- 标题
- 摘要
- 关键词
- 实验方案
- 产品
-
Impact of surface micromorphology and demineralization severity on enamel loss measurements by cross-polarization optical coherence tomography
摘要： Objectives: Optical Coherence tomography (OCT) is a promising clinical imaging technology for quantitative and objective assessment of dental erosion. We aimed to determine the influence of enamel surface roughness and demineralization severity (by erosive challenge) on dental surface loss measurements by cross-polarization OCT (CP-OCT). Materials and methods: Human enamel specimens were prepared with three surface roughness levels (very rough, rough and polished; n = 10 each). They were evaluated using CP-OCT and optical profilometry (gold standard) at baseline, and after 1, 2, 4, 6, 8, 16 and 24 h of erosion demineralization. The effects of roughness and demineralization on enamel loss were analyzed using ANOVA (alpha = 0.05). Intraclass correlation coefficients (ICCs) and Bland-Altman plots were used to evaluate inter-method agreement and intra-examiner repeatability. Results: CP-OCT surface loss measurements did not significantly differ with the changes in enamel surface roughness (p = 0.27). Among demineralization severities, CP-OCT surface loss measurements at 1, 2, 4 and 8 h did not differ among each other, but they showed significantly lower enamel loss than 16 and 24 h; 6 and 16 h were significantly lower than 24 h (p < 0.05). Overall, CP-OCT and optical profilometry measurements did not differ (p = 0.73); however, ICC was relatively low (ICC = 0.34). Enamel loss estimation by CP-OCT presented an error of approximately ± 150 μm compared to profilometry. Intra-examiner repeatability with CP-OCT was excellent (ICC = 0.98). Conclusions: Enamel roughness did not affect CP-OCT measurements. The estimated error of CP-OCT measurements limited the appropriate assessment of enamel erosion surface loss, in the magnitude simulated in this study. Clinical relevance: Enamel thickness measurement by CP-OCT presents potential as an objective method for monitoring dental erosion lesions; however, its use may be limited for the assessment of the initial stages of enamel surface loss by erosion.
关键词： Tooth wear,Optical coherence tomography,Surface roughness,Enamel,Dental erosion,Demineralization
更新于2025-09-23 15:23:52
-
Theory for IMPS on Rough and Finite Fractal Dye Sensitized Solar?Cell
摘要： A generalized theoretical model of intensity modulated photocurrent spectroscopy (IMPS) for the random morphology in a dye sensitized solar cell (DSSC) under uniform illumination is developed. The generalized IMPS expression for the disordered semiconducting/conducting glass interface of a DSSC is obtained in term of power spectral density of roughness. Influence of surface roughness on the dynamic response of DSSC originate due to the coupling of characteristic phenomenological and morphological length scales. A detailed analysis of IMPS response is performed over finite self-affine fractals to highlight roughness induced anomalies and cause of photocurrent enhancement. The IMPS of a rough DSSC exhibit three characteristic frequency regimes: lifetime of charge carrier dependent low frequency regime, surface irregularity dependent intermediate power-law regime and diffusion controlled high frequency regime. Finally, our theory facilitates the understanding of dynamics and kinetics of charge carriers under the influence of ubiquitous surface disorder.
关键词： DSSC,charge transport,fractal,surface roughness,IMPS
更新于2025-09-23 15:23:52
-
Formation of 45° Silicon (110) Surface Using Triton X- <i>n</i> Surfactants in Potassium Hydroxide for Infrared Applications
摘要： Silicon (Si) micromirrors are an integral feature for many micro-optomechanical systems (MOEMS). Such mirrors are generally wet etched in alkaline solution at elevated temperature. For 90? beam steering applications, 45? slanted Si (110) plane is the prime choice fabricated with the incorporation of tensioactive surfactants. Here, Triton-Si and Triton-hydroxide (OH?)/H2O interaction using varying hydrophilic chain length Triton (X-45, X-100 and X-405) were investigated. The surfactant concentration was varied from 0 to 1000 ppm in potassium hydroxide (KOH). Triton molecules were shown to adsorb preferentially on (110) than on (100) surface. Longer chain length Triton hampered OH? access to Si surface resulting in slower etch rate. In contrast, contact angle measurement suggested that shorter Triton interfaced better with Si surface. Later, Si wafers etched in Triton 10 ppm – KOH were examined. The measured output for (110)X-45, (110)X-100, (110)X-405 and polished Si wafer reference (Rq < 5?) mirrors were 0.58, 0.76, 0.72 and 1.25 mW, respectively. Subsequently, Si-SiO2 thin film in [HLHL]2-substrate configuration was fabricated. Broadband micromirror for use in 3.0–5.5 μm spectrum range was experimentally realized with reflected efficiency of 73%.
关键词： wet etching,optical measurement,Silicon micromirrors,Triton X-n,surface roughness,potassium hydroxide,surfactants
更新于2025-09-23 15:23:52
-
Characteristics of Vanadium Oxide Thin Films Fabricated by Unbalanced Magnetron Sputtering for Smart Window Application
摘要： Vanadium oxide (VOx) thin films were deposited by an unbalanced magnetron (UBM) sputtering system with a vanadium metal target and O2 reaction gas, and thermally treated at various annealing temperatures. In this work, the structural, electrical, and optical properties of the fabricated VOx films with various annealing temperatures were experimentally investigated. The UBM sputter grown VOx thin films exhibited amorphous structure, and had a very weak peak of V2O5 (002) owing to very thin films. However, the crystallite size of VOx films increased with increasing annealing temperature. The surface roughness of VOx films and average transmittance decreased with increasing annealing temperature. The resistivity of VOx films also decreased with increasing annealing temperature, while the electrical properties of films improved.
关键词： Transmittance,Unbalanced Magnetron Sputtering,Vanadium Oxide,Surface Roughness,Resistivity
更新于2025-09-23 15:23:52
-
Realizing Q> 300 000 in diamond microdisks for optomechanics via etch optimization
摘要： Nanophotonic structures in single–crystal diamond (SCD) that simultaneously con?ne and co-localize photons and phonons are highly desirable for applications in quantum information science and optomechanics. Here we describe an optimized process for etching SCD microdisk structures designed for optomechanics applications. This process allows the optical quality factor, Q, of these devices to be enhanced by a factor of 4 over previous demonstrations to Q ～ 335 000, which is suf?cient to enable sideband resolved coherent cavity optomechanical experiments. Through analysis of optical loss and backscattering rates, we ?nd that Q remains limited by surface imperfections. We also describe a technique for altering microdisk pedestal geometry which could enable reductions in mechanical dissipation.
关键词： surface roughness,optomechanics,quality factor,etch optimization,diamond microdisks
更新于2025-09-23 15:23:52
-
Modeling and multiresponse optimization of cutting parameters in SPDT of a rigid contact lens polymer using RSM and desirability function
摘要： Amidst different conventional contact lens manufacturing techniques, single-point diamond turning (SPDT) is one of the recently developed ultra-high precision machining techniques employed in the fabrication of advanced contact lenses due to its capability of producing high optical surfaces of complex shapes and nanometric accuracy. SPDT is regarded as an effective process for the generation of high-quality functional surfaces in optical industries. However, despite advances in the ultra-high precision machining, it is not always easy to achieve a high-quality surface finish with maximum productivity. Machining parameters, namely cutting speed, feed rate, and depth of cut, play the lead role in determining the machine economics and quality of machining. The present study focuses on the determination of the optimum cutting conditions leading to minimum surface roughness as well as electrostatic charge and maximum productivity, in SPDT of the polymethyl methacrylate (PMMA) contact lens polymer using monocrystalline diamond cutting tool. The optimization is based on the response surface methodology (RSM) together with the desirability function approach. In addition, a mathematical model is developed for surface roughness (Ra), electrostatic charge (ESC), and material removal rate (MRR) using RSM regression analysis for a rigid contact lens polymer by the Design-Expert software. RSM allowed the optimization of the cutting conditions for minimal surface roughness, electrostatic charge, and maximal material removal rate which provides an effective knowledge base for process parameters, to make its enhancement of process performance in SPDT of contact lens polymer.
关键词： Electrostatic charge,Response surface methodology,Material removal rate,Surface roughness and optimization,PMMA contact lens polymer,Single-point diamond turning
更新于2025-09-23 15:22:29
-
Novel polyelectrolyte–Al2O3/SiO2 composite nanoabrasives for improved chemical mechanical polishing (CMP) of sapphire
摘要： A new type of polyelectrolyte–Al2O3/SiO2 composite nanoparticle with excellent dispersibility and superior polishing performance was successfully fabricated using a facile method. Silica acted as a bifunctional molecule by attaching to alumina via covalent bond and adsorbing polyelectrolytes by electrostatic interaction. The material removal rate of the polyelectrolyte–Al2O3/SiO2 abrasive was 30% higher than that of the pure Al2O3 abrasive. In addition, the sapphire surface was much smoother. The material removal mechanism was investigated during CMP using the microcontact and wear model. The enhanced removal rate was mainly attributed to the well-dispersed particles, which can accelerate mechanical removal process. The remarkably smooth surface was due to the decrease in penetration depth of the abrasive into the wafer. The results of this study provided a feasible strategy to satisfy the high efficiency and damage-free polishing requirements for sapphire planarization.
关键词： chemical mechanical polishing,composite abrasives,polyelectrolyte,surface roughness,sapphire,material removal rate
更新于2025-09-23 15:22:29
-
Highly Hydrophobic Conducting Nanocomposites Based on a Fluoropolymer with Carbon Nanotubes
摘要： A procedure was suggested for preparing highly hydrophobic conducting coatings based on fluoropolymers with carbon nanotubes of two types: Taunit-MD and carbon nanotubes functionalized with alkyl groups. The surface resistance, contact angle, sliding angle, and surface roughness were measured; structural features of the nanocomposites were studied. The properties of the coatings obtained depend on the concentration and type of the carbon nanotubes used. Introduction of functionalized carbon nanotubes into a fluoropolymer matrix allows preparation of coatings with higher values of the sliding angle and electrical resistance. The contact angle and sliding angle depend on the surface roughness and structure in different fashions.
关键词： carbon nanotubes,electrical conductivity,surface roughness,hydrophobicity,nanocomposites
更新于2025-09-23 15:22:29
-
White light interferometry and MountainsMap? - case studies in static load capacity of bearings and surface finish optimisation of orthotic knee joints
摘要： This paper deals with two case studies demonstrating the combined use of white light interferometry and MountainsMap? software to: 1) accurately measure indentation diameters on race elements with an accuracy of a 1/100th of a micrometer and to examine static load capacity of bearings compared to the industry standard. In this case study, static load capacity of the ball bearings was shown to be 31% lower than that specified by ISO and ANSI/ABMA bearing standards; 2) characterise machined surfaces with 2D and 3D parameters, with the goal of producing optimal surface finish on orthotic knee joints used by Cerebral Palsy patients. In this case study, 2D roughness parameters Ra, Rq, Rp, Rz, and 3D roughness parameters Sa, Sq, Sp, Sz, were improved by 34%, 31%, 8%, 20%, and 36%, 33%, 6%, 6% respectively. Both case studies demonstrate the significance of modern topography techniques in enhancing the measurement accuracy of surface characteristics.
关键词： robust design,MountainsMap?,surface roughness,signal-to-noise (S/N) ratio,interferometry,WLI,static load capacity,white light,ball bearing indentations
更新于2025-09-23 15:22:29
-
Experimental Optimization of Annular Polishing Parameters for Silicon Carbide
摘要： Machined surface quality has a strong impact on the functionality of silicon carbide-based components and devices. In the present work, we ?rst analytically investigate the complex coupling of motions in annular polishing based on the Preston equation, which derives the in?uential parameters for material removal. Subsequently, we conduct systematic annular polishing experiments of reaction-bonded silicon carbide to investigate the in?uence of derived parameters on polished surface quality, which yield optimized polishing parameters for achieving ultralow surface roughness of reaction-bonded silicon carbide.
关键词： silicon carbide,polishing parameters,annular polishing,Preston equation,surface roughness
更新于2025-09-23 15:21:21