Dense Substrates Research Articles

Addressing molecular geometry on dense gold nanoparticle substrates by two-colour sum-frequency generation spectroscopy combined with DFT calculations

Addressing molecular geometry on dense gold nanoparticle substrates by two-colour sum-frequency generation spectroscopy combined with DFT calculations

Findings and perspectives of β-Ti alloys with biomedical applications: Exploring beyond biomechanical and biofunctional behaviour

Early implant failure and bone resorption may occur in load-bearing conditions as a result of stress shielding brought on by a mismatch in the bone-Ti-implant modulus. A review with a novel multidisciplinary perspective is proposed in this work, which considers recent developments of β-Titanium alloys and new trends in novel microstructures, processing techniques, properties of dense and porous substrates, as well as the relationship between all these aspects and performance in service, in terms of improved its biomechanical and bio-functional balance. In addition to highlighting several modern and historical uses for Ti alloys, this review covers many cutting-edge novel β-Ti alloys and uses that promise to exceed historical standards. Also, it deepens through several important properties of these alloys, including toxicity of alloying elements, phase stability, thermo-mechanical processing, heat treatment, surface, and stress-induced modifications. The stiffness, hardness, fatigue and wear resistance, corrosion behaviour, biocompatibility, and manufacturing and surface modification effects on these parameters are also emphasized. In-vitro and in-vivo assays have been added to highlight important aspects of bioactivity and antibacterial behaviour, and future significant research areas are suggested along with new techniques to ensure the successful clinical application of β-Ti alloys.

A Novel Biomineralized Collagen Liquid Crystal Hydrogel Possessing Bone-like Nanostructures by Complete In Vitro Fabrication.

The microstructure of bone consists of nano-hydroxyapatite (nano-HA) crystals aligned within the interspaces of collagen fibrils. To emulate this unique microstructure of bone, this work applied two biomimetic techniques to obtain bone-like microstructures in vitro, that is, combining the construction of collagen liquid crystal hydrogel (CLCH) with the application of a polymer-induced liquid precursor (PILP) mineralization process. Upon the elevation of pH, the collagen macromolecules within the collagen liquid crystal (CLC) were activated to self-assemble into CLCH, whose fibrils packed into a long and dense fiber bundle in high orientation, emulating the dense-packed matrix of bone. We demonstrated that the fibrillar mineralization of CLCH, leading to a bone-like nanostructured inorganic material part, can be achieved using the PILP crystallization process to pre-mineralize the dense collagen substrates of CLCH with CaCO3, immediately followed by the in situ mineral phase transformation of CaCO3 into weak-crystalline nano-HA. The combination of CLCH with the biomineralization process of PILP, together with the mineral phase transformation, achieved the in vitro simulation of the nanostructures of both the organic extracellular matrix (ECM) and inorganic ECM of bone. This design would constitute a novel idea for the design of three-dimension biomimetic bone-like material blocks for clinical needs.

Fabrication of high-performance pervaporation desalination composite membranes with study of its acid-base stability

In the process of industrial production will produce a lot of acid and alkaline waste liquid, how to effectively treat acid and alkali waste liquid is an important topic at present. At present, there are some problems about the treatment of acid and alkali waste liquid, such as large investment, complicated process and low efficiency. Pervaporation has the characteristics of mild operating conditions and no influence of osmotic pressure threshold, so it has great application potential in the concentration, reuse and reduction of acid and alkali waste liquid. However, at present, conventional pervaporation dense membrane materials cannot maintain long-term stability in strong acid and alkali environment, in order to achieve this performance, we use perfluorosulfonic acid resin with good acid and alkali resistance as the dense layer substrate. PFSA/PTFE/PP composite membrane was prepared by spraying process, and the final prepared composite membrane had a pure water flux of 45 ± 1.2 kg/(m2∙h) at 70 ℃. The acid and alkali resistance of the intrinsic membrane and the composite membrane was evaluated, and it was found that the feed liquid was concentrated to 20 wt% after 19 h long concentration operation at 70℃ and starting liquid was 5 wt% H2SO4 and 5 wt% NaOH. The retention rate of acid and alkali can be maintained above 99.9 %. During the concentration of H2SO4 solution, the dense layer structure is affected, and the pure water flux of the composite membrane is reduced, eventually maintaining around 32 kg/(m2∙h). In the process of concentrating NaOH solution, the pure water flux of the composite membrane increased first and then decreased, and the final pure water flux of the membrane remained near 40 kg/(m2∙h).

Inkjet-Printed LSM-YSZ Thin Films for Enhanced Oxygen Electrodes in Solid Oxide Fuel Cells.

In the present work, symmetrical oxide ion conducting solid oxide single cells with inkjet-printed composite LSM-YSZ electrodes, onto commercially available YSZ dense substrates using GDC as buffer interlayer, were fabricated and characterized. Stable inkjet-printable LSM-YSZ nanoparticle inks were developed based on water solvent, after processing with high intensity ball milling. The deposition of LSM-YSZ electrodes was performed by inkjet printing, as well as a conventional additive manufacturing technique, screen printing, in order to compare the electrochemical performance of the produced cells for the reversible charge transfer reaction (O2 + 4 e- ↔ 2 O2-). The physicochemical properties of the LSM-YSZ nanoparticle ink was investigated to determine ink printability. The electrochemical performance of fabricated inkjet-printed and screen printed symmetrical cells (LSM-YSZ | GDC | YSZ | GDC | LSM-YSZ) exposed under a synthetic air atmosphere was evaluated in a single chamber cell reactor, employing the AC impedance spectroscopy and linear scan voltammetry techniques, at the temperature range of 700-850 °C. The inkjet-printed electrodes exhibited highly homogeneous and porous morphologies with the corresponding cell achieving current densities almost five times higher, up to 1 A/cm2 at 2 V cell potential and 850 °C, than those of the equivalent screen-printed one. To the best of our knowledge, this is the first successful implementation of water-based inks of LSM-YSZ electrodes in the fabrication of inkjet-printed solid oxide cells.

Construction of X-Co-tri@SSNF reinforced PPS composite proton exchange membranes and their performance in fuel cells

In this study, we pioneered the introduction of benzophenone (DPK) as a solid solvent into polyphenylene sulfide (PPS) melt-blown, which effectively reduced the PPS melt-blown processing temperature and significantly improved the coefficients of variation of PPS melt-blown nonwoven materials. X-Co-tri@SSNF proton exchange membranes with excellent performance were prepared by functionalized modification of PPS melt-blown fabric as a substrate. The structure and properties of X-Co-tri@SSNF proton exchange membranes were systematically characterized. The results demonstrate that the 1-Co-tri@SSNF PEM exhibited a high proton conductivity of 0.183 S cm−1 at 80 °C and high humidity, significantly higher than the commercial Nafion 117 (0.135 S cm−1). Due to the heat resistance of PPS itself and the continuous dense network structure substrate of PPS nonwoven fabrics as well as the high compatibility with the membrane casting liquid, the hybrid membrane interfaces were tightly connected, so it makes the hybrid membrane perform better in terms of mechanical stability (tensile strength of 36.7 MPa), methanol permeability (4.78 × 10−7 cm2 s−1), selectivity (16.32 × 104 S s cm−3), and thermal stability (thermal decomposition temperature of around 450 °C). In addition, the 1-Co-tri@SSNF membrane electrode module exhibited excellent single-cell performance with an open-circuit voltage of 629.91 V and a peak power density of 96.29 mW cm−2 (162.9 % higher than that of Nafion 117). Therefore, the composite PEM with PPS melt-blown fabric as the matrix has a more environmentally friendly process than the commercial Nafion 117 membrane, a theoretical guidance for advancing the large-scale production of low-cost PEM.

Multimodal electrospray thruster for small spacecraft: design and experimental characterization

Electrospray thrusters are a promising electric micropropulsion technology which could be used to meet the propulsion needs of nanosatellites, or for fine attitude control of larger spacecraft. Multimodal propulsion is the integration of two or more propulsion modes into a system which utilizes a common propellant. Indeed, spacecraft mission simulations and models have shown that this type of multimode propulsion capacity is exciting because of the flexibility and adaptability it provides mission designers and planners. A single spacecraft would have potential to execute drastically different mission profiles, and the exact mission could even be determined post-launch. The current paper investigates a micro-propulsion system which combines a droplet and ion mode electrospray emitter into a unified multimodal system (using an ionic liquid as the common propellant for both systems). The high relative thrust droplet mode emitter was fabricated from P3 borosilicate glass while the high efficiency ion mode emitter, Carbon Xerogel dense porous substrate, was fabricated in-house. To characterize the multimodal thruster, a full beam and time-of-flight (ToF) experimental setup were developed at the RMC Advanced Propulsion and Plasma Exploration Laboratory (RAPPEL) and experiments were conducted using a custom vacuum chamber. The ion mode emitter, with a beam comprised purely of ions had an onset voltage around 1400 V with an estimated thrust performance of 0.14 μN\\documentclass[12pt]{minimal} \\usepackage{amsmath} \\usepackage{wasysym} \\usepackage{amsfonts} \\usepackage{amssymb} \\usepackage{amsbsy} \\usepackage{mathrsfs} \\usepackage{upgreek} \\setlength{\\oddsidemargin}{-69pt} \\begin{document}$$\\mu N$$\\end{document} and specific impulse of 4040 s. For droplet mode, with a mixed beam comprised of around 17%\\documentclass[12pt]{minimal} \\usepackage{amsmath} \\usepackage{wasysym} \\usepackage{amsfonts} \\usepackage{amssymb} \\usepackage{amsbsy} \\usepackage{mathrsfs} \\usepackage{upgreek} \\setlength{\\oddsidemargin}{-69pt} \\begin{document}$$\\%$$\\end{document} droplets and 83%\\documentclass[12pt]{minimal} \\usepackage{amsmath} \\usepackage{wasysym} \\usepackage{amsfonts} \\usepackage{amssymb} \\usepackage{amsbsy} \\usepackage{mathrsfs} \\usepackage{upgreek} \\setlength{\\oddsidemargin}{-69pt} \\begin{document}$$\\%$$\\end{document} ions, an onset voltage of 1375 V with an estimated performance of thrust at 14 μN\\documentclass[12pt]{minimal} \\usepackage{amsmath} \\usepackage{wasysym} \\usepackage{amsfonts} \\usepackage{amssymb} \\usepackage{amsbsy} \\usepackage{mathrsfs} \\usepackage{upgreek} \\setlength{\\oddsidemargin}{-69pt} \\begin{document}$$\\mu N$$\\end{document} and specific impulse of 140 s were measured. The prototype thruster demonstrates how various electrospray emitters could be combined into a multimodal system to provide flexibility and adaptability in providing effective thrust for small satellites.

Characteristics of a CaO–B2O3–SiO2–Al2O3–ZnO-based sandwich substrate and its dielectric properties in the 5G millimeter-wave band

In this study, a 34.5CaO–23B2O3–33.5SiO2–6Al2O3–3ZnO (CBSAZ) glass-ceramic substrate was prepared using a sol–gel method. A porous CaO–B2O3–SiO2–Al2O3–ZnO layer (CBSAZ0.5C) with a porosity of 72.6 % and thickness of 365 μm was inserted between two ∼120 μm thick dense CBSAZ layers to form a tri-layer substrate (CBSAZ/CBSAZ0.5C/CBSAZ). The dielectric constants (εr) and dielectric losses (tanδ) of the dense CBSAZ substrate at 20 and 60 GHz were 6.90 and 0.029, respectively, and 6.96 and 0.017, respectively. These values were almost independent of frequency. In contrast, the εr and tanδ values of the CBSAZ/CBSAZ0.5C/CBSAZ sandwich substrate at 20 and 60 GHz were 3.59 and 0.022, respectively, and 3.11 and 0.020, respectively. Thus, the εr value of the CBSAZ/CBSAZ0.5C/CBSAZ sandwich substrate was significantly lower than that of the CBSAZ substrate, whereas the tanδ and κ values of the CBSAZ/CBSAZ0.5C/CBSAZ and CBSAZ substrates were similar.

Spontaneous adsorption effect of graphitic carbon nitride nanosheets to improve sintering behavior of yttria-stabilized zirconia microbeads

Yttria-stabilized zirconia (YSZ) is a ceramic material in which the zirconium dioxide structure is stabilized at room temperature by adding yttrium oxide. However, the YSZ formed by the thick film process on a pre-sintered dense substrate suffers from sintering problems such as different sintering shrinkage rates due to phase transitions and thermal conductivity. This in turn can lead to de-bonding, cracking, delamination, and abnormal growth. We prepared a spherical YSZ green body of approximately 38 μm diameter formed by an organic binder based on a sintered YSZ seed with 15 to 20 μm diameter. In addition, the application of two-dimensional g-C3N4 nanosheets that can be adsorbed on the surface and pores of the green body before the sintering process was evaluated. The YSZ green body with adsorbed surface-modified g-C3N4 nanosheets could be synthesized by stable spontaneous adsorption due to zeta-potential attraction onto the surface of zirconia particles in an aqueous solution. Consequentially, the formation of large grains due to abnormal grain growth was reduced as g-C3N4 was adsorbed. The spontaneous adsorption of nanosheets controls the surface diffusion mechanism by sequentially lowering the energy from a high surface energy in the initial stage of sintering. Uniform grain growth thus can be induced according to the activation energy level of the controlled surface diffusion.

(Digital Presentation) Facile Fabrication of Nickel and Sc-Doped Zirconia Cermet Electrode Thin Film on YSZ Substrate Via Screen-Printing for Solid Oxide Electrochemical Cells

Solid oxide electrochemical cells (SOCs) operating as either solid oxide fuel cells (SOFCs) or solid oxide electrolysis cells (SOECs) are widely known as promising advancements in green energy technologies for storage and high-efficiency energy generation. This study used a single screen-printing deposition method to fabricate a porous Nickel – scandia-stabilized zirconia (Ni-ScSZ) cermet electrode on a dense YSZ solid electrolyte substrate. The precursor powders were prepared via the glycine-nitrate combustion process. To investigate the effect of ink slurry solvent on the quality, structure, and morphology of the deposited films, ethanol, and alpha-terpineol were used. The screen-printed films were sintered at 1300°C for 6h and reduced under an Ar/5% H2 gas environment at 700°C for 2h to form porous electrodes. X-ray diffraction (XRD) analysis showed that all sintered NiO-ScSZ films exhibited cubic peak structures of both NiO and ScSZ. Scanning electron microscopy (SEM) micrographs and elemental mapping revealed finer morphology with good dispersion of NiO and ScSZ phases for sintered NiO-ScSZ films with alpha-terpineol as solvent. After exposure to Ar/5% H2 gas environment, a complete reduction of NiO to Ni was revealed by XRD for all Ni-ScSZ electrodes. Moreover, SEM micrographs of as-reduced samples showed an increase in porosity as oxygen was removed from NiO. Electrochemical impedance spectroscopy was used to determine the conductivity of the reduced Ni-ScSZ electrode films under Ar/5% H2 gas environment. The obtained total conductivity values upon reduction are 9.54x10-5 S/cm and 4.75x10-5 S/cm for ethanol and alpha-terpineol as solvents, respectively.

Forelimb morphology as an adaptation for burrowing in kangaroo rat species (genus Dipodomys) that inhabit different soil substrates

Abstract Among burrowing rodents, forelimb morphology frequently shares an intricate relationship with soil substrates. Soils vary widely in texture and density, leading to differences in friability (e.g., the relative ability of particles to be broken apart), which often requires forelimb specializations in digging animals. Kangaroo rats (Dipodomys spp.) dig and occupy burrows, a trait that is essential to their survival. Some Dipodomys species are restricted to particular substrates that presumably require species-specific forelimb traits. Here we examined the forelimb morphology and soil substrates inhabited by range-restricted and widely ranging Dipodomys species to explore the variation in soil usage, forelimb specializations, and the relationship between these traits. We assessed size and shape traits of preserved specimen forelimb bones using traditional and geometric morphometric techniques and extracted soil data associated with the collecting locality of each specimen. We expected species that inhabit dense soil substrates to display specialized forelimb morphology typified by an elongated scapula and robust humerus, radius, and ulna. The species differed substantially in their soil associations and forelimb morphologies. In particular, forelimb traits that enhance mechanical digging ability were detected in D. elator, a range-restricted species that inhabits dense clay-rich soils. These findings suggest that Dipodomys species that inhabit dense substrates may require correspondingly specialized forelimb morphology and that these traits may limit the desirable geographic ranges inhabited by these species. This may provide important information when making conservation decisions given that unlike other habitat features, soil substrates cannot be easily modified to suit the needs of the organism.

(Digital Presentation) Facile Fabrication of Nickel and Sc-Doped Zirconia Cermet Electrode Thin Film on YSZ Substrate Via Screen-Printing for Solid Oxide Electrochemical Cells

Electrode materials play a key role in the performance of solid oxide electrochemical cells. In this study, screen-printing was used to fabricate a porous nickel – scandia-stabilized zirconia (Ni-ScSZ) cermet electrode on a dense YSZ solid electrolyte substrate. The effect of sintering temperatures, 1200°C and 1300°C, on the structure and morphology of the deposited films were investigated. The screen-printed films were sintered and then reduced under an Ar/5% H2 gas environment at 700°C for 2h to form porous electrodes. The sintered films exhibited NiO and ScSZ cubic phases from X-ray diffraction (XRD) analysis. A desired porous morphology of NiO-ScSZ film sintered at 1200°C was achieved compared to a denser morphology sintered at 1300°C as revealed by the scanning electron microscopy (SEM) micrographs. XRD patterns of reduced samples suggested a complete reduction of cubic NiO to Ni with an increase in porosity as observed from SEM micrographs.

Internal surface modification of additively manufactured macroporous TiAl6V4 biomimetic implants via a calciothermic reaction-based process and osteogenic in vivo responses.

Three-dimensional macroporous titanium-aluminum-vanadium (TiAl6V4) implants produced by additive manufacturing (AM) can be grit blasted (GB) to yield microtextured exterior surfaces, with additional micro/nano-scale surface features provided by subsequent acid etching (AE). However, the line-of-sight nature of GB causes the topography of exterior GB + AE-modified surfaces to differ from internal GB-inaccessible surfaces. Previous in vitro studies using dense TiAl6V4 substrates indicated that a nonline-of-sight, calciothermic-reaction (CaR)-based process provided homogeneous osteogenic nanotextures on GB + AE surfaces, suggesting it could be used to achieve a homogeneous nanotopography on external and internal surfaces of macroporous AM constructs. Macroporous TiAl6V4 (3D) constructs were produced by direct laser melting and modified by GB + AE, with the CaR process then applied to 50% of constructs (3DCaR). The CaR process yielded nanoporous/nanorough internal surfaces throughout the macroporous constructs. Skeletally mature, male Sprague-Dawley rats were implanted with these constructs using a cranial on-lay model. Prior to implantation, a Cu++-free click hydrogel was applied to half of the constructs (3D + H, 3DCaR + H) to act as a challenge to osseointegration. Osseointegration was compared between the four implant groups (3D, 3DCaR, 3D + H, 3DCaR + H) at 4w. 3D + H implants exhibited lower bone volume (BV) and percent bone ingrowth (%BI) than the 3D implants. In contrast, osseointegrated 3DCaR + H implants had similar BV and %BI as the 3DCaR implants. Implant pull-off forces correlated with these results. In vitro analyses indicated that human bone marrow stromal cells (MSCs) exhibited enhanced production of osteoblast differentiation markers and factors associated with osteogenesis when grown on CaR-modified 3D substrates relative to control (TCPS) substrates. This work confirms that the CaR process provides osteogenic nanotextures on internal surfaces of macroporous 3D implants, and suggests that CaR-modified surfaces can promote osseointegration in cases where osteogenesis is impaired.

Interfacial characteristics of bioglass diffusion zone between scaffold-like hydroxyapatite/wollastonite coating and dense zirconia substrate

A thin bioglass (BG) layer or diffusion zone has been used to enhance interfacial bonding between co-sintered scaffold-like micro-porous hydroxyapatite (HA) coating over dense zirconia substrate. However, there still have problems such as low fracture toughness and low wear resistance. Therefore, while meeting the basic requirements of degradability and biocompatibility, how to improve the mechanical properties of the scaffold, endow it with osteoinductivity and build a low-density porous structure has become the focus of bone scaffold research. The tri-layer bio-ceramic composites, consisting of porous HA, BG diffusion zone, and strong zirconia substrate, are designed with superior loading-bearing capability to the scaffold. Surface handling properties of the scaffold-like HA coating are further enhanced by incorporating wollastonite. The gradient in material compositions across the coating and substrate interface is further minimized by adding HA into the zirconia substrate. Benefiting from these special design and the thin BG diffusion zone, the tri-layer bio-ceramics present excellent interfacial strength, which ensures good structural strength and machinability. The results could provide the feasible options for bio-ceramic scaffolds design and manufacturing process, thus advance the practical clinical applications of HA-based scaffolds for bone repair and regeneration.

Electrospinning Nanofibers as Stretchable Sensors for Wearable Devices.

Wearable devices attract great attention in intelligent medicine, electronic skin, artificial intelligence robots, and so on. However, boundedness of traditional sensors based on rigid materials unconstrained self-multilayer structure assembly and dense substrate in stretchability and permeability limits their applications. The network structure of the elastomeric nanofibers gives them excellent air permeability and stretchability. By introducing metal nanofillers, intrinsic conductive polymers, carbon materials, and other methods to construct conductive paths, stretchable conductors can be effectively prepared by elastomeric nanofibers, showing great potential in the field of flexible sensors. This perspective briefly introduces the representative preparations of conductive thermoplastic polyurethane, nylon, and hydrogel nanofibers by electrospinning and the application of integrated electronic devices in biological signal detection. The main challenge is to unify the stretchability and conductivity of the fiber structure.

Іхнофосилії з відкладів бучацької світи (лютецький ярус, еоцен) Луганщини та їхнє палеогеографічне значення

Eleven Fodinichnia, Pascichnia, and Domichnia ichnotaxa (Apectoichnus longissimus (Kelly et Bromley, 1984), cf.Conichnus isp., Gastrochaenolites isp., Gnathichnus isp., Macaronichnus segregatis Clifton et Thompson, 1978,Ophiomorpha nodosa Lundgren, 1891,Palaeophycus isp., cf.Rosselia isp.,Skolithos linearis (Haldeman, 1840),Spongeliomorpha isp., and Thalassinoides isp.) were identified from seven sections of shallow marine sediments of the Buchak Formation (Lutetian, middle Eocene) located in Luhansk Oblast, eastern Ukraine. Traces of bioerosion on the contact surface between the Upper Cretaceous marls and the Buchak Formation indicate the development of the Trypanites Ichnofacies in conditions of high water activity with almost absent sedimentation. Most of the sediments of the Buchak Formation in the study area was formed in the conditions of the Skolithos Ichnofacies, namely in littoral environments with significant water activity, to resist which organisms were forced to build burrow systems. Some time intervals were also characterized by a decrease in the activity of the water, during which the sands of the littoral and probably sublittoral zones were colonized by the trace-makers of Macaronichnus segregatis burrows. In places of mass accumulation of wood, the Teredolites Ichnofacies is recognized, which is characterized by the development of teredenid bivalves specializing in feeding on wood. The contact surface of the Buchak and Kyiv formations is a firmground with the Glossifungites Ichnofacies developed on its surface and under it, which was already functioning during the accumulation of Kyiv Formation sediments. This ichnofacies was characterized by high water activity and the presence of organisms capable of bioturbating relatively dense substrates. The origin of massifs and blocks of quartzite-like sandstones among the sands of the Buchak Formation of Luhansk Oblast and many other sections of eastern and north-eastern Ukraine is not fully understood, but their hydrothermal genesis is most likely. The obtained data are of great importance for the reconstruction of the depositional environment of the middle Eocene sediments in eastern Ukraine.

Fabrication of praseodymium-doped ceria (PDC) films by slurry spin-coating technique and its structural, morphological and optical properties

The current study is on the fabrication of PDC films prepared by slurry spin-coating technique for photoluminescence activity. At lower spin rates (1000 rpm), thicker and uniform PDC films were obtained. The structural evolution of the sintered PDC films on a dense alumina substrate was studied using Grazing Incidence X-ray diffraction (GIXRD) and Raman Spectroscopy. Crystallite size, microstrain, and dislocation density values remain almost the same with the increase in the coating cycles. The A568/A463 ratio for 3, 5, and 10 coating cycles are 0.52, 0.49, and 0.61, respectively. Surface roughness studies of PDC films using a 3D Noncontact Profilometer. The mean surface roughness values are 12.55, 13.74, and 22.25 μm for the 3rd,5th, and 10th coating cycles, respectively. Microstructure observation by Field Emission Scanning Electron Microscope (FE-SEM). The average thickness of the films for the 3rd, 5th, and 10th coating cycles are 50.93, 41.64, and 109.95 μm, respectively. The PDC films obtained on a dense alumina substrate were porous. FE-SEM micrographs showed a particle aggregation of several irregular and smaller grains, indicating the sintering activity of PDC films. Optical properties were studied using ultraviolet-visible (UV–Vis) absorption spectra and photoluminescence spectra (PLS). The band gap values slightly increased with the increase in the coating cycles. A decrease in PL intensity with an increase in the coating cycle is related to higher oxygen vacancy concentration. PDC films fabricated by the slurry spin-coating technique can be successfully used for optoelectronic applications.

Exploring the Bottom-Up Growth of Anisotropic Gold Nanoparticles from Substrate-Bound Seeds in Microfluidic Reactors.

We developed an unconventional seed-mediated in situ synthetic method, whereby gold nanostars are formed directly on the internal walls of microfluidic reactors. The dense plasmonic substrate coatings were grown in microfluidic channels with different geometries to elucidate the impacts of flow rate and profile on reagent consumption, product morphology, and density. Nanostar growth was found to occur in the flow-limited regime and our results highlight the possibility of creating shape gradients or incorporating multiple morphologies in the same microreactor, which is challenging to achieve with traditional self-assembly. The plasmonic-microfluidic platforms developed herein have implications for a broad range of applications, including cell culture/sorting, catalysis, sensing, and drug/gene delivery.

Superior Electrochemical Performance of a Ce0.8Gd0.2O2-δ/Zr0.8Sc0.2O2-δ Thin Bilayer-Protected Gadolinium-Doped Ceria Electrolyte in Intermediate-Temperature Solid Oxide Fuel Cells.

To improve the performance of the Ce0.8Gd0.2O2-δ (GDC) electrolyte in a solid oxide fuel cell, it is necessary to block the electronic conduction due to Ce3+/Ce4+ transitions occurring at elevated temperatures. In this work, a GDC/ScSZ double layer consisting of 50 nm GDC and 100 nm Zr0.8Sc0.2O2-δ (ScSZ) thin films were deposited on a dense GDC substrate by the pulsed laser deposition (PLD) technology. The effectiveness of the double barrier layer in blocking the electronic conduction of the GDC electrolyte was investigated. The results showed that the ionic conductivity of GDC/ScSZ-GDC was slightly lower than that of GDC in the temperature range of 550-750 °C, but the difference gradually decreased with the increase in temperature. At 750 °C, the conductivity of GDC/ScSZ-GDC was 1.54 × 10-2 S·cm-1, which was almost the same as that of GDC. The electronic conductivity of GDC/ScSZ-GDC was 1.28 × 10-4 S·cm-1, which was lower than that of GDC. The conductivity results showed that the ScSZ barrier layer can reduce electron transfer effectively. More obviously, the open-circuit voltage and the peak power density of the (NiO-GDC)|GDC/ScSZ-GDC|(LSCF-GDC) cell were higher than those of the (NiO-GDC)|GDC|(LSCF-GDC) cell in the temperature range of 550-750 °C. The superior performance of the GDC/ScSZ-GDC electrolyte is attributed to the ScSZ thin layer, which is effective in blocking the electronic conduction of the GDC electrolyte.

A dense SERS substrate of the AgNPs@GO compound film for detecting homocysteine molecules.

This study focuses on the development of a highly sensitive surface-enhanced Raman scattering (SERS) sensor for detecting homocysteine (Hcy) molecules. The Hcy sensor was created by depositing silver nanoparticles (AgNPs) onto the surface of graphene oxide (GO) film to form a dense AgNPs@GO composite film. The AgNPs on the composite film interacted with sulfur atoms (S) of Hcy molecules to form Ag-S bonds, which boosted the chemisorption of Hcy molecules and enabled them to be specifically recognized. The SERS sensor exhibited a maximum enhancement factor of up to 1.1 × 104, with a reliable linear response range from 1 to 60 ng mL-1. The limit of detection (LOD) for Hcy molecules was as low as 1.1 × 10-9 M. Moreover, Hcy molecules were successfully distinguished in a mixed solution of γ-aminobutyric acid and Hcy molecules. In this study, a simple preparation process of SERS substrate and a novel detection method for Hcy molecules provided a new pathway for the rapid and effective detection of Hcy molecules in the food and biomedicine fields.