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[Display omitted] • Various Pd particle sites were constructed on the catalysts through high-temperature reduction of the carriers. • With different Pd sites, HCHO oxidation mechanism changed. • Besides formate, intermediate CO species coexisted on Pd/SiO 2 (5 0 0) and Pd/SiO 2 (8 0 0) catalysts. • The intermediate formate and CO are related to active hydroxyl groups and corner sites, respectively. In general, for Pd-based catalysts, the smaller the Pd particles on the catalysts are, the better the activity for HCHO oxidation; this has solely been ascribed to the high Pd dispersion on the catalysts' surface. However, the Pd site effect on HCHO oxidation is still not clear. In this work, we regulated the proportions of different Pd sites on Pd/SiO 2 catalysts by high-temperature treatment of the carriers. With the increase in treatment temperature, the dominant active sites on Pd particles changed from terraces to steps and finally to corner sites. The corner sites were found to be important for oxygen activation, which led to the HCHO catalytic oxidation performance increasing in the order Pd/SiO 2 , Pd/SiO 2 (5 0 0) and Pd/SiO 2 (8 0 0). It is worth noting that in the reaction pathway for HCHO oxidation, formate was the primary intermediate on the Pd/SiO 2 catalyst. However, in addition to formate, CO species were also detected on the Pd/SiO 2 (5 0 0) and Pd/SiO 2 (8 0 0) catalysts. DFT results confirmed that the corner sites were more favorable for the HCHO → CHO → CO pathway, compared to the terrace sites. This work elucidates the effect of Pd sites on the HCHO oxidation mechanism over Pd/SiO 2 catalysts, providing valuable insights for the design of highly active catalysts. [ABSTRACT FROM AUTHOR]

The droplet anisotropic wetting on chemically heterogeneous stripe-patterned substrates after impact is studied by using many-body dissipative particle dynamics in this work. After a low-velocity impact on substrates with different length ratio (ratio of stripe width to the initial droplet size) and Cassie area fraction, the droplet can show various shapes and contact angles in parallel and orthogonal directions to the stripes. The elongation of the droplet can be increasingly evident when increasing the length ratio. Also, the contact angles at both directions follow the Cassie-Baxter predicted values well at low length ratio while deviate from them at high length ratio. Both the capillary and kinetic effects have a significant influence on the anisotropic wetting. When impact with higher velocity, the droplet leaves some residues on the hydrophilic stripes of the substrates. Surprisingly, the residues for substrates with certain length ratio (≤0.316) are distributed in circular regions with almost identical radii, indicating the spreading stages of them are independent on the surface properties and dominated by the kinetic effect. When the droplet reaches a stable state, the main body shows anisotropic wetting behavior, indicating the capillary effect dominates the wetting instead of the kinetic effect at the retraction stage. Unlabelled Image • Combined effect of length ratio, Cassie area fraction and initial kinetic energy is considered in spreading on substrates. • Critical length ratio is identified to separate the anisotropy and isotropy of wetting. • The droplet shows no anisotropic effect in spreading stage when given a high initial impact velocity. • A simple algorithm is proposed to calculate the contact angle of the droplet with distorted contact line. [ABSTRACT FROM AUTHOR]

[Display omitted] • Surface characteristics of spherical nanoclustered (NC)-ceria nanoparticles (NPs) with varying diameters were investigated. • NC-ceria NPs exhibited a high specific surface area and surface activity (i.e., Ce3+/Ce4+). • The smallest NC-ceria NP slurry achieved the highest SiO 2 removal rate in the chemical mechanical planarization process. The particle size of cerium oxide (ceria) abrasives plays a crucial role in the design and development of advanced self-stopping slurries for the chemical mechanical planarization (CMP) process in semiconductor device manufacturing. However, a lack of ceria nanoparticles (NPs) with a narrow size distribution and uniform shape poses challenges in investigating the fundamental principles of the relationship between abrasive size and CMP performance. In this study, we thoroughly investigated the effect of ceria NP size on the removal rate (RR) of silicon oxide using uniform-sized nanoclustered (NC) ceria NPs with three diameters: 51.4 nm (NC51), 68.6 nm (NC69), and 108.0 nm (NC108). While all three types of ceria NPs shared a crystallinity of ∼ 70.6 %, they exhibited distinct physicochemical characteristics. As the particle size decreased, the specific surface area and chemical activity (i.e., Ce3+/Ce4+) increased by 155 % and 69 %, respectively. In the CMP process, where direct contact between the abrasives and wafer occurs, the abrasive size influences CMP performance. Experimentally, NC51 achieved the highest RR among the three slurries, along with complex size-dependent contact properties and chemical activities. These experimental results offer significant insights into precise semiconductor manufacturing in a practical manner. [ABSTRACT FROM AUTHOR]

Graphical abstract Highlights • A ship-in-bottle strategy is used to fabricate yolk-shell nanocomposites. • The shell thickness is ∼15 nm and the pore size is about 4.0 nm for HCS. • Particle size of Cu in Cu@HCS can be controlled by varying the heating rate. • The catalytic performance of Cu@HCS is significantly influenced by particle size. • Cu@HCS behaves higher activity and stability than commercial CuCl catalyst. Abstract Cu nanoparticles (NPs) encapsulated within a hollow carbon spheres (Cu@HCS) is an effective catalyst with optimal structural design for the oxidative carbonylation of methanol to dimethyl carbonate (DMC). Control of the structural properties of both the shell and the core plays a vital role in determining the catalytic properties. In this study, mesoporous HCS with an average diameter of 190 nm and a shell thickness of 15 nm were obtained using silica micropheres as a hard template and by tuning the amount of resorcinol and formaldehyde. Cu@HCS catalysts were fabricated by hydrothermal impregnation followed by hydrogen reduction, and the size of Cu NPs was delicately controlled by varying heating rate of reduction process. The results show that a thin mesoporous carbon shell of Cu@HCS is beneficial to the diffusion of reactants and products, and that Cu NPs with very small size can provide a large active specific surface area. In comparison with the commercial CuCl catalyst, the Cu@HCS-5 catalyst displays superior catalytic activity; its turnover frequency and apparent activation energy reaches 23.1 h−1 and 20.5 kJ·mol−1, respectively. In addition, it exhibits higher stability than that of CuCl because the carbon shell prevents the aggregation and leaching of copper NPs during the reaction. With the advantages in catalytic activity, corrosion effect, and recovery performance, the Cu@HCS catalyst has a promising potential for realizing the cleaner production of DMC. [ABSTRACT FROM AUTHOR]

[Display omitted] • Liquid-assisted laser cleaning process is optimized for nanoscale particle removal. • Performance limit of liquid-assisted laser cleaning technology is uncovered. • More than 90% of 3-nm-sized gold particles are removed from Si surfaces. • 90% removal limit is 20 nm for polystyrene and 50 nm for alumina. • Notably high cleaning performance for gold is due to strong field enhancement. Since the development of the liquid-assisted laser cleaning method known as "steam laser cleaning (SLC)", its application in semiconductor manufacturing has been limited due to its wet nature and potential damage caused by electromagnetic-field enhancement. However, as the primary target size has now been shifted towards the sub-10-nm range, the potential of SLC needs to be reassessed in the unexplored domain. Because previous studies have been focused on particles over ∼100 nm, the process has hardly been optimized for smaller particles. Moreover, the chance of damage generation by large dielectric particles is small in the case of nanoscale particles. Consequently, this study aims to identify the smallest particle size that can be removed from a silicon surface for gold, polystyrene (PS), and alumina particles. After optimizing the process through numerical simulation and experiment, the damage threshold and the particle removal efficiency (PRE) are measured by varying the laser fluence and particle size. The lower size limit, as determined by a 90 % PRE criterion, is 3 nm for gold particles, 20 nm for PS particles, and 50 nm for alumina particles. Discussions are made on the mechanisms responsible for the relatively high cleaning performance observed for gold particles. [ABSTRACT FROM AUTHOR]

[Display omitted] • Ru/TiO 2 catalysts with 1.1 nm (small), 2.9 nm (medium) and 5.2 nm (large) Ru particles were successfully synthesized. • The medium Ru particles on TiO 2 exhibited the best CO 2 methanation activity. • The medium Ru particles exhibited the best redox properties compared with small and large Ru particles. • The medium Ru particles exhibited a moderate ability to activate CO 2 , resulting in the best CO 2 methanation activity. The influence of metal particle size over heterogeneous catalysts on the catalytic performance has always been an interesting subject due to its significance from both fundamental and practical perspectives. In this work, we regulated the synthesis of TiO 2 by the hydrolysis of different titanium precursors, and as-prepared TiO 2 supports were employed to load Ru with impregnation method. Interestingly, we synthesized three Ru-TiO 2 catalysts with different Ru particle sizes of 1.1, 2.9 and 5.2 nm. The Ru-TiO 2 catalysts were next tested for CO 2 hydrogenation reaction, the results show that the medium Ru particles on TiO 2 exhibited the best CO 2 methanation activity. Based on the characterizations, we observed that the medium Ru particles exhibited the best redox properties compared with small and large Ru particles, which was beneficial to the H 2 dissociation; in addition, the medium Ru particles exhibited a moderate ability to activate CO 2 , resulting in the most favorable formation and decomposition of bidentate bicarbonate. Consequently, the Ru-TiO 2 catalyst with medium Ru particles showed the highest activity for CO 2 methanation. This study provides a new method to prepare Ru-TiO 2 catalysts with different Ru sizes and also presents an understanding of Ru particle size effects on CO 2 hydrogenation. [ABSTRACT FROM AUTHOR]

Schematic diagram of the developed single-particle SERS sensor. [Display omitted] • A sensitive, single-particle SERS sensing platform for pathogenic bacteria quantification using hierarchical Au microparticles was reported. • Novel hierarchical Au microparticles with a size comparable to the laser spot of a Raman microscopy were synthesized for SERS substrates. • A limit of detection (LOD) as 0.93 cfu/mL and a broad detection range from 101 to 106 cfu/mL were achieved. • This method provides a promising SERS platform for detecting any other environmental hazardous materials feasibly. In this study, a sensitive and robust single-particle SERS sensing platform for profiling of Staphylococcus aureus (SA) in complex samples was developed. The hierarchical Au microparticles (HAMs) with intense surface-enhanced Raman scattering (SERS) enhancement were synthesized. These HAMs were capable of capturing SA by modifying them with specific SA -targeting aptamers. The captured SA was then selectively bound to aptamer-modified spherical Au nanoparticles (AuNPs), resulting in a sandwiched structure of HAMs-bacteria-AuNPs. This structure led to enhanced SERS signals, enabling the quantitative detection of SA. We achieved a broad and linear range of SA detection from 1 × 101 to 1 × 106 cfu/mL, with a limit of detection (LOD) of 0.93 cfu/mL. Furthermore, we successfully measured the presence of SA in milk samples, obtaining a recovery rate from 98.2% to 101.1%. These results demonstrate the potential application of the developed method in food safety, infectious diseases, and other health-related safety supervision. [ABSTRACT FROM AUTHOR]

A series of supported CoCr 2 O 4 /TUD-1 catalysts with different loadings were prepared and tested for catalytic combustion of dichloromethane, in order to investigate the effect of particle size on the catalyst properties and related catalytic behaviors. It was found that the supported catalyst with low content of CoCr 2 O 4 had smaller CoCr 2 O 4 particles compared to that with high content, as revealed by the XRD results. Consequently, the changes in particle size altered the surface composition of the catalyst, as the small particles contained higher content of surface Cr 6+ species compared to the large ones. The enrichment of Cr 6+ species improved catalyst reducibility and surface acidity, which synergistically governed the observed catalytic behaviors. As a reuslt, the 5CoCr 2 O 4 /TUD-1 catalyst had the highest reaction rate of 64.8 × 10 −7 molDCM g −1 CoCr2o4s −1 , due to its best reducibility and highest surface acidity. [ABSTRACT FROM AUTHOR]

Single femtosecond laser pulses are employed to ablate an aluminium target in vacuum, and the particle size distribution of the ablated material deposited on a mica substrate is examined with atomic force microscopy (AFM). The recorded AFM images show that these particles have a mean radius of several tens of nanometres. It is also determined that the mean radius of these deposited nanoparticles increases when the laser fluence at the aluminium target increases from 0.44 J/cm 2 to 0.63 J/cm 2 . The mechanism of the laser-induced nanoparticle generation is thought to be photomechanical tensile stress relaxation. Raman spectroscopy measurements confirm that the nanoparticles thus produced have the same structure as the bulk aluminium. [ABSTRACT FROM AUTHOR]

Abstract With the aim of application as either a conductive filler or a sinter-bonding material with enhanced antioxidation properties, Ag-coated Cu (Cu@Ag) particles with thick Ag shells were fabricated and heated at 220 °C for 10 min in air to observe the dewetting behavior of the thick Ag shell. The fabricated Cu@Ag particles were spherical with the average size of 2 μm, and the Ag shell was 250–400 nm in thickness, comprising a mixed Ag-Cu layer and a dense Ag layer. As the heat-treatment time increased, the Cu@Ag particles were aggregated by forming numerous Ag nodules covering the surface of the particle. Dewetting in the thick Ag shell occurred from 4 min and only in the outer layer of the Ag shell even after 10 min of heat-treatment. In addition, the thickness of the dewetting layer and the mixed Ag-Cu layer were increased because the outward diffusion of Cu and Ag were increased proportionally with the time. However, because the dense Ag layer remained even after the dewetting of the Ag shell and the formation of the mixed Ag-Cu layer, the Cu@Ag particles were not oxidized after heating at 220 °C for 10 min in air. Highlights • Ag-coated Cu particles with thick Ag shells were fabricated and heated at 220 °C in air. • Thickness of dewetting layer, dense Ag layer, and mixed Ag-Cu layer changed during heating. • Ag-coated Cu particles became highly sintered by forming a dewetting layer in the outer shell. • Diffusion of Cu and Ag was accelerated by the instability of the Cu/Ag interface. • The dense Ag remained even after the heating, which improved anti-oxidation properties. [ABSTRACT FROM AUTHOR]

Convective heat transfer studies on aqua-antifreeze based magnesia (MgO) nanofluids with 0.05, 0.2 and 0.6% particle concentrations (ϕ) were carried out by the use of a twisted tape equipped circular tube. To investigate the particle shape effects over the heat transfer and entropy generation, the synthesized nanoflakes and the purchased spherical nanoparticles of nearly similar sizes were chosen. Characterization studies were carried to confirm the particle size, structure, composition, bonding nature and stability of the nanofluids. Based on the DLVO theory, nanofluid stability of ϕ = 0.05 and 0.2% were better. The zeta potential results confirm that the nanofluids are stable around pH 6 and 12. The higher surface tension of the nanoflake based fluid indicates the presence of stronger van der Waals forces leading to a quicker agglomeration. Based on the heat transfer and friction factor enhancement, the highest Performance Evaluation Factor (PEF) of 1.88 and 1.74 were achieved by nanoflakes and nanoparticles, respectively. On the basis of Entropy Performance Evaluation Factor (EPEF), the use of nanoflakes beyond the Reynolds number of 7200 is unadvisable due to its higher frictional entropy generation and hence the best choice for nanofluids is the spherical nanoparticles for optimized and efficient use. Unlabelled Image • Study on two particle shapes of Magnesia nanopowder – nanoflakes and nanoparticles • As per the DLVO theory, 0.2% particle concentrated nanofluids were the most stable. • Performance Evaluation Factor estimates nanoflakes as an efficient choice for nanofluid. • The optimized limit for nanoflake based nanofluid is at Reynolds number of 7200. • Nanoparticles are the optimal choice for nanofluids with no limits in Reynolds number. [ABSTRACT FROM AUTHOR]

[Display omitted] • Metal particle size effects over the bifunctional Ni/SAPO-11 hydroisomerization catalysts were investigated. • Decreasing Ni particle size significantly increases the concentration of surface Ni atoms and the proportion of low-coordinated Ni sites (corner, step sites), resulting in a significantly enhanced ability in adsorption and activation of the reactants. • The higher intrinsic catalytic activity of smaller Ni particle for n-hexane hydroisomerization is due to the higher proportion of low-coordinated Ni sites. • The smaller Ni particle enhance the metal–acid synergy and prevent the intermediate from undergoing excessive acid-catalyzed steps, leading to a higher selectivity to isomers. The prominent size effects of metal nanoparticles (NPs) are mainly reflected in the change of electronic and geometric properties, which may induce distinct catalytic performance of the catalyst. Herein, Ni/SAPO-11 bifunctional catalysts with controllable sizes of Ni NPs were synthesized to investigate the particle size effects in n-hexane hydroisomerization. The results show that decreasing Ni particle size from 11.7 to 5.3 nm increases the concentration of surface Ni atoms and the proportion of low-coordinated Ni sites (corner, step sites) by 1.7 and 1.5 times, respectively. The low-coordinated surface Ni atoms have rich dangling bonds and high surface energy, resulting in greatly improved H 2 adsorption and activation abilities. Moreover, an increased proportion of low-coordinated Ni sites within the Ni cluster shifts the d-band center upward, further enhancing the adsorption and activation of reactants. The intrinsic catalytic activity (turnover frequency) of 5.3 nm Ni NPs is ca. 2 times as much as that of the 11.7 nm ones. Besides, the smaller Ni NPs enhanced the metal–acid synergy, leading to a higher selectivity to isomers. This work provides deep insights into the metal particle size effects over the bifunctional Ni/SAPO-11 hydroisomerization catalysts and can be extended to various metal supported catalysts. [ABSTRACT FROM AUTHOR]

The study of the effect of particle size and low coordination sites in metal nanoparticles (Cu n , Ag n and Au n with n = 19, 38, 55, 79 and 116) on the reduction of NO 2 to NO + O, was carried out using density functional theory (DFT) calculations. All metal nanoparticles have shown to be more favorable for the NO 2 adsorption than the (111) extended surfaces. The adsorption energy order of NO 2 found for both configurations, O-down (most stable) and N-down, was Cu > Ag > Au. The dissociation energy values of NO 2 on Cu and Ag nanoparticles decrease with the increment of the particle size, however, considering the activation barrier values, the most reactive substrates evaluated were Cu(111) surface, and the Cu 19, Cu 116. The activation barriers (E act) for the larger nanoparticles, were obtained using a non-traditional relationship of Brönsted Evans Polanyi (BEP), from the E act calculated on the smaller ones. The BEP relations highly depend on the reaction product configurations and also on the structure of the active site. Notwithstanding that the nanoparticles improve the NO 2 adsorption and the dissociation energies are lower than those corresponding to the extended surfaces, the activation barriers are higher. Unlabelled Image • NO 2 is preferably adsorbed with O-down configuration on Cu, Ag and Au substrates. • Increase in Cu and Ag particle sizes leads to a decrease in NO 2 dissociation energy. • Activation barriers of largest nanoparticles were obtained using a non-traditional BEP relationship. • Low coordination sites in nanoparticles improve NO 2 adsorption but not its dissociation. [ABSTRACT FROM AUTHOR]

[Display omitted] • We fabricated α-particle Schottky barrier detectors based on a high-quality 4H-SiC epitaxial layer. • The detectors were tested at temperatures up to 500 °C. • Their reverse current rose from 1 pA at room temperature to 10 nA at 500 °C. • Their energy resolution worsened only by 20% compared with that at room temperature. Industry demand for radiation detectors that work at elevated temperatures is currently growing. Detectors capable of operating at high temperatures are used in harsh environments, such as the nuclear industry, especially thermonuclear or fusion reactors, high-energy physics experiments and space research. We prepared detectors based on a high-quality 50 μm thick 4H-SiC epitaxial layer. The 4H-SiC detector area was defined by an Ni Schottky contact with a diameter of 1 mm. The current–voltage characteristics of the detector measured at room temperature (RT) showed a leakage current of 1 pA at 300 V. The measurement was done at elevated temperatures up to 500 °C, and the leakage current increased to 10 nA. Precise temperature stabilization was achieved using a low-noise self-controlled microcontroller system with a PID loop using ceramic heaters in a customized vacuum chamber. The spectrometric performance of the detector was tested using α-particles generated by 238Pu, 239Pu, 244Cm radioisotopes. The energy resolution of the tested α-particle peaks was about 35 keV at full width at half maximum (FWHM) at RT and increased to 42 keV at a detector temperature of 500 °C. We also observed that the mean energy for the generation of one electron-hole pair changed with temperature. In this article, we push the limits and report on very promising experimental results about a 4H-SiC wide bandgap semiconductor detector operating at very high temperatures. [ABSTRACT FROM AUTHOR]

The influence of the hard particle on the surface generation, plastic deformation and processing forces in nano-cutting of aluminum is investigated by means of molecular dynamics simulations. In this investigation, a hard particle which is simplified as a diamond ball is embedded under the free surface of workpiece with different depths. The influence of the position of the hard ball on the surface generation and other material removal mechanism, such as the movement of the ball under the action of cutting tool edge, is revealed. The results show that when the hard particle is removed, only a small shallow pit is left on the machined surface. Otherwise, it is pressed down to the subsurface of the workpiece left larger and deeper pit on the generated surface. Besides that, the hard particle in the workpiece would increase the processing force when the cutting tool edge or the plastic carriers interact with the hard particle. It is helpful to optimize the cutting parameters and material properties for obtaining better surface quality in nano-cutting of composites or other materials with micro/nanoscale hard particles in it. [ABSTRACT FROM AUTHOR]

[Display omitted] • Amorphous coatings riching in ITO-CNTs were fabricated by one step PEO method with nanoparticles addition. • The formation mechanism of amorphous phase was proposed. • CNTs additive and the amorphous coating synergistically improved the tribological performance of aluminum alloy. As moving machine parts, aluminum alloys suffer from poor wear resistance, however, the combination of amorphous materials and anti-friction lubricant phases has rarely been investigated to improve tribological performance. The amorphous coatings were fabricated by one-step plasma electrolytic oxidation (PEO) with ITO and CNTs addition, of which CNTs were used as lubricant additives to enhance the anti-friction properties of aluminum alloy. It is found that the amorphous phases in the coatings increase with ITO concentration in the electrolyte. As well as, when the concentration of ITO in the electrolyte reaches 40 g/L, XRD cannot detect Al 2 O 3 phase, but only ITO and amorphous phase. The formation of the amorphous coating is due to the fact that In3+ can be used as a network modifier to improve the glass-forming ability of molten oxides and the rapid cooling after discharge. Further, the amorphous coating exhibits a higher hardness (1472 HV 0.5) compared to single Al 2 O 3 coatings (267 HV 0.5) and its main wear mechanism is adhesive wear with a high friction coefficient (∼0.68). In contrast, with the incorporation of CNTs, the amorphous coating exhibits slight abrasive wear after 6000 sliding cycles under dry friction conditions, with a stable frictional coefficient of around 0.14. Of which, the amorphous coating (1704 HV 0.5) serves as a load-bearing and CNT acts as a lubricant phase during friction and wear. Hence, through the synergistic effect of the CNTs additive and the amorphous coating, the tribological properties of aluminum alloy are significantly improved, with a low friction coefficient and shallow wear trace. [ABSTRACT FROM AUTHOR]

Ethylenediamine (EDA) was added to modified Pt/SiAl catalyst by co-impregnation method for selective catalytic oxidation of ammonia (NH 3 -SCO), which for the purpose of optimizing the low-temperature ammonia oxidation activity of Pt/SiAl catalyst. The results of several characterizations indicated that the addition of EDA could adjust the states and particle sizes of Pt, and the reduction property of Pt/SiAl catalyst, which together contributed to with the catalytic performance of catalysts and could be confirmed by XRD, TEM, H 2 -TPR and CO-FTIR. Detailed, the result of H 2 -TPR revealed more excellent reduction property of Pt/SiAl-E and the CO-adsorption result displayed more electron-rich of Pt species and more Pt0 species over Pt/SiAl-E than Pt/SiAl. The TEM results demonstrated the average particle sizes of Pt species decreased from 2.8 nm to 2.0 nm after adding EDA. Consequently, Pt/SiAl-E displayed better low-temperature NH 3 -SCO activity than Pt/SiAl, the light-off temperature of ammonia dropped from 217 °C to 205 °C. Unlabelled Image • Higher dispersion of active species Pt0 was obtained by a salt of Pt-chelated with EDA to inhibit the sintering of Pt0. • Light-off temperature of ammonia was dropped from 217 °C to 205 °C after adding EDA into Pt/SiAl. • Pt0 was the active species of ammonia oxidation reaction in the low temperature. [ABSTRACT FROM AUTHOR]

Metal oxide semiconductors are widely used as gas sensing materials; thus, improving their gas sensing properties is of some interest. The microstructure of a SnO 2 film was controlled using the thermal evaporation technique at a relatively high process pressure. Scanning electron microscopy (SEM), X-ray diffraction (XRD), transmission electron microscopy (TEM), and Brunauer-Emmett-Teller (BET) analysis were used to characterize microstructures, crystallinity, particle size, and the surface area that was dramatically altered as a function of the process pressure. In all cases, SnO 2 films had interconnected network structures with open pores; continuous grain growth was observed through the neck between the SnO 2 nanoparticles. The responses of sensors fabricated at different depositional pressure were evaluated by monitoring changes in the electrical resistance of CO gas. The gas sensor deposited at 0.2 Torr showed a high response and short response time owing to its high porosity (97%) and nano-sized particles (8.4 nm). The results confirm that porosity and particle size play key roles in determining the gas response. Unlabelled Image • Various SnO 2 films were prepared by thermal evaporation at high pressure. • SnO 2 films had an interconnected network structure between nanoparticles. • SnO 2 films had open pores and porosity of over 70%. • Nanoporous SnO 2 films exhibited a high gas response and a short response time. • Porosity and particle size play a key role in determining the gas response. [ABSTRACT FROM AUTHOR]

[Display omitted] • Nanocrystals were introduced into the surface layer after SFPB. • Wear resistance of the treated samples was improved. • The mechanism of SFPB on the wear properties of 304 stainless steel was provided. The effects of supersonic fine particle bombardment (SFPB) on the wear properties and surface integrity of 304 stainless steel were investigated. Moreover, the impact of different air pressures (1, 1.5, and 2 MPa) on the microstructure, microhardness, and tribological behaviour of the material was explored. The results indicated that SFPB significantly refined the surface grains and transformed the austenitic phase into the martensite phase. The subsurface microhardness of 304 stainless steel increased with air pressure, with maximum increases of 58%, 90%, and 98% at 1, 1.5, and 2 MPa, respectively. However, higher air pressures resulted in increased microdefects, which adversely affected the wear rates. Notably, the sample with the highest microhardness (2 MPa) exhibited the highest wear rate, whereas the best tribological performance was observed at 1.5 MPa. Surface integrity analysis revealed that the tribological performance of 304 stainless steel was influenced by both surface defects and surface nanocrystals. This study provides insights into the mechanism by which SFPB affects the wear properties of 304 stainless steel. [ABSTRACT FROM AUTHOR]

This work deals with the properties of secondary particles, i.e., sputtered target and scattered primary particles, for the ion beam sputtering of TiO 2 in a reactive oxygen atmosphere. The angular and energy distributions in dependence on ion beam parameters (ion energy, ion species, or ion mass) and geometrical parameters (ion incidence angle, polar emission angle, or scattering angle) were investigated. The angular distributions of sputtered Ti particles were determined by the collection method, i.e., by growing TiO 2 thin films and measuring the thickness, composition, and mass density. The distributions can be described by the superposition of an isotropic and an anisotropic part. The anisotropic part relative to the isotropic part gets more pronounced with decreasing ion energy, increasing ion incidence angle or changing the process gas from Ar to Xe. An energy-selective mass spectrometer was used to measure mass and energy distributions of secondary ions. The most prevalent species were identified to be O+, O 2 +, Ti+, TiO+, Ar+, and Xe+ ions. The energy distributions of Ti+ and TiO+ ions show a low-energy maximum between 10 eV and 30 eV, followed by an exponential decay. When decreasing the scattering angle, the high-energy tail extends to higher energies. O+, O 2 +, Ar+, and Xe+ ions show a low-energy maximum between 5 eV and 20 eV, which is followed by a sudden signal drop for scattering angles larger than 90°. For scattering angles smaller than 90°, additional peak(s) at higher energy appear, which are assigned to direct scattering and/or direct sputtering events. The experimental results are compared to calculations based on elastic collision theory and to simulations done with the Monte Carlo code SDTrimSP. The results are also discussed in relation to secondary particle properties for the reactive ion beam sputtering of Ti and to properties of TiO 2 thin films grown by reactive ion beam sputter deposition with the same setup and the same parameters. Among others, it was found that sputtering of the TiO 2 target exhibits less anisotropy contributions than sputtering of the Ti target. • Low-energy ion beam sputtering of TiO 2 in oxygen atmosphere • Angular distributions of sputtered Ti particles consist of isotropic and anisotropic part. • Most prevalent secondary ion species O+, O 2 +, Ti+, TiO+, Ar+ or Xe+ • Anisotropy effects results in high-energy secondary ions. • Correlation with properties of TiO 2 films grown by ion beam sputter deposition [ABSTRACT FROM AUTHOR]

Highlights • Electron injection and transport properties of mesoporous layer containing TiO 2 nanoparticles are investigated. • The photovoltaic properties are poor with small TiO 2 particles and thick mesoporous layers. • This poor performance is due to the increase of the area of the TiO 2 /TiO 2 interface. • The TiO 2 /TiO 2 interfacial resistance largely influences the photovoltaic parameters. Abstract Mesoporous TiO 2 (mp-TiO 2) layers are commonly used as electron transport layers in perovskite solar cells, which help to extract electrons from the perovskite light-absorbing layer and transport them to the electrodes. We investigated the effects of the layer thickness of mp-TiO 2 and particle size of TiO 2 on photovoltaic properties, in terms of the surface area of the mp-layer and the interfacial areas of the TiO 2 nanoparticles in the mp-layer. Various mp-TiO 2 layers with thicknesses of 150, 250, and 400 nm and particle sizes of 25 nm and 41 nm were prepared to compare the photovoltaic properties of such layer-containing perovskite solar cells. Time-resolved photoluminescence decay and impedance studies showed that interfacial resistance as well as perovskite-to-TiO 2 charge injection are important factors affecting photovoltaic performance. The deterioration of the photovoltaic parameters with increasing TiO 2 /TiO 2 interfacial area also confirms that the interfacial series resistance that arises from these connections should be reduced to enhance the performance of mesoscopic perovskite solar cells. [ABSTRACT FROM AUTHOR]

Graphical abstract Highlights • Combination of QCM-D and in-situ reflection FTIR spectroscopy. • Comparison of water adsorption on smooth films and particle layers. • Distinction of water adsorption on surfaces and contact points of particle layers. • Monomolecular surface functionalization of SiO 2 -particle layers by perfluorinated molecules. Abstract Monodisperse micron-sized silica particle monolayers deposited onto plasma-grown SiO x -ultra-thin films have been used as reference systems to investigate wetting, water adsorption and capillary bridge formation as a function of silica surface functionalization. 1H,1H, 2H,2H perfluorooctyltriethoxysil (FOTS) monolayers, have been deposited on the respective surfaces by means of chemical vapor deposition resulting in macroscopically low energy surfaces. X-ray photoelectron spectroscopy (XPS) and Fourier transform infrared (FTIR) reflection absorption spectroscopy confirmed the monolayer formation. Water adsorption isotherms were studied by a combination of in-situ FTIR reflection spectroscopy and quartz crystal microbalance (QCM) while macroscopic wetting was analysed by contact angle measurements. The comparative data evaluation indicates that the macroscopic wetting behaviour was changed as expected, however, that water nanodroplets formed both at intrinsic defects of the FOTS monolayer and at the FOTS/SiO x interface. Capillary bridges of liquid water are dominantly formed in the confined particle contact areas and between surface asperities on the particles. The comparison of wetting, adsorption and capillary bridge formation shows that the hydrophobization of porous materials by organosilane monolayers leads to the formation of morphology dependent nanoscopic defects that act as sites for preferential capillary bridge formation. [ABSTRACT FROM AUTHOR]

In this research, topographic, optical and chemical properties of zinc oxide layers deposited by a cold plasma-spray process were measured. Here, zinc micro particles were fed to the afterglow of a plasma spark discharge whereas the substrates were placed in a quite cold zone of the effluent plasma jet. In this vein, almost closed layers were realised on different samples. As ascertained by laser scanning and atomic force microscopic measurements the particle size of the basic layer is in the nanometre scale. Additionally, larger particles and agglomerates were found on its top. The results indicate a partial plasma-induced diminishment of the initial particles, most probably due to melting or vaporisation. It is further shown that the plasma gives rise to an increased oxidation of such particles as confirmed by X-ray photoelectron spectroscopy. Quantitative analysis of the resulting mixed layer was performed. It is shown that the deposited layers consist of zinc oxide and elemental zinc in approximately equal shares. In addition, the layer's band gap energy was determined by spectroscopic analysis. Here, considerable UV blocking properties of the deposited layers were observed. Possible underlying effects as well as potential applications are presented. [ABSTRACT FROM AUTHOR]

Inorganic/organic hybrid layers have been prepared having superhydrophobic as well as photoreactive properties. The hybrid thin films with micro- and nanosized dual-scale surface roughness consist of ∼25 μm layered double oxide (LDO) photocatalyst particles and low surface energy poly(perfluorodecyl acrylate) [p(PFDAc)] fluoropolymer binder material. The application of [p(PFDAc)] resulted in the decrease in the surface free energy of the hydrophilic LDO. The structured surface LDO with ∼12% ZnO phase content were synthesized from layer double hydroxide (LDH) spheres. The determined excitation wavelength and the calculated band gap energy values were 386 nm and 3.23 eV, respectively. The hybrid thin films were prepared by a simple spray-coating method, which is a low-cost, fast and scalable film-forming technique. The surface roughness and also the wetting properties of the two-component hybrid layers proved to be finely adjustable by the LDO:fluoropolymer ratio. It was found that at 80–90 wt% LDO content, the thin films with a surface free energy value of ∼12 mJ/m 2 displayed superhydrophobic behaviour (Θ > 150°) with satisfactory photocatalytic properties. This means special photoreactive surfaces with superhydrophobic properties instead of the conventional superhydropilic photocatalyst layers. According to the benzoic acid photodegradation test experiments of benzoic acid, the hybrid layers with 80–90 wt% LDO content photooxidized 22–24% of the initial test molecule concentration (0.17 g/L) under UV-A (λ max = 365 nm) illumination. [ABSTRACT FROM AUTHOR]

[Display omitted] • Imide-functionalized PSMM was prepared by self-stabilized precipitation polymerization. • PSMM-HDI with isocyanate group formed via reaction with hexamethylene diisocyanate. • Nano-TiO 2 loading on the surface of PSMM-HDI through reaction of isocyanate group. • MB degradation efficiency by PSMM-HDI@TiO 2 reach 100% after 90 min UV irradiation. Polymer-supported catalysts have attracted intensive research attentions due to easy handling, facile separation and outstanding recycling performance. Herein, a simple, efficient and universal strategy was developed to fabricate isocyanate-functionalized polymer microspheres bearing highly reactive surface isocyanate groups, which could serve as a versatile support for the immobilization of photocatalyst. Firstly, self-stabilized precipitation polymerization of maleimide, maleic anhydride and styrene was performed in the presence of divinyl benzene (crosslinker) to prepare imide-functionalized poly(styrene- co -maleimide- co -maleic anhydride) (PSMM) microspheres. By simply adjusting the solvent composition and monomer feed ratio, monodisperse PSMM particles with diameter in the range of 0.52–1.01 μm were successfully obtained, which were further modified with hexamethylene diisocyanate (HDI). As a proof-of-concept, TiO 2 nanoparticles were readily and covalently bound to the surface of HDI-functionalized PSMM (PSMM-HDI) particles through reaction with isocyanate groups, leading to the formation of PSMM-HDI supported TiO 2 (PSMM-HDI@TiO 2). Furthermore, anhydride groups on the surface of PSMM was hydrolyzed to endow PSMM-HDI@TiO 2 with better dispersibility and adsorption performance. The degradation of methylene blue under UV-light was performed to evaluate the photocatalytic performance of the resultant PSMM-HDI@TiO 2. Compared with pristine TiO 2 , the PSMM-HDI@TiO 2 exhibited not only higher degradation efficiency, but also facile separation and better reusability. [ABSTRACT FROM AUTHOR]

Abstract For the development of a lightweight, high-strength, and oxidation-resistant steel matrix composite, titanium carbide (TiC) reinforced SUS431 metal matrix composites (MMCs) were proposed in this study. TiC–SUS431 composite, which is 25.5% lighter than SUS431, was successfully fabricated by a liquid pressing infiltration (LPI) process. The TiC particles are homogenously distributed in the SUS431 matrix without apparent pores or impurities. Effect of TiC particle size on the anti-oxidation properties of the composites was also investigated in the research. The mass gain of the tested TiC(1 μm)–SUS431 composite, held at 700 °C for 50 h in an air environment, decreased by about 90% compared to that of the TiC(3 μm)–SUS431 composite, which indicates improved oxidation resistance originating from the formation of a thermally stable thin Ti oxides on the composite. Graphical abstract Unlabelled Image Highlights • Fabrication of TiC reinforced SUS431 composite by a liquid pressing infiltration (LPI) process • Highly improved oxidation resistance of the TiC–SUS431 composite by introducing fine TiC particles • Formation of thermodynamically stable, volume-expanded thin TiO 2 phase in the oxidized surface [ABSTRACT FROM AUTHOR]

Graphical abstract Highlights • A thin layer of gold was coated on an aluminum dimple array and then heated. • The gold layer was transformed into numerous gold particles by the thermal treatment. • The transformation rate increases with the temperature of the thermal treatment. • Multiply-twinned particles were distributed on the surface. • The gold particle array exhibited excellent adhesion properties. Abstract Gold nanoparticles were fabricated on an ordered aluminum dimple array via aluminum anodizing, sputter coating, and thermal treatment, and the transformation behavior and nanostructural characterization were investigated in detail. Electropolished aluminum specimens were anodized in an oxalic acid solution under self-ordering conditions at 40 V, and then the porous alumina was selectively dissolved to expose an ordered aluminum dimple array with each dimple measuring 100 nm. A thin layer of gold was coated onto the dimple array, and a thermal treatment was subsequently performed. The gold layer was transformed into numerous particles by the thermal treatment due to dewetting. When the values of gold layer thickness, thermal treatment temperature, and thermal treatment duration were optimized, the gold particles were located at the bottom of each aluminum dimple. Consequently, multiply-twinned particles with polygonal and elliptical shapes were regularly distributed on the aluminum dimple array treated at 473 K. Although the rate of the transformation induced by dewetting increased with the temperature of the thermal treatment, non-uniform gold nanostructures were formed by extended thermal treatment at 873 K. The gold particles formed on the aluminum surface exhibited excellent adhesion upon ultrasonication. [ABSTRACT FROM AUTHOR]

For a known material, the size distribution of a nanoparticle colloid is a crucial parameter that defines its properties. However, measured size distributions are not easy to interpret as one has to consider weighting (e.g. by light absorption, scattering intensity, volume, surface, number) and the way size information was gained. The radius of a suspended nanoparticle can be given as e.g. sphere equivalent, hydrodynamic, Feret or radius of gyration. In this study, gold nanoparticles in water are synthesized by pulsed-laser ablation (LAL) and fragmentation (LFL) in liquids and characterized by various techniques (scanning transmission electron microscopy (STEM), small-angle X-ray scattering (SAXS), analytical disc centrifugation (ADC), dynamic light scattering (DLS) and UV–vis spectroscopy with Mie-Gans Theory) to study the comparability of different analytical techniques and determine the method that is preferable for a given task related to laser-generated nanoparticles. In particular, laser-generated colloids are known to be bimodal and/or polydisperse, but bimodality is sometimes not analytically resolved in literature. In addition, frequently reported small size shifts of the primary particle mode around 10 nm needs evaluation of its statistical significance related to the analytical method. Closely related to earlier studies on SAXS, different colloids in defined proportions are mixed and their size as a function of the nominal mixing ratio is analyzed. It is found that the derived particle size is independent of the nominal mixing ratio if the colloid size fractions do not overlap considerably. Conversely, the obtained size for colloids with overlapping size fractions strongly depends on the nominal mixing ratio since most methods cannot distinguish between such fractions. Overall, SAXS and ADC are very accurate methods for particle size analysis. Further, the ability of different methods to determine the nominal mixing ratio of sizes fractions is studied experimentally. [ABSTRACT FROM AUTHOR]

[Display omitted] • RuO x doping stimulates the high NH 3 -SCR activity of V 2 O 5 -WO 3 /TiO 2 catalyst at low-temperature. • Doping of RuO x promotes the formation of more reactive monodentate nitrates on the surface of V 2 O 5 -WO 3 /TiO 2. • The unique redox cycle and acid cycle matching mechanism consisting of monodentate nitrates and B acid sites on the RuO 2 -V 2 O 5 -WO 3 /TiO 2 surface is formed through L-H mechanism. • RuO x doping accelerates the transfer of oxygen ions on the surface of V 2 O 5 -WO 3 /TiO 2. As a mainstream moderate-high temperature (250–420 °C) particulate denitrification catalyst, V 2 O 5 -WO 3 /TiO 2 (VWT) is not applicable to low-temperature (60–150 °C) iron ore sintering flue gas after semi dry/wet desulfurization. In order to improve the NH 3 -deNO x performance of the VWT particle catalyst at low temperatures, a series of powder VWT denitrification catalysts doped with different content of RuO 2 (R-VWT) prepared by the wet co-impregnation method were researched, and found that the particulate catalyst service temperature (about 100 % NO conversion) is lowered from 225 °C (VWT) to below 175 °C by doping 0.5 % RuO 2. In addition, a series of characterizations indicate that the doped RuO 2 enhances the redox performance of R-VWT and promotes the generation of more surface active intermediate monodentate nitrate, and accelerates the low-temperature surface SCR transient reaction rate. [ABSTRACT FROM AUTHOR]

The impact processes of Ni particles at initial temperature of 900 K on Al, Cu and Steel substrates were numerically analyzed by using ANSYS/LS-DYNA. Initial kinetic energy of the particle dissipated to particle and substrate simultaneously, the proportion of which was defined as energy distribution coefficient ( K ). The K values for Ni/Al, Ni/Cu and Ni/steel combinations were approximated to 4, 0.4 and 0.1, respectively. Individual Ni60 particles were deposited experimentally onto 6061–T6 aluminum alloy, copper and 304 stainless steel by High Velocity Oxy-fuel (HVOF) spraying. The contact between Ni particles and three substrates was not perfect. The bonding ratio, which is the effective contact area divided by total area, for Ni/Cu combination is 55.41%, larger than those for Ni/Al (40.78%) and Ni/steel (32.70%) combinations, indicating that moderate K value is beneficial for interface bonding between particle and substrate. [ABSTRACT FROM AUTHOR]

Material erosion caused by continuous particle impingement during hydraulic fracturing results in significant economic loss and increased production risks. The erosion process is complex and has not been clearly explained through physical experiments. To address this problem, a multiple particle model in a 3D configuration was proposed to investigate the dynamic erosion process. This approach can significantly reduce experiment costs. The numerical model considered material damping and elastic-plastic material behavior of target material. The effects of impact parameters on erosion characteristics, such as plastic deformation, contact time, and energy loss rate, were investigated. Based on comprehensive studies, the dynamic erosion mechanism and geometry evolution of eroded crater was obtained. These findings can provide a detailed erosion process of target material and insights into the material erosion caused by multiple particle impingement. [ABSTRACT FROM AUTHOR]

Superhydrophobic surfaces have been prepared from three different types of diatomaceous earth (DE) particles treated with 3-(heptafluoroisopropoxy)propyltrimethoxysilane (HFIP-TMS) and low molecular mass polystyrene. The untreated particles, consisting of CelTix DE (disk shape), DiaFil DE (rod shape) and EcoFlat DE (irregular), were studied using particle size analysis, bulk density, pore volume and surface area analysis (via Brunauer–Emmett–Teller, BET, methods). The treated particles were characterized with thermogravimetric analysis (TGA), contact angles, scanning electron microscopy, profilometry, and FTIR spectroscopy. The minimum amount of silane coupling agent on the DE surfaces required to obtain superhydrophobicity of the particles was determined and found to be dependent on the particle morphology. In the coatings made from different particles with 2.4 wt% HFIP-TMS, the minimum amounts of treated particles (loadings) for superhydrophobicity was determined with the less dense CelTix DE requiring about 30 wt%, DiaFil DE requiring about 40 wt%, and EcoFlat DE each requiring about 60 wt% loading of treated particles. [ABSTRACT FROM AUTHOR]

[Display omitted] • Synthesis of SiO 2 @EVA core–shell particles with polydisperse particle sizes by post-emulsification method. • The ratio of the rubber shell thickness to the SiO 2 core diameter (τ) is determined by the weight ratio of them. • The value of τ has nothing to do with the SiO 2 particle size. • The critical value of τ that brittle-ductile transition happens in PA6/SiO 2 @EVA core–shell toughening system with polydisperse particle sizes is 0.069. Core-shell particles with rigid core and soft rubber shell have been proven to be effective in strengthening and toughening polymers simultaneously when the rubber shell thickness is controlled within a critical range. However, the critical value of the so-called thickness-to-diameter ratio τ (the ratio of the rubber shell thickness to the rigid core diameter) obtained in the previous work are all from polymer blends containing core–shell particles with monodispersed particle size. Does the critical τ value still exist in the core–shell toughening system with polydisperse particle sizes? Is it possible to produce core–shell particles with polydisperse particle sizes but the same τ value? In this paper, the post-emulsification method is first reported to prepare core–shell particles with polydisperse SiO 2 particles as the rigid core and ethylene–vinyl acetate copolymer grafted maleic anhydride (EVA- g -MAH) as the rubber shell, in which the thickness of the rubber shell can be well controlled and tuned via varying the feeding weight ratio of SiO 2 and EVA- g -MAH. The τ value is only determined by the weight ratio of SiO 2 and rubber, and has nothing to do with the SiO 2 particle size. A series of polyamide 6 (PA6)/SiO 2 @EVA core–shell toughening systems are prepared via melt blending process. It is proved the existence of the critical τ value (τ cbd) above which brittle-ductile transition happens in the core–shell toughening system with polydisperse core–shell particle sizes. The value of τ cbd is 0.069 in PA6/SiO 2 @EVA core–shell toughening system. [ABSTRACT FROM AUTHOR]

The present study discusses the development of a simulation model of transient impact between a particle and a substrate. The equations for structural behavior are coupled with those of heat transfer, wherein material properties are taken as temperature dependent. The set of equations is solved with Ansys program using a direct coupling method. At first, structural model is solved without heat transfer. Then, coupled thermo-mechanical model is solved with and without thermoelastic effects. Computational results indicate that thermal consideration has significant effects on contact problem. In addition, it is shown that, themoelasticity consideration is crucial for simulating these problems to determine the structural and thermal parameters. [ABSTRACT FROM AUTHOR]

Graphical abstract The effect of magnetic nanoparticle assembly formation at a planar interface between a transformer oil-based ferrofluid and Si monocrystal under non-homogeneous magnetic fields was studied by specular neutron reflectometry. The ferrofluid probed represents a stable suspension of dispersed iron oxide nanoparticles (characteristic size about 10 nm) coated with oleic acid in a low-polarity liquid carrier (transformer oil). It was shown that the reflectivity curves are sensitive to the application of a non-homogeneous external magnetic field. Highlights • Neutron reflectometry was used to describe structure of oil-based ferrofluid at nanoscale. • The ordering of magnetic nanoparticles was studied at interface fluid/solid. • Effect of magnetic field on ferrofluid's structure at interface has a threshold character. • Magnetic nanoparticle assembly formation at a planar interface was detected. Abstract The effect of magnetic nanoparticle assembly formation at a planar interface between a transformer oil-based ferrofluid and single-crystal silicon under non-homogeneous magnetic fields was studied by specular neutron reflectometry. The ferrofluid probed represents a stable suspension of dispersed iron oxide nanoparticles (characteristic size about 10 nm) coated with oleic acid in a low-polarity liquid carrier (transformer oil). It was shown that the reflectivity curves are sensitive to the application of a non-homogeneous external magnetic field. In particular, at a low magnetic flux density (<35 mT) they are well described in terms of the simplest model of a strict boundary between two semi-infinite homogeneous media. Nevertheless, slight concentrating of the ferrofluid bulk at the interface was detected. At a high magnetic flux density (35–75 mT), the analysis gives a three-layered structure of in-depth profiles of the scattering length density, thus showing the formation of two effective adsorption layers with different content of magnetic nanoparticles in them. [ABSTRACT FROM AUTHOR]

In the fabrication of a high-temperature superconducting coated conductor, the surface roughness and texture of buffer layers can significantly affect the epitaxially grown superconductor layer. A biaxially textured MgO buffer layer fabricated by ion beam assisted deposition (IBAD) is widely used in the coated conductor manufacture due to its low thickness requirement. In our previous study, a new method called energetic particle self-assisted deposition (EPSAD), which employed only a sputtering deposition apparatus without an ion source, was proposed for fabricating biaxially textured MgO films on non-textured substrates. In this study, our aim was to investigate the deposition mechanism of EPSAD-MgO thin films. The behavior of the surface roughness (evaluated by R q ) was studied using atomic force microscopy (AFM) measurements with three scan scales, while the in-plane and out-of-plane textures were measured using X-ray diffraction (XRD). It was found that the variations of surface roughness and textures along with the increase in the thickness of EPSAD-MgO samples were very similar to those of IBAD-MgO reported in the literature, revealing the similarity of their deposition mechanisms. Moreover, fractal geometry was utilized to conduct the scaling analysis of EPSAD-MgO film's surface. Different scaling behaviors were found in two scale ranges, and the indications of the fractal properties in different scale ranges were discussed. [ABSTRACT FROM AUTHOR]

Over the past decade, researchers have demonstrated much interest in laser cladded metal matrix composite coatings for its good wear resistance, corrosion resistance, and high temperature properties. In this paper, in-situ (Ti, Nb)C particle reinforced Fe-based composite coatings were produced by laser cladding. The effects of Ti/Nb(atomic ratio) in the cladding powder on the formation mechanism and distribution characteristics of multiple particle were investigated. The results showed that when Ti/Nb > 1, Ti had a stronger ability to bond with C compared with Nb. (Ti, Nb)C multiple particles with TiC core formed in the molten pool. With the decrease of Ti/Nb, core-shell structure disappeared, the structure of particle got close to that of NbC gradually. It is found that the amount, area ratio and distribution of the reinforced particle in the coating containing Ti and Nb elements were improved, compared with these in the coating containing equal Nb element. When Ti/Nb = 1, the effects above-mentioned is most prominent, and the wear resistance of the coating is promoted obviously. [ABSTRACT FROM AUTHOR]

We sputter-deposited Pt nanoparticles with an average size ranging from 2.0 nm to 8.5 nm on the indium-tin oxide (ITO) glass substrate, and studied the effect of the size of Pt nanoparticles on electrocatalytic activity of the Pt/ITO electrode toward methanol oxidation reaction (MOR) in acidic solution. X-ray photoelectron spectroscopy (XPS) reveals an interfacial oxidized Pt layer present between Pt nanoparticles and the ITO substrate, which may modify the surface electronic structure of Pt nanoparticles and thus influences the electrocatalytic properties of the Pt catalyst toward MOR. According to electrochemical analyses, smaller Pt nanoparticles exhibit slower kinetics for CO electrooxidation and MOR. However, a smaller particle size enables better CO tolerance because the bifunctional mechanism is more effective on smaller Pt nanoparticles. The electrocatalytic activity decays rapidly for Pt nanoparticles with a size smaller than 3 nm and larger than 8 nm. The rapid activity decay is attributed to Pt dissolution for smaller nanoparticles and to CO poisoning for larger ones. Pt nanoparticles of 5–6 nm in size loaded on ITO demonstrate a greatly improved electrocatalytic activity and stability compared with those deposited on different substrates in our previous studies. [ABSTRACT FROM AUTHOR]

In this work, we report on a technique to reduce gold chloride into sub-micron particles and nanoparticles. We use photoelectron transfer from periodically polarized lithium niobate (PPLN) illuminated with above band gap light to drive the surface reactions required for the reduction and particle formation. The particle sizes and distributions on the PPLN surface are sensitive to the solution concentration, with inhibited nucleation and large particles (>150 nm) for both low (2E−8M to 9E−7M) and high (1E−5M to 1E−3M) concentrations of gold chloride. At midrange values of the concentration, nucleation is more frequent, resulting in smaller sized particles (<150 nm). We compare the deposition process to that for silver, which has been previously studied. We find that the reduction of gold chloride into nanoparticles is inhibited compared to silver ion reduction, due to the multi-step reaction required for gold particle formation. This also has consequences for the resulting deposition patterns: while silver deposits into nanowires along boundaries between areas with opposite signed polarizations, such patterning of the deposition is not observed for gold, for a wide range of concentrations studied (2E−8 to 1E−3M). [ABSTRACT FROM AUTHOR]

The subsurface damage and surface integrity of a spherical diamond indenter sliding against a face-centred cubic copper (100) surface considering the pore and second-phase particle effects is investigated by means of molecular dynamic simulations of nanoindentation followed by nanomachining. In this investigation, we establish an analytical model for pore healing, and provide a criteria to determine whether or not pore can be healed. The results show that with increase of machining distance pore becomes smaller and then closes due to machining-induced compressive stress, resulting in low material damage and strong structure stability. Compared to free pore workpiece, machining force slightly relies upon the existence of pore and second-phase particle while friction coefficient strongly depends on the existence of that. In addition, particle induces work hardening due to Lomere-Cottrel lock and dislocation slip during machining metal matrix composites. It is helpful to understand the relation of machining performance and material parameter for obtaining higher surface integrity and lower subsurface damage during machining porous metals and particle reinforced metal matrix composites. [ABSTRACT FROM AUTHOR]

[Display omitted] • Paraffin dispersion was costabilized by W-doped VO 2 nanoparticles and chitosan. • Functional nanocellulose (NC) film was made of NC fibers and paraffin dispersion. • The paraffin dispersion improves the hydrophobicity and tensile strength of NC film. • The functional NC film has improved privacy protection and thermal insulation. The development of functional window films for energy savings and privacy protection has attracted considerable attention. Herein, a functional nanocellulose film was fabricated via a papermaking technique by using the naturally formed network structure of nanocellulose film to obtain privacy protection and to encapsulate paraffin particles stabilized by W-doped VO 2 nanoparticles and chitosan. The paraffin particles stabilized by W-doped VO 2 nanoparticles and chitosan were prepared via an emulsion approach without using surfactant. The incorporation of paraffin into the nanocellulose film not only enhances the latent heat and lowers the forward transmittance of the nanocellulose film but also improves its hydrophobicity. The presence of a small amount of W-doped VO 2 nanoparticles in the paraffin particle dispersion further increases the forward transmittance and latent heat of the nanocellulose film, especially at elevated temperatures. Meanwhile, the introduction of chitosan in the paraffin particle dispersion significantly improves the toughness of the nanocellulose film. Consequently, the incorporation of paraffin particles endows the nanocellulose film with hydrophobicity and toughness as well as good privacy protection and thermal insulation for energy savings at both room and elevated temperatures, making the as-prepared nanocellulose film a promising functional window film. [ABSTRACT FROM AUTHOR]

In this paper, the transient behavior of the particle assembly yield dynamics when switching from low yield to high yield deposition at different velocity and thermal regimes is investigated. Capillary force assisted particle assembly (CAPA) using colloidal suspension of green fluorescent 270 nm diameter polystyrene beads was performed on patterned poly (dimethyl siloxane) substrates using a custom-built deposition setup. Two types of patterns with different trapping site densities were used to assess CAPA process dynamics and the influence of pattern density and geometry on the deposition yield transitions. Closely packed 300 nm diameter circular pits ordered in hexagonal arrangement with 300 nm pitch, and 2 × 2 mm 2 square pits with 2 μm spacing were used. 2-D regular structures of the deposited particles were investigated by means of optical fluorescence and scanning electron microscopy. The fluorescence micrographs were analyzed using a custom algorithm enabling to identify particles and calculate efficiency of the deposition performed at different regimes. Relationship between the spatial distribution of particles in transition zone and ambient conditions was evaluated and quantified by approximation of the yield profile with a logistic function. [ABSTRACT FROM AUTHOR]

This work reports on the erosion performance of three particle reinforced metal matrix composite coatings, co-deposited with an aluminium binder via cold-gas dynamic spraying. The deposition of ceramic particles is difficult to achieve with typical cold spray techniques due to the absence of particle deformation. This issue has been overcome in the present study by simultaneously spraying the reinforcing particles with a ductile metallic binder which has led to an increased level of ceramic/cermet particles deposited on the substrate with thick (>400 μm) coatings produced. The aim of this investigation was to evaluate the erosion performance of the co-deposited coatings within a slurry environment. The study also incorporated standard metallographic characterisation techniques to evaluate the distribution of reinforcing particles within the aluminium matrix. All coatings exhibited poorer erosion performance than the uncoated material, both in terms of volume loss and mass loss. The Al 2 O 3 reinforced coating sustained the greatest amount of damage following exposure to the slurry and recorded the greatest volume loss (approx. 2.8 mm 3 ) out of all of the examined coatings. Despite the poor erosion performance, the WC-CoCr reinforced coating demonstrated a considerable hardness increase over the as-received AA5083 (approx. 400%) and also exhibited the smallest free space length between adjacent particles. The findings of this study reveal that the removal of the AA5083 matrix by the impinging silicon carbide particles acts as the primary wear mechanism leading to the degradation of the coating. Analysis of the wear scar has demonstrated that the damage to the soft matrix alloy takes the form of ploughing and scoring which subsequently exposes carbide/oxide particles to the impinging slurry. [ABSTRACT FROM AUTHOR]

Hierarchical Ag mesostructures with highly rough surface morphology have been synthesized at room temperature through a simple seed-mediated approach. Electron microscopy characterizations indicate that the obtained Ag mesostructures exhibit a textured surface morphology with the flower-like architecture. Moreover, the particle size can be tailored easily in the range of 250–500 nm. For the growth process of the hierarchical Ag mesostructures, it is believed that the self-assembly mechanism is more reasonable rather than the epitaxial overgrowth of Ag seed. The oriented attachment of nanoparticles is revealed during the formation of Ag mesostructures. Single particle surface enhanced Raman spectra (sp-SERS) of crystal violet adsorbed on the hierarchical Ag mesostructures were measured. Results reveal that the hierarchical Ag mesostructures can be highly sensitive sp-SERS substrates with good reproducibility. The average enhancement factors for individual Ag mesostructures are estimated to be about 10 6 . [ABSTRACT FROM AUTHOR]

Using an atomic force microscope, the friction and wear of phosphate laser glass against a CeO 2 particle were quantitatively studied both in humid air and in vacuum, to reveal the water molecules induced mechanochemical wear mechanism of phosphate laser glass. The friction coefficient of the glass/CeO 2 pair in air was found to be 5–7 times higher than that in vacuum due to the formation of a capillary water bridge at the friction interface, with a contribution of the capillary-related friction to the total friction coefficient as high as 65–79%. The capillary water bridge further induced a serious material removal of glass and CeO 2 particle surfaces, while supplying both a local liquid water environment to corrode the glass surface and a high shearing force to assist the stretching of the Ce O P bond, accelerating the reaction between water and the glass/CeO 2 pair. In vacuum, however, no discernable wear phenomena were observed, but the phase images captured by AFM tapping mode suggested the occurrence of potential strain hardening in the friction area of the glass surface. [ABSTRACT FROM AUTHOR]

Antibodies have received significant attention for use as antibody drugs, because they bind the objective protein (antigen) via antigen–antibody reactions. Recently, many reports have appeared on various monoclonal antibodies that recognize a single antigen. In this study, monoclonal antibodies are used as adsorbates on mesoporous silica (MPS) for affinity chromatography. MPS has high surface area and large pore volume; moreover, pore diameter, pore structure, and particle morphology are relatively easy to tune by adjusting the conditions of synthesis. The pore structure (two-dimensional (2D) hexagonal and three-dimensional cubic) and particle morphology (spherical and polyhedral) of MPS are optimized for use in a monoclonal antibody/MPS composite. When anti-IgG (one of the monoclonal antibodies) adsorbs on the MPS material and IgG (antigen) binds to anti-IgG/MPS composites, MCM-41p with a 2D-hexagonal pore structure and polyhedral particle morphology has the highest IgG binding efficiency. In addition, the antibody/MPS composites remain stable in chaotropic and low-pH solutions and can be cycled at least five times without decreasing IgG elution. In purification and removal tests, the use of the antibody/MPS composites allows only the objective protein from protein mixtures to be bound and eluted. [ABSTRACT FROM AUTHOR]

[Display omitted] • As the powder particle size of the APS coating decreases, the density of the microstructure increases. • Surface YO x F y layer creation and etching by physical (ion bombardment) and chemical (radical) reaction. • Plasma corrosion resistance improved with increasing density of APS-Y 2 O 3 coating. • Reduced contaminant particle generation through APS coating powder particle control. The atmospheric plasma spray (APS) -Y 2 O 3 coatings are widely used to minimize damage to internal parts of the chamber caused by the strong corrosive effect of fluorine-based plasma used in dry etching; however, the poor density of APS-Y 2 O 3 coatings results in low plasma corrosion resistance. This is a major cause of the generation of contamination particles during CF 4 /O 2 plasma etching. Hence, defects inside the coating must be eliminated to improve the plasma corrosion resistance of APS-Y 2 O 3 coatings. The correlation between the decrease in the number of defects inside the APS-Y 2 O 3 coatings according to the powder particle size and the surface corrosion process by CF 4 /O 2 plasma etching was confirmed. We verified that the internal defects in APS-Y 2 O 3 coatings can be controlled with small powder particles because the powder particles in the APS layer melt efficiently under the APS coating conditions; in addition, the fluorine content rate inside the coating is improved. After the focused ion beam (FIB) process, by examining YO x F y layer with a field emission scanning electron microscope (FE-SEM), energy dispersive X-ray spectroscopy (EDS), and X-ray photoelectron spectroscopy (XPS); we observed the formation of a thick YO x F y layer with decreasing number of defects inside the APS-Y 2 O 3 coatings; thereby, the bonding strength among the Y 2 O 3 powder particles was increased, and corrosion of YO x F y layer due to physical and chemical reactions decreased; as a result, the etch amount was significantly reduced. Therefore, it can be seen that the generation of contamination particles in the CF 4 /O 2 plasma etching can be reduced by controlling the occurrence of defects inside the APS-Y 2 O 3 coatings. The results of this study demonstrate the possibility of minimizing the effect of contamination particles generated in the dry etching process to remove YO x F y layer using chamber self-cleaning such as waferless step. This paper presents a new direction for controlling contamination particles in the inner coating parts of the plasma etching chamber. [ABSTRACT FROM AUTHOR]

Carbon steel with dispersed nano-sized TiC ceramic particles was fabricated by the ex-situ introduction of the particles into the melt, with the flow-assisted corrosion (FAC) resistance then investigated in the presence and absence of TiC nanoparticles using a once-through type of FAC loop test. From the potentiodynamic polarization curves, the current density at any given anodic potential was decreased and the open-circuit potential was increased by the addition of TiC nanoparticles. In addition, when the nano-sized TiC particles were added, the FAC rate was 1.38 times lower than that of carbon steel without TiC nanoparticles, indicating an improvement of the FAC resistance due to the homogeneous distribution of the TiC reinforcing nanoparticles. [ABSTRACT FROM AUTHOR]

In this paper, the dynamic impact behavior of a particle and a substrate under different particle temperatures and velocities as well as using different materials for the particle and substrate were systematically studied. We found that the highest temperature occurred at the side edge of the particle after the collision, which is consistent with the distribution of equivalent plastic strain. The deformation of the particle and substrate was very severe at the first 40 ns, slowed down after 40 ns and remained almost unchanged after 80 ns. With the increase in the particle velocity, the effective combination area became larger, the equivalent plastic strain of the substrate is increased, and the equivalent plastic strain of the particle is decreased. As the initial temperature of particles increased, the effective combination area between the particle and substrate increased, and higher temperature and larger equivalent plastic strain of the particle could be obtained. With the increase in the substrate strength, the temperature and the equivalent plastic strain of the particle is increased, whereas the plastic deformation of the substrate is decreased. [ABSTRACT FROM AUTHOR]

[Display omitted] • A novel coating on DBMPs enhances biocompatibility and facilitates cell capture and release. • A comparative analysis of CTCs capture and release efficiencies across different particle sizes. • The optimized DBMP3 shows high efficiency of CTCs capture and release. Circulating tumor cells (CTCs) are critical biomarkers in cancer metastasis, yet their isolation from the bloodstream remains a challenging task due to their low abundance. This study introduces a method for the efficient isolation of CTCs, utilizing dynamic biointerface-based magnetic particles (DBMPs), with a particular emphasis on the role of particle size. We have developed three distinct sizes DBMPs specifically tailored for effective CTCs interaction, leveraging the unique properties of polydopamine (PDA) coatings and phenylboronic acid (PBA)-modified capture peptides through reversible catechol-boronate interactions. Comparative analysis of DBMPs of varying sizes was assessed under uniform experimental conditions for their capture and release efficiencies. The findings reveal a clear distinction: smaller particles (DBMP1 and DBMP2) achieved greater efficiency in capturing CTCs, whereas the larger particles (DBMP3) were more effective in releasing them. This difference is ascribed to the varied interaction dynamics between the particles and CTCs. Furthermore, we have fine-tuned DBMP3 to optimize CTC capture while still maintaining a high efficiency in cell release. The integration of these DBMPs into a magnetic isolation framework is poised to significantly enhance CTCs isolation methods, marking a pivotal advancement in cancer diagnostics and management. [ABSTRACT FROM AUTHOR]