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A Novel Multilayer Sandwich Fabric-based Composite Material for Infrared Stealth and Super Thermal Insulation Protection
摘要： At present, infrared stealth materials for advanced detection and stealth technology is usually prepared with low emissivity coating on the surface, but there are very few efficient infrared stealth materials based on textiles with lightweight and flexible features. In this paper, we designed a carbon nanotube-doped aerogel (CNTAs) sandwich structure on polyimide (PI) fabric by hot pressing and then coated with a low emissivity Al-doped ZnO (ZAO) on the outer surface. The surface emissivity lower than 0.5 due to the existence of ZAO and the thermal conductivity of the intermediate interlayer aerogels as low as 0.013 W/(m?K). Additionally, through experiments, theoretical derivation and simulation analysis, we found the resultant composite demonstrated a high infrared stealth performance with super insulation effect, implying it will have a fine prospect in infrared stealth and thermal insulation protection fields with its unique structure and excellent properties.
关键词： Carbon Nanotube-doped Aerogel,Sandwich Structure,Infrared Stealth,Polyimide Fabric,Thermal Insulation,Al-doped ZnO
更新于2025-09-23 15:23:52
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Third Order Nonlinear Properties of Pure and Na doped L-Arginine Acetate Single Crystal by Z-scan Technique
摘要： Single crystals of pure and Na doped L-arginine acetate (LAA) has been successfully grown from aqueous solution by slow evaporation technique. The crystalline qualities of the grown crystals were confirmed by powder X-ray diffraction studies. The nonlinear refractive index n2 and nonlinear susceptibility c(3) have been measured through the Z-scan technique. The results indicate that the compound exhibits reverse saturation absorption and self defocusing performance. Non-linear absorption co-efficient (b), the non-linear refractive index (n2), the real and imaginary parts of non-linear susceptibility c (3) have been measured at 632.8 nm.
关键词： Z-scan Technique,Na doped L-arginine acetate (LAA),Crystal
更新于2025-09-23 15:23:52
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Wafer-scale Fabrication of Nitrogen-doped Reduced Graphene Oxide with Enhanced Quaternary-N for High-Performance Photodetection
摘要： We demonstrated a simple and scalable fabrication route of nitrogen-doped reduced graphene oxide (N-rGO) photodetector on 8-inch wafer-scale. The N-rGO was prepared through in-situ plasma-treatment in an acetylene-ammonia atmosphere to achieve n-type semiconductor with substantial formation of quaternary-N substituted into the graphene lattice. The morphology, structural, chemical composition and electrical properties of the N-rGO was carefully characterized and being used for the device fabrication. The N-rGO devices were fabricated in a simple metal-semiconductor-metal (MSM) structure with unconventional metal-on-bottom configuration to promote high-performance photodetection. The N-rGO devices exhibited enhanced photoresponsivity as high as 0.68 A W?1 at 1.0 V, which is about two orders of magnitude higher compared to a pristine graphene and wide-band photo-induced response from visible to near-infrared (NIR) region with increasing sensitivity in the order of 785 nm, 632.8 nm and 473 nm excitation wavelengths. We also further demonstrated a symmetric characteristic of photo-induced response to any position of local laser excitation with respect to the electrodes. The excellent features of wafer-scale N-rGO devices suggest a promising route to merge the current silicon technology and two-dimensional materials for future optoelectronic devices.
关键词： photodetector,plasma treatment,quaternary-N,wafer-scale fabrication,Nitrogen-doped reduced graphene oxide
更新于2025-09-23 15:23:52
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Manganese-doped zinc oxide hollow balls for chemiresistive sensing of acetone vapors
摘要： Both pure and Mn(II)-doped ZnO hollow structures were synthesized by a solvothermal reaction, and their phase structures, morphologies and elemental composition were characterized. SEM and TEM observations show the pure ZnO and the Mn(II)-doped ZnO balls to possess similar hollow structure with a particle size of about 1.5 μm. Their sensing properties were investigated, and the composite containing 1 atom% of Mn(II) (1% Mn-ZnO) is found be display the highest selectivity for acetone. The detection limit is 100 ppm acetone at 234 °C which is 4.6 times lower than that of the pure ZnO. In addition, the response time is shorter.
关键词： Hollow balls,Gas sensor,ZnO,Acetone vapors,Mn-doped ZnO
更新于2025-09-23 15:23:52
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Finite bias evolution of bosonic insulating phase and zero bias conductance in boron-doped diamond: A charge-Kondo effect
摘要： We report novel transport features in heavily boron-doped nanocrystalline diamond films, in particular an anomalous resistance peak near to the superconducting transition temperature and a strong zero bias conductance peak in the differential current-voltage spectra. The shape of the resistance-temperature curves near the critical temperature is seen to be strongly influenced by both magnetic field and bias current. As the bias current is lowered, the resistance peak becomes more pronounced, whereas when the magnetic field is varied the peak shifts towards lower temperatures. The resistance upturn shows a quadratic temperature dependence as expected for a Kondo transition. We find that a number of transport features such as resistance peak height, zero bias conduction peak height and width scale according to a power law dependence. We interpret these features as a result of a charge-Kondo effect where hole dopants act as degenerate Kondo impurities by opening additional pseudo-spin scattering channels.
关键词： bosonic insulating phase,zero bias conductance peak,charge-Kondo effect,boron-doped diamond,superconductivity
更新于2025-09-23 15:23:52
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Preparation of Rod-like Aluminum Doped Zinc Oxide Powders by Sol-gel Technique Using Metal Chlorides and Acetylacetone Precursors
摘要： Al-doped ZnO (AZO) powders were prepared by using metal chloride precursors and the sol-gel technique. IR peaks observed at 1590 cm-1 and 1620 cm-1 indicated the formation of metal chelate as a consequence of the addition of acetylacetone to the metal chloride solution. TG-DSC analysis of the AZO gels confirmed the formation of metal chelate as evidenced by the development of several weight loss peaks accompanied by the introduction of new endothermic peaks. The resulting AZO gels were annealed at 500, 600, and 800 ℃ to study the effect of annealing temperature. XRD and SEM results showed that crystallization of AZO gels takes place around 600 ℃. Hexagonal wurtzite structure was identified as the main phase for all the samples. In addition, small shift of the XRD (002) peak coupled with XPS results from the AZO powders confirmed the successful doping of the ZnO powders. Micron sized rod-like AZO powders were uniform in dimension and morphology and remained stable even at 800 ℃.
关键词： rod-like,aluminum doped ZnO,sol gel,metal chloride,acetylacetone
更新于2025-09-23 15:23:52
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Comparative analysis of capacity oriented Integrated AMI modulation technique for the deployment of radio over fiber system
摘要： To improve the spectral efficiency and to reduce non-linear distortion in the optical system, various advanced modulation techniques have been investigated for radio over fiber (RoF) system. The investigation indicates the high data rate distortion less transmission for long-haul RoF system still further investigation is required to improve spectral efficiency and to get the reduction in signal degradation. In this paper, an advanced modulation technique referred as integrated alternate mark inversion modulation technique based upon external modulation (electro-absorption modulator) has been designed and simulated. The results show better performance in terms of performance metrics i.e. Q-factor (25.15) and BER (4e-140) and also enhance the data transmission capabilities up to 100 Gbps covering the long distance of 250 km resulting a reasonable reduction in signal degradation particularly chromatic dispersion effects for long-haul transmissions.
关键词： Single mode fiber—SMF,Carrier suppressed return to zero—CSRZ,Erbium doped fiber amplifier—EDFA,RoF,Dispersion compensating fiber—DCF,Multi-mode fiber—MMF
更新于2025-09-23 15:23:52
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Sn-doped and porogen-modified TiO2 photocatalyst for solar light elimination of sulfure diethyle as a model for chemical warfare agent
摘要： In the context of the increase in chemical threat due to warfare agents, the development of efficient methods for destruction of Chemical Warfare Agents are of first importance both for civilian and military purposes. Here, we demonstrate that optimized Sn-TiO2 doped and PEG-modified photocatalysts allow increased and high performances under UV-A and solar-light irradiations leading to total elimination of highly contaminated environments containing Diethylsulfide (DES) used as a model molecule mimicking Yperite (Mustard Gas). It has been shown that Sn doping induces significant modifications on the structural, morphological, surface, electronic and optical properties of TiO2. For example, the addition of 1% Sn increases significantly the surface area from 30 to 80 m2/g and decreases the particle size, while Sn-doping results in a reduction of the anatase band-gap from 3.2 to 2.95 eV. Total DES elimination could be reached for 90 and 120 min under continuous contaminant flux under UV-A and solar light activation, respectively accompanied with limited deactivation phenomenon. Correlations between the resulting physico-chemical properties of the doped and PEG-modified materials and the photocatalytic activities were carried out. The results open up extremely promising way for the decontamination of highly contaminated environments containing real warfare agents under UV-A but also under solar light illumination.
关键词： DES elimination,PEG-modified TiO2,UV-A and solar light activation,Sn-doped TiO2
更新于2025-09-23 15:23:52
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Photocatalytic oxidation of gaseous benzene, toluene and xylene under UV and visible irradiation over Mn-doped TiO2 nanoparticles
摘要： The photocatalytic oxidation of gaseous benzene, toluene and xylene (BTX) over un-doped, 0.1 and 1 wt% Mn-TiO2 nanoparticles under ultraviolet and visible irradiation was studied in atmosphere of synthetic air or inert gas. The photocatalytic decomposition efficiency and the oxidation products were determined using a Static Photochemical Reactor coupled with FTIR spectroscopy. BTX underwent efficient decomposition over Mn-TiO2 photocatalysts under UV irradiation, more with oxygen presence and less without oxygen. More important toluene and xylene went substantial decomposition over 0.1 mol% Mn-TiO2 under visible irradiation with oxygen presence. The main final oxidation products in the UV photocatalysis of BTX were CO2, CO and H2O, with CO2 and CO yields 4 and 2 respectively. The conversion percentage of benzene, toluene, and xylene to CO2 were 63.6%, 56.4%, 51.8%, and to CO 29%, 26.5%, 23.2%, respectively. In the visible photocatalysis of toluene and xylene the yields of CO were insignificant. Formation of carbon containing deposits on TiO2 surfaces was observed after extensive UV photocatalysis of toluene and xylene, and such by-products surface coverage may reduce the photocatalytic activity of TiO2 samples. Some aspects of the photocatalytic mechanism were examined.
关键词： Mn-doped TiO2,Visible - light photocatalysis,Photodegradation of Benzene,Indoors air pollution,Xylene,Toluene
更新于2025-09-23 15:23:52
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Tuning the excitonic properties of ZnO:Sn thin films
摘要： The effects of Sn doping, deposition temperature, and post-annealing treatment on the excitonic behavior of ZnO:Sn (SZO) thin films deposited by dc-unbalanced magnetron sputtering have been studied. Sn doping induces the decrease of grain size and promotes the formation of oxygen vacancy-related trap states as indicated by A1 LO mode in Raman spectra and green emission in photoluminescence spectra. Using a critical point analysis of the dielectric functions from spectroscopic ellipsometry data analysis, Sn doping blueshifts the excitonic absorption and decreases the exciton lifetime via screening the electron-hole Coulomb interaction. By varying the deposition temperature from room temperature up to 300 °C (SZO-3), there is no change in excitonic absorption. Then, annealing of SZO-3 at 600 °C under oxygen environment (SZO-6) strongly improves the excitonic absorption as well as its lifetime. Critical point analysis on SZO-6 sample clearly reveals the excitonic transition at 3.38 eV and exciton-phonon complexes at 3.66 eV. Thus, the result is important to improve the functionality of doped ZnO with strong excitonic absorption for optoelectronic applications.
关键词： Annealing,Dc-unbalanced magnetron sputtering,Exciton,Thin films,Sn doped ZnO
更新于2025-09-23 15:23:52