The method includes the steps of forming a porous insulation film and wires on the substrate, the wires embedded in the porous insulation film having a portion adjacent to the wires and a remote portion spaced apart from the wires; and applying an energy beam to the remote portion to change the structure of the porous insulation film such that an Young's modulus of the porous insulation film increased so as to substantially reinforce the strength of the porous insulation film.

1. Field of the Invention
The present invention relates to semiconductor devices and methods for fabricating the same. More particularly, the invention relates to a semiconductor device which has high mechanical strength despite the use of a material having a low relative dielectric constant for forming insulation films.
2. Description of the Related Art
With recent higher integration of semiconductor devices, wiring width and wiring pitch have been reduced markedly. Since the parasitic capacitance between wires is inversely proportional to the distance between adjacent wires (wiring pitch), a reduction in wiring pitch results in an increase in the parasitic capacitance between wires. The increase in the parasitic capacitance leads to a delay in signal propagation in the wires, which is an inhibiting factor in improving the operating speed of semiconductor devices.
In order to overcome such an "increase in the parasitic capacitance between wires", it is effective to decrease the relative dielectric constant of interlayer insulation films. That is, by using, as the material for interlayer insulation films, a material having a lower relative dielectric constant than materials commonly used, the parasitic capacitance between wires is decreased.
A porous insulation film has been noted as an insulation film having a very low relative dielectric constant. The porous insulation film is a film having many pores therein. If the "porous insulation film" is used as a material for an interlayer insulation film, the parasitic capacitance between wires can be decreased. However, under the influence of many pores present in the film, the mechanical strength of the film is decreased. As a result, it becomes difficult to provide a sufficient mechanical strength required for the device.
Under these circumstances, it has been proposed that a porous insulation film is selectively used in an interlayer insulation film. That is, in an interlayer insulation film, a porous insulation film is used only in an area that does not require strength (refer to Japanese Unexamined Patent Application Publication No. 2003-100757 [Patent Document 1] and Japanese Unexamined Patent Application Publication No. 2004-179386 [Patent Document 2]). Patent Document 1 discloses that a non-porous insulation film is provided in bonding pad forming regions so that the insulation film is not fractured during bonding, and a porous insulation film is provided in regions other than the bonding pad forming regions. Patent Document 2 discloses an example in which an interlayer insulation film having a low dielectric constant and being made of a porous material is provided only in narrow regions between wires, and a usual interlayer insulation film made of silicon dioxide (SiO2) is provided in regions other than the narrow regions.
However, in each of the techniques disclosed in Patent Documents 1 and 2, when an interlayer insulating film is formed, separate steps of forming two films made of different insulating materials (i.e., a porous insulating material and a non-porous insulating material) are required. Thus, the number of steps required for forming the interlayer insulating film is increased.

Semiconductor device having a interlayer insulation film with low dielectric constant and high mechanical strength


A radiation image-pickup device includes: a drive substrate including a transistor used to read, from each of a plurality of pixels, signal charge based on radiation; a charge collection electrode provided on the drive substrate, for each of the pixels; a conversion layer formed on the charge collection electrode, and configured to generate the signal charge by absorbing radiation; a counter electrode provided on the conversion layer; and a first conductive film disposed, between the drive substrate and the charge collection electrode, to face at least a part of the charge collection electrode, and included in a first capacitive element configured to retain the signal charge.

The present disclosure relates to a radiation image-pickup device obtaining an image based on radiation that has entered, and a radiation image-pickup display system including such a radiation image-pickup device.
In recent years, radiation image-pickup devices that obtain an image based on radiation such as X-rays as an electric signal have been developed (for example, Japanese Unexamined Patent Application Publication No. 2002-228757). Such radiation image-pickup devices are broadly divided into, so-called, an indirect conversion type and a direct conversion type. Of these, in the radiation image-pickup devices of the indirect conversion type, for example, a conversion layer generating electric signals by absorbing X-rays may be provided, and signal charge may be extracted from this conversion layer through a pair of electrodes.

Radiation image-pickup device and radiation image-pickup display system

Sony Semiconductor Solutions Corporation


The present invention relates to semi-aqueous compositions and the method using same, to remove highly cross-linked resists and etch-residues. The compositions are comprised of aminobenzenesulfonic acid, water miscible organic solvent and water.

In the manufacture of semiconductors or semiconductor microcircuits it is necessary to remove materials from the surface of the substrate of the semiconductor device. In some instances the materials to be removed are polymeric compositions referred to as photoresists. In other instances the materials to be removed are residues of etching or ashing processes or simply contaminants. The purpose of stripping and/or cleaning compositions is to remove unwanted materials from a semiconductor substrate without corroding, dissolving or dulling the exposed surface of the substrate.
The art contains numerous references to compositions of different types for use in stripping photoresist and/or cleaning etch residue, ash or other contaminants from semiconductor substrates.
Patents in this technological field include U.S. Pat. No. 5,972,862 to Torii, U.S. Pat. No. 6,232,283 B 1 to Inoue, U.S. Pat. No. 5,534,177 to Mayhan, U.S. Pat. No. 4,321,166 to McGrady, U.S. Pat. No. 4,199,483 to Jones, U.S. Pat. No. 3,653,931 to Borchert, U.S. Pat. No. 4,215,005, U.S. Pat. No. 4,165,295 and U.S. Pat. No. 4,242,218 to Mey.

Semi-aqueous stripping and cleaning composition containing aminobenzenesulfonic acid


A water-purifying apparatus, for reducing the radon content of radon-contaminated water, includes a reactor tank for treating the radon-contaminated water, a radon-releasing structure arranged in the upper part of the reactor tank to receive water from a first pump adapted to supply water from a source of water containing radon-contaminated water, the water from the radon-releasing structure accumulating in the reactor tank, an inlet duct extending between the first pump and the radon-releasing structure, an outlet duct from the reactor tank, the outlet duct being connected to a water consumption system, and a radon-gas outlet from the reactor tank. In a mixing structure, water from the first pump is mixed with water from the reactor tank with the aid of a second pump in order to produce such a water flow in the radon-releasing structure as results in effective radon release. The radon-releasing structure is in air communication with the surroundings of the reactor tank, so that air, via this air communication, is entrained with the water, which is supplied to the radon-releasing structure via the mixing structure, with a view to admixing air with the water and, hence, releasing the radon.

This invention relates to a water-purifying apparatus, which is especially adapted to reduce the radon content of radon-contaminated water and which comprises a reactor tank for treating the radon-contaminated water, a radon-releasing means arranged in the reactor tank to receive and treat water from a first pump adapted to supply water from a source of water containing radon-contaminated water, the water from the radon-releasing means accumulating in the reactor tank, an inlet duct extending between the first pump and the radon-releasing means, an outlet duct from the reactor tank, said outlet duct being connected to a water consumption system, and a radon-gas outlet from the reactor tank.
U.S. Pat. No. 4,371,383 teaches a radon-removal system intended to be arranged between a source of water and a pressure storage tank. According to the US specification, this system succeeds in removing 80-90% of the radon by aerating the water, but nevertheless does not possess the efficiency required to achieve results below the Swedish maximum permissible value of 500 Bq/l, if the contaminated water has a radon content of 5000 Bq/l or more.
SE 464,712 discloses a water-purifying apparatus which effectively removes, inter alia, iron and manganese from water. The Swedish technique is based on effective aeration of the water, a technique that has proved to be useful also when it comes to removing radon. However, radon-contaminated wells are often fairly deep (70-100 m), which means that the amount of water lifted is rather small, for instance 5 l/min. A much greater flow rate of at least 25 l/min is required for effective aeration of the water. When the flow rate is too small, the aeration is less effective, which of course has an adverse effect on the removal of radon.


An acoustic impedance-matching transformer includes a tapered acoustic energy transmission (metal) block, having an acoustic impedance less than that of a piezo-electric transducer in a metric direction toward that of the acoustic propagation medium of the waveguide, and by an amount that allows tailoring of the relative spatial dimensions of mating surfaces of the transducer and the block, so as to provide efficient broadband coupling of acoustic energy. The surface area of the end face of the block engaging the transducer is a corresponding fraction of the area of the transducer. The tapered block focuses acoustic energy toward the input aperture of the waveguide channel. The taper is determined in accordance with difference between the acoustic impedance of the aluminum block and that of a second acoustic wave propagation element, such as a quarter-wave section of plexiglass, interposed between the waveguide channel and the tapered block.

The present invention relates in general to laser beam scanning systems, and is particularly directed to a acoustic impedance transformer, which is interposed between a relatively large sized, electrically driven piezo-electric transducer and an acousto-optic medium. The acoustic impedance transformer is configured to effectively match the impedance of the acoustic transducer with that of the acoustic wave propagation medium of the acousto-optic waveguide.
FIG. 1 diagrammatically illustrates the configuration of a guided acoustic travelling wave lens devicexe2x80x94one that employs a relatively narrowly dimensioned traveling wave channelxe2x80x94as comprising a laser 10, the optical beam output 11 of which is focussed by a cylindrical lens arrangement 12 and deflected by a mirror 13 onto an acousto-optic beam deflector 14, to which an RF input signal is applied. The acousto-optically modulated beam is then reimaged by a further sphericalxe2x80x94cylindrical lens arrangement 15 onto a traveling lens cell 16, that contains a traveling wave lens transport medium 17 and a traveling wave lens launching transducer 18. The scanned beam is then imaged onto an image collection medium, such as a photographic film 19.
In a number of applications, the acousto-optic waveguide may be configured as a reduced height, guided acoustic travelling wave lens (ATWL) waveguide device, such as that diagrammatically illustrated at 30 in FIG. 2. In this type of acoustic wave guide architecture, a first end 32 of the waveguide has an acoustic wave input aperture 34 (to which an acoustic wave-launching piezo-electric transducer is coupled), at an input end of a relatively narrow (fluid-containing) channel 36, having a cross-section of width w and height h, where w greater than  greater than h.
For a non-limiting illustration of examples of. documentation describing such guided acoustic traveling wave lens devices, attention may be directed to an article entitled: xe2x80x9cOptical Beam Deflection Using Acoustic-Traveling-Wave Technology,xe2x80x9d by R. H. Johnson et al, presented at the SPIE Symposium On Optical, Electro-Optical, Laser and Photographic Technology, August 1976, FIG. 6 of which corresponds to FIG. 1, above, an article entitled: xe2x80x9cGuided acoustic traveling wave lens for high-speed optical scanners,xe2x80x9d by S. K. Yao et al, Applied Optics, Vol. 18, pp 446-453, February 1979, and the U.S. Pat. No. 3,676,592 to Foster.
In a reduced height guided wave device, because the acoustic transmission properties of the acoustic propagation medium (fluid) within the waveguide channel 36 are considerably different from those of the transducer being used to launch the acoustic wave into the waveguide, there is a substantial acoustic impedance mismatch between the transducer and the waveguide. Indeed, the acoustic impedance of the waveguide may be on the order of twenty or more times that of the transducer.
In such a circumstance, in order to provide significant energy coupling from the transducer to the waveguide""s acoustic propagation medium (e.g. water), the transducer must be allowed to resonate to very large internal power. This causes two problems. First, the acoustic transducer is prone to failure, as the result of the very substantial acoustic stresses required. Second, the bandwidth is limited.
In accordance with the present invention, this electrical and, acoustic impedance mismatch problem is successfully obviated by means of an acoustic impedance-matching transformer that is inserted between the acousto-optic medium and a piezo-electric transducer. The acoustic impedance-matching transformer is configured to effectively match the acoustic impedance of the acoustic transducer with that of the acousto-optic medium.
For this purpose, the acoustic impedance transformer is structured as a combination of steps and tapers, in the form of a cascaded series of acoustic propagation elements of successively decreasing acoustic impedance. At each interface between adjacent elements, the abutting surfaces or the elements are physically configured to provide an effectively acoustic impedance match between the elements, and thereby an efficient coupling of the acoustic energy from an element of relatively higher acoustic impedance material to an element of relatively lower acoustic impedance material. Over the length of the transformer, this sequential xe2x80x98steppingxe2x80x99 of the acoustic impedance and configurations of the abutting surfaces of successively adjacent elements operates to effectively match the acoustic impedance of the piezo-electric transducer to that of the liquid acoustic traveling wave lens.
The first acoustic wave propagation element of the transformer comprises a relatively dense, acoustic energy transmission material, such as a metal (e.g., aluminum) block. This first element has an acoustic impedance that differs (or is stepped down) from that of the piezo-electric transducer in a direction toward the relatively small acoustic impedance of the acoustic propagation medium (water) within the ATWL waveguide. In order to compensate for this difference in the acoustic impedances of the materials of the transducer and the aluminum block, the dimensions of the two materials in the direction of the step must be smaller than the acoustic wavelength in the respective material. To this end, the spatial dimensions of the surface of the block are larger than those of the abutting wave-launching surface of the transducer, and by an amount proportional to the inverse ratio of their respective acoustic impedances, whereby the resulting acoustic-coupling interface provides broadband efficient coupling of acoustic energy therebetween.
Although such dimensioning of the engaging faces of the piezo electric transducer and the aluminum block ensures efficient coupling of acoustic energy from the transducer into the aluminum block, the cross-section of the aluminum block at its acoustic energy receiving face adjoining the piezo-electric transducer is still larger than that of the acoustic wave coupling aperture of the waveguide channel. Also, the acoustic impedance of the aluminum block is considerably larger than that of the waveguide channel.
These differences are compensated by tapering the aluminum block toward the aperture of the waveguide channel, so as to focus the acoustic energy to a high acoustic energy density value at a reduced cross-section end face adjacent to the acoustic input aperture to the waveguide, and by providing a second transformer element between the reduced cross-section end face of the tapered aluminum block and the acoustic input aperture to the waveguide. The extent to which the first transformer block is tapered is determined in accordance with the difference between the acoustic impedance of the aluminum block and that of the second acoustic wave propagation element, such as a section of plexiglass or the like, so as to provide a compensating abutting surface area mismatch therebetween, as in the case of the piezo-electric transducer and the input end of the tapered aluminum block.
The plexiglass section has a cross-section corresponding to that of the acoustic input aperture of the waveguide. Since plexiglass has an acoustic impedance that is approximately twice that of water, it is configured as a quarter-wave plate section, so as to provide an acoustic impedance match between its interface with the reduced cross-section end of the tapered aluminum block and the waveguide.
The combined effect of the increased acoustic power density at the exit end of the aluminum block, the increased cross-sectional area of the plexiglass quarter-wave plate, and the ratios among the acoustic impedance parameters of the mutually adjoining aluminum block, quarter-wave plate and waveguide channel thereby provides an efficient, broadband coupling into the waveguide channel of acoustic energy originally launched from the piezo-electric transducer.

Stepped acoustic impedance-matching transformer for very narrow channel acoustic traveling wave lens waveguide


In a camera in which a 35 mm photographic roll film is used, a positive convex meniscus lens, the convex side of which faces an object to be photographed, an aperture diaphragm and a flare-stop facing an image side are provided. An image plane is curved toward the lens as the image plane advances away from the optical axis of the lens in the longer side direction of the focal surface. The following inequalities are satisfied: EQU 26.ltoreq.f.ltoreq.32 EQU f.sup.2 /126.ltoreq.F.ltoreq.16. in which f represents the focal distance and F represents the F-number of the lens.

The present invention relates to a compact fixed focus type camera or a lens unit having a film, and more particularly relates to a lens that is assembled to the camera or the lens unit.
Conventionally, a 35 mm-roll-film unit having a lens or a fixed focus type camera having a simple structure is provided with a lens, the focal distance of which is approximately 35 mm. The single lens applied to the aforementioned 35 mm-roll-film unit or fixed focus type camera is disclosed in Japanese Patent Application Open to Public Inspection Nos. 199351/1988, 246713/1988 and 106710/1990. In these patent applications, examples are disclosed in which an aspherical lens or a spherical lens, the focal distance of which is 33 to 50 mm, is combined with a diaphragm.
However, as the focal distance is 33 to 50 mm in the aforementioned examples, the total length of the lens and diaphragm is not less than 30 mm. Therefore, the depth of the cameras and film units (referred to as a camera, hereinafter) available on the market are not less than 35 mm, so that it is not easy to carry the cameras in a pocket. Recently, panoramic cameras have become popular, and wide-angle lenses by which an object and a background can both be photographed are widely used. For that reason, a simple camera provided with a wide picture-taking lens, the angle of which is larger than 35 mm, is required.


A MOSFET includes: a substrate; a gate insulating film; a gate electrode; an interlayer insulating film formed on the gate insulating film to surround the gate electrode; a buffer film containing Ti and N and containing no Al; and a source electrode containing Ti, Al, and Si. In the MOSFET, a contact hole is formed away from the gate electrode so as to extend through the interlayer insulating film and expose a main surface of the substrate. The buffer film is formed in contact with a side wall surface of the contact hole. The source electrode is formed on and in contact with the buffer film and the main surface of the substrate exposed by forming the contact hole.

1. Field of the Invention
The present invention relates to a semiconductor device and a method for manufacturing the semiconductor device, more particularly, a semiconductor device achieving a stable characteristic by improving adhesion between an electrode containing aluminum and an interlayer insulating film, as well as a method for manufacturing such a semiconductor device.
2. Description of the Background Art
An electrode containing aluminum (Al) may be employed for a source electrode of a MOSFET (Metal Oxide Semiconductor Field Effect Transistor) or an emitter electrode of an IGBT (Insulated Gate Bipolar Transistor). For example, in the MOSFET, a positional relation or the like between such a source electrode containing Al and each of a gate electrode, a gate insulating film, and an interlayer insulating film has been considered (for example, see U.S. Pat. No. 6,833,562 and Japanese Patent Laying-Open No. 2000-012846).
In the MOSFET, the source electrode may be formed on and in contact with a surface of a substrate having an active region formed therein, and in contact with a side wall surface of an interlayer insulating film formed to surround the gate electrode on the surface. Here, if adhesion between the source electrode and the interlayer insulating film is insufficient, the source electrode comes off, thus affecting a device characteristic of the MOSFET.

Semiconductor device and method for manufacturing same


A vacuum-cleaner suction tool includes a sucking portion for sucking up dust on a surface to be cleaned, a joint portion having one end connected to the upper side of the sucking portion and the other end provided with a connection pipe, and an agitator disposed within the sucking portion for scraping dust off the surface. The opening, the joint portion, and the connection pipe each have a channel portion allowing sucked-up dust to pass therethrough. The joint portion is configured to be turnable, relative to the sucking portion, in a horizontal direction substantially parallel to the surface to be cleaned to such an extent that the longitudinal central axis of the sucking portion becomes substantially parallel to the longitudinal central axis of the connection pipe, whereby the forward end of the sucking portion, from left to right, can be brought into close contact with wall surfaces so that dust liable to collect in corners can be fully sucked up.

A structure of conventional suction tool 1 will be described with reference to FIG. 14A and FIG. 14B. As disclosed in Japanese Patent Unexamined Publication No. 2002-102125, by operating handle 16 to apply turning forces thereto in leftward and rightward directions, suction tool 1 attached to the front end of handle 16 is turned around and brought from the state as shown in FIG. 14A into the state longitudinally oriented as shown in FIG. 14B, when viewed from the position of the user doing cleaning with handle 16 held in hand. Therefore, it becomes possible to advance suction tool 1 into a narrow space or to make cleaning at a portion close to a side wall.
At a position somewhat rearward from sucking portion 4, there is provided supporting portion 7 formed of a roller and the like for keeping sucking portion 4 parallel to the surface to be cleaned while suction tool 1 is moved back and forth.
In the described conventional configuration, however, because the turning center of sucking portion 4 is greatly deviated from the center of sucking portion 4 and also because supporting portion 7 described above is needed to be provided at the rear of sucking portion 4, the width of suction tool 1 becomes great when it is oriented in the longitudinal direction and, hence, it has been only the front portion of suction tool 1 that is then reachable into a narrow space.

Vacuum-cleaner suction tool and vacuum cleaner using the same

Matsushita Electric Industrial Co., Ltd.


The present invention relates generally to the field of release agents commonly in uses in preventing asphalt and other sticky compounds such as rubbers from sticking to the transporting vehicles such as dump truck beds and processing tools, and equipment, and more particularly to a novel biodegradable release agent applied to metal surfaces prior to use for promoting free release of sticky hot-mix asphalt materials from the metal tools and equipment used in road construction applications.

The invention relates to the field of release agents for use in preventing asphalt and other sticky compounds such as rubbers from sticking to the transporting vehicles such as dump truck beds and processing tools, and equipment, and more particularly to a novel release agent applied to metal surfaces prior to use for promoting free release of sticky hot-mix asphalt materials from the metal or plastic tools and equipment used in road construction applications.
Many roads are paved with asphalt produced on site or an asphalt plant in close proximity to an asphalt plant and is transported to the construction site in large trucks with metal beds, typically referred to as xe2x80x9cdump trucksxe2x80x9d. There the asphalt is spread and applied to existing asphalt pavement or a rock or concrete base, with shovels, rakes, and other metal tools usually in addition to a large paving machine and or grader. Problems occur due to the asphalt tending to stick on contact to any surface preventing total emptying of the load from a dump truck bed and adding unneeded weight to tools used to form and compress the asphalt in the selected areas. Since the asphalt is usually heated and is transported and applied in the hot state, the differentiation in temperatures between the asphalt and metal surfaces serves to cause sticking problems. Thus, the main disadvantage is that the sticking of the asphalt to the surface of the truck bed prevents the asphalt from smoothly sliding out of the metal truck bed as the dump truck attempts to discharge its asphalt load onto the road surface or into a paving machine. Time is wasted coaxing the asphalt out of the truck bed and the workers are exposed to hot asphalt which may contain petroleum based chemicals creating undesirable exposure to workers. Coating of the asphalt on to drums, storage tanks, trailers, piping, tires, and rollers causes cleanup and maintenance problems.
Conventional asphalt release agents known in the art to prevent asphalt from sticking to metallic surfaces were often based on chemicals commonly available at the construction site. For instance, kerosene or diesel fuel was often used to provide a release agent; however, these fuel oil based chemicals are flammable and often act as a solvent to dilute or cut the asphalt impairing the structural integrity of the asphalt product applied to the road surface. There are also environmental concerns relating to the use of fuel oil based release agents due to application and absorption of the oil based release agents into the ground and the evaporation of same especially in light of the exposure to the workers. Moreover, these traditional oil based cutting agents are not always effective against modern asphalt compositions.
An important consideration of the present invention is its effectiveness as an asphalt release agent for various compositions of asphalt in view of new types of asphalt mixes such as rubber based asphalt, asphalt containing polymers as well as conventional asphalt.
In the case of paving asphalt, a typical paving asphalt mixture comprises a mixture of components. The principal ingredients of the paving asphalt mixture being an asphalt composition or cement and aggregate or aggregate material usually containing rock and/or gravel. In such mixtures, the ratio of asphalt composition to the aggregate material varies, for example, according to the aggregate material type and the nature of the asphalt composition. As used herein, the terms xe2x80x9casphalt compositionxe2x80x9d or xe2x80x9casphalt cementxe2x80x9d are understood to refer to any of a variety of organic materials, solid or semi-solid at room temperature, which gradually liquefy when heated, and in which the predominant constituents are naturally occurring bitumens or residues commonly obtained in petroleum, synthetic petroleum, or shale oil refining, or from coal tar, or the like. For example vacuum tower bottoms produced during the refining of conventional or synthetic petroleum oils is a common residue material useful as asphalt composition. A xe2x80x9cpaving asphalt compositionxe2x80x9d or xe2x80x9cpaving asphalt cementxe2x80x9d, accordingly, is an asphalt composition or asphalt cement having characteristics which dispose the composition for use as a paving material, as contrasted, for example, with an asphalt composition suited for use as a roofing material. xe2x80x9cRoofing asphaltxe2x80x9d, for example, usually have a higher softening point, and are thus more resistant to flow from heat on roofs. The higher softening point is generally imparted to the material by the air blowing processes used for producing the material. Although the present invention can be used with any type of asphalt composition or aggregate mix therewith, paving grade asphalt are typically utilized with the present invention. Paving asphalt mixtures may be formed and applied in a variety of ways. For example, the paving asphalt composition and the aggregate are typically mixed and applied at elevated temperatures at the fluid state of the paving asphalt composition to form the pavement or road surface. However, the asphalt composition may also be applied in alternating layers with the aggregate mix.
The paving grade asphalt compositions may be composed of any know bituminous or asphaltic substance obtained from natural sources and/or derived from petroleum, shale oil, coal tar, and the like, as well as mixtures of two or more of such materials. The paving asphalt compositions are often referred to as viscosity or penetration grade asphalt, having original penetrations up to 400 as measured by ASTM method D%. Preferred asphalt are the normal paving asphalt such as AC2.5, AC5, AC10, AC20, AC30, and AD40. The designation xe2x80x9cACxe2x80x9d in the title define the xe2x80x9casphalt cementxe2x80x9d and the number indicates the viscosity at 60xc2x0 C. in poise multiplied by 100. Typical of such asphalt are the straight run asphalt derived from the atmospheric, steam and/or vacuum distillation of crude oils, or those asphalt derived from solvent precipitation treatments or raw lubricating oils and their fractions. Also included, are the thermal or xe2x80x9ccrackedxe2x80x9d asphalt which are separated as cracker bottom residues from refinery cracking operations and the asphalt produced as by-products in hydro-refining operations. A preferred asphalt is the vacuum tower bottoms that are produced during the refining of synthetic or petroleum oils. The asphalt may be treated or modified before use in the invention.
Inventions taught by the prior art typically employ an approach to formulation by providing a release agent which contains components capable of attacking asphalt material and therefore soften the asphalt in immediate contact with coating of the release agent applied on the surface of the transporting vehicles such as the bed of a dump truck used for hauling the hot-mix asphalt in road constructions. Such components include petroleum base oils such as diesel and biodegradable vegetable oils and animal fats. Although vegetable oils and animal fats are less aggressive than diesel whose use as an asphalt release agent is prohibited by law, they can still strip asphalt from the hot-mix at an elevated temperature commonly observed in road constructions and hence weaken the strength of the construction material which must meet strict criteria set between governmental and/or technical organizations such as the Department of Transportation (DOT) of US Government and local states. The stripping of asphalt from the hot-mix aggregates by release agents based on petroleum products or vegetable oils and animal fats often possess an unpleasant odor, attracting insects such as flies and therefore presenting a health hazard to the surrounding area nearby.
The invention is a composition for a release agent for use in preventing asphalt and other sticky compounds such as rubbers from sticking to the transporting vehicles such as dump truck beds and processing tools, and equipment, and more particularly to a biodegradable release agent applied to metal surfaces prior to use for promoting free release of sticky hot-mix asphalt materials from the metal or plastic tools and equipment used in road construction applications.
The present invention provides a release agent which, when applied as a coating on the surface such as a dump truck is loaded with the hot-mix and other processing equipment such as tools, drastically reduce the adhesion of asphalt to the surface, allowing hot-mix to slide out from the truck bed easily and cleanly. The release agent of the invention will not attack asphalt, therefore preserve the integrity of the hot-mix. The absence of any stripping effect of the release agent of the present invention is exemplified by the lack of asphalt film left behind on the truck bed after the hot-mix is unloaded from the truck. In fact, after the use of the release agent of the present invention, the truck bed would become cleaner and shinier. In addition, the release agent of the present invention is environmentally friendly, odorless, biodegradable and highly efficient.
One preferred composition of the asphalt release agent of the present invention provides a concentrate containing from about 1 to about 10% by weight PVA; from about 5 to about 40% by weight glycerol; from about 1 to about 20% by weight polyethyleneglycol; and optionally, but preferrably from about 0.001 to about 5.0% by weight of a wetting agent or surfactant, such as sodium dioctyl sulfosuccinate. An effective amount of a water soluble biocide may also be incoporated into the formula. The concentrate is diluted with water depending on the stickiness of the asphalt material. For example, a polymer modified asphalt liquid is typically stickier that a conventional grade containing no added polymeric materials and requires a stronger dosage of application of release agent typically in a ratio of 1 part concentrate to 4, 5, or 6 parts of water by volume. The conventional grade of asphalt may be diluted to 1 part concentrate to 19, 20, or 21 parts water by volume.
It is an object of the present invention to provide an asphalt release agent which is effective in preventing the sticking of asphalt to truck beds and other metal, plastic, paper, or wood surfaces.
It is an object of the present invention to provide an asphalt release agent which is innocuous and inexpensive.
It is an object of the present invention to provide an asphalt release agent which is environmentally safe.
It is an object of the present invention to provide an asphalt release agent which is soluble in water.
It is an object of the present invention to provide an asphalt release agent which does not dilute or affect the quality of the asphalt.
It is an object of the present invention to provide an asphalt release agent which can be applied with conventional spraying equipment.
It is an object of the present invention to provide an asphalt release agent which can be diluted with water before application depending upon the type and stickness of the asphalt.
It is an object of the present invention to provide a release agent which can be diluted with water and applied to concrete forms fabricated from wood or metal or onto the metal surface of the concrete container and conveying equipment.
The objects of the present invention will be more fully understood from the following description of the invention.
The present invention relates to novel release agent compositions and methods of applying such compositions to the metal and other surfaces which come in contact with asphalt materials. Although the release agent of the present invention is specifically designed for uses in prevention hot-mix asphalt from sticking to the appropriate surfaces, it is also expected to have utility as a release agent for a wide variety of materials such as other heavy hydrocarbons, plastics, and rubbers. The composition may also be employed as a biodegradable, environmental friendly dust suppressant for use in industrial processes such as with coal or limestone crushing operations, or in construction operations for settling dust formed by operation of heavy equipment or settling dust formed by cutting concrete in construction operations.
According to the present invention, a preferred composition of an asphalt release agent comprises a polymeric film former, a co-film former, a film modifier, and preferably, a wetting agent. An anti-microbial agent or preservative and a corrosion inhibitor can also be used. It is not necessary that each of these ingredients needs to be present in the composition in order for the composition to function as a release agent; however, the combination promotes optimal performance of the release agent.
In the preferred embodiment of the present invention, the preferred polymeric film former is polyvinyl alcohol (PVA). PVA is a water-soluble synthetic polymer made by alcoholysis of polyvinyl acetate. It is commercially available as a powder. Water solubility increases as the molecular weight decreases. The strength, elongation, tear resistance, and flexibility improve with increasing molecular weight. PVA decomposes at about 200xc2x0 C. It is unaffected by oils, greases, and petroleum hydrocarbons. It forms films by evaporation from a water solution.
PVA is commercially available as in grades defined by molecular weight-average ranging from 250,000 to 300,000. A molecular weight-average of from about 250,000 to about 300,000 is considered to be a super high viscosity product, a molecular weight-average of from about 170,000 to about 220,000 is considered to be a high viscosity product, a molecular weight-average of from about 120,000 to about 150,000 is considered to be a medium viscosity product, a molecular weight-average of from about 25,000 to about 35,000 is considered to be a low viscosity product.
The PVA constituents of the present invention have a molecular weight-average (MW) of between 100,000 and 300,000 and a degree of hydrolysis (DH) between 5% and 100%, more preferably a molecular weight-average of between 200,000 and 300,000 and a degree of hydrolysis between 20% and 99%; and most preferably a molecular weight-average between 250,000 and 300,000 and a degree of hydrolysis between 50% and 95%.
According to the present invention, a preferred co-film former is polyalkylglycol and derivatives thereof, such as polyethylene glycol, (xe2x80x9cPEGxe2x80x9d), glycol having molecular weight-average of preferably between 100 and 20,000; more preferably a molecular weight-average between 120 and 10,000; more preferably a molecular weight-average between 150 and 6,000, and most preferably a molecular weight-average of between 400 and 2,000.
In the instant composition, use of a polyethylene glycol as a co-film former tends to deaeriate the asphalt release agent solution, enhancing the coating or sheeting ability of the product and lowering the viscosity and preventing the formation of bubbles of the applied composition. Application to the surface to be treated at pressures of up to 300 psig (pounds per sq. inch gauge) tends to create bubbles and a foaming action which is not necessary and considered undesirable with the present composition.
Other condensation polymers or ethylene glycol compounds selected from the group consisting essentially of ethylene glycol, diethylene glycol, propylene glycol, triethylene glycol, dipropylene glycol, tripropylene glycol, 1-3 butylene glycol, hexylene glycol, and combinations thereof from about 80 to about 90 percent by weight.
In the preferred embodiment of the present invention, the film modifier or plasticizer is a poly-alcohol such as glycerol, (xe2x80x9cglycerinxe2x80x9d) or glycyl alcohol (xe2x80x9c1,2,3-propanetriolxe2x80x9d). The glycerol provides a water soluble plasticizing agent which adsorbs into and is compatible with the PVA. The glycerol aids in the solubilization of the PVA in water solutions which is important in that the asphalt release agent is prepared in as a concentrate. Moreover, the glycerol is also an antifreeze lowering the freezing point of the asphalt release agent. Although it is recommended that asphalt not be applied to the road surface when the outside temperature is less than about 45xc2x0 F., (7.2xc2x0 C.), the asphalt release agent may be stored or be exposed to lower temperatures without damage in part due to the glycerol within the formula. Thus, the glycerol aids in the film forming properties of the composition as well as the storage stability of same. Moreover, the ability to form a hydrophobic release coating at low temperatures provides a useful release agent for coating coal hailing rail cars and other aggregate containing hoppers which contain particles of material and may be exposed to freezing temperatures whereby moisture migrating to the metal surfaces of the containers tend to cause the aggregates to stick.
Although the preferred plasticizer is glycerol, other suitable plasticizers include polymerized glycerol, glycol ethers such as tetraethylene glycol, diethylene glycol, triethylene glycol, polyethylene glycol, other ether polyols, 1,3-butanediol, and combinations thereof.
In the preferred embodiment of the present invention, the wetting agent is an anionic, non-ionic, or cationic surfactant or any combination thereof. The wetting agents including surfactants are utilized in the preferred embodiments in ranges from about 0.001 to about 5% by weight, from about 0.01 to about by weight, and most preferably from about 0.05 to 0.5% by weight. An example of a preferred wetting agent is an anionic surfactant, sodium dioctyl sulfosuccinate.
The wetting agent lowers the surface tension of the asphalt release agent tending to enhance the spreading of the composition providing a more uniform coating over the container surface. The asphalt release agent of the present invention will spread without the use of a wetting agent; however, surfaces which have been exposed to asphalt prior to the application of the present invention tend to be hydrophobic as is the asphalt, and the addition of the wetting agent improves the dispersion of the coating.
It should be noted that although the wetting agent is a surfactant, the purpose of the wetting agent is not to promote foaming, for bubbles created in foam tend to burst creating thin spots, voids and uneven dispersion of the asphalt release agent. In the instant invention, a small amount of foam may be formed upon initial application due to the pressured spray application due to the use of a surfactant; however, any foam produced is quickly dissipated and sheeting of the composition is promoted upon the treated surface. Any foaming is primarily the result of mixing of the surfactants with gas, and therefor can be reduced, controlled, and/or eliminated by limiting the air or gas formed in the application process and equipment.
Other surfactants which may be utilized in the present invention include silicone glycols, alkylbenzene sulfonates, alcohol ethoxylates, phosphate esters, betaines, alkylphenol ether sulfates, alkylaryl sulfonates.
It may be desirable to include an effective amount of a biocide in the formulation if the solution is stored for a long period of time. Any conventional biocide compatible with the polymer blend can be used that is nontoxic to humans and does not effect the water-solubility of the composition. For example, the concentrate may contain a preservative such as sodium benzoate in an effective amount of from about 0.001 to 5.0% by weight.
The following examples provide preferred concentration ranges of the present invention and various formulas. All of the formulas contain PVA and PEG; however, the optimal formulations include a polyalcohol such as glycerol or glycerin, and a wetting agent.


A pressure device for a pinch roller of a VCR, which includes a pinch lever connected to a function plate which is mounted on the lower portion of a main chassis to be enabled to make reciprocating movement, a pinch arm connected to pinch lever, whereby when the function plate moves the pinch lever to rotate and this rotation is directly transmitted to the pinch arm so that a pinch roller is pressed against a capstan shaft by a predetermined pressure. Therefore, the pressure device of the present invention is simple in structure, effectively improves the operation thereof and remarkably reduces size of the VCR having the pressure device.

1. Field of the Invention
The present invention relates to a pressure device for a pinch roller of a video cassette recorder (hereinafter "VCR") and more particularly, to a pressure device for a pinch roller which is simple in structure so that the pressure device can efficiently improve its operation and productivity with low cost, and contribute to the simplification of VCR.
2. Description of the Prior Art
Various types of pressure devices for a pin roller of a VCR are well known in the art. One of such prior art pressure devices as shown in FIGS. 1 to 4 has a complicated structure. The conventional pressure device includes a function arm 2 disposed under a main chassis 1 for rotating by itself about a first shaft pin 3, on one end of the function arm 2, a function plate 4 is disposed for reciprocally moving through a guide pin in the direction indicated by arrow A as shown in FIG. 1. Since a locking pin 6 of the function plate 4 is inserted into a locking hole 2a of the function arm 2, the function arm 2 rotates in accordance with the movement of the function plate 4.
On the other end of the function arm 2, a first connecting pin 2b protrudes upward through a guide hole 1a of the main chassis 1. The first connecting pin 2b is provided with a first link 8 rotatably connected to the first connecting pin 2b at one end of the first link 8 to be always pressed to the left side of the drawing by elastic force of a first tension coil spring 7. Second and third links 9 and 10 are rotatively connected to the other of the connecting pin 2b through a second connecting pin 11.
A pinch lever 14 is connected to the second link 9 by a third connecting pin 15 and which is rotatably mounted on the main chassis 1 by means of a second shaft pin 12 of a pinch guide hole 14a and is resiliently supported by elastic force of a second tension coil spring 13 so that the second link 9 rotates in the clockwise direction. A pinch arm 19 having a pinch roller 18 which is pressed against a capstan shaft 17 is connected to the other of the third link 10 by a fourth connecting pin 20 and is rotatably mounted on a third shaft pin 16 of the main chassis 1.
Accordingly, as shown in FIG. 1, when play mode signals (not shown) of the conventional pressure device for the pinch roller of the VCR are applied in a stop mode while the pinch roller 18 is some distance away from the capstan shaft 17, the function plate 4 driven by a drive source (not shown) moves in the direction indicated by arrow A. Since the locking pin 6 of the function plate 4 is inserted in the locking hole 2a of the function arm 2, the function arm 2 rotates in a clockwise direction about the first shaft pin 3. And the first link 8 connected to the first connecting pin 2b of the function arm 2 overcomes elastic force of the first tension coil spring 7 and moves from the state shown in FIG. 1 to the state shown in FIG. 2. At the same time, the pinch lever 14 connected to the second link 9 overcomes the elastic force of the second tension coil spring 13 and rotates about the second shaft pin 12 in the counterclockwise direction. The pinch arm 19 connected to the third link 10 revolves in the counterclockwise direction about the third pin 16, thereby forcing the pinch roller 18 of the pinch arm 19 to contact the capstan shaft 17. At this point, the elastic force of the second tension coil spring 13 which supports the pinch lever 14, delivers the pressure force and forces the pinch roller 18 to press against the capstan shaft 17 as well. Additionally, the elastic force of the first tension coil spring 7, which supports the first link 8, works as the restoring force when the pinch arm 19 returns from the play mode to the stop mode.
However, the conventional pressure device for a pinch roller of a VCR has many components involved in the series of procedures by which the reciprocation movement of the function plate 4 is converted to a pressure movement which forces the pinch roller 18 to press against the capstan shaft 17. As a result, this large number of parts, and attendant cumulative size tolerances for the individual parts, reduce reliability of operation. In addition, large numbers of component parts increase production cost, decrease productivity, and hinder minimization of the sizes of products.

Pressure device for a pinch roller of a video cassette recorder


A system and method permits client-side locale specific numeric format handling in a web environment for software applications supported by programming languages. The system and method enable a software application supported by the programming language to perform client-side calculations on locale or user specific numeric data and display the numeric results in a format that is sensitive to the user's locale or specific needs. The system and method remove a locale specific or other numeric format for performing numeric calculations using the programming language and format the numeric data into one or more locale or user specific numeric formats for display.

1. Field
The present disclosure generally relates to web development and, more specifically, relates to systems and methods for processing locale specific numeric formatting in web browsers.
2. Description of the Related Art JavaScript™ is a scripting language which supports software applications on a variety of computer and computing devices regardless of the underlying operating system. The language has particular application in web documents, (e.g., Hypertext Markup Language (HTML) coded web pages) for processing or manipulating data in a web browser without invoking the web server. Such data manipulation is customarily referred to as client-side data manipulation. Currently, JavaScript™ is one of the most widely used scripting languages.
JavaScript™ technology, however, is deficient in handling and processing alternative numeric data formats which may be locale specific, i.e., numeric data formats which vary depending on the location of the client/user, and which contain characters not recognizable by JavaScript™. For example, in the United States, the number "one thousand five hundred forty-two and fifty-three cents" is customarily expressed and formatted by the client/user as "1,542.53". In Germany, the same number is formatted as "1.542,53". Regardless of the locale formatting utilized, JavaScript™ can only process this number when expressed as 1542.53.
Accordingly, software applications supported by JavaScript™ may be incapable of properly performing numeric calculations with numbers entered by the client/user using customary formatting symbols associated with the user locale. If a user in the United States types a number into a form on a web site with the comma grouping separator discussed above, JavaScript™ will not recognize the number as valid without additional manipulation of the data. Similarly, the period grouping separator methodology utilized in Germany is also unrecognizable by JavaScript™. Thus, in order for software applications supported by JavaScript™ to acquire universal and international applicability, it is necessary that these software applications handle and display numbers sensitive to the locale of the user.
Therefore, it is desirable to provide a system and method for client-side locale or user specific numeric format handling in a web environment, specifically, in a web browser. It may also be desirable to provide systems and methods for removing a locale or user specific numeric format for performing numeric calculations using JavaScript™ and then formatting the numeric data into one or more locale or user specific numeric formats for display purposes.

System and method for client-side locale specific numeric format handling in a web environment


Techniques and mechanisms for providing error detection and correction for a platform comprising a memory including one or more spare memory segments. In an embodiment, a memory controller performs first scrubbing operations including detection for errors in a plurality of currently active memory segments. Additional patrol scrubbing is performed for one or more memory segments while the memory segments are each available for activation as a replacement memory segment. In another embodiment, a first handler process (but not a second handler process) is signaled if an uncorrectable error event is detected based on the active segment scrubbing, whereas the second handler process (but not the first handler process) is signaled if an uncorrectable error event is detected based on the spare segment scrubbing. Of the first handler process and the second handler process, only signaling of the first handler process results in a crash event of the platform.

1. Technical Field
Embodiments of the invention generally relate to the field of computer memory and more particularly, but not exclusively, to handling of an error in a memory device.
2. Background Art
In today's computing world, maintaining good computer system reliability and uptime is often important or even mandatory. To maintain significant computer uptime, system designers build reliability, availability, serviceability, manageability (RASM) features to improve overall system reliability and availability. Thus, it is common to find various degrees of redundancy, error correction, error detection and error containment techniques employed at different levels in such a system.
One of the most common types of computer system failure is attributed to system memory errors. Memory devices are susceptible to errors such as transient (or soft) errors. If these errors are not handled properly, they can cause a computing system to malfunction. Hence, the memory subsystem (especially dual in-line memory modules or DIMMs) receives particular attention in this regard. For example, redundant information in the form of error correcting codes (ECCs) or other such error correction information can be used in memory scrubbing operations to improve overall system reliability. Demand memory scrubbing is one error detection/correction technique wherein errors in a memory segment, whether single-bit or multi-bit errors, can be detected in the course of operation to service a host operating system's requests to access the memory segment. By contrast, another RASM technique known as patrol memory scrubbing pro-actively scans a memory segment for errors before, or otherwise independent of, any such host operating system requests to access the memory segment.
Another RAS technique—known as "memory sparing"—allocates one or more memory segments each to be available for service as a spare segment in the event of an actual or expected future failure of an in-use (or "active") memory segment. When error detection or other mechanisms indicate such failure of an in-use memory segment, a spare memory segment is allocated to serve as a successor to (substitute for) the failed/failing segment. The system memory map is updated to associate addresses—e.g. a range of addresses—with memory locations of the successor segment, where previously such addresses were mapped to variously identify respective locations of the failed/failing active segment.

Method, apparatus and system for handling data error events with a memory controller


An optical system comprising a concave primary mirror reflects light through an intermediate focus to a secondary mirror. The secondary mirror re-focuses the image to a final image plane. Optical limiter material is placed near the intermediate focus to optically limit the intensity of light so that downstream components of the optical system are protected from intense optical transients. Additional lenses before and/or after the intermediate focus correct optical aberrations.

This invention relates generally to optical systems and, more particularly, to optical systems that are protected from intense optical transients by non-linear optical technologies.
Optical telescopes are used in research, commercial, and defense contexts for a variety of imaging and communications applications. Both imaging and non-imaging optical telescopes gather light within a field of view and focus it by means of optical elements onto a final focal plane where an optical sensor, such as a sensor array or a human eye, is placed. These features of conventional optical systems make them vulnerable to intense optical transients. For example, laser light that falls within the field of view of the telescope is gathered and focused by the optics of the telescope. The resulting concentration of optical energy can cause significant damage to components of the telescope, including the sensor array, or to other optical sensors, such as human eyes. For example, most remote sensing telescopes employ a sensor array positioned at the final focal plane, the position where the intensity of the incoming light is greatest. A laser beam of sufficient intensity within the field of view of the telescope can quickly overload and burn out such sensor array. In the case that an eye of a human observer is used directly as the optical sensor of the telescope, an unchecked intense optical transient could blind the observer.
Some of the traditional approaches to protecting optical systems from the threat of intense optical transients involve non-linear optical materials used as optical limiters to limit the optical intensity at the sensor array. In certain non-linear optical materials, the transmissivity of the material varies as a function of the intensity of the incident light. Certain non-linear optical materials are more transparent to low-intensity, ambient light but become more opaque as light intensity increases. These materials can be used to attenuate intense incident light. In other types of non-linear optical materials, the refractive index changes as a function of the light intensity. These materials can be used to defocus intense optical transients. Yet another class of non-linear optical materials has phase conjugating properties. These are traditionally gas cells which, when exposed to very intense optical radiation, both reflect and conjugate the optical phase of the incident light. To provide better response and greater protection, it is desirable to place the non-linear optical device where the intensity of the light is highly concentrated. Thus, the non-linear optical media is traditionally placed near a focal point such as just in front of the detector system.
Most of the optical telescopes used for remote sensing are of the aplanatic Cassegrain (Ritchey-Cretien or RC) design. These RC designs suffer from at least two principal problems when non-linear optical materials are used as protection against intense optical transients. First, these designs do not have a natural intermediate focal point. Therefore, additional relay imaging techniques are used to re-image the incoming light onto the final focal plane array. In many of the re-imaging approaches, the size of the protection device is roughly the same size as the focal plane array. Thus, in at least some systems, the non-linear optical device must be quite large. Second, although RC systems can be designed with shorter focal ratios (e.g., an f-number of F/3), RC systems used for remote sensing traditionally feature long focal ratios. For example, the Hubble Space Telescope, an orbital imaging satellite, features RC optics with an F/24 focal ratio. These slow optical systems result in large spot sizes and poor concentration of energy. The poor concentration of energy, in turn, results in a poor response of the non-linear optical materials which, in turn, decreases the degree of protection the non-linear material can provide against intense optical transients. In other words, at these low concentration ratios, the non-linear materials may not begin to "turn on" significantly until the laser intensity is already near or beyond the damage threshold for the optical sensor. Some of the more recent satellite-based telescopes feature a three mirror anastigmat (TMA) optical design. While markedly different from RC optical systems, these designs have the same disadvantages as RC optical systems when it comes to protection from intense optical transients.
Hence, there is a need for optical systems that facilitate improved performance of non-linear optical technologies for protection against intense optical transients. In addition, there is a need for optical systems which reduce the size of such non-linear optical devices.

Gregorian optical system with non-linear optical technology for protection against intense optical transients


In an embodiment, a technique for generating a comment for an entity associated with a model. The comment may be generated based on at least (1) a structural usage of the entity and (2) a dynamically-specified rule that is associated with the structural usage of the entity. The rule may be used to control content of the comment. The comment may be incorporated in generated code for the model and the generated code including the comment may be outputted (e.g., displayed, stored).

Modeling environments may include textual modeling environments and/or graphical modeling environments that may be used to generate, compile, and/or execute one or more models that represent systems. Modeling environments may cater to various aspects of dynamic system simulation, synthesis, analysis, and design. Such modeling environments may allow users to perform numerous types of tasks including, for example, constructing and simulating models.

This patent is subject to a terminal disclaimer.

Generating comments for code generated from a model


The present invention discloses an optic system for providing illumination and imaging functions in an optical navigation system. Generally, the optic system includes a unitary optic component having an illumination lens and at least one prism to project a collimated beam of light from a light source in the optical navigation system onto a surface, and an imaging lens to image at least a portion of the illuminated surface to an array of photosensitive elements. In one embodiment, optic system further includes an aperture component having a precision aperture, the aperture component configured to locate the precision aperture between the imaging lens of the unitary optic component and the array of photosensitive elements in a path of light reflected from the portion of the illuminated surface to the array of photosensitive elements. Other embodiments are also described.

Data input devices or finger navigation devices, such as computer mice, touch screens, trackballs, scroll wheels and the like, are well known for inputting data into and interfacing with personal computers or workstations. Such devices allow rapid relocation of a cursor on a monitor, and are useful in many text, database and graphical programs. A user controls the cursor, for example, by moving the mouse over a surface to move the cursor in a direction and over distance proportional to the movement of the mouse.
Computer mice, for example, come in both optical and mechanical versions. Mechanical mice typically use a rotating ball to detect motion, and a pair of shaft encoders in contact with the ball to produce a digital signal used by the computer to move the cursor. One problem with mechanical mice is that they are prone to inaccuracy and malfunction after sustained use due to dirt accumulation, etc. In particular, mechanical mice have not demonstrated the accuracy demanded in state-of-the-art mice today, which generally must have a path error of less than 0.5%. In addition, the movement and resultant wear of the mechanical elements, particularly the shaft encoders, necessarily limit the useful life of the device.
One solution to the above problems with mechanical mice has been the development of mice using an optical navigation system. These optical mice have become very popular because they provide a better pointing accuracy and are less susceptible to malfunction due to accumulation of dirt.
The dominant technology used today for optical mice relies on a light emitting diode (LED) illuminating a surface at or near grazing incidence, a two-dimensional CMOS (complimentary metal-oxide-semiconductor) detector which captures the resultant images, and software that correlates successive images to determine the direction, distance and speed the mouse has been moved. This technology provides high accuracy but suffers from a complex design and relatively high image processing requirements.
Another approach uses one-dimensional arrays of photo-sensors or detectors, such as photodiodes (PDs), and a narrowband or coherent light source, such as a Vertical Cavity Surface Emitting Laser (VCSEL). Light from the light source scattered off of an optically rough surface generates a random intensity distribution of light known as speckle. Successive images of the surface are captured by imaging optics, translated onto the photodiodes, and compared to detect movement of the mouse. The photodiodes may be directly wired in groups to facilitate motion detection. This reduces the photodiode requirements, and enables rapid analog processing. The use of a speckle-based pattern has several advantages, including efficient laser-based light generation and high contrast images even under illumination at normal incidence. This allows for a more efficient system and conserves current consumption, which is very important in wireless applications.
Although a significant improvement over prior mechanical mice, these optical navigation system based devices have not been wholly satisfactory for a number of reasons. In particular, VCSELs and PD arrays are typically formed on a substrate or wafer, using semiconductor fabrication or processing techniques. Individual devices, commonly referred to as a chip or die, are then packaged as separate integrated circuits (ICs), which may or may not then be attached or mounted to a common printed circuit board (PCB). Conventional optical navigation systems use external illumination and imaging optics that are not mounted to the IC package or PCB to illuminate a portion of the surface with light from the light source, and to map or image a pattern of the surface to the optical sensor.
One problem encountered with conventional, external optics, is that part they greatly increase the size or footprint of the optical navigation system. Another problem is that the alignment requirements of the optical elements of the illumination and imaging optics to the VCSEL or light source and the PD arrays can be critical to adequate performance of the system. It will further be appreciated that this alignment requirement can greatly impact overall costs and yield of the finished product.
Accordingly, there is a need for an optical navigation system that includes illumination and imaging optics for use in an optical data input devices or finger navigation devices that reduces the overall size and complexity of the system while enhancing system stability and reliability, and substantially reducing costs and increasing yield of the finished device.
The present invention provides a solution to these and other problems, and offers further advantages over conventional optical navigation systems.

System and method for illuminating and imaging a surface for an optical navigation system


Apparatuses, systems, and methods are disclosed for a speaker pool. A method includes receiving electronic consent from a plurality of speakers over an interface with a third party for the speakers to join a speaker pool. A method includes receiving criteria for selecting one or more speakers from a speaker pool from a third party via a hook in an interface. A method includes electronically displaying a selected one or more speakers from a speaker pool to a visitor of a third party using a hook in an interface based on received criteria.

Individuals may rely on their personal networks to find a person knowledgeable enough to answer their questions, evaluate various options, and/or provide specific suggestions rather than generic advice. Many times, individuals may not be fortunate enough to find such a person in their personal network and may instead compromise for sub-par, if not wrong, advice. Thereafter, they may end their efforts to seek inputs from a knowledgeable person. Or, a few courageous individuals may resort to other sources, like the Internet, to find such a person online, but may face multifold challenges—such as how to identify such a person, how to reach to such a person once identified, how to convince this person to join in a discussion, and how to engage them during discussion.

Apparatuses, systems, and methods for a speaker pool


The invention relates to a plug-in connector (1), in particular for airbag retaining systems, comprising a first housing (2, 3), which can be locked into a mating connector (7) by means of locking arms (4a, 4b) and a secondary locking mechanism (5) that can be impinged by a spring force. Said secondary locking mechanism (5) has tongues (6a, 6b), which block the locking arms (4a, 4b) once the latter have engaged in the mating connector (7), in addition to detent arms (8a, 8b), which are blocked by the introduction of one edge (9) of the mating connector (7) until the locking arms (4a, 4b) are engaged and which then slide off the edge (9) as a result of the spring force that has accumulated up to this point, pressing the secondary locking mechanism (5) into its final position.

In several respects, stringent requirements are placed on such plug-in connectors relative to the reliability of the connection that is produced and of the plugging-in process of a plug-in connector into its mating connector. In addition, the plug-in connection must be designed for a very long service life, during which fatigue phenomena of the seating of the plug must not occur.
A plug-in connector with a secondary locking mechanism is known from EP-1,207,591 A2, in which, during the plugging-in process of the connector into a corresponding mating connector and after the engaging of a primary locking mechanism, a secondary locking mechanism is moved into a slot between a tongue of the primary locking mechanism and the connector housing, in order to fill this slot and to prevent the primary locking mechanism from popping out of its locked position. In this case, the tongue of the secondary locking mechanism is continually under elastic strain in the final state, so that it may become subject to material fatigue, and, as the case may be, to material fracture over the long term. If pieces of the tongue of the secondary locking mechanism fall out of the slot, the secondary locking would therefore no longer be secure. At the very least, the correct seating of the plug-in connector in its mating connector would no longer be secure.
An electrical connector is known from DE 196 20,177 A1, in which an electrical contact between complementary connectors is first made toward the end of the plugging-in process in such a way that, during the plugging-in process, a spring is tensed, which moves the connectors into one another when a predetermined spring force has been exceeded and after release of its spring excursion.
DE 198 47,872 A1 describes an ignition bus housing with a secondary locking mechanism, which is pre-tensed by a spring during the plugging-in process and after engaging of the connector locking mechanism, moves by spring force over the connector lock and blocks it in its locking position.
In DE 100 05,858 A1, a spring clip acting as a safety device provides for the circumstance that the secondary locking can only take place when the connection of the connector has been concluded.
DE 100 35,726 A1 shows a contact support, in which a secondary locking mechanism is held back during the plugging-in process until the locking mechanism has been engaged. A spring tension is built up during the plugging-in process, and when this is released it moves the secondary locking mechanism into its final position. This release takes place after the spring tension has become large enough, due to the compression of the spring, in order to overcome an elastic resistance, which is formed by an elastic compressible clamp. The behavior of the latter determines the time point for triggering and this time can thus be determined only imprecisely and is hardly reproducible.
A plug-in connector with a secondary locking mechanism is known from EP 1,006,621 A1, wherein the secondary locking mechanism rests on one edge of the mating connector, until it is released by shifting laterally at a specific stage of the connecting process.

Plug-in connector comprising a secondary locking mechanism impinged by a spring


An ophthalmic drug dispensing system in the form of a hand held device constructed of a soft pliable material with a bleb or bulbous area in its forward portion. Contained within the bleb is a fluid chamber which is connected to an orifice located in one end of the dispensing system.. In use, the chamber is filed with a drug or medication and the device is inserted between the sclera of the eye and the upper eyelid with the bleb contacting the inner surface of the eyelid. Due to the pressure of the inner side of the upper eyelid upon the bleb, the drug or medication is forced from the chamber and out through the orifice by way of the channel.

It is commonplace in the field of ophthalmology to topically apply medication a patient's eye by applying a fluid onto the surface of the cornea of the eye. Due to the ease of administration; eye drops are administered to the lower fornix, the potential space between the eye and the lower lid. Recent research has indicated more used efficiency with eye drops placed into the upper fornix, the potential space between the eye and the upper lid, using conventional eye drop dispensers in order to apply drops under the upper lid, the patent will be placed in a supine position or will need to put his/her head back while facing the ceiling. For some patients this can be a problem due to physical infirmities, the lack of a bed to lie on, hand tremor and the difficulties with hand eye coordination. Another problem with the usual method of applying topical medicine is the use of preservatives which may irritate the eye and cause tearing with subsequent decrease in efficiency of the medication due to "washout."
In addition to the application problems traditionally associated with the use of eye droppers is the amount of medication needed to achieve a certain result. Studies have shown that if eye medication is applied beneath the superior fornix of a patient, the medication will have an increased absorption rate and increased duration. A recent article discussing this issue was published in the Journal of Ocular Pharmacology, by Vincent H. L. Lee, dated May 25, 1990. According to Dr. Lee, for the last twenty years the main effort has been to design systems to prolong the residence time of topically applied drugs in the conjunctival sac. The approach has been to minimize precorneal drug loss through prolongation of residence time of the drug in the conjunctival sac. The major route by which most ophthalmic drugs enter the eye is traditionally believed to be via the cornea. There is increasing evidence which shows that topically applied ophthalmic drugs can reach the posterior of the eye by diffusion across the conjunctiva-sclera laminate. This route is favored because there are drugs which are poorly absorbed by the cornea compared to a more posterior route, such as some anti-glaucoma medication. Micro-particulate systems, such as nanoparticles and microspheres, may favor non-corneal drug penetration since they may accumulate in the fornices. The present invention provides an ophthalmic drug delivery system specifically designed to promote non corneal drug penetration. As well as a prolonged and more effective method of corneal absorption through the upper fornix, lid administration.
For many patients an improved drug delivery system for ophthalmic drugs may be of critical importance. Medication which is absorbed through the eye will commingle with other medicines present in a patient's system. The combination of certain types and levels of medication can be problematic for the patient. However, this problem can be lessened by using eye medications which are applied in doses which are efficacious yet smaller than the amount which is used with current eye droppers.
Another problem with the use of eye droppers is sterility. When a dropper is used and then replaced back in its container, there is a chance that the medication could become contaminated. Currently applied medications require the use of a preservative in order to maintain their safe use and effectiveness including medicines that are designed for use in ocular insert devices. This is problematic since some patients have an allergic reaction or chemical reaction to the preservative contained in the medicine. This type of allergic reaction causes "washing out" of the medication due to the severe tearing of the eye.
Another problem with medications which are supplied in drop form or in a continuous use device, is the occurrence of side effects. Depending upon the makeup of a particular patient, some types of medication can cause psychosis, heart problems and even a accidental heart attack due to systemic side effects. Lower lid application of medications may be absorbed systematically especially after entering the nasal mucosa.

Method for dispensing ophthalmic drugs to the eye


A process for selectively making 2-thiols from alpha olefins is described. The process includes contacting a linear or branched alpha olefin having with H2S in the presence of a catalyst and recovering the 2-thiol from a product mixture. The catalyst includes a support and at least one metal selected from Group IIIA-VIIIA and the branched olefin is branched at the 3-position or higher with respect to the olefin double bond. Compositions wherein the 2-thiols are substantially free of 1-thiol and 3-thiol isomers are also described.

Mercaptans, also known as thiols, are organic compounds that are used in diverse applications. Some mercaptans are used as agricultural supplements or as polymerization process modifiers. When mercaptans are present in large quantities, they are generally considered to be malodorous and highly undesirable. But in low concentrations these same compounds are used as fragrances and flavorings. When used in this manner they can be an effective and economical replacement of more expensive natural products in a wide variety of perfumed articles such as soaps, detergents, powders, perfume and cologne, and even as flavoring agents. For example, mercaptans are commonly used in perfumes and cleaning supplies to impart a lavender scent. In foodstuffs and other products, mercaptan compounds are widely used to reproduce the taste and fragrance associated with black currant or grapefruit.
The variety of tastes and flavorings available can be attributed the numerous mercaptan compounds that can be synthesized. Yet, while numerous compounds can be made, economical processes for the production of even relatively simple mercaptans are not available in some cases. In other cases, the purity of known processes require difficult separation steps to obtain mercaptans of a desired purity.


A self-contained knob contains a bushing which fits on a control shaft of a control element and extends axially through each of an annular disk and a pedestal. The annular disk slidingly rests upon the pedestal. The disk and pedestal contain between them a pair of concentric, radially separated tracks of spring loaded balls and cavities. The balls momentarily engage the cavities in arc movement as the knob is turned. The pedestal receives at the bottom and is prevented from rotating by a fastener of the control element.

1. Field of the Invention
This invention pertains to a knob for control elements, more particularly, to a knob which is attached to a rotary shaft of a variable control element to provide a plurality of discrete, different, tactile signals to the operator, including discrete points of resistance to rotation of the shaft.
2. Description of the Prior Art
There are many designs patented for tactile feedback of shaft position provided by mechanisms within control elements including switches. Having the tactile feedback mechanism in a knob, however, simplifies the construction of a control element, reduces inventory and permits selection from a wider choice of control elements on the market in constructing a control system.
U.S. Pat. No. 3,662,618, patented by Kroll et al, May 16, 1972, describes a rotary instrument knob which contains a tactile feedback mechanism.
The knob is attached to the shaft of the instrument by a collet that fits symmetrically about the top of the shaft. A termination socket or bushing, which extends through the panel of the apparatus containing the instrument, has a circular groove at the bottom for attaching a fastener behind the panel. The bushing may also include an indexing finger through the panel or may be fastened to the apparatus by gluing or screwing in order to keep it from turning.
The shaft of the instrument passes upward through the bushing. Mounted on the shaft, above the bushing, is a ring holding balls in equally spaced relation from the shaft which momentarily engage depressions in the top of the bushing, as the ring is rotated by the shaft. Above the ring is a ball retaining disk that is pressed against the balls by a helical compression spring which is permanently concentrical in relation to the shaft. The spring is retained and guided axially, concentrically in relation to the shaft in a circular groove which extends around the shaft.


Included are n antenna sets; n antenna switch units; n signal change units each changing a combination of one or more of a phase, a timing, a frequency, and a power of each signal transmitted/received in n antennas being selected from the antenna sets; a notification unit outputting a notification signal, in which control information on the antenna switch units and the signal change units according to a target terminal being a destination/source of the signals transmitted/received in the n antennas, are arranged according to a switch time of each of the antenna switch units and a change time of each of the signal change units; and a control unit sequentially starting control of switching by each of the antenna switch units and control of changing by each of the signal change units in order in which the control information on the each unit in the notification signal is notified.

In recent years, with the spread of a high-performance portable wireless terminal, such as a smartphone, wireless LANs in compliance with the IEEE 802.11 standard have come into wide use not only in companies and public spaces, but also in ordinary houses. As the wireless LANs in compliance with the IEEE 802.11 standard, there is a wireless LAN in compliance with the IEEE 802.11b/g/n standard that uses a 2.4 GHz band, and a wireless LAN in compliance with the IEEE 802.11a/n/ac standard that uses a 5 GHz band.
In the wireless LAN in compliance with the IEEE 802.11b standard or the IEEE 802.11g, 13 standard channels are prepared at intervals of 5 MHz in a bandwidth of 2400 MHz to 2483.5 MHz. However, when using multiple channels in the same place, in order to avoid interference, channels that are not in the same band are used. In such a case, a maximum of three channels are used, and up to four channels can be used at the same time, depending on the place where the channels are used.
In the wireless LAN in compliance with the IEEE 802.11a standard, in Japan, it is stipulated that 8 channels in bands that do not overlap in a bandwidth of 5170 MHz to 5330 MHz and 11 channels in bands that do not overlap in a bandwidth of 5490 MHz to 5710 MHz, totaling 19 channels, should be used. It is noted that in the IEEE 802.11a standard, a bandwidth per channel is set to 20 MHz.
A maximum transfer speed in the wireless LAN is 11 Mbps in the IEEE 802.11b standard and is 54 Mbps in the IEEE 802.11a standard or the IEEE 802.11g standard. However, the transfer speed here is a transfer speed on a physical layer. Because a transfer efficiency in the Medium Access Control (MAC) layer is actually approximately 50 to 70%, an upper limit value of actual throughput is approximately 5 Mbps in the IEEE 802.11b standard and is approximately 30 Mbps in the IEEE 802.11a standard or the IEEE 802.11g standard. Furthermore, if the number of wireless stations that are going to transmit information increases, the transfer speed further decreases.
For this reason, in the IEEE 802.11n standard that results from completion of the standardization in 2009, a channel bandwidth was broadened from 20 MHz, which had been set up to that time, to a maximum of 40 MHz, and the introduction of the Multiple input multiple output (MIMO) technology was determined. When all functions that are stipulated in the IEEE 802.11n standard are applied, and thus transmission or reception is performed, it is possible that, in a physical layer, a communication speed of a maximum 600 Mbps is realized.
Moreover, in the IEEE 802.11ac standard that results from completion of the standardization in 2013, a channel bandwidth was broadened to 80 MHz or a maximum of 160 MHz, or the introduction of the multi-user MIMO (MU-MIMO) transmission scheme to which Space Division Multiple Access (SDMA) is applied was determined. When all functions that are stipulated in the IEEE 802.11ac standard are applied, and thus the transmission or reception is performed, it is possible that, in the physical layer, a communication speed of a maximum approximately 6.9 Gbps is realized.
In this manner, in the wireless LAN, the communication speed that accompanies the development in the standard that results from the standardization was improved. However, if the same frequency channel is shared among multiple wireless stations, it is known that throughput decreases due to a decrease in the number of communication opportunities that accompanies an increase in the number of wireless stations. In contrast to this, a technology is studied in which a power that caused interference to each wireless station is suppressed by adaptively controlling a transmission power of a wireless station conforming with a situation of a communication partner, and in which, as a result, the number of opportunities of each wireless station to perform communication is increased (Non-Patent Document 1: Vivek P. Mhatre, Konstantina Papagiannaki, and Francois Baccelli, "Interference Mitigation through Power Control in High Density 802.11 WLANs", IEEE INFOCOM 2007-26th IEEE International Conference on Computer Communications IEEE, 2007). Examples of a method of controlling a transmission power include a method of controlling amplitude of a transmission signal using a power adjustment apparatus such as a variable resistor or a variable amplifier.
FIG. 7 illustrates an example of a configuration of a wireless communication system that is assumed according to the present invention.
In FIG. 7, base stations 10-1 and 10-2 that are connected to a network 30 are configured to use the same frequency channel and perform wireless communication with terminals 20 under the control of the base stations 10-1 and 10-2, respectively. Furthermore, each of the base stations 10-1 and 10-2 includes multiple antennas and is configured to perform MIMO communication with one or multiple terminals 20. Moreover, the base stations 10-1 and 10-2 also include a function of adjusting a transmission or reception power of each antenna according to the terminal that is a destination.
FIG. 8 illustrates an example of a configuration of a base station in the related art.
In FIG. 8, the base station includes n (n is an integer of two or more) antennas 101-1 to 101-n, power change units 102-1 to 102-n that change a transmission power and a reception power, transmission and reception units 103-1 to 103-n that perform transmission processing and reception processing of signals that are transmitted or received, respectively, in n antennas, a signal processing control unit 104 that performs conversion processing of a signal that is input or output into or from a network that is connected to the base station, and the signal that is transmitted or received in each of the n antennas, a power notification unit 105 that outputs a notification signal that includes an amount of power change by each of the power change units 102-1 to 102-n in accordance with a target terminal that is a destination or source of the signal that is transmitted or received, and a power control unit 106 that performs control of power changing by the power change units 102-1 to 102-n according to the notification signal. It is noted that the power notification unit 105 is present within the signal processing control unit 104.
The power notification unit 105 extracts transmission power information that corresponds to each antenna for the target terminal that is set in advance, before performing the transmission processing, and notifies the power control unit 106 of the transmission power information that corresponds to each antenna. According to the notification signal from the power notification unit 105, the power control unit 106 performs control in such a manner that the transmission powers are changed by the power change units 102-1 to 102-n that correspond to the antennas 101-1 to 101-n, respectively. The same is true for the control of the reception power of a reception signal. Accordingly, because optimal transmission power control is performed on the target terminal, it is possible that a power that causes interference to any other wireless station is suppressed at the same time and that the number of opportunities for the entire wireless communication system to perform communication is increased. Thus, an improvement in throughput is expected.
Moreover, as a technology that increases an effect of reducing the transmission power, progress has been made in a study on a distributed antenna technology that arranges multiple antennas that the base station has, in a distributed manner and thus shortens a distance between a base station antenna and a terminal antenna, thereby resulting in an increase in the reception power of each wireless station (Non-Patent Document 2: Wan Choi, and Jeffrey G. Andrews, "Downlink Performance and Capacity of Distributed Antenna Systems in a Multicell Environment", IEEE Transactions on Wireless Communications 6.1 (2007): 69-73). On the other hand, although the reception power that increased is reduced, it is possible that the same communication quality as in the related art is secured. Because of this, a further reduction in the transmission power is also possible.

NIPPON TELEGRAPH AND TELEPHONE CORPORATION


A slew rate control circuit in output driver of switching circuit to prevent power ground undershoot is introduced. The gate capacitance of lower power transistor is first fast discharged to ensure the operation of the output signal. The gate capacitance of lower power transistor is then slowly discharged to limit OUT SLEW RATE. The gate capacitance of lower power transistor is further slowly discharged when the power ground level is below common ground. With above controlling, the gate voltage slew rate of lower power transistor is reduced when the lower power transistor is almost fully turned OFF. Therefore, undershoot at the power ground is avoided. Similar slew rate control circuit can also be derived in output driver of switching circuit to prevent PVCC overshoot.

1. Field of Invention
The present invention relates to in general a switching mode audio power amplifier and, more particularly, to circuits and methods for power Vcc/Ground overshoot/undershoot prevention and slew rate control in switching mode circuits and systems.
2. Description of Related Art
Class D audio power amplifier is one type of switching circuit. Therefore, Class D audio power amplifier is chosen for illustration purpose. Most of the audio power amplifiers in the market are based on Class AB amplifier. This architecture offers very good total harmonic distortion plus noise (THD+N) performance, with fairly low quiescent current. However, the Class AB push-pull amplifiers are very inefficient and can only achieve an efficiency of about 60%, which results in not only power loss, but also additional bulky heatsink attached to the power amplifiers.
One major advantage of Class D amplifiers is the efficiency, which could reach above 90%. The high efficiency is achieved by full signal swing at power transistors. A typical Class D amplifier circuit 1000 is shown in FIG. 1, which includes a pulse width modulator 1010, an upper level shifter 1020, a lower level shifter 1030, a first pair of complementary transistors M30 and M40, which drives a first MOSFET switch M10, and a second pair of complementary transistors M50 and M60, which drives a second MOSFET switch M20.
Due to the large transistor size of power transistors, the gate parasitic capacitance is large. In case wire path from power transistors to power supply or power ground is long, the parasitic inductance originated from these wires is large. The bonding wires from connecting power supply pads and power supply pin and bonding wires connecting power ground pads and power ground pin are also long, the parasitic inductance originated from these wires is also large. These parasitic effects are demonstrated in FIG. 1 as CG10, CG20, L10 and L20. In the actual operation of Class D amplifier circuit 1000, in case of heavy load, large current is flowing through power transistor M10 and M20 in a complementary way. Let us just take L20 as an example. From physics equation, we know the voltage across PGND and DGND can be expressed as:
      V              (              PGND        -        DGND            )        =            L      20        *                  ⅆ        i                    ⅆ        t            In case the circuit is heavily loaded, large switching current is flowing through lower power transistor M20. If M20 is turned off in a very short period, this large current is turned off as well. From above equation, we can predict that a large negative voltage is generated during this short period at power ground. For example, parasitic inductance L20 is assumed to be 0.1 nH, 10A current is turned off within a period of 1 ns, therefore,
      V              (              PGND        -        DGND            )        =            0.1      ×              10                  -          9                    *                        -          10                          1          ×                      10                          -              9                                            =                  -        1                                            V      It indicates that due to parasitic inductance on power ground wire, an undershoot voltage at power ground occurs with respect to digital ground when large current is quickly turned off at lower power transistor. FIGS. 5A and 5B show power ground undershoot in relation to fast slew rate of gate voltage of lower power transistor.
Undershoot at power ground causes noise, instability of the whole Class D amplifier circuit. Even worse, the Class D amplifier circuit is prone to latch-up when undershoot at power ground is large.
By observing the above equation, it is noticed that undershoot voltage at power ground is determined by 3 factors: parasitic inductance of power ground wire, current level at peak load and turn-off time of lower power transistor. To reduce undershoot at power ground, parasitic inductance of power ground wire can be reduced by increasing power ground wire width and shorten its length. However, this method increases chip size and its effect on parasitic inductance is not as significant as desired. Current level at peak load is a customer-defined parameter, which is not within the control of circuit designer. Turn-off time of lower power transistor is determined by parasitic gate capacitance of lower power transistor M20 and the size of discharging transistor M60. Parasitic gate capacitance CG20 is defined by customer-defined parameter efficiency and fabrication process, which is also not within the control of circuit designer. However discharging transistor M60 can be replaced with a self-adjusted discharging circuit, whose discharging speed is controlled by power ground voltage level. In other words, the slew rate of gate voltage at lower power transistor is controlled so that undershoot voltage at power ground is minimized.