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To address the issue of excessive transient noise during the opening and closing of a sea valve, a method for reducing pressure fluctuations during the opening of the electromagnetic hydraulic distributor has been proposed by analyzing the structure and working principle of the distributor. Based on theoretical calculation and simulation analysis, the size and shape of the buffer slot of the flow hole are determined under the condition that the stable working flow rate remains unchanged. An improved electromagnetic hydraulic distributor is developed and tested. The results indicate that this method can effectively control the opening and closing transient noise of the sea valve. [ABSTRACT FROM AUTHOR]

In order to obtain novel and more efficient red light‐emitting materials, a series of Sr2[Mg1−xLixAl5−xSixN7] : 0.01Eu2+ (SMAN‐xLS, 0≤x≤0.5) red phosphors were devised and successfully synthesized via the high temperature solid state reaction and the effects of the co‐substitution of [Mg−Al]5+ by [Li−Si]5+ on structural and luminescence properties is investigated in detail. A series of powder XRD data and Rietveld refinement indicate that [Li−Si]5+ co‐substitution can successfully enter the Sr2[MgAl5N7] : 0.01Eu2+ (SMAN) lattice. With the entry of [Li−Si]5+ into the lattice, the substitution of Al3+ by Si4+ leads to the weakening of the nephelauxetic effect of the 5d level of Eu2+, which shifts the emission peak from 657 nm to 647 nm and reduces the excitation in the green region, i.e., lowers the absorption of green light. When the amount of [Li−Si]5+ co‐substitution is x=0.1, the luminescence intensity and thermal stability of the sample are enhanced, in which the external quantum efficiency (EQE), reflecting the luminescence intensity, is elevated by 49.6 %. The increase in lattice rigidity gives rise to higher luminescence intensity, and the introduced trap levels for the compensation of luminescence enhances the thermal stability. Under blue laser excitation, the SMAN‐0.1LS can achieve an ultra‐high luminescence saturation threshold of 52.22 W/mm2, which is remarkably superior to other existing red phosphors, a breakthrough performance that has enormous potential for application in high‐power laser display light sources. Cathodoluminescence (CL) characterization and measurements attest to the favorable CL properties of SMAN‐0.1LS. By measuring the pressure‐dependent luminescence of SMAN‐0.1LS, the emission peak can be shifted from 650 nm to 702 nm with the increase of pressure, and the sensitivity dλ/dP is 5.07 nm/GPa, which is indicative of the potential application of this system as an optical pressure sensor. [ABSTRACT FROM AUTHOR]

Two-dimensional (2D) materials are one of the research frontiers in material science due to their promising properties. Chemical Vapor Deposition (CVD) is the most widely used technique to grow large-scale high-quality 2D materials. The CVD-grown 2D materials can be efficiently characterized by an optical microscope. However, annotating microscopy images to distinguish the growth quality from good to bad is time-consuming. In this work, we explore Active Learning (AL), which iteratively acquires quality labels from a human and updates the classifier for microscopy images. As a result, AL only requires a limited amount of labels to achieve a good model performance. However, the existing handcrafted query strategies in AL are not good at dealing with the dynamics during the query process since the rigid handcrafted query strategies may not be able to choose the most informative instances (i.e., images) after each query. We propose a Reinforced Active Learning (RAL) framework that uses reinforcement learning to learn a query strategy for AL. Besides, by introducing the intrinsic motivation into the proposed framework, a unique intrinsic reward is designed to enhance the classification performance. The results show that RAL outperforms AL, and can significantly reduce the annotation efforts for the CVD-grown 2D materials characterization. [ABSTRACT FROM AUTHOR]

Energy storage batteries still have usable capacity after retirement, with excellent secondary utilization value. Estimating the state of health (SOH) of retired batteries is critical to ensure their reuse. As the battery first reaches the end of its useful life, its performance degradation pattern significantly differs from that in service, increasing the difficulty of accurate SOH estimation. This study developed a SOH estimation method for retired batteries based on battery positive, negative, and center temperature data from 80% to 50% of retired battery health. The variational mode decomposition technique divides the temperature signal into multiple trends representing different battery aging mechanisms. The decomposed modes are given a physical meaningfulness, providing a new perspective to monitor battery health. In addition, this study proposes a multi-task learning framework that realizes the parallel processing of two tasks under this framework. On the one hand, the gated recurrent unit is used to estimate the relationship between the battery baseline temperature and SOH, which captures macro-degradation trends of the battery. On the other hand, the transformer network is responsible for analyzing short-term battery health fluctuations caused by subtle temperature changes. This multi-task approach can simultaneously process and analyze both macro-degradation trends and micro-fluctuations in battery degradation, estimating that the root mean square error of battery health is 5.22 × 10−5. Compared to the existing techniques, this study shows potential applications in the retired battery state of health assessment. [ABSTRACT FROM AUTHOR]

To solve the problem of thermal stability of the red‐emitting phosphor Sr2Si5N8:Eu2+ with great valuable luminescence performance, trivalent rare earth ions Ln3+ (Ln = Dy, Ho, Er, Tm, Nd, and Pr) are co‐doped into Sr2Si5N8: Eu2+ lattice to form thermally robust phosphors Sr2Si5N8:Eu2+,xLn3+(Lnx‐258, 0 ≤ x ≤ 0.05). The successful incorporation of rare earth ions in the crystal structure and the regulation of luminescent properties are proven by a variety of material characterization techniques and analysis. Although the co‐doping of the selected rare earth ions reduces the luminescence intensity of the phosphor, the Dy0.01‐258 sample still has a high external quantum efficiency (EQE) of 78.6%. More importantly, the co‐doping of Dy3+ with x = 0.01 significantly improves the luminescent thermal stability of phosphors at high temperature and the luminescence intensity of Dy0.01‐258 samples at 200 °C can be maintained at 94.7% of room temperature. The thermoluminescence spectrum shows that the defects brought about by co‐doping of Dy3+ with x = 0.01 introduce trap energy levels, which can compensate for the Eu2+ luminescence at high temperature. At the same time, the cathodoluminescence mapping and spectra show that the phosphor has a high saturation current under high‐energy electron bombardment, which indicates that this nitride phosphor also has the potential to be used in field emission display (FEDs). Based on its extraordinary EQE and thermal stability data, this nitride phosphor is the first‐rate among the red phosphors for pc‐wLEDs, and has excellent application prospects in FEDs. [ABSTRACT FROM AUTHOR]

The epitaxial growth of high‐quality and large‐area monolayer (ML) MoS2 has attracted widespread attention in recent years. Here, MoS2 on Al2O3 substrate was prepared by using atmospheric‐pressure chemical vapor deposition. The process parameters such as temperature difference and distance between MoO3 and Al2O3, nucleation temperature, and heating rate were optimized. The high MoO3 evaporation temperature facilitates Mo vapor transport to grow ML‐MoS2. The introduction of nucleation temperature facilitates the deposition of MoS2, and the morphology of the nucleation point is related to the amount of MoO3‐x deposited on Al2O3. This process optimization method is also applicable to growth MoS2 on SiO2. The ML‐MoS2 with a size greater than 1 cm2 was successfully fabricated on Al2O3 and SiO2, which laid a foundation for the practical application of ML‐MoS2. [ABSTRACT FROM AUTHOR]

Phosphor‐converted white light‐emitting diodes (pc–WLEDs) realized by combining near‐ultraviolet (NUV) chips and multi‐color phosphors are found to be an effective solution to make up the shortcomings of the poor color rendering index and high correlated color temperature of the combination of blue InGaN chips with YAG:Ce3+ yellow phosphor. However, the NUV excited phosphors suffer from deficiencies such as reabsorption and dissonance deterioration rates. To surmount the drawback above, the ion substitution engineering was carried out to the (Rb,K)2CaPO4F:Eu2+ phosphors, and an NUV excited ultra‐broadband yellow‐emitting phosphor was obtained in this work. With the substitution of Mg2+ for Ca2+, the emission intensities of (Rb,K)2CaPO4F:Eu2+ phosphors are significantly improved as well as the thermal stability. Under the excitation of 380 nm, the yellow phosphor KRbCa0.78Mg0.2PO4F:0.02Eu2+ exhibits an ultra‐broad emission band covering the range from 450 to 800 nm with an amazing FWHM of 181 nm. White light with a super‐high color rendering index (Ra = 92.3), appropriate correlated color temperature (5644 K), as well as stable CIE chromaticity coordinates are achieved by the white light‐emitting diodes device fabricated with this yellow phosphor. These excellent performances indicate that KRbCa0.78Mg0.2PO4F:0.02Eu2+ has great potential to be applicated in the NUV excited white LEDs. [ABSTRACT FROM AUTHOR]

Herein, we provide an overview of the history of research on industrial LED phosphors, focusing on Sr2Si5N8:Eu, which was the first reported nitride phosphor but it is not ideal for industrial LED lighting and displays. While it had desirable red emission and blue excitation properties for LED devices, its thermal stability and working durability were initially poor. The next significant concept appeared during the research on M2Si5N8:Eu for more than 20 years. Understanding photoionization, one of the mechanisms for thermal quenching, has deepened with the new concepts of "trap center-assisted improvement of thermal stability", "europium-trapped exciton", which makes the excited electron return from the trap center to the 5d band of europium, "PL intensity induced by the modification of the energy distance between the conduction band and the trap center or the 5d band of Eu2+", etc. Understanding the non-emissive process in the configurational coordinate model (jumping of excited electron over the crossing point between the two excitation and ground state curves), as another mechanism for thermal quenching, has also deepened with the new concepts of "cation disorder-assisted improvement of thermal stability", "size balance between covalent and ionic parts", "relation between the number of coordination of N3− to Si4+ and the structural stability of host crystal or Eu–N bond", etc. For more than 20 years, the composition of Sr2Si5N8:Eu has been successfully modified to (Sr,Ba)2Si5N8:Eu, and then (Ba,Ca,Sr)2Si5N8:Eu and (Sr,Ba)2(Al,Si)5(N,O)8:Eu having better thermal stability. The above-mentioned fundamental research for clarifying mechanism and finding phenomena is considered to have contributed to the successful industrialization of the 2-5-8 group for LED lighting and displays. [ABSTRACT FROM AUTHOR]