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Objective. This study seeks to explore the efficacy and prognosis of stereotactic aspiration for malignant middle cerebral artery infarction (mMCAI). Methods. A total of 50 mMCAI patients who were diagnosed and treated in our hospital from January 2018 to June 2020 were collected and then randomly divided into control group (decompressive craniectomy, n = 24) and study group (stereotactic aspiration, n = 26). After 1 and 6 months of treatment, the scores of the National Institutes of Health Stroke Scale (NIHSS), Glasgow Coma Scale (GCS), Barthel Index, and modified Rankin Scale (mRS) were used to evaluate the therapeutic effect. Additionally, the mortality and survival rates after treatment were recorded to compare the prognostic effect between the two groups. Results. One month after treatment, the GCS scores and Barthel Index score increased in both the control and study groups and were significantly higher in the study group. The follow-up results at 1 and 6 months after treatment showed that in comparison with the control group, stereotactic aspiration led to a higher survival rate and lower mortality rate; the latter had superior NIHSS score and mRS score and better prognosis. Conclusion. In comparison with decompressive craniectomy, stereotactic aspiration shows outstanding clinical efficacy and more advantages in the treatment of mMCAI. Therefore, stereotactic aspiration is more worthy of clinical application.

In this study, we explored the effects of photobiomodulation (PBM) on the functional damage of human embryonic skin fibroblasts (CCC-ESFs) in a high glucose environment, as well as the effects of PBM on tissue repair, to provide a theoretical basis for application and promotion of dual-wavelength laser therapy in clinical practices. CCC-ESFs were cultured in vitro for 2 d in a high glucose medium, and then irradiated with a 635/808 nm dual-wavelength semiconductor laser at a dose of 20 mW/cm2, 0–24 J/cm2. Cell proliferation, reactive oxygen species (ROS) production, antioxidant enzyme activity (CAT, SOD), lipid oxidization capacity (MDA), cell growth factors, and the expression of matrix metalloproteinases (MMPs) and matrix metalloproteinase inhibitors (TIMPs) were assessed. We found that PBM can enhance the proliferation of fibroblasts, improve the inhibitory effects of the high glucose environment on cell proliferation, increase intracellular ROS production, enhance the activity of antioxidant enzymes, and stimulate cytokine secretion. Furthermore, PBM was found to inhibit the expression of MMPs, increase the expression of TIMPs, reverse the overexpression of MMPs/TIMPs caused by high glucose, and promote wound healing.

Manipulating the structure of Bi-based pyrochlores can produce excellent physicochemical properties and novel phenomena due to lattice disorders and distortions. Herein, bismuth iron niobate pyrochlores via high-level Co-doping were successfully fabricated by a sol-gel auto-combustion method and the doping effects on their structural, magnetic, dielectric and sonocatalytic properties were systematically investigated. Rietveld refinements revealed substituting Fe sites with Co ions (at a ratio of 30%–80%) can maintain the pyrochlore phase and induce larger lattice distortion. New dielectric relaxation and outstanding magneto-dielectric effect with a maximal 4% coefficient were clearly observed in the heavily Co-doped sample at low temperatures, which correlate with structural disorder and magnetic state transitions. New types of dielectric anomalies that gradually change the relative permittivity but maintain the dielectric loss almost constant with increasing temperature or frequency and can be tuneable at different doping levels were first observed above room temperature. The activation of ultrasonic vibration-driven degradation in the specimens was evaluated by the catalytic oxidation of dye, and the Fe/Co-coexisting catalysts exhibited superior sonocatalytic activity with magnetic recyclability, opening up a new pathway of developing feature-rich pyrochlores in the catalytic field.

The chain of short linear tool path segments is the most common form for the five-axis machining by Computer Numerical Control (CNC) machines. The connection points of the linear path segments lead to the discontinuities in position, velocity, acceleration, and jerk, resulting in fluctuation of machine motion which leaves undesired marks on the finished surface. This paper presents a geometric smoothing algorithm by enforcing the continuity of first, second, and third geometric derivatives of the splined path segments at their meeting points for the five-axis machining of curved surfaces. The linear tool path segments are first smoothed by Bezier splines while constraining the path errors within a set tolerance. The tool path segments, that cannot be smoothed within the path error limit, are smoothly connected at the connection points. The tooltip position and tool axis orientation displacements are synchronized to avoid discontinuous displacements along the tool axis. The proposed algorithms are demonstrated with simulations and experiments in following a five-axis, curved tool path on a CNC machine tool. It is shown that the proposed G3 continuous tool path algorithm gives smoother tool-tip and tool axis orientation, reduces the tracking errors, contour errors and amplitudes of jounce at the connections of segments along the tool path, leading to the smoother surface for the precision five-axis machining of sculptured surfaces.

The search for cost-efficient and earth-abundant electrocatalysts for the hydrogen evolution reaction/oxygen evolution reaction has received considerable attention. The in situ growth of vertical two-dimensional (2D) nickel phosphorus trisulfide (NiPS3) nanosheets on nickel foam (NiPS3/Ni) by one-step chemical vapor transport treatment of nickel foam using red phosphorus and sulfur powder is presented. Benefitting from the unique three-dimensional (3D) structure with a large exposed active surface area from vertically aligned nanosheets and facilitated electron transport along 2D nanosheets anchored on conductive nickel foam, the NiPS3/Ni electrode requires low overpotentials of 74 mV at 10 mA cm−2 towards the hydrogen evolution reaction (HER) and 283 mV at 20 mA cm−2 towards the oxygen evolution reaction (OER) in alkaline solution. Remarkably, the constructed two-electrode alkaline water electrolyzer using NiPS3/Ni as both anode and cathode catalysts only requires a voltage of 1.60 V to reach a current density of 10 mA cm−2. The low cost, facile fabrication process, and desirable catalytic performance make the self-supported NiPS3/Ni electrode a promising electrocatalyst for practical water electrolysis.

The manipulation of layer-stacked interfaces inside layered perovskite oxide structures can lead to collective phenomena and extraordinary functionalities, originating from local structural distortions near correlated interfaces and the broken inversion symmetry of periodically repeating layer cells. In this work, the nanoscale control of disorder-to-order layer stacking was achieved in an Aurivillius-type layered oxide, with the structure of a basic perovskite motif sandwiched between Bi–O layers, through simple stoichiometric ratio control or ion substitution at A- and/or B-sites. Tunable layer structure evolution from a disordered mixed-layer structure composed of 4-layer and 5-layer phases to a homogeneous layer structure was clearly observed via utilizing X-ray diffraction and Raman techniques. Such layer structure modulation induces variable mixed-layer interfaces and special OPB defects, which generate perturbations in local order parameters, such as polarization and strain, thus giving rise to enhanced ferroelectric and magnetic properties, anomalous magnetic behavior, and magnetodielectric effects. More importantly, the use of minor La and Co co-doping in phase-modulated materials can generate much larger magnetic coercive fields, reaching ∼20 kOe at 50–100 K, arising from strong interactions between the anti-ferromagnetic matrix and short-range ferromagnetic clusters. Our findings offer a route to the rational fabrication of functional layered perovskites and shed new light on the design of single-phase multiferroics, with the potential for feature-rich applications.

To investigate the role of different pattern of ambient air pollutants exposure during early life on childhood pneumonia, we conducted a retrospective cohort study of 3226 preschool children aged three to six years in Shenzhen, China during 2015 to 2016. Each child's exposure to three main air pollutants (PM10, SO2 and NO2) was calculated by the inverse distance weighted method. Multiple logistic regression analysis was used to investigate the pneumonia risk of early life exposure to air pollution. A relatively high prevalence of pneumonia (24.3%) among preschool children in Shenzhen was significantly associated with exposure to PM10 and SO2 during the first year of life, with adjusted odds ratios = 1.24 (1.05, 1.46) and 1.20 (1.05, 1.38) respectively. However, we observed no relationship between NO2 exposure and childhood pneumonia in pregnancy and first year of life. Sensitivity analysis suggested that boys, younger children (three to four years), non-preterm children, children without parental atopy and with exposure to environmental tobacco smoke were more susceptible to the impact of exposure to PM10 and SO2 on their suffering of pneumonia during their first year of life. Early-postnatal exposure to classical air pollution at low concentration during the first year of life can have an important role in enhancing the risk of childhood pneumonia, especially with the sensitive population.

Under the background of the high youth unemployment rate in the world, how to encourage college students to carry out entrepreneurial activities is the focus of the whole society. But even if government and college provide such a high-quality entrepreneurial platform for college students, the rate of youth entrepreneurship in the world is still relatively low. On the basis of the questionnaire of 385 college students concentrated in several colleges in Hubei Province of China, this paper used independent sample T test, single factor analysis method, multiple comparison test (LSD), correlation analysis, regression analysis and other empirical analysis methods to analyze the impact of entrepreneurial education as well as entrepreneurial policy on college students' entrepreneurial intention, and verified the intermediary role of entrepreneurial self-efficacy. The research conclusions mainly included: (1) Part of the control variables will affect entrepreneurial intention; (2) Entrepreneurial education, entrepreneurial policy positively and significantly affect the entrepreneurial intention of college students; (3) Entrepreneurship self-efficacy plays an intermediary role in the influence of entrepreneurship education and entrepreneurial policy on entrepreneurial intention. According to the conclusion of the research, this paper put forward some suggestions for government, university as well as students, and tried to provide the gamut of support system of entrepreneurship, so as to stimulate the entrepreneurial intention of college graduates and improve the entrepreneurial rate.

Among the factors that lead to the reduction of the efficiency and stability of perovskite solar cells (PSCs) using [6,6]-phenyl C61 butyric acid methyl ester (PCBM) versus those of conventional structure, is the difficulty involved in realizing a high-quality film, and the non-radiative recombination that takes place at the interface between PCBM and perovskite. Our present work proposes a fabrication technique capable of overcoming these issues. Organic small molecule material was introduced along with PCBM, to obtain a homogeneously seamless film that plays the role of a dipole layer. The incorporated triethyl citrate (TEC) boosts the power conversion efficiency (PCE) from 14.56% to 17.86% with suppressed hysteresis, which originates primarily from the efficient electron transfer between the perovskite/PCBM and the Ag cathode interface. The results of electrochemical impedance spectroscopy measurements imply efficient electron transfer, low series resistance, and large recombination resistance in the photovoltaic device employing PCBM@TEC as the cathode interfacial layer. Specifically, the highly hydrophobic PCBM@TEC cathode interfacial layer (CIL) showed higher resistance to moisture, leading to a more environmentally-stable device. The results also showed the efficiency of the device retained 84% of its initial value after 30 days of operation under ambient conditions, which shows a visibly superior stability compared to a reference device that, under the same environment, retained only 37% its initial efficiency. Such advancement in the operational efficiency and stability of the device, will contribute to the longevity and cost-effectiveness of inverted PSC devices.

This study proposed a novel fluidized bed (NRFB) to realize gas-solid non-catalytic continuous reaction. Gas and solid flowed in reverse direction in NRFB, achieving high-efficiency contact between particles and gas to form particles. The discrete phase model was used to simulate the gas-solid two-phase flow in NRFB. Basis on an optimum operating gas velocity, the characteristics of the gas-solid two-phase flow field and sodium phenolate carboxylation in NRFB were analyzed. The equal-area torus method was proposed to explore the radial particle distribution. The results showed that the gas in NRFB could be in full contact with solid particles. The introduction of the grid trays could significantly improve radial distribution and increase the residence time of sodium phenolate particles in the dense phase section, thereby improving the reaction efficiency. The simulation results can provide guidance for the determination of the operation parameters in pilot and industrial production of gas-solid non-catalytic reactions.

FoxA2 is an essential transcription factor for liver organogenesis and homeostasis. Although reduced expression of FoxA2 has been associated with chronic liver diseases, hepatic progenitor cells (HPCs) that are activated in these circumstances express FoxA2. However, the functional effects and underlying mechanism of FoxA2 in HPCs are still unknown. As revealed by immunostaining, HPCs expressed FoxA2 in human cirrhotic livers and in the livers of choline-deficient diet supplemented with ethionine (CDE) rats. Knocking down FoxA2 in HPCs isolated from CDE rats significantly increased cell proliferation and aerobic glycolysis. Moreover, gene transcription, protein expression, and the enzyme activities of hexokinase 2 (HK2) were upregulated, and blocking HK2 activities via 2-deoxyglucose markedly reduced cell proliferation and aerobic glycolysis. Kyoto Encyclopedia of Genes and Genomes analysis revealed that FoxA2 knockdown enhanced the transcription of genes involved in the phosphatidylinositol 3-kinase (PI3K)/protein kinase B (Akt) pathway and triggered downstream Akt phosphorylation. Blocking the PI3K/Akt pathway by Ly294002 inhibited HK2 activities, aerobic glycolysis, and cell proliferation in FoxA2-knockdown cells. Therefore, FoxA2 plays an important role in the proliferation and inhibition of HPCs by suppressing PI3K/Akt/HK2-regulated aerobic glycolysis.

Co-doping of piezoelectric ceramics by amphoteric rare earth ions has resulted in synergistic improvement of their electrical properties. In this study, Yb3+ and Dy3+ co-doped lead-free 0.5BaTi0.8Zr0.2O3-0.5Ba0.7Ca0.3TiO3 nanoparticles and ceramics were prepared. The synthetic process of the nanoparticles by a modified Pechini polymeric precursor method was studied by FT-IR, TG-DSC, HRTEM, XRD, and Raman spectroscopy. The densified (>96%) ceramics were obtained by sintering the as-synthesised nanoparticles at 1220 °C, and the influence of Yb content (x) on the phase structure, permittivity, ferroelectricity, piezoelectricity, and thermophysical performances was studied. Initially, for low x, Yb3+ occupied A sites in the perovskite structure as donor dopants, resulting in improved ferroelectric and piezoelectric properties and decreased domain switching activation energy with few oxygen vacancies; while the electrical properties deteriorated as x increased further. The relationships of the defect dipole-induced electrical properties or/and activation energy with internal stress, structure distortions, and impurity phase were deduced. The optimum piezoelectric coefficient (d33* = 683 p.m./V) with the lowest domain switching activation energy (Ea = 0.233 eV) was determined at x = 0.60 mol%, indicating that the ceramics were suitable for practical applications.

The expression of epidermal growth factor (EGF) is increased during liver fibrogenesis, and EGF receptor (EGFR) antagonist could attenuate liver fibrosis. Since EGFR is highly expressed by hepatocytes and cholangiocytes in cirrhotic liver, whether hepatic stellate cells express EGFR in response to EGF still needs exploration. Although EGFR antagonist could attenuate liver fibrosis, many ligands with EGF-like domains, besides EGF, can function through EGFR. Whether specifically blocking EGF could attenuate bile duct ligation (BDL)-induced liver fibrosis has not been revealed. BDL induced biliary infarcts and matrix deposition in mouse liver, and EGFR was expressed and phosphorylated by α-smooth muscle actin (αSMA)-positive myofibroblasts. LX-2 cells expressed EGFR, and these receptors were phosphorylated in the in vitro culture system. Growth curve and cell cycle analysis revealed that EGF could enhance cell proliferation of LX-2 cells. In addition, administration of EGF antibodies markedly reduced the EGF level in serum and the deposition of extracellular matrix in the liver of BDL mice when compared to IgG administration. Administration of EGF antibodies also reduced the phosphorylation of EGFR and the percentage of Ki-67-positive or PCNA-positive liver myofibroblasts of BDL mice when compared to IgG administration. Therefore, activated hepatic stellate cells express EGFR, thus being responsive to EGF signal, and administration of EGF antibodies could attenuate liver fibrosis by restricting the proliferation of myofibroblasts.

The space-confined synthesis method has been an efficient way for the preparation of linear carbon chains. However, the large-scale preparation of linear carbon chains still faces many challenges due to the lack of methods for the large-scale synthesis of precursors, such as short carbon chains (polyynes), and regulation technology for the transport of reactants in one-dimensional space. Here, we report a facile method for the rapid preparation of polyynes in large quantities using a commercial laser marking machine. Spectroscopic characterizations show that a large number of polyynes, such as C8H2, C10H2, C12H2, and C14H2, can be produced by ablating the graphite plate immersed in the organic liquid using a laser marking machine. The results of in situ Raman spectroscopy investigation of C2n H2-filled single-walled carbon nanotubes further confirm that a variety of polyyne molecules are synthesized. Meanwhile, in situ Raman spectroscopy also shows that the local heating treatment can accelerate the filling process of C2n H2 into one-dimensional channels. This work provides new insights into the study of linear carbon chains and space-confined synthesis methods.

Acute lung injury (ALI) impaired the function of blood oxygen exchange function, resulting in tissue hypoxia and patient death. Recently, human umbilical cord mesenchymal stem cells (hUCMSCs) are thought to mitigate the effects of ALI, which boosts researchers' interest in employing stem cell-based therapies to manage ALI. However, as a novel therapy, hUCMSCs still face various limitations such as migrating weakly and insufficient proliferation in vivo. Photobiomodulation (PBM) effciently promotes cell proliferation, migration and homing, which presents a promising strategy for overcoming above limitations. In this study, PBM was emerged to intervene hUCMSCs through detecting cell proliferation, oxidative stress-related factors and inflammatory factors. These results assuredly confirmed that PBM enhanced the antioxidant capacity of cells and improved cell survival in vitro experiments. In vivo, PBM-intervened hUCMSCs intuitively reduce thickness of alveolar septum, excessive secretion of inflammatory factors, relieves bleeding, edema and fibrosis. As a physical intervention, PBM further strengthens the therapeutic effect of hUCMSCs and depicted a hopeful therapy in ALI treatment.

Rare earth element-doped piezoelectric ceramics exhibit excellent electrical properties. Platinum group elements can render them catalytically active and conductive. In this study, lead-free Ba0.95Ca0.05Ti0.94Zr0.06O3 piezoelectric ceramics doped with 0.12% lanthanum and iridium (varying contents, x) were sintered at 1260 °C. The thermal expansion coefficients and fracture strengths of these ceramics were affected by their strains and structural defects. With an increase in x, the diffuse phase transition weakened first and then accelerated (with further increase in x (> 0.75%)). The best ferroelectric properties were obtained at 400 ms and 25 kV/cm. The effects of the phase, structural defects, and internal stress on the electrical properties of the ceramics were systematically investigated. Relations of electrical properties, mechanical strength, and thermophysical performances were originally researched. In addition, the electrical properties (piezoelectric constants, ∼270 pC/N; mechanical quality factors, ∼70) and thermophysical performances (thermal expansion coefficient, ∼1.2 × 10−5 K−1) of the ceramics were found to be suitable for practical applications.

Proper valence band offset at the perovskite/hole transport material interface is critical to obtain high performance perovskite solar cells. The Cu2ZnSn(Se1-xSx)4 compound is a potential candidate of hole transport material for perovskite solar cells and exhibits tunable band gap from 0.95 eV for Cu2ZnSnSe4 to 1.5 eV for Cu2ZnSnS4 with different S/(S+Se) ratio, which offers a feasible approach to engineering the valence band offset at the perovskite/Cu2ZnSn(Se1-xSx)4 interface. Here, the valence band offset engineering at the perovskite/Cu2ZnSn(Se1-xSx)4 interface is studied through numerical simulation with SCAPS package. The valence band offset can be tuned from negative value to positive value with different Cu2ZnSn(Se1-xSx)4 composition. With optimized S concentration, a suitable valence band offset (0.27 eV) is obtained, leading to a power conversion efficiency of 20.25%. Further optimization of thickness, defect density, and acceptor density of the Cu2ZnSn(Se1-xSx)4 transport layer is conducted, and power conversion efficiency of 20.77% is obtained. This study here provides a guidance to further optimize the performance of perovskite solar cells with Cu2ZnSn(Se1-xSx)4 hole transport material.

Employing additive to regulate the morphology of perovskite film is an effective method to enhance both the power conversion efficiency and long term stability of organic-inorganic hybrid perovskite solar cells. Here, we demonstrate that guanidinium thiocyanate (GuSCN) is a suitable additive for methylammonium lead iodide (MAPbI3) perovskite materials. Addition of GuSCN into MAPbI3 can simultaneously enhance the crystallinity, enlarge the crystal size, and reduce the trap density of the perovskite films. As a result, the MAPbI3 perovskite with 10% GuSCN exhibits superior power conversion efficiency of 16.70% compared to the pristine MAPbI3 perovskite solar cell (15.57%). At the same time, the MAPbI3 perovskite solar cell with GuSCN additive shows better stability, power conversion efficiency retains ∼90% of its initial value compared to only ∼60% for pristine MAPbI3 perovskite solar cells after being stored for 15 days without encapsulation.

Bismuth-based pyrochlore oxides in which the structure tolerates significantly lower site misplacement and markedly higher vacancy concentrations exhibit unique physicochemical properties; therefore, manipulation of such a crystal structure by chemical substitution may give rise to intriguing phenomena and extraordinary properties. Herein, we have systematically investigated the effects of the Co substitution on the structural, magnetic, magneto-dielectric and optoelectronic characteristics of ternary bismuth iron niobate pyrochlore oxide with the highest recorded Fe content. Structural modulation induced by the Co dopant was clearly observed by Rietveld refinements and Raman spectra, which are attributed to the displacive disorder nature of the pyrochlore structure and lattice distortions induced by the substitution of Fe sites with Co ions. A dielectric anomaly exhibits a distinct peak temperature shift and intensity increasing under a magnetic field of 1 T, which may be explained in terms of the magnetic state transition and magnetic interactions or fluctuations, and the obvious magneto-dielectric (MD) effect with a maximal MD coefficient of ∼4% at ∼1 MHz was firstly found in ferroelectric Bi pyrochlores. Remarkably, the Fe/Co-coexisted nanoparticles showed an anomalous light absorption and exhibited an enhanced visible-light-responsive photocatalytic performance by means of the dye decomposition and the photoelectrochemical technique. The findings indicated structural modulation using element substitution can realize excellent physicochemical behaviours and novel phenomena and shed new light on controlling the atomic structure and functional properties in isostructural pyrochlore oxides.

In this paper, a real-time feedrate dynamic planning method in CNC system is studied. Machine feedrate is affected by interference conditions from external environment. Commonly used machining modes such as Exact Stop Mode and Continuous Mode are both influenced by emergency stop, feedrate reset and feedrate override signals. The corresponding dynamic planning method is studied in this paper. Segment linking method is applied in Continuous Mode, guarantees constant velocity while traversing multi-blocks, and ensure acceleration within limits. In Exact Stop Mode, inference signals only affect the current segment. In Continuous Mode, always not only the current velocity profile is alternated, but also the successor blocks are affected. The proposed method response in time, the current interpolation period recalculates time parameter when influence signal comes and starts to response in action. The controller changes its logic as soon as interference signal comes and adjusts trajectory planning profile in real-time. The proposed method acts before interpolation, in Cartesian space. Experimental results show the effectiveness of the proposed dynamic planning method.

Lines and circular arcs are commonly used in CNC systems, the numerical controller always treats them separately, in two different routines. In this paper, a circle discrete method is proposed, both linear segments and circular arcs are treated as straight lines in motion layer under permitted tolerance. One major barrier of trajectory planning on G01 segments is the transition velocity at corner. In the requirement of high speed and high accuracy, a symmetrical corner transition method is studied, with the characteristics of simplicity and computing efficiency, promotes velocity at corner. Furthermore, a look-ahead method is applied to foresee the following path and readjust corner velocity. Based on real-time period routine, trapezoidal velocity profile is used for trajectory generation. The circle discrete method is integrated in interpreter software, the symmetrical corner transition method and intelligent look-ahead algorithm are integrated in motion control module. These software modules are separately tested and integrated together. Simulation results and practical experiments verified the effectiveness of the proposed method.

Relaxer ferroelectrics are highly attractive in electrocaloric due to large breakdown electric field and wide phase transition temperatures, which has great potential applications in solid-state cooling. In this work, relaxer ferroelectrics are synthesized by a traditional solid state reaction method. Phase transition and relaxer characteristics are studied by temperature dependent dielectric spectrums. Temperature dependent ferroelectric properties are also studied to calculate electrocaloric effect. Maximum value of refrigeration efficiency η ( ΔT/ΔE ) is about 0.079 K·cm/kV, our result lays a foundation and provides a reference for studying high efficiency solid-state electrocaloric refrigeration. Pyroelectric energy harvesting are studied, maximum pyroelectric energy harvesting is 279 kJ/cm 3 .

Ba(1−x)CaxTi0.92Zr0.08O3 (BTZ-xCa; x = 0–0.20) lead-free ceramics were prepared at a low temperature of 1210°C using as-synthesized nanoparticles through a modified Pechini method. The structure, permittivity, ferroelectricity, piezoelectricity, and thermal expansion characteristics of the ceramics that were influenced by varying calcium contents were studied in detail. X-ray powder diffraction and Raman results suggested that calcium could not induce the rhombohedral phase transition, and impurity phases were detected with excessive x. The electrical properties were basically elevated firstly in the room temperature direction of the temperature of phase transitions for orthorhombic-to-tetragonal with weaker internal stress, and then they apparently deteriorated with the shrunk octahedron size and strongly distorted structure with an increase of calcium content. The optimum electrical properties, i.e., d33, kp, and Qm of the BTZ-xCa ceramics were 261 pC/N, 24.9%, and 98 were obtained when the calcium content was 0.05, respectively. Additionally, the thermal expansion coefficient was studied for providing guidance on the ceramic materials production and usage.

Aurivillius-type multiferroic oxides are increasingly being studied for potential application in multifunctional areas because of their feasible platforms incubating photonic, electric, magnetic, etc. properties. Here, we report the original observations of the dielectric relaxation, electromagnetic properties and high-performance microwave absorption of the single-phase Aurivillius-type ceramics. Two thermally activated relaxation processes were determined by the frequency-dependent behaviour of the dielectric loss peak at low and high temperatures. The complex permittivity and permeability were measured at frequencies 2–18 GHz and the microwave attenuation performances were calculated from the experimentally determined electromagnetic parameters. Significantly, the damped dielectric and magnetic resonances were clearly observed at 12–14 GHz and the excellent microwave absorption properties were presented for the first time and are sensitive to the sample thickness. The minimum reflection loss (RL) surpasses − 30 dB at different thicknesses. Especially, the minimum RL reaches − 70.1 dB at 13.2 GHz and the absorption bandwidth (RL≤ −20 dB) is close to 12 GHz (5.7–17.7 GHz). This work opens up a new pathway to develop Aurivillius-type multiferroic oxides in electromagnetic wave attenuation materials.

(1 − x)Ba0.95Ca0.05Ti0.94Zr0.06O3–(x)Dy (x = 0–0.90 mol%) lead-free ceramics were prepared at 1190 °C with as-synthesized nanoparticles via a modified Pechini polymeric precursor method. X-ray powder diffraction, Raman spectrometer, and X-ray photoelectron spectroscopy were used to investigate the phase, symmetry, and valence state, respectively. The results indicated dysprosium could induce the phase transformation from O to R. The mechanism of defect complexes and oxygen vacancies that influenced by various dysprosium contents were discussed in detail. The results of dielectric, ferroelectric, and piezoelectric characteristics suggested the electrical properties were initially elevated with a trifling addition of dysprosium contents, and then decreased with further increased x. Moreover, reasons for diversified electrical properties, i.e., imbalanced long-range and short-range forces, changed octahedron structure, defect dipole, pinching effects of domain wall and element electronegative, were all stated in detail. The optimal physical properties, d33 = 371 pC/N, Qm = 87, and CTE2 = 1.23 × 10−5 K−1, were detected at x = 0.60 mol%, and those findings were regarded as prospect in the development of lead-free ferroelectric ceramic materials.

Designed with electron-donating and electron-withdrawing moieties as donors and acceptors, respectively, a series of novel organic dyes for dye-sensitized solar cells (DSCs) are simulated using density functional theory (DFT) and time-dependent DFT (TD-DFT) methods The interacting dye/TiO 2 systems are also studied to further explore the interfacial injection process of photo-excited electron. The model dye C275 is featured with donor/acceptor (D/A) molecular architecture, which is primary to achieve the easy charge-transfer excitation and suitable energy levels alignment. To date, considerable efforts are devoted to the design and synthesis of D/A type organic dyes, and the initial configurations are typically comprised of N-annulated perylene donor, porphyrin linker, and carboxylic acid acceptor. Our results show that, the electronic levels and optical absorption properties can be tuned gradually by introducing auxiliary donor units or electron-deficient spacer in acceptor groups. Moreover, the designed dyes also exhibit good performance in terms of photoinduced charge transfer, electron injection, and dye regeneration, etc . Through structural modification of donor moieties, the new tailored dyes provide appropriate energy levels, strong light-harvesting and easy charge separation. Meanwhile, the distinct red-shift of optical absorption and large amount of transferred charges are also obtained by structural tailoring of acceptor groups, whereas the large values of injection time may be harmful for the interfacial photoelectron injection. Therefore, comparing with donor modification, it should be more carefully to choose appropriate acceptor group with the balance of various energetic and kinetic factors for the rational design of high-efficient organic dyes.

PEDOT:PSS is one of the most widely used hole transporting layer for inverted perovskite solar cells. Yet the performances of the corresponding perovskite solar cells are not satisfactory. Here, we demonstrate that KCl modified PEDOT:PSS film can promote the crystallization of perovskite film and enlarge the perovskite crystals. At the same time, KCl can diffuse into the perovskite film and effectively passivate the defects. As a result, inverted perovskite solar cells fabricated on 10 mg mL−1 PEDOT:PSS/KCl films exhibit an average power conversion efficiency of 16.24 %, which is enhanced by 17.77 % compared with the reference perovskite solar cells. Open circuit voltage of 1.009 V and power conversion efficiency of 17.09 % have also been demonstrated using the optimized 10 mg mL−1 PEDOT:PSS/KCl films.

Co-doped La3Ni2O7 single phase mix-conductors are successfully fabricated and investigated as cathodes for solid oxide fuel cells. Electrochemical measurement suggests that the polarization resistance of the cell using such cathodes reduce largely when increasing the Co content in La3Ni2O7 cathodes, which is about 1.12 Ω cm2 for La3Ni1.9Co0.1O7 and 0.35 Ω cm2 for La3Ni1.6Co0.4O7 both measured at 650 °C. X-ray photoelectron spectroscopy analysis suggests that the Co-doped La3Ni2O7 samples keep much more oxygen vacancies at high temperatures when compared with those undoped samples, which can benefit both oxygen adsorption and oxygen ion diffusion process in the oxygen reduction reaction. Moreover, both conductivity and magnetic measurements indicate that the covalence of B-O bonds in Co-doped samples can be largely improved because of the more localized 3d electrons in the Co substituted samples, which can further help to accelerate the proton diffusion process. The findings in this research demonstrate that the Co-doped La3Ni2O7 with the two-layer structure can be a promising cathode for proton conducting SOFCs, due to its high activity toward the oxygen reduction reaction.