Search Results (2,539)

The diketopyrrolopyrrole (DPP) core is widely recognized for its applications in organic electronics and photonics due to its exceptional electronic and optical properties. Recently, DPP-based materials have shown remarkable π–π stacking interactions and tunable self-assembly, making them promising candidates for gel formation. However, the development of DPP-based gels remains in its infancy, primarily hindered by challenges such as limited gelation efficiency, poor mechanical robustness, and sensitivity to environmental conditions. Overcoming these issues is crucial for unlocking their full potential in functional soft materials. This review compiles and analyzes existing studies on DPP-containing gel systems, highlighting their structural versatility, self-assembly mechanisms, and advantages over conventional gelators. By examining these works, we identify key strategies for DPP gel formation, evaluate their physicochemical performance, and discuss innovative approaches to address current limitations. Finally, we propose future research directions to advance the field and establish DPP-based gels as a robust platform for next-generation soft materials. Full article

This study provides a theoretical analysis of how the electrical characteristics of the medium affect the propagation of electric fields. Every medium has specific electrical conductivity and permittivity values and can be evaluated as a good conductor or a good dielectric depending on the ratio of conduction current to displacement current. The strength of the electric field decreases significantly with the propagation distance due to the influence of high conductivity. In conclusion, even media with a high permittivity may be unsuitable for improving the performance of the capacitive power transfer (CPT) system depending on its conductivity. The analysis was verified for four types of water with different conductivities. In addition, we designed a stacked CPT coupler structure and analyzed its underwater transfer characteristics. In conclusion, unlike the parallel CPT coupler, the stacked CPT coupler is relatively disadvantageous for underwater use. Full article

This study proposes a method for time-efficient order picking based on a structural stability assessment (SSA) when target boxes inside box-stacking storage (BSS) on multi-layer racks are removed. This method performs optimal order picking by generating a path to directly pick the target box without first picking the upper boxes in the BBS, if it is possible to pick the target box directly. The SSA algorithm generates images of the complement structure by removing the target box within BBS and uses them as input data for the CNN model to evaluate the stability of the structure. To create the CNN model, we generated a dataset using CoppeliaSim simulation, considering the size and shape of the overall structure of the BBS, the size and number of each box, and the number of target boxes. The accuracy of the generated CNN model was 95.1% on test data, while it achieved 97% accuracy when using real-world data. This validation process confirmed that the algorithm can be effectively applied to real BBS logistics environments to perform optimal order picking. Full article

Two new Co(II) coordination compounds viz. [Co(H₂O)(bz)₂(μ-3-Ampy)₂]_n (1) and [Co(4-Mebz)₂(2-Ampy)₂] (2) (wherebz = benzoate, 4-Mebz = 4-Methylbenzoate and Ampy = Aminopyridine) were synthesized and characterized via elemental (CHN), electronic spectroscopy, FT-IR spectroscopy, and thermogravimetric analysis (TGA). The molecular structures were determined by single-crystal X-ray diffraction analysis, inferring that compound 1 crystallizes as a 3-Ampy bridged Co(II) coordination polymer, whereas compound 2 crystallizes as a mononuclear Co(II) compound. Compound 1 unfolds the presence of N–H⋯O, C–H⋯O, O–H⋯O, C–H⋯N and aromatic π⋯π interactions, while for compound 2, N–H⋯O, C–H⋯O, C–H⋯C and C–H⋯π interactions are observed. Both the compounds showcase scarcely reported chelate ring interactions involving the benzoate moiety (chelate ring⋯π in 1 and N–H⋯chelate ring in 2). We also conducted theoretical evaluations comprising of combined QTAIM/NCI plot analysis, DFT energy calculation and MEP surface analysis to analyze the supramolecular interactions present in the crystal structures. As per QTAIM parameters, the predominance of π-stacking interactions over hydrogen bonds in stabilizing the assembly in compound 1 is affirmed. Likewise, in compound 2, both hydrogen bonding (HBs) and C–H⋯π interactions are deemed pivotal in stabilizing the dimeric assemblies. The in vitro antiproliferative activities of compounds 1 and 2 were performed against Dalton’s lymphoma (DL) cancer cell lines through cytotoxicity and apoptosis assays, showcasing higher cytotoxicity of compound 1 (IC₅₀ = 28 μM) over compound 2 (IC₅₀ = 34 μM). Additionally, a molecular docking study investigated the structure–activity relationship of these compounds and allowed an understanding of the molecular behaviour after treatment. Full article

Materials utilized in extreme environments, such as those necessitating protection and impact resistance at cryogenic temperatures, must exhibit high strength, ductility, and structural stability. However, most alloys fail to maintain adequate toughness at cryogenic temperatures, thereby compromising their safety during cryogenic temperature service. This study investigates the quasi-static mechanical properties of a CoCr₀.₄NiSi₀.₃ medium-entropy alloy (MEA) at room temperature, −75 °C, and −150 °C. The deformation behavior and mechanisms responsible for strengthening and toughening at reduced cryogenic temperatures are analyzed, revealing that decreasing cryogenic temperature enhances the strength of the as-cast MEA. Specifically, both the yield strength (YS) and ultimate tensile strength (UTS) of the MEA increase significantly with decreasing temperature during cryogenic tensile testing. Under tensile testing at −150 °C, the YS reaches 617.5 MPa, the UTS is 1055.0 MPa, and the elongation to fracture remains approximately 21.0% at both −150 °C and −75 °C. After cryogenic temperature tensile deformation, the matrix exhibits a dispersed distribution of nanoscaled tetragonal and orthorhombic phases, a coherent hexagonal close-packed phase, L1₂ phase and layered long-period stacking ordered (LPSO) structures, which are rarely observed in the cryogenic deformation of metals and alloys. The metastable phase evolution path of this MEA at cryogenic temperatures is closely associated with the decomposition of perfect dislocations into a/6<112> Shockley partial dislocations and their subsequent evolution at reduced cryogenic temperatures. At −75 °C, the a/6<112> Shockley partial dislocation interacts with the L1₂ phase to form antiphase boundaries (APBs) approximately 3 nm thick. At −150 °C, two phase transition paths from stacking faults (SFs) to nanotwins and LPSO occur, leading to the formation of layered LPSO structures and deformation-induced nanotwins. The dispersion of these coherent nanophases and nanotwins induced by the reduced stacking fault energy under cryogenic temperatures is the key factor contributing to the excellent balance of strength and plasticity in the as-cast MEA, providing an important basis for research on the cryogenic mechanical properties of CoCrNi-based MEAs. Full article

Perylene diimide (PDI), initially synthesized and explored as an organic dye, has since gained significant recognition for its outstanding optical and electronic properties. Early research primarily focused on its vibrant coloration; however, the resolution of solubility challenges has revealed its broader potential. PDIs exhibit exceptional optical characteristics, including strong absorption and high fluorescence quantum yield, along with remarkable electronic properties, such as high electron affinity and superior charge carrier mobility. Furthermore, the robust π-π stacking interactions and liquid crystalline behavior of PDIs facilitate precise their self-assembly into highly ordered structures, positioning them as valuable materials for advanced applications in optoelectronics, photonics, and nanotechnology. This article provides a comprehensive review of the progress made in the design, synthesis, and optoelectronic performance of PDI-based liquid crystals. It explores how various substituents and their placement on the PDI core impact the properties of these liquid crystal molecules and discusses the challenges and opportunities that shape this rapidly evolving class of optical materials. This review is strictly focused on PDIs and does not cover their elongated or laterally extended derivatives, nor does it include monoimide or ester compounds. Full article

Concrete is one of the most commonly used construction materials worldwide, and its compressive strength is the most important mechanical property to be defined at the time of structural design. Establishing a relationship between the amount of each component in the mixture and the properties of the concrete is not a trivial task, since a high degree of nonlinearity is involved. However, the use of machine learning methods as modeling tools has assisted in overcoming this difficulty. The objective of this work is to investigate the efficiency of using stacking as a technique for predicting the compressive strength of concrete mixtures. Four datasets obtained from the literature were used to verify the generalization capacity of the stacking technique; these datasets included a number of samples and numbers and types of attributes. Statistical tests were used to compare the existence of significant similarities between stacking and individual machine learning models. The results obtained from the statistical tests and evaluation metrics show that stacking yields results similar to those of the standalone machine learning models, with better performance. Full article

The synthesis of 7-O-carboxymethyl-4′-fluoroisoflavone 4 and 7-O-carboxymethyl-4′-fluoro-2-trifluormethylisoflavone 7 involved the cyclization of 2,4-dihydroxy-4′-fluorodeoxybenzoin 1, followed by 7-O-alkylation with methyl bromoacetate and subsequent acid-catalyzed hydrolysis. The structures of the novel compounds were validated using a range of techniques, including XRD crystallography (¹H, ¹⁹F, ¹³C)-NMR, and IR. Only interhalogen contacts were detected in 5, while they were completely lacking in 2 and 4, owing to the presence of crystalline ethanol in the crystal structure. The %F…F in 5 was 12.2% based on Hirshfeld calculations. The aromatic π-π stacking interactions were important only in 2 and 4 but not observed in 5. Isoflavones 4, 5, and 7 displayed anticancer activity against MCF-7 cancer cells, with IC₅₀ values of 13.66, 15.43, and 11.73 µM, respectively. Full article

Polycyclic aromatic hydrocarbons (PAHs) are one of the most toxic environmental pollutants, which are very harmful to the human body. It is crucial to find convenient and effective detection methods of PAHs for preventing and controlling environmental pollution. Low-dimensional material-based field effect transistor (FET) sensors exhibit the advantages of a small size, simple structure, fast response, and high sensitivity. In this work, graphene (Gr) has been selected as the channel material for FET sensors for PAH detections. Through π-π electron stacking interactions, PAHs could be spontaneously adsorbed on the surface of the Gr and affect its electronic carrier transport behavior. Based on the relationship between the concentrations and the changes in the Dirac point of the Gr, the sensor achieved an effective response to PAHs in a broad range from 10⁻¹⁰ to 10⁻⁶ mol/L and a limit of detection of 10⁻¹⁰ mol/L was obtained, which was lower than that provided by the World Health Organization (3.46 × 10⁻⁹ mol/L), in drinking water. The results demonstrate a great application of the FET sensors in environmental analysis, and provide an important way for rapid and in situ monitoring of PAHs. Full article

This paper presents the world’s smallest two-phase flux-switching motor (FSM), featuring a four-pole stator and a two-pole rotor with a non-uniform air gap design. The FSM offers several advantages, including a compact size, simple structure, and ease of manufacturing, making it suitable for future micromachine applications. The motor has an outer stator diameter of 8 mm, an outer rotor diameter of 4 mm, and a stack length of 5 mm. This research employs a topological method and JMAG-Designer Ver.22.0 electromagnetic analysis software to enhance the rotor design for high output torque and low torque ripple. The final design achieves an average torque of 174 μN-m and a torque ripple of 40%, which is lower than those of any two-phase motor reported in the literature. The two-phase FSM has been fabricated, assembled, and tested to demonstrate its feasibility. Full article

Environmental pollution from organic dyes such as malachite green and rhodamine B poses significant threats to ecosystems and human health due to their toxic properties. The rapid detection of these contaminants with high sensitivity and selectivity is crucial and can be effectively achieved using nonlinear optical methods. In this study, we combine the Simplified Bond Hyperpolarizability Model (SBHM) and molecular docking (MD) simulations to investigate the Second-Harmonic Generation (SHG) intensity of organic dyes on a silicon (Si(001)) substrate for nanoscale pollutant detection. Our simulations show good agreement with rotational anisotropy (RA) SHG intensity experimental data across all polarization angles, with a total error estimate of 3%. We find for the first time that the SBHM not only identifies the different organic pollutant dyes on the surface, as in conventional SHG detection, but can also determine their relative orientation and different concentrations on the surface. Meanwhile, MD simulations reveal that rhodamine B shows a strong adsorption affinity of $-10.4\mathrm{kcal}/\mathrm{mol}$ to a single-layer graphene oxide (GO) substrate, primarily through $\pi$-$\pi$ stacking interactions (36 instances) and by adopting a perpendicular molecular orientation. These characteristics significantly enhance SHG sensitivity. A nonlinear susceptibility analysis reveals good agreement between the SBHM and group theory. The susceptibility tensors confirm that the dominant contributions to the SHG signal arise from both the molecular structure and the surface interactions. This underscores the potential of GO-coated silicon substrates for detecting trace levels of organic pollutants with interaction distances ranging from $3.75\AA$ to $5.81\AA$. This approach offers valuable applications in environmental monitoring, combining the sensitivity of SHG with the adsorption properties of GO for nanoscale detection. Full article

To address the limitations of the current discrete element model of rice plants in terms of accurately reflecting structural differences and threshing characteristics, this study proposes a whole-rice-plant modeling method based on segmented hollow stalks and establishes a whole-rice-plant model that accurately represents the bending and threshing characteristics of the actual rice plant. Initially, based on the characteristics of the rice plant, the rice stalk was segmented into three sections of hollow stalks with distinct structures—namely, the primary stalk, the secondary stalk, and the tertiary stalk—ensuring that the model closely resembles actual rice plants. Secondly, the mechanical and contact parameters for each structure of the rice plant were measured and calibrated through mechanical and contact tests. Subsequently, utilizing the Hertz–Mindlin contact model, a multi-dimensional element particle arrangement method was employed to establish a discrete element model of the entire rice plant. The bending characteristics of the stalk and the threshing characteristics of the rice were calibrated using three-point bending tests and impact threshing tests. The results indicated calibration errors in the bending resistance force of 4.46%, 3.95%, and 2.51% for the three-section stalk model, and the calibration error for the rice model’s threshing rate was 1.86%, which can accurately simulate the bending characteristics of the stalk and the threshing characteristics of the rice plant. Finally, the contact characteristics of the model were validated through a stack angle verification test, which revealed that the relative error of the stacking angle did not exceed 7.52%, confirming the accuracy of the contact characteristics of the rice plant model. The findings of this study provide foundational models and a theoretical basis for the simulation of and analytical applications related to rice threshing and cleaning. Full article

The ability to measure vital signs using electromagnetic waves has been extensively investigated as a less intrusive method capable of assessing different biosignal sources while using a single device. On-body antennas, when directly coupled to the human body, offer a comfortable and effective alternative for daily monitoring. Nonetheless, on-body antennas are challenging to design primarily due to the high dielectric constant of body tissues. While the simulation process may often include a body model, a unique model cannot account for inter-individual variability, leading to discrepancies in measured antenna parameters. A potential solution is to increase the antenna’s bandwidth, guaranteeing the antenna’s impedance matching and robustness for all users. This work describes a new on-body microstrip antenna having a stacked structure with parasitic elements, designed and optimized using artificial intelligence (AI). By using an AI-driven design approach, a self-adaptive Bayesian neural network surrogate-model-assisted differential evolution for antenna optimization (SB-SADEA) method to be specific, and a stacked structure having parasitic elements and a defected ground structure with 27 tuneable design parameters, the simulated impedance bandwidth of the on-body antenna was successfully enhanced from 150 MHz to 1.3 GHz, while employing a single and simplified body model in the simulation process. Furthermore, the impact of inter-individual variability on the measured S-parameters was analyzed. The measured results relative to ten subjects revealed that for certain subjects, the SB-SADEA-optimized antenna’s bandwidth reached 1.6 GHz. Full article

Approaches to retain or improve wave-transparent composite properties received ongoing attention. Silica glass fiber composites are being utilized in wave transparency applications owing to their excellent dielectric properties. During operational service life, they are exposed to ambient and harsh environments, which degrade their performance and properties. The objective is to evaluate the progressive degradation of silica fiber wave-transparent composite material’s properties and overall performance. Silica fiber/epoxy wave-transparent composites (SFWCs) were fabricated by stacking high-silica glass cloth (HSG) plies via multi-layer compression and curing at 150 °C (14 hrs) and were investigated upon one-year real-time weathering and 20-year accelerated aging (Hallberg peck model). The morphology of one-year-aged SFWC composite was found to be better than that of 20-year-aged SFWC, where relatively weakened interfacial bonding and composite structure were observed. One year weathering the dielectric constant (ε_r) was increased to 4.34%, and dielectric loss (δ) was found to be 5.6%, whereas upon accelerated conditions (equivalent to 20 yrs of ambient conditions), ε_r was significantly raised 30.63% from its original value (3.2), and δ was increased 22.8% (0.035). In the 20-year aged SFWC composite, the maximum absorbed moisture was 3.1%. Tensile strength dropped from 147.8 MPa to 136.48 MPa, and compressive strength from 388.54 MPa to 374.41 MPa. Upon aging (from 1 year of weathering to 20 years of accelerated aging), SFWC composite properties and functional performance were lowered but remained reasonable. SFWC properties, as revealed by microscale characterization, can contribute to the determination of the impact of deterioration and useful service life in respective microelectronics wave transparency applications. Full article

Photonic crystals, which are important functional materials, are formed by the periodic arrangement of materials with different dielectric constants that have photonic bandgaps and localization properties. Their preparation methods are primarily physical and chemical. Physical methods include mechanical drilling, layer-by-layer stacking, and precision processing. Chemical methods primarily involve colloidal self-assembly methods. Various colloidal crystal self-assembly methods have been reported, each with its own advantages and disadvantages. Photonic crystals have important applications in many fields, such as optical communications, information technology, energy, biomedicine, and sensors, including high-performance optical fiber fabrication, photonic chip development, and solar cell efficiency enhancement. This paper reviews the latest progress in the preparation of photonic crystals using physical and self-assembly methods. Currently, the preparation and application of photonic crystals have made significant achievements; however, there are still challenges in terms of preparation accuracy, efficiency, cost, and application integration technology. With the future development of science and technology, breakthroughs are expected in novel structural development, preparation process optimization, and cross-field integration, which will continue to promote the progress of photonic crystals and social development. Full article