A method and system are provided for removing water/fuel mixture from a water/fuel separator. The method injects the water/fuel mixture is injected into an exhaust aftertreatment device where the fuel portion of such mixture is burned and converted into water and carbon dioxide. The water/fuel mixture is injected as a dose, the timing of the injection being a function of the temperature of exhaust gas from the engine.

As is known in the art, the use of water separators in diesel engine fuel filters is a well-known expedient to rid the oil of materials that might cause a degradation of engine performance. Many of these consist merely of a water drainage reservoir at the bottom of the fuel filter connected by a drain tube simply to the ground or possibly to a container. Some are automatically operable; others, not. For example, some contain sensors activated when the water reaches a predetermined level in the reservoir to energize a signal light located on the dashboard of the vehicle to warn the driver of the need to drain the filter. Others include electrical means to operate a solenoid valve to automatically open the drain to a discharge pipe. In most cases, the drain is simply a drain to ground.
The inventors herein have recognized a disadvantage with the prior art approaches. Namely, inventors recognized that the material collected in the separator contains a water/fuel mixture, wherein the fuel portion of the mixture may be used to reduce fuel consumption and improve emission control of the engine. In particular, the mixture may be burned in an exhaust aftertreatment device thus increasing its temperature and the temperature of any downstream exhaust aftertreatment devices. Additionally, the fuel in the water/fuel mixture may be used as reductant to reduce NOx in a NOx-reducing aftertreatment device, such as an active lean NOx catalyst (ALNC).

Method and system to automatically drain and dispose of accumulated water from water/fuel separators in diesel


Within an integrated circuit, a contact plug with a height not extending above the level of the gate/wordline nitride is nonetheless provided with a relatively large contact area or landing pad, significantly larger than the source/drain region to which the contact plug is electrically connected. Methods for producing the inventive contact plug include (1) use of a nitride facet etch, either (a) during a nitride spacer formation etch or (b) during a BPSG etch; (2) using at least one of (a) an isotropic photoresist etch or partial descum to narrow BPSG spacers above the gate/wordline nitride, and (b) a nitride step etch to etch the shoulder area of the gate/wordline nitride exposed by a BPSG etch; and (3) polishing a BPSG layer down to the top of a gate/wordline nitride before any doped polysilicon plug fill, masking for BPSG etch and performing a BPSG etch, etching the photoresist layer through a partial descum, and etching the shoulder area of the gate/wordline nitride exposed thereby.

1. The Field of the Invention
The present invention relates to the manufacture of semiconductor devices. More particularly, the present invention is directed to novel processes for forming self-aligned polyplugs having large contact areas.
2. The Relevant Technology
FIG. 1 is a flow diagram of selected steps of a conventional process flow for producing DRAM circuits on a silicon substrate, which steps are relevant to the present invention.
At the beginning of the process flow of FIG. 1, silicon wafers have already been processed to the point that gate structures of the DRAM circuits are formed upon the substrate. Nitride is then deposited in the first process step to enclose the gate structures. In the second step, the nitride layer is vertically anisotropically etched to leave only the vertical portions of the layer. In the third step, a thin layer of nitride is redeposited over the gate structures and the substrate.
According to the fourth step of the process flow of FIG. 1, a borophosphorous silica glass ("BPSG") layer is then deposited on the surface of the wafer and flowed or densified to fill the surface features of the wafer. The BPSG forms a dielectric planarization layer. Upon the resulting relatively flat BPSG surface, a plug mask in the form of a patterned photoresist layer is produced in the fifth step using standard photolithography techniques. The resist layer is patterned to shield those areas in which no polysilicon plug is to be formed. In the sixth step, a vertical anisotropic BPSG etch removes the BPSG not vertically shielded by the patterned photoresist layer. In the seventh step, a vertical anisotropic nitride etch removes the nitride layer deposited in the third step, so that the polysilicon plugs can contact the source/drain regions. In the eighth step, the patterned photoresist layer is removed from the wafer.
In the ninth step of the process flow of FIG. 1, doped polysilicon is deposited upon the wafer surface to fill the areas left open by the BPSG and nitride etches. In the tenth step, the polysilicon on the wafer surface is gradually removed from the top downward by chemical mechanical polishing ("CMP"), or dry etch-back, to leave poly plugs only.
FIG. 2 shows a portion of a typical cross section of a partially formed DRAM device after processing through step 5 of the process of FIG. 1.
With reference to FIG. 2, three gate stacks 20a, 20b, 20c have been formed upon a silicon substrate 10. Gate stack 20a includes a doped polysilicon gate 24a topped with tungsten silicide 26a and a thick nitride layer 27a. Polysilicon gate 24a is separated from silicon substrate 10 by gate oxide 22a. The components of the gate stacks 20b, 20c are as described with respect to the like numbered components of gate stack 20a.
Gate stacks 20a, 20b, 20c are enclosed laterally by nitride spacers 28, which have been formed by nitride deposition followed by an anisotropic nitride etch. A second, thin layer nitride deposition has produced nitride film 29. A BPSG layer 30 has been deposited on and flowed over nitride film 29. A patterned photoresist layer 32 has been formed on BPSG layer 30 by photolithography techniques.
FIG. 3 shows the cross section of FIG. 2 after processing through step 6 of the process of FIG. 1, where step 6 is an anisotropic etch of the BPSG layer. The anisotropic BPSG etch has good selectivity of the BPSG layer 30 against the nitride of film 29, leaving nitride film 29 intact with little or no etching thereof, while removing the portions of BPSG layer 30 not shielded by the photoresist.
FIG. 4 shows the cross section of FIG. 3 after processing through steps 7 and 8 of the process of FIG. 1, an anisotropic nitride etch and a photoresist strip. The nitride covering gates 24a, 24b, 24c, is shown for convenience as an undifferentiated nitride layer 31. The anisotropic nitride etch has uncovered source/drain contact regions 34, 36, 38, 40 in silicon substrate 10, and etched small steps 42 into nitride layer 31 covering gates 24a and 24c. Patterned photoresist layer 32 has been removed by the photoresist strip.
FIG. 5 shows the cross section of FIG. 4 after doped polysilicon plug fill and chemical mechanical polishing (CMP) or dry etch-back to a first depth in accordance with steps 9 and 10 or 10A of the process of FIG. 1. Polyplugs 44, 46, 48 have been formed. The CMP or dry etch-back has been applied long enough to isolate plugs that should be isolated according to the circuit layout, but short enough to permit, where desired, local interconnect across gates, such as with polyplug 46 which interconnects across gate 24b. The top surfaces of polyplugs 44, 46, 48, respectively, constitute landing pads 50, 52, 54 for metal contact by a subsequent metalization layer or for contact by other subsequent contact or interconnect layers.
FIG. 6 shows an alternative cross section of FIG. 5 processed according to steps 9 and 10 of the process of FIG. 1, but with the CMP or dry etch-back step performed to a second depth greater than the first depth of FIG. 5. This second depth extends to the level of the top of nitride layer 31. Polyplugs 56, 58, 60, 62 are formed having, respectively, landing pads 64, 66, 68, 70.
CMP or dry etch-back to the second depth seen in FIG. 6 has certain advantages over CMP or dry etch-back stopping at the first depth seen in FIG. 5. First, CMP or dry etch-back to the second depth results in polyplugs having landing pads which are self-aligned with the nitride-enclosed gate structures. Second, a major goal of CMP or dry etch-back is to provide a precisely planarized surface for subsequent processing steps. CMP to the second depth improves the flatness of the polished surface above that of typical CMP because nitride layer 28 polishes away at a much slower rate than both BPSG layer 30 and the doped polysilicon material which forms the polyplugs. Thus polishing is slowed in those areas in which the nitride is reached earliest, resulting in a more even polishing compared to polishing that extends only to the first depth seen in FIG. 5.
The advantages of polishing to the second depth seen in FIG. 5 are tempered by the disadvantages of the small size of landing pads 64, 66, 68, 70. Small landing pads increase the criticality of subsequent alignment steps. A contact etch generally etches both nitride and oxide, so that any misalignment can result in contacts which short between source/drain regions and gates/wordlines. Small landing pad areas also increase the resistance at the contact material/doped polysilicon interface. It would thus be a significant advance to provide the advantages of CMP to the second depth seen in FIG. 6 without the inherent disadvantages of small landing pads.
Even where CMP or dry etch-back is performed only to the first depth shown in FIG. 5, large landing pads do not result if the width of the gate stacks is already at the limit of the resolution of the photolithography system employed. At the resolution limit, the line width of patterned photoresist layer 32 is as shown by outline O in FIG. 2. As seen in FIG. 2, the line width of patterned photoresist layer 32 at the resolution limit approaches the width of gate stacks 20a, 20b, 20c. This results in narrower polyplugs, shown in FIG. 5 by outline N, having smaller landing pads, even with CMP or dry etch-back only to the first level shown in FIG. 5. For gates or wordlines at the resolution limit, a method to increase the size of contact plug landing pads is thus needed, regardless of whether CMP to the second depth shown in FIG. 6 is employed.


A capacitor device includes: a film capacitor element that has a coiled body in which an insulating layer and an electrification layer are laminated and wound together, and a pair of collector electrodes that are formed upon two opposite end faces of the coiled body; a case that has a capacitor housing portion within which the film capacitor element is received; a pair of inserts having insulation properties, one of which is inserted between one of the pair of collector electrodes and one of inner walls of the capacitor housing portion; and a mass of sealing and insulating material that is charged between the film capacitor element and the one of the inner walls of the capacitor housing portion.

1. Field of the Invention
The present invention relates to a capacitor device and to an electrical power conversion device.
2. Description of Related Art
For some years now, the market for hybrid automobiles (HEV: Hybrid Electric Vehicle) and for electric automobiles (EV: Electric Vehicle) has seen rapid spread and development, and as a result there have been greater and greater demands upon electrical equipment for HEVs, such as batteries, inverters, motors and so on, in terms of requirements for higher output, better compactness, and lower cost. In particular, there are great demands upon inverter devices to be used for HEVs and EVs for increase in voltage, higher density, and better compactness, in order to implement lower fuel consumption, reduction of electrical power consumption, and reduction of the space occupied.
Apart from incorporating a power module that contains power semiconductor elements such as IGBTs or the like and bus bars and so on, an inverter device is assembled from components such as capacitors (DC-link capacitors) for smoothing DC power and so on. In particular, as a capacitor for an inverter device for an HEV or an EV, since the voltage that is used is several hundreds of volts, in many cases a film capacitor having high withstand voltage is principally used. Apart from film capacitors being distinguished by having high withstand voltage, the fact that, unlike other types of capacitor, they have the strong points of low loss, a long maintenance free life, and the self-healing characteristic consisting of the capability to recover by themselves when their film insulation has broken down, may also be advanced as reasons why they are often employed in HEVs and EVs.
Generally, film capacitors are made by vapor depositing a metal such as aluminum or the like upon at least one surface of an organic dielectric film made from PET (polyethylene terephthalate), PP (polypropylene), or the like, thus producing a metallized film, winding up two superimposed layers of this metallized film, and manufacturing two metallikon electrodes by metallizing the end surfaces of the wound up capacitor element with a metal such as aluminum or zinc, in order to bring electrodes out to the exterior.
In a capacitor device for an inverter device for an HEV or an EV, for example, terminals for electrical connection to other components are connected to these metallikon electrodes at the two ends of the film capacitor element by welding or soldering or the like. In many cases, the film capacitor element is then housed in a resin case that is made from PPS (polyphenylene sulfide) resin, PBT (polybutylene terephthalate) resin, or the like, and the space between the resin case and the film capacitor element is sealed with an insulating and sealing resin (i.e. a potting resin) such as epoxy resin, urethane resin, or the like, whereby a sealed capacitor module is manufactured. The insulating and water-proof characteristics of this film capacitor element are ensured by the resin case and the potting resin.
A capacitor device in which a case made from resin is used is light in weight and is excellent in heat resistance, but, under conditions in which the output electrical current is large and high ripple currents flow in the capacitor, the generation of heat by the internal capacitor element becomes high, and, due to the resin material from which the case and the potting are manufactured, this heat accumulates in the interior of the capacitor device, so that there is a danger of deterioration of its electrical characteristics such as its breakdown voltage and so on. On the other hand, it is per se known to manufacture the case from an electrically conductive metallic material and to flow potting resin into the space between the capacitor element and the case, so that a good insulating characteristic and a good heat dissipation characteristic can both be obtained. In other words, it is per se known to manufacture a capacitor device by inserting the capacitor element into a case that is made from metal while orienting the metallikon electrodes on opposite sides of the capacitor element towards the opening at the top of the case and towards the bottom surface of the case, and by potting a resin material that has high thermal conductivity into the case between its bottom surface and the lower side of the lower metallikon electrode, while potting a resin material that has high mechanical strength into the other spaces between the case and the capacitor element. With this capacitor device, it is possible to dissipate heat generated by the capacitor element to the metallic case via the high thermal conductivity resin layer that is formed in the lower portion of the case (refer to Patent Document Japanese Laid-Open Patent Publication 2006-196680).

Capacitor device and electrical power conversion device


Systems and processes may access data using a generic graph framework or other graph interface upon request from a business application. Some data retrieved by the interface may be organized as an acyclic graph structure that includes some temporal, time-based, or otherwise time-dependent nodes. In some cases, the acyclic graph may include one or more time-dependent relations. As the datasets are time-dependent, the parents/children can be processed based on their identifiers in combination with the corresponding validities. Additionally, the actual validities during evaluation of the graph may yet to be computed for each element out of the validities of its predecessors. This accessed data, with at least some time-dependent data, can be compared to a validity period provided by the business application to generate a graph valid for the validity period.

Related data often may reside in various graph structures. Generally, graphs are abstract data structures that include of a set of nodes and a set of edges that establish relationships between the nodes, such as parent-child and so forth. Business modules, or other software applications used by businesses and entities, may access and/or process data in different graph forms, such as anonymous and identified graphs. Anonymous and identified graphs may need different attributes to instantiate the graphs. For example, accessing anonymous graphs generally requires some knowledge of root nodes and may not be easily accessed since anonymous graphs are runtime graphs that may exist on a volatile memory of the system. Identified graphs are often obtainable through a global unique identifier (GUID) of a business interface since they reside on a repository.
Other graphs may be time-dependent. This normally means the nodes and relations the graph consists of are only valid for a defined time period. This may require a more sophisticated evaluation of the graph structure than for non-time-dependent graphs. Evaluation of a graph in this context means building the real structure at runtime of a software application out of the datasets of the graph's elements (nodes and relations) including the corresponding validities. This may help answer questions like "what are the child nodes (successors) of the given node?"
In some cases, applications may take care of legacy persistencies (such as DB tables of the legacy system) without the need for migration. For example, these applications are often based on a pull-mechanism, which often indicates that the applications are not getting the data they work on from the caller itself but are responsible for the data retrieval. But the graphs stored in these persistencies are normally persistence-dependent.

Validity path node pattern for structure evaluation of time-dependent acyclic graphs


An eddy current device for inspecting a component includes an eddy current array circuit having respective pluralities of drive and sense elements and having an active face for positioning on a surface of the component during the inspection operation. A backing is disposed on a face of the eddy current array circuit opposite to the active face for concentrating an electromagnetic flux from the eddy current array circuit into the component when each of the plurality of drive elements is being energized. A mechanical arrangement is provided for supporting and deploying the backing and the array circuit to substantially conform with the surface portion under inspection and to cause each of the pluralities of drive and sense elements to be maintained at their respective substantially constant distances from the inspection surface during scanning, preferably at a controlled rate of scan.

The present invention relates to the inspection of components using eddy current technology and, more particularly, to a device for inspecting a component having a complex geometric shape, such as a dovetail slot, gear tooth or the like of a gas turbine engine component or similar workpiece using a multiplicity of eddy current probe or circuit elements formed in an array to provide inspection of a larger surface area in a shorter time than has heretofore been available with a substantially lower probability of missing a flaw or defect.
Eddy current inspection is a commonly used technique for detecting discontinuities or flaws in the surface of components such as the components of a gas turbine engine. Eddy current techniques are based on the principle of electromagnetic induction in which eddy currents are induced within the component under inspection. The eddy currents are induced in the component by alternating magnetic fields created in a coil of an eddy current probe, referred to as a drive coil, when the probe is moved into proximity with the component under inspection. Changes in the flow of eddy currents are caused by the presence of a discontinuity or a crack in the test specimen. The altered eddy currents produce a secondary magnetic field which is received by the eddy current probe coil or by a separate sense coil in the eddy current probe which converts the altered secondary magnetic field to an electrical signal which may be recorded on a strip chart or similar device for analysis. An eddy current machine operator may then detect and size flaws by monitoring and analyzing the recorded signals. Flaws or defects are detected if the electrical signal exceeds a predetermined voltage threshold.
Referring to FIG. 1, a present method of inspecting a component 10, such as a dovetail slot of a rotor, spool or disk of a gas turbine engine, as shown in FIG. 1, uses a single eddy current probe which will typically have two coils connected in a bridge circuit for simultaneous driving and sensing. The single eddy current probe 12 is moved linearly, as indicated by arrow 14 across the interior surface 16 of dovetail slot 18 to scan the surface and detect any flaws or defects present therein. After a complete scan across interior dovetail slot surface 16 in direction 14, the single eddy current probe 12 is indexed or incrementally moved to a next scan location 12' as shown in phantom in FIG. 1. The probe at location 12' is then scanned again across the interior surface 16 of dovetail slot 18. This systematic process of scanning and indexing the single probe 12 is repeated until the entire interior surface 16 of dovetail slot 18 desired to be inspected has been scanned. This single probe/line scan procedure typically requires an extended period of time to substantially completely and adequately inspect the desired surface area even for relatively small dovetail slots and will take even longer as the slot size increases for larger disks and rotors. Additionally, the eddy current probe 12 must be carefully indexed each time so that no area and any small flaws within this area will be missed.

Eddy current device for inspecting a component having a flexible support with a plural sensor array


The sampling system of the invention includes a column comprising a first separator associated with a first collector so as to extract particles whose diameter is larger than a first diameter, and a second separator associated with a second collector which eliminates the finest particles and concentrates the other particles in the gas flow sucked up by the suction pipe of an analysis device.

1. Field of the Invention
The present invention concerns a system for taking a gas sample able to contain suspended materials, such as particles.
It applies in particular, but not exclusively, to the analysis of gas composition and/or to counting of particles present in this composition via a spectrographic analysis of the radiation produced by flame of a gas mixture including said composition.
2. Description of the Prior Art
It is known that this type of analysis is conducted by using a flame spectrophotometer including a burner in which combustion is provoked of a gas mixture flow comprising the gas composition to be analysed (for example ambient air) and hydrogen or other oxygen carrier so as to embody a flame whose light emissions are decomposable in a light spectrum whose spectrum lines are analysed so as to determine the nature and concentration of the sought-after elements.
The gas mixture flow is generated by creating a partial vacuum in the outlet circuit of the burner, for example by means of a turbine, sop as to provoke at the level of an intake circuit a sucking up of the gas composition to be sampled.
The advantage of this type of device resides in particular in that it makes it possible to conduct, not only the analysis of the gas composition, but also to determine the composition and the numeration of particles (for example bacteria or dust) present in this composition.
In fact on burning, these particles generate light impulses (flash) of limited duration able to count so as to obtain the number of particles per unit of volume of the gas composition to be analysed.

System for taking a gas sample able to contain particles of suspended materials


An electronic component assembly having thermal pads with thermal vias coupling an image sensor and a camera board fab is provided for heat dissipation. The electronic component assembly can include: a circuit board having at least one thermal pad disposed on a top surface of the circuit board; and an image sensor disposed on the top surface of the circuit board, having at least one conductive pad disposed at at least one corner of the image sensor. The at least one thermal pad is coupled to the at least one conductive pad of the image sensor and the at least one thermal pad is formed with a plurality of first thermal vias penetrating the thermal pad and the circuit board for transfer of heat of the image sensor.

Instruments and apparatus systems that are used for viewing, recording, and analyzing the results of biological and chemical tests and assays often require instrumentation such as a charge-coupled device (CCD) camera, a complementary metal-oxide-semiconductor (CMOS) imager, or other such image sensor. The older CCD and CMOS package designs as shown in FIG. 1, left a lot of room on the back side of the image sensor to attach cold fingers for heat dissipation. For instance, FIG. 2(a) provides a schematic representation of Sony ICX 695 CCD image sensor with the box area indicating an area where the cold fingers could contact the image sensor.
However, the more modern CMOS image sensor, such as a Sony IMX 178 image sensor shown in FIGS. 2(b) and 2(d), or a Sony IMX183 image sensor shown in FIG. 2(c), have an architecture of grid arrays and thus do not have much available areas for the cold fingers to contact for thermal dissipation.
All other things being equal, the heat conduction using a conventional cold finger is proportional to the area of the image sensor and can be determined by the following equation:
  Q  =            KA                    (                              T            Hot                    -                      T            Cold                          )              d  where:                Q=heat conduction (W)        K=material thermal conductivity (W/mK)        A=cross-sectional area        THot=higher temperature (° C. or ° K)        TCold=colder temperature (° C. or ° K)        d=material thickness
Therefore, the heat conducted out of the older image sensor Sony ICX695 (with an area of 160 mm2) of FIG. 2(a) is 18.3 times faster than the heat conducted out of the more modern image sensor Sony IMX178 (with an area of 8.75 mm2) of FIG. 2(b); and the heat conducted out of the older image sensor Sony ICX695 (with an area of 160 mm2) of FIG. 2(a) is 8 times faster than the heat conducted out of the more modern image sensor Sony IMX183 (with an area of 20 mm2) of FIG. 2(c).
Nevertheless, some existing image sensors comprise pads located at corners of the image sensor as shown in FIG. 2(d). Even if the corner pads are not directly connected with each other by vias inside body of the image sensor, the bulk heat conduction inside the body of the image sensor will pull heat away when the corner pads are cooler than the bulk silicon of the pixel plane of the image sensor.

Electronic component assembly with thermally conductive structures for image sensors


A fluid flow proportioning device including spool type valve elements (12,14,16) opposite end portions of which reciprocate in oppositely disposed and spaced apart valve block halves (100,102). So that the fluids being proportioned can never mix within the device despite the spool portions being devoid of sealing element within the cylindrical bores (13,15,17) in which they are slideable, central portions (21) of the valve elements are of smaller diameter than the diameters of the cylindrical bores (13,15,17) in which the valve elements are located, and resilient seals (105) encircle the portions (21) where they extend outwards from the valve block halves.

The invention relates to a positive displacement fluid flow proportioning device.
Fluid flow proportioning devices are required, for example, where a two-part mixture of materials is to be used for spraying a coating on metal sheets or within a metal pipeline. In such cases, the materials concerned may well be a cold setting resin material mixed with a liquid curing agent or initiator and, if so, it will be vital that the materials are mixed together in precisely the correct proportions. However, variations of temperature (and thus the viscosities of the materials concerned) as the operation proceeds can make the maintenance of the correct proportions in this particular situation very difficult indeed. In other industrial situations, for example in the manufacture of foodstuffs and pharmaceuticals, where liquids or gases are to be mixed together in exact proportions, other variables can make the maintenance of the ideal mix equally difficult.
A further difficulty in this and other situations where the materials to be mixed are particularly aggressive, for example of an abrasive nature, is that any resilient sealing means required are prone to severe wear, so much so that their frequent replacement to ensure the proper functioning of the proportioning device can make the operation uneconomic.
The object of the invention is to provide a simple fixed-ratio and relatively inexpensive fluid flow proportioning device whereby fluids can be divided accurately into two or more flows which are in some required fixed proportion to each other.
According to the invention, there is provided a fluid flow proportioning device including at least three spool type valve elements slidably located in respective cylindrical bores to which there is connected a common inlet passage for a first fluid flow under pressure, by way of respective inlet ports, a common inlet passage for a second fluid flow under pressure, by way of other respective inlet ports, respective outlet ports being spaced from the inlet ports and respective transfer ports being provided whereby, in response to sequential movements of the valve elements, one of a pair of pressure chambers at the opposite ends of each valve element is fed in turn with one of the two fluid flows under pressure admitted via one of the two transfer ports of the previously actuated element whilst a measured volume of the other fluid flow is discharged, by the movement of the respective valve element, from the other of the pair of pressure chambers via the other transfer port of the previously actuated element, whereby, as the valve elements are actuated in turn, the proportions of the two fluid flows being delivered for use are dependent on the number of pressure chambers for each fluid flow which are connected for use, the respective cylindrical bores in which the valve elements are slidably located being formed in oppositely disposed and spaced apart valve block halves, and central portions of the spool type valve elements being of relatively small diameter, that is to say smaller than the diameters of the cylindrical bores in which the spool type valve elememts are slidably located, and being provided with resilient seals where they extend outwards from the valve block halves. Each spool type valve element may be constituted by two opposite end portions and a central push-rod portion abutting together end to end. Means may be provided for intensifying pressure on the resilient seals which surround the central portions of the spool type valve elements. Provision may be made for any leakage of fluid past a valve element in a cylindrical bore of a valve block half to be ducted back to a respective holding tank for the fluid concerned. Respective baffle plates may be mounted on the central portions of said valve elements to prevent the mixing together of any leakage of fluids past the resilient seals where such mixing could be either dangerous or inconvenient.
The arrangement may be such that, in operation of the device, the pressure of one fluid flow causes movements of the spool type valve elements, in turn, in one direction and the pressure of the other fluid flow then causes movements of said elements, in turn, in the opposite direction. Alternatively, the arrangement may be such that the pressures of the two fluid flows are effective alternately, that is to say, when the pressure of one fluid flow has caused the movement of one valve element in one direction, the pressure of the other fluid flow then causes the movement of a next valve element in the opposite direction, and so on, this resulting in a smoother fluid output from the device.
The first and second fluid flows may be of different fluids and may be at different pressures, the device operating to control the flow of the respective fluids in some fixed proportion to each other, possibly for mixing together at some fixed ratio.
Alternatively, the first and second fluid flows may be taken from a single fluid supply, the device operating to divide the fluid into at least two flows in some fixed proportion to each other. If the device is to control the flow of two different fluids at different pressures, the opposite ends of the valve elements may be of different diameters to compensate for the differences of pressure; to compensate for such different diameters, that is to say to ensure that the same volume of fluid is displaced on each movement of a valve element, each valve element may be constituted by a pair of valve halves arranged to move through different distances, that is to say, being linked together for simultaneous movement by means which control the stroke of each valve half in inverse proportion to its cross-sectional area.


A voltage limiter (20) includes a resistor (21) receiving an input signal on a first terminal and providing an output signal on a second terminal, and a capacitor (22) connected between the second terminal of the resistor (21) and ground. Two transistors (23,26) biased by first and second bias voltages, respectively, are connected between the second terminal of the resistor and a second voltage terminal to clamp the output voltage between high and low voltage limits. A single-ended to differential converter (60) uses two such voltage limiters. A first voltage limiter (90) receives an input voltage, and has an output terminal connected to a positive input terminal of an amplifier (100). A second voltage limiter (92) has an input terminal connected to the second voltage terminal and an output terminal connected to a negative input terminal of the amplifier (100). A shared capacitor (83) is coupled between second terminals of resistors of the first (90) and second (92) voltage limiters.

Some circuits such as analog receivers are able to process input signals only within certain bounds of voltage, known as the input voltage range of the receiver. If an input signal is outside this range, then signal distortion and other undesirable effects occur. For example, power supply noise may be reflected in a received signal and may cause the received signal to be outside the input voltage range of the receiver's amplifiers. In this situation, it is necessary to somehow limit the received signal to upper and lower boundaries.
There are several known techniques to limit the amplitude of an input signal to the input voltage range of the amplifier. One technique compares the voltage on the input signal line with two reference voltages, corresponding to upper and lower limits of the input voltage range. If the input signal voltage exceeds the upper limit, the output of a first comparator causes a first reference voltage to be switched in, effectively clipping the input signal at the upper limit. Similarly, when the input signal voltage is less than the lower limit, a second comparator clips the input signal to a second reference voltage, effectively clipping the input signal at the lower limit. The disadvantage of this approach is that the two comparators require a significant amount of integrated circuit area.
Another voltage limiter, such as that disclosed by G. Brehmer and H. Jackson in U.S. Pat. No. 4,849,708, provides clamping transistors in feedback paths of a differential amplifier. However, this technique requires an additional differential amplifier, which consumes significant integrated circuit area and thus may not be desirable for cost-sensitive applications. Also, inserting an additional amplifier in the input signal path reduces the effective bandwidth in the receiver. In addition, such a circuit may be sensitive to power supply noise.

Voltage limiter and single-ended to differential converter using same


A balance assembly (15) is provided for a sash window assembly (10). The sash window assembly (10) has a sash window (12) slidable within a master frame (14). The balance assembly (15) has an elastomer balance member (30) having one end adapted to be connected to the master frame (14) and another end adapted to be connected to the sash window (12) to provide an upward biasing force to the sash window (12). A system (50) is provided for custom-manufacturing the balance member (30) and for custom-manufacturing a sash window assembly (10) incorporating the balance member (30).

A pivotal sash window adapted for installation in a master frame of a sash window assembly is well-known. The sash window assembly typically has opposed, vertically extending guide rails to enable vertical reciprocal sliding movement of the sash window in the master frame while cooperatively engaged with the guide rails or shoe channels. The sash window has a top sash rail, a base and a pair of stiles cooperatively connected together at adjacent extremities thereof to form a sash frame, usually a rectangular frame. Typically, a pair of spaced tilt-latches are installed on, or in, opposite ends of the top sash rail. Retracting a latch bolt in each tilt-latch simultaneously allows the sash window to be tilted inwardly. To this end, the sash window is pivotally supported at its base by a pair of sash balance brake shoes. The brake shoes slide within the guide rails which are typically in the form of channels.
A balance assembly is typically included with the sash window assembly to counterbalance the sash window within the master frame. One form of the balance assembly includes a spring that is connected at one end to a top portion of the master frame, typically within the shoe channel, and at another end to the brake shoe. The spring exerts an upwardly biasing force against the weight of the sash window. Different types of springs have been used in the balance assemblies. For example, a leaf spring is wound into a coil which is mounted to the guide rail and a free end of the spring is connected to the brake shoe. Some balance systems have been disclosed reversing the leaf spring configuration wherein the coiled end of the leaf spring is connected to the brake shoe and the free end is connected to the guide rail. Conventional spiral coil springs have also been used in balance systems. Block and tackle balance systems have also been utilized. These balance systems can be costly and can require large shoe channels to accommodate the balance systems.
In certain instances, the weight of the sash window requires increased counterbalance forces. Thus, multiple leaf springs have been used in tandem to increase these forces. Because windows can vary in size and weight, it can be difficult to specify a standard balance system that provides the most optimum counterbalance force against each sash window. As a result, window manufacturers must carry several different models of a balance systems having different sized springs that offer different counterbalance forces. This increases required inventories and factory space required to house all of the balance systems.
The present invention is provided to solve these and other problems.

System for manufacturing sash window assemblies


A determination is made whether a minimum threshold period (or frequency) change has occurred in an oscillator signal indicating the initial presence of a vehicle over an inductive sensor. The change in period of the oscillator signal is measured over each of a plurality of frame segments. A magnitude of period change in the oscillator signal is recorded. If the number of frame segments that occur between detection of the threshold change in period and the magnitude change in period is less than a predetermined number, the detector does not make a speed measurement calculation. If the number of frame segments equals or exceeds the predetermined number, the time rate of change of the period of the oscillator signal is estimated. A vehicle detector calculates a sensor entry distance for a particular vehicle. A vehicle entry time is calculated by dividing the magnitude of period change by the rate of period change. Speed is then calculated by dividing the entry distance by the vehicle entry time. The speed measurement is directed to an output by activating the output for a period of time proportional to the speed of the vehicle. Multiple vehicles may be detected by adjusting the minimum threshold period change, after each vehicle passes, by the peak change in oscillator signal period caused by that vehicle. Vehicle length may be calculated by multiplying the measured speed by the total time between vehicle entry and exit from the loop area, and subtracting the length of the detection area.

The present invention relates to vehicle detectors which detect the passage or presence of a vehicle over a defined area of a roadway. In particular, the present invention relates to a method of vehicle speed measurement using a single inductive sensor of a vehicle detector.
Inductive sensors are used for a wide variety of detection systems. For example, inductive sensors are used in systems which detect the presence of conductive or ferromagnetic articles within a specified area. Vehicle detectors are a common type of detection system in which inductive sensors are used.
Vehicle detectors are used in traffic control systems to provide input data required by a controller to control signallights. Vehicle detectors are connected to one or more inductive sensors and operate on the principle of an inductance change caused by the movement of a vehicle in the vicinity of the inductive sensor. The inductive sensor can take a number of different forms, but commonly is a wire lop which is buried in the roadway and which acts as an inductor.
The vehicle detector generally includes circuitry which operates in conjunction with the inductive sensor to measure changes in inductance and to provide output signals as a function of those inductance changes. The vehicle detector includes an oscillator circuit which produces a oscillator output signal having a frequency which is dependent on sensor inductance. The sensor inductance is in turn dependent on whether the inductive sensor is loaded by the presence of a vehicle. The sensor is driven as a part of a resonant circuit of the oscillator. The vehicle detector measures changes in inductance in the sensor by monitoring the frequency of the oscillator output signal.
Examples of vehicle detectors are shown, for example, in U.S. Pat. No. 3,943,339 (Koerner et al.) and in U.S. Pat. No. 3,989,932 (Koerner).
A critical parameter in nearly all traffic control strategies is vehicle speed. In most circumstances, traffic control equipment must make assumptions about vehicle speed (e.g., that the vehicle is traveling at the speed limit) while making calculations. Currently there are no devices available that both detect vehicles and measure vehicle speed on a real-time basis. Usually, the device to which the vehicle detector provides its outputs calculates the speed of the detected vehicle. While counter/classifier devices do contain vehicle detectors and are capable of measuring speed, they do not provide calculations to external devices in real time.
A commonly used method of measuring vehicle speed with a single loop inductive sensor is to have the detector make the assumption that all vehicles are the same length. The speed of the vehicle may then be estimated based on the time the vehicle is over the loop. This method uses the following formula: ##EQU1## where, S=speed estimate
AVL=assumed vehicle length PA0 L.sub.loop =loop length PA0 DVD=duration of vehicle detection PA0 k=constant greater than one which depends on loop geometry PA0 t.sub.VD2 =time of vehicle detection at second loop PA0 t.sub.VD1 =time of vehicle detection at first loop
Using this method, the speed estimate for any given vehicle will have an error directly related to the difference of the vehicle's actual length from the of error arising from the use of this method is due to miscalculations of the duration of vehicle detection (DVD). These miscalculations are a function of sensitivity setting, vehicle type, detector scan time, and of the scan time of the external device that is actually making the speed calculations. While this method can provide a relatively accurate measurement of the average vehicle speed, it is inadequate for measurement of individual vehicle speed.
It is desirable to achieve accuracy in the measurement of individual vehicle speed with an error of less than five percent. This degree of accuracy is difficult to achieve even with the two loop and two detector systems in common use. These two loop systems calculate speed using the following equation: ##EQU2## where, loop spacing=length of space between inductive loop sensors
This two loop method also contains several sources of possible error. First, the terms in the denominator, t.sub.VD2 and t.sub.VD1, are difficult to obtain accurately. In a scanning-type vehicle detector in which multiple inductive sensors (or "detector channels") are interrogated on a time-multiplexed basis, the actual time of vehicle entry is indeterminate by at least the length of time required to scan all of the detector channels. Similarly, the device receiving the vehicle detector's outputs will typically scan the outputs of multiple vehicle detectors. Further uncertainty results as the vehicle detector attempts to ascertain when the vehicle enters the second loop. Another source of error is vehicle bounce. Due to these sources of error, the best two loop speed measurement systems available today have a typical accuracy for any specific vehicle of plus or minus twenty percent when the vehicle being detected is travelling at freeway speeds.

Single inductive sensor vehicle detection and speed measurement

Minnesota Mining and Manufacturing Company


A pharmaceutical composition, comprising cisplatin, a special carrier and, optionally, customary pharmaceutical excipients, is disclosed. The preparation of this pharmaceutical composition is also disclosed. The composition may be used to treat cancer and Acquired Immune Deficiency Syndrome (AIDS).

Cisplatin (cis-diamminedichloroplatinum, cis-Pt(NH.sub.3).sub.2 Cl.sub.2, molecular weight 300.05) has been used as a chemotherapeutic agent for many years since the discovery of its anti-tumor activity by B. Rosenberg et al. (Nature, 1965, 205, 698;Nature, 1972, 222, 385).
After so many years, cisplatin is still being widely used because of its efficacy. It has been used to treat cancer patients for head, neck, ovarian cancer, etc. However, its major drawback, the toxicity, is still a big concern.
Many attempts have been made to modify the cisplatin molecule in order to reduce its toxicity; many other attempts have been made to understand the interaction between cisplatin and DNA, which is the ultimate target of cisplatin. A few attempts have also been made to modify the composition of cisplatin dosage form to reduce its toxicity or improve its efficacy.
In terms of modifying the cisplatin molecule, many people have attempted to change the ligand or ligands on Platinum. Examples of the modifications on cisplatin have been made by K. C. Tsou, et al.(J Clin. Hemat. Oncol. 1977, 7, 322,), R. J. Speeder et al. (J. Clin. Hemat. Oncol. 1977, 7, 210), A. Mathew et al. (Chem. Comm. 1979, 222), D. Rose, et al. (Cancer Treatment Reviews, 1985, 12, 1), and D. Alberts et al. (Cancer Treatment Reviews, 1985, 12, 83).
In terms of understanding the interaction between cisplatin and DNA, the X-ray structure of the adduct of cisplatin and DNA was determined by S. E. Sherman et al. (Science 1985, 230, 412). This critical work provides a clear insight as to how cisplatin may function as an inhibitor to stop the DNA replication process, thus, kill the cell eventually. Their studies show that cisplatin binds to synthetic oligodeoxynucleotides to form cis-[Pt(NH.sub.3).sub.2 {d(pGpG)}], where "d(pGpG)" represents dinucleotide made of deoxyguanosine monophosphate. They indicated that the intrastrand cross-linked cis-[Pt(NH.sub.3).sub.2 {d(pGpG)}] is a very possible reason why cisplatin is capable of inhibiting DNA replication. Fichtinger-Schepman et. al., (Biochemistry, 1985, 24, 707-713) synthesized and identified four adducts of cisplatin and DNA residues. They are: cis-[Pt(NH.sub.3).sub.2 d(pGpG)], cis-[Pt(NH.sub.3).sub.2 d(pApG)], cis-[Pt(NH.sub.3).sub.3 dGMP], and cis-[Pt(NH.sub.3).sub.2 (dGMP).sub.2 ], where "d(pGpG)" represents dinucleotide made of deoxyguanosine monophosphate, "d(pApG)" represents dinucleotide made of deoxyadenosine monophosphate and deoxyguanosine monophosphate, and dGMP represents deoxyguanosine monophosphate.
The most common binding of cisplatin to DNA is through the loss of chloride ion to form Pt-N bond to the N.sub.7 of guanine on deoxyguanosine. Most references indicate that N.sub.7 of guanine is the major binding site for guanosine nucleotide. Examples of the references are F. J. Dijt et al. (J Am. Chem. Soc. 1984, 106, 3644-3647), A. M. J. Fichtinger-Schepman et al. (Biochemistry 1985, 24, 707-713), and S. E. Sherman et al. (Science 1985, 230, 412-417). However, other nucleosides or deoxynucleosides are also known to bind cisplatin (chapter 9, Metal-DNA Chemistry, 1989, American Chemical Society Symposium Series 402, 119-145).
In terms of modifying the composition of the dosage forms of cisplatin, many articles were published. Cisplatin has been used in combination with caffeine by H. Yasutake et al. (Gan to Kagaku Ryoho 1989, 16, 2031-8) and by H. Tsuchiya (Kanazawa Daigaku Juzen Igakkai Zasshi 1988, 97, 543-56). Cisplatin has also been used in combination with cytosine arabinoside and the combination has shown some advantages as shown by J. Berek et al. (Obstet. Gynecol. 1989, 74, 663-6). Another combination, cisplatin and novobiocin, has also been shown to be advantageous by P. Eder et al. (Cancer Research 1989, 49, 595-8. A patent issued in 1992 (U.S. Pat. No. 5,130,145) was related to this invention. This prior art indicates that when cisplatin and L-ascorbic acid are administered simultaneously, the anti-tumor activity is higher.
None of these prior arts uses nucleoside or deoxynucleoside along with cisplatin in a pharmaceutical composition for cancer therapy. The main reason for this is that nucleosides and deoxynucleosides have not been used as pharmaceutical excipients.
This invention comprises a pharmaceutical composition comprising cisplatin, a special carrier, and, optionally, customary pharmaceutical excipients, whereas said special carrier represents one to four nucleosides, one to four deoxynucleosides, or the combination of one to four nucleosides and one to four deoxynucleosides, wherein nucleoside represents adenosine, guanosine, cytidine, or uridine and deoxynucleoside represents deoxyadenosine, deoxyguanosine, deoxycytidine, or thymidine. Said pharmaceutical excipients are customary and physiologically acceptable pharmaceutical excipients such as mannitol, lactose, sodium chloride, phosphates, water, ethanol, hydrochloric acid, magnesium stearate, cellulose, starch, polyethylene glycol, etc. Therefore, the composition may be in a liquid or solid dosage form suitable for parenteral or oral administration to a patient.
This composition is different from the conventional pharmaceutical compositions which do not contain nucleosides or deoxynucleosides.
Based on the studies of R. A. Lerner et al. (Proc. Natl. Acad. Sci. USA, 1971, 68, 1212), J. C. Rogers et al. (J. Immunol. 1981, 126, 703), J. Woo et al. (Biochem. J. 1972, 128, 1273), and D. A. Juckett et al. (Cancer Research 1982, 42, 3565), it was shown that most cancer cells have DNA or RNA sticking out of the cells. Because nucleosides or deoxynucleosides are the building blocks of RNA or DNA, it is conceivable that a drug molecule comprising available nucleoside or deoxynucleoside may be more likely to be grabbed by the DNA or RNA sticking on the outside of the cancer cells, thus, giving the drug molecule better opportunity to attack the cancer cells.
Because the preparation of this composition comprises mixing cisplatin and nucleoside or deoxynucleoside in a suitable solvent for a significant period of time, it contains some of the adducts formed between cisplatin and nucleoside or deoxynucleoside. These adducts may have stronger affinity to the DNA or RNA being replicated. Since most cancer cells are much more active in reproducing DNA or RNA, it can become a more likely target for the adduct formed between cisplatin and nucleoside or deoxynucleoside. As a result, this composition may be less toxic than cisplatin alone or cisplatin in other pharmaceutical compositions. The in-vitro results indicate that it is the case for the cisplatin/guanosine 1:1 adduct as shown in previous patent application (application Ser. No. 08/818,444).
Predominantly, cisplatin binds onto deoxyguanosine of DNA. However, cisplatin also binds onto other deoxynucleosides or nucleosides. Thus, nucleosides or deoxynucleosides, other than guanosine and deoxyguanosine, may also show similar effects in reducing the toxicity of cisplatin even though their affinity to cisplatin may not be as strong as that of guanosine or deoxyguanosine.
Therefore, this invention is a better pharmaceutical composition than other cisplatin compositions.
Because cisplatin binds onto DNA or RNA, this composition may also be used to treat viruses, such as Human Immunodeficiency Virus (HIV), to bind its DNA or RNA and kill the virus. Thus, the composition may be used for the treatment of Acquired Immune Deficiency Syndrome (AIDS) patient. The composition may also be used in combination with other well known AIDS drugs, such as 3'-azidothymidine (AZT), to interfere with the HIV enzyme reverse transcriptase and achieve the goal of hampering the reproduction of HIV.

Pharmaceutical composition comprised of cisplatin, and processes for making and using same


An injection laser driver regulates the bias and modulation depth by means of two feedback control loops, one deriving its feedback control signal from a measure of the mean optical output of the laser, and the other deriving its feedback control signal from a measure of the spectral purity of that optical output. The spectral purity measure is conveniently effected by measuring the coherence function at a specific value of differential delay using a Mach-Zehnder interferometer configuration with a passive quadrature optical network.

This invention relates to the binary modulation of injection lasers, and is particularly concerned with the regulation of the bias level and modulation depth to provide operation which on the one hand provides good extinction, while on the other hand does not produce excessive chirp. Chirp needs to be limited, particularly in a long distance transmission system, so as to avoid imposing unnecessary bandwidth limitations as a result of the pulse-broadening effects of chromatic dispersion exhibited by that system. Chirp can be limited by ensuring that the drive maintains the laser somewhat above its lasing threshold even during the lower drive current (data 0) bit periods, but the higher that the current is maintained for data 0 bit periods, the poorer the extinction.
A difficulty with trying to achieve optimal drive conditions is that the lasing threshold current, and the slope of the laser characteristic which plots light output as a function of current drive, are liable to vary not only from laser to laser, but also, in any given laser, as a function of its temperature and as a property of the ageing process of that laser.
One way of dealing with these problems is to employ two feedback control loops. One of these loops derives a feedback control signal that is indicative of the mean light output power from the laser and employs this to regulate the laser. Assuming the use of a balanced code, and a linear relationship between light output and laser drive between the data 0 drive current level i.sub.0 and the data 1 drive current level i.sub.1, the loop operates to provide a mean drive current (i.sub.0 +i.sub.1)/2. The other feedback loop derives a feedback control signal that is indicative of the lasing threshold and employs this to regulate the value i.sub.0 to be just above the lasing threshold value. If it is safe to assume that the slope of the laser characteristic between current values i.sub.0 and i.sub.1 will not vary too much, the first loop can be dispensed with. Under these circumstances the sole feedback control loop regulates the laser bias and the modulation depth (i.sub.1 -i.sub.0) is maintained at a constant preset value.
One particular way of constructing a feedback control loop to derive a feedback control signal indicative of the laser threshold current is described by D. W. Smith et al in the paper entitled `Laser Level Control for High Bit Rate Optical Fibre Systems` given at the 13th Circuits and Systems International Symposium Houston April 1980. This involves impressing a small amplitude low frequency current modulation, a ripple, upon the data `0`s, this low frequency modulation being within the pass-band of a monitor photodiode and its associated circuitry. The slope of the characteristic which plots light output as a function of drive current, changes as the drive current is increased through the lasing threshold from a relatively lower value to a relatively higher value. The ripple on the laser drive current therefore produces a corresponding ripple on the monitor photodiode current, and this is compared with a preset value to provide a feedback control signal which is employed to regulate I.sub.0 to a particular slope value intended to correspond to a point just above lasing threshold. Problems encountered with this approach are attributable to the fact that the shape of the characteristic is liable to vary from laser to laser, making it difficult to choose an optimum value of slope as the target of the feedback loop, and also to the fact that an individual laser may exhibit that target value of slope over an extended range of current drive levels in the vicinity of the optimum operating point.


A method of manufacturing a semiconductor device includes forming a first plurality of recessed regions in a substrate, the substrate having a protruded active region between the first plurality of recessed regions and the protruded active region having an upper surface and a sidewall, forming a device isolation film in the first plurality of recessed regions, the device isolation film exposing the upper surface and an upper portion of the sidewall of the protruded active region, and performing a first plasma treatment on the exposed surface of the protruded active region, wherein the plasma treatment is performed using a plasma gas containing at least one of an inert gas and a hydrogen gas in a temperature of less than or equal to about 700.

According to miniaturization of a semiconductor device having an active region of a MOS transistor, the size of the active region of the MOS transistor has been gradually reduced. Thereby, the channel length of the MOS transistor also has been reduced. If the channel length of the MOS transistor becomes smaller, a short channel effect (SCE) may occur and the operating performance of the MOS transistor may suffer.
Therefore, various studies have been conducted to increase the operating performance of the MOS transistor even though the size of the active region of the MOS transistor has been reduced. One of them is to use a fin field effect transistor (FinFET) having a fin-type active region. Generally, the fin-type active region may be formed on a substrate of the semiconductor device by partially etching the substrate using an etch process. As a result, the substrate may be damaged by the etch process and the surface roughness of the substrate may increase. If the surface roughness is not cured, the operating performance of the MOS transistor suffer.

Method of manufacturing semiconductor device using surface treatment and semiconductor device manufactured by the method

Samsung-ro, Yeongtong-gu, Suwon-si, Gyeonggi-do


A fiber-optic imaging probe is disclosed for use in dynamic light scattering applications. The probe includes two monomode optical fibers and two GRIN lenses to form a pair of identical fiber-lens combinations. Each fiber is positioned off the optical axis of its associated lens. Further, the optical fibers are placed at an image plane of the lenses. The fiber-lens combinations are parallel to and mirror images of each other. The first fiber-lens combination projects a tightly focused spot of light into a scattering volume containing suspended or dispersed microscopic particles, or biological or live tissues. The second fiber-lens combination collects the light which is scattered from the particles in the scattering volume and conveys it to a photo detector and autocorrelator for analysis. The probe minimizes the scattering volume by advantageously using imaging principles of lenses. Further, the probe optimizes sensitivity and spatial coherence. The probe provides rapid determination of particle diffusivities and their respective size distributions in the scattering volume. The probe can be combined with a video and/or microscopic imaging system for visual monitoring of the scattering volume in real time. The probe may be used in a wide variety of optical diagnostic applications. Further, the probe is easy to manufacture and use.

This invention pertains to the field of dynamic light scattering which is also known as quasi-elastic light scattering (QELS), intensity fluctuation spectroscopy (IFS), optical mixing spectroscopy, and photon correlation spectroscopy (PCS). More particularly, this invention pertains to the characterization of particle suspensions or dispersions using DLS. The invention is applicable to eye diagnostics such as the diagnosis of eye diseases (cholesterol deposit and blood sugar level in the anterior chamber, cataract in the lenses, diabetic retinopathy, age related molecular change in the vitreous, etc.) and will be described with reference thereto. However, it will be appreciated that the invention has broader applications such as monitoring the synthesis of microporous materials (e.g., zeolite), monitoring protein crystallization process, characterization of food proteins, analyzing skin and tissue, diagnosing biological fluids in situ and in vivo, on-line process monitoring, studying polymer induced aggregation and flocculation, studying highly concentrated and interacting systems, and characterizing diverse systems such as gels, solids, liquid crystals, colloidal suspensions, polyelectrolyte solutions, dispersions of microorganisms and solutions of viruses and biopolymers. Moreover, the invention may be advantageously employed in other environments and applications including static light scattering, Brillouin scattering, Raman scattering, fluorescence spectroscopy and laser doppler velocimetry and anemometry.
DLS is a widely used technique in studying the hydrodynamic properties of microscopic particles suspended in a fluid medium. Some of the information that can be obtained from DLS include the diffusion coefficient, average particle size, polydispersity, and particle size distribution.
The concept of DLS has been in use for the last half century, and numerous publications and books have been published on the subject. For example, the basic theory and experimental aspect of DLS can be reviewed in the book by Chu [Laser Light Scattering: Basic Principles and Practice, 1991].
In DLS, coherent light such as laser light illuminates microscopic particles dispersed or suspended in a fluid medium. The particles range in size from a few nanometers to a few microns. The particles scatter light over a wide range of angles by Rayleigh or Mie scattering. The intensity of the scattered light fluctuates in time due to the Brownian or thermal motion of the particles in the medium. The fluctuations of the light intensity contain information about the dynamics of the scattering particles. This information can be extracted by constructing a time correlation function (TCF). The TCF is computed using a digital correlator. In the case of dilute dispersions of spherical particles, the TCF provides quick and accurate determination of the translation diffusion coefficient of the particles. Using the Stokes-Einstein equation, the diffusion coefficient can easily be transformed into average particle size provided the viscosity of the suspending medium, its temperature, and refractive index are known.
A conventional apparatus for DLS experiments includes a source of laser light and a transmitting optical arrangement to launch the laser light into an illumination volume of a sample. The apparatus also includes a collecting optical arrangement to coherently collect the scattered laser light from a detection volume in the sample. The overlap of the illumination volume and the detection volume is the scattering volume.
A major problem in DLS systems is optical alignment. The optical arrangements must b e precisely aligned to obtain meaningful data. This is a tedious procedure that unfortunately limits the use of DLS to well-controlled environments such as a laboratory.
The recent use of fiber optics in DLS systems partially addresses the problem of optical alignment. First initiated by Tanaka and Benedek [Appl. Opt., 14, 189 (1975)], fiber optics provide several advantages over conventional optics in DLS systems. Fiber optics are compact, rugged, easy to handle, and portable.
The problem of optical alignment has also been partially re solved by integrating the transmitting and collecting optical arrangements into a single compact housing. This has allowed DLS to be used in areas such as biomedical diagnostics, remote sensing, and on-line process control. For example, Tahaka and Benedek showed that a compact fiber optic probe can be used to measure the velocity of the blood flow inside the human body. Other examples of fiber optic based DLS systems have been reviewed by Macfadyen [Optics and Laser Technology, 22, 175 (1990)].
In designing a DLS system, there are primarily two parameters that must be optimized: sensitivity and spatial coherence. Sensitivity is an indication of how high the scattered intensity would be with a given input laser power. Spatial coherence or signal to noise ratio is an indication of how much of the scattered light contains usable signal. Generally, optimizing one parameter can only be done at the expense of the other parameter. In other words, increased sensitivity can only be achieved by lowering spatial coherence, and vice versa. This relationship occurs because both parameters are controlled by the size of the scattering volume. The larger the scattering volume, the greater the intensity of collected light. However, the larger the scattering volume, the lower the spatial coherence. Therefore, a major design objective in DLS systems is an optimal balance between sensitivity and spatial coherence.
Some DLS systems use monomode optical fibers to transmit light through the system. Such systems can be separated into two groups--lensless probe designs and collimating probe designs. Lensless probe designs do not use lenses to transmit or receive laser light. Consequently, the beams from such systems are divergent. Collimating probe designs, on the other hand, use lenses to produce collimated beams of laser light in the scattering volume.
Lensless probe designs are exclusively used in the backscattering regime. Typically, they consist of a single fiber for transmission and reception of the laser light. Such designs suffer from a very small penetration depth (on the order of a few .mu.m) which is the distance between the probe, specifically the end face of the optical fiber, and the center of the scattering volume. This largely limits its application to the examination of immersible fluids wherein the probe is immersed in the fluid sample to obtain measurements.
Another problem with lensless designs is the heterodyning effect due to the internal reflection at the tip of the fiber. This necessitates a great deal of care in fabrication, and limits its application to scattering volumes containing high concentrations of suspended particles so that the scattered signal is strong enough to overcome the reflected signal.
In a two-fiber lensless probe, two monomode fibers are fixed to a housing to achieve a narrow angle between incident and back-scattered laser light. This increases the penetration depth although the depth is still only on the order of a few millimeters. The lensless probe suffers from low sensitivity and low spatial coherence. As a result, the probe is effective for only a limited range of particle sizes and concentrations. When using the probe with a low-power laser, such as in in vivo diagnostics, the range is still further limited. At greater penetration depths, the lensless probe has even lower sensitivity and spatial coherence.
In collimating probe designs, optical fibers are mated with lenses to produce collimated beams of laser light. In such designs, an end face of a monomode optical fiber is positioned at the Fourier plane (also called focal plane) of the lens to produce a collimated illumination volume. This approach, however, significantly compromises the sensitivity and spatial coherence of the probe.
There are essentially two types of optical fibers commercially available for use in DLS systems. One is multimode fiber and the other is monomode fiber or single-mode fiber. There is also polarization-maintaining fiber but it is generally considered to be a subclass of monomode fiber. All of the early fiber-optic DLS systems use multimode fibers because laser light couples more easily with a multi-mode fiber than with a monomode fiber. Further, until recently, no theoretical study showed any advantage of monomode fiber over multimode fiber in DLS systems. Indeed, multimode fiber collects much more scattered light than monomode fiber. However, multimode fiber has very poor spatial coherence. Thus, additional pinholes or apertures are needed in the optical arrangements to enhance the spatial coherence to an acceptable level.
The use of monomode optical fiber was first explored in Brown, J. Phys. E: Sci. Instrum., 20, 1312 (1987). Brown designed a 90.degree. DLS system using monomode optical fiber and micro lens. An advantage of monomode fiber is that it uniquely transmits only a single, spatially-coherent mode of light. This effectively eliminates the need for pinholes or apertures, as was pointed out by Ricka [Appl. Opt., 32, 2860 (1993)] in his theoretical study of monomode fiber.
Later, a multiangle DLS spectrometer system using monomode optical fiber and a graded index (GRIN) lens was taught in Dhadwal and Chu, Rev. Sci. Instrum., 60, 845 (1989)]. In both Brown, and Dhadwal and Chu, the end face of the monomode fiber is placed at the focal plane, also known as the Fourier plane, of the lens. This results in a well-collimated beam and hence well-collimated scattering volume. According to Brown, this configuration yields maximum spatial coherence. See Brown, U.S. Pat. No. 4,975,237 (using monomode optical fiber) Dhadwal and Chu, on the other hand, emphasize higher scattered intensity at the expense of spatial coherence to provide accurate results. See Chu and Dhadwal, U.S. Pat. No. 4,983,040; and Dhadwal, U.S. Pat. No. 5,155,549. Further, they teach that in some cases, using multimode fiber instead of monomode fiber produces better results.
Wiese and Horn [J. Chem. Phys., 94, 6429 (1991)] teach another backscattering DLS system using a lensless backscattering probe having a monomode optical fiber and a directional coupler. This configuration is reported to work well in studying high concentration samples in which the scattering volume is placed at the tip of the fiber. Dhadwal et al. [Rev. Sci. Instrum., 62, 2963 (1991)]I disclose yet another system using two monomode fibers in a lensless. In these lensless designs, the laser beam launched from the monomode fiber diverges with the numerical aperture of the fiber. This produces an overly large, relatively uncollimated illumination volume. Analogously, the lensless collecting optical arrangement produces an overly large and relatively uncollimated detection volume. The results in an overly large scattering volume.
There are several patents on DLS systems using monomode optical fibers. U.S. Pat. No. 4,975,237 to Brown teaches a DLS system in which an end face of a monomode optical fiber is positioned at the focal plane of a lens. This arrangement uses the Fourier transforming property of the lens. The same Fourier transforming principle is also taught in U.S. Pat. No. 4,983,040 to Chu and Dhadwal in a multiangle spectrometer and in U.S. Pat. No. 5,155,549 to Dhadwal in a backscattering probe. In both patents, the scattering volume is created by crossing two beams or volumes that are collimated.
U.S. Pat. No. 5,155,549 to Dhadwal and U.S. Pat. No. 5,284,149 to Dhadwal and Ansari disclose backscattering DLS probes having monomode optical fibers and no lenses. The fibers create diverging illumination and detection volumes. By angling the end portions of the fibers inward, the resulting scattering volume is somewhat minimized.
In the field of eye diagnostics (e.g., cataractogenesis, uvetis, and diabetic retinopathy) devices using DLS have elaborate instrumentation and bulk optics. Such DLS devices have optical alignment problems, statistical errors in data analysis, high patient radiation exposure and multiple scattering problems associated with mild and severe cataracts and the polydisperse nature of the cataract itself.
Lensless backscatter fiber-optic probes have been used to study cataractogenesis in eye lenses. However, for reasons stated above, the probe must be brought into close and uncomfortable proximity to the corneal surface of the eye. Moreover, it is very difficult to accurately pinpoint a desired location in the eye. This is because both the effective depth of the scattering volume and the maximum thickness of an adult human lens are about 0.5 mm. Further, the expanding incident laser light tends to disadvantageously illuminate the entire lens. Still further, when the probe is moved beyond about 2.5 mm from the eye/air border, backreflection starts to cause a significant amount of distortion in the collected scattered light. This backreflection increases the photon count rate in the detector and reduces the spatial coherence values. Because of these limitations, in-vivo measurements can only be performed in the front part (anterior cortex) of the eye lens. The nucleus of the eye lens, the posterior cortex, and the vitreous body cannot be probed or accessed reliably by the lens-less probe.
Therefore, it has been deemed desirable to develop a DLS system that has high sensitivity and high spatial coherence. Further, it is has been deemed desirable to develop a DLS system that is accurate, compact, easy to manufacture and easy to use.
The present invention contemplates a new and improved laser light scattering apparatus and method that overcomes all of the above noted problems and others and provides integrated transmitting and receiving optical arrangements for accurate characterization of particles size and related information and is simple and economical to manufacture and use.


A system architecture for thwarting denial of service attacks on a victim data center is described. The system includes a first plurality of monitors that monitor network traffic flow through the network. The first plurality of monitors is disposed at a second plurality of points in the network. The system includes a central controller that receives data from the plurality of monitors, over a hardened, redundant network. The central controller analyzes network traffic statistics to identify malicious network traffic. In some embodiments of the system, a gateway device is disposed to pass network packets between the network and the victim site. The gateway is disposed to protect the victim site, and is coupled to the control center by the redundant hardened network.

This invention relates to techniques to thwart network-related denial of service attacks.
In denial of service attacks, an attacker sends a large volume of malicious traffic to a victim. In one approach an attacker, via a computer system connected to the Internet infiltrates one or a plurality of computers at various data centers. Often the attacker will access the Internet through an Internet Service Provider (ISP). The attacker by use of a malicious software program places the plurality of computers at the data centers under its control. When the attacker issues a command to the computers at the data centers, the machines send data out of the data centers at arbitrary times. These computers can simultaneously send large volumes of data over various times to the victim preventing the victim from responding to legitimate traffic.
One type of attack is a transport control protocol (TCP) SYN flood attack. With the transport control protocol (TCP) a connection between two hosts on the network is initiated via a three-way handshake. During a TCP SYN flood attack, an attacker will send many SYN packets to victim.
One approach is described in "Analysis of a denial of service attack on TCP" by Schuba et al. Proceedings of the 1997 IEEE Symposium on Security and Privacy (IEEE Computer Society Press, May 1997). This paper analyzes a network-based denial of service attack for IP (Internet Protocol) based networks. The paper provides an approach for protection against SYN flooding attacks for all connected to the same local area network. The approach recognizes that the attacking site generally will not respond by sending ACK packets to the victim in response to the victim sending corresponding SYN ACK packets.

Thwarting connection-based denial of service attacks


Methods for trimming trees with a machine that includes an elongated boom pivotally connected to the upper portion of a mast for elevational movement with the mast, an inboard rotor and an outboard rotor both rotatably mounted on the boom and a plurality of saws rotatably carried on each of the inboard and outboard rotors for rotation in a generally parallel plane are improved to prevent cuttings from accumulating in the tops of trimmed trees by rotating the inboard rotor and the saws carried thereby counterclockwise and rotating the outboard rotor and the saws carried thereby clockwise. Machines for carrying out the improved methods are disclosed.

1. Field of the Invention
This application relates to tree trimming machines and methods. More particularly, it concerns mobile machines used to top and trim trees, e.g., rows of citrus trees in groves, apple trees in orchards, etc., to maintain then in proper growing condition to produce high fruit yield.
2. Description of the Prior Art
Fruit and nut bearing trees require periodic trimming of their tops and sides in order to maintain them in good growing condition for maximum yield and to assist in harvest of their crop. Hence, a variety of machines have been developed for this purpose as disclosed in the following U.S. patents:
U.S. Pat. No. 2,926,480 PA1 U.S. Pat. No. 2,940,486 PA1 U.S. Pat. No. 3,157,016 PA1 U.S. Pat. No. 3,214,895 PA1 U.S. Pat. No. 3,395,520 PA1 U.S. Pat. No. 3,415,046 PA1 U.S. Pat. No. 3,913,304.
One form of machine made and sold by FMC Corporation that has been widely used for tree trimming is disclosed in U.S. Pat. No. Re. 26,793, the contents of which are incorporated herein by reference. This FMC machine is capable of both height and angular adjustment permitting trees to be cut with a flat top or peaked top. While it is a "single boom" machine on which a pair of rotors that carry a plurality of circular saws are supported, "double boom" machines have been developed and used (see U.S. Pat. No. 3,415,046 supra).
Trees in groves and orchards are conventionally planted in rows with middles (lanes) between them over which machinery needed to work them can be moved. Typically, a tree trimming machine will move along one of these lanes while its boom or booms extend laterally over the trees to allow the rotating saw to cut brush from them. One problem associated with such type operation is removing the cut brush. Thus, the brush has a tendency to fall onto or into the trimmed tree which is unacceptable since, if it is left there, it will diminish crop growth and/or become a source of disease. Hence, tree trimming machines have been provided with additional devices, e.g., resilient brush engaging fingers, designed to convey or force cuttings to move away from the trees during the cutting operation. The present invention provides a unique improvement in prior known tree trimming machines to attain required cut brush removal without need for such additional devices.


Gasketing paper is commonly made by the beater addition process. In the beater addition process a furnish composition is prepared by mixing latex into a fiber slurry which also typically contains one or more fillers. The beater addition process is currently being scrutinized because of environmental concerns. More specifically, conventional lattices used in the beater addition process contain curatives, such as amines, sulfur, and zinc compounds, which are discharged into the environment via the affluent from the process. By practicing the process of this invention gasketing paper can be manufactured by an environmentally sound technique. In one embodiment of this invention gasketing paper is made by beater addition with the latex utilized in the process being comprised of (a) at least one rubber having both pendant blocked isocyanate groups and groups containing at least one active Zerewitinoff hydrogen, (b) at least one emulsifier, and (c) water.

A gasket is an article which is clamped between adjacent faces and acts as a static seal. Depending upon its particular application, a gasket may be required to resist extremely high and/or low temperatures, elevated pressures and/or vacuum, thermal expansion, and various chemicals. The use of gaskets in internal combustion engines is very prevalent. For example, in internal combustion engines gaskets are used to create a seal to keep engine fluids, such as oils, fuels, coolants, within the engine and to keep outside dirt and other contaminants from entering the engine. Gaskets of desired sizes and shapes are often made by stamping them out of gasketing paper.
Gasketing paper is often made by the beater-addition process. The beater-addition process is described in U.S. Pat. No. 2,759,813. In the beater addition process, a slurry of at least one fiber in water is mixed with a rubber latex. This slurry also often contains one or more fillers. The latex in the slurry is precipitated to form a furnish composition. The furnish is then processed into sheet by removing excess water via a cylinder machine, a fourdrinier, or similar processing equipment. Additional water is pressed out of the sheet with vacuum generally being applied to enhance evaporation. The sheet is then further dried in drying ovens or on steam cans. The dried sheet is then generally calendared into gasketing paper having the desired density. Gaskets of the desired shape can then be stamped out of the gasketing paper and cured.
The gasketing paper typically contains curatives, such as amines, sulfur and/or zinc compounds, which are needed to cure conventional rubbers therein. The beater addition process has been criticized from an environmental standpoint because these curatives are released into the environment through the effluent from the process. It would accordingly be desirable to develop a latex of a rubber which can be cured without the need to utilize conventional curatives. Such a rubber composition is disclosed in U.S. patent application Ser. No. 07/315,987, filed on Feb. 27, 1989. Such rubber compositions can be cured (crosslinked) by heating without the need for conventional curatives. Ser. No. 07/315,987 discloses three types of rubber compositions which can be cured without utilizing conventional curatives. The first type of rubber composition described is comprised of (1) at least one rubber having pendant block isocyanate groups bound thereto; and (2) at least one compound which contains at least 2 Zerewitinoff active hydrogens. The second type of rubber composition is comprised of (1) at least one rubber having Zerewitinoff active hydrogens bound thereto; and (2) at least one compound having at least two block isocyanate groups bound thereto. The third type of rubber composition disclosed is comprised of polymer chains having (1) pendant blocked isocyanate groups bound thereto; and (2) Zerewitinoff active hydrogens bound thereto. It is highly preferred for the latices utilized in practicing this invention to contain this "self-curing" type of rubber which has both pendant blocked isocyanate groups and groups containing active Zerewitinoff hydrogen.


Provided is a clutch that is able to not only transmit torque smoothly even when an input shaft and an output shaft significantly differ in relative speed and phase, but also reduce an energy loss during torque transmission. The clutch (10) includes a dog clutch (40) for transmitting forward or reverse torque from the input shaft (11) to the output shaft (12), and a friction clutch (20) for transmitting torque from the input shaft (11) to the output shaft (12) and disposed in parallel with the dog clutch (40), and selectively transmits or interrupts torque between the input shaft (11) and the output shaft (12).

A friction clutch for transmitting torque by using a friction force is known. A vehicle motive power transmission structure disclosed in Patent Literature 1 is such that a friction clutch is disposed between an input shaft and an output shaft in a situation where engine torque is inputted to the input shaft and electric motor torque is inputted to the output shaft.

Clutch and vehicle motive power transmission structure


What is described is an apparatus for intravascular pressure measurement, comprising an elongate body, a first pressure sensor and a centering assembly disposed adjacent the sensor. In one aspect, the elongate body has a uniform diameter from the distal end to the proximal end. In another aspect, the uniform diameter is 0.035 inches or less. In still a further aspect, the elongated body is a catheter having a plurality of reinforcing filaments and the filaments are utilized to electrically connect the sensor to the proximal end.

Heart disease is a serious health condition affecting millions of people worldwide. One major cause of heart disease is the presence of blockages or lesions within the blood vessels that reduce blood flow through the vessels. Traditionally, surgeons have relied on X-ray fluoroscopic (planar) images to show the external shape or silhouette of the blood vessels to guide treatment. Unfortunately, using only X-ray fluoroscopic images lends a great deal of uncertainty about the exact extent and orientation of the lesion responsible for the occlusion, making it difficult to find the exact location of the stenosis for treatment. In addition, X-ray fluoroscopy is an inadequate reassessment tool to evaluate the vessel after surgical treatment.
A currently accepted technique for assessing the severity of a stenosis in a blood vessel, including ischemia-causing lesions, is fractional flow reserve (FFR). FFR is defined as the ratio of the maximal blood flow in a stenotic artery, taken distal to the lesion, to normal maximal flow. Accordingly, to calculate the FFR for a given stenosis, two blood pressure measurements are taken: one measurement distal or downstream to the stenosis and one measurement proximal or upstream to the stenosis. FFR is a calculation of the ratio of the distal pressure measurement relative to the proximal pressure measurement. FFR provides an index of stenosis severity that allows determination as to whether the blockage limits blood flow within the vessel to an extent that treatment is required. The more restrictive the stenosis, the greater the pressure drop across the stenosis, and the lower the resulting FFR. FFR measurements can be used as a decision point for guiding treatment decisions. The normal value of FFR in a healthy vessel is 1.00, while values less than about 0.80 are generally deemed significant and require treatment. Common treatment options include angioplasty, atherectomy, and stenting.
One method of measuring the pressure gradient across a lesion is to use a pressure sensing guidewire that has a pressure sensor embedded within the guidewire itself. A user may initially position the pressure sensor of the guidewire distal to the lesion and measure the distal pressure before drawing the guidewire backwards to reposition the sensor proximal to the lesion to measure the proximal pressure. This method has the disadvantages of inaccurate pressure readings due to drift and increased susceptibility to thermal variations, difficulty maneuvering a guidewire through blockages, high manufacturing costs, and time-consuming repositioning steps (especially in situations involving multiple lesions). Further, pressure-sensing guidewires often suffer from reduced precision and accuracy in making intravascular pressure measurements when compared to larger pressure-sensing devices, such as aortic pressure-sensing catheters.
Another method of measuring the pressure gradient across a lesion is to use a small catheter connected to a blood pressure sensor, which is often contained in a sensor housing associated with the catheter. However, this method can introduce error into the FFR measurement because as the catheter crosses the lesion, the catheter and the sensor housing themselves create additional blockage to blood flow across the lesion and contributes to a lower distal blood pressure than what would be caused by the lesion alone, which may exaggerate the measured pressure gradient across the lesion.
While the existing treatments have been generally adequate for their intended purposes, they have not been entirely satisfactory in all respects. The devices, systems, and associated methods of the present disclosure overcome one or more of the shortcomings of the prior art.

Device, system, and method for assessing intravascular pressure

PHILIPS IMAGE GUIDED THERAPY CORPORATION


The fouling rate of quench systems in acrylonitrile manufacturing processes is reduced by maintaining a low level of highboiling organic compounds in aqueous recycle streams to the quench systems.

This invention relates to the recovery and purification of acrylonitrile made by catalytic ammoxidation of propylene.
In commercial processes for preparation of acrylonitrile from propylene, ammonia, and oxygen (air), the reactor effluent contains, in addition to the desired acrylonitrile product, considerable amounts of by-product hydrogen cyanide, acetonitrile, and other impurities such as succinonitrile and other nitriles. The exact composition of the effluent and the by-products and impurities it contains may vary considerably depending on the ammoxidation reaction conditions and catalyst.
Processes for treating reactor effluents of the type described to separate and recover acrylonitrile product and desired by-products such as hydrogen cyanide and acetonitrile are known. For example, see U.S. Pat. Nos. 3,399,120; 3,433,822; 3,936,360; 4,059,492; 4,166,008; and 4,404,064, the disclosures of which are incorporated herein by reference. Typically, these processes include introducing the reactor effluent into a quench chamber where it is contacted with water (usually containing sulfuric acid to neutralize excess ammonia from the reaction) to cool the effluent and remove some contaminates such as polymers produced in the reactor. Cooled effluent gases from the quench flow to an absorber column where they are contacted with water. The liquid stream from the bottom of the absorber column contains most of the nitriles produced in the reaction and impurities and is sent to an extractive distillation column. The major portion of the acrylonitrile from the extractive distillation column is obtained in the overhead (distillate) from the column while water and impurities constitute the bottom stream from the column. In accordance with practices of the art, the bottom stream is frequently fed to a secondary distillation or stripper column to separate acetonitrile and water in an overhead stream while the secondary column bottoms containing water and various impurities are recycled to the quench column. It was apparently believed that the impurities in the recycle stream were acceptable in the quench system (see, for example, U.S. Pat. No. 3,960,360). The large quantity of quench liquid required by the quench column and waste management considerations make the appropriate use of recycle water an important process consideration. Accordingly, improvements in recycle practices are sought by those skilled in the art.


An automatic back patter includes a main body, a power source, a striking disc, at least one transmitting arm, and at least patter head. The power source, the striking disc, and the transmitting arm (or arms) are installed in the main body, with the transmitting arm connected to the striking disc at one end and connected to the patter head at the other end. The patter head is fitted in an opening provided in an upper wall of the main body. Then when the power source is started, the patter head is moved up and down by the transmitting arm that is moved up and down by rotation of the striking disc rotated by the power source. When the patting head is moved up and down, it protrudes out of the opening of the main body to pat continuously and regularly the body surface of a user, whose blood circulation may be invigorated, preventing the user from getting bedsores.

1. Field of the Invention
This invention relates to an automatic back patter, particularly to one usable for a patient bedridden for a long period of time in order to invigorate blood circulation and to prevent the muscle tissue from gradually dying.
2. Description of the Prior Art
A patient lying in bed for long and hardly possible to turn over his/her body, for example, those suffering stroke, vegetables, those with four limbs paralyzed, and seniors bed-ridden. Such a person is apt to suffer from bad partial blood circulation in the body surface, and if worse, his/her muscle tissue may die, so to speak, getting "bedsores", which often happen to the portions of the body where receives heavy weight, such as the back and the buttocks. In order to avoid such bedsores, those sections of the body have to be regularly patted or massaged and the body has to be often turned over, as shown in FIG. 9. However, such long regular works may be a troublesome, laborious and tiresome task for the family members of a patient, and if a professional nurse is hired for that purpose, the expense may be a large economic burden to a family. Even if a special nurse is hired for a patient, if the nurse has to take care of a few patients at the same time, the nurse may not be able to regularly turn the body of the patient or make patting or massaging at regular time, so the bedsores may not be surely prevented from happening.
3. Description of the Prior Art
There are many kinds of massaging machine and devices, but they are hardly applicable to a patent bed-ridden for a long period of time and difficult to turn over the body.
In view of lessening pains and troubles of a bed-ridden patient and burdens of his/her family and a nurse taking care of the patient, this invention has been devised to offer an automatic back patter that can make regular patting on the back of a patient or any other section of the body. Then the muscle of the back can be massaged to stimulate blood circulation for preventing the muscle tissues from getting dead.