Vitrectomy is a common clinical treatment for fundus disease. Due to the non-renewable nature of the vitreous, artificial vitreous are usually required to replace natural vitreous to perform functions post operation. Silicone oil and gas, as the most commonly used vitreous substitutes, have obvious drawbacks, which may lead to postoperative posture maintenance, visual impairment, cataract formation and secondary surgery. In this study, an in situ cross-linked bionic hydrogel (OAHA-CDHA/Col) based on hyaluronic acid (HA) and collagen (Col) with available gelling time for clinical operation, excellent self-healing and fatigue resistance, as well as suitable mechanical and optical properties is constructed. The compatibility and degradability of OAHA-CDHA/Col hydrogel are verified, as well as the feasibility as vitreous substitute in rabbit vitrectomy model. Notably, the hydrogel demonstrates improved intraocular tolerance compared with silicone oil, with no cataracts, endophthalmitis, fundus lesions and other complications observed. These findings position the OAHA-CDHA/Col hydrogel as a promising candidate for an ideal vitreous substitute.
Materials of engineering and construction. Mechanics of materials
This study examines the crystallization kinetics of Ni _50−x Mn _39 Sn _11 Fe _x (x = 0, 0.5, 2, 4 at.%) amorphous thin films prepared by DC magnetron sputtering. SEM and XRD confirm their amorphous structure. Non-isothermal DSC results show that the crystallization peak temperature increases from 542.7 K to 568.0 K as Fe content rises, while the apparent activation energy increases from 96.69 to 152.93 kJ mol ^−1 , indicating enhanced resistance to crystallization. Isothermal analysis yields Avrami exponents of 1.15–1.41 (average ≈1.2), corresponding to diffusion-controlled one-dimensional growth. Local activation-energy evaluation further reveals composition-dependent differences in nucleation and growth during various stages. These quantitative kinetic parameters clarify the role of Fe in altering crystallization behavior and support the optimization of annealing conditions for Ni-Mn-Sn-based functional thin films.
Materials of engineering and construction. Mechanics of materials, Chemical technology
Takuya Sasatani, Alanson P. Sample, Yoshihiro Kawahara
Magnetoquasistatic wireless power transfer can be used to charge and power electronic devices such as smartphones and small home appliances. However, existing coil-based transmitters, which are composed of wire conductors, have a limited range. Here we show that multimode quasistatic cavity resonance can provide room-scale wireless power transfer. The approach uses multidirectional, widely distributed currents on conductive surfaces that are placed around the target volume. It generates multiple, mutually unique, three-dimensional magnetic field patterns, where each pattern is attributed to different eigenmodes of a single room-scale resonator. Using these modes together, a power delivery efficiency exceeding 37.1% can be achieved throughout a 3 m * 3 m * 2 m test room. With this approach, power exceeding 50 W could potentially be delivered to mobile receivers in accordance with safety guidelines.
Muhammad Mohsin, Stefano Rovetta, Francesco Masulli
et al.
Critical Raw Materials (CRMs) such as copper, manganese, gallium, and various rare earths have great importance for the electronic industry. To increase the concentration of individual CRMs and thus make their extraction from Waste Printed Circuit Boards (WPCBs) convenient, we have proposed a practical approach that involves selective disassembling of the different types of electronic components from WPCBs using mechatronic systems guided by artificial vision techniques. In this paper we evaluate the real-time accuracy of electronic component detection and localization of the Real-Time DEtection TRansformer model architecture. Transformers have recently become very popular for the extraordinary results obtained in natural language processing and machine translation. Also in this case, the transformer model achieves very good performances, often superior to those of the latest state of the art object detection and localization models YOLOv8 and YOLOv9.
Hsin-Cheng Lin, Wei-Teng Hsu, Tsai-Yu Chung
et al.
RF array performance of stacked nanosheets, stacked nanowires, FinFETs, and TreeFETs are optimized using double-sided gate contact, contact over active-gate, and proposed hybrid layouts. For the double-sided gate contact, gate resistance increases with the increasing active region width to decrease the maximum oscillation frequency. The gate vias on the active region of contact over active-gate can reduce gate resistance by providing vertical paths for small-signal gate current. Combining the advantages of double-sided gate contact and contact over active-gate, the hybrid can further reduce the gate resistance to improve the maximum oscillation frequency. FinFETs/TreeFETs with the vertical sections of the channel (fin/interbridge) stop the lateral small-signal gate current path to increase gate resistance and thus decrease the maximum oscillation frequency as compared to nanosheets and nanowires. Nanowires adopting the hybrid layout and gate length of 18nm can achieve the highest maximum oscillation frequency of 590GHz due to the lowest gate resistance, the highest electron concentration, and the best gate control.
Mohammad Mustafizur Rahman, Rashed Abdullah, Arif Ahammad
et al.
This paper accentuates the study of LLC resonant converter by a comparative analysis of the properties of LLC resonant and pulse width modulation direct current-direct current converters. Lately, LLC resonant converters have become more appealing and desirable in many applications than other pulse width modulation converters (e.g., Buck, Boost, Cuk) for their soft-switching techniques like zero voltage switching, zero current switching as well as low electromagnetic interference. This paper presents an analysis of efficiency variation, output voltage’s ripple, and various transient performances like percentage overshoot, and the settling time with the variation of load current in a comparative way between LLC resonant converter’s buck, boost operation, and conventional pulse width modulation converter’s buck, boost operation. Feedback proportional-integral-derivative duty cycle controller is used in all converter topologies for some specific analysis. A fixed input voltage of 100 V is selected for simulation and an output voltage of 24 V for buck operation and 120 V for boost operation are chosen. For simulation purposes, MATLAB/SIMULINK software is used.
Dispersion in optical coherence tomography (OCT) poses a challenge that is exacerbated by the increased spectral bandwidth, which leads to image blur and feature loss. In this paper, we present a straightforward and cost-effective approach for dispersion compensation in OCT. To achieve this, we employed a pixel-to-pixel (Pix2Pix) generative adversarial network (GAN) architecture customized for image-to-image translation. Two data groups with varying amounts of training image data and epochs were used. The Pix2Pix GAN was trained to generate clear OCT images from the corresponding dispersion-affected OCT images in paired datasets. According to the experimental results, the Pix2Pix GAN technique demonstrated a substantial improvement over the basic GAN. Specifically, it increases the peak signal-to-noise ratio (PSNR) by 159%, structural similarity index (SSIM) by 370%, and Fréchet inception distance (FID) by 274%. These outcomes indicate that the proposed model can generate images with resilience and effectiveness, particularly when dealing with dispersion-affected OCT data.
While current research predominantly focuses on image-based colorization, the domain of video-based colorization remains relatively unexplored. Many existing video colorization techniques operate frame-by-frame, often overlooking the critical aspect of temporal coherence between successive frames. This approach can result in inconsistencies across frames, leading to undesirable effects like flickering or abrupt color transitions between frames. To address these challenges, we combine the generative capabilities of a fine-tuned latent diffusion model with an autoregressive conditioning mechanism to ensure temporal consistency in automatic speaker video colorization. We demonstrate strong improvements on established quality metrics compared to existing methods, namely, PSNR, SSIM, FID, FVD, NIQE and BRISQUE. Specifically, we achieve an 18% improvement in performance when FVD is employed as the evaluation metric. Furthermore, we performed a subjective study, where users preferred LatentColorization to the existing state-of-the-art DeOldify 80% of the time. Our dataset combines conventional datasets and videos from television/movies. A short demonstration of our results can be seen in some example videos available at <uri>https://youtu.be/vDbzsZdFuxM</uri>.
Microwave wireless communication technologies have greatly evolved over the years and are nowadays experiencing tremendous growth driven by an explosive broadening of their application [...]
The design of a solid-state quantum processor is nowadays a hot research topic in microelectronics. Like the logic gates in a classical processor, quantum gates serve as the fundamental building blocks for quantum processors. The main goal of the present paper is to deduce the matrix of the main one- and two-qubit quantum gates from the Schrödinger equation. The mathematical formalism is kept as comfortable as possible for electronics engineers. This paper does not cover topics such as dissipations, state density, coherence, and state purity. In a similar manner, this paper also deals with the quantum nature of a quantum processor by leveraging the concept of a finite-state machine, which is a background notion for any electronics engineer.
Topology captures the essence of what remains unchanged under a transformation. In this study, a topological invariant called super conformality was found to preserve a critical angle between the constitutive plane and its second order differential plane for a two-terminal electric element as building blocks of modern electronics. This super conformality leads to local activity of a higher-order electric element so that the periodic table of the electric elements can be dramatically reduced to have only 6 passive ones, in contrast to the unbounded table predicted 40 years ago. Our claim that all the higher-order electric elements must be active was experimentally verified by the fact that a 2nd-order sodium memristor in the famous Hodgkin-Huxley circuit is locally active with an internal battery.
A number of novel two-dimensional materials and nanostructures demonstrate complex single-electron energy dispersion, which is called the mexican-hat dispersion. In this paper, we analyze interaction of a pair of electrons with such an energy dispersion. We show that relative motion of the electron pair is of a very peculiar character. For example, the real space trajectories corresponding to electron-electron scattering can have three reversal points, reversal points at non-zero radial momentum and other unusual features. Despite the repulsive Coulomb interaction, two electrons can be coupled forming a composite quasi-particle - the bi-electron. The bi-electron corresponds to excited states of the two-electron system. Because the bi-electron coupled states exist in continuum of extended (free) states of the electron pair, these states are quasi-resonant and have finite times of life. We found that rotating bi-electron is a long-living composite quasi-particle. The rotating bi-electrons can be in motion. For slowly moving bi-electrons, we determined the kinetic energy and the effective mass. Due to strongly nonparabolic energy dispersion, the translational motion of the bi-electron is coupled to its internal motion. This results in effective masses dependent on quantum states of the bi-electron. In the paper, properties of the bi-electron are illustrated for the example of bigraphene in a transverse electric field.
Neophytos Neophytou, Pankaj Priyadarshi, Zhen Li
et al.
Over the last two decades a plethora of new thermoelectric materials, their alloys, and their nanostructures were synthesized. The ZT figure of merit, which quantifies the thermoelectric efficiency of these materials increased from values of unity to values consistently beyond two across material families. At the same time, the ability to identify and optimize such materials, has stressed the need for advanced numerical tools for computing electronic transport in materials with arbitrary bandstructure complexity, multiple scattering mechanisms, and a large degree of nanostructuring. Many computational methods have been developed, the majority of which utilize the Boltzmann transport equation (BTE) formalism, spanning from fully ab initio to empirical treatment, with varying degree of computational expense and accuracy. In this paper we describe a suitable computational process that we have recently developed specifically for thermoelectric materials. The method consists of three independent software packages that we have developed and: 1) begins from ab initio calculation of the electron-phonon scattering rates, 2) to then be used within a Boltzmann transport simulator, and 3) calculated quantities from BTE are then passed on to a Monte Carlo simulator to examine electronic transport in highly nanostructured material configurations. The method we describe is computationally significantly advantageous compared to current fully ab initio and existing Monte Carlo methods, but with a similar degree of accuracy, thus making it truly enabling in understanding and assessing thermoelectric transport in complex band, nanostructured materials.
In this study, the mechanical models of a multilayer combined extrusion cylinder and a steel-wire-winding extrusion cylinder were established and compared using a finite element simulation and existing experimental cases. This work provides theoretical support for the selection of an ultrahigh-pressure extrusion cylinder. Comparative analysis of an ultrahigh-pressure extrusion structure was carried out. The mathematical optimization model is established based on the mechanical model, and the ultimate bearing capacities of the schemes are compared. Additionally, the winding mode and the number of core layers of the extrusion cylinder are compared and analyzed, which provides a theoretical basis for the parameter design of the steel-wire-winding ultrahigh-pressure extrusion cylinder. This work holds good theoretical significance and practical value for the promotion and application of ultrahigh-pressure hydrostatic extrusion technology.
Materials of engineering and construction. Mechanics of materials, Production of electric energy or power. Powerplants. Central stations
Subhashree Choudhury, George Tom Varghese, Satyajit Mohanty
et al.
A comparative study of energy management strategies and PQ improvement schemes for a Fuel Cell, Battery, and SuperCapacitor integrated Microgrid system has been projected utilizing the MATLAB/Simulink architecture in this research article. For effective energy management and PQ enhancement, a Modified Water Wave Optimization algorithm based on adaptive population size and adaptive wavelength coefficient has been proposed. The MWWO method robustly and dynamically tunes the parameters of the Proportional Integral controller for effective operation. The efficiency of the proposed technique has been compared with the traditional methods regarding hydrogen consumption, load power deliberation, power quality and overall system efficiency. The results obtained and the numerical analysis confers the superiority of the suggested technique over other methods for enhanced dynamic voltage response, low fuel consumption, reduced harmonics and better efficacy thereby proving its real-time employment.
Tree height is a crucial structural parameter in forest inventory as it provides a basis for evaluating stock volume and growth status. In recent years, close-range photogrammetry based on smartphone has attracted attention from researchers due to its low cost and non-destructive characteristics. However, such methods have specific requirements for camera angle and distance during shooting, and pre-shooting operations such as camera calibration and placement of calibration boards are necessary, which could be inconvenient to operate in complex natural environments. We propose a tree height measurement method based on three-dimensional (3D) reconstruction. Firstly, an absolute depth map was obtained by combining ARCore and MidasNet. Secondly, Attention-UNet was improved by adding depth maps as network input to obtain tree mask. Thirdly, the color image and depth map were fused to obtain the 3D point cloud of the scene. Then, the tree point cloud was extracted using the tree mask. Finally, the tree height was measured by extracting the axis-aligned bounding box of the tree point cloud. We built the method into an Android app, demonstrating its efficiency and automation. Our approach achieves an average relative error of 3.20% within a shooting distance range of 2–17 m, meeting the accuracy requirements of forest survey.
Abstract Functional encryption (FE) is a novel paradigm for encryption scheme which allows tremendous flexibility in accessing encrypted information. In FE, a user can learn specific function of encrypted messages by restricted functional key and reveal nothing else about the messages. Inner product encryption (IPE) is a special type of functional encryption where the decryption algorithm, given a ciphertext related to a vector x and a secret key related to a vector y, computes the inner product x·y. In this paper, we construct an efficient private-key functional encryption (FE) for inner product with simulation-based security, which is much stronger than indistinguishability-based security, under the External Decisional Linear assumption in the standard model. Compared with the existing schemes, our construction is faster in encryption and decryption, and the master secret key, secret keys and ciphertexts are shorter.
Предмет: використання математичного апарату нейронних мереж для наукового обгрунтування протиепідемічних заходів з метою зниження захворюваності при прийнятті ефективних управлінських рішень. Ціль: застосувати кластерний аналіз, на основі нейронної мережі, для вирішення задачі виділення зон розповсюдження захворюваності. Задачі: проаналізувати методи аналізу даних для вирішення задачі кластеризації; розробити нейромережевий метод кластеризації територій України за характером епідемічного процесу COVID-19; на основі розробленого методу реалізувати програмний додаток аналізу даних для виділення зон розповсюдження захворюваності на прикладі коронавірусу COVID-19. Методи: моделі та методи аналізу даних, моделі та методи теорії систем (на базі інформаційного підходу), методи машинного навчання, зокрема метод Adaptive Boosting (на основі методу градієнтного спуску), методи навчання нейронних мереж. Результати: були використані розподілені по областям України дані Центру громадського здоров’я МОЗ України про захворюваність на COVID-19, кількість лабораторно обстежених осіб, кількість проведених лабораторних досліджень методами ПЦР та ІФА, кількість проведених лабораторних досліджень IgA, IgM, IgG; в моделі використані дані з березня 2020 по грудень 2020, при моделюванні не враховані дані з тимчасово окупованих територій України; для кластерного аналізу побудована нейронна мережа з 60 вхідними нейронами, 100 прихованими нейронами з активаційною функцією Фермі та 4 вихідними нейронами; для програмної реалізації моделі використана мова програмування Python. Висновки: проведено аналіз методів побудови нейронних мереж; аналіз методів навчання нейронних мереж, у тому числі методу градієнтного спуску; всі теоретичні вiдомостi, описанi в цiй роботi, були використанi для реалiзації програмного продукту обробки даних тестування на COVID-19 в Україні; було проведено розбиття областей України на зони зараження вірусом COVID-19 та представлено карту цього розбиття.
In recent years, power converters have played an important role in power electronics technology for different applications, such as renewable energy systems, electric vehicles, pulsed power generation, and biomedical [...]