Efficient, low threshold laser emission from a laser crystal doped with chromium and neodymium ions is obtained when pumped by visible laser diodes in the range of 610 nm to 680 nm. A typical laser Cr,Nd:GSGG crystal having an extraordinarily broad absorption bandwidth allows high pump efficiencies when using visible laser diodes, particularly in comparison to the Nd:YAG laser. The broad absorption bandwidth tolerance of the Cr,Nd:GSGG crystal to the pumping wavelengths allows visible diode pumping of the neodymium transition without regard to the wavelength of the visible diodes. Longitudinal or end-pumping to take advantage of the emission properties of the visible laser diodes, a nearly hemispherical laser resonator configuration and other co-doped Cr,Nd laser host materials are disclosed. Consequently, costs are reduced for the semiconductor pump as well as producing a compact, efficient, lightweight and reliable laser previously unachievable with other types of laser or lamp pumping. As an improvement in a laser pumped Cr,Nd:GSGG laser, diode pumping brings the advantages of high electrical to optical efficiencies and compact design. End-pumping with the visible diodes allows efficient utilization of the visible laser diode pump light and further allows a more ideal overlap between the inversion profile created within the laser crystal by the pump fluence and the TEM.sub.00 resonator mode extracting fluence.

The present invention relates to lasers and particularly to a laser diode pumped solid state laser for producing laser emission at one or more laser wavelengths.
Lasers are devices that generate or amplify light. The beams of radiation that lasers emit or amplify have remarkable properties of directionality, spectral purity and intensity. These properties have already led to an enormous variety of applications. The essential elements of the laser device are (1) a laser medium consisting of an appropriate collection of atoms, molecules, ions or, in some instances, a semiconducting crystal; (2) a pumping process to excite these atoms, molecules, etc., into higher quantum mechanical energy levels; and (3) suitable optical feedback elements that allow a beam of radiation to either pass once through the laser medium that is in a laser amplifier, or bounce back and forth repeatedly through the laser medium, as in a laser oscillator. The laser contains an optical cavity or resonator which is defined by highly reflecting surfaces which form a closed round-trip path for light. The laser medium is contained within th optical cavity.
The elements of a laser come in a great variety of forms and fashions. One type of laser medium that has numerous advantages compared to others is the solid state laser medium consisting of a laser crystal with one or more dopant ions that is, generally, optically pumped. The optical pump may be an incoherent source, such as cw lamps, including tungsten filament lamps or arc lamps, or pulsed lamps, such as flashlamps, or a monochromatic laser source. Monochromatic laser pump sources include ion lasers or dye lasers or semiconductor laser diodes, such as, an aluminum gallium arsenide (AlGaAs) laser diode operating at approximately 808.5 nm pumping a Nd:YAG solid state laser material. As an example of this type of laser, see the article "Efficient Laser Diode Pumped Nd Lasers" by Richard Scheps in Applied Optics, vol. 28, pp. 89-91 (January 1989).
In order for the optical pumping process to be effective, the photons incident on the laser medium must have certain properties. In particular, the pump radiation must be of a wavelength which is absorbed by the laser medium to generate either directly or indirectly the required population inversion for the desired laser transition.
Laser diode pumping of Nd:YAG lasers is well recognized. The laser diode output radiation must substantially match the desired absorption wavelength of the Nd:YAG laser medium, which in general, corresponds to a wavelength of 808.5 nm. This matching of the laser diode emission wavelength with the absorption wavelength and bandwidth of the Nd:YAG laser material at 808.5 nm is required for relatively efficient operation, both in terms of pumping efficiency, by which is meant the efficiency by which pump photons populate the upper laser level, and in terms of overall electrical power consumption by the pump diodes themselves to generate a specific amount of optical laser power from the Nd:YAG laser material. The absorption bandwidth of Nd:YAG is approximately 1 nm. It is both difficult and expensive to fabricate laser diodes or laser diode arrays with the proper power, bandwidth and center wavelengths required for efficient pumping of Nd:YAG laser media.
The typical AlGaAs semiconductor material pumping diodes have a naturally broad wavelength range over which they can produce radiation. That is to say, although the bandwidth of an individual AlGaAs semiconductor laser is relatively narrow, the center wavelength can vary over 50 nm or more from one device to another. This is due, partially, to the fact that the center wavelength is highly sensitive to the aluminum concentration in the AlGaAs active layer. An additional problem for AlGaAs laser diode pumping of Nd:YAG lasers is that the junction temperature of the pump diode requires accurate thermal control for efficient operation of the Nd:YAG laser due to the narrow absorption bandwidth at 808.5 nm since there is a well known shift of the semiconductor laser central wavelength of approximately 0.3 nm per degree Centigrade change in junction temperature.
Because the nature of the semiconductor laser diode is such that approximately 60 percent or more of the electrical power used to drive the diode is dissipated in the diode junction as heat, junction temperatures will rise dramatically as the device is turned on. Thermal control, therefore, is extremely important in terms of maintaining the appropriate temperature of the semiconductor diode junction to produce the proper center wavelength for the laser diode. Practical operating temperature ranges run generally from 10.degree. C. to 30.degree. C., and since center wavelength shifts with junction temperature of 0.3 nm per degree C., the 20 Centigrade degree operating temperature range for the semiconductor diode laser can produce at most a 6 nm shift in wavelength. Therefore, if the semiconductor laser diode that is intended to pump the Nd:YAG laser gain medium is not within just a few nanometers of 808.5 nm, then it is impractical to resort to cooling or heating of the semiconductor laser diode to try to achieve the proper emission wavelength from the semiconductor laser. In addition, control of the diode junction temperature over a range of semiconductor laser diode pump powers is cumbersome and adds complexity to the overall system.
The narrow absorption linewidth of Nd:YAG also increases the difficulty of modeling both the inversion profile resulting from volumetric deposition of the polychromatic pump excitation as well as modeling the effects of anticipated spectral shifts in the pump source due to aging; see for example of R. Scheps and J. F. Myers, "Performance and Aging of High Powered 2-D Laser Diode Arrays," Applied Optics, vol. 29, p. 341 (1990).
While individual laser diodes may have their central emitting bandwidth adjusted by temperature control of the junction, this capability does not apply to laser diode arrays that are used as the pumping source. These arrays generally consist of multiple semiconductor laser diode stripes on a single monolithic semiconductor laser substrate. The bandwidth and central wavelength variation from stripe to stripe must be considered and generally leads to a much broader emission bandwidth and a much less well-defined central bandwidth. From a pragmatic viewpoint, a specification requiring a high power, narrow band diode pumping array dramatically increases the cost of purchasing such a pump. Because, in practice, the diode pump array is often the single most expensive component in the laser head, the total cost can easily become prohibitive.
To address the issue of cost effective pumping, hosts for the Nd ion have been sought in which the width of the 800 nm absorption spectrum is increased. Two examples of such host materials are Nd:BEL, see the article by R. Scheps et al., "End-Pumped Nd:BEL Laser Performance," in Optical Engineering, vol. 27, p. 830 (1988), and Nd:YVO.sub.4 ; see the article of R. A. Fields et al., "750 mW, 1.06 .mu.m cw TEM.sub.00 Output from a Nd:YVO.sub.4 Laser End Pumped by a Single 20-Stripe Diode Array," in Advances in Laser Science-III, American Institute of Physics Conference Proceedings, Atlantic City, N.J., Vol. 172, pp. 20-22 (1987). Both of these Nd doped crystals have been diode pumped and have a significantly broader absorption bandwidth than Nd:YAG.
While Nd:BEL and Nd:YVO.sub.4 may be promising, the largest practical absorption bandwidths for singly doped neodymium crystals are on the order of 5-10 nm at the 800 nm emission bandwidth for AlGaAs semiconductor laser diodes. The search for hosts where a neodymium absorption band is broader generally has led to materials where the neodymium emission cross-section is drastically compromised to the point where the emission becomes highly inefficient. In other words, although the pumping efficiency has increased, (a greater fraction of the pump photons are absorbed by the gain medium and subsequently populated the upper laser level), the extraction efficiency, (the ability to utilize the inverted population to produce laser emission), has been lowered dramatically.
An alternative approach to achieve high pump efficiency while maintaining high extraction efficiency is to co-dope the neodymium host material with an activator ion such as Cr.sup.3+. By co-doping with chromium, the very broad absorption spectrum in the red (near 660 nm) can be advantageously utilized to increase the pump efficiency. Co-doping also improves the efficiency for flashlamp pumping. An example of a flashlamp pumped design is given in U.S. Pat. No. 4,837,769 by S. Chandra et al. called "Phase Conjugated Slab Laser Designator." See also the article by A. A. Kaminskii et al., "Luminescence and Stimulated Emission of Nd.sup.3+ Ions in Gd.sub.3 Sc.sub.2 Ga.sub.3 O.sub.12 Crystals," Physics Status Solidi (a), vol. 34, p. K109 (1976). Relative to Nd.sup.3+ the Cr.sup.3+ ion absorbs most of the pump photons and is excited to the .sup.4 T.sub.2 state. The excited Cr.sup.3+ ion subsequently undergoes a rapid and efficient excitation transfer between the .sup.4 T.sub.2 state of Cr.sup. 3+ and the .sup.4 F.sub.3/2 Nd level. The .sup.4 F.sub.3/2 Nd ion excited state is the upper laser level. This excitation transfer process therefore directly populates the upper laser level of the neodymium ion, from which lasing at 1.06 .mu. is observed.
The efficiency of transfer of energy from the Cr.sup.3+ ion to the Nd.sup.3+ ion has been measured to be 87 percent, by which it is meant that 87 percent of the pump energy which is initially absorbed by the Cr.sup.3+ ion is transferred to the upper laser level of the Nd.sup.3+ ion. Some of the excitation that initially resides in the Cr.sup.3+ ion is lost through fluorescence, but it is to be noted that the Nd.sup.3+ ion has strong absorption bands in the same spectral range as the Cr.sup.3+ fluorescence. Therefore, an additional excitation transfer process occurs through absorption of the Cr.sup.3+ fluorescence by the neodymium ion.
Previous results on laser operation of a Cr,Nd:GSGG laser have been reported. The host GSGG is gadolinium scandium gallium garnet and has the chemical formula Gd.sub.3 Sc.sub.2 Ga.sub.3 O.sub.12. A report by D. Pruss et al., "Efficient Cr.sup.3+ Sensitized Nd.sup.3+ GdScGa-garnet Laser at 1.06 .mu.m" which appeared in Applied Physics B, vol. 28, p. 355 (1988) identified the mechanism for excitation transfer. Only a krypton ion laser was used as the pumping source which emitted radiation at 647.1 nm. The use of a krypton ion laser make applications of a laser pumped Cr,Nd:GSGG laser based on the work of Pruss et al. highly impractical since for one thing, the ion laser is less than 0.01 percent efficient in terms of converting electrical efficiency to optical output. The krypton ion laser requires enormous cooling power and very high amperage laser drive current, typically over 100 amps at 220 volts to operate the ion laser. In addition, the pumping laser is very large and easily damaged because it contains a glass plasma tube so that portability, compactness and other features which might otherwise make this device more useful cannot be achieved with a krypton ion pump.
U.S. Pat. No. 4,740,975 by Abrahams et al. and U.S. Pat. No. 4,802,180 by Brandle, Jr. et al. also have discussed a laser pumped Cr,Nd:GSGG laser. Both of these patents are similar and focus on addressing the concepts of growing the laser medium crystal itself and specific techniques required to grow defect-free co-doped Cr,Nd:GSGG laser crystals. Both patents are slab-shaped designs to be side pumped and completely overlook the concept of an end-pumped Cr,Nd:GSGG laser.
There have been numerous patents issued for the concept of laser diode pumped neodymium doped lasers. Two patents have specifically mentioned diode pumped Cr,Nd:GSGG lasers. These are U.S. Pat. No. 4,901,330 by Wolfram et al. and U.S. Pat. No. 5,029,335 by Fisher et al. The Wolfram patent is concerned with generating optically pumped radiation from a laser diode array and mentions co-doped Cr,Nd:GSGG as a possible laser medium which can be utilized. However, the particular invention of Wolfram et al. would preclude good end pumping. More importantly, Wolfram et al. overlook the fact that the AlGaAs diodes which were used in the neodymium pumped laser materials, which will emit in the 800 nm range, are entirely useless for the co-doped material in the sense that they only pump the neodymium ion. These AlGaAs diodes, because of their emission bandwidth, can only pump the neodymium in the co-doped Cr,Nd:GSGG and cannot excite the Cr.sup.3+ ion. Furthermore, Wolfram et al. fail to acknowledge that different pump wavelengths are required for the co-doped material in order to take advantage of the broad absorption band in the visible. Nor do they note the entirely different wavelength dependence and lack of wavelength matching criteria inherent in the Cr.sup.3+ co-doped material relative to the singly doped neodymium materials that they address in their invention.
The Fisher et al. patent describes an improved heat dissipating package for a laser diode pumped neodymium doped laser. It mentions the problems involved in a wavelength mismatch between the pump emission and the laser medium absorption and specifically addresses the thermal shift in the emission wavelength of the pump laser diode that must be controlled adequately to maintain high pump efficiency. However, it shows a resonator which does not allow compact, efficient, end pumped operation when pumped by laser diodes. The Fisher et al. patent mentions co-doped Cr,Nd:GSGG as a potential laser medium which would be suitable in their inventive concept. The lack of sensitivity of the pump efficiency to the pump wavelength is not mentioned in the Fisher patent which is a benefit of using the co-doped material. The lack of wavelength sensitivity afforded by co-doped materials may obviate the need or motivation for Fisher et al.s' temperature compensation scheme. That is, although heat removal is nearly always a design consideration, the invention described by Fisher et al. is for the rapid and efficient removal of heat from the laser diode in order to match the laser diode wavelength to the narrow absorption linewidth in neodymium. Considering the broad absorption linewidth of chromium in the visible region of the spectrum, there is little, if any, need to control the wavelength of such a co-doped Cr,Nd:GSGG diode by thermal means.
An example of the types of problems which arise when dealing with the very narrow absorption bandwidth in neodymium doped materials, coupled with the broader emission profile and the shift in central wavelength for laser diodes, is represented in U.S. Pat. No. 4,942,582 by Kintz et al. This patent demonstrates a high output power laser which operates in a single longitudinal mode. Such operation is achieved because the end pumped laser diode fluence is absorbed in a very short axial distance within the crystal near the face that is pumped. In order to accomplish this, a laser diode source with a very narrow bandwidth is needed as the absorption depth in the crystal must be narrow. This requirement, of course, makes the selection of the diode and the operating conditions under which effective pumping of this material can occur (such as junction temperature) much more constrained and more complex, and as a consequence less efficient.
Thus in accordance with this inventive concept a need has been recognized for a neodymium laser that can be diode pumped with a high pump efficiency but is insensitive to the exact pump wavelength and bandwidth of the pump diodes.

Compact, efficient, scalable neodymium laser co-doped with activator ions and pumped by visible laser diodes

The United States of America as represented by the Secretary of the Navy


Queries which may be expressed in natural language are processed by: decoding a query into one or more semantically meaningful query elements;                accessing data storage, which data storage includes at least one annotation element and one or more corresponding data entries: identifying annotation elements in accordance with the semantically meaningful query elements; and retrieving at least one data entry corresponding to each identified annotation element.

1. Technical Field
The present invention relates to a method and apparatus for processing queries and is suitable particularly, but not exclusively, for inputting queries to, and receiving information from, a database.
2. Related Art
The gathering and disseminating of information now forms a vital part of many business processes. These activities usually fall into three parts:
Collect, filter and sort raw information; understand the information, make recommendations based thereon; explain and communicate these recommendations to people. The issues involved in the first stage, that of information gathering, have received a great deal of attention, and continue to be the subject of considerable research around the world. In comparison, the third state, where information is communicated to others, has received relatively little attention. As the transfer of information is often a continuation of significant efforts in the early stages of information dissemination, there is a significant impetus to build on these efforts so that any preliminary work is not wasted. It is vital that the results of such a third state are presented in clear and accessible formats so that recipients of information can derive maximum benefit from the information.
Traditionally, information has been presented through reports. Recent technological developments such as the Internet and intranets have made it much easier to distribute such sources of information, but this benefit of accessibility incurs problems associated with the increased volume of information. Thus there is now such a huge amount of material available that it is difficult to know what is relevant and accurate. Search engines provide a means of retrieving documents that contain particular keywords, or a predetermined combination of keywords, but search results do not include any real measure of how a retrieved document content relates to the keywords. This is mainly a result of the way that documents, which may be books, articles, WWW pages, videos and presentation slides etc. are conceived. These documents often address specific issues or questions, and are typically written for a specific audience. Thus the context of the documents may be vastly different from that of interest to an initiator of a search, despite the fact that there is an overlap of keywords.
There are several systems available that attempt to manage information available from these data sources, and software agents in particular are known to manage information in various predetermined ways. Each agent generally comprises functionality to perform a task or tasks on behalf of an entity (human or machine-based) in an autonomous manner, together with local data, or means to access data, to support the task or tasks. For instance, an information agent might select documents of relevance to a topic or user. A general comprehensive review of agent-based technology is given by Hyacinth S. Nwana, "Software Agents: An Overview" in the Knowledge Engineering Review journal, Vol. 11, No. 3, pages 205–244.
In the Applicant's co-pending international Patent Application Number WO96/23265, there is described a software agent particularly for use in information management. The agent, known as "JASPER", is associated with a user's Internet browser and alerts the user to documents of interest to them. To do that, JASPER uses a keyword set for the user concerned. However, by using clustering techniques, JASPER can extend the keyword set to pick up documents that would not have been located otherwise.
There are also tools known for processing the information itself, such as the PROSUM information summariser described in the applicant's co-pending European patent application number 97302616.4. This summarises information in accordance with a user's particular interest rather than simply in accordance with the content of the document. Hence a user looking at the results of a search and reading the summary produced by PROSUM will be alerted to a document in which the user's interest is represented by only a reference within the document, the document being principally about something else. Such documents tend not to be picked up by more conventional search tools.
Applicant's co-pending Patent Application Number WO99/21108 teaches a system that retrieves objects, such as documents, based on the keyword extraction disclosed in JASPER, and these objects are automatically stored in a database and entered against a user's, or a project's profile. The relationship between any documents so retrieved may be estimated based on criteria such as keyword occurrence, and this estimate is displayed graphically to the user. Access to these documents is a function of information supplied in the respective profiles such that, for example, groups of personnel may automatically be informed of information according to their project group, grade or a security rating as specified in the profiles.
Search engines that are used to search for documents include Yahoo, Alta Vista and Ask Jeeves, among others. The first two, Yahoo, and Alta Vista, search a list of keywords accompanying their index of documents for keywords that match the keywords input by the user. The search is purely a function of keyword 'hits', although at least some of these engines process the query to stem it to its root form. The third system, Ask Jeeves, allows users to phrase queries in natural language rather than entering keywords, and the subsequent search proceeds based on keyword occurrence in the same way as described with respect to the Yahoo engine. Another type of search system is provided by Whatis, which retrieves a text entry in response to a search query; in this system the search is performed on single keywords, and the system displays dictionary entries that correspond to the keywords. The first three of these search facilities discussed above, Yahoo, Alta Vista and Ask Jeeves, provide a user with exactly the problems disclosed above: the user does not know how relevant the document is to his query. The fourth search facility, Whatis, provides a link to single data entries, thus functioning as an electronic paper dictionary, and its use is extremely limited.
U.S. Pat. No. 5,404,295 describes a storage and retrieval system for retrieving selected passages in documents, database entries and the like. These selected passages (subdivisions) are linked to one or more annotations by pointers, and the annotations are stored in a database for querying. Incoming queries are examined against the annotations, in order to identify one or more annotations relevant thereto. When one or more annotations have been identified, the subdivisions relating thereto are retrieved and presented to the user. The presentation and chaining together of subdivisions is implicit in the way in which the annotations and pointers thereto are constructed.

Method and apparatus for processing queries

British Telecommunications public limited company


A tether system for providing thrust to or power subsystems of an artificial satellite in a low earth orbit. The tether has three main sections, an insulated section connected to the satellite, a conducting section connected to the insulating section for drawing in and releasing electrons from the space plasma and a non-conducting section for providing a tension to the other sections of the tether. An oxygen resistant coating is applied to the bare wire of the conducting section as well as the insulated wires of the insulated section that prevents breakdown during tether operations in the space plasma. The insulated and bare wire sections also surround a high tensile flexible polymer core to prevent any debris from breaking the tether during use.

Various tests have verified the utility of electro-dynamic tethers in space such as the Small Expendable Deployer System (SEDS 1 & 2), the Plasma Motor Generator (PMG) and the Tethered Satellite System flights (TSS-1 & TSS-1R). Electro-dynamic tethers, in a relatively vertical gravity-stabilized manner, interact with the magnetic fields of the Earth's or other celestial bodies magnetic fields to produce either electrical power or thrust. These tethers generally consist of a wire extending from a satellite or connected between two satellites, each containing plasma contactors, which are orbiting the Earth or other celestial body. An electromotive force (emf) is induced across the length of the tether.
The emf acts to create a potential difference across the tether by making one end of the tether positive with respect to the other end. In order to produce a current from this potential difference, the tether ends must make electrical contact with the Earth's plasma environment. Both plasma contactors and large conductive surfaces at the ends of the tether provide this contact, establishing a current loop through the tether, external plasma and the ionosphere around the Earth, sometime called a phantom loop. An example of the phantom loop is shown in FIG. 1. Two field lines 13a and 13b representing levels of the magnetic field of the Earth 12 are shown. As the tether 100 connects the field regions 13a and 13b of the Earth 12 in the orientation as shown, the electrons are moved towards the other end, near plasma contactor 300, of the tether, thus charging the ends of the tether, positive near a plasma contactor 200 and negative near plasma contactor 300. When these plasma contactors or conductive surfaces are placed on the ends of the tether, the electrons are free to travel into and out of the tether cable creating charged clouds. As shown in the figure, the collection of electrons from a positive end plasma contactor 200 and their emission from a negative end plasma contactor 300 creates a net positive cloud 14 at the positive end plasma contactor 200 and a negative cloud 15 at the negative end plasma contactor 300. The excess free charges migrate along the geomagnetic field lines intercepted by the tether ends until they reach the vicinity of a lower section of the ionosphere E where there are sufficient collisions with neutral particles to allow the charges to migrate across the field lines and complete the phantom circuit.
Once the current is established within the tether, the combination of the current running through the tether, the tether orbiting about the earth and the geomagnetic field of the Earth react together to create a force that acts on the tether. This force acts in a direction opposite to the movement of the tether across the magnetic field in orbit. An example of this type of electro-dynamic tether is shown in U.S. Pat. No. 6,116,544 (Forward et al.), incorporated herein by reference in its entirety. The tether consists of a wire attached to a spacecraft at one end and attached to an end mass at the other end. The tether is made of a braided aluminum or copper wire. The tether is used to slow the spacecraft down and reduce its orbit.
Another application of the tether is to generate power to either charge batteries on the spacecraft or power spacecraft subsystems. As outlined above, the orbit of the tether across the Earth's magnetic field induces a force on the electrons within the tether wire, which creates a charge separation and produces an electric potential due to Coulomb's law until the forces are balanced by current flow. When the current flow stops, there is a potential difference between one end of the tether and the other. After completing the circuit, the power provided may be used to power spacecraft substations or charge batteries. An example of such a system is shown in U.S. Pat. No. 4,923,151 (Roberts et al.), incorporated herein by reference in its entirety, with the use of a tether extended between two satellites. The tether comprises outer conductive material layers and an inner conductive material layer electrically connected to the tethered object, both separated by an insulator material.
Studies have shown that the use of a bare wire in space would substantially increase the collection of electrons as opposed to the use of conventional plasma contactors. However, a problem with bare wire plasma contactors is that in an oxygen rich environment of a low Earth orbit, the bare wire tethers of copper or aluminum would quickly oxidize and degrade, losing their electro-dynamic properties. Such greatly reduces the effective life of the tether and would require more frequent replacement. Secondly, the Earth's thermal albedo would raise the temperature of the bare wire tether to the point that its resistance would rise, thus decreasing its performance and reducing effective use of the tether.
Another problem with the prior art devices is that the wire constructions are not sufficiently flexible enough to allow a sufficient length of the tether to be wound up in a relative small space on the satellite or spacecraft orbiting a celestial body.

The United States of America as represented by the Administrator of the National Aeronautics and Space Administration


A member for controlling foam in a material reservoir includes a body, a concave space in the body, and wings extending from the body in the concave space. A method of controlling foam in an ink reservoir of a printing system includes rotating a foam control member above ink in the reservoir to dissipate accumulated foam, where the member includes a concave space open toward the ink and wings extending in the concave space.

Printing for a variety of purposes has been indispensable to society for a long time. Printed products are mass produced, produced in-house by large to small enterprises and produced for personal use on home printing systems. Printing enables the sharing of documents, record keeping and many other important functions.
Relatively large-scale or commercial printing systems require relatively large amounts of ink or other printing fluid. The ink is selectively deposited on a print medium, such as paper, to form a printed document.
Because of the large quantity of ink required in some printing systems, ink tanks or reservoirs may be installed to provide the relatively large amount of ink needed for production with such a printing system. Frequently, these tanks are open or loosely sealed at the top so that additional ink can be readily added or ink levels can be monitored by the system operator.
However, as ink is circulated into and out of such tanks, the circulation tends to introduce air into the liquid ink. This causes foaming.
In an open tank, this foam can frequently build up until it overflows the tank. In other cases, the accumulated foam may saturate or penetrate the seal on the tank. In either case, the result is a mess that stains and may degrade equipment as well as a loss of ink that could otherwise be used in the printing process.

System and method for controlling foam in a printing system

Hewlett-Packard Development Company, L.P.


The closable bag with offset end seal comprises a layer of plastic folded over itself to create an elongate strip of interconnected pockets which are separable from one another along the strip to create individual bags. Interposed between free overlying ends of the plastic strip is a gasket made of a heat sealable material having a low surface tension and coefficient of friction. A side edge of these three layers is heat sealed and scored to provide a tamper indicating strip which must be removed to open the bag. Slightly lateral to this strip is a section of the bag where the gasket is heat sealed along its length to one of the layers of plastic, with a remaining inwardly extending portion of the gasket being free to move away from the layer to which it sealed, creating an inwardly directed flap. On a surface of the unattached layer of plastic facing the gasket are provided two spaced apart longitudinal strips of adhesive which cause engagement between the layer of plastic and the gasket flap. Thus, if product within the bag moves toward the seal end of the bag, it rests between the gasket flap and the layer of plastic to which it is heat sealed, without directly resting against the area of closure and compromising effectiveness thereof.

1. Field of the Invention
The present invention relates generally to the automated flexible packaging art. More specifically, the invention relates to a flexible package having improved reclosability and reduced waste in seal areas of the package.
2. Description of the Prior Art
The prior art is replete with examples of reclosable packages which are created as strips of interconnected bags by automated packaging machines.
Examples of such art are found in the following U.S. Patents:
______________________________________ U.S. Pat. No. Patentee ______________________________________ 3,420,433 Bostwick 3,613,874 Miller 3,942,713 Olson et al. 3,990,627 Olson 4,235,653 Ausnit 4,249,982 Ausnit 4,285,376 Ausnit 4,290,467 Schmidt 4,348,440 Kriozere 4,355,494 Tilman 4,441,613 Hain et al. 4,468,811 Shaw et al. 4,502,599 Perecman 4,528,224 Ausnit 4,581,007 Kamp 4,582,549 Ferrell 4,584,201 Boston 4,617,683 Christoff 4,655,862 Christoff et al. 4,691,373 Ausnit 4,706,297 Ausnit 4,709,533 Ausnit 4,785,940 Wilson 4,790,126 Boeckmann 4,846,585 Boeckmann et al. 4,892,414 Ausnit 4,894,975 Ausnit 4,909,017 McMahon et al. 4,912,616 Van Erden 4,925,316 Van Erden et al. 4,929,225 Ausnit et al. 5,007,744 Scarberry et al. 5,023,122 Boeckmann et al. 5,167,455 Forman ______________________________________
As will be described in greater detail hereinafter, the reclosable bag with offset end seal of the present invention differs from those previously proposed by providing heat sealing of plastic to plastic in the seal area, with the seal area being offset from the side end edge of the bag so that items within a reclosed bag do not cause the seal to come undone as happens with side end sealed bags, the seal area further including structure which would provide evidence of tampering, the closure not decreasing the volume within the bag and a gasket flap being provided against which product in the bag can rest, rather than resting directly on the seal and causing a failure thereof.


Optical spectrometers may be used to determine the spectral components of electromagnetic waves. Spectrometers may be large, bulky devices and may require waves to enter at a nearly direct angle of incidence in order to record a measurement. What is disclosed is an ultra-compact spectrometer with nanophotonic components as light dispersion technology. Nanophotonic components may contain metasurfaces and Bragg filters. Each metasurface may contain light scattering nanostructures that may be randomized to create a large input angle, and the Bragg filter may result in the light dispersion independent of the input angle. The spectrometer may be capable of handling about 200 nm bandwidth. The ultra-compact spectrometer may be able to read image data in the visible (400-600 nm) and to read spectral data in the near-infrared (700-900 nm) wavelength range. The surface area of the spectrometer may be about 1 mm2, allowing it to fit on mobile devices.

Optical spectroscopy has been a key characterization technique in a variety of settings, from scientific study to industrial and healthcare applications. A spectrometer can produce spectral lines and may be able to measure their wavelengths and intensities. Spectrometers use a dispersive element, such as a diffraction grating or prism, to achieve a wavelength-dependent angle dispersion, accompanied by focusing optics that focus the incoming light on the detector. These spectrometers are bulky and have low angular tolerances (angular tolerance is the angle at which incident light may enter a spectrometer and spectroscopy can be performed), which limits their use on mobile devices; thus, there exists a need for a compact spectrometer with high angular tolerances.
The above information disclosed in this Background section is only for enhancement of understanding of the background of the disclosure and therefore it may contain information that does not constitute prior art.


A sprinkler stand for holding an oscillating sprinkler in an elevated and generally vertical orientation to provide a desired sprinkler coverage pattern, wherein a sprinkler holder holds a sprinkler, a frame elevates and supports the sprinkler holder, and a base supports the frame. Preferably, the sprinkler holder includes two tracks for engaging base members of a sprinkler, wherein the tracks allow for the repositioning of the sprinkler so as to vary the sprinkler elevation, the height of the sprinkler holder is adjustable by moving the holder along the frame, or by adding a frame extender to the frame, and the sprinkler holder may be rotated, or the frame rotatably or angularly adjusted to achieve a desired sprinkler orientation.

Oscillating water sprinklers are well known and their use constitutes a popular method of watering a lawn or garden. Typically, an oscillating water sprinkler includes a base formed by two generally straight and opposing parallel members that join two generally curved opposing end portions. A perforated spray tube, which receives and projects water, is coupled to and supported by the base. Water may be supplied to the perforated tube by a hose so that the force of the water causes the tube to oscillate and project water in a spray pattern that covers a generally rectangular region around the sprinkler base.
The area that receives the water projected by the sprinkler may be referred to as the sprinkler coverage area. In general, the oscillating sprinkler is positioned horizontally so that both parallel members of the sprinkler base are in contact with the ground. The locus of the sprinkler typically defines the midpoint of the sprinkler coverage area generated when the tube is free to oscillate to its fullest extent. In an alternative mode of sprinkler operation, the perforated tube may be locked in a position that limits the oscillation of the tube so that the spray pattern is directed to a smaller area, for example, only one side of the sprinkler.
The ability of an oscillating sprinkler to adequately deliver water to a desired area is dependent on the volume of water delivered to the sprinkler, the height of vegetation proximate to the sprinkler, and the position and orientation of the sprinkler spray tube relative to the intended watering area. Tall shrubbery, vegetation, or other obstructions in the vicinity of the sprinkler may diminish the sprinkler's efficacy by blocking a portion of the water streams projected from the sprinkler, thereby preventing some areas from receiving an adequate amount of water during the watering session.
Furthermore, because water is delivered to the sprinkler by a hose, which acts as a tether to a water source, the positioning of the sprinkler, and thus the reach of its projected spray, is constrained by water supply location and hose length. In addition, there are some situations in which a sidewalk, patio, driveway, or other surface which does not need to be watered intervenes between the sprinkler and the intended targeted area. In such circumstances it is desirable to project water beyond the intervening area, while at the same time avoiding the waste of resources that results when water is directed to such surfaces. At times it may be desirable to water only a relatively narrow area, such as a narrow lawn area that has been seeded, aerated, fertilized or otherwise cultivated. In those cases, the delivery of water to undesignated areas during the irrigation process wastes resources, increases the time required to adequately water the designated area due to the volume of water diverted, and results in increased monetary costs.
To avoid blockage by vegetation and thereby increase the distance over which the water may be projected from a particular sprinkler location, the oscillating sprinkler may be elevated a vertical distance above the ground. When the sprinkler is elevated, water projected from the sprinkler is more likely to travel over nearby vegetation rather than being obstructed by it. In some watering applications, however, it is desired to not only avoid structural or vegetative obstructions, but also to alter the spray pattern and shape of the corresponding sprinkler coverage area.
For a relatively narrow area extending at a distance from the sprinkler, sprinkler elevation alone is insufficient for producing a sprinkler coverage area that more nearly correlates with the size and shape of the targeted lawn area. By elevating the sprinkler and holding it in a generally vertical position in which the sprinkler spray tube is oriented either perpendicular or at some relative angle to the ground rather than horizontally in parallel with the ground, the spray pattern may be altered to concentrate on the desired swath. The spray coverage may also be modified by locking the oscillating tube in a position which best directs the water to a desired area.
Previous attempts have been made to address the need for an elevated oscillating tube sprinkler by teaching sprinkler stands, wherein a sprinkler is maintained in an elevated position. Although adequate for their intended purposes, none has taught a sprinkler stand that engages and maintains an oscillating sprinkler in a stable vertical orientation in order to produce a beneficial spray pattern and associated sprinkler coverage area for a narrow designated lawn area.
One type of device holds a garden hose whereby water can be directed in a desired direction via a vertical rod to which a hook for supporting an annular sprinkler head or other type of sprinkler heads or nozzles is coupled. Although it may be possible to hang an oscillating sprinkler on such a hook, the device is not adapted for nor well-suited for securely maintaining the twin base members of a typical oscillating sprinkler in a desired orientation. When used with an oscillating sprinkler, such a stand would most likely cause the sprinkler to shake, move, or dislodge in response to the force of the water projected therefrom. Further, such a device, if used in conjunction with an oscillating sprinkler, would lack disadvantageously angular and rotational adjustability of the sprinkler orientation in order to achieve a desired spray pattern.
Another type of stand is a pedestal for supporting an oscillating sprinkler at an elevated height above the ground, wherein the pedestal firmly engages the sprinkler base so as to securely hold the sprinkler in a particular position. However, such stands disadvantageously limit the sprinkler to a horizontal orientation. Thus, although the elevation of the sprinkler, alone, may prove beneficial, such a pedestal does not provide a means for adjusting the height of the sprinkler; nor is adapted for rotative or angular adjustment of the sprinkler orientation in order to achieve a customized spray pattern for a particular irrigation application.
Other types of devices have been described for use with an oscillating sprinkler to produce an optimal spray pattern, specifically pertaining to the size, shape, and arrangement of the nozzles of the spray tube. Nozzle arrangements have been suggested in order to alter the spray pattern of a typical oscillating sprinkler to address the problem of sprayer-induced puddling, wherein an undesirable concentration of water is applied at certain points of the oscillating cycle of the spray tube. While adequate for its intended purpose, such an adaptation to a standard oscillating sprinkler does not provide a means by which the spray pattern and sprinkler coverage area of the sprinkler may be uniquely tailored to conform to a particular application; particularly when is required to irrigate a specific region while avoiding watering undesignated areas.
Therefore, none of known devices overcome the limitations previously identified with oscillating sprinklers positioned horizontally on the ground. Thus, there is a need for a sprinkler stand adapted to securely engage an oscillating tube sprinkler and maintain the sprinkler in a stable, elevated and generally vertical orientation. There is a further need for a sprinkler stand for use with an oscillating sprinkler in which the sprinkler elevation and orientation may be adjusted so as to generate an optimum spray pattern and sprinkler coverage area for an intended application. In particular, there is a need for a sprinkler stand which secures a sprinkler at an orientation selected by the user to irrigate a relatively narrow designated area in a manner that increases the volume of water delivered to the designated area while decreasing the amount of water outside the designated, so that natural resources may be conserved, monetary costs may be reduced, and the time necessary to complete the watering operation may be shortened.

Stand for oscillating wave-type sprinkler


A device for detecting cardiac ischemia is disclosed. The device includes a processor that is configured to distinguish between two different heart beats types such as ventricularly paced beats and supraventricular beats. The processor collects separate reference data for a first one of the beat types indicative of the normal values of a cardiac feature. The processor performs an ischemia test to beats of the first type by first checking whether valid reference data exists for that beat type. If so, the ischemia test is based on this reference data. If no valid reference data exists for the firs beat type, the processor applies an ischemia test that is not based on reference data for the first beat type.

Implantable medical devices (IMD) that can alert patients or third parties to the detection of ischemic events including heart attacks (Myocardial Infarction) can save lives and reduce damage to a patient's heart tissue, improving the post-myocardial-infarction quality of life. Myocardial infarction (MI) occurs when a blood clot blocks the blood supply to a portion of the heart causing the heart tissue to become hypoxic (ischemic) and also experience decreased metabolite removal. Ischemia detection may occur by analysis of the patient's cardiac activity, especially via electrical waveforms sensed by electrodes.
The sino-atrial (SA) node normally serves as the pacemaker for the healthy human heart. Electrical pacing pulses travel through conduction pathways and cause electrical/chemical changes in adjacent myocardium, producing the coordinated activity of various regions which are associated with the beating of the heart and normal blood-flow. When the electrical conduction network of the heart becomes diminished, when there are factors which cause tissue damage, or when there is insufficient blood-flow supplying the heart itself, the timing of the propagating electrical signals will cause the heart to beat in a less efficient manner, to beat abnormally, or to not beat at all. The heart has back-up systems for beating when the SA node experiences failure, such as the atrioventricular node (AV node), which has a natural pacing rate that is slower than the SA node. Although the heart can somewhat compensate for abnormal pacing, providing artificial pacing in order to assist a sick heart deters the risk of further complications which may lead a patient to more quickly experience worsening levels of heart failure.
Most pacemakers are "demand pacemakers" which utilize sensing in order to only deliver pacing when the heartbeat is too slow. This feature allows pacing to not occur continuously and there may be both paced and non-paced heartbeats throughout the day. Pacemakers can also be "rate-responsive" and contain means for determining what the heart rate should be at different moments in time. Not only do they provide pacing when the heart rate drops below a selected minimum, but these can also set the rate of pacing to create a well adjusted heart rate. Rate-responsive pacemakers may rely upon multiple technologies and sensors to determine the appropriate heart rate. An accelerometer may serve as an activity sensor which detects the patient's level and direction of movement so that increased pacing rates may be provided when the patient is active. Additionally, various sensors may serve to measure breathing characteristics, such as rate, so that faster breathing will provide rate-responsive pacing more akin to that seen endogenously in patients with normal cardiac electrical systems. Additional sensors that measure indices such as carbon-dioxide or cardiovascular sounds can also be used to adjust pacing rate.
Pacemakers can have two or more stimulation leads which not only keep the heart rate from dropping too low, but also to maintain improved coordination between different chambers of the heart. For example, the atria and the ventricles can be made to cooperate better by pacing the structures sequentially and at a well chosen latency for a particular heart rate range. In a multiple lead pacemaker, the processor analyzes sensed cardiac data, and derives information that enables the pacemaker to determine if, when, and where to provide pacing to improve synchronization of the different chambers.
One type of multiple lead pacemaker is a "biventricular pacemaker", also known as CRT (cardiac resynchronization therapy) device. CRT devices can pace both the septal and lateral walls of the left ventricle in order to "resynchronize" a heart. A CRT device may utilize a first lead located in the right ventricle to provide septal stimulation while the second is routed through the coronary sinus and anchored to pace the lateral wall of the left ventricle. A third lead, positioned in the right atrium, may also be used to improve ventricular synchrony with the atrial contraction. The timing between the atrial and ventricular contractions, as well as between the septal and lateral walls of the left ventricle can be programmably adjusted to improve cardiac function in individual patients. CRT technology can be implemented within an implantable cardioverter-defibrillator (ICD). Medically dangerous rhythms such as certain arrhythmias can be halted by giving the heart an electric shock delivered using the ICD (e.g., within the heart itself or by stimulation sites in the chest wall) or external devices. Modern programmable pacemakers allow the medical personnel to select the optimum pacing modes for individual patients. The term "pacemaker" shall henceforth mean a system of one or more devices that provides one or more of pacemaker, CRT, cardioversion, and defibrillator capacity.
When therapies, such as electrical pacing of the patient's heart, occur concurrently with ischemia monitoring of the patient, the effects of these therapies both on the heart and on the sensed cardiac data must be managed by monitoring methods so that ischemia can be accurately measured from the sensed cardiac data.
The combination of a pacemaker or ICD with an ischemia detector is described by Fischell et al in U.S. Pat. Nos. 6,112,116, 6,272,379 and 6,609,023. Fischell describes an IMD which can detect a change in the electrical signal from the patient's heart (cardiac electrical signal) that is indicative of a cardiac event, such as an acute ischemia, and then provide a notification of such an event. The IMD can also be a medical device which senses and/or stimulates cardiac, neural, vagal-nerve, or other anatomical target in order to control cardiac activity. Fischell also describes an external alarm system that can provide additional visual, sonic and vibratory alerting signals and may also provide voice/data communication between the IMD and a remote medical monitoring station.

This patent is subject to a terminal disclaimer.

Cardiac event detection based on selective pacing for establishing a paced heart signal parameter baseline


A water vapor vacuum refrigeration chilled water system with a compressor that allows flash cooling refrigeration system to be practical size and weight. The system utilizes only water vapor. Innovative features include a unique plenum condenser system which allows the refrigeration system to be totally enclosed with little or no effect of ambient temperatures on system performances. The plenum type spray condenser does not need fins or tubes as common refrigeration condensers. The compressor allows the large volume of water vapor to be compressed at high pressure ratios. The compressor is much smaller and lighter than state of the art positive or centrifugal type compressor for the required compression requirements. The compressor sections are made with two dissimilar type compressor rotating sections to obtain the required pressure ratios and flows.

This invention relates to the need to improve refrigeration systems which utilize chilled water. Applications for this type of refrigeration include both process cooling and common air conditioning required for homes, commercial buildings, hospitals and manufacturing facilities. Water flash cooling vacuum vapor refrigeration systems do not use CFC (chlorofluorocarbons) refrigerants gases which damage the atmosphere or the dangerous ammonia and propane systems being proposed for larger systems. Air cycle refrigeration used on aircraft is too inefficient for home and commercial refrigeration.
At the time of filing of this patent there is much concern and activity in the refrigeration field as to which refrigerants gases will be used for replacement of the commonly used CFC's gases and CFC-11, CFC-12, in the present units and operating systems. Even the hydrochlorofluorocarbon, HCFC-22 series previously approved, environmentally are now in question. Major U.S. company has ceased manufacture of HCFC-22 equipment. The use of the expensive HCFC-123 and HFC-134A gases used in centrifugal compressor chilled water systems are in question. There are volumes of reports written on this crisis. In all cases none of these newly developed Halocarbon gases give cycle efficiency greater than the previously used CFC's. CFC refrigerants will not be produced after 1996 and manufacture is already severely reduced.
During the summer months the power used in the U.S.A. for refrigeration and air conditioning especially in commercial areas exceeds twenty five percent of the total energy utilized. Lower efficiency refrigeration systems should not be considered for this reason. It is noticeable that most American manufactures are attempting to adapt or fix their present equipment while Japanese have consortiums working to develop new types of refrigeration systems.
This patent is to introduce the proven thermodynamic principle of flashing water cooling vapor refrigeration. Water is undoubtedly the cheapest refrigerant known to man. This innovative system utilizes a unique type of vacuum vapor compressor to make the water vapor vacuum refrigeration systems applicable for air conditioning of homes, commercial establishments, and for industrial process refrigeration. Water vapor vacuum refrigeration at present is not in the state of the art for these applications, but is only used in large petrochemical and industrial applications. Only water or water glycol mixture is used as the refrigerant in the vapor vacuum refrigerant cycle.
The first historical objection to the water vapor vacuum refrigeration system has been the low operational vacuum range. This objection has now been overcome by progress in design, construction, seals and instrumentation. The second historical and most important objection is the large amount of flashed water vapor that the vacuum compressor must handle at the operating vacuum, with the low density gas and the high compression ratios required. The intent of this invention is to provide a new unique design features and a new type of compressor to overcome the objection of the large volume of vapor that must be compressed at the operating vacuum. High Pressure ratios of 4.75 to 5.75 are required for this system.
The only partially adaptable vacuum pump compressors for water vapor vacuum refrigeration units available today are the Roots type; however, they are not practical for small systems because they are slow, very large, heavy and expensive. Also at the required pressure ratio and flow requirements, an operational limit is reached on the Roots units due to mechanical clearances, heat generated and size requirements of the units. Other types positive or centrifugal compressors are too big and expensive.
Water vapor vacuum refrigeration is not new and is sometimes referred to as steam-jet refrigeration. This method utilizes multi-ejectors and are presently used where large volumes of waste steam at pressure normally from 50 PSIA to 100 PSIA, are available. For reference refer to ASHRAE 1983 Equipment Handbook, Chapter 13.1. The steam multi-ejectors are utilized to creative the low vacuum for water surface flashing in large, generally above 50 ton refrigeration capacity for the industrial and petrochemical industries. These units are huge and weigh tons and not for installation at homes, hospitals, small commercial business or industries. The theory of operation, however, is the same; to chill large quantities of water by flashing to temperatures 32.degree. F. to 45.degree. F. for distribution to areas for air conditioning or process cooling as in the present chilled water systems. The state of the art steam-jet system are open systems in that the chilled water is not recirculated. The coefficient of performance is low due to known inefficiencies of the multi-ejectors or steam-jets vacuum pumps.
The water vapor vacuum refrigeration unique system defined in this patent is a closed system with heat recuperation innovations resulting in a very high total overall thermal efficiency. The system is designed with a unique new type vapor compressor that will enable this system to be applicable to homes, hospitals, commercial air conditioning and industrial refrigeration requirements and process cooling. Units may be designed for load capacities as low as 3.5 tons to an approximate limit of 65 tons per unit with dual units of 130 tons of refrigeration capacity possible. Efficiency and coefficient of performance, COP, of the unique system is much higher than the present large and small Freon, CFC system thus saving much energy.

Unique water vapor vacuum refrigeration system


A foam production method includes mixing liquid nitrogen with a foaming material to produce foam. A gas is produced in situ from liquid nitrogen. As the ratio of the volume of the gas produced by gasification of liquid nitrogen to the volume of the liquid nitrogen is relatively high, when a large gas supply flow is needed to generate a large foam flow, a liquid nitrogen storage device of a small volume can be used instead of bulky air supply devices such as high-pressure gas cylinders, air compressors, air compressor sets and the like, reducing the volume of the air supply device. In addition, the liquid nitrogen used in foaming will release nitrogen gas after the foam blast, such that the nitrogen is also able to inhibit combustion on the surface of burning materials, accelerating the extinguishing of the fire.

The existing compressed gas foam extinguishing methods mainly use foam produced by mixing high-pressure gas and foam solution to extinguish fire. Specific foam extinguishing methods mainly include pressure-regulated compressed gas foam extinguishing methods and gas storage foam extinguishing methods. Among those methods, the compressed gas foam extinguishing method usually employs a gas compressor, high-pressure gas pipeline network, or compressed gas cylinder for gas supply. However, the gas compressor and compressed gas cylinder have limited gas capacity, and can't meet the demand for high-flow, high-pressure, and long-time gas supply; a high-pressure gas pipeline network is unavailable at the vast majority of locations. To realize high-flow, high-pressure, and long-time gas supply, multiple compressors or compressed gas cylinders have to be provided (for example, for a foam fire engine with a flow capacity of 150 L/s, the required gas supply flow is at least 1,050 L/s, which has to be supplied by multiple large-size gas compressors), which take up too much space. Usually there is no enough space for multiple compressors or compressed gas cylinders in the tank area or equipment area in oil depots. Therefore, it is difficult to deploy those compressors or compressed gas cylinders in the field.
With respect to gas storage foam extinguishing methods, usually compressed gas is stored in a fire extinguishing agent container. The compressed gas is heavily consumed during high-flow spurting. To ensure high-pressure spurting of the fire extinguishing agent, compressed gas has to be replenished into the fire extinguishing agent container timely. However, in the high-flow spurting state, adequate replenishment of compressed gas can't be ensured merely by means of air compressors and compressed gas cylinders, and thus the requirement for high-pressure spurting can't be met effectively. The pressure in the container drops significantly as the spurting continues, and the foam performance deteriorates gradually, resulting in a compromised fire extinguishing effect. In the case of fire extinguishing against a severe fire disaster, high-flow foams must be produced for fire extinguishing. In such a case, as the flow of the foam solution is increased, the compressed gas supply has to be increased accordingly. However, high-flow and high-pressure compressed gas supply can't be realized with existing gas supply methods. For example, the maximum foam solution flow capacity of existing compressed gas foam fire engines is only 20-30 L/s, and such compressed gas foam fire engines are mainly used for suppression and extinguishing for general scale fire at present, such as building fire or small-scale ground flowing fire, but are inapplicable to fire in large-scale tank fields or large-scale ground flowing fire.
U.S. Pat. No. 5,497,833A discloses a method for improving the performance of a nozzle for guiding water flow onto a target, which comprises: injecting a liquefied gas and a composition for producing foam in effective amounts into water flowing through the nozzle at a position that is upstream enough from the outlet of the nozzle, to allow that the liquefied gas is essentially fully evaporated and solidified before leaving the nozzle. The method utilizes the driving force produced by gasification of the liquefied gas to increase the water flow velocity and increase the jetting range, and thereby improve the fire extinguishing performance. In addition, the disclosure concludes clearly that the fire extinguishing performance of carbon dioxide is better than that of liquid nitrogen.

Foam producing method, fire extinguishing method, and appliance for foam extinguishing

CHINA PETROLEUM & CHEMICAL CORPORATION QINGDAO RESEARCH INSTITUTE OF SAFETY ENGINEERING


Substantially pure conotoxins are provided which inhibit synaptic transmissions at the neuromuscular junctions and which are useful both in vivo and in assays because they specifically target particular receptors, such as the acetyl-choline receptor, and ion channels. The peptides are of such length that they can be made by chemical synthesis. They also may be made using recombinant DNA techniques, and the DNA encoding such conotoxins having pesticidal properties can be incorporated as plant defense genes into plant species of interest.

Mollusks of the genus Conus produce a highly toxic venom which enables them to carry out their unique predatory lifestyle. Prey are immobilized by the venom which is injected by means of a highly specialized venom apparatus, a disposable hollow tooth which functions both in the manner of a harpoon and a hypodermic needle.
Few interactions between organisms are more striking than those between a venomous animal and its eaveaomated victim. Venom may be used as a primary weapon to capture prey or as a defense mechanism. These venoms disrupt essential organ systems in the envenomated animal, and many of these venoms contain molecules directed to receptors and ion channels of neuromuscular systems.
The predatory cone snails (Conus) have developed a unique biological strategy. Their venom contains relatively small peptides that are targeted to various neuromuscular receptors and may be equivalent in their pharmacological diversity to the alkaloids of plants or secondary metabolites of microorganisms. Many of these peptides are among the smallest nucleic acid-encoded translation products having defined conformations, and as such they are somewhat unusual because peptides in this size range normally equilibrate among many conformations for proteins having a fixed conformation are generally much larger.
The cone snails that produce these toxic peptides, which are generally referred to as conotoxins or conotoxin peptides, are a large genus of venomous gastropods comprising approximately 500 species. All cone snail species are predators that inject venom to capture prey, and the spectrum of animals that the genus as a whole can envenomate is broad. A wide variety of hunting strategies are used; however, every Conus species uses fundamentally the same basic pattern of envenomation.
The major paralytic peptides is these fish-hunting cone venoms were the first to be identified and characterized. In C. geographus venom, three classes of disulfide-rich peptides were found: the α-conotoxins (which target and block the nicotinic acetylcholine receptors); the μ-conotoxins (which target and block the skeletal muscle Na+ channels); and the Ω-conotoxins (which target and block the presynaptic neuronal Ca2+ channels). However, there are multiple homologs in each toxin class; for example, at least five different Ω-conotoxins are present in C. geographus venom alone. Considerable variation in sequence is evident, and when different Ω-conotoxin sequences were first compared, only the cysteine residues that are involved in disulfide bonding and one glycine residue were found to be invariant. Another class of conotoxins found in C. geographus venom is that referred to as the conantokins which cause sleep in young mice and hyperactivity in older mice and are targeted to the NMDA receptor. Each cone venom appears to have its own distinctive group or signature of different conotoxin sequences.
Many of these peptides have now become fairly standard research tools in neuroscience. The μ-conotoxins, because of their ability to preferentially block muscle but not ax nal Na+ channels, are convenient tools for immobilizing skeletal muscle without affecting ax nal or synaptic events. The Ω-conotoxins have become standard pharmacological reagents for investigating voltage-sensitive Ca2+ channels and are used to block presynaptic termini and neurotransmitter release. The Ω-conotoxin GVIA from C. geographus venom, which binds to neuronal voltage-sensitive Ca2+ channels, is an example of such. The affinity (Kd) of Ω-conotoxin GVIA for its high-affinity targets is sub-picomolar; it takes more than 7 hours for 50% of the peptide to dissociate. Thus the peptide can be used to block synaptic transmission virtually irreversibly because it inhibits presynaptic Ca2+ channels. However, Ω-conotoxin is highly tissue-specific. In contrast to the standard Ca2+ channel-blocking drugs (e.g. the dihydropyridines, such as nifedipene and nitrendipene, which are widely used for angins and cardiac problems), which can bind Ca2+ channels is smooth, skeletal, and cardiac muscle as well as neuronal tissue, Ω-conotoxins generally bind only to a subset of neuronal Ca2+ channels, primarily of the N subtype. The discrimination ratio for Ω-conotoxin binding to voltage-sensitive Ca2+ channels in neuronal versus nonneuronal tissue (e.g. skeletal or cardiac muscle) is greater than 108 in many cases.
Additional conotoxin peptides having these general properties continue to be sought.

The Salk Institute for Biological Studies


The present invention is directed to a process for the production of optionally cellular, polyurea elastomer moldings by reacting a mixture containing. (I) a polyisocyanate component having an isocyanate content of about 10 to 30% by weight which comprises an isocyanate-terminated prepolymer prepared by reacting a polyisocyanate with a non-fatty, hydroxy polyester having a hydroxyl functionality of 1 to 4 and a molecular weight of about 500 to 4000, provided that if the hydroxy polyester is based on an aliphatic monocarboxylic acid, the aliphatic monocarboxylic acid is a non-fatty monocarboxylic acid containing less than 12 carbon atoms, PA1 (II) a polyether having at least two isocyanate-reactive groups and a molecular weight of 1800 to 12,000 in which at least 50% of the isocyanate-reactive groups are primary and/or secondary amino groups, and PA1 (III) about 5 to 50% by weight, based on the weight of component (II) of a chain extender comprising a sterically hindered aromatic diamine,. the reaction mixture being processed as a one-shot-system by the RIM process at an isocyanate index of about 70 to 130.. The present invention is also directed to these optionally cellular, polyurea elastomer moldings.

1. Field of the Invention
The present invention is directed to a process for the preparation of optionally cellular polyurea elastomer moldings which are not brittle after demold and cooling by using polyisocyanate semi-prepolymers based on hydroxy polyesters.
2. Description of the Prior Art
U.S. Pat. Nos. 4,433,067; 4,444,910; 4,396,729; 4,530,941; and 4,774,263 are all directed to the production of polyurea elastomers by the RIM process. One of the difficulties of these prior art processes is that the molded articles are brittle after demold and cooling, especially molded articles containing reinforcing agents and/or having a high flex modulus. While it is known that the brittleness of the molded article can be reduced by post curing at elevated temperature, this does not reduce the difficulty of getting the brittle part out of the mold without the part breaking or shattering.
U.S. Pat. No. 4,546,114 proposes one solution to brittle parts by heating the mold to temperatures in excess of 110.degree. C. or maintaining the part in the mold for substantially longer periods than normal to reduce brittleness. However, this solution is impractical on a commercial scale since most existing molds do not have the capability for establishing and maintaining the elevated temperatures necessary and, in addition, the extended period of time which the part must remain in the mold reduces the overall production efficiency.
It is also proposed in the prior art in U.S. Pat. No. 4,442,235 that part brittleness of primarily polyurethane elastomers may be reduced by using 1,3,5-triethyl-2,6-diaminobenzene as the chain extender instead of a mixture of 1-methyl-3,5-diethyl-2,4- and/or -2,6-diaminobenzene.
In order to conduct a reaction injection molding (RIM) process, it is necessary to have liquid reactants and one of the most common methods of liquefying diphenyl diisocyanate (MDI) is the incorporation of ether groups by reaction with either low or high molecular weight polyether polyols. In accordance with the present invention it has been discovered that if these ether groups are replaced by ester groups, that the problem with brittleness can be eliminated, without the need for using excessively high mold temperatures.
It is an object of the present invention to overcome the disadvantages of the prior art with regard to part brittleness at demold and to provide high flexural polyurea elastomer moldings which can be processed using existing equipment, which can be removed from the mold without part breakage and which retain all of the advantageous properties of prior art elastomers. These objects may be achieved in accordance with the present invention as set forth hereinafter.
U.S. Pat. No. 4,374,210 is directed to the use of isocyanate prepolymers or semi-prepolymers as the polyisocyanate component for the production of polyurethane elastomers. This patent discloses and exemplifies (note prepolymer I at column 11/Table 1) the use of prepolymers prepared from hydroxy polyesters for the production of polyurethane elastomers, i.e., elastomers prepared from high molecular weight polyols as opposed to the polyurea elastomers of the present invention which are prepared from high molecular weight amine-terminated polyethers. There is no suggestion in this reference that the problem with part brittleness could be overcome by using polyisocyanate prepolymers or semi-prepolymers prepared from polyester polyols.
U.S. Pat. Nos. 4,201,847 and 4,254,228 both describe an internal mold release agent based on the reaction product of an organic polyisocyanate and a fatty acid ester for use primarily in the production of polyurethane elastomers. These references require the acid component of the polyester to contain a fatty acid; whereas, the acid component of the polyester used in accordance with the present invention is based solely on non-fatty acids.

Polyurea elastomers with reduced brittleness


An embodiment of the invention provides a method for the treatment of a substrate made of paper or a substrate containing paper as support material for a semiconductor component. In an embodiment, the substrate surface is contacted with a solution comprising at least one phenol-containing base polymer and/or copolymer and a crosslinker component. A polymer formulation deposits from the solution onto the surface. The solution may further include an acid catalyst. Embodiments include a semiconductor component formed according to the method of the invention.

The introduction of RF-ID systems as a potential replacement for the bar code, which is susceptible to faults and may be used only in direct visual contact with the scanner, or as a security feature on packaging and other goods is deemed to be a forward-looking application for extremely inexpensive electronics. On account of the flexibility and the large variation range of packaging materials, circuits on flexible substrates, which can be produced in large numbers in roll-to-roll methods, are particularly of interest. On account of the enormous price pressure of such applications, silicon-based circuits are typically suitable only for performance-driven special applications, but not for the mass market.
Alternative systems with integrated circuits based on organic field effect transistors (OFET) constitute a possible solution for this mass application sector of inexpensive electronics.
Semiconducting polymers or organic semiconductors offer the potential, on the other hand, that inexpensive printing techniques may be used for their patterning and application. The gate potential for controlling the transistors may be chosen to be smaller, and the thinner the gate dielectric may be fabricated.
For direct integration into the production process of a packaging, the substrate compatibility is of particular interest. If the packaging is composed of paper or similar materials containing cellulose fibers, the polymer electronics should be integrable directly onto this support material. However, paper generally has a very rough surface, so that its use as a substrate makes high requirements of the integration process.
Although the use of paper as a substrate for polymer electronics is proposed in EP 1 073 993 B1, a concrete realization method is not specified. It is also known that paper is suitable as a substrate for the production of electrochromic displays or electrochemical transistors, without production details being known.

Solution and method for the treatment of a substrate, and semiconductor component


An integrated XNOR flip-flop is provided which is faster than conventional XNOR flip-flop combinations. The integrated XNOR flip-flop is faster and uses less area than conventional XNOR flip-flop combinations. The integrated circuit has few gates along the critical path and takes advantage of the set up times inherent in the flip-flop. Accordingly, the integrated XNOR flip-flop is able to perform the same function in an expedient manner. In one illustrative embodiment, a plurality of the integrated XNOR flip-flops are used to compare a tag of a cache memory with an address to determine whether the desired address is available in the cache.

1. Field of the Invention
The present invention relates generally to static comparator circuits and more particularly to an integrated exclusive-nor gate and flip-flop.
2. Description of the Relevant Art
Exclusive-or (XOR) gates are often used in electronic circuits to compare the logic levels of input signals. The output of an exclusive-or gate is asserted if one, but not both, of the inputs to the exclusive-or gate are asserted. If both inputs to the exclusive-or gate are asserted or both inputs are deasserted, the output of the exclusive-or gate is deasserted. An exclusive-nor (XNOR) gate is similar to an exclusive-or gate with the output inverted. Accordingly, the output of an exclusive-nor gate is asserted if both inputs are asserted or both inputs are deasserted. An exclusive-or or an exclusive-nor gate may be used to determine whether the logic levels of two inputs are the same.
It is often desirable to perform a static comparison of two inputs. Static logic circuits are often more desirable than dynamic logic circuits. Static logic circuits are more robust with respect to noise than dynamic circuits. Additionally, in certain cases, static circuits consume less power than dynamic circuits (power consumption is pattern and implementation dependent). Static circuits are also faster in some cases, especially if the desired evaluation phase coincides with the precharge phase of a dynamic circuit.
Turning now to FIG. 1, one embodiment of a static comparator is shown. FIG. 1 illustrates a one-bit static comparator using an exclusive-nor (XNOR) gate. FIG. 1 includes flip-flop 102, flip-flop 104, and exclusive-nor gate 106. Exclusive-nor 106 includes inverters 108, 110 and 116, and transmission gates 112 and 114.
A first input of flip-flop 102 is coupled to input A. A first input of flip-flop 104 is coupled to input B. The clock inputs of flip-flops 102 and 104 are coupled to a clock signal (CLK). The outputs of flip-flops 102 and 104 are coupled to inputs of exclusive-nor gate 106. The output of exclusive-nor gate 106 is coupled to an output Z.
On a predefined edge of the clock signal flip-flops 102 and 104 latch the current state of input signals A and B respectively. A short time after the predetermined edge of the clock signal, the logic levels of inputs A and B are available at the outputs of flip-flops 102 and 104 and at the inputs of exclusive-nor gate 106. After a short delay, output Z of exclusive-nor gate 106 will be asserted if the inputs A and B are the same logic state. Alternatively, output Z will be deasserted if inputs A and B are different logic states. Because inputs A and B are captured by flip-flops 102 and 104, the circuits that drive A and B may transition after the predetermined edge of the clock without affecting the output Z.
As noted above, output Z of exclusive-nor gate 106 is asserted when either both inputs are asserted or both inputs are deasserted. Input B controls transmission gates 112 and 114. If input B is asserted, then transmission gate 114 logically couples input A to output Z. The output of inverter 108 is the inversion of input A and the output of inverter 116, which is output Z, is the same state as input signal A. Accordingly, when input B is asserted, output Z is asserted if input signal A is asserted and output Z is deasserted if input signal A is deasserted.
If input signal B is deasserted, then output signal Z is the inverse of input signal A. If input signal A is asserted, output signal Z is deasserted. Transmission gate 112 logically couples input A to the input of inverter 116 when input B is deasserted.
Although FIG. 1 illustrates a single bit comparator, a plurality of single bit comparators may be combined to compare multiple bits. In this embodiment, each pair of bits of the input signals are compared using a comparator similar to the one illustrated in FIG. 1. The outputs of each single-bit comparator may be input to an AND gate. If each pair of bits are the same logic level, then all the outputs of the comparators will be asserted. Accordingly, the output of the AND gate coupled to the comparators will also be asserted indicating that the multiple bit inputs are the same.
Turning now to FIG. 2, one embodiment of a flip-flop is shown. Flip-flop 102 includes inverters 202, 204, 210, 212, 216, 218 and 220, NAND gate 206, NOR gate 208, and transmission gate 214. In one embodiment, transmission gate 214 logically couples the output of inverter 210 to the input of inverter 220 when the output of NOR gate 208 is asserted. NOR gate 208 is asserted when both the clock input signal and the output of NAND gate 206 are deasserted. If the enable (ENB) input signal is deasserted, NAND gate 206 is asserted which prevents NOR gate 208 from enabling transmission gate 214. Thus, if the enable input signal is deasserted, transmission gate 214 is disabled. Alternatively, if the enable input signal (ENB) is asserted, the output of NAND gate 206 is deasserted when the output of inverter 204 is asserted. The output of inverter 204 is a delayed version of the clock input signal. Accordingly, when the enable input is asserted, NOR gate 208 will enable transmission gate 214 while the clock signal is deasserted and a delayed version of the clock signal is asserted. This set of conditions exists for a brief period of time on a transition of the clock signal from the asserted to the deasserted state. This brief period of time is approximately equal to the propagation delay of inverters 202 and 204 and NAND gate 206. During this brief period of time, transmission gate 214 is enabled and couples the inversion of the input to the inputs of inverters 218 and 220.
Inverters 216 and 218 comprise a keeper circuit. The keeper circuit is designed to maintain the logic level of the output of transmission gate 214 after transmission gate 214 has been disabled. When transmission gate 214 is enabled, it drives the input of inverter 218. The current drive of transmission gate 214 is sufficient to overcome the current output of inverter 216. Accordingly, if the output of transmission gate 214 is a different state than the output of inverter 216, the output of inverter 218 will be the inversion of the output of transmission gate 214, not inverter 216. The output of inverter 218 drives the input inverter 216 such that the output of inverter 216 is the same state as the output of inverter 214. After transmission gate 214 is disabled, inverters 216 and 218 maintain the logic level output by transmission gate 214 prior to being disabled. Inverter 220 inverts the state maintained by inverters 216 and 218 and buffers the output Q.
Flip-flop 104 may implement a similar or identical circuit to flip-flop 104.
Unfortunately, conventional comparison circuits such as those shown in FIGS. 1 and 2 are too slow for some applications. What is desired is a faster static comparator circuit.

Integrated XNOR flip-flop for cache tag comparison


A method and system for estimating DC offset and removing the excess DC offset from samples used by an overlap-and-add operation at the receiver of OFDM symbols in UWB communication. The DC offset for each sample within the overlap-and-add interval may be estimated using a sliding window, of the size required for an FFT, operation over past samples. The DC offset may be estimated for a sample within the overlap-and-add interval and updated for the succeeding samples. A size of the overlap-and-add interval may be fixed or may be allowed to vary according to switching characteristics of an analog RF stage preceding the overlap-and-add operation.

The present invention relates generally to ultra-wide band (UWB) communication and orthogonal frequency division multiplexed (OFDM) signals in UWB communication, and more particularly to symbol interference correction for received symbols.
Ultrawideband (UWB) communication systems communicate information spread over a large bandwidth, a bandwidth generally shared with other users. Generally, UWB systems may use OFDM signals. An OFDM carrier signal is the sum of a number of orthogonal subcarriers. Baseband data on each subcarrier is independently modulated. Some type of quadrature amplitude modulation (QAM) or phase-shift keying (PSK) may be used as the modulation scheme. The composite baseband signal is typically used to modulate a main RF carrier. OFDM modulation and demodulation may be implemented using digital filter banks generally using a Fast Fourier Transform (FFT) scheme.
OFDM symbol structures and frequency hopping patterns are disclosed in Multiband OFDM Physical Layer Specification, Release 1.0, Jan. 14, 2005 ("MBOA Standard") which is incorporated by reference herein.
The presence of a multipath channel may present difficulties for data communication. In a multipath environment, a transmitted signal may reflect off several objects. As a result, multiple delayed versions of the transmitted signal may arrive at a receiver. The multiple versions of the signal may cause the received signal to be distorted. As a result, each received subcarrier may experience a complex gain, including an amplitude and a phase distortion, due to channel effects. An OFDM symbol transmitted through a multipath wireless channel may encounter both an intersymbol interference and an intrasymbol interference problem. Intersymbol interference is generally the result of interference between successive OFDM symbols. The intrasymbol interference occurs in multicarrier systems, and may be the result of interference amongst the subcarriers of a single OFDM symbol.
A guard interval may be used to address the effects of intersymbol interference as well as to provide transmitters and receivers time to frequency hop in frequency hopping systems. A first, or last, few samples of a symbol are set as a guard interval. The guard interval generally will not contain any useful information and may be discarded at the receiver. The guard interval, however, may not eliminate interference with a symbol.
A cyclic prefix may be included in each symbol to reduce interference effects. A cyclic prefix generally includes a replica of the last samples of a symbol and as such contains redundant information that may be discarded at the receiver. The cyclic prefix generally has the effect of the symbol appearing periodic to a Fast Fourier Transform (FFT) unit, and transforms a convolution of the symbol samples with the channel effects into a multiplication of the two that may be more readily undone in the frequency domain. However, using a cyclic prefix generates a ripple in the power spectral density of the transmitted signal which increases power use. Using a null prefix instead of a cyclic prefix does not generate a ripple in the spectrum, and therefore, using a null prefix may permit an effective higher transmission power for UWB transmissions. The use of a null prefix, however, may result in difficulties in accounting, for example, for multipath interference.

Overlap-and-add with DC-offset correction


The present invention may be used for discharging a fire retardant material. A container element may be connected to a pressurized gas source controllable to pressurize the container element and to flow a gas and fire retardant material mixture through a discharge conduit. A discharge device may be connected at an inlet to the discharge conduit. The discharge device may have an inlet duct attached to an inlet end of an expansion section. The expansion section may be connected to an inlet end of an outlet duct having an outlet nozzle. A diffuser may be disposed in the inlet duct and an upstream portion and may be attached in the upstream portion. The diffuser may have a nose element attached by a diffuser shaft to a base element with a rotor element having multiple vanes rotatably attached to the diffuser shaft intermediate the nose and base elements.

This invention relates to apparatus for retarding or suppressing fires. The new fire retardant discharge apparatus may have a retardant and air container and mixer connected to a discharge device for dispensing retardant through the air to be deposited on a fire.
Transport of fire retardant materials to fight large fires, such as forest fires, may usually is done with the use of aircraft that may be fixed wing aircraft or helicopters. The fire retardant that may be di-ammonium phosphate, PHOS CHEK or other generally solid retardants may be dropped from the air at a fire location with a widely varying degree of effectiveness. The fire retardant drop may be affected by weather conditions as well as pilot capabilities.
Water or other fluid retardants may also be transported and dropped by aircraft. The traditional fire engine may be used to pump water to be sprayed on a fire using a hose. Water may be a relatively heavy, bulky product to carry as compared to generally dry powder type fire retardant materials.


One aspect of the invention relates to a method of cleaning high density capacitors. According to the method, the capacitors are cleaned with a plasma that includes fluorine-containing radicals. The plasma removes a small layer from the capacitors, including their sidewalls, and thereby removes surface contaminants. The method is effective even when the capacitors include hard-to-etch dielectric materials, such as tantalum and hafnium oxides. In a preferred embodiment, the plasma clean is combined with a solvent clean.

Although integrated circuit devices have become progressively more compact in recent years, there continues to be a demand for still more compact devices. Higher density device elements that lend themselves to formation into compact devices are continuously sought. One device element for which higher density is sought is a capacitor.
To make integrated circuits with high density capacitors, there is a need for new semiconductor device manufacturing processes. High density capacitors require high-k dielectric materials such as tantalum pentoxide. Making capacitors with materials such as tantalum pentoxide presents process integration challenges. Such materials are incompatible with many other materials and are difficult to etch. Moreover, smaller, thinner capacitors are more sensitive to non-uniformities and contamination than their thicker counterparts. The foregoing challenges illustrate a long felt need for improved processes for making semiconductor devices having high density capacitors.


An upright bypass type vacuum base section pulls from a suction chamber surrounding the bag.

Traditional upright vacuums using a bypass suction with a disposable fiber bag draw suction from under the bag. Thus, as dirt accumulates in the bottom of the bag, the motor has to pull suction through the accumulated dirt. A loss of suction at the inlet head results. As the bag fills, the cleaning efficiency at the inlet head decreases.
Some bypass type vacuum cleaners draw suction from one side of the bag instead of the bottom. Examples of such vacuums include Sebo models X1 and X4 and Riccar Radiance and Simplicity Synergy (D527,5055, D515,4345). These vacuum cleaners should maintain their cleaning efficiency as the bag fills.
What is needed in the art is a bypass vacuum system that pulls suction from at least two sides of the bag. Also needed in the art is an exhaust air sanitizing system to return sanitized air to the user's environment.
The present invention provides suction from three sides of the bag. A side door also has an accordion shaped back segment to improve suction. Upon removal of the bag, the bag is closed to prevent dust from escaping into the user's environment.
The sanitizing of the exhaust air system has a UV light and radiant catalytic ionization unit, trademark of Ecoquest, Greeneville, Tenn. It can also include a silver nitrate antimicrobial liner and/or impregnation in the bag. It can also include a silver nitrate impregnated and/or lined exhaust air filter.


Embodiments of the present invention are method and apparatus for simultaneously measuring the length and refractive error of an eye, preferably in a non-contact mode. In particular, an embodiment of the present invention is an apparatus which measures length and refractive error of an eye which includes: (a) a source of short coherence radiation which couples radiation into a Michelson interferometer, the arms of the Michelson interferometer having a predetermined optical pathlength difference; (b) an injector which couples radiation output from the interferometer into the eye; and (c) a relay system which couples radiation output from the eye to a spectrometer; wherein the spectrometer measures displacement of radiation to measure the refractive error and the spectrometer measures density of fringes to measure the length.

Intraocular lenses are used to replace a lens in a patient's eye in the case of cataracts. In such instances, it is important to measure the length and refractive error of the patient's eye in order to provide an appropriate replacement for the lens. In many of these cases, however, it is not possible to use standard optical refractometry because the fundus is not visible through the turbid cataract eye lens. Standard optical refractometry suffers from the additional drawback that it does not measure the length of the patient's eye.
Ultrasound biometry is a method that is used to measure the length of the patient's eye. In performing ultrasound biometry, an ultrasound transducer is placed on the cornea of the patient's eye. Next, an ultrasound pulse is emitted by the transducer and is reflected back from the fundus of the eye. As is well known, the time of flight of the pulse depends on the length of, and the index of refraction of the ultrasound pulse in, the patient's eye. Using this information, the length of the patient's eye can be determined. However, there is a drawback in using ultrasound biometry. In particular, in order to receive an echo which is strong enough to be measured with a suitable signal-to-noise ratio, the ultrasound transducer has to be brought into contact with the patient's eye and a special contact jelly has to be used. This is a problem in that the method is invasive and, in many countries, only a medical doctor is permitted to use this method.
An alternative method used to measure the length of the patient's eye makes use of short coherence interferometry and is free from the above-described drawback. This alternative method is described in an article entitled "Optical Coherence Tomography" by A. Fercher, Journal of Biomedical Optics, Vol. 1, No.2, April, 1996, pp. 157-173 (the "Fercher article"). However, this alternative method is limited in that it only measures the length, and not the refractive error, of the patient's eye.
In light of the above, there is a need for a method and apparatus for simultaneously measuring the length and refractive error of an eye, preferably in a non-contact mode.

Method and apparatus for simultaneously measuring the length and refractive error of an eye


A method and apparatus for providing remote control of content rendered by a set top box is described including transmitting a state request message by a user to the set top box via a server, receiving a state reply message by the user from the set top box via the server, determining by the user if the user needs to control the set top box responsive to information in the state reply message and transmitting a remote control command to the set top box via the server. Also described are a method and apparatus including recording information of events by the set top box, receiving a state request message via a server, generating a state reply message including the recorded information, transmitting the state reply message via the server, receiving a remote control command via the server and performing an action specified by the remote control command.

In multicast and broadcast applications, data are transmitted from a server to multiple receivers over wired and/or wireless networks. A multicast system as used herein is a system in which a server transmits the same data to multiple receivers simultaneously, where the receivers form a subset of all the receivers up to and including all of the receivers. A broadcast system is a system in which a server transmits the same data to all of the receivers simultaneously. That is, a multicast system by definition can include a broadcast system. The present invention is not limited to a conventional TV but may also be used to control content (programs) rendered on a computing device via the Internet.
Set top boxes could provide rich content and popular/fashionable services to home users because they have capabilities to interface with some device within the internet. For some digital video broadcast (DVB) programs, there is a parental control descriptor in the event information table (EIT) to suggest an appropriate age level for viewing the content (program). This could prevent young children from seeing some adult programs (content). A similar function has been provided in some conditional access (CA) systems. Concerning the healthy growth of children and protecting their eyesight, some parents want a way to know the playing time of their set top box and to control its capability when they are out of the home.

Parental control of content viewing by children using a remote smart phone