Search Results (63)

Transition-metal dichalcogenides have emerged as promising non-noble-metal electrocatalysts for efficient hydrogen production through the hydrogen evolution reaction (HER). In this work, we fabricated the graphitic carbon nitride-decorated cobalt diselenide (gC₃N₄-CoSe₂) nanocomposites via the facile hydrothermal method. The prepared gC₃N₄-CoSe₂ nanocomposites displayed an interconnected and aggregated morphology of gC₃N₄-decorated CoSe₂ nanoparticles with offering large surface area of 82 m²/g. The gC₃N₄-CoSe₂ nanocomposites exhibited excellent HER activity with a low overpotential (141 mV) and tiny Tafel slope (62 mV/dec) with excellent durability for 100 h at 10 mA/cm² in an alkaline electrolyte. These outstanding HER performances of gC₃N₄-CoSe₂ can be ascribed to the synergistic interaction between the electrochemically active porous CoSe₂ nanoparticles and the highly conductive gC₃N₄ nanosheets. These results indicate that the gC₃N₄-CoSe₂ nanocomposites hold promising and efficient HER electrocatalysts for sustainable green hydrogen production. Full article

The development of Micro-electro-magnetic Vibration Energy Harvesters (MEMVEHs) plays a crucial role in advancing self-powered nanophotonic, nanoelectronic, and nanosensor systems. As energy autonomy becomes critical for miniaturized devices, MEMVEHs offer a sustainable power source for low-power nanodevices operating in wireless sensor networks, wearable electronics, and biomedical implants. This study provides a comparative assessment of MEMVEH technologies and evaluates their integration potential within next-generation nanoscale systems, enabling enhanced performance, longevity, and energy efficiency of emerging nanotechnologies. Electromagnetic vibration energy harvesters (EMEHs) based on microelectromechanical system (MEMS) technology are promising solutions for powering small-scale, autonomous electronic devices. In this study, two electromagnetic vibration energy harvesters based on microelectromechanical (MEMS) technology are presented. Two models with distinct vibration structures were designed and fabricated. A permanent magnet is connected to a silicon vibration structure (resonator) and a tiny wire-wound coil as part of the energy harvester. The coil has a total volume of roughly 0.8 cm³. Two energy harvesters with various resonators are tested and compared. Model A’s maximum load voltage is 163 mV, whereas Model B’s is 208 mV. A maximum load power of 59.52 μW was produced by Model A at 347 Hz across a 405 Ω load. At 311.4 Hz, Model B produced a maximum load power of 149.13 μW while accelerating by 0.4 g. Model B features a larger working bandwidth and a higher output voltage than Model A. Model B performs better than Model A in comparable experimental settings. Simple study revealed that Model B’s electromagnetic energy harvesting produced superior outcomes. Additionally, it indicates that a nonlinear spring may be able to raise the output voltage and widen the frequency bandwidth. Full article

Wearable conductive hydrogel sensors, which are highly convenient, have attracted attention for their great potential in human motion monitoring and smart healthcare. However, the self−adhesive properties, sensing performance, and stability of traditional hydrogels are not ideal, which seriously hinders their use in monitoring and diagnosing joints throughout the human body. Here, CaCl₂ is used to crosslink PVA to improve its self−adhesive properties, and it is then combined with a CNT conductive network. Next, a cyclic freeze–thaw strategy is utilized to fabricate a wearable PVA−Ca−CNT hydrogel with excellent self-adhesive properties and stability. PVA−Ca−CNT hydrogels can adhere to various substrates, with a maximum self-adhesion strength of 398 kPa and a unit adhesion energy of as high as 305 μJ cm⁻². Furthermore, the CNT three−dimensional network enhances the tensile strength to 110 kPa, with almost no hysteresis. Based on resistance changes, PVA−Ca−CNT hydrogel exhibits a sensitivity of up to 11.11 as a strain sensor as well as a response to strain stimuli within 180 ms. When PVA−Ca−CNT hydrogel is adhered to the surface of human skin, it operates as a sensor for monitoring human movement. Not only can it accurately monitor the movement positions of major joints in the human body, it can also accurately identify tiny movements of the fingers and be used as a finger Morse code output device, which demonstrates the enormous potential of human motion monitoring systems based on self−adhesive hydrogel sensors in practical applications. Full article

Asphalt plant reclaimed powder is a common solid waste in road engineering. Reusing reclaimed powder as filler holds significant importance for environmental protection and resource conservation. The key factors affecting the feasibility of reclaimed powder reuse are its acidity/alkalinity and cleanliness. Traditional evaluation methods, such as the methylene blue test and plasticity index, can assess reclaimed powder properties to guide its recycling. However, these methods suffer from inefficiency, strong empirical dependence, and high variability. To address these limitations, this study proposes a rapid and precise evaluation method for reclaimed powder properties based on Fourier transform infrared spectroscopy (FTIR). To do so, five field-collected reclaimed powder samples and four artificial samples were evaluated. Scanning electron microscopy (SEM), X-ray fluorescence spectroscopy (XRF), and X-ray diffraction (XRD) were employed to characterize their microphase morphology, chemical composition, and crystal structure, respectively. Subsequently, FTIR was used to establish correlations between key acidity/alkalinity, cleanliness, and multiple characteristic peak intensities. Representative infrared characteristic peaks were selected, and a quantitative functional group index (Is) was proposed to simultaneously evaluate acidity/alkalinity and cleanliness. The results indicate that reclaimed powder primarily consists of tiny, crushed stone particles and dust, with significant variations in crystal structure and chemical composition, including calcium carbonate, silicon oxide, iron oxide, and aluminum oxide. Some samples also contained clay, which critically influenced the reclaimed powder properties. Since both filler acidity/alkalinity and cleanliness are affected by clay (silicon/carbon ratio determining acidity/alkalinity and aluminosilicate content affecting cleanliness), this study calculated four functional group indices based on FTIR absorption peaks, namely the Si-O-Si stretching vibration (1000 cm⁻¹) and the CO₃²⁻ asymmetric stretching vibration (1400 cm⁻¹). These indices were correlated with conventional testing results (XRF for acidity/alkalinity, methylene blue value, and pull-off strength for cleanliness). The results show that the Is index exhibited strong correlations (R² = 0.89 with XRF, R² = 0.80 with methylene blue value, and R² = 0.96 with pull-off strength), demonstrating its effectiveness in predicting both acidity/alkalinity and cleanliness. The developed method enhances reclaimed powder detection efficiency and facilitates high-value recycling in road engineering applications. Full article

Porous intermetallic compounds have the properties of porous materials as well as a combination of covalent and metallic bonds, and they exhibit high porosity, structural stability, and corrosion resistance. In this work, a porous TiNi₃ intermetallic compound was fabricated through reactive synthesis of elemental powders. Next, detailed studies of its phase composition and pore structure characteristics at different sintering temperatures, as well as its corrosion behavior against an alkaline environment, were carried out. The results show that the as-prepared porous TiNi₃ intermetallic compound has abundant pore structures, with an open porosity of 56.5%, which can be attributed to a combination of the bridging effects of initial powder particles and the Kirkendall effect occurring during the sintering process. In 1 M KOH solution, a higher positive corrosion potential (−0.979 V_SCE) and a lower corrosion current density (1.18 × 10⁻⁴ A∙cm⁻²) were exhibited by the porous TiNi₃ intermetallic compound, compared to the porous Ni, reducing the thermodynamic corrosion tendency and the corrosion rate. The corresponding corrosion process is controlled by the charge transfer process, and the increased charge transfer resistance value (713.9 Ω⋅cm²) of TiNi₃ makes it more difficult to charge-transfer than porous Ni (204.5 Ω⋅cm²), thus decreasing the rate of electrode reaction. The formation of a more stable passive film with the incorporation of Ti contributes to this improved corrosion resistance performance. Full article

Pepper is a vital crop with extensive agricultural and industrial applications. Accurate phenotypic measurement, including plant height and stem diameter, is essential for assessing yield and quality, yet manual measurement is time-consuming and labor-intensive. This study proposes a deep learning-based phenotypic measurement method for peppers. A Pepper-mini dataset was constructed using offline augmentation. To address challenges in multi-plant growth environments, an improved YOLOX-tiny detection model incorporating a CA attention mechanism was developed, achieving a mAP of 95.16%. A detection box filtering method based on Euclidean distance was introduced to identify target plants. Further processing using HSV threshold segmentation, morphological operations, and connected component denoising enabled accurate region selection. Measurement algorithms were then applied, yielding high correlations with true values: $R^2$ = 0.973 for plant height and $R^2$ = 0.842 for stem diameter, with average errors of 0.443 cm and 0.0765 mm, respectively. This approach demonstrates a robust and efficient solution for automated phenotypic analysis in pepper cultivation. Full article

A new instrument for label-free measurements based on optical Low-Q Whispering Gallery Modes (WGMs) for various applications is used for a detailed study of the deposition and release of Layer-by-Layer polymer coatings. The two selected coating pairs interact either via hydrogen bonding or electrostatic interactions. Their assembly was followed by common Quartz Crystal Microbalance (QCM) technology and the Low-Q WGMs. In contrast to planar QCM sensor chips of 1 cm, the WGM sensors are fluorescent spherical beads with diameters of 10.2 µm, enabling the detection of analyte quantities in the femtogram range in tiny volumes. The beads, with a very smooth surface and high refractive index, act as resonators for circular light waves that can revolve up to 10,000 times within the bead. The WGM frequencies are highly sensitive to changes in particle diameter and the refractive index of the surrounding medium. Hence, the adsorption of molecules shifts the resonance frequency, which is detected by a robust instrument with a high-resolution spectrometer. The results demonstrate the high potential of the new photonic measurement and its advantages over QCM technology, such as cheap sensors (billions in one Eppendorf tube), simple pre-functionalization, much higher statistic safety by hundreds of sensors for one measurement, 5–10 times faster analysis, and that approx. 25, 000 fewer analyte molecules are needed for one sensor. In addition, the deposited molecule amount is not superposed by hydrated water as for QCM. A connection between sensors and instruments does not exist, enabling application in any transparent environment, like microfluidics, drop-on slides, Petri dishes, well plates, cell culture vasculature, etc. Full article

As the most promising high energy density technology, lithium metal batteries are associated with serious interfacial challenges because the electrolytes employed are unable to meet the requirements of both electrodes simultaneously, namely, the systems that work for Li metal are highly likely to be unsuitable for the cathode, and vice versa. In this study, we investigate the synergistic effects of lithium bis (oxalate) borate (LiBOB), fluoroethylene carbonate (FEC) and adiponitrile (ADN) to develop a formula that is compatible with both elements in the battery. The solid–electrolyte interphase (SEI) multi-layer generated from LiBOB and FEC successfully protects the electrolyte from the lithium and suppresses the decomposition of ADN on lithium, identified by the tiny amounts of isonitriles on the surface of the anode. Simultaneously, most of the ADN molecules remain and protect the cathode particles via the absorption layer of the nitrile groups, in the same way that this process works in commercial lithium-ion batteries. Benefiting from the stable interfacial films formed synchronously on the anode and cathode, the Li/LiNi_0.8Co_0.1Mn_0.1O₂ cells with an area capacity of ~3 mAh cm⁻² operate stably beyond 250 cycles and target the accumulated capacity to levels as high as ~653.4 mAh cm⁻². Our approach demonstrates that electrolyte engineering with known additives is a practical strategy for addressing the challenges of lithium batteries. Full article

Three small donor molecule materials (S1, S2, S3) based on dithiophene [2,3-d:2′,3′-d′]dithiophene [1,2-b:4,5-b′]dithiophene (DTBDT) utilized in this study were synthesized using the Vilsmeier–Haack reaction, traditional Stille coupling, and Knoevenagel condensation. Then, a variety of characterization methods were applied to study the differences in optical properties and photovoltaic devices among the three. By synthesizing S2 using a thiophene π-bridge based on S1, the blue shift in ultraviolet absorption can be enhanced, the band gap and energy level can be reduced, the open circuit voltage (V_OC) can be increased to 0.75 V using the S2:Y6 device, and a power conversion efficiency (PCE) of 3% can be achieved. Also, after developing the device using Y6, S3 introduced the alkyl chain of thiophene π-bridge to S2, which improved the solubility of tiny donor molecules, achieved the maximum short-circuit current (J_SC = 10.59 mA/cm²), filling factor (FF = 49.72%), and PCE (4.25%). Thus, a viable option for future design and synthesis of small donor molecule materials is to incorporate thiophene π-bridges into these materials, along with alkyl chains, in order to enhance the device’s morphology and charge transfer behavior. Full article

Recently, the application of two–dimensional (2D) piezoelectric materials has been seriously hindered because most of them possess only in–plane piezoelectricity but lack out–of–plane piezoelectricity. In this work, using first–principles calculation, by atomic substitution of penta–graphene (PG) with tiny out–of–plane piezoelectricity, we design and predict stable 2D X–PG (X = Si or Ge) semiconductors with excellent in–plane and out–of–plane piezoelectricity and extremely high in–plane hole mobility. Among them, Ge–PG exhibits better performance in all aspects with an in–plane strain piezoelectric coefficient d₁₁ = 8.43 pm/V, an out–of–plane strain piezoelectric coefficient d₃₃ = −3.63 pm/V, and in–plane hole mobility μ_h = 57.33 × 10³ cm² V⁻¹ s⁻¹. By doping Si and Ge atoms, the negative Poisson’s ratio of PG approaches zero and reaches a positive value, which is due to the gradual weakening of the structure’s mechanical strength. The bandgaps of Si–PG (0.78 eV) and Ge–PG (0.89 eV) are much smaller than that of PG (2.20 eV), by 2.82 and 2.47 times, respectively. This indicates that the substitution of X atoms can regulate the bandgap of PG. Importantly, the physical mechanism of the out–of–plane piezoelectricity of these monolayers is revealed. The super–dipole–moment effect proposed in the previous work is proved to exist in PG and X–PG, i.e., it is proved that their out–of–plane piezoelectric stress coefficient e₃₃ increases with the super–dipole–moment. The e₃₃–induced polarization direction is also consistent with the super–dipole–moment direction. X–PG is predicted to have prominent potential for nanodevices applied as electromechanical coupling systems: wearable, ultra–thin devices; high–speed electronic transmission devices; and so on. Full article

Laser powder bed fusion allows the production of complex geometries and eases the shaping of difficult-to-transform materials, such as near-equiatomic Ti-Ni shape memory alloys. In this study, a numerical model was used to select 11 sets of printing parameters with different volumetric energy densities (VEDs) and build rates (BRs) to produce bulk Ti-50.26at%Ni alloy specimens. The manufactured specimens were studied in terms of their structural integrity, printed density, chemical composition, transformation temperatures, and crystalline phases. At high VEDs and low BRs, a significant decrease in the nickel content was observed. VED = 90 J/mm³ and BR = 10 cm³/h yielded a printed density of 99.94% and an austenite finish temperature of Af = 26.3 °C. The same printing conditions were used to produce 60% porous diamond and gyroid lattice structures. After heat treatment at 500 °C for 30 min, the diamond lattices manifested larger apparent recovery strains (7 vs. 6%), higher compliance (2.9 vs. 3.4 GPa), and similar yield stresses (~48 MPa) compared to their gyroid equivalents. The numerical model predicted that at an equivalent apparent compression strain of 6%, only a ~2% volume fraction of the diamond lattice material underwent plastic deformation as compared to ~20% for its gyroid equivalent. Full article

In this study, under the limited volume of 18 cm × 18 cm × 21 cm, a small-sized mobile robot is designed and implemented. It consists of a CPU, a GPU, a 2D LiDAR (Light Detection And Ranging), and two fisheye cameras to let the robot have good computing processing and graphics processing capabilities. In addition, three functions of road detection, sign recognition, and obstacle avoidance are implemented on this small-sized robot. For road detection, we divide the captured image into four areas and use Intel NUC to perform road detection calculations. The proposed method can significantly reduce the system load and also has a high processing speed of 25 frames per second (fps). For sign recognition, we use the YOLOv4-tiny model and a data augmentation strategy to significantly improve the computing performance of this model. From the experimental results, it can be seen that the mean Average Precision (mAP) of the used model has increased by 52.14%. For obstacle avoidance, a 2D LiDAR-based method with a distance-based filtering mechanism is proposed. The distance-based filtering mechanism is proposed to filter important data points and assign appropriate weights, which can effectively reduce the computational complexity and improve the robot’s response speed to avoid obstacles. Some results and actual experiments illustrate that the proposed methods for these three functions can be effectively completed in the implemented small-sized robot. Full article

‘Hangju’ is a variety of Chrysanthemum × morifolium Ramat. with both edible and medicinal value, cultivated as a traditional Chinese medicine for four centuries. The cultivation of ‘Hangju’ is currently at risk due to waterlogging, yet there is a lack of comprehensive understanding regarding its response to waterlogging stress. This study compared the waterlogging-tolerant ‘Hangju’ variety Enhanced Waterlogging Tolerance (EWT) with the waterlogging-sensitive variety CK (‘zaoxiaoyangju’). EWT exhibited a more developed aeration tissue structure and demonstrated rapid growth regarding the adventitious roots following waterlogging. The time-course transcriptome analysis indicated that EWT could swiftly adjust the expression of the genes involved in the energy metabolism signaling pathways to acclimate to the waterlogged environment. Through WGCNA analysis, we identified Integrase-Type DNA-Binding Protein (CmTINY2) as a key factor in regulating the waterlogging tolerance in EWT. CmTINY2, a transcription factor belonging to the ethylene-responsive factor (ERF) subfamily III, operated within the nucleus and activated downstream gene expression. Its role in enhancing the waterlogging tolerance might be linked to the control of the stomatal aperture via the Ethylene-Responsive Element (ERE) gene. In summary, our research elucidated that the waterlogging tolerance displayed by EWT is a result of a combination of the morphological structure and molecular regulatory mechanisms. Furthermore, the study of the functions of CmTINY2 from ERF subfamily III also broadened our knowledge of the role of the ERF genes in the waterlogging signaling pathways. Full article

In vitro mass propagation of apple plants plays an important role in the rapid multiplication of genetically uniform, disease-free scions and rootstocks with desired traits. Successful micropropagation of apple using axillary shoot cultures is influenced by several factors, the most critical of which is the cytokinin included in the culture medium. The impact of medium composition from single added cytokinins on shoot proliferation of apple scion Húsvéti rozmaring cultured on agar-agar gelled Murashige and Skoog medium fortified with indole butyric acid and gibberellic acid was investigated. The optimum concentration for efficient shoot multiplication differs according to the type of cytokinin. The highest significant multiplication rate (5.40 shoots/explant) was achieved using 2.0 μM thidiazuron while the longest shoots (1.80 cm) were observed on the medium containing benzyladenine at a concentration of 2.0 μM. However, application of either thidiazuron or benzyladenine as cytokinin source in the medium resulted in shoots of low quality, such as stunted and thickened shoots with small leaves. In the case of benzyladenine riboside, the 8 μM concentration was the most effective in increasing the multiplication rate (4.76 shoots/explant) but caused thickened stem development with tiny leaves. In the present study, meta-topolin was shown to be the most effective cytokinin that could be applied to induce sufficient multiplication (3.28 shoots/explant) and high-quality shoots along with shoot lengths of 1.46 cm when it was applied at concentrations of 4 μM. However, kinetin was the least active cytokinin; it practically did not induce the development of new shoots. The superior cytokinin for in vitro axillary shoot development of apple scion Húsvéti rozmaring with high-quality shoots was the meta-topolin, but it may be different depending on the variety/genotype under study. Full article

Antimicrobial resistance (AMR) has become a crucial global health issue. Antibiotic-resistant bacteria can survive after antibiotic treatments, lowering drug efficacy and increasing lethal risks. A microfluidic water-in-oil emulsion droplet system can entrap microorganisms and antibiotics within the tiny bioreactor, separate from the surroundings, enabling independent assays that can be performed in a high-throughput manner. This study presents the development of a label-free dielectrophoresis (DEP)-based microfluidic platform to sort droplets that co-encapsulate Escherichia coli (E. coli) and ampicillin (Amp) and droplets that co-encapsulate Amp-resistant (AmpR) E. coli with Amp only based on the conductivity-dependent DEP force (F_DEP) without the assistance of optical analyses. The 9.4% low conductivity (LC) Luria–Bertani (LB) broth diluted with 170 mM mannitol can maintain E. coli and AmpR E. coli growth for 3 h and allow Amp to kill almost all E. coli, which can significantly increase the LCLB conductivity by about 100 μS/cm. Therefore, the AmpR E. coli/9.4%LCLB/Amp where no cells are killed and the E. coli/9.4%LCLB/Amp-containing droplets where most of the cells are killed can be sorted based on this conductivity difference at an applied electric field of 2 MHz and 100 V_pp that generates positive F_DEP. Moreover, the sorting ratio significantly decreased to about 50% when the population of AmpR E. coli was equal to or higher than 50% in droplets. The conductivity-dependent DEP-based sorting platform exhibits promising potential to probe the ratio of AmpR E. coli in an unknown bacterial sample by using the sorting ratio as an index. Full article