A method for corrective surgery in a human subject of a vocal cord defect amenable to rectification by the augmentation of tissue subadjacent to the vocal cord defect, the method comprising: placing an effective amount of autologous in vitro cultured cells into a vocal cord tissue of the subject in a position subadjacent to the vocal cord defect, wherein the vocal cord tissue is selected from the group consisting of a scar, Reinke's space, a muscle of the vocal cord, and the lamina propria, wherein the in vitro cultured cells are obtained by culturing a plurality of viable cells retrieved from the subject, and wherein the cultured cells are suspended in a collagen or modified collagen solution prior to injection of the cultured cells. The in vitro cultured cells can be fibroblasts, e.g., fibroblasts derived from dermis, fascia, connective tissue, or lamina propria.

I. In Vitro Cell Culture
The majority of in vitro vertebrate cell cultures are grown as monolayers on an artificial substrate which is continuously bathed in a nutrient medium. The nature of the substrate on which the monolayers may be grown may be either a solid (e.g., plastic) or a semi-solid (e.g., collagen or agar). Currently, disposable plastics have become a preferred substrate for cell culture.
While the growth of cells in two-dimensions is frequently used for the preparation and examination of cultured cells in vitro, it lacks the characteristics of intact, in vivo tissue which, for example, includes cell-cell and cell-matrix interactions. Therefore, in order to characterize these functional and morphological interactions, various investigators have examined the use of three-dimensional substrates in such forms as a collagen gel (Yang et al., Cancer Res. 41:1027 (1981); Douglas et al., In Vitro 16:306 (1980); Yang et al., Proc. Nat'l Acad. Sci. 2.088 (1980)), cellulose sponge (Leighton et al., J. Nat'l Cancer Inst. 12: 545 (1951)), collagen-coated cellulose sponge (Leighton et al., Cancer Res. 28: 286 (1968)), and GELFOAM® (Sorour et al., J. Neurosurg. 43:742 (1975)). Typically, these aforementioned three-dimensional substrates are inoculated with the cells to be cultured, which subsequently penetrate the substrate and establish a "tissue-like" histology similar to that found in vivo. Several attempts to regenerate "tissue-like" histology from dispersed monolayers of cells utilizing three-dimensional substrates have been reported. For example, three-dimensional collagen substrates have been utilized to culture a variety of cells including breast epithelium (Yang, Cancer Res. 41:1021 (1981)), vascular epithelium (Folkman et al., Nature 288:551 (1980)), and hepatocytes (Sirica et al., Cancer Res. 76:3259 (1980)), however long-term culture and proliferation of cells in such systems has not yet been achieved. Prior to the present invention, a three-dimensional substrate had not been utilized in the autologous in vitro culture of cells or tissues derived from the dermis, fascia, or lamina propria.
II. Augmentation and/or Repair of Dermal and Subcutaneous Tissues
In the practice of cosmetic and reconstructive plastic surgery it is frequently necessary to employ the use of various injectable materials to augment and/or repair defects of the subcutaneous or dermal tissue, thus effecting an aesthetic result. Non-biological injectable materials (e.g., paraffin) were first utilized to correct facial contour defects as early as the late nineteenth century. However, numerous complications and the generally unsatisfactory nature of long-term aesthetic results caused the procedure to be rapidly abandoned. More recently, the use of injectable silicone became prevalent in the 1960's for the correction of minor defects, although various inherent complications also limited the use of this substance. Complications associated with the utilization of injectable liquid silicone include local and systemic inflammatory reactions, formation of scar tissue around the silicone droplets, rampant and frequently-distant unpredictable migration throughout the body, and localized tissue breakdown. Due to these potential complications, silicone is not currently approved for general clinical use. Although the original proponents of silicone injection have continued experimental programs utilizing specially manufactured "Medical Grade" silicone (e.g., Dow Corning MDX 4.4011®) with a limited number of subjects, it appears highly unlikely that its use will be generally adopted by the surgical community. See e.g., Spira and Rosen, Clin. Plastic Surgery 20:181 (1993); Matton et al., Aesthetic Plastic Surgery 9:133 (1985).
It has also been suggested to compound extremely small particulate species in a lubricious material and inject such combination micro-particulate media subcutaneously for both soft and hard tissue augmentation and repair, however success has been heretofore limited. For example, bioreactive materials such as hydroxyapatite or cordal granules (osteo conductive) have been utilized for the repair of hard tissue defects. Subsequent undesirable micro-particulate media migration and serious granulomatous reactions frequently occur with the injection of this material. These undesirable effects are well-documented with the use of such materials as polytetrafluoroethylene (TEFLON®) spheres of small diameter (˜90% of particles having a diameter of 30 μm) in glycerin. See e.g., Malizia et al., JAMA 251:3277 (1984). Additionally, the use of very small diameter particulate spheres (˜1-20 μm) or small elongated fibrils (˜1-30 μm in diameter) of various materials in a biocompatible fluid lubricant as injectable implant composition are disclosed in U.S. Pat. No. 4,803,075. However. while these aforementioned materials create immediate augmentation and/or repair of defects, they also have a tendency to migrate and be reabsorbed from the original injection site.
The poor results initially obtained with the use of non-biological injectable materials prompted the use of various non-immunogenic, proteinaceous materials (e.g., bovine collagen and fibrin matrices). Prior to human injection, however, the carboxyl- and amino-terminal peptides of bovine collagen must first be enzymatically-degraded, due to its highly immunogenic nature. Enzymatic degradation of bovine collagen yields a material (atelocollagen) which can be used in limited quantities in patients pre-screened to exclude those who are immunoreactive to this substance. The methodologies involved in the preparation and clinical utilization of atelocollagen are disclosed in U.S. Pat. No. 3,949,073; U.S. Pat. No. 4,424,208; and U.S. Pat. No. 4,488,911. Atelocollagen has been marketed as ZYDERM® brand atelocollagen solution in concentrations of 35 mg/ml and 65 mg/ml. Although atelocollagen has been widely employed, the use of ZYDERM® has been associated with the development of anti-bovine antibodies in approximately 90% of patients and with overt immunologic complications in 1-3% of patients. See DeLustro et al., Plastic and Reconstructive Surgery 79:581 (1987).
Injectable atelocollagen solution also was shown to be absorbed from the injection site, without replacement by host material, within a period of weeks' to months. Clinical protocols calling for repeated injections of atelocollagen are, in practice, primarily limited by the development of immunogenic reactions to the bovine collagen. In order to mitigate these limitations, bovine atelocollagen was further processed by cross-linking with 0.25% glutaraldehyde, followed by filtration and mechanical shearing through fine mesh. The methodologies involved in the preparation and clinical utilization of this material are disclosed in U.S. Pat. No. 4,582,640 and U.S. Pat. No. 4,642,117. The modified atelocollagen was marketed as ZYPLAST® brand cross-linked bovine atelocollagen. The propertied advantages of cross-linking was to provide increased resistance to host degradation, however this was off-set by an increase in solution viscosity. In addition, cross-linking of the bovine atelocollagen was found to decrease the number of host cells which infiltrated the injected collagen site. The increased viscosity, and in particular irregular increased viscosity resulting in "lumpiness," not only rendered the material, more difficult to utilize, but also made it unsuitable for use in certain circumstances. See e.g., U.S. Pat. No. 5,366,498. In addition, several investigators have reported that there is no or marginally-increased resistance to host degradation of ZYPLAST® cross-linked bovine atelocollagen in comparison to that of the non-cross-linked ZYDERM® atelocollagen and that the overall longevity of the injected material is, at best, only 4-6 months. See e.g., Ozgentas et al., Ann. Plastic Surgery 33:171 (1994); and Matti and Nicolle, Aesthetic Plastic Surgery 14:227 (1990). Moreover, bovine atelocollagen cross-linked with glutaraldehyde may retain this agent as a high molecular weight polymer which is continuously hydrolyzed, thus facilitating the release of monomeric glutaraldehyde. The monomeric form of glutaraldehyde is detectable in body tissues for up to 6 weeks after the initial injection of the cross-linked atelocollagen. The cytotoxic effect of glutaraldehyde on in vitro fibroblast cultures is indicative of this substance not being an ideal cross-linking agent for a dermal equivalent which is eventually infiltrated by host cells and in which the bovine atelocollagen matrix is rapidly degraded, thus resulting in the release of monomeric glutaraldehyde 5 into the bodily tissues and fluids.
Similarly, chondroitin-6-sulfate (GAG), which weakly binds to collagen at neutral pH, has also been utilized to chemically modify bovine protein for tissue graft implantation. See Hansborough and Boyce, JAMA 136:2125 (1989). However, like glutaraldehyde, GAG may be released into the tissue causing unforeseen long-term effects on human subjects. GAG has been reported to increase scar tissue formation in wounds, which is to be avoided in grafts. Additionally, a reduction of collagen blood clotting capacity may also be deleterious in the application in bleeding wounds, as fibrin clot contributes to an adhesion of the graft to the surrounding tissue.
The limitations which are imposed by the immunogenicity of both modified and non-modified bovine atelocollagen have resulted in the isolation of human collagen from placenta (see e.g., U.S. Pat. No. 5,002,071); from surgical specimens (see e.g., U.S. Pat. No. 4,969,912 and U.S. Pat. No. 5,332,802); and cadaver (see e.g., U.S. Pat. No. 4,882,166). Moreover, processing of human-derived collagen by cross-linking and similar chemical modifications is also required, as human collagen is subject to analogous degradative processes as is bovine collagen. Human collagen for injection, derived from a sample of the patient's own tissue, is currently available and is marketed as AUTOLOGEN®. It should be noted, however, that there is no quantitative evidence which demonstrates that human collagen injection results in lower levels of implant degradation than that which is found with bovine collagen preparations. Furthermore, the utilization of autologous collagen preparation and injection is limited to those individuals who have previously undergone surgery, due to the fact that the initial culture from which the collagen is produced is derived is from the tissue removed during the surgical procedure. Therefore, it is evident that, although human collagen circumvents the potential for immunogenicity exhibited by bovine collagen, it fails to provide long-term therapeutic benefits and is limited to those patient who have undergone prior surgical procedures.
An additional injectable material currently in use as an alternative to atelocollagen augmentation of the subjacent dermis consists of a mixture of gelatin powder, -aminocapronic acid, and the patient's plasma marketed as FIBREL®. See Multicenter Clinical Trial, J. Am. Acad. Dermatology 16:1155 (1987). The action of FIBREL® appears to be dependent upon the initial induction of a sclerogenic inflammatory response to the augmentation of the soft tissue via the subcutaneous injection of the material. See e.g., Gold, J. Dermatologic Surg. Oncology, 20:586 (1994). Clinical utilization of FIBREL® has been reported to often result in an overall lack of implant uniformity (i.e., "lumpiness") and longevity, as well as complaints of patient discomfort associated with its injection. See e.g., Millikan et al., J. Dermatologic. Surg. Oncology, 17:223 (1991). Therefore, in conclusion, none of the currently utilized protein-based injectable materials appears to be totally satisfactory for the augmentation and/or repair of the subjacent dermis and soft tissue.
The various complications associated with the utilization of the aforementioned materials have prompted experimentation with the implantation (grafting) of viable, living tissue to facilitate augmentation and/or repair of the subjacent dermis and soft tissue. For example, surgical correction of various defects has been accomplished by initial removal and subsequent re-implantation of the excised adipose tissue either by injection (see e.g., Davies et al., Arch. of Otolarynaology-Head and Neck Surgery 121:95 (1995); McKinney & Pandya, Aesthetic Plastic Surgery 18: 383 (1994); and Lewis, Aesthetic Plastic Surgery 17:109 (1993)) or by the larger scale surgical-implantation (see e.g., Ersck, Plastic & Reconstructive Surgery 87: 219 (1991)). To perform both of the aforementioned techniques a volume of adipose tissue equal or greater than is required for the subsequent augmentation or repair procedure must be removed from the patient. Thus, for large scale repair procedures (e.g., breast reconstruction) the amount of adipose tissue which can be surgically-excised from the patient may be limiting. In addition, other frequently encountered difficulties with the aforementioned methodologies include non-uniformity of the injectate, unpredictable longevity of the aesthetic effects, and a 4-6 week period of post-injection inflammation and swelling. In contrast, in a preferred embodiment, the present invention utilizes the surgical engraftment of autologous adipocytes which have been cultured on a solid support typically derived from, but not limited to, collagen or isolated extracellular matrix. The culture may be established from a simple skin biopsy specimen and the amount of adipose tissue which can be subsequently cultured in vitro is not limited by the amount of adipose tissue initially excised from the patient.
Living skin equivalents have been examined as a methodology for the repair and/or replacement of human skin. Split thickness autographs, epidermal autographs (cultured autogenic keratinocytes), and epidermal allographs (cultured allogenic keratinocytes) have been used with a varying degree of success. However, unfortunately, these forms of treatment have all exhibited numerous disadvantages. For example, split thickness autographs generally show limited tissue expansion, require repeated surgical operations, and give rise to unfavorable aesthetic results. Epidermal autographs require long periods of time to be cultured, have a low success ("take") rate of approximately 30-48%, frequently form spontaneous blisters, exhibit contraction to 60-70% of their original size, are vulnerable during the first 15 days of engraftment, and are of no use in situations where there is both epidermal and dermal tissue involvement. Similarly, epidermal allografts (cultured allogenic keratinocytes) exhibit many of the limitations which are inherent in the use of epidermal autographs. Additional methodologies have been examined which involve the utilization of irradiated cadaver dermis. However, this too has met with limited success due to, for example, graft rejection and unfavorable aesthetic results.
Living skin equivalents comprising a dermal layer of rodent fibroblast cells cast in soluble collagen and an epidermal layer of cultured rodent keratinocytes have been successfully grafted as allografts onto Sprague Dawley rats by Bell et al., J. Investigative Dermatology 81:2 (1983). Histological examination of the engrafted tissue revealed that the epidermal layer had fully differentiated to form desmonosomes, tonofilaments, keratohyalin, and a basement lamella. However, subsequent attempts to reproduce the living skin equivalent using human fibroblasts and keratinocytes has met with only limited success. In general, the keratinocytes failed to fully differentiate to form a basement lamella and the dermo-epidermal junction was a straight line.
The present invention includes the following methodologies for the repair and/or augmentation of various skin defects: (1) the injection of autologously cultured dermal or fascial fibroblasts into various layers of the skin or injection directly into a "pocket" created in the region to be repaired or augmented, or (2) the surgical engraftment of "strands" derived from autologous dermal and fascial fibroblasts which are cultured in such a manner as to form a three-dimensional "tissue-like" structure similar to that which is found in vivo. Moreover, the present invention also differs on a two-dimensional level in that "true" autologous culture and preparation of the cells is performed by utilization of the patient's own cells and serum for in vitro culture.
III. Vocal Cord Tissue Augmentation and/or Repair
Phonation is accomplished in humans by the passage of air past a pair of vocal cords located within the larynx. Striated muscle fibers within the larynx, comprising the constrictor muscles, function so as to vary the degree of tension in the vocal cords, thus regulating both their overall rigidity and proximity to one another to produce speech. However, when one (or both) of the vocal cords becomes totally or partially immobile, there is a diminution in the voice quality due to an inability to regulate and maintain the requisite tension and proximity of the damaged cord in relation to that of the operable cord. Vocal cord paralysis may be caused by cancer, surgical or mechanical trauma, or similar afflictions which render the vocal cord incapable of being properly tensioned by the constrictor muscles.
One therapeutic approach which has been examined to allow phonation involves the implantation or injection of biocompatible materials. It has long been recognized that a paralyzed or damaged vocal cord may be repositioned or supported so as to remain in a fixed location relative to the operable cord such that the unilateral vibration of the operable cord produces an acceptable voice pattern. Hence, various surgical methodologies have been developed which involve the formation of an opening in the thyroid cartilage and subsequently providing a means for the support and/or repositioning of the paralyzed vocal cord.
For example, injection of TEFLON® into the paralyzed vocal cord to increase its inherent "bulk" has been described. See e.g., von Leden et al., Phonosurgery 3:175 (1989). However, this procedure is now considered unacceptable due to the inability of the injected TEFLON® to close large glottic gaps, as well as its tendency to induce inflammatory reactions resulting in the formation of fibrous infiltration into the injected cord. See e.g., Maves et al., Phonosurgery: Indications and Pitfalls 98:577 (1989). Moreover, removal of the injected TEFLON® may be quite difficult should it subsequently be desired or become necessary.
Another methodology for supporting the paralyzed vocal cord which has been employed involves the utilization of a custom-fitted block of siliconized rubber (SILASTIC®). In order to ensure the proper fit of the implant, the surgeon hand carves the SILASTIC® block during the procedure in order to maximize the ability of the patient to phonate The patient is kept under local anesthesia so that he or she can produce sounds to test the positioning of the implant. Generally, the implanted blocks are formed into the shape of a wedge which is totally implanted within the thyroid cartilage or a flanged plug which can be moved back-and-forth within the opening in the thyroid cartilage to fine-tune the voice of the patient.
Although SILASTIC® implants have proved to be superior over TEFLON® injections, there are several areas of dissatisfaction with the procedure including difficulty in the carving and insertion of the block, the large amount of time required for the procedure, and a lack of an efficient methodology for locking the block in place within the thyroid cartilage. In addition, vocal cord edema, due to the prolonged nature of the procedure and repeated voice testing during the operation, may also prove problematic in obtaining optimal voice quality.
Other methodologies which have been utilized in the treatment of vocal cord paralysis and damage include GELFOAM® hydroxyapatite, and porous ceramic implants, as well as injections of silicone and collagen. See e.g., Koufman, Larynagolastic Phonosurgery (1988). However, these materials have also proved to be less than ideal due to difficulties in the sizing and shaping of the solid implants as well as the potential for subsequent immunogenic reactions. Therefore, there still remains a need for the development of a methodology which allows the efficacious treatment of vocal cord paralysis and/or damage.

Augmentation and repair of vocal cord tissue defects


A sand control completion (100) for installation in a wellbore (102) includes first and second packers (114, 116) that define a first zone (110) in the wellbore (102). A production tubing (120) extends substantially through the first zone (110). Positioned between the first and second packers (114, 116) are a sand control screen (130), an inflow control valve (122) and a crossover valve (126). The sand control screen forms a first annulus (152) with the production tubing (120) and a second annulus with the wellbore (102). The inflow control valve (122) is operable to selectively allow and prevent fluid communication between the first annulus (152) and the interior of the production tubing (120). The crossover valve (126) is operable to selectively allow and prevent fluid communication between the production tubing (120) and the second annulus.

It is well known in the subterranean well drilling and completion art that relatively fine particulate materials may be produced during the production of hydrocarbons from a well that traverses an unconsolidated or loosely consolidated formation. Numerous problems may occur as a result of the production of such particulate. For example, the particulate causes abrasive wear to components within the well, such as tubing, pumps and valves. In addition, the particulate may partially or fully clog the well creating the need for an expensive workover. Also, if the particulate matter is produced to the surface, it must be removed from the hydrocarbon fluids using surface processing equipment.
One method for preventing the production of such particulate material is to gravel pack the well adjacent to the unconsolidated or loosely consolidated production interval. In a typical gravel pack completion, a sand control screen is lowered into the wellbore on a work string to a position proximate the desired production interval. A fluid slurry including a liquid carrier and a relatively coarse particulate material, such as sand, gravel or proppants which are typically sized and graded and which are typically referred to herein as gravel, is then pumped down the work string and into the well annulus formed between the sand control screen and the perforated well casing or open hole production zone.
The liquid carrier either flows into the formation or returns to the surface by flowing through a wash pipe or both. In either case, the gravel is deposited around the sand control screen to form the gravel pack, which is highly permeable to the flow of hydrocarbon fluids but blocks the flow of the fine particulate materials carried in the hydrocarbon fluids. As such, gravel packs can successfully prevent the problems associated with the production of these particulate materials from the formation.
In other cases, it may be desirable to stimulate the formation by, for example, performing a formation fracturing and propping operation prior to or simultaneously with the gravel packing operation. Hydraulic fracturing of a hydrocarbon formation is sometimes necessary to increase the permeability of the formation adjacent the wellbore. According to conventional practice, a fracture fluid such as water, oil, oil/water emulsion, gelled water or gelled oil is pumped down the work string with sufficient volume and pressure to open multiple fractures in the production interval. The fracture fluid may carry a suitable propping agent, such as sand, gravel or proppants, which are typically referred to herein as proppants, into the fractures for the purpose of holding the fractures open following the fracturing operation.
It is also well known in the subterranean well drilling and completion art that it is desirable to install smart well or intelligent well completions that enable the management of production fluids from different parts of the production interval or intervals. Specifically, these smart well completions typically include one or more sensing or control mechanisms such as temperature sensors, pressure sensors, flow-control devices, flow rate measurement devices, fluid composition measurement devices and the like. These smart well devices are typically operated using one or more control cables that include hydraulic lines, electrical lines, fiber optic bundles and the like. The control cables provide for communication between the smart well devices and the surface such as transmission of sensors data to the surface or transmission of commands from the surface to operate a flow control device from one operational state to another.
It would therefore be desirable to combine smart well capabilities into a sand control completion. Accordingly, attempts have been made to combine smart well capabilities into a sand control completion. For example, prior art completions have included convention sand control techniques for a lower zone followed by the insertion of an upper zone completion with a siphon string that is stabbed into the lower zone completion. A valve within the siphon string controls flow from the lower zone. Production from the upper zone flows through the annulus between the siphon string and the upper completion into the casing annulus and a flow control device is used to control flow from the annulus into the production tubing. This type of configuration, however, has limited applicability as only two zones can be controlled in this manner.
As another example, a multizone, single trip completion has been attempted wherein each completion includes an upper packer, a sand control screen having a blank base pipe, a flow control device and a lower packer. Production from the lower zone or zones flows through the interior of the flow control device and blank base pipe, while production from the upper zone flows through an annulus between the filter medium and the blank pipe of the sand control screen into the casing annulus and through the flow control device into the production tubing. While this type of configuration may be used to complete more than two zones, flow from each zone is severely restricted due to the relative small annular area between the filter medium and the blank pipe of the sand control screen.
Therefore, a need has arisen for a sand control completion having smart well capability that provides for the monitoring and control of production from multiple zones within the completion. A need has also arisen for such a sand control completion having smart well capability that is not limited to a two zone completion. Further, need has arisen for such a sand control completion having smart well capability that does not restrict production from the multiple zones being produced.

Sand control completion having smart well capability and method for use of same


A device for managing urinary incontinence in a human female comprises a soft, non-porous dome-shaped suction cup like device having a flat annular zone about its periphery and adapted to cooperate with the vestibule floor of female genitalia for blocking the flow of urine without being in physical contact with the urethral meatus.

I. Field of the Invention
This invention relates to devices used to relieve or mitigate the problems associated with human female stress incontinence and more specifically to a removable seal for covering the urethral meatus of a human female subject.
II. Discussion of the Prior Art
A good discussion of problems relating to female urinary incontinence is set forth in the "Background of the Invention" of U.S. Pat. No. 5,336,208 to Rosenbluth et al. That material is incorporated by reference herein.
The Rosenbluth et al. '208 patent describes a urethral meatus occlusion device for managing urinary incontinence in a human female that includes a resilient pad shaped to fit between the labia minora and the floor of the vestibule of the vulva to occlude the urethral meatus. The device is held in place by an adhesive to provide a sealing engagement with the urethral meatus. The pad comprises a highly absorbent, hydrophilic material having a longitudinal ridge with a posterior edge to allow gripping during installation and removal. In accordance with another disclosed embodiment, the pad comprises a flexible sack filled with a liquid or gel that will conform to the female genitalia so as to again occlude the urethral meatus.
The current invention is an improvement over Rosenbluth et al. '208 in that the current invention employs both a minor vacuum from the dome and an adhesive boarder to provide secure attachment of the device to the vestibule floor of the female vulva. Lesser adhesive surface used results in a lesser area of occluded skin surfaces. This permits the vestibule floor skin to breathe better and lessen the possibility of skin ulceration. Furthermore, the current invention offers another improvement over the device described in the Rosenbluth patent in that the urethral meatus will not be occluded by the physical contact of adhesives as in Rosenbluth. This minimizes the possibility of infection by migration of foreign substances directly into the metal opening, as well as physical irritation to the meatus. The minor suction provided by my invention also helps to seal the metal opening and further aid in the continence of the patient and the minimization of upward migration of foreign materials.


A raveling-preventing agent for a glass fiber woven fabric, which contains as essential components a reaction product from an epoxy resin having an epoxy equivalent of 150 to 1,000 and a molecular weight of 500 to 2,000 and a hydroxyl group-containing amine compound, and an isocyanate curing agent. The raveling-preventing agent firmly binds glass fibers together and prevents the raveling of edge-forming warp yarns when applied to sectioned marginal portions of a glass fiber woven fabric. Further it is free from swelling in a solvent used in a thermosetting resin varnish.

1. Field of the Invention
The present invention relates to a raveling-preventing agent for a glass fiber woven fabric. The raveling-preventing agent of the present invention is preferably used for preventing the marginal raveling and the margin of a glass fiber woven fabric which is produced by means of an air-jet loom, etc., and used for producing a copper-clad laminate.
2. Prior Art
A glass fiber woven fabric has been mostly produced by means of a shuttle loom, while it is recently increasingly produced by means of a shuttleless loom such as an air-jet loom. In the field of copper-clad laminates where a large amount of glass fiber woven fabrics are used, nearly all of the glass fiber woven fabrics are produced by means of an air-jet loom. When an air-jet loom is used, the weft is cut every time when it is allowed to run from edge to edge across a fabric to be produced. As a result, a loose marginal portion of the weft yarns is present in each of the side portions of the fabric (the term "loose marginal portion" is also called "feathered edge"). As is well known, a glass fiber woven fabric for a copper-clad laminate is impregnated with a varnish of a thermosetting resin such as an epoxy resin and dried to prepare a prepreg. A plurality of the so-prepared prepregs were stacked, copper foil(s) is/are stacked, and heat and pressure are applied to obtain a copper-clad laminate.
When a prepreg is prepared from a glass fiber woven fabric having feathered edges, produced by means of a shuttleless loom such as an air-jet loom, the following problems occur.
The first problem is that since the feathered edges of a glass fiber woven fabric contain an excess of a resin, the feathered edges tend to have a larger thickness than any other portion. When a prepreg having a larger thickness in the feathered edges as described above is cut to a predetermined size and stacked, the resultant stack has a larger thickness in a place where the above feathered edges are present together, and the stack is consequently not entirely uniform in thickness. The above prepreg stack which is not uniform in thickness across the entirety of its width causes a variety of disadvantages when used for producing a product. For example, when a copper-clad laminate is produced from such a prepreg stack, there is a defect in that the prepreg stack cannot be pressed in the entirety of its width.
The second problem is that when the form of each edge of the prepreg is viewed along its length, each edge does not have a linear form, but has an uneven form due to the feathered edges. When the prepreg whose edges have an uneven form is cut to a predetermined size and stacked, there is a defect in that it is difficult to bring the edge of the marginal portions in line. Further, when the edges of the marginal portions are brought in line, the uneven edge portions are partially cut or broken to pieces and the resulting pieces are spattered to be included in the prepreg, which inclusion causes defective products.
The third problem is that when a prepreg is produced, the loose marginal portions of a glass fiber woven fabric are partially cut or broken and the resulting pieces are included in a varnish and adhere to the prepreg surface, which ends up in defective products.
When a prepreg is prepared from a glass fiber woven fabric having loose marginal portions, the foregoing problems arise, while the above first problem similarly occurs concerning the marginal portion of a glass fiber woven fabric produced by means of a shuttle loom.
For avoiding the first and second problems, there may be employed a method in which the marginal portion is removed by cutting it off from the produced prepreg. In this case, however, the third problem cannot be avoided. Further, the yields of the glass fiber woven fabric and varnish decrease, which is costwise undesirable.
Further, there may be employed a method in which the marginal portion of a glass fiber woven fabric is removed before the prepreg is prepared from the glass fiber woven fabric, and some proposals have been made. For example, there is a method in which the loose marginal portion is cut off by melting it with laser light while the remaining end portion is simultaneously bound. There is also a method in which yarns of a thermoplastic resin are incorporated as marginal portions of part of warp yarns for a glass fiber woven fabric and the yarns of a thermoplastic resin are fused after the glass fiber woven fabric is produced. However, the method using laser light has not yet been put to practical use, since it has problems in that the cutting rate by melting cannot be increased and that the melting drip of small balls in a varnish occurs at a prepreg step. The problem with the method of incorporating yarns of a thermoplastic resin as marginal portions is that this method can be applied only to a special woven fabric, since the general step of heat cleaning for producing a glass fiber woven fabric cannot be carried out.
Further, it has been proposed to apply a hot-melt adhesive to the marginal portion of a glass fiber woven fabric for overcoming the above problems. Since, however, a glass fiber woven fabric is heated around a temperature of 150.degree. C. in a prepreg step while the hot-melt adhesive contains a solvent, warp yarns of the marginal portion ravel under some conditions to cause a trouble of being caught in a roller of a prepreg apparatus. Further, there is another problem: The marginal portions to which the hot-melt adhesive has been applied are thicker to some extent, and when the produced prepreg is cut to a predetermined size and stacked, the prepreg stack has a larger thickness in the marginal portions than in the central portion, which thickness difference hinders the automation of a lamination step.

Raveling-preventing agent for glass fiber woven fabric, and glass fiber woven fabric to which the agent is applied


Techniques are provided for client application authentication and include receiving a request to authenticate an application and, based on the received request to authenticate the application, sending a request to perform a push communication, including a short-term shared key, to a digital distribution system, wherein the digital distribution system is a distribution source of the application. The digital distribution system attempts to send the push communication including the short-term shared key to the application. The techniques may proceed by receiving a request for resources from the provider client application and determining whether the application has the short-term shared key. When it is determined that the application has provided the short-term shared key, the requested resources to the application may be provided, otherwise, the requested resources may be denied.

Many companies and individuals build mobile applications for devices such as tablets and smart phones. This software is often distributed by Google Play Store or Apple Store, but it can also be downloaded from other sources. Many of these applications can and must access back-end services, sensitive information, etc. Legitimate applications with legitimate users (e.g., logged-in, including by use of multi-factor authentication) accessing back-end services and sensitive information is not an issue. Issues arise, however, because these applications can also be "spoofed", meaning that a nefarious actor can build software that appears to be the legitimate software. The nefarious software may then be able to access these back-end services, sensitive data, etc. The back-end service will usually have no way to determine whether the software making a call to access services or data is a legitimate application or a nefarious actor. A form of this problem occurs when a legitimate user believes she is using a legitimate application, but the application is spoofing the original provider client application. As such, when the user logs into the nefarious or spoofing application, the provider will provide the nefarious application all of the access the user would be provided if she were using the legitimate application.
One security measure to combat these nefarious actors is an application key. The issue with application keys is that the original software can be decompiled, and the nefarious actor can then get access to or mimic the application key. The nefarious or spoofing software can then access that which should be restricted to the legitimate software (back-end services, sensitive information, etc.). Thus, the application key does not provide the protections needed.
The techniques described herein address those issues.
The approaches described in this section are approaches that could be pursued, but not necessarily approaches that have been previously conceived or pursued. Therefore, unless otherwise indicated, it should not be assumed that any of the approaches described in this section qualify as prior art merely by virtue of their inclusion in this section.

Application authenticity verification in digital distribution systems


The present invention relates to a wireless communication system, and more specifically to a method and an apparatus for inter-cell interference coordination for a transmission point group. The method for carrying out an interference coordination in a wireless communication system according to one embodiment of the present invention comprises a step for exchanging interference coordination messages between transmission point groups, wherein one transmission group comprises a plurality of transmission points, and the interference coordination message can comprises interference coordination information about each individual transmission point unit within the one transmission point group, and interference coordination information about the overall transmission point unit within the one transmission point group.

FIG. 1 is a diagram of a heterogeneous network wireless communication system 100 including a macro base station and a micro base station. In this specification, a terminology of a heterogeneous network means a network in which the macro base station 110 and the micro base stations 121/122 co-exist although an identical Radio Access Technology (RAT) is used.
The macro base station 121 means a general base station of a wireless communication system having a wide coverage and high transmit power. The macro base station 110 may also be named a macro cell.
For instance, the micro base station 121/122 can be named a micro cell, a pico cell, a femto cell, a home eNB (HeNB), a relay, or the like. The micro base station 121/122 is a small version of the macro base station 110 and can operate independently in a manner of performing most of functions of the macro base station. The micro base station is a sort of base stations installed (overlay) in an area covered by the macro base station or the base stations installable (non-overlay) in a radio shadow area where the macro base station is not able to cover. Compared to the macro base station 110, the micro base station 121/122 can accommodate small numbers of user equipments with a narrower coverage and lower transmit power.
A user equipment (hereinafter called a macro UE) 131 may be directly served from the macro base station 110 and a user equipment (hereinafter called a micro UE) 132 may be served from the micro base station 122 as well. In some cases, the user equipment 132 existing in the coverage of the micro base station 122 may be served from the macro base station 110.
If a user equipment served by a macro base station is adjacent to a micro base station, a downlink signal, which is received by a macro user equipment from the macro base station, may be interfered by interference occurred due to a strong downlink signal from the micro base station. Or, a user equipment served by the micro base station may be significantly interfered by interference occurred due to a downlink signal of the macro base station. as mentioned in the foregoing description, if one cell is significantly interfered by a neighboring cell, inter-cell interference coordination (ICIC) for mitigating/eliminating interference can be performed in a manner that the neighboring cell restricts transmission of the neighboring cell in a part of resource regions (e.g., a part of subframes and/or a part of frequency bands).

Method and apparatus for inter-cell interference coordination for transmission point group


Retrieving content in an Internet Protocol version 6 (IPv6) network may be provided. A lookup request associated with content may be received from a network node at a server having a mapping database. A response having an ordered list of more than one IPv6 addresses may be generated. The ordered list of the more than on IPv6 addresses may include IPV6 prefixes. Each of the more than one IPv6 addresses may include a first portion having a content identifier and a second portion having an indication of a location of the content. The response may be transmitted to the network node.

In a traditional IP network, such as an IPv4 network, the mapping database system, such as the DNS has to use a series of redirections, lookup tables, protocol formats and the like that have been constructed over time due to the specific restrictions in place (for example because of the use of IPv4 and the lack of IP addresses). The mapping database in such a network is used to route towards a particular host device, rather than content, that is associated with a fully qualified domain name.

Mapping database system for use with content chunks and methods of routing to content in an IP network


A data transfer unit (13) is provided for use in a clock swapping system which controls data transfer with a data transmission permit signal (rwo) and data reception permit signal (rro). The data transfer unit (13) includes a data latch (21) which latches transfer data in time with a transmission enable signal (ewi) and from which the data is read in time with a reception enable signal (eri), a first FR-FF circuit (31) which delays the transmission enable signal (ewi) for at least one period of a transmission clock (ckw), and a third SR-FF circuit 33 which delays the reception enable signal (eri) for a period of a reception clock (ckr). In the data transfer unit (13), a signal latched by the first SR-FF circuit (31) is latched a series of two times in time with the reception clock (ckr) to generate the reception permit signal (rro) and a signal latched by the third SR-FF circuit (33) is latched a series of two times in time with the transmission clock (ckw) to generate the transmission permit signal (rwo). Thus, the data transfer unit (13) can always assure stable data transfer by eliminating influence of a metastable state, if any.

1. Field of the Invention
The present invention relates to a data transfer unit and method, which permit data transfer between two systems operating on clocks asynchronous with each other.
This application claims the priority of the Japanese Patent Application No. 2002-269047 filed on Sep. 13, 2002, the entirety of which is incorporated by reference herein.
2. Description of the Related Art
For data transfer between two systems operating on clocks asynchronous with each other, one of the systems has to use the clock for the other system while the other system has to use the clock for the one system. Conventionally, this swapping between clocks is attained by accommodating a difference in timing between the clocks in an FIFO register or RAM or by generating a new clock for synchronization and transferring data synchronously with the new clock. However, the former method needs the FIFO register or RAM, which leads to an increased scale of circuit. Also, the latter method makes it necessary to input clock ratio information, timing adjusting parameter information or the like and provide a circuit which generates a clock for synchronization timing, which also leads to an increased circuit scale.
Further, the above clock swapping is attained by detecting an enable signal for data to be sent in time with a clock for a receiving end and transfer the data in time with the enable-signal detection. This method can be accomplished with an extremely small increase of the circuit scale but it is not possible unless the clock for the receiving end is sufficiently earlier than the clock for the sending end.
To solve the above problems, there has so far been proposed a system in which a data transmission permit signal and data reception permit signal are generated and the clock swapping for data transfer is done in response to the permit signals as shown in FIG. 1. The conventional clock swapping system shown in FIG. 1 will be described below.
As shown, in the conventional clock swapping system, generally indicated with a reference 100, there is provided between a data-transmission source (will be referred to as "transmitter 101" hereunder) and a data-transmission destination (will be referred to as "receiver 102" hereunder) a data transfer unit 103 which transfers data from the transmitter 101 to the receiver 102.
The transmitter 101 operates on a clock of a predetermined frequency (transmission clock ckw). The transmitter 101 outputs data on a predetermined bus width from a data output terminal thereof. For data transfer, the transmitter 101 sends transmission data dwi to the data transfer unit 103 synchronously with the transmission clock ckw.
For the data transfer, the transmitter 101 outputs also a transmission enable signal ewi indicating a transmission timing of the transmission data dwi transferred on a bus to the data transfer unit 103 synchronously with the transmission data dwi. The transmission enable signal ewi is represented by a binary signal having either of two values: H (high) and L (low) synchronous with the transmission clock ckw. The transmission enable signal ewi takes the value H when the transmission data dwi is being transferred from the transmitter 101 to the data transfer nit 103, and the value L when the transmission data dwi is not being transferred so.
The transmitter 101 receives, from the data transfer unit 103, a transmission permit signal rwo permitting to output the transmission data dwi. The transmission permit signal rwo is represented by a binary signal having either of two values: H (high) and L (low) synchronous with the transmission clock ckw. When the transmission permit signal rwo takes the value H for one clock, the transmitter 101 sends one word of the transmission data dwi to the data transfer unit 103 synchronously with the transmission clock ckw. While the transmission permit signal rwo is taking the value L, the transmitter 101 will not send the transmission data dwi and transmission enable signal ewi.
The receiver 102 operates on the transmission clock ckw and asynchronous clock (reception clock ckr). The receiver 102 is supplied at a data input terminal thereof with data on a predetermined bus width. For data transfer, the receiver 102 receives reception data dro synchronous wit a reception clock ckr from the data transfer unit 103.
The receiver 102 outputs a reception enable signal eri indicating a reception timing of the reception data dro being transferred on the bus to the data transfer unit 103 synchronously with the reception clock ckr. The reception enable signal eri is represented by a binary signal taking either of two values: H (high) and L (low) synchronous with the reception clock ckr. The reception enable signal eri takes the value H when the reception data dro is being transferred from the data transfer unit 103 to the receiver 102, and the value L when the reception data dro is not being transferred so.
The receiver 102 receives a reception permit signal rro permitting to input the reception signal dro is permitted from the data transfer unit 103. The reception permit signal rro is represented by a binary signal taking either of two values: H (high) and L (low) synchronous with the reception clock ckr. During a period for which the reception permit signal rro takes the value H, the receiver 102 can receive one word of the reception data dro from the data transfer unit 103 synchronously with the reception clock ckr. While the reception permit signal rro is taking the value L, the receiver 102 will not receive the reception data dro and send the reception enable signal eri.
When the transmission enable signal ewi takes the value H, the data transfer unit 103 receives one word of transmission data dwi and latches the data internally. Also, when the reception enable signal eri takes the value H, the receiver 102 reads one word of data latched in the data transfer unit 103.
The data transfer unit 103 is supplied with the transmission enable signal ewi from the transmitter 101, and the reception enable signal eri from the receiver 102. Also, the data transfer unit 103 outputs the transmission permit signal rwo to the transmitter 101 and the reception permit signal rro to the receiver 102.
In the above clock swapping system 100, there are cyclically done operations (S1) to (S4) as will be described below. It should be noted that when the power is supplied or when data transfer is started upon reception of an instruction for starting the data transfer, the data transfer unit 103 supplies an H-level transmission permit signal rwo to the transmitter 101 and L-level reception permit signal rro to the receiver 102.
(S1) First, upon reception of the H-level transmission permit signal rwo from the data transfer unit 102, the transmitter 101 supplies one word of the transmission data dwi to the data transfer unit 103. At this time, the transmitter 101 sets the level of the transmission enable signal ewi to H for one clock (transmission clock ckw) synchronously with the transfer of the transmission data dwi.
(S2) Next, upon reception of the H-level transmission enable signal ewi from the transmitter 101, the data transfer unit 103 supplies an H-level transmission permit signal rwo to the transmitter 101 and H-level reception permit signal rwo to the receiver 102. It should be noted that at this time, the data transfer unit 103 will take a pause of more than one period of the transmission clock ckw between a time when the transmission enable signal ewi is set to H (at the leading edge of the transmission enable signal ewi, for example) and a time when the reception permit signal rro is set to H (at the leading edge of the reception permit signal rro, for example). This is intended for assuring that storage of the transmission data dwi from the transmitter 101 into the data transfer unit 103 will positively be completed.
(S3) Upon reception of the H-level reception permit signal rro from the data transfer unit 103, the receiver 102 reads one word of the reception data dro from the data transfer unit 103. At this time, the receiver 102 sets the reception enable signal eri to H for one clock (reception clock ckr) synchronously with the transfer of the reception data dro.
(S4) Next, upon reception of the H-level reception enable signal eri from the receiver 102, the data transfer unit 103 supplies an L-level reception permit signal rro to the receiver 102 and H-level transmission permit signal rwo to the transmitter 101. It should be noted that at this time, the data transfer unit 103 will take a pause of more than one period of the reception clock ckr between a time when the reception enable signal eri is set to H (at the leading edge of the reception enable signal eri, for example) and a time when the transmission permit signal rwo is set to H (at the leading edge of the transmission permit signal rwo, for example). This is intended for assuring that reading of the reception data dro by the receiver 102 from the data transfer unit 103 will positively be completed.
The data transfer unit 103 is internally constructed as will be described below:
As shown in FIG. 1, the data transfer unit 103 includes a data latch 111 and a timing control circuit 112.
The data latch 111 operates synchronously with the transmission clock ckw and latches one word of the transmission data dwi on the bus when the transmission enable signal ewi has the value H. Also, when the reception enable signal eri is set to H, data latched in the data latch 111 is read for one word by the receiver 102.
As shown in FIG. 2, the timing control circuit 112 includes first to fourth SR flip-flop (SR-FF) circuits 121 to 124, first and second D flip-flop (D-FF) circuits 125 and 126, first and second OR circuits 127 and 128, first and second inversion circuits 129 and 130, and first and second AND circuits 131 and 132.
The first SR-FF circuit 121 is supplied at a set terminal (set) thereof with transmission enable signal ewi from the transmitter 101, and at a reset terminal (rst) with output signal from the first D-FF circuit 125. The first SR-FF circuit 121 is supplied at a clock terminal thereof with the transmission clock ckw.
The second SR-FF circuit 122 is supplied at a set terminal (set) thereof with output signal from the first D-FF circuit 125, and at a reset terminal (rst) with output signal from the third SR-FF circuit 123. The second SR-FF circuit 122 is supplied at a clock terminal thereof with the reception clock ckr.
The third SR-FF circuit 123 is supplied at a set terminal (set) thereof with the reception enable signal eri from the receiver 102, and at a reset terminal (rst) with output signal from the second D-FF circuit 126. The third SR-FF circuit 123 is supplied at a clock terminal thereof with the reception clock ckr.
The fourth SR-FF circuit 124 is supplied at a set terminal (set) thereof with output signal ewi from the second D-FF circuit 126, and at a reset terminal (rst) with output signal from the first SR-FF circuit 121. The fourth SR-FF circuit 124 is supplied at a clock terminal thereof with the transmission clock ckw.
The first D-FF circuit 125 is supplied at an input terminal (d) thereof with output signal from the first SR-FF circuit 121, and at a clock terminal with the reception clock ckr.
The second D-FF circuit 126 is supplied at an input terminal (d) thereof with output signal from the third SR-FF circuit 123, and at a clock terminal with the transmission clock ckw.
The first OR circuit 127 is supplied at one input terminal thereof with output signal from the first D-FF circuit 125, and at the other input terminal with output signal from the second SR-FF circuit 122. The second OR circuit 128 is supplied at one input terminal thereof with output signal from the second D-FF circuit 126, and at the other terminal with output signal from the fourth SR-FF circuit 124.
The first inversion circuit 129 is supplied at an input terminal thereof with output signal from the third SR-FF circuit 123, and the second inversion circuit 130 is supplied at an input terminal thereof with output signal from the first SR-FF circuit 121.
The first AND circuit 131 is supplied at one input terminal thereof with output signal from the first inversion circuit 129, and at the other input terminal with output signal from the first OR circuit 127. The second AND circuit 132 is supplied at one input terminal thereof with output signal from the second inversion circuit 130, and at the other input terminal with output signal from the second OR circuit 128.
In the timing control circuit 112 connected as above, output signal from the first AND circuit 131 is supplied as reception permit signal rro to the receiver 102, and output signal from the second AND circuit 131 is supplied as transmission permit signal rwo to the transmitter 101.
FIGS. 3 and 4 are timing diagrams of various signals when the timing control circuit constructed as above is used in the clock swapping system. FIG. 3 is a timing diagram when ckw<ckr, and FIG. 4 is a timing diagram when ckw>ckr. It should be noted that in both FIGS. 3 and 4, the reference "A" indicates output signal from the first SR-FF circuit 121, "B" indicates output signal from the first D-FF circuit 125, "C" indicates output signal from the third SR-FF circuit 123, and "D" indicates output signal from the second D-FF circuit 126.
In the conventional clock swapping system 100 which controls data transfer with the data transmission and reception permit signals as above, operations are done by repeating a sequence from issue of transmission permit signal rwo, storage of transmission data dwi, issue of reception permit signal rro to reading of reception data dro.
Therefore, the conventional clock swapping system 100 permits data transfer between two systems acting with clocks asynchronous with each other without having to use any large-capacity FIFO, RAM, etc. and whatever the ratio between the transmission and reception clocks ckw and ckr is.
The first D-FF circuit 125 is put into action at the leading edge of the reception clock ckr. However, a signal latched by the first D-FF circuit 125 is a one having been latched by the first SR-FF circuit 121 at the leading edge of the transmission clock ckw. Therefore, the time from latching of the transmission enable signal ewi by the first SR-FF circuit 121 until a next reception clock ckr rises will possibly be extremely short. In case the latching interval is so short, a so-called "metastable" phenomenon will possibly take place, resulting in an unstable operation of a downstream latch circuit (first D-FF circuit 125). Also, the second D-FF circuit 126 may possibly incur such a "metastable" phenomenon.


A CMOS integrated circuit (e.g., an SRAM or a DRAM) is partitioned into a core block, a peripheral block, and a retention block. The core block includes circuits (e.g., memory cells) that are powered on at all times and is coupled directly to power supply and circuit ground. The peripheral block includes circuits that may be powered on or off and are coupled to the power supply via a head switch and/or to circuit ground via a foot switch. The switches and the core block may be implemented with high threshold voltage (high-Vt) FET devices to reduce leakage current. The peripheral block may be implemented with low-Vt FET devices for high-speed operation. The retention block includes circuits (e.g., pull-up devices) that maintain signal lines (e.g., word lines) at a predetermined level so that the internal states of the core block are retained when the peripheral block is powered off.

I. Field
The present invention relates generally to data communication, and more specifically to techniques for reducing leakage current in complementary metal oxide semiconductor (CMOS) circuits.
II. Background
Integrated circuit (IC) fabrication technology continually improves and, as a result, the size of transistors continues to shrink. This enables more transistors and more complicated circuits to be fabricated on an IC die or, alternatively, a smaller die to be used for a given circuit. Smaller transistor size also supports faster operating speed and provides other benefits.
For CMOS technology, which is widely used for digital circuits and some analog circuits, a major issue with shrinking transistor size is standby power. A smaller transistor geometry results in higher electric field, which stresses a transistor and causes oxide breakdown. To decrease the electric field, a lower power supply voltage is often used for smaller geometry transistors. Unfortunately, the lower power supply voltage also increases the delay of the transistors, which is undesirable for high-speed circuits. To reduce the delay and improve operating speed, the threshold voltage (Vt) of the transistors is reduced. The threshold voltage determines the voltage at which the transistors turn on. However, the lower threshold voltage and smaller transistor geometry result in higher leakage current, which is the current passing through a transistor when it is turned off.
Leakage current is more problematic as CMOS technology scales smaller. This is because leakage current increases at a high rate with respect to the decrease in transistor size. Moreover, leakage current is a major issue for certain applications such as portable devices (e.g., cellular phone and portable computer). Leakage current consumes power and reduces standby time for portable devices that use battery power.
Reducing leakage current without sacrificing too much performance is one of the major challenges in CMOS designs, especially as IC technology scales down to 90 nm (nanometer) and smaller. One common method of combating high leakage current in large CMOS circuit designs is to cut off power to a CMOS circuit when it is turned off. Power may be cut off with a head switch, a foot switch, or both. A head switch is a switch placed between a power supply and the CMOS circuit. A foot switch is a switch placed between the CMOS circuit and circuit ground.
A dual-Vt CMOS technology allows for fabrication of both low threshold voltage (low-Vt) and high threshold voltage (high-Vt) field effect transistor (FET) devices on the same IC die. Since speed is not critical for head and foot switches, these switches may be implemented with high-Vt FET devices to reduce leakage current. The CMOS circuit is implemented with low-Vt FET devices for high-speed operation. During normal operation, the switches are turned on and the CMOS circuit operates with the speed advantage of the low-Vt FET devices. In a standby mode, which is also referred to as a sleep mode, the switches are turned off and the CMOS circuit is disabled. Since the leakage current of a high-Vt FET device may be as much as 10 to 100 times less than the leakage current of a low-Vt FET device, leakage current of the CMOS circuit is reduced by the use of high-Vt FET devices for the switches.
The method described above for reducing leakage current (i.e., with high-Vt FET devices for the switches and low-Vt FET devices for the CMOS circuit) is adequate for some CMOS circuits. However, disconnecting the power supply with a head switch and/or circuit ground with a foot switch may be detrimental for certain CMOS circuits. One such CMOS circuit is a static random access memory (SRAM) with memory cells implemented with FET devices. For the SRAM, disconnecting the power supply and/or circuit ground causes the FET devices to float, which may cause the memory cells to lose their internal states. Consequently, data may be lost when the SRAM is placed in the standby mode.
There is therefore a need in the art for techniques to reduce leakage current for CMOS circuits such as SRAM.

Leakage current reduction for CMOS memory circuits


An electromechanical relay employing a movable first permanent magnet and a nearby third electromagnet is disclosed. The movable first magnet is permanently magnetized and has at least a first end. The third electromagnet, when energized, produces a third magnetic field which is primarily perpendicular to the magnetization direction of the first movable magnet and exerts a magnetic torque on the first magnet to force the first magnet to rotate and closes an electrical conduction path at the first end. Changing the direction of the electrical current in the third electromagnet changes the direction of the third magnetic field and thus the direction of the magnetic torque on the first magnet, and causes the first magnet to rotate in an opposite direction and opens the electrical conduction path at the first end. Multiple magnets can be stacked together to form multi-pole-multi-throw relays. Latching and non-latching types of relays can be formed by appropriately using soft and permanent magnets as various components.

Relays are electromechanical switches operated by a flow of electricity in one circuit and controlling the flow of electricity in another circuit. A typical relay includes an electromagnet with a soft iron bar, called an armature, held close to it. A movable contact is connected to the armature in such a way that the contact is held in its normal position by a spring. When the electromagnet is energized, it exerts a force on the armature that overcomes the pull of the spring and moves the contact so as to either complete or break a circuit. When the electromagnet is de-energized, the contact returns to its original position.
Latching relays are the types of relays which can maintain closed and open contact positions without energizing an electromagnet. Short current pulses are used to temporally energize the electromagnet and switch the relay from one contact position to the other. An important advantage of latching relays is that they do not consume power (actually they do not need a power supply) in the quiescent state.
Conventional electromechanical relays have traditionally been fabricated one at a time, by either manual or automated processes. The individual relays produced by such an "assembly-line" type process generally have relatively complicated structures and exhibit high unit-to-unit variability and high unit cost. Conventional electromechanical relays are also relatively large when compared to other electronic components. Size becomes an increasing concern as the packaging density of electronic devices continues to increase.
Two forms of conventional latching relays are described in the Engineers' Relay Handbook (Page 3-24, Ref. [1]). A permanent magnet supplies flux to either of two permeable paths that can be completed by an armature. To transfer the armature and its associated contacts from one position to the other requires energizing current through the electromagnetic coil using the correct polarity. One drawback of these traditional latching relay designs is that they require the coil to generate a relatively large reversing magnetic field in order to transfer the armature from one position to the other. This requirement mandates a large number of wire windings for the coil, making the coil size large and impossible or very difficult to fabricate other than using conventional winding methods.
U.S. Pat. No. 5,818,316 issued to Shen et al. described a switch having two magnetizable conductors in which the first conductor is permanently magnetized and the second conductor is switchable in response to a magnetic field applied thereto.
U.S. Pat. No. 6,469,602 B2 issued to Ruan et al. described a relay operated by providing a cantilever sensitive to magnetic fields such that the cantilever exhibits a first state corresponding to the open state of the relay and a second state corresponding to the closed state of the relay.
U.S. Pat. No. 6,124,650 issued to Bishop et al. disclosed a relay employing square-loop latchable magnetic material having a magnetization direction capable of being changed in response to exposure to an external magnetic field. The magnetic field is created by a conductor assembly. The attractive or repulsive force between the magnetic poles keeps the switch in the closed or open state.
Each of the aforementioned relays, though providing a unique approach to make latching electromechanical relays, has drawbacks and limitations. Some of them may require large current for switching, and some may require precise relative placement of individual components. These drawbacks and limitations can make manufacturing difficult and costly, and hinder their value in practical applications.
Accordingly, it would be highly desirable to provide an easily switchable electromechanical relay which is also simple and easy to manufacture and use.
It is a purpose of the present invention to provide a new and improved electromechanical relay which can be easily configured as latching or non-latching types.
It is another purpose of the present invention to provide a new and improved multi-pole multi-throw electromechanical relay.

Coupled electromechanical relay and method of operating same


A web page distributing server receives a transmission request for a web page from a terminal device, and transmits, to the terminal device, web page data to display the entire web page in response to the transmission request. The web page distributing server transmits, to the terminal device, a program that causes the terminal device to achieve a completion determination function to determine whether or not a browser of the terminal device has completed reading of data necessary to display a position containing a specific part in the web page and an intermediate movement function to move a position of a browser screen to a specific scroll position which is a position where the specific part is contained in the browser screen in response to the determination by the completion determination function that the reading has been completed.

Link functions of a web page involve a display transition to the header part of a linked page, and a display transition to a specific part other than the header part of the page. According to conventional technologies, when a transition is made to the specific part of a page, a browser screen is located to the header part of the page immediately after the page transition, the display of the part having undergone completion of reading in sequence from the header part of the page is started, and then the browser screen is transitioned to the location where the specific part can be displayed upon completion of reading of the entire page, and thus the specific part is presented to a user.
In this case, when the display transitions to the specific part of a linked page, there is a case such that all pieces of information contained in the page should be transmitted.
In the case of, for example, an answer page for a questionnaire survey, if only a part is confirmed, the reliability of the answer details decreases, and in the case of, for example, an application page for a credit card, all fields are provided in an editable manner and require inputting, and input details must be checked. Moreover, in the case of, for example, a listing page of various terms and conditions, if only a part is presented, a misunderstanding may occur.
Relevant conventional technologies are disclosed in the following Patent Literatures 1 and 2.

Web page distributing server, web page distributing method, and storage medium


A drive system for driving and/or extracting an elongate member. The drive system comprises a piston drive assembly, a hydraulic system, and a vibration drive assembly. The piston drive assembly comprises a piston member, and the piston member engages the elongate member. The hydraulic system is operatively connected to the piston drive assembly to apply a drive force to the piston member. The vibration drive assembly generates a vibratory force. The vibration drive assembly is operatively connected to the piston drive assembly. The drive system operates in a first mode in which the drive force and the vibratory force are applied to the piston member along a drive axis.

For certain construction projects, rigid members, such as piles, anchor members, caissons, sheet pile barriers, and mandrels for inserting wick drain material, must be placed into the earth. The term "piles" will be used herein to refer to the rigid members typically driven into the earth during construction projects. It is well-known that such rigid members may often be driven into or extracted from the earth without excavation by applying a driving or extracting force on an upper end of the pile.
To drive or extract a pile, a driving force is typically applied to the pile along a longitudinal axis A of the pile. The driving force may be created in various ways. A drop hammer comprises a ram member that is repeatedly raised and dropped such that the impact of the ram member drives the pile into the earth. A diesel hammer comprises a ram member that compresses and ignites fuel between the ram member and the pile; the impact of the ram member drives the pile, while expansion of the ignited fuel both drives the pile into the earth and raises the drop hammer for the next impact. A hydraulic drive system uses a hydraulic ram to force or crowd the pile into the earth. A crane may be used to apply an extraction force on a pile through a cable.
In addition, vibratory forces may be applied to the pile. Vibratory forces are also applied along the longitudinal axis A of the pile, typically in combination with a passive driving force created by the weight of the vibration equipment on top of the pile. The combination of the passive driving force and the vibratory forces is often sufficient to drive a pile in certain soil types. Typically, a suppressor is used to isolate support equipment such as a crane or the like from the vibratory forces.
Attempts have been made to combine vibratory forces with active driving forces such as a hydraulic drive system. U.S. Pat. Nos. 6,039,508 and 6,431,795 to White disclose systems and methods for inserting wick drain material comprising a bottom drive system that combines a vibratory device with a gear drive to drive a mandrel supporting the wick drain mater. The gear drive crowds the mandrel into the earth, and the vibratory device is operated to assist the gear drive under some soil conditions.
The need exists for improved vibratory pile driving systems and methods.

Vibratory pile driving systems and methods


A fluid distribution system for controlling the operation of a swimming pool cleaning device includes a housing having an inlet for receiving a supply of pressurized fluid, a plurality of outlet openings and a valve chamber between the inlet and outlet openings. The housing has at least one compound cylinder having two portions with different bore diameters for slideably accommodating therein a mating stepped piston. Each portion of the compound cylinder fluidly communicates with pressurized water in the valve chamber via associated fluid pathways. The larger cylinder is vented by a relief valve actuated by a fluid driven cam that periodically opens and closes the relief valve. When the relief valve is closed, the pressure within the large cylinder pushes the piston to a first position which effects the opened/closed status of a port, e.g., allowing one of the outlets to communicate with the pressurized water in the valve chamber. When the relief valve is opened, the pressure within the larger cylinder is reduced, allowing the pressure in the smaller cylinder to push the piston to a second position which effects the opened/closed status of the port and/or opens another port to allow the pressurized fluid to be discharged through another outlet.

U.S. Pat. Nos. 6,090,219 and 6,365,039 and International Patent Publication No. WO 99/33582 disclose swimming pool cleaners adapted to rise proximate to a water surface of a pool for removing floating debris therefrom and to descend proximate to a wall surface of the pool for removing debris therefrom (see also U.S. Pat. Nos. 6,039,886 and 6,387,250 and International Patent Publication No. WO 99/34077). These cleaners utilize fairly complicated and/or complex mechanisms for controlling their water surface cleaning and wall surface cleaning operations. Accordingly, there is a need for a pool cleaner equipped with an enhanced control mechanism for controlling the operation of the cleaner. There is also need for other improvements for enhancing the operation of the pool cleaner.

Fluid distribution system for a swimming pool cleaning apparatus


Provided is a bit holder device which is capable of driving a screw into a workpiece, while holding the screw having a groove in which a bit body is inserted, and which makes it possible to change the bit body without removing it from a chuck of an electric tool, etc.

A conventional bit holder device which holds a screw, etc. with retaining a bit body inserted in the groove on the head of the screw, etc. to facilitate a job of tightening, driving into a workpiece, or the like of the screw is disclosed in, for example, JP-A-2000-246658.
What is disclosed in that publication consists of a cylindrical body fitted on a bit body attached to an electric tool, and the cylindrical body is provided with holding means (a magnet) for holding a screw with the bit body inserted in the groove of its head.
The use of the cylindrical body has, however, makes the attachment and detachment of the bit and cylindrical bodies cumbersome, since two jobs, that is, the job of removing the bit body from the chuck of the electric tool and the job of removing the cylindrical body from the bit body are required for changing the bit body and attaching the cylindrical body to another bit body.
A bit holder device as disclosed in German Patent Publication DE10148943A1 is known as a type in which the bit body is removably held by a holder body having a shank in its rear portion. The device described in the German Patent Publication has, however, a drawback that the cylindrical body cannot be removed from the holder body.    Patent Literature 1: JP-A-2000-246658    Patent Literature 2: German Patent Publication DE10148943A1

Abstract: A bit holder device facilitating the attachment and detachment of a cylindrical body is also provided.

Abstract: A bit holder device for driving a screw, while holding the screw against detachment from a bit body with retaining a state where an end of the bit body is inserted in a groove on a head of the screw, has a cylindrical cover member removably fitted about the bit body from the end of the bit body, the cover member has an end including a magnetic attracting portion for magnetically attracting the head of the screw, and the bit body protrudes from the end of the cover member.


Systems and methods for conducting convenient and secure mobile transactions between a payment terminal and a mobile device, e.g., in a fueling environment, are disclosed herein. In some embodiments, the payment terminal and the mobile device conduct a mutual authentication process that, if successful, produces a session key which can be used to encrypt sensitive data to be exchanged between the payment terminal and the mobile device. Payment and loyalty information can be securely communicated from the mobile device to the payment terminal using the session key. This can be done automatically, without waiting for the user to initiate a transaction, to shorten the overall transaction time. The transaction can also be completed without any user interaction with the mobile device, increasing the user's convenience since the mobile device can be left in the user's pocket, purse, vehicle, etc.

A number of mobile payment systems have been developed in which a mobile device can be used to pay for goods or services at a payment terminal. In some systems, the mobile device does not communicate directly with the payment terminal. Rather, the transaction is conducted between a mobile device payment infrastructure and a merchant payment infrastructure (e.g., cloud-to-cloud). Integrating these complex and widely-divergent infrastructures, however, can often be cost-prohibitive.
Other systems involve direct communication between the mobile device and the payment terminal. In such systems, sensitive user data such as payment and loyalty information is transmitted as cleartext, raising a number of security issues. For example, the sensitive user data can be intercepted by unscrupulous third parties. This can be of particular concern in fueling environments, where the payment terminal is often disposed in an unmanned, outdoor setting where there is an elevated risk of snooping or tampering. Users can be discouraged from using such systems for fear that the payment terminal may have been compromised.
Many existing mobile payment systems also require user interaction with the mobile device before, during, or after a transaction. For example, the user must retrieve the mobile device and launch a digital wallet application or otherwise interact with software executed on the mobile device to begin a transaction. The user must also hold the mobile device up to the payment terminal to place the mobile device in close proximity to the payment terminal.
Existing mobile payment systems can thus be unsecure and cumbersome or time consuming for the user, and a need exists for improved mobile payment systems.

Systems and methods for convenient and secure mobile transactions


A pick and place device includes a lift head and a build platform. Both the lift head and the build platform include flexible aprons. An item layer is constructed on the build platform and the lift head is moved into position over the build platform. By slipping the lift head apron under the layer while concurrently pulling from under the layer the build platform apron, support for the layer passes from the build platform to the lift head. The lift head then moves to a place site and the lift head apron is pulled from under the layer and the layer falls from the lift head onto the place site. Under one form of the device, the layer may be constructed directly upon the lift head apron and then moved to a place site and deposited thereat by pulling the lift head apron from thereunder.

The present invention relates generally to article manipulation, and particularly to manipulation of entire layers of items during palletizing operations.
A pallet is a standard support and carrier structure used in shipping. Pallets provide a support surface receiving items stacked for transport. Pallets include a space below the support surface receiving, for example, the tines of a forklift whereby the forklift lifts and moves the pallet with a stack of items thereon. Typically, items are boxes organized in layers upon the pallet. Efficient shipping of palletized items calls for efficient stacking of items on the pallet to minimize open space within the stack. Furthermore, by varying the orientation and/or pattern of items from layer to layer, a stable stack of items may be constructed upon a pallet. Accordingly, a variety of "box patterns" have emerged for efficient and stable packing together of items in item layers on a pallet. The standard pallet is used widely throughout the shipping industry and a variety of apparatus have evolved in relation to the standard pallet for stacking items upon pallets, i.e., for palletizing.
Thus, palletizing, as used herein, generally refers to a process of constructing a stack of items organized as layers on a pallet. The term palletizing as used herein, however, shall not be limited to stacking relative to a pallet, but shall include generally any stacking process relative to articles organized as stacked layers.
A common arrangement for palletizing uses a rigid planar "apron" to lift from below a layer of items. A layer might be built upon an apron or the apron might be positioned under the layer by sliding the apron between the layer and a supporting surface therebelow. Once positioned below a layer of items, the apron moves and places the item layer elsewhere, e.g., moves the item layer over a pallet or the top layer of a stack of item layers on a pallet. The palletizing device then blocks the layer against movement while the apron slides out from underneath the layer. In this manner, the apron moves and places an entire layer of items upon a pallet or upon the top layer of items on a pallet. Generally, an apron performs only palletizing operations because of the difficulty of inserting an apron between layers of an existing stack of items on a pallet. Unfortunately, use of such a rigid planar apron requires significant space adjacent the pallet stack to accommodate the apron as it is pulled from under the item layer.
One known prior palletizing device, available from the Matthews Conveyor Division, uses a "wrap-around apron" including a set of rollers positioned above a pallet. An item layer is constructed on the rollers and the pallet including any layers stacked thereon moves upward to a point just below the rollers. The item layer is then blocked against movement and the rollers are pulled out from underneath the item layer resting thereon. The item layer thereby drops onto the pallet or stack of item layers resting on the pallet. Unfortunately, this arrangement requires manipulation of the entire pallet and stack of item layers resting on the pallet to position the upper portion thereof just below the rollers and allow a new item layer to come to rest thereon as the rollers are pulled out from thereunder. Accordingly, the rollers follow a path out from underneath the new layer and then down, around, and underneath the entire pallet and stack of items resting thereon. This device is referred to as a "WR Series Palletizer."
U.S. Pat. No. 3,782,564 entitled Product Picking Stacker Crane System, filed Sep. 27, 1971 by Harold S. Burt, shows an overhead crane system transferring item layers from one stack to an adjacent stack. The system is a dual actuator system requiring separate vertical movement actuators and horizontal movement actuators operating in coordination.
U.S. Pat. No. 3,836,018 entitle Discrete Article Palletizing and De-Palletizing apparatus, filed Nov. 5, 1973 by George J. Dawson, et al shows a palletizing device including a top-picking engagement mechanism and a dual actuation drive system, i.e., a horizontal actuation system and a separate vertical actuation system. The illustrated apparatus moves item layers between a first station and a second station.
Thus, article manipulation in the context of palletizing generally requires relatively complex apparatus and associated complex control schemes. Devices using multiple actuators, e.g., gantry systems with x-y positioning of a load, result in relatively complex and expensive apparatus. Because such systems include separate actuation devices operating in different dimensions, e.g., separate devices for movement in an x dimension and a y dimension, such systems can cause abrupt transition in vertical or horizontal movement and thereby risk loss of a load. To avoid such abrupt transition in movement, elaborate coordination and control must be imposed upon the separate actuation devices to accomplish smooth transition in vertical and horizontal movement.
Thus, it would be desirable to provide a palletizing apparatus having a simplified structural architecture and a simplified control scheme for reduced overall cost and reduced overall complexity with a smooth transition in movement of loads.


The measuring device (1) comprises a scale graduation element (3) provided with a number of tracks (9, 13), a pick-up device (5) which comprises a number of sensing elements (4, 6) provided with sensors, which number corresponds to the number of tracks (9, 13), and also comprises a signal processing system (7). The tracks (9, 13) include an incremental track (9) and an absolute track (13). Both tracks are formed as a succession of strip-shaped parts (11, 15), each of which has a property which can be detected by the sensors of the sensing elements (4, 6). This property is dependent on the location on the scale graduation element (3). This property is preferably bivalent. In the signal processing system (7) signals originating from the sensing element (4) associated with the incremental track (9) and signals originating from the sensing element (6) associated with the absolute track (13) are combined. On the absolute track (13) the property is distributed in a pseudo-random fashion between the strip-shaped parts (15) so that the combination of signals for a pitch (17) of the incremental track (9) produces a specific value for each pitch (17). Consequently, the measurement value produced by the signal processing system (7) is absolute.

The invention relates to a measuring device for determining an absolute position of a movable element, comprising a scale graduation element with a number of tracks and a pick-up device which comprises a number of sensing elements which corresponds to the number of tracks, said sensing elements being provided with sensors and said tracks including an incremental track and an absolute track and being formed as a succession of strip-shaped parts, each of which has a property which can be detected by the sensors and which is dependent on the location on the scale graduation element, and also comprising a signal processing system for determining the absolute position of the movable element from a combination of, on the one hand, signals originating from the sensors of the sensing element associated with the absolute track and, on the other hand, signals originating from the sensors of the sensing element associated with the incremental track.
The invention also relates to a scale graduation element suitable for use in such a measuring device.
A measuring device of this kind is known from European Patent Application EP 0 246 404 A2. The cited Application describes a measuring device for determining the relative position of two objects, utilizing a scale graduation element in the form of a measuring ruler on which there are provided on the one hand an incremental graduation and on the other hand a graduation of reference marks whereto an absolute position is assigned. This has a drawback in that it is not possible to determine the absolute position without displacing the pick-up device at least as far as the next absolute reference mark. The sensing of the incremental track produces an absolute measure within a pitch, but the resolution of the determination of the absolute value on the measuring ruler is limited by the encoding of the reference marks and the minimum distance that can be achieved between these marks.

Measuring device for determining an absolute position of a movable element and scale graduation element suitable for use in such a measuring device


A glass-ceramic substrate for a magnetic disk suitable for use as a contact recording type magnetic disk includes alpha-cristobalite (alpha-SiO.sub.2) and lithium disilicate (Li.sub.2 O . 2SiO.sub.2) as main crystal phases. The ratio of alpha-cristobalite/lithium disilicate is within a range from 0.25 to 0.35, a grain diameter of crystal grains is within a range from 0.1 .mu.m to 1.0 .mu.m, surface roughness (Ra) of the substrate after polishing is within a range from 2 .ANG. to 10 .ANG. and abrasion resistance index (Aa) of the substrate is within a range from 5 to 15.

This invention relates to a magnetic disk substrate used for a bard magnetic disk recording device and, more particularly, to a magnetic disk substrate made of a glass-ceramic suitable for use as a contact recording type magnetic disk.
There is an increasing tendency for utilizing a personal computer for multiple media purposes and this tendency necessitates a hard magnetic disk device of a larger recording capacity. For this purpose, the bit number and track density of a magnetic disk must be increased and the size of a bit cell must be reduced for increasing a surface recording density. As for a magnetic head, it must be operated in closer proximity to the disk surface in conformity with the size reduction of the bit cell and, for this purpose, the contact recording system has been developed according to which recording is performed with the magnetic head being nearly in contact with the disk surface, and with the amount of lifting of the magnetic head from the disk surface being maintained below 0.023 .mu.m.
In such contact recording system, the magnetic disk is required to have the surface roughness (Ra) of 10 .ANG. or below in order to maintain the amount of lifting of the magnetic head below 0.025 .mu.m. Besides, the magnetic disk is required to have abrasion resistance which is sufficiently high for standing contact with the magnetic head.
Aluminum alloy has been conventionally used as a material of magnetic disk substrate. The aluminum alloy substrate, however, tends to produce a substrate surface having projections or spot-like projections and depressions during the polishing process due to defects inherent in the material. As a result, the aluminum alloy substrate is not sufficient in flatness. Further, since an aluminum alloy is a soft material, deformation tends to take place so that it cannot cope with the recent requirement for making the magnetic disk thinner and the requirement for high density recording because the disk tends to be deformed by contact with the head with resulting damage to the recorded contents.
As a material for overcoming this problem of the aluminum alloy substrate, known in the art are glass substrate for magnetic disks made of a chemically tempered glass such as a sodium lime glass (SiO.sub.2 --CaO--Na.sub.2 O) and alumino-silicate glass (SiO.sub.2 --Al.sub.2 O.sub.3 --Na.sub.2 O). This glass substrate, however, has the following disadvantages:
(1) Polishing is made after chemical tempering and so the tempered layer tends to cause instability in thinning the disk substrate. PA0 (2) Since the Na.sub.2 O ingredient is included as an essential ingredient in the glass, the film forming characteristic of the glass is deteriorated with the result that a surface coating processing becomes necessary for preventing eluting of the Na.sub.2 O ingredient. This prevents mass production of the product at a competitive cost.
Aside from the aluminum alloy substrate and chemically tempered glass substrate, known in the art are some substrate made of glass-ceramics. For example, Japanese Patent Application Laid-open No. 6-329440 discloses a glass-ceramic of a SiO.sub.2 --Li.sub.2 O--MgO--P.sub.2 O.sub.5 system which includes lithium disilicate (Li.sub.2 O . 2SiO.sub.2) and alpha-quartz (alpha-SiO.sub.2) as predominant crystal phases. This glass-ceramic is an excellent material in that the grain size of globular grains of alpha-quartz can be controlled but surface roughness (Ra) of a polished surface is within a range from 15 .ANG. to 50 .ANG.. This glass-ceramic cannot cope with the above described target surface roughness (Ra) of 10 .ANG. or below so that it cannot sufficiently cope with the above described tendency to lowering of the amount of lifting of a magnetic head necessitated by rapid increase in the recording capacity.
It is, therefore, an object of the invention to eliminate the above described disadvantages of the prior art substrates and provide a glass-ceramic substrate for a magnetic disk which is suitable for use as a contact recording type magnetic disk for coping with the tendency toward high recording density of a hard magnetic disk by having surface roughness (Ra) of 10 .ANG. or below and also having a high abrasion resistance.

Glass-ceramic substrate for a magnetic disk