An improved heater wire and electro-thermal controller suitable for use in electric heating appliances such as electric blankets and heating pads. The heater wire is formed with a first conductor for heat generation and a second conductor for sensing. The first conductor and second conductor are wound as coaxial spirals with an insulation material electrically isolating the two conductors. The two spirals are counter-wound with respect to one another to insure that the turns cross, albeit on separate planes, several times per inch. With the conductors thus formed, if the insulation separating the conductors fails, the first and second conductors will come into electrical contact to facilitate detection of this hazardous condition. The controller of the present invention includes an electronic control unit a sensor input circuit, a heater driver circuit and a user interface circuit. The heater driver circuit is operatively coupled to the first conductor and provides a heater voltage in response to a signal received from the electronic control unit. The sensor input circuit is operatively coupled to the second conductor, measures a resistance and voltage associated therewith, and provides a signal to the electronic control unit in response thereto. The electronic control unit is responsive to signals received from both the user interface circuit and sensor wire input circuit and controls the heater driver circuit accordingly.

1. Field of the Invention
The present invention relates generally to heater wire and more particularly relates to heater wire having an integral sensor wire and an improved controller therefor.
2. Description of the Prior Art
Specialized wire for performing electro-thermal conversion, commonly referred to as heater wire, is well known in the prior art. Heater wire is used in a variety of applications including measurement systems, industrial heating processes, and in textile articles, such as electric blankets.
When used in personal textile articles, such as electric blankets, it is critical that the heater wire is used in conjunction with over-heat protection to reduce the risk of fire. Several attempts have been made in the art of electric blanket design to incorporate such protection. These designs attempt to balance user comfort and user safety. To achieve maximum comfort to the user, the heater wire should be permitted to operate as close to the maximum temperature of the article as permitted. To achieve maximum safety, the heater wire must not exceed the maximum temperature or an enhanced risk of fire results.
FIG. 1 illustrates a simplified schematic diagram of a heater wire 2 formed with a plurality of thermostats 4 interposed therein. The heater wire 2 is formed from a resistive material and generates thermal energy when a current is passed through it. The thermostats 4 are temperature sensitive switches, such as bimetallic switches, which are normally closed and open only in response to the detection of a predetermined temperature limit. This configuration, which is well known in the art, provides discrete points of over temperature sensing and protection. However, the protection offered by this configuration is limited in that only a certain number of points of protection are distributed throughout the length of the heater wire 2. Further, each thermostat 4 requires two electrical interconnections to the heater wire 2. These connections tend to increase manufacturing costs and decrease product reliability. In addition, the thermostats have a relatively high thermal mass which results in a slow response to rapid temperature changes. As a result, the temperature of the heater wire tends to overshoot the desired temperature.
To overcome the problems associated with the heater wire embodiment illustrated in FIG. 1, heater wires have also been formed which are thermally self limiting. An example of such a self limiting heater wire is disclosed in U.S. Pat. No. 4,309,597 to Crowley. Such a device is illustrated in the simplified schematic diagram in FIG. 2. The heating wire of FIG. 2 includes a pair of conductors 6, 8 and a positive temperature coefficient (PTC) resistive material 10 disposed therebetween. The PTC material 10 forms a distributed resistance between the conductors 6, 8.
When a constant voltage is applied across the two conductors 6, 8 a current flows through the PTC material 10 and heat is generated. As the PTC material 10 is heated, the resistance of the PTC material 10 increases and the current is reduced accordingly. In this way, the heater wire effectively self regulates to provide over temperature protection. This embodiment of a heater wire eliminates the manufacturing problems associated with the connection of multiple thermostats within a resistive heating wire. However, the PTC material 10 is typically a high carbon content material and is extremely flammable in the presence of electrical arcing. Therefore, should cracks arise in the PTC material 10 across which electrical arcing occurs, a high risk of fire is presented.
U.S. Pat. No. 4,503,322 to Kishimoto et al. discloses a further embodiment of a self regulating heater wire. The heater wire formed in accordance with the '322 patent is shown schematically in FIG. 3. This heater wire includes three conductors 6, 8, 12 and two thermal-resistive layers 10, 14. Two of the conductors 6, 8 and one thermal-resistive layer 10 function as a heater wire essentially as described in connection with FIG. 2.
The second thermal-resistive layer 14 is interposed between one of the heater wire conductors 6, 8 and the third conductor 12, which is used as a sensor wire. As heat is generated in the first layer 10, the resistance of the second thermal-resistive layer 14 changes in response. This change in resistance between the conductors 8, 12 is indicative of the temperature of the heater wire and can be used to regulate the heat generated by the heater wire. While this configuration of a heater wire provides a sensor wire which enhances the controllability of the heater wire, the fundamental problem of the high flammability due to the high carbon content of the thermal-resistive layers is still present.

Heater wire with integral sensor wire and improved controller for same


The invention includes a yoke assembly containing a top and a bottom proximity latch magnet. The invention includes a voice coil attached to a voice coil bias steel. The crash stop includes a magnetic proximity latch created by the voice coil bias steel attracted to the top and bottom proximity latch magnets. It may also include using the magnetic proximity latch with a magnetically weakened contact latch. Experiments have shown that the combined magnetic proximity latch and the magnetically weakened contact latch require significantly less initial releasing force than the prior art crash stops, and meet rotary shock requirements. The invention includes making the actuator assembly, the voice coil motor assembly, and the CSS hard disk drive. The invention includes operating the CSS hard disk drive with at least the magnetic proximity latch.

1. Field of the Invention
The present invention relates to crash stops which park the read-write heads near the disk pack spindle in a Crash Start/Stop (CSS) hard disk drive.
2. Background Information
Modem hard disk drives include a servo controller driving a voice coil which acts upon an actuator assembly to position a read-write head near a track on a rotating disk surface. The read-write head communicates with the servo controller, providing feedback, which is used in controlling the read-write head's positioning near the track. The read-write head is embedded in a slider, which floats on a thin air bearing a very short distance above the rotating disk surface.
A voice coil motor assembly typically includes a voice coil, which swings at least one actuator arm in response to the servo controller. Each actuator arm includes at least one head gimbal assembly typically containing at least one slider. The head gimbal assembly couples to the actuator arm in the voice coil motor assembly.
A hard disk drive may have one or more disks. Each of the disks may have up to two disk surfaces in use. Each disk surface in use has at least one associated slider, with the necessary actuator arm. Hard disk drives typically have only one voice coil actuator. The disk(s) rotates about the spindle motor hub, which contains all of the disks.
When the hard disk drive is not in operation, industry practice is to park the actuator arms holding the read-write heads either near the spindle motor hub or away from the spindle motor hub. This practice evolved as a way to minimize contact and collision damage between the read-write head(s) and the disk surface(s). This invention relates to hard disk drives, which park the read-write heads near the spindle motor hub. These hard disk drives are often known as "Crash Start/Stop" or CSS hard disk drives.
Some hard disk drives use the other crash stop mechanism, parking the read-write heads away from the spindle motor hub, essentially outside the disk diameter. These are sometimes referred to as OD or "Outside Diameter" hard disk drives.
Both crash stop mechanisms must prevent damage to the actuator assembly, particularly the read-write heads, by withstanding rotary shocks in the plane of the disks. Today hard disk drives must withstand rotary shocks of radial shock strength lasting one or more milliseconds. The radial shock strength is often 30,000 radians per second per second.
There is a problem with existing magnetic latching mechanisms used in CSS hard disk drives. The latching mechanism commonly used is a magnetic contact latch, which requires a strong initial releasing force to unpark the actuator assembly. This strong initial releasing force may be 100 to 120 grams of force. Magnetic contact latches require this strong initial releasing force only for a brief distance to unpark the actuator assembly. This requirement creates control difficulties immediately after the initial release of the actuator assembly. The actuator assembly swings hard and fast at first. Time and energy are lost bringing the actuator assembly motion under control. What is needed is a latching mechanism for a CSS hard disk drive meeting the rotary shock requirement, while requiring much less initial releasing force.

Disk drive voice coil motor yoke assembly having proximity latch magnet pair attracting and holding voice coil bias steel therebetween


Improved ligament anchor structures and methods for affixing graft ligaments to bone are provided. The ligament anchor assembly includes a sleeve having gripping means for being firmly secured within a bone tunnel and a bore extending therethrough. The graft ligament is secured to an insert sized to pass through the bore in the sleeve. The bore in the sleeve and the external surface of the insert have cooperating asymmetrical teeth formed thereon so that the insert can pass through the sleeve in only one direction. The sleeve is first placed in a bone tunnel and the opposite end of the ligament secured in the corresponding bone, followed by final adjustment of the ligament tension without disturbing the anchors of either end of the graft ligament.

Due to the frequency of injury to the anterior cruciate ligament (ACL), especially in sports, and similar injury to other ligaments and related structures, there is a great deal of prior art dealing with replacement of these structures with graft ligaments. Much of this prior art is concerned principally with ensuring proper alignment of bone tunnels drilled in the tibia and femur to receive the opposed ends of the graft ligament, preparation of the surgical site, i.e., by removing sufficient bone to allow the graft to function properly, and with preparation of suitable graft ligaments, commonly by harvesting donor bone/tendon/bone structures from the knee of the patient. See generally, "The Paramax ACL Guide System Surgical Technique", a brochure published by Linvatec Corporation of Largo, Florida in 1992, and incorporated by reference herein. Other sources of replacement ligaments, including allograft and autograft ligament substitutes, are within the skill of the art and are intended to be included within "graft ligament" as used herein.
The present invention does not address these aspects of ACL reconstruction, but instead addresses the problem of securely anchoring the graft ligament in the bone tunnels while properly tensioning the ligament so as to provide support for the joint.
The prior art also addresses the concerns of properly anchoring and tensioning the graft ligament. However, the prior art known to the inventor does not provide a fully satisfactory anchor mechanism whereby both ends of the graft can be anchored in opposed tunnels in the tibia and femur, followed by final adjustment of the ligament tension. That is, preferably the anchors (or other attachment means employed) at both ends of the graft ligament would first be secured in their ultimate positions, followed by final adjustment of the ligament tension, in order to provide proper joint articulation. To the limited extent the prior art provides this capability (see the discussion of Johnson U.S. Pat. No. 5,562,668 below), the anchor structures known are undesirably complex, bulky, and hard to use properly.
More specifically, a common prior art ACL replacement practice is described in U.S. Pat. No. 5,306,301 to Graf. A flat planar ligament anchor is first attached to the femur end of the graft ligament, and is passed upwardly from below, so as to pass entirely through bone tunnels formed in the tibia and in the femur; after the planar anchor exits the proximal end of the bore, it is turned so as to bear against the outer surface of the femur. The opposite end of the graft is then fixed to the tibia. No adjustment of the ligament tension is possible after the ends of the ligament graft are fixed.
This technique requires that the overall length of the assembly be determined accurately before the graft is fabricated and secured to the tibia and femur. A difference in the ligament length of as little as a few millimeters is critical in provision of correct joint articulation. However, measurements of this accuracy are very difficult to determine in advance, as there are many variables involved, including the relative depth to which the anchors will be inserted into the bone tunnels, and the working length of the graft ligament, which in turn will vary depending on the degree of tightness with which the ligament graft is sutured to the anchor(s), the degree of stretch in the ligament itself, and so forth. It would be far more satisfactory if the surgeon could simply fabricate the graft ligament to an approximate overall dimension, anchor both ends in their final positions, and then make final tension adjustments. This ability would simplify the surgical procedure and yield better joint articulation after repair.
As indicated above, U.S. Pat. No. 5,562,668 to Johnson teaches a tensioning device for ligament grafts. At least one end of the graft is fixed to a carrier having a screw-threaded cylindrical member extending toward the outer surface of the joint. The carrier is received by a nut in turn received within a thimble. After the carrier is threaded into the nut, a process which would appear difficult in practice, the nut can be turned further, drawing the carrier further into the thimble. The nut can only be turned using a special tensioning key, which must be hollow in order to pass a wire needed to make the initial assembly of the carrier to the nut.
While the Johnson structure would permit adjustment of the tension on the ligament after seating of the thimbles in the bone tunnels, the degree of adjustment provided is constrained by the linear extent of the thread formed on the carrier, in turn requiring relatively exacting measurement of the overall distance between the anchoring points, and necessitating that the length of the ligament be controlled to correspond to this distance, complicating the procedure. The Johnson assembly also includes a relatively large number of parts, requires a special tool, requires a relatively large-diameter bore in the bone to receive the carrier and thimble, and takes up a significant fraction of the distance between the anchors, reducing the overall length of the ligament itself.
Rosenberg U.S. Pat. No. 5,152,790 shows a relatively complex three-component anchor assembly for ACL reconstruction. A first of Rosenberg's components includes a shank having threads formed on its outer surf ace for engaging the bone, and having a smooth internal bore. Torque is transmitted to the first component by a second component having a bore with a cross-section suitable for receiving torque from an associated driver. The second component is laser welded or otherwise bonded to the first component in order that a third component, to which the ligament is affixed, can rotate with respect to the first and second components. In this way, the ligament to be fixed by Rosenberg's device is not twisted as the first threaded component is drawn into a bore in a bone by torque exerted on the bore of the second component.
Rosenberg's anchor can thus be threaded into a bore in a bone, but there is no separate adjustment provided for the tension on the ligament. For example, if the ligament is fully tensioned before the threaded component is seated properly, the procedure must be repeated. Of course, the other end of the ligament could be affixed only after the anchor attached to the first had been seated, but this would not allow tension adjustment after anchor securing, as desired. Rosenberg's anchor is also excessively complex and bulky.
Other prior art generally relevant to this invention includes U.S. Pat. No. 4,870,957 to Goble, disclosing tubular threaded anchors for insertion into bone tunnels, followed by insertion of snap-fitting securing members from the inside of the joint. Not only would this insertion step be rather difficult to perform, the tension adjustment possible thereafter would be constrained by the degree to which the anchors could be moved in the bone tunnels without disturbing their secure seating.
U.S. Pat. No. 4,772,286 to Goble (now Reissue Pat. No. 34,293) also discloses several embodiments of methods and anchor structures for ACL replacement. The anchors shown in FIGS. 2-5 of Goble are expanding conical structures. It appears that although these anchors are threadedly attached to the ends of the ligament graft, their relative position cannot be adjusted after the anchors are secured in their final position; that is, the threaded members are provided simply to ensure secure fixation of the anchors, and do not allow for subsequent tension adjustment.
In a second embodiment, shown in several variations in FIGS. 6-11, Goble teaches attaching the graft to the femur by threading a screw fixed to one end of the graft into a tunnel drilled in the femur; the opposite end is secured in the tibia by turning a conical nut threaded over a fitting at the tibia end of the ligament against a seat formed in the tibia. This again requires the tension adjustment and tibial securing of the ligament end to be accomplished simultaneously; that is, the surgeon does not have independent control of the securing of the graft ligament in the tibia and of ligament tension.
U.S. Pat. No. 5,643,266 to Li also shows anchors for ACL replacement or similar procedures involving expanding anchors. In Li, the tension on the ligament must be adjusted before the anchors are secured in place. See col. 6, lines 11-24. Hence the ligament tension may vary as the anchors are expanded and secured.
Treace U.S. Pat. No. 3,953,896 shows a prosthetic ligament assembly including opposed conical threaded nut members for securing the ends of a prosthetic ligament in bone tunnels, and sleeves for protecting the ligament against abrasion. Treace mentions (col. 4, line 48) that the tension on the ligament is adjusted by turning the nut members; it appears that the fit of the nut members on the bone tunnels would substantially limit the degree of adjustment provided.
Other patents generally relevant to the subject matter of this application include Greenfield U.S. Pat. No. 5,584,835, showing a device for affixing tissue to bone. A threaded bone anchor is first threaded into the bone; the soft tissue is then sutured to a suture anchor. The outer surface of the suture anchor and a recess in the bone anchor are provided with cooperating asymmetrical teeth, so that the suture anchor can readily be inserted into but is securely retained by the bone anchor. No provision is made for adjustment of tension in a soft-tissue structure thus affixed to bone.
U.S. Pat. No. 5,350,399 to Erlebacher shows a structure for sealing puncture wounds in blood vessels and the like wherein an intra-arterial occluder and an extra-arterial occluder are drawn toward and secured to one another by a sawtooth-shaped guide extending from the intra-arterial occluder, through the wound, and over which the extra-arterial occluder is placed; when the two are drawn together, the sawteeth on the guide prevent them from slipping apart. A tool is provided for drawing the guide out through the extra-arterial occluder while holding the latter in position.
Patents showing anchors for securing ligament ends and other tissue structure to bone that do not provide subsequent adjustment of tension include Morgan U.S. Pat. No. 5,603,716; Beck U.S. Pat. No. 5,632,748; Thein U.S. Pat. No. 5,356,435; Steininger U.S. Pat. No. 5,425,767; Silvestrini U.S. Pat. No. 4,708,132; Parr U.S. Pat. No. 4,744,793; Coleman U.S. Pat. No. 5,645,547; Goble U.S. Pat. No. 4,927,421; and others.

Anchor assembly and method for securing ligaments to bone


A fluoride-free continuous casting mold flux for ultralow carbon steel, comprising the following components in weight percentage: 3-10% of Na2O, 0-3% of Li2O, 3-8% of MgO, 5-15% of MnO, 0-8% of BaO, 4-12% of Al2O3, and impurities with a content of no more than 2%, the balance being CaO and SiO2, wherein the ratio of CaO/SiO2 is 0.8-1.3; the raw materials are mixed and then pre-melted; the pre-melted mold flux requires micro-adjusting according to the component deviation, and the ratio of the pre-melted material is not lower than 70%; then a carbonaceous material of 1-3% by the total weight of the mold flux is added and mixed so as to obtain the finished product mold flux. Said mold flux has a melting point of 1100-1200° C. and a viscosity of 0.2-0.6 Pa·s at 1300° C. A method for preparing a mold flux comprising the following steps: mixing raw materials, pre-melting to obtain a pre-melt; then continuously supplementing raw materials into the pre-melt to obtain a substrate with a desired composition; then adding a carbonaceous material to the substrate and mixing so as to obtain said mold flux. This mold flux is a boron-free and fluoride-free mold flux, can effectively reduce the inclusion defect of blank casting and increase the yield of blank casting.

A continuous casting mold flux is a powdery or granular auxiliary material used in steel making for covering the molten steel surface in a crystallizer of a conticaster. Due to high temperature of the molten steel, the mold flux comprises a solid layer and a liquid layer, wherein the molten layer is immediately adjacent to the molten steel, and the part of the mold flux above the molten layer remains in its original granular or powder form so as to achieve good insulation and thus preventing the molten steel surface from solidifying. On the other hand, due to the periodic vibration of the crystallizer, the molten layer flows continuously into a crevice between a copper plate of the crystallizer and an initial shell of the molten steel to lubricate the relative movement between the shell and the copper plate, such that good surface quality of a cast slab is guaranteed. In addition, the molten layer also has the functions of absorbing nonmetal inclusions ascending in the molten steel and purifying the molten steel. Generally, the mold flux film flowing into the crevice between the copper plate of the crystallizer and the shell is only 1-2 mm. One side of the film that is adjacent to the copper plate is in solid phase, while the other side adjacent to the shell is still in liquid phase. The liquid phase has a function of lubrication. The solid phase has good control over the capability of the copper plate of the crystallizer in cooling the shell, such that the cooling rate of the molten steel may be regulated and the effect in controlling heat transfer can be achieved. Hence, a mold flux is the last process technique for controlling the surface quality of a cast slab in steel making A mold flux with inappropriate properties may induce surface deficiencies such as flux inclusions, cracks, etc. in the cast slab. More seriously, the shell may even break and an accident of steel leakage may be incurred. Therefore, a mold flux is an important means for guaranteeing successful proceeding of a continuous casting process and surface quality of a cast slab.
Generally, a casting mold flux comprises mainly a binary system of CaO and SiO2, accompanied with fusion aids such as CaF2, Na2O, Li2O and the like to lower melting point and viscosity of the binary system of CaO and SiO2, as well as a small amount of such components as Al2O3, MgO, MnO, Fe2O3 and the like to obtain desirable metallurgical properties. Since the melting point of a mold flux is about 400° C. lower than the temperature of molten steel, an amount of carbonaceous material must be added to allow slow melting of the mold flux having a relatively low melting point on the surface of molten steel. The carbonaceous material, having a very high melting point, can stop agglomeration of liquid drops of the mold flux effectively, and thus retard melting of the mold flux. Among these components of the mold flux, the ratio of CaO to SiO2 (i.e. CaO/SiO2, referred to as basicity hereafter) and the amount of F may be regulated to achieve an effective control over the precipitation rate of cuspidate (3CaO.2SiO2.CaF2), in order to fulfill the purpose of regulating the crystallization behavior of the mold flux reasonably. Crystallization behavior is the most effective means for the mold flux to control heat transferring properties. Stronger crystallization behavior results in higher thermal resistance of the mold flux and lower heat transfer intensity. Fully vitrified mold flux has the minimum thermal resistance and the maximum heat transfer intensity. For low-carbon steel, ultralow-carbon steel and those types of steel having poor thermal conductivity (e.g. silicon steel, etc.), in order to improve the cooling of casting slabs, crystallization of the mold flux is undesirable. Hence the amount of F is generally low, specifically at about 3-5%. However, for peritectic steel and those types of steel containing crack-sensitive elements, if the cooling of molten steel in a crystallizer is uneven or too fast, the initial shell will break readily at weak locations under various stresses, resulting in longitudinal cracks. For these types of steel, the mold flux must have a very high crystallization behavior to effect slow cooling and inhibition of cracking. In these circumstances, the content of F in the mold flux is usually up to 8-10%. It can be seen that F contained in a mold flux not only acts to lower melting point and viscosity, but also plays an important role in improving crystallization. Thus, it is a very important component in a mold flux.
It is well known that F is a toxic element whose harm to human beings, animals and plants is at a level 20 times higher than the harm level of sulfur dioxide. Due to the high working temperature of the mold flux, which is generally at about 1500° C., a large quantity of environmentally harmful fluoride gases (including SiF4, HF, NaF, AlF3, etc.) are produced in the melting process. Fluorides, especially HF, in the air, are among the common air pollutants. Additionally, after exiting the crystallizer, the molten mold flux at high temperature contacts secondary cooling water sprayed on a cast slab at high speed, and they interact with each other to undergo the following reaction:2F—+H2O═O2-+2HF.
When HF dissolves in water, the fluoride ion concentration in the secondary cooling water and pH of the secondary cooling water are increased. As the secondary cooling water is recycled, the fluoride ions will be further enriched, and pH will be further increased. The increase of the fluoride ion concentration and pH of the secondary cooling water speeds up the corrosion of the continuous casting equipment greatly, leading to higher maintenance fee of the equipment, higher difficulty and neutralizer cost in treatment of the recycling water, and higher burden of sewage discharge.
In view of the above problems concerning a F containing flux, both domestic and foreign metallurgists devote themselves actively to development of environmentally friendly mold fluxes that are free of F. Currently, a relatively feasible solution is replacement of F with B2O3 which is batched reasonably with such components as Na2O, Li2O and the like to fulfil the purpose of regulating the melting property of the mold flux. See, for example, CN201010110275.2, CN200510065382, CN201110037710.8, JP2001205402, etc. However, the melting point of B2O3 is only on the order of 450° C., far lower than those of the other components of the mold flux. Hence, the softening temperature of the solid phase of the boron-containing mold flux is apparently lower. Consequently, the proportion of the solid phase in the flux film located in the crevice between the copper plate of the crystallizer and the shell is rather low, resulting in lowered thermal resistance of the flux film and rather high heat flow in the crystallizer. In addition, B2O3 contained in the mold flux tends to form a network structure, which inhibits crystallization. As a result, the solid phase has a vitreous structure. A vitreous solid phase has lower thermal resistance than a crystalline solid phase. Therefore, a boron-containing flux has lower thermal resistance than a traditional fluoride-containing flux. Once the excessively high heat flow exceeds the limit designed for a caster, not only the service life of the crystallizer will be affected, but the risk of sticking breakout will be increased. For ultralow carbon steel, the principal quality problem of a cast slab is the deficiency of flux inclusions due to embedding of molten mold flux in molten steel. For minimizing the possibility of embedding of the molten flux, one of the most effective measures is to promote separation of the mold flux by increasing the surface tension of the flux. However, B2O3 is a component capable of decreasing the surface tension of the molten flux. Hence, with regard to mold flux used for ultralow carbon steel, B2O3 is a component that must be controlled. The mold fluxes designed in patent application CN200810233072.5 and patent CN03117824.3 have an unduly high crystallization behavior and are suitable for crack-sensitive steel such as peritectic steel, etc. Patent applications JP2000158107 and JP2000169136 have proposed mold fluxes having high melting points and high viscosity, which are mainly used for billet continuous casting. In patent application JP2002096146, the MgO content is too high, such that Mg—Al spinel having a melting point higher than 2000° C. tends to form and worsen lubrication badly after the molten flux absorbs a certain amount of Al2O3.

Fluoride-free continuous casting mold flux for ultralow-carbon steel


A digital still video camera including a camera processor which processes image data of a subject, a recording processor which generates recording data based on the processed image data, a recording controller which controls recording of the recording data to a recording medium, a memory which stores image data processed by the camera processor and recording data recorded in the recording medium, a control device which controls the camera processor, the recording processor, and the recording controller, and an evacuating/writing device which interrupts control by the control device and evacuates/writes the recorded recording data between the recording medium and the memory.

1. Field of the Invention
This invention generally relates to a digital still video camera, and more particularly relates to a digital still video camera for recording image data of a subject to a recording medium, for example, a flash memory card.
2. Discussion of the Background
FIG. 3 is a block diagram of a conventional digital still video camera including a video processing unit formed by a lens 1, a CCD (Charge Coupled Device) 2, a pre-processing circuit 3, an A/D (Analog/Digital) converter 4, a memory 5, and a camera processor 6 and having video signal output 19.
The conventional camera of FIG. 3 further includes an encoder/decoder 7, a FIFO (First in First Out) circuit 8, a MCC (Memory Card Controller) 9 and a flash memory card 10. The FIFO circuit 8 is connected to MCC 9 and inputs data to and from the MCC 9. The flash memory card 10 is detachably connected to MCC 9, and memorizes recording data controlled by the MCC 9. A CPU 11 controls the camera processor 6, the encoder/decoder 7, and the MCC 9 (including FIFO circuit 8) using the bus 18.
Audio is input via a microphone 21, a first AMP (first amplifier) 12 which amplifies voice data input by the microphone, an A/D (Analog/Digital converter) 13 connected to the first AMP 12, an ADPCM (Adaptive Differential Pulse Code Modulator) 14 connected to A/D 13 and the MCC 9, a D/A (Digital/Analog) converter 15 connected to the ADPCM 14, a second AMP (second amplifier) 16 connected to the D/A 15, and output to an audio output 20 connected to second AMP 16.
A subject is image-formatted on the CCD 2 through the lens 1. The image formatted by CCD 2 is processed (for example gain control) in the pre-processing circuit 3, and converted to digital image data in the A/D converter 4. In the camera processor 6, the digital image data are processed in a matrix process and a raster block (8.times.8) process. In the encoder/decoder 7, the processed digital image data are encoded. The memory is used as an image memory in producing a brightness signal or a color signal and processing a matrix based on the digital image data input from the A/D converter 4, or is used as a memory for the raster block process in encoding or decoding. The encoded digital image data are input to the FIFO circuit 8 and recorded in the flash memory card 10 by MCC 9 as recorded image data.
A voice input signal is converted to an electrical signal by the microphone 21. In the first AMP 12, the electrical signal is amplified. In the A/D converter 13, the amplified electrical signal is converted to digital voice data, and in the ADPCM 14, converted digital voice data are encoded. The encoded digital voice data are recorded in the flash memory card 10 by MCC 9 as recorded voice data.
In case of reproducing recorded image data, the recorded image data are input to the FIFO circuit 8 by MCC 9 and decoded in the encoder/decoder 7. The decoded recorded image data are input and converted to a video signal in the camera processor 6, and output through the video signal output 19.
In case of reproducing the recorded voice data, the recorded voice data are input and decoded in the ADPCM 14. The decoded recorded voice data are input and converted to an analogue audio signal in the D/A converter 15, and output through the audio output 20.
However, in such a digital still video camera of the prior art, the flash memory card 10 has difficulty to rewrite data by 1 byte because an erasing unit of the flash memory card 10 is larger than 1 byte. The digital still video camera of prior art needs an optional memory which has larger capacity than the capacity of the erasing unit of the flash memory card 10. The necessity for the optional memory increases the size and cost of the conventional digital still video camera.


A surgical operation apparatus of this invention includes an operation sheath having a cavity securing portion that is inserted into vital tissue through the skin to secure a working cavity for a surgical operation in the body, and a sheet member that allows an operation tool to be inserted from outside the body into the cavity. The operation sheath is guided into the vital tissue by guide tools such as a dilator, a soft tube, and a mandrin.

The present invention relates to a surgical operation system and method for percutaneously securing a cavity as a working space for a surgical operation in the body by using a cavity securing tool.
Recently, increasing numbers of operations in cavities in body tissues using endoscopes have been performed. The merit of such an operation is that a low invasive operation can be performed because a treatment is made with an approach to a cavity in the body through a small incision as compared with so-called open surgery in which a treatment is made with an approach to a target treatment site after a large incision is made in the tissue. However, one of the problems in endoscopic operations is that it is difficult to secure a good site of operation in the body.
For example, percutaneous lumbar discectomy is generally performed as follows. A median incision is made in the back of the patient to expose the back muscle. The back muscle is incised, and the incision in the back muscle is spread open by using a pushing element, thereby exposing the lumbar vertebrae. Part of the lamina of vertebral arch is removed to expose the yellow ligament having the nerve root. The yellow ligament is then incised, and the dura mater located therebelow is shifted to one side. The evagination portion of the hernia located on the rear side of the dura mater is removed. In a general conventional operation in which a median incision is made in the back of the patient, and a site of operation is exposed by using a pushing element, a lumbago occurs after the operation because a large incision is made in the dorsolumbar muscle, the dorsolumbar is separated from the bones, or the dorsolumbar muscle is pushed for a long period of time or with a strong force. In addition, pushing may cause unrecoverable damage to the back muscle.
Under the circumstances, as disclosed in U.S. Pat. No. 5,439,464, a technique of performing a back operation has been proposed. According to this technique, a plurality of cannulas are inserted from the back of the patient to positions near the spine. Physiological saline is then injected to a portion near the spine through one of the canulas to secure a working space with the pressure of the physiological saline. A hard mirror and a treatment tool are introduced through the remaining cannulas. After this process, an endoscopic operation is performed.
According to a general technique based on a so-called open surgery, an incision is made in the back to expose the back muscle, and the incision in the back muscle is spread open by a pushing element, thereby exposing the lumbar vertebrae. In this operation, pushing causes great damage to the back muscle. This may cause unrecoverable damage to the back muscle. In addition, an incision itself may cause great damage to the back muscle and the like.
In the technique of using a plurality of cannulas as in U.S. Pat. No. 5,439,464, damage to the back muscle by an incision and pushing is relatively small, but a sufficient visual field and a sufficient working space cannot be obtained.

Surgical operation system and method of securing working space for surgical operation in body


A method, apparatus, and system for performing a Location SLO check based on a location scatter table is disclosed. A location scatter table is maintained, the location scatter table indicative of updated geographical location distribution of all backups of all assets. A Location Service Level Objective (SLO) associated with a first asset is determined, the Location SLO associated with the first asset specifying one or more allowed locations where backups of the first asset are permitted to be located. All locations where at least one backup of the first asset is located are determined. A Location SLO check for the first asset is performed, wherein the Location SLO check passes when all the locations where at least one backup of the first asset is located fall within the allowed locations specified by the Location SLO.

EMC Enterprise Copy Data Management (eCDM) is used to protect enterprise assets such as virtual machine (VM) images, databases, and other files. It creates and manages backups of the assets. Backups are created regularly for assets, and may be placed at different geographical locations (e.g., different data centers). For example, a VM may be hosted in a datacenter in Seattle, but its backups may be stored in datacenters in Boston and Los Angeles to enhance the Disaster Recovery capability.
A security manager may create Service Level Agreements (SLAs), and associate them with assets. If an asset has an SLA attached thereto, all its backups need to comply with the corresponding SLA rules; otherwise, a warning may be issued. An SLA may comprise a number of Service Level Objectives (SLOs). One type of SLOs are known as Location SLOs. A Location SLO comprises a list of allowed locations. If any backup of an asset to which the Location SLO applies is placed in a location not on the list of allowed locations, the Location SLO check should fail.
For example, a Location SLO of [Shanghai, Beijing] applies to the asset with the asset identifier (ID) "asset-1." Accordingly, all backups of the asset with the asset ID of "asset-1" should be placed in either Shanghai or Beijing. If a backup of the asset is placed in Chengdu, the Location SLO check fails. Typically, SLA checks are performed every day, during which all SLOs are checked for all protected assets to which SLAs are attached.

Efficient way to perform location SLO validation


A coating composition which is capable of curing at ambient temperature to form a coating comprises (A) an anhydride-functional polymer containing at least two cyclic carboxylic acid anhydride groups per molecule and (B) an amine-functional polymer and is characterized in that the amine-functional polymer (B) contains at least two secondary amine groups per molecule, the polymer (B) being substantially free from hydroxy and ether oxygen atoms and amine nitrogen atoms in the alpha and beta positions with respect to the amine nitrogen atoms, and the carbon atoms directly bonded to the amine nitrogen atoms not being tertiary carbon atoms.

U.S. Pat. No. 4,452,948 describes a coating composition suitable for use as a glossy pigmented coating for a rigid substrate, particularly where hardening of the coating at ambient temperatures is required, for example as a vehicle refinishing paint. The coating composition comprises a hydroxy component having at least two free hydroxyl groups per molecule and an anhydride component having at least two cyclic carboxylic acid anhydride groups per molecule, at least one of these components being a film-forming polymer. The composition also includes a catalytically effective amount of amine groups for accelerating the curing reaction between the hydroxyl groups and the anhydride groups. The amine groups are preferably incorporated in the molecule of the hydroxy component. Tertiary amine groups are preferred although certain secondary amine groups, for example those containing tertiary alkyl groups such as polymerised units of t-butylaminoethyl methacrylate, can be used.
European Patent 73022 describes an anhydride-functional polyester and claims its use as a hardener for compounds having free epoxide, amine or hydroxyl groups. European Patent Application 282184 describes a grease-compatible, plasticiser-extended encapsulant for spliced electrical or optical cable comprising an anhydride-functionalised composition and a crosslinking agent such as a polyol, polyamine or polythiol.
European Patent Application 259172 describes a coating composition comprising an anhydride polymer containing at least two cyclic carboxylic acid anhydride groups and a polymer containing at least two functional groups reactive with anhydride groups. These reactive groups are selected from hydroxyalkylamino, hydroxyalkoxyalkylamino, hydroxy-substituted acyloxyalkylamino, hydroxy-substituted polyacyloxyalkylamino, mercaptoalkylamino and oxazolidino groups. One of the polymers comprises a flexible polymer chain selected from polyether, polyester, silicone, diene polymer, hydrogenated diene polymer, polyurethane, polyisobutylene and polyacrylate chains. The functional groups characteristic of that polymer are each present as a terminal group at the end of a flexible polymer chain. The cured coatings have increased resistance to impact and abrasion. The hydroxyalkylamino groups are preferably tertiary amino groups but can be secondary amino groups formed for example from the reaction of a primary amino group with an epoxide or from the reaction of a carboxy-tipped polymer with N-hydroxyethyl imine.


In implementations of a pressure lock retention fastener, the fastener assembly includes an insert sized for insertion into a fastener hole in a first panel. The fastener assembly has a threaded collet sized to slide in the insert and has expandable flanges that extend below the insert. The expandable flanges are sized for insertion into an aligned hole in a second panel. The fastener assembly also includes a screw installable through the insert to engage the threaded collet. The screw exerts a force that pushes the expandable flanges outward as screw rotation drives the screw into the threaded collet, and ridge locks of the expandable flanges seat up against the second panel effective to fasten the panels together. In implementations, a plate is installable between the panels with slotted holes having anti-rotation tabs that prevent a fastener assembly from spinning in the panel holes.

Fastening devices are generally designed to fasten together at least two items or structures, such as to attach a panel to a support structure, or to attach two components of any type of device, structure, or system together. For fasteners that are designed to be inserted through a hole, such as through pre-drilled holes in two panel structures that are being fastened together, access to both sides of the panels is needed to insert a first part of the fastener from one side of the panels and to attach a second part of the fastener from the other side of the panels (or from the other side of one panel). However, there are many situations in manufacturing, construction, and assembly where both sides of two items being fastened together are not accessible for the types of fasteners needed for the application.


The subject matter disclosed herein relates to a system and method for determining navigation instructions in a navigation environment. A location estimate may be determined for a mobile device within an indoor pedestrian navigation environment. A user input indicating one or more destinations within the indoor pedestrian navigation environment may be received. A lowest cost path from the location estimate to the one or more destinations may be determined based at least in part on an expected number of navigation instructions associated with the lowest cost path. Such a lowest cost path may be presented to a user.

1. Field
The subject matter disclosed herein relates to reduction of a number of navigation instructions presented to a user within an indoor navigation environment.
2. Information
Navigation systems are becoming more and more pervasive in today's market. A navigation system may be utilized to determine a route from a first location to a second location. In some navigation systems, a user may enter a start location and an end location into a mapping application, such as one of the different mapping applications commonly used on Internet websites.
Such navigation systems may be utilized by a person who is unfamiliar with a certain area and desires directions to a particular location. In the event that a destination is along a straight-line path from a user's starting location, directions may be provided to a user that are relatively easy to follow. However, in some scenarios, a user may request directions to a location that is not along a straight-line path and may require some changes in direction to arrive at a particular destination. Ease of use is a concern for navigation systems because a user is more likely to have difficulty following directions that are relatively complicated such as those involving several changes in direction along a path.

Method and apparatus for reducing instructions in an indoor navigation environment


A regulated length take-up device characterized by its substantially reduced width to be compact and simple structure, offering accurate regulated length take-up operation. A rotating lever is connected to the shaft of a take-up roll via a one-way clutch. Connected to the rotating lever is a cylinder mechanism which allows the take-up roll to rotate for the take-up operation along with the cylinder pull-in action. A sensor lever 32 capable of oscillating in accordance with variations in the take-up diameter of the take-up roll, is disposed in a manner that the orbit of the oscillation of the sensor lever agrees with the direction of the stroke of the cylinder mechanism. Along with a stopper disposed on the sensor lever to face the restoring action of the rotating lever, a cam curvature portion is formed on the rotating lever so that the cylinder stroke is constrained to keep constant the take-up length at every position over the orbit of the stopper regardless of variations of the take-up diameter of the take-up roll.

The present invention is directed to a regulated length take-up device, and, more particularly, is directed to the appropriately structured, regulated length take-up device which is suitably applied to an instrument which feeds continually washing cloth by a regulated length for the purpose of blanket cylinder washing operation in a printing machine.
In offset printing, a blanket cylinder is usually washed in order to remove residual inks and paper powder each time a predetermined amount of printed sheets is outputted. When a washing apparatus wipes the blanket cylinder by means of washing cloth, the washing cloth fed by a washing cloth feeder roller travels past a pressure block and is taken up by a take-up roll. The take-up roll continually takes up the washing cloth by a regulated length.
In the prior art regulated length take-up device described above, consideration is given to taking up a regulated length of the cloth, aimed at its efficient use. Variations of the take-up diameter of the take-up roll make it impossible to achieve regulated length take-up. Various techniques have been devised to cope with this. For example, a technique disclosed by Japanese Unexamined Patent Application No. 1-314173 (disclosed in Dec. 19, 1989) has, on a take-up roll shaft, a lever which is urged by an air cylinder to carry out take-up operation. Disposed on the other side of the lever, i.e., opposed to the air cylinder, is a stopper integrated with a detector block which moves in response to variations of the take-up diameter of the take-up roll, in a manner that the stopper is capable of being in contact with the lever; the washing cloth is taken up until the lever driven by the air cylinder contacts the stopper. In the apparatus proposed by the disclosure, the contact face of the lever against the stopper has a curvature configuration which allows the stroke of the air cylinder to be controlled in a manner that a fixed take-up length is achieved at each position of the stopper which shifts in response to variations of the take-up diameter of the take-up roll. The disclosure claims that the regulated length take-up operation is achieved by varying the cylinder stroke in accordance with the change of the take-up roll diameter.
Such a prior art regulated length take-up device described as above fails to accurately measure the take-up roll diameter under slippage and friction which incur between the rod of the air cylinder and the take-up lever, and between a stopper pin and its pin receiver, when the air cylinder drives the lever. The air cylinder, the take-up lever driven by the air cylinder and the diameter detector block share the common line of action (a straight line), and this line is perpendicular to the longitudinal axis of the take-up roll. The overall width of the take-up device of this kind is usually, mainly determined by the layout of both the washing cloth feeder roll and the take-up roll; if the structure of the air cylinder extends substantially the width of the take-up roll, however, the width of the device must be wide enough to accommodate the required stroke of the cylinder.


A rate responsive cardiac pacemaker for providing an optimized pacing rate of stimulation pulses as a function of at least one selected rate control parameter. Each rate control parameter has a value which varies as a function of changes in a patient's physiologic demand and includes a sensor system for sensing the rate control parameter value and for providing a sensor output representative thereof. The cardiac pacemaker also includes a rate response defining means for deriving desired pacing rates as a function of the sensor output, an achievement monitoring means that has a predetermined achievement criterion (primary criterion), for monitoring the relationship between the derived pacing rates and the achievement criterion over an optimization period, and either one of Average Activity level or Average Activity Difference level monitoring means that has a corresponding predetermined minimum and a predetermined maximum Average Activity level or Average Activity Difference level (secondary criterion), for monitoring the relationship between the derived pacing rates and the secondary criterion over an optimization period. Another optimization function is provided by adjusting a sensor weighting value which weights or regulates the relative contribution each sensor's derived desired pacing rates will contribute toward the pacemaker-derived optimized pacing rates.

1. Field of the Invention
The present invention generally relates to cardiac pacemakers, and more particularly, pertains to cardiac pacemakers of the type which measure physiologic or metabolic requirements and vary the rate of the pacemaker in accordance therewith.
2. Description of the Prior Art
Early cardiac pacemakers provided a fixed-rate stimulation pulse generator that could be reset on demand by sensed atrial and/or ventricular depolarization. Modern pacemakers include complex stimulation pulse generators, sense amplifiers and leads which can be configured or programmed to operate in single or dual chamber modes of operation, delivering pacing stimuli to the atrium and/or ventricle at fixed rates or rates that vary between an upper rate limit and a lower rate limit.
In recent years, single and dual chamber pacemakers have been developed which measure rate control parameters (RCP's) which are directly or indirectly related to metabolic requirements (e.g., demand for oxygenated blood) and vary the pacing rate in response to such measured RCP'S. Such RCP's include, for example, QT interval evoked response, physical activity of the body, right ventricular blood pressure and the change of right ventricular blood pressure over time, venous blood temperature, venous blood oxygen saturation, respiration rate, minute ventilation, and various pre and post-systolic time intervals measured by impedance or pressure sensing within the right ventricle of the heart. Such RCP-measuring, sensor-driven pacemakers have been developed for the purpose of restoring rate response to exercise or other physiological stresses in patients lacking the ability to increase rate adequately by exertion.
In general, a rate responsive pacemaker includes a sensor which produces a sensor output representative of a selected RCP, such sensor output varying between a maximum sensor output level and a minimum sensor output level ("Sensor Output"). The pacemaker provides a pacing ("Pacing Rate") which typically varies as a linear or monotonic function ("f") of the sensor output between a selectable lower pacing rate ("Lower Rate") and upper pacing rate ("Upper Rate"). Function f has a selectable slope (i.e., Pacing Rate change/Sensor Output change) adjustable by means of an external programmer in conjunction with the Lower and Upper Rates. Thus, the Pacing Rate typically provided is equal to the pre-selected Lower Rate plus an increment which is a function of the measured Sensor Output, as follows: EQU Pacing Rate=Lower Rate+f (Sensor Output).
A human's heart rate, however, is normally controlled by a complex set of inputs to the autonomic nervous system. Consequently, no single type of sensor has been found to be entirely satisfactory for controlling rate response functions. Some of the shortcomings of single-sensor, rate responsive pacemakers, for example, can include: (1) long-term sensor instability, such as from degradation; (2) long-term changes in correlation between sensor output and its RCP being measured, due to physiologic changes in the patient, such as biologic/sensor interface changes due to tissue changes; (3) changes in sensor sensitivity; and (4) the need for frequent re-programming to accommodate the foregoing problems, as they are encountered.
Various efforts have consequently been made to develop a multiple-sensor pacemaker which is capable of varying its rate as a function of more than one type of measured RCP. Unfortunately, implementation of such multiple sensor-driven rate response concepts has proven to be very difficult and not entirely satisfactory. In addition to those problems listed above as to single-sensor pacemakers, other problems which are typically encountered include: (1) differences between sensors in long-term stability; (2) differences between sensors in immunity to noise; (3) differences in response time to changing metabolic conditions; (4) differences between sensors in correlation between each sensor output and its RCP being measured; (5) time response lags during rate response optimization process; and (6) complex set-up procedures, including the need for frequent re-programming.
Thus, a need exists for a rate response pacemaker which will better accommodate the above-identified problems, preferably in a self-adaptive manner, in the context of a single-sensor or multiple-sensor pacemaker. A pacemaker which better accommodates the above -identified problems is disclosed in U.S. patent application Ser. No. 07/567,476, filed Aug. 14, 1990, entitled "Optimization For Rate Responsive Cardiac Pacemaker". The '476 application discloses the concept of meeting specific achievement criteria over certain time periods, then adjusting the rate response curve based on meeting, under-achieving, or over-achieving the criteria. The preferred time period for rate response optimization was 24 hours, although any time period could be selected. In the logic of the '476 implementation, the rate response optimization will tend to have a phase lag. A patient who is inactive for 24 hours would have their rate response adjusted upward. Similarly, a patient who had a 24 hour period of unusually high activity would have their rate response curve adjusted downward. Either of the above responses could be inappropriate for the next 24 hour period. For example, the inactive patient whose response was increased could have normal activity the next 24 hours and have too much rate response, and the patient who was more active and whose response was decreased could become normally active over the next 24 hours but generate too little rate response.
A need therefore exists for a method to compensate for the above scenario. The process of monitoring some indicator of pacemaker function over some specified time period, such as a 24 hour optimization period, then adjusting the pacemaker according to that indicator for the next period, implies that each 24 hour optimization period be "normal" or "typical". To assure that adjustments of pacemaker parameters are only done based on "normal" optimization periods, a secondary set of criteria are used. The Average Activity criteria or Average Activity Difference criteria are to assure the last 24 hours are "typical"; i.e., the mean Activity levels were comparable to several prior periods.

Rate responsive cardiac pacemaker and method for providing an optimized pacing rate which varies with a patient's physiologic demand


Air from a pressurizing pump is supplied to a plurality of ink jet heads through an air tank and a plurality of ink tanks, and head inner pressures of the respective ink jet heads are raised. Accordingly, ink liquids are discharged from the respective ink jet heads. Thereafter, the desired ink tank among the respective ink tanks is allowed to communicate with the air tank. Moreover, the desired ink tank and at least one or more air tanks are opened to the atmosphere. In consequence, pressure in the desired ink tank is averaged.

1. Field of the Invention
The present invention relates to a method of maintenance for an ink jet head in a case where ink of each color is spouted from a plurality of ink jet heads to thereby form an image on an image forming medium, and an image forming apparatus using this method.
2. Description of the Related Art
As shown in FIG. 16, a plurality of ink jet heads 1 are used in an ink jet system image forming apparatus. Each ink jet head 1 has a nozzle plate 3 and piezoelectric elements (PZT) 4. A plurality of nozzles 2 are formed in the nozzle plate 3. A piezoelectric element 4 is disposed for each of the nozzles 2. Each ink jet head 1 has an ink chamber 5 formed by the piezoelectric element 4 for each nozzle 2.
Respective ink jet heads 1 are disposed for the colors of black (K), cyan (C), magenta (M), and yellow (Y). Each ink chamber 5 of the ink jet head 1 is charged with each color of ink 6. When each piezoelectric element 4 is displaced/operated at an image forming time, the pressure in each ink chamber 5 rises. The ink 6 is spouted from each nozzle 2.
When a back pressure is applied to each ink chamber 5 in the ink jet head 1, a meniscus 7 is formed in each nozzle 2.
Additionally, when dust, dirt, air, degraded ink liquid and the like are mixed in the ink chamber 5, and deposits such as dust and dirt adhere to the nozzle 2 or the vicinity of the nozzle 2, the meniscus 7 collapses. Therefore, the amount of each ink 6 spouted from the nozzle 2 is not appropriate. A jet direction of the ink 6 changes. As a result, a high-quality image cannot be formed.
Therefore, maintenance for the ink jet head 1 is performed. For example, the following technique is described in Jpn. Pat. Appln. KOKAI Publication No. 2002-347260.
A predetermined nozzle in the ink jet head is sealed by sealing means such as a suction cap. The inside of the sealing means is sealed, and brought into a negative pressure state. In this state, the sealing means including the suction cap or the like is swept/moved with respect to the ink jet head. The sealing means including the suction cap sucks remaining ink in the nozzle. Accordingly, bubbles or foreign matter in the nozzles is discharged.
In the maintenance for the ink jet heads 1, the bubbles, foreign matter and the like in the nozzles 2 and the ink chambers 5 are discharged, collapsed meniscuses 7 are recovered, and generation of newly collapsed meniscuses 7 is prevented. When the sealing means brought into the negative pressure state is simply swept and moved as in the Jpn. Pat. Appln. KOKAI Publication No. 2002-347260, it is difficult to securely recover the meniscuses 7 in the nozzles 2 of the ink jet heads 1.
To solve the problem, in a constitution shown in FIG. 17, maintenance for ink jet heads 1k-1 to 1y-6 is performed for each color (K, C, M, Y).
The plurality of ink jet heads 1k-1 to 1y-6 are connected to distributors 10-1 to 10-4 for each color (K, C, M, Y). The respective distributors 10-1 to 10-4 are connected to ink tanks (sub-tanks) 12-1 to 12-4 via tubes 11-1 to 11-4.
The respective ink tanks 12-1 to 12-4 are charged with inks 6k, 6c, 6m, 6y of the respective colors. The respective ink tanks 12-1 to 12-4 are connected to atmosphere open tubes 13-1 to 13-4. The respective atmosphere open tubes 13-1 to 13-4 are provided with atmosphere open valves 14-1 to 14-4. It is to be noted that liquid level height positions of the respective inks 6k, 6c, 6m, 6y in the ink tanks 12-1 to 12-4, and height positions of the respective nozzles 2 of the ink jet heads 1k-1 to 1y-6 are set to a difference of elevation optimum for applying a back pressure to the respective ink chambers 5 of the ink jet heads 1k-1 to 1y-6 to thereby form the meniscuses 7 in the nozzles 2.
The ink tanks 12-1 to 12-4 are connected to air tanks 16-1 to 16-4 via communication tubes 15-1 to 15-4. The respective communication tubes 15-1 to 15-4 are provided with pressurizing valves 17-1 to 17-4. The ink tanks 12-1 to 12-4 are connected to ink bottles (not shown) of the respective colors. The inks 6k, 6c, 6m, 6y of the respective colors are supplied to the ink tanks 12-1 to 12-4 from the respective ink bottles.
The respective air tanks 16-1 to 16-4 are connected to pressurizing pumps 19-1 to 19-4 via pressurizing tubes 18-1 to 18-4.
Cleaning members 20k-1, 20k-2, 20k-6 are disposed for the ink jet heads 1k-1 to 1y-6. In FIG. 17, the only cleaning members 20k-1 to 20k-6 for the color K are shown in order to avoid laborious drawing.
The respective cleaning members 20k-1 to 20k-6 are connected to a suction pump 22 via a suction tube 21. The respective cleaning members (suction heads) 20k-1 to 20k-6 and suction nozzles for the other colors slide with respect to the ink jet heads 1k-1 to 1y-6.
Next, a maintenance operation will be described.
First, the respective atmosphere open valves 14-1 to 14-4 close. Moreover, the pressurizing valves 17-1 to 17-4 close.
Next, the respective pressurizing pumps 19-1 to 19-4 are driven. Air from the pressurizing pumps 19-1 to 19-4 is supplied to the air tanks 16-1 to 16-4 through the pressurizing tubes 18-1 to 18-4. At this time, since the pressurizing valves 17-1 to 17-4 are closed, pressures in the air tanks 16-1 to 16-4 rise.
When the pressures in the air tanks 16-1 to 16-4 reach predetermined pressures (pressures required for purging), the pressurizing valves 17-1 to 17-4 are opened. Accordingly, the purge pressures in the air tanks 16-1 to 16-4 are applied to the ink tanks 12-1 to 12-4 through the pressurizing valves 17-1 to 17-4. The pressures in the ink tanks 12-1 to 12-4 rise.
By the rising of the pressures, the respective inks 6k, 6c, 6m, 6y of the colors stored in the ink tanks 12-1 to 12-4 are supplied to the distributors 10-1 to 10-4 via the tubes 11-1 to 11-4. Furthermore, the inks 6k, 6c, 6m, 6y are supplied to the ink jet heads 1k-1 to 1y-6.
Accordingly, the respective inks 6k, 6c, 6m, 6y are discharged from the nozzles 2 of the ink jet heads 1k-1 to 1y-6. When the inks 6k, 6c, 6m, 6y are discharged, bubbles, foreign matter and the like in the nozzles 2 and the ink chambers 5 are discharged. The discharging of the bubbles, foreign matters and the like in the nozzles 2 and ink chambers 5 by the discharging of the inks 6k, 6c, 6m, 6y is referred to as purging.
Next, the respective atmosphere open valves 14-1 to 14-4 are opened. Accordingly, the pressures in the ink tanks 12-1 to 12-4 are reduced. At this time, when open/close timings of the atmosphere open valves 14-1 to 14-4 are controlled, pressure reduction in the ink tanks 12-1 to 12-4 is controlled. By this control, the pressures in the ink chambers 5 of the ink jet heads 1k-1 to 1y-6 are set to predetermined micro-positive pressures.
By the setting of the micro-positive pressures, the inks 6k, 6c, 6m, 6y are gradually discharged from the nozzles 2 of the ink jet heads 1k-1 to 1y-6. It is to be noted that even when the respective inks 6k, 6c, 6m, 6y are gradually discharged from the nozzles 2, the ink remains to such an extent that the ink does not drop onto the nozzle plate. This state is maintained before/after a sucking operation described later.
In this state, the respective cleaning members 20k-1 to 20k-6 are brought into contact with the nozzle plates 3 of the ink jet heads 1k-1 to 1y-6, and slid. Accordingly, the cleaning members 20k-1 to 20k-6 scrape and suck the inks 6k, 6c, 6m, 6y discharged to the nozzle plates 3 of the ink jet heads 1k-1 to 1y-6. Accordingly, the cleaning members 20k-1 to 20k-6 remove deposits adhering to the nozzle plates 3. To move the cleaning members 20k-1 to 20k-6 while removing the deposits from the nozzle plates 3 will be referred to as sucking.
Next, the atmosphere open valves 14-1 to 14-4 are opened. When the atmosphere open valves 14-1 to 14-4 are left in the open state, back pressures are applied in the ink chambers 5 of the ink jet heads 1k-1 to 1y-6. The meniscuses 7 are formed in the nozzles 2 of the ink jet heads 1k-1 to 1y-6.

Method of maintenance for ink jet head and image forming apparatus


A skeleton or frame for building a vehicular body of a cargo vehicle with a load bearing support system for supporting one or more levels of accessories to provide one or more additional levels of load bearing surfaces. The frame comprises at least two side portions comprising a plurality of longitudinally spaced sidewall posts and at least one transverse member connecting the two side frames for mounting various panels (e.g., a roof, floor, wall, door, window, sunroof, refrigerator unit, air conditioner unit, etc.) and accessories (e.g., a shelf, drawer, bin, cabinet, platform, cot, sliding rack, bucket, bench and the like).

The present invention relates generally to a vehicular body frame, more particularly, to a frame for building a vehicular body with a load bearing support system for use in cargo vehicles.
Although a large variety of box truck designs exist, they all include the common features of large interior space defined by the sidewalls, front and back walls, a roof, and a floor. The steel truck mainframe supports the flooring, which can include a wooden or metal platform secured to the main frame. The floor is normally bowed from front to rear in order to compensate for and provide some flexibility for heavy loads carried within the cargo area. The sidewalls and roof usually comprise material with little load bearing capability, such as fiberglass, plywood, thin sheet metal, fiberglass reinforced plywood, etc. The primary cargo load bearing structure for trucks of this type include the flooring and main frame. Typically, metal steel or aluminum bars mount at the box corners and along the edges of the box for the purpose of transferring carrying forces outward and downward to the main frame. Also, the sidewalls have been corrugated with vertically extending channels, or a portion of the sidewall may be fitted with a series of longitudinally spaced vertically extending channel members riveted to the inside or outside of the side walls, in an attempt to strengthen the sidewalls. However, these measures are generally ineffective in strengthening the sidewalls for carrying loads.
The box trucks have great utility, particularly for delivery companies that pickup, haul, and deliver a number and variety of packages of varying sizes, shapes, and weight. Currently, these cargo boxes and box trucks do not come with pre-built support system. The support system is generally individually built and installed by third parties after the cargo boxes and box trucks are built by the manufacturer. There is currently no standardized frame that can be used to build a vehicular body with a load bearing support system.
Currently, there is no mechanism to quickly and efficiently assemble or construct a permanent or temporary building structure with a load bearing system. Accordingly, the present invention proceeds upon the desirability of providing a skeleton or frame for mounting walls, roof, window, door, floor to build a mobile, permanent or temporary building structure (e.g., shed, warehouse, enclosure, shack, office, classroom, show room, exhibition hall, booth, garage, a field hospital, clinic, modular building structure and the like, collectively referred to herein as an enclosed structure) with a load bearing support system. The load bearing support system of the present invention provides one or more levels of accessories, such as shelves, hooks, racks, platforms, bins, drawers, cots, cabinets, sliding racks, hangars, benches and the like within and/or outside the building structure. Preferably, accessories can easily and reliable rotated or moved to their stored or utility positions. Also, the accessories are removably attachable so that they can be easily and efficiently reconfigured to meet a particular application.
Further, the present invention proceeds upon the desirability of providing a frame for mounting panels, sidewalls, roof and floor to build a vehicular body of a cargo box or cargo vehicle and mounting a load bearing support system for use in such cargo box or cargo vehicle. The load bearing support system of the present invention provides one or more levels of accessories, such as shelves, hooks, racks, sliding racks, cabinets, platforms, bins, drawers, cots, hangars, benches and the like within and/or outside the cargo area of the vehicle. Preferably, accessories can be easily and reliably rotated to their stored and utility positions. Also, the accessories are removably attachable so that they can be easily and efficiently reconfigured to meet a particular cargo or storage need. For example, one or more shelves can be moved up or down to accommodate varying sized packages.

Frame for building a vehicular body with a load bearing support system


A method and device are used for controlling growth of plants in pavement splits by preventing seeds from germinating and by preventing growth of plants from existing roots in the vicinity of the splits. The growth of plants is controlled for extended periods of time (2 to 20 years). A pre-emergence herbicide and a systemic herbicide are incorporated into a polymeric matrices. The polymeric matrices are formed into shaped objects, such as, bands or cords which are then inserted into splits. The split is then filled with a sealer which permits easy migration of the herbicides therethrough. The herbicides gradually released from the shaped objects at a rate sufficient to maintain a minimal effective level of herbicide outside said sealer for a predetermined period of time.

The present invention relates generally to the field of controlling the growth of plants in splits found in cement or asphalt pavements. The invention, more particularly, relates to the field of long-term control of plant growth in the splits.
Pavements are usually made of asphalt and concrete but can also be constructed by a variety of building materials such as stone, brick and cobblestone. Such pavement structures including sidewalks and curbs are usually engineered with seams and/or expansion joints. The expansion joints are intended to function to either prevent or limit the formation of cracks in the pavement caused by thermal/pressure excursions such as those caused by weather.
Most commonly, cracks are caused by natural processes such as freezing and thawing of the pavement caused by weather conditions. Because of the freezing and thawing, the integrity of the joints in the pavement may be reduced or worse, cracks may form in the pavements. Further, enlargement of both the manufactured or naturally created splits can occur during severe cold weather when water infiltrates into the splits. As used in this specification and the appended claims the term "split" is defined to mean any type of divide in the pavement including cracks, joints and seams.
The problem associated with splits in the pavement can be amplified by plants. The joints, the seams and the cracks in the pavement serve as natural collection points for wind dispersed plant seeds. Moisture and soil which accumulate in the cracks provide an ideal environment for plants allowing the seeds to sprout. Upon germinating, the plants accentuate the problem of crack enlargement by further inducing the cracks. Moreover, roots of plants in the soil below pavement can grow into plants through the splits in the pavement.
In addition to enlarging the splits, the plants growing in the splits can also cause litter problems because they are capable of trapping litter, such as, paper wrappers as they are being blown about by the wind. This problem is especially troublesome on aircraft runways, tax-ways and aprons. Such plant growth may obscure the view of airport runway lights endangering the lives of airplane passengers. Moreover, the litter which accumulates in the runways due to the growth of plants in pavement splits can even be sucked into jet engine or into reciprocating engine intakes, to cause damage or malfunction of engines.
To alleviate the plant problem, a quick temporary solution is provided by mowing. A more permanent method has been developed which requires the splits to be routed and then sealed with either asphalt or butyl sealants. In the most severe cases, repaving the runway, taxi-way or apron may be required.
Although routing and sealing is effective for removing plants that have grown in the splits at the time the pavement is either routed and sealed or repaved, the method is not a solution for the long-term control of the plant problem in splits. That is, if the splits have been routed and sealed, the seal will eventually deteriorate thereby reopening the splits. Once the splits are reopened, the growth of plants in the reopened splits presents the same problems as those discussed above. Therefore, routing and sealing the splits does not alleviate the problem of plant growth in splits (including cracks, joints or seams). It continues to be a recurring problem.
It is known in the art that plant seedlings may be controlled by the use of pre-emergence herbicides. For example, Soper, U.S. Pat. No. 3,257,190, Soper, U.S. Pat. No. 3,111,403, Lignowski and Scott, Trifluralin and Root Growth, 12 Plant & Cell Physiology 701 (1971), and Eshel and Katan, Effect of Dinitroanilines on Solanaceous Vegetables and Soil Fungi, 20 Weed Science 243 (1972), all teach the use of 2,6-dinitroaniline as a herbicide which eliminates germinating seedlings. Furthermore, Koestler, U.S. Pat. No. 4,360,376 teaches incorporating 2,6-dinitroaniline into a microcapsule capable of releasing it. Although these references teach the use of pre-emergence herbicides to control the growth of plants, they do not provide a practical solution which may be used in long-term control of plant growth in pavement splits, including joints, cracks or seams.
By applying a herbicide in a single application to a split (a crack, joint or seam) in the pavement, the initial concentration of herbicide is much greater than needed. However, the concentration becomes too low to be a truly effective retardant with the passage of time. The concentration of herbicide in the applied area is lowered because of physical, chemical and even biological activity.
Therefore, it is desirable to provide a method and device in which the herbicide can be metered out in the split at a preselected rate. Additionally, it is desirable to provide a method and device which protects the herbicide from degradation and physical loss from the split.
Another problem with using pre-emergence herbicides, such as 2,6-dinitroaniline is that such herbicides do not eliminate existing plants. In other words, the growth of perennial plants from existing roots is largely unaffected by presence of a pre-emergence herbicide in the split.
A problem with prior art controlled release devices such as those disclosed in U.S. Pat. No. 3,864,114 (Green) is that the operation of the device disclosed in that patent is based on leaching the herbicide. Water penetrates the device and leaches out the herbicide. Generally, water degrades the herbicide in a relatively short period of time of about 2 to 6 weeks.
In light of the problem encountered by the growth of plants in pavement cracks, joints, and seams, there presently exists a need for a method and/or device which prevents such growth for extended periods of time. Such an arrangement would help minimize the amount of destruction and danger caused by plant growth in highways, airport runways, sidewalks and generally in any type of use of concrete and asphalt.
Thus, one object of the present invention is to provide a product and a method for controlling, for a prolonged period of time (2 to 10 years) the growth of plants in splits by preventing seeds from germinating and also by preventing the growth of plants from existing roots.
Another object of the present invention is to provide a controlled-release device and a method in which the release of the herbicide is driven by temperature.
A further object of the present invention is to provide a controlled release device and method in which the release rate of the herbicide and its effectiveness can be predetermined.
A still another object of the present invention is to provide a controlled release device and method in which the herbicide is protected from chemical and biological degradation prior to being released from the device.
A yet further object of the present invention is to provide environmentally superior controlled release herbicide device and method in which the herbicide is localized and does not spread far into the soil surrounding the system.
A still further object of the present invention is to provide herbicidal device which can be easily inserted into the splits and which is retained in the splits for a prolonged period of time.
Other objects of the present invention will become apparent to those skilled in the art upon studying this disclosure.

Method and composition for protecting pavement structure from growth of seeds and roots in splits of the structure


An ambient temperature control apparatus used for measuring ambient temperature. The apparatus has a bottom plate, a panel fitting apparatus, an external mask, and a temperature control device. The panel fitting apparatus is disposed on the bottom plate and is suitable for use to fix a liquid crystal panel. The external mask is detachably mounted on the bottom plate to form a cavity, in which the panel fitting apparatus and the liquid crystal panel are enclosed. The external mask includes at least a window allowing the photometer to measure the liquid crystal panel therefrom. The temperature control device mounted to the external mask is suitable to control the temperature variation of the cavity.

1. Field of the Invention
The invention relates in general to a temperature control apparatus, and more particular, to an ambient temperature control apparatus used for measuring a liquid crystal display. The ambient temperature control is operative to change the ambient temperature of the liquid crystal panel, so as to prevent it from affecting the ambient temperature of the measurement equipment; therefore, the precision of the measurement equipment is ensured.
2. Related Art of the Invention
Having the features of small volume, light weight, low driving voltage, low power consumption, and portability, the liquid crystal display products have been broadly applied. The application extends from products from daily life to high-end industrial production, including clocks, watches, computers, televisions, communication products, medical instrument, aviation transportation, industrial equipment, and special armaments. The high-quality liquid crystal displays tend to gradually replace the conventional color cathode ray tubes.
The conventional fabrication process of liquid crystal displays includes the following steps. A glass substrate is cleaned (pre-cleaning process). An indium tin oxide (ITO) conductive layer is formed on the glass substrate (pattern process). An alignment film is formed on the conductive layer (alignment and pattern transfer process). A spacer is formed between the two glass substrates. An insulating epoxy resin material is printed around the glass substrates (sealant coating process). The substrates are then adhered to each other (assembly and sealing process), and cut into individual dies. The liquid crystal is injected and the assembled substrates are then sealed by pressure, followed by the processes of corner rounding of the glass substrates, inspection of liquid crystal panel, adhesion of polarizer, and final inspection.
The above inspection process of the liquid crystal panel includes inspection of optical characteristics, such as the inspections of brightness, luminance and response time. As the luminance and response time of liquid crystal displays will vary according to ambient temperature, there is a need to perform the inspection of the ambient temperature dependent luminance and response time.
The conventional measurement apparatus of liquid crystal panels is shown in FIG. 1. Referring to FIG. 1, the measurement apparatus 100 includes at least a reaction chamber 102 and a photometer 104. In this example, a colorimeter is used. The liquid crystal panel 108 is fixed in the reaction chamber 102 via the panel fitting apparatus 106. The photometer 104 is used to measure the liquid crystal panel 108. Further, the measurement apparatus 100 includes a temperature control apparatus (not shown). When the temperature variation is required, the temperature of the reaction chamber 102 is either increased or decreased to perform the measurement.
However, the photometer 104 has a certain operating temperature range, for example, the operating temperature range for the above photometer (colorimeter) is about 23° C.±3° C. When the temperature variation of the liquid crystal panel 108 at either a higher or a lower temperature has to be measured, the temperature variation (increased or decreased) reflects the variation of the whole reaction chamber 102. As a result, the photometer 104 is frequently operated at a temperature out of the operating temperature range. The precision and accuracy of the measurement obtained therefrom is thus unreliable.

Apparatus for measurement optical characteristic of a display panel


A region on a surface side of a sample is irradiated with a Ga ion beam to form a first laminar portion having a thickness of 50-200 nm small enough to allow the transmission electron microscopic observation. While the sample is being heated within a transmission electron microscope, a process in which silicide is being formed is observed at the first laminar portion. Thereafter, a second laminar portion is formed in a thick region of the sample, similarly to the first laminar portion. Then, the first and second laminar portions are comparatively observed in a non-heated state with the transmission electron microscope. If observation results of the two laminar portions in the non-heated state are the same, a result of observing the first laminar portion during the heating is taken to represent a phenomenon in a bulk state. If observation results of the two laminar portions are different from each other, the result of observing the first laminar portion during the heating is taken to represent a unique phenomenon resulting from the heating of the sample in a thin film state. Thus, a transmission electron microscopic observation involving the simultaneous heat treatment is correctly carried out with a few samples.

The present invention relates to an improvement in a method for observing a reaction process by the transmission electron microscopy.
For observation of material structure by the transmission electron microscopy, a sample cut out of the material needs to be processed into a small thickness on the order of several tens to several hundred nm that enables the sample to transmit an electron beam.
A method of preparing transmission electron microscopic samples for observation under heating is presented, for example, in a literature "DENSHI KENBIKYO GIHO (Electron Microscopy), edited by Electron Microscopy Society of Japan, Kanto Branch, published by Asakura Shoten, 1991, pp. 119-130". In this method of preparing transmission electron microscopic samples, a sample piece cut out in a specified size is subjected to a mechanical grinding process so that its center becomes the thinnest. The sample piece is further subjected to a thinning process by ion milling or chemical etching. This processing is completed when the sample gets partly holed. The sample obtained in this way is observed by transmission electron microscopy in a wide area around the hole wherein the sample has a thickness of several tens to several hundred nm.
The above sample preparing method is described in detail with reference to FIGS. 6A, 6B, 7, 8A, 8B, 9A, 9B, 10A and 10B.
As shown in FIGS. 6A and 6B, a rectangular piece 24 of a 1 mm-3 mm square is cut out of a wafer 21. Reference numeral 22 denotes a substrate, and 23 denotes a surface of the piece prior to heat treatment. Two such pieces 24 are prepared. Then, as shown in FIG. 7, the two pieces 24, 24 are bonded together by thermosetting resin 25 with their surfaces 23 facing each other, and then baked for about 3 hours at 180.degree. C. As a result, a sample 26 is produced.
Next, as shown in FIG. 8A, the sample 26 is attached to a bottom surface of a weight 27a of a grinding tool 27, with the bonded surfaces of the sample 26 being vertical to the weight bottom surface (see FIG. 8B). Then, the sample 26 is ground to a thickness of about 100 .mu.m by rotating a rotary grinder 29 while an abrasive 28 is being fed. In this process, the sample 26 is abraded by successively changing the type of the abrasive 28 and of the rotary grinder 29 until a ground surface has no flaws. In this way, the surface of the sample 26 gradually changes from a coarse state to a fine state.
Next, as shown in FIG. 9A, the sample 26 is fixed on a sample mount 30 of a dimple grinder, facing down the surface 5 of the sample 26 ground by the rotary grinder 29. Then, a region 32 around the bonded part is ground into a mortar shape by a dimpler 31, as shown in FIG. 9B and FIG. 9C (a sectional view as indicated by arrows C--C of FIG. 9B).
Next, as shown in FIG. 10A, an ion beam 33 is applied to the opposite surfaces of the sample 26 by ion milling equipment. Thus, the sample 26 is ion milled to be thinned until a central portion of the area 32 has a thickness on the order of several tens to several hundred nm. The reason for using the ion milling technique to process the sample into a thickness on the order of several tens to several hundred nm is that there is a limit in thinning the sample through mechanical polishing by the rotary grinder 29, dimple grinder or the like.
The sample 26 thus obtained, shown in FIG. 10B, is fixed to a heatable holder of a transmission electron microscope. Then, changes in the state at the bonded part 34 are observed while heating is effected (with heating conditions changed).
Another method of preparing a sample for observation by the transmission electron microscopy different from the foregoing sample preparing method is described in Japanese Patent Laid-Open Publication HEI 5-180739. In this sample preparing method, a piece of specified dimensions is cut out of a material, and then the piece is subjected to a mechanical cutting process so as to be formed into an L-shape or a convex shape in cross section with its observation part left. After that, the observation part is further thinned by a convergent charged-particle beam, whereby a sample having a thickness of 0.1 .mu.m is obtained.
The sample obtained in this way is fixed to a heatable holder of a transmission electron microscope. Then, changes in the state of the material piece around the observation surface is observed while heating is effected (with heating conditions changed).
However, when reaction process is observed with the sample prepared by either of the above conventional methods, there arises a problem as described below.
That is, for transmission electron microscopic observation of state changes of a material under heating, it is necessary to process the sample to a small thickness on the order of several tens to several hundred nm such that the sample can transmit an electron beam. Such a small thickness of the sample increases a ratio of cross sectional area to volume of a region where changes in state occur when heated, and also increases the area of contact with the vacuum. Thus, the heating of the sample having a film thickness small enough to transmit the electron beam would involve conditions different from the conditions in heating a sample in a wafer state as shown in FIG. 6A or a sample having a film thickness that is too large to transmit the electron beam.
Accordingly, with the experimental sample as prepared by either of the above conventional methods, a reaction process similar to that which actually occurs in a wafer state would not be able to be observed.
Thus, it could be conceived that after a thick-film sample is formed and heated, the sample is processed to such a thickness as to transmit the electron beam, and then observed by a transmission electron microscope. However, in this case, although observation of the state after the heating process is possible, observation of the state during the heating (i.e., an intermediate state) is impossible.
Of course, if a large number of wafers or thick-film samples that have been heated at various temperatures are prepared and processed into a thickness small enough to transmit the electron beam and then observed by a transmission electron microscope, intermediate states will be observed. Unfortunately, however, there arises a problem that numbers of samples would be needed. Further, there is another problem that because the heating temperature cannot be varied continuously, there may be cases in which changes in reaction process at certain temperatures cannot be observed.

Method for observing a reaction process by transmission electron microscopy


A lock-aid circuit and method is applied to a phase lock loop (PLL) having a voltage controlled oscillator (VCO), wherein the lock aid is coupled with the input of the VCO. In one example, the lock aid includes a Schmitt trigger having an output, a switch having an output and an input coupled to the output of the Schmitt trigger, and a voltage controlled current source coupled with the output of the switch.

Phase locked loops are commonly used on various circuit applications, and may be used as clock multipliers or clock sources. For instance, an input clock of 10 MHz can be multiplied by a phase locked loop to yield a signal at 1 GHz, preferably in phase alignment with the 10 MHz clock signal.
In electronic systems, good clock distribution is very important to the overall performance of the product. Unwanted clock skew and jitter are two phenomena that may result from poor clock distribution, thus causing problems in the design and operation of the electronic systems. Techniques have been developed using phase locked loops (PLLs) to successfully manage these problems and reduce both to manageable levels, and PLLs are widely used in electronic circuits.
Conventional phase lock loops are discussed in many publications, examples of which include "PLL Synthesizers: A Switching Speed Tutorial", Bar-Giora Goldberg, Microwave Journal, September 2001, see http://www.peregrine-semi.com/pdf_pll_switching_speed_giora.pdf. Further examples include Robert Adler, "A Study of Locking Phenomena in Oscillators" Proceedings of the IEEE, October 1973, pp. 1380-1385; Roland Best, "Phase Lock Loops", McGraw-Hill, New York, 1984; and "Electronic Circuits Design and Applications", U. Tietze, Ch. Schenk, Springer-Verlag (1991) pp. 164-167.
A typical phase locked loop circuit is shown in FIG. 1, having a phase/frequency detector, a charge pump, a filter, a voltage controlled oscillator (VCO) or variable frequency oscillator (VFO), and a divider (shown to divide by N). The phase/frequency detector sends to the filter information about the frequency and phase of the reference signal relative to the feedback clock signal. The filter integrates this information into a voltage. The VCO converts the voltage information into a higher speed/frequency output signal, which is fed back into the phase/frequency detector through the divider. The divider takes the higher speed frequency and divides it down for comparison to the reference signal by the phase/frequency detector.
As recognized by the present inventors, it is desirable to reduce the lock time for PLLs in certain applications, such as frequency synthesizers. For example, when frequency hopping is used in modern wireless networks (for example, 3G cellular, WCDMA, WLAN, and Bluetooth), the time to settle is considered "dead time" where no information is transmitted, and thus time is wasted. Speeding up the lock time increases the effective data rate and thus the value of such networks. Another example would be in wireline networks, where a reduced lock time helps to minimize the amount of data lost. That is, if a long string of zeros or ones is in the data path and the PLL loses lock, reacquiring lock sooner results in more data recovered.
A conventional way to speed up a PLL 20 is shown in FIG. 2 and includes a second charge-pump (CP) 32, or extra current sources, in parallel with a first charge pump 28 but with more current. This additional source 32 of current helps charge or discharge the main capacitor, or loop filter capacitor, faster and thus increases the loop bandwidth. However, since this changes the loop dynamics, the PLL 20 may more easily become unstable and oscillate. Conventional attempts to restore stability, such as switching in resistors to reduce the loop bandwidth, change the loop dynamics themselves and further add to the settling time of the PLL. Stability is therefore a major disadvantage of using conventional PLL speed-up techniques.
Additionally, conventional techniques to speed up PLL lock time may require some method of determining when the PLL is locked so that the added charge pump or current source can be disconnected for final lock, such as lock-detector circuitry. This adds cost and complexity to the design, and is an additional disadvantage of conventional techniques to speed up PLL lock times.
Furthermore, conventional techniques to speed up PLL lock times do not prevent frequency runaway of the locked PLL. Frequency runaway occurs when a locked PLL comes out of lock and cannot re-acquire lock.
As recognized by the present inventors, what is needed is a circuit and method for reducing the lock-time of a phase lock loop circuit without changing the feedback loop characteristics.
It is against this background that various embodiments of the present invention were developed.

Circuit and method to speed up PLL lock-time and prohibit frequency runaway