Elongate, composite-material, hollow rebar structure, along with associated components, related fabrication apparatus, and apparatus-implemented, rebar-structure-making methodology. The rebar structure has a long axis, and includes (a) an elongate, hollow core centered on that long axis, (b) an elongate, hollow sleeve having inner and outer surfaces, circumsurrounding the core along the core's length, with the sleeve's inner surface bonded to the core's outer surface along the length thereof, and (c) longitudinally distributed, radial-dimensionality, external-purchase-enhancing structure formed unitarily with the sleeve's outer surface along the length thereof. The bond existing between the core and the sleeve takes the form of a single-cure, reverse-temperature-gradient-cure, plastic-material, molecular bond.

This invention pertains (a) to hollow, composite-material, rebar structure, also referred to as hollow, composite, core/sleeve rebar structure, and as well (b) to methodology for making this structure, (c) to apparatus which implements the making methodology, and (d) to a system employing the invented rebar structure, and featuring various rebar-to-rebar coupler (or coupling), and other specialized fitting, components.
In particular, and with respect to the just-mentioned, core/sleeve rebar structure, per se, the invention focuses upon a unique arrangement which includes (a) a central, circularly cylindrical, elongate, hollow core formed by pultrusion (in a pultrusion die) from a thermoset plastic resin (preferably urethane-modified vinyl ester) which embeds a plurality of elongate, substantially linear, long-axis-tension-carrying-capable, reinforcing fibers, preferably made of e-glass, and (b) a jacketing, i.e., circumsurrounding, specially, molecularly-joined, circularly cylindrical, elongate, hollow, thermoset plastic-resin sleeve that is formed, in a rotational, transfer-molding die, preferably employing the same thermoset-plastic, urethane-modified vinyl ester resin (or another, compatible thermoset resin material) which is used in the core, and which jacketing resin embeds a plurality of randomly distributed, randomly oriented, "chopped" (i.e., short, typically 1/32-½-inches) reinforcing fibers, preferably made of carbon or basalt. The sleeve material, in particular, preferably takes the form of conventional, i.e., well-known, bulk-molding-compound (BMC) material which has the character just generally described, and which has been found to be well suited for the sleeve portion of the invention. This sleeve, in an operative, structural-incorporation setting for the overall rebar structure in a body, or mass, of surrounding concrete, via the included, multi-directionally oriented, short fibers, responds, as it seems, "multidirectionally", by "gathering" the surrounding environmental, concrete-borne forces and directing them effectively into the long, linear, axially extending, tension-capable fibers present in the hollow core.
Created integrally with and as a part homogeneously of the preferred, BMC-material sleeve, on and along its outside surface, is an outwardly radially projecting, "purchase-enhancing", elongate ridge structure in the form, preferably, of continuous elongate, double-helix winds which, under circumstances with the completed rebar structure viewed in side elevation, present the appearance of evenly spaced screw threads. Other forms of purchase-enhancing structure may, of course, be employed, if desired.
Lying in the background of, and furnishing an underpinning basis for, the creation and development of the present hollow, composite-material rebar invention are certain comparative-advantage, and also difficulty, issues that have been, and that continue to be, experienced differentially in the conventional, predecessor fields involving both long-standing, traditional steel rebar, and more recently, solid, composite, or composite-material, rebar. Steel rebar has, of course, been utilized in infrastructure-reinforcing settings for decades, and solid, composite rebar has now been available and in similar use, for example in the United States, for many (but fewer) years. Solid, composite rebar's generally successful use in various projects implemented during these later years in various types of infrastructure installations has led to its approval for use now in a variety of concrete structures, and the present invention is squarely aimed at offering significantly improved, composite-material rebar structures that enhance its utility in this field.
As those knowledgeable in the art are aware, solid, composite rebar, now conventionally available, offers a number of advantages (with only a few drawbacks) over conventional steel rebar. Non-exhaustively expressed, these advantages include (a) longer-life tolerance against functional and structural degradation—degradation relating to interactive presence in certain environmental, concrete-surround conditions, (b) avoidance of induced proximity damage to surrounding, contacting concrete, (c) low negative impact (resulting from (b)) on the "outside" environment (explained below), and (d) materials-handling, etc. cost savings.
Regarding such advantages, while composite rebar use, in comparison with steel rebar use, in typical concrete infrastructure applications, such as in roads, bridges, tunnels, airport runways, levies and parking decks, clearly offers the benefit of lower transportation and material-handling costs due to the fact that composite rebar material is only about one-quarter the weight of equivalent-diameter steel, its main economic appeal, associated with others of the above-stated advantages, is its ability, through avoiding structural degradation, dramatically to extend the life of a concrete structure in which it has been incorporated. More specifically, concrete structures that are built with steel rebar (either plain or epoxy coated) ultimately fail, and sometimes catastrophically, due to surrounding-environment-induced corrosion of the included rebar. As such rebar corrodes, it not only weakens and loses reinforcement capability, but more seriously, it expands substantially, and essentially "blows apart" the surrounding concrete mass (an event commonly known as spalling concrete, or crumbling infrastructure). "Mending" of such "from the inside" structural damage is typically neither simple nor inexpensive. Rather, repair usually dictates the need for complete structural replacement.
Composite rebar does not cause this kind of problem.
This "does not cause" statement can fairly be made even though there are certain "composite rebar" circumstances wherein some rebar degradation may occur, typically via slow, progressive, alkaline damage to "unshielded glass fibers" often employed as embedded, reinforcing inclusions in concrete-containing composite rebar. Such damage, however, does not produce the dramatically disruptive "blow-apart" phenomenon mentioned above associated with decaying, concrete-held, steel rebar.
Composite rebar use therefore provides a dramatic, and strikingly measurable, advantage when compared to steel rebar use in concrete construction; and while that advantage is, as just outlined, primarily a cost saving advantage due to the extended life consideration for a utilizing project, there is another substantial, and related, benefit which involves an important environmental consideration.
Concrete is perhaps the most ubiquitous building material in the world. It works well, is relatively inexpensive, and is readily available. When a structure fails, as just above described, due to corroding steel rebar, replacement structure must be created with new concrete for the reason that the cement component in concrete cannot be recycled. With this in mind, and recognizing that cement-making, as an industry, generates, and releases into the atmosphere, a significantly high contribution of CO2, minimizing concrete usage as much as possible is a very real concern and intention. It will, accordingly, be evident that the use of composite, instead of steel, rebar in concrete structures successfully addresses this concern by deferring, or even eliminating, the need to replace old rebar-reinforced concrete with new.
While, therefore, solid, composite rebar thus distinguishes itself favorably and advantageously in many ways over traditional steel rebar, it also, as was briefly suggested above, exhibits certain drawbacks that result principally due to its "solidness"—limitations which, importantly, are now successfully addressed by the features of the present, "hollow", two-main-component core/sleeve, composite rebar invention, shortly to be more fully discussed. Notable among the recognized limitations of solid rebar is the so-called "size effect", or "shear lag", issue which becomes evident as the overall outside diameter of such a rebar is increased in the context of offering, or so it is hoped, "more robust" rebar reinforcement in certain applications. The terms "size effect" and "shear lag" will hereinafter be employed interchangeably. Such a rebar diameter increase, unfortunately, and as is well understood by those skilled in the art, causes the core region of a conventional solid, composite rebar progressively to lose core-area efficiency in terms of strength and load handling due to early, differential catastrophic failures that occur in the outer core-reinforcing fibers. Moreover, as the diameter size of traditional, solid, composite rebar increases, so also do the attendant, material-volume usage, and the associated, material-end-product cost. Thus, the "shear-lag" problem confronts traditional composite rebar-usage designers with the dilemma that an increase in rebar diameter size to achieve hoped-for greater reinforcing strength leads to the combined negative effects of (a) an actual, non-proportional (i.e., less than directly following) core-strength increase, and (b), increased material usage and cost.
As will become apparent, the hollow, composite-material, core/sleeve rebar structure which is proposed by the present invention, while retaining all of the important advantages offered by conventional, solid, composite rebar, both significantly addresses, correctively, the solid rebar limitations just mentioned, and at the same time introduces important additional advantages.
The apparatus offered and employed by the invention to make the proposed new hollow rebar structure, and the associated making methodology, collaboratively contribute significantly to the enhanced structural and performance capabilities of the subject, invented rebar structure.
Additionally, the systemic features of the invention which center on employment of the invented hollow rebar structure offer a number of impressive infrastructure installation and use advantages of the invention in a structural concrete mass.
More elaborations about these new features and advantages are presented now immediately below in the respective summary descriptions of the several principal facet-aspects of the invention, as well as later on in the detailed description of the invention.
Hollow, Composite, Core/Sleeve Rebar Structure
According to a preferred and best-mode embodiment of the invention, what is proposed, from a structural, product point of view, is an elongate, composite-material (thermoset plastic and elongate, liner, reinforcing fibers), hollow rebar structure having a long axis, and including, (a) an elongate, hollow, pultrusion-die-formed core centered on that axis and possessing an outer surface, (b) an elongate, hollow, rotationally-transfer-die-molded sleeve having inner and outer surfaces, circumsurrounding, and bonded via its inner surface to, the core's outer surface along the core's length, and (c) longitudinally distributed, radial-dimensionality, external-purchase-enhancing structure formed unitarily and homogenously, in the same rotational transfer-molding process employed for the sleeve, with and along the length of the sleeve's outer surface. Preferably, though not necessarily, the core and sleeve are circularly cylindrical, and the purchase-enhancing structure takes the form of a pair of elongate, continuous, double-helical winds projecting radially outwardly from and along the sleeve's outer surface. It is this condition of radial, outward projection of the helical winds, relative to the outer surface of the sleeve body, which is what is meant by the phrase "radial-dimensionality".
Rebar hollowness, and the setting of the bonded, core/sleeve combination which centrally defines the rebar structure of the present invention, collaborate to offer some surprising and significant performance advantages over all known rebar structures, including certain unique load managing and handling advantages.
Importantly, the bond existing between the core and sleeve, according to preference, takes the form of a single-cure, dual-plastic-material (formed combinationally by that plastic resin material present in the core and that also present in the sleeve), molecular bond, and in a more particular sense, what is referred to herein as a dual-plastic-material, reverse-temperature-gradient-cure, molecular bond —a bond which has resulted from a single, plastic-curing procedure driven by an appropriate temperature gradient defined (a) by a higher temperature created and existing in the central, hollow interior of the core within the rotational transfer-molding die which homogeneously forms the sleeve and the purchase-enhancing structure, and (b) by a suitably lower temperature created immediately outside the core-circumsurrounding sleeve through the wall of the rotational transfer-molding die.
An assisting, and optionally additional, mechanical bond, based chiefly upon appropriate, pre-bonding surface roughening of the outer surface of the pultrusion-formed central core, may also be employed.
In the proposed, preferred-embodiment rebar structure, the core is formed of a thermoset-plastic-resin-containing embedded, elongate, continuous, reinforcing fibers, preferably e-glass, and the sleeve and the purchase-enhancing structure are formed, as mentioned above, of a compatible, thermoset-plastic-resin which contains embedded, randomly-ordered, chopped (short), reinforcing, and preferably carbon fibers. The preferred sleeve material, generally speaking, takes the conventional form of what is known as bulk-molding-compound (BMC) material, wherein the included, chopped fibers, in accordance with the present invention, are made of at least one of carbon (preferred) and basalt. BMC also variously contains other well-known ingredients, conventionally included, and is not therefore discussed in any greater detail herein. We recognize that those skilled in the relevant art will readily choose an appropriate, specific BMC mix, or blend, to invoke their implementations of the present invention.
A proposed, modified form of the rebar structure of the invention, illustrated and discussed herein, is describable as being an elongate, hybrid, rebar structure having a long axis, and including an elongate, composite-material, hollow core featuring (a) a hollow interior centered on that axis, and an outer surface, (b) an elongate rigidifier (such as a steel bar) load-bearingly and cooperatively received within the core's hollow interior, and (c) an elongate, composite-material, hollow sleeve having inner and outer surfaces, circumsurrounding the core along the core's length, with the sleeve's inner surface bonded to the core's outer surface along the length of the latter.
The sleeve, per se, in the rebar structure of the invention is independently expressible as being a jacketing structure for an elongate, hollow-rebar, central core having a long, core axis, with the sleeve possessing (1) an elongate, hollow body formed with a long axis, (2) a hollow interior (in its body) which is adapted to receive, bondedly, such a core in a manner wherein the two, mentioned long axes are substantially coincident, and (3) an outside surface on the sleeve body which includes, distributed along its length, unitarily formed, longitudinally distributed and extending, radial-dimensionality, external-purchase-enhancing structure.
The proposed rebar structure essentially offers all of the advantages of conventional, solid, composite rebar over steel rebar, as mentioned above, while at the same time (a) avoiding the drawbacks which have been associated with such predecessor composite rebar, and in fact (b), introducing several new advantages over all known, conventional rebar structures.
For reasons not completely understood, and which have surprised us, it turns out to be a fact that the overall rebar structure of the present invention, and which is hollow, both in its core, and in its included, core-circumsurrounding sleeve, turns out substantially to avoid, or at least greatly to minimize, the negative "size effect" issue which is presented by solid, composite rebar structure. The central core which, as mentioned, includes elongate generally linear embedded (preferably e-glass) fibers has been found to provide superior tensile load-handling characteristics without any appreciable introduction of a "size effect" problem. These fibers, of course, extending as they do along the long axis of the core, are oriented most appropriately for handling expected high tensile loads when the rebar structure of the invention is placed in operative condition within a surrounding mass of concrete.
The surrounding sleeve, which includes short-length, randomly oriented and distributed fibers of a different material character (preferably carbon, or alternatively basalt), and which typically (in use) resides within the alkaline environment of surrounding concrete, does not exhibit fiber degradation on account of that environment; and, because of its circumsurrounding and jacketing disposition with respect to the inner hollow core to which it is bonded, guards that core, and specifically the preferred e-glass fibers in that core, against degradation-producing exposure to direct contact with the surrounding alkaline "world" of concrete. Additionally, the random-orientations of the short fibers which characterize the construction of the core-jacketing sleeve function extremely effectively, and surprisingly, as we have learned, in private and confidential testing, to "gather" and direct into the linearly extending elongate fibers in the core, the various appropriate vector components of forces which develop in a surrounding mass of load-bearing concrete.
The fact that the proposed hollow rebar structure effectively is made up of two, principal tubular components —components which differ from one another chiefly in the nature of the material used in the included reinforcing fibers—thus characterizes a combined, overall structure which not only survives well within an alkaline, concrete environment wherein it is employed, but also uniquely functions both (a) to gather, and transmit (via multi-directionally oriented fibers) very effectively into the central core, surrounding forces so as to produce noticeably superior tensile load handling (via elongate, substantially parallel linear fibers) within the core, and (b) to do this in a setting wherein "size effect" difficulties that are associated with "differently sized and different-strength" rebar structures have not appreciably materialized. The differential-material characters of the fibers in the sleeve and the core produce a "best of many worlds" behavior for the proposed rebar structure, with the included fibers in each of these two, collaborating structural components functioning most appropriately in their respective "rebar settings".
In connection with the just-mentioned, important, "different-strength", non-problematic "size effect" consideration, an extremely interesting feature of the hollow rebar structure of present invention is that, while various outside, overall sleeve diameters may be created effectively to furnish a range of nominal, staged-strength rebar sizes, it turns out to be the case that for a given rebar structure with a particular outside sleeve diameter, merely by changing alone the wall thickness of the internal core, an interesting range of differed rebar strength sizes is attainable. Not only is this feature of the invention by itself interesting, beyond this "rebar-internal" feature, within a given structural-use environment involving a particular, set-outside-dimension mass of concrete, and without in any way diminishing, or otherwise altering, the volume (the internal content) of that mass (which possesses its own pre-design, load-carrying capacity) to accommodate differences in the outer diameter of intended, embedded reinforcing rebar structure, simply by changing wall thickness of the included, inside, tubular core in the rebar structure of the present invention, there are available different, rebar-strength-reinforcement choices for such a concrete mass.
Put another way, the present invention, by allowing for effective rebar strength changes simply through changing wall thickness in the included inside core, without changing outside diameter dimensions of the sleeve, effectively makes the changing of rebar "strength sizes" independent of surrounding, pre-design mass dimensions of concrete. In this context, one will note that, with conventional solid, composite, or steel, rebar structure, and for a given-outside-dimension mass of concrete, a diameter change in the outside dimensions of such rebar structure automatically requires a change in the surrounding volume of the, pre-dimension-determined, given mass of concrete, with more concrete being employed with smaller-diameter rebar structures and less concrete being employed to accommodate larger-diameter rebar structures. This, of course, is a situation in which surrounding concrete mass, for a given, desired, set of outside dimensions, is not independent of rebar "size strength".
Another feature of the hollow rebar structure of the present invention is that it offers, for useful and innovative employment, the internal, hollow, central channel for the "routing", for example, of various kinds of infrastructure possibilities like cabling or fluid conveyance (such as for controlling anti-freezing of bridge surfaces), as well as the selective introduction of protected (i.e., shielded), additional strengthening elements, such as inserted steel bars, if desired. Additional creative use of the hollow aspect of the rebar structure of the present invention might include the installation therein of various types of information-generating sensors to improve utilization of a rebar-reinforced structure, for example for optimizing traffic flow on bridges, for monitoring use-history in order to schedule maintenance more effectively, for monitoring load management, and for other things.
Rebar-Making Methodology
From one methodologic point of view, the methodology of the invention may be expressed as a method of making an elongate, composite-material, hollow rebar structure including the steps of (a) forming an elongate, composite-material, hollow core, (b) in association with such forming, preparing along the core's length an elongate, composite-material, core-circumsurrounding, hollow sleeve having inner and outer surfaces, (c) in association with such preparing, creating, unitarily with the sleeve, and in a manner distributed along the length of the sleeve's outer surface, an external-purchase-enhancing structure possessing radial-dimensionality, and specifically in the form of a pair of elongate, continuous, generally helically paralleling winds extending along the length of the sleeve's outer surface, and (d) bonding the inner surface of the sleeve to the outer surface of the core. Preferably, this methodology is carried out in manners whereby the core-forming step is performed by pultrusion, and the preparing and creating steps are implemented by continuous transfer-molding within a rotational die.
In this methodology, bonding is implemented preferably in a manner which establishes between the core and sleeve a bond in the form of a single-cure, dual-plastic-material molecular bond, and in the more particular sense expressed above herein, what is referred to herein as a dual-plastic-material, reverse-temperature-gradient-cure bond as generally described. Such a bond, and particularly the reverse-temperature gradient, single-cure aspects of it, play(s) an important role in the performance of the present invention in many applications.
As mentioned also above, a mechanical bond may be implemented.
From another point of view the invention methodology may be described as a method of making an elongate, composite, hollow rebar structure featuring (a) forming, in a pultrusion die, an elongate, composite-material, fiber-reinforced, curable-plastic-material-including, hollow core, (b) applying heat within the pultrusion die to create, for the core's included plastic material as it emerges from the die, an outer-surface plastic condition which is less than 100% cured, (c) in association with, and downstream from, the forming step, preparing, in a rotational, continuous-transfer-molding die, on the less-than-100%-cured, outer-surface plastic of the emerging core and along its length, an elongate, hollow, composite-material, fiber-reinforced, curable-plastic-material-including, core-circumsurrounding sleeve, (d) in relation to such preparing, and within the transfer-molding die, creating, unitarily with the sleeve, and in a manner distributed along the length of the sleeve's outer surface, an external-purchase-enhancing structure possessing radial-dimensionality, and (e) within the transfer-molding die, applying heat to effect between the plastic material in the core and that in the sleeve a single, reverse-temperature-gradient-cure, plastic-material bond.
The unique, two-component, core/sleeve structure of the present invention is especially accommodated by, and in relation to, the just-above-outlined methodology of the invention which involves the under-curing of plastic resin material during the core-forming pultrusion process—an under curing procedure referred to as B-staging which assures that, as the formed core emerges from the pultrusion-forming die, the surface condition of the resin in that core has enough of a temporarily-lasting, under-cured condition so that subsequent bonding, as will later be explained herein, with the inner surface of the about-to-be-downstream-formed sleeve takes place in a very robust manner.
Other manners of characterizing the methodology of the invention will become apparent in the detailed description of the invention presented later herein.
Apparatus for Implementing Methodology
The present invention, as mentioned above, also proposes special apparatus for carrying out the methodology of the invention in order to produce the rebar structure of the invention.
Thus, it offers apparatus for making an elongate, composite-material, hollow rebar structure, such apparatus having a long, rebar-formation axis, and upstream and downstream regions disposed at spaced locations on and along that axis. The proposed apparatus, progressing therein, and therealong, from the upstream region toward the downstream region, includes (1) an elongate, hollow mandrel having a long axis which is substantially coincident with the rebar-formation axis, extending from adjacent the upstream region toward adjacent the downstream region, (2) an elongate, hollow pultrusion die disposed operatively adjacent the upstream region, having a long axis which is substantially coincident with the rebar-formation axis, circumsurrounding the mandrel, and operable to form an elongate, composite-material, hollow core in the region disposed between itself and the mandrel, and (3) an elongate, hollow, transfer-molding die disposed downstream, and spaced, from the pultrusion die, having a long axis about which it is rotatable and which is substantially coincident with the rebar-formation axis, the transfer-molding die being operable to form, along the length of a core which has been formed upstream by the pultrusion die, (a) an elongate, composite-material, core-circumsurrounding, hollow sleeve having an outer surface, and (b), unitarily with the sleeve, and in a manner distributed along the length of the sleeve's outer surface, an external-purchase-enhancing structure possessing radial-dimensionality.
The apparatus of the invention, as just generally described, further includes plural heaters distributed in spaced relation with respect to one another along the rebar-formation axis, and disposed in operative adjacency relative to, and association with, the pultrusion and transfer-molding dies. These heaters uniquely feature special, internal heating structure which is disposed within the above mentioned hollow mandrel where it extends through and within the transfer-molding die—this internal heater being operable to produce a "reverse", radially outwardly directed (relative to the rebar-formation axis) heat gradient.
The importance of this feature in creating a robust core-sleeve bond has been mentioned above.
Additionally included in the apparatus of the invention is a power-driven puller disposed downstream along the rebar-formation axis in spaced relation to the transfer-molding die, operable to pull a forming rebar through the dies in a downstream direction along the rebar-formation axis under the influence of a drive motor. This drive motor operates the puller at a speed which moves a forming rebar along the rebar-formation axis at a rate relative to the pultrusion die and to the heaters which are operatively associated with that die whereby the outer surface of plastic material in core structure emerging downstream out of the pultrusion die, and later entering the transfer-molding die, is, and remains during transit between the dies, in a less-then-100% cured condition.
Hollow, Composite-Rebar Systemic Features
The present invention, in addition to all of the above, further proposes a system expressible as including (a) first and second, elongate, hollow-interior, composite-material rebar elements having ends, and (b) a composite-material coupler disposed between, anchored to, and joining a pair of adjacent ends in these elements. These system elements have respective long axes, and the coupler orients these element axes in a condition of nonalignment relative to one another.
In a more particular sense, the hollow interiors of the elements communicate with the elements' ends which are open, and the coupler is elongate, and possesses along its length a double-open-ended hollow interior which communicates with the hollow interiors in the elements. The coupler is anchored to the elements via receiving, or being inserted into, the elements' ends.
From another systemic perspective, the invention may be described as a composite-material rebar system which includes an elongate, composite-material rebar element, and a defined-function fitting joined to that element. Fittings proposed include angular rebar joiners (couplers), plugs, T-type rebar links, and many others described below herein. Fittings may be positionally-adjustably joined to system rebar elements.
These and various other features and advantages of, and offered, the present invention will become more fully apparent as the detailed description of it below is read in conjunction with the accompanying drawings and the appended claims.
Various components, structures and component arrangements (dispositions) that are shown in these drawing figures are not necessarily drawn with precision accuracy, or to scale with respect to one another.

Hollow, composite-material rebar structure, associated components, and fabrication apparatus and methodology


A method of determining at least one optical property of a projection exposure system is described, wherein the exposure system includes a beam delivery system having a light source for generating an exposure optical beam having light of a first wavelength (λ1) and a second wavelength (λ2), wherein a first ratio is defined as an intensity of light λ2 to an intensity of light λ1 in the exposure optical beam. The method includes supplying at least one measuring optical beam including light of at least λ1 to the projection optical system, detecting wavefronts having traversed the projection optical system, and determining an optical property in dependence of the detected wavefronts, wherein a second ratio of an intensity of light of λ2 to an intensity of light of λ1 in the measuring optical beam being incident on the detector of the wavefront detection system is less than the first ratio.

1. Field of the Invention
The present invention generally relates to a method of determining optical properties in a projection exposure system and a projection exposure system comprising a wavefront detection system. In particular, the present invention relates to the determination of optical parameters from one or more wavefronts in a projection exposure system wherein light of more than one wavelength is used for exposure.
2. Brief Description of Related Art
Lithographic processes are commonly used in the manufacture of semiconductor elements, such as integrated circuits (ICs), LSIs, liquid crystal elements, micropatterned members and micromechanical components.
A projection exposure apparatus used for photolithography generally comprises an illumination optical system with a light source and a projection optical system. Light from the illumination optical system illuminates a reticle (mask) having a given pattern and the projection optical system transfers an image of the reticle pattern onto a photo-sensitive substrate. The image of the reticle pattern may also be reduced in size by the projection optical system so as to produce a smaller image of the reticle pattern on the substrate.
The trend towards ever more sophisticated semiconductor devices requires semiconductor elements of smaller size and higher complexity which, in turn, makes higher demands on the optical performance achievable with projection exposure systems. In particular, the image of the reticle pattern needs to be very accurately projected onto the substrate. Therefore, for instance, aberrations of the wavefronts of the light transferring the image of the reticle pattern onto the substrate need be to reduced to the greatest extent possible.
Various methods and systems are known which allow to alter the optical performance of the projection exposure systems after assembly of the various components comprised in the projection exposure system. For instance, one or more lenses can be tilted or moved along an optical axis of the system to reduce certain types of aberrations, such as astigmatism. After assembly and optimisation, the optical performance of a projection exposure system may undergo a change induced by a variation in atmospheric conditions of the environment the projection exposure system is exposed to, for example. The optical performance of the projection exposure system may also change over time.
In order to be able to optimise the optical performance of a projection exposure system and make adjustment(s) thereto, optical properties of the projection optical system need to be accurately determined.
Various methods of determining optical properties in a projection exposure system and detection systems for detecting these properties are known. Amongst those, the most preferable are those which allow for in-situ measurements of the optical properties in the projection exposure system and do not require significant alteration of the projection exposure system. In-situ measurements thus increase ease of use and time-efficiency of the projection exposure system.
Among the commonly employed wavefront detecting techniques is the Shack-Hartmann-technique. This technique involves splitting a wavefront in a pupil plane of the projection optical system into a plurality of portions and measuring a gradient of each split wavefront portion. Thus, an aberration of the split portion and an aberration of the whole wavefront can be determined. An example of a wavefront detecting method using the Shack-Hartmann-technique is described in US 2002/0159048 A1, for instance, the entire content of which is incorporated by reference herein. Alternatively, the classical Hartmann test technique may be used for measuring wavefront profiles.
Other wavefront detection methods known in the art are based on interferometric techniques. Point diffraction interferometry, Twyman-Green interferometry, Fizeau interferometry, or shearing interferometry methods may be used, for instance.
U.S. Pat. No. 5,828,455, the entire content of which is included by reference herein, describes a method and apparatus for analysing a wavefront at a multiplicity of field points over an entire lens train. The method is based on the finding that upon irradiating a reticle, spots are created at an image plane of the projection optical system which are deviated from their diffraction-limited positions, which deviation can be measured. The method includes using an aperture plate consisting of a multiplicity of openings with each opening being centred underneath a neighbourhood of points accepted into an entrance pupil of an imaging objective. Points traversing through all openings will produce a number of spot arrays in a substrate plane. The totality of all the arrays of spots whose centroids can be measured and reconstructed yields an aberrated wavefront at a number of discrete field points. Thus, an in-situ interferometric analysis of a wavefront having traversed the projection optical system in a projection exposure system is provided.
In US 2002/0001088 A1 a method and apparatus for detecting wavefronts by shearing interferometry are disclosed, the entire content of which is incorporated by reference herein.
U.S. Pat. No. 6,344,898 discloses a point diffraction interferometer for measuring a test surface by detecting the state of interference fringes generated by interference of a reference light beam that interacts with the test surface. The reference and measurement beams are produced by a point light source. In WO 02/42728, a method and apparatus for measuring an aberration of a projection optical system are described which are based on point diffraction interferometry. The entire contents of both referenced documents are incorporated herein by reference.
Wavefront detection techniques for in-situ determination of optical properties require a wavefront source and, hence, a light source. Generally, for reasons of ease of use, a beam generated by the light source comprised in the projection exposure system will be used both in an exposure mode for exposing a substrate and a measurement mode for detecting a wavefront and determining optical properties in the projection optical system.
With projection exposure systems being developed for ever smaller wavelengths, among the light sources currently used or being envisaged for use are excimer lasers such as ArF lasers (193 nm) and KrF lasers (248 nm) as well as F2-lasers (157 nm), which emit light in the ultraviolet range. In addition, the development goes towards use of light sources emitting light in the extreme ultraviolet end (EUV) of the spectrum, such as plasma sources.
The range of wavelengths of light emitted by the various light sources differs largely. While lasers are usually adapted to emit substantially monochromatic light, i.e. emit light of one wavelength having a small spectral bandwidth, plasma sources used in EUV projection exposure systems tend to emit a broad band of wavelengths. In view of the requirements of the projection exposure system in terms of accurate projection of an image of the reticle pattern onto the substrate, the light source will have to fulfil certain specifications in terms of feasible spectral bandwidths and wavelengths.
However, whilst the transition to smaller wavelengths has been well accommodated in terms of a quality achievable in an exposure mode, results from wavefront detection techniques measuring at the wavelength of exposure have been found to be unsatisfactory.

Method of determining optical properties and projection exposure system comprising a wavefront detection system


A first terminal for use in a time division duplex communication system comprising apparatus for automatically, successively, repetitively and alternatingly transmitting and receiving compressed signals to and from another terminal via a single transmit and receive time divided channel, including apparatus for changing a transmit and receive mode of the first terminal in synchronism with an opposite transmit and receive mode of another terminal, apparatus for receiving a timing signal which is the same timing signal received by another terminal, and apparatus for changing the mode at intervals determined from reception of the timing signal.

Conventional telephone systems operate in full duplex mode. This means that both parties linked by the telephones can speak at the same time. Many radio systems operate in a mode known as half duplex mode which means that only person at an end can talk at a time. The direction of the communication is controlled by a "press to talk button" which is activated by the party wishing to speak. In order to avoid confusion, the party that is talking must indicate verbally that the user is relinquishing the channel by saying "over". Examples of such systems include air to ground radios, HF radios and many portable radio systems. The reason for the popularity of half duplex despite its inconvenience is that it uses only one frequency, an important consideration where frequencies are at a premium. One disadvantage of a manually controlled half duplex communications system is that it is difficult to interface a half duplex radio system to a conventional telephone. In addition, normal conversation which allows one party to interrupt the other is impeded by the press to talk operation. This is especially annoying for persons accustomed to the normal telephone system which is full duplex.
A channel which has only sufficient capacity to carry voice information in one direction generally cannot be used to provide a two way voice link simultaneously.
Full duplex can be achieved if the two ends of the link operate in what is known as Time Division Duplex (TDD) mode. The channel is allocated 50 percent of the time to transmit information in each of the two directions. That is, the radio channel is divided into time slots of T/2 seconds, each end transmitting in alternate time slots. When one end is transmitting, the opposite end is receiving the information. In this way one frequency can be used for information flow in both directions resulting in a full duplex link.
One such system is the cordless telephone system known as CT2 in which the voice is digitized by an ADPCM codec to 32 kbits/sec. The transmission rate of the data through the radio channel is about 64 kbits/sec, so that in each T/2 second time slot 64 kbits of information are transmitted in each direction. In addition some additional bits are introduced into the data to accommodate synchronization and other "house keeping" information needed to keep the timing between the two ends of the link aligned. The data received within the T/2 time slot at 64 kbits/sec is expanded to form a uniform 32 kbit/sec bit stream after house keeping information is stripped off, and is applied to the codec to be converted to voice. For the TDD system to work the channel must be capable of carrying more than twice the data rate needed for one voice codec.
For systems such as HF radio, and VHF AM radios used for air traffic control the maximum rate that can be carried reliably within the assigned band is not sufficient for transmission of voice using time division duplex as described in the previous paragraph with the present state of the speech coding and data transmission technology. For example, HF radios have the capability to carry data reliably at 2.4 Kbits/sec and a codec which can encode high quality voice at 1.2 kbits/sec does not presently exist.
A system which allows a full duplex voice communication such as a telephone conversation over the same narrow-band radio channel uses time compression of the voice signal and analog time division multiplex of the channel, is described in U.S. Pat. No. 5,355,363 dated Oct. 11, 1994, invented by Takahashi et al. In that system, a segment of analog voice with duration T seconds is converted into a segment of analog signal with duration T/2 seconds. The encoded version of the (analog) voice signal occupies a bandwidth which meets the requirements of the regulatory bodies, so but in order to contain the signal with the channel, at least half of the voice bandwidth is eliminated. This substantially degrades the fidelity of the signal.
In the system described in the patent, the transmit and receive timing for the channel is determined by a synchronization signal that is transmitted in the same channel the analog signal, which of course limits the channel time, restricting further the frequencies of the signal that can be transmitted, and the resulting fidelity of the voice signal.

TDD communication system which receives timing signals from a satellite and automatically, successively, repetitively, and alternatingly transmits and receives compressed signals in a single channel

Her Majesty the Queen in Right of Canada as represented by the Minister of Communications


An apparatus dynamically changes a connection service category for a soft permanent virtual circuit (SPVC). The apparatus includes a first interface, a second interface, a control interface receiving a command including a new connection service category for an exiting SPVC, and a module responsive to the command. The SPVC includes a permanent virtual circuit (PVC) connection leg set up from a source end to the first interface, and a switched virtual circuit (SVC) connection leg set up from the second interface to a destination-end via a communications network. The module releases the SVC connection leg while maintaining the PVC connection leg, de-allocates resources from the PVC connection leg, allocates new resources corresponding to the new connection service category and traffic parameters on the PVC connection leg, and creates a new SVC connection leg in accordance with the new connection service category and the traffic parameters.

FIG. 1 schematically illustrates a typical Soft Permanent Virtual Circuit (SPVC) 10 which includes a Permanent Virtual Circuit (PVC) connection leg 12 and a Switched Virtual Circuit (SVC) connection leg 14. For example, as shown in FIG. 1, the PVC connection leg 12 is set up from an edge router 16 to a network switch 18, and the SVC connection leg 14 is set up from the network switch 18 to another network switch 20 via a communications network 22. The SVC connection leg 14 may be set up inside a Service Provider network. As shown in FIG. 1, the network switch 20 may be an destination end device, or may be coupled to a destination device (router) 24.
An SVC is dynamically established on demand and is torn down when transmission is complete. SVCs are also referred to as Switched Virtual Connections in Asynchronous Transfer Mode (ATM) terminology. An SPVC allows devices (for example, the routers 16 and 24 in FIG. 1) attached to the network switches to be interconnected via virtual circuits which will be automatically rerouted around failures in the communications network. For example, as shown in FIG. 1, an SVC is dynamically created, using link A or link B. If either link fails, the SVC is automatically reestablished using the other link.
On the other hand, a PVC must be explicitly configured using a specific link, for example, either link A or link B in FIG. 1, and all network devices (switches and/or routers) along the virtual circuit (or path) must be explicitly configured. Each link between the network devices is also individually identified using a connection identifier, for example, virtual channel identifier (VCI) and virtual path identifier (VPI) defined at the interfaces of the network devices. In an ATM cell header, the VCI and VPI are a 16-bit field and a 8-bit field, respectively. In PVCs, the VCI and the VPI are used to identify the next destination of a cell as it passes through a series of ATM switches on its way to its destination. ATM switches use the VPI/VCI fields to identify the next network virtual channel link (VCL) that a cell needs to transit on its way to its final destination.
In a Frame Relay (FR) network, a data-link connection identifier (DLCI) is used. A value of the DLCI specifies a PVC or an SVC in a similar manner as the VPI and VCI. In the basic FR specification, DLCIs are locally significant (connected devices might use different values to specify the same connection). However, in the Local Management Interface (LMI) extended specification, DLCIs are globally significant and DLCIs specify individual end devices.
A connection service category is associated with each SPVC connection, which is typically defined by traffic parameters and parameter values per interface. The association between an SPVC connection and its service category is set up at the time of the creation of the connection. If the service category of an existing SPVC connection needs to be changed, a user or system administrator must delete the entire SPVC connection, and then create a new connection for the new service category with the modified/new traffic parameters. That is, both of the PVC and SVC legs must be removed and recreated with new commands using (hopefully) the same VPI/VCI values. However, since there is always a finite delay (SPVC downtime) between an explicit deletion of the existing connection and reconfiguration of a new connection, the VPI/VCI values in the original connection might be used by other circuits during the downtime, and thus the original VPI/VCI values cannot be guaranteed in the new connection. This means that the new connection would lose its identity with the original connection, and would be considered as a completely different connection.
This may pose a problem especially at the edge where the Service Provider may require the Enterprise or connecting router at the edge to change the parameters. The problem becomes complicated, if the connecting router/switch is in a restricted domain such as a Central Office since some legal paperwork may have to be executed for a new connection identified by new VPI/VCI values different form the original values.

This patent is subject to a terminal disclaimer.

Dynamic connection service category changes


A system and computer program product that off-loads the processing associated with responding to user status requests for software task execution queues or for queued software tasks that are managed by a software task manager. A software task manager is periodically queried for status and the results of that periodic query are stored in a file. User queries for the status of the software task manager are handled by a separate process on a separate computing node. Queries submitted by users for the status of queues or queued software tasks managed by the software task manager are satisfied by retrieving the status data that are stored in the file. Alternative embodiments distribute copies of the file to several computing nodes to further alleviate the processing bottleneck caused by responding to frequent task manager status queries from many users.

1. Field of the Invention
The present invention relates to monitoring software tasks that are executing on a computer system, and more specifically to a system and method for allowing users to query the status of executing computer tasks.
2. Description of Related Art
Large computing systems are able to be used by a large number of users that can number into the hundreds and even thousands. These computing systems have software task management facilities that accept software tasks, which are sometimes referred to as "jobs," and that manage the execution of those software tasks. The management of these software tasks can include queuing these jobs with or without prioritization relative to each other and then executing the queued jobs as computing resources become available. These computing systems are sometimes made up of several computers or processors that are interconnected together and that are configured to operate in a manner so as to appear to be a single computer. An example of such a computing system is a computer cluster, where many computers are interconnected using high-speed and dedicated communications links between one another in order to support efficient parallel and/or coordinated operations and processing. Other examples include multiple computers that are interconnected by more conventional communications means, such as computer networks.
The software task management system used by these computer systems allows users to request the status of the execution queues that contain the tasks that are queued for execution on the one or more computers controlled by that software task management system. This software task management system also allows querying of the status of a particular task that is contained within the execution queue. Determining the status of the software task execution queue or of a particular task within the queue is an additional processing burden on the software task management system. The queue of software tasks that are awaiting execution grows as the processors of the computer system become more heavily loaded. The users of such heavily loaded computer systems will request the status of the queued software tasks, as well as the status of the queue itself, in order to determine, or to try to estimate, when their previously submitted software task is likely to execute. Users also query the status of the software task execution queue to determine if it is practical to submit new tasks because the wait for execution may be long.
As the computers become more heavily loaded with submitted software tasks and the queue of software tasks awaiting execution becomes long, the users issue requests for the status of the queue and of their submitted tasks with increasing frequency. Automated software programs that are able to repetitively submit status requests to the software task management system can also be used by the users. In computer systems that support hundreds or thousands of users, satisfying the status requests from all of these users clamoring for the status of the queue and the position of their submitted software tasks within the queue can become a significant burden for the software task management system as well as create a large processing demand for the computer upon which the software task management system is executing. This results in long delays for the return of the requested status for a queue or a queued software task, and additional delay in the execution of tasks as the computing resources used to satisfy these many status requests cannot be used to execute the queued software tasks.
In order to more effectively handle the many status requests submitted to a heavily loaded computer system while minimizing the processing load presented by these status requests, an efficient way to satisfy user queries to a task manager is needed.

Method and system for off-loading user queries to a task manager

International Business Machines Corporation


A pet toy capable of dispensing catnip or similar substance. The toy comprises a compartment for holding the substance. The toy also comprises a movement-promoting element operative to move the compartment so the substance, or an aroma of the substance, may pass through a sifting hole of the compartment. One embodiment of the toy comprises a rotating element, such as a ball, rotating about a horizontal axis within a larger body as a result of propelling the toy across a horizontal surface. The rotating element includes the compartment holding the substance so that some of the substance escapes the compartment as a result of the rotation of the rotating element. Various alternative embodiments of the invention are also described.

1. Technical Field
The invention relates generally to pet toys, and more specifically to a pet toy that dispenses a substance, such as catnip, attractive to the pet.
2. Background Art
Cats are often considered by the misinformed to be aloof, detached creatures that would rather recline on a soft, plush rug than expend energy running about for no apparent purpose. However, those who better understand the true nature of domestic felines realize these very same animals become wild, energetic creatures exhibiting near-manic behavior when provided the proper impetus. Inducing such movement frequently in a cat is generally believed to provide health benefits and increased longevity to the pet, as well as produce emotional enhancement for the owner in the form of laughter.
Most cat owners employ at least one of two different ways of physically energizing their favorite feline companion. For one, many cats enjoy playing with a pet toy of some sort, especially one that exhibits movement. The types of toys that typically elicit a physical reaction from a cat range from simple objects, such as balls of yarn, to more complex devices, such as mechanical toys constructed to move suddenly when a cat makes contact with the toy.
The second way cat owners typically evoke physical exercise from their pet is to provide catnip. Catnip is a strongly aromatic perennial herb long recognized for its capacity to drive cats to a heightened state of activity. Even small amounts are known to drive a cat to distraction.
Given the foregoing, an apparatus combining the aforementioned advantages of a movable toy and catnip or similar substance would be advantageous.


A hearing aid fitting system comprising a computer with fitting software and having a display for displaying parameter settings of a hearing aid and input means for adjustment of the parameters, characterized in that the system further comprises a camera for recording images of the wearer's head including the ear with the hearing aid, and a display for displaying at least one image received from the camera.

Hearing aid fitting systems are well known in the art, e.g. cf. U.S. Pat. No. 5,835,611. Such systems have proven adequate for adjusting signal processing parameters so that the hearing aid accurately compensates the actual hearing loss of the hearing aid wearer.
The fitting process typically involves measuring the auditory characteristics of an individual's hearing, estimating the acoustic characteristics needed to compensate for the particular auditory deficiency measured, adjusting the auditory characteristics of the acoustic hearing aid so that the appropriate acoustic characteristics may be delivered, and verifying that these particular auditory characteristics do compensate for the hearing deficiency found by operating the acoustic hearing aid in conjunction with the individual.
Standard techniques are known for these fittings which are typically performed by an audiologist, hearing aid dispenser, otologist, otolaryngologist, or other doctor or medical specialist.
In the well-known methods of acoustically fitting a hearing aid to an individual, the threshold of the individual's hearing is typically measured using an audiometer, i.e. a calibrated sound stimulus producing device and calibrated headphones. The measurement of the threshold of hearing takes place in a room with very little audible noise.
Generally, the audiometer generates pure tones at various frequencies between 125 Hz and 8,000 Hz. These tones are transmitted to the individual being tested, e.g. through headphones of the audiometer. Normally, the tones are presented in step of an octave or half an octave. The intensity or volume of the pure tones is varied and reduced until the individual can just barely detect the presence of the tone. This intensity threshold is often defined and found as the intensity of which the individual can detect 50% of the tones presented. For each pure tone, this intensity threshold is known as the individual's air conduction threshold of hearing. Although the threshold of hearing is only one element among several that characterizes an individual's hearing loss, it is the predominant measure traditionally used to acoustically fit a hearing aid.
Once the threshold of hearing in each frequency band has been determined, this threshold is used to estimate the amount of amplification, compression, and/or other adjustment that will be employed to compensate for the individual's loss of hearing. The implementation of the amplification, compression, and/or other adjustments and the hearing compensation achieved thereby depends upon the hearing aid being employed. There are various formulas known in the art which have been used to estimate the acoustic parameters based upon the observed threshold of hearing. These include generic rules, such as NAL and POGO, which may be used when fitting hearing aid from most hearing aid manufactures. There are also various proprietary methods used by various hearing aid manufacturers. Additionally, based upon the experience of the person performing the testing and the fitting of the hearing aid to the individual, these various formulas may be adjusted.

Hearing aid fitting system with a camera


Disclosed is a vehicle. The vehicle comprises a first hydraulic pump, a first hydraulic motor, a first axle shaft, a second hydraulic pump, a second hydraulic motor, a second axle shaft, a first bypass, a first linkage, a second bypass and a second linkage. The first hydraulic motor is connected to the first hydraulic pump by a first hydraulic porting. The first axle shaft is driven by the first hydraulic motor. The second hydraulic motor is connected to the second hydraulic pump by a second hydraulic porting. The second axle shaft is driven by the second hydraulic motor. The first bypass is associated with the first hydraulic porting. The first linkage is connected to the first bypass. The second bypass is associated with the second hydraulic porting. The second linkage is connected to the second bypass. The first bypass and the second bypass are actuated substantially simultaneously by a single actuating mechanism.

The description of references in this Section is not intended to constitute an admission that any patent, publication or other information referred to herein is "Prior Art" with respect to the Present Invention, unless specifically designated as such.
Hydrostatic transmission ("HST") systems and transaxles are well known in the industry, and are more fully described in, e.g., U.S. Pat. No. 5,314,387, the contents of which are incorporated herein by reference in its entirety. In general, a typical HST system possesses, inter alia, a hydraulic pump and a hydraulic motor mounted in a housing. The hydraulic pump and hydraulic motor are hydraulically-linked through a generally-closed hydraulic circuit, and both consist of a rotatable body with a plurality of reciprocating pistons mounted therein. A hydraulic fluid, such as oil, is maintained in the generally-closed hydraulic circuit, and the HST generally has a sump, or reservoir, with which the generally-closed hydraulic circuit can exchange oil. In certain instances, this sump may be formed by the housing itself.
The hydraulic pump is usually driven by an external motive source, such as a pulley and belt system or a plurality of drive shafts connected to an internal combustion engine. The reciprocating pistons engage a moveable swash plate and, as the hydraulic pump is rotated by an input source driven by the engine, the reciprocating pistons engage the swash plate. Other HST designs may use a radial piston or ball piston pump and motor design, but the general operation is, in any event, similar, and the Present Invention is not limited to use with a specific design.
Movement of the reciprocating pistons creates movement of the hydraulic fluid from the hydraulic pump to the hydraulic motor, causing the rotation thereof. Motor pistons are engaged against a fixed plate, and rotation of the hydraulic motor drives an output shaft engaged thereto. This output shaft may be linked to mechanical gearing and output axles, which may be internal to the HST housing, as in an integrated hydrostatic transaxle ("IHT"), or external thereto.
Further, the system is fully reversible in a standard HST. This means that, when the swash plate against which the pump pistons move is moved, the rotational direction of the motor can be changed, such as in a forward or reverse direction. In addition, there is a "neutral" position where the pump pistons are not moved in an axial direction, so that rotation of the pump does not create any movement of the hydraulic fluid.
HZTs are also known in the industry. Generally, an HZT is utilized in connection with a vehicle to provide for the independent control of each of the drive wheels of a vehicle. By way of example, HZTs are described in U.S. Pat. Nos. 5,078,222 and 6,775,976, the contents of which are both incorporated herein by reference in their entireties. Generally speaking, the HZTs in the aforementioned references comprise two reduction drives powered by independent self-contained hydraulic power units. Additionally, Eaton has developed and marketed zero-turn transaxles, commonly known as Eaton Models 771 and 781. The Eaton Model 771 is an assembly with one pump and one motor where two Eaton Model 771 HZT assemblies, a right and a left, are required for zero-turn drive. The Eaton Model 781 consists of two units similar to the Eaton Model 771 joined together to make one assembly.
Each of the HZTs described above possesses the generally-closed hydraulic circuit discussed above. Thus, each individual HZT possesses two distinct sides, namely, a high pressure side in which oil is being pumped from the hydraulic pump to the hydraulic motor, and a low pressure, or vacuum, side, in which oil is being returned from the hydraulic motor to the hydraulic pump. When the swash plate angle is reversed, the flow out of the hydraulic pump reverses so that the high pressure side of the circuit "becomes" the vacuum side, and vice versa. This generally-closed hydraulic circuit can be formed as porting within the HZT housing, internal to a center section on which the hydraulic pump and hydraulic motor are rotatably mounted or in other ways known in the industry. Check valves may also be used to draw hydraulic fluid into the low pressure side to make up for fluid lost due to leakage, for example. Such check valves may be located so that they directly contact the porting or they may be located separate from the porting and connected through additional bores to the closed circuit. Additionally, an HZT may be provided with a means by which the closed loop may be opened to the sump or the high and low pressure side connected together. The means is commonly known as a "bypass" or a "bypass circuit."
There is a need to provide a means to open, or bypass, this closed circuit in certain circumstances. This is necessary because when the vehicle is stopped, the oil in the closed circuit provides for hydraulic braking, making it difficult to manually move the vehicle. Mechanical bypass designs are known in the art and are described in, for example, U.S. Pat. No. 5,423,182, the contents of which are incorporated herein by reference in its entirety. Such designs generally achieve bypass by opening the closed hydraulic circuit to the sump by, e.g., opening check valves in the circuit or by opening a shunt between the high pressure and low pressure sides of the circuit. However, due to the nature of HZT configurations, the need exists for an improved bypass linkage assembly that can obtain bypass through the pull of only one handle.

Zero turn hydrostatic transmission bypass linkage


An antenna connector and RF switch assembly (10) is provided on a portable radio (14). The radio includes a self-contained antenna (16) and a radio circuit (27). The assembly (10) is used for selectively connecting the radio circuit (27) to the antenna (16) or to an external signal supply (39). In the assembly, a switchable conductive center contact portion (22, 20, 35) selectively engages either the antenna (16) or the external signal supply (39). A metallic housing (18), having an antenna bushing (17), receives the antenna (16). A molded dielectric insulator portion (26) separates the switchable conductive center contact portion from the metallic housing and is directly connected to the antenna bushing.

It is known in portable radios to provide a receptacle on the radio housing for switchable connection of an integral antenna or external circuits from a remote antenna, to the radio. Such a receptacle connector is described in U.S. Pat. No. 3,946,390. A soldered pigtail connects that receptacle connector to a coaxial connector of the integral antenna. Coaxial connectors are generally used for providing impedance matched and shielded radio frequency (RF) connections. To reduce parts and labor, there exists a need to provide a solderless combination of a coaxial connector and an RF switch in the same device.

Combined coaxial connector and radio frequency switch assembly


A method and apparatus locates edges of patterns in a stored image, such as edges of bars or finder patterns of machine-readable symbols. The present invention first selects an edge point or pixel within a stored image. A dominant direction is determined therefrom by examining a region surrounding the selected point. A smaller window is then examined around the edge point to derive a hexadecimal code based on binary values of pixels which surround the edge point. The hexadecimal code is compared to a table of codes, where each code maps to a similar window and identifies a next edge point. The process continues in the dominant direction until the entire edge is located. Circuitry for rapidly performing the its location of patterns in a stored image, such as ages of bars of finder patterns of machine-readable symbols.

Systems for optically scanning patterns and then analyzing the data to "recognize" the patterns are common. A typical form of optical pattern recognition is depicted in FIGS. 1 and 2 as a simplified version of the common linear or one-dimensional bar code 10. As depicted in FIGS. 1 and 2, a scanning beam 12 is scanned across the bar code 10 by a scanning device. A string of reflectance values are thereby produced which represent the transitions from bars to spaces along the scanning beam 12. Alternatively, an entire image or "snapshot" of the symbol 10 is taken by the reader. The data as reflected from the bar code 10 is then placed into a computer memory 14 on a pixel-by-pixel basis as pixel data 16, as depicted in FIG. 3, where each square in FIG. 3 represents a unique memory location. Since the data in the bar code 10 is arranged along one dimension, it does not matter whether the scanning takes place perpendicular to the bar code 10 as depicted in FIG. 1 or at an angle as depicted in FIG. 2. Similarly, it does not matter whether the pixel data 16 are located one-dimensionally or two-dimensionally within the computer memory 14 since the reader can readily analyze the data to determine the contents thereof. However, if the memory is large, includes multiple bar code images or images with significant background noise, the reader requires time consuming methods to locate and decode the bar code.
Optical Character Recognition (OCR) as it relates to the ability to "read" alphanumeric characters is another matter since the data is now related to a two-dimensional character. Thus, the problem is different if a character 18 being "scanned" is oriented in a known perpendicular direction as in FIG. 4 or skewed as in FIG. 5. While the character 18 can be scanned on a line-by-line basis by a raster scanning technique, it is easier and most common to simply view the character 18 two-dimensionally with, for example, a charge coupled device (CCD) camera which provides pixel data 16' within a computer memory 14 in the manner depicted in FIG. 6.
The contents of the computer memory 14 must then be analyzed on a correlated line-by-line basis as depicted in FIG. 7. The prior art techniques for analyzing the data from each line 20 of the memory 14 are complex and time-consuming, particularly if multiple fonts are to be "recognized" and orientations other than perpendicular are to be included. As can be appreciated, the prior art methodology of character recognition from the data 16' on a horizontal and vertical basis (i.e., line-by-line forward and backward and across each line pixel position-by-pixel position) cannot be accomplished in real-time. That is, the data must be scanned and then analyzed in a process that can literally take minutes for a standard page of characters.
While suffering from some of the processing intensive limitations of OCR, two-dimensional symbols or bar codes as depicted in FIG. 8 allow much more data to be represented in a much smaller space. FIG. 8 shows a so-called "Code-One" type of bar code 22. Code-One bar codes are of various types; but, each contains two components--an orientation pattern 24 and attached 2D data 26. A portion of the orientation pattern 24 from the bar code 22 of FIG. 8 is shown in FIG. 9. The orientation pattern 24 comprises a central portion 28 that defines the type of Code-One bar code present and is uniquely identifiable and locatable as to orientation; and, peripheral portions 30 that define the extents and sizing of the 2D data 26.
The central portion 28 has a plurality of "vertical" edges 32 and "horizontal" edges 34 when the bar code 22 is in its proper orientation, and the edges are in a fixed relationship to one another. Thus, regardless of the orientation, if the vertical and horizontal edges can be found, the type of bar code 22 can be determined, its orientation can be determined, and the 2D data 26 can be interpreted.
FIG. 10 shows another two-dimensional symbol, namely a PDF 417 symbol 40. The orientation pattern consists of start and stop patterns 42 and 44. The start and stop patterns include very large or wide bars relative to the rest of the symbol, 46 and 48, respectively. The bars 46 and 48 can be found within the stored image (e.g., by locating their elongated edges), and thus the position and type of the bar code 40 can be determined. Thereafter, three rows of bars and spaces 39 positioned between the start and stop patterns 42 and 44 can be decoded.
Prior art techniques for locating and decoding two-dimensional symbols still approach the problem in the same manner as with OCR or alphanumeric data. All the pixels of the scanned 2D image are stored in a computer memory and then the data is analyzed on a line-by-line basis. As compared with recognizing an "H" surrounded by white space, a reader has difficulty recognizing one of many orientation patterns 24 within the bar code 22 as in FIG. 8, or the start and stop patterns 42 and 44 within the bar code 40 as shown in FIG. 10, particularly if the patterns must be quickly located.
When scanning or imaging two-dimensional bar codes at a point of sale, work station, or the like, a recognition process can take minutes to accomplish. Readers may also have difficulty in quickly locating and decoding traditional bar codes. The finding and decoding of the data must take place in real-time or close to real-time. A typical consumer requirement is to have the data available in one second or less. Therefore, it is desirable to provide a method of analyzing optically stored data associated with machine-readable symbols or characters which can find and decode the data in real-time or close to real-time.
Most two-dimensional imagers or readers first store an image or "snapshot" of the machine-readable symbol. Thereafter, the reader attempts to locate the image of the symbol within the stored image. One method of locating a symbol image within the stored image attempts to locate an edge of a bar of the symbol, which is described in detail in U.S. patent application Ser. No. 08/607,100, entitled "Method and Apparatus for Accurately Locating Data Regions in Stored Images of Symbols," filed Feb. 26, 1996, and assigned to the assignee of the present invention. Other robust methods of locating symbol images within stored images are described in detail in U.S. patent application Ser. No. 08/687,659, entitled "Time-Efficient Method of Analyzing Imaged Input Data to Locate Two-Dimensional Machine-Readable Symbols or Other Linear Images Therein," filed Jul. 26, 1996, U.S. patent application Ser. No. 08/602,624, entitled "Method and Apparatus for Locating and Decoding Machine-Readable Symbols," filed Feb. 16, 1996, and U.S. patent application Ser. No. 08/654,925, entitled "Method and Apparatus for Locating an Decoding Machine-Readable Symbols, Including Data Matrix Symbols," filed May 29, 1996, all of which are assigned to the assignee of the present invention. These methods, however, often require significant processing time. As a result, many of these methods require high-speed, and costly, processors, or undesirable delays with slower processors.

Apparatus and method of rapidly locating edges of machine-readable symbols or other linear images


A polarizing optical element is produced by firstly forming a polarizing multilayer structure (30) on a support (31). The structure comprises an orienting layer and a polarizing layer having dichroic compounds, the dichroic compounds being oriented by the orienting layer. The multilayer structure is then pressed against one surface of the optical element (40) through the support, with a portion of adhesive placed between the structure and the optical element. The support (31) for the structure is then removed, leaving the structure (30) bonded to the optical element (40).

It is known to provide an optical element with a polarizing function by successively producing, on one surface of this element, an orienting first layer and a polarizing second layer comprising dichroic compounds. The dichroic compounds of the second layer have an angular orientation determined by the first layer. Such a method makes it possible to obtain an optical element having a high transmission contrast for polarized light. As is known, such a contrast is defined as the ratio of the transmission coefficient for light polarized parallel to the direction of the dichroic compounds to the transmission coefficient for light polarized perpendicular to this direction. Furthermore, the optical quality and the optical appearance of the polarizing optical element obtained in this way are satisfactory and compatible with many uses, especially ophthalmic use.

Method of producing a polarizing optical element

Essilor International (Compagnie Generale d'Optique)


A thin film transistor array substrate includes: a gate line provided on a substrate; a data line crossing the gate line; and a thin film transistor having a source electrode that is a portion of the data line that crosses the gate line and a drain electrode overlapping the gate line.

1. Field of the Invention
The present invention relates to a liquid crystal display, and more particularly to a thin film transistor array substrate and a fabricating method thereof.
2. Description of the Related Art
Generally, a liquid crystal displays (LCD) controls light transmittance of liquid crystal. The LCD includes a lower substrate provided with a thin film transistor array and an upper substrate provided with a color filter array that are attached to each other. A spacer for maintaining a cell gap between the two substrates is provided in a cell gap between the substrates. Liquid crystal fills in the rest of the cell gap. By using an electric field across the liquid crystal between a pixel electrode on the upper substrate and a common electrode on the lower substrate, a picture can be displayed.
The thin film transistor array includes thin film transistors provided at crossings of gate lines and data lines. An alignment film is coated on the thin film transistor array for aligning the liquid crystal. The color filter array is comprised of color filters for implementing a color, a black matrix for preventing a light leakage, and an alignment film coated thereon for the sake of an alignment of the liquid crystal.
FIG. 1 is a plan view showing a structure of the related art thin film transistor array, and FIG. 2 is a cross-section view of the thin film transistor array taken along the II-II′ line in FIG. 1. Referring to FIG. 1 and FIG. 2, the thin film transistor array includes a gate line 2 and a data line 4 provided on a lower substrate 1 crossing each other. A gate insulating film 15 is between the gate line 2 and the data line 4. A thin film transistor 6 is provided at the crossing of the gate line 2 and the data line 4. The gate line 2 supplies gate signals and the data line 4 supplies data signals. A pixel electrode 14 is provided at a pixel area defined by the gate line 2 and the data line 4.
The thin film transistor 6 allows the pixel signal of the data line 4 to be charged and maintained on the pixel electrode 14 in response to the gate signal from the gate line 2. The thin film transistor 6 includes a gate electrode 8 connected to the gate line 2, a source electrode 10 connected to the data line 4 and a drain electrode 12 connected to the pixel electrode 14. The gate electrode 8 and source electrode 10 protrude into the pixel area 5.
The thin film transistor 6 further includes an active layer 17 overlapping the gate electrode 8. A gate insulating film 15 is between the active layer 17 and the gate electrode 8. The active layer 17 provides a channel between the source electrode 10 and the drain electrode 12. The active layer 17 also overlaps the data line 4. An ohmic contact layer 19 for making an ohmic contact with the source electrode 10 and the drain electrode 12 is further provided on the active layer 17.
The pixel electrode 14 is provided at the pixel area 5 and is in contact with the drain electrode 12 of the thin film transistor 6 via a contact hole going through a protective film 21. Thus, an electric field is formed between the pixel electrode 14 to which a pixel signal is supplied via the thin film transistor 6 and the common electrode (not shown) supplied with a reference voltage. Liquid crystal molecules between the lower substrate provided with the thin film transistor array and the upper substrate provided with the color filter array are rotated due to a dielectric anisotropy. Transmittance of a light transmitting the pixel area 5 is differentiated depending upon the rotation extent of the liquid crystal molecules, thereby implementing a gray level scale. The above-mentioned related art thin film transistor array has a problem in that, since the thin film transistor 6 is formed in such a manner to be within the pixel area 5, an effective pixel area for transmitting a light of the pixel area is reduced, which causes a reduction in an aperture ratio.

Thin films transistor array substrate and fabricating method thereof


In an SOI (Silicon On Insulator) semiconductor device, a first semiconductor layer overlies a semiconductor substrate so as to sandwich an insulating layer, and second and third semiconductor layers with a different conductivity type from the second semiconductor layer are formed on the surface of the first semiconductor layer. At the interface between the first semiconductor layer and the insulating layer, a fourth semiconductor layer with a different conductivity type from the first semiconductor layer is formed. The fourth semiconductor layer includes an impurity of larger than 3×1012/cm2 so as not to be completely depleted even though a reverse bias voltage is applied between the second and third semiconductor layers.

(1)Field of the Invention
The present invention relates to an SOI (Silicon On Insulator) semiconductor device, and especially relates to a technology of improving the operating voltage of the SOI semiconductor device.
(2)Related Art
In order to electrically separate the semiconductor elements in a semiconductor integrated circuit, the dielectric isolation is often used. In the dielectric isolation, insulating layers are formed at the bottom and on the side of the semiconductor layer, which is the active layer of the semiconductor device. In this specification, this structure is referred to "dielectric isolation structure".
The SOI semiconductor device with the dielectric isolation structure solves problems facing the conventional semiconductor device using the pn junction isolation, i.e., leakage current via the pn junction and unexpected bipolar effects. The SOI semiconductor device with the dielectric isolation structure is effectively used as the high voltage semiconductor device and the semiconductor device for analog switch.
The conventional SOI semiconductor device is disclosed in Japanese Patent Nos. 2896141 and 2878689.
Each of FIGS. 1 and 2 shows the structure of an n-type high voltage MOS (Metal Oxide Semiconductor) transistor as an example of the conventional SOI semiconductor device. An n-type high voltage MOS transistor 100 in FIG. 1 is manufactured as follows. A silicon dioxide film 102 is formed on a main surface of a semiconductor substrate 101, which is a supporting substrate of the SOI substrate. Then, an n−-type semiconductor layer 103, which is to be the active layer of the SOI substrate, overlies the silicon dioxide film 102. An isolation trench 104 extending to the silicon dioxide film 102 is formed on the n−-type semiconductor layer 103 by etching so as not to be affected by the potentials of the adjacent semiconductor elements. On the side walls of the isolation trench 104, silicon dioxide films 105 are formed. The isolation trench 104 is filled with polysilicon 106. As a result, the n−-type semiconductor layer 103 is electrically isolated from the other semiconductor island. More specifically, the n−-type semiconductor layer 103 is an island dielectrically isolated by the silicon dioxide films 102 and 105.
On the surface of the island n−-type semiconductor layer 103, gate oxide films 107, gate electrodes 108, a p-type semiconductor layer 109, a source electrode 112, n+-type semiconductor layers 110 and 111, and drain electrodes 113 are formed to form the n-type high voltage MOS transistor 100. The p-type semiconductor layer 109 is formed to form a channel region. The n+-type semiconductor layers 110 are connected to the source electrode 112 and surrounded by the p-type semiconductor layer 109. The n+-type semiconductor layers 111 are connected to the drain electrodes 113.
An n-type high voltage MOS transistors 150 in FIG. 2 has almost the same structure as the n-type high voltage MOS transistor 100 in FIG. 1. The n-type high voltage MOS transistor 150 is different from the n-type high voltage MOS transistor 100 in forming an n−-type semiconductor layer 114 between the n−-type semiconductor layer 103 and the silicon dioxide film 102 and forming an n+-type semiconductor layer 115 between the n−-type semiconductor layer 103 and the silicon dioxide film 105 so as to connect to the bottom of the n+-type semiconductor layers 111. Here, the impurity concentration is set as relatively low in the n−-type semiconductor layer 114 and the n+-type semiconductor layer 115. By doing so, a depletion layer is also formed around the n−-type semiconductor layer 114 and the n+-type semiconductor layer 115 in the n−-type semiconductor layer 103 so as to improve the operating.
Generally speaking, a voltage of 0V is applied to a semiconductor substrate 101 in the n-type high voltage MOS transistors 100 and 150 in FIGS. 1 and 2. When the potential of the p-type semiconductor layer 109 is almost the same as the potential of the semiconductor substrate 101, and a large and positive voltage is applied to the n+-type semiconductor layers 111, a pn junction diode consisting of the p-type semiconductor layer 109 and the n−-type semiconductor layer 103 is in a reverse bias state. In this case, a depletion layer extends from the interface between the p-type semiconductor layer 109 and the n−-type semiconductor layer 103. Due to the large and positive voltage applied to the n+-type semiconductor layers 111, the voltage of 0V applied to the semiconductor substrate 101, and the voltage applied to the p-type semiconductor layer 109, the depletion layer evenly extends in the n−-type semiconductor layer 103 to reduce the internal electric field.
As a result, avalanche breakdown hardly occurs in the n−-type semiconductor layer 103. The operating voltage of the n-type high voltage MOS transistor depends on the occurrence of the avalanche breakdown in the n−-type semiconductor layer 103. Accordingly, avalanche breakdown prevention can improve the operating voltage in the reverse bias state.
In the conventional SOI semiconductor device, however, especially, when the potential of the n+-type semiconductor layers 111 that are connected to the drain electrodes 113 is almost the same as the potential of the semiconductor substrate 101 as the supporting substrate of the SOI substrate, a depletion layer is not sufficiently formed in the n−-type semiconductor layer 103. As a result, the operating voltage in the reverse bias state, which mainly depends on the avalanche breakdown, conspicuously deteriorates.
More specifically, in the reverse bias state, in which a large and negative voltage is applied to the p-type semiconductor layer 109, a general voltage of 0V is applied to the semiconductor substrate 101, and a voltage of 0V is applied to the n+-type semiconductor layers 111, the semiconductor substrate 101 and the n+-type semiconductor layers 111 are at the same potential. This adversely affects the extension of the depletion layer. As a result, the depletion layer extending from the pn junction interface of the between the p-type semiconductor layer 109 and the n−-type semiconductor layer 103 does not sufficiently extend to reach regions of the n−-type semiconductor layer 103 under the n+-type semiconductor layers 111. Accordingly, the electric field strength arises in the n−-type semiconductor layer 103 and the avalanche breakdown tends to occur to drastically deteriorate the reverse bias voltage of the n-type MOS transistor.
As has been described, the operating voltage cannot be kept relatively high in any reverse bias state according to the conventional SOI semiconductor device structure. The avalanche breakdown tends to easily occur to deteriorate the operating voltage in a specific condition.


A personal watercraft can be rotated in a correct direction of rotation when the personal watercraft has been overturned, and can thereby be restored to a normal, upright position. The personal watercraft includes a vessel body, an engine, and an exhaust system. The exhaust system includes a muffler, disposed on a first side of the vessel body, and an exhaust pipe connected to the muffler and formed in an inverted U-shape. During operation of the engine, exhaust gas passes through the inverted-U-shaped exhaust pipe and is subsequently discharged to the outside environment via an exhaust port. The exhaust port is disposed on a second side of the vessel body opposite the first side. The vessel body has a hollow water-receiving portion formed therein, on the second side thereof. The water-receiving portion is adapted to be submerged under water when the personal watercraft is overturned in a body of water.

1. Field of the Invention
The present invention relates to a personal watercraft incorporating structure for facilitating capsize recovery, and to a method of restoring an overturned watercraft to a normal, upright position. More particularly, the present invention relates to a personal watercraft and to a method of use thereof, in which the watercraft includes an inverted-U-shaped exhaust pipe disposed midway within an engine exhaust system, and further wherein the watercraft body includes specialized structure to assist a user in righting the watercraft, in the event that it overturns during operation.
2. Description of the Background Art
It is well known to provide a personal watercraft, or small planing boat, with an exhaust system for the driving engine thereof. It is also well known to incorporate a muffler in such an exhaust system, to which a substantially inverted-U-shaped exhaust pipe is connected. A personal watercraft having this configuration discharges exhaust gas in the muffler out through the exhaust pipe via an exhaust port. Such an exhaust system is disposed, for example, in Japanese Laid-Open Patent publication No. 2002-2593.
The art disclosed in Japanese Laid-Open Patent publication No. 2002-2593 will be described below with reference to FIG. 6. FIG. 6 illustrates the basic construction of a conventional prior art personal watercraft exhaust system.
As shown in FIG. 6, a prior art personal watercraft 100 includes an engine 101 that rotates a drive shaft 102 for driving a jet propeller 103. The personal watercraft 100 is propelled as the boat 100 expels water drawn in from a front end portion 103a of the jet propeller 103 rearwardly from a rear end portion 103b as a jet of water.
The personal watercraft 100 includes a substantially inverted-U-shaped exhaust hose 105 disposed midway within an exhaust system of the engine 101. The substantially inverted-U-shaped exhaust hose 105 functions to prevent water that has entered the exhaust hose 105 from entering into the engine 101 through a side thereof.
For example, if the personal watercraft 100 overturns in the water, an exhaust port of the exhaust hose 105 opens upwardly, making it likely that water will enter the exhaust hose 105 via the exhaust port. The water that has entered the exhaust hose 105 stays at a vertex portion 105a of the exhaust hose 105 formed into the substantially inverted-U shape, and does not enter the engine 101.
When the overturned personal watercraft 100 is to be restored to a normal, upright position, it is necessary to discharge the water remaining in the vertex portion 105a from the exhaust port. This is accomplished by turning the personal watercraft 100 such that the exhaust port is located downwardly.
To ensure that the water remaining in the vertex portion 105a is discharged properly, the personal watercraft 100 is marked, at a rear end portion thereof, with the proper direction of rotation of the overturned personal watercraft 100 when the overturned personal watercraft 100 is to be restored to a normal, upright position. Restoring the overturned personal watercraft 100 to the normal, upright position is, however, performed in a submerged condition. Therefore, it is difficult and time-consuming for an operator to determine the proper direction of rotation that is given at the rear end portion of a vessel body 100.
It is therefore an object of the present invention to provide a personal watercraft that can be swiftly rotated in a correct direction of rotation when the personal watercraft, that has been overturned, is to be restored to a normal, upright position.

Personal watercraft incorporating capsize-recovery facilitating structure, and method of using same


Methods, systems, and devices for communications are described. A device or a group of devices may generate data. The group of devices may receive a group profile from a node that identifies the devices to be included, and the group profile may include a function to be evaluated at each of the devices. The node may also provision evaluation parameters which may allow the device to provide authenticated aggregate data to a requesting third party, without sharing the data between the devices, thus concurrently maintaining individual data privacy and data provenance.

The following relates generally to wireless communications, and more specifically to secure multiparty computation for Internet of Things communications.
Wireless communications systems are widely deployed to provide various types of communication content such as voice, video, packet data, messaging, broadcast, and so on. These systems may be capable of supporting communication with multiple users by sharing the available system resources (e.g., time, frequency, and power). Examples of such multiple-access systems include fourth generation (4G) systems such as Long Term Evolution (LTE) systems, LTE-Advanced (LTE-A) systems, or LTE-A Pro systems, and fifth generation (5G) systems which may be referred to as New Radio (NR) systems. These systems may employ technologies such as code division multiple access (CDMA), time division multiple access (TDMA), frequency division multiple access (FDMA), orthogonal frequency division multiple access (OFDMA), or discrete Fourier transform spread orthogonal frequency division multiplexing (DFT-S-OFDM). A wireless multiple-access communications system may include a number of base stations or network access nodes, each simultaneously supporting communication for multiple communication devices, which may be otherwise known as user equipment (UE).
Smart devices such as cell phones, tablets, computers, cars, and home appliances are ubiquitous. Each of these devices have the ability to produce data and may connect to the internet to communicate with one another and to transmit the data to other devices and systems. Due to the capability of these devices to create or join a network with each other, the devices may be referred to as Internet of Things devices. In some examples, the data generated at these devices may be confidential data and the receiver of the data may want to verify the authenticity of the data. In some cases, the data may be received directly from a device and the device may authenticate the generated data with a signature. In other cases, the data may be created by multiple devices such as relative location data or an average value. Although current techniques provide for authentication of data from a single device, due to the varying factors of collective generated data, an improved method of collective data authentication may be desired.

Secure multiparty computation for Internet of Things communications