Applied Research最新文献

The main purpose of many current studies regarding energy efficiency is the improvement of the thermal resistance of buildings. To fulfill this goal, the development of advanced insulating materials, to be incorporated in the building envelopes, is imperative. Aerogels are ultralight porous materials typically produced via the sol-gel process followed by supercritical drying of the wet gel. They exhibit very high porosities and a mesoporous-macroporous structure which endows aerogels with extremely low thermal conductivity. This makes them ideal candidates for ambient thermal insulation applications. However, the cost for aerogel insulation is considerably higher than the one of standard insulation products. In the present work, highly porous aerogel-like materials based on silica and commercial novolac resin were developed and added to common mortars. The prepared materials were dried under ambient pressure to minimize the manufacturing cost. The bulk density of silica quasi-aerogels was 0.03 g/cm³–0.09 g/cm³ and that of the novolac resin samples 0.09 g/cm³–0.21 g/cm³. The aerogels were incorporated in mortars and cured for 28 days before measurement of thermal conductivity. The values of the thermal conductivity coefficient of the measured samples were 0.047 W/m K–0.058 W/m K for the silica reinforced mortars and 0.036 W/m K–0.044 W/m K for the novolac reinforced ones.

Climate change is one of the significant challenges of the 21st century. To achieve climate goals a change in plastic waste management needs to be implemented. This research examines the potential of thermo-mechanical recycling of plastic waste, focusing on agricultural binding twines made from polypropylene. Old binding twines from agriculture were collected and recycled with a twin screw extruder. The ageing behaviour of the recyclate in terms of multiple recycling is examined in detail with tensile tests and melt volume rate measurements. The findings indicate a general degradation in mechanical properties and a decrease in viscosity due to molecular chain scission. Despite these degradations, the material remains processable, indicating the potential for continued recycling loops.

Plasmonic sensors based on metal-insulator-metal (MIM) waveguides are renowned for their miniaturization and high sensitivity in various sensing applications. A broad spectrum of researchers is numerically investigating the characteristics of MIM waveguide-based plasmonic sensors with diverse cavity shapes. However, practical demonstrations of these sensors have not yet been realized, primarily due to the overlooked aspect of the light coupling mechanism into these waveguides. In this context, two distinct methods for coupling light into and out of plasmonic chips based on MIM waveguides are presented.

Silk fiber, often acclaimed as the pinnacle of textile materials, finds contemporary applications in the textile industry, health, and cosmetics. Gallic acid (GA) is a well-established natural antioxidant. In the present study, a novel hybrid material SFd@GA was conceptualized and produced via surface grafting of GA onto degummed silk-fibers (SFd). Successful covalent-grafting of gallic acid onto the silk fabric surface was confirmed through Fourier-transform infrared, Raman, thermogravimetric analysis (TG-DTA), and scanning electron microscopy (SEM). electron paramagnetic resonance spectroscopy demonstrates that gallic moieties grafted on SFd@GA retain their radical/redox activity. The antioxidant capacity of the hybrid material SFd@GA was validated by quantitative analysis of antioxidant hydrogen-atom-transfer (HAT) to DPPH radicals. Our data reveal a 550% increase in antioxidant-HAT activity of SFd@GA versus natural intact silk fiber, and a 1400% increase in antioxidant-HAT activity compared to the degummed silk fiber. The paramount discovery of the present work lies in the capacity for repeated utilization of the hybrid material SFd@GA, without any discernible compromise in its antioxidant-HAT activity. Specifically, we show that SFd@GA can be employed for at least 15 consecutive cycles, retaining >98% of its HAT efficiency, for up to many days of storage under ambient conditions. We discuss this expositional performance via the controllable Hat-activity process that we propose.

In this work, we introduce a novel image zooming methodology that transitions from a nonadaptive Sin-based approach to an adaptive Sinc-based zooming technique. The two techniques base their theoretical foundation on the Whittaker–Shannon interpolation formula and the Nyquist theorem. The evolution into adaptive Sinc-based zoom is accomplished through the use of two novel concepts: (1) the pixel-local scaled k-space and (2) the k-space filtering sigmoidal function. The pixel-local scaled k-space is the standardized and scaled k-space magnitude of the image to zoom. The k-space filtering sigmoidal function scales the pixel-local scaled k-space values into the numerical interval [0, 1]. Using these two novel concepts, the Whittaker–Shannon interpolation formula is elaborated and used to zoom images. Zooming is determined by the shape of the Sinc functions in the Whittaker–Shannon interpolation formula, which, in turn, depends on the combined effect of the pixel-local scaled k-space, the sampling rate, and the k-space filtering sigmoidal function. The primary outcome of this research demonstrates that the Whittaker–Shannon interpolation formula can achieve successful zooms for values of the sampling rate significantly greater than the bandwidth. Conversely, when the sampling rate is much greater than the bandwidth, the nonadaptive technique fails to perform the zoom correctly. The conclusion is that the k-space filtering sigmoidal function is identified as the crucial parameter in the adaptive Sinc-based zoom technique. The implications of this research extend to Sinc-based image zooming applications.

The design and development of photoinitiating systems applicable to visible light delivered from light-emitting diodes (LEDs) have attracted increasing attention owing to the wide application of photopolymerization. In this study, four aryl glycine derivatives are designed and synthesized, and their applicability as visible light-sensitive photoinitiators is thoroughly investigated. Specifically, the photoinitiation mechanism of these aryl glycine derivatives, when combined with iodonium salt, is investigated using steady-state photolysis, fluorescence, and electron paramagnetic resonance spin trapping techniques. It is revealed that radicals can be generated from aryl glycine derivatives/iodonium salt combinations upon exposure to blue LEDs (410 and 445 nm) to induce free radical photopolymerization (FRP) of (meth)acrylates. Additionally, besides FRP, a photobase generator based on one of the investigated aryl glycine derivatives is synthesized and demonstrates the capability to initiate epoxy-thiol polymerization under light irradiation. The remarkable photolatent characteristics demonstrate the significant potential in broadening the application of aryl glycine derivatives in controlled photopolymerization processes.

Optoelectronic devices performance is governed by the band alignment nature in heterojunctions. Interfacial Layers (ILs) play an immense role in charge carrier-selectivity and their transport behavior. Considering the investigations on a wide array of solid-state surfaces and heterojunctions performed both experimentally and theoretically, we found that the electron localizability, which is quantifiable through the bandgap energy and band width, affects the surface properties of crystals and hence the electronic properties of the interfaces. In combination with other observations, a strategy for contact design is developed for enhancing charge carrier transport across the boundaries and the interfaces, one can optimize stack structures with IL by maximizing their respective transport mechanism, similar to what has been done with silicon solar cells by doping. In this case, charge carrier transport across the interface can be maximized by making the depletion region width smaller without altering the heterojunction barrier's height.

In recent years, some homomorphic encryption algorithms have been proposed to provide additive homomorphic encryption and multiplicative homomorphic encryption. However, similarity measures are required for searches and queries under homomorphic encrypted ciphertexts. Therefore, this study considers cosine similarity, angular similarity, Tanimoto similarity, and soft cosine similarity and combines homomorphic encryption algorithms for similarity calculation to propose homomorphic encryption-based cosine similarity (HE-CS), homomorphic encryption-based angular similarity (HE-AS), homomorphic encryption-based Tanimoto similarity (HE-TS), and homomorphic encryption-based soft cosine similarity (HE-SCS). This study proposes mathematical models to prove the proposed homomorphic encryption-based similarity calculation methods and gives practical cases to explain the feasibility of the proposed HE-CS, HE-AS, HE-TS, and HE-SCS. Furthermore, this study proposes normalized entropy and normalized Gini impurity as evaluation factors to measure the randomness and confusion of ciphertext. In experiments, the values of normalized entropy and normalized Gini impurity are higher than 0.999, which indicates significant differences between plaintexts and ciphertexts. Moreover, the encryption time and decryption time of the proposed homomorphic encryption-based similarity calculation methods have been evaluated under different security strengths.

Fully screen-printed silver and copper temperature sensors were studied up to 100°C. The influence of the processing conditions and the composition of three silver and one copper commercial inks is analyzed in this study. The curing temperature is extremely relevant to stabilize the initial resistance of silver sensors, especially for those printed with the lowest solid content ink. All printed sensors showed good linear behavior in the range of 25–100°C (R² > 0.999) except for those fabricated with the lowest solid content silver ink, which also displayed the highest hysteresis and drift. The temperature coefficient of resistance (TCR) obtained for the copper sensors was 3.367 × 10⁻³ K⁻¹ and for the three silver sensors, it ranged between 2.723 × 10⁻³ to 2.963 × 10⁻³ K⁻¹. This TCR is higher than values reported for inkjet-printed resistive temperature detectors. Overall, this work demonstrates that low-cost, linear, screen-printed temperature sensors can be successfully fabricated on flexible substrates.

Solar-driven overall water splitting using particulate photocatalysts represents a sustainable route to generate H₂. In this minireview, we outline recent progress in hybridization strategies in constructing high- performance cocatalyst/photocatalyst systems. We discussed the fundamental principles of photocatalytic water splitting and the pivotal role of cocatalysts. We placed special emphasis on understanding the structure-activity relationship of cocatalysts for effective photocatalytic H₂ production from pure H₂O. We expect this review to offer insights and stimulate further research interest in the development of high-performance cocatalysts for photocatalytic water splitting.