Generalized ellipsometry of artificially designed line width roughness

We use azimuthally resolved spectroscopic Mueller matrix ellipsometry to study a periodic silicon line structure with and without artificially-generated line width roughness (LWR). We model the artificially perturbed grating using one- and two-dimensional rigorous coupled-wave methods in order to evaluate the sensitivity of the experimental spectrally resolved data, measured using a generalized ellipsometer, to the dimensional parameters of LWR. The sensitivity is investigated in the context of multiple conical mounting (azimuth angle) configurations, providing more information about the grating profile.     

Comparison of line edge roughness and profile angles of chemical vapor deposited amorphous carbon etched in O2/N2/Ar and H2/N2/Ar inductively coupled plasmas

In this study, we compared the line edge roughnesses (LER) and profile angles of chemical vapor deposited (CVD) amorphous carbon (a-C) patterns etched in an inductively coupled plasma (ICP) etcher produced by varying process parameters such as the N₂ gas flow ratio, Q (N₂), and dc self-bias voltage (V_dc) in O₂/N₂/Ar and H₂/N₂/Ar plasmas. The tendencies of the LER and profile angle values of the etched CVD a-C pattern were similar in both plasmas. The LER was smaller in the O₂/N₂/Ar than in the H₂/N₂/Ar plasmas, and the profile angle was larger in the O₂/N₂/Ar than in the H₂/N₂/Ar plasmas under the same processes conditions. The use of O₂/N₂/Ar plasma was more advantageous than the H₂/N₂/Ar plasma for controlling LER and profile angle.     

Effect of surface roughness on measurement of light distribution in intralipid suspension

Light distribution in the biological tissue phantom intralipid suspension with different interface roughness was measured for quantitative understanding of surface roughness effect. The results show that the surface roughness strongly affects light distribution inside the approximately semi-infinite biological tissue phantom. The phantom surface possesses a certain degree roughness and the effect of the surface roughness on measurement results of light distribution in tissue is substantial, so the measurement of light distribution in biological tissue needs to take surface roughness into account.     

Empirical model of roughness effect on vehicle speed

Vehicle speed–roughness relationship has a significant research gap in life cycle assessment model. The current available models describing the roughness effect on vehicle speed are very limited and outdated. In this paper, 32 individual pavement sections, each of which has roughness data of up to 8 years, were selected to develop the model. The roughness data cover a wide range, and the selected pavement sections contain both flexible and rigid pavement types and various numbers of lanes. Involved regression variables include the following: vehicle speed, roughness, volume–capacity ratio, pavement type, number of lanes and speed limit. Analysis of variance was first performed, indicating that pavement type and speed limit are not significant factors influencing the average vehicle speed. Following, strict statistical technique was used to correct the unobserved heterogeneity during the regression using a one-way fixed random model. The obtained regression model reveals that the average vehicle speed decreases 0.0083 mph with every 1 in/mi increase of the roughness ( ? 0.84 km/h per m/km).     

Characterization of tensile properties and microstructures in directionally solidified Al–Si alloys using linear roughness index

The tensile properties in directionally solidified Al–Si alloys and in gravity die casting of the same composition are presented. Examples of relating both the tensile and the microstructural properties of these alloys with the fracture roughness index are indicated. The roughness index was measured on vertical sections cut through the tensile fracture surface. The tensile properties examined were the yield and ultimate tensile strengths, strain at fracture, and Young's modulus. The analyzed microstructural features were porosity, dendrite area fraction, secondary dendrite arm spacing, and Si particle spacing. In almost all cases an unambiguous correlation was found between the roughness index and the tensile or the microstructural properties. A marked improvement in ductility was observed for directionally solidified samples over their gravity die casting processed counterparts. The roughness index diminished going from die cast to direction solidification, and this is likely accompanied by change in the fracture mechanisms.     

Study the parametric effect of abrasive water jet machining on surface roughness of Inconel 718 using RSM-BBD techniques

This paper presents an experimental investigation to ascertain the parametric impact of abrasive water jet machining on the surface quality of Inconel 718 material. Experiments were designed according to response surface methodology-box Behnken design by maintaining three levels of four process parameters—abrasive flow rate, water pressure, stand-off distance and traverse speed. The surface irregularity is measured during machining. The design expert software was used to establish an optimized mathematical model of process parameters for achieving the required surface roughness. Desirability function has also been used to optimize the process parameters. The confirmation experiments validate the reliability and capability of the developed model. Further, the surface characteristics were analyzed through scanning electron microscope images and energy-dispersive X-ray spectroscopy.     

Investigation of granular surface roughness effect on electrostatic charge generation

Electrostatic charge generation is a multivariable and complex issue whose working mechanism has never been fully understood. The objective of this paper is to investigate the effect of granule surface roughness on electrostatic charge generation. Two kinds of granule material, Polyvinyl chloride (PVC) and polypropylene (PP) were used with the granule size of 4 mm diameter, 2 mm height and the shape was cylinder or semi-cylinder. The working surfaces were grounded and roughness ranged from 0.140 to 8.600 μm. It was found that uneven surfaces tended to give rise to voids between two solids, where air stored in the voids was able to accelerate discharging. With the same roughness, PVC tended to generate more electrostatic charge than PP by one order of magnitude. For both materials, electrostatic charge generation first increased with surface roughness and then decreased. The maximum electrostatic charge generated was found to occur when the effects of interaction, contact area and voids discharging were at equilibrium. With the combined effect of humidity, surface roughness and contact area, highest electrostatics generation occurred near the mid-roughness tested in this work. Humidity had more effect on electrostatic charge generation as the granule working surface had lower roughness.     

The effect of fibre surface roughness on the mechanical behaviour of ceramic matrix composites

The interface between the matrix and the fibre plays an important role in controlling the strength and toughness of ceramic matrix composites. It has been found experimentally that depending on manufacturing process, the interface may show substantial surface roughness, which has been modelled analytically with certain degree of success. The analytical models, however, do not take into account the interface geometry. Instead, only the magnitude of the surface undulation is included. In this paper, a direct simulation of fibre–matrix interface roughness by the finite element method is performed on an axisymmetric unit cell with a fully debonded interface. The simulation is employed to account for the three dimensional stress state, surface roughness and interface friction, which are normally simplified or idealised in theoretical studies. The model gives the highly non-uniform interface shear and pressure, which have direct implications on the interface damage and composite behaviour. Under the approximation made in the model, the positive transverse strains does not show up in the simulation despite the fact that two different surface roughness are used.     

Atomic-scale cellular model and profile simulation of Si etching: Formation of surface roughness and residue

Formation mechanisms for profile anomalies such as surface roughness and residue have been investigated numerically and experimentally for Si etching in Cl₂/O₂ plasmas. The numerical simulation employed an atomic-scale cellular model (ASCeM) based on the Monte Carlo algorithm, which reproduced the feature profile evolution experimentally observed during etching at increased O₂ concentrations. A comparison between simulation and experiment indicated that the local surface oxidation induces surface roughness at the bottom of the feature during etching; then, synergistic effects between surface oxidation and ion scattering in microstructural features on roughened surfaces increase the surface roughness, which in turn causes a number of significant residues or micropillars on bottom surfaces of the feature. In practice, in roughened microstructural features, geometrical shadowing effects for neutral oxygen suppress the surface oxidation at the local feature bottom, where the energetic ion incidence is increased owing to ion scattering on sidewalls of the local feature.     

Modelling the combined effect of surface roughness and topography on bacterial attachment

Bacterial attachment is a complex process affected by flow conditions,imparted stresses,and the sur-face properties and structure of both the supporting material and the cell.Experiments on the initial attachment of cells of the bacterium Streptococcus gordonii (S.gordonii),an important early coloniser of dental plaque,to samples of stainless steel (SS) have been reported in this work.The primary aim motivating this study was to establish what affect,if any,the surface roughness and topology of sam-ples of SS would have on the initial attachment of cells of the bacterium S.gordonii.This material and bacterium were chosen by virtue of their relevance to dental implants and dental implant infections.Prior to bacterial attachment,surfaces become conditioned by the interfacing environment (salivary pellicle from the oral cavity for instance).For this reason,cell attachment to samples of SS pre-coated with saliva was also studied.By implementing the Extended Derjaguin Landau Verwey and Overbeek(XDLVO) theory coupled with convection-diffusion-reaction equations and the surface roughness infor-mation,a computational model was developed to help better understand the physics of cell adhesion.Surface roughness was modelled by reconstructing the surface topography using statistical parame-ters derived from atomic force microscopy (AFM) measurements.Using this computational model,the effects of roughness and surface patterns on bacterial attachment were examined quantitatively in both static and flowing fluid environments.The results have shown that rougher surfaces (within the sub-microscale) generally increase bacterial attachment in static fluid conditions which quantitatively agrees with experimental measurements.Under flow conditions,computational fluid dynamics (CFD) simula-tions predicted reduced convection-diffusion inside the channel which would act to decrease bacterial attachment.When combined with surface roughness effects,the computational model also predicted that the surface topographies discussed within this work produced a slight decrease in overall bacterial attachment.This would suggest that the attachment-preventing effects of surface patterns dominate over the adhesion-favourable sub-microscale surface roughness;hence,producing a net reduction in adhered cells.This qualitatively agreed with experimental observations reported here and quantitatively matched experimental observations for low flow rates within measurement error.     

Investigation of Mo/Si and W/Si interfaces by phase modulated spectroscopic ellipsometry and cross-sectional transmission electron microscopy

Mo and W thin films and Mo/Si/Mo and W/Si/W tri-layers have been deposited by r.f. magnetron sputtering on c-Si substrates as a precursor to the fabrication of Mo/Si and W/Si multilayer X-ray mirrors. The Phase Modulated Spectroscopic Ellipsometry (SE) technique has been used for characterizing the single layer films to derive information regarding the thickness and volume fraction of voids present in the surface layers. The Mo/Si/Mo and W/Si/W tri-layer structures have been characterized by the Cross-sectional Transmission Electron Microscopy (XTEM) technique. The inter-diffusion at the interfaces of the tri-layer structures observed by the XTEM technique has been correlated to the thickness of the surface layers of the metal films obtained from the SE measurement.     

Influence of surface roughness created by admixing smaller particles on improving discharge particle flowability of main particles

Particle flowability can be improved by admixing with particles smaller than the main particles. However, the mechanism by which this technique improves flowability is not yet fully understood. In this study, we focused on vibrating discharge particle flowability as one type of flowability and investigated the influence of the main particle roughness created by the adhesion of the admixed particles on improving the flowability. The diameters of the main and admixed particles (MPs and APs) were 41.4 or 60.8?μm and 8 or 104?nm, respectively. The main and admixed particles were mixed in various mass ratios, and the discharge particle flow rates of the mixed particles were measured. Scanning electron microscopy images were acquired from two different angles to determine the three-dimensional surface roughness using image analysis software. We then calculated the coating structure parameters from the obtained three-dimensional surface roughness. The observed trends for improving the vibrating discharge particle flowability were found to differ from those reported for compression particle flowability. Furthermore, the main particle roughness conditions that led to the greatest improvement involved the presence of several admixed particle agglomerations between the main particles.     

一种基于图像处理的输电线路覆冰监测方法

在电力系统中,输电线路的覆冰现象非常普遍.严重的覆冰情况会造成巨大的经济损失和不良的社会影响.针对现有输电线路覆冰厚度的检测方法的不足,提出了一种基于图像处理的输电线路覆冰的监测方法,并详细介绍了其实现方式.该系统通过摄像机采集覆冰图像,进而对图像进行边界检测处理,测量出覆冰厚度;覆冰图像及覆冰厚度通过GPRS无线传输方式发送到监控中心,由监控人员做出相应的处理.实验表明,该监测系统能够实现输电线路覆冰的在线监测,且性能稳定,精度较高,具有广阔的应用前景.     

Interface roughness effect between gate oxide and metal gate on dielectric property

We report a simple theoretical model based on experimental data about the interface roughness effect between gate oxide and metal gate on dielectric. From the analytic approach, we confirm that the increase in interface roughness generates the decrease in the dielectric constant as well as the increase in the leakage current. We checked the interface roughness effect between high-κ HfO₂ gate oxides and Ru gates by atomic layer deposition (ALD) and physical vapor deposition (PVD). The ALD Ru gate showed better dielectric properties (high dielectric constant and low leakage current) and lower interface roughness than the PVD Ru metal gate.     

基于原子力显微镜技术的沥青与矿料表面粗糙度及黏附特性

采用原子力显微镜技术(AFM)的轻敲和力曲线模式,在微观尺度下对沥青与矿料表面的二维图像和三维形貌信息进行采集和分析,并测试和计算表征材料物理黏结特性的表面能。测试和分析结果显示,不同油源的沥青具有明显不同的化学组分和表面粗糙度,具有蜂形结构的沥青表面粗糙度更大。老化将明显减少沥青的表面粗糙度,降低其表面能,进而对沥青与矿料的黏附产生不利影响。结合宏观的黏附拉拔力学试验,对沥青和矿料表面粗糙度、表面能与宏观拉拔强度间的关联进行统计分析。结果表明,对于含蜂形结构的沥青,沥青和矿料表面粗糙度对黏附力学性能较为重要;而对于不含蜂形结构的沥青,其与矿料的黏附性更决定于所选材料的表面能,即两种材料间的物理黏结作用。     

基于高阻硅衬底的微波传输线和数字移相器

在高阻硅衬底上微波传输线以及工作在7.5～8.5GHz频带的四位数字移相器.测试表明,在高阻硅衬底上制备的50Ω微带线在5～15GHz频率范围内的插入损耗低于0.8dB/cm;在同样衬底上用混合集成技术制作的7.5～8.5GHz四位数字移相器的各状态插入损耗为(7.5±3)dB,回波损耗大于12dB,均方根(RMS)相位误差小于5°.具有良好的微波器件性能.     

基于AFM的刻线边缘粗糙度幅值与空间频率的表征方法

针对使用原子力显微镜测量纳米尺度半导体刻线边缘粗糙度的参数表征问题进行了研究．在对线边缘粗糙度的定义与现有测量方法进行分析的基础上,采用图像处理技术分析硅刻线的原子力显微镜测量图像的线边缘粗糙度特征,提出了线边缘粗糙度的幅值与空间频率的表征方法．其中幅值参数能够在一定意义上反映刻线边缘形貌的均匀性,而采用小波多分辨分析与功率谱密度函数（PSD）频谱分析相结合的空间频率表征方法,则有效地分析了侧墙轮廓边缘复杂的空间信息．实际测量结果表明,样本线边缘粗糙度的主要能量集中在低频区域,其主导空间频率为～0．04nm^-1,在低频部分约500nm特征波长上有最大的线边缘粗糙度分布．     

The adaptive slicing algorithm and its impact on the mechanical property and surface roughness of freeform extrusion parts

In the process of fused deposition modelling, the layer thickness plays a vital role in determining the surface quality and forming time. If a larger layer thickness is adopted, the molding time will be shorter, as a result, the surface accuracy of the product will be worse at the same time. If a smaller thickness is used, the surface quality of the product can be guaranteed, but the molding time will be very long accordingly. Therefore, there exists conflict between guaranteeing the surface quality and shortening the forming time of the part. This paper adopts adaptive slicing algorithm to solve this conflict. According to the curvature of the model, an appropriate thickness value is adopted automatically where the model curvature is large, a smaller thickness value is necessary, on the contrary, a larger thickness value is used. The tensile strength experiment was made through the specimens of ASTM D638 to study the influence of layer thickness. The temperature of the first six layers in the processing of building was collected. The ultra-depth picture of the cross-sectional area showed that the temperature would affect the neck length between adjacent filaments. Moreover, the surface roughness of the cylinder with different layer thicknesses was measured and the Ra curve figures showed the surface roughness was also influenced by layer thickness. The experiment results suggested the layer thickness was a critical factor in determining mechanical property and surface roughness by changing the layer counts and the neck length between adjacent filaments. It can be noted from the experiments that the adaptive slicing algorithm was not only good at enhancing the surface accuracy and tensile strength, it could also improve the building efficiency.     

Characterization and modeling of transition edge sensors for high resolution X-ray calorimeter arrays

Characterizing and understanding, in detail, the behavior of a Transition Edge Sensor (TES) is required for achieving an energy resolution of 2 eV at 6 keV desired for future X-ray observatory missions. This paper will report on a suite of measurements (e.g. impedance and I–V among others) and simulations that were developed to extract a comprehensive set of TES parameters such as heat capacity, thermal conductivity, and R(T,I), (T,I), and β_i(T,I) surfaces. These parameters allow for the study of the TES calorimeter behavior at and beyond the small signal regime.     

Influence of steel roughness on internal and external corrosion of tinplate cans

Reductions in tin coatings and thickness of tinplate affect the properties of the tinplate surfaces. Computer-aided electrochemical test methods, impedance spectroscopy and X-ray microanalytical studies show that corrosion behaviour is influenced by the base material properties. This paper will give some information about surface properties of tinplate and aspects of internal and external corrosion resistance. Special attention is given to the formation of micropores in lacquered tinplate during stamping and beading.