Sanchezblevins3047

This study aimed to evaluate the soundness of solid-state welded steels. STS 430F alloy with a rod type was selected as experimental material, and the friction welding was conducted at a rotation speed of 2,000 RPM and upset length of 3 mm. The application of friction welding on STS 430F rods led to significant grain refinement in the welded zone (1.3 µm) compared to that observed in the base material (16.8 µm). The refined grains in the welds contributed to the development of the mechanical properties. In particular, the Vickers microhardness was increased by approximately 25% compared to the base material, and the fracture at the tensile specimen of the welds occurred at the base material zone and not in the welded zone, which suggests a soundly welded state on the STS 430F rods.Anatase-type one-dimensional TiO₂ nanowire was prepared by hydrothermal method. The nanowires were modified by three kinds of silane coupling agents, such as KH550, KH560 and KH570. Flocculation was caused when the amount of modifier reached a certain level. When KH570 was used at 3.0 percent, at 80 °C, 4 h, and pH value between 9 and 10, modified nanowires had the highest 56.5 percent lipophilization degree, the lowest 0.562 per/nm² surface hydroxyl number, and the maximal 121.2° static contact angle.Noble metal-metal oxide nanohybrids play a significant contribution in gas sensing applications at room temperature. Here, Ag-loaded ZnO with different Ag doping concentration are prepared by two-step polymer-network gel method, and NO₂ sensing characteristics are tested at room temperature with various concentrations. The nanocrystal sizes are found to be more uniform with increasing with Ag concentration, and photoluminescence spectroscopy further reveals the different defects in ZnO-Ag nanocrystal lattices pure ZnO has the largest intensity of the conduction band to valence band combination, and ZnO-Ag-1 (1 mol% Ag doping concentration) has the largest oxygen vacancy content, while ZnO-Ag-3 (3 mol% Ag doping concentration) has the largest excess zinc interstitial. It is showed that the gas sensing properties are independent of the size of nanocrystals, and more dependent on the nanocrystal defect structure. In this work, a new sensing mechanism is proposed according to the experimental results.For painless skin penetration, microneedles require optimal geometry due to human skin's inherent elastic properties. The fabrication of desired shape microneedle is very critical. To our knowledge, the polygonal geometry microneedle has not been investigated before. To address this issue, in this communication, we propose a novel cleanroom free fabrication of single metal microneedle with square cross section. The microneedle was fabricated using sputtering technique without any mask or template. The morphological analysis with respect to various sputtering parameters via. Argon (Ar) pipe position, rotating speed, working pressure was discussed in detail. The microneedle geometry, its assisted pain was visualized using finite element analysis (FEM). The theoretical evaluations were subsequently compared with experimentally fabricated microneedle. This is the first step towards more rational design of polygonal microneedle geometry.Flexible in-plane gate SnO₂ nanowire (NW) transistor gated by SiO₂ acting as a solid electrolyte was fabricated on a paper substrate by using a transmission electron microscopy (TEM) Ni grid shadow mask. The operating voltage of in-plane gate SnO₂ NW transistor was down to 1 V because of the large electric-double-layer (EDL) capacitance of the SiO₂ electrolyte layer. find more Current on/off ratio (Ion/Ioff) and field-effect electron mobility (µEF) as well as subthreshold slope of this device were ~106, 74.7cm²·V-1s-1 and 80 mV·dec-1, respectively. The proposed flexible and low-voltage SnO₂ NW transistors on paper substrate exhibit immense potential for applications in portable and flexible electronic devices.The fabrication of inexpensive nano-gaps is vitally important for the research and application of nanochannel-based devices. This study presents a low-cost and simple method for the fabrication of nano-gaps using thermal evaporation and stripping techniques. The structural morphology of metal films deposited on the convex structures of photoresist by sputtering and thermal evaporation was studied. The effect of angles of thermal evaporation on the width of nano-gaps was investigated. The characteristics of metal film deposited on the convex structures of photoresist and spaces between these convex structures after stripping were investigated, and the adhesive force between the metal film and silicon substrate was also analyzed. Finally, a metal film of Cu was deposited on the convex structures of photoresist by thermal evaporation. After stripping, nano-gaps with a width of 187 nm were fabricated. The method proposed in this paper can be employed to mass-produce two-dimensional nanochannels based devices at low cost.Birnessite-MnO₂ nanoflakes were synthesized via an aqueous oxidation method at 90 °C using Mn(CH₃COO)₂, NaOH, and KMnO₄. The samples' morphology, crystalline structure, and optical property were determined by field emission scanning electron microscopy, X-ray powder diffraction and UV-Vis spectrophotometry. The birnessite-MnO₂ nanoflakes were converted to K x Mn8O16 and Mn suboxides following a decrease in the concentration of KMnO₄ in the reaction. The amount of NaOH in the reaction determined the type of precursor. Without NaOH, the precursor was converted from Mn(OH)₂ to Mn2+ (from Mn(CH₃COO)₂), thereby enabling the synthesis of birnessite-MnO₂ nanoflowers. The formation mechanism of birnessite-MnO₂ nanoflowers and nanoflakes was clarified via the corresponding simulated crystal structures. Evaluation of the synthesized samples confirmed that the birnessite-MnO₂ nanoflakes and nanoflowers exhibited excellent degradation properties.The new wood-plastic nanocomposites (WPC) based on acrylonitrile-butadiene-styrene (ABS) resin was successfully blended with ABS and poplar flour (PF) through a HAAKE rheomix. The mechanical properties of nanocomposites, except for flexural modulus, were reduced after increasing the PF content. SEM photos show the reduction resulting from weak interfacial adhesion between the PF phase and ABS phase. Higher PF content leads to a low thermal stability and a high water absorption ratio. Different coupling agents (CA) were employed to improve the compatibility between PF and ABS. The results suggest that ABS-g-MAH is more effective than POE-g-MAH, EVA and SEBS. Maleic anhydride (MA) was blended in situ with PF and ABS as the reactive compatibilizer and mechanical properties of nanocomposites were improved except impact strength.