A sealable container assembly with an internal, removable panel and a spout. The container assembly has a simplified construction that includes a container, a panel with a spout that is removably positionable inside an interior volume of the container and a lid that is removably attachable to the container to seal the interior volume of the container with the panel and spout positioned in the interior volume of the container.

There are many different types of container assemblies that are used by consumers to store food products such as breakfast cereal, snack foods, pet foods and other equivalent types of food products. A typical container assembly of this type is comprised of a container and a lid that is removable attachable to the container. In use, a food product is removed from its original packaging and poured into the container. The lid is then removably attached to the container to seal the container and keep the food product in the container fresh.
However, when the consumer desires to store a large amount of a food product such as pet food, it is often difficult to find a container assembly that is sufficiently large to store the large amount of food product. Furthermore, larger container assemblies often have an upright configuration with a height dimension of the container being substantially larger than the base dimensions of the container. This configuration of a container assembly, when filled with food product is often unstable on a shelf or other support surface.
Still further, when dispensing or pouring food product from a top opening of the container over an edge of the container that surrounds the top opening, it is at times difficult to direct where the food product is being poured.

Sealable container assembly with internal, removable panel and spout


The present disclosure relates to a plant for performing polymerization, such as the polymerization of ethylene, having a recycle connection with two or more cooling channels arranged in parallel, a process for polymerization and downstream processes, and a plant for polymerization, comprising the following plant components in fluid communication:                a) A reactor with an inlet side and an outlet side;        b) A recycle connection positioned in fluid communication between the outlet side of the reactor and the inlet side of the reactor; wherein the recycle connection comprises two or more cooling channels arranged in parallel.

The polymerization of ethylene is a process for the production of polyethylene or for the production of copolymers from ethylene with other comonomers. Polyethylene or such copolymers are employed extensively in both durable and disposable goods, particularly in the form of molded plastic parts or as plastics films. Plastic films and molded containers are used ubiquitously as packaging in the food and other retail industry. Other uses for molded plastic parts include but are not limited to consumer electronics, automobiles, domestic furniture and utensils, construction and medical applications.
EP 1 589 043 A2 explores the use of comonomers and chain transfer agents and their effect on the physical properties of a polymer product.
US 2010/087606 A1 explores the use of multiple feeds for introducing monomers and catalysts into a reactor and the effect on the physical properties of a polymer product.
US 2004/247493 A1 explores the effect of chain transfer agents on the physical properties of a polymerization product.
Given the economic significance of polymerization reactions, there remains a need in the art for improved polymerization processes and plants.

Polymerization plant having parallel cooling channels in a recycle connection


Disclosed is an air-applied, mechanically-held brake assembly and a vehicle air brake system employing the same. The brake assembly applies and releases the brake upon the supply and exhaust, respectively, of air from a first pressure chamber. The brake assembly locks and unlocks the brake in an applied position by the exhaust and supply, respectively, of air from a second pressure chamber. The locking mechanism of the brake assembly is designed to compound the force of the fluid pressure in the first pressure chamber with the force of the fluid pressure supplied to the second pressure chamber when unlocking the brake to compensate for back pressure.

1. Field of the Invention
This invention pertains generally to brake assemblies and air brake systems for heavy duty vehicles. More particularly, this invention pertains to a new air-applied, mechanically-held brake assembly and a new air brake system incorporating the new brake assembly for use with tractors, trailers, and tractor-trailer combinations.
2. Description of the Prior Art
Heavy duty vehicles such as tractors, trailers, and tractor-trailer combinations generally employ braking systems which operate on pressurized air. The vehicle brakes in such systems are controlled by the operation of brake assemblies which operate in response to the supply and exhaust of air under pressure received to and from the rest of the system. The industry is heavily regulated by the national governments of most developed countries and, as a consequence of these regulations, two types of brake assemblies have evolved. These two types are called "spring brakes" and "air-applied, mechanically-held brakes".
Spring brakes are so-called because they are activated for parking and emergency applications by large springs in the brake assembly. In a braking system employing spring brake assemblies, the brakes are applied and released for service applications by the supply and exhaust of air, respectively, to and from a first pressure chamber (usually called the "service chamber") of the brake assembly. The diaphragm of the first pressure chamber operates against a push plate to overcome the force of a return spring and apply the brake when air is supplied to the first pressure chamber. When air is exhausted, the spring returns the push plate to its original position thereby releasing the brake.
The brake of a spring brake assembly is applied and released for parking and emergency applications by the exhaust and supply, respectively, of air under pressure from and to a second pressure chamber of the brake assembly (usually called the "park chamber"). Thus, the exhaust of air releases a large spring to operate against a push plate to apply the brake. The brake is released by the supply of air under pressure to the same diaphragm, which operates against the push plate to overcome the force of the spring to release the brake.
The large springs in a spring brake assembly create several practical problems for the industry. The springs are typically heavy and bulky, and so spring brake assemblies are correspondingly heavy and bulky. These undesirable characteristics detract from the overall performance of the brake assembly and hence the entire brake system. This is especially true for the brake systems requiring relatively large numbers of brake assemblies to comply with governmental regulations for heavy duty vehicles. Spring brakes are also subject to weakened stroke, dragging and broken springs. Furthermore, spring brakes can be dangerous to maintain because of the large spring force, a problem which persists even when the assembly is properly disposed of, and in operation because they can be partially applied without the operator's knowledge. Newly manufactured spring brake assemblies pose additional problems because they are sealed when manufactured, thereby preventing, or at least seriously complicating, maintenance of the brake assembly.
Air-applied, mechanically-held brake assemblies overcome the above problems presented by spring brake assemblies. An air-applied, mechanically-held brake assembly applies and releases the brake in response to the supply and exhaust of air, respectively, to and from a pressure chamber much in the manner of the service chamber of a spring brake assembly. Typically, a diaphragm operates against a push plate upon the supply of air under pressure to overcome the force of the return spring to apply the brake, and, upon the exhaust of the air under pressure, the spring operates to return the push plate to its original position to release the brake. However, the brake is locked in an applied position by some mechanical means in response to the supply and exhaust of air. The mechanical means may vary depending upon the particular design of the brake assembly but all such mechanical means generally have the advantage of overcoming the problems associated with spring brake assemblies.
Such air-applied, mechanically-held brake assemblies are disclosed, along with an accompanying air brake systems, in the U.S. Patent Re. No. 29,913 issued Feb. 20, 1979 to Case et al., in U.S. Pat. No. 4,685,744 issued Aug. 11, 1987 to Ronald W. Luce. In the latter, air is supplied to and exhausted from the first pressure chamber of the brake assembly via a two-way shuttle valve. Once pressure is supplied to the pressure chamber and the diaphragm operates against the push plate to overcome the force of the return spring to apply the brake, air is exhausted from a piston in the brake assembly which has a pawl on the end of it. The piston drops when the air pressure is exhausted therefrom to permit the pawl to be spring pressed into engagement with a rack on the push rod attached to the push plate, thereby locking the brake in an applied position. The brake can be unlocked by supplying air under pressure to the piston to raise the piston and disengage the pawl on the end of the piston from locking engagement with the rack on the push rod. The brakes are thereby "mechanically held" by the rack and pawl engagement of the push rod and piston.
Another air-applied, mechanically-held brake assembly is disclosed in United States Statutory Invention Registration H748 obtained by John M. Graham and published Mar. 6, 1990. Graham employs a collet operating on the outside of the push rod driven by a diaphragm in response to the supply and exhaust of air under pressure to lock the brake in an applied position. In theory, the collet is driven into a tapered hole by the force of a spring when pressure is exhausted from the diaphragm, thereby clamping the push rod and preventing further movement. The brakes are consequently "mechanically held" in an applied position by the collet. However, as will be subsequently discussed, the design disclosed in Graham suffers from several fundamental flaws.
A third air-applied, mechanically-held brake assembly is the DD-3 brake assembly manufactured and sold by the Heavy Vehicle Systems Group of Bendix. The DD3 has a diaphragm which overcomes the force of a return spring on the supply of air under pressure. When air is exhausted from a piston operating the locking mechanism, the biasing force of a spring drives a plurality of rollers against an inclined surface that forces the rollers against the outside of the push rod to bind further movement. The push rod is thereby "mechanically held" by the binding force generated by the interaction of the rollers and the inclined surface.
One problem common to these and other mechanically-held brake assemblies not present in spring brake assemblies is back pressure on the push rod resulting from the cooling of heated brake drums. The drums of a vehicle's brakes become heated and expand during periods of intense or prolonged use. If the brakes are locked in an applied position while the brake drums are heated and are left locked for a period of time, the brake drums will cool and contract, thereby generating a back pressure on the push rod. The back pressure effectively magnifies the holding force locking the brakes, and creates severe problems unless adequately dealt with.
The control valve disclosed and claimed in U.S. Pat. No. 4,907,814 issued to International Transquip Industries, Inc. as the assignee of the inventor Nathan L. Goldfein on Mar. 13, 1990 addressed the back pressure problems facing the Case et al. and Luce brake assemblies. Although the brake assemblies work well in air brake systems with conventional control valves, the Goldfein control valve increases performance by manipulating pressures within the air brake system so that air at the peak pressure found on the diaphragm is used to allow the piston to raise and unlock the brakes. A greater force is therefore available to unlock the brakes than is found in the combined braking force exerted in applying the brake and the back pressure created by contracting brake drums.
The Graham brake assembly disclosed in Statutory Invention Registration H748 was apparently inspired by the need to effectively cope with additional forces generated by back pressure. The specification accompanying the Statutory Invention Registration H748 indicates that Graham intended that the locking means be axially movable in the brake "off" position in response to the presence of back pressure. However, among other things, the collet diaphragm is pierced through in several places in a manner which may prevent maintaining a seal at the necessary operating pressures.
It is therefore an object of this invention to satisfy both the technical and economical considerations in a manner which complies with governmental regulations and operate with currently used and installed air brake systems.
It is also an object of this invention to provide an operable air-applied, mechanically-held brake assembly for use with heavy vehicles which adequately deals with back pressure on the push rod.
It is furthermore an object of this invention to provide such an air-applied, mechanically-held brake assembly which is usable in air brake systems employing conventional valving.

Brake assembly with new locking mechanism

International Transouip Industries, Inc.


An electronic hand-muscle developer which includes a casing having a connector; a hollow flexible grip filled up with air and connected to the connector; a pressure inductor mounted in the connector to detect pressure from the hollow flexible grip; a pressure converter circuit mounted in the casing and connected to the pressure inductor to converts the pressure signal detected by the pressure inductor into a frequency signal; a microprocessor mounted in the casing to receive the frequency signal from the pressure converter, and to calculate the frequency signal so as to obtain a value; and a liquid crystal display connected to the microprocessor to display the value obtained by the microprocessor.

The present invention relates to hand-muscle developers, and relates more particularly to an electronic hand-muscle developer which shows the value of the pressure applied by the user.
Various hand-muscle developers have been disclosed, and have appeared on the market. These hand-muscle developers commonly use spring means to produce a resisting force against the pressure applied by the hand of the user. However, conventional hand-muscle developers cannot count and show the value of the pressure and the number of grips applied by the user.


A process for manufacturing a precast composite structure of a matrix of cured carbon fiber reinforced concrete and at least one ferrous metallic member at least partly buried in said matrix, by forming an insulating layer of an electric resistance of at least about 100 ohms at least on that surface of the ferrous metallic member, which will otherwise be brought in contact with a concrete mix, placing the metallic member in position in a mold, pouring into the mold a concrete mix containing 0.2 to 10% by volume of carbon fiber so that said metallic member may be at least partly buried in said concrete mix, partly curing the structure until it becomes self-supporting, de-molding the partly cured structure, and fully curing the structure in an autoclave at a temperature between 100.degree. C. and 215.degree. C.

The inherent brittleness of a cement matrix can be substantially overcome by dispersing therein a suitable amount of a suitable fibrous material, such as carbon fiber. Since the development of inexpensive pitch-based carbon fibers, extensive studies on a practical use of carbon fiber reinforced concrete have been made, and great expectations are entertained of this new construction material having strngth, distortion and elastic properties which have not been realized by the heretofore available cement concretes.
We have been engaged for a long year in a research and development work on the carbon fiber reinforced concrete. During our work we have encountered a problem which is not the case with ordinary concrete. The problem is a phenomenon that if metal is in contact with carbon fiber reinforced concrete, corrosion (oxidation) of the metal extensively proceeds during the curing of the concrete. More specifically, when carbon fiber reinforced concrete is cured while being in contact with ferrous metallic members, such as reinforcing steel bars and meshes, steel molds, bond wires, anchor fasteners, spacers and the like, corrosion of the metal rapidly proceeds during the curing of the concrete on those areas of the ferrous metallic members where they are in contact with the concrete to an extent unexpected with ordinary concrete.


The invention features an immunogenic composition containing a frequently-recognized epitope of an HIV-1 accessory protein such as Vpr and methods of inducing an immune response using such an epitope. The epitope peptide contains the amino acid sequence ALIRILQQL of a functionally active domain or a structural domain of the accessory protein.

The invention relates to immunity to T cell immunity to viral antigens.
Human Immunodeficiency Virus-1 (HIV-1) has infected over 57 million and killed over 22 million individuals worldwide since the beginning of the epidemic. More than 95% of HIV-1 infected individuals live in developing countries and have no access to antiretroviral treatment.
HIV-1 specific cytotoxic T lymphocytes (CTL) and T helper cells play a central role in controlling viral replication. Analysis of HIV-1-specific immunity has largely focused on assessment of immune responses directed against the structural HIV-1 proteins Gag, Pol and Env, as well as the accessory protein Nef. Recent data suggest that CTL responses directed against the early expressed regulatory proteins Tat and Rev also play a central role in the HIV-1-specific immune response. Despite advances in knowledge regarding HIV-1-specific immunity, the need for an effective vaccine remains great.

Methods of inducing an HIV specific response using a Vpr-specific epitope


A rail conversion module for a tractor allowing the tractor to be driven either on the ground or on railroad tracks wherein a hinged module frame fits under the tractor with front rail wheels on a frame front section being attached to the tractor and adapted to be raised for ground travel or lowered for rail travel and driven rear rail wheels on a frame rear section which by a hinge mounting can be raised for ground travel or lowered for rail travel.

For many years specially constructed traction vehicles have been available which operate both on roads and on railroad tracks. Typically they are small rail locomotives with four road wheels which can be raised to permit ordinary railroad travel on rail wheels or lowered to the ground so as to lift the rail wheels and permit road travel. Examples are the vehicles described in U.S. Pat. Nos. 3,198,137, 3,884,156, 4,067,259, 4,167,142 and 5,168,815. They are of relatively complicated design and quite expensive.
The object of the present invention is to achieve all of the major functions of these known specially built road-rail vehicles at a small fraction of their cost. This is achieved by utilizing a conventional farm tractor for whatever road travel is required of the road-rail vehicle, whether to pull loads or simply to move on the ground from one rail site to another. Then for rail operation a special conversion module is to be attached beneath the farm tractor. This module is to have vertically movable rail wheels which can be retracted upwardly to allow the farm tractor to continue its ordinary functions travelling on the ground. When rail travel is required the rail wheels are to be lowered to tracks so as to lift the tractor and elevate its road wheels off the ground. The tractor engine through its conventional power take-off is to drive the rail wheels and move the vehicle along the railroad track either alone or pulling railroad cars.


A transport hose floating on the sea surface and transporting petroleum or like fluid from a tanker to an oil reservoir installation on land or vice versa, comprising a leak detector operative in response to the presence of a leak fluid to indicate that portion of the transport hose at which a leak failure occurs.

1. Field of the Invention
This invention relates to an improvement in or relating to a transport hose floating on the sea surface and transporting petroleum or like fluid.
2. Description of the Prior Art
In the case of transporting crude oil, for example, from a tanker to an oil reservoir installation on land or vice versa, the tanker anchored off the shore is connected through a floating hose to a buoy installed off shore and the buoy is connected through a hose suspended therefrom and forming a suitable configuration line and a submarine pipe line to the oil reservoir installation on land. In such transport line, the hose required to be resilient, is subjected to a crack failure in its inner surface rubber layer due to aging of the rubber-like material. This often induces a leakage failure of the transport fluid out of the transport line due to separation in the joint between the nipple and rubber. As a result, the leaked crude oil floats on the sea and results in an ocean pollution or like disasters.
Under such circumference, if the fluid leak is not immediately found, the amount of fluid becomes considerably large to pollute the sea for a wide range in and around the leak point, thereby involving a tremendous loss. As a result, if the fluid flow through the hose begins to leak, it is necessary to find out the leak point as soon as possible and take necessary measures such as repair of the leak point or the like. In practice, however, early detection of the leak point has heretofore been extremely difficult since the transport hose is used on the sea surface.

Transport hose with leak detecting structure


A speaker box with pivotally installed divider providing an adjustable volume. One embodiment is a large, rectangularly shaped wooden speaker box which is centrally partitioned into two separate chambers, each of which houses one woofer. Each chamber contains a pivotally installed divider. A nut mounted on the divider is threadedly connected to a bolt which is rotated by a motor and which is mounted to the rear wall of the speaker box. Thus, when the motor rotates the bolt, the divider is pulled toward or pushed away from the rear wall of the speaker box. Regardless of the position, the moveable divider is a virtual rear wall of the volume and therefore defines the volume available for amplified bass. Another embodiment is a cylindrically shaped wooden tube which houses only one woofer. In much the same way as described for the rectangular speaker box, a circular divider is mounted within--allowing the amount of interior space used by the speaker to be adjusted.

It is a commonly known fact that speakers require some sort of exterior means by which to vibrate. Large bass speakers, more commonly called "woofers", have recently become very popular among the younger generation. Woofers, which are used to greatly amplify the lower registers of music such as rap and hip-hop, require a large space in which to vibrate and are thus attached to large, wooden boxes. These large speaker boxes are specifically designed to be used in the trunk of an automobile. While the greatly amplified bass produced by these speaker boxes works well with rap and hip-hop, it does not sound very good with music such as classical and opera, which do not require nearly as much bass. Thus, when one who is driving a car wishes to listen to music such as classical or opera, he or she has no choice but to listen to the large, bass-oriented speaker box which is installed in the trunk of the automobile.
Many speaker boxes have been designed with a large volume in order to provide greatly amplified bass. Many speaker boxes have also been designed with a smaller volume for the purpose of providing a normal amount of bass. There is no existing speaker box, however, which is able to provide both greatly amplified bass and normal bass.


A scanning probe microscope, capable of performing shape measurement not affected by electrostatic charge distribution of a sample, which: monitors an electrostatic charge state by detecting a change in a flexure or vibrating state of a cantilever due to electrostatic charges in synchronization with scanning during measurement with relative scanning between the probe and the sample, and makes potential adjustment so as to cancel an influence of electrostatic charge distribution, thus preventing damage of the probe or the sample due to discharge and achieving reduction in measurement errors due to electrostatic charge distribution.

1. Field of the Invention
The present invention relates to a scanning probe microscope technology capable of shape measurement not affected by electrostatic charge distribution of a sample.
2. Description of the Related Art
As a measurement technology of a microscopic 3D shape, a scanning probe microscope (SPM) has been known. The SPM, employing a technology of scanning a sample while a cantilever having a pointed probe is being controlled and a contact force is being kept at a very small value, has been widely utilized as a technology capable of measuring a microscopic 3D shape of atomic order. However, because scanning is performed by detecting deformation or an oscillating state to/of a cantilever while a contact force is being measured between a probe and a sample, the following problem occurs if the sample is electrically charged: the charge influences deformation or vibration state of the cantilever, causing an error in a shape measurement result by SPM.
For example, National Publication of International Patent Application Publication No. 2001-522045 (Patent Document 1) describes an apparatus for measuring charge distribution of a sample. In addition, Japanese Patent Laid-Open Publication No. 8-136552 (Patent Document 2) describes an atomic force microscope with a voltage control unit for applying a voltage to a cantilever and/or a sample and a similar type of scanning probe microscope and discloses that an interaction such as an electrostatic force which becomes noise in measurements can be canceled by applying voltage at approach by a coarse motion between the cantilever and the sample.
As described above, conventional technologies have the following problem: an error occurs in a measurement result of SPM due to an influence of electrostatic charge of a sample. Moreover, an object of the invention of National Publication of International Patent Application Publication No. 2001-522045 (Patent Document 1) described above is to measure charge distribution without measuring the shape of a sample and has not disclosed a method for accurately measuring the shape of a sample by relieving an influence of electrostatic charges. On the other hand, the invention of Japanese Patent Laid-Open Publication No. 8-136552 (Patent Document 2) simply compensates for interaction such as an electrostatic force at approach by a coarse motion and cannot accurately measure the shape of a sample with charge distribution taken into consideration.
In view of such problems, it is an object of the present invention to provide a method for obtaining an accurate measurement result by SPM without influences of electrostatic charge distribution of the sample.
Moreover, it is another object of the present invention to prevent a sample or a probe from being damaged by discharge between the sample and the probe.
It is yet another object of the present invention to prevent a probe and a sample from being damaged by discharge between the probe and the sample by issuing an alarm and stopping scanning if voltage adjustment amount is in excess of an allowable value during scanning.


Plural p+-type regions are formed on a silicon substrate, and thereafter, an n-type epitaxial growth layer is formed. Narrow concave portions are formed to extend between the surface of the epitaxial growth layer 14 and the silicon substrate and to have the almost the same lateral sectional shape. As a result, remaining parts, which are defined by the concave portions, of the epitaxial growth layer on p+-type field limiting rings are separated from the silicon substrate. Thus, a depletion layer is spread beyond the field limiting rings and a large forward voltage-resistance can be realized.

1) Field of the Invention
This invention relates to a static induction semiconductor device, particularly, a static induction semiconductor device including a one conduction-type semiconductor substrate, a one conduction-type epitaxial growth layer formed on a surface of the substrate, plural concave portions which extend from a surface of the epitaxial growth layer to the substrate and define plural one main electrode regions composed of the epitaxial growth layer, plural opposite conduction-type gate regions embedded in the respective channel regions between the adjacent concave portions, plural opposite conduction-type guard regions, each being formed under each concave portion, the other main electrode regions formed on the other surface of the semiconductor substrate, and plural opposite conduction-type field limiting rings surrounding the one main electrode regions, the plural channel regions, the plural gate regions and the plural guard regions.
2) Description of the Prior Art
The above-mentioned sort of static induction semiconductor device is known as a buried gate type static induction thyristor, for example. FIGS. 1-5 are cross sectional views showing successive steps to manufacture such a gate type static induction thyristor (SIThy). Herein, the manufacturing steps of one thyristor on a wafer will be described. First of all, as shown in FIG. 1, p-type impurities are implanted into a surface of an i-type (intrinsic) silicon substrate or a nxe2x88x92-type silicon substrate 111 at a predetermined energy and dose rate via a given mask, and are driven in to form P+-type regions 112 to constitute a guard region and, subsequently, a field limiting ring in a given pattern. Next, p-type impurities are implanted via a given mask, and driven in to form P+-type regions 113, which subsequently constitute a gate region. Herein, the junction of the P+-type regions 112 is formed deeper than that of the P+-type regions 113.
Subsequently, as shown in FIG. 2, an n-type epitaxial growth layer 114 is formed on the silicon substrate 111. In this case, the p-type impurities of the p+type regions 112 and 113 are diffused into the epitaxial growth layer 114. Thereafter, as shown in FIG. 3, an n+ type surface layer 114xe2x80x2 is formed on the n-type epitaxial growth layer 114 by the conventional diffusion method.
Next, as shown in FIG. 4, the epitaxial growth layer 114 having the n+ type surface layer 114xe2x80x2 is selectively etched on its surface, and thereby, concave portions 115 is so formed to extend to the P+ type regions 112. Channels 116 are composed of the sandwiched portions of the silicon substrate 111 by the adjacent concave portions 115. Then, one main electrode regions, n-type cathode regions 117 in this example, are formed from the sandwiched portions of the epitaxial growth layer 113, and guard regions 118 are composed of the p+ type regions 112. Moreover, at the same time of the formation of the concave portions 115, large region concave portions 119 are formed by etching the epitaxial growth layer 114 covering the channels, and thereby, field limiting rings 120, composed of the p+ type regions 112, are formed.
Moreover, as shown in FIG. 5, a silicon oxide film 121 is formed on the epitaxial growth layer 114, and the portions of the silicon film 121 above the n-type cathode regions 117 and the p+ type guard regions 118 are selectively removed to form cathode electrodes 122 and the gate electrodes 123. And then, on the other surface of the silicon substrate 111 are formed n-type regions 124, n+-type regions 125 and p+-type regions 126. The p+-type regions 126 constitute anode electrode regions as the other main electrode regions, and an anode electrode 127 is formed on the whole back surface of the silicon substrate 111 so as to be connected to the anode electrode regions. At the outside of the field limiting rings 120 are formed channel stop rings 128 having electrodes 129 thereon composed of the n-type epitaxial growth layer 114.
During operation of the SIThy, a direct current power supply is connected between the cathode electrodes 122 and the anode electrode 127, such that a forward main voltage is applied therebetween. If the thyristor is switched-on, positive signals for the gate electrode 123 to cathode electrodes 122 are input into. Just then, a main current is flown from the anode electrode 127 to the cathode electrodes 122 via channels 116. And, if a negative gate bias voltage for the cathode electrodes is applied to the cathode electrodes 122, electric charges are extracted from the gate electrodes 123, and thereby, the depletion region is enlarged from the gate regions 112 and the guard regions 118. As a result, the electric conduction through the channels 116 is shut down and no current is flown between the anode electrode 127 and the cathode electrodes 122. In this off-state, although the main voltage is applied between the anode electrode 127 and the cathode electrodes 122, the thyristor can have a large voltage-resistance because its electric field intensity is mitigated by the guard regions 118 and the field limiting rings 120 in the cathode electrode side.
In the conventional embedded gate type SIThy as mentioned above, the large concave portions 119 to form the regions including the field limiting rings 120 are formed in the forming step of the concave portions 115 which are elongated between the surface of the epitaxial growth layer 114 and the silicon substrate and define unit segments S in the cathode side. The concave portions 115 and 119 are formed by wet-etching using a mixed solution of hydrofluoric acid, nitric acid, acetic acid and so on. However, if the concave portions 119 is formed by the above wet-etching, they tend to have their shallow central portions as shown in FIG. 6. For example, although the concave portion 119 shown in FIG. 6 has a depth D1 of almost 17 xcexcm at both ends, it has a depth D2 of only almost 14 xcexcm at its central portion, which is smaller than the depth D1 by 3 xcexcm.
If the concave portion 119 does not have uniform depth over its whole region, the n-type epitaxial growth layer 114 partially remains at the upper sides of the field limiting rings 120, resulting in the difficulty of the whole spread of a depletion layer 130. That is, if the n-type regions exist on the spreading region of the depletion layer 130, the edge of the depletion layer is unlikely to spread and thus, a current field is concentrated at a smaller region than a predetermined region. As a result, a desired forward blocking voltage ability, that is, high blocking voltage can not be realized in the thyristor.
The cause of the shallow central portion of the concave portion 119 shown in FIG. 6 in the forming step of the field limiting ring 120 using wet-etching will be considered below.
In wet-etching, an etching solution is stirred and an additional etching solution is supplied constantly in order to perform the uniform etching process. In this case, the etching process is hindered if the gases generated in the above etching process are adsorbed on a surface of a material to be etched. In view of the above matter, Japanese registered utility model No. 1,827,697 discloses the technique of supplying the etching solution to the material from above in an oblique direction. If the etching solution is supplied from above in an oblique direction, the active etching reactive solution, including many etching species incorporated in the etching solution, is easily supplied to the edge portions of the concave portion to be formed because the edge portions are adjacent to the non-etched regions. On the other hand, the reaction-ended inactive etching reactive solution tends to stay at the central portion of the concave portion because the etching reaction occurs in the whole region of the central portion. As a result, the periphery of the concave portion is etched deeper than the central portion thereof. It becomes conspicuous when the etching process is carried out for a large region during a longer time by using an etching solution having a large self-catalytic rate controlling. Therefore, in the case of forming the wide concave portion 119 to form the field limiting rings 120, the large depth difference of 3 xcexcm is brought about between the periphery and the central portion of the concave portion, as mentioned above.
Moreover, a SIThy having a diode connected thereto in anti-parallel is proposed. For reducing a loop inductance in such a reverse conduction-type static inductive thyristor as small as possible, Shimizu et al. propose the technique of building the anti-parallel diode in the thyristor as a 4000V grade reverse conductive SI thyristor in the extended abstract, pp. 4-76, 4-77 of the l.E.E. Japan, 1998, for example. That is, in the conventional SI thyristor shown in FIG. 5, the anti-parallel diode is formed via the isolation region surrounding the active region including the channel 116, and the field limiting rings are formed at the outside of the anti-parallel diode.
In such a reverse conduction-type SIThy, the above isolation region have the same structure as that of the field limiting ring, and plural P+-type regions to constitute plural isolation regions are provided concentrically. For forming such an isolation region, a wider concave portion of several mm width is formed as in forming the field limiting ring regions. However, since the concave portion does not have uniform depth wholly, the n-type epitaxial growth layer remains partially at the tops of the plural isolation P+-type regions, so that the depletion layer, which is generated at the time of off-state of the SIThy, is not elongated beyond the isolation regions and the forward blocking voltage is degraded.
It is an object of the present invention to provide a static induction device having a sufficiently large forward blocking voltage through its enlarged depletion layer over the field limiting ring in order to maintain a large forward blocking voltage between its anode and cathode by removing the above structural inferality of the above conventional buried gate type static induction device.
It is another object of the present invention to provide a reverse conduction static induction semiconductor device having a sufficient large forward blocking voltage through its enlarged depletion layer over an isolation region between an active region and an anti-parallel diode and a field limiting ring region at the time of off-state of the semiconductor device.
It is still another object of the present invention to provide a method for manufacturing a static induction semiconductor device or a reverse conduction-type semiconductor device which have a sufficient forward blocking voltage.
The static induction semiconductor device of the present invention including a one conduction-type semiconductor substrate, a one conduction-type epitaxial growth layer formed on one surface of the semiconductor substrate. Plural concave portions are provided and extend from a surface of the epitaxial growth layer to the substrate and define plural one main electrode regions composed of the epitaxial growth layer, plural opposite conduction-type gate regions embedded in the respective channel regions between the adjacent concave portions, and plural opposite conduction-type guard regions, each being formed under each concave portion. Other main electrode regions are formed on the other surface of the semiconductor substrate. Plural opposite conduction-type field limiting rings are provided surrounding the one main electrode regions, the plural channel regions, the plural gate regions and the plural guard regions. Each of the field limiting rings is formed under a part of the one conduction-type epitaxial growth layer sandwiched by the respective adjacent concave portions extending to the one surface of the semiconductor substrate from the epitaxial growth layer.
A reverse conduction-type static induction type semiconductor device according to the present invention includes a one conduction-type semiconductor substrate having a one conduction-type epitaxial growth layer formed on one surface of the semiconductor substrate. Plural concave portions are provided and extend from a surface of the epitaxial growth layer to the substrate and define plural one main electrode regions composed of the epitaxial growth layer, plural opposite conduction-type gate regions embedded in the respective channel regions between the adjacent concave portions, and plural opposite conduction-type guard regions, each being formed under each concave portion. Other main electrode regions are formed on the other surface of the semiconductor substrate. Plural isolation rings are provided surrounding the one main electrode regions, the plural channel regions, the plural gate regions and the plural guard regions. Each of the isolation rings is composed of an opposite conduction-type region between respective adjacent concave portions extending to the one surface of the semiconductor substrate from the surface of the epitaxial growth layer under the epitaxial growth layer. An anti-parallel diode is provided having an emitter region composed of an opposite conduction-type surface region formed at the one conduction-type semiconductor substrate and at least the epitaxial growth layer. Plural field limiting rings are formed on the outside of the anti-parallel diode, each field limiting ring being composed of an opposite conduction-type region between respective adjacent concave portions extending to the one surface of the semiconductor substrate from the surface of the epitaxial growth layer.
A method for manufacturing a static induction semiconductor device in accordance with the present invention will be discussed below. As explained above, the static induction semiconductor device includes a one conduction-type semiconductor substrate having a one conduction-type epitaxial growth layer formed on one surface of the semiconductor substrate. Plural concave portions are provided and extend from a surface of the epitaxial growth layer to the substrate and define plural one main electrode regions composed of the epitaxial growth layer, plural opposite conduction-type gate regions embedded in the respective channel regions between the adjacent concave portions, and plural opposite conduction-type guard regions, each being formed under each concave portion. Other main electrode regions are formed on the other surface of the semiconductor substrate. Plural opposite conduction-type field limiting rings are provided surrounding the one main electrode regions, the plural channel regions, the plural gate regions and the plural guard regions, each field limiting ring being formed under a part of the one conduction-type epitaxial growth layer sandwiched by the respective adjacent concave portions extending to the one surface of the semiconductor substrate from the epitaxial growth layer.
The manufacturing method includes the following steps. Opposite conduction-type regions are formed to constitute the guard regions and the field limiting rings selectively at the one surface of the one conduction-type semiconductor substrate. Opposite conduction-type regions are formed to constitute the gate regions selectively at the one surface of the one conduction-type semiconductor substrate. The one conduction-type epitaxial growth layer is formed on the one surface of the semiconductor substrate. The concave portions, which define the channel regions and the field limiting rings, are formed so as to be extended to the one surface of the semiconductor substrate from the epitaxial growth layer. Electrodes are formed for the guard regions at the bottoms of the concave portions to define the channel regions, and electrodes are formed for the one main electrode regions formed above the channel regions and the other main electrode regions formed on the other surface of the semiconductor substrate.
A method for manufacturing a reverse conduction static induction semiconductor device according to the present invention will be described below. As explained above, the reverse conduction static induction semiconductor device includes a one conduction-type semiconductor substrate having a one conduction-type epitaxial growth layer formed on one surface of the semiconductor substrate. Plural concave portions are formed to extend from a surface of the epitaxial growth layer to the substrate and define plural one main electrode regions composed of the epitaxial growth layer, plural opposite conduction-type gate regions embedded in the respective channel regions between the adjacent concave portions, and plural opposite conduction-type guard regions, each being formed under each concave portion. Other main electrode regions are formed on the other surface of the semiconductor substrate. Plural isolation rings are formed surrounding the one main electrode regions, the plural channel regions, the plural gate regions and the plural guard regions, each isolation ring being composed of an opposite conduction-type region between respective adjacent concave portions extending to the one surface of the semiconductor substrate from the surface of the epitaxial growth layer under the epitaxial growth layer. An anti-parallel diode is provided having an emitter region composed of an opposite conduction-type surface region formed at the one conduction-type semiconductor and at least the epitaxial growth layer, and plural field limiting rings formed at the outside of the anti-parallel diode, each field limiting ring being composed of an opposite conduction-type region between respective adjacent concave portions extending to the one surface of the semiconductor substrate from the surface of the epitaxial growth layer.
The method includes the following steps. Opposite conduction-type regions are formed to constitute the guard regions, the isolation rings and the field limiting rings selectively at the one surface of the one conduction-type semiconductor substrate. Opposite conduction-type regions are formed to constitute the gate regions and the emitter region of the anti-parallel diode selectively at the one surface of the one conduction-type semiconductor substrate. The one conduction-type epitaxial growth layer is formed on the one surface of the semiconductor substrate. The concave portions are formed to define the channel regions, the isolation rings and the field limiting rings so as to be extended to the one surface of the semiconductor substrate from the epitaxial growth layer. An opposite conduction-type surface region is formed to constitute the emitter region of the anti-parallel diode in the epitaxial growth layer. Electrodes are formed for the guard regions at the bottoms of the concave portions to define the channel regions, and electrodes are formed for opposite conduction-type surface regions to constitute the one main electrode regions formed above the channel regions, the other main electrode regions formed on the other surface of the semiconductor substrate and the emitter region of the anti-parallel diode.
In the above static induction semiconductor device and the manufacturing method according to the present invention, it is desired that the concave portions to define the field limiting rings and, in some cases, the isolation rings have almost the same size as that of the concave portions to define the channels. Thereby, the etching process can be performed uniformly for all the concave portions and thus, the fluctuation in the depths of the concave portions can be repressed. For example, in the case of forming plural ditches having almost 40-60 xcexcm widths and 15 xcexcm depth at the same wafer by etching, it is confirmed that the fluctuation in the etched depths is within 1 xcexcm.
Moreover, in the present invention, it is desired that the reverse conduction-type guard regions, the reverse conduction-type field limiting rings and, in some cases, the isolation rings are joined by the same junction depth which is larger than the depths of the reverse conduction-type gate regions. Thereby, the depletion layer is absolutely elongated to the lower side of the guard regions, the field limiting rings and the isolation rings, and the local concentration of the electric field can be mitigated, so that the forward voltage-resistance can be more enhanced.

Edge structure for relaxing electric field of semiconductor device having an embedded type diffusion structure


A low profile, two pole, plunger-type safety switch and connector assembly includes a switch housing and switch components are supported within the housing interior region. An actuator extends exteriorly though the housing opening and is moveable along a linear path of travel between two positions, one position of the actuator corresponding to an undepressed position and a second position of the actuator corresponding to a depressed position. Terminals of the switch assembly terminate in conductive male contacts extending through a side wall of the switch housing substantially perpendicular to the path of travel of the actuator. The connector assembly includes a connector housing supporting four female terminals sized to snugly receive respective different ones of the four male contacts when the connector housing engages the switch housing. Extending arms of a flexible, electrically conductive shorting member contact a center two of the female terminals. When the connector is engaged with the switch housing a pair of beveled triangular shaped nubs extending from the switch housing contacts the shorting member arms and deflects them away from contact with the female terminals. When the connector is not engaged with the switch housing, the shorting member arms contact the two center female terminals creating a closed circuit condition in a circuit that the female terminals are electrically coupled to.

Plunger switches are widely utilized in many diverse applications including use as safety switches in various motorized devices. For example, U.S. Pat. Nos. 5,424,502, issued Jul. 27, 1993 to Williams, entitled QUICK-INSTALL SEAT SWITCH and assigned to the assignee of the present invention discloses a plunger switch and quick install mounting assembly for mounting the plunger switch on a rigid seat pan of a garden or lawn tractor. The '502 patent is incorporated herein in its entirety by reference. The switch assembly disclosed in the '502 patent is a single pole plunger switch that is a switch with two terminal contacts, the plunger switch electrically coupling or decoupling the two terminals depending upon the plunger or actuator position. The mounting assembly of the '502 patent affixed the plunger switch to the seat pan such that the actuator extends above the seat pan and the switch housing was below the seat pan.
A cover overlies the actuator. When the operator is seated on the seat cushion, the cover is forced downward by the deflection of the seat cushion thereby depressing the actuator from its first undepressed position to a second depressed position. If the switch assembly was a normally closed switch (i.e., the terminals were electrically coupled with the actuator was in its first undepressed position) and the switch assembly terminals were electrically coupled between the tractor engine magneto and an electrical ground of the tractor, the tractor engine would be shut off whenever the operator stepped (or fell) off of the tractor seat. That is, actuator would return to its first undepressed position thereby closing the electrical connection between the magneto and electrical ground resulting in the magneto being grounded out and stalling the engine.
With additional switches and/or relays appropriately mounted and connected, more sophisticated safety functions could be accomplished, for example, shutting off the engine only if the operator was not sitting on the seat and the tractor's mowing blade and/or power take off was engaged. U.S. Pat. No. 5,190,019, issued Mar. 2, 1993 and entitled INTERLOCK CIRCUIT FOR DE-ACTIVATING AN ENGINE, also assigned to the assignee of the present invention discloses such a circuit. The '019 patent is incorporated in its entirety by reference. Once again, a single pole seat mounted safety switch was contemplated.
While the tractor seat pan mounted plunger-type safety switch disclosed in the '502 patent provided a securely mounted switch that was easy to mount, such a switch (and other such prior art seat mounted safety switches) provided only a single circuit (one pole) switch. With the desire for additional operational fail-safe safety functions on lawn and garden tractors and riding lawn mowers such as turning the engine off if the cutting blade is engaged and the tractor is shifted into reverse, there is a need for a safety switch having more than one pole, thereby avoiding the necessity of duplicate switches and/or relays. Further, because of limited mounting room below the seat pan, it is desirable that the switch housing and connector be configured to minimize the height of the assembly extending below the seat pan, that is, along an axis of movement of the actuator. Additionally, it is desirable to prevent an operator from bypassing the operation of the safety functions provided by a seat mounted safety switch by simply disengaging the connector coupled to the switch housing.

Low profile, double pole safety switch and connector assembly


An electrical connection system includes a plug connector and a socket connector mated with each other. The plug connector includes an insulative housing having a mating face defining a plurality of channels therein for each receiving a plug contact element. Each plug contact element includes a mating section extending along a first axis substantially normal to the mating face of the plug connector and having a tip portion extending beyond the mating face. The socket connector includes an insulative housing having a mating face defining a plurality of passageways therein corresponding in position to the channels of the plug connector. Each passageway has a socket contact element fixed therein. Each socket contact element includes a mating section located in the passageway and extending along a second axis substantially parallel to the mating face. The mating faces of the plug and socket connectors are overlappingly engageable with each other whereby the tip portions of the plug contact elements are inserted into the passageways and engage with the corresponding mating sections of the socket contact elements in a substantially perpendicular fashion.

1. Field of the Invention
The present invention generally relates to an electrical connection system comprising a socket connector and a plug connector mated with each other, and in particular to an electrical connection system wherein contacts of a plug connector are brought into engagement with contacts of a socket connector in a direction substantially normal thereto.
2. The Prior Art
An electrical connection system comprising a plug connector and a socket connector mating with each other is well known in the electronics field. Connectors of this type are disclosed in Taiwan patent application Nos. 84213256 and 85201191.
The plug connector and the socket connector both have contacts engageable with each other. Conventionally, the contacts of the plug and socket connectors engage with each other in a parallel fashion. In other words, the contacts of the plug connector and the contacts of the socket connector are substantially parallel to each other during the engagement process. To ensure proper engagement between the plug contact and the corresponding socket contact, at least one of the contacts forms a bent section. Furthermore, the relative position between each socket contact and the plug contact must be precise to obtain proper electrical engagement therebetween. Such precise positioning of the contacts in the connectors increases overall manufacturing costs and the likelihood of unstable electrical engagement.
It is thus desirable to have an electrical connection system wherein the contacts of the plug and socket connectors engage with each other in a perpendicular fashion.


Methods of drilling with a wellbore fluid may include pumping the wellbore fluid with an oxidative degradable polymer into a wellbore with and an inactivated oxidant; forming a filtercake in a downhole environment, allowing some of the fluid to filter into a subterranean rock formation to produce a filtercake containing the oxidative degradable polymer and inactivated oxidant; and removing the filtercake formed by the wellbore fluid from the wellbore walls by exposing the filtercake with a breaker fluid comprising an aqueous fluid, and at least one iminodiacetic acid or a salt thereof.

1. Field of the Invention
Embodiments disclosed herein generally relate to wellbore fluids for forming and subsequently removing filtercake residue from subterranean formations.
2. Background Art
During the drilling or completion of an oil and gas well, the walls of oil and gas formations are often exposed to wellbore fluids which may damage producing formations. To prevent such damage, a wellbore often requires the deposit of a low-permeability filtercake on the walls of the wellbore to seal the permeable formation exposed by the drilling operation. The filtercake functions to limit drilling fluid losses from the wellbore as well as protect the formation from possible damage by the fluids filtering into the walls of the wellbore. Solids, such as particulate fines, suspended in the drilling fluid may also contribute to damaging hydrocarbon producing formations.
To protect formations from damaging fluids and solids, a filtercake is formed and/or deposited on the surface of the subterranean formation. Filtercakes are formed when particles suspended in a wellbore fluid coat and plug the pores in the subterranean formation such that the filtercake prevents or reduce both the loss of fluids into the formation and the influx of fluids present in the formation. A number of ways of forming filtercakes are known in the art, including the use of bridging particles, cuttings created by the drilling process, polymeric additives, and precipitates. Fluid loss pills may also be used where a viscous pill comprising a polymer may be used to reduce the rate of loss of a wellbore fluid to the formation through its viscosity
After drilling or completion operations have been completed, removal of filtercake (formed during drilling and/or completion) remaining on the sidewalls of the wellbore may be necessary. Although filtercake formation and use of fluid loss pills are essential to drilling and completion operations, the barriers can be a significant impediment to the production of hydrocarbon or other fluids from the well if, for example, the rock formation is still plugged by the barrier. Because filtercake is compact, it often adheres strongly to the formation and may not be readily or completely flushed out of the formation by fluid action alone.
Typically filtercake residue is removed by filling the open hole section with a clean up fluid (often referred to as a breaker fluid) that attacks the filtercake. In some situations, such as wells with gravel packed completions or other types of screen/slotted liners, ensuring that the treatment effectively contacts the filtercake on the wellbore face can present challenges. For example, in the case of unconsolidated formations, where it is often desirable to gravel pack the wellbore after drilling an interval but before the filtercake is completely removed, the act of gravel packing the wellbore may further limit the fluid's contact with the filtercake, as it both reduces the physical volume of fluid that can be present in the zone and restricts direct flow to the filtercake. As a consequence, the effectiveness of the breaking of the filtercake is dramatically reduced.
One of the most problematic issues that exist with many of the methods used by the prior art references in removing the filtercake downhole, includes the problem of controlling the breaking of the filtercake so that production fluids may not enter the wellbore before the entire, or at least most, of the filtercake is degraded. When degrading a filtercake with a breaker fluid, the breaker fluid may not have completely covered the entire interval of exposed formation, causing premature flowing of production fluids or the loss of breaker fluids into the formation from one portion of the interval before another portion has even been exposed to breaker fluid.
Accordingly, there exists a continuing need for wellbore fluids that effectively remove filtercake residue and debris in subterranean formations after drilling or completing a well.


High-frequency transistors are formed on a semiconductor substrate. Each transistor includes an emitter having a fish-bone structure, a base formed to surround the emitter, and a base lead region connected to the base. A resistor layer having the same conductivity type as that of the base lead region, and an impurity concentration and a junction depth equal to those of the base lead region is formed in the substrate. An emitter electrode is connected to the emitter and the resistor layer. A portion of the emitter electrode connected to the resistor layer has an interdigital structure, and is connected to the resistor layer at two or more contact surface portions or an interdigital surface portion. An electrode on the wiring layer side is connected to the resistor layer. A portion of the electrode connected to the resistor layer has an interdigital structure which matches with the interdigital structure of the emitter electrode.

1. Field of the Invention
The present invention relates to a semiconductor device, especially, a high-frequency output transistor and, more particularly, to an emitter stabilizing resistor connected to an emitter region of the transistor stabilizing the transistor and preventing damage to the transistor upon overloading.
2. Description of the Related Art
A so-called emitter stabilizing resistor (ESR) (or emitter series resistor) is disclosed, e.g., in Japanese Patent Publication Sho 52-3787. The ESR is formed by, e.g., an impurity layer formed in a semiconductor substrate. The ESR is used to improve the stability of a transistor a signal having a large magnitude is applied and to increase a breakdown voltage. The ESR requires the sheet resistance of greater than 1 to less than 100 .OMEGA./.quadrature.. However, when the ESR is formed by an impurity layer, in order to obtain this sheet resistance, the impurity layer must be formed by a special process. In addition, the ESR may be formed by, e.g., a metal thin film in place of a diffusion layer. However, the metal thin film is not preferable because the sheet resistance of the ESR formed by the metal thin film may generally only be reduced to 10 .OMEGA./.quadrature. due to limitations of the material. As a method of decreasing the resistivity of the ESR, it is effective to increase the diameter of a lead hole of the resistor. However, when the diameter of the lead hole is increased, the size of the entire ESR is also increased. Therefore, parasitic capacitance is increased, and the capacitance connected to the emitter in parallel is increased. This parasitic capacitance degrades the high-frequency operation of the transistor.
As described above, in the prior art, it is difficult to reduce the resistivity of the ESR while retaining good high-frequency characteristics.

High-frequency semiconductor device having emitter stabilizing resistor and method of manufacturing the same


An ultrasonic measuring apparatus of the type having a pair of transducers disposed oppositely on a pipe through which a fluid to be measured flows and which are so controlled alternately as to convert an input electrical signal to an acoustic signal and to convert a received acoustic signal to a received electrical signal. The apparatus includes a time difference detecting means for receiving an output signal from a delay means and the received electrical signal for detecting a time difference between a delayed counting time obtained from the delay means and a propagating time required for an ultrasonic wave to propagate through the fluid to be measured. Comparing means are provided for comparing a voltage signal corresponding to the time difference with first and second set voltages and monitoring means receiving the comparison result from the comparing means for judging whether the fluid flow is propagated in the pipe in a normal condition or in an abnormal condition. The present invention ensures a quick detection of abnormal propagation of the ultrasonic wave in the pipe and obtains a correct measurement values without misjudgement.

1. Field of the Invention
The present invention relates to an ultrasonic measuring apparatus of the type having a pair of transducers disposed oppositely on a pipe through which a fluid to be measured flows and which are so controlled alternately as to convert an input electrical signal to an acoustic signal and to convert a received acoustic signal to a received electrical signal, oscillating means having a variable oscillating frequency, a counter for counting the output signal from the oscillating means to produce an output signal when the count value of the counter reaches a predetermined value, a delay means for delaying the output signal from the counter, a transmitter receiving the output signal from the oscillating means for producing the input electrical signal, a time difference detecting means receiving the output signal from the delay means and the received electrical signal for detecting the time difference between the delayed counting time obtained from the delay means corresponding to the counting time that the counter counts the output signal from the oscillating means up to the predetermined value and the propagating time required for an ultrasonic wave to propagate through the fluid to be measured, controlling means for controlling the oscillating frequency of the oscillating means so as to make the time difference zero, and means for detecting the propagating time in accordance with the oscillating frequency of the oscillating means. A frequency difference between the oscillating frequency when the ultrasonic wave is emitted into the flow in a forward direction with respect to the flow direction and the oscillating frequency when it is emitted in a backward direction with respect to the flow direction is used to measure the flow speed or flow rate.
2. Prior Art
An ultrasonic flow rate measuring apparatus of this type is disclosed in an article "Fuji Ultrasonic Flowmeter" on pp 29 to 38 of "Fuji Giho" published by Fuji Electric Co., Ltd., Vol. 48, No. 2. The construction of this conventional ultrasonic flow rate measuring apparatus is shown in FIG. 1. In FIG. 1, reference numeral 10 designates a measuring pipe through which a fluid flows in the direction of the arrow. Mounting elements 15 and 16 mount transducers 13 and 14 on the outer surface of the pipe 10.
The transducers 13 and 14 convert acoustic signals into electric signals and vice versa. In one operation mode, the transducer 13 serves as a transmitter and the transducer 14 serves as a receiver. In another operation mode, the transducer 14 operates as an acoustic transmitter and the transducer 13 as an acoustic receiver. These modes are changed one to the other by a mode changer 9. The mode changer 9 produces mode switch signals A and B, which control the transducers 13 and 14 via a gate circuit 6 so as to alternately serve as the transmitter and the receiver.
In the figure, reference numeral 1 designates an oscillator unit having a pair of voltage controlled oscillators 11 and 12 and controllers 19 and 20. In the oscillator unit 1, the control voltages are varied by the controllers 19 and 20 in accordance with the output signal from a time difference detector 8 so that the oscillating frequencies are varied. The mode change signals A and B also control the controllers 19 and 20 in such a way that, in a given mode, one of the oscillators 11 and 12 accepts the output signal from the time difference detector 8. Reference numeral 2 designates a synchronizing (sync) pulse generator for producing a signal in synchronism with the output signal of the oscillator 11 or 12 selected by the mode changer 9. Reference numeral 3 designates a counter for counting the output signal from the oscillator unit 1. The counter 3 starts its counting operation in response to the output signal from the synchronizing pulse generator 2. When the count value of the counter 3 reaches a given value N, it produces a count operation end signal. Reference numeral 4 designates a delay circuit which initiates its operation in response to the output signal from the counter 3 to produce an output signal after a given time lapse. The delay time .tau..sub.d of the delay circuit 4 is substantially equal to the total time .tau. of the time taken for an ultrasonic wave propagating through the measuring pipe 10 and the time taken for an electrical signal to pass through a transmitter 5 and a receiver 7. The output signal V from the delay circuit 4 is led to the time difference detector 8. The transmitter 5 transmits an electrical signal to drive the transducers 13 and 14 on the basis of the output signal from the sync pulse generator 2. The output signal from the transmitter 5 is selectively applied through the gate circuit 6 to the transducer 13 or 14. Similarly, the receiving signal received by the transducer 13 or 14 is led through the gate 6 to the receiver 7.
The receiver 7, upon the detection of the receiving signal, produces a trigger signal Z to control the time difference detection circuit 8. As shown in FIG. 2 illustrating a circuit diagram of the time difference detector 8, a NAND gate 100 is provided in the prestage of the circuit. To the NAND circuit 100 a trigger signal Z from the receiver 7 and an output signal V from the delay circuit 4 are applied. When those signals Z and V coincide with each other causing the NAND gate 100 produce an output signal F of logical "1", the transistor Q1 which has been conductive is turned off so that charge current flows from a constant current circuit 90 into a capacitor through a diode D1 to charge the capacitor C. The constant current circuit 90, the transistor Q1, the diode D1 and the capacitor C cooperatively form a ramp circuit. The output signal of the ramp circuit, i.e., the charge voltage across the capacitor C, is led to a differential amplifier 80. A set voltage E50 for measuring the propagation time is preset in the differential amplifier 80 and the difference voltage between the output signal R from the ramp circuit and the set voltage E50 is derived as an output signal S from the time difference detector 8. This output signal S is led to the controllers 19 and 20 in the oscillator unit 1. The control voltages of the oscillators 11 and 12 are so controlled that the difference voltage becomes zero. As a result, the oscillating frequency is varied and the varied frequency is counted by the counter 17 to be converted into a propagation time t which is then applied to a display unit 18. A field effect transistor Q2 may be used to provide a path for discharging the capacitor C. The field effect transistor Q2 is controlled to perform on-off switching by a signal K. In this embodiment, the set voltage E50 may be selected to be approximately 5 V.
In operation, it is assumed that the mode change signal A is first produced from the mode changer 9 and accordingly the transducer 14 is forced to operate as the receiver and the transducer 13 is forced to operate as the transmitter, while at the same time the oscillator 11 in the oscillator unit 1 is connected to the sync pulse generator 2 and the counter 3. The gate circuit 6 is so controlled that the output signal from the transmitter 5 is led to the transducer 13 and that the output signal from the transducer 14 is led to the receiver 7. After the lapse of a given time, the delay circuit 4 produces the output signal V which interrupts the production of an output signal F from the NAND circuit 100. Accordingly, the capacitor C of the ramp circuit starts its charging. Then, the output signal is generated from the transducer 14. When the impingement of the ultrasonic wave on the transducer 14 is detected by the receiver 7, the receiver 7 stops generation of the output signal Z, so that the output signal F from the NAND circuit 100 is again produced, leading to the interruption of the charging into the capacitor C. The output signal from the ramp circuit at this time is denoted as R' hereinafter. The output signal R' is compared with the set voltage E50 and a resultant difference voltage .epsilon. therebetween is produced as an output signal S of the time difference detector 8. The oscillating frequency of the oscillator 11 is controlled by the difference voltage .epsilon.. Through the repetition of such an operation, the difference voltage finally becomes zero, that is to say, the output signal R' is controlled to be equal to the set voltage E50. In this manner, when the ultrasonic pulse is emitted into the flowing fluid in the forward direction with respect to the fluid flow, the forward propagation time Ta is transformed into a corresponding oscillating frequency of the oscillator 11. In this way, the forward direction propagation time measurement is completed.
Then, the mode changer 9 produces the mode change signal B. As a result, the transducer 14 is changed to operate as the transmitter while the transducer 13 is changed to operate as the receiver. At the same time the signal B controls the oscillator 12 in the oscillator unit 1 to be connected to the sync pulse generator 2 and the counter 3. The gate circuit 6 is so controlled that the output signal from the transmitter 5 is led to the transducer 14 and the output signal from the transducer 13 is led to the receiver 7. When the ultrasonic pulses are emitted into the flowing fluid in the backward direction with respect to the fluid flow, in the same manner as mentioned above, the backward propagation time Tb is transformed into a corresponding oscillating frequency of the oscillator 12. At this point, the measurement of the backward propagation time is completed.
The frequency difference between the frequencies of the oscillators 11 and 12 is derived as a frequency difference proportional to the flow speed from the reversible counter 17 and is applied to the display unit 18 where this difference is displayed as the flow rate or flow speed.
In FIG. 1, l and t related to the measuring pipe 10 are representative of the propagation distance of the ultrasonic wave in the measuring medium and the propagation time, respectively. In the apparatus shown in FIG. 1, the counting time required for the counter 3 to count N of the oscillating frequency f of the oscillator unit 1, is expressed by N/f. In this example, a feedback loop is formed so that this counting time coincides with the acoustic wave propagation time t in the measuring medium. Therefore, at the time point that the propagation becomes stable, N/f=t, i.e. f=N/t is obtained and therefore the frequency f thus derived is N times as long as the reciprocal of the propagation time, l/t. Accordingly, the propagation time t may be measured by counting the frequency f.
The ultrasonic wave is easily affected by the conditions of its propagation path. Therefore, it is necessary to carefully monitor its propagation, that is to say, whether the ultrasonic wave propagates normally or not. For such a monitoring, a conventional technique has employed the use of a signal monitor circuit (see Japanese Laid-Open patent application No. 101,668/1976) or an abnormality value removal circuit.
The above-mentioned signal monitor circuit judges whether the peak value of the receiving waveform falls within a given range or not. However, when the receiving waveform is distorted by, for example, the absorption of the ultrasonic pulse by bubbles in the flowing fluid, an erroneous signal may be generated indicating that the ultrasonic pulse has reached the receiving transducer; that is to say, a so-called mistriggering takes place. In the latter case of the abnormal value removal circuit, when the final output value (an average value over 5 seconds) is considerably different from the previous output value (an average value over 5 seconds prior to the final output), that value is judged to be abnormal. Accordingly, the final value is not derived as data while its previous value is held. The response of the flow rate measurement, therefore, is slow. Further, a sudden change of the output signal caused by a sudden change of flow speed or level might be misjudged as an abnormal situation.


A unibody piston and former for a speaker. The unibody piston and former including a piston having a sound radiating portion and a transition portion radially outward to the sound radiating portion, the sound radiating portion and the transition portion having a first interior angle that is less than one-hundred and eighty degrees. The unibody piston and former further including a former extending from the transition portion, the former and the transition portion forming a second interior angle, and the former and the piston are a unibody structure.

In modern consumer electronics, audio capability is playing an increasingly larger role as improvements in digital audio signal processing and audio content delivery continue to happen. There is a range of consumer electronics devices that are not dedicated or specialized audio playback devices such as smart phones and portable timepieces, yet can benefit from improved audio performance. These devices, however, often do not have sufficient space to house high fidelity speakers. This is also true for portable personal computers such as laptop, notebook, and tablet computers, and, to a lesser extent, desktop personal computers with built-in speakers. Such devices typically require speaker enclosures or boxes that have a relatively low rise (i.e. height as defined along the z-axis) and small back volume, as compared to, for instance, stand alone high fidelity speakers and dedicated digital music systems for handheld media players.
The drivers (speakers) for such devices therefore typically use a low profile diaphragm assembly, which is composed of a diaphragm or sound radiating surface (SRS), a voice coil and optional former or bobbin for connecting the voice coil to the SRS, and a suspension member for suspending the entire assembly from a frame. The voice coil causes the SRS to vibrate axially thereby creating pressure waves outside the driver enclosure. The suspension surrounds and suspends the SRS within the enclosure and allows it to vibrate axially. Each of these moving parts, however, have natural structural resonances that can be excited at certain frequencies, which may be different from one another. As a result, at certain frequencies the suspension member moves out of phase, or the SRS itself may move non-pistonically (so-called "break up frequencies". Such out of phase movements can result in an undesirable sound pressure output (i.e. drop or peak in pressure) at these resonant frequencies. In addition, the voice coil may generate a heat output that can cause a distortion in the acoustic output if not dissipated.

Unibody diaphragm and former for a speaker