Silicon最新文献

In recent years, the extensive use of organic dyes has caused great pollution to the water environment. Zinc silicate with excellent adsorption and photocatalytic properties has been widely used in the treatment of organic dye wastewater. Therefore, we successfully prepared zinc silicate nanomaterials by simple hydrothermal method using zinc sulfate heptahydrate (ZnSO₄·7H₂O) and tetraethyl orthosilicate (TEOS) as raw materials, and cetyltrimethylammonium bromide (CTAB) as surfactant, and applied them to the treatment of organic dye wastewater. The composition, morphology and specific surface area of zinc silicate nanomaterials were characterized by X-ray diffraction (XRD), Fourier transform infrared spectroscopy (FTIR), field emission scanning electron microscopy (FESEM), and Brunauer–Emmett–Teller (BET) method. The results show that the phase composition of the products has a transformation from hemimorphite Zn₄Si₂O₇(OH)₂·H₂O to vermiculite Zn₂SiO₄, and the morphology has also an obvious change from nanosheets, nanoflowers to nanoparticles with the increase of TEOS content. The specific surface area and pore volume are 199.8 m²/g and 0.441 cm³/g for the flower-like zinc silicate nanomaterials. The zinc silicate nanomaterials show excellent adsorption and photocatalytic properties for organic dyes from aqueous solutions, and the maximum removal efficiencies can reach 89.8% and 96.2% for rhodamine B (RhB) and methylene blue (MB), respectively.

Porous silicon (Psi) has recently attracted considerable attention because of its unique optical and structural properties and capacity to be used in various applications. Due to the importance of this material, we have investigated the infiltration of trivalent erbium ions (Er³⁺) into silicon-generated pores using the electrochemical approach. The infiltration of Er³⁺ ions will be done simultaneously with the forming of porous silicon films on p-type (100) silicon substrates. Generating the porous layer can improve the evenness and integration of Er inside the material. During infiltration, Er³⁺ ions can also undergo reduction or co-deposition with other elements at the cathode. The infiltration studies were conducted while subject to the influence of the current density (15–30 mA/cm²). The results showed that the emission of photoluminescence in porous silicon filled with erbium was caused by the presence of Er silicate and Er oxide that developed within the silicon pores during the electrochemical reaction. The reason for introducing rare earth ions is their exceptional optical characteristics, encompassing distinct emission lines and extended lifespan. We comprehensively investigate infiltration and outline the electrochemical etching parameters necessary to create porous silicon. Rare earth ions exhibit exceptional optical luminescence characteristics, displaying a diverse spectrum of optical spectra over the infrared, visible, and ultraviolet regions.

Lead (II) oxide (PbO) has shown high prospect in modifying mechanical, physical, neutron and charge particle interaction properties of geopolymer due to high bonding matrix. In this study, the impact of PbO doping on the microstructure, mechanical strength, neutron and charge particles interaction properties of geopolymer composites was examined. The undoped and doped geopolymer powders were produced and sintered above 1100 °C for 1 h to obtain denser materials. The X-ray diffraction (XRD) analysis showed that the material is rich in cristobalite (C), mullite (M), and lead silicate (P) phases. The EDS analysis of geopolymer gave Si, O, Na and Al with 40.87, 35.37, 6.06 and 17.68% wt respectively as major elements. The Vickers hardness (HV) values for GEO, GEO-10Pb and GEO-20Pb samples were obtained as 595, 647 and 682 HV respectively under 0.5 kg load. The showed that the introduction of 10% and 20% PbO significantly improved the charge particle attenuation, density and Vickers Hardness of the geopolymer while the total fast neutron removal cross-section decreases with increasing lead content.

We investigate the influence of spin and impurity on the density of states of SiC nanotubes employing Density Functional Theory (DFT) and a Machine Learning (ML) based framework. Our study investigates the electronic structures and magnetic properties of various SiC nanotube configurations, including wurtzite, Co-doped, and undoped single-wall (6,0) chiral nanotubes, employing both DFT and pseudopotential approaches. The calculated energy band gap values for SiC bulk structures, nanotubes, and doped systems, retaining local density and local spin density approximations with the Hubbard U method, exhibit distinct characteristics. While undoped SiC systems remain nonmagnetic whereas Co-doped SiC systems show magnetic properties, with a total magnetic moment of around ~ 1.9 µB. Our first-principles calculations indicate that Co-doped SiC nanotubes induce magnetism, however the total energy calculations revealed satisfactory stability for the ferromagnetic phase. Validation against DFT data demonstrates that our model achieves approximately 91.5% accuracy for predicting the density of states for quantum-confined SiC nanotube structures and also showcasing significant potential for further electronic properties calculations in this domain. Integrating ML algorithms with DFT-based approach presents an efficient algorithm for predicting total density of states in quantum-confined nanoscale structures. The fine tree regression algorithm shows highly efficient and effective prediction for density of states calculations.

A new hybrid finishing process, namely, double-disc chemical-assisted magnetorheological finishing (DDCAMRF) process has been developed for the polishing of monocrystalline silicon wafers combining the benefits of the two processes namely, chemical–mechanical polishing (CMP) and magneto-rheological finishing (MRF). In the present work, the bonding between the Si atoms gets weakened by the chemical action which further softens the work surface while the rotation of MR fluid provides the desired mechanical force which assists in the removal of material from the work surface. An experimental setup for the hybrid finishing has been designed and fabricated for achieving the nanometric finishing of silicon substrates. Also, the process was further established by carrying out the experimental study which involves analyzing the influence of different process factors viz., polishing speed, % CIP concentration, slurry flow rate, and working gap, on the surface roughness (R_a) of a monocrystalline silicon wafer. An improvement of over 88.96% was observed in the surface roughness of a silicon wafer and a nearly mirror-like finish was observed while carrying out the polishing with the developed DDCAMRF process. The developed process resulted in enhancing the process performance ensuring better surface finish (i.e., with minimal defects) and reduced polishing time compared to different polishing techniques available.

Development an advanced drug delivery biocomposite beads using polyvinylpyrrolidone, Sodium Alginate, and bioglass as a carrier for 20% amoxicillin drug. The two beads’ samples were formed by the sol–gel process combined with the dropwise method, through exposure to simulated body fluid (SBF). The obtained beads were assessed by XRD, SEM, and FT-IR confirming the in vitro test. The spectroscopic results confirm their successful development of the apatite layer. The SEM shows that the bio-beads are microsphere structures with a diameter from 405 nm to 4.700 μm. UV/visible diffuse reflectance analysis assessed the impact of loading amoxicillin on optical properties and determined the energy gap (Eg) for the composites, yielding values of 1.25 and 2.59 eV for the direct and indirect transitions. The antimicrobial efficiency is evaluated by employing the agar diffusion method with a range of pathogenic microorganisms. Staphylococcus aureus, Staphylococcus haemolyticus, and Enterococcus faecalis are used as senates for the + ve bacteria, whereas Klebsiella pneumoniae and Escherichia coli as -ve bacteria. The SBF tests confirm apatite covering on the bead surfaces, representative of effective bioactivity. Antimicrobial results establish enhanced performance, signifying the two bio-bead samples as promising applicants for bone tissue engineering.

This research is essential for the progress of nanocomposite technology, with ramifications for society. The development of economical and high-performing nanocomposites may result in improved and adaptable optoelectronic devices, therefore contributing to technical progress and economic advantages. The (PMMA-SiO₂/CuO) nanocomposites(NCs) have been prepared using the solution cast method. This study examined the structural, optical, and electrical characteristics of nanocomposites consisting of PMMA-SiO₂/CuO. The nanoparticles were uniformly distributed throughout the composite, resulting in a cohesive network within the polymer matrix, as evidenced by the optical microscope photos. The FTIR analysis showed a shift in the peak location and changes in the shape and intensity compared to the pure PMMA sample. The findings about the optical characteristics indicate a significant increase in absorption by approximately 331% (from 0.65 to 2.77) at a wavelength of 520 nm. The absorbance, refractive index, and optical conductivity of pure PMMA exhibited an increase with the rising concentration of (SiO₂/CuO) nanoparticles. Additionally, the energy gap experienced a decrease of roughly 120% (from 4.01 to 1.81 eV) for allowed indirect transitions and 248% (from 3.48 to 1.05 eV) for forbidden indirect transitions with increasing concentration of (SiO₂/CuO) nanoparticles. The nanocomposites of PMMA-SiO₂/CuO exhibit a significant absorbance level in the ultraviolet (UV) region. As the frequency of the applied electric field increased, the dielectric constant and dielectric loss of the (PMMA-SiO₂/CuO) nanocomposites decreased, as indicated by the experimental results. With an increase in frequency, the electrical conductivity of an alternating current (A.C.) increases. The dielectric loss of pure PMMA exhibited an increase with the increasing concentration of (PMMA-SiO₂/CuO) nanoparticles. At a frequency of 100 Hz, the presence of SiO₂/CuO nanoparticles in PMMA increased the dielectric constant by about 44% and the A.C. electrical conductivity by approximately 328% when the nanoparticles accounted for 6% of the total weight. The pressure sensor application investigation findings on NCs demonstrate a direct correlation between the applied pressure and the rise in electrical capacitance (C_p).

Arsenic (As) threatens plant growth and human health because its harmful effects are intensified by its persistent presence in the ecosystem. The absorption of As from the contaminated soil leads to accumulation in grains of food crops posing a serious threat to human health. High concentration of As hindered essential physio-biochemical processes of plants that ultimately diminish the growth and yield of crops. Therefore; a pot study was designed to assess synergistic effect of silicon (Si) and salicylic acid (SA) (control-Ck, 4.0 mM Si, 150 µM SA, 4.0 mM Si + 150 µM SA) in mitigating the adversities of As stress in wheat seedlings exposed to As stress (0, and 100 μM). Wheat seedlings exposed to As showed a significant decline in morphological attributes as well as photosynthetic pigments (chlorophyll a, b and carotenoids). However; foliar application of Si and SA considerably increased morphological parameters and leaf photosynthetic pigments under As stress. The imposition of As resulted in enhance accumulation of hydrogen peroxide, MDA, and electrolyte leakage, increased activities of enzymatic antioxidants (superoxide dismutase, peroxidase, and ascorbate peroxidase and catalase) and an elevated accumulation of essential organic osmolytes (free proline, soluble protein, total soluble sugar, total phenolics) in leaves of wheat seedlings. Furthermore, the application of Si + SA resulted in a remarkable increase in the activities of enzymatic antioxidants and accumulation of organic osmolytes. Simultaneously, it reduced the concentration of hydrogen peroxide, MDA, and electrolyte leakage in As-stress wheat seedlings. Under As-stress, sole and combined application of Si and SA caused a significant reduction in arsenic concentration while enhance Si contents in root and shoot of wheat seedlings. In conclusion, synergistic interaction between Si and SA could alleviate the negative impact of As by enhancing the antioxidant defense system, photosynthetic pigments, facilitating osmotic adjustment, and reducing the lipid peroxidation in maize seedlings. The current findings suggest that the combined exogenous application of Si and SA represent a promising approach for promoting the successful cultivation of wheat in As contaminated soil.

Graphical Abstract

A five pressured diatomite clay materials samples were produced as a mixture of diatomaceous earth mineral and sodium silicate for the purpose of this investigation. The forming pressures ranged from 22.84 MPa to 114.24 MPa, and the samples were formed under a variety of conditions. The ratio of Na₂SiO₃ to the total mass of the produced pressed samples was maintained at precisely 15 wt.% throughout the process. Through the process of increasing the forming pressure, the density of the pressed samples was increased by ~ 11%. For the purpose of determining how the forming pressure will affect the shielding capacity, the Monte Carlo simulation was applied. The linear attenuation of the fabricated pressed diatomite samples improves from 0.123 to 0.136 cm⁻¹ when the forming pressure is increased from 22.84 MPa to 114.24 MPa. By increasing the pressure from 22.84 MPa to 114.24 MPa, the half-value thickness reduced from 5.63 cm to 5.09 cm, and the thickness equivalent = 1 cm of pure Pb metal decreased from 10.09 cm to 9.12 cm. It was found that elevating the forming pressure resulted in an augmentation of the fast neutron removal for the artificially manufactured pressed diatomite samples.

In this study, highly ordered mesoporous silica (SBA-16) were synthesized by a one-step sol–gel method, relating to the interaction with the self-assembly of the non-ionic surfactant, pluronic F127 under an acidic condition without the hydrothermal process. SBA-16 was further incorporated with titanium dioxide (TiO₂) with varied Si/Ti ratios (11.2, 2.8 and 0.7) to optimize a suitable condition for producing SBA-16/TiO₂ composites. After calcination, the composites were characterized by using various techniques to evaluate pore characteristics, morphologies and phase present. Typically, the highly ordered porous structure of the synthesized SBA-16 was confirmed by low angle X-ray analysis (LAXRD) and N₂ adsorption isotherms. TiO₂ nanoparticles were found at the surfaces of SBA-16 of each composite based on the HR-TEM images. Diuron herbicide in aqueous solutions (50 ppm of the initial concentration) was used as a polluted model for studying on the photocatalytic activity of the composites under an artificial UV illumination for 24 h. Experimental results revealed that SBA-16 could assist on diuron reduction in the dark condition by the adsorption process. Diuron in the solutions were fully degraded by the synthesized TiO₂ and the SBA-16/TiO₂ composite (0.7 Si/Ti ratio) within 24 h of the UV illumination. In addition, it revealed that SBA-16 could assist on diuron reduction in the dark condition by the adsorption process. The degradation was calculated and followed to the first order kinetic model. Finally, a mechanism of the degradation was discussed and proposed.