High-performance flexible p-type Ce-filled Fe3CoSb12 skutterudite thin film for medium-to-high-temperature applications.

P-type Fe3CoSb12-based skutterudite thin films are successfully fabricated, exhibiting high thermoelectric performance, stability, and flexibility at medium-to-high temperatures, based on preparing custom target materials and employing advanced pulsed laser deposition techniques to address the bonding challenge between the thin films and high-temperature flexible polyimide substrates. Through the optimization of fabrication processing and nominal doping concentration of Ce, the thin films show a power factor of >100 µW m-1 K-2 and a ZT close to 0.6 at 653 K. After >2000 bending cycle tests at a radius of 4 mm, only a 6 % change in resistivity can be observed. Additionally, the assembled p-type Fe3CoSb12-based flexible device exhibits a power density of 135.7 µW cm-2 under a temperature difference of 100 K with the hot side at 623 K. This work fills a gap in the realization of flexible thermoelectric devices in the medium-to-high-temperature range and holds significant practical application value.

Selective Oxidation of Glycerol to Lactic Acid Catalyzed by CuO/Activated Carbon and Reaction Kinetics.

Activated carbon-supported CuO catalysts were prepared by an ammonia evaporation method and applied to catalyze the selective oxidation of glycerol to lactic acid. The effects of CuO loadings on the structure and catalytic performance of the catalyst were investigated. Results showed that CuO could be dispersed uniformly on the surface of activated carbon, promoting the increase of the reaction rate and accelerating the glycerol conversion significantly. As CuO loadings increased, the rate of glycerol consumption and yield to lactic acid was increased. However, too high CuO loadings would destroy the original pore structure of activated carbon and aggravate the agglomeration of CuO, resulting in a decrease in the catalytic performance of the catalyst. The best catalytic performance was obtained over 10% CuO/AC when the reaction temperature was 190 °C and the reaction time was 5 h. At this point, the selectivity to lactic acid reached 92.61%. In addition, power-function type reaction kinetic equations were used to evaluate the effect of glycerol and NaOH concentrations and the reaction temperature on the oxidation of glycerol to lactic acid over 10% CuO/AC. The activation energy of the reaction is 134.39 kJ·mol-1, which is higher than that using single CuO as the catalyst. This indicates that CuO/AC is more temperature-sensitive than CuO and can probably achieve a higher lactic acid yield at high temperatures. At the same time, it is indicated that CuO supported on activated carbon can enhance the catalytic activity of CuO effectively.

Influence of Engineering Parameters on Fracture Vertical Propagation in Deep Shale Reservoir: A Numerical Study Based on FEM.

The geometry of hydraulic fractures in deep shale facies is significantly affected by the longitudinal inhomogeneity of rock physical properties and stresses. Numerous studies have been conducted on the influence of the longitudinal inhomogeneity of rocks on fracture morphology. However, there is still a lack of research that simultaneously considers the reservoir dip, bedding plane interface, and longitudinal inhomogeneity of the reservoir. To fill this gap, a three-dimensional (3D) numerical model of multireservoir hydraulic fracturing, which takes into account the bedding plane interface, was developed using the finite element method (FEM). The Drucker-Prager elastic-plasticity criterion was incorporated to accurately represent the plasticity of deep shale. The research revealed the influence of the formation dip angle on fracture morphology. Additionally, the perforation layer position and pump rate were optimized based on the actual geological parameters in North Jiangsu shale reservoir. The study findings indicate that reservoir fractures with a formation dip are easily detected by the interface. However, it is not necessarily true that the larger the formation dip, the easier it is for fluids to enter the interface. Fracturing from high-strength and stress reservoirs to lower reservoirs promotes the propagation of fracture height and the connectivity of multiple reservoirs. On the other hand, fractures initiated from low-strength and stress reservoirs tend to be confined to adjacent reservoirs more easily. The pump rate significantly affects the vertical propagation of fractures. At high interface strength, fractures with pump rate below 2.4 m3/min can only propagate at the perforation layer. The limited fracture height in shale reservoirs is likely due to substantial energy consumption by the fracturing fluid at the bedding plane interface. These studies offer theoretical guidance for understanding the vertical propagation of fractures in a deep multilayer reservoir.

Combining plasmon-enhanced fluorescence with Rayleigh surface acoustic waves to quantify Carcinoembryonic Antigen from human plasma.

To improve the direct quantification of Carcinoembryonic Antigen (CEA) from body fluids by immunofluorescence, a surface acoustic wave (SAW) based biosensor was developed combined with an optimized silver nanostructure at the sensing region. Fluorescence signal amplification is achieved by patterning silver nanostructures using the rapid thermal annealing (RTA) method. In addition, the problem of background noise interference from nonspecific binding in human plasma is addressed by Rayleigh wave streaming at the immunoassay region, which shows a reduction in the limit of detection. The results show that the silver nanostructures significantly increase the sensor sensitivity by 49.99-fold and lower the limit of detection of CEA in phosphate buffered saline (PBS) solution to 101.94 pg/mL. The limit of detection of CEA biomarker in human plasma was successfully brought down to 11.81 ng/mL by reducing background noise using Rayleigh SAW streaming. This allows for a point-of-need sensor system to be realized in various clinical biosensing applications.

Impurity Removal Leading to High-Performance CoSb3-Based Skutterudites with Synergistic Carrier Concentration Optimization and Thermal Conductivity Reduction.

Thermoelectric properties of CoSb3-based skutterudites are greatly determined by the removal of detrimental impurities, such as (Fe/Co)Sb2, (Fe/Co)Sb, and Sb. In this study, we use a facile temperature gradient zone melting (TGZM) method to synthesize high-performance CoSb3-based skutterudites by impurity removal. After removing metallic or semimetallic impurities (Fe/Co)Sb, (Fe/Co)Sb2, and Sb, the carrier concentration of TGZM-Ce0.75Fe3CoSb12 can be reduced to 1.21 × 1020 cm-3 and the electronic thermal conductivity dramatically reduced to 0.7 W m-1 K-1 at 693 K. Additionally, removing these impurities also effectively reduces the lattice thermal conductivity from 7.2 W m-1 K-1 of cast-Ce0.75Fe3CoSb12 to 1.02 W m-1 K-1 of TGZM-Ce0.75Fe3CoSb12 at 693 K. As a consequence, TGZM-Ce0.75Fe3CoSb12 approaches a high power factor of 11.7 µW cm-1 K-2 and low thermal conductivity of 1.72 W m-1 K-1 at 693 K, leading to a peak zT of 0.48 at 693 K, which is 10 times higher than that of cast-Ce0.75Fe3CoSb12. This study indicates that our facile TGZM method can effectively synthesize high-performance CoSb3-based skutterudites by impurity removal and set up a solid foundation for further development.

Ce Filling Limit and Its Influence on Thermoelectric Performance of Fe3CoSb12-Based Skutterudite Grown by a Temperature Gradient Zone Melting Method.

CoSb3-based skutterudite is a promising mid-temperature thermoelectric material. However, the high lattice thermal conductivity limits its further application. Filling is one of the most effective methods to reduce the lattice thermal conductivity. In this study, we investigate the Ce filling limit and its influence on thermoelectric properties of p-type Fe3CoSb12-based skutterudites grown by a temperature gradient zone melting (TGZM) method. Crystal structure and composition characterization suggests that a maximum filling fraction of Ce reaches 0.73 in a composition of Ce0.73Fe2.73Co1.18Sb12 prepared by the TGZM method. The Ce filling reduces the carrier concentration to 1.03 × 1020 cm-3 in the Ce1.25Fe3CoSb12, leading to an increased Seebeck coefficient. Density functional theory (DFT) calculation indicates that the Ce-filling introduces an impurity level near the Fermi level. Moreover, the rattling effect of the Ce fillers strengthens the short-wavelength phonon scattering and reduces the lattice thermal conductivity to 0.91 W m-1 K-1. These effects induce a maximum Seebeck coefficient of 168 µV K-1 and a lowest κ of 1.52 W m-1 K-1 at 693 K in the Ce1.25Fe3CoSb12, leading to a peak zT value of 0.65, which is 9 times higher than that of the unfilled Fe3CoSb12.

Regulating Water Reduction Kinetics on MoP Electrocatalysts Through Se Doping for Accelerated Alkaline Hydrogen Production.

Owing to its low cost, high conductivity, and chemical stability, Molybdenum phosphide (MoP) has great potential for electrochemically catalyzing the hydrogen evolution reaction (HER). Unfortunately, the development of high-activity MoP still remains a grand challenge in alkali-electrolyzers due to its sluggish water reduction kinetics. Here, we demonstrate a novel strategy for regulating the HER kinetics of the MoP nanowire cathode through partially substituting P atoms with Se dopants. In alkaline solutions, the Se-doped MoP (Se-MoP) nanowire cathode exhibits excellent HER performance with a greatly-decreased overpotential of ∼61 mV at 10 mA cm-2 and a Tafel slope of ∼63 mV dec-1, outperforming currently reported MoP-based electrocatalysts. Experimental and theoretical investigations reveal that Se doping not only facilitates the water dissociation on MoP, but also optimize the hydrogen adsorption free energy, eventually speeding up the sluggish alkaline HER kinetics. Therefore, this work paves a new path for designing MoP-based electrocatalyst with high HER performance in alkaline electrolyzers.

Effect of Ce doping on the structure-activity relationship of MoVO x composite metal oxides.

A series of Ce-doped MoVO x composite metal oxide catalysts were prepared by the rotary evaporation method. The effects of Ce doping ratio on the crystal phase composition, morphology and surface properties of the catalysts were investigated. The results show that the crystal phase composition of samples with different Ce doping content is also obviously different. When the doping amount is small, V0.95Mo0.97O5 is the main crystal phase, while MoO3 is dominant when the doping amount is large. The Ce-doped catalyst showed obvious rod-shaped morphology and its average single point pore diameter and the number of acidic sites increased. Compared to the un-doped MoVO x , the pore size of the sample synthesized at a Mo/Ce atomic ratio of 10/1 exhibited an increase of 41.11 nm. In addition, the effect of Ce doping on the catalytic performance of MoVO x was investigated with the selective oxidation of benzyl alcohol as a probe reaction. After doping, the MoVO x catalyst showed improved benzyl alcohol conversion and selectivity to benzaldehyde. At a Mo/Ce atomic ratio of 10/1, the conversion rate of benzyl alcohol reaches 83.26%, which is 64.56% higher than that without doping, and the highest product yield can reach 76.47%.

Single-Crystalline Mo-Nanowire-Mediated Directional Growth of High-Index-Faceted MoNi Electrocatalyst for Ultralong-Term Alkaline Hydrogen Evolution.

As appealing alternatives to noble-metal-based electrocatalysts for catalyzing hydrogen evolution reaction (HER) in alkali electrolyzers, earth-abundant MoNi-based catalysts have attracted intensive attention. Unfortunately, the exploration of MoNi-based electrocatalysts with superior intrinsic activity and ultralong-term stability still remains a grand challenge. Here, ultralong high-index faceted Mo@MoNi core-shell nanowires were topochemically synthesized through the thermal reduction of Mo@NiMoO4 core-shell nanowires, where single-crystalline Mo support facilitates the topological transformation of NiMoO4 into high-index faceted MoNi. When the as-achieved Mo@MoNi core-shell nanowire film serve as a free-standing cathode in alkaline solutions, it exhibit a remarkably decreased HER overpotential of 18 mV at 10 mA cm-2 and a Tafel slope of ∼33 mV dec-1, which are much lower than those for the state-of-the-art earth-abundant electrocatalysts and even commercial Pt/C. Experimental and theoretical investigations reveal that the exposed high-index (331) facets of MoNi can considerably reduce the energy barriers of initial water dissociation and subsequent hydrogen combination steps, which synergistically accelerates the sluggish alkaline HER kinetics. Significantly, after a 70-day HER operation, the overpotential of Mo@MoNi electrocatalysts at 10 mA cm-2 decreases by only 4 mV. Therefore, this work sheds a bright light on the rational design of high-performance HER electrocatalysts and their practical utilization for alkaline electrolyzers.

Facile sub-/supercritical water synthesis of nanoflake MoVTeNbO x -mixed metal oxides without post-heat treatment and their catalytic performance.

A fast and simple sub-/supercritical water synthesis method is presented in this work in which MoVTeNbO x -mixed metal oxides with various phase compositions and morphologies could be synthesized without post-heat treatment. It was demonstrated that the system temperature for synthesis had a significant influence on the physico-chemical properties of MoVTeNbO x . Higher temperatures were beneficial for the formation of a mixed crystalline phase containing TeVO4, Te3Mo2V2O17, Mo4O11 and TeO2, which are very different from the crystalline phases of conventional Mo-V-Te-Nb-mixed metal oxides. While at lower temperatures, Mo4O11 was replaced by Te. At high temperature, the as-prepared samples presented distinct nanoflake morphologies with an average size of 10-60 nm in width and exhibited excellent catalytic performances in the selective oxidation of propylene to acrylic acid. It is illustrated that the large specific surface area, presence of Mo4O11 and superficial Mo6+ and Te4+ ions are responsible for the high propylene conversion, while suitable acidic sites and superficial Nb5+ ions improved the selectivity to acrylic acid.

Design of a Portable Orthogonal Surface Acoustic Wave Sensor System for Simultaneous Sensing and Removal of Nonspecifically Bound Proteins.

One challenge for current surface acoustic wave (SAW) biosensors is reducing nonspecific adsorption. A device propagating Rayleigh and shear horizontal surface acoustic waves in orthogonal directions fabricated in ST quartz has the capability of achieving simultaneous detection and nonspecific binding (NSB) protein removal. Current measurement methods for a SAW sensor system based on this device require large-size and expensive equipment such as a vector network analyzer (VNA), signal generator, and frequency counter, which are not suitable for portable, especially point-of-care, applications. In this work, a portable platform based on a direct digital synthesizer (DDS) is investigated for the orthogonal SAW sensor, integrating signal synthesis, gain control, phase/amplitude measurement, and data processing in a small, portable electronic system. This prototype was verified for both stability and repeatability, and the results matched very well with VNA measurements. Finally, system performance in real-time sensing and NSB removal was evaluated.

Investigation of the In-Plane Mechanical Anisotropy of Magnesium Alloy AZ31B-O by VPSC⁻TDT Crystal Plasticity Model.

The in-plane mechanical anisotropy of magnesium alloy sheet, which significantly influences the design of the parts produced by Mg alloy sheets, is of great importance regarding its wide application. Though the stress-strain response and texture evolution have been intensively investigated, and the anisotropy of Mg alloy can be significantly substantiated by its R-value, which reveals the lateral response of a material other than the primary response. As a consequence, the conjunction of viscoplastic self-consistent model and twinning and detwinning scheme (VPSC-TDT) is employed to investigate the in-plane anisotropy of magnesium alloy AZ31B-O sheet. The loading cases include both tension and compression along different paths with respect to the processing direction of the sheet. It is revealed that the stress-strain relation, texture evolution, R-value, and involved deformation mechanisms are all loading path-dependent. The unique R-values of Mg alloys are interpreted with the aid of modeling behaviors of Mg single crystals. The results agree well with the corresponding experiments. It is found that the hexagonal close-packed (HCP) crystallographic structure, deformation twinning, and initial basal texture are responsible for the characteristic behavior of Mg alloys.

[Using of pre-hospital emergency resources by acute alcoholism patients in a hospital in Guangzhou: a data survey from 2009 to 2018].

OBJECTIVE: To analyze the using of pre-hospital emergency resources and treatment characteristics of acute alcoholism patients in Guangzhou. METHODS: The pre-hospital emergency data of the emergency department of the Second Affiliated Hospital of Guangzhou Medical University from January 1st in 2009 to December 31st in 2018 were obtained from the database of the Guangzhou Emergency Medical Command Center. The related data of patients with acute alcoholism were collected, including gender, age, poisoning severity, treatment results, caller type, number of empty vehicles (empty vehicle was defined as the empty vehicle return caused by the ambulance who did not receive or refused to come to the hospital after the ambulance leaved), departure time (from the ambulance to the completion time), on-site time (from the ambulance to the patient boarding time) and the distribution of pre-hospital emergency time in 24 hours on weekdays and weekends. The relationship between acute alcoholism patients and the peak of in-hospital emergency treatment was analyzed. RESULTS: A total of 2 408 acute alcoholism patients were recorded, among whom 2 109 patients (87.58%) with acute alcoholism,126 (5.23%) with drug poisoning, 67 (2.78%) with chemical poisoning, 3 (0.13%) with pesticide poisoning, and 103 (4.28%) with other poisoning. Acute alcoholism patients were mainly male, with a total of 1 862 cases (88.29%), and the ratio between males and females was 7.54:1. In 2 109 patients with acute alcoholism, 93.41% were in the age range of 18-59 years old. The number of mild patients was 1 717 (81.41%), 1 178 (55.86%) needed further treatment, and no patient died. For the occupation of pre-hospital emergency resources, 43.24% (912/2 109) of acute alcoholism called 120 through 110 with empty vehicles of 36.79% (776/2 109), which were significantly higher than the acute cerebrovascular disease [3.83% (362/9 461), 5.80% (549/9 461), both P < 0.01], acute trauma [24.29% (1 708/7 033), 7.96% (560/7 033), both P < 0.01], acute circulation system disease [2.44% (90/3 694), 2.87% (106/3 694), both P < 0.01], and acute respiratory system disease [0.86% (31/3 606), 1.58% (57/3 606), both P < 0.01]. Furthermore, empty vehicles were more likely to happen through 110 with empty vehicles rate of 51.75% (472/912), which was significantly higher than that through the witness [40.82% (60/147), P < 0.01] and relatives and friends [23.24% (244/1 050), P < 0.01]. The driving time and on-site time of acute alcoholism were significantly shorter than those of acute cerebrovascular disease, acute circulation system disease, and acute respiratory system disease [driving time (minutes): 26 (20, 34) vs. 34 (26, 45), 38 (29, 49), 38 (29, 50); on-site time (minutes): 6 (4, 10) vs. 10 (7, 14), 10 (7, 15), 10 (8, 15), all P < 0.01], but there was no statistical difference as compared with acute trauma [driving time (minutes): 26 (20, 34) vs. 29 (20, 42), on-site time (minutes): 6 (4, 10) vs. 7 (4, 11), both P > 0.05]. The regularity of variation in number of critically acute alcoholism patients was distinctive, which peaked in the period of 21:00-00:00 and bottomed out in the period of 09:00-13:00, which overlapped with the peak flow in the hospital emergency department (17:00-22:00). CONCLUSIONS: Acute alcoholism patients occupy excessive pre-hospital emergency resources, and overlap with the hospital emergency treatment peak. It is necessary to strengthen the public propaganda and education on the rational usage of 120 emergency resources and reduce waste.

Synthesis and Magnetic Properties of Ferroferric Oxide in Supercritical Methanol.

Ferroferric oxide was prepared using Fe(NO3)3 · 9H2O as the iron source under supercritical methanol conditions. Methanol was not only a solvent but also a reducing agent in the supercritical state. The effects of reaction temperature and time, and precursor concentration on product composition were investigated. In addition, ferromagnetic ferroferric oxide was synthesized in supercritical methanol with polyvinyl pyrrolidone (PVP) and polyethylene glycol (PEG) as surfactants. The as-synthesized products were characterized by XRD, SEM, FTIR techniques. Results showed that the addition of PVP and PEG had notable influences on the products. The findings also showed that ferroferric oxide of a loose flocculent structure and with a variable size (from several tens to a few hundred nanometers) had been prepared in supercritical methanol at 300 °C and 17.8 MPa for 15 min. Magnetic properties of the ferroferric oxide were detected by vibrating sample magnetometer. Its saturation magnetization was 50 emu/g, which was lower than the bulk value of 92 emu/g and showed that it had ferromagnetism.

Differential physiological and metabolic response to low temperature in two zoysiagrass genotypes native to high and low latitude.

Low temperature is one of the important limiting factors for growing season and geographical distribution of plants. Zoysiagrass (Zoysia Willd) is one of the widely used warm-season turfgrass that is distribute in many parts of the world. Zoysaigrass native to high latitude may have evolved higher cold tolerance than the ones native to low latitude. The objective of this study was to investigate the cold stress response in zoysiagrass native to diverse latitude at phenotypic, physiological and metabolic levels. Two zoysiagrass (Z. japonica) genotypes, Latitude-40 (higher latitude) and Latitude-22 (lower latitude) were subjected to four temperature treatments (optimum, 30/25°C, day/night; suboptimum, 18/12°C; chilling, 8/2°C; freezing, 2/-4°C) progressively in growth chambers. Low temperature (chilling and freezing) increased leaf electrolyte leakage (EL) and reduced plant growth, turf quality, chlorophyll (Chl) content, photochemical efficiency (Fv/Fm) and photosynthesis (Pn, net photosynthetic rate; gs, stomatal conductance; intercellular CO2; Tr, transpiration rate) in two genotypes, with more rapid changes in Latitude-22. Leaf carbohydrates content (glucose, fructose, sucrose, trehalose, fructan, starch) increased with the decreasing of temperature, to a great extend in Latitude-40. Leaf abscisic acid (ABA), salicylic acid (SA) and jasmonic acid (JA) content increased, while indole-3-acetic acid (IAA), gibberellic acid (GA3) and trans-zeatin ribside (t-ZR) content decreased with the reduction of temperature, with higher content in Latitude-40 than in Latitude-22. Chilling and freezing induced the up-regulation of C-repeat binding factor (ZjCBF), late embryogenesis abundant (ZjLEA3) and dehydration-responsive element binding (ZjDREB1) transcription factors in two genotypes, whereas those genes exhibited higher expression levels in Latitude-40, particularly under freezing temperature. These results suggested that zoysiagrass native to higher latitude exhibited higher freezing tolerance may attribute to the higher carbohydrates serving as energy reserves and stress protectants that stabilize cellular membranes. The phytohormones may serve signals in regulating plant growth, development and adaptation to low temperature as well as inducing the up-regulated ZjCBF, ZjLEA3 and ZjDREB1 expressions thus result in a higher cold tolerance.

Ambient particulate matter air pollution associated with acute respiratory distress syndrome in Guangzhou, China.

Limited evidence exists concerning the impact of particulate pollution on acute respiratory distress syndrome (ARDS). We examined the effects of particulate pollution on emergency ambulance dispatches (EAD) for ARDS in Guangzhou, China. Daily air pollution concentrations for PM10, PM2.5, and PM1, as well as PM2.5 chemical compositions, were available from a central air monitoring station. The association between incident ARDS and air pollution on the concurrent and previous 5 days was estimated by an over-dispersed Poisson generalized additive model controlling for meteorological factors, temporal trends, public holidays and day of the week. We identified a total of 17,002 EADs for ARDS during the study period. There were significant associations between concentrations of PM10, PM2.5, PM1, and ARDS; corresponding excess risk (ER) for an interquartile range IQR increase in 1-day lagged concentration was 5.45% [95% confidence interval (CI): 1.70%, 9.33%] for PM10 (45.4 µg/m3), 4.71% (95% CI: 1.09%, 8.46%) for PM2.5 (31.5 µg/m3), and 4.45% (95% CI: 0.81%, 8.23%) for PM1 (28.8 µg/m3), respectively. For PM2.5 chemical compositions, we found that OC, EC, sulfate and ammonium were significantly associated with ARDS. The observed effects remained even after adjusting for potentially confounding factors. This study suggests that PM10, PM2.5, and PM1, as well as chemical constituents from combustion and secondary aerosols might be important triggers of ARDS in Guangzhou.

Integrating Metal-Enhanced Fluorescence and Surface Acoustic Waves for Sensitive and Rapid Quantification of Cancer Biomarkers from Real Matrices.

Metal-enhanced fluorescence (MEF) is utilized to lower the detection limit of carcinoembryonic antigen (CEA), a prognostic biomarker for colorectal cancer among others, in immunofluorescence assays. In addition, Rayleigh surface acoustic waves (SAWs) were utilized to remove nonspecifically bound proteins, improve mixing, and reduce incubation times. Fluorescence intensity was plasmonically enhanced by incubating silver nanocubes (AgNCs) of 50 nm edge-length on a SAW device. This increased sensor sensitivity by a factor of 6 and lowered the limit of detection to below 1 ng/mL in fluorescence detection of the antigen. Surface density of the AgNCs was optimized to produce the largest MEF, which increased the signal intensity by an order of magnitude. Acoustic streaming induced by Rayleigh SAWs was found to decrease antibody/antigen incubation times to 1/6th of the values without such micromixing, and to increase the fluorescence signal strength. Overall, the demonstrated results allow for construction of a sensor capable of detecting CEA rapidly in clinically relevant concentrations. Variables relevant for optimizing this sensor performance were identified, which will enable even better performance in immunofluorescence assays.

Boron-doped graphene as a metal-free catalyst for gas-phase oxidation of benzyl alcohol to benzaldehyde.

Boron-doped graphene samples (BGs) with tunable boron content of 0-2.90 at% were synthesized and directly used in the gas-phase oxidation of benzyl alcohol to benzaldehyde, and showed excellent performance. XPS results indicated that the graphitic sp2 B species (BC3) is the mainly boron dopant species incorporated in the graphene lattice, which could significantly improve the content of ketone carbonyl groups (C[double bond, length as m-dash]O) on the graphene. For instance, the contents of C[double bond, length as m-dash]O jumped from 1.93 to 4.19 at% while BC3 doped into the graphene lattice was only 0.35 at%. The C[double bond, length as m-dash]O is the active site of catalytic reaction, so BG has significantly improved catalytic activity. Compared to the un-doped graphene (G), the conversion of benzyl alcohol over BGs increased 2.35 times and the selectivity of benzaldehyde increased from 77.3% to 99.2%. Aerobic-anaerobic exchange experiments revealed that the superior catalytic performance of BG was achieved only under aerobic conditions. The study of the boron-doped carbocatalyst may also provide guidance for the design of surface modified carbon-based catalysts for the selective oxidation dehydrogenation of alcohols by regulating doping elements and their types.

Gold nanoparticle-based low limit of detection Love wave biosensor for carcinoembryonic antigens.

In this work, a Love wave biosensing platform is described for detecting cancer-related biomarker carcinoembryonic antigen (CEA). An ST 90°-X quartz Love wave device with a layer of SiO2 waveguide was combined with gold nanoparticles (Au NPs) to amplify the mass loading effect of the acoustic wave sensor to achieve a limit of detection of 37pg/mL. The strategy involves modifying the Au NPs with anti-CEA antibody conjugates to form nanoprobes in a sandwich immunoassay. The unamplified detection limit of the Love wave biosensor is 9.4ng/mL. This 2-3 order of magnitude reduction in the limit of detection brings the SAW platform into the range useful for clinical diagnosis. Measurement electronics and microfluidics are easily constructed for acoustic wave biosensors, such as the Love wave device described here, allowing for robust platforms for point of care applications for cancer biomarkers in general.

Theoretical Study of Monolayer and Double-Layer Waveguide Love Wave Sensors for Achieving High Sensitivity.

Love wave sensors have been widely used for sensing applications. In this work, we introduce the theoretical analysis of the monolayer and double-layer waveguide Love wave sensors. The velocity, particle displacement and energy distribution of Love waves were analyzed. Using the variations of the energy repartition, the sensitivity coefficients of Love wave sensors were calculated. To achieve a higher sensitivity coefficient, a thin gold layer was added as the second waveguide on top of the silicon dioxide (SiO2) waveguide-based, 36 degree-rotated, Y-cut, X-propagating lithium tantalate (36° YX LiTaO3) Love wave sensor. The Love wave velocity was significantly reduced by the added gold layer, and the flow of wave energy into the waveguide layer from the substrate was enhanced. By using the double-layer structure, almost a 72-fold enhancement in the sensitivity coefficient was achieved compared to the monolayer structure. Additionally, the thickness of the SiO2 layer was also reduced with the application of the gold layer, resulting in easier device fabrication. This study allows for the possibility of designing and realizing robust Love wave sensors with high sensitivity and a low limit of detection.