Root Mean Square Surface Research Articles

Thermal annealing effect on the electrical quality of graphene/hexagonal boron nitride heterostructure devices

The development of the dry transfer method provides an abundant platform to construct various heterostructures of two-dimensional materials. However, the surface and interface cleanliness are essential to realize high electronical performance of heterostructures devices. Here, we demonstrated thermal annealing effect on the mobility and electrical transport properties of graphene on hexagonal boron nitride heterostructures devices. With different annealing temperature recipes for graphene on hexagonal boron nitride devices, we found annealing temperature at 300 °C can clean resist residual and achieve high mobility. Atomic force microscopy results also present a clean surface and small average root mean square roughness as low as 210 pm. Well defined oscillations and plateaus of electrical transport at low magnetic field indicate a high-quality graphene surface.

Effect of resin infiltration application on early proximal caries lesions in vitro

Background/purposeResin infiltration (RI) material ICON is used in treating early proximal caries lesions, as it depends on a micro–invasive infiltration technology. This in vitro study aimed to evaluate the effect of ICON resin infiltration (RI) on early proximal caries by comparing surface roughness and hardness before and after treatment with RI using atomic force microscopy (AFM), automated microhardness testing system (AMHTS), and scanning electron microscopy (SEM) in vitro. Materials and methodsTwenty seven premolars extracted for orthodontic reasons were sectioned buccolingually, creating 54 specimens. Each specimen was immersed in demineralizing solution to induce caries. Only teeth with “International Caries Detection and Assessment System” codes 1 and 2 were selected. The specimens were divided randomly into either AFM, AMHTS or SEM groups, which examined demineralized enamel before and after treatment with ICON. ResultsThe mean average surface roughness and root mean square roughness values of demineralized enamel treated with ICON were significantly higher than untreated lesions (P < 0.001). The mean Vickers hardness values for demineralized enamel treated with ICON was significantly higher than untreated lesions (P < 0.001). SEM showed irregular, pitted and rough demineralized enamel surface with destruction of enamel rods and dissolution of enamel crystals. After ICON application, the surface showed complete blockage of enamel rods with RI and irregular, rough uneven topography. ConclusionRI application on proximal incipient caries increased surface roughness and hardness significantly.

Three-dimensional facial volume analysis using algorithm-based personalized aesthetic templates

Three-dimensional stereophotogrammetry is commonly used to assess volumetric changes after facial procedures. A lack of clear landmarks in aesthetic regions complicates the reproduction of selected areas in sequential images. A three-dimensional volumetric analysis was developed based on a personalized aesthetic template. The accuracy and reproducibility of this method were assessed. Six female volunteers were photographed using the 3dMDtrio system according to a clinical protocol, twice at baseline (T1) and twice after 1year (T2). A styrofoam head was used as control. A standardized aesthetic template was morphed over the baseline images of the volunteers using a coherent point drift algorithm. The resulting personalized template was projected over all sequential images to assess surface area differences, volume differences, and root mean square errors. In 12 well-defined aesthetic areas, mean average surface area and volume differences between the two T1 images ranged from −7.6mm2 to 10.1mm2 and −0.11cm3 to 0.13cm3, respectively. T1 root mean square errors ranged between 0.24mm and 0.62mm (standard deviation 0.18–0.73mm). Comparable differences were found between the T2 images. An increase in volume between T1 and T2 was only observed for volunteers who gained in body weight. Personalized aesthetic templates are an accurate and reproducible method to assess changes in aesthetic areas.

Estimating Vehicle Fuel Economy from Overhead Camera Imagery and Application for Traffic Control

Industrial machine vision applications frequently employ Photometric Stereo (PS) methods to detect fine surface defects on objects with challenging surface properties. To achieve highly precise results, acquisition setups with a vast amount of strobed illumination angles are required. The time-consuming nature of such an undertaking renders it inapt for most industrial applications. We overcome these limitations by carefully tailoring the required light setup to specific applications. Our novel approach facilitates the design of optimized acquisition setups for inline PS inspection systems. The optimal positions of light sources are derived from only a few representative material samples without the need for extensive amounts of training data. We formulate an energy function that constructs the illumination setup which generates the highest PS accuracy. The setup can be tailored for fast acquisition speed or cost efficiency. A thorough evaluation of the performance of our approach will be given on a public data set, evaluated by the mean angular error (MAE) for surface normals and root mean square (RMS) error for albedos. Our results show, that the obtained optimized PS setups can deliver a reconstruction performance close to the ground truth, while requiring only a few acquisitions.

3D printing of CF/nylon composite mold for CF/epoxy parabolic antenna

Parabolic antennas, which are wildly used as high-gain antennas for point-to-point communications, need many iterations of design-fabrication-test in parabolic antenna development. However, traditional molding via mechanical processing takes a long manufacturing cycle and high cost. In this paper, a 3D-printed CF/nylon composite parabolic mold for CF/epoxy parabolic antenna is studied. It’s found that the coefficient of thermal expansion (CTE) of 3D-printed CF/nylon composite is usually anisotropic due to the low adhesion between printed layers and the aligned short carbon fiber along the printing trace. Here an inclined mode of 3D printing could uniform the CTE of the antenna mold and solve the problems of large printing steps and the separation of supports and mold occurred in horizontal and vertical modes, respectively. The parabolic mold also reveals high profile precision with a low root mean square (RMS) deviation of 0.14 mm. Utilizing the 3D-printed CF/nylon composite mold, parabolic antenna skin with low surface RMS deviation of 0.16 mm was successfully fabricated by laying CF/epoxy prepreg and curing in autoclave. This research about isotropic and smooth 3D-printed CF/nylon mold may support the low-cost and rapid mold development for microwaves relay links on ground and satellite communication antennas.

Structural and optical properties of hematite and L-arginine/hematite nanostructures prepared by thermal spray pyrolysis

A study of structural and optical properties of hematite and L-arginine/hematite films was carried out. Hematite films were deposited by thermal spray pyrolysis on fluorine-doped tin oxide at temperatures varying from 280 to 430 °C. X-ray diffraction results revealed (104) and (110) planes, describing the rhombohedral structure of hematite. Scanning electron microscopy on hematite films showed nanoparticles of grain sizes ranging between 40.0 ± 0.5 and 100.0 ± 0.5 nm. Hematite nanoparticles were transformed to nanospheres with uniform size of 35.0 ± 0.5 nm, using chemical bath deposition and L-arginine, a biomolecule as a structure-directing agent. Raman peaks revealed two A1g and five Eg phonon vibrational modes of hematite. Atomic force microscopy confirmed an increase in the surface root mean square roughness from 35 to 40 nm for hematite nanoparticles and L-arginine/hematite, respectively, which is desirable for charge transport. The films exhibited an indirect band gap varying from 2.08 to 2.30 eV and an onset absorbance that ranged between 525 and 560 nm. An improved current density was observed on l-arginine/hematite from pristine hematite nanostructures.

Comparative Study of ZnO Thin Films Grown on Quartz Glass and Sapphire (001) Substrates by Means of Magnetron Sputtering and High-Temperature Annealing

In this work, we reported a comparative study of ZnO thin films grown on quartz glass and sapphire (001) substrates through magnetron sputtering and high-temperature annealing. Firstly, the ZnO thin films were deposited on the quartz glass and sapphire (001) substrates in the same conditions by magnetron sputtering. Afterwards, the sputtered ZnO thin films underwent an annealing process at 600 °C for 1 h in an air atmosphere to improve the quality of the films. X-ray diffraction, scanning electron microscopy, atomic force microscopy, X-ray photoelectron spectroscopy (XPS), ultraviolet-visible spectra, photoluminescence spectra, and Raman spectra were used to investigate the structural, morphological, electrical, and optical properties of the both as-received ZnO thin films. The ZnO thin films grown on the quartz glass substrates possess a full width of half maximum value of 0.271° for the (002) plane, a surface root mean square value of 0.50 nm and O vacancies/defects of 4.40% in the total XPS O 1s peak. The comparative investigation reveals that the whole properties of the ZnO thin films grown on the quartz glass substrates are comparable to those grown on the sapphire (001) substrates. Consequently, ZnO thin films with high quality grown on the quartz glass substrates can be achieved by means of magnetron sputtering and high-temperature annealing at 600 °C.

Three-dimensional characterization method of pile–rock interface roughness based on fractal geometry

Shaft friction is an important component of the pile foundation bearing capacity in construction projects, whereas the roughness of a pile–rock interface is one of the key components affecting shaft friction. An accurate characterization of the roughness of a pile–rock interface can help in determining the lateral friction of the pile–rock interface. In the present study, a new fractal geometry characterization parameter was proposed based on traditional roughness characterization methods and the structural function of a fractional Brownian field, namely, the three-dimensional (3D) characteristic roughness parameter l∗. Its definition, geometric meaning, and calculation method are described herein. In addition, photogrammetry was used to obtain grayscale images of pile–rock interfaces from an actual construction project. The results verified through a 3D reconstruction method reveal that the grayscale values can be used to represent the changes in the interface profile. Consequently, the 3D fractal dimension D, the surface root mean square deviation Sq, and the 3D characteristic roughness l∗ were calculated based on the grayscale values of the processed images. A comparison and verification of the results demonstrate that the 3D characteristic roughness parameter is more objective and advantageous than the other parameters. The 3D characteristic roughness is not only suitable for characterizing the roughness of pile–rock interfaces, but also applicable to characterize the roughness of other surface types, including rock discontinuities, rock joints, and concrete and road surfaces.

Surface statistical properties of solid state reacted CZTSe compounds prepared in five different ratios

Copper Zinc Tin Selenide (CZTSe) has attracted much attention in recent times, for an absorber layer in thin film solar cells, due to high natural abundance of its constituents and their non-toxicity. In this work preparation of CZTSe compounds through solid state reaction of elemental precursors, namely Cu, Zn, Sn and Se and study of surface roughness, using the atomic force microscopy (AFM) has been presented. In order to study the influence of compositional variation on surface morphology, quantitative roughness and surface characteristics have been evaluated from AFM characterization. Surface roughness and grain size along with parameters like surface kurtosis, skewness and root mean square (RMS) roughness have been discussed. A significant difference has been observed in roughness parameters and grain size with respect to Cu/Zn variations. It has been concluded that deficiency of Cu and excess of Zn, caused decrement in mean grain size of the material with respect to perfect stoichiometric sample. These observations have also been verified using SEM-EDAX and FTIR studies.

Analysis of crystallization phenomenon in Indian honey using molecular dynamics simulations and artificial neural network

Molecular dynamics simulation was performed on sugar profile and moisture content-based mixture systems of six Indian honey samples. Comparative studies were performed to understand the interactive effects of fructose, glucose, sucrose, maltose and water on crystallization. All simulations led to formation of stable crystal but with different interaction energies. Post-simulation analysis showed that Fructose:Glucose of 1.18 formed the most stable crystal with highest van der Waals and electrostatic interactions. The stability of crystal was further validated with least gyration radius (209 ± 1.81 nm2), accessible surface area (4.09 ± 0.04 nm) and root mean square displacement (3.51 ± 0.00261 nm). Results indicated that not only Fructose:Glucose ratio but also sucrose, maltose and water had a significant effect on the overall crystallization process. The simulation data was used to train the artificial neural network which predicted the stability of honey crystallization depending on Fructose:Glucose and Glucose:Water ratios.

Thickness dependence of microstructure and properties in Be2C coatings as a promising ablation material

Beryllium carbide (Be2C) thin films have proven to be promising ablation materials, but the properties of Be2C coatings of the greater thickness required for inertial confinement fusion capsules are still unknown. In this work, Be2C coatings of various thicknesses (0.3–32.9 µm) are prepared by DC reactive magnetron sputtering. The influence of thickness on crystal properties, microstructure, and optical properties is investigated. The results indicate that the crystallinity of polycrystalline Be2C films improves with increasing thickness, while the grain size (∼5 nm) and texture properties (without a preferred orientation) have only a weak dependence on thickness. A uniform featureless microstructure and smooth surface (root mean square roughness ∼8 nm) are observed even in thick (32.9 µm) films, despite the presence of defects induced by contaminants. High densities (2.19–2.31 g/cm3) and high deposition rates (∼270 nm/h) are realized, with the latter corresponding to the upper limit for the fabrication of Be2C coatings by magnetron sputtering. The transmittance of the films in the near-infrared region remains at a high level (&amp;gt;80%) and has only a weak dependence on thickness, while the transmittance in the visible region decreases with increasing thickness. In addition, the optical bandgap is estimated to be about 1.9 eV and decreases with increasing thickness owing to the presence of defects.

Effect of Indium Doping on the Structural and Optical Properties of CdO thin films

The aim of this study is to investigate the effect of indium doping on structural and optical characteristics of CdO thin films prepared by spray pyrolysis. According to x-ray diffraction analysis, the studied samples are polycrystalline with preferred orientation along (111) orientation. The surface topography determined by AFM and SEM indicates that the surface roughness and root mean square (RMS) values were increased as the indium doping concentration increased. The determinedoptical energy gap were found to lie between (2.47-2.84)eV.

Microstructure, roughness, and stress properties of silicon coatings for shape correction of Kirkpatrick–Baez mirrors

Coating techniques are investigated for accurate shape correction of Kirkpatrick–Baez (KB) mirrors. Au and Pt have been used as coating materials to obtain elliptical KB mirrors from flat or cylindrical Si substrates. However, due to large differences in the thermal expansion coefficients between Au (or Pt) and Si, thermal stress can be induced not only when coating the substrate, but also during use when focusing synchrotron beams. Si is a promising alternative for profile coating because not only the same material as substrate can induce much smaller thermal stress, but also Si is generally smooth. The microstructure and roughness of 1000- and 2000-nm-thick Si coatings deposited at two different pressures (0.133 and 0.266 Pa) are explored. When the thickness increases from 50 to 2000 nm, the film microstructure and surface morphology change and root mean square roughness increases from 0.164 to 0.232 nm. The increase in Si coating thickness contributes the most to power spectral density curves when the frequency is between 1 and 20 μm − 1. No obvious changes resulting from intrinsic stress are observed among the samples when the Si coating thickness is increased from 50 to 2000 nm.

Mid-infrared emissions from In(Ga)As quantum wells grown on GaP/Si(001) substrates

This work reports on the approach of metamorphic In(Ga)As quantum wells on GaP/Si(001) substrates for Si-based mid-infrared applications. Metamorphic InP and In0.83Al0.17As templates are grown on Si, and room temperature photoluminescence emissions at 2.1 μm and 2.6 μm have been demonstrated from InAs/In0.53Ga0.47As triangular quantum wells and InAs quantum wells on the templates, respectively. The surface root mean square roughness is 4-5 nm. The quantum wells act fully strained and the threading dislocation density is 107-108 cm-2 in the upper side of buffer.

Simulation of the effects of non-Newtonian fluid on the behavior of a step hydraulic rod seal based on a power law fluid model

The rheological characteristics of the oil film on the rod-seal interface in the sealing zone have a major influence on the behavior of reciprocating seals. Because of the addition of polymers, the viscosity and temperature properties of hydraulic oil have improved and the fluid presents non-Newtonian characteristics. To investigate the influence of these characteristics on seal behavior, a soft elastohydrodynamic lubrication (EHL) numerical model is introduced to simulate a step seal under a mixed lubrication condition. A modified Reynolds equation is derived for calculating the fluid film pressure distribution more accurately. The equation is based on the power law fluid model and Jakobsson-Floberg-Olsson (JFO) cavitation theory. Results are presented to gain insight into the effect of non-Newtonian fluid characteristics on seal behavior, and the simulated results are compared to those of a Newtonian fluid to reveal the seal mechanism. The influence of operating parameters and the seal surface root mean square (RMS) roughness on sealing performance under different power law indexes is also investigated and discussed.

CCTO thin film synthesis by radio frequency magnetron sputtering

In the present work CCTO thin film has successfully deposited on FTO substrate in a non-reactive (argon) atmosphere with frequency (RF) magnetron sputtering at 300 W. This work aims to determine the structural, morphological and optical properties of thin film using X-ray diffraction (XRD), atomic force microscopy (AFM) and Ultraviolet–visible spectroscopy (UV-Vis), respectively. The result shows that the nature of CCTO thin film is polycrystalline with cubic structure. XRD peaks confirmed the presence of CCTO phase with the crystal planes of (022), (013), (033), (024), and (224). The average crystallite size was 32 nm as measured by Willamson-Hall method. The surface roughness (Ra) and root mean square (RMS) of CCTO thin film were 26 nm and 33 nm, respectively. The maximum optical transmittance of CCTO thin film was more than 80% in the visible region (550-1000 nm) while calculated optical energy bandgaps was 3.2 eV.

The Synergistic Roles of Temperature and Pressure in Thermo-Compression Bonding of Au

Au-Au thermocompression bonding is a widely used technique for a variety of applications including hermetic sealing and packaging at a fine pitch. We have investigated the roles of pressure and temperature individually at different pressures (15 -100 MPa) and temperatures (150 and 250° C) of sputter deposited 1.2 μm thick Au thin films using a flattening technique. The initial surface root mean square (RMS) roughness of deposited films was 3-5 nm. Void morphology and the evolution of the interface was studied using atomic force microscopy. Power spectral density function plots were used to study variation in asperities at the surface. The void morphology and evolution was different when flattening and bonding at different temperatures and pressures.

CHARACTERIZATION OF OCTADECYLTRICHLOROSILANE SELF-ASSEMBLED MULTILAYERS ON PYREX GLASS

In this paper, octadecyltrichlorosilane (OTS) self-assembled multilayer (SAM) films are fabricated on Pyrex glass by dipping method. The hydrophobicity, constituent and surface morphology of OTS SAM at various dipping times in solutions of 1, 2 and 5[Formula: see text]mM concentrations are investigated. Characteristic absorption peaks around 2850 and 2920[Formula: see text]cm[Formula: see text] are observed by FTIR and island-like structures on samples are detected by AFM. After 15[Formula: see text]min dipping time for solution of 5[Formula: see text]mM, water contact angle of the sample reaches the maximum value of 116.4[Formula: see text] with relatively low surface root mean square (Rms) roughness of 0.152[Formula: see text]nm. The critical surface tension ([Formula: see text] of the analyzed sample is 18.2[Formula: see text]dyne/cm. The optimum dipping time in the solution of 5[Formula: see text]mM for a complete SAM film is about 30[Formula: see text]min. The study of the optimal conditions for the formation of integrated OTS SAM has significant scientific and practical values in modification of solid surfaces.

Solution-processed phosphorus-tungsten oxide film as hole injection layer for application in efficient organic light-emitting diode

The research on new functional layer materials and optimization of fabrication in organic light-emitting diode (OLED) has been continuously concerned. In this work, phosphotungstic acid solution used as a precursor is spin-coated onto ITO anode, and then a phosphorus-tungsten oxide (WO3-P2O5) film is obtained after annealing treatment. Various parameters which include film composition, surface morphology, work function and optical property are measured. It suggests that the film has the composition of 24 WO3·P2O5 annealed at 200 °C, which exhibits work function of 5.55 eV, surface root mean square (RMS) roughness value of 1.525 nm and optical transmittance of over 92%. The WO3-P2O5 film is used as hole injection layer (HIL), and the OLED with the structure of [ITO/ WO3-P2O5/ TPD/ Alq3/ LiF/ Al] is fabricated. The performance of device shows turn-on voltage of 2.6 V, maximum luminance of 13553 cd/m2, maximum current efficiency of 5.87 cd/A and maximum power efficiency of 3.44 lm/W, respectively. The results provide a new way to deposit HIL based on solution-processed metal oxide in efficient OLED.

Measuring and analyzing thermal deformations of the primary reflector of the Tianma radio telescope

The primary reflector of the Tianma Radio Telescope (TMRT) distorts due to the varying thermal conditions, which dramatically reduces the aperture efficiency of Q-band observations. To evaluate and overcome the thermal effects, a thermal deformations measurement system has been established based on the extended Out-of-Focus holography (e-OOF). The thermal deformations can be measured in approximately 20 min with an illumination-weighted surface root mean square (RMS) accuracy of approximately 50 μm. We have measured the thermal deformations when the backup and front structure were heated by the sun respectively, and used the active surface system to correct the thermal deformations immediately to confirm the measurements. The thermal deformations when the backup structure is heated are larger than those when the front structure is heated. The values of half power beam width (HPBW) are related to the illumination-weighted surface RMS, and can be used to check the thermal deformations. When the backup structure is heated, the aperture efficiencies can remain above 90% of the maximum efficiency at 40 GHz for approximately two hours after one adjustment. While the front structure is heated, the aperture efficiencies can remain above 90% of the maximum efficiency at 40 GHz, and above 95% after one adjustment in approximately three hours.