21 research outputs found
Accurate piezoelectric tensor prediction with equivariant attention tensor graph neural network
No full textAbstract The piezoelectric materials enable the mutual conversion between mechanical and electrical energy, which drive a multi-billion dollar industry through their applications as sensors, actuators, and energy harvesters. The third-rank piezoelectric tensor is the core matrices for piezoelectric materials and their devices. However, the high costs of obtaining full piezoelectric tensor data through either experimental or computational methods make a significant challenge. Here, we propose an equivariant attention tensor graph neural network (EATGNN) that can identify crystal symmetry and remain independent of the reference frame, ultimately enabling the accurate prediction of the complete third-rank piezoelectric tensor. Especially, we perform an irreducible decomposition of the piezoelectric tensor into four irreducible representations to efficiently reserve the symmetry under group transformation operations. Our results further demonstrate that this model performs well in both bulk and two-dimensional materials. Finally, combining EATGNN with first-principles calculations, we discovered several potential high-performance piezoelectric materials
SNHG19 promotes the proliferation and metastasis of hepatocellular carcinoma through regulating the miR-137/protein tyrosine phosphatase 4A3 axis
No full textObjectives: Long noncoding RNAs plays the important part in tumor biology. SNHG19 was found to be a new oncogenic lncRNA in some malignant tumors. However, the effect of SNHG19 in hepatocellular carcinoma has not been reported. Methods: The expression of SNHG19 in hepatocellular carcinoma tissues were detected by using quantitative Real-Time Reverse Transcription Polymerase Chain Reaction (qRT-PCR). Melanoma cases from The Cancer Genome Atlas were included in this study. cell counting kit-8 assay, Transwell, and scratch wound assay were used to explore the role of SNHG19 in melanoma cells. Luciferase reporter assays and RNA pull-down assay were used to explore the molecular mechanism of SNHG19 in hepatocellular carcinoma. Results: Here, we found that SNHG19 level was upregulated in hepatocellular carcinoma. Hepatocellular carcinoma patients with high levels of SNHG19 have shorter Disease-Free Survival (RFS). SNHG19 promotes the Protein Tyrosine Phosphatase 4A3 expression by sponging miR-137 to liberate Protein Tyrosine Phosphatase 4A3 mRNA transcripts. SNHG19 enhances the development of hepatocellular carcinoma by affecting miR-137/Protein Tyrosine Phosphatase 4A3 axis. Conclusion: These results demonstrated the effect of SNHG19 in the occurrence and progression of hepatocellular carcinoma. SNHG19 may be used as the specific molecular target in patients with hepatocellular carcinoma
Achieve a high electrochemical oxidation activity by a self-assembled cermet composite anode with low Ni content for solid oxide fuel cells
No full textFunding Information: The financial support from the National Natural Science Foundation of China under contract number 22075205 and the support of Tianjin Municipal Science and Technology Commission under contract number 19JCYBJC21700 are gratefully acknowledged. The work has been also supported by the Program of Introducing Talents to the University Disciplines under file number B06006, and the Program for Changjiang Scholars and Innovative Research Teams in Universities under file number IRT 0641. Publisher Copyright: © 2023, The Author(s), under exclusive licence to Springer-Verlag GmbH Germany, part of Springer Nature.Ni-based cermets are the most widely used anode materials for solid oxide fuel cells. Reducing the content of Ni is beneficial to anode stability but usually unfavorable for the catalytic activity. In this study, Ni-Ce0.8Sm0.2O2-δ anode with a low Ni content is synthesized through a polymer-directed evaporation-induced self-assembly strategy. Ni distributes evenly in the anode, resulting in an enlarged triple-phase boundary region and improved reactivity of lattice oxygen in the oxide phase. The anode containing 5 wt.% Ni possesses the highest amounts of oxygen vacancies and Ce3+/Ce4+ redox pairs that facilitates the charge transfer process, which is one of the rate-determining steps of anode reaction. Consequently, that anode shows the lowest polarization resistance of 0.014 Ω cm2 at 700 °C, much lower than those of other Ni-based anodes prepared through conventional techniques such as impregnation and solid-mixing. With that anode, a single cell supported by a 480-μm-thick Ce0.8Sm0.2O2-δ electrolyte layer exhibits the maximum power density of 270 mW cm−2 at 700 °C. The anode also shows a promising stability.Peer reviewe
Self-assembled La0.7Sr0.3Fe0.9Ni0.1O3-δ-Ce0.8Sm0.2O2-δ composite cathode with a three-dimensional ordered macroporous structure for protonic ceramic fuel cells
No full textPublisher Copyright: © 2024 Elsevier B.V.Self-assembled La0.7Sr0.3Fe0.9Ni0.1O3-δ-Ce0.8Sm0.2O1.9-δ (LSFN-SDC) composite cathode with a three-dimensionally ordered macroporous (3DOM) structure is synthesized using poly(methyl methacrylate) as the template for protonic ceramic fuel cells. The LSFN and SDC phases both distribute uniformly in the cathode. The SDC phase reduces the thickness of the walls of the 3DOM structure and thus hinders the bulk conduction of electrons. SDC also decreases the specific surface area and the surface oxygen reactivity of the cathode, leading to the suppression of the adsorption and dissociation of O2. However, the SDC phase provides the conduction pathway for oxygen ions and enlarges three phase boundary consequently, which facilitates the charge transfer steps. The thickness of the walls and the specific surface area of the composite cathode are both increased with the rise of the concentration of the nitrate precursor solution, resulting in the acceleration of the cathode process. Nevertheless, an excessive precursor concentration leads to the destroy of the 3DOM structure. The 3DOM composite cathode exhibits the lowest Rp of 0.039 Ω cm2, and a single cell with that cathode shows maximum power density of 1484 mW cm−2 at 700 °C. The cell exhibits a short-term stability of 120 h at 700 °C without noticeable degradation.Peer reviewe
A cobalt-free Pr6O11–BaCe0.2Fe0.8O3-δ composite cathode for protonic ceramic fuel cells with promising oxygen reduction activity and hydration ability
No full textPublisher Copyright: © 2024 Elsevier B.V.Oxygen reduction and proton conduction originated from hydration are two key steps in the cathode process of protonic ceramic fuel cells. In this work, Pr6O11 is impregnated into a cobalt-free BaCe0.2Fe0.8O3-δ cathode, resulting in an improved activity of lattice oxygen and a moderate enhancement of the electrical conductivity, both of which are beneficial for charge transfer, the rate-determining step of oxygen reduction process at the cathode. The polarization resistance of bare BaCe0.2Fe0.8O3-δ cathode for oxygen reduction is 0.115 Ω cm2 at 700 °C, which is reduced significantly to 0.039 Ω cm2 with the addition of 30 wt% Pr6O11. Besides, the hydration ability of the cathode is also improved with Pr6O11, and thus the combination of proton and oxygen is facilitated. A single cell with 30 wt% Pr6O11-70 wt% BaCe0.2Fe0.8O3-δ composite cathode exhibits the highest maximum power density of 1406 mW cm−2 at 700 °C. The composite cathode also shows a good stability.Peer reviewe
Amino Acid-Induced Interface Charge Engineering Enables Highly Reversible Zn Anode
No full textDespite the impressive merits of low-cost and high-safety electrochemical energy storage for aqueous zinc ion batteries, researchers have long struggled against the unresolved issues of dendrite growth and the side reactions of zinc metal anodes. Herein, a new strategy of zinc-electrolyte interface charge engineering induced by amino acid additives is demonstrated for highly reversible zinc plating/stripping. Through electrostatic preferential absorption of positively charged arginine molecules on the surface of the zinc metal anode, a self-adaptive zinc-electrolyte interface is established for the inhibition of water adsorption/hydrogen evolution and the guidance of uniform zinc deposition. Consequently, an ultra-long stable cycling up to 2200 h at a high current density of 5 mA cm−2 is achieved under an areal capacity of 4 mAh cm−2. Even cycled at an ultra-high current density of 10 mA cm−2, 900 h-long stable cycling is still demonstrated, demonstrating the reliable self-adaptive feature of the zinc-electrolyte interface. This work provides a new perspective of interface charge engineering in realizing highly reversible bulk zinc anode that can prompt its practical application in aqueous rechargeable zinc batteries
Self-assembled La0.6Sr0.4FeO3-δ-La1.2Sr0.8NiO4+δ composite cathode for protonic ceramic fuel cells
No full textFunding Information: The financial support from National Natural Science Foundation of China under contract number 22075205 and the support of Tianjin Municipal Science and Technology Commission under contract number 19JCYBJC21700 are gratefully acknowledged. The work has been also supported by the Program of Introducing Talents to the University Disciplines under file number B06006 , and the Program for Changjiang Scholars and Innovative Research Teams in Universities under file number IRT 0641 . Publisher Copyright: © 2023 Elsevier Ltd and Techna Group S.r.l.The oxygen reduction reaction at the cathode is an essential process for protonic ceramic fuel cells. Composite cathode materials are commonly used towards the multiple requirements including high surface oxygen activity as well as sufficient electronic and ionic conductivities. In this study, a cobalt-free composite cathode composed of a perovskite La0.6Sr0.4FeO3-δ phase and a Ruddlesden-Popper La1.2Sr0.8NiO4+δ phase is synthesized with a self-assembly technology. The cathode process is mainly controlled by (I) the reduction of adsorbed oxygen atom to O− on the surface and (II) the migration of O− from the surface into the lattice. The former benefits from the high electrical conductivity of La0.6Sr0.4FeO3-δ, and the latter is accelerated by La1.2Sr0.8NiO4+δ attributed to its superior oxygen activity. The one-pot synthesized composite cathode shows an enhanced synergistic effect due to the uniform distribution of the two phases at the nanoscale. The cathode shows the lowest polarization resistances of 0.055 and 0.095 Ω cm2 at 700 °C in oxygen and air, respectively. The results show that self-assembled La0.6Sr0.4FeO3-δ-La1.2Sr0.8NiO4+δ nanocomposite is a promising cathode material for protonic ceramic fuel cells.Peer reviewe
Performance Degradation Prediction Using LSTM with Optimized Parameters
No full textPredicting the degradation of mechanical components, such as rolling bearings is critical to the proper monitoring of the condition of mechanical equipment. A new method, based on a long short-term memory network (LSTM) algorithm, has been developed to improve the accuracy of degradation prediction. The model parameters are optimized via improved particle swarm optimization (IPSO). Regarding how this applies to the rolling bearings, firstly, multi-dimension feature parameters are extracted from the bearing’s vibration signals and fused into responsive features by using the kernel joint approximate diagonalization of eigen-matrices (KJADE) method. Then, the between-class and within-class scatter (SS) are calculated to develop performance degradation indicators. Since network model parameters influence the predictive accuracy of the LSTM model, an IPSO algorithm is used to obtain the optimal prediction model via the LSTM model parameters’ optimization. Finally, the LSTM model, with said optimal parameters, was used to predict the degradation trend of the bearing’s performance. The experiment’s results show that the proposed method can effectively identify the trends of degradation and performance. Moreover, the predictive accuracy of this proposed method is greater than that of the extreme learning machine (ELM) and support vector regression (SVR), which are the algorithms conventionally used in degradation modeling
Giant Bandgap Engineering in Two-Dimensional Ferroelectric α‑In<sub>2</sub>Se<sub>3</sub>
No full textBandgap
engineering is an efficient strategy for controlling the
physical properties of semiconductor materials. For flexible two-dimensional
(2D) materials, strain provides a nondestructive and adjustable method
for bandgap adjustment. Here, we propose that, in 2D materials with
out-of-plane ferroelectricity, the antibonding nature of the valence
band maximum and conduction band minimum and polarized charge distribution
induced by ferroelectricity give rise to giant changes of the bandgap
under curvature strain field. This hypothesis was proven by scanning
tunneling microscopy/spectroscopy measurements on monolayer α-In2Se3 that revealed that the bandgap of α-In2Se3 increases significantly due to bending. Both
experiments and theoretical calculations indicated that the bandgap
increases monotonically with the degree of bending of the α-In2Se3 layer. Our work suggests that bending is an
effective method for tuning the gaps of 2D ferroelectric materials,
providing a new platform for bandgap engineering under the combination
of ferroelectricity and strain field
Designing Ultra-flat Bands in Twisted Bilayer Materials at Large Twist Angles: Theory and Application to Two-Dimensional Indium Selenide
No full textIntertwisted bilayers of two-dimensional
(2D) materials can host
low-energy flat bands, which offer opportunity to investigate many
intriguing physics associated with strong electron correlations. In
the existing systems, ultra-flat bands only emerge at very small twist
angles less than a few degrees, which poses a challenge for experimental
studies and practical applications. Here, we propose a new design
principle to achieve low-energy ultra-flat bands with increased twist
angles. The key condition is to have a 2D semiconducting material
with a large energy difference of band edges controlled by stacking.
We show that the interlayer interaction leads to defect-like states
under twisting, which forms a flat band in the semiconducting band
gap with dispersion strongly suppressed by the large energy barriers
in the moiré superlattice even for large twist angles. We explicitly
demonstrate our idea in bilayer α-In2Se3 and bilayer InSe. For bilayer α-In2Se3, we show that a twist angle of ∼13.2° is sufficient
to achieve the band flatness comparable to that of twist bilayer graphene
at the magic angle ∼1.1°. In addition, the appearance
of ultra-flat bands here is not sensitive to the twist angle as in
bilayer graphene, and it can be further controlled by external gate
fields. Our finding provides a new route to achieve ultra-flat bands
other than reducing the twist angles and paves the way toward engineering
such flat bands in a large family of 2D materials
