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Indium Nitrite (InN)-Based Ultrasensitive and Selective Ammonia Sensor Using an External Silicone Oil Filter for Medical Application
摘要： Ammonia is an essential biomarker for noninvasive diagnosis of liver malfunction. Therefore, selective detection of ammonia is essential for medical application. Here, we demonstrate a portable device to selectively detect sub-ppm ammonia gas. The presented gas sensor is composed of a Pt coating on top of an ultrathin Indium nitrite (InN) epilayer with a lower detection limit of 0.2 ppm, at operating temperature of 200 ?C, and detection time of 1 min. The sensor connected with the external ?lter of nonpolar 500 CS silicone oil to diagnose liver malfunction. The absorption of 0.7 ppm acetone and 0.4 ppm ammonia gas in 10 cc silicone oil is 80% (0.56 ppm) and 21.11% (0.084 ppm), respectively, with a ?ow rate of 10 cc/min at 25?C. The absorption of acetone gas is 6.66-fold higher as compared to ammonia gas. The percentage variation in response for 0.7 ppm ammonia and 0.7 ppm acetone with and without silicone oil on InN sensor is 17.5% and 4%, and 22.5%, and 14% respectively. Furthermore, the percentage variation in response for 0.7 ppm ammonia gas with silicone oil on InN sensor is 4.3-fold higher than that of 0.7 ppm acetone. The results show that the InN sensor is suitable for diagnosis of liver malfunction.
关键词： silicone oil,InN,liver malfunction,exhaled-breath volatile organic compound (VOCs),selectivity,external ?lter
更新于2025-09-10 09:29:36
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Ultra-wideband side-lobe level suppression using amplitude-adjustable metasurfaces
摘要： An amplitude-adjustable metasurface has been proposed to suppress the side-lobe level over an extra-wide frequency band. A polarization-selective unit cell (PSUC) is designed to constitute the metasurface, which can manipulate the amplitudes of the co-polarization reflection coefficients and cross-polarization transmission coefficients while the phases remain unchanged. The amplitude of the metasurfaces is discretely Taylor distributed. As examples, two metasurfaces were designed to achieve SLLS of reflected and transmitted beams, respectively. The simulations demonstrated that two metasurfaces have good performance on SLLS of reflected/transmitted beams with approximate -20dB SLL in a wide frequency region. It is expected that the designed amplitude-adjusted metasurfaces may find potential application in antennas and stealth techniques.
关键词： Taylor current coefficients,side-lobe level suppression,polarization-selectivity
更新于2025-09-10 09:29:36
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Novel Functional TPE Polymers: Aggregation-Induced Emission, pH Response, and Solvatochromic Behavior
摘要： Four tetraphenylethylene (TPE)-based aryleneethynylene polymers with amino or nitro groups are reported. They display strong aggregation-induced emission (AIE). The functional groups trigger acidochromic changes in the emission behavior of these polymers. Amino-substituted P1–P3 exhibit pH response through protonation of the amino groups. The position of the amino groups (on TPE or the side chains) influences the fluorescence intensity or emission wavelength as a response to different pH values. Nitro-P4 is solvatochromic due to its donor–acceptor structure. AIE, intramolecular charge transfer, and F?rster resonance energy transfer define the fluorescence-based performance of the polymers. The amino-functionalized TPE polymers show excellent nitroarene-sensing performance. P4 is less effective than the amino polymers. A sensor array based on P1–P3 identifies 12 different nitroarenes in water.
关键词： selectivity,fluorescence,conjugated polymers,modification
更新于2025-09-10 09:29:36
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Dual-Band Binary Metamaterial Absorber Based on Low-Permittivity All-Dielectric Resonance Surface
摘要： A binary-structured metamaterial absorber (BMA) consisting of a low-permittivity dual-layer all-dielectric resonance surface (ADRS) and re?ector was simulated and experimentally validated. Analyses of relative impedance, electric/magnetic ?eld and power loss density indicated that the proposed BMA exhibits two absorption peaks at 14.65 GHz and 16.61 GHz, resulting from the magnetic and electrical responses of ADRS, respectively. The dependences of absorption properties on the dimensions of the ADRS and material parameters of the ADRS are discussed. It is concluded that the upper layer of the ADRS acts as an impedance-matching layer directly in?uencing the absorption intensity, while the bottom layer offers frequency selectivity in the 13–15 GHz range. The current design uses a low-permittivity ADRS, with simpli?ed design and easy preparation and is notably different from conventional ternary-structured metamaterial absorbers based on a metallic resonance surface. The simplicity of the proposed BMA makes it a promising low-cost ambient temperature alternative to conventional metamaterial absorbers and could open up practical applications.
关键词： Binary-structured metamaterial absorber,simpli?ed design and easy preparation,frequency selectivity,low-permittivity all-dielectric resonance surface
更新于2025-09-10 09:29:36
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Photocatalytic Oxidation of Aniline over MO/TiO2 (M = Mg, Ca, Sr, Ba) under visible light irradiation
摘要： MO/TiO2 (M=Mg, Ca, Sr & Ba; TiO2: Evonik Aroxide P25) composites were prepared for photocatalytic aniline oxidation under visible light irradiation. The conversion efficiencies of aniline over the samples are revealed as follow order: BaO/TiO2>SrO/TiO2>CaO/TiO2>MgO/TiO2. The combined results of XPS and CO2 TPD indicate that the electron density of lattice oxygen and the surface basicity for the photocatalysts became higher and higher with the atomic number increase of the alkaline metal elements, in accordance with the order of the conversion efficiency. The sample SrO/TiO2 shows the highest nitrosobenzene selectivity. BaO/TiO2 with highest surface basicity may facilitate the further aniline transformation to nitrobenzene and azobenzene, resulting in lower selectivity for nitrosobenzene. Surface complexes formed on the basic sites of the catalysts via aniline chemsorption would be acted as active sites and be excited for the photocatalytic oxidation of aniline under visible light irradiation.
关键词： MO/TiO2,Surface Basicity,Photocatalytic Aniline Oxidation,Surface Complexes,Conversion and Selectivity
更新于2025-09-10 09:29:36
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Molecule-Driven Shape Control of Metal Co-Catalysts for Selective CO? Conversion Photocatalysis
摘要： In photocatalysis of CO2 conversion, metal co-catalysts draw photo-generated electrons from semiconductor components and act as reaction sites by adsorbing CO2 and its intermediates. Optimization of the metal co-catalyst structure is indispensable to improving the efficiency of the photocatalyst, which is currently not meeting performance requirements. By performing a series of experiments and simulations, we demonstrate the effect of selective particle shape control of metal co-catalysts (Au, Ag, Cu and Pt) by the CO2 induced gas ligands (CO2 and CO) on photocatalytic CO2 conversion activity and selectivity. Indeed, facet formation for adsorption of CO2 and CO proves to be an effective way to improve the CO2 conversion activity. In particular, proper interaction between the gas ligand and the metal co-catalyst surface, realized by strengthening the metal-CO2 adsorption and weakening the metal-CO adsorption, is identified as essential factor for increasing the CO2 conversion activity. Pt and Cu, which exhibit relatively strong interaction with gas molecules, have the improved photocatalytic CO2 conversion activity when grown under CO2. In contrast, Au and Ag, which exhibit relatively weak interaction with gas molecules, have the enhanced photocatalytic CO2 conversion activity when grown under CO. This systematic understanding can be a guideline for controlling the metal co-catalyst surface structure and will maximize the photocatalytic selectivity of the CO2 conversion.
关键词： CO2 reduction,Activity and selectivity,Transition metal co-catalyst,Facet control,Photocatalyst
更新于2025-09-10 09:29:36
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[IEEE 2018 34th International Conference on Lightning Protection (ICLP) - Rzeszow (2018.9.2-2018.9.7)] 2018 34th International Conference on Lightning Protection (ICLP) - Optical Lightning Measurement System and First Results
摘要： This paper introduces a newly developed optical lightning measurement system (OLMS). The OLMS is based on a video system using a camera with a 360° panorama view and a frame rate of 60 frames per second. The OLMS locates the lightning from the direction of the illuminated lightning channel and the travel time of the thunder sound. The analysis comprises 34 flashes containing 144 strokes, which occurred during the time period from 30th of July 2017 to 24th of August 2017. The results are compared to data obtained by the European lightning location network EUCLID. The comparison revealed a flash detection efficiency of 100 % and a stroke detection efficiency of 93.1 % for EUCLID. With EUCLID, the fraction of 92.5 % was classified correctly as cloud-to-ground lightning and the minor fraction of 7.5 % was miss-classified as cloud-to-cloud lightning. On average (arithmetic mean), the negative flashes contained 4.3 return strokes with 1.7 different striking points. For multi-stroke flashes with return strokes using the same lightning channel, EUCLID located the individual striking points with a median deviation of 57.3 m. The average striking distance was about 10 km. Due to the far distance the thunder sound could often not be separated from the thunder sound of other lightning. Therefore, the OLMS located the lightning with a relatively high deviation compared to the data of EUCLID. The arithmetic (geometric) mean value of the deviation was 1330 m (670 m).
关键词： optical measurement,detection efficiency,Lightning location system (LLS),multiple lightning flash,location accuracy,selectivity CG/CC
更新于2025-09-09 09:28:46
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Highly sensitive gas sensor based on Er-doped SnO2 nanostructures and its temperature dependent selectivity towards hydrogen and ethanol
摘要： In the present work, impact of Er3+ doping on the response and selectivity of SnO2 based gas sensor has been investigated in detail. X-ray diffraction (XRD) results confirmed formation of a tetragonal rutile structure of undoped and erbium doped SnO2 nanoparticles. It has been observed that specific surface area of nanoparticles has increased with increase in dopant concentration. The oxidation states and presence of erbium in SnO2 lattice has been confirmed by X-ray photoelectron spectroscopy (XPS). Photoluminescence (PL) analysis revealed that concentration of oxygen vacancies increases with increase in dopant incorporation. It has been observed that 3% Er-doped SnO2 sensor exhibited enhanced sensor response and temperature dependent selectivity towards ethanol and hydrogen at 240 and 360℃ respectively. The enhanced sensor response of the fabricated sensor has been ascribed to large surface area, enormous oxygen vacancies and elevated surface basicity of doped nanoparticles used. The tunable dual selectivity of 3% doped sensor towards ethanol and hydrogen makes it a perfect candidate for ethanol-hydrogen sensing for ethanol steam reforming systems combined to fuel cells.
关键词： hydrogen,nanoparticles,ethanol,gas sensor,selectivity
更新于2025-09-09 09:28:46
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SiC-TiC nanocomposite for bulk solar absorbers applications: Effect of density and surface roughness on the optical properties
摘要： In this study, the potential of SiC-TiC nano-composites as solar absorbers has been studied. For solar thermal applications, materials with high solar absorptance and low emittance are ideally sought for (spectral selectivity). A semi-molecular sol-gel synthesis route leading to nanometric homogenous composites was described. The resulting SiC-TiC nanocomposite powder was sintered at different temperatures to produce samples with various relative densities (from 57% to 96%). The samples morphology and composition were characterized by several techniques including Scanning Electron Microscopy (SEM), Energy-Dispersive X-Ray Spectroscopy (EDX), X-Ray Diffraction (XRD), carbon and oxygen elemental analyses. The link between the surface roughness and the relative density was precised and the effects on the optical properties (0.25–25 μm wavelength range) were studied. Comparisons were made with pure SiC and pure TiC samples with various relative densities. Overall, the sample emittance was found to strongly decrease with the increase in the relative density, leading to a great increase in the spectral selectivity, despite a little decrease in the solar absorptance. The TiC-SiC composite has an intermediate reflectance compared to the pure SiC and the pure TiC samples. With an absorptance of 0.76, an emittance of 0.44 and a selectivity of 1.74, the denser SiC-TiC could be a good candidate for bulk solar applications.
关键词： Concentrated Solar Power,TiC,Selectivity,Density,SiC,Roughness
更新于2025-09-09 09:28:46
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Highly Efficient and Robust Photocatalytic Systems for CO <sub/>2</sub> Reduction Consisting of a Cu(I) Photosensitizer and Mn(I) Catalysts
摘要： The development of highly efficient, selective, and durable photocatalytic CO2 reduction systems that only use earth-abundant elements is key for both solving global warming and tackling the shortage of energy and carbon resources. Here, we successfully developed CO2 reduction photocatalysts using [Cu2(P2bph)2]2+ (CuPS) (P2bph = 4,7-diphenyl-2,9-di(diphenylphosphinotetramethylene)-1,10-phenanthroline) as a redox photosensitizer and fac-Mn(X2bpy)(CO)3Br (Mn(4X)) (X2bpy = 4,4′-X2-2,2′-bipyridine (X = ?H and ?OMe) or Mn(6mes) (6mes = 6,6′-(mesityl)2-2,2′-bipyridne)) as the catalyst. The most efficient photocatalysis was achieved by Mn(4OMe): The total quantum yield of CO2 reduction products was 57%, the turnover number based on the Mn catalyst was over 1300, and the selectivity of CO2 reduction was 95%. Electronic and steric effects of the substituents (X) in the Mn complexes largely affected both the photocatalytic efficiency and the product selectivity. For example, the highest selectivity of CO formation was achieved by using Mn(6mes) (selectivity SCO = 96.6%), whereas the photocatalytic system using Mn(4H) yielded HCOOH as the main product (SHCOOH = 74.6%) with CO and H2 as minor products (SCO = 23.7%, SH2 = 1.7%). In these photocatalytic reactions, CuPS played its role as an efficient and very durable redox photosensitizer, while remaining stable in the reaction solution even after a turnover number of 200 had been reached (the catalyst used had a turnover number of over 1000).
关键词： turnover number,Cu(I) photosensitizer,Mn(I) catalysts,photocatalytic CO2 reduction,earth-abundant elements,quantum yield,product selectivity
更新于2025-09-09 09:28:46