Introduction Pregnant women with pre-excitation syndrome are more likely to develop supraventricular tachycardia (SVT) during pregnancy and delivery, leading to an increased risk of adverse events. Method This was a retrospective study of 309 pregnancies in 280 women (29 women had two pregnancies in this series) with pre-excitation syndrome who delivered at West China Second University Hospital from June 2011 to October 2021. All the 309 pregnant women with pre-excitation syndrome were divided into SVT and non-SVT groups to analyze the cardiac and obstetric complications. Results Among the included pregnant women in the past 10 years, the prevalence of pre-excitation syndrome was 0.24% (309/127725). There were 309 cases with pre-excitation syndrome in all hospitalized pregnant women. Among them, 62 (20.1%, 62/309) had a history of SVT. In the 62 cases with SVT during pregnancy, 22 (35.5%) cases had a history of SVT. Gestational diabetes mellitus was associated with SVT during pregnancy. The cesarean section rate was 88.7% in the SVT group, which was significantly higher than that in the non-SVT group (64.8%) ( P < 0.001). Cases with SVT during pregnancy had more cardiac and obstetric complications. Four fetal deaths were recorded in the SVT group. Additionally, 29 women experienced two pregnancies during the study period, among whom, five received radiofrequency ablation after the first delivery and obtained better outcomes in the second pregnancy. Conclusion The adverse outcomes such as cardiac complications, maternal and fetal complications (PROM, prematurity, SGA, fetal distress, etc.) in pregnant women with pre-excitation syndrome were closely related to SVT, with possible risk factors including history of SVT before pregnancy, cardiac function, heart organic abnormalities, and gestational diabetes mellitus.

The study aims to investigate the influence of infrared emissivity on thermal barrier coating (TBCs) for service applications. Two double-layer TBCs, namely RMgAl11O19/YSZ (marked as RMA/YSZ, R=La, Pr) and conventional single-layer YSZ TBCs, were comparatively tested using a burner rig facility. The microstructure, infrared emissivity, and thermal cycling performance of the three TBCs were investigated. The results demonstrate that the emissivity of PrMA/YSZ has been improved by approximately 20% compared to LaMA/YSZ in the wavelength range of 2-6 mu m, owing to an improvement in electronic transition. Due to higher emissivity, the surface temperature of PrMA/YSZ decreased by 70 degrees C under the same heat flux, leading to a reduction in coating aging and substrate temperature. Accordingly, PrMA/YSZ exhibited the highest thermal cycling lifetime among the three coatings.

The surface of the switchgear is prone to condensation in the high humidity environment, which seriously endangers the operation of the electrical equipment in the cabinet. In order to prevent condensation, fluoro-silicone composite coating with a low surface energy was prepared and studied. The surface morphology of the coating was characterized using SEM. The obtained fluoro-silicone composite coating achieved a contact angle of 143 degrees and surface energy of 10.3 mJ/m(2). Compared with bare tinplate sheets, condensation time of the coating is delayed by 46 min. Compared with the five common protective coatings, there are no obvious droplets on the surface of fluoro-silicone composite coating at the same condensation time, which proves that it has excellent anticoagulant properties. Our study provides significant research and market opportunities for the anticondensation application of the widely used fluoro-silicone coating.

In this work, Yb3Al5O12 (YbAG) garnet, as a new material for environment barrier coating (EBC) application, was synthesized and prepared by atmospheric plasma spraying (APS). The phases and microstructures of the coatings were characterized by XRD, EDS and SEM, respectively. The thermal stability was measured by TG-DSC. The mechanical and thermal-physical properties, including Vickers hardness (H-v), fracture toughness (K-IC), Young's modulus (E), thermal conductivity (kappa) and coefficient of thermal expansion (CTE) were also measured. The results showed that the as-sprayed coating was mainly composed of crystalline Yb3Al5O12 and amorphous phase which crystallized at around 917 degrees C. Moreover, it has a hardness of 6.81 +/- 0.23 GPa, fracture toughness of 1.61 +/- 0.18 MPa m(1/2), as well as low thermal conductivity (0.82-1.37 W/m.K from RT-1000 degrees C) and an average coefficient of thermal expansion (CTE) (similar to 6.3 x 10(-6) K-1 from RT to 660. C). In addition, the thermal shock and water-vapor corrosion behaviors of the Yb3Al5O12-EBC systems on the SiCf/SiC substrates were investigated and their failure mechanisms were analyzed in details. The Yb3Al5O12 coating has an average thermal shock lifetime of 72 +/- 10 cycles as well as an excellent resistance to steam. These combined properties indicated that the Yb3Al5O12 coating might be a potential EBC material. Both the thermal shock failure and the steam recession of the Yb3Al5O12-EBC systems are primarily associated with the CTE mismatch stress.

In recent years, the degradation of zirconia in a humid environment has attracted the attention of researching. In this work, Mg0.09Zr0.91O1.91 (MSZ), Y0.09Zr0.91O1.955 (YSZ) and Ce0.09Zr0.91O2 (CSZ) powders were prepared by co-precipitation method, the corresponding zirconia coatings were fabricated by atmospheric plasma spraying (APS). All coating samples were subjected to hydrothermal treatment to investigate their degradation process in moisture. The evolution of phase composition and microstructure were characterized. Results show that the content of monoclinic phase (m) in MSZ, YSZ and CSZ coating samples increased after hydrothermal treatment, rising by 47 % in MSZ coating, by 31 % in YSZ coating and by 8 % in CSZ coating. The degradation of internal structure of coatings was more serious with the prolongation of hydrothermal treatment time. This is because different stabilizers will cause different oxygen vacancy concentration in the zirconia unit cell, which determines the hydrothermal stability of zirconia. Under the tested condition, CSZ has the lower oxygen vacancy concen-tration (4 %) than MSZ (11 %) and YSZ (7 %), exhibiting better hydrothermal stability.

In a high-moisture environment where dust and coastal saltwater are prevalent, the stability of power equipment can be adversely affected. This issue can result in equipment downtime, particularly for transformers, severely disrupting the continuous operation of DC transmission systems. To address this challenge, a superhydrophobic modified fluorosilicone coating was developed, incorporating anti-stain properties. To tackle this issue comprehensively, an orthogonal experiment was conducted, involving six factors and three levels. The study focused particularly on assessing the impact of water-repellent recovery agents, nanofillers, antistatic agents, anti-mold agents, leveling agents, as well as wetting and dispersing agents on the coating’s surface tension. The results demonstrate that selecting an appropriate base resin and incorporating well-matched functional additives played a central role in effectively reducing the surface tension of the coating. Consequently, optimized coatings exhibited exceptional resistance to stains and displayed strong corrosion resistance.

LaMgAl11O19/Yb2Si2O7 (LMA/YbDS) thermal/environmental barrier coatings (T/EBCs) on SiCf/SiC composites were annealed at 1200 degrees C for 5 h in air or Ar atmosphere. The effect of post-annealing in different atmospheres on the microstructure, thermal shock and steam corrosion of the LMA/YbDS T/EBCs was investigated. Results indicated heat treatment in air and argon eliminated the amorphous in the coatings, avoiding the aging stress associated with the crystallization. And the argon-annealed layers (LMA and YbDS) exhibited the less elastic moduli than the air-annealed ones, resulting in the lower thermal mismatch stress in the argon-annealed T/EBCs upon subsequent thermal cycling. Thus, the argon-annealed T/EBCs exhibited an improved thermal cycling lifetime than the as-sprayed and the air-annealed ones. In addition, the unbroadened vertical cracks in the argon-annealed LMA-TBC layer limited the reactant (water-vapor) access to the silica-TGO, leading to the greater resistance of the argon-annealed T/EBCs against steam corrosion than the other two systems.

Yolk-shelled CoS2 nanospheres are designed through Kirkendall Effect and subsequently converted into defect -rich CdS/CdCO3-CoS2 photocatalysts via in-situ growth method. The optimal CdS/CdCO3-CoS2 exhibits a sig-nificant hydrogen evolution rate of 64867.88 limol h-1 gcat-1 that is 3.23 and 49.45 folds higher than CoS2-CdS and pure CdS. CO2 reduction rate of CdS/CdCO3-CoS2 is detected additionally (654.7 limol h-1 gcat-1). Yolk-shelled CdS/CdCO3-CoS2 induces the multi-scattering of incident light, possessing 1.52-fold H2 production rate than that of full hollow ones. Enhanced photoexcited-carriers migration efficiency is attributed to the synergistic effect between possible Mie resonance at about lambda = 450 nm in yolk-shelled architecture based on Mie's theory and monochromatic light HER test, and the formation of defect energy level within the wide-band gap of CdCO3 in Schottky-type/type II heterojunction. Electron paramagnetic resonance, positron annihilation spectroscopy and density functional theory calculation etc. are employed to validate the presence of oxygen vacancies and the photocatalytic mechanism.

In the long-term working state, stains such as dust, oil, and charged particles in the environment are prone to deposit on the surface of the power equipment, which has great security risks. To achieve anti-stain performance, fluorocarbon composite coating with a low surface energy was prepared and studied. In this paper, SiO2 nanoparticles were used as inorganic fillers and fluorocarbon resin was used as the substrate to form anti-stain coatings. By adjusting and optimizing the ratio of fillers and organic resins, coatings with different static contact angles were constructed. The optimum composite coating has a contact angle of 151 ± 2° and a surface energy of 9.6 mJ/m2. After high-temperature treatment (up to 200 °C), immersion in corrosive solutions (pH 3–11), and sandpaper abrasion (after 5 abrasion cycles), the coating has been proven to show good thermal, chemical and mechanical stability. Our study provides significant research and market opportunities for the anti-stain application of the fluorocarbon composite coating on power equipment.

In the present work, the microstructure deformation and synergetic damage evolution of a three-dimensional textile SiC/SiC ceramic-matrix composite under flexural loading are investigated by in situ digital image correlation at ambient temperatures. The correlations between microstructure evolution and macro-mechanical degradation of 3D textile composites under flexural loading are established based on the experimental results. In addition, by establishing continuum damage mechanics and a thermodynamic framework with synergetic effects of microstructures, a flexural loading-induced damage evolution model is developed to reveal the relationship between the energy release rate and elastic modulus degradation. The proposed model can be used to predict the flexural stress-strain curves of 3D textile SiC/SiC composites to further improve the design and assessment of new textile architectures with specific mechanical properties.

A study of porous YSZ abradable sealing coating (ASC) plasma-sprayed onto SiCf/SiC ceramic matrix composites (CMC) through the compatibility of intermediate layers is reported. The multilayer Si/Yb2Si2O7/LaMgAl11O19 thermal-environmental barrier coating (T-EBC) is served as intermediate layers in consideration of its ability to protect the CMC from recession and ease the misfit of the thermal expansivity. Isothermal exposure and thermal shock tests were conducted at 1200 degrees C and led to the decomposition of t'-ZrO2 phase to t-ZrO2 and c-ZrO2 phases in YSZ topcoat, the formation of mud-cracks throughout the entire coating structure and thermally grown oxide (SiO2), with following an Yb2Si2O7 reaction layer. The measured bond strength of the coated samples was 5.47 +/- 0.85 MPa, and the fracture position mainly happened inside the CMC substrate. The Superficial Rockwell Hardness (HR15Y) considered to be an important factor in abradability increased by only 1.34% after 1200 degrees C isothermal exposure for 100 h, showing excellent high temperature hardness stability. The abradability of the ASC was investigated by a sliding wear test, the fatigue wear mainly occurred in worn scar when encountering Si3N4 ceramic ball with high hardness and low thermal conductivity, while adhesive wear occurred when GCr15 steel ball with low hardness and high thermal conductivity are encountered.

In order to promote the thermal cycling behavior of SiCf/SiC composites at high-speed gas scour and high-temperature environment, we have prepared three-layer Si/Yb2SiO5/LaMgAl11O19 TEBCs onto the surface of SiCf/SiC composites using atmospheric plasma spraying (APS) method. Burner rig tests were performed to evaluate the thermal cycling behavior of TEBCs. Results show that after being tested in high-temperature and high-speed burner flame, only a small number of TEBCs cracked and peeled in the external area of TEBCs caused by the thermal stress and the corrosion of water vapor, but TEBCs did not crack and spall in the center area. The failure mechanism of TEBCs was investigated. Microstructure characterization indicated that the penetrating cracks in TEBCs provided the channel for oxygen and water vapor diffusion to SiCf/SiC composites leading to the severe corrosion of substrate.

MoSi2 doped Yb2Si2O7 composites were designed to extend the lifetime of Yb2Si2O7 environmental barrier coatings (EBCs) via self-healing cracks during high-temperature applications. Yb2Si2O7 -Yb2SiO5-MoSi2 composites with different mass fractions were prepared by applying spark plasma sintering. X-ray diffraction results confirmed that the composites consisted of Yb2Si2O7 , Yb2SiO5, and MoSi2 . The thermal expansion coefficients (CTEs) of the composites increased with an increase in the MoSi2 content. The average CTE of the 15 wt% MoSi2 doped Yb2Si2O7 composite was 5.24 x 10(-6) K-1, indicating that it still meets the CTE requirement of EBC materials. After being pre-cracked by using the Vickers indentation technique, the samples were annealed for 0.5 h at 1100 or 1300 ? to evaluate the crack-healing ability. Microstructural studies showed that cracks in 15 wt% MoSi2 doped Yb2Si2O7 composites were fully healed during annealing at 1300 ?. Two mechanisms may be responsible for crack healing. First, the cracks were filled with SiO2 glass formed by MoSi2 oxidation. Second, the formed SiO2 continued to react with Yb2SiO5 to form Yb2Si2O7 , which can cause cracks to heal owing to volumetric expansion. The Yb2Si2O7 formation with smaller volume expansion is more beneficial.

The organic piezoelectric polymer polyvinylidene fluoride (PVDF) has attracted extensive research because of its excellent flexibility and mechanical energy-harvesting properties. Here, the electrospinning technique was taken to fabricate synthesized fiber membranes of a PVDF/cellulose acetate (CA) composite. The obtained PVDF/CA electrospun fiber membranes (EFMs) were employed to prepare a flexible nanogenerator. XRD and FTIR spectroscopy revealed the enhancement of piezoelectric behavior due to an increase in β-phase in PVDF/CA EFMs compared with cast films. The PVDF/CA fibers (mass ratio of PVDF to CA = 9:1) showed an output voltage of 7.5 V and a short-circuit current of 2.1 μA under mechanical stress of 2 N and frequency of 1 Hz, which were 2.5 and two times greater than those of the pure PVDF fibers, respectively. By charging a 4.7 µF capacitor for 15 min with the voltage generated by the PVDF/CA EFMs, nine LED lamps could be lit. The work provides an effective approach to enhancing the piezoelectric effects of PVDF for low-power electronic loading of macromolecule polymers.

In this study, a high-entropy RMgAl11O19 (HE-RMA, R = La, Pr, Nd, Sm, Gd) and LaMgAl11O19 (LMA) coatings were fabricated by atmospheric plasma spraying. The phase composition, microstructure, thermal stability, infrared emissivity performance and shock resistance were comparatively characterized. The results showed that doping multiple rare-earth cations could be conductive to enhance the infrared emissivity. The as-sprayed HERMA coating exhibited the highest infrared emissivity, which reached up to 0.971 at 1000 degrees C. The reason for the improvement of the infrared emissivity was attributed to introduced impurity energy level resulting from doping cations, which could reduce the forbidden bandwidth and increase probability of electronic transition. Meanwhile, HE-RMA coating exhibited better shock resistance at 1100 degrees C due to superior fracture toughness (1.84 +/- 0.41 MPa.m(1/2)) during thermal cycling test at 1100 degrees C. In addition, HE-RMA coating still exhibited high infrared emissivity (0.932 at 1000 degrees C) at 1100 degrees C annealing for 100 h with only a slight reduction.

Background:Dextro-transposition of the great arteries (D-TGA) is a rare congenital heart disease, as it affects only 0.02-0.05% of live births. It is the second most common cyanotic heart disease following Tetralogy of Fallot. It has a male predominance. Fetal echocardiography is an optimal method for prenatal diagnosis of fetal D-TGA. In twin pregnancies, fetal D-TGA in one twin is very rare, especially in monochorionic-diamniotic twin pregnancies. Herein, we report a case of D-TGA in one twin in two dichorionic-diamniotic twin pregnancies and one monochorionic-diamniotic twin pregnancy from January 2018 to June 2021.Case Description:One twin with D-TGA was diagnosed by fetal echocardiography in the second trimester, and the co-twin was normal in all three cases. A multidisciplinary team provided extensive counseling regarding the D-TGA twin and the co-twin, and adequate perinatal management was provided. In cases 1, 2, and 3, the mothers underwent cesarean sections at 37 weeks + 2 days, 34 weeks + 5 days, and 36 weeks + 1 day, respectively. In case 1, which involved a female D-TGA neonate with birth weight 2,410 g, an emergent atrial septostomy was performed at 20 h after birth, and the neonate underwent atrial switch operation (ASO) 24 days after birth. In case 2, involving a male D-TGA neonate with a birth weight of 2,380 g, ASO was performed 24 days after birth. In case 3, involving a female D-TGA neonate with birth weight 2,240 g, ASO was performed 19 days after birth and delayed sternal closure was performed 4 days later. All six infants showed normal development during follow-up.Conclusions:Early antenatal diagnosis of D-TGA in one fetus of a twin pregnancy is significantly important. A multidisciplinary team should carry individual evaluation and integrated management of the D-TGA twin and co-twin during the pregnancy and perinatal period. After birth, delayed ductus arteriosus closure in the D-TGA twins should be performed when necessary and individualized timings for arterial switch operation should be considered.

Atmospheric plasma spraying (APS) process was employed to produce four-layer Si/Si-Yb2SiO5/Yb2SiO5/LaMgAl11O19 environmental barrier coatings (EBCs) for SiCf/SiC composites with SiC sealing layer. The bending strength of the specimens after isothermal oxidation was investigated. The specimens with EBCs especially thanks to the Si-Yb2SiO5 mixture layer showed a high bending strength retention rate with "psesudo-plastic" fracture. The Si-Yb2SiO5 mixture layer could remarkably enhance the oxidation resistance and also prolonged the life of the EBCs. Such obvious improvements in the Si-Yb2SiO5 mixture layer were attributed to that Yb2SiO5 reacted with TGO (SiO2) to in-situ form a dense Yb2Si2O7 layer, which was conducive to control the thickness of the TGO and prevent the prolongation of the cracks.

In this study, La1-xNdxMgAl11-xScxO19 (x = 0.1, 0.2, 0.3; abbreviated as LNMAS-1, 2, 3) coatings which are supposed to possess better properties than LaMgAl11O19 (LMA) were plasma-sprayed and their high-temperature performance were comparatively investigated. Results show that addition of Nd3+ and Sc3+ as dopants to LMA endows corresponding coatings with reduced thermal conductivity and enhanced thermal expansion coefficient, while maintaining advantageous phase stability, although still being subjected to amorphization in plasma flame and following crystallization upon high-temperature service. Furthermore, the doping could cause adherence increasing between topcoat/bondcoat, benefiting from improved melting condition, especially in LNMAS-2 and LNMAS-3 coatings, which is related to the specific powder morphology and lowered melting point. During exposure to 1350 degrees C, mechanical performance and structure integrity of doped free-standing LNMAS coatings can be well preserved even after 400 h aging. In thermal cyclic fatigue test, LNMAS-2 and LNMAS-3 coatings undertake thermal cycling lifetime of similar to 181 and 191 cycles at 1100 degrees C, respectively, 40% durable than that of LMA coating. These preliminary results suggest that LNMAS-2, 3 might be promising candidates for advanced thermal barrier coating applications.

LaMgAl11O19-type magnetoplumbite holds great promise to be used above 1300 degrees C as thermal barrier coatings (TBCs), but its practical application has been restricted because of inferior thermophysical properties. Herein, we focus on optimizing the thermophysical properties of LaMgAl11O19 by simultaneously substituting La3+ and Al3+ ions with Nd3+ and Sc3+ ions, respectively. Results show that the effects of co-substitution on reducing thermal conductivity are pronounced. The thermal conductivities of La1-xNdxMgAl11-xScxO19 (x = 0, 0.1, 0.2, 0.3) ceramics decrease progressively with dopant concentration and a lowest thermal conductivity of 2.04 W/(m.K) is achieved with x = 0.3 at 1000 degrees C, which is a value superior to pure LMA and even lower than YSZ. The mechanisms behind the lowered thermal conductivity are investigated. Increase of the thermal expansion coefficient is also realized (8.53 x 10(-6) K-1 for pure LMA, 9.07 x 10(-6) K-1 for x = 0.3, 1300 degrees C). Most importantly, Nd3+ and Sc3+ combination doping indeed facilitates mechanical properties of La1-xNdxMgAl11-xScxO19 solid solutions as well. It should be noted that Sc3+ doping at Al3+ site plays more effective role in improving thermal properties than Nd3+ does at La3+ site. This work provides a path to simultaneously integrate low thermal conductivity, good phase stability, moderate thermal expansion behavior and excellent mechanical properties on LMA for the next generation TBCs.

Continuous silicon carbide fiber reinforced silicon carbide (SiCf/SiC) ceramic matrix composites are considered promising materials as high-temperature components of advanced aero-engines. However, due to their susceptibility to oxidation and corrosion at high temperature, environmental barrier coatings (EBCs) must be applied on the surface of SiCf/SiC. In this study, Si/Y2SiO5/LaMgAl11O19 (LMA) multi-layer EBCs were fabricated to protect SiCf/SiC by using atmospheric plasma spraying (APS). The high-temperature tensile fatigue performance of SiCf/SiC with and without EBCs was evaluated. The results indicated that EBCs significantly improved the tensile fatigue properties of SiCf/SiC at high temperature in air atmosphere. Meanwhile the bending strength of specimens after isothermal aging or not was also tested. The multi-layer EBCs in this study may be a promising EBCs system for SiCf/SiC after some improvements.