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ZnO–Au@ZIF-8 core–shell heterostructures were prepared by ZIF-8 encapsulation of sacrificial ZnO–Au nanorods. Because of the catalytic activity of the Au nanoparticles and the sieving effects of the ZIF-8, the ZnO–Au@ZIF-8 heterostructures showed an outstanding response of 1.8 to 5 ppb NO2, and exhibited higher selectivity, stability, anti-humidity and fast response and recovery properties. The combination of the gas-selective catalytic activity of noble metals with the MOF filter used in this work can be easily extended to synthesize other types of MOS@MOF sensors, opening a new avenue for the detection of hazardous gases. [ABSTRACT FROM AUTHOR]

Rational construction of low-cost and high-performance electrocatalysts for water splitting is crucial for the advancement of renewable hydrogen fuel. Hybridizing heterojunctions or noble metals is one typical strategy used to boost the electrocatalytic performance for either the oxygen evolution reaction (OER) or hydrogen evolution reaction (HER). Here, low-content CeOx (3.74 wt%) is introduced into Ni3Fe nanoparticle-encapsulated carbon nanotubes (Ni3Fe@CNTs/CeOx), with both the OER and HER activities boosted, as a bifunctional electrocatalyst for overall water splitting. The composite is derived by pyrolyzing a mixture of melamine/ternary NiFeCe-layered double hydroxide. The composite electrocatalyst requires low overpotentials of 195 and 125 mV at 10 mA cm−2 in 1.0 M KOH, respectively, which are superior to those of Ni3Fe@CNTs/NF (313 and 139 mV) and CeOx/NF (345 and 129 mV), and in particular, OER overpotentials of 320 and 370 mV at 50 and 100 mA cm−2, respectively. Moreover, the composite-assembled electrolyzer for overall water splitting requires a current density of 10 mA cm−2 at a decent cell voltage of 1.641 V. Furthermore, the enhancement is elucidated by the synergistic effect: the dual role of CeOx in boosting the OER and HER, the highly conductive carbonaceous CNTs, large electrochemically active surface area and low charge-transfer resistance. The results can offer an effective route for designing and preparing low-cost and high-efficiency electrocatalysts for electrocatalytic water splitting. [ABSTRACT FROM AUTHOR]

High‐performance thermal interface materials are in increasing demand because of the problems of dissipating heat from high‐power computing devices. To solve this problem, this study proposes a method of microstructural design through uniaxial compression of graphene foam along the out‐of‐plane direction. The thermal conductivity of the composites with graphene foam shows an anisotropic growth along the direction of the compressive strain. The in‐plane thermal conductivity increases significantly from 0.189 to 1.669 W m−1 K−1 at an extremely low filler content of 2.24 vol%, whereas the out‐of‐plane thermal conductivity increases slightly to 0.303 W m−1 K−1. Moreover, the samples exhibit outstanding in‐plane thermal conductivity enhanced efficiency, which reaches 415.19% at a 1.29 vol% graphene content. The mechanism of anisotropic thermal conductivity enhancement is revealed by constructing a theoretical model based on a geometrical unit cell simplified from the morphology of graphene foam. This uniaxial compression method of a 3 structure provides a novel direction for improving the thermal conductivity of polymeric matrix composites more controllably. [ABSTRACT FROM AUTHOR]

The study was focussed on the inhibitory mechanism associated with the ability of an endophytic bacterium - Bacillus altitudinis Q7, obtained from Ginkgo biloba, to inhibit the growth of Alternaria alternata in vitro. A fungus, identified as Alternaria alternata was isolated from the rotten part of an apple. One of the endophytes was identified as Bacillus altitudinis Q7. Effect of Bacillus altitudinis Q7 on Alternaria alternata was characterized by measuring membrane permeability and lipid peroxidation. Antioxidant enzymes in Alternaria alternata were determined before and after exposure to Bacillus altitudinis Q7. Results indicated that cell membranes in Alternaria alternata were damaged, lipid peroxidation was enhanced, and superoxide dismutase, peroxidase, and polyphenol oxidase were significantly inhibited. Content of lipopeptides produced by Bacillus altitudinis Q7 was higher than other metabolites. The FTIR spectra revealed that the prepared antibacterial lipopeptides is a cyclic lipopeptides. The effect of lipopeptides produced by Bacillus altitudinis Q7 at 2 mg/mL against Alternaria alternata in vitro reached 83.2%. The lipopeptide-treated group showed the same trend as Q7 fermentation broth in inhibition mode of action. Moreover, the utilization of proteins and sugars during culturing of Alternaria alternata decreased when adding lipopeptides to the growth medium. Bacillus altitudinis Q7 from Ginkgo biloba significantly inhibited the growth of Alternaria alternata and is a very promising biocontrol strain against Alternaria alternata. The study of endophytic bacteria and its metabolites is being done to identify biological control alternatives. The results provide a theoretical basis for understanding their antagonistic properties. [ABSTRACT FROM AUTHOR]

We report magnetic alignment of single-crystalline microdiamonds with aid of superparamagnetic magnetite in polymeric composites and their material properties. The silicone composite containing aligned microdiamonds shows interesting properties in alignment direction, including enhancement of thermal conductivity, 250% higher than that of randomly dispersed counterpart at a low loading of 5.1 vol%. Composites with aligned diamond exhibited enhanced thermal conductivity and electrical insulation compared with matrix, and are attractive for application as thermal interface materials in the semiconductor industry, though the introduction of magnetite had part of negative effect on electrical resistivity of composites. A two-level model that accounts first-order interaction between particles to calculate effective thermal conductivity of composites with aligned microdiamonds, is found to fit accurately absolute value and tendency of thermal conductivity for composites with aligned particles. Utilizing the modelling procedure, the volume fraction of microdiamonds within chains is 0.3, which is smaller than 0.698 predicted for ideal body-centered-tetragonal arrangement of particles. This suggested that thermal conductivity of composites can be enhanced further by improving microstructures within particle chains. [ABSTRACT FROM AUTHOR]

The exploration of novel NO 2 sensors with high performance is of great importance for air quality monitoring and human health. In this work, Au-doped ZnO@ZIF-7 core-shell nanorod arrays were fabricated for high-performance NO 2 detection. Due to the spill-over effects of Au nanoparticles, gas enriching and molecular sieving effects provided by ZIF-7 membranes, the ZnO-Au@ZIF-7 sensor affords highly sensitive and selective detection of NO 2. The heterostructured ZnO-Au@ZIF-7 allows for ppb-level detection of NO 2 (Response = 1.7–5 ppb) with excellent repeatability and provides improved selectivity, anti-humidity capacity, and long-term stability compared with bare ZnO, Au-doped ZnO or ZnO@ZIF-7 core-shell nanorod arrays. According to the calculation of density functional theory (DFT), the ZnO-Au@ZIF-7 sensor renders higher adsorption energy towards NO 2 molecules compared with the aforementioned other materials, which also explains its outstanding sensing performances. We believe our approach that combines noble metals doped semiconductor metal oxides (SMOs) and MOF filtration membranes can be further extended to numerous new heterostructured SMO@MOF materials, which opens venues to the development of advanced chemiresistive gas sensors. • Facile fabrication of Au-doped ZnO@ZIF-7 core-shell nanorod arrays. • ZIF-7 membranes effectively enrich NO 2 and filtrate larger gas molecules. • Ultra-low limit of detection (≤5 ppb) of NO 2. • Excellent selectivity, improved anti-humidity capability and long-term stability. [ABSTRACT FROM AUTHOR]

The mechanism of this anisotropy is revealed and the effective thermal conductivity (ETC) prediction model is established, broadening the application scope of ETC prediction models in 3D thermal conductive fillers. B Front Cover b : A novel structural optimization of graphene foam through uniaxial compression is proposed in article 2200373 by Jiaqi Zhu and co-workers, and leads to controllable and superior anisotropic thermal conductivity. [Extracted from the article]

Fracture healing is regulated by proinflammatory mediators such as tumor necrosis factor-α (TNF-α), which poses influence on the balance between bone formation and remodeling. And the diabetes is thought to contribute to the delayed diabetic fracture healing. In the present study, we examined the promotion to proinflammatory cytokines and chemokines in type 2 diabetes mellitus (T2DM) patients with bone fractures, and then evaluated the promotion to TNF-α by the high glucose treatment in human osteoblast-like MG-63 cells and the regulatory role of the promoted TNF-α on the MG-63 cell apoptosis. It was demonstrated that there were significantly-upregulated high-sensitivity C-reactive protein (hsCRP) TNF-α, IL-1β, IL-6, IFN-γ-inducible protein 10 (IP-10) and RANTES in T2DM patients with bone fracture. And the promotion to TNF-α and IL-1β was confirmed in vitro in both mRNA and protein levels in high glucose-treated MG-63 cells. And either TNF-α or high glucose reduced the viability of MG-63 cells, promoted apoptosis and upregulated apoptosis-associated markers, such as released cytochrome c, cleaved caspase 3 and lyzed PARP. Moreover, there was a synergistic effect between TNF-α and high glucose. The viability reduction and the apoptosis induction of MG-63 cells were significantly higher in the group with both TNF-α and high glucose treatments, than in the group with singular TNF-α treatment. In conclusion, our study demonstrated that proinflammatory cytokines and chemokines were promoted in T2DM patients with bone fracture or in osteoblasts by the high glucose stimulation. TNF-α and high glucose synergistically reduced the viability and induced the apoptosis in the osteoblast-like MG-63 cells in vitro . It implies the significant regulatory role of TNF-α in the delayed fracture healing in T2DM. [ABSTRACT FROM AUTHOR]

Novel power dividers based on Gysel architecture with tunable power dividing ratio (TPDR), tunable central frequency (TCF), perfect port matching and isolation are proposed. The regulatory mechanism of traditional Gysel Power Divider (GPD) is studied, and a novel electrical tunable method is presented to tune the power divider ratio by only the electrical length of the GPD section, which simplifies the design of tunable power dividers. Tunable T -type networks are used to tune the power dividing ratio and central frequency by tuning this electrical length parameter, and the TPDR range can be pre-defined by setting the characteristic impedance of the transmission lines in the tunable power divider. The tunable mechanism of the circuits was theoretical studied. Two power dividers operating at 950 MHz with TPDR of 0.3:1 ∼ 35.9:1 and 1.1:1 ∼ 35.4:1, and a GPD with TCF in 1.1 GHz ∼ 1.6 GHz were designed and fabricated. All the measured results are in good agreement with the simulation. [ABSTRACT FROM AUTHOR]

• A 3D bi-network of GF and NDs in composites has been designed and fabricated. • Composites with a bi-network structure exhibited higher thermal conductivity. • The thermal conductivity enhancement efficiency can be maintained up to 74.33%. • FEA was carried out to confirm the heat transfer mechanism of the bi-networks. As thermal interface materials, polymers are limited by its low thermal conductivity. In this work, a three-dimensional bi-network structure consisting of chemical vapor deposition graphene foam and close-stacked nanodiamonds was constructed in epoxy matrix via a template method. The obtained composites exhibit interesting properties: significant thermal conductivity enhanced efficiency per unit of fillers (74.33%) based on pure epoxy matrix, and excellent electrical conductivity (0.256 S/cm) compared with epoxy matrix (4.58exp-14 S/cm). Finite Element Analysis based on the design of the dual networks was carried out to confirm the heat transfer mechanism, and it is proved that composites with GF/ND bi-network have a lower temperature gradient. That provides a novel insight of improvement method for thermal conductivity by construction of a three-dimension bi-network structure. [ABSTRACT FROM AUTHOR]

Samples collected from the surface/subsurface of C-type asteroid 162173 Ryugu by the Hayabusa2 mission were nondestructively analyzed in three dimensions (3D). Seventy-three small particles (approximately 10–180 µm in size) were observed using X-ray nanotomography, with an effective spatial resolution of approximately 200 nm. Detailed descriptions of these samples in terms of mineralogy, petrology, and variations among particles were reported. The 57 most common particles consisted of a phyllosilicate matrix containing mineral grains, mainly magnetite, pyrrhotite, dolomite and apatite. The remaining particles were mostly monomineralic particles (pyrrhotite, dolomite, breunnerite, apatite, and Mg-Na phosphate) with two unique particles (calcite in a Al 2 Si 2 O 5 (OH) 4 matrix, and CaCO 3 , phyllosilicate, and tochilinite-chronstedtite inclusions in a carbonaceous material matrix). The results confirmed that the samples correspond to Ivuna-type carbonaceous chondrites (CI chondrites) or related materials. Many small inclusions of voids and carbonaceous materials were detected in pyrrhotite, dolomite, breunnerite, and apatite. However, no fluid inclusions were observed, except for those in pyrrhotite that have already been reported. Magnetite exhibited a wide variety of morphologies, from irregular shapes (spherulites, framboids, plaquettes, and whiskers) to euhedral shapes (equants, rods, and cubes), along with transitional shapes. In contrast, the other minerals exhibit predominantly euhedral shapes (pyrrhotite: pseudo-hexagonal plates, dolomite: flattened rhombohedrons, breunnerite: largely flattened rhombohedrons, and apatite: hexagonal prisms) or aggregates of faceted crystals, except for Mg-Na phosphate. The matrices were heterogeneous with variable phyllosilicate particle sizes, Mg/Fe ratios, density (1.7 ± 0.2 g/cm3), nanoporosities (36 ± 9 %), and abundances of nanograins of Fe(-Ni) sulfides. The macroporosity of the particles was estimated as 12 ± 4 %. The observed textural relationships among the minerals suggest a precipitation sequence of: magnetite (spherulite → plaquette/framboid → rod/equant) → pyrrhotite (pentlandite → pyrrhotite) → apatite → dolomite → breunnerite → coarse phyllosilicates. Fe-bearing olivine (or low-Ca pyroxene) might have precipitated later than dolomite, indicating a high Mg activity in the aqueous solution. This precipitation sequence corresponds to a transition from irregular crystal forms (as seen in some magnetite) to regular forms of euhedral crystals (observed in some magnetite and other minerals). Based on the precipitation sequence and mineral morphologies, together with previously reported observations, a model for aqueous alteration in the Ryugu parent body was proposed as follows: CO 2 -H 2 O ice, amorphous silicates (GEMS-like material), and some minerals (mostly metal, sulfides, and anhydrous silicates) accumulated to form the parent body of Ryugu. Amorphous silicates and Fe-Ni metal quickly dissolved into the melted ice to form a highly supersaturated aqueous solution. Poorly-crystalized phyllosilicate and spherulitic magnetite precipitated first, followed by plaquette/framboidal magnetites with decreasing degree of supersaturation due to precipitation. Pseudo-hexagonal pyrrhotite plates were formed by dissolution and reprecipitation under relatively low supersaturation. Subsequently, apatite, dolomite, and breunnerite precipitated in this order in response to decreasing supersaturation. [ABSTRACT FROM AUTHOR]

Expression of miR-671 was reported to be downregulated in articular cartilage of patients with OA compared to healthy individuals, indicating it may serve as potential biomarker for OA. However, the mechanism by which miR-671 regulates the progression of OA remains unclear. Here, we aimed to investigate the role of miR-671 in cartilage from patients with OA. The expression of miR-671 and inflammation mediators in cartilage from patients with OA was analyzed by RT-PCR. In vitro , chondrocytes CHON-001 were stimulated with IL-1β for 24 h for OA model establishment. Protein expression of MMP-13, aggrecan, and collagen II was measured by western blot. In vivo , the severity of OA in mice was determined by histological analysis. We found that the level of miR-671 was downregulated in OA tissues, plasma and IL-1β treated CHON-001 cells, compared with control. MiR-671 mimics ameliorated IL-1β-induced proliferation inhibition and apoptosis stimulation, as well as decreased protein levels of collagen II and aggrecan in CHON-001 cells. In vivo study showed miR-671 mimics alleviated the progression of OA in mice. These results indicated miR-671 play an important role during the pathogenesis of OA. Therefore, miR-671 may serve as a potential therapeutic target for the treatment of OA. [ABSTRACT FROM AUTHOR]

In deep-towed multi-channel seismic systems, nonuniform mass distribution of seismic arrays results in a "W" shape, negatively impacting the exploration resolution. High towing speeds or use of large drogues can straighten the arrays; however, these approaches adversely affect the towing depth and maximum cable tension. Therefore, this study performed system optimization for drogue dimensions, towing speed, and towing cable length by employing an efficient surrogate model-based method. A surrogate model of the drogue that incorporates dimensional variation, along with another surrogate model that merely expresses the relationship between the drag forces and towed-vehicle motions, were used. These surrogate models were connected via nonuniform arrays modeled by an efficient quasi-static iteration method validated using the absolute nodal coordinate formulation. Finally, the drogue dimensions, towing speed, and towing cable length were optimized under constraints of limited towing depth and cable tension; the maximum vertical deviation of array shape was significantly reduced (from 3.0 m to 0.5 m). The quasi-static iteration and surrogate model-based approach affords an efficient means of optimizing the device dimensions and towing operations for marine towed systems. • An efficient quasi-static iteration method is proposed to determine nonuniform array shapes. • Surrogate models are generated to optimize drogue dimensions and towing operations. • The maximum vertical deviation of the array shape is < 0.5 m for 150-m long arrays. • System optimization affords quantized information for towing operations. [ABSTRACT FROM AUTHOR]

In this work, we demonstrate a novel structure that can generate extraordinary optical transmission with a silicon hemisphere placed on a conventional bull's eye structure. There is a single subwavelength aperture surrounded by concentric periodic grooves on a substrate. The extraordinary optical transmission in this work is realized by the coupling of the surface plasmon polaritons in the periodic grooves and the localized electromagnetic field generated by the Mie resonance in the silicon hemisphere. The maximum normalized-to-area transmission peak can reach up to 662 with a decreasing device area and size. The electromagnetic field distribution at different geometry parameters is analyzed to clarify the mechanisms of the work in this paper. Additionally, the use of dielectric material in the aperture can avoid ohmic losses of metal material compared with the conventional one, which may suggest that a wider range of bull's-eye-structure applications is possible. [ABSTRACT FROM AUTHOR]

Sleep duration suggests some association with osteoporosis and cardiometabolic diseases, but it is unknown if these associations are causal or confounded. In this two-sample Mendelian randomization (MR) study, we included the largest genome-wide association studies (GWASs) associated with sleep duration and the outcome measures of osteoporosis and cardiometabolic diseases. Finally, 25 single nucleotide polymorphisms (SNPs) associated with short sleep duration and 7 SNPs associated with long sleep duration obtained the genome-wide significance (P < 5 × 10 − 8 ) and were used as instrumental variables. Genetic predisposition to short sleep duration was strongly associated with increased risk of coronary artery disease (beta-estimate: 0.199, 95% confidence interval CI: 0.081 to 0.317, standard error SE :0.060, P value = 0.001) and heart failure (beta-estimate: 0.145, 95% CI: 0.025 to 0.264, SE :0.061, P value = 0.017), which were both confirmed by the sensitivity analyses. Both short and long sleep duration may reduce the estimated bone mineral density (eBMD, beta-estimate: -0.086, 95% CI: -0.141 to -0.031, SE :0.028, P value = 0.002 for short sleep duration; beta-estimate: -0.080, 95% CI: -0.120 to -0.041, SE :0.020, P value < 0.0001 for long sleep duration). There was limited evidence of associations between sleep duration and fracture, type 2 diabetes, atrial fibrillation, fasting glucose, fasting insulin, or HbA1c. This study provides robust evidence that short sleep duration is causally associated with high risk of coronary artery disease and heart failure and suggests that short sleep duration should be avoided to prevent these two cardiovascular diseases. Short and long sleep duration show some MR association with reduced eBMD, which indicates that both short and long sleep duration may be prevented to reduce the incidence of osteoporosis. [ABSTRACT FROM AUTHOR]

The study examined the potential nutritive value of rice protein (RP) through Maillard reaction. Structures and properties of synthetic conjugates of RP and exopolysaccharide (EPS) from Arthrobacter ps‐5 were investigated systematically. Fluorescence characteristics and high molecular weight compounds appeared in Maillard reaction products (MRPs). Moreover, EPS or its degradation products in the form of covalent bond cross‐linked with RP were identified, where –NH2 disappeared and C=O, C=N and C–N increased. Determination of free –SH residues suggested mutual conversion between disulfide bonds and sulfhydryl groups occurred during Maillard reaction. HPLC analysis identified conjugates with different molecular weight, where melanoprotein was formed by covalent bonds. As RP conjugated with EPS, the molecules spread out and changed the spatial structure. Functional properties of MRPs, including solubility, foaming activity, emulsifying ability and resistance to oxidation, were greatly improved. The study has discovered an efficient method for increasing the application value of plant protein. [ABSTRACT FROM AUTHOR]

Oxygen-terminated type IIa (OT-IIa) diamond with oxygen suspended in the form of a ketone bond (C O) was synthesized via acid treatment. The Fermi level at 3.23 eV below the conduction band minimum for the OT-IIa diamond surface was measured experimentally, while that at 0.97 eV for the bulk was calculated theoretically. An acceptor model of the surface states was developed, employed, and combined with an upward-bending band diagram to compensate this energetic band difference between the surface and bulk of OT-IIa diamond. A Schottky barrier height of 3.15 eV between gold and the OT-IIa diamond was also measured. In addition, we also inferred the downward-bending band diagram for the surface of oxygen-terminated p-type diamond doped with boron. This work complements the semiconductor theory concerning diamond and will be helpful to analyze and improve the performance of devices based on oxygen-terminated diamond. Image 1 [ABSTRACT FROM AUTHOR]

Background: Osteonecrosis of the femoral head (ONFH) is a refractory disease which frequently occurs in young and middle‐aged people. Recent studies indicated that MMP‐14 played an important role in the development of chondrocytes, metabolism of osteoblasts as well as fate decision of hypertrophic chondrocytes. The aim of this study was to investigate the association between polymorphisms of MMP‐14 and steroid‐induced osteonecrosis of the femoral head in the Chinese population. Methods: We selected 7 SNPs (rs3751488, rs1003349, rs1042703, rs2236302, rs1042704, rs2236303, and rs2236304) on gene MMP‐14. Odds ratios (ORs) and 95% confidence intervals (CIs) were estimated using the chi‐squared test, genetic model analysis, haplotype analysis, and stratification analysis. Results: We discovered that the genotype "G/G" of rs2236302 was associated with ONFH risk in the MMP‐14 in the codominant model (OR = 8.62, 95% CI = 1.07–69.46, p = 0.038) and recessive model (OR = 8.86, 95% CI = 1.10–71.31, p = 0.013). Conclusions: We have confirmed that the susceptive SNPs (rs2236302) of MMP‐14 from the MMPs/TIMPs system exhibit a significant association with increased risk of steroid‐induced ONFH in the population of northern China. The aim of this study was to investigate the association between polymorphisms of MMP‐14 and steroid‐induced osteonecrosis of the femoral head in the Chinese population. We have confirmed that the susceptive SNPs (rs2236302) of MMP‐14 from the MMPs/TIMPs system exhibit a significant association with increased risk of steroid‐induced ONFH in the population of northern China. [ABSTRACT FROM AUTHOR]

It has been widely accepted that conversion between negatively charged nitrogen-vacancy (NV−) center and neutral nitrogen-vacancy (NV0) center can be realized with the Fermi level crossing the transition level corresponding to the ground state of NV−. In this study, a suppressing effect was observed in the emission of NV− center; however, emission of NV0 center was not observed to be increasing as expected and was stable when lowering of the Fermi level was induced by a Schottky junction between gold and oxygen-terminated diamond containing NV centers. The relationship between the thickness of the depletion layer as well as that of the suppression layer, appearing when the Fermi level shifted below the ground state level of NV−, and the donor concentration was derived. Moreover, a model based on the assumption that an intermediate transition level (nonfluorescence state) existed between the ground state energy levels of NV− and NV0, was proposed to explain why suppressed NV− did not convert to NV0. The results of this study will aid in further understanding of the characteristics of NV centers. In addition, a Schottky junction can be developed to determine the charge state of unknown color centers and facilitate study of defects in diamonds. Image 1 [ABSTRACT FROM AUTHOR]

• An interdigital-electrode structured UV detector with back-contact is designed and fabricated on single crystal diamond. • Higher responsivity and higher detectivity were observed when the back electrode contact was activated. • The mechanism for the improved performance has been revealed by UV-vis transmittance test and electric field simulation. An interdigital electrode of 200-nm thickness, 160-μm spacing, and 160-μm width was fabricated on one side of a diamond fabricated by chemical vapor deposition. A gold contact of 200-nm thickness was deposited on the back side of the diamond. The back contact and one half of the interdigital electrode were connected by a switch. Higher responsivity and higher detectivity were observed when the back electrode contact was activated. The results of electrical field simulation showed that a stronger electrical field formed over the diamond region in the device with the back electrode than in that without the back electrode. This indicated that the detector performance improvement could be attributed to the higher carrier collection efficiency achieved with the back electrode, particularly under ultraviolet (UV) light at certain wavelengths, which have longer attenuation lengths in diamond. This structure could also be applied to UV detectors based on other wide-band-gap semiconductors. [ABSTRACT FROM AUTHOR]

A UV detector based on a planar quadrant electrode structure with a 100-μm isolating cross-gap deposited on chemical vapor deposition diamond was fabricated. An asymmetrical behavior was observed for the amplitude of photocurrent when in forward and reverse bias. A linear relationship between the sum of the photocurrents at biases U and −U, and the light spot position was also observed. The aim of this study is to clarify the mechanism underlying this asymmetrical behavior and exhibit its potential application based on this behavior. A mechanism involving lowering of the contact barrier height between gold and i-diamond by carrier generation upon UV illumination was adopted to account for the photocurrent behavior and confirmed when an opposite asymmetrical photocurrent behavior was observed in other samples. In addition, position-sensitive detection performance, based on this asymmetrical photocurrent behavior, was preliminarily studied. The results exhibited the potential for application as a position-sensitive detector. [ABSTRACT FROM AUTHOR]

A highly selective anisotropic etching method for single-crystal diamond was investigated. After a thin film of Fe was deposited on the diamond surface, it was processed in H plasma activated by microwave plasma-assisted-chemical vapor deposition (MPCVD). Spurred by the high catalytic activity of Fe, the diamond was easily etched, with masked areas (i.e., with no Fe deposition) remaining smooth or barely damaged. The etch rate was 180 nm min −1 . This method provides a simple and alternative way for diamond processing and patterning. [ABSTRACT FROM AUTHOR]

Diamond micro powders have been synthesized by chemical vapor deposition via etching a graphite substrate in hydrogen microwave plasma, without a hydrocarbon (methane) gas addition. The graphite temperature, varying from 700 to 1000 °C, was found to significantly affect the diamond nucleation and growth, the growth rate of the diamond particles increasing from 2.4 to ≈ 4 μm/h with the temperature. The diamond powders had a better crystalline quality at the substrate temperature of 900 °C. Because of low adhesion of the deposited grit to the substrate the particles can be collected easily and mechanically disaggregated. The average size of ≈ 12 μm of the dispersed particles grown for 5 h, was determined with a laser particle size analyzer, while the maximum grain size estimated with electron microscopy, varied between 12 and ≈ 20 μm. The particle's surface exhibited many micro-pyramids with sharp tips, that could be beneficial for abrasive applications. X-ray diffraction and Raman spectroscopy revealed high purity and quality of the diamond powders. [ABSTRACT FROM AUTHOR]

An ultraviolet (UV) detector on single crystal chemical vapor deposition (CVD) diamond with three-dimensional (3D) metal electrodes, is designed, and fabricated with the aim to improve collection efficiency of photo-induced carriers. Interdigitated Ti/Au electrodes were formed within 10 μm deep groove etched in diamond to ensure a more uniform field pattern in the diamond bulk. In the preliminary tests the groove-shaped 3D device performance was compared to a detector with a conventional planar structure on the same material at applied electric field of 1 V/μm. It is found that the responsivity of the 3D electrode structure in the spectral range of 220–280 nm is up to 50% higher than that for the planar structure. [ABSTRACT FROM AUTHOR]

• A PDMS elastomer based on imine groups is successfully prepared using Schiff base reaction. • The elastomer features an outstanding optical transmittance more than 80% in visible region. • The elastomer exhibits good mechanical strength, stretchability, and excellent self-healing properties. • The elastomer is recyclable and can be used as adhesives. Smart materials with self-healing properties that can heal themselves with restored mechanical performance are highly desired. Herein, a transparent healable PDMS (HPDMS) elastomer based on imine bonds is successfully prepared from amino-modified polydimethylsiloxane (PDMS) and 1,4-diformylbenzene (DFB) through a simple method. The concentration of DFB has a great effect on the gelation process. The elastomer features an outstanding optical transmittance (more than 80%) over the full visible light region. The results of TGA and DSC indicate that the HPDMS elastomer is highly flexible at room temperature and can be used in a wide temperature range. The presence of imine bonding and the formation of Schiff base linkages is proved by the FT-IR and Raman spectra. The reversible imine bond can promote the contact of the fracture surfaces and result in quick and repeatable self-healing without any external intervention such as heat or light. Furthermore, the elastomer exhibits excellent recyclability and reprocessability. Besides, the adhesion test reveals the potential of the elastomer in application as adhesives. We anticipate that this strategy can be employed to prepare a transparent PDMS elastomer with mechanical strength, stretchable, and excellent self-healing properties. [ABSTRACT FROM AUTHOR]