A disk drive system including a disk having a magnetic surface and suppported for rotation on a spindle, a magnetic head being movable relative to the magnetic surface, and a spindle motor for driving the spindle. The motor generates a back-EMF voltage during an emergency condition and switches said back-EMF voltage during said emergency condition. A comparator circuit compares different phases of back-EMF voltage, and a control circuit controls said plurality of switches to supply said back-EMF voltage to direct said head to a stored position.

Magnetic disk storage systems are used widely to provide large volumes of relatively low-cost, computer-accessible memory or storage. A typical disk storage device has a number of disks coded with a suitable magnetic material mounted for rotation on a common spindle and a set of transducer heads carried in pairs on elongated supports for insertion between adjacent disks, the heads of each pair facing in opposite directions to engage opposite faces of the adjacent disk. The support structure is typically coupled to a positioner motor, and the positioner motor typically includes a coil mounted within a magnetic field for linear movement and oriented relative to the disks to move the heads radially over the disk surfaces to thereby enable the head to be positioned over any annular track on the surfaces. In normal operation, the positioner motor, in response to control signals from the computer, positions the transducer heads radially for recording data signals on or retrieving data signals from a pre-selected one of a set of concentric recording tracks on the disks.
The transducer heads are supported above the disk surfaces by a film of air to prevent contact therebetween which might thereby otherwise damage one or both members. The heads are typically designed to actually fly above the disk recording surfaces of heights less than 50 microinches. Irreparable damage can result from an electrical power failure which slows the disk and allows the head to settle into contact with the disk surfaces. As a result, it is imperative that the heads be withdrawn from the vicinity of the disk if the disk rotational speed is substantially reduced. It is also important in removable media disk drives to ensure that the heads are removed from the vicinity of the disk surfaces in event of power failure so that the disk can be removed from the system without damage to the heads.
The process of removing the heads from the disks in an emergency situation is referred to as an "emergency unload procedure" and requires the heads to be moved radially toward the disk's outer tracks axially away from the disk surfaces (OD). Although loss of power is probably the primary reason for initiating an emergency unload procedure, the procedure is typically also initiated when disk speed does not remain within tolerances, positional error is detected, or write circuits faults that could affect the stored data are detected.
Basically, all modern disk drives incorporate some assistance for executing an emergency unload procedure in order to avoid the loss of data and prevent disk and/or head damage. In typical prior art, emergency unload systems, a capacitor is charged by the drive power supply during normal operation. During the detection of an emergency condition, a relay or equivalent switching means switches the capacitor across the positional coil terminals to provide the electromagnetic force necessary to move the.head support structure across the disk surfaces. Upon approaching the disk's outer edge, the head support structure encounters a mechanical ramp which imparts an axial force to the support structure, thus unloading the heads from the disk.
FIG. 1 illustrates a prior art system, which includes a three-phase spindle motor 130 which drives the disks, and a drive circuit 116, which is used to control the commutation of motor 130 during normal operation. As illustrated in FIG. 1, the drive circuit 116 includes a plurality of FET circuits which have a inherent set of diodes numbered 110, 112 and 114 across the source to drain of each FET. In addition, to connect to the VCM (voice control motor) 120, a set of Schottky diodes, numbered 102, 104 and 106, connect with capacitor 100, which is connected in parallel with the VCM motor 120. In operation, the back-EMF voltage from motor 130 is fed to Schottky diodes 102, 104 and 106, respectively, and from the Schottky diodes 102, 104 and 106, the back-EMF voltage is fed to capacitor 100. The three Schottky diodes 102, 104 and 106 perform passive rectification to allow the back-EMF voltage to charge the capacitor 100, and this charge stored on capacitor 100 is used to power the VCM motor 120 during emergency conditions.
However, the voltage produced by the motor 130 is typically very low on the order of 3.5 volts peak-to-peak in mobile servo application. During emergency conditions, the back-EMF voltage is rectified by the beforementioned diodes, and consequently, as a result of the rectification, the back-EMF voltage is reduced to approximately 2.2 volts peak-to-peak. Further losses occur as a result of the voltage drops across two diodes in series on the VCM retract current path, resulting in only approximately 0.7 or 0.8 voltages being applied to the VCM motor 120. As a consequence, the current available to move the heads across the disk surface and out onto the ramp is significantly reduced. A large amount of current is required to park the head on the ramp and this is not sufficient for any true ramp load applications.
FIG. 2 illustrates another circuit used to convert the back-EMF voltage to energize the VCM motor 220. This circuit includes a set of bipolar transistors 202, 204, 206, 208, 210 and 212 that are used to control the back-EMF current. However, this circuit suffers from two additional defects. First, depending upon a particular design, the finite value of V.sub.BE,ON may vary significantly with process, thus resulting in a deadband where no rectification occurs and no back-EMF voltage is available. Additionally, the circuit in FIG. 2 requires a discrete logic circuit 222 to control the bases of transistors 202, 204, 206, 208 and 212. The bipolar circuits are not compatible with CMOS process, and, as a consequence, the circuit must be external to the circuit (assuming a CMOS circuit) used to drive the motor. Thus, consequently, there is a need for a circuit which is economical in terms of current to operate and is highly accurate.

Spindle motor back-EMF synchronous rectifier


An I.sup.2 L circuit for superimposing audio-frequency electrical signals in an electronic organ is provided. With each current unit of audio-frequency to be superimposed a double-collector I.sup.2 L transistor is associated, and each key is coordinated to an injector, the current of which is switched by said key. In addition to the collecting bars into which said current units are fed, there is provided a separate collecting bar into which the non-audio-frequency collector currents of double collector transistors are fed, each of which being coordinated to each injector. A bounce effect is avoided by subtracting the signal of the separate collecting bar from the signals on the other collecting bars.

1. Field of the Invention
The present invention deals with an integrated circuit for an electronic organ and, more particularly, to an I.sup.2 L circuit for superimposing audiofrequency electrical signals linearly, and to obtain them at certain outputs either as a voltage signal or as a current signal.
2. Description of the Prior Art
With the aid of master oscillators, voltage or current units may be formed and then superimposed. These units are not fixed absolutely in their amplitude, but may rise or drop to certain values either applied to or produced at the key contact, so that it is possible to achieve certain effects such as "sustain", "percussion", etc. Relative thereto, reference is made to the German technical journal "Funk-Technik" (1972), No. 19, pp. 695 to 699 and No. 20, pp. 737 to 784.
Superimposing the units of certain sound groups in accordance with the organizational scheme of the electronic organ, independently of the aforementioned possibilities of achieving special effects, should moreover be without interactions upon the amplitudes up to a maximum value. These interactions occur above all when actuating the keys and are noticed as a clicking noise ("bounce"), and are due to direct voltage or direct current steps, as has been described in the German technical journal "Funk-Technik" (1972), No. 17, pp. 630 to 632.

Integrated I.sup.2 L circuit for superimposing audio-frequency electrical signals of an electronic organ


A preferably hermetic motor-compressor unit comprises a usual drive shaft operated by a known electric motor and acting on a compressor section (1) for a fluid, for example a refrigerant fluid, comprising a piston (3) associated with a connecting rod (2) operated by the said shaft, said piston (3) moving within the bore (23) of a corresponding cylinder (4) in which it compresses said fluid. With the connecting rod (2) there are associated means (11) arranged to engage with counter-means (13) associated with the piston (3) so as to connect this latter to the connecting rod (2), retention means (20) being provided to maintain the engagement between said means and counter-means.

This invention relates to a preferably hermetic motor-compressor unit of the type comprising a usual drive shaft operated by a known electric motor and acting on a compressor section for a fluid, for example a refrigerant fluid, comprising a piston associated with a connecting rod operated by the aforesaid shaft, said piston moving within the bore of a corresponding cylinder in which it compresses said fluid.
In a motor-compressor unit of the aforesaid type the connecting rod has to be connected to the compressor section. This means that known machining work has to be carried out on the piston, resulting in considerable construction time and cost for this section, which are reflected in the overall manufacturing time and cost of the motor-compressor unit.
In addition, in hermetic motor-compressor units the pistons of the compressor sections are not provided with piston rings for reasons related to the section construction cost, noise and the power dissipated by friction, in that the cost, noise and power dissipation all increase.

Compressor section in an easily assembled motor-compressor unit


An apparatus for shot peening blade mounting areas on a disc of a rotor includes a peening nozzle unit which streams shot peening media along a longitudinal axis. The unit includes a nozzle outlet which extends at least partially in a circumferential direction of the unit, and a deflection arrangement with a deflection area for the media. The deflection area is at least partially cone or half-hyperboloid shaped, such that the media passes the nozzle outlet over an angle range in circumferential direction after being deflected by the deflection arrangement. A method for shot peening the blade mounting areas positions the unit in a slot profile of a blade mounting area, and guides the unit along the contour of the slot profile with the nozzle outlet facing the contour of the slot profile to approximately uniformly peen the contour of the slot profile.

Rotors of gas turbines, in particular aircraft gas turbines, comprising a rotor disc and blades arranged in circumferential direction around the disc are widely known from practical experience. Typical blades are inserted with a dovetail shaped blade root into also dovetail shaped blade mounting areas on the disc. The dovetail of a turbine blade typically includes corresponding pairs of upper and lower dovetail lobes or tangs in a fir tree configuration. Correspondingly, the perimeter of the rotor disk includes a row of axial dovetail slots defined between corresponding disk posts having complementary upper and lower supporting lobes or tangs.
In order to make the blade mounting areas durable and failsafe it is known to strain-harden the surface of the blade mounting areas by shot peening. With this method, a for example ball-shaped shot peening media is blasted or peened, respectively, with high velocity against the surface of the blade mounting area. Said method allows the improving of the mechanical features of the component and the inducing of inherent compressive stress into the surface of the component such that the danger of crack formation and propagation in the component is reduced, and the fatigue strength and the life time of the blade mounting areas are increased.
Due to the contour of the blade mounting area profile like a dovetail or a fir-tree profile, there is a very limited accessibility for a shot peening device. Currently, shot peening of blade mounting areas is performed by using nozzles which are fitted on specific retaining fixtures and peen the blade mounting areas from the outside with a shower-like media stream. During the peening, the peening stream of the nozzles is directed substantially perpendicular to a slot bottom of the blade mounting area. Due to the unique contour shape of the blade mounting area, several areas are hit very well by the peening stream, however some very poorly. An area of difficult accessibility are the pressure flanks of the blade mounting area which are hit by the shot peening media in particular via rebounds from the slot bottom. Therefore, peening with standard outside peening nozzles from outside the component results in a non-uniform peening treatment since the slot bottom and the pressure flange are unequally exposed to the peening stream. In particular for dovetail profiles the unequal alignment of the pressure flange and the slot bottom against the peening stream is a determining factor.
For providing sufficient strengthening of the pressure flanks with shot peening, it is known to peen the slot bottom very intensively, so that the pressure flanks are peened by the rebounds from the slot bottom with a desired intensity. However, this method may result in a damaging of the slot bottom. Further, no uniform shot peening treatment of the whole blade mounting area in terms of peening intensity, peening coverage, originated surface roughness and residual stresses in the component surface is possible due to the unfavorable hit angle of the peening stream onto the blade mounting area surface.
From DE 10 2008 010 847 A1 it is known to shot peen blades of blade integrated discs (blisks) with a dual-nozzle unit from a suction side and a pressure side of the blade in one step. For making that possible each peening nozzle has a planar deflection area arranged with an angle to a longitudinal axis of each peening nozzle which redirects peening shot media from moving mainly along the longitudinal axis to a direction essentially vertically to the longitudinal axis. Therefore, the peening shot media can be shot from both sides simultaneous against the both sides of the surface of the blade.
Ultra-Sonic-Peening is another possible method to strengthen the surface of a blade mounting area. With this method, the treated component surface and a chamber create a hermetically sealed area where an Ultra-Sonic-Peening source imparts a small volume media stream on the part surface randomly, thereby strengthening it. It is a disadvantage of this method that material damages may occur due to the rather big size of the peening elements which may cause deformations in areas with thin material. Further, applying this method is quite costly as for each type of contour a separate chamber is required.

Apparatus and method for shot peening of blade mounting areas on a rotor arrangement disc


A method controls state changes of a drivetrain of a vehicle connecting at least one heat engine and/or one electric motor to the wheels of the vehicle via a transmission, providing the transfer of torque from the heat engine and/or from the electric motor to the wheels in one or more gear ratios. The authorization to switch from a current state to a target state depends on reducing an acceleration of the vehicle in an intermediate state causing a lower acceleration of the vehicle during the transition between the current state and the target state.

The present invention concerns the control strategies implemented in powertrain computation units.
It finds a preferred but non-limiting application to powertrains comprising at least one internal combustion engine and one electrical traction machine.
To be more precise, an object of this invention is a method for controlling state changes of a vehicle drivetrain connecting at least one internal combustion engine and/or one electrical machine to the wheels of the vehicle via a transmission that transfers torque from the internal combustion engine and/or the electrical machine to the wheels in accordance with one or more gear ratios.
These states are defined by various combinations of couplers and reducers to transfer torque from the internal combustion engine and/or the electrical machine to the wheels in accordance with one or more gear ratios. The state of a drivetrain can therefore be defined by a combination of solicited couplers and reducers. The state target of the drivetrain aims to optimize the operating point of the powertrain. In an internal combustion powertrain, a drivetrain state can simply be defined by the engagement of a ratio and the position (open or closed) of an input clutch between the engine and the gearbox. On a hybrid powertrain, its definition is necessarily more complex because it has to integrate the state of one or more electrical machines that are able to propel the vehicle via the same axle as the internal combustion engine or via another axle.
On a hybrid vehicle, the acoustic behavior of the vehicle depends, inter alia, on the distribution between electrical power and internal combustion power. Harshness, linked to the performance of the powertrain, also depends on the state of charge of the traction battery, as only the internal combustion engine is usable when it is discharged. Finally, energy management laws that determine the distribution of power in compliance with consumption and pollution reduction constraints at each operating point. Similarly, a classification of the optimum states of the drivetrain must also take account of the state of charge of the battery.
The drivetrains of a internal combustion vehicle and a hybrid vehicle also differ considerably:                on a hybrid vehicle, the internal combustion engine is not the only source of motor power;        for the same power demand, there is a plurality of possible combinations of the power delivered by the internal combustion engine and that delivered by the electric motor(s);        depending on the technical definition envisaged, power from the electrical machine either passes through the transmission or does not;        the static and dynamic max/min limitations of the hybrid powertrain depend on the state of charge of the battery and so vary over time;        the electric or ZEV (zero emission vehicle) traction mode combines one or more specific states of the drivetrain by the same token as the discrete ratios of the internal combustion engine.
Generally speaking, acoustic phenomena, harshness and likewise the consumption and pollution reduction level address particular constraints on a hybrid vehicle. For the same operating point (speed, motor power), the acoustic level of the powertrain depends on the distribution between electric power and internal combustion power, the electric motor being quieter.
Harshness, which is linked to the performance of the powertrain, depends on the state of charge of the battery. If it is charged, it is possible to use simultaneously the power delivered by the electric motor and by the internal combustion engine. If it is discharged, the overall power available is reduced as the only source of energy available is the internal combustion engine, with a possible reduction of performance. Finally, the consumption and pollution reduction requirements are taken into account in energy management laws that in each hybrid state establish the distribution between the power delivered by the internal combustion engine and that delivered by the electrical machines as a function of the state of charge of the battery.
Moreover, depending on the type of hybrid architecture, the sources of motor power can be installed in the vehicle in various configurations. For example, the electrical machine(s) are associated with the rear wheels, the crankshaft, the secondary shaft of the gearbox, etc. However, the states of the drivetrain of any hybrid vehicle are defined as combinations of the traction units via or not via a transmission with a plurality of ratios. Two target states X and Y can therefore be arrived at in different ways from a current drivetrain state Z. The state changes result from different mechanical changes in the transmission, for example:                coupling the electrical machine without changing ratio for the internal combustion engine,        changing the ratio of the internal combustion engine with the ratio of the electrical machine being maintained,        changing the ratio of the electrical machine without internal combustion engine, etc.
Accordingly, a change from a current state Z can proceed with total interruption of the torque at the wheel, a reduction of the level of torque at the wheel or else with no reduction of the level of torque, depending on the target states X or Y, or in accordance with mechanical changes effected by the transmission. Through significant unanticipated reductions of acceleration, reductions or interruptions of torque at the wheel during changes of state are negatively perceived in terms of harshness by the driver and his passengers and degrade performance, such as the "brio" of the vehicle.
The problem is encountered on a hybrid transmission as described in the publication WO2012131259, for example.
This problem is illustrated in the following way in FIG. 1, in which are shown maximum acceleration curves for different kinematic modes of the transmission. If it is considered that at the operating point 1 in the diagram the current state of the drivetrain is an electric ratio termed ZEV1 and that the vehicle has reached its maximum speed in that state, the transmission must switch to another drivetrain state addressing the harshness constraints associated with the point 1 but also the energy optimization of the vehicle. From the point 1, the states termed HYB23, TH2, HYB33 and ZEV3 respectively corresponding to a first hybrid ratio, an internal combustion ratio, a second hybrid ratio and another electric ratio are permissible from the harshness point of view. However, once established they offer different services. Moreover, the changes to HYB23 and TH2 can be achieved without interruption or reduction of the acceleration of the vehicle, whereas the changes to ZEV3 and HYB33 result in a significant reduction in the acceleration of the vehicle because producing those states involves a passage through the neutral state of the transmission involving total interruption of the torque at the wheels. If an energy optimization criterion calls for the ZEV3 or HYB33 state, the service of changing to one of those states will be degraded by the interruption in torque whereas a change to the other two drivetrain states would offer a better client service and better performance of the vehicle.

Method for controlling state changes of a drivetrain


A method for the production of water soluble polyaluminosilicate microgels by the reaction of dilute polysilicic acid solutions with dilute solutions of alkali metal aluminates.

It is known that amorphorus, water insoluble polyaluminosilicates can be formed by the reaction of alkali metal polysilicates with alkali metal aluminates. Such polyaluminosilicates or synthetic zeolites have found use as catalysts, catalyst supports and ion exchange materials. Also, it is known that the particles in colloidal silica sols can be surface aluminated by aluminate ions to form a coating of polyaluminosilicate as disclosed in the book "The Chemistry of Silica" by Ralph K. Iler, John Wiley & Sons, NY, 1979, pp. 407-410.
U.S. Pat. No. 4,213,950 discloses an improved process for the preparation of amorphous, water insoluble polyaluminosilicates by the reaction of alkali metal aluminates with aqueous polysilicic acid at pH 2-4. The disclosure stresses the use of true solutions of polysilicic acid not appreciably crosslinked and distinguished from colloidal solutions, suspensions, dispersions and gels.
The present invention is concerned with the preparation of new water soluble polyaluminosilicate microgels having unique properties and characteristics. The new materials are formed over a wide pH range of 2-10.5 by the reaction of aqueous solutions of partially gelled polysilicic acid and an aqueous solution of an aluminum salt, preferably an alkali metal aluminate, followed by dilution of the reaction mix before gelation has occurred in order to stabilize the polyaluminosilicate microgels in an active form. Alternatively, the water soluble polyaluminosilicate microgels may be produced by dilution of the polysilicic acid stock before mixing with the alkali metal aluminate. The water soluble polyaluminosilicates so produced are distinct from the amorphous polyaluminosilicates and polyaluminosilicate coated colloidal silicas of the prior art in that they have a very high surface area, typically 1000 meter.sup.2 /gram (m.sup.2 /g) or greater and surprisingly a very high surface acidity, typically 1 milliequivalent/gram (meq/g) or greater. The alumina/silica mole ratio or content is generally greater than about 1/100 and preferably between about 1/25 and 1/4. Their physical structure is believed to consist essentially of aggregates of very small particles of silica, surface aluminated, formed into chains and crosslinked into three-dimensional networks or microgels. Some colloidal silica and colloidal alumina particles may be present with the polyaluminosilicate microgels.
The polyaluminosilicates of this invention are formed by the reaction of polysilicic acid with an aluminum salt, preferably an alkali metal aluminate. They consist of aggregates of very small particles having a high surface area, typically about 1000 meters.sup.2 /gram (m.sup.2 /g) or greater and an alumina/silica mole ratio or content greater than about 1/100 and preferably between about 1/25 and 1/4. Their physical structure is believed to form particle chains and three dimensional networks.
The polyaluminosilicates thus formed provide improved operating benefits over the aluminated colloidal silicas of the prior art in papermaking, for example. Such commercial aluminated colloidal silicas used in papermaking consist of larger, non-aggregated particles with a surface area of about 500-550 m.sup.2 /g, a surface acidity of 0.66 meq/g or less, and an alumina/silica mole content of about 1/60.
The water soluble polyaluminosilicates of this invention are believed to derive their structure from the polysilicic acid stock formed initially by an appropriate deionization or acidification of a dilute alkali metal polysilicate, for example Na.sub.2 O.3.2SiO.sub.2. Such polysilicic acid stock, also known as "active silica" consists, according to Iler in the above cited text, pp. 174 and 301-303, of very small 1-2 nanometer (nm) primary particles which are aggregated into chains and three dimensional networks. Such networks or microgels, when converted to aluminosilicates by reaction with sodium aluminate exhibit a considerably greater efficiency in flocculating fiber and filler fines than larger non-aggregated aluminated silica particles particularly when employed with a cationic polymer, such as cationic starch, cationic guar or cationic polyacrylamide. The greater efficiency in flocculation is believed to result from both the increased effectiveness of the microgel structure in locking together or bridging pulp and filler fines and also from the high surface acidity more effectively completing charge neutralization reaction with the cationic components.
The water soluble polyaluminosilicates have a wide range of application to different papermaking stocks including those containing bleached kraft pulp, groundwood pulp and thermomechanical pulp. They may also be used for the clarification of white waters and the recovery of pulp and filler components. They function well under both acid and alkaline papermaking conditions, that is, over a pH range of about 4-9.
U.S. Pat. No. 2,217,466 describes the early use of polysilicic acid or active silica as a coagulant aid in the treatment of raw water. The article "Activated Silica, a New Chemical Engineering Tool" by Merrill and Bolton, Chem. Eng. Progress 1 (1947), 27, summarizes the development and application of anionic active silica and mentions its use as a coagulant for paper mill white water and as a retention aid for fiber and filler fines when added to the head box of a paper machine. No mention is made of the co-use of anionic active silica together with cationic polymers.
U.S. Pat. Nos. 3,224,927 and 3,253,978 disclose the co-use of cationic starch together with anionic colloidal silica as a binding agent for inorganic fibers in refractory fiber bonding applications. The quantities of colloidal silica used are considerably larger than in papermaking applications, that is, 10-20 weight percent (wt. %) of the product for fiber bonding versus about 1 wt. % of the product for paper applications. Also, in fiber binding, conditions leading to flocculation are to be avoided whereas in papermaking, flocculation is a desired result of the additions.
U.S. Pat. No. 4,388,150 discloses a binder composition comprising colloidal silicic acid and cationic starch for addition to papermaking stock to improve retention of stock components or for addition to the white water to reduce pollution problems and to recover stock component values.
International Patent Publication WO86/00100 extends the application of colloidal silicas in papermaking to more acid conditions by describing the co-use of aluminated colloidal silica with cationic starches and cationic guars. Alumination provides stronger acid sites on the surface of the colloidal silica. As a consequence, anionic charge is maintained well into the acid range. The preferred compositions are those containing non-aggregated silica particles of relatively large 5-6nm diameter, low surface area of 500 m.sup.2 /g and an alumina/silica mole content of about 1/60.
International Patent Publication WO86/05826 describes the co-use of the above aluminated colloidal silica and cationic polyacrylamides in papermaking.


A surgical fastener clip for proximating tissue, the clip providing an undeflected state in which the clip comprises a center portion, a first leg, and a second leg. The center portion has a perimeter defining a circle-like shape. The legs project outwardly relative to the perimeter from a point of departure to a tip. Extension of each of the legs relative to the perimeter defines an identical wind direction that is either clockwise or counterclockwise. The clip optionally includes a linear cross-member extending across the perimeter. The surgical clip can be formed by a wire that is partially wound onto itself in a spiral-like fashion, with the center portion and the legs being co-planar in the undeflected state. During use, the clip is rotated, drawing tissue into the center portion. Systems incorporating the clip are also provided.

The present disclosure relates generally to apparatus and methods for surgically proximating tissue, such as in closing a patent foramen ovale or other tissue defect.
The need to surgically proximate and attach segments of tissue arises under a plethora of different circumstances. Tissue defects, such as wounds, are one such example. Treatment of a skin surface wound typically entails suturing edges of the wound together. In many instances, however, the tissue defect to be treated is internally located, and thus not readily accessible by a surgeon otherwise attempting to utilize a conventional suture thread to effectuate repair of the defect. Access to internal tissue defects of these types through invasive surgery introduces a high level of risk that can result in serious complications for the patient, especially where the tissue defect is located at or near a vital organ. One example of an internal tissue defect of this type is a patent foramen ovale ("PFO") that can occur between the left and right atria of the heart.
By way of reference, during development of a fetus in utero, most of the fetus' circulation is shunted away from the lungs through vessels or foramens that are open during fetal life. Normally, these specialized vessels and foramens will close shortly after birth. One such opening is known as the foramen ovale that allows blood to pass directly from the right atrium to the left atrium, thus bypassing the lungs. Following birth, and with establishment of pulmonary circulation, the increased left atrial blood flow and pressure results in the functional closure of the foramen ovale, followed by formation of an anatomical seal with continued development of the heart.
In some instances, the foramen ovale fails to entirely close. This condition, known as PFO, may allow blood to continue to shunt between the left and right atria, posing potentially serious health risks. Other septal tissue defects can also occur and require treatment.
Invasive surgical procedures can be performed to address the septal tissue defects described above, as well as multiple other internal tissue defects. Alternatively, less invasive procedures, such as catheter-based procedures, have been suggested. In the context of PFO treatment, for example, expandable umbrella- or disk-like devices are delivered, via catheter, into the heart. Generally, the device is inserted through the natural opening of the defect, and the expandable structures are deployed to secure or bring together tissue segments surrounding the defect.
Alternatively, other internal tissue defect repair and/or tissue proximation techniques have been suggested in which a clip formed from a super elastic material is provided. The clip is self-transitionable from a deflected state in which the clip (or segments thereof) is at least somewhat linear, to an undeflected state in which the clip has a coiled curvature, thereby drawing opposing ends of the clip more closely to one another. During use, the clip is deployed, in the deflected state, to the defect site via a catheter or other minimally invasive apparatus. Upon deployment from the delivery tool, the clip reverts to the undeflected state or shape, with opposing ends or tips of the clip piercing through the tissue segments, pulling or proximating the segments into contact with one another. For example U.S. Pat. No. 6,776,784 describes that, in repairing a PFO, the clip ends are pierced through septum wall segments. The clip is then allowed to self-transition toward its natural or undeflected state (W-shape). This action, in turn, draws the tissue segments toward one another, serving to at least partially close the PFO. While viable, suggested clip configurations, and related applications, may not provide consistent, long-term closure of the defect. Similar concerns may also arise in the context of other tissue proximation or plication procedures, such as anastomosis, etc.
In light of the above, a need exists for improved devices, systems, and methods for surgically proximating tissue, for example closing tissue defects such as a PFO or other internal tissue defect.

Surgical fastening clips, systems and methods for proximating tissue


This invention generates a digital document by applying character recognition to character images in a document image, and rendering the character recognition result on the document image in a transparent color. This digital document allows to specify a part corresponding to a search keyword on the document image upon conducting a search. When this digital document is generated, it includes a description required to use glyph data (font data) of a simple character shape commonly to a plurality of character types as font data used upon rendering the character recognition result. Therefore, even when the digital document needs to save font data, an increase in file size can be minimized. Also, by rendering using a simple character shape, the data size of the font data itself can be reduced.

In recent years, since scanners and large-capacity storage devices such as hard disks and the like have prevailed, documents that have been saved as paper are scanned and saved as digital documents. In this case, image data obtained by scanning a paper document undergoes character recognition processing to read text information described in that document, and the text information is saved in association with the image. The user can search digital documents associated with text information using search keywords. In order to search for a desired document fast from large quantities of saved document groups in this way, it is important to allow a keyword search even for scan images.
For example, Japanese Patent Laid-Open No. 2000-322417 describes the following technique. That is, when the user searches for a digital document associated with text information using search keywords, text parts that describe the search keywords on that document image are highlighted to be identifiable for the user. Since the text parts corresponding to the search keywords are highlighted, if the document includes a plurality of description parts of identical keywords, the user can efficiently identify the description parts by switching page images.
On the other hand, a technique that embeds results of character recognition processing in an image file as transparent text (character codes designated with a transparent color as a rendering color) and saving the image file in a PDF (Portable Document Format) format is also available. Upon displaying a PDF file generated in this way, transparent text is rendered on character images in a document image. Therefore, upon conducting a keyword search, transparent text is found, but the user cannot see the transparent text itself, and it seems as if an image were found. In this manner, an image which is searchable using search keywords can be rendered based on a file of a format described using a page description language that allows to render an image and text.
Rendering of text in a digital document using a page description language such as PDF, SVG, or the like requires character shape information of each character, i.e., glyph of font data. However, since font data normally has a large size, it is a common practice not to store font data in a digital document and to only designate font types in the digital document. In this way, an application can render text data using fonts installed in a personal computer.
On the other hand, it is often desired to store font data in a digital document. For example, when a digital document generated by a document generation application is to be opened by another personal computer, if font data used in that digital document are not installed in the personal computer, the digital document cannot be opened accurately. In other words, even when a personal computer or application in which no designated font data are installed reproduces a digital document, if font data themselves are stored in the digital document, that digital document can be accurately reproduced.
In some cases, it is desired to store font data used to render characters in a digital document as an indispensable condition depending on use applications. For example, as for files which are to be saved for long terms, fonts installed as defaults may be changed due to a change in OS after an elapse of a long period of time. Hence, it is desired to store font data as an indispensable format.
Some formats have an indispensable condition to store font data in a digital document. For example, in an XPS (XML Paper Specification) format, font data need to be saved together upon saving text data.
However, when font data are stored in a digital document, the size of the digital document itself increases. When the file size increases, it takes much time to transmit a digital document via a network, or a large storage size is required to store the document.
In this manner, in a digital document of a file format that renders characters using font data stored in the digital document, it is desired to prevent the file size from increasing. Especially, when a scan image, text data as a result of character recognition result, and font data used to render text are stored together in a digital document, it is desired to prevent an increase in file size. When font data need to be stored in a digital document due to restrictions of a format, system, and the like, an increase in file size often readily poses a problem.

Image processing apparatus, image processing method, and computer program


A rotary screw compressor for oil-free air, wherein at least one of the shaft journals (11) of the rotors (10) has a seal arrangement between the rotor (10d) and an oil-lubricated bearing (12). The seal arrangement includes at least three frictionless seals (13, 14, 15) separated by annular chambers (16,17). The outermost annular chamber (17) is connected to a source of pressurized air through a supply channel (19) for supplying blocking air to the seal, and another (16) of the annular chambers communicates with a withdrawal channel (18).

The present invention relates to a rotary screw compressor for oil-free air provided with inlet channel means and outlet channel means and having at least one compression stage, each stage including at least one rotor with at least one shaft journal mounted in oil-lubricated bearing means, which shaft journal is provided with seal means between the rotor and the bearing means, which seal means include at least three frictionless seal means surrounding the shaft journal and a plurality of annular chambers surrounding the shaft journal, which frictionless seal means and annular chambers are arranged in an alternating sequence along the shaft journal.
In such compressors handling oil-free air an effective seal between the working space and the bearings is necessary in order to avoid that oil-contaminated air from the bearing housing mixes with the compressed air which can be dry or contain water. The use of direct contact mechanical seals for that purpose results in high friction losses. This is avoided with the type of seal arrangement mentioned above where frictionless seals are used together with a blocking gas, e.g. air.
Seals of this type are disclosed in U.S. Pat. No. 3,975,123 and FR-A-2 569 780.
In U.S. 3,975,123 the seal arrangement has four frictionless seals with three annular chambers between them. Blocking air is supplied to the intermediate annular chamber of the seal and flows outward towards the outermost annular chamber, from which it is withdrawn together with oil leaking from oil-lubricated bearing means. The innermost annular chamber is inactive at full load and connected to inlet pressure at part load for supply of air.
In FR-A-2 569 780 a similar seal device is applied to a two stage air compressor, but in this case only two annular chambers are present. Also in this disclosure the supply and withdrawal of blocking air is such that the blocking air flows in the outward direction.
The relative localisation of the supply and withdrawal of the blocking air in the known devices has the consequence that oil-contaminated air from the roller bearings leaks to the withdrawal channel where it is mixed with the blocking air and leaking air from the compression stage. This causes a problem in that the withdrawn air has to be purified if it is led to the compressor inlet or to the ambient atmosphere.
The object of the present invention is to attain a seal arrangement of the kind in question in which the above described problem is overcome.


The present invention involves the use of photosensitizers to provide antibacterial surfaces on consumer and industrial items. This approach avoids the used of chemicals and solutions that may be toxic. The inventions also avoids the use of chemical compositions that might form degradation products which may be unacceptable to healthy persons or irritating to persons who may have allergies or are otherwise sensitized. According to the invention, photosensitizers with specific properties and specific design features are selected to make practical use of photosensitizers in the consumer and industrial market place. It is important to select a photosensitizer with an activation spectrum that is matched to the environmental conditions under which the surface to be protected is required to exhibit its antimicrobial properties. This means that the illumination energy and intensity levels expected need to yield enough singlet oxygen to destroy the targeted microbes. It is also possible to select photosensitizers that are activated only by wavelengths prominently present in certain illumination lamps, such as those lamps commonly present in a laboratories, medical offices, pharmacies and food service areas, thereby making the surfaces antimicrobial only on demand when the illumination lamps are turned on.

1. Field of the Invention
The present invention relates to products and methods to provide common surfaces with antimicrobial properties to fight bacteria, viruses and fungi.
2. Invention Disclosure Statement
Surfaces of many consumer goods and industrial items are regularly populated by bacteria, viruses and fungi, which can produce health hazards. Cleaning and disinfecting these common surfaces is an everyday hygienic process. Cleaning and disinfecting do not always yield satisfactory results, since many microbes have increasingly become resistant to many of the agents currently being used. Chemical compositions used to disinfect surfaces often have a broad non-specific action and may be health risks to people with allergies or chemical sensitivities.
U.S. Pat. No. 4,532,269 describes a terpolymer that is used as an antimicrobial paint for ships. The coating slowly erodes to produce a highly toxic compound that keeps the paint antimicrobially active. Coatings of this type will lose their action when the active ingredient in the paint eventually migrates to an ineffective level. The toxic compounds created by this invention make it impractical for use in consumer goods or common industrial items.
U.S. Pat. No. 5,534,346 describes an attachable thin film prophylactic barrier used to prevent the spread of infectious disease during medical procedures. The invention is visually transparent or translucent plastic sheet with a pressure sensitive adhesive back. The described invention is a physical barrier and does not have any antimicrobial properties.
U.S. Pat. No. 5,967,714 describes a process for the preparation of antimicrobial polymer surfaces wherein tert-butylaminoethyl methacrylate is graft copolymerized with an aliphatically unsaturated monomer on a polymer substrate. The substrates surface is activated by methods such as UV radiation before the graft polymerization takes place. The described invention is limited to polymer substrates, and antimicrobial protection is only provided at the time the product is manufactured. The invention does not describe how to provide antimicrobial properties to a previously manufactured item.
U.S. Pat. No. 6,214,901 describes a composition for coating a medical device with bioactive agent in a manner that permits the coating to release the bioactive agent over time when implanted in vivo. The described coating composition is particularly adapted for use with devices that undergo significant flexion or expansion in their use. Covering consumer items with the described bioactive agent coatings is not practical since it can interfere with the appearance and utility of the items to be protected.
U.S. Pat. No. 6,080,490 describes an actively sterile surface for a substrate in a biologically dynamic environment. The described invention consists of an antimicrobial element in combination with an electrochemically nobler element that forms multitudinous galvanic cells with biological fluids to release the antimicrobial elements at the target site. Since most commercial and industrial items do not contact biological fluids, use of the described invention to protect such surfaces is not feasible.
U.S. Pat. No. 5,534,346 describes an attachable thin film prophylactic barrier used to prevent the spread of infectious disease during medical procedures. The invention is visually transparent or translucent plastic sheet with a pressure sensitive adhesive back. The described invention is a physical barrier and does not have any antimicrobial properties.
The inventor has previously described (in co-pending U.S application Ser. No. 09/345282 filed on Jun. 30, 1999) medical catheters and implants whose surfaces are covered by photosensitizers or contain photosensitizers. An embodiment of the invention has a photosensitizing compound affixed to or near the device surface with means to periodically activate the compound by suitable illumination. Bacterial growth and adherence to medical devices is overcome for extended periods of time by using the invention. It is impractical to cover consumer items in a similar manner as bleaching will occur over time due to exposure of the surfaces to ambient light. The use of laser as the activation radiation may also be impractical.
It would be useful to have a method to impart antimicrobial properties to product surfaces after they are manufactured, where the microbial action is renewable, and where the microbial agent does not permit the development of resistance by the microbes.

Method and substance for obtaining surfaces with antimicrobial properties


A seat assembly for sliding along opposing rims of a bathtub is disclosed. The seat assembly includes a seat member, a friction element affixed to the seat member so as to extend under the seat member, and a flexible slider affixed to the seat member so as to also extend under the seat member. The slider and friction element are positioned and configured so that in a first state, if the seat member is positioned on the opposing rims without additional weight on the seat member, the slider holds the friction element up off a rim while facilitating sliding of the seat member along a rim. In a second state, if the seat member is positioned on the opposing rims with a human weighing over 50 pounds sitting on the seat member, the friction element can contact the rim and thereby impede sliding of the seat member along a rim.

This invention relates to bathtubs and, in particular, to movable seats for use therewith.
Humans usually use bathtubs while standing or lying down in the tub. In the case of standing use, an overhead shower typically supplies the water for washing the user, and the bathtub collects and drains the water. In the case of use when the user is lying down, the user typically partially fills the bathtub with water, and then lies down on the floor of the bathtub to soak in a partially immersed fashion.
However, for those who have difficulty getting up by themselves from a reclining position or standing for prolonged periods (e.g. some disabled or elderly), some tubs have been structured with an integrally molded seat so that those users can sit up a bit higher (rather than all the way down on the tub floor). As a result, getting back up to leave the tub is less difficult.
However, this permanently converts the tub into one which uses up much space for the special seating arrangement. Others living at the same location who might prefer a more conventional bathing experience are precluded from that opportunity in this situation, or must use another bathroom.
Removable seats have therefore been proposed for use with conventional bathtubs. See e.g., U.S. Pat. Nos. 390,407; 5,090,068; 5,475,880; and 6,035,459. However, it is desirable that such seats be relatively lightweight so as to be positionable by even the infirm, yet be able to be fixed in a desired position. Also, it is desirable for such seats to be movable between selected fixed positions depending on what type of bathing is desired, and by whom. Further, it is desirable that such seats not themselves take up additional bathing room inside the basin.
There are a variety of other design constraints as well. For example, U.S. Pat. No. 390,407 requires the user to manually adjust a clamping mechanism. While this helps fix the seat at a particular position, the clamping mechanism is awkward to use.
Also, U.S. Pat. No. 5,090,068 permits the user to slide the seat, but requires a lifting motion to achieve that. The lifting aspect can make this seat assembly more difficult for some infirm to use.
Further, U.S. Pat. No. 5,475,880 requires the user to install a track system. This adds weight, cost and complexity to the assembly.
Moreover, U.S. Pat. No. 6,035,459 requires the user to manually operate a brake to fix the seat. Further, it leaves a vertically extending post which can cause tripping problems in the bathroom.
Hence, a need exists for a removable bathtub seat that is lightweight and inexpensive, easily positioned on bathtub rims, and fixable at selected locations in a highly intuitive and automatic fashion.


A mixer includes a transconductance circuit and a mixing circuit. The transconductance circuit includes a capacitor and first and second transconductance modules. The first transconductance module converts a single-ended to-be-shifted voltage signal at a first terminal of the capacitor into a first input current signal. The second transconductance module converts a voltage signal at a second terminal of the capacitor into a second input current signal that cooperates with the first input current signal to constitute a differential input current signal pair. The mixing circuit mixes the differential input current signal pair with a differential oscillatory voltage signal pair to generate a differential mixed voltage signal pair.

Referring to FIG. 1, a conventional down-conversion mixer includes a first single-ended to differential converting circuit 51, a second single-ended to differential converting circuit 52, a transconductance circuit 53, a mixing circuit 54 and an output unit 55. The first single-ended to differential converting circuit 51 converts a single-ended oscillatory voltage signal into a differential oscillatory voltage signal pair. The second single-ended to differential converting circuit 52 converts a single-ended input voltage signal of radio frequency into a differential input voltage signal pair. The transconductance circuit 53 converts the differential input voltage signal pair into a differential input current signal pair. The mixing circuit 54 mixes the differential input current signal pair with the differential oscillatory voltage signal pair to generate a differential mixed voltage signal pair of intermediate frequency. The output unit 55 amplifies and buffers the differential mixed voltage signal pair to generate a differential output voltage signal pair.
A noise figure (NF) of the conventional down-conversion mixer can be expressed by the following equation:
                                                        NF              =                                                          1                +                                  (                                                            NF                      52                                        -                    1                                    )                                +                                                                            NF                      53                                        -                    1                                                        G                    52                                                  +                                                                            NF                      54                                        -                    1                                                                              G                      52                                        ·                                          G                      53                                                                      +                                                                            NF                      55                                        -                    1                                                                              G                      52                                        ·                                          G                      53                                        ·                                          G                      54                                                                                =                                                                                NF                    52                                    +                                                                                NF                        53                                            -                      1                                                              G                      52                                                        +                                                                                NF                        54                                            -                      1                                                                                G                        52                                            ·                                              G                        53                                                                              +                                                                                NF                        55                                            -                      1                                                                                G                        52                                            ·                                              G                        53                                            ·                                              G                        54                                                                                ,                                                          Equation                                                  1            where NF52, NF53, NF54 and NF55 respectively denote noise figures of the second single-ended to differential converting circuit 52, the transconductance circuit 53, the mixing circuit 54 and the output unit 55, G52, G53 and G54 respectively denote power gains of the second single-ended to differential converting circuit 52, the transconductance circuit 53 and the mixing circuit 54, and G32<1.
The conventional down-conversion mixer occupies a relatively large area. Moreover, FIGS. 2, 3 and 4 respectively illustrate a conversion gain, the noise figure and isolation between input terminals of the conventional down-conversion mixer at which the single-ended oscillatory voltage signal and the single-ended input voltage signal are received, under a circumstance where the single-ended input voltage signal has a frequency within a range of 70 GHz to 100 GHz or within a range of 80 GHz to 100 GHz, and where the single-ended oscillatory voltage signal has a frequency lower than that of the single-ended input voltage signal by 0.1 GHz. It is known from FIGS. 2, 3 and 4 that, for the conventional down-conversion mixer, the conversion gain is relatively low, the noise figure is relatively high, and the isolation is relatively low.


The present invention provides a process control stabilizing system including a cleaning device for the corona wires which allows the process control to be carried out optimally based on exact information which is obtained by certain sensors while a discharge from the main charger unit is kept uniform. The system is constructed so that an electrode cleaner is activated before the detection of the surface potential and/or the detection of the optical density, and in addition, the cleaning operation will be operated until the detection result falls within a predetermined range. Alternatively, the system causes detection of the surface potential and/or detection of the optical both before and after a cleaning operation by the electrode cleaner. The cleaning operation will be repeated until the difference between the first and second detections falls within a predetermined range. In the above operations, if the repetitions of the operations in excess of the predetermined number of times cannot make the detection result fall within the predetermined range, the system preferably activates a warning device and/or prohibits a copying operation.

(1) Field of the Invention
The present invention relates to a process control stabilizing system which is incorporated in an image forming apparatus and controls the electrophotographic process so as to provide an image in an optimum condition.
(2) Description of the Related Art
Generally, with regard to photoconductive members for use in image forming apparatuses, the surface potential of a photoconductive member varies largely dependent upon environmental conditions of the location where it is used. As regards OPC's (organic photoconductors), for example, the surface potential at low temperature environment is lower by 100 to 150 V than that at a normal temperature due to dependance of the mobility of photocarriers therein. With regard to Se-photoconductors, the amount of thermally excited carriers varies dependent upon temperatures, so that the potential increases by 50 v at a low temperature and decreases by 50 to 100 volts at an elevated temperature. The temperature dependence is problematic. Further, the OPC's exhibit a tendency that the thickness of the photosensitive layer thereof is reduced by mechanical stresses (that is, scratching or abrasive effects by a cleaner blade and/or copy paper) with the total copy volume increased. The variations of the surface potential in a photoconductive member due to the aforesaid effects, would lower the density of an image copied or bring about other great deterioration to image quality. Further the variations would influence the toner consumption amount for development to give rise to a waste of toner. On the other hand, as to developers, the amount of frictionally generated static electric charges of toner varies depending on environment charges. Specifically, under a circumstance at a low temperature with low humidity, toner tends to acquire more charges resulting in lowering in image density (i.e. the halftone density lies within approximately 0.8.+-.0.4), while toner powders get less charges at an elevated temperature with a high humidity, to induce increase of the image density, deterioration of gradation reproduction behavior, and/or a waste of toner etc.
Moreover, even if the copying mode were changed, the effect would sometimes fail to reflect due to the disadvantages stated above. That is, the image quality between different modes would not be clear or distinguishable, or the intention to lessen the toner consumption could not be achieved. In order to eliminate these defects and drawbacks, there are disclosed various proposals of process controls one of which is cited as Japanese Patent Publication Sho 61 No. 29502. A method of the publication includes the steps of measuring electric charges in both dark and light portions and then controlling the condition for charging based on the measurement in the dark portion while controlling the condition for exposure or development with reference to the measurement in the light portion, in order to provide exactly controlled images.
Another method includes the steps of detecting a surface potential of a photoconductive member at proper times by surface potential meter provided inside copier and adjusting optimally based on the detected quantity the power of charger and/or the applied voltage for exposure lamp. Still another method includes the steps of exposing an image of a referential white board etc. onto a photoconductive member, developing the latent image into a visual image with toner, measuring the density of the toner-image by an optical sensor, and optimally adjusting based on the detected quantity the power of charger, the toner density of developer, the bias voltage for development, and the power voltage for exposure lamp.
With the conventional arrangement described above, however, it has been impossible to get proper information on images from sensors due to a lack of uniformity in discharging by a charger. The charger is at all times exposed to and polluted with toner powders splashing inside the copier, an evaporated and splashed silicon oil used in heat-fixing process, and/or any other dirt outside the copier. This makes it very difficult to keep discharge of the charger uniform across the longitudinal direction of a photoconductive member. For this reason, unevenness in discharging occurs and this causes the photoconductive member to have an uneven distribution of its surface potential in the longitudinal direction thereof, or the toner-developed image on the photoconductive member for the referential white board to become uneven. If a surface potential meter or optical sensor samples the portion with such unevenness, the resultant measurement cannot represent a cross-section or typical value of the entire system, and the process of the system might disadvantageously be controlled based upon the erroneous measurement. This failure to control the process may possibly bring about various serious problems. That is, a process condition widely deviates from an optimally controlled condition might cause fluctuation of the quality of images. A defectively controlled process condition might damage the photoconductive member. Alternatively, an unusual increase in toner density fails to provide balanced frictional electrification charges to toner powders, yielding weakly charged toner which would make images foggy. Moreover, augment of toner might cause the toner powders to splash, polluting the inside of the copier.
To overcome these problems, that is, to measure against the uneven distribution of static electric charges on the photoconductive member, various proposals have been made. For example, Japanese Patent Application Laid-Open Hei 2 No. 179659 discloses a corona charging device in an electro-copier able to detect the unevenness of charges and automatically executing cleaning operation of a corona charger when the charger causes uneven discharge. The device detects irregularity of toner density of the image on a photoconductor as an indicator for unevenness of discharging by the corona charger. More specifically, if a toner density sensor incorporated in the device exhibits an output power lower than a threshold level, the device recognizes occurrence of the unevenness in discharging. Based upon the detection, cleaning means is activated which comprises cleaning pads sandwiching the charging wires stretched in the charger and being slidable so as to be driven by a stepping motor. Thus, on the occasion of detecting uneven toner density, the stepping motor is activated to execute cleaning operation.
Like the above disclosure, Japanese Utility Model Application Laid-Open Hei 3 No. 20349, relating to an image forming apparatus equipped with an automatic cleaning mechanism in a corona charger, measures the density of a referential image on its photoconductive member by using detecting means comprising plural photosensors, and executes cleaning operation in the same manner as described of the above prior art by moving and sliding the cleaning mechanism when difference between the density values detected by the different photosensors is found to exceed a predetermined level.
Another Japanese Utility Model Application Laid-Open Hei 2 No. 123947 proposes a technology relates to an image recording apparatus comprising a plurality of developing units, wherein charging wires in the charger are cleaned by a cleaning means every time a different developing unit is selected. Here the cleaning means used is of slidable type with the same structure described above. The object of this apparatus is to conduct cleaning operation of the charging wires in accordance with the selection of the developers.
Of these three publications, the first and second articles disclose the apparatuses all of which execute cleaning operation of the charging wires in the charger based on the comparison of the output power of the toner density sensor or sensors with a predetermined value. In consequence, it is true that the charging wires are cleaned effectively, but it is not that the process is controlled exactly based upon the density change, so that these cannot be thought of as the most suitable process control methods.
The third article discloses a technology in which the charging wires in the charger are cleaned before a currently engaged developing unit is replaced by a different unit in order to change the developing process. Therefore, this method is not the one that keeps on controlling a certain developing unit with reference to its output information.
On the other hand, Japanese Patent Application Laid-Open Hei 3 No. 105360 discloses an image forming apparatus capable of performing automatic maintenance including cleaning operation of charger in parallel with the operations for attaching and detaching an IC card as a portable external memory means. Cleaning means disposed slidably with sandwiching corresponding electrodes is provided for each of a primary charger, a transfer charger and a separation charger, and is adapted to be driven by a respective motor supplied by a motor driving power source. The activation of these motors, in consequence the cleaning operation, is determined by a counter for total copy number. Here, the connector of the aforesaid IC card serves as a detecting means, being connected detachably to the apparatus body.
The method is to control automatically certain subjects for maintaining the image forming apparatus using the IC card. Nevertheless, in this method, the wires of the chargers will not be cleaned until the detecting means sends out the order i.e, the signal for cleaning. In other words, the method is not the one that carries out an exact process control following the information from the photoconductive member.

Process control stabilizing system including a cleaning device for the corona wires


A method for detecting presence of nucleic acid amplification in a test droplet. A set of detection electrodes are provided in contact with a fluidic channel. The test droplet is provided in vicinity of the detection electrodes through the fluidic channel. An alternate current (AC) power at a first frequency is applied across the set of detection electrodes. A first measurement value that reflects electrical impedance of the test droplet at the first frequency is obtained. This value is compared with a corresponding reference value, wherein the corresponding reference value is obtained by measuring a reference droplet containing known amplified nucleic acid or known unamplified nucleic acid at the first frequency. The presence of amplified nucleic acid in the test droplet is thus determined based on the comparison.

Polymerase Chain Reaction (PCR) has been widely used to amplify a specific region of a DNA or RNA strand across several orders of magnitude, generating thousands to millions of copies of a particular DNA or RNA sequence. It has long been adopted as a standard procedure in the detection of nucleic acid targets due to the techniques' sensitivity and accuracy. Droplet microfluidics' ability to rapidly generate isolated reaction chambers serves as a convenient platform for the adaption of PCR. Because of the synergy, droplet PCR or digital PCR has garnered much research interest in recent years. Real-time PCR is a tool for DNA or RNA quantification that measures the accumulation of DNA or RNA product after each round of PCR amplification.
Conventionally, as a polymerase enzyme completes the complementary strand, a fluorescent label is release from a fluorescent probe, creating a fluorescent signal that is detectable optically. However, the need for fluorescent illumination as well as detection and the processing required to prepare fluorescent markers generally increases the cost of such systems.
There is a need to reduce the cost of detecting nucleic acid target. It would be advantageous to provide a method of PCR detection without the need for fluorescently labeled substrate. It would also be advantageous to provide a detection process feasible for real time detection of DNA or RNA amplification and high throughput integrated microfluidic platform.

Real-time, label-free detection of nucleic acid amplification in droplets using impedance spectroscopy and solid-phase substrate

The Regents of the University of California Corporation


A hand-held controller wand including three angular rate measurement sensors is coupled to a computational device for translating roll, pitch, and yaw data into translation and rotation signals or commands that effect the movement of an external device's control point, which may be an end effector of a robot. A transformation matrix is continually updated from the angular rate information obtained from the hand-held controller. This matrix is used to update a direction vector. A value may be stored in the computation device corresponding to a predetermined speed of movement. A button or other convenient control allows the operator to control translational movement of the end effector or other controlled device in a direction defined by the orientation of the hand held controller at the predetermined speed, thus providing an intuitive control input for real-time direction and programming of movement. Because the present orientation of the wand is also known to the computational device, rotational movement may also be directed. Translation and orientation motion input may be provided simultaneously or separately, in accordance with the programming and/or under control of the computational device. The computational device translates the computed direction vector into signals corresponding to commands that depend upon the device being controlled; such translation is especially suited for robot controllers, because such controllers accept simple movement commands that may readily be computed from the direction vectors. However, the controller is also useful for other applications in which motion information is required, including the motion of real objects and virtual reality.

1. Field of the Invention
This invention relates to a method and apparatus for controlling a movable object, and more particularly to a method of positioning, orienting, and programming movements of a tool held by a robot arm, and an apparatus therefor.
2. Discussion of the Prior Art
Many activities involve control of the movement of an object in a three-dimensional space. So-called "real time" manipulation of graphic objects in computer simulations, e.g. video games, flight simulators, virtual reality, etc., is an example. Another is the control and programming of industrial robots, particularly the robot arms used in assembly operations to manipulate tools such as spray painters or welders. Such control is achieved using various control systems, typically digital controllers implemented in computers, which move the tool along either a precalculated trajectory or a reference trajectory provided by spatial input devices such as keypads, joysticks or trackballs, in a teach-repeat mode or in real time.
While programmable robots in these applications perform repetitive and often dangerous tasks more efficiently than human, they must be programmed by humans. A programmer typically must direct the robot in a stepwise manner through each detail of each task to be performed with only the aid of a keyboard or a handheld keypad called a "teach pendant." Because of the design of these teach pendants, this progrmming has been done by moving or rotating the robot arm along one axis at a time in a domain with typically four to six degrees of freedom. with constant, careful observation of where the tool, or end effector is located. Complex motions are very time consuming to program because of the nature of the programming tools in use today. Robots are typically programmed by moving the robot arm in separate or "decoupled" orthogonal straight-line or rotational movements parallel to or around the axes of the reference coordinate frame or around axes of various robot joints. Thus, each movement must be taught as a combination of individual points on a spline. However, the orientation of the reference coordinate frame is not always immediately evident or intuitive to the programmer, thus making it necessary to jog the robot arm to see if a particular command to be programmed causes motion in the intended direction. Aside from being inefficient and time-consuming, programming in this way can be destructive or even dangerous, since an improper movement of the robot during programming could damage or destroy a tool or a workpiece, possibly endangering personnel in the vicinity.
Also, present-day robotic controllers use inconsistent user interfaces, both between different manufacturers and even between different model robots of the same manufacturers. Thus, when a robot needs to be reprogrammed, adjusted, or replaced, a person trained in the idiosyncrasies of a particular user interface must typically be brought in or on staff to do the required work. Although others could be trained to use a new user interface, the cost of running an assembly line can be so high (on the order of $15,000 to $25,000 per minute in some automotive assembly lines) that an inefficient or error-prone programmer cannot be tolerated.
While inconsistent or non-standard user interfaces are the norm in the robotics industry, most robots are provided with programming languages that can readily accept data corresponding to the robot's workvolume and desired coordinate frames (i.e., world, tool). Also, the typical robot controller can readily translate arbitrary move-to and rotate-to commands into joint angle data, and into the control signals needed to move the robot arm into the desired position.
Joysticks and trackballs have been used as spatial input devices for programming robots, but they are incapable of providing sufficiently intuitive controls corresponding to each of all the possible movements of a robot arm. For example, while it is simple enough to provide three degrees of freedom in trackball with sensors and map rotations of the trackball into forward, reverse, and right-left motion corresponding to orthogonal movements of the robot arm in a plane, to use the trackball for directing the robot in a third translational direction, it is necessary to provide sensors for detecting rotation of the trackball about a third orthogonal axis. Unfortunately, while the other two orthogonal motions of the trackball can be intuitively related to the motion of the robot arm (i.e., left-fight and up-down motions of the wrist vs. the same linear motion of the robot arm), the third motion requires a twisting motion of the wrist which does not intuitively correspond to the third orthogonal motion of the robot arm. While a separate control can be added for this third translational motion, its use would be difficult and nonintuitive.
Ideally, a spatial input device replacing a teach pendant should also have the capability of providing simple commands that restrict motion of the robot as desired. Consider, for example, a robot arm spray painting the side of a van on an assembly line. If it is known that the (possibly irregularly-shaped) workpiece is to be positioned at a fixed position, it may be desirable to ensure that, whatever manipulation is done to the robot arm, the endeffector remains a fixed distance (or at a fixed orientation) relative to the nearest part of the workpiece. In the spray painting example, motion commands to the robot controller could be constrained to ensure that the spray painting nozzle at the end of the robot arm is maintained at a fixed distance and angle with respect to the side of the van and travels at a uniform speed, ensuring a uniform paint coating. During programming of the robot, such constraints could protect the tool, the robot arm, and the workpiece from damage. Perhaps more importantly, movements of the robot arm could be confined within a limited volume of space to protect workers who must be on the factory floor while robots are operating--including, of course, those who program the robots.
Aside from teach pendants and track balls, other programming devices are known. Linkages are devices that resemble the device they control; for example, a four degree of freedom linkage would control a four degree of freedom robot. However, these linkages are usually table mounted, and intuitive control is lost if the device is taken off the table. Also, linkages also have a limited range of motion. Gloves and other anthropomorphic devices used as controllers and programming input devices physically and undesirably tie the operator to the computer. This type of device also does not provide intuitive control for translational movement, and are difficult to implement if the person using the glove or other device is not stationary in his position within the work volume. Devices relying on emitter/receiver technology, such as IR and acoustic transmitters and receivers usually have limited range and are primarily limited to line of sight control. These devices do not work well in noisy industrial environments.
There is thus a need for an easy-to-use, intuitive real-time 6 DOF (degrees of freedom) input device to replace difficult-to-use teach pendants and unintuitive joysticks and trackballs. This input device should provide intuitive control no matter where a use is positioned or oriented in the workplace, and should not require table mounting or have to be within a line of sight from a sensor and with no limitation as to the type of environment. It would further be desirable to provide both simple and complex motion control (i.e., essentially simultaneous motion in several reference directions at the same time) with the same device using easily understood commands. Moreover, it would be highly advantageous to provide both an unlimited range of motion commands when desired as well as a means for constraining motion commands from the spatial input device to provide, for example, confinement of robot motion to a fixed volume of space, "smoothing" of a tool trajectory, or a maintenance of constant distance between a tool and a workpiece. It would also be advantageous to provide both coarse and fine motion control.
In addition to uses in robotics, an input device having the desired characteristics could be used to input 6 DOF motion for any hardware or virtual object or device, such as cranes, flight simulators, or computer simulated devices or objects, either to program these devices or to provide real-time, simultaneous 6 DOF control.

Method and apparatus for controlling and programming a robot or other moveable object


A phenylmethylpolysilane polymer is prepared by the addition of a small amount of phenylmethyldichlorosilane to dimethyldichlorosilane and reduction of the resulting mixture. The polymer is a gum or meltable resinous material which has utility as a precursor for preparing silicon carbide fibers.

As disclosed in "Polydimethylsilane", JACS, 71, 963-4 (1964), C. A. Burkhard synthesized permethylpolysilane polymer (Me.sub.2 Si).sub.n. The synthesis proceeded from dimethyldichlorosilane and sodium metal as shown by the following formula: EQU Me.sub.2 SiCl.sub.2 +2Na.fwdarw.(Me.sub.2 Si).sub.n +2NaCl.
The polymer formed in this manner is an infusible solid for which there is no known technical use.
More recently, in Japan, Yajima et al have shown that a permethylpolysilane polymer of the right molecular weight range can be drawn into fibers. Also the fibers upon heating are transformed into fibers of .beta.-silicon carbide as shown by the following equation: ##EQU1## The resulting fibers are extremely strong. The tensile strengths claimed exceed those of any known material, including carbon and boron fibers now used to reinforce high temperature materials, such as turbine blades, wing edges of high performance aircraft, and the like.
Yajima et al obtain their permethylpolysilane polymer by thermolysis of dodecamethylcyclohexasilane, (Me.sub.2 Si).sub.6. When (Me.sub.2 Si).sub.6 is heated to 400.degree. C., it undergoes ring-opening polymerization to give polymers of various molecular weights. This product is solution fractionated since only polymers in the right molecular weight range can be spun or drawn into fibers.
It is a principal object of this invention, therefore, to provide a polymer that can be used directly to form fibers.
Another object of the invention is to provide a phenylmethylpolysilane polymer which undergoes thermolysis to silicon carbide.
Another object of the invention is to provide a process for preparing the phenylmethylpolysilane polymers.
Other objects and advantages of the invention will be apparent to those skilled in the art upon consideration of the accompanying disclosure.

Phenylmethylpolysilane polymers and process for their preparation

The United States of America as represented by the Secretary of the Air Force


A high speed, high sensitivity inspection system (10) is provided, which is substantially impervious to external factors such as vibration. The inspection system is an optical system which employs phase contrast interferometry to achieve the desired results. The systems makes use of a "black beam" at the optical axis of the system, and uses at least two detectors to determine the intensity of the light beam after passing through a work piece.

Recently, manufacturers of virtually every type of electrical and electronic component have made significant strides in reducing component size. As sizes were reduced, it became increasingly important to assure that the fabrication of the components was free from defect. Defects on these increasingly small components could range down to a size of a few microns, or less. Cracks and scratches in glass substrates can have widths of less then 0.0003 mm, yet still propagate during the manufacturing process. Defects of even this size will therefore render many of today's electronic components inoperable.
Examples of electronic components requiring defect free surfaces include flat panel displays (FPD's) such as active matrix liquid crystal displays (AMLCD's), optical disks, optical flats, etalons and precision windows, prisms, and laser mirror substrates, to name but a few. Specific materials, such as transparent coated optics for use in LCD's and solar cells, also require surfaces that are free from defect. Added to the fact that defects in these materials can be as small as micron, is the fact that these devices or surfaces can have areas of one meter or more.
With respect to FPD's and particularly to AMLCD's, inspection is critical in that manufacturers report manufacturing yields of such devices at less then forty percent. One area which would provide substantial improvement to manufacturing yields would be to improve the quality of inspection of glass substrates prior to beginning the manufacturing process, after the deposition of preliminary layers of material, and during the overall process to screen for dust. Initial inspection of the substrates would screen for breaks, chips, cracks, warpage, and for veins and bubbles. Other key inspection criteria are for dust, scratches, and organic dirt.
It has long been known that the best way to inspect large area, high quality surfaces is to use light directed at the surface, and measure the amount of scattering, if any, caused by specific defects in the surface under investigation. A major problem has resulted from instances in which light beams reflected off of minute defects are scattered so slightly as to be indistinguishable from "noise" in the monitoring system. These types of situations typically arise when the defect is smaller than the diffraction limit of the light based system. Similarly, these problems will occur when the depth of the defect is less than the wavelength of the illuminating beam. These limitations in light scattering systems have rendered them unfit for inspecting extremely high resolution devices, since minute defects (although large enough to render the device inoperable) are undetectable by the system.
In an effort to overcome these shortcomings in light scattering systems, interferometric systems have been devised. Interferometry refers to measuring differences in the time or phase of two or more signals received by sensors spaced a known distance apart. These types of interferometric systems are widely known, and in laboratory usage today. However, a major limitation of interferometric systems is that detection of the phase must be done in the specular direction since the wave fronts emerging from the source and the defect are overlapping in space (i.e., are propagating together ). This results in a high DC level which must be overcome at the detection of the signal. Phase contrast interferometric methods overcome the problems associated with high DC level, but are extremely sensitive to adjustments, vibrations, misalignments, etc. Further, interferometric systems have fields with cyclical variations, and consequently a large oscillating phase term. Hence, the surface calculation becomes ambiguous since any point of the field can be interchanged with another, one wavelength distant. An additional limitation is the necessity for a reference beam, making the entire system sensitive to the reference adjustment within the space of a single wavelength.
These types of interferometric systems have proven successful, particularly in laboratory applications, since they possess heretofore acceptable sensitivity to defects, and are capable of discerning defects from background noise. Nonetheless, these types of systems have not proven useful in industrial settings. This is because their high sensitivity is easily effected by external influences, such as vibration and system adjustments.
Attempts have been made to eliminate these types of problems. The usual method of removing high DC levels present in interferometric systems is to apply phase contrast interferometry. This method provides adjustments to the two interfering beams of light so that the nominal optical path difference inside the system is one half of a wavelength. Consequently, after interference, the resulting amplitude is zero. Thus, a small change in one of the two interfering beams will result in a significant change in the resulting amplitude, and hence a significant measurement signal, free from a DC component.
The advantage of the phase interferometric system resides in the fact the phase contrast has a "zero" response to a "zero" signal, while a regular interferometric system has a "non-zero" reference level. The disadvantage of the phase contrast method is its extreme sensitivity and inflexibility to adjustments in the system. Any change in the nominal path length in the system will cause both a non-zero DC level, and a change in the signal contrast at the detector. This problem is exaggerated when high speed scanning is taking into account, as in industrial applications.
Further, and of major importance to manufacturers of FPD's and particularly to AMLCD manufacturers, is the fact that resolution levels for these type of systems remains below acceptable levels. For example, spatial resolution and depth resolution for conventional interferometers is approximately 2.0 .mu.m and 0.01 .mu.m respectively, while being extremely slow and unstable.
Accordingly, there exists a need for a light based inspection system with very high sensitivity to minute changes in the optical path (and hence the presence of defects on the investigated surface). The inspection system should be able to detect defects below the diffraction limit of the optical system, and be able to do so in a relatively fast manner. The inspection system should also have little or no influence from external factors.

Differential phase contrast inspection system with multiple detectors