Organized nanostructures are formed after irradiation of layers of randomly aligned single-wall carbon nanotube (SWNT)-polymer composites by a Ti:Sapphire 775 nm laser with a 150 fs pulse at fluences near 0.1 J/cm2. A...
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Organized nanostructures are formed after irradiation of layers of randomly aligned single-wall carbon nanotube (SWNT)-polymer composites by a Ti:Sapphire 775 nm laser with a 150 fs pulse at fluences near 0.1 J/cm2. At varying peak fluences morphology is seen where the tubes are ejected from the substrate or formed into long, parallel structures of SWNT’s. These structures have been created on both glass substrates and carbon grids. Transmission Electron Microscopy (TEM) and Scanning Electron Microscopy (SEM) investigation of the structures reveal that they are composed of bundled nanotubes typically 400 nm – 1 micron long. Large-area laser patterning of the film allows for structuring of the film without detrimental decreases in conductivity.
Exchange bias (EB) is usually observed in systems with an interface between different magnetic phases after field cooling. Here we report an unusual phenomenon in which a large EB can be observed in Ni-Mn-In bulk allo...
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Exchange bias (EB) is usually observed in systems with an interface between different magnetic phases after field cooling. Here we report an unusual phenomenon in which a large EB can be observed in Ni-Mn-In bulk alloys after zero-field cooling from an unmagnetized state. We propose that this is related to the newly formed interface between different magnetic phases during the initial magnetization process. The magnetic unidirectional anisotropy, which is the origin of the EB effect, can be created isothermally below the blocking temperature.
We develop a collisional-radiative model for calculating the velocity distributions of excited hydrogen atoms. In the model, the velocity distributions are approximated using linear combinations of several basis funct...
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Writing with ink involves the supply of liquid from a pen onto a porous hydrophilic solid surface, paper. The resulting linewidth depends on the pen speed and the physicochemical properties of the ink and paper. Here ...
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Writing with ink involves the supply of liquid from a pen onto a porous hydrophilic solid surface, paper. The resulting linewidth depends on the pen speed and the physicochemical properties of the ink and paper. Here we quantify the dynamics of this process using a combination of experiment and theory. Our experiments are carried out using a minimal pen, a long narrow tube that serves as a reservoir of liquid, which can write on a model of paper, a hydrophilic micropillar array. A minimal theory for the rate of wicking or spreading of the liquid is given by balancing the capillary force that drives the liquid flow and the resistance associated with flow through the porous substrate. This allows us to predict the shape of the front and the width of the line laid out by the pen, with results that are corroborated by our experiments.
The structural, magnetic, and electronic structural properties of Ni 0.2Cd0.3Fe2.5-xAlxO4 errite nanoparticles were studied via X-ray diffraction (XRD), transmission electron microscopy (TEM), DC magnetization, and ne...
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In this paper, shear deformation at high strain rates is modeled within the framework of discrete dislocation plasticity. The method of discrete dislocation plasticity is extended to incorporate the temperature rise i...
In this paper, shear deformation at high strain rates is modeled within the framework of discrete dislocation plasticity. The method of discrete dislocation plasticity is extended to incorporate the temperature rise induced by moving dislocations. Also, the stress and displacement fields of a screw dislocation on inclined planes in a periodic structure are developed. The influence on the temperature rise on various micro-mechanical processes is discussed.
Wire bonding is the most popular interconnection technique that has been used in microelectronics packaging due to its maturity and cost effectiveness. The technology advances in the era of miniaturization and multifu...
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Wire bonding is the most popular interconnection technique that has been used in microelectronics packaging due to its maturity and cost effectiveness. The technology advances in the era of miniaturization and multifunction have urges the need for the smaller wire bond size to cope with the decrease of bond pad pitches. Ultimately, this will introduces al lot of technology challenges in the characterization and performance of wire bonding micromechanical properties.
Silicon carbide is a very attractive material for a variety of applications. Originally considered for use in high power and high temperature electronics because of its large bandgap, designers of MEMS are now conside...
Silicon carbide is a very attractive material for a variety of applications. Originally considered for use in high power and high temperature electronics because of its large bandgap, designers of MEMS are now considering use of silicon carbide because of its stability at high temperatures, resistance to corrosives, high stiffness, and radiation resistance. However, as with any new structural material, its mechanical properties must be measured for design information. This research measures the elastic modulus, strength, and Poisson's ratio of two different silicon carbides using microtensile testing. One material is a 0.5-1νm thick film from Case Western Reserve University. Preliminary results give an average of 420 GPa for elastic modulus, a strength of 1.2 GPa, and a Poisson's ratio of 0.19. The second material is from Massachusetts Institute of Technology with an average thickness of 30 microns. Preliminary results show an elastic modulus of 430 GPa, a strength of 0.49 GPa, and a Poisson's ratio of 0.24. In addition to the most recent results, techniques used to obtain these results, microstructure investigations, and a comparison of the materials are detailed.
In this paper, we review various LTPS backplane technologies based on laser-crystallization and other related methods that have been applied to AMLCD and AMOLED displays. The TFT performances obtained by different mel...
In this paper, we review various LTPS backplane technologies based on laser-crystallization and other related methods that have been applied to AMLCD and AMOLED displays. The TFT performances obtained by different melt-mediated crystallization methods with excimer laser and solid phase crystallization will be compared. The technical issues of the image quality and the resolution will be discussed.
Previously we modeled the undulatory subsurface locomotion of the sandfish lizard with a sand-swimming robot which displayed performance comparable to the organism. In this work we control the lift forces on the robot...
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Previously we modeled the undulatory subsurface locomotion of the sandfish lizard with a sand-swimming robot which displayed performance comparable to the organism. In this work we control the lift forces on the robot by varying its head shape and demonstrate that these granular forces predict the vertical motion of the robot. Inspired by the tapered head of the sandfish lizard, we drag a wedge shaped object horizontally and parallel to its lower face through a granular medium and show that by varying the angle of the upper leading surface of the wedge, α, the lift force can be varied from positive to negative. Testing the robot with these wedges as heads results in vertical motion in the same direction as the lift force in the drag experiments. As the robot moves forward, the force on its head normal to the body plane results in a net torque imbalance which pitches the robot causing it to rise or sink within the medium. Since repeatedly varying α for a wedge head to achieve a desired lift is impractical, we test robot heads that approximate a wedge head inclined at varying angles by changing the angle of the bottom and top surfaces of the wedge, and show that similar lift control is achieved. Our results provide principles for the construction of robots that will be able to follow arbitrary trajectories within complex substrates like sand, and also lend support to hypotheses that morphological adaptations of desert-dwelling organisms aid in their subsurface locomotion.
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