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Electrostatic forces can be used to control the motion of charged particles. In this article, particle charging and motion in an electric field under ultraviolet (UV) irradiation were investigated. When the particle layers deposited on an insulating substrate were irradiated with UV light in a downward electric field, photoelectrons were emitted, and positive charges moved to the bottom of the particle layers. Subsequently, by reversing the direction of the electric field, the positive charges in the bottom moved upward; thus, the particles in the top layer were positively charged and levitated by Coulomb forces. The flux of the levitated particles increased with an increase in the strength of the electric field (downward and upward). As the upward electric field strength increased, the number of agglomerated particles in the levitation increased; however, the particle charge decreased. As the thickness of the particle layers increased, the time delay for particle levitation increased; however, the flux of the levitated particles decreased. The ratio of agglomerated particles to the total levitated particles increased. These results can be explained by the mechanisms of charge transfer and particle levitation. [ABSTRACT FROM AUTHOR]

The charging and levitation of particles using UV irradiation in an upward electric field were investigated. Glass beads with a mass median diameter of 61 μm were used for the experiments. The particle layers formed on a glass plate were irradiated by UV light with wavelengths ranging from 240 to 400 nm. The particles in the top layer were positively charged by photoemission and levitated by the electrostatic forces. The fluxes and motions of the levitated particles were analyzed by digital processing of the images obtained with a high-speed camera. The charge of each levitated particle was determined by fitting the results calculated using the equation of motion to the experimentally obtained particle motion. The charge of the particles beginning to be levitated was determined by the force balance and thus was not affected by the UV irradiance. The positive charge of the levitated particles could be increased by continuous photoemission from the particles and decreased by the capture of photoelectrons emitted by other particles. Approximately 40% of the levitated particles descended because of the negative charge clouds formed by the photoemission from the particle layers and the levitated particles. Furthermore, in a second set of experiments, an upward electric field was applied after UV irradiation. In these experiments, the particles in the top layer were levitated after applying the electric field. These particles could be gain more excess charges than the particles for which the levitation was governed by the force balance. [ABSTRACT FROM AUTHOR]

The corrosion of ceramic chamber parts causes particles in plasma etching process, so that the production yield and the overall equipment effectiveness (OEE) at LSI mass production line are decreased. We have developed magnesium oxide (MgO)-based ceramics whose corrosion resistance in reactive plasma is higher than conventional ceramic materials. In this study, we have prepared a shower-head-type electrode by using MgO-based ceramics, and demonstrated that the number of particles generated from the electrode is much lower than that generated from a conventional electrode made from aluminium oxide. The MgO-based ceramics contributes to improvement of the production yield and the OEE. [ABSTRACT FROM AUTHOR]

In modern semiconductor manufacturing, one type of measured particle count data contains excess zeros, and the ratio of zeros in the measurements is usually larger than 50%. This type of particle count sample data cannot be well modeled by popular defect models such as Poisson, zero-inflated Poisson, generalized zero-inflated Poisson, and Neyman and Gamma-Poisson models. In this paper, a threshold-Poisson model was proposed to describe the particles with excess zero counts, and the method for parameter estimation was developed. Via comparison with those popular models by using 15 measured samples, it showed that the measurements are better modeled by the threshold-Poisson model. A control chart called threshold-c control chart was proposed and the control limits were derived. A reasonable minimum sample size for constructing control chart was also discussed based on simulations. [ABSTRACT FROM AUTHOR]

This paper presents the numerical analysis and experiments on the electromechanical behavior of conducting wired-shape particles. We investigate the effects of particle ending profiles and orientation on the initial motion. The boundary element method is used to analyze the electric field, forces, and torques on the particles. The calculated liftoff electric field is smaller than the estimated value based on a model of infinitely long cylinder, and slightly decreases for a particle with a sharp end when the sharp tip is separated from the electrode. The measured liftoff electric field agrees with the tendency obtained from the numerical analysis. Particles mostly began the motion at either end. When the sharp tip was separated from the electrode, the initial motion almost exclusively took place at the sharp end. On the other hand, the probability was slightly higher for the motion at the rounded end when the sharp tip was close to the electrode. The numerical calculation clarifies that the electrostatic and gravitational torques contribute to such liftoff behavior. [ABSTRACT FROM AUTHOR]

Aerosol deposition (AD) method is technique for forming high density ceramic films on substrate material surface at room temperature. The yttrium oxide films formed by the AD method (AD-Y2O3 films) have been developed as plasma resistance coating used for the plasma etching equipment. In recent years, plasma eroded particles from chamber components of the etching devices are regarded as a serious issue that they reduce the semiconductor device yield rate. AD-Y2O3 films which have excellent plasma resistance can reduce the eroded particles in the plasma etching equipment and greatly have contributed to manufacturing high integrated semiconductor devices. In this paper, the plasma erosion behavior of AD-Y2O3 films were investigated compared with sintered Al2O3, sintered Y2O3 and thermal splayed Y2O3 in order to clarify the reason why AD Y2O3 films were superior as plasma resistance material. The plasma etching rates of AD-Y2O3 films were not significantly different from other samples. It was assumed that the etching rates were dependent on the chemical stability to fluorine plasma of material. On the other hand, the surface roughness difference before and after plasma exposure of AD-Y2O3 films were much smaller than other samples. It was assumed that the surface roughness difference is dependent on the crystalline size of material. The structure of AD-Y2O3 films, which had high density and nano-crystalline structure, were eroded homogeneously and smoothly. It suggests AD-Y2O3 films do not generate large eroded particles and are superior to reduce the eroded particles in the etching devices. [ABSTRACT FROM AUTHOR]

Considering an actual collection of spherical particles dispersing in a medium, we study in detail the polarization of particles and the effective static dielectric constant by two general models. Particles embedded in a medium lead to core-shell structure. The shell is the interface layer between the particle and the medium. With the effect of the interface layer included, these models are exactly solved with some details for metallic particles and non-metallic particles, respectively. The effective static permittivity of the composite material is approximated by Maxwell-Garnett method. The significant change of the effective permittivity is given by a term in proportional to the volume ratio of the interface layer, which is big for nano-sized particles. The permittivity of the interface layer plays an important role in the dependence of the effective permittivity of the composite material on particle size. [ABSTRACT FROM PUBLISHER]

The deactivation of free particles is an important issue for improving the insulating capability and reliability of high-voltage systems. In this work, we carry out experiments to investigate the electromechanical behavior of the non-spherical conducting particles for different particle orientations on either bare or coated electrode. Spheroidal and wire-shaped particles are used for the experiments. The particle motion is observed for two principal orientations with respect to the applied electric field in air. The results show that on a bare electrode, both kinds of particles exhibit the liftoff motion when the particle axis is aligned with electric field gradient. The field nonuniformity enhances the upward rotation of the particle tip subjected to the higher electric field. When the particle axis is parallel with a constant field line, the wire-shaped particle is more readily to make a rolling motion to the region of stronger electric field in comparison with the spheroidal particle, which shows higher occurrence rate of liftoff. The motion onset electric field decreases with increasing field nonuniformity. On the insulated electrode, the wire-shaped particle shows exclusively the rolling motion, whereas the spheroidal particle may make a rolling motion or rotate horizontally so as to align its axis with electric field gradient. [ABSTRACT FROM PUBLISHER]

The frequent forest fires become a serious threat to the performance of transmission lines' external insulation. Gap breakdown in forest fire relates to many factors, such as flame temperature, conductivity and particles. Large quantities of smoke (carbon black) and flying ash are produced during the combustion of vegetation, causing the dielectric strength of gap to decrease drastically. In order to analyze the influence of forest fire particles on the breakdown characteristics of air gap, the experimental setup consisting of a conductor-plane was built to simulate the effect of forest fire particles. At the same time, a theoretical model was developed to analyze the influence mechanism of multiple particles on the discharge characteristics of gap. Experimental results show that, a chain of carbon particles has been formed between flame and conductor by the action of electric field. The gap's insulation strength decreases significantly, which is about 40% of that in the pure air under AC voltage. The particles movement and the breakdown characteristics of air gap have an evident effect of polarity characteristic under DC voltage and the breakdown voltage is reduced to about 29% of that in the air gap under negative DC voltage. The simulation results show that, the electric field distribution between conductor and plane become uneven, and the distortion degree of the elongated particle to the background electric field is not related to the distance between particles with high-voltage electrode. According to the electric field diagram, it is obvious that the particles make the background electric field distortion, and the maximum field strength increased by about 100%. More close to the conductor, the greater electric field strength is at the both ends of particles. [ABSTRACT FROM AUTHOR]

Microelectromechanical systems (MEMS) that require contact of moving parts to implement complex functions exhibit limits to their performance and reliability. Here, we advance our particle tracking method to measure MEMS motionin operandoat nanometer, microradian, and millisecond scales. We test a torsional ratcheting actuator and observe dynamic behavior ranging from nearly perfect repeatability, to transient feedback and stiction, to terminal failure. This new measurement capability will help to understand and improve MEMS motion. [2018-0118] [ABSTRACT FROM AUTHOR]

An overview of cyclotron development in research laboratories worldwide and the impressive growth of commercial cyclotrons during the last 50 years are summarized. The role of the superconducting cyclotrons, the return of the synchrocyclotrons, the flourishing interest in the fixed field alternating gradient (FFAG), and finally the proposed design for 10-MW class cyclotrons are also presented. [ABSTRACT FROM PUBLISHER]

This paper presents a numerical method to simulate the particle trajectory in the head–disk interface (HDI). The simulator solves the reduced Navier–Stokes equation with the second-slip boundary conditions to get the air velocity distribution, then solves the motion equations of particles and obtains the trajectories of the particles in the HDI using the binary Lagrange interpolation and the fourth-order Runge–Kutta method. The calculated trajectories of particles follow well with the air streamlines in the recessed regions. The particle density, diameter, and initial entering velocity have different effects on particle movement. Furthermore, particle velocity behaviors in the recessed regions are investigated for the first time. The particle is accelerated or decelerated by the action of the drag force and becomes close to the velocity of local air flow. Such effects are more obvious for small particles than large particles. The particle velocity becomes very small when it is close to the leading edge of the trailing pad. The numerical results also show that the particle goes up when it crosses the transition regions, and the particle moves upward more sharply with higher initial entrance height due to the larger vertical velocity of the local air flow. [ABSTRACT FROM AUTHOR]

Particle filters provide a general framework for dynamic state estimation (DSE) in nonlinear systems. The scope for particle filter-based DSE can be significantly enhanced by exploiting data from phasor measurement units (PMUs) when available at higher sampling frequencies. In this paper, we present a particle filtering approach to dynamically estimate the states of a synchronous generator in a multi-machine setting considering the excitation and prime mover control systems. The filter relies on typical output measurements assumed available from PMUs stationed at generator buses. The performance of the proposed filter is illustrated with dynamic simulations on IEEE 14-bus system including: 1) generators models with subtransient dynamics, 2) excitation units (IEEE DC1A, DC2A, AC5A), and 3) turbine-governor models (steam and hydro). The estimation accuracy of the proposed filter is assessed for three classes of disturbances assuming noisy PMUs' measurements and comparative results are presented with the unscented Kalman filter (UKF). The accuracy-computational burden trade-off is also analyzed and the results strengthen the feasibility of using particle filters for dynamic state estimation. [ABSTRACT FROM PUBLISHER]

In this paper, an algorithm is presented for estimating scene flow, which is a richer, 3D analog of optical flow. The approach operates orders of magnitude faster than alternative techniques and is well suited to further performance gains through parallelized implementation. The algorithm employs multiple hypotheses to deal with motion ambiguities, rather than the traditional smoothness constraints, removing oversmoothing errors and providing significant performance improvements on benchmark data, over the previous state of the art. The approach is flexible and capable of operating with any combination of appearance and/or depth sensors, in any setup, simultaneously estimating the structure and motion if necessary. Additionally, the algorithm propagates information over time to resolve ambiguities, rather than performing an isolated estimation at each frame, as in contemporary approaches. Approaches to smoothing the motion field without sacrificing the benefits of multiple hypotheses are explored, and a probabilistic approach to occlusion estimation is demonstrated, leading to 10 and 15 percent improved performance, respectively. Finally, a data-driven tracking approach is described, and used to estimate the 3D trajectories of hands during sign language, without the need to model complex appearance variations at each viewpoint. [ABSTRACT FROM AUTHOR]

This paper describes the design, the fabrication, and the characterization of an interdigitated 3-D silicon (Si) ring microelectrodes for dielectrophoretic (DEP) manipulation of particles. The 3-D microelectrodes are derived from a high-aspect-ratio comb structure etched in a doped single crystal Si on an insulating dielectric (silicon-on-insulator). Fingers of the comb are evolved into ring microelectrodes once perforated with a linear array of well-defined round lateral constrictions. This is achieved by the segmented finger layout and the Si dry release strategy borrowed from inertial microelectromechanical systems. The fingers and their interspaces are sealed with a cover layer forming a microfluidic flow chamber surrounded by 3-D microelectrodes and accessible via single inlet/outlet. The functionality of the device has been verified on 2- and 10-\mu \m polystyrene microspheres in pressure-driven flow through the ring microelectrodes at 3.3 \mu\L/min effectively focusing them into streams or trapping them around the fingers at moderate voltage levels (20–40 Vpp). \hfill[2012-0209] [ABSTRACT FROM PUBLISHER]

This paper proposes a new semitransparency-based optical-flow model with a point trajectory (PT) model for particle-like video. Previous optical-flow models have used ranging from image brightness constancy to image brightness change models as constraints. However, two important issues remain unsolved. The first is how to track/match a semitransparent object with a very large displacement between frames. Such moving objects with different shapes and sizes in an outdoor scene move against a complicated background. Second, due to semitransparency, the image intensity between frames can also violate a previous image brightness-based optical-flow model. Thus, we propose a two-step optimization for the optical-flow estimation model for a moving semitransparent object, i.e., particle. In the first step, a rough optical flow between particles is estimated by a new alpha constancy constraint that is based on an image generation model of semitransparency. In the second step, the optical flow of a particle with a continuous trajectory in a definite temporal interval based on a PT model can be refined. Many experiments using various falling-snow and foggy scenes with multiple moving vehicles show the significant improvement of the optical flow compared with a previous optical-flow model. [ABSTRACT FROM PUBLISHER]

We compare the chip separation techniques for InGaN-based light emitting diode (LED), which are prepared by conventional diamond tip scribing and short pulse laser scribing with pulse width of nanosecond or femtosecond. Differently from the diamond tip scribing, the laser scribing does not suffer from the shallow scribing depth, which usually results in a failure in cleaving the wafer along the scribed line. Furthermore, the LED scribed by using a femtosecond pulse laser exhibits an 11% enhancement in the output power at 20 mA, compared to that by using a nanosecond pulse laser. This is because the femtosecond laser scribing not only eliminates particle generation, but also minimizes the effect of thermal damage on the sapphire substrate. The femtosecond laser also offers a high speed, high yield, and hence low cost scribing process due to its extremely short pulse width and deep focal length. [ABSTRACT FROM AUTHOR]

Particle trap wafers were applied to ArF immersion lithography to reduce the immersion-related defectivity. Interfacial free energy (γA-particIe) and work of adhesion (WA-particle) between particle trap wafers and particles in immersion water explain the potential of trapping particles by the particle trap wafers. It was found that the treated SiCN chemical vapor deposition wafer performed well as a particle trap wafer and can help defect reduction in immersion lithography. [ABSTRACT FROM AUTHOR]

Submicron-size amorphous particles were produced chemically from aqueous solutions. The particles in the as-made state exhibit a high saturation magnetization and magnetic softness almost equivalent to that of much larger amorphous particles produced by water atmizing. Platinum ions work effectively to control the particle size without losing magnetic softness. Magnetic softness observed for the as-made particles becomes degraded slightly by annealing. A calculation of eddy current within spheres predicts no eddy current loss even at 100 MHz for 0.3-μm particles, whereas initial permeability measurements exhibit slight indication of magnetic loss due to the broad spin resonance profile extending from 100 MHz to 10 GHz. [ABSTRACT FROM AUTHOR]

The phenomenon of accumulated charges on solid insulator surfaces is one of the critical parameters to consider at the insulation design stage, for ac electric power equipment as well as for dc equipment, so it is important to investigate the characteristics and predominant factors underlying various charging mechanisms. Several researches related to this theme have been reported, but independently, and cross-sectional comparison and evaluation from a unified viewpoint are meaningful. In this paper, the resistance of solid insulator is first discussed, showing that the resistances found by diverse measurements are in a fairly good agreement under similar conditions of the temperature and electric field. Next, three kinds of electric charging mechanisms, i.e. volume conduction, surface conduction and electric field emission are characterized in terms of the time constant, applied voltage and charge distribution. Then, eight cases of recent measurements on the charging time are investigated and their charging mechanisms are classified. Electric field emissions are likely to occur with model spacers made in routine GIS manufacturing process at the electric field level used. Further, three examples in cases with metallic particles are introduced, of simulating charge from edge on the tank, spacer surface charging phenomena, and influence of charge on spacer surface flashover. It is expected that this paper will be helpful for understanding charging phenomena e.g. on insulation spacers in gas insulated switchgears. [ABSTRACT FROM AUTHOR]

This paper deals with the breakdown voltage characteristics of saturated liquid helium in the presence of a needle-shaped or spherical metallic particle to obtain insulation design data for pool-cooled, low-temperature superconducting coils and to find the predominant factor affecting the breakdown voltage of liquid helium at a given state. The results show the following. (1) The generation of bubbles at the instant of collision of a particle with an electrode is caused mainly by the kinetic energy released from the moving particle to the liquid helium, while the electrostatic energy accompanying the microdischarge between the particle and the electrode has a lesser effect on it. (2) The lowest breakdown voltage at different particle conditions appears in the case of a free needle particle. The low breakdown voltage is caused by the bubble triggered by the particle collision, the high electric field at the tip of the needle particle, and the rich initial electrons supplied by the microdischarge. [ABSTRACT FROM AUTHOR]

It is well known that particles can be freely levitated in an electric field due to the charge induced on the particles by the external field. The charge depends upon the electric field strength and particle properties. This paper studies some of these factors to investigate the fundamentals of induction charging for granular materials. An experimental apparatus was set up to collect the levitated particles in a filter contained in a Faraday pail and the charge-to-mass (Q/M) ratio was obtained based on the charge and mass measurements for the samples in the filter. Furthermore, the particle size distribution was measured and analyzed by laser diffraction and microscopy and the surface mean diameter (Ds) and volume mean diameter (Dv) were obtained. In these experiments irregular shaped Al2 O3 particles and spherical glass beads with a size range of 42-390 μm were used and tested at different electric field strengths. By combining the results of Q/M, Ds and Dv, the charge per particle was calculated and the results compared with theoretical values. It was confirmed that the particle charge is dependent upon the electric field strength and the particle properties of size, shape, density, resistivity, and adhesive force. [ABSTRACT FROM AUTHOR]

A hard particle interacting with a slider and a disk in the head/disk interface of hard-disk drives can produce a scratch on the disk and result in data loss. Our work emphasizes modeling and simulation of slider, particle, and disk interactions, scratch generating mechanisms, and linking of scratch to interface design parameters. Two models are presented. The Monte Carlo method was used to calculate scratch probabilities and parametric studies were performed to determine the effect on scratch probability of various parameters, such as friction coefficients, particle mean size, slider wall angles, the ion-milling (IM) etch depth from the air-bearing surface (ABS) of the slider, and the efficacy of additional ABS structures acting as particle shields. Simulation results show that the friction coefficient is a dominant parameter. If the disk friction coefficient is smaller than the slider friction coefficient, scratches are not produced. Using shallow IM depths is an effective and practical way to reduce the scratch probability. Experimental results are very close to the simulation predictions. [ABSTRACT FROM AUTHOR]

The force acting upon a free metallic particle in an alternating electric field will determine its motion and ultimately allow for the estimation of the risk imposed due to dielectric failure of the high voltage equipment. Existing models approximate the force with Lorentz' law and consider the charge resting upon the surface as being lumped into a point charge at the center of the particle during its motion. The model proposed in this paper demonstrates a time stepped electrostatic Finite Element Method to calculate these forces, therefore taking into account the charge distribution upon the surface of the particle. The use of this model is seen to have a significant effect upon the motion of the particle under certain conditions. [ABSTRACT FROM AUTHOR]