Electrostatic Capacity Research Articles

電気二重層キャパシタの等価回路モデルに関する一考察

Various models for the equivalent circuit of EDLC (Electric Double Layer Capacitor) have been presented so far. The multi-stage connection of RC circuit is a representative model to simulate the EDLC's charge-discharge characteristic. However, since high energy density type EDLC for electric power storage has the electrostatic capacity of thousands F, the phenomenon of being almost uninfluential for the case of conventional capacitor appears in an actual measurement notably. To overcome this difficulty, we develop an equivalent circuit model using a nonlinear model that considers the voltage dependency of the electrostatic capacity in this paper. After various simulations and comparison with experimental results, we confirmed the effectiveness of the proposed model.

Practical Active Auxiliary Resonant DC Link Snubber with A Single Diode Clamping Loop for Suppressing Its ZCS Related Switch Parasitic High Frequency Oscillation

A practical active auxiliary quasi-resonant dc link snubber circuit with a diode clamping loop to reduce the switching losses and suppress a voltage ringing which causes in the loop including auxiliary zero current switching device; IGBT with parasitic electrostatic capacity is evaluated experimentally.

Intrinsic viscosity and the electrical polarizability of arbitrarily shaped objects.

The problem of calculating the electric polarizability tensor alpha(e) of objects of arbitrary shape has been reformulated in terms of path integration and implemented computationally. The method simultaneously yields the electrostatic capacity C and the equilibrium charge density. These functionals of particle shape are important in many materials science applications, including the conductivity and viscosity of filled materials and suspensions. The method has been validated through comparison with exact results (for the sphere, the circular disk, touching spheres, and tori), it has been found that 10(6) trajectories yield an accuracy of about four and three significant figures for C and alpha(e), respectively. The method is fast: For simple objects, 10(6) trajectories require about 1 min on a PC. It is also versatile: Switching from one object to another is easy. Predictions have also been made for regular polygons, polyhedra, and right circular cylinders, since these shapes are important in applications and since numerical calculations of high stated accuracy are available. Finally, the path-integration method has been applied to estimate transport properties of both linear flexible polymers (random walk chains of spheres) and lattice model dendrimer molecules. This requires probing of an ensemble of objects. For linear chains, the distribution function of C and of the trace (alpha(e)), are found to be universal in a size coordinate reduced by the chain radius of gyration. For dendrimers, these distribution functions become increasingly sharp with generation number. It has been found that C and alpha(e) provide important information about the distribution of molecular size and shape and that they are important for estimating the Stokes friction and intrinsic viscosity of macromolecules.

Occupant position detection system (OPDS) for side airbag system

In order to prevent injury of the occupant of the passenger seat when a side airbag deploys, we have developed an occupant position detection system. It detects the occupant's head entering the side airbag deployment zone. If so, the side airbag operation is inhibited and an indicator light on the side airbag alerts the occupant to the improper sitting position. It detects accurately the occupant's size and the head entering the side airbag deployment zone, using an occupant identification algorithm and electrostatic capacity sensors under the seat trim cover which determine the dielectric around the seat surface.

414 静電容量式翼端すきま測定法の研究(計測・制御・ロボット)

414 静電容量式翼端すきま測定法の研究(計測・制御・ロボット)

Colocalization of single ribosomes with intermediate filaments in puromycin-treated and serum-starved mouse embryo fibroblasts

Previous experiments have revealed a relatively weak electrostatic binding capacity of in vitro reconstituted intermediate filaments (IFs) as well as of natural IFs of whole cell mount preparations for purified ribosomal particles of mammalian origin. In order to demonstrate that such associations also occur in vivo, intact cells were subjected to double immunofluorescence microscopy using antibodies directed against vimentin and ribosomal protein S17. Since in proliferating cells the majority of the ribosomal particles are assembled into polyribosomes and these are to a great extent associated with microfilaments, in vitro cultured mouse embryo skin fibroblasts (MSF cells) were treated with puromycin to allow the formation of single ribosomes. Employing confocal laser scanning microscopy, the ribosomes were detected in colocalization with vimentin IFs. Disassembly of polyribosomes was also achieved by serum starvation of cultured cells. In this case, MSF cells of a low passage attained an extended and flattened appearance with the vimentin IFs being directly associated with the cell nuclei, radiating into the peripheral areas of the cells or showing a stress fiber-like distribution. In both cases, considerable quantities of ribosomal material were seen in close neighborhood to vimentin IFs. Frequently, these ribosome-IF associations were coaligned with microtubules and they also surrounded myosin I-decorated stress fibers. Double labeling with the vital, RNA-specific fluorochrome SYTO 14 produced a fluorescence pattern largely super-imposable on that of ribosomal protein S17. Treatment of the starved cells with either demecolcine or cytochalasin D had an only moderately disturbing effect on vimentin IF distribution and the ribosomes stayed in contact with the vimentin IFs. On the basis of these results, it is conceivable that IFs play a role in the storage of ribonucleoprotein particles in general and non-translating ribosomes in particular in the cytoplasm of animal cells. In addition, the often seen coalignment of IFs with microtubules and microfilaments might serve facilitated and directional transport of ribonucleoprotein particles from the nucleus to peripheral areas of the cell.

Colocalization of single ribosomes with intermediate filaments in puromycin-treated and serum-starved mouse embryo fibroblasts*

Previous experiments have revealed a relatively weak electrostatic binding capacity of in vitro reconstituted intermediate filaments (IFs) as well as of natural IFs of whole cell mount preparations for purified ribosomal particles of mammalian origin. In order to demonstrate that such associations also occur in vivo, intact cells were subjected to double immunofluorescence microscopy using antibodies directed against vimentin and ribosomal protein S17. Since in proliferating cells the majority of the ribosomal particles are assembled into polyribosomes and these are to a great extent associated with microfilaments, in vitro cultured mouse embryo skin fibroblasts (MSF cells) were treated with puromycin to allow the formation of single ribosomes. Employing confocal laser scanning microscopy, the ribosomes were detected in colocalization with vimentin IFs. Disassembly of polyribosomes was also achieved by serum starvation of cultured cells. In this case, MSF cells of a low passage attained an extended and flattened appearance with the vimentin IFs being directly associated with the cell nuclei, radiating into the peripheral areas of the cells or showing a stress fiber-like distribution. In both cases, considerable quantities of ribosomal material were seen in close neighborhood to vimentin IFs. Frequently, these ribosome-IF associations were coaligned with microtubules and they also surrounded myosin I-decorated stress fibers. Double labeling with the vital, RNA-specific fluorochrome SYTO 14 produced a fluorescence pattern largely superimposable on that of ribosomal protein S17. Treatment of the starved cells with either demecolcine or cytochalasin D had an only moderately disturbing effect on vimentin IF distribution and the ribosomes stayed in contact with the vimentin IFs. On the basis of these results, it is conceivable that IFs play a role in the storage of ribonucleoprotein particles in general and non-translating ribosomes in particular in the cytoplasm of animal cells. In addition, the often seen coalignment of IFs with microtubules and microfilaments might serve facilitated and directional transport of ribonucleoprotein particles from the nucleus to peripheral areas of the cell.

Some Overdetermined Boundary Value Problems with Elliptical Free Boundaries

In this paper we study three different overdetermined boundary value problems in R2: a problem of torsion, a problem of electrostatic capacity, and a problem of polarization. In each case we prove that a solution exists if and only if the free boundary is an ellipse. The techniques we use rely on classical complex function theory, maximum principle, and some topological argument.

Preparation of monodispersed polymeric microspheres for toner particles by the shirasu porous glass membrane emulsification technique

This investigation describes the experiment directed toward the production of monodispersed toner particles by suspension polymerization. That is, relatively monodispersed poly(styrene-co-divinylbenzene) microspheres containing electrifying additives were successfully prepared by suspension polymerization employing the Shirasu Porous Glass (SPG) membrane emulsification technique. The diameter distribution of the dispersed droplets prepared with an SPG membrane module was fairly narrow, compared with that prepared with a conventional mechanical homogenizer. The effect of Sumiplast Blue S as coloring matter and E-81 as charge control agent on the triboelectric discharging properties of prepared polymeric microspheres was studied. The addition of electrifying additives strongly affected the triboelectric discharging property. It was consequently clarified that a small amount of electrifying additives added raised the electrostatic capacity of polymeric microspheres. However, a further addition reduced the triboelectric discharge of polymeric microspheres. © 1997 John Wiley & Sons, Inc. J Appl Polym Sci 64: 1107–1113, 1997

Preparation of monodispersed polymeric microspheres for toner particles by the shirasu porous glass membrane emulsification technique

This investigation describes the experiment directed toward the production of monodispersed toner particles by suspension polymerization. That is, relatively monodispersed poly(styrene-co-divinylbenzene) microspheres containing electrifying additives were successfully prepared by suspension polymerization employing the Shirasu Porous Glass (SPG) membrane emulsification technique. The diameter distribution of the dispersed droplets prepared with an SPG membrane module was fairly narrow, compared with that prepared with a conventional mechanical homogenizer. The effect of Sumiplast Blue S as coloring matter and E-81 as charge control agent on the triboelectric discharging properties of prepared polymeric microspheres was studied. The addition of electrifying additives strongly affected the triboelectric discharging property. It was consequently clarified that a small amount of electrifying additives added raised the electrostatic capacity of polymeric microspheres. However, a further addition reduced the triboelectric discharge of polymeric microspheres. © 1997 John Wiley & Sons, Inc. J Appl Polym Sci 64: 1107–1113, 1997

埋め込みセラミックセンサの電気的特性によるコンクリートの含水率測定方法の提案

This paper proposes a non-destructive testing method of moisture content in hardened concrete by the electric prperties of a ceramic sensor embedded in concrete. In general, the clayburned porous ceramics has a superior water absorption and discharge capability, and it is electrical insulative in a drying state, but it is highly conductive and has electrostatic capacitance in a wetting state. The proposed method can utilize those characters to estimate moisture content in concrete. This paper deals with manufacturing method of the sensor, measuring conditions, influencing factors on the relationships between the moisture content and the electric resistance or electrostatic capacity and the measuring accuracy. The proposed method, however, requires the revision of electric resistance and electrostatic capacity by the ambient temperature, and the calibration curve by water content per unit volume of concrete. This paper, finally, illustrates the deviation of measured moisture content of the hardened concrete.

Study of protein binding to a silica support with a polymeric cation-exchange coating

A silica-based, polyacrylate ion-exchange stationary phase has been prepared using Ce(IV) as the initiator. Analysis of the physical properties of the polymeric layer separated from the silica surface indicates that the polymeric coating is cross linked to some extent. The polymerization carried out at different concentrations of Ce(IV) demonstrated that the effective surface area can be increased by lowering the Ce(IV) concentration at higher monomer concentrations of the reaction mixture. These materials are quite reproducible and of hifh electrostatic binding capacity; 1.485 μmol/m 2. The electrostatic binding capacity of a non-polymeric stationary phase reached the theoretical limit for a monolayer (0.16 μmol/m 2). However, the covalent binding capacity of the same stationary phase was only 50% of the electrostatic binding capacity. The same trend was observed in all the polymeric stationary phases tested. This shows that the mechanism of protein binding in polymeric and conventional stationary phases is similar, and multilayer electrostatic binding is highly unlikely in these sorbents examined. Z numbers revealed that the contact area of the protein is independent of the polymeric character of the stationary phase and therefore, the increased loading of these polymeric stationary phases is due to the increased surface area.

A minkowski problem for electrostatic capacity

A minkowski problem for electrostatic capacity

Geometrical percolation threshold of overlapping ellipsoids.

A recurrent problem in materials science is the prediction of the percolation threshold of suspensions and composites containing complex-shaped constituents. We consider an idealized material built up from freely overlapping objects randomly placed in a matrix, and numerically compute the geometrical percolation threshold ${\mathit{p}}_{\mathit{c}}$ where the objects first form a continuous phase. Ellipsoids of revolution, ranging from the extreme oblate limit of platelike particles to the extreme prolate limit of needlelike particles, are used to study the influence of object shape on the value of ${\mathit{p}}_{\mathit{c}}$. The reciprocal threshold 1/${\mathit{p}}_{\mathit{c}}$ (${\mathit{p}}_{\mathit{c}}$ equals the critical volume fraction occupied by the overlapping ellipsoids) is found to scale linearly with the ratio of the larger ellipsoid dimension to the smaller dimension in both the needle and plate limits. Ratios of the estimates of ${\mathit{p}}_{\mathit{c}}$ are taken with other important functionals of object shape (surface area, mean radius of curvature, radius of gyration, electrostatic capacity, excluded volume, and intrinsic conductivity) in an attempt to obtain a universal description of ${\mathit{p}}_{\mathit{c}}$. Unfortunately, none of the possibilities considered proves to be invariant over the entire shape range, so that ${\mathit{p}}_{\mathit{c}}$ appears to be a rather unique functional of object shape. It is conjectured, based on the numerical evidence, that 1/${\mathit{p}}_{\mathit{c}}$ is minimal for a sphere of all objects having a finite volume.

Electrostatic Characterization of Polymeric Microspheres Containing Electrifying Additives.

Polymeric microspheres showing unique triboelectricity properties have been exploited in the electric photograph. Despite that fact that a lot of factors have been reported to affect triboelectric properties, quantitative consideration of these factors has been left for future works.In this study, suspension polymerization was carried out to prepare polymeric microspheres of ca. 100 μm in diameter in which electrifying additives, such as carbon black (CB) and charge control agents (CCA), were well dispersed. The effects of additives on electrostatic capacities and physical properties of polymeric microspheres were investigated.It was found that the electrostatic capacity decreased with increasing CB content. The addition of CCA strongly affected the electrostatic capacities of polymeric microsphere. The effect of CCA on the electrostatic capacity is expected to be different for each CCA.

電位制御によるアルミニウム箔の交流エッチング特性

Aluminum foil of 99.99% purity was etched in an aqueous solution of 2mol dm-3 hydrochloric acid, 0.01mol dm-3 sulfuric acid, and 0.2mol dm-3 aluminum chloride at 303K by 5Hz AC wave with controlled anodic potential, Ea, and cathodic potential, Ec. The etched porous layer was evaluated by SEM observation, optical observation, electrostatic capacity measurement and CV behavior. Electrostatic capacity and porous structure were grcatly influenced by Ea and Eo values.To make etched pits, it was necessary to set potential Ea higher than the breakdown potential Ebd appearing in the CV curves. At Ea potentials only slightly higher than Ebd, the etched porous layer was thin and the thickness of the foil decreased at an anodic electric charge of 50C cm-2, while when Ea was too high, the pits showed local interconnection and the surface of the porous layer dissolved and lacked smoothness. The aluminum hydroxide film formed in the etched pits during the cathodic cycles played an important role in the characteristics of pit formation. The thickness of the aluminum hydroxide film increased at low Ec, when etching took place locally with several large pits on the foil. This might be caused by the non-uniformity of the hydroxide film on the bottoms of the pits. At high Ec, on the other hand, film protection was weak, leading to thinning of the porous layer and dissolution of the foil. In this study, the optimum etching conditions that provided high electrostatic capacity and a deep and uniform pit morphology were Ea=0.1V, Ec=-2.4V vs. SCE at an anodic charge C=50C cm-2

Electrostatic Properties of Poly(Styrene-co-Ddivinylbenzene) Microspheres with Different Surface Morphologies

The effect of surface morphology on electrostatic capacity was investigated using polymeric microspheres prepared with toluene, a toluene/n-dodecane mixture and n-dodecane as diluent. The results show that surface morphology can be changed by using diluents with different solubility parameters. The electrostatic capacity was, however, determined only by the void fraction of the microspheres, regardless of diluent. That is, it was found that the outer surface area able to contact with ferrite particles was the predominant factor in determining the triboelectric property of microspheres

長間隔平行平板空気コンデンサの静電容量に対するシールドとダミー電極の効果について

長間隔平行平板空気コンデンサの静電容量に対するシールドとダミー電極の効果について

Mechanism of misalignment failure of liquid-crystal display devices

Misalignment failure mechanisms which are a problem in twisted nematic liquid-crystal display devices were investigated. A life test which changes the driving conditions of the applied multiplexing voltage was implemented for devices which use estercy-clohexane liquid crystals. The life tests showed that misalignment life is longer with a lower voltage, a smaller duty ratio, and a higher frequency. These results are highly appropriate for models with alternating current electrolysis of the liquid-crystal material. In addition, electrostatic capacity and applied voltage properties were used to study the relationship of liquid-crystal dielectric anisotropy and the coupling coefficient with temporal misalignment changes. The coupling coefficient decreases along with misalignment failure.< <ETX xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">&gt;</ETX>

Investigation of GPT phase angle for tan .DELTA. measuring method of hot-line power cable.

As a diagnostic apparatus of deterioration of 6kV class XLPE cable on the hot line, a practical apparatus has been developed, which detects the voltage signal from a potential divider contacted with a high voltage live part and the charging current from a grounding conductor current and displays tan δ and electrostatic capacity. The authors have investigated the various methods, which are adopted to the state of cable line, in order to find the most important input procedure of the voltage signal for the application of this apparatus in the work site operation. We have proposed a method of using the secondary voltage of the GPT (ground potential transformer), which are installed especially at the many places such as substations and the like, and have developed and proved the method. We can expect that it can be applied not only for the 6kV class XLPE cable but also in the broad areas such as the continuous monitoring system for the cable and electrical equipments because it has outstanding properties especially in safety, operability and so on.The following items are discussed in this paper:(1) development of the new method/program, which can calculate the phase difference (phase angle) between the primary and secondary voltage signals of GPT, (2) method/equipment for measuring the burden of GPT, which is required for calculation of the phase angle, and the measuring results, and (3) the proven results in the field.