Dense Surface Research Articles

High-Performance Vis–NIR Photodetectors Based on Two-Dimensional Bi2Te3 Thin Film and Applications

Two-dimensional materials have excellent optoelectronic properties and have great significance in the field of photodetectors. We have prepared a thin film photodetector based on bismuth telluride (Bi2Te3) topological insulator using dual-temperature-zone vapor deposition technology. Due to the high-quality lattice structure of Bi2Te3 and the uniform and dense surface morphology of the Bi2Te3 thin film, the device exhibits excellent photoelectric response and Vis–NIR spectral range. Under 405 nm illumination, the responsivity is 5.6 mA/W, the specific detectivity is 1.22 × 107 Jones, and the response time is 262/328 ms. We designed a photodetector single-point scanning imaging system and successfully achieved high-resolution imaging at a wavelength of 532 nm. This work provides guidance for the application of two-dimensional materials, especially Bi2Te3, in the fields of photodetectors and imaging.

Innovative multiphase ultrasonic-assisted method for high-purity, stable, and cost-effective copper nanowire synthesis

The synthesis of copper nanowires (CuNWs) using modified polyols with hexadecylamine or octadecylamine as capping agents, known for their ease of operation, rapid reaction, and suitability for mass production, often encounters challenges such as the presence of copper particles, numerous copper nanorods, difficulty in purifying organic compounds, and air instability as by-products. In addressing these issues, this study introduces an innovative multiphase ultrasonic-assisted separation method. By utilizing ultrasound to accelerate the dissolution of hexadecylamine and facilitate the separation movement of CuNWs and by-products in hydrophilic and hydrophobic phases, the aim of achieving high purification of CuNWs is realized. Through the introduction of an ultra-thin hexadecylamine layer (~ 3.5 nm) on the surface of CuNWs and leveraging the active adsorption of silver seed crystals, combined with the control CuNWs reaction concentration, silver-coated CuNWs with a dense and uniform surface thickness of 12–15 nm are obtained. By enhancing purity, stability, and cost-effectiveness, this research represents a significant advancement in the field of one-dimensional nanowires and their devices.

Preparation and Characterization of Superabsorbents Based on Durian Seed Starch (Durio zibethinus) and Carboxymethyl Cellulose Using Citric Acid Crosslinking

Superabsorbents are materials that can absorb a liquid beyond its initial volume. Natural polymer-based superabsorbents can be obtained by combining CMC and durian seed starch. The combination of these two materials was cross-linked using varying amounts of citric acid: 0.0 grams, 0.2 grams, 0.4 grams, and 0.6 grams. The resulting superabsorbent has a cross-linking degree of about 41%, shows the presence of OH and CH groups, has a rough and dense surface, and a maximum water absorption capacity of 4130% with a water absorption rate of 41.3 g/g. Durian seed starch has potential as a superabsorbent material.

Sintering Behavior of Molybdenite Concentrate During Oxidation Roasting Process in Air Atmosphere: Influences of Roasting Temperature and K Content.

Sintering is a common phenomenon, which often takes place during the oxidation roasting process of molybdenite concentrate in multiple-hearth furnaces. The occurrence of sintering phenomena has detrimental effects on the product quality and the service life of the furnace. In this work, the influence of two key factors (roasting temperature and K content) on the sintering behavior is investigated using molybdenite concentrate as the raw material. Different technologies such as XRD, FESEM-EDS, and phase diagrams are adopted to analyze the experimental data. The results show that the higher the roasting temperature is, the greater the mass loss and the more serious the sintering degree will be. The results also show that with the increase in K content, the mass loss of the raw material is first increased and then decreased, while its sintering degree is still gradually increased. The sintering products obtained during the oxidation roasting process are often tightly combined with the bottom of the used crucible with a smooth and dense surface structure, while their internal microstructures are very complicated, which not only includes numerous MoO3 species, but also unoxidized MoS2, Mo sub-oxide, SiO2, and a variety of molybdates. Among them, both MoO3 and molybdates can be easily dissolved into the ammonia solution, leading to a residue mainly composed of SiO2 and CaMoO4. This study also finds that the sintering phenomenon is caused by the increase in local temperature and the formation of various low-melting-point eutectics. It is suggested that decreasing the roasting temperature and K content, especially the K content, are effective methods for reducing the sintering degree of molybdenite concentrate during the oxidation roasting process.

A highly branched glucomannan from the fruiting body of Schizophyllum commune: Structural characteristics and antitumor properties analysis

In this study, a highly branched glucomannan (SCP-1) from Schizophyllum commune fruiting body with good solubility was isolated, and its structural characteristics and antitumor properties were analyzed. The monosaccharides of SCP-1 were fucose, glucosamine hydrochloride, galactose, glucose and mannose with a relative molar ratio of 14:6:210:593:177, and the molecular weight (Mw) of SCP-1 was 15.1 kDa. SCP-1 showed a rough and dense surface, and it was aggregated to particles in distilled water, though it might have triple-helix conformation. The main backbone chain of SCP-1 was →[3)-β-D-Glcp-(1]3→3)-β-D-Glcp-(1→2)-α-D-Manp-(1→2)-α-D-Manp-(1→3)-α-D-Glcp-(1→ and three sides chains including α-D-Glcp-(1→[6)-β-D-Glcp-(1]2→, α-D-Glcp-(1→3)-α-D-Manp-(1→ and α-D-Glcp-(1→[6)-α-D-Galp-(1]3→ were linked with 1,6-glycosidic bond, which was significantly different with the schizophyllan isolated from the mycelia of S. commune. SCP-1 could significantly inhibit the growth of A549 cells, the inhibition rate reached 41.62 % and the percentage of cells in S phase increased from 27.17 % to 56.40 % (400 μg/mL, 48 h). Moreover, SCP-1 could induce cell apoptosis and the total apoptosis rate reached 28.13 %. SCP-1 exerted apoptosis inducing effect probably by reducing the expression ratio of Bcl-2/Bax and the p-PI3K, p-Akt and p-mTOR expression level. The results showed that SCP-1 might have the potential to act as an antitumor agent for lung cancer therapy.

Calcium alginate-encapsulated propolis microcapsules: Optimization, characterization, and preservation effects on postharvest sweet cherry

The increasing consumption of fresh fruits and vegetables has led to the development of eco-friendly and active preservation materials which have slow-release effect of antioxidant/antifungal agents. The propolis microcapsules (PM), utilizing calcium alginate as the wall material, incorporating ethanolic extract of propolis (EEP) as the core material, were prepared by ionic gelation method and conducted a investigation of its characteristics After optimization by single factor experiment and theoretical response models, PM which was prepared by dropping 9.3 g L−1 100 mL sodium alginate solution containing 9.8 mL EEP into 0.22 mol L−1 calcium chloride solution showed an encapsulation efficiency of 69.29±1.12 %. Prepared microcapsules were spherical with a dense surface which protected propolis well from the environment, retained a large number of bio-active compounds and improve thermal stability of propolis. Moreover, the microcapsules exhibited good slow-release effect and good inhibitory influence on the development of Alternaria Alternata growth which the colony diameter of the control was 41.38 % higher than the treatment at day six. With 5.0 g PM placed in the small non-woven bag in the application on sweet cherries with non-direct contact method, the decay rate and weight loss of fruits were reduced by 47.5 % and 17.6 %, concurrently the PM also effectively maintain the good appearance, hardness, antioxidant capacity by slowing the reduction in the content of total phenols, flavonoids and enzymatic activities. Therefore, the PM with superior antioxidant and antifungal capacity have the great potential to design as a practical active materials for fruits preservation.

Photovoltaic Properties of Bismuth Vanadate/Bismuth Ferrite Heterostructures Prepared by Spin Coating

This study investigates the photovoltaic performance of bismuth vanadate (BiVO₄)/bismuth ferrite (BiFeO₃) heterostructures. By varying the pre-annealing temperature of the BiVO₄ layer, we have achieved significant enhancement in the open-circuit voltage (Voc) with the spontaneous formation of the polarized Bi4V2O11 interfacial layer. X-ray diffraction analysis confirms a pure rhombohedral distorted perovskite structure for BiFeO₃ and a monoclinic crystallographic nature for BiVO₄. SEM analysis exhibits a porous structure with small spherical grains in the BiVO₄ layer, with the dense and smooth surface of the BiFeO₃ layer. The heterostructures represented in a red-shifted absorption edge are compared with the individual materials, which indicates an improved light absorption. Tauc plot analysis has yielded the direct bandgap values of 1.88 eV and 1.83 eV for the BiVO4 annealing temperatures at 150 and 500°C, respectively. The overall power conversion efficiency (η) has remained low at 0.003% and 0.005%, demonstrating the potential of interfacial engineering to optimize the photovoltaic properties of BiVO₄/BiFeO₃ heterostructures.

Time-dependent corrosion behavior of EH36 steel caused by Pseudomonas aeruginosa based on big data monitoring technology

Marine microbial corrosion poses a significant threat to the safe service of marine engineering equipment. Previous studies have often failed to thoroughly analyze the continuous and prolonged microbial corrosion process, resulting in an incomplete understanding of microbial corrosion mechanisms involved at various stages and the development of ineffective control strategies. This study employed a corrosion big data online real-time monitoring technique to investigate the time-dependent corrosion behavior of EH36 steel caused by Pseudomonas aeruginosa in aerobic environments over a 30-d incubation period. It was found that P. aeruginosa accelerated the corrosion of EH36 steel in the early stages by enhancing the cathodic oxygen reduction process. As oxygen levels declined, P. aeruginosa transitioned from aerobic to anaerobic respiration, promoting corrosion through biocatalytic nitrate reduction. In the later stages, the reduction in sessile cell counts, extreme low oxygen concentration, and dense surface film increased the charge transfer and film resistances, ultimately leading to corrosion inhibition. The weight loss and electrochemical data confirmed the effectiveness of the big data monitoring technique in investigating microbial corrosion, which provides new approaches for diagnosing and preventing microbial corrosion.

Electrodeposition of Thin Film Cu-Zn-Sn Alloy for Water Splitting Application

An energy transition to renewable energy sources is necessary due to the scarcity of fossil fuels and their detrimental effects on the environment. Water splitting process is one of the practical and effective way that does not occur spontaneously. This study investigates catalytic activity of Cu-Zn-Sn (CZT) photocatalyst in hydrogen evolution and oxygen evolution reaction. The CZT deposited with varied electrolyte’s pH of 6 and 9 on indium tin oxide substrate at the room temperature for 600 seconds. According to the X-ray diffraction patterns, there were Cu6Sn5, Cu5Zn8, and Sn metal phases with monoclinic, cubic, and cubic crystal systems. The scanning electron microscopy technique results of all CZT alloy sample showed a dense, non-uniform, and polycrystalline surface structure. The CZT alloys were found to have an average particle size of 0.35 μm. CZT alloys can produce a photocurrent density of 0.19 mA/cm² at a potential of 1.29 V vs RHE. the charge transfer resistance of CZT synthesized at pH 6 is lower (21.48 Ω) compared to pH 9 (28.36 Ω). The Tafel slope of HER for pH 9 CZT was -133 mV/dec, which was lower than that of pH 6 CZT (-88 mV/dec), indicating faster H2 production and corrosion resistance on pH 9 CZT.

Tissue spaces are reservoirs of antigenic diversity for Trypanosoma brucei.

The protozoan parasite Trypanosoma brucei evades clearance by the host immune system through antigenic variation of its dense variant surface glycoprotein (VSG) coat, periodically 'switching' expression of the VSG using a large genomic repertoire of VSG-encoding genes1-6. Recent studies of antigenic variation in vivo have focused near exclusively on parasites in the bloodstream6-8, but research has shown that many, if not most, parasites reside in the interstitial spaces of tissues9-13. We sought to explore the dynamics of antigenic variation in extravascular parasite populations using VSG-seq7, a high-throughput sequencing approach for profiling VSGs expressed in populations of T. brucei. Here we show that tissues, not the blood, are the primary reservoir of antigenic diversity during both needle- and tsetse bite-initiated T. brucei infections, with more than 75% of VSGs found exclusively within extravascular spaces. We found that this increased diversity is correlated with slower parasite clearance in tissue spaces. Together, these data support a model in which the slower immune response in extravascular spaces provides more time to generate the antigenic diversity needed to maintain a chronic infection. Our findings reveal the important role that extravascular spaces can have in pathogen diversification.

All‐SnO2‐Based Conformal Electron Transport Layer for Efficient Perovskite Solar Cells

AbstractThe fabrication of high‐performance perovskite solar cells on high‐haze fluorine‐doped tin oxide (FTO) substrates with superior light‐trapping capabilities necessitates a highly conformal electron transport layer at the bottom interface. Herein, a conformal low‐temperature processable all‐SnO2‐based electron transport layer (ETL) is successfully developed on high‐haze FTO by well‐anchoring a polyacrylic acid‐stabilized quantum dot‐SnO2 layer onto an atomic layer deposited SnO2 layer with a dense hydroxyl surface. The obtained ETL demonstrates excellent capabilities in simultaneously homogenizing the surface contact potential distribution, blocking hole transport, and suppressing non‐radiative recombination. Consequently, a champion device is achieved that delivers a remarkable power conversion efficiency (PCE) of up to 24.97%, with VOC × FF reaching 87.09% of the Shockley‐Queisser limit at a bandgap of 1.54 eV, which is the highest value among the ALD SnO2‐based PSCs. The homogeneous ETL further enabled the fabrication of a 1 cm2 PSC with a PCE of 23.18% and only a 10 mV loss in VOC compared to smaller‐area PSCs, showcasing its potential for large‐scale commercial applications.

A simulation study of deepwater ventilation in fjords through artificial downwelling

The pumping of less dense surface water into a deep layer, also termed artificial downwelling (AD), has demonstrated its effectiveness in ventilating basin water in a few fjords. Building on a previous experiment in By Fjord, we established a well-calibrated far-field hydrodynamic model to simulate bottom water circulation caused by AD implementation. Our simulations suggest that (1) laterally closed boundaries are crucial for AD to cause spatially uniform compensatory downwelling in the bottom water and that (2) dissolved oxygen delivered through downwelling can be sourced from both surface waters and below the pycnocline to enhance oxygen levels effectively. We propose a physical oxygen budget model to predict the temporal variability of deep-water oxygen levels, offering guidelines on the number of pipes and flow rates required for large-scale oxygenation. For small fjords (∼1 km2), a few pipes (each has a flow rate of 1 m3 s−1) may suffice, while medium-sized basins like Chesapeake Bay (∼1000 km2) may require several hundred pipes.

Design and performance of a foamed ceramic prepared by sintering using boron carbide as a foaming agent

To meet the requirements of microwave penetration in military applications, the technical potential of preparing foamed ceramics (FCs) with low permittivity and reduced preparation costs by using desalted sea sands as the main raw material and boron carbide (B4C) as a foaming agent was investigated. The results of the orthogonal experiment demonstrate that the FCs prepared from a material system containing 3 wt% B4C, 2 wt% Fe2O3 and 4 wt% Na2CO3 exhibit the optimal overall performance. The performance of the FCs is strongly influenced by the sintering temperature, but less so by the sintering time. The FCs sintered at 1000 °C for 10 min have a high total porosity of 72 %, a high compressive strength of 9.7 MPa due to their homogeneous internal pore structure with small pore diameter, a high closed porosity of 71 % due to their dense smooth surface and intact pore walls, and a low permittivity of (2.09–2.25)+j(0.014–0.019) in the X–band due to their high porosity and simple composition, indicating that they are a promising multifunctional material for microwave penetration.

Adaptive infrared patterns for microscopic surface reconstructions.

Multi-zoom microscopic surface reconstructions of operating sites, especially in ENT surgeries, would allow multimodal image fusion for determining the amount of resected tissue, for recognizing critical structures, and novel tools for intraoperative quality assurance. State-of-the-art three-dimensional model creation of the surgical scene is challenged by the surgical environment, illumination, and the homogeneous structures of skin, muscle, bones, etc., that lack invariant features for stereo reconstruction. An adaptive near-infrared pattern projector illuminates the surgical scene with optimized patterns to yield accurate dense multi-zoom stereoscopic surface reconstructions. The approach does not impact the clinical workflow. The new method is compared to state-of-the-art approaches and is validated by determining its reconstruction errors relative to a high-resolution 3D-reconstruction of CT data. 200 surface reconstructions were generated for 5 zoom levels with 10 reconstructions for each object illumination method (standard operating room light, microscope light, random pattern and adaptive NIR pattern). For the adaptive pattern, the surface reconstruction errors ranged from 0.5 to 0.7 mm, as compared to 1-1.9 mm for the other approaches. The local reconstruction differences are visualized in heat maps. Adaptive near-infrared (NIR) pattern projection in microscopic surgery allows dense and accurate microscopic surface reconstructions for variable zoom levels of small and homogeneous surfaces. This could potentially aid in microscopic interventions at the lateral skull base and potentially open up new possibilities for combining quantitative intraoperative surface reconstructions with preoperative radiologic imagery.

Enhanced Anti-Corrosion and Biological Performance of Plasma-Sprayed Nb/ZrO2/HA Coatings on ZK60 Mg Alloy

Niobium (Nb) and zirconium dioxide (ZrO2) were doped into hydroxyapatite (HA) to fabricate HA-based composite coatings prepared on a ZK60 magnesium alloy by plasma spraying technology to improve anti-corrosion and biocompatibility for clinical applications. The results revealed that the Nb-enriched coating exhibits fewer cracks and pores with a flat surface due to the decreased temperature gradient during spraying, and small needle-like structures can fill the cracks and pores in the ZrO2-contained coating, resulting in a more uniform and dense surface. Compared to coatings with only niobium or zirconium dioxide, the ZrO2/Nb/HA composite coating significantly enhanced the mechanical properties and corrosion resistance of the magnesium alloys. Among all the specimens, the ZrO2/HA coating and ZrO2/Nb/HA coating revealed high surface hardness values (327.73 HV and 293.80 HV, respectively). However, the higher hardness value made the ZrO2/HA coating fragile and more likely to crack, while the ZrO2/Nb/HA coating avoided this shortcoming and exhibited a more comprehensive performance. During immersion tests, the ZrO2/Nb/HA coating exhibited a gradual pH increase and minimal mass loss, and the cytocompatibility test demonstrated promising cellular activity.

Handling of porous road surfaces in traffic noise calculations with Nord2000

Using porous road surfaces can be an alternative to more traditional noise reduction measures. Two factors contribute to the fact that road noise can get lower than with a conventional dense road surface: the rolling noise emission decreases, and the sound-absorbing road surface can further reduce the level. In a traffic noise calculation with Nord2000, the influence of the road surface on the sound emission is specified using road surface corrections while the acoustic surface impedance of the road surface determines the ground attenuation. However, due to measurement technical reasons, porous road surface corrections will include some (undesirable) ground attenuation, leading to that the rolling noise emission might be underestimated. Another problem is that the impedance model in Nord2000 (Delany & Bazley) does not give correct results for porous road surfaces. These complications have been investigated with Nord2000 calculations using a program code extended to also include an impedance model capable of handling porous road surfaces (Hamet et al). The results have been used to formulate official Swedish recommendations on how porous road surfaces can be handled in traffic noise investigations with Nord2000.

Polyethylene glycol enhanced antibacterial activity of EDTA and ethyl maltol blended PLA against Staphylococcus aureus for biodegradable active packaging

Poly (lactic acid) (PLA) has limited promise as a bio-based antimicrobial packaging material due to its lack of plasticization, which limits antimicrobial agent release and antimicrobial efficiency. PLA were plasticized with polyethylene glycol (PEG) and blended with ethyl maltol or ethylenediaminetetraacetic acid (EDTA) as antibacterial agents by melt extrusion. The effects of combining PEG, EDTA, and ethyl maltol on sheet properties and antibacterial activity were investigated. Incorporation of ethyl maltol created a dense and smooth homogeneous surface, while EDTA addition caused large pores in the PLA sheet microstructure impacting swelling degree, water solubility and surface hydrophilicity. Fourier transform infrared (FTIR) spectroscopy and differential scanning calorimetry (DSC) showed that both ethyl maltol and EDTA addition modified the amorphous and crystalline phases of plasticized PLA. FTIR results suggested interaction between the functional groups of PLA chains, PEG, ethyl maltol or EDTA which affected the glass transition temperature (Tg), degree of crystallinity, and thermal stability of PLA. Adding PEG into PLA-EDTA enhanced antibacterial activity against Gram-positive Staphylococcus aureus (reduction of 1.35 log CFU/mL from the initial inoculum). The higher water solubility of sheets corresponded to a suitable release rate and sufficient amounts of antimicrobial compounds against Staphylococcus aureus. In vitro antifungal testing, PLA-PEG-EDTA sheets did not exhibit a clear zone of inhibition but delayed Penicillium sp. spore formation until day 5 of incubation. PEG plasticized PLA sheets functionalized with ethyl maltol and EDTA showed potential as active biomaterials against food-borne pathogen bacteria Staphylococcus aureus.

Influence mechanism of magnetron sputtering process parameters on diamond surface preprocessing interface for chip heat sink

The interface between diamond and aluminum is poor in wettability and solid solubility. The interface bonding can be improved effectively by plating metal elements on diamond surface combined with heat treatment. In this paper, the influence of adjustable process parameters on the quality of Mo layer modified by magnetron sputtering was studied based on orthogonal experiments, and Mo-coated diamond/aluminum composite materials were prepared by Spark Plasma Sintering (SPS). The results indicate that the deposition of Mo layer on the diamond surface proceeds through three stages: adsorption, surface diffusion, and stable nucleus growth, forming an initial thin film, followed by layer-by-layer stacking through repeated growth of these stages. Sputtering time and sputtering pressure are the main factors affecting the quality of the coating. Mo layers prepared under conditions of 30 min and 0.5 Pa exhibit uniform and dense surface and moderate thickness. After heat treatment, recrystallization forms equiaxed grains, and Mo2C is formed in reaction with diamond, effectively enhancing the interface bonding strength between diamond and aluminum. The thermal conductivity of the diamond/aluminum composite material reached 342 W/(mK).

Exploring the potential of fibrinogen hydrolysates as enhancers for myofibrillar protein gelation: Insights into molecular assembly behavior

This study explored the use of pig blood fibrinogen hydrolysates, enzymatically hydrolyzed with trypsin and flavorzyme, to enhance myofibrillar protein gels, addressing issues like poor gel strength and water loss in meat products. By incorporating varying concentrations of fibrinogen hydrolysates into myofibrillar proteins, heat-induced gels were prepared. The composite gels showed improved textural properties, rheological characteristics and water-holding capacity. Scanning electron microscopy and atomic force microscopy analyses revealed a uniform, dense surface and an orderly internal structure in the composite gels. The study also noted decreased α-helix and random coil and increased β-sheet and β-turn contents, indicating a more ordered secondary structure. Hydrophobic interactions and disulfide bonds were identified as key factors in enhancing gelation, and a model was proposed to explain these molecular effects. This research demonstrates a potential of fibrinogen hydrolysates to improve quality and structure of myofibrillar protein gels designed for high-quality meat products.

Flow behavior of polypropylene reactor powder in horizontal stirred bed reactors characterized by X-ray imaging

Horizontal stirred bed reactors (HSBRs) are widely used in the commercial production of polypropylene (PP). Despite their commercial significance, a comprehensive understanding of the flow behavior in HSBRs remains elusive, primarily due to the lack of detailed experimental data. This study investigates the influence of operating parameters on the particle flow behavior of two types of PP reactor powder in a laboratory-scale HSBR using X-ray imaging. Our results indicate that the overall flow behavior and phase holdup in the HSBR are dominated by agitation. Moreover, gas injection through the inlet points at the bottom of the HSBR results in spouting behavior, which can lead to reduced gas-solid contacting and, in extreme cases, complete bypass. Finally, the presence of liquid (in this study, isopropyl alcohol) adversely affects the flow behavior of the PP reactor powder due to liquid bridging at the contact points of particles. Powders that comprise particles with relatively small sizes and dense surface morphology are particularly prone to reduced flow behavior when exposed to liquid.