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Ferroelectric electrocaloric (EC) materials represent a promising alternative for environment-friendly cooling technologies to replace vapor-compression-based refrigeration. The general strategy is to construct the relaxor phase transition around room temperature (RT) to improve the EC effect and expand its operating temperature. However, this strategy sacrifices the inherent EC response of ferroelectrics and needs a high excitation electric field (ΔE). Guided by the physical origin of the EC effect in ferroelectrics, we designed a lead-free BaTiO3-based ceramic to realize the close, successive ferroelectric–ferroelectric and ferroelectric–paraelectric (FP) transitions, which induce a broad metastable-phase-transition region near RT. In this ceramic, the ferroelectric polar matrix and reduced energy barriers greatly facilitate the polarization rotation/reversion, maintaining the strong ferroelectric polarization but large polarization change in a wide temperature range. We achieved a large EC coefficient ΔT/ΔE of >0.3–0.35 K mm kV−1 at a small ΔE of 5–15 kV cm−1, and a high temperature change ΔT of >0.9 K (40 kV cm−1). More importantly, our system exhibits a broad temperature span of a large EC effect, which greatly exceeds the performance of previous BaTiO3-based reports employing single FP relaxor transition, even twice wider than that of them. This work offers a new general solution to design EC materials with superior performances for practical EC cooling applications.

Electrostrictors offer unique advantages over piezoelectrics, including no poling process, temperature stability and hysteresis-free strain characteristics. Learning from the distinction between disordered and ordered ABI0.5BII0.5O3 perovskite-structured electrostrictors, the electrostrictive effect enhances with a smaller active space for B ions. Here, we propose a novel design strategy to arouse the potential capacity of electrostriction in BaTiO3-based materials by A-site Li+–Ho3+ ion-pairs engineering. In this way, limited active space for a Ti-site is expected due to the contracted oxygen octahedron around ion-pairs, resulting in smaller polarization per unit magnitude of electric field but a larger strain per unit magnitude of polarization and therefore an enhanced longitudinal electrostrictive coefficient Q33. A systematic analysis evidenced that Li+ and Ho3+ ions tend to occupy the neighboring Ba-sites in one unit cell of BaTiO3, and directly form Li+–Ho3+ ion-pairs along the [001] direction. Besides, partial fragmented domain patterns induced by local structural heterogeneity due to the involvement of ion-pairs are detected in samples with higher dopants, benefiting suppression of hysteresis in strain curves. Consequently, the (Li, Ho) co-doped BaTiO3 ceramics by A-site engineering exhibit giant Q33 up to 0.06 m4 C−2 which is superior to other lead-bearing/free electrostrictive materials, meeting the requirement of a thermal stability (20–150 °C) – low hysteresis (

For perovskite ferroelectric oxides, the composition-induced transition from ferroelectrics to relaxors can enhance their electrostrictive coefficient Q33 remarkably, and has been attracting more and more attention in recent years. Achieving a larger electro-strain response is one of the most original driving forces for pursuing higher Q33 values, while the two are often incompatible. Herein, taking the promising relaxor ferroelectric Na0.5Bi0.5TiO3 (NBT) as the research object, we report the excellent electrostriction-like electro-strain behaviors (0.41% ≤ Suni ≤ 0.46%, 25 ≤ T ≤ 125 °C; Suni exhibits only 2.23% decline after 105 cycles) together with a series of enhanced Q33 values (0.029–0.047 m4 C−2). Accompanied by the reconstruction of de-coupled A–O interactions, the electric-field-induced relaxor to ferroelectric state transition contributes to the superior electro-strain behaviors, while the enhanced Q33 will greatly degenerate during this transition process. In contrast to the non-hysteretic electrostriction observed in linear dielectrics, for NBT-based relaxor ferroelectrics, the peculiar coexistence of ferroelectric in-phase a0a0c+ and anti-phase a−a−a− tiltings is suggested to contribute to the enhanced electrostriction-like behaviors observed in this work. These observations indicate that NBT-based systems can be considered as a potential family of peculiar lead-free electrostrictors for application in the field of actuators.

Catalyst deactivation by coking and sintering over Ni-based catalysts is still an open question for carbon dioxide reforming of methane (CDRM). Here, Ni/MoCeZr/MgAl 2 O 4 -MgO complex support catalysts were successfully synthesized by calcination of the Ce, Zr and Mo promoted NiMgAl-hydrotalcite-like precursors using a simple one-step co-precipitation method. Particular attention was paid to the anti-coking properties and catalytic behaviors of these complex support catalysts prepared at different calcination temperatures (700, 800 and 900 °C). Under harsh conditions (at 900 °C under GHSV of 60,000 mL·h −1 ·g cat −1 and without using inert gases as diluents), the catalyst calcined at 800 °C yielded a high conversion of CH 4 and CO 2 above 95% and long-term stability for 658 h without any remarkable coke deposition (only 0.015 mg C ·h −1 ·g cat −1 ), outperforming the catalysts obtained at other calcination temperatures. Coking analysis showed that all the catalysts generated negligible coke deposition, indicating that solving the coke deposition problem puzzled researchers for many years is possible. Further analysis revealed that the generation of small Ni nanoparticles (

To investigate the usefulness of carotid contrast-enhanced ultrasound (CEUS) in assessment of disease activity in patients with Takayasu arteritis (TA).After screening 219 CEUS records from 124 consecutive patients followed at our clinic between October 2014 and May 2018, data were analysed from 159 carotid CEUS from 86 patients diagnosed with Type I TA. Patients were categorized based on disease activity according to National Institutes of Health criteria into two groups: active disease group (92 CEUS) and non-active disease group (67 CEUS). The enhanced intensity of carotid artery wall: (i) was higher in active disease group than in non-active disease group (3.09 ± 1.67 dB vs. 1.44 ± 1.29 dB, P 0.0001, respectively); and (ii) had a high predictive value for TA disease activity with area under the curve (AUC) of 86.3% [95% confidence interval (CI) 79.7-92.9], sensitivity of 88.0%, and specificity of 79.1%. The latter AUC was not significantly affected (P 0.05) when erythrocyte sedimentation rate, C-reactive protein level, or arterial wall thickness were added to assessment of disease activity in TA.Carotid vascularization by CEUS, as sole inflammatory marker, had a high predictive value for disease activity in Type I TA.

Background. The study was to analyze the clinical manifestation variety and management choices of symptomatic Meckel’s diverticulum in children. Methods. From July 2008 to October 2018, 28 cases of Meckel’s diverticulum with a variety of complications were admitted to our hospital. The clinical data included age, gender, symptoms and signs, investigations, intraoperative and pathological findings, and outcome. Results. The ratio of males to females was 2.5 : 1. The diagnoses were made by 99mTc-pertechnetate scan (in 5 cases) and by exploratory laparotomy (in 2 cases). The initial diagnosis in the other cases includes intussusception (in 4 cases), acute appendicitis (in 5 cases), intestinal obstruction (unknown origin), peritonitis, and even shock in 12 cases. Laparoscopic surgery was performed in 8 cases; 18 cases underwent open surgery. Excision of partial bowel segment with diverticulum and primary anastomosis was done in 22 cases and wedge resection of diverticulum in 4 cases. Two other cases received nonoperative therapy and went to other hospitals to receive surgical management. Ectopic gastric mucosa in the diverticulum was found in 9 cases, including 6 cases with lower gastrointestinal bleeding. Conclusion. The clinical characteristics of Meckel’s diverticulum varied. Children with hematochezia, peritonitis, and intestinal obstruction without history of prior abdominal operation should be suspected with this disease until proven otherwise. Hematochezia is often associated with ectopic gastric mucosa in the diverticulum. Laparoscopic surgery should be one of the choices for the diagnosis and treatment of Meckel’s diverticulum with complications.

This article studies the uniqueness of wave speeds of traveling wave solutions in bistable reaction–diffusion equations, in which the degenerate condition at steady states is admissible and the diffusion operator may be the Laplacian, discrete lattice or integral form. By upper and lower solutions method, we prove the uniqueness of wave speeds and strict monotonicity of traveling wave solutions.

In the eastern mining area of Ningxia, China, multi-layered sandstone aquifers are widely distributed in the underground. However, the water abundance of these aquifers is not clear, which brings great challenges to the prevention and control of mine water disaster. In this paper, five mining areas in eastern Ningxia were taken as the study area, and the distribution characteristics of aquifer and the mine water filling source were analyzed through the analysis of geological data and numerical simulation. Finally, the lithology influencing index (LII) was constructed, and the water abundance of the aquifer was evaluated. The results show that the sandstone aquifer III in the lower part of the Jurassic Zhiluo formation is the main water-source aquifer of the #2 coal seam in the study area, while the middle aquifer II and the upper aquifer I are indirect water-source aquifers, the areas with extremely strong and strong water abundance are Maiduoshan, Hongliu, the south of Shicaocun, southeast and southwest of Meihuajing, and the central and southern areas of Shuangma mining areas, when the depth of water drainage boreholes in the roof reaches the development height of the water-conducting fracture zone, the pre-drainage measures can effectively control the mining inrush water of the working face and ensure the safety production. This research is of great significance to the prevention and control of mine water disaster.

To improve the resource recovery efficiency of mining face in thick coal seams, the correlation between deformation failure of bottom coal in the gob-side entry and coal pillar width was analyzed by theoretical analysis, numerical calculation, and similar simulation experiments. The results showed that, when the coal pillar was strong, with the decrease of pillar width, the failure depth of the bottom coal in the gob-side entry and floor heave increased. The deformation failure depth of the bottom coal in the entry was inversely related to the width of the coal pillar. The bottom coal was further fractured and dispersed under the action of tension, shear, and extrusion in the process of floor heave. Based on the floor heave induced by the narrow coal pillar, a recovery technique of the bottom coal with thick coal seams in the gob-side entry was developed. The width of the narrow pillar to be reserved was obtained by theoretical calculation and revised by numerical simulation, ultimately, the reasonable width was determined. Under the complex stress of the narrow pillar, the bottom coal in the gob-side entry was fully heaved, cracked, and separated. To realize the comprehensive mechanization and resource recovery of bottom coal, a matching mining excavator loader, transfer conveyor, and retractable belt conveyor were selected to transport the crushed bottom coal in the entry. This method has been successfully applied to the return airway of working face 8407 in the No. 5 Coal Mine of Yangquan Coal Group with remarkable economic and social benefits.

Electromechanical actuators with toxic lead-based electrostrictive materials dominate the market of high-precision electronics devices, so one of urgent aims becomes how to explore the new generation of ecofriendly electrostrictive materials with superior electrostriction behaviors. Herein, a strategy of modifying the active space for the B-site in lead-free relaxor ferroelectrics arouses the potential capacity of electrostriction, including K

The crushed gangue materials which are filled into the goaf in solid-backfilling coal mining become the main body of bearing the overburden after the tamping process. Its resistance to deformation is the key to control overburden movement and surface subsidence. Particle breakage affects the resistance to deformation of filling materials. In this paper, a confined compression test of crushed gangue under different loading rates was designed, and the acoustic emission (AE) signal was monitored in the process of confined compression. The test results showed that with the increase of loading rate, the anti-deformation ability of crushed gangue showed a dynamic change process of increasing, decreasing, and then increasing again. With the increase of loading rate, the breakage degree of the samples decreased, the proportion of large-sized gangue increased, the growth period of AE counts showed an obvious hysteresis phenomenon, and the AE activity level of the gangue increased gradually. The research results can not only provide a more in-depth and comprehensive understanding of the mechanical properties of crushed gangue filling materials but also provide a reference for the engineering application of solid-filling coal mining.

Lead-free relaxor ferroelectrics (RFEs) exhibit a broader variety of phenomena in comparison with the "canonical" lead-containing compositions, rendering them attractive for newly multifunctional materials with low-cost and eco-friendly processing. Here, guided by the characteristics of relaxor ferroelectrics, lead-free (1

In this study, we investigated the protective effects of gastrodin (Gas) against homocysteine‐induced human umbilical vein endothelial cell (HUVEC) injury and the role of the phosphoinositide 3‐kinase (PI3K)/threonine kinase 1 (Akt)/endothelial nitric oxide synthase (eNOS) and NF‐E2‐related factor 2 (Nrf2)/antioxidant response element (ARE) pathways. We stimulated cells with homocysteine (1 mmol/L, 24 hours) and tested the effects of gastrodin (200‐800 μg/mL) on cell viability and the production of malondialdehyde (MDA), lactate dehydrogenase (LDH) and reactive oxygen species (ROS). Then, Nrf2 distribution in the cytoplasm and nucleus as well as the expression of enzymes downstream of Nrf2 was determined. Furthermore, we analysed the expression of bax, bcl‐2 and cleaved caspase3, and assessed the involvement of the PI3K/Akt/eNOS pathway by Western blots. Finally, we tested the vasoactive effect of gastrodin in thoracic aortic rings. The results showed that gastrodin decreased MDA, LDH and ROS production and increased cell viability, NO production and relaxation of thoracic aortic rings. Moreover, the protective effects of Gas on NO production and relaxation of thoracic aortic rings were blocked by L‐NAME but enhanced by Cav‐1 knockdown, and MK‐2206 treatment abolished the effect of Gas on the ROS. In addition, treatment with gastrodin increased Nrf2 nuclear translocation, thus enhancing the expression of downstream enzymes. Finally, gastrodin increased the expression of PI3K, p‐Akt, and eNOS and decreased Cav‐1 protein expression. In conclusion, our study suggested that gastrodin may protect HUVECs from homocysteine‐induced injury, and the PI3K/Akt/eNOS and Nrf2/ARE pathways may be responsible for the efficacy of gastrodin.

Background: The Health Commission of Wuhou reformed its primary care system by implementing a Transformative Learning Collaborative (TLC): a structure that supports shared learning and rapid change among a group of providers or organisations. This paper examines the adaptation of a district TLC to implement, disseminate, and scale up the principles of a District Model for family doctor teams and managers of Community Health Centres (CHCs) in China. We describe TLC as a means of informing training content and evaluated the implementation through participant feedback. Methods: A district TLC was implemented to disseminate a District Model, which included six quality improvement principles and was developed to reform the primary care delivery process. Family doctor teams (n=26, 52 family doctor individuals) and managers (n=13) from thirteen CHCs in a Chinese district participated in the TLC organisation. The TLC process was described, and survey data served to assess the activities and resource usefulness. The perceived implementation enablers and inhibitors were also descriptively analysed. Results: The purpose, content, and process of TLC were described. The implementation included four steps: structure establishment, participants identification, activities implementation, and setting up a feedback system. The survey findings captured family doctors’ and managers’ feedback with regard to preference, needs, concerns, and problems in implementing TLC training. In general, most family doctors and managers indicated that TLC was necessary. All the successfully implemented Plan-Do-Study-Action cycles (77.6%) were applied to the model. Family doctors and managers agreed that coaches, a programme director, and data analysts were useful resources. The top three enablers for successful TLC implementation were managers’ support (93.9%); improvements in self-ability and team-based ability and impacts on participants’ career goals (89.8%), and support from family doctor teams (87.8%). Conclusions: This study offered a guided process for running TLC in the primary care system of China and provided valuable feedback from family doctors and managers regarding TLC training. Challenges were also found for future research and consideration. Our findings suggest that manager support is necessary for collaboration in family doctor teams and that participants play an important role by evaluating learning sessions and providing recommendations for future learning.

Quantitative real-time PCR (qPCR) has become a widely used approach to analyze the expression level of selected genes. However, owing to variations in cell types and drug treatments, a suitable reference gene should be selected according to special experimental design. In this study, we investigated the expression level of ten candidate reference genes in hepatoma carcinoma cell (HepG2) and human hepatocyte cell line (L02) treated with ethanol (EtOH), hydrogen peroxide (H2O2), acetaminophen (APAP), and carbon tetrachloride (CCl4), respectively. To analyze raw cycle threshold values (Cp values) from qPCR run, three reference gene validation programs, including Bestkeeper, geNorm, and NormFinder, were used to evaluate the stability of ten candidate reference genes. The results showed that TATA-box binding protein (TBP) and tubulin beta 2a (TUBB2a) presented the highest stability for normalization under different treatments and were regarded as the most suitable reference genes of HepG2 and L02. In addition, this study not only identified the most stable reference genes of each treatment, but also suggested that β-actin (ACTB), glyceraldehade-3-phosphate dehydrogenase (GAPDH), tyrosine 3-monooxygenase/tryptophan 5-monooxygenase activation protein zeta (YWHAZ), and beta-2 microglobulin (B2M) were the least stable reference genes in HepG2 and L02. This work was the first report to systematically explore the stability of reference genes in injured models of HepG2 and L02.

Carbon deposition is a major bottleneck for the development of durable catalysts applicable for the dry reforming of CH4 (DRM). In this work, the carbon deposition behaviors in dry reforming of CH4 at elevated pressures over Ni/MoCeZr/MgAl2O4-MgO catalysts which exhibited a durable stability and excellent coking resistance at atmospheric pressure DRM reaction in our previous report were examined. The differences in the types and sources of carbon deposition under atmospheric pressure and elevated pressure were clarified by XRD, TPO, TEM and Raman spectroscopy as well as the comparative experiments conducted in CH4, CO and CH4/CO atmospheres. It was found that the stability of the catalyst declined rapidly at elevated reaction pressure, and the sources and types of carbon deposition in DRM reaction under atmospheric pressure and pressurized conditions were significantly different at temperatures above 800 °C, but barely differed at temperatures below 700 °C. Under atmospheric pressure, the filamentous carbon (carbon nanotubes, CNTs) was produced by CH4 decomposition reaction and CO disproportionation reaction at 500 and 600 °C, the encapsulated graphitic carbon was generated by CH4 decomposition reaction at 800 and 850 °C, and the filamentous carbon and encapsulated graphitic carbon deriving from CH4 decomposition reaction and CO disproportionation reaction coexisted at 700 °C. Under high pressure, CH4 decomposition reaction and CO disproportionation reaction were jointly involved in the formation of carbon deposition. The filamentous carbon was formed regardless of the reaction temperature, and accompanied by the encapsulated graphitic carbon at 700, 800 and 850 °C. It is concluded that stable DRM catalysts at atmospheric pressure may not be competent for the pressurized DRM because the sources and types of carbon deposition at pressurized conditions are different and the methods of carbon removal and suppression at atmospheric pressure are not fully applicable, thus further study is needed to develop durable catalysts at pressurized DRM.

Upon the observation, small patches near the bottom of the vacuum container are found perforated in some situations, which severely affect the work efficiency and safety of the system. To investigate the mechanism of the damaging perforation, in this paper, a numerical method based on Fluent software is implemented to simulate wall shear stresses of the vacuum container. It is shown that the numerical method implemented accurately captures the flow pattern and the wall shear force distributions during the operation of the vacuum container. With such a simulation approach, the area prone to perforation can be effectively yet clearly identified and predicted. The wall shear stresses of the vacuum container are closely correlated with the inlet velocity. It is demonstrated that the wall shear stresses of the vacuum container tends to increase in magnitude with the increase of the inlet velocity.

In this work, three-dimensional (3D) amine-terminated ionic liquid (IL) covalently functionalized graphene/Pd composite aerogels are successfully fabricated via a facile and green reduction-inducing self-assembly method. The morphology and composition of the obtained 3D IL-rGO/Pd composite aerogels are studied by means of TEM, SEM, XRD, FTIR, XPS, BET, and Raman spectroscopy. In those composites, the cations of NH2-IL introduced to the surface of graphene sheets can avoid the restacking of graphene sheets and enlarge the specific surface area, which provide efficient transport pathways for improving the catalytic performance. The negatively charged Pd precursors (PdCl42−) are adsorbed on positively charged imidazolium ring moiety of NH2-IL to engender Pd NPs with small particle sizes uniformly distributed on the graphene sheets, which can maximize the active surface area of catalysts and enhance their catalytic activity. The catalytic studies show that the 3D IL-rGO/Pd composite aerogels can be used as efficient, easy separation, recyclable, and stable catalysts for the Suzuki cross-coupling reactions under mild conditions, and the catalytic efficiency shows no obvious loss even after ten repeated cycles.

The discharge of ship ballast water (containing large amounts of alien organisms) has caused severe ecological hazards to marine environments. In this study, three metal elements (Ag, Fe, and Gd) were doped to nano-TiO2 material respectively (content: 0.4%, 0.7%, and 1.0%) to improve inactivation effect of Escherichia coli and Enterococci in ballast water. Experimental results indicate that compared with the sole ultraviolet (UV) and the UV and original nano-TiO2, the UV and metal-doped nano-TiO2 increased the bacterial inactivation rate to different extents. For each metal element, high external metal content (1.0%) corresponded to high inactivation effort. The doping of Ag resulted in optimal inactivation effort, and the addition of Fe and Gd caused unobvious effort. At the end of the inactivation process (20 s), the UV and 1% Ag-doped nano-TiO2 reached the highest logarithmic sterilization rates (0.915 for Escherichia coli and 0.805 for Enterococcus). The doping of Ag, Fe, and Gd did not change the anatase phase TiO2 crystal form, and 1% Ag-doped nano-TiO2 had the smallest particle diameter and the evenest distribution of nanoparticles. Compared with the sole UV, the UV and Ag-doped nano-TiO2 treatment resulted in higher malondialdehyde contents (0.0646 μmol/L for Escherichia coli and 0.0529 μmol/L for Enterococci) and lower superoxide dismutase activities (0.672 U/mL for Escherichia coli and 0.792 U/mL for Enterococci), which were in accordance with high inactivation rates in these cases.

The underground reservoir of a coal mine can store and purify mine water. The high salinity ions in the underground reservoir of a coal mine can be removed by the adsorption with gangue block, and the high salinity mine water can be purified in the flow process of the underground reservoir of a coal mine. Through the dynamic leaching experiments, the effects of gangue gradation, ion concentration and ion sort of displacement fluid on the dynamic adsorption characteristics of gangue were studied, the leaching laws of Ca2+, K+, Mg2+ ions were obtained. The results show that (1) the smaller the average particle size of the gangue in the leaching column, the better the adsorption effect of the leaching column on Ca2+, the higher the removal rate of Ca2+. (2) Mg2+ has a relatively strong promoting effect on the dissolution of K+ and Ca2+, and K+ also has a relatively strong promoting effect on the dissolution of Mg2+. (3) The higher the concentration of Ca2+ in the displacement fluid, the more significant the promoting effect of Ca2+ on the dissolution of Mg2+ and K+, and the greater the dissolution mass of Mg2+ and K+ in unit time. (4) There are two different types of adsorption sites for Ca2+ on the surface of gangue. When the concentration is low, Ca2+ is adsorbed by the first adsorption site. When the concentration is high, Ca2+ is adsorbed by the second adsorption site. The research results can provide theoretical reference and data support for the in-depth understanding of the water purification mechanism and engineering design of underground reservoir in a coal mine.

Ultrasonic driven wireless charging technology has recently gained increasing attention. High-performance potassium sodium niobate [(K, Na)NbO3, KNN] based ceramics and its potential application on energy harvesting device are presented in this work. A series of lead-free 0.964(K0.48Na0.52)Nb0.96Sb0.04O3-0.032(Bi0.5Na0.5)ZrO3-xBiFe0.9Co0.1O3 [KNNS-BNZ-xBFC] piezo-ceramics are first designed and prepared to search for good piezoelectric properties, high Curie temperature and good thermal stability. Through content tailoring, the KNNS-BNZ-0.004BFC ceramic presents enhanced piezoelectric properties via the construction of rhombohedral-tetragonal phase boundary near room temperature. Based on the synthesized ceramics, a high-output flexible ultrasound-based wireless energy harvesting device is further designed and manufactured to establish a connection among ceramics and practical application in lead-free KNN-based ceramics. The average ultrasound receiving sensitivity of the fabricated device is calculated to be ~ 1.5 Vpp·MPa−1, demonstrating the superior performances. An instantaneous power density of 52.07 mW/cm2 has been obtained from the incident ultrasound pressure of 1.90 MPa. Capacitor charging applications and the feasibility study of ex vivo characterizations under porcine tissue also demonstrate the good application prospect of the harvester. The above results exhibit great potential of the environmentally friendly KNN-based materials to be integrated in the implantable device for safe biomedical applications.

In this work, the multiphase coexistence of rhombohedral-orthorhombic and orthorhombic-tetragonal (R-O/O-T) was constructed in (1-x-y)BaTiO3-xCaTiO3-yBaZrO3 ceramics with 0.14 ≤ x ≤ 0.16 and 0.10 ≤ y ≤ 0.12, and thus a large piezoelectric constant (d33) of 600 pC/N was attained in the ternary (1-x-y)BaTiO3-xCaTiO3-yBaZrO3 ceramics using the optimization of x and y. The R-O/O-T multiphase coexistence as well as the enhancement of dielectric and ferroelectric properties can be responsible for the high d33 of this work. In addition, a high strain of 0.15% was observed in the multiphase coexistence. As a result, electrical properties of BaTiO3 can be optimized by the construction of multiphase coexistence through the co-doping of CaTiO3 and BaZrO3.

This paper describes the numerical research that studied the macroscopic mechanical behavior and the microscopic particle movement of gangue with different gradation under different confining condition and loading rate. Two types of compression tests, confined compression tests and triaxial compression tests were simulated using the commercial numerical modeling software PFC 3D . Most of the gangues are irregular convex polyhedron in shape. When under compression, huge contact force can be generated between particles result in interlocking effect. In order to reproduce the interaction between gangues, this research used Clump Template tool in PFC 3D to generate clusters of particles to represent tailing particles. Following observations were made based on numerical modeling result: 1) reasonable particle gradation can significantly improve the anti-deformation capacity and decrease lateral stress coefficient of gangue. 2) In triaxial compression tests, the load bearing capacity of gangue increases with the increase of confining pressure. 3) Distribution of particles axial displacement showed ‘horizontal layering’ feature in confined compression tests, and showed ‘concave layering’ feature in triaxial compression tests. In triaxial compression tests, particles close to the mid-height and the sides of the sample have most significant lateral displacement, forming a triangular zone of significant lateral displacement. It is also found that smaller particles move more actively while the large particles have their own “movement inertia”. 4) With the increase of confining pressure, the number of the contact force chains and the maximum contact force between particles within the sample increases gradually, also the interpenetration degree of the contact force chains gradually increased. Meanwhile, the number of contact force chains and the maximum contact force are comparatively higher by using confined compression condition than the confining pressure at the same stress state. 5) Large size gangue particles play the main role in anti-deformation and transfer of axial stress; the surface contact force of large particles is significantly greater than that of the small particles. 6) Faster loading rate may increase the measured load bearing capacity of the gangue sample under the same confining condition.

Here we demonstrated two different hydrothermal methods for synthesizing Fe3O4/CoSe2 hybrids with different weight ratios of Fe3O4 and CoSe2. The synthesized materials were characterized by scanning electron microscopy, transmission electron microscopy, X-ray diffraction and X-ray photoelectron spectroscopy. And the electrochemical properties were obtained by linear sweep voltammetry, chronoamperometry and electrochemical impedance spectroscopy. For the first method, the obtained catalyst with loading 20% Fe3O4 on CoSe2 (C20a) exhibits the highest oxygen reduction reaction activity. While for the second method, the obtained catalyst with loading 30% Fe3O4 on CoSe2 (C30b) exhibits the highest oxygen reduction reaction activity, with an onset potential of 0.775 V, a half-wave potential of 0.600 V, and Tafel slope of 65 mV decade−1 in O2-saturated 0.5 M H2SO4. Which are better than those of C20a (0.753, 0.567 V and 67 mV decade−1), CoSe2 (0.708, 0.560 V and 66 mV decade−1) and Fe3O4 (0.700, 0.556 V and 79 mV decade−1). More importantly, C30b shows much higher stability and better methanol, ethanol and ethylene glycol tolerance than other prepared materials.

To analyze the influence of movement in shallow-buried working faces with large mining heights on mine pressure manifestation, the key stratum at a working face was categorised using the 1313 top-coal caving face with super great mining height under cover as a case study. The research combined theoretical analysis, field measurement, and numerical simulation to analyze the influencing mechanism of key stratum. Moreover, the research results were verified by numerical simulation and indicate that the sub-key stratum is prone to be broken to form a “cantilever beam” structure rather than a stable hinged structure during the excavation of working faces with super great mining heights. When the “cantilever beam” structure is unstable, a low pressure will occur on the working face, and the overlying strata will subside simultaneously with the sub-key stratum to induce the breakage of the primary key stratum: the breakage will further trigger the periodic breakage of sub-key stratum, causing a greater load on the working face. Finally, steps, and strength of weighting in the working face vary to be great or small alternatively. This is the main reason explaining why the 1313 working face shows strong mine pressure manifestation. The results provide theoretical and practical experience for forecasting and controlling mine pressure manifestation.

To settle the drawbacks of non-cost-effective and enhance the electrocatalytic performance of Pt/C, Fe@Pt core-shell nanoparticles supported by Vulcan XC-72 have been designed and synthetized successfully. The synthesized materials were characterized by X-ray diffraction, scanning electron microscopy, transmission electron microscopy, and X-ray photoelectron spectroscopy, whereas the electrochemical analyses were obtained by electrochemical impedance spectroscopy, cyclic voltammetry, linear sweep voltammetry, and chronoamperometry. Results suggest that the onset potential of oxygen reduction reaction on the Fe@Pt/C is about 0.6 V (vs. Hg/Hg2Cl2) in O2-saturated 0.5 M H2SO4, which shifts positively more than 30 mV compared with that of Pt/C. The corresponding electron transfer number is 4, meaning the reduction reaction mainly occurred through a 4-electron pathway. More importantly, the Fe@Pt/C has an excellent stability and better catalytic performance towards oxygen reduction reaction activity compared with Pt/C. Thus, Fe@Pt/C could be utilized as promising cathode catalysts in proton exchange membrane fuel cells.

The first total syntheses of 9-epoxyfalcarindiol 1a and its diastereomer 1b have been achieved. Central to our approach were the Zn-cyclopropane-based amino alcohol catalyzed enantioselective alkynylation of acrolein, the diastereoselective addition of a diynic ester to an epoxy aldehyde, and the asymmetric Sharpless epoxidation of allylic alcohol catalyzed with L-(+)-diethyl tartrate and Ti(OiPr)4.

The microstructure and mineral composition of the gangue play a decisive role in the precipitation of heavy metal elements. In this study, the microstructure, mineral composition, and precipitation of heavy metal elements of coal gangue with different weathering degrees were analyzed through electron microscopy, X-ray diffraction, and static immersion leaching experiments. The following results were derived. (1) After the weathering of the coal gangue, its compactness and integrity changed significantly. The coal gangue structure transformed from relatively dense to relatively loose, and the development of large pores and fractures changed from basically no development to significant development. (2) After weathering, the contents of kaolinite and illite significantly increased, while that of feldspar significantly decreased. Coal gangue contains a small amount of Mn, Cu, Zn, Ti, Ba, Cl, and other elements. After weathering, the contents of each element were reduced. (3) Under the same conditions, a higher number of heavy metal elements precipitated from the weathered coal gangue than from the fresh coal gangue. The results of this research have significant importance in revealing the precipitation mechanism of heavy metals from coal gangue and in perfecting the theory of underground water environmental protection during solid backfilling mining.

In a word valence judgment task, positive words (e.g., excellence) are judged faster when presented at the top (congruent position) than at the bottom of the screen (incongruent position), whereas the opposite pattern occurs for negative words (e.g., disaster). This spatial-valence metaphoric congruency effect reflects top-positive/bottom-negative metaphoric association and may be attributed to at least three possible mechanisms: spreading activation between spatial and valence concepts (activation account), epistemic function that a conceptual metaphor serves to reduce the uncertainty associated with valence concepts (epistemic account), and/or the extent to which spatial-valence metaphoric association is relevant to task demand (relevance account). In three experiments, we manipulated congruency proportion, target eccentricity, and valence strength in a word valence judgment task to test these three possible accounts. Results showed that the metaphoric congruency effect was larger when a high (vs. equal) proportion of targets appears in congruent, relative to incongruent, position, and for targets with strong (vs. weak) valence. However, the effect in reaction time measure was not modulated by whether the target appeared in the position being near vs. far away from the center of the screen. The overall findings are better accommodated by the relevance account. The implications of the current findings on other theoretical accounts, such as Conceptual Metaphor Theory and polarity correspondence account, are also discussed.

Modality switching cost indicates that people’s performance becomes worse when they judge sequential information that is related to different sensory modalities than judging information that is related to the same modality. In this study, we conducted three experiments on proficient and non-proficient bilingual individuals to investigate the modality switching costs in L1 and L2 processing separately. In Experiment 1, materials were L1 and L2 words that were either conceptually related to a visual modality (e.g., light) or related to an auditory modality (e.g., song). The modality switching costs were investigated in a lexical decision task in both L1 and L2. Experiment 2 further explored the modality switching costs while weakening the activation level of the perceptual modality by adding a set of fillers. Experiment 3 used a word-naming task to explore the modality switching effect in language production in L1 and L2. Results of these experiments showed that the modality switching costs appeared in both language comprehension and production in L1 and L2 conditions. The magnitude of the modality switching costs was conditionally modulated by the L2 proficiency level, such as in the L2 condition in Experiment 1 and in both L1 and L2 conditions in Experiment 3. These results suggest that sensorimotor simulation is involved in not only language comprehension but also language production. The sensorimotor simulation that is acquired in L1 can be transferred to L2.

In this paper, we deal with the robust passivity problem for coupled reaction-diffusion Cohen-Grossberg neural networks (CRDCGNNs) with spatial diffusion coupling and state coupling. First, we present the network model for CRDCGNNs with state coupling and establish some robust passivity conditions for this kind of CRDCGNNs. Then, the investigation on robust passivity for CRDCGNNs with spatial diffusion coupling is carried out similarly. At last, the feasibility of the obtained theoretical results is demonstrated by one example with simulation results.

Temperature-dependent polymorphic phase transition in (K, Na)NbO3 (KNN) inevitably causes the fluctuation of their electrical properties with temperature variation. Here, we investigate the temperature-sensitive electrical properties and their structure/physical origins in a paradigm KNN-based piezoceramic. The orthorhombic–tetragonal (O–T) phase transition exhibits a degenerate dielectric anomaly when it moves to a low temperature, as the consequence of diffused phase transition caused by local chemical heterogeneity after adding additives. In this case, electric field-induced maximum and remnant polarization show different variations. Consequently, the elevation of the piezoelectric coefficient (d33 and ) was obviously observed when the temperature goes through the O–T phase transition. We found that elevated d33 principally comes from the dielectric anomaly, and fluctuation is mainly attributed to the distinct degeneration between the maximum and remnant polarization. The best strategy for optimizing piezoelectric stability is to shift O–T to near room temperature to form rhombohedral (R)–O–T or R–T phase boundaries and make the phase transition a diffused process in a wide temperature range. For example, the high and temperature-insensitive d33 (∼385 pC N−1) and (∼480 pm V−1 at 30 kV cm−1) were achieved in the R–O–T region and changed less than 10% when temperature is elevated from room temperature to 80 °C in this KNN paradigm. Our work affords significant guidance for optimizing temperature stability in KNN-based systems.

Underground coal mining leads to environmental problems such as gangue pollution, surface subsidence and soil erosion, etc. Solid backfilling coal mining (SBCM) can control the strata movement, reducing gangue discharge and environmental pollution in mining areas. Gangue solid wastes (GSW) are backfilled into the goaf space as the supports for the overburden strata in solid backfilling coal mining. In this case, GSW are under triaxial compression. The deformation characteristics of the GSW under this loading condition are the key factors determining the control efficiency of strata movement and surface subsidence. The influence of the particle size grade and the confining pressure condition on the deformation and breakage characteristics of the GSW is studied based on large-scale triaxial compression tests in this paper. Also, the effect of particle breakage on the deformation of the GSW is revealed. The results indicate that in the triaxial compression process, the GSW exhibits strain hardening characteristics and volume decrease under compressive loading. The maximum load-bearing stress is more sensitive to the confining pressure condition but less sensitive to the particle size grade. The maximum load-bearing stress increases linearly with the confining pressure. Particle breakage of the GSW is notably influenced by the particle size grade but almost independent of the confining pressure condition. The S1 specimen with a reasonable proportion has the minimum relative breakage index, while the S3 specimen that mainly contains large particles has the maximum relative breakage index. The research outcomes are significant to the understanding of the mechanical characteristics of GSW, the selection and preparation of the backfilling materials in the field practices and the ensurence of the backfilling efficiency.

This paper deals with the general decay synchronization (GDS) and general decay H

Through the analysis of people's lifestyle and cabinet furniture's function, this paper explores the scenarized design of the intelligent lighting system in cabinet furniture of the residence, expounds the control process of the intelligent lighting system, and presents the installation and wiring ways of lighting. It's supposed to reduce costs, improve the comfort level and convenience of installation.

The preparation of 3 kinds of carbonaceous nanocomposites by hydrothermal treatment and subsequent calcination described. The first comprises a nanomaterial of type CuO/g-C3N4, with g-C3N4 in mass fractions of 2, 5 and 7 wt%, respectively. The second comprises CuO/porous carbon (5 wt%), and the third comprises CuO/carbon spheres (5 wt%). All of them were employed to modify a glassy carbon electrode (GCE) to obtain electrochemical sensors for glucose and dopamine. The GCE modified with CuO/g-C3N4 (5 wt%) displays the highest electrocatalytic activity towards glucose and dopamine. Figures of merit for sensing glucose (in 0.1 M NaOH solution) include a wide linear range (0.5 μM to 8.5 mM), a detection limit of 0.150 μM, and a sensitivity of 0.274 μA·μM−1·cm−2 (at a working potential of 0.60 V vs. Ag/AgCl). The respective data for dopamine (in pH 7.0 solution) are linear ranges from 0.2-16.0 μM and 16.0-78.7 μM, a lower detection limit of 60 nM, and an electrochemical sensitivity of 0.834 and 0.331 μA·μM−1·cm−2 (at a working potential of 0.22 V vs. Ag/AgCl). The good performance of the modified GCE is attributed to the synergetic interactions between CuO and the appropriate fraction of g-C3N4, and the improvement of conductivity.

Electric-field-driven polarization in ferroelectrics delivers extraordinary electro-caloric, electro-optic, and electromechanical properties, etc. However, the controllable multifunctional ferroelectric switching between different electro-related performances still faces great challenges and deserves study. Herein, multifunctional BaTiO3 (BT)-based ferroelectrics are conceived tuning electrocaloric and electrostrictive properties by controlling doping site of dopants, namely site selective doping strategy. The well-concerned Ce is selected for its multivalent trait (Ce3+/Ce4+) and effective adjustment of Curie temperature (TC) in BT. Guided by the distinguished dielectric characteristics via doping Ce3+ in Ba site or Ce4+ in Ti site, BT-based ferroelectrics can direct at different applications. For Ba-site doping, in conjunction with ion-size mismatch effect and defect engineering, manipulating TC to room temperature (RT) and driving second-order-like phase transition are obtained simultaneously. Then, large electrocaloric temperature change (∆Tmax=1.3 K) over a broad temperature span (∆T>1 K, 37~70 ℃) is achieved, which is crucial in developing zero-global-warming-potential refrigeration near RT. For Ti-site doping, unique diffuse phase transition is observed without sacrificing TC, leading to multiphase structures and the formation of nanosize domains, hence facilitating polarization rotation. Therefore, an enhanced electrostrictive strain (S>0.17%) with ultra-low hysteresis (Hhyst

Gangue backfilling mining (GBM) can effectively alleviate the gangue accumulation pollution and the overburden aquifer destruction. To efficiently evaluate the reutilization of gangue wastes by GBM and its advantage in overburden aquifer protection, non-Darcy hydraulic properties and deformation behaviors of granular gangues were studied through laboratorial, theoretical, and in-situ aspects. A series of compression and seepage tests on granular gangues under the variable original grain size grade (GSG) and stress rate were conducted. Laboratorial testing results convince that, hydraulic properties (porosity and permeability) of the granular gangue decline with the increasing original GSG and decreasing stress rate. The crushing ratio of the sample increases with the increase of original GSG and the decrease of stress rate. The fractal dimension reveals more obvious increases in the samples with the higher original GSGs and lower stress rates. The Kruger model (a classical theoretical model) was employed to predict the permeability evolution based on the porosity. However, the invalid pores in rocks would result in the model's underestimation. To this end, an improved model was established to predict the permeability evolution by the fractal dimension, and the improved Kruger model has better accuracy than the original one. Finally, according to the laboratorial testing and theoretical predicted results, friendly-environmental strategies for overburden aquifer protection were proposed. The effectiveness of these strategies was successfully verified by an in-situ application. It is concluded that the high filling stress, low gangue original GSG, and low filling stress rate in GBM can effectively reduce the risk of overburden aquifer destruction.

This paper has retrieved 979 literatures in the field of visualization of cultural heritage information between 2000 and 2020 from Web Of Science core collection. With the keys words as the unit of analysis, cluster analysis and co-word analysis as the research methods and SciMAT as the tool, it has identified research highlights and evolution paths in different periods. The research has found that research topics vary a lot in different periods. Part of the thematic studies are strongly related in sequence, the evolutionary relations between topics gradually become complex in the middle and latter period, and 5 evolution paths are presented in general. System is the main research interests and will continue to be the research highlights. Museum becomes a fundamental topic with great potential in the field after continuous integration and regeneration. 3-D visualization, with the largest time span and various research contents, is the fundamental topic in the field.

IntroductionTo strengthen the care capacity of primary facilities, China has vigorously promoted the construction of a hierarchical medical system and a family doctor care system. In July 2017, a family doctor care plan was launched in an urban district of Chengdu, Sichuan Province, and two family doctor contracting service models were adopted, one provided a basic-service package and the other a paid-service package. In order to evaluate the effect of different models on diabetic patients, this study conducted a real world study based on the district healthcare database.MethodsDiabetic patients who contracted family doctor services January 2018 to January 2019 as reported in the database were enrolled in the paid- or basic-service group. Propensity score matching (PSM) was conducted to balance the distribution of covariances between the groups. The results of the first and last examination of glycosylated hemoglobin, low-density lipoprotein cholesterol (LDL-C), systolic and diastolic blood pressure in the groups were compared by independent sample t-test and chi-square test.ResultsIncluded were 4,871 patients in basic-service and 394 patients in paid-service. In both groups the total control rates of blood pressure, glycosylated hemoglobin and LDL-C at the last physical examination were 43.67, 79.28 and 51.11 percent, respectively, a significant increase from pre-test. The combined control rates of HbAlc, LDL-C and blood pressure in the basic- and paid-service group were 20.76% and 22.37%, respectively. After PSM, there was no significant difference between the groups.ConclusionsUp to now, there is no significant difference between basic-service and paid-service family doctor contracting service models in improving the comprehensive control rate of diabetic patients. The possible reasons may be that the quality and content of paid-service is not as good as expected, the period of implementation is not long enough and the sample size of paid-service patients is limited.