An earth boring drill bit for large diameter shafts has an improved cutter arrangement. The drill bit has a cutter support member with a number of cutters mounted to it for disintegrating the earth formation face. At least one inner cutter is mounted near the center for cutting the center area. A number of gage cutters are mounted at the periphery to cut the gage area of the shaft. A number of intermediate cutters are spaced between the inner and gage cutters. Each intermediate cutter overlaps one-half of its width with an adjacent intermediate cutter.

1. Field of the Invention
This invention relates in general to earth boring drill bits and in particular to a large diameter shaft bit having an improved cutter arrangement.
2. Description of the Prior Art
Drill bits for large diameter shafts normally have a cutter support plate that is connected to a string of drill pipe for rotation. A number of cutter assemblies are secured to the cutter support plate to disintegrate the earth as the cutter support plate is rotated. The drilling may be downward, or upward by pulling the bit through a pilot hole, as shown in U.S. Pat. No. 3,805,901.
Normally the cutters are arranged to cut separate paths, although two or more cutters may be located in the same path for more effective earth disintegration. If two or more cutters are located in the same path, they must have different insert spacing patterns to avoid tracking. "Tracking" is a condition which results when a cutter tooth engages a previously made depression in a borehole bottom or face. As a result, a crest of rock may be generated on the face, which may lead to disadvantages such as erosion of the cutter shell or premature tooth disintegration. The different insert patterns require additional inventory and costs.
Another disadvantage of prior art drill bits is that the bit bodies may not be used both for tooth cutters and for discs. A disc cutter has a sharp circumferential ridge, rather than individual teeth. The best disc cutters utilize only a single ridge, since it has been found that double ridge disc cutters wear faster than single ridge cutters. However, the bearing and seal requirements normally require a fairly wide mounting bracket for tooth cutters. Mounting a single disc in a wide mounting bracket would place the disc too far from adjacent discs for the desired spacing.

Shaft drill bit with overlapping cutter arrangement


Antenna nodes are controlled to maintain a respective radio cell, each cell having one and the same physical cell identity. The antenna nodes are further controlled to maintain the respective radio cell in a single direction substantially along a path such that each wireless communication device, during movement in a movement direction along the path, can connect either to consecutive antenna nodes towards which the wireless communication device is moving or connect to consecutive antenna nodes away from which the wireless communication device is moving.

Wireless communication systems, i.e. systems that provide communication services to wireless communication devices such as mobile phones, smartphones etc. (often denoted by UE that is short for user equipment), have evolved during the last decade into systems that must utilize the radio spectrum in the most efficient manner possible. A reason for this is the ever increasing demand for high speed data communication capabilities in terms of, e.g., bitrate and to provide these capabilities at any given time, at any geographical location and also in scenarios where the wireless communication device is moving at a high speed, e.g., on board a high speed train.
To meet this demand, within the third generation partnership project, 3GPP, work is being done regarding possible enhancements to radio resource management, RRM, performance in high speed train environments. The justification is that there are railways such as Japan Tohoku Shinkansen (running at 320 km/h), German ICE (330 km/h), AGV (talo (400 km/h), and Shanghai Maglev (430 km/h) which vehicles travel at greater than 300 km/h and where there is demand for using mobile services. In a motivation contribution to 3GPP RAN#66, RP-141849, four scenarios of interest to wireless communication network operators are disclosed. In a number of these scenarios, there is a dedicated network to provide railway coverage of the cellular system; either as a standalone network, or used in conjunction with a public network which is not specifically designed to provide high speed train coverage. The four scenarios in RP-141849 can be summarized as follows:
Scenario 1: A dedicated network is deployed along the railways (such as antenna nodes in the form of remote radio head, RRH, deployments). Separate carriers are utilized for dedicated and public networks. By sharing the same Cell identity among multiple RRHs, handover success rate can be increased to some extent.
Scenario 2: Separate carriers are utilized for high speed scenario. One carrier with good coverage serves as a primary cell, PCell, for mobility management. One carrier at high frequency may provide the good data transmission. Carrier aggregation, CA, or dual connectivity, DC, could be applied.
Scenario 3: A public network is deployed along the railways and repeaters are installed in train carriages. With repeaters, the signal quality can be improved although the penetration loss is large.
Scenario 4: A dedicated network is deployed along the railways and repeaters are installed in carriages.
Current standard specifications have partly taken UE speeds up to 300 km/h into account, but only in the context of data demodulation, not for cell detection. With increased deployment of high speed train lines, increased number of UE users, and increased usage of bandwidth per user, dominating network operators are requesting improved UE performance and support for speeds exceeding 300 km/h. Future high speed trains are expected to travel at speeds above 500 km/h, e.g. the Superconducting Magnetic Levitation train (SCMaglev) to be deployed in Japan, where train sets have already in April 2015 reached more than 600 km/h in speed tests.
For the development of the fifth generation of mobile telecommunication technology (5G), the International Telecommunication Union (ITU) has defined a set of requirements, IMT-2020, which includes the support of UE speeds of above 500 km/h with respect to mobility and data communication.
Apart from the relatively shortened time for detecting suitable neighbor cells for handover or cell reselection, high speed movement of the UE may also lead to significant Doppler shifts of the received radio signals. Such a Doppler shift forces the UE to increase its demodulation frequency when moving towards a cell (i.e. moving towards an antenna that defines a radio lobe of the cell), and decrease demodulation frequency when moving away from a cell, in order to maintain an acceptable receiver performance.
The Doppler shift can be expressed as:
      Δ                          f    =      f    (                                        1            -                          v              c                                            1            +                          v              c                                          -      1        )  where c is the speed of light and v is the relative velocity of the UE towards the transmitting antenna. Referring to FIG. 1, an UE 101 is on a high speed train 103 on a railway track 104, connected to and moving away from cell A2 105 and quickly needs to detect cell B1 107 towards which the UE 101 is moving with a velocity νUE 109 of the train. According to current standard an antenna 111, 113 of a cell site can be as close as 2 m from the railway track 104, mainly motivated by that the wireless communication network would be integrated with the high-speed railway infrastructure. With an angle α between railway track 104 and a direction 106 to a cell antenna 113 and a UE velocity νUE, the relative velocity ν towards the transmitting antenna giving rise to Doppler shift is ν=νUE cos α.The magnitude of the Doppler shift depends on the relative velocity of the UE 101 towards the transmitting antenna in a cell. Consequently, with transceivers located close to a path along which an UE is moving, i.e., a small angle between the trajectory of the UE and the line between the UE and the transmitting antenna, a substantial part of the UE velocity will transfer into a Doppler shift. Moreover there will be an abrupt change of sign of the Doppler shift when the UE passes the transmitting antenna and the smaller the angle, the more abrupt is the change from positive to negative Doppler shift.
Each radio propagation path may have its own Doppler shift, depending on how the radio waves travel between the transmitting antenna and the UE. In case of line-of-sight there is one dominant path, whereas in e.g. urban areas there is generally scatter (reflections) due to buildings to which the UE has a relative velocity, giving rise to multiple paths for the signal to propagate to the UE, each with a different Doppler shift. Since the received signal (in general) is the superposition of those paths, it gives rise to Doppler spread which degrades radio receiver performance by smearing out the signal in the frequency domain hence causing inter-carrier interference.
High-speed railway track sections are generally using dedicated platforms often elevated above the landscape or city beneath. Hence, there are few objects that can cause a significant Doppler spread; with cell sites located along the track line-of-sight will be dominating at least between the cell site and the train. Moreover, in built-up areas as well as when a train is approaching or passing stations the speed is generally restricted of concern for public safety and disturbing noise, and as a consequence the Doppler shift becomes small.
With regard to handover of a UE from a source cell to a target cell or, in scenarios where carrier aggregation is used, handover to a new primary cell, PCell, configuration of a new secondary cell, SCell, and configuration and activation of a new primary secondary cell, PSCell, is usually based on measurement reports from the UE, where the UE has been configured by the network node to send measurement reports periodically, at particular events, or a combination thereof. Such measurement reports typically contain physical cell identity, reference signal strength, RSRP, and reference signal quality, RSRQ, of the detected cells. Handovers can also be blind (i.e. no measurements performed on target carrier and/or cell) based on the network node having knowledge about coverage on other carriers and location of the UE. An example of this can be found in U.S. Pat. No. 8,892,103 entitled "Methods and nodes supporting cell change".
The latency at a handover to a known (measured) PCell counted from reception of the handover command at the UE antenna until the UE carries out contention-free random access towards the target cell, can be up to 65 ms comprising 15 ms RRC procedure delay, 20 ms preparation time for the UE, and up to 30 ms latency for next physical random access channel, PRACH, occasion. One of the purposes with random access is to configure the UE with an appropriate timing advance value such that uplink transmissions by the UE are aligned with the subframe timing when received by the network node. Each random access attempt typically takes 20 ms hence in case the UE has to repeat the random access due to not getting response from the network node the time will be prolonged, but as a general figure one can assume 85 ms in total until the UE can resume communication in the target cell provided that the first attempt of random access is successful.
In the UE the preparation time is needed, e.g., for stopping processing and tearing down data structures and data memory associated with the source cell to release processing, memory and radio resources so they are available for the configuration to be used in the target cell. The reconfiguration may in general require re-partitioning of the data memories due to other bandwidth used in target cell, loading of new program code to support other transmission modes or radio access technology than in source cell.
However, there remain a number of challenges in relation to high-speed train scenarios in prior art. For example:                The UE experiences high Doppler shifts when passing an antenna node at a cell site, particularly when the site is close to the railway as in scenarios 1, 2 and 4 in RP-141849 summarized above. Such shifts also occur when the UE is handed over from one cell to another if the UE is moving in opposite directions to the cells. The abrupt shifts means that the UE will have to retune its radio before it can receive and transmit again, which is further prolonging a handover.        A UE that is between two antenna nodes, e.g. remote radio heads, in Scenarios 1, 2 and 4 in RP-141849 will receive the same signal from at least two directions, with opposite Doppler shifts. This gives rise to a Doppler spread also in the line-of-sight case, causing inter-carrier interference and degrades the receiver performance when both towers are received with about the same strength.        The abrupt change of sign for the Doppler shifts causes the frequency offset (discrepancy between UE demodulation frequency and the perceived carrier frequency) to be so large that it falls outside the capture range of the estimators. The UE risks tuning towards the wrong target with severely impacted performance and/or radio link failure as result.        Existing assumptions on network deployments for high-speed train scenarios assumes inter-cell distance of 300 m to 1000 m, which means that the UE changes or passes an antenna node at, e.g., a cell tower every 150 m to 500 m. This means that the UE will have to retune its receiver every 1.1 to 3.6 seconds when moving at a speed of 500 km/h. Each handover-related and/or Doppler-related interruption will have a significant impact on both system and UE throughputs.        Downlink, DL, and/or uplink, UL, Coordinated multi-point, CoMP, operation techniques can be deployed in both homogeneous and heterogeneous networks (see e.g. 3GPP TR 36.819 v11.1.0). But with high Doppler shifts and abrupt change of sign for the Doppler shifts it is impossible to use DL/UL CoMP techniques to enhance base station and/or UE performance as it requires good frequency (equal or less than 300 Hz) and time tracking between Quasi-collocated base stations from multiple points.

This patent is subject to a terminal disclaimer.

Radio cell arrangement in high speed scenario


An optical mount for an optical element which has an optical surface. The mount includes a first plate and a second plate which holds the optical element. The second plate has a spherical bearing surface that cooperates with the first plate so that the optical element pivots about a point on the optical surface. The mount has a single first adjustment device to pivot the optical element about one axis and a single second adjustment device to pivot the element about a second perpendicular axis.

1. Field of the Invention
The present invention relates to an optical mount.
2. Background Information
Mechanical mounts are commonly used to secure and vary the position of an optical element such as a mirror. The mount may be part of an optical system such as a laser or an interferometer. The system may be tuned or calibrated by varying the incident angle of the light reflected from the mirror. A conventional optical mount typically has a number of adjustment screws that can be manipulated to tilt the mirror and vary the angle of incidence.
There have been marketed gimbal optical mounts that can tilt the reflecting mirror and change the incident angle without spatially shifting the point at which the light is reflected from the mirror. This can be accomplished by reflecting light from the pivot points of the gimbal mount which are coincident with the mirror face. Gimbal mounts allow a scientist to vary the incident angle without introducing a phase shift in the reflected light.
Conventional gimbal optical mounts typically contain two concentric rings. The innermost ring holds the optical element and can rotate relative to an outer ring. The outer ring can rotate relative to an outer stationary housing about an axis that is perpendicular to the axis of rotation of the inner ring. Ring type gimbal mounts can be relatively expensive to produce.
U.S. Pat. No. 4,088,396 issued Edelstein and U.S. Pat. No. 3,357,268 issued to Richter disclose optical gimbal mounts which each have a first plate and a second plate. The first plate is typically mounted to a stationary surface such as a table. The second plate holds the optical element and has a spherical bearing surface. The spherical bearing surface cooperates with a spherical seat of the first plate to allow the second plate and optical element to pivot about a point. Unfortunately, the pivot point is located away from the optical surface of the optical element so that pivoting the element may introduce a phase shift in the reflected light.
There have been published articles which discuss the use of gimbal optical mounts that have kinematic type interfaces which pivot the optical element about a point on the optical surface. These mounts have three or four adjustment screws that are manipulated to pivot the optical element. Accurately pivoting the optical element typically requires manipulating two screws the same amount. Manipulating two screws can be both cumbersome and time consuming. For example, a gimbal mount with three or four screws requires the simultaneous manipulation of at least two screws to pivot the optical element about an axis. It would be desirable to provide an opto-mechanical mount that can tilt an optical element without introducing a spatial phase shift and which can pivot the element about an axis by manipulating only one screw.


The folding chair with a movable shade includes a back support frame and a flexible back support, a seat support frame and a flexible seat and a cross frame member pivotally mounted between the back frame and the seat support frame to provide an angular seating position for the user. A shade member includes a shade frame and a shade element. The shade member is pivotally mounted to a top portion of the back support frame. A control member coupled either to the shade frame or the back support frame establishes the angular shade position of the shade with respect to the back support and the seat support.

Folding beach chairs are well known. Typical beach chairs include a back support frame upon which is mounted a flexible back support, a seat support frame and a mounted flexible seat as well as a cross frame member that is pivotally mounted between the back support frame and the seat support frame which establishes the angular seating position between the back support and the seat support. Additionally, these folding beach chairs typically are hinged such that the back support can be positioned adjacent the seat support and the user can carry the collapsed beach chair.
As used herein, the term "beach chair" is not meant to limit the folding chair invention to chairs solely employed or utilized on a beach. As is commonly known, these types of folding chairs are used on patios, at sporting events, and in parks and recreational areas, in addition to being utilized on the beach.


A fan control system for cooling apparatus such as cooling tower in which water and air are brought into contact together. According to this system, the running speed of the fan is continuously and proportionally changed responsive to the temperature of the cooling water or the external atmospheric conditions, to substantially control the cooling capacity of the cooling apparatus. The control system consists of a main fan motor, an electronic adjustment circuit and a power transmission means consisting of a variable pitch diameter belt speed changing means and a constant pitch belt reduction device, whereby the speed changing ratio of the belt speed chaning means is continuously and proportionally changed depending upon the control signals from the adjustment circuit. Further, the adjustment circuit may have a soft-start control circuit.

This invention relates to an improved apparatus for forcibly bringing the air and water into contact together, and more specificially to an improved cooling apparatus such as cooling tower or evaporative condenser.
In general, when water sprayed into the air and fell onto a water vessel is pumped and is sprayed again repetitively, the temperature of water gradually approaches the wet bulb temperature of the air. Widely known cooling apparatus utilizing this principle may be represented by cooling towers or evaporative condensers. As is well known, according to such apparatus, the air stream is forcedly created in the tower by a fan in order to increase the contacting amount between water and air; hence the cooling capacity of such apparatus varies in proportion to the difference in enthalpy between the air and the air of a temperature equal to the temperature of the water. The enthalpy of the air is approximately represented by the wet bulb temperature. Substantially, therefore, it is proper to say that the cooling ability or capacity is dependent upon the difference between the wet bulb temperature of the outdoor air and the temperature of the cooling water at the inlet port. Consequently, the change in the outdoor air wet bulb temperature or in the temperature of the cooling water naturally causes the cooling capacity of the cooling tower to be varied.
According to most of the conventional cooling apparatus of this type, however, the water feeding rate L (kg/hr) and the air feeding rate G (kg/hr) have been maintained constant. it is a generally accepted idea that a refrigerator operates with a reduced load when the outdoor atmospheric or air temperature is low and when the outdoor air wet bulb temperature is low. In such a case, the cooling tower having increased cooling ability should be operated at reduced cooling capacity. In spite of this fact, however, the conventional cooling towers have not been controlled to follow such changes in temperatures.
In particular, the cooling towers are often irrationally operated during the seasons of spring and fall; the temperature of the cooling water is often excessively lowered. In winter, the temperature of the cooling water may further decrease, making it difficult to control the refrigerating capacity of the refrigerator, or giving rise to the occurrence of a refrigerant backing phenomenon or increase in the consumption of the electric power, causing the apparatus to become inoperative or presenting damage to the compresser finally.
In order to overcome such disadvantages, U.S. Pat. No. 2,287,297 discloses fan blades of a fan which can be varied. The fan having such variable blades, however, is very expensive, and permits the blowing amount of the air to be varied only within a narrow range, and is therefore not practicable. Another system to cope with the above-mentioned defects is to control the amount of the water supplied to the tower by providing a cross or three-way valve and a by-pass conduit between the cooling water inlet port and the cooling water outlet port of the cooling tower. This system, as is well known, has now been extensively used. However, since the amount of the cooling water is made variable, it is difficult to maintain desired cooling performance and to keep the cooling water at an uniform dispersion in the tower. A further method to cope with the above-mentioned defects consists of automatically controlling the start and stop of the fan and a fan motor. According to this method, however, the electric motor is very frequently started and stopped especially in the winter season, thus giving a conflicting nature to the recent tendency toward saving the energy. Therefore, it has been urged to provide a fan which suits for the cooling apparatus such as cooling tower, which can be cheaply manufactured, and of which the running speed can be continuously and proportionally changed.

Fan control system for cooling apparatus


A pest resistant molybdenum disilicide composition is provided for use in high temperature structural applications. The composition includes molybdenum disilicide and silicon nitride and can be used to prepare improved reinforced composites.

Several ambitious programs have been initiated to develop the next generation of advanced aircraft for aerospace transportation. It is the goal of programs such as the Integrated High Performance Turbine Engine Technology (IHPTET) program, the National Aerospace Plane (NASP), and the High Speed Civil Transport (HSCT) to develop turbopropulsion capabilities far beyond those achieved using today's technology. To reach these goals structural materials are needed that can withstand extreme temperatures and hostile environmental conditions.
Advanced high temperature materials are the key to successfully developing the next generation aerospace propulsion and power systems. Advanced materials will enhance the performance of these systems by allowing higher speeds, expanded flight ranges, and increased payload capabilities. The materials must be light weight and able to reliably withstand the stresses associated with flight at speeds in excess of Mach 2.5. Due to increased temperature capabilities and relatively low densities, composite materials are widely recognized as the advanced materials needed for future systems.
A principle obstacle to the development of such systems, is the lack of high temperature composite materials having a combination of high specific strength, fracture toughness, high and low temperature oxidation resistance and high temperature creep resistance. To date, only nickel aluminide and molybdenum disilicide appear to have the potential for such high temperature applications as the HSCT exhaust nozzle because most other intermetallic systems exhibit detrimental high temperature oxidation behavior. Of these, molybdenum disilicide appears to be the most favorable candidate because it is a silica former and can withstand temperatures up to 1773K, roughly 473K higher than nickel aluminide which is an alumina former.
The intermetallic compound molybdenum disilicide (MoSi.sub.2) has long been known to have excellent high temperature oxidation resistance. It has the additional advantages of low cost, a high melting point of 2300K, a relatively low density of 6.5 gm/cc (versus 8 gm/cc for current engine materials), it is non-toxic and environmentally benign, and can be easily machined using standard metallurgical practices. All of these advantageous properties make molybdenum disilicide an extremely attractive structural material for high temperature aerospace applications.
Unfortunately, the successful use of MoSi.sub.2 has been hindered due to its brittle nature at low temperatures, relatively high coefficient of thermal expansion, average creep resistance at high temperatures and, most importantly, its accelerated oxidation at temperatures between about 673 and 773K. The accelerated oxidation of MoSi.sub.2 at intermediate temperatures causes the material to disintegrate into powder, a phenomenon known as pesting. Thus, while MoSi.sub.2 will perform exceptionally well at higher temperatures, it is unsuitable for structural applications such as high temperature engine components that must be repeatedly heated up through intermediate temperatures. Upon the repeated thermal cycling of such engines the MoSi.sub.2 components would simply pest and fall apart.
Pesting is a general term describing the catastrophic oxidation of intermetallic materials at intermediate temperatures. The accelerated oxidation leads to the disintegration or `pesting` of the material and the component falls apart. For MoSi.sub.2 the temperature at which pesting is most pronounced is approximately 773K. It has been observed that at 773K, bulk (i.e., non-composite) MoSi.sub.2, as well as composites of MoSi.sub.2 with alumina and aluminum nitride, all suffer total disintegration within 100 hours. It was concluded that the pesting of MoSi.sub.2 was little affected by the density of materials and the presence of foreign additives. The pested samples yielded powdery products consisting of MoO.sub.3 whiskers, SiO.sub.2 clusters, and residual MoSi.sub.2. The MoO.sub.3 whiskers exhibited protruding characteristics and were concentrated at grain boundaries and cracks. The pesting phenomenon in MoSi.sub.2 has been concluded to be the result of the formation of voluminous molybdenum oxides in microcracks. While not wanting to be bound by theory, the accelerated oxidation apparently involves the simultaneous formation of MoO.sub.3 and SiO.sub.2 in amounts essentially determined by the Mo and Si concentrations in the intermetallic.
In the last five years, an extensive amount of work has been carried out in efforts to overcome the problems associated with the use of MoSi.sub.2 as a high temperature structural material. While solid solution alloying, dispersion strengthening and fiber reinforcing have had limited success, these approaches still have not made MoSi.sub.2 a viable structural material.
Alloying with tungsten, tungsten disilicide or rhenium has improved high temperature creep strength, but not resolved the problems of pesting or matrix cracking. While substantial improvements in high temperature strength have been achieved by dispersing aluminum oxide in the matrix, again the pesting problem has not been resolved.
Known techniques of fiber reinforcement have been unsuccessful at curing this problem because MoSi.sub.2 has a relatively high coefficient of thermal expansion (CTE) as compared to most potential reinforcing materials, such as silicon carbide (SIC) fibers. The CTE mismatch between the fiber and the matrix material results in matrix cracking during fabrication and severe matrix cracking during thermal cycling, which of course leads to component failure. Candidate fibers include high strength ceramic fibers such as silicon carbide, single crystal alumina, and ductile, high strength molybdenum and tungsten alloy fibers. Ductile niobium fibers have been shown to improve the low temperature strength and toughness but a severe reaction occurring between the Nb fiber and MoSi.sub.2 matrix material limits its use and the high temperature characteristics were not improved at all. While the addition of silicon carbide (SIC) whiskers has yielded improvements in room temperature toughness, pesting and CTE mismatch are still a problem.
In spite of its high CTE, refractory metal fiber reinforcement of MoSi.sub.2 matrices was shown to increase both creep strength and toughness. The addition of about 40 vol % of low thermal expansion phase such as SiC in the form of whiskers and particles was shown to lower the thermal expansion of MoSi.sub.2 base matrices and reduce matrix cracking of refractory fiber reinforced composites. However, there was a severe reaction between the refractory fibers and the matrix. Matrix cracking was observed during consolidation with a silicon carbide fiber reinforced composite even with the matrix containing up to 40 vol % silicon carbide to modify the thermal expansion. An SCS-6 (silicon carbide)/MoSi.sub.2 -40 vol % SiC composite survived only 5 thermal cycles at 1573K and was completely destroyed within 100 hours of exposure to air at 773K.
Sapphire fiber reinforced composites showed no evidence of matrix cracking due to the good thermal expansion match between MoSi.sub.2 and sapphire, but because sapphire bonds strongly with MoSi.sub.2 it does not provide any improvement in the toughness.
While some form of reinforcement with continuous fibers having high strength and high aspect ratio appears necessary for the strength and damage tolerance required for high temperature aerospace applications, a solution to the pesting and matrix cracking problems has still not been found.
Improvements in fabrication of MoSi.sub.2 have led to materials having less porosity and correspondingly less susceptibility to pest attack. However, because of increased surface areas and complexities of fabrication from incorporating reinforcement phases in MoSi.sub.2 based composites, pesting of the composite material is still a major concern and a principle obstacle that must be overcome before the next generation aerospace goals can be achieved. In short, one of the most promising materials for such applications cannot be used unless a solution to the forgoing problems is found.

Pest resistant MoSi.sub.2 materials and method of making

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


A pattern recognizing apparatus includes an image pick-up device for picking up an image of a component for teaching and an image of a component to be recognized, and a feature value calculating device for calculating a feature value based on the image picked up by the image pick-up device. Also provided is a processing control device for outputting a teaching signal indicating a processing rule to be applied to the components for teaching, a histogram forming device for receiving the teaching signal and the feature value calculated based on the image of the component to be recognized and forming a histogram of the feature value of the rule based on the teaching signal and the received feature value, and a membership function forming device for forming a membership function which includes a noise eliminating device for performing linear interpolation to valleys of the histogram, and a threshold processing device for changing the histogram to a membership function through a threshold process. A calculating device is provided for finding a membership value based on the feature value calculated by the image of the component to be recognized based on the membership function formed by the membership function forming device, and calculating an acceptance of fit of the rule applied to the component to be recognized. A selecting device is provided for selecting a rule having the maximum acceptance of fit to decide a pattern of the component to be recognized. The apparatus calculates the acceptance of fit of a pattern on the basis of the membership value of the shape feature value, so that the membership function can be formed efficiently.

The present invention generally relates to an image recognition apparatus used, for example, in factories and plants, and more particularly, to a pattern recognizing apparatus adapted to classify objects such as components through pattern matching of shape feature values of images.
A conventional pattern recognizing apparatus performs pattern recognition as follows. The average value of a shape feature value of reference patterns, such as an area, peripheral length or secondary moment of each reference pattern, and a respective standard deviation are obtained in advance. Then, the shape feature value of an image of the pattern of an object to be recognized is calculated and compared with that of the reference pattern, whereby the object is recognized.
The conventional pattern recognizing apparatus is based on the assumption that each kind of shape feature value varies in a normal distribution. However, in actuality, the variation of the shape feature value does not always assume a normal distribution. Therefore, the conventional apparatus often is unable to recognize certain patterns or often erroneously recognizes certain patterns.
Meanwhile, the present applicant has previously proposed a pattern recognizing apparatus utilizing fuzzy inference. This pattern recognizing apparatus will be described with reference to FIG. 5.
In FIG. 5, reference numeral 21 denotes a calculating means for calculating shape feature values of input images; 22 denotes a pattern deciding means; 23a-23n denote calculating means for calculating an acceptance of fit of respective rules thereof; and 24 denotes a rule selecting means for selecting a rule having a maximum acceptance of fit.
Initially, the calculating means 21 calculates shape feature values of an input image. More specifically, it calculates the shape feature value of each of suitably set image sections of the input image. The shape feature value of each section is input to the pattern deciding means 22, where a decision is made as to whether the input image is of an object to be recognized.
A plurality of production rules (IF-THEN rules) are set corresponding respectively to patterns of objects to be recognized in the pattern deciding means 22. The overall acceptance of fit of each production rule relative to the input shape feature values is obtained by fuzzy inference using membership functions provided in the condition part of each production rule for each input shape feature value. A rule having the maximum acceptance of fit is decided as corresponding to the subject pattern identified in the action part of the production rule.
In other words, the acceptance of fit of each membership function of each rule is obtained in the calculating means 23a-23n based on the output value of each membership function relative to the input shape feature values, and the overall acceptance of fit of a rule is found by summing the acceptance of fit of the membership functions of the rule.
Alternately, the minimum acceptance of fit of the membership functions of a rule may be designated as the overall acceptance of fit of the rule, or the acceptance of fit of the membership functions of a rule may be multiplied together to obtain the overall acceptance of fit of the rule.
Subsequently, the rule selecting means 24 selects the rule having the maximum overall acceptance of fit from among those obtained in the calculating means 23a-23n. The subject rule, i.e., the subject pattern is decided in the above-described manner.
In the above pattern recognizing apparatus, it is necessary to form the most suitable membership functions in order to realize optimum pattern recognition. However, forming of the membership functions based on the intuition and experience of a system designer is overly troublesome and inconvenient.

Matsushita Electric Industrial Co., Ltd.


A container incorporating post-consumer recycled ("PCR") plastic and a method of making that type of container. The container utilizes a layer of polypropylene or EVOH or a film of fluorinated polyethylene toward the interior from the recycled plastic to prevent contaminants from the latter entering the container's contents. When utilizing EVOH, the container usually has an additional layer of polyethylene or polypropylene covering the EVOH to prevent its deterioration by moisture. Making the container involves first composing a resin including the recycled plastic. Forming the various layers listed above produces a container that includes recycled plastic and a barrier to limit the migration of contaminants f from the recycled material to the container's contents. This permits the use of the resulting containers for food. For a fluorinated polyethylene film, fluorination can occur either during or after the container's formation.

Plastic containers, for an extensive period of time, have found widespread use in society for holding a vast array of goods. In fact, such containers have become so omnipresent that their disposal now poses a substantial problem. Society no longer wishes to place the used containers into the very limited landfill left to it.
Accordingly, recent years have witnessed a substantial effort to recycle plastic containers. This would accomplish several desirable results. First, it will help save the limited resources of our planet for future generations. Furthermore, recycling will have the obvious effect of conserving the landfill that remains available.
However, much plastic finds use in containers that hold food items. Most desirably, recycling must employ previously used plastic in new food containers. In fact, various legislative bodies are considering the requirement that a certain portion, generally around 25 percent, of all containers, including specifically those intended for food, must consist of recycled plastic.
The problem with utilizing recycled plastic in food containers results from the fact that these containers have previously held all types of materials. Many of these materials, for one reason or another, constitute contaminants should they enter food items above a negligible concentration.
The essential problem arises, of course, from the fact that contaminants found in recycled plastic, because of their previous use, could leach out of the new containers and into the food. A brief acknowledgment of the wide variety of uses that plastic containers find shows the magnitude of the concern. Thus, plastic holds everything from food itself including milk to chemicals such as herbicides and insecticides that could prove toxic to humans and other animals.
Consumers may exacerbate the problem. After emptying the contents of a plastic container, they may reuse it to hold chemicals of an entirely different, and perhaps more ominous nature, than the originally held ingredients. These may include everything from used motor oil to all types of poisons. These containers too, after their initial and subsequent uses by the consumer, may enter the recycling stream. Any use of the plastic from these containers in recycling must provide absolute assurance that whatever such containers may have held will pose no danger to food consumed by individuals.
The United States Food and Drug Administration (FDA) has determined that a contaminant on a level below 0.5 parts per billion in ingested food presents substantially no risk of harm to humans. Thus, any use of recycled plastic in containers must provide assurance that it will not cause the exceeding of that level of undesired foreign substances in a person's diet. In particular, the FDA requires a demonstration, under adverse conditions, of protection against four classes of chemicals; these classes include volatile and nonvolatile, polar and nonpolar organic compounds, as well as a heavy-metal salt and a polymer-specific chemical. Thus, the intended manner of use of post-consumer recycled ("PCR") plastic must show that it will not introduce more than the indicated amount of contaminant into food.
One particular method of employing recycled resin involves placing a barrier layer on the inside of the previously used plastic. Such a barrier must prevent the passage of contaminants into a container's interior holding a food-like substance, generally an ethyl alcohol solution. One test for establishing this barrier capacity involves placing the container made of or with the proposed barrier and containing the alcohol solution in essentially pure contaminant. Alternatively, the test may involve placing the contaminant on the exterior of a container with the barrier material.
The need for a barrier, however, only exists when the contaminant level within the recycled plastic exceeds certain maximum levels. Below those levels, as suggested in the FDA Points to Consider for the Use of Recycled Plastics in Food Packaging: Chemistry Considerations (May, 1992), an insufficient amount of contaminant could possibly leach into the container's contents to create a health risk. The calculation assumes that all of a contaminant in the PCR resin will enter the container's food. In the case of polyolefins, that contaminant level currently stands at 48 parts per billion (ppb.) for a container having a PCR layer 0.020 inch thick. A thicker layer will have more contaminant and cause the permissible level to proportionately decline. Several layers with PCR introduce additive quantities of the contaminant. This has special significance since much PCR resin has a majority of polyethylene. Polyethylene terepthalate ("PET"), by comparison, may have a residue of 215 ppb. Between those two sit polystyrene at 180 ppb. and polyvinyl chloride at 90 ppb. Decreasing the PCR layer thickness increases the allowable contaminant level. Only the thickness of the layers within the PCR are considered in this determination. Diluting the PCR with virgin resin proportionately increases the permissible contaminant level in the unmixed PCR.
The current recycling process does appear to reduce the concentration of some contaminants in previously used resin. However, the present treatment of recycled materials does not seem to currently offer the hope of reducing the residue level of all contaminant types to below these limits.
Accordingly, the search continues for barriers that will permit the use, and perhaps the required use, of recycled plastic for food containers. Yet, the barrier should not prohibitively increase the cost of the resulting containers.


A machine tool, particularly a lathe, has three longitudinally extending, laterally spaced guides mounted on a frame to extend substantially parallel to one another. Two carriages are slidably mounted on the guides for movement therealong, the two carriages being movable in parallel directions. Each of the carriages is mounted on a respective one of the outer guides and on the central guide. The central guide is provided with guide faces arranged to provide complete guidance of each carriage in the two directions orthogonal to the longitudinal extent of the guide, that it, both laterally and vertically.

The present invention relates to machine tools, and particularly to lathes.
A lathe is known in which three longitudinally extending, laterally spaced guides are mounted on a frame to extend substantially parallel to one another. Two carriages are slidably mounted on the guides for movement therealong, the two carriages being movable in parallel directions. Each of the carriages is mounted on a respective one of the outer guides and on the central guide.
In this known lathe, the central guide and the two outer guides are formed by broad hardened steel bars mounted on an under-frame which is a casting. Each of the two carriages is supported on one of the outer guides, and both carriages are supported conjointly on the central guide.
Each carriage is guided laterally by the engagement of a lower carriage segment between the respective outer guide and the central guide, this carriage segment resting without play, on the facing longitudinal sides of the said guides, which sides are spaced from one another. As a result, it is not possible to shift the carriage on the guides transversely to the carriage adjustment direction and transversely to the guide members.
Each carriage is guided vertically by way of counterstrips, located on the underside of the carriage, which rest on lower support faces on the corresponding guides. This prevents the carriages lifting off the guides.
Accordingly, both the guides which guide each carriage are involved in the lateral guiding and in the vertical guiding of the carriage, that is all three guides are involved in the guiding of both carriages. This makes it necessary that the three guides are all precisely parallel to one another in order to ensure that the carriages can move parallel to one another. This can only be achieved at considerable manufacturing expense.
It is an object of the present invention to provide a machine tool, such as a lathe, having the features described at the outset, in which for lateral guiding of the carriages precise parallel alignment of the guides relative to one another is no longer necessary.


In a wireless telecommunication system for transmitting a plurality of streams from a base transmission station comprising a plurality of antennas to a mobile station comprising a plurality of antennas, the base transmission station respectively transmits, by way of a plurality of the antennas, each stream obtained by dividing data to be transmitted. The mobile station respectively receives each stream by utilizing the plurality of antennas. A measurement unit respectively measures a reception quality or received power from each antenna relating to a stream. A change over unit carries out a handover for each stream according to a measurement result by the measurement unit.

1. Field of the Invention
The present invention relates to an MIMO (multiple input multiple output) transmission technology for transmitting a plurality of streams by way of a plurality of antennas.
2. Description of the Related Art
In a wireless telecommunication system, mobile terminals (i.e., terminals) are enabled to continue a telecommunication if a received power, et cetera, is reduced by selectively changing a connected base station over to an optimal one based on a received power, a reception quality, et cetera, from surrounding base stations (e.g., refer to patent documents 1, 2, 3 and 4; and a non-patent document 1). An example of a wireless telecommunication system is the recently propagated W-CDMA (Wideband Code Division Multiple Access) system.
FIG. 1 exemplifies a configuration of a telecommunication system adopting the W-CDMA system. The terminal (i.e., a mobile station, MS) receives signals from a plurality of base transmission stations (BTS) BTSa, BTSb, BTSc through BTSn. The mobile station selects a base transmission station with the largest received power as the optimal base transmission station for the telecommunication from among the plurality thereof to connect to a network via the selected base transmission station. If a received power from a nearby base transmission station (i.e., adjacent base transmission station) becomes larger than that from the connected base transmission station as a result of the mobile station moving for example, a handover, i.e., changing the connected base transmission station to the nearby one, is carried out for a continued telecommunication. A handover is also carried out according to the telecommunication environment in the case of transmitting and receiving a plurality of data streams simultaneously between a base transmission station and mobile station by utilizing the MIMO technique. The following description is of a handover processing utilizing the MIMO technique in a wireless telecommunication system adopting the HSDPA (high speed downlink packet access) as one standard specification of W-CDMA.
FIG. 2 shows an overview of a handover processing according to the conventional technique; illustrating a handover processing in a downlink transmission under the HSDPA system 100, that is, in a data transmission from the base transmission stations to a mobile station. In the example of FIG. 2, a 2 by 2 antenna configuration is structured between a base transmission station and a mobile station.
Prior to a handover, a mobile station 102 receives a data stream via a base transmission station 103A as shown by FIG. 2(a). As the received power from a base transmission station 103B becomes larger than that of the base transmission station 103A at the mobile station 102, a handover processing changes the base transmission station 103A to the base transmission station 103B with a larger received power, as the base transmission station for transmitting a data stream over, as shown by FIG. 2(b). In this event, the two data streams transmitted from the base transmission station 103A are simultaneously changed over. The handover processing results in the mobile station 102 receiving two data streams via the base transmission station 103B.
FIGS. 3, 4A and 4B exemplify respective configurations of a receiving apparatus and a transmission apparatus according to the conventional technique. Here, the mobile station 102 is a receiving apparatus, while the base transmission station 103 is the transmission apparatus. And in the examples of FIGS. 3, 4A and 4B, the mobile station 102 and the base transmission station 103 comprise, respectively, three antennas, for transmission and reception, thereby configured to transmit and receive three data streams simultaneously. Incidentally, antennas (i.e., Tx1 through Tx3; and Rx1 through Rx3), utilized for transmitting the data stream from the base transmission station 103 to the mobile station 102, are delineated separately from antennas (i.e., Tx0 and Rx0) for transmitting a signal from the mobile station 102 to the base transmission station 103, for ease of viewing of FIGS. 3, 4A and 4B. But each antenna is used both for transmitting and receiving signals in the actual structure. That is, the antenna Tx0 comprised by the mobile station 102 is achieved by a discretionary one or a plurality of the antennas Rx1 through Rx3, and likewise the antenna Rx0 comprised by the base transmission station 103 is achieved by a discretionary one or a plurality of the antennas Tx1 through Tx3. Note that this also applies to those drawings herein where the transmission and reception antennas are separately delineated in the following descriptions.
The conventional mobile station 102 as shown by FIG. 3 comprises three antennas Rx1, Rx2 and Rx3, and the corresponding receiver units 111A, 111B and 111C. Received power measurement units 112A, 112B and 112C measure the received power from each base transmission station 103 at the respective receiver units 111A, 111B and 111C. A handover judgment unit 113 calculates the total received power, i.e., a sum of the received power at each base transmission station based on the measurement result at each received power measurement unit 112 and judges whether a handover is to be carried out or not.
In the conventional base transmission station 103 as shown by FIG. 4A, the antenna Rx0 receives handover control information transmitted from the antenna Tx0 of the mobile station 102. The received information is provided to a handover control signal extraction unit 131 by way of the receiver unit. The handover control signal is transmitted to an upper level control station, that is, a radio network controller (RNC) in the HSDPA system 100.
FIG. 4B shows a configuration, relating to a handover processing, of an RNC as the upper level station of a base transmission station 103. As a handover signal is transmitted from the base transmission station 103 to the RNC, a handover control unit thereof determines a timing for carrying out a handover. A handover control unit 132 of the base transmission station 103 carries out a handover by receiving a notification from the RNC.
FIG. 5 shows a process procedure of a handover in the conventional system. The first step is to measure a received power from each base transmission station (S101), compare the total received power from the surrounding base transmission station of the mobile station 102 (S102), judge whether or not a handover is to be carried out based on the comparison result and, if it is judged that a handover is to be carried out, determine which base transmission station is to be handed over to (S103).
FIG. 6 is a flow chart showing a definite measurement process of a received power as a part of the conventional handover processing. In the example shown by FIG. 6, the n-number of base transmission stations exist in the surrounding area of the mobile station, and each terminal station is equipped by the m-number of antennas respectively. Meanwhile, it is defined that a received power of a signal from the base transmission station of a base transmission station number j is Pj and that the power received by the antenna Ax is Prx.
In the measurement process of a received power, initialize the antenna number, the base transmission station number and the received power from each base transmission station (S111), increment the base transmission station number j and the antenna number i, by one, respectively (S112 and S113) and add the received power Prx when receiving a signal from each base transmission station via each antenna Ai and acquire the sum of the received power (S114, S115 and S116). The sum of received powers is acquired for the n-number of base transmission stations, respectively (S117).
In the conventional handover processing, the necessity of a handover is judged based on the sum of the received powers and when the base transmission stations are changed over from the current base transmission station to a target base transmission station for transmitting a data stream, the data stream is transmitted via a different base transmission station pre- and post- the handover, as shown by FIGS. 5 and 6.
FIG. 7 illustrates data transmission pre- and post- a handover according to the conventional technique. The handover is defined as the mobile station 102 moving from under the base transmission station BTS1 to the BTSh. As shown by FIG. 7(a), the base transmission station BTS1 transmits data prior to a handover and, when the upper level control station, i.e., an RNC, carries out a handover at a prescribed timing, it cuts off the path between the RNC and base transmission station BTS, and instead establishes a path between the RNC and another base transmission station BTSh. As shown by FIG. 7(b), the data is then transmitted via the post-handover base transmission station BTSh, leaving data accumulated in the base transmission station BTS1 prior to the handover un-transmitted.
If the accumulated data in the base transmission station BTS, as shown by FIG. 7 is left un-transmitted, the mobile station 102 is unable to receive all the data. In order to prevent such a loss of data from occurring, a data transfer or a retransmission has been carried out in the conventional technique.
FIGS. 8 through 11 describe the processing for preventing a data loss at a handover occurrence of the conventional system. In FIGS. 8 through 11, definitions for designations are as follows: a current base transmission station (i.e., the station which hands a terminal over): BTSa, a target base transmission station (i.e., the station which a terminal is handed over to) BTSb, the data delivered to the BTSa, and BTSb are data A and data B, respectively.
FIG. 8 describes a state of a buffer at each base transmission station prior to a handover. A radio network controller RNC, i.e., the upper level control station of a base transmission station, transmits data to the mobile station via the connected BTSa. The data A is accumulated in the buffer of the BTSa.
FIG. 9 describes a state of the buffer at each base transmission station immediately after carrying out a handover in the case of retransmitting data after the handover. After carrying out a handover, the mobile station 102 connects itself to a network via the BTSb. The buffer of the BTSb accumulates the data B after carrying out a handover. Meanwhile, the data A which has been delivered to the BTSa before carrying out the handover ends up remaining in the buffer thereof.
FIG. 10 describes a data retransmission processing by the upper level control station. As shown by FIG. 9, the data A is the data transmitted to the current base transmission station BTSa prior to the handover and accumulated in the buffer. The RNC, i.e., the upper level control station, receiving a request from a mobile station 102, retransmits the data A accumulated in the BTSa to the BTSb, that is, the target base transmission station, while the data A in the BTSa is discarded. In the BTSb, a signal exchange between the mobile station 102 and RNC is conducted for a retransmission control prior to a retransmission processing of the data A, followed by retransmitting the data A. An exchange of a retransmission control signal and the actual retransmission processing are time consuming.
FIG. 11 describes a state of a buffer at each base transmission station immediately after carrying out a handover in the case of transferring data after the handover. This method transfers, to the BTSb via the RNC, data A accumulated in a buffer of the BTSa, as a result of a handover. Similarly, for such a transfer, an exchange of a control signal and actual transfer processing are time consuming as with the data retransmission processing shown by FIG. 10.
As described by referring to FIGS. 8 through 11, since a plurality of data streams simultaneously transmitted are changed over at the same time in the conventional technique, a data loss occurs in a mobile station 102 unless the data accumulated in the buffer of a current base transmission station is retransmitted or transferred to the mobile station 102. There is a problem of a handover process being time consuming as much as the processing of retransmitting or transferring the data taking time, hence resulting in a decreased transmission speed.
Meanwhile, in a system for wirelessly and simultaneously transmitting mutually independent data streams respectively from a plurality of transmission systems by using the same frequency, as a MIMO related technique, there is a technique for wirelessly transmitting a transmission data stream simultaneously by using the same frequency, respectively, from a plurality of transmission systems, following changing over from a mutually independent plurality of data streams to a plurality of sub-streams, if a received power of a mobile station (or a reception quality) assumes a prescribed threshold value or less. According to such a technique, a MIMO transmission is carried out if a mobile station exists in the neighborhood of a base transmission station with a relatively large received power, while a diversity transmission is performed if a mobile station exists in an area of a relatively low received power. In the neighborhood of the two areas, a changeover between the MIMO transmission and the diversity transmission is conducted.
[Patent document 1] laid-open Japanese patent application publication No. 2004-72624
[Patent document 2] laid-open Japanese patent application publication No. 2003-338781
[Patent document 3] laid-open Japanese patent application publication No. 2004-229088
[Patent document 4] laid-open Japanese patent application publication No. 2005-509565
[Non-patent document 1] 3GPP Specification: 25.211 Re1-5, Version 5.7.0, [online], Aug. 2, 2005, 3GPP, searched on Aug. 3, 2005, Internet <URL: http://www.3gpp.org/ftp/Specs/html-info/25211.htm>

Wireless telecommunication system, transmitter and receiver


An air purifier has an air flow path with a dielectric body interposed across the path. The dielectric body may be made of, for example, quartz or alumina fibers or silica granules or sponge so that it is porous to air and transmissive to ultraviolet (xe2x80x9cUVxe2x80x9d) light. A source of ultraviolet light emits UV1 and UV2 light into the airflow path upstream of the dielectric body and at least UV2 light into the dielectric body itself. The UV light forms ozone. The ozone, as well as water vapor in the air, naturally attaches to the dielectric body which concentrates these materials in the dielectric body. The UV light irradiating the ozone and water in the dielectric body causes the formation of highly reactive hydroxyl radicals which assist in sterilizing the incoming air.

This invention relates to an air purifier and to a method of air purification.
It is known that ultraviolet (xe2x80x9cUVxe2x80x9d) light sterilizes DNA so that biological material (such as viruses, bacteria, molds, yeasts, and pollens) exposed to UV light either dies or cannot reproduce. This property of UV light has been utilized to sterilize air in a building by simply placing UV lamps in the building""s air ducts. One drawback with this approach is that biological material may not be exposed to UV light for a sufficient time to be sterilized. To address this drawback, it is known to utilize a porous air filter and mount a UV light for reciprocating movement across a face of the filter. In operation, a fan draws air through the filter resulting in biological material becoming trapped in the filter. The irradiation of the filter with the reciprocating UV light acts to kill this trapped biological material. However some biological material, namely viruses, readily pass through porous filters and would not, therefore, be sterilized with the combination of a porous filter in conjunction with a UV lamp. Furthermore, UV light degrades a porous filter requiring frequent replacement of same.
In our U.S. Pat. No. 5,656,242 issued Aug. 12, 1997, we describe several air purifiers which sterilise air with UV radiation. In one embodiment air is drawn through a filter and a perforated metal plate into a primary radiation cavity containing a UV light. The filter traps biological material which is exposed to a low UV dose via the perforations in the metal plate. In another embodiment, air is drawn along a U-shaped path defined by a filter transmissive to UV2 and blocking UV1. UV1 and UV2 radiation generated by a lamp in the first leg of the U-shaped path forms sterilising ozone (O3) in this leg; the UV2 which passes through the filter into the second leg of the U-shaped path breaks down this ozone. Water misters in this second leg result in the disassociated ozone forming hydroxyl radicals (OH) which further sterilise the air. Thus, the air is sterilised directly by the UV radiation and also indirectly by the UV radiation creating ozone and hydroxyl radicals. While this embodiment results in an effective purifier, water misters may not be readily available and increase maintenance needs of a system.
Therefore, there remains a need for an effective air purifier.
An air purifier has an air flow path with a dielectric body interposed across the path. The dielectric body is fabricated so as to be porous to air and transmissive to ultraviolet (xe2x80x9cUVxe2x80x9d) light. A source of UV light emits UV light into the dielectric body and, optionally, also into the air flow path upstream of the dielectric body. The UV light may form ozone. Ozone, as well as water vapour in the air, naturally attaches to the dielectric body which concentrates these materials in the dielectric body. The UV light irradiating the ozone and water in the dielectric body causes the formation of highly reactive hydroxyl radicals which assist in sterilising the incoming air.
Accordingly, in one aspect, there is provided an air purifier comprising: an air flow path; a dielectric body which is porous to air and transmissive to ultraviolet light interposed across said air flow path; and a source of ultraviolet light for emitting ultraviolet light such that ultraviolet light is present in said dielectric body.
According to another aspect of the invention, there is provided an air purifier comprising: an air flow path; a dielectric body interposed across said air flow path, said dielectric body being porous to air and fabricated of at least one of silica, silicon dioxide, aluminum oxide, magnesium fluoride, calcium fluoride, barium fluoride, strontium fluoride, lithium fluoride, quartz and sapphire; and a source of ultraviolet light for emitting ultraviolet (xe2x80x9cUVxe2x80x9d) light such that ultraviolet light is present in said dielectric body
According to a further aspect of the present invention, there is provided a method of air purification comprising: passing contaminated air through a dielectric body which is porous to air and transmissive of ultraviolet (xe2x80x9cUVxe2x80x9d) radiation; and UV irradiating said dielectric body.


This invention provides a progesterone receptor agonist of formula 1 having the structure

Intracellular receptors (IR) form a class of structurally related gene regulators known as xe2x80x9cligand dependent transcription factorsxe2x80x9d (R. M. Evans, Science, 240, 889, 1988). The steroid receptor family is a subset of the IR family, including progesterone receptor (PR), estrogen receptor (ER), androgen receptor (AR), glucocorticoid receptor (GR), and mineralocorticoid receptor (MR).
The natural hormone, or ligand, for the PR is the steroid progesterone, but synthetic compounds, such as medroxyprogesterone acetate or levonorgestrel, have been made which also serve as ligands. Once a ligand is present in the fluid surrounding a cell, it passes through the membrane via passive diffusion, and binds to the IR to create a receptor/ligand complex. This complex binds to specific gene promoters present in the cell""s DNA. Once bound to the DNA the complex modulates the production of mRNA and protein encoded by that gene.
A compound that binds to an IR and mimics the action of the natural hormone is termed an agonist, whilst a compound that inhibits the effect of the hormone is an antagonist.
PR agonists (natural and synthetic) are known to play an important role in the health of women. PR agonists are used in birth control formulations, typically in the presence of an ER agonist, alternatively they may be used in conjunction with a PR antagonist. ER agonists are used to treat the symptoms of menopause, but have been associated with a proliferative effect on the uterus that can lead to an increased risk of uterine cancers. Co-administration of a PR agonist reduces or ablates that risk.
Jones et al (U.S. Pat. No. 5,688,810) described the PR antagonist dihydroquinoline A.
Jones et al described the enol ether B (U.S. Pat. No. 5,693,646) as a PR ligand.
Jones et al described compound C (U.S. Pat. No. 5,696,127) as a PR ligand.
Zhi et al described lactones D, E and F as PR antagonists (J. Med. Chem. 41, 291, 1998).
Zhi et al described the ether G as a PR antagonist (J. Med. Chem. 41, 291, 1998).
Combs et al disclosed the amide H as a ligand for the PR (J. Med. Chem. 38, 4880, 1995).
Perlman et al described the vitamin D analog I as a PR ligand (Tetrahedron. Lett. 35, 2295, 1994).
Hamann et al described the PR antagonist J (Ann. N.Y. Acad. Sci. 761, 383, 1995).
Chen et al described the PR antagonist K (Chen et al, POI-37, 16th Int. Cong. Het. Chem, Montana, 1997).
Kurihari et al described the PR ligand L (J. Antibiotics 50, 360, 1997).
Kuhla et al claimed the oxindole M as a cardiotonic (WO 86/03749).
Weber claimed the oxindole N for cardiovascular indications (WO 91/06545).
Fischer et al claim a preparation for making compounds which include the generic structure O (U.S. Pat. No. 5,453,516).
Singh et al described the PDE III inhibitor P (J. Med. Chem. 37, 248, 1994).
Andreani et al described the cytotoxic agent Q (Acta. Pharn. Nord, 2, 407, 1990).
Binder et al described structure R which is an intermediate for preparing COX II inhibitors (WO 97/13767).
Walsh (A. H. Robins) described the oxindole S as an intermediate (U.S. Pat. No. 4,440,785, U.S. Pat. No. 4,670,566).
R1=F, Cl, Br, alkyl, NH2
R2=alkyl, alkoxy, F, Cl, NH2, CF3
Bohm et al claim the oxindole T as cardiovascular agents (WO 91/06545).
Bohm et al include the generic structure U (WO 91/04974).
A Japanese patent contains the generic structure V (JP 63112584 A).
Boar et al described the dioxolane W as an intermediate for preparation of acetyl-cholinesterase inhibitors (WO 93/12085 A1).
Kende et al described methodology for preparing 3,3-substituted oxindoles, e.g., X, that was utilized in the present invention (Synth. Commun. 12, 1, 1982).
There are numerous literature reports that disclose a number of benzoxazin-2-ones. However, none of these examples in these patents contain substituents necessary for the compounds to be active as progesterone receptor modulators.
Among these publications, Narr et al (German Patent, DE 3633861, CA 109:22973) claimed that imidazobenzoxazinones, e.g. Y, as cardotonics; Benzoxazin-2-ones, such as brofoxine (Z), being active as an anxiolytic was reported by Hartmann et al (Proc. West. Pharmacol. Soc. 21, 51-55 (1978)). More recently, a number of patents (e.g., Young et al WO95/20389; Christ et al. WO98/14436) claimed quinazolin-2-ones and benzoxazin-2-ones such as compounds AA and BB as inhibitors of HIV reverse transcriptase.

Abstract: wherein T is O, S, or absent; R1, and R2 are each, independently, hydrogen, alkyl, substituted alkyl; or R1 and R2 are taken together form a ring and together contain xe2x80x94CH2(CH2)nCH2xe2x80x94, xe2x80x94CH2CH2CMe2CH2CH2xe2x80x94, xe2x80x94O(CH2)pCH2xe2x80x94, xe2x80x94O(CH2)qOxe2x80x94, xe2x80x94CH2CH2OCH2CH2xe2x80x94, or xe2x80x94CH2CH2NR7CH2CH2xe2x80x94;

Abstract: n=1-5; p=1-4; q=1-4;

Abstract: R3 is hydrogen, OH, NH2, alkyl, substituted alkyl, alkenyl, substituted alkenyl, alkynyl, substituted alkynyl, or CORA;

Abstract: RA is hydrogen, alkyl, substituted alkyl, alkoxy, substituted alkoxy, aminoalkyl, or substituted aminoalkyl;

Abstract: R4 is hydrogen, halogen, CN, NH2, alkyl, substituted alkyl, alkoxy, substituted alkoxy, aminoalkyl, or substituted aminoalkyl;

Abstract: R5 is hydrogen, alkyl, or substituted alkyl;

Abstract: R6 is hydrogen, alkyl, substituted alkyl, or CORB,

Abstract: RB is hydrogen, alkyl, substituted alkyl, alkoxy, substituted alkoxy, aminoalkyl, or substituted aminoalkyl;

Abstract: R7 is hydrogen or alkyl; or a pharmaceutically acceptable salt thereof


A sample and hold circuit is disclosed in which differentially coupled input stages are multiplexed to drive a common output stage. In this way, a plurality of input stages can be employed wherein the transition between sample and hold modes produces greatly reduced switching transients. The circuit has very high overall gain so that sampling accuracy is improved and a very low current input stage configuration permits the use of small hold capacitors without introducing excessive droop in the hold mode. The differential balance is completed by a dummy hold capacitor which is switched along with the hold capacitor. Both of these capacitors are switched in a virtual ground configuration. Also, disclosed are means for producing an auto zero input condition, means for adding a correlation feature for improved digital performance and means for injecting controlled offset potentials so that the sample and hold means can be employed as either a DA converter or an AD converter in either a pipelined or recirculating converter state.

1. Field of Invention
The field of this invention is related to track-and-hold or sample-and-hold (S&H) circuits. The two terms are normally used interchangably with the slight distinction that there are indeed some sample-and-hold designs that are not capable of tracking a voltage over a period of time, but only of sampling the voltage at a given time and then holding the voltage. For instance, most sampling oscilloscopes use a diode bridge sampler, which because of design constraints needed to obtain high input bandwidth with minimum power, is only capable of sampling and holding as opposed to tracking, sampling and holding. This nomenclature S&H, will be used throughout this patent specification.
The two most important specifications for a high performance S&H are resolution and bandwidth. Since as much as 90% of the commercial applications for S&H are for A-D converters the most relevant way to specify S&H's is in relation to their suitability for a given A-D converter specification. Thus, the resolution is usually specified in number of bits and the maximum sample frequency at which that bit-wise resolution can be guaranteed.
It is generally recognized that for resolutions above 10 or 11 bits, which correspond to a fractional resolution of 1 part in 1024 to 1 part in 2048, it becomes necessary to employ a high accuracy feedback amplifier. Simpler configurations that rely on only switches, capacitors and open loop amplifiers are generally not qualified for 12 bit or higher accuracy requirements because 1 part in 4096 linearity cannot be sustained without feedback. This invention is specifically concerned with configurations that employ feedback in both the tracking/sampling mode as well as in the hold mode.
Specifically, S&H configurations will be described that employ multiplexed feedback amplifier configurations with at least two sets of potentially active differential, dual differential or single-ended inputs and one or more sets of differential or single-ended outputs. Sarkissian 1972 U.S. Pat. No. 3,638,131, teaches how to use series diodes to isolate current mode multiplexed differential amplifiers, Series switches on the inputs is another well-known method of multiplexing. Figures of merit for multiplexed feedback amplifiers include cross-talk or input to output isolation, gain error, offset, etc. As will become clear, all these characteristics of a multiplexed feedback amplifier will determine the corresponding specifications for the S&H that incorporates the multiplexed amplifier.
2. Background of the Invention
Since S&H's are mainly included in a given A-D converter design, due to accurate requirements, it is useful to consider broad groupings of S&H methods based on accuracy. The simplest S&H is simply a series switch charging a single capacitor. The primary disadvantage is lack of isolation in the hold mode. Such first order designs require large hold capacitors for accuracy which reduces the bandwidth of the switch series resistance charging such a large capacitor. Also, the switch usually feeds through some charge in the transition from on to off (i.e., tracking to holding) and the switching charge feedthrough as well as the time at which the sampling occurs are generally not constant with input signal level. These variable effects introduce systematic harmonic distortion that is signal level dependent. Also, slew rate dependent variations of the effective sample time can occur depending on the method of actuating the on to off transition of the series switch.
It is an object of the present invention to reduce these sources of systematic harmonic distortion by providing configurations that employ a ground referenced series switching configuration. In this way, input signal level variations are never experienced by the switch, only slew dependent dynamic current loading is experienced, which is minimized if the switch transistors are properly sized in relation to the dynamic current variation to maintain a high effective F.sub.T. It is a further object of this invention to provide differential cancellation of the switching transition charge feedthrough. This allows for the use of a larger switch/capacitor ratio which increases available bandwidth and/or reduces IC die size and power.
DC offset errors are also very important for A-D converter applications and multiplexed amplifiers have more sources of errors than do ordinary op-amps. It is a further object of this invention to provide S&H configurations that can effectively reduce the DC errors by employing an auto-zero capability. If the auto-zero cycle capability is invoked during each sample/hold cycle then an added advantage is that low frequency noise (1/f), up to about 1/3 of the sampling frequency, can be effectively eliminated.
It is generally recognized that differential signal coupling is advantageous for integrated circuit A-D converter applications. Ground and power supply noise are transformed into common mode noise sources that leave the differential signals unperturbed. However, most signal sources of interest are usually supplied in single-ended form. Transformer coupling is not preferred because of expense and lack of D-C coupling. There are indeed feedback amplifier configurations that can accomplish a single-ended to diferential translation and it is a further object of this invention to provide complete S&H functions that provide a single-ended input signal capability with a differential output signal capability.
Charge-coupled devices (CCD's) have unique signal handling capabilities that require more complex S&H configurations. Specifically, CCD's have a multi-phase clock whereby there is a reference signal output phase and signal output phase. The real signal that is desired for the highest SNR performance is the difference between the reference and signal. The signal that represents this difference is called a double correlated sample and such systems of sampling are generically referred to as double correlated sampling. The ability to output such a signal is not intrinsic to CCD's themselves, but must be added with appropriate S&H functions. Usually, two separate S&H's are required as well as a method of subtracting the two values. It is a further object of the present invention to provide S&H means that directly provide double correlated sampling capability using only one multiplexed amplifier and that, further, this be made possible with zero offset correction capability.
The general field of A-D converter designs that can usefully employ an S&H include successive approximation, pipelined successive approximation and recirculating. The minimum complexity recirculating A-D converter requires several S&H functions, a gain of two amplifier capability, a 1 bit D-A offsetting capability and a 1 bit flash A-D, as well as the necessary control signals and digital logic. Recirculating A-D converters are very hard to manufacture because of the difficulty in maintaining an exact gain of two amplifier with zero offset as well as of supplying the D-A offsetting function with absolute 16 bit linearity. It is a further object of the present invention to provide an S&H function that has two distinct signal input capabilities, each of which can be selectively held on the output, that has a high accuracy gain of two transfer function, that uses double correlated sampling type capabilities to selectively actuate a 1 bit D-A offsetting capability and that is also capable of zero offset correction for each of the input signal capablities, all to a high accuracy capable of supporting 16 bit recirculating A-D converter configurations.

Current mode multiplexed sample and hold circuit


The present invention relates to bow rests which are portable, lightweight and easily adjustable. The bow rests of the present invention generally comprise a plate wherein an opening is formed in a first end section of the plate and the second end section of the plate is bent such that an angle is formed between the plane of the first end section and the plane formed by the second end section. A mount, which is configured to be fixed to a bow is pivotally attached to the second end section. The opening is adapted and configured such that a shaft such as, for example, walking/wading sticks, staffs, canes and tree limbs can be inserted through the opening and the height of the bow rest above a surface can be quickly and easily adjusted. The bow rest is adapted and configured such that the weight of a bow is transferred to the bow rest and shaft thereby improving the accuracy of a sportsman shooting the bow.

The present invention relates to versatile bow rests and more specifically to bow rests that are both compact and readily available. Additionally, the present invention relates to a method for improving the accuracy of a sportsman.
It is well known that a shooter""s accuracy is increased through the use of a gun rest. However, the use of bow rests to improve the accuracy of arrows fired by sportsmen have generally been overlooked.
Many devices have been fabricated to improve the accuracy of a sportsman using a bow such as, for example, stabilizers, sights and chin rests but none of these devices support the weight of the bow.
U.S. Pat. No. 4,674,472 describes a bow hip rest which is designed to transfer the weight of the bow from an archer""s arm to his hip. This bow rest consists of a rod with a hip rest attached to one end while the other end is configured to be mounted on the hand grip of a bow. The rod extends rearward before being angled downwards such that it extends behind the bowstring. This bow rest can be adjusted to accommodate archers with different arm lengths by utilization of a two-part, externally threaded rod and an internally threaded coupling, or custom fitted to an individual.
This bow rest can be manufactured to be lightweight but it is not readily adjustable to accommodate different shooting postures that may be necessitated by terrain or location such as, for example shooting uphill, downhill or from a tree stand. Additionally, the design of this bow rest results in the hip rest extending behind the bowstring. Many archers carry their bows at their side while walking and the rod extending behind the bowstring would make such a carrying posture uncomfortable.
Thus there exists a need for a compact, portable, lightweight bow rest that is quickly and easily adjusted over a wide range of heights such that a sportsman can take advantage of the most comfortable and convenient posture as dictated by the terrain of hunting situation.
The present invention relates to bow rests which are compact, lightweight and readily height adjustable. This ease of adjustment allows a sportsman to quickly adapt the rest to the body posture dictated by the terrain and situation.
A bow rest in accordance with one embodiment of the present invention comprises a plate. A first end section of the plate has an opening which is sized such that a shaft may be inserted into the opening. A second end section of the plate is angled from the plane formed by the first end section of the plate and configured to be pivotally attached to a mount on a bow. Upon insertion of a shaft into the opening, with the angled end being on the bottom side of the bow rest, a sportsman can adjust the bow rest to the proper height on the shaft. Any variety of shafts may be employed such as, for example, walking/wading sticks, staffs, canes and tree limbs. The weight of the bow will serve to tightly hold the bow rest in position on the shaft thereby removing the weight of the bow from the sportsman as well as providing a steady base to improve accuracy.
Embodiments of the present invention have teeth formed into the opening or the opening covered by flexible gripping aids to aid in gripping the shaft to act as a stable support for the bow. The flexible gripping aids further serve to silence the bow rests.
A bow rest in accordance with another embodiment of the present invention comprises a plate. A first end section of the plate is adapted and configured to be inserted into a preformed slit on a shaft. A support arm is permanently attached to the plate and extends downwards from the plane formed by the plate with a terminal end directed towards the first end. The support arm is adapted and configured to be inserted through the preformed slit. When the weight of a bow is applied to the bow rest the first end and terminal end serve to hold the bow rest at a desired height on the shaft. A second end section of the plate is angled from the plane formed by the plate and configured to be pivotally attached to a mount on a bow. Upon insertion of the bow rest into the preformed slit, with the angled end being on the bottom side of the bow rest, a sportsman can adjust the bow rest to the proper height on the shaft.
The bow rests of the present invention may be constructed from any material displaying the necessary rigidity to support the weight of a bow. Such material, for example, may be steel, aluminum, other metallic materials, composite materials, polymeric materials, wood or glass.
The bow rests may be fitted into the receptacle of a mounting bracket, which may either be used on a flat surface or attached to a surface by means of pressure plates and a tightener, to further stabilize the bow rest and thereby increase the accuracy of the sportsman using the bow rests.