Search

The current emphasis in the advancement of space-based synthetic-aperture radar (SAR) is on lightweight payloads under 100 kg with resolutions surpassing 1 m. This focus is directed toward meeting the launch criteria for multiple satellites on a single rocket and cutting costs. This article discusses the creation and progress of a Ku-band SAR payload for the Taijing-4(03) satellite, launched on 23 January 2024 and accompanied by four other satellites. The SAR payload design was customized to meet the demands of a micro-nano satellite platform, resulting in a lightweight, flat design weighing less than 80 kg, seamlessly integrated with the plate-shaped satellite platform. The article also introduces a beam optimization strategy for the phased array SAR antenna, significantly boosting the SAR system's performance. The SAR payload provides various operating modes like slide-spot, strip, Scan 1, Scan 2, and others, with a maximum achievable resolution exceeding 1 m. Extensive in-orbit testing of the payload produced numerous high-quality SAR images with potential uses in emergency disaster mitigation, safeguarding ecosystems, monitoring forests, managing crops, tracking sea ice, and more. [ABSTRACT FROM AUTHOR]

Surgical sutures are necessary for the rotator cuff (RC) repair to reconnect the torn and degenerating cuff tendon to its footprint. Early‐stage immunomodulation, angiogenesis, and the progressive mechanobiological response encourage complex healing processes involving micro‐nano dimensional reconstruction, including tendon‐bone interface integration and tendon remodeling. However, commercially available sutures with mismatched micrometer‐scale diameters resulted in mechanobiological and biological deficiencies, severely impeding RC regeneration. We developed a bionic functional surgical suture (SS) with helical and hierarchical micro‐nano structures using nano‐ and micro‐Poly (DL‐lactide‐co‐glycolide) (PLGA) yarns (ny), which was subsequently crosslinked in situ with a temporary chemotactic (TC) layer of physiological fibrin networks (TC‐nySS). The TC‐nySS has both mechanobiological and biological advantages: 1) biomimetic helical and hierarchical micro‐nano structures showed progressive degradation behavior, inducing the incremental mechanobiological response of the repaired tissues; 2) outer TC layer of biochemical modification by fibrin networks supplied dual‐functions of angiogenesis and immunomodulation at the early stage, subsequently resulting in timely vascularization and inflammatory regressions due to superior degradation behavior of the constructs. Consequently, TC‐nySS with structural and biochemical designs that elicit process‐matching mechanobiological and biological responses tailored to the RC regeneration successfully achieved the complex healing processes, including superior tendon‐bone interface integration and tendon remodelling. [ABSTRACT FROM AUTHOR]

[Display omitted] Black phosphorus quantum dots (BPQDs)-based materials possess excellent photocatalytic efficiency; however, they often present a loss of photo-induced carriers and random active sites in electron transfer of heterojunctions, thus restricting the enhancement of hydrogen (H 2) evolution and their potential application. In this study, a micro-nano ZnIn 2 S 4 /BPQDs (MN-ZISBP) composite is constructed to enable specific orientation and self-distribution of photoelectrons transferred from ZnIn 2 S 4 (ZIS) to BPQDs. The relationship between photoelectron transfer and H 2 evolution efficiency is investigated via experiments and density functional theory (DFT) calculations. MN-ZISBP with a nanorod-like structure presents an H 2 evolution rate of 1207 μmol/g/h and is higher than that of the sheet-shaped (S-ZISBP, 1023 μmol/g/h) and flower-like composites (F-ZISBP, 744 μmol/g/h) under visible light irradiation. The MN-ZISBP composite with a lower conduction band level and larger specific surface area increases the number of active sites on BPQDs via "self-distribution" for H 2 evolution. Finally, the electron transfer direction and bonding orbitals of MN-ZISBP are calculated using the work function and density of states results to verify the above conclusions. The novel construction technique and photocatalytic mechanism of MN-ZISBP reported in this study provide significant insights into the BPQDs-based photocatalysts for H 2 evolution. [ABSTRACT FROM AUTHOR]

A magnetorheological fluid (MR fluid) is mainly composed of soft magnetic particles, surfactants, and the base carrier fluid. Among these, soft magnetic particles and the base carrier fluid influence the MR fluid significantly in a high-temperature environment. Therefore, a study was carried out to investigate the changes in the properties of soft magnetic particles and base carrier fluids in high-temperature environments. On this basis, a novel magnetorheological fluid with high-temperature resistance was prepared, and the novel magnetorheological fluid had excellent sedimentation stability, of which the sedimentation rate was only 4.42% after heat treatment at 150 °C followed by one-week placement. At 30 °C, the shear yield stress of the novel fluid was 9.47 kPa under the magnetic field of 817 mT: higher than the general magnetorheological fluid with the same mass fraction. Moreover, its shear yield stress was less affected by the high-temperature environment, reducing by only 4.03% from 10 °C to 70 °C. The novel MR fluid can be applied to a high-temperature environment, effectively expanding the application range of MR fluid. [ABSTRACT FROM AUTHOR]

Low soil aeration often causes hypoxia stress in the root zone, deteriorating the normal metabolic activities and growth of crops. Micro-nano oxygenation technology can be expected to serve as the potential type of irrigation water oxygenation. But it is still lacking in the oxygenation effect and the change of dissolved oxygen concentration after entering the soil. In this study, a series of indoor simulation experiments were carried out to clarify the effect of micro-nano oxygenated water addition on the dissolved oxygen dissipation in soil. Three kinds of oxygen concentration gradient water [CK: Tap water (8-9 mg/L), O1:15 mg/L, O2:20 mg/L] were prepared to supersaturate the soil moisture in the air-dried and pre-cultivated soil using the micro-nano oxygenation. The oxygen micro-electrode was used to monitor the changes in dissolved oxygen concentration in the soil in real-time. The experiment was also performed on the treatments with the glucose and ammonium sulfate as the carbon and nitrogen substrates in the irrigation water under the different dissolved oxygen content. The variation soil dissolved oxygen dissipation was then determined in each treatment. The results show that: 1) A two-stage law was found in the rapid decline stage, followed by the slow decline stage, according to the increase of soil dissolved oxygen concentration with time. The dissipation of soil-dissolved oxygen was dominated by gas diffusion in the rapid decline stage. The dissipation curve conformed to a logarithmic function. In the slow decline stage, the consumption of soil-dissolved oxygen was mainly microbial consumption, where the dissipation curve conformed to the Logistic or linear function. 2) In the rapid decline stage of the air-dried soil test, the higher the oxygen concentration was, the longer the high oxygen state in the soil was maintained, and the higher the dissolved oxygen consumption rate was, compared with the conventional water treatment. The retention time of dissolved oxygen in the O1 and O2 treatment was prolonged by 40.11%, and 189.62%, respectively, while, the maximum consumption rate of dissolved oxygen increased by 301.53%, and 545.8%, respectively. The rapid decline stage of the pre-cultured soil test also showed a similar law to the air-dried soil test. Compared with the conventional water treatment, the dissolved oxygen dissipation time of O1 and O2 treatment was prolonged by 445.16%, and 2 741.94%, respectively, whereas, the maximum consumption rate of dissolved oxygen increased by 643.78%.and 404.32%, respectively; 3) In the slow decline stage of the air-dried soil test, the maximum consumption rates of O1 and O2 increased by 80%, and 75%, respectively, compared with the conventional. In the slow decline stage of the pre-cultured soil experiment, the overall consumption rate of dissolved oxygen in the pre-cultured soil increased by 3-4 times, compared with the air-dried soil. It infers that the consumption time was shortened several times accordingly. The treatments of CK, O1, and O2 were all carried out the oxygen consumption at a constant rate of about 0.06 mg/(L·min-1). 4) On the whole, the substrate was the key limiting factor of dissolved oxygen consumption. Specifically, the dissolved oxygen consumption rate increased by 2-3 times, whereas the dissipation time shortened by 2-3 times. In summary, there was a rapid and then slow decline stage in the change of soil dissolved oxygen content with time after the application of micro-nano oxygenated water. An overall downward trend with first fast and then slow can be expected to effectively enhance the oxygen concentration in the soil for a long period of time. The existence time of available oxygen in the soil can provide a better oxygen environment in the crop roots and soil microorganisms. Keywords: soils; [ABSTRACT FROM AUTHOR]

In view of the great difficulty of simulating the shale gas seepage process, fractal theory is applied to describe the microstructure of shale gas reservoir. Based on the multi-layer adsorption phenomenon of adsorption layer, the pressure sensitive effect and the real gas effect are taken into account, the mass flow expression of micronano shale gas is derived, and the micro-nano fractal apparent permeability model of shale gas is also established. The accuracy of the model is verified by comparing the numerical simulation with the actual production data of Well A1 in Zhaotong shale gas field. The result shows that the number of adsorbed gas layers on the pore surface is more sensitive to pressure change, but less sensitive to temperature change. Due to the pressure sensitive effect, as the diffusion resistance of shale gas increases, the apparent permeability decreases. With the increase of gas compression factor, the thickness of the adsorption layer increases and the section area ratio of the adsorption zone increases. Moreover, the pressure sensitive effect of the shale pore decreases the pore diameter, and the induced flow of the adsorbed gas decreases first and then tends to be gentle, thus reducing the overall apparent permeability of shale gas. The research results can provide part of the theoretical basis for the numerical simulation of shale gas and improve the recovery efficiency of shale gas fracturing by controlling the main control elements that affect the fractal permeability of shale gas. [ABSTRACT FROM AUTHOR]

Transition metal selenides have received great attention as promising anode materials for sodium-ion batteries (SIBs). However, it still faces the change of volume and structure, which reduces the rate performance and cycle stability in cycle process. The design of micro-nano hierarchical structure is an important method to improve the structural stability and reaction kinetics in discharge-charge process. In this study, the micro-nano Cu 2 Se is synthesized using a simple solvothermal and annealing treatment method, and it shows excellent electrochemical performance as anode material for SIBs. It exhibits excellent rate capacity (373.8 mAh g−1 at 0.1 A g−1 and 303.48 mAh g−1 when the current density is increased to 10 A g−1) and cycling stability (250.3 mAh g−1 after 4000 cycles at 5 A g−1, achieving 85.80% for retention rate). In addition, the deep reaction mechanism of Cu 2 Se has been explored through ex situ XRD and HRTEM. Micro-nano Cu 2 Se for sodium-ion battery anode with ultra-long cycle life. [Display omitted] • The micro-nano Cu 2 Se is synthesized by a simple solvothermal and annealing treatment method. • The micro-nano structure promotes electrochemical reaction kinetics. • Sodium ion battery with micro-nano Cu 2 Se delivers high-rate capability and ultralong lifespan. • The electrochemical mechanism of Cu 2 Se electrode material was revealed by ex situ XRD and HRTEM analysis. [ABSTRACT FROM AUTHOR]

As a typical microscopic imaging technology, the emergence of the microscope has accelerated the pace of human exploration of the micro world. With the development of science and technology, microscopes have developed from the optical microscopes at the time of their invention to electron microscopes and even atomic force microscopes. The resolution has steadily improved, allowing humans to expand the field of research from the initial animal and plant tissues to microorganisms such as bacteria, and even down to the nanolevel. The microscope is now widely used in life science, material science, geological research, and other fields. It can be said that the development of microscopes also promotes the development of micro- and nanotechnology. It is foreseeable that microscopes will play a significant part in the exploration of the microworld for a long time to come. The development of microscope technology is the focus of this study, which summarized the properties of numerous microscopes and discussed their applications in micro and nanotechnology. At the same time, the application of microscopic imaging technology in micro- and nanofields was investigated based on the properties of various microscopes.

To solve the problems of high cost of Cu nanoparticles (NPs) and high bonding temperature of Cu microparticles (MPs), a Cu2O NP-coated hierarchical structure (Cu-MP@Cu2O-NP) was proposed and fabricated for low-temperature Cu–Cu bonding. The Cu-MP@Cu-NP particles were obtained by Cu MPs through preoxidation and in situ reduction process, which formed a Cu particle with micro–nano core–shell hierarchical structure. The effect of preoxidation temperature on morphological features of Cu-MP@Cu2O-NP particles and mechanical properties of bonded joints were investigated. After reduction process, the generated Cu2O NPs on the surface of the hierarchical structure were reduced to Cu NPs completely. The surface NPs significantly enhanced the sinterability and structure density. After sintering at 300 °C, the shear strength of the bonded joints improved to 23.7 MPa, which is higher than that of Cu MPs without hierarchical structure. A sintering mechanism of Cu-MP@Cu-NP particles was proposed, revealing the surface NP layer is the key factor in this bonding process. [ABSTRACT FROM AUTHOR]

Abstract Porosity is the most common form of reservoirs, and its size, shape, and connectivity directly affect the capacity of oil and gas storage and production. To study the micro–nano-pore structure characteristics of shale oil reservoirs and quantitatively characterize its heterogeneity, this work uses high-precision high-pressure mercury intrusion (HPMI) experimental techniques to study the micro–nano-pore structure characteristics of shale oil, and based on the experimental data, fractal theory is used to quantitatively characterize its heterogeneity. The results of the study show that the micro–nano-pores in the shale oil reservoir are concentrated and continuous, and the pore radius is mainly distributed among the range of 30–500 nm, nanoscale pores are an important part of the pores of the shale oil reservoir. The fractal dimension of the shale oil reservoir is larger than the fractal dimension of typical tight oil reservoirs, indicating that the heterogeneity of shale oil reservoir is stronger. The research results have some theoretical and practical significance for the production of inter-salt shale oil reservoirs.

Objective: To investigate the effect of osseointegration of kaempferol loaded on the surface of micro-nanomorphic implants in ovariectomized rats.Methods: Titanium flakes were polished to obtain the PT group, anodized and acid-etched to obtain the NT and WNT groups, loaded with kaempferol to obtain the KNT and KWNT groups, and spin-coated on chitosan-gelatin composite film to obtain the KNT-CG and KWNT-CG groups. In vitro experiments were performed to observe the physicochemical properties of the titanium tablets in each group through scanning electron microscopy and contact angle experiments. The cytotoxicity and drug release pattern were observed using CCK-8 and drug release assays. An osteoporosis rat model was established. Pure titanium implants were divided into PT, NT, WNT, KNT-CG, and KWNT-CG groups after the same treatment and used in the in vivo experiments and then implanted in the femur of mice in each group. After 4 weeks, all samples were collected for toluidine blue staining, micro-computed tomography scanning, and bone morphometry analysis to evaluate their osteogenic properties.Results: According to scanning electron microscopy, the surface of the titanium flakes had a micro-nano morphology in the WNT group and the KNT and KWNT groups were functionally loaded with kaempferol. In CCK-8 and drug release experiments, the loaded kaempferol and gelatin composite membranes showed no significant toxic effects on cells. The drug release time in the KNT-CG and KWNT-CG groups was significantly longer than that in the KNT and KWNT groups, with the release time in the KWNT-CG group reaching 15 days. In vivo experiments micro-computed tomography and bone morphometry analysis showed that the osteoporosis model had been successfully constructed. The bone volume fraction around the implant increased. Toluidine blue staining showed new bone formation and a significantly increased number of bone trabeculae.Conclusion: Kaempferol micro-nanocomposite coating improved the osseointegration ability of implants in osteoporotic rats.

Porosity is the most common form of reservoirs, and its size, shape, and connectivity directly affect the capacity of oil and gas storage and production. To study the micro–nano-pore structure characteristics of shale oil reservoirs and quantitatively characterize its heterogeneity, this work uses high-precision high-pressure mercury intrusion (HPMI) experimental techniques to study the micro–nano-pore structure characteristics of shale oil, and based on the experimental data, fractal theory is used to quantitatively characterize its heterogeneity. The results of the study show that the micro–nano-pores in the shale oil reservoir are concentrated and continuous, and the pore radius is mainly distributed among the range of 30–500 nm, nanoscale pores are an important part of the pores of the shale oil reservoir. The fractal dimension of the shale oil reservoir is larger than the fractal dimension of typical tight oil reservoirs, indicating that the heterogeneity of shale oil reservoir is stronger. The research results have some theoretical and practical significance for the production of inter-salt shale oil reservoirs. [ABSTRACT FROM AUTHOR]

Copyright of Acta Materiae Compositae Sinica is the property of Acta Materiea Compositae Sinica Editorial Department and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

Micro-nano sized antibacterial copper powder was synthesized by liquid phase reduction method using copperoxide precursor．SEM, TEM and LPA test results showed that the prepared copper powder exhibit near spherical with the average size of 650nm．The antibacterial test results showed that the antibacterial rate of the micro-nano antibacterial copper powder to Escherichia coli and Staphylococcus aureus was more than９９％．Then the micro-nano antibacterial copper powder was applied to the surface coating of metal filing cabinet as antibacterial agent．The test results of antibacterial and anti-mildew showed that the antibacterial rate of the coating to Escherichia coli and Staphylococcus aureus was more than９９.９９％ and９４．４６％ respectively, and the anti-mildew grade was grade1． [ABSTRACT FROM AUTHOR]

Using the optical feedback interferometry (OFI) technique, we demonstrated a miniaturized and compact sensor system based on a dedicated optical source for flowmetry at the micro-scale. In the system, polymer microlenses were integrated directly on a VCSEL (vertical-cavity surface-emitting laser) chip and the microfluidic channel chip surface using polymer-based micro-fabrication technologies. In particular, at a post-process stage, we integrated a collimation lens on a VCSEL chip of small dimensions (200 µm × 200 µm × 150 µm). This process was enabled by the soft-printing of dry thick resist films and through direct laser writing technology. We performed flow rate measurements using this new compact system, with a conventional bulk glass lens configuration for system performance evaluation. A maximum 33 dB signal-to-noise ratio was achieved from this novel ultra-compact system. To our knowledge, this is the highest signal level achieved by existing OFI based flowmetry sensors. [ABSTRACT FROM AUTHOR]

Abstract In this paper, superhydrophobic cuprous oxide films are fabricated together etching with calcination on copper surface with an easy-to-operate and inexpensive method followed by stearic acid modification. The surface of copper wettability, surface morphology and chemical composition are characterized by contact angle measurement, scanning electron microscope, X-ray spectroscopy, Fourier Transform Infrared Spectrometry and XPS. In the light of the result, it demonstrates that micro-nanocuprous oxide structures can be achieved after etching-heat combination treatment, and by modification， hydrophobic groups including -CH 3 and -CH 2 - are introduced into the cuprous oxide particles. After contact angle measurement, the CA of surface is as high as 154.5°. What's more, when the pH is 4–8, the contact angle can still reach 120° or more. Electrochemical measurements shed light on that the superhydrophobic surface fabricated greatly improved the anti-corrosion performance of copper in 3.5 wt% NaCl aqueous solution. And the superhydrophobic surface with dual composite micro-nano structures can indicate the better corrosion resistance than that of single micro-nano structures. The presented method can be of major value for the industrial fabrication to construct inhibitive superhydrophobic surfaces of copper. This work provides a novel eco-friendly approach for corrosion protection of copper. Highlights • Superhydrophobic cuprous oxide films are fabricated. • Micro-nanocuprous oxide structures can be achieved. • The superhydrophobic surface improved the anti-corrosion performance. [ABSTRACT FROM AUTHOR]

The wellbore instability of shale formations with micro fractures was mainly ascribed to drilling fluid invasion and pressure transmission during drilling using oil-based drilling fluids (OBDF). Nano-plugging agents or micro-plugging agents at present only match a narrow size range of nanopores or microcracks. Plugging agents with good suitability to multidimensional fractures used in OBDF are lacking. This paper synthesized micro-nano polymer microsphere dispersion (PMD) with a solid content of 30 % through inverse emulsion polymerization. PMs had good wettability for water in the oil environment. The filtration of the emulsion with 4 % PMD dropped the filtration through 0.1–3 µm filters to within 14 mL while the emulsion with 1 % CaCO 3 only plugged the filter with a pore size of 3 µm. Hydrophilic PMs with a wide size distribution have excellent suitability with multi-scale pores or cracks. PMs could reduce the filtration of OBDF after aging at 120 and 150 ℃ without significantly influencing their rheology and electrical stability. Based on Darcy's law, the HTHP mud cake permeability calculated decreased by half with the addition of PMD at 120 and 150 ℃. Moreover, the addition of PMD could decline the disc HTHP filtration by 100–50 % when the disc diameter was 5–120 µm respectively. Compared with CaCO 3 , the PMD showed superior plugging performance and self-suitability when plugging 5–120 µm discs. Micro-nano PMs could interact with organic clays through hydrogen bonds to form thinner and denser mud cakes. They could also form hydrogen bonds with the formation surface. PMs could enter, aggregate and arrange tightly at multi-scale pores or cracks owing to their wide size distribution. In addition, they formed a dense plugging layer and prevent the filtration from invading the formation. The PMD with good compatibility, suitability and plugging performance has a promising application prospect in shale oil and gas exploration. [Display omitted] [ABSTRACT FROM AUTHOR]

Wellbore instability is a challenging issue in drilling engineering, especially in shale formations. The objective of this paper is to achieve wellbore stability by changing the hydrophobicity of the shale surface and plugging the micro-nano pores through the synthesis of modified polystyrene micro-nano spheres (MPS). The MPS was characterized through Fourier transform infrared spectroscopy (FTIR), thermogravimetric analysis (TGA), particle size distribution, and transmission electron microscopy (TEM). The inhibition and plugging performance of MPS were evaluated through linear expansion, shale recovery, and plugging of polytetrafluoroethylene (PTFE) microporous membrane. To study the inhibition and plugging mechanisms of MPS, contact angle, pore size distribution, and SEM analysis were performed. The results showed that MPS was spherical with a particle size distribution of 91–712 nm and had good thermal stability. The MPS had excellent compatibility with drilling fluids and better inhibition than KCl, polyamines, and SiO 2. When using PTFE microporous filter membrane as a filtration medium, the API filtration loss volume of 3 wt% MPS aqueous solution was only 42 mL, while that of the solution without MPS was 260 mL. The pore size of the PTFE microporous membrane was decreased after plugging. The MPS adsorbed on the shale surface to form a hydrophobic layer, which could weaken the hydrophilicity of shale. The contact angle of shale slices treated with 2 wt% MPS was 108.2°. Furthermore, SEM observations indicated that MPS can improve the quality of mud cakes and plug the small pores. MPS has potential applications in improving wellbore stability. [Display omitted] [ABSTRACT FROM AUTHOR]

We have demonstrated a simple and cost-effective technique for the large-area fabrication of a superoleophobic surface using copper as a substrate. The whole process included three simple steps: First, the copper substrate was oxidized under hot alkaline conditions to fabricate flower-like copper oxide microspheres by heating at a particular temperature for an interval of time. Second, the copper-oxide-covered copper substrate was further heated in a solution of cobalt nitrate and ammonium nitrate in the presence of an ammonia solution to fabricate cobalt oxide nanostructures. We applied this second step to increase the surface roughness because it is an important criterion for improved superoleophobicity. Finally, to reduce the surface energy of the fabricated structures, the surfaces were chemically modified with perfluorooctyltrichlorosilane. Contact-angle measurements indicate that the micro–nano binary (MNB) hierarchical structures fabricated on the copper substrate became super-repellent toward a broad range of liquids with surface tension in the range of 21.5–72 mN/m. In an attempt to significantly improve the superoleophobic property of the surface, we also examined and compared the role of nanostructures in MNB hierarchical structures with only micro-fabricated surfaces. The fabricated MNB hierarchical structures also displays thermal stability and excellent long-term stability after exposure in air for more than 9 months. Our method might provide a general route toward the preparation of novel hierarchical films on metal substrates for various industrial applications. [ABSTRACT FROM AUTHOR]

The understanding of multicomponent mass transport processes is essential for modeling and optimization of many systems, such as fuel cells. The understanding of individual species behavior becomes quite significant at micro-nano scales, where average mixture models are not very accurate. Also at micro-nano scales, additional phoretic transport is present due to strong local temperature and pressure gradients, which is discussed by Chakraborty and Durst (Phys Fluids 19(8):088104-01-088104-04, ). To account for multicomponent mass transport, recently proposed mass transport model by Kerkhof and Geboers (AIChE J 51(1):79-121, ), provides a way to look into individual components. This article presents extended multicomponent mass transport equations for micro-nano scales within continuum region. The Kerkhof-Geboers theory and the modifications suggested by Chakraborty and Durst () have been combined together to form a new set of equations. An extensive order of magnitude analysis has been done on the modified equations. The application of new equations to different problem situations has also been discussed. It is shown that at very small length scales and for highly diffusive transport, the phoretic transport dominates the system, thus rendering the conventional equations erroneous. [ABSTRACT FROM AUTHOR]

Abstract: Bi2O3–TiO2 composite films were synthesized by a sol–gel method under mild condition (i.e. low temperature and ambient pressure). The as-prepared films were characterized by X-ray diffraction, scanning electron microscopy, X-ray photoelectron spectroscopy, infrared spectra and fluorescence spectra. The results showed that Bi2O3–TiO2 composite films were composed of anatase titania and Bi2O3. TiO2 particles were deposited on the surface of Bi2O3 to form uniform film. Incorporating Bi2O3 with TiO2 leads to increased surface OH group density. All Bi2O3–TiO2 composite films exhibited higher photocatalytic activity compared with pure TiO2 under solar irradiation, while the film with Bi/Ti atomic ratio of 1.25% showed the highest photocatalytic activity. Furthermore, the as-prepared films can be reused with little photocatalytic activity decreasing. Without any further treatment besides rinsing, the photocatalytic activity of Bi2O3–TiO2 (1.25%) films was still higher than 77% after six-cycle utilization. [Copyright &y& Elsevier]

Heat dissipation is necessary for the safer operation of high-power electronic devices and high-capacity batteries. Thermal meta-materials can efficiently manipulate heat flow by molding natural materials into specific structures. In this study, we construct a three-dimensional-printed meta-material structure with efficient and deterministic heat conduction through combining the 2D boron nitride (BN) with nano-diamond (DM) bridging. A research of thermal conductivity and dielectric properties exhibits that the nanosized diamond-bridged and oriented 2D boron nitride endows efficient heat transfer and maintains low dielectric loss with low filler loading. The composites loaded with 19 wt% BN platelets and 1 wt% DM have the highest thermal conductivity of 3.687 W/(m·K) in the heat flow orientation, while the thermal conductivity is only 0.632 W/(m·K) in the vertical heading of heat flow. The thermal conductive networks with thermal meta-materials based on the structural characteristics have been designed to secure critical device components from the heat source and dissipate heat flow in a definite way. The infrared images show that the temperature difference of monitoring points in different directions on the BN-oriented composite substrate is 9 °C, which realizes the protection of the heat source and key components. This study shows the latent capacity of 3D-printed structured materials for critical device component protection and heat administration applications in electronic devices and electric equipment.

Conventional copper (Cu) metal surfaces are well recognized for their bactericidal properties. However, their slow bacteria-killing potency has historically excluded them as a rapid bactericidal material. We report the development of a robust bulk superhydrophilic micro-nano hierarchical Cu structure that possesses exceptional bactericidal efficacy. It resulted in a 4.41 log 10 reduction (>99.99%) of the deadly Staphylococcus aureus (S. aureus) bacteria within 2 min vs. a 1.49 log 10 reduction (96.75%) after 240 min on common Cu surfaces. The adhered cells exhibited extensive blebbing, loss of structural integrity and leakage of vital intracellular material, demonstrating the rapid efficacy of the micro-nano Cu structure in destructing bacteria membrane integrity. The mechanism was attributed to the synergistic degradation of the cell envelope through enhanced release and therefore uptake of the cytotoxic Cu ions and the adhesion-driven mechanical strain due to its rapid ultimate superhydrophilicity (contact angle drops to 0° in 0.18 s). The scalable fabrication of this micro-nano Cu structure was enabled by integrating bespoke precursor alloy design with microstructure preconditioning for dealloying and demonstrated on 2000 mm2 Cu surfaces. This development paves the way to the practical exploitation of Cu as a low-cost antibiotic-free fast bactericidal material. [ABSTRACT FROM AUTHOR]

The achievement of superamphiphobic material with ultralow sliding angles is a highly worthwhile and challenging task because the current artificial superhydrophobicity can be easily contaminated and wetted by low surface tension liquids. Herein, we construct superamphiphobic 5083 aluminum alloy surface through a facile strategy including sono-assisted HCl etching, boiling H 2 O treatment and POTS grafting. Micro-nano dual scale hierarchical structure was achieved, attributing to air cushion formation and Cassie contacts. The as-prepared superamphiphobic HCl-H 2 O-POTS AA5083 surface has a wide range of liquids repellency to water, glycerol, ethylene glycol, peanut oil and even n-hexadecane (surface tension: 27.5 mN·m−1). The superamphiphobic surface also possesses outstanding self-cleaning ability for contaminants and chemical stability for liquid droplets with different pH values. All these advantages will endow the superamphiphobic HCl-H 2 O-POTS surface with broad applications prospects, including automobile, aerospace, military and marine industries. Self-cleaning and chemically stable superamphiphobic HCl-H 2 O-POTS AA5083 surface was developed through a facile strategy of sono-assisted HCl etching, boiling H 2 O treatment and POTS grafting. Unlabelled Image • Superamphiphobicity was achieved by HCl-etching, H 2 O-treatment and POTS grafting. • The HCl-H 2 O-POTS surface repels liquids with surface tension from 72.8 to 27.5 mN·m−1. • Outstanding chemical stability was confirmed with pH values ranging from 1 to 14. • The surface exhibits repeatability and stability after 20 times self-cleaning tests. [ABSTRACT FROM AUTHOR]

Condensation occurs in most of the heat transfer processes, ranging from cooling of electronics to heat rejection in power plants. Therefore, any improvement in condensation processes will be reflected in the minimization of global energy consumption, reduction in environmental burdens, and development of sustainable systems. The overall heat transfer coefficient of dropwise condensation (DWC) is higher by several times compared to filmwise condensation (FWC), which is the normal mode in industrial condensers. Thus, it is of utmost importance to obtain sustained DWC for better performance. Stability of DWC depends on surface hydrophobicity, surface free energy, condensate liquid surface tension, contact angle hysteresis, and droplet removal. The required properties for DWC may be achieved by micro–nanoscale surface modification. In this survey, micro–nanoscale coatings such as noble metals, ion implantation, rare earth oxides, lubricant-infused surfaces, polymers, nanostructured surfaces, carbon nanotubes, graphene, and porous coatings have been reviewed and discussed. The surface coating methods, applications, and enhancement potential have been compared with respect to the heat transfer ability, durability, and efficiency. Furthermore, limitations and prevailing challenges for condensation enhancement applications have been consolidated to provide future research guidelines. [ABSTRACT FROM AUTHOR]