Surface Topography Properties Research Articles

Detecting surface change on Venus from Magellan and VERITAS radar images

Detection of surface changes due to recent volcanism on Venus is a major focus of upcoming orbiting radar missions like VERITAS (Venus Emissivity, Radio science, InSAR, Topography, And Spectroscopy). The longest time baseline is to the Magellan mission, but these images will differ in wavelength (3.8 cm for VERITAS and 12.6 cm for Magellan), and often in incidence angle coverage. We explore the range of backscatter differences due to self-affine scaling properties of surface topography, using a model derived from terrestrial measurements. For moderately rough surfaces at least a 3-dB difference in backscatter coefficient above (rougher new flows) or below (smoother new flows) a model-scaled Magellan echo is required for confident change detection given uncertainty in the Hurst exponent of the topography. As roughness increases, echo saturation occurs due to diffuse scattering, and detectable change is due only to smoothing of the surface between the two missions. Quasi-specular echoes make change detection more challenging when the Magellan incidence angle is <30o (corresponding to latitudes below 35oS or above 55oN). At higher latitude, stronger correlative evidence from geologic context and more attention to local slope is required to infer surface change. There will be significant differences in the extent of mapped surficial mantling units between the two wavelengths. Further radar image data linked with terrestrial field measurements at the few-cm scale can validate the empirical model that relates surface roughness to wavelength dependence in radar scattering.

Properties and Characterization Techniques of Graphene Modified Asphalt Binders.

Graphene is a carbon-based nanomaterial used in various industries to improve the performance of hundreds of materials. For instance, graphene-like materials have been employed as asphalt binder modifying agents in pavement engineering. In the literature, it has been reported that (in comparison to an unmodified binder) the Graphene Modified Asphalt Binders (GMABs) exhibit an enhanced performance grade, a lower thermal susceptibility, a higher fatigue life, and a decreased accumulation of permanent deformations. Nonetheless, although GMABs stand out significantly from traditional alternatives, there is still no consensus on their behavior regarding chemical, rheological, microstructural, morphological, thermogravimetric, and surface topography properties. Therefore, this research conducted a literature review on the properties and advanced characterization techniques of GMABs. Thus, the laboratory protocols covered by this manuscript are atomic force microscopy, differential scanning calorimetry, dynamic shear rheometer, elemental analysis, Fourier transform infrared spectroscopy, Raman spectroscopy, scanning electron microscopy, thermogravimetric analysis, X-ray diffraction, and X-ray photoelectron spectroscopy. Consequently, the main contribution of this investigation to the state-of-the-art is the identification of the prominent trends and gaps in the current state of knowledge.

Effects of a New Type of Grinding Wheel with Multi-Granular Abrasive Grains on Surface Topography Properties after Grinding of Inconel 625.

Finishing operations are one of the most challenging tasks during a manufacturing process, and are responsible for achieving dimensional accuracy of the manufactured parts and the desired surface topography properties. One of the most advanced finishing technologies is grinding. However, typical grinding processes have limitations in the acquired surface topography properties, especially in finishing difficult to cut materials such as Inconel 625. To overcome this limitation, a new type of grinding wheel is proposed. The tool is made up of grains of different sizes, which results in less damage to the work surface and an enhancement in the manufacturing process. In this article, the results of an experimental study of the surface grinding process of Inconel 625 with single-granular and multi-granular wheels are presented. The influence of various input parameters on the roughness parameter (Sa) and surface topography was investigated. Statistical models of the grinding process were developed based on our research. Studies showed that with an increase in the cutting speed, the surface roughness values of the machined samples decreased (Sa = 0.9 μm for a Vc of 33 m/s for a multigranular wheel). Observation of the grinding process showed an unfavorable effect of a low grinding wheel speed on the machined surface. For both conventional and multigranular wheels, the highest value for the Sa parameter was obtained for Vc = 13 m/s. Regarding the surface topography, the observed surfaces did not show defects over large areas in the cases of both wheels. However, a smaller portion of single traces of active abrasive grains was observed in the case of the multi-granular wheel, indicating that this tool performs better finishing operations.

Modulating Myofibroblastic Differentiation of Fibroblasts through Actin-MRTF Signaling Axis by Micropatterned Surfaces for Suppressed Implant-Induced Fibrosis.

Myofibroblasts, the primary effector cells for implant-induced fibrosis, contribute to this process by secreting excessive collagen-rich matrix and contracting. Thus, approaches that suppress myofibroblasts may achieve desirable suppression effects in the fibrotic process. As one of the important physical properties of materials, material topographical structures have been proven to affect various aspects of cell behaviors, so is it possible to manipulate the formation of myofibroblasts by tailoring the topographical properties of medical devices? In this study, polycaprolactone (PCL) surfaces with typical micropatterns (micro column and micro pit) were fabricated. The regulatory effects of surface micropatterns on the myofibroblastic differentiation of fibroblasts were investigated. Compared to the flat surfaces and surfaces with micro pit, surfaces with micro columns triggered the F- to G-actin transition, inhibiting the nuclear transfer of myocardin-related transcription factor-A. Subsequently, the downstream gene α-smooth muscle actin, which is a marker of myofibroblasts, was suppressed. Further in vivo investigation showed that PCL implants with micro-column-patterned surfaces inhibited the formation of peri-implant fibrotic capsules. Our results demonstrate that surface topographical properties are a potent regulator of fibroblast differentiation into myofibroblasts and highlight the antifibrotic potential of modifying surfaces with micro-column patterns.

Self-assembled cobalt hydroxide micro flowers from nanopetals: Structural, fractal analysis and molecular docking study

A 2D structure of cobalt hydroxide was synthesized by the chemical bath deposition method on the glass substrate. The structure of thin-film was studied using X-ray diffraction (XRD) study. UV–vis. spectroscopy, Fourier transforms infrared spectroscopy (FTIR) and Raman spectroscopies were used for structural conformation. The morphological study of thin film has been characterized by field emission scanning electron microscopy (FESEM) and atomic force microscopy (AFM). Cobalt hydroxide thin film is deposited observed in the form of micro-flowers which are self-created by nanosheets like petals structure. The surface growth of thin film was studied with the help of AFM. Fractal analysis was carried based on AFM data. Fractal dimension and surface topographical properties have been calculated from statistical metric. Theoretically and experimentally observed bandgap is well agreed with each other. The possible formation mechanism of flower‐like cobalt hydroxide is discussed based on experimental results. Further molecular docking analysis of cobalt hydroxide with deoxyribonucleic acid (DNA) was predicated. The study shows that interaction between cobalt hydroxide-DNA is observed via the hydroxyl group.

Tool Wear Rate and Surface Integrity Studies in Wire Electric Discharge Machining of NiTiNOL Shape Memory Alloy Using Diffusion Annealed Coated Electrode Materials

Electrode material used in wire electric discharge machining (WEDM/wire EDM) plays a vital role in determining the machined component quality. In particular, when machining hard materials like nickel titanium/NiTi (NiTiNOL) shape memory alloy, the quality of electrode material is important as it may have adverse effects on the surface properties of the alloy. Different electrode materials give different performances, as each electrode material is made up of different conductivity, compositions and tensile strength. Therefore, detailed experimental studies have been carried out to understand the effect of diffusion annealed coated wires (X-type and A-type) on NiTiNOL SMA during the wire EDM process. The tool wear rate and surface roughness responses have been studied for both the electrode materials against different wire EDM variables such as pulse time, pause time, wire feed and spark gap set voltage. The impact of these process parameters on the stated output responses has been analyzed and further surface and subsurface analysis of the machined component has been carried out to understand the impact of diffusion annealed electrode materials during the wire EDM process. The investigation reveals that an A-type diffusion annealed coated wire is found to be most suitable in terms of tool wear rate, surface roughness and surface integrity during machining of NiTiNOL shape memory alloy compared to X-type and traditional brass-based electrode materials. Surface topographical properties were studied using confocal microscopic analysis and scanning electron microscope (SEM) with energy-dispersive spectroscopy (EDS) analysis. The subsurface analysis like microhardness and recast layer thickness was also studied for both the wires against different machining conditions.

Understanding the effects of annealing temperature on the mechanical properties of layers in FAI-rich perovskite solar cells

This paper uses a combination of experiments and theory to study the effects of annealing temperature on the mechanical properties of hybrid organic–inorganic perovskites (HOIPs). We examined the mechanical (hardness and Young’s modulus), microstructural, and surface topography properties of the HOIP film at different annealing temperatures ranging from 80 to 170 °C. A mechanism-based strain gradient (MSG) theory is used to explain indentation size effects in films at different annealing temperatures. Intrinsic film yield strengths and hardness values (deduced from the MSG theory) are then shown to exhibit a Hall–Petch dependence on the inverse square root of the average grain size. The implications of the results are then discussed for the design of mechanically robust perovskite solar cells.

Physicochemical Research of Clinically Retrieved CU-NI-TI Orthodontic Archwires

Abstract In modern orthodontics, thermally activated archwires are used more widely in clinical practice, because they have unique properties like superelasticity and bio-compatibility. The aim of the present study was to characterize commercial 35° C Cu-NiTi archwires in terms of their phase transition behavior, chemical composition, surface topography properties after clinical usage, as well as the influence of the autoclaving process. Materials and methods. 35° C Thermo-Active Copper NiTi (CuNiTi) of ORMCO, Glendora, CA, USA (as-received, as-received autoclaved and clinically retrieved) with rectangular cross-section and dimension 0.016x0.022 inch, were investigated. The physicochemical research was conducted via Differential Scanning Calorimetry (DSC), Scanning Electron Microscopy (SEM), Energy Dispersive Spectroscopy (EDX) and X-ray Diffraction Analysis (XRD). The autoclaving was done in Runyes model B autoclave. Results. The DSC results revealed the austenite start (9.8° C; 26.47° C) and austenite finish (28° C; 31.74° C) temperatures for the as-received and autoclaved archwires respectively. For clinically retrieved samples the austenite finish temperature (Af) is around 27° C. The XRD patterns of the as-received and clinically retrieved samples show almost identical diffraction patterns. Rough surface of the CuNiTi alloy was revealed by the SEM analysis. Autoclaving process seems to have no effects on archwires’ structure and chemical composition. Chemical content of the investigated as-received CuNiTi are Ni, Ti and Cu: 47.07 wt% and 46.81 wt% and 6.11 wt%, respectively. The autoclaving process seems to have little influence on the transition temperature. The results from our study showed little difference (~7 °C) in the finish transition temperatures (Af), compared to the manufacturer’s claim. No intermediate R phase was detected by DSC. Conclusion. A good knowledge of the structural changes that occur in CuNiTi alloys in the oral cavity is useful for the orthodontists in order to optimize orthodontic treatment.

Effect of cell imprinting on viability and drug susceptibility of breast cancer cells to doxorubicin

This study demonstrates the effect of substrate's geometrical cues on viability and the efficacy of an anti-cancer drug, doxorubicin (DOX), on breast cancer cells. It is hypothesized that the surface topographical properties can mediate the cellular drug intake. Pseudo-three dimensional (3D) platforms were fabricated using imprinting technique from polydimethylsiloxane (PDMS) and gelatin methacryloyl (GelMA) hydrogel to recapitulate topography of cells’ membranes. The cells exhibited higher viability on the cell-imprinted platforms for both PDMS and GelMA materials compared to the plain/flat counterparts. For instance, MCF7 cells showed a higher metabolic activity (11.9%) on MCF7-imprinted PDMS substrate than plain PDMS. The increased metabolic activity for the imprinted GelMA was about 44.2% compared to plain hydrogel. The DOX response of cells was monitored for 24 h. Although imprinted substrates demonstrated enhanced biocompatibility, the cultured cells were more susceptible to the drug compared to the plain substrates. In particular, MCF7 cells on imprinted PDMS and GelMA substrates showed 37% and 50% higher in cell death compared to the corresponding plain PDMS and GelMA, respectively. Interestingly, the drug susceptibility of the cells on the imprinted hydrogel was about 70% higher than the cells cultured on imprinted PDMS substrates. Having MCF7 cell-imprinted substrates, DOX responses of two other breast cancer cell lines, SKBR3 and ZR-75-1, were also evaluated. The results support that cell membrane curvature developed by multiscale topography is able to mediate intracellular signaling and drug intake. Statement of SignificanceResearch in biological sciences and drug discovery mostly rely on two dimensional (2D) cell culture techniques which cannot provide a reliable physiologically relevant environment. Lack of extracellular matrix and a large shift in physicochemical properties of conventional 2D substrates can induce aberrant cellular behaviors. While chemical composition, topographical, and mechanical properties of substrates have remarkable impacts on drug susceptibility, gene expression, and protein synthesis, the most cell culture plates are from rigid and plain substrates. A number of (bio)polymeric 3D-platforms have been introduced to resemble innate cell microenvironment. However, their intricate culture protocols restrain their applications in demanding high-throughput drug screening. To address the above concerns, in the present study, a hydrogel-based pseudo-3D substrate with imprinted cell features has been introduced.

Analysis of different annealing conditions on physical properties of Bi doped CdTe thin films for potential absorber layer in solar cells

The mainstream technology used for production of high-efficiency CdTe photovoltaics involves Cu doping to CdTe absorber and CdTe/CdS junction activation by cadmium chloride (CdCl2), however, both procedures restrict their use for long term operation. With purpose of seek alternatives, herein, air and MgCl2 annealing along with CdCl2 is performed over e-beam evaporated CdTe:Bi films for their role in absorber photovoltaics. Structural properties indicate appearance of cubic (1 1 1) preferred peak where grain size is found to be affected with nature and temperature of annealing. Optical properties divulge variation in absorbance with annealing, also direct energy band gap is estimated in 1.42–1.69 eV range. All investigated films demonstrated ohmic behavior where conductivity is affected by Bi dopant. Surface morphological properties demonstrated uniform deposition with spherical-shaped grains for pristine as well as 150 °C and 300 °C air annealed films which changed to polyhedral at further annealing. Appeared Cd and Te peaks in EDS patterns validated CdTe films deposition. Surface topographical properties display ditch and dike structures for pristine and 150 °C annealing and hillock structures for higher annealing. Thus, present study imparts critical insights to air, CdCl2 and MgCl2 annealing effect on properties to CdTe:Bi films and designate that chloride treatment is less-effective during Bi doping to CdTe.

Investigation of Physiochemical and Thermal Properties of Eichhornia Crassipes Fibers

ABSTRACT The physical, chemical, structural, crystallographic, thermal and surface topographical properties of fiber extracted from the steam of Eichhornia crassipes (EC) plant was characterized for the first time in this study. Physical and chemical analysis results revealed that Eichhornia crassipes fiber (ECF) has comparatively lower density (1350 kg/m3) and higher cellulose content (59.86 wt.%). The chemical functional groups and relevant chemical composition of the ECF were documented by the FTIR. The XRD results acknowledged that ECF has the crystallinity index (44.32%) and crystalline size of 5.09 nm, respectively. Thermogravimetric analysis (TGA) and differential scanning calorimeter analysis (DSC) results of ECF exhibited that it can be thermally stable up to 200° C. All the results of ECF establish that it is a suitable substitute for the artificial fibers used as reinforcement in fiber-reinforced plastics.

IR filtering properties of TiAlN/Cu/TiAlN coatings

In this paper, to explore the potential infrared filtering applications of magnetron sputtered TiAlN/Cu/TiAlN coatings, we investigated the optical, morphological and surface topographical properties using UV/Vis/NIR spectrometry, Scanning Electron Microscopy (SEM) and Atomic Force Microscopy, respectively. From IR Spectroscopy analysis, it is observed that glass/TiAlN/Cu/TiAlN structure with 10 nm thick Cu layer showed highest visible transmittance of 78% and lowest IR transmittance of 22% at 600 nm and 2500 nm wavelength, respectively. In additon the AFM topographs further indicate that the inner TiAlN seeding layer could reduce the average roughness of Cu layer to 3 nm as compared to 8 nm without seeding layer. Moreover, outer TiAlN layer demonstrates very good environmental and corrosion protection property. Based on the results and analysis, it is proposed that TiAlN/Cu/TiAlN can be used as an efficient IR reflective material with high visible transmittance.

Characterisation of wear areas on UHMWPE total knee replacement prostheses through study of their areal surface topographical parameters

Total knee replacement is one of the most common elective surgeries in the world, and presents a number of challenges related to the wear of ultra-high molecular weight polyethylene (UHMWPE). This paper presents an analysis of the surface topographical properties of the worn and unworn condylar surfaces on a small cohort of both wear simulated and retrieved prostheses of varying designs. A number of measurement points were taken on each prostheses in a mixture of worn and unworn areas through the use of focus-variation microscopy (FVM), a non-contact method of surface measurement. Surface areal parameters were extracted from this data to analyse and search for patterns within the data. It was found that in general, worn implant surfaces appear to show smoother, less peak dominated surfaces than unworn area. It was also found that wear simulated and retrieved implants display similar characteristics of surface topography. In addition, variation was noted between different designs of TKR device, with posterior stabilised designs found to be peak dominated and cruciate retaining type implants being valley dominated.

Tribological properties of surface topography in ultrasonic vibration-assisted grinding of zirconia ceramics

In order to clarify the friction phenomenon of zirconia ceramics in the dental prosthodontics, tribological properties of surface topography in ultrasonic vibration-assisted grinding (UVAG) are studied in this work. The mechanism of material removal is researched to introduce the discontinuous grooves in UVAG theoretically. The UVAG experiments are conducted on zirconia ceramics. Through investigating and comparing experimental results, it is found that UVAG surface has better tribological properties compared with diamond grinding surface. 3D surface roughnesses of UVAG surface are improved when suitable spindle speed, large feed, small cutting depth, and large vibration amplitude are adopted. Surface topography in UVAG changes from thorn scaly to discontinuous shallow furrow when feed increases and spindle speed decreases. The discontinuous grooves are most apparent when vibration amplitude is maximum. Furthermore, the friction coefficient is experimentally studied. The results indicate that there is no significant difference among all the friction coefficients in UVAG. Proper cutting and vibration parameters can improve the average friction coefficient.

Mouse embryonic fibroblasts accumulate differentially on titanium surfaces treated with nanosecond laser pulses.

Biomaterial engineering, specifically in bone implant and osseointegration, is currently facing a critical challenge regarding the response of cells to foreign objects and general biocompatibility of the materials used in the production of these implants. Using the developing technology of the laser surface treatment, this study investigates the effects of the laser repetition rate (frequency) on cell distribution across the surface of the titanium substrates. The main objective of this research is building a fundamental understanding of how cells interact with treated titanium and how different treatments affect cell accumulation. Cells respond differently to surfaces treated with different frequency lasers. The results of this research identify the influence of frequency on surface topography properties and oxidation of titanium, and their subsequent effects on the pattern of cell accumulation on its surface. Despite increased oxidation in laser-treated regions, the authors observe that fibroblast cells prefer untreated titanium to laser-treated regions, except the regions treated with 25 kHz pulses, which become preferentially colonized after 72 h.

FACILE FABRICATION OF GRADIENT SURFACE BASED ON (METH)ACRYLATE COPOLYMER FILMS

This paper describes a simple and economic approach for fabrication of surface wettability gradient on poly(butyl acrylate – methyl methacrylate) [P (BA–MMA)] and poly(butyl acrylate – methyl methacrylate – 2-hydroxyethyl methacrylate) [P (BA–MMA–HEMA)] films. The (meth)acrylate copolymer [including P (BA–MMA) and P (BA–MMA–HEMA)] films are hydrolyzed in an aqueous solution of NaOH and the transformation of surface chemical composition is achieved by hydrolysis in NaOH solution. The gradient wetting properties are generated based on different functional groups on the P (BA–MMA) and P (BA–MMA–HEMA) films. The effects of both the surface chemical and surface topography on wetting of the (meth)acrylate copolymer film are discussed. Surface chemical composition along the materials length is determined by XPS, and surface topography properties of the obtained gradient surfaces are analyzed by FESEM and AFM. Water contact angle system (WCAs) results show that the P (BA–MMA–HEMA) films provide a larger slope of the gradient wetting than P (BA–MMA). Moreover, this work demonstrates that the gradient concentration of chemical composition on the poly(meth) acrylate films is owing to the hydrolysis processes of ester group, and the hydrolysis reactions that have negligible influence on the surface morphology of the poly(meth) acrylate films coated on the glass slide. The gradient wettability surfaces may find broad applications in the field of polymer coating due to the compatibility of (meth) acrylate polymer.

Optimization of physical properties of vacuum evaporated CdTe thin films with the application of thermal treatment for solar cells

This paper reports the optimization of physical properties of cadmium telluride (CdTe) thin films with the application of thermal treatment. The films of thickness 650nm were deposited on glass and indium tin oxide (ITO) coated glass substrates employing vacuum evaporation followed by thermal annealing in the temperature range 250–450°C. The films were characterized using X-ray diffraction (XRD), source meter and atomic force microscopy (AFM) for structural, electrical and surface topographical properties respectively. The X-ray diffraction patterns reveal that films are polycrystalline with predominant zinc-blende structure having preferred reflection (111). The structural parameters are calculated and discussed in detail. The current–voltage characteristics show Ohmic behavior and the electrical conductivity is found to increase with annealing treatment. The AFM studies show that the surface roughness of films is observed to increase with annealing. The experimental results reveal that the thermal annealing plays an important role to enhance the physical properties of CdTe thin films and annealed films may be used as absorber layer in CdTe/CdS solar cells.

Farklı yumuşak astar materyallerinin Candida albicans biyofilm formasyonu açısından değerlendirilmesi

OBJECTIVE: The purpose of this study was to evaluate Candida albicans biofilm formation on soft liners prepared against two surfaces with different properties. MATERIALS AND METHOD: Four soft liners (Molloplast B, Permafleks, Elite-soft, Ufi Gel P) were prepared against glass or dental plaster surfaces (5x5x2 mm; n=5). The surface roughness and contact angle of the soft liner specimens were measured. Candida albicans ATCC 10231 was grown in Sabouraud dextrose broth (SDB) at 37 °C for 24 h. For biofilm formation, the specimens were incubated in polystrene wells together with fresh SDB and the C. albicans culture at 37 °C for 48 h. The specimens were stained with 0.1% crystal violet and dehydrated at 65 °C. The quantification of the C. albicans biofilm formation was performed spectrophotometrically. Comparison of the surface roughness, contact angle and biofilm formation between the materials was done using one way ANOVA and Tukey tests. Correlation between surface roughness, contact angle and biofilm formation on the specimens prepared against glass or plaster surfaces was performed using Pearson correlation analysis. RESULTS: Specimens prepared against plaster showed significantly higher surface roughness, contact angle and biofilm formation values in comparison to those prepared against glass surface (p 0.05). CONCLUSION: Although the soft liners tested in this study had similar surface topographic properties, they showed different amounts of C. albicans biofilm formation. Smooth surfaces were found to reduce the biofilm formation.

Effects of Laser Pulse Numbers on Surface Biocompatibility of Titanium for Implant Fabrication

Generally, materials with high biocompatibility are more appropriate for bone and tissue transplant applications, due to their higher effectiveness in the healing process and infection problems. This study presents the effects of laser surface texturing on the surface topography properties, roughness, and wettability of thin titanium sheets, which consequently enhance the biocompatibility of this material. Creating line patterns across the surfaces, the titanium samples are prepared using variety of laser parameters. The apatite inducing ability of each sample is tested through the use of simulated body fluid (SBF). The final biocompatibility level of titanium samples is analyzed through wettability, surface angle measurements, and average surface temperature profile. Overall, the effects of laser parameter, pulse numbers, upon the biocompatibility of titanium are thoroughly examined, with results indicating that a scanning speed of 100 μm/ms results in desirable bone type apatite inducing abilities across the surface of treated titanium sheets.

Modelling of surface roughness effects on impurity erosion and deposition in TEXTOR with a code package SURO/ERO/SDPIC

The roughness-induced uneven erosion–deposition behaviour is widely observed on plasma-wetted surfaces in tokamaks. The three-dimensional (3D) angular distribution of background plasma and impurities is expected to have an impact on the local erosion–deposition characteristic on rough surfaces. The investigations of 13C deposition on rough surfaces in TEXTOR experiments have been re-visited by 3D treatment of surface morphology to evaluate the effect of 3D angular distribution and its connection with surface topography by the code package SURO/ERO/SDPIC. The simulation results show that the erosion/deposition patterns and evolution of surface topography are strongly affected by the azimuthal direction of incident flux. A reduced aspect ratio of rough surface leads to an increase in 13C deposition due to the enhanced trapping ability at surface recessions. The shadowing effect of rough surface has been revealed based on the relationship between 3D incident direction and surface topography properties. The more realistic surface structures used by 3D SURO can well reproduce the experimental results of the increase in the 13C deposition efficiency by a factor of 3–5 on a rough surface compared with a smooth one. The influence of sheath electric field on the local impact angle and resulting 13C deposition has been studied, which indicates that the difference in 13C deposition caused by sheath electric field can be alleviated by the use of more realistic surface structures. The difference in 13C deposition on smooth graphite and tungsten substrates has been specified by consideration of effects of kinetic reflection, enhanced physical sputtering and nucleation.