A radiographic imaging assembly has a first radiographic silver halide film that provides high contrast images in association with a second radiographic silver halide film that provides lower contrast images. The combination of two films, with or without one or more fluorescent intensifying screens, provides images with excellent contrast and improved exposure latitude for use in various exposure conditions and equipment. The ratio of contrast of images provided by the first and second radiographic silver halide films is at least 1.25.

This invention is directed to radiography in which radiation is aimed at certain regions of a subject to provide therapy treatment. In particular, it is directed to an asymmetric contrast radiographic portal imaging assembly containing a combination of radiographic silver halide films and to methods of use. This invention is useful in portal radiography.
In conventional medical diagnostic imaging the object is to obtain an image of a patient""s internal anatomy with as little X-radiation exposure as possible. The fastest imaging speeds are realized by mounting a dual-coated radiographic element between a pair of fluorescent intensifying screens for imagewise exposure. About 5% or less of the exposing X-radiation passing through the patient is adsorbed directly by the latent image forming silver halide emulsion layers within the dual-coated radiographic element. Most of the X-radiation that participates in image formation is absorbed by phosphor particles within the fluorescent screens. This stimulates light emission that is more readily absorbed by the silver halide emulsion layers of the radiographic element.
Examples of radiographic element constructions for medical diagnostic purposes are provided by U.S. Pat. No. 4,425,425 (Abbott et al.) and U.S. Pat. No. 4,425,426 (Abbott et al.), U.S. Pat. No. 4,414,310 (Dickerson), U.S. Pat. No. 4,803,150 (Kelly et al.), U.S. Pat. No. 4,900,652 (Kelly et al.), U.S. Pat. No. 5,252,442 (Tsaur et al.), and Research Disclosure, Vol. 184, August 1979, Item 18431.
Radiation oncology is a field of radiology relating to the treatment of cancers using high energy X-radiation. This treatment is also known as teletherapy, using powerful, high energy X-radiation machines (often linear accelerators) to exposure the cancerous tissues (tumor). The goal of such treatment is to cure the patient by selectively killing the cancer while minimizing damage to surrounding healthy tissues.
Such treatment is commonly carried out using high energy X-radiation, 4 to 25 MVp. The X-radiation beams are very carefully mapped for intensity and energy. The patient is carefully imaged using a conventional diagnostic X-radiation unit, a CT scanner, and/or an MRI scanner to accurately locate the various tissues (healthy and cancerous) in the patient. With full knowledge of the treatment beam and the patient""s anatomy, a dosimetrist determines where and for how long the treatment X-radiation will be directed, and predicts the radiation dose to the patient.
Usually, this treatment causes some healthy tissues to be overexposed. To reduce this effect, the dosimetrist provides one or more custom-designed xe2x80x9cblocksxe2x80x9d or shields of lead around the patient""s body to absorb X-radiation that would impact healthy tissues.
To determine and document that a treatment radiation beam is accurately aimed and is effectively killing the cancerous tissues, two types of imaging are carried out during the course of the treatment. xe2x80x9cPortal radiographyxe2x80x9d is generally the term used to describe such imaging. The first type of portal imaging is known as xe2x80x9clocalizationxe2x80x9d imaging in which the portal radiographic film is briefly exposed to the X-radiation passing through the patient with the lead shields removed and then with the lead shields in place. Exposure without the lead shields provides a faint image of anatomical features that can be used as orientation references near the targeted feature while the exposure with the lead shields superimposes a second image of the port area. This process insures that the lead shields are in the correct location relative to the patient""s healthy tissues. Both exposures are made using a fraction of the total treatment dose, usually 1 to 4 monitor units out of a total dose of 45-150 monitor units. Thus, the patient receives less than 20 RAD""s of radiation.
If the patient and lead shields are accurately positioned relative to each other, the therapy treatment is carried out using a killing dose of X-radiation administered through the port. The patient typically receives from 50 to 300 RAD""s during this treatment. Since any movement of the patient during exposure can reduce treatment effectiveness, it is important to minimize the time required to process the imaged films.
A second, less common form of portal radiography is known as xe2x80x9cverificationxe2x80x9d imaging to verify the location of the cell-killing exposure. The purpose of this imaging is to record enough anatomical information to confirm that the cell-killing exposure was properly aligned with the targeted tissue. The imaging film/cassette assembly is kept in place behind the patient for the full duration of the treatment. Verification films have only a single field (the lead shields are in place) and are generally imaged at intervals during the treatment regime that may last for weeks. Thus, it is important to insure that proper targeted tissue and only that tissue is exposed to the high level radiation because the levels of radiation are borderline lethal.
Portal radiographic imaging film, assembly and methods are described, for example, in U.S. Pat. No. 5,871,892 (Dickerson et al.) in which the same type of radiographic element can be used for both localization and portal imaging.
Portal imaging assemblies can be grouped into two categories. The first type of assemblies includes one or two metal plates and a radiographic silver halide film that is designed for direct exposure to X-radiation. Two such films that are commercially available are KODAK X-ray Therapy Localization (XTL) Film and KODAK X-ray Therapy Verification (XV) Film. Each of these films is generally used with a single copper or lead plate. They have the advantage of having low contrast so that a wide range of exposure conditions can be used to produce useful images. However, because high energy X-radiation is used to produce therapy portal images, the contrast of the imaged tissues (target tissues) is also very low. Coupled with the low contrast of the imaging system, the final image contrast is very low and difficult to read accurately.
The second type of portal imaging assemblies includes a fluorescent intensifying screen and a silver halide radiographic film. These assemblies include one or two metal plates, one or two fluorescent intensifying screens, and a fine grain emulsion film. Because a significant amount of the film""s exposure comes from the light emitted by the fluorescent screen(s), it is possible to use films that provide high contrast images. Thus, these imaging assemblies typically provide images having contrast 3.5 times higher than those direct imaging assemblies noted above do. However, the photospeed obtained with both types of assemblies is about the same.
Problem to be Solved
However, the imaging assemblies of the prior art present some problems. Due to their high contrast images and the variations in patient treatment dosages, patient tissue conditions (thickness), and exposing equipment, it is more difficult to obtain correct exposures. The images are either too light or too dark. Exposure can be controlled by adjusting the so-called xe2x80x9cair gapxe2x80x9d distance and monitor setting between the patient and the imaging system. Unfortunately, many therapy machines used in therapy imaging (especially therapy verification imaging) do not allow for an adjustable xe2x80x9cair gapxe2x80x9d. This is especially true for therapy verification imaging.
Thus, there is a continuing need in the health imaging industry to provide a highly effective means for portal imaging under a wide variety of exposure conditions. More particularly, there is a need for portal imaging assemblies that provide greater xe2x80x9cexposure latitudexe2x80x9d without loss of photospeed or contrast. The present invention is directed to solving these problems.
This invention provides a solution to the noted problems with a radiographic imaging assembly comprising a high contrast first radiographic silver halide film arranged in association with a lower contrast second radiographic silver halide film, the first and second radiographic silver halide films optionally further arranged in association with one or more fluorescent intensifying screens,
(a) the first radiographic silver halide film comprising a support having first and second major surfaces and is capable of transmitting X-radiation,
the first radiographic silver halide film having disposed on the first major support surface, one or more hydrophilic colloid layers including at least one silver halide emulsion layer, and on the second major support surface, one or more hydrophilic colloid layers including at least one silver halide emulsion layer,
each of the silver halide emulsion layers comprising silver halide cubic grains that have the same or different composition in each silver halide emulsion layer, and all hydrophilic layers of the first radiographic silver halide film being fully forehardened and wet processing solution permeable for image formation within 45 seconds,
(b) the second radiographic silver halide film comprising a support having first and second major surfaces and is capable of transmitting X-radiation,
the second radiographic silver halide film having disposed on the first major support surface, one or more hydrophilic colloid layers including at least one silver halide emulsion layer, and on the second major support surface, one or more hydrophilic colloid layers including at least one silver halide emulsion layer,
each of the silver halide emulsion layers comprising silver halide cubic grains that have the same or different composition in each silver halide emulsion layer, and all hydrophilic layers of the second radiographic silver halide film being fully forehardened and wet processing solution permeable for image formation within 45 seconds, and
wherein the ratio of the contrast of the first radiographic silver halide film to the contrast of the second radiographic silver halide film is at least 1.25.
Further, this invention provides a method of providing a black-and-white image comprising exposing the radiographic imaging assembly described above, and processing the first and second radiographic silver halide films, sequentially, with a black-and-white developing composition and a fixing composition, the processing being carried out within 90 seconds, dry-to-dry.
Still again, this invention provides a method of confirming the targeting of X-radiation comprising:
A) directing the X-radiation at a region of a subject containing features that are identifiable by differing levels of X-radiation absorption and creating a first image of X-radiation penetrating the subject with the radiographic imaging assembly described above wherein the X-radiation is directed to pass through the one of the radiographic silver halide films before it is passed through the other radiographic silver halide film,
B) directing X-radiation at the region of the subject and creating a second image superimposed on the first image in the first exposed radiographic silver halide film,
C) processing the first and second radiographic films of the radiographic imaging assembly to obtain a viewable image from which intended targeting of the X-radiation directed at the region in relation to the identifiable features of the subject is realized,
wherein during steps A and B, total X-radiation exposure is limited to 10 seconds or less, at least one metal screen capable of emitting electrons when exposed to X-radiation is interposed between the source of X-radiation and the first exposed radiographic silver halide film, and at least one fluorescent intensifying screen is positioned to receive electrons from the metal screen and to emit light to expose the first exposed radiographic silver halide film.
The present invention provides a means for providing high contrast images in portal imaging using a wide variety of therapy imaging machines under a wide variety of conditions. Thus, the present invention provided improved xe2x80x9cexposure latitudexe2x80x9d and xe2x80x9cdynamic rangexe2x80x9d in this important field of radiology. In addition, the radiographic imaging assembly (first and second films and optional intensifying screen) of this invention may provide improved image tone in the films and greater processing uniformity (less processing defects). In addition, all other desirable sensitometric properties are maintained and the first and second films can be rapidly processed in the same conventional processing equipment and compositions.
These advantages are achieved by using two radiographic silver halide films in combination, which films provide images with different contrasts from the same imaging X-radiation. That is, the ratio of the contrast of an image provided by the first (higher contrast) film to the contrast of an image provided by the second (lower contrast) film is at least 1.25, and preferably at least 1.75, and more preferably from about 2 to about 2.5. These films are arranged xe2x80x9cin associationxe2x80x9d that means they are generally in physical contact with no significant gap between them in the imaging assembly.
Imaging X-radiation can be directed first through either of the two radiographic silver halide films in the imaging assembly before it passes through the other radiographic silver halide film in the imaging assembly. Preferably, one or more intensifying screens are included in the radiographic imaging assembly and are arranged as described below.

Asymmetric contrast portal imaging assembly and method of use


A system for selecting a network-connected image forming apparatus wherein there are provided a plurality of network-connected image forming apparatuses and job registration means which distributes and registers a job in an image forming apparatus via a network, wherein the job registration means registers a specific mode job in an image forming apparatus already storing another specific mode job.

1. Field of the Invention
The present invention concerns a device and a method for selecting an image forming apparatus when, in an instance in which a plurality of printers, copiers, or other such image forming apparatuses are connected to a network, a job registration means distributes a job requested by a computer or other such device to an individual image forming apparatus and registers said job therein. The present invention particularly concerns a method for selecting an image forming apparatus in an instance wherein a job of a specific mode that impedes continuous job execution is registered.
2. Description of the Related Art
A conventionally known network system is one in which a plurality of image forming apparatuses is connected to a network and any of such devices is selected over the network to execute an image forming job. In such an instance, when a job requested by a computer or the like is registered for intended execution by a randomly selected image forming apparatus, if the aforementioned image forming apparatus is unable to execute the aforementioned job, an error is generated and overall system efficiency suffers.
Consequently, methods previously proposed to select an image forming apparatus when a job is distributed to an individual image forming apparatus include a method which recognizes the functional restrictions of individual image forming apparatuses and selects an image forming apparatus able to execute the requested job, and a method which searches for an image forming apparatus equipped with a printing medium requested by the job and selects an applicable device.
Depending on the type of job, a need sometimes arises to stop an image forming apparatus temporarily. For example, when printing in a manual paper supply mode, not only standard sheets, but non-standard sheets or special sheets (such as thick sheets or OHP sheets) are sometimes used. In some cases each user also commonly changes the sheets, and it is not possible to make a definitive determination about the sheets used. For this purpose, in a manual paper supply mode, an image forming apparatus is generally stopped temporarily in order to exchange sheets, and the user is requested to exchange the sheets in the manual paper supply port. In an image forming apparatus capable of storing multiple jobs, a disadvantage arises in that, when operation is stopped to exchange sheets, the execution of stored jobs is subsequently delayed, leading to reduced efficiency.
Because the aforementioned conventional selection methods merely select an image forming apparatus capable of executing a requested job, stop mode jobs and jobs pertaining to other modes are at times stored in intermingled fashion in a selected image forming apparatus, and the aforementioned problem has as yet not been resolved.
Another solution devised for the aforementioned problem is to exercise control such that, when an image forming apparatus is halted temporarily and a job pertaining to a mode not requiring a stop is next stored, such a job is executed prior to the aforementioned stop mode job. In this instance, a new problem results in that, when several non-stop mode jobs are stored, these jobs successively preempt the stop mode job and are executed continuously, and timing to restart the stop mode job cannot be achieved.

Control device and control method for network-connected device


A method of producing a carbon-based material having an activated surface includes: (a) mixing an elastomer and a carbon material, and dispersing the carbon material by applying a shear force to obtain a composite elastomer; and (b) heat-treating the composite elastomer at a temperature for vaporising an elastomer to vaporize the elastomer in the composite elastomer.

The present invention relates to a carbon-based material and a method of producing the same, and a composite material and a method of producing the same.
A composite material using a carbon material such as a carbon fiber, carbon black, graphite, or carbon nanofiber has attracted attention (e.g. Japanese Patent Application Laid-Open No. 5-78110). Such a composite material is expected to exhibit improved electrical conductivity, heat transfer properties, mechanical strength, and the like due to inclusion of the carbon material such as the carbon nanofibers.
However, the carbon material generally exhibits low wettability (affinity) with the matrix material of the composite material, and also exhibits low dispersibility in the matrix material. In particular, since the carbon nanofibers have strong aggregating properties, it is very difficult to uniformly disperse the carbon nanofibers in the matrix of the composite material. As the surface treatment for the carbon nanofibers, wet plating, evaporation, and the like have been studied. However, since the thickness of the surface-treated layer is increased, the carbon nanofibers are bonded through the surface-treated layer. Therefore, it is difficult to obtain a carbon nanofiber composite material having desired properties. Moreover, expensive carbon nanofibers cannot be efficiently utilized.

This patent is subject to a terminal disclaimer.

Carbon-based material and method of producing the same, and composite material and method of producing the same


A semiconductor wire grid may include a plurality of wires arranged separately on a substrate, formed of a semiconductor, and including a groove therebetween, wherein conductivity of the semiconductor wire grid varies according to an applied voltage such that a polarization rate of the semiconductor wire grid is controlled.

1. Field
Example embodiments relate to methods and apparatuses for a semiconductor wire grid, a display apparatus having the semiconductor wire grid, and a method of manufacturing the display apparatus.
2. Description of the Related Art
In many applied fields, the polarization characteristic of light may be used to control light emitted from a light source. For example, in a liquid crystal display (LCD) device using a liquid crystal panel, liquid crystal molecules of the liquid crystal panel may change the polarization direction of a linearly polarized light, thereby performing a function as a shutter to transmit or block the light. The LCD device may include first and second polarizers having polarization directions perpendicular to each other and a liquid crystal layer provided between the first and second polarizers. A thin film transistor (TFT) may be provided in each pixel.
The on/off of a voltage of each pixel may be controlled according to a switching operation of the TFT. For example, when a voltage of a pixel is on, the arrangement of liquid crystal molecules may be twisted. Accordingly, the polarization direction of incident light may change along the arrangement of liquid crystal molecules and may pass through the liquid crystal layer, thereby passing through the second polarizer. That is, when the liquid crystal molecules are twisted, white may be displayed. When the liquid crystal molecules are not twisted, black may be displayed.

Semiconductor wire grid, display apparatus having the same, and method of manufacturing the display apparatus


The liner provided metallic shell having an outer-facing surface and an inner-facing surface, said inner-facing surface including a cured enamel coating thereon comprising a solids mixture of an epoxy resin, a phenolic resin, carboxypolyolefin resin and polyester resin; and a shaped thermoplastic elastomer member adhered to said enamel inner surface.

The present invention relates to compositions for promoting the bonding of shaped thermoplastic elastomer articles to metallic substrates. More particularly, it relates to metallic food container closures specially adapted to use in high temperature filling, sterilization, and retort processing environments, including firmly adherent thermoplastic elastomer sealing gaskets or liners.
Vessel closures for use in food containers include a closure shell formed of either metal or plastic provided with a liner or gasket on the inner facing surface of the closure shell. The liner or gasket provides a hermetic seal between the closure member and the vessel opening. In the past, poly(vinyl chloride)-based liner formulations have been used to provide closure seals. The use of poly(vinyl chloride) resin-based compound liners is currently being discouraged for a number of reasons.
Recently, poly(vinyl chloride) (PVC) resins have received adverse EPA publicity, due to incineration, land fill, and recyclability concerns. PVC resin based plastisols conventionally employed as the closure gasket or liners, now interfere with the recyclability of both the plastic closure shell and the thermoplastic polyester bottle or container.
To overcome the shortcomings with prior art PVC-based liners and gaskets, a search is currently underway to provide substitute non-PVC type liner materials. Early efforts have focused on hot melt compositions, such as those described in U.S. Pat. No. 4,032,492 and 4,085,186. The compositions proposed include rubbery block copolymers based on styrene and butylene or ethyl vinyl acetate copolymers employed in combination with low molecular weight hydrocarbon oils, waxes, plasticizers, and other additives. The hot melt formulations generally possess low melting or softening points ranging from 70xc2x0 to 125xc2x0 C. In some food processing and packaging environments and applications, hot filling and pasteurization conditions are frequently carried out at temperatures above 70xc2x0 to 125xc2x0 C. Moreover, in hot fill, high retort food filling operations, in addition to elevated temperatures, internal vacuums of as high as 15-26 inches of mercury (Hg) are realized, which cause problems for low temperature softening sealing or gasketing materials. The proposed hot melt compositions generally cannot maintain the compressive set values and cut-through resistance values necessary to provide satisfactory hermetic seals under these high temperature processing conditions.
An additional requirement for liner and gasketing compositions is that they must possess good to excellent adhesion to the closure substrate to minimize the gasket or compound liner movement and cut through during hot fill and retort conditioning. The maintenance of hermetic seals during processing, case packing, shipping, and prolonged storage periods are all essential to successful food packaging.
More recently, it has been proposed to employ thermoplastic elastomer products to provide hermetic sealing structures for various plastic or metallic food vessel closures. Thermoplastic elastomers are thermoplastic processable polymer materials possessing easy processability and rubbery mechanical performance characteristics. Thermoplastic elastomers, often referred to as TPEs, possess a number of processing advantages over earlier rubber materials because thermoplastic elastomers may be extruded and molded to shape and used with little or no extra compounding, vulcanization, or heating steps and the recycling of scrap and the ability to use common plastics processing tools and methods is a distinct advantage. Thermoplastic elastomers possess satisfactory high temperature rubbery performance characteristics to be used as liner gaskets for food closures. However, they are difficult to satisfactorily bond to metal closure materials. For this reason, they have not been readily employed.
Another effort at providing non-PVC based liner and gasketing formulations has been to employ polypropylene polymers and copolymers as the liner compound or gasketing material. Adhesion of the polypropylene liner materials to metal substrates and polymer substrates also ran into some early difficulties. For example, in U.S. Pat. No. 4,034,132, it is disclosed that the adhesion of a propylene polymer to an enamel-coated metal surface such as is provided on a foil pull tab on a container opening is improved by incorporating an adhesion-promoting amount of carboxyl modified polypropylene resin in the metal coating enamel. In U.S. Pat. No. 4,478,677, it is disclosed that the adhesion of a heat sealed polypropylene lined aluminum foil pull tab tape strip to an enamel coated metallic surface and opening, provided with an enamel coating information based on an epoxy resin, an aminoplast resin and a carboxylated polypropylene resin is further improved and made satisfactory by the addition of a butene polymer, such as polyisobutylene, into the enamel coating composition prior to its application to the metal surface.
Other efforts more directly related to bonding thermoplastic elastomer gasketing materials to metal or plastic closures are described in U.S. Pat. No. 5,060,818 wherein adhesion of the TPE gasket to the closure is promoted by incorporating a low temperature melting point liquid paraffin resin and a polypropylene resin into a thermoplastic elastomer formulation prior to injection molding or shaping the elastomer for placement in the vessel closure. Paraffin-modified formulations may be suitable for low temperature packaging operations but they generally cannot be used in high temperature processing conditions because paraffin softens at temperatures of about 250xc2x0 F.
In addition to modifying the thermoplastic elastomer compositions per se, prior to molding or shaping to form the gasket or liner U.S. Pat. No. 5,060,818 additionally states that if an epoxy phenolic type coating is applied to the surfaces of a metallic closure, the bonding of the line to the inner side of the vessel closure may be promoted by applying a separate layer of an adhesive which contains an oxidized polyethylene resin or an acid modified olefin resin including a carboxyl modified polypropylene resin.
In our laboratories it has been found that the adhesion of shaped thermoplastic elastomer articles to metallic substrates can be improved by the addition of a carboxyl modified polyolefin resin adhesion promoter to an enamel coating composition comprising an epoxy resin and a phenolic resin. Incorporating the carboxylated polyolefin adhesion promoter for TPE materials into the enamel coating composition avoids the need to apply a separate adhesive layer comprising the carboxylated polyolefin resin to obtain satisfactory adhesion of TPE materials. While enamel compositions comprising an epoxy resin, a phenolic resin and carboxylated polyolefin resin provide these advantageous properties, it is desirable to provide coatings based on these resins better flexibility and corrosion resistance.
In accordance with this invention, and to overcome the shortcomings of the prior art arrangements, it is an object of the present invention to provide lidded, stoppered, threaded, capped, or lined metallic closures for vacuum or pressure type products requiring low orders of gas or liquid permeation with a functional hermetic seal.
It is another object of the invention to provide metallic closures provided with liner structures capable of maintaining a hermetic seal under vacuum pressure, pasteurization, hot fill, and retort processing conditions.
It is a further object of the invention to provide new and improved gasketed closures which avoid the use of PVC-based materials.
It is still another object of the invention to provide closures with non-PVC based extrusion or injection processable thermoplastic elastomers which do not require post-vulcanization to impart functional hermetic sealing closure gasket under pasteurization and sterilization conditions.
It is a further object of the present invention to provide thermoplastic elastomer-lined metallic closures exhibiting functional torque release properties.
It is still a further object of the present invention to provide metallic closures with a heat activatable enamel coating which not only promotes adhesion of functional, non-PVC based liner and gasket materials, but also provides a metallic closure exhibiting excellent product and corrosion resistance when subjected to pasteurization, sterilization, and prolonged room temperature storage conditions.
Seibel U.S. Pat. No. 5,491,031 and Japanese Patent No. 86/038744 disclose compositions suitable for promoting the adhesion of plastisols to metal substrates. For example, U.S. Pat. No. 5,491,031 discloses the use of compositions comprising an epoxy novolac resin, a phenolic resin, a polyester and an elastomer while Japanese Patent 86/038744 discloses compositions comprising a polyester resin, carboxyl containing resin and phenol, amino and/or epoxy resin. Neither of these patents disclose a liner-provided vessel closure comprising a metallic vessel closure shell having an outer-facing surface and an inner-facing surface, said inner-facing surface including a cured enamel coating thereon comprising a solids mixture of an epoxy resin, a phenolic resin, carboxypolyolefin resin, and a polyester resin; and a shaped thermoplastic elastomer liner member adhered to said enamel coated inner surface.
The objects of this invention can be attained with a liner provided metallic shell having an outer-facing surface and an inner-facing surface, said inner-facing surface including a cured enamel coating thereon comprising a solids mixture of an epoxy resin, a phenolic resin, carboxypolyolefin resin and polyester resin; and a shaped thermoplastic elastomer liner member adhered to said enamel coated inner-surface. Other things being equal, omission of the carboxypolyolefin resin results in poor adhesion of the cured enamel layer to the shaped thermoplastic elastomer liner member while omission of the polyester resin results in a more brittle enamel layer and reduced corrosion protection of the inner metallic shell.
The solids mixture for forming the cured enamel coating comprises a weight ratio of epoxy resin to phenolic resin of about 1:1 to about 1:5, a polyester resin comprises about 15 to 60 parts by weight per 100 parts by weight epoxy resin and phenolic resin and a carboxypolyolefin resin comprises from about 0.1 to 10 parts by weight per 100 parts by weight epoxy resin, phenolic resin and polyester resin.
In another aspect of this invention, the present invention additionally provides a new and improved method of bonding a shaped thermoplastic elastomer article to a metallic surface which comprises: applying an enamel coating to a metal surface of a substrate, said enamel coating containing a solids mixture comprising a weight ratio of epoxy resin to phenolic resin to about 1:1 to about 1:5, a polyester resin comprising about 15 to 60 parts by weight per 100 parts by weight epoxy resin and phenolic resin and a carboxypolyolefin resin comprising from about 0.1 to 10 parts by weight per 100 parts by weight epoxy resin, phenolic resin and polyester resin; baking the enamel coated substrate at an elevated temperature for a time sufficient to cure and harden the enamel coating composition; heat sealing a shaped thermoplastic elastomer article to the cured enamel coated metal surface; and thereafter, permitting the heat sealed assembly to cool to ambient temperatures.
Epoxy resins useful in this invention include epoxy novolac resin and glycidyl ethers of Bisphenol A.
An epoxy novolac resin useful in the present composition is a polyfunctional epoxy resin having an epoxy functionality of about 2, and preferably greater than about 2, to about 6, and preferably greater than about 2 to about 5. The epoxy novolac resin is a low molecular weight resin having an epoxide equivalent weight (EEW) of about 100 to about 220, and preferably an EEW of about 150 to about 210.
Epoxy novolac resins useful in the present invention include for example, but are not limited to, epoxy phenol novolac resins. Epoxy phenol novolac resins are represented by general structural formula (I) wherein n is about 0.2 to about 4.
The multifunctional epoxy phenol novolac resin contain a phenolic hydroxyl group per phenyl ring in random paraparaxe2x80x2, ortho-paraxe2x80x2, and ortho-orthoxe2x80x2 combinations. Epoxidation with epichlorohydrin yields the highly functional epoxy phenol novolac resins. The epoxy phenol novolac resin can be a high viscosity liquid (i.e., n about 0.2) or a solid (i.e., n greater than 3).
Nonlimiting examples of an epoxy phenol novolac resin useful in the present invention are ARALDITE(copyright) EPN 1139 available from CIBA-GEIGY Corp., Hawthorne, N.Y. and D.E.N. 431, available from Dow Chemical Co., Midland, Mich. These epoxy phenol novolac resins have an n value (from structural formula I) of 0.2, an EEW of 175 and an epoxy functionality of 2.2, and have provided a useful coating composition that effectively inhibits corrosion of metal substrates. Other nonlimiting examples of epoxy phenol novolac resins are D.E.N. 438 and ARALDITE(copyright) EPN 1138, available from Dow Chemical Co. and CIBA-GEIGY Corp., respectively, and having an n value of 1.6, an EEW of 178 and an epoxy functionality of 3.6; and D.E.N. 439 available from Dow Chemical Co. and having an n value of 1.8, an EEW of 200 and an epoxy functionality of 3.8.
Another useful class of epoxy novolac resins is the epoxy cresol novolac resins depicted in general structural formula (II), wherein n is about 1.7 to about 4.4.
The epoxy cresol novolac resins are prepared by glycidylation of o-cresol-formaldehyde condensates in the same manner as the epoxy phenol novolac resins. The epoxy functionality of the epoxy cresol novolac resins is about 2.7 to about 5.4.
Other useful epoxy novolac resins, i.e., polyfunctional epoxy resins, include but are not limited to a polynuclear phenol-glycidyl ether resin, such as the tetraglycidyl ether of tetrakis(4-hydroxyphenyl)ethane depicted in structural formula (III), and having an EEW of about 185 to about 210 and a theoretical epoxy functionality of four.
A tetraglycidylmethylenedianiline resin exemplified in structural formula (IV), as N,N,Nxe2x80x2,Nxe2x80x2-tetraglycidyl-4,4xe2x80x2-diaminophenylmethane, having an EEW of about 117 to about 133 and an epoxy functionality of about 4 also can be used as the epoxy novolac resin.
In addition, triglycidyl p-aminophenol resins, available from CIBA-GEIGY Corp., and having an EEW of about 105 to about 114 and an epoxy functionality of about 3 can be used as the epoxy novolac resin.
Another exemplary epoxy novolac resin is a triglycidyl isocyanurate depicted in structural formula (V) and having an epoxy functionality of about 3 and an EEW of about 108.
An epoxy novolac resin provides a sufficient number of crosslinking sites such that a coating composition can be cured and provide sufficient chemical and physical properties for a cured coating composition. A cured coating composition also demonstrates excellent physical properties, such as scratch resistance, adhesion and flexibility. An epoxy novolac resin also provides a sufficient number of crosslinking sites such that a cured coating composition has excellent barrier properties (i.e., exhibits excellent corrosion control).
Glycidyl ethers of Bisphenol A useful in this invention include polymeric reaction products of polyfunctional halohydrins with polyhydric phenols having the structural formula
wherein X represents the number of molecules condensed. Typical polyfunctional halohydrins are epichlorohydrin, glycerol, dichlorohydrin, and the like. Typical polyhydric phenols are resorcinol and 2,2-bis(4-hydroxyphenyl)alkanes, the latter resulting from the condensation of phenols with aldehydes and ketones, including formaldehyde, acetaldehyde, propionaldehyde, acetone, methyl ethyl ketone and the like, which result in such compounds as 2,2-bis(4-hydroxyphenyl) propane and like compounds. These epoxy resins normally contain terminal epoxy groups but may contain terminal epoxy groups and terminal hydroxyl groups.
The glycidyl ether of Bisphenol A useful in this invention generally have an average molecular weight in the range of 1400 to 6000 may be used. Preferred resins being the condensation products of epichlorohydrin and Bisphenol A, i.e., 2,2-bis(4-hydroxyphenyl)propane.
Epoxy resins based on glycidyl ethers of Bisphenol A are available commercially. Preferred examples are EPON(copyright) 1004 and EPON(copyright)1007, products of Shell Chemical Company which are the condensation products of epichlorohydrin and Bisphenol A. For maximum corrosion resistance, high molecular weight epoxy resins sold commercially under the tradename EPI-REZ(copyright)565 by Celanese Corporation is especially preferred.
The heat activatable cross-linker resin component for the epoxy resin may be any resin having a polar group which is reactive with the epoxy group, for example a hydroxyl, amino or carboxyl group. For example, phenol/formaldehyde resins, urea/formaldehyde resins, melamine/formaldehyde resins, polar group-containing vinyl resins and polar group-containing acrylic resins may be used singly or in combination.
Of these curing agent resins, the phenol/formaldehyde resins are particularly preferred from the standpoint of adhesion to the substrate, barrier properties with respect to corrosive components, and processing resistance.
The phenol/aldehyde resin component (b) used may be any phenol/aldehyde resin which contains a polynuclear phenol in the resin skeleton.
In the present invention, the term xe2x80x9cpolynuclear phenolxe2x80x9d denotes a phenol having a plurality of rings in which the phenolic hydroxyl groups are bonded. Typical examples of the polynuclear phenols are dihydric phenols represented by the formula:
wherein R represents a direct bond or a divalent bridging group. Such phenols are used conveniently for the purpose of this invention. In the dihydric phenols having divalent bridging group R are alkylene groups of the formula xe2x80x94CR1R2xe2x80x94 (in which each of R1 and R2 is a hydrogen atom, a halogen atom, an alkyl group having not more than 4 carbon atoms, or a perhaloalkyl group), xe2x80x94Oxe2x80x94, xe2x80x94Sxe2x80x94, xe2x80x94SOxe2x80x94, SO2xe2x80x94 and groups of the formula xe2x80x94NR3 (in which R3 is a hydrogen atom or an alkyl group having not more than 4 carbon atoms). Generally, R is preferably an alkylene group or an ether group. Suitable examples of such dihydric phenols are 2,2-bis(4-hydroxyphenyl)propane (Bisphenol A), 2,2-bis(4-hydroxyphenyl)butane (Bisphenol B), 1,1-bis(4-hydroxyphenyl)ethane, bis(4-hydroxyphenyl)methane (Bisphenol F), 4-hydroxyphenyl ether, and p-(4-hydroxy)phenol. Bisphenol A and Bisphenol B are most preferred.
The polyhydric phenol, either alone or in combination with another phenol, is condensed with formaldehyde to give a phenol/aldehyde resin. Monohydric phenols heretofore used in the production of resins of this type can all be used as a mixture of phenols. Generally, difunctional phenols of the following formula:
wherein R4 is a hydrogen atom or an alkyl or alkoxy group having not more than 4 carbon atoms, two of the three R4""s are hydrogen atom, and one is an alkyl or alkoxy group, and R5 is a hydrogen atom or an alkyl group having not more than 4 carbon atoms, are preferred. Other phenols such as o-cresol, p-cresol, p-t-butylphenol, p-ethylphenol, 2,3-xylenol and 2,5-xylenol, singly or in combination of two or more, are most preferred. Of course, other phenols such a phenol (carbolic acid), m-cresol, m-ethylphenol, 3,5-xylenol, m-methoxyphenol, 2,4-xylenol and 2,6-xylenol may be used, as well as other difunctional phenols such as p-aminophenol, p-nonylphenol, p-phenylphenol and p-cyclohexylphenol, all of which can be used alone or in combination with the above-mentioned polynuclear phenols in the production of the phenol-aldehyde resins.
Formaldehyde (or paraformaldehyde) is especially suitable as the aldehyde component of the phenol/aldehyde resin. Other aldehydes such as acetaldehyde, butyraldehyde and banzaldehyde may be used singly or in combination with formaldehyde. The phenol/formaldehyde resin used in this invention may be obtained by reacting the aforesaid phenol(s) and aldehyde in the presence of a basic catalyst.
An exemplary phenolic resin utilized in the present coating composition includes about 24% by weight Bisphenol A, and about 7% by weight formaldehyde. This phenolic resin is incorporated into a present coating composition as a solution containing about 50% by weight of the phenolic resin.
The polyester useful in this invention has a molecular weight of about 1,000 to about 50,000, and preferably about 1,000 to about 10,000. To achieve the full advantage of the present invention, the polyester has a molecular weight of about 1,500 to about 6,000. The identity of the polyester is not especially limited. However, it is important that a particular polyester has a sufficiently low molecular weight to impart flexibility to the cured coating composition.
The polyester is prepared by methods well known in the art from a diol, triol, polyol or mixture thereof and a polybasic carboxylic acid or anhydride, or mixture thereof. Examples of diols, triols and polyols include, but are not limited to, ethylene glycol, propylene glycol, glycerol, diethylene glycol, dipropylene glycol, triethylene glycol, tripropylene glycol, neopentyl glycol, pentaerythritol, 1,4-butanediol, trimethylol propane, isopropylidene bis(p-phenyleneoxypropanol-2) and mixtures thereof.
Examples of polybasic carboxylic acids or anhydrides include, but are not limited to, maleic anhydride, maleic acid, fumaric acid, succinic anhydride, succinic acid, adipic acid, phthalic acid, phthalic anhydride, tetrahydrophthalic anhydride, hexahydrophthalic anhydride, endomethylenetetrahydrophthalic anhydride, azelaic acid, sebacic acid, tetrachlorophthalic anhydride, chlorendic acid, isophthalic acid, trimellitic anhydride and mixtures thereof.
A typical polyester useful in this invention is prepared by admixing the following ingredients and heating at about 210xc2x0 F., then allowing the temperature to rise to about 430xc2x0 F. until the acid number is about 10.
The ingredients are mixed, and the resulting mixture is heated until the acid number reached 7.6. The polyester having a weight average molecular weight of about 3000, is present in the mixture in an amount of about 75% by weight nonvolatile material.
The carboxylated polyolefin resin which is utilized in the practice of the present invention is prepared by grafting an unsaturated dicarboxylic acid or anhydride onto an alpha-olefin backbone using high energy radiation or a peroxy catalyst as described in British Patent 1,020,740. Unsaturated dicarboxylic acids or anhydrides which can be employed to prepare the carboxyl modified polypropylene resins include maleic, tetrahydrophthalic, fumaric, itaconic, nadic, and methylnadic acids as well as their anhydrides, maleic anhydride being preferred.
The amount of unsaturated dicarboxylic acid or anhydride which can be grated into the poly(alpha olefin) backbone ranges from about 0.05 to about 10% by weight based on the total weight of the grafted polymer and preferably the amount of grafted dicarboxylic acid or anhydrides ranges from about 0.1 to about 5.0%.
Carboxyl-modified polypropylene resins are preferred as the adhesion-promoting adjuvant for the present enamel coatings. The modified polypropylene resin can be of any particle size and generally has a particle size of 0.05 to 50 microns and preferably a particle size of 35 to 40 microns.
An elastomer can be added to the coating composition to reduce the curing temperature of the enamel. Suitable elastomers include polybutenes, natural rubber, a butadiene-styrene copolymer, a polybutadiene, an isobutylene-isoprene copolymer, a polychloroprene, a polyurethane, an acrylic elastomer, a styrene isoprene copolymer, an acrylonitrile-chloroprene copolymer, a vinyl pyridine-butadiene copolymer and mixtures thereof.
In preparing the enamel coating compositions of the present invention, the epoxy resin, the phenolplast resin and polyester components are dissolved in a solvent blend, such as a mixture of ketones and aromatic hydrocarbons until these components are completely dissolved.
Suitable ketones which can be employed as solvents for epoxy resin-phenolplast resin based enamel coating formulations include methyl ethyl ketone, methyl isobutyl ketone, isophorone, cyclohexanone, diacetone alcohol and diisobutyl ketone. Aromatic hydrocarbon solvents useful as solvents for the epoxy-phenoplast resin based enamel coating formulations include benzene, toluene, xylene, and commercially available aromatic naphtha mixtures, such as Solvesso 100 or 150. An example of a useful ether alcohol is butyl cellosolve and an example of a useful ether alcohol ester is cellosolve acetate.
Antioxidants and thermal stabilizers may also be incorporated in the epoxy resin-phenolplast resin formulation to inhibit oxidation of the carboxyl modified polypropylene resin during the baking and curing of the enamel coating after its application to metal surfaces. Antioxidant compounds which have been found useful in the practice of the present invention include hindered phenolic compounds such as Irganox 1010(copyright), tetrakis[methylene-3-3,5-di-t-butyl-4-hydroxyphenyl) propionate] methane, which are incorporated in the enamel coating formulations at concentrations in the range of about 0.1 to 1.0 percent weight based on the solids content of the enamel. Lubricants, such as low molecular weight polyethylene dispersion, which are required during forming steps in container end closure manufacture may also be incorporated in the enamel composition.
Solid carboxylated polypropylene resin can be added to the organic alcohol, acid or hydrocarbon solvent at a concentration of about 1 to about 30 percent by weight and preferably about 2 to about 10 percent by weight. After the resin is added to the solvent, the mixture is heated to a temperature about 100xc2x0 C. until the resin completely dissolves in the solvent. The carboxylated polypropylene resin solution is then added to the epoxy/phenolplast resin formulation to prepare the enamel coating composition.
Organic alcohols can be used to prepare solutions of solid carboxylated polypropylene resin for incorporation in the epoxy-phenolplast resin formulations to prepare the enamel coating formulations of present inventions are long chain, saturated and unsaturated, aliphatic monohydroxy alcohols having the general formula Rxe2x80x94OH where R is a straight or branched chained saturated or ethylenically unsaturated hydrocarbon group having from 10 to 30 carbon atoms and preferably from 12 to 22 carbon atoms. Illustrative alcohols are decyl alcohol, tridecyl alcohol, lauryl alcohol, tetradecyl alcohol, cetyl alcohol, oleyl alcohol, lineoleyl alcohol, palmitoyl alcohol, arachidyl alcohol, stearyl alcohol, benhenyl alcohol, arachidonyl alcohol, myristoyl alcohol and mixtures of these alcohols.
Organic acids which may be used as solvents for the carboxylated polypropylene resin include saturated and ethylenically unsaturated alphatic acids having 10 or more carbon atoms and preferably 12 to 22 carbon atoms such as the fatty acids as capric acid, lauric acid, myristic acid, palmitic acid, isostearic acid, stearic acid and arachidic acid, undecylenic acid, myristoleic acid, palmitoleic acid, oleic acid, cetoleic acid and uric acid and mixtures of these acids.
Aliphatic hydrocarbons having 10 or more carbon atoms which may be used as solvents for the carboxylated polypropylene resin include saturated hydrocarbons such as kerosene and mineral oil as well as unsaturated hydrocarbons and particularly unsaturated hydrocarbons having olefinic or ethylenic unsaturation such as undecene, tridecene and pentadecene.
The enamel compositions of this invention can be satisfactorily applied at a solids content ranging from about 20 percent to about 70 percent by weight, based on the total weight of the liquid enamel coating composition. Generally, a solids content of 30 to 50 percent by weight is preferred.
The enamel coating composition of the present invention can be satisfactorily applied by any of the conventional methods employed in the coating industry. However, for coating of sheet metal used in container manufacture, gravure of direct roller coating are preferred methods, as the desired coating weight is easily and conventionally applied in a single coat. Spraying, dipping and flow coating are also useful methods of applying the coating dispersion.
After applying the enamel coating, it is cured and hardened by heating the coated substrate at a temperature of about 350xc2x0 F. to about 500xc2x0 F. for a period of about 20 minutes to about 1 minutes, the preferred conditions being 8-10 minutes at about 375xc2x0 F.
The preferred coating weight for coating metal closures is in the range of 1.0 to 6.0 milligrams of dry coating per square inch of substrate surface to provide an enamel surface to which the TPE shaped articles may be heat sealed.
The thermoplastic elastomer materials useful for forming the shaped gaskets or liners heat sealed to the enamel coated metallic closure surface in accordance with this invention included alloyed blends of rubbery copolymers finely dispersed in a matrix of polyolefin as a continuous phase. Illustrative alloyed blends include a polypropylene matrix including ethylene-propylene elastomers, prevulcanized butyl rubber, solid commercially under the tradename Trefsin(copyright) from Monsanto Company, ethylene-propylene-dicyclopentadiene rubber (EPDM) sold commercially under the tradenames Vistaflex(copyright) and Santoprene(copyright) from Monsanto. Other thermoplastic elastomers may include rubbery block copolymers such as triblock copolymers of the general formula ABA, where B is an elastomeric segment and A is a thermoplastic segment, and radial block copolymers of the type having a central hub and a plurality of copolymer chains emanating therefrom having the general formula AB, where B is an elastomeric segment and is attached to the hub, and A is a thermoplastic outer segment, are useable.
These copolymers are characterized by rubber-like properties similar to those of conventional rubber vulcanizates and flow properties similar to thermoplastics at temperatures above the glass transition temperature of the end blocks. The melt behavior of these compounds, with respect to shear and temperature, is similar to the behavior of conventional thermoplastics, but melt viscosities are very much higher than those of either homopolymer of the same molecular weight. Such block copolymers have been shown to exhibit a structure wherein the elastomeric and thermoplastic segments exist in separate phases. As long as the temperature is maintained below the softening point of the thermoplastic blocks, the molecules remain pinned at each end by association of the thermoplastic segments into xe2x80x9cdomainsxe2x80x9d which are connected by flexible elastomeric chains. Thus, an elastomeric network is formed with physical cross-links in the place of the chemical cross-links of vulcanizates. When heated above the glass transition temperature of the thermoplastic segments, the domains are broken up and the polymers soften and flow.
In principle, A can be any polymer normally regarded as thermoplastic, e.g. polystyrene, polymethyl methacrylate, polypropylene, etc., and B can be any polymer normally regarded as elastomeric, e.g. polyisoprene polybutadiene, polyisobutylene, polyethylene-butylene, EPDM, etc. In addition to the choice of the blocks, two other parameters influence the physical behavior of these compounds; total molecular weight, and the relative proportion of the two types of segments present and the mechanical properties of the two types of segments present. The mechanical properties of such block copolymers are essentially unaffected by molecular weight changes, however, the viscosities are quite sensitive to total molecular weight changes and this sensitivity is particularly apparent at low shear rates. Since none of these block copolymers exhibit Newtonian viscosity behavior, it is not possible to disclose the range of viscosities of compositions useful in the process of the invention in conventional viscosity units.
Changes in the relative proportions of the thermoplastic and elastomeric segments significantly influence both the mechanical and the flow properties of these block copolymers. As an example, a triblock copolymer wherein A is polystyrene and B is polybutadiene undergoes the following changes when the percent styrene content is varied. With a 13% styrene content, the polymer behaves like an undercured conventional vulcanizate. On increasing the styrene content to 27.5% the behavior of the polymer is closer to that of the conventional vulcanizates. At higher styrene contents (30 to 53 percent) the polymers exhibit a yield followed by drawing and then an elastic extension at even higher styrene content (65%), a very high yield stress is follows by a short draw and immediate break. In addition, as the sytrene content is increased, the viscosity of the polymer goes through a pronounced maximum and then decreases.
In the linear triblock copolymers useful in this invention, A, the thermoplastic segment, is preferably a polymerized alkenyl aromatic compound of average molecular weight within the range of about 2,000 to 30,000. Polystyrene is a preferred material, but polymethylstyrene, polyvinyl toluene, polyvinyl naphthalene, and the like may be substituted therefor. B, the elastomeric segment, is preferably a diene polymerized from starting materials selected from the class consisting of conjugated diene hydrocarbon compounds having four to eight carbon atoms. Elastomeric copolymers of ethylene with propylene may also be useful. B is preferably polybutadiene, polyisoprene, or polyethylene-butylene having an average molecular weight per segment within the range of 10,000 to 200,000. The thermoplastic segments should contribute between about 15 and 65 percent of the molecular weight of the triblock molecule, preferably between 20 and 40 percent. Methods of synthesis of triblock compounds of this type are known to those skilled in the art and many compounds of this type are commercially available from Shell Chemical Company under the tradename Kraton(copyright).
Some of these linear triblock copolymers are subject to a degree of thermal degradation when heated to temperatures above about 150xc2x0 C. in the present of oxygen. However, this disadvantage can be avoided by heating the copolymers in an inert atmosphere. Thermal degradation is also substantially reduced by incorporating conventional antioxidants in the compositions. The presently preferred triblock copolymers are sold by Shell Chemical Company under the tradenames Kraton G. These are characterized by significantly increased thermal stability and comprise between about 20 to 40 percent styrene and a middle block of a copolymer of ethylene with butylene.
Krayton G-2705(copyright), especially preferred, is a thermoplastic rubber available from the Shell Chemical Company. More specifically, it is a linear triblock copolymer with a center elastomeric block of an ethylene butylene polymer and end block of thermoplastic polystyrene. It supplies rubbery characteristics and film strength to the composition and is more heat resistant than the other triblock molecules.
The preferred TPE materials are also compounded with a torque release improving amount of an unsaturated fatty acid amide. Especially preferred for use as torque release additives are oleylamide and erucylamide added at amounts of 1-5% by weight of the overall TPE composition. Conventional pigments such as TiO2 or fillers such as CaSO, and fumed silicon dioxide (silica) may also be added in conventional amounts.
In accordance with this invention, the TPE gasket is bonded or formed and bonded to the cured enamel coated metallic substrate surface by high temperature extrusion, intrusion molding, injection molding, compression molding, or pre-formed gaskets may be directly bonded by heat sealing at a temperature range of about 350xc2x0 to 400xc2x0 F. Heat sealing may be accomplished by any means known to the art, such as a hot platen press or a metal jaws heated by resistance wire or by induction heating, using dwell times varying from 0.1 seconds to 5 seconds.
After the TPE gasket or liner is heat sealed and bonded to the enamel coated material surface, the assembly is allowed to cool to ambient temperature.
Further details regarding the compositions and methods and the attendant advantages provided by the present invention will become apparent from the following illustrative working examples.

Composition and method for promoting adhesion of thermoplastic elastomers to metal substrates


3D fabrics have multiple layers including an outer dimensional layer of traditional fabric and a liner layer integrated with outer layer. The 3D fabrics have variable depth, typically ranging from between about 0.25 inches to about 2.0 inches. The 3D fabrics are produced from a molding process that creates the outer dimensional layer while adhering it to the liner layer. The 3D fabrics have unique visual properties which make them desirable for a variety of applications.

Camouflage suits for bow-hunting deer typically are made with fabrics having printed patterns intended to blend in with colors and patterns in the hunter's background. More elaborate camouflage suits, such as the ghillie suit, are also available. There is a need for improved camouflage suits that blend into the background. The materials and methods developed for camouflage suits have broad applicability in other areas as well.

Three dimensional fabrics with liner strips and assembly methods therefor


The successful development of digital production content within a development organization requires that the intellectual property rights of the multiple elements of digital content introduced into the digital production content. According to the invention there is provided a means of automatically identifying the source, licenses and other associated intellectual property information associated with the digital content introduced. The invention providing for the direction of a dynamic search engine according to metadata relating to the digital content produced, wherein the digital content introduced is not identified within existing databases of intellectual properties indexed according to digital content. Further the invention provides for interfacing the dynamic search engine with a web crawler to data mine a region of the World Wide Web around the location of the digital content introduced determined by the dynamic search engine.

Digital content has been developed for as long as computers have been around. It exists in the form of computer programs, text documents, digital images, digital video, digital audio, software components, and blocks of computer code. Digital content producers integrate, compile and distribute digital content production to end-users who want it for the value, and not for the technology. Examples of such producers include software vendors, web site designers, and audiovisual content producers. During recent years, these organizations producing digital content have chosen, or been forced to, leverage externally developed content to gain efficiency in research and development. As a result, some organizations have chosen to develop digital content components for distribution not to end-users but to digital content producers themselves. For example, some companies sell digital photographs to web-site producers for use in their web sites. Another class of content producer has emerged that has chosen to produce digital content or digital content components and then distribute them for free, or with liberal licenses. A subset of these free content developers has chosen to distribute their content freely, but licensed in a way that requires content producers who use their free works either directly or to produce derivative works, to release their work under the same terms. Another trend in content development is the advent and increasing use of the Internet and the world-wide web.
Finding digital content has become easier, faster, and acceptable, to the extent that it is often expedient for digital content developers and their companies to acquire digital content or digital content components from the Internet and produce a derivative work, rather than producing original content from scratch. Alternatively developers are increasing merging externally sourced digital content, or digital content components, and embedding them within their own digital content. For example, a developer generating software for an MP3 music player might download and embed a search algorithm, allowing the user to easily search for the song they want, or an enhanced display driver produced by another developer already using the same LCD display for example.
Whilst the increased breadth and speed of access globally to digital content has significantly eased the digital content development process, the commercial enterprises ability to establish the intellectual property rights of digital content has gotten more difficult, and increases in complexity continuously as developers select, embed in real time, and in some instances with multiple development teams globally distributed to provide 24 hour code development, or addressing multiple elements of the digital content. Knowing these intellectual property rights is crucial when establishing the valuation of businesses that derive revenue or cut costs from generating and distributing original digital content, such as software companies, or companies that use digital content to derive revenue or cut costs such as television broadcasters. When a business is being audited and evaluated, they must produce accurate records detailing all external digital content in their digital content systems, including the copyright ownership, license agreements, and other terms and conditions. Given that it only takes seconds to copy significant amounts of external digital content into an enterprise, using anything from subsystem copying, downloading software from the Internet, and cutting and pasting images and text from hypertext documents from the Internet, the continuous monitoring and establishment of these property rights is difficult.
For a digital content provider a typical high-level process for documenting external content is as follows:                Identify and document each piece of external digital content in your digital content system;        Compare each documented piece of external content with publicly comparable external content, and if there is a match annotate the content with copyright owner, license, author(s), etc;        Compare all of your content with publicly comparable content, and if there is a match annotate the content with copyright owner, license, author(s);        For the remaining external content still not annotated, annotate them manually to the best of your ability with the copyright owner, license, author(s), etc
Intellectual property lawyers and software experts are often brought into the digital content developer business to drive this process, and key content developers and project leaders must spend much time compiling these lists and reports. In reality this process is often prohibitively expensive because it requires manual labor and guesswork by highly qualified and expensive intellectual property lawyers and content developers. It is also error-prone, and subject to abuse by developers' intent on hiding the source of their specific portions of the overall code forming the digital content offered by their employer or contract provider.
Additionally a large volume of digital content, such as for example a software suite or video game, may have a significant number of inserted portions of external content from a similarly large number of sources. Many such sources may in fact be private repositories of digital content, individuals developing digital content or other sources which are difficult to locate, access and verify that the digital content they host was employed within the produced digital content.
It would therefore be beneficial for digital content providers and developers to have available a centralized repository of information relating to external digital content allowing effective automation of the process described above, and thus enabling them to confidently declare the intellectual property ownership of their digital content productions. Additionally it would be beneficial for digital content providers and developers to have a means of bringing uniformity to both the digital content and the digital content metadata, thereby reducing content production costs and/or liabilities. Such uniformity is typically established via policies or rules within a development organization, each organization having different policies. In these policies and rules many of the aspects affecting the development organization are not necessarily those the developer focuses to in sourcing and introducing external content. Hence, a developer may be more interested in aspects such as file size, speed of processing, code complexity, image resolution, etc, whereas the development organization is concerned with licensing, territory restrictions, copyright, cost of use, organization sourced from, etc.
As a result any automated or even non-automated means of verifying, checking, reviewing any aspect of external digital content introduced into the development environment and introduced to a digital content under development therefore benefits from access to the fullest extent of information relating to that external digital content. As such it would be beneficial to identify such external digital content upon its introduction and extract the fullest extent of information from a centralized repository of information relating to external digital content. It would be typical for such a centralized repository to employ search engines (typically referred to a web crawler) to explore the Internet, identify digital content and store all related information gathered from the external source in association with the external digital content so that it is available to development organizations.
It would be evident that given the immense number of files upon the Internet (World Wide Web) and the rate at which this content is increasing that the web crawlers of a centralized repository have a very difficult task, perhaps one that is not achievable without expending unsustainable resources, to initially identify all new sources, identify content and extract the pertinent data for the activities discussed supra. Additionally the web crawlers should periodically return to all identified digital source locations to identify new content, verify previously identified contents information, or establish modifications to such previously identified external content. A development organization may therefore suffer delays in establishing the verified information relating to an item of external digital content that impact the development of their digital content.
It would therefore be advantageous for the web crawlers to have information relating to the activities within a development organization to establish a weighting in the search activities of the web crawlers. Accordingly a file modification event within a development organization provides data relating to external digital content introduced to adjust in a predetermined manner the activities of the web crawlers.
Accordingly the invention provides a method of automatically adjusting activities of dynamic search engines and web crawlers accessing distributed publicly and privately accessible sources of digital content to improve both decision making of development organizations introducing such digital content into their activities and the establishment of the appropriate intellectual property rights and accreditation.

System and method for enhanced direction of automated content identification in a distributed environment


The invention includes several aspects related to semiconductor-on-insulator transistors, to memory and other DRAM circuitry and arrays, to transistor gate arrays, and to methods of fabricating such constructions. In one aspect, a semiconductor-on-insulator transistor includes, a) an insulator layer; b) a layer of semiconductor material over the insulator layer; c) a transistor gate provided within the semiconductor material layer; and d) an outer elevation source/drain diffusion region and an inner elevation diffusion region provided within the semiconductor material layer in operable proximity to the transistor gate. In another aspect, DRAM circuitry includes a plurality of memory cells not requiring sequential access, at least a portion of the plurality having more than two memory cells for a single bit line contact. In still another aspect, a DRAM array of memory cells comprises a plurality of wordlines, source regions, drain regions, bit lines in electrical connection with the drain regions, and storage capacitors in electrical connection with the source regions; at least two drain regions of different memory cells being interconnected with one another beneath one of the wordlines. In yet another aspect, a DRAM array has more than two memory cells for a single bit line contact, and a plurality of individual memory cells occupy a surface area of less than or equal to 2f.times.(2f+f/N), where "f" is the minimum photolithographic feature size with which the array was fabricated, and "N" is the number of memory cells per single bit line contact within the portion.

Field effect transistors are typically comprised of a pair of diffusion regions, typically referred to as a source and a drain, spaced apart within a semiconductor substrate. Such include a gate provided adjacent to a separation region between the diffusion regions for imparting an electric field to enable current to flow between the diffusion regions. The substrate area adjacent the gate in between the diffusion regions is referred to as the channel.
The semiconductive substrate typically comprises a bulk monocrystalline silicon substrate having a light conductivity dopant impurity concentration. The diffusion regions typically have a considerably higher dopant concentration of a conductivity enhancing impurity of an opposite type. Alternately, the substrate can be provided in the form of a thin layer of lightly doped semiconductive material over an underlying insulator layer. Such are commonly referred to a semiconductor-on-insulator (SOI) constructions. The diffusion regions in SOI constructions can extend completely through the thin silicon layer, which is commonly referred to as a fully depleted SOI construction. Alternately, the diffusion regions may extend only partially into or through the thickness of the thin silicon layer, something which is commonly referred to as partially depleted SOI constructions. Regardless, a conductive gate is positioned either above or below the SOI layer to provide gating between the diffusion regions in a transistor which is substantially horizontally oriented.
Field effect transistors constitute one common type of electronic device or component utilized in integrated circuitry. High density integrated circuitry is principally fabricated from semiconductor wafers. Upon fabrication completion, a wafer contains a plurality of identical discrete die areas which are ultimately cut from the wafer to form individual chips. Die areas or cut dies are tested for operability, with good dies being assembled into encapsulating packages which are used in end-products or systems.
One type of integrated circuitry comprises memory. The basic unit of semiconductor memory is the memory cell. Capable of storing a single bit of information, the memory cell has steadily shrunk in size to enable more and more cells per area of a semiconductor substrate or wafer. Such enables integrated memory circuitry to be more compact, as well as faster in operation.
Example semiconductor memories include ROMs, RAMs, PROMs, EPROMs, and EEPROMs. Some emphasize compactness and economy over speed. Other focus on lightening-fast operation. Some store data indefinitely, while others are so temporary they must be refreshed hundreds of times every second. One of the smallest memory cells comprises the single transistor and single capacitor of a dynamic random access memory (DRAM).

Semiconductor-on-insulator transistor, memory circuitry employing semiconductor-on-insulator transistors, method of forming a semiconductor-on-insulator transistor, and method of forming memory circuitry employing semiconductor-on-insulator transistors


An improved SC fiber optic coupling is disclosed which fits within a standard SC footprint when panel mounted but which provides for a buildout whereby it may be readily cleaned yet it may be used to replace SC panel couplings having the minimum footprint required by the Telecommunications Industry Association standard for SC couplings, FOCIS 3, Fiber Optic Coupling Intermateability Standard (TIA/EIA-604-3) which provides for the dimensions to be used by SC couplings. The present invention also provides a buildout system for fiber optic connectors which allows such connectors to be assembled without any rotation therebetween. Accordingly, the present invention can be used with SC, ST, LC, and FC connectors to provide a non-rotational connection, and it can be used to manufacture ganged fiber optic coupling buildouts.

Couplings for optical fiber communication systems are well known. It is often necessary to arrange a plurality of optical fiber couplings in a panel in order to facilitate multi-fiber connections. Desirably, devices for holding couplings are mounted in the panel, but the couplings themselves are not connected to incoming or outgoing fiber paths until actually needed to provide service. Devices which are mounted in a panel to accommodate interconnections are commonly referred to as "buildout blocks" or, simply, "buildouts."
As is known and understood by those skilled in the art, it is common practice in the optical coupling art to terminate a length of optical fiber with a coupling. Once such type of optical fiber coupling which is used for terminating and connecting two optical fibers is referred to as an ST.RTM. coupling. ST.RTM. is a registered trademark of Lucent Technologies Inc. The ST.RTM. coupling is disclosed, for example, in U.S. Pat. No. 4,934,785, which issued on Jun. 19, 1990 to T. D. Mathis and Calvin M. Miller. A buildout for an ST coupling is described in U.S. Pat. No. 5,067,783, which issued on Nov. 26, 1991 to N. R. Lampert. Another type of optical fiber coupling is the SC type coupling that is shown and described in U.S. Pat. No. 5,212,752, issued to D. L. Stephenson, et al. In U.S. Pat. No. 5,274,729, which issued to King, et al. ("the '729 patent"), a variety of couplings for buildout systems are described.
In addition, in U.S. patent application Ser. No. 08/563,067, filed Nov. 27, 1995 by D. L. Stephenson, et al. a "shutter" used to close the end of a connector, in order to prevent dust from entering, is described.
As is understood by those skilled in the art, the couplings which mount in the panel are inserted from the front side of the panel and then they clip into the panel. From behind the panel a fiber optic cable which is terminated in a coupling having a ferrule is inserted. If the ferrule is not exposed, i.e., if it is enclosed in a sleeve, cleaning the end of the ferrule is extremely difficult if not impossible. Yet another problem with the couplings of the prior art is that they required the rotation of the buildout, while it was still in the block, in order to remove the buildout. The rotation of the buildout would damage the fiber end face if one of the two mated connectors was not removed.
In order to eliminate these problems, a buildout for an SC coupling has been developed. A problem with the buildout which is disclosed in the '729 patent is that its "footprint" does not fit within the Telecommunications Industry Association standard for SC couplings, FOCIS 3, Fiber Optic Coupling Intermateability Standard (TIA/EIA-604-3) which provides for the dimensions to be used by SC couplings. Accordingly, while the existing buildout works with SC couplings, which are panel mounted, if someone was to build a panel which complied with the minimum separations set for SC couplings, the SC buildout coupling of the prior art could not be used, since adjacent couplings would not fit on the panel. In view of the above, it would be desirable to have an SC coupling which could be panel mounted and which would provide a buildout whereby the cleaning of the ferrules could be facilitated.


A conversion press (20) which is readily reconfigurable to process shells of different sizes includes an endless belt (68) having a single lane of apertures (86) formed therein for transporting shells (S) along a progression of end-forming tooling (60, 62) comprising seven stations (58a-g) along an end path (59) through the press. A tab-forming tooling path (100) extends from a tab stock feeder (104) to a tab-staking station (58f) adjacent the discharge end of the press, the tab-forming path oriented at an oblique angle to the end path. The tab-forming tools (94, 96) are mounted on tab bases (112, 110) which are slidably adjustable on stationary and reciprocating press members (34, 44) along the tab path toward and away from the tab-staking station. Shells are supplied to the belt by a servo-driven downstacker (120) having feed screws (126) which engage the edge (E) of a shell within a downstacker feed chute (122) and which are adjustably mounted on a downstacker platen (135) to permit their relocation to accommodate changing shell size. Reconfiguring the press to process shells of a different size from about 1 inch to about 4 inches in diameter is accomplished by changing the belt and the end tooling, adjusting the tab tooling bases to accommodate for change in end rivet location, and changing the feed chute and adjusting the downstacker feed screw positions to correspond to the new shell diameter.

Easy-open can ends are widely used for canning many beverages and food products. An easy-open can end typically has a tear panel which can be partially or completely separated from the remainder of the can end to create an opening in the end, and an attached operating tab which may be lifted upward at one end to cause the other end to impact the tear panel causing it to at least partially separate from the rest of the can end. The tab and the end are separately manufactured components, the tab being attached to the end by an integral rivet formed out of the parent material of the can end.
Easy-open can ends are manufactured in reciprocating presses known as conversion presses. A conversion press converts thin metal discs called "shells" into can ends, including the integral rivet and tear panel, and concurrently forms operating tabs from a separate strip of thin metal and attaches the tabs to the ends via the integral rivets. The finished product is an easy-open can end, which may later be attached to a can body following a canning operation.
A conversion press commonly has a lower stationary press member which supports a series of lower "end" tools for performing work operations on the shells, and an upper reciprocating press member which supports a like number of upper "end" tools for performing work operations on the shells. Each pair of upper and lower end tools defines a press "end station", and a typical conversion press has five or more such stations for converting shells into can ends. Shells are carried through the various end stations by a shell conveyor which alternately moves the shells forward and then brings them to rest into alignment with the end stations so that work operations can be performed on the shells. In synchronization with the intermittent motion of the shell conveyor, the reciprocating press member alternately moves toward the stationary press member to sandwich the shells between the upper and lower end tools and thereby perform work operations upon them, and then moves away from the stationary press member to disengage the end tools from the shells so that the shells may each be advanced to succeeding work stations.
A conversion press further includes a "downstacker" apparatus which supplies shells to the shell conveyor. The downstacker typically supports one or more stacks of shells and sequentially dispenses the shells into the intermittently moving shell conveyor in synchronization with the conveyor motion.
With each "stroke" of the reciprocating press member, a given shell is subjected to a single work operation. Conversion of the shell into a can end having an integral rivet and tear panel typically requires at least five separate work operations. The shell is "indexed" through the five or more press stations, moving from one station to the next station during each upward stroke of the reciprocating press member. One of the press stations is dedicated to attaching or "staking" an operating tab to the can end via an integral rivet formed in the can end.
The tabs are made within the conversion press via a progression of upper and lower tab-forming tooling supported on the reciprocating and stationary press members, respectively. The tab-forming tooling is likewise arranged into a series of stations, along a path separate from the end tooling path. A strip of thin metal tab stock is fed through the series of tab stations, emerging from the last station as a strip of fully formed tabs interconnected by a skeleton of stock material. This strip of tabs is fed to tab-staking tooling at the tab-staking station, where each tab is separated from the strip and attached to a can end.
Because easy-open can ends are in high demand, press designers are constantly striving to increase the speed of conversion presses. This has led to the development of belt-based conversion presses in which shells are carried through the press by an apertured endless belt. Belt-based presses are capable of operating at higher speeds than rotary-type presses which carry the shells through the work stations along a circular-arc path by means of a "starwheel". The desire to increase production rate has further led to the development of "multiple-out" belt-based presses which operate upon two or more lanes of shells at the same time, and are therefore capable of producing two or more times as many can ends per minute as a "one-out" press operating at the same stroke rate.
Manufacturers of easy-open can ends typically produce ends of various sizes for various types of food and beverage cans. For example, currently, can ends ranging from about 1-inch diameter to about 4-inch diameter are commonly used in the canning industry. Thus, high-volume producers of can ends often employ a number of multiple-out belt-based presses, with each press being typically configured to manufacture can ends of only one size. However, these multiple-out presses are quite expensive, and consequently, low-volume producers of can ends often find that it is economically not practical to purchase several such presses in order to manufacture can ends of various sizes.
One way to solve this problem is to employ one press and reconfigure it to run different can end sizes. Although this solution is workable, substantial changes must be made to a typical single-size dedicated press in order to reconfigure it to process shells of a different size. For instance, a press is configured to have a specific "index" (i.e., center-to-center spacing between adjacent end stations) corresponding to the shells to be processed such that the shells are sufficiently spaced apart along the belt to have sufficient belt material between adjacent shell-carrying apertures and to have sufficient end tool working room, but close enough together to attain maximum throughput. If a different size shell is to be converted in the press, the index may have to be changed. Thus, when reconfiguring a press that is designed to process 2-inch diameter shells, which typically has a press index of about 3 inches, to enable the press to process 4-inch diameter shells, the press index necessarily must be increased to a value greater than 4 inches. Changing the press index, however, necessitates substantial changes in hardware, including the end tooling, the dies plates for mounting the end tooling on the press members, the endless belt, and the intermittent drive unit which drives the belt. Furthermore, changing end diameter frequently necessitates relocating the tooling for making the operating tabs as well as the tooling for staking the tabs onto the ends, since the integral rivet is usually not in the center of the end and therefore a change in end diameter translates into a change in rivet location. Such a change in tab tooling typically would require completely redesigning the mounting for the tab tooling on the press members.
Furthermore, different can end sizes often require different operating tabs. In order to minimize scrap during manufacturing of the operating tabs within a multiple-out conversion press, the interconnected tabs of the tab strip are advantageously located as close together as possible both in the direction along the strip and in the direction perpendicular thereto. Typically the most economical arrangement results in the tabs in adjacent rows being slightly staggered with respect to each other. As is well known, the resulting configuration of the tab strip completely determines the required "spread" of adjacent end tooling lanes (i.e., the center-to-center distance between adjacent lanes in the direction perpendicular to the direction of belt travel) as well as the "offset" of the lanes (i.e., the distance in the direction of belt travel between the center of an end station in one lane and the center of the corresponding end station in the adjacent lane). Reconfiguring a multiple-out press to run a different shell size with a different operating tab therefore frequently results in a change in both the "spread" and "offset" of the lanes. These changes in turn necessitate a complete redesign of the end tooling mounts.
Moreover, reconfiguring a typical press necessitates significant changes to the downstacker. A typical downstacker in a belt-based press includes a number of guide chutes corresponding to the number of end tooling lanes. Associated with each guide chute are typically two helical feed screws which engage the edge of the lowermost shell in a stack of shells and rotate to advance the shell downward through a feed opening at the lower end of the guide chute overlying a belt aperture. Reconfiguring a typical conversion press downstacker necessitates substantial changes in the downstacker structure for mounting the feed screws and their associated shafts and drive pulleys.
Apart from the problems associated with reconfiguring prior conversion presses, another significant problem with such presses is the balancing of press loads. The loads exerted on shells in a conversion press may reach several tons at certain end stations, particularly those stations in which the integral rivet is formed, while at other end stations the loads may be a fraction of a ton. In order to reduce wear and tear on the drive system components which drive the reciprocating press member as well as to maintain safe operation of the press, it is desirable to minimize the moments experienced by the reciprocating member about its center. To minimize moments, it is desirable to arrange the end stations and tab stations in such a manner that the total moments resulting from the sums of the moments produced at each of the individual end and tab work stations are minimized. In many conventional conversion presses, however, the path along which the tab strip travels to the tab-staking location is oriented normal to the path traveled by the can ends. The path defined by the tab-forming tooling typically is also oriented normal to the end path. The tab strip must travel between the two press supports on one side of the press during both the tab-forming and the tab-staking phases, since all tab-forming and tab-staking operations are preferably performed within the "footprint" of the press defined by the press supports. As a consequence, typically the tab-staking location in many such prior conversion presses must necessarily be approximately centrally located with respect to the press supports. Moreover, since the end must have the tear panel and the button which will become the integral rivet fully formed before the tab-staking operation can be performed, the high-load rivet-forming operations in such presses must of necessity be located toward the upstream press support. This results in difficulty balancing the loads in such presses.


A semiconductor device is provided that includes a leadframe, a die, and a clip. The leadframe has a flag and a power pad. The die is coupled to the flag. The clip comprises a die retaining section and a pad section. The die is coupled to the die retaining section, and the pad section extends from the die retaining section. The pad section is coupled to the power pad.

An integrated circuit ("IC") die is a small device formed on a semiconductor wafer, such as a silicon wafer and is typically cut from the wafer, coupled to a flag portion of a leadframe, and electrically connected to power pads of the leadframe via a wirebonding process. The wirebonding process may also be used to cross connect bond pads of the die or to cross connect other leads of the leadframe. The die, bond wires, and leadframe are then encapsulated and singulated from other dice to form a single packaged device.
As technology has advanced, the demand has increased for ICs that are more dense and that do not increase the size or footprint of the packaged device. Additionally, the desire has remained for an increased number of inputs and outputs between the IC and leadframe power pads. Consequently, the densities of connections between the IC die and the leadframe has increased. To produce the desired devices, fine pitch and ultra-fine pitch wire bonding have been utilized, and the bond wire diameters have decreased.
Although the aforementioned changes to the wirebonding technologies have been effective in producing operable ICs, they have certain drawbacks. For example, the decreased pitch and wire diameter may cause difficulties in the handling and the bonding of the bond wire. In particular, the bond wires may unintentionally short to other conductive structures of the packaged device, such as other bond wires, pads, leads, or the die. The bond wires may be more susceptible to shorting during IC die encapsulation as, for example, from "sweeping," where the injection or transfer of the liquid molding encapsulant may move the bond wires against other conductive structures. To decrease the shorting effect, insulated or coated wires have been used; however, these types of wires are difficult to bond to the bond pads. Some approaches have been used to remove a portion of the wire coating. But, the removal process may require additional equipment, which may increase production time and costs.
Accordingly, it is desirable to have a method for manufacturing an IC die that is simple and cost-efficient to implement. Moreover, it is desirable for the method to yield high quality devices with decreased shorting effects. Furthermore, other desirable features and characteristics of the present invention will become apparent from the subsequent detailed description of the invention and the appended claims, taken in conjunction with the accompanying drawings and this background of the invention.


A hand power tool includes a drive unit, an electronic unit, and a switching unit. The switching unit includes at least one actuating element configured to activate and deactivate the drive unit. The switching unit also includes at least one switching element configured to be positioned in at least one first switching position to set at least one first operating mode. The at least one switching element is also configured to be positioned in at least one second switching position to set at least one second operating mode.

The disclosure is based on a hand power tool, in particular an angle grinder, having a drive unit and an electronic unit, and having a switching unit, which has at least one actuating element provided for activating and deactivating the drive unit, and which comprises at least one switching element that has at least one first switching position, for setting at least one first operating mode.


A system chassis includes a bottom panel, a first sidewall, and a second sidewall. The bottom panel defines a width of the system chassis. The first sidewall extends substantially vertically from a first end of the bottom panel. The first sidewall includes a first channel vertically offset from the bottom panel. The first channel is configured to mate with a first rail of an equipment rack. The second sidewall extends substantially vertically from a second end of the bottom panel, and is opposite to the first sidewall. The second sidewall includes a second channel configured to mate with an opposing rail of the equipment rack.

The emergence of the cloud for computing applications has increased the demand for off-site installations, known as data centers, which store data and run applications accessed by remotely connected computer device users. Such data centers typically have massive numbers of servers, switches, and storage devices to store and manage data. A typical data center has physical rack structures with attendant power and communication connections. The racks are arranged in rows throughout the room or rooms of the data center. Each rack includes a frame that has vertically oriented slots or chassis between two side walls. The slots may hold multiple network devices such as servers, switches, and storage devices. There are many such network devices stacked in such rack structures found in a modern data center. For example, some data centers have tens of thousands of servers, attendant storage devices, and network switches.
Typically, a traditional server chassis is coupled to a pair of sliding rails at the bottom portion of the server chassis. For example, FIG. 1 depicts a top perspective view of a prior art server chassis 10. The server chassis 10 includes a bottom panel 12, a first side panel 14, and a second side panel 16. The first side panel 14 includes a first recess 24 extending along the length of the first side panel 14, and a first lip 25 protruding from the first recess 24. The second side panel 16 includes a second recess 26 extending along the length of the second side panel 16, and a second lip 27 protruding from the second recess 26. A motherboard 50 is installed on the bottom panel 12 of the server chassis 10. Thus, the server chassis 10 can accommodate a motherboard that has a width up to the width 18 of the bottom panel 12.
FIG. 2 shows a front view of the server chassis 10 installed in a server rack 30. The server rack 30 has a first rack wall 34, and an opposing second rack wall 36. A first slide rail 44 is supported by the first rack wall 34, while a second slide rail 46 is supported by the second rack wall 36 at a position parallel to the first slide rail 44. The first slide rail 44 fits within the first recess 24 (FIG. 1), and the second side rail 46 fits within the second recess 26 (FIG. 1), thereby allowing the server chassis 10 to be mounted in the server rack 30. In order to accommodate the first slide rail 44 and the second slide rail 46, the width 18 of the bottom panel 12 of the server chassis 10 must be less than the width 38 of the space between the first rack wall 34 and the second rack wall 36 of the server rack 30.
A need exists for more efficient utilization of chassis space, which would in turn allow faster computing performance as more components may be inserted in the chassis space. The present disclosure is directed to solving these problems.

System chassis with raised sliding channel