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With the capability of interconversion between electrical and mechanical energy, piezoelectric materials have been revolutionized by the implementation of perovskite-piezoelectric-ceramic-based studies over 70 years. In particular, the market of piezoelectric ceramics has been dominated by lead zirconate titanate for decades. Nowadays, the research on piezoelectric ceramics is largely driven by cutting-edge technological demand as well as the consideration of a sustainable society. Hence, environmental-friendly lead-free piezoelectric materials have emerged to replace lead-based Pb(Zr,Ti)O3 (PZT) compositions. Owing to the inherent high mechanical quality factor (Qm) and low energy loss, (Li,Na)NbO3 (LNN) materials have recently drawn increasing attention and brought advantages to high-power piezoelectric applications. Although the crystallographic structures of LNN materials were intensively investigated for decades, the technical strategies for electrical performance are still limited. As a result, the property enhancement appears to have approached a plateau. This review traces the progress in the development of LNN materials, starting from the polymorphism in terms of the crystal structures, phase transitions, and local structural distortions. Then, the key milestone works on the functional tunability of LNN are reviewed with emphasis on involved engineering approaches. The exceptional performance at a large vibration velocity makes LNN ceramics promising for high-power applications, such as ultrasonic welding (UW) and ultrasonic osteotomes (UOs). The remaining challenges and some strategic insights for synergistically engineering the functional performance of LNN piezoceramics are also suggested.

With the rapid development of mobile services, big data, cloud services, and artificial intelligence, traditional network services cannot no longer meet the requirements of current network development and solve the problems of the resource allocation and scheduling ossification in the current network. Therefore, by using network virtualization technologies, we can provide the flexible network resource configuration information for users to reduce network cost and improve network resource efficiency. The required bandwidth resources of each virtual link are divided into different transmission line rate by employing mixed line rate splitting. We propose an optimized cost approach for Virtual Optical Network (VON) mapping based on mixed line rate. Simulation results show that the proposed optimized cost approach of VON mapping based on mixed line rate can achieve better optimization and balance in terms of the network cost, frequency slot occupation, the configuration of optical transponders, and optical regenerators.

With the development of big data, cloud services, and artificial intelligence, the optical network is developing towards scale and complexity, which suffers from larger probability of network failure. It is necessary to provide dedicated-path protection for each connection request to reduce the loss caused by the network failures. Therefore, in order to guarantee the network survivability, we propose a dedicated-path protection optimization method to improve the network resource efficiency in elastic optical networks with data centers. The simulation results show that the proposed dedicated-path protection optimization method can effectively reduce the blocking probability, improve the network resource utilization, and solve the survivability problem of elastic optical networks in data centers.

Abstract Domain engineering in ferroelectrics endows flexibility for different functional applications. Whereas the domain engineering strategy for single crystals and thin films is diverse, there is only a limited number of strategies for bulk ceramics. Here, a domain engineering strategy for achieving a compact domain architecture with increased domain‐wall density in (K,Na)NbO3 (KNN)‐based ferroelectric ceramics via mesoscopic chemical inhomogeneity (MCI) is developed. The MCI‐induced interfaces can effectively hinder domain continuity and modify the domain configuration. Besides, the MCI effect also results in diffused phase transitions, which is beneficial for achieving enhanced thermal stability. Modulation of chemical inhomogeneity demonstrates great potential for engineering desirable domain configuration and properties in ferroelectric ceramics. Additionally, the MCI can be easily controlled by regulating the processing condition during solid‐state synthesis, which is advantageous to industrial production.

Aiming at the problems of ground settlement induced by the underground pipeline damage in water-rich sand layer, a set of visualization experimental device was designed. For these cases of 11 kinds of sand samples with particle size of soil d90=1.458.45mm and 5 kinds of full pipe flow velocity, the behavior of ground settlement induced by seepage erosion was studied. Research showed that:（1）There are three modes of seepage erosion induced by pipeline damage: only water inrush without settlement, soil arching formation with settlement, and sand crushing with settlement;（2）The particle size of soil , damaged mouth size and thick-span ratio are the main factors determining the seepage erosion mode of soil;（3）When the soil arching or sand crushing is formed in the soil above the damaged mouth of pipeline, the relationship between the particle size of soil d90 and the thick-span ratio r is that: when 8.0≥r≥4.2, the d90 decreases parabolically with the increase of r; when 12.5≥r≥8.0, d90 remains unchanged;（4）When the soil arching or sand crushing is formed in the soil above the damaged mouth of pipeline, the initial settlement radius and settlement depth with the flow velocity of 0 are determined by the ratio (D/d50) of the damaged mouth diameter D and the average particle size of soil d50 ; the settlement radius and depth increase linearly with the increase of full pipe flow velocity; when the soil arching is formed, the expansion velocity （VL、VH） of settlement radius and settlement depth with the increase of flow velocity is logarithmic to D/d50; When the sand crushing is formed, the expansion velocity VL of settlement radius with the increase of flow velocity is that, when 23.0≥D/d50≥6.0, it increases linearly with the increase of D/d50; when 42.0≥D/d50≥23.0, it decreases logarithmically with the increase of D/d50.

Although piezocatalysis has achieved preliminary achievements in environmental remediation and biomedical applications, large‐scale fabrication of piezocatalysts with high degradation efficiency and low cost remains challenging. In this work, a new and easy strategy to solve this challenge is innovatively proposed, that is, ceramic‐powder‐driven boosted polarization intensity, and validated the strategy is by examining potassium sodium niobate ((K, Na)NbO3, KNN) ferroelectric. KNN‐3 piezocatalyst, obtained by grinding as‐sintered ceramics into powder, shows a degradation rate (k) as high as 148 × 10−3 min−1 for rhodamine B (RhB) dye and for 31 × 10−3 min−1 for methyl orange (MO) dye, ≈18 times and 66 times than those of previously reported KNN piezocatalysts. The superior piezocatalytic activity is attributed to enhanced polarization intensity, increased oxygen vacancies, and higher charge carrier concentrations. Besides, the KNN‐3 piezocatalyst shows excellent inhibitory effects on Staphylococcus aureus and Escherichia coli strains. Therefore, the proven ceramic preparation technology enables the new strategy to mass produce high‐performance KNN piezocatalysts that hold promise for applications in dye degradation and biomedicine. [ABSTRACT FROM AUTHOR]

With increasing concerns about noise pollution, the pursuit of highly dependable piezoelectric acoustic sensors for real‐time noise monitoring has come to the forefront of scientific research. Lead‐based perovskite piezoelectric films, exemplified by lead zirconate titanate Pb(Zr,Ti)O3 (PZT), surpass traditional piezoelectric materials such as ZnO and AlN in their piezoelectric properties, promising substantial advancements in next‐generation acoustic sensor technologies. However, the toxic nature of lead in PZT materials poses formidable environmental and human health risks. In an unprecedented breakthrough, it presents the pioneering development of an environmentally benign lead‐free piezoelectric Micro‐Electro‐Mechanical System (MEMS) acoustic sensor based on potassium sodium niobate (K,Na)NbO3 (KNN) film. High‐quality <001> textured 3 µm‐thick KNN film is successfully integrated into commercially used Si substrate, rendering exceptional piezoelectricity (transverse piezoelectric coefficients e31* of ≈8.5 C m−2) with satisfactory thermal stability. The atomic‐scale Z‐contrast imaging and piezoresponse force microscopy characterizations reveal that the outstanding piezoresponse originates from the local coexistence of multiple phases and the enhancement of extrinsic piezoelectric contributions from in‐plane polarization anisotropy. Finite element simulation is employed to design the triangular cantilever structure and annular diaphragm structure, each corresponding to different operating bandwidths. The resultant MEMS acoustic sensors stand out with outstanding acoustic performance (the high sensitivity and expansive receiving field of view), which are attributed to the microstructural engineering at multi‐length scales for the excellent piezoelectric properties of KNN film. These features enable sensitive acoustic monitoring in various environments, including large‐scale power grids and urban traffic. [ABSTRACT FROM AUTHOR]

Background: To investigate the efficacy and safety of endoscopic electrocoagulation haemostasis via a percutaneous transhepatic approach for the treatment of grade IV haemorrhagic cystitis (HC) after allogeneic haematopoietic stem cell transplantation (allo-HSCT) in children. Methods: The clinical data of 14 children with severe HC, who were admitted to Hebei Yanda Hospital between July 2017 and January 2020, were analysed retrospectively. There were nine males and five females, with an average age of 8.6 years (range: 3 to 13 years). After an average of 39.6 (7 to 96) days of conservative treatment in the hospital's haematology department, the bladders of all patients were filled with blood clots. A small 2-cm incision was made in the suprapubic area to enter the bladder and quickly clear the blood clots, and a percutaneous transhepatic approach to electrocoagulation and haemostasis was performed. Results: In the 14 children, a total of 16 operations were performed, with an average operation time of 97.1 (31 to 150) min, an average blood clot of 128.1 (80 to 460) mL and an average intraoperative blood loss of 31.9 (20 to 50) mL. There were three cases of postoperative bladder spasm remission after conservative treatment. During the follow-up period of 1 to 31 months, one patient improved after one operation, 11 patients were cured after one operation, and two patients were cured after recurrent haemostasis by secondary electrocoagulation, four of whom died of postoperative non-surgical blood-related diseases and severe lung infections. Conclusion: Percutaneous electrocoagulation haemostasis can quickly remove blood clots in the bladders of children after allo-HSCT with grade IV HC. It is a safe and effective minimally invasive treatment. [ABSTRACT FROM AUTHOR]