A low cost, high speed WDM optical link which employs a circular array of VCSEL emitters directly coupled to a multi-mode fiber through which multiple simultaneously optical transmissions are sent to an optical detector comprising a circular array of RCPD detectors receiving the multiple simultaneous transmissions. The emitters and detectors within each array are fabricated with a double-absorber design which avoids position sensitivity related to the cavity standing wave and eliminates the need for in-situ cavity-mode adjustment. In addition, a coupled-cavity structure is presented to achieve passbands with flat tops and steep sides to approach the ideal square-shape photoresponse and to ensure proper channel alignment.

Not Applicable
The following publications which are referred to herein using a number in square brackets (e.g., [1]) are incorporated herein by reference.
[1] S. Y. Hu, J. Ko, E. R. Hegblom, and L. A. Coldren, xe2x80x9cMultimode WDM optical data links with monolithically-integrated multiple-channel VCSEL and photodetector arrays,xe2x80x9d IEEE J. Quantum Electron., vol. 34, pp. - - - , August 1998.
[2] S. Y. Hu, J. Ko, and L. A. Coldren, xe2x80x9cHigh-performance densely-packed vertical-cavity photonic integrated emitter arrays for direct-coupled WDM applications,xe2x80x9d IEEE Photon. Technol. Lett., vol. 10, pp.766-768, June 1998.
[3] S. Y. Hu, J. Ko, E. R. Hegblom, and L. A. Coldren, xe2x80x9cHigh-performance multiple-wavelength vertical-cavity photonic integrated emitter arrays for direct-coupled multimode optical links,xe2x80x9d Proc. CLEO""98 conference, San Francisco, Calif., May 3-8, 1998, paper no. CThK1, Invited.
[4] S. Y. Hu, S. Z. Zhang, J. Ko, J. E. Bowers, and L. A. Coldren, xe2x80x9c1.5 Gb/s/ch operation of multiple-wavelength vertical-cavity photonic integrated emitter arrays for low-cost WDM local-area networks,xe2x80x9d Electron. Lett., vol. 34, No. 8, pp. 768-770, April 1998.
[5] S. Y. Hu, J. Ko, O. Sjolund, and L. A. Coldren, xe2x80x9cOptical crosstalk in monolithically-integrated multiple-wavelength vertical-cavity laser arrays for multimode WDM local-area networks,xe2x80x9d Electron. Lett., vol. 34, No. 7, pp. 676-678, April 1998.
[6] S. Y. Hu, E. R. Hegblom, and L. A. Coldren, xe2x80x9cMultiple-wavelength top-emitting vertical-cavity photonic integrated emitter arrays for direct-coupled wavelength-division multiplexing applicationsxe2x80x9d Electron. Lett., vol. 34, No. 2, pp. 189-190, January 1998.
[7] L. A. Coldren, E. R. Hegblom, Y. A. Akulova, J. Ko, E. M. Strzelecka, and S. Y. Hu, xe2x80x9cVCSELs in ""98: What we have and what we can expect,xe2x80x9d SPIE Proceedings, San Jose, Calif., January 28-29, Vol. 3286, 1998.
[8] S. Y. Hu, E. R. Hegblom, and L. A. Coldren, xe2x80x9cMultiple-wavelength top-emitting vertical-cavity laser arrays for wavelength-division multiplexing applications,xe2x80x9d Proc. 10th IEEE LEOS annual meeting, San Francisco, Calif., Nov. 10-13, 1997, postdeadline paper PD1-6.
[9] S. Y. Hu, J. Ko, and L. A. Coldren, xe2x80x9cPie-shaped resonant-cavity InGaAs/InAlGaAs/InP photodetector arrays for direct-coupled wavelength demultiplexing applications,xe2x80x9d Proc. 10th IEEE LEOS annual meeting, San Francisco, Calif., Nov. 10-13,1997, Paper TuJ4.
[10] S. Y. Hu, J. Ko, and L. A. Coldren, xe2x80x9c1.55-xcexcm pie-shaped resonant-cavity photodetector arrays for direct-coupled wavelength demultiplexing applications,xe2x80x9d Electron. Lett., vol. 33, pp. 1486-1488, August 1997.
[11] S. Y. Hu, E. R. Hegblom, and L. A. Coldren, xe2x80x9cCoupled-cavity resonant photodetectors for high-performance wavelength demultiplexing applications,xe2x80x9d Appl. Phys. Lett., vol. 71, pp. 178-180, July 1997.
[12] S. Y. Hu, J. Ko, and L. A. Coldren, xe2x80x9cResonant-cavity InGaAs/InAlGaAs/InP photodetector arrays for wavelength demultiplexing applications,xe2x80x9d Appl. Phys. Lett., vol. 70, pp. 2347-2349, May 1997.
[13] E. C. Vail, G. S. Li, W. Yuen, and C. J. Chang-Hasnain, xe2x80x9cHigh performance and novel effects of micromechanical tunable vertical-cavity lasers,xe2x80x9d IEEE J. Select. Topic Quantum Electron., vol. 3, pp. 691-697, 1997.
[14] T. Wipiejewski, J. Ko, B. J. Thibeault, and L. A. Coldren, xe2x80x9cMultiple wavelength vertical-cavity laser array employing molecular beam epitaxial regrowth,xe2x80x9d Electron. Lett., vol. 32, pp. 340-342, 1996.
[15] D. L. Huffaker and D. G. Deppe, xe2x80x9cMultiwavelength, densely-packed 2xc3x972 vertical-cavity surface-emitting laser array fabricated using selective oxidation,xe2x80x9d IEEE Photon. Technol. Lett., vol. 7, pp. 858-860, 1996.
[16] W. Yuen, G. S. Li, and C. J. Chang-Hasnain, xe2x80x9cMultiple-wavelength vertical-cavity surface-emitting laser arrays,xe2x80x9d IEEE J. Select. Topic Quantum Electron., vol. 3, pp. 422-428, 1997.
[17] A. Fiore, Y. A. Akulova, E. R. Hegblom, J. Ko, and L. A. Coldren, xe2x80x9cpostgrowth tuning of cavity resonance for multiple-wavelength laser and detector arraysxe2x80x9d Proc. CLEO""98 conference, San Francisco, Calif., May 3-8, 1998, paper no. CThX3.
[18] H. Hasegawa, K. E. Forward, and H. Hartnagel, xe2x80x9cImproved method of anodic oxidation of GaAsxe2x80x9d, Electron. Lett., Vol.11, pp. 53-54, 1975.
[19] K. H. Hahn, M. R. T. Tan, Y. M. Houng, and S. Y. Wang, xe2x80x9cLarge area multitransverse-mode VCSELs for modal noise reduction in multimode fiber systems,xe2x80x9d Electron. Lett., vol. 29, pp. 1482-1483, 1993.
[20] C. A. Burrus and B. I. Miller, xe2x80x9cSmall-area double heterostructure AlGaAs electroluminescent diode sources for optical fiber transmission lines,xe2x80x9d Opt. Commun., vol. 4, pp. 307-309, 1971.
1. Field of the Invention
This invention pertains to device structures and simple packaging schemes to realize low-cost, yet high-performance, multimode wavelength-division multiplexing (WDM) optical data links.
2. Description of the Background Art
(a) Introduction
The demand for ever faster data transmission rates (a few Gb/s up to 100 Gb/s) has attracted considerable interest in the development of high-capacity optical data links for short-haul local-area networks and fiber-to-the-desktop applications. The majority of work to date has focused on one-dimensional parallel optical data links which utilize multimode fiber ribbons with a one-data-channel-per-fiber arrangement. However, the maximum aggregate data transmission rate is limited to about 2-3 gigabytes per second and the system configuration is costly and very complicated.
One definitive solution to the bandwidth problem is to take advantage of the extra-wide bandwidth of optical fibers by employing the wavelength-division multiplexing (WDM) configuration which can significantly expand the transmission capacity by having multiple data channels in each fiber. With WDM, however, the corresponding transmitter and receiver modules must be low cost to be attractive for emerging xe2x80x9cgigabytes-to-the-desktopxe2x80x9d applications. A problem with WDM is that any additional complexity in device fabrication and packaging technology can dramatically increase the manufacturing cost. The availability of such low-cost multiple-wavelength emitter and detector arrays is also a key issue for the realization of ultra-high-density multiple-layer digital versatile disk technology. Obviously, the vertical-cavity device structure is the ideal candidate for WDM configurations because the resonant wavelength can be easily varied and its fiber packaging is potentially low-cost.
(b) VCSEL Emitters in Optical Data Links
With the inherent advantages of its two-dimensional configuration, efficient fiber coupling, and on-wafer testing capability, VCSEL (Vertical-Cavity Surface-Emitting Laser) structures have remained the preferred candidate for free-space interconnects and optical fiber communication since inception. Within the last decade, there have been numerous advances in epitaxial technology, device design, and processing techniques such that the performance of VCSELs has been greatly improved. Currently, major accomplishments in VCSEL technology have been demonstrated in the 0.8-1.00 xcexcm wavelength regime, where VCSELs are being incorporated into many advanced optical systems as a high-performance and yet low-cost solution for short-distance communications.
VCSELs are the ideal laser structures for the implementation of wavelength-division multiplexing (WDM) systems because the lasing wavelength can be easily varied by adjustment of the cavity length. However, due to the difficulty of achieving convenient and high-reflectivity distributed-Bragg reflector (DBR) mirrors in the long-wavelength (1.3-1.55 xcexcm) regime, in-plane distributed feedback (DFB) laser arrays have been the traditional structures in long-haul WDM optical communications. On the other hand, It is difficult to make in-plane DFB lasers at 0.8-1.00 xcexcm for short-haul optical communications, and VCSEL technology at 0.8-1.00 xcexcm has matured to a point where it is possible to build VCSEL-based WDM optical data links for short-haul optical interconnects.
In recent years, micromechanically tunable VCSELs [13] and monolithically integrated multiple-wavelength VCSEL arrays [14]-[17] have been reported by various groups for free-space or fiber communications. Some of these can be incorporated into the present invention. In particular, the anodic oxidation scheme [18] or postgrowth tuning scheme [17] can easily provide the required device density and arbitrary wavelength variation within a small region. These also allow one to perform very flexible and accurate cavity-mode adjustment. The following discussion focuses on the utilization of anodic oxidation in the production of multiple-wavelength VCSEL PIE arrays.
To illustrate the wavelength adjustment of VCSELs using the anodic oxidation approach, the well-established 0.98 xcexcm VCSEL design with pseudomorphic InGaAs/GaAs quantum wells (QWs) and AlGaAs/GaAs DBRs will now be discussed. FIG. 1 provides an example of the aluminum and indium composition profiles for a multiple-wavelength bottom-emitting VCSEL [1]-[5]. The laser structure consists of a 32-period top p-mirror and a 19.5-period output n-mirror. The compositions for the AlGaAs quarter-wave layers are pure AlAs for the first 18 periods of the n-DBR and Al0.9Ga0.1As for the rest of the structure, except for the oxide-aperturing layer which is located in the first AlGaAs quarter-wave layer above the active region and has a 400 xc3x85 Al0.98Ga0.02As layer in the middle for selective lateral oxidation. The active region consists of three 80xc3x85 InGaAs QWs with 120xc3x85 GaAs barriers in between. To achieve multi-wavelength VCSEL PIE arrays by anodic oxidation requires two epitaxial growths. The first growth stops at the GaAs phase-tuning layer and then cavity modes for the individual channels are adjusted by performing anodic oxidation on this phase-tuning layer prior to the growth of the rest of the top DBR mirror. In FIG. 1, the phase-tuning layer is the fourth GaAs layer above the 1-xcex cavity, where xcex is the Bragg wavelength of the DBRs. The effects of choosing different tuning layer locations are covered in the following discussion.
FIG. 2A shows the corresponding calculated lasing wavelength, while FIG. 2B shows the corresponding threshold gain per quantum well as a function of the location and thickness of the GaAs phase-tuning layer. The number, m, shown beside each curve denotes that the tuning layer is the m-th GaAs layer above the 1-xcex cavity. For the special case: m=0, the tuning layer is the 1-xcex cavity itself. When m greater than 0 and if the GaAs tuning layer is 0.75-xcex (point A in the figure), it behaves just like a normal quarter-wave layer and the device will lase at the Bragg wavelength xcex. However, when the GaAs tuning layer is 0.5-xcex or 1.0-xcex (points B and C in the figure), this layer itself becomes a second cavity in the whole structure with the same cavity mode as the original 1-xcex cavity. As a result, there will be a splitting in energy levels xcex points B and C) due to the mode-coupling effect. The amount of splitting decreases as the cavity separation increases but the wavelength-tuning curve becomes more and more nonlinear. Theoretically, the tuning curve will gradually change from a straight line of slope 2xcex/ns2 to a straight line of zero slope when m increases from 0 to xcex. Here ns is the refractive index of the cavity. In order to achieve equidistant wavelength separation, a small m value, such as m=0 or at most m=1, should be used. Under this circumstance, the free-spectral range is wider so that the available wavelength span is also larger than the designs with a larger m. However, the overall variation in device threshold currents to achieve this maximum wavelength span will be much greater, as illustrated in FIG. 2B. Moreover, the tolerance in process control of the anodic oxidation also becomes tighter because of the steeper wavelength tuning rates. For current short-distance coarse WDM applications, it is possible to use the m=3 or even m=4 design because the channel spacing is still much wider than 4 nm, which is mainly limited by the receiver bandwidth.
In both FIG. 2A and FIG. 2B, the threshold characteristics of the adjacent higher-order and lower-order modes for the m=4 case (solid lines) are shown to illustrate the mode-coupling effect at the two ends of the free spectral range. This coupling effect caused not only nonlinearity but also an abrupt switch in device threshold and lasing wavelength. The observed systematic variation in threshold characteristics comes from the extending of optical field intensity from the central 1-xcex gain cavity into the GaAs phase-tuning layer when the cavity mode is detuned away from the Bragg wavelength of the DBRs. Another factor that also causes reduction in optical confinement factor is the shift of optical standing-wave peak away from the InGaAs QWs. Consequently, threshold current will have its lowest value at the Bragg wavelength and goes up in either direction of wavelength. In particular, when the tuning layer thickness is outside the (0.5xcex, 1.0xcex) range, the adjacent modes have lower threshold gains than the central mode and thus will dominate the lasing behavior.
The mode splitting at the 1.0-xcex tuning layer thickness determines the maximum available wavelength span. FIG. 3 shows the maximum lasing wavelength span and the required maximum threshold gain per well as a function of m. The solid curves are for the design shown in FIG. 1; while the dotted curves and the experimental data (O) are for the special case when we increase the first GaAs layer below the 1-xcex cavity to 1.25-xcex to avoid exposing AlGaAs layers on the etched surface. In reality, however, devices will not lase if the required threshold gain is higher than what the active material can provide, especially when the tuning layer thickness is close to 0.5xcex or 1.0xcex. If the maximum optical gain is experimentally limited to only 2400 cmxe2x88x921 from each In0.2Ga0.8As quantum well, the solid curve of the maximum wavelength span has to be reduced to the dash-dotted curve by excluding those wavelength ranges where the required threshold gain is beyond 2400 cmxe2x88x921 per quantum well. The curves suggest that m=2 would be the optimal design for providing the widest wavelength-tuning span whose wavelength-tuning characteristics are not overly steep. The latter is an important consideration for the processing control of anodic oxidation.
The above analysis and designs can be applied to other material systems at various wavelength regimes as well. The principle issue is the capability of performing successful epitaxial regrowth over the phase-tuning layer which can be GaAs, AlGaAs, InAlGaAs, InGaAsP, or others. For example, low-Al-content AlGaAs is very likely to be the tuning layer for 0.85-xcexcm WDM VCSEL PIE arrays so that high-quality AlGaAsxe2x80x94AlGaAs over-growth interface has to be achieved for the above mentioned regrowth method. However, we can also use dielectric DBR mirrors, transverse wet oxidation [17], or other techniques to vary the resonant wavelengths if the regrowth technology is not available.
In addition, modal noise is a well-known phenomenon for multimode fiber systems when a coherent light source is used. For a multimode WDM link, if single-mode VCSELs are used at the transmitter part, output intensity profile for each VCSEL channel at the other end of the fiber will be very likely centered in a few spots which are distributed over the 62.5 xcexcm-diameter core in an unpredictable manner. Moreover, these spots will move around the fiber core when the fiber is bent or vibrated somewhere. Therefore, broad bandwidth multimode VCSELs are recommended for multimode WDM systems [19] to produce a uniform intensity profile at the fiber output. In our designs, an oxide aperture extending only 1.0 xcexcm from the edges of VCSELs is created to reduce optical losses for the high-order modes to facilitate multiple lateral-mode operation.
(c) RCPDs in Optical Data Links
Narrow-band monolithically-integrated RCPD arrays are needed for real-time spectroscopic analysis or parallel demultiplexing of wavelength-encoded channels [9]-[12]. The key issue in design is to achieve high quantum-efficiency and narrow-band square-like photoresponse. Traditionally, there are two major approaches: one by RCPDs and the other by multiple-cavity dielectric filters combined with discrete photodetectors. Because of the large numerical aperture associated with multimode fibers, the RCPD approach is expected to be much better than the other to generate narrow-band photoresponse [1].
In view of the foregoing, a need exists for a direct coupled-multimode WDM data link with monolithically-integrated multiple-channel VCSEL and photodiodes arrays. The present invention satisfies that need, as well as others, and overcomes deficiencies in prior approaches.
The present invention is a direct-coupled optical data link structure for low-cost multimode wavelength-division multiplexing (WDM) in high-capacity (a few Gb/s up to 100 Gb/s) local-area network or fiber-to-the-desktop applications. This link comprises novel monolithically-integrated multiple-channel vertical-cavity surface-emitting laser (VCSEL) and narrow-band resonant-cavity photodetector (RCPD) arrays with their emitting or photon-collecting elements closely-packed within a small diameter circular area to facilitate self-aligned coupling to a single multimode fiber [1]-[12]. For multimode fibers, the devices are contained within a 60 xcexcm circle or alternately sized areas for matching to different fiber cores. For other fibers, this size may be varied to properly inject light from the VCSEL elements into the guided fiber modes. Unlike other techniques for making multiple wavelength laser or photodetector arrays, the present invention allows a multiple-channel VCSEL/RCPD link to be packaged in the same manner as a single-channel data link without resorting to complicated and expensive waveguide-coupling optics. Furthermore, one may then combine in parallel several of these direct-coupled WDM links to a fiber ribbon cable to thereby multiply the overall system capacity.
In order to achieve high-performance monolithically-integrated multiple-channel VCSEL and RCPD arrays at a low cost, the invention employs a circular device arrangement to obtain uniform and efficient fiber coupling. The individual VCSELs or RCPDs of the array can be designed with a conventional circular shape or a unique xe2x80x9cpiexe2x80x9d-like shape to maximize the light-emitting or photon-collecting area. Wavelength adjustment can be performed by several methods, including anodic oxidation and regrowth or postgrowth variable oxidation. The focus of these methods is to provide precisely-controlled anodic oxidation with a convenient binary-coding method. The advantage of this method over prior modified growth wavelength-adjustment techniques is that it can easily provide the required device density and arbitrary wavelength variation within a small photolithographically-defined region. For the VCSEL-transmitters, a unique and manufacturable planar-surface VCSEL structure is employed to facilitate device packaging. The idea is to define the VCSEL pillars, i.e. the closely-packed photonic-integrated emitter (PIE) array, by etching a narrow deep trench (about 3-5 xcexcm wide) around the VCSEL pillars and filling up the trench with an insulator, such as polyimide, which facilitates the addition of the metal cross-overs. On the RCPD-receiver side, the simplest broadcast-type configuration is adapted in this link, and wavelength-selective narrow-band RCPDs are achieved by minimizing cavity losses and increasing cavity length, i.e., to maximize the cavity Q-factor. A novel double quantum-well absorber design has been used to ensure a uniform photoresponse over the whole wavelength range covered by the RCPD array. In addition, a novel coupled-cavity structure is proposed to achieve passbands with flat tops and steep sides to ensure proper channel alignment.
An object of the invention is to provide a method whereby low cost wavelength division multiplexed (WDM) optical link may be produced.
Another object of the invention is to provide for inexpensively packaging the multiple channels of a WDM optical link without the need of waveguide-coupling optics.
Another object of the invention is to provide a method of creating planar surface VCSELs which are easy to manufacture.
Another object of the invention is to provide general guidelines for WDM VCSEL array design, whether planar or not.
Further objects and advantages of the invention will be brought out in the following portions of the specification, wherein the detailed description is for the purpose of fully disclosing preferred embodiments of the invention without placing limitations thereon.

Direct-coupled multimode WDM optical data links with monolithically-integrated multiple-channel VCSEL and photodetector arrays

The Regents of the University of California


Thermoplastic resin compositions containing a rubber-reinforced thermoplastic resin (A) obtained by graft polymerizing a monomeric mixture (b) in the presence of a rubber-like polymer (a), and a copolymer (B) obtained by polymerizing an aromatic vinyl compound, a vinyl cyanide compound and optionally other copolymerizable monomeric compound(s), which copolymer (B) being a mixture of a copolymer (B1) having Mw of 50,000 to 110,000 and a copolymer (B2) having Mw of 115,000 to 400,000. The content of the rubber-like polymer (a) content in the rubber-reinforced thermoplastic resin (A) is 10 to 25% by weight, the vinyl cyanide monomeric unit in the acetone soluble matter is 15 to 40% by weight, and the ratios of Mw to Mn and MZ to Mn of the acetone soluble matter being 2 to 5 and 5 to 11, respectively.

The present invention relates to a thermoplastic resin composition, more particularly relates to a thermoplastic resin of which the molded articles show good plate adhesion to their surfaces, and also have excellent coating properties and improved impact resistance.
The molded articles of rubber-reinforced thermoplastic resins such as ABS resins are often subjected to secondary works such as plating, coating, sputtering, ion plating, etc. Particularly, in the case of plating, if a molded article is simply plated, there may not be obtained sufficient adhesive strength between the deposit and the surface of the molded article, so that the deposit releases easily from the surface in use. For enhancing adhesive strength of the deposit, a method is known in which the surface of the molded article to be plated is subject to an oxidation treatment to decompose rubber material present in the molded article surface layer and then the article surface is etched to form fine indents, after which plating is conducted. According to this method, it is supposed possible to enhance adhesive strength of the deposit by anchor effect because the deposit bites into the indents. Practically, however, such fine indents formed by etching are deformed during plating, and the desired adhesive strength can not be obtained.
Further, there is a problem that by the etching the mechanical strength, particularly impact resistance of the molded articles is deteriorated. Thus, there is a demand to provide a resin composition having a good balance of plate adhesion and mechanical properties when processed into a molded article.
Further, in coating of the articles molded from conventional rubber-reinforced thermoplastic resins such as ABS resins, there is a problem of improper adhesion of the coating film, color shading of the coated surface due to suction of the thinner into the molded article and consequent impairment of its visual appearance.
As a result of the present inventors' earnest study to solve the above problem, it has been found that the articles molded from a rubber-reinforced thermoplastic resin composition having a specific ratio of weight-average molecular weight Mw to number-average molecular weight Mn of the acetone soluble matter (Mw/Mn ratio) and a specific ratio of Z-average molecular weight MZ to number-average molecular weight Mn of the acetone soluble matter (MZ/Mn ratio) show good plate adhesion on their surface and also have excellent coating properties and mechanical strength, typically impact resistance. The present invention has been attained on the basis of the above findings.

Thermoplastic resin composition and its molded articles


A concept for reducing the number of parts in, and for simplifying the assembly of, a plate and fin type heat exchanger in which a fluid makes plural passes at least at one level of the heat exchanger. A single layer of a secondary heat transfer material replaces multiple detail parts of the prior art and is appropriately configured in conjunction with flow divider members to assure continuous fluid flow to and between fluid passes.

In plate and fin heat exchangers, a "fin" layer of a relatively ductile sheet or strip material, crimped to a corrugated configuration, is placed between overlying and underlying plates where it acts as a secondary heat transfer surface. In some instances, particularly in the case of compact, high performance heat exchangers, it is possible or desirable, or both, to conduct at least one of the fluids admitted to the heat exchanger in a serpentine or reversing flow path between adjacent plates. This poses a problem in respect of the "fin" layer since flow in a serpentine path has components of transverse movement which cannot obviously be accommodated by the as-formed corrugated "fin" material. In the known prior art, this problem has been dealt with by using a "fin" layer comprised of multiple "fin" segments including a connecting segment in which the corrugations orient at right angles to the corrugations of connected segments. The segments are configured to achieve miter joints at turn-around locations. This practice satisfactorily solves the problem of impeded flow but is a relatively costly solution. Multiple "fin" segments of different configuration must be provided, and separately and selectively laid in place in assembling each level of a plate and fin heat exchanger. The advantages of a multi-pass heat exchanger accordingly have heretofore been possible only by an expenditure of relatively high materials and labor costs.


An absorbing agent has a diffusing absorbency under pressure of not less than 25 g/g when 60 minutes elapsed after absorption is started, and a water-soluble content is above 0 percent by weight and not more than 7 percent by weight. The absorbing agent is prepared by surface-crosslinking a precursor of the absorbing agent obtained by performing an aqueous solution polymerization of a hydrophilic unsaturated monomer having not less than 50 mole percent neutralized acrylic acid as a main component using a specific crosslinking agent having a main component composed of an ester compound of a specific polyhydroxy alcohol and an unsatuated carboxylic acid, and a high-boiling component having at least two alcohol structures in a molecule as a specific ratio. As a result, an absorbing agent having excellent properties such as the diffusing absorbency under pressure is high, the water soluble content is small, and the amount of wet back of the aqueous liquid after a long period of time is small, water absorbency under pressure can be stably maintained for a long period of time can be achieved.

Recently, an absorbent resin is widely used in sanitary goods such as paper diaper, sanitary napkin, incontinence pad, etc., for the purpose of absorbing liquid.
Examples of known absorbent resins include: a partially neutralized crosslinked polymer of polyacrylic acid (Japanese Laid-Open Patent Publication No. 84304/1980 (Tokukaisho 55-84304), Japanese Laid-Open Patent Publication No. 108407/1980 (Tokukaisho 55-108407) and Japanese Laid-Open Patent Publication No. 133413/1980 (Tokukaisho 55-133413)); a hydrolyzed graft polymer of starch-acrylonitrile (Japanese Examined Patent Publication No. 43995/1974 (Tokukosho 46-43995)); a neutralized graft polymer of starch-acrylic acid (Japanese Laid-Open Patent Publication No. 125468/1976 (Tokukaisho 51-125468)); a saponified copolymer of vinyl acetate-acrylic ester (Japanese Laid-Open Patent Publication No. 14689/1977 (Tokukaisho 52-14689)); a hydrolyzed copolymer of acrylonitrile or of acrylamide (Japanese Examined Patent Publication No. 15959/1978 (Tokukosho 53-15959)); a crosslinked polymer of cationic monomer (Japanese Laid-Open Patent Publication No. 154709/1983 (Tokukaisho 58-154709) and Japanese Laid-Open Patent Publication No. 154710/1983 (Tokukaisho 58-154710)).
Notable properties of the absorbent resin include absorbing capacity and absorbency under pressure when it is in contact with an aqueous liquid like a body fluid, gel strength, and absorbing power of absorbing liquid from a base material containing an aqueous liquid, etc. Conventionally, the absorbent resins having some of the above-mentioned properties which show desirable properties (absorption properties) in their applications of paper diaper, sanitary napkin, etc., as well as absorbent materials and the absorbent product using such absorbent resins have been proposed.
Examples of such absorbent resins, absorbent materials and absorbent products include: an absorbent resin disclosing a combination of a specific gel capacity, shear modulus and an extraction polymer content (U.S. Pat. No. 4,654,039); an absorbent resin having predeterined ranges of absorbing capacity and absorbency under pressure and gel stability, and a paper diaper and a sanitary napkin using such absorbent resin (Japanese Laid-Open Patent Publication No. 185550/1985 (Tokukaisho 60-185550)), (Japanese Laid-Open Patent Publication No. 185551/1985 (Tokukaisho 60-185551)) and (Japanese Laid-Open Patent Publication No. 185804/1985 (Tokukaisho 60-185804)); a paper diaper using an absorbent resin having predetermined ranges of absorbing capacity, absorbency under pressure and a gel stability (Japanese Laid-Open Patent Publication No. 185805/1985 (Tokukaisho 60-185805)); an absorbent product having predetermined absorbing capacity, absorbing power and water soluble content (Japanese Laid-Open Patent Publication No. 21902/1988 (Tokukaisho 63-21902)); an absorbent sanitary product including an absorbent resin having predetermined ranges of absorbing capacity, absorbing capacity under pressure, and a gel breaking strength (Japanese Laid-Open Patent Publication No. 99861/1988 (Tokukaisho 63-99861)); a paper diaper including an absorbent resin having predetermined ranges of absorbing capacity and absorbency under pressure (Japanese Laid-Open Patent Publication No. 34167/1990 (Tokukaihei 2-34167)); an absorbing agent containing an absorbent resin having predetermined ranges of absorbing capacity under pressure and particle diameter (European Patent No. 339,461); an absorbing agent including at least a predetermined amount of an absorbent resin having predetermined ranges of absorbency under pressure and absorbing capacity under pressure in a short period of time (European Patent No. 443,627); an absorbing synthethic material having at least predetermined amount of absorbent resin having predetermined ranges of deformation and absorbing index when applying a load (European Patent No. 532,002).
Recently, still thinner sanitary goods such as a paper diaper and a sanitary napkin of higher quality have been demanded, and an amount of use of the absorbent resin or weight percent of the absorbent resin in the absorbent material mainly composed of absorbent resin and hydrophilic fiber (hereinafter simply referred to as a resin concentration) has been increasing. Namely, by reducing the amount of hydrophilic fiber having a small bulk specific gravity and increasing the amount of the absorbent resin having a large bulk specific gravity, the ratio of the absorbent resin in the absorbent material is raised, and a thinner sanitary material can be achieved without reducing the absorbing capacity.
However, earnest researches have been made by the inventors of the present invention in order to increase the absorbing amount of the sanitary material, for example, by increasing the resin concentration in the absorbent material. As a result, the inventors have found that the absorbent material having a higher resin concentration than conventional absorbent material cannot be used without having problems such as leakage of aqueous liquid from the sanitary goods, etc., only by controlling the described absorbing capacity, absorbency under pressure, gel strength, absorbing capacity, etc. For example, as to the absorbent resin which has been viewed with interest in which only absorbing capacity under pressure is large, by raising the resin concentration, the liquid dispersibility of the absorbent material is significantly reduced.
Further researches have been made by the inventors on absorbing properties of the absorbent material having higher resin concentration than conventional absorbent material. As a result, they have found that in the case of using a mixture of a known absorbent resin, a hydrophilic fiber is used as an absorbent material, although when a resin concentration is low, the absorbent material shows a predetermined level of absorbing properties, when a resin concentration is above 40 percent by weight, such unpreferable conditions that the liquid dispersibility is rapidly lowered, the absorbing capacity of weight per unit of the absorbent material is lowered, the water absorbing capacity cannot be ensured for a long period of time; an amount of wet back of the aqueous liquid increases, etc., would occur. Namely, when a mixture of the known absorbent resin and the hydrophilic fiber is used as an absorbent material, the above-mentioned problems would arise.
Accordingly, an object of the present invention is to eliminate the above-mentioned problems and to provide an absorbing agent having excellent properties (absorbing properties) such as very high liquid diffusivity and a stability over time of the absorbing capacity irrespectively of the resin concentration or the structure of the absorbent material, for example, when it is used as sanitary goods, etc., as well as a process of manufacturing such absorbing agent and the absorbent product including the absorbing agent.
Another object of the present invention is to provide an absorbing agent having excellent properties (absorbing properties, etc.,) of maintaining very high liquid diffusivity and absorbing capacity even with high resin concentration.

Process for manufacturing an absorbing agent and absorbent material


An elevator system including a hoistway, an elevator car disposed in the hoistway, the elevator car including a first braking device configured to engage a first braking surface in a first direction in the event of a guidance occurrence, and a second braking device configured to engage a second braking surface in a second direction in the event of the guidance occurrence.

Elevator systems are widely used in a variety of applications for transporting passengers from one point to another. In rare situations, such as during earthquakes, the elevator car in an elevator system may become disengaged with the rails. Typical contemporary elevator systems often include redundant braking (e.g. machine brake and safeties) for such situations. As such, increased requirements for elevators systems include rail to building interface and elevator car holding/braking systems. These additional requirements increase the overall cost of the system by adding mass to the elevator car, and potentially changing motor requirements.
Therefore, an improved braking system for an elevator system is desired.


Novel compounds of formula I, with the exception of

The present invention is related to novel compounds having affinity to one or more GABAB receptors, as well as to their pharmaceutically acceptable salts, solvates and stereoisomers. The invention is also related to processes for their preparation, pharmaceutical compositions containing said therapeutically active compounds and to the use of said active compounds in therapy.
Gastro-oesophageal reflux disease (GORD) is the most prevalent upper gastrointestinal tract disease. Current therapy has aimed at reducing gastric acid secretion, or at reducing oesophageal acid exposure by enhancing oesophageal clearance, lower oesophageal sphincter tone and gastric emptying. The major mechanism behind reflux has earlier been considered to depend on a hypotonic lower oesophageal sphincter. However recent research (e.g. Holloway and Dent (1990) Gastroenterol. Clin. N. Amer. 19, 517-535) has shown that most reflux episodes occur during transient lower oesophageal sphincter relaxations, hereinafter referred to as TLOSR, i.e. relaxations not triggered by swallows. It has also been shown that gastric acid secretion usually is normal in patients with GORD.
Consequently, there is a need for compounds which reduce the incidence of TLOSR and thereby prevent reflux.
Pharmaceutical compositions comprising a local anaesthetic, adapted to inhibit relaxation of the lower oesophageal sphicter are disclosed in WO 87/04077 and in U.S. Pat. No. 5,036,057. Recently GABAB-receptor agonists have been shown to inhibit TLOSR which is disclosed in WO 98/11885.
GABA (4-aminobutanoic acid) is an endogenous neurotransmitter in the central and peripheral nervous systems. Receptors for GABA have traditionally been divided into GABAA and GABAB receptor subtypes. GABAB receptors belong to the superfamily of G-protein coupled receptors. GABAB receptor agonists are being described as being of use in the treatment of CNS disorders, such as muscle relaxation in spinal spasticity, cardiovascular disorders, asthma, gut motility disorders such as irritable bowel syndrome (IBS) and as prokinetic and anti-tussive agents. GABAB receptor agonists have also been disclosed as useful in the treatment of emesis (WO 96/11680) and recently, as mentioned above, in the inhibition of TLOSR (WO 98/11885).
The most studied GABAB receptor agonist is baclofen (4-amino-3-(chlorophenyl)butanoic is acid) disclosed in the Swiss patent No. CH 449, 046. Baclofen has for several years been used as an antispastic agent. EP 0356128 describes the use of the specific compound (3-aminopropyl)methylphosphinic acid, as a potent GABAB receptor agonist, in therapy. EP 0181833 discloses substituted 3-aminopropylphosphinic acids which are found to have very high affinities towards GABAB receptor sites. In analogy to baclofen, the compounds can be used as for instance muscle relaxants. EP 0399949 discloses derivatives of (3-aminopropyl)methylphosphinic acid which are described as potent GABAB receptor agonists. These compounds are stated to be useful as muscle relaxants. EP 0463969 and FR 2722192 are both applications related to 4-aminobutanoic acid derivatives having different heterocyclic substituents at the 3-carbon of the butyl chain. Structure-activity relationships of several phosphinic acid analogues with respect to their affinities to the GABAB receptor as well as their muscle relaxant effect are discussed in J. Med. Chem. (1995), 38, 3297-3312. The conclusion in said article is that considerably stronger muscle relaxation could be achieved with the (S)-enantiomer of 3-amino-2-hydroxypropylmethylphosphinic acid than with baclofen and without the occurrence of unwanted CNS effects.
In literature the phosphinic acids having a hydrogen atom attached to phosphorous also are named phosphonous acids. These are two names for the same compounds and both names can be used. However, we have chosen to use the name phosphinic acids for the compounds according to the present invention.
The present invention provides novel compounds of the formula I
wherein
R1 represents hydrogen, hydroxy, lower alkyl, lower alkoxy or halogen;
R2 represents hydroxy, mercapto, halogen, or an oxo group;
R3 represents hydrogen or lower alkyl (optionally substituted with hydroxy, mercapto, lower alkoxy, lower thioalkoxy or aryl);
R4 represents hydrogen, lower alkyl (optionally substituted with aryl), or aryl;
and pharmaceutically acceptable salts, solvates and the stereoisomers thereof,
with the exceptions of:
i) the racemate of (3-amino-2-hydroxypropyl)phosphinic acid, and
ii) (2R/S, 3R)-(3-amino-2-hydroxybutyl)phosphinic acid.
In a preferred embodiment
R1 represents hydrogen, a lower alkyl or halogen;
R2 represents halogen, hydroxy or an oxo group;
R3 represents hydrogen; and
R4 represents hydrogen;
with the exception of the racemate of (3-amino-2-hydroxypropyl)phosphinic acid.
Even more preferred compounds are (3-amino-2-fluoropropyl)phosphinic acid, (2R)-(3-amino-2-fluoropropyl)phosphinic acid, (2S)-(3-amino-2-fluoropropyl)phosphinic acid, (3-amino-2-fluoro-1-methylpropyl)phosphinic acid, (3-amino-2-oxopropyl)phosphinic acid, (2S)-(3-amino-2-hydroxypropyl)phosphinic acid, (2R)-(3-amino-2-hydroxypropyl)phosphinic acid and (3-amino-1-fluoro-2-hydroxypropyl)phosphinic acid.
Within the scope of the invention, it is to be understood that when R2 is an oxo group the bond between R2 and the carbon is a double bond.
Within the scope of the invention, it is to be understood by xe2x80x9clowerxe2x80x9d radicals and compounds, for example, those having up to and including 7, especially up to and including 4, carbon atoms. Also the general terms have the following meanings:
Lower alkyl is, for example, C1-C4 alkyl, such as methyl, ethyl, n-propyl or n-butyl, also isopropyl, isobutyl, secondary butyl or tertiary butyl, but may also be a C5-C7 alkyl group such as a pentyl, hexyl or heptyl group.
Lower alkoxy is, for example, C1-C4 alkoxy, such as methoxy, ethoxy, n-propoxy or n-butoxy, also isopropoxy, isobutoxy, secondary butoxy or tertiary butoxy, but may also be a C5-C7 alkoxy group, such as a pentoxy, hexoxy or heptoxy group.
Lower thioalkoxy is, for example, C1-C4 thioalkoxy, such as thiomethoxy, thioethoxy, n-thiopropoxy or n-thiobutoxy, also thioisopropoxy, thioisobutoxy, secondary thiobutoxy or tertiary thiobutoxy, but may also be a C5-C7 thioalkoxy group, such as a thiopentoxy, thiohexoxy or thioheptoxy group.
Halogen is halogen of atomic number up to and including 35, such as fluorine or chlorine and less preferred bromine.
The compounds according to formula I of the invention are of amphoteric nature and may be presented in the form of internal salts. They can also form acid addition salts and salts with bases. Such salts are particularly pharmaceutically acceptable acid addition salts, as well as pharmaceutically acceptable salts formed with bases. Suitable acids for the formation of such salts include, for example, mineral acids such as hydrochloric, hydrobromic, sulfuric, or phosphoric acid or organic acids such as sulfonic acids and carboxylic acids. Salts with bases are, for example, alkali metal salts, e.g. sodium or potassium salts, or alkaline earth metal salts, e.g. calcium or magnesium salts, as well as ammonium salts, such as those with ammonia or organic amines. The salts may be prepared by conventional methods.
When one or more stereocentre is present in the molecule, the compounds according to formula I can be in the form of a stereoisomeric mixture, i.e. a mixture of diastereomers and/or racemates, or in the form of the single stereoisomers, i.e. the single enantiomer and/or diastereomer. The compounds can also be in the form of solvates, e.g. hydrates.
All of the compounds according to the formula I can be used for the inhibition of TLOSR, and thus for the treatment of gastro-oesophageal reflux disease. The said inhibition of TLOSR also implies that the said compounds of formula I can be used for the treatment of regurgitation in infants. Effective management of regurgitation in infants would be an important way of managing failure to thrive due to excessive loss of ingested nutrient. Furthermore the novel compounds can be used for the treatment of GORD-related or non-GORD related asthma, belching, coughing, pain, cocaine addiction, hiccups, IBS, dyspepsia, emesis and nociception.
As opposed to what is stated in prior art, (J. Med. Chem. (1995) 3297-3312 and The GABA Receptors; Second Edition, Edited by S. J Enna and Norman Bowery, Humana Press (1997) especially p. 281-282), the compounds according to the invention have surprisingly high metabolic stability in spite of the presence of a Pxe2x80x94H bond. The compounds also possess a surprisingly high therapeutic index.
The compounds according to formula I of the present invention may be prepared by one of the following methods.
A) A Compound of Formula II
in which R1 and R3 are as defined above in formula I, X is hydrogen or a protecting group such as xe2x80x94CCH3(OCH2CH3)2, Z is a protecting group such as t-butyloxycarbonyl and Y is hydrogen or a protecting group such as lower alkyl, which compound of formula II may have been synthesized by a condensation reaction according to Scheme 1 employing an appropriate N-protected amino acid ester in which R3 is as defined above, W is a protecting group such as lower alkyl and Z is as defined in formula II, and a suitable protected phosphinic acid derivative in which R1 is as defined above in formula I, X and Y are as defined in formula II, and a base such as lithium diisopropylamide,
is
a) optionally converted by an N-alkylation reaction in order to introduce R4 if R4 is desired to be not equal to hydrogen, and thereafter a hydrolytic reaction to obtain a compound of formula III
xe2x80x83wherein R1, R3 and R4 are as defined above in formula I, and optionally convert the above resulting compound III into another chemical compound of the formula III and/or sepatate a resulting mixture of isomers into the individual isomers and/or convert a resulting salt into the free compound of the formula III and/or into another salt and/or convert a resulting free compound of the formula III into a salt to correspond to the above definition, or
b) converted by a reductive reaction, optionally an N-alkylation reaction if R4 is desired to be not equal to hydrogen, and finally a hydrolytic reaction to obtain a compound of formula IV
xe2x80x83wherein R1, R3 and R4 are as defined above in formula I, and optionally convert the above resulting compound IV into another chemical compound of the formula IV and/or sepatate a resulting mixture of isomers into the individual isomers and/or convert a resulting salt into the free compound of the formula IV and/or into another salt and/or convert a resulting free compound of the formula IV into a salt to correspond to the above definition, or
c) converted by a reductive reaction followed by a deoxohalogenation reaction, optionally an N-alkylation reaction in order to introduce R4 if R4 is desired to be not equal to hydrogen, and finally a hydrolytic reaction to obtain a compound of formula V
xe2x80x83wherein R1, R3 and R4 are as defined above in formula I and Halo is a halogen atom, and optionally convert the above resulting compound V into another chemical compound of the formula V and/or sepatate a resulting mixture of isomers into the individual isomers and/or convert a resulting salt into the free compound of the formula V and/or into another salt and/or convert a resulting free compound of the formula V into a salt to correspond to the above definition; or
B) A Compound of Formula VI
in which R1, and R3 are as defined above in formula I, X is hydrogen or a protecting group such as xe2x80x94CCH3(OCH2CH3)2, T is a group that can be converted to axe2x80x94NH2 group, and Y is hydrogen or a protecting group such as lower alkyl, which compound of formula VI may have been synthesized by a condensation reaction according to Scheme 2 employing an 2,3-epoxypropyl derivative, such as an appropriate N-protected 2,3-epoxypropylamine derivative or an epichlorohydrin derivative, in which R1 and R3 is as defined above in formula I, and a suitable protected phosphinic acid derivative activated by O-silylation, in which X and Y are as defined in formula VI, and a Lewis acid such as anhydrous ZnCl2,
is
a) converted by a reaction where the trimethylsilyl group is replaced by a hydrogen atom, a reaction where the T group as defined in formula VI is converted to xe2x80x94NHR4 wherein R4 is as defined above in formula I, and finally a hydrolytic reaction to obtain a compound of formula IV
xe2x80x83wherein R1, R3 and R4 are as defined above in formula I, and optionally convert the above resulting compound IV into another chemical compound of the formula IV and/or sepatate a resulting mixture of isomers into the individual isomers and/or convert a resulting salt into the free compound of the formula IV and/or into another salt and/or convert a resulting free compound of the formula IV into a salt to correspond to the above definition, or
b) converted by a reaction where the trimethylsilyl group is replaced by hydrogen, an oxidative reaction, a reaction where the T group as defined in formula VI is converted to xe2x80x94NHR4 wherein R4 is as defined above in formula I, and finally a hydrolytic reaction to obtain a compound of formula III
xe2x80x83wherein R1, R3 and R4 are as defined above in formula I, and optionally convert the above resulting compound III into another chemical compound of the formula III and/or sepatate a resulting mixture of isomers into the individual isomers and/or convert a resulting salt into the free compound of the formula III and/or into another salt and/or convert a resulting free compound of the formula III into a salt to correspond to the above definition, or
c) converted by a reaction where the trimethylsilyl group is replaced by hydrogen, a deoxohalogenation reaction, a reaction where the T group as defined in formula VI is converted to xe2x80x94NHR4 wherein R4 is as defined above in formula I, and finally a hydrolytic reaction to obtain a compound of formula V
xe2x80x83wherein R1, R3 and R4 are as defined above in formula I, and Halo is a halogen atom, and optionally convert the above resulting compound V into another chemical compound of the formula V and/or sepatate a resulting mixture of isomers into the individual isomers and/or convert a resulting salt into the free compound of the formula V and/or into another salt and/or convert a resulting free compound of the formula V into a salt to correspond to the above definition; or
C) A Compound of Formula VII
in which R1 is as defined above in formula I, X is hydrogen or a protecting group such as xe2x80x94CCH3 (OCH2CH3)2, U is an electron-withdrawing group, such as for instance xe2x80x94CN or xe2x80x94CO2Et which can be converted to a xe2x80x94CH2NH2 group, and Y is hydrogen or a protecting group such as lower alkyl, and Halo is a halogen atom, which compound of formula VII may have been synthesized by an addition reaction according to Scheme 3 employing an unsaturated compound in which R1 is as defined above in formula I, U and halo are as defined in formula VII, and a suitable protected phosphinic acid derivative activated by O-silylation, in which X and Y are as defined in formula VII,
is converted by a reaction where the U group is being converted to xe2x80x94NHR4 wherein R4 is a defined above in formula I, and a hydrolytic reaction to obtain a compound of formula VIII
wherein R1 and R4 are as defined above in formula I and Halo is a halogen atom, and optionally convert the above resulting compound viii into another chemical compound of the formula VIII and/or separate a resulting mixture of isomers into the individual isomers and/or convert a resulting salt into the free compound of the formula VIII and/or into another salt and/or convert a resulting free compound of the formula VIII into a salt to correspond to the above definition; or
D) A Compound of Formula IX Optionally as an Individual Stereo Isomer
in which R1, R3 and R4 are as defined in formula I, Z is a protecting group such as t-butyloxycarbonyl and Halo is a halogen atom, which compound of formula IX may have been synthesized by a substitution reaction according to Scheme 4 employing an electrophilic compound in which R1, R3 and R4 are as defined above, L is a leaving group such as iodo, Z and Halo are as defined above, and phosphinic acid activated by O-silylation,
is converted by a hydrolytic reaction to a compound of formula V
wherein R1, R3 and R4 are as defined above in formula I, and optionally convert the above resulting compound V into another chemical compound of the formula V and/or sepatate a resulting mixture of isomers into the individual isomers and/or convert a resulting salt into the free compound of the formula V and/or into another salt and/or convert a resulting free compound of the formula V into a salt to correspond to the above definition; or
E) A Compound of Formula XI
in which R1, R3 and R4 are as defined above in formula I, X is hydrogen or a protecting group such as xe2x80x94CCH3(OCH2CH3)2, and Y is hydrogen or a protecting group such as lower alkyl, which compound of formula XI may have been synthesized by an addition reaction according to Scheme 4 treating an unsaturated phosphinic acid derivative, in which R1, R3 and R4 are as defined in above in formula I, with H2S, a mercaptide ion (HSxe2x88x92) or a protected mercapto compound such as benzyl thiol in which case the protective group thereafter is removed
is converted by a hydrolytic reaction to obtain a compound of formula XII,
in which R1, R3 and R4 are as defined above in formula I, and optionally convert the above resulting compound XII into another chemical compound of the formula XII and/or sepatate a resulting mixture of isomers into the individual isomers and/or convert a resulting salt into the free compound of the formula XII and/or into another salt and/or convert a resulting free compound of the formula XII into a salt to correspond to the above definition.
The invention is described more in detail by the following non-limiting examples

Abstract: i) the racemate of (3-amino-2-hydroxypropyl)phosphinic acid; and

Abstract: ii) (2R/S, 3R)-(3-amino-2-hydroxybutyl)phosphinic acid,

Abstract: having affinity to one or more GABAB receptors, their pharmaceutically acceptable salts, solvates and stereoisomers, as well as processes for their preparation, pharmaceutical compositions containing said therapeutically active compounds and the use of said active compounds in therapy


A circuit interrupting device is disclosed that includes a first conductor, a second conductor, a switch between the first conductor and the second conductor wherein the switch is disposed to selectively connect and disconnect the first conductor and the second conductor, a circuit interrupter disposed to generate a circuit interrupting actuation signal, a solenoid coil and plunger assembly disposed to open the switch wherein the solenoid coil and plunger assembly is actuatable by the circuit interrupting actuation signal wherein movement of the plunger causes the switch to open, and a test assembly that is configured to enable a test of the circuit interrupter initiating at least a partial movement of the plunger in a test direction, from a pre-test configuration to a post-test configuration, without opening the switch.

1. Field
The present disclosure relates to circuit interrupting devices. In particular, the present disclosure is directed to re-settable circuit interrupting devices and systems that comprises ground fault circuit interrupting devices (GFCI devices), arc fault circuit interrupting devices (AFCI devices), immersion detection circuit interrupting devices (IDCI devices), appliance leakage circuit interrupting devices (ALCI devices), equipment leakage circuit interrupting devices (ELCI devices), circuit breakers, contactors, latching relays and solenoid mechanisms. More particularly, the present disclosure is directed to circuit interrupting devices that include a circuit interrupter that can break electrically conductive paths between a line side and a load side of the devices.
2. Description of the Related Art
Many electrical wiring devices have a line side, which is connectable to an electrical power supply, and a load side, which is connectable to one or more loads and at least one conductive path between the line and load sides. Electrical connections to wires supplying electrical power or wires conducting electricity to the one or more loads are at line side and load side connections. The electrical wiring device industry has witnessed an increasing call for circuit breaking devices or systems which are designed to interrupt power to various loads, such as household appliances, consumer electrical products and branch circuits. In particular, electrical codes require electrical circuits in home bathrooms and kitchens to be equipped with circuit interrupting devices, such as ground fault circuit interrupting devices (GFCI), for example.
In particular, GFCI devices protect electrical circuits from ground faults which may pose shock hazards. To prevent continued operation of the particular electrical device under such conditions, a GFCI device monitors the difference in current flowing into and out of the electrical device. Load-side terminals provides electricity to the electrical device.
A differential transformer measures the difference in the amount of current flow through the wires (i.e.—hot and neutral) disposed on the primary side (or core in the case of a toroid differential transformer) via a current signal analyzer, when the difference in current exceeds a predetermined level, e.g., 5 milliamps, indicating that a ground fault may be occurring, the GFCI device interrupts or terminates the current flow within a particular time period, e.g., 25 milliseconds or greater. The current may be interrupted via a solenoid coil that mechanically opens switch contacts to shut down the flow of electricity. A GFCI device includes a reset button that allows a user to reset or close the switch contacts to resume current flow to the electrical device. A GFCI device may also include a user-activated test button that allows the user to activate or trip the solenoid to open the switch contacts to verify proper operation of the GFCI device.
Presently available GFCI devices, such as the device described in U.S. Pat. No. 4,595,894 (the '894 patent) which is incorporated herein in its entirety by reference, use an electrically activated trip mechanism to mechanically break an electrical connection between the line side and the load side. Such devices are resettable after they are tripped by, for example, the detection of a ground fault. In the device discussed in the '894 patent, the trip mechanism used to cause the mechanical breaking of the circuit (i.e., the conductive path between the line and load sides) includes a solenoid (or trip coil). A test button is used to test the trip mechanism and circuitry used to sense faults, and a reset button is used to reset the electrical connection between line and load sides.
In addition, intelligent ground fault circuit interrupting (IGFCI) devices are known in the art that can automatically test internal circuitry on a periodic basis. Such GFCI devices can perform self-testing on a monthly, weekly, daily or even hourly basis. In particular, all key components can be tested except for the relay contacts. This is because tripping the contacts for testing has the undesirable result of removing power to the user's circuit. However, once a month, for example, such GFCI devices can generate a visual and/or audible signal or alarm reminding the user to manually test the GFCI device. The user, in response to the signal, initiates a test by pushing a test button, thereby testing the operation of the contacts in addition to the rest of the GFCI circuitry. Following a successful test, the user can reset the GFCI device by pushing a reset button.
Examples of such intelligent ground fault circuit interrupter devices can be found in U.S. Pat. Nos. 5,600,524, 5,715,125, and 6,111,733 each by Nieger et al. and each entitled "INTELLIGENT GROUND FAULT CIRCUIT INTERRUPTER," and each of which is incorporated herein by reference in its entirety. Additionally, another example of an intelligent ground fault current interrupter device can be found in U.S. Pat. No. 6,052,265 by Zaretsky et al., entitled "INTELLIGENT GROUND FAULT CIRCUIT INTERRUPTER EMPLOYING MISWIRING DETECTION AND USER TESTING," which is incorporated herein by reference in its entirety.

Detecting and sensing actuation in a circuit interrupting device


A cylindrical three dimensional picture capable of being viewed through an angle of 360.degree. includes a cylinder surrounded by a photograph, in turn surrounded by a lenticular lens or parallax barrier strip. The photograph is made from a photo emulsion that is exposed and subsequently developed for viewing. The photo emulsion is exposed to the subject, or images of the subject, through the lenticular lens or parallax barrier strip.

Since the birth of photography, photographers and viewers have strived to make pictures more realistic by creating three dimensional images. This has lead to the development of a wide range of methods and equipment for recording and viewing three dimensional images. Such methods included the viewing of the images through special lenses, such as 3D glasses for the individual viewer; the creation of images on a flat surface through use of concentric circular lenses in conjunction with line screens having alternate opaque and transparent vertical lines; creating three dimensional images through use of a plurality of angularly spaced mirrors; viewing images through rapidly moving screens having spaced-apart openings; viewing a television screen through a series of vertically extending cylindrical lenses mounted to the television screen between the viewer and the television screen; and rapidly rotating a screen displaying a fast changing series of images generated by an external projector rotating synchronously with the screen.
Although prior art 3D images appeared to have depth, none of the prior methods of creating and viewing 3D figures have resulted in the creation of a three dimensional fixed image that can be viewed through an angle of 360.degree..

Method and apparatus for creating cylindrical three dimensional picture


The supply of available tasks that may be executed by a blocked processor while it is waiting for the end of a conflict with another processor, is controlled by temporarily lowering the interrupt priority to a minimum level above which it will be permitted to accept other tasks for execution.

This invention relates to controlling the supply of available tasks that may be executed by a processor when its work has been temporarily blocked by a conflict with another processor.
Such blocking may happen, for example, when one processor attempts to enter a critical region of code where the other processor is working. (Critical regions are set up to protect data stored in a shared memory against conflicting accesses by two or more processors.) Typically the critical region is protected by a flag in shared memory that is set when a processor is working in the region, and otherwise is cleared. A processor always checks the flag before entering the region, and if it finds the flag set, waits until the other processor has left the region.
In some systems, the waiting processor is assigned to work on other tasks until the critical region becomes free. Switching to such other tasks wastes time because current context information must be stored and recovered again each time another task is done.
Another known approach takes advantage of the fact that in some computers (e.g., Digital Equipment Corporation's VAX) each task is assigned one of, e.g., 32 interrupt priority levels that are ranked according to their relative urgencies and the relative overhead costs of executing them. Generally, when a processor is blocked from working in a critical region having a given interrupt priority level, the blocked processor may service only other tasks having higher interrupt priority levels.


A slide switch comprises a plurality of sets of aligned terminals, each set comprising at least a center terminal and two end terminals, one to either side of the center terminal and aligned along a common axis therewith, and a plurality of elongate slides respectively associated with the sets of terminals. The slides are of sufficient length to engage the center terminal and only one of the associated end terminals. An actuator mounts the slides for movement between a first position wherein the slides electrically couple each of the center terminals with one of its associated end terminals and a second position wherein the slides electrically couple each of the center terminals with the other of its associated end terminals. A light emitting element has a pair of electrodes and is responsive to a given voltage across the electrodes for emitting light. The actuator comprises an actuator body having a recess for mounting the light emitting element therein for observing the presence or absence of light therefrom during operation of the slide switch, and guides for guiding the pair of electrodes into position for electrically conductive contact respectively with the selected ones of the slides.

The invention relates generally to the field of electrical switches and more particularly to a novel slide-type electrical switch including an indicator light adapted to be energized when the switch is in at least one position so as to indicate the condition of the switch.
Many electrical switches include visual indicators to indicate the condition or position of the switch. Some such indicators include light elements mounted to the switch in some fashion and these elements may comprise relatively small lamps or light emitting diodes (LEDs).
In slide switches, one or more selected terminals may be engaged with selected other terminals by action by a sliding contactor or "slide" element which slides in a linear direction over the terminals in response to linear sliding movement of an actuator member. The terminals are arrayed in parallel rows to be simultaneously contacted by a plurality of such slides in response to movement of the actuator member, such as a button or knob. While some arrangements have been proposed heretofore for providing a lamp or LED as an indicator for such a switch, these arrangements have been relatively complicated and expensive, requiring extensive modification of existing slide switches and specialized parts, tooling and the like in their manufacture.


In a compensating membrane carburetor having a fuel accumulating chamber connected through idling and high-speed jets to a Venturi, a compensating chamber is provided which is maintained, naturally or artificially, at atmospheric pressure. A second chamber seals the external face of the compensating membrane from the environment of the carburetor and a first relief line, partially disposed in the carburetor, provides fluid communication between the compensating chamber and the second chamber to maintain the second chamber at atmospheric pressure. A second relief line is disposed substantially outside of the carburetor and also provides fluid communication between the compensating chamber and the second chamber, in order to insure the proper operation of the carburetor in the event of a blockage in one of the two lines.

The invention relates generally to carburetors, and more particularly to carburetors of the membrane type.
It is known that carburetors of the membrane type, unlike other types of carburetor, were designed for the purpose of assuring correct operation or the optimum fueling of an internal combustion engine, even when the engine is used in positions ranging from its proper horizontal position to the inverted position.
The membrane carburetors referred to above are used particularly in portable chain saws and in outboard motors on any kind of boats, and in general in all cases in which the internal combustion engine is mounted on machines, devices and equipment which, on account of their particular use, are subjected to constant rocking, tilting or shifting of position. In brief, the membrane carburetors of the known type are essentially provided centrally with a Venturi tube through which air passes to constitute the combustible mixture, and within which the high-speed and idle jets terminate. These jets are connected by appropriate passages, with the interposition of suitable regulating screws, to a fuel accumulating chamber which is supplied by a conventional diaphragm pump. One surface of said diaphragm pump is in contact with the fuel which is drawn from the fuel tank, while the opposite surface faces a chamber which receives the drive pulses from the crank-case of the internal combustion engine.
Furthermore, for the proper operation of the motor, the outside wall of the fuel accumulating chamber is defined by a thin membrane which is connected, through the medium of a suitable rocker arm, to the needle valve which is interposed between the diaphragm pump and the above-mentioned fuel accumulating chamber.
Lastly, the surface of the said membrane which is external to the fuel accumulating chamber is directly in contact with the atmosphere so as to operate at atmospheric pressure, and it is for this reason that this membrane is often called the "compensating membrane."
Although the membrane carburetors of the type treated above, and thus structured and designed, have proven and still prove to be suitable for the uses for which they are intended, they have serious deficiencies, particularly when they must operate under adverse conditions, and more particularly when they are partially or completely submerged in a liquid, which can be, for example, water. In fact, if the internal combustion engine is to operate partially or completely submerged, as for example in the case of a means of propulsion for an underwater exploration or working machine, in the case of a chain saw to be used in cutting up tree trunks obstructing the banks of a river, in the case, which is often encountered, of operation in a heavy downpour of rain, in the case of outboard motors in general, in the case of a traction and transport means for an underwater explorer or SCUBA diver, and in all cases in which it is required, the compensating action of the carburetor membrane will fail because there is added to the atmospheric pressure, which is optimum for the proper operation of the carburetor, the hydrostatic head, which is defined by the difference in altitude between the free surface of the fresh or salt water or other liquid and the depth reached in this liquid by the said compensating membrane.
The difficulties cited above result, of course, in the complete stoppage of the engine, with the consequences resulting particularly if the internal combustion engine is a propulsion means for an underwater exploration or working machine, or if it is an outboard motor in a boat which is at sea under particularly adverse conditions.
Furthermore, the above-cited difficulties are worsened by the fact that the compensating action of the membrane is further impaired by the relative movements which take place between the liquid and the membrane due to the movement of the internal combustion engine relative to the liquid, or on account of the movement of the said liquid with respect to the virtually stationary engine; that is to say, in this case, there is added to the atmospheric pressure a hydrodynamic head which, of course, is greater than the hydrostatic head. Furthermore, these difficulties become much more evident in the case of liquids of greater specific gravity, such as salt water or muddy water, industrial liquids or industrial waste liquids which, in comparison with fresh water, present a hydrostatic or hydrodynamic head that is certainly greater than that of fresh water.
In view of what is said above, it certainly is not necessary to direct attention to all the consequences which result from the above-stated difficulties and which result in the stoppage of the internal combustion engine.
In a pending application, Ser. No. 002,041 filed Jan. 5, 1979, now U.S. Pat. No. 4,230,646, a device is disclosed particularly adapted for carburetors of the compensating membrane type for eliminating the difficulties cited above and assuring the proper operation of the internal combustion engine even when the latter is partially or completely immersed in any liquid, particularly water.
The basic concept of that device is to provide a compensating air bag or chamber, connected to a conventional compensating membrane of the carburetor, which will be disposed inside of the internal combustion engine or externally thereof, so as to be reliably influenced only by the atmospheric pressure, maintained in a natural or artificial manner, which is the optimum pressure for the correct operation of the internal combustion engine.
It has been found, however, if atmospheric pressure is not freely communicated to the atmospheric side of the compensating membrane, that is to say if there is any blockage such as any liquid or solid of sufficient quantity and quality to restrict the free flow of compensating atmospheric pressure within any part of the chamber formed around the compensating membrane, it will lose its ability to compensate for the varying pressures on the fuel side thereof and thereby will cause the inlet control needle of the carburetor to open and close out of harmony with the demands of the engine. This situation, depending on the degree of blockage, will cause the engine performance to deviate from normal in degrees from erratic loss of power due to slightly more fuel flow than what is required, to complete engine shutdown due to, most often, a profuse fuel flow and subsequent flooding or conversely a stoppage of fuel flow.
If the above-mentioned blockage occurs, the remedy, in most cases, involves removal, partial disassembly, reassembly, reinstallation and pressure testing the carburetor and its appendages. This procedure requires diagnosis and some degree of technical ability, as well as some special tools.


Two-dimensional material based filters, their method of manufacture, and their use are disclosed. In one embodiment, a membrane may include an active layer including a plurality of defects and a deposited material associated with the plurality of defects may reduce flow therethrough. Additionally, a majority of the active layer may be free from the material. In another embodiment, a membrane may include a porous substrate and an atomic layer deposited material disposed on a surface of the porous substrate. The atomic layer deposited material may be less hydrophilic than the porous substrate and an atomically thin active layer may be disposed on the atomic layer deposited material.

Many industries and applications, such as water purification, chemical synthesis, pharmaceutical purification, refining, natural gas separation, and many other applications rely on energy-intensive membrane separation as a major component of their processes. The need for membranes with high selectivity and flux for both liquid-phase and gas-phase membranes has led to many improvements in ceramic and polymer-based membranes over the past few decades. One of the primary challenges has been maximizing flux while maintaining high selectivity. Typically, increasing flux rate necessitates a decrease in selectivity. While several decades of research has resulted in development of polymeric or ceramic membranes, further advances in membrane technology will likely rely on new membrane materials that provide better transport properties. Recent advances in two-dimensional (2D) materials such as graphene have opened new opportunities to advance membrane technology, where these 2D materials can form the active layer that confers selectivity.

King Fahd University of Petroleum & Minerals


An exemplary system method, and computer-accessible medium for initiating a protocol(s) can be provided, which can include, for example, generating a digitally encrypted perishable object(s), distributing the digitally encrypted perishable object(s) to a cyber-physical entity(s), determining if the cyber-physical entity(s) has received the digitally encrypted perishable object(s), and initiating at a predetermined protocol(s) based on the determination.

Current trends in technology point to increasing ubiquity of "social-network" and "application" centric frameworks. While these trends have dramatic security implications, which highlight the need to detect deceptive behaviors, it can also underscore the importance of developing new methods for malware detection and deterrence.
One of the problems facing the agents of a social-technological network can be to identify and classify the various forms of deception and attacks in traces executed on end point devices. Just as attackers can employ deception to achieve an attack (e.g., a benign sounding flash light app that actually opens a back door on the end point device to surveil the device's GPS coordinates, (see, e.g., Reference 1)), a defensive user can also check and validate that an app abides by a specific system security property, such as non-surveillance, which could be validated on the end point device by use of a trace monitor. The transactions in social-technological networks embody many such repeated games, with payoffs and costs, as in the previous example in which the sender of the flash light app receives the benefit of asymmetric information relative to each receiving agent (e.g., each end point device which installed the flash light app). The receiver can incur a cost through both the loss of privacy, and unawareness of the asymmetric information exploited by the sender.
Technical approaches toward attaining cyber security have created pressure on malware attackers to evolve technical sophistication and harden attacks with increased precision, including socially engineered malware, and distributed denial of service ("DDoS") attacks. A general and simple design for achieving cyber security remains elusive, and addressing the problem of malware has become such an important task, that technological, economic and social forces are needed to address this problem.
For example, in March of 2013, an attacker issued a DDoS attack that was so massive, it slowed internet speeds around the globe. Known as Spamhaus/Cyberbunker, this attack clogged servers with dummy internet traffic at a rate of about 300 gigabits per second. By comparison, DDoS attacks against banks typically register only about 50 gigabits per second. The Spamhaus attack came 13 years after the publication of best practices on preventing DDoS attacks, and it was not an isolated event.
Recent figures indicate that cyber-attacks continue to rise. Research from the security firm Symantec indicates that in 2012, targeted cyber-attacks increased by 42 percent. In part, for example, existing technologies facilitate the role of attacker over the role of defender, since in this hide-and-seek game, the tricks to hide the attack are many, whereas the techniques to seek them are meager and resource intensive.
The feasibility of the recommendation-verification system opens the way to new defense mechanisms that can be scalable to populations of users in a social-technological network in the era of ubiquitous computing.
Behavior modeling of agent based populations in cyber-social systems via signaling games was previously introduced, (see, e.g., Reference 2); this was later extended to minority games with epistatic signaling. Both simulation studies can be used to understand how a recommendation-verification system can operate practically. In signaling games, the parameters of costs/payoffs were shown to have dramatic outcomes on expected system (e.g., of population of agents) behavior. Epistatic signaling games, where defense options consider a vast attack surface, can provide more realistic simulations, yet retain many of the dynamics discovered in signaling games. The system wide effects of an early adapter advantage was explored in the minority game variation. This facilitates the exploration of the effects of preferentially rewarding early challenging receivers who adapt effective defenses in response to an ongoing attack technique, an important condition for any system that provides incentives for challenges to adapt (e.g., via mutation or other means) to novel attacks. Further exploration investigated the use of strong and transparent metrics for scoring security challenges (e.g., properties), and how this can lead to a more effective population wide response to emerging attacks. While the simulation studies address population behavior and dynamics, the question of how to implement such a system remained open, and it can be demonstrated how to challenge options for a recommendation-verification system could be realized with a methodology that learns the properties of traces from a particular malicious code family Zeus/Zbot (referred to as Zeus).
Formal methods including model checking, properties (e.g., as sets of traces) and hyper-properties (e.g., as sets of properties), can be referenced as ways forward to address the growing problem of malware and cyber security in today's ecology of computing. (See e.g., Reference 3). Hyper properties can also be used as a potential means to formally describe attack behavior and malicious use cases. Hyper properties can be shown (see e.g., Reference 4) to compactly describe security properties, such as non-interference, where a guarantee can be described as a hyper property. Such challenge options could be realized on end point devices by the use of trace monitors. To facilitate the needs of recommendation-verification, detectors (e.g., challenge options) can be described in a formal and standard way that can also be human interpretable. Therefore, hyper properties can be an ideal format.
The use of machine learning in the area of cyber security can be prevalent. (See, e.g., References 5-8). In this exemplary approach, machine learning methods can be used which can produce interpretable models (see, e.g., References 10 and 11), which develops procedures for inducing a simple and interpretable model from structured features (see, e.g., Reference 12) for boosting a classifier by combining an ensemble of weaker learners, and for ensemble boosting for interpretable decision trees. (See, e.g., Reference 13).
The exemplary technique illustrated on Zeus can be related in subject to previous work (see, e.g., Reference 7), which confines the learning objectives to features obtained from traditional runtime behavioral observations. A trace based approach can be pursued, which can construct an analogous analysis technique, but can limit the feature space to API count profiles, and stop short of measuring critical performance metrics (e.g., including model complexity) which would be utilized in a distributed recommendation-verification system. (See, e.g., Reference 6). The learning objective can be extended from the feature space of API count profiles to a feature space that includes primitive features (e.g., k-mers) of local ordering (e.g., of function call sequences), and the outcome suggests that this extension can lead to more concise and low complexity models. It can be further shown how to translate the results to a formal property, which could be deployed in a federated response.
By revisiting the problem of machine learning malware families from trace data, an immediate and promising possibility for development of receiver challenges in a practical recommendation-verification system can be explored.
A previous publication has pointed out that "[t]he need to secure computational infrastructure has become significant in all areas including those of relevance to the DoD and the intelligence community. (See e.g., Reference 3). Owing to the level of interconnection and interdependency of modern computing systems, the possibility exists that critical functions can be seriously degraded by exploiting security flaws. However, while the level of effort expended in securing networks and computers can be significant, current approaches in this area overly rely on empiricism and can be viewed to have had only limited success." The following rationale was offered: the challenge in defining a science of cyber-security derives from the peculiar aspects of the field. The "universe" of cyber-security can be an artificially constructed environment that can be only weakly tied to the physical universe.
Thus, the difficulty in developing a science of cyber security ("SCS") can be thought to stem from its inherent Manicheanness, where the adversary can be strategic and utilitarian, as opposed to being oblivious and stochastic (e.g., Augustine). (See e.g., Reference 3). However, it must also be noted that a significant fragment of a SCS has to be built upon a complex computational infrastructure that can be amenable to reasoning and re-engineering based on logical models, such as Kripke structures. Thus, it appears that a successful approach to the cyber security problem can come from an amalgamation of a dualistic approach, which can be partly based on techniques from game theory (e.g., inspired and validated with the tools of systems biology, (e.g., analysis of immune systems) and partly based on model building (e.g., machine learning and statistical inference) and model checking. In light of this discussion, it can be worth re-examining the strategic choices that entities such as SPAMHAUS and CYBERBUNKER made, despite the obvious fact that both parties must have been well-informed about the accepted norms and best practices that were incorporated in the hardware, software and protocol architectures; divorced from a model of the humans and the utilities they wished to derive from their strategic choices, the protocols, practices and norms achieved precious little.
Cyber security can be thought of in terms of classical Information-Asymmetry Games (e.g., also called Signaling Games) (see, e.g., Reference 3), where the players (e.g., agents) can assume either a role of a sender ("S") or that of a receiver ("T"). The sender can have a certain type, t, for instance: beneficent (e.g., "C" for cooperator) or malicious (e.g., "D" for defector), which could be assumed to be given by nature. The sender can observe his own type while the receiver does not know the type of the sender. Based on his knowledge of his own type, the sender chooses to send a message from a set of possible messages M={m1, m2, m3, . . . , mj}; these messages can be complex, for instance, an offer of a mobile app with certain advertised utility and a price. The receiver can observe the message, but not the type of the sender, or the ability to fully verify the message. Then, the receiver can choose an action from a set of feasible actions A={a1, a2, a3, . . . , ak}; the receiver can be oblivious/trusting (e.g., C for cooperator) or vigilant/mistrustful (e.g., D for defector). For instance, the offer of a mobile app can be ignored, accepted, or verified and rejected, with a possibility of a reputation-labeling of the app, the sender or the app-store, etc. The two players can receive payoffs dependent on the sender's type, the message chosen by the sender and the action chosen by the receiver.
Because of the informational asymmetry, it can be possible for a sender to be deceptive, as can often be the case in the cyber context. Traditional techniques such as making the signaling somewhat "costly" for the sender can help, but must be engineered carefully, otherwise the very information-sharing capabilities of the cyber system can be seriously compromised. There have been proposals for a new internet architecture, new internet protocols and "bandwidth-as-price" mechanisms (see, e.g., References 1, 2, 4, 5, 7-9, 16, 18 and 19), but any such approach can burden the normal transactions with an unwelcome and unacceptably heavy overhead.
At the center of many dynamic online strategic interactions (e.g., in social-technological networks) can be simple information-asymmetric games. Each interaction among agents, exchanging digital messages or Apps, presents a chance that either party can employ deception, and gain advantages over the other. Take for example the flash-light App for smart-phones which was also discovered to open a GPS-tracking backdoor to gain private information by tracking the device's physical location. (See e.g., Reference 1). While the producer (e.g., sender) of the flash-light App can advertise (e.g., signal) that the application can be designed to provide a flashlight feature (e.g., for smart phones) the sender creates the deceptive impression of respecting the user's privacy as implied by the app's benign sounding name: "flash-light App." Typical user's expectations of privacy would proscribe the surveillance capabilities (e.g., physically tracking the user's device via GPS-tracking) and not foresee encroachment by an app that can be prima facie simple, benign and desirable. In this case (e.g., and others like it) a typical consumer (e.g., receiver) would recognize that they had been deceived upon discovery of the App's true scope of capabilities which include the GPS-tracking, and subsequent to the discovery of the deceptive attack, the receivers can label the sender as a miscreant, and tarnish their reputation with a negative ranking and comments sprinkled with such labels as "backdoor," "Trojan," or "Malware." The encounter, concluded before the discovery of the attack, has its costs and benefits, as the cost to the receiver can be the loss of privacy, and the benefit to the sender can be the ability to gain strategic informational advantages with unanticipated usages.
Thus, it may be beneficial to provide an exemplary system, method and computer-accessible medium that can overcome at least some of the deficiencies described herein above, and provide, for example, malware deterrence.

System, method and computer-accessible medium for deterrence of malware


A receiver having an RF section, a mixer stage and a signal processing stage, the mixer stage receiving a mixing frequency from a frequency synthesis circuit which includes a phase-locked loop provided with a phase detection device having a current output, a loop filter including a .pi.-shaped RC network having an input shunt path and an output shunt path which are connected to respective ends of a series resistor incorporated in a series path, and to ground, and include first and second capacitances, respectively, and with a voltage-controlled oscillator, a reference frequency being applied to the phase detection device. In order to prevent the use of active filter circuits in the phase-locked loop of such a receiver, the second capacitance is chosen to be at least twice as large as the first capacitance, the series resistance is chosen to be smaller than the output impedance of the phase detection device and the output shunt path of the loop filter is provided with an RC phase shift member for reducing the phase shift of the second capacitance in the output shunt path.

1. Field of the Invention
The invention relates to a receiver comprising an RF section, a mixer stage and a signal processing section, said mixer stage receiving a mixing frequency from a frequency synthesis circuit which comprises a phase-locked loop provided with a phase detection device having a current output, a loop filter comprising a .pi.-shaped RC network having an input shunt path and an output shunt path which are connected to respective ends of a series resistor incorporated in a series path, and to ground and comprise first and second capacitances, respectively, and with a voltage-controlled oscillator, a reference frequency being applied to said phase detection device.
2. Description of the Related Art
A phase-locked loop for use in a frequency synthesis circuit of such a receiver is known per se, for example from U.S. Pat. No. 3,316,497.
In the known phase-locked loop, the controlled oscillator is coupled to the phase detection device via a frequency divider. The reference frequency is also applied to the phase detection device from, for example, a crystal oscillator. In the phase-locked state of the loop, phase difference between the frequency-divided oscillator signal, on the one hand, and the reference frequency, on the other hand, are converted in the phase detection device into a phase difference signal which is negatively fed back in the loop from the output to the input of the phase detection device and is thereby suppressed. As a result, an accurate phase synchronization of the frequency-divided oscillator signal with the reference frequency takes place in this phase-locked state and the oscillator frequency is a factor determined by the dividend or division factor of the frequency divider multiplied by the reference frequency. By varying said dividend, the oscillator frequency, which is applied as a mixing frequency to the mixer stage, can be adjusted to a desired tuning frequency.
For a correct operation of the phase-locked loop, the loop parameters should satisfy conflicting requirements: for example, the loop selectivity is to be chosen as large as possible for a maximal phase synchronization. However, a large loop selectivity is accompanied by a large phase shift which jeopardizes the loop stability. The impedance levels should also be noiselessly adjusted to correct values so as to prevent the loop circuits from influencing each other.
In the known phase-locked loop, use is made of active filter sections for this purpose, which, together with said .pi.-shaped RC network, form part of a loop filter. In these active filter sections, capacitances, series resistors and operational amplifiers ar used for amplifying and selecting a dc control signal for the voltage-controlled oscillator. Particularly because of the series resistors and the amplifiers, the use of such active filter sections in a phase-locked loop introduces a number of unwanted effects in the loop, such as:
the occurrence of unwanted sideband signals around the oscillator frequency at intervals with the order of magnitude of the reference frequency, caused by leakage currents in the amplifiers; PA0 an unwanted frequency modulation of the oscillator signal as a result of insufficient suppression of power supply voltage variations or ripple in the amplifiers; PA0 noise which becomes manifest as an unwanted sideband noise in the oscillator signal.

Receiver having PLL frequency synthesizer with RC loop filter


A vascular access sheath is provided for introducing catheters, stents, and other interventional devices into blood vessels. The invention comprises a stiff tubular catheter segment, which is designed to remain outside the body, having two hemostatic valves, most preferably of an iris valve design disposed at each end. A flexible sheath extends from one of the valves for insertion into the blood vessel. In operation, the valves are opened and closed one at a time, to allow relatively large devices to be introduced into the blood vessel without the valve pressing against the devices and with minimal loss of blood.

Currently existing vascular sheaths were initially designed to safely and easily introduce angiographic catheters of relatively small diameters, e.g., 4-7 French (1.3-2.3 mm) percutaneously into arteries and veins. The advent of angioplasty balloon catheters led to the development of sheaths having inner diameters as large as 8-9 French (2.6-3.0 mm) to accommodate the early large balloon catheters. The basic design of the hemostatic valve typically provided at the proximal end of the sheath has changed only minimally during this time, the modifications being in materials and minor changes to improve hemostasis.
As familiar to those of skill in the art, the introduction of vascular stents (Palmaz, Wallstent, Strecker, Gianturco), percutaneously inserted vena cava filters (Titanium Greenfield, Bird's Nest, Simon Nitinol LGM Venatech), and atherectomy catheters (Simpson, T. E. C.) stimulated the development of vascular sheaths ranging in inner diameter from 10 to 14 French (3.3 to 4.6 mm). These larger sheaths have been designed either with the same hemostatic valves as the original smaller sheaths, or without a valve at all in the case of certain filter sheaths, since these latter sheaths are placed in the lower pressure venous system.
It has become apparent that passing stents and atherectomy catheters through the original-design hemostatic valve into the arterial system requires a stiff cylindrical sleeve to open the valve and prevent damage to the stent or atherectomy catheter as it passes through the valve. This is both cumbersome and results in a momentary massive blood leak under arterial pressure, as hemostasis is lost because the valve is opened by the sleeve.
U.S. Pat. No. 4,580,573 to Quinn and U.S. Pat. No. 4,540,411 to Bodicky both disclose catheter introducers having a single elastic valve. Such valves are designed to press tightly against a catheter as it is inserted and thereby attempt to prevent blood loss. Such valves have been found, however, to be inadequate for introducing stents and filters, which would be damaged by such pressure. On the other hand, if such valves are left open as devices are passed through them, a significant loss of blood would occur. U.S. Pat. No. 5,0009,391 to Steigerwald discloses a valve assembly for introducing catheters having two elastic disc valves. The discs are normally closed, but permit a catheter to pass through them while pressing tightly against the catheter. However, as was the case with other elastic valves described above, these designs are inadequate for introducing stents and filters since these devices would be damaged by such pressure.
A need therefore remains for a vascular sheath for introducing interventional devices into the vascular system, without pressing tightly against the interventional device as it is inserted while preventing a significant loss of blood.

Vascular access sheath for interventional devices