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1.
Kai Liu Chenyang Zhou Jiaming Hu Song Zhang Qingqing Zhang Ce Sun Yusheng Shi Huajun Sun Changxia Yin Yuzhen Zhang Yu Fu 《Journal of the European Ceramic Society》2021,41(12):5909-5917
A digital light processing (DLP) technology has been developed for 3D printing lead-free barium titanate (BTO) piezoelectric ceramics. By comparing the curing and rheological properties of slurries with different photosensitive monomer, a high refractive index monomer acryloyl morpholine (ACMO) was chosen, and a design and preparation method of BTO slurry with high solid content, low viscosity and high curing ability was proposed. By further selecting the printing parameters, the single-layer exposure time was reduced and the forming efficiency has been greatly improved. Sintered specimens were obtained after a nitrogen-air double-step debinding and furnace sintering process, and the BTO ceramics fabricated with 80 wt% slurry shows the highest relative density (95.32 %) and piezoelectric constant (168.1 pC/N). Furthermore, complex-structured BTO ceramics were prepared, impregnated by epoxy resin and finally assembly made into hydrophones, which has significance for the future design and manufacture of piezoelectric ceramic-based composites that used in functional devices. 相似文献
2.
Chenhui Ding Marion Breunig Jana Timm Roland Marschall Jürgen Senker Seema Agarwal 《Advanced functional materials》2021,31(49):2106507
Covalent organic frameworks (COFs) show advantageous characteristics, such as an ordered pore structure and a large surface area for gas storage and separation, energy storage, catalysis, and molecular separation. However, COFs usually exist as difficult-to-process powders, and preparing continuous, robust, flexible, foldable, and rollable COF membranes is still a challenge. Herein, such COF membranes with fiber morphology for the first time prepared via a newly introduced template-assisted framework process are reported. This method uses electrospun porous polymer membranes as a sacrificial large dimension template for making self-standing COF membranes. The porous COF fiber membranes, besides having high crystallinity, also show a large surface area (1153 m2 g−1), good mechanical stability, excellent thermal stability, and flexibility. This study opens up the possibility of preparation of large dimension COF membranes and their derivatives in a simple way and hence shows promise in technical applications in separation, catalysis, and energy in the future. 相似文献
3.
Recently, the successful synthesis of wafer-scale single-crystal graphene, hexagonal boron nitride (hBN), and MoS2 on transition metal surfaces with step edges boosted the research interests in synthesizing wafer-scale 2D single crystals on high-index substrate surfaces. Here, using hBN growth on high-index Cu surfaces as an example, a systematic theoretical study to understand the epitaxial growth of 2D materials on various high-index surfaces is performed. It is revealed that hBN orientation on a high-index surface is highly dependent on the alignment of the step edges of the surface as well as the surface roughness. On an ideal high-index surface, well-aligned hBN islands can be easily achieved, whereas curved step edges on a rough surface can lead to the alignment of hBN along with different directions. This study shows that high-index surfaces with a large step density are robust for templating the epitaxial growth of 2D single crystals due to their large tolerance for surface roughness and provides a general guideline for the epitaxial growth of various 2D single crystals. 相似文献
5.
The exploitation of recycled carbonaceous catalysts from renewable biomass resources such as chitin is a crucial issue for the development of the sustainable society. In this article, the chitin-based N and O doped carbon microspheres (ChC) were fabricated by a simple dissolution, sol–gel transformation, and the carbonization methods. Subsequently, the novel magnetic Ag-Fe3O4@chitin-based carbon microspheres catalyst (MChC) was successfully constructed through the in situ redox reaction. The as-prepared MChC possessed rich micropores with high-surface area, and a narrow size distribution (50–120 μm). The Ag-Fe3O4 nanoparticles were immobilized through the interaction with C, N, and O atoms in the pores of MChC. The reduction of 4-nitrophenol was applied to evaluate the catalytic activity of MChC. 4-Nitrophenol (4-NP) could be fully reduced to 4-aminophenol (4-AP) in 5 min with the catalyst MChC-45. Moreover, MChC could be collected in solution with an external magnet in 8 s and remained relatively high-catalytic activity after 10 cycle times. This work provided novel ideas for the fabrication of doped carbon material from biomass and promoted its utilization in nanocatalytic applications. 相似文献
6.
Nengbing Long Yanqing Fu Tianxiang Xu Dashuang Ding Shaoqian Zhang Shengzhi Sun Shiliang Kang Tiefeng Xu Shixun Dai Qiuhua Nie Changgui Lin 《Journal of the European Ceramic Society》2021,41(8):4584-4589
The confinement of CsPbX3 (X = Cl, Br, and I) perovskite nanocrystals (NCs) in a stabilized inorganic glass matrix is a new strategy for improving their long-term stability and promoting their applications in the optoelectronic field. Here, in situ nanocrystallization strategy is developed to precipitate CsPbBr3?xIx NCs with arbitrary I/Br ratio among an elaborately designed GeS2–Sb2S3-based chalcogenide glass matrix. Spherical CsPbBr3?xIx NCs are homogeneously distributed in the glass matrix after thermal treatment. The photoluminescence (PL) spectra show that the emission peaks of CsPbBr3?xIx NCs can be tuned from 570 nm to 722 nm with the replacement of Br by I. The fs transient absorption (TA) spectra reveal that there exists some structural defects in the NCs, leading to short PL decay life. This work would shed light on confining CsPbX3 NCs into glassy matrices, facilitating their future applications in photoelectronic fields. 相似文献
7.
Juan Ding Yong He Shenhe Fu Xiangsheng Xie Haowen Liang Jianying Zhou 《Journal of the Society for Information Display》2022,30(2):159-167
Illumination is essential for modern life as colorful world is perceived by human visionary system. Display technology has been developing rapidly in recent decades, and the basic principle is related to the way that the image is illuminated and light is emanated. Traditional illumination is provided by different types of light sources, and the display image is visible in large viewing space until the emanating light decays to zero. This work proposes and demonstrates a novel illumination scheme for a display in which the displaying images are visible only in specific spatial regions. The directional backlight ensures the image propagating to specific direction while imaging visibility can be controlled to terminate abruptly at certain distance from the display screen while exerting no influence to nearby regions. The working principle for such an illumination scheme is the use of the modulated coherent directional backlight through an axicon lens. It is shown that the illumination scheme can robustly deliver carried image information to the designated viewing region. This new illumination scheme has many advantages over conventional illumination, including its usage for personal display, very lower energy consumption, as well as minimizing light hazard pollution. 相似文献
8.
Ting Cui Ling Xu Feng Ding Ahmed Alsaedi Tasawar Hayat 《International Journal of Adaptive Control and Signal Processing》2020,34(11):1658-1676
Parameter estimation plays an important role in the field of system control. This article is concerned with the parameter estimation methods for multivariable systems in the state-space form. For the sake of solving the identification complexity caused by a large number of parameters in multivariable systems, we decompose the original multivariable system into some subsystems containing fewer parameters and study identification algorithms to estimate the parameters of each subsystem. By taking the maximum likelihood criterion function as the fitness function of the differential evolution algorithm, we present a maximum likelihood-based differential evolution (ML-DE) algorithm for parameter estimation. To improve the parameter estimation accuracy, we introduce the adaptive mutation factor and the adaptive crossover factor into the ML-DE algorithm and propose a maximum likelihood-based adaptive differential evolution algorithm. The simulation study indicates the efficiency of the proposed algorithms. 相似文献
9.
Huizhu Cai Bingbing Chen Xiao Zhang Yuchen Deng Dequan Xiao Ding Ma Chuan Shi 《Nano Research》2021,14(1):122-130
Over recent years,catalytic materials of Fe-N-C species have been recognized being active for oxygen reduction reaction(ORR).However,the identification of active site remains challenging as it generally involves a pyrolysis process and mixed components being obtained.Herein Fe3C/C and Fe2N/C samples were synthesized by temperature programmed reduction of Fe precursors in 15%CH4/H2and pure NH3,respectively.By acid leaching of Fe2N/C sample,only single sites of FeN4species were presented,providing an ideal model for identification of catalytic functions of the single sites of FeN4in ORR.A correlation was conducted between the concentration of FeⅡN4in low spin state by Mossbauer spectra and the kinetic current density at 0.8 V in alkaline media,and such a structure-performance correlation assures the catalytic roles of low spin FeⅡN4 species as highly active sites for the ORR. 相似文献