclone. When the inlet velocity increases from 2.0 to 12.0 m/s, the central swirl intensity increases, and the negative pressure sweep range at the overflow outlet increases. The axial velocity increased from 2.8 to 14.9 m/s, tar vapor content at the overflow outlet decreased from 74% to 37%, and at the underflow outlet increased from 89% to 92%. When the moisture content is lower than 10%, the hydrocyclone with the split ratio of 0.20 is no longer suitable for the separation of oil–water two-phase vapor. However, when the water content is higher than 20%, the purity of tar vapor at the underflow outlet can reach 92%, and the overflow outlet needs multistage separation to realize tar purification.

Rock burst has become one of the most serious world’s problems in coal resources mining, and fracture and movement of thick and hard strata in high position is the main reason to induce strong mining earthquake and rock burst. Multicoal seam mining of 10302 working face in Baodian coal mine is selected as an engineering background, which has thick and hard strata in high position. Using SOS microseismic monitoring system to collect microseismic events and date during multicoal seam mining, characteristic and difference of microseismic in multicoal seam mining under thick and hard rock in high position is analyzed systematically. The main research work is as follows: reveal temporal and spatial distribution and evolution law of microseismic and analyze difference and correlation of microseismic in multicoal mining under thick and hard strata in high position, especially the relationship between mining earthquake with high energy and fracture and movement of thick and hard strata in high position. With the characteristics of microseismic, rock burst mechanism and difference induced by thick and hard strata in high position are discussed. The research and achievement could make guidance to multicoal seam mining safety under thick and hard strata in high position.

In order to improve the pronunciation accuracy of spoken English reading, this paper combines artificial intelligence technology to construct a correction model of the spoken pronunciation accuracy of AI virtual English reading. Moreover, this paper analyzes the process of speech synthesis with intelligent speech technology, proposes a statistical parametric speech based on hidden Markov chains, and improves the system algorithm to make it an intelligent algorithm that meets the requirements of the correction system of spoken pronunciation accuracy of AI virtual English reading. Finally, this paper combines the simulation research to analyze the English reading, spoken pronunciation, and pronunciation correction of the intelligent system. From the experimental research results, the correction system of spoken pronunciation accuracy of AI virtual English reading proposed in this paper basically meets the basic needs of this paper to build a system.

Four spirobichroman-based polyimides (6FDA-F, 6FDA-O, 6FDA-P, and 6FDA-M) were successfully obtained via polyreaction between diamines of different substituents (-H, -OCH3, -N, and -CH3) and 4,4′-(hexafluoroisopropylidene)-diphthalic anhydride (6FDA). The molecular weights, thermophysical, dihedral angle of the molecules, fractional free volume, d-spacing, Brunauer–Emmett–Teller surface area, and gas separation performance were studied through a combination of experiments and molecular dynamics simulations. These polymers show high molecular weights, with number-average molecular weights (Mn) in the range of 5.0–15.3 × 104, and excellent thermal stability, with weight loss temperatures (T5%) of over 420 °C. The pure-gas (O2, N2, CO2, and CH4) permeation results indicated that the four polymers selectivity of CO2/CH4 over 31 and that 6FDA-F had the highest gas permeability among the four tested gases. Importantly, the dihedral angle from molecular simulation was used to clarify the phenomenon wherein the 6FDA-P gas permeability lower than 6FDA-F. A detailed analysis indicates that -CH3 increased the gas permeability of the polyimides, while the turnstile-like rotary thermal motion of -OCH3 formed channel obstacles and improved the gas selectivity. The polymers containing pyridine ring and those containing benzene ring follows different gas separation mechanisms, based on the gas solution-diffusion behaviour.

As a key component of electric aircrafts, electric propulsion systems provide sufficient thrust for electric aircrafts. By improving its efficiency, the power consumed by the electric propulsion system can be reduced. Therefore, the maximum range of electric aircrafts, which is limited by the energy density of batteries, can be further increased. Upon investigating the power demand and the energy consumption of the electric propulsion system in each flight profile phase of fixed pitch propellers electric aircrafts, this paper proposes a novel energy efficiency optimization method tailored for fixed pitch propeller electric aircrafts by minimizing the total energy consumption of one flight over the maximum efficiency of the propeller. The proposed method is adopted to the design of a fixed pitch propeller electric aircraft. Experimental results suggest that the tested fixed propeller electric aircraft designed can achieve better energy efficiency while reducing energy consumption by more than 10%.

Abstract Late gadolinium enhancement (LGE) imaging is the currently the gold standard for in-vivo detection of myocardial infarction. However, gadolinium contrast administration is contraindicated in patients with renal insufficiency. We aim to evaluate the diagnostic sensitivity and specificity of this contrast-free MRI technique, native T1 mapping, in detecting recent myocardial infarction versus a reference histological gold standard. Ten pigs underwent CMR at 2 weeks after induced MI. The infarct size and transmural extent of MI was calculated using native T1 maps and LGE images. Histological validation was performed using triphenyl tetrazolium chloride (TTC) staining in the corresponding ex-vivo slices. The infarct size and transmural extent of myocardial infarction assessed by T1 mapping correlated well with that assessed by LGE and TTC images. Using TTC staining as the reference, T1 mapping demonstrated underestimation of infarct size and transmural extent of infarction. Additionally, there was a slight but not significant difference found in the diagnostic performance between the native T1 maps and LGE images for the location of MI. Our study shows that native T1 mapping is feasible alternative method to the LGE technique for the assessment of the size, transmural extent, and location of MI in patients who cannot receive gadolinium contrast.

Abstract Purpose The existence of positive solutions for a class of nonlinear Schrödinger-Kirchhoff-Poisson systems. Methods Variational method. Results Some results on the existence of positive solutions.

Pipeline leak detection has always been a relatively difficult technical problem; especially in urban pipeline leak detection, there are still many problems to be solved. A multipoint leak detection and location method for urban gas pipelines based on variational mode decomposition and relative entropy was proposed. Firstly, the experiment pipeline system was built, and the original signal was collected by acoustic emission technology; then, a variational model method was used to decompose the signal to obtain multiple intrinsic mode function (IMF) components with different characteristic scales. According to the characteristics of relative entropy, each component was analyzed, the appropriate IMF component was selected, and the selected component was reconstructed to obtain the observation signal. The multipoint leakage location model of the urban gas pipeline was established. The number of source signals was estimated by singular value decomposition, and the leakage signals were separated; finally, the accurate location of leakage point was achieved by cross-correlation positioning. The results showed that the average relative error of the pipeline leak location results is 2.97%, and the leak location accuracy is significantly improved, achieving the purpose of precise location.