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oe1(光电查) - 科学论文

738 条数据
?? 中文(中国)
  • Effects of sintering conditions on the microstructure and mechanical properties of SiC prepared using powders recovered from kerf loss sludge

    摘要: The effects of sintering conditions on the microstructure and mechanical properties of the sintered SiC prepared using the SiC powder recovered from the kerf loss sludge were investigated. The recovered SiC powders were consolidated by spark plasma sintering (SPS) and conventional sintering methods. The effects of sintering temperature, time and methods (SPS and conventional sintering) on the phase, grain size and density of SiC were systematically studied. The Vickers hardness of spark plasma-sintered (SPSed) samples was higher than that of conventional sintered samples due to small grain size. When holding time was increased from 10 to 30 min, the grain size and relative density of SPSed samples were also increased, which lead to the almost constant Vickers hardness by competing effects of grain size and relative density. When holding time was over 30 min, no appreciable change of the relative density and grain size were observed, which can lead to similar values of Vickers hardness. SPS process can be used to make SiC with high density and hardness at relatively low temperature compared with the conventional sintering process.

    关键词: Recovered SiC,spark plasma sintering (SPS),sintering conditions,conventional sintering

    更新于2025-09-10 09:29:36

  • Unidirectional Absorption in a Three-Dimensional Tunable Absorber Under Oblique Incidence

    摘要: In this paper, we propose a three-dimensional tunable absorber to realize a controllable unidirectional absorption and unidirectional transmission based on the plasma metamaterial, which includes two metamaterial layers that are vertical to each other. Each side of the proposed absorber integrates two split-ring resonators, which are made in the solid-state plasma (SSP). Unidirectional absorption and unidirectional transmission can be achieved when the incident angle of the electromagnetic wave is 30°. Furthermore, the unidirectional absorption and unidirectional transmission can be manipulated through exciting the different SSP resonators and adjusting the positions of the corresponding gaps between the two SSP resonators. In addition, the tunable absorption and transmission spectra can be obtained when the different SSP resonators are excited.

    关键词: Unidirectional transmission,Plasma metamaterial,Unidirectional absorption

    更新于2025-09-10 09:29:36

  • A comparison of emissive and cold floating probe techniques for electric potential measurements in rf inductive discharge

    摘要: A cold floating probe method was compared with the emissive floating probe method in terms of a low-pressure radio-frequency inductive discharge. The dependences of difference between the plasma potential and the floating potential on the electron temperature 1–8 eV, plasma density 109–1012 cm-3 and magnetic field 100–650 G were obtained. It was demonstrated that the difference between the potentials that obtained by these two methods can differ significantly from the expected value of 5.2 kTe/e for argon.

    关键词: plasma potential,floating probe,rf inductive discharge,emissive probe

    更新于2025-09-10 09:29:36

  • A tunable broadband filter of ternary photonic crystal containing plasma and superconducting material

    摘要: This work reports the optical properties of a one-dimensional (1D) ternary periodic structure composed of a dielectric, magnetized cold plasma (MCP) and superconducting material by using well-known simple transfer matrix method. The MCP has considered right-hand and left-hand polarizations having positive (? B) and negative (- B) transverse magnetic ?eld, respectively. The transmittance of the ternary photonic crystals is analyzed by varying the angle of incidence, the magnetic ?eld, the electron density of the magnetized cold plasma, the temperature of the superconductor, the thickness of magnetized cold plasma and superconducting material for the right-hand and left-hand polarization structures. The transmittance of the ternary photonic crystal containing dielectric, magnetized cold plasma and superconducting material has tunable broadband and narrowband ?lters for the left-hand and right-hand polarizations, respectively. The magnetized cold plasma layer in the ternary photonic crystal also played an important role to form the tunable gap due to the transverse magnetic ?eld. The analysis of the transmittance of the ternary photonic crystal containing dielectric, magnetized cold plasma and superconducting materials has shown an innovative idea for the formation of the tunable broadband and the narrowband ?lters.

    关键词: 1D ternary photonic crystal,Magnetized cold plasma,Tunable broadband and narrowband ?lters,Superconducting material

    更新于2025-09-10 09:29:36

  • Fabrication of Gd-La codoped TiO2 composite via a liquid phase plasma method and its application as visible-light photocatalysts

    摘要: TiO2 was doped simultaneously with Gd and La using a liquid phase plasma (LPP) reaction to produce a photocatalyst with excellent photoactivity in the visible light region. Gadolinium chloride hexahydrate and lanthanum chloride heptahydrate precursors were used to dope the TiO2 powder with polycrystalline Gd2O3 and La2O3 particles. The doping of TiO2 with rare earth elements using LPP reaction decreased the band gap; the band gap of Gd-La codoped TiO2 photocatalysts (GLTP) was the lowest. The photodegradation efficiency of the TiO2 photocatalysts doped with either Gd or La was superior that of bare TiO2 but the photodegradation efficiency of GLTP was highest in both ultraviolet and visible light sources. Acetaminophen (Acetyl-para-aminophen, APAP) was ultimately decomposed to CO2 and H2O via intermediates, such as p-nitrophenol, hydroquinone and hydroxylhydroquinone, by hydroxyl radicals (HO?) formed on the surface of GLTP.

    关键词: Liquid phase plasma,Gd-La codoped TiO2 photocatalysts,Band gap energy,Acetaminophen,Photocatalytic activity

    更新于2025-09-10 09:29:36

  • Study on the electrical, optical, structural, and morphological properties of highly transparent and conductive AZO thin films prepared near room temperature

    摘要: A correlation study between the microstructural, electrical, optical, and morphological properties of the highly transparent and conductive Al-doped ZnO (AZO) films of varying thickness deposited by 3D confined DC magnetron sputtering is reported. Incorporating a high-density plasma environment as indicated by plasma diagnostic it was possible to fabricate AZO films of resistivity as low as ~ 5.2×10-4 Ωcm and the maximum transmittance ~ 89 % with well crystalline structured and smooth morphology at low-temperature. Correlation among the film properties reveals the possibility of filling the Zn atom in the Zn vacancy could be responsible for preparing AZO thin film with improved microstructure and high enrichment of carrier mobility and concentration.

    关键词: AZO film,3-D confined magnetron sputtering,Transparent conducting oxide (TCO),Plasma processing

    更新于2025-09-10 09:29:36

  • Effect of hydrogen concentration on graphene synthesis using microwave-driven plasma-mediated methane cracking

    摘要: Gas phase graphene forms as an aerosol in a microwave plasma among other carbon forms. Consisting of 2-6 sheets per stack with dimensions between 100 – 500 nm, it is referred to as nanographene (NG). Surprisingly, increasing H/C ratio in the feedstock increases the relative graphitic content of the product. Dependence of the different carbon forms upon H/C ratio of the gas feed mixture is shown across multiple analytical characterizations. Attributes of (a) phase quality (pristine nature of NG) and (b) phase quantity (how much NG forms relative to other carbon sp2 phases) are addressed. Phase identification of the forms is performed via transmission electron microscopy with quantification by thermogravimetric analysis, assessing their respective oxidative reactivity benchmarked to commercially available similar carbon products applied as standards. X-ray diffraction differentiates these forms based on varied extent of graphitic structure. Electron energy loss spectroscopy assesses graphitic content by the ratio of sp2/sp3 bonding. Raman spectroscopy supports the observed shift in relative proportions of the carbon forms towards preferential graphitic content with increasing H/C. Selected area diffraction illustrates this for NG. Fringe analyses of nanostructure quantifies this shift for carbon particles. Infra-red spectroscopy reveals complementary C-H bonding as a measure of graphitic quality.

    关键词: electron energy loss spectroscopy,thermogravimetric analysis,hydrogen concentration,methane cracking,graphene synthesis,X-ray diffraction,nanographene,microwave-driven plasma,Raman spectroscopy,infra-red spectroscopy

    更新于2025-09-10 09:29:36

  • Cathode plasma electrolytic deposition of Al2O3 coatings doped with SiC particles

    摘要: Semiconductor particles doped Al2O3 coatings were prepared by cathode plasma electrolytic deposition in Al(NO3)3 electrolyte dispersed with SiC micro- and nano-particles (average particle sizes of 0.5–1.7 μm and 40 nm respectively). The effects of the concentrations and particle sizes of the SiC on the microstructures and tribological performances of the composite coatings were studied. In comparison with the case of dispersing with SiC microparticles, the dispersion of SiC nanoparticles in the coatings was more uniform. When the concentration of SiC nanoparticles was 5 g/L, the surface roughness of the composite coating was reduced by 63%, compared with that of the unmodified coating. Friction results demonstrated that the addition of 5 g/L SiC nanoparticles reduced the friction coefficient from 0.60 to 0.38 and decreased the wear volume under dry friction. The current density and bath voltage were measured to analyze the effects of SiC particles on the deposition process. The results showed that the SiC particles could alter the electrical behavior of the coatings during the deposition process, weaken the bombardment of the plasma, and improve the structures of the coatings.

    关键词: Cathode plasma electrolytic deposition,Surface roughness,Al2O3 coatings,SiC particles

    更新于2025-09-10 09:29:36

  • Stability-indicating micellar enhanced spectro-fluorometric determination of Daclatasvir in its tablet and spiked human plasma

    摘要: A fast, simple and sensitive micellar enhanced spectrofluorimetric method is performed for the determination of Daclatasvir dihydrochloride (DAC) in its pharmaceutical dosage form and in spiked human plasma. The fluorescence intensity (FI) was measured at 367 nm after excitation at 300 nm. In aqueous solution, the FI of DAC was greatly enhanced by more than 110% in the presence of sodium dodecyl sulphate (SDS). The detection method was linear over the range of 12.93 to 161.60 ng/mL, with a limit of detection of 1.75 ng/mL. The proposed method was successfully applied to the determination of DAC in its pharmaceutical dosage form and the mean % recovery of DAC in spiked human plasma was 95.42 + 2.52. The developed methodology was also extended to stress studies of DAC after exposure to different forced degradation conditions including acidic, alkaline, photolytic, thermal and oxidative environments.

    关键词: Spectrofluorimetry,Daclatasvir dihydrochloride (DAC) detection,spiked human plasma

    更新于2025-09-10 09:29:36

  • Design and analysis of electrostatic-charge plasma based dopingless IGZO vertical nanowire FET for ammonia gas sensing

    摘要: In this paper, Dopingless Gate All Around (GAA) Vertical Nanowire Field Effect Transistor (VNWFET) is designed with artificial material Indium Gallium Zinc Oxide (IGZO) as a channel material. IGZO channel has high electron mobility compared to more traditional amorphous semiconductors. In VNWFETs, since the channel length (Lch) is characterized vertically, it can be relaxed without area penalty on-chip, which in turn also allows some relaxation in the nanowire diameter while keeping optimum short-channel-effects control. Electrostatic-Charge Plasma technique is used to form a source-drain region on an intrinsic body of IGZO material. At the source side, the N+ region is formed by selecting the appropriate work function of the metal electrode, and at the drain side, the N+ region is formed by giving biasing to the metal electrode. N+ channel dopingless VNWFET with the catalytic metal gate is proposed for ammonia gas sensing. Cobalt, Molybdenum, and Ruthenium are used as a gate electrode in ammonia gas detection due to their high reactivity towards ammonia. Also, we have compared their ON and OFF sensitivity of the proposed device toward the gas adsorption. Due to the presence of gas on the gate, the metal work function of gate metal changes which varies the OFF-current (IOFF), ON-current (ION) and Threshold voltage (Vth) as these are considered as sensitivity parameters for sensing the ammonia gas molecules. The dimensional parameters (radius, and length) and dielectric materials are varied to check the change in device sensitivities. Results show that as the work function varies increases 50, 100, 150, 200meV and 250meV for catalytic metal at the gate, the sensitivity is increased.

    关键词: Vertical nanowire FET (VNWFET),Indium Gallium Zinc Oxide (IGZO),Electrostatic-Charge Plasma (E-CP),Ammonia Gas sensor

    更新于2025-09-10 09:29:36