Although micro-milling is a prevalent method for repairing micro-defects on KDP (KH2PO4) optical surfaces, the repaired areas are prone to brittle crack development, a consequence of KDP's inherent brittleness and softness. A conventional approach to assessing machined surface morphologies is surface roughness, yet this metric proves insufficient for directly differentiating between ductile-regime and brittle-regime machining processes. In order to reach this aim, the exploration of new evaluation methodologies is paramount to better describing machined surface morphologies. The fractal dimension (FD) was utilized in this study to evaluate the surface morphologies of KDP crystals, which were prepared via micro bell-end milling. Employing box-counting methods, the 3D and 2D fractal dimensions of the machined surfaces were determined, as were their typical cross-sectional contours. Subsequently, a thorough examination incorporating surface quality and texture analysis ensued. The 3D FD inversely correlates with surface roughness values (Sa and Sq), implying that surfaces with lower quality (Sa and Sq) possess smaller FD values. Surface roughness analysis fails to capture the anisotropy present in micro-milled surfaces, a property that can be quantified by employing the circumferential 2D finite difference approach. A characteristic symmetry of 2D FD and anisotropy is normally observed in micro ball-end milled surfaces created via ductile machining. Yet, if the 2D force field's distribution becomes asymmetrical, and the anisotropy weakens, the evaluated surface contours will display the presence of brittle cracks and fractures, leading to the corresponding machining procedures operating in a brittle manner. This fractal analysis will allow for a precise and effective evaluation of the repaired KDP optics after micro-milling.

Aluminum scandium nitride (Al1-xScxN) film's improved piezoelectric response has led to its increasing importance in micro-electromechanical system (MEMS) technology. A deep understanding of piezoelectricity hinges on an accurate measurement of the piezoelectric coefficient, which is indispensable for the design and fabrication of MEMS devices. learn more This study presents an in situ method for measuring the longitudinal piezoelectric constant d33 of Al1-xScxN films using a synchrotron X-ray diffraction (XRD) system. Lattice spacing alterations within Al1-xScxN films, in response to externally applied voltage, quantitatively demonstrated the piezoelectric effect, as evidenced by the measurement results. The accuracy of the extracted d33 was comparable to conventional high over-tone bulk acoustic resonators (HBAR) and Berlincourt methods. The in situ synchrotron XRD measurements and the Berlincourt method, when measuring d33, are subject to opposite errors: underestimation due to substrate clamping in the former and overestimation in the latter; correction of these errors is essential during the data extraction process. The d33 values of AlN and Al09Sc01N, measured synchronously using XRD, yielded 476 pC/N and 779 pC/N, respectively; these values corroborate well with results from the standard HBAR and Berlincourt procedures. Our research highlights the effectiveness of in situ synchrotron XRD in providing precise characterization of the piezoelectric coefficient d33.

The primary culprit behind the disconnection between steel pipes and core concrete during the building process is the shrinking of the concrete core. A significant approach to preventing voids between steel pipes and inner concrete, and enhancing the structural stability of concrete-filled steel tubes, involves the use of expansive agents during the cement hydration process. An investigation into the expansion and hydration characteristics of CaO, MgO, and CaO + MgO composite expansive agents within C60 concrete subjected to varying temperature conditions was undertaken. When designing composite expansive agents, the calcium-magnesium ratio's and magnesium oxide activity's effects on deformation are key considerations. Heating from 200°C to 720°C at 3°C/hour exhibited the dominant expansion effect of CaO expansive agents, while no expansion was detected during the cooling phase, spanning from 720°C to 300°C at 3°C/day and subsequently to 200°C at 7°C/hour. The cooling stage's expansion deformation was largely a consequence of the MgO expansive agent. The enhanced responsiveness of MgO during concrete heating led to a decrease in MgO hydration; correspondingly, MgO expansion expanded during the cooling phase. learn more 120-second and 220-second MgO samples demonstrated continuous expansion during the cooling phase, with the expansion curves failing to converge; in contrast, the 65-second MgO sample's reaction with water produced abundant brucite, resulting in diminished expansion deformation as the cooling progressed. To summarize, the CaO and 220s MgO composite expansive agent, when administered at the correct dosage, effectively compensates for concrete shrinkage during rapid high-temperature increases and slow cooling phases. This study will illustrate the use of various CaO-MgO composite expansive agents within concrete-filled steel tube structures facing challenging environmental factors.

Roofing sheets' exterior organic coatings' strength and dependability are critically assessed in this document. The research selected two sheets: ZA200 and S220GD. These sheets' metallic surfaces are shielded from the damaging effects of weather, assembly, and operation by a multi-layered organic coating system. Durability testing of these coatings involved assessing their resistance to tribological wear, employing the ball-on-disc method. Testing, with reversible gear, was carried out along a sinuous trajectory, with the cadence maintained at 3 Hz. A 5-newton test load was applied. A scratch on the coating allowed the metallic counter-sample to contact the roofing sheet's metallic surface, a clear sign of a substantial decrease in electrical resistance. The number of cycles completed is believed to be an indicator of the coating's durability. To scrutinize the findings, a Weibull analysis was employed. A determination of the tested coatings' reliability was made. Testing has definitively established the coating's structure as a key factor in the products' endurance and trustworthiness. Crucial discoveries are detailed in this paper's research and analysis.

AlN-based 5G RF filters' operation relies heavily on the piezoelectric and elastic properties for optimal performance. The improvement of the piezoelectric response in AlN is often linked to a reduction in lattice firmness, which impacts the elastic modulus and sound velocities negatively. The simultaneous optimization of piezoelectric and elastic properties is both challenging and represents a significant practical advantage. The investigation of 117 X0125Y0125Al075N compounds in this work was facilitated by high-throughput first-principles calculations. High C33 values, greater than 249592 GPa, and high e33 values, exceeding 1869 C/m2, were observed in B0125Er0125Al075N, Mg0125Ti0125Al075N, and Be0125Ce0125Al075N. A COMSOL Multiphysics simulation indicated that the quality factor (Qr) and effective coupling coefficient (Keff2) of resonators made from these three materials were superior to those with Sc025AlN, with the exception of Be0125Ce0125AlN, which had a lower Keff2 due to a higher permittivity. The enhancement of the piezoelectric strain constant in AlN, achieved through double-element doping, is evident in this result without any accompanying lattice softening. Doping elements, featuring d-/f-electrons and significant internal atomic coordinate modifications of du/d, contribute to the attainment of a substantial e33. Nitrogen bonds with doping elements exhibiting a smaller electronegativity difference (Ed), thus yielding a greater elastic constant, C33.

Single-crystal planes, as ideal platforms, are well-suited for catalytic research. Initiating this work, rolled copper foils, with a principal (220) planar orientation, were employed The process of temperature gradient annealing, promoting grain recrystallization in the foils, resulted in the transformation of the foils to exhibit (200) planes. learn more A 136 mV lower overpotential was observed for a foil (10 mA cm-2) subjected to acidic conditions, in comparison to a similar rolled copper foil. The calculation results suggest that hollow sites on the (200) plane possess the greatest hydrogen adsorption energy and are active centers for catalyzing hydrogen evolution. This study, therefore, illuminates the catalytic activity of particular sites on the copper surface and reveals the pivotal role of surface engineering in determining catalytic attributes.

Currently, intensive research is dedicated to the creation of persistent phosphors emitting light that surpasses the visible range. In several emerging applications, consistent emission of high-energy photons is a necessity; however, appropriate materials for the shortwave ultraviolet (UV-C) region are exceptionally scarce. A novel UV-C persistent luminescence phosphor, Sr2MgSi2O7 doped with Pr3+ ions, is reported in this study, exhibiting a maximum intensity at 243 nm. By means of X-ray diffraction (XRD), the solubility of Pr3+ within the matrix is investigated, and the optimal concentration for the activator is subsequently determined. Photoluminescence (PL), thermally stimulated luminescence (TSL), and electron paramagnetic resonance (EPR) spectroscopic analysis are used to determine the optical and structural properties. Outcomes from the experiment widen the class of UV-C persistent phosphors and provide novel elucidations of the mechanisms of persistent luminescence.

This work is driven by the need to discover the most effective methods of bonding composites, with particular emphasis on aeronautical uses. To characterize the impact of varying mechanical fastener types on the static strength of composite lap joints and on the failure mechanisms of such joints when subjected to fatigue loading was the goal of this study.