Search

In this paper, the implementation and testing of multilayer graphene/epoxy resin nanocomposites are discussed. Firstly, the epoxy resin hardener is mixed with the multilayer graphene, and then mixed with the main agent, then poured into the mold, and the low temperature cooling system is used. The curing time of the epoxy resin is slowed down, and the bubble is removed before the complete hardening by the vacuum defoaming method, and the mechanical properties such as tensile strength and toughness are compared with the pure epoxy resin after being sufficiently hardened. In this paper, we investigated the effect of multilayer graphene content on mechanical properties by using the tensile test and impact test. We discussed the effect of multilayer graphene content on the coefficient of elasticity of the multilayer graphene/epoxy resin composites at different stretching rates. And the toughness of the multilayer graphene/epoxy resin composites was evaluated by impact test. After the experiment, it was found that the stretching rate has a certain degree of influence on the grapheme/epoxy resin composite material. And that the addition of 2% multilayer graphene to epoxy resin had the best effect and could effectively improve the coefficient of elasticity and toughness.

This study proposed a dynamic forming mechanism development of the negative Poisson’s ratio elastomer molds—plate to plate (P2P) forming process. To dynamically stretch molds and control the microstructural shape, the proposal is committed to using the NPR structure as a regulatory mechanism. The NPR structural and dynamic parallel NPR-molds to control microstructure mold-cores were simulated and analyzed. ANSYS and MATLAB were used to simulate and predict dynamic NPR embossing replication. The hot-embossing and UV-curing dynamic NPR P2P-forming systems are designed and developed for verification. The results illustrated that the dynamic forming mechanism of the negative Poisson’s ratio elastomer molds proposed by this study can effectively control microstructure molds. This can effectively predict and calculate the geometrical characteristics of the microstructures after embossing. The multi-directional dynamic NPR microstructural replication process can accurately transfer microstructures and provide high transfer rate-replication characteristics.

This study was based on an atomic force microscopy (AFM) to study the nanotribological property of Cr---N---Cu nanocomposite thin film under air and deionized (DI) water environment. Using the force curve test to get the normal force of probe, and the friction force was measured by the loop method. And then nanotribological experiments can be carried out under air and deionized (DI) water environment by a AFM. After Nanotribological experiments, we found that the coefficient of friction (COF) value of Cr---Cu---N nanocomposite thin film in DI water is significantly higher than that in air. And it can be found that whether in the air or DI water, the tip speed increases, the COF value decreases. In the air, the normal force increases, the COF value also increases, but, a different trend is observed in DI water.

This paper has successfully constructed the multilayer nano thin film deposition simulation model with molecular dynamics under the effect of gravity in a vacuum environment. Simulation results show that under gravity environment, the surface morphology becomes less flat, and the internal stress are larger. In higher deposition rate, the internal stress also increases, and the surface morphology of the thin film becomes, the more uneven. As the increase of substrate temperature, the internal stress of deposited nano thin film is reduced but the interfacial bonding energy is an increase. And the higher the substrate temperature, the surface topography is more flatten.

This study used porous alumina membranes with nanopores as nanopore channels and successfully constructed a single-stage/multistage nanotube electroosmotic micropump. The characteristics of electroosmotic nanotubes pump constructed using porous alumina membranes with varying pore sizes and at different stages were also analyzed. During the experiments, applying a multistage nanotube electroosmotic micropump with the same pore size at the two stages yielded a superior performance curve compared to that of the single-stage nanotube electroosmotic micropump. The flow volume and pressure difference of the pump increased rapidly with the input voltage. Thus, the flow volume of multistage nanotube electroosmotic micropump with the same pore size can be increased more than twice that of single-stage pumps. With a high input voltage, the multistage micropump showed a significant, approximately 4-fold increase.

This study mainly investigates the influence of electronic water cooling system on high power heat generation device at different cooling water inlets with vortex fins or not, hence, heat dissipation experiments are going to carried out on the conditions of three cooling cases: hollow case I, hollow case II and vortex-fin case. From this experiment, it can be seen that the heat dissipation efficiency of hollow case I is reduced by 10% as compared to that of hollow case II, and the heat dissipation efficiency of vortex-fin case is also reduced by 10% as compared to that of hollow case I, that is, water cooling system with vortex-fin has very excellent effect on heat dissipation.

Summary: This study focused on the nanomachining property and cutting model of single-crystal sapphire during nanomachining. The coated diamond probe is used to as a tool, and the atomic force microscopy (AFM) is as an experimental platform for nanomachining. To understand the effect of normal force on singlecrystal sapphire machining, this study tested nano-line machining and nano-rectangular pattern machining at different normal force. In nano-line machining test, the experimental results showed that the normal force increased, the groove depth from nano-line machining also increased. And the trend is logarithmic type. In nano-rectangular pattern machining test, it is found when the normal force increases, the groove depth also increased, but rather the accumulation of small chips. This paper combined the blew by air blower, the cleaning by ultrasonic cleaning machine and using contact mode probe to scan the surface topology after nanomaching, and proposed the “criterion of nanomachining cutting model,” in order to determine the cutting model of single-crystal sapphire in the nanomachining is ductile regime cutting model or brittle regime cutting model. After analysis, the single-crystal sapphire substrate is processed in small normal force during nano-linear machining; its cutting modes are ductile regime cutting model. In the nano-rectangular pattern machining, due to the impact of machined zones overlap, the cutting mode is converted into a brittle regime cutting model. SCANNING 36:599–607, 2014. © 2014 Wiley Periodicals, Inc.

This study focused on the ultrasonic nanomachining by atomic force microscopy (AFM) to understand the phenomena of the ultrasonic nanomachining. The workpiece is an Au/Ti thin film and coated on the quartz crystal resonator (QCR). The ultrasound vibration of workpiece is carried out by used the Quartz crystal microbalance (QCM). And a normal force measurement model was built by force curve measurements in ultrasound vibration environment. The influence of different experimental parameters can be studied such as normal force and repeat number on the cutting depth and chip stacking. After the experiments, it can be found that the ultrasonic nanomachining by AFM is possessed great influence on the cutting depth.

This study successfully simulated the single crystal copper nanocutting by a rigid body /elastic tools with nose radius at the nitrogen gas environment using molecular dynamics, and analyzed the workpiece temperature distribution and dislocation during nanocutting. After simulations, it can be found that when cutting with the elastic body tool, the tool itself was still distorted slightly, however, the cutting results of the elastic tool and the rigid body tool of the tool are not the same. The chip temperature was highest near the central rake and nose.The workpiece temperature when the elastic body tool cutting was lower; the temperature in the nose and rake plane is the highest, the more away from the nose, the lower the temperature.

In this paper, the nanomachining experiments on the SPR3001 photoresistor thin films were processing by contact mode atomic force microscopy (AFM). After the experiment, it can be found, in the nanomachining, the greater the indented distance along the Z-axis depth, carved out of the groove depth and groove width of nanoline is greater. The influences of cutting directions on line width and cutting depth during nanomachining were quite a few and the cutting situation was stable by lateral nanomachining. This article also successfully processed the regular hexagonal nanopattern, also proves the nanomachining ability of the AFM probe is good at nanoscale patterned on photoresistor thin films.

This paper mainly focuses in the use of an atomic force microscope, research about the nanooxidation technique of conductive diamond-like carbon thin film in the atmospheric environment. The hardness, high wear resistance and chemical stability of diamond-like carbon thin film is high, and coefficient of friction is low, it is very suitable as a mold material for nanoscale mold. However, tool can only use a diamond cutter to machine the high hardness diamond-like carbon by traditional hard machining method, and tool life is not long. To overcome this drawback, the paper proposed an atomic force microscope (AFM) as a platform, a conductive AFM probe for tool under atmospheric conditions, and imposed nanooxidation technique on conductive diamond-like carbon thin film using electroluminescent etching to carry out nanofabrication processing. During the nanofabrication process, by changing the various processing parameters, such as applied voltage, repeated nanooxidation times and probe speed, etc., in order to understand the effect of processing parameters. The experimental results show, the nanooxidation technique can be carried out nanofabrication on conductive diamond-like carbon thin film successfully. And found that applied voltage, repeated nanooxidation times and probe speed all for the groove depth on the conductive diamond-like carbon thin films have significant influence. Additionally, this study successfully created a nanopattern. Therefore, the adequate machinability of DLC coating was achieved successfully in this study, indicating a promising application in the fabrication of nanopatterns on a nanoscale.

This study focused on the combination of atomic force microscopy (AFM) and quartz crystal microbalance (QCM) to construct the ultrasound assisted AFM base nanomachining experimental platform, and to construct the experimental planning of ultrasonic assisted nanomachining, to understand the phenomena of the ultrasound assisted AFM base nanomachining. Firstly, we combined the AFM and QCM to construct the ultrasound assisted AFM base nanomachining experimental platform. And a normal force measurement model was built by force curve measurements in ultrasound vibration environment. Next, the ultrasonic assisted nanomachining was carried out and aimed at brittle and ductile materials to probe into the influence of different experimental parameters such as probe speed, normal force and workpiece material on the cutting depth, width and chip stacking. After the experiments, it is succeeded in the ultrasound assisted AFM base nanomachining experimental platform in this study. And it can be found that the ultrasonic assisted nanomachining is possessed great influence on the cutting depth and width.

In this paper, it based on the ideal gas conditions in the Maxwell velocity distribution and considering only the elastic collisions between gas molecules to study the distribution of gas molecules in the gravity field as a means of computer simulation. The simulation results show the process of molecular movement and distribution patterns. And it can be found that the distribution of gas molecules in the gravity field distribution is determined by the frequent collisions between molecules and it has nothing to do with the velocity and the initial position of molecules. In addition, the simulation also reveals the Boltzmann distribution law is a statistical regularity in terms of the large number of particles. The ideal gas elastic collision simulation software can increase intuitive awareness of students on the knowledge, and to provide an effective adjunct to consolidate what they have learned.

This study successfully simulated the single crystal copper nanocutting with a rigid body tool at the nitrogen gas environment using molecular dynamics, and analyzed the workpiece stress distribution and dislocation during nanocutting. After simulations, a diamond rigid tool with a completely sharp produce a shear plane during cutting. The distribution of equivalent stress was greatest at the shear zone and that residual stress occurred on the machined surface. And the stress gets smaller as the distance from the chip surface is farther.

The Youngs modulus of multilayered nanothin films is an important property. This paper focused to investigate the Youngs Modulus of Multilayered Ni/Cu Multilayered nanoThin Films under different condition by Molecular Dynamics Simulation. The NVT ensemble and COMPASS potential function were employed in the simulation. The multilayered nanothin film contained the Ni and Cu thin films in sequence. From simulation results, it is found that the Youngs modulus of Cu/Ni multilayered nanothin film is different at different lattice orientations, temperatures and strain rate. After experiments, it can be found that the Youngs modulus of multilayered nanothin film in the plane (100) is highest. As thickness of the thin film and system temperature rises, Youngs modulus of multilayered nanothin film is reduced instead. And, the strain rate increases, the Youngs modulus of Cu/Ni multilayered nanothin film will also increase.

Micro-deep drawing process combined with ultrasonic vibration were performed on three stainless steel 304 foils of different thicknesses to determine the influence of ultrasonic vibrations on micro-cup formability and the limit drawing ratio (LDR). An ultrasonic system that applies 20 kHz of oscillation at various amplitudes was developed, and a concentrator was used to transfer the oscillation from the transducer to the die. The LDRs of these foils were obtained with and without ultrasonic variations. The experimental results in this study showed that using ultrasonic vibration following the deep drawing processes increased the LDR from 1.67 to 1.83, from 1.75 to 1.92, and from 1.83 to 2 for thicknesses of 50, 75, and 100 μm, respectively. The oscillation amplitudes had a significant effect on different thicknesses. An amplitude of 8.6 μm could not be appropriately applied to foils because of the excessive oscillated force. The punch force also decreased as the oscillation amplitude increased because of reduced friction between the die and the blank. Based on these experimental results, this study showed that ultrasonic vibrations can be used to produce micro-cups that exhibit high application flexibility in miniaturization technology.

This study constructed an ultrasound-assisted AFM nanomachining platform by integrating an atomic force microscope (AFM) with a quartz crystal microbalance, which was subsequently used in experiments for determining the microscopic phenomena of ultrasound-assisted nanomachining. Force-distance curve measurement was used to establish a normal force measurement model, obtaining the downforce strengths during ultrasound-assisted nanomachining. Subsequently, machining experiments were conducted on monocrystalline silicon to explore the effects of various experimental parameters (e.g., machining speed and normal force) on machining depth. The experiments showed that the ultrasound-assisted AFM nanomachining platform constructed in this study is effective. After ultrasound was incorporated, monocrystalline silicon specimens made of brittle material could be more effectively processed under various experimental parameters. Moreover, the performance of ultrasound-assisted nanomachining was superior to that of general nanomachining.

This study conducted nano-oxidation experiments in an exploration of applied voltage, time of voltage application, and relative humidity, in order to establish a nano-oxidation processing database. Multiple regression analysis (MRA) was then used to construct the impact of nano-oxidation process parameters on the oxide weight and height relationship. Finally, this study conducted a confirmation experiment and explored the impact of additional parameter amplification on the predictive power of the relationship equation. It was found that the relationship equation of the oxide height and width generated by combining the nano-oxidation processing database and the process parameters obtained using MRA was quite reasonable, and that the addition of database parameters that are in line with physical meaning could improve the predictive power of the relationship equation.

This study explored the tribological phenomena under minimal load using molecular dynamics. In the simulation, ensemble average standards and the Condensed-phase Optimized Molecular Potential for Atomistic Simulation Studies potential energy function were used. Regarding materials, this study used (5, 5) carbon nanotubes (CNTs) to move the copper atoms in order to obtain the coefficient of friction (COE) between the single-wall CNTs and copper atoms before analyzing the tribological phenomena under minimal load and changes in friction. This study found that, under an extremely tiny load, the direction of the resistance of the relative sliding is not always in the opposite direction of the movement direction. The influence of environment temperatures on the COE was that the environment temperature increases, the number of fluctuation also increases, but the COE reduces.

article i nfo Available online 18 January 2012 Fluorinated diamond-like carbon (F-DLC) films were deposited on Ti6Al4V substrates by radio frequency plasma enhanced chemical vapor deposition (rf PECVD) technique using a mixture of methane (CH4) and tet- rafluoromethane (CF4) gasses. A 100 nm Si interlayer was coated in advance by physical vapor deposition (PVD) to improve the adhesion between F-DLC and Ti alloy. A 200 nm TiN-coated specimen with the same Ti6Al4V substrate was also built by PVD as a benchmark. The structure and surface properties of F-DLC coat- ings, prepared with various fluorine flow ratios, were investigated by using X-ray photoelectron spectrosco- py, scanning electron microscopy, atomic force microscopy, liquid drop goniometry, and electrochemical corrosion tests. The blood compatibility was evaluated by measuring haemolysis ratio and platelet-covered area in vitro. The films' spectroscopic results show that the CFx group and fluorine atomic concentration in- crease as CF4 flow ratio is promoted in the mixture. The surface energy is reduced due to the increased fluo- rine content. The modified surfaces are characterized by higher hydrophobicity, lower thrombogenicity, and better corrosive protection than the virgin and TiN ones.

This study developed carbon dioxide (CO2)-assisted hot embossing molding technology using the penetration of SCF (supercritical fluid), as generated by CO2 in a high pressure process, into the high polymer plastic substrate in order to realize the plasticization phenomenon. At the glass transition temperature (Tg), microstructure array elements were molded by hot embossing replication, and the optical effects of the formed microstructure were discussed. This study first developed the SCF hot embossing system equipment by evenly infiltrating the plastic substrate through the SCF phenomenon generated by CO2 under high pressure. Using the characteristics of the CO2-aided uniform imprinting technology, this study discussed the microstructure replication moldability and optical effects of the microstructure at the Tg temperature. The results suggested that the SCF hot embossing system proposed in this study can successfully transliterate the microstructure onto the photo-resist at Tg temperature. This study al...

This paper studies the deposition process and mechanical properties of Cu thin films deposited on single crystal copper substrates with various surface roughnesses by molecular dynamics (MD). In the effect of vacancy concentration (Cv) of substrate, the Young's modulus of sample decreased as the Cv of substrate increased but the adhesion force will increase as the Cv of substrate increases. The effect of substrate roughness on the peak intensity of crystal orientation has little. And the greater Cv of substrate, the surface roughness of the deposited thin film also increased. In the effect of numbers of deposited atoms, the deposited thin film thickness increases, the surface will be relatively flat and the Young's modulus will also increase. By the XRD pattern, the principal growth directions of thin film are the (220) and (200) in the early stage of growth during deposition. However, with the thickness increasing, the (111) will be the preferred orientation.

Fluorinated amorphous diamond-like carbon (F-DLC) films were deposited on Ti6Al4V substrates by radio frequency plasma enhanced chemical vapor deposition (rf PECVD) technique using a mixture of methane (CH4) and tetrafluoromethane (CF4) gasses. A 100 nm Si interlayer was coated in advance by physical vapor deposition (PVD) process to improve the adhesion between F-DLC and Ti alloy. The structure and surface properties of F-DLC coatings, prepared by various fluorine flow ratios, were investigated by using X-ray diffraction spectroscopy, Raman spectroscopy, Fourier transform infrared spectroscopy, X-ray photoelectron spectroscopy, and scanning electron microscopy. The mechanical properties were evaluated by nano-indentation, and the adhesion, by micro-scratch. The results showed that a moderate incorporation of the fluorine content in the DLC films can still maintain acceptable mechanical properties, which, on the other hand, obtains remarkable benefits of blood compatibility and anti-corrosion.

This study investigated the microstructural characteristics, metallurgy, microhardness, and tensile strength of AZ31 and AZ61 magnesium alloy weldments, fabricated in a CO2 laser welding process with the adjustment of various parameters. The results show that the AZ31 weldment contains equiaxed grains within the fusion zone (FZ). By contrast, the FZ of the AZ61 weldment contains refined cellular grains and the partially melted zone (PMZ) contains bulk grains. We infer that the difference in aluminum content between the two magne- sium alloys results in different supercooling rates and solid grain structures. For both weldments, the ultimate tensile strength (UTS) de- creases following the CO2 laser welding process. However, no significant difference is noted between the UTS of the two weldments, sug- gesting that tensile strength is insensitive to the Al content of the magnesium alloy. The CO2 laser welding process is shown to increase the microhardness of both magnesium alloys. Furthermore, grain refinement is responsible for the maximum hardness in the FZ of both weld- ments. The AZ61 weldment has a higher content of Al, resulting in a greater grain refinement.

In this study, the microstructure and glass transition temperature (Tg) of five elements (Al-Cu-Cr-Fe-Ni) high-entropy alloy was evaluated under different Al content by molecular dyItalic textnamics (MD) simulations. The ensemble and COMPASS potential were used. Firstly, the Al-Cu-Cr-Fe-Ni high-entropy alloys were melted at high temperature and were cooled with a high quenching rate further. The radial distribution function (RDF),Wendt-Abraham parameter and X-ray diffractometer (XRD) were used to analyze the change on the microstructure and glass transition temperature (Tg) of Al-Cu-Cr-Fe-Ni high-entropy alloys. Simulation results show that the micro-structure of different aluminum content of AlxCuCrFeNi alloy after fast quenching are all amorphous state. When the aluminum content decreased, the amorphous state are more obvious and the glass transition temperature decreases.

The hybrid drilling command was proposed in this study. The hybrid drilling command is established by combined the merit of G73 (high speed peck drilling cycle) and G83 (small hole peck drilling cycle) using custom macro command. The concept of hybrid drilling command is to divide the total drilling depth into several distances and its distance is shortened gradually. The drilling chip is breaking with the G73 in the distance between each one and banishing from the hole with the G83 after drilling a distance each time. The evaluation on the merit of hybrid drilling command was carried out by deep hole drilling test on CNC machine center. After experiments, the hybrid drilling command can reduce wearing, extending the tool life of the driller and shorten processes time.

This study proposes the combination of electrochemical tip sharpening, mirror wax plate production, computer numerical control (CNC) imprinting technology, and the polydimethylsiloxane (PDMS) vacuum casting method to produce an innovative process akin to the setae arrangement in gecko feet to create a large-area gecko seta-like structure or gecko tape. This study produced micrometer tip radius probes using electrochemical methods and used CNC to apply imprinting technology to imprint a micrometer pore structure on the mirror wax plate (substrate) via micro-scale probes to be covered with a micro-porous structure of the wax mold, conducting the vacuum casting method by PDMS to create a gecko tape shaped like gecko feet. The results show that the surface roughness of the mirror wax plate produced in this study reaches the nanoscale. After electrochemical tip sharpening, the tip radius of the 0.5 mm tungsten rod can be reduced to less than 10 μm. The finished gecko tape indicates that using a wax mold to conduct PDMS vacuum casting creates good formability. This indicates the innovative gecko seta-like tape process proposed in this study is greatly feasible. It was also found that the adhesion force increased with the increase of the number of pillars and the increased pillars height of the gecko tape. The average adhesion force of a single pillar, however, decreases with an increase in the number of pillars.

This study investigates the microstructure, hardness, and tensile strength of AZ31 and AZ61 magnesium alloy weldments fabricated in a CO 2 laser welding process. Results show that the AZ31 weldment contains cellular grains within the fusion zone (FZ). By contrast, the FZ of the AZ61 weldment contains a mixture of cellular and columnar grains and the PMZ contains bulk grains. It can be inferred that differences in the aluminum content of the two alloys (i.e., AZ31: 2.66 wt%; AZ61: 5.25 wt%) results in different supercooling rates and solid grain structures. The aluminum content also influences the formation of precipitates and defects in the weld bead during solidification, due to altered cooling rates resulting from thermal effects triggered by the growth of the precipitation phase. In particular, the AZ61 weldment exhibits high microporosity in the PMZ region with micropores or voids at the bottom of the weld bead. It is speculated that these defects are the result of liquation cracking. CO 2 laser welding has been shown to increase the hardness of both magnesium alloys, with the maximum hardness occurring in the FZ of both weldments due to grain refining. The AZ61 weldment has the higher hardness of the two, due to increased grain refinement resulting from higher Al content. For both weldments, the ultimate tensile strength (UTS) decreases following CO 2 laser welding. However, no significant difference was noted between the UTS of the two weldments, suggesting that tensile strength is insensitive to the Al content of the magnesium alloys. By contrast, the uniform elongation increases with an increase in Al content in these alloys, indicating that the uniform elongation of the two weldments is sensitive to the Al content. Finally, the two weldments exhibit different fracture behavior resulting from differences in the size of the supersaturated precipitates formed in the two specimens and the presence of micropores and voids in the AZ61 specimen.

High-entropy alloys have been studied extensively for their excellent properties and performance, including outstanding strength and resistance to oxidation at high temperatures. This study employed molecular dynamics simulation to produce a high-entropy alloy containing an equal molar ratio of Al, Co, Cr, Fe, and Ni and investigated the tribological behavior of the material using a diamond tool in a vacuum environment. We also simulated a AlCoCrFeNi high-entropy alloy cooled from a high temperature molten state to 300 K in a high-speed quenching process to produce an amorphous microstructure. In a simulation of nanoscratching, the cutting force-distance curve of high-entropy alloys was used to evaluate work hardening and stick-slip. An increase in temperature was shown to reduce the scratching force and scratching resistance. Nanoscratching the high-entropy alloy at elevated temperatures provided evidence of work hardening; however, the degree of work hardening decreased with an increase in temperature. And it can also be found that when the temperature is higher, the fluctuation of the cutting force curve is greater.

This study investigates the surface conditions of silicon wafers with native oxide layers (NOL) or hydrogen passivated layers (HPL) and how they influence the processes of nano-oxidation and wet etching. We also explore the combination of nano-oxidation and wet etching processes to produce nanostructures. Experimental results reveal that the surface conditions of silicon wafers have a considerable impact on the results of nano-oxidation when combined with wet etching. The height and width of oxides on NOL samples exceeded the dimensions of oxides on HPL samples, and this difference became increasingly evident with an increase in applied bias voltage. The height of oxidized nanolines on the HPL sample increased after wet etching; however, the width of the lines increased only marginally. After wet etching, the height and width of oxides on the NOL were more than two times greater than those on the HPL. Increasing the applied bias voltage during nano-oxidation on NOL samples increased both the height and width of the oxides. After wet etching however, the increase in bias voltage appeared to have little effect on the height of oxidized nanolines, but the width of oxidized lines increased. This study also discovered that the use of higher applied bias voltages on NOL samples followed by wet etching results in nanostructures with a section profile closely resembling a curved surface. The use of this technique enabled researchers to create molds in the shape of a silicon nanolens array and an elegantly shaped nanoscale complex structures mold.

Summary This study used nano-oxidation lithography to create oxidized circular nanostructures on a silicon wafer with a native oxide layer (NOL). We also investigated the impact of wet etching on the size of circular oxidized nanostructures and examined how the method and duration of preservation affect them. Experimental results show that the height and width of oxidized circular nanostructures increase proportionally with applied voltage. After wet etching, an increase in applied voltage resulted in a marked increase in the width of the circular nanostructures, a decrease in the inner diameter, and little variation in height. We further demonstrated that in a moist environment, the oxidation process continues, resulting in a further increase in height and width. During the initial stages of preservation, these changes occurred rapidly; however, the increase was negligible after 30 days. We propose the concept of reaction area (RA) ratio to explain the above phenomenon and provide evidence to support these claims. Our results led us to a simple and yet effective method of preserving oxidized circular nanostructures, called the electrostatic patch preservation (EPP) method, to overcome problems associated with changes in size occurring during the preservation of silicon nanostructure molds. SCANNING 34: 347–356, 2012. © 2012 Wiley Periodicals, Inc.

Atomic force microscopy (AFM) was used for visualization of a nano-oxidation technique performed on diamond-like carbon (DLC) thin film. Experiments of the nano-oxidation technique of the DLC thin film include those on nano-oxidation points and nano-oxidation lines. The feature sizes of the DLC thin film, including surface morphology, depth, and width, were explored after application of a nano-oxidation technique to the DLC thin film under different process parameters. A databank for process parameters and feature sizes of thin films was then established, and multiple regression analysis (MRA) and a back-propagation neural network (BPN) were used to carry out the algorithm. The algorithmic results are compared with the feature sizes acquired from experiments, thus obtaining a prediction model of the nano-oxidation technique of the DLC thin film. The comparative results show that the prediction accuracy of BPN is superior to that of MRA. When the BPN algorithm is used to predict nano-point machining, the mean absolute percentage errors (MAPE) of depth, left side, and right side are 8.02%, 9.68%, and 7.34%, respectively. When nano-line machining is being predicted, the MAPEs of depth, left side, and right side are 4.96%, 8.09%, and 6.77%, respectively. The obtained data can also be used to predict cross-sectional morphology in the DLC thin film treated with a nano-oxidation process.

This study used atomic force microscopy (AFM), metallic probes with a nanoscale tip, and high-voltage generators to investigate the feasibility of high-voltage nano-oxidation processing in deionized water (DI water) and atmospheric environments. Researchers used a combination of wire-cutting and electrochemical etching to transform a 20-μm-thick stainless steel sheet into a conductive metallic AFM probe with a tip radius of 60 nm, capable of withstanding high voltages. The combination of AFM, high-voltage generators, and nanoscale metallic probes enabled nano-oxidation processing at 200 V in DI water environments, producing oxides up to 66.6 nm in height and 467.03 nm in width. Oxides produced through high-voltage nano-oxidation in atmospheric environments were 117.29 nm in height and 551.28 nm in width, considerably exceeding the dimensions of those produced in DI water. An increase in the applied bias voltage led to an apparent logarithmic increase in the height of the oxide dots in the range of 200-400 V. The performance of the proposed high-voltage nano-oxidation technique was relatively high with seamless integration between the AFM machine and the metallic probe fabricated in this study.

This study used the nanoindenter to perform indentation tests on copper bulk and nano copper film in order to discuss the mechanical properties of pure copper at the nano scale. This study tested 7 levels of load, ranging from 20 to 200 μN (load increment at 30 μN) for the indentation tests on copper bulk and nano copper film specimens. Results showed that the load was roughly proportional to the residual depth, in the case of flat nano copper film, while the relationship between the load and the residual depth was not significant in the case of unsmooth copper bulk. Moreover, the hardness of both the copper bulk and the nano copper film would increase along with increasing load, while the Er value change trends of both the copper bulk and the nano copper film specimens differed with increasing load.

This study proposes an innovative atomic force microscopy (AFM) based nanoscale electrical discharge machining (AFM-based nanoEDM) system which combines an AFM with a self-produced metallic probe and a high-voltage generator to create an atmospheric environment AFM-based nanoEDM system and a deionized water (DI water) environment AFM-based nanoEDM system. This study combines wire-cut processing and electrochemical tip sharpening techniques on a 40-µm thick stainless steel sheet to produce a high conductive AFM probes, the production can withstand high voltage and large current. The tip radius of these probes is approximately 40 nm. A probe test was executed on the AFM using probes to obtain nanoscales morphology of Si wafer surface. The silicon wafer was as a specimen to carry out AFM-base nanoEDM process in atmospheric and DI water environments by AFM-based nanoEDM system. After experiments, the results show that the atmospheric and DI water environment AFM-based nanoEDM systems operate smoothly. From experimental results, it can be found that the electric discharge depth of the silicon wafer at atmospheric environments is a mere 14.54 nm. In a DI water environment, the depth of electric discharge of the silicon wafer can reach 25.4 nm. This indicates that the EDM ability of DI water environment AFM-based nanoEDM system is higher than that of atmospheric environment AFM-based nanoEDM system. After multiple nanoEDM process, the tips become blunt. After applying electrochemical tip sharpening techniques, the tip radius can return to approximately 40 nm. Therefore, AFM probes produced in this study can be reused. SCANNING 34: 191–199, 2012. © 2011 Wiley Periodicals, Inc.

In this study, nanoscratching and nanomachining were conducted using an atomic force microscope (AFM) equipped with a doped diamond-coated probe (DDESP-10; VEECO) to evaluate the fabrication of nanopatterns on hard, Cr2N/Cu multilayer thin films. The influence of normal force, scratch speed, and repeated scratches on the properties of hard multilayer thin films was also investigated. The nanoscratch experiments led researchers to establish a probe preparation and selection criteria (PPS criteria) to enhance the stability and accuracy of machining hard materials. Experimental results indicate that the depth of grooves produced by nanoscratching increased with an increase in normal force, while an increase in the number of scratches in a single location increased the groove depth but decreased friction. Therelationships among normal force and groove depth more closely resembled a logarithmic form than other mathematical models, as did the relationship between repeated scratching and its effect on groove depth and friction. The influence of scratch speed on friction was divided into two ranges. Between 0.1 and 2 µm/s, friction decreased logarithmically with an increase in scratch speed; however, when the speed exceeded 2 µm/s, the friction appeared stable. In this study, multilayered coatings were successfully machined, demonstrating considerable promise for the fabrication of nanopatterns in multilayered coatings at the nanoscale. SCANNING 34: 51–59, 2012. © 2011 Wiley Periodicals, Inc.

Recently, enhance the mechanical property of nanocomposite were used by adding the nanotubes. The mechanical properties of the nanocomposite were affected by interfacial bonding energy between nanotubes and polymers. In this paper, the interfacial bonding energy and Young's moulds of single-walled nanotube (SWNT) reinforced epoxy composites were investigated using molecular dynamics (MD) simulations based on a cured epoxy resin model, which was constructed by incorporating three-dimensional crosslinks formed during curing reaction. The structure types of SWNT include the armchair, zigzag and chiral was used in this study. After simulation, adding SWNT in the epoxy resin really has been reinforced effect, and the larger chiral angle of SWNT the better to strengthen. The study also calculated the interfacial bonding energy between the epoxy and the SWNT affects the ability of strengthening to the composite of SWNT. Within the range of 273K-473K, the temperature has a little influence on Young's moulds of SWNT reinforced epoxy composites.

To prevent Co diffusion from cemented carbides at high temperatures, we fabricated TaNx coatings by reactive direct current (d.c.) magnetron sputtering onto 6 wt.% cobalt cemented carbide substrates, to form diffusion barrier layers. Varying the nitrogen flow ratio, N2/(Ar + N2), from 0.05 to 0.4 during the sputtering process had a significant effect on coating structure and content. Deposition rate reduced as the nitrogen flow ratio increased. The effects of nitrogen flow ratio on the crystalline characteristics of the TaNx coatings were examined by X-ray diffraction. The TaNx coatings annealing conditions were 500, 600, 700, and 800 °C for 4 h in air. We evaluated the performance of the diffusion barrier using both Auger electron spectroscopy depth-profiles and X-ray diffraction techniques. We also investigated oxidation resistance of the TaNx coatings annealed in air, and under a 50 ppm O2–N2 atmosphere, to evaluate the fabricated layers effectiveness as a protective coating for glass molding dies.

Five nanostructured Cr 2 N/Cu multilayer coatings were deposited by a bipolar asymmetric reactive pulsed DC magnetron sputtering system, and various bilayer periods (Λ) were achieved by controlling the holding time of Si substrates in the plasma of Cr or Cu. The hardness and elastic modulus of multilayer coatings were investigated by means of a nanoindenter. Nano-scratch and nano machining experiments on multilayered coatings were conducted using atomic force microscopy (AFM) in air and DI-water, respectively. According to the groove depth, width , and coefficient of friction (COF) obtained from nano-scratch tests, influences of scratch cycle numbers and bilayer periods on the scratchability of Cr 2 N/Cu multilayered thin films were examined. It was observed that after nano-scratch experiments in air and water, the COF values and the amount of removed material increased with increasing bilayer period. After nano-machining tests in air and water, different types of the cutting chip pile-ups were observed. In this work, the surface tribological properties and machinability of Cr 2 N/Cu multilayered thin films when using an AFM are discussed.

At present, applying a near-field optical microscope to photolithographic line segment fabrication can only obtain nanoscale line segments of equal cutting depths, and cannot result in 3D shape fabrication. This study proposes an innovative line segment fabrication model of near-field photolithography that adjusts an optical fiber probe's field distance to control the exposure energy density, and moreover constructs an exposure energy density analysis method of the innovative photolithographic line segment fabrication. During the exposure simulation process of the innovative line segment fabrication model of near-field photolithography, the near-field distance between the optical fiber probe and the photoresist surface increases gradually, whereas the exposure energy density distribution decreases gradually. As a result, the cutting depth becomes shallower and the full-width at half maximum (FWHM) increases. The results of this study can serve as a theoretical reference for developing advanced nanoscale near-field photolithography techniques, to which an important and groundbreaking contribution is made.

Electrochemical polish technology could enhance the chemo-mechanical polishing efficiency of copper material. During the electrochemical polishing process, both the components and operation parameters of electrochemical polish solution are the key factors influencing planarization ability. This work measured the surface topography and roughness of copper material after mechanical polish by an atomic force microscope (AFM), and added glycerol in different ratios to the phosphoric acid (85 wt %), which was the main composition of experiment solution. Electrochemical polish was conducted within the potential action range in passivation area, and the surface topography and roughness of copper material after electrochemical polish was measured by AFM. The difference in surface topography of copper material after electrochemical polish was compared as well.The experiment indicated that after electrochemical polish in pure phosphoric acid for 50 sec, the surface roughness of copper material obviously decreased from 6.921nm (Ra) to 0.820nm (Ra), and the planarization was more obvious with the increase of electrochemical polish time. The above results could appear in different electrolyte formulas, indicating that electrochemical polish was a good processing method for copper material planarization. This work also proposed the effect of analyzing the electrochemical polish time on planarization through planarization efficiency. Based on the analysis, the planarization efficiency was decreased with the increase of electrochemical polish time, which indicated that longer electrochemical polish time did not yield better result. This work also found that the surface is not only flattened, but also glossed after electrochemical polish.