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Dielectric Spectroscopy Studies and Modelling of Piezoelectric Properties of Multiferroic Ceramics
No full textCompounds and solid solutions of bismuth ferrite (BiFeO3)-barium titanate (BaTiO3) system are of great scientific and engineering interest as multiferroic and potential high-temperature lead-free piezoelectric materials. In the present paper, the results of research on the synthesis and characterisation of 0.67Bi(1).02FeO3-0.33BaTiO(3) (67BFBT) ceramics in terms of crystal structure and dielectric and piezoelectric properties are reported. It was found that the produced 67BFBT ceramics were characterised by a tetragonal crystal structure described by the P4mm space group, an average crystallite size <D> & AP; 80 nm, and an average strain <& epsilon;> = 0.01%. Broad-band dielectric spectroscopy (BBDS) was employed to characterise the dielectric response of polycrystalline ceramics. The frequency range from & nu; = 10(-1) Hz to & nu; = 10(5) Hz was used to characterise the influence of the electric field strength on dielectric response of the ceramic sample at room temperature. The dielectric spectra were checked for consistency with the Kramers-Kronig test, and the high quality of the measurements were confirmed. The electric equivalent circuit method was used to fit the dielectric spectra within the frequency range that corresponded to the occurrence of the resonant spectra of the radial mode for thin disk sample, i.e., from & nu; = 10(5) Hz to & nu; = 10(7) Hz and the temperature range from T = -20 & DEG;C to T = 50 & DEG;C. The electric equivalent circuit [RsCPE1([L1R1C1]C-0)] was used, and good fitting quality was reached. The relevant calculations were performed, and it was found that the piezoelectric charge coefficient exhibited a value of d(31) = 35 pC/N and the planar coupling factor was k(p) = 31% at room temperature. Analysis of impedance spectra performed in terms of circumferential magnetic field made it possible to establish an influence of magnetic field on piezoelectric parameters of 67BFBT multiferroic ceramics. Additionally, the "magnetic" tunability of the modulus of the complex dielectric permittivity makes 67BFBT a sensing material with vast potential
Full-Hexacyanometallate Aqueous Redox Flow Batteries Exceeding 1.5 V in an Aqueous Solution
No full textAqueous redox flow batteries (RFBs) have attracted significant attention as energy storage systems by virtue of their inexpensive nature and long-lasting features. Although all-vanadium RFBs exhibit long lifetimes, the cost of vanadium resources fluctuates considerably, and is generally expensive. Iron-chromium RFBs take advantage of utilizing a low-cost and large abundance of iron and chromite ore; however, the redox chemistry of Cr-II/III generally involves strong Jahn-Teller effects. Herein, this work introduces a new Cr-based negolyte coordinated with strong-field ligands capable of mitigating strong Jahn-Teller effects, thereby facilitating low redox potential, high stability, and rapid kinetics. The balanced full-cell configuration features a stable lifetime of 500 cycles with energy density of 14 Wh L-1. With an excessive posolyte, the full-cell can attain a high energy density of 38.6 Wh L-1 as a single electron redox process. Consequently, the proposed system opens new avenues for the development of high-performance RFBs
Insights of Peculiar Green-Yellow Emission Occurrence in Ce3+-Doped Barium Yttrium Orthogermanate Phosphors
No full textOxygen vacancies were observed in thephosphors throughinvestigating bond-length fluxations using synchrotron X-ray diffractionrefinement, X-ray photoelectron spectroscopy, and Ge K-edge X-rayabsorption near-edge structure spectra. The Ba8.8Ce0.1Na0.1Y2Ge6O24 orthogermanate phosphor, preparedbyLiCl flux assistance under a reducing atmosphere, exhibited a mysteriousgreen-yellow emission at 298 K. A blue-emitting orthogermanate phosphorwas expected to be achieved through the lower d-band of Ce3+ ions in the host structure owing to their optical structure geometry.Oxygen vacancies were observed in the phosphors through investigatingbond-length fluxations, the oxygen 1s profile, and the Ge2+/Ge4+ oxidation state, using synchrotron X-ray diffractionrefinement, X-ray photoelectron spectroscopy, and Ge K-edge X-rayabsorption near-edge structure spectra, respectively. The Ba-M-4,M-5 edge shift, bonding limitation, and distortion index discoveryreveal the oxygen-coordinating environment variation around the Ba2+(Ce3+) ions in the phosphors. The green-yellowemission results from the active 6-coordinated antiprism oxygen geometryaround the Ce3+ ions in the phosphors
Enabling Delay-Guaranteed Congestion Control With One-Bit Feedback in Cellular Networks
No full textUnexpected large packet delays are often observed in cellular networks due to huge network queuing caused by excessive traffic coming into the network. To deal with the large queue problem, many congestion control algorithms try to find out how much traffic the network can accommodate, either by measuring network performance or by directly providing explicit information. However, due to the nature of the control in which queue growth should be observed or the necessity to modify the overall network architecture, existing algorithms are experiencing difficulties in keeping queues within a strict bound. In this paper, we propose a novel congestion control algorithm based on simple feedback, ECLAT which can provide bounded queuing delay using only one-bit signaling already available in traditional network architecture. To do so, a base station or a router running ECLAT 1) calculates how many packets each flow should transmit and 2) analyzes when congestion feedback needs to be forwarded to adjust the flow's packet transmission to the desired rate. Our extensive experiments in our testbed demonstrate that ECLAT achieves strict queuing delay bounds, even in the dynamic cellular network environment
Designing Interfaces for Text-To-Image Prompt Engineering Using Stable Diffusion Models: A Human-AI Interaction Approach
No full textThe use of generative artificial intelligence (AI) is more vital ever than before to create new content, especially images. Recent breakthroughs in text-to-image diffusion models showed the potential to drastically change the way we approach image content creation. However, artists still face challenges when attempting to create images that reflect their specific themes and formats, as the current generative systems, such as Stable Diffusion models, require the right prompts to achieve the desired artistic outputs. In this paper, we propose future design considerations to develop more intuitive and effective interfaces that can be used for text-to-image prompt engineering from a human-AI interaction perspective using a data-driven approach. We collected 78,911 posts from the internet community and analyzed them through thematic analysis. Our proposed directions for interface design can help improve the user experience as well as usability, ultimately leading to a more effective, desired image generation process for creators
Enhancing Biocompatibility of Photosensitizers and Overcoming Hypoxia for Photodynamic Therapy
No full textAn electron acceptor with an intrinsic quinoidal core for bulk-heterojunction organic solar cells and photodetectors
No full textAn electron acceptor based on a quinoidal dipyrrolopyrazinedione core was synthesized for organic solar cells and photodetectors. A power conversion efficiency of 6.7% and a specific detectivity of 4.1 x 10(13) Jones at 800 nm have been obtained, suggesting the promising prospects of quinoidal molecules for optoelectronic devices
Antibody plug-and-playable nanoparticles as a facile and versatile platform for targeted drug delivery
No full textFor effective drug delivery using nanoparticles, antibody can be beneficially utilized thanks to its high binding affinity to the target site. However, a conventional method to conjugate antibody to nanoparticles involves a multi-step synthetic process, which can damage the antibody's intrinsic target-recognition nature. Herein, a facile approach is reported to construct a versatile targeted delivery platform, to which any desired antibodies are allowed to directly bind, by coating the nanoparticle surface with a functional fusion protein consisting of glutathione-S-transferase (GST) and the antibody-binding domain (ABD) called Z domain. The antibody-plugged nanoparticle exhibits high structural stability in biological environments and cell-specific targeting behaviors, significantly enhancing drug delivery efficiency both in vitro and in vivo for diverse therapeutic applications
Effects of wavy structure, ambient conditions and solar intensities on flow and temperature distributions in a mini solar flat plate collector using computational fluid dynamics
No full textMini solar flat plate collectors have gained traction due to their cost-effectiveness, high efficiency in converting solar radiation to heat energy, and versatility in residential and commercial applications, offering long lifespans with minimal maintenance. Optimizing the thermal performance of solar flat plate collectors using numerical simulations helps enhance their efficiency, making them even more appealing for small-scale heating and hot water applications. This study investigates the flow behavior and temperature distribution of air within a small-sized solar collector (286 x 800 x 70 mm) and optimizes its design for achieving the highest outlet air temperature. The optimization process included varying geometric parameters, such as the wavy structure hole diameter, and considering a range of operating conditions, including ambient conditions and solar intensities. This analysis aimed to understand the flow behavior and temperature distributions within the solar collector. The numerical studies provided valuable insights into the thermal and flow characteristics of the collector. The velocity distribution of the fluid within the collector aided in understanding the flow behavior, optimizing the flow path to minimize pressure drop, and maximizing heat transfer. Additionally, calculations were performed to determine total useful heat, outlet temperatures, and efficiencies. The study also discusses the optimal design and operating conditions for the collector